MRI Center Frequency Calibration via Dual-Gradient Dynamic Shift
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Calibrating the center frequency of magnetic resonance (MR) systems is challenging, especially when the carrying bed is constantly moving, as traditional pre-scanning methods require precise initial positioning and stability, making it difficult to achieve accurate calibration.
Innovation Solution
A method and apparatus that apply a first and second set of gradient fields in different directions to calculate and correct the center frequency by generating and comparing images received by an RF coil, allowing for accurate calibration even with a moving bed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pre-scanning method is used to calibrate center frequency, then calibration accuracy is improved, but the requirement for static bed positioning increases
Solution Approach 1:
The patent transforms the static pre-scanning method into a dynamic calibration approach that functions during actual imaging when the bed is moving. The calibration process adapts to the moving bed condition by performing frequency calibration in-situ during image acquisition, eliminating the need for separate static positioning steps.
Solution Approach 2:
The patent performs center frequency calibration as a preliminary step integrated into the imaging workflow. By incorporating calibration into the imaging process itself rather than requiring a separate pre-scanning step, the system achieves accurate frequency calibration before actual diagnostic imaging begins, without requiring the bed to be stationary.
2Measurement precision
If pre-scanning is performed for center frequency calibration, then calibration accuracy is improved, but imaging time increases
Solution Approach 1:
The patent merges the center frequency calibration process with the imaging acquisition process. By combining these two previously separate operations into a single integrated workflow, the system achieves accurate frequency calibration without requiring additional dedicated calibration time, as both calibration and imaging data are collected during the same scanning period.
Solution Approach 2:
The patent maintains continuous useful action by performing calibration and imaging simultaneously without interruption. The calibration process occurs continuously during the imaging sequence, ensuring that the center frequency is accurately determined while the imaging process proceeds uninterrupted, thereby eliminating time loss associated with separate calibration steps.
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 precise calibration of the center frequency in MR systems, ensuring accurate MR image alignment without the need for static pre-scanning, allowing for real-time correction during imaging.
Implementation Method 1
If a linear gradient magnetic field is added into the main magnetic field, the precession frequencies of proton groups in various parts of a subject being detected may be distinguished from each other due to different magnetic induction intensities
Implementation Method 2
A radio frequency (RF) pulse may excite the protons to generate resonance. When a precession frequency of a proton is the same as a center frequency of the RF pulse, energy exchange can occur, and a proton with a low energy obtains energy to enter into a high energy state, i.e., generating nuclear magnetic resonance (NMR)
Data Source
AI summary
Methods and apparatuses for calibrating a center frequency of MR and an MRI system are disclosed herein. An exemplary method comprises applying a first set of gradient fields, receiving data information acquired by an RF coil and generating a first image; applying a second set of gradient fields in directions different than those of the first set of gradient fields, receiving data information acquired by the RF coil and generating a second image; calculating a shift of the center frequency based on the first image and the second image; and correcting the center frequency based on the shift of the center frequency.