颅内血管外皮细胞瘤的MRI／CT影像学表现

目的：探讨颅内血管外皮细胞瘤（hemangiopericytoma，HPC）的影像特征。方法回顾性分析经病理及免疫组织化学证实的16例HPC患者的CT及MRI表现。所有患者均行MR扫描，6例行CT扫描。结果所有病变均为单发病灶，均位于颅内脑外，均为分叶状肿块，15例位于幕上，1例位于幕下。6例CT平扫均呈稍高密度、间杂低密度，均未见钙化，1例邻近颅底骨质呈侵蚀破坏，5例增强扫描均呈明显不均匀强化，并可见明显增粗的血管影，4例可见明显的瘤周水肿带。T1WI以等、低信号、T2WI以低、高混杂信号为主，2例信号均匀、14例信号不均，13例周围有水肿。增强扫描中15例病灶均明显不均匀强化，1例中度强化。2例病灶与硬膜呈宽基底相连，14例为窄基底相连。16例病灶均未出现“脑膜尾征”。DWI中，7例肿瘤呈等低混杂信号为主。MRS中，4例Cho峰明显升高；2例NAA峰及Cr峰降低。结论HPC影像表现具有一定特点，当脑外肿瘤呈分叶状，内部密度不均匀，有囊变坏死，周围骨质无增生硬化，甚至有破坏吸收改变，水肿较严重，肿瘤内未见钙化，侵犯周围脑组织或并发颅外转移时，提示HPC可能性大。

MRI/CT findings of intracranial hemangiopericytoma

Objective To summarize the imaging features of hemangiopericytoma （HPC） .Methods 16 patients with HPC proven histopathologically were collected .6 cases had CT data and all cases had MR data ,The imaging features and pathological results were retrospectively analyzed .Results All cases were single lesions with lobulated shape ,arose out-side the brain .15 cases （15/16） were supratentorial while 1 case was infratentorial .6 cases with plain scan were manifes-ted as high and low isodensity ,and none had calcification .Smooth erosion of the basicranial skull in 1 lesion .5 cases were obvious heterogeneous enhancement ,and marked enlarged vascular image could be seen .There was obvious perilesional e-dema in 4 cases .There were low signal or equisignal on T1WI ,while T2WI showed high and low signal .The signals of the 2 cases were homogenous ,however ,the signals of the other 14 cases were heterogeneous .In 13 cases ,around the lesions were edema belt .15 cases were obvious inhomogeneous enhancement in CT enhancement scanning .1 case was moderate enhancement .2 tumors were broad-based dural attachment .14 tumors were narrow -based dural attachment .There was no ＆quot;dural tail sign＆quot;in all 16 cases .Most of signals in 7 cases were mixed with low and iso-intensity by DWI .The peaks of cho in 4 cases were significantly increased in MRS ,while the Peaks of NAA and Cr in 2 cases were decreased .Conclusion Image performance of HPC embodies certain characteristics .The features make the HPC possibility more likely ,such as lobulated in shape of the tumors ,inhomogeneous in density ,cyst degeneration or necrosis ,having no hyperplasia and scle-rosis of surrounding bone ,having a change of damage absorption ,having no calcifications ,having some edema ,and inva-ding the surrounding brain or having extracranial metastases .