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Abstract

Background: Rheumatoid arthritis (RA) is a chronic autoimmune disorder that primarily affects the distal joints, leading to progressive synovial inflammation, structural damage, and functional impairment if untreated. Imaging plays a pivotal role in early detection and disease monitoring. Although magnetic resonance imaging (MRI) is the gold standard for identifying early joint pathology, its limited availability and high cost restrict routine use. Therefore, the diagnostic accuracy of ultrasound (US) and conventional radiography (CR) must be established to optimize early RA assessment in resource-constrained settings.
Objective: To determine the diagnostic accuracy of ultrasound and conventional radiography in detecting early rheumatoid arthritis in the small joints of the hands, using MRI as the reference standard.
Methods: A cross-sectional analytical study was conducted over nine months at Kot Khwaja Saeed Hospital, Lahore, after ethical approval. A total of 47 clinically suspected RA patients aged 18–60 years were enrolled through convenient sampling. All underwent CR, high-frequency US, and MRI imaging of hand joints. Standardized scoring systems—OMERACT-EULAR for US, Sharp/van der Heijde for CR, and RAMRIS for MRI—were applied to assess synovitis, bone erosions, and joint space narrowing. MRI served as the gold standard for calculating sensitivity, specificity, predictive values, and diagnostic accuracy.
Results: Among the 47 participants, 68.1% were female, and the mean age was 37.2 ± 12.1 years. Joint pain, swelling, and stiffness were reported in 89.4%, 76.6%, and 70.2% of cases, respectively. RA was detected in 83.0% of patients by MRI, 93.6% by US, and none by CR. Ultrasound demonstrated a sensitivity of 94.8%, specificity of 62.5%, positive predictive value of 81.8%, and diagnostic accuracy of 61.7%. Conventional radiography showed poor sensitivity (0%) but perfect specificity (100%) for early erosive changes.
Conclusion: Ultrasound proved to be a highly sensitive, non-invasive, and cost-effective imaging modality for early detection of rheumatoid arthritis, outperforming conventional radiography in identifying synovitis and bone erosions. Although MRI remains the most precise technique, integrating ultrasound into early rheumatologic evaluation can significantly enhance timely diagnosis and disease management.