TMS targeting using MRI-free head modeling

This is the authors' abstract. We don't add key points for this paper.

Methods to determine coil position are paramount in TMS. Existing approaches are limited to scalp heuristics or depend on some combination of neuronavigation hardware, average brain templates, as well as subject MRI and/or evoked responses. We developed head-model guided TMS targeting without subject MRI, specialized hardware, or evoked responses. The MRI-free approach involves three scalp measurements, akin to Beam-F3, which are then used to generate an individualized head model by applying an affine transformation to the MNI standard head model. Target localization is then performed on this individualized head model for any TMS scalp target. The coil position is then provided to the operator in simple geodesic measurements. This process was simulated on MRI data of fourteen subjects showing a mean error of 4.92 mm from an MRI-based target.