Electronic Posters: Cardiovascular

Thursday 13:30-15:30 Computer 34

13:30 3660. Monitoring Iron Chelation Effect in Hearts of Thalassaemia Patients with Improved Sensitivity Using Reduced Transverse Relaxation Rate (RR2)

Jerry S. Cheung^1,2, Wing-Yan Au³, Shau-Yin Ha⁴, Jens H. Jensen⁵, Dan Kim⁵, Abby Y. Ding^1,2, Iris Y. Zhou^1,2, Hua Guo⁵, Truman R. Brown⁶, Winnie C.W. Chu⁷, Darshana D. Rasalkar⁷, Pek-Lan Khong⁸, Gary M. Brittenham⁹, Ed X. Wu<sup>1,2

1</sup>Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China; ²Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China; ³Department of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China; ⁴Department of Pediatrics and Adolescent Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China; ⁵Department of Radiology, New York University School of Medicine, New York, United States; ⁶Department of Radiology, Columbia University, New York, United States; ⁷Department of Diagnostic Radiology and Organ Imaging, The Chinese University of Hong Kong, Hong Kong SAR, China; ⁸Department of Diagnostic Radiology, The University of Hong Kong, Pokfulam, Hong Kong SAR, China; ⁹Department of Pediatrics, Columbia University, New York, United States

Accurate MRI characterization of myocardial iron is needed to improve the diagnosis and management of thalassaemia patients with transfusional iron overload. This study aimed to demonstrate that a new transverse relaxation index, the reduced R2 (RR2) that is estimated from non-monoexponential multi-echo CPMG signal decay and sensitive to ferritin iron, could detect the myocardial iron changes immediately following 1-week iron chelation suspension in thalassaemia patients at 3T.

14:00 3661. Quantitative T1 and T2 Measurements of Tissue Characteristics in Myocardial Infarction – Pilot Results at 3T

Stefan K. Piechnik¹, Erica Dall'Armellina¹, Vanessa M. Ferreira¹, Lowri E. Cochlin², Jürgen E. Schneider¹, Stefan Neubauer¹, Matthew D. Robson<sup>1

1</sup>Cardiovascular Medicine, OCMR, Oxford University , Oxford, Oxfordshire, United Kingdom; ²Dept of Physiology, Anatomy and Genetics, Oxford University, Oxford, Oxfordshire, United Kingdom

We present preliminary results of T1- and T2-mapping at 3T in sub-acute myocardial infarction to demonstrate the ability of quantitative CMR in delineating myocardial tissue changes following an ischemic event.

14:30 3662. Free-Breathing, Single Shot Fat-Water Separated Cardiac Imaging with Motion Corrected Averaging

Peter Kellman¹, Diego Hernando², Saurabh Shah³, Christophe Chefd'hotel⁴, Z-P Liang², Andrew E. Arai<sup>1

1</sup>National Institutes of Health, Bethesda, MD, United States; ²University of Illinois, Urbana, IL, United States; ³Siemens Medical Solutions, Chicago, IL, United States; ⁴Siemens Corporate Research, Princeton, NJ, United States

A rapid fat/water separated imaging protocol has been developed for free-breathing cardiac applications for cases where patients have difficulty breath-holding or have significant arrhythmias. The method combines a 2 echo GRE acquisition and parallel imaging, and may be used with repeated measurements and motion corrected averaging to further improve image quality. The method has been applied to both pre-contrast and late enhancement imaging.

15:00 3663. Navigator Guided High-Resolution Single-Shot Black-Blood TSE Images Using ZOOM and Sensitivity Encoding (SENSE) on a 32 Channel RF System

Raja Muthupillai¹, Amol Pednekar², Claudio Arena¹, Scott D. Flamm¹, Benjamin Y. Cheong<sup>1

1</sup>Diagnostic and Interventional Radiology, St. Luke's Episcopal Hospital, Houston, TX, United States; ²Philips Healthcare

We demonstrate that by using a judicious combination of reduced FOV imaging (ZOOM), Sensitivity Encoding (SENSE), and half-scan, it is feasible to obtain diagnostic quality single-shot (SSH) dual-inversion recovery prepared black blood(BB) turbo spin echo(TSE) images with minimal image blurring during normal respiration. The results of the study, performed on 8 asymptomatic subjects, show that SSH T2-TSE images acquired using ZOOM+SENSE under navigator triggering, yield images with quality that is comparable to conventional multi-shot BB-TSE images acquired over a 14-16 heart beat breathhold.

Coronary Artery & Vessel Wall Imaging

Hall B Monday 14:00-16:00 Computer 35

14:00 3664. Retrospective Estimation of 3D Respiratory Motion Vectors in Coronary MRI

Alan Christopher O'Connor¹, Mehdi Hedjazi Moghari¹, Peng Hu¹, Dana C. Peters¹, Warren J. Manning¹, Reza Nezafat¹, Roger Ware Brockett<sup>2

1</sup>Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States; ²SEAS, Harvard University, Cambridge, MA, United States

Navigator correction methods were developed to increase the gating window size possible for free-breathing cardiac MRI and consequently reduce scan time. These methods typically rely on a generic scale-factor between measured diaphragm motion and heart motion. We present a novel scheme for estimating patient-, direction-, and coil-specific motion vectors directly from the scan data to correct for phase errors caused by respiratory motion of the heart.

14:30 3665. Quantitative Assessment of Right Coronary Artery MRI Using Quadrature RF Coils at 7 Tesla, Incorporating a Direct Comparison of Results to Those Acquired at 3 Tesla.

Saskia van Elderen¹, Maarten Versluis¹, Jos Westenberg¹, Harsh Agarwal², Nadine Smith¹, Matthias Stuber³, Albert de Roos¹, Andrew Webb<sup>1

1</sup>Radiology, Leiden University Medical Center, Leiden, Netherlands; ²Johns Hopkins University; ³Department of Radiology, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland

Using a quadrature RF coil with dimensions optimized for reliable navigator gating, this study with ten volunteers shows that 7T right coronary angiograms can be acquired with improved vessel sharpness compared to those obtained at 3T using identical imaging parameters.

15:00 3666. The Influence of Sublingual Nitroglycerin on Contrast -Enhanced Whole-Heart Coronary Magnetic Resonance Angiography at 3.0-T

Bin Sun¹, ZhiYong Chen², LiXin Jin³, Qing Duan

¹Radiology, FuJian Medical University Union Hospital, FuZhou, FuJian, China; ²Radiology, FuJian Medical University Union Hospital, China; ³Siemens Healthcare, MR Collaboration NE Asia, China

This article describes the influence of sublingual nitroglycerin spray on the lumen diameter, number of side branches visualized, average vessel length of 3.0-T contrast-enhanced whole-heart coronary magnetic resonance angiography. Twenty-four patients were prospectively included in this study: 12 were examined without sublingual nitroglycerin, and 12 were examined after the administration of sublingual nitroglycerin. Two blinded observers quantitatively assessed lumen diameter and length in the RCA, LAD and LCX. The number of acute marginal branches and septal branches was counted. The number of clinical side effects was evaluated. Sublingual nitroglycerin spray significantly dilates the coronary arteries and allows more side branches to be visualized at 3.0-T contrast-enhanced whole-heart CMRA without increasing resolution or increasing the number of side effects.

15:30 3667. 3T Coronary MRA Using 3D Multi-Interleaved Multi-Echo Acquisition and VARPRO Fat-Water Separation

Saurabh Shah¹, Xiaoming Bi¹, Diego Hernando², Peter Weale¹, Sven Zuehlsdorff¹, Sonia Nielles-Vallespin³, Peter Kellman<sup>4

1</sup>Siemens Healthcare, Chicago, IL, United States; ²University of Illinois at Urbana-Champaign, Urbana, IL, United States; ³Royal Brompton And Harefield NHS Foundation Trust, London, United Kingdom; ⁴National Institutes of Health / NHLBI, Bethesda, MD, United States

A 3D free-breathing navigator-gated multi-interleaved multi-echo GRE sequence is implemented with VARPRO fat-water separation and utilized in targeted acquisition of coronary arteries at 3T. This approach achieves reliable fat-suppression across field-of-view and provides clear depiction of coronaries for enhanced visualization.

Tuesday 13:30-15:30 Computer 35

13:30 3668. Prospective Respiratory Navigator Gated RF Excitation in Whole-Heart Coronary MRA at 3T

Jing Yu^1,2, Michael Schär, ²³, Harsh Agarwal, ^2,4, Matthias Stuber<sup>2,5

1</sup>Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States; ²Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States; ³Philips Healthcare, Cleveland, OH, United States; ⁴Department of Electrical and Computer Engineering, John Hopkins University, Baltimore, MD, United States; ⁵Department of Radiology, University Hospital Center and University of Lausanne (CHUV), Lausanne, VD, Switzerland

One of the challenges in coronary MRA is insufficient SNR. To improve the blood-pool SNR in prospective respiratory navigator gated whole-heart coronary MRA, radiofrequency excitations of the gradient echo readout train are suspended in real-time, when the respiratory position is outside the predefined gating window. Phase encoding is adapted to deposit the increased signal in central k-space and to minimize signal variation of adjacent k-space profiles. Consistent with the numerical simulation, in vivo experiments demonstrated 35% improvement in blood-pool SNR, without compromising scan time or spatial resolution. The SNR advantage affords great potential towards better depiction of the coronary arteries.

14:00 3669. Coronary Sinus Flow Quantification at 3T and Cold Pressor Test for Non Invasive Evaluation of Coronary Endothelial Function

Pierre-Julien Moro^1,2, Alexis Jacquier¹, Frank Kober¹, Jean-Louis Bonnet², Patrick Cozzone¹, Monique Bernard<sup>3

1</sup>Centre de Résonance Magnétique Biologique et Médicale, CNRS UMR 6612, Université de la Méditerranée, Faculté de Médecine, Marseille, France; ²Cardiology, CHU Timone, Marseille, France; ³Centre de Résonance Magnétique Biologique et Médicale, CNRS UMR 6612, Université de la Méditerranée , Faculté de Médecine, Marseille, France

The purpose of this study was to assess a non invasive measure of coronary endothelial function. Coronary sinus flow was measured in 14 volunteers at rest and during cold pressor test (CPT) using non breath-hold velocity encoded phase contrast cine MRI. Myocardial blood flow (MBF) significantly increased by 55 ± 38 % during CPT compared to the rest examination (p<0.0001); coronary blood flow was 0.66 ± 0.22 ml/min/g at baseline and 1.03 ± 0.41 ml/min/g after CPT. This non invasive measure may help to detect changes in endothelial function which occur early in a variety of cardiovascular diseases.

14:30 3670. Prospective Projection-Based Respiratory Whole-Heart Coronary MRI with Patient-Specific Tracking Factor

Mehdi Hedjazi Moghari¹, Peng Hu¹, Christian Stoeck², Jouke Smink³, Dana C. Peters¹, Beth Goddu¹, Lois Goepfert¹, Warren J. Manning¹, Reza Nezafat<sup>1

1</sup>Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States; ²University and ETH, Biomedical Engineering, Zurich, Switzerland; ³Philips-Healthcare, Best, Netherland

The impact of correct subject-dependent slice tracking factor in whole-heart coronary imaging is studied in this paper. In preparation phase, two projection-based respiratory navigators are positioned at the diaphragm edge and center of heart to calculate the slice tracking factor. The projection-based navigator at the diaphragm with the estimated scale factor is employed for the whole-heart coronary image reconstruction. The constructed images outperform the ones acquired with the pencil beam navigator with the constant scale factor 0.6.

15:00 3671. Feasibility Study of Motion Pre-Analysis Method for Whole-Heart Magnetic Resonance Coronary Angiography (Wh Mrca) at Different Breathing Levels

Shigehide Kuhara¹, Tomohisa Okada², Ayako Ninomiya¹, Toshikazu Kamae², Shotaro Kanao², Tetsuo Sato³, Kotaro Minato³, Kaori Togashi<sup>2

1</sup>MRI Systems Division, Toshiba Medical Systems, Otawara-Shi, Tochigi, Japan; ²Department of Diagnostic Radiology, Kyoto University Hospital, Kyoto, Japan; ³Nara Institute of Science and Technology, Nara, Japan

We have developed the Motion Pre-Analysis Method to determine the appropriate RMC coefficient before WH MRCA (Whole Heart Magnetic Resonance Coronary Angiography) examinations and investigated coefficients between motions of the diaphragm and the heart at different breathing levels by using an inflatable blood pressure cuff placed under an abdominal band. The results of this study suggest that the RMC coefficient may change for each person and abdominal pressures applied. The image quality was slightly improved by using the pre-analyzed RMC coefficient. It is therefore expected that this Motion Pre-Analysis Method would improve visualization of WH MRCA examinations.

Wednesday 13:30-15:30 Computer 35

13:30 3672. Local Inversion Spiral Coronary Vessel Wall Imaging: A Comparison Between 1.5T and 3T

Sarah Anne Peel¹, Tarique Hussain¹, Gerald Greil¹, Tobias Schaeffter¹, René M. Botnar<sup>1

1</sup>Division of Imaging Sciences, King's College London, London, United Kingdom

In this study we sought to compare the 3D spiral coronary vessel wall imaging using the local inversion pre-pulse technique on 1.5T and 3T systems. Imaging at 1.5T resulted in consistent image quality and good blood suppression. While SNR was improved at 3T, image quality was more consistent and artifact level lower at 1.5T. Although excellent coronary vessel wall images can be acquired at 3T, improvements in shimming and f0 determination are required to improve overall robustness compared to 1.5T.

14:00 3673. The Use of Biofeedback with MCLAWS to Guide Respiration and Provide Inspiratory and Expiratory Images from a Single Navigator-Gated 3D Coronary MRA Acquisition.

Permi Jhooti¹, Jennifer Keegan², Klaus Scheffler¹, David Firmin<sup>2

1</sup>Radiological Physics, University of Basel, Basel, Switzerland; ²CMR Unit, Royal Brompton Hospital, United Kingdom

The mCLAWS technique produces whole heart images in the fastest possible time for a given respiratory pattern and gating window, as well as image datasets at end expiration and end inspiration. The end inspiratory images are generally poorer quality than the end expiratory images because the end inspiratory position is usually more variable and the end inspiratory pause shorter. We have implemented a respiratory biofeedback ‘game’ with a multi-navigator mCLAWS technique to regularise the subjects’ breathing patterns and to enable the acquisition of high quality end inspiratory and end expiratory images from a single whole heart acquisition.

14:30 3674. High Resolution 3D Spiral Coronary Vessel Wall Imaging with >99% Respiratory Efficiency Using Beat to Beat Respiratory Motion Correction: Quantitative Comparison with Navigator Gated 2D Spiral and Turbo Spin Echo Imaging

Andrew David Scott^1,2, Jennifer Keegan, ^1,2, David N. Firmin, <sup>1,2

1</sup>National Heart and Lung Institute, Imperial College, London, Greater London, United Kingdom; ²Cardiovascular Magnetic Resonance Unit, The Royal Brompton Hospital, London, Greater London, United Kingdom

High resolution 3D coronary artery wall imaging potentially enables the assessment of the full 3D extent of a plaque, but is time consuming when used with navigator gating. We compare 3D spiral right coronary artery wall imaging with a highly efficient beat-to-beat respiratory-motion-correction technique using localized tracking of the fat around the artery (99.6% respiratory efficiency) with navigator gated (39% efficient) 2D spiral and 2D turbo spin echo techniques. The techniques were compared quantitatively using vessel wall thickness. The improved respiratory efficiency of the beat-to-beat respiratory-motion-correction technique facilitates high resolution 3D coronary wall imaging within a reasonable duration.

15:00 3675. MR Imaging of Myocardial Scar and Coronary Vein Anatomy in Patients Awaiting Cardiac Resynchronization Therapy Using a High-Relaxivity Contrast Agent.

Simon Graham Duckett¹, Matthew Ginks¹, Benjamin R. Knowles¹, Amedeo Chiribiri¹, Stephen Sinclair¹, Gerry Carr-White², Aldo Rinaldi², Rene Botnar¹, Eike Nagel¹, Reza Razavi¹, Tobias Schaeffter<sup>1

1</sup>Kings College London, London, United Kingdom; ²Guy's and St Thomas's Hospital

As Cardiac resynchronization therapy is becoming more widely available for the treatment of patients with heart failure, there has been increased interest in imaging the coronary sinus and its tributaries. Previous studies using CMR have mainly focused on using intravascular contrast agents (CA), which give no useful information about myocardial scar, and require a separate MR-exam to assess scar and viability. Most of these studies patients with normal left ventricular function have been recruited. We present a single CMR examination imaging the coronary venous anatomy and myocardial scar in patients with HF using a high-relaxivity contrast agent.

Thursday 13:30-15:30 Computer 35

13:30 3676. Non-Invasive Quantification of Atherosclerotic Plaque Inflammation and Neovascularity in a Rabbit Model Using Bright-Blood Dynamic Contrast-Enhanced MRI

John A. Ronald¹, Yuanxin Chen², Kem A. Rogers², William S. Kerwin³, Brian K. Rutt<sup>1

1</sup>Radiology, Stanford University, Stanford, CA, United States; ²Anatomy and Cell Biology, University of Western Ontario, London, Ontario, Canada; ³Radiology, University of Washington, Seattle, WA, United States

Atherosclerotic plaques enriched in inflammatory cells and neovessels are prone to rupture, the life-threatening event underlying heart attacks and stroke. Here we performed the first successful bright-blood dynamic contrast enhanced MR imaging of rabbit atherosclerotic plaques that resemble mid-stage plaques in humans and show that the transfer constant, Ktrans, correlates well with histopathological measures of both macrophage (r=0.4438, p=0.011) and neovessel density (r=0.4186, p=0.027). This is an important extension of this technique, which through necessity has been proven useful for advanced human disease only, and holds promise for its use in assessing the effects of anti-angiogenic/anti-inflammatory therapies in earlier plaques.

14:00 3677. Whole Heart T1 Weighted Coronary Plaque MR Imaging at 3T Using 32channel Cardiac Coils

Hideki Miyagi¹, Hajime Sakuma¹, Shingo Kato¹, Kakuya Kitagawa¹, Motonori Nagata¹, Takase Shinichi¹, Sigfridsson Andreas¹, Masatoshi Miyahara², Mashio Nakamura², Yoshihide Mitani³, Hiroyuki Ohashi<sup>3

1</sup>Department of Radiology, Mie University Hospital, Tsu, Mie, Japan; ²Department of Cardiology, Mie University Hospital, Tsu, Mie, Japan; ³Department of Pediatrics, Mie University Hospital, Tsu, Mie, Japan

Whole heart 3D T1-weighted TSE images were acquired with 3T MR imager and 32-channel cardiac coils in 10 patients with Kawasaki disease who had coronary artery aneurysms and 5 patients with coronary artery disease (CAD). Hyperintense coronary plaque (HIP) was observed in 5 of 10 patients with Kawasaki disease and 4 of 5 CAD patients. On MDCT and IVUS, HIP corresponded to thrombus along the vessel wall or positive remodeling plaque with ultrasound attenuation. 3T T1-weighted coronary plaque MRI allows for noninvasive screening of HIP in the entire coronary artery tree with an averaged imaging time of < 10 minutes.

14:30 3678. Evaluating Anti-Inflammatory Efficacy of Pioglitazone in a Rabbit Model of Atherosclerosis with Multimodality Imaging

Stephen D. Dickson¹, Esad Vucic^1,2, Claudia Calcagno¹, James HF Rudd¹, James Lin¹, Jessica Mounessa¹, Michelle Roytman¹, Zahi A. Fayad<sup>1,2

1</sup>Radiology, Mount Sinai School of Medicine, New York, NY, United States; ²Medicine, Mount Sinai School of Medicine, New York, NY, United States

Dynamic contrast enhanced (DCE) MRI and F18-fluorodeoxyglucose (FDG) PET/CT was performed on control and pioglitazone-treated atherosclerotic New Zealand White Rabbits at three time points over three months. After three months, treated animals showed decreased MRI contrast agent uptake in plaque as well as decreased FDG signal as compared to controls. Macrophage specific immuno-histochemistry validated anti-inflammatory observations.

15:00 3679. Toward a Novel Implantable Contrast Agent for Enhanced MRI Definition of the Vein Graft Wall: Long-Term Stability Assessment of Gd-DTPA Immobilized Contrast-Enhanced (ICE) MRI

Dimitris Mitsouras^1,2, Praveen K. Vemula, ²³, Peng Yu, ^2,4, Ming Tao, ^2,4, Binh T. Nguyen, ^2,4, Jeffrey Karp, ²³, Keith C. Ozaki, ^2,4, Robert V. Mulkern, ^2,5, Frank J. Rybicki<sup>1,2

1</sup>Dept of Radiology, Brigham and Women's Hospital, Boston, MA, United States; ²Harvard University, Cambridge, MA, United States; ³Dept of Medicine, Brigham and Women's Hospital, Boston, MA, United States; ⁴Dept of Surgery, Brigham and Women's Hospital, Boston, MA, United States; ⁵Dept of Radiology, Children's Hospital, Boston, MA, United States

Nearly half of 500,000 vein grafts implanted annually in the US fail. Although MR has enormous potential to assess remodeling and track disease progression, it is severely limited by excessive scan times required to resolve the graft wall (<1mm thickness). Our long-term goal is the development of an implantable MR contrast agent, immobilized on the vein graft surface ex vivo at the time of operation, used to enhance both the MR signal and tissue contrast available for subsequent imaging. We demonstrate for the first time such long-term signal enhancement using a modified Gd-DTPA complex successfully immobilized on the vein surface.