Magnetic Resonance Scan Data Correction Using Segmented Echo Planar Imaging
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Solution Overview
Problem
Conventional magnetic resonance imaging methods, such as PLACE imaging, require significant time differences between repeated acquisitions of correction data sets, which can be affected by patient movement, leading to reduced quality of correction information and increased sensitivity to movement artifacts.
Innovation Solution
The method involves acquiring phase-shifted correction data sets in sections of the correction volume immediately after each other, rather than acquiring the entire correction volume at once, to reduce the interval between repeated acquisitions and minimize the impact of patient movement, using echo planar imaging sequences to obtain multiple correction data sets from distinct sub-volumes with minimal time gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the entire correction volume is acquired in repeated acquisitions with a repetition time interval, then the correction data sets can be obtained for correction of magnetic resonance scan data, but the time difference between repeated acquisitions of the same slice leads to increased sensitivity to patient movement and reduced quality of correction information
Solution Approach 1:
The correction volume is divided into multiple correction sub-volumes, which are acquired in a sequential manner during the same repetition time interval. This segmentation allows the acquisition process to be completed within a single TR, eliminating the time difference problem that occurs when acquiring the entire correction volume in repeated acquisitions.
2Reliability
If the correction volume is divided into multiple correction sub-volumes acquired sequentially within the same repetition time interval, then the sensitivity to patient movement is reduced and correction quality is improved, but the acquisition process becomes more complex
Solution Approach 1:
The correction volume is divided into multiple correction sub-volumes that can be acquired sequentially within the same repetition time interval. This segmentation enables the system to obtain correction data from different spatial locations without requiring multiple TR intervals, thereby improving reliability while managing complexity through structured organization.
Solution Approach 2:
The gradient switching operations are dynamically adjusted to enable sequential acquisition of different correction sub-volumes within the same repetition time interval. The phase coding direction gradients are modified to target specific sub-volumes in sequence, allowing flexible and adaptive acquisition that improves consistency without excessive complexity.
3Productivity
If multiple phase-coded echoes are generated to fill the raw data matrix in k-space, then the correction data sets can be obtained efficiently, but the gradient switching operations increase the complexity of the pulse sequence
Solution Approach 1:
Multiple phase-coded echoes are generated using periodic gradient switching operations that cycle through different phase encoding steps. This periodic action efficiently fills the k-space matrix with correction data from multiple sub-volumes, maintaining high productivity while organizing the complexity into a systematic, repeatable pattern.
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 improved correction of magnetic resonance scan data by reducing the interval between repeated acquisitions, enhancing the consistency and quality of correction information, and reducing the sensitivity to patient movement, resulting in more accurate and efficient image correction.
Implementation Method 1
the nuclear spins of specific atoms, excited in a resonant manner by these radio-frequency pulses
Implementation Method 2
gradient switchings are activated by the operation of gradient coils
Implementation Method 3
multiple phase-coded echoes are successively generated by gradient refocusing in order to fill a raw data matrix in a memory, called k-space
Data Source
AI summary
In a method and magnetic resonance (MR) apparatus for correcting MR scan data, an MR scanner is operated to acquire first and second correction data sets respectively from first and second sub-volumes of a correction volume, by successive executions of an echo planar imaging sequence. The MR scanner is also operated to acquire third and fourth correction data sets respectively from third and fourth correction sub-volumes, also by successive executions of the echo planar imaging sequence. A first item of correction information is ascertained from the first and second correction data sets, and a second item of correction information is ascertained from the third and fourth correction data sets. The first and second items of correction information are then used to correct scan data, also acquired with the MR scanner.