脑梗死的扩散张量成像与扩散加权成像比较研究

Diffusion tensor imaging and diffusion weighted imaging of cerebral infarction:comparative study

目的 比较脑梗死的扩散张量成像与扩散加权成像的影像表现 ,评价其临床应用价值。方法 本研究包括 40例脑梗死患者。影像检查时间从卒中发病后 11h至 9个月。计算病灶侧与对侧的表观扩散系数 (ADC)、各向异性分数(FA)、各向异性指数 (AI) ,进行配对t检验。结果 急性期和亚急性早期、亚急性晚期病灶在扩散加权图像上呈高信号 ;慢性期病灶表现为低信号和 /或高信号。急性期、亚急性早期病灶ADC平均值 ( 3 .2 2 72± 1.0 12 6)低于对侧 ( 7.8861±0 .5 40 7) ,P <0 .0 0 1。慢性期病灶ADC平均值 ( 11.662 9± 1.42 5 1)高于对侧 ( 7.72 48± 0 .7164 ) ,P <0 .0 0 1。亚急性晚期病灶ADC平均值与对侧相比无显著性差异 ,P =0 .814。各期病灶的FA、AI平均值低于对侧 ,P <0 .0 0 1。结论 扩散加权成像可快速检出急性期和亚急性期责任病灶 ,但ADC图不能准确评价各期脑梗死灶水分子的扩散状态。

Objective To compare and evaluate diffusion tensor imaging (DTI) and diffusion weighted imaging (DWI) in cerebral infarctions. Methods Forty patients were analyzed from 11 hours to 9 months after stroke onset. ADC (apparent diffusion coefficient), FA (fractional anisotropy) and AI (anisotropy index) of the lesions and the contralateral side were calculated and compared with paired t test. Results Lesions of acute and subacute phases were with high signal on DWI images, while chronic lesions were with mixed signal. ADC value of acute and early subacute lesions was lower (3.2272± 1.0126 ) than contralateral side ( 7.8861 ± 0.5407 ), P <0.001. ADC value of chronic lesions was higher (11.6629±1.4251) than contralateral side (7.7248±0.7164), P < 0.001 . There was no significant difference between late subacute lesions and contralateral side, P =0.814. FA and AI of lesions with different phases was lower than contralateral side, P <0.001. Conclusion DWI is useful for detecting acute and subacute lesions. ADC could not reveal the diffusion status of infarctions with different phases. FA and AI could show the decrease of anisotropy in lesions.