磁共振扩散加权成像在急性脑梗死诊断中的应用

Study on application of diffusion-weighted imaging in the diagnosis of acute cerebral infarction

【目的】评价磁共振扩散加权成像（DWI）在急性脑梗死诊断中的临床价值。【方法】选取呈卒中样发病的患者66例。行头颅CT检查排除脑出血后,经临床和MRI确诊为急性脑梗死的患者56例,根据行MR检查距发病时间长短将患者分成6 h内,6～24 h,24～48 h,48～72 h 4个组。选取病灶中心和健侧相应部位5×5像素大小区域为各自的感兴趣区,测定各自的ADC值,并计算rADC值。【结果】56例患者均在DWI上显示与临床症状、体征相符的病灶。病灶在DWI上具有较高的信号强度和清晰度。36例患者经DWI证实在T2WI上显示的部分高信号病灶为陈旧性。10例呈卒中样发病的非急性脑梗死患者DWI上均未显示典型高信号影。56例患者病灶中心的ADC值均低于健侧相应部位（配对t检验,P〈0.01）;不同时间段的rADC差别无统计学意义（单因素方差分析,F=2.055,P=0.118）。【结论】DWI在脑梗死超急性期和急性期均具有很高的敏感性,在对呈卒中样发病的患者鉴别诊断方面具有较高的应用价值。

[Objective] To evaluate the clinical value of DWI in the diagnosis of acute cerebral infarction. [Methods] A total of 66 patients with strokelike onset symptoms were collected. Exclusion of hemorrhage by CT scanning before MR imaging, acute cerebral infarction was diagnosed with clinical manifestation and MRI in 56 cases. The patients were divided into four groups according to time： 6 h, 6 ～ 24 h, 24 ～ 48 h and 48 ～ 72 h. Region of interest （ROI） of 5 ～ 5 pixel was selected in the center of lesions. Corresponding contralateral brain region and the ADC value and rADC were calculated. [Results] Lesions corresponding with clinical symptoms and physical signs were detected on DWI in 56 cases. The lesions on DWI showed higher signal intensity and distinctness than those on T2 WI. Chronic lesions with high signal intensity on T2 WI were confirmed by DWI in 36 cases. Typical high signals on DWI were not found in 10 cases with stroke and had no cerebral infarction. The ADC value of lesions was lower than that of the contralateral location （Paired samples t test, P〈0.01） in 56 cases. The difference of rADC was not statistically significant （ANOVA, F= 2.055, P = 0. 118）. [Conclusions] DWI is a more reliable imaging method than conventional MRI in the detection of ischemic lesions in acute stroke patients （ 〈 72 hours） and is useful in the differential diagnosis of patients with strokelike onset symptoms.