Temporal lobe hypometabolism on PET

Radtke, Rodney A.; Hanson, Michael; Hoffman, John M.; Crain, Barbara J.; Walczak, Thaddeus S.; Lewis, D. V.; Beam, Craig A.; Coleman, R. Edward; Friedman, Alon

doi:10.1212/wnl.43.6.1088

Cited by 138 publications

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“…In our population, lateralized hippocampal atrophy was strongly correlated with seizure-free outcome (class I), and relative focal TL hypometabolism with FDG-PET correlated with a good outcome (classes I and II). These results for MRI and FDG-PET are consistent with previous studies [5,[36][37][38]. T2 relaxometry also correlated with good outcome, but it appears to only reflect detection of the same patients as HV.…”

Section: Correlation With Outcomesupporting

confidence: 90%

Presurgical multimodality neuroimaging in electroencephalographic lateralized temporal lobe epilepsy

Knowlton

Laxer

Ende

et al. 1997

Annals of Neurology

127

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The purpose of this study was to compare 2-[ 18 F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET), hippocampal volumetry (HV), T2 relaxometry, and proton magnetic resonance spectroscopic imaging ( 1 H-MRSI) in the presurgical neuroimaging lateralization of patients with nonlesional, electroencephalogram (EEG)-defined unilateral temporal lobe epilepsy (TLE). Twenty-five patients were prospectively studied, along with age-matched controls. T2 relaxometry examinations were performed in 13 patients. Comparison of FDG-PET, HV, and 1 H-MRSI was possible in 23 patients. FDG-PET lateralized 87% of patients, HV 65%, N-acetyl aspartate (NAA)/(choline [Cho] + creatine [Cr]) 61%, and [NAA] 57%. Combined HV and NAA/(Cho + Cr) results lateralized 83% of the patients, a value similar to PET. Of 10 patients with normal magnetic resonance imaging (MRI) scans, 2 were lateralized with HV, 6 with FDG-PET, 4 with NAA/(Cho + Cr), and 3 with [NAA]. T2 relaxometry lateralized no patients without hippocampal atrophy. Bilateral abnormality was present in 29 to 33% of patients with 1 H-MRSI measures and 17% with HV. Only hippocampal atrophy correlated with postoperative seizure-free outcome. FDG-PET remains the most sensitive imaging method to correlate with EEG-lateralized TLE. Both FDG-PET and 1 H-MRSI can lateralize patients with normal MRI, but only the presence of relative unilateral hippocampal atrophy is predictive of seizure-free outcome. Bilaterally abnormal MRI and 1 H-MRSI measures do not preclude good surgical outcome.Multiple imaging methods are available to help lateralize temporal lobe epilepsy (TLE). To minimize the requirement for intracranial electrodes and to localize the epileptogenic zone with increased confidence, 2-[ 18 F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) and magnetic resonance imaging (MRI) are used to provide confirmatory localizing information. Relative temporal lobe (TL) hypometabolism on FDG-PET and hippocampal atrophy or prolonged T2 signal on MRI predict reliably lateralization of the epileptogenic temporal lobe [1][2][3][4][5]. Localized TL hypometabolism on FDG-PET is reported to be more sensitive than the detection of lateralized abnormality on MRI [3]; however, little has been published on the direct comparison of FDG-PET to advanced MRI and magnetic resonance spectroscopic imaging (MRSI) techniques. Gaillard and colleagues [6] compared FDG-PET with MRI-based hippocampal volumetry (HV) and showed that although FDG-PET was more Copyright © 1997 Patients and Methods Patients and Epilepsy EvaluationPatient selection commenced in April 1994 as part of a prospective imaging project with PET and MRSI at University of California, San Francisco (UCSF). Informed consent was obtained from all subjects according to guidelines of the UCSF Committee on Human Research. All surgical candidates suspected to have seizures arising from the TLs between April 1994 and June 1995 were screened for selection. After scalp-sphenoidal EEG/video telemetry, 36 patients were su...

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Section: Correlation With Outcomesupporting

confidence: 90%

Presurgical multimodality neuroimaging in electroencephalographic lateralized temporal lobe epilepsy

Knowlton

Laxer

Ende

et al. 1997

Annals of Neurology

127

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“…As early as 1987, Engel (1) noted that those patients studied before the introduction of the PET scan in the presurgical protocol at UCLA had a less favorable outcome. Others also reported that FDG-PET temporal hypometabolism (23,24), as well as MRI evidence of HS, correlates with a better outcome (25).…”

Section: Late Recurrencesmentioning

confidence: 97%

Longitudinal Follow‐Up in 145 Patients with Medically Refractory Temporal Lobe Epilepsy Treated Surgically Between 1984 and 1995

1999

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Summary: Purpose:There are few studies of prolonged longitudinal follow-up after temporal resections.Methods: We analyzed 145 consecutive patients with temporal lobe epilepsy treated surgically. Patients had a comprehensive presurgical evaluation, including video-EEG, psychometric testing, magnetic resonance imaging (MRI), singlephoton emission computed tomography (SPECT), intracarotid amobarbital procedure (IAP), and recently, volumetric head MRIs and F-fluorodeoxyglucose-positron emission tomography (FDG-PET) scans. Most had en bloc temporal resections, and a few had lesionectomies and resection of the epileptogenic zone. There was no surgical mortality. Longitudinal follow-up data of the seizure outcome were analyzed by actuarial analysis. Patients were followed up at 6 weeks, 3 months, 6 months, and then on a yearly basis. The mean follow-up was 5.6 years.Results: Sixty-six percent were seizure free at 1 year, 63% at 2 years, 60% at 5 years, and 55% at 10 years follow-up. Moreover, 85%, became seizure free for 2 2 at the time of last follow-up or had rare seizures. Patients who were seizure free for 1 and 2 years after surgery, had an 83% and 92% probability, respectively, of remaining seizure free at the time of last follow-up. Ninety-one percent of patients with small tumors and cavernous angiomas became seizure free compared with 69% of patients with hippocampal sclerosis.Conclusions: Actuarial analysis showed that the long-term surgical outcome of temporal lobe epilepsy remains favorable.

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“…Greater severity of the preoperative abnormality visualized by PET is associated with better postsurgical seizure control (58,59). …”

Section: Unilateral Mtsmentioning

confidence: 99%

Temporal Lobe Epilepsy: When Are Invasive Recordings Needed?

2000

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Summary:Temporal lobe epilepsy (TLE) is the most common type of medically intractable partial epilepsy amenable to surgery. In the majority of cases, the underlying pathology in temporal lobe epilepsy is mesial temporal sclerosis (MTS). Whereas historically invasive recordings were required for most epilepsy surgeries, indications have dramatically changed since the introduction of high-resolution MRI, which uncovers structural lesions in a high percentage of cases. No invasive recordings are required to perform a temporal lobectomy in patients with intractable epilepsy who have structural imaging suggesting unilateral MTS and concordant interictal and ictal surface EEG recordings, functional imaging, and clinical findings. Invasive testing is needed if there is evidence of bitemporal MTS on structural imaging and/or electrophysiologically, and additional information from functional imaging, neuropsychology, and the intracarotid amobarbital (Wada) test also does not help to lateralize the epileptogenic zone. Depth electrodes can be particularly helpful in this setting. However, no surgery is indicated, even without invasive recordings, if bitemporalindependent seizures are recorded by surface EEG and all additional testing is inconclusive. Other etiologies of TLE such as a tumor, vascular malformation, encephalomalacia, or congenital developmental abnormality account for about 30% of all patients who undergo epilepsy surgery. Epilepsy surgery is indicated after limited electrophysiologic investigations if neuroimaging and electrophysiology converge. However, approaches for resection in lesional temporal lobe epilepsy vary among centers. Completeness of resection is crucial and invasive recordings may be needed to guide the resection by mapping eloquent cortex and/or to determine the extent of the non-MRI-visible epileptogenic area. Specific approaches for the different pathologies are discussed because there is evidence that the relationship between the lesions visible on MRI and the epileptogenic zone varies among lesions of different pathologies, and therefore variable surgical strategies must be applied. Key Words: Temporal lobe-Epilepsy-Electrodes, implanted-Magnetic resonance imaging-Brain neoplasms. HISTORICAL PERSPECTIVES: INVASIVE RECORDINGS FOR EPILEPSY SURGERYThe pioneers of epilepsy surgery utilized clinical findings and seizure semiology to localize the epilepsy and to guide the neurosurgical intervention. This is illustrated by Victor Horsley's first neurosurgical intervention at Queens Square in 1886. The patient was a 22-year-old Scotsman who had a posttraumatic epilepsy. He had very frequent focal motor seizures characterized by a clear march. The diagnosis of "scar involving the hinder end of the superior frontal sulcus" was made according to the ictal semiology and the seizures stopped after surgical removal of the scar. Apart from semiologic analysis of the seizures, additional information was obtained by intraoperative cortical stimulations to reproduce the patient's seizure semiology and to ...

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Temporal lobe hypometabolism on PET

Cited by 138 publications

References 0 publications

Presurgical multimodality neuroimaging in electroencephalographic lateralized temporal lobe epilepsy

Presurgical multimodality neuroimaging in electroencephalographic lateralized temporal lobe epilepsy

Longitudinal Follow‐Up in 145 Patients with Medically Refractory Temporal Lobe Epilepsy Treated Surgically Between 1984 and 1995

Temporal Lobe Epilepsy: When Are Invasive Recordings Needed?

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