Effect of temperature on the measurement of soft tissue viscoelasticity with Shearwave Dispersion Ultrasound Vibrometry

Abstract

As an application of ultrasound in medical diagnostic ultrasound elasticity imaging is used to observe changes in tissue elasticity associated lesions or tumors detected within the tissue In these technologies Shearwave Dispersion Ultrasound Vibrometry (SDUV) provides a quantitative measurement for tissue viscoelasticity In order to evaluate the sensitivity of SDUV method on detecting viscoelastic differences in the organization and to explore the effects of temperature effect on tissue viscoelasticity this study using a mechanical vibrator to generate shear wave and verify its feasibility in phantom experiments followed by two-layer phantom experiments with gelatin concentrations of 3% and 9% to test the identifying ability of SDUV method Finally the viscoelasticity of in vitro porcine liver was measured between 25-40 degrees Shear waves with frequency of 50 to 300 Hz were detected by a 30 MHz ultrasound transducer The verification results prove that the use of mechanical vibrator can produce shear waves with amplitude of about 50 μm helps to reduce measurement error; two-layer phantom experiments confirmed SDUV method can distinguish differences in tissue viscoelasticity within 5 mm; in vitro results show that the viscoelasticity of porcine liver linearly changed from μ1 =3 635±0 25 kPa and μ2 =2 016±0 21 Pa‧s down to μ1=2 016±0 21 kPa and μ2=0 93±0 18 Pa‧s while heating In conclusion this study confirms the potential of SDUV method to diagnose viscoelasticity differences within the tissue; furthermore the viscoelastic properties of the soft tissue changes due to temperature effect

Date of Award	2014 Aug 24
Original language	English
Supervisor	Shyh-Hau Wang (Supervisor)