ROLE OF ULTRASOUND IN EARLY DIAGNOSIS OF RHEUMATOID ARTHRITIS- A VALIDATION STUDY

Abstract

Background: Rheumatoid arthritis (RA) is a common autoimmune disorder that can cause irreversible joint damage if not diagnosed and treated early. While clinical criteria and laboratory tests are commonly used for RA diagnosis, imaging techniques like ultrasound (US) have emerged as valuable tools for early detection, offering advantages in terms of sensitivity, specificity, and cost-effectiveness.

Objective: This study aims to validate the role of ultrasound in the early diagnosis of rheumatoid arthritis, using clinical diagnosis as the gold standard.

Methods: A cross-sectional validation study was conducted at Ayub Teaching Hospital, Abbottabad. A

total of 146 patients with clinical suspicion of RA were recruited between December 2024 to November 2025. All participants underwent a clinical assessment based on the 2010 American College of Rheumatology (ACR) and European League Against Rheumatism (EULAR) criteria for RA. Subsequently, ultrasound examinations were performed by an experienced radiologist to assess features indicative of RA, such as synovial hypertrophy and increased blood flow. The diagnostic performance of ultrasound was evaluated in terms of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), using the clinical diagnosis as the reference.

Results: Of the 146 participants, 93 (63.7%) were clinically diagnosed with RA, and 74 (50.7%) had positive ultrasound findings. The most common indicator on ultrasound for RA was synovial fluid presence, seen in 83 (56.8%) followed by synovitis seen in 78 (53.4%). The sensitivity of ultrasound for detecting RA was 83.8%, with a specificity of 56.9%. The PPV was 66.8%, and the NPV was 77.4%. The area under the ROC curve (AUC) was 0.720, indicating a moderate diagnostic accuracy of ultrasound.

Conclusion: Ultrasound demonstrated moderate diagnostic performance in the early detection of rheumatoid arthritis. Its high sensitivity makes it a valuable tool for identifying patients with RA, though its specificity suggests that further refinements or complementary tests may be necessary. Ultrasound offers a promising adjunct to clinical criteria in the early diagnosis of RA, particularly in resource-limited settings where cost and radiation exposure are concerns.