Crawling Wave Shear Velocity Imaging via Autocorrelation

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Solution Overview

Problem

Sonoelastographic imaging techniques have not been effectively applied to heterogeneous biomaterials for estimating shear velocities using interfering shear waves, known as crawling waves.

Innovation Solution

A novel real-time sonoelastographic technique that estimates local shear velocities from crawling wave images using one-dimensional or two-dimensional autocorrelation-based methods, allowing for the visualization and spatial mapping of shear velocity distributions, which are proportional to the shear modulus, enabling the production of quantitative tissue elasticity images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If 1D autocorrelation-based technique is used for shear velocity estimation, then computational simplicity is improved, but measurement precision deteriorates due to increased noise artifacts

Engineering Contradiction:

Improvecomputational simplicityVSAvoidnoise artifact level

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent transitions from one-dimensional autocorrelation analysis to two-dimensional autocorrelation analysis by incorporating both temporal and spatial dimensions. This dimensional expansion allows the system to distinguish between noise and actual shear wave signals more effectively, reducing noise artifacts while maintaining computational feasibility through efficient 2D signal processing algorithms.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Measurement precision

If 2D autocorrelation-based technique is used for shear velocity estimation, then measurement precision is improved by minimizing noise artifacts, but device complexity increases due to higher computational requirements

Engineering Contradiction:

Improvenoise artifact levelVSAvoidcomputational complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the shear wave analysis into distinct spatial and temporal components that can be processed independently through autocorrelation. By dividing the complex 2D analysis into manageable one-dimensional autocorrelation operations along different axes, the system achieves high measurement precision while keeping computational complexity tractable through modular processing.

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If crawling waves are used for shear velocity imaging in heterogeneous biomaterials, then adaptability is improved for tissue elasticity imaging, but difficulty of detecting and measuring increases due to complex interference patterns

Engineering Contradiction:

Improvetissue elasticity imaging capabilityVSAvoidshear velocity measurement difficulty

Core Design Contradiction:

Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent introduces autocorrelation analysis as an intermediary mathematical operation that simplifies the detection of crawling wave interference patterns. By computing the autocorrelation of the ultrasonic signal, the system transforms complex interference patterns into measurable phase shifts, making shear velocity detection in heterogeneous biomaterials feasible while maintaining adaptability for tissue elasticity imaging.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 real-time visualization and estimation of shear velocity distributions in heterogeneous biomaterials, improving lesion contrast and detection, and muscle tissue characterization by minimizing noise artifacts and providing enhanced computational performance.

Implementation Method 1

interfering shear waves to produce crawling waves

Methodology Applied

Scientific EffectInterference: Interference

Implementation Method 2

Two or more (preferably two) vibration sources are utilized to excite shear wave propagation and to generate shear wave interference patterns

Methodology Applied

Scientific EffectMechanical vibration: Vibration

Implementation Method 3

estimates the amplitude response of tissues under harmonic mechanical excitation using ultrasonic Doppler techniques

Methodology Applied

Scientific EffectDoppler effect: Doppler Effect

Implementation Method 4

phase derivatives estimated using either one-dimensional (1D) or two-dimensional (2D) autocorrelation-based techniques

Methodology Applied

Scientific EffectAutocorrelation:

Implementation Method 5

using an acoustic radiation force on each side of the region of interest to generate the interference patterns

Methodology Applied

Scientific EffectAcoustic radiation pressure: Acoustic Radiation Pressure

Data Source

PatentUS8267865B2Sonoelastographic shear velocity imaging using crawling wave excitation

Publication Date: 2012.09.18 UNIVERSITY OF ROCHESTER

AI summary

Vibration sources are applied to a body or other object to image a region of interest. The mechanical vibrations introduced by the sources interfere in the region of interest to produce a crawling wave, which is detected by an ultrasound probe A relationship between crawling wave phase derivatives and local shear wave velocity is derived with phase derivatives estimated using either one-dimensional (1D) or two-dimensional (2D) autocorrelation-based techniques to image the region of interest.