Ultrasound and Shear Wave Elastography for Assessment of the Quality of Rotator Cuff Muscles

Rotator cuff disorders are among the most frequent musculoskeletal causes of shoulder pain, weakness, and limited movement. In many individuals with rotator cuff disease, the damaged muscles gradually shrink (muscle atrophy) and become replaced by fat tissue (fatty infiltration), particularly involving the supraspinatus and infraspinatus muscles. These structural changes can impair shoulder function, reduce the likelihood of successful tendon repair surgery, and increase the risk of recurrent tears.

Magnetic resonance imaging (MRI) is the established standard for assessing rotator cuff muscle health, but it is expensive, time-consuming, and not suitable for all individuals. Musculoskeletal ultrasound offers an accessible, real-time alternative, and shear wave elastography (SWE) adds the capability to quantitatively measure tissue stiffness.

The purpose of this study is to evaluate the diagnostic accuracy and validity of combining conventional ultrasound with shear wave elastography to assess rotator cuff muscle quality, specifically fatty infiltration and muscle atrophy, in comparison with reference MRI or CT scans.

Participants aged 18 years or older with suspected rotator cuff disorders who have had a qualifying shoulder MRI or CT scan within the previous 12 months will undergo an ultrasound and shear wave elastography examination of the affected shoulder. Researchers will calculate shear wave velocity and muscle occupation ratios to assess muscle stiffness and volume, and compare these results to validated MRI grading scales (the Goutallier classification for fat infiltration and the Warner staging system for muscle atrophy).