Joint Annual Meeting ISMRM-ESMRMB 2014 10-16 May 2014 Milan, Italy

TRADITIONAL POSTER SESSION ○ CARDIOVASCULAR

CARDIOVASCULAR (13:30-15:30)

2363-2375 Myocardial Function
2376-2416 Myocardial Perfusion
2417-2463 Myocardial Tissue Characterization
2464-2502 Velocity & Flow Imaging
2503-2521 CE & Non-CE MRA
2522-2552 Vessel Wall Imaging & Emerging Technologies
   

TRADITIONAL POSTER SESSION ○ CARDIOVASCULAR
Myocardial Function

 
Wednesday 14 May 2014
Traditional Poster Hall  13:30 - 15:30

2363.   
Evaluate Myocardial Function for Patient with Marfan Syndrome by Using Phase-Contrast Magnetic Resonance Imaging
Tzu-Yu Chou1, Hsin-Hui Chiu2, Wen-Yih Isaac Tseng3, Marius Menza4, Bernd Jung4, and Hsu-Hsia Peng1
1Department of Biomedical Engineering and Environmental Sciences, Hsinchu, Taiwan, 2Department of Pediatrics, Taipei Medical University Hospital, Taipei, Taiwan,3Center for Optoelectronic Biomedicine, College of Medicine, National Taiwan University, Taipei, Taiwan, 4Medical Physics, Department of Radiology, University Hospital Freiburg, Freiburg, Germany

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

 
2364.   Local Coil versus Conventional Body Coil Transmission for Cardiac MR: B1+ Efficiency Improvements and Enhanced Blood Myocardium Contrast for 2D CINE SSFP Imaging at 3T
Oliver Kraus1, Lukas Winter1, Matthias Dieringer1,2, Andreas Graessl1, Jan Rieger3, Celal Oezerdem1, Fabian Hezel1, Andre Kuehne4,5, Patrick Waxmann6, Harald Pfeiffer6, and Thoralf Niendorf1
1Berlin Ultra-High Field Facility, Max-Delbrueck Center, Berlin, Germany, 2Working Group on Cardiovascular MR, Experimental and Clinical Research Center (ECRC), Berlin, Germany, 3MRI.TOOLS GmbH, Berlin, Germany, 4Center for Medical Physics and Biomedical Enginieering, Medical University of Vienna, Austria, 5MR Center of Excellence, Medical University of Vienna, Austria, 6Medical Physics and Metrological Information Technology, Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany

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

 
2365.   MICROVASCULAR OBSTRUCTION INHIBITS INFARCT HEALING AND ENHANCES COMPENSATORY VENTRICULAR HYPERTROPHY: EXPERIMENTAL CARDIAC MRI STUDY
Maythem Saeed1, Hisham Z. Bajwa1, Loi Do1, Mohammed SA Suhail1,2, Steve W. Hetts1, and Mark W. Wilson1
1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, United States, 2Radiology, University of California, San Diego, San Diego, California, United States

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

 
2366.   Quantification of L-type Calcium Channel Activity by Manganese-Enhanced MRI in Murine Hearts in Vivo
Kai Jiang1,2, Wen Li1,2, Raymond F. Muzic1,3, and Xin Yu1,3
1Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, United States, 2Case Medical Center, Case Western Reserve University, Cleveland, Ohio, United States, 3Department of Radiology, Case Western Reserve University, Cleveland, Ohio, United States

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

 
2367.   Noise reduction in CP-SSFP myocardial BOLD images: deformable image registration and temporal averaging
Syue-Yu Jhang1 and Teng-Yi Huang1
1National Taiwan University of Science and Technology, Taipei, Taiwan

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

 
2368.   Evaluation of Single Breath Hold 3D Cardiac Cine MRI using kat-ARC In Patients and Healthy Volunteers on 1.5T
Daniel Jeong1, Peng Lai2, Karl K. Vigen1, Kang Wang3, James H. Holmes3, Kevin M. Johnson4, Oliver Wieben1,4, Mark L. Schiebler1, and Christopher J. Francois1
1Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States, 2Global MR Applications and Workflow, GE Healthcare, Menlo Park, CA, United States, 3Global MR Applications and Workflow, GE Healthcare, Madison, WI, United States, 4Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, United States

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

 
2369.   CHRONOLOGICAL CARDIAC MRI ASSESSMENT OF CIRCUMFERENTIAL AND LONGITUDINAL STRAIN FOLLOWING MECHANICAL OBSTRUCTION OF CORONARY MICROVESSELS IN PRE-EXISTING INFARCT
Maythem Saeed1, Mohammed SA Suhail1,2, Loi Do1, Steve W. Hetts1, and Mark W. Wilson1
1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, United States, 2Radiology, University of California, San Diego, San Diego, California, United States

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

 
2370.   Evaluation of the feasibility to use novel tissue engineered grafts for right ventricular outflow tract reconstruction by magnetic resonance imaging
Dagmar Hartung1, Serghei Cebotari2, Igor Tudorache2, Karolina Theodoridis2, Tanja Meyer2, Alexandru Mogaldea2, Robert Ramm3, Katja Hueper1, Frank Wacker1, Andres Hilfiker3, and Axel Haverich2
1Radiology, Hannover Medical School, Hannover, Germany, 2Division of Cardiothoracic, Transplantation, and Vascular Surgery, Hannover Medical School, Hannover, Germany, 3Leibniz Research Laboratory for Biotechnology and Artificial Organs, Hannover Medical School, Hannover, Germany

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

 
2371.   Evaluation of cardiac function in cancer patients by wall motion kinetics using cine cardiac MRI: A feasability study
George Gentchos1, Caitlin Baran2, Michael Toth3,4, Hirak Der-Torossian5, Marion Couch5, and Kim Dittus6
1Radiology, University of Vermont, Burlington, VT, United States, 2College of Medicine, University of Vermont, Burlington, Vermont, United States, 3Department of Medicine, University of Vermont, Burlington, Vermont, United States, 4Molecular Physiology and Biophysics, University of Vermont, Vermont, United States, 5Surgery, University of Vermont, Burlington, Vermont, United States, 6Medicine, University of Vermont, Burlington, Vermont, United States

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

 
2372.   Compressed sensing undersampling strategies for accelerating 3D cine MRI in mouse hearts
Tobias Wech1,2, Andreas Schindele3, Victoria L Thornton4, Alfio Borzi3, Herbert Köstler1,2, and Jurgen E Schneider4
1Department of Radiology, University of Würzburg, Würzburg, Germany, 2Comprehensive Heart Failure Center, University of Würzburg, Würzburg, Germany, 3Institute of Mathematics, University of Würzburg, Würzburg, Germany, 4Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom

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

 
2373.   Fast free-breathing cardiac function assessment with automated segmentation using motion-corrected 2D multi-slice SSFP
Bailiang CHEN1,2, Laurent Bonnemains1,2, Pauline FERRY1,2, Anne MENNI1,2, Marine BEAUMONT1,3, Jacques FEBLINGER1,2, and Freddy ODILLE1,2
1IADI, Université de Lorraine, Nancy, Lorraine, France, 2U947, Inserm, Nancy, Lorraine, France, 3CIC-IT 801, Inserm, Nancy, Lorraine, France

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

 
2374.   Assessment of Longitudinal Changes in Contractile Function using DENSE in Patients with Myocardial Infarction
Christie McComb1,2, David Carrick3, Rosemary Woodward2,4, John McClure2, Aleksandra Radjenovic2, Colin Berry2,3, and John Foster1,2
1Clinical Physics, NHS Greater Glasgow & Clyde, Glasgow, United Kingdom, 2BHF Glasgow Cardiovascular Research Centre, Glasgow, United Kingdom, 3Cardiology, Golden Jubilee National Hospital, Glasgow, United Kingdom, 4MRI, Golden Jubilee National Hospital, Glasgow, United Kingdom

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

 
2375.   Applicability of real time imaging for assessing left-ventricular function in patients with acute ST elevation myocardial infarction at 3T.
Erica Dall'Armellina1, Nicole Seiberlich2, Keith Channon1, Adrian Banning3, Raj K Kharbanda3, Colin Forfar3, Bernard Prendergast3, Stefan Neubauer1, Robin Choudhury1, and Jurgen E. Schneider1
1RDM Cardiovascular Medicine, Oxford University, Oxford, Oxon, United Kingdom, 2Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States,3Heart Centre, Oxford NHS University Hospitals, Oxon, United Kingdom

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

 
 

TRADITIONAL POSTER SESSION ○ CARDIOVASCULAR
Myocardial Perfusion

 
Wednesday 14 May 2014
Traditional Poster Hall  13:30 - 15:30

2376.   Comparison of distributed parameter and Fermi modelling of cardiac MR perfusion with CT perfusion in coronary artery disease versus invasive coronary angiography
Giorgos Papanastasiou1,2, Michelle Williams2, Mark Dweck2, Saeed Mirsadraee1, Nick Weir3, Shirjel Alam2, Colin Stirrat2, David Newby1,2, and Scott Semple1,2
1Clinical Research Imaging Center, University of Edinburgh, Edinburgh, Lothian, United Kingdom, 2Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, Lothian, United Kingdom, 3NHS Medical Physics, University of Edinburgh, Edinburgh, Lothian, United Kingdom

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

 
2377.   Probing Myocardial Blood Oxygenation Reserve of Canines with Controlled Hypercapnia Using T2-prepared BOLD MR
Hsin-Jung Yang1, Roya Yumul1, Richard Tang1, Ivan Cokic1, Michael Klein2, Avinash Kali1, Olivia Sobczyk2, Behzad Sharif1, Jun Tang1, Xiaoming Bi3, Sotirios Tsaftaris4, Diabao Li1, Antonio Conte1, Joseph Fisher2, and Rohan Dharmakumar1
1Cedars Sinai Medical Center, Los Angeles, California, United States, 2University of Toronto, Toronto, ON, Canada, 3Siemens Medical Solutions, IL, United States, 4IMT Institute for Advanced Studies Lucca, Lucca, Italy

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

 
2378.   Radial versus Cartesian Sampling for Physiological Stress CMR Perfusion: A Head-to-Head Comparison
Silvio Pflugi1,2, Sébastien Roujol1, Mehmet Akçakaya1, Keigo Kawaji1, Murilo Foppa1, Bobby Heydari3, Beth Goddu1, Kraig V Kissinger1, Sophie Berg1, Warren J. Manning1,4, Sebastian Kozerke2, and Reza Nezafat1
1Department of Medicine, Beth Israel Deaconess Medical Center / Harvard Medical School, Boston, MA, United States, 2Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, 3Department of Medicine, Brigham and Women Hospital and Harvard Medical School, Boston, MA, United States, 4Department of Radiology, Beth Israel Deaconess Medical Center / Harvard Medical School, Brookline, MA, United States

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

 
2379.   Myocardial ASL with improved sensitivity to MBF using Parallel Imaging
Hung Phi Do1, Terrence R Jao2, and Krishna S Nayak3
1Department of Physics & Astronomy, University of Southern California, Los Angeles, California, United States, 2Biomedical Engineering Department, University of Southern California, Los Angeles, California, United States, 3Electrical Engineering Department, University of Southern California, Los Angeles, California, United States

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

 
2380.   Improved Spatial Resolution and Post-Processing for Myocardial Blood Flow Quantification in Humans using Steady-Pulsed Arterial Spin Labeling
Thomas Troalen1, Julien Pugnaire1, Thibaut Capron1, Benjamin Robert2, Monique Bernard1, and Frank Kober1
1Aix-Marseille Université, CNRS, CRMBM (Centre de Résonance Magnétique Biologique et Médiacle) UMR 7339, Marseille, France, 2Siemens Healthcare France SAS, Saint-Denis, France

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

 
2381.   Comparison of Reconstruction Methods for Accelerated Cardiac MR Stress Perfusion with Radial Sampling After Physiological Exercise
Silvio Pflugi1,2, Sébastien Roujol1, Mehmet Akçakaya1, Keigo Kawaji1, Murilo Foppa1, Bobby Heydari3, Beth Goddu1, Kraig V Kissinger1, Sophie Berg1, Warren J. Manning1,4, Sebastian Kozerke2, and Reza Nezafat1
1Department of Medicine, Beth Israel Deaconess Medical Center / Harvard Medical School, Boston, MA, United States, 2Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, 3Department of Medicine, Brigham and Women Hospital and Harvard Medical School, Boston, MA, United States, 4Department of Radiology, Beth Israel Deaconess Medical Center / Harvard Medical School, Brookline, MA, United States

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

 
2382.   Quantification of myocardial perfusion: A study of the number of readouts required for a radial acquisition with TV-constrained reconstruction
Devavrat Likhite1, Ganesh Adluru1, Srikant Kamesh Iyer1, and Edward DiBella1
1UCAIR/Radiology, University of Utah, Salt Lake City, Utah, United States

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

 
2383.   Temporal and Spatial Variation of Baseline Myocardial BOLD Signal Intensity in Cardiac Phase-Resolved BOLD MRI: A Potentially Revealing Insight into Dynamic Changes in Myocardial Oxygenation
Davide Boschetto1, Cristian Rusu1, Rohan Dharmakumar2,3, and Sotirios A. Tsaftaris1,4
1IMT Institute of Advanced Studies Lucca, Lucca, LU, Italy, 2Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States,3Medicine, University of California Los Angeles, Los Angeles, CA, United States, 4Electrical Engineering and Computer Science, Northwestern University, Evanston, IL, United States

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

 
2384.   The Effect of Bolus Dispersion in Semi-Quantitative and Quantitative Contrast-Enhanced Myocardial Perfusion MRI: A Computational Fluid Dynamics Simulation Study on Influencing Factors
Regine Schmidt1, Dirk Graafen1, Karsten Sommer1, Stefan Weber1, Hanns-Christian Breit1, and Laura Maria Schreiber1
1Section of Medical Physics, Department of Radiology, Johannes Gutenberg University Medical Center, Mainz, Germany

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

 
2385.   Dark rim artifacts from motion in highly accelerated 3D cardiac perfusion imaging
Haonan Wang1, Neal Kepler Bangerter1, Eugene Kholmovski2, Meredith Ireene Taylor1, and Edward V.R DiBella2
1Department of Electrical & Computer Engineering, Brigham Young University, Provo, UT, United States, 2Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, UT, United States

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

 
2386.   Whole-Heart Myocardial BOLD MRI with Adenosine Stress Using Fast Free-Breathing 3D T2 Mapping: A Validation Study in Canines
Hsin-Jung yang1, Richard Tang1, Avinash Kali1, Ivan Cokic1, and Rohan Dharmakumar1
1Cedars Sinai Medical Center, Los Angeles, California, United States

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

 
2387.   Kidney Segmentation in DCE-MRI Based on Curvelet Transform and Snake Model
Hao Li1, Bin Chen1, Xiaoying Wang1,2, and JUE ZHANG1,3
1Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, Beijing, China, 2Radiology, Peking University First Hospital, Beijing, Beijing, China, 3College of Enigneering, Peking University, Beijing, Beijing, China

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

 
2388.   Motion Correction for Free-Breathing Whole Heart T1 Mapping at 3 Tesla
Qian Tao1, Pieternel van der Tol1, Hildo J. Lamb1, and Rob J. van der Geest1
1Department of Radiology, Leiden University Medical Center, Leiden, Zuid Holland, Netherlands

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

 
2389.   Nonrigid 3D+t Image Registration for Temporal Averaging in Multiphase Coronary MR Angiography
Serena Y Yeung1, Nii Okai Addy1, R Reeve Ingle1, Bob S Hu1,2, and Dwight G Nishimura1
1Electrical Engineering, Stanford University, Stanford, CA, United States, 2Palo Alto Medical Foundation, Palo Alto, CA, United States

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

 
2390.   CMR Acceleration using iterative k-t-sparse SENSE reconstruction
Bradley D Allen1, Maria Carr1, Michael O Zenge2, Michaela Schmidt2, Mariappan S Nadar3, Bruce Spottiswoode4, Jeremy D Collins1, and James C Carr1
1Department of Radiology, Northwestern University, Chicago, IL, United States, 2Siemens AG, Healthcare Sector, Erlangen, Bavaria, Germany, 3Siemens Corporate Technology, Princeton, NJ, United States, 4Siemens Healthcare USA, Inc., Chicago, IL, United States

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

 
2391.   A Synthetic Generator of Myocardial Blood-Oxygen-Level-Dependent MRI Timeseries with Structural Sparse Decomposition Modeling
Cristian Rusu1, Rohan Dharmakumar2,3, and Sotirios A. Tsaftaris1,4
1IMT Institute for Advanced Studies Lucca, Lucca, Italy, 2Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States, 3Medicine, University of California, Los Angeles, CA, United States, 4Electrical Engineering and Computer Science, Northwestern University, Evanston, IL, United States

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

 
2392.   Development of an isolated MR-compatible working pig heart setup for structural and functional analysis of cardiac diseases
Fanny Vaillant1,2, Julie Magat1,2, Jérôme Naulin1,2, Virginie Loyer1,2, Delphine Vieillot3, Véronique Arsac1,2, Philippe Diolez1,2, and Bruno Quesson1,2
1IHU LIRYC, Pessac, France, 2Centre de Recherche Cardio-Thoracique de Bordeaux INSERM U1045, Université Bordeaux Segalen, France, 3Université Bordeaux Segalen, France

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

 
2393.   
Self-gated cardiac Cine MRI of the rat on a clinical 3T MRI system
Martin Krämer1, Karl-Heinz Herrmann1, Judith Biermann1, Sebastian Freiburger2, Michael Schwarzer2, and Jürgen R Reichenbach1
1Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital - Friedrich Schiller University Jena, Jena, TH, Germany,2Department of Cardiothoracic Surgery, Jena University Hospital - Friedrich Schiller University Jena, TH, Germany

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

 
2394.   
In vivo Cardiac MRI Development for Studying Zebrafish Models of Myocardial Disease
Niranchana Manivannan1, Kelly Banks2, Anna Bratasz3, Debra Wheeler2, Matthew Joseph2, Ryan Huttinger2, Ray E. Hershberger2, and Kimerly A. Powell3,4
1Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio, United States, 2Department of Internal Medicine, The Ohio State University, Ohio, United States, 3Small Animal Imaging Shared Resources, The Ohio State University, Ohio, United States, 4Department of Biomedical Informatics, The Ohio State University, Ohio, United States

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

 
2395.   The measurement of the characteristics of the metabolic syndrome and the effect of a targeted treatment of rosiglitazone
Ernst Suidgeest1, Bigit Den Adel1,2, José W.A. Van der Hoorn3, Rob E Poelmann4, and Louise Van der Weerd1,5
1Radiology, LUMC, Leiden, Netherlands, 2Anatomy, LUMC, Netherlands, 3Metabolic Health Research, TNO, Leiden, Netherlands, 4Anatomy, LUMC, Leiden, Netherlands,5Human Genetics, LUMC, Netherlands

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

 
2396.   Myocardial Function and Remodeling in a Baboon Model of Intrauterine Growth Restriction
Geoffrey David Clarke1, Jinqi Li2, Cun Li3, and Peter W Nathanielsz4
1Radiology, Univ Texas Health Science Center, San Antonio, TX, United States, 2Research Imaging Institute, Univ Texas Health Science Center, San Antonio, TX, United States, 3Obstetrics & Gynelocogy, Univ Texas Health Science Center, San Antonio, TX, United States, 4Obstetrics & Gynecology, Univ Texas Health Science Center, San Antonio, TX, United States

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

 
2397.   Cardiac Lipid Accumulation and Hypertrophy in a Murine Model of Non-alcoholic Fatty Liver
Ulrich Flögel1, Tomas Jelenik2, Jörg Kotzka2, Michael Roden2,3, Jürgen Schrader1, and Julia Szendroedi2,3
1Molecular Cardiology, Heinrich Heine University, Düsseldorf, NRW, Germany, 2Institute for Clinical Diabetology, German Diabetes Center, Düsseldorf, NRW, Germany,3Department of Endocrinology & Diabetology & Metabolic Diseases, German Diabetes Center, Düsseldorf, NRW, Germany

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

 
2398.   T2 mapping for the detection of myocardial edema in patients with acute myocarditis
Anirudh Mirakhur1, Yoko Mikami2, Khayam Khan2, Andrew Howarth2, and Naeem Merchant1,2
1Diagnostic Imaging, University of Calgary, Calgary, Alberta, Canada, 2Stephenson Cardiovascular MR Centre, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada

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

 
2399.   Spatial variability in cardiovascular magnetic resonance myocardial T2-mapping
Anirudh Mirakhur1, Yoko Mikami2, Khayam Khan2, Andrew Howarth2, and Naeem Merchant1,2
1Diagnostic Imaging, University of Calgary, Calgary, Alberta, Canada, 2Stephenson Cardiovascular MR Centre, Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada

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

 
2400.   Comparison of K-t SPIRiT and K-t GRAPPA for Accelerating Cardiac DCE and CINE MRI
Dan Zhu1, Feng Huang2, Feiyu Chen1, Haikun Qi1, Kui Ying3, Chun Yuan1, and Huijun Chen1
1Biomedical Engineering, Tsinghua University, Beijing, Beijing, China, 2Philips Healthcare, Florida, United States, 3Engineering Physics, Tsinghua University, Beijing, China

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

 
2401.   Relationship Between Diaphragmatic Motion and Heart Motion during Prolonged Breath-hold
Sébastien Roujol1, Warren J. Manning1,2, and Reza Nezafat1
1Department of Medicine, Beth Israel Deaconess Medical Center / Harvard Medical School, Boston, MA, United States, 2Department of Radiology, Beth Israel Deaconess Medical Center / Harvard Medical School, Boston, MA, United States

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

 
2402.   Smart QRS detection using wavelet transform for ECGs acquired inside MR scanner
Manivannan Jayapalan1 and Bhargav Bhatt1
1MR Software and Applications, GE Healthcare, Bangalore, Karnataka, India

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

 
2403.   Blood T1 value measurement in the left and right ventricles and aorta using postcontrast Look-Locker MR imaging at 1.5 T and 3.0 T: influence of location, heart rate, ejection fraction, and valvular regurgitation
Yasuo Amano1, Masaki Tachi1, and Makoto Obara2
1Nippon Medical School, Tokyo, Tokyo, Japan, 2Philips Asia Pacific, Tokyo, Japan

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

 
2404.   Comparison of TRUST, projection-based T2 imaging with susceptometry-based oximetry for the quantification of venous oxygen saturation
Suliman A. Barhoum1, Zachary B. Rodgers1, Michael C. Langham1, Jeremy F. Magland1, and Felix W. Wehrli1
1Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States

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

 
2405.   Optimized Two-Element Coil-Array for Cardiac Imaging in Mice at 9.4 T
Matthias Korn1, Titus Lanz1, Carsten Kögler1, Vicky Thornton2, and Jürgen E. Schneider2
1RAPID Biomedical GmbH, Rimpar, Germany, 2Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom

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

 
2406.   MRI-compatible exercise device for use in cardiac stress tests
Omid Forouzan1, Evan Flink1, Nick Thate1, Andrew Hanske1, Tongkeun Lee1, Alejandro Roldan-Alzate2,3, Christopher François3, Oliver Wieben2,3, and Naomi Chesler1
1Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States, 2Medical Physics, University of Wisconsin School of Medicine & Public Health, Madison, WI, United States, 3Radiology, University of Wisconsin School of Medicine & Public Health, Madison, WI, United States

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

 
2407.   Knowledge-Based Automatic Slice-Alignment Method in Cardiac Magnetic Resonance Imaging for Aortic Valve Evaluation: Comparison with Inter-observer Error
Rieko Ishimura1, Kenichi Yokoyama1, Toshiya Kariyasu1, Tatsuya Yoshioka2, Isao Miyazaki2, Shuhei Nitta3, Taichirou Shiodera3, Tomoyuki Takeguti3, Shigehide Kuhara4, Kuninori Kobayashi5, and Toshiaki Nitatori1
1Department of Radiology, Kyorin University School of Medicine, Mitaka-shi, Tokyo, Japan, 2Department of Radiology, Kyorin University Hospital, Mitaka-shi, Tokyo, Japan,3Toshiba Corporation R&D Center, Tokyo, Japan, 4Toshiba Medical Systems Corporation, Tochigi, Japan, 5Department of Medical Radiological Technology, Faculty of Health Science, Kyorin University, Hachiouji-shi, Tokyo, Japan

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

 
2408.   Non-Subtraction Dynamic Contrast Enhanced MR Angiography at 3T using IVD Sampling, Parallel Imaging and 2-pt Dixon
Kang Wang1, Mahdi Salmani Rahimi2, Courtney K Morrison3, Christopher J Francois4, James H Holmes1, and Frank R Korosec3,4
1Global MR Applications and Workflow, GE Healthcare, Madison, WI, United States, 2Biomedical Engineering, University of Wisconsin-Madison, WI, United States, 3Medical Physics, University of Wisconsin-Madison, WI, United States, 4Radiology, University of Wisconsin-Madison, WI, United States

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

 
2409.   MOWHARP: Multi-Oriented Windowed HARP Reconstruction for Robust Strain Imaging
Lucilio Cordero-Grande1, Javier Royuela-del-Val1, Marcos Martín-Fernández1, and Carlos Alberola-López1
1Universidad de Valladolid, Valladolid, Castilla y León, Spain

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

 
2410.   Free-Breathing Whole Heart CINE Imaging with Inversion Recovery Prepared SSFP Sequence: Feasibility for Myocardium Viability Assessment
Jing Liu1, Henrik Haraldsson2, Li Feng3, and David Saloner1
1University of California San Francisco, San Francisco, CA, United States, 2University of California San Francisco, CA, United States, 3New York University, NY, United States

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

 
2411.   Feasibility of whole heart DTI and IVIM with a 15 minute acquisition protocol
Martijn Froeling1,2, Gustav J. Strijkers2, Aart J. Nederveen3, Steven A.J. Chamuleau4, and Peter R. Luijten1
1Department of Radiology, University Medical Center, Utrecht, Netherlands, 2Biomedical NMR, Department of biomedical engineering, Eindhoven University of Technology, Eindhoven, Netherlands, 3Department of Radiology, Academic Medical Center, Amstredam, Netherlands, 4Department of Cardiology, Division Heart & Lung, University Medical Center, Utrecht, Netherlands

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

 
2412.   Accelerated Delayed Enhancement Imaging with Through-Time Radial GRAPPA
Ozan Sayin1, Haris Saybasili2, Henry Halperin3, M. Muz Zviman3, Mark Griswold4, Nicole Seiberlich5, and Daniel A. Herzka1
1Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, United States, 2Siemens Healthcare USA, Inc., Chicago, IL, United States,3Department of Radiology, Johns Hopkins Hospital, Baltimore, MD, United States, 4Department of Radiology, Case Western Reserve University, Cleveland, OH, United States, 5Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States

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

 
2413.   MRXCAT: Realistic Numerical Phantoms for Cardiac MRI
Lukas Wissmann1, William Paul Segars2, and Sebastian Kozerke1,3
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, 2Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, The Duke University Medical Center, Durham, North Carolina, United States, 3Division of Imaging Sciences & Biomedical Engineering, King's College London, London, United Kingdom

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

 
2414.   Combined T2-Preparation and 2D "Pencil Beam" Inner Volume Selection, Applied to Accelerated Reduced Field of View Coronary MRA
Andrew J Coristine1,2 and Matthias Stuber1,2
1Department of Radiology, University Hospital (CHUV) / University of Lausanne (UNIL), Lausanne, VD, Switzerland, 2CardioVascular Magnetic Resonance (CVMR) research centre, Centre for Biomedical Imaging (CIBM), Lausanne, VD, Switzerland

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

 
2415.   Free breathing (FB) motion corrected (MOCO) SSFP delayed enhanced imaging of left ventricular scar in patients with non-ischemic cardiomyopathy.
Oisin Flanagan1, Bruce Spottiswoode2, Maria Carr3, Jeremy Collins3, Sven Zuehlsdorff2, Jad Bou Ayache3, Marcos Botelho3, Xiaoming Bi4, Bradley D Allen3, Michael Markl3, Robert Edelman5, and James Carr1
1Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States, 2Siemens Healthcare, USA, IL, United States, 3Northwestern University Feinberg School of Medicine, IL, United States, 4Siemens Healthcare, IL, United States, 5Northshore Healthsystem, IL, United States

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

 
2416.   Image Quality Evaluation of Real-Time Cardiac Images Reconstructed using Linear and Golden Angle Through-Time Radial GRAPPA
Jesse I. Hamilton1, Prabhakar Rajiah2, Kestutis J. Barkauskas1, Katherine L. Wright1, Yun Jiang1, Vikas Gulani2, and Nicole Seiberlich1
1Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States, 2Radiology, University Hospitals, Cleveland, OH, United States

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

 
 

TRADITIONAL POSTER SESSION ○ CARDIOVASCULAR
Myocardial Tissue Characterization

 
Wednesday 14 May 2014
Traditional Poster Hall  13:30 - 15:30

2417.   Improvement of visualization of cardiac wall in diffusion-weighted imaging using cardiac triggering and acceleration motion correction
Tomoya Nakamura1, Shuhei Shibukawa1, Isao Muro1, Nao Kajihara1, Hiroaki Nishio1, Tetsuo Ogino2, Tetsu Niwa1, and Yutaka Imai1
1Tokai University Hospital, Isehara, Kanagawa, Japan, 2Philips Healthcare Asia Pacific, Tokyo, Japan

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

 
2418.   
DTI and Quantitative Histological Correlation of Diffuse Fibrosis in Failing Hearts
Osama Abdullah1, Stavros G Drakos2, Abdallah Kfoury3, Joseph Stehlik3, Craig H. Selzman3, Bruce B Reid3, Nikolaos A Diakos2, Kim Brunisholz3, Divya Ratan Verma3, Omar Wever-Pinzon3, Craig Myrick4, Dean Y Li2, and Edward W Hsu1
1Bioengineering, University of Utah, Salt Lake City, UT, United States, 2Molecular Medicine Program, University of Utah, UT, United States, 3UTAH Cardiac Transplant Program, UT, United States, 4Intermountain Donor Services, UT, United States

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

 
2419.   Magnetic resonance imaging assessment of excess cardiac iron in thalassemia major: when to initiate?
Xiaodong Chen1,2, Zuoquan Zhang3, Jinglian Zhong4, Qihua Yang4, Ziliang Cheng4, and Biling Liang4
1Sun Yat-Sen Memorial Hospital, Guang Zhou, Guang Dong, China, 2Guangdong Medical College, Guangdong, China, 3The Fifth Affiliated Hospital of Sun Yat-Sen University, Guangdong, China, 4Sun Yat-Sen Memorial Hospital, Guangdong, China

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

 
2420.   Microvascular obstruction is associated with greater extracellular matrix remodelling in the remote myocardium after infarction: A T1-mapping study
Venkat Ramanan1, Mohammad Zia2, Idan Roifman1, Bradley H Strauss1, Kim Connelly3, Graham A Wright1,4, and Nilesh Ghugre1,4
1Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada, 2Toronto East General Hospital, Toronto, Ontario, Canada, 3St Michaels Hospital, Toronto, Ontario, Canada, 4Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada

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

 
2421.   Correction for heart rate bias of post-contrast myocardial T1 values derived using MOLLI sequence
Neville D Gai1, Fabio Raman1, and David Bluemke1,2
1Radiology & Imaging Sciences, NIH, Bethesda, Maryland, United States, 2NIBIB, Bethesda, Maryland, United States

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

 
2422.   Comparing 3D-QALAS with MOLLI and Multi-Echo for in-vivo myocardial T1 and T2 quantification
Sofia Kvernby1,2, Marcel Warntjes1,2, Carl-Johan Carlhäll1,2, Jan Engvall1,2, and Tino Ebbers1,2
1Institution of Medical and Health Sciences, Linköping, Östergötland, Sweden, 2Center for Medical Image Science and Visualisation, Linköping, Östergötland, Sweden

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

 
2423.   Waveguide Magnetic Resonance Elastography of the Left Ventricle in a Pressure Varying Model
Ria Mazumder1, Bradley D. Clymer1, Richard D. White2, Anthony J. Romano3, and Arunark Kolipaka2
1Department of Electrical and Computer Engineering, The Ohio State University, Columbus, OH, United States, 2Department of Radiology, The Ohio State University, Columbus, OH, United States, 3Department of The Navy, Naval Research Laboratory, Washington, DC, United States

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

 
2424.   3D Wideband Late Gadolinium Enhancement (LGE) MRI for Patients with Implanted Cardiac Devices
Shams Rashid1, Stanislas Rapacchi1, Roderick Tung2, Kalyanam Shivkumar2, Daniel Ennis1, J. Paul Finn1, and Peng Hu1
1Department of Radiological Sciences, University of California, Los Angeles, Los Angeles, CA, United States, 2Cardiac Arrhythmia Center, University of California, Los Angeles, Los Angeles, CA, United States

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

 
2425.   Instantaneous Signal Loss simulation (InSiL) – An improved algorithm for myocardial T1 mapping using the MOLLI sequence
Jiaxin Shao1, Yutaka Natsuaki2, Bruce Spottiswoode2, Kim-Lien Nguyen1,3, and Peng Hu1,4
1Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, United States, 2Siemens Healthcare USA, Inc., IL, United States, 3Division of Cardiology, David Geffen School of Medicine, University of California, Los Angeles, CA, United States, 4Biomedical Physics Inter-Departmental Graduate Program, University of California, Los Angeles, CA, United States

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

 
2426.   Multi-parametric MRI assessment of myocardial ischemia-reperfusion injury in mice
Adrienne E Campbell-Washburn1, Rachel K Dongworth2, Thomas A Roberts3,4, Anthony N Price5, David L Thomas6, Roger J Ordidge7, Derek M Yellon2, Derek J Hausenloy2, and Mark F Lythgoe3
1Division of Intramural Research, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, United States, 2The Hatter Cardiovascular Institute, University College London, London, United Kingdom, 3Centre for Advanced Biomedical Imaging, University College London, London, United Kingdom, 4Centre for Mathematics and Physics in the Life Sciences & Experimental Biology, University College London, London, United Kingdom, 5Division of Imaging Sciences and Biomedical Engineering, St Thomas' Hospital, King's College London, London, United Kingdom, 6Department of Brain Repair and Rehabilitation, Institute of Neurology, University College London, London, United Kingdom, 7Centre for Neuroscience, University of Melbourne, Melbourne, Australia

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

 
2427.   In vivo 3D High Resolution Cardiac Diffusion Weighted MRI using Motion Compensated Diffusion-prepared Balanced Steady-State Free Precession Approach: Preliminary Application in Hypertrophic Cardiomyopathy Patients
Christopher Nguyen1,2, Zhaoyang Fan1, Behzad Sharif1, Yi He3, Tianjing Zhang4, Jing An4, Xiaoming Bi5, Minjie Lu6, Rohan Dharmakumar1, Daniel S Berman1, Shihua Zhao6, and Debiao Li1,2
1Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States, 2Bioengineering, University of California Los Angeles, Los Angeles, CA, United States, 3Radiology, Anzhen Hospital, Beijing, China, 4MR Collaborations NE Asia, Siemens Healthcare, Beijing, China, 5MR R&D, Siemens Healthcare, Los Angeles, CA, United States, 6State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, Beijing, China

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

 
2428.   UTE-based Reflection Point analysis for early diagnosis of infected cardiac valves in mice
Verena Hoerr1, Nina Nagelmann1, Janine Ring1, Arno Nauerth2, Michael Kuhlmann3, and Cornelius Faber1
1Department of Clinical Radiology, University Hospital Muenster, Muenster, Germany, 2Bruker BioSpin MRI GmbH, Ettlingen, Germany, 3European Institute for Molecular Imaging (EIMI), Muenster, Germany

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

 
2429.   In-vivo dual-phase cardiac DTI with 3D strain correction
Christian Torben Stoeck1, Aleksandra Kalinowska2, Constantin von Deuster1,3, Jack Harmer3, and Sebastian Kozerke1,3
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, 2Department of Mechanical and Biomedical Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States, 3Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom

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

 
2430.   Estimation of shear modulus in heart phantom using FE-simulated and MRE-measured displacements
Samad Javid1, David Lake1, Shivaram Poigai1, Arvin Arani1, Armando Manduca1, Kiaran McGee1, Richard Ehman1, Dan Dragomir-Daescu1, and Philip Araoz1
1Mayo Clinic, Rochester, MN, United States

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

 
2431.   Accuracy, Precision, and Reproducibility Comparison of T1 Mapping Sequences
Sébastien Roujol1, Sebastian Weingärtner1,2, Murilo Foppa1, Kelvin Chow3, Keigo Kawaji1, Kraig V Kissinger1, Beth Goddu1, Sophie Berg1, Peter kellman4, Warren J. Manning1,5, Richard B. Thompson3, and Reza Nezafat1
1Department of Medicine, Beth Israel Deaconess Medical Center / Harvard Medical School, Boston, MA, United States, 2Computer Assisted Clinical Medicine, University Medical Center Mannheim, Heidelberg University, Mannheim, Germany, 3Department of Biomedical Engineering, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada, 4National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, United States, 5Department of Radiology, Beth Israel Deaconess Medical Center / Harvard Medical School, Boston, MA, United States

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

 
2432.   Prognostic significance of late gadolinium enhancement patterns in patients with pulmonary hypertension
Andrew James Swift1, Smitha Rajaram2, Dave Capener3, Judith Hurdman4, Robin Condliffe4, Charlie Elliot4, Jim Wild3, and David G Kiely4
1University of Sheffield, Sheffield, S.Yorkshire, United Kingdom, 2Radiology Department, Sheffield Teaching Hospitals NHS Trust, S.Yorkshire, United Kingdom, 3University of Sheffield, S.Yorkshire, United Kingdom, 4Sheffield Pulmonary Vascular Disease Unit, Sheffield Teaching Hospitals NHS Trust, S.Yorkshire, United Kingdom

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

 
2433.   Comparison of Cardiac Diffusion Tensor and Generalized Q-Sampling MRI
Eric P. Aliotta1,2, Marmar Vaseghi3, Kalyanam Shivkumar3, and Daniel B. Ennis1,2
1Biomedical Physics IDP, University of California, Los Angeles, CA, United States, 2Department of Radiological Sciences, University of California, Los Angeles, CA, United States, 3Cardiac Arrhythmia Center & EP Programs, University of California, Los Angeles, CA, United States

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

 
2434.   Cardiac diffusion MRI beyond DTI
Valentina Mazzoli1, Martijn Froeling1,2, Aart J Nederveen3, Klaas Nicolay1, and Gustav J Strijkers1
1Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands, 2Department of Radiology, University Medical Center, Utrecht, Netherlands, 3Department of Radiology, Academic Medical Center, Amsterdam, Netherlands

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

 
2435.   An improved method for self-gated Cardiac T1 mapping in mice
Patrick Winter1, Thomas Kampf1, Xavier Helluy1, Fabian Tobias Gutjahr1, Cord Bastian Meyer1, Eberhard Rommel1, Wolfgang Rudolf Bauer2, Peter Michael Jakob1, and Volker Herold1
1University of Würzburg, Würzburg, Bavaria, Germany, 2Universitätsklinik Würzburg, Würzburg, Bavaria, Germany

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

 
2436.   Analysis and Design of Higher-Order Motion-Compensated Diffusion Encoding Schemes for In Vivo Cardiac DTI
Christopher Lee Welsh1,2, Edward VR DiBella2, and Edward W Hsu1
1Department of Bioengineering, University of Utah, Salt Lake City, UT, United States, 2Radiology, UCAIR, University of Utah, Salt Lake City, UT, United States

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

 
2437.   Detailing Myocardial Microstructure in the Ex Vivo Rat Heart Using High Isotropic Spatial Resolution Susceptibility Weighted MRI and Quantitative Susceptibility Mapping
Till Huelnhagen1, Andreas Pohlmann1, Fabian Hezel1, Eva Peper1, Min-Chi Ku1, and Thoralf Niendorf1,2
1Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine (MDC), Berlin, Germany, 2Experimental and Clinical Research Center, a joint cooperation between the Charite Medical Faculty and the Max Delbrueck Center, Berlin, Germany

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

 
2438.   Investigation of patient positioning and MRE driver placement on Cardiac MR Elastography
Shivaram Poigai Arunachalam1, Arvin Arani1, Roger Grimm1, Kiaran McGee2, and Philip Araoz1
1Radiology, Mayo Clinic, Rochester, MN, United States, 2Medical Physics, Mayo Clinic, Rochester, MN, United States

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

 
2439.   MICROSCOPIC VALIDATION DELAYED CONTRAST ENHANCED 3D INVERSION RECOVERY (IR) GRADIENT ECHO MRI IN BEATING AND NON-BEATING SWINE HEARTS
Maythem Saeed1, Robert Jablonowki1, Madhav Agrawal1, Steve W. Hetts1, and Mark W. Wilson1
1Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, United States

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

 
2440.   Reduction of Device Artifacts using Wideband Late Gadolinium Enhancement (LGE) MRI for Patients with Implanted Cardiac Devices: A Two-Center Study
Shams Rashid1, Adam Plotnik1, Harold Litt2, Yuchi Han3,4, Stanislas Rapacchi1, Roderick H Tung5, Kalyanam Shivkumar5, J. Paul Finn1,6, and Peng Hu1,6
1Department of Radiological Sciences, University of California, Los Angeles, Los Angeles, CA, United States, 2Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States, 3Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States, 4Penn Cardiovascular Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States, 5Cardiac Arrhythmia Center, University of California, Los Angeles, Los Angeles, CA, United States, 6Biomedical Physics Inter-Departmental Graduate Program, University of California, Los Angeles, Los Angeles, CA, United States

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

 
2441.   Effects of b-value and SNR in preclinical cardiac diffusion spectrum imaging
Irvin Teh1, Dunja Aksentijevic1,2, and Jurgen E Schneider1
1Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom, 2Cardiovascular Division, The Rayne Institute, King's College London, London, United Kingdom

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

 
2442.   Ex-Vivo Cardiac Fibre Imaging using Diffusion Tensor MRI and Optical Projection Tomography
Laurence Jackson1, Angela d'Esposito1, Bernard Siow1, Daniel J Stuckey1, and Mark F Lythgoe1
1Centre for Advanced Biomedical Imaging, University College London, London, London, United Kingdom

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

 
2443.   Myocardial T2* mapping free of distortion using susceptibility weighted RARE imaging at 7 Tesla
Katharina Fuchs1, Fabian Hezel1, Celal Oezerdem1, Lukas Winter1, and Thoralf Niendorf1,2
1Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany, 2Experimental and Clinical Resarch Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center, Berlin, Germany

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

 
2444.   Myocardial T1 and extracellular volume fraction related to cardiac functional parameters in dilated cardiomyopathy: modified Look-Locker imaging study
Masaki Tachi1, Yasuo Amano1, Minako Takeda1, Yoshio Matsumura1, Masashi Ogawa1, Makoto Obara2, Kuniya Asai3, Keisuke Inui3, and Shinichiro Kumita1
1Radiology, Nippon Medical School, Bunkyo-ku, Tokyo, Japan, 2Philips Asia Pacific, Tokyo, Japan, 3Cardiology, Nippon Medical School, Bunkyo-ku, Tokyo, Japan

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

 
2445.   Adaptive Registration of Varying Contrast-Weighted Images for Improved Tissue Characterization (ARCTIC): Application to T1 mapping
Sébastien Roujol1, Murilo Foppa1, Sebastian Weingärtner1,2, Warren J. Manning1,3, and Reza Nezafat1
1Department of Medicine, Beth Israel Deaconess Medical Center / Harvard Medical School, Boston, MA, United States, 2Computer Assisted Clinical Medicine, University Medical Center Mannheim, Heidelberg University, Mannheim, Germany, 3Department of Radiology, Beth Israel Deaconess Medical Center / Harvard Medical School, Boston, MA, United States

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

 
2446.   Heart rate adaptive inversion preparation and fat suppression for late gadolinium enhancement
Martin A Janich1, Jeffrey A Stainsby2, Piero Ghedin3, Glenn S Slavin4, David Stanley5, Maggie Fung6, Oleg Shubayev7, Steven D Wolff7, and Anja Brau3
1GE Global Research, Garching, Germany, 2GE Healthcare, Toronto, ON, Canada, 3GE Healthcare, Garching, Germany, 4GE Healthcare, Bethesda, MD, United States, 5GE Healthcare, Rochester, MN, United States, 6GE Healthcare, New York, NY, United States, 7Advanced Cardiovascular Imaging, New York, NY, United States

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

 
2447.   Polarity-Corrected TI Prep Tool for Delayed-Enhancement MR Imaging and T1 Mapping
Shigehide Kuhara1, Hironobu Ishikawa2, Takashi Kanazawa2, Shinya Seino2, Shuhei Bannae1, Hideaki Takasumi2, Takanori Sato2, and Takeshi Yusa2
1Toshiba Medical Systems Corporation, Otawara-shi, Tochigi, Japan, 2Department of Radiology, Fukushima Medical University Hospital, Fukushima, Japan

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

 
2448.   Whole Heart Free-breathing Extracellular Volume Mapping at 3.0 Tesla
Pieternel van der Tol1, Qian Tao1, Rob J. van der Geest1, and Hildo J. Lamb1
1Department of Radiology, Leiden University Medical Center, Leiden, Netherlands

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

 
2449.   Pilot Data on Inter-Centre and Inter-Vendor Comparison of MOLLI and ShMOLLI T1 Mapping Variants at 3T
David A Broadbent1,2, David M Higgins3, Vanessa Ferreira4, Alexander Liu4, Claudia Marini4, Christopher M Kramer5, Sven Plein1, Stefan Neubauer4,6, and Stefan K Piechnik4
1Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, United Kingdom, 2Division of Medical Physics, University of Leeds, Leeds, United Kingdom,3Philips Healthcare, Guildford, United Kingdom, 4Centre for Clinical Magnetic Resonance Research, University of Oxford, Oxford, United Kingdom, 5Department of Medicine and Radiology, University of Virginia Health System, Charlottesville, Virginia, United States, 6Division of Cardiovascular Medicine, University of Oxford, Oxford, United Kingdom

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

 
2450.   Determination of the myocardial extracellular volume using an ultra-fast T1 quantification sequence: implications for differentiation of myocardial damage
Daniel Gensler1,2, Philipp Mörchel2, Peter M. Jakob2,3, and Peter Nordbeck1
1Department of Internal Medicine I - Cardiology, University Hospital Würzburg, Würzburg, Bavaria, Germany, 2Research Center Magnetic-Resonance-Bavaria, Würzburg, Bavaria, Germany, 3Experimental Physics 5, University of Würzburg, Würzburg, Bavaria, Germany

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

 
2451.   Myocardial T1 mapping with a Saturation Recovery method using composite RF pulse - preliminary study
Kosuke Morita1,2, Daisuke Utsunomiya3, Seitaro Oda3, Tomohiro Namimoto2, Masanori Komi1, Mika Kitajima2, Toshinori Hirai2, Masahiro Hashida1, and Yasuyuki Yamashita2
1Radiology, Kumamoto university hospital, Kumamoto, Kumamoto, Japan, 2Diagnostic Radiology, Faculty of Life Sciences, Kumamoto university, Kumamoto, Kumamoto, Japan, 3Diagnostic Imaging Analysis, Faculty of Life Sciences, Kumamoto university, Kumamoto, Japan

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

 
2452.   Diffusion Tensor MRI of the remodeled living heart in multiple mechanical states: First experiments in a rat model of chronic myocardial infarction
Maelene Lohezic1, Remi Peyronnet2, Craig Lygate1, Peter Kohl2,3, and Jurgen E Schneider1
1Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom, 2National Heart and Lung Institute, Imperial College London, London, United Kingdom, 3Department of Computer Science, University of Oxford, Oxford, United Kingdom

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

 
2453.   An Analytic Description of Factors Affecting MOLLI’s Accuracy Using a Time-Weighted Average Model of T1 Relaxation
Kelvin Chow1 and Richard B Thompson1
1Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada

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

 
2454.   Combined sequence for integrated 2D LGE imaging and T1 Mapping in a single-scan
Sebastian Weingärtner1,2, Mehmet Akcakaya1, Sebastien Roujol1, Warren J Manning1,3, and Reza Nezafat1
1Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States, 2Computer Assisted Clinical Medicine, University Medical Center Mannheim, Heidelberg University, Mannheim, Germany, 3Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States

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

 
2455.   Dynamic T1-Quantification in Small Rodents: A Retrospective Approach with Variable Temporal Resolution
Fabian Tobias Gutjahr1, Thomas Kampf1, Xavier Helluy1, Patrick Winter2, Christian Herbert Ziener3, Peter Michael Jakob1,4, and Wolfgang Rudolf Bauer5
1Experimental Physics 5, University of Wuerzburg, Wuerzburg, Bavaria, Germany, 2Experimental Physics 5, University of Wuerzburg, Bavaria, Germany, 3DKFZ, Heidelberg, Baden Wuerttemberg, Germany, 4Magnetic Resonance Bavaria, Wuerzburg, Bavaria, Germany, 5Medizinische Klinik und Poliklinik I, Universitaetsklinikum Wuerzburg, Wuerzburg, Bavaria, Germany

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

 
2456.   Intrinsic motion correction for radial cardiac T2 mapping through alternating T2 preparation duration
Helene Feliciano1,2, Matthias Stuber1,2, and Ruud B. van Heeswijk1,2
1Radiology, University Hospital (CHUV), and University of Lausanne (UNIL), Lausanne, Switzerland, 2Center for Biomedical Imaging (CIBM), Lausanne, Switzerland

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

 
2457.   Detection and Validation of Localized Chronic Iron Deposition within Non-Reperfused Myocardial Infarctions
Avinash Kali1,2, Ivan Cokic1, Hsin-Jung Yang1,2, Richard Tang1, and Rohan Dharmakumar1,3
1Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States, 2Bioengineering, University of California, Los Angeles, CA, United States, 3Department of Medicine, University of California, Los Angeles, CA, United States

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

 
2458.   Myocardial T1 mapping at 3T by sampling inversion recovery with real time turboflash
Yanjie Zhu1, Yinzhu Gao1, Qi Yang2, Min Pan1, Xin Liu1, and Yiu-Cho Chung1
1Paul C. Lauterbur Research Centre for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China,2Radiology Department, Xuanwu Hospital Capital Medical University, Beijing, China

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

 
2459.   Free-Breathing 2D Myocardial T1 Mapping
Sebastian Weingärtner1, Sebastien Roujol2, Mehmet Akcakaya2, Tamer Basha3, Warren J Manning2,4, and Reza Nezafat2
1Cardiac MR Center, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States, 2Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States, 3Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, United States, 4Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States

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

 
2460.   Taui, A Metabolic Imaging Biomarker for Myocardium
William D Rooney1, Craig S Broberg2, and Charles S Springer, Jr.1
1Advanced Imaging Research Center, Oregon Health & Science University, Portland, Oregon, United States, 2Division of Cardiovascular Medicine, Oregon Health & Science University, Portland, Oregon, United States

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

 
2461.   Dynamic changes of myocardial salvage index after reperfusion: A rat study at 7T
Rui Xia1, Xi Lu1, Bing Zhang1, Yuqing Wang1, Jie Zheng2, and Fabao Gao1
1Department of radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China, 2Mallinckrodt Institute of Radiology, Washington University School of Medicine in St. Louis, Missouri, United States

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

 
2462.   Three-Dimensional Late Gadolinium Enhancement with Adaptive Inversion Time
Markus Henningsson1, Frank Eschbach1,2, Giel Mens3, Reza Nezafat4, Sebastien Roujol4, and Rene Botnar1
1Imaging Sciences & Biomedical Engineering, King's College London, London, United Kingdom, 2Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands, 3Philips Healthcare, Best, Netherlands, 4Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States

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

 
2463.   Dual Manganese- and Gadolinium-Enhanced Cardiac MRI Delineates the Peri-Infarct Region in Patients with Severe Ischemic Cardiomyopathy
Rajesh Dash1, Yuka Matsuura1, Paul J Kim1, Hadas Shiran1, Phillip Harnish2, Michael V McConnell1,3, and Phillip C. Yang1
1Stanford University, Stanford, CA, United States, 2Eagle Vision Pharmaceutical Corporation, PA, United States, 3Engineering, Stanford University, Stanford, CA, United States

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

 
 

TRADITIONAL POSTER SESSION ○ CARDIOVASCULAR
Velocity & Flow Imaging

 
Wednesday 14 May 2014
Traditional Poster Hall  13:30 - 15:30

2464.   
Visualization of Aortic Root Vortex and Aortic Flow for Symptomatic Marfan Syndrome Patients by Phase-Contrast MRI
Hung-Hsuan Wang1, Hsin-Hui Chiu2, Wen-Yih Isaac Tseng3, and Hsu-Hsia Peng1
1Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan, 2Pediatrics, Taipei Medical University Hospital, Taipei, Taiwan,3Center for Optoelectronic Biomedicine, College of Medicine, National Taiwan University, Taipei, Taiwan

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

 
2465.   An adaptive phase recovery method for 4D phase-contrast MRI
Rizwan Ahmad1, Ning Jin2, Yu Ding3, and Orlando P Simonetti3
1Electrical Engineering, The Ohio State University, Columbus, OH, United States, 2Siemens Healthcare, Columbus, OH, United States, 3Internal Medicine, The Ohio State University, Columbus, OH, United States

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

 
2466.   
Comparison between magnitude and direction of 4D phase contrast MRI based and computational fluid dynamics based wall shear stress calculations in healthy carotid bifurcations
Wouter V Potters1, Merih Cibis2, Frank JH Gijsen2, Henk A Marquering1, Ed vanBavel3, Jolanda Wentzel2, and Aart J Nederveen1
1Radiology, Academic Medical Center, Amsterdam, Netherlands, 2Biomedical Engineering, Erasmus Medical Center, Rotterdam, Netherlands, 3Biomedical Engineering & Physics, Academic Medical Center, Amsterdam, Netherlands

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

 
2467.   
On the Quantification of Turbulent Kinetic Energy using Phase-Contrast MRI
Christian Binter1, Utku Gülan2, Verena Knobloch1, Markus Holzner2, and Sebastian Kozerke1,3
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, 2Institute of Environmental Engineering, ETH Zurich, Zurich, Switzerland, 3Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom

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

 
2468.   3D Blood flow Characteristic in the Left and Right Atrium in Patients with Atrial Fibrillation
Maria Carr1, Yuqing Liu2, Jason Ng3, James C Carr1, Daniel Lee3, Jeffrey Goldberger3, and Michael Markl1,2
1Radiology, Northwestern University, Chicago, Illinois, United States, 2Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States,3Division of Cardiology, Northwestern University, Chicago, Illinois, United States

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

 
2469.   
Estimation of transvalvular flow jet angle using 4D flow MRI and flow jet shear layer detection
Julio Garcia1, Michael Markl1,2, Pim van Ooij1, Susanne Schnell1, Jeremy Collins1, S. Chris Malaisrie3, James Carr1, and Alex J. Barker1
1Radiology, Northwestern University, Chicago, Illinois, United States, 2Biomedical Engineering, Northwestern University, Illinois, United States, 3Division of Cardiac Surgery, Northwestern University, Chicago, Illinois, United States

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

 
2470.   Quantitative Analysis of Vortex Flow Patterns in 4D Flow Measurements
Jochen von Spiczak1, Gérard Crelier2, Daniel Giese1, Sebastian Kozerke2, David Maintz1, and Alexander Christian Bunck1
1Department of Radiology and Neuroradiology, University Hospital of Cologne, Cologne, Germany, 2Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland

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

 
2471.   
Pressure Gradient Measurement in the Coronary Artery Using View-Shared (VS) 4D PC-MRI: Towards Noninvasive Quantification of Fractional Flow Reserve
Zixin Deng1,2, Guoxi Xie3, Yi He4, Nan Zhang4, Yutaka Natsuaki5, Ning Jin5, Xiaoming Bi5, Jing An6, Xin Liu3, Zhaoqi Zhang4, Zhanming Fan4, Debiao Li1,2, and Zhaoyang Fan1
1Biomedical Imaging Research Institute (BIRI), Cedars-Sinai Medical Center, Los Angeles, CA, United States, 2Department of Bioengineering, UCLA, Los Angeles, California, United States, 3Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, 4Department of Radiology, Anzhen Hospital, Beijing, China,5MR R&D, Siemens Healthcare, Los Angeles, California, United States, 6MR Collaborations NE Asia, Siemens Healthcare, Beijing, China

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

 
2472.   Identification of Systematic Differences Between Different Methods for Extracting Pulse Wave Velocity with 4D Flow MRI
Petter Dyverfeldt1, Tino Ebbers1, and Toste Länne1,2
1CMIV and Linköping University, Linköping, Sweden, 2County Council of Östergötland, Linköping, Sweden

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

 
2473.   Wall shear stress quantification and reproducibility using variable VENC 4D phase contrast MRI in the aorta
Wouter V Potters1, Anders Nilsson2, Sandra van den Berg1, Ed vanBavel3, Karin Markenroth Bloch4, Freddy Ståhlberg2,5, and Aart J Nederveen1
1Radiology, Academic Medical Center, Amsterdam, Netherlands, 2Medical Radiation Physics, Lund University, Lund, Sweden, 3Biomedical Engineering & Physics, Academic Medical Center, Amsterdam, Netherlands, 4Philips Healthcare, Lund, Sweden, 5Diagnostic Radiology, Lund University, Lund, Sweden

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

 
2474.   Identifying regions of abnormal wall shear stress in patients with bicuspid aortic valves
Pim van Ooij1, Maria Carr1, Bradley D. Allen1, David G. Guzzardi2, Jeremy Collins1, James Carr1, S. Chris Malaisrie3, Paul W. M. Fedak2, Patrick McCarthy4, Michael Markl1,5, and Alex J. Barker1
1Radiology, Northwestern University, Chicago, IL, United States, 2Cardiac Surgery, University of Calgary, Calgary, Alberta, Canada, 3Medicine-Cardiology, Northwestern University, Chicago, IL, United States, 4Surgery-Cardiac Surgery, Northwestern University, Chicago, IL, United States, 5Biomedical Engineering, Northwestern University, Chicago, IL, United States

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

 
2475.   Optimization of Short-TE Phase Contrast Flow Quantification
Brett Cowan1, Yingmin Liu1, Alistair Young1, Andreas Greiser2, and Peter Speier2
1University of Auckland, Auckland, Auckland, New Zealand, 2Siemens AG Healthcare Sector, Erlangen, Germany

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

 
2476.   Advanced respiratory navigator strategies for 4D flow MRI
Pim van Ooij1, Edouard Semaan1, Zoran Stankovic1, Susanne Schnell1, Shivraman Giri2, Alex J Barker1, and Michael Markl1,3
1Radiology, Northwestern University, Chicago, IL, United States, 2Siemens Healthcare, Chicago, IL, United States, 3Biomedical Engineering, Northwestern University, Chicago, IL, United States

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

 
2477.   Assessment of Aortic Stenosis Severity using Bayesian Multipoint Phase-Contrast MRI
Christian Binter1, Alexander Gotschy1,2, Robert Manka1,2, Simon H. Sündermann3, and Sebastian Kozerke1,4
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, 2Dept. of Cardiology, University Hospital Zurich, Zurich, Switzerland, 3Division of Cardiovascular Surgery, University Hospital Zurich, Zurich, Switzerland, 4Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom

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

 
2478.   Comparison of phase-contrast MRI and arterial tonometry pulse wave velocity quantification in young and old healthy subjects
Erin K Englund1, Zachary B Rodgers1, Prithvi Shiva Kumar2, Michael C Langham3, Julio A Chirinos2, Raymond R Townsend2, and Felix W Wehrli3
1Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States, 2Department of Medicine, University of Pennsylvania, Philadelphia, PA, United States, 3Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States

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

 
2479.   Assessment and Quantification of Aortic Stenosis Hemodynamics with 4D Flow: Comparison with Doppler Echocardiography
MJ Negahdar1,2, Mo Kadbi1, Michael Kendrick3, Rita Longaker4, Marcus Stoddard4, and Amir Amini1,2
1Electrical and Computer Engineering, University of Louisville, Louisville, KY, United States, 2Division of Research, VA Medical Center, Louisville, KY, United States,3Department of Radiology, VA medical center, KY, United States, 4Cardiovascular Division, University of Louisville, KY, United States

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

 
2480.   Does phase contrast MRI provide the mean velocity of the spins within a voxel?
Eduardo G. Gonzalez1 and Joao L. A. Carvalho1
1Department of Electrical Engineering, University of Brasilia, Brasilia, DF, Brazil

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

 
2481.   Influence of Uterine Artery Blood Flow and Abdominal Aortic Hemodynamics: Implications for Sex Dependent AAA development
Elizabeth Iffrig1, Pardeep Mittal2, Gail Peters2, John Oshinski1,2, and William Robert Taylor1,3
1Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States, 2Radiology, Emory University, Georgia, United States, 3Cardiology, Emory University, Georgia, United States

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

 
2482.   Improved Semi-automated Pulse Wave Velocity Analysis in the Thoracic Aorta using 4D flow MRI
Patrick Magrath1, Michael Markl1,2, Aurelien F. Stalder3, Mehmet A. Gulsun4, and Bruce Spottiswoode5
1Biomedical Engineering, Northwestern University, Chicago, Illinois, United States, 2Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States, 3Siemens AG Healthcare sector, Erlangen, Germany, 4Imaging and Computer Vision, Siemens Corporation, Princeton, New Jersey, United States, 5Cardiovascular MR R&D, Siemens Healthcare, Chicago, Illinois, United States

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

 
2483.   Evaluation of mitral inflow in a rat model of aortic stenosis using phase contrast MRI
Kristine Skårdal1,2, Emil K. S. Espe1,2, Magnus Aronsen1,2, Lili Zhang1,2, and Ivar Sjaastad1,2
1Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Oslo, Norway, 2KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Oslo, Norway

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

 
2484.   Train velocity encoded phase contrast MR imaging for pulsatile velocity analysis with improved temporal resolution and velocity-to-noise ratio
Pan-Ki Kim1, Jeongmin Kwon1, Hyeonjin Kim1,2, Eun-Ah Park1,2, and Whal Lee1,2
1Seoul National University, Seoul, Korea, 2Seoul National Univ. Hospital, Seoul, Korea

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

 
2485.   Enforcing divergence free to velocity data from 4D flow MR images
Alejandro Matias Pino Verdugo1,2, Joaquin Mura3, and Sergio Uribe2,4
1Physics Department, Pontificia Universidad Católica de Chile, Santiago, Santiago, Chile, 2Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Santiago, Chile, 3Civil Engineering School, Pontificia Universidad Católica de Valparaiso, Valparaiso, Chile, 4Radiology Department School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile

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

 
2486.   Analysis of Hemodynamic Parameters for Symptomatic Marfan Syndrome Patients by Phase-Contrast MRI
Hung-Hsuan Wang1, Hsin-Hui Chiu2, Shih-Han Hung3, Wen-Yih Isaac Tseng4, and Hsu-Hsia Peng1
1Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan, 2Pediatrics, Taipei Medical University Hospital, Taipei, Taiwan,3Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan, 4Center for Optoelectronic Biomedicine, College of Medicine, National Taiwan University, Taipei, Taiwan

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

 
2487.   Phase Contrast MRI with Flow Compensation View Sharing (FCVS)
Da Wang1,2, Jiaxin Shao1, Stanislas Rapacchi1, Matthew J. Middione1,2, Yutaka Natsuaki3, Gerhard Laub3, Daniel B. Ennis1,2, and Peng Hu1,2
1Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, United States, 2Biomedical Physics Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, California, United States, 3SIEMENS, California, United States

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

 
2488.   MR Flow Imaging Reveals Unique Flow Patterns Linked to Different Leaflet Fusions with Bicuspid Aortic Valve
Nicholas Scott Burris1, Monica Sigovan2, David Saloner1, and Michael Douglas Hope1
1Radiology, University of California San Francisco, San Francisco, CA, United States, 2University of Lyon, CREATIS Laboratory, Lyon, France

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

 
2489.   Comparison between Cartesian and Spiral MR flow imaging of stenotic flow.
Sven Petersson1, Petter Dyverfeldt1, Andreas Sigfridsson2, Carl Johan Carlhäll1,3, and Tino Ebbers1
1CMIV and Linköping University, Linköping, Sweden, 2Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden, 3Department of Clinical Physiology, County Council of Östergötland, Linköping, Sweden

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

 
2490.   Computational fluid dynamics simulations guided by 3D PC-MRI data
Vinicius C. Rispoli1,2, Jon-Fredrik Nielsen3, Krishna S. Nayak4, and Joao L. A. Carvalho1
1Department of Electrical Engineering, University of Brasilia, Brasilia, DF, Brazil, 2UnB Gama Faculty, University of Brasilia, Brasilia, DF, Brazil, 3Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States, 4Electrical Engineering, University of Southern California, Los Angeles, CA, United States

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

 
2491.   Determination of Age-Related Regional Pulse Wave Velocity with 4D Flow MRI
Petter Dyverfeldt1, Tino Ebbers1, and Toste Länne1
1CMIV and Linköping University, Linköping, Sweden

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

 
2492.   Quantification of Wall Shear Stress using Finite-Element Interpolations in Multidimensional Phase Contrast MR data of the Thoracic Aorta
Julio Sotelo1,2, Jesús Urbina3,4, Ernesto Ortiz5, Cristian Tejos3,6, Israel Valverde7,8, Daniel E. Hurtado5,9, and Sergio Uribe3,4
1Biomedical Imaging Center, Pontificia Universidad Catolica de Chile, Santiago, Santiago, Chile, 2Electrical Engineering, Pontificia Universidad Catolica de Chile, Santiago, Santiago, Chile, 3Biomedical Imaging Center, Pontificia Universidad Catolica de Chile, Santiago, Chile, 4Radiology, School of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile, 5Structural Engineering, Pontificia Universidad Catolica de Chile, Santiago, Chile, 6Electrical Engineering, Pontificia Universidad Catolica de Chile, Santiago, Chile, 7Pediatric Cardiology Unit, Hospital Virgen del Rocio, Sevilla, Spain, 8Division of Cardiovascular Physiology, Institute of Biomedicine Seville (IBIS), Hospital Universitario Virgen de Rocio/CSIC/University of Seville, Sevilla, Spain, 9Biomedical Engineering Group, Pontificia Universidad Catolica de Chile, Santiago, Chile

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

 
2493.   Semi-Automation of Myocardial Tissue Phase Mapping Segmentation and Analysis
Patrick Magrath1, Alex J. Barker2, Timothy J. Carroll1,2, and Michael Markl1,2
1Biomedical Engineering, Northwestern University, Chicago, Illinois, United States, 2Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States

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

 
2494.   Quantitative assessment of spatial and temporal pulmonary arterial regurgitation after repaired Tetralogy of Fallot
Pei-Hsin Wu1, Hsiao-Wen Chung1, Cheng-Wen Ko2, and Ming-Ting Wu3
1Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan, 2Department of Computer Science and Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan, 3Department of Radiology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan

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

 
2495.   The Effect of Phase Cross-contamination by Partial Central K-space in Cine Phase Contrast MRI
Teng-Chieh Cheng1, Yi-Jui Liu1, Yi-Hsiung Lee2, Wen-Chau Wu3, Teng-Yi Huang4, Chao-Chun Lin5, Chia-Wei Lin5, and Wu-Chung Shen5
1Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan, 2Ph.D. Program of Electrical and Communications Engineering, Feng China University, Taichung, Taiwan, 3Graduate Institute of Oncology, National Taiwan University, Taipei, Taiwan, 4Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan, 5Department of Radiology, China Medical University Hospital, Taichung, Taiwan

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

 
2496.   Investigation of flow instabilities in branch pulmonary arteries after repaired Tetralogy of Fallot
Pei-Hsin Wu1, Hsiao-Wen Chung1, Ming-Ting Wu2, and Cheng-Wen Ko3
1Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan, 2Department of Radiology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, 3Department of Computer Science and Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan

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

 
2497.   Examining the distribution of the local pulse wave velocity in mice using a k-t BLAST QA-method
Volker Herold1, Alexander Gotschy1, Patrick Winter1, Eberhard Rommel1, Wolfgang Rudolf Bauer2, and Peter Michael Jakob1
1University of Wuerzburg, Wuerzburg, Bavaria, Germany, 2Medizinische Universitätsklinik, University of Wuerzburg, Bavaria, Germany

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

 
2498.   Functional Analysis of Thoracic Stent Grafts after Thoracic Endovascular Aortic Repair (TEVAR)
Volker Rasche1, Robert Kohlschmitt2, David Schahbasian2, Karl-Heinz Orend2, and Alexander Oberhuber2
1Internal Medicine II, Ulm University, Ulm, BW, Germany, 2Thoracic and Vascular Surgery, Ulm University, BW, Germany

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

 
2499.   Reduced FOV velocity mapping by complex subtraction unfolding
Maya Khalifé1, Ludovic de Rochefort1, Dima Rodriguez1, and Emmanuel Durand1
1Imagerie par Résonance Magnétique Médicale et Multi-modalités (IR4M), Université Paris-Sud- CNRS, Orsay, France

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

 
2500.   Aortic Compliance Evaluation in 291 Normal Studies
Yi Wang1, Yang Cheng1, and Marguerite Roth1
1St. Francis Hospital, Roslyn, NY, United States

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

 
2501.   CS-SENSE Phase Contrast Imaging of the Right Pulmonary Artery
Jonathan M. Chia1 and Zhiyue J. Wang2,3
1Philips Healthcare, Cleveland, OH, United States, 2Children's Medical Center, Dallas, Texas, United States, 3University of Texas Southwestern, Dallas, Texas, United States

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

 
2502.   Blood flow velocity and pulsatility analysis of cerebral small perforating arteries with 7 Tesla quantitative flow MRI.
Willem Bouvy1, Geert Jan Biessels2, Jaap Kappelle2, Peter R Luijten3, and Jaco Zwanenburg3
1Brain Center Rudolf Magnus, Department of Neurology, Utrecht University Medical Centre, Utrecht, Utrecht, Netherlands, 2Brain Center Rudolf Magnus, Department of Neurology, Utrecht University Medical Centre, Utrecht, Netherlands, 3Department of Radiology, Utrecht University Medical Centre, Utrecht, Netherlands

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

 
 

TRADITIONAL POSTER SESSION ○ CARDIOVASCULAR
CE & Non-CE MRA

 
Wednesday 14 May 2014
Traditional Poster Hall  13:30 - 15:30

2503.   Automated and Subject-Specific Coil Selection for Respiratory Self-Navigation in Coronary MRA
Davide Piccini1,2, Bénédicte Maréchal1,3, Simone Coppo2, Jérôme Chaptinel2, Gabriele Bonanno2, Gunnar Krueger1,3, Juerg Schwitter4, and Matthias Stuber2
1Advanced Clinical Imaging Technology, Siemens Healthcare IM BM PI, Lausanne, Switzerland, 2Department of Radiology, University Hospital (CHUV) and University of Lausanne (UNIL) / Center for Biomedical Imaging (CIBM), Lausanne, Switzerland, 3CIBM-AIT, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 4Division of Cardiology and Cardiac MR Center, University Hospital of Lausanne (CHUV), Lausanne, Switzerland

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

 
2504.   Initial Evaluation of the Utility of Ferumoxytol for MR Runoffs
Thomas Hope1, Rizwan Aslam1, Judy Yee1, Anait Sesi1, Joseph Rapp1, Christopher Owens1, and David Saloner1
1Department of Radiology, UCSF/SFVA, San Francisco, CA, United States

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

 
2505.   Post-Contrast Inversion Recovery Self-Navigated 3D Whole-Heart MRI for Combined Coronary Tree and Scar Tissue Visualization
Davide Piccini1,2, Simone Coppo2, Tobias Rutz3, Giulia Ginami2, Jean-Baptiste Ledoux4, Mathieu Gerber4, Juerg Schwitter3, and Matthias Stuber2
1Advanced Clinical Imaging Technology, Siemens Healthcare IM BM PI, Lausanne, Switzerland, 2Department of Radiology, University Hospital (CHUV) and University of Lausanne (UNIL) / Center for Biomedical Imaging (CIBM), Lausanne, Switzerland, 3Division of Cardiology and Cardiac MR Center, University Hospital of Lausanne (CHUV), Lausanne, Switzerland, 4Department of Radiology, University Hospital of Lausanne (CHUV), Lausanne, Switzerland

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

 
2506.   
High Resolution Variable-Density 3D Cones Coronary MRA
Nii Okai Addy1, R Reeve Ingle1, Dwight G Nishimura1, and Bob S Hu1,2
1Electrical Engineering, Stanford University, Stanford, CA, United States, 2Cardiology, Palo Alto Medical Foundation, Palo Alto, CA, United States

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

 
2507.   Validation of a Cardiovascular MRI Protocol for Combined Assessment of Contrast-Enhanced Whole Body Angiography and Cardiac Function within a Single Examination
Stephen J Gandy1, Jill Belch2, Ian Cavin1, Elena Crowe3, Jennifer Macfarlane1, Patricia Martin3, Shona Matthew2, Matthew Lambert2, R Stephen Nicholas1, Allan Struthers2, Shelley Waugh1, Jonathan Weir-McCall2, Richard White3, and J Graeme Houston2
1NHS Tayside Medical Physics, Ninewells Hospital, Dundee, Angus, United Kingdom, 2School of Medicine, University of Dundee, Dundee, Angus, United Kingdom, 3NHS Tayside Clinical Radiology, Ninewells Hospital, Dundee, Angus, United Kingdom

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

 
2508.   Highly accelerated non-contrast-enhanced MR angiography of the renal arteries featuring sparse, incoherent sampling and L1-regularized iterative SENSE
Michaela Schmidt1, Stefan Haneder2, Ulrike I. Attenberger2, Melissa M. Ong2, Mariappan Nadar3, Peter Schmitt1, Xiaoming Bi4, Stefan O. Schoenberg2, and Michael O. Zenge1
1Siemens AG Healthcare Sector, Erlangen, Germany, 2University Medical Centre Mannheim, Institute of Clinical Radiology and Nuclear Medicine, Germany, 3Siemens Corporate Technology, Princeton, NJ, United States, 4Siemens Healthcare, LA, CA, United States

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

 
2509.   
A MRI-based framework for the analysis of aortic morphometry: a first application to diastolic dysfunction.
Orestis Vardoulis1, Diego Gallo2, Davide Piccini3,4, Pierre Monney5, Umberto Morbiducci2, Gabriele Bonanno3, Nikos Stergiopulos1, and Juerg Schwitter5
1LHTC-IBI-STI, EPFL, Lausanne, Vaud, Switzerland, 2Mechanics Department, Politecnico di Torino, Piemonte, Italy, 3Center for Biomedical Imaging (CIBM), Department of Radiology, University Hospital (CHUV) and University of Lausanne (UNIL), Vaud, Switzerland, 4Siemens Healthcare IM BM PI, Advanced Clinical Imaging Technology, Vaud, Switzerland, 5Centre de la RM cardiaque, CHUV, Vaud, Switzerland

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

 
2510.   Assessment of reproducibility in Whole-Heart Magnetic Resonance Coronary Angiography
Yuki Ohmoto-Sekine1, Junji Takahashi2, Makiko Ishihara3, Takashi Yoshida2, Sachiko Isono4, Shigehide Kuhara4, Yasuji Arase1, and Mitsue Miyazaki5
1Health Management Center, Toranomon Hospital, Tokyo, Japan, 2Radiology Dept., Toranomon Hospital, Tokyo, Japan, 3Imaging Center, Toranomon Hospital, Tokyo, Japan, 4Toshiba Medical Systems, Tochigi, Japan, 5Toshiba Medical Research Institute, Illinois, United States

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

 
2511.   Sliding Time of Flight (TOF) using a tornado filter
Joonsung Choi1, Yeji Han1, and HyunWook Park1
1Department of Electrical Engineering, KAIST, Daejeon, Korea

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

 
2512.   Improving 4D pCASL angiography by combining Hadamard time-encoding with Look-Locker readout
Yuriko Suzuki1, Wouter M Teeuwisse2, Sophie Schmid2, Michael Helle3, Marc Van Cauteren4, and Matthias JP van Osch2
1Philips Electronics Japan, Minato-ku, Tokyo, Japan, 2C.J.Gorter Center for High Field MRI, Departement of Radiology, Leiden University Medical Center, Leiden, Netherlands, 3Philips Research Laboratories, Hamburg, Germany, 4Philips Healthcare Asia Pasific, Tokyo, Japan

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

 
2513.   Non-contrast-enhanced MR angiography of the thoracic central veins
Andrew Nicholas Priest1, Gavin Low1, Martin John Graves1, and David John Lomas1
1Radiology, Addenbrooke's Hospital and University of Cambridge, Cambridge, United Kingdom

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

 
2514.   Dual vessel labeling scheme for non-contrast time-resolved MR angiography
Masanobu Nakamura1, Masami Yoneyama2, Makoto Obara1, Atsushi Takemura1, Taro Takahara3, and Marc Van Cauteren1
1Philips Electronics Japan, Tokyo, Japan, 2Yaesu clinic, Tokyo, Japan, 3Tokai University School of Engineering, Kanagawa, Japan

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

 
2515.   Respiratory Displacement-Dependent Weighting of the Center of K-Space for Improved Image Quality in Self-Navigated Golden Angle 3D Radial Whole-heart Coronary MRA
Jerome Chaptinel1,2, Davide Piccini3,4, Simone Coppo1,2, Gabriele Bonanno1,2, and Matthias Stuber1,2
1Department of Radiology, University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland, 2Center for Biomedical Imaging (CIBM), Lausanne, Switzerland, 3Advanced Clinical Imaging Technology, Siemens Healthcare IM BM PI, Lausanne, Switzerland, 4Department of Radiology, University Hospital (CHUV) and University of Lausanne (UNIL) / Center for Biomedical Imaging (CIBM), Lausanne, Switzerland

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

 
2516.   Improved SNAP with Mask-based Venous Flow Suppression
Haining Liu1, Zechen Zhou2, Jinnan Wang3, and Chun Yuan2,4
1Bioengineering Department, University of Washington, Seattle, WA, United States, 2Bioengineering Department, Tsinghua University, Beijing, China, 3Philips Research North America, NY, United States, 4Radiology Department, University of Washington, WA, United States

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

 
2517.   Free breathing three-dimensional steady-state free procession (SSFP) non-contrast enhanced coronary magnetic resonance angiography at 3T: comparison to gradient-echo sequence
Yuki Ohmoto-Sekine1, Junji Takahashi2, Kei Fukuzawa2, Atsushi Takemura3, Hiroshi Tsuji1, and Yasuji Arase1
1Health Management Center, Toranomon Hospital, Tokyo, Japan, 2Radiology Dept., Toranomon Hospital, Tokyo, Japan, 3Philips Electronics Japan, Tokyo, Japan

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

 
2518.   Time-Resolved Non-Contrast Fresh Blood Imaging MRA Using Compressed Sensing Reconstruction
Cheng Ouyang1, Aiming Lu1, Xiangzhi Zhou1, and Mitsue Miyazaki1
1Toshiba Medical Research Institute USA, Vernon Hills, IL, United States

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

 
2519.   Optimized Fast Simultaneous Non-contrast Angiography and intraPlaque hemorrhage (fSNAP) imaging for intracranial arteries
Jia Ning1, Shuo Chen1, Jinnan Wang2,3, Xihai Zhao1, Chun Yuan1,2, and Huijun Chen1
1Center for Biomedical Imaging Research & Department of Biomedical Engineering, Tsinghua University, Beijing, China, 2Department of radiology, University of Washington, Seattle, WA, United States, 3Philips Research North America, United States

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

 
2520.   Inversion-Recovery-Prepared Sliding Interleaved Cylinder (SLINCY) Imaging
Kie Tae Kwon1, Bob S Hu2, and Dwight G Nishimura1
1Electrical Engineering, Stanford University, Stanford, CA, United States, 2Palo Alto Medical Foundation, Palo Alto, CA, United States

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

 
2521.   Nonenhanced Evaluation of the Peripheral Arteries using Quiescent-Inflow Single-Shot with Arterial Spin Labeling (QISS ASL) MR Angiography
Robert R. Edelman1,2, Oisin Flanagan2, Shivraman Giri3, and Ioannis Koktzoglou1,4
1Radiology, NorthShore University HealthSystem, Evanston, IL, United States, 2Radiology, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States, 3Siemens Healthcare, Chicago, IL, United States, 4Radiology, University of Chicago Pritzker School of Medicine, Chicago, IL, United States

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

 
 

TRADITIONAL POSTER SESSION ○ CARDIOVASCULAR
Vessel Wall Imaging & Emerging Technologies

 
Wednesday 14 May 2014
Traditional Poster Hall  13:30 - 15:30

2522.   3D coronary dark-blood interleaved with gray-blood (cDIG) MRI
Guoxi Xie1,2, Bin Sun3, Qingyi Dai4, Antonio Hernandez Conte2, Xiaoming Bi5, Yutaka Natsuaki5, Jing An6, Reza Arsanjani2, Xin Liu1, Hairong Zheng1, Zhanming Fan4, Daniel Berman2, Debiao Li2, and Zhaoyang Fan2
1Shenzhen Key Lab for MRI, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China, 2Cedars Sinai Medical Center, Los Angeles, CA, United States, 3Union Hospital, Fujian Medical University, Fujian, China, 4Radiology Department, Anzhen Hospital, Beijing, China, 5Siemens Healthcare, Los Angeles, CA, United States, 6MR Collaborations NE Asia, Siemens Healthcare, Beijing, China

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

 
2523.   Optimized threshold selection for automatic carotid intraplaque hemorrhage detection in magnetization-prepared rapid acquisition gradient-echo (MP-RAGE) MRI with histology validation
Jin Liu1, Niranjan Balu1, Daniel S. Hippe1, Marina S. Ferguson1, Vanesa Martinez-Malo1, J. Kevin DeMarco2, David C. Zhu2, Hideki Ota3, Jie Sun1, William S. Kerwin1, Thomas S. Hatsukami1, and Chun Yuan1
1University of Washington, Seattle, WA, United States, 2Michigan State University, MI, United States, 3Tohoku University Hospital, Sendai, Japan

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

 
2524.   Black-blood vessel wall imaging using SLR designed velocity selective RF pulse
Yunduo Li1, Lirong Yan2, Mayank Jog2, Robert Smith2, Karen Ying3, Rui Li4, Chun Yuan4, and Danny JJ Wang2
1Department of Biomedical Engineering, Tsinghua University, Beijing, Beijing, China, 2Neurology, UCLA, CA, United States, 3Department of Engineering Physics, Tsinghua University, Beijing, China, 4Center for Biomedical Imaging Research, Tsinghua University, Beijing, China

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

 
2525.   Inhomogeneity Insensitive MSDE (i2MSDE)
Jinnan Wang1, Michael Schär2, Chun Yuan3, and Peter Börnert4
1Philips Research North America, Seattle, WA, United States, 2Philips Healthcare, Cleveland, Ohio, United States, 3University of Washington, Seattle, WA, United States, 4Philips Research Europe, Hamburg, Hamburg, Germany

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

 
2526.   Optimized Fast Simultaneous Non-contrast Angiography and intraPlaque hemorrhage (fSNAP) Imaging with low-resolution reference scan for Carotid Artery
Shuo Chen1, Xihai Zhao1, Jia Ning1, Jinnan Wang2,3, Chun Yuan1,2, and Huijun Chen1
1Center for Biomedical Imaging Research & Department of Biomedical Engineering, School of Medicine, Beijing, China, 2Department of radiology, University of Washington, Seattle, WA, United States, 3Philips Research North America, Briarcliff Manor, NY, United States

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

 
2527.   Feasibility of Simultaneous Non-contrast Angiography and intraPlaque hemorrhage (SNAP) in Femoral Artery Imaging
Shuo Chen1, Xihai Zhao1, Jinnan Wang2,3, Chun Yuan1,2, and Huijun Chen1
1Center for Biomedical Imaging Research & Department of Biomedical Engineering, School of Medicine, Beijing, China, 2Department of radiology, University of Washington, Seattle, WA, United States, 3Philips Research North America, Briarcliff Manor, NY, United States

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

 
2528.   Using 3T MRI To Characterize The Early Lesion Of Carotid Vessel Wall In Systemic Lupus Erythematosus Patients With Subclinical Atherosclerosis.
Wei Zhang1, Jie Sun2, Bin Zhou1, Jianrong Xu1, Daniel S Hippe2, Thomas S Hatsukami2, and Chun Yuan2
1Department of Radiology, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, Shanghai, China, 2Department of Radiology, University of Washington, Seattle, WA, United States

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

 
2529.   Dual Contrast Vessel Wall MRI using Phase Sensitive Polarity Maps
Niranjan Balu1, Haining Liu1, Shuo Chen2, Huijun Chen2, Jinnan Wang3, Zechen Zhou1, and Chun Yuan1
1Radiology, University of Washington, Seattle, WA, United States, 2Biomedical Engineering, School of Medicine,Tsinghua University, Beijing, China, 3Philips Research North America, Briarcliff Manor, New York, United States

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

 
2530.   Vessel Wall Changes In Patients With Systemic Lupus Erythematosus Compared To Controls: A Preliminary MR Imaging Study In Carotid Artery
Wei Zhang1, Jie Sun2, Bin Zhou1, Jianrong Xu1, Daniel S Hippe2, Huijun Chen3, Thomas S Hatsukami2, and Chun Yuan2
1Department of Radiology, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, Shanghai, China, 2Department of Radiology, University of Washington, Seattle, WA, United States, 3Department of Biomedical Engineering, Tsinghua University, Beijing, China

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

 
2531.   Voxel anisotropy in carotid MRI: impact on fibrous cap thickness and lipid-rich necrotic core size measurements of atherosclerotic plaques
Harm Nieuwstadt1, Zaid Kassar1,2, Aad van der Lugt2, Ton van der Steen1,3, Marcel Breeuwer4,5, and Frank Gijsen1
1Biomedical Engineering, Erasmus MC, Rotterdam, Zuid-Holland, Netherlands, 2Radiology, Erasmus MC, Rotterdam, Zuid-Holland, Netherlands, 3Imaging Science and Technology, Delft University of Technology, Delft, Zuid-Holland, Netherlands, 4Philips Healthcare, Best, Noord Brabant, Netherlands, 5Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Noord Brabant, Netherlands

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

 
2532.   Time-efficient Diffusion-weighted Black Blood Imaging Based on iMSDE
Haining Liu1, Zechen Zhou2, Jinnan Wang3, Shuo Chen2, Balu Niranjan4, and Chun Yuan2,4
1Bioengineering Department, University of Washington, Seattle, WA, United States, 2Bioengineering Department, Tsinghua University, Beijing, China, 3Philips Research North America, NY, United States, 4Radiology Department, University of Washington, WA, United States

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

 
2533.   Quantification of Aortic Stiffness across the Cardiac Cycle Using Magnetic Resonance Elastography: Reproducibility Study
Anirudh Damughatla1, William Kenyhercz2, Brian Raterman2, Peter Wassenaar2, Richard White1,3, and Arunark Kolipaka1,3
1Biomedical Engineering, The Ohio State University, Columbus, Ohio, United States, 2Radiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, United States, 3Radiology and Internal Medicine, Division of Cardiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, United States

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

 
2534.   High-resolution multi-parametric characterization of atherosclerotic lesions with 3T intravascular MRI
Guan Wang1,2, M. Arcan Erturk1,2, Shashank Sathyanarayana Hegde2, and Paul A. Bottomley1,2
1Electrical & Computer Engineering, Johns Hopkins University, Baltimore, MD, United States, 2Russell H. Morgan Dept. of Radiology & Radiological Sciences, Johns Hopkins University, Baltimore, MD, United States

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

 
2535.   High temporal resolution Black Blood Vessel Wall Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI) using fast imaging methods
Xiaoying Cai1, Feng Huang2, Tingting Wu3, Kui Ying4, Chun Yuan3, and Huijun Chen3
1Biomedical Engineering, University of Virginia, Charlottesville, Virginia, United States, 2Philips Healthcare, Gainesville, FL, United States, 3Center for Biomedical Imaging Research, Beijing, China, 4Department of Engineering Physics, Tsinghua University, Beijing, China

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

 
2536.   Fast 3D isotropic high spatial resolution MRI of peripheral vessel wall at 3T
Guoxi Xie1,2, Xiaoming Bi3, Jing An4, Xin Liu1, Hairong Zheng1, Debiao Li2, and Zhaoyang Fan2
1Shenzhen Key Lab for MRI, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China, 2Biomedical Imaging Research Institute, Cedars Sinai Medical Center, Los Angeles, CA, United States, 3Siemens Healthcare, Los Angeles, CA, United States, 4MR Collaborations NE Asia, Siemens Healthcare, Beijing, China

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

 
2537.   Is automatic analysis of multicontrast MRI ready for clinical studies on plaque tissue composition?
Taku Yoneyama1, Jie Sun1, Daniel Hippe1, Dongxiang Xu1, William Kerwin1, Thomas Hatsukami1, and Chun Yuan1
1University of Washington, Seattle, WA, United States

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

 
2538.   2D and 3D multi-contrast black blood carotid vessel wall imaging applying DANTE preparation
Chengcheng Zhu1, Andrew J Patterson1, Jonathan H Gillard1, and Martin J Graves1
1Department of Radiology, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom

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

 
2539.   Optimized Dark-Blood Imaging for Evaluation of the Aorta and Subclavian Arteries in Patients with Giant Cell Arteritis
Iulius Dragonu1, Julia Geiger2, Bernd Jung1, Marco Vicari1, Jürgen Hennig1, and Ute Ludwig1
1Radiology - Medical Physics, University Medical Center Freiburg, Freiburg, Germany, 2Radiology, University Medical Center Freiburg, Freiburg, Germany

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

 
2540.   Hemodynamic Abnormalities Reflected by Low Diastolic Wall Shear Stress and High OSI as Potential Determinants of Lower Abdominal Aortic Atherosclerosis
Masataka Sugiyama1, Yasuo Takehara1, Yang Wang1, Shuhei Yamashita1, Naoki Ooishi1, Marcus Alley2, Tetsuya Wakayama3, Atsushi Nozaki3, Hiroyuki Kabasawa3, and Harumi Sakahara1
1Radiology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan, 2Radiology, Stanford Unviersity School of Medicine, Palo Alto, CA, United States, 3Applied Science Laboratory Asia Pacific, GE Healthcare Japan, Hino, Tokyo, Japan

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

 
2541.   Ultrahigh-field quantitative MR imaging of ex vivo intracranial atherosclerotic plaques
Anita A. Harteveld1, Nerissa P. Denswil2, Jeroen C.W. Siero1, Jaco J.M. Zwanenburg1,3, Aryan Vink4, Wim G.M. Spliet4, Nikki Dieleman1, Peter R. Luijten1, Mat J.A.P. Daemen2, Jeroen Hendrikse1, and Anja G. van der Kolk1
1Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands, 2Department of Pathology, Academic Medical Center, Amsterdam, Netherlands, 3Image Science Institute, University Medical Center Utrecht, Utrecht, Netherlands, 4Department of Pathology, University Medical Center Utrecht, Utrecht, Netherlands

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

 
2542.   Contrast enhanced carotid vessel wall imaging using DANTE preparation
Chengcheng Zhu1, Andrew J Patterson1, Jonathan H Gillard1, and Martin J Graves1
1Department of Radiology, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom

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

 
2543.   A 20 channel head/neck array for three dimensional arterial wall imaging at 3T
Xiaoqing Hu1,2, Lei Zhang1, Huabin Zhu3, Xiao Chen1, Yiu-cho Chung1,2, Xin Liu1,2, Hairong Zheng1,2, and Ye Li1,2
1Shenzhen Institutes of Advanced Technology of Chinese Academy of Sciences, Shenzhen, Guangdong, China, 2Shenzhen Key Laboratory for MRI, Shenzhen, Guangdong, China, 3Suzhou Medcoil Healthcare Co.,Ltd, Suzhou, Jiangsu, China

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

 
2544.   The detection of the stenotic lesion in proximal internal carotid artery using black blood imaging with CUBE T1 in comparison of MRA with 3D TOF.
Kei Tsukamoto1, Takayuki Masui1, Motoyuki Katayama1, Kimihiko Satoh1, Kenichi Mizuki1, Masayoshi Sugimura1, Harumi Sakahara2, Mitsuharu Miyoshi3, and Hiroyuki Kabasawa3
1Seirei Hamamatsu General Hospital, Hamamatsu, Shizuoka, Japan, 2Hamamatsu Universtiy of Medicine, Hamamatsu, Shizuoka, Japan, 3GE Health Care Japan, Hino, Tokyo, Japan

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

 
2545.   Dynamic contrast enhanced imaging transit times are independently associated with RV volume and invasive prognostic markers in pulmonary hypertension
Andrew Swift1, Dave Capener2, Helen Marshall2, Charlie Elliot3, Robin Condliffe3, David Kiely3, and Jim Wild2
1Academic Unit of Radiology, University of Sheffield, Sheffield, S.Yorkshire, United Kingdom, 2Academic Unit of Radiology, University of Sheffield, S.Yorkshire, United Kingdom,3Sheffield Pulmonary Vascular Disease Unit, Sheffield Teaching Hospitals NHS Trust, S.Yorkshire, United Kingdom

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

 
2546.   Feasibility of volume pulsation measurements of intracranial aneurysms using high-resolution 7T MRI images.
Bram Schermers, BSc1,2, Rachel Kleinloog, MD1, Bon H Verweij, MD, PhD1, Ynte M Ruigrok, MD, PhD1, Peter R Luijten, PhD3, Fredy Visser3,4, Luca Regli, MD, PhD1,5, Gabriël JE Rinkel, MD1, and Jaco J Zwanenburg, PhD3
1Brain Center Rudolf Magnus, Department of Neurology and Neurosurgery, University Medical Center Utrecht, Utrecht, Utrecht, Netherlands, 2Faculty of Science and Technology, Department of Technical Medicine, University of Twente, Enschede, Twente, Netherlands, 3Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands, 4Philips Healthcare, Best, Netherlands, 5Department of Neurosurgery, University Hospital Zürich, Zürich, Switzerland

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

 
2547.   Probing energy metabolism in the ischemic rat heart with hyperpolarized 13C MRS
Hikari A. I. Yoshihara1,2, Jessica A. M. Bastiaansen2,3, Corinne Berthonneche4, Arnaud Comment2,3, and Juerg Schwitter5
1Division of Cardiology, Lausanne University Hospital, Lausanne, Switzerland, 2Center for Biomedical Imaging (CIBM), Lausanne, Switzerland, 3Institute of Physics of Biological Systems, Ecole Polytechnique Fédérale de Lausanne, Switzerland, 4Cardiovascular Assessment Facility, Lausanne University Hospital, Switzerland, 5Division of Cardiology and Cardiac MR Center, Lausanne University Hospital, Switzerland

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

 
2548.   Determination of trigger delays for strain independent cardiac diffusion measurements based on automated segmentation of cine images
Peter Speier1, Andreas Greiser1, Christoph Guetter2, and Marie-Pierre Jolly2
1Siemens AG Healthcare Sector, Erlangen, Germany, 2Imaging and Computer Vision, Siemens Corporation, Corporate Technology, Princeton, NJ, United States

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

 
2549.   Comparison of 3DQRS and VCG Approaches for MR Gating in 1.5T, 3T & 7T MRIs
T. Stan Gregory1, Ehud J Schmidt2, Shelley Hualei Zhang2, and Zion Tsz Ho Tse1
1University of Georgia, Athens, GA, United States, 2Brigham and Women's Hospital, Boston, MA, United States

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

 
2550.   Black Blood CINE Imaging of Common Carotid Artery
Erpeng Dai1, Zhe Zhang1, Juan Wei2, Xihai Zhao1, Li Dong3, Chun Yuan1,4, and Hua Guo1
1Center for Biomedical Imaging Research, Tsinghua University, Beijing, Beijing, China, 2Philips Research China, Beijing, China, 3Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, Beijing, China, 4Department of Radiology, University of Washington, Seattle, WA, United States

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

 
2551.   MRI Evaluation of Coronary Versus Systemic Endothelial Function in Healthy Subjects and Patients with Coronary Artery Disease
Rupa Krishnaswamy1, Gary Gerstenblith1, Sahar Soleimanifard2, Michael Schar3, Matthias Stuber4, and Robert G Weiss5
1Medicine, Johns Hopkins University, Baltimore, MD, United States, 2Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States, 3Radiology, Johns Hopkins University, Baltimore, MD, United States, 4Radiology, Centre Hospitalier Univ Vaudois, Lausanne, Switzerland, Switzerland, 5Medicine, Radiology, Johns Hopkins Univ, MD, United States

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

 
2552.   A comparison of two sequences for spectral imaging of 19F-containing emulsions
Rik PM Moonen1,2, Gustav J Strijkers1,2, Abdallah Motaal1,2, Rolf Lamerichs2,3, Muhammed Yildirim4, Erica Aussems-Custers2,3, Holger Gruell1,3, Martijn Wolters5, Eline ME Kooi5, Christoph Jacoby6, Ulrich Flögel6, and Klaas Nicolay1,2
1Biomedical Engineering/Biomedical NMR, Eindhoven University of Technology, Eindhoven, Netherlands, 2Center for Imaging Research & Education (CIRE), Eindhoven, Netherlands, 3Philips Research, Eindhoven, Netherlands, 4Philips Healthcare, Best, Netherlands, 5Department of Radiology, Maastricht University Medical Center (MUMC+), Maastricht, Netherlands, 6Institut für Molekulare Kardiologie, Heinrich-Heine-Universität, Düsseldorf, Germany

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