title: Volumetric brain analysis in neurosurgery: Part 3. Volumetric CT analysis as a predictor of seizure outcome following temporal lobectomy.
abstract: OBJECTIVE
  The incidence of temporal lobe epilepsy (TLE) due to mesial temporal sclerosis (MTS) can be high in developing countries. Current diagnosis of MTS relies on structural MRI, which is generally unavailable in developing world settings. Given widespread effects on temporal lobe structure beyond hippocampal atrophy in TLE, the authors propose that CT volumetric analysis can be used in patient selection to help predict outcomes following resection.
  
  
  METHODS
  Ten pediatric patients received preoperative CT scans and temporal resections at the CURE Children's Hospital of Uganda. Engel classification of seizure control was determined 12 months postoperatively. Temporal lobe volumes were measured from CT and from normative MR images using the Cavalieri method. Whole brain and fluid volumes were measured using particle filter segmentation. Linear discrimination analysis (LDA) was used to classify seizure outcome by temporal lobe volumes and normalized brain volume.
  
  
  RESULTS
  Epilepsy patients showed normal to small brain volumes and small temporal lobes bilaterally. A multivariate measure of the volume of each temporal lobe separated patients who were seizure free (Engel Class IA) from those with incomplete seizure control (Engel Class IB/IIB) with LDA (p<0.01). Temporal lobe volumes also separate normal subjects, patients with Engel Class IA outcomes, and patients with Class IB/IIB outcomes (p<0.01). Additionally, the authors demonstrated that age-normalized whole brain volume, in combination with temporal lobe volumes, may further improve outcome prediction (p<0.01).
  
  
  CONCLUSIONS
  This study shows strong evidence that temporal lobe and brain volume can be predictive of seizure outcome following temporal lobe resection, and that volumetric CT analysis of the temporal lobe may be feasible in lieu of structural MRI when the latter is unavailable. Furthermore, since the authors' methods are modality independent, these findings suggest that temporal lobe and normative brain volumes may further be useful in the selection of patients for temporal lobe resection when structural MRI is available.
authors.affiliation: Center for Neural Engineering.
authors.forename: Jason G
authors.initials: JG
authors.lastname: Mandell
authors.forename: Kenneth L
authors.initials: KL
authors.lastname: Hill
authors.forename: Dan T D
authors.initials: DT
authors.lastname: Nguyen
authors.forename: Kevin W
authors.initials: KW
authors.lastname: Moser
authors.forename: Robert E
authors.initials: RE
authors.lastname: Harbaugh
authors.forename: James
authors.initials: J
authors.lastname: McInerney
authors.forename: Brian Kaaya
authors.initials: BK
authors.lastname: Nsubuga
authors.forename: John K
authors.initials: JK
authors.lastname: Mugamba
authors.forename: Derek
authors.initials: D
authors.lastname: Johnson
authors.forename: Benjamin C
authors.initials: BC
authors.lastname: Warf
authors.forename: Warren
authors.initials: W
authors.lastname: Boling
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Webb
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Schiff
mesh_terms: D000293:Adolescent; D038481:Anterior Temporal Lobectomy; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology*; D002555:Cerebrospinal Fluid; D002648:Child; D002675:Child, Preschool; D003071:Cognition; D054893:Cone-Beam Computed Tomography; D004833:Epilepsy, Temporal Lobe / Q000601:surgery*; D005260:Female; D005625:Frontal Lobe / Q000473:pathology; D006801:Humans; D006849:Hydrocephalus / Q000473:pathology* / Q000523:psychology* / Q000601:surgery; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D019635:Neurosurgical Procedures / Q000379:methods; D009778:Occipital Lobe / Q000473:pathology; D009929:Organ Size; D011237:Predictive Value of Tests; D012640:Seizures / Q000209:etiology; D016896:Treatment Outcome; D014454:Uganda
keywords: CAH = cortico-amygdalo-hippocampectomy; CCHU = CURE Children's Hospital of Uganda; CT; EEG = encephalography; IRB = institutional review board; LDA = linear discrimination analysis; MMSE = Mini–Mental State Examination; MRI; MTS = mesial temporal sclerosis; TLE = temporal lobe epilepsy; developing country; epilepsy; technique; temporal lobe; volume