Tract shape modeling detects changes associated with preterm birth and neuroprotective treatment effects

Neuroimage Clin. 2015 Mar 28;8:51-8. doi: 10.1016/j.nicl.2015.03.021. eCollection 2015.

Abstract

Preterm birth is associated with altered connectivity of neural circuits. We developed a tract segmentation method that provides measures of tract shape and integrity (probabilistic neighborhood tractography, PNT) from diffusion MRI (dMRI) data to test the hypotheses: 1) preterm birth is associated with alterations in tract topology (R), and tract-averaged mean diffusivity (〈D〉) and fractional anisotropy (FA); 2) neural systems are separable based on tract-averaged dMRI parameters; and 3) PNT can detect neuroprotective treatment effects. dMRI data were collected from 87 preterm infants (mean gestational age 29(+1) weeks, range 23(+2) -34(+6)) at term equivalent age and 24 controls (mean gestational age 39(+6) weeks). PNT was used to segment eight major fasciculi, characterize topology, and extract tract-averaged〈D〉and FA. Tract topology was altered by preterm birth in all tracts except the splenium (p < 0.05, false discovery rate [FDR] corrected). After adjustment for age at scan, tract-averaged〈D〉was increased in the genu and splenium, right corticospinal tract (CST) and the left and right inferior longitudinal fasciculi (ILF) in preterm infants compared with controls (p < 0.05, FDR), while tract-averaged FA was decreased in the splenium and left ILF (p < 0.05, FDR). Specific fasciculi were separable based on tract-averaged〈D〉and FA values. There was a modest decrease in tract-averaged〈D〉in the splenium of preterm infants who had been exposed to antenatal MgSO4 for neuroprotection (p = 0.002). Tract topology is a biomarker of preterm brain injury. The data provide proof of concept that tract-averaged dMRI parameters have utility for evaluating tissue effects of perinatal neuroprotective strategies.

Keywords: Brain; Infant; Magnesium sulfate; Magnetic resonance image; Neuroprotection; Preterm.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomarkers
  • Brain Injuries / drug therapy
  • Brain Injuries / pathology*
  • Diffusion Magnetic Resonance Imaging / methods*
  • Female
  • Gestational Age
  • Humans
  • Infant, Newborn
  • Infant, Premature*
  • Magnesium Sulfate / therapeutic use
  • Male
  • Neural Pathways / drug effects
  • Neural Pathways / pathology
  • Neuroprotective Agents / therapeutic use
  • White Matter / drug effects
  • White Matter / pathology*

Substances

  • Biomarkers
  • Neuroprotective Agents
  • Magnesium Sulfate