title: Automated algorithm to measure changes in medial temporal lobe volume in Alzheimer disease.
abstract: BACKGROUND
  The change in volume of anatomic structures is as a sensitive indicator of Alzheimer disease (AD) progression. Although several methods are available to measure brain volumes, improvements in speed and automation are required. Our objective was to develop a fully automated, fast, and reliable approach to measure change in medial temporal lobe (MTL) volume, including primarily hippocampus.
  
  
  METHODS
  The MTL volume defined in an atlas image was propagated onto each baseline image and a level set algorithm was applied to refine the shape and smooth the boundary. The MTL of the baseline image was then mapped onto the corresponding follow-up image to measure volume change (ΔMTL). Baseline and 24 months 3D T1-weighted images from the Alzheimer Disease Neuroimaging Initiative (ADNI) were randomly selected for 50 normal elderly controls (NECs), 50 subjects with mild cognitive impairment (MCI) and 50 subjects with AD to test the algorithm. The method was compared to the FreeSurfer segmentation tools.
  
  
  RESULTS
  The average ΔMTL (mean±SEM) was 68±35mm(3) in NEC, 187±38mm(3) in MCI and 300±34mm(3) in the AD group and was significantly different (p<0.0001) between all three groups. The ΔMTL was correlated with cognitive decline.
  
  
  CONCLUSIONS
  Results for the FreeSurfer software were similar but did not detect significant differences between the MCI and AD groups.
  
  
  CONCLUSIONS
  This novel segmentation approach is fully automated and provides a robust marker of brain atrophy that shows different rates of atrophy over 2 years between NEC, MCI, and AD groups.
authors: Robarts Research Institute, University of Western Ontario, 1151 Richmond Street, London, Ontario, Canada N6A 3K7; Department of Medical Biophysics, University of Western Ontario, 1151 Richmond Street, London, Ontario, Canada N6A 3K7.
authors: Samaneh
authors: S
authors: Kazemifar
authors: Robarts Research Institute, University of Western Ontario, 1151 Richmond Street, London, Ontario, Canada N6A 3K7.
authors: John J
authors: JJ
authors: Drozd
authors: Department of Anatomy and Cell Biology, University of Western Ontario, 1151 Richmond Street, London, Ontario, Canada N6A 3K7.
authors: Nagalingam
authors: N
authors: Rajakumar
authors: Department of Medicine, University of Western Ontario, 1151 Richmond Street, London, Ontario, Canada N6A 3K7; Division of Aging, Rehabilitation and Geriatric Care, Lawson Health Research Institute, 268 Grosvenor Street, London, Ontario, Canada N6A 4V2.
authors: Michael J
authors: MJ
authors: Borrie
authors: Robarts Research Institute, University of Western Ontario, 1151 Richmond Street, London, Ontario, Canada N6A 3K7; Department of Medical Biophysics, University of Western Ontario, 1151 Richmond Street, London, Ontario, Canada N6A 3K7. Electronic address: rbartha@robarts.ca.
authors: Robert
authors: R
authors: Bartha
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000544:Alzheimer Disease / Q000473:pathology*; D060825:Cognitive Dysfunction / Q000473:pathology; D005260:Female; D006624:Hippocampus / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D013223:Statistics as Topic; D013702:Temporal Lobe / Q000473:pathology*
keywords: Alzheimer disease; Hippocampus; MRI; Medial temporal lobe segmentation; Multi-atlas; Shape