MRI Orientation Tracking Device for Motion Correction
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Solution Overview
Problem
Patient movement during MRI scans leads to inaccuracies in image clarity due to involuntary motion, which is challenging to avoid, especially in longer scans or for patients with conditions like Parkinson's disease, limiting the achievable image resolution.
Innovation Solution
An orientation tracking device equipped with a memory for storing magnetic and gravitational reference data, accelerometers, magnetometers, and a processor that determines orientation by comparing measured vectors with stored data, and optionally includes a gyroscope for filtering spurious readings, feeding back acceleration and gyroscope measurements to the scanner for motion correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If MRI scanning is performed with high resolution capability, then image clarity is improved, but patient movement becomes a limiting factor that degrades image quality
Solution Approach 1:
The system performs preliminary action by tracking patient orientation and predicting future motion states before they occur. The processor continuously receives accelerometer and magnetometer data, determines current orientation, predicts future orientation states, and communicates these predictions to the MRI scanner in advance, allowing the scanner to prepare for and compensate against upcoming motion artifacts.
Solution Approach 2:
The system implements feedback by continuously monitoring patient movement through accelerometers and magnetometers, processing this data to determine orientation changes, and communicating the determined and predicted orientation information back to the MRI scanner. This closed-loop feedback enables real-time motion compensation during the scanning process.
2Manufacturing precision
If patient movement is detected and corrected in real-time, then image quality is improved, but device complexity increases due to multiple sensors and processing requirements
Solution Approach 1:
The orientation tracking device implements multi-functionality by integrating multiple sensor types (accelerometers for linear acceleration, magnetometers for magnetic field orientation, and gyroscopes for rotational motion) into a single device that performs both motion detection and orientation determination. This universal device replaces what would otherwise require separate systems, managing complexity through functional integration.
Solution Approach 2:
The system merges multiple sensing functions into a unified orientation tracking device that combines accelerometers, magnetometers, and gyroscopes. The processor integrates data from all these sensors to comprehensively determine three-dimensional orientation, combining multiple measurement modalities into a single coordinated system that manages complexity through unified processing.
3Measurement precision
If orientation tracking device is attached to patient for motion correction, then movement detection accuracy is improved, but patient comfort and ease of operation deteriorates
Solution Approach 1:
The orientation tracking device implements segmentation by dividing the measurement function into multiple independent sensor components (accelerometers for linear motion, magnetometers for magnetic orientation, gyroscopes for rotational motion). Each sensor type is optimized for specific measurement aspects, allowing the system to achieve comprehensive motion detection accuracy while keeping individual sensor units small and manageable for patient attachment.
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
The device accurately tracks and corrects for patient movement in real-time, improving image quality by mitigating the effects of motion, particularly in high-resolution MRI scans, and is compatible with MRI environments without the need for scanner-specific calibration.
Implementation Method 1
receiving from the magnetometer a measurement of a magnetic field vector in a co-ordinate frame of the orientation tracking device, within the magnetic imaging scanner
Implementation Method 2
receiving from the accelerometer a measurement of an acceleration vector in the orientation tracking device's co-ordinate frame
Implementation Method 3
receiving from the accelerometer a measurement of an acceleration vector
Implementation Method 4
The device may include at least one gyroscope also connected to the processor, so that the processor additionally uses measurements received from the gyroscope to determine orientation of the device
Data Source
AI summary
An orientation tracking device includes a memory for storing data including magnetic reference data relating to the direction of a static magnetic field of a magnetic imaging scanner in a selected principle co-ordinate frame and earth gravitational reference data relating to the direction of the gravitational field of the earth in the principle co-ordinate frame. The device also includes an accelerometer, magnetometer and communication module. A processor is adapted for receiving from the magnetometer measured magnetic field vector and from the accelerometer a measured acceleration vector. These vectors are in a co-ordinate frame of the orientation tracking device, within the magnetic imaging scanner in which the orientation tracking device is placed in use. The processor then determines the orientation of the device with respect to the principle co-ordinate frame by comparing the measured vectors from the accelerometer and magnetometer with the stored gravitational reference data and magnetic reference data respectively.