急性缺血再灌注后心肌微血管床损伤的心脏MR影像研究

目的应用心肌首过灌注MR影像分析单支冠状动脉闭塞和多支冠状动脉狭窄无闭塞所造成的心肌微血管床闭塞差异.方法33例患者临床诊断为急性心肌梗死,其中15例为单支冠状动脉完全闭塞,18例为多支冠状动脉狭窄.发病后6～12周进行心脏MR影像检查.结果11例单支冠状动脉完全闭塞和4例多支冠状动脉狭窄患者的左心室内膜下心肌内存在首过灌注缺损区,前者显著多于后者(P＜0.01).心肌首过灌注缺损区域的信号强度峰值和信号增加的最大斜率显著小于灌注正常心肌(P＜0.05).结论心肌灌注首过时相影像能够显示急性缺血再灌注损伤所导致的心内膜下微血管床闭塞.单支冠状动脉闭塞的患者较多支冠状动脉狭窄的患者更容易发生心内膜下的微血管床闭塞.

MRI study of myocardial microvascular obstruction after acute ischemic reperfusion

Objective To evaluate the myocardial microvascular obstruction induced by occlusion of single coronary artery (OSCA) and stenosis of multi-coronary arteries (SMCA) using first-pass perfusion cardiac MRI. Methods We studied 33 patients who had acute myocardial infarct and received emergency coronary angiography and angioplasty. Coronary angiogram confirmed that 15 patients had complete occlusion of the single coronary artery and 18 patients had multi-coronary artery stenosis without occlusion. Cardiac MRI (CMRI) exam was performed at 6-12 weeks after diagnosis. Results CMRI demonstrated that 15 patients had first-pass perfusion defect in the endomyocardium. The signal intensity (SI) of the perfusion defect was significant lower than that in the normal myocardium. The maximal slope of SI showed that the there were 11 patients with occlusion of the single coronary artery and 4 patients with stenosis of multi-coronary arteries. Conclusion CMRI can show the microvascular obstruction limited in the region of endomyocardium. CMRI suggests that the occlusion of the single coronary artery may induce more severe myocardial microvascular obstruction than the stenosis of multiple coronary arteries.