title: [Diagnostic value of MR diffusion tensor imaging on radiation-induced early brain injury of nasopharyngeal carcinoma after radiotherapy].
abstract: OBJECTIVE
  MR diffusion tensor imaging (DTI), a new MRI technique, can observe water molecule diffusion non-invasively at molecular level. This study was to assess diagnostic value of DTI on post-radiotherapy brain injury by quantitatively analyzing diffuse features of water in bilateral temporal lobes alba of those nasopharyngeal carcinoma (NPC) patients with normal conventional MRI performances.
  
  
  METHODS
  DTI was performed in 13 NPC patients with normal conventional MRI performances after radiotherapy, and 21 healthy controls. Isotropic apparent diffusion coefficient (ADCiso) and anisotropic index (AI) were measured in bilateral temporal lobes alba.
  
  
  RESULTS
  ADCiso of patient group was (631.30+/-27.83) x 10(-6) mm2/s, while that of control group was (651.76+/-39.10) x 10(-6) mm2/s (P>0.05). Temporal lobes diffusion AI decreased significantly in patient group, mean fractional anisotropy (FA) was 0.405+/-0.042, mean relative anisotropy (RA) was 0.355+/-0.044, and mean 1 minus volume ratio (1-VR) was 0.192+/-0.042; while those in control group were 0.463+/-0.047, 0.418+/-0.052, and 0.257+/-0.055, respectively (P< 0.01).
  
  
  CONCLUSIONS
  DTI can early detect subtle alba changes in NPC patients after radiotherapy, which conventional MRI failed to sense. AI is more sensitive than ADCiso, may better describe the diffuse features of water molecules, and evaluate the temporal lobes alba changes before and after NPC radiotherapy.
authors.affiliation: Radiology Department, The Second Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510 120, P.R. China. txp122ct@sohu.com
authors.forename: Xiang-Ping
authors.initials: XP
authors.lastname: Tan
authors.forename: Ji-Quan
authors.initials: JQ
authors.lastname: Zhao
authors.forename: Bi-Ling
authors.initials: BL
authors.lastname: Liang
authors.forename: Bang-Kun
authors.initials: BK
authors.lastname: Xie
authors.forename: Jing-Lian
authors.initials: JL
authors.lastname: Zhong
authors.forename: Rui-Xin
authors.initials: RX
authors.lastname: Ye
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001930:Brain Injuries / Q000175:diagnosis* / Q000209:etiology; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000175:diagnosis*; D013702:Temporal Lobe / Q000528:radiation effects*