Objective: Evaluating tendon abnormalities can be a difficult task despite recent advances in medical imaging. Ultrasound has well known distinctive advantages over other imaging modalities, but widespread musculoskeletal application has been limited in the United States. Innovative developments in ultrasound technology may expand diagnostic capabilities of musculoskeletal ultrasound and thereby increase its usage. The goal of this pilot study is to validate this new tissue characterization method, acoustoelastography (AE), in the clinical setting.
Method: Our research group has developed an innovative ultrasound wave analysis method termed acoustoelastography, based on a mathematical theory called acoustoelasticity that relates mechanical properties to acoustic characteristics in deformed tissue. Variations of tendon stiffness seen in pathological states can then be calculated. Our pilot study looked at 15 Achilles tendons (5 normal tendons, 4 partial thickness tears, 6 chronic tendinopathy) in 9 patients (7 females and 2 males, age range 36-75; avg. 56.4). Tendon stiffness variations were calculated after conventional diagnostic ultrasound exam was performed by a fellowship-trained musculoskeletal radiologist. Statistical analysis was performed comparing normal versus abnormal tendons, and comparing partial tear versus tendinopathy, using the final diagnosis from the conventional diagnostic ultrasound as the standard.
Results: Statistical analysis comparing normal and abnormal tendons showed that AE achieved 90% sensitivity, 100% specificity, and 93% accuracy. Statistical analysis comparing partial tear versus chronic tendinopathy within the abnormal tendons showed that AE achieved 80% sensitivity, 100% specificity and 90% accuracy.
Conclusion: Acoustoelastography is a new tissue characterization method that has promising clinical potential for diagnostic musculoskeletal ultrasound.