Self-Navigating MRI K-Space Trajectory for Motion Correction
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Solution Overview
Problem
Patient motion during MRI scans often causes image artifacts, and existing motion artifact reduction techniques either require additional scan time, complexity, or can only detect motion without estimating it effectively.
Innovation Solution
A self-navigating technique using overlapping winders in k-space for reading out magnetic fields, allowing for motion detection and correction with minimal scan time penalty, utilizing a modified Butterfly pulse sequence for Cartesian acquisitions, which can measure and correct translational motion at sub-pixel accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional motion artifact reduction techniques are used, then motion correction can be achieved, but scan time increases or complexity increases
Solution Approach 1:
The patent combines motion estimation and image reconstruction into a single integrated process. The self-navigating technique merges the k-space trajectory design with motion correction, allowing both functions to be performed simultaneously without requiring separate scan segments or additional processing steps that would increase scan time.
Solution Approach 2:
The patent implements self-navigating motion correction where the MRI scan data itself contains the navigation information needed for motion estimation. The overlapping winders in k-space automatically provide motion data without requiring external navigators or additional scan sequences, enabling the system to correct its own motion artifacts without external intervention or time penalty.
2Measurement precision
If additional navigators or motion estimation sequences are added, then motion detection improves, but device complexity increases
Solution Approach 1:
The patent makes the k-space trajectory serve multiple functions simultaneously. The same winders used for image data acquisition also serve as navigation signals for motion estimation. By designing the readout trajectory to overlap with itself in a specific pattern, the system achieves both imaging and motion detection with a single pulse sequence, eliminating the need for separate navigator echoes or additional sequences.
Solution Approach 2:
The patent segments the k-space readout into overlapping winders that can be independently processed for motion estimation. By dividing the continuous k-space trajectory into segments that overlap by a certain amount, the system creates discrete navigation data points from which motion can be calculated, while maintaining the simplicity of the overall pulse sequence structure.
3Productivity
If self-navigating technique with overlapping winders is used, then motion correction with minimal scan time penalty is achieved, but measurement precision requirements increase
Solution Approach 1:
The patent uses partial overlap of winders in k-space to achieve motion estimation. Instead of requiring complete coverage or redundant sampling, the method uses the overlapping portions of the winders to extract motion information. This partial action approach reduces the computational burden and maintains precision while improving scan efficiency, as only the overlapping regions need to be processed for motion estimation rather than the entire k-space trajectory.
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 detection and correction of motion in real-time with negligible scan time overhead, suitable for various clinical applications, including high-resolution scans and cardiac imaging, by providing accurate motion information for data acceptance or rejection.
Implementation Method 1
Magnetic resonance imaging (MRI) requires placing an object to be imaged in a static magnetic field (B0), exciting nuclear spins in the object with a RF magnetic field (B1), and then detecting signals emitted by the excited spins as they precess within the magnetic field (B0)
Implementation Method 2
Through the use of magnetic gradient and phase encoding of the excited magnetization, detected signals can be spatially localized in three dimensions
Data Source
AI summary
A method for magnetic resonance imaging (MRI) is provided. A magnetic resonance excitation is provided. A magnetic field is read out through k-space using winders, wherein some of the winders overlap for a length of the winders. Readout data from overlapping lengths of winders is used to estimate motion. The readout may use a two dimensional discrete Fourier transform acquisition.