磁共振增强扫描对急性心肌梗塞诊断的研究

The Study of Diagnostic Ability of AMI with Gd-DTPA-Enhanced MRI

目的:评价MRI诊断急性心肌梗塞(AMI)的价值。材料和方法:21例首次患AMI者和5例无心脏病的志愿者进行了MRI自旋回波T_1加权、T_2加权和增强扫描。结果:(1)急性梗塞心肌征在F_2加权像上呈高信号强度(SI),且梗塞心肌与正常心肌分界清晰;在T_1加权上呈低或等SI;局限性左室壁变薄12例;室壁瘤1例;(2)梗塞心肌平均强化92.71±25.71％,明显高于病例组和对照组的正常心肌(P<0.001);且信号强度比在增强后明显高于增强前;(3)T_2加权像上伪影多信噪比低,增强扫描图像清晰,病灶边界更清楚;(4)增强扫描图像上可较准确地测定梗塞灶的重量。结论:MRI特别是MRI增强扫描可用来分析和诊断AMI。

Purpose:To evaluate the diagnostic value of MRI in acute myocardial in farction(AMI). Materials and methods: 21 patients (male 17, female 4) with first AMI and 5 volunteers (control group) without heart disease were studied. All patients and control group underwent MRI SE T1-,T2-weighted sequence and enhanced scan. Results: The main appearance of AMI on MRI were as follows: (1)All infarcted myocardium appeared high signal intensity (SI) in T2-weighted images on which infarct and normal myocardium were de-mercated clearly, low or equal SI in T1-weighted images. Local thinned left ventrical wall were shown in 12 cases and ventricular aneurysm was seen in 1 case. (2)The infarct areas of all patients were enhanced markedly with average enhancement ratio 92. 71±25. 71 % It was obviously higher than that of normal myocardium of patients and control group (both P <0.001). SI ratio of enhanced images was apparent higher than that of precontrast images. (3)Enhanced-images were superior to T2-weighted images in imaging quality and signal-to-noise ratio. (4)Enhanced-MRI can be used to measure the ifarct size. Conclusion: MRI, es-pically enhanced-MRI, can diagnose and analyse AMI.