Proposal Of A Preliminary Magnetic Resonance Imaging (MRI) Scoring System In Hand Osteoarthritis (HOA)

I.K. Haugen1, S. Lillegraven1, B. Slatkowsky-Christensen1, E. Haavardsholm1, T.K. Kvien1, D. van der Heijde1 2, S. Sesseng3, P. Bøyesen1 1Dept. of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway; 2Dept. of Rheumatology, Leiden University Medical Center, Leiden, Netherlands; 3Dept. of Radiology, Diakonhjemmet Hospital, Oslo, Norway

Background: Conventional radiograph is the preferred method for evaluation of HOA, but MRI is receiving more interest. However, there exists no validated scoring system for MRI in HOA.

Objectives: To propose definitions of features to be included in the HOA MRI scoring system based on the features included the MRI scoring system in psoriatic arthritis (PsA) (1) and the OARSI atlas for radiographs in HOA (2).

Methods: Relevant features (synovitis, flexor tenosynovitis, bone erosions, bone marrow edema and bony proliferations) from PsAMRIS were included in the HOA MRI scoring system after eventual modifications. Of the radiological OA features from the OARSI atlas, joint space narrowing (JSN), cysts and malalignment were included, in addition to evaluation of the presence, thickness and bone marrow lesions at insertion sites of the collateral ligaments. The available MRI sequences included T1w with fat suppression (fs) (axial, sagittal and coronal) pre- and post gadolinium (Gd), and short TI inversion recovery (STIR) (axial and coronal).

Results: The definitions of synovitis (grade 0-3), flexor tenosynovitis (grade 0-3), bone erosions (grade 0-10) and bone marrow edema (grade 0-3) were equal to the PsAMRIS definitions. "Bone marrow edema" was changed to "bone marrow lesions" (BML). The definition of cysts was similar to the definition of erosions, but without any cortical break. Bony proliferations were scored on a 0-3 scale as in the OARSI atlas rather than 0-1 as in PsAMRIS. JSN and malalignment were similarly scored as in the OARSI atlas on a 0-3 scale and 0-1 scale, respectively. The scoring of the collateral ligaments included scoring of absence/presence (grade 0-1), thickening (grade 0-1) and BML at insertion sites (grade 0-1). All features should be scored in the distal interphalangeal (DIP) and proximal interphalangeal (PIP) joints of the 2nd-5th fingers. Erosions, cysts, BML and bony proliferation should be scored in the proximal and distal part of the joint separately. The collateral ligaments should be scored separately in both the radial and ulnar part of the joint, while malalignment should scored separately in both the frontal and sagittal plane. The STIR sequence was used for assessment of BML, while the T1w fs images were used for assessment of the other features.

Conclusion: The proposed MRI scoring system in HOA included scoring of synovitis, flexor tenosynovitis, extensor tendinitis, bone erosions, bone cysts, bone marrow lesions, bone proliferations, joint space narrowing and the presence and thickening of the collateral ligaments. Validation in the Oslo HOA cohort is ongoing.

References:

• Østergaard M, McQueen F, Wiell C, Bird P, Bøyesen P, Ejbjerg B, et al. The OMERACT psoriatic arthritis magnetic resonance imaging scoring system (PsAMRIS): definitions of key pathologies, suggested MRI sequences, and preliminary scoring system for PsA Hands. J Rheumatol 2009 Aug;36(8):1816-24.
• Altman RD, Gold GE. Atlas of individual radiographic features in osteoarthritis, revised. Osteoarthritis Cartilage 2007;15 Suppl A:A1-56.

Disclosure of Interest: None declared

Citation: Ann Rheum Dis 2010;69(Suppl3):310

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