Self-Calibrating MRI Coil Array for Non-Cartesian k-Space
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing parallel acquisition methods in magnetic resonance tomography require significant additional measurement efforts for calibration, particularly with non-Cartesian k-space scanning, and cannot efficiently transfer reconstruction rules from Cartesian to non-Cartesian scanning trajectories.
Innovation Solution
A method using two-dimensional or three-dimensional acquisition coil arrays for undersampling k-space with basic partial trajectories, determining algebraic operators to synthesize unmeasured target points without explicit calibration measurements, and reconstructing images in three-dimensional space using these operators, allowing for efficient self-calibration and reduced measurement time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If parallel acquisition methods are used to reduce measurement time, then productivity is improved, but device complexity increases due to additional calibration measurements
Solution Approach 1:
The system performs self-calibration by determining algebraic operators directly from the undersampled k-space data without requiring separate calibration measurements. The coil sensitivity information is extracted automatically during the reconstruction process, making the system self-sufficient and eliminating the need for additional calibration equipment or procedures.
Solution Approach 2:
Coil sensitivity information is determined in advance during the reconstruction process before final image formation. The algebraic operators are pre-calculated from the undersampled data, preparing the system for efficient reconstruction without requiring subsequent calibration steps.
2Manufacturing precision
If additional calibration measurements are performed to improve image quality, then manufacturing precision is improved, but loss of time increases
Solution Approach 1:
The calibration process and image reconstruction process are merged into a single unified operation. The determination of coil sensitivity information and the reconstruction of images occur simultaneously using the same undersampled k-space data, eliminating the need for separate calibration measurements and reducing total measurement time.
Solution Approach 2:
The same undersampled k-space data serves multiple purposes: it is used both for determining coil sensitivity information and for reconstructing the final images. This multi-functional use of the data eliminates redundant measurements and optimizes the use of acquisition time.
3Adaptability or versatility
If non-Cartesian k-space scanning is used to improve imaging capability, then adaptability is improved, but difficulty of detecting and measuring increases
Solution Approach 1:
The method changes the mathematical parameters and transformation approaches used in reconstruction to accommodate non-Cartesian trajectories. By using algebraic operators and iterative reconstruction techniques, the system adapts to arbitrary k-space sampling patterns without requiring complex trajectory-specific processing for each case.
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 artifact-free image reconstruction without additional calibration measurements, significantly shortening the total measurement time and allowing for efficient image acquisition in non-Cartesian scanning by harmonizing k-space geometry with PPA reconstruction seeds.
Implementation Method 1
MRT is based on the physical phenomenon of nuclear magnetic resonance and has been successfully used as an imaging method for over 20 years in medicine and biophysics. In this examination modality the subject is exposed to a strong, constant magnetic field. The nuclear spins of the atoms in the subject, which were previously randomly oriented, thereby align. Radio-frequency energy can now excite these 'ordered' nuclear spins to a specific oscillation. In MRT, this oscillation generates the actual measurement signal which is acquired by means of suitable reception coils.
Implementation Method 2
Non-homogeneous magnetic fields generated by gradient coils follow the measurement subject to be spatially coded in all three spatial directions.
Data Source
AI summary
In a method as well as a magnetic resonance tomography apparatus for implementation of such a method for improved sensitivity-encoded magnetic resonance imaging using a two-dimensional or three-dimensional acquisition coil array, two-dimensional or three-dimensional undersampling of k-space is undertaken by measurement of a number N of basic partial trajectories τn in k-space that in their entirety form a geometric arrangement of source points, a number M of different operators Cm(Δkm) are determined, with each operator representing an algebraic transformation with which unmeasured target points at an interval Δkm from one of the measured source points are synthesized from a number of measured source points, the operators Cm(Δkm) are applied to at least one subset of the measured source points for at least partial completion of the magnetic resonance data set, and a largely artifact-free image is reconstructed in three-dimensional space on the basis of the measured source points and the synthesized data points.