'MRI-negative PET-positive' temporal lobe epilepsy (TLE) and mesial TLE differ with quantitative MRI and PET: a case control study

Background: \u27MRI negative PET positive temporal lobe epilepsy\u27 represents a substantial minority of temporal lobe epilepsy (TLE). Clinicopathological and qualitative imaging differences from mesial temporal lobe epilepsy are reported. We aimed to compare TLE with hippocampal sclerosis (HS+ve) and non lesional TLE without HS (HS-ve) on MRI, with respect to quantitative FDG-PET and MRI measures.Methods: 30 consecutive HS-ve patients with well-lateralised EEG were compared with 30 age- and sex-matched HS+ve patients with well-lateralised EEG. Cerebral, cortical lobar and hippocampal volumetric and co-registered FDG-PET metabolic analyses were performed.Results: There was no difference in whole brain, cerebral or cerebral cortical volumes. Both groups showed marginally smaller cerebral volumes ipsilateral to epileptogenic side (HS-ve 0.99, p = 0.02, HS+ve 0.98, p &lt; 0.001). In HS+ve, the ratio of epileptogenic cerebrum to whole brain volume was less (p = 0.02); the ratio of epileptogenic cerebral cortex to whole brain in the HS+ve group approached significance (p = 0.06). Relative volume deficits were seen in HS+ve in insular and temporal lobes. Both groups showed marked ipsilateral hypometabolism (p &lt; 0.001), most marked in temporal cortex. Mean hypointensity was more marked in epileptogenic-to-contralateral hippocampus in HS+ve (ratio: 0.86 vs 0.95, p &lt; 0.001). The mean FDG-PET ratio of ipsilateral to contralateral cerebral cortex however was low in both groups (ratio: HS-ve 0.97, p &lt; 0.0001; HS+ve 0.98, p = 0.003), and more marked in HS-ve across all lobes except insula.Conclusion: Overall, HS+ve patients showed more hippocampal, but also marginally more ipsilateral cerebral and cerebrocortical atrophy, greater ipsilateral hippocampal hypometabolism but similar ipsilateral cerebral cortical hypometabolism, confirming structural and functional differences between these groups.<br /

Blood lead levels of traffic- and gasoline-exposed professionals in the city of Athens

During the past 10 y, blood lead levels in the population of Athens, Greece, have decreased steadily. This decrease has paralleled the reduction of tetraethyl lead in gasoline and the introduction of unleaded fuel. Blood lead levels and other parameters were studied in 42 gas-station employees, 47 taxi drivers, 47 bus drivers, and 36 controls, all of whom worked in Athens. The blood lead levels did not differ significantly among the four groups (5.64 +/- 1.7 mu g/dl, 5.96 +/- 1.7 mu g/dl, 5.88 +/- 1.3 mu g/dl, and 5.76 +/- 1.7 mu g/dl, respectively). Glutamic-oxaloacetic transaminase (i.e., aspartate aminotransferase) and glutamic-pyruvic transaminase (i.e., alanine aminotransferase) were elevated in gas-station employees, and the former was elevated in taxi drivers, Gas-station employees who smoked had higher blood lead levels than their nonsmoking counterparts. The absence of any difference in the blood lead levels of individuals for whom physical examinations were either normal or abnormal suggests that either lead was not the cause of increased blood lead levels or that its contribution may have been important in the past

Cortical atrophy detected by computed tomography in gasoline station attendants

Background: To evaluate the contribution of leaded gasoline in the presence of abnormal calcifications or cortical atrophy seen in computed tomographies (CT) of the head of occupationally exposed professionals working in the centre of Athens. Methods: One hundred and twenty-two head CTs from gas station employees and traffic-exposed professionals (taxi and bus drivers) were analyzed for evidence of cortical atrophy or abnormal calcifications. Blood lead level (BLL) of these lead occupationally exposed groups was compared with 37 non-exposed subjects. Results: All three occupationally exposed-to-lead groups had similar blood lead levels compared to the non-exposed group and within the currently accepted norms for lead. No abnormal calcifications were found. Cortical atrophy was more frequently seen in the gas station employees group using univariate and multivariate analysis. In the logistic regression model gas station employment had a stronger impact in developing cortical atrophy [odds ratio of 6.43 (1.46-28.3, 95% CI)] than BLL [odds ratio of 1.4 (1.01-2.05, 95% CI)]. Conclusions: These results show that employment in gasoline stations may be associated with detectable cortical atrophy in imaging studies and suggest the contribution of a leaded gasoline to its development. (C) 1999 Elsevier Science B.V. All rights reserved