title: Dynamic contrast-enhanced magnetic resonance imaging in radiotherapeutic efficacy in the head and neck tumors.
abstract: OBJECTIVE
  The purpose to this study is to identify correlations between pathology and dynamic contrast-enhanced magnetic resonance imaging (MRI) and to assess the utility of this technique in the evaluation of radiation response for head and neck cancer.
  
  
  METHODS
  MRI was prospectively performed after radiotherapy in 27 patients with various head and neck tumors. After bolus injection of contrast material, a dynamic study was performed using a spoiled gradient-recalled imaging sequence. The maximum slope of increase (MSI) on the time-intensity curve was displayed as a color-coded image. The ratio of MSI (MSIR) was obtained for tumor and normal muscles. Pathological specimens were obtained after MRI in all cases. Histological grading of irradiation changes was classified into 5 grades (0-4). Correlations between MSIR and histological grade were examined.
  
  
  RESULTS
  Histologically, 18 tumors were classified as grade 2 (presence of viable tumor cells), 4 were grade 3 (nonviable tumor cells), and 5 were grade 4 (no tumor cells). Although the mean +/- SD of MSIR in patients with histological grade 2 or 3 was 7.4 +/- 7.9, MSIR in patients with grade 4 was 1.8 +/- 0.73, representing a significant difference ( P < .05). Every patient with grade 4 displayed an MSIR of 2.5 or less, although 5 of 22 patients with grade 2 or 3 had an MSIR of 2.5 or less.
  
  
  CONCLUSIONS
  MSI quantitatively reflects response to radiotherapy for head and neck cancer. Color-coded MSI display is feasible for depicting permeability changes after radiotherapy.
authors.affiliation: Department of Radiology, Akita University School of Medicine, Akita City, Japan. tomura@med.akita-u.ac.jp
authors.forename: Noriaki
authors.initials: N
authors.lastname: Tomura
authors.forename: Koichi
authors.initials: K
authors.lastname: Omachi
authors.forename: Ikuo
authors.initials: I
authors.lastname: Sakuma
authors.forename: Satoshi
authors.initials: S
authors.lastname: Takahashi
authors.forename: Junichi
authors.initials: J
authors.lastname: Izumi
authors.forename: Osamu
authors.initials: O
authors.lastname: Watanabe
authors.forename: Jiro
authors.initials: J
authors.lastname: Watarai
authors.forename: Masato
authors.initials: M
authors.lastname: Sageshima
mesh_terms: D000368:Aged; D005260:Female; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D007012:Hypopharyngeal Neoplasms / Q000532:radiotherapy; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009959:Oropharyngeal Neoplasms / Q000532:radiotherapy; D011446:Prospective Studies; D014062:Tongue Neoplasms / Q000532:radiotherapy