OUTCOME OF TEMPORAL-LOBE EPILEPSY SURGERY PREDICTED BY STATISTICAL PARAMETRIC PET IMAGING

PET is useful in the presurgical evaluation of temporal robe epilepsy. The purpose of this retrospective study is to assess the clinical use of statistical parametric imaging in predicting surgical outcome. Met hods: Interictal (18)FDG-PET scans in 17 patients with surgically-trea ted temporal lobe epilepsy (Group A = 13 seizure-free, group B = 4 not seizure-free at 6 mo) were transformed into statistical parametric im aging, with each pixel representing a z-score value by using the mean and s.d. of count distribution in each individual patient, for both vi sual and quantitative analysis. Results: Mean z-scores were significan tly more negative in anterolateral (AL) and mesial (M) regions on the operated side than the nonoperated side in group A (AL: p < 0.00005, M : p = 0.0097), but not in group B (AL: p = 0.46, M. p = 0.08). Statist ical parametric imaging correctly lateralized 16 out of 17 patients. O nly the AL region, however, was significant in predicting surgical out come (F = 29.03, p < 0.00005). Using a cut-off z-score value of -1.5, statistical parametric imaging correctly classified 92% of temporal ro bes from group A and 88% of those from Group B. Conclusion: The prelim inary results indicate that statistical parametric imaging provides bo th clinically useful information for lateralization in temporal lobe e pilepsy and a reliable predictive indicator of clinical outcome follow ing surgical treatment.