MRI k-Space Calibration for Rotated Cartesian Scanning
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Solution Overview
Problem
Current magnetic resonance imaging techniques face challenges when combining accelerated imaging methods with recording techniques that alter the k-space coordinate system, leading to increased recording times, SAR burden, and image blurring due to the need for repeated reference data measurements.
Innovation Solution
A method where a calibration area of k-space is determined and scanned separately to generate a calibration data set, allowing derivation of reference data for each recording section without additional measurements, enabling accelerated imaging and improved image quality by reducing the need for time-consuming reference measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reference measurements are performed for each recording section when combining accelerated imaging with rotated Cartesian scanning, then reference data accuracy is maintained, but recording time increases significantly
Solution Approach 1:
The patent performs a preliminary calibration measurement that acquires reference data for all possible recording sections in advance. This preliminary action eliminates the need to repeat reference measurements for each subsequent recording section, thereby maintaining reference data accuracy while significantly reducing total recording time.
Solution Approach 2:
The calibration measurement serves multiple functions simultaneously: it acquires reference data for all possible recording sections, determines the coordinate system transformation, and prepares data for accelerated imaging. This multi-functionality eliminates redundant measurements and reduces overall recording time.
2Manufacturing precision
If multiple reference measurements are performed for different recording sections, then image quality is maintained, but SAR burden increases
Solution Approach 1:
The calibration measurement is performed once in advance to acquire all necessary reference data, eliminating the need for repeated reference measurements that would increase SAR burden. This preliminary action maintains image quality while reducing cumulative SAR exposure.
3Measurement precision
If multiple reference measurements are performed for different recording sections, then reference data accuracy is maintained, but the number of k-space lines to be scanned increases
Solution Approach 1:
The calibration measurement acquires reference data for all possible recording sections in a single preliminary scan, rather than requiring separate reference measurements for each recording section. This dramatically reduces the total number of k-space lines that must be scanned while maintaining reference data accuracy.
Solution Approach 2:
The single calibration measurement serves all recording sections universally, providing reference data for any possible rotation angle. This eliminates redundant scanning of the same or overlapping k-space regions multiple times, thereby improving scanning efficiency.
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 accelerates the recording process and enhances image quality by eliminating the need for individual reference measurements, allowing for faster data acquisition and increased resolution without extending echo time, thus reducing blurring and SAR burden.
Implementation Method 1
Magnetic resonance imaging is an established imaging technique in the medical field
Implementation Method 2
nuclear spins in multiple slices are excited within a repetition of the excitation pulse and the magnetic resonance signals from these slices are received (detected) simultaneously
Implementation Method 3
Cartesian scanning of k-space is carried out differently, by a rotation of gradient directions around the center of k-space
Data Source
AI summary
A magnetic resonance apparatus and method acquire magnetic resonance data with a recording technique in which the Cartesian scanning of k-space is carried out differently, by a rotation of gradient directions around the center of k-space, for different recording sections of a respective part of the magnetic resonance data, and this recording technique is combined with an accelerating imaging technique for which reference data completely describing a reference range around the center of k-space are used for each individual slice to be scanned. At the beginning of the recording, a calibration area of k-space, which includes all the reference ranges required in the course of recording, is determined and a calibration data set of k-space is recorded in a calibration measurement with complete, Cartesian scanning of the calibration area. Reference data for each recording section are determined from this calibration data set.