Daria Motamedi1, Rina Patel2, Kavi K Devulapalli2, Lianne S Gensler3, Lynne Steinbach2. 1. Department of Radiology and Biomedical Imaging, Musculoskeletal Division, University of California San Francisco, United States of America. Electronic address: daria.motamedi@ucsf.edu. 2. Department of Radiology and Biomedical Imaging, Musculoskeletal Division, University of California San Francisco, United States of America. 3. Department of Medicine, Rheumatology Division, University of California San Francisco, United States of America.
Abstract
OBJECTIVE: Evaluate the MR distribution of inflammatory sacroiliac joint changes in axial spondyloarthritis phenotypes, including Ankylosing Spondylitis (AS) and non-radiographic Axial Spondyloarthritis (nrAxSpA). METHODS: A retrospective review of 94 patients seen for treatment of axial spondyloarthritis (SpA) who underwent sacroiliac joint MRI between January 2011 and December 2015 was performed. MR images from 68 patients (20 with AS and 48 with nrAxSpA) were reviewed independently by two radiologists. Images were scored on presence of active inflammatory and chronic structural lesions. These lesions were further categorized as unilateral, bilateral and asymmetric, or bilateral and symmetric. RESULTS: No statistically significant difference was found in the distribution (laterality or symmetry) of bone marrow edema or sclerosis between the AS and nr-axSpA groups. Osseous erosions were more commonly bilateral symmetric in AS than nr-axSpA (11/20 vs. 8/48, p = 0.01). No statistically significant difference was noted between bone marrow edema scores in the AS and nr-axSpA subgroups (2.6 vs 3.3, p = 0.514). Patients with AS had a significantly higher fat metaplasia score compared to patients with nr-axSpA (7.3 vs 1.1, p = 0.001). Patients with nr-axSpA had a higher mean score for erosions (11.6 vs 4.2, p = 0.001). Only patients classified as AS were found to have bony ankylosis. Inter-observer reliability was strong to excellent. CONCLUSION: Ankylosing spondylitis findings at the sacroiliac joints are classically described as bilateral and symmetric on radiographs. Our study demonstrates that distribution on MRI at an individual time point is variable. The variable distribution should be considered when radiologists evaluate MRI exams of AS patients.
OBJECTIVE: Evaluate the MR distribution of inflammatory sacroiliac joint changes in axial spondyloarthritis phenotypes, including Ankylosing Spondylitis (AS) and non-radiographic Axial Spondyloarthritis (nrAxSpA). METHODS: A retrospective review of 94 patients seen for treatment of axial spondyloarthritis (SpA) who underwent sacroiliac joint MRI between January 2011 and December 2015 was performed. MR images from 68 patients (20 with AS and 48 with nrAxSpA) were reviewed independently by two radiologists. Images were scored on presence of active inflammatory and chronic structural lesions. These lesions were further categorized as unilateral, bilateral and asymmetric, or bilateral and symmetric. RESULTS: No statistically significant difference was found in the distribution (laterality or symmetry) of bone marrow edema or sclerosis between the AS and nr-axSpA groups. Osseous erosions were more commonly bilateral symmetric in AS than nr-axSpA (11/20 vs. 8/48, p = 0.01). No statistically significant difference was noted between bone marrow edema scores in the AS and nr-axSpA subgroups (2.6 vs 3.3, p = 0.514). Patients with AS had a significantly higher fat metaplasia score compared to patients with nr-axSpA (7.3 vs 1.1, p = 0.001). Patients with nr-axSpA had a higher mean score for erosions (11.6 vs 4.2, p = 0.001). Only patients classified as AS were found to have bony ankylosis. Inter-observer reliability was strong to excellent. CONCLUSION:Ankylosing spondylitis findings at the sacroiliac joints are classically described as bilateral and symmetric on radiographs. Our study demonstrates that distribution on MRI at an individual time point is variable. The variable distribution should be considered when radiologists evaluate MRI exams of AS patients.
Authors: Rosa Marie Kiil; Clara E Mistegaard; Anne Gitte Loft; Anna Zejden; Oliver Hendricks; Anne Grethe Jurik Journal: Arthritis Res Ther Date: 2022-03-24 Impact factor: 5.156