Ikeda Y, Nakazawa S, Yamakawa K, Kobayashi S, Tsuji Y, Nishimura N
No Shinkei Geka. 1981;9(3):401-6.
Epidural hematoma in the posterior fossa is a rare clinical entity which requires the early diagnosis and treatment, and the difficulty of the diagnosis has been pointed out. However, more recently CT scan began to use to make the valuable diagnostic method for traumatic posterior fossa hematomas. Epidural hematoma may be classified as acute, subacute and chronic, according to the time of free interval or lucid interval after injury. In this paper three acute cases and two subacute cases are reported. CT findings in acute cases show two different types. "Type I" shows crescent or lenticular high density area which is not enhanced after contrast infusion. "Type II" shows lenticular low density area with membranous high density region in its medial side after contrast infusion. In subacute cases plain CT scan shows lenticular iso or low density area with membranous high density region in its medial side. Forty five cases of posterior fossa epidural hematoma in the review of the literature of this country are discussed. Disturbances of the consciousness are the most predominant symptoms in acute cases, while in subacute cases cerebellar signs, vomiting, headache and choked disc are noted. Angiographical examinations may not always be valuable in collecting the direct information of the existence of the epidural hematoma. Liquor cavity in the posterior fossa which is thought to serve as a buffer action of hematoma is about 20 ml, so we discuss about the volume of hematoma, especially of 20 ml, associated with clinical course and prognosis. Volume of epidural hematoma is one of the most important factors affecting clinical course and prognosis. In summary of these our experiences, we again emphasize the value of CT scan as the rapid, noninvasive, accurate radiological examination in the diagnosis of traumatic posterior fossa epidural hematoma.
后颅窝硬膜外血肿是一种罕见的临床病症，需要早期诊断和治疗，其诊断难度已被指出。然而，最近CT扫描开始被用作诊断外伤性后颅窝血肿的重要方法。硬膜外血肿可根据受伤后自由间隔或清醒间隔的时间分为急性、亚急性和慢性。本文报告了3例急性病例和2例亚急性病例。急性病例的CT表现有两种不同类型。“I型”表现为新月形或透镜状高密度区，增强扫描后无强化。“II型”表现为透镜状低密度区，增强扫描后内侧有膜状高密度区。亚急性病例平扫CT表现为透镜状等密度或低密度区，内侧有膜状高密度区。本文讨论了国内文献复习中45例后颅窝硬膜外血肿的情况。意识障碍是急性病例中最主要的症状，而亚急性病例则有小脑体征、呕吐、头痛和视乳头水肿。血管造影检查在获取硬膜外血肿存在的直接信息方面不一定总是有价值的。后颅窝的液腔被认为对血肿有缓冲作用，约为20毫升，因此我们讨论了血肿的体积，特别是20毫升的血肿与临床病程和预后的关系。硬膜外血肿的体积是影响临床病程和预后的最重要因素之一。总结我们的这些经验，我们再次强调CT扫描作为一种快速、无创、准确的影像学检查在诊断外伤性后颅窝硬膜外血肿中的价值。
