The Value of an Automated Ultrasound System in the Detection of Synovitis

BACKGROUND: The detection of joint swelling caused by synovitis is important for the diagnosis of inflammatory arthritis. Ultrasound (US) and MRI have proven to be more sensitive and reliable than physical examination, but they are time-consuming and expensive. The automated breast volume scanner was developed to acquire serial B-mode pictures of the female breast and these can be analyzed in all three dimensions. OBJECTIVES: To analyze the value of automated B-mode ultrasound employing the ABVS system in detecting synovitis of the finger joints compared to manual ultrasound (mUS) and physical examination, using MRI as the gold standard. METHODS: 19 consecutive patients suffering from active rheumatoid (n=15) or psoriatic (n=4) arthritis were included. Automated and mUS were conducted with a linear array (ACUSON S2000™, 11 MHz). Multiplanar reconstruction enabled examination of the images for the presence of synovitis. RESULTS: 90% of the hand joints were assessable by automated ultrasound. Automated US detected 12.0, mUS 14.2, MRI 13.4, and clinical examination 4.1 positive joints – i. e. joints with synovitis - on average per patient. The inter-observer reliability of both assessors for automated and mUS, MRI, and physical examination, was 66.9%, 72.7%, 95.1%, and 88.9%, respectively. 84.3% of the joints classified as positive on MRI were confirmed by automated ultrasound, 85.5% on mUS, and 36.0 on physical examination. This translated into a sensitivity of 83.5%, 85.5%, and 36.0% for the three methods, respectively. Conclusion: Automated ultrasound is a promising ultrasound method for assessing small joints in patients with inflammatory arthritis.