Interictal 31P Metabolism in Temporal Lobe Epilepsy: Regional Differences within the Mesial Temporal Lobe.
Abstract number :
1.212
Submission category :
Year :
2001
Submission ID :
628
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
K.S. Firlik, M.D., Neurosurgery, Yale University School of Medicine, New Haven, CT; J.W. Pan, M.D., Ph.D., Neurology, Albert Einstein College of Medicine, Bronx, NY; D.D. Spencer, M.D., Neurosurgery, Yale University School of Medicine, New Haven, CT; H.P.
RATIONALE: Although previous reports have suggested that there are significant alterations in bioenergetics of the hippocampal formation in patients with temporal lobe epilepsy, little is known about the distribution of these changes. Therefore the goal of this study was to map the energetic changes seen in the amygdala, head of the hippocampus (pes) and hippocampal body in patients with mesial temporal lobe epilepsy (mTLE) in comparison to controls.
METHODS: Three dimenional 31P MR spectroscopic imaging was performed on a 4T MR system in 12 patients with mTLE who were being evaluated for temporal lobectomy, and 10 control subjects. Three regions of interest were selected bilaterally for each subject: amygdala, head of the hippocampus (pes), and body of the hippocampus. The exact position of the voxel center was selected using high resolution 3D T1-weighted images. 31P spectra were reconstructed from these exact locations using post-acquisition voxel shifting methods. The degree of bioenergetic impairment was assessed by calculating the Phosphocreatine to ATP ratio (PCr/ATP).
RESULTS: In controls, no significant difference was seen between the amygdala, pes and body from the left or right temporal lobes. Compared to controls, patients demonstrated significant decreases (p[lt]0.01) in PCr/ATP from the ipsilateral amygdala and pes (0.81[plusminus]0.16 and 0.84[plusminus]0.10 v. 0.97[plusminus]0.18 and 0.98[plusminus]0.17). The ipsilateral hippocampal body PCr/ATP ratio, 0.90[plusminus]0.07, was not significantly different from control 0.95[plusminus]0.11. However, a paired T-test comparison of the ipsilateral and contralateral hippocampal bodies within patients revealed a significant decrement in PCr/ATP in the ipsilateral hippocampal body (p[lt]0.01). Similar to that seen in the ipsilateral lobe, contralateral PCr/ATP was lowest in the amygdala, intermediate in the pes and highest in the body (Table).
CONCLUSIONS: As with previous results, the ipsilateral lobe was found to be more impaired energetically than the contralateral lobe. Bioenergetic impairment in the TLE patients demonstrates a regional pattern with Ipsi : amygdala[lt]pes[lt]body [lt] Contra : amygdala[lt]pes[lt]body. This is consistent with the belief that the degree of damage in mTLE is more extensive in the anterior structures.[table]
Support: National Institutes of Health P01-NS-39092.