Assessment of the rotator cable in various rotator cuff conditions using indirect MR arthrography

Background: The rotator cable is an important structure providing stress shield to the rotator cuff, similar to the mechanism of suspension bridge. Purpose: To evaluate the visibility and appearance of the rotator cable in various conditions of the rotator cuff, using indirect magnetic resonance (MR) arthrography. Material and Methods: Indirect MR arthrography images from 27 patients (age range, 20-63 years) with normal rotator cuffs, and 47 (age range, 20-73 years) with tendinosis, 32 (age range, 49-71 years) with partial-thickness tears, and 55 (age range, 44-75 years) with full-thickness tears in the supraspinatus and infraspinatus tendons (SST-ISTs) were included in this study. In these various rotator cuff conditions, the visibility and appearance (thickness and width) of the rotator cable and the relationships between the rotator cable appearance, rotator cuff tear size, rotator cuff thickness, and patient's age were assessed. Results: On the sagittal MR images, all rotator cables were visible in the normal rotator cuffs and tendinosis/partial-thickness tears of SST-ISTs. In the order of normal cuff, tendinosis, partial-thickness tear, and full-thickness tear of SST-ISTs, the rotator cable tended to become thicker (1.07, 1.27, 1.32, and 1.59 mm, respectively) and narrower (12.1, 10.68, 10.90, and 8.55 mm, respectively). The thickness of the rotator cable was significantly positively correlated with the rotator cuff thickness in the normal rotator cuffs (coefficient, 0.49; P = 0.010) and tendinosis of SST-ISTs (coefficient, 0.53; P < 0.001), but was not correlated with patients' age. Conclusion: On sagittal plane of indirect MR arthrography, most rotator cables were visible. The appearance of the rotator cable changed according to the rotator cuff condition.