Optic radiation tractography appears beneficial in temporal lobe epilepsy

This study found that optic radiation tractography helped reduced visual field deficits in patients undergoing anterior temporal lobe resection for refractory temporal lobe epilepsy.

However, the use of this imaging did not affect seizure outcome or hippocampal resection. Additionally, correction for brain shift using the technology did not further improve outcomes.

The authors compared outcomes of 21 patients who underwent anterior temporal lobe resection using optic radiation tractography with 44 who underwent the same procedure by the same surgeon but without using intraoperative MRI guidance.

Visual field deficits in the contralateral superior quadrant were significantly less in the group that used optic radiation tractography.

No patient in the intraoperative MRI cohort developed a visual field deficit that precluded driving whereas 13% of the non-intraoperative MRI cohort failed to meet driving standards for the United Kingdom, where the study was conducted.

Seizure outcome and degree of hippocampal resection were similar between the groups. Preoperative tractography corrected for brain shift in 12 of the 21 patients but not produce any further improvements.

Since interventional MRI is expensive, prolongs surgery and is not widely available, the authors say their next step is to assess the benefit of incorporation of probabilistic tractography of the optic radiation into the operating microscope display of a commonly used neuronavigation system, such as StealthStation (Medtronic), which would make this advance widely applicable. They are also exploring more economical ways of correcting for brain shift, such as intraoperative ultrasound.