Shear Mode Pressure-Activated Driver for MRE
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Solution Overview
Problem
Existing magnetic resonance elastography (MRE) drivers rely on mode conversion of longitudinal waves to produce shear waves, leading to complex wave patterns and phase errors that complicate the inversion process and introduce inaccuracies in stiffness estimation.
Innovation Solution
A pneumatic driver system that produces shear waves directly without mode conversion, comprising a remotely located pneumatic driver connected by a tube to a pressure-activated driver positioned on the subject, generating shear oscillatory forces through oscillations that apply pressure waves to the subject, thereby reducing complexity and errors in wave propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mode conversion of longitudinal waves is used to produce shear waves, then shear waves can be generated, but complex wave patterns and phase errors occur that complicate the inversion process and reduce measurement precision
Solution Approach 1:
The patent extracts and eliminates the mode conversion step from the wave generation process. Instead of converting longitudinal waves to shear waves through tissue interfaces, the system directly generates shear waves using a shear mode transducer that applies oscillatory shear stress to the tissue surface, thereby removing the source of complex wave patterns and phase errors
Solution Approach 2:
The patent inverts the traditional approach by not converting longitudinal waves to shear waves, but rather directly generating shear waves through a shear mode transducer. This reversal of the wave generation mechanism eliminates the mode conversion process and its associated problems with wave pattern complexity and phase errors
2Measurement precision
If a pressure-activated driver is positioned on the subject, then direct shear wave production is achieved, but the driver structure becomes more complex requiring base plate, driver plate, and tube assembly
Solution Approach 1:
The patent segments the driver into distinct functional components: a base plate for positioning, a driver plate for applying shear stress, and a tube for pneumatic actuation. This segmentation allows each component to perform its specific function efficiently while maintaining overall system manageability and reducing the complexity burden through modular design
Solution Approach 2:
The patent introduces a pneumatic tube as an intermediary element that transmits oscillatory pressure from a remote source to the driver plate. This intermediary allows the driver to be actuated without direct mechanical connection to the complex control system, simplifying the interface between the control mechanism and the tissue-contacting element
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 allows for the direct production of shear waves within the subject, reducing the complexity of the MRE inversion process and mitigating phase errors, resulting in more accurate mechanical property determination of tissues during MRI scans.
Implementation Method 1
A pneumatic driver located remotely from the MRI system is operable in response to an applied electrical current to oscillate
Implementation Method 2
Oscillations of the pneumatic driver produce a pressure wave in the tube that causes the driver plate in the pressure-activated driver to vibrate
Implementation Method 3
The driver plate rests against the subject of interest to apply a corresponding shear oscillatory force to the subject during the MRE examination
Data Source
AI summary
A magnetic resonance elastography (“MRE”) driver that can produce shear waves in a subject without relying on mode conversion of longitudinal waves is disclosed. More specifically, the MRE driver includes a pneumatic driver located remotely from a magnetic resonance imaging (“MRI”) system which is operable in response to an applied electrical current to oscillate, a pressure-activated driver that is positioned on a subject in the MRI system, and a tube that is in fluid communication, at one end, with the pneumatic driver. The pressure-activated driver includes a base plate and a driver plate having a region between them that receives the tube. Oscillations of the pneumatic driver produce a pressure wave in the tube that causes the driver plate to vibrate. The driver plate rests against the subject of interest to apply a corresponding shear oscillatory force to the subject during the MRE examination.