Ultrasound Sound Speed Imaging via Sub-Aperture Beamforming
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Solution Overview
Problem
Current ultrasound imaging methods for determining the speed of sound in tissue are inefficient, requiring multiple transmissions and resulting in a worse signal-to-noise ratio and sensitivity to background motion, especially when using pulse-echo systems.
Innovation Solution
The method employs different receive apertures of a transducer array to beamform acoustic echoes from a single transmission, calculating the speed of sound by estimating relative axial displacements between these apertures, which allows for faster and more accurate measurement with improved signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple transmissions from different angles are used to estimate compressional sound speed, then the sound speed can be calculated, but the process causes delay and becomes sensitive to background motion
Solution Approach 1:
The patent segments the receive aperture into multiple sub-apertures (first sub-aperture, second sub-aperture, etc.) that can independently beamform echoes from a single transmission. This segmentation allows parallel processing of different spatial regions, eliminating the need for sequential multi-angle transmissions while maintaining the capability to estimate sound speed through comparing axial displacements between sub-aperture images.
2Measurement precision
If multiple transmissions from different angles are used to estimate compressional sound speed, then the sound speed can be calculated, but the process becomes sensitive to background motion
Solution Approach 1:
The patent performs preliminary beamforming with multiple sub-apertures from a single transmission before any motion can occur. By obtaining all necessary sub-aperture images simultaneously from one transmission event, the method eliminates temporal gaps between acquisitions, making the measurement invariant to background motion that would affect sequential multi-transmission approaches.
3Ease of operation
If plane waves are used for transmission, then the process is simplified, but the signal-to-noise ratio becomes worse
Solution Approach 1:
The patent applies local quality by using different receive sub-apertures with specific geometric configurations optimized for their respective spatial regions. Each sub-aperture is positioned and sized to capture echoes from specific angular ranges, allowing the system to maintain simple plane wave transmission while achieving improved signal-to-noise ratio through localized receive beamforming that maximizes signal capture from different directions.
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 enables quick and accurate estimation of sound speed in tissue, reducing the need for multiple transmissions, minimizing motion artifacts, and providing a higher signal-to-noise ratio, making it diagnostically and prognostically useful for characterizing tissue and potentially identifying pathologies like fatty liver disease.
Implementation Method 1
A transducer array of elements of an ultrasound scanner transmits acoustic energy into tissue of a patient
Implementation Method 2
At least first and second sub-apertures of the transducer array receive acoustic echoes responsive to the transmitting
Implementation Method 3
For different locations, axial displacements of signals from the received acoustic echoes of the first sub-aperture relative to signals from the received acoustic echoes of the second sub-aperture are estimated
Data Source
AI summary
For sound speed imaging, different receive apertures are used instead of multiple transmissions from different angles. Acoustic echoes from a same transmission are receive beamformed with different apertures of the transducer array. The axial shift between the beamformed signals from the different apertures is used to solve for the speed of sound at one or more locations. The resulting measure of the speed of sound is displayed as the speed of sound in the tissue and may be diagnostically or prognostically useful.