Perfusion patterns during temporal lobe seizures: relationship to surgical outcome

Area of Science:

• Neurology
• Nuclear Medicine
• Epilepsy Surgery

Background:

• Temporal lobe epilepsy (TLE) is a common cause of drug-resistant epilepsy.
• Predicting surgical outcomes after temporal lobectomy is crucial for patient management.
• Ictal hyperperfusion patterns on SPECT may offer prognostic information.

Purpose of the Study:

• To investigate if ictal hyperfusion patterns on technetium Tc 99m HMPAO SPECT predict outcomes after temporal lobectomy.
• To determine if more extensive hyperperfusion patterns are associated with poorer surgical results.

Main Methods:

• Sixty-three patients with TLE underwent ictal SPECT using [99mTc]HMPAO before temporal lobectomy.
• Ictal hyperperfusion patterns were classified as typical, typical with posterior extension, bilateral, or atypical.
• Outcomes were assessed at a minimum of 2 years post-surgery (seizure-free vs. not seizure-free).
• Actuarial analysis was used to correlate SPECT patterns with outcomes.

Main Results:

• Typical, posterior extension, and bilateral patterns showed similar seizure-free rates (60-69%).
• Atypical patterns were associated with a significantly lower seizure-free rate (33%) and lack of surgical pathology.
• Actuarial analysis confirmed a significant difference in outcome between typical and atypical SPECT patterns (P=0.04).

Conclusions:

• Extended ictal hyperperfusion patterns in TLE do not predict poor surgical outcomes.
• Atypical hyperperfusion patterns are linked to worse outcomes, suggesting diffuse or extra-temporal epileptogenicity.
• Ictal SPECT patterns can aid in predicting the success of temporal lobectomy for epilepsy.