Maryse A van't Klooster1, Geertjan Huiskamp2, Maeike Zijlmans3, René M Chr Debets4, Emile F I Comans5, Sandrine Bouvard6, Philippe Ryvlin7, Frans S S Leijten2. 1. Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands. Electronic address: m.a.vanhetklooster-2@umcutrecht.nl. 2. Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands. 3. Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands; SEIN - Stichting Epilepsie Instellingen Nederland, Heemstede, The Netherlands. 4. SEIN - Stichting Epilepsie Instellingen Nederland, Heemstede, The Netherlands. 5. Department of Radiology & Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands. 6. CERMEP - Imagerie du Vivant, Bron, France; Translational and Integrative Group in Epilepsy (TIGER), Lyon Neuroscience Research Center, INSERM U1028 - CNRS UMR5292, Bron, France. 7. Institute for Child and Adolescent with Epilepsy (IDEE), Hospices Civils de Lyon, Bron, France; Translational and Integrative Group in Epilepsy (TIGER), Lyon Neuroscience Research Center, INSERM U1028 - CNRS UMR5292, Bron, France.
Abstract
PURPOSE: [(18)F] Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) is a semi-invasive, interictal method of localization of hypometabolic epileptic foci. FDG-PET can be useful in the clinical work-up prior to epilepsy surgery, especially in equivocal cases. We investigated whether we could increase the yield of presurgical FDG-PET in patients with difficult epilepsy requiring chronic subdural electrocorticography (ECoG). METHODS: We retrospectively studied patients with refractory focal epilepsy in whom there was uncertainty about the focus localization and who underwent FDG-PET and ECoG. Two experts (epileptologist and nuclear medicine radiologist) together systematically re-assessed the scans visually (PETRE), blinded to their initial reports. Scans were also re-analyzed by comparing them to a normal control dataset with Statistical Parametric Mapping (SPM), using a liberal (PETSPM1), and strict (PETSPM2) statistical threshold. Regions with hypometabolism and regions containing the seizure onset zone (SOZ) in ECoG were marked as positive anatomical regions (PARs). We compared the concordance of these PARs for the different PET re-assessments. We calculated the sensitivity, specificity and accuracy of the PET results for the SOZ. The added value of the re-assessments was evaluated with emphasis on scans initially reported as negative. RESULTS: 41 Patients (63% extra-temporal) were included. PETRE identified the SOZ best, with a sensitivity of 62% and specificity of 93%. PETSPM1 had a sensitivity of 62% and specificity 69%, for PETSPM2 this was 35% and 85% respectively. The overlap between PETRE vs. PETSPM1 and vs. PETSPM2 was 71% and 37%. Visual re-assessment and PETSPM1 identified the SOZ in four out of five scans that were initially reported as negative. CONCLUSIONS: Pre-surgical re-assessment of PET scans is worthwhile in epilepsy patients who undergo ECoG, especially when results were reported as negative before. Visual re-assessment itself has a higher combined specificity, sensitivity and accuracy than SPM analysis alone. SPM analysis could be used as a guide for visual (re-)assessment, because of its high sensitivity.
PURPOSE: [(18)F] Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) is a semi-invasive, interictal method of localization of hypometabolic epileptic foci. FDG-PET can be useful in the clinical work-up prior to epilepsy surgery, especially in equivocal cases. We investigated whether we could increase the yield of presurgical FDG-PET in patients with difficult epilepsy requiring chronic subdural electrocorticography (ECoG). METHODS: We retrospectively studied patients with refractory focal epilepsy in whom there was uncertainty about the focus localization and who underwent FDG-PET and ECoG. Two experts (epileptologist and nuclear medicine radiologist) together systematically re-assessed the scans visually (PETRE), blinded to their initial reports. Scans were also re-analyzed by comparing them to a normal control dataset with Statistical Parametric Mapping (SPM), using a liberal (PETSPM1), and strict (PETSPM2) statistical threshold. Regions with hypometabolism and regions containing the seizure onset zone (SOZ) in ECoG were marked as positive anatomical regions (PARs). We compared the concordance of these PARs for the different PET re-assessments. We calculated the sensitivity, specificity and accuracy of the PET results for the SOZ. The added value of the re-assessments was evaluated with emphasis on scans initially reported as negative. RESULTS: 41 Patients (63% extra-temporal) were included. PETRE identified the SOZ best, with a sensitivity of 62% and specificity of 93%. PETSPM1 had a sensitivity of 62% and specificity 69%, for PETSPM2 this was 35% and 85% respectively. The overlap between PETRE vs. PETSPM1 and vs. PETSPM2 was 71% and 37%. Visual re-assessment and PETSPM1 identified the SOZ in four out of five scans that were initially reported as negative. CONCLUSIONS: Pre-surgical re-assessment of PET scans is worthwhile in epilepsypatients who undergo ECoG, especially when results were reported as negative before. Visual re-assessment itself has a higher combined specificity, sensitivity and accuracy than SPM analysis alone. SPM analysis could be used as a guide for visual (re-)assessment, because of its high sensitivity.
Authors: Anna Mrelashvili; Robert J Witte; Elaine C Wirrell; Katherine C Nickels; Lily C Wong-Kisiel Journal: Pediatr Neurol Date: 2015-09-12 Impact factor: 3.372