目的：探讨侧脑室星形细胞瘤的MRI表现特点，着重观察侧脑室星形细胞瘤的发病部位、与侧脑室周围组织结构的关系，以此推测肿瘤的来源，对侧脑室内肿瘤进行鉴别诊断。方法：回顾性分析经手术病理证实的14例侧脑室星形细胞瘤，14例均行MRI平扫与增强。其中男8例，女6例。年龄13~62岁，平均26岁。结果：毛细胞型星形细胞瘤1例（1/14），星形细胞瘤Ⅱ级7例（7/14）、Ⅲ级4例（4/14）、Ⅳ级2例（2/14）。11例肿瘤MRI表现与手术所见相符：2例位于透明隔，3例位于室间孔区，2例与胼胝体分界不清，4例与丘脑组织分界不清。结论：脑室的星形细胞瘤来源于脑室旁结构，常表现有室旁脑实质同时受累或胼胝体增厚。根据侧脑室星形细胞瘤的发病部位、与侧脑室周围组织结构的关系，结合发病年龄，肿瘤的囊变坏死、出血、瘤周水肿、占位效应及造影剂增强后的表现，可提高肿瘤的诊断及分级准确性。

Objective: To investigate the MRI features of lateral ventricular astrocytoma, and their relationship to the circumventricular organs. Methods: The MRI features were retrospectively analyzed in 14 cases of astrocytoma in lateral ventricle proved by operation and pathology. Nonenhanced and contrast enhanced MRI scanning were done in all cases, including 8 males and 6 females. The patient’s age ranged from 13~62 years old with average age of 26 years old. Result: One case (1/14） as pilocytic astrocytoma; 7 cases (7/14) were of WHO grade Ⅱastrocytoma, 4 cases (4/14) were of WHO grade Ⅲ astrocytoma, 2 cases(2/14) were of WHO grade Ⅳ astrocytoma. In 11 cases, MRI appearance agree with the operations: 2 cases arised from the septum pellucidum, 3 cases situated near the foramen of Monro, 2 cases had obscure boundary with the corpus callosum, and 4 cases had obscure boundary with the thalamus. Conclusion: Base on tumor’s location, patient’s age, and their MRI appearance, it is possible to improve the diagnostic accuracy of lateral ventricular astrocytoma.