 The main goal of RA treatment is to achieve disease remission. The treatment of RA consists of synthetic and biologic disease modifying drugs DMARDs, being the second ones selected when low disease or remission is not achieved with the first ones. Therapeutic response monitoring in RA should be closely managed. It is classically based on clinical exploration and laboratory tests. During the last decade, the resolution improvement of musculoskeletal ultrasound MSUS imaging has led to the gradual incorporation of this technique in the evaluation and monitoring of patients with RA, mainly due to its better capacity to detect synovitis than clinical exploration . Ultrasound imaging is highly available, non-invasive, reproducible, affordable and well accepted by patients. Ultrasound doppler mode detects pathological synovial flow, which reflects synovial inflammation and has a demonstrated sensitivity to change in multiple longitudinal studies. Sonographic evaluation of patients with RA includes the detection of synovitis in B and Doppler mode in the joints accessible by ultrasound. There has been high variability in the literature regarding the number of joints that should be evaluated for an appropriate monitoring of the RA patients. The validity for monitoring the therapeutic response in long standing RA has been demonstrated in three reduced joint counts, including 12, 7 and 6 joints. However, in shorter evolution RA, the sensitivity to change of any of these reduced ultrasound evaluations has never been studied 