Shear Wave Elastography Filtering for Static Deformation Artifacts
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Solution Overview
Problem
Conventional shear wave elastography techniques suffer from artifacts due to static deformations caused by probe movement and patient organ movements, which degrade the accuracy of viscoelastic property measurements in biological tissues.
Innovation Solution
A method involving a finite impulse response filter is applied to separate and attenuate the static-deformation component from the shear-propagation component in viscoelastic media, using a highpass filter with defined passband and stopband characteristics to enhance the measurement of viscoelastic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If shear wave elastography is used to measure tissue viscoelastic properties, then viscoelastic parameters can be determined, but artifacts due to static deformations degrade measurement accuracy
Solution Approach 1:
The movement signal is segmented into two distinct components: a static-deformation component (low spatial frequencies) and a shear-propagation component (high spatial frequencies). This segmentation allows separate processing of each component, enabling the static deformation artifacts to be filtered out while preserving the shear wave information needed for viscoelastic measurement.
Solution Approach 2:
The static-deformation component is extracted and removed from the total movement signal. By isolating and eliminating this harmful component, the measurement accuracy of viscoelastic properties is improved without being compromised by probe movement or organ displacement artifacts.
2Measurement precision
If conventional shear wave imaging techniques are used, then shear velocity can be estimated, but static deformations from probe movement and organ motion create artifacts that reduce signal quality
Solution Approach 1:
The filtering approach is made adaptive by defining the passband and stopband characteristics of the spatial filter based on the dynamic characteristics of the shear wave propagation. The filter dynamically adapts to the shear wave frequency and velocity to optimally separate the static deformation component from the shear propagation component in real-time.
Solution Approach 2:
A spatial filter acts as an intermediary between the raw movement signal and the final shear velocity estimation. This filter mediates by selectively attenuating spatial frequencies associated with static deformations while preserving spatial frequencies associated with shear wave propagation, thereby improving both signal quality and measurement reliability.
3Measurement precision
If a spatial filter is applied to remove static deformation components, then measurement accuracy improves, but the filter design requires careful selection of passband and stopband characteristics
Solution Approach 1:
The filter design parameters (passband and stopband characteristics) are defined as functions of the shear wave frequency and velocity. By parameterizing the filter characteristics based on measurable shear wave properties, the complex filter design is simplified and made adaptive to different tissue types and imaging conditions.
Solution Approach 2:
The system uses feedback from the measured shear wave characteristics to adjust the spatial filter parameters. The shear wave frequency and velocity estimated from the data are fed back into the filter design to optimize the passband and stopband characteristics, creating a self-adjusting system that reduces design complexity while maintaining high measurement precision.
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
The method effectively reduces the impact of static deformations, allowing for more accurate estimation of viscoelastic properties by filtering out the static-deformation component while preserving the shear-propagation component.
Implementation Method 1
a phase of filtering the images of movement to attenuate the static-deformation component
Implementation Method 2
detecting and recording reception signals received from the viscoelastic medium, each reception signal being associated with a respective acquisition signal
Data Source
AI summary
The present invention relates to a method for analysing a region of interest of a viscoelastic medium, the method including a step (200) of acquiring signals representative of the movement of at least one shear-propagation component and of a static-deformation component, and a processing step (300) for determining at least one property of the medium, the processing step comprising the following sub-steps: # determining images of the region of interest: # estimating images of movement by comparing images of the region of interest: # filtering the images of movement to attenuate the statis-deformation component; # determining a property of the medium from the filtered images of movement.