Assessment of Early Rapid Hippocampal Atrophy and Microstructural Hippocampal Injury in Nasopharyngeal Carcinoma Patients After Radiotherapy

Motivation: Radiotherapy (RT) for nasopharyngeal carcinoma (NPC) often leads to hippocampal atrophy, impacting cognitive function. Goal(s): To investigate the temporal progression of hippocampal atrophy and microstructural injury in NPC patients (NPCs) post-RT, and identify key clinical and dosimetric factors. Approach: A longitudinal study involving 193 NPCs and 20 healthy controls, utilizing structural and multi-shell diffusion MRI, along with advanced statistical analyses to assess hippocampal changes and risk factors of hippocampal atrophy. Results: Rapid hippocampal atrophy and microstructural injuries were observed in the acute phase post-RT. The maximum dose (Dmax) was identified as the strongest predictor of atrophy, with chemotherapy influencing tolerance doses. Impact: This study emphasizes the need for incorporating hippocampal protection into RT planning for NPCs, given the vulnerability of the hippocampus, the risk of cognitive dysfunction, and the radiation sensitivity of chemotherapy.