MRI检测活性心肌及其与冠状动脉造影、SPECT和PET对比研究

目的：分析MRI对冠心病患者心肌活性的诊断价值并与冠状动脉造影、SPECT和PET结果对比。方法：应用MRI对21例临床符合冠心病的患者进行检查，并将结果与冠状动脉造影、SPECT和PET检查结果对照。结果：MRI静息心肌灌注扫描检出的缺血节段比狭窄冠状动脉的供血节段少但无统计学差异（Z=-1.732，P=0．083）；比SPECT心肌灌注扫描检出的缺血节段多且有统计学差异（Z=-3．691，P=0．000）。SPECT心肌灌注扫描检出的缺血节段比狭窄冠状动脉的供血节段少且有统计学差异（Z=-3．029，P=0．002）。以正电子发射断层显像（PET）结果为标准，MR延迟扫描检测活性心肌的灵敏度为97．6％，特异度为98．4％，总符合率为98．2%，Kappa值为0．953。MR延迟扫描检出的活性心肌比PET检出的少但无统计学差异（Z=-0．209，P=0．835）。结论：MR心脏检查清晰显示心肌梗死的位置、程度和附壁血栓情况，并可对左室室壁运动进行直观显示。常规SPECT心肌灌注显像由于空间分辨率低明显低估心肌缺血范围。心肌PET显像空间分辨率低，无法显示心肌梗死的透壁程度，且不能直观显示室壁运动情况。

MR imaging in detection of myocardial viability: a comparison with coronary angiography, SPECT and PET

Objective To evaluate the diagnostic value of myocardial viability in patients with coronary artery disease (CAD) by using MRI, coronary angiography, 201Tl single-photon emission computed tomography (SPECT) and 18F-fluorodeoxyglucose positron emission tomography (PET). Methods Twenty-one CAD patients underwent MRI, the result of MR scanning was compared with that of coronary angiography, SPECT and PET. Results Ischemia segments detected by rest myocardial perfusion MR scanning were less than blood supply segments of stenosis coronary artery, but had no statistic difference (Z=-1.732, P=0.083) and significantly more than which detected by SPECT (Z=-3.691, P=0.000). Ischemia segments detected by SPECT significantly were less than blood supply segments of stenosis coronary artery (Z=-3.029, P=0.002). Using PET as standard, the sensitivity, specificity and total coincidence of delayed enhancement MRI in determination of viable myocardium were 97.6%, 98.4% and 98.2%, respectively. Kappa value of delayed enhancement MRI and PET was 0.953. Viable segments detected by delayed enhancement MRI were less than which detected by PET but had no statistic difference (Z=-0.209, P=0.835). Conclusion Cardiac MRI can combine morphology, function and perfusion to determine viable myocardium, delineate the location and extent of necrosis myocardium and mural thrombosis clearly, demonstrate wall motion of left ventricular directly and measure function of left ventricle. Conventional SPECT underestimate myocardial viability because of its low spatial resolution. PET has low spatial resolution which ca not distinguish transmural necrosis from subendocardial necrosis and can't demonstrate wall motion of left ventricular directly.