Subtraction Ictal SPECT coregistered to MRI (SISCOM) as a guide in localizing childhood epilepsy

Abstract

Objective To assess feasibility and efficacy of subtraction ictal SPECT coregistered to MRI (SISCOM) for epilepsy localization in children who are candidates for resective surgery. Methods We retrospectively reviewed all patients ≤16 years with drug‐resistant epilepsy screened for epilepsy surgery in the University Hospital of Leuven from January 2009 to January 2018. Fifty‐eight hospitalizations for ictal SPECT and 51 SISCOM analyses in 44 patients were included. Mean age was 9.1 years. Hospitalizations for SISCOM were analyzed in terms of multiple variables affecting feasibility and efficacy. The localization of SISCOM was compared with the localization of the presumed epileptogenic zone (PEZ) as determined by video‐EEG. Results SISCOM was feasible in terms of chronic medication management, rescue antiepileptic therapy during hospitalization, and operative timings. Radiotracer injection occurred within 30 seconds from seizure onset in 91.4% of the patients. ictal SPECT imaging was performed within two hours from injection in 100% of the patients (mean: 40 minutes). SISCOM was able to localize the PEZ in 51.0% (26/51) and to additionally lateralize the PEZ in 17.6% (9/51), achieving better localizations than ictal SPECT, FDG‐PET, and MRI (P < .01). SISCOM was useful to localize the PEZ in 25% of patients with poorly localizing video‐EEG and in 27.8% of MRI‐negative cases. The occurrence of habitual seizures during injection for ictal SPECT and the temporal localization of the PEZ both correlated with a better SISCOM localization (P < .05). 36.4% (16/44) patients were finally selected for resective surgery, with a 87.5% seizure‐free rate at 12 months. A localizing SISCOM was associated with seizure freedom in 66.7% and with a Engel I‐II in 75.0% of our patients. Significance SISCOM is a reliable tool to localize the epileptogenic zone in clinical practice and is both feasible and useful in children, adding precious presurgical information especially in patients with noninformative MRI or a poorly localizing video‐EEG.

Comparative contribution of magnetoencephalography (MEG) and single-photon emission computed tomography (SPECT) in pre-operative localization for epilepsy surgery: A prospective blinded study

“…Our results are in agreement with previous findings, although studies have previously reported better results with respect to odds ratio of good outcome [17]. On the other hand, very few studies have evaluated the concordance of SPECT localization with surgical outcomes [28][29][30]. A previously conducted meta-analysis predicted better outcome for SPECT findings than was reported in our study [31].…”

The Legacy of the TTASAAN Report—Premature Conclusions and Forgotten Promises: A Review of Policy and Practice Part I

“…Automated injectors can reduce lag time from 60 s with hand administration to 18.5 s using an automated method ( 175 ). Since seizure activity is initially limited to the focus/foci, but then spreads to adjacent or even contralateral brain areas, capturing the perfusion pattern early increases the accuracy of the localization by perfusion SPECT ( 176 , 177 ). For example, using automated injectors increased localization of seizure foci from 62.9 to 81.8% ( 175 ).…”

Stereoelectroencephalography versus Subdural Electrode Implantation to Determine Whether Patients with Drug-resistant Epilepsy Are Candidates for Epilepsy Surgery

“…Ictal single-photon emission computed tomography (SPECT) may identify areas of hyperperfusion while subtraction of ictal-interictal SPECT co-registered to MRI (SISCOM) has been shown to provide high sensitivity and specificity for identification of an EZ, particularly in temporal lobe locations in both adult and pediatric patients. 26 , 27) This technique is limited by the resource-intensiveness implicit to obtaining ictal studies. MEG or functional MRI (fMRI) may have utility in surgical planning by way of providing identification of eloquent cortex.…”