title: Perfusion characteristics of late radiation injury of parotid glands: quantitative evaluation with dynamic contrast-enhanced MRI.
abstract: We aimed to quantitatively investigate the alteration of parotid perfusion after irradiation using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) based on a two-compartment tracer kinetic model. This study enrolled 19 patients (53.2 +/- 14.9 years) treated by head and neck radiotherapy and 19 age-relevant and sex-matched subjects as a control group. Perfusion parameters (K ( el ), k (21) and A) of parotid glands were analyzed based on the Brix model from T1-weighted DCE-MRI. Suitability of the Brix model was evaluated via Monte Carlo simulation for the goodness-of-fit. Analysis of nonlinear goodness-of-fit showed that the Brix model is appropriate in evaluating the parotid perfusion (R(2) = 0.938 +/- 0.050). The irradiated parotid glands showed significantly lower K ( el ) (P < 0.0005) and k (21) (P < 0.05) and consequently significantly higher value of peak enhancement (P < 0.0005) and time-to-peak (P < 0.0005) compared with non-irradiated ones, suggestive of gradual and prolonged accumulation and delayed wash-out of contrast agent due to increased extracellular extravascular space and decreased vascular permeability in the irradiated glands. Linear regression analysis showed dose-dependent perfusion changes of the irradiated parotid glands. We conclude that quantitative DCE-MRI is a potential tool in investigating parotid gland perfusion changes after radiotherapy.
authors.affiliation: Department of Radiology, Tri-Service General Hospital and National Defense Medical Center, Taipei, Taiwan, Republic of China.
authors.forename: Chun-Jung
authors.initials: CJ
authors.lastname: Juan
authors.forename: Cheng-Yu
authors.initials: CY
authors.lastname: Chen
authors.forename: Yee-Min
authors.initials: YM
authors.lastname: Jen
authors.forename: Hua-Shan
authors.initials: HS
authors.lastname: Liu
authors.forename: Yi-Jui
authors.initials: YJ
authors.lastname: Liu
authors.forename: Chun-Jen
authors.initials: CJ
authors.lastname: Hsueh
authors.forename: Chao-Ying
authors.initials: CY
authors.lastname: Wang
authors.forename: Yu-Ching
authors.initials: YC
authors.lastname: Chou
authors.forename: Yao-Te
authors.initials: YT
authors.lastname: Chai
authors.forename: Guo-Shu
authors.initials: GS
authors.lastname: Huang
authors.forename: Hsiao-Wen
authors.initials: HW
authors.lastname: Chung
mesh_terms: D000328:Adult; D000368:Aged; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010306:Parotid Gland / Q000098:blood supply / Q000293:injuries* / Q000473:pathology*; D011832:Radiation Injuries / Q000175:diagnosis* / Q000209:etiology*; D011859:Radiography; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014987:Xerostomia / Q000175:diagnosis* / Q000209:etiology*; D055815:Young Adult
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA