MR imaging biomarkers for evaluation of adhesive capsulitis of the shoulder. Additive value of anterior capsule abnormality as a reliable criterion for diagnosis of adhesive capsulitis: a cross sectional analytic study

Background Adhesive capsulitis of the shoulder is a pain syndrome of progressive nature, associated with reduced active and passive range of motion of the gleno-humeral joint. Previous studies suggested an underlying synovial inflammatory process, followed by capsular hypertrophy and reactive fibrosis. The aim of our study was to investigate the influence of anterior shoulder joint capsule abnormal thickening and abnormal signal intensity on MRI, as important imaging biomarkers, for the diagnosis of as adhesive capsulitis. Results This cross sectional analytic study involved 28 patients with adhesive capsulitis ((17 males, 11 females, age range:23–65 years, mean age: 45.61 years ± 11.95) and 28 controls (14 males, 14 females; age range, 39 to 61 years; mean age 52.82 years ± 6.45;). The patients and the controls were reviewed by two radiologists with experience of more than 10 years, blinded to each other's results. Adhesive capsulitis was diagnosed based on clinical criteria of significant restricted passive motion of shoulder joint. The thickness and abnormal signal intensity of anterior glenohumeral joint capsule were evaluated at its thickest portion, positioned underneath the subscapularis muscle. Additionally, the formerly known MR characteristics of adhesive capsulitis, involving the thickness of humeral and glenoid portions of axillary recess, maximal thickness of axillary capsule, and thickness of coracohumeral ligament, were assessed. The estimation of abnormal hyperintensity of humeral and glenoid capsule in axillary recess, subcoracoid fat triangle obliteration and abnormal hyperintensity were also included in our study. All magnetic resonance imaging (MRI) quantitative values showed significant difference between adhesive capsulitis group and control group. Regarding qualitative values, only abnormal high signal intensity of the anterior portion of joint capsule, of the axillary portion of joint capsule and of glenoid portion of axillary capsule showed statisticaly significant difference between cases and controls. In receiver operating characteristic (ROC) curve study, the anterior capsule thickness revealed a high diagnostic value with an area under the curve (AUC) of 1.0. An anterior capsule thickness cut off value of at 2.45 mm showed a very high diagnostic performance, revealing a sensitivity of and specificity of 100%. Conclusions The anterior glenohumeral joint capsule abnormal thickening, and abnormal hyperintensity have a high diagnostic performance, in addition to the previously known abnormal MRI findings, in the evaluation of adhesive capsulitis.