[11C]flumazenil positron emission tomography visualizes frontal epileptogenic regions.
ABSTRACT Presently available noninvasive methods correctly localize epileptogenic regions in only approximately 50% of patients with frontal lobe epilepsy (FLE). Earlier studies have shown that temporal lobe epileptogenic regions may be identified readily by positron emission tomography (PET) measurements of regional benzodiazepine (BZD) receptor binding. We tested the specific applicability of this method in patients with FLE. Six patients with frontal partial seizures and 7 healthy men were investigated with PET and the BZD receptor ligand [11C]flumazenil. All patients had magnetic resonance (MR) brain scans. The independent assessment of seizure-onset region was based on seizure semiology, intra- and extracranial EEG and, in 4 cases, also on [18F]fluorodeoxyglucose (FDG)-PET. The epileptic focus/seizure-generating region was correctly identified by [11C]flumazenil PET in all patients. This region was characterized by a significant reduction in BZD receptor density. The area with reduced BZD receptor density was better delimited than the corresponding hypometabolic region, which was observed in 50% of patients investigated with [18F]FDG-PET. MRI was normal in 5 patients. Visualization of BZD receptors with [11C]flumazenil PET appears to be a promising approach for noninvasive identification of frontal lobe epileptogenic regions.
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ABSTRACT: Molecular imaging with ictal and interictal single-photon emission computed tomography (SPECT) as well as positron emission tomography (PET) rank among the established functional imaging tests for the presurgical evaluation of epileptic onset zone in patients with intractable partial epilepsy. In temporal lobe epilepsy the sensitivity of these methods was shown to be excellent, in particular if a multimodal platform is used, which combines the functional imaging with the additional morphological information of magnetic resonance imaging (MRI), but was lower in extra temporal lobe epilepsy. Functional imaging with SPECT and PET reflects seizure related changes of cerebral perfusion, glucose-metabolism and neuroreceptor status. In this review the usefulness of SPECT and PET imaging in clinical routine in epilepsy as well as the role of different neuroreceptor PET-tracer, which were used in epilepsy are discussed. The use of perfusion SPECT tracer allows the investigation of ictal activations, but the low temporal resolution of ictal perfusion SPECT often results in the detection of both the ictal onset zone as well as the propagation pathways, an area that has not always need to be resected in order to render a patient seizure free. The additional use of interictal PET with fluorine-18 fluorodeoxyglucose which measures regional cerebral metabolism or interictal perfusion SPECT enhance the informational value of ictal SPECT and were shown to be important tools to better define the ictal onset and surround inhibition zones. In recent years PET imaging of different cerebral neuroreceptor-systems inter alia GABA(A) receptors, serotonin receptors (5-HT(1A)), opioid receptors as well as dopamine receptors was used to investigate the neurochemical basis of epilepsy, the role of these neurotransmitters for the epileptogenesis as well as the spread of epileptic activity during seizures and partially entered in clinical routine. Currently some of these radioligands are also used to investigate new treatment approaches.Epilepsy & Behavior 03/2009; 15(1):50-5. · 2.34 Impact Factor
Article: PET in seizure disorders.[show abstract] [hide abstract]
ABSTRACT: PET imaging has been widely used in the evaluation and management of patients with seizure disorders. The ability of PET to measure cerebral function is ideal for studying the neurophysiologic correlates of seizure activity during both ictal and interictal states. PET imaging is also valuable for evaluating patients before surgical interventions to determine the best surgical method and maximize outcomes. PET will continue to play a major role, not only in the clinical arena, but also in investigating the pathogenesis and treatment of various seizure disorders.Radiologic Clinics of North America 02/2005; 43(1):79-92. · 2.59 Impact Factor
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ABSTRACT: The clinical usefulness of nuclear medicine in the preoperative evaluation of epilepsy is highlighted with regard to non-lesional temporal lobe epilepsy, extratemporal epilepsy, bitemporal interictal epileptiform discharges (IEDs) and in dual pathology and cortical dysgenesis. Ictal single photon emission computed tomography (SPECT) shows good sensitivities in the correct lateralization of an electroencephalogram-defined epileptic focus in lesional and, to a lesser extent, non-lesional epilepsy. Positron emission tomography (PET) using 18F-fluorodeoxyglucose or 11C-flumazenil gives a good detection rate of the seizure onset zone in non-lesional cases and extratemporal epilepsy. The investigation of patients with bitemporal IEDs can confirm the existence of bitemporal seizure onset. For patients with a dual pathology or cortical dysgenesis nuclear medicine offers the opportunity to delineate the existence or extension of abnormalities possibly responsible for the seizure disorder.Nuclear Medicine Communications 08/2001; 22(7):835-40. · 1.40 Impact Factor