Electronic Posters : Cardiovascular Imaging
Click on to view the abstract pdf and click on to view the video presentation.
Cardiovascular Image Processing & Flow Quantification

Monday May 9th
Exhibition Hall  14:00 - 16:00 Computer 31

14:00 3273.   Evaluation of Vessel Area using Time-of-Flight MR Angiography, Contrast-Enhanced MR Angiography and CT Angiography in a Rabbit Peripheral Arterial Disease Model  
YI XU1, Yingli Fu1, Nicole Azene1, Dorota Kedziorek1, Tina Ehtiati2, Aaron Flammang2, Bruce A Wasserman1, Ye Qiao1, Merine Etesami1, Steven M Shea2, and Dara L Kraitchman1
1Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, United States, 2Center for Applied Medical Imaging, Siemens Corporate Research, Inc., Baltimore, Maryland, United States

Measurement of small vessel diameters by MRA is challenging especially in ischemic disease. Our purpose was to compare vessel area measurement by TOF-MRA, ce-MRA and CTA after transplantation of mesenchymal stem cells in an animal peripheral arterial disease model. Both MRA techniques could provide an acceptable precision to measure small vessel diameters without ionizing radiation for the evaluation of an arteriogenesis therapy efficiacy.

14:30 3274.   Wavelet denoising of first-pass perfusion: impact on visual assessment. 
Pedro Ferreira1, Peter Gatehouse2, Tevfik Ismail2, Ankur Gulati2, and David Firmin2
1Imperial College, London, London, United Kingdom, 2Royal Brompton Hospital

In this work two experienced observers evaluate in a blind score, the impact in diagnostic confidence of wavelet denoising, in a visual assessment of first-pass myocardial perfusion in a cohort of hypertrophied cardiomyopathy patients. Initial results show that wavelet denoising seems to be detrimental for diagnostic confidence. Both observers criticized the increase in blur resulting from the denoising process, with one observer scoring a lower diagnostic confidence for the denoised data (p < 0.05).

15:00 3275.   Abnormal Right Heart Flow Patterns in Pulmonary Artery Hypertension Visualized with 4D Flow-Sensitive MRI 
Christopher J François1, Alejandro Roldan1, Eric Niespodzany2, Naomi C Chesler3, Jonathan G Keevil4, and Alex P Frydrychowicz1
1Radiology, University of Wisconsin, Madison, WI, United States, 2Medical Physics, University of Wisconsin, Madison, WI, United States, 3Biomedical Engineering, University of Wisconsin, Madison, WI, United States, 4Medicine, University of Wisconsin, Madison, WI, United States

Flow patterns in the right atrium, right ventricle and central pulmonary arteries, visualized with four-dimensional, flow-sensitive phase-contrast MRI, are dramatically different from those in normal, healthy volunteers. Analysis of these altered flow patterns may provide a better understanding of the interactions between pulmonary artery hypertension and right heart failure.

15:30 3276.   Automated Segmentation of Myocardial Infarcts on Delayed Enhancement MR Images 
YingLi Lu1, Graham A. Wright1,2, and Perry E. Radau1
1Imaging Research, Sunnybrook Health Science Centre, Toronto, ON, Canada, 2Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada

A novel, accurate and automatic algorithm is presented for segmenting myocardial infarcts from cardiac delayed enhancement MR images. The algorithm begins by localizing the LV center on a mid-ventricular slice by roundness metric. Then a bilateral filter is applied to smooth the image while preserving the edges. Next a tophat morphological transformation is used to isolate brighter objects. Finally a threshold is applied to determine the infarct. The correlation and Bland-Altman analysis of the infarct size derived from automatic and manual quantification indicated high correlations and good agreement.

Tuesday May 10th
  13:30 - 15:30 Computer 31

13:30 3277.   Automated Extraction of the Arterial Input Function from Contrast-Enhanced First-Pass Cardiac MR Perfusion Images 
Li-Yueh Hsu1, Mikhail Gorbachev1,2, Lin-Ching Chang2, Sujethra Vasu1, Christine Mancini1, W Patricia Bandettini1, and Andrew E Arai1
1National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, United States, 2Department of Electrical Engineering and Computer Science, The Catholic University of America, Washington, D.C., United States

Myocardial blood flow can be estimated from the time-signal intensity curves of the left-ventricular (LV) blood cavity and the myocardium of the contrast-enhanced first-pass CMR perfusion images. The aim of this study is to develop a fully automated computer method to extract the arterial input function (AIF) from the LV cavity of the CMR perfusion images. The method was applied to 176 perfusion image series and compared with a reference standard AIF as defined by manual tracing. The results show a close match between computer and manual extracted AIF.

14:00 3278.   Inline Myocardial T2* Mapping with Iterative Robust Fitting 
Saurabh Shah1, Hui Xue2, Andreas Greiser3, Peter Weale1, Taigang He4, David N Firmin4, Dudley J Pennell4, Sven Zühlsdorff1, and Jens Guehring3
1Siemens Healthcare, Chicago, IL, United States, 2Siemens Corporate Research, Princeton, NJ, United States, 3Siemens AG, Erlangen, Germany, 4Royal Brompton Hospital, London, United Kingdom

Myocardial T2* estimation using cardiac MRI is a valuable tool for non-invasive assessment of iron overload. In this study, a T2* measurement technique with automated inline T2* map generation is developed and tested in volunteers and patients with iron overload.

14:30 3279.   A New Triangulated Surface Approach to Measuring Apex Curvature from Cine MRI in Patients with Mitral Regurgitation 
Chun Guo Schiros1, Steven G Lloyd2, Himanshu Gupta2, Louis J. Dell'Italia2, and Thomas S. Denney Jr.3
1Electrical and Computer Engineering Department, Auburn University, Auburn, AL, United States, 2University of Alabama at Birmingham, 3Auburn University

A new surface modeling technique based on triangulated surface was presented to model all levels of the left ventricle including apex. A Bspline surface model based on prolate spheroidal coordinate system was used as a gold standard for validation. Correlation analysis and Bland-Altman plots on circumferential curvatures show the triangulated surface method has good agreement with the gold standard at base and near apex. Comparison of apex maximum curvatures measured by the triangulated surface in 40 normals and 21 patients with moderate chronic, compensated mitral regurgitation (MR) show apex maximum curvatures in MR hearts are significantly lower than in normals.

15:00 3280.   A Geometric Method Based on Mass Center Drifting Detection for Improving Basal Left Ventricle Automated Segmentation 
Mengchao Pei1, Lijia Wang1,2, Jianqi Li1, Mingxia Fan1, and Yi Wang2,3
1Shanghai Key laboratory of Magnetic Resonance, East China Normal University, Shanghai, Shanghai, China, People's Republic of, 2Department of Radiology, Weill Medical College of Cornell University, New York, NY, United States, 3Department of Physiology, Biophysics, and Systems Biology, Weill Medical College of Cornell Universi, New York, NY, United States

To improve accuracy and robustness of automated left ventricle segmentation on short-axis cardiac MRI, a novel geometric method was proposed to define basal cardiac ventricle slices and effectively correct automated segmentation at basal ventricle slices compared to previous approaches. Cardiac short cine SSFP data from 30 patients were analyzed with IRB approval and HIPAA compliance. Among the 30 patients data, the success rates of identifying and correcting erroneous effusion at basal ventricle slices were 100.0% and 89.9% respectively. Automated quantification of corrected left basal ventricle slice volumes was well agreed with manual tracing measurement (0.24¡À1.09mL, R² = 0.9646). Ejection fraction calculations with this automated segmentation method were highly correlated with manual tracing measurement (0.3¡À2.7%, R² = 0.946). This approach is promising for fully automated accurate segmentation of the left ventricle blood.

Wednesday May 11th
  13:30 - 15:30 Computer 31

13:30 3281.   Algorithmic Quantification of Left Ventricle Segmentation in 4D Cardiac Magnetic Resonance Imaging based on Spatio-temporal Continuity 
Lijia Wang1,2, Mengchao Pei1, Noel C. F. Codella3, Jonathan W. Weinsaft2,4, Martin R. Prince2, and Yi Wang2,3
1Shanghai Key laboratory of Magnetic Resonance, East China Normal University, Shanghai, China, People's Republic of, 2Department of Radiology, Weill Medical College of Cornell University, New York, NY, United States, 3Department of Physiology, Biophysics, and Systems Biology, Weill Medical College of Cornell Universi, New York, NY, United States, 4Department of Medicine-Cardiology, Weill Medical College of Cornell University, New York, NY, United States

To reduce the intra- & inter- variabilities of manual intervention in left ventricle (LV) segmentation, an algorithmic LV segmentation method is proposed to select apical and basal LV positions based on spatio-temporal continuity of LV area and shape, enabling segment the entire LV at all the cardiac phases. This algorithm was validated on short axis cine SSFP data from 38 patients with IRB approval and HIPAA compliance by comparing with manual tracing, showing promise for rapid and accurate LV segmentation in routine clinical cardiac MRI.

14:00 3282.   Accuracy of vessel area assessment: comparison between experts and automatic FWHM 
Maarten A. G. Merkx1, Javier Oliván Bescós2, Liesbeth Geerts3, E. M. H. Bosboom1, F. N. van de Vosse4, and M. Breeuwer2,4
1Biomedical Engineering, Maastricht University Medical Center, Maastricht, Netherlands, 2Clinical Science and Advanced Development, Philips Healthcare, Netherlands, 3MR Clinical Science, Philips Healthcare, Netherlands, 4Biomedical Engineering, University of Technology Eindhoven, Netherlands

In this study, the accuracy and precision of vessel area assessment is compared between experts and an automatic full-width at half-maximum method. Both phantom and clinical data is assessed by these two approaches. The experts had fixed display settings and used caliper and contour measurement tools to obtain the vessel cross-sectional area on a predefined location. Our results indicate that the automatic method outperforms the experts on accuracy and precision in the phantom data. The contour measurements are more accurate than the caliper measurements. For the clinical data, the agreement between users and automatic method increases with increasing vessel diameter.

14:30 3283.   An Automated Method for Extraction of Tissue Doppler Like Myocardial Motion Parameters from Conventional Cine Cardiac MR - A Feasibility Study 
Peter Weale1, Christoph Guetter2, Jeremy D Collins3, Marie Wasielewski3, Neil Chatterjee4, Marie-Pierre Jolly2, Hui Xue2, Lu Xiaoguang2, Jens Guehring5, Sven Zuehlsdorff1, and James Carr3
1Cardiovascular MR Research and Development, Siemens Healthcare USA, Chicago, IL, United States, 2Siemens Corporate Research, Princeton, NJ, United States,3Radiology, Northwestern University, Chicago, IL, United States, 4Feinberg School of Medicine, Northwestern University, Chicago, IL, United States, 5Magnetic Resonance, Siemens AG, Healthcare Sector, Erlangen, Germany

Tissue Doppler Imaging is an increasingly important echo-cardiographic method whereby mitral annulus velocity parameters such as early diastolic relaxation (e prime) and motion due to atrial contraction (a prime) are used in the assessment of diastolic function. A novel use of a fully automated feature tracking algorithm to identify and track the mitral annulus on conventional four-chamber cine MR images of the heart and subsequently to extract the mitral annular velocity from which the corresponding e-prime values are derived is described. The method allows fully automated extraction of mitral annular functional parameters, from routinely acquired cardiac imaging protocols.

15:00 3284.   4D Gradient Based Phase Unwrapping for PC-MR Flow Data 
Michael Loecher1, Kevin Johnson1, Benjamin Landgraf1, and Oliver Wieben1,2
1Medical Physics, University of Wisconsin, Madison, WI, United States, 2Radiology, University of Wisconsin, Madison, WI, United States

4D PC MRI has emerged as a promising approach for hemodynamic evaluation of larger vascular territories. One of the major problems associated with volumetric phase contrast MRI is the large dynamic range of velocities of interest and the potential risk of velocity aliasing in areas of higher velocities. This work describes an algorithm that minimizes local gradients in 4 dimensions within vessels to detect and correct phase wrapped voxels. This method is strengthened by the use of PC-VIPR, allowing for small voxel sizes and high temporal resolution. The algorithm is generally successful as long as wrapping stays below certain levels.

Thursday May 12th
  13:30 - 15:30 Computer 31

13:30 3285.   Rapid 3D in vivo Magnetic Particle Imaging with a Large Field of View 
Jürgen Rahmer1, Bernhard Gleich1, Claas Bontus1, Ingo Schmale1, Joachim Schmidt1, Jürgen Kanzenbach1, Oliver Woywode2, Jürgen Weizenecker3, and Jörn Borgert1
1Philips Research Laboratories, Hamburg, Germany, 2Philips Medical Systems DMC GmbH, Hamburg, Germany, 3University of Applied Sciences, Karlsruhe, Germany

Magnetic particle imaging (MPI) is a new tomographic imaging approach that quantitatively maps concentrations of iron oxide nanoparticle distributions. It combines high sensitivity with the ability of fast volumetric imaging. In vivo 3D real-time MPI of a bolus of particles flowing through the heart and lung of mice has been demonstrated before, but with an imaging approach that is limited to small fields of view. Recently, a new scanner type with a bore diameter of 12 cm allowing rapid imaging with larger FoVs has been developed. This contribution presents initial in vivo rat measurements on the new system, demonstrating real-time imaging on a small volume covering the heart as well as slower imaging on a larger volume.

14:00 3286.   Flow Quantification with 4D Flow-Sensitive MRI: Validation in Patients with Congenital Heart Disease 
Christina Boncyk1, Alex P Frydrychowicz1, Michael W Loecher2, Elizabeth J Nett2, Benjamin R Landgraf1, Kevin M Johnson2, Oliver Wieben1,2, and Christopher J François1
1Radiology, University of Wisconsin, Madison, WI, United States, 2Medical Physics, University of Wisconsin, Madison, WI, United States

Flow quantification with MRI in patients with congenital heart disease (CHD) is frequently difficult to perform and time consuming because of the complex anatomy. 4D flow-sensitive phase contrast (PC) MRI has the potential to simplify the acquisition and quantification of flow information in patients with CHD. In this study we compared flow measurements through the aorta and main pulmonary artery in patients with CHD with a 3D radially undersampled, 3D PC MRI technique to standard 2D PC and 2D bSSFP measurements.

14:30 3287.   K-t-GRAPPA accelerated Phase Contrast MRI: Improved assessment of blood flow and 3-directional myocardial motion during breath-hold 
Simon Bauer1, Michael Markl1, and Bernd André Jung1
1Dept. of Radiology, Medical Physics, University Medical Center, Freiburg, Germany

The use of spatiotemporal parallel imaging such as k-t-GRAPPA offers a high potential to speed-up data acquisition in dynamic imaging compared to conventional parallel imaging. In this study, velocity encoded phase-contrast MRI for the assessment of blood flow and myocardial motion was acquired during breath-hold as well as during free-breathing with navigator respiration control with a k-t-GRAPPA based technique with a reduction factor of R=5. These data were compared to an acquisition during free-breathing using conventional GRAPPA with R=2 whose lower reduction factor did not allow to acquire a high temporal resolution scan during a breath-hold period.

15:00 3288.   Stenosis Flow: Comparison of a Generalized Navier-Stokes Model and Phase Contrast MRI 
Alex J Barker1, Jelena Bock1, and Michael Markl1
1Medical Physics, Dept. of Radiology, University Medical Center Freiburg, Freiburg, Germany

The elevated velocities and accelerations present in stenosis flow phantoms replicate abnormal flow conditions present in a number of valvular and vascular pathologies. These conditions prove ideal for flow-sensitive sequence development and artifact characterization. However, it is difficult and time consuming to obtain velocity field ground truths, often requiring the implementation of CFD. Thus, a flexible integral-energy generalization of the Navier-Stokes equations is presented and compared to MR measurements. This framework provides a method to obtain stenosis velocity fields in which the flexible inputs are geometry, viscosity, and flow rate.

Electronic Posters : Cardiovascular Imaging
Click on to view the abstract pdf and click on to view the video presentation.
Flow Quantification & Venal Function

Monday May 9th
Exhibition Hall  14:00 - 16:00 Computer 32

14:00 3289.   Middle Cerebral Artery Blood Flow Velocity Changes in Response to Precise Targeting of End-Tidal CO2 and O2: A Comparative Study Between Transcranial Doppler Ultrasound and Phase Contrast Magnetic Resonance Angiography 
Jackie Leung1, Arun Mohanta1, Amir Behpour1,2, Neil Sokol2, and Andrea Kassner1,2
1Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario, Canada, 2Medical Imaging, University of Toronto, Toronto, Ontario, Canada

Transcranial Doppler ultrasonography (TCD) and phase contrast MR angiography (PCMRA) are both capable of assessing cerebral blood flow velocity changes in response to a vasoactive stimulus. TCD is widely used because it is inexpensive and accessible, despite concerns about measurement variability. PCMRA does not have such limitations. However, previous attempts to correlate TCD and PCMRA readings in the brain have produced inconsistent results. We propose to utilize a reproducible CO2 stimulus with precise end-tidal PCO2 and PO2 targeting to compare blood flow velocities changes in the middle cerebral artery using both modalities.

14:30 3290.   Hemodynamic Assessment of Kinking vs. Non-kinking Abdominal Aorta 
Mamoru Takahashi1, Yasuo Takehara2, Hiroyasu Takeda2, Masaki Terada3, Haruo Isoda4, Tetsuya Wakayama5, Atsushi Nozaki5, Toshiyuki Shimizu6, Marcus Alley7, Roland Bammer7, Norihiko Siiya2, Norihiro Tooyama8, Katsutoshi Ichijo8, and Harumi Sakahara2
1Radiology, Seirei Mikatahara General Hospital, Hamamatsu, Shizuoka, Japan, 2Hamamatsu University School of Medicine, 3Iwata City Hosipital, 4Nagoya University School of Health Sciences, 5GE Helthcare Japan, 6R's Tech Co., 7Stanford University School of Medicine, 8Seirei Mikatahara General Hospital

Hemodynamic patterns of the abdominal aorta were assessed with streamlines and pathlines, and wall shear stress was analyzed on color coded cine maps postprocessing 4D Flow data. As a result, kinking aorta suffered vortex or turbulent flow at the inner curvature of the aorta mainly during the early-diastole and this resulted in significantly low wall shear stress of the corresponding portion, while non-kinking aorta did not. Kinks of the abdominal aorta create vorticity or turbulence of the blood flow at the inner curvature of the kinking aorta,@which may have further atherogenic effect of the corresponding aortic wall.

15:00 3291.   Variable velocity encoding of 4D phase-contrast sequences to improve blood flow visualizations 
Anders Nilsson1, Karin Markenroth Bloch1,2, and Freddy Ståhlberg1,3
1Dept. of Medical Radiation Physics, Lund University, Sweden, 2Clinical Sciences, Philips Healthcare, Lund, Sweden, 3Dept. of Diagnostic Radiology, Lund University, Sweden

Conventional implementation of phase contrast sequences determines the velocity encoding sensitivity (Venc) from the maximal velocity in the complete cardiac cycle. In heart phases with slow flow, the Venc is therefore much higher than needed. By optimizing the Venc to the specific area of interest, it has been shown that the noise could be lowered substantially. In this work, we investigate the potential benefits of a 4D phase-contrast sequence with variable velocity encoding throughout the cardiac cycle, with respect to blood flow visualizations.

15:30 3292.   An in vivo MRI and computational fluid dynamic simulation of cerebrospinal fluid hydrodynamics in the third ventricle 
Aurelie Picquot1, Francesco Santini2, Jelena Bock3, Philippe Reymond1, Eleonora Fonari4, Bryn Andrew Martin1, and Nikos Stergiopulos1
1Laboratory of Hemodynamics and Cardiovascular Technology, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland, 2Radiological Physics, University of Basel Hospital, Switzerland, 3Department of Radiology, University Hospital Freiburg, Germany, 4Lausanne Center for Biomedical Imaging, Centre Hospitalier Universitaire Vaudois, Switzerland

CFD simulations have provided detailed information about the complex flow and pressure field within the cerebrospinal fluid system. The solutions of these simulations are sensitive to boundary conditions and thus need validation with in vivo measurements. However, validation of 3D CFD flow calculations and MRI CSF flow measurements have been limited to through plane pcMR velocity measurements. Recent advancements in MRI flow measurement technology have enabled fast measurement of the 3D velocity field within the spinal subarachnoid space, superior sagittal sinus, and ventricles of the brain. This study was focused on comparing the results between 3D CFD flow calculations and 7D MRI measurements within the aqueduct of Sylvius and the third ventricle of the brain.

Tuesday May 10th
  13:30 - 15:30 Computer 32

13:30 3293.   Aortic Pulse Wave Velocity Evaluation With 5-year Followup 
Yi Wang1,2, Edwin Estrada1, Visali Kodali1, and Nathaniel Reichek1,3
1Research, St. Francis Hospital, Roslyn, NY, United States, 2Biomedical Engineering, Stony Brook University, Stony Brook, NY, United States, 3Cardiology, Stony Brook University, Stony Brook, NY, United States

Aortic pulse wave velocity is altered by normal aging, as well as vessel wall pathology. We evaluated aortic compliance and its relationship to age in normals and repeated the evaluation at 5-year followup.

14:00 3294.   Volumetric Whole-Heart Three-Directional Tissue Phase Mapping of the Heart at 3T 
Anja Lutz1, Axel Bornstedt1, Patrick Etyngier2, Robert Manzke3, Wolfgang Rottbauer1, G Ulrich Nienhaus4, and Volker Rasche1
1University Hospital of Ulm, Ulm, BW, Germany, 2Medisys Research Lab, Philips Healthcare, Sureness, France, 3Philips Research NA, Briarcliff Manor, United States,4Karlsruhe Institute of Technology, Karlsruhe, Germany

Three-dimensional assessment of the myocardial contraction is gaining increasing interest e.g. for the identification of heart failure patients gaining from cardiac resynchronization therapy. For a complete understanding of the complex contraction pattern, direct velocity encoding of the myocardium appears attractive. It is the objective of this study to investigate the feasibility of volumetric whole-heart three-directional velocity encoded MRI for retrieving the complex contraction pattern of the heart. A strong variation of the radial, longitudinal and circumferential myocardial motion over different short axes regions of the heart was detected.

14:30 3295.   Aortic Flow Assessment Using Phase Contrast MRI in Mice with Aortic Regurgitation 
Xiaoli Zhang1,2, Yu Qing Zhou1, Mark van Doormaal1, and R Mark Henkelman1,2
1Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, Canada, 2Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada

Hemodynamic wall shear stress has been related to atherosclerosis development. However, the association between salient characteristics of flow patterns and localization of atherosclerotic lesions is still not fully understood. Our recent study has used surgical induction of aortic valve regurgitation to significantly change flow pattern and atherosclerotic plaques along the thoracic and abdominal aorta, which were normally lesion free. This study used a phase contrast MRI technique to elucidate blood flow in the aorta of control and AR mice. Retrograde flow during diastole was observed in the AR mouse.

15:00 3296.   Novel real-time PC-MRI technique for accurate single heartbeat evaluation of pulmonary-to-systemic flow ratios using an interleaved two-slice acquisition scheme 
Hung-Yu Lin1,2, Scott B King1, Yu Ding3, Davinder S Jassal2, Patricia Gervai1, Eilean McKenzie-Matwiy1, Orlando P Simonetti3, Boguslaw Tomanek1, and Ganghong Tian1
1Institute for Biodiagnostics, National Research Council Canada, Winnipeg, Manitoba, Canada, 2Radiology, University of Manitoba, Winnipeg, Manitoba, Canada, 3Internal Medicine, The Ohio State University, Columbus, Ohio, United States

This study is to develop and demonstrate a novel phase-contrast shared velocity encoding technique using an interleaved two-slice acquisition scheme for accurate single heartbeat evaluation of pulmonary-to-systemic flow ratio (Qp/Qs).

Wednesday May 11th
  13:30 - 15:30 Computer 32

13:30 3297.   Clinical and Cardiac Function Correlates of Aortic Pulse Wave Velocity measured by Cardiac Magnetic Resonance Imaging in Normal Subjects 
Visali Kodali1, Yi Wang1, Simcha Pollack1,2, Edwin Estrada1, and Nathaniel Reichek1,3
1Cardiac Imaging, Research, Saint Francis Hospital, Roslyn, New York, United States, 2St. John’s University, New York, New York, United States, 3Department of Biomedical Engineering Division of Cardiology, Stony Brook University, Stony Brook, New York, United States

Aortic pulse wave velocity is an index of aortic compliance. We evaluated Aortic pulse wave velocity by cardiac magnetic resonance imaging in normal volunteers and examined its relation to various clinical and cardiac function parameters. Age is the strongest and most consistent correlate of increased PWV. Coronary CT Calcium score strongly correlates with PWV. After adjustment for age, no other variables show significant associations with PWV. In normal subjects cardiac function parameters do not correlate with PWV.

14:00 3298.   Robust Data Acquisition for MR Doppler 
Daeho Lee1, Adam Bruce Kerr1, Juan Manuel Santos2, Bob Sueh-Chien Hu3, and John Mark Pauly1
1Electrical Engineering, Stanford University, Stanford, CA, United States, 2HeartVista, Inc., Palo Alto, CA, United States, 3Cardiology, Palo Alto Medical Foundation, Palo Alto, CA, United States

The pressure gradient across cardiac valves is commonly utilized to evaluate the severity of valvular stenosis. Peak velocity is often used to derive the pressure-gradient, and more accurate estimation is possible with a localized velocity spectrum. MR Doppler has been shown to effectively acquire a spatially resolved velocity spectrum in real-time without cardiac gating thanks to resolving flow along a cylindrical pathway restricted by pencil beam excitation. The fidelity of velocity estimation is especially critical for diagnosing stenotic flow in the range of 2~3 m/s. However, off-resonance, inflow effect, and flow acceleration during readout incurs signal drop and spurious dispersion in the velocity spectrum, degrading the velocity estimation. We present a circular k-space echo-shifted interleaved acquisition method to improve the reliability of velocity estimation, especially for imaging high-velocity jets.

14:30 3299.   Flow acceleration and elevated wall shear stress with hypoplastic arch after aortic coarctation repair 
Thomas A Hope1, Stephen ES Crook1, and Michael D Hope1
1Radiology, University of California San Francisco, San Francisco, CA, United States

Aneurysm formation status post aortic coarctation repair is associated with hypoplastic aortic arches. We utilized three-dimensional time resolved phase contrast MRI to demonstrate that there are abnormal systolic flow patterns that result in elevated wall shear stress in the regions of aneurysm formation in patients with hypoplastic aortic arches. These flow features may help explain the high incidence of aneurysm formation in this population as well as identify patients at high risk for aneurysm formation.

15:00 3300.   Magnetic Resonance Velocity Mapping during Intermittent Pneumatic Compression of the calf and foot 
Iain Thomas Pierce1,2, Peter David Gatehouse1,2, Evi Kalodiki3,4, Chris Lattimer3,4, George Geroulakos3,4, and David N Firmin1,2
1NHLI, Imperial College London, London, United Kingdom, 2CMR Unit, Royal Brompton Hospital Trust, London, United Kingdom, 3Dept of Surgery and Cancer, Imperial College London, London, United Kingdom, 4Vascular Unit, Ealing Hospital, London, United Kingdom

Intermittent Pneumatic Compression is commonly used as prophylaxis for venous-thromboembolism. Previously Doppler ultrasound has been used to investigate the venous flow resulting from IPC devices. Real-time MR velocity mapping, using spiral gradient readouts, was used to monitor the anatomical and velocity changes throughout multiple IPC cycles using foot and calf cuffs together and also individually. This method measured deep venous flow in 12 subjects allowing complex flow to be visualised in two subjects and measurement from secondary deep veins present in two different subjects, both of which would not be possible using ultrasound.

Thursday May 12th
  13:30 - 15:30 Computer 32

13:30 3301.   Workflow Integrated Interactive Realtime Radial Flow Measurement with Dynamic VENC Adjustment for Accurate Peak Velocity Estimation 
Peter Speier1, Andreas Greiser1, Andre de Oliveira1, Dirk Franger2, and Edgar Müller1
1Siemens AG Healthcare Sector, Erlangen, Germany, 2Freelance Software Consultant

An interactive real-time velocity encoding (venc) scout is introduced as a fast and easy way to optimize the parameters of a clinical flow measurement. The required image quality and frame rate in the phase contrast images is achieved by applying severely undersampled radial acquisition. The interactively found venc value and scan plane geometry are propagated automatically to the subsequent clinical segmented flow measurements. The method is compared against a standard segmented breath-hold venc scout.

14:00 3302.   Whole heart flow-sensitive 4D MRI in patients after repair of tetralogy of Fallot 
Julia Geiger1, Raoul Arnold2, Brigitte Stiller2, Mathias Langer1, and Michael Markl1
1Radiology and Medical Physics, University Hospital Freiburg, Freiburg, Germany, 2Pediatric Cardiology, University Hospital Freiburg, Freiburg, Germany

The aim of this study was to analyze the flow characteristics in patients after repair of tetralogy of Fallot by flow-sensitive 4D MRI. Flow acceleration, vortices and retrograde flow were successfully visualized in the pulmonary system. We detected a significant correlation between some vascular geometric parameters, particularly vessel diameter and pulmonary branching angles, and abnormal flow patterns. 4D MRI is an excellent technique to demonstrate the complexity of postoperative hemodynamics in Fallot patients.

14:30 3303.   Dual VENC Phase Contrast MRI for Simultaneous Assessment of Blood Flow and Cardiac Motion 
Waltraud Brigitte Buchenberg1, Michael Markl1, Simon Bauer1, Jelena Bock1, Ramona Lorenz1, and Bernd A. Jung1
1Radiology, Medical Physics, University Medical Centre, Freiburg, Germany

Methods to acquire the blood flow within the cardiovascular system or the myocardial motion have already been established. However, the simultaneous acquisition of this functional information requires two different velocity sensitivities (VENC) due to the different range of velocities. Therefore, a dual VENC phase contrast sequence was implemented allowing the acquisition of blood flow and cardiac motion in a single measurement and applied to five healthy volunteers.

15:00 3304.   Normal Local Pulse Wave Velocity Predicts Absence of Local Aorta Diameter Growth in Marfan Syndrome: A Comprehensive MRI-Approach 
Jos JM Westenberg1, Patrick JH de Koning1, Pieter J van den Boogaard1, Dennis Hendriksen1, Johan HC Reiber1, Albert de Roos1, and Rob J van der Geest1
1Radiology, Leiden University Medical Center, Leiden, ZH, Netherlands

In a comprehensive MRI-approach, patients with Marfan syndrome are evaluated at baseline and at two year follow up. Pulse wave velocity, assessed from two-directional velocity-encoded MRI, is locally assessed in the aorta and compared with local aortic diameter growth, assessed from contrast-enhanced MR angiography of the aorta. With this new imaging tool, normal local aortic pulse wave velocity assessed with two-directional velocity-encoded MRI predicts in 89% of the cases absence of aortic diameter growth in patients with Marfan syndrome after two years follow up.

Electronic Posters : Cardiovascular Imaging
Click on to view the abstract pdf and click on to view the video presentation.
Vessel Wall Imaging (Non-Coronary)

Monday May 9th
Exhibition Hall  14:00 - 16:00 Computer 33

14:00 3305.   Plaque disruption in a rabbit model of atherothrombosis occurs in regions of low endothelial shear stress 
Alkystis Phinikaridou1, Ning Hua1, and James A Hamilton1
1Department of Physiology and Biophysics, Boston University, Boston, MA, United States

Local hemodynamic factors, in particular low endothelial shear stress (ESS), have been shown to play a major role in the regional localization and progression of atherosclerosis. In this study, we have measured shear stress by in vivo MRI in a rabbit aorta with stable and vulnerable plaques. Low ESS was associated with plaques with positive arterial remodeling that disrupted after pharmacological triggering. Measurement of ESS in individuals with atherosclerotic disease might be a useful parameter for assessing plaque instability and predicting the risk of future cardiovascular events.

14:30 3306.   Evaluation of 3D Blood Flow Changes in the Normal and Dilated Thoracic Aorta using flow-sensitive 4D MRI. 
Jonas Bürk1, Zoran Stankovic1, Alex Frydrychowicz1, Mathias Langer1, and Michael Markl1
1Department of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany

Flow-sensitive 3D MRI was used to visualize different flow patterns in the thoracic aorta of 33 patients with dilated or aneurismal ascending aortae (greater or equal 40mm), 15 age matched normal controls, and 15 young healthy volunteers. Considerably enhanced incidence and strength of blood flow alterations (helix and vortex flow) in the ascending aorta in patients compared to age matched controls and young healthy volunteers were observed. Strengths of ascending aortic helix and vortex flow was directly associated with an increase in AAo diameter and AAo/DAo diameter ratio. Follow up studies are needed to correlate aneurysm growth rate or rupture risk with flow pattern alterations.

15:00 3307.   Calculation of Wall Shear Stress in Intracranial Cerebral Aneurysms Using High Resolution Phase Contrast MRA (PC-VIPR) 
Warren Chang1, Steven Kecskemeti2, Alex Frydrychowicz1, Benjamin Landgraf1, Beverly Aagaard-Kienitz1, Yijing Wu2, Kevin Johnson2, Oliver Wieben2, Charles Mistretta2, and Patrick Turski1
1Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States, 2Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States

Wall shear stress (WSS) may have prognostic value in evaluating the progression of intracranial cerebral aneurysms. Abnormal WSS values are found in areas of complex flow, leading to the growth and rupture of aneurysms. In this study, we evaluate WSS values in 6 patients with aneurysms compared to values from similar arterial segments in 10 normal volunteers. Patients with aneurysms demonstrated higher WSS values proximal to the aneurysm neck and lower WSS values inside the body of the aneurysm. This is consistent with current theories in the literature attributing high WSS to aneurysm formation and low WSS to aneurysm progression.

15:30 3308.   Carotid plaque MRI characteristics as a marker of severe coronary artery disease. 
Hideki Ota1, Minako Oikawa2, Morihiko Takeda3, Satoshi Yasuda3, Jun Takahashi3, Yoshitaka Ito3, Yoshihiro Fukumoto3, Hiroaki Shimokawa3, Shuichi Higano1,4, and Shoki Takahashi1
1Diagnostic Radiology, Tohoku University Hospital, Sendai, Miyagi, Japan, 2Sendai Red Cross Hospital, Sendai, Miyagi, Japan, 3Cardiovascular Medicine, Tohoku University Hospital, Sendai, Miyagi, Japan, 4Sendai Radiation Oncology & Imaging Clinic, Sendai, Miyagi, Japan

We evaluated whether carotid MRI plaque characteristics and/or carotid wall thickness were associated with the severity of coronary artery disease in 43 patients with effort angina. Presence of complicated American Heart Association type-VI carotid plaque was significantly associated with the higher number of diseased coronary arteries after controlling for traditional risk factors of atherosclerosis as potential confounders (adjusted OR = 4.2, 95%CI, 1.1, 16.4, p=0.037). However, carotid wall thickness was not associated (adjusted OR, 0.75, 95%CI, 0.4, 1.4, p=0.35). In this population, carotid plaque characteristics may play a more important role than carotid wall thickness in predicting mutlivessel coronary disease.

Tuesday May 10th
  13:30 - 15:30 Computer 33

13:30 3309.   Comparison of non-invasive self-gated Flash (Intragate®) with prospectively triggered Flash cine sequences for the evaluation of aortic distensibility in mice at 9.4 T. 
Peter Fries1, Roland Seidel1, Andreas Müller1, Günther Schneider1, Alexander Massmann1, and Arno Bücker1
1Clinic of Diagnostic and Interventional Radiology, Saarland University Hospital, Homburg, Saarland, Germany

To compare noninvasive self-gated (NSG)-Flash Intragate with prospectively triggered (PT)-Flash sequences for Cine imaging of the ascending aorta and the quantitative and qualitative assessment of aortic distensibility (AD) in mice at 9.4T. While both sequences provide the same qualitative data for AD, two blinded readers rated NSG-Flash as a preferable technique being less prone to flow and trigger artifacts and showing a more homogeneous depiction of the cardiac cycle. The acquisition time of NSG-Flash sequences was lower than for PT-Flash, most likely based on misregistrations of the respiratory cycle and ECG by the external monitoring device.

14:00 3310.   Improvements of suppression of in-plane flow signal of carotid arteries using phase sensitive inversion recovery -3D T1 turbo field echo 
Nao Kajihara1, Tomohiko Horie1, Masatoshi Honda1, Isao Muro1, Taro Takahara2, Hisamoto Moriguchi1, and Yutaka Imai1
1Radiology, Tokai University School of Medicine, Isehara, Kanagawa, Japan, 2Tokai University School of Engineering, Hiratsuka, Kanagawa, Japan

3D inversion recovery -T1 turbo field echo (3D IR-T1TFE) has been widely used to suppress signals from flowing blood. However, it usually does not achieve complete elimination of the signals from blood due to T1 relaxation occurred during long acquisition time. Phase sensitive IR (PSIR) has been proposed to improve detection of myocardial infarction using Gadolinium-delayed hyperenhancement. It maintains polarity of magnetization inverted by an IR RF pulse and corrects for phase error in the images. In this study, we show that improved suppression of in-plane flow signal of carotid arteries is achieved using 3D IR-T1TFE combined with PSIR.

14:30 3311.   Quantitative T1, T2 and T2* Mapping of Carotid Artery Normal Wall and Atherosclerotic Plaque 
Georgeta Mihai 1, Shivraman Giri2, Travis P Sharkey-Toppen2, Subha V Raman1, Sanjay Rajagopalan1, and Orlando P Simonetti1
1Cardiovascular Medicine, The Ohio State University, Columbus, OH, United States, 2Biomedical Engineering, The Ohio State University, Columbus, OH, United States

Identification of atherosclerosis plaque composition with MRI is based on the tissue’s specific biophysical MR properties (T1, T2, T2*,etc.). These intrinsic properties can be identified and displayed as MR quantitative relaxation time maps that have the fundamental information needed to characterize plaque morphology. This study shows that quantitative mapping of MRI relaxation times in carotid arteries of normal and diseased subjects is feasible, suggesting they have the potential to generate an objective, unbiased, quantitative approach to define atherosclerosis disease severity.

15:00 3312.   CINE Turbo Spin Echo Imaging 
Jason K Mendes1, Dennis L Parker1, and Jordan P Hulet1
1University of Utah, Salt Lake City, UT, United States

This work introduces a relatively simple method of converting a conventional TSE acquisition into a retrospectively ECG correlated cineTSE sequence. The cineTSE sequence generates a full sequence of ECG correlated images at each slice location throughout the cardiac cycle in the same scan time that is conventionally used by standard TSE sequences to produce a single image at each slice location. The cineTSE images exhibit reduced pulsatile artifacts associated with a gated sequence but without the increased scan time or associated non-constant TR effects. CineTSE can more accurately identify and allow for measurements of carotid artery plaque components by improving tissue visualization, allowing for identification and exclusion of artifacts and enhancing image quality.

Wednesday May 11th
  13:30 - 15:30 Computer 33

13:30 3313.   Quantification of morphologic and microvascular vessel wall characteristics of abdominal aortic aneurysms with MRI 
Van Lai Nguyen1,2, Geert-Willem Schurink1, Anne E. Saris2, Marianne Eline Kooi2, Walter H. Backes2, Rob J. van der Geest3, and Tim Leiner2,4
1Department of Surgery, Maastricht University Medical Center, Maastricht, Netherlands, 2Department of Radiology, Maastricht University Medical Center, Maastricht, Netherlands, 3LKEB, Leiden University Medical Center, Leiden, 4Department of Radiology, Utrecht University Medical Center, Utrecht, Utrecht, Netherlands

The pathogenesis of abdominal aortic aneurysm (AAA) and the factors leading to rupture of the AAA remain incompletely understood. At present there are no good markers that predict AAA growth rate and rupture risk in individual patients. We present a method to quantitatively analyze AAA wall components, including adventitial vasa vasorum characteristics based on (dynamic) contrast-enhanced MRI and demonstrate its potential applicability to study AAA growth over time. Aneurysm wall thickness and amount of adventitial vasa vasorum were strongly correlated with maximal AAA diameter.

14:00 3314.   3D T2-Weighted Black Blood Vessel Wall Imaging with Uniform Fat and Water Separation 
Ananth J Madhuranthakam1, Mitsuharu Miyoshi2, Robert L Greenman3, and David C Alsop3
1Global Applied Science Laboratory, GE Healthcare, Boston, MA, United States, 2Global Applied Science Laboratory, GE Healthcare, Tokyo, Japan, 3Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States

A technique is presented to produce 3D T2-weighted black blood vessel wall images with uniform fat and water separation in a single acquisition. Fat/water separation is achieved by a modified 2-point Dixon reconstruction. Black blood is achieved by the use of motion sensitized driven equilibrium (MSDE), inserted in front of a 3D FSE acquisition that uses variable refocusing flip angles. The technique was used to image carotid vessels with black blood contrast and uniform fat and water separation. Vessel wall images with and without fat suppression from the same acquisition aids in plaque characterization with perfect co-registration.

14:30 3315.   Development of comprehensive 3D evaluation of atherosclerosis in multiple vascular beds 
Venkatesh Mani1, Claudia Calcagno1, Yiucho Chung2, and Zahi A Fayad1
1Radiology, Mount Sinai School of Medicine, New York, NY, United States, 2Siemens Medical Solutions

3D dark blood MRI is quickly becoming the preferred methodology for evaluating atherosclerotic plaque burden non-invasively. Here we propose the development and optimization of a 3D vessel wall imaging protocol for multiple vascular beds in the same session using a variable flip angle SPACE sequence.

15:00 3316.   SHILO: Simultaneous High/Low spatial/temporal resolution dual-imaging acquisition for improved parameters quantification in dynamic contrast enhanced (DCE) MRI of atherosclerosis 
Claudia Calcagno1, Sarayu Ramachandran2, Venkatesh Mani2, Melanie Kotys3, Stefan Fischer3, and Zahi Adel Fayad2
1Mount Sinai School of Medicine, New York, NY, United States, 2Mount Sinai School of Medicine, 3Philips Healthcare

DCE-MRI has recently been applied to quantify and characterize atherosclerotic plaques’ neovessels as a marker of plaque inflammation and vulnerability. Despite initial encouraging results, many challenges still hinder accurate quantification of plaque neovasculature. Building upon recent technical improvements in myocardial perfusion, here we develop a novel dual-imaging sequence (SHILO, Simultaneous High Low) for DCE-MRI of atherosclerosis, thus overcoming some of the challenges of this application. In this preliminary study, we successfully demonstrated the use of SHILO for accurate AIF sampling, and adequate spatial resolution images for vessel wall acquisition in both atherosclerotic rabbits and human subjects.

Thursday May 12th
  13:30 - 15:30 Computer 33

13:30 3317.   Independent Factors Which Impact Image Quality in Carotid Vessel Wall Imaging: Implications for Multi-center Studies 
Jie Sun1, Daniel S Hippe1, Hunter R Underhill2, Yan Song3, Nan Luo3, Min Chen3, Cheng Zhou3, Thomas S Hatsukami4, and Chun Yuan1
1Radiology, University of Washington, Seattle, Washington, United States, 2Medicine, University of Washington, Seattle, Washington, United States, 3Radiology, Beijing Hospital, Beijing, China, People's Republic of, 4Surgery, University of Washington, Seattle, Washington, United States

Inconsistent image quality across subjects and imaging centers remains one of the major technical problems for carotid vessel wall imaging. This study analyzed carotid MRI scans of 80 subjects collected from two imaging centers. One site was located in the U.S. and the other was in China. We have observed consistently better image quality from the latter site in our experience. The objective of our study was to identify patient characteristics associated with image quality. In addition, we further sought to uncover potential causes of image quality disparity between imaging sites.

14:00 3318.   Gadofosveset detects endothelial dysfunction associated with atherosclerotic plaque formation and progression in mice 
Alkystis Phinikaridou1, Marcelo Andia1, and Rene Botnar1
1Imaging Sciences, King's College London, London, United Kingdom

Endothelial dysfunction promotes atherosclerosis through vasoconstriction, platelet adhesion, smooth muscle cell proliferation, and thrombogenesis. In this study, we investigated whether contrast enhanced MRI using gadofosveset, a blood pool contrast agent, could detect endothelial damage associated with plaque progression in high-fat fed apoE -/- mice. Delayed enhancement MRI and measurements of the longitudinal relaxivity, R1, showed increased and localized uptake of gadofosveset within the brachiocephalic artery in mice with more severe atherosclerosis compared to mice with less atherosclerotic burden and control animals. The uptake of gadofosveset correlated with the uptake of Evan’s Blue dye, a histological marker of vascular wall permeability and endothelium dysfunction.

14:30 3319.   Fibrous Cap and Lipid Rich Necrotic Core are Difficult to be Distinguished with Routine Image Weighting at 3T 
Rui Li1,2, Jie Sun2, Marina Ferguson2, and Chun Yuan2
1Center for Biomedical Imaging Research, Tsinghua University, Beijing, China, People's Republic of, 2University of Washington, Seattle, WA, United States

Multi-contrast vessel wall imaging sequences have shown the ability to distinguish different components in carotid plaque by measuring weightings of basic MR constants. The discrimination capability of MRI mainly depends on the differential of MR constants. Previous studies were mainly focused on the image properties to detect different tissue. For example loose matrix represents hypo intensity in T1 weighted image and hyper intensity in T2 weighted image, while calcification shows hypo intensity in T1, T2 and Pd weighted images. In our study, 4 types of tissue in the plaque were compared quantitatively to find out whether they can be distinguished by routine MR sequences on a clinical 3T system.

15:00 3320.   Identification of vulnerable plaque by MRI and fluorescence imaging in a rabbit model 
Ning HUA1, Fred Baik2, Tuan Pham1, Nick Giordano1, Alkystis Phinikaridou1, Michael Whitney2, Quyen Nguyen2, Roger Tsien2, and James Hamilton1
1Boston University, Boston, MA, United States, 2University of California San Diego, San Diego, CA, United States

Although atherosclerotic plaques frequently remain asymptomatic, sudden disruption of vulnerable plaques(VP) and subsequent thrombosis can be fatal in humans. As part of our research efforts to identify vulnerable plaques prior to acute events, we have combined in vivo MRI and ex vivo optical imaging in a rabbit model of atherothrombosis. Vulnerable features (positive remodeling from in vivo MRI and histology) showed significantly higher uptake of fluorescence probes targeting matrix metalloproteinase (MMP2/9) and thrombin as assessed by ex vivo optical imaging. This is the first validation of a targeted probe for detecting VP in an animal model of controlled plaque disruption.

Electronic Posters : Cardiovascular Imaging
Click on to view the abstract pdf and click on to view the video presentation.
Contrast Enhanced MRA (Non-Coronary)

Monday May 9th
Exhibition Hall  14:00 - 16:00 Computer 34

14:00 3321.   A Novel Approach to ECG-Gated High-Resolution Contrast-Enhanced MR Angiography in Thorax: Technical Aspects 
Yutaka Natsuaki1, Philipp Moritz Wagner2, J Paul Finn2, Randall Kroeker3, and Gerhard Laub1
1Siemens Medical Solutions, Los Angeles, CA, United States, 2Radiology, UCLA, Los Angeles, CA, United States, 3Siemens Medical Solutions, Winnipeg, MB, Canada

Contrast-enhanced MR angiography (ceMRA) is typically performed without ECG gating, and in cardiothoracic applications, variable degrees of blurring may result due to cardiac motion. Alternatively, ceMRA can be acquired with ECG gating, whereby the segmented data acquisition is synchronized with the cardiac cycle and thus minimizes motion-induced blurring. However, conventional gated ceMRA is limited by its acquisition inefficiency, and its spatial resolution and coverage are insufficient for clinical purposes. The current work proposes a novel approach to increasing efficiency and flexibility in ECG-gated ceMRA, and achieves full-coverage high-resolution ECG-gated ceMRA within a single breath hold.

14:30 3322.   Contrast enhanced MR angiography of the thoracic aorta: comparison of ECG-gated techniques at 3T 
Ruth P Lim1, Ryan Avery1, Mary Bruno1, David Mossa1, Gary McNeal2, Yutaka Natsuaki2, and Monvadi B Srichai1
1Radiology, NYU Langone Medical Center, New York, NY, United States, 2Siemens Healthcare, United States

Competing demands of high spatial resolution and short (breath-hold) acquisition times are challenging for ECG-gated contrast enhanced thoracic MRA. We compare two ECG-gated contrast enhanced MRA techniques, one that employs a standard Cartesian acquisition of one partition per heartbeat, and a recently developed technique that uses a zigzag sampling approach in the ky - kz plane for improved scanning efficiency and co-ordination of contrast timing with the cardiac phase of the acquisition. We describe our initial experience in a clinical population.

15:00 3323.   Combined Respiratory and Cardiac Triggered MRA of Congenital Heart Disease with a Blood Pool Contrast Agent 
Shreyas S Vasanawala1, Frandics P Chan1, Beverley Newman1, and Marcus T Alley1
1Radiology, Stanford University, Stanford, CA, United States

Pediatric cardiovascular MRI is degraded by cardiac pulsation and respiratory motion. An SPGR sequence was modified to enable combined cardiac/respiratory triggering and fractional acceleration. 23 pediatric patients undergoing MRI with gadofosveset blood pool agent had triggered and non-triggered acquisitions. Anatomic structures were graded by two experienced readers in randomized blinded fashion and compared directly. Triggered images had higher scores for all structures (Wilcoxon rank-sum test, p<0.05). Triggered images were more likely to be preferred for most structures (one-sided binomial test, p<0.05). The approach enables imaging without suspended respiration, thus reducing depth of anesthesia and need for an artificial airway.

15:30 3324.   Neonatal Congenital Heart Disease: Initial Results with High Resolution Contrast Enhanced MR Angiography at 3.0 Tesla 
John Michael Moriarty1, Kambiz Nael1, Gary Satou2, Pierangello Renella2, Pablo Abbona1, and John Paul Finn1
1Radiology, UCLA Medical Center, Los Angeles, California, United States, 2Pediatric Cardiology, UCLA Medical Center, Los Angeles, California, United States

The purpose of our study was to explore the potential of high resolution CEMRA at 3.0T in neonates with complex congenital heart disease and suspected congenital vascular anomalies. With appropriate use of physiological motion compensation, parallel imaging and coil configuration, voxel volumes less than 0.5 mm3 are routinely achievable. This allows definitive evaluation of pulmonary arterial and venous anomalies, preventing recourse to CT or catheter angiography. Furthermore simultaneous “whole-body” vascular evaluation is feasible, with high resolution images of multiple vascular beds from scalp to groin, even in very low weight, tiny infants.

Tuesday May 10th
  13:30 - 15:30 Computer 34

13:30 3325.   Time-Resolved MR Angiography Pre-Catheter-Based Ablation for Atrial Fibrillation 
Michael Schonberger1, Asad Usman1, Aya Kino1, Andrada Popescu1, Maurizio Galizia1, Jeremy Collins1, James Carr1, and Timothy Carroll1
1Department of Radiology, Northwestern University, Chicago, Illinois, United States

Time-resolved angiography with interleaved stochastic trajectories (TWIST) MR angiography of the pulmonary venous circulation improves arterio-venous separation, does not require exact bolus timing, gives additional information on vein perfusion, and still maintains a high spatial resolution compared to the conventional contrast enhanced-MRA.

14:00 3326.   Diagnostic Accuracy of Contrast-Enhanced MR Angiography and Non-Contrast Proton MR Imaging Compared with CT pulmonary angiography in Chronic Thromboembolic Pulmonary Hypertension 
Smitha Rajaram1, Andy James Swift1, David Capener1, Adam Telfer1, Judith Hurdman2, Robin Condliffe2, Charlie Elliot2, Christine Davies3, Catherine Hill3, David G Kiely2, and Jim M Wild1
1Academic unit of Radiology, University of Sheffield, Sheffield, Yorkshire, United Kingdom, 2Pulmonary Vascular Disease Unit, Royal Hallamshire Hospital, Sheffield,3Department of Radiology, Royal Hallamshire Hospital, Sheffield

The aim of our study was to evaluate the diagnostic accuracy of contrast enhanced MR angiography (c-MRA) and added benefit of non-contrast proton MRI compared to CT pulmonary angiography (CTPA) in patients with chronic thromboembolic disease. Our results show that c-MRA has a very good sensitivity and specificity for diagnosing CTEPH. The sensitivity of c-MRA for visualization of adherent central and lobar thrombus significantly improves with the addition of the SSFP sequence that clearly delineates the vessel wall. CTPA is superior for depiction of intraluminal webs and sub-segmental disease, while c-MRA is superior in identifying stenosis and post-stenotic dilatations

14:30 3327.   High Temporal and Spatial Resolution Imaging of Body AVMs 
Phillip M Young1, Petrice Marie Mostardi1, Michael A McKusick1, and Stephen J Riederer1
1Radiology, Mayo Clinic, Rochester, MN, United States

MRA evaluation of AVMs requires both high spatial resolution and high temporal resolution, which has been made possible by recently developed accelerated imaging techniques. The purpose of this work was to describe the application of one such technique, CAPR, to imaging of AVMs of the upper and lower extremities. Six patient studies have been performed, successfully imaging AVMs of the forearm, hand, thigh and foot. CAPR CE-MRA shows diagnostic quality time-resolved imaging of AVMs of the upper and lower extremities, which may be useful for assessment of the AVM as well as planning of sclerotherapy.

15:00 3328.   MR Angiography using Fractional Contrast Doses with VIPR and HYPR 
Lauren Ashley Keith1, Frank Korosec2, and Charles Mistretta1,2
1Medical Physics, UW - Madison, Madison, WI, United States, 2Radiology, UW - Madison, Madison, WI, United States

This work is motivated by concern over the link between gadolinium-based contrast agents and nephrogenic systemic fibrosis in patients with impaired renal function. By exploiting known benefits of both vastly undersampled isotropic projection reconstruction (VIPR) and highly constrained back projection (HYPR), MRA exams of the lower extremities with 1.0 mm isotropic resolution and 7.35 second temporal resolution have been achieved using half and quarter doses of contrast material (0.05 mmol/kg and 0.025 mmol/kg, respectively) in healthy volunteers and patients.

Wednesday May 11th
  13:30 - 15:30 Computer 34

13:30 3329.   Preoperative mapping of autogenous saphenous veins in patients with PAOD and femorodistal bypass grafting: Prospective comparison of peripheral MR angiography using a blood pool contrast agent with ultrasound and intraoperative findings 
Ann Marie Jah-Kabba1, Guido Matthias Kukuk1, Dariusch Reza Hadizadeh1, Arne Koscielny2, Frauke Verrel2, Hans Heinz Schild1, and Winfried Albert Willinek1
1Department of Radiology, University of Bonn, Bonn, NRW, Germany, 2Department of Vascular Surgery, University of Bonn, Bonn, NRW, Germany

MR angiography (MRA) in the equilibrium phase performed with a blood pool contrast agent (BPCA) allows for visualization of the veins in addition to arterial imaging without the need of a second contrast injection. Mapping of autogenous saphenous veins as an imaging adjunct to peripheral MRA with the BPCA Gadofosveset was feasible without significant differences as compared to duplex ultrasound. It correctly allowed selection of candidates for autogenous venous graft surgery and may replace time-intensive venous ultrasound in the preoperative work-up of patients with peripheral arterial occlusive disease (PAOD).

14:00 3330.   Qualitative and quantitative evaluation of contrast-enhanced MR venography (MRV) of the lower extremities with a blood pool agent compared to noncontrast MRV 
Charles Yoon Kim1, Steven Huang1, Rajan Gupta1, Michael Miller1, Mark Lessne1, Pranay Krishnan1, Nicholas Befera1, Paul Evans1, and Elmar M Merkle1
1Radiology, Duke University Medical Center, Durham, NC, United States

MR venography for the detection of deep venous thrombosis is typically performed using noncontrast techniques, due to the difficulty of achieving adequate venous opacification of the lower extremities. Theoretically, a blood pool agent would be able to overcome these limitations. The purpose of this study is to qualitatively and quantitatively evaluate the use of gadofosveset for imaging the lower extremity venous system compared to a conventional noncontrast gradient recalled echo (GRE) sequence, which has been proven to be highly sensitive and specific for the detection of DVT.

14:30 3331.   Three-station MR angiography with high-resolution steady-state vascular imaging using ferumoxytol 
Pippa Storey1, Mary Theresa Bruno1, Ruth P Lim1, Hersh Chandarana1, David R Stoffel1, and Vivian S Lee1
1Radiology Department, New York University School of Medicine, New York, New York, United States

Feraheme (ferumoxytol) is an ultrasmall superparamagnetic iron oxide (USPIO) agent that has recently been approved for human use in the United States. It has high T1 relaxivity and is not eliminated by the kidney, making it a potential alternative to gadolinium for vascular imaging in patients with renal insufficiency. We show that ferumoxytol can successfully be used in a conventional three-station MRA protocol, despite the fact that the dose injected for time-resolved imaging does not leave the blood pool before bolus-chase imaging. Furthermore, the long plasma half-life (15 hours) can be exploited to provide high-resolution steady-state images for venous assessment.

15:00 3332.   Single dose large anatomical coverage contrast-enhanced peripheral MRA using a novel broadband digital MR architecture: Initial experience 
Tim Leiner1, Eveline Alberts2, Liesbeth Geerts2, Mark Stoesz2, Fredi Visser1, Willem Mali1, and Jeroen Hendrikse1
1Department of Radiology, Utrecht University Medical Center, Utrecht, Netherlands, 2Clinical Science Division, Philips Medical Systems, Best, Netherlands

High dose peripheral contrast-enhanced MR angiography (CE-MRA) is losing attractiveness due to advances in MR hardware and software as well as complications associated with gadolinium-based contrast agents . We describe a novel fully digital MR architecture with intrinsically higher signal-to-noise ratio coils that was used to to improve 1) anteroposterior coverage, 2) acquisition resolution, and 3) to reduce contrast agent dose from a double to a single dose. At the same time good image quality was preserved, both by subjective and objective image quality measures.

Thursday May 12th
  13:30 - 15:30 Computer 34

13:30 3333.   Highly Accelerated Abdominal CE-MRA with 3D Timing Scan 
Petrice Marie Mostardi1, James F Glockner1, and Stephen J Riederer1
1Mayo Clinic, Rochester, MN, United States

High spatial and temporal resolution are desired in abdominal CE-MRA, which is particularly challenging due to the limited scan time and need to image over a large FOV. In this work an abdominal CE-MRA method for high spatial and temporal resolution imaging is developed that implements the CAPR sampling method, high (R¡Ý8) SENSE accelerations and specialized receiver coil arrays. Volunteer and patient studies have been performed using an imaging protocol that consists of a low-dose (2 ml) time-resolved 3D CAPR acquisition that provides an overview of the vasculature and serves as a timing bolus for a subsequent high spatial resolution single phase CAPR renal MRA.

14:00 3334.   Comparison of Renal MRA/CTA and DSA in CORAL Study 
Honglei Zhang1, Alan H Matsumoto2, Donald Cutlip3, Timothy P Murphy4, Christopher J Cooper5, Lance D Dworkin6, and Martin R Prince1
1Radiology, Weill Cornell Medical College, New York, NY, United States, 2Radiology, University of Virginia, Charlottesville, VA, United States, 3Clinical Investigations, Harvard Clinical Research Institute, Boston, MA, United States, 4Diagnostic Imaging, Rhode Island Hospital, Providence, RI, United States, 5Medicine, The University of Toledo, Toledo, OH, United States, 6Department of Medicine, Alpert Medical School of Brown University, Providence, RI, United States

A total of 132 renal MRAs and 64 CTAs were reviewed by MRA/CTA core lab for randomization into Cardiovascular Outcomes of Renal Atherosclerotic Lesions (CORAL) study, of which only 85 (43%) had > 60% stenosis. For the 29 randomized to angioplasty/stent therapy, DSA confirmed that MRA correctly identified 87% lesions as hemodynamically significant. In 77 MRA studies with local reports, core lab readings were consistent with the readings by local radiologist in 39 patients (51%). Local radiologists overestimated renal artery stenosis severity in 29 of 170 arteries and missed 7/16 accessory renal arteries.

14:30 3335.   Ultra high resolution 3D microangiography of the rat ocular circulation at 11.7 T 
Yen-Yu Ian Shih1, Eric R Muir1, Li Guang1, Bryan H De La Garza1, and Timothy Q Duong1
1Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States

This study developed an ultra high resolution microangiographic technique (up to nominal 35µm isotropic resolution) for the in vivo rat eye at11.7 T. The effects of gas challenges and MION contrast agent were also investigated. In addition, a 3D eyeball flattening technique was developed to isolate the vascular pattern at different depth of the retinal thickness. The structural details of the ocular vascular system can be clearly identified using ultra high resolution ocular MR microangiography, which is not previously available. This technique has potential to complement existing optical imaging angiographic techniques for the eye.

15:00 3336.   4D contrast enhanced MRA using single dose dual injections and constrained reconstruction 
Yijing Wu1, Kevin Johnson1, Steven Kecskemeti2, Charles A Mistretta3, and Patrick A Turski4
1Medical Physics, University of Wisconsin, Madison, MADISON, WI, United States, 2Medical Physics, University of Wisconsin, Madison, 3Medical Physics and Radiology, University of Wisconsin, Madison, 4Radiology, University of Wisconsin, Madison

Time-resolved contrast-enhanced magnetic resonance angiography (TR CE MRA) of the brain is challenging due to the need for rapid imaging and high spatial resolution. An innovative technique is presented to split a single dose contrast into two injections. The first small contrast volume (2~3 ml) will be used for acquiring time-resolved weighting images with high frame rate and the rest of contrast agent will be used for a high resolution CE MRA as the spatial constraint. Using HYPR reconstruction, the final images (HYPR CE) will have both high temporal and spatial resolution, but not suffer the flow-sensitive artifacts and increase of contrast dosage. Furthermore, volunteer studies demonstrate that reduced contrast dose from the first injection significantly improves the arterial and venous separation.


Electronic Posters : Cardiovascular Imaging
Click on to view the abstract pdf and click on to view the video presentation.
Contrast-free MRA
Monday May 9th
Exhibition Hall  14:00 - 16:00 Computer 35

14:00 3337.   Three dimensional non-contrast MRA of the lower extremities using stepping thin slab acquisition: Initial experience in healthy subjects 
Thanh D Nguyen1, Mitchell Cooper2, Pascal Spincemaille1, Priscilla Winchester1, Martin R Prince1, and Yi Wang1
1Radiology, Weill Cornell Medical College, New York, NY, United States, 2Biomedical Engineering, Cornell University, Ithaca, NY, United States

We propose to develop an inflow based 3D non-contrast MRA sequence using stepping thin slab acquisition for lower extremity imaging. This sequence can provide improved inflow effect compared to conventional thick slab 3D acquisition as well as better SNR with higher resolution compared to 2D acquisition. Initial results from healthy subjects demonstrated 21% higher SNR in 60% less scan time compared to conventional ECG-gated 2D time-of-flight acquisition.

14:30 3338.   Accuracy of Non-Contrast Fresh-Blood MRA for the Assessment of Lower Extremity Peripheral Vascular Disease 
Timothy SE Albert, MD1, Erin J Kelly, PhD2, Patrik Zetterlund, MD1, Connie Luna, RT1, Nancy Yellin, RN1, and Mitsue Miyazaki, Ph.D.3
1Salinas Valley Memorial Hospital Cardiovascular Diagnostic Center, Monterey, CA, United States, 2Toshiba America Medical Systems, Tustin, CA, 3Toshiba Medical Research Institute USA, Inc, Vernon Hills, IL

A clinical population with a variety of vascular disease underwent a non-contrast 3D FS-FBI MRI exam and an X-Ray angiography exam. The accuracy of FS-FBI was evaluated in the assessment of various vascular diseases compared to conventional X-Ray Angiography. Using a 25-segment model blinded analysis of FBI images and DSA images, both image quality (poor-1; good-2; excellent-3) and stenotic severity (Non Diagnostic (ND), 0-25%, 26-50%, 51-75%, 76-99%, total occlusion) were compared. Overall clinical accuracy revealed a sensitivity of 0.90, specificity 0.94, positive predictive value 0.81, and negative predictive value of 0.97. In comparison to DSA, FBI shows high clinical accuracy.

15:00 3339.   Optimization of the First-Order Gradient Moment for Flow-Sensitive Dephasing Magnetization-Prepared 3D Noncontrast MRA 
Zhaoyang Fan1,2, Xiangzhi Zhou2, Xiaoming Bi3, Sven Zuehlsdorff3, Rohan Dharmakumar1,2, James Carr2, and Debiao Li1,2
1Cedars-Sinai Medical Center, Los Angeles, California, United States, 2Northwestern University, Chicago, Illinois, United States, 3Siemens Healthcare, Chicago, Illinois, United States

Flow sensitization imparted by the flow-sensitive dephasing (FSD) preparation is essential for FSD-prepared noncontrast MRA, and its strength can be measured by the first-order gradient moment, m1. Incomplete delineation of arterial segments may result from a suboptimal m1. The optimal m1, however, is subject and artery specific. The aim of this work was to systematically investigate the utility of a 2D m1-scouting method for improving imaging quality of 3D FSD MRA. From 10 healthy subjects and 1 patient, significant increases in artery SNR and artery-vein CNR on MRA’s were obtained using this optimization procedure, which potentially help enhance diagnostic confidence.

15:30 3340.   Non-contrast-enhanced peripheral MRA: Comparison of 3D fast spin-echo based and flow sensitive dephasing prepared steady state free precession techniques at 1.5 T 
Ruth P Lim1, Zhaoyang Fan2, Manjil Chatterji3, Amanjit Baadh1, Iliyana Atanasova1, Pippa Storey1, Danny C Kim1, Sooah Kim1, Philip Hodnett1, Afshan Ahmad1, David Stoffel1, James S Babb1, Daniel Kim1, Qun Chen1, Jian Xu4, Debiao Li2,5, and Vivian S Lee1,5
1Radiology, NYU Langone Medical Center, New York, NY, United States, 2Radiology, Cedars-Sinai Medical Center and UCLA, Los Angeles, California, United States,3Radiology, Mt Sinai School of Medicine, New York, NY, United States, 4Siemens Healthcare, New York, NY, United States, 5Co-Senior Author

Slow arterial flow in the below-knee vessels is challenging for ECG-gated flow-dependent non-contrast-enhanced MRA techniques. We evaluate the performance of variable (VFA MRA) and constant (CFA MRA) flip angle fast spin echo MRA, and flow sensitive dephasing prepared steady state free precession MRA (FSD MRA) in a clinical population. Our results show comparable accuracy between the three sequences, with gadolinium-enhanced MRA as the reference standard. Image quality was highest for FSD-MRA, and fast diastolic flow was problematic for VFA MRA due to flow dephasing in diastole.

Tuesday May 10th
  13:30 - 15:30 Computer 35

13:30 3341.   Optimization of Non-Contrast Enhanced Time-SLIP for Carotid Artery Imaging 
William W. Orrison Jr. MD, MBA1,2, Erin J. Kelly, PhD3, Denise Moreau, RT 3, Cayce J. Roach4,5, and Eric H. Hanson MD, MPH4,5
1CHW Nevada Imaging Company, Las Vegas, NV, United States, 2Touro University Nevada, Henderson, NV, United States, 3Toshiba America Medical Systems, Tustin, CA,4University of Nevada Las Vegas, 5Advanced Medical Imaging and Genetics (Amigenics)

Three-dimensional time-of-flight is now commonly used in routine magnetic resonance angiography studies of the neck, however there are limits to its temporal and spatial resolution, which contrast-enhanced protocols have addressed. The utility of Time-SLIP to produce bright blood 3D angiograms of the carotid arteries has been under investigation. However, the high flow speed of blood through the carotid arteries can contribute to poor image quality in combination with suboptimal tag placement and BBTI selection along with poor cardiac synchronization. This optimization study served as an initial feasibility study for non-contrast Time-SLIP angiography of the carotid arteries.

14:00 3342.   Flow Independent Breast MR Angiography using a Variable Flip Angle Turbo Spin Echo Sequence 
Yi Wang1,2, Karl Diedrich2, Glen Morrell2, Allison Payne2, and Dennis L. Parker1,2
1Bioengineering, University of Utah, Salt Lake City, UT, United States, 2Radiology, Utah Center for Advanced Imaging Research, Salt Lake City, UT, United States

Breast tumor growth is highly dependent on angiogenesis. Visualization of the breast vasculature helps assisting pre-surgical staging, treatment planning, detection of tumor reoccurrence and post-treatment evaluation in breast cancer management. For example, in Magnetic Resonance guided High-Intensity Focused Ultrasound, treatment planning and control would be improved by characterizing the vascular distribution around the target lesions and including the resulting convective effects in the appropriate models. Knowledge of the vasculature is also useful at the pre-treatment planning stage where an accurate segmentation of the treatment volume on a voxel-by-voxel basis is desired. Even though contrast-enhanced MRI has becoming a standard tool for breast cancer diagnosis, the association between contrast injection and the development of nephrogenic systemic fibrosis has raised concern, especially for patients with renal failure. To reduce these concerns, non-contrast enhanced breast vessel imaging has been investigated using a peripheral pulse gate-triggered half-Fourier turbo spin echo sequence. In this work, an untriggered variable flip angle turbo spin echo sequence was explored as a non-contrast flow-independent MR angiography technique to achieve breast vasculature imaging.

14:30 3343.   Non-Contrast Thoracic MRA within Single Breath-Hold Using Highly-Accelerated Parallel Imaging 
Jian Xu1,2, Kellyanne Mcgorty1, Ruth Lim1, Mary Bruno1, Monvadi Srichai1, Daniel Kim1, and Daniel Sodickson1
1Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, United States, 2PolyTechnic Institute of NYU and Siemens Medical Solutions USA Inc., New York, NY, United States

ECG-triggered CE-MRA of the thoracic aorta is challenging, due to competing demands of high spatial resolution and high temporal resolution within a breath-hold (BH). ECG-triggered NC-MRA is an alternative method for patients with poor intravenous access or contraindications to gadolinium administration without subtraction. ECG-triggered NC-MRA based on T2-prepared and fat suppressed balanced steady state free precession imaging with navigator gating has been shown to produce good image quality, but can take approximately 10 minutes. We propose to perform single BH ECG-triggered NC-MRA of the thoracic aorta using highly accelerated parallel imaging and compare it against ECG-triggered CE-MRA.

15:00 3344.   Dynamic Angiography Imaging at 7T Using Variable Duration Pseudo-Continuous Arterial Spin Labeling 
Onur Ozyurt1, Ann-Kathrin Homagk2, Michael Bock2, and Cengizhan Ozturk1
1Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey, 2Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany

In dynamic angiography, inflow of labeled blood to the target volume is imaged at various delay times. In this study, using a variable duration Pseudo-Continuous Arterial Spin Labeling (pCASL) for each inflow time is proposed and utilized in a dynamic angiography study at 7T.

Wednesday May 11th
  13:30 - 15:30 Computer 35

13:30 3345.   Non Contrast 3D Volumetric Time-Resolved MRA in Renal Artery(CINEMA-RENAL) 
Masanobu Nakamura1, Masami Yoneyama1, Tomoyuki Okuaki1, Takashi Tabuchi1, Atsushi Takemura2, Makoto Obara2, and Junko Ogura1
1Medical Satellite Yaesu Clinic, Chiyoda-ku, Tokyo, Japan, 2Philips Electronics Japan, Tokyo, Japan

Non-contrast MRA with spin-labeling technique which discriminates arteries from veins, simultaneously suppressing signals from surrounding tissues, has been applied for exploring the renal artery. Currently available techniques for non-contrast MRA, however, enable only to gain static, single-frame images. Recently we have proposed 3D volumetric non contrast time-resolved MRA technique termed Contrast inherent inflow enhanced multi phase angiography in renal artery (CINEMA-RENAL). CINEMA-RENAL sequence was performed combining Look-Locker techniques with 3D segmented T1-weighted gradient echo sequence. Radial 3D stack-of-stars acquisition was used to diminish the motion artifacts due to breathing. CINEMA -RENAL can extract the blood flow in the renal artery at an interval of 100 ms and thus permitted us to observe vascular construction in full by preparing MIP images of axial, coronal, and sagittal acquisitions. CINEMA enables to achieve ``four dimensional`` images without contrast agents.

14:00 3346.   Arterial Spin Labeling Angiography without the Need of Subtraction using a Triple Inversion Recovery Prepulse 
Marcelo E Andia1, and Rene M Botnar1
1Division of Imaging Sciences and Biomedical Engineering, Kings College London, London, United Kingdom

In this work we present a new ASL approach for non-enhanced MRA without the need of subtraction. Triple inversion recovery TIR-ASL exploits the ability of the Nonselective Double Inversion-Recovery sequence to null background signal while maintaining the signal in labeled blood using a regional inversion pulse.

14:30 3347.   Non-contrast Outer Radial Inner Square k-space Scheme (NORISKS)- a breath-held balanced SSFP-Dixon technique for non-contrast enhanced renal MRA 
Manojkumar Saranathan1, Pauline W Worters1, and Shreyas Vasanawala1
1Radiology, Stanford University, Stanford, CA, United States

Nephrogenic systemic fibrosis (NSF) concerns associated with Gadolinium based contrast agents have spurred a resurgence in non-contrast enhanced MR Angiography (MRA) methods. Balanced steady state free precession (b-SSFP) imaging [1-3], due to its high SNR/CNR and short scan times, has been successful in coronary and renal angiography. Most current methods use respiratory gating which performs poorly during irregular breathing/sleep apnea. We propose a 3D b-SSFP-Dixon technique with a novel k-space segmentation scheme for breath-held (BH) non-contrast renal MRA without compromising coverage or spatial resolution. The sequence was tested on healthy subjects as well as patients.

15:00 3348.   Noncontrast MR Angiography for Comprehensive Assessment of Abdominopelvic Arteries using Quadruple Inversion-Recovery Preconditioning and 3D balanced Steady-State Free Precession Imaging 
Iliyana P Atanasova1,2, Daniel Kim1, Ruth P Lim1, Pippa Storey1, and Vivian S Lee1
1New York University, New York, New York, United States, 2Columbia University, New York, New York, United States

A new non-contrast MRA pulse sequence was developed using 4 inversion-recovery (IR) pulses and 3D b-SSFP readout to provide complete coverage from renal to external iliac arteries with excellent background suppression. Respiratory triggered, non-contrast angiograms were obtained in four volunteers and one patient referred for contrast-enhanced MRA. In all subjects, MRAs exhibited excellent arterial conspicuity from the renal to the external iliac arteries with optimal background suppression. Infrarenal aortic atherosclerosis was well-visualized in the patient in good agreement with CE MRA. The new NC MRA pulse sequence provides high spatial resolution arteriograms within clinically feasible scan times of 6 min.

Thursday May 12th
  13:30 - 15:30 Computer 35

13:30 3349.   Noncontrast MRA at 3T 
Mitsue Miyazaki1,2, Yuichi Yamashita2, Andrew Wheaton1, Wayne Dannels1, Robert Anderson1, Leping Zha1, and Satoshi Sugiura2
1Toshiba Medical Research Institute USA, Vernon Hills, IL, United States, 2Toshiba Medical Systems, Otawara, Tochigi, Japan

Despite the recent advancements in 3T, non-contrast MRA faces many problems such as a specific absorption rate (SAR) and B1 inhomogeneity. The B1 wavelength effect caused by conventional quadrature RF transmission makes shading or nonuniform signal intensity unavoidable, especially in abdominal and peripheral MRA. In this study, we have adjusted the pulse sequences to lower SAR and addressed the signal shading issue by applying multi-phase RF transmission. In a result, multi-phase RF transmission sufficiently mitigates the B1-related signal shading issue for MRA.

14:00 3350.   Aorto-Iliac Flow-Sensitive 4D MRI: Normal and Altered Flow Characteristics in Abdominal Aneurysms 
Jörg Mauch1, Michael Markl1, Christoph Haller2, Zoran Stankovic1, Mathias Langer1, and Julia Geiger1
1Radiology, Medical Physics, University Medical Center, Freiburg, Germany, 2Cardiovascular Surgery, University Medical Center, Freiburg, Germany

The purpose of this study was to employ flow-sensitive 4D MRI for the characterization and quantification of aorto-iliac hemodynamics in patients with infrarenal abdominal aortic aneurysms. Compared to healthy volunteers, patients showed a more heterogeneous distribution of flow and demonstrated substantial flow deceleration during passage through aneurysm and sudden flow acceleration distal to the aneurysm in the proximal iliac arteries. Quantitative analysis revealed significant changes in peak velocities, total flow, and flow distribution to the left and right iliac arteries. The magnitude and extent of such alterations may thus be an indicator of aneurysm progression or onset of thrombosis.

14:30 3351.   Evaluation of Venous Spread of Renal Cell Carcinoma by Non-Contrast-Enhanced Magnetic Resonance venography: a SLEEK sequence 
yigang pei1, and daoyu hu2
1Department of Radiology, Tongji Hospital,Tongji Medical College,Huazhong University of Science and Technology, wuhan, Hubei, China, People's Republic of, 2Department of Radiology, ongji Hospital,Tongji Medical College,Huazhong University of Science and Technology, wuhan, Hubei, China, People's Republic of

Doppler sonography, MDCTV and CE-MRV scan are often used to diagnose renal vein thrombosis for renal cell carcinoma patients or evaluate renal venous system for kidney transplant patients and donors. Doppler sonography is a non-invasive and easy method, but the results are operator dependant. CE-MRV and MDCTV can show clearly the presence of tumor thrombus in inferior vena cava with renal cell carcinoma, but they are depending on Gd or iodine contrast mediums. The contrast enhanced technique has its limitations: 1: may cause nephrogenic systemic fibrosis (NSF) or contrast-Induced Nephropathy; 2: a relatively expensive examination; 3: the arterial contamination. So, in our study, a new non-contrast-enhanced MR venography (a SLEEK technique) was developed to delineate the venous spread of RCC.

15:00 3352.   Efficient Substitute for Inversion Preparation in TSE Angiography 
Jason K Mendes1, and Dennis L Parker1
1University of Utah, Salt Lake City, UT, United States

Turbo spin echo (TSE or FSE) is an important technique in the discrimination of atherosclerotic plaque components such as hemorrhage, disrupted fibrous cap, lipid/necrotic core, calcification and ulceration. To distinguish between stationary tissue and flowing blood, several techniques such as Double Inversion Recovery (DIR), Quadruple Inversion Recovery (QIR) or Motion-Sensitized Driven-Equilibrium (MDSE) have been proposed These suppression techniques involve various combinations of inversion pulses over a large volume outside the slice(s) of interest. This prevents efficient interleaving of multiple slices and results in a dramatic increase in total scan time. This work utilizes a novel dynamic TSE sequence (cineTSE) to provide analogous information to blood suppression techniques with no increase in scan time over a typical (non-inversion prepared) TSE protocol.