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Utility of gray-matter segmentation of ictal-Interictal perfusion SPECT and interictal 18F-FDG-PET in medically refractory epilepsy.
Epilepsy Res 2017; 130:93-100ER

Abstract

PURPOSE

We present a method of gray-matter segmentation of functional neuroimaging for localization of seizure onset zone (SOZ) in epilepsy surgery. 18F-FDG-PET hypometabolism and ictal SPECT hyperperfusion may correspond to SOZ. We hypothesize that limiting functional images to gray matter improves identification of small, subtle, or obscure cortical volumes of 18F-FDG-PET hypometabolism and eliminates hyperperfused seizure propagation pathways within white matter in ictal perfusion SPECT.

METHODS

Twenty-five adult and pediatric patients age 2-48 years with epilepsy surgery evaluations consisting of MRI, 18F-FDG-PET, ictal and interictal perfusion SPECT, and intracranial EEG (iEEG) monitoring were selected. MRI gray matter segmentation was used to identify cortical regions in coregistered 18F-FDG-PET and Ictal-Interictal SPECT Analysis by SPM (ISAS) as volumes of interest (VOI). VOIs in 18F-FDG-PET and SPECT perfusion clusters were compared to iEEG localization. The level of VOI concordance between two modalities was recorded as the same subgyrus (highest concordance), gyrus, sublobe, lobe, hemisphere, or no concordance.

RESULTS

With segmentation, 84% (21/25) of cases had at least one area identified on 18F-FDG-PET scan concordant with iEEG SOZ at sublobar or higher levels, and 72% (18/25) of cases had subgyral concordance with iEEG SOZ. Without segmentation, 60% (15/25) of cases had at least one area in 18F-FDG-PET scan concordant with iEEG SOZ at sublobar or higher levels, and 32% (8/25) with subgyral concordance. 83% (10/12) of seizure free patients had subgyral concordance on segmented 18F-FDG-PET. Both segmented and nonsegmented ictal-interictal SPECT perfusion clusters had 56% (14/25) of cases with at least sublobar concordance. Subgyral concordance was achieved by 28% (7/25) of segmented and 20% (5/25) of nonsegmented SPECTs.

DISCUSSION

Segmented 18F-FDG-PET scans frequently result in high correspondence to iEEG onset zones with localizations exactly concordant with iEEG SOZ- more than twice as often as without segmentation. Segmentation allows for the identification of small or subtle areas of hypometabolism that are often unappreciated or are obscured by normally hypometabolic white matter. Segmentation of ictal-interictal SPECT clusters did not significantly increase localization with iEEG SOZ over nonsegmented clusters.

Authors+Show Affiliations

Emory University School of Medicine, Atlanta, GA, USA;. Electronic address: kathryn.elkins@emory.edu.Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, USA. Electronic address: vmoncay@emory.edu.Departments of Pediatrics and Neurology, Emory University School of Medicine, Atlanta, GA, USA; Children's Healthcare of Atlanta, Atlanta, GA, USA. Electronic address: hyunmi.kim@emory.edu.Departments of Pediatrics and Neurology, Emory University School of Medicine, Atlanta, GA, USA; Children's Healthcare of Atlanta, Atlanta, GA, USA. Electronic address: lolson@emory.edu.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

28171851

Citation

Elkins, Kathryn C., et al. "Utility of Gray-matter Segmentation of ictal-Interictal Perfusion SPECT and Interictal 18F-FDG-PET in Medically Refractory Epilepsy." Epilepsy Research, vol. 130, 2017, pp. 93-100.
Elkins KC, Moncayo VM, Kim H, et al. Utility of gray-matter segmentation of ictal-Interictal perfusion SPECT and interictal 18F-FDG-PET in medically refractory epilepsy. Epilepsy Res. 2017;130:93-100.
Elkins, K. C., Moncayo, V. M., Kim, H., & Olson, L. D. (2017). Utility of gray-matter segmentation of ictal-Interictal perfusion SPECT and interictal 18F-FDG-PET in medically refractory epilepsy. Epilepsy Research, 130, pp. 93-100. doi:10.1016/j.eplepsyres.2017.01.009.
Elkins KC, et al. Utility of Gray-matter Segmentation of ictal-Interictal Perfusion SPECT and Interictal 18F-FDG-PET in Medically Refractory Epilepsy. Epilepsy Res. 2017;130:93-100. PubMed PMID: 28171851.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Utility of gray-matter segmentation of ictal-Interictal perfusion SPECT and interictal 18F-FDG-PET in medically refractory epilepsy. AU - Elkins,Kathryn C, AU - Moncayo,Valeria M, AU - Kim,Hyunmi, AU - Olson,Larry D, Y1 - 2017/01/30/ PY - 2016/09/16/received PY - 2017/01/01/revised PY - 2017/01/24/accepted PY - 2017/2/9/pubmed PY - 2018/1/6/medline PY - 2017/2/8/entrez KW - Intractable epilepsy KW - MRI KW - PET KW - SPECT KW - Segmentation SP - 93 EP - 100 JF - Epilepsy research JO - Epilepsy Res. VL - 130 N2 - PURPOSE: We present a method of gray-matter segmentation of functional neuroimaging for localization of seizure onset zone (SOZ) in epilepsy surgery. 18F-FDG-PET hypometabolism and ictal SPECT hyperperfusion may correspond to SOZ. We hypothesize that limiting functional images to gray matter improves identification of small, subtle, or obscure cortical volumes of 18F-FDG-PET hypometabolism and eliminates hyperperfused seizure propagation pathways within white matter in ictal perfusion SPECT. METHODS: Twenty-five adult and pediatric patients age 2-48 years with epilepsy surgery evaluations consisting of MRI, 18F-FDG-PET, ictal and interictal perfusion SPECT, and intracranial EEG (iEEG) monitoring were selected. MRI gray matter segmentation was used to identify cortical regions in coregistered 18F-FDG-PET and Ictal-Interictal SPECT Analysis by SPM (ISAS) as volumes of interest (VOI). VOIs in 18F-FDG-PET and SPECT perfusion clusters were compared to iEEG localization. The level of VOI concordance between two modalities was recorded as the same subgyrus (highest concordance), gyrus, sublobe, lobe, hemisphere, or no concordance. RESULTS: With segmentation, 84% (21/25) of cases had at least one area identified on 18F-FDG-PET scan concordant with iEEG SOZ at sublobar or higher levels, and 72% (18/25) of cases had subgyral concordance with iEEG SOZ. Without segmentation, 60% (15/25) of cases had at least one area in 18F-FDG-PET scan concordant with iEEG SOZ at sublobar or higher levels, and 32% (8/25) with subgyral concordance. 83% (10/12) of seizure free patients had subgyral concordance on segmented 18F-FDG-PET. Both segmented and nonsegmented ictal-interictal SPECT perfusion clusters had 56% (14/25) of cases with at least sublobar concordance. Subgyral concordance was achieved by 28% (7/25) of segmented and 20% (5/25) of nonsegmented SPECTs. DISCUSSION: Segmented 18F-FDG-PET scans frequently result in high correspondence to iEEG onset zones with localizations exactly concordant with iEEG SOZ- more than twice as often as without segmentation. Segmentation allows for the identification of small or subtle areas of hypometabolism that are often unappreciated or are obscured by normally hypometabolic white matter. Segmentation of ictal-interictal SPECT clusters did not significantly increase localization with iEEG SOZ over nonsegmented clusters. SN - 1872-6844 UR - https://www.unboundmedicine.com/medline/citation/28171851/Utility_of_gray_matter_segmentation_of_ictal_Interictal_perfusion_SPECT_and_interictal_18F_FDG_PET_in_medically_refractory_epilepsy_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0920-1211(17)30048-7 DB - PRIME DP - Unbound Medicine ER -