title: Magnetic resonance spectroscopy markers of axons and astrogliosis in relation to specific features of white matter injury in preterm infants.
abstract: BACKGROUND
  Punctate white matter lesions (pWMLs) and diffuse excessive high signal intensity (DEHSI) are commonly observed signal abnormalities on MRI scans of high-risk preterm infants near term-equivalent age. To establish whether these features are indicative abnormalities in axonal development or astroglia, we compared pWMLs and DEHSI to markers of axons and astrogliosis, derived from magnetic resonance spectroscopy (MRS).
  
  
  METHODS
  Data from 108 preterm infants (gestational age at birth 31.0 weeks ± 4.3; age at scan 41.2 weeks ± 6.0) who underwent MR examinations under clinical indications were included in this study. Linear regression analyses were used to test the effects of pWMLs and DEHSI on N-acetyl-aspartate (NAA) and myoinositol concentrations, respectively.
  
  
  RESULTS
  Across the full sample, pWMLs were associated with a reduction in NAA whereas moderate to severe DEHSI altered the normal age-dependent changes in myoinositol such that myoinositol levels were lower at younger ages with no change during the perinatal period. Subgroup analyses indicated that the above associations were driven by the subgroup of neonates with both pWMLs and moderate to severe DEHSI.
  
  
  CONCLUSIONS
  Overall, these findings suggest that pWMLs in conjunction with moderate/severe DEHSI may signify a population of infants at risk for long-term adverse neurodevelopmental outcome due to white matter injury and associated axonopathy. The loss of normal age-associated changes in myoinositol further suggests disrupted astroglial function and/or osmotic dysregulation.
authors.affiliation: Department of Radiology, Children's Hospital Los Angeles, Los Angeles, CA, USA.
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Wisnowski
authors.forename: Vincent J
authors.initials: VJ
authors.lastname: Schmithorst
authors.forename: Tena
authors.initials: T
authors.lastname: Rosser
authors.forename: Lisa
authors.initials: L
authors.lastname: Paquette
authors.forename: Marvin D
authors.initials: MD
authors.lastname: Nelson
authors.forename: Robin L
authors.initials: RL
authors.lastname: Haynes
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Painter
authors.forename: Stefan
authors.initials: S
authors.lastname: Blüml
authors.forename: Ashok
authors.initials: A
authors.lastname: Panigrahy
mesh_terms: D001369:Axons; D005911:Gliosis / Q000150:complications / Q000175:diagnosis*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000175:diagnosis*; D056784:Leukoencephalopathies / Q000150:complications / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy