title: The accuracy of computed tomographic perfusion in detecting recurrent nasopharyngeal carcinoma after radiation therapy.
abstract: OBJECTIVE
  To assess the diagnostic accuracy of computed tomographic (CT) perfusion technique in discriminating recurrent nasopharyngeal carcinoma (NPC) after radiation therapy.
  
  
  METHODS
  Forty-eight patients with a pathologic finding as reference standards were divided into 2 groups, recurrent and nonrecurrent NPCs. Perfusion parameters blood flow (BF), blood volume (BV), permeability surface (PS), and mean transit time were statistically analyzed. A receiver operating characteristic curve was used to study whether CT perfusion parameters could aid in detecting recurrent NPC.
  
  
  RESULTS
  Blood flow, BV, and PS values between recurrent NPC (n = 27) and nonrecurrent NPC (n = 21) were 526.8 (168.1) versus 312.1 (214.4) mL/100 g per minute, 35.1 (23.6) versus 9.2 (8.0) (ml/100 g), and 53.4 (34.3) versus 17.6 (14.7) mL/100 g per minute, respectively. There was a significant difference between these 2 groups (P < 0.01). Mean transit time values in these 2 groups were 3.5 (2.0) versus 4.3 (2.7) seconds; there was no statistical difference. To optimize sensitivity and specificity, BF, BV, and PS threshold values for differentiating between recurrent and nonrecurrent NPCs were 537.20 mL/100 g per minute, 37.18 (ml/100 g), and 57.34 mL/100 g per minute, respectively. According to threshold values of BF, BV, and PS, sensitivity and specificity for distinguishing recurrent and nonrecurrent NPCs were 92.6% and 76.2%, 96.3% and 81%, and 81.5% and 61.9%, respectively.
  
  
  CONCLUSIONS
  The CT perfusion technique may be helpful to find patients with recurrent NPC after radiation therapy.
authors.affiliation: Department of Radiology, Oncology Hospital, Guangxi Medical University, Nanning, People's Republic of China. jgq2011@126.com
authors.forename: Guanqiao
authors.initials: G
authors.lastname: Jin
authors.forename: Danke
authors.initials: D
authors.lastname: Su
authors.forename: Lidong
authors.initials: L
authors.lastname: Liu
authors.forename: Xuna
authors.initials: X
authors.lastname: Zhu
authors.forename: Dong
authors.initials: D
authors.lastname: Xie
authors.forename: Wei
authors.initials: W
authors.lastname: Zhao
mesh_terms: D000328:Adult; D000368:Aged; D003287:Contrast Media; D005260:Female; D006801:Humans; D007472:Iohexol / Q000031:analogs & derivatives; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D009364:Neoplasm Recurrence, Local / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D012372:ROC Curve; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide