MRI RF Pulse Level Determination via Region Segmentation
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Solution Overview
Problem
Magnetic Resonance Imaging (MRI) apparatuses face challenges in accurately determining the RF pulse levels for 90° and 180° pulses, particularly when imaging regions with varying signal intensities, leading to suboptimal MR signal acquisition due to the influence of high signal areas like muscle and fat.
Innovation Solution
The MRI apparatus includes processing circuitry that selects a specific area within the field of view based on signal distribution, allowing for the determination of RF pulse levels tailored to the region of interest, reducing the impact of high signal intensity areas and improving signal acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the RF level is determined based on the average value of all MR signals in the entire FOV, then the determination process is simple and fast, but the accuracy of RF level determination deteriorates when the region of interest has low signal intensity due to influence from high signal areas
Solution Approach 1:
The patent divides the field of view (FOV) into multiple regions and selectively determines the RF level based on signals from a specific region of interest rather than using all signals from the entire FOV. This segmentation allows accurate RF level determination for the target area while avoiding contamination from high-signal regions, resolving the contradiction between measurement precision and processing complexity.
Solution Approach 2:
The patent applies local quality by determining RF levels specifically tailored to the signal characteristics of the region of interest rather than using a uniform approach for the entire FOV. This allows the system to optimize signal acquisition for the specific anatomical area being imaged, improving measurement precision without requiring excessive computational complexity.
2Reliability
If the RF level is determined based on all MR signals in the FOV including high signal areas, then the determination process is straightforward, but the MR signal intensity of the region of interest deteriorates due to dominant influence from high signal areas like muscle and fat
Solution Approach 1:
The patent segments the FOV into multiple regions and selectively processes signals only from the region of interest, excluding high-signal areas that would otherwise dominate the average calculation. This ensures reliable MR signal acquisition for the target area while maintaining manageable system complexity through focused processing.
Solution Approach 2:
The patent extracts and isolates the signal from the specific region of interest, removing the influence of high-signal areas such as muscle and fat that would otherwise contaminate the RF level determination. This extraction approach improves signal acquisition reliability by concentrating on the relevant anatomical region.
3Measurement precision
If multiple spin echo sequences are executed with different RF levels to determine the optimal RF level, then the RF level determination becomes more accurate, but the pre-scan time increases
Solution Approach 1:
The patent reduces pre-scan time by segmenting the FOV and executing spin echo sequences only for the region of interest rather than the entire FOV. This localized approach maintains measurement precision for RF level determination while significantly reducing the number of sequences required and thus the total pre-scan time.
Solution Approach 2:
The patent applies partial action by performing RF level determination only on the necessary region of interest rather than the entire FOV. This partial processing approach achieves sufficient measurement precision for the target area while reducing the overall time investment required for the pre-scan process.
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 the accurate determination of RF pulse levels specific to the region of interest, enhancing MR signal intensity and image quality by reducing the influence of high signal areas, thus improving diagnostic imaging.
Implementation Method 1
excites atomic nuclear spins of an imaging region placed in the static magnetic field with high frequency pulses of Larmor frequency
Implementation Method 2
high frequency pulses of Larmor frequency
Implementation Method 3
the MRI apparatus receives magnetic resonance signals, that is, MR signals generated from the imaging region with the excitation by a reception coil
Data Source
AI summary
A magnetic resonance imaging apparatus according to an embodiment includes a transmission coil and processing circuitry. The transmission coil is configured to apply a high frequency magnetic field to an object. The processing circuitry is configured to: derive, based on at least one of an imaging region and the body shape data of the object, a specific area in a field of view (FOV); and determine, based on a signal within the specific area, an output power level of a high frequency pulse signal supplied to the transmission coil.