METABOLIC PATTERN OF NEOCORTICAL EPILEPSY QUANTIFIED BY STATISTICAL PROBABILISTIC ANATOMICAL MAPS
Abstract number :
1.225
Submission category :
Year :
2003
Submission ID :
2220
Source :
www.aesnet.org
Presentation date :
12/6/2003 12:00:00 AM
Published date :
Dec 1, 2003, 06:00 AM
Authors :
Kwang-Ki Kim, Sang Kun Lee, Chang Ho Yun, Jin-Chul Paeng, Dong-Soo Lee, Chun-Kee Chung Neurology, Seoul National University College of Medicine, Seoul, Korea; Nuclear Medicine, Seoul National University College of Medicine, Seoul, Korea; Neurosurgery, Seo
This study evaluated the patterns of metabolism in neocortical epilepsy, diagnosed by fluorodeoxyglucose positron emission tomography (FDG-PET), and tried to provide the basis of understanding the epileptic circuit, using a probabilistic atlas of the human brain (Statistical Probabilistic Anatomical Maps: SPAM).
Thirty-six frontal lobe epilepsy (FLE), 16 parietal lobe epilepsy (PLE), and 10 occipital lobe epilepsy (OLE) patients and 22 age-matched controls were spatially normalized to the average brain PET template of international consortium of brain mapping (ICBM). All neocortical epilepsy patients underwent invasive studies and focal neocortical resection. Counts from normalized PET images were multiplied by the probability from 98 volumes of interest (VOI) of SPAM. Asymmetric indexes (AI) reflecting the severity of hypometabolism or hypermetabolism were calculated by counts of selected all VOIs from SPAM images. The degree of hypometabolism or hypermetabolism was considered to be abnormal when AI was outside 3 standard deviation (p[lt]0.01) of those of normal controls. Ictal onset zone confirmed by invasive study was regarded as epileptic focus.
SPAM images showed abnormally lateralized hypometabolism including epileptic focus in twenty-two FLE, 11 PLE, and eight OLE patients. Localized hypometabolic VOIs consistent with epileptic focus were found in five FLE, one PLE, and one OLE patients. Ipsilateral subcortical hypermetabolic areas were found in 17 FLE, nine PLE, and five OLE patients. The frequent ipsilateral hypermetabolic structures were thalamus, subthalamic nucleus, putamen, and hippocampal formation. Variable other cortical VOIs were also ipsilaterally hypermetabolic.
Our results demonstrated that SPAM images could have a role in the diagnosis of neocortical epileptic focus. Ipsilateral hypermetabolic subcortical structures and other cortical areas suggest the disinhibition or the role of these structures in epilepsy. SPAM images can be used in the analysis of metabolic patterns of various epileptic syndromes.