Deep gray matter maturation in very preterm neonates: regional variations and pathology-related age-dependent changes in magnetization transfer ratio

Radiology. 2012 May;263(2):510-7. doi: 10.1148/radiol.12110367. Epub 2012 Mar 13.

Abstract

Purpose: To elucidate the relationship between gestational age, pathologic findings, and magnetic resonance (MR) imaging measures of tissue maturation-myelination in deep gray matter areas in very preterm neonates imaged at birth.

Materials and methods: The study was approved by the research ethics board. Written informed consent was given by the infants' parents. Forty-two preterm neonates (19 boys; median gestational age, 28.7 weeks) with normal-appearing gray matter structures at presentation underwent MR imaging within 2 weeks of birth that included T1- and T2-weighted, magnetization transfer, and T1 relaxometry sequences. Neonates were separated into the following groups: those with normal findings (n = 23), those with white matter injury (WMI) (n = 9), those with grade I germinal matrix hemorrhage (GMH) (n = 3), and those with grade II GMH and WMI (n = 7). Analysis of covariance was used to determine regional effects of age and pathologic findings on magnetization transfer ratio (MTR) and to assess the relationship between MTR and T1.

Results: MTR increased linearly with age (P ≤ .0265), with a similar rate of change of 0.32% per week (95% confidence interval [CI]: 0.16, 0.49) in the basal ganglia (BG) and thalami. A lower trend (0.11% per week; 95% CI: -0.05, 0.28) was seen in the pons. Higher MTRs were seen in the thalami and pons than in the BG (P < .05), indicating earlier maturation. Accordingly, higher T1 values were observed in the BG relative to the thalami (P < .0001). Higher MTRs in the BG were observed in the group of neonates with normal findings at presentation than in the group with WMI (P = .02).

Conclusion: MTR measurements can be used to monitor early myelination in the developing brain and to help detect changes in tissue that are not shown on T1- and T2-weighted MR images.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Algorithms
  • Analysis of Variance
  • Basal Ganglia / growth & development
  • Brain / growth & development*
  • Female
  • Gestational Age
  • Humans
  • Image Interpretation, Computer-Assisted
  • Infant, Newborn
  • Infant, Premature*
  • Longitudinal Studies
  • Magnetic Resonance Imaging / methods*
  • Male
  • Nerve Fibers, Myelinated
  • Prospective Studies
  • Thalamus / growth & development