Brain MRI Measurements at a Term-Equivalent Age and Their Relationship to Neurodevelopmental Outcomes

BACKGROUND AND PURPOSE:An increased prevalence of disabilities is being observed as more preterm infants survive. This study was conducted to evaluate correlations between brain MR imaging measurements taken at a term-equivalent age and neurodevelopmental outcome at 2 years'' corrected age among very low–birth-weight infants.MATERIALS AND METHODS:Of the various brain MR imaging measurements obtained at term-equivalent ages, reproducible measurements of the transcerebellar diameter and anteroposterior length of the corpus callosum on sagittal images were compared with neurodevelopmental outcomes evaluated by the Bayley Scales of Infant Development (II) at 2 years'' corrected age (mean ± standard deviation, 16.1 ± 6.4 months of age).RESULTS:Ninety infants were enrolled. The mean gestational age at birth was 27 weeks and the mean birth weight was 805.5 g. A short corpus callosal length was associated with a Mental Developmental Index <70 (P = .047) and high-risk or diagnosed cerebral palsy (P = .049). A small transcerebellar diameter was associated with a Psychomotor Developmental Index <70 (P = .003), Mental Developmental Index <70 (P = .004), and major neurologic disability (P = .006).CONCLUSIONS:A small transcerebellar diameter and short corpus callosal length on brain MR imaging at a term-equivalent age are related to adverse neurodevelopmental outcomes at a corrected age of 2 years and could be a useful adjunctive tool for counseling parents about future developmental outcomes.

The survival rate of preterm infants has increased with the advances in neonatal care in recent decades. However, a higher prevalence of disabilities has also been observed in survivors of preterm birth at infancy and in childhood.^1,2 Factors such as intraventricular hemorrhage,³ hypoxia, prematurity,^3–5 and neonatal care^3,6 have been reported to affect the developing brain; the mechanism of injury during the development of the cerebellum and corpus callosum in surviving premature infants may be caused by primary destruction or underdevelopment⁷ and axonal injury,⁸ respectively. These factors in turn result in an altered brain volume or structure that can be seen as a reduced cerebral and/or cerebellar volume,^3,9,10 subarachnoid space widening,^3,6,11 corpus callosum thinning,^12–14 and posthemorrhagic ventricular dilation on brain MR imaging.¹⁵ These findings have led to reports of various measurements of MR imaging as potential predictors of neurologic outcomes at infancy or in childhood.^10,14,16,17We conducted a study in a single neonatal intensive care unit (NICU) to evaluate correlations between brain MR imaging measurements taken at term-equivalent age and the neurodevelopmental outcomes at 2 years'' corrected age.