少见部位血管瘤型脑膜瘤的MRI表现及误诊分析

Intracranial angiomatous meningioma at uncommon sites:MRI findings and potential pitfalls

目的:分析少见部位血管瘤型脑膜瘤的MRI征象,提高对该病的诊断及鉴别诊断水平。方法:回顾性分析9例(共11个病灶)经手术和病理证实的非大脑凸面的少见部位血管瘤型脑膜瘤的MRI表现。结果:9例位于非大脑凸面的血管瘤型脑膜瘤,分别位于颞叶深部近海马处、蝶窦内及岩尖、枕骨大孔处、窦汇各1例,位于桥小脑角、小脑幕各2例,同时位于鞍上及鞍内者1例;肿瘤体积1.5cm×1.5cm×2.5cm～6cm×6cm×7cm;圆形或类圆形8个,分叶状2个,葫芦形1个;病灶T1WI呈低信号5个,呈等信号4个,呈略高信号2个;T2WI呈高信号7个,呈等信号4个;病灶强化明显且均匀7个,不均匀强化4个。结论:血管瘤型脑膜瘤具有较其他类型脑膜瘤更富血供的影像学特征。MRI可为血管瘤型脑膜瘤的鉴别诊断提供有价值的信息。

Objective： To analyze MRI characteristics of intracranial angiomatous meningioma at uncommon sites （IAMAUS） and further improve the diagnostic accuracy of IAMAUS. Methods：A retrospective analysis of MRI examina- tions was performed in 9 patients （11 lesions） with IAMAUS （non-convex site of cerebrun）. All the 11 lesions were proved by pathology. Results： In the 9 cases with IAMAUS,tumors were located in gyrus hippocampi （n= 1）,temporal lobe （n= 1 ）, sphenoid sinus （n = 1 ）, foramen magoum （n = 1 ）, cerebellopontine angle （ n： 1 ）, confluens sinuum （ n = 1 ）, suprasellar region （n= 1） and tentorium cerebelli （n= 2）, respectively. The tumor volume ranged from 1.5cm ）〈 1. 5cm X 2. 5cm to 6cm X 6cm X 7cm. IAMAUS were round or oval （n= 8）, lobulated （n = 2） and gourd-shaped （ n = 1 ）. On T1WI, IAMAUSs exhibited mild hypo-intensity （n= 5）, iso-intensity （n= 4） and hyper-intensity （n： 2）. On T2 WI, IAMAUS exhibited mild hyper-intensity （n=7）, iso-intensity （n= 4）. On contrast enhanced MRI, IAMAUSs exhibited marked homogeneous en- hancement （n= 7）, marked heterogeneous enhancement （n~ 3）, and no contrast enhancement （n= 1）, respectively. Conclu- sion： MRI can provide valuable diagnostic information for differentiating histopathological subtypes of meningiomas in terms of associated factors such as IAMAUS is more hypervascular than other subtypes of meningiomas on MRI.