Combined Structural and Synovial Assessment for Improved Ultrasound Discrimination of Rheumatoid, Osteoarthritic, and Normal Joints: A Pilot Study

BACKGROUND: Current ultrasonographic scoring systems used to assess the degree of finger joint synovitis in rheumatoid arthritis (RA) are not designed for distinguishing healthy or osteoarthritis (OA) patients from those with RA in clinical settings. OBJECTIVE: To explore a novel scoring approach using structural and synovial ultrasonographic features to distinguish between healthy and OA finger joints and those with RA. METHODS: 22 patients with RA, 16 healthy controls, and 14 OA controls received a comprehensive ultrasound of one hand, with scores assigned using a modification of a previously reported RA scoring system (Semiquantitative Synovial Score), and using the novel approach (Combined Structural/Synovial Score). The number of joints classified as supporting the diagnosis of RA (“RA-supported”) with each approach was recorded. Sensitivity and specificity for each scoring system were calculated with respect to the clinical diagnosis. RESULTS: The Semiquantitative Synovial Score was highly sensitive (100%), but without specificity (0%) for the diagnosis of RA, when RA was defined as having more than 1 joint classified as “RA-supported.” The Combined Structural/Synovial Score had high sensitivity (95%) and moderate specificity (77%) when RA was defined as having any joint classified as “RA-supported”. Moderate sensitivity (73%) and high specificity (97%) were found when having more than 1 joint classified as “RA-supported” was required to diagnose RA. CONCLUSION: A novel structural and synovial hand joint scoring system was capable of distinguishing OA and healthy controls from RA subjects in this pilot evaluation. Prospective validation of this approach is planned.