原发性中枢神经系统淋巴瘤的MRI表现

目的 探讨原发性中枢神经系统淋巴瘸（Primaiv Central Nervous System Lymphoms．PCNSL）的MRI表现特征。方法 回顾性分析26例术前行MRI检查并经病理证实的原发性中枢神经系统淋巴瘤资料，主要研究PCNSL的发生部位．信号特征、强化方式、瘤周水肿、室管膜播散以及胼胝体累及情况。结果 26例中7例为单发，19例为多发；其中基底节、脑室旁、胼胝体区16例，半球周边白质区7例，同时伴室管膜下结节13例；仅发生于脑室内者3例。累及胼胝体时，均可见典型“蝶翼征”。常规平扫实性部分表现为T1WI低信号，T2WI等稍高信号。增强实性部分表现为明显均匀强化24例，2例表现为边缘环形中度强化。脑室内病灶或室管膜下播散结节，均未见坏死区，增强呈明显均匀强化。瘤周水肿因部位而异，基底节、脑室旁、胼胝体区病灶水肿多轻度到中度，以轻度为主；半球周边病灶水肿多较明显，呈中度到重度。结论 绝大多数PCNSL表现较具特征性，MRT检查有助于提高正确诊断率。

MRI features of primary central nervous system lymphomas

Objective To evaluate the MRI features of Primary Central Nervous System Lymphoma(PCNSL).Methods MRI findings of 26 cases with pathologicallyproved PCNSL were analyzed retrospectively and the study emphasized on the location, signal feature,contrast-enhanced type,perilesional edema,ependymal seeding,and infiltration of corpus callosum.Results On the 26 cases(7 of them were solitary,the others multiple),16 of them were located in the corpus callosum,basal ganglia and periventricule region,7 cases encephalic surface and white-gray matter junction region,3 cases intraventricule,.13 cases of them associated with ependymal seeding lesions.Typical "butterfly sign"was found in the corpus callosum cases.Plain scan displayed hypointensity on T 1 WI and iso-to hyperintensity on T 2 WI.After the infusion of paramagnetic contrast material,24 of them demonstrated homogeneous enhancement in the solid portion,while there was ring enhancement in 2 cases.Intraventricular and ependymal seeding lesions all showed as homogeneous masses and intensive homogeneous enhancement.Perilesional edema differented with the locations.There was mild to moderate edema in the corpus callosum,basal ganglia and periventricule region lesions, while moderate to high in the encephalic surface and white-gray matter junction region lesions.Conclusion Most PCNSL have typical MRI characteristics,which is helpful for the correct diagnosis of PCNSL preoperatively.