Retrospective External Motion Calibration Using Distributed MRI K-Space Data
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Solution Overview
Problem
Existing MRI motion correction techniques require additional scan time for calibration and may not capture the full range of patient motion, especially when relying on external motion sensors like optical or RF-based methods, which need training phases that assume motion parameters remain valid throughout the examination.
Innovation Solution
Acquire motion calibration k-space data packets between MRI scans using a distributed fashion, combining them to estimate motion states and calibrate the external motion signal retrospectively, without requiring patient cooperation or additional scan time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a training phase is executed to calibrate external motion sensors, then motion calibration accuracy is improved, but examination time increases
Solution Approach 1:
The patent acquires motion calibration data packets at multiple time points throughout the examination in advance, rather than performing a separate training phase before the examination. This preliminary distribution of calibration acquisitions across the examination timeline allows motion calibration to be performed without extending total examination time, while still capturing the full range of patient motion.
2Difficulty of detecting and measuring
If external motion sensors are used for motion correction, then motion detection capability is improved, but reliability of motion parameters decreases due to limited motion range capture
Solution Approach 1:
The patent employs periodic acquisition of motion calibration data packets at multiple predetermined time points throughout the examination. This periodic sampling ensures that the full range of patient motion is captured across different phases of the examination, making the calibration model valid for the entire duration and improving reliability of motion parameters.
Solution Approach 2:
By distributing calibration acquisitions throughout the examination in advance, the system captures motion data across the complete range of patient motion before final reconstruction. This preliminary capture of diverse motion states ensures that external motion sensors record the full motion range, validating motion parameters for retrospective correction.
3Device complexity
If motion calibration data is acquired in a single phase before examination, then calibration process is simplified, but adaptability to actual patient motion decreases
Solution Approach 1:
The patent segments the motion calibration process into multiple distributed acquisitions throughout the examination rather than a single bulk calibration phase. Each acquisition captures motion characteristics specific to that time period, and the combined data provides comprehensive coverage of patient motion ranges, enhancing calibration model adaptability while maintaining procedural simplicity.
Data Source
AI summary
Systems and methods for retrospectively calibrating an external motion signal in parallel to a magnetic resonance imaging examination of a subject, wherein the magnetic resonance imaging examination includes several magnetic resonance imaging scans. The method includes acquiring a plurality of motion calibration k-space data packets using a magnetic resonance imaging protocol in between the magnetic resonance imaging scans, combining the k-space data packets acquired across the magnetic resonance imaging examination (and applying an optimization algorithm to the combined k-space data packets in order to estimate motion states of the subject during acquisition of the k-space data packets. The method further includes estimating a calibration motion model from the motion states and the external motion signal acquired simultaneously with the data packets, wherein the calibration motion model maps the external motion signal to a corresponding motion state.