Assessment of regional myocardial blood flow with myocardial contrast echocardiography: an experimental study.
OBJECTIVE
The aim of this study was to verify the accuracy of using myocardial contrast echocardiography (MCE), to quantify regional myocardial blood flow (MBF), and to evaluate myocardial viability in comparison to that measured by radiolabeled microsphere and pathologic examination.


METHODS
Epicardial MCE was obtained in five myocardial ischemic dogs with constant microbubble intravenous infusion. After the video intensity (VI, y) versus pulsing interval plots derived from each myocardial pixel were fitted to an exponential function: y = A(1 - e(-beta t)), the MBF was calculated as the product of A (microvascular cross-sectional area or myocardial blood volume) and beta (mean myocardial microbubble velocity). The MBF was also obtained by radiolabeled microsphere method.


RESULTS
The MBF derived by radiolabeled microsphere method in the normal, ischemic, and infarcted region was 1.5 +/- 0.3, 0.7 +/- 0.3, and 0.3 +/- 0.2 ml/min per gram, respectively; P < 0.01. The product of A and beta in those regions was 52.5 +/- 15.1, 24.4 +/- 3.9, and 3.7 +/- 3.8, respectively; P < 0.01. The normalized product of A and beta correlated well with normalized MBF (r = 0.81, P = 0.001).


CONCLUSIONS
Our initial study demonstrated that MCE has an ability to assess MBF in ischemic myocardium in the experimental model. It may provide a potential capability to detect viable myocardium noninvasively after total persistent coronary occlusion in the clinical setting.
Zhang
Wen Zhu
WZ
Department of Cardiology, Nanfang Hospital, The First Military Medical University, Guangzhou, People's Republic of China.
Zha
Dao Gang
DG
Cheng
Guan Xun
GX
Yang
Shao Qin
SQ
Huang
Xiao Bo
XB
Qin
Jian Xin
JX
Liu
Yi Li
YL
D000818:Animals; D003326:Coronary Circulation / Q000502:physiology; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000503:physiopathology; D004285:Dogs; D004452:Echocardiography; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology; D008297:Male; D008854:Microscopy, Electron; D008863:Microspheres; D023421:Models, Animal; D008955:Models, Cardiovascular; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging / Q000503:physiopathology; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000473:pathology* / Q000648:ultrastructure*; D012039:Regional Blood Flow / Q000502:physiology; D013223:Statistics as Topic