Multi-Slice MRI Gradient Moment Determination
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Solution Overview
Problem
Current methods for simultaneous multi-slice nuclear spin tomography face complexity and error-proneness in determining necessary gradient moments, especially for segmented recording methods with multiple excitations, due to laborious and complex calculations.
Innovation Solution
The method involves phase-encoding along the slice axis and combining it with incomplete sampling along the slice axis, allowing for a systematic determination of gradient moments by assigning pulse space coordinates to each point in the pulse space region, enabling flexible and universal use across different recording techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If segmented recording methods with multiple excitations are used for simultaneous multi-slice imaging, then imaging coverage and flexibility are improved, but the complexity and error-proneness of determining gradient moments increases
Solution Approach 1:
The pulse space is segmented into multiple regions, each assigned to different phase-encoded axes. This segmentation allows systematic determination of gradient moments for each region, reducing overall complexity while maintaining flexibility for segmented recording methods
Solution Approach 2:
A second pulse space dimension is assigned to a second phase-encoded axis corresponding to the slice axis, adding dimensional structure to the gradient moment determination process. This dimensional organization simplifies the calculation framework for multi-slice segmented imaging
2Loss of time
If incomplete sampling along the slice axis is implemented, then acquisition time is reduced, but sampling completeness and image quality may be compromised
Solution Approach 1:
Incomplete sampling along the slice axis is deliberately implemented by assigning only certain pulse space coordinates to the second phase-encoded axis. This partial sampling approach reduces acquisition time while the systematic assignment methodology ensures adequate image quality through controlled undersampling patterns
3Ease of operation
If a systematic assignment of pulse space coordinates is used, then ease of operation is improved, but device complexity increases due to additional processing requirements
Solution Approach 1:
The systematic assignment methodology creates a universal framework that handles both single-slice and multi-slice, segmented and non-segmented imaging through the same pulse space coordinate assignment rules. This universal approach simplifies operation while the processing complexity is managed through standardized algorithms
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 simplifies and reduces errors in determining gradient moments, making it feasible for segmented recording methods and multiple excitations, while allowing for flexible application across various image acquisition techniques.
Implementation Method 1
simultaneous multi-slice nuclear spin tomography
Implementation Method 2
magnetic resonance (MR) images
Data Source
AI summary
A flexibly and universally applicable method for simultaneous multi-slice nuclear spin tomography is provided. Thereby, a pulse space region to be sampled is specified by means of a processor, wherein a first pulse space dimension (ky) is assigned to a first phase-encoded axis and a second pulse space dimension (kz) is assigned to a second phase-encoded axis and the second phase-encoded axis corresponds to a slice axis. An undersampling scheme is specified by means of the processor, wherein along the second pulse space dimension (kz), an incomplete sampling is provided. Then, a magnetic resonance scan is carried out within the pulse space region to be sampled according to the undersampling scheme and according to respective phase-encodings of the first and second phase-encoded axis.