Myocardial intensity changes associated with flow stimulation in blood oxygenation sensitive magnetic resonance imaging.
Functional magnetic resonance imaging exploits deoxygenated blood as an endogenous source for contrast in assessing local changes in tissue perfusion. Intrinsic changes in myocardial signal intensity were measured during dipyridamole induced coronary vasodilatation with T2*-weighted echo planar MRI in healthy volunteers. Concurrently, changes in flow velocity in the left anterior descending coronary artery were measured using a time-of-flight method. Dipyridamole infusion produced 14 +/- 6% increase in myocardial signal intensity (n = 7). Temporal profile of the myocardial signal intensity changes correlated well with the augmentation of coronary flow velocity. The data are consistent with the concept that changes in myocardial deoxyhemoglobin content due to altered flow result in changes in magnetic susceptibility that can be detected on T2*-weighted MR images.
Niemi
P
P
Department of Radiology, Massachusetts General Hospital, Charlestown, USA.
Poncelet
B P
BP
Kwong
K K
KK
Weisskoff
R M
RM
Rosen
B R
BR
Brady
T J
TJ
Kantor
H L
HL
D000328:Adult; D001783:Blood Flow Velocity / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D003287:Contrast Media; D003326:Coronary Circulation / Q000187:drug effects; D003331:Coronary Vessels / Q000187:drug effects; D004176:Dipyridamole / Q000494:pharmacology; D017352:Echo-Planar Imaging / Q000379:methods*; D006321:Heart / Q000033:anatomy & histology*; D006339:Heart Rate / Q000187:drug effects; D006346:Heart Septum / Q000378:metabolism / Q000473:pathology; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D006940:Hyperemia / Q000378:metabolism; D007089:Image Enhancement / Q000379:methods*; D009206:Myocardium / Q000378:metabolism; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption; D014665:Vasodilator Agents / Q000494:pharmacology
D003287:Contrast Media; D006454:Hemoglobins; D014665:Vasodilator Agents; D004176:Dipyridamole; C100003:deoxyhemoglobin; D010100:Oxygen