Ultrasonic Contrast Agent Imaging with Multi-Pulse Transmit Schemes
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Solution Overview
Problem
Conventional ultrasound contrast agents with thin, flexible shells face limitations in fragility, blood circulation time, multi-functionality, and drug loading capacity, and existing imaging techniques struggle to effectively image microbubbles above their resonance frequencies or with thicker shells.
Innovation Solution
A method involving the transmission of at least two ultrasound pulses along a radial image line, where one or more pulses induce physical movement or alter acoustic scattering properties, allowing for the combination of received signals to suppress tissue signals and enhance contrast agent imaging, particularly suitable for microbubbles with thicker shells and imaging frequencies significantly above resonance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional thin-shelled microbubbles are used for contrast imaging, then adequate contrast agent specificity can be obtained at low transmit pressures, but the microbubbles have limitations in fragility, blood circulation time, multi-functionality and drug loading capacity
Solution Approach 1:
The patent changes the physical parameters of the microbubble shell by transitioning from thin-shelled to thick-shelled microbubbles. This parameter change in shell thickness fundamentally alters the mechanical properties, providing improved fragility resistance and extended circulation time while maintaining contrast imaging capability through adapted pulse sequences
Solution Approach 2:
The patent employs dynamic pulse sequences that adapt to the different mechanical properties of thick-shelled microbubbles. By using multiple pulses with varying amplitudes and frequencies, the system dynamically exploits the nonlinear scattering behavior of thick-shelled microbubbles to maintain contrast specificity despite the structural changes
2Reliability
If imaging frequency is well above the bubble resonance frequency, then microbubbles can be imaged with reduced fragility, but existing imaging techniques struggle to effectively image microbubbles at these frequencies
Solution Approach 1:
The patent utilizes mechanical vibration principles by employing pulse sequences that excite resonant and non-resonant oscillations of thick-shelled microbubbles at frequencies above the resonance frequency. The multiple pulses with varying characteristics induce controlled vibrations that produce detectable nonlinear scattering signals
Solution Approach 2:
The patent applies periodic action through structured pulse sequences consisting of multiple transmitted pulses at different amplitudes and frequencies. This periodic excitation pattern enables the system to capture the nonlinear scattering response of thick-shelled microbubbles over time, improving detection effectiveness at frequencies above resonance
3Device complexity
If single pulse imaging is used, then the imaging process is simple, but adequate contrast agent signal detection is difficult due to tissue signal interference
Solution Approach 1:
The patent segments the imaging process into multiple distinct pulse transmission steps, each with specific amplitude and frequency characteristics. By dividing the imaging sequence into multiple pulses with different parameters, the system can separately analyze the nonlinear scattering response at each stage, thereby improving contrast detection while managing complexity through structured segmentation
Solution Approach 2:
The patent merges multiple signal measurements from different pulse transmissions to form the final contrast image. By combining information from multiple pulses with varying characteristics, the system enhances the contrast signal-to-tissue signal ratio through signal processing techniques that integrate the segmented measurements
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 robust imaging of ultrasound contrast agents by increasing the Contrast Signal to Noise Ratio and Contrast Signal to Tissue Ratio, allowing for more effective detection and imaging of microbubbles with reduced fragility and thicker shells, while avoiding destruction and improving drug delivery capabilities.
Implementation Method 1
at least one of said transmitted pulses induces a physical movement and/or at least transiently alters the acoustic scattering properties of the contrast agent
Implementation Method 2
Scattering from the microbubble is resonant through an interaction between the co-oscillating fluid mass around the bubble and the bubble compression elasticity
Implementation Method 3
The local nonlinear scattering from conventional ultrasound contrast agents is typically much larger than from soft tissues
Data Source
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AI summary
A method for detection and imaging of ultrasound contrast agents using multi-pulse transmit schemes, is described. The method is based on transmitting at least two pulses along each radial image line, where the purpose is to introduce a physical movement or a change in ultrasound scattering properties for the contrast agent. The image reconstruction is based on combining the received echoes resulting from at least two transmit pulses for suppression of tissue signal and detection and imaging of contrast agent signal.