Temporal pole MRI abnormalities in temporal lobe epilepsy

Epileptic Disord. 2002 Sep:4 Suppl 1:S33-9.

Abstract

Magnetic resonance imaging (MRI) demonstrates an abnormal aspect of the temporo-polar region in 1/3 to 2/3 of patients suffering from cryptogenic temporal lobe epilepsy. This abnormal aspect is described as a white matter increased T2 signal, resulting in a loss of gray-white matter demarcation, often associated with atrophy, as recently confirmed by quantitative volumetric measurements. These temporo-polar MRI findings appear to correctly lateralize the epileptogenic temporal lobe with a very high specificity, and have never been reported in extra-temporal lobe epilepsy nor in control subjects. They are usually associated with MRI signs of hippocampal sclerosis, but the two conditions seem to be partly distinct from a pathophysiological point of view. Pathological correlates of temporo-polar white matter increased T2 signal are controversial, but the role of an abnormal myelin seems more likely than that of ectopic neurons. A myelin dysfunction would also be consistent with the correlation observed between lateral temporal hypometabolism and temporo-polar MRI abnormalities. Whether or not these MRI findings are associated with a better seizure outcome following temporal lobectomy remains a debated issue.

MeSH terms

  • Atrophy / pathology
  • Atrophy / surgery
  • Epilepsy, Temporal Lobe / diagnosis*
  • Epilepsy, Temporal Lobe / surgery
  • Flumazenil / pharmacokinetics
  • GABA Modulators / pharmacokinetics
  • Humans
  • Magnetic Resonance Imaging*
  • Temporal Lobe / abnormalities*
  • Temporal Lobe / metabolism
  • Temporal Lobe / surgery
  • Tomography, Emission-Computed

Substances

  • GABA Modulators
  • Flumazenil