Double Subtraction Angiography Motion Isolation
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Solution Overview
Problem
Current methods for visualizing motion in angiographic images, such as digital subtraction angiography, face challenges in accurately assessing fast, irregular, or small object motion, especially when surrounded by moving structures, leading to difficulties in data interpretation.
Innovation Solution
The method involves performing a double subtraction technique on angiographic images, where a mask image is subtracted from a sequence of images to generate enhanced subtraction images, and then further subtracting these images to isolate the object's motion, facilitating the visualization of even small displacements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If digital subtraction angiography is performed to enhance object visualization, then the object of interest is enhanced, but motion assessment becomes difficult when motion is fast, irregular, or small
Solution Approach 1:
The patent applies segmentation by dividing the motion assessment into multiple temporal phases. A mask image representing a first phase is subtracted from angiographic images of subsequent phases, isolating motion-specific changes from static background structures. This phase-based segmentation enables accurate measurement of fast, irregular, or small motions that would be indistinguishable in conventional single-subtraction methods.
Solution Approach 2:
The patent implements preliminary action by acquiring a mask image at a defined reference phase before performing subtraction operations. This pre-acquired reference image establishes a baseline that removes static anatomical structures from subsequent motion analysis, allowing the system to focus computational resources on detecting and measuring actual motion artifacts in the angiographic sequence.
2Device complexity
If conventional subtraction methods are used, then processing is simple, but small object motion compared to image dimensions or surrounding object motion cannot be detected
Solution Approach 1:
The patent extends the conventional two-dimensional subtraction approach by introducing a temporal dimension through phase-based processing. By comparing angiographic images across multiple phases against a mask image, the system creates a temporal dimension in the subtraction process that amplifies small motions. This dimensional extension transforms subtle spatial displacements into detectable temporal variations without significantly increasing processing complexity.
Data Source
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AI summary
A method and an apparatus for motion visualization of a moving object in angiographic images are described. In a preferred embodiment of the method, first a mask image of the object of interest is acquired and a sequence of angiographic images of the object in different phases of motion of the object is acquired. Then, a first angiographic subtraction image and at least a second angiographic subtraction image are generated by subtracting the angiographic images from the mask image. Subsequently, a twice subtracted image is generated by subtracting the first angiographic subtraction image from the second angiographic subtraction image. In this way a double subtraction, i.e. a twice subtracted angiography is performed, to facilitate the assessment of the motion.