Determination of the Mechanical Properties of Soft Human Tissues through Aspiration Experiments

Abstract

Mechanical models for soft human organs are necessary for a variety of medical applications, such as surgical planning, virtual reality surgery simulators, and for diagnostic purposes. An adequate quantitative description of the mechanical behaviour of human organs requires high quality experimental data to be acquired and analyzed. We present a novel technique for the acquisition of such data from soft tissues and its post processing to determine some parameters of the tissue's mechanical properties. A small tube is applied to the target organ and a weak vacuum is generated inside the tube according to a predefined pressure history. A video camera grabs images of the deformation profile of the aspirated tissue, and a pressure sensor measures the correspondent vacuum level. The images are processed and used to inform the fitting of uniaxial and continuum mechanics models. Whilst the aspiration test device has been designed to fulfill the requirements for in-vivo applications, for measurements obtained during open surgery, initial experiments performed on human cadaveric tissues demonstrate the ability to both differentiate between different organs and also between normal and diseased organs on the basis of the derived mechanical properties.

Capture and modeling of non-linear heterogeneous soft tissue

“…Other techniques in material sciences also directly measure the parameters of constitutive models, such as the tensile test [Hart 1967], or apparatus for in-vivo measurement through tissue aspiration [Nava et al 2003] or indentation [Ottensmeyer and Salisbury Jr. 2004].…”

Virtual Reality Based Simulation of Hysteroscopic Interventions

“…Material parameters for the offline FE deformation computations are obtained in vivo with a tissue aspiration device (Nava, Mazza, Kleinermann, Avis, McClure, & Bajka, 2004). In the second step, the offline computation enables the use of more advanced, and thus more accurate, tissue modeling techniques.…”

Computational Models for Image-Guided Robot-Assisted and Simulated Medical Interventions

“…There are three different sources of rheological data : exvivo testing where a sample of a tissue is positioned inside a testing rig [71], [72]; in-vivo testing where a specific force and position sensing device is introduced inside the abdomen to perform indentation [73], [74]; Image-based elastometry from ultrasound, Magnetic Resonance Elastometry [75], [76] or CTscan imaging.…”