Abstract:
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Purpose: Fatty atrophy of the rotator cuff muscle after a tendon tear is associated with an unfavorable clinical outcome after surgical reconstruction. The purpose of the study was to evaluate the accuracy of ultrasound in the diagnosis of fatty atrophy of supraspinatus and infraspinatus muscles.
Methods and Materials: Supraspinatus (SSP) and infraspinatus (ISP) muscles of 65 consecutive patients with suspected rotator cuff tears were evaluated with ultrasound in two planes. Visibility of muscle contour, pennation, central tendon and muscle echogenicity were assessed (three grade scale) by two radiologists on a PACS workstation. Accuracy, sensitivity, specificity, over-, underestimation and inter-observer rates for the diagnosis of substantial atrophy (Goutallier grade 2-4) were evaluated. MRI was used as standard of reference.
Results: Eleven patients had normal SSP or ISP tendons, 12 had partial and 42 full-thickness tears. Twenty patients had substantial muscle atrophy. Accuracy of ultrasound was 80% for reader 1 and 76% for reader 2, sensitivity was 68%/75%, specificity was 83%/76%. Overestimation of muscle atrophy was higher (reader 1: 13%, reader 2: 18%) than underestimation (7%,/ 5%). Inter-observer rate was good (k= 0.63).
Conclusion: Ultrasound has a moderate accuracy for the diagnosis of substantial SSP or ISP fatty muscle atrophy with tendency to overestimate the grade of atrophy. Although MRI remains the standard of reference for assessment of SSP and ISP fatty muscle atrophy in patients with rotator cuff tear, information about such atrophy should be also given when ultrasound is performed.
Strobel MD, K,
Accuracy of Ultrasound in Diagnosis of Fatty Atrophy of Supraspinatus and Infraspinatus Muscles. Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL.
http://archive.rsna.org/2003/3106518.html
