Numerical and experimental study of the mechanics of Bladder filling process

Abstract

The bladder is a very important organ and its main function is to store and release urine, which causes constant loading and volume change. The bladder wall is a smooth muscle reservoir that is capable of shrinking and expanding, depending on the volume of urine stored within it. Its movement has direct effect on the diagnosis and treatment of medical conditions of bladder and adjacent organs such as the prostate. It has been reported that the bladder filling have direct influence on the positioning accuracy of the prostate in a Radiotherapy or brachytherapy process. A detailed understanding of the liquid filling process within an in vivo condition is very important for studying their mechanics and interaction with other organs. In this work, a systematic approach has been developed based on realistic MRI subject data to study the deformation of bladder during filling. Experimental work on water filling with isolated balloon and bladder phantom has been performed and the results were used to validate a numerical finite element model. Theapproach was then used to simulate the deformation of the bladder within the pelvis system and the numerical results  were compared to the volume–pressure curves during bladder filling in vitro and in vivo.