DWI在超急性CI的诊断及不同时期CI信号分析中的应用

目的探讨MR弥散加权成像(DWI)对腔隙性超急性脑梗塞诊断的敏感性及其限度,梗塞灶的演变过程中DWI、T2WI、T1WI信号的变化规律.方法美国GE公司signa 1.5Tsys # TwinExct MR成像仪,8通道相阵控头部线圈,均平扫,每例常规MRI及DWI扫描,SE序列横断面T1WI及T2WI,怀疑脑干病变加扫矢状及冠状T2WI,DWI采用单次激发SEEPI序列横断面扫描.结果158例脑梗塞全部为脑干、基底节区、辐射冠区等脑深穿动脉供血区的腔隙性梗塞灶,其中超急性脑梗塞57例;急性脑梗塞31例;亚急性脑梗塞40例;慢性脑梗塞30例.此外2种或2种以上不同时期病灶并存89例.患行颅脑单次激发回波平面弥散加权MRI(DWI)和常规MR扫描,结果:超急性脑梗塞、急性脑梗塞和亚急性脑梗塞DWI均表现为高信号.57例超急性脑梗塞DWI除4例外均表现为高信号,T2WI有10例见小片状稍高信号,T1WI均未显示病灶.31例急性脑梗塞DWI及T2WI均表现为高信号,T1WI有8例在相同部位见稍低信号,40例亚急性脑梗塞DWI及T2WI均为高信号,T1WI均为低信号.慢性脑梗塞边界清楚,无占位效应,DWI低或等信号,T1WI均为低信号,T2WI均为高信号.随着病灶由急性向慢性的转变,T1WI信号逐渐降低,T2WI信号逐渐升高,DWI信号由高信号变为低信号. 结论DWI对超急性脑梗塞较常规MRI具有更高的敏感性,并能区分急性与非急性期脑梗塞.对2种或2种以上不同时期并存的病灶有较好的检出率,发现与当前症状及体征一致的梗塞灶.

Application of DWI in the diagnosis of superacute cerebral infarction and differentiation with T1WI and T2WI in different stages of cerebral infaction

Objective To determine the sensitivity of diffus ion weighted MR imaging (DWI) for the detection of superacute cerebral infarcti on and its limitation. Methods 158 patients with cerebral infarct ion (57superacute,3 lacute,40subacute,30chronic),they were imaged with both conv entional MRI(T1WI, T2WI) and single shot echoplanar diffusion weighted MRI(DWI). Results Superacute, acute and subacute cerebral infarctions all showe d hypersignal on DWI,43 case superacute cerebral infarctions were only depicted on DWI,except 10 cases were shown on T2WI,but not shown on T1WI. The acutes all showed hypersignal on DWI and T2WI,8 cases on TlWI were shown hyposignal. Subac u te infarction shown on DWI and T2WI were hypersignal ,on T 1 WI shown hyposignal . All chronic infarctions shown on conventional MRI and DWI,on DWI and TlWI wer e hyposignal;on T2WI was hypersignal. Conclusion DWl has higher sensitivity for acute especially superacute cerebral infarction then conventiongal MRI and can dif fremtiate acute from nonacute lesions and More then two lesions(multi-infarctions),DWI can observe new infarction.