To investigate the accuracy of 3.0 T MR in the diagnosis of full thickness tear and partial thickness tear of the supraspinatus-infraspinatus tendon, and to analyze the causes of missed diagnosis and misdiagnosis of the supraspinatus-infraspinatus tendon tear.

The MRI diagnosis report and arthroscopic surgery records of 210 patients with shoulder joint injuries in Peking University Third Hospital were analyzed retrospectively. Taking the results of arthroscopic surgery as the gold standard, the diagnostic accuracy, sensitivity, specificity, positive predictive value and negative predictive values of 3.0 T MR for full thickness tear and partial thickness tear of the supraspinatus-infraspinatus tendon were calculated, and the reasons of missed diagnosis and misdiagnosis were analyzed.

In 210 patients with rotator cuff injury, the diagnostic accuracy, sensitivity, specificity, positive predictive value and negative predictive value of MRI for full thickness tear of the supraspinatus-infraspinatus tendon were 81.4% (171/210), 83.1% (98/118), 79.3% (73/92), 83.7% (98/117) and 78.4% (73/93) respectively. The diagnostic accuracy, sensitivity, specificity, positive predictive value and negative predictive value of MRI for partial tears of the supraspinatus-infraspinatus tendons were 77.6% (163/210), 65.7% (44/67), 83.2% (119/143), 64.7% (44/68) and 83.8% (119/142) respectively. Among the 44 cases of missed diagnosis and misdiagnosis of the supraspinatus-infraspinatus tendon tear, 21 cases (47.7%) occurred in the junction supraspinatus and infraspinatus tendon-osseous (stop). Among the 7 cases of intra-tendon tear of supraspinatus and infraspinatus muscle, 6 cases were misdiagnosed cases, which was the most easily missed diagnosed type of partial tear. The reason for missed diagnosis was that the signal of partial tear was not high (no fluid signal was shown on T₂WI). Complex laceration was also a type of missed diagnosis in partial tears. Among the 4 cases of superior and inferior surface tendons combined with intra-tendon lacerations, 3 cases were missed diagnosed.

3.0 T MR has higher accuracy for the diagnosis of full thickness tear and partial thickness tear of supraspinatus-infraspinatus tendon, but there is still a certain rate of misdiagnosis and missed diagnosis. A full understanding of the causes of misdiagnosis and missed diagnosis of MR in the diagnosis of rotator cuff tears of supraspinatus and infraspinatus tendons is helpful to further improve the accuracy of MR in the diagnosis of supraspinatus and infraspinatus tendon injuries of shoulder joint.

Magnetic resonance imaging; Supraspinatus-infraspinatus tendons tear; Misdiagnosis and missed diagnosis