title: Role of diffusion-weighted echo-planar MR imaging in differentiation of residual or recurrent head and neck tumors and posttreatment changes.
abstract: OBJECTIVE
  The purpose of this work was to evaluate whether diffusion-weighted MR imaging can be used in differentiating residual or recurrent head and neck tumors from postoperative or postradiation changes.
  
  
  METHODS
  This study included 32 patients clinically suspected for recurrent head and neck tumor after surgery (n=3), radiation therapy (n=13), or both (n=16). Diffusion-weighted MR imaging was done by using a single-shot spin-echo echo-planar sequence. The apparent diffusion coefficient (ADC) value of the suspected lesion was calculated and correlated with pathologic results.
  
  
  RESULTS
  Adequate diffusion-weighted MR images and ADC maps were obtained in 30 patients (93.8%). The mean ADC value of residual or recurrent lesions (1.17 +/- 0.33 x 10(-3) mm(2)/s) was less than that of posttherapeutic changes (2.07 +/- 0.25 x 10(-3) mm(2)/s), and the difference was statistically significant (P<.001). When an ADC value of 1.30 x 10(-3) mm(2)/s was used as a threshold value for differentiation, the best results were obtained with an accuracy of 87%, sensitivity of 84%, specificity of 90%, positive predictive value of 94%, and negative predictive value of 76%.
  
  
  CONCLUSIONS
  Diffusion-weighted MR imaging with ADC measurement has promising results for differentiating residual or recurrent head and neck tumors from postoperative or postradiation changes.
authors.affiliation: Department of Diagnostic Radiology, Faculty of Medicine, Mansoura University, Mansoura, Egypt. arazek@mans.eun.eg
authors.forename: A A K
authors.initials: AA
authors.lastname: Abdel Razek
authors.forename: A Y
authors.initials: AY
authors.lastname: Kandeel
authors.forename: N
authors.initials: N
authors.lastname: Soliman
authors.forename: H M
authors.initials: HM
authors.lastname: El-shenshawy
authors.forename: Y
authors.initials: Y
authors.lastname: Kamel
authors.forename: N
authors.initials: N
authors.lastname: Nada
authors.forename: A
authors.initials: A
authors.lastname: Denewar
mesh_terms: D000368:Aged; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D017352:Echo-Planar Imaging / Q000379:methods*; D005260:Female; D006258:Head and Neck Neoplasms / Q000175:diagnosis* / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis* / Q000517:prevention & control*; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017211:Treatment Failure; D016896:Treatment Outcome