PET AND SPECT IN MEDICALLY NONREFRACTORY COMPLEX PARTIAL SEIZURES - TEMPORAL ASYMMETRIES OF GLUCOSE CONSUMPTION, BENZODIAZEPINE RECEPTOR DENSITY, AND BLOOD-FLOW

Aim: In contrast to medically refractory complex partial seizures (CPS ), only limited knowledge exists on cerebral perfusion and metabolism in medically non-refractory CPS. The aim of this study was to investig ate the frequency of temporal asymmetries in regional cerebral glucose consumption (rCMRGlc), regional cerebral blood flow (rCBF), and regio nal cerebral benzodiazepine receptor density (BRD) in this group of pa tients. Methods: The study included 49 patients with medically non-ref ractory cryptogenic CPS (age: 36.0 +/- 16.1 years). rCMRGlc was studie d with F-18-FDG-PET (FDG), rCBF with Tc-99m-ECD-SPECT (ECD), and BRD w ith I-123-iomazenil-SPECT (IMZ). All studies were performed interictal ly and within four weeks in each patient. Duration of epilepsy ranged from 0.1 to 42 years (median 4.0 years). SPECT was performed with the triple-headed SPECT camera Multispect 3, PET with the PET camera ECAT EXACT 47. Using linear profiles, glucose consumption, as well as uptak e of ECD and IMZ, were measured in four temporal regions of interest ( ROIs), and asymmetry indices were calculated (ASY). The results were c ompared to 95% confidence intervals determined in control subjects. Re sults: Thirty-five of the 49 (71%) patients had at least one significa ntly elevated ASY; temporal rCMRGlc was asymmetrical in 41% of the pat ients, temporal BRD in 29%, and temporal rCBF in 24%. One patient had an asymmetry of ail three variables, two of temporal rCMRGlc and BRD, three of temporal rCMRGlc and rCBF, and another four of rCBF and BRD. Fourteen patients had an isolated temporal asymmetry in rCMRGlc, seven in BRD, and four in rCBF. A discrepancy in lateralization between the three modalities was not observed. Conclusion: The majority of patien ts with medically non-refractory CPS have focal abnormalities of blood flow and metabolism in their temporal lobe. in this group of patients , FDG-PET demonstrates abnormalities with the highest frequency of the three modalities studied, followed by IMZ-SPECT, and ECD-SPECT.