Electronic Posters: Cardiovascular

Myocardial Perfusion: Experimental Models & Human Studies

Hall B Monday 14:00-16:00 Computer 32

14:00 3616. A New Quantitative Imaging Biomarker for Identifying Critical Coronary Artery Stenosis with Myocardial BOLD MRI

Sotirios A. Tsaftaris^1,2, Xiangzhi Zhou², Debiao Li^2,3, Rohan Dharmakumar<sup>2

1</sup>Electrical Engineering and Computer Science, Northwestern University, Evanston, IL, United States; ²Radiology, Northwestern University, Chicago, IL, United States; ³Biomedical Engineering, Northwestern University, Evanston, IL, United States

Blood-oxygen-level dependent (BOLD) MRI may be used for detecting myocardial oxygenation changes secondary to coronary artery stenosis (CAS). Under pharmacological stress, areas of the myocardium supplied by a stenotic coronary artery appear hypointense relative to healthy regions in BOLD images. The purpose of this work is to present a fundamentally new approach for visualizing and quantifying regional myocardial BOLD signal changes. This approach, tested in canines, relies on the statistical identification of myocardial pixels affected by CAS, correlates strongly with true flow measurements, and most importantly, leads to a significant increase in sensitivity to microvascular flow changes compared to previous approaches.

14:30 3617. Comparison of Systolic and Diastolic Myocardial Perfusion by Dynamic Contrast Enhanced MRI

Aleksandra Radjenovic¹, John D. Biglands¹, Abdulghani Larghat¹, John P. Ridgway¹, Michael Jerosch-Herold², John P. Greenwood¹, Sven Plein<sup>1

1</sup>School of Medicine, University of Leeds, Leeds, England, United Kingdom; ²Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States

Dynamic contrast-enhanced MRI was performed in 17 volunteers to simultaneously assess systolic and diastolic myocardial blood flow (MBF). At rest transmural MBF estimates were similar in systole and diastole (1.6 ± 0.42 vs 1.7 ± 0.49 ml/g/min, p>0.05). During adenosine-induced hyperaemia, MBF was significantly lower in systole than diastole (4.3 ± 0.93 vs 5.7 ± 1.7 ml/g/min, p < 0.0001). Subendocardial MBF was higher than subepicaridal MBF, apart from systole at stress where this relation was reversed. In conclusion, estimates of hyperaemic MBF differ significantly between systole and diastole, following the expected physiological pattern of preferential diastolic filling.

15:00 3618. Mouse Myocardial First-Pass Perfusion Imaging

Bram F. Coolen¹, Rik PM Moonen¹, Leonie EM Paulis¹, Tessa Geelen¹, Larry de Graaf¹, Klaas Nicolay¹, Gustav J. Strijkers<sup>1

1</sup>Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands

A method that allows myocardial first-pass perfusion measurements in mice is presented. Using a combination of segmented saturation-prepared FISP acquisition and GRAPPA parallel imaging allows a temporal resolution of one image every three heart beats with an acquisition time of less than 16 ms. First-pass perfusion images showed the influx of contrast agent into the myocardium with sufficient temporal resolution to derive semi-quantitative perfusion values. These were found significantly lower in a mouse with myocardial infarction compared to healthy control mice.

15:30 3619. Theory-Based Single-Point T₁ Mapping for Quantitative Analysis of First-Pass Cardiac Perfusion MRI: A Validation Study

Elodie Breton¹, Daniel Kim¹, Sohae Chung¹, Leon Axel<sup>1

1</sup>Research Radiology - Center for Biomedical Imaging, New York University Langone Medical Center, New York, NY, United States

Quantitative analysis of first-pass contrast-enhanced cardiac perfusion MRI requires the signal-time curve be converted to Gd-DTPA concentration-time curve. A theory-based single-point T₁ measurement method has been proposed and validated in phantoms at 1.5T. In this study at 3T, the sensitivity to B₁ variations and blood inflow of the single-point T₁ mapping method was first evaluated depending on its linear or centric k-space trajectory. Then, the centric k-space trajectory T₁ mapping pulse sequence was validated in vivo against a multi-point saturation recovery T₁ measurement method in the left ventricular myocardium and cavity.