The Value Of Imaging Techniques In Temporal Lobe Epilepsy Study

Epilepsy is a common disease, about 20-30% of patients were intractable in terms of response to medication. Temporal lobe epilepsy(TLE) is one cause of intractable epilepsy commonly seen. Now the consensus has been reached that the intractable TLE should be treated with surgery as soon as possible. Whether or not the epilepsy focus could be located precisely has a close relationship with surgery outcome The use of rational methods can improve dignosis rate of TLE and decrease cost-effect ratio in treatment. In order to provide scientific reference for clinical work, we compare the advantages and disadvantages of different neuroimaging techniques such as MRI,¹H-MRS,³¹p-MRS,FAIR,PET and SPECT in lateralization of TLE.1. One hundred and forty seven patients, aged 16～62, with clinically and EEG confirmed TLE were entered into our study. These patients were divided into the hippocampus sclerosis group and crypotogenic group according to MRI appearance. And also these patients were divided into unilateral and bilateral TLE according to clinical EEG-based evaluation.2. Head and hippocampus MRI: hippocampus, amygdala and entorhinal cortex were assessed by MRI volumetric measurement and visual inspection.3. ¹H-MRS: Single voxel spectroscopy and 2D MRS were performed in region. The ratio of NAA, Cho and mI were compared between different groups, ¹H-MRS results were correlated and compared with clinical, MRI, ³¹p-MRS and PET results.4. ³¹p-MRS: The changes ofPcr,γ-ATP,PME,PDE of bilateral temporal lobe in TLE were compared between different groups and were correlated with ¹H-MRS and PET results.5. FAIR: The changes of rCBF in hippocampus,lateral temporal lobe and parietal lobe were compared between different groups and were correlated with PET and SPECT. 1. The volume of hippocampus and entorhinal cortex of TLE were significantly lower than the control group(p＜0.05). The volume of amygdale were not significantly between the TLE group and control group.2. The ipsilateral volume of hippocampus in unilateral TLE were significantly lower than the contralateral side(p＜0.05), while there was no significant difference in bilateral TLE;3. In crypotogenic TLE the volume of the ipsilateral hippocampus were significantly lowerer than the contralateral hippocampus while the volume of the ipsilateral entorhinal cortex was not significantly lowerer than the contralateral entorhinal cortex. In TLE with hippocarnpal sclerosis the volume of the ipsilateral hippocampus and entorhinal cortex were significantly lowerer than the contralateral.4. Ipsilateral NAA in TLE patients were significantly lower than the contralateral NAA and the bilateral NAA in control group(p＜0.05). There were no statistical difference between TLE group and control group in the ratio of Cho and mI.5. The bilateral asymmetry of NAA in unilateral group was more significant than bilateral TLE;6. The positive lateralization rate of NAA reduction were 70.45% and 50% in the HS and the cryptogenic TLE respectively. The concordance between ¹H-MRS(NAA) and EEG were 66% and 50% respectively in these two groups.7. The degree of NAA reduction was related with the frequency of simple partial seizures, age of seizuer onset, duration of seizuer and history of febrile convulsions.8. The results of 2D-MRS in TLE showed that NAA reduction were more significant in ipsilateral hippocampus, amygdala and lateral temporal lobe than the contralateral.9. The height of metabolite peaks in ³¹P-MRS show no statistical difference between the ipsilateral side and contralateral sidesin TLE.10. In HS group the PME/Pi and PDE/Pi ratios of area under peaks ipsilateral to the hippocampal sclersis were significantly lower than the control group (p＜0.05).11. The positive lateralization rate of ³¹P-MRS in TLE was 30%. 12. The FAIR results showed that the rCBF of bilateral hippocampus was asymmetric.13. The comparative analysis between PET and MRI showed that PET could provided lateralization information for MRI negative patients.The comparative analysis between PET and ¹H-MRS(NAA) showed that the lateralization rate of TLE were 60% and 85% for PET and ¹H-MRS(NAA) respectively.1. The MRI volumetric measurements in the hippocampus and entorhinal cortex may provide information about the TLE lateralizion, while the significance of amygdala MRI volumetric measurements for TLE lateralizion were not found in this research.2. ¹H-MRS(NAA)may provide TLE lateralizion information, Cho and mI may not provide the lateralizion information;3. The volumetric change of hippocampus and neuronal function of unilateral TLE patients were different from the bilateral TLE patients.4. The change of the volume of hippocampus and neuron function of HS were more significant than the crypotogenic TLE.5. The positive rate of ³¹p-MRS was lower than MRI, ¹H-MRS(NAA) and PET in lateralizing TLE.6. The sensitivity and specificity of FAIR was lower than PET and SPECT.7. The sensitivity of PET was high in lateralizing TLE, especially for MRI negative patients, PET can provide additional lateralization information.8. The volumetric changes of mesial temporal lobe structure and neural function in TLE were related and many clinical factors.