延时增强MRI与病理对照评价猪心肌梗死模型失活心肌

Assessment of myocardial viability with delayed-enhanced MRI in ischemic swine models:compared with pathological findings

目的探讨延时增强MRI(DE-MRI)检测失活心肌的价值。方法利用15只滇南小耳猪制作急性心肌梗死模型,并分别于24h、72h、1周行心脏DE-MR检查,观察高信号部位、节段数与透壁程度;之后行TTC染色和病理检查。结果10只心肌梗死模型制作成功,术前DE-MR检查未见异常,术后检测到30个异常高信号心肌节段,其检测节段数及部位与TTC染色相比差异无统计学意义;对梗死心肌节段透壁程度的判断,两者相关且存在一致性(Chi-Squaretest,P<0.05;K>0.75),但对判断透壁程度,DE-MRI所显示高信号透壁程度分级高于TTC染色(McNemartest,P<0.05)。结论DE-MRI能准确检测梗死心肌,并能清楚描述梗死心肌节段的透壁程度;但应注意急性期梗死区有被"放大"可能。

Objective To investigate the value of the delayed-enhanced MRI （DE-MRI） in detecting the myocardial infarction （MI）. Methods A total of 15 pigs were used to make the acute MI models, and then ten successful models underwent DE-MRI at 24 h, 72 h and 1 W, respectively. The hyperenhanced regions and the numbers of segments with MI as well as their transmural extent were observed. After MR examination, 2, 3, 5-triphenyltetrazolium chlorid （TTC） staining and pathological examination were performed. Results Ten MI models were made, and no abnormal signals were found with pre-operative DE-MRI. A total of 30 hyperenhanced segments were observed with DE-MRI after operation, and no difference was found between DE-MRI and TTC staining. In the judging the extent of MI, DE-MRI was correlative with TTC staining （Pearson Chi-Square, P〈0.05 ; K〉0.75）, but the results of two methods was different （McNemar test, P〈0. 05）. The transmural extent judged with DE-MRI was higher than with TTC staining. Conclusion DE-MRI is an excellent tool for detecting MI and can clearly demonstrate the transmural extent of MI. Special attention should be paid to the areas of acute MI as it may be ＂zoomed＂.