MRI lesions of the spine in patients with axial spondyloarthritis: an update of lesion definitions and validation by the ASAS MRI working group

Xenofon Baraliakos; Mikkel Østergaard; Robert Gw Lambert; Iris Eshed; Pedro M Machado; Susanne Juhl Pedersen; Ulrich Weber; Manouk de Hooge; Joachim Sieper; Denis Poddubnyy; Martin Rudwaleit; Désirée van der Heijde; Robert Bm Landewé; Walter P Maksymowych

doi:10.1136/annrheumdis-2021-222081

MRI lesions of the spine in patients with axial spondyloarthritis: an update of lesion definitions and validation by the ASAS MRI working group

Ann Rheum Dis. 2022 Aug 11;81(9):1243-1251. doi: 10.1136/annrheumdis-2021-222081.

Authors

Xenofon Baraliakos¹, Mikkel Østergaard², Robert Gw Lambert³, Iris Eshed⁴, Pedro M Machado^{5

6

7}, Susanne Juhl Pedersen², Ulrich Weber⁸, Manouk de Hooge⁹, Joachim Sieper¹⁰, Denis Poddubnyy¹⁰, Martin Rudwaleit¹¹, Désirée van der Heijde¹², Robert Bm Landewé¹³, Walter P Maksymowych¹⁴

Affiliations

¹ Rheumazentrum Ruhrgebiet Herne, Ruhr-University Bochum, Bochum, Germany.
² Copenhagen Center for Arthritis Research, Center for Rheumatology and Spine Diseases, Rigshospitalet, Glostrup and Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.
³ Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Canada and Medical Imaging Consultants, Edmonton, Alberta, Canada.
⁴ Department of Diagnostic Imaging, Sheba Medical Center, affiliated to the Sackler school of medicine, Tel-Aviv University, Tel Aviv, Israel.
⁵ Department of Rheumatology, University College London, London, UK.
⁶ Centre for Rheumatology and MRC Centre for Neuromuscular Diseases, University College London, London, UK.
⁷ Department of Rheumatology, Northwick Park Hospital, London North West University Healthcare NHS Trust, London, UK.
⁸ Practice Buchsbaum, Rheumatology, Schaffhausen, Switzerland.
⁹ VIB Inflammation Research Center, Ghent University, Ghent, Belgium and Rheumatology Department, Ghent University Hospital, Gent, Belgium.
¹⁰ Charité - Universitätsmedizin Berlin and German Rheumatism Research Centre, Berlin, Germany.
¹¹ Klinikum Bielefeld, University of Bielefeld, Bielefeld, Germany.
¹² Leiden University Medical Center, Leiden, The Netherlands.
¹³ Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands, and Atrium Medical Center, Heerlen, The Netherlands.
¹⁴ Department of Medicine, University of Alberta, Edmonton, Canada; CARE Arthritis, Edmonton, Alberta, Canada [email protected].

PMID: 35609977
DOI: 10.1136/annrheumdis-2021-222081

Abstract

Objectives: Spinal MRI is used to visualise lesions associated with axial spondyloarthritis (axSpA). The ASAS MRI working group (WG) updated and validated the definitions for inflammatory and structural spinal lesions in the context of axSpA.

Methods: After review of the existing literature on all possible types of spinal MRI pathologies in axSpA, the group (12 rheumatologists and two radiologists) consented on the required revisions of lesion definitions compared with the existing nomenclature of 2012. In a second step, using 62 MRI scans from the ASAS classification cohort, the proposed definitions were validated in a multireader campaign by global (absent/present) and detailed (inflammation and structural) lesion assessment at the vertebral corner (VC), vertebral endplate, facet joints, transverse processes, lateral and posterior elements. Intraclass correlation coefficient (ICC) was used for analysis.

Results: Revisions were made for both inflammatory (bone marrow oedema, BMO) and structural (fat, erosion, bone spur and ankylosis) lesions, including localisation (central vs lateral), extension (VC vs vertebral endplate) and extent (minimum number of slices needed), while new definitions were suggested for the type of lesion based on lesion maturity (VC monomorphic vs dimorphic). The most reliably assessed lesions were VC fat lesion and VC monomorphic BMO (ICC (mean of all 36 reader pairs/overall 9 readers): 0.91/0.92; 0.70/0.67, respectively.

Conclusions: The lesion definitions for spinal MRI lesions compatible with SpA were updated by consensus and validated by a group of experienced readers. The lesions with the highest frequency and best reliability were fat and monomorphic inflammatory lesions at the VC.

Keywords: Inflammation; Magnetic Resonance Imaging; Spondylitis, Ankylosing.