磁敏感加权成像用于诊断非典型蛛网膜下腔出血的初步研究

Diagnosis of Atypical Subarachnoid Hemorrhage with Susceptibility-Weighted Imaging

目的分析非典型蛛网膜下腔出血(atypical subarachnoid hemorrhage,aSAH)在磁敏感加权成像(suscepti-bility-weighted imaging,SWI)上的影像表现,探讨SWI技术在aSAH的临床应用价值。方法分析22例接受CT和MRI(含SWI)检查并最终确诊为aSAH的患者。由两名工作10年以上具有高级职称的影像学医师分析患者CT和MRI(含SWI)数据,以判断蛛网膜下腔是否存在aSAH,并分析其影像表现。结果 SWI总共确定aSAH出血区域共47个,其中16个(34.04%)位于凸面或半球间,19个(40.43%)位于脑池,6个(12.77%)是小脑幕的蛛网膜下腔出血,6个(12.77%)位于脑室内。在脑沟或者脑池内,aSAH在SWI上表现为低信号(出血)周围环绕脑脊液信号,在较浅脑沟内可形成"三角"征;与静脉的平滑边界相比,蛛网膜下腔出血边界较粗糙,信号略显不均。aSAH在脑室内可呈现"液-液平面"。结论在SWI图上,aSAH可通过其信号和独特的形态得以确认,SWI能够提供较CT和常规MRI更多的信息显示出血少量的aSAH。

Objective To analyze susceptibility-weighted imaging （SWI） findings of atypical subarachnoid hemorrhage （aSAH）,and to investigate the clinical value of SWI in the diagnosis of aSAH. Methods CT and MRI data of 22 patients with aSAH were analyzed by 2 senior neurora- diologists to decide whether there was aSAH in the anatomical parts of subarachnoid space. Re- sults Forty-seven areas of aSAH were identified by SWI. Among the 47 aSAH areas, 16 （34.04%） were located at the convexity and interhemisphere,19（40.43%） belonged to cisterns,6 （12.77%） were tentorial subarachnoid hemorrhage （SAH）,and 6（12.77%） were intraventricular hemorrhage. The aSAH was characterized by hypointense signal areas surrounded by cerebrospi- nal fluid on SWI and formed a ＂triangle＂ sign in the sulci or cisterns. Compared with the smooth- looking veins,SAH tended to have a rough boundary and inhomogeneous signal intensity. The in- traventricular hemorrhage had a ＂fluid-fluid level＂ shape. Conclusion The aSAH can be recog- nized by SWI through its signal intensity and unique morphology. SWI can provide complementa- ry information on aSAH from CT and MRI.