MEASUREMENT OF TEMPORAL ASYMMETRIES OF GLUCOSE CONSUMPTION USING LINEAR PROFILES - REPRODUCIBILITY AND COMPARISON WITH VISUAL ANALYSIS

Aim: One approach to regionally analyze temporal glucose consumption c onsists in drawing linear profiles over the maximal values measured in the temporal cortical ribbon. The aim of our study was to test the re producibility of this method and to compare its diagnostic performance to that of visual analysis in patients with complex partial seizures (CPS). Methods: Regional cerebral glucose consumption (rCMRGlc) was me asured interictally in 25 CPS patients and 10 controls using F-18-deox yglucose and the positron emission tomography (PET) camera ECAT EXACT 47. The PET scans were visually analyzed for the occurrence of unilate ral temporal hypometabolism. Furthermore, rCMRGlc was quantified on si x contiguous coronal planes by manually tracing maximal values oi temp oral glucose consumption, thus creating line profiles of temporal gluc ose consumption for each side. Indices of asymmetry (ASY) were then ca lculated from these line profiles in four temporal regions and compare d to the corresponding 95% confidence intervals of the control data. A ll analyses were performed by two observers independently from each ot her and without knowledge of the clinical findings. Results: The agree ment between the two observers with regard to focus lateralization was 96% (kappa = 0.93) on visual analysis and 100% (kappa = i) on quantit ative analysis. There was an excellent agreement with regard to focus lateralization between visual and quantitative evaluation (kappa = 0.8 ). Conclusion: Quantitation of local temporal rCMRGlc by using linear profile analysis is highly reproducible; for the lateralization of epi leptogenic foci, however, this method does not possess significant adv antages over the visual evaluation of the scans.