Local Nonlinear Tissue Elasticity Estimation via Acoustic Radiation Force
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Solution Overview
Problem
Current methods for estimating tissue nonlinearity parameters are limited by their reliance on global inverse problems that are computationally expensive and difficult to solve, and they fail to account for the nonlinear coupling between shear and compressive motions in ultrasound-based imaging modalities.
Innovation Solution
A method and system using acoustic radiation force (ARF) with amplitude-modulated ultrasound waves to locally determine tissue nonlinearity parameters by inducing shear waves and calculating normalized parameters under specific normalization conditions, allowing for the estimation of the nonlinearity coefficient without requiring global tissue characterization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If global inverse problems are used to estimate tissue nonlinearity parameters, then comprehensive tissue characterization is achieved, but computational complexity and difficulty increase significantly
Solution Approach 1:
The patent segments the global tissue characterization problem into local measurements at specific detection points. By using multiple detection points and measuring shear wave parameters locally, the method avoids solving a single complex global inverse problem while still achieving comprehensive tissue characterization through aggregation of local measurements.
Solution Approach 2:
The patent transforms the problem from estimating nonlinearity parameters directly through complex global inversion to measuring shear wave speed and attenuation parameters that can be obtained through simpler local measurements. This parameter transformation simplifies the computational burden while maintaining estimation accuracy.
2Ease of operation
If conventional ultrasound methods are used, then linear tissue properties are measured, but nonlinear coupling between shear and compressive motions is not accounted for
Solution Approach 1:
The patent uses acoustic radiation force to induce shear wave vibrations in the tissue, which naturally couple with compressive motions through nonlinear tissue mechanics. By measuring the characteristics of these coupled vibrations (shear wave speed and attenuation), the method captures nonlinear tissue properties without requiring complex measurement procedures.
Solution Approach 2:
The patent introduces shear wave propagation as an intermediary phenomenon that mediates between the applied acoustic radiation force and the tissue's nonlinear mechanical properties. By measuring shear wave characteristics, the method indirectly probes nonlinear tissue properties in a simplified manner compared to direct nonlinear measurement approaches.
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 accurate local estimation of tissue nonlinearity, facilitating differential cancer diagnosis by accounting for nonlinear tissue interactions and reducing the impact of ultrasound attenuation, thereby improving diagnostic precision and reducing computational complexity.
Implementation Method 1
an acoustic radiation force formed with irradiating the origin region with a first ultrasound wavefront generated by said ultrasound system
Implementation Method 2
detecting ultrasound energy reflected from at least two detection points of the subject by irradiating these at least two detection points with a second ultrasound wavefront
Data Source
AI summary
Ultrasound system and method configured to locally determine a parameter of nonlinear tissue elasticity by monitoring shear wave propagating through the tissue. The shear wave is caused by an acoustic radiation force (ARF) which is applied to the tissue by ultrasound irradiation locally, in a focal region of the ultrasound beam and which is a function of the intensity of ultrasound irradiation, its time rate, and the featured nonlinearity parameter. The irradiation does not involve a quasi-static compression of the tissue, thereby permitting local estimation of nonlinear tissue elasticity and circumventing the need to solve the global inverse problem.