title: Diagnostic value of dynamic contrast-enhanced MRI for submucosal palatal tumors.
abstract: OBJECTIVE
  To evaluate the diagnostic value of dynamic contrast-enhanced MRI (DCE-MRI) for differentiating between benign and malignant tumors in the palate.
  
  
  METHODS
  26 patients with submucosal palatal tumors were preoperatively examined using DCE-MRI. Their maximum contrast index (CImax), time of CImax (Tmax), and washout ratios (WR300 and WR600) were determined from contrast index curves. The submucosal palatal tumors were divided into two groups according to their Tmax values: the early enhancement group (Tmax<300 s) consisted of 9 malignant tumors and 6 benign tumors, while the late enhancement group (Tmax≥300 s) included one malignant tumor and 10 benign tumors. We compared the following DCE-MRI parameters between the benign and malignant tumors: CImax and Tmax in all cases and CImax, Tmax, and the washout ratios in the early enhancement group. In addition, we performed a regression analysis of the relationships between tumor size and DCE-MRI parameters; i.e., CImax, Tmax, and washout ratios, among the malignant salivary gland tumors and pleomorphic adenomas.
  
  
  RESULTS
  In all cases and the early enhancement group, significant differences in Tmax were detected between the benign and malignant tumors (P<0.001 and P<0.05, respectively), and the optimal Tmax cutoff value for differentiating between them was found to be 165 s. None of the other parameters displayed significant differences between the benign and malignant tumors. Only the WR600 of the pleomorphic adenomas was significantly correlated with tumor size (R2=0.92, P<0.001).
  
  
  CONCLUSIONS
  Tmax is a useful parameter for distinguishing between benign and malignant submucosal palatal tumors.
authors.affiliation: Department of Oral Diagnosis and Dentomaxillofacial Radiology, Okayama University Hospital, and Department of Oral and Maxxilofacial Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 5-1 Shikata-cho, 2-chome, Kita-ku, Okayama 700-8525, Japan. hidenobu@md.okayama-u.ac.jp
authors.forename: Hidenobu
authors.initials: H
authors.lastname: Matsuzaki
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Yanagi
authors.forename: Marina
authors.initials: M
authors.lastname: Hara
authors.forename: Naoki
authors.initials: N
authors.lastname: Katase
authors.forename: Miki
authors.initials: M
authors.lastname: Hisatomi
authors.forename: Teruhisa
authors.initials: T
authors.lastname: Unetsubo
authors.forename: Hironobu
authors.initials: H
authors.lastname: Konouchi
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Takenobu
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Nagatsuka
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Asaumi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000473:pathology*; D010157:Palatal Neoplasms / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA