Department of Medical Imaging, Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center for Cancer Medicine; Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou, People's Republic of China.
Department of Oncology, The First Affiliated Hospital of Ganzhou Medical University, Ganzhou, Jiangxi, People's Republic of China.
Brain Imaging Behav. 2019 Aug;13(4):1160-1171. doi: 10.1007/s11682-018-9931-z.
Increasing evidence indicates that radiation-induced injury to the hippocampus may play a critical role in neurocognitive dysfunction in patients with nasopharyngeal carcinoma (NPC). However, few studies have assessed RT-induced hippocampal structural alterations in these patients early after radiotherapy (RT). In this study, 58 NPC patients were longitudinally followed up prior to treatment initiation as well as 3 and 6 months after RT, respectively. Twenty comparable normal controls were recruited and followed up in parallel. A novel magnetic resonance imaging (MRI)-based automated method was used to label hippocampal subfields. The linear mixed model was employed to evaluate longitudinal changes in the volumes of the whole hippocampus and seven hippocampal subfields. Time-dependent volume reduction was observed in the bilateral hippocampus, as well as in the bilateral granule cell layer (GCL), bilateral cornu ammonis 1 (CA1), bilateral molecular layer (ML), and bilateral subiculum (SUB) in NPC patients, but not in controls. Moreover, volume deficits in the bilateral hippocampus, bilateral GCL, and right ML showed dose-dependent patterns, and high volume losses in the bilateral hippocampus, bilateral GCL, left SUB, and right ML were associated with a rapid decline in cognitive function. Our findings demonstrated that the hippocampal subfields were selectively injured by irradiation-related early neurotoxic effects, which might account for cognitive impairment in NPC patients at an early stage after RT. Further, structural MRI could serve as a potential noninvasive imaging biomarker for the early detection of radiation effects on the hippocampus in NPC patients after RT.
越来越多的证据表明，辐射诱导的海马损伤可能在鼻咽癌（NPC）患者的神经认知功能障碍中起关键作用。然而，很少有研究评估这些患者在放射治疗（RT）后早期 RT 诱导的海马结构改变。在这项研究中，58 例 NPC 患者在治疗前、RT 后 3 个月和 6 个月分别进行了纵向随访。同时招募了 20 例可比的正常对照者进行平行随访。采用一种新的基于磁共振成像（MRI）的自动方法对海马亚区进行标记。采用线性混合模型评估全海马和 7 个海马亚区体积的纵向变化。在 NPC 患者中，双侧海马以及双侧颗粒细胞层（GCL）、双侧角回 1（CA1）、双侧分子层（ML）和双侧下托（SUB）均观察到随时间的体积减少，但在对照组中未观察到。此外，双侧海马、双侧 GCL 和右侧 ML 的体积缺损呈剂量依赖性模式，双侧海马、双侧 GCL、左侧 SUB 和右侧 ML 的高体积损失与认知功能的快速下降有关。我们的研究结果表明，海马亚区被辐射相关的早期神经毒性作用选择性损伤，这可能解释了 NPC 患者在 RT 后早期认知障碍的原因。此外，结构 MRI 可以作为 NPC 患者 RT 后早期检测海马辐射效应的潜在无创成像生物标志物。
