Wide Beam Contrast Imaging Using Pulse Inversion Wavelet Transform
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Solution Overview
Problem
Conventional ultrasound contrast imaging techniques face challenges in maintaining a high contrast-to-tissue ratio (CTR) due to high acoustic power and contrast agent concentration, which can be harmful, and struggle with low frame rates that lead to poor imaging quality and inaccurate extraction of perfusion time-intensity curves (TICs) due to tissue and organ movement.
Innovation Solution
A wide beam contrast imaging method using pulse inversion wavelet transform sum squared differences (PIWSSD) that reduces acoustic power and enhances CTR by constructing microbubble mother wavelets, processing RF signals with wavelet correlation analysis, and applying decorrelation thresholds to achieve accurate and rapid extraction of TIC tendencies through Detrended Fluctuation Analysis (DFA) fitting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional B-mode ultrasonography employs relatively higher acoustic power to obtain high resolved ultrasonic image and imaging depth, then image resolution and imaging depth are improved, but tissue damage and microbubble damage increase, decreasing the contrast-to-tissue ratio
Solution Approach 1:
The patent employs pulse inversion technology using periodic alternating polarity waves (0度和180度相位波) to image microbubbles. This periodic action allows the system to capture microbubble signals at different phases, enhancing contrast detection without requiring higher acoustic power, thus resolving the contradiction between image resolution and tissue/microbubble damage.
Solution Approach 2:
The patent changes the acoustic parameter from conventional B-mode to pulse inversion mode with alternating polarity. By transforming the imaging mechanism from direct amplitude detection to differential phase detection, the system achieves high contrast-to-tissue ratio at lower acoustic power levels, avoiding tissue and microbubble damage while maintaining image resolution.
2Area of stationary object
If conventional scanning mode scans line-by-line causing multiple times of damages to the microbubbles, then complete coverage of the imaging area is achieved, but the contrast agent concentration must be further enhanced to maintain relatively high CTR, potentially threatening human health
Solution Approach 1:
The patent merges multiple scanning lines into a single wide beam plane wave transmission. Instead of scanning line-by-line, the system transmits a broad plane wave that covers the entire imaging area simultaneously, reducing the number of transmissions from multiple line scans to a single or few plane wave transmissions. This significantly reduces cumulative microbubble damage while maintaining complete area coverage.
Solution Approach 2:
The patent uses periodic pulse inversion with alternating polarity (0度和180度相位交替) in plane wave transmission. This periodic action enables the system to extract microbubble contrast signals through differential processing of alternating phase waves, achieving high CTR with reduced acoustic power and fewer transmissions, thereby reducing microbubble damage and health risks.
3Use of energy by moving object
If low frame rate B-mode contrast imaging is used, then acoustic power can be reduced, but respiratory movement and organ involuntary peristalsis generate false movement tracks, affecting imaging quality and accurate extracting of TIC
Solution Approach 1:
The patent employs high frame rate plane wave imaging with periodic pulse inversion at alternating phases. This enables the system to capture rapid tissue and microbubble dynamics at high temporal resolution (high frame rate), freezing motion artifacts from respiratory movement and organ peristalsis. The high frame rate allows accurate extraction of time-intensity curves by capturing the true temporal dynamics of contrast agent perfusion.
Solution Approach 2:
The patent replaces conventional B-mode scanning mechanics with plane wave transmission and pulse inversion signal processing. This substitution enables high frame rate imaging without the mechanical constraints of line-by-line scanning, allowing the system to capture rapid physiological movements and accurately extract TIC information despite low acoustic power usage.
4Use of energy by moving object
If low frame rate imaging is used, then acoustic power consumption is reduced, but the performance in catching rapidly-moving organ is poor, resulting in absence of instantaneous movement information
Solution Approach 1:
The patent uses periodic pulse inversion with alternating polarity waves transmitted as plane waves at high frame rates. This periodic action enables the system to capture instantaneous movement information of rapidly moving organs by freezing motion at high temporal resolution, achieving both low acoustic power consumption and high speed performance.
Solution Approach 2:
The patent merges multiple scanning operations into a single plane wave transmission that covers the entire imaging area simultaneously. This merging enables high frame rate imaging at low acoustic power by eliminating the sequential line-by-line scanning process, allowing the system to capture instantaneous movement information without increasing overall power consumption.
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 method effectively increases CTR, reduces potential harm from high acoustic power, and provides accurate and rapid extraction of TIC tendencies, improving imaging quality and perfusion evaluation while reducing the impact of singular points and shortening processing time.
Implementation Method 1
the pulse inversion (PI) is the common manner for obtaining the relatively high signal-to-noise ratio (SNR) through the apparent echo differences caused by the non-linearity of the microbubbles and the linearity of the tissues
Implementation Method 2
processing the wide beam RF signals with phase 0/180 which are received by the ultrasound array transducers, with a wavelet correlation analysis based on the microbubble mother wavelets obtained in the step (1)
Implementation Method 3
The decorrelation is the manner for improving the CTR, by setting the decorrelation threshold based on the decorrelation difference of the contrast microbubbles and the surrounding tissues between the neighboring echo signals of the video frequency (VF) signals
Data Source
AI summary
A contrast imaging method based on a wide beam and a method for extracting a perfusion time-intensity curve (TIC) are provided to increase contrast-to-tissue ratio (CTR) through the contrast imaging method based on the wide beam via a pulse inversion microbubble wavelet transform sum squared differences decorrelation (PIWSSD). An auto adaptive analysis method about rapidly and accurately extracting a TIC tendency of the contrast imaging method based on the wide beam is also provided to overcome limitations of a decrease in the CTR of the contrast imaging based on the wide beam and a decrease in SCR of the perfusion TIC. The present invention plays an important role in effectively reducing an ultrasound contrast imaging acoustic power and a contrast microbubble perfusion concentration, reducing potential threat to human body, acquiring a contrast image with the high CTR, and accurately evaluating and diagnosing blood perfusion.