THE CAUSE OF EXTRA-TEMPORAL HYPOMETABOLISM IN MESIAL TEMPORAL LOBE EPILEPSY: ATROPHY AND HYPOMETABOLISM OF HIPPOCAMPUS
Abstract number :
3.174
Submission category :
Year :
2002
Submission ID :
3022
Source :
www.aesnet.org
Presentation date :
12/7/2002 12:00:00 AM
Published date :
Dec 1, 2002, 06:00 AM
Authors :
Eun Yeon Joo, Eun Kyung Lee, Woo Suk Tae, Dae Won Seo, Hoowon Kim, Seung Bong Hong. Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea; Neuroimaging Laboratory of Neurology, Samsung Medical Center, Seoul, Korea; Ne
RATIONALE: The mechanism of extra-temporal PET hypometabolism in mesial temporal lobe epilepsy (mTLE) is still controversial. We performed this study to find whether the degrees of hippocampal atrophy and hypometabolism are related to the presence of extra-temporal hypometabolism.
METHODS: Sixteen unilateral mTLE patients (22.6[plusminus]5.2 years) underwent 18F-FDG PET and volumetric SPGR MRI with 1.6 mm thickness. Subjects were divided into two groups; 1) PET hypometabolism in only temporal lobe (TH: temporal hypometabolism, age: 28.28[plusminus]10.41 years, seizure history: 14.71[plusminus]8.59 years) and 2) hypometabolism in both temporal lobe and extra-temporal region (ETH: temporal and extra-temporal hypometabolism, age: 21.66 [plusminus] 6.65 years, seizure history: 8.77[plusminus]4.08 years) by visual inspection. The volumes of hippocampus (HV) and whole cerebrum (WCV) were measured by a semi-automated and manual drawing method. Mean PET metabolism of hippocampus (PET-hipp) was measured by PET-MRI co-registration and adjusting the ROI of hippocampus from SPGR MRI. HV was normalized with being divided by WCV of each patient, and PET-hipp was normalized with being divided by the mean PET metabolism of the non-epileptic hemisphere of each patient. Then asymmetry indices of HV and PET-hipp were calculated by the value of epileptic hippocampus / the value of non-epileptic hippocampus. Statistical analysis was performed with Mann-Whitney U test.
RESULTS: There were no significant differences in WCV (TH: 1,030.3 [plusminus]66.8 cm3, ETH: 1,004.3[plusminus] 61.9 cm3, p=0.491) and normalized HV of non-epileptic side (TH: 2.92[plusminus]0.43 cm3, ETH: 2.86[plusminus]0.55 cm3, p=0.958) between TH and ETH groups. Normalized HV (TH: 2.07[plusminus]0.77 cm3, ETH: 1.48[plusminus]0.34 cm3, p=0.062) of epileptic side and the asymmetry index of HV (TH: 0.71[plusminus]0.38, ETH: 0.46[plusminus]0.11, p=0.063) appeared to be smaller in ETH. The asymmetry index (TH: 0.86[plusminus]0.24, ETH: 0.68[plusminus]0.098, p=0.0195) and the normalized value of PET-hipp (TH: 15.2[plusminus]2.07, ETH: 12.6[plusminus]2.72, p=0.025) were significantly lower in ETH.
CONCLUSIONS: Epileptic hippocampus of patients with ETH showed significantly lower glucose metabolism and appeared more atrophic than that of patients with TH. This result indicates that extra-temporal hypometabolism in mTLE is related to a greater degree of hippocampal damage.
[Supported by: the Korean Ministry of Science and Technology under the National Research Laboratory (NRL) program (2000-N-NL-01-C-157).]