Computed Ultrasound Tomography Echo Mode Sound Speed Imaging
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Solution Overview
Problem
Conventional ultrasound technologies face challenges in achieving high spatial resolution and contrast for sound speed imaging, particularly in tissues where transmission is obstructed by bones, and existing methods for pulse-echo ultrasound provide low resolution and are limited in clinical applicability.
Innovation Solution
A method involving the transmission and detection of ultrasound pulses in multiple directions to reconstruct local echo phase shifts, allowing for the determination of sound speed with high contrast and spatial resolution using a handheld probe, enabling real-time tomographic imaging of sound speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If transmission ultrasound tomography is used to image sound speed, then spatial resolution and contrast are improved, but the method is limited to acoustically transparent tissues and requires dedicated equipment
Solution Approach 1:
The patent inverts the traditional transmission mode by using pulse-echo mode, where ultrasound is transmitted and received from the same side. This allows imaging of sound speed in tissues that are not acoustically transparent, such as those with bone obstructions, thereby expanding clinical applicability while maintaining measurement precision through phase shift analysis of echo signals
Solution Approach 2:
The patent makes the sound speed imaging method universal by enabling it to work with conventional pulse-echo ultrasound equipment already widely used in clinics, rather than requiring dedicated transmission tomography equipment. This multi-functionality allows the same ultrasound system to perform both conventional imaging and sound speed mapping
2Adaptability or versatility
If conventional pulse-echo ultrasound is used for sound speed imaging, then clinical applicability is improved, but spatial resolution and contrast are degraded
Solution Approach 1:
The patent changes the measurement parameter from amplitude or time-of-flight to phase shift of the echo signal. By analyzing the phase shift as a function of transmission angle, the method achieves high sound speed contrast (better than 1%) and spatial resolution (1 mm) using conventional pulse-echo equipment, resolving the contradiction between clinical applicability and measurement precision
3Measurement precision
If beam-tracking method is used to measure sound speed, then spatial resolution is improved to 10 mm, but the setup complexity and rigidity increase
Solution Approach 1:
The patent employs a single ultrasound probe that both transmits and receives signals, making the system self-sufficient without requiring separate transmission and reception equipment. The probe independently performs scanning and signal detection, eliminating the need for complex rigid setups with multiple synchronized components while achieving 1 mm resolution through phase shift analysis
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 sound speed imaging with better than 1% contrast and 1 mm resolution, suitable for diagnostic imaging, and is applicable to tissues inaccessible to traditional transmission-based methods, expanding the clinical utility of ultrasound.
Implementation Method 1
the time of flight of acoustic power coupled from one into the other beam allowed the measurement of sound speed along the propagation path
Implementation Method 2
so that said first ultrasound pulse is backscattered in said object towards said ultrasound probe in the form of first ultrasound pulse echoes
Data Source
AI summary
The invention relates to a method for determining and particularly imaging sound speed in an object by means of pulse-echo ultrasound, comprising the steps of: transmitting by means of an ultrasound probe (1) at least a first ultrasound pulse (10) in a first direction (.phi..sub.0) and a second ultrasound pulse (20) in a different second direction (.phi.) into an object (O) to be imaged, so that said first ultrasound pulse (10) is backscattered in said object towards said ultrasound probe in the form of first ultrasound pulse echoes (11), and so that said second ultrasound pulse (20) is backscattered in said object towards said ultrasound probe in the form of second ultrasound pulse echoes (21), detecting said backscattered first ultrasound pulse echoes (11) and said backscattered second ultrasound pulse echoes (21) with said ultrasound probe (1), reconstructing from said detected backscattered first ultrasound pulse echoes (11) a first image of first local echoes (5) and from said detected backscattered second ultrasound pulse echoes (21) a second image of second local echoes (7), wherein said images lie in an image plane spanned by said directions (.phi..sub.0, .phi.), determining from said reconstructed images the respective resulting local echo phase shift .DELTA..tau.(x, z, .phi., .phi..sub.0) corresponding to the difference in echo time (t) between the respective first local echo and the corresponding second local echo relative to the case of an assumed constant sound speed, and determining the local sound speed c(x, z) in said object for at least a region of said image plane in said object from said local echo phase shift .DELTA..tau.(x, z, .phi., .phi..sub.0). Further, the invention relates to a corresponding computer program and a system.