Towards Tracking of Deep Brain Stimulation Electrodes Using an Integrated Magnetometer

Electromagnetic Tracking System for Position and Orientation Detection of Deep Brain Stimulation Electrodes During Surgery

This paper describes a 3D electromagnetic tracking (EMT) system, based on quasi-static magnetic fields and a sub-millimeter 3D magnetometer, providing complete localization - both spatial and angular positions - during surgical procedures. By integrating miniaturized sensors into surgical tools, such as deep brain stimulation (DBS) electrodes, this tracking system offers complementary or alternative solutions for X-ray imaging. Each spatial position in the measurement volume (MV) is uniquely encoded by a vector of four magnetic field amplitudes using the multilateration principle. The orientation is derived from the three orthogonal components associated with this vector. The field generator (FG) was manufactured on printed circuit boards ensuring high reproducibility and accurate magnetic fields. Position localization was evaluated using a custom magnetic field camera placed at various positions in the MV while the orientation was evaluating using a stereotactic system used in DBS surgery. Finally, DBS implantations were simulated to conclude on the validity of the tracking system for DBS surgery. The system achieved spatial and angular errors of 1.72 mm and 0.89° within a MV of 15 × 15 × 15 cm3 located at 18 cm from the FG and an update rate of the position of 0.4 Hz. Better performances - mean spatial and angular errors of 0.87 mm and 0.52° - were achieved when simulating DBS implantations. With its large distance to the FG, this quasi-static EMT system is particularly well-suited for DBS surgery, offering regular feedback to neurosurgeons. The tracking system could also be adapted to other functional neurosurgeries.

Deep Brain Stimulation: Emerging Tools for Simulation, Data Analysis, and Visualization

Deep brain stimulation (DBS) is a well-established neurosurgical procedure for movement disorders that is also being explored for treatment-resistant psychiatric conditions. This review highlights important consideration for DBS simulation and data analysis. The literature on DBS has expanded considerably in recent years, and this article aims to identify important trends in the field. During DBS planning, surgery, and follow up sessions, several large data sets are created for each patient, and it becomes clear that any group analysis of such data is a big data analysis problem and has to be handled with care. The aim of this review is to provide an update and overview from a neuroengineering perspective of the current DBS techniques, technical aids, and emerging tools with the focus on patient-specific electric field (EF) simulations, group analysis, and visualization in the DBS domain. Examples are given from the state-of-the-art literature including our own research. This work reviews different analysis methods for EF simulations, tractography, deep brain anatomical templates, and group analysis. Our analysis highlights that group analysis in DBS is a complex multi-level problem and selected parameters will highly influence the result. DBS analysis can only provide clinically relevant information if the EF simulations, tractography results, and derived brain atlases are based on as much patient-specific data as possible. A trend in DBS research is creation of more advanced and intuitive visualization of the complex analysis results suitable for the clinical environment.