MRI lesions in spa: a comparison with age and sex matched participants with non-inflammatory back pain

Abstract

Background: Magnetic resonance imaging (MRI) is becoming increasingly important in axial spondyloarthritis (SpA) due to its unique role in early diagnosis, classification, and monitoring of disease (1, 2). It is the only disease assessment tool that has been validated with histological inflammatory cellularity in tissue biopsy of the sacroiliac (SI) joint (3). However, many MRI lesions are not exclusive to axial SpA and may occur in other conditions such as infection, degeneration and malignancy. Further characterization of these lesions may guide more targeted therapies.

Objectives: The objective of this study was to describe, investigate associated factors, and to compare individual MRI lesions with age and sex matched controls.

Methods: This was a cross-sectional observational study of MRI lesions of 431 participants with axial SpA compared with 53 age and sex matched participants with non-inflammatory back pain. Individual lesions identified included: discovertebral lesions (DVL), facet joint lesions, costovertebral joint lesions, corner inflammatory lesions (CIL), and fatty corner lesions (FCL). Associated factors of the lesions were determined by regression analyses.

Results: Compared to the control group, participants with axial SpA had more costovertebral lesions (12.5% vs 1.9%; p=0.02), CIL (46.6% vs 15.1%; p=0.03), and FCL (55.5% vs 39.6%; p=0.03). Multivariate regression showed that age (OR=1.02; p=0.03), regular alcohol use (OR=0.40; p=0.04) and radiographic axial SpA (OR=1.89; p=0.01) were associated with DVL; Chinese ethnicity (OR=0.06; p=0.01) and radiographic axial SpA (OR=3.63; p=0.01) were associated with facet joint lesion; radiographic axial SpA (OR=4.26; p<0.001) was associated with costovertebral joint lesion; male gender (ß=1.10; p=0.01), HLA B27 (ß=1.02; p=0.02), and radiographic axial SpA (ß=1.05; p=0.01) were associated with CIL; age (ß=0.10; p<0.01), male gender (ß=1.96; p=0.01), body weight (ß=0.11; p<0.01), HLA B27 (ß=3.23; p<0.001), and radiographic axial SpA (ß=1.77; p=0.02) were associated with FCL.

Conclusion: The individual MRI lesions more specific to axial SpA when compared to non-inflammatory back pain were costovertebral joint lesions, CIL, and FCL.