急性心肌梗塞的MR灌注成像及延迟扫描:实验研究并与病理对照

MR perfusion imaging and delay scanning of acute myocardial infarction: an experimental study with pathological correlation

目的探讨首过MR(磁共振)灌注成像和延迟扫描对预测存在梗塞风险的心肌和评价梗塞面积的价值。方法在导管法冠状动脉造影的指导下将凝胶海绵注射入11只比格犬的左前降支(left anterior descending,LAD)的中部阻塞血管,首过法MR灌注成像在LAD阻塞后30min内进行,3d后行MR增强延迟扫描。对心肌切片采用2,3,5,氯化三苯基四氮唑(triphenyltetrazolium chloride,TTC)染色,比较MR延迟扫描和TTC染色切片上心肌梗塞的面积。结果3只犬制作心肌梗塞模型过程中死亡,8只犬存活并完成实验。MR灌注成像30min内即显示阻塞血管供血区低灌注。延迟扫描和TTC染色切片上测量心肌梗塞大小分别为0.281±0.056和0.307±0.070,两者间有相关性(r=0.86,P=0.008)。结论MR灌注成像和延迟扫描可以预测存在梗塞风险的心肌和评价梗塞面积,进而指导临床干预和判断预后。

Objective To investigate the value of first passing MR perfusion imaging and delay enhanced MR imaging in predicting myocardium at risk of infarction and assessing the infarct size. Methods The left anterior descending （LAD） of coronary artery was occluded at the middle portion by injection of gel sponges under the guide of catheter angiography in 11 beagles. First passing MR perfusion was performed within 30 min after the coronary artery obstruction. Delay enhanced MR imaging was conducted 3 days late. The heart slices were stained by triphenyltetrazolium chloride （TTC）. Infarct size measured by delay enhanced MR images and TTC staining slices was compared. Results Eight dogs survived and successfully completed the experiment while 3 dogs died during the process of inducing acute myocardial infarction. MR perfusion imaging revealed that low perfusion areas were supplied by coronary artery occlusion within 30 rain after the blood supply was cut off. The infarct size measured by delay enhanced MR images and TTC staining slices was 0.281 ±0.056 and 0.307 ± 0.070 respectively, showing a good correlation （r = 0.86, P = 0.008）. Condusion MR perfusion imaging and delay enhanced MR imaging are useful for indicating myocardium at risk of infarction and assessing infarct size so as to guide clinical management and predict prognosis.