Preterm brain injury on term-equivalent age MRI in relation to perinatal factors and neurodevelopmental outcome at two years

Abstract

Objectives: First, to apply a recently extended scoring system for preterm brain injury at term-equivalent age (TEA-)MRI in a regional extremely preterm cohort; second, to identify independent perinatal factors associated with this score; and third, to assess the prognostic value of this TEA-MRI score with respect to early neurodevelopmental outcome.

Study design: 239 extremely preterm infants (median gestational age [range] in weeks: 26.6 [24.3-27.9]), admitted to the Wilhelmina Children's Hospital between 2006 and 2012 were included. Brain abnormalities in white matter, cortical and deep grey matter and cerebellum and brain growth were scored on T1- and T2-weighted TEA-MRI using the Kidokoro scoring system. Neurodevelopmental outcome was assessed at two years corrected age using the Bayley Scales of Infant and Toddler Development, third edition. The association between TEA-MRI and perinatal factors as well as neurodevelopmental outcome was evaluated using multivariable regression analysis.

Results: The distribution of brain abnormalities and brain metrics in the Utrecht cohort differed from the original St. Louis cohort (p < .05). Mechanical ventilation >7 days (β [95% confidence interval, CI]: 1.3 [.5; 2.0]) and parenteral nutrition >21 days (2.2 [1.2; 3.2]) were independently associated with higher global brain abnormality scores (p < .001). Global brain abnormality scores were inversely associated with cognitive (β in composite scores [95% CI]: -.7 [-1.2; -.2], p = .004), fine motor (β in scaled scores [95% CI]: -.1 [-.3; -.0], p = .007) and gross motor outcome (β in scaled scores [95% CI]: -.2 [-.3; -.1], p < .001) at two years corrected age, although the explained variances were low (R2 ≤.219).

Conclusion: Patterns of brain injury differed between cohorts. Prolonged mechanical ventilation and parenteral nutrition were identified as independent perinatal risk factors. The prognostic value of the TEA-MRI score was rather limited in this well-performing cohort.

Fig 1. Distribution of the global brain abnormality score and regional subscores across the Utrecht (n = 239) and St. Louis (n = 97) cohorts.

A left-sided shift of the curve can be appreciated for the Utrecht data.

Fig 2. Association between brain metrics on TEA-MRI and neurodevelopmental outcome in the Utrecht cohort (n = 239).

Presented are the residuals for cognitive outcome (i.e. corrected for maternal education, non-Western ethnicity, female sex, and test age), fine motor outcome (i.e. corrected for maternal education, GA, birth weight z-score, and test age), and gross motor outcome (i.e. corrected for maternal education, female sex, and birth weight z-score).