Objective: To assess the diagnostic value for axial spondyloarthritis (SpA) of unilateral sacroiliitis in scintigraphy in daily clinical practice.
Methods: In 207 patients with chronic back pain, the diagnostic value of scintigraphy was assessed retrospectively. The diagnosis made by the rheumatologist (axial SpA vs no axial SpA) was the standard.
Results: Sensitivities of scintigraphy for any (unilateral or bilateral), bilateral, and isolated unilateral sacroiliitis were 64.9%, 40.2%, and 24.7%, respectively. Respective specificities were 50.5%, 57.7%, and 92.8%, resulting in likelihood ratios of 1.3, 1.0, and 3.4.
Conclusion: Scintigraphy of the sacroiliac joints is of limited value for the diagnosis of axial SpA. Unilateral compared to bilateral sacroiliitis is slightly superior, but is associated with a low sensitivity.