磁敏感加权成像显示急性脑梗死病灶内静脉数目变化和脑实质内微出血的临床价值

目的 探讨磁敏感加权成像对急性脑梗死病灶内静脉数目变化和梗死灶外脑实质内微出血的临床价值.方法 回顾性分析46例急性脑梗死患者的磁共振扫描影像资料,包括常规MRI平扫、扩散加权成像（DWI）、MRA和磁敏感加权成像（SWI）.对SWI原始图像后处理得到最小信号强度投影图（minimum intensity projection,MinIP）.结果 46例急性脑梗死病变在常规MRI序列呈稍长T1稍长T2信号,DWI呈高信号.MRA显示25例一侧大脑中动脉狭窄或闭塞.SWIminIP图示25例急性脑梗死病灶内静脉数目较对侧相应区域减少.常规平扫检出梗死灶外脑实质内出血6例,检出率为13.0％;SWI检出梗死灶外脑实质内出血和微出血19例,检出率为41.3％.结论 急性脑梗死病灶内静脉数目减少间接反映梗死灶的氧代谢率减低.磁敏感加权成像比常规MRI平扫对脑内出血和微出血的显示更敏感.

The Clinical Application Value of Susceptibility Weighted Imaging in Veins Changes of Acute Cerebral Infarction Lesion and Hemorrhage Out of the Lesion

Objective To investigate the clinical application value of susceptibility weighted imaging（SWI） in veins changes of acute cerebral infarction lesion and microhemorrhage out of the lesion. Methods Forty - six acute cerebral infarction（ACI） patients＇imaging data including conventional MRI, DWI, MRA and SWI were retrospectively reviewed. The raw data of SWI were postprocessed to gain SWI minimum intensity projection （MinIP）. Results 46 cases of ACI in conventional MRI sequences showed longer T1 and longer T2 signal, DWI showed high signal. MRA showed 25 cases the side of middle cerebral artery occlusion. SWIminIP showed 25 cases decreased veins of the lesion. Hemorrhage and microhemorrhage were confirmed by two methods, it is detected 19 cases by SWI , and 6 cases by conventional MRI. Both hemorrhage detection rate using paired chisquare test （ P = 0. 000 ）. The positive rate of SWI and conventional MRI detecting hemorrhage and microhemorrhage is 41.3 %, 13.0%, respectively. Conclusion Veins decreased of ACI lesion indirectly reflect reduced oxygen metabolism. SWI is more sensitive in detecting hemorrhage and microhemorrhage conventional MRI sequences, especially in detecting microhemorrhage.