不同期相脑梗死在扩散加权成像中的信号特征及临床应用

目的:探讨在不同期相脑梗死中DWI(核磁共振扩散加权成像)及ADC图(表观弥散系数图像)的信号特点及其成像技术对脑梗死的应用价值。方法:对54例脑梗死患者,应用SE-T1WI、FSE-T2WI、T2-FLAIR、DWI序列进行横断位扫描,及ADC图像重建,并按发病时间分为超急性期、急性期、亚急性期和慢性期,观察并测量DWI图像及ADC图在不同期相脑梗死中的信号强度和ADC值的大小。结果:对于超急性期和急性期的脑梗死病灶,其DWI信号明显高于正常脑组织(P<0.05),其ADC值则低于正常脑组织(P<0.05),二图对其均有很高的显示度;对于亚急性期病灶,其DWI信号高于正常脑组织(P<0.05),其ADC值与正常脑组织信号差别不大(P>0.05),DWI可以显示病灶;对于慢性期病灶,DWI信号等或稍低于正常脑组织,对病灶显示意义不大(P>0.05),而ADC值高于正常脑组织(P<0.05),可以显示病灶区域。结论:DWI和ADC图对超急性期、急性期脑梗死都有很大的诊断意义,DWI对亚急性期病灶有一定显示度,ADC图对慢性期梗死灶也有一定诊断意义。

Signal characters of cerebral infarction in different stage and clinical application of magnetic resonance diffusion weighted imaging

Objective： To study the value of diffusion-weighted images （DWI） and apparent diffusion coefficient map （ADC map） in the diagnosis of cerebral infarction in different stage. Methods： By different onset time, 54 cases with cerebral infarction were divided into superacute, acute, subacute and chronic stages . SE-T1WI, FSE T2WI, T2-FLAIR and DWI were performed on all cases, then the ADC map calculated from DWI. The signal intension of DWI were analysed and ADC values of ADC map were measured of different stage of cerebral infarction. Results： As for superacute and acute cerebral infarction, all focuses obviously showed higher signal in DWI （ P 〈0.05） and lower ADC value （ P 〈0.05） than those of normal cerebral tissue, all focuses could be showed exactly; as for subacute cerebral infarction, higher signal in DWI （P〈 0. 05 ） could be found, the ADC value was almost equal to that of normal cerebral tissue （ P 〉0.05）, all focuses could be showed by DWI~ as for chronic stage, it was not significant to show focuses as they were isointensity or unremarkable hypointensity on DWI（ P 〉0.05）. The ADC value was higher than that of normal cerebral tissue（ P 〈0. 05）, all focuses could be showed by ADC map. Conclusion： Cerebral infarction in superacute and acute stage can be diagnosed accurately by DWI scanning and ADC map. The subacute cerebral infarction can be showed by DWI. ADC map is of high value in diagnosing cerebral infarction for chronic stage.