PET and SPECT in Medically Non-Refractory Complex Partial Seizures

Zusammenfassung

Ziel: Im Gegensatz zu den medikamentös-refraktären komplex-fokalen Epilepsien (CPS) wurden zerebrale Perfusion und Metabolismus bei Patienten mit nichtrefraktären Epilepsien kaum untersucht. Ziel dieser Studie war die Untersuchung der Häufigkeit temporaler Asymmetrien des regionalen zerebralen Glukoseverbrauchs (rCMRGIc), der regionalen zerebralen Perfusion (rCBF) und der regionalen zerebralen Benzodi- azepin-Rezeptordichte (BRD) bei dieser Patientengruppe. Methoden: Es wurden 49 Patienten mit medikamentös-nichtrefraktären, kryptogenen CPS untersucht (Alter: 36,0 ± 16,1 Jahre). Der rCMRGIc wurde mit F-18-FDG-PET (FDG), der rCBF mit Tc-99m-ECD-SPECT (ECD) und die BRD mit 1-123-Jomazenil-SPECT (IMZ) untersucht. Alle drei Untersuchungen wurden interiktual und binnen vier Wochen bei jedem Patienten durchgeführt. Die Dauer der Epilepsie betrug zwischen 0,1 und 42 Jahre (Median 4,0 Jahre). Die SPECT-Studien wurden mit der Dreikopfkamera Multispect 3, die PET-Studien mit dem PET-System ECAT EXACT 47 durchgeführt. Mit Hilfe von Linienprofilen wurden rCMRGIc, rCBF und BRD in vier temporalen Regionen bestimmt; die daraus errechneten Asymmetrie-Indizes (ASY) wurden mit den 95%-Konfidenzin- tervallen von Kontrollpersonen verglichen. Ergebnisse: Von den 49 Patienten wiesen 35 (71%) einen signifikant pathologischen ASY in mindestens einer Region auf; der rCMRGIc war asymmetrisch bei 41 % der Patienten, die BRD bei 29%, und der rCBF bei 24%. Bei einem Patienten waren alle drei Variablen pathologisch, bei zwei der rCMRGIc und die BRD, bei drei der rCMRGIc und der rCBF und bei vier weiteren Patienten der rCBF und die BRD. Eine isolierte Asymmetrie des rCMRGIc fand sich in 14, der BRD in 7 und des rCBF in 4 Fällen. Es gab keine Diskrepanzen in der Latéralisation zwischen den drei Methoden. Schlußfolgerung: Die Mehrzahl der Patienten mit medikamentös- nichtrefraktären CPS weist eine Abnormalität des rCMRGIc, der BRD oder des rCBF auf. In diesem Patientenkollektiv zeigt FDG-PET am häufigsten eine temporale Auffälligkeit.

Summary

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 investigate the frequency of temporal asymmetries in regional cerebral glucose consumption (rCMRGIc), regional cerebral blood flow (rCBF), and regional cerebral benzodiazepine receptor density (BRD) in this group of patients. Methods: The study included 49 patients with medically non-refractory cryptogenic CPS (age: 36.0 ± 16.1 years). rCMRGIc was studied with F-18-FDG-PET (FDG), rCBF with Tc-99m-ECD-SPECT (ECD), and BRD with l-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 uptake of ECD and IMZ, were measured in four temporal regions of interest (ROIs), and asymmetry indices were calculated (ASY). The results were compared to 95% confidence intervals determined in control subjects. Results: Thirty-five of the 49 (71%) patients had at least one significantly elevated ASY; temporal rCMRGIc was asymmetrical in 41 % of the patients, temporal BRD in 29%, and temporal rCBF in 24%. One patient had an asymmetry of all three variables, two of temporal rCMRGIc and BRD, three of temporal rCMRGIc and rCBF, and another four of rCBF and BRD. Fourteen patients had an isolated temporal asymmetry in rCMRGIc, seven in BRD, and four in rCBF. A discrepancy in lateralization between the three modalities was not observed. Conclusion: The majority of patients 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.

Schlüsselwörter

Fokale Epilepsie - PET - SPECT - regionaler zerebraler Glukoseverbrauch - regionaler zerebraler Blutfluß - regionale zerebrale Benzodiazepin- Rezeptordichte

Keywords

Focal epilepsy - PET - SPECT - regional cerebral glucose consumption - regional cerebral blood flow - regional cerebral benzodiazepine receptor density

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