¹⁸F-fluorodeoxyglucose and ¹⁸F-flumazenil positron emission tomography in patients with refractory epilepsy

Abstract

BackgroundEpilepsy is a neurological disorder characterized by epileptic seizures as a result of excessive neuronal activity in the brain. Approximately 65 million people worldwide suffer from epilepsy; 20–40% of them are refractory to medication therapy. Early detection of disease is crucial in the management of patients with epilepsy. Correct localization of the ictal onset zone is associated with a better surgical outcome. The modern non-invasive techniques used for structural-functional localization of the seizure focus includes electroencephalography (EEG) monitoring, magnetic resonance imaging (MRI), single photon emission tomography/computed tomography (SPECT/CT) and positron emission tomography/computed tomography (PET/CT). PET/CT can predict surgical outcome in patients with refractory epilepsy. The aim of the article is to review the current role of routinely used tracer 2-deoxy-2-[18F]fluoro-D-glucose (18F-FDG) as well as non routinely used 18F-Flumazenil (18F-FMZ) tracers PET/CT in patients with refractory epilepsy.ConclusionsFunctional information delivered by PET and the morphologic information delivered by CT or MRI are essential in presurgical evaluation of epilepsy. Nowadays 18F-FDG PET/CT is a routinely performed imaging modality in localization of the ictal onset zone in patients with refractory epilepsy who are unresponsive to medication therapy. Unfortunately, 18F-FDG is not an ideal PET tracer regarding the management of patients with epilepsy: areas of glucose hypometabolism do not correlate precisely with the proven degree of change within hippocampal sclerosis, as observed by histopathology or MRI. Benzodiazepine-receptor imaging is a promising alternative in nuclear medicine imaging of epileptogenic focus. The use of 11C-FMZ in clinical practice has been limited by its short half-life and necessitating an on-site cyclotron for production. Therefore, 18F-FMZ might be established as one of the tracers of choice for patients with refractory epilepsy because of better sensitivity and anatomical resolution.

Neuro-PET – ein Update

“…In einer histopathologischen Korrelation wurde allerdings gezeigt, dass die Areale mit vermindertem Glucosemetabolismus nicht exakt mit dem Ausmaß der Hippocampussklerose oder dem MRT korrelieren [51]. Die Darstellung des Benzodiazepin-Rezeptors bietet hierzu im Vergleich eine bessere Ortsauflösung [51].…”

“…In einer histopathologischen Korrelation wurde allerdings gezeigt, dass die Areale mit vermindertem Glucosemetabolismus nicht exakt mit dem Ausmaß der Hippocampussklerose oder dem MRT korrelieren [51]. Die Darstellung des Benzodiazepin-Rezeptors bietet hierzu im Vergleich eine bessere Ortsauflösung [51]. Die ersten entwickelten Tracer, insbesondere 11 C-Flumazenil, fanden aufgrund der schlechten Verfügbarkeit durch die kurze Halbwertszeit von 11 C keinen Einzug in die klinische Routine [52].…”

“…Die ersten entwickelten Tracer, insbesondere 11 C-Flumazenil, fanden aufgrund der schlechten Verfügbarkeit durch die kurze Halbwertszeit von 11 C keinen Einzug in die klinische Routine [52]. Trotz Entwicklung weiterer Benzodiazepin-Rezeptor-Liganden mit 18 F [53] werden diese nur an ausgewählten Zentren angeboten und sind komplexen Fragestellungen im Rahmen von therapierefraktären Epilepsieformen vorbehalten [51].…”

Added Value of NeuroGam Software Analysis in Single Photon Emission Computed Tomography Localization Diagnosis of Epilepsy in Interictal Stage

“…PET might have an excellent prospective and applicative value in the study of epilepsy; however, there are high requirements for the preparation of positron radiopharmaceuticals, and the examination is cost-ineffective, which limits its routine clinical application [ 6 , 7 ].…”

Estudo do metabolismo energético mitocondrial e sua relação com as crises epiléticas em Wistar audiogenic rats (WAR)

“…Por meio da avaliação por emissão de pósitron por 18F-fluorodesoxiglicose, foram relatados hipermetabolismo glicolítico no foco epilético em pacientes com epilepsia refratária (HODOLIC et al, 2016;ZIMMER et al, 2017). Em momentos de despolarização há aumento de 5 vezes nas concentrações de glutamato na fenda sináptica, o que retorna a concentração normal após 10 milissegundos (DZUBAY;JAHR, 1999;KATAGIRI et al, 2001).…”