A Predictive Scoring Model for Short-Term Local Recurrent Nasopharyngeal Carcinoma Based on Magnetic Resonance Imaging

Pre-symptomatic local brain activity and functional connectivity alterations in nasopharyngeal carcinoma patients who developed radiation encephalopathy following radiotherapy

Radiation encephalopathy (RE) is a common complication in patients with nasopharyngeal carcinoma (NPC) who have received radiotherapy (RT), and recent neuroimaging studies have shown brain alterations in Post-RT patients prior to RE. However, whether there are functional alterations between those Post-RT patients who are proved to have RE in follow-up and those who do not develop it remains largely unknown. Here, we used resting state functional MRI to explore regional homogeneity (ReHo) and functional connectivity (FC) alterations in Post-RT patients with (Post-RT _{RE proved}; n = 18) or without (Post-RT _non-RE; n = 22) RE at follow-up, also making comparisons with a Pre-RT group (n = 23). Compared with the Pre-RT group, patients in Post-RT _non-RE and Post-RT _{RE proved} groups showed concurrent increased and decreased ReHo values in different brain regions inside and/or outside the radiation field, with the alterations in ReHo tending to increase if RE occurred. Seed-based FC analysis showed that compared with the Post-RT _non-RE group, patients in the Post-RT _{RE proved} group had different changing patterns of FC between a region of interest (ROI) in the right temporal lobe and distant brain regions (mainly in the sensorimotor system and default mode network). Receiver operating characteristic (ROC) curve analysis showed that the altered ReHo value in the ROI had excellent diagnostic performance for differentiating NPC patients who developed RE in follow-up from those who did not, with an area under the curve (AUC) value of 0.94. These ReHo and FC findings may provide new insights into the early diagnosis of RE.

Chemotherapy Potentially Facilitates the Occurrence of Radiation Encephalopathy in Patients With Nasopharyngeal Carcinoma Following Radiotherapy: A Multiparametric Magnetic Resonance Imaging Study

Radiation encephalopathy (RE) is deemed to be a disease induced only by radiotherapy (RT), with the effects of chemotherapeutic agents on the brains of nasopharyngeal carcinoma (NPC) patients being largely overlooked. In this study, we investigated structural and functional brain alterations in NPC patients following RT with or without chemotherapy. Fifty-six pre-RT, 37 post-RT, and 108 post-CCRT (concomitant chemo-radiotherapy) NPC patients were enrolled in this study. A surface-based local gyrification index (LGI) was obtained from high resolution MRI and was used to evaluate between-group differences in cortical folding. Seed-based functional connectivity (FC) analysis of resting-state fMRI data was also conducted to investigate the functional significance of the cortical folding alterations. Compared with the Pre-RT group, patients in the Post-CCRT group showed LGI reductions in widespread brain regions including the bilateral temporal lobes, insula, frontal lobes, and parietal lobes. Compared with the Post-RT group, patients in the Post-CCRT group showed LGI reductions in the right insula, which extended to the adjacent frontal lobe. Seed-based FC analysis showed that patients in the Post-CCRT group had lower FC between the insula and the left middle frontal gyrus than patients in the Pre-RT group. The follow-up results showed that patients in the Post-CCRT group had a much higher RE incidence rate (20.4%) than patients in the Post-RT group (2.7%; P = 0.01). These findings indicate that chemotherapy potentially facilitated the occurrence of RE in NPC patients who underwent radiotherapy.