Title:Common Ictal and Interictal Perfusion Patterns: A Window into the Epileptogenic
Network and SUDEP Mechanism in Drug-Resistant Focal Epilepsy
Volume: 28
Issue: 14
Author(s): Lilia M. Morales Chacón*, Lidice Galan García, Karla Batista García-Ramón, Margarita Minou Báez Martin, Jorge Bosch-Bayard, Maydelis Alfonso Alfonso, Sheyla Berrillo Batista, Tania de la Paz Bermudez, Judith González González, Abel Sánchez Coroneaux, Ángel Águila Ruiz, Marlene Perera Roque and Leysi Murada Matamoro
Affiliation:
- Clinical Neurophysiology Department, International Center for Neurological Restoration. Avenida 25 e/ 158 y 160 No 15805,
Habana, Cuba
Keywords:
Single photon emission computed tomography, ictal SPECT, interictal SPECT, drug-resistant focal epilepsy, SUDEP, hypoperfused.
Abstract:
Background: Focal epilepsies have been described as a network disease. Noninvasive investigative
techniques have been used to characterize epileptogenic networks.
Objective: This study aimed to describe ictal and interictal cortical and subcortical perfusion patterns using single-
photon emission computed tomography (SPECT) in patients with drug-resistant epilepsy (DRE).
Methods: Thirty-five interictal-ictal SPECT scans were obtained from 15 patients with DRE. A methodology
was developed to get a relative perfusion index (PI) of 74 cortical and sub-cortical brain structures. K-means
algorithm, together with modified v-fold cross-validation, was used to identify the two regions of interest
(ROIs) that represent hypoperfused and hyperperfused areas.
Results: In common with the individual analysis, the statistical analysis evidenced that the hyperperfusion ROIs
resulting from group analysis during interictal and ictal involved mainly the cingulate gyrus, cuneus, lingual
gyrus, and gyrus rectus as well as the putamen. ROIs hypoperfused included the red nucleus, the substantia
nigra, and the medulla. The medians of the group analysis of the hypoperfusion and hyperperfusion ROIs were
0.601-0.565 and 1.133-1.119 for the ictal and interictal states, correspondingly. A group of mostly cortical
structures involved in the hyperperfused ROIs in both interictal and ictal states showed no change or negative
change in the transition from interictal to ictal state (mean change of -0.002). On the other hand, the brain stem,
basal ganglia, red nucleus, and thalamus revealed a mean global change of 0.19, indicating a mild increase in
the PI. However, some of these structures (red nucleus, substantia nigra, and medulla oblongata) remained hypoperfused
during the interictal to ictal transition.
Conclusion: The methodology employed made it possible to identify common cortical and subcortical perfusion
patterns not directly linked to epileptogenicity, for a better epileptogenic network and sudden unexpected
death (SUDEP) mechanism in DRE.
