Correlation of Joint Volume and Passive Range of Motion With Capsulo-Synovial Thickness Measured by Contrast-Enhanced Magnetic Resonance Imaging in Adhesive Capsulitis

Background: No study has investigated the relationship between the findings of contrast-enhanced magnetic resonance imaging (CE-MRI) and the joint volume of the shoulder, which has been considered the standard reference for diagnosis of adhesive capsulitis (AC). Objective: To investigate the relationships among the capsulo-synovial thickness measured by CE-MRI, joint volume, and passive range of motion (ROM) in patients with AC. Design: This was a retrospective study. Setting: The study took place at an institutional practice. Patients: Medical record of 103 patients (46 male and 57 female), who were treated with sonographically guided intra-articular injection with diagnosis of AC and underwent CE-MRI to rule out other concomitant shoulder disease, were retrospectively reviewed. Methods: Passive ROM and glenohumeral joint (GHJ) volume were measured before and during sonographically guided injection. The thickness of the enhancing portion of the capsulo-synovium was measured at the axillary recess and rotator interval on CE-MRI. Main Outcome Measurements: The relationship among the thickness of the enhancing portion on CE-MRI, GHJ volume, and passive ROM was analyzed using the Pearson correlation coefficient. Results: Capsulo-synovial thickness measured by CE-MRI at the enhancing portion of the axillary recess inversely correlated with GHJ volume (ρ = −0.444, P <.001), whereas at the rotator interval, this finding was not observed. At the axillary recess, the capsulo-synovial thickness inversely correlated with abduction (ρ = −0.400, P <.001), forward elevation (ρ = −0.378, P <.001), and external rotation (ρ = −0.297, P <.01), but at the rotator interval, such statistically significant correlations were not shown. Conclusion: The capsulo-synovial thickness measured by CE-MRI at the enhancing portion of the axillary recess could represent obliterated joint capacity and clinical impairment (restricted passive ROM), which could help in diagnosing AC and in differentiating other shoulder diseases that may mimic this condition.