Toward quantitative MRI analysis: A smart approach to characterize neonatal white matter injury.

Abstract

Brain injury in preterm infants, as demonstrated with neonatal MRI, is associated with adverse neurodevelopmental outcomes in cognitive, language, motor, educational, behavioral, and social domains.1 Such brain injury is heterogeneous, is rarely localized, and evolves over time. White matter injury (WMI) in preterm infants is by far the most frequent brain injury, and occurs in over 70% of preterm infants born before 31 weeks of gestation.2 WMI found in the preterm brain includes cystic lesions, focal small lesions with high signal intensity (best seen on T1-weighted images), diffuse excessive high signal intensity (DEHSI), and loss of white matter volume. Although classic cystic periventricular leukomalacia is becoming rarer, DEHSI is seen often, and is obvious at term-equivalent age (TEA). Its specific relevance is open for debate, with poor predictive value for 2-year outcomes.3 However, qualitative MRI analysis assessing loss of substance (white matter atrophy, ventricular dilation, and associated corpus callosum thinning) at TEA is able to predict 2-year outcomes.4 In this era of active research for new neuroprotective therapies in the neonatal period, robust comprehensive approaches are warranted not just to predict the consequences of injury, but also to identify newborns who could benefit from future targeted neuroprotective therapies. So far, only a handful of systematic qualitative or quantitative MRI approaches have been evaluated or used to assess therapeutic efficiency.5,6