Mechanical Characterization of the Human Liver
The aspiration technique was used to characterize the mechanical behavior of the liver. Intra-operative application on human organs aimed at (i) tissue classification towards development of novel diagnostic procedures, and (ii) constitutive modeling of liver tissue. The first goal was achieved using scalar parameters extracted from time histories of aspiration pressure and deformation. Determination of parameters for nonlinear time dependent constitutive model formulations required solving the inverse problem. Glisson’s capsule was analyzed separately from parenchyma and was shown to behave as I 2-material. 207 aspiration measurements were performed on 33 patients. The influence of the contact force between the aspiration device and the liver was kept minimal in order to achieve a high reproducibility of the mechanical measurements. Histopathological characterization with biopsies taken at the measurement location allowed analyzing the influence of tissue microstructure. Tumors with high connective tissue content were shown to significantly affect the mechanical response.
KeywordsMagnetic Resonance Elastography Liver Capsule Aspiration Technique Inflation Test Aspiration Experiment
We thank Dr. S. Breitenstein, University Hospital Zurich, for performing the intraoperative measurements with the aspiration device. This work was partly supported by the CO-ME/NCCR research network of the Swiss National Science Foundation.
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