Longitudinal change in white matter in preterm infants without magnetic resonance imaging abnormalities: Assessment of serial diffusion tensor imaging and their relationship to neurodevelopmental outcomes

Purpose: We used diffusion tensor imaging (DTI) to evaluate longitudinal changes in fractional anisotropy (FA) of white matter tracts in preterm infants without abnormal magnetic resonance imaging (MRI) findings. Imaging was conducted at term equivalent age (TEA) and 1 year of corrected age. Furthermore, we assessed correlations between FA and neurodevelopmental outcomes at 3 years of corrected age to investigate brain prematurity of preterm infants without MRI abnormalities. Methods: Preterm infants underwent serial MRI at TEA and 1 year of corrected age. Of these, 13 infants entered a retrospective study, undergoing neurodevelopmental assessment at 3 years of corrected age. These infants were divided into two groups depending on gestational age (GA): <26 weeks and >= 26 weeks. DTI-based tractography was performed to obtain the FA of the motor tract, sensory tract, superior cerebellar peduncle, middle cerebellar peduncle, and corpus callosum. FA was compared between two groups, and correlations between FA and neurodevelopmental outcomes were assessed. Results: FA of the splenium at TEA was significantly different between the two groups divided according to GA. However, this difference was no longer observed at 1 year of corrected age. There was no correlation between FA of the splenium at TEA and neurodevelopmental assessment scores at 3 years of corrected age. Conclusions: At TEA, FA of the splenium was lower in younger GA infants without MRI abnormalities, but this may not affect subsequent neurodevelopmental outcomes. (C) 2016 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.