磁共振弥散加权成像对急性皮层下脑梗塞的评价

目的 研究磁共振弥散加权成像（DWI）诊断急性皮层下脑梗塞的准确性以及对急性与非急性皮层下脑梗塞的鉴别诊断。材料与方法 对32例临床诊断为急性皮层下脑梗塞的患者和20例对照者在不同时间内进行常规MRI检查和弥散加权MRI检查，并用盲法进行对照观察。对所有病例的病变部位均按神经解剖进行准确定位并与患者的症状、体征相联系。结果 DWI诊断急性皮层下脑梗塞的敏感性、特异性及准确性分别为97％、95％和96％。32例中有3例常规MRI检查未发现急性梗塞性。另20例常规MRI检查均显示为多发梗塞，而DWI只显示单个急性病灶，且患者的症状、体征与DWI上显示的病灶相符。结论 DWI对诊断急性皮层下脑梗塞有很高的准确性，能发现常规T2WI不能发现的早期脑梗塞，并能鉴别急性与非急性梗塞。

Acute Subcortical Cerebral Infarction: Evaluation with Diffusion Weighted MR Imaging

Objective　To determine the accuracy of diffusion-weighted (DW) MR imaging for the detection of acute subcortical cerebral infarction, and the efficacy of DW MRI in differentiating acute from non-acute subcortical infarctions when multiple infarction lesions were demonstrated on conventional MRI.　Materials and Methods　Thirty-two patients with clinically-diagnosed acute subcortical infarction and 20 control subjects were scanned with both conventional and DW MRI within 2～72 hours after the onset of symptoms. All the images were double-blindly reviewed and compared. In all cases, the neuroanatomic locations of the lesions were precisely determined, and an experienced neurologist judged if the location of the lesion seen on MRI was in agreement with the patient's symptoms and signs.　Results　The sensitivity, specificity and accuracy of DW MRI in diagnosing acute subcortical infarction were 97%, 95% and 96%, respectively. Of 32 patients, the acute infarction was not detected on conventional MRI in 3. Of 20 patients who demonstrated acute lesions as well as multiple other subcortical lesions on conventional MRI, all were proved to have only one lesion being acute on DW MRI which was correlated with patient's clinical symptoms and signs.　Conclusion　DW MRI is of high accuracy for diagnosing subcortical infarction and detecting early infarction lesions which are difficult to be displayed on conventional MRI, and is very helpful in differentiating acute from non-acute lesions.