[摘 要] 目的 探讨蛛网膜下腔出血与大脑纵裂的大脑镰鉴别诊断。 方法 回顾性分析大脑正中部、小脑幕呈线形高密度影的脑出血病人100例。 结果 所有病例均有纵裂或大脑镰高密度影，占100%。小脑幕呈线形高密度影为95例，占95%。蛛网膜下腔出血77例，占77%，其中漏诊22例，均为破入脑室的脑内血肿。误诊为蛛网膜下腔出血1例。脑内血肿65例，占65%。偏密征15例，占15%。外侧裂呈高密度影为22例，占22%。脑沟呈高密度影为32例，占32%。脑池呈高密度影为14例，占14%。脑室呈高密度影为36例，占36%。硬膜下血肿8例，占8%。硬膜外血肿11例，占11%。合并硬膜下积水6例，占6%。脑积水1例，占1%。脑梗塞1例，占1%。外伤原因24例，占24%。 结论 蛛网膜下腔出血急性期CT表现为基底池、外侧裂池、脑沟较为广泛的高密度影。偏密征是诊断外伤性蛛网膜下腔出血少量积血的一个可靠的CT征象。脑内血肿破入脑室，同样也会有蛛网膜下腔出血(积血)。对于有蛛网膜下腔出血的病人，建议一周后复查CT。大脑镰为正中部线形高密度影。

    [关键词] 蛛网膜下腔出血;大脑镰;CT;鉴别诊断

    Differential diagnosis of subarachnoid hemorrhage and falx cerebri by CT

    ZHANG Xin-lian

    Department of CT，Kuitun Hospital of Large Military Unit in Xinjiang，Kuitun833200，China

    Abstract:Objective To investigate the differential diagnosis of subarachnoid hemorrhage and falx cerebri by CT.Methods We retrospec-tively analyzed CT scans of100cases who suffered from cerebral hemorrhage with high-density image in brain centralis and tentorium cerebelli.Re-sults All cases presented high density image in interhemisphere and falx cerebri.Ninety-five presented high density image in tentorium cerebelli.Seventy-seven suffered from subarachnoid hemorrhage.Twenty-two misdiagnosed were intracerebral hematoma owing to bleeding into ventriculus.One was misdiagnosed as subarachnoid hemorrhage.Sixty-five were intracerebral hemorrhage.Fifteen presented hemilateral cistemal hyperdense sign.Twenty-two presented high density image in sylvian cistern.Thirty-two presented high density image in brain sulcus.Fourteen presented high density image in brain cistern.Thirty-six presented high density image in ventriculus.Eight presented subdural hematoma.Eleven presented epidural hema-toma.Six presented subdural fluid accumlation and one cerebral fluid accumlation and one infarction.Twenty-four were caused by injure.Conclu-sion Subarachnoid hemorrhage are usually presented high density image in brain sulcus and cistern by CT scan.Hemilateral cistemal hyperdense sign is a reliable CT sign for the diagnosis of traumatic subarachnoid hemorrhage with small amount of bleeding when intracerebral hemorrhage flows into ventriculus or subarachnoid hemorrhage occurs.The patients with subarachnoid hemorrhage are suggested do CT again one week later.Falx cere-bri is presented high density image in brain centralis. ......