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Comparative Study
. 2012 Mar;71(3):334-41.
doi: 10.1002/ana.22619.

Optic radiation tractography and vision in anterior temporal lobe resection

Gavin P Winston  1 , Pankaj Daga, Jason Stretton, Marc Modat, Mark R Symms, Andrew W McEvoy, Sebastien Ourselin, John S Duncan
Affiliations
Free PMC article
Comparative Study

Optic radiation tractography and vision in anterior temporal lobe resection

Gavin P Winston et al. Ann Neurol. 2012 Mar.
Free PMC article

Abstract

Objective: Anterior temporal lobe resection (ATLR) is an effective treatment for refractory temporal lobe epilepsy but may result in a contralateral superior visual field deficit (VFD) that precludes driving in the seizure-free patient. Diffusion tensor imaging (DTI) tractography can delineate the optic radiation preoperatively and stratify risk. It would be advantageous to incorporate display of tracts into interventional magnetic resonance imaging (MRI) to guide surgery.

Methods: We studied 20 patients undergoing ATLR. Structural MRI scans, DTI, and visual fields were acquired before and 3 to 12 months following surgery. Tractography of the optic radiation was performed on preoperative images and propagated onto postoperative images. The anteroposterior extent of the damage to Meyer's loop was determined, and visual loss was quantified using Goldmann perimetry.

Results: Twelve patients (60%) suffered a VFD (10-92% of upper quadrant; median, 39%). Image registration took <3 minutes and predicted that Meyer's loop was 4.4 to 18.7mm anterior to the resection margin in these patients, but 0.0 to 17.6mm behind the resection margin in the 8 patients without VFD. The extent of damage to Meyer's loop significantly correlated with the degree of VFD and explained 65% of the variance in this measure.

Interpretation: The optic radiation can be accurately delineated by tractography and propagated onto postoperative images. The technique is fast enough to propagate accurate preoperative tractography onto intraoperative scans acquired during neurosurgery, with the potential to reduce the risk of VFD.

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Figures

FIGURE 1
FIGURE 1
Preoperative structural T1-weighted image and optic radiation (A) and postoperative structural T1-weighted image with propagated preoperative tractography (B) show that part of the optic radiation was resected (blue) in patient 7, who developed a severe visual field deficit (VFD). Corresponding preoperative (C) and postoperative images (D) are shown in patient 12, who did not develop a VFD.
FIGURE 2
FIGURE 2
Measurement of the anteroposterior extent of resection of Meyer's loop.
FIGURE 3
FIGURE 3
Correlation between measured visual field deficit and the predicted damage to Meyer's loop by image registration. A-P = anterior-posterior.
See this image and copyright information in PMC

References

    1. Semah F, Ryvlin P. Can we predict refractory epilepsy at the time of diagnosis? Epileptic Disord. 2005;7(suppl 1):S10–S13. - PubMed
    1. Wiebe S, Blume WT, Girvin JP, et al. A randomized, controlled trial of surgery for temporal-lobe epilepsy. N Engl J Med. 2001;345:311–318. - PubMed
    1. Nilsson D, Malmgren K, Rydenhag B, et al. Visual field defects after temporal lobectomy—comparing methods and analysing resection size. Acta Neurol Scand. 2004;110:301–307. - PubMed
    1. Barton JJ, Hefter R, Chang B, et al. The field defects of anterior temporal lobectomy: a quantitative reassessment of Meyer's loop. Brain. 2005;128:2123–2133. - PubMed
    1. Pathak-Ray V, Ray A, Walters R, et al. Detection of visual field defects in patients after anterior temporal lobectomy for mesial temporal sclerosis—establishing eligibility to drive. Eye (Lond) 2002;16:744–748. - PubMed

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