X-ray Image Processing Correcting Residual Contrast Material
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Solution Overview
Problem
Conventional image processing and X-ray diagnosis apparatuses face challenges in accurately estimating the concentration of contrast material in the body during endovascular intervention treatments due to the beam hardening problem and residual contrast material influence, leading to inaccurate concentration measurements.
Innovation Solution
The apparatus acquires baseline, pre-injection, and target frames to account for residual contrast material, using log conversions and correction tables to offset the influence of residual contrast material, ensuring accurate concentration estimation by correcting observation values based on associated correction values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional beam hardening correction is applied using a correction table, then the observation value is corrected for beam hardening effects, but the correction becomes inaccurate when residual contrast material from previous injections is present
Solution Approach 1:
The patent segments the total contrast material signal into two distinct components: residual contrast material from previous injections and newly injected contrast material. By separately identifying and subtracting the residual component using the pre-injection frame, the system isolates the signal from the new injection, allowing accurate concentration estimation without interference from residual material.
Solution Approach 2:
The patent performs preliminary action by acquiring a pre-injection frame immediately before the new contrast material injection. This frame captures the residual contrast material distribution before the new injection occurs, enabling the system to subtract this residual component from the post-injection measurements. This preliminary capture of residual material state allows accurate isolation of the new contrast material signal.
2Productivity
If multiple contrast material injections are performed during endovascular intervention, then treatment can be conducted at different steps, but residual contrast material from previous injections contaminates subsequent measurements
Solution Approach 1:
The patent extracts the residual contrast material signal from the total measured signal by using the pre-injection frame as a reference. The system identifies and removes the contribution of residual contrast material from previous injections, leaving only the signal from the newly injected contrast material. This extraction process eliminates contamination and enables accurate concentration measurement despite multiple injections.
Solution Approach 2:
The patent implements feedback by using the pre-injection frame (which contains residual contrast material information) to correct the post-injection measurements. The system continuously updates the concentration estimation by subtracting the residual component identified from the pre-injection state, ensuring that each measurement reflects only the current injection's contrast material distribution and concentration.
3Object-affected harmful factors
If the correction curve is non-linear due to beam hardening effects, then beam hardening correction can be applied, but the relationship between observation value and actual concentration becomes complex and error-prone
Solution Approach 1:
The patent creates a copy of the residual contrast material distribution state by acquiring the pre-injection frame. This frame serves as a reference copy that captures the residual material's attenuation characteristics. By using this copy for subtraction, the system avoids the need to directly invert or complexly process the non-linear correction curve, simplifying the overall correction process while maintaining accuracy.
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 allows for precise estimation of contrast material concentration, eliminating the influence of residual material and improving perfusion analysis accuracy, enabling accurate judgment of treatment completion and concentration measurement.
Implementation Method 1
an X-ray tube 12, an X-ray collimator device 13
Implementation Method 2
an X-ray detector 16... that detects the X-rays which have passed through the subject P
Implementation Method 3
a baseline frame logarithm converting unit 31... a pre-injection frame logarithm converting unit 32... a target frame logarithm converting unit 33
Data Source
Figure 1
Figure 2(A)~2(B)
Figure 3A~3B
AI summary
An image processing apparatus (200) according to the present embodiment includes a correcting unit (234, 235, 236, 237, 238). The correcting unit (234, 235, 236, 237, 238) identifies, based on an observation value of a residual contrast material component that is injected to a subject before a predetermined timing and remains in the subject, the residual contrast material component and a new contrast material component that is newly injected to the subject after the predetermined timing regarding a contrast material component that is included in an image, and corrects an observation value of the contrast material component includes in the image.