Phase Velocity Imaging for Soft Tissue Lesion Characterization
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Solution Overview
Problem
Existing methods for measuring soft tissue mechanical properties, such as shear wave elastography, face challenges in accurately resolving small inclusions and providing high contrast images due to limited spatial extent and assumptions about tissue homogeneity, leading to difficulties in imaging inhomogeneities and characterizing lesions effectively.
Innovation Solution
A method for generating phase velocity images from mechanical wave motion data using an ultrasound system, which involves acquiring data over a range of frequency values, reconstructing phase velocity images, and adjusting acquisition parameters to achieve an optimal bandwidth, enabling the creation of high-resolution images of phase velocity and viscoelastic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional shear wave elastography methods are used with limited spatial extent, then measurement simplicity is maintained, but resolution and contrast for small inclusions deteriorate
Solution Approach 1:
The patent transitions from limited spatial extent measurements to full-field imaging by extending the measurement domain across the entire tissue region. This dimensional extension enables simultaneous measurement of multiple points, improving resolution and contrast for small inclusions while maintaining practical usability through automated processing.
Solution Approach 2:
The patent uses phase velocity as a proxy or copy of the mechanical properties to infer tissue characteristics. By measuring phase velocity distribution across the field, the system indirectly characterizes stiffness and viscoelastic properties without requiring direct force application at each measurement point, thus improving resolution while managing complexity.
2Measurement precision
If assumptions of tissue homogeneity are made, then analysis simplicity is maintained, but accuracy in characterizing inhomogeneities and lesions deteriorates
Solution Approach 1:
The patent applies local quality analysis by examining phase velocity variations at different spatial locations independently. Instead of assuming uniform tissue properties, the method identifies local anomalies and inhomogeneities by comparing phase velocity measurements across the field, enabling accurate lesion characterization while using localized analysis to manage computational complexity.
Solution Approach 2:
The patent changes the measurement parameter from simple time-of-flight to phase velocity, which provides more sensitive information about tissue mechanical properties. This parameter change enables detection of subtle inhomogeneities and improves accuracy in characterizing lesions, with the added complexity handled through established signal processing techniques.
3Measurement precision
If time-domain methods are used for shear wave velocity estimation, then measurement simplicity is maintained, but measurement precision for phase velocity deteriorates
Solution Approach 1:
The patent substitutes time-domain mechanical measurement methods with frequency-domain phase analysis. By analyzing the phase component of the complex wave number obtained from Fourier transformation, the system achieves more precise phase velocity measurements. This substitution replaces direct time-of-flight measurement with a more sophisticated but computationally manageable frequency-domain approach.
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 the accurate depiction of inclusions smaller than 5 mm in diameter with improved contrast and resolution, effectively characterizing soft tissues and lesions by optimizing acquisition parameters for enhanced phase velocity measurements.
Implementation Method 1
These methods use acoustic radiation force to generate shear waves
Implementation Method 2
ultrasound techniques to measure the shear wave motion
Implementation Method 3
frequency-domain assessment of shear wave velocity has been performed with phase gradient or Fourier transform-based methods
Implementation Method 4
phase gradient or Fourier transform-based methods
Implementation Method 5
These methods have been used to estimate phase velocity dispersion due to material viscoelasticity
Data Source
AI summary
Described here are systems and methods for phase velocity imaging using an imaging system, such as an ultrasound system, an optical imaging system (e.g., an optical coherence tomography system), or a magnetic resonance imaging system. In general, systems and methods for constructing phase velocity images (e.g., 2D images, 3D images) from propagating mechanical wave motion data are described. The systems and methods described in the present disclosure operate in the frequency domain and can be implemented using a single frequency or a band of selected frequencies. If there are multiple mechanical wave sources within the field-of-view, directional filtering may be performed to separate mechanical waves propagating in different directions. The reconstructions described below can be performed for each of these directionally filtered components.