Non-Invasive Urodynamic Analysis Using the Computational Fluid Dynamics Method Based on MR Images

Objective: The pressure-flow rate test is invasive. In addition, several nomograms are used and an exact standardization cannot be provided. For this reason, the search for new methods that are called non-invasive by several authorities, and that will provide clinical data similar to urodynamics, is ongoing. The aim of this study is to report a non-invasive, newly developed technique for the assessment of bladder pressure and flow rate using Computational Fluid Dynamics (CFD). Material and Methods: Participants consisted of 10 voluntary males. All data referring to volunteer demographics were recorded. Magnetic resonance imaging (MRI) was performed for the reconstruction of the bladder. After the MRI process, the peak flow-rates were measured with a uroflowmeter. Using CFD, first, by applying a pressure of 20 cm H2O to the bladder wall the geometry of the bladder was obtained from processing of MR images and flow rates were determined. Secondly, the wall pressures needed to provide flow rates obtained from uroflowmetry were calculated. Results: The average values of the measured flow rate and the computed flow rate were calculated as 21.9 +/- 7.8 ml/s and 24.6 +/- 2.4 ml/s, respectively. It was found that the flow rates obtained from the uroflowmetry and the flow rates calculated by CFD were consistent with each other (p < 0.05). The average value of the computed bladder pressure was found to be 16.8 +/- 9.6 cm H2O. Conclusion: CFD, which is widely used in biomechanical applications as well as engineering problems, was used to simulate the flow inside three dimensional bladder models obtained from MR images. By comparing the results achieved by this method and the results obtained by uroflowmetry, a significant correlation was found. A novel noninvasive alternative method was developed to investigate the pressure-flow rate relationship in the bladder which may also provide a basis for theoretical analysis.