MR DWI及ADC值在急性脑梗死诊断中的应用价值

目的评价磁共振扩散加权成像（DWI）和表观扩散系数（ADC）在急性脑梗死诊断中的临床价值。方法选取临床上拟诊为脑梗死患者186例进行常规MR扫描及DWI检查，根据发病时间分成超急性期（〈6h）、急性期（6～72h）、亚急性期（3～7d）3个组。测定各组梗死灶ADC值及健侧ADC值，并计算相对ADC（rADC）。结果超急性期、急性期、亚急性期梗死灶ADC值均低于健侧相应区域（配对t检验，P〈0．01）；超急性期、急性期及亚急性期病例之间rADC有统计学差异（单因素方差分析，F=7．663，P=0．001）。结论DWI在脑梗死超急性期、急性期、亚急性期均具有很高的敏感性，各期梗死灶rADC值有时间相关性，对脑梗死的准确分期有重要价值。

Evaluation of MR DWI and ADC in the diagnosis of acute cerebral infarction

Objective To evaluate the clinical value of MR diffusion weighted imaging （DWI）and apparent diffusion coefficient （ADC）in the diagnosis of acute cerebral infarction.Methods A hundred and eithty-six patients with clinically suspected acute cerebral infarction underwent conventional MRI,DWI and ADC examinations after onset of clinical symptoms.All patients were divided into below three groups according to the course of disease：hyperacute stage（〈6 h）,acute stage（6-72 h）,subacute stage （3-7 d）.The ADC vaues in the infarct foci and relative ADC （r ADC）values in the intact side were calculated for each case.Results The ADC value of cerebral ischemic regions in hyperacute,acute and subacute stage was significantly lower than that of intact side tissue in corresponding stages （Paired samples t test,P〈0.001）.The rADC value of subacute stage was significantly higher than that of hyperacute and acute stage （ANOVA,F= 7.663,P〈0.001）.Conclusion DWI is a more reliable imaging method than conventional MRI for detecting the ischemic foci in acute stroke patients（〈72 h）.There is positive correlation between rADC and the course of disease so that rADC values can accurately differentiate the different stages of cerebral infarction.