Electronic Posters: Cardiovascular

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.