title: Role of diffusion-weighted MRI in differentiation of masticator space malignancy from infection.
abstract: OBJECTIVE
  The aim of this study was to assess the role of the apparent diffusion coefficient (ADC) value in differentiation of masticator space malignancy from infection.
  
  
  METHODS
  A retrospective study of 49 patients (31 male and 18 female; age range 5-66 years) with masticator space lesion was conducted. They underwent spin-echo-type echo planar diffusion-weighted MRI of the head and neck with b-values of 0 mm(2) s(-1), 500 mm(2) s(-1) and 1000 mm(2) s(-1). The ADC maps were reconstructed and the ADC value of the masticator space lesion was calculated.
  
  
  RESULTS
  The mean (± standard deviation) ADC value of masticator space malignancy (0.91 ± 0.21 × 10(-3) mm(2) s(-1)) was significantly lower (p = 0.001) than that of masticator space infection (1.59 ± 0.32 × 10(-3) mm(2) s(-1)). When an ADC value of 1.20 × 10(-3) mm(2) s(-1) was used as a threshold value for differentiating masticator space malignancy from infection, the best result was obtained with an accuracy of 88%, sensitivity of 88%, specificity of 87%, negative predictive value of 94%, positive predictive value of 86% and area under the curve of 0.92. There was a significant difference in the ADC value between squamous cell carcinoma and soft tissue sarcoma (p = 0.001), as well as between bacterial and fungal infection of the masticator space (p = 0.001).
  
  
  CONCLUSIONS
  We concluded that ADC value is a non-invasive promising imaging parameter that can be used for differentiation of masticator space malignancy from infection.
authors: Department of Diagnostic Radiology, Mansoura Faculty of Medicine, Mansoura, Egypt. arazek@mans.edu.eg
authors: A A K
authors: AA
authors: Abdel Razek
authors: N
authors: N
authors: Nada
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001424:Bacterial Infections / Q000175:diagnosis; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D017352:Echo-Planar Imaging / Q000379:methods; D004487:Edema / Q000175:diagnosis; D005157:Facial Pain / Q000175:diagnosis; D005260:Female; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000175:diagnosis*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008228:Lymphoma, Non-Hodgkin / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D009181:Mycoses / Q000175:diagnosis; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012509:Sarcoma / Q000175:diagnosis; D012680:Sensitivity and Specificity; D009057:Stomatognathic Diseases / Q000382:microbiology*; D014313:Trismus / Q000175:diagnosis; D055815:Young Adult