CT-Based Coronary FFR Estimation via Attenuation Gradients
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Solution Overview
Problem
Current methods for assessing coronary artery disease, such as diagnostic cardiac catheterization, are invasive and costly, and non-invasive CT-based methods for determining coronary flow velocity, pressure gradients, and fractional flow reserve are complex and computationally expensive, with disappointing results in predicting actual fractional flow reserve.
Innovation Solution
A non-invasive CT-based method that calculates coronary flow velocity, pressure gradient, and fractional flow reserve using patient-specific transluminal attenuation gradient and arterial input function data, eliminating the need for invasive procedures and providing a direct correlation between contrast dispersion and hemodynamic parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If diagnostic cardiac catheterization is used to determine FFR, then measurement precision is improved, but device complexity and patient risk increase due to invasive procedures
Solution Approach 1:
The patent replaces the mechanical invasive catheterization system with a non-invasive CT-based computational system. Specifically, it substitutes physical pressure wires and catheters with CT imaging and computational fluid dynamics modeling to derive FFR, eliminating the need for invasive vascular access while maintaining functional assessment capability
Solution Approach 2:
The patent creates a virtual copy of the coronary circulation system through CT-based 3D reconstruction and computational modeling. This virtual model replicates the hemodynamic behavior of the actual coronary arteries, allowing FFR measurement without physical intrusion into the patient's vasculature
2Device complexity
If CT-based computational fluid dynamics modeling is used to estimate FFR, then device complexity is reduced, but productivity decreases due to computational expense and extended processing time
Solution Approach 1:
The patent performs preliminary actions by acquiring high-resolution CT angiography data and creating 3D coronary models during the initial imaging phase. This preparatory work is done before the FFR calculation is needed, allowing the computational analysis to proceed more efficiently when clinical decision-making requires the results
Solution Approach 2:
The patent changes key parameters of the computational model, specifically using contrast attenuation values from CT images as surrogate markers for blood flow and pressure. This parameter substitution transforms the computational problem from requiring detailed flow measurements to using readily available imaging data, significantly reducing computation time
3Object-affected harmful factors
If non-invasive CT methods are used to assess coronary lesions, then patient risk is reduced, but measurement precision deteriorates due to inability to directly measure pressure gradients
Solution Approach 1:
The patent introduces contrast agent attenuation as an intermediary parameter that correlates with blood flow and pressure characteristics. Instead of directly measuring pressure gradients, the system uses CT attenuation values as a mediator to infer hemodynamic parameters, bridging the gap between non-invasive imaging and functional assessment
Solution Approach 2:
The patent fundamentally changes the measurement parameter from direct pressure (requiring invasive sensors) to contrast attenuation (measurable by CT). By establishing mathematical relationships between attenuation patterns and hemodynamic parameters, the system achieves pressure gradient assessment through a completely different physical quantity
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
Enables non-invasive assessment of coronary artery stenosis severity, reducing patient risk and cost by using CT scans to determine functional significance of coronary lesions without the need for additional procedures or data transmission, providing accurate estimates of coronary flow reserve and pressure gradients.
Implementation Method 1
obtaining a patient specific transluminal attenuation gradient (TAG) for the coronary artery of the patient
Data Source
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Figure 2A~2D
AI summary
An embodiment in accordance with the present invention provides a method for non-invasively determining the functional severity of coronary artery stenosis. The method includes gathering patient-specific data related to concentration of a contrast agent within a coronary artery of a patient using a coronary computed tomography angiography scan (CCTA). The patient-specific data is used to calculate a patient-specific transluminal attenuation gradient for the coronary artery of the patient. The patient specific transluminal attenuation gradient is used to determine an estimate of a coronary flow velocity, pressure gradient, loss coefficient, coronary flow reserve, and/or fractional flow reserve for the patient. Coronary flow velocity, pressure gradient, loss coefficient, coronary flow reserve, and fractional flow reserve can then be used to estimate the functional severity of coronary artery stenosis.