General Applications of Ultrasound in Rheumatology Practice

Over the past 2 decades, an increasing number of rheumatologists have progressively incorporated ultrasound (US) as an invaluable diagnostic and monitoring tool into their clinical and research practice. ^1,2 This imaging modality has become an established aid incorporated into the clinical evaluation of periarticular and articular structures involved in the diagnosis of several rheumatic disorders.

Ultrasound is a safe, noninvasive, patient-friendly imaging modality with a lack of contraindications and free of ionizing radiation. It allows real-time evaluation with dynamic assessment in a multiplanar view, assessment of multiple targets, and lower cost compared with magnetic resonance imaging (MRI) or computerized tomography scan. Above all, for the rheumatologist, US provides real-time scanning of all peripheral joints as many times as is required at the time of consultation. It is of great advantage in the assessment of a wide spectrum of abnormalities in rheumatic diseases with the potential of point-of-care imaging modality in the clinical evaluation and management of the patient. It facilitates a direct correlation between imaging findings and clinical data that improves the approach to a wide range of rheumatic diseases, from acute to chronic inflammatory arthritis, crystalline arthropathies, osteoarthritis (OA), spondyloarthropathies (SpA), vasculitis, and soft tissue syndromes. In addition, US is a bedside tool for performing accurate and safe diagnostic arthrocentesis, injections, and synovial biopsies. ^3,4

Recently, a gradual attempt has been made to incorporate US into rheumatology disease classification or diagnostic criteria for rheumatoid arthritis (RA), polymyalgia rheumatica, gout, calcium pyrophosphate deposition disease (CPPD), and Sjögren’s syndrome. ^5-10 Furthermore, the American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR) have produced evidence and expert opinion-based recommendations on the use of US in the clinical management of rheumatic diseases. ^10-12 This article highlights the most common applications of US for assessment and management of different rheumatic diseases frequently encountered at the VAMC rheumatology inpatient and outpatient clinical service.

Evaluation of Inflammatory Arthritis

In RA and any other inflammatory arthritis, US has been used for the detection of joint effusions, synovitis, bone erosions, and tendon and enthesis involvement. ^11,12 Ultrasound B-mode and power Doppler (PD) techniques have demonstrated a consistent and relevant role in optimizing the diagnosis, assessing the inflammatory activity, monitoring response to therapy, and predicting the inflammatory arthritis outcomes (Figures 1-3). ^10-12 Ultrasound provides real-time information about the status of the synovial membrane, tendons, cartilage, bursae, and cortical bones, allowing an accurate assessment of the degree of inflammatory process in periarticular and articular tissues. Also, US can provide details about the characteristics of the collected fluid (ie, effusion or synovial hypertrophy), which is fundamental for the correct interpretation of the pathologic joint and/or soft tissue processes. The inflammatory process can be assessed by using PD mode, which detects and quantifies the vascular changes in the pannus due to vasodilation and the increased blood flow characteristic of active inflammation. ^13,14

The Outcomes Measures in Rheumatoid Arthritis Clinical Trials (OMERACT) study group developed standardized sonopathologic definitions and scanning methods to be used in the daily rheumatologic practice and clinical trials (Table 1). ¹⁵ Furthermore, it developed a semiquantitative scale to assess the degree of synovitis in US B-mode and PD mode (Table 2). ¹⁵