1885.     Impact of Timing and Dose of Isosorbide Dinitrate Administration on Coronary MRI

Peng Hu¹, Dana C. Peters¹, Kraig V. Kissinger¹, Beth Goddu¹, Lois Goepfert¹, Warren J. Manning¹, Reza Nezafat¹

¹Beth Israel Deaconess Medical Center, Boston, MA, USA

In this study, we investigate the impact of sublingual isosorbide dinitrate on SNR, vessel diameter, vessel sharpness and overall image quality in coronary MRI as a function of time, dose and imaging sequence. Isosorbide dinitrate improves coronary MRI SNR by 20% for both GRE and SSFP imaging. Compared to 2.5mg dose, the 5mg dose results in higher SNR, comparable vasodilation that occurs earlier and with greater vessel sharpness scores. The 5mg dose is therefore preferred.

                  1886.     Feasibility of Whole-Heart Coronary MRA on 3 Tesla Using Ultrashort-TR SSFP VIPR

Jingsi Xie¹, Peng Lai¹, Himanshu Bhat¹, Debiao Li¹

¹Departments of Radiology and Biomedical Engineering, Northwestern University, Chicago, IL, USA

To perform Whole-Heart Coronary MRA on 3 Tesla Using SSFP technique with VIPR trajectory to reduce TR

                  1887.     Coronary Artery Imaging at 3T: A 32- Versus 6-Channel Cardiac Coil Comparison

Andrea J. Wiethoff^1,2, John J. Totman^1,3, Sergio A. Uribe Arancibia^1,3, Tobias Schaeffter^1,3, Rene M. Botnar^1,3

¹Division of Imaging Sciences, King's College London, London, UK; ²Philips Healthcare, Reigate, UK; ³NIHR Biomedical Research Centre at Guy’s & St Thomas’ Hospital and King’s College London

In this study we sought to investigate the benefit of a new 32-channel cardiac coil for whole-heart and targeted coronary artery imaging at 3T. Exploitation of 32-channel coil technology can reduce the time required for coronary artery imaging while maintaining an acceptable image quality.

                  1888.     Coronary MR Angiography in Children During Systole and Diastole Using a Dual Cardiac Phase Scan of the Whole Heart

Sergio Andres Uribe Arancibia¹, Israel Valverde², Philipp Beerbaum¹, Aaron Bell¹, Rene Botnar¹, Reza Razavi¹, Tobias Schaeffter¹, Gerald Greil¹

¹Division of Imaging Sciences, King's College London, London, UK; ²Cardiologia Infantil, Hospital Virgen del Rocio, Sevilla, Spain

In this abstract we will investigate the feasibility of dual phase cardiac whole heart MRI to obtain Coronary Magnetic Resonance Angiography (CMRA) at end-systole and mid-diastole in children with Congenital Heart Diseases (CHD). This technique allows optimal coronary artery visualization by choosing the best rest period of the heart without any scan time penalty.

                  1889.     Contrast-Enhanced Whole-Heart Coronary MRA at 3T Using Gradient Echo Interleaved EPI and Single Dose of Gd-BOPTA

Himanshu Bhat¹, Sven Zuehlsdorff², Renate Jerecic², Debiao Li¹

¹Radiology and Biomedical Engineering, Northwestern University, Chicago, IL, USA; ²Siemens Medical Solutions, Chicago, IL, USA

A gradient echo interleaved EPI (GRE-EPI) sequence was optimized for contrast-enhanced whole-heart coronary MRA at 3T using slow infusion of a single dose of Gd-BOPTA (Multihance, Bracco). In volunteers, all the major coronary arteries were clearly depicted in an average scan time of 3 minutes. This represents more than a factor of 2 reduction in both the scan time and contrast dose from previous studies. Single dose reduces the risks associated with contrast media as compared to double dose.

                  1890.     ContinuousLy Adaptive Windowing Strategy (CLAWS): An Automatic Technique for Achieving the Best Possible Respiratory Efficiency Regardless of the Breathing Pattern.

Permi Jhooti¹, Jennifer Keegan², David Firmin²

¹Radiological Physics, University Hospital Basel, Basel, Switzerland; ²CMR Unit, Royal Brompton Hospital, London, UK

An automatic technique is presented for respiratory-gated 3D coronary MRA which acquires the data in the fastest possible time regardless of any changes in the breathing pattern (p = ns). No manual window is required as the technique, CLAWS, assumes all possible window combinations are relevant and acquires all data. Further, the scan may be aborted after an initial pass and an image reconstructed. CLAWS is shown to be significantly quicker than standard gating techniques with guaranteed image acquisition.

                  1891.     Model-Free Slice Following Using the Cardiac Fat Navigator: Enhanced Gating Efficiency for 3D SSFP Coronary Magnetic Resonance Angiography

Pascal Spincemaille¹, Thanh Dang Nguyen¹, Martin Prince¹, Yi Wang¹

¹Radiology, Weill Medical College of Cornell University, New York, NY, USA

Coronary MRA routinely uses a diaphragm navigator combined with slice tracking to enhance navigator gating efficiency. The actual heart displacement is calculated from a linear model. Any breakdown in this correlation (such as in the case of hysteresis), degrades image quality. The cardiac fat navigator, which tracks epicardial fat, provides a direct measure of heart motion so that slice tracking does not require correction or calibration factors as is needed when cardiac motion is extrapolated from diaphragm motion. In this study, the slice tracking cardiac fat navigator with an enlarged gating window was found to improve scanning efficiency without affecting image quality.

                  1892.     Feasibility Study of Automatic Breathing Level Tracking and Active Breathing Level Control Methods for Whole-Heart Magnetic Resonance Coronary Angiography (WH MRCA)

Shigehide Kuhara¹, Satoru Hasebe², Seiko Mizuno², Masatoshi Hyodo², Takahiro Yamamoto², Sachiko Ueoku¹, Ayako Ninomiya¹, Hirofumi Anno³

¹MRI Systems Division, Toshiba Medical Systems Corporation, Otawara-shi, Tochigi, Japan; ²Okazaki City Medical Association Public Health Center, Okazaki-shi, Aichi, Japan; ³Radiological Technology, School of Health Sciences, Fujita Health University, Toyoake-shi, Aichi, Japan

We have developed an automatic breathing level tracking method that tracks the changes in the patient's breathing level and an active breathing level control method that can control the patient's breathing pattern by applying external pressure to the patient's abdomen. The active breathing level control method can be used to control the patient's breathing level and reduce the scan time and also improve image quality when the tracking range of the automatic tracking method is controlled appropriately. It is therefore concluded that these methods can be very helpful in clinical WH MRCA studies.

                  1893.     On-Resonant Binomial Pulse Preparation for Magnetization Transfer Contrast Enhanced Coronary Vein Imaging

Christian Torben Stoeck^1,2, Dana C. Peters¹, Yuchi Han¹, Kraig V. Kissinger¹, Beth Goddu¹, Lois Goepfert¹, Warren J. Manning^1,3, Sebastian Kozerke², Reza Nezafat¹

¹Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard, Boston, MA, USA; ²Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland; ³Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA

Off-resonance RF irradiation for magnetization transfer contrast has recently been shown to create an appropriate amount of contrast in coronary vein imaging. In this study, we sought to investigate the use of an optimal binomial pulse for on-resonant magnetization transfer sequences. In the lower range of applied flip angles the on-resonant RF irradiation showed to be superior to off-resonant irradiation, which might be of benefit if the amount of RF energy deposition in tissue is limited.

                  1894.     Impact of Preparation Phases on Vessel Wall Imaging Using Spiral Image Acquisition at 3 Tesla

Miriam Wilhelmina Lagemaat¹, Markus Henningsson², Peter Boernert³, Jouke Smink⁴, Andrea J. Wiethoff², Rene M. Botnar²

¹Dep. of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands; ²NIHR Biomedical Research Centre at Guy's & St Thomas' Hospital and King's College London, London, UK; ³Philips Research, Hamburg, Germany; ⁴Philips Healthcare, Best, Netherlands

The availability of high field 3T clinical scanners enables higher resolution coronary vessel wall imaging. The use of more SNR-efficient spiral sequences together with the local inversion technique would combine the advantage of high field MRI with the ability of 3D imaging of the coronary vessel wall. The main challenge to be overcome is the increased field inhomogeneity at 3T. Therefore the of correct f0 and shim values are of high importance. In this study we sought to optimize the sequence for 3T and investigated the impact of the f0 and shimming trigger delay on image quality.

                  1895.     Robust and Time-Efficient Black Blood Coronary Vessel Wall Imaging at 3T Using IMSDE

Jinnan Wang¹, Suzanne Gerretsen², Jeffrey H. Maki¹, Daniel Herzka³, Baocheng Chu¹, Vasily L. Yarnykh¹, Chun Yuan¹, Tim Leiner²

¹University of Washington, Seattle, WA, USA; ²Maastricht University, Maastricht, Netherlands; ³School of Medicine, Johns Hopkins University, Baltimore, MD, USA

The coronary arteries are a frequent site for atherosclerosic disease. The aim of this study was to examine the feasibility of a recently proposed black-blood technique, improved motion-sensitized driven equilibrium (iMSDE) sequence, for time-efficient in vivo human coronary vessel wall imaging.

                  1896.     Coronary Vessel Wall Thickness: Validation of MR Coronary Vessel Wall Imaging with Intravascular Ultrasonography.

Suzanne C. Gerretsen¹, M. Eline Kooi¹, Rene M. Botnar², Johannes Waltenberger³, Rob J. van der Geest⁴, J. Dijkstra⁴, J. H. Reiber⁴, Tim Leiner¹

¹Radiology, Maastricht University Medical Center, Maastricht, Netherlands; ²Dept. of Experimental MRI, King's College London, London, UK; ³Cardiology, Maastricht University Medical Center, Maastricht, Netherlands; ⁴LKEB, Radiology, Leiden University Medical Center, Leiden, Netherlands

In this study, MR of the coronary vessel wall (MR-CVW) was compared to the current in-vivo standard of reference for coronary vessel wall imaging: intravascular ultrasound (IVUS). Fourteen patients with chest pain underwent both MR-CVW and IVUS. On both IVUS and MR-CVW, areas of focal wall thickening in the RCA were identified and wall thickness was measured. The current study confirmed the ability of MR-CVW to detect areas of positive remodeling as seen with IVUS. There is a good agreement between IVUS and MRI with regard to location and extent of wall thickening. However, MR-CVW overestimated wall thickness approximately 3-fold.

                  1897.     Coronary Vessel Wall Imaging Using Reduced Field of View Double Inversion Recovery Fast Spin Echo

Hao Shen¹, Guang Cao², Qian Zhao³, Liuquan Cheng³, Chun Yuan⁴

¹Applied Science Laboratory,  GE Healthcare China, Beijing, China; ²Applied Science Laboratory,  GE Healthcare China, Hongkong, China; ³Department of Radiology , Chinese PLA General Hospital, Beijing, China; ⁴Department of Radiology, University of Washington, Vascular Imaging Laboratory, Seattle, WA, USA

Black blood imaging of coronary artery is requested to identify and characterize coronary artery plaque. In this work, breath-hold reduced field of view double inversion recovery fast spin echo sequence was evaluated for coronary artery vessel wall imaging.

                  1898.     Navigator-Gated Whole Heart Coronary MRI with 3D Isotropic Double Echo TrueFISP UTE

Sonia Nielles-Vallespin¹, Peter Speier¹, Peter Weale², Saurabh Shah², Edgar Mueller¹

¹Cardiovascular MR, Siemens AG Healthcare Sector, Erlangen, Germany; ²Cardiovascular MR, Siemens AG Healthcare Sector, Chicago, USA

A free-breathing navigator-gated isotropic 3D radial double echo UTE TrueFISP sequence has been implemented and used to acquire isotropic whole heart coronary images of healthy volunteers with a total scan time of about 13 min. This method provides state-of-the-art TrueFISP whole heart coronary images plus UTE images at almost no extra cost, only slightly longer TR, opening up the possibility to obtain a new contrast for a range of cardiovascular MR applications, such as detection of calcification in atherosclerotic plaque, depiction of fibrosis in the heart or visualization of iron labeled cells.

                  1899.     Analysis of Endocardial Border Sharpness of Accelerated 2D CINE SSFP:  Implications for Left Ventricular Function Assessment

Fabian Hezel¹, Marcus Katoh², Harald Kühl³, Helena Grawe³, Jane F. Utting¹, Thoralf Niendorf^1,4

¹Division of Experimental MR Imaging, Department of Diagnostic Radiology, University Hospital, RWTH Aachen, Germany; ²Department of Diagnostic and Interventional Radiology, University Hospital of Saarland, Homburg/Saar, Germany; ³Medical Clinic I, University Hospital, RWTH Aachen, Germany; ⁴Faculty of Mathematics, Computerscience and Natural Science, RWTH Aachen University, Aachen, Germany

Accelerated 2D CINE SSFP affords scan time reduction in LV function assessment though image blurring remains a concern. A method for endocardial border sharpness (EBS) analysis is introduced and applied to conventional, SENSE and k-t BLAST accelerated 2D CINE SSFP. A fairly rapid EBS degeneration was observed for k-t accelerations of R≥8. Consequently, the imaging speed advantage of k-t BLAST over conventional 2D CINE SSFP should be balanced against EBS deterioration. An acceleration of R<8 is advised for LV function assessment, which still provides sufficient acceleration to accomplish 3-4 slices per breath-hold without adverse effects on image quality.

                  1900.     Rapid and Accurate Quantification of Left Ventricular Ejection Fraction Using an Automated Segmentation Algorithm – a Clinical Validation Study

Noel Christopher Codella¹, Matthew D. Cham¹, Richard Wong^1,2, Christopher W. Chu³, Keigo Kawaji^1,2, Kirsten Healey³, Martin R. Prince¹, Yi Wang^1,2, Jonathan W. Weinsaft^1,3

¹Radiology, Weill Cornell Medical College, New York, USA; ²Biomedical Engineering, Cornell University, Ithaca, NY, USA; ³Medicine/Division of Cardiology, Weill Cornell Medical College, New York, USA

Cardiac magnetic resonance (CMR) is an imaging standard for quantification of LV ejection fraction (EF) and volume. CMR typically relies on manual tracing (MT), which can be time consuming and operator-dependent. Automated segmentation holds potential for rapid LV quantification. In this study, we evaluated LV-METRIC performance versus MT among a broad unselected patient population; compared processing time by LV-METRIC to MT, and compared LV-METRIC and MT to an independent standard of LV flow quantification. LV-METRIC successfully yielded EF within 2 points of MT, reduced the processing time by fourteen folds, and agreed with an independent standard.

                  1901.     The KLT Filter as a Method of "Smart Averaging" to Improve SNR in Real-Time Cine MRI

Yu Ding¹, Yiu-cho Chung², Orlando P. Simonetti¹

¹The Ohio State University, Columbus, OH, USA; ²Siemens Medical Solutions USA, Inc., Columbus, OH, USA

We propose here a combination of the Karhunen-Loeve Transform filter and prolonged data acquisition to improve the SNR of dynamic cardiac MR images. The temporal redundancy of real-time cardiac MR images increases with the number of cardiac cycles included, which can improve the performance of the KLT filter. In vivo experimental study showed that it is a practical way to recover SNR.

                  1902.     Morphological Studies of the Murine Heart Based on Probabilistic and Statistical Atlases

Dimitrios Perperidis¹, Elizabeth Bucholz², G Allan Johnson², Christakis Constantinides¹

¹Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia, Aglantzia, Cyprus; ²Radiology, Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, USA

                  1903.     Unsupervised Fully Automated Inline Analysis of Global Left Ventricular Function in MR Imaging

Daniel Theisen¹, Torleif Sandner¹, Kerstin Bauner¹, Carmel Hayes², Maximilian F. Reiser¹, Bernd J. Wintersperger¹

¹Department of Radiology, University of Munich, Munich, Germany; ²MR Division, Siemens Health Care, Erlangen, Germany

The purpose of this study was to implement a fully automated segmentation algorithm for the evaluation of the left ventricle within cine data acquisition and to compare the evaluated parameters of global left ventricular function to manual analysis as standard of reference in patients and healthy volunteers. There was a good agreement between automatic and manual results for EF, EDV, ESV and myocardial mass. Volumetric results of the automated inline analysis showed high correlation with results of manual segmentation. Unsupervised fully automated segmentation and contouring during image reconstruction enables accurate and instantaneous evaluation of global left ventricular performance.

                  1904.     3.0 Tesla MRI Common Carotid Wall Shear Stress Quantification: Poiseuille Estimation Versus Non-Linear Fitting of Velocity Data.

Raphael Duivenvoorden¹, Eric de Groot, Ed van Bavel², Ramsi Amri, Erik Stroes, J. Lameris³, J. Kastelein, Aart J. Nederveen³

¹Vascular Medicine, Academic Medical Center, Amsterdam, Netherlands; ²Medical Physics, Academic Medical Center; ³Radiology, Academic Medical Center

Wall shear stress (WSS) can be calculated by using MRI flow measurements. Commonly WSS is estimated based on Poiseuille flow assuming a parabolic velocity profile. In arteries in vivo this assumption is not valid. We therefore developed a method that calculated the velocity gradient near the wall using a non-linear fit of the MRI velocity data. This results in a more accurate determination of both systolic and diastolic wall shear stresses.

                  1905.     Platform for Comprehensive Hemodynamic Analysis of 4D PC MRI Data

Elizabeth Janus Nett¹, Kevin M. Johnson¹, Benjamin R. Landgraf², Oliver Wieben^1,2

¹Medical Physics, University of Wisconsin, Madison, WI, USA; ²Radiology, University of Wisconsin, Madison, WI, USA

New approaches for rapid MR imaging have allowed for the in vivo acquisition of volumetric phase contrast images of cine velocity fields for the examination of vascular anatomy and function. It also allows for the derivation of additional hemodynamic parameters such as wall shear stress and pressure gradients. However, the visualization and analysis of thousands of images containing anatomical and functional data pose a significant challenge for clinical work up. We developed and validated a software platform that streamlines hemodynamic measurements from PC VIPR acquisitions, including analysis plug-ins for flow measurements with automatic alignment with respect to vessel orientation and and tools for the derivation of wall shear stress and pressure gradients. Such a platform will be important for the clinical adaptation of 4D PC MRI.

                  1906.     A Nonparametric Method for Intensity Non-Uniformity Correction in Carotid MR Images

Wenbo Liu¹, Guangzhi Wang¹, Hui Ding¹

¹Biomedical Engineering, Tsinghua University, Beijing, China

In risk evaluation of carotid atherosclerotic disease, non-uniformity may occur because of the inhomogeneous sensitivity of a custom surface coil. We propose an approach which uses a nonparametric method based on entropy minimization and an optimization method called pattern search. With the experiment of 108 slices of four kinds of sequences, the results show that this approach has a high calculation efficiency (reduction factor=4, image size=512*512, one slice progressing time is about 45 seconds), and is prior knowledge independent. According to the results, this method can be widely used in the correction of the non-uniformity in MR images.

                  1907.     Time-Of-Arrival Mapping for 3D Time-Resolved Contrast-Enhanced MRA

Stephen J. Riederer¹, Clifton R. Haider¹, Eric A. Borisch¹

¹Mayo Clinic, Rochester, MN, USA

A method is described for forming an image of the time-of-arrival (TOA) of intravenously administered contrast material as determined from time-resolved 3D contrast-enhanced MR angiography. Colorization of TOA values may aid interpretation and allow easy distinction between arteries and veins. The quality of the results depends on the temporal fidelity of the MR acquisition method. TOA mapping is demonstrated using in vivo studies of peripheral MRA.

                  1908.     Localized Measurement of Atherosclerotic Plaque Inflammatory Burden with Dynamic Contrast-Enhanced MRI

Huijun Chen¹, Jianming Cai², Xihai Zhao¹, Thomas S. Hatsukami³, Chun Yuan¹, William S. Kerwin¹

¹Department of Radiology, University of Washington, Seattle, WA, USA; ²Department of Radiology, PLA General Hospital, Beijing, China; ³Department of Surgery, University of Washington, Seattle, WA, USA

Inflammation is important in both the pathogenesis and outcome of atherosclerosis. Recently, dynamic contrast-enhanced (DCE-MRI) has been shown to be sensitive to inflammatory content within plaque. In this study, we sought to demonstrate the ability of DCE-MRI to provide localized measurements by comparing the transfer constant (Ktrans) of contrast agent uptake across plaque regions with different composition. The result shows that different plaque components are associated with different values of Ktrans. Loose matrix has the highest measured Ktrans due to its loosely organized fibrous tissue with high water content and permeability. In contrast, necrotic core, hemorrhage, and calcification are poorly perfused regions with substantially lowered values of Ktrans. These results suggest that DCE-MRI is able to detect differences in Ktrans within plaque regions with different composition, reflecting the varying vascularities and permeabilities of each region.

                  1909.     P31 NMR Demonstrates Dysfunction Through Mitochondrial Uncoupling in Skeletal Muscle After Burn Injury

Dionyssios Mintzopoulos¹, Meenu Kesawarni^1,2, Laurence G. Rahme³, Ronald G. Tompkins⁴, A Aria Tzika¹

¹NMR Surgical Laboratory, MGH & Shriners Hospitals, Harvard Medical School, Boston, MA, USA; ²Molecular Surgery Laboratory, MGH & Shriners Hospitals, Harvard Medical School, Boston, MA, USA; ³Molecular Surgical Laboratory, MGH & Shriners Hospitals, Harvard Medical School, Boston, MA, USA; ⁴Surgery, MGH & Shriners Hospitals, Harvard Medical School, Boston, MA, USA

We employed in vivo P31 NMR on intact uncoupling protein 3 (UCP3) knock-out and wild-type (control) mice, following 30% total burned surface area burn to assess the ATP synthesis rate in skeletal muscle. Our results revealed that the rate of ATP synthesis in UCP3 mice is significantly reduced as compared to controls. These findings implicate mitochondrial uncoupling in skeletal muscle following burn injury.

                  1910.     Influence of Foot Orientation on the Appearance of ¹H Muscle Spectra Obtained from Soleus and Vastus Lateralis

Malgorzata Marjanska¹, Lisa Chow², Gregor Adriany¹, Elizabeth R. Seaquist², Michael Garwood^1
1Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, MN, USA; ²Division of Endocrinology, Diabetes, and Metabolism, University of Minnesota, Minneapolis, MN, USA

In vivo ¹H spectroscopy in skeletal muscle has been more frequently performed in the lower leg than the thigh. It has been shown at 3 T that ankle orientation alters bulk susceptibility and residual dipolar couplings of protons in the calf skeletal muscle. With in vivo ¹H MRS, changes in the residual dipolar couplings have been observed on creatine and TMA with ankle orientation. Additionally, changes in ankle orientation also affected the separation of intramyocellular and extramyocellular lipids. In this project, we investigate the influence of ankle orientation on ¹H spectra from the thigh, specifically the vastus lateralis muscle.

                  1911.     ³¹CSI and MRS at 7T Detect an Alkaline PH Compartment in Resting Human Soleus Muscle

Hermien E. Kan¹, Dennis W.J. Klomp², Andrew G. Webb¹, Peter R. Luijten², Jeroen A.L. Jeneson³

¹Radiology, Leiden University Medical Center, Leiden, Netherlands; ²High field MR laboratory, RNN, University Medical Center Utrecht, Utrecht, Netherlands; ³3Biomedical NMR Laboratory, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands

Non-invasive fiber-type profiling of human skeletal muscles has been a long-time objective in musculoskeletal MR research. Up till now, most MR studies focused on contracting muscles to obtain a measure for fiber type. In the present study we show, for the first in resting human skeletal muscle, the existence of different pH compartments in the soleus muscle. We hypothesize that the second Pi resonance at 5.2 ppm originates from the mitochondrial matrix in type I myofibers, thereby providing a non-invasive measure for the in vivo free Pi concentration in mitochondria.

                  1912.     Slow Decay of Acetyl-Carnitine in Skeletal Muscle After Exercise

Jimin Ren¹, Ivan Dimitrov², Dean Sherry¹, Craig Malloy¹

¹University of Texas Southwestern Medical Center, Dallas, TX, USA; ²Philips Medical Systems, Cleveland, OH, USA

Rapid interconversion of acetyl-CoA with acetyl-carnitine buffers acetyl-CoA when the rate of generation of acetyl-CoA exceeds the rate of oxidation. Exercise has been shown to increase acetyl-carnitine little is known about the kinetics of recovery. Healthy subjects were studied by single-voxel spectra acquired from soleus muscle using a 7T scanner. Standard calf flexion / extension exercise was performed outside the magnet. The resonance areas of carnitine, creatine and taurine did not change during recovery. Acetyl-carnitine decayed slowly with a rate constant of 19.3 +/- 2.4 min. The acetyl-carnitine/carnitine ratio remains high for a prolonged period after exercise.

                  1913.     Differences in Skeletal Muscle Lipid Metabolism in Upper and Lower Extremities by Localized Correlated Spectroscopy

Steven L. Lindauer¹, John Austin Vargo¹, Steven Coon², Raymond R. Raylman¹, M. Albert Thomas³, Richard G. Spencer⁴, Stephen E. Alway⁵, S. Sendhil Velan¹

¹Center for Advanced Imaging and Department of Radiology, West Virginia University, Morgantown, WV, USA; ²Section of Digestive Diseases, Department of Medicine, West Virginia University, Morgantown, WV, USA; ³Radiology, UCLA, Los Angeles, CA, USA; ⁴Magnetic Resonance Imaging and Spectroscopy Section, NIA, National Institutes of Health, Baltimore, MD, USA; ⁵Department of Exercise Physiology, West Virginia University, Morgantown, WV, USA

We have investigated the skeletal muscle lipid metabolism in upper and lower extremities. Our preliminary measurements of intramyocellular lipids in upper and lower extremities indicate differences in their accumulation which might be due to the different physical activity pattern for the two extremities. The forearms might be less prone to the development of insulin resistance due to greater involvement in daily physical activities.

                  1914.     31P NMR Demonstrates Reduced ATP Synthesis Rate and Concomitant Downregulation of PGC-1β Mitochondrial Gene Expression in Skeletal Muscle After Burn Injury

Dionyssios Mintzopoulos^1,2, Michael N. Mindrinos³, Laurence G. Rahme⁴, Ronald G. Tompkins⁵, A Aria Tzika^1,6

¹NMR Surgical Laboratory, MGH & Shriners Hospitals, Harvard Medical School, Boston, MA, USA; ²Radiology, Athinoula Martinos Center for Biomedical Imaging, Boston, MA, USA; ³Biochemistry, Stanford University School of Medicine, Palo Alto, CA, USA; ⁴Molecular Surgical Laboratory, MGH & Shriners Hospitals, Harvard Medical School, Boston, MA, USA; ⁵Surgery, MGH & Shriners Hospitals, Harvard Medical School, Boston, MA, USA; ⁶Radiology, Athinoula A. Martinos Center of Biomedical Imaging, Boston, MA, USA

We employed in vivo P31 NMR on intact mice, in a 30% total burned surface area burn model. We examined ATP synthesis and the gene expression of the peroxisome proliferator-activated receptor coactivator 1 (PPARg coactivator-1 or PGC-1), involved in regulation of metabolism. Our in vivo NMR results that showed significantly reduced rate of ATP synthesis were cross-validated with gene expression analysis, showing downregulation of the PGC-1b gene expression. We demonstrated that there is high correlation between ATP synthesis rate and PGC-1b  gene expression. These findings implicate mitochondrial dysfunction in distal skeletal muscle following burn injury.

                  1915.     T1 and T2 Relaxation Time Measurements of Metabolites in Human Calf Muscle at 7 Tesla

Jimin Ren^1,2, Ivan Dimitrov^1,3, A. Dean Sherry^1,4, Craig R. Malloy^1,5

¹Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA; ²Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA; ³Philips Medical Systems; ⁴Department of Chemistry, University of Texas at Dallas, Richardson, TX, USA; ⁵VA North Texas Health Care System

Proton MRS is becoming increasingly important as a diagnostic tool in metabolic diseases owing to its non-invasiveness and specificity. High-field MRS in particular offers the advantage of intrinsic high spectral resolution and sensitivity. For quantitative measures of metabolites in vivo, accurate T1 and T2 values are important not only for optimizing acquisition parameters but also to provide information about the molecular environment of various tissue metabolites. T1 and T2 values were measured for several common aqueous metabolites in calf skeletal muscle (creatine(Cr), carnitine(Ctn), taurine(Tau) and water) at 7 Tesla using a STEAM-based sequence.

                  1916.     Progression of Fat Infiltration in Calf, Thigh and Pelvic Muscles in Duchenne Muscular Dystrophy: Quantification by MRI Over an 18 Month Period

Kieren Grant Hollingsworth¹, Penelope Garrood², Benjamin Segun Aribisala¹, Daniel Birchall³, Michelle Eagle², Kate Bushby², Volker Straub²

¹Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle, Tyne and Wear, UK; ²Institute of Human Genetics, Newcastle University, Newcastle, Tyne and Wear, UK; ³Regional Neurosciences Centre, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle, Tyne and Wear, UK

Knowledge of the progression of fatty infiltration is important in designing therapy trials for Duchenne Muscular Dystrophy. 11 ambulant boys with DMD (age at recruitment 6.6-9.9 years) were studied at 0, 9 and 18 months. T1-weighted imaging was performed of the muscles of the calf, thigh and pelvis, and T2 measurements were made of the thigh muscles, to track the progress of fatty infiltration. T1w imaging was related to the bone marrow intensity and showed greater progression in the pelvis and thigh muscles than the calf (except gracilis). T2 measurement confirmed progression in all muscles of the thigh.

                  1917.     Quantitative MRI Analysis of Two Icing Techniques in Skeletal Muscle Injury in a Rat Hind Limb Model

Thomas Neuberger¹, Andrew Webb², Eric Fontaine³, Nicole McBrier³

¹Huck Institute, Penn State University, USA; ²Radiology, Leiden University Medical Center, Leiden, Netherlands; ³Kinesiology, Penn State University

Cooling of acute contusion injuries can help reduce the extent and duration of injury. In this study the effect of two different cooling schemes was probed using quantitative volumetric and relaxation time MRI measurements. A continuous cooling approach in which cooling was applied for 6 hours was compared to a cooling scheme which consisted of 30 minute cooling periods and 1 hour non-cooling periods for a total of 6 hours. The results suggest that intermittent cooling for 30 minutes may be just as effective as continuous cooling.

                  1918.     Compartmental Relaxation Measurements in a Graded Muscle Edema Model

Jack Thomas Skinner^1,2, Mark D. Does^1,2

¹Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; ²Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA

MRI provides an excellent way of visualizing muscle inflammation; however, there are few techniques that serve to quantitatively assess edematous muscle. To investigate changes in relaxation times with injury, a graded edema model in rats was produced by subcutaneous injections of a l-carrageenan solution at varied concentrations. Saturation recovery prepared multiple spin-echo (SR-ME) measurements at 9.4T revealed both multiexponential T₁ and T₂ in edematous muscle. A decrease in injection concentration resulted in a decrease in the volume fraction of the long-lived component and a decrease in T₁. These results indicate that relaxation times can be markers of muscle injury severity.

                  1919.     Perfusion Imaging of Free Flaps with Contrast Harmonic Ultrasound Imaging, Laser-Induced Indocyanine Green Fluorescence Angiography and Magnetic Resonance Imaging

Ernst M. Jung¹, Lukas Prantl², Andreas G. Schreyer¹, Niels Zorger¹, Stefan Feuerbach¹, Claudia Fellner¹

¹Institute of Radiology, University of Regensburg, Regensburg, Germany; ²Department of Trauma and Plastic Surgery, University of Regensburg, Regensburg, Germany

To evaluate postoperative tissue perfusion of microvascular flaps of the lower leg, 10 patients underwent contrast enhanced harmonic ultrasound imaging (CHI), laser-induced indocyanine green (ICG) fluorescence angiography and perfusion weighted (PW) MRI. For MRI global time intensity curves and color-coded relative blood volume maps were evaluated qualitatively. For CHI and ICG time intensity curves in selected regions of interest were analyzed. Correlation between CHI, MRI and ICG was 0.69 – 0.83 for the distal parts, 0.74 – 0.87 for the center of the flaps. Therefore, CHI and PW MRI might be a promising tool for postoperative monitoring in patients with free flaps.

                  1920.     Perfusion Measurements During Reactive Hyperemia in Human Soleus Muscle

Markus Klarhöfer¹, Claudia Lenz¹, Tanja Haas¹, Klaus Scheffler¹, Rolf Pohmann²

¹Division of Radiological Physics, University of Basel Hospital, Basel, Switzerland; ²MPI for Biological Cybernetics, Tübingen, Germany

The non-invasive quantification of perfusion of human skeletal muscle using arterial spin labeling methods is complicated by low tissue perfusion and low sensitivity of the applied acquisition techniques. The aim of this study was to evaluate the feasibility of a single-voxel FAIR technique for the quantification of perfusion in the soleus muscle of healthy volunteers during an ischemia/reactive hyperemia paradigm. Averaged over three subjects, a mean resting state perfusion of 24 +/- 7 ml/100g/min and a mean maximum perfusion during hyperemia of 139 +/- 32 ml/100g/min were found.

                  1921.     Line Scan Diffusion Spectrum of the Denervated Skeletal Muscle for Early Diagnosis of Peripheral Nerve  Injuries: An Experimental Study

Eiko Yamabe¹, Toshiyasu Nakamura², Yukihiko Obara³, Koji Abe⁴

¹Department of Orthopaedic Surgery, Hiratsuka City Hospital, Hiratsuka City, Kanagawa, Japan; ²Department of Orthopaedic Surgery, School of Medicine, Keio University, Tokyo, Japan; ³Department of Orthopaedic Surgery, Saitama Social Insurance Hospital, Saitama, Japan; ⁴Department of Orthopaedic Surgery, Scool of Medicine, Keio University, Tokyo, Japan

The ADC of the skeletal muscle increased quickly after the damage of the dominant peripheral nerve and was detectable one day after the damage. Diffusion MRI can be a useful tool for early detection of peripheral nerve injury insstead of T2-weighted MRI.

                  1922.     Evaluation of Skeletal Muscles After Strenuous Exercise with Magnetic Resonance Imaging and Ultrasonography

Osamu YANAGISAWA¹, Toshiyuki KURIHARA¹, Koji OKUMURA¹, Toru FUKUBAYASHI¹

¹Waseda University, Tokorozawa, Saitama, Japan

Problem: Exercise-induced muscle damage has not been sufficiently evaluated.

                  1923.     Independent Effect of Extravascular BOLD Effects on Muscle Relaxation Parameters

Otto Alexander Sanchez¹, Elizabeth Anne Copenhaver¹, Marti Ann Chance², Bruce Murray Damon^1,3

¹Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, USA; ²Radiology and Raidological Sciences, Vanderbilt University, Nashville, TN, USA; ³Biomedical Engineering, Vanderbilt University, Nashville, TN, USA

The extravascular BOLD effect depends on blood oxygenation, blood volume, the diffusion coefficient of water and blood vessel orientation with respect to B0. To study the independent effects of these factors water diffusion properties, R2 and R2* were measured in the lateral gastrocnemius muscle of eight healthy subjects. The subjects were studied with the leg fully extended and partially flexed with and without proximal arterial occlusion. The absence of a significant Occlusion × Leg Position interaction indicates that the extravascular BOLD effect does not contribute to signal intensity changes in T2 and T2*-weighted images of exercising muscle at 3T.

                  1924.     Similarity Between Deoxyhemoglobin Concentration and R2’ Time Course During Isometric Dorsiflexion

Christopher Paul Elder¹, Marti Ann Chance¹, Ryan N. Cook², Bruce M. Damon^1,2

¹Radiology and Radiological Sciences and Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; ²Biomedical Engineering, Vanderbilt University, Nashville, TN, USA

There is a need to develop MR techniques to measure oxygen extraction in skeletal muscle. The purpose of this study was to determine if R2’ and deoxyhemoglobin concentration ([Hb]) exhibit similar time course during submaximal isometric contraction. Six subjects performed a 120s submaximal isometric dorsiflexion while [Hb], R2*, R2 were measured. The R2’ and [Hb] time courses showed excellent similarity in 3 subjects and dissimilarity in another 3. Similarity exists in subjects with free perfusion while dissimilarity exists in subjects with limited perfusion during contraction. <

                  1925.     Accuracy and Precision of MR Blood Oximetry Based on the Long Paramagnetic Cylinder Approximation of Large Vessels

Michael C. Langham¹, Jeremy Magland¹, Charles L. Epstein², Thomas F. Floyd³, Felix W. Wehrli¹

¹Radiology, University of Pennsylvania, Philadelphia, PA, USA; ²Mathematics, University of Pennsylvania, Philadelphia, PA, USA; ³Anesthesiology and Critical Care, Universityy of Pennsylvanis, Philadelphia, PA, USA

The accuracy and precision of MR susceptometry-based oximetry was investigated theoretically on the basis of an analytical expression for the arbitrarily oriented cylinder, as well as experimentally in phantoms and in vivo in the femoral artery and vein at 3T field strength. Hemoglobin saturation was measured at successive vessel segments, differing in geometry but constant blood oxygen saturation levels, as a means to evaluate measurement consistency. Reproducibility of in vivo HbO₂ quantification was on the order of 5% in the femoral vessels and the data indicate that non-circularity, although corrigible, can be ignored even at 30^o with tilt correction alone.

                  1926.     SNR Requirements for Accurate Estimation of Magnitude and Kinetic Properties of Post-Contraction Signal Transients

Elizabeth A. Copenhaver¹, Otto A. Sanchez, Bruce M. Damon

¹Vanderbilt University, Nashville, TN, USA

Following brief isometric contractions, gradient echo signal intensities acquired at TE=6 ms reflect changes in blood volume. This technique can be used to evaluate microvascular function, but the minimum SNR required for accurate amplitude and kinetic parameter estimation is unknown. Using Monte Carlo simulations, it was found that an SNR of 60 allows accurate estimation of amplitude and kinetic parameters for ROI sizes greater than 50 voxels and post-contraction signal intensity changes greater than 0.12% of pre-contraction baseline.

                  1927.     Diffusion Tensor Imaging of the Human Calf – Distinct Changes in Fractional Anisotropy and Mean Diffusion Due to Muscle Shortening and Stretching

Nina F. Schwenzer^1,2, Günter Steidle², Petros Martirosian², Christina Schraml¹, Fabian Springer¹, Claus D. Claussen¹, Fritz Schick²

¹Department of Diagnostic and Interventional Radiology, University Hospital of Tübingen, Tübingen, BW, Germany; ²Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, University Hospital of Tübingen, Tübingen, BW, Germany

Diffusion tensor imaging (DTI) is able to display diffusional anisotropy of tissue. It is known that the muscle has a highly ordered microarchitecture. It seems plausible that water diffusivity within the muscle will change with length since the cross sectional area of the muscle increases with shortening. This could have an influence on diffusivity and fractional anisotropy (FA). Our results showed that the FA significantly decreased and the mean diffusivity increased with muscle shortening. Regarding the eigenvalues of the diffusion tensor, l2 and l3 showed significant changes in relation to muscle length while no change in l1 could be found.

                  1928.     Mapping Cross-Sectional Skeletal Muscle Asymmetry Via High Angular Resolution Diffusion Imaging

Dimitrios C. Karampinos^1,2, Kevin F. King³, Danchin Chen¹, Bradley P. Sutton^2,4, John G. Georgiadis^1,2

¹Mechanical Science and Engineering Department, University of Illinois at Urbana-Champaign, Urbana, IL, USA; ²Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL, USA; ³GE Healthcare, Waukesha, WI, USA; ⁴Bioengineering Department, University of Illinois at Urbana-Champaign, Urbana, IL, USA

Although it has been reported that the secondary eigenvalue is consistently different than the tertiary eigenvalue in diffusion tensor imaging of the skeletal muscle, the etiology of the asymmetry of skeletal muscle transverse diffusivity is under debate. In the present work, we apply high angular resolution diffusion imaging (HARDI) to study the transverse diffusion asymmetry. A circular spectrum decomposition of the transverse diffusivity is proposed to quantify this asymmetry with HARDI measurements and to test the adequacy of the diffusion tensor model to represent the underlying diffusion process in the range of b-values used in in-vivo muscle DTI experiments.

                  1929.     Muscle Fiber Tracking and Segmentation in the Human Forearm

Martijn Froeling¹, Jos Oudeman², Sandra van den Berg², Anna Vilanova³, Klaas Nicolay¹, Mario Maas², Gustav Strijkers¹, Aart Nederveen², Maarten Drost⁴

¹Biomedical NMR, Department of Biomedical Engeneering, Eindhoven University of Technology, Eindhoven, Netherlands; ²Department of Radiology, Academic Medical Center, Amsterdam, Netherlands; ³Biomedical Image Analysis, Department of Biomedical Engeneering, Eindhoven University of Technology, Eindhoven, Netherlands; ⁴Department of Human Movement Sciences, Maastricht University, Maastricht, Netherlands

In this study we used diffusion tensor imaging in combination with fiber tracking algorithms to characterize human forearm muscle architecture. We segmented the muscles on the basis of fiber tracking and demonstrated the feasibility of characterization and visualization of human forearm muscle architecture in great detail.

                  1930.     Diffusion Tensor Magnetic Resonance Imaging (DTI) of Abnormalities in the Thigh Muscles of Polymyositis Patients

Jane H. Park^1,2, Brittany C. Lee^1,2, Jing Qi^2,3

¹Molecular Physiology, Vanderbilt University Medical School, Nashville, TN, USA; ²Radiology, Vanderbilt University Medical School, Nashville, TN, USA; ³Radiology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China

Polymyositis (PM) is an inflammatory muscle disease characterized by severe proximal weakness, fatigue, and high serum levels of muscle enzymes. MRI has demonstrated heterogeneous composition of PM thigh muscles ranging from normal to inflamed and/or fat-infiltrated. With diffusion tensor imaging (DTI), ADC values showed increased water motion in inflamed muscles and decreased motion with fat infiltration. Eigenvalues (λ₁, λ₂, λ₃) confirmed anisotropy in all PM muscles. Tractography demonstrated shorter and less uniform fibers in affected muscles. Unaffected patient muscles were not significantly different from control subjects. To our knowledge, this is the first DTI examination of inflammatory muscle diseases.

                  1931.     Dynamic DTI During Muscle Contraction by Electrical Stimulation.

Yasuharu WATANABE¹, Keisaku KIMURA², Masahiro UMEDA¹, Toshihiro HIGUCHI³, Chuzo TANAKA³

¹Medical Informatics, Meiji University of Integrative Medicine, Kyoto, Japan; ²Heath Promoting and Preventive Medicine, Meiji University of Integrative Medicine, Kyoto, Japan; ³Neurosurgery, Meiji University of Integrative Medicine, Kyoto, Japan

Purpose of this study is to estimate speeds and directions of water molecules during muscle contraction. Dynamic DTI was performed in order to estimate speeds and directions of water molecules during electrically stimulated contraction. ă1 and ă2 values showed significant increase during the muscle contraction. These results indicate that rapid water movement occurred in the direction other than muscular long axis at least during the muscle contraction. This study suggests that the muscle contraction induced the movements of the rapid water molecules to muscular short axis direction as well as long axis.

                  1932.     Improved Estimation of Muscle Water Diffusion Properties Using Dixon Imaging

Bruce M. Damon¹, Jane H. Park, J. Herman Kan¹

¹Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, USA

Diffusion imaging may reflect muscle damage in a manner distinct from T2, but can be confounded by fat infiltration. In this work it is shown that by combining asymmetric spin-echo Dixon imaging with diffusion measurements, improved estimates of the water diffusion properties of skeletal muscle can be obtained.

                  1933.     MRI Assessment of Passive Muscular Mechanics in Vivo Using Intensity Based Nonrigid B-Spline Registration: Effects of Epimuscular Myofascial Force Transmission

Alper Yaman¹, Maria J. Ledesma-Carbayo², Guus C. Baan³, Peter A. Huijing³, Can A. Yucesoy¹, Cengizhan Ozturk¹

¹Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey; ²Departamento de Ingeniería Electrónica, Universidad Politécnica de Madrid, Madrid, Spain; ³Research Instituut. Move, Faculteit Bewegingswetenschappen, Vrije Universiteit, Amsterdam, Netherlands

In addition to myotendinous pathways, important pathways for transmission of muscle force are comprised by connective tissue structures providing mechanical linkage between muscles and neighboring muscular and nonmuscular tissues. Experimentally and using finite element modeling, such epimuscular myofascial force transmission (EMFT) has been shown to affect muscular mechanics substantially in the rat, leading to proximo-distal force differences and major sarcomere length heterogeneity. The purpose of this work is showing effects of EMFT using MRI in human in vivo by calculating strain fields via intensity based nonrigid B-spline semilocal registration.

                  1934.     Accuracy and Precision Analysis of a Semi-Automated Spatial Tag Position Detection Method

Erin Kristine Englund¹, Bruce M. Damon²

¹Biomedical Engineering, Vanderbilt University, Nashville, TN, USA; ²Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, USA

Spatial tagging methods such as SPAMM provide information about tissue displacement during movement, however the analysis of tag position is time consuming and subjective. Using the proposed semi-automated method, it was possible to detect tag position in any image plane for spatial line tags. This decreased analysis time and subjectivity of tag detection. The method described is accurate to <0.03% for static images and can be applied to dynamic images as well.

                  1935.     Advanced Exercise Ergometer Setup for in Vivo MRS Studies of Skeletal Muscle Metabolism

Susanne Heinzer-Schweizer¹, Flurin Item^2,3, Anke Henning¹, Marco Toigo^2,3, Peter Boesiger¹

¹Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland; ²Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland; ³Exercise Physiology, Institute for Human Movement Sciences, ETH Zurich, Zurich, Switzerland

Magnetic resonance spectroscopy (MRS) is frequently used to assess dynamic metabolic changes in skeletal muscle. To study metabolism during exercise in an MR scanner, ergometers have to be designed that are compatible with the constraints imposed by the scanner. We present an improved MRS ergometer setup for the measurement of muscular metabolism during isometric contractions of the plantarflexor muscles. Key features of the setup are a pedal with an integrated strain gauge, flexible adjustment of ankle joint angle, and real-time visual feedback for subjects on momentary contraction. Using this setup, we were able to determine metabolic parameters under standardized conditions.

                  1936.     Quantitative Assessment of Trabecular Bone Structure in the Presence of Bone Marrow Edema-Like Lesions (BMEL): IDEAL Versus FIESTA-C

Radu Ioan Bolbos¹, Daniel Kuo¹, Ann Shimakawa², Huanzhou Yu², Michael Ries³, Sharmila Majumdar^1,3, Xiaojuan Li¹

¹Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA; ²Applied Science Laboratory, GE Healthcare – ASL West, Menlo Park, CA, USA; ³Department of Orthopaedic Surgery, University of California San Francisco, San Francisco, CA, USA

The trabecular bone structure, commonly reported using Fiesta-c imaging cannot be evaluated reliably within the region with Bone Marrow Edema-like Lesions (BMEL) due to presence of water which is also dark (as the bone) in these regions. The aim of this study was to employ an investigational version of IDEAL based on SPGR sequence (which provides robust fat-water separation) to quantitatively assess the trabecular structure within the BMEL region, and to validate the measurements using high-resolution peripheral quantitative CT (HR-pQCT). Within BMEL, Fiesta-c generated higher bone structure quantification compared to IDEAL, due to potential overestimations of bone.

                  1937.     Quantitative Measurement of Bone Marrow Composition and Bone Structure Using Simultaneous Acquisition of Fat Fraction and T2* with Multiple Gradient Echo Images

Eito Kozawa¹, Tomoyuki Okuaki², Waka Saito³, Kaiji Inoue⁴, Yasuo Sakurai⁵, Fumiko Kimura⁶

¹Radiology, Saitama Medical University, Hidaka, Saitama, Japan; ²Philips Medical System, Japan; ³Saitama Medical University , Japan; ⁴Radiology, Japan; ⁵Central Radiology, Saitama Medical University, Japan; ⁶Radiology, Saitama Medical University, Saitama, Japan

We illustrate its use for measuring lumbar spine of fat fraction and T2* in normal adults and hematological disease patients with multiple gradient echo images (MGE). Fat fractions of MGE vs. MR spectroscopy (MRS), and T2* vs. aging change were analyzed by linear regression. Fat fraction values of MGE and MRS show very good agreement. T2* values vs. aging change showed negative linear correlation. In conclusion, MR determination of those parameters could be used to assess and diagnose a deficiency in marrow composition and bone structure using fat fraction and T2*.

                  1938.     Simultaneous Estimation of T2, T2-Dagger and Lipid Content in Bone with a Novel Iterative Algorithm

Christian Graff¹, Kenneth L. Weiss², Eric W. Clarkson³, Maria I. Altbach³

¹Program in Applied Mathematics, University of Arizona, Tucson, AZ, USA; ²Department of Radiology, University of Cincinnati, Cincinnati, OH, USA; ³Department of Radiology, University of Arizona, Tucson, AZ, USA

Bone marrow is a challenging region of the body for MR imaging due to the presence of two chemical species, both fatty yellow bone marrow and red bone marrow, as well as micro-trabeculae which cause significant intra-voxel de-phasing (characterized by the time constant T2†). In this work we present a novel iterative algorithm which simultaneously provides estimates of T2† to evaluate the bone architecture, as well as an estimate of the relative lipid concentration and T2 of the water component for the characterization of lesions using data acquired with the GRASE technique.

                  1939.     Reproducibility of Trabeculae Bone Structural Parameters at Two Resolution Regimes

Michael J. Wald¹, Jeremy F. Magland¹, Yusuf Bhagat¹, Hee Kwon Song¹, Felix W. Wehrli¹

¹Laboratory for Structural NMR Imaging, University of Pennsylvania Medical Center, Philadelphia, PA, USA

The sensitivity to changes in trabecular bone microstructure is limited by SNR. Since TB aligns preferentially along the direction of loading (z-axis), a larger voxel width along that direction can be tolerated. Nevertheless, an increase in resolution along z-direction is likely to improve the accuracy of the structural analysis but is hampered by the achievable SNR. Here, the reproducibility of trabecular bone structural parameters is examined for two high resolution acquisitions to determine the potential for isotropic imaging using a 160μm voxel size at 3T. Potential sources of error are minimized and good reproducibility is achieved. The potential improvement in accuracy afforded by the isotropic voxel size comes with a slight reduction in reproducibility relative to the anisotropic acquisition.

                  1940.     Evaluation of Motion Corruption on Image Quality in Micro MRI of Trabecular Bone: Impact on Structural Parameters

Yusuf A. Bhagat¹, Michael J. Wald¹, Chamith S. Rajapakse¹, Hamid Saligheh Rad¹, Jeremy F. Magland¹, Mary B. Leonard², Felix W. Wehrli¹

¹Laboratory for Structural NMR Imaging, Radiology, University of Pennsylvania, Philadelphia, PA, USA; ²Nephrology, Children's Hospital of Philadelphia, Philadelphia, PA, USA

In this work, we aimed to evaluate the robustness of an image evaluation system for trabecular bone (TB) imaging by applying several translational motion trajectories to a relatively motion-free good quality TB image and compared the mean scores (from 4 raters) obtained from the image rating scheme to an objective image sharpness criterion chosen as the normalized gradient squared (NGS). Images demonstrating a poor NGS value (>1% reduction) relative to the original uncorrupted image, can demonstrate a change in the digital topological parameters from 8-24%, thereby conferring substantial weight to an image evaluation system for routinely grading in vivo scans.

                  1941.     Is Bone Marrow Diffusion Too Slow or Too Fast for Susceptibility-Based Methods to Assess Trabecular Bone Architecture?

Henry H. Ong¹, Alexander C. Wright¹, Suzanne L. Wehrli², Catherine E. Jones¹, Felix W. Wehrli¹

¹Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania School of Medicine, Phildelphia, PA, USA; ²NMR Core Facility, Children’s Hospital of Philadelphia, Philadelphia, PA, USA

Fatty acid triglycerides (FAT) are ubiquitous in nature and understanding their physico-chemical properties provides insight into their function. FAT diffusion in marrow is of interest as bone-marrow susceptibility effects are exploited to assess trabecular bone architecture in several approaches that make specific assumptions on the rate of FAT diffusion. To the best of our knowledge, FAT diffusion data have not been reported previously. Using pulsed-gradient spin-echo NMR, we report FAT ADC in intact yellow bone marrow (ADC~10^-8 cm²/s) to be three orders of magnitude slower than that of free water by means of a custom-built 50T/m z-gradient/RF coil set.

                  1942.     Relaxometric Characterization of Human Cortical Bone

Robert Adam Horch^1,2, Richard Darrell Dortch^1,2, Jeffrey S. Nyman³, Daniel Frank Gochberg^2,4, Mark. D. Does^1,2

¹Biomedical Engineering, Vanderbilt University, Nashville, TN, USA; ²Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; ³Orthopaedics & Rehabilitation, Vanderbilt University, Nashville, TN, USA; ⁴Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, USA

Human cortical bone contains an array of microanatomical water environments, such as restricted pore spaces, collagen networks, and hydroxyapatite mineral surface hydration zones. As such, in proton NMR measurements cortical bone exhibits a distribution of relaxation times, which are characterized herein by CPMG at 0.5, 4.7, 7, and 9.4 T to examine magnetic field dependencies. Hard and soft inversion-recovery CPMG measurements are also presented, which yield T₁-T₂ spectra indicative of magnetization transfer among cortical bone relaxation components. At the studied field strengths, cortical bone exhibits a range of T₂s from 100us to 500ms, with T1s spanning 20ms to 500ms.

                  1943.     Non-Gaussian Diffusion to Investigate Bone Marrow

Silvia De Santis¹, Silvia Capuani²

¹Physics Department Sapienza University Rome, Rome, Italy; ²CNR-INFM SOFT, Physics Department Sapienza University Rome, Rome, Italy

Parametric maps based on the mean anomalous exponent ã (Mã) and on its anisotropy (Aã) may offer complementary information compared to conventional DTI-maps. Our aim was to characterize the peculiar water diffusion behavior in calf bone-marrow by means of ã evaluation at different lipid-to-water ratios. Mã in 8 months bone marrow sample shows a strong deviation from Gaussian diffusion. This could be due to a more complex water compartmentalization in 8 months bone marrow sample compared to samples characterized by a lower water/fat ratio. Mã and Aã maps result less affected by susceptibility and chemical-shift artifacts than the conventional DTI-maps.

                  1944.     High Resolution Imaging of  Trabecular Bone Structure Using Wideband SSFP

Suchandrima Banerjee¹, Ajit Shankaranarayanan¹, Hsu-Lei Lee², Krishna S. Nayak², Sharmila Majumdar³, Eric T. Han¹

¹Applied Science Laboratory, GE Healthcare, Menlo Park, CA, USA; ²Magnetic Resonance Engineering Laboratory, Ming Hsieh Department of Electrical Engineering, University of  Southern California, Los Angeles, CA, USA; ³Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA

Balanced steady state free precession (SSFP) sequences are attractive because of their high SNR efficiency but are highly sensitive to off-resonance, experiencing signal nulls at intervals of 1/TR. When imaging trabecular bone micro-architecture with SSFP, the high-resolution acquisition necessitates long TR’s. A multiple phase-cycled SSFP (m-SSFP) approach with 100% scan time penalty has previously been employed to avoid such banding artifacts. In this work we investigate if a wideband SSFP (w-SSFP) scheme can be used instead of m-SSFP to reduce off-resonance effects in less scan time. Initial results suggest that w-SSFP has strong potential as a faster alternative to m-SSFP.

                  1945.     Spectrally-Selective IR Diffusion-Weighted Imaging with SSFP of Bone Marrow at 3T

Yousef Mazaheri¹, Jan Grimm², Ersin Bayram³, David M. Panicek², Jason A. Koutcher¹, Hedvig Hricak²

¹Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA; ²Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA; ³GE Healthcare, Wakesau, WI, USA

The purpose of this study was to determine the feasibility of diffusion-weighted imaging of bone marrow with a spectrally selective IR pulse SSFP sequence at 3T. The effectiveness of diffusion measurements with this technique was shown on phantoms and in vivo.

                  1946.     Measurements of Inter- And Intravoxel Dephasing of Trabecular Bone at 7T Field Strength Using a Chemical Shift-Selective Asymmetric Spin-Echo (Chase) Sequence

Roland Krug¹, Andrew J. Burghardt¹, Kathryn E. Hammond¹, Suchandrima Banerjee², Douglas A.C. Kelley², Ahi S. Issever¹, Thomas M. Link¹, Sharmila Majumdar¹

¹Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA; ²Applied Science Laboratory, GE Healthcare, San Francisco, CA, USA

In this work we tested the hypothesis that measurements of intervoxel and intravoxel signal dephasing in the trabecular network can provide important information about the trabecular topological and structural organization at 7T and 3T. We imaged bone specimens with a CHASE sequence on a 7T and 3T whole body MR scanner and analyzed phase measures from the resulting images. We also derived topological and structural measurements from 3D high-resolution peripheral quantitative computed tomography (HR-pQCT) scans at an isotropic voxel size of 41um. Excellent correlations were obtained between MR phase measurements and topological bone parameters measured from HR-pQCT images. We concluded that phase MRI at 7T is feasible and has the ability to provide additional topological and structural information of bone architecture.

                  1947.     Measuring Composition of Bone Marrow by Partial Water and Fat Suppression Proton Projection MRI (WASPI) for Correction of X-Ray Measurement of Bone Mineral Density

Haihui Cao^1,2, Jerome Ackerman^2,3, Melvin Glimcher^1,2, Yaotang Wu^1,2

¹Department of Orthopaedic Surgery, Children's Hospital, Boston, MA, USA; ²Harvard Medical School, Boston, MA, USA; ³Department of Radiology, Massachusetts General Hospital, Boston, MA, USA

Quantitative computed tomography (QCT) is widely used for bone mineral density (BMD) measurements. The variable adipose content of the marrow has been cited to be a major source of measurement error. Knowing the actual marrow composition would help to correct this error. This preliminary study demonstrated that partial WASPI (suppressing either water or fat, but not both at the same time) can provide the information of the ratio of fat/water content in marrow accurately. Partial WASPI measurement can potentially applied in vivo, with an advantage of MRI images registered to QCT images three dimensionally.

                  1948.     Low-SAR Trabecular Bone Micro-MRI for Use at Ultra-High Field

Jeremy F. Magland¹, Alex C. Wright¹, Hamidreza Saligheh-Rad¹, Felix W. Wehrli¹

¹Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, PA, USA

Recent developments in trabecular bone (TB) micro-MRI has allowed 3D structural depiction at resolution sufficient to detect small changes in bone architecture over time. The principle limiting factor to improved resolution is the signal-to-noise efficiency. The introduction of ultra-high field whole body scanners has opened the possibility of increased signal efficiency. However, existing sequences for TB imaging may exceed SAR limits at 7 Tesla. Here we compare two variable echo time, low-SAR alternatives for imaging TB at ultra-high field, one radial and one Cartesian. While each sequence has advantages, the radial sequence gives an overall better image quality, offering a feasible, low-SAR alternative for imaging at 7 Tesla.

                  1949.     Efficient Mechanical Bone Parameter Estimation on the Basis of Grayscale Magnetic Resonance Images

Jeremy F. Magland¹, Chamith Rajapakse¹, X H. Zhang², X E. Guo², Felix W. Wehrli¹

¹Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, PA, USA; ²Department of Biomedical Engineering, Columbia University, New York, NY, USA

While structural trabecular bone parameters combined with bone volume fraction (BV/TV) can be used to predict bone strength beyond that predicted by BV/TV alone, a more direct assessment of strength on the basis of MR images may be found using micro-finite element (µFE) modeling. A custom FE solver, specifically optimized for this application, was implemented in pure C++ and used to estimate mechanical bone parameters on the basis of grayscale images at in-vivo resolution. The algorithm was applied to µ-MR images as well as to µ-CT images downsampled to various resolutions. The results demonstrate the value of retaining grayscale information in the FE computation..

                  1950.     3D Rigid Registration of MRI and HR-PQCT Trabecular Bone Images

Janet Blumenfeld¹, Jenny Folkesson², Galateia Kazakia², Thomas M. Link², Sharmila Majumdar^1,2

¹Bioengineering, UC-Berkeley/UC-San Francisco, San Francisco, CA, USA; ²Radiology, UC-San Francisco, San Francisco, CA, USA

High field MRI and High Resolution peripheral Quantitative Computed Tomography (HR-pQCT) are currently being used to assess trabecular bone structure in-vivo and non-invasively. There exist substantial differences in acquisition and analysis between these two modalities which may influence interpretation of research study results. Studies are being conducted to characterize and quantify these differences. Registration of MRI to HR-pQCT images ensures that the same region is analyzed in both modalities and improves the accuracy of trabecular bone structure comparisons.

                  1951.     Correction of Coil Induced Intensity Inhomogeneities in Magnetic Resonance for Trabecular Bone Analysis

Jenny Folkesson¹, Roland Krug¹, Ahi S. Issever¹, Charles Fang¹, Thomas Link¹, Sharmila Majumdar¹

¹Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA

MRI of osteoporosis-related anatomical locations are generally acquired with a surface coil in order to obtain sufficient sensitivity and resolution for quantification of the trabeculae, however these coils introduces intensity inhomogeneities which affect the analysis of the trabecular bone structure. This work demonstrates the benefits of intensity normalization based coil correction for MRI data acquired with phased array coils in trabecular bone structure analysis compared to low-pass filtering.

                  1952.     Localized Correlated Spectroscopy of Bone Marrow:  Determination of Unsaturation and Apoptosis

S. Sendhil Velan¹, Steven L. Lindauer¹, John Austin Vargo¹, Steven Coon², Raymond R. Raylman¹, Ravinder R. Regatte³, Vazhaikkurichi M. Rajendran², Richard G. Spencer⁴

¹Center for Advanced Imaging and Department of Radiology, West Virginia University, Morgantown, WV, USA; ²Section of Digestive Diseases, Department of Medicine, West Virginia University, Morgantown, WV, USA; ³Center for Biomedical Imaging and Department of Radiology, NYU Medical Center, New York, NY, USA; ⁴Magnetic Resonance Imaging and Spectroscopy Section, NIA, National Institutes of Health, Baltimore, MD, USA

There is a great interest in developing approaches for non-invasive investigation of bone marrow due to its importance in osteoporosis. Degree of unsaturation and apoptosis are highly relevant for diagnosis and treatment interventions of osteoporosis. In this work, we have implemented localized two-dimensional correlated spectroscopic technique to demonstrate the in vivo determination of degree of unsaturation and apoptosis. We have measured the degree of unsaturation and apoptosis in 8 normal-weight subjects.

                  1953.     Tissue-Engineered VEGF-Impregnated Construct to Enhance Angiogenesis for Improved Bone Regeneration: An In-Vivo Longitudinal DCE-MRI Study

Marine Beaumont¹, Marc G. DuVal², Walid A. Farhat³, George K. B Sàndor^2,4, Hai-Ling Margaret Cheng^1,5

¹Research Institute & Diagnostic Imaging, The Hospital for Sick Children , Toronto, Ontario, Canada; ²Oral and Maxillofacial Surgery, University of Toronto, Toronto, Ontario, Canada; ³Research Institute & Urology, The Hospital for Sick Children, Toronto, Ontario, Canada; ⁴Regea Institute for Regenerative Medicine, University of Tampere, Tampere, Finland; ⁵Medical Biophysics, University of Toronto, Toronto, Ontario, Canada

Traditional bone reconstruction requires surgery to harvest bone from the patient, which is limited in supply, potentially painful, and associated with side-effects. Tissue-engineering is a promising technique to overcome these major drawbacks of autogenous bone grafting, but the optimal biomaterials and methods for bone regeneration are not well understood. In this in-vivo longitudinal study, we propose a new regeneration paradigm: inserting a biological soft tissue construct fortified with VEGF to enhance angiogenesis for improved repair of a bony defect. Dynamic contrast-enhanced MRI is shown capable of characterizing angiogenesis and reveals vessel development consistent with successful bone formation.

                  1954.     Age Dependence of Signal Intensity Ratio of In-Phase and Opposed Phase Image in Normal Spinal Bone

Eito Kozawa¹, Naoko Nishi², Youichi Sato², Shinichi Watanabe³, Junji Tanaka²

¹Radiology, Saitama Medical University, Hidaka, Saitama, Japan; ²Radiology, Saitama Medical University, Japan; ³Central Radiology, Saitama Medical University, Japan

We examined 65 normal subjects with 1.5-T MR imaging units on TE of 2.3, and 4.6 msec of dual chemical shift sequence. We divided our subjects into two groups, those younger than 50 years old and those older than 50 years, and we compared the signal intensity ratio (SIR) in the two group. The mean SIRs of the groups were significantly different according to unpaired-test (P < 0.001). Furhermore, in the course of aging, there is a systematic increase in measured of SIR of about 6% per decade of age. In conclusion, the SIR values of normal bone marrow could be strongly influenced by age.

                  1955.     Congenital Malformations of Occipital Vertebrae as Cause of Instability and Degeneration of Atlanto-Axial Joints

Carolina Medeiros Rimkus^1,2, Verônica Araújo Zanardi³, Alberto Cliquet Jr²

¹Radiology and Diagnostic Imaging, State University of Campinas, Sao Paulo, SP, Brazil; ²Orthopaedics Department, State University of Campinas, Campinas, SP, Brazil; ³Radiology and Diagnostic Imaging, State University of Campinas, Campinas, SP, Brazil

Some aspects of the craniocervical junction malformations are trully congenital. But the chronical instability and the articular overload imposed by the skeletal deformities add biomechanical disturbances that can be correlated to acquired disorders. 20.7% of the patients presented atlanto-axial subluxation, correlated to morphological abnormalities classified as manifestations of the occipital vertebrae. Signals of degeneration of the atlanto-axial joints were shown in 42.6%, correlated to atlanto-occipital assimilation.

                  1956.     MRI and PET/CT of Patients with Bone Metastases from Breast Carcinoma

Johan Grankvist¹, Rune V. Fisker¹, Victor Vishwanath Iyer², Finn Taagehøj Jensen¹, Ernst-Torben Fründ^1,3, Carsten Wiberg Simonsen¹, Thorkil Christensen¹, Lars Stenbygaard⁴, Marianne Ewertz Kvistgaard^4,5, Elna-Marie Larsson¹

¹Department of Radiology, Aalborg Hospital / Aarhus University Hospital, Aalborg, Denmark; ²Department of Nuclear Medicine, Aalborg Hospital / Aarhus University Hospital, Aalborg, Denmark; ³GE Healthcare - Applied Science Laboratory Europe; ⁴Department of Oncology, Aalborg Hospital / Aarhus University Hospital, Aalborg, Denmark; ⁵Department of Oncology, Odense University Hospital, Odense, Denmark

This project compares 3T MRI and 18-FDG-PET/CT in patients with bone metastases from breast cancer to the spine and pelvis.

                  1957.     Early Bone Marrow Conversion in Adolescents with Anorexia Nervosa: A T1 Relaxometry Study

Sridhar Vajapeyam¹, Henry Feldman², Kirsten Ecklund¹, Catherine Buzney³, Paul K. Kleinman¹, Robert Vincent Mulkern¹, Catherine Gordon³

¹Radiology, Children's Hospital Boston, Boston, MA, USA; ²Clinical Research Program, Children's Hospital Boston, Boston, MA, USA; ³Medicine, Children's Hospital Boston, Boston, MA, USA

T1-weighted imaging of the knees of adolescent girls with anorexia nervosa (AN) has been found to show consistently higher signal intensity and greater homogeneity in the femur and tibia as compared to normal adolescents, who typically exhibit striations and regions of lower signal, representing red hematopoietic marrow. We performed T1 relaxometry measurements on a cohort of adolescent girls with AN as well as age-matched controls to study this phenomenon. Mean T1 values in distal femoral and proximal tibial metaphyses of anorexics was significantly higher compared to age-matched controls (p=0.04).

                  1958.     T1ρ Mapping of Pediatric Epiphyseal and Articular Cartilage

Jared Guthrie Cobb^1,2, J. Herman Kan³

¹Biomedical Engineering, Vanderbilt University, Nashville, TN, USA; ²Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; ³Radiology and Radiological Sciences, Vanderbilt Children's Hospital, Nashville, TN, USA

The purpose of this study is to determine feasibility of T1ñ mapping of pediatric epiphyseal and articular cartilage. Seven volunteers of age 13 ± 2 years were recruited to have T1ñ mapping performed at the conclusion of their clinical study. T1ñ contrast was generated using a SL pre-pulse developed by Avison. Regions of interest were placed in non-weight-bearing regions of the sagittal slice in the epiphyseal and articular cartilage. Mean values for T1ñ in articular cartilage are reported as 65.1 ± 15.4 ms. Epiphyseal cartilage is reported as 49.3 ± 5.2 ms. Epiphyseal and articular cartilage T1ñ differences may reflect differences in water and glycosaminoglycan composition.

                  1959.     Correlation Between T1ρ MRI and Arthroscopy in Adults with Chondromalacia

Walter RT Witschey¹, Ari Borthakur², Matt Fenty², J. Bruce Kneeland³, Jess Lonner⁴, Erin Leigh McArdle², Ravinder Reddy²

¹Graduate Group in Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, PA, USA; ²Radiology, University of Pennsylvania, Philadelphia, PA, USA; ³Radiology, Pennsylvania Hospital, Philadelphia, PA, USA; ⁴Booth Bartolozzi Balderston Orthopaedics, Pennsylvania Hospital, Philadelphia, PA, USA

To determine whether mild and moderate osteoarthritis (OA) observed during arthroscopy correlates with changes in cartilage as detected with T1rMRI, 9 asymptomatic subjects (2 men and 7 women) and 6 patients (3 men and 3 women) in whom one or more regions of mild or moderate chondromalacia had been demonstrated at arthroscopy were recruited for this study. MRI was performed 2-3 months post-arthroscopy using sagittal T1-weighted and axial and coronal T1r MRI from which spatial T1r relaxation maps were calculated. Statistical analysis of the difference between the asymptomatic subjects and the patients in whom changes of OA had been demonstrated at arthroscopy was performed using multivariate ANOVA and bootstrap confidence interval tests. Correlation between arthroscopy and T1rMRI was determined by either calculating mean compartment T1r or by calculating the mean of a large focally elevated region of T1r within a compartment. Median T1rrelaxation times among symptomatic and asymptomatic subjects were significantly different (p < 0.001) and symptomatic T1r exceeded asymptomatic articular cartilage median T1r by 2.5 to 9.2 ms. Patellar T1r was 2.5-8.3 ms higher than the tibial compartment (p < 0.01). In 8 observations of mild (grade 1 and 2) osteoarthritis at arthroscopy, mean compartment T1r was elevated in 5, but in all cases, large foci of increased Tr were observed. In 6 cases of moderate or severe chondromalacia, compartment mean T1r was always elevated. T1r MRI correlated with arthroscopically confirmed diffuse or focal chondral damage and may be used to noninvasively detect early changes of OA in cartilage.

                  1960.     Assessment of Cartilage T1ρ Values in Osteoarthritic Patients with and Without Meniscal Tears at 3T

Ligong Wang¹, Mark E. Schweitzer¹, Ravinder R. Regatte¹

¹Radiology, NYU Langone Medical Center, New York, NY, USA

The purpose of this work was to assess cartilage T1rho values in osteoarthritic patients with and without meniscal tears at 3T. OA patients without meniscal tears (n = 5) and with mensical tears (n = 5) were scanned. The preliminary results suggest that there are significant differences in T1rho relaxation times between the two groups specifically within the lateral compartment (P < 0.05) but not in the medial compartment (P > 0.05).

                  1961.     Feasibility and Reproducibility of T_1ρ MRI Examining Osteoarthritis in a Guinea Pig Model

Matthew Fenty¹, Erin McArdle¹, Victor Kassey¹, Walter RT Witschey 2nd^1,2, Arijitt Borthakur¹, Ravinder Reddy

¹Radiology, University of Pennsylvania, Philadelphia, Pa, USA; ²Graduate Group in Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, Pa, USA

Feasibility and reproducibility of T1p; MRI was assessed in spontaneously developing osteoarthritis in Dunkin Hartley guinea pigs. A high degree of precision of intra- and inter- animal T1p measurement and age-dependent increase in T1p values is demonstrated.

                  1962.     Intra- And Inter-Scanner Variability of Knee Cartilage T2 in Human Knees at 3.0T: A Multivendor Comparison Study

Sharon Balamoody¹, Charles Edward Hutchinson¹, John C. Waterton^1,2, Tomos G. Williams¹, Michael Bowes³, Richard Hodgson⁴

¹ISBE, University of Manchester, Manchester, UK; ²AstraZeneca, Alderly Edge, Cheshire, UK; ³Imorphics, Manchester, UK; ⁴MARIARC, University of Liverpool, Liverpool, UK

Cartilage T2 was measured in twelve subjects with symptoms of knee osteoarthritis using Philips, Siemens and GEHC platforms at 3.0T. In knees, Philips intra-scanner R2 RMS COVs were <3% (intra-session) and 3.2-6.3% (inter-session). GE knee T2 values were systematically lower compared to the other scanners. Results from the phantom study did not predict in vivo results.

                  1963.     Practical T2 Mapping of Cartilage in a Rabbit Model of Hemophilic Arthropathy

Afsaneh Amirabadi¹, Elka Miller², Logi Vidarsson¹, Marshall S. Sussman^3,4, Hai-Ling Margaret Cheng^4,5, Andrea S. Doria^1,4

¹The Hospital for Sick Children, Toronto, Ontario, Canada; ²Hamilton Health Sciences, McMaster site, Hamilton, Canada; ³Toronto General Hospital, the University Health Network, Toronto, Ontario, Canada; ⁴University of Toronto, Toronto, Ontario, Canada; ⁵The Hospital for Sick Children , Toronto, Ontario, Canada

Early treatment of hemophilia, an inherited bleeding disorder, has been shown to reduce cartilage degeneration and long-term joint morbidity. Conventional T2 maps can be time consuming and non-feasible in clinical practice. In this study we validated a new short-TR T2 map technique for assessment of early cartilaginous changes over time in knees of a rabbit model of hemophilic arthritis. This technique proved to be a sensitive marker for detection of organizational changes in articular cartilage over time, correlating well with histological indexes of cartilage damage. Concomitant administration of USPIO contrast material overestimates the decrease of T2 map values over time.

                  1964.     Bi-Exponential T2* Mapping of the Knee Cartilage: Results on Explants

Yongxian Qian¹, Ashley A. Williams², Constance R. Chu², Fernando E. Boada¹

¹Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA; ²Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA

This study presents initial experimental results of bi-exponential T2* mapping of human knee cartilage explants, based on ultra-short echo time (UTE) images acquired on a clinical 3T scanner. The non-negative least squares (NNLS) algorithm was used to identify bi-T2* decay at selected pixels while Monte Carlo simulations were implemented for optimizing the design of TE series needed in the bi-T2* mapping. The bi-exponential T2* mapping of healthy and diseased knee cartilage explants were demonstrated to show the difference in short-T2* time and population between healthy and diseased explants.

                  1965.     Depth-Wise Modulation of T₂ Relaxation Time in Articular Cartilage Degeneration

Mikko Johannes Nissi^1,2, Petro Kalle Julkunen¹, Miika Tapio Nieminen^3,4, Jukka Sakari Jurvelin²

¹Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland; ²Department of Physics, University of Kuopio, Kuopio, Finland; ³Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland; ⁴Department of Radiology, University of Oulu, Oulu, Finland

Depth-wise T₂ relaxation time of articular cartilage reveals laminar tissue structure that closely associates with the properties of the collagen fibril network. To determine the depth-wise T₂ changes in cartilage degeneration, T₂ profiles were determined for intact bovine patellar cartilage, as well as for samples with early or advanced degeneration. T₂ profiles for different groups were compared in a point-wise manner at different depths. The results indicate that significant changes occur in degeneration both at the most superficial and deep parts of the tissue. Furthermore, the results showed that the detectable depth-wise structure may vary with degeneration.

                  1966.     The Influence of Chemical Shift Artifacts on Cartilage T2 Mapping

Toshiyuki Shiomi¹, Takashi Nishii^1,2, Hisashi Tanaka³, Mina Okamoto¹, Hideki Yoshikawa¹, Nobuhiko Sugano^1,2

¹Department of Orthopaedic Surgery, Osaka University Medical School, Suita, Osaka, Japan; ²Department of Orthopaedic Medical Engineering, Osaka University Medical School, Suita, Osaka, Japan; ³Department of Radiology, Osaka University Medical School, Suita, Osaka, Japan

The purpose of this study is to compare preventing effects of chemical shift artifacts in T2 mapping between those proposed techniques, using cadaver porcine femoral condyles with normal cartilage and cartilage partially depleted of matrix components, and to correlate with biochemical composition.

                  1967.     The Relationship Between the Spatial Distribution of Cartilage MR T₂ and Longitudinal Changes in Pain: Data from the Osteoarthritis Initiative

Gabrielle Blumenkrantz¹, Julio Carballido-Gamio², Charles E. McCulloch³, John A. Lynch³, Thomas M. Link², Sharmila Majumdar¹

¹Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA; ²Department of  Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA; ³Department of  Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA

The purpose of this study is to [1] examine changes in MR knee cartilage parameters including thickness, T₂, and spatial distribution of cartilage T₂ and [2] examine whether these baseline MR parameters predict change in knee pain over two years. The results indicate a significant decrease in cartilage thickness over two years. Of all MR parameters evaluated (including cartilage thickness and mean T₂), only the baseline entropy of cartilage T₂ was significantly associated with longitudinal rate-of-change in pain.

                  1968.     Quantifying the Progression of Osteoarthritis with MRI:  Quantitative T2 Changes in Articular Cartilage Over a 2 Year Time Period.

Adilakshmi Kansal¹, Kathleen Hughes¹, Nabile Safdar¹, George Makris², Alan McMillan¹, Rao Gullapalli¹

¹Magnetic Resonance Research Center, Department of Radiology, University of Maryland Medical Center, Baltimore, MD, USA; ² Magnetic Resonance Research Center, Department of Radiology, University of Maryland Medical Center, Baltimore, MD, USA

MRI is important in the assessment of articular cartilage. Previous studies have suggested that alterations in cartilage water content occur prior to irreversible destruction. The purpose of our study was to retrospectively acquire T2 maps in 3 cartilaginous locations from an initial baseline MRI, and to compare these findings with a two year follow-up MRI, in both healthy and osteoarthritis patients from a subset of subjects from the Osteoarthritis Initiative study. Our study demonstrated that the T2 values of the medial femoral condyle in the progression cohort were significantly higher on follow up MRI in comparison to the baseline examination.

                  1969.     Fast 3D UTE Imaging of Knee Connective Tissues on a Clinical 3T Scanner

Yongxian Qian¹, Ashley A. Williams², Constance R. Chu², Fernando E. Boada¹

¹Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA; ²Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA

This abstract introduces a new fast 3D ultra-short echo time (UTE) pulse sequence (AWSOS, acquisition-weighted stack of spirals) for knee imaging and demonstrates its performance with in vivo images of knee cartilage, menisci, and ligaments in healthy volunteers acquired at 3T.

                  1970.     New Strategies for Clinical Trials of OA: Evidence from a Longitudinal Trial of Radiography, MRI Morphometry and Molecular MRI

Deborah Burstein^1,2, Felix Eckstein^3,4, Nitya Krishnan¹

¹Radiology, Beth Israel Deaconess Medical Center, Boston, MA, USA; ²Harvard-MIT Division of Health Sciences and Technology , Boston, MA, USA; ³Paracelsus Medical University, Institute of Anatomy and Musculoskeletal Research, Strubergasse 21A 5020, Salzburg, Austria; ⁴Chondrometrics GmbH, Ainring, Germany

Data from a 2 year trial of radiography, MRI morphometry, and dGEMRIC are utilized to delineate potential new strategies for trials of OA. Indications that not all KLG0 may be “healthy controls”, that “fast progressors” are in all KL groups, and that progression occurs in many knees with thin cartilage in KLG3, suggest strategy that KLG alone may not be optimal for defining cohorts for clinical trials. dGEMRIC lesions which receded suggest a strategy of investigating “vulnerable” cartilage. Finally, findings indicate that there may be an effect on cartilage at the “entry” (first 3 months) of a clinical trial.

                  1971.     Assessment of the Radial Distribution of Glycosaminoglycans (GAG) in Arthritic Hips Using Delayed Gadolinium Enhanced MRI of Cartilage (DGEMRIC)

Jenny Chan¹, Samir Sur¹, Inge Kress¹, Tallal Charles Mamisch², Young-Jo Kim¹

¹Orthopaedics, Children's Hospital Boston, Boston, MA, USA; ²University of Berne, Berne, Switzerland

The radial distribution of glycosaminoglycan (GAG) in 35 arthritic hips was assessed using a three-dimensional isotropic fast T1 mapping sequence for dGEMRIC. Hips with mild osteoarthritis had the highest GAG concentration in the superior regions of the joint cartilage, while those with severe OA displayed an inverse pattern. The study also shows that thin slice dGEMRIC sequencing produced similar results to the previously validated fast T1 mapping using thick coronal slices. We conclude that the 3D dGEMRIC is a powerful diagnostic tool that can be used in vivo to characterize the patterns of cartilage damage in early OA.

                  1972.     Three-Dimensional Magnetic Resonance Observation of Cartilage Repair Tissue (3D MOCART) Score Assessed with an Isotropic 3D-True-FISP Sequence at 3.0 Tesla

Goetz Hannes Welsch¹, Lukas Zak², Tallal Charles Mamisch³, Christoph Resinger², Stefan Marlovits², Siegfried Trattnig¹

¹MR Center, Department of Radiology, Medical University of Vienna, Vienna, Austria; ²Center for Joint and Cartilage, Department of Trauma Surgery, Medical University of Vienna, Vienna, Austria; ³Department of Orthopedic Surgery, University of Berne, Berne, Switzerland

Cartilage defects are common pathologies and surgical cartilage repair shows promising results. In its post-operative evaluation, the magnetic resonance observation of cartilage repair tissue (MOCART) score is widely used. Within the present study a newly developed 3D-MOCART score was presented. 100 Knee MRIs in 60 patients were included during a routine MR follow-up examination at 3.0 Tesla MRI using an high-resolution isotropic 3D-true fast-imaging with steady-state-precession (True-FISP) sequence for the new 3D-MOCART score in the post-operative evaluation of patients after matrix-associated autologous chondrocyte transplantation. Finally, the results were compared to the conventional 2D-MOCART score using standard MR sequences.

                  1973.     Effect of High Tibial Osteotomy on Patellar Cartilage Health: A DGEMRIC Study

Agnes G. d'Entremont¹, Burkhard Madler², Simon Horlick³, Mojieb Manzary³, Trevor Stone³, Robert G. McCormack³, David R. Wilson³

¹Mechanical Engineering, University of British Columbia, Vancouver, BC, Canada; ²Philips Medical Systems; ³Orthopaedics, University of British Columbia

High tibial osteotomy (HTO) is a treatment for medial TF OA that changes joint biomechanics. HTO has been shown to alter mechanics in both the TF and PF joints. Our objective was to determine how the mechanical change produced by HTO affects PF cartilage. Seven subjects had dGEMRIC scans before surgery, and at 6- and 12-month follow-ups. We saw several patterns of change, the predominant one being a decrease in dGEMRIC index at 6 months, followed by a smaller increase at 12 months. The variety of dGEMRIC changes produced by HTO may reflect subject-specific mechanical changes of the surgery.

                  1974.     Repeatability of T1-Quantification in DGEMRIC for Three Different Acquisition Techniques: 2D-Inversion Recovery, 3D-Look-Locker and 3D-Variable Flip Angle

Carl Siversson¹, Carl-Johan Tiderius², Paul Neuman², Leif Dahlberg², Jonas Svensson¹

¹Department of Radiation Physics, Lund University, Malmo, Sweden; ²Department of Orthopaedics, Lund University, Malmo, Sweden

Delayed Gadolinium enhanced MRI of cartilage (dGEMRIC) is a technique for molecular imaging of the proteoglycan level in cartilage using T1 quantifications. Until now there have been no studies of the repeatability of such T1 quantifications in 3D. Measurements were performed twice on the same knee, with two weeks separation, on 9 subjects using 2D-Inversion Recovery (2D-IR), 3D-Look Locker (3D-LL) and 3D-Variable Flip Angle (3D-VFA) methods. The 2D-IR and 3D-LL sequences perform roughly equally well, thus verifying the stability of the 3D-LL sequence. With 3D-VFA there is a considerably larger deviation than with the other sequences.

                  1975.     Repeatability and Age-Related Change of Sodium in the Knee Articular Cartilage Measured with Sodium MRI

Seungbum Koo¹, Ernesto Staroswiecki^1,2, Neal Bangerter³, Brian Hargreaves¹, Garry Gold¹

¹Radiology, Stanford University, Stanford, CA, USA; ²Electrical Engineering, Stanford University, Stanford, CA, USA; ³Electrical & Computer Engineering, Brigham Young University, Provo, UT, USA

Sodium MRI is sensitive to proteoglycan loss in cartilage. The goals of this study were twofold: to attempt to identify any age-related change of sodium signal in the knee cartilage, and to assess the repeatability of sodium signal measurements in cartilage at two time points. Fifteen subjects (ages 21 to 48 years) were scanned using sodium MRI. This relatively young population did not show age-dependent change in cartilage sodium signal but their medial tibiofemoral cartilage had significantly higher sodium signal than other regions. The average variability of the cartilage sodium signal within 48 hours was 6.6%.

                  1976.     Deformation of Cartilaginous Collagen Fiber Network Under Pressure: A Load-Bearing MRI Study.

Nikita Garnov^1,2, Wilfried Gründer²

¹Department of Diagnostic and Interventional Radiology, University Hospital Leipzig, Leipzig, Germany; ²Institute of Medical Physics and Biophysics, University of Leipzig, Leipzig, Germany

Collanopsisgen fibres together with proteoglycans and water form a three-dimensional network of articular cartilage and provide this tissue its unique biomechanical properties. Mechanical stress leads to deformations of collagen matrix which have been assessed by microscopic studies. A crimping or a bending of collagen fibres under pressure was observed. However, the deformation included the bending and the crimping was also described. In the present work, the load conditioned changing of collagen fiber orientation by means of T₂-weighted MR images was observed. In this way, the cartilage matrix deformation at nearby in-vivo-conditions could be considered.

                  1977.     Identification of Degenerative Cartilage Through Use of Multiparametric Discriminant Analysis and the Support Vector Machine

Ping-Chang Lin¹, Richard G. Spencer¹

¹National Institute on Aging, National Institutes of Health, Baltimore, MD, USA

MRI is increasingly employed as a means of describing cartilage; however, using univariate analysis has limitedly succeeded to classify tissue into normal and degraded groups due to a large degree of overlap in distributed parameter values. We extend the simple arithmetic means procedure by including multivariate model-based discriminant and support vector machine analyses applying on the control puls trypsin or collagenase digested cartilage samples. Results from these three approaches are analyzed according to their sensitivities and specificities. Classification accuracy is markedly improved by either one of these two multivariate procedures, compared to the best uni-parametric MR discriminator.

                  1978.     Validation of Cartilage Thickness Calculations Using Indentation Analysis

Matthew F. Koff¹, LeRoy Chong², Patrick Virtue³, Dan Chen⁴, Timothy Wright⁴, Hollis Potter¹

¹Department of Radiology and Imaging, Hospital for Special Surgery, New York, NY, USA; ²Department of Diagnostic Radiology, Changi General Hospital, Singapore; ³GE Healthcare, Waukesha, WI, USA; ⁴Department of Biomechanics, Hospital for Special Surgery, New York, NY, USA

Magnetic resonance imaging (MRI) can be used for non-invasive quantification of cartilage distribution within a joint. A limited number of cartilage thickness validation studies have been performed. The goal of this study was to perform a matching point-to-point validation of indirect cartilage thickness calculations from MR images with direct cartilage thickness measurements using biomechanical indentation. A phantom was used to register data from the image and the indentation coordinate systems. Differences between the methods of cartilage thickness measurement were 0.047+/-0.218 mm (mean+/-st.dev.). This study will aid in validating a tool for clinical evaluation of in-vivo cartilage thickness.

                  1979.     Feasibility of Magnetization Transfer Ratio of the Patellar Articular Cartilage at 3T

Shuji Nagata^1,2, David W. Stanley³, Steven L. Williams², Marilyn M. Wood², Joel P. Felmlee², Hiroshi Nishimura⁴, Naofumi Hayabuchi¹, Kimberly K. Amrami²

¹Radiology, Kurume University Hospital, Kurume, Fukuoka, Japan; ²Radiology, Mayo Clinic, Rochester, MN, USA; ³GE healthcare, USA; ⁴Saiseikai Futsukaichi Hospital, Fukuoka, Japan

Magnetization transfer ratio (MTR) is a biochemical analysis technique and it has been concluded the structure and concentration of the collagen matrix are the predominant determinants of magnetization transfer process in cartilage. The aims of this study were to evaluate the feasibility of MTR with a 3T clinical MR imager, to measure MTR at different places of patellar cartilage, and to compare MTR with degree of chondromalacia. MTR would be sensitive to alterations in collagen structure and could be used as an indicator of prediction of cartilage degeneration.

                  1980.     Longitudinal In Vivo Evaluation of Articular Cartilage Injuries in Small Animals Using Quantitative MR Imaging

Carmen Taylor¹, Ryan Doan^1,2, Alexis Dang³, Sharmila Majumdar¹, C Benjamin Ma³

¹Radiology, University of California, San Francisco, San Francisco, CA, USA; ²Cleveland Clinic Lerner College of Medicine, Cleveland, OH, USA; ³Orthopedics, University of California, San Francisco, San Francisco, CA, USA

In osteoarthritis (OA), high field MRI allows a quantitative measure of volumetric and biochemical changes of cartilage. Human studies have shown that T1r and T2 mapping techniques have the ability to provide highly accurate and quantitative measurements[1] of articular cartilage degeneration in vivo. However, the development of pharmaceuticals to treat OA rests on the characterization of disease states in small animals, and this characterization is best done longitudinally to avoid confounding factors such as individual variation. Towards this end, we have characterized the rabbit anterior cruciate ligament (ACL) transection model of OA longitudinally in vivo over 12 weeks using T1r and T2 mapping techniques, and we have used this model to assess the effects of the common antibiotic doxycycline[2] on OA progression.

                  1981.     HR-MAS Spectral Analysis of Osteoarthritic Cartilage

Sarmad Muneeb Siddiqui^1,2, Rahwa Iman², Jan Wooten², John Kurhanewicz², Michael Ries³, Xiaojuan Li²

¹University of California, Berkeley, Berkeley, CA, USA; ²Radiology, University of California, San Francisco, San Francisco, CA, USA; ³Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA, USA

Osteoarthritis (OA) is a multifactorial disease that is characterized primarily by the progressive loss of articular cartilage. Current radiological imaging techniques are limited to observing morphological changes that occur at relatively late stages of the disease. However, the biochemical composition of cartilage changes even in early stages of the disease. The goal of this study is to determine whether there are any significant, detectable changes in the spectra of healthy and osteoarthritic human cartilage using HRMAS spectroscopy. Results suggest that there were significant differences in cartilage biomarkers such as Choline, Alanine, and Glycine, between OA and healthy cartilage.

                  1982.     MRI Assessment of Matrix Development in Ultrasound-Treated Cartilage Constructs

Onyi Irrechukwu¹, Ping-Chang Lin¹, David Reiter¹, Ligaya Roque¹, Steve Doty², Richard Spencer¹, Kenneth Fisbein¹, Nancy Pleshko³

¹National Institute on Aging, National Institutes of Health, Baltimore, MD, USA; ²Department of Orthopaedics, Hospital for Special Surgery, New York, NY, USA; ³Exponent Inc., Philadelphia, PA, USA

The objective of this study was to use MRI as a tool to probe the effect of ultrasound stimulation of engineered cartilage. Chondrocyte-seeded collagen constructs were stimulated with ultrasound for 3 weeks while in culture. Longitudinal (T1) and transverse (T2) relaxation times and magnetization transfer rate (km) were obtained from the analysis of decay curves. T2 decreased while km increased in treated samples indicating an increase in the macromolecular content of constructs with ultrasound stimulation. These results were consistent with the greater sulphated glycosaminoglycan content measured biochemically and the more intense Alcian-blue staining visualized in treated samples.

                  1983.     MRI Assessment of Temporal Soft Tissue and Bone Changes in Murine Collagen-Induced Arthritis

Andreas Pohlmann^1,2, Victor Musoko², Olga Woolmer³, Alison Robinson³, Jackie Buckton⁴, Anthony R. Hobson⁴, Michael F. James²

¹Academic DPU, GlaxoSmithKline R&D Ltd, Cambridge, UK; ²Immuno-Inflammation CEDD, GlaxoSmithKline R&D Ltd, Harlow, UK; ³Laboratory Animal Science, GlaxoSmithKline R&D Ltd, Harlow, UK; ⁴Immuno-Inflammation CEDD, GlaxoSmithKline R&D Ltd, Stevenage, UK

In murine collagen-induced arthritis (CIA) visual scoring of arthritic changes in the paws is commonly used to assess disease severity and therapeutic efficacy. We developed quantitative in vivo MRI of hindpaw changes and studied the temporal progression of CIA. Analysis of contrast-enhanced T1-weighted MRI yielded volumes of enhancing tissue, soft tissue, and bone, which were directly compared with conventional scoring procedures. Significant increases with time in all measures were observed, except for bone, which only showed weak trends towards degradation. MRI may offer an objective and quantitative alternative to conventional biomarkers in CIA.

                  1984.     Partially Spoiled Dual Echo Steady State Acquisitions (PDESS)

Oliver Bieri¹, Carl Ganter², Francesco Santini¹, Klaus Scheffler¹

¹Division of Radiological Physics, University of Basel Hospital, Basel, Switzerland; ²Department of Diagnostic Radiology, Klinikum rechts der Isar, Technical University Munich, Munich, Germany

The theory and effect of partial spoiling is extended from SSFP-FID to SSFP-echo. SSFP-echo has found application in diffusion weighted imaging and is of special interest in combination with SSFP-FID as dual echo steady state (DESS) acquisition for joint imaging. We will show that partial spoiling of dual echo steady state (pDESS) acquisitions is beneficial for improved morphological mapping of cartilage.

                  1985.     Balanced SSFP Profile Asymmetries in Cartilage

Nikola Stikov¹, Kathryn E. Keenan², Karla L. Miller³, Joelle Karine Barral¹, Garry Evan Gold⁴, John Mark Pauly¹

¹Electrical Engineering, Stanford University, Stanford, CA, USA; ²Mechanical Engineering, Stanford University, Stanford, CA, USA; ³FMRIB Centre, Oxford University, Oxford, Oxon, UK; ⁴Radiology, Stanford University, Stanford, CA, USA

Osteoarthritis of the knee affects approximately 30% of the American population over 60. Currently osteoarthritis cannot be detected until after significant cartilage degradation. Early detection of reduced glycosaminoglycans (GAGs) in cartilage would be useful for early diagnosis of osteoarthritis. The gagCEST contrast mechanism succeeds in imaging GAGs thanks to their asymmetric z-spectrum. An alternative way to capture this asymmetry is by using a balanced SSFP sequence, because the SSFP frequency profile is affected by the lineshape of the tissue. Recently it has been shown that the SSFP profile of white matter in the brain has an asymmetry in its frequency profile. We observed similar asymmetry in cartilage using the balanced SSFP technique.

                  1986.     Isotropic Imaging of the Wrist at 1.5T Using 3D-FSE-Cube

Kathryn Jane Stevens¹, Grant Charles Wallace¹, Weitian Chen², Reed F. Busse², Anja CS Brau², Philip J. Beatty², Garry Evan Gold¹

¹Radiology, Stanford University Medical Center, Stanford, CA, USA; ²GE Healthcare, GE Healthcare Global Applied Sciences Laboratory, Menlo Park, CA, USA

Two-dimensional fast spin-echo (2D-FSE) is frequently used to evaluate the wrist joint, but is limited by partial volume artifacts and slice gaps. Volumetric acquisition with isotropic resolution overcomes these limitations, and allows reformations in multiple imaging planes from a single acquisition. We compared 2D-FSE in the wrist at 1.5T with 3D-FSE-Cube, a technique that combines variable flip angle refocusing with auto-calibrated parallel imaging to achieve isotropic resolution in clinical feasible scan times. 3D-FSE-Cube showed significantly higher signal-to-noise than 2D-FSE, and fat suppression was uniform. The ability to reformat in any plane makes multiple 2D acquisitions unecessary, and also enhances visualization of complex wrist anatomy.

                  1987.     High-Resolution Uniform Imaging of Finger Joints Using a Dedicated RF Coil at 3.0T

Wingchi Edmund Kwok¹, Zhigang You¹, Johnny Monu¹, Gwysuk Seo¹

¹Department of Imaging Sciences, University of Rochester, Rochester, NY, USA

Insufficient resolution in MRI of finger joints can hinder early diagnosis of arthritic diseases. We developed a dedicated RF receiver coil for high-resolution uniform MRI of fingers at 3T. Phantom studies show that the dedicated cylindrical coil provides higher and more uniform signal compared to a planar coil of similar size. Using the dedicated coil, in vivo and in vitro 3D images of finger joints were obtained using isotropic resolution of 160 microns under 10minutes. These images reveal detailed structures of the whole finger joint. Our technique should be useful for early diagnosis, treatment assessment and basic research of arthritides.

                  1988.     A Comparison of Wrist MRI at 3T and 7T Using Adjustable Receiver Arrays

Jurek A. Nordmeyer-Massner¹, Michael Wyss¹, Gustav Andreisek², Juerg Hodler³, Klaas P. Pruessmann¹

¹Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland; ²Institute for Diagnostic Radiology, University Hospital Zurich, Zurich, Switzerland; ³Departement of Radiology, Balgrist University Hospital , Zurich, Switzerland

We present a comparison of wrist MRI at 3T and 7T using geometrically identical mechanically adjustable coil arrays. The analysis includes qualitative and quantitative measures. SNR maps incorporating the effects of coil-to-coil noise correlation were calculated and analyzed by defining regions of interest (ROI) in clinically relevant regions including cartilage layers between carpal bones, the trabecular bone structure of the os lunatum, the triangular fibrocartilage complex (TFCC) and the median nerve. In general the SNR was higher at 7T than at 3T although the gain was less pronounced than might by expected from the mere field strength ratio.

                  1989.     B1 Inhomogeneity Corrected T1-Quantification for DGEMRIC Using 3D Look-Locker Technique with Non-Slice Selective RF-Pulses

Carl Siversson¹, Carl-Johan Tiderius², Leif Dahlberg², Jonas Svensson¹

¹Department of Radiation Physics, Lund University, Malmo, Sweden; ²Department of Orthopaedics, Lund University, Malmo, Sweden

3D Look-Locker (LL) can be used for various T1 quantification applications, such as delayed Gadolinium enhanced MRI of cartilage (dGEMRIC). The LL method is however usually dependent on both the excitation- and inversion pulse performing well in order to generate reliable T1 values. By using non-slice selective rectangular RF pulses for excitation and inversion, both having a similar B1 dependence, it is possible to map and compensate for all B1 inhomogeneities. With this method the measured T1 is very accurate throughout all slices, both in gel phantoms and in in vivo dGEMRIC measurements.

                  1990.     A Noval Algorithem for Eddy Current Effect Reduction in Dixon Method

Dongmei Wu¹, yongming Dai², kecheng Liu³

¹Application, Siemens Mindit Magnetic Resonance Ltd., Shenzhen, GuangDong, China; ²MR Business, Siemens Ltd, China, Shanghai, China; ³Siemens Medical solution, U.S, Cleveland, OH, USA

For the time limit, "Bipolar" mode gradient used for three point dixon method on high field MR system will result in the k-space misalignment for the cause of eddy current. And the misalignment will bring addition phase in image space,which will contaminate the chemical-shift phase, and lead to the failure of fat water separation. This abstract adapt a novel methods which correct this kind k-space misalignment through dealing with the phase discrepancy in image space..

                  1991.     Maximizing RF Signal in the Presence of Rapid T2 Relaxation

Michael Carl¹, Mark Bydder², Atsushi Takahashi¹, Eric Han¹, Graeme Bydder²

¹GE Healthcare, Applied Science Lab, Milwaukee, WI, USA; ²Radiology, University of California, San Diego, CA, USA

When using UTE methods to image short or ultra short T2 species, such as ligaments, tendons or cortical bone, the intrinsic T2 can be on the same order as ô, and the signal decay during the RF pulse may no longer be ignored. In this work we derive a generalized Ernst angle equation to select a nominal flip angle (for a given maximum B1) that maximizes signal amplitude for these circumstances. In addition, we derive an analytic expression for an effective TE for short T2 species.

                  1992.     Towards Whole Body Magnetic Resonance Imaging at Ultra-Low Fields

Karlene Rosera Maskaly¹, Michelle A. Espy¹, John J. Gomez¹, Andrei N. Matlachov¹, Shaun G. Newman¹, Mark V. Peters¹, J Henrik Sandin¹, Larry J. Schultz¹, Algis V. Urbaitis¹, Petr L. Volegov¹, Vadim S. Zotev¹

¹Applied Modern Physics, Los Alamos National Laboratory, Los Alamos, NM, USA

After successfully demonstrating the first ultra-low field (ULF) magnetic resonance images of a human brain, our group has proceeded with the further development of this technology towards achieving whole-body imaging. A new custom-built apparatus was manufactured that is capable of imaging any part of the human body for a small adult subject. Using this setup, we obtained ULF magnetic resonance images of several soft tissues, including anterior knee images. In addition, we also calculated relaxation times at low field strengths. In this presentation, these results will be reviewed, along with future directions we plan to take this work.

                 1993.     Skin Imaging at 7T

Joelle Karine Barral¹, Ronald D. Watkins², Bob S. Hu³, Dwight George Nishimura¹

¹Electrical Engineering, Stanford University, Stanford, CA, USA; ²Radiology, Stanford University, Stanford, CA, USA; ³Palo Alto Medical Foundation, Palo Alto, CA, USA

High-resolution skin imaging is a natural application of high-field systems. Small surface coils can be used which do not suffer from standing wave artifacts commonly seen with larger coils. Using a 1-inch diameter Tx/Rc coil, we compared different pulse sequences at 7T when imaging the calf of a healthy volunteer. Images up to 117x177x500 µm3 resolution are presented and trade-offs are discussed.

                  1994.     A Novel Figure-Eight Coil for Skin Imaging at 7T

Stefan Maderwald^1,2, Stephan Orzada^1,2, Andreas K. Bitz^1,2, Oliver Kraff^1,2, Irina Brote^1,2, Jens M. Theysohn^1,2, Mark E. Ladd^1,2, Susanne C. Ladd^1,2, Harald H. Quick^1,2

¹Erwin L. Hahn Institute for MRI, Essen, Germany; ²Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany

The high SNR of 7 T MRI in conjunction with a new figure-eight transmit/receive skin coil with a quadratic surface area of 7 x 7 cm2 opens up new perspectives for the noninvasive imaging and characterization of human skin. In-vivo MRI with high resolution (voxel volumes of 10-2 mm3 and smaller) was successfully performed in four healthy volunteers and was feasible within short examination times. The images were compared to a commercial 7-cm-inner-diameter single-loop transmit/receive coil. The custom-built skin coil combines a large FOV and restricted penetration depth with higher SNR and signal homogeneity.

                  1995.     Assessment of Magnetization Transfer Ratio, Diffusion Weighted Image, and T2-Weighted Image in Human Median Nerve at 3T: Comparison with Carpal Tunnel Syndrome

Shuji Nagata^1,2, David W. Stanley³, Steven L. Williams², Marilyn M. Wood², Suk-Joo Hong^2,4, Joel P. Felmlee², Kimberly K. Amrami²

¹Radiology, Kurume University Hospital, Kurume, Fukuoka, Japan; ²Radiology, Mayo Clinic, Rochester, MN, USA; ³GE healthcare, USA; ⁴Korea University, Seoul, Korea

The aims of this study were to assess normative values for median nerve magnetization transfer ratio (MTR), apparent diffusion coefficient (ADC), fractional anisotropy (FA), cross sectional area (CSA), flatness ratio (FR), and signal-to-noise ratio (SNR), and to compare them with those of a patient with proven carpal tunnel syndrome (CTS). These normative values of the median nerve collected can be used as a reference for further studies in evaluating the role of these quantitative MR measurements in the evaluation, diagnosis, and follow-up of CTS.

                  1996.     Feasibility of Sagittal T2 Mapping of Human Median Nerve for Localization of Abnormal Region in Patients with Carpal Tunnel Syndrome

Yukari Takeyasu¹, Takashi Nishii², Tsuyoshi Murase¹, Toshiyuki Shiomi¹, Hisashi Tanaka³, Youichi Yamazaki⁴, Kenya Murase⁴, Hiroyuki Tanaka¹, Jyunichi Miyake¹, Hideki Yoshikawa¹

¹Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; ²Department of Orthopaedic Medical Engineering, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; ³Department of Radiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; ⁴Department of Medical Physics & Engineering, Osaka University Graduate School of Medicine, Suita, Osaka, Japan

In previous studies the cross-sectional area of CTS and median nerve were mostly evaluated on axial MR images, and there were few reports regarding sagittal MR images of the median nerve, presumably owing to difficulty in localization of the nerve. The present study showed that T2 abnormality was not correlated with morphological shape of the median nerve (flattening ratio), and was in accordance with the finding of Simon et al. Interestingly, localization of most abnormal T2 region in the median nerve differed among patients, in spite of generally accepted opinion that distal portion of the carpal tunnel is prone to entrapment. In conclusion, sagittal T2 mapping is feasible for identifying abnormal T2 region of the median nerve, presumably relating with nerve damage (swelling, edema, or disturbance of nerve fiber arrangements).

                  1997.     Mapping of Intervertebral Disc Long and Short T₂* Components at 7T

Chenyang Michael Wang¹, Mark Elliott², Tom Connick, Walter Witschey³, Abram Voorhees⁴, Joe Calabro⁴, Erin McArdle, Ari Borthakur², Ravi Reddy²

¹Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; ²Radiology, University of Pennsylvania; ³Biophysics and Molecular Biology, University of Pennsylvania; ⁴Siemens Healthcare

Sodium MRI is highly sensitive to the initial stage of intervertebral disc degeneration, which involves the break down of proteoglycans. Sodium MRI applications are limited by its inherent low SNR. We took advantage of higher magnetic field strength and ultra short TE pulse sequences to increase SNR of bovine intervertebral disc MRI. In addition, we obtained separately the T2* and spin densities of the long and short T2* components. The ability to separately quantify relaxation parameters of the long and short T2* components would improve the accuracy of tissue sodium measurement using phantoms of known sodium concentration.

                  1998.     T2 Mapping as a Potential Biomarker in a Rabbit Model of Intervertebral Disk Damage and Degeneration

Harvey Edward Smith¹, Sukhoon Oh², D Greg Anderson¹, Patti A. Miller², Yejia Zhang³, Lindsi DeArment², Neal Fitzpatrick², Joseph Hong¹, Todd J. Albert¹, Alexander R. Vaccaro¹, Alan S. Hilibrand¹, Christopher M. Collins²

¹Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, PA, USA; ²Radiology, Pennsylvania State University, Hershey, PA, USA; ³Physical Medicine and Rehabilitation, Thomas Jefferson University, Philadelphia, PA, USA

T2-weighted images and T2 maps of intervertebral disks are investigated for use as biomarkers in a rabbit model of disk damage and degeneration. T2 proves to be an effective indicator of damage/degeneration of intervertebral disks. Ongoing work includes the use of T2 to evaluate recovery/regeneration in treatment with various agents, including rabbit articular chondrocytes and human umbilical stem cells.

                  1999.     Comparision of Discography Opening Pressure to T_1ρ Relaxation in the Inter-Vertebral Disc in Vivo

Matthew Fenty¹, Walter RT Witschey 2nd^1,2, Haris Mohammad¹, Philip Maurer³, Ravinder Reddy¹, Dawn Elliott⁴, Arijitt Borthakur¹

¹Radiology, University of Pennsylvania, Philadelphia, Pa, USA; ²Graduate Group in Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, Pa, USA; ³Booth, Bartolozzi, Balderston - 3B Orthopaedics, P.C., Philadelphia, Pa, USA; ⁴McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, Pa, USA

We correlate discography opening pressure with T_1ρ relaxation values within the nucleus pulposus in the inter-vertebral disc. Preliminary data demonstrates an increasing linear trend with opening pressure to mean disc T_1ρ values with an R² of 0.70. Additionally, we find a decreasing linear relationship comparing Pfirrman Grade from T₂ imaging with T_1ρ values with an R² of 0.61 which is similar to previously reported findings.

                  2000.     High Resolution Isotropic DTI of Human Intervertebral Disc Tissue

Alexander C. Wright¹, Steve Pickup², Debra Horng¹, Grace D. O'Connell³, Dawn M. Elliott³

¹Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; ²Small Animal Imaging Facility, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; ³McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA

Within the annulus fibrosus (AF) of the intervertebral disc, collagen fibers play an important role in the distribution of mechanical forces. However, details of their three-dimensional structure have been difficult to measure. Using diffusion tensor imaging (DTI) at high isotropic resolution, we here report DTI measurements on a section of human AF tissue at 90-micron isotropic resolution. Resulting orientations of the principle eigenvector of the diffusion tensors show the expected variation in adjacent lamellae of about +/- 60°. Furthermore, at this voxel size the collagen fibers are directly visible in the diffusion-weighted images.

                  2001.     Quantification of Relaxation Times of Metabolite Resonance in Intervertebral Disc Using MR Spectroscopy

Jin Zuo¹, Xiaojuan Li¹, Sharmila Majumdar¹

¹Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA

Intervertebral disc degeneration related back pain is a leading health problem. Magnetic resonance spectroscopy is a powerful non-invasive tool to assess metabolites in tissues. In planning the data acquisition parameters for using MRS to determine the status of disc degeneration, it is important to consider how to select TR and TE that will emphasize the contrast between metabolites in disc. The optimal TR and TE are determined by T1 and T2. The aim of this study was to evaluate T1 and T2 metabolite relaxation times in intervertebral disc using a single-voxel MRS technique.

                  2002.     MR Spectroscopy in Intervertebral Disc and Correlation with Biochemical Analysis

Jin Zuo¹, Ehsan Saadat¹, Adan Romero², Kimberly Loo³, Thomas Link⁴, Xiaojuan Li¹, Sharmila Majumdar⁵

¹Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA; ²California State Universtiy Monterey Bay; ³Piedmont Hills High School; ⁴Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco , CA, USA; ⁵Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, San Francisco, CA, USA

Intervertebral disc degeneration (IVDD) is a leading cause of lumbar spine-related lower back pain. Clinically, disc degeneration in a patient with lower back pain is diagnosed solely based on morphological techniques. Magnetic Resonance Spectroscopy (MRS) is a non-invasive spectroscopic technique that delivers a biochemical and metabolic representation of the tissue in addition to the anatomic information classically derived from MRI. The goal of this study was to investigate the correlation between biochemical assays of the intervertebral disc of cadaveric spine specimens and bovine specimens with the MRS findings.

                  2003.     ¹H Decoupled ¹³C NMR at 7 Tesla in Humans: Composition of Adipose Tissue

Jimin Ren¹, Ivan Dimitrov², Thomas Cull², James Murdoch², David Foxall², Dean Sherry¹, Craig Malloy¹

¹University of Texas Southwestern Medical Center, Dallas, TX, USA; ²Philips Medical Systems, Cleveland, OH, USA

Broad-band proton decoupled carbon-13 NMR spectra of human adipose tissue were acquired at 7T. The proton decoupling bandwidth was 0.8 - 5.8 ppm. High-quality natural abundance spectra were acquired in about six minutes and the expected resonances from methyl, aliphatic, unsaturated, carbonyl and glycerol carbons were easily identified. The study was well-tolerated by all subjects. The chemical shift dispersion in the “fingerprint” region of the spectrum, 20 - 36 ppm, allowed resolution of specific carbon resonances for trilinolenin and trilinolein. Compared to proton NMR spectra of adipose tissue, natural abundance carbon-13 NMR spectroscopy offers improved chemical specificity for analysis of tissue composition.

                  2004.     Amplification of Achilles Tendon Displacement by a Pivot-Like Restriction Amplifies Final Displacement of Calcaneous and Rotation of Ankle with Possible Impact on Measured Strain.

John Hodgson¹, David Shin¹, Gajanan Nagarsekar¹, V Reggie Edgerton², Shantanu Sinha¹

¹Radiology, University of California at San Diego, San Diego, CA, USA; ²Physiological Sciences, University of California at Los Angeles, Los Angeles, CA, USA

A retinaculum-like restriction on the Achilles tendon has been postulated to modify the mechanics of ankle rotation, possibly amplifying the tendon displacement to a larger displacement of the calcaneous. We have used spin-tag MRI to image the movement of the tendon/aponeurosis and the calcaneous during computer-controlled plantarflexion movements of the foot under passive and active conditions. The lever arm length was determined to be ~53.1 +/- 3.8 mm. Measurements revealed a non-uniform displacement of tendon and aponeurosis along the S/I direction and a potential amplification factor of 1.1. This could have a significant impact of experimentally observed Achilles tendon strain.

                  2005.     Pulmonary Perfusion-Weighted Regional Measurements in Mouse – Primarily Results

Magdalena Zurek¹, Katarzyna Cieslar¹, Monica Sigovan¹, Amine Bessaad¹, Emmanuelle Canet-Soulas¹, Yannick Crémillieux¹

¹Université de Lyon, CREATIS-LRMN, Lyon, France

The combination of radial acquisition with cardiac gating enables high resolution imaging in the rodents lung. We present the results of regional perfusion-weighted measurements based on short echo time radial acquisition. The observed intensity variations in the lung parenchyma were attributed to the changes in blood perfusion depending on the cardiac cycle.

                  2006.     Towards Routine Lung MRI in Small Animals

Sascha Köhler¹, Markus Weiger², Ute Molkentin¹, Franciszek Hennel¹

¹Bruker BioSpin MRI GmbH, Ettlingen, Germany; ²Bruker BioSpin AG, Faellanden, Switzerland

Lung MRI is very demanding because of cardiac and respiratory motion, low proton density, and short T2* values. In the present in-vivo study robust and high quality lung imaging is demonstrated enabling routine studies in small animals. Lung parenchyma in small rodents is visualized with high SNR at 7 T using radial ultrashort TE (UTE) techniques. The 3D and 2D versions of the implemented sequence provide minimum echo times of 20 µs and 400 µs, respectively. Consequently, with 3D UTE hardly any T2* dephasing effects in the lung structure are visible whereas the 2D images show a reduced signal intensity in lung parenchyma, resulting in a higher contrast against the surrounding tissue.

                  2007.     MR Imaging and Quantification of Distal Airway Lung Dysfunction

Elan J. Grossman¹, Ke Zhang¹, Abe Voorhees², Ken I. Berger³, R. M. Goldring³, J. Reibman³, J. Daugherty⁴, J. Xu⁴, Kelly Anne McGorty¹, Qun Chen¹

¹Center for Biomedical Imaging, Department of Radiology, NYU School of Medicine, New York, USA; ²Siemens Medical Solutions, Malvern, PA, USA; ³Department of Medicine, NYU School of Medicine, New York, USA; ⁴Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA

In the current work we present preliminary results of the application of an MR tissue tracking technique for quantitative measurement of spatial distribution and severity of distal airway dysfunction. The goal is to develop a means for early detection of airways disease before any gross changes are observed in standard spirometric variables. In symptomatic patients with distal airway lung dysfunction, topographic mapping of regions with low FEV1/FVC revealed dysfunctional segments were predominately located in the periphery. Distal airway dysfunction as determined by MRI and IOS were tightly linked, confirming presence of distal airway disease that isn’t apparent on standard testing.

                  2008.     Measurement of Regional and Global Lung Ventilation Using Non-Rigid Image Registration

Kelvin Chow¹, Ben Esch², Mark Haykowsky³, Ian Paterson⁴, Richard Thompson¹

¹Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada; ²Cardiovascular Physiology and Rehabilitation Laboratory, University of British Columbia, Vancouver, British Columbia, Canada; ³Physical Therapy, University of Alberta, Edmonton, Alberta, Canada; ⁴Division of Cardiology, University of Alberta, Edmonton, Alberta, Canada

Non-rigid registration of serially acquired MRI lung images provides a direct method for quantifying lung ventilation with minimal user interaction. In-plane deformations are translated into local volume changes, which are combined with respiration rates to measure regional ventilation, and summed over the lungs to determine total lung ventilation. Simultaneous measurement of total ventilation over a large range of ventilation rates (3-35 liters/min) using gold standard spirometry correlated well with MRI rates (R²=0.88). Regional ventilation maps show significant differences (p<0.05) between ventilation in anterior (19±15% volume increase) vs. posterior (30±16%) lung regions, and a continuous chest-to-back gradient in all subjects.

                  2009.     Self-Gated 3D FLASH Imaging of the Human Lung Under Free Breathing Using DC Signals

Stefan Weick¹, Markus Oechsner^1,2, Martin Blaimer³, Felix Breuer³, H Köstler², D Hahn², M Beer², Peter M. Jakob^1,3

¹Experimental Physics 5, University of Würzburg, Würzburg, Germany; ²Institut für Röntgendiagnostik, University of Würzburg, Würzburg, Germany; ³Research Center Magnetic Resonance Bavaria e.V., Würzburg, Germany

In this work, 3D examinations of the human lung were performed during free respiration using the DC signal for self-gating. The DC signal acquisition was implemented into a 3D FLASH sequence and high resolution images were reconstructed retrospectively. The advantages of this method are that neither external measurement devices nor additional RF Pulses for respiratory gating were needed. Threshold values in percent of the total signal difference between expiration and inspiration were defined to select data for image reconstruction. This method is applicable to lung disease patients because it can be performed under free breathing condition.

                  2010.     Gravimetric Validation of Lung Density Measured by Multi-Image Gradient Echo Quantitative MRI

Sebastiaan Holverda¹, Susan Hopkins^1,2, Tatsuya J. Arai¹, G. Kim Prisk^1,2, Rebecca J. Theilmann³

¹Medicine, University of California, San Diego, USA; ²Radiology, University of California, San Diego, USA; ³Radiology, University of California, San Diego, San Diego, CA, USA

A multi-image gradient echo sequence that collects data at two echo times was shown to produce highly reproducible values of lung density in vivo that were found to be consistent with previous studies. It was unknown whether these values represent absolute water content. The goal of this work was to validate our imaging technique against absolute water content measured gravimetrically using excised pig lungs as a model. Imaging results were well correlated and within 9% of actual gravimetric values.

                  2011.     Quantification of Pulmonary Edema in Heart Failure Patients and Controls with B1-Field Corrected Free-Breathing MRI

Kelvin Chow¹, Jessica Scott², Ben Esch², Mark Haykowsky³, Richard Thompson¹, Ian Paterson⁴

¹Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada; ²Cardiovascular Physiology and Rehabilitation Laboratory, University of British Columbia, Vancouver, British Columbia, Canada; ³Physical Therapy, University of Alberta, Edmonton, Alberta, Canada; ⁴Division of Cardiology, University of Alberta, Edmonton, Alberta, Canada

Quantitative pulmonary edema measurements were made in healthy subjects and heart failure patients at 1.5T using a free-breathing HASTE sequence with B₁-field correction. Spatial distribution of the B₁-field was found to have a significant effect on water density measurements (10% underestimation within the left lung), with an average corrected lung water density of 23±2% in healthy subjects and 16% to 37% in heart failure patients. In patients, MRI-derived lung water correlated well with invasively measured left ventricular end-diastolic pressure (R²=0.77) (elevated LVEDP is the primary cause of cardiogenic pulmonary edema) and blood serum b-type natriuretic peptide (BNP) (R² = 0.75).

                  2012.     1.5T Vs. 3.0T: Nodule Detection and Semi-Quantitative Assessment of Pulmonary Nodule

Keiko Matsumoto¹, Yoshiharu Ohno², Hisanobu Koyama², Munenobu Nogami², Daisuke Takenaka², Yumiko Onishi², Nobukazu Aoyama³, Hideaki Kawamitsu³, Kazuro Sugimura²

¹Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan; ²Department of Radiology, Kobe University Graduate School of Medicine; ³Division of Radiology, Kobe University Hospital

Pulmonary MR imaging is adapted for nodule characterization on 1.5T systems in routine clinical practice. Recently, 3.0T MR system is utilized for various MR examinations because of better S/N ratio and higher spatial resolution than 1.5T system. However, there are no reports that 3T system can adapt as substitution to 1.5T system for nodule detection and characterization on chest MR examinations. We hypothesized that 3T MR system have potential for nodule detection and semi-quantitative characterization of pulmonary nodule without significant difference with 1.5T system.

                  2013.     STIR Turbo SE Imaging Vs. Diffusion-Weighted Imaging: Diagnostic Capability for Quantitatively Assessed N-Stage in Non-Small Cell Lung Cancer Patients

Daisuke Takenaka¹, Yoshiharu Ohno¹, Yumiko Onishi¹, Hisanobu Koyama¹, Munenobu Nogami^1,2, Keiko Matsumoto¹, No Aoyama³, H Kawamitsu³, Kazuro Sugimura¹

¹Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan; ²Institute of Biomedical Research and Innovation, Kobe, Hyogo, Japan; ³Division of Radiology, Kobe University Hospital, Kobe, Hyogo, Japan

Assessment of N-stage is very important for management in non-small cell lung cancer (NSCLC) patients. Recently, STIR turbo spin-echo (SE) imaging is suggested as useful for N-stage assessment in NSCLC patients. On the other hand, diffusion-weighted image (DWI) has been suggested as useful for determination of nodal and distant metastases in oncology patients. However, no direct comparison of capability for N-stage assessment has been made between these two methods in NSCLC patients. The purpose of this study was to directly compare diagnostic capability of lymph node metastases between STIR turbo SE imaging and DWI in NSCLC patients.

                  2014.     Diffusion-Weighted Imaging of the Lung Cancers: Preliminary Evaluation of Capability for Detection and Subtype Classification in Pulmonary Adenocarcinomas on Comparison with STIR Turbo SE Imaging

Hisanobu Koyama¹, Yoshiharu Ohno², Nobukazu Aoyama³, Keiko Matsumoto², Yumiko Onishi², Munenobu Nogami⁴, Daisuke Takenaka², Kazuro Sugimura²

¹Radiology, Hyogo Kaibara Hospital, Tanba, Hyogo, Japan; ²Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan; ³Radiology, Kobe University Hospital, Kobe, Hyogo, Japan; ⁴PET, Institute of Biomedical Research and Innovation, Kobe, Hyogo, Japan

Recently, image quality and diagnostic capability of chest MR imaging have been improving and STIR sequence was reported the utility of detection and diagnosis of lung cancer as well as thin-section MDCT. In addition, it has been suggested that diffusion-weighted imaging (DWI) could be useful for assessment of primary malignancy including lung cancer. We hypothesized that DWI was useful sequence for the detection and the subtype classification of pulmonary adenocarcinomas. The purpose of this study was to compare the capabilities for detection and subtype classification in patients with pulmonary adenocarcinoma between DWI and STIR.

                  2015.     Comparative Analysis of Predictive Capability for Postoperative Lung Function Among Dynamic Contrast-Enhanced MRI, CT and Nuclear Medicine Study in Non-Small Cell Lung Cancer Patients

Keiko Matsumoto¹, Yoshiharu Ohno¹, Hisanobu Koyama¹, Munenobu Nogami², Daisuke Takenaka¹, Yumiko Onishi¹, Nobukazu Aoyama³, Hideaki Kawamitsu³, Kazuro Sugimura¹

¹Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan; ²Division of Image-Based Medicine, Institute of Biomedical Research and Innovation, Kobe, Hyogo, Japan; ³Division of Radiology, Kobe University Hospital, Kobe, Hyogo, Japan

The purpose of this study was to compare predictive capabilities for postoperative lung function in non-small cell lung cancer (NSCLC) patients of the state-of-the-art radiological methods including perfusion MRI, quantitative CT and SPECT/CT with that of traditional method such as anatomical method (i.e. qualitative CT) and perfusion scan with SPECT. Correlation coefficient and the limits of agreement between predicted and actual postoperative lung function of perfusion MRI, quantitative CT and co-registered SPECT/CT were better than those of traditional methods. In conclusion, state-of-the-art radiological methods can predict postoperative lung function more accurately than traditional methods in NSCLC patients.

                  2016.     Compartmental Model Analysis of Oxygen-Enhanced MRI and DCE-MRI Detects Pre-Morbid Lung Damage in Smokers

Deirdre Maria McGrath¹, Josephine H. Naish¹, Simon S. Young², Lars E. Olsson³, Charles E. Hutchinson¹, Jorgen Vestbo^4,5, John C. Waterton^1,6, Chris J. Taylor¹, Geoff JM Parker¹

¹Imaging Science and Biomedical Engineering, School of Cancer and Imaging Sciences, University of Manchester, Manchester, UK; ²AstraZeneca, Loughborough, UK; ³AstraZeneca, Mölndal, Sweden; ⁴School of Translational Medicine, Respiratory Research Group, University of Manchester, Manchester, UK; ⁵Department of Cardiology & Respiratory Medicine, Hvidovre University Hospital, Hvidovre, Denmark; ⁶AstraZeneca, Macclesfield, UK

A novel compartmental model analysis of oxygen enhanced MRI (OE-MRI) is proven more sensitive to the presence of early stage chronic obstructive pulmonary disease (COPD) in smokers than spirometry and the OE-MRI parameters used by previous workers. Our model provides biomarkers of ventilation, diffusion of oxygen at the alveoli, and alveolar capillary perfusion and we compare these with biomarkers obtained from dynamic contrast enhanced MRI data. These biomarkers identified the effects of smoking in a group of apparently disease-free smokers as compared with non-smokers, and have therefore the potential to improve the understanding, diagnosis and monitoring of respiratory deficits.

                  2017.     Measurement of Arterial Plasma Oxygenation in Dynamic Oxygen-Enhanced MRI

Lucy Elizabeth Kershaw¹, Josephine Helen Naish¹, Deirdre M. McGrath², John C. Waterton³, Geoffrey James Parker¹

¹Imaging Science and Biomedical Engineering, School of Cancer and Imaging Sciences, University of Manchester, Manchester, UK; ²Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario, Canada; ³Translational Sciences, AstraZeneca, Macclesfield, UK

There has been increasing interest in the use of oxygen as a T₁ contrast agent in MRI. In this work, 7 smokers and 7 never-smokers underwent dynamic oxygen-enhanced imaging, breathing medical air, then 100% oxygen, then medical air whilst T₁ was measured continuously. T₁ values were converted to changes in partial pressure of oxygen dissolved in plasma (DPO₂). The mean plateau DPO₂ value was 350 ± 90 mmHg for smokers and 430 ± 40 mmHg for never-smokers (p=0.049), in agreement with literature values. These noninvasive measurements of DPO₂ have potential in modelling of tissue oxygen uptake and gas exchange in the lungs.

                  2018.     Analysis of Signal Dynamics in Oxygen-Enhanced MRI

Olaf Dietrich¹, Michael Ingrisch¹, Ulrike Attenberger, Michael Peller¹, Konstantin Nikolaou, Maximilian F. Reiser

¹Josef Lissner Laboratory for Biomedical Imaging, Department of Clinical Radiology, LMU Ludwig Maximilian University of Munich, Munich, Germany

In oxygen-enhanced MRI, a block paradigm is frequently used consisting of a series of T₁-weighted scans acquired during alternating inhalation of room air and oxygen. This design results in a signal-time course for each pixel with information about lung function, respiration, and circulation. In this study, the properties of this signal-time course are studied in detail by comparing several model functions with different parameters. The optimal model function is a piecewise exponential function with different time constants for wash-in and wash-out. As a new parameter, it contains the delay between switching the gas supply and onset of the signal change.

                  2019.     Dynamic Oxygen-Enhanced Lung MRI: Cross-Correlation Analysis and Oxygen-Activated Pixels

Olaf Dietrich¹, Ulrike Attenberger, Konstantin Nikolaou, Michael Peller¹, Maximilian F. Reiser

¹Josef Lissner Laboratory for Biomedical Imaging, Department of Clinical Radiology, LMU Ludwig Maximilian University of Munich, Munich, Germany

In oxygen-enhanced MRI, a block paradigm is frequently used consisting of a series of T₁-weighted scans acquired during alternating inhalation of room air and oxygen resulting in a characteristic signal-time course for each pixel. In previous studies, this time course was evaluated by calculating the cross-correlation coefficient of each pixel response function and the ideal box-car waveform. In this study, the cross-correlation is analyzed in O2-MRI with continuous scanning, i.e. including the dynamic signal change during oxygen wash-in and wash-out. It is shown that correlation coefficients are significantly higher if a (shifted) exponential reference function is used for correlation analysis.

                  2020.     Early Detection of Pneumonia by ¹⁹F MRI

Ulrich Flögel¹, Bernd Ebner, Patrick Behm, Jürgen Schrader

¹Institut für Herz- und Kreislaufphysiologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, NRW, Germany

This study was aimed at developing a new approach for the early in vivo detection of inflammation associated with LPS-induced pneumonia in mice. As contrast agent emulsified perfluorocarbons (PFCs) were used, which are biochemically inert and are known to be phagocytized by monocytes/macrophages. The results show that intravenously applied PFCs accumulate in inflamed areas of the mouse lung und can be sensitively detected by ¹H/¹⁹F MRI at a field strength of 9.4 T. Due to the lack of any ¹⁹F background, the observed signals exhibit a high degree of specificity for areas affected by inflammation.

                  2021.     Oxygen-Enhanced MR Imaging: Compared Efficacy of Pulmonary Functional Loss Assessment and Clinical Stage Classification in Asthmatics with Quantitatively Assessed CT

Yoshiharu Ohno¹, Hisanobu Koyama¹, Keiko Matsumoto^1,2, Yumiko Onishi¹, Daisuke Takenaka¹, Munenobu Nogami^1,3, Nobukazu Aoyama⁴, Hideaki Kawamitsu⁴, Kazuro Sugimura¹

¹Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan; ²Radiology, Yamanashi University, Shimokatou, Yamanashi, Japan; ³Division of Image-Based Medicine, Institute of Biomedical Research and Innovation, Kobe, Hyogo, Japan; ⁴Division of Radiology, Kobe University Hospital, Kobe, Hyogo, Japan

Oxygen (O2) -enhanced MRI as well as hyperpolarized noble gas MR imaging have been proposed as useful procedures for evaluation of morphological changes or regional pulmonary functional changes. However, the literature shows no publications dealing with prospective and direct comparison of the capability of quantitatively assessed CT and of O2-enhanced MRI for pulmonary functional loss assessment and clinical stage classification in asthmatics. The purpose of the study reported here was to prospectively and directly compare the efficacy of O2-enhanced MRI and quantitative CT for functional loss assessment and clinical stage classification in asthmatics.

                  2022.     Withdrawn

                  2023.     Determination of the Safety of Gadobenate Dimeglumine in Pediatric Subjects Referred for Routine Contrast-Enhanced MR Imaging Procedures

Guenther Schneider¹, Hellmut Schuerholz², Peter Fries², Miles Andrew Kirchin³, Marcus Katoh², Arno Buecker²

¹Dept. of Diagnostic and Interventional Radiology, University Hospital of Saarland, Homburg / Saar, Germany; ²University Hospital of Saarland, Germany; ³Bracco Imaging SpA, Milan, Italy

A total of 201 pediatric subjects (age range: 0 years – 15 years) underwent CE MRI with gadobenate dimeglumine (Gd-BOPTA, MultiHance) as part of clinical routine . Depending on the specific indication patients received a dose of either 0.05 mmol/kg bodyweight (liver, abdominal imaging, musculo-skeletal imaging, brain and other rare indications) or 0.1 mmol/kg bodyweight (cardio-vascular imaging, MR-urography) Gd-BOPTA (MultiHance). Determination of the safety of gadobenate dimeglumine was made by age-group, clinical indication and dose administered. Based on the results of our retrospective analysis, Gd-BOPTA is a save and efficient contrast agent for imaging of pediatric patients. Both in CE-MRA with a dose of 0.1 mmol/kg BW and in abdominal and muscloskeletal imaging at a dose of 0.05 mmol/kg BW no severe adverse events were noted in a total of 201 patients and 316 studies.

                  2024.     Effect of Intravenous Iron on Nephrogenic Systemic Fibrosis in Rats

Thomas A. Hope¹, Bundit Chaopathomkul¹, Philip E. LeBoit², Whitney A. High³, Victor S. Rogut¹, Robert J. Herfkens⁴, Robert C. Brasch¹

¹Department of Radiology, University of California San Francisco, San Francisco, CA, USA; ²Department of Pathology, University of California San Francisco, San Francisco, CA, USA; ³Department of Dermatology, University of Colorado, Denver, CO, USA; ⁴Department of Radiology, Stanford University, Stanford, CA, USA

Nephrogenic Systemic Fibrosis (NSF) is a debilitating disease associated with the administration of gadolinium-based contrast agents (GBCAs) in patients who have severe renal disease. The administration of intravenous (IV) iron has been implicated as increasing patient specific risk for developing NSF. This study intends to determine if IV iron worsens skin findings in rats that have been administered high dose GBCAs. 12 healthy rats were injected with high dose gadodiamide for 20 days, 6 of which were also injected with IV iron for 10 days. Visual skin inspection and analysis of deposited gadolinium using ICP-AES did not show differences between the two groups, but biopsy analysis, including CD34 staining is still pending.

                  2025.     Evaluation of Toxicity of Gadolinium Based Contrast Agents on Skin Fibroblasts

Rongzuo Xu¹, Xue-Ming Wu¹, Eun-Kee Jeong², Zheng-Rong Lu¹

¹Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, UT, USA; ²Department of Radiology, University of Utah, Salt Lake City, UT, USA

Gadolinium based contrast agents have been reported to induce nephrogenic systemic fibrosis (NSF) in patients with impaired renal function. In this study, we investigated the cytotoxicty of Gd(III)-based contrast agents, including Omniscan®, Mutihance® and ProHance®, to normal rat skin fibroblasts. We find that the gadolinium based contrast agents significantly decreased the cytotoxicity of Gd3+ ions to skin fibroblasts. The intracellular gadolinium deposit depended on contrast agent concentration. Those contrast agents also induce increasing of Ca2+ and decreasing of Zn2+ in intracellular compartments. The Gd3+ deposition and Ca2+ and Zn2+ imbalance could be related to long-term toxicity of gadolinium based contrast agents on skin fibroblast.

                  2026.     Longitudinal Intrarenal Oxygenation Estimated by BOLD MRI in a Murine Model of Renal Ischemia Reperfusion Injury

Eva E. de Vries^1,2, Marlies Oostendorp^1,3, Maarten G. Snoeijs^1,2, L. W.E. van Heurn^1,2, Walter H. Backes^1,3

¹Maastricht University Medical Centre, Maastricht, Netherlands; ²NUTRIM, Maastricht, Netherlands; ³CARIM, Maastricht, Netherlands

Blood oxygenation level dependent (BOLD) MRI can reflect changes in intrarenal oxygenation. In a mouse model of renal ischemia-reperfusion injury, the left renal pedicle was clamped for 45 minutes whereas the right kidney served as internal control. BOLD measurements were performed during baseline, ischemia and at different time points until 24 hours after reperfusion. We demonstrated that the outer medulla of the injured kidney is still more hypoxic than that of the control kidney after 24 hours of reperfusion. This may cause ongoing injury to the outer medulla, even after reperfusion.

                  2027.     Blood-Oxygen Level Dependent (BOLD) Imaging in Native and Transplanted Kidneys on 1.5T and 3.0T

Garima Agrawal¹, Sean B. Fain^1,2, Nathan Artz², Andrew L. Wentland², Thomas M. Grist^1,2, Arjang Djamali³, Elizabeth A. Sadowski¹

¹Radiology, University of Wisconsin, Madison, Madison, WI, USA; ²Medical Physics, University of Wisconsin, Madison, Madison, WI, USA; ³Nephrology, University of Wisconsin, Madison, Madison, WI, USA

We evaluated the reproducibility and feasibility of MR blood-oxygen level dependent (BOLD) measurements in kidneys on 1.5T as well as 3.0T in native and transplanted kidneys. Coefficient of variation (CV) for cortical and medullary R2* values were obtained from both 1.5T and 3.0T within and between subjects. BOLD MR imaging at 3.0T had a comparable reproducibility to 1.5T for normal native kidneys. In transplanted kidneys, BOLD processing at 3T could not be performed in a significant number of subjects due to a significant amount of susceptibility and motion artifacts.

                  2028.     Measurements of Renal Perfusion and Oxygenation in Swine: Preliminary Results

Andrew L. Wentland^1,2, Nathan Artz¹, Arjang Djamali³, Thomas M. Grist², Garima Agrawal², Sean B. Fain^1,2, Elizabeth A. Sadowski²

¹Medical Physics, University of Wisconsin School of Medicine & Public Health, Madison, WI, USA; ²Radiology, University of Wisconsin School of Medicine & Public Health, Madison, WI, USA; ³Nephrology, University of Wisconsin School of Medicine & Public Health, Madison, WI, USA

Non-contrast methods of assessing renal function are important to investigate, given the recent link between nephrogenic systemic fibrosis and gadolinium based contrast agents. Perfusion using non-contrast ASL methods and oxygen bioavailability measurements using BOLD MRI were obtained during states of pharmacologically and physiologically induced increases and decreases in renal perfusion in swine. Heart rate, blood pressure, and urine output were simultaneously monitored during the experiment. Preliminary results with ASL perfusion and BOLD oxygenation measurements show expected changes in each state of increased or decreased perfusion, with corresponding alterations in blood pressure and urine output.

                  2029.     Reproducibility of Diffusion Weighted Imaging at 1.5T and 3T Over a Range of EGFR in Native and Transplant Kidneys

Robert W. Garrett¹, Garima Agrawal¹, Karl Vigen², Sean Fain², Thomas Grist¹, Elizabeth A. Sadowski¹

¹Department of Radiology, University of Wisconsin, Madison, WI, USA; ²Department of Medical Physics, University of Wisconsin, Madison, WI, USA

The purpose of our study is to establish reproducibility of ADC measurements in normal and diminished function native and transplant kidneys at 1.5T and 3T. ADC value variability was low in all four groups at 1.5T and 3T, with all mean coefficient of variation measurements at or below 5% per group. While challenges such as bulk motion and susceptibility artifact must still be overcome, particularly at 3T, our data indicate that DWI is reproducible at both 1.5T and 3T over a range of eGFR in both native and transplant kidneys.

                  2030.     Magnetic Resonance Imaging of Body Calcification In Vitro and In Vivo Using Ultra Short Echo Time (UTE) Sequence

Aya Yassin¹, Ananth J. Madhuranthakam², Ivan Pedrosa¹, B. Nicolas Bloch¹, Atsushi Takahashi³, Neil M. Rofsky¹, Robert E. Lenkinski¹

¹Radiology, Beth Israel Deaconess Medical Center, Boston, MA, USA; ²Applied Science Laboratory, GE Healthcare, Boston, MA, USA; ³Applied Science Laboratory, GE Healthcare, Menlo Park, CA, USA

Measurement of T1 and T2 of calcium oxalate and hydroxyapatite in vitro was performed using an ultra short echo time (UTE) sequence. The resultant measurements were used as a guide for imaging renal stones in vivo in one patient. An MR imaging protocol relied upon gradient echo images obtained with an ultra-short echo time (TE=0.1msec) and a later echo (TE=6.7msec), from which a difference image was obtained. A kidney stone of high signal intensity was clearly visualized and matched the stone seen on an unenhanced CT examination. This provides the basis for future detailed studies of MRI in renal stones.

                  2031.     Detection of Carcinoma in Situ of the Upper Urinary Tract on Dynamic-Enhanced MRI: Superficial Enhancement in Early-Enhanced Phase Images

Masahiro Jinzaki¹, Eiji Kikuchi², Akihiro Tanimoto¹, Shigeo Okuda¹, Hiroaki Sugiura¹, Kozo Sato¹, Sachio Kuribayashi¹

¹Department of Diagnostic Radiology, Keio Univeristy School of Medicine, Tokyo, Japan; ²Department of urology, Keio Univeristy School of Medicine, Tokyo, Japan

The purpose of our study is to prospectively evaluate whether superficial enhancement of dynamic-enhanced MR is useful for the detection of CIS in the upper urinary tract. Dynamic-enhanced MR was performed on seven patients with positive urine cytology but no abnormal findings on cystoscopy and US. Superficial enhancement in early enhanced phase image was seen in six of seven patients, which were pathologically diagnosed as CIS in four and as chronic inflammation in two. Superficial enhancement of dynamic-enhanced MR shows promise in detecting and localizing CIS of the upper urinary tract, which to date, has been unable to be evaluated.

                  2032.     Assessment of Renal Function and Morphology in Potential Living Kidney Donors Using Dynamic Contrast-Enhanced MRI: Initial Results

Cristina Rossi¹, Andreas Boss, Ferruh Artunc², Serdar Yildiz², Petros Martirosian¹, Helmut Dittmann³, Niels Heyne², Claus D. Claussen, Fritz Schick¹, Heinz-Peter Schlemmer

¹Section of Experimental Radiology, Department of Diagnostic and Interventional Radiology, Eberhard Karls University, Tuebingen, Germany; ²Department of Internal Medicine, Eberhard Karls University, Tuebingen, Germany; ³Department of Nuclear Medicine, Eberhard Karls University, Tuebingen, Germany

In this study, the use of a single stop MR examination for the comprehensive evaluation of renal anatomy, (global and split) function, and vessel morphology in candidates for kidney transplantation is proposed. MR-Nephrography was based on the renal clearance of 4ml of gadobutrol from the extra cellular fluid volume. Signal vs. time curves measured over the liver were used for the evaluation of the glomerular filtration rate, whereas curves measured over the kidneys allowed for the assessment of the split renal function. The present protocol may find immediate application in the preoperative assessment of potential living kidney donors.

                  2033.     DCE-MRI Reveals Functional Changes in Murine Kidneys After Warm Ischemia-Reperfusion Injury

Marlies Oostendorp^1,2, Eva E. de Vries^1,3, L. W.E. van Heurn^1,3, Walter H. Backes^1,2

¹Maastricht University Medical Centre, Maastricht, Netherlands; ²CARIM, Maastricht, Netherlands; ³NUTRIM, Maastricht, Netherlands

A common problem of kidney transplantation is that kidneys are damaged due to a period of ischemia between death of the donor and kidney cooling. Novel therapies are being developed to limit renal ischemia-reperfusion injury and improve the clinical outcome of kidney transplants. However, to fully assess their therapeutic efficacy, new non-invasive imaging methods are required. Here, we describe the application of Dynamic Contrast Enhanced MRI using the separable compartment model in combination with a reference region input function, to assess kidney function in a mouse model of renal ischemia-reperfusion injury.

                  2034.     Renal Perfusion and Single-Kidney GFR at 3.0 T Using a 3-Compartment Filtration Model with Reabsorption Correction

David L. Buckley¹, Kola O. Babalola¹, Constantina Chrysochou², Lucy E. Kershaw¹, Ching M. Cheung², Timothy F. Cootes¹, Philip A. Kalra²

¹Imaging Science & Biomedical Engineering, University of Manchester, Manchester, UK; ²Renal Medicine, Salford Royal NHS Foundation Trust, Salford, UK

                  2035.     Multi-Slice Kidney Perfusion Using SE-EPI FAIR: Optimised Acquisition and Analysis Strategies

Alexander Graeme Gardener¹, Susan Tracy Francis¹

¹Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK

Spin-Echo EPI FAIR ASL with parallel imaging acquisition is used to acquire multi-slice perfusion maps of the kidney in less than 3 minutes. The effects of differing breathing strategies (free, respiratory-triggered and breath-hold) are studied and the use of background suppression investigated. The feasibility of image realignment to correct respiratory motion is assessed. It is shown that free breathing and subsequent image realignment provides optimal CNR as well as the paramount strategy for patient comfort. Background suppression is shown to reduced CNR and underestimate perfusion, whilst respiratory triggered acquisition leads to edge effects which cannot be corrected with realignment methods.

                  2036.     Renal Perfusion Imaging Using Continuous Arterial Spin Labeling with Separate Labeling and Imaging Coils

Adam M. Winchell^1,2, Ruitian Song¹, J Pfeuffer³, Ralf B. Loeffler¹, Claudia M. Hillenbrand¹

¹Radiological Sciences, St. Jude Children's Research Hospital, Memphis, TN, USA; ²Biomedical Engineering, University of Memphis, Memphis, TN, USA; ³Siemens Medical Solutions, Malvern, PA, USA

Assessment of renal perfusion rates can provide important information about the physiologic kidney function. Continuous ASL (CASL) using separate RF coils for labeling and imaging have been established as a simple technique to measure blood perfusion in the brain. Here we demonstrate the use of an extra labeling coil for CASL to assess renal perfusion imaging. This approach offers the additional benefit because of it compatibility to other renal perfusion techniques.

                  2037.     Simultaneous Renal Angiography and Quantitative Perfusion Measurement from a Single Time Resolved MRA Data Set

Vikas Gulani¹, Katherine L. Wright², Yu-Hua Fang², Stephen R. Yutzy², Jeffrey L. Duerk^1,2, Mark A. Griswold^1,2, Raymond F. Muzic^1,2

¹Department of Radiology, Case Western Reserve University/University Hospitals of Cleveland, Cleveland, OH, USA; ²Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA

Free breathing, time resolved contrast enhanced MR angiography of the renal vessels was performed with time resolved imaging with stochastic trajectories (TWIST). A kinetic model of perfusion was developed and used to fit ROI data from the renal cortex and medulla. The fit model parameters were used to calculate perfusion in these regions. Half of the standard dose of Gadolinium-DTPA was used (0.05 mmol/kg). This work shows that a single, time resolved angiography data with very low dose Gadolinium can be used to obtain both MRA and perfusion measurements.

                  2038.     Non-Contrast Arterial Spin Labeling Approach to Kidney Perfusion: Assessing Reproducibility in Native and Transplanted Kidneys

Nathan Artz¹, Elizabeth Sadowski², Andrew Wentland¹, Zhifei Wen¹, Garima Agrawal², Thomas Grist^1,2, Arjang Djamali³, Sean Fain^1,2

¹Medical Physics, University of Wisconsin, Madison, WI, USA; ²Radiology, University of Wisconsin, Madison, WI, USA; ³Nephrology, University of Wisconsin, Madison, WI, USA

An ASL-FAIR approach was used to measure kidney perfusion in the cortex of 14 native kidneys and 10 transplanted kidneys in subjects with a range of kidney function. Exams were repeated within each visit and on two separate days and evaluated for reproducibility. The average within day variations was 6 % and the average between day variations was 10 % for the native kidneys and 18 % for the transplanted kidneys.

                  2039.     True-SEEPAGE: A Tool for Evaluating Renal Perfusion and Function

Karan Dara^1,2, Jamal J. Derakhshan^1,2, Andre Fischer³, Stephen R. Yutzy^1,2, Nicole Seiberlich², Jeffrey L. Duerk^1,2, Mark A. Griswold^1,2, Vikas Gulani^1,2

¹Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA; ²Radiology, University Hospitals of Cleveland and Case Western Reserve University, Cleveland, OH, USA; ³Physikalisches Institut, University of Wurzburg, Germany

True-SEEPAGE is a non-subtraction non-contrast based segmented imaging technique which can be used to study renal perfusion and function while avoiding the problem of Nephrogenic Systemic Fibrosis that may be associated with Gd-based contrast agents. In True-SEEPAGE, the stationary tissue is saturated and the unsaturated spins from inflowing are imaged, giving rise to a true perfusion signal in the kidney. Observed perfusion is seen as a function of renal arterial blood flow. This technique may, in the future, be used to detect and characterize tumors in the kidney without the administration of contrast agents.

                  2040.     Signs of a Tubular Defect Preceding the Impairment of  Glomerular Filtration in Alport Mice as Measured by DCE-MRI

Didier Laurent¹, Farid Sari-Sarraf¹, Peter O'Donnell¹, Jennifer Allport-Anderson¹

¹Novartis Institutes for Biomedical Research, Cambridge, MA, USA

This in vivo study explored the gradual development of kidney dysfunction in the COL4A3-knockout mouse model of Alport syndrome (AS) using DCE-MRI. Unlike global and relatively insensitive markers of kidney function, such as proteinuira, blood urea nitrogen and creatinine, results obtained by DCE-MRI demonstrated the specific defects in glomerular filtration and tubular water reabsorption on a regional basis, as early signs of renal failure. Results of this study can be used for the evaluation of different therapies targeting AS.

                  2041.     Measurement and Comparison of T1 Relaxation Times in Native and Transplanted Kidney Cortex

Yin Huang¹, Nathan Artz¹, Zhifei Wen¹, Elizabeth Sadowski^1,2, Sean Fain^1,2

¹Medical Physics, University of Wisconsin-Madison, Madison, WI, USA; ²Radiology, University of Wisconsin-Madison, Madison, WI, USA

An interactive segmentation method was developed to measure the T1 of renal cortex on a pixel-by-pixel basis. Native (22 kidneys) and transplanted (11 kidneys) kidneys with a wide range of kidney functions were analyzed to determine whether there is a difference between the native and transplant T1 values. The average T1 of cortical tissue in native kidneys is 1002¡À47.4 (mean¡Àstandard deviation) msec and the average T1 of cortical tissue in transplanted kidneys is 1180 ¡À110.6 msec. This difference was found to be statistically significant (p = 0.0022).

                  2042.     Assessment of Kidney Stiffness in a Swine Model of Renal Arterial Stenosis with 7-D MR Elastography

Meng Yin¹, Lizette Warner², Lilach O. Lerman², Armando Manduca¹, Richard L. Ehman¹

¹Department of Radiology, Mayo Clinic, Rochester, MN, USA; ²Division of Nephrology & Hypertension, Mayo Clinic, Rochester, MN, USA

7-D MR Elastography (MRE) acquisition involves obtaining displacement data for 3 dimensions in space, 3 cyclic displacement directions at each point in space, and at multiple time points in the wave cycle. We observed that 7-D MRE provides renal parenchymal stiffness measurements that have similar mean values but a smaller standard deviation than 2-D measurements for the same kidney in a porcine model of acute renal artery stenosis. It is sufficiently sensitive to detect expected reactive stiffness changes in the contralateral kidney in an experimental animal model of RAS. It also provides motivation for further development of 7-D MRE techniques.

                  2043.     In Vivo Localized 1D and 2D MRS of Rat Kidney Using a Clinical 3T MRI/MRS Scanner

S. Sendhil Velan¹, Kevin Engels², Susan Lemieux¹, Raymond R. Raylman¹, Vazhaikkurichi M. Rajendran³

¹Center for Advanced Imaging and Department of Radiology, West Virginia University, Morgantown, WV, USA; ²Department of Physiology, West Virginia University, Morgantown, WV, USA; ³Section of Digestive Diseases, Department of Medicine, West Virginia University, Morgantown, WV, USA

We have implemented advanced MRS techniques to investigate rat kidney. Our preliminary investigation demonstrates the presence of two sets of lipid signals. The intracellular signals may not come from renal cells; they may be from adipose cells or from accumulation of lipids through foam-cell formation. The non-invasive assessment of biochemistry in the kidney should be helpful in understanding physiological responses as well as disease induced adaptation in this complex organ.

                  2044.     Quantitative MRI Markers for Cystic Kidney Disease Progression in an ARPKD Rat Model

Chris A. Flask^1,2, David Johnson², Vikas Gulani¹, Rania Osman^3,4, Nita Hoxha^3,4, Katherine MacRae Dell^3,4
1Radiology, Case Western Reserve University, Cleveland, OH, USA; ²Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA; ³Pediatrics, Case Western Reserve University, Cleveland, OH, USA; ⁴Rammelkamp Center for Education and Research, MetroHealth Medical Center, Cleveland, OH, USA

Autosomal Recessive Polycystic Kidney Disease (ARPKD), overall kidney function diminishes only after significant disease progression. In addition, ARPKD is characterized by both macrocysts and microcysts which are not consistently delineated by conventional diagnostic imaging techniques. Our initial results in the PCK rat model of ARPKD demonstrate that quantitative MRI techniques such as Diffusion Weighted Imaging overcome this obstacle and allow non-invasive monitoring of ARPKD disease progression. We have also developed a quantitative analysis methodology to provide consistent characterization of ARPKD kidneys that can be easily translated to clinical applications.

                 2045.     MRI Assessment of the Water Distribution in the Ascending Colon in Health and a Model of Diarrhoeal Disease

Elisa Placidi¹, C L. Hoad¹, L Marciani², E F. Cox¹, S Pritchard¹, C Costigan³, R C. Spiller², P A. Gowland¹

¹SPMMRC, School of Physics and Astronomy, University of Nottingham, Nottingham, UK; ²Nottingham Digestive Diseases Centre Biomedical Research Unit, University of Nottingham, Nottingham, UK; ³Brain and Body Centre, University of Nottingham, Nottingham, UK

MRI was used to investigate and quantify the changes in colonic and small bowel water content following a mannitol drink, a laxative known to induce small bowel secretions. Five healthy volunteers were imaged on a 1.5 T Philips Achieva scanner with several sequences to assess changes in water content in the ascending colon in terms of water volume, T2, and image signal intensity. Increases in water content in the bowel from the mannitol drink resulted in more homogeneous signal intensity in the colon compared to the undisturbed state, with T2s higher than those measured in the colon after just water.

                  2046.     In Vivo Detection of Colitis and Colitis-Associated Early Colorectal Tumors in Mice Using Dynamic Contrast-Enhanced Magnetic Resonance Imaging

Devkumar Mustafi¹, Urszula Dougherty², Marc Bissonnette², Xiaobing Fan³, Gregory S. Karczmar³, Erica Markiewicz³, Marta Zamora³

¹Biochemistry  & Molecular Biology, The University of Chicago, Chicago, IL, USA; ²Medicine, The University of Chicago, Chicago, IL, USA; ³Radiology, The University of Chicago, Chicago, IL, USA

We have developed a high-resolution in vivo MRI method to assess the state of colitis and to facilitate the early detection of colitis-associated colorectal tumors in mice. Using both high-resolution T1/T2-weighted MR images and dynamic Gd-DTPA contrast-enhanced MRI studies of control, colitis, colorectal tumor, and colitis-to-early colorectal tumor-bearing mice, we have demonstrated that early colorectal tumors can be detected and that the neoplastic transformation stage of chronic colitis can be distinguished from early colitis-associated cancers. In vitro 2-D histological studies were also performed for characterizing colitis and monitoring its progression from colitis to cancer in a clinically relevant model.

                  2047.     Prospective Comparison of Dark Lumen MR Colonography with Conventional Colonoscopy in Asian Population: Preliminary Results

Sudhakar Kundapur Venkatesh¹, Wai Kit Cheong², Bertrand WL Ang³, Lawrence Ho⁴, Christopher Khor⁵

¹Diagnostic Imaging , National University Health System, Singapore , Singapore; ²Surgery, National University Health System, Singapore, Singapore; ³Diagnostic Imaging, National University Health System, Singapore, Singapore; ⁴Medicine, National University Health System, Singapore; ⁵Medicine, National University Health System, Singapore, Singapore

MR Colonography has been demonstrated to be a promising modality for detection of clinically significant polyps in the Western population. To the best of our knowledge there are no studies in Asian population. We performed a prospective comparison study of MR Colonography with conventional colonoscopy. The results of our study show that MR Colonography is feasible and has 94% accuracy for detection of clinically significant polyps similar to that reported in literature.

                  2048.     The Use of SPAMM for the Assessment of Motility Patterns in the Small Bowel

Andre M.J. Sprengers¹, Frank Zijta¹, Aart J. Nederveen¹, Frits J. de Bruijn², Rolf M. Lamerichs², Jaap Stoker¹

¹Radiology, Academic Medical Centre, Amsterdam, Noord Holland, Netherlands; ²Philips Research, Eindhoven, Netherlands

SPAMM or SPAtial Modulation of the Magnetization is a well known prepulse tagging

                  2049.     Accuracy of MR Enterography Compared to CT Enterography in Young Patients with Bowel Disease.

Marianne Michal Amitai¹, lisa Raviv -Zilka¹, Tammar Kushnir¹, Sara Apter¹

¹Dept. of Diagnostic Imaging, Sheba Medical Center, Tel Hashomer, Israel

The high radiation exposure in CT Enterography (CTE) is a growing concern in imaging. The improvement in bowel MR opens the possibility of using this modality. The purpose was to compare the diagnostic accuracy of MR-Enterography (MRE) to CTE. Mural and extra mural radiological features were evaluated. Thirty six patients had MRE and CTE within 6 months. MRE correlated well with CTE having similar accuracies: 100%, 91%, 89%, 72%, and 65% for abscess, bowel wall thickening, phlegmon, luminal narrowing, and fistula, respectively. Therefore MRE should be recommended in young and pregnant patients in whom radiation exposure is particularly hazardous.

                  2050.     High  Contrast to Noise Ratio (CNR) Using CO2 for Colonic Distension in 3.0 Tesla Magnetic Resonance Colonography (MRC)

Frank Zijta¹, Aart Nederveen¹, Jaap Stoker¹

¹Radiology, Academic Medical Center, Amsterdam, Noord-Holland, Netherlands

Magnetic Resonance Colonography (MRC) has been increasingly evaluated as a screening technique in de detection of colorectal carcinoma (CRC). In this study we evaluated the feasibility of MRC using CO2 as intraluminal contrast medium. MRC quality is assessed by calculating the contrast to noise ratio (CNR) between colonic lumen and colonic wall. Data was acquired using T1 weighted TFE and T2 weighted HASTE sequences on a 3.0 Tesla unit. We found high CNR for all colonic segments.

                  2051.     Carcinoid Tumors of the Small Bowel: Characteristic Imaging Features in MR-Enteroclysis

Christine Schmid-Tannwald¹, Maximilian Ferdinand Reiser², Christoph Johannes Zech², Karin Anna  Herrmann²

¹ludwig-Maximilians-University, Munich, institute of clinical Radiology, munich, bavaria, Germany; ²Ludwig-Maximilians-University, Munich, Institute of clinical Radiology, Munich, Bavaria, Germany

MRE is a valuable tool in the detection and localization of primary carcinoid tumors, appropriate bowel distension provided. A number of characteristic morphologic imaging features can be established at MRE to characterize primary carcinoid tumors and their loco-regional metastases.

                  2052.     Quantitative Analysis of Peristaltic and Segmental Motilities in the Rat GI Tract with Dynamic MRI and Spatio-Temporal Maps

Amit Ailiani¹, Thomas Neuberger², Gino Banco³, James Brasseur³, Nadine Smith¹, Andrew Webb⁴

¹Bioengineering, Penn State University, University Park, PA, USA; ²Huck Institute, Penn State University, USA; ³Mechanical Engineering, Penn State University; ⁴Radiology, Leiden University Medical Center, Leiden, Netherlands

Non-invasive dynamic MRI in the jejunum region of an anesthetized rat has been used to produce spatiotemporal maps representing peristaltic and segmental motions. Frequency analysis of these motions give results which are in good agreement with previous work which has all been performed using highly invasive techniques involving external isolation of the gut. Dynamic MRI provides quantitative information on many physiological parameters such propagation velocity, wavelength, speed of collapse and the period of the motilities. Physiological parameters which are not dependent upon the exact position of the MRI slice were found to be statistically the same between animals (n=6).

                  2053.     MRI Assessment of the Effects of the Physical Form of a Meal on Gastric Emptying, Gallbladder Contraction, Small Bowel Water Content and Satiety

Luca Marciani¹, Nicholas Hall¹, Caroline L. Hoad², Susan E. Pritchard², Eleanor F. Cox², John J. Totman³, Robin C. Spiller¹, Penny A. Gowland²

¹Nottingham Digestive Diseases Centre Biomedical Research Unit, University of Nottingham, Nottingham, UK; ²Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham, UK; ³Brain and Body Centre, University of Nottingham, Nottingham, UK

Manipulating the physical form of food may have an impact on gastrointestinal function and satiety. We hypothesised that feeding to healthy volunteers a solid/liquid meal blended to a soup: (a) gastric volumes would fall more slowly (b) satiety would be enhanced (c) the CCK duodenal response (as inferred from gallbladder contraction) would be enhanced and (d) the small bowel secretion would be greater. We were able to test these hypotheses by carrying out carried one satiety study in quiet controlled conditions and one mechanistic study using serial, functional gastrointestinal MRI.

                  2054.     Preoperative Evaluation of Peritoneal Carcinomatosis Using Multiphasic Dynamic Contrast Enhanced MR-Imaging in Correlation with Complete Surgical Exploration and Histopathology

Bernhard Daniel Klumpp¹, Ingmar Koenigsrainer², Philipp Aschoff¹, Matthias Lichy¹, Claus D. Claussen¹, Alfred Koenigsrainer², Christina Pfannenberg¹, Stephan Miller¹

¹Diagnostic Radiology, Eberhard-Karls University Tuebingen, Tuebingen, Baden-Wuerttemberg, Germany; ²Abdominal surgery, Eberhard-Karls University Tuebingen, Tuebingen, Baden-Wuerttemberg, Germany

In patients with peritoneal carcinomatosis (PC) accurate preoperative assessment of the extent of PC is essential to provide optimal clinical outcome of radical peritonectomy. Purpose was to assess the diagnostic potential of multiphasic dynamic contrast enhanced MRI (T1wDCE) to determine the extent of PC in correlation with surgical and histopathological findings. 15 patients with PC were included. The mean peritoneal cancer index (PCI, Sugarbaker) was 18.1±12.2. The sensitivity/segment was 84%, specifity 91%, negative predictive value 68%, positive predictive value 96%, diagnostic accuracy 86%. T1wDCE provides accurate preoperative assessment of PC regarding resectibility to ensure optimal patient selection for peritonectomy.

                  2055.     Assessment of Bowel Inflammation in Crohn’s Disease by Using Quantitative Dynamic Contrast Enhanced MRI

Aytekin Oto¹, Xiaobing Fan¹, Devkumar Mustafi¹, Gregory S. Karczmar¹, David T. Rubin²

¹Radiology, The University of Chicago, Chicago, IL, USA; ²Medicine, The University of Chicago, Chicago, IL, USA

MRI has recently emerged as a valuable tool in detection of bowel abnormalities and evaluation of Crohn`s disease. To evaluate the feasibility of quantitative analysis of dynamic contrast enhanced MRI (DCE-MRI) in detection of bowel inflammation in patients with Crohn`s disease, we analyzed DCE-MRI data based on a two-compartmental pharmacokinetic model and semi-quantitative parameters derived from an empirical mathematical model. The results demonstrated that inflamed bowel segments had faster transfer rate, larger extravascular extracellular space volume, higher contrast uptake, larger value of initial area under the curve, and steeper enhancement slope than normal bowel.

                  2056.     Assessment of Tumor Microcirculation in Rectum Carcinoma with Regard to Different Pharmacokinetic Models, Intra- Tumor Heterogeneity and Therapeutic Effects After Neoadjuvant Radio-Chemotherapy

Andreas Markus Hoetker¹, Peter Mildenberger¹, Theo Junginger², Christoph Dueber³, Torsten Hansen⁴, Matthias Menig⁵, Andreas Pohlmann, Achim Heintz⁶, Katja Oberholzer³

¹Klinik und Poliklinik für diagnostische und interventionelle Radiologie, Klinikum der  Johannes- Gutenberg Universität Mainz, Mainz, Germany; ²Klinik und Poliklinik für Allgemein- und Abdominalchirurgie, Klinikum der Johannes- Gutenberg Universität Mainz, Mainz, Germany; ³Klinik und Poliklinik für diagnostische und interventionelle Radiologie, Klinikum der Johannes- Gutenberg Universität Mainz, Mainz, Germany; ⁴Institut für Pathologie, Klinikum der Johannes- Gutenberg Universität Mainz, Mainz, Germany; ⁵Klinik und Poliklinik für Radioonkologie sowie Strahlentherapie, Klinikum der Johannes- Gutenberg Universität Mainz, Mainz, Germany; ⁶Klinik für Allgemein-, Viszeral- und minimalinvasive Chirurgie, St. Hildegardis Krankenhaus, Mainz, Germany

To assess the therapeutic effects of neoadjuvant radio-chemotherapy on tumor microcirculation DCE- MRI parameters were measured in patients with rectum carcinoma using two slices in maximal tumor extent per patient and measurement. The results of these different models (Brix/Tofts) were compared between each other and the different slices and showed, that the slice selection did not affect later analysis and that it was not possible to find a relevant difference in therapeutic effects between the corresponding parameters of the pharmacokinetic models.

                  2057.     Dynamic Perfusion Study of Mouse Pancreas with an Intravascular Contrast Agent

Philip Lee¹, Xavier Golay², George K. Radda¹

¹Lab of Molecular Imaging, Singapore Bioimaging Consortium (A-STAR), Singapore, Singapore; ²UCL Institute of Neurology, UK

Dynamic perfusion studies on mice pancreas has been carried out with an intravascular contrast agent that has long lifetime and 6-10 times higher T1-relaxivity than commonly used Gd-DTPA. This eliminates dubious positive enhancement from agent’s diffusion into tissue, while strengthening signal intensity. Time-to-peak is 6mins after a 30ul (1mk/kg) bolus intravenous injection. This indicator of blood flow can be used to compare the different hemodynamic responses in diabetic mice models. Coupled with fast pancreas localization scan, this study paves the way for subsequent quantification work to further understand glucose metabolism.

                  2058.     Intraportal Islet Transplantation Assessed by Dynamic Contrast Enhanced Magnetic Resonance Imaging

Nathaniel Chan¹, Naoaki Sakata¹, Eba Hathout¹, Andre Obenaus²

¹Islet Transplant Laboratory, Department of Pediatrics, Loma Linda University, Loma Linda, CA, USA; ²Radiation Medicine, Loma Linda University, Loma Linda, CA, USA

Successful vascularization plays an important role in long-term viability and function of pancreatic islet grafts after transplantation. Dynamic contrast enhanced (DCE) MRI has been successfully used to assess vascularization in tumors. However, in vivo imaging and determination of intraportal islet-specific hemodynamic parameters has not been studied. The aim of this study was to evaluate the potential of DCE MRI for assessment of vascularization of islet transplantation in the liver. The data show that DCE can provide a non-invasive assessment of angiogenesis following islet transplantation and can provide the basis for future clinical assessments of islet vascularization.