Cortical Surface Area Rather Than Cortical Thickness Potentially Differentiates Radiation Encephalopathy at Early Stage in Patients With Nasopharyngeal Carcinoma

Abstract

Radiation encephalopathy (RE) is one of the most severe complications in nasopharyngeal carcinoma (NPC) patients after radiotherapy (RT). However, the morphological alteration of early RE is insufficiently investigated. We aimed to investigate the cortical thickness and surface area alterations in NPC patients with or without RE in the follow-up. A total of 168 NPC patients each underwent a single scan and analysis at various times either Pre-RT (n = 56) or Post-RT (n = 112). We further divided the Post-RT NPC patients into three groups based on the time of the analysis following RT (Post-RTwithin 6 months and Post-RT7-12 months) or whether RE signs were detected in the analysis (Post-RTRE proved in follow-up). We confined the vertex-wise analyses of the cortical thickness and surface area to the bilateral temporal lobes. Interestingly, we revealed a gradual increase in the cortical surface area of the temporal lobe with increasing time after RT within the Post-RTRE proved in follow-up group, consistent with the between-group findings, which showed a significant increase in cortical surface area in the Post-RTRE proved in follow-up group relative to the Pre-RT group and the Post-RTwithin 6 months group. By contrast, such a trend was not observed in the cortical thickness findings. We concluded that the cortical surface area, rather than cortical thickness, may serve as a potential biomarker for 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

“…In comparison with the pre-RT group, we found significantly decreased LGI in the bilateral STG/MTG in NPC patients treated with CCRT. These findings are in line with previous structural studies, which reported significant alterations in GM volume, cortical surface area, and cortical thickness in NPC patients following their treatment (6, 11, 13, 14). Some DTI studies also provided evidence of WM damage in NPC patients following treatment (7, 15, 30), as reflected by altered fractional anisotropy (FA) and/or mean diffusivity (MD) in the temporal lobes.…”

“…The inclusion criteria for all patients in this study were as follows: (1) Pathologically confirmed NPC patients; (2) normal-appearing brain parenchyma on MRI; (3) right-handedness; (4) more than 6 years of education; and (5) an age range from 20 to 60 years. Exclusion criteria included patients with brain parenchymal invasion, brain tumors, prior substantial head trauma or surgery, neurological or psychiatric diseases, alcoholism or drug abuse, or any other major intracranial disease (6). The diagnostic criteria for RE included the following three aspects: a history of NPC with RT, typical MRI findings in the temporal lobes, and exclusion of other intracranial disease (Figure S1).…”

“…Radiation encephalopathy (RE) is one of the most severe complications in patients with NPC who have undergone RT, and has been a subject of attention for several decades. Clinically, RE has a high incidence rate of 7–11%, and is commonly associated with severe cognitive difficulties, psychological problems, and oppressive symptoms (5, 6), which can all seriously affect patients' survival and quality of life. Given the irreversibility of RE at the time of clinical diagnosis, the early detection of treatment-related structural and functional brain alterations prior to RE is of great importance for its early identification and timely prevention.…”

“…For example, some functional MRI (fMRI) studies have reported that post-RT NPC patients showed altered local brain activities and intra- and/or inter-network functional connectivity (FC) in the cerebellum and cerebrum in comparison with pre-RT patients (7–10). Using voxel-based morphometry (VBM) and surface-based morphometry (SBM), several structural MRI (sMRI) studies have shown decreased gray matter (GM) volume, cortical thinning, and increased cortical surface area in specific brain regions, including the bilateral temporal lobes (6, 11–14). Using tract-based spatial statistics (TBSS), a diffusion tensor imaging (DTI) study reported impaired white matter (WM) microstructural integrity in early phase post-RT patients (15).…”

Sensorimotor and pain‐related alterations of the gray matter and white matter in Type 2 diabetic patients with peripheral neuropathy

“…In the present study, two genetically and phenotypically independent morphological indices, namely cortical thickness and cortical surface area, were adopted to assess the alterations in cortical structure (Hogstrom, Westlye, Walhovd, & Fjell, ; Panizzon et al, ; Rakic, ; Rimol et al, ; Zhang et al, ; Zhang et al, ). Because each index measures a unique aspect of cortical morphology, analyzing them separately might help uncover the neural mechanisms involved in the development of DPN.…”