In vivo hippocampal glucose metabolism in mesial temporal lobe epilepsy

Abstract

Although, decreased metabolism may occur in the absence of neuronal cell loss, hippocampal atrophy and presumed degree of neuronal cell loss appears to be a primary factor involved in the cause of decreased metabolism in epileptogenic hippocampi. Partial volume correction is recommended for optimal interpretation of hippocampal structure and function relationships.

The Hippocampus and Nucleus Accumbens as Potential Therapeutic Targets for Neurosurgical Intervention in Schizophrenia

“…In TLE, a long literature reports chronically low blood flow and decreased cerebral metabolism using SPECT, PET, and fMRI, with marked increases during seizures (reviewed in Duncan [51] ). Hypometabolism is most pronounced when the hippocampus is sclerotic and atrophied [52] . Hence, although the hippocampus does not appear overtly sclerotic in postmortem studies of schizophrenia, it is not implausible that excitotoxicity occurring within this region early in the course of the disorder may contribute to both the decrease in metabolic activity and postmortem histopathology associated with chronic schizophrenia.…”

Neuroimaging of the Epilepsies

“…The area of reduced metabolism in frontal lobe epilepsy may be much larger than the pathological abnormality. In contrast, however, the hypometabolic area may be restricted to the underlying lesion 117 . There have been three main patterns of hypometabolism described in patients with frontal lobe epilepsy: no abnormality; a discrete focal area of hypometabolism; diffuse widespread hypometabolism.…”

Partial Volume Correction Strategies in PET

“…Likewise, it has been demonstrated that reduced glucose metabolism measured by PET in dementia of the Alzheimer type is not simply an artifact caused by an increase in CSF space induced by atrophy but reflects a true metabolic reduction per gram of tissue [66]. In epileptic foci, also, hypometabolism is larger than a mere atrophy effect [67]. Assessment of the dopaminergic system with PET has shown that dopamine transporters are noticeably reduced in Lesh-Nyhan disease; PVC highlights this finding [68].…”