title: Involvement of the basal ganglia in refractory epilepsy: an 18F-fluoro-L-DOPA PET study using 2 methods of analysis.
abstract: Studies in animal models and epileptic patients have led to the suggestion that the basal ganglia (BG) are involved in seizures. PET with 6-18F-L-3,4-fluorodihydroxyphenylalanine (18F-fluoro-L-DOPA) has recently demonstrated a reduction of striatal dopamine uptake in drug-resistant epileptic patients with ring chromosome 20 (r20) using a multiple-time graphical analysis. The aim of the present study was to evaluate the involvement of dopamine in other epileptic syndromes using a multiple-time graphical analysis and the all-brain statistical parametric mapping (SPM) analysis.
  
  
  METHODS
  Patients with drug-resistant epilepsy were divided into 3 groups: group 1, with r20 epilepsy (n = 16; mean age +/- SD, 21.5 +/- 5.4 y); group 2, with resistant generalized "absence-like" epilepsy (n = 10; mean age, 32.3 +/- 11.4 y); and group 3, with drug-resistant temporal lobe epilepsy with hippocampal sclerosis (n = 9; mean age, 35.2 +/- 10.3 y). We compared 2 strategies of analysis of the 18F-fluoro-L-DOPA uptake constant (K(i), min(-1)) in BG using a multiple-time graphical analysis using regions of interest (the gold-standard method) and an SPM analysis using a voxel-by-voxel statistical t test to avoid a priori hypotheses in the analysis. Each epileptic group was compared with a group of healthy volunteers (n = 10; mean age, 45.1 +/- 16.5 y).
  
  
  RESULTS
  A decrease of the mean K(i) value was observed in the striatum in all groups of patients with both types of analysis. With multiple-time graphical analysis, the reduction was evident using the averaged K(i) values over both hemispheres in each BG. Unilateral decreases in each BG were detected in SPM analysis. A ratio of decrease of 18F-fluoro-L-DOPA uptake was observed in the 3 groups of patients. Only the SPM analysis showed a decrease of 18F-fluoro-L-DOPA uptake ipsilateral to the seizure side in patients with temporal lobe epilepsy. Moreover, the all-brain SPM analysis showed a decrease of 18F-fluoro-L-DOPA uptake in the substantia nigra bilaterally (P < 0.001).
  
  
  CONCLUSIONS
  This result confirms the involvement of dopamine neurotransmission in seizure control related to the type of epileptic syndrome. The difference in epileptic types may depend in part on the seizure frequency.
authors.affiliation: Commissariat à l'Energie Atomique, Direction des Sciences du Vivant, Département de Recherche Médicale, Service Hospitalier Frédéric Joliot, Orsay, France.
authors.forename: Viviane
authors.initials: V
authors.lastname: Bouilleret
authors.forename: Franck
authors.initials: F
authors.lastname: Semah
authors.forename: Arnaud
authors.initials: A
authors.lastname: Biraben
authors.forename: Delphine
authors.initials: D
authors.lastname: Taussig
authors.forename: Francine
authors.initials: F
authors.lastname: Chassoux
authors.forename: André
authors.initials: A
authors.lastname: Syrota
authors.forename: Maria-João
authors.initials: MJ
authors.lastname: Ribeiro
mesh_terms: D000328:Adult; D000465:Algorithms; D000927:Anticonvulsants / Q000627:therapeutic use; D001479:Basal Ganglia / Q000000981:diagnostic imaging*; D001931:Brain Mapping / Q000379:methods*; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives*; D004351:Drug Resistance; D004827:Epilepsy / Q000000981:diagnostic imaging* / Q000188:drug therapy; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D000927:Anticonvulsants; D019275:Radiopharmaceuticals; C043437:fluorodopa F 18; D004295:Dihydroxyphenylalanine