MRI-Xray Motion Compensation via X-ray Tracking
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Solution Overview
Problem
Magnetic resonance imaging (MRI) is susceptible to image quality reduction and artifacts due to subject movement during data acquisition, especially in medical imaging, as existing motion correction methods are inadequate for internal movements and require laborious marker attachment or are prone to local optimization issues.
Innovation Solution
A method using a combined magnetic resonance and X-ray device to acquire X-ray images for movement data, which is then used to adjust magnetic resonance data acquisition parameters and correct for movement by modifying phase information and coordinates, allowing for real-time motion compensation and improved image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If magnetic resonance imaging is performed with long acquisition time, then image quality can be improved through better signal averaging, but subject movement during acquisition causes image artifacts and quality reduction
Solution Approach 1:
The system performs preliminary action by acquiring X-ray images before and during the MRI acquisition to capture subject movement information in advance. These X-ray images are then used to calculate movement data that compensates for motion artifacts during the MRI reconstruction process, allowing the system to prepare correction data before the full MRI acquisition is complete.
Solution Approach 2:
The system implements feedback by continuously monitoring subject movement through X-ray imaging and using this information to adjust and correct the MRI data acquisition in real-time. The movement data derived from X-ray images feeds back into the MRI reconstruction process to compensate for motion artifacts, creating a closed-loop system that adapts to subject movement.
2Measurement precision
If optical markers are attached to track subject movement, then motion correction can be achieved, but the approach becomes laborious and cannot track internal movements
Solution Approach 1:
The system extracts movement information directly from the subject's internal anatomy using X-ray imaging, eliminating the need for external optical markers. By taking out the movement tracking function from external markers and embedding it within the subject's own anatomical structures visible on X-ray, the system achieves internal movement tracking without additional external equipment.
Solution Approach 2:
The X-ray imaging system serves multiple functions: it provides both diagnostic imaging and movement tracking simultaneously. The same X-ray apparatus used for medical imaging also captures subject movement during the MRI procedure, eliminating the need for separate marker-based tracking systems and reducing overall device complexity.
3Manufacturing precision
If iterative minimization of entropy is used to approximate movement from MRI data, then minor movements can be compensated, but larger movements cause the algorithm to get stuck at local optima
Solution Approach 1:
The system introduces X-ray images as an intermediary that provides direct measurement of subject movement. Instead of relying solely on indirect MRI data reconstruction to infer movement, the X-ray images serve as a mediator that directly captures anatomical position changes, providing reliable movement data even for large movements without algorithmic convergence issues.
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 effectively compensates for internal subject movements, reduces imaging artifacts, and enhances image quality by using X-ray data to adjust magnetic resonance data acquisition, particularly in medical imaging applications like heart and diaphragm imaging, and can be applied during or after data acquisition.
Implementation Method 1
several X-ray images are acquired in succession by a X-ray acquisition unit
Implementation Method 2
several data points representing a magnetic resonance signal strength for different phase encodings are acquired by a magnetic resonance acquisition unit
Data Source
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AI summary
Method for the acquisition and processing of measurement data by a combined magnetic resonance and X-ray device (1), wherein several X-ray images are acquired in succession by a X-ray acquisition unit (2) and processed to determine movement data describing a movement of a test subject or at least one region of the test subject during a given time interval, wherein several data points representing a magnetic resonance signal strength for different phase encodings are acquired by a magnetic resonance acquisition unit (3) during the time interval or an equivalent further time interval, in which the same movement pattern of the test subject or the region is expected, and wherein the data points are processed to generate at least one real space image as a function of the movement data and/or wherein at least one acquisition parameter used for the acquisition of at least one of the data points is adjusted as a function of the movement data.