title: Radiation-induced changes in normal-appearing gray matter in patients with nasopharyngeal carcinoma: a magnetic resonance imaging voxel-based morphometry study.
abstract: BACKGROUND
  Evidence is accumulating that temporal lobe radiation necrosis in patients with nasopharyngeal carcinoma (NPC) after radiotherapy (RT) could involve gray matter (GM). The purpose of the study was to assess the radiation-induced GM volume differences between NPC patients who had and had not received RT and the effect of time after RT on GM volume differences in those patients who had received RT.
  
  
  METHODS
  We used magnetic resonance imaging voxel-based morphometry (VBM) to assess differences in GM volume between 30 NPC patients with normal-appearing whole-brain GM after RT and 15 control patients with newly diagnosed but not yet medically treated NPC. Correlation analyses were used to investigate the relationship between GM volume changes and time after RT.
  
  
  RESULTS
  Patients who had received RT had GM volume decreases in the bilateral superior temporal gyrus, left middle temporal gyrus, right fusiform gyrus, right precentral gyrus, and right inferior parietal lobule (p < 0.001, uncorrected, cluster size >100 voxels). Moreover, the correlation analysis indicated that regional GM volume loss in the left superior temporal gyrus, left middle temporal gyrus, and right fusiform gyrus were negatively related to the mean dose to the ipsilateral temporal lobe, respectively.
  
  
  CONCLUSIONS
  These results indicate that GM volume deficits in bilateral temporal lobes in patients who had received RT might be radiation-induced. Our findings might provide new insight into the pathogenesis of radiation-induced structural damage in normal-appearing brain tissue. Yet this is an exploratory study, whose findings should therefore be taken with caution.
authors.affiliation: Department of Medical Imaging and Interventional Radiology, Sun Yat-sen University Cancer Center; State Key Laboratory of Oncology in South China; Collaborative Innovation Center for Cancer Medicine, 651 Dongfeng East Road, Guangzhou, 510060, People's Republic of China.
authors.forename: Xiao-Fei
authors.initials: XF
authors.lastname: Lv
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Zheng
authors.forename: Wei-Dong
authors.initials: WD
authors.lastname: Zhang
authors.forename: Li-Zhi
authors.initials: LZ
authors.lastname: Liu
authors.forename: You-Ming
authors.initials: YM
authors.lastname: Zhang
authors.forename: Ming-Yuan
authors.initials: MY
authors.lastname: Chen
authors.forename: Li
authors.initials: L
authors.lastname: Li
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma; D004307:Dose-Response Relationship, Radiation; D005260:Female; D066128:Gray Matter / Q000473:pathology / Q000528:radiation effects*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000532:radiotherapy*; D009929:Organ Size; D011446:Prospective Studies; D055815:Young Adult