Vessel Geometry Reconstruction Using Contrast Dynamics
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Solution Overview
Problem
Current methods for determining vessel geometry and flow characteristics in vascular systems require high patient load with contrast agents and X-radiation, and only provide incomplete diagnostic information due to fixed projection geometry, limiting their accuracy and applicability.
Innovation Solution
An investigation system using an X-ray device to generate differently oriented projections and a data processing unit that reconstructs three-dimensional vessel geometry and flow characteristics from a single temporal sequence of projections, leveraging contrast agent dynamics to reduce patient strain and improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If two image sequences are generated to determine vessel geometry and flow characteristics, then diagnostic information completeness is improved, but patient load with contrast agent and X-radiation increases
Solution Approach 1:
The patent combines the determination of vessel geometry and flow characteristics into a single integrated process using one image sequence. The system simultaneously reconstructs three-dimensional vessel models and determines flow characteristics from the same temporal sequence of projections, eliminating the need for separate image sequences and thereby reducing patient exposure to contrast agent and radiation while maintaining complete diagnostic information.
Solution Approach 2:
The evaluation system is designed to perform multiple functions using a single image sequence: it reconstructs vessel geometry in three dimensions, determines flow characteristics, and provides complete diagnostic information for various vascular conditions. This multi-functional approach allows the system to replace what previously required two separate image sequences, reducing the harmful factors while maintaining comprehensive diagnostic capability.
2Object-affected harmful factors
If projections are taken from a constant direction to reduce patient load, then radiation exposure is reduced, but flow information completeness deteriorates due to occlusion from other vessels
Solution Approach 1:
The patent employs dynamic projection acquisition where the projection direction changes over time within a single temporal sequence. The X-ray device captures projections from multiple directions as the contrast agent flows through the vascular system, allowing the system to reconstruct complete three-dimensional vessel geometry and obtain comprehensive flow information without requiring the patient to be exposed to radiation from multiple fixed directions separately.
Solution Approach 2:
The system transitions from two-dimensional fixed projection imaging to three-dimensional dynamic imaging by acquiring projections from multiple directions over time. This dimensional expansion allows the reconstruction of complete vessel geometry and flow characteristics, overcoming the occlusion limitations of single-direction projections while maintaining reduced radiation exposure through a single temporal sequence acquisition.
3Object-affected harmful factors
If a single temporal sequence of projections is used to reduce patient load, then contrast agent and radiation exposure is reduced, but measurement data quantity decreases
Solution Approach 1:
The patent exploits temporal changes in contrast agent concentration as an additional parameter dimension within the single image sequence. By analyzing the dynamic changes in X-ray attenuation over time as the contrast bolus passes through different vessels, the system extracts sufficient information to reconstruct complete three-dimensional vessel geometry and determine comprehensive flow characteristics, effectively converting time-based parameter changes into spatial and functional information.
Solution Approach 2:
The contrast agent bolus serves as an intermediary that carries diagnostic information through the vascular system. The system uses the temporal dynamics of the contrast agent's passage—its concentration changes over time at different locations—as a mediator to infer vessel geometry and flow characteristics. This approach allows the extraction of comprehensive diagnostic information from a single temporal sequence, compensating for the reduced quantity of direct structural measurements.
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
The system achieves high accuracy in reconstructing vessel geometry and flow characteristics with reduced patient exposure to contrast agents and X-radiation, enabling the reconstruction of complex vessel geometries that conventional methods struggle with.
Implementation Method 1
an X-ray device for the generation of differently oriented projections of the vessel system
Implementation Method 2
the specific increase and decrease of X-ray attenuation—observed as 'time-intensity curves' (TICs) in the projection images
Data Source
AI summary
The invention relates to a method and a system for the simultaneous reconstruction of the three-dimensional vessel geometry and the flow characteristics in a vessel system. According to one realization of the method, vessel segments (41) of a parametric models are fitted to differently oriented X-ray projections (P1, Pk, PN) of the vessel system that are generated during the passage of a bolus of contrast agent, wherein the fitting takes the imaged contrast agent dynamics and physiological a priori knowledge into account. In an alternative embodiment, the vessel geometry is reconstructed progressively along each vessel, wherein a new segment of a vessel is added based on the continuity of the vessel direction, vessel radius and reconstructed contrast agent dynamics.