Shear wave elastography imaging in a porcine tendinopathy model

• Published in: Skeletal radiology 2022-11, Vol.51 (11), p.2167-2173
• Main Authors: Quilling, Grant M., Lee, Kenneth S., Ebben, Beau
• Format: Article
• Language: English
• Subjects: Biomechanics; Collagen; Collagenase; Elasticity; Imaging; Injection; Injuries; Medicine; Medicine & Public Health; Microscopy; Nuclear Medicine; Orthopedics; Pathology; Radiology; Scientific Article; Statistical analysis; Strain; Structural damage; Tendons; Ultrasonic imaging; Ultrasonic scanners
• ISSN: 0364-2348; 1432-2161
• DOI: 10.1007/s00256-022-04073-x

Objective To quantify the effect of structural damage in an ex vivo animal tendinopathy model using shear wave elastography (SWE). Materials and methods Sixteen porcine flexor tendons were injected with a 0.05 mL bolus of 1.5% collagenase solution to induce focal structural damage without surfacing tears. Control tendons were injected with saline ( n  = 16). Eight tendons from each group were incubated at 37 °C for 3.5 h while the remaining 8 from each group were incubated for 7 h. Tendons were mechanically stretched to 0% and 1% strain. Simultaneously, SWE was acquired proximal to, at, and distal to the injection site using a clinical ultrasound scanner. Results There were significant differences in SWS (saline > collagenase) at 1% strain and 7-h incubation for all three locations (PROX p  = 0.0031, ROI p  = 0.001, DIST p  = 0.0043). There were also significant differences at 0% strain and 7 h, but only at ( p  = 0.0005), and distal to (p = 0.0035), the injection site. No statistically significant differences were observed for 3.5-h incubation, at 0% or 1% strain. Conclusions Collagenase-mediated structural damage does appear to convey decreased tissue elasticity on SWE when ex vivo tendons are incubated for 7 h. These findings suggest that SWE may be a useful tool for predicting ultimate tissue strength in tendinopathic tissues. Pull-to-failure testing should be performed in the future and are expected to show that tendons with decreased SWS, and, therefore, decreased elasticity, rupture at lower pulls forces.