The role of ultrasound in diagnosing rheumatoid arthritis, what do we know? An updated review.

To clarify if musculoskeletal ultrasound (MSUS) improves early diagnosis of RA when added to the clinical examination of patients with possible arthritis. We performed a systematic literature review of original studies dealing with the value of MSUS in the early diagnosis of RA. Studies were identified using the databases of PubMed, EMBASE and Cochrane library. Only studies in English investigating populations with non-classified arthritis or arthralgia were included. Fifteen original studies investigating the added value of MSUS in diagnosing RA were identified. They differed in sample size, study population, serology status, number of joints investigated and regarding the ultrasound machines and probes used. Thirteen out of 15 studies concluded that use of MSUS had an added value compared to clinical examination and laboratory evaluation alone for diagnosing RA. One study found that MSUS did not add substantial discriminatory value for predicting RA in an early arthritis cohort when added to routine assessment. However, in this study only 16 joints were examined (wrists and MTP 3-5 were not included). One study investigated only seropositive patients and found no significant advantage of MSUS on patient level although a trend was noted. Accordingly, two other studies found MSUS to be useful especially in seronegative patients. The use of MSUS adds value in diagnosing early RA, especially in seronegative arthritis. However, no study to date has documented any effect of DMARD initiation based on MSUS findings (subclinical arthritis) alone. More studies investigating this matter are warranted.