颅外脑膜瘤的CT和MRI表现

CT and MRI Findings of Extracranial Meningioma

目的:评价颅外脑膜瘤的CT和MRI表现特征及诊断价值。方法:回顾性分析6例经手术病理检查证实的颅外脑膜瘤的CT和MRI表现。其中,仅行CT检查者2例;仅行MRI检查者1例;CT及MRI均查者3例。结果:6例颅外脑膜瘤的CT及MRI表现为:①病变位于咽旁间隙者3例,咀嚼肌间隙者1例,眼眶者2例;②平扫CT上病变均表现为软组织密度肿块,其中3/5病变含有沙粒样钙化。平扫MRI上,病变在T_2WI上均表现为不均匀高信号("椒盐"征);③增强CT和MRI上,病变均呈明显强化表现;④位于咽旁间隙的病变推移(2例)或包绕(1例)颈内动脉,咽侧壁呈受压改变;⑤4/6例病变表现为与颅内脑膜瘤相连,相邻颅骨和眶壁表现为骨质增厚(4例)或吸收(1例)。结论:颅外脑膜瘤的CT和MRI表现以软组织肿块内含钙化、"椒盐"征和邻骨受侵为特点。该病变的CT和MRI表现能为相关鉴别诊断提供有价值信息。

Purpose：The aim of the study was to evaluate the CT and MRI characteristics of extracranial meningioma.Methods：A retrospective review was made in 6 patients with extracranial meningiomas：2 cases were examed with mere CT examination,1 with mere MRI examination,and 3 with both.Results： Extracranial meningioma was identified in the facial space in 4 cases（3 cases in the parapharyngeal space,and 1 in the masticator space） and in the orbit in 2 cases.The plain CT images showed that all lesions were mostly round soft tissue masses.Calcification was found in 3 of 5 cases.In the plain MRI, all lesions were revealed with iso - intensity signal on T_1 WI and uneven hyper - intensity signal on T_2 WI （＂pepper and salt＂ sign）.All masses were obviously enhanced on post - contrasted images.The external carotid artery was displaced by extracranial meningioma in parapharyngeal space in 2 cases,and was encompassed in 1 case.Four of 6 extracranial meningiomas were found lesions with cranial involvement. The patterns of bone erosion（5 cases） by the lesions were identified as thickening in 4 cases and absorption in 1 case.Conclusion：CT and MRI findings of the extracranial meningioma are characterized by a soft tissue mass with calcification,＂pepper and salt＂ sign,and involvement of adjacent bones.It is believed that CT and MRI examination may provide valuable information for the differential diagnosis.