Radiographic diagnosis of rotator cuff tear based on the supraspinatus muscle radiodensity

Objective. To evaluate the supraspinatus muscle radiodensity on the outlet view as an indication of a tendon tear. Design and patients. Plain radiographs and magnetic resonance imaging (MRI) examinations were obtained on both shoulders of 40 subjects aged 23-70 yea rs, including 13 asymptomatic volunteers and 27 patients. Two readers analy zed the superior contour and the heterogeneity of the supraspinatus muscle radiodensity and compared them with the MRI findings. Results and conclusion. Significant concordances (P<0.001) were found betwe en the assessments of the superior contour and the heterogeneity of the mus cle radiodensity, respectively, on plain radiographs and MR images. For the diagnosis of a full-thickness tear, the analysis of the superior contour a nd the heterogeneity of the muscle radiodensity reached an accuracy of 85% and 80% respectively. Stepwise discriminant analyses showed low to moderate benefit of considering the contour and the heterogeneity simultaneously. T he inter- and intraobserver agreement ranged from moderate to good. We conc lude that on the outlet view, modifications in the superior contour and het erogeneity of the supraspinatus muscle radiodensity suggest a full-thicknes s tear.