Ryan J. DeWall PhD, Presenter: Nothing to Disclose

Jingfeng Jiang, Abstract Co-Author: Nothing to Disclose

John Wilson MD, MS, Abstract Co-Author: Nothing to Disclose

Kenneth S. Lee MD, Abstract Co-Author: Research Consultant, SuperSonic Imagine Speakers Bureau, Medical Technology Management Institute

Shear wave imaging (SWI) is an US elastography technique that measures tissue elasticity, a tissue property that often correlates with pathology. The purpose of this study was to evaluate the ability of SWI to visualize partial tears and quantify damage in porcine flexor tendons.

Thirty porcine flexor tendons were pre-loaded to 1.25 N and stretched from 0%-2% strain using a Mark-10 (Mark-10 Corp; Copiague, NY) testing system while being imaged using SWI (Aixplorer®; Supersonic Imagine; Aix-en-Provence, France). After imaging the normal tendon, the deep portion was cut to 25% (n = 10), 50% (n = 10), and 75% (n = 10) of the tendon thickness and reassessed with SWI. The deep-to-superficial wave speed ratio of the deep third (cut) and superficial third (uncut) of the tendon were compared in regions-of-interest (ROIs) centered on (C), proximal to (P), and distal to (D) to the tear, excluding the area within the tear. Tukey multiple comparisons were used to assess differences between normal and torn tendons.

Shear wave speed (i.e. elasticity) increased significantly with increasing tissue strain in normal and cut tendons, except in the deep third of the 75% tear (0%, 6.7 ± 1.2 m/s; 2%, 7.7 ± 1.4 m/s). The deep-to-superficial wave speed ratio decreased significantly between normal and cut tendons in the 50% tear in ROIs centered on (0%, 0.98 ± 0.06 to 0.91 ± 0.09; 1%, 0.97 ± 0.06 to 0.81 ± 0.09; 2%, 0.99 ± 0.07 to 0.84 ± 0.10) and distal to (1%, 0.95 ± 0.08 to 0.85 ± 0.08) the tear and in the 75% tear proximal to (1%, 1.00 ± 0.07 to 0.82 ± 0.12; 2%, 1.00 ± 0.07 to 0.81 ± 0.16), centered on (0%, 1.03 ± 0.09 to 0.70 ± 0.10; 1%, 0.99 ± 0.06 to 0.60 ± 0.11; 2%, 0.95 ± 0.10 to 0.61 ± 0.13), and distal to (1%, 0.96 ± 0.15 to 0.79 ± 0.14) the tear.

The decrease in deep-to-superficial wave speed ratio in cut tendon relative to normal tendon suggests loading changes in the damaged fibers. SWI demonstrates the potential for assessing tendon damage in partially torn tendons.

SWI has the potential to add quantitative information to validated US outcome measures, providing a powerful tool for future outcomes analysis using US to monitor and assess tendon injuries.

DeWall, R, Jiang, J, Wilson, J, Lee, K, Quantifying Tendon Damage with Ultrasound (US) Shear Wave Elastography Using a Porcine Flexor Tendon Tear Model.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13029026.html