Spectral CT Blood Flow Measurement Without Image Reconstruction
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Solution Overview
Problem
Existing angiographic techniques for measuring blood flow parameters in vasculature suffer from inaccuracies due to the inability to effectively isolate contrast agent attenuation from background materials, leading to unreliable calculations of parameters like FFR, iFR, CFR, TIMI flow grade, IMR, and HMR.
Innovation Solution
A computer-implemented method involving spectral CT projection data analysis to isolate contrast agent data, allowing for accurate sampling at regions of interest without reconstructing images, thereby improving the isolation of contrast agent attenuation from background materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional angiographic techniques are used to measure blood flow parameters, then the measurement process is simpler, but the measurement precision deteriorates due to inability to isolate contrast agent attenuation from background materials
Solution Approach 1:
The patent segments the X-ray attenuation data into different components by analyzing spectral data at multiple energy levels. The contrast agent attenuation is separated from background material attenuation through energy-dependent decomposition, allowing precise isolation of the contrast agent signal without being contaminated by surrounding tissues.
Solution Approach 2:
The patent adds the energy dimension to the traditional single-energy angiographic measurement. By acquiring and analyzing spectral CT data across multiple energy intervals, the system transforms a 2D projection problem into a 3D problem (spatial x + energy), enabling differentiation of materials with similar attenuation at single energy levels.
2Measurement precision
If image reconstruction is performed to analyze blood flow, then visual interpretation is easier, but measurement precision deteriorates due to inaccuracies introduced by reconstruction
Solution Approach 1:
The patent performs material decomposition and contrast agent isolation in the projection domain before image reconstruction. By separating the contrast agent signal from background materials at the projection stage, the method avoids introducing reconstruction-related inaccuracies that would contaminate the blood flow measurement.
Solution Approach 2:
The patent replaces the traditional reconstruction-then-measurement workflow with a direct projection-domain analysis approach. Instead of reconstructing images and then measuring blood flow parameters, the system performs spectral decomposition and velocity calculation directly on the projection data, substituting the mechanical reconstruction step with a mathematical transformation in Fourier space.
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 method provides more reliable blood flow data, resulting in more accurate calculations of blood flow parameters by avoiding inaccuracies introduced by image reconstruction, thus enhancing the precision of measurements.
Implementation Method 1
spectral CT projection data representing X-ray attenuation within the vasculature at a plurality of energy intervals
Data Source
AI summary
A computer-implemented method of measuring a blood flow parameter in a vasculature, is provided. The method includes: analyzing spectral CT projection data to isolate from the spectral CT projection data, contrast agent projection data representing the flow of the injected contrast agent; sampling the contrast agent projection data at one or more regions of interest in the vasculature to provide temporal blood flow data at the one or more regions of interest; and calculating, from the temporal blood flow data, a value of one or more blood flow parameters at the one or more regions of interest.