Invasive versus non‐invasive mapping of the motor cortex

• Published in: Human brain mapping 2020-10, Vol.41 (14), p.3970-3983
• Main Authors: Weiss Lucas, Carolin, Nettekoven, Charlotte, Neuschmelting, Volker, Oros‐Peusquens, Ana‐Maria, Stoffels, Gabriele, Viswanathan, Shivakumar, Rehme, Anne K., Faymonville, Andrea Maria, Shah, N. Jon, Langen, Karl Josef, Goldbrunner, Roland, Grefkes, Christian
• Format: Article
• Language: English
• Subjects: Brain cancer; Brain mapping; Brain tumors; brain tumours; Complications; Cortex (motor); electric stimulation; Functional magnetic resonance imaging; Glioma; Magnetic fields; Magnetic resonance imaging; Mapping; Neuroimaging; precentral motor area; Representations; Risk assessment; surgical procedures, neurologic; Transcranial magnetic stimulation; Tumors
• ISSN: 1065-9471; 1097-0193
• DOI: 10.1002/hbm.25101

Precise and comprehensive mapping of somatotopic representations in the motor cortex is clinically essential to achieve maximum resection of brain tumours whilst preserving motor function, especially since the current gold standard, that is, intraoperative direct cortical stimulation (DCS), holds limitations linked to the intraoperative setting such as time constraints or anatomical restrictions. Non‐invasive techniques are increasingly relevant with regard to pre‐operative risk‐assessment. Here, we assessed the congruency of neuronavigated transcranial magnetic stimulation (nTMS) and functional magnetic resonance imaging (fMRI) with DCS. The motor representations of the hand, the foot and the tongue regions of 36 patients with intracranial tumours were mapped pre‐operatively using nTMS and fMRI and by intraoperative DCS. Euclidean distances (ED) between hotspots/centres of gravity and (relative) overlaps of the maps were compared. We found significantly smaller EDs (11.4 ± 8.3 vs. 16.8 ± 7.0 mm) and better spatial overlaps (64 ± 38% vs. 37 ± 37%) between DCS and nTMS compared with DCS and fMRI. In contrast to DCS, fMRI and nTMS mappings were feasible for all regions and patients without complications. In summary, nTMS seems to be the more promising non‐invasive motor cortex mapping technique to approximate the gold standard DCS results. The motor representations of the hand, the foot and the tongue regions were mapped pre‐operatively using neuronavigated transcranial magnetic stimulation (nTMS) and functional magnetic resonance imaging (fMRI) in thirty six patients with intracranial tumours and were compared with intraoperative direct cortex stimulation (DCS). We found significantly smaller Euclidean distances and better spatial overlaps between DCS and nTMS compared with DCS and fMRI. In summary, nTMS seems to be the more promising non‐invasive motor cortex mapping technique to approximate the gold standard DCS results.