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

Wei-Hua Liao,Jin-Lei Zhang,Xin-Ru Yuan,Jian-Ming Gao,Li Li,Chishing Zee,Yuan-Chao Zhang,Na Zhang,You-Ming Zhang,Xiao-Ping Yi,Bihong T Chen,Ming-Na Chen,Pei-Qiang Cai,Li-Zhi Liu

doi:10.3389/fnins.2018.00599

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.

Highlights

Nasopharyngeal carcinoma is a malignancy that occurs in the nasopharyngeal epithelium
To explore the specific tendency of the cortical thickness or cortical surface area, we further subdivided the Post-RTRE proved in follow-up patients into NPC patients after RT (Post-RT) Radiation encephalopathy (RE) within 6 months, Post-RT RE 7−12 months, and PostRT RE more than 12 months according to the time intervals between RT and MRI examination
In the Post-RTRE proved in follow-up group, the location for RE is the right side of the temporal lobe (n = 5), left side (n = 9), and the bilateral side (n = 11) (Table 1)

Summary

Introduction

Nasopharyngeal carcinoma is a malignancy that occurs in the nasopharyngeal epithelium. It is endemic in southern China and has an incidence rate between 15 and 50 per 100,000 (Wee et al, 2010; Zhang et al, 2015; Chua et al, 2016). RE has a high 5-year incidence rate of approximately 16% (Zhou et al, 2013) and is usually associated with severe psychological and cognitive problems, such as depression, anxiety and dementia, and oppressive symptoms, including bulbar palsy, headache, dizziness and syncope, which could seriously impact the patients’ quality of life (Tang et al, 2012). The early identification and timely prevention of RE have vital clinical significance

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