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.
Zhang
Haosen
H
Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Gropler
Robert J
RJ
Li
Debiao
D
Zheng
Jie
J
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