TY - JOUR
T1 - Application of Acoustoelasticity to Evaluate Nonlinear Modulus in Ex Vivo Kidneys
AU - Aristizabal, Sara
AU - Amador Carrascal, Carolina
AU - Nenadic, Ivan Z.
AU - Greenleaf, James F.
AU - Urban, Matthew W.
N1 - Publisher Copyright:
© 1986-2012 IEEE.
PY - 2018/2
Y1 - 2018/2
N2 - Currently, dynamic elastography techniques estimate the linear elastic shear modulus of different body tissues. New methods that investigate other properties of soft tissues such as anisotropy, viscosity, and shear nonlinearity would provide more information about the structure and function of the tissue and might provide a better contrast than tissue stiffness and hence provide more effective diagnostic tools for some diseases. It has previously been shown that shear wave velocity in a medium changes due to an applied stress, a phenomenon called acoustoelasticity (AE). Applying a stress to compress a medium while measuring the shear wave velocity versus strain provides data with which the third-order nonlinear shear modulus A can be estimated. To evaluate the feasibility of estimating A, we evaluated ten ex vivo porcine kidneys embedded in 10% porcine gelatin to mimic the case of a transplanted kidney. Under assumptions of an elastic incompressible medium for AE measurements, the shear modulus was quantified at each compression level and the applied strain was assessed by measuring the change in the thickness of the kidney cortex. Finally, A was calculated by applying the AE theory. Our results demonstrated that it is possible to estimate a nonlinear shear modulus by monitoring the changes in strain and μ due to kidney deformation. The magnitudes of A are higher when the compression is performed progressively and when using a plate attached to the transducer. Nevertheless, the values obtained for A are similar to those previously reported in the literature for breast tissue.
AB - Currently, dynamic elastography techniques estimate the linear elastic shear modulus of different body tissues. New methods that investigate other properties of soft tissues such as anisotropy, viscosity, and shear nonlinearity would provide more information about the structure and function of the tissue and might provide a better contrast than tissue stiffness and hence provide more effective diagnostic tools for some diseases. It has previously been shown that shear wave velocity in a medium changes due to an applied stress, a phenomenon called acoustoelasticity (AE). Applying a stress to compress a medium while measuring the shear wave velocity versus strain provides data with which the third-order nonlinear shear modulus A can be estimated. To evaluate the feasibility of estimating A, we evaluated ten ex vivo porcine kidneys embedded in 10% porcine gelatin to mimic the case of a transplanted kidney. Under assumptions of an elastic incompressible medium for AE measurements, the shear modulus was quantified at each compression level and the applied strain was assessed by measuring the change in the thickness of the kidney cortex. Finally, A was calculated by applying the AE theory. Our results demonstrated that it is possible to estimate a nonlinear shear modulus by monitoring the changes in strain and μ due to kidney deformation. The magnitudes of A are higher when the compression is performed progressively and when using a plate attached to the transducer. Nevertheless, the values obtained for A are similar to those previously reported in the literature for breast tissue.
KW - Acoustoelasticity (AE)
KW - kidney
KW - nonlinearity
KW - shear modulus
KW - shear wave
UR - http://www.scopus.com/inward/record.url?scp=85038382307&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85038382307&partnerID=8YFLogxK
U2 - 10.1109/TUFFC.2017.2781654
DO - 10.1109/TUFFC.2017.2781654
M3 - Article
C2 - 29389651
AN - SCOPUS:85038382307
SN - 0885-3010
VL - 65
SP - 188
EP - 200
JO - IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
JF - IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
IS - 2
M1 - 8170331
ER -