Elastography Probe Guidance Using Transient Pulse Propagation
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Solution Overview
Problem
Existing elastography devices face challenges in accurately positioning the probe due to difficulties in distinguishing between homogeneous and non-homogeneous tissue, leading to erroneous measurements, particularly when the probe is positioned near organs like the liver or lungs, which can create biased harmonic elastograms and inaccurate tissue stiffness estimations.
Innovation Solution
An elastography device that alternates between guidance and measurement modes, using transient, low-frequency probing pulses to assess propagation quality and homogeneity, providing real-time guidance by determining a propagation quality indicator based on echo signals, and delivering measurement pulses for accurate tissue stiffness measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If continuous periodic vibration is used for guidance, then tissue deformation tracking is possible, but shear and compression waves mix causing measurement errors
Solution Approach 1:
The patent applies periodic transient pulses instead of continuous vibration. Each pulse is separated by a time interval that allows shear waves to dissipate before the next pulse arrives, preventing wave mixing while maintaining periodic sampling for accurate measurement
Solution Approach 2:
The patent uses short-duration pulses that rapidly deliver mechanical energy and then stop, skipping the continuous vibration phase. This allows the system to rush through the measurement window before compression waves interfere, capturing pure shear wave propagation data
2Measurement precision
If high amplitude pulses are used for measurement, then signal detection is improved, but subject discomfort increases
Solution Approach 1:
The patent applies partial action by using multiple low-amplitude pulses instead of a single high-amplitude pulse. Each pulse delivers sufficient energy for measurement while remaining below the discomfort threshold, and multiple pulses are averaged to achieve the signal quality of a high-amplitude pulse
Solution Approach 2:
The patent performs preliminary guidance measurements using low-amplitude continuous vibration to establish proper probe positioning and tissue contact before transitioning to the actual measurement mode, ensuring optimal conditions are met before applying higher amplitude pulses
3Productivity
If probe positioning is not verified, then measurement speed is maintained, but positioning accuracy deteriorates
Solution Approach 1:
The patent implements a preliminary guidance phase before the actual measurement. During this phase, continuous low-amplitude vibration is applied and tissue deformation is tracked to verify probe positioning and tissue homogeneity, ensuring accurate positioning before committing to the final measurement
Solution Approach 2:
The system continuously monitors tissue deformation during the guidance phase and uses this feedback to determine when proper positioning is achieved. The transition from guidance to measurement mode is triggered by feedback indicators confirming adequate probe placement and tissue characteristics
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
The device offers improved positioning accuracy and reduced discomfort by using transient pulses, minimizing ultrasound exposure, and enhancing the precision of tissue stiffness estimation through real-time guidance and reduced mixing of shear and compression waves.
Implementation Method 1
a low frequency vibrator, to deliver low frequency mechanical pulses to the body of a subject... to track how the low frequency mechanical pulses travel in the body
Implementation Method 2
at least one ultrasound emitter and one ultrasound receiver arranged to emit ultrasound pulses and to receive corresponding echoes to track how the low frequency mechanical pulses travel
Data Source
AI summary
An elastography device includes a probe that includes a protruding part to be applied against the body of a subject, a low frequency vibrator arranged to move the protruding part, at least one ultrasound emitter and one ultrasound receiver; and an electronic unit. The electronic unit is adapted to alternatively control the elastography device so that it operates (a) in a guidance mode to determine whether the probe is correctly positioned in front of a region of the body to be probed to carry out a measurement of a mechanical property of the probed region and (b) in a measurement. In the guidance mode, the vibrator delivers a plurality of successive probing pulses (PRB), each being a transient, low frequency mechanical pulse, and the electronic unit determines a propagation quality indicator (Q) representative of an aptitude of the probed region to transmit the probing pulse.