Advanced imaging techniques are increasingly important in the diagnosis and management of rheumatoid arthritis (RA). Musculoskeletal ultrasound (MSUS) and magnetic resonance imaging (MRI) have significantly enhanced the rheumatologist's ability to assess RA disease activity and progression. These imaging modalities provide detailed evaluations of articular/peri-articular inflammation, joint damage, and treatment response, which facilitates the incorporation of more objective assessments in a condition that has historically depended on subjective clinical judgments.

MSUS has gained widespread use in clinical practice due to its ability to detect subclinical changes suggestive of disease activity, such as synovitis, tenosynovitis, and erosions, which may be missed or cannot be detected during physical examination. With no radiation, good accessibility, and lower costs than other imaging modalities, it is no surprise that the use of MSUS in clinical practice has increased dramatically in recent years. Some reports indicate a rise in use by as much as 12,500 % from 2000 to 2009, highlighting the significant impact its integration into clinical practice may have on RA care [1]. Similarly, MRI provides high-resolution images that detect early joint damage (erosions and joint space narrowing), synovitis, tenosynovitis, and bone marrow edema (BME) in RA-affected soft tissues and bone structures. Furthermore, MRI permits a 360° examination of a joint for erosions, synovitis, and BME. While MRI may be less accessible than bedside MSUS, its standardized imaging acquisition and high inter-/intra-reader reliability has allowed for use in centralized scoring systems such as the Rheumatoid Arthritis Magnetic Resonance Imaging Score (RAMRIS), which have been utilized in a multitude of multicenter RA randomized clinical trials. Both modalities are essential, each contributing their unique strengths to support a thorough and effective approach to patient care in RA.

It is critical to recognize that RA is incurable and can cause significant impairment in quality of life and, in some cases, premature death. Fortunately, the advent of biologic therapies and aggressive treat-to-target (T2T) strategies has transformed RA treatment, making remission and low disease activity (LDA) achievable. However, newer therapies are costly and may have potential side effects, necessitating frequent monitoring to ensure treatment and safety goals are met. In this context, imaging has proven to be a valuable tool not only in diagnosis but also in assessing treatment response and identifying when adjustments are needed.

This piece serves as a five-year update to our previous publication on the contemporary role of imaging in RA, emphasizing the continued importance of MSUS and MRI in clinical practice and their expanding utility [2]. The first sections examine the role of MSUS in diagnosing RA, differentiating RA from mimickers, scoring systems and quality control measures, novel longitudinal approaches to disease monitoring, and patient populations that may benefit most from MSUS. Subsequent sections examine the role of MRI in diagnosing pre-clinical and early RA, disease activity monitoring, research and clinical trials, and development of alternative scoring approaches utilizing artificial intelligence. Finally, the role of MSUS and MRI in RA diagnosis and management is summarized, and selected practice points offer key tips for integrating MSUS and MRI into clinical practice.