title: Structural development of human brain white matter from mid-fetal to perinatal stage.
abstract: The structures of developing human brain white matter (WM) tracts can be effectively quantified by DTI-derived metrics, including fractional anisotropy (FA), mean, axial and radial diffusivity (MD, AD and RD). However, dynamics of WM microstructure during very early developmental period from mid-fetal to perinatal stage is unknown. It is difficult to accurately measure microstructural properties of these WM tracts due to severe contamination from cerebrospinal fluid (CSF). In this study, high resolution DTI of fetal brains at mid-fetal stage (20 weeks of gestation or 20wg), 19 brains in the middle of 3rdtrimester (35wg) and 17 brains around term (40wg) were acquired. We established first population-averaged DTI templates at these three time points and extracted WM skeleton. 16 major WM tracts in limbic, projection, commissural and association tract groups were traced with DTI tractography in native space. The WM skeleton in the template space was inversely transformed back to the native space for measuring core WM microstructures of each individual tract. Continuous microstructural enhancement and volumetric increase of WM tracts were found from 20wg to 40wg. The microstructural enhancement from FA measurement is decelerated in late 3rdtrimester compared to mid-fetal to middle 3rdtrimester, while volumetric increase of prefrontal WM tracts is accelerated. The microstructural enhancement from 35wg to 40wg is heterogeneous among different tract groups with microstructures of association tracts undergoing most dramatic change. Besides decreases of RD indicating active myelination, the decrease of AD for most WM tracts during late 3rdtrimester suggests axonal packing process.
authors.affiliation: Advanced Imaging Research Center, University of Texas Southwestern Medical Center, 5323 HarryHines Blvd, Dallas, TX, USA 75390.
authors.forename: Austin
authors.initials: A
authors.lastname: Ouyang
authors.affiliation: Advanced Imaging Research Center, University of Texas Southwestern Medical Center, 5323 HarryHines Blvd, Dallas, TX, USA 75390; Research Center for Sectional and Imaging Anatomy, Shandong University, No 44 West Wenhua Road, Jinan, Shandong, China 250012.
authors.forename: Qiaowen
authors.initials: Q
authors.lastname: Yu
authors.affiliation: Advanced Imaging Research Center, University of Texas Southwestern Medical Center, 5323 HarryHines Blvd, Dallas, TX, USA 75390.
authors.forename: Virendra
authors.initials: V
authors.lastname: Mishra
authors.affiliation: Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 HarryHines Blvd, Dallas, TX, USA 75390.
authors.forename: Lina
authors.initials: L
authors.lastname: Chalak
authors.affiliation: Advanced Imaging Research Center, University of Texas Southwestern Medical Center, 5323 HarryHines Blvd, Dallas, TX, USA 75390.
authors.forename: Tina
authors.initials: T
authors.lastname: Jeon
authors.affiliation: Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 HarryHines Blvd, Dallas, TX, USA 75390.
authors.forename: Muraleedharan
authors.initials: M
authors.lastname: Sivarajan
authors.affiliation: Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 HarryHines Blvd, Dallas, TX, USA 75390.
authors.forename: Greg
authors.initials: G
authors.lastname: Jackson
authors.affiliation: Department of Radiology, University of Texas Southwestern Medical Center, 5323 HarryHines Blvd, Dallas, TX, USA 75390.
authors.forename: Nancy
authors.initials: N
authors.lastname: Rollins
authors.affiliation: Research Center for Sectional and Imaging Anatomy, Shandong University, No 44 West Wenhua Road, Jinan, Shandong, China 250012.
authors.forename: Shuwei
authors.initials: S
authors.lastname: Liu
authors.affiliation: Advanced Imaging Research Center, University of Texas Southwestern Medical Center, 5323 HarryHines Blvd, Dallas, TX, USA 75390; Department of Radiology, University of Texas Southwestern Medical Center, 5323 HarryHines Blvd, Dallas, TX, USA 75390.
authors.forename: Hao
authors.initials: H
authors.lastname: Huang
keywords: DTI; development; fetal; microstructure; skeleton; template; tract; white matter