Usefulness of the Automated Bone Scan Index in Arthritis: A Quantitative Approach for Evaluating Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis (SAPHO) Syndrome

For several decades, bone scintigraphy (BS) has been used as a diagnostic tool for arthritis in patients with synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome. Artificial intelligence (AI) diagnostic supporting systems are effective in BS. The bone scan index (BSI) on BS with AI diagnostic support systems has been used for bone tumors. However, its application in arthritis has not been validated. The current study aimed to evaluate the usefulness of BSI using an AI diagnostic supporting system for arthritis in patients with SAPHO syndrome.

The regional BSI (rBSI) of arthritis uptake around the sternoclavicular and sternocostal joints on BS in patients with SAPHO syndrome was calculated using an AI diagnostic supporting system (VSBONE BSI®). For comparison, patients with degenerative changes on BS in the same region were evaluated. rBSI was calculated using the same process.

This study included 43 patients with SAPHO syndrome and 48 with degenerative changes. The rBSIs with the diagnostic supporting system were 0.19 ± 0.19 in patients with SAPHO syndrome and 0.043 ± 0.056 in those with degenerative changes. Patients with SAPHO syndrome had significantly higher rBSIs than those with degenerative changes (P < 0.001). A cutoff value of 0.030 for rBSI in the region of interest had a sensitivity of 0.98 and specificity of 0.63 for differentiating arthritis from degenerative changes (area under the curve: 0.87, 95% confidence interval: 0.81–0.92).

The objective evaluation of arthritis using rBSI calculated with an AI diagnostic supporting system may be useful.