Indirect MRA has More Diagnostic Value than Conventional MRI in Partial and Subscapularis Tears of Rotator Cuff

Background and purpose: Determining the severity and site of rotator cuff tear (RCT) is very important for choosing a treatment method. In this study, the diagnostic value of indirect magnetic resonance arthrography (I-MRA) and magnetic resonance imaging (MRI) were compared. Materials and methods: This cross-sectional study was performed in 36 patients attending an orthopedic clinic in 2020. Patients with clinical suspicion of RCT were initially treated conservatively for six weeks. If there was no response, first, imaging was performed by MRI and I-MRA and then the patients underwent arthroscopy for final diagnosis and treatment. The images were then evaluated one week apart by a musculoskeletal radiologist. Results: The results of both imaging methods were in line with the arthroscopic results and the amount of I-MRA agreement (k= 0.104 ± 0.698) was higher than MRI (k= 0.115 ± 0.606). Sensitivity, specificity, positive predictive value (PPV), negative (NPV), and accuracy of MRI and I-MRA in diagnosing partial RCTs were 78.28, 84.62, 90.00, 68.75, and 80.55 vs. 86.96, 92.3, 95.24, 80.00, 88.89, respectively. In detection of full-thickness RCTs, the sensitivity, specificity, NPV, PPV, and accuracy of the two methods were similar (88.89, 92.59, 80.00, 96.15, and 91.67, respectively). Sensitivity, specificity, NPV, PPV, and accuracy on MRI and I-MRA in diagnosis of subscapularis tears were 50.00, 96.87, 66.67, 93.94, and 91.67 vs. 50.00, 100, 100, 94.14, and 94.44, respectively. Conclusion: I-MRA has more diagnostic value than MRI in detection of partial and subscapularis tears of rotator cuff.