Volume 44, Issue 3 pp. 399-407

Presurgical Evaluation of Epilepsy by Brain Diffusion: MR-detected Effects of Flumazenil on the Epileptogenic Focus

Stefan Konermann

Stefan Konermann

Departments of Neurology,

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Sonja Marks

Sonja Marks

Departments of Neurology,

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Tanja Ludwig

Tanja Ludwig

Departments of Neurology,

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Johannes Weber

Johannes Weber

Neuroradiology, and

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Armin De Greiff

Armin De Greiff

Departments of Neurology,

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Arnd Dörfler

Arnd Dörfler

Neuroradiology, and

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Georg Leonhardt

Georg Leonhardt

Departments of Neurology,

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Helmut Wiedemayer

Helmut Wiedemayer

Neurosurgery, University of Essen, Essen, Germany

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Hans-Christoph Diener

Hans-Christoph Diener

Departments of Neurology,

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Andreas Hufnagel

Andreas Hufnagel

Departments of Neurology,

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First published: 07 March 2003
Citations: 29
Address correspondence and reprint requests to Dr. S. Konermann at Department of Neurology, University Essen, Hufelandstr. 55, D-45122 Essen, Germany. E-mail: [email protected]

Abstract

Summary: Purpose: After focal status epilepticus, focal alterations of the apparent diffusion coefficient (ADC) have been demonstrated in the epileptogenic zone by using diffusion-weighted magnetic resonance (MR)imaging (DWI). Effects of flumazenil on an epileptogenic focus have been demonstrated by EEG recordings, but not by functional MRI. We hypothesized that dynamic spatiotemporal alterations of brain diffusion of the epileptogenic focus after application of flumazenil will be detectable by DWI and correlate with the epileptogenic zone.

Methods: Twelve adult patients considered for epilepsy surgery with medically intractable temporal lobe epilepsy (TLE; n = 7), extratemporal lobe epilepsy (ETE; n = 2), and TLE+ETE (n = 3) were prospectively examined with DWI interictally (serving as baseline) and 10 min after application of 1 mg flumazenil i.v.

Results: The baseline interictal ADC was significantly elevated in the hippocampus on the ictogenic side in the patients with TLE (p = 0.002) as compared with healthy volunteers. The following changes of the mean ADC were seen in different regions of interest (ROIs) after injection of flumazenil: decreases in the hippocampus on the seizure-onset side by 14.8% (p = 0.005); decreases in the parahippocampal gyrus on both sides by 6.8% (epileptogenic side; p = 0.044) or 7.9% (nonepileptogenic side; NS), respectively; decreases in the cortex on the nonictogenic side by 7.9% (p = 0.047); and no significant changes of the ADC in the other ROIs.

Conclusions: ADC decreases measured after application of flumazenil were seen in the seizure-onset zone as revealed by EEG and structural MRI and are an indicator of focus localization in patients with TLE.

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