title: Reliability and responsiveness of dynamic contrast-enhanced magnetic resonance imaging in rheumatoid arthritis.
abstract: OBJECTIVE
  To investigate the responsiveness to treatment and the reliability of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in rheumatoid arthritis (RA) knee joints.
  
  
  METHODS
  DCE-MRI was performed in 12 clinically active RA knee joints before and 1, 7, 30, and 180 days after intra-articular injection with 80 mg methylprednisolone. Using semi-automated image processing software, DCE-MRI parameters, including the initial rate of enhancement (IRE) and maximal enhancement (ME), were generated for three regions of interest (ROIs): 'Whole slice', 'Quick ROI', and 'Precise ROI'. The smallest detectable difference (SDD), the smallest detectable change (SDC), and intra- and inter-reader intraclass correlation coefficients (ICCs) were used to assess the reliability of DCE-MRI. Responsiveness to treatment was assessed by the standardized response mean (SRM).
  
  
  RESULTS
  In all patients clinical remission of the knee was achieved at day 7. All DCE-MRI parameters decreased from day 0 to day 7. Using the Quick and Precise ROI methods, respectively, IRE decreased by 63% and 69%, ME decreased by 11% and 11%, N decreased by 55% and 57%, and IRE × N decreased by 84% and 85%. The intra- and inter-reader ICCs were very high (0.96-1.00). The decrease in DCE-MRI parameters was larger than the SDC for all patients. SRM was large for all parameters, ranging from -1.04 to -2.40. When the Whole slice ROI method was used, no parameters were responsive to treatment.
  
  
  CONCLUSIONS
  DCE-MRI analysed using semi-automatic software is a reliable and responsive tool for assessing treatment in RA knees joints. Rough manual delineation of the joint to omit enhancement artefacts is necessary.
authors.affiliation: Copenhagen Center for Arthritis Research, Center for Rheumatology and Spine Diseases, Copenhagen University Hospital at Glostrup, Denmark. mbaxelsen@gmail.com
authors.forename: M B
authors.initials: MB
authors.lastname: Axelsen
authors.forename: R P
authors.initials: RP
authors.lastname: Poggenborg
authors.forename: M
authors.initials: M
authors.lastname: Stoltenberg
authors.forename: O
authors.initials: O
authors.lastname: Kubassova
authors.forename: M
authors.initials: M
authors.lastname: Boesen
authors.forename: K
authors.initials: K
authors.lastname: Hørslev-Petersen
authors.forename: H
authors.initials: H
authors.lastname: Bliddal
authors.forename: L G
authors.initials: LG
authors.lastname: Hanson
authors.forename: M
authors.initials: M
authors.lastname: Østergaard
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000175:diagnosis* / Q000188:drug therapy; D015331:Cohort Studies; D005500:Follow-Up Studies; D019786:Gadolinium DTPA; D005938:Glucocorticoids / Q000008:administration & dosage*; D006801:Humans; D007089:Image Enhancement; D007270:Injections, Intra-Articular; D007719:Knee Joint / Q000187:drug effects / Q000473:pathology*; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008775:Methylprednisolone / Q000008:administration & dosage*; D008875:Middle Aged; D012008:Recurrence; D012074:Remission Induction; D015203:Reproducibility of Results; D013585:Synovitis / Q000175:diagnosis* / Q000188:drug therapy; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D005938:Glucocorticoids; D019786:Gadolinium DTPA; D008775:Methylprednisolone