The Role of Ictal SPECT in Preoperative Lateralization of Epileptogenic Focus: A Comparison of Results with EEG and MRI Findings
F. İrsel TEZER1, Serap SAYGI2, Eser EL ERGÜN3, Neşe DERİCİOĞLU4, Bilge VOLKAN5, Kader KARLI OĞUZ6, Abdurrahman CİĞER4, Işıl SAATÇİ6, Belkıs ERBAŞ8
1Hacettepe Üniversitesi Tıp Fakültesi Nöroloji ABD, ANKARA
2Hacettepe Üniversitesi Tıp Fakültesi Nöroloji ABD, ANKARA
3Hacettepe Üniversitesi Tıp Fakültesi Nükleer Tıp, Anabilim Dalı, ANKARA
4Hacettepe Üniversitesi Nörolojik ve Psikiyatrik Bilimler Enstitüsü, ANKARA
5Hacettepe Üniversitesi Tıp Fakültesi Hacettepe Üniversitesi Tıp Fakültesi Nükleer Tıp, Anabilim Dalı, ANKARA
6Hacettepe Üniversitesi Tıp Fakültesi Radyoloji Anabilim Dalı, ANKARA
7Hacettepe Üniversitesi Tıp Fakültesi Radyoloji Anabilim Dalı, ANKARA
8Hacettepe Üniversitesi Tıp Fakültesi Hacettepe Üniversitesi Tıp Fakültesi Nükleer Tıp, Anabilim Dalı, ANKARA
Keywords: ictal SPECT, facal seizure, electroencephalography (EEG), magnetic resonance imaging (MRI)
Abstract
Background and Objective: The roles of MRI, SPECT and PET in preoperative localization/lateralization of epileptogenic foci are well known. lctal SPECT is known to be mor e sensitive in lateralization. In this study, ictal SPECT findings were analyzed in patients with facal seizures. The results were compared with EEG and MRI findings.Material and Methods: All the data of patients who had ictal SPECT with Tc-HMPAO during the last 10 years were retrospectively evaluated. Finally, patients who had well documented clinical records, MRI, ictal and interictal EEG, semiological findings and those who had clinical or electrophysiological seizures with focal onset during injection were included in the study. Findings: Sixteen patients (10M, 6F; mean age 25±8 years) were investigated. Nine patients had extratemporal seizures, 5 had temporal seizures and 2 had both temporal and extratemporal seizures. Mean intravenous injection time ofTc-99m HMPAO after seizure onset was 34.5 seconds. lctal SPECT findings were compared with interictal EEG, ictal EEG and MRI findings with respect to lateralization of the epileptogenic area. lctal SPECT findings were concordant with interictal EEG in 69% (11/16), ictal EEG in 75% (12/16) and MRI in 37.5% (6/16) of the patients, respectively. Nine patients were reported to have normal MRI initially. Due to lateralized findings in ictal SPECT, MRI was repeated in five patients and disclosed cerebral lesions in concordance with ictal SPECT in 4 of them. Therefore, the concordance rate of MRI and ictal SPECT for the lateralisation of epileptogenic area was increased to 62.5%. lctal SPECT was normal in 3 patients. All had clinically extratemporal seizures and the duration of these were shorter than 20 seconds. Conclusion: Ictal SPECT and ictal EEG disclosed high concordan ce rate in patients with normal or insufficient initial MRI findings,. Additionally, the reliability of ictal SPECT in patients with temporal lobe seizures was higher tha n patients with extratemporal lobe seizures with short seizure duration.