title: Usefulness of diffusion-weighted MR imaging for differentiating between Warthin's tumor and oncocytoma of the parotid gland.
abstract: OBJECTIVE
  To assess the efficacy of diffusion-weighted (DW) MR imaging for differentiating between Warthin's tumor and oncocytoma of the parotid gland.
  
  
  METHODS
  Forty-five histopathologically confirmed parotid gland tumors (41 Warthin's tumors and 4 oncocytomas) were examined by MR imaging including DW imaging.18F-fluorodeoxyglucose PET/CT was also performed in 9 Warthin's tumors and 3 oncocytomas. We retrospectively reviewed the images and compared the MR signal intensities, apparent diffusion coefficients (ADCs), and maximum standardized uptake values (SUVmax) of the solid components between the two pathologies.
  
  
  RESULTS
  The signal intensity ratios (SIRs) on both T2-weighted images (0.92 ± 0.18 vs 0.65 ± 0.13, p < 0.01) and DW images (1.24 ± 0.42 vs 0.43 ± 0.16, p < 0.001) were higher in Warthin's tumors than in oncocytomas. ADCs (0.79 ± 0.11 vs 1.06 ± 0.06 × 10-3mm2/s, p < 0.001) were lower in Warthin's tumors than in oncocytomas. No significant differences in the SIRs on T1-weighted images (1.09 ± 0.12 vs. 0.99 ± 0.07, p = 0.051) and SUVmax (8.22 ± 3.86 vs. 8.11 ± 1.33, p = 0.864) were found between Warthin's tumor and oncocytoma.
  
  
  CONCLUSIONS
  DW imaging with ADC measurements is useful for the differentiation of Warthin's tumor from oncocytoma of the parotid gland.
authors.affiliation: Department of Radiology, Gifu University School of Medicine, 1-1 Yanagido, Gifu, 501-1194, Japan. hkato@gifu-u.ac.jp.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kato
authors.affiliation: Department of Radiology, Gifu University School of Medicine, 1-1 Yanagido, Gifu, 501-1194, Japan.
authors.forename: Keita
authors.initials: K
authors.lastname: Fujimoto
authors.affiliation: Department of Radiology, Gifu University School of Medicine, 1-1 Yanagido, Gifu, 501-1194, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Matsuo
authors.affiliation: Department of Otolaryngology, Gifu University School of Medicine, Gifu, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Mizuta
authors.affiliation: Department of Otolaryngology, Gifu University School of Medicine, Gifu, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Aoki
mesh_terms: D000235:Adenolymphoma / Q000000981:diagnostic imaging*; D018249:Adenoma, Oxyphilic / Q000000981:diagnostic imaging*; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010306:Parotid Gland / Q000000981:diagnostic imaging; D010307:Parotid Neoplasms / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012189:Retrospective Studies
keywords: Diffusion-weighted imaging; Oncocytoma; Parotid gland; Warthin’s tumor