An automatic model-based system for joint space measurements on hand radiographs: initial experience.

This ethics committee-approved pilot study was performed with informed consent. A Web-based service that was developed for automated measurement of joint space and automatic analysis of radiographs was tested prospectively. A total of 160 metacarpophalangeal joint spaces were measured in 20 patients (average age, 48 years; age range, 18-89 years; 16 women) suspected of having rheumatoid arthritis or osteoarthritis. The technical success rate was 93%. The smallest detectable difference in repeated automatic joint space width measurements varied from 0.08 to 0.31 mm, and the coefficient of variation was 2%-7%. Compared with the reference standard (interactive segmentation of the joint space widths) measurements, results were within a mean error of 0.19-0.40 mm. The proposed Web-based service enables reproducible joint space measurements to be obtained in metacarpophalangeal joints with moderate erosive and osteophytic disease.