Interleaved Motion Encoding for Efficient 3D Magnetic Resonance Elastography
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current volumetric 3D Magnetic Resonance Elastography (MRE) sequences are inefficient due to 2D slice acquisitions that miss out on higher SNR afforded by 3D acquisitions, and existing 3D techniques require substantial increases in TR and acquisition of multiple wave offsets, leading to inefficiencies.
Innovation Solution
A method and device for MRE that utilize a periodical vibration signal with a sampling period comprising a natural number of vibration periods plus a fixed delay, applying three motion encoding gradients and a reference scan within each sampling period, synchronized with the vibration signal to efficiently acquire 3D data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If 2D slice acquisitions are used for 3D MRE, then device complexity is reduced, but signal-to-noise ratio (SNR) deteriorates
Solution Approach 1:
The patent transitions from 2D slice acquisitions to a true 3D volumetric acquisition scheme by applying motion encoding gradients in all three spatial dimensions (x, y, z) simultaneously. This dimensional expansion enables coherent summation of signal across the entire volume, dramatically improving SNR while maintaining manageable device complexity through systematic gradient application.
2Measurement precision
If multiple wave offsets and substantial TR increases are used in existing 3D techniques, then measurement precision improves, but acquisition time increases
Solution Approach 1:
The patent implements continuous sampling of the vibration signal throughout the 3D acquisition process, with motion encoding gradients applied in each sampling period without interruption. This continuous measurement approach captures the propagating shear waves efficiently, achieving high measurement precision while minimizing acquisition time by eliminating gaps between measurements.
Solution Approach 2:
The patent utilizes periodic vibration excitation at a defined frequency (e.g., 60 Hz) and samples the signal at synchronized intervals. By applying motion encoding gradients at specific phases of the periodic vibration cycle and using Fourier transformation to isolate the fundamental frequency component, the method achieves precise biomechanical property estimation within a single breath-hold period.
3Measurement precision
If motion encoding gradients are applied in each sampling period, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent divides the 3D motion encoding process into three separate gradient applications along orthogonal axes (x, y, z directions). Each gradient application encodes motion along one dimension, and the combined effect captures the full 3D displacement field. This segmentation simplifies the overall system complexity by breaking down the complex 3D measurement into manageable sequential steps while maintaining high measurement precision.
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 a more efficient 3D MRE acquisition scheme that minimizes total acquisition time, reduces motion-related artifacts, and provides reliable stiffness and viscosity evaluations, enabling simultaneous assessment of liver fibrosis and inflammation in a single breath-hold.
Implementation Method 1
providing a periodical vibration signal for exciting mechanical vibrations with a vibration period
Implementation Method 2
Magnetic Resonance Elastography by direct visualization of propagating acoustic strain waves
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Magnetic Resonance Elastography (MRE) shall be performed more efficient. Therefore, there is proposed a method including the steps of providing a periodical vibration signal (11) for exciting mechanical vibrations within an object (8) to be examined with a vibration period, characterized by - sampling the vibration signal (11) with a sampling period (wp1, wp2, wp3, wp4), the sampling period (wp1, wp2, wp3, wp4) corresponding to a natural number including zero of vibration periods plus a fixed time delay (13), - the fixed time delay multiplied with a sampling number is equal to the vibration period, the sampling number being a natural number greater than two, - three motion encoding gradients (MEGx, MEGy, MEGz) are performed for magnetic resonance acquisition in each sampling period (wp1, wp2, wp3, wp4).