Assessment of myocardial oxygen extraction fraction and perfusion reserve with BOLD imaging in a canine model with coronary artery stenosis.
OBJECTIVE
To determine the feasibility of T2-weighted BOLD imaging for estimating regional myocardial oxygen extraction fraction (OEF) and approximating perfusion reserve (MPR) simultaneously in a canine model with moderate coronary artery stenosis.


METHODS
Eight mongrel dogs with moderate coronary artery stenosis underwent BOLD imaging at rest and during dipyridamole-induced hyperemia, using a turbo spin echo (TSE) sequence. Based on a two-compartment model, myocardial OEF(hyperemia) was calculated with the corresponding T2. MPR could be approximated based on Fick's law.


RESULTS
During responsive hyperemia, a regional hypointensity was observed in the abnormally perfused myocardium, reflecting a relatively smaller myocardial T2 increase (3.06% +/- 2.74%, in contrast to 10.19% +/- 4.12% in the normal region). The average OEFs in the normally and abnormally perfused myocardial territories were 0.21 +/- 0.11 and 0.43 +/- 0.12, respectively. For the MPR approximated from the BOLD imaging, a strong correlation (R = 0.9) in the normal myocardium and a good correlation (R = 0.6) distal to the stenosis were obtained compared to microsphere results.


CONCLUSIONS
In a canine model with moderate coronary artery stenosis, TSE-based BOLD imaging can quantitatively estimate the regional OEF(hyperemia) and approximate the MPR, and can distinguish segments perfused by defected coronary artery.
Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Haosen
H
Zhang
Robert J
RJ
Gropler
Debiao
D
Li
Jie
J
Zheng
D000818:Animals; D001810:Blood Volume; D003287:Contrast Media; D003326:Coronary Circulation; D023921:Coronary Stenosis / Q000097:blood* / Q000175:diagnosis* / Q000503:physiopathology; D004176:Dipyridamole; D004195:Disease Models, Animal; D004285:Dogs; D005240:Feasibility Studies; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008863:Microspheres; D010100:Oxygen / Q000097:blood*; D014665:Vasodilator Agents
D003287:Contrast Media; D014665:Vasodilator Agents; D004176:Dipyridamole; D010100:Oxygen