Deformable modeling of human liver with contact surface

Patient specific 3D finite element models have been developed using 4DCT (3D + time) image data for 5 liver cancer patients. Each model consists of the liver, tumors, left and right kidneys, stomach, spleen and body. Breathing motion of the liver, spleen and body is found and applied as displacement boundary conditions in the model. Sliding of the liver relative to the surrounding tissues is modeled using frictionless contact surfaces. Landmarks representing vessels bifurcation inside the liver are used for the model accuracy test. The goal of the study is to examine the effect of contact surface model on the performance of the deformable image registration of the liver. The accuracy of the model is improved by applying contact surface. Substantial displacement differences are observed between models with and without contact surface of the liver. The largest difference is in the Superior-Inferior (SI) followed by Anterior-Posterior (AP).