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 neuroradiologists to decide whether there was aSAH in the anatomical parts of subarachnoid space .Results 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 intraventricular hemorrhage had a "fluid-fluid level" shape .Conclusion The aSAH can be recognized by SWI through its signal intensity and unique morphology .SWI can provide complementary information on aSAH from CT and MRI .%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(susceptibility-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.
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