The incremental value of spinal MRI in axial spondyloarthritis: Impactful or ineffectual?

To report on the incremental value of MRI spine findings on the radiologic diagnostic certainty in axial spondyloarthritis.

MRI examinations of suspected axial spondyloarthritis patients referred from a specialist tertiary rheumatology clinic were collected retrospectively. 29 patients and 10 controls were randomized and analyzed by three blinded musculoskeletal radiologists. Linear regression analyses were used to evaluate the association of spine and SIJ findings on diagnostic certainty levels.

Mean patient age was 43.3 [range: 15-71] years. Good and excellent intra-observer agreement was demonstrated [κ = 0.8, 1] for SIJ and spinal lesions, while inter-observer agreement on final certainty was moderate [κ = 0.5]. SIJ structural lesions significantly impacted final certainty levels [p=0.03]. However, SIJ inflammatory changes and a combination of the two did not meet statistical significance [p=0.42, 0.40]. Combination of spinal structural and inflammatory findings had a significant impact on final diagnosis [p<0.01].

Our study highlights the diagnostic added value of spinal MRI. Spinal findings had a significant impact on the final diagnostic certainty level of radiologists; it reduces the level of uncertainty posed by SIJ inflammatory lesions. The findings suggest that spinal MRI has an important role in the diagnostic work up of Axial Spondyloarthritis.