MRI Multi-Slice Imaging Prepulse Interference Control
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Solution Overview
Problem
In multi-slice magnetic resonance imaging (MRI) procedures, the influence of prepulses on MR signals collected at one stage can degrade image quality due to their impact on subsequent signal collection, depending on the slice collection order.
Innovation Solution
The MRI apparatus employs imaging control and processing circuitry to perform static magnetic field shimming, determining optimal center frequencies for RF pulses and prepulses, and a specific slice collection order to minimize interference between slices, ensuring that prepulses do not overlap with RF pulses applied to different slices during multi-slice imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multi-slice imaging is performed with prepulses for fat-suppression, then imaging capability is improved, but prepulse interference degrades image quality
Solution Approach 1:
The patent determines the center frequencies of RF pulses and prepulses based on static magnetic field distributions obtained from shimming imaging performed in advance. This preliminary frequency determination allows the system to configure pulse parameters before actual imaging, preventing frequency overlap and prepulse interference while maintaining fat-suppression capability
Solution Approach 2:
The patent applies different center frequencies to RF pulses and prepulses based on local magnetic field characteristics determined through shimming imaging. By tailoring the frequency parameters to local conditions in each slice, the system achieves fat-suppression without causing interference between prepulses and subsequent RF pulses
2Measurement precision
If static magnetic field shimming is performed, then frequency accuracy is improved, but imaging time is increased
Solution Approach 1:
The patent performs static magnetic field shimming imaging and determines center frequencies in advance before the actual multi-slice imaging sequence. By preparing the frequency configuration beforehand, the system achieves accurate frequency matching without adding time during the main imaging process
Solution Approach 2:
The shimming imaging process automatically determines the static magnetic field distribution and calculates appropriate center frequencies for both RF pulses and prepulses. This self-service approach eliminates the need for manual frequency adjustment and optimizes the timing of frequency determination within the imaging sequence
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 high-quality multi-slice imaging by preventing prepulse interference, maintaining image quality and enabling flexible adjustment of the slice collection order based on operator input or stored data.
Implementation Method 1
a magnetic resonance imaging apparatus that performs imaging on a subject by collecting magnetic resonance signals from the subject
Implementation Method 2
generates a plurality of static magnetic field distributions respectively corresponding to the slices based on the first magnetic resonance signal, determines a first center frequency of an RF pulse corresponding to each of the slices and a second center frequency of the prepulse based on the static magnetic field distribution
Data Source
AI summary
An MRI apparatus includes imaging control circuitry that performs shimming imaging for collecting a first MR signal, and multi-slice imaging for collecting a second MR signal along with radiation of a non-region-selective prepulse, and processing circuitry that generates static magnetic field distributions of the slices, determines a first center frequency of an RF pulse corresponding to each slice and a second center frequency of the prepulse based on the static magnetic field distribution, and determines an order of slices for collecting the second MR signal in accordance with the first and/or second center frequencies, wherein the imaging control circuitry performs the multi-slice imaging in accordance with the order and the first and second center frequencies.