Diagnosis of small partial-thickness rotator cuff tears using vibro-acoustography

Purpose: Vibro-acoustography is a new imaging technique based on the dynamic radiation force of ultrasound. The purpose of this study was to apply this new imaging technique to the diagnosis of small partial-thickness rotator cuff tears and to determine how small of tears could be detected with this imaging technique.

Methods: Seven supraspinatus tendons excised from embalmed cadavers were used. Three different sizes of partial-thickness bursal-sided tears (1, 3, and 5 mm³) were created in each specimen. The intersection of two co-focused ultrasound beams of slightly different frequency was swept across the intended imaging area. The acoustic emission data were collected and used to form and display a vibro-acoustography image of the tendon. Vibro-acoustography images were read by two orthopedic surgeons.

Results: The rotator cuff tear could be detected by vibro-acoustography in all specimens. The diagnostic concordance rate was 90.5 % and the kappa coefficient value was 0.88, which resulted in a high concordance. The diagnostic concordance rate for the 1 mm tear was 71.3 %, which was low concordance (κ = 0.481), whereas that for the 3 and 5 mm tears was 100 %.

Conclusions: We were able to detect a 3-mm tear by using vibro-acoustography. There is a possibility that this new imaging technique could become a useful imaging tool for the diagnosis of small partial-thickness rotator cuff tears.