Objective: To evaluate and compare the role of (1)H MRS, PET and EEG in lateralization diagnosis (LD) of temporal lobe epilepsy (TLE).
Methods: 15 patients with intractable TLE verified by operation and pathology were studied. Before unilateral anterior temporal lobectomy, (1)H MRS, PET and EEG were performed for the LD of TLE. The diagnostic value of (1)H MRS, PET and EEG was compared based on the pathology and follow-up results.
Results: With video scalp EEG monitoring, the focus was localized in one temporal lobe for 13 patients among which 5 had abnormal waves conducted to the contralateral lobe. Intracranial EEG was performed for other 2 patients because scalp EEG failed to make the LD. Ultimately, partial temporal lobectomy was performed in all patients based on LD by scalp EEG or intracranial EEG. The pathological findings of operation specimens showed various degree of hippocampal sclerosis. The surgery was proved to be effective by follow-ups of all 15 patients, with their conditions controlled in 12 cases and better in two. EEG succeeded to make correct LD in all cases. (1)H MRS made correct LD in 12 cases (80%) and incorrect LD in 1 case, and failed to made LD in 2 cases. Five bilateral abnormalities (33%) were found by MRS. FDG-PET made correct LD in 14 cases (93%) and incorrect LD in 1 case, and found two cases with bilateral abnormalities (13%).
Conclusion: (1)H MRS, PET and EEG are all effective means in LD of TLE. Up to now, scalp EEG is the first choice and continuous video EEG monitoring has its own unique advantage. As a kind of simple, noninvasive and objective method, MRS can be used as a routine examination in conjunction with conventional MRI. Although PET is quite sensitive, it is expensive and has a number of limitations. So it can be used depending on the affordability of patients or diagnostic need. Combination of MRI, MRS, PET and scalp EEG may improve the reliability of the LD compared with use of any one of them alone. While the results of these methods are controversial, intracranial EEG is inevitable.