Imaging signatures of distinct crystal deposition on high-frequency ultrasound for differentiating gouty arthritis and calcific tendinitis.

AIMS: To compare high-frequency ultrasound imaging signatures of crystal deposition in gouty arthritis (GA) and calcific tendinitis (CT), and explore their value in non-invasive differential diagnosis. METHODS: This single-center retrospective study enrolled 130 subjects from, including 50 GA patients, 40 CT patients and 40 healthy controls. All received standardized high-frequency ultrasound to observe lesion distribution, deposit morphology, quantitative sonographic metrics, inflammatory findings, and dynamic imaging features. We compared ultrasonic characteristics between groups, and adopted ROC curves and multivariate logistic regression to evaluate the differential diagnostic efficiency of ultrasound indicators. RESULTS: Crystal depositions were commonly detected in GA and CT patients but rarely in healthy controls. GA tended to present bilateral and multifocal lesions mainly distributed in synovium and cartilage of foot, ankle and knee joints with numerous small, shallow and irregular deposits, accompanied by obvious intra-articular inflammation. CT predominantly affected shoulder tendons, manifested as large, deep, homogeneous and highly echogenic deposits with marked posterior acoustic shadowing, together with more peritendinous inflammatory changes. Shoulder-predominant involvement yielded the highest differential diagnostic efficacy with an AUC of 0.932. CONCLUSION: High-frequency ultrasound can effectively distinguish GA from CT based on distinctive lesion distribution, crystal morphology and accompanying inflammatory manifestations, serving as a reliable non-invasive differential diagnostic tool.