Time‐Course of Changes of SPECT, EEG, and Seizures in Temporal Lobe Epilepsy

Abstract

Purpose: Rccent reports havc shown that diagnostic imaging by SPECT is uscfiil in the assessment of cpilcptogcnic foci in the brain. We investigated the relationship betwcen the time‐course of SPECT, EEG, and seizure changes over 3‐ to 6‐year periods. Changes wcre correlatcd with therapeutic effect assessments and predicted prognoses. In our study, SPECT and EEG data werc recorded on the same day.Subjects: Subjects comprised 27 outpaticnts with temporal lobe epiIcpsy, mean age and duration of disease of 39.2 years and 23.2 years, respectively. Seizure frequencies were weekly in 4 subjects, monthly in 7, yearly in 6, no seizure for I to 4 years in 6, and no seizure for 2 3 years in 4. Methods: The early phase SPECT images were taken 30 minutes after intravcnous administretion of 1231‐IMP. Resting EEG was sub‐scqucntly recorded. SPECT scanning was performed on horizontal and coronary sections. Regional cerebral blood flow findings were coin‐parcd by visual inspection. Results: In 9 of the 14 subjects whose seizure severity improved over time, focal spikes wcrc tiot observed i n either examination, or disappeared by second examination. I n contrast, only 5 of the 14 subjects had normal basic EEG activity by the second examination. SPECT usually did not improve. Only I ol the 14 subjects whose seizure scvcrity improved over time showed normalized SPECT findings. No subjects with scizure severity rating “unchanged” or “worsened” showed normalized SPECT findings. SPECT normalized i n only I of the 16 subjects i n whoin focal spikes wcrc not observed in either cxamination, or disappeared by second examination. Conclusions: In our present study, improvement of seizures with treatment or over tiinc wits likely to be correlated with improvement in focal spikes but not with SPECT findings. This agrees with the report of Michihiro et al. in that focal spike disappearance preceded SPECT finding normalization during treatment.