Functional magnetic resonance imaging for language mapping in temporal lobe epilepsy

Abstract

Functional magnetic resonance imaging (fMRI) is a noninvasive technique that is increasingly used to understand the cerebral cortical networks and organizations. In this paper, we describe the role of fMRI for mapping language networks in the presurgical workup of patients with medically intractable temporal lobe epilepsy (TLE). Studies comparing fMRI with the intracarotid sodium amobarbital (Wada) test and fMRI with intraoperative cortical stimulation mapping for language lateralization and/or localization in medically intractable TLE are discussed.

Figure 1

Schematic diagram of a verb generation task used at our centre.

Figure 2

fMRI activation map overlaid on anatomical images.

Figure 3

Axial T₂ (a) and axial diffusion-weighted (b) images of a TLE patient who experienced a stroke in the right middle cerebral artery territory secondary to a traumatic dissection of the right internal carotid artery during the sodium amobarbital testing.

Figure 4

Electrocortical stimulation (ESM) sites from 13 patients with TLE of the left temporal lobe origin that are spatially normalized to MNI space and fused with MNI single subject brain.

Figure 5

Overlay of intraoperative cortical images with fMRI for comparison. (a) Shows the intraoperative cortical photograph acquired just after ESM on the left temporal lobe. (b) Shows the overlay of this photograph onto volume-rendered anatomical MRI and fMRI. Arrows indicate where the label “F” is in the two images.