Sonographic cutoff values for detection of abnormalities in small, medium and large joints: a comparative study between patients with rheumatoid arthritis and healthy volunteers.

To determine ultrasound measurements indicative of abnormalities in small, medium and large joints, we conducted a cross-sectional study comparing 60 patients with rheumatoid arthritis (RA) and 78 healthy volunteers. A MyLab 60 ultrasound machine (Esaote) and a linear multifrequency probe were used. Quantitative measurements of synovial recesses and semiquantitative measurements of synovial hyperplasia, power Doppler and bone erosion (scores = 0-3) were performed. The cutoff values for synovial recesses indicating RA (receiver operating characteristic curve, area under the curve >0.800) were found to be (radiocarpal) 3.78 mm and (ulnocarpal) 3.07 mm. Those measurements with the greatest chance of indicating RA (logistic regression analysis expressed as odds ratios [ORs]) were (p < 0.001) measurements of synovial hyperplasia (ulnocarpal, OR = 100, and radiocarpal, OR = 70); synovial power Doppler (radiocarpal, OR = 66); synovial bone erosion (radiocarpal, OR = 324); fifth metatarsophalangeal joint (OR = 100); and second metacarpophalangeal joint (OR = 92). We concluded that for both quantitative and semiquantitative ultrasound measurements, radiocarpal abnormalities increase the chance of detecting RA.