Arthritis & Rheumatism, Volume 60,
October 2009 Abstract Supplement

The 2009 ACR/ARHP Annual Scientific Meeting
Philadelphia October 16-21, 2009.


Reader Reliability of the OMERACT Psoriatic Arthritis Magnetic Resonance Score (PsAMRIS): Results From An OMERACT Workshop

Boyesen1,  Pernille, Gandjbakhch2,  Frédérique, McQueen3,  Fiona M., Lillegraven4,  Siri, Coates5,  Laura, Wiell6,  Charlotte, Conaghan7,  Philip

MD, Oslo, Norway
MD, Paris, France
University of Auckland, Auckland, New Zealand
Diakonhjemmet Hospital, Oslo, Norway
University of Leeds, Leeds, United Kingdom
MD, Hvidovre, Denmark
Leeds, United Kingdom
Hvidovre and Gentofte, Denmark

Purpose:

The aim of this study was to test cross-sectional and longitudinal inter- and intra reader reliability of the Psoriatic Arthritis Magnetic Resonance Imaging Score (PsAMRIS) under standardized conditions.

Methods:

The exercise was performed using MRI scans from 12 PsA patients (8 acquired in Copenhagen and 4 in Leeds) before and after 12 months of anti-TNFa therapy. The metacarpophalangeal (MCP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) joints of the 2nd–5th fingers were examined, using a 0.6 T MRI unit (Copenhagen) and a 0.2T MRI unit (Leeds). Coronal, axial and sagittal T1-weighted pre- and post-gadolinium-contrast images and sagittal and axial pre-contrast STIR images were obtained, anonymized and blinded for time sequence and read twice by FG, FMQ, MØ and PB on identical PACS workstations. For the second reading the images were re-anonymized and re-randomised. The images were scored according to the PsAMRIS: at MCP, PIP and DIP joint-level synovitis was scored 0–3, tenosynovitis 0–3, bone proliferation 0–2, pariarticular inflammation 0–2, bone marrow edema 0–3 per bone and bone erosions 0–10 per bone. Inter-reader reliability was assessed using average measure intraclass correlations coefficient (ICCa) and intra-reader reliability by single measures intraclass correlations coefficient (ICCs).

Results:

The median (IQR) average baseline/1-year follow-up synovitis score was 10.8 (8.5–14.3)/8.4 (6.7–9.7), tenosynovitis score 5.7 (1.7–8.5)/2.0 (0.9–4.4), bone proliferation 2.2 (1.4–3.9)/2.2 (1.4–3.9), periarticular inflammation 1.1 (0.1–3.6)/0.5 (0.3–0.6), bone marrow edema 0.3 (0.1–1.4)/0.1 (0.0–0.8) and bone erosions 1.8 (0.2–5.1)/1.9 (0.1–5.0). The cross-sectional inter-and intra reader reliability as well as the inter-reader reliability for 1-year change are presented in table 1. The inter-reader ICC was high for all measures except moderate for bone proliferation. Poor ICCs for bone proliferation and erosion change scores are explained by minimal change in the 1-year period.

Table 1. Cross sectional inter- and intra reader reliability

  Inter-reader reliability (ICCa)Intra-reader reliability (ICCs) (cross-sectional)
 Cross-sectional1-year changeReader 1Reader 2Reader 3Reader 4
PsA synovitis0.950.950.970.730.930.90
PsA flexor tenosynovitis0.970.950.810.740.930.73
PsA bone proliferation0.770.100.200.840.790.44
PsA periarticular inflammation0.910.910.390.950.880.91
PsA bone marrow edema0.870.870.980.970.990.03
PsA bone erosion0.970.440.910.930.920.91

Conclusion:

In this multi-reader exercise testing the PsAMRIS under standardized conditions, very high interreader and intrareader reliability for status and change scores for most parameters and readers were found. Inflammatory parameters performed best. These results suggest that PsAMRIS is a reliable tool for MRI assessment of PsA patients.

To cite this abstract, please use the following information:
Boyesen, Pernille, Gandjbakhch, Frédérique, McQueen, Fiona M., Lillegraven, Siri, Coates, Laura, Wiell, Charlotte, et al; Reader Reliability of the OMERACT Psoriatic Arthritis Magnetic Resonance Score (PsAMRIS): Results From An OMERACT Workshop [abstract]. Arthritis Rheum 2009;60 Suppl 10 :777
DOI: 10.1002/art.25857

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