CT-Based FFR Calculation via CFD Simulation
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Solution Overview
Problem
Current methods for calculating coronary artery fractional flow reserve (FFR) using coronary CT angiography (CTA) are limited by the inability to measure coronary flow velocity in a hyperemia state, which restricts the clinical application of non-invasive FFR assessment.
Innovation Solution
A method that calculates FFR based on myocardial blood flow and CT images, involving segmentation of heart images, extraction of coronary artery trees, determination of myocardial blood flow and coronary flow reserve, and calculation of blood flow velocity and pressure drop to obtain FFR through computational fluid dynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If coronary CTA is used to assess stenosis degree, then anatomical information is obtained, but flow velocity in hyperemia state cannot be measured
Solution Approach 1:
The patent introduces computational fluid dynamics (CFD) simulation as an intermediary tool to bridge the gap between CT anatomical data and functional flow measurement. The CFD model acts as a virtual laboratory that takes CT images as input and calculates flow velocity and pressure drop through numerical computation, enabling non-invasive measurement of hyperemia state flow parameters without requiring actual intracoronary interventions.
Solution Approach 2:
The patent replaces the mechanical/invasive pressure wire measurement system with a computational simulation system. Instead of physically inserting wires into coronary arteries to measure pressure and flow directly (the traditional FFR method), the system uses CT-based 3D modeling and numerical CFD calculations to substitute the mechanical measurement process, achieving non-invasive functional assessment.
2Measurement precision
If traditional FFR measurement using pressure guide wire is used, then accurate pressure measurement is obtained, but invasive procedures and additional drugs are required
Solution Approach 1:
The patent creates a virtual copy of the coronary artery system through 3D reconstruction from CT images. This digital twin includes the complete anatomical structure, stenosis locations, and vessel geometry. The CFD simulation then runs on this virtual model to calculate pressure and flow parameters, providing accurate FFR values without requiring physical access to the actual coronary arteries, thereby eliminating invasive procedures and the need for intracoronary drugs.
3Ease of operation
If CTFFR is calculated using numerical methods, then non-invasive assessment is achieved, but clinical application is greatly limited
Solution Approach 1:
The patent enhances the adaptability of CTFFR by dynamically adjusting multiple parameters in the CFD simulation model, including blood viscosity, flow rate, pressure gradients, and vessel geometry. The system can accommodate different patient conditions, stenosis severities, and hyperemia induction methods by modifying these parameters, making the non-invasive assessment applicable to a wide range of clinical scenarios rather than being limited to specific conditions.
Data Source
AI summary
A method for calculating coronary artery fractional flow reserve 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 by edge detection of coronary artery volume data; determining myocardial blood flow in a rest state and CFR by non-invasive measurement; calculating the total flow at the coronary artery inlet in a maximum hyperemia state; determining the flow in different blood vessels in the coronary artery tree in the maximum hyperemia state and then determining flow velocity V1 in the maximum hyperemia state; using V1 as the flow velocity at the coronary artery inlet and calculating a pressure drop ΔP from the coronary artery inlet to a distal end of a coronary stenosis, and a mean intracoronary pressure Pd at the distal end of the stenosis Pd=Pa−ΔP, and calculating fractional flow reserve.