Tissue Parameter Determination via Vessel Segmentation
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Solution Overview
Problem
Existing methods for determining tissue parameters from two-dimensional digital subtraction angiography x-ray images are unreliable due to the overlay of large vessels, which interfere with the analysis of blood perfusion through parenchyma, especially in the brain, and require costly three-dimensional perfusion recordings.
Innovation Solution
A method that segments vessels in x-ray images, interpolates pixel intensities to remove vessel interference, and determines tissue parameters based on time/intensity curves, using temporal segmentation and intensity threshold values to differentiate between vessel and tissue intensities, allowing for reliable determination of relative blood volume and flow maps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two-dimensional digital subtraction angiography x-ray images are used to determine tissue parameters, then the analysis can be performed with existing imaging equipment, but the determination is unreliable due to overlay of large vessels interfering with parenchyma analysis
Solution Approach 1:
The patent segments the x-ray image into multiple regions, identifying and separating vessel regions from parenchyma regions. By dividing the image into distinct zones and assigning different processing methods to each, the system eliminates the interference of large vessels from the tissue parameter calculation, thereby improving reliability without requiring new imaging equipment.
Solution Approach 2:
The patent extracts and removes the harmful influence of large vessels from the image analysis. By identifying vessel regions and excluding them from the parenchyma analysis, the system isolates the tissue of interest and performs accurate parameter determination on the remaining non-vessel areas, eliminating the interference that would otherwise compromise reliability.
2Reliability
If three-dimensional perfusion recordings are used to avoid vessel interference, then reliable tissue parameter determination is achieved, but the cost and complexity of the system increases
Solution Approach 1:
The patent creates a processed copy of the two-dimensional x-ray image that mimics the advantage of three-dimensional imaging. By segmenting and processing the 2D image to remove vessel interference, the system generates a corrected image representation that enables reliable tissue parameter determination without requiring actual 3D recording equipment, thus maintaining low system complexity while achieving high reliability.
3Measurement precision
If manual region selection is used to avoid vessels, then analysis accuracy improves, but the time required for analysis increases
Solution Approach 1:
The patent implements automated vessel identification and region segmentation that performs the analysis without requiring manual intervention. The system automatically detects vessel regions, separates them from parenchyma, and calculates tissue parameters, thereby achieving high measurement precision while eliminating the time loss associated with manual region selection and user-guided analysis.
Data Source
AI summary
A method for determining a tissue parameter of tissue that may be determined from passage of a contrast agent through the tissue based on a series of temporally consecutive two-dimensional digital subtraction angiography x-ray images showing propagation of the contrast agent in the tissue over time and a vascular system present in a region of the tissue includes locating at least some of the vessels of the vascular system by segmentation in the x-ray images. The method also includes assigning pixels showing segmented vessels an interpolation intensity determined by interpolation from intensities of at least some of the pixels bordering the segmented vessel, so that x-ray images from which vessels have been eliminated result. The method includes determining tissue parameters for at least some of the pixels of the series of x-ray images from which the vessels have been eliminated.