幕下占位性病变的CT和MRI诊断

目的探讨幕下占位性病变的CT和MRI表现及特征，提高对幕下占位性病变的定性诊断水平。方法分析我院74例经临床和／或手术、病理证实的幕下占位性病变的CT和MRI表现。结果74例中星形细胞瘤和脑膜瘤各12例：听神经瘤和转移瘤各10例：髓母细胞脑瘤8例：血管母细胞脑瘤7例：室管膜瘤、结核瘤和蛛网膜囊肿各3例：动脉瘤2例：三又神经瘤、胆脂瘤、脉络丛乳头状瘤及动静脉畸形各l例。幕下占位性病变中脑内病变44例，脑外病变30例。星形细胞瘤、脑膜瘤、听神经瘤、转移瘤、髓母细胞瘤及血管母细胞瘤为幕下常见的占位性病变，该区占位性病变大部分有特征性的CT和MRI表现，本组CT定位、定性准确率为78％、69％：MRI为95％、89％。结论CT和MRI对该区占位性病变的诊断和鉴别诊断有重要价值。

CT and MRI in the Diagnosis of Infratentorial Space-occupying Lesions

Objective To analyze the appearance and feature of CT and MRI in infratentorial space-occupying lesions, and to raise the qualitative diagnosis level for them. Methods Appearances of CT and MRI were analyzed in seventy-four cases of infratentorial space-occupying lesions confirmed by clinic and/or operation, and pathology in our hospital. Results Out of 74 cases, 12 were astryocytomas, 12 meningiomas, 10 acoustic neuromas, 8 medulloblastomas, 10 metastases, 7 hemangioblastomas, 3 ependymomas, 3 arachnoid cysts, 3 intracrania, l tuberculomals, and the remaining 4 were papilloma of chorial plexus, trigeminalneuromas, epidermoid syst, and intracranial arteriovenous malformations, respectively. And of 74 infratentorial space-occupying lesions, 44 were intracellular tumors and another 30 extracellular tumors. Astryocytoma, meningioma, acoustic neuroma, metastase, medulloblastoma, and hemangioblastoma were most seen frequently in infratentorial space-occupying lesions, and the characteristic CT and MRI findings were noted in most space-occupying lesions in this area. CT accuracy in the site-specific and qualitative diagnosis were 78% and 69% respectively, and MRI accuracy were 95% and 89%. Conclusion CT and MRI can be of important value in the diagnosis and differential diagnosis of space-occupying lesions in this area.