Objective: Real-time sonoelastography is a new ultrasound-based technique able to assess tissue elasticity that has already shown feasibility in tumor diagnosis. The aim of this study was to assess the performance of real-time sonoelastography in depicting the Achilles tendons of healthy volunteers and to compare sonoelastography findings with conventional ultrasound findings.
Materials and methods: Eighty asymptomatic Achilles tendons of 40 healthy volunteers (19 men, 21 women; mean age, 38 years; range, 20-76 years) were examined on real-time sonoelastography and ultrasound. The Achilles tendons were divided into the following thirds for image evaluation: proximal (musculotendinous junction), middle (2-6 cm above insertion at the calcaneus), and distal (insertion at the calcaneus). Longitudinal and axial images of each tendon third were obtained using ultrasound and real-time sonoelastography. Real-time sonoelastography images were evaluated by reviewers using an experimentally proven color grading system.
Results: The Achilles tendons showed mainly a hard structured pattern (86.7%) (208/240 tendon thirds) on sonoelastography; however, mild softening was found in 12.1% (29/240) of the tendons. Distinct softening corresponding to alterations found also on ultrasound and, therefore, suggesting subclinical changes was detected in 1.3% (3/240). The overall correlation (kappa) between real-time sonoelastography and ultrasound findings was 1.00.
Conclusion: In healthy volunteers, the Achilles tendon appeared hard on real-time sonoelastography with excellent correlation to ultrasound. Further investigation including pathologic tendons should be performed to prove the value of real-time sonoelastography in the assessment of Achilles tendinopathy.