Abstracts

Rationale: Ictal single photon emission computed tomography (SPECT) is a commonly utilized evaluation in patients with focal intractable epilepsy with Tuberous Sclerosis Complex (TSC) [1]. Typical factors in successful SPECT localization include focal EEG rhythms, temporal location, and rapid tracer injection. [2][3] When the electroencephalogram (EEG) pattern is poorly localizing, determination of seizure onset is difficult. We describe a case of SPECT use with minimal EEG features during the ictal state which well isolated a target tuber.

Methods: A female child with intractable epilepsy, daily seizures, and a pathogenic TSC1 mutation underwent pre-surgical evaluation. Seizures were described as “chills” and appeared as a cluster of rapid, symmetric jerks of the upper extremities, with or without progression to staring, decreased responsiveness, and vocalization. EEGs demonstrated multifocal and generalized epileptiform discharges, focal slowing, most consistently involving left temporal regions. Magnetic resonance imaging (MRI) showed multiple cortical and subcortical tubers. Ictal EEG pattern revealed pseudonormalization of the EEG background and periodic sharps in the T5 T3 region time-locked to upper extremity myoclonus. Localization to a single target tuber was not possible based on EEG or MRI, thus ictal SPECT injection of a cluster of myoclonic jerks was performed. SPECT injection occurred 46 seconds after the initial change in EEG background and during recurrent myoclous. MRI and EEG data were imported into Compumedics CURRY8 for Electroencephalographic Source Imaging (ESI) and SPECT and Computed Tomography (CT) data were coregistered.

Results: Ictal SPECT hyperperfusion colocalized to the region identified by ESI of the periodic discharges, a left temporal tuber. Following review of the data, the ictal SPECT provided strongest imaging evidence of seizure localization while validating the remainder of the multimodal evaluation. The patient is planned for a one stage resection of the tuber and adjacent tissue and results will be available for inclusion into the abstract.

Conclusions: Ictal SPECT injection during a cluster of myoclonic seizures of presumed focal origin may provide strong localizing data, even in the absence of clear ictal evolution on scalp EEG.

[1] Jayakar P, Gaillard WD, Tripathi M, Libenson MH, Mathern GW, Cross JH. Diagnostic test utilization in evaluation for resective epilepsy surgery in children. Epilepsia 2014;55:507–18.

[2] Stamoulis C, Verma N, Kaulas H, Halford JJ, Duffy FH, Pearl PL, et al. The promise of subtraction ictal SPECT co-registered to MRI for improved seizure localization in pediatric epilepsies: Affecting factors and relationship to the surgical outcome. Epilepsy Res 2017;129:59–66.

[3] Kudr M, Krsek P, Maton B, Malone S, Jahodova A, Jezdik P, et al. Predictive factors of ictal SPECT findings in paediatric patients with focal cortical dysplasia. Epileptic Disord 2013;15:383–91.

Funding: Please list any funding that was received in support of this abstract.: No sources of funding were utilized for this submission.