C-Arm X-Ray Magnification Correction for Vessel Sizing
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Solution Overview
Problem
C-arm x-ray imaging systems magnify target elements due to divergent x-rays, making it difficult to estimate real physical dimensions, particularly in procedures like stent placement where accurate vessel sizing is crucial.
Innovation Solution
A spatial dimension determination device that uses movement parameters and image analysis to establish a dimensional relation between image dimensions and real dimensions, allowing for accurate determination of target element sizes within an object, preferably using a catheter or needle introduced by a robotic unit and x-ray imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If x-ray imaging is used to visualize target elements, then the target element becomes visible in the images, but the image dimension is magnified and does not reflect the real physical dimension
Solution Approach 1:
A reference object with known real dimensions is introduced as an intermediary between the x-ray imaging system and the target element. By placing this reference object at the same location as the target element and using it to calculate a correction factor, the system can compensate for the magnification effect and determine accurate real dimensions of the target element.
Solution Approach 2:
The system changes the parameter of dimensional measurement by introducing a correction factor that transforms the magnified image dimension into the real physical dimension. This correction factor is calculated based on the ratio between the known real dimension of the reference object and its measured image dimension, allowing accurate dimensional assessment of the target element.
2Ease of operation
If the location of the target element between the x-ray source and detector is unknown, then the imaging system can operate without precise positioning, but the magnification factor cannot be determined
Solution Approach 1:
The reference object serves as a mediator that bridges the gap between unknown target element location and needed dimensional accuracy. By placing the reference object at the target element's location and using its known dimensions, the system can calculate the magnification factor without needing to know the precise distance between the x-ray source, detector, and target element.
Solution Approach 2:
The system uses feedback from the reference object's known dimensions to calculate and apply a correction factor. The measured image dimension of the reference object is compared with its known real dimension, and this feedback loop enables the system to determine the magnification factor and compensate for it in subsequent 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
Enables precise assessment of target element dimensions within an object, such as vessels, by determining a ratio between image and real dimensions, facilitating the selection and placement of appropriately sized stents during minimally invasive procedures.
Implementation Method 1
A C-arm x-ray imaging system comprises an x-ray source and an x-ray detector for generating x-ray images of a target element arranged between the x-ray source and the x-ray detector. Since the x-rays generated by the x-ray source are divergent, the target element is shown in the x-ray images in a magnified way.
Data Source
AI summary
The invention relates to a spatial dimension determination device for determining a spatial dimension of a target element like a vessel within an object (9), for instance, within a person. Movement parameters describing a movement of an introduction element (4) moved by a moving unit (2) like a robot and several images showing the introduction element are used for determining a dimensional relation between an image dimension and a real dimension. A further image showing the target element is provided, wherein a real dimension of the target element is determined based on an image dimension of the target element in the further image and based on the determined dimensional relation. An unknown real physical dimension of a target element within the object can therefore accurately be determined from an image of the target element by using, inter alia, the movement parameters.