Vascular Flow Simulation via Angiography Feedback
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Solution Overview
Problem
Current methods for diagnosing vascular diseases using three-dimensional imaging lack accurate temporal and spatial resolution of blood flow, making it difficult to precisely plan and perform minimally invasive interventions, especially in cases of stenosis where reduced blood flow is hard to visualize.
Innovation Solution
A computer-based method that uses a volume data set with local three-dimensional resolution and a temporal sequence of x-ray images to determine presence distributions by iteratively solving fluid dynamics movement equations, correcting presence distributions based on two-dimensional angiography sequences to achieve high-resolution, medically meaningful results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pure simulation of blood flow using Navier-Stokes equations is performed, then physical correctness of flow simulation is improved, but feedback to reality and measurement precision are worsened
Solution Approach 1:
The patent implements feedback by using measured presence distributions from angiography sequences to correct the simulated presence distributions. The correction factor is calculated as the ratio between measured and simulated presence distributions, and this feedback loop continuously adjusts the simulation results to match reality, resolving the contradiction between physical correctness and measurement precision.
Solution Approach 2:
The patent introduces an intermediary correction mechanism that bridges the simulation and measurement. The correction factor acts as an intermediary that transfers information from measured data to the simulation model, allowing the simulation to maintain its physical correctness while being adjusted to match actual measurements.
2Loss of information
If two-dimensional angiography sequences are used, then temporal information about blood flow is improved, but spatial resolution and visualization of stenoses are worsened
Solution Approach 1:
The patent resolves this contradiction by mapping the two-dimensional angiography data into a three-dimensional vascular model. The presence distributions from 2D angiography sequences are back-projected into the 3D volume data set, creating corrected presence distributions with three-dimensional spatial resolution while preserving the temporal information from the sequential images.
3Measurement precision
If correction of presence distributions is performed at every determination time, then accuracy is improved, but computation complexity increases
Solution Approach 1:
The patent applies partial correction by calculating correction factors only at specific determination times when angiography images are available, rather than continuously at every time point. This selective correction approach maintains accuracy where data is available while reducing computation complexity by avoiding unnecessary corrections at intermediate times.
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 accurate, high-resolution determination of blood flow dynamics, reducing patient x-ray exposure and computation complexity while improving the precision of vascular intervention planning by offering detailed spatial and temporal information.
Implementation Method 1
iterative resolution of fluid dynamics movement equations for determination times
Implementation Method 2
two-dimensional angiography sequences (showing the blood flow)
Implementation Method 3
The method is also known as digital subtraction angiography (DSA)
Data Source
AI summary
A computer receives a volume data set describing a vascular system with local three-dimensional resolution and a temporal sequence of groups of x-ray images. An acquisition time is assigned to each group of x-ray images comprising at least one x-ray image. Each x-ray image shows an actual presence distribution with local two-dimensional resolution for a substance in the vascular system, as defined at the respective acquisition time. The computer uses an initial presence distribution with local three-dimensional resolution for the substance, as defined for a start time, to determine further presence distributions with local three-dimensional resolution for the substance automatically for determination times by iterative resolution of fluid dynamics movement equations, which are per se location-independent. It automatically corrects the further presence distributions, if their respective determination time corresponds to one of the acquisition times, based on the temporally corresponding group of x-ray images.