title: [Magnetic resonance perfusion weighted imaging manifestation of late radiation-induced encephalopathy at temporal lobe].
abstract: OBJECTIVE
  The imaging appearances of radiation-induced encephalopathy (REP) of nasopharyngeal carcinoma (NPC) patients were widely reported. As a new technique, magnetic resonance perfusion weighted imaging (MR PWI) is gradually applied to clinical study of REP. This study was designed to observe the characteristics of REP of NPC patients on MR PWI, and investigate its diagnostic value.
  
  
  METHODS
  The MRI and MR PWI records of 26 volunteers and 19 NPC patients with 37 lesions of MRI-diagnosed temporal lobe REP were retrospectively analyzed. The MRI was performed 30 months to 9 years after radiation therapy for NPC. The imaging sequences included T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), MR PWI, and Gd-DTPA-contrasted T1WI.
  
  
  RESULTS
  Unilateral temporal lobe was involved in 1 case of REP, and bilateral temporal lobes in 18 cases of REP. MR PWI revealed that in edema areas of REP, relative cerebral blood volume (rCBV) and relative cerebral blood flood (rCBF) were decreased, mean transit time (MTT), time to peak (TTP), and time of arrival (TO) were delayed simultaneously; in demolished blood-brain barrier areas of REP, rCBV and rCBF were normal, but MTT, TTP, and TO were delayed; no blood perfusion was observed in myelinopathy areas of REP.
  
  
  CONCLUSIONS
  MR PWI can clearly reveal brain blood perfusion changes in various lesions of REP, and indicate that obvious malfunction of brain blood perfusion is occurred in REP.
authors.affiliation: Department of Radiology, The Second Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, P.R. China. fstomz@21cn.com
authors.forename: Ji-Quan
authors.initials: JQ
authors.lastname: Zhao
authors.forename: Bi-Ling
authors.initials: BL
authors.lastname: Liang
authors.forename: Jun
authors.initials: J
authors.lastname: Shen
authors.forename: Xue-Hui
authors.initials: XH
authors.lastname: Zhang
authors.forename: Ying
authors.initials: Y
authors.lastname: Sun
mesh_terms: D000328:Adult; D001810:Blood Volume; D001812:Blood-Brain Barrier; D002560:Cerebrovascular Circulation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000175:diagnosis* / Q000209:etiology; D011878:Radiotherapy / Q000009:adverse effects*; D012189:Retrospective Studies; D013702:Temporal Lobe / Q000098:blood supply / Q000473:pathology / Q000528:radiation effects*