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Omnidirectional Monolithic Marker for Intra-Operative MR-Based Positional Sensing in Closed MRI
IEEE Transactions on Medical Imaging
|August 30, 2023
Summary
We developed a new inductively coupled radio frequency (ICRF) marker for enhanced magnetic resonance (MR) imaging positional tracking. This small, robust marker provides high-contrast, real-time 3D tracking regardless of orientation, improving clinical diagnosis and interventions.
Area of Science:
- Medical Imaging
- Biomedical Engineering
- Radio Frequency Engineering
Background:
- Magnetic Resonance Imaging (MRI) offers excellent soft-tissue contrast but lacks precise real-time positional tracking capabilities.
- Current tracking methods often struggle with signal degradation due to varying orientations and limited real-time feedback.
- Robust, wireless tracking solutions are crucial for advancing minimally invasive interventions and clinical diagnostics within MRI environments.
Purpose of the Study:
- To design and validate a novel Inductively Coupled Radio Frequency (ICRF) marker for improved magnetic resonance (MR)-based positional tracking.
- To enhance tracking signal robustness across all scanning orientations in quadrature-excited closed MRI.
- To enable automatic, real-time, and orientation-independent 3D tracking for clinical applications.
Main Methods:
- The marker utilizes three curved resonant circuits, each a planar spiral inductor with parallel plate capacitors on flexible printed circuit board (FPC).
- These circuits are monolithically fabricated and bent into a cylindrical structure to enclose the signal source.
- Performance was validated using a 1.5 T MRI scanner, assessing tracking accuracy and contrast under various rotational conditions.
Main Results:
- The ICRF marker consistently appeared as a high positive contrast spot under 360° rotations across three axes.
- Accurate localization was achieved with a maximum error of 0.56 mm within a 56 mm displacement from the isocenter.
- A low inherent standard deviation of 0.1 mm was observed, demonstrating high precision.
Conclusions:
- The developed ICRF marker significantly enhances MR-based positional tracking by providing a high-contrast, orientation-independent signal.
- Its small form-factor and robust performance facilitate automatic and real-time 3D tracking, crucial for interventional procedures and diagnostics.
- This technology promises to improve the safety and efficacy of image-guided interventions and clinical diagnosis in MRI.
