Tzu-Yu Chou¹, Hsin-Hui Chiu², Wen-Yih Isaac Tseng³, Marius Menza⁴, Bernd Jung⁴, and Hsu-Hsia Peng^1
1Department of Biomedical Engineering and Environmental Sciences, Hsinchu, Taiwan, ²Department of Pediatrics, Taipei Medical University Hospital, Taipei, Taiwan,³Center for Optoelectronic Biomedicine, College of Medicine, National Taiwan University, Taipei, Taiwan, ⁴Medical Physics, Department of Radiology, University Hospital Freiburg, Freiburg, Germany

Marfan syndrome (MFS) is an inherent mutation of encoding the fibrillin-1 protein. This protein is in charge of forming microfibrils, which is a basic material to build the elastic fibers. In this study, we used dark-blood phase-contrast (PC) MRI to compute myocardial wall motion velocity for MFS patients and age-matched normal controls. MFS patients presented higher systolic pVz values, shorter diastolic TTPz and TTPr and achieved peak diastolic twist velocity in an earlier phase. In conclusion, systolic pVz, diastolic TTPz and TTPr, and twist velocity provide satisfied information to diagnose myocardial function of MFS patients.

Oliver Kraus¹, Lukas Winter¹, Matthias Dieringer^1,2, Andreas Graessl¹, Jan Rieger³, Celal Oezerdem¹, Fabian Hezel¹, Andre Kuehne^4,5, Patrick Waxmann⁶, Harald Pfeiffer⁶, and Thoralf Niendorf^1
1Berlin Ultra-High Field Facility, Max-Delbrueck Center, Berlin, Germany, ²Working Group on Cardiovascular MR, Experimental and Clinical Research Center (ECRC), Berlin, Germany, ³MRI.TOOLS GmbH, Berlin, Germany, ⁴Center for Medical Physics and Biomedical Enginieering, Medical University of Vienna, Austria, ⁵MR Center of Excellence, Medical University of Vienna, Austria, ⁶Medical Physics and Metrological Information Technology, Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany

In highfield cardiac MR flip angles are often limited by SAR constraints. To offset SAR constraints this study demonstrates the benefit of local transmit coils versus body/volume coil excitation. The applicability of a local 4-channel transceiver array is examined. Transmission performance and efficiency of the proposed array are explored. Our results demonstrate that larger flip angles can be achieved with local transceiver versus body coils before SAR limits are reached. The use of multi-channel transceiver coils underlines the need and value of local SAR considerations with the goal to attenuate SAR hotspots and to increase the applicable RF input power.

Maythem Saeed¹, Hisham Z. Bajwa¹, Loi Do¹, Mohammed SA Suhail^1,2, Steve W. Hetts¹, and Mark W. Wilson^1
1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, United States, ²Radiology, University of California, San Diego, San Diego, California, United States

Clinical trials suggest microvascular obstruction (MVO) portends a poor prognosis and is independent of infarct size. We aimed to provide evidence that MVO inhibits infarct healing and enhances compensatory LV hypertrophy. Cine and DE-MRI was performed in animals with major and minor MVO. Cine MRI showed that animals with major and persistent MVO have larger infarct mass and remote hypertrophied myocardium compared with animals with minor MVO. MVO caused greater and persistent decline in ejection fraction and increase in LV volumes compared with animals with minor MVO. MRI illustrates that MVO inhibits infarct healing, accentuates LV hypertrophy/dysfunction.

Kai Jiang^1,2, Wen Li^1,2, Raymond F. Muzic^1,3, and Xin Yu^1,3
1Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, United States, ²Case Medical Center, Case Western Reserve University, Cleveland, Ohio, United States, ³Department of Radiology, Case Western Reserve University, Cleveland, Ohio, United States

In this study, a fast T₁ mapping method was proposed for quantification of both the arterial input function and the kinetics of Mn²⁺ uptake in mouse myocardium in manganese-enhanced MRI (MEMRI) studies. A compartment model was developed for in vivo estimation of Mn²⁺ uptake and efflux rates by fitting the model to MEMRI data.

Syue-Yu Jhang¹ and Teng-Yi Huang^1
1National Taiwan University of Science and Technology, Taipei, Taiwan

Cardiac phase (CP)-resolved steady-state free-precession (CP-SSFP) imaging has been shown able to detect myocardial blood oxygen level-dependent (BOLD) signal changes under pharmacological stress and myocardial ischemia at rest. However, the noise level of images affects the reliability and sensitivity of the BOLD contrast obtained by using CP-SSFP. This study aims to combine an automatic cardiac-phase detection, deformable image registration and temporal averaging to improve quality of CP-SSFP cardiac images. The proposed method significantly increased CNRs of the images acquired during both systole and diastole and could be a practical tool for CP-SSFP-based myocardial BOLD applications.

Daniel Jeong¹, Peng Lai², Karl K. Vigen¹, Kang Wang³, James H. Holmes³, Kevin M. Johnson⁴, Oliver Wieben^1,4, Mark L. Schiebler¹, and Christopher J. Francois^1
1Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States, ²Global MR Applications and Workflow, GE Healthcare, Menlo Park, CA, United States, ³Global MR Applications and Workflow, GE Healthcare, Madison, WI, United States, ⁴Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, United States

In this study we compared the accuracy of measurements for left ventricular function and volume in subjects using 2D balanced SSFP and novel 3D kat ARC sequences. Left ventricle ejection fraction (LVEF), end diastolic volume (EDV), and end systolic volume (ESV) measurements were obtained in patients and healthy volunteers. No significant differences in LV ejection fraction or volume measurements were observed between the two sequences, with 3D kat-ARC sequence generating LV measurements which were non-inferior to 2D SSFP. Consequently, this approach should enable substantial improvements in scanner time efficiency without sacrificing diagnostic accuracy.

Maythem Saeed¹, Mohammed SA Suhail^1,2, Loi Do¹, Steve W. Hetts¹, and Mark W. Wilson^1
1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, United States, ²Radiology, University of California, San Diego, San Diego, California, United States

The main processes that are responsible for acute and chronic mechanical changes in the left ventricle (LV) post-acute myocardial infarction (AMI) include resolution of transitive natural progression of AMI and long-term mechanical changes (contraction/relaxation and dyssynchrony). This study was designed to monitor and compare biventricular circumferential and longitudinal strain/strain rate in large animals subjected to infarction. Time resolved cine and tagged MRI have high specificity in monitoring circumferential and longitudinal strain changes over the course of weeks after myocardial infarction in left and right ventricles. MRI also showed the interaction between LV and RV dysfunction in acute and chronic infarct.

Dagmar Hartung¹, Serghei Cebotari², Igor Tudorache², Karolina Theodoridis², Tanja Meyer², Alexandru Mogaldea², Robert Ramm³, Katja Hueper¹, Frank Wacker¹, Andres Hilfiker³, and Axel Haverich^2
1Radiology, Hannover Medical School, Hannover, Germany, ²Division of Cardiothoracic, Transplantation, and Vascular Surgery, Hannover Medical School, Hannover, Germany, ³Leibniz Research Laboratory for Biotechnology and Artificial Organs, Hannover Medical School, Hannover, Germany

In various congenital heart diseases reconstruction of the right ventricular outflow tract (RVOT) is necessary. Pericardium is the currently used material. To improve longterm graft survival new approaches based on regenerative medicine are being developed. We evaluated the feasibility of a novel tissue engineered (TE) graft composed of an allogeneic TE valve combined with an autologous vascularized patch of small intestine (AutoVaM) for RVOT-reconstruction in pigs by MRI. A graft consisting of a TE valve combined with a pericardial patch served as control. Morphological and functional properties of the new AutoVaM-graft were superior to the conventional pericardial graft for RVOT-reconstruction.

George Gentchos¹, Caitlin Baran², Michael Toth^3,4, Hirak Der-Torossian⁵, Marion Couch⁵, and Kim Dittus^6
1Radiology, University of Vermont, Burlington, VT, United States, ²College of Medicine, University of Vermont, Burlington, Vermont, United States, ³Department of Medicine, University of Vermont, Burlington, Vermont, United States, ⁴Molecular Physiology and Biophysics, University of Vermont, Vermont, United States, ⁵Surgery, University of Vermont, Burlington, Vermont, United States, ⁶Medicine, University of Vermont, Burlington, Vermont, United States

Skeletal muscle dysfunction has been demonstrated by our group in patients with cancer. It is theorized that prolongation of myosin-actin relaxation time may cause diastolic dysfunction. Patients in this cohort underwent cardiac MRI for assessment of LV function using VEC-MRI, however we are exploring a novel technique using wall motion kinetics using semi-automated volumetric analysis to assess systolic and diastolic function. Our study shows good correlation with VEC-MRI of decreased rate of early diastolic filling (passive relaxation) as a marker of diastolic dysfunction. Additionally, our study suggests subtle abnormalities in systolic function using this technique despite preserved global LV function. This technique is simpler and quicker to analyze than VEC-MRI for evaluation of diastolic dysfunction.

Tobias Wech^1,2, Andreas Schindele³, Victoria L Thornton⁴, Alfio Borzi³, Herbert Köstler^1,2, and Jurgen E Schneider^4
1Department of Radiology, University of Würzburg, Würzburg, Germany, ²Comprehensive Heart Failure Center, University of Würzburg, Würzburg, Germany, ³Institute of Mathematics, University of Würzburg, Würzburg, Germany, ⁴Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom

Cine-MRI is a well-established tool to assess global cardiac function in rodent models of cardiovascular disease. 3D techniques provide improved signal-to-noise, which could be utilized to increase spatial and / or temporal resolution at the cost of increased acquisition time. The aim of this study was to develop optimised compressed sensing reconstruction as an approach to accelerate 3D cine-MRI in mice at 9.4T. Fully sampled 3D cine data sets acquired in three normal mice were up to 15-fold undersampled in post-processing and subjected to compressed sensing reconstruction, using algorithms with and without additional Total Variation constraint. Low RMSE-values even for high acceleration factors (R=15) indicated that compressed sensing enables significant time savings in 3D cine acquisitions.

Bailiang CHEN^1,2, Laurent Bonnemains^1,2, Pauline FERRY^1,2, Anne MENNI^1,2, Marine BEAUMONT^1,3, Jacques FEBLINGER^1,2, and Freddy ODILLE^1,2
1IADI, Université de Lorraine, Nancy, Lorraine, France, ²U947, Inserm, Nancy, Lorraine, France, ³CIC-IT 801, Inserm, Nancy, Lorraine, France

Conventional cardiac function assessment is performed by cine MRI with whole heart coverage using a stack of ECG-gated 2D SSFP sequence. Generally, 12-14 slices need to be acquired in successive breath-holds, requiring 6-10min altogether. Quantitative function assessment can also be tedious due to the need of segmentation. Here, an optimized cardiac function exam is proposed using: i) a free-breathing, 2D multi-slice SSFP sequence with 3D GRICS motion correction (4-5min in total); ii) a semi-automatic segmentation technique based on geometrically constrained fuzzy c-means. Its efficacy and robustness is demonstrated in 5 Duchenne muscular dystrophy (DMD) patients with difficulty in breath holding.

Christie McComb^1,2, David Carrick³, Rosemary Woodward^2,4, John McClure², Aleksandra Radjenovic², Colin Berry^2,3, and John Foster^1,2
1Clinical Physics, NHS Greater Glasgow & Clyde, Glasgow, United Kingdom, ²BHF Glasgow Cardiovascular Research Centre, Glasgow, United Kingdom, ³Cardiology, Golden Jubilee National Hospital, Glasgow, United Kingdom, ⁴MRI, Golden Jubilee National Hospital, Glasgow, United Kingdom

Myocardial infarction (MI) causes contractile dysfunction in the affected tissue, which can be assessed by using DENSE (Displacement ENcoding with Stimulated Echoes) to quantify myocardial strain. Peak circumferential strain and strain rate were measured in 50 patients within 7 days of MI, and 47 returned for a follow-up scan after 6 months. Recovery of contractile function was observed in infarcted myocardial segments, and also in segments adjacent to infarction. Changes in the mechanical properties of myocardium following MI are complicated, but it appears that a reduction in infarct size at follow-up is associated with a greater recovery in contractile function.

Erica Dall'Armellina¹, Nicole Seiberlich², Keith Channon¹, Adrian Banning³, Raj K Kharbanda³, Colin Forfar³, Bernard Prendergast³, Stefan Neubauer¹, Robin Choudhury¹, and Jurgen E. Schneider^1
1RDM Cardiovascular Medicine, Oxford University, Oxford, Oxon, United Kingdom, ²Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States,³Heart Centre, Oxford NHS University Hospitals, Oxon, United Kingdom

Cardiovascular magnetic resonance (CMR) scanning in patients with acute myocardial infarction (MI) is challenging due to potential arrhythmias and difficulties in breath-holding. New free-breathing and free-gating through-time radial GRAPPA sequences for real time imaging are available. In patients with acute ST elevation MI, we demonstrated the feasibility and accuracy of real time imaging with through-time radial GRAPPA and only 16 calibration data sets for the assessment of LV function in comparison to standard breath-hold techniques.

Giorgos Papanastasiou^1,2, Michelle Williams², Mark Dweck², Saeed Mirsadraee¹, Nick Weir³, Shirjel Alam², Colin Stirrat², David Newby^1,2, and Scott Semple^1,2
1Clinical Research Imaging Center, University of Edinburgh, Edinburgh, Lothian, United Kingdom, ²Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, Lothian, United Kingdom, ³NHS Medical Physics, University of Edinburgh, Edinburgh, Lothian, United Kingdom

My PhD focuses in modeling and quantification of myocardial blood flow (MBF) using dynamic contrast enhanced magnetic resonance (DCE-MRI) which can potentially be used for the diagnosis and prognosis of coronary artery disease and also the assessment and/or planning of therapy and intervention. Furthermore, I work in a multimodality cross-validation study of MBF using DCE-MRI, computed tomography perfusion and positron emission tomography perfusion in patients with coronary artery disease. Clinically, we aim to overcome critical limitations of individual techniques and use the merits of each technique to gain a better understanding of MBF at the clinical setting.

Hsin-Jung Yang¹, Roya Yumul¹, Richard Tang¹, Ivan Cokic¹, Michael Klein², Avinash Kali¹, Olivia Sobczyk², Behzad Sharif¹, Jun Tang¹, Xiaoming Bi³, Sotirios Tsaftaris⁴, Diabao Li¹, Antonio Conte¹, Joseph Fisher², and Rohan Dharmakumar^1
1Cedars Sinai Medical Center, Los Angeles, California, United States, ²University of Toronto, Toronto, ON, Canada, ³Siemens Medical Solutions, IL, United States, ⁴IMT Institute for Advanced Studies Lucca, Lucca, Italy

Our study evaluated the feasibility of a non-invasive stress-testing paradigm using a precisely targeted partial pressure of arterial CO2 (PaCO2) to induce myocardial hyperemia, and compared this response to intravenous adenosine using myocardial blood oxygenation dependent MRI. This is the first proof-of-concept study to demonstrate that precisely controlled hypercapnia can induce myocardial hyperemia equivalent to that induced by adenosine infusion under conditions of health and coronary narrowing. Coupled with BOLD MRI, this approach points to a new opportunity for a truly non-invasive cardiac stress test. Nevertheless, human studies are needed to examine the practical utility of this approach.

Silvio Pflugi^1,2, Sébastien Roujol¹, Mehmet Akçakaya¹, Keigo Kawaji¹, Murilo Foppa¹, Bobby Heydari³, Beth Goddu¹, Kraig V Kissinger¹, Sophie Berg¹, Warren J. Manning^1,4, Sebastian Kozerke², and Reza Nezafat^1
1Department of Medicine, Beth Israel Deaconess Medical Center / Harvard Medical School, Boston, MA, United States, ²Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, ³Department of Medicine, Brigham and Women Hospital and Harvard Medical School, Boston, MA, United States, ⁴Department of Radiology, Beth Israel Deaconess Medical Center / Harvard Medical School, Brookline, MA, United States

Physiologic stress CMR perfusion is challenging due to the patients’ inability to breath-hold after exercise. Perfusion imaging is commonly performed using Cartesian sampling of k-space. Alternative sampling schemes, such as radial or spiral, have demonstrated reduction of dark-rim artifacts in the myocardium, which are commonly observed in acquisitions with Cartesian sampling. However, the comparison of Cartesian and non-Cartesian CMR perfusion after physical exercise has not yet been evaluated. In this study, we sought to compare Cartesian sampling and radial sampling for accelerated perfusion acquired after physiologic stress with an MR-compatible supine bicycle ergometer.

Hung Phi Do¹, Terrence R Jao², and Krishna S Nayak^3
1Department of Physics & Astronomy, University of Southern California, Los Angeles, California, United States, ²Biomedical Engineering Department, University of Southern California, Los Angeles, California, United States, ³Electrical Engineering Department, University of Southern California, Los Angeles, California, United States

Arterial spin labeling (ASL) is a promising technique for the assessment of myocardial perfusion and perfusion reserve without the use of exogenous contrast agent. Current myocardial ASL techniques, however, have low sensitivity due to high physiological noise. We demonstrate a statistically significant (p<0.04) reduction in physiological noise when the imaging window is shortened from 300ms to 150ms or 100ms, using rate-2 or rate-3 parallel imaging, respectively. We show that when the imaging window is longer than 150ms, cardiac motion is the dominant source of physiological noise in myocardial ASL.

Thomas Troalen¹, Julien Pugnaire¹, Thibaut Capron¹, Benjamin Robert², Monique Bernard¹, and Frank Kober^1
1Aix-Marseille Université, CNRS, CRMBM (Centre de Résonance Magnétique Biologique et Médiacle) UMR 7339, Marseille, France, ²Siemens Healthcare France SAS, Saint-Denis, France

Arterial spin labeling (ASL) in the human heart is challenging due to physiological noise. Steady-pulsed ASL (spASL) under free-breathing had been proposed to improve sensitivity. To improve robustness against respiratory motion, we present an optimization of the post-processing algorithm currently used for spASL. These improvements include dedicated rigid motion correction and a specific signal measurement algorithm. With this new approach, a greater portion (80% versus 30% formerly) of the acquired data can be used for regional perfusion assessment. This work is also a step towards calculation of myocardial perfusion maps with high spatial resolution using ASL.

Silvio Pflugi^1,2, Sébastien Roujol¹, Mehmet Akçakaya¹, Keigo Kawaji¹, Murilo Foppa¹, Bobby Heydari³, Beth Goddu¹, Kraig V Kissinger¹, Sophie Berg¹, Warren J. Manning^1,4, Sebastian Kozerke², and Reza Nezafat^1
1Department of Medicine, Beth Israel Deaconess Medical Center / Harvard Medical School, Boston, MA, United States, ²Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, ³Department of Medicine, Brigham and Women Hospital and Harvard Medical School, Boston, MA, United States, ⁴Department of Radiology, Beth Israel Deaconess Medical Center / Harvard Medical School, Brookline, MA, United States

Physiologic stress CMR perfusion provides unique information regarding the patient’s exercise capacity, hemodynamic response to exercise, and the extent of physical activity that can reproduce the patient’s symptoms during imaging. Accelerated non-Cartesian imaging has shown promises as an alternative to Cartesian sampling for CMR perfusion after physical exercise due to a) its efficient k-space sampling, b) better motion properties, and c) lower dark-rim artifacts. In this study, we sought to compare the performance of four non linear reconstruction methods for accelerated CMR perfusion with radial sampling after exercise on an MR-compatible supine bike ergometer.

Devavrat Likhite¹, Ganesh Adluru¹, Srikant Kamesh Iyer¹, and Edward DiBella^1
1UCAIR/Radiology, University of Utah, Salt Lake City, Utah, United States

Dynamic contrast enhanced MRI is maturing as a tool for quantifying cardiac perfusion. There is a need for faster data acquisition to gain coverage or spatial resolution. The use of compressive sensing based reconstruction techniques along with undersampling of data appears promising. However, there has been little study of quantification of myocardial perfusion using undersampled data. Here we present the use of radially undersampled data to quantify myocardial perfusion. Comparison of results between undersampled and 72-ray datasets shows the possibility of quantifying of myocardial perfusion with only 18 rays per image.

Davide Boschetto¹, Cristian Rusu¹, Rohan Dharmakumar^2,3, and Sotirios A. Tsaftaris^1,4
1IMT Institute of Advanced Studies Lucca, Lucca, LU, Italy, ²Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States,³Medicine, University of California Los Angeles, Los Angeles, CA, United States, ⁴Electrical Engineering and Computer Science, Northwestern University, Evanston, IL, United States

The main aim of this work is to demonstrate rigorously that myocardial BOLD signal intensity varies across cardiac phase and myocardial territories. This is achieved by demonstrating the existence of shifts across timeseries extracted from CP-BOLD MRI acquisitions in canines. The application of a circulant dictionary approach let us represent each original timeseries as a weighted version of a shifted pattern (i.e., BOLD curve) learned from the data. By comparing energy distributions among kernel shifts with Kolmogorov-Smirnov test and by a fitness function analysis, the presence of shifts is statistically proven

Regine Schmidt¹, Dirk Graafen¹, Karsten Sommer¹, Stefan Weber¹, Hanns-Christian Breit¹, and Laura Maria Schreiber^1
1Section of Medical Physics, Department of Radiology, Johannes Gutenberg University Medical Center, Mainz, Germany

The dispersion of a contrast agent bolus during myocardial perfusion MRI was investigated for a coronary bifurcation geometry with stenosis via computational fluid dynamics simulations. Simulations for different outflow conditions through the stenotic branch were performed. Results were analyzed quantitatively and semi-quantitatively. A non-negligible underestimation of myocardial blood flow (MBF) up to -16.1% and normalized upslope (NUS) up to -23.9%, and an overestimation of the myocardial perfusion reserve (index) (MPR(I)) up to 7.5% and 13.1%, respectively, were found. Furthermore, different parameters, e.g. the diffusion coefficient of contrast agent or the non-Newtonian behavior of blood, have been investigated in further simulations.

Haonan Wang¹, Neal Kepler Bangerter¹, Eugene Kholmovski², Meredith Ireene Taylor¹, and Edward V.R DiBella^2
1Department of Electrical & Computer Engineering, Brigham Young University, Provo, UT, United States, ²Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, UT, United States

Dark rim artifacts are seen in first-pass myocardial perfusion imaging and impede accurate diagnosis of ischemia even when the image quality is otherwise reasonable. Gibbs ringing and cardiac motion are thought to be the main causes of dark rim artifacts for 2D multi-slice methods. New 3D acquisitions with high degrees of undersampling are starting to be used, but the longer readout may lead to more motion-related artifacts. In this study, we demonstrate that motion can create dark rim artifacts such as those observed in a highly-accelerated 3D acquisition. The artifacts depend on phase encode orderings and the timing of motion.

Hsin-Jung yang¹, Richard Tang¹, Avinash Kali¹, Ivan Cokic¹, and Rohan Dharmakumar^1
1Cedars Sinai Medical Center, Los Angeles, California, United States

Myocardial BOLD MRI is an emerging non-contrast approach in the assessment of ischemic heart disease. Most commonly used myocardial BOLD MR approaches utilized weighted imaging (T2-weighted, T2*-weighted or bSSFP). In spite the benefits these techniques have provided to the advancement of myocardial BOLD imaging, several limitations continue to persist.. Recently, we developed a fast, free breathing 3D T2 mapping technique that utilizes 100% imaging efficiency, which allows for full coverage of the whole left ventricle within 5 minutes. In this study, we demonstrate the practical utility of the approach using a canine model subjected adenosine stress.

Hao Li¹, Bin Chen¹, Xiaoying Wang^1,2, and JUE ZHANG^1,3
1Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, Beijing, China, ²Radiology, Peking University First Hospital, Beijing, Beijing, China, ³College of Enigneering, Peking University, Beijing, Beijing, China

Segmentation of internal kidney structures is essential for functional evaluation in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Manual morphological segmentation of cortex, medulla and cavities remains difficult and time-consuming. In this paper, a semi-automated segment method for magnetic resonance renal images is proposed, which is based on Curvelet transform and Snake Model. Compared quantitatively with manual contour, the proposed segmentation showed satisfactory performance, and could become a feasible preprocessing tool for renal segmentation and renal functional analysis.

Qian Tao¹, Pieternel van der Tol¹, Hildo J. Lamb¹, and Rob J. van der Geest^1
1Department of Radiology, Leiden University Medical Center, Leiden, Zuid Holland, Netherlands

Myocardial tissue characterization by MR T1 mapping has potentially important clinical applications in a wide spectrum of cardiovascular disease. However, the current MOLLI technique allows limited heart coverage and requires breath-hold. To make whole heart free-breathing T1 mapping possible, motion correction methods were developed in parallel with a new MRI T1 mapping sequence to deal with the in-plane and through-plane motion which arises from the free breath. The proposed motion correction methods largely reduced the T1 mapping error, and made whole heart free-breathing T1 mapping possible both prior to and after contrast injection.

Serena Y Yeung¹, Nii Okai Addy¹, R Reeve Ingle¹, Bob S Hu^1,2, and Dwight G Nishimura^1
1Electrical Engineering, Stanford University, Stanford, CA, United States, ²Palo Alto Medical Foundation, Palo Alto, CA, United States

High-resolution coronary magnetic resonance angiography (CMRA) enables finer depiction of coronary vessel detail, but at the same time introduces the challenge of compensating for a loss in SNR. In this work we demonstrate the ability of nonrigid 3D+t image registration to correct for interphase cardiac motion in multiphase acquisitions, thus enabling SNR gain through temporal averaging of the aligned images. 3D+t registration has two major advantages over standard 3D registration in this application: transformations are temporally as well as spatially smooth, and registration is performed globally without bias towards a specifically chosen reference image.

Bradley D Allen¹, Maria Carr¹, Michael O Zenge², Michaela Schmidt², Mariappan S Nadar³, Bruce Spottiswoode⁴, Jeremy D Collins¹, and James C Carr^1
1Department of Radiology, Northwestern University, Chicago, IL, United States, ²Siemens AG, Healthcare Sector, Erlangen, Bavaria, Germany, ³Siemens Corporate Technology, Princeton, NJ, United States, ⁴Siemens Healthcare USA, Inc., Chicago, IL, United States

Clinical CMR is an important diagnostic tool but can be limited by the requirement for patient-breath holding to achieve high quality images. Accelerated CMR acquisitions can help to overcome this challenge. Iterative k-t-sparse SENSE reconstruction with L1 regularization along one spatial and temporal dimension is an investigational acceleration technique that has the potential to dramatically reduce scan time. In this study, we applied this technique in patients undergoing CMR. While there was some regional variability in image quality, scan times were reduced by >50% per slice.

Cristian Rusu¹, Rohan Dharmakumar^2,3, and Sotirios A. Tsaftaris^1,4
1IMT Institute for Advanced Studies Lucca, Lucca, Italy, ²Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States, ³Medicine, University of California, Los Angeles, CA, United States, ⁴Electrical Engineering and Computer Science, Northwestern University, Evanston, IL, United States

Cardiac Phase resolved Blood-Oxygen-Level-Dependent (CP-BOLD) MRI has been recently demonstrated for the identification of ischemic territories under resting conditions. Lack of accurate registration, necessary to provide pixel-to-pixel correspondences in the cardiac cycle, causes the majority of analysis to rely on segmental definitions of the myocardium and to use a few cardiac phases, decreasing the potential diagnostic power of the technique. To accelerate the development of methods that could potentially yield pixel-level characterization of ischemia, we propose and validate a synthetic CP-BOLD timeseries generator based on a composite dictionary model that learns to represent efficiently patterns under healthy and ischemic conditions.

Fanny Vaillant^1,2, Julie Magat^1,2, Jérôme Naulin^1,2, Virginie Loyer^1,2, Delphine Vieillot³, Véronique Arsac^1,2, Philippe Diolez^1,2, and Bruno Quesson^1,2
1IHU LIRYC, Pessac, France, ²Centre de Recherche Cardio-Thoracique de Bordeaux INSERM U1045, Université Bordeaux Segalen, France, ³Université Bordeaux Segalen, France

Magnetic Resonance (MR) imaging and spectroscopy allow non invasive characterization of cardiac structure, function and metabolism. We developed a new MR-compatible setup of ex vivo blood-perfusion of pig hearts with a working left atrium and ventricle. Using this setup, we succeeded to record parameters currently used in clinic, such as cardiac structure and dynamics. This ex vivo working heart model provides a new powerful tool to investigate cardiac mechanical and electrophysiological functions, structure and metabolism under well controlled conditions, and will be useful for a better understanding of cardiac function regulation and to assess efficiency of new diagnostic methods and therapies.

Martin Krämer¹, Karl-Heinz Herrmann¹, Judith Biermann¹, Sebastian Freiburger², Michael Schwarzer², and Jürgen R Reichenbach^1
1Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital - Friedrich Schiller University Jena, Jena, TH, Germany,²Department of Cardiothoracic Surgery, Jena University Hospital - Friedrich Schiller University Jena, TH, Germany

To perform cardiac cine imaging of a rat with a clinical whole-body 3T MRI system, a single slice was repeatedly acquired with radial readouts rotated using the golden-angle. The acquisition was interspersed with repetitive measurements of 1D navigator projections with a high frequency of 54 Hz. From the navigator data a correlation function was derived showing both respiratory and cardiac motion. Thresholding the correlation function to exclude respiratory motion retrospective cardiac cine-reconstruction was performed by using the cardiac signal from the navigator data. Spatial in-plane resolution of 0.21 x 0.21 mm³ was achieved in less than 10 minutes

Niranchana Manivannan¹, Kelly Banks², Anna Bratasz³, Debra Wheeler², Matthew Joseph², Ryan Huttinger², Ray E. Hershberger², and Kimerly A. Powell^3,4
1Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio, United States, ²Department of Internal Medicine, The Ohio State University, Ohio, United States, ³Small Animal Imaging Shared Resources, The Ohio State University, Ohio, United States, ⁴Department of Biomedical Informatics, The Ohio State University, Ohio, United States

Zebrafish’s ability to regenerate cardiac muscle makes it a good model for cardiovascular research. The goal of this study is to explore the efficacy of MRI in in-vivo cardiac imaging of adult zebrafish heart. Ex-vivo studies are carried out to study the structure of the heart in high resolution and to standardize the acquisition geometry to localize the heart. In in-vivo cine cardiac acquisition retrospective gating was used, as prospective ECG and respiratory gating was not possible. For the first time cardiac cine MRI in in-vivo zebrafish heart is acquired using retrospective sequence with navigator echo.

Ernst Suidgeest¹, Bigit Den Adel^1,2, José W.A. Van der Hoorn³, Rob E Poelmann⁴, and Louise Van der Weerd^1,5
1Radiology, LUMC, Leiden, Netherlands, ²Anatomy, LUMC, Netherlands, ³Metabolic Health Research, TNO, Leiden, Netherlands, ⁴Anatomy, LUMC, Leiden, Netherlands,⁵Human Genetics, LUMC, Netherlands

The objectives of this study were: 1. to establish whether rosiglitazone administration causes cardiac dysfunction in a mouse model. 2. to establish whether liposome-encapsulation reduces these side effects, if present, and 3. to investigate whether liposomal delivery of rosiglitazone preserves the therapeutic response compared to standard rosiglitazone. This study shows that MRI is a tool that can be used to assess the diverse aspects of metabolic syndrome. We showed that rosiglitazone at a standard clinical dose induces dilated cardiomyopathy and weight gain in the LDLr-/- mouse model. Micelle encapsulation of rosiglitazone significantly improves these unwanted side effects.

Geoffrey David Clarke¹, Jinqi Li², Cun Li³, and Peter W Nathanielsz^4
1Radiology, Univ Texas Health Science Center, San Antonio, TX, United States, ²Research Imaging Institute, Univ Texas Health Science Center, San Antonio, TX, United States, ³Obstetrics & Gynelocogy, Univ Texas Health Science Center, San Antonio, TX, United States, ⁴Obstetrics & Gynecology, Univ Texas Health Science Center, San Antonio, TX, United States

In this study cardiac MRI was used to measure LV cardiac function and 3D sphericity index (3DSI) in 8 male baboons subjected to intrauterine growth restriction to determine if subclinical functional impairment and myocardial remodeling associated with fetal programming occurs. LV 3DSI in growth restricted animals (N=4) was significantly different (p=0.03) compared to 3DSI in age-matched controls (N=5) suggesting myocardial remodeling does occur in these young animals.

Ulrich Flögel¹, Tomas Jelenik², Jörg Kotzka², Michael Roden^2,3, Jürgen Schrader¹, and Julia Szendroedi^2,3
1Molecular Cardiology, Heinrich Heine University, Düsseldorf, NRW, Germany, ²Institute for Clinical Diabetology, German Diabetes Center, Düsseldorf, NRW, Germany,³Department of Endocrinology & Diabetology & Metabolic Diseases, German Diabetes Center, Düsseldorf, NRW, Germany

The present study investigated how non-alcoholic fatty liver (NAFL) and insulin resistance relate to all-over body lipid homeostasis and cardiac function using transgenic mice with adipose tissue-specific overexpression of the transcription factor SREBP-1c. Analysis of body fat and heart function by ¹H MRI and localized ¹H MRS at 9.4 T revealed that in this model NAFL and insulin resistance associate with pronounced lipodystrophy and left ventricular hypertrophy. Although heart function remained still intact in this setting, long-term increased cardiac lipids and oxidative stress are likely to render the heart vulnerable for ischemic intolerance and impaired myocardial function with age.

Anirudh Mirakhur¹, Yoko Mikami², Khayam Khan², Andrew Howarth², and Naeem Merchant^1,2
1Diagnostic Imaging, University of Calgary, Calgary, Alberta, Canada, ²Stephenson Cardiovascular MR Centre, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada

Conventional short-tau-inversion-recovery (STIR) sequence for edema imaging in acute myocarditis is semi-quantitative at best and limited by technical factors. T2-mapping may open the way for a truly quantitativeapproach in assessing myocardial edema. Patients with acute myocarditis and healthy volunteerswere studied to assess the utility of T2 mapping in edema imaging. Based on our results, we conclude that myocardial T2 mapping can detect global edema and differentiate it from normal myocardium. In fact, T2 mapping may actually be more sensitive to focal edema than conventional STIR imaging.

Anirudh Mirakhur¹, Yoko Mikami², Khayam Khan², Andrew Howarth², and Naeem Merchant^1,2
1Diagnostic Imaging, University of Calgary, Calgary, Alberta, Canada, ²Stephenson Cardiovascular MR Centre, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada

Cardiovascular magnetic resonance (CMR) T2-mapping has potentialfor the detection and quantification of myocardial edema but the regional variability is unknown. The mean T2 relaxation time of normal myocardium has been reported around 52-55 milliseconds (ms), with most measurements performed in the mid-ventricle slice. Hence, we imaged healthy volunteers to assess for slice variability of myocardial T2 values. With the steady state free precession (SSFP)-based T2 mapping technique, normal global T2 values vary based on the slice selection. Therefore, the use of a single best normal global T2 value for the entire myocardium may not be accurate. Based on our data, the mid-ventricle is the most reliable slice for T2 quantification and also the most specific for detection of global edema.

Dan Zhu¹, Feng Huang², Feiyu Chen¹, Haikun Qi¹, Kui Ying³, Chun Yuan¹, and Huijun Chen^1
1Biomedical Engineering, Tsinghua University, Beijing, Beijing, China, ²Philips Healthcare, Florida, United States, ³Engineering Physics, Tsinghua University, Beijing, China

We compared the efficiency of k-t GRAPPA and k-t SPIRiT on cardiac DCE and CINE. By comparing the RMSEs and the intensity evolutions of DCE, as well as the RMSEs of CINE, we demonstrated that cardiac images reconstructed by both approaches from highly accelerated datasets are quite similar to the fully-sampled reference. However, k-t GRAPPA has lower RMSE and less computational cost, thus it is preferred to accelerate cardiac DCE and CINE imaging. Nevertheless, k-t SPIRiT could also be used when k-t GRAPPA is impossible such as reconstruction of randomly sampled k-space.

Sébastien Roujol¹, Warren J. Manning^1,2, and Reza Nezafat^1
1Department of Medicine, Beth Israel Deaconess Medical Center / Harvard Medical School, Boston, MA, United States, ²Department of Radiology, Beth Israel Deaconess Medical Center / Harvard Medical School, Boston, MA, United States

A respiratory navigator which tracks the diaphragmatic position is commonly used to correct the heart motion during free breathing acquisitions. However, the efficiency of this technique during prolonged breath-hold has not been fully investigated. In this study, we sought to assess the relation between the diaphragmatic motion and the heart motion during a prolonged breath hold performed with and without pre-oxygenation and hyperventilation.

Manivannan Jayapalan¹ and Bhargav Bhatt^1
1MR Software and Applications, GE Healthcare, Bangalore, Karnataka, India

Cardiac Magnetic Resonance Imaging (MRI) requires synchronization of electrocardiogram (ECG) signal with the acquisition. As the complete acquisition might not be acquired in one heart cycle, its successive acquisitions have to be accurately combined with the cardiac phase motion. Such requirements depends on a reliable detection of the R-wave of the ECG to guarantee that consecutive image data collections always start at the same point of the cardiac cycle. However the interaction of blood flow with static magnetic field, known as Magnetohydrodynamic (MHD) effect, introduces special kind of artifact in ECG which is known as MHD artifact or flow artifact. The effect of MHD is directly proportional the field strength and complicates the detection of R wave peak from ECG acquired during MR acquisition especially at higher field strengths. This work presents a method to identify R wave peaks which is contaminated with MHD artifact by smart thresholding using multilevel wavelet decomposition.

Yasuo Amano¹, Masaki Tachi¹, and Makoto Obara^2
1Nippon Medical School, Tokyo, Tokyo, Japan, ²Philips Asia Pacific, Tokyo, Japan

Blood T1 value is measured to calculate extracellular volume of the myocardium, which correlates with the severity of fibrosis. The effects of location of ROI, cardiac function, and flow on the blood T1 value are concerned. We compared the blood T1 value between the left ventricle and right ventricle or aorta at a 1.5 T and 3.0 T. The relationship between the blood T1 value and heart rate, ejection fraction, or jet induced by valvular regurgitation was assessed. Blood T1 value can be measured at both ventricle using postcontrast Look-Locker MRI without concern about cardiac function and intraventricular flow.

Suliman A. Barhoum¹, Zachary B. Rodgers¹, Michael C. Langham¹, Jeremy F. Magland¹, and Felix W. Wehrli^1
1Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States

Abnormal levels of CMRO2 are associated with a variety of disorders of the central nervous system. The critical step for CMRO2 quantification is estimation of venous oxygen saturation (SvO2). Here, we compare SvO2 in the superior sagittal sinus using three methods: susceptometry-based oximetry (SBO), projection-based T2 (PT2), and TRUST. Average SvO2 was 65±4% (SBO), 67±3% (PT2), and 61±4% (TRUST). There was good agreement among the three methods with slightly lower values found with TRUST (ANOVA, p<0.05). The main advantage of SBO over PT2 and TRUST is the simultaneous measurement of cerebral blood flow, which provides generally higher temporal resolution.

Matthias Korn¹, Titus Lanz¹, Carsten Kögler¹, Vicky Thornton², and Jürgen E. Schneider^2
1RAPID Biomedical GmbH, Rimpar, Germany, ²Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom

Cardiac imaging on mice needs both high performance gradient systems and optimized RF coils. The limited available space leads to either optimized gradient performance with a birdcage as Tx/Rx coil, which is the most commonly used design. Alternatively, larger gradient diameters allow for operating (large) Tx resonators and receive arrays. The aim of this work is to develop a Tx resonator and an Rx coil array, optimized for murine cardiac MRI and to be combined with a high-performance microscopy gradient system. Bench and MRI characterizations are provided, and a comparison with a quadrature driven Tx / Rx coil is performed, demonstrating superior performance of the coil-array for cardiac imaging.

Omid Forouzan¹, Evan Flink¹, Nick Thate¹, Andrew Hanske¹, Tongkeun Lee¹, Alejandro Roldan-Alzate^2,3, Christopher François³, Oliver Wieben^2,3, and Naomi Chesler^1
1Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States, ²Medical Physics, University of Wisconsin School of Medicine & Public Health, Madison, WI, United States, ³Radiology, University of Wisconsin School of Medicine & Public Health, Madison, WI, United States

The diagnosis of many cardiovascular diseases can benefit from imaging during a cardiac stress test. The purpose of this study was to develop a low-cost exercise device that could be used within the confines of an MRI bore during a cardiac MR scan and also provides measures of work. The device was designed to create exercise stress via a stepping motion by the subject in a supine position while minimizing unwanted chest movement and upper body translation. Our pilot testing results confirmed substantial increase in heart rate (+85%), cardiac output (+100%), mean aortic flow (+65%) and mean pulmonary artery flow (+%101) post-exercise.

Rieko Ishimura¹, Kenichi Yokoyama¹, Toshiya Kariyasu¹, Tatsuya Yoshioka², Isao Miyazaki², Shuhei Nitta³, Taichirou Shiodera³, Tomoyuki Takeguti³, Shigehide Kuhara⁴, Kuninori Kobayashi⁵, and Toshiaki Nitatori^1
1Department of Radiology, Kyorin University School of Medicine, Mitaka-shi, Tokyo, Japan, ²Department of Radiology, Kyorin University Hospital, Mitaka-shi, Tokyo, Japan,³Toshiba Corporation R&D Center, Tokyo, Japan, ⁴Toshiba Medical Systems Corporation, Tochigi, Japan, ⁵Department of Medical Radiological Technology, Faculty of Health Science, Kyorin University, Hachiouji-shi, Tokyo, Japan

Cardiac magnetic resonance imaging is also very useful for functional evaluation of the cardiac valves such as the aortic valve and pulmonary valve because it can be used to examine the valve openings and their shapes and to calculate flow rates based on the flow curves obtained using the phase contrast method. We investigated the usefulness of the automatic slice alignment in detecting the aortic valve planes. The knowledge-based automatic slice-alignment method described here permits the aortic valve reference planes, which are difficult to determine using the conventional method, to be detected quickly and easily.

Kang Wang¹, Mahdi Salmani Rahimi², Courtney K Morrison³, Christopher J Francois⁴, James H Holmes¹, and Frank R Korosec^3,4
1Global MR Applications and Workflow, GE Healthcare, Madison, WI, United States, ²Biomedical Engineering, University of Wisconsin-Madison, WI, United States, ³Medical Physics, University of Wisconsin-Madison, WI, United States, ⁴Radiology, University of Wisconsin-Madison, WI, United States

Conventional subtraction-based dynamic contrast-enhanced (DCE) MR Angiography (MRA) is susceptible to patient motion between the pre-contrast mask and the contrast phases. Recently, a 2-point Dixon based non-subtraction method for CE MRA has been proposed and improved motion robustness has been shown. However, it was demonstrated with single phase MRA; no temporal information was obtained. In this work, we combined 2-pt Dixon with fast dynamic imaging techniques and applied it for DCE MRA at 3T, eliminating the need for bolus timing or monitoring and gathering temporal information.

Lucilio Cordero-Grande¹, Javier Royuela-del-Val¹, Marcos Martín-Fernández¹, and Carlos Alberola-López^1
1Universidad de Valladolid, Valladolid, Castilla y León, Spain

This work presents the first application on real data of a method based in acquiring an overdetermined set of stripes for HARP-based reconstruction of the myocardial strain in SPAMM acquisitions and its combination with a method that makes use of the windowed Fourier Transform for the reconstruction. The experiments have shown, both quantitatively and visually, a more robust and precise reconstruction by introducing the aforementioned strategies within the HARP approach. The proposed methodology brings new opportunities in the design of acquisition sequences for strain imaging.

Jing Liu¹, Henrik Haraldsson², Li Feng³, and David Saloner^1
1University of California San Francisco, San Francisco, CA, United States, ²University of California San Francisco, CA, United States, ³New York University, NY, United States

In this study, we developed a free-breathing whole heart CINE IR sequence with continuous bSSFP data acquisition. Our preliminary results demonstrated that the proposed method has great potential for myocardium viability assessment.

Martijn Froeling^1,2, Gustav J. Strijkers², Aart J. Nederveen³, Steven A.J. Chamuleau⁴, and Peter R. Luijten^1
1Department of Radiology, University Medical Center, Utrecht, Netherlands, ²Biomedical NMR, Department of biomedical engineering, Eindhoven University of Technology, Eindhoven, Netherlands, ³Department of Radiology, Academic Medical Center, Amstredam, Netherlands, ⁴Department of Cardiology, Division Heart & Lung, University Medical Center, Utrecht, Netherlands

In this study we aimed to develop a SE-based cardiac diffusion MRI protocol that allows for whole heart DTI as well as intra-voxel coherent motion (IVIM) for perfusion assessment.

Ozan Sayin¹, Haris Saybasili², Henry Halperin³, M. Muz Zviman³, Mark Griswold⁴, Nicole Seiberlich⁵, and Daniel A. Herzka^1
1Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, United States, ²Siemens Healthcare USA, Inc., Chicago, IL, United States,³Department of Radiology, Johns Hopkins Hospital, Baltimore, MD, United States, ⁴Department of Radiology, Case Western Reserve University, Cleveland, OH, United States, ⁵Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States

Delayed contrast enhancement (DCE) imaging is a well-estabished MRI technique for the evaluation of myocardial tissue. Segmented k-space imaging, over multiple heartbeats, is preferred, as usually, a short quiescent phase in the cardiac cycle needs to be captured. Recently, DCE imaging has been carried out with cartesian single-shot sequences, enabling DCE imaging in single heartbeat. However, the quality of imaging that can replace the segmented k-space techniques have not yet been delivered, and thus, faster imaging which can also maintain image quality is of interest. In this work, we demonstrate the feasibility of DCE imaging with a highly-accelerated radial sequence.

Lukas Wissmann¹, William Paul Segars², and Sebastian Kozerke^1,3
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, ²Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, The Duke University Medical Center, Durham, North Carolina, United States, ³Division of Imaging Sciences & Biomedical Engineering, King's College London, London, United Kingdom

The development of novel acquisition and reconstruction techniques for MRI relies on realistic computer simulations. In case of cardiac applications, respiratory motion and cardiac contraction add to the simulation complexity. In this work, a framework for realistic numerical simulation of cardiac MRI is proposed. Anatomy and motion are provided by the XCAT phantom, which is based on the Visible Human project from the National Library of Medicine. The MR phantom is generated on top by simulating dynamic contrast, multiple receive coils, measurement noise and k-space trajectories. Showcase applications of image reconstructions from undersampled data are presented.

Andrew J Coristine^1,2 and Matthias Stuber^1,2
1Department of Radiology, University Hospital (CHUV) / University of Lausanne (UNIL), Lausanne, VD, Switzerland, ²CardioVascular Magnetic Resonance (CVMR) research centre, Centre for Biomedical Imaging (CIBM), Lausanne, VD, Switzerland

Two dimensional (2D) spatially selective radiofrequency (RF) pulses may be used to constrain the location from which an MR signal is obtained. This may lead to more time-efficient data collection by reducing the field of view (FoV) or may improve image quality by suppressing artefacts from outside the area of interest. Meanwhile, T₂-Preparation, or T₂-Prep, is a magnetization preparation scheme used to improve blood/myocardium contrast. We propose incorporating a "pencil-beam" 2D RF pulse into a T₂-Prep module, so as to produce a "2D T₂-Prep" that combines T₂-weighting with an intrinsic spatial selectivity. Numerical simulations, phantom validation, and in vivo results are presented.

Oisin Flanagan¹, Bruce Spottiswoode², Maria Carr³, Jeremy Collins³, Sven Zuehlsdorff², Jad Bou Ayache³, Marcos Botelho³, Xiaoming Bi⁴, Bradley D Allen³, Michael Markl³, Robert Edelman⁵, and James Carr^1
1Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States, ²Siemens Healthcare, USA, IL, United States, ³Northwestern University Feinberg School of Medicine, IL, United States, ⁴Siemens Healthcare, IL, United States, ⁵Northshore Healthsystem, IL, United States

This study investigates free breathing motion corrected (MOCO) phase sensitive inversion recovery imaging of delayed myocardial enhancement. It compares this technique to current standards methods of TrueFISP and TurboFLASH (TFL) sequences in 45 patients. PSIR MOCO is found to be equal or superior in image quality, diagnostic confidence and detection and qualitative evaluation of delayed myocardial enhancement in all cases.

Jesse I. Hamilton¹, Prabhakar Rajiah², Kestutis J. Barkauskas¹, Katherine L. Wright¹, Yun Jiang¹, Vikas Gulani², and Nicole Seiberlich^1
1Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States, ²Radiology, University Hospitals, Cleveland, OH, United States

Previous research has combined through-time radial GRAPPA with the golden angle trajectory to allow post-acquisition selection of the acceleration factor. In this work, a radiologist comparison of linear, golden angle, and self-calibrated golden angle radial GRAPPA was performed for real-time cardiac imaging. Golden angle radial GRAPPA received similar ratings in motion and anatomical visibility as linear radial GRAPPA up to R=8, despite slightly increased artifacts. No significant differences in scores were found between the two golden angle techniques. A preliminary radiologist review suggests that golden angle through-time radial GRAPPA may be preferable when the optimal temporal resolution is unknown a priori.

Tomoya Nakamura¹, Shuhei Shibukawa¹, Isao Muro¹, Nao Kajihara¹, Hiroaki Nishio¹, Tetsuo Ogino², Tetsu Niwa¹, and Yutaka Imai^1
1Tokai University Hospital, Isehara, Kanagawa, Japan, ²Philips Healthcare Asia Pacific, Tokyo, Japan

Cardiac diffusion-weighted imaging (DWI) often results in signal loss and poor visibility even though the cardiac triggering is used. The purpose of study is to assess the visualization of cardiac wall in cardiac triggered DWI using motion correction (MC) and accelerate motion correction (aMC). Muscle normalized signal intensity at aMC DWI is significantly higher than MC DWI and cardiac triggered DWI in each b-value of 200, 400, 600, and 800s/mm2. Visualization of cardiac wall is improved at aMC DWI even if the high b-value is used. DWI with aMC may enable to assess water molecular change in myocardial infarction.

Osama Abdullah¹, Stavros G Drakos², Abdallah Kfoury³, Joseph Stehlik³, Craig H. Selzman³, Bruce B Reid³, Nikolaos A Diakos², Kim Brunisholz³, Divya Ratan Verma³, Omar Wever-Pinzon³, Craig Myrick⁴, Dean Y Li², and Edward W Hsu^1
1Bioengineering, University of Utah, Salt Lake City, UT, United States, ²Molecular Medicine Program, University of Utah, UT, United States, ³UTAH Cardiac Transplant Program, UT, United States, ⁴Intermountain Donor Services, UT, United States

Myocardial diffuse fibrosis has been linked to arrhythmias and sudden cardiac death. Although diffusion tensor imaging (DTI) is increasingly used to characterize cardiac diseases, quantitative correlation between DTI scalar metrics and diffuse fibrosis remains lacking. In this study, DTI parameters obtained on heart specimens from idiopathic dilated cardiomyopathy patients and normal donors were correlated to histological collagen content measurements. Results indicate that diffuse fibrosis is significantly correlated with water diffusivity, and inversely correlated with diffusion anisotropy. Computational analysis shows that the behaviors of the DTI parameters are well explained by compartmental exchange between myocardial and collagenous tissues.

Xiaodong Chen^1,2, Zuoquan Zhang³, Jinglian Zhong⁴, Qihua Yang⁴, Ziliang Cheng⁴, and Biling Liang^4
1Sun Yat-Sen Memorial Hospital, Guang Zhou, Guang Dong, China, ²Guangdong Medical College, Guangdong, China, ³The Fifth Affiliated Hospital of Sun Yat-Sen University, Guangdong, China, ⁴Sun Yat-Sen Memorial Hospital, Guangdong, China

To study the optimal initial age of cardiac iron screening with MRI T2* in patients with thalassemia major(TM). We retrospectively reviewed of cardiac T2* assessments from 102 TM patients between the ages of 3 to 32 years. We found that no patient under 5 years old showed detectable cardiac iron. Cardiac iron level correlated weakly with ferritin and liver iron, but not with patient age. So we drew a conclusion that cardiac iron overload can occur in young patients and assessment of cardiac iron with MRI should be initiated as early as 5 years of age, even in asymptomatic patients.

Venkat Ramanan¹, Mohammad Zia², Idan Roifman¹, Bradley H Strauss¹, Kim Connelly³, Graham A Wright^1,4, and Nilesh Ghugre^1,4
1Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada, ²Toronto East General Hospital, Toronto, Ontario, Canada, ³St Michaels Hospital, Toronto, Ontario, Canada, ⁴Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada

Prior studies have shown that extracellular matrix alterations can occur both in infarcted and remote myocardium. However, the relationship between the extracellular volume (ECV) measurements and the severity of infarct has not been explored. Here, we investigate the impact of microvascular obstruction (MVO) on ECV alterations using MOLLI based T1-mapping. We scanned patients post-MI at 48 hour and at 3 weeks. We found that for patients with MVO, ECV was higher significantly in both infarcted and remote tissue at 3 weeks. These findings also suggest that early changes in the remote myocardium may potentially be indicative of long-term adverse remodeling post-AMI.

Neville D Gai¹, Fabio Raman¹, and David Bluemke^1,2
1Radiology & Imaging Sciences, NIH, Bethesda, Maryland, United States, ²NIBIB, Bethesda, Maryland, United States

Post-contrast myocardial T1 values and associated measures such as extracellular space (ECV) can show variation due to the acquisition scheme. In particular variation due to heart rate results in biased values for T1. We show that this bias can exhibit a systematic relationship with heart rate. An ex post facto solution is proposed which would allow for comparison of T1 values between subjects with varying heart rates. Results of a phantom study are presented to illustrate our correction method.

Sofia Kvernby^1,2, Marcel Warntjes^1,2, Carl-Johan Carlhäll^1,2, Jan Engvall^1,2, and Tino Ebbers^1,2
1Institution of Medical and Health Sciences, Linköping, Östergötland, Sweden, ²Center for Medical Image Science and Visualisation, Linköping, Östergötland, Sweden

Recently, a novel method has been developed for myocardial 3D quantification of both T1 and T2 with whole coverage of the left ventricular myocardium within one breath hold (3D-QALAS). In this work we validate 3D-QALAS in-vivo by comparison with MOLLI-sequence for myocardial T1-mapping and multi-echo for myocardial T2-mapping. Relaxation times measurements obtained with 3D-QALAS correspond well with data from existing 2D mapping methods and allows a fast acquisition that provides information about both T1 and T2, making the method clinically applicable to a broader spectrum of diseases.

Ria Mazumder¹, Bradley D. Clymer¹, Richard D. White², Anthony J. Romano³, and Arunark Kolipaka^2
1Department of Electrical and Computer Engineering, The Ohio State University, Columbus, OH, United States, ²Department of Radiology, The Ohio State University, Columbus, OH, United States, ³Department of The Navy, Naval Research Laboratory, Washington, DC, United States

Myocardial stiffness (MS) is elevated in heart failure with preserved ejection fraction (HFPEF) wherein the ejection fraction (EF) of the left ventricle (LV) stays normal. Hence, current diagnostic tools that measure EF of the LV inhibit diagnosis of HFPEF. Therefore, there is a need to develop a clinical tool to estimate myocardial stiffness in order to characterize the pathophysiological conditions associated with the disease. In this study, we measure myocardial stiffness in a porcine model with varying LV pressure, using waveguide magnetic resonance elastography to estimate anisotropic stiffness of the LV myocardium.

Shams Rashid¹, Stanislas Rapacchi¹, Roderick Tung², Kalyanam Shivkumar², Daniel Ennis¹, J. Paul Finn¹, and Peng Hu^1
1Department of Radiological Sciences, University of California, Los Angeles, Los Angeles, CA, United States, ²Cardiac Arrhythmia Center, University of California, Los Angeles, Los Angeles, CA, United States

We have modified a 3D IR-FLASH sequence for LGE cardiac MRI of patients with implanted cardiac devices. We show that a conventional 3D FLASH sequence produces artifacts which do not appear in corresponding 2D wideband LGE images. We optimizied the 3D LGE sequence by implementing a wideband IR pulse and by increasing the bandwidth of the excitation pulse. We show that this modified 3D wideband LGE sequence is very promising in removing aforementioned artifacts and produce high resolution images in patients with cardiac devices.

Jiaxin Shao¹, Yutaka Natsuaki², Bruce Spottiswoode², Kim-Lien Nguyen^1,3, and Peng Hu^1,4
1Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, United States, ²Siemens Healthcare USA, Inc., IL, United States, ³Division of Cardiology, David Geffen School of Medicine, University of California, Los Angeles, CA, United States, ⁴Biomedical Physics Inter-Departmental Graduate Program, University of California, Los Angeles, CA, United States

We propose a new T1 mapping method, Instantaneous Signal Loss simulation (InSiL), for the MOLLI sequence. InSiL was evaluated against standard MOLLI using phantom study, and in 10 healthy volunteers at 1.5T. Phantom results show that the maximum absolute error by InSiL is less than 12ms, while that by MOLLI is more than 300ms for T1 values around 223ms-1641ms. InSiL reduced MOLLI T1 absolute error from 197ms to 4ms on average for T1>1000ms, HR≥80bpm. The native myocardial T1 values by InSiL were greater than that by MOLLI by 238.0±9.0ms (1166.0±23.1ms vs. 928.1±21.8ms) at an average heart rate of 63.7±11.2bpm.

Adrienne E Campbell-Washburn¹, Rachel K Dongworth², Thomas A Roberts^3,4, Anthony N Price⁵, David L Thomas⁶, Roger J Ordidge⁷, Derek M Yellon², Derek J Hausenloy², and Mark F Lythgoe^3
1Division of Intramural Research, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, United States, ²The Hatter Cardiovascular Institute, University College London, London, United Kingdom, ³Centre for Advanced Biomedical Imaging, University College London, London, United Kingdom, ⁴Centre for Mathematics and Physics in the Life Sciences & Experimental Biology, University College London, London, United Kingdom, ⁵Division of Imaging Sciences and Biomedical Engineering, St Thomas' Hospital, King's College London, London, United Kingdom, ⁶Department of Brain Repair and Rehabilitation, Institute of Neurology, University College London, London, United Kingdom, ⁷Centre for Neuroscience, University of Melbourne, Melbourne, Australia

In order to assess myocardial salvage when evaluating new therapeutic strategies for myocardial infarction, we require the measurement of both infarct size and area-at-risk. In this study, a multi-parametric analysis of infarct (late gadolinium enhancement), oedema (T2 mapping) and perfusion (arterial spin labeling, ASL) is presented for ischemia-reperfusion injury in a mouse model. Late enhancement and T2 mapping correspond well to infarct size and area-at-risk (respectively), as expected. Interestingly, multi-slice ASL shows perfusion deficits, which correspond to area-at-risk, despite reperfusion. This platform will be a useful tool for in vivo investigation of AAR pathophysiology following ischemia-reperfusion injury.

Christopher Nguyen^1,2, Zhaoyang Fan¹, Behzad Sharif¹, Yi He³, Tianjing Zhang⁴, Jing An⁴, Xiaoming Bi⁵, Minjie Lu⁶, Rohan Dharmakumar¹, Daniel S Berman¹, Shihua Zhao⁶, and Debiao Li^1,2
1Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States, ²Bioengineering, University of California Los Angeles, Los Angeles, CA, United States, ³Radiology, Anzhen Hospital, Beijing, China, ⁴MR Collaborations NE Asia, Siemens Healthcare, Beijing, China, ⁵MR R&D, Siemens Healthcare, Los Angeles, CA, United States, ⁶State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, Beijing, China

Myocardial tissue microstructure exhibits fiber disarray that manifests in a stark increase (50-100% change for 20-70% fibrosis) in trace apparent diffusion coefficient (trADC). To ensure sensitivity to this change, we developed a free-breathing bulk motion compensated diffusion-prepared segmented balanced steady-state free precession technique capable of 3D high resolution in vivo cardiac diffusion-weighted MRI. In healthy volunteers, the proposed technique yielded LV trADC values consistent with previously reported values. Preliminary application in HCM patients revealed 40% increase in trADC in corresponding LGE-identified fibrotic regions. The proposed diffusion technique may potentially allow for non-contrast imaging of myocardial fibrosis in HCM patients.

Verena Hoerr¹, Nina Nagelmann¹, Janine Ring¹, Arno Nauerth², Michael Kuhlmann³, and Cornelius Faber^1
1Department of Clinical Radiology, University Hospital Muenster, Muenster, Germany, ²Bruker BioSpin MRI GmbH, Ettlingen, Germany, ³European Institute for Molecular Imaging (EIMI), Muenster, Germany

In our study we have developed a novel MRI tool kit for the detection of infective endocarditis in mice. It allows for early diagnosis and detailed characterization of morphological and functional changes of infected cardiac valves. By Reflection Point analysis the valvular structures in self-gated cine UTE images are highlighted by rescaling the image intensities according to the distance to the Reflection Point. This corrects for partial volume effects and signal gradients caused by surface coils and allows for an accurate assessment of the cardiac valves during the full cardiac cycle with respect to valve thickening and bacterial vegetations.

Christian Torben Stoeck¹, Aleksandra Kalinowska², Constantin von Deuster^1,3, Jack Harmer³, and Sebastian Kozerke^1,3
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, ²Department of Mechanical and Biomedical Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States, ³Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom

Cardiac Diffusion Tensor imaging using the Stimulated Echo Acquisition Mode suffers from inherent myocardial strain effects as diffusion is encoded across 2 R-R intervals. Based on knowledge of the time course of myocardial stretch patterns, diffusion tensor data can be corrected for strain errors. In this work we present a pipeline for deriving stretch tensor fields from three-dimensional myocardial tagging images to correct dual heart phase cardiac DTI data. Upon strain correction, systolic and diastolic fiber architecture acquired in the in-vivo human heart are compared.

Samad Javid¹, David Lake¹, Shivaram Poigai¹, Arvin Arani¹, Armando Manduca¹, Kiaran McGee¹, Richard Ehman¹, Dan Dragomir-Daescu¹, and Philip Araoz^1
1Mayo Clinic, Rochester, MN, United States

Cardiac MRE may be able to measure the regional myocardial shear stiffness. We used Finite Element (FE) technique to simulate a noise-free displacement filed in the myocardial wall of a polymeric heart phantom. MRI was used to measure the displacement field in the heart phantom. DI and LFE were then used to estimate the shear modulus in the phantom using the FE simulated and MR measured displacement data. Both inversion methods underestimated the shear modulus in the myocardial wall. The results showed that in thin walled structures, DI and LFE give better estimations of shear modulus at higher frequencies.

Sébastien Roujol¹, Sebastian Weingärtner^1,2, Murilo Foppa¹, Kelvin Chow³, Keigo Kawaji¹, Kraig V Kissinger¹, Beth Goddu¹, Sophie Berg¹, Peter kellman⁴, Warren J. Manning^1,5, Richard B. Thompson³, and Reza Nezafat^1
1Department of Medicine, Beth Israel Deaconess Medical Center / Harvard Medical School, Boston, MA, United States, ²Computer Assisted Clinical Medicine, University Medical Center Mannheim, Heidelberg University, Mannheim, Germany, ³Department of Biomedical Engineering, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada, ⁴National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, United States, ⁵Department of Radiology, Beth Israel Deaconess Medical Center / Harvard Medical School, Boston, MA, United States

Quantitative myocardial T₁ mapping provides in-vivo tissue characterization for assessment of cardiomyopathies. The extracellular volume fraction (ECV) can be calculated from pre and post-contrast T₁ maps and shows promise for the detection of diffuse myocardial fibrosis. Several techniques have been recently proposed for myocardial T₁mapping. However, no comprehensive comparison has been performed across these methods. In this study, we sought to analyze T₁ and ECV measurements in term of accuracy, precision and reproducibility from four T1 mapping techniques: Modified Look-Locker Inversion Recovery (MOLLI), Shortened MOLLI (ShMOLLI), Saturation recovery single-shot acquisition (SASHA), and SAturation Pulse Prepared Heart rate independent Inversion-REcovery sequence (SAPPHIRE).

Andrew James Swift¹, Smitha Rajaram², Dave Capener³, Judith Hurdman⁴, Robin Condliffe⁴, Charlie Elliot⁴, Jim Wild³, and David G Kiely^4
1University of Sheffield, Sheffield, S.Yorkshire, United Kingdom, ²Radiology Department, Sheffield Teaching Hospitals NHS Trust, S.Yorkshire, United Kingdom, ³University of Sheffield, S.Yorkshire, United Kingdom, ⁴Sheffield Pulmonary Vascular Disease Unit, Sheffield Teaching Hospitals NHS Trust, S.Yorkshire, United Kingdom

Late gadolinium enhanced imaging allows the assessment of changes in the extra cellular compartment of myocardial tissue related to pathophysiological processes of oedema and fibrosis. This study shows that LGE of the interventricular septum in patients with pulmonary hypertension indicates a clinical phenotype with patients having higher right ventricular volume and worse outcome.

Eric P. Aliotta^1,2, Marmar Vaseghi³, Kalyanam Shivkumar³, and Daniel B. Ennis^1,2
1Biomedical Physics IDP, University of California, Los Angeles, CA, United States, ²Department of Radiological Sciences, University of California, Los Angeles, CA, United States, ³Cardiac Arrhythmia Center & EP Programs, University of California, Los Angeles, CA, United States

Diffusion Tensor MRI (DT-MRI) is currently used to study cardiac microstructure, but several limitations hinder its ability to measure secondary and tertiary directions of diffusion, which are important to our understanding of cardiac myolaminar organization. Generalized Q-sampling MRI (GQ-MRI) overcomes these limitations. We compared primary, secondary, and tertiary directions of diffusion between DT-MRI and GQ-MRI in ex vivo infarcted porcine hearts and showed that the primary directions of diffusion are in excellent agreement (7.1° median difference), but that the secondary and tertiary directions differ by 24.8° and 34.2°. This disagreement indicates that DT-MRI may not accurately characterize myolaminar sheet orientation.

Valentina Mazzoli¹, Martijn Froeling^1,2, Aart J Nederveen³, Klaas Nicolay¹, and Gustav J Strijkers^1
1Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands, ²Department of Radiology, University Medical Center, Utrecht, Netherlands, ³Department of Radiology, Academic Medical Center, Amsterdam, Netherlands

Conventional Diffusion Tensor Imaging (DTI) has been extensively applied to study myocardial fiber architecture. However, due to the inability in identifying crossing fibers and low sensitivity on microstructural characteristics, DTI fails to provide a detailed picture of the (micro)structure of cardiac muscle. We therefore proposed the use of DKI and CSD to the study of the ex-vivo porcine heart. DKI showed a better sensitivity than normal DTI to regional microstructural differences across the wall, and CSD was correctly able to identify crossing myoloaminar structures. These techniques could be useful for reaching a deeper knowledge of cardiac structure and function.

Patrick Winter¹, Thomas Kampf¹, Xavier Helluy¹, Fabian Tobias Gutjahr¹, Cord Bastian Meyer¹, Eberhard Rommel¹, Wolfgang Rudolf Bauer², Peter Michael Jakob¹, and Volker Herold^1
1University of Würzburg, Würzburg, Bavaria, Germany, ²Universitätsklinik Würzburg, Würzburg, Bavaria, Germany

A new workflow was developed for the extraction of a radial self-gating signal in mice from an Inversion Recovery Snapshot FLASH sequence. The new method almost completely removes the T1 relaxation background and the phase shift caused by the inversion of blood magnetization at the zero-crossing point. A comparison of the self-gating signal with an additional monitored ECG signal showed small deviations for the trigger points extracted from the radial data even at the beginning of the inversion. Both the k-space signal and the reference were used for retrospective global and slice-selective T1 mapping and yield matching T1 values.

Christopher Lee Welsh^1,2, Edward VR DiBella², and Edward W Hsu^1
1Department of Bioengineering, University of Utah, Salt Lake City, UT, United States, ²Radiology, UCAIR, University of Utah, Salt Lake City, UT, United States

Diffusion tensor imaging of the beating heart is technically challenging and remains elusive in some small animals due to the speed and scale of motion compared to the available gradient hardware performance. The current study performed a systematic analysis of the effects of cardiac motion on diffusion encoding and designed means to minimize them via higher-order motion compensation. Experimental testing showed that nulling of gradient moments associated with up to acceleration offered the best tradeoff among diffusion encoding level, motion artifact reduction, and image SNR. These efforts led to the first successful myocardial fiber orientation maps obtained in live rats.

Till Huelnhagen¹, Andreas Pohlmann¹, Fabian Hezel¹, Eva Peper¹, Min-Chi Ku¹, and Thoralf Niendorf^1,2
1Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine (MDC), Berlin, Germany, ²Experimental and Clinical Research Center, a joint cooperation between the Charite Medical Faculty and the Max Delbrueck Center, Berlin, Germany

Myocardial microstructure is pivotal for cardiac function and provides important information about (patho)physiological conditions of the heart. Ex vivo histology and diffusion weighted imaging (DWI) are commonly used to assess myocardial tissue microstructure, but in vivo DWI of the heart remains challenging due to cardiac and respiratory motion. Encouraged by the recent progress in susceptibility weighted MRI we have investigated the feasibility of high resolution quantitative susceptibility mapping (QSM) for assessment of myocardial microstructure in the ex vivo rat heart at 9.4 T. Results suggest that QSM might be a useful tool for examination of myocardial microstructure.

Shivaram Poigai Arunachalam¹, Arvin Arani¹, Roger Grimm¹, Kiaran McGee², and Philip Araoz^1
1Radiology, Mayo Clinic, Rochester, MN, United States, ²Medical Physics, Mayo Clinic, Rochester, MN, United States

Characterizing myocardial tissue is of great importance in diagnosing and treating various diseases of the heart such as diastolic heart failure etc. Cardiac MR Elastography is an MRI based phase contrast technique that applies shear waves to the myocardium and estimates its stiffness. Robust estimates for myocardial stiffness demands high SNR wave images obtained in reasonable amount of time. This study focuses on investigating the optimal MRE driver location (apex, sternum and lateral side) and patient position (supine vs. prone) that can yield high amplitude shear waves for accurate myocardial stiffness estimation for diagnosing heart diseases.

Maythem Saeed¹, Robert Jablonowki¹, Madhav Agrawal¹, Steve W. Hetts¹, and Mark W. Wilson^1
1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, United States

Contiguous, but not patchy, myocardial infarction has been measured using 3D and 2D DE-MRI and validated using histochemical and histopathological staining. The purpose of this study was to: 1) measure patchy and contiguous infarction size using delayed enhanced 3D inversion recovery (IR) gradient echo (GRE) in beating and non-beating swine hearts and 2) compare the 3D measurements against 2D-IR GRE, histochemical and histopathological staining. Myocardial infarction measured on 3D MRI correlated well and in a good agreement with microscopic data. This imaging sequence has the potential to measure diffuse and large acute myocardial infarction and has minimal motion artifacts.

Shams Rashid¹, Adam Plotnik¹, Harold Litt², Yuchi Han^3,4, Stanislas Rapacchi¹, Roderick H Tung⁵, Kalyanam Shivkumar⁵, J. Paul Finn^1,6, and Peng Hu^1,6
1Department of Radiological Sciences, University of California, Los Angeles, Los Angeles, CA, United States, ²Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States, ³Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States, ⁴Penn Cardiovascular Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States, ⁵Cardiac Arrhythmia Center, University of California, Los Angeles, Los Angeles, CA, United States, ⁶Biomedical Physics Inter-Departmental Graduate Program, University of California, Los Angeles, Los Angeles, CA, United States

We developed a wideband-IR LGE technique to eliminate the hyper-intensity artifacts seen in LGE MRI of patients with implantable cardioverter defibrillators (ICDs). This technique was implemented at two institutions and evaluated on 25 patients. The new wideband LGE sequence was compared with the conventional (narrowband-IR) LGE sequence by quantifying hyper-intensity artifacts. While hyper-intensity artifacts were prominent in the conventional LGE images, artifacts were completely eliminated in the wideband LGE images. The wideband LGE technique may enable widespread utility of LGE MRI in patients with implanted cardiac devices, in whom LGE MRI otherwise could not be used for diagnosis.

Irvin Teh¹, Dunja Aksentijevic^1,2, and Jurgen E Schneider^1
1Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom, ²Cardiovascular Division, The Rayne Institute, King's College London, London, United Kingdom

Diffusion spectrum imaging (DSI) enables the measurement of the diffusion probability density function in a model-free manner. It provides access to a number of parameters that may serve as sensitive markers in cardiac disease such as ischemia and hypertrophy. However, it has been shown in simulations and phantoms that some of these parameters are highly sensitive to the acquisition protocol. We investigated four DSI-derived parameters for assessing myocardial structure, including the mean squared length, generalised fractional anisotropy, probability at zero displacement and mean kurtosis and their sensitivity to b-value and signal-to-noise ratio via prospective sampling of multiple DSI datasets.

Laurence Jackson¹, Angela d'Esposito¹, Bernard Siow¹, Daniel J Stuckey¹, and Mark F Lythgoe^1
1Centre for Advanced Biomedical Imaging, University College London, London, London, United Kingdom

A technique is established for imaging myocyte orientation in the myocardium using Diffusion Tensor MRI, from this orientation information it is possible to determine the myofibre architecture of the heart. The aim of this study is to combine this fibre structure information with optical projection tomography data, allowing the distribution of fluorescent labelled molecules to be imaged in 3D. Optical imaging techniques have the ability to quantify gene expression in tissues by their fluorescent response. A proposed use for this multi-modal technique is quantification of the angiogenic factors associated with the myofibre remodelling following myocardial infarction.

Katharina Fuchs¹, Fabian Hezel¹, Celal Oezerdem¹, Lukas Winter¹, and Thoralf Niendorf^1,2
1Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany, ²Experimental and Clinical Resarch Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center, Berlin, Germany

T₂^* mapping is an emerging technique holding the promise to provide advancement in myocardial tissue characterization. The linear relationship between magnetic field strength and microscopic susceptibility renders it conceptually appealing to pursue myocardial T₂^* mapping at ultrahigh fields. Gradient echo based techniques show pronounced propensity to susceptibility artifacts due to the required long echo times. This work investigates the feasibility of RARE based T₂^* mapping at 7 T using bowtie antennas to offset RF power deposition and RF non-uniformity constraints. Myocardial T₂^* mapping at 7 T is feasible and provides susceptibility weighted images and T₂^*maps free of distortion.

Masaki Tachi¹, Yasuo Amano¹, Minako Takeda¹, Yoshio Matsumura¹, Masashi Ogawa¹, Makoto Obara², Kuniya Asai³, Keisuke Inui³, and Shinichiro Kumita^1
1Radiology, Nippon Medical School, Bunkyo-ku, Tokyo, Japan, ²Philips Asia Pacific, Tokyo, Japan, ³Cardiology, Nippon Medical School, Bunkyo-ku, Tokyo, Japan

The objective of this study was to assess correlation between cardiac functional parameters and some types of myocardial T1 values and extracellular volume fraction (ECV), given by MOLLI, in dilated cardiomyopathy (DCM). Myocardial T1 value before contrast showed good correlations with several cardiac functional parameters. ECV derived from 10 minutes after contrast also showed good correlations. The interventricular septum was the appropriate region for assessing the T1 and ECV related to cardiac functional parameters in DCM.

Sébastien Roujol¹, Murilo Foppa¹, Sebastian Weingärtner^1,2, Warren J. Manning^1,3, and Reza Nezafat^1
1Department of Medicine, Beth Israel Deaconess Medical Center / Harvard Medical School, Boston, MA, United States, ²Computer Assisted Clinical Medicine, University Medical Center Mannheim, Heidelberg University, Mannheim, Germany, ³Department of Radiology, Beth Israel Deaconess Medical Center / Harvard Medical School, Boston, MA, United States

Quantitative myocardial T₁ mapping is commonly performed using a breath-hold ECG-triggered acquisition. Despite breath-hold instructions, motion is observed in ~50% of patients due to diaphragmatic drift and the patient’s limited breath-holding capability. Registration of each T₁-weighted image can be performed to reduce motion artifacts in T₁ maps but remains challenging due to the high intensity variations among T₁ weighted images. In this study we propose a novel non-rigid motion correction approach for improved T₁ mapping.

Martin A Janich¹, Jeffrey A Stainsby², Piero Ghedin³, Glenn S Slavin⁴, David Stanley⁵, Maggie Fung⁶, Oleg Shubayev⁷, Steven D Wolff⁷, and Anja Brau^3
1GE Global Research, Garching, Germany, ²GE Healthcare, Toronto, ON, Canada, ³GE Healthcare, Garching, Germany, ⁴GE Healthcare, Bethesda, MD, United States, ⁵GE Healthcare, Rochester, MN, United States, ⁶GE Healthcare, New York, NY, United States, ⁷Advanced Cardiovascular Imaging, New York, NY, United States

Late gadolinium enhancement (LGE) pulse sequence was modified to suppress fat signal. The implementation was designed to be robust against variations of heart rate by adapting timing of RF pulses to the current heart rate.

Shigehide Kuhara¹, Hironobu Ishikawa², Takashi Kanazawa², Shinya Seino², Shuhei Bannae¹, Hideaki Takasumi², Takanori Sato², and Takeshi Yusa^2
1Toshiba Medical Systems Corporation, Otawara-shi, Tochigi, Japan, ²Department of Radiology, Fukushima Medical University Hospital, Fukushima, Japan

We have developed a new method for determining the optimal TI value, called Polarity-Corrected (PC) TI Prep tool, based on the IR + 2D segmented FE technique. In this new method, the acquired data is corrected to match the data points after magnetization recovery by phase correction, and curve fitting with RR correction is then applied to determine the optimal TI value analytically. This method can also be used to measure the T1 values together with the optimal TI value, which suggests that it should be suitable for use as a T1 mapping tool in commercially available MRI scanners.

Pieternel van der Tol¹, Qian Tao¹, Rob J. van der Geest¹, and Hildo J. Lamb^1
1Department of Radiology, Leiden University Medical Center, Leiden, Netherlands

Extracellular volume fraction (ECV) of the myocardium can provide a quantitative measure for cardiomyopathies. In our research we propose the use of a free breathing T1-mapping method combined with dedicated post processing to acquire whole heart ECV maps based on native and post contrast T1-maps. We compared this method to the MOLLI T1-mapping method, and found a non-significant bias towards higher ECV for our method. The proposed method facilitates whole heart ECV mapping in the same amount of time as MOLLI, however it circumvents the need for multiple breath holds, making it more suitable for patients.

David A Broadbent^1,2, David M Higgins³, Vanessa Ferreira⁴, Alexander Liu⁴, Claudia Marini⁴, Christopher M Kramer⁵, Sven Plein¹, Stefan Neubauer^4,6, and Stefan K Piechnik^4
1Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, United Kingdom, ²Division of Medical Physics, University of Leeds, Leeds, United Kingdom,³Philips Healthcare, Guildford, United Kingdom, ⁴Centre for Clinical Magnetic Resonance Research, University of Oxford, Oxford, United Kingdom, ⁵Department of Medicine and Radiology, University of Virginia Health System, Charlottesville, Virginia, United States, ⁶Division of Cardiovascular Medicine, University of Oxford, Oxford, United Kingdom

In this study we performed an inter-site, inter-vendor comparison of myocardial T1 mapping in preparation for a large multi-centre study. Native myocardial T1 measurements were compared in five healthy volunteers using different MOLLI variants on two 3T scanners (one Siemens, one Philips) from different vendors at different UK centres. Some bias (~2%) was observed between one variant and the other two, although this variant was only tested at one site and requires further validation. Bias between the other variants and the vendors/sites was small, providing support for the use of these techniques in multi-centre studies.

Daniel Gensler^1,2, Philipp Mörchel², Peter M. Jakob^2,3, and Peter Nordbeck^1
1Department of Internal Medicine I - Cardiology, University Hospital Würzburg, Würzburg, Bavaria, Germany, ²Research Center Magnetic-Resonance-Bavaria, Würzburg, Bavaria, Germany, ³Experimental Physics 5, University of Würzburg, Würzburg, Bavaria, Germany

Late gadolinium enhanced (LGE) cardiovascular magnetic resonance (CMR) is the clinical gold-standard for the visualization of myocardial viability and impairment due to various diseases such as myocardial infarction. However, LGE-CMR has only very limited capabilities for quantitative measurements of slight abnormalities in the myocardium, or the differentiation between different myocardial damage. In the current work an ultra-fast radial T1-mapping sequence was developed and tested for its potential in quantification of the myocardial extracellular volume (ECV) in patients with myocardial infarction. The obtained ECV-maps in this preliminary subset of patients allowed for a differentiation between chronic and acute myocardial infarction areas.

Kosuke Morita^1,2, Daisuke Utsunomiya³, Seitaro Oda³, Tomohiro Namimoto², Masanori Komi¹, Mika Kitajima², Toshinori Hirai², Masahiro Hashida¹, and Yasuyuki Yamashita^2
1Radiology, Kumamoto university hospital, Kumamoto, Kumamoto, Japan, ²Diagnostic Radiology, Faculty of Life Sciences, Kumamoto university, Kumamoto, Kumamoto, Japan, ³Diagnostic Imaging Analysis, Faculty of Life Sciences, Kumamoto university, Kumamoto, Japan

The purpose of our study was to optimize the myocardial T1 mapping technique using a composite RF pulse, which is widely available in clinical practice. We evaluated the effect of the composite RF pulse on T1 maps using Saturation Recovery method with composite RF pulse by phantom and human studies. We also evaluated T1 value of cardiac amyloidosis patients. Our experiments showed that a T1 mapping with SR method using composite RF pulse provides more accurate quantification of T1 values. It may facilitate the detection of even the smallest fibrosis with no contrast agent in cardiomyopathy patients.

Maelene Lohezic¹, Remi Peyronnet², Craig Lygate¹, Peter Kohl^2,3, and Jurgen E Schneider^1
1Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom, ²National Heart and Lung Institute, Imperial College London, London, United Kingdom, ³Department of Computer Science, University of Oxford, Oxford, United Kingdom

Myocardial microstructure underpins cardiac function in health and disease, and can be assessed by diffusion tensor MRI (DTI) in a non-destructive manner and throughout the cardiac cycle. Here, we investigate changes in DTI parameters in the live, chronically infarcted, rat heart in multiple mechanical states. In the remote area, the apparent diffusion coefficient increased, while the fractional anisotropy was similar to healthy control, in both slack and contracture states. Also, remodeling translated into an increase in the proportion of right-handed fibers in the remote area while disarray was observed in the infarct zone.

Kelvin Chow¹ and Richard B Thompson^1
1Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada

The MOLLI sequence is commonly used for in-vivo cardiac T₁ mapping but is known to have systematic errors as a function of heart rate, flip angle, T₁, and T₂. We hypothesize that the apparent MOLLI relaxation rate (R₁^*) can be expressed as a time weighted average (TWA) of the driven relaxation rate during bSSFP readouts (R₁^') and the true relaxation rate (R₁) between readouts. An algebraic expression for R₁^* is presented and validated through Bloch equation simulations and phantom experiments. The TWA model analytically describes the effects of many of MOLLI’s sources of error and provides insight into their interaction.

Sebastian Weingärtner^1,2, Mehmet Akcakaya¹, Sebastien Roujol¹, Warren J Manning^1,3, and Reza Nezafat^1
1Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States, ²Computer Assisted Clinical Medicine, University Medical Center Mannheim, Heidelberg University, Mannheim, Germany, ³Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States

We propose a 2D SAPPHIRE sequence for combined LGE/T1 mapping enabling simultaneous evaluation of myocardial scar and fibrosis in a single breath-hold exam, by the use of combined saturation/inversion recovery magnetization preparation.

Fabian Tobias Gutjahr¹, Thomas Kampf¹, Xavier Helluy¹, Patrick Winter², Christian Herbert Ziener³, Peter Michael Jakob^1,4, and Wolfgang Rudolf Bauer^5
1Experimental Physics 5, University of Wuerzburg, Wuerzburg, Bavaria, Germany, ²Experimental Physics 5, University of Wuerzburg, Bavaria, Germany, ³DKFZ, Heidelberg, Baden Wuerttemberg, Germany, ⁴Magnetic Resonance Bavaria, Wuerzburg, Bavaria, Germany, ⁵Medizinische Klinik und Poliklinik I, Universitaetsklinikum Wuerzburg, Wuerzburg, Bavaria, Germany

A retrospectively triggered approach to high temporal resolution dynamic T1 quantification in small rodent myocardium is demonstrated. An inversion recovery snapshot FLASH method is used. The retrospective approach allows to correct for drift in the triggering and to chose the highest temporal resolution afforded by SNR. A Manganese Enhanced MRI (MEMRI) experiment in rats is shown. The drift in triggering is corrected automatically and a temporal resolution of 66s is achieved.

Helene Feliciano^1,2, Matthias Stuber^1,2, and Ruud B. van Heeswijk^1,2
1Radiology, University Hospital (CHUV), and University of Lausanne (UNIL), Lausanne, Switzerland, ²Center for Biomedical Imaging (CIBM), Lausanne, Switzerland

A radial T₂ mapping sequence that makes use of a cyclically alternating T₂Prep was developed at 3T to avoid the adverse effects of respiratory or RR variability on T₂quantification. Bloch simulations and phantom experiments were performed to compare the thus obtained T₂ maps with that of a standard sequential T₂ mapping approach. In 9 healthy volunteers it was confirmed that more robust T₂ mapping is obtained with alternating T₂ preparation.

Avinash Kali^1,2, Ivan Cokic¹, Hsin-Jung Yang^1,2, Richard Tang¹, and Rohan Dharmakumar^1,3
1Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States, ²Bioengineering, University of California, Los Angeles, CA, United States, ³Department of Medicine, University of California, Los Angeles, CA, United States

We investigated whether stagnant blood within permanently occluded vasculature in non-reperfused myocardial infarction (MI) could lead to chronic iron deposition within MI territories. T2* maps and Late Gadolinium Enhancement images were acquired from canines subjected to permanent ligation of LAD at 7 days and 4 months post-MI. Relative to remote myocardium, 42.6% T2* loss was observed within the MI territories at 7 days post-MI, and 39.1% T2* loss was observed within the MI territories at 4 months post-MI. Mean iron volume was 2.1% of the total LV at 7 days post-MI and 1.9% of the total LV at 4 months post-MI. Chronic iron deposition can occur in non-reperfused MIs.

Yanjie Zhu¹, Yinzhu Gao¹, Qi Yang², Min Pan¹, Xin Liu¹, and Yiu-Cho Chung^1
1Paul C. Lauterbur Research Centre for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China,²Radiology Department, Xuanwu Hospital Capital Medical University, Beijing, China

Myocardial T1 mapping is useful in the diagnosis of myocardial fibrosis. The MOLLI method is sensitive to arrhythmia, tissue T2 values etc. and underestimates T1. We propose an arrhythmia insensitive myocardial T1 mapping technique, IR-rttfl. It performs realtime turboflash acquisition after an inversion pulse to sample the recovery of inverted magnetization for about 6 seconds. Diastolic images are selected retrospectively to estimate T1 map. In phantoms, IR-rttfl was more accurate than MOLLI. Results from IR-rttfl were comparable to MOLLI in healthy volunteers and a few infarct patients. The new technique is useful for robust myocardial T1 mapping at 3T.

Sebastian Weingärtner¹, Sebastien Roujol², Mehmet Akcakaya², Tamer Basha³, Warren J Manning^2,4, and Reza Nezafat^2
1Cardiac MR Center, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States, ²Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States, ³Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, United States, ⁴Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States

We propose to perform 2D T1 mapping in a free-breathing NAV gated sequence with the use of a SAPPHIRE magnetization preparation.

William D Rooney¹, Craig S Broberg², and Charles S Springer, Jr.^1
1Advanced Imaging Research Center, Oregon Health & Science University, Portland, Oregon, United States, ²Division of Cardiovascular Medicine, Oregon Health & Science University, Portland, Oregon, United States

The mean intracellular water lifetime, tau_I, is inversely proportional to myocyte metabolic activity. This biomarker is not available when tracer expressions are used to analyze CA-enhanced myocardial T₁ data. We show this with in vivo data from healthy control subjects.

Rui Xia¹, Xi Lu¹, Bing Zhang¹, Yuqing Wang¹, Jie Zheng², and Fabao Gao^1
1Department of radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China, ²Mallinckrodt Institute of Radiology, Washington University School of Medicine in St. Louis, Missouri, United States

In this study, six rats with 30min myocardial ischemia followed by different reperfusion time (3h, 6h, 12h, 24h) were investigated. And the simplified T2-mapping method was implemented at a 7.0T MRI system. We found that the edema size decreased from 3h to 6h, and kept the same between 6h and 24h. Myocardial salvage index increased while infarction size decreased from 6h to 24h. So the longer reperfused time will increase myocardial salvage index between 6h and 24h in the acute myocardial ischemia. In conclusion, reperfusion may be a useful treatment for the early phase of acute myocardial ischemia.

Markus Henningsson¹, Frank Eschbach^1,2, Giel Mens³, Reza Nezafat⁴, Sebastien Roujol⁴, and Rene Botnar^1
1Imaging Sciences & Biomedical Engineering, King's College London, London, United Kingdom, ²Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands, ³Philips Healthcare, Best, Netherlands, ⁴Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States

A method to take into account contrast material wash-out for 3D late gadolinium enhancement is proposed and validated in phantoms and in-vivo.

Rajesh Dash¹, Yuka Matsuura¹, Paul J Kim¹, Hadas Shiran¹, Phillip Harnish², Michael V McConnell^1,3, and Phillip C. Yang^1
1Stanford University, Stanford, CA, United States, ²Eagle Vision Pharmaceutical Corporation, PA, United States, ³Engineering, Stanford University, Stanford, CA, United States

Delayed Enhanced MRI (DEMRI) with gadolinium (Gd) has non-specific distribution properties and may overestimate myocardial infarct size. Conversely, Manganese (Mn2+) uptake into live, active cells via L-type Ca2+ channels is specific for live cardiomyocytes. From earlier work with animal MI models in our lab, Manganese-Enhanced MRI (MEMRI) has demonstrated its utility in identifying viable myocardium. We performed dual-contrast DEMRI-MEMRI in humans with ischemic cardiomyopathy. MEMRI infarct volumes were significantly lower than DEMRI, similar to findings in small and large animal models. MEMRI complements DEMRI to accurately delineate the peri-infarct region and viable myocardium in patients with ischemic heart disease.

Hung-Hsuan Wang¹, Hsin-Hui Chiu², Wen-Yih Isaac Tseng³, and Hsu-Hsia Peng^1
1Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan, ²Pediatrics, Taipei Medical University Hospital, Taipei, Taiwan,³Center for Optoelectronic Biomedicine, College of Medicine, National Taiwan University, Taipei, Taiwan

The purpose of this study is to observe the aortic root vortex and to quantify vorticity in specific sites along the aorta with usage of phase-contrast MRI so as to realize the impact of vortical flow on the risk of aortic dissection. In the velocity vector fields in left ventricular outflow track view, the presence of vortical flow at peak systole and the absence of vortices at end systole may attribute to the dilated aortic root in MFS patients. The quantified vorticity also showed decreased values for MFS patients, particular in the sinotubular junction.

Rizwan Ahmad¹, Ning Jin², Yu Ding³, and Orlando P Simonetti^3
1Electrical Engineering, The Ohio State University, Columbus, OH, United States, ²Siemens Healthcare, Columbus, OH, United States, ³Internal Medicine, The Ohio State University, Columbus, OH, United States

The purpose of this work is to develop a new approach to deriving blood velocity estimates from phase-contrast MRI data. Different directional components of velocity may have different temporal frequency contents. Traditional linear methods treat all velocity components equally, i.e., they assign equal bandwidth to each component even when the true frequency contents of the components are widely different. To overcome this limitation, we propose an adaptive formulation, where the bandwidth of each velocity component is adapted based on a current estimate of its temporal frequency contents, leading to improved temporal resolution and reduced artifacts.

Wouter V Potters¹, Merih Cibis², Frank JH Gijsen², Henk A Marquering¹, Ed vanBavel³, Jolanda Wentzel², and Aart J Nederveen^1
1Radiology, Academic Medical Center, Amsterdam, Netherlands, ²Biomedical Engineering, Erasmus Medical Center, Rotterdam, Netherlands, ³Biomedical Engineering & Physics, Academic Medical Center, Amsterdam, Netherlands

Remodeling of the vessel wall is associated with wall shear stress (WSS) magnitude. It has been suggested that local low or high WSS may respectively promote or prevent atherosclerotic lesions in the carotid vessel wall. The current gold standard for WSS quantification is computational fluid dynamic (CFD), which requires extensive computational power and non-clinical expertise. Time-resolved phase contrast MRI data provides the same velocity information over the cardiac cycle. The purpose of this study was to compare both the WSS magnitude and WSS direction of MRI-based WSS with CFD-based WSS in the carotid bifurcation of healthy volunteers.

Christian Binter¹, Utku Gülan², Verena Knobloch¹, Markus Holzner², and Sebastian Kozerke^1,3
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, ²Institute of Environmental Engineering, ETH Zurich, Zurich, Switzerland, ³Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom

The estimation of energy stored in turbulent flow could provide detailed information about the losses due to obstructed blood flow. Phase-Contrast MRI and Particle Tracking Velocimetry in a replica of the human aortic arch have been employed to quantify this Turbulent Kinetic Energy and assess the influence of voxel size, non-Gaussian velocity distributions and turbulent time scales. Results showed that up to a voxel size of 2 mm the error due to the assumptions of the signal model should be below 5%. However, direct comparison of MRI and Particle Tracking data show systematic errors not explainable by the signal model.

Maria Carr¹, Yuqing Liu², Jason Ng³, James C Carr¹, Daniel Lee³, Jeffrey Goldberger³, and Michael Markl^1,2
1Radiology, Northwestern University, Chicago, Illinois, United States, ²Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States,³Division of Cardiology, Northwestern University, Chicago, Illinois, United States

Atrial fibrillation (AF) is a common cardiac arrhythmia associated with increased morbidity and mortality.1 Patients with AF are at increased risk of systemic embolism (SE) and stroke, which can cause death, disability, and impaired quality of life.1 It is known that AF is associated with an increased risk of thrombus formation within the left atrial (LA) cavity which is a major contributing factor to embolic stroke in this population. Previous MRI and Doppler echocardiography studies have provided evidence that the increased risk of thrombus formation in the left atrium of AF patients may be related to flow abnormalities and specifically decreased blood flow velocity and thus increased stasis which is thought to promote blood clotting. In this context, previous echocardiography studies found that peak left atrial appendage velocities < 0.2m/s constitute a risk factor for thrombus formation and for stroke2. Moreover, a recent 4D flow MRI study has shown that left atrial 3D hemodynamics was significantly different in patients with AF compared to healthy controls3. In addition, prior reports have demonstrated that rates of pulmonary embolism and right atrial (RA) thrombus formation in AF are an order of magnitude less common than systemic embolism (i.e. LA thrombus formation).

Julio Garcia¹, Michael Markl^1,2, Pim van Ooij¹, Susanne Schnell¹, Jeremy Collins¹, S. Chris Malaisrie³, James Carr¹, and Alex J. Barker^1
1Radiology, Northwestern University, Chicago, Illinois, United States, ²Biomedical Engineering, Northwestern University, Illinois, United States, ³Division of Cardiac Surgery, Northwestern University, Chicago, Illinois, United States

Patients with aortic dilation often exhibit eccentric transvalvular flow jets. The angle of the flow jet from the aorta centerline (FJA)has been reported as a risk factor for aortic dilation in bicuspid aortic valve patients. The objective of this study was to develop and apply a new algorithm for the semiautomatic evaluation of FJA using a 3D jet shear layer structure based on 4D flow MRI data.

Jochen von Spiczak¹, Gérard Crelier², Daniel Giese¹, Sebastian Kozerke², David Maintz¹, and Alexander Christian Bunck^1
1Department of Radiology and Neuroradiology, University Hospital of Cologne, Cologne, Germany, ²Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland

It has been shown that vortex blood flow patterns are physiologically present in the heart, aorta, and pulmonary circulation, but can also be correlated to certain pathologies. The purpose of this work was to define new objective and quantitative measures for three-dimensional vortex flow evaluation. These measures were then used for the exemplary characterization of helical blood flow found in the healthy aortic arch (evaluated in 9 healthy subjects), as well as altered flow patterns in pathologically dilated aortas (3 patients).

Zixin Deng^1,2, Guoxi Xie³, Yi He⁴, Nan Zhang⁴, Yutaka Natsuaki⁵, Ning Jin⁵, Xiaoming Bi⁵, Jing An⁶, Xin Liu³, Zhaoqi Zhang⁴, Zhanming Fan⁴, Debiao Li^1,2, and Zhaoyang Fan^1
1Biomedical Imaging Research Institute (BIRI), Cedars-Sinai Medical Center, Los Angeles, CA, United States, ²Department of Bioengineering, UCLA, Los Angeles, California, United States, ³Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, ⁴Department of Radiology, Anzhen Hospital, Beijing, China,⁵MR R&D, Siemens Healthcare, Los Angeles, California, United States, ⁶MR Collaborations NE Asia, Siemens Healthcare, Beijing, China

Fractional flow reserve (FFR) is a diagnostic tool to determine the functional significance of a stenosis. However, it’s an invasive procedure involving catheterization and exposure to radiation. We proposed a non-invasive technique to derive FFR using view sharing (VS) 4D Phase-contrast (PC)-MRI. Image acquisition for VS4D PC-MRI is limited to the quiescent phase and end-expiration to avoid motion-induced errors to the coronaries. In this study, we have shown that the technique can provide accurate velocity measurements and potentially reduce motion-induced errors. ΔP of healthy volunteers were reported and further studies are underway in stenosed coronary arteries of animals and patients.

Petter Dyverfeldt¹, Tino Ebbers¹, and Toste Länne^1,2
1CMIV and Linköping University, Linköping, Sweden, ²County Council of Östergötland, Linköping, Sweden

The purpose of the present study was to evaluate different methods for extracting pulse wave velocity (PWV) from 4D MR velocity data. 6 different methods were implemented and were applied to estimate aortic PWV in 8 young and 8 older normal volunteers. All methods were capable of resolving age-related differences in aortic PWV. However, systematic and significant differences were observed between the methods. These findings indicate that care must be taken when interpreting PWV estimates obtained by different types of methods.

Wouter V Potters¹, Anders Nilsson², Sandra van den Berg¹, Ed vanBavel³, Karin Markenroth Bloch⁴, Freddy Ståhlberg^2,5, and Aart J Nederveen^1
1Radiology, Academic Medical Center, Amsterdam, Netherlands, ²Medical Radiation Physics, Lund University, Lund, Sweden, ³Biomedical Engineering & Physics, Academic Medical Center, Amsterdam, Netherlands, ⁴Philips Healthcare, Lund, Sweden, ⁵Diagnostic Radiology, Lund University, Lund, Sweden

Wall shear stress (WSS) is the force exerted by the flowing blood on the endothelial cells. WSS has been correlated with endothelial function and wall thickness. Quantification of WSS from 4D phase contrast MRI (4DPC) can be performed in the aorta, but is challenging in the diastolic part of the heart cycle due to a low velocity to noise ratio (VNR). A variable VENC 4D PC-MRI (4DvPC) sequence can significantly improve the VNR in diastole. We compared WSS quantification between 4DPC and 4DvPC to see if the improved VNR will also improve the diastolic WSS quantification. Additionally we investigated the WSS reproducibility.

Pim van Ooij¹, Maria Carr¹, Bradley D. Allen¹, David G. Guzzardi², Jeremy Collins¹, James Carr¹, S. Chris Malaisrie³, Paul W. M. Fedak², Patrick McCarthy⁴, Michael Markl^1,5, and Alex J. Barker^1
1Radiology, Northwestern University, Chicago, IL, United States, ²Cardiac Surgery, University of Calgary, Calgary, Alberta, Canada, ³Medicine-Cardiology, Northwestern University, Chicago, IL, United States, ⁴Surgery-Cardiac Surgery, Northwestern University, Chicago, IL, United States, ⁵Biomedical Engineering, Northwestern University, Chicago, IL, United States

In this study, a methodology is presented that enables identification of abnormal WSS, estimated by 4D flow MRI, in patients with bicuspid aortic valve (BAV) by comparison with a cohort-averaged 3D WSS map of healthy controls. 11 BAV patients were compared with a mean±1.96*standard deviation WSS map created from data of 10 controls. In the BAV patients, elevated WSS was predominantly found in the inner (8%) and outer ascending aorta surface (21%) and outer arch surface (16%). Moderate correlations were found between the significant surface area and aortic diameter (R2 of 0.8, 0.5 and 0.4, respectively).

Brett Cowan¹, Yingmin Liu¹, Alistair Young¹, Andreas Greiser², and Peter Speier^2
1University of Auckland, Auckland, Auckland, New Zealand, ²Siemens AG Healthcare Sector, Erlangen, Germany

We present an optimized radial k-space short TE phase contract flow measurement sequence incorporating inversion of alternate slice-selection and flow-encoding gradients, with an optimized three pulse gradient profile to de-couple VENC from slice thickness. Also, correction of gradient timing error during slice selection led to improved robustness with in-plane slice shifts.

Pim van Ooij¹, Edouard Semaan¹, Zoran Stankovic¹, Susanne Schnell¹, Shivraman Giri², Alex J Barker¹, and Michael Markl^1,3
1Radiology, Northwestern University, Chicago, IL, United States, ²Siemens Healthcare, Chicago, IL, United States, ³Biomedical Engineering, Northwestern University, Chicago, IL, United States

To avoid breathing artifacts in 4D flow MRI, respiratory motion is controlled by a navigator placed on the diaphragm. Scan efficiency and scan time can be highly variable between subjects. A novel navigator strategy is proposed allowing for fixed scan efficiency and scan time by adjusting the lower threshold of the acceptance window according to a user-defined acceptance percentage. 4D flow MRI was performed with user-defined acceptance percentages of 60%, 80% and 100% and compared with conventional navigator settings. No differences were found in image quality or flow quantification while avoiding scan time uncertainties in 4D flow MRI.

Christian Binter¹, Alexander Gotschy^1,2, Robert Manka^1,2, Simon H. Sündermann³, and Sebastian Kozerke^1,4
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, ²Dept. of Cardiology, University Hospital Zurich, Zurich, Switzerland, ³Division of Cardiovascular Surgery, University Hospital Zurich, Zurich, Switzerland, ⁴Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom

The classification of aortic stenosis severity using Doppler sonography is based on the velocities across the valve and does not necessarily reflect the additional workload of the heart. Phase-Contrast MRI offers the possibility of quantifying the energy dissipated in turbulent flow and thereby potentially providing an objective measure of disease severity. Results from 16 patients and 10 age-matched controls are presented and compared to conventional diagnostic parameters determined by Doppler sonography. To analyze robustness, inter- and intra-observer variability analysis is performed.

Erin K Englund¹, Zachary B Rodgers¹, Prithvi Shiva Kumar², Michael C Langham³, Julio A Chirinos², Raymond R Townsend², and Felix W Wehrli^3
1Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States, ²Department of Medicine, University of Pennsylvania, Philadelphia, PA, United States, ³Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States

Pulse wave velocity (PWV) is the speed at which the systolic wave front travels in an artery, and provides a measure of arterial stiffness. While arterial tonometry is a simple method to quantify central artery PWV, it cannot assess PWV in specific segments. MRI measurement of non-gated velocity-encoded projections can provide vessel-specific quantification of PWV in the carotid arteries, aortic arch, descending aorta, and iliofemoral arteries. A full-body segmental MRI PWV protocol was evaluated nine young and nine old healthy subjects compared to arterial tonometry. MRI and tonometry-derived results show that PWV increases with age in each arterial segment.

MJ Negahdar^1,2, Mo Kadbi¹, Michael Kendrick³, Rita Longaker⁴, Marcus Stoddard⁴, and Amir Amini^1,2
1Electrical and Computer Engineering, University of Louisville, Louisville, KY, United States, ²Division of Research, VA Medical Center, Louisville, KY, United States,³Department of Radiology, VA medical center, KY, United States, ⁴Cardiovascular Division, University of Louisville, KY, United States

4D flow MRI can derive 3D velocity of flow in a 3D volume in a shorter time in comparison to conventional methods. 4D flow can be used as an alternative and complimentary tool for assessment of valvular disease. In this abstract, we perform 3-way comparison of hemodynamic parameters derived from a new 4D UTE flow sequence with conventional 4D flow and Doppler Echocardiography in 6 patients with mild to moderate Aortic Stenosis. Results demonstrate good degree of correlation between the 3 methods.

Eduardo G. Gonzalez¹ and Joao L. A. Carvalho^1
1Department of Electrical Engineering, University of Brasilia, Brasilia, DF, Brazil

The underlying assumption with phase contrast (PC) is that all spins within a voxel move at the same velocity. This assumption is broken if the voxel is partially occupied by static spins or located at the viscous sublayer, or if the flow is complex or turbulent. We show that PC measurements may be accurately modeled as the mean velocity of all spins within each voxel. The proposed model, based on the spatial-velocity distribution of spins, could be useful towards bettering our understanding of partial volume effects in PC MRI velocimetry, especially if T₁ contrast, in-flow enhancement, and noise are incorporated.

Elizabeth Iffrig¹, Pardeep Mittal², Gail Peters², John Oshinski^1,2, and William Robert Taylor^1,3
1Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States, ²Radiology, Emory University, Georgia, United States, ³Cardiology, Emory University, Georgia, United States

The purpose of this project is to evaluate the influence of uterine artery blood flow on aortic oscillatory hemodynamics and whether this can explain differences observed in this region between men and women. To accomplish this we recruited 10 patients who were undergoing evaluation for interventional therapy to treat uterine fibroids. We calculated flow through the abdominal aorta and iliac arteries and compared the results to 7 healthy women and 11 healthy men. We found significant differences between all groups suggesting that uterine artery blood flow plays a significant role in the differences in aortic hemodynamics between men and women.

Patrick Magrath¹, Michael Markl^1,2, Aurelien F. Stalder³, Mehmet A. Gulsun⁴, and Bruce Spottiswoode^5
1Biomedical Engineering, Northwestern University, Chicago, Illinois, United States, ²Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States, ³Siemens AG Healthcare sector, Erlangen, Germany, ⁴Imaging and Computer Vision, Siemens Corporation, Princeton, New Jersey, United States, ⁵Cardiovascular MR R&D, Siemens Healthcare, Chicago, Illinois, United States

Pulse wave velocity (PWV) provides a measure of vessel stiffness and atherosclerosis. This work presents a novel, second order surface fitting approach for estimating pulse wave velocity using a large number of flow evaluation planes extracted from 4D flow data. This approach was combined with centerline determination and lumen segmentation algorithms for a rapid and semi-automated assessment of PWV, with results that are more stable to parameter variations than those calculated using time-to-foot and surface fitting methods. Further investigation into the use of this and other complex fitting algorithms is warranted.

Kristine Skårdal^1,2, Emil K. S. Espe^1,2, Magnus Aronsen^1,2, Lili Zhang^1,2, and Ivar Sjaastad^1,2
1Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Oslo, Norway, ²KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Oslo, Norway

Assessment of diastolic dysfunction is important in basic research, involved in studying the mechanisms behind heart failure with preserved ejection fraction. However, more optimal methods are needed to study diastolic function in vivo in small animals. For the first time, phase contrast MRI (PC-MRI) has been extended to evaluate mitral inflow in a rat model. We found that PC-MRI can detect alterations in mitral flow, showing increased peak flow and deceleration rate of the mitral flow in response to disease. The results further advance the potential of PC-MRI as a complete method for evaluation of diastolic dysfunction in rodents.

Pan-Ki Kim¹, Jeongmin Kwon¹, Hyeonjin Kim^1,2, Eun-Ah Park^1,2, and Whal Lee^1,2
1Seoul National University, Seoul, Korea, ²Seoul National Univ. Hospital, Seoul, Korea

Phase contrast magnetic resonance image (PCMRI) is regularly used to assess the interest velocity. To analysis using velocity curve, the time resolved PCMRI requires higher temporal resolution. In this study, the proposed PCMRI method is designed to concurrently improve the temporal-resolution and VNR.

Alejandro Matias Pino Verdugo^1,2, Joaquin Mura³, and Sergio Uribe^2,4
1Physics Department, Pontificia Universidad Católica de Chile, Santiago, Santiago, Chile, ²Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Santiago, Chile, ³Civil Engineering School, Pontificia Universidad Católica de Valparaiso, Valparaiso, Chile, ⁴Radiology Department School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile

4D flow imaging has shown great potential to study different cardiovascular diseases. However, the velocity data provided by 4D flow is highly prone to be affected by respiratory motion due to the long acquisition time, inhomogeneities due to large FOV, and partial volume effects due to low spatial resolutions, among others. Some of these terms can be corrected by applying a linear phase correction estimated from static tissues; however, a great amount of inaccuracies may still remain. Another way to correct the data is to assume that blood flow is incompressible and to enforce the velocity field to be divergence free. Lately, some methods have been proposed to enforce divergence free to the velocity field. In this work, we propose a novel method to enforce divergence free to the velocity data by calculating a velocity corrector for each pixel in the domain of interest.

Hung-Hsuan Wang¹, Hsin-Hui Chiu², Shih-Han Hung³, Wen-Yih Isaac Tseng⁴, and Hsu-Hsia Peng^1
1Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan, ²Pediatrics, Taipei Medical University Hospital, Taipei, Taiwan,³Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan, ⁴Center for Optoelectronic Biomedicine, College of Medicine, National Taiwan University, Taipei, Taiwan

One of the most life-threatening complications for Marfan syndrome (MFS) patients is aortic dissection or rupture. Medical therapy to reduce the rate of aortic dilatation and risk of dissection, once MFS has been diagnosed, is now advocated. The purpose of this study is to analyze regional wall shear stress (WSS) and oscillatory shear index along the aorta of MFS patients with usage of noninvasive phase-contrast MRI. The values of WSS were significant lower in MFS patients. Regional distribution of WSSaxial displayed the chaotic flows in specific sites of the aorta, which may indicate potential sites with high risk of dissection.

Da Wang^1,2, Jiaxin Shao¹, Stanislas Rapacchi¹, Matthew J. Middione^1,2, Yutaka Natsuaki³, Gerhard Laub³, Daniel B. Ennis^1,2, and Peng Hu^1,2
1Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, United States, ²Biomedical Physics Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, California, United States, ³SIEMENS, California, United States

PC-MRI is commonly acquired using interleaved flow-compensated (FC) and flow-encoded (FE) echoes. We hypothesize that the FC data, which represents background phase, does not change significantly over time in certain applications, such as common carotids artery. Therefore, we proposed to under-sample the FC data and use a view-sharing approach (FCVS) to synthesize a composite FC frame for each corresponding FE frame. FCVS was evaluated in prospective in vivo study with six healthy volunteers and compared with a standard FCFE PC-MRI on peak velocity and flow measurements.

Nicholas Scott Burris¹, Monica Sigovan², David Saloner¹, and Michael Douglas Hope^1
1Radiology, University of California San Francisco, San Francisco, CA, United States, ²University of Lyon, CREATIS Laboratory, Lyon, France

Bicuspid aortic valve fusion patterns (most commonly RL or RN) are associated with unique flow patterns aorta and unique patters of aortic dilation. Peak systolic flow displacement, is a parameter derived from cardiac MRI phase-contrast data, and quantifies the degree of flow eccentricity from the vessel midline. We investigated the direction of flow displacement as it relates to valve fusion pattern with a goal of better understanding the unique flow patterns created by differing valve fusion patterns. We found that RL fusion was highly associated with rightward flow jets, while RN fusion was associated with leftward or midline flow jets.

Sven Petersson¹, Petter Dyverfeldt¹, Andreas Sigfridsson², Carl Johan Carlhäll^1,3, and Tino Ebbers^1
1CMIV and Linköping University, Linköping, Sweden, ²Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden, ³Department of Clinical Physiology, County Council of Östergötland, Linköping, Sweden

Spiral 4D flow MRI has recently been validated for the assessment of aortic and intra-cardiac velocities. This study compares the performance of spiral and Cartesian flow MRI for the assessment of velocity and turbulent kinetic energy in stenotic flow. Spiral trajectories are relatively insensitive to flow artifacts and therefore well suited for stenotic flow assessment. The performance was evaluated by in-vitro measurements on a stenotic flow phantom. The spiral sequence was three times faster and less sensitive to displacement artifacts compared to the Cartesian sequence. In conclusion, spiral flow MRI appears favorable for the assessment of stenotic flow.

Vinicius C. Rispoli^1,2, Jon-Fredrik Nielsen³, Krishna S. Nayak⁴, and Joao L. A. Carvalho^1
1Department of Electrical Engineering, University of Brasilia, Brasilia, DF, Brazil, ²UnB Gama Faculty, University of Brasilia, Brasilia, DF, Brazil, ³Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States, ⁴Electrical Engineering, University of Southern California, Los Angeles, CA, United States

Velocity fields measured with phase contrast (PC) MRI generally do not satisfy the equations of fluid dynamics. A framework for using MRI measurements to construct a flow field that satisfies such equation was previously described. However, only one MRI-measured velocity component was used to drive the computational fluid dynamics (CFD) solution. We investigate the use of 3D PC-MRI to guide the CFD calculations. The results show that MRI-guided CFD is effective in correcting the MRI-measured velocity field, and suggest that using 3D PC-MRI to guide the CFD solution produces results that are more truthful to the MRI measurements.

Petter Dyverfeldt¹, Tino Ebbers¹, and Toste Länne^1
1CMIV and Linköping University, Linköping, Sweden

Vascular stiffness is known to vary regionally along the aorta. This may be of particular interest with respect to focal diseases such as aneurysms. We implemented a semi-automated method to estimate regional PWV. The method was applied to estimate PWV in three equally sized segments in the descending aorta in 8 young and 8 older normal volunteer. The age-related differences in regional PWV observed agreed with previous studies and suggest that the PWV in the proximal and mid segments of the descending aorta increase more rapidly with age than the PWV in the distal descending aorta.

Julio Sotelo^1,2, Jesús Urbina^3,4, Ernesto Ortiz⁵, Cristian Tejos^3,6, Israel Valverde^7,8, Daniel E. Hurtado^5,9, and Sergio Uribe^3,4
1Biomedical Imaging Center, Pontificia Universidad Catolica de Chile, Santiago, Santiago, Chile, ²Electrical Engineering, Pontificia Universidad Catolica de Chile, Santiago, Santiago, Chile, ³Biomedical Imaging Center, Pontificia Universidad Catolica de Chile, Santiago, Chile, ⁴Radiology, School of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile, ⁵Structural Engineering, Pontificia Universidad Catolica de Chile, Santiago, Chile, ⁶Electrical Engineering, Pontificia Universidad Catolica de Chile, Santiago, Chile, ⁷Pediatric Cardiology Unit, Hospital Virgen del Rocio, Sevilla, Spain, ⁸Division of Cardiovascular Physiology, Institute of Biomedicine Seville (IBIS), Hospital Universitario Virgen de Rocio/CSIC/University of Seville, Sevilla, Spain, ⁹Biomedical Engineering Group, Pontificia Universidad Catolica de Chile, Santiago, Chile

We present a novel method for calculating the WSS distribution in the aorta based on finite-element interpolations. The velocity field obtained from PC-MRI data was interpolated using linear triangular finite-elements and the axial WSS vector was obtained from a global least-squares stress-projection method. We used a Poiseuille flow profile and data acquired in volunteers for evaluating the robustness of the method. Our results showed that the local WSS values were in good agreement with the theoretical Poiseuille values and observed significant difference in the volunteers study in comparison to previews reported methods.

Patrick Magrath¹, Alex J. Barker², Timothy J. Carroll^1,2, and Michael Markl^1,2
1Biomedical Engineering, Northwestern University, Chicago, Illinois, United States, ²Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States

2D MRI Tissue Phase Mapping (TPM) allows the quantitative segmental evaluation of 3-directional myocardial velocities with high temporal resolution and full LV coverage. However, TPM analysis requires LV segmentation which is challenging due to the low inherent contrast in anatomic TPM images and can thus be time consuming. This study explores a novel semi-automated myocardial segmentation that utilizes both anatomic and functional information combined with cluster analysis to analyze TPM data with minimal user interaction. The feasibility of the new technique was demonstrated in a pilot study which showed good performance compared to manual segmentation as the reference standard.

Pei-Hsin Wu¹, Hsiao-Wen Chung¹, Cheng-Wen Ko², and Ming-Ting Wu^3
1Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan, ²Department of Computer Science and Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan, ³Department of Radiology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan

Pulmonary regurgitation is commonly observed in patients after repaired tetralogy of Fallot. The regurgitation fraction measured via PC-MRI to evaluate the need for pulmonary valve replacement, however, does not contain spatial flow inhomogeneity information. Since forward and regurgitant flow could occur in the pulmonary arteries and be recorded simultaneously in any single cardiac phase, we propose a newly defined parameter which explores both the spatial and temporal existence of blood flow regurgitation by pixelwise analysis of flow velocity. Preliminary result on main pulmonary arteries from ten patients suggests potential assistance value in the understanding of pathophysiology in tetralogy of Fallot.

Teng-Chieh Cheng¹, Yi-Jui Liu¹, Yi-Hsiung Lee², Wen-Chau Wu³, Teng-Yi Huang⁴, Chao-Chun Lin⁵, Chia-Wei Lin⁵, and Wu-Chung Shen^5
1Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan, ²Ph.D. Program of Electrical and Communications Engineering, Feng China University, Taichung, Taiwan, ³Graduate Institute of Oncology, National Taiwan University, Taipei, Taiwan, ⁴Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan, ⁵Department of Radiology, China Medical University Hospital, Taichung, Taiwan

The long scan time in cine PCMRI is due to high temporal and high spatial resolution. It can accelerate scan time using keyhole technique, but also make blurred image in phase encoding direction. Although the blurred image can be modified and looks like a high resolution image, the retrieved intensity value in phase image may be different with original value. In this study, simulations on the numerical phantom and reducing the number of central k-space line from a real cine PCMRI with high temporal and spatial resolution were used to evaluate the phase cross-contamination by keyhole scan.

Pei-Hsin Wu¹, Hsiao-Wen Chung¹, Ming-Ting Wu², and Cheng-Wen Ko^3
1Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan, ²Department of Radiology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, ³Department of Computer Science and Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan

Previous studies demonstrate that branch pulmonary arteries show flow pattern asymmetry in patients after repair of Tetralogy of Fallot. On the other hand, the Reynolds number (Re) has been viewed as an indicator of flow instability and directly relates with volumetric flow and diameter. In this study, we investigate the flow behavior by using Reynolds number to examine whether there is difference between branch pulmonary arteries. The preliminary analyses show Re-related indices of RPA are significantly higher than that of LPA, which may imply the RPA is prone to flow instability compared to LPA.

Volker Herold¹, Alexander Gotschy¹, Patrick Winter¹, Eberhard Rommel¹, Wolfgang Rudolf Bauer², and Peter Michael Jakob^1
1University of Wuerzburg, Wuerzburg, Bavaria, Germany, ²Medizinische Universitätsklinik, University of Wuerzburg, Bavaria, Germany

Atherosclerotic plaque burden and local elastic parameters such as the local pulse wave velocity (PWV) are distributed inhomogeneously along the diseased blood vessels. Therefore it is important to not only detect elastic parameters at one location but to examine the distribution of elastic properties along the entire vessel. The QA-method allows the quantification of the local PWV at one particular location based on PC-CINE-MRI measurements. Using a k-t BLAST technique, we could significantly accelerate the data acquisition and thus realizing the quantification of the local PWV at 10 different sites along the murine aorta in one experiment.

Volker Rasche¹, Robert Kohlschmitt², David Schahbasian², Karl-Heinz Orend², and Alexander Oberhuber^2
1Internal Medicine II, Ulm University, Ulm, BW, Germany, ²Thoracic and Vascular Surgery, Ulm University, BW, Germany

Thoracic Endovascular Aortic Repair (TEVAR) is often associated with graft related complications such as endoleaks, kinking, infolding, and stentgraft migration, disconformability and especially disattachment phenomena. It is the objective of this study to investigate the potential of MRI for assessing the impact of the stents on blood flow and vessel compliance.

Maya Khalifé¹, Ludovic de Rochefort¹, Dima Rodriguez¹, and Emmanuel Durand^1
1Imagerie par Résonance Magnétique Médicale et Multi-modalités (IR4M), Université Paris-Sud- CNRS, Orsay, France

Motion encoding sequences require a long acquisition time. To reduce motion artifacts on the time-resolved images, a relatively long breath-hold, reaching 25 to 30 seconds, is required from the patient. A technique that allows dynamic acquisition time optimization through field of view (FOV) reduction was proposed and studied in order to reduce breath-hold duration. The technique unfolds fold-over regions by complex difference of two images, one of which is motion encoded and the other acquired without an encoding gradient. By implementing this method, Proof-of-concept is demonstrated on a volunteer providing stimulating preliminary results in order to achieve multi-dimensional velocity and acceleration mapping in a single breath-hold.

Yi Wang¹, Yang Cheng¹, and Marguerite Roth^1
1St. Francis Hospital, Roslyn, NY, United States

Aortic vessel becomes stiffer with normal aging, as well as vessel wall pathology. We evaluated aortic pulse wave velocity (as a surrogate of aortic compliance) and its relationship to age and cardiac function measurements in 291 normals with various age distributions and repeated the evaluation at 5-year and 10-year followup.

Jonathan M. Chia¹ and Zhiyue J. Wang^2,3
1Philips Healthcare, Cleveland, OH, United States, ²Children's Medical Center, Dallas, Texas, United States, ³University of Texas Southwestern, Dallas, Texas, United States

This work looks at the feasibility of performing sparse sampling in high resolution phase contrast imaging using a CS-SENSE reconstruction algorithm. Images were simulated at 25, 18, and 14% sparse acquisition and compared against a clinical acquired dataset through region of interest analysis. Undersampled data showed slight underestimation of quantitative values while still maintaining an accurate flow curve behavior. The intrinsic nature of undersampling most likely leads to quantitative discrepancy. CS-SENSE is shown to be feasible and promising achieving accurate quantitative data.

Willem Bouvy¹, Geert Jan Biessels², Jaap Kappelle², Peter R Luijten³, and Jaco Zwanenburg^3
1Brain Center Rudolf Magnus, Department of Neurology, Utrecht University Medical Centre, Utrecht, Utrecht, Netherlands, ²Brain Center Rudolf Magnus, Department of Neurology, Utrecht University Medical Centre, Utrecht, Netherlands, ³Department of Radiology, Utrecht University Medical Centre, Utrecht, Netherlands

Aim: To measure blood flow velocity and pulsatility in small perforating arteries in the cerebral white matter with 7 Tesla Qflow MRI. Method: Six volunteers aged 18-30 were scanned, and twelve perforating arteries were analyzed. Results: Flow was pulsatile in all arteries, with a mean velocity of 0.9cm/s (range 0.23-2.01), and mean pulsatility index of 0.51(range 0.29-0.83). Conclusion: Velocity pulsations in small arteries in the white matter can be directly measured in humans with 7 Tesla Qflow MRI. Partial volume effects and the direction of flow measurement may have affected our results, and further validation of this method is needed.

Davide Piccini^1,2, Bénédicte Maréchal^1,3, Simone Coppo², Jérôme Chaptinel², Gabriele Bonanno², Gunnar Krueger^1,3, Juerg Schwitter⁴, and Matthias Stuber^2
1Advanced Clinical Imaging Technology, Siemens Healthcare IM BM PI, Lausanne, Switzerland, ²Department of Radiology, University Hospital (CHUV) and University of Lausanne (UNIL) / Center for Biomedical Imaging (CIBM), Lausanne, Switzerland, ³CIBM-AIT, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, ⁴Division of Cardiology and Cardiac MR Center, University Hospital of Lausanne (CHUV), Lausanne, Switzerland

In the field of self-navigated (SN) coronary MRA, several approaches have been proposed for the extraction of clean respiratory signals. The coils used for SN are usually either manually selected or fixed and dependent on the hardware of the scanner. In this work, a method for automated subject-specific coil selection for SN, which uses atlas-based image segmentation techniques, is described and compared to manual selection performed by expert reviewers and fixed coil selection. While the automated coil selection performs equally well as the manual selection, a significant improvement in image quality is obtained in comparison to a fixed coil selection.

Thomas Hope¹, Rizwan Aslam¹, Judy Yee¹, Anait Sesi¹, Joseph Rapp¹, Christopher Owens¹, and David Saloner^1
1Department of Radiology, UCSF/SFVA, San Francisco, CA, United States

We describe the first use of Ferumoxytol as an MR contrast agent for use in MR runoffs. In order to minimize T2* effects, the agent must be diluted during the dynamic arterial phases. When diluted, ferumoxytol performs well as an alternative contrast agent in patients with renal disease.

Davide Piccini^1,2, Simone Coppo², Tobias Rutz³, Giulia Ginami², Jean-Baptiste Ledoux⁴, Mathieu Gerber⁴, Juerg Schwitter³, and Matthias Stuber^2
1Advanced Clinical Imaging Technology, Siemens Healthcare IM BM PI, Lausanne, Switzerland, ²Department of Radiology, University Hospital (CHUV) and University of Lausanne (UNIL) / Center for Biomedical Imaging (CIBM), Lausanne, Switzerland, ³Division of Cardiology and Cardiac MR Center, University Hospital of Lausanne (CHUV), Lausanne, Switzerland, ⁴Department of Radiology, University Hospital of Lausanne (CHUV), Lausanne, Switzerland

A respiratory self-navigated 3D whole-heart technique was extended to inversion-recovery for 3D late gadolinium enhancement (LGE) imaging and integrated into a dedicated protocol where the same sequence was acquired also pre-contrast and during slow infusion, with T2 preparation, for comparison. Signal and contrast to noise, as well as vessel length and sharpness increased in the slow infusion datasets, while the 3D LGE datasets allow for combined coronary tree and scar tissue visualization in one single acquisition. The 3D LGE dataset can also be reformatted for color-coded 3D visualization and might be useful for planning ablation as part of re-synchronization procedures.

Nii Okai Addy¹, R Reeve Ingle¹, Dwight G Nishimura¹, and Bob S Hu^1,2
1Electrical Engineering, Stanford University, Stanford, CA, United States, ²Cardiology, Palo Alto Medical Foundation, Palo Alto, CA, United States

High spatial resolution is critical for assessing coronary artery disease. The feasibility of a sub-millimeter variable-density 3D Cones acquisition, combining parallel imaging and compressed sensing, is shown for patient studies.

Stephen J Gandy¹, Jill Belch², Ian Cavin¹, Elena Crowe³, Jennifer Macfarlane¹, Patricia Martin³, Shona Matthew², Matthew Lambert², R Stephen Nicholas¹, Allan Struthers², Shelley Waugh¹, Jonathan Weir-McCall², Richard White³, and J Graeme Houston^2
1NHS Tayside Medical Physics, Ninewells Hospital, Dundee, Angus, United Kingdom, ²School of Medicine, University of Dundee, Dundee, Angus, United Kingdom, ³NHS Tayside Clinical Radiology, Ninewells Hospital, Dundee, Angus, United Kingdom

The aim of this study was to test a novel cardiovascular MRI protocol capable of acquiring cardiac MR (CMR) data (including myocardial delayed enhancement) and whole-body MRA (WB-MRA) data within a single examination. The protocol was divided into five phases, consisting of (i) localisers, (ii) CINE MR of left ventricular function, (iii) WB-MRA part 1, (iv) myocardial delayed enhancement, and (v) WB-MRA part II. CMR segmentation and WB-MRA scoring evaluation was undertaken by two teams of multiple observers, and good repeatability was established. The protocol was well tolerated by volunteers and therefore deemed suitable for larger population-based studies.

Michaela Schmidt¹, Stefan Haneder², Ulrike I. Attenberger², Melissa M. Ong², Mariappan Nadar³, Peter Schmitt¹, Xiaoming Bi⁴, Stefan O. Schoenberg², and Michael O. Zenge^1
1Siemens AG Healthcare Sector, Erlangen, Germany, ²University Medical Centre Mannheim, Institute of Clinical Radiology and Nuclear Medicine, Germany, ³Siemens Corporate Technology, Princeton, NJ, United States, ⁴Siemens Healthcare, LA, CA, United States

Inversion-prepared b-SSFP imaging is a suitable approach to perform non-contrast-enhanced (non-CE) MR angiography (MRA) of the renal arteries. The current study aims at a radical acceleration of the data acquisition by combining sparse, incoherent sampling with L1-regularized iterative SENSE reconstruction. Non-CE MRA was performed in 20 healthy volunteers with sub-sampling rates of 6.4, 9.0 and 11.5 and compared to a reference protocol with rate 2 GRAPPA acceleration. In comparison to the reference protocol, the proposed highly accelerated imaging method performed very competitively with acceleration rates up to 9 with radical data acquisition time reductions up to a factor of 5.

Orestis Vardoulis¹, Diego Gallo², Davide Piccini^3,4, Pierre Monney⁵, Umberto Morbiducci², Gabriele Bonanno³, Nikos Stergiopulos¹, and Juerg Schwitter^5
1LHTC-IBI-STI, EPFL, Lausanne, Vaud, Switzerland, ²Mechanics Department, Politecnico di Torino, Piemonte, Italy, ³Center for Biomedical Imaging (CIBM), Department of Radiology, University Hospital (CHUV) and University of Lausanne (UNIL), Vaud, Switzerland, ⁴Siemens Healthcare IM BM PI, Advanced Clinical Imaging Technology, Vaud, Switzerland, ⁵Centre de la RM cardiaque, CHUV, Vaud, Switzerland

We retrospectively analysed 3D MRA datasets of thoracic anatomy for 10 subjects with suspected diastolic dysfunction and a control group with normal LV geometry and function. The aim was to identify the aortic morphological features that differ significantly between healthy and diseased subjects. Initially, the aortic geometries were segmented. Centerlines were extracted, the dihedral angles were estimated and the corresponding vectors of curvature, torsion and cross sectional area were calculated. The non-parametric Mann Whitney U test showed that the dihedral angle and torsion amplitude differed significantly in the region between the aortic valve and the ascending aorta.

Yuki Ohmoto-Sekine¹, Junji Takahashi², Makiko Ishihara³, Takashi Yoshida², Sachiko Isono⁴, Shigehide Kuhara⁴, Yasuji Arase¹, and Mitsue Miyazaki^5
1Health Management Center, Toranomon Hospital, Tokyo, Japan, ²Radiology Dept., Toranomon Hospital, Tokyo, Japan, ³Imaging Center, Toranomon Hospital, Tokyo, Japan, ⁴Toshiba Medical Systems, Tochigi, Japan, ⁵Toshiba Medical Research Institute, Illinois, United States

Whole-Heart Magnetic Resonance Coronary Angiography (WH MRCA) is proven to be a value for non-invasive assessment of coronary arteries. However, to our knowledge, there are no studies demonstrating the reproducibility of WH MRCA. Therefore, we confirm the reproducibility of WH MRCA in clinical setting on health checkups. The result showed there was a high degree of inter-scan agreement for all three coronary arteries, so that the reproducibility was clinically acceptable.

Joonsung Choi¹, Yeji Han¹, and HyunWook Park^1
1Department of Electrical Engineering, KAIST, Daejeon, Korea

A novel TOF technique for high contrast angiography without slab boundary artifacts

Yuriko Suzuki¹, Wouter M Teeuwisse², Sophie Schmid², Michael Helle³, Marc Van Cauteren⁴, and Matthias JP van Osch^2
1Philips Electronics Japan, Minato-ku, Tokyo, Japan, ²C.J.Gorter Center for High Field MRI, Departement of Radiology, Leiden University Medical Center, Leiden, Netherlands, ³Philips Research Laboratories, Hamburg, Germany, ⁴Philips Healthcare Asia Pasific, Tokyo, Japan

Time-resolved 4D-MRA provides important information for cerebrovascular diseases. The use of superselective pCASL for time-resolved 4D-MRA is, however, impeded because of the need for a long labeling duration. Hadamard time-encoded pCASL was recently proposed as an approach to increase the SNR and time efficiency of multiple timing acquisitions. The purpose of this study is to introduce a new superselective pCASL 4D-MRA sequence which combines the Hadamard encoding pCASL and Look-Locker readout with reduced number of phases to achieve both 1) observation of arterial inflow phase, and 2) better depiction of peripheral arteries at later phases.

Andrew Nicholas Priest¹, Gavin Low¹, Martin John Graves¹, and David John Lomas^1
1Radiology, Addenbrooke's Hospital and University of Cambridge, Cambridge, United Kingdom

Imaging of the thoracic central veins is important for patients with central venous obstruction or with restricted venous access, where contrast-agent administration is difficult. We have developed a subtraction-based non-contrast-enhanced MR angiography method for central vein imaging, using a balanced SSFP readout with dual iMSDE flow-suppression, respiratory navigator gating, spatial saturation, and dual-inversion recovery for fat suppression. Comparisons in six healthy volunteers scored this approach more highly in terms of image quality, artifacts and background suppression, in comparison with alternative versions using spectral fat suppression or no fat suppression, and with breath-hold techniques.

Masanobu Nakamura¹, Masami Yoneyama², Makoto Obara¹, Atsushi Takemura¹, Taro Takahara³, and Marc Van Cauteren^1
1Philips Electronics Japan, Tokyo, Japan, ²Yaesu clinic, Tokyo, Japan, ³Tokai University School of Engineering, Kanagawa, Japan

We hypothesize that vessel-selective time-resolved MRA with the dual vessel-labeling scheme helps with aforementioned issue of selective labeling because the positioning of the inversion slabs with respect to vascular anatomy is different.

Jerome Chaptinel^1,2, Davide Piccini^3,4, Simone Coppo^1,2, Gabriele Bonanno^1,2, and Matthias Stuber^1,2
1Department of Radiology, University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland, ²Center for Biomedical Imaging (CIBM), Lausanne, Switzerland, ³Advanced Clinical Imaging Technology, Siemens Healthcare IM BM PI, Lausanne, Switzerland, ⁴Department of Radiology, University Hospital (CHUV) and University of Lausanne (UNIL) / Center for Biomedical Imaging (CIBM), Lausanne, Switzerland

A novel approach to improve image quality of 1D respiratory self-navigated whole-heart coronary MRI using a KWIC-like technique is presented. Center of k-space radial profiles are weighted according to the breathing position in which they were acquired in order to reduce the impact of large and more complex respiratory displacements. This is possible thanks to the uniform sampling over time and oversampling of the center of k-space of a phyllotaxis 3D radial trajectory in k-space. Such displacement-dependant weighting improves vessel sharpness and CNR without the need of scan prolongation or sophisticated motion correction.

Haining Liu¹, Zechen Zhou², Jinnan Wang³, and Chun Yuan^2,4
1Bioengineering Department, University of Washington, Seattle, WA, United States, ²Bioengineering Department, Tsinghua University, Beijing, China, ³Philips Research North America, NY, United States, ⁴Radiology Department, University of Washington, WA, United States

SNAP can simultaneously detect lumen stenosis and hemorrhage of atherosclerotic plaque with good contrast and resolution. One of its limitations is its inability to differentiate the venous flow from arterial ones. Venous contamination like this will become a challenge to image reviews that focus only on the pathological characteristics of arteries. In this study, we suggest the use of mask generated from two scans with different venous lumen intensity to suppress the venous contamination in regular SNAP. As shown in the in vivo comparison, the venous flow was successfully suppressed while the contrast of arterial lumen was maintained.

Yuki Ohmoto-Sekine¹, Junji Takahashi², Kei Fukuzawa², Atsushi Takemura³, Hiroshi Tsuji¹, and Yasuji Arase^1
1Health Management Center, Toranomon Hospital, Tokyo, Japan, ²Radiology Dept., Toranomon Hospital, Tokyo, Japan, ³Philips Electronics Japan, Tokyo, Japan

Although steady state free procession (SSFP) has been accepted as the method of choice for coronary magnetic resonance angiography (CMRA) at 1.5 T, whether SSFP is suitable for CMRA at a high field strength remains uncertain. We conducted a feasibility study three-dimensional free breathing non contrast CMRA using between SSFP and fast gradient-echo imaging (FGRE) techniques using a 3T commercial scanner. The resulting measurable improvements in the image quality using non-contrast SSFP coronary MRA performed using 3T commercial scanner are likely to lead to more accepted clinical applications.

Cheng Ouyang¹, Aiming Lu¹, Xiangzhi Zhou¹, and Mitsue Miyazaki^1
1Toshiba Medical Research Institute USA, Vernon Hills, IL, United States

As an ECG-gated non-contrast MRA technique, FBI enables the visualization of peripheral arterials by utilizing the physiological signal differences between two cardiac phases: systolic and diastolic phases. It is desirable to depict the vascular inflow effects and to obtain more insightful information on vascular physiology by the time-resolved FBI technique. In this work, we demonstrate the feasibility of an accelerated time-resolved non-contrast FBI MRA technique using compressed sensing, besides, the image reconstruction time was significantly reduced using coil compression.

Jia Ning¹, Shuo Chen¹, Jinnan Wang^2,3, Xihai Zhao¹, Chun Yuan^1,2, and Huijun Chen^1
1Center for Biomedical Imaging Research & Department of Biomedical Engineering, Tsinghua University, Beijing, China, ²Department of radiology, University of Washington, Seattle, WA, United States, ³Philips Research North America, United States

Simultaneous Non-contrast Angiography and intraPlaque hemorrhage (SNAP) imaging has been proposed to image the stenosis of artery and intraplaque hemorrahge (IPH) lesions in the atherosclerotic plaques in one scan Since the SNAP consists a TFE based reference scan for phase sensitive reconstruction, so the scan time is very long. A new proposed optimized fast SNAP contains a low-resolution reference scan is tested on intracranial arteries. Result shows that there is no significant difference in CNRs of SNAP and optimized fSNAP. Also, fSNAP gives a comparable visualization of smaller branches. The scan time of optimized fSNAP is 37.5% less than SNAP.

Kie Tae Kwon¹, Bob S Hu², and Dwight G Nishimura^1
1Electrical Engineering, Stanford University, Stanford, CA, United States, ²Palo Alto Medical Foundation, Palo Alto, CA, United States

A sliding interleaved cylinder (SLINCY) acquisition employs a 3D concentric cylinders trajectory as the readout instead of a 3DFT sequence. Previously, SLINCY was incorporated into a non-contrast-enhanced magnetization-prepared 3D SSFP sequence to improve artery-vein contrast in the lower extremities. However, one of remaining issues for this approach is to suppress the long-T1 fluids, which can otherwise hamper the depiction of arterial blood in SSFP images. In this work, we exploited the thin-slab-scan nature of SLINCY to efficiently add inversion-recovery (IR) to suppress the fluids. We demonstrated that the proposed IR schemes are feasible for SLINCY, which successfully suppressed the fluids.

Robert R. Edelman^1,2, Oisin Flanagan², Shivraman Giri³, and Ioannis Koktzoglou^1,4
1Radiology, NorthShore University HealthSystem, Evanston, IL, United States, ²Radiology, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States, ³Siemens Healthcare, Chicago, IL, United States, ⁴Radiology, University of Chicago Pritzker School of Medicine, Chicago, IL, United States

Quiescent-Inflow single-shot (QISS) MRA is accurate for evaluation of the peripheral arteries. However, the requirement for fat suppression imposes restrictions on pulse sequence design, e.g. necessitating the use of partial Fourier, which degrades spatial resolution and reduces signal-to-noise ratio. We propose the use of an arterial spin labeled version of QISS MRA to overcome these limitations. The technique involves subtraction of two QISS data sets, one with slice-selective saturation and the other with nonselective saturation. QISS ASL improves background suppression compared with standard QISS, enabling visualization of smaller branch vessels than would otherwise be possible. Venous suppression is also improved.

Guoxi Xie^1,2, Bin Sun³, Qingyi Dai⁴, Antonio Hernandez Conte², Xiaoming Bi⁵, Yutaka Natsuaki⁵, Jing An⁶, Reza Arsanjani², Xin Liu¹, Hairong Zheng¹, Zhanming Fan⁴, Daniel Berman², Debiao Li², and Zhaoyang Fan^2
1Shenzhen Key Lab for MRI, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China, ²Cedars Sinai Medical Center, Los Angeles, CA, United States, ³Union Hospital, Fujian Medical University, Fujian, China, ⁴Radiology Department, Anzhen Hospital, Beijing, China, ⁵Siemens Healthcare, Los Angeles, CA, United States, ⁶MR Collaborations NE Asia, Siemens Healthcare, Beijing, China

3D dark-blood MRI techniques have shown great potential in coronary plaque burden assessment. However, substantial variability in quantification could result from superficial calcification that often mimics part of lumen because of its low signal. Recent work shows that gray-blood contrast can help separate superficial calcification from lumen. Thus, the purpose of this work was to develop a 3D coronary dark-blood interleaved with gray-blood (cDIG) MRI technique to improve the visualization and quantification of coronary plaque. In vivo experiment results demonstrated that dual contrasts were simultaneously acquired using the proposed method without compromising dark-blood contrast and scan time.

Jin Liu¹, Niranjan Balu¹, Daniel S. Hippe¹, Marina S. Ferguson¹, Vanesa Martinez-Malo¹, J. Kevin DeMarco², David C. Zhu², Hideki Ota³, Jie Sun¹, William S. Kerwin¹, Thomas S. Hatsukami¹, and Chun Yuan^1
1University of Washington, Seattle, WA, United States, ²Michigan State University, MI, United States, ³Tohoku University Hospital, Sendai, Japan

Intraplaque hemorrhage (IPH), a critical factor in atherosclerosis destabilization, can be detected as a hyperintense area in magnetization-prepared rapid acquisition gradient-echo (MP-RAGE) MR images. Currently the threshold to define hyperintensity is arbitrarily chosen relative to surrounding muscle without histology validation.. In this study, optimized thresholds for carotid IPH detection in MP-RAGE images were obtained using histology as golden standard, providing an automatic and effective IPH detection method. Furthermore, results showed that the IPH areas measured in MRI using the optimized thresholds highly correlated with those measured in histology.

Yunduo Li¹, Lirong Yan², Mayank Jog², Robert Smith², Karen Ying³, Rui Li⁴, Chun Yuan⁴, and Danny JJ Wang^2
1Department of Biomedical Engineering, Tsinghua University, Beijing, Beijing, China, ²Neurology, UCLA, CA, United States, ³Department of Engineering Physics, Tsinghua University, Beijing, China, ⁴Center for Biomedical Imaging Research, Tsinghua University, Beijing, China

A novel method which employs the velocity-selective RF pulse to suppress the signal from flowing blood is presented and a design example is shown. Simulation results demonstrate that the velocity-selective profile of the designed pulse meets the demand of vessel wall imaging. Phantom and in-vivo studies verified the designed pulse can invert flowing spins of high velocity and leave the static spins undisturbed. All results imply that the pulse is potentially suitable for blood suppression in vessel wall imaging. The method enables the pulse designer to trade off among important parameters such as pulse duration, cut-off velocity and pass-band ripples.

Jinnan Wang¹, Michael Schär², Chun Yuan³, and Peter Börnert^4
1Philips Research North America, Seattle, WA, United States, ²Philips Healthcare, Cleveland, Ohio, United States, ³University of Washington, Seattle, WA, United States, ⁴Philips Research Europe, Hamburg, Hamburg, Germany

Motion sensitized driven equilibrium (MSDE) was proposed as an effective way to achieve black blood vessel wall imaging. With the gaining popularity of large coverage 3D vessel wall imaging, banding artifacts can be frequently found on existing MSDE images. In this abstract, an inhomogeneity insensitive MSDE (i2MSDE) was proposed for robust large coverage vessel wall imaging. The signal improvement was found on simulation, phantom experiments and also validated in vivo. i2MSDE is a promising technique for large coverage black blood imaging.

Shuo Chen¹, Xihai Zhao¹, Jia Ning¹, Jinnan Wang^2,3, Chun Yuan^1,2, and Huijun Chen^1
1Center for Biomedical Imaging Research & Department of Biomedical Engineering, School of Medicine, Beijing, China, ²Department of radiology, University of Washington, Seattle, WA, United States, ³Philips Research North America, Briarcliff Manor, NY, United States

The Simultaneous Non-contrast Angiography and intra-Plaque hemorrhage (SNAP) sequence has been proposed for imaging both luminal stenosis and intraplaque hemorrhage in subjects with carotid atherosclerosis in one scan. Full-resolution reference scan in traditional SNAP sequence will double the acquisition time. To shorten the scan time, we propose a new fSNAP sequence with interleaved full-resolution inversion recovery scan and low-resolution reference scan for carotid atherosclerotic disease evaluation. Total scan time is shortened by 37.5% without negatively impacting MRA quality and intraplaque hemorrhage detection, suggesting that fSNAP proposed in this study might be an alternative method for carotid atherosclerotic disease evaluation.

Shuo Chen¹, Xihai Zhao¹, Jinnan Wang^2,3, Chun Yuan^1,2, and Huijun Chen^1
1Center for Biomedical Imaging Research & Department of Biomedical Engineering, School of Medicine, Beijing, China, ²Department of radiology, University of Washington, Seattle, WA, United States, ³Philips Research North America, Briarcliff Manor, NY, United States

Peripheral arterial disease (PAD) is a common and ‘silent’ disorder that usually affects 3% to 7% of people in the general population. Femoral artery is a major target vascular bed of PAD. In this study we validated the simultaneous non-contrast angiography and intraplaque hemorrhage (SNAP) sequence on femoral artery imaging. Both angiography and vessel wall images can be well depicted.

Wei Zhang¹, Jie Sun², Bin Zhou¹, Jianrong Xu¹, Daniel S Hippe², Thomas S Hatsukami², and Chun Yuan^2
1Department of Radiology, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, Shanghai, China, ²Department of Radiology, University of Washington, Seattle, WA, United States

Cardiovascular complications, which result from atherosclerotic lesions, are now the leading cause of mortality in patients with SLE. Subclinical atherosclerosis can be documented in 30% to 40% of patients. An early diagnosis of subclinical AS in young patients with SLE is preferable for a more effective treatment that may reduce the development of major cardiovascular complications. In this study we focus on vessel wall changes on MR imaging to detect early subclinical atherosclerosis lesion in SLE patients and try to find out the risk factors associated with atherosclerosis in these women.

Niranjan Balu¹, Haining Liu¹, Shuo Chen², Huijun Chen², Jinnan Wang³, Zechen Zhou¹, and Chun Yuan^1
1Radiology, University of Washington, Seattle, WA, United States, ²Biomedical Engineering, School of Medicine,Tsinghua University, Beijing, China, ³Philips Research North America, Briarcliff Manor, New York, United States

Multicontrast MRI is currently used to identify high-risk atherosclerotic plaque components. We propose a dual contrast vessel wall MRI sequence to identify four major high-risk features: plaque burden, stenosis, intraplaque hemorrhage and juxtaluminal calcification by extending the phase-sensitive reconstruction of a recently proposed vessel wall MRI sequence (SNAP) to include a proton density black-blood weighting. We demonstrate that combined review of bright-blood, gray-blood and black-blood images obtained from a single five minute acquisition can identify high-risk plaque in patients with atherosclerotic carotid plaque.

Wei Zhang¹, Jie Sun², Bin Zhou¹, Jianrong Xu¹, Daniel S Hippe², Huijun Chen³, Thomas S Hatsukami², and Chun Yuan^2
1Department of Radiology, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, Shanghai, China, ²Department of Radiology, University of Washington, Seattle, WA, United States, ³Department of Biomedical Engineering, Tsinghua University, Beijing, China

Patients with systemic lupus erythematosus (SLE) have markedly increased risk of carotid atherosclerosis. In this preliminary study, we tried to use MR imaging and post-processing software to examine any early abnormalities in fine structures of carotid vessel wall, including the wall thickening, different enhancement and signal intensity changes in patients with SLE by comparing them to age- and sex-matched controls. MR had a great success in analysis plaque components, while we want to show that MR also can be a useful way in predicting and measuring the early subclinical atherosclerosis lesion in SLE patients before their plaque formation.

Harm Nieuwstadt¹, Zaid Kassar^1,2, Aad van der Lugt², Ton van der Steen^1,3, Marcel Breeuwer^4,5, and Frank Gijsen^1
1Biomedical Engineering, Erasmus MC, Rotterdam, Zuid-Holland, Netherlands, ²Radiology, Erasmus MC, Rotterdam, Zuid-Holland, Netherlands, ³Imaging Science and Technology, Delft University of Technology, Delft, Zuid-Holland, Netherlands, ⁴Philips Healthcare, Best, Noord Brabant, Netherlands, ⁵Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Noord Brabant, Netherlands

We employed MRI simulations to quantify the influence of slice thickness (i.e. voxel anisotropy in the slice-select direction) for carotid MRI of atherosclerotic plaques. We simulated a clinically applied 2D T1 weighted sequence and varied the slice thickness. Five realistic 3D plaque models were created from histological data. We found significant improvements in FC thickness measurement error when using thinner slices, but less to no improvements in LRNC size measurements. Our study indicates that for carotid MRI, the use of anisotropic voxels can be permitted for specific applications. However, the use of thinner slices improves minimum FC thickness measurements.

Haining Liu¹, Zechen Zhou², Jinnan Wang³, Shuo Chen², Balu Niranjan⁴, and Chun Yuan^2,4
1Bioengineering Department, University of Washington, Seattle, WA, United States, ²Bioengineering Department, Tsinghua University, Beijing, China, ³Philips Research North America, NY, United States, ⁴Radiology Department, University of Washington, WA, United States

Lipid core is an important indicator for high-risk atherosclerotic plaque. Diffusion weighted imaging has great potential for lipid core imaging without gadolinium injection. The DIR based diffusion weighted black blood imaging (BB) scheme required long preparation time and thus has low time efficiency. iMSDE is a BB sequence which has advantages in regions with complex and slow flow without long presaturation time. In this study, we investigate the diffusion weighted iMSDE (DiMSDE) scheme by introducing appropriate m1 into the diffusion gradients. Experiments shows this scheme is effective for both diffusion weighted imaging and black blood imaging.

Anirudh Damughatla¹, William Kenyhercz², Brian Raterman², Peter Wassenaar², Richard White^1,3, and Arunark Kolipaka^1,3
1Biomedical Engineering, The Ohio State University, Columbus, Ohio, United States, ²Radiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, United States, ³Radiology and Internal Medicine, Division of Cardiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, United States

Arterial stiffness is an important indicator for diagnosing many cardiovascular diseases. It has been shown that arterial stiffness varies across the cardiac cycle and has different effects in disease progression during systole when compared to diastole. In-vivo aortic magnetic resonance elastography (MRE) was performed in a 3T-MRI scanner on 4 volunteers aged between 20-33 years to determine the stiffness of the aorta across the cardiac cycle. Initial results demonstrate the feasibility and reproducibility of the MRE-derived stiffness and also suggest higher stiffness values at end-systole compared to end-diastole.

Guan Wang^1,2, M. Arcan Erturk^1,2, Shashank Sathyanarayana Hegde², and Paul A. Bottomley^1,2
1Electrical & Computer Engineering, Johns Hopkins University, Baltimore, MD, United States, ²Russell H. Morgan Dept. of Radiology & Radiological Sciences, Johns Hopkins University, Baltimore, MD, United States

The ability to characterize atheroma components is central to assessing the status of vessel disease, and its progression and response to intervention. High-field intravascular MRI (IVMRI) offers the potential for assessing T₁, T₂, proton density and lipid burden in healthy and diseased vessels at a resolution approaching 100µm. Here, results from multi-parametric, 200µm-resolution intravascular IVMRI employing a novel ‘Tri-Flip-Angle’ method are presented. T₁, T₂ and proton density are mapped with B₁-self-correction in only four acquisitions, while the lipid pool is imaged by Dixon (or selective saturation) techniques in human iliac artery specimens.

Xiaoying Cai¹, Feng Huang², Tingting Wu³, Kui Ying⁴, Chun Yuan³, and Huijun Chen^3
1Biomedical Engineering, University of Virginia, Charlottesville, Virginia, United States, ²Philips Healthcare, Gainesville, FL, United States, ³Center for Biomedical Imaging Research, Beijing, China, ⁴Department of Engineering Physics, Tsinghua University, Beijing, China

We adopted several temporal acceleration methods to investigate the feasibility of accelerating black blood vessel wall DCE-MRI in small animal with early lesion in the abdominal artery. Both numerical simulation data and in-vivo data were adopted in this study. The results showed that the higher temporal resolution due to the acceleration would provide more accurate kinetic parameter evaluation without sacrificing much image quality.

Guoxi Xie^1,2, Xiaoming Bi³, Jing An⁴, Xin Liu¹, Hairong Zheng¹, Debiao Li², and Zhaoyang Fan^2
1Shenzhen Key Lab for MRI, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China, ²Biomedical Imaging Research Institute, Cedars Sinai Medical Center, Los Angeles, CA, United States, ³Siemens Healthcare, Los Angeles, CA, United States, ⁴MR Collaborations NE Asia, Siemens Healthcare, Beijing, China

Peripheral artery disease (PAD) is a slow and progressive circulation disorder which not only causes pain and disability. Flow independent dark-blood 3D MRI is suitable for peripheral artery vessel wall imaging with large coverage. Previous studies have proposed SPACE and MERGE for 3D peripheral artery vessel wall imaging. However, SPACE still needs long scan time while MERGE is sensitive to B0 inhomogeneous. In this work, a 3D DANTE-Prep dark-blood GRE sequence was developed for peripheral artery vessel wall imaging. It allows screening bilateral 30-cm-long peripheral arteries within 4 minutes with isotropic high spatial resolution (0.72×0.72×0.72 mm3).

Taku Yoneyama¹, Jie Sun¹, Daniel Hippe¹, Dongxiang Xu¹, William Kerwin¹, Thomas Hatsukami¹, and Chun Yuan^1
1University of Washington, Seattle, WA, United States

Automatic plaque segmentation algorithms have been proposed to be helpful for large-scale and/or multicenter studies. Yet few data are their performance in real-world applications. In this study, by using a prospective cohort study with baseline and follow-up imaging, quantitative measurements on plaque tissue composition including calcification and lipid-rich necrotic core as analyzed by an automatic classifier were compared to expert human review. Results showed excellent correlation between MEPPS and manual review in analyzing compositional volumes with images of a single time point, and moderate to good correlation in analyzing compositional changes with images of multiple time points.

Chengcheng Zhu¹, Andrew J Patterson¹, Jonathan H Gillard¹, and Martin J Graves^1
1Department of Radiology, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom

Blood suppression is essential for black blood vessel wall imaging, and unsuppressed intra-luminal blood leads to plaque mimicking artefacts。This study aims to evaluate the efficiency of DANTE blood suppression and SNR performance in 2D T1 and T2 weighted FSE sequences and 3D variable flip angle FSE (CUBE, GE Healthcare) sequence in comparison with DIR and iMSDE preparation.

Iulius Dragonu¹, Julia Geiger², Bernd Jung¹, Marco Vicari¹, Jürgen Hennig¹, and Ute Ludwig^1
1Radiology - Medical Physics, University Medical Center Freiburg, Freiburg, Germany, ²Radiology, University Medical Center Freiburg, Freiburg, Germany

Giant cell arteritis (GCA), also known as temporal arteritis or Horton’s disease, is a granulomatous vasculitis of large- and medium-sized arteries. The disease usually concerns the superficial cranial arteries with predominance of the temporal arteries. However, GCA is not necessarily localized specifically to the temporal or cranial arteries. Involvement of extracranial arteries, mainly the aorta with its branches can also occur. In this work, we present a novel high resolution multi-contrast MR protocol allowing the depiction of vascular geometry with large coverage including the aorta and the subclavian arteries.

Masataka Sugiyama¹, Yasuo Takehara¹, Yang Wang¹, Shuhei Yamashita¹, Naoki Ooishi¹, Marcus Alley², Tetsuya Wakayama³, Atsushi Nozaki³, Hiroyuki Kabasawa³, and Harumi Sakahara^1
1Radiology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan, ²Radiology, Stanford Unviersity School of Medicine, Palo Alto, CA, United States, ³Applied Science Laboratory Asia Pacific, GE Healthcare Japan, Hino, Tokyo, Japan

26 consecutive patients who were examined both with 4D-Flow and CT were enrolled in the study. 4D-Flow was performed following 3D Gd-MRA. WSS and OSI of the aortic wall were calculated. Based on the CT findings, 10 atherosclerosis and 16 non-atherosclerosis in the lower abdominal aorta were subdivided. Multivariate logistic analysis showed that Diastolic WSS (p = 0.0224) and OSI (p = 0.0172) were independent determinant for the presence of atherosclerosis. Hemodynamic abnormalities reflected by low diastolic WSS and high OSI are considered to be potential determinants of lower abdominal atherosclerosis. 4D-Flow with an aid of flow analysis software can provide these hemodynamic parameters objectively.

Anita A. Harteveld¹, Nerissa P. Denswil², Jeroen C.W. Siero¹, Jaco J.M. Zwanenburg^1,3, Aryan Vink⁴, Wim G.M. Spliet⁴, Nikki Dieleman¹, Peter R. Luijten¹, Mat J.A.P. Daemen², Jeroen Hendrikse¹, and Anja G. van der Kolk^1
1Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands, ²Department of Pathology, Academic Medical Center, Amsterdam, Netherlands, ³Image Science Institute, University Medical Center Utrecht, Utrecht, Netherlands, ⁴Department of Pathology, University Medical Center Utrecht, Utrecht, Netherlands

Intracranial atherosclerosis is one of the most important causes of ischemic stroke and transient ischemic attack (TIA). In the recent years, several intracranial vessel wall imaging techniques using (ultra)high-field magnetic resonance imaging (MRI) have emerged for the evaluation of atherosclerotic vessel wall lesions. However, a thorough correlation of MRI results of intracranial plaques with histopathology is still lacking. Therefore, a multi-contrast ultrahigh-resolution MRI protocol at 7T was developed for ex vivo quantitative intracranial atherosclerotic plaque characterization. Together with the results of the corresponding histological data, a proper correlation of the MRI findings with the underlying pathology may be performed.

Chengcheng Zhu¹, Andrew J Patterson¹, Jonathan H Gillard¹, and Martin J Graves^1
1Department of Radiology, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom

High spatial-resolution multi-contrast MRI of the carotid artery vessel wall can visualize high-risk morphological features of plaques in vivo and help patient risk stratification. The use of a gadolinium-based contrast agent improves the accuracy of plaque characterization. In this study we aim to evaluate DANTE in contrast-enhanced MRI of carotid artery wall using 2D T1w FSE and 3D FSE (CUBE, GE Healthcare) in patients. To our knowledge this is the first study applying DANTE post-contrast.

Xiaoqing Hu^1,2, Lei Zhang¹, Huabin Zhu³, Xiao Chen¹, Yiu-cho Chung^1,2, Xin Liu^1,2, Hairong Zheng^1,2, and Ye Li^1,2
1Shenzhen Institutes of Advanced Technology of Chinese Academy of Sciences, Shenzhen, Guangdong, China, ²Shenzhen Key Laboratory for MRI, Shenzhen, Guangdong, China, ³Suzhou Medcoil Healthcare Co.,Ltd, Suzhou, Jiangsu, China

In this work, we propose an approach to construct the 20-channel head/neck coil with extended longitude coverage and high SNR by combining a commercial 12-channel head array and adedicated 8-channel carotid array in convenient fashion. The coupling effects are compensated by accounting for the noise correlation matrix in the reconstruction method. Both phantom and in-vivo experiment results show that the proposed array is capable to provide a large coverage from carotid to brain vessels with high SNR and good parallel imaging performance, which will benefit arterial disease diagnosis.

Kei Tsukamoto¹, Takayuki Masui¹, Motoyuki Katayama¹, Kimihiko Satoh¹, Kenichi Mizuki¹, Masayoshi Sugimura¹, Harumi Sakahara², Mitsuharu Miyoshi³, and Hiroyuki Kabasawa^3
1Seirei Hamamatsu General Hospital, Hamamatsu, Shizuoka, Japan, ²Hamamatsu Universtiy of Medicine, Hamamatsu, Shizuoka, Japan, ³GE Health Care Japan, Hino, Tokyo, Japan

An investigational version of fat-suppressed black blood (BB) 3D FSE T1WI (CUBE T1) with imaging coverage of the neck and head and acceptable scan time might be useful in assessment of stenotic lesion in the carotid arteries. The purpose was to evaluate the detection of the stenotic lesion in proximal internal carotid artery using BB imaging with CUBE T1 in comparison of MRA with 3D TOF. This technique can be better to detect the stenotic lesions and the early stage of atherosclerotic lesions than MRA.

Andrew Swift¹, Dave Capener², Helen Marshall², Charlie Elliot³, Robin Condliffe³, David Kiely³, and Jim Wild^2
1Academic Unit of Radiology, University of Sheffield, Sheffield, S.Yorkshire, United Kingdom, ²Academic Unit of Radiology, University of Sheffield, S.Yorkshire, United Kingdom,³Sheffield Pulmonary Vascular Disease Unit, Sheffield Teaching Hospitals NHS Trust, S.Yorkshire, United Kingdom

There is growing evidnence that dynamic contrast enhanced (DCE) MR imaging measurements relate to invasive haemodynamics and have clinical utility in the assessment of patients with pulmonary hypertension. This study develops the role of DCE MR imaging in this patient group identifying independent associations with key prognostic indicators such as right ventricular characteristics and invasive haemodynamics measurements.

Bram Schermers, BSc^1,2, Rachel Kleinloog, MD¹, Bon H Verweij, MD, PhD¹, Ynte M Ruigrok, MD, PhD¹, Peter R Luijten, PhD³, Fredy Visser^3,4, Luca Regli, MD, PhD^1,5, Gabriël JE Rinkel, MD¹, and Jaco J Zwanenburg, PhD^3
1Brain Center Rudolf Magnus, Department of Neurology and Neurosurgery, University Medical Center Utrecht, Utrecht, Utrecht, Netherlands, ²Faculty of Science and Technology, Department of Technical Medicine, University of Twente, Enschede, Twente, Netherlands, ³Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands, ⁴Philips Healthcare, Best, Netherlands, ⁵Department of Neurosurgery, University Hospital Zürich, Zürich, Switzerland

Currently, good predictors for the prediction of intracranial aneurysm rupture risk are lacking. Therefore, we assessed the feasibility of measuring intracranial aneurysm volume pulsation at 7.0 tesla MRI, and quantified the accuracy of these measurements. Ten aneurysms were imaged and a phantom-based accuracy study was performed. We found that noise and intensity fluctuations due to the inflow of blood have a profound influence on the accuracy. Though aneurysm pulsation measurement is feasible in patients, the estimated inaccuracy is of similar size as the observed volume pulsations, indicating the need for further improvement of the image quality protocol and analysis.

Hikari A. I. Yoshihara^1,2, Jessica A. M. Bastiaansen^2,3, Corinne Berthonneche⁴, Arnaud Comment^2,3, and Juerg Schwitter^5
1Division of Cardiology, Lausanne University Hospital, Lausanne, Switzerland, ²Center for Biomedical Imaging (CIBM), Lausanne, Switzerland, ³Institute of Physics of Biological Systems, Ecole Polytechnique Fédérale de Lausanne, Switzerland, ⁴Cardiovascular Assessment Facility, Lausanne University Hospital, Switzerland, ⁵Division of Cardiology and Cardiac MR Center, Lausanne University Hospital, Switzerland

An open-chest rat model of myocardial ischemia was adapted to study in real time, using hyperpolarized 13C MRS, the changes in cardiac metabolism associated with short 15 minute periods of ischemia. Immediately following ischemia, a decrease in the conversion of infused hyperpolarized pyruvate to bicarbonate was observed relative to its conversion to lactate, consistent with the expected decrease in pyruvate dehydrogenase activity and increase in lactate concentration. This study establishes an experimental platform for further studies with other hyperpolarized 13C metabolic probes.

Peter Speier¹, Andreas Greiser¹, Christoph Guetter², and Marie-Pierre Jolly^2
1Siemens AG Healthcare Sector, Erlangen, Germany, ²Imaging and Computer Vision, Siemens Corporation, Corporate Technology, Princeton, NJ, United States

Double-triggered stimulated-echo EPI with monopolar diffusion encoding is a robust method for measuring diffusion in the left ventricle of the heart. To minimize contamination of diffusion results by cardiac motion, encoding must take place at one of two strain sweet spots, i.e., time points in the cardiac cycle where cardiac strain assumes its average value. We demonstrate that sweet spot positions of left-ventricular blood volume-time curves, as determined by automated segmentation algorithms, are in good agreement with strain sweet spot positions of mid-ventricular short axis slices, thus eliminating the need for additional strain measurements and analysis for measurement planning.

T. Stan Gregory¹, Ehud J Schmidt², Shelley Hualei Zhang², and Zion Tsz Ho Tse^1
1University of Georgia, Athens, GA, United States, ²Brigham and Women's Hospital, Boston, MA, United States

Blood plasma electrolytes ejected into the aorta during early systole interact with the strong magnetic field of the MR scanner to produce a Magnetohydrodynamic-induced voltage (VMHD). Electrocardiograms (ECG) recorded in the presence of this magnetic field are overlaid with VMHD. Resultant intermittent QRS detection is conventionally compensated for by Vectorcardiogram (VCG) based gating approaches. A multiple channel ECG-based cross-correlation algorithm, the 3DQRS, has been recently developed to achieve increased sensitivity in QRS detection at high field strengths. A quantitative comparison of the 3DQRS method and a VCG-based approach at varying MRI field strengths was performed as an assessment of robustness.

Erpeng Dai¹, Zhe Zhang¹, Juan Wei², Xihai Zhao¹, Li Dong³, Chun Yuan^1,4, and Hua Guo^1
1Center for Biomedical Imaging Research, Tsinghua University, Beijing, Beijing, China, ²Philips Research China, Beijing, China, ³Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, Beijing, China, ⁴Department of Radiology, University of Washington, Seattle, WA, United States

In this study, a MSDE prepared spoiled gradient (SPGR) sequence was proposed to acquire black blood cine images of common carotid arteries (CCA) and investigate its dynamics quantitatively. Parameters related to dynamics of CCAs, including lumen areas, wall areas and distension were calculated and analyzed. Comparisons between black blood images and bright blood images were made. Based on this method, artery lumen dynamics and wall dynamics can be evaluated quantitatively, both of which may be valuable for investigating biomechanical and functional properties of the vasculature, monitoring vessel stiffness changes, and diagnosing related cardiovascular diseases.

Rupa Krishnaswamy¹, Gary Gerstenblith¹, Sahar Soleimanifard², Michael Schar³, Matthias Stuber⁴, and Robert G Weiss^5
1Medicine, Johns Hopkins University, Baltimore, MD, United States, ²Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States, ³Radiology, Johns Hopkins University, Baltimore, MD, United States, ⁴Radiology, Centre Hospitalier Univ Vaudois, Lausanne, Switzerland, Switzerland, ⁵Medicine, Radiology, Johns Hopkins Univ, MD, United States

We have used non-invasive 3T MRI with isometric handgrip exercise (IHE) to evaluate endothelial function of two physiologically different vascular beds (coronary and systemic) in healthy subjects and patients with coronary artery disease (CAD). Using this methodology, endothelial-dependent response of coronary and systemic vasculature can be assessed in the same person, and sometimes within the same MRI acquisition. We have confirmed that coronary vasodilation does not occur in patients with CAD, and demonstrated that the internal mammary artery exhibits a greater degree of vasodilation with IHE than the right coronary artery in patients with CAD.

Rik PM Moonen^1,2, Gustav J Strijkers^1,2, Abdallah Motaal^1,2, Rolf Lamerichs^2,3, Muhammed Yildirim⁴, Erica Aussems-Custers^2,3, Holger Gruell^1,3, Martijn Wolters⁵, Eline ME Kooi⁵, Christoph Jacoby⁶, Ulrich Flögel⁶, and Klaas Nicolay^1,2
1Biomedical Engineering/Biomedical NMR, Eindhoven University of Technology, Eindhoven, Netherlands, ²Center for Imaging Research & Education (CIRE), Eindhoven, Netherlands, ³Philips Research, Eindhoven, Netherlands, ⁴Philips Healthcare, Best, Netherlands, ⁵Department of Radiology, Maastricht University Medical Center (MUMC+), Maastricht, Netherlands, ⁶Institut für Molekulare Kardiologie, Heinrich-Heine-Universität, Düsseldorf, Germany

Two accelerated ¹⁹F MRI sequences, Multiple Chemical Shift Selective RARE (MCSS-RARE) and Fluorine ultrafast Turbo Spectroscopic Imaging (FuTSI) were compared for their ability to image multiple ¹⁹F resonances of perfluorocarbon (PFC) emulsions. MCSS-RARE is spectrally selective, whereas FuTSI has a spectral read-out. The MCSS-RARE sequence proved superior in terms of scan speed and SNR. Both sequences enabled spectral imaging of ¹⁹F resonances in liver and spleen of ApoE-/- mice injected with PFOB emulsion, but failed to visualize PFOB accumulation in plaques in vivo. Ex vivo MCSS-RARE imaging did reveal ¹⁹F resonances at major plaque sites.