Mechanical characterization of soft human tissue for applications in medicine
Event details
| Date | 11.12.2012 |
| Hour | 14:15 › 15:15 |
| Speaker | Prof. Edoardo Mazza, ETHZ, Switzerland |
| Location | |
| Category | Conferences - Seminars |
Two aspects will be considered in the talk: (i) characterization of biological membranes subjected to uniaxial and biaxial stress states, (ii) in vivo measurement of the mechanical response of soft human organs using the aspiration method.
(i) We investigate the multi-axial mechanical response of biological membranes, such as fetal membranes (amnio-chorion) and Glisson’s capsule. The predictive capabilities of hyperelastic viscoelastic constitutive model formulations are evaluated with respect to the experimental results obtained in different loading conditions. Unexpected features are observed, such as large lateral contractions (leading to in-plane area reduction!) in uniaxial tension, and biaxial stiffness by an order of magnitude larger compared to the uniaxial case. Semi-quantitative assessment of elastin and total collagen content in the membranes allows evaluating correlations between mechanical parameters and tissue microstructure. Implications of the observed deformation behavior on the clinical problem of premature rupture of fetal membranes are discussed.
(ii) Results will be presented from clinical studies with aspiration experiments on the liver during open abdominal surgery and intra-vaginal on the uterine cervix in the course of gestation. An extensive experimental campaign with measurements on patients undergoing hepatic resection has been recently completed. Histopathological characterization with biopsies taken at the measurement location allows analyzing the correlation between mechanical response and local tissue alterations. The measurements performed on the uterine cervix of 50 pregnant women at different gestational ages provide information on the corresponding changes in mechanical properties of the ectocervix. This procedure might form the basis for a new diagnostic method to complement morphological evaluations when predicting pre-term delivery.
(i) We investigate the multi-axial mechanical response of biological membranes, such as fetal membranes (amnio-chorion) and Glisson’s capsule. The predictive capabilities of hyperelastic viscoelastic constitutive model formulations are evaluated with respect to the experimental results obtained in different loading conditions. Unexpected features are observed, such as large lateral contractions (leading to in-plane area reduction!) in uniaxial tension, and biaxial stiffness by an order of magnitude larger compared to the uniaxial case. Semi-quantitative assessment of elastin and total collagen content in the membranes allows evaluating correlations between mechanical parameters and tissue microstructure. Implications of the observed deformation behavior on the clinical problem of premature rupture of fetal membranes are discussed.
(ii) Results will be presented from clinical studies with aspiration experiments on the liver during open abdominal surgery and intra-vaginal on the uterine cervix in the course of gestation. An extensive experimental campaign with measurements on patients undergoing hepatic resection has been recently completed. Histopathological characterization with biopsies taken at the measurement location allows analyzing the correlation between mechanical response and local tissue alterations. The measurements performed on the uterine cervix of 50 pregnant women at different gestational ages provide information on the corresponding changes in mechanical properties of the ectocervix. This procedure might form the basis for a new diagnostic method to complement morphological evaluations when predicting pre-term delivery.
Links
Practical information
- General public
- Free
Organizer
- IGM
Contact
- Géraldine Palaj