In vivo mechanical modeling of multilayer biological soft tissue

Abstract

Methods: To test tissue in vivo, a robotically manipulated compression head instrumented with a 30 MHz high-resolution ultrasound probe and load-cells was designed and developed. The layer-specific material properties of the tissue were iteratively optimized, as part of a finite element model, by minimizing an objective function that considers the difference between experimentally measured and computed axial and lateral displacements of the tissue as well as reaction forces at the indenter. The technique was successfully validated using tissue mimicking agar-based phantoms of varying material properties and geometries. Following validation, ex vivo studies were performed followed by in vivo studies on 10 porcine stomachs.