Role of Ultrasonography and Magnetic Resonance Imaging in Diagnosing Shoulder Pathologies: A Prospective Observational Study

Background Shoulder pain is a common musculoskeletal complaint with diverse etiologies involving rotator cuff, labral, and periarticular structures. Accurate imaging is essential for diagnosis and management. Ultrasonography (USG) and magnetic resonance imaging (MRI) are widely used modalities, each with distinct advantages and limitations. The aim of this study was to compare the diagnostic performance of USG and MRI in evaluating shoulder pathologies, particularly rotator cuff tears, using surgical or arthroscopic findings as the reference standard where available, and to assess their complementary roles in clinical practice. Methods This prospective observational study included 75 patients presenting with shoulder pain, restriction of movement, or instability. All patients underwent USG and MRI of the affected shoulder using standardized protocols. USG and MRI examinations were interpreted independently by experienced musculoskeletal radiologists. Readers were blinded to the findings of the other imaging modality at the time of reporting; however, relevant clinical history regarding the symptomatic side was available, consistent with routine diagnostic practice. Radiologists were not blinded to surgical outcomes at the time of final correlation, as surgical findings were used as the reference standard in the operative subgroup. Imaging findings were compared between modalities and correlated with surgical or arthroscopic findings where available. Diagnostic performance parameters, including sensitivity and specificity, were calculated in the surgically verified subgroup (n=34). Interobserver agreement for USG and MRI interpretations was not formally assessed. Statistical analysis was performed using the chi-square test, with p<0.05 considered statistically significant. Results The study population showed a male predominance (52/75; 69.3%) and greater involvement of the right shoulder (54/75; 72.0%). Trauma was the most common etiological factor, observed in 44/75 patients (58.7%). Bursitis or joint effusion (32/75; 42.7%) and rotator cuff tears (29/75; 38.7%) were the most frequently detected pathologies. MRI demonstrated higher sensitivity than USG for detecting overall rotator cuff tears (96.5% vs. 87.0% sensitivity) and full-thickness rotator cuff tears (100% vs. 88.0% sensitivity). MRI also showed higher specificity for rotator cuff tear detection (90.0% vs. 82.0%). Additionally, MRI was superior in detecting labral and instability-related lesions. However, the difference in diagnostic performance between USG and MRI was not statistically significant (χ²=17.07, p=0.105). Conclusion USG is a reliable first-line imaging modality for evaluating common shoulder pathologies, while MRI provides superior characterization of complex soft-tissue and intra-articular lesions. A combined imaging approach optimizes diagnostic accuracy and clinical decision-making.