Fig. 1.

Illustration of our highly standardized protocol. A patient with a (post)central glioma (WHO IV°) is presented (A, B). Navigated TMS stimuli locations along the precentral gyrus were elicited with 105% RMT for the upper and with 130%–150% RMT for the lower extremity (C) and then exported into our fiber tracking software iPlan 3.0 as region of interests with a radius of 3 mm (visualized as yellow balls in H and I). The second ROI was seeded in one layer of the caudal pons (E) where the blue color in the color-coded FA-map represents the anterior-posterior pontine course of the pyramidal tract (D and F). Finally, FT was performed with 75% FAT where the tumor is colored in red, the CST of the upper extremity in blue and the CST of the lower extremity in green (G, H, I). In this case, we would recommend the use of IOM – especially during the ventral tumor debulking because the tumor seems to begin infiltrating the CST (G).