联合应用DWI和MRA在急性脑梗死中的诊断价值

Combined diffusion-weighted imaging and magnetic resonance angiography in the diagnosis of acute cerebral infarction

【目的】探讨联合应用DWI和MRA对急性脑梗死进行影像学评价的临床价值。【方法】经临床和影像学确诊为急性脑梗死的患者42例，均行DWI检查，其中30例患者同时行MRA检查。根据行MR检查距发病时间长短将患者分成6h内，6～24h，24～48h，48—72h4组。选取病灶中心和健侧相应部位5X5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。描述DWI上病灶与MRA血管异常之间的关系。【结果】42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，病灶侧的ADC值均低于健侧（P〈0．01）。30例MRA中，21例（70．0％）发现血管狭窄或闭塞，其中12例大面积病灶的血管病变阳性率为100％。DWI在前后循环上显示病灶解剖定位均与MRA上血管异常解剖定位有很好的一致性。【结论】DWI在脑梗死超急性期和急性期均具有很高的敏感性，MRA能很好的显示颅内大血管的狭窄和闭塞，DWI所显示病灶与MRA上血管异常有很好的相关性。

[Objective] To explore the clinical value of DWI and MRA on imaging evaluation of acute cerebral infarction. [Methods] A total of 42 patients diagnosed as acute cerebral infarction by clinical manifestation and medical imaging were collected. DWI was performed in all and MRA was performed in 30 of them. The patients were divided into four groups according to time： 6h （n=14）, 6-24 h （n=9）, 24-48 h （n=7） and 48-72 h （n= 12）. Region of interest （ROI） of 5 × 5 pixel was selected in center of lesions and the corresponding contralateral brain region and ADC value and rADC were calculated. The relationship between the position of lesions on DWI and the anatomy of abnormal vessels on MRA were studied. [ Results] 42 patients were detected the lesions on DWI which were accorded with clinical symptoms and physical signs. The lesions in DWI showed higher signal intensity and distinctness than those on T2WI. The ADC value of lesions was lower than that of the contralateral location （P 〈 0.01）. In 21 of 30 patients, MRA showed abnormality and other patients were normal. All large area lesions on DWI in 12 patients showed abnormal cranial vessels. The position of lesions on DWI in anterior and posterior circlation was accorded with the anatomy of abnormal vessels on MRA. [Conclusions] DWI is a more reliable imaging method than conventional MRI in detecting ischemic lesions in acute stroke patients （ 〈 72 h）. MRA could demonstrated stenosis or occlusion of main vessels. Anatomical position of lesions on DWI was consistent with vascular abnormality on MRA.