title: Head and neck lesions: characterization with diffusion-weighted echo-planar MR imaging.
abstract: OBJECTIVE
  To evaluate whether apparent diffusion coefficients (ADCs) calculated from diffusion-weighted echo-planar magnetic resonance (MR) images can be used to characterize head and neck lesions.
  
  
  METHODS
  Diffusion-weighted echo-planar MR imaging was performed with a 1.5-T MR unit in 97 head and neck lesions in 97 patients. Images were obtained with a diffusion-weighted factor, factor b, of 0, 500, and 1,000 sec/mm(2), and an ADC map was constructed. The ADCs of lesions, cerebrospinal fluid, and spinal cord were calculated.
  
  
  RESULTS
  Acceptable images for ADC measurement were obtained in 81 (84%) patients. The mean ADC of malignant lymphomas, (0.66 +/- 0.17[SD]) x 10(-3) mm(2)/sec (n = 13), was significantly smaller (P <.001) than that of carcinomas. The mean ADC of carcinomas, (1.13 +/- 0.43) x 10(-3) mm(2)/sec (n = 36), was significantly smaller (P =.002) than that of benign solid tumors. The mean ADC of benign solid tumors, (1.56 +/- 0.51) x 10(-3) mm(2)/sec (n = 22), was significantly smaller (P =.035) than that of benign cystic lesions, (2.05 +/- 0.62) x 10(-3) mm(2)/sec (n = 10). No significant differences were seen in the mean ADC of cerebrospinal fluid and of spinal cord among four groups of lesions. When an ADC smaller than 1.22 x 10(-3) mm(2)/sec was used for predicting malignancy, the highest accuracy of 86%, with 84% sensitivity and 91% specificity, was obtained.
  
  
  CONCLUSIONS
  Measurement of ADCs may be used to characterize head and neck lesions.
authors.affiliation: Department of Radiology, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.forename: S
authors.initials: S
authors.lastname: Takashima
authors.forename: F
authors.initials: F
authors.lastname: Takayama
authors.forename: S
authors.initials: S
authors.lastname: Kawakami
authors.forename: A
authors.initials: A
authors.lastname: Saito
authors.forename: T
authors.initials: T
authors.lastname: Matsushita
authors.forename: M
authors.initials: M
authors.lastname: Momose
authors.forename: T
authors.initials: T
authors.lastname: Ishiyama
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000175:diagnosis; D002648:Child; D002675:Child, Preschool; D017352:Echo-Planar Imaging / Q000379:methods*; D005260:Female; D006258:Head and Neck Neoplasms / Q000175:diagnosis*; D006801:Humans; D008223:Lymphoma / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity