Positive rate and prognostic significance of the superb microvascular imaging signal in joints of rheumatoid arthritis patients in remission with normal C-reactive protein levels and erythrocyte sedimentation rates.

In RA patients in remission with normal CRP and ESR levels, the percentage of positive SMI signal was highest in the wrist joints. However, the accuracy of the SMI signal for predicting relapse was greatest for the MTP joints, suggesting that US assessment of the MTP joints by SMI is useful for predicting relapse in these patients.