Wireless MR tracking of interventional devices using phase-field dithering and projection reconstruction

Area of Science:

• Medical Imaging
• Interventional Radiology
• Biomedical Engineering

Background:

• Conventional interventional MRI (iMRI) devices are often invisible and can cause artifacts.
• Accurate device tracking is essential for safe and effective iMRI procedures.

Purpose of the Study:

• To present a robust method for wireless tracking and dynamic guidance of interventional devices using wirelessly connected resonant circuits (wRC).
• To enable real-time feedback and intuitive interaction during iMRI procedures.

Main Methods:

• Utilized weak, spatially-selective excitation pulses (0.3° flip angle) and a Hadamard multiplexed tracking scheme.
• Employed phase-field dithering for precise 3D position determination of wRC.
• Conducted RF induced heating experiments and simulated balloon angioplasties in phantoms and cadavers.

Main Results:

• Achieved device tip tracking with geometry updates in under 30ms.
• Phase-field dithering enhanced tracking robustness for small-diameter catheters (4-6 French).
• Reported a volume root mean square distance error of 2.81mm (±1.31mm) with no significant RF induced heating (<0.6°C).

Conclusions:

• The developed tip tracking approach offers a flexible, fast, and robust feedback loop for iMRI.
• Devices with wRC can be interchanged during procedures without altering the iMRI setup or pulse sequence.
• Current implementation tracks a single coil; further studies are needed for complex navigation before clinical application.