Table_1_Structural network alterations in patients with nasopharyngeal carcinoma after radiotherapy: A 1-year longitudinal study.PDF

This longitudinal study explored the changed patterns of structural brain network after radiotherapy (RT) in patients with nasopharyngeal carcinoma (NPC). Diffusion tensor imaging (DTI) data were gathered from 35 patients with NPC at four time points: before RT (baseline), 0∼3 (acute), 6 (early delayed), and 12 months (late-delayed) after RT. The graph theory was used to characterize the dynamic topological properties after RT and the significant changes were detected over time at the global, regional and modular levels. Significantly altered regional metrics (nodal efficiency and degree centrality) were distributed in the prefrontal, temporal, parietal, frontal, and subcortical regions. The module, that exhibited a significantly altered within-module connectivity, had a high overlap with the default mode network (DMN). In addition, the global, regional and modular metrics showed a tendency of progressive decrease at the acute and early delayed stages, and a partial/full recovery at the late-delayed stage. This changed pattern illustrated that the radiation-induced brain damage began at the acute reaction stage and were aggravated at the early-delayed stage, and then partially recovered at the late-delayed stage. Furthermore, the spearman’s correlations between the abnormal nodal metrics and temporal dose were calculated and high correlations were found at the temporal (MTG.R and HES.L), subcortical (INS.R), prefrontal (ORBinf.L and ACG.L), and parietal (IPL.R) indicating that these regions were more sensitive to dose and should be mainly considered in radiotherapy treatment plan.

本项纵向研究探讨了鼻咽癌（Nasopharyngeal Carcinoma, NPC）患者接受放射治疗（Radiotherapy, RT）后脑结构网络的动态变化模式。研究从35例NPC患者的4个时间点采集弥散张量成像（Diffusion Tensor Imaging, DTI）数据：放疗前（基线期）、放疗后0~3个月（急性反应期）、6个月（早期延迟期）以及12个月（晚期延迟期）。本研究采用图论（Graph Theory）方法表征放疗后脑结构网络的动态拓扑属性，并在全局、区域及模块层面检测到随时间推移的显著变化。存在显著改变的区域指标（节点效率与度中心性）分布于前额叶、颞叶、顶叶、额叶及皮层下脑区。模块内连接出现显著变化的模块，与默认模式网络（Default Mode Network, DMN）具有高度重叠性。此外，全局、区域及模块层面的指标在急性反应期与早期延迟期呈现进行性下降趋势，并在晚期延迟期出现部分/完全恢复。该变化模式表明，放射诱导的脑损伤始于急性反应期，于早期延迟期加重，并在晚期延迟期实现部分恢复。进一步计算异常节点指标与时间剂量的斯皮尔曼相关性（Spearman's Correlation）后发现，颞叶区（右侧颞中回MTG.R与左侧赫歇尔回HES.L）、皮层下区（右侧岛叶INS.R）、前额叶区（左侧眶额下回ORBinf.L与左侧前扣带回ACG.L）以及顶叶区（右侧顶下小叶IPL.R）均存在高度相关性，提示上述脑区对放射剂量更为敏感，应在放射治疗计划中予以重点考量。