John J. Lee, MD, PhDᵃ, Patrick Luckett, PhDᵇ, Mohammad M. Fakhri, MDᵃ, Eric C. Leuthardt, MDᶜ, Joshua S. Shimony, MD, PhDᵃ,*

ᵃMallinckrodt Institute of Radiology, Washington University, 4525 Scott Avenue, St Louis, MO 63110, USA

ᵇDepartment of Neurology, Washington University School of Medicine, 4525 Scott Avenue, St Louis, MO 63110, USA

ᶜDepartment of Neurological Surgery, Washington University School of Medicine, 4525 Scott Avenue, St Louis, MO 63110, USA

INTRODUCTION

Localization of language regions using task-based functional MR imaging (T-fMR imaging) is currently considered standard of care before surgical resection of brain lesions that may impinge on these critical areas of the brain (“eloquent cortex”). This information is considered critical for presurgical planning, assessing the risk for morbidity, and consultation with patients and their families. This method is most often used for brain tumor resection, but has become common in numerous other neurosurgical procedures such as epilepsy surgery, brain biopsies, and laser ablation procedures.

Mapping language function accurately is complicated by several factors such as the numerous components of the language system (receptive vs expressive language, memory, reading, listening, and speaking that involve components of vision, hearing, and the motor systems), and the variability of its location across patients even after hemispheric dominance is established. Further complicating the surgical plan is the need to integrate this information between aggressive resection (that can extend life and delay recurrence) and functional preservation (decreasing morbidity), which can differ depending on the exact location of the tumor with respect to different parts of the language system. Some areas of the language system will not recover from resection (e.g., Broca’s area), but others may be fully restored after recovery time and therapy (e.g., supplementary motor area).