蛛网膜下腔出血主要是由动脉瘤以及脑(脊髓)血管畸形引起,但有15%左右的患者行血管造影检查为阴性结果[1],而其中21%~68%的患者出血局限于中脑前方脑室内,而其临床特点、影像学表现以及预后都同其他非动脉瘤性SAH有着本质的不同[2]。1985年由van Gijn等[3]将其归类为非动脉瘤中 Subarachnoid hemorrhage is mainly caused by aneurysms and vascular malformations of the brain (spinal cord), but about 15% of patients underwent angiography as a negative result [1], and 21% to 68% of them were limited to bleeding Anterior cerebral ventricle, and its clinical features, imaging findings and prognosis with other non-aneurysmal SAH is essentially different [2]. 1985 by van Gijn et al [3] classified as non-aneurysms