title: Early Postnatal Myelin Content Estimate of White Matter via T1w/T2w Ratio.
abstract: OBJECTIVE
  To develop and evaluate a novel processing framework for the relative quantification of myelin content in cerebral white matter (WM) regions from brain MRI data via a computed ratio of T1 to T2 weighted intensity values.
  
  
  METHODS
  We employed high resolution (1mm3isotropic) T1 and T2 weighted MRI from 46 (28 male, 18 female) neonate subjects (typically developing controls) scanned on a Siemens Tim Trio 3T at UC Irvine.
  
  
  METHODS
  We developed a novel, yet relatively straightforward image processing framework for WM myelin content estimation based on earlier work by Glasser et al. We first co-register the structural MRI data to correct for motion. Then, background areas are masked out via a joint T1w and T2 foreground mask computed. Raw T1w/T2w-ratios images are computed next. For purpose of calibration across subjects, we first coarsely segment the fat-rich facial regions via an atlas co-registration. Linear intensity rescaling based on median T1w/T2w-ratio values in those facial regions yields calibrated T1w/T2w-ratio images. Mean values in lobar regions are evaluated using standard statistical analysis to investigate their interaction with age at scan.
  
  
  RESULTS
  Several lobes have strongly positive significant interactions of age at scan with the computed T1w/T2w-ratio. Most regions do not show sex effects. A few regions show no measurable effects of change in myelin content change within the first few weeks of postnatal development, such as cingulate and CC areas, which we attribute to sample size and measurement variability.
  
  
  CONCLUSIONS
  We developed and evaluated a novel way to estimate white matter myelin content for use in studies of brain white matter development.
authors.affiliation: Department of Psychiatry, University of North Carolina, Chapel Hill.
authors.forename: Kevin
authors.initials: K
authors.lastname: Lee
authors.affiliation: Department of Psychiatry, University of North Carolina, Chapel Hill.
authors.forename: Marie
authors.initials: M
authors.lastname: Cherel
authors.affiliation: Department of Psychiatry, University of North Carolina, Chapel Hill.
authors.forename: Francois
authors.initials: F
authors.lastname: Budin
authors.affiliation: Department of Psychiatry, University of North Carolina, Chapel Hill.
authors.forename: John
authors.initials: J
authors.lastname: Gilmore
authors.affiliation: Department of Psychiatry, University of North Carolina, Chapel Hill.
authors.forename: Kirsten Zaldarriaga
authors.initials: KZ
authors.lastname: Consing
authors.affiliation: Department of Pediatrics, University of California, Irvine.
authors.forename: Jerod
authors.initials: J
authors.lastname: Rasmussen
authors.affiliation: Department of Pediatrics, University of California, Irvine.
authors.forename: Pathik D
authors.initials: PD
authors.lastname: Wadhwa
authors.affiliation: Department of Pediatrics, University of California, Irvine ; Institute for Medical Psychology, Charité University Medicine, Berlin, Germany.
authors.forename: Sonja
authors.initials: S
authors.lastname: Entringer
authors.affiliation: Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis.
authors.forename: Matthew F
authors.initials: MF
authors.lastname: Glasser
authors.affiliation: Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis.
authors.forename: David C
authors.initials: DC
authors.lastname: Van Essen
authors.affiliation: Department of Pediatrics, University of California, Irvine ; Institute for Medical Psychology, Charité University Medicine, Berlin, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Buss
authors.affiliation: Department of Psychiatry, University of North Carolina, Chapel Hill ; Department of Computer Science, University of North Carolina, Chapel Hill.
authors.forename: Martin
authors.initials: M
authors.lastname: Styner
keywords: Image Processing; Magnetic Resonance Imaging; Myelin Content; White matter