目的 总结第三脑室淋巴瘤CT及 MRI影像学特征表现，提高对本病的认识 和诊断水平。方法 回顾分析5例经手术 病理证实为第三脑室淋巴瘤CT及MRI影 像资料并复习相关文献，观察病灶的部 位、形态、大小、边缘、瘤周水肿、MRI 平扫、增强以及1 H-MRS特点。结果 第三 脑室淋巴瘤CT平扫多表现等/稍高密度圆 形或类圆形肿块；MRI平扫表现T1WI呈低 /等信号，T2WI呈等/高信号，增强扫描 病变呈明显均匀强化，且可出现“握拳 征”、“尖角征 ”、“脐凹征”或“开 环征”；1 H-MRS表现为NAA峰减低, Cho峰 升高，Lip峰明显升高。病理上肿瘤细胞 均呈弥漫密集分布，肿瘤细胞大小较一 致，胞浆少，核大，出血、坏死及钙化少 见。结论 第三脑室淋巴瘤具有影像学特 征表现，单纯的影像学对其诊断有一定限 度，确诊仍需临床资料、组织形态学及免 疫组织化学检查，病变性质的确定对选择 治疗方案至关重要。

Objective To study the CT and MRI radiological features of lymphoma in the third ventricle and improve the understanding and diagnosis of it. Methods CT and MRI manifestations of 5 patients with lymphoma in the third ventricle which proved by surgery and pathology were analyzed retrospectively. The follow findings of the lesions were evaluated, including location, morphology, size, margin, peritumoral edema, MRI plain scan, enchancement pattern and 1 H-MRS. Results A1l lesions appeared as round or oval isodensitiy or hyperdensity solid masses on CT scan, isointensity or hypointensity on T1WI, iso intensity or hyper intensity on T2WI, The tumors showed homogeneous marked enhancement on contrast-enhanced scan and manifestated "Fist clenching sign", "close angle sigh", " notch sign" and "open-ring sign". NAA peak reduced, Cho peak increased and Lip peak increased significantly on 1 H-MRS.Pathologically,the tumor cells were diffusely distributed and same sized with less cytoplasm and larged nucleus， calcification, hemorrhage or piece of necrosis were rare. Conclusion Lymphoma of the third ventricle has certain imaging features. The diagnosis of Lymphoma of the third ventricle is limited by imaging alone. Clinical data, histomorphology and immunohistochemistry are still needed to confirm the diagnosis..