Diffusion tensor imaging colour mapping threshold for identification of ventilation-induced brain injury after intrauterine inflammation in preterm lambs

Dhafer M. Alahmari, Beatrice Skiold, Samantha K. Barton, Ilias Nitsos, Courtney McDonald, Suzanne L. Miller, Valerie Zahra, Robert Galinsky, Qi-Zhu Wu, Michael John Farrell, Timothy J. Moss, Stuart B. Hooper, James T. Pearson, Graeme R. Polglase

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Purpose: The aim of this study is to examine whether advanced magnetic resonance imaging (MRI) techniques can detect early brain injury caused by intrauterine inflammation and inappropriate initial respiratory support in preterm lambs.

Hypothesis: Neuropathology caused by intrauterine inflammation is exacerbated by mechanical ventilation at birth and is detectable with advanced MRI techniques.

Methods: Pregnant ewes received intra-amniotic lipopolysaccharide (LPS) 7 days prior to delivery at ~125 days of gestation (85% of gestation), whereupon lambs were delivered and randomised to receive an injurious (LPS + INJ, n = 6) or protective (LPS + PROT, n = 6) ventilation strategy. MRI of the brain was conducted 90 min after preterm delivery, using structural, diffusion tensor imaging (DTI), and magnetic resonance spectroscopy (MRS) techniques. A colour map threshold technique was utilised to compare distributions of low diffusivity voxels in the brains of LPS-exposed lambs with those not exposed to LPS (PROT, n = 7 PROT and INJ, n = 10).

Results: No overt cerebral injury was identified on structural MRI images of any lamb. However, on DTI, axial diffusivity, radial diffusivity, and mean diffusivity values were lower and significantly more heterogeneous in specific brain regions of lambs in the LPS + INJ group compared to the LPS + PROT group. Colour mapping revealed lower diffusivity in the thalamus, periventricular white matter, internal capsule, and frontal white matter in the LPS + INJ group compared to LPS + PROT group. The MRS peak area ratios of lactate, relative to those for the metabolites creatine, choline, and N-acetylaspartate, were not different between LPS-exposed groups. Lambs exposed to LPS had lower diffusivity within the white matter regions assessed than non-LPS-treated control lambs.

Conclusion: DTI colour map threshold techniques detected early brain injury in preterm lambs exposed to intrauterine inflammation and detected differences between injurious and protective ventilation strategies. DTI mapping approaches are potentially useful for early detection of subtle brain injury in premature infants.
Original languageEnglish
Article number70
JournalFrontiers in Pediatrics
Volume5
DOIs
Publication statusPublished - 5 Apr 2017

Keywords

  • Brain
  • Delivery room
  • Diffusion tensor imaging
  • Magnetic resonance imaging
  • Neonate

Cite this

@article{bb4a7fa0916b4d9698893d178c1e8ce2,
title = "Diffusion tensor imaging colour mapping threshold for identification of ventilation-induced brain injury after intrauterine inflammation in preterm lambs",
abstract = "Purpose: The aim of this study is to examine whether advanced magnetic resonance imaging (MRI) techniques can detect early brain injury caused by intrauterine inflammation and inappropriate initial respiratory support in preterm lambs.Hypothesis: Neuropathology caused by intrauterine inflammation is exacerbated by mechanical ventilation at birth and is detectable with advanced MRI techniques.Methods: Pregnant ewes received intra-amniotic lipopolysaccharide (LPS) 7 days prior to delivery at ~125 days of gestation (85{\%} of gestation), whereupon lambs were delivered and randomised to receive an injurious (LPS + INJ, n = 6) or protective (LPS + PROT, n = 6) ventilation strategy. MRI of the brain was conducted 90 min after preterm delivery, using structural, diffusion tensor imaging (DTI), and magnetic resonance spectroscopy (MRS) techniques. A colour map threshold technique was utilised to compare distributions of low diffusivity voxels in the brains of LPS-exposed lambs with those not exposed to LPS (PROT, n = 7 PROT and INJ, n = 10).Results: No overt cerebral injury was identified on structural MRI images of any lamb. However, on DTI, axial diffusivity, radial diffusivity, and mean diffusivity values were lower and significantly more heterogeneous in specific brain regions of lambs in the LPS + INJ group compared to the LPS + PROT group. Colour mapping revealed lower diffusivity in the thalamus, periventricular white matter, internal capsule, and frontal white matter in the LPS + INJ group compared to LPS + PROT group. The MRS peak area ratios of lactate, relative to those for the metabolites creatine, choline, and N-acetylaspartate, were not different between LPS-exposed groups. Lambs exposed to LPS had lower diffusivity within the white matter regions assessed than non-LPS-treated control lambs.Conclusion: DTI colour map threshold techniques detected early brain injury in preterm lambs exposed to intrauterine inflammation and detected differences between injurious and protective ventilation strategies. DTI mapping approaches are potentially useful for early detection of subtle brain injury in premature infants.",
keywords = "Brain, Delivery room, Diffusion tensor imaging, Magnetic resonance imaging, Neonate",
author = "Alahmari, {Dhafer M.} and Beatrice Skiold and Barton, {Samantha K.} and Ilias Nitsos and Courtney McDonald and Miller, {Suzanne L.} and Valerie Zahra and Robert Galinsky and Qi-Zhu Wu and Farrell, {Michael John} and Moss, {Timothy J.} and Hooper, {Stuart B.} and Pearson, {James T.} and Polglase, {Graeme R.}",
year = "2017",
month = "4",
day = "5",
doi = "10.3389/fped.2017.00070",
language = "English",
volume = "5",
journal = "Frontiers in Pediatrics",
issn = "2296-2360",
publisher = "Frontiers Media",

}

TY - JOUR

T1 - Diffusion tensor imaging colour mapping threshold for identification of ventilation-induced brain injury after intrauterine inflammation in preterm lambs

AU - Alahmari, Dhafer M.

AU - Skiold, Beatrice

AU - Barton, Samantha K.

AU - Nitsos, Ilias

AU - McDonald, Courtney

AU - Miller, Suzanne L.

AU - Zahra, Valerie

AU - Galinsky, Robert

AU - Wu, Qi-Zhu

AU - Farrell, Michael John

AU - Moss, Timothy J.

AU - Hooper, Stuart B.

AU - Pearson, James T.

AU - Polglase, Graeme R.

PY - 2017/4/5

Y1 - 2017/4/5

N2 - Purpose: The aim of this study is to examine whether advanced magnetic resonance imaging (MRI) techniques can detect early brain injury caused by intrauterine inflammation and inappropriate initial respiratory support in preterm lambs.Hypothesis: Neuropathology caused by intrauterine inflammation is exacerbated by mechanical ventilation at birth and is detectable with advanced MRI techniques.Methods: Pregnant ewes received intra-amniotic lipopolysaccharide (LPS) 7 days prior to delivery at ~125 days of gestation (85% of gestation), whereupon lambs were delivered and randomised to receive an injurious (LPS + INJ, n = 6) or protective (LPS + PROT, n = 6) ventilation strategy. MRI of the brain was conducted 90 min after preterm delivery, using structural, diffusion tensor imaging (DTI), and magnetic resonance spectroscopy (MRS) techniques. A colour map threshold technique was utilised to compare distributions of low diffusivity voxels in the brains of LPS-exposed lambs with those not exposed to LPS (PROT, n = 7 PROT and INJ, n = 10).Results: No overt cerebral injury was identified on structural MRI images of any lamb. However, on DTI, axial diffusivity, radial diffusivity, and mean diffusivity values were lower and significantly more heterogeneous in specific brain regions of lambs in the LPS + INJ group compared to the LPS + PROT group. Colour mapping revealed lower diffusivity in the thalamus, periventricular white matter, internal capsule, and frontal white matter in the LPS + INJ group compared to LPS + PROT group. The MRS peak area ratios of lactate, relative to those for the metabolites creatine, choline, and N-acetylaspartate, were not different between LPS-exposed groups. Lambs exposed to LPS had lower diffusivity within the white matter regions assessed than non-LPS-treated control lambs.Conclusion: DTI colour map threshold techniques detected early brain injury in preterm lambs exposed to intrauterine inflammation and detected differences between injurious and protective ventilation strategies. DTI mapping approaches are potentially useful for early detection of subtle brain injury in premature infants.

AB - Purpose: The aim of this study is to examine whether advanced magnetic resonance imaging (MRI) techniques can detect early brain injury caused by intrauterine inflammation and inappropriate initial respiratory support in preterm lambs.Hypothesis: Neuropathology caused by intrauterine inflammation is exacerbated by mechanical ventilation at birth and is detectable with advanced MRI techniques.Methods: Pregnant ewes received intra-amniotic lipopolysaccharide (LPS) 7 days prior to delivery at ~125 days of gestation (85% of gestation), whereupon lambs were delivered and randomised to receive an injurious (LPS + INJ, n = 6) or protective (LPS + PROT, n = 6) ventilation strategy. MRI of the brain was conducted 90 min after preterm delivery, using structural, diffusion tensor imaging (DTI), and magnetic resonance spectroscopy (MRS) techniques. A colour map threshold technique was utilised to compare distributions of low diffusivity voxels in the brains of LPS-exposed lambs with those not exposed to LPS (PROT, n = 7 PROT and INJ, n = 10).Results: No overt cerebral injury was identified on structural MRI images of any lamb. However, on DTI, axial diffusivity, radial diffusivity, and mean diffusivity values were lower and significantly more heterogeneous in specific brain regions of lambs in the LPS + INJ group compared to the LPS + PROT group. Colour mapping revealed lower diffusivity in the thalamus, periventricular white matter, internal capsule, and frontal white matter in the LPS + INJ group compared to LPS + PROT group. The MRS peak area ratios of lactate, relative to those for the metabolites creatine, choline, and N-acetylaspartate, were not different between LPS-exposed groups. Lambs exposed to LPS had lower diffusivity within the white matter regions assessed than non-LPS-treated control lambs.Conclusion: DTI colour map threshold techniques detected early brain injury in preterm lambs exposed to intrauterine inflammation and detected differences between injurious and protective ventilation strategies. DTI mapping approaches are potentially useful for early detection of subtle brain injury in premature infants.

KW - Brain

KW - Delivery room

KW - Diffusion tensor imaging

KW - Magnetic resonance imaging

KW - Neonate

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U2 - 10.3389/fped.2017.00070

DO - 10.3389/fped.2017.00070

M3 - Article

VL - 5

JO - Frontiers in Pediatrics

JF - Frontiers in Pediatrics

SN - 2296-2360

M1 - 70

ER -