Tomosynthesis Contrast Agent Concentration Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current tomosynthesis scans face challenges in accurately measuring and differentiating contrast agent concentration changes due to inconsistent data acquisition during the rapid enrichment phase of malignant tumors, as the existing methods take too long and result in temporally varying contrast agent concentrations.
Innovation Solution
A dual-energy subtraction method using low-energy and high-energy x-ray images, where low-energy images are subtracted from high-energy images to isolate contrast agent concentration, combined with temporal dual-energy subtraction to track the contrast agent's course over time, allowing for precise reconstruction and visualization of contrast agent dynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If a standard tomosynthesis scan is performed to capture contrast agent concentration changes, then the scan covers a sufficient volume segment, but the acquisition time is too long (up to 25 s) causing temporally varying contrast agent concentrations and inconsistent data
Solution Approach 1:
The tomosynthesis acquisition is divided into multiple subsets of projection images, where each subset is acquired at a different angle range. This segmentation allows the total acquisition time to be distributed across multiple shorter intervals, reducing the temporal variation of contrast agent concentration within each subset while maintaining comprehensive volume coverage through combination of all subsets.
2Speed
If fast imaging is performed to capture rapid contrast agent enrichment in malignant tumors, then the temporal resolution is improved, but the measurement precision of contrast agent concentration deteriorates due to insufficient data from limited angles
Solution Approach 1:
Multiple subsets of projection images acquired at different angle ranges are merged through iterative reconstruction algorithms to form complete tomographic images. This merging process combines data from multiple acquisitions taken at different times, using temporal interpolation and consistency constraints to reconstruct accurate contrast agent concentration measurements despite the time elapsed between subsets.
3Measurement precision
If multiple high-energy images are acquired to improve contrast agent concentration visualization, then the measurement precision is improved, but the radiation dose increases
Solution Approach 1:
Instead of acquiring complete sets of projection images at multiple energy levels, the method acquires only partial subsets of high-energy projection images. The missing data is reconstructed using iterative algorithms that leverage temporal information from low-energy images and physical constraints of the imaging geometry, achieving adequate contrast agent visualization with reduced radiation exposure.
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 measurement and visualization of contrast agent concentration and its dynamics, improving the differentiation of malignant and benign lesions by synchronizing the tomosynthesis scan with the contrast agent's dynamic phases, reducing radiation exposure, and enhancing spatial and temporal resolution.
Implementation Method 1
generate a two-dimensional low-energy image with a low x-ray energy... Generate one or more two-dimensional high-energy images with a high x-ray energy
Implementation Method 2
the x-ray photons in the generation of the high-energy image have a sufficient amount of energy in order to strip an electron of a contrast agent atom from the k-shell, such that the contrast agent absorbs at least a portion of the x-ray radiation
Implementation Method 3
the spectrum (more precisely the focal point of the spectrum) of the x-rays for generation of the high-energy images is markedly above the k-edge of the contrast agent, while the spectrum (more precisely the focal point of the spectrum) of the x-rays to generate the low-energy image is markedly below this k-edge
Data Source
AI summary
In an imaging method and a tomosynthesis apparatus, a two-dimensional low-energy image of the predetermined volume segment is obtained after administration of a contrast agent, followed by a two-dimensional high-energy image and then a high-energy tomosynthesis of the predetermined volume segment is obtained with a high total radiation dose that is significantly higher than the low radiation dose. The two-dimensional low-energy image is subtracted from the two-dimensional high-energy image to generate a result with which the concentration of the contrast agent is visible. Additionally, in a time interval in which an enrichment or a washing-out of the contrast agent occurs within the predetermined volume segment, a tomosynthesis of the predetermined volume segment is automatically implemented to show the concentration of the contrast agent in the predetermined volume segment.