title: Dynamic gadolinium-enhanced magnetic resonance imaging allows accurate assessment of the synovial inflammatory activity in rheumatoid arthritis knee joints: a comparison with synovial histology.
abstract: OBJECTIVE
  To determine whether dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) evaluated using semi-automatic image processing software can accurately assess synovial inflammation in rheumatoid arthritis (RA) knee joints.
  
  
  METHODS
  In 17 RA patients undergoing knee surgery, the average grade of histological synovial inflammation was determined from four biopsies obtained during surgery. A preoperative series of T(1)-weighted dynamic fast low-angle shot (FLASH) MR images was obtained. Parameters characterizing contrast uptake dynamics, including the initial rate of enhancement (IRE), were generated by the software in three different areas: (I) the entire slice (Whole slice); (II) a manually outlined region of interest (ROI) drawn quickly around the joint, omitting large artefacts such as blood vessels (Quick ROI); and (III) a manually outlined ROI following the synovial capsule of the knee joint (Precise ROI). Intra- and inter-reader agreement was assessed using the intra-class correlation coefficient (ICC).
  
  
  RESULTS
  The IRE from the Quick ROI and the Precise ROI revealed high correlations to the grade of histological inflammation (Spearman's correlation coefficient (rho) = 0.70, p = 0.001 and rho = 0.74, p = 0.001, respectively). Intra- and inter-reader ICCs were very high (0.93-1.00). No Whole slice parameters were correlated to histology.
  
  
  CONCLUSIONS
  DCE-MRI provides fast and accurate assessment of synovial inflammation in RA patients. Manual outlining of the joint to omit large artefacts is necessary.
authors.affiliation: Department of Rheumatology, Copenhagen University Hospital at Glostrup, Glostrup, Denmark. mbaxelsen@gmail.com
authors.forename: M B
authors.initials: MB
authors.lastname: Axelsen
authors.forename: M
authors.initials: M
authors.lastname: Stoltenberg
authors.forename: R P
authors.initials: RP
authors.lastname: Poggenborg
authors.forename: O
authors.initials: O
authors.lastname: Kubassova
authors.forename: M
authors.initials: M
authors.lastname: Boesen
authors.forename: H
authors.initials: H
authors.lastname: Bliddal
authors.forename: K
authors.initials: K
authors.lastname: Hørslev-Petersen
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; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging; D019645:Arthroplasty, Replacement, Knee; D003287:Contrast Media; D005260:Female; D005682:Gadolinium; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007719:Knee Joint / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011877:Radionuclide Imaging; D015203:Reproducibility of Results; D013585:Synovitis / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology; D055815:Young Adult
chemical_list: D003287:Contrast Media; D005682:Gadolinium