幕上脑实质内室管膜瘤的MR及CT诊断探讨

MRI and CT diagnosis of supratentorial intra-cerebral ependymoma

目的探讨MR及CT对幕上脑实质内室管膜瘤诊断的价值。方法分析10例经手术病理证实的幕上脑实质室管膜瘤的MR及CT表现。结果10例幕上脑实质内室管膜瘤,表现为大囊为主型2例,肿瘤由位于深部白质区的大囊与位于皮层区的小部分实质构成。实质为主型8例,其中肿瘤实质内出现单发偏心性液化囊变区5例,出现多发小液化区3例。肿瘤实质与脑灰质比较于T1加权像呈等或略低信号,于T2加权像呈略高信号;在CT平扫时与脑灰质密度相似或略高于脑灰质密度;液化囊变区于T1加权像呈略高或等于脑脊液的低信号,于T2加权像呈等于脑脊液高信号,CT平扫呈略高于脑脊液的低密度。合并出血5例,钙化2例。结论幕上脑实质大囊为主型室管膜瘤,或实质为主型室管膜瘤肿瘤内出现单发偏心性液化囊变区,增强扫描实质部分明显强化,CT扫描肿瘤实质与脑灰质比较呈等或略高密度,部分伴小斑点状钙化,MR及CT表现具有一定特征性;当病灶表现为不规则实质性肿块伴多发小液化囊变区,周围水肿明显时,与恶性星型细胞瘤或胶质母细胞瘤极难鉴别。

Objective To evaluate MR and CT diagnosis of clinical features in supratentorial intra- cerebral ependymoma. Methods The MR and CT images in 10 cases of supratentorial intra - cerebral ependymomas confirmed by pathological examinations were investigated retrospectively. Results In the 10 cases of supratentorial inlra-cerebral ependymoma, a large cystic formation located within the white matter, accompanying with a tiny solid tumor parenchyma located within the cortex area were found in 2 cases; 8 cases manifested solid majored nature, in which a single, eccentric liquefied cystic area was reveled in 5 cases, and multiple tiny liquefied cystic areas were found in the other 3 cases. The parenchyma of the tumors presented iso - intense or slight hypo - intense signals comparing with the gray matter on T1- weighted image, and hyper - intense signals on the T2 - weighed image, Compared with the gray matter, tumors had isoor hyper - attenuation on CT scan. The signal of cyst formation was similar to or slightly higher than that of CSF（cerebral spinal fluid） on T~ - weighed imaZges, and were similar to the signal of CSF on T2 -weighed images. While on the CT images the content of the cystic formation had a slightly higher density than that of the CSF. Evident hemorrhage was revealed in 5 cases. Calcification was demonstrated in 2 cases. Conclusions When supratentorial intra- cerebral ependymoma presented a cystic majored nature or a solid majored nature with a single eccentric liquefied cystics area, characteristic CT or MRI findings may be noticed： the tumor parenchyma showed remarkable enhancement after the contrast agent was given; the solid part of the tumour presents an equal or higher density compared to the cerebral gray matter on the CT scan, and tiny calcification patches may be revealed as well. When the lesion presents an irregular solid natured neoplasm accompanying with multiple tiny liquefied cystic areas with apparent marginal edema, it would be really difficult to differentiate the lesion from the malignant astrocytoma or glioma.