title: Reproducibility of 3D delayed gadolinium enhanced MRI of cartilage (dGEMRIC) of the knee at 3.0 T in patients with early stage osteoarthritis.
abstract: OBJECTIVE
  To assess the reproducibility of 3D delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) at 3 T in early stage knee osteoarthritis (OA) patients.
  
  
  METHODS
  In 20 patients, 3D dGEMRIC at 3 T was acquired twice within 7 days. To correct for patient motion during acquisition, all images were rigidly registered in 3D. Eight anatomical cartilage ROIs were analysed on both images of each patient. Capability of dGEMRIC to yield T1 maps that reproducibly distinguish spatial differences in cartilage quality was assessed in two ROIs within a single slice in each patient. Reproducibility was assessed using ICCs and Bland-Altman plots.
  
  
  RESULTS
  ICCs ranged from 0.87 to 0.95, indicating good reproducibility. T1 maps revealed reproducible spatial differences in cartilage quality (ICC 0.79). Based on the Bland-Altman plots, we defined a threshold of 95 ms to determine if a change in dGEMRIC outcome in longitudinal research was statistically significant.
  
  
  CONCLUSIONS
  3D knee dGEMRIC at 3 T combined with 3D image registration is a highly reproducible measure of cartilage quality in early stage OA. Therefore, dGEMRIC may be a valuable tool in the non-invasive evaluation of cartilage quality changes in longitudinal research in patients with early stage OA and focal cartilage defects.
authors.affiliation: Department of Radiology, Erasmus Medical Center, Rotterdam, The Netherlands. j.vantiel@erasmusmc.nl
authors.forename: J
authors.initials: J
authors.lastname: van Tiel
authors.forename: E E
authors.initials: EE
authors.lastname: Bron
authors.forename: C J
authors.initials: CJ
authors.lastname: Tiderius
authors.forename: P K
authors.initials: PK
authors.lastname: Bos
authors.forename: M
authors.initials: M
authors.lastname: Reijman
authors.forename: S
authors.initials: S
authors.lastname: Klein
authors.forename: J A N
authors.initials: JA
authors.lastname: Verhaar
authors.forename: G P
authors.initials: GP
authors.lastname: Krestin
authors.forename: H
authors.initials: H
authors.lastname: Weinans
authors.forename: G
authors.initials: G
authors.lastname: Kotek
authors.forename: E H G
authors.initials: EH
authors.lastname: Oei
mesh_terms: D000328:Adult; D002358:Cartilage, Articular / Q000473:pathology*; D015331:Cohort Studies; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000175:diagnosis*; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA