RSNA 2007 

Abstract Archives of the RSNA, 2007


SSK13-01

Comprehensive Phase 1 Epileptogenic Focus Localization Compared with Postsurgical Pathology and Seizure Reduction Outcome in Pediatric Epilepsies

Scientific Papers

Presented on November 28, 2007
Presented as part of SSK13: Pediatric (Neuroradiology)

Participants

Ashok Muthukrishnan MD, Presenter: Nothing to Disclose
Samuel P. Pak MD, Abstract Co-Author: Nothing to Disclose
Lorcan Aloysius O'Tuama MD, Abstract Co-Author: Nothing to Disclose
James Michael Mountz MD, PhD, Abstract Co-Author: Nothing to Disclose

PURPOSE

Ictal,interictal cerebral perfusion SPECT and F-18 FDG PET have been routinely used in pre-surgical identification of epileptogenic foci as part of phase I evaluation. In consideration of temporal lobe(TE) and extratemporal(ET) epilepsies, issues such as multiple epileptogenic foci, distinctive behavior of ET and effects of concurrent anatomic abnormalities often complicate the localization of seizure foci. We analyzed all these modalities with respect to other techniques and post-surgical outcome in our pediatric population.

METHOD AND MATERIALS

23 epilepsy patients(age range 3-17), 11 with temporal lobe (TL) epilepsy and 13 with extra-temporal(ET) lobe underwent video EEG monitoring, interictal and ictal cerebral SPECT, interictal F-18 FDG PET, MRI, invasive EEG and surgery. The ictal and interictal SPECT were digitally subtracted using computerized subtraction analysis using Subtraction Ictal SPECT CO-registered to MRI (SISCOM). The PET scan was evaluated for focal areas of hypometabolism visually and using Statistical Parametric Analysis comparing with normal control groups. The findings were correlated with postsurgical seizure-reduction outcome (Engel’s criteria) and histopathological diagnosis.

RESULTS

In 11 patients with temporal lobe epilepsy, PET correctly localized 9 epileptogenic foci and the remaining 2 were false negative. Ictal SPECT identified 10/11 and was false positive in 1. In ET,FDG PET showed focal hypometabolism in 3/13 patients whereas SPECT correctly localized the seizure focus in 9 patients. In 4 patients with ET, there were large areas of encephalomalacia(2)or tuberous sclerosis(2), which showed large areas of FDG reduction on PET. But in 3 of these, the seizure focus was correctly identified on SPECT.

CONCLUSION

In TE, SPM FDG-PET was localizing in 9/11 cases vs. 10/11 SISCOM SPECT suggesting that if localization was accomplished by FDG, ictal SPECT may not be necessary. In ET, only 3/13 were localized by PET, whereas 9/11 were localized by SISCOM SPECT indicating the latter’s valuable role in localization of epileptogenic focus.

CLINICAL RELEVANCE/APPLICATION

The authors present a simple and systematic diagnostic approach for pre-surgical imaging evaluation in seizures.

Cite This Abstract

Muthukrishnan, A, Pak, S, O'Tuama, L, Mountz, J, Comprehensive Phase 1 Epileptogenic Focus Localization Compared with Postsurgical Pathology and Seizure Reduction Outcome in Pediatric Epilepsies.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5016714.html