Iterative CFD-LPM Coupling for Subject-Specific Blood Vessel Simulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current blood flow simulation methods for subject-specific three-dimensional blood vessel models fail to accurately reflect the hemodynamic characteristics of microvascular beds, particularly when stenosis occurs, due to the use of parameters that do not account for the shape of the blood vessel, leading to inaccurate boundary conditions and low simulation accuracy.
Innovation Solution
A novel CFD-LPM-coupled blood flow simulation method that updates microvascular bed parameters based on the shape of the blood vessel by iteratively recalculating blood flow rates and resistances, ensuring that the LPM model parameters reflect the physiological changes caused by stenosis and vessel shape, thereby improving the accuracy of hemodynamic simulations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional LPM model parameters are used without updating based on vessel shape, then the simulation process is simple and fast, but the accuracy of hemodynamic simulation is low
Solution Approach 1:
The patent applies dynamics by making the LPM model parameters dynamic rather than static. The microvascular bed parameters (resistance and compliance) are updated iteratively based on the CFD-simulated blood flow rates and the three-dimensional blood vessel shape. This allows the model to adapt to different physiological states and vessel geometries, resolving the contradiction between simulation simplicity and accuracy.
Solution Approach 2:
The patent implements feedback by creating an iterative coupling between the CFD model and LPM model. The CFD simulation provides blood flow rates that feed back into the LPM model to update its parameters, which then provide updated boundary conditions back to the CFD model. This feedback loop ensures that the simulation accuracy improves while maintaining computational efficiency.
2Reliability
If fixed LPM model parameters are used, then the calculation time is short, but the hemodynamic characteristics cannot reflect physiological changes caused by stenosis
Solution Approach 1:
The patent applies preliminary action by performing the CFD simulation first to obtain the blood flow rate distribution before updating the LPM model parameters. This preliminary calculation provides the necessary input data for subsequent parameter updates, ensuring that the physiological accuracy is achieved without unnecessary computational time being wasted on incorrect parameter assumptions.
Solution Approach 2:
The patent changes the parameters of the LPM model dynamically based on the CFD simulation results. The microvascular bed resistance and compliance parameters are recalculated using the blood flow rates obtained from the CFD model and the three-dimensional vessel shape. This parameter change allows the model to accurately reflect physiological changes caused by stenosis while maintaining reasonable calculation time through targeted updates rather than complete recalculations.
3Measurement precision
If subject-specific three-dimensional blood vessel model is used with conventional boundary conditions, then the anatomical accuracy is high, but the boundary conditions do not accurately represent the microvascular bed characteristics
Solution Approach 1:
The patent applies segmentation by dividing the vascular system into two distinct models: a three-dimensional CFD model for the macrovascular structure and a lumped parameter LPM model for the microvascular bed. Each model is optimized for its specific function, with the CFD model handling anatomical accuracy and the LPM model handling microvascular characteristics. This segmentation allows for accurate boundary conditions without excessive overall complexity.
Solution Approach 2:
The patent uses an intermediary coupling mechanism between the CFD model and LPM model. The blood flow rates from the CFD model serve as intermediaries to update the LPM model parameters, which then provide updated boundary conditions back to the CFD model. This intermediary feedback mechanism ensures that the boundary conditions accurately represent microvascular bed characteristics while maintaining model manageability through systematic integration.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
In a simulation method according to the present invention, when performing a blood flow simulation by coupling a CFD model and an LPM model, a blood flow simulation for the CFD model is performed under a set initial condition and a boundary condition, a blood flow rate Qi for each outlet and a total outflow blood flow Qtot_cfd of the CFD model are calculated by a blood flow simulation, the microvascular bed parameters of the LPM model are updated using the blood flow rate for each outlet and the total outflow blood flow of the CFD model, the boundary condition of an outlet of the CFD model is updated using the updated LPM model, and the simulation is repeatedly performed until a convergence condition of the blood flow simulation for the CFD model is satisfied, thereby calculating blood flow information for the three-dimensional blood vessel model.