Coronary Artery FFR Determination via CFD and Lumped Parameter Segmentation
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Solution Overview
Problem
Current methods for determining patient-specific cardiovascular information, such as fractional flow reserve (FFR), require complex calculations and include uncertainty due to the use of closed lumped parameter models that are not patient-specific, leading to inaccuracies in blood flow rate determination and increased calculation time.
Innovation Solution
A method that applies a computational fluid dynamics model and a simplified lumped parameter model only to the portion of the blood vessel of interest, using three-dimensional shape models of coronary arteries and setting resistance values based on the ratio of blood flow rates and lengths of the arteries, eliminating the need for volume or mass calculations of cardiac muscles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a closed lumped parameter model including the aorta and whole cardiovascular system is used, then comprehensive hemodynamic analysis is achieved, but calculation complexity and uncertainty increase
Solution Approach 1:
The patent segments the cardiovascular system into a coronary artery subsystem and a rest-of-body subsystem. The CFD model focuses only on the coronary arteries of interest, while the lumped parameter model represents the rest of the cardiovascular system. This segmentation reduces the complexity of the CFD model while maintaining comprehensive hemodynamic analysis through the coupled approach.
Solution Approach 2:
The patent extracts the aorta and other major vessels from the CFD model and represents them using a simplified lumped parameter model. This extraction reduces the number of elements in the CFD model, decreasing calculation complexity and uncertainty while preserving the essential hemodynamic characteristics through the lumped parameter representation.
2Measurement precision
If myocardial tissue volume calculation is performed using scaling law, then patient-specific blood flow rates are determined, but segmentation work and uncertainty increase
Solution Approach 1:
The patent extracts the requirement for myocardial tissue volume calculation by using a different approach. Instead of calculating volumes through segmentation, the method uses centerline lengths of coronary arteries from 3D models, which can be obtained without complex segmentation of myocardial tissue, thereby reducing uncertainty and complexity.
Solution Approach 2:
The patent changes the parameter used for blood flow rate determination from myocardial tissue volume to coronary artery centerline length. This parameter change eliminates the need for complex segmentation work while still providing patient-specific blood flow rate estimates through the relationship between artery length and flow characteristics.
3Device complexity
If standard representative values are used for hemodynamic parameters, then model simplicity is maintained, but patient-specific accuracy decreases
Solution Approach 1:
The patent changes from using standard representative values to using patient-specific parameters derived from individual coronary artery geometry. By calculating centerline lengths from patient-specific 3D models and using these to determine blood flow rates, the method maintains model simplicity while improving parameter accuracy for individual patients.
Data Source
AI summary
The present invention relates to a method for determining patient-specific blood vessel information. More specifically, the present invention relates to a method for determining patient-specific cardiovascular information by applying a simplified coronary circulation model thereto. Furthermore, the present invention relates to a method for determining a blood flow rate for branches of a blood vessel having originated from an artery of each patient. According to the present invention, the method for determining cardiovascular information by using a computer system comprises the steps of: receiving image data including a plurality of coronary arteries having originated from the aorta; processing the image data so as to generate a three-dimensional shape model of the plurality of coronary arteries; simulating a blood flow for the generated three-dimensional shape model of the plurality of coronary arteries; and determining a fractional flow reserve (FFR) of the respective coronary arteries with the blood flow simulation result. In the blood flow simulation step for the three-dimensional shape model of the plurality of coronary arteries, a computational fluid dynamics model is applied to the three-dimensional shape model of the coronary arteries, and a centralized parameter model to be combined with the computational fluid dynamics model uses a simplified coronary circulation model including coronary arteries, capillaries of the coronary arteries, and coronary veins.