Dual-Energy CT Contrast Agent Separation via Spectral Absorption
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Solution Overview
Problem
Conventional X-ray imaging methods struggle to simultaneously and accurately represent two different contrast agents due to their similar spectral absorption behaviors, leading to poor image separation and increased radiation doses, especially in dual-energy CT imaging.
Innovation Solution
An ensemble of X-ray contrast agents with significantly different absorption changes between two different X-ray photon energies is used, allowing for clear distinction and separate representation of regions affected by each agent through dual-energy CT image recordings, employing a material decomposition method that generates separate image datasets for each contrast agent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional iodine-based contrast agents are used for both embolization representation and blood flow imaging, then the imaging process is simplified, but the separation of the two contrast agents becomes impossible or very difficult due to their similar absorption spectra
Solution Approach 1:
The patent applies local quality by selecting different energy ranges for detecting different contrast agents. The first contrast agent (iodine-based) is detected primarily in the lower energy range (30-50 keV) where it has strong absorption, while the second contrast agent is detected in the higher energy range (50-100 keV) where it has stronger absorption. This energy-based spatial separation in the spectral domain allows clear distinction between the two agents without complicating the imaging process.
2Measurement precision
If subtraction techniques are used to separate the two contrast agents, then separate representation is achieved, but the radiation dose to the patient is increased due to multiple CT recordings
Solution Approach 1:
The patent employs periodic action by using alternating energy ranges during a single CT scan acquisition. The detection system periodically switches between lower and higher energy ranges to capture signals from different contrast agents simultaneously, eliminating the need for multiple sequential scans and associated subtraction techniques, thereby reducing radiation exposure while maintaining separation accuracy.
Solution Approach 2:
The patent transitions from temporal separation (multiple scans at different times) to spectral separation (simultaneous detection at different energies). By adding the energy dimension to the detection process, the system can distinguish between contrast agents in a single scan, avoiding repeated radiation exposure required by temporal separation methods.
3Measurement precision
If dual-energy imaging is used to separate contrast agents with similar spectral behavior, then separate representation is attempted, but the material decomposition results in very imprecise images with intense noise
Solution Approach 1:
The patent applies parameter changes by optimizing the energy range selection based on the specific absorption characteristics of each contrast agent. Instead of using arbitrary dual-energy settings, the system selects energy ranges (30-50 keV for iodine, 50-100 keV for the second agent) that maximize the contrast difference between agents while minimizing noise, thereby achieving precise material separation with high image quality.
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 approach enables precise and accurate simultaneous representation of functional regions with reduced radiation dose and improved image quality, overcoming the limitations of conventional methods by distinguishing between contrast agents with different absorption behaviors.
Implementation Method 1
The second X-ray contrast agent has an X-ray absorption the change of which between at least two different X-ray photon energies differs significantly from the change in the X-ray absorption of the first contrast agent between the at least two different X-ray photon energies
Data Source
AI summary
An ensemble of at least two X-ray contrast agents includes X-ray contrast agent and a second X-ray contrast agent. The second X-ray contrast agent has an X-ray absorption whose change between at least two different X-ray photon energies differs significantly from the change of the X-ray absorption of the first X-ray contrast agent between the at least two different X-ray photon energies. An X-ray imaging method, an image reconstruction device, an X-ray imaging system are also disclosed.