Elastography (SWE) of the Supraspinatus Muscle and Rotator Cuff in Shoulder Tendinopathy: Capabilities and Limitations of the Method
The Role of Elastography in Tendon Assessment
According to sources, elastography in musculoskeletal examination is based on assessing tissue stiffness. In compression (strain) elastography, normal tendons are colored blue, while tendinopathy areas—such as the Achilles tendon or common extensor tendon of the elbow—are colored red. In shear wave and transient elastography, shear wave speed is measured to determine elasticity; the advantage of the method is less operator dependence and the ability to obtain both qualitative and quantitative information.
SWE as an Adjunct Method
According to sources, SWE is less operator-dependent than strain elastography and allows for both qualitative and quantitative assessment. However, elastography is considered an adjunct method to standard ultrasound and does not have sufficient specificity to be used independently for characterizing soft tissue lesions. Elastography is most useful in three areas: carpal tunnel syndrome, Achilles tendinopathy, and plantar fasciitis. Specific threshold values for the supraspinatus tendon and rotator cuff stiffness in fragments are not provided [clarify].
Basic Grayscale Assessment of the Cuff
Assessment of the supraspinatus tendon begins in the long axis, as this view shows the three surfaces of the rotator cuff (articular, bursal, and greater tuberosity surfaces) and characteristic bone contours, which are important for accurate classification of tears. Tendon tears appear as anechoic or hypoechoic defects; acute tears are more often anechoic due to fluid. Large tears of the supraspinatus tendon result in tendon retraction and loss of tissue volume with flattening of the normal superior convex shape.
Technical Aspects of Scanning
| Structure | Position / Technique |
|---|---|
| Supraspinatus tendon | Start in the long axis; look for tears, especially at the anterior edge; bursal fluid is a sensitive indirect sign of a bursal surface tear |
| Subscapularis tendon | External rotation of the shoulder aligns fibers perpendicular to the beam, eliminating anisotropy; transducer movement over the lesser tuberosity |
It is noted that subclinical tendinosis and tears are common, so the contralateral shoulder should not be relied upon as an internal reference.
Limitations
According to sources, ultrasonography and MRI have comparable accuracy in detecting and measuring rotator cuff tears (a meta-analysis of 65 articles showed comparable sensitivity and specificity). Elastography remains an adjunct, not a standalone method for characterization. Quantitative SWE thresholds for differentiating normal and tendinopathy of the supraspinatus tendon in fragments are absent [clarify].
Frequently asked questions
Can SWE be used as a standalone method for diagnosing cuff tendinopathy?
No. According to sources, elastography is an adjunct method to standard ultrasound and does not have sufficient specificity for standalone use.
What is the advantage of SWE over compression elastography?
SWE is less operator-dependent and provides both qualitative and quantitative information by measuring shear wave speed.
What threshold values of supraspinatus tendon stiffness should be applied?
Specific quantitative SWE thresholds for the supraspinatus tendon and rotator cuff in fragments are not provided [clarify].
How does a tendinopathy area appear in color (strain) elastography?
Normal tendons are colored blue, while tendinopathy areas are colored red (based on data for the Achilles tendon and common extensor tendon of the elbow).
Is the accuracy of ultrasound and MRI comparable for cuff tears?
Yes, according to a meta-analysis of 65 articles, ultrasonography and MRI are comparable in sensitivity and specificity for diagnosing rotator cuff tears.