Over the past several years, several new therapies have been developed to help slow the progression of joint destruction in rheumatoid arthritis. Because of these therapeutic advances, it is important to identify patients with rheumatoid arthritis early and to predict which patients will go on to severe disability if not aggressively managed.
Studies have shown that patients without the longstanding disease (>18 months) may not have erosions on conventional X-ray. Benton et al reported that less than 20% of patients with RA of less than 6 months duration showed erosions on X-ray. Baseline MRI showed bone erosions in 42% of the patients with early RA in Benton’s study, whereas radiography detected erosions in only 15% of these patients. Unlike MRI, X-ray cannot detect pre-erosive inflammation or visualize cartilage, synovium, joint effusion and tendons.
MRI is the best imaging modality for RA. It is a powerful tool, and our imaging center can help clinicians detect the early pre-erosive changes well before abnormalities occur on X-ray.
Large bone erosion in the distal pole of the scaphoid is barely visible with radiography.
T2 weighted image shows erosion in metacarpal and lunate (arrows) with only subtle findings on xray. A large amount of synovial fluid within the flexor pollicis longus bursa is present, which cannot be seen on X-ray.
Subcortical erosion (arrow) connecting with inflamed synovium.
References:
Benton, N et al. MRI of the wrist in early rheumatoid arthritis can be used to predict the functional outcome at 6 years. Ann Rheum Dis 2004;63:555-561.
Sommer, O et al. Rheumatoid Arthritis: A Practical Guide to State-of-the-Art Imaging, Image Interpretation and Clinical Implications. RadioGraphics 2005;25:381-389.