title: The use of 2D ultrasound elastography for measuring tendon motion and strain.
abstract: The goal of the current study was to investigate the fidelity of a 2D ultrasound elastography method for the measurement of tendon motion and strain. Ultrasound phantoms and ex vivo porcine flexor tendons were cyclically stretched to 4% strain while cine ultrasound radiofrequency (RF) data and video data were simultaneously collected. 2D ultrasound elastography was used to estimate tissue motion and strain from RF data, and surface tissue motion and strain were separately estimated using digital image correlation (DIC). There were strong correlations (R(2)>0.97) between DIC and RF measurements of phantom displacement and strain, and good agreement in estimates of peak phantom strain (DIC: 3.5±0.2%; RF: 3.7±0.1%). For tendon, elastographic estimates of displacement profiles also correlated well with DIC measurements (R(2)>0.92), and exhibited similar estimated peak tendon strain (DIC: 2.6±1.4%; RF: 2.2±1.3%). Elastographic tracking with B-Mode images tended to under-predict peak strain for both the phantom and tendon. This study demonstrates the capacity to use quantitative elastographic techniques to measure tendon displacement and strain within an ultrasound image window. The approach may be extendible to in vivo use on humans, which would allow for the non-invasive analysis of tendon deformation in both normal and pathological states.
authors.affiliation: Department of Biomedical Engineering, 1513 University Ave, University of Wisconsin-Madison, WI 53705, USA. Electronic address: laura.a.slane@gmail.com.
authors.forename: Laura
authors.initials: L
authors.lastname: Chernak Slane
authors.affiliation: Department of Biomedical Engineering, 1513 University Ave, University of Wisconsin-Madison, WI 53705, USA; Department of Mechanical Engineering, University of Wisconsin-Madison, WI, USA; Department of Orthopedics and Rehabilitation, University of Wisconsin-Madison, WI, USA.
authors.forename: Darryl G
authors.initials: DG
authors.lastname: Thelen
mesh_terms: D000818:Animals; D054459:Elasticity Imaging Techniques / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D008954:Models, Biological; D009038:Motion; D019047:Phantoms, Imaging; D013314:Stress, Mechanical; D013552:Swine; D013708:Tendon Injuries / Q000000981:diagnostic imaging* / Q000503:physiopathology; D013710:Tendons / Q000000981:diagnostic imaging* / Q000502:physiology; D014159:Transducers; D016474:Weight-Bearing / Q000502:physiology
keywords: Tendon mechanics; Ultrasound elastography