科研之友
微信
新浪微博
Facebook
分享链接
摘要
Increase in bladder stiffness could be associated with various pathophysiologic conditions. Measuring bladder viscoelasticity could be an important step towards understanding various disease processes and improving patient care. Here, we introduce ultrasound bladder vibrometry (UBV), a novel method for rapid and noninvasive measurement of bladder wall viscoelasticity. UBV uses acoustic radiation force to excite mechanical waves in the bladder wall and track the motion using ultrasound pulse-echo techniques. Fourier domain analysis of the tissue motion versus time is used to calculate the phase velocity dispersion (change of phase velocity as a function of frequency). The measured phase velocity dispersion is fit with the antisymmetric Lamb wave model to estimate tissue elasticity and viscosity. We used finite element analysis of viscoelastic plate deformation to investigate the effect of curvature on Lamb wave dispersion and showed that the effects of curvature are negligible. The feasibility of the UBV technique was demonstrated in ex vivo and in vivo settings. Elasticity and viscosity of excised pig at various filling volumes (V) and pressures (p) were found to be mu(1) = 9.6 kPa and mu(2) = 0.2 Pa s (V = 187 ml and p = 8.6 mmHg), mu(1) = 48.7 kPa and mu(2) = 3.5 Pa s (V = 267 ml and p = 17.6 mmHg), and mu(1) = 106.9 kPa and mu(2) = 1.5 Pa s (V = 327 ml and p = 27.6 mmHg) respectively. Transabdominal measurements in an anesthetized pig found values of bladder elasticity mu(1) = 26.1 kPa and viscosity mu(2) = 0.9 Pa s and demonstrate the ability of UBV to perform in vivo measurements. The results presented in this paper introduce a novel technique for measuring mechanical properties of the bladder and lay the foundation for further investigation of the effects of pathology on bladder viscoelasticity.
- 出版日期2013-4-21
