Correlation of temporal lobe glucose metabolism with the Wada memory test

Purpose: The goal of the present study was to examine the relationship of F -18-fluorodeoxyglucose positron emission tomography (FDG-PET) and the Wada memory test in lateralizing memory dominance and epileptic focus. Methods: FDG-PET and the Wada test were performed in 18 patients with tempo ral lobe epilepsy (TLE). The asymmetry indices of FDG-PET (PET-AI) were cal culated in mesial, polar, anterolateral, midlateral, and posteroIateral reg ions of the temporal lobe, and those of Wada memory test (Wada-AI) were obt ained as well. Results: The Wada-AI was significantly correlated with PET-AT in mesial (r = 0.67, p = 0.003), polar (r = 0.55, p = 0.019), anterolateral (r = 0.55, p = 0.019), and midlateral (r = 0.51, p = 0.031) regions of the temporal lob e. However, after a linear regression analysis, PET-AI of only the mesial t emporal region was significantly correlated with Wada-AI (p = 0.008). Wada- AI could correctly lateralize the seizure focus in 90% of the left TLE and 75% of the right TLE patients. The PET-AT of the mesial temporal region sho wed the highest sensitivity of seizure lateralization (80% of left TLE and 87.5% of right TLE). PET-Al of other temporal regions had lower sensitiviti es (50-80% of left TLE, 20-75% of right TLE). One or two patients showed fa lse seizure lateralization by PET-AT on each temporal region. Conclusions: Although FDG-PET hypometabolism is observed at both mesial and lateral regions of the temporal lobe in mesial TLE, mesial temporal region appeared to be a dominant and leading area for lateralizing Wada memory do minance and epileptic focus.