目的 应用基于体素的形态学 (VBM)方法，比较鼻咽癌放疗前与放疗后 早期脑灰质容积的变化，并分析放疗后 脑灰质异常和患者整体认知评分的相关 性。方法 将24例通过病理确诊的首次 接受放疗的鼻咽癌患者纳入本研究，每 位患者在放疗前(放疗前组)及完成放疗 后6个月以内(放疗后组)分别接受高分 辨三维T1加权像的采集。运用基于SPM8 的VBM8工具包进行数据后处理。同期采 用MoCA量表测评所有患者的整体认知水 平。结果 鼻咽癌放疗后组的灰质体积在 左侧小脑、右侧额内侧回及左侧额叶(左 侧中央前回)较放疗前组缩小(P＜0.05， FDR校正，簇体积＞50个体素)。放疗后 组右侧额内侧回的平均灰质体积和患者 MoCA总评分呈正相关（r＝0.431，P＝ 0.036）。结论 VBM方法可以灵敏地探 测到鼻咽癌放疗后脑灰质体积的异常改 变，这可能为放疗后认知功能损害的潜 在的发病机制提供新的认识。

Objective To assess radiation-induced changes of brain gray matter volume (GMV) in nasopharyngeal carcinoma (NPC) patients before and after radiation therapy (RT) using voxel-based morphometry (VBM) and investigate possible correlation with overall cognitive scores. Methods A total of twenty four patients with pathologically diagnosed as NPC and treated with the first RT were recruited for the study. High resolution three-dimensional T1 weighted image acquisition was conducted respectively in each patient before radiotherapy (pre-RT) and within 6 months after completion of radiotherapy (post-RT). Data were processed using the SPM8 based VBM8 toolbox. Over the same period, the Montreal Cognitive Assessment (MoCA) scale was used to assess the overall cognitive function of all patients. Results We detected significantly decreased GMV in the left cerebellum, right medial frontal gyrus and left precentral gyrus within 6 months after RT compared to pre-RT (P＜0.05, FDR corrected, cluster size＞ 50 voxels). Moreover, GMV loss in the right medial frontal gyrus was positively correlated with MoCA scores. Conclusion VBM approach may sensitively detect the abnormal GMV in the NPC patients after RT, which might provide new insight into the pathogenesis of radiation-induced cognitive impairment.