Non-invasive Microcirculatory Resistance Calculation via CT Fluid Dynamics
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Solution Overview
Problem
Current methods for evaluating coronary microcirculation function are inaccurate and invasive, and existing techniques that measure microcirculatory resistance, such as IMR, require intervention and are limited by high costs and operational risks, while non-invasive methods like coronary CTA cannot calculate resistance directly due to inability to measure coronary flow velocity at hyperemia states.
Innovation Solution
A method using CT images and fluid dynamics models to determine myocardial blood flow and coronary flow reserve, calculating blood flow velocity and pressure drops in coronary arteries to automatically and non-invasively compute the index of microcirculatory resistance, employing morphological operations, histogram analysis, and computational fluid dynamics to segment coronary arteries and calculate resistance indices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure guide wire intervention is used to measure IMR, then measurement precision is improved, but device complexity and operational risk increase
Solution Approach 1:
The patent replaces the mechanical pressure guide wire intervention system with a non-invasive CT imaging and fluid dynamics simulation system. The CT scanner captures coronary artery images, and computational fluid dynamics models calculate blood flow velocity and pressure without physical catheter insertion, thereby eliminating the complexity and risks of mechanical intervention while maintaining measurement capability
Solution Approach 2:
The patent introduces computational fluid dynamics simulation as an intermediary between the CT images and the microcirculatory resistance measurement. The simulation acts as a virtual mediator that translates anatomical images into functional hemodynamic parameters, avoiding the need for direct physical measurement with pressure guide wires
2Measurement precision
If pressure guide wire intervention is used to measure IMR, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The patent substitutes the complex mechanical intervention procedure with a non-invasive CT scanning and computational simulation workflow. The procedure becomes as simple as acquiring CT images and running automated fluid dynamics calculations, making it accessible to more centers and operators without specialized interventional skills
3Ease of operation
If coronary CTA is used for non-invasive evaluation, then ease of operation is improved, but measurement precision deteriorates due to inability to measure flow velocity
Solution Approach 1:
The patent performs preliminary action by using CT imaging to obtain detailed anatomical structure and cross-sectional area of coronary arteries before conducting fluid dynamics simulation. This pre-acquired geometric information serves as the foundation for subsequent virtual blood flow measurements, enabling the system to calculate flow velocity and pressure without direct measurement during the scan
Solution Approach 2:
The patent creates a virtual copy of the coronary artery system through CT imaging and reconstructs the three-dimensional anatomy. This digital replica is then used in fluid dynamics simulation to model blood flow behavior, allowing measurement of flow velocity and pressure in the virtual model without physically measuring in the patient
4Measurement precision
If invasive IMR measurement is performed, then measurement precision is improved, but loss of time increases due to procedural complexity
Solution Approach 1:
The patent replaces time-consuming mechanical catheterization procedures with rapid CT scanning and automated computational simulation. The entire measurement can be completed in a single CT scan session with subsequent automated processing, eliminating the need for separate catheterization procedures and reducing total measurement time
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for quick, accurate, and fully automatic calculation of microcirculatory resistance, reducing surgical difficulties and costs, enabling widespread clinical use with non-invasive measurements.
Implementation Method 1
A method using CT images and fluid dynamics models to determine myocardial blood flow and coronary flow reserve, calculating blood flow velocity and pressure drops in coronary arteries
Implementation Method 2
employing morphological operations, histogram analysis, and computational fluid dynamics to segment coronary arteries
Implementation Method 3
employing morphological operations, histogram analysis, and computational fluid dynamics to segment coronary arteries
Data Source
AI summary
A method for calculating an index of microcirculatory resistance includes determining myocardial volume by extracting myocardial images; locating a coronary artery inlet and accurately segmenting coronary arteries; generating a grid model required for calculation; determining myocardial blood flow in a rest state and CFR; calculating total flow at the coronary artery inlet in a maximum hyperemia state; determining flow in different blood vessels in a coronary artery tree in the maximum hyperemia state and then determining a flow velocity V1 in the maximum hyperemia state; obtaining the average conduction time in the maximum hyperemia state Tmn, and calculating a pressure drop ΔP from the coronary artery inlet to a distal end of a coronary artery stenosis, and a mean intracoronary pressure Pd at the distal end of the stenosis Pd=Pa−ΔP, and calculating the index of microcirculatory resistance.