Active microcoil tracking in the lungs using a semisolid rubber as signal source

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Interventional Radiology

Background:

• Accurate localization of medical devices in air-filled body cavities is challenging.
• Existing methods may lack precision or require complex setups.
• Active microcoils offer a potential solution for real-time device tracking.

Purpose of the Study:

• To develop and evaluate a novel method for localizing and tracking medical devices in air-filled body cavities.
• To utilize active microcoils with a biocompatible semisolid filling for signal generation.
• To assess the feasibility of the technique for in vivo applications.

Main Methods:

• Investigated T(1), T*(2), and spin density of semisolid materials to identify suitable candidates.
• Constructed a prototype catheter with a microcoil tip using identified latex material.
• Employed a dual-echo tracking pulse sequence with subtraction and dephasing gradients to suppress background signals.
• Implemented roadmapping reconstruction and real-time imaging sequences for visualization and tracking.

Main Results:

• Latex was identified as a suitable semisolid material for microcoil filling.
• The method achieved a tracking rate of up to 60 Hz with sub-2mm spatial resolution using roadmapping.
• Real-time tracking achieved an image update rate of 4 Hz.
• Successfully demonstrated in vivo catheter tracking in a pig's lung.

Conclusions:

• The proposed active microcoil method enables precise localization and tracking of medical devices in air-filled cavities.
• The technique effectively suppresses background signals and provides real-time visualization.
• This method holds promise for enhancing the safety and efficacy of minimally invasive procedures.