When imaging meets neurophysiology: the value of navigated transcranial magnetic stimulation for preoperative neurophysiological mapping prior to brain tumor surgery

Neurosurg Focus. 2019 Dec 1;47(6):E10. doi: 10.3171/2019.9.FOCUS19640.

Abstract

Maximal safe resection is the modern goal for surgery of intrinsic brain tumors located in or close to brain eloquent areas. Nowadays different neuroimaging techniques provide important anatomical and functional information regarding the brain functional organization that can be used to plan a customized surgical strategy to preserve functional networks, and to increase the extent of tumor resection. Among these techniques, navigated transcranial magnetic stimulation (nTMS) has recently gained great favor among the neurosurgical community for preoperative mapping and planning prior to brain tumor surgery. It represents an advanced neuroimaging technique based on the neurophysiological mapping of the functional cortical brain organization. Moreover, it can be combined with other neuroimaging techniques such as diffusion tensor imaging tractography, thus providing a reliable reconstruction of brain eloquent networks. Consequently, nTMS mapping may provide reliable noninvasive brain functional mapping, anticipating information that otherwise may be available to neurosurgeons only in the operating theater by using direct electrical stimulation. The authors describe the reliability and usefulness of the preoperative nTMS-based approach in neurosurgical practice, and briefly discuss their experience using nTMS as well as currently available evidence in the literature supporting its clinical use. In particular, special attention is reserved for the discussion of the role of nTMS as a novel tool for the preoperative neurophysiological mapping of motor and language networks prior to surgery of intrinsic brain tumors located in or close to eloquent networks, as well as for future and promising applications of nTMS in neurosurgical practice.

Keywords: AF = arcuate fascicle; CST = corticospinal tract; DCS = direct cortical stimulation; DES = direct electrical stimulation; DSS = direct subcortical stimulation; DTI = diffusion tensor imaging; DTI tractography; FA = fractional anisotropy; IFOF = inferior frontooccipital fascicle; ILF = inferior longitudinal fascicle; M1 = primary motor cortex; MEP = motor evoked potential; RMT = resting motor threshold; ROI = region of interest; SLF = superior longitudinal fascicle; UF = uncinate fascicle; brain tumors; diffusion tensor imaging; eloquent areas; fMRI = functional MRI; nTMS = navigated transcranial magnetic stimulation; navigated transcranial magnetic stimulation; neurophysiological mapping; presurgical planning; rTMS = repetitive transcranial magnetic stimulation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Video-Audio Media

MeSH terms

  • Adult
  • Aged
  • Brain Mapping / methods*
  • Brain Neoplasms / diagnostic imaging*
  • Brain Neoplasms / secondary
  • Brain Neoplasms / surgery
  • Diffusion Tensor Imaging / methods
  • Evoked Potentials, Motor
  • Female
  • Glioma / diagnostic imaging*
  • Glioma / surgery
  • Humans
  • Language
  • Male
  • Middle Aged
  • Motor Cortex / diagnostic imaging
  • Neuronavigation / methods*
  • Preoperative Care / methods*
  • Speech / physiology
  • Transcranial Magnetic Stimulation / instrumentation
  • Transcranial Magnetic Stimulation / methods*