ARFI Noise Removal via Spatial Pulse Segmentation
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Solution Overview
Problem
ARFI ultrasonic systems are sensitive to background noises such as system electronic noise and patient movement, particularly cardiac and respiratory movement, due to the low amplitude of shear waves, which affects the accuracy of shear wave displacement estimation, and existing solutions like increasing wave beam transmission voltage or duration exceed FDA limitations.
Innovation Solution
The method involves transmitting push pulses along a push pulse vector and a first group of focus track pulses at locations far away from the vector to capture noise, then subtracting noise signals from signals collected at locations adjacent to the push pulse vector to isolate shear waves, thereby eliminating background noise without increasing pulse duration or voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wave beam transmission voltage or duration is increased to reduce sensitivity to background noise, then measurement reliability is improved, but sound output power exceeds FDA limitations
Solution Approach 1:
The patent segments the ultrasonic measurement process into two distinct phases: a push pulse phase for generating shear waves and a track pulse phase for measuring tissue displacement. By separating the high-power push pulse from the low-power measurement pulses and timing them differently, the system achieves reliable measurements without continuously exceeding power limits
Solution Approach 2:
The patent employs periodic alternating transmission of push pulses and track pulses at different time intervals. Push pulses are transmitted periodically to generate shear waves, followed by periodic track pulses to measure displacement. This periodic action allows the system to operate within FDA power limits while maintaining measurement reliability through repeated measurements
2Strength
If push pulse strength is increased to improve shear wave generation, then shear wave amplitude is improved, but sound output power exceeds FDA limitations
Solution Approach 1:
The patent applies preliminary action by transmitting the high-power push pulse before the measurement process. The push pulse pre-generates shear waves in the tissue, creating a sustained mechanical impulse response that can be measured over an extended period with low-power track pulses, thereby achieving good shear wave amplitude without continuous high power output
3Measurement precision
If measurement time is extended to improve signal-to-noise ratio, then measurement precision is improved, but productivity is reduced
Solution Approach 1:
The patent maintains continuity of useful action by continuously transmitting track pulses throughout the measurement window after the push pulse. This continuous low-power tracking allows the system to accumulate signal data over time for improved precision while keeping the overall measurement time relatively short, thus maintaining productivity
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 effectively reduces sound output power within FDA limits, enhances the reliability of shear wave measurements, and improves the accuracy of tissue elasticity characterization by isolating shear wave signals from noise, providing clearer mechanical impulse responses.
Implementation Method 1
the force required to push the tissues downwards can be produced by radiation pressure from ultrasonic pulses
Implementation Method 2
conventional ultrasounds are used to track shear wave displacement of tissues
Data Source
AI summary
A method for eliminating background noises in shear waves and the respective ultrasonic imaging system, the method includes: transmitting a push pulse along a push pulse vector; transmitting a first group of focus track pulses at a first group of a plurality of locations far away from the push pulse vector; receiving a first group of focus echo signals in response to the first group of focus track pulses; and processing the first group of focus echo signals to determine a first group of tissue displacement information varying with time.