磁敏感加权成像在出血性脑梗死诊断中的初步应用

目的探讨磁敏感加权成像（SWI）诊断出血性脑梗死的临床价值。方法20例亚急性期出血性脑梗死患者分别行常规MRI、扩散加权成像（DWI）和SWI检查，根据图像分析结果比较不同扫描序列所显示的梗死灶内出血灶数目及其阳性检出率；测量SWI序列出血最大层面出血灶面积和T2WI序列梗死灶最大层面的梗死灶面积，并行相关分析；观察SWI序列对梗死灶内静脉血管的显示程度，以及梗死灶以外区域微出血灶的诊断敏感性。结果20例患者SWI序列均显示梗死灶内出血，两名医师共诊断43个出血灶，其中SWI序列显示42个、T1WI序列25个、DWI序列15个、T2WI序列12个；SWI序列阳性检出率与T1WI、T2WI、DWI序列相比，差异具有统计学意义（X^2=51．516，P=0．000）。T2WI序列梗死灶最大层面的梗死灶面积为（18．08±12．47）cm^2，SWI为（5．02±6．27）cm^2，梗死灶面积与出血灶范围之间呈明显正相关（r=0．562，P=0．010）。其中，13例患者SWI序列检出梗死灶以外区域的微出血灶；12例显示梗死灶内小静脉血管分支减少和（或）变细，6例血管增多、增粗和（或）扭曲。结论SWI序列对出血性脑梗死病灶内出血的显示优于常规MRI和DWI序列，并能显示梗死灶内静脉血管的变化及梗死灶以外区域的微出血灶，可作为诊断出血性脑梗死的MRI常规扫描序列。

Preliminary clinical application of susceptibility weighted imaging in hemorrhagic cerebral infarction

Objective To investigate the clinical diagnostic vdlue of susceptibility weighted imaging （SWI） in hemorrhagic cerebral infarction. Methods Twenty patients with subacute hemorrhagic cerebral infarction were examined by 3.0T magnetic resonance imaging （MRI）. Conventional MRI, diffusion weighted imaging （DWI） and SWI were performed simultaneously. The images were analysed, and the extents of infarction and hemorrhage were measured. The positive rate of hemorrhage on SWI was compared with other sequences. The largest areas of hemorrhage between SWI and T2WI were performed with correlation analysis. In addition, the venous within the infarction and the micro-hemorrhage beyond the infarction were also analysed. Results SWI demonstrated all the hemorrhagic lesions （20 cases, 100%）. SWI showed 43 hemorrhagic lesions in 20 patients, while 25, 15, 12 hemorrhagic lesions were detected on T1WI, DWI and T2WI, respectively. The largest extent of infarction was （18.08 ± 12.47） cm2 and the extent of hemorrhage was （5.02 ± 6.27） cm2 in 20 patients. There was strong correlation （r = 0.562, P = 0.010） between the extents of infarction and hemorrhage. SWI also showed hemorrhagic lesions outside infarction in 13 patients. Less or thinner venous branches were found in 12 patients, while more, larger or tortuous venous branches were found in 6 patients. Conclusion SWI is much better for hemorrhagic cerebral infarction than conventional MRI sequences, and can discover small hemorrhage focus out of cerebral infarction. SWI should be used as a routine examination for diagnosis of hemorrhagic cerebral infarction.