Role of Ultrasound in Evaluation of Shoulder Injuries: A Comparative Study of Ultrasound and MRI

Abstract

Introduction: The rotator cuff disorders constitute the most common cause of painful shoulder. Ultrasonography and MRI are widely used in evaluating various shoulder pathologies. USG of shoulder is simple, cheap, fast and non-invasive imaging technology for detection of rotator cuff and non- rotator cuff abnormalities. In this study we have assessed the usefulness of USG in diagnosing the shoulder pathologies and have compared with the MRI. Aim: Evaluation of a patient with painful shoulder with ultrasonography as the initial line of imaging technique as compared to MRI, assessing the accuracy of ultrasonography in diagnosing shoulder joint pathologies, especially rotator cuff abnormalities, using MRI as a reference standard and correlating findings wherever possible, and to delineate pitfalls during image interpretation and limitations of USG. Materials and Methods: Sixty patients were studied prospectively over a period of two years. Study subjects included both men and women in all age groups with shoulder pain, suspected to have musculo-tendinous origin. All patients underwent USG evaluation of the shoulder joint followed by MRI of the affected shoulder. Results: USG showed an accuracy of 70%, 95% and 98% in detection of any tear of supraspinatus, subscapularis and infraspinatus tendon respectively using MRI as reference. USG showed a sensitivity of 88.89%, specificity of 100%, PPV of 100% and NPV of 98.07% in diagnosing full thickness tear of rotator cuff using MRI as reference. For partial thickness tears, it showed a sensitivity of 78.04%, specificity of 89.47%, PPV of 94.11% and NPV of 65.38%. Overall accuracy of USG in detection of any tear of rotator cuff with MRI as reference was 82%. The strength of agreement between USG and MRI for the diagnosis of any tear of rotator cuff is considered to be ‘substantial’ in our study (Kappa=0.635). Conclusion: USG showed comparable results to MRI in assessment of rotator cuff abnormality and should be used as first line of investigation in patients presenting with shoulder pain. It proved to have high sensitivity and specificity for full thickness tears with relatively less sensitivity and specificity in detection of partial thickness tear.

Keywords

• complete tears
• joint effusion
• partial tears
• rotator cuff
• tendinosis