Echo-Planar Spectroscopic Imaging Stepped Gradient Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current Echo-Planar Spectroscopic Imaging (EPSI) techniques are limited by low spectral bandwidth, which is insufficient for high field strengths, high spatial resolutions, or metabolites with large chemical shifts, making them inadequate for many clinical applications.
Innovation Solution
The system and method employ a readout segmentation technique by using stepped encoding gradients in both the readout and phase-encoding directions, allowing for the random distribution of sampled and unsampled segments in the k-space, thereby increasing spectral bandwidth and reducing scan time while improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional EPSI techniques are used, then the method is simple to implement, but the spectral bandwidth is limited and insufficient for high field strengths and high spatial resolutions
Solution Approach 1:
The k-space data acquisition is segmented into multiple segments along the readout direction, with each segment acquired using a different readout gradient moment. This segmentation allows the spectral bandwidth to be increased by distributing the sampling across multiple gradient steps, thereby resolving the contradiction between spectral bandwidth and acquisition complexity.
Solution Approach 2:
The patent introduces an additional dimension to the traditional EPSI approach by applying gradient moments not only in the phase-encoding direction but also in the readout direction. This dimensional extension enables spectral encoding along both directions, significantly increasing the effective spectral bandwidth without proportionally increasing overall acquisition complexity.
2Productivity
If traditional EPSI with fixed readout gradient is used, then the acquisition is straightforward, but the spectral bandwidth remains low and scan time is excessive
Solution Approach 1:
The readout gradient moment is made dynamic by varying it across multiple segments rather than keeping it fixed. Each segment uses a different readout gradient moment, allowing the system to adaptively encode spectral information at different rates. This dynamic approach increases spectral bandwidth while maintaining efficient scan times.
Solution Approach 2:
The patent changes the readout gradient moment parameter across different segments of k-space acquisition. By systematically varying this parameter, the method achieves higher spectral bandwidth encoding capability while maintaining a manageable number of acquisitions, thus improving scan efficiency.
3Measurement precision
If spectral bandwidth is increased to accommodate high field strengths, then measurement precision improves, but data acquisition complexity and scan time increase
Solution Approach 1:
By segmenting the k-space acquisition into multiple segments with different readout gradient moments, the patent efficiently packs more spectral encoding into the available scan time. This segmentation allows high spectral bandwidth to be achieved without requiring a proportional increase in total acquisition time.
Solution Approach 2:
The method maintains continuous useful action by acquiring data from multiple segments in a systematic sequence, ensuring that each segment contributes to the overall spectral encoding. This continuous acquisition approach maximizes the use of scan time for productive data collection, reducing overall scan time while maintaining high spectral bandwidth.
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 significantly enhances spectral bandwidth, enabling higher spatial and spectral resolutions, and extends the applicability of EPSI to various clinical and pre-clinical imaging, including high-field strengths and low-field systems, by decoupling echo spacing from spatial resolution and exploiting data sparsity.
Implementation Method 1
Magnetic Resonance Spectroscopic Imaging (MRSI)... combines temporal data sampling with MR imaging techniques to generate localized spectra
Implementation Method 2
spatially-varying metabolite concentrations... spectra can then be used to provide important clinical information
Data Source
AI summary
The invention relates to a system for performing echo-planar spectroscopic imaging. The system comprises an acquisition unit for acquiring magnetic resonance data, wherein the acquisition unit is adapted to use a first encoding gradient in a readout direction and a second encoding gradient in a phase-encoding direction, wherein the first encoding gradient and the second encoding gradient are stepped. The system further comprises a reconstruction unit for reconstructing a magnetic resonance image based on the acquired magnetic resonance data.