title: Glandular function in Sjögren syndrome: assessment with dynamic contrast-enhanced MR imaging and tracer kinetic modeling--initial experience.
abstract: OBJECTIVE
  To prospectively use dynamic contrast material-enhanced magnetic resonance (MR) imaging and a tracer kinetic model to compare parotid gland microvascular characteristics in patients who have Sjögren syndrome (SS) with those in healthy volunteers.
  
  
  METHODS
  The local research ethics committee approved the study, and written informed consent was obtained from all participants. Twenty-one patients (19 women, two men; age range, 31-73 years) with a diagnosis of SS and 11 healthy volunteers (10 women, one man; age range, 41-68 years) underwent three-dimensional T1-weighted dynamic contrast-enhanced MR imaging of the parotid gland at 1.5 T. A voxel-wise tracer kinetic model and a model-free analysis were applied to the dynamic MR data. Parameter medians and standard deviations were computed to summarize gland microvascular characteristics and gland heterogeneity, respectively. Differences were investigated by using multivariate analysis of variance, t, or U tests. Further investigation was performed by using linear discriminant and receiver operating characteristic analyses.
  
  
  RESULTS
  Compared with the healthy volunteers, the patients with SS had highly significant elevations (P << .001) in the model-free parameter initial area under the curve and in tracer kinetic model parameters, including transcapillary contrast agent transfer constant (P < .001) and extracellular extravascular volume (P < .001). Gland heterogeneity was significantly greater (P < .001) in the patients with SS. Parameter medians and standard deviations enabled excellent differentiation (areas under receiver operating characteristic curve, 0.96 and 1.00, respectively) between the patients with SS and the healthy volunteers.
  
  
  CONCLUSIONS
  Dynamic contrast-enhanced MR imaging has the potential to be used in clinical settings to quantify microvascular function in SS and to differentiate between patients with and those without SS.
authors.affiliation: Department of Imaging Science and Biomedical Engineering, University of Manchester, Stopford Bldg, Oxford Rd, Manchester M13 9PT, England. caleb.roberts@manchester.ac.uk
authors.forename: Caleb
authors.initials: C
authors.lastname: Roberts
authors.forename: Geoff J M
authors.initials: GJ
authors.lastname: Parker
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Rose
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Watson
authors.forename: James P
authors.initials: JP
authors.lastname: O'Connor
authors.forename: Stavros M
authors.initials: SM
authors.lastname: Stivaros
authors.forename: Alan
authors.initials: A
authors.lastname: Jackson
authors.forename: Vivian E
authors.initials: VE
authors.lastname: Rushton
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003287:Contrast Media; D016002:Discriminant Analysis; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010306:Parotid Gland / Q000473:pathology*; D011446:Prospective Studies; D012372:ROC Curve; D012859:Sjogren's Syndrome / Q000473:pathology*
chemical_list: D003287:Contrast Media