Magnetic resonance imaging versus ultrasonography for the diagnosis of synovitis in rheumatoid arthritis

Added value of high-resolution ultrasound and MRI in the evaluation of rheumatologic diseases

Rheumatologic diseases are a widespread group of disorders affecting the joints, bones, and connective tissue, and leading to significant disability. Imaging is an indispensable component in diagnosing, assessing, monitoring, and managing these disorders, providing information about the structural and functional alterations occurring within the affected joints and tissues. This review article aims to compare the utility, specific clinical applications, advantages, and limitations of high-resolution ultrasound and magnetic resonance imaging in the context of rheumatologic diseases. It also provides insights into the imaging features of various types of inflammatory arthritis with clinical relevance and a focus on high-resolution ultrasound and magnetic resonance imaging. By understanding the comparative aspects of high-resolution ultrasound and magnetic resonance imaging, it is easier for the treating physicians to make informed decisions when selecting the optimal imaging modality for specific diagnostic purposes, effective treatment planning, and improve patient outcomes. The patterns of soft tissue and joint involvement; bony erosion and synovitis help in differentiating between various type of arthritis. Involvement of various small joints of the hands also gives an insight into the type of arthritis. We also briefly discuss the potential applications of emerging techniques, such as ultrasound elastography, contrast-enhanced ultrasound, and dual-energy CT, in the field of rheumatology.

Imaging of Rheumatological Disorders

Early diagnosis and treatment of many rheumatological conditions has become crucial in order that drug therapies can be started before irreversible structural damage occurs. Both MR imaging and ultrasound play a valid role in the pathway of many of these conditions. The imaging findings as well as relative merits are described in this article as well as limitations that must be kept in mind when interpreting the imaging. Both conventional radiography and computed tomography also add important information in certain cases and should not be forgotten.

3D MRI of the Rheumatic Diseases

Magnetic resonance imaging (MRI) is commonly used to evaluate musculoskeletal pathologies due to its high spatial resolution and excellent tissue contrast. The diagnosis of rheumatic diseases can often be challenging. Investigation with conventional two-dimensional MRI is helpful for diagnosis and monitoring treatment. In the past few years, three-dimensional (3D) MRI has been more commonly used to assess joint pathologies including inflammatory and rheumatic diseases. This review discusses the techniques and protocols of 3D MRI and its diagnostic yield in the assessment of rheumatic diseases, along with different examples.

Quantitative power Doppler signal assessment in the subchondral bone region of the metacarpophalangeal joint is an effective predictor of radiographic progression in the hand of rheumatoid arthritis: a pilot study

Ultrasonography is useful for assessment of synovitis in the hand of rheumatoid arthritis (RA) patients. The aim of this study was to investigate the predictive value of the quantitative power Doppler (PD) signal assessment in the subchondral bone region of the metacarpophalangeal (MCP) joint in patients with RA showing radiographic progression of the hand by comparing with those of previously reported scoring systems. Twenty-two patients (20 women) with RA who underwent power Doppler ultrasonography (PDUS) of the bilateral one to five MCP joints at baseline were included in the study. Radiography of both hands was performed at baseline and at 1 year. PDUS of the synovial space was evaluated according to semi-quantitative scoring (0-3) and quantitative measurement (0-100%). The PD signal in the subchondral bone region was qualitatively (0, 1) and quantitatively (mm²) assessed. The performance of PDUS assessment was compared using the area under the curve (AUC) of the receiver operating characteristic (ROC) curve and the risk ratio (RR). As a predictor for radiographic progression, the quantitative PD signal assessment in the subchondral bone region (AUC = 0.842, p < 0.01) was equivalent to quantitative vascularity (AUC = 0.817, p < 0.05) and semi-quantitative scoring (AUC = 0.754, p < 0.05). As for the RR of the PD signal in the subchondral bone region for radiographic progression, the quantitative PD signal assessment was 5.40 (p < 0.01), whereas the qualitative PD signal assessment was 1.60 (p = 0.204). Quantitative PD signal assessment in the subchondral bone region can predict radiographic progression in the hand of RA patients.