Magnetic Resonance Imaging Multi-Coil Signal Separation
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Solution Overview
Problem
Current Magnetic Resonance Spectroscopic Imaging (MRSI) techniques face challenges in simultaneously obtaining images of multiple substances with different chemical shifts, such as water and metabolite images, without extending measurement time, due to the need to suppress water signals for metabolite detection and correct eddy current-induced distortions.
Innovation Solution
A magnetic resonance imaging apparatus with multiple receiver RF coils that apply pre-pulses to shift signals, allowing for simultaneous measurement and separation of images using sensitivity maps, and correcting residual signals to obtain images of multiple substances without increasing measurement time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If water signals are suppressed to detect metabolite signals, then metabolite detection capability is improved, but water signal information is lost
Solution Approach 1:
The patent segments the signal detection process by using multiple receiver RF coils with different resonance frequencies. One coil is tuned to receive water signals while another is tuned for metabolite signals. This frequency-based segmentation allows simultaneous acquisition of both water and metabolite signals without interference, resolving the contradiction between suppressing water signals for metabolite detection and preserving water signal information.
Solution Approach 2:
The patent implements multi-functionality by enabling the MR imaging system to simultaneously perform multiple functions: water signal acquisition, metabolite signal acquisition, and eddy current correction. The multiple receiver RF coils allow the system to handle different signal types in parallel, making the system universal for both metabolite detection and water signal preservation.
2Measurement precision
If multiple images of different substances are obtained separately, then measurement completeness is improved, but measurement time is extended
Solution Approach 1:
The patent merges the acquisition of multiple substance images into a single measurement process. By using multiple receiver RF coils tuned to different resonance frequencies, the system simultaneously acquires water images and metabolite images in one scan, rather than requiring separate measurements. This combining approach maintains measurement completeness while significantly reducing total measurement time.
Solution Approach 2:
The patent applies preliminary action by pre-tuning multiple receiver RF coils to different resonance frequencies before the actual imaging measurement. This preliminary configuration allows the system to be ready for simultaneous multi-substance detection from the start of the measurement process, eliminating the need for sequential measurements and reducing overall time requirements.
3Manufacturing precision
If eddy current correction is performed using water signals, then image quality is improved, but water signals must be preserved
Solution Approach 1:
The patent merges the purposes of eddy current correction and water signal preservation by simultaneously acquiring both water and metabolite signals using multiple receiver RF coils. The water signals obtained from coils tuned to water resonance frequencies serve dual purposes: they provide the necessary information for eddy current correction while also preserving complete water signal data for subsequent analysis, eliminating the need to choose between correction and preservation.
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
Enables the simultaneous acquisition of images from multiple substances with different chemical shifts, such as water and metabolite images, without prolonging measurement time, improving diagnostic capabilities in metabolic disorders like cancer.
Implementation Method 1
irradiating a radio frequency magnetic field of a specific frequency on an object of measurement placed in a static magnetic field to induce magnetic resonance phenomenon
Implementation Method 2
separating magnetic resonance signals for every molecule on the basis of difference in resonance frequency (chemical shift) caused by difference of chemical bonds in the molecules (metabolites)
Implementation Method 3
applying a phase encoding gradient magnetic field for adding positional information to the magnetic resonance signals
Data Source
AI summary
Images of two or more kinds of substances showing different chemical shifts, such as water image and metabolite image, are obtained without extending measurement time. For example, images of two or more kinds of desired substances showing different chemical shifts, such as water image and metabolite image, are obtained by one time of execution of an imaging sequence. In this execution, a pre-pulse is applied so that signals of the substances to be separated shift on the image, and magnetic resonance signals are received with receiver RF coils in a number not smaller than the number of types of the substances to be separated. An image reconstructed from the magnetic resonance signals is separated into images of the individual substances using sensitivity maps of the receiver RF coils. Then, correction is performed for returning the shifted image to the original position. Further, residual signals induced by errors generated in the measurement and the separation processing are eliminated by using spectroscopic images obtained after the separation.