Purpose
We studied the relation between the morphological findings of the supraspinatus muscle on MRI and its elongation length in order to evaluate the elasticity of the atrophic supraspinatus muscle in a patient with a cuff tear.
Materials and Methods
Twenty shoulders with cuff tears were scanned in the oblique coronal plane on T1 and T2* weighted sequences with a 0.5T unit. We calculated the ratio of the longest width of the supraspinatus muscle belly to the distance from the greater tuberosity to the proximal end of the supraspinatus muscle, which was termed“Supraspinatus Muscle Belly Ratio”and abbreviated it as “SMBR”. We classified the appearance of a linear band and the degree of the retracted tendon fiber in the supraspinatus muscle into three grades. Thus we compared the elongation length of the supraspinatus muscle at surgery with the length of cuff defect, “SMBR” and their morphological grades.
Results
The elongation length had a negative correlation with the degree of retracted tendon fiber but no correlation with the length of cuff defect, SMBR and appearance of linear band.
Conclusion
We could evaluate the elasticity of the supraspinatus muscle in patients with a cuff tear by analyzing the degree of retracted tendon fiber on MRI.
