MaDoPO: Magnetic Detection of Positions and Orientations of Segmented Deep-Brain Stimulation Electrodes: A Radiation-Free Method Based on Magnetoencephalography

Detection of deep brain stimulation lead position and orientation in patients using magnetoencephalography

OBJECTIVE

Deep brain stimulation (DBS) programming in patients with directional DBS requires precise lead position and orientation knowledge. Current computed tomography (CT)-based methods expose patients to radiation. This study investigates a non-radiation-based magnetic detection approach using magnetoencephalography (MEG) in four Parkinson's disease patients.

METHODS

MEG recordings were performed under omnidirectional and directional electrode configurations. Three patients were measured with individualized head-casts to minimize head movement. Magnetic detection was applied to determine DBS lead's position and orientation, compared with those derived from postoperative CT imaging.

RESULTS

Conventional MEG recordings without head-casts achieved lead position and orientation accuracies of up to 17.3 mm and 24.1°. The use of head-casts improved accuracies to 5.8 ± 1.3 mm and 8.8 ± 2.2° at best. Higher mean errors indicate the presence of systematic biases, primarily caused by the MEG system's limited spatial precision. Reduced error variability demonstrates potential for 1-2 mm localization and 2-4° orientation accuracy.

CONCLUSIONS

While magnetic lead position detection is inferior to established approaches, DBS lead orientation could be determined with sufficient accuracy for potential clinical use. Advances in MEG technology may offer improvements in spatial precision and detection accuracy.

SIGNIFICANCE

This method may serve as a radiation-free alternative to imaging-based approaches.

Detailed Images of Deep Brain Stimulation Leads Using Micro-CT

INTRODUCTION

One of the challenges in directional deep brain stimulation (DBS) is to determine the orientation of implanted electrodes relative to targeted regions. Post-operative images must be aligned with a model of the implanted lead, usually a computer-based model provided by the manufacturer. This paper shows that models can alternatively be obtained by capturing images of individual leads using micro-CT, a high-resolution CT technique. Contrary to computer-aided design models, lead models generated this way provide realistic X-ray contrast and finer details.

METHODS

We scanned DBS leads from various vendors using a Bruker SkyScan 1276 micro-CT system. To reduce beam-hardening artefacts, samples were scanned at maximum X-ray tube voltage (100 kV) and with copper filtering. Images were made publicly available for download and 3D visualisation.

CONCLUSION

Detailed images of single DBS leads can be generated using standard micro-CT systems. Their use as reference models could improve lead orientation algorithms, in particular those dedicated to X-ray modalities. Furthermore, the possibility to share models online could broaden access for clinical research.

Advancements in non-invasive microwave brain stimulation: A comprehensive survey

This survey provides a comprehensive insight into the world of non-invasive brain stimulation and focuses on the evolving landscape of deep brain stimulation through microwave research. Non-invasive brain stimulation techniques provide new prospects for comprehending and treating neurological disorders. We investigate the methods shaping the future of deep brain stimulation, emphasizing the role of microwave technology in this transformative journey. Specifically, we explore antenna structures and optimization strategies to enhance the efficiency of high-frequency microwave stimulation. These advancements can potentially revolutionize the field by providing a safer and more precise means of modulating neural activity. Furthermore, we address the challenges that researchers currently face in the realm of microwave brain stimulation. From safety concerns to methodological intricacies, this survey outlines the barriers that must be overcome to fully unlock the potential of this technology. This survey serves as a roadmap for advancing research in microwave brain stimulation, pointing out potential directions and innovations that promise to reshape the field.

A Combined Magnetoelectric Sensor Array and MRI-Based Human Head Model for Biomagnetic FEM Simulation and Sensor Crosstalk Analysis

Magnetoelectric (ME) magnetic field sensors are novel sensing devices of great interest in the field of biomagnetic measurements. We investigate the influence of magnetic crosstalk and the linearity of the response of ME sensors in different array and excitation configurations. To achieve this aim, we introduce a combined multiscale 3D finite-element method (FEM) model consisting of an array of 15 ME sensors and an MRI-based human head model with three approximated compartments of biological tissues for skin, skull, and white matter. A linearized material model at the small-signal working point is assumed. We apply homogeneous magnetic fields and perform inhomogeneous magnetic field excitation for the ME sensors by placing an electric point dipole source inside the head. Our findings indicate significant magnetic crosstalk between adjacent sensors leading down to a 15.6% lower magnetic response at a close distance of 5 mm and an increasing sensor response with diminishing crosstalk effects at increasing distances up to 5 cm. The outermost sensors in the array exhibit significantly less crosstalk than the sensors located in the center of the array, and the vertically adjacent sensors exhibit a stronger crosstalk effect than the horizontally adjacent ones. Furthermore, we calculate the ratio between the electric and magnetic sensor responses as the sensitivity value and find near-constant sensitivities for each sensor, confirming a linear relationship despite magnetic crosstalk and the potential to simulate excitation sources and sensor responses independently.