Comparison of Head Pose Tracking Methods for Mixed-Reality Neuronavigation for Transcranial Magnetic Stimulation

Repetitive Transcranial Magnetic Stimulation (rTMS) is an important treatment option for medication resistant depression. It uses an electromagnetic coil that needs to be positioned accurately at a specific location and angle next to the head such that specific brain areas are stimulated. Existing image-guided neuronavigation systems allow accurate targeting but add cost, training and setup times, preventing their wide-spread use in the clinic. Mixed-reality neuronavigation can help mitigate these issues and thereby enable more widespread use of image-based neuronavigation by providing a much more intuitive and streamlined visualization of the target. One of the main functionalities of such a system is tracking of the patient’s head.

In this paper, we integrate three head tracking methods into the mixed reality neuronavigation framework and compare their accuracy. Specifically, we experimented with (a) marker-based tracking with a mixed reality headset (optical see-through head-mounted display (OST-HMD)) camera, (b) marker-based tracking with a world-anchored camera and (c) markerless RGB-depth (RGB-D) tracking with a world-anchored camera. It was observed that for the initial head pose, all three methods achieved the required accuracy of < 5 mm for TMS treatment. For smaller head rotations of 10◦, only the marker-based (a) and markerless method (c) delivered sufficient accuracy for TMS treatment. For larger head rotations of 30◦ , only the marker-based method (a) achieved sufficient accuracy. While the markerless method (c) did not provide sufficient accuracy for TMS at the larger head rotations, it offers significant advantages such as occlusion-handling and stability and could potentially meet the accuracy requirements with further methodological refinements.

Sathyanarayana S, Leuze C, Hargreaves B, Daniel B, Wetzstein G, Etkin A, Bhati MT, McNab JA. Comparison of head pose tracking methods for mixed-reality neuronavigation for transcranial magnetic stimulation. Proc. SPIE 11315, Medical Imaging 2020: Image-Guided Procedures, Robotic Interventions, and Modeling, 113150L (16 March 2020); doi: 10.1117/12.2547917.

Online Conference Paper