Characterization of frequency-dependent material properties of human liver and its pathologies using an impact hammer

Abstract 

The current methods for characterization of frequency-dependent material properties of human liver are very limited. In fact, there is almost no data available in the literature showing the variation in dynamic elastic modulus of healthy or diseased human liver as a function of excitation frequency. We show that frequency-dependent dynamic material properties of a whole human liver can be easily and efficiently characterized by an impact hammer. The procedure only involves a light impact force applied to the tested liver by a hand-held hammer. The results of our experiments conducted with 15 human livers harvested from the patients having some form of liver disease show that the proposed approach can successfully differentiate the level of fibrosis in human liver. We found that the storage moduli of the livers having no fibrosis (F0) and that of the cirrhotic livers (F4) varied from 10 to 20kPa and 20 to 50kPa for the frequency range of 0–80Hz, respectively.

Keywords: Impact test, Complex stiffness, Storage and loss moduli, Dynamic material properties of human liver, Material characterization of soft tissues