鞍上生殖细胞瘤的MRI表现特征的分析

目的 分析鞍上生殖细胞瘤的MRI的表现特征并对其进行鉴别诊断。方法 对11例鞍上生殖细胞瘤的MRI材料进行回顾性分析，研究鞍上生殖细胞瘤的形态、发生部位、T1加权和T2加权成像的信号和增强后的特征。结果 11例鞍上生殖细胞瘤中，4例(36．4％)肿瘤形态不规则，肿瘤侵犯至垂体和垂体柄分界不清。5例(45．5％)肿瘤仅累及垂体柄，引起垂体柄增粗；2例(18．2％)肿瘤累及垂体柄和下丘脑。全部肿瘤外缘清楚。于T1WI呈等信号，T2WI呈稍高信号。增强后侵犯垂体和垂体柄者强化欠均匀，位于垂体柄和累及垂体柄及下丘脑者呈明显均匀强化。结论 鞍上生殖细胞瘤常累及垂体柄及下丘脑或垂体，肿瘤边界清楚，增强后有明显强化。

Analysis of MRI Features of Germinomas in the Suprasellar Region

Objective To analyze the MRI characteristics and differential diagnosis of germinomas in the suprasellar region. Methods Eleven patients with germinomas in the suprasellar region were studied retrospectively. The morphology, location, signal of tumors, and enhancement after administration of contrast medium were analyzed. Results Of eleven patients, the lesions involving the pituitary gland and pituitary stalk were seen in 4 cases, pituitary stalk in 5 cases, and both pituitary stalk and hypothalamic in 2 cases. The margins of tumors were all well-defined. All tumors were iso-intensity on T1-weighted images and mild hyperintensity on T2-weighted images. Heterogeneous enhancement was seen the lesions involving the pituitary gland and puitary handle in four patients, and the remaining lesions showed striking homogeneous enhancement after injection of contrast material. Conclusion Suprasellar germinomas often involve the pituitary stalk and pituitary gland or hypothalamus. After injection of contrast material, the tumors showed marked enhancement.