title: Lateralization of temporal lobe epilepsy (TLE) and discrimination of TLE from extra-TLE using pattern analysis of magnetic resonance spectroscopic and volumetric data.
abstract: OBJECTIVE
  To examine whether or not pattern analysis of magnetic resonance volumetric (MRVol) and proton magnetic resonance spectroscopic imaging (1H-MRSI) data would enable (a) the accurate lateralization of temporal lobe epilepsy (TLE) and (b) the discrimination of TLE from extratemporal epilepsy (E-TLE).
  
  
  METHODS
  For lateralization analysis, we used data from 150 nonforeign tissue lesional TLE patients [88 left-sided (L-TLE), 46 right-sided (R-TLE), and 16 bilateral (Bi-TLE)]. For the discrimination of TLE from E-TLE, we used data from 174 patients (145 with unilateral TLE, 14 with unilateral E-TLE, and 15 with widespread epileptogenic zones involving both the TL and extra-TL regions-multilobar epilepsy). A series of "leave-one-out" cross-validated linear discriminant analyses were performed using the MRVol and 1H-MRSI data sets to lateralize TLE and discriminate it from E-TLE.
  
  
  RESULTS
  Lateralization: The leave-one-out linear discriminant analyses were able to correctly lateralize (with a posterior probability >0.50) 120 (90%) of the 134 L-TLE and R-TLE patients. Imposing higher posterior probability (>0.95) increased accuracy of lateralization to 98%, with only two discordant cases who underwent surgery on the side of electroencephalogram, and both had bad outcome. Discrimination: the leave-one-out linear discriminant analyses were able to correctly classify (with a posterior probability >0.50) 142 (89%) of the 159 TLE and E-TLE patients. Accuracy increased slightly as higher posterior probability cutoffs were imposed, with fewer patients being classified.
  
  
  CONCLUSIONS
  Pattern analysis of 1H-MRSI and MRVol data can accurately lateralize TLE. Discriminating TLE from E-TLE was less accurate, probably due to the presence of temporal lobe damage in some patients with E-TLE reflecting dual pathology.
authors.affiliation: Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada.
authors.forename: L M
authors.initials: LM
authors.lastname: Li
authors.forename: Z
authors.initials: Z
authors.lastname: Caramanos
authors.forename: F
authors.initials: F
authors.lastname: Cendes
authors.forename: F
authors.initials: F
authors.lastname: Andermann
authors.forename: S B
authors.initials: SB
authors.lastname: Antel
authors.forename: F
authors.initials: F
authors.lastname: Dubeau
authors.forename: D L
authors.initials: DL
authors.lastname: Arnold
mesh_terms: D000679:Amygdala / Q000033:anatomy & histology; D003937:Diagnosis, Differential; D016002:Discriminant Analysis; D004569:Electroencephalography / Q000706:statistics & numerical data; D004827:Epilepsy / Q000175:diagnosis; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis*; D007839:Functional Laterality; D006624:Hippocampus / Q000033:anatomy & histology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000706:statistics & numerical data*; D009682:Magnetic Resonance Spectroscopy; D015999:Multivariate Analysis; D013702:Temporal Lobe / Q000033:anatomy & histology*