title: Feasibility and reproducibility of the PsAMRIS-H score for psoriatic arthritis in low-field-strength dedicated extremity magnetic resonance imaging.
abstract: OBJECTIVE
  The psoriatic arthritis magnetic resonance imaging scoring system (PsAMRIS-H) for the evaluation of inflammatory and destructive changes in PsA hands was validated on 0.6-T scanners. The applicability of the PsAMRIS-H on a low-field MRI system as a well-accepted, low-cost imaging modality was evaluated.
  
  
  METHODS
  In 65 consecutive patients (31 males, median age 52 years), 73 scans on a 0.2-T dedicated extremity MRI system were obtained for evaluation of PsA. Images were scored for synovitis, tenosynovitis, periarticular enhancement, bone erosion, bone oedema, and proliferation, and the PsAMRIS-H score was calculated. The intraclass correlation coefficient (ICC) was calculated and the paired t-test conducted.
  
  
  RESULTS
  Intra-reader reliability for the total PsAMRIS-H score was good, with an ICC of 0.81 and 0.77 for readers 1 and 2, respectively, and inter-reader agreement was moderate (0.57 for each reader). However, the PsAMRIS-H score differed significantly between the two readers (22 vs. 31; p < 0.05). When individual components of the PsAMRIS were evaluated, intra- and inter-reader agreement was poor to moderate, especially for tenosynovitis and periarticular inflammation.
  
  
  CONCLUSIONS
  Low-field 0.2-T MRI is capable of quantifying the PsAMRIS-H with good intra-reader reproducibility. However, low signal-to-noise ratio (SNR), low spatial resolution, and system artefacts limit the application of the PsAMRIS-H, leading to low inter- and intra-reader agreement for individual features.
authors.affiliation: Institute for Clinical Radiology and Ludwig-Maximilians-University Hospital Munich , Germany.
authors.forename: H
authors.initials: H
authors.lastname: Strube
authors.forename: C
authors.initials: C
authors.lastname: Becker-Gaab
authors.forename: T
authors.initials: T
authors.lastname: Saam
authors.forename: M
authors.initials: M
authors.lastname: Reiser
authors.forename: S
authors.initials: S
authors.lastname: Schewe
authors.forename: H
authors.initials: H
authors.lastname: Schulze-Koops
authors.forename: M
authors.initials: M
authors.lastname: Treitl
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015535:Arthritis, Psoriatic / Q000473:pathology*; D018450:Disease Progression; D004487:Edema / Q000473:pathology; D005240:Feasibility Studies; D005260:Female; D005384:Finger Joint / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013585:Synovitis / Q000473:pathology; D013717:Tenosynovitis / Q000473:pathology; D055815:Young Adult