约15%～20%的蛛网膜下腔出血(SAH)病人出血原因不明,这类病人的预后较动脉瘤性SAH 病人要好。头部CT 的临床应用对SAH 病人的诊断有很大帮助,发病后3日内进行CT 检查,对SAH 及其颅内并发症非常敏感,还可鉴别SAH 的病因。脑出血、动脉瘤性SAH 病人,血液常在大脑外侧裂、大脑半球间裂及基底池被探测到。Van Gijn 等(1985)发现在28例非动脉瘤性SAH 病人CT 片中有13例病人的出血主要局限于中脑周围池,而在92例动脉瘤性 About 15% to 20% of patients with subarachnoid hemorrhage (SAH) bleeding unknown reasons, such patients prognosis better than aneurysmal SAH patients. The clinical application of head CT is very helpful for the diagnosis of SAH patients. CT examination within 3 days after onset is very sensitive to SAH and its intracranial complications and can also identify the etiology of SAH. Cerebral hemorrhage, aneurysmal SAH patients, blood often in the lateral cerebral fissure, hemispheric fissure and basal cistern was detected. Van Gijn et al. (1985) found that bleeding in 13 of 28 non-aneurysmal SAH patients was mainly confined to the midbrain peripheral pool, whereas in 92 patients with aneurysm