title: Longitudinal quantitative analysis of the tuber-to-brain proportion in patients with tuberous sclerosis.
abstract: OBJECTIVE
  In patients with tuberous sclerosis complex (TSC), the tuber-to-brain proportion (TBP) is a marker of seizure severity and cognitive function. However, few studies have quantified the TBP. Furthermore, authors of these studies have measured the TBP at only a single time point, despite the fact that tuber cells were found to express proliferation markers, suggesting that they may be dynamic lesions. Authors of the present study used a semi-automated tuber segmentation program to determine whether the TBP changes over time.
  
  
  METHODS
  Axial FLAIR MR images were retrospectively identified for patients with TSC who had undergone imaging at the authors' institution between February 1998 and June 2009. Using FireVoxel software, the TBP was measured for each patient at a minimum interval of 2 years.
  
  
  RESULTS
  Twelve patients meeting the study inclusion criteria were identified. The mean TBP was 1.88% (range 0.38%-3.70%). Eight patients demonstrated minimal changes and 3 patients demonstrated small increases in TBP. The remaining patient exhibited a decrease of 1.00%, which correlated with a visible decrease in the size of 2 cerebellar lesions.
  
  
  CONCLUSIONS
  Semi-automated brain segmentation is a valuable tool in the longitudinal study of tubers. A subset of patients with TSC, particularly those with cerebellar lesions, may exhibit changes in the TBP over time.
authors.affiliation: Department of Neurosurgery, University of Maryland Medical Center, Baltimore, Maryland, USA.
authors.forename: David S
authors.initials: DS
authors.lastname: Hersh
authors.forename: Jonathan
authors.initials: J
authors.lastname: Chun
authors.forename: Howard L
authors.initials: HL
authors.lastname: Weiner
authors.forename: Steven
authors.initials: S
authors.lastname: Pulitzer
authors.forename: Henry
authors.initials: H
authors.lastname: Rusinek
authors.forename: Jonathan
authors.initials: J
authors.lastname: Roth
authors.forename: Orrin
authors.initials: O
authors.lastname: Devinsky
authors.forename: Sarah S
authors.initials: SS
authors.lastname: Milla
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D001931:Brain Mapping / Q000379:methods; D015986:Confounding Factors, Epidemiologic; D004827:Epilepsy / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D018579:Patient Selection; D012189:Retrospective Studies; D018401:Sample Size; D012720:Severity of Illness Index; D014402:Tuberous Sclerosis / Q000150:complications* / Q000473:pathology* / Q000503:physiopathology