Ludovica Romanin^1,2, Christopher W. Roy², Milan Prsa³, Tobias Rutz⁴, Estelle Tenisch², Matthias Stuber^2,5, and Davide Piccini^1,2
1Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland, ²Department of Diagnostic and Interventional Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland, ³Division of Pediatric Cardiology, Woman-Mother-Child Department, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland, ⁴Service of Cardiology, Heart and Vessel Department, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland, ⁵Center for Biomedical Imaging (CIBM), Lausanne, Switzerland

This work proposes an automated subject-specific individual pixels selection as an alternative to a fixed coil selection for the initialization of the input data to a similarity-driven multi-dimensional binning algorithm (SIMBA) for free-running motion-suppressed whole-heart acquisitions. By selecting timeseries with a high low-frequency energy content, we include only pixels with respiratory and cardiac information. Compared to the original method, this leads to a more accurate choice of end-expiration and diastolic phases for the reconstruction of sharp whole-heart and coronary images. Moving forward, the method needs to be refined, optimized and tested to further improve the image quality. 

Qing FU¹, Jia-wei Wu¹, Jing-yang Li¹, Peng Sun², and Xiang-chuang Kong^1
1Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China, ²Philips Healthcare, Beijing, China

Conventional subtracted whole-body CE-MRA is time-consuming and requires experiences for operators. Instead, one-stop subtractionless CS-MRA in our study could depict the whole-body arterial vasculatures with only once contrast injection and only 0.15 mmol/kg dose, which assisted by multiple techniques including reverse k-space filling mode, total imaging matrix system, automatic table moving, automatic coil selection and especially the CS technique. The comparative results supported it feasible with accepted image qualities and a faster acquisition time in clinical use.

Xi Wu^1,2, Jiayu Sun¹, Xiaoyong Zhang³, and Zhigang Wu^4
1Department of Radiology, West China Hospital of Sichuan University, Chengdu, China, ²North Sichuan Medical College, Nanchong, China, ³Philips Healthcare, Chengdu, China, ⁴Philips Healthcare, Shenzhen, China

Currently, modified dixon (mDixon) gradient echo sequence is widely used for respiratory navigated whole-heart coronary magnetic resonance angiography (MRA) for the evaluation of coronary anatomy and abnormalities. However, the main drawback of this approach is that the scan time is longer and prone to interference with motion artifacts. In this study, we investigated the utility of whole-heart coronaryMRA using accelerated mDixonwith compressed sensing (CS) and artificial intelligence(AI) technologies at 3Tesla. The initial results showedtheCS-AI mDixontechnique has potential to be the most viable alternative to enhance the clinical workflow of coronary MRA.

Anastasia Fotaki¹, Camila Munoz¹, Alina Hua¹, Yaso Emmanuel², Karl Philip Kunze^1,3, Radhouene Neji^1,4, Pier Giorgio Masci¹, René Botnar^1,5, and Claudia Prieto^1,5
11School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, ²Guy's and St Thomas' Hospital, London, United Kingdom, ³MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom, ⁴2MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom, ⁵Escuela de Ingeniería, Pontificia Universidad Católica de Chile, Santiago, Chile

Cardiovascular Magnetic Resonance Angiography is established for serial monitoring of thoracic aortic disease. Limitations of the current approach include the diaphragmatic navigation, leading to long acquisition times and the correction of the aortic motion, solely in one direction. We propose a T2-prep bSSFP sequence that incorporates image-based navigation and inline non-rigid motion-correction for efficient, free-breathing and isotropic aortic imaging. Comparison between the conventional and the research sequence shows similar diagnostic confidence with both techniques in much shorter acquisition time [3.11.1min (iNAV) versus 11.5 min3.4 (dNAV),P<0.0001] and good agreement of aortic measurements between both techniques, holding promise for forthcoming clinical adoption. 

Stephen G Jermy^1,2, Elizabeth M Tunnicliffe³, Ntobeko A B Ntusi^2,4, and Ernesta M Meintjes^1,2
1Division of Biomedical Engineering, Department of Human Biology, University of Cape Town, Cape Town, South Africa, ²Cape Universities Body Imaging Centre (CUBIC), University of Cape Town, Cape Town, South Africa, ³Oxford Centre for Magnetic Resonance Research (OCMR), Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom, ⁴Department of Medicine, University of Cape Town, Cape Town, South Africa

A prospective respiratory motion correction control system, capable of slice-following, was tested on a 3 T clinical MRI scanner. The performance of the control system was compared against the most common respiratory motion compensation technique, namely multiple breath-holds. Both techniques produced similarly consistent results. The control system technique was able to reduce the acquisition time by acquiring data with 100% respiratory efficiency

Johanna Stimm¹, Sebastian Kozerke¹, and Christian Stoeck^1,2
1Institute for Biomedical Engineering, University and ETH Zurich, Zuerich, Switzerland, ²Division of Surgical Research, University Hospital Zurich, University Zurich, Zurich, Switzerland

To address the challenge of low resolution and limited number of slices in in-vivo cDTI, and the need for 3D structural information in image-based modeling, we compare five interpolation techniques of predominant cardiomyocyte orientation: two low-rank models, one rule-based method and two tensor interpolation approaches. The direct tensor interpolation approaches result in the smallest errors, followed by the low-rank models and the rule-based method. In view of an optimal experimental design in-vivo, the ex-vivo experiments suggest a larger benefit of increasing in-plane resolution rather than SNR, and a non-linear increase in error for less than five short-axis slices.

Tyler E Cork^1,2,3, Matthew J Middione^1,2, Michael Loecher^1,2, Congyu Liao¹, Kévin Moulin^4,5, Kawin Setsompop^1,6, and Daniel B Ennis^1,2,7
1Department of Radiology, Stanford University, Stanford, CA, United States, ²Division of Radiology, Veterans Administration Health Care System, Palo Alto, CA, United States, ³Department of Bioengineering, Stanford University, Stanford, CA, United States, ⁴CREATIS Laboratory, University of Lyon, Lyon, France, ⁵Department of Radiology, University Hospital Saint-Etienne, Saint-Etienne, France, ⁶Department of Electrical Engineering, Stanford University, Stanford, CA, United States, ⁷Cardiovascular Institute, Stanford University, Stanford, CA, United States

To maintain minimal scan times, cardiac Diffusion Tensor Imaging (cDTI) uses an echo-planar imaging (EPI) readout. Off-resonance, that causes geometric distortion in EPI, remains an obstacle that degrades image quality and can affect the underlying quantitative information. In cDTI, the lung/liver/heart interface amplifies the effect of geometric distortion. Distortion correction algorithms, such as TOPUP and DR-BUDDI, have proved to adequately correct distortion in neuroimaging, but limited work has been done for the heart. A first look at comparing these two correction strategies head-to-head was evaluated and resulting in TOPUP as a slightly better tool addressing distortion correction in the heart.

Qi Huang^1,2, Jason Mendes¹, Ganesh Adluru¹, and Edward DiBella^1
1Utah Center for Advanced Imaging Research (UCAIR), University of Utah, Salt Lake City, UT, United States, ²Biomedical Engineering, University of Utah, Salt Lake City, UT, United States

Here we study SSFP-based OS-CMR and EPI-based T2*/T2 methods for detection of myocardial oxygenation changes. These techniques have been used previously, and OS-CMR has been investigated in many studies. However, quantifying T2* and T2 every heartbeat may add information to the semi-quantitative OS-CMR method. Here a limited study of subjects on a 3T scanner is performed. Preliminary quantitative results including comparisons between the methods are shown.

Inka Ristow¹, Shuo Zhang², Caroline-Viktoria Hancken³, Maria Stark⁴, Carsten Rickers⁵, Christoph Katemann², Peter Bannas¹, Gerhard Adam¹, Jochen Herrmann³, Lennart Well¹, and Julius Matthias Weinrich^3
1Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, ²Philips GmbH Market DACH, Hamburg, Germany, ³Department of Diagnostic and Interventional Radiology and Nuclear Medicine, Section of Pediatric Radiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, ⁴Institute of Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, ⁵University Heart Center, Adult Congenital Heart Disease Unit, University Medical Center Hamburg-Eppendorf, Hamburg, Germany

High-quality cardiac MRI at 3T in sedated children with congenital heart disease (CHD) is challenging, because of field inhomogeneities and free breathing motions. Therefore, we aimed to employ the non-contrast free-breathing generic T1-weighted turbo-field echo (TFE) sequence with compressed sensing reconstruction for assessment of vessel diameters and evaluation of the intra- and extracardiac structures in children with CHD aged <5 years. Our results show a highly reliable clinical applicability for intra- and extracardiac structures with significantly higher accuracy in comparison to contrast-enhanced MR-angiography and 3D-Dixon sequences.

Shubhajit Paul¹, Raphael Tomi-Tricot^1,2, Karl Philipp Kunze^1,2, Shaihan Malik^1,3, Joseph V. Hajnal^1,3, Philippa Bridgen^1,3, Thomas Wilkinson^1,3, Sharon Giles^1,3, Radhouene Neji^1,2, Reza Razavi¹, Claudia Prieto^1,4, and René Michael Botnar^1,4
1School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom, ²MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom, ³The London Collaborative Ultra high field System (LoCUS), London, United Kingdom, ⁴Escuela de Ingeniería, Pontificia Universidad Católica de Chile, Santiago, Chile

In spite of the promised increase in signal-to-noise ratio and contrast to noise ratio, 3D whole-heart imaging at 7T remains challenging predominantly due to B₁, B₀ inhomogeneity, specific absorption rate limitations and coil-depth issues for single transmit. Here, we developed a toolbox to optimize the adiabatic hyperbolic secant refocusing pulse with respect to B₁ and B₀ inhomogeneity typically used for T₂-preparation in non-contrast 3D Coronary Magnetic Resonance Angiography (CMRA). We present phantom and in vivo data for 3D CMRA employing a low excitation flip-angle scheme.