Self-reported diagnostic confidence predicts diagnostic accuracy in axial spondyloarthritis imaging

Objectives: Reporting diagnostic confidence (DC) in axial spondyloarthritis (axSpA) imaging is recommended by the ASAS guidelines. Our aim was to investigate whether self-reported DC predicts diagnostic accuracy in axSpA imaging using X-ray (XR), computed tomography (CT) and magnetic resonance imaging (MRI).Methods: We performed a post hoc analysis including 163 patients with low back pain (89 axSpA and 56 non-axSpA). Nine blinded readers with different experience levels [inexperienced (<1 year), semi-experienced (3-8 years) and experienced (>12 years)] scored the sacroiliac joint images for compatibility with axSpA. DC was reported on a scale from 1 (not sure) to 10 (very sure). Mean DC scores and standard deviations were calculated for correct and incorrect responses using XR, CT, MRI, XR+MRI and CT+MRI. Differences in DC were assessed using the Mann-Whitney U test.Results: DC scores were higher for correct axSpA diagnoses and differed significantly between correct and incorrect responses for all modalities (P < 0.001), with a mean DC of 7.1 +/- 2.1 and 6.3 +/- 2.1 for XR, 8.3 +/- 1.8 and 6.7 +/- 2.0 for CT, 8.1 +/- 1.9 and 6.2 +/- 1.9 for MRI, 8.2 +/- 1.8 and 6.7 +/- 1.8 for XR+MRI and 8.4 +/- 1.8 and 6.8 +/- 1.8 for CT+MRI, respectively. This was also the case when looking at the results by experience group, except for XR in the inexperienced group.Conclusion: Providing self-reported DC in radiological reports is useful information to predict diagnostic reliability in axSpA imaging.