Neurodevelopmental Outcomes in Preterm Infants with White Matter Injury Using a New MRI Classification

Abstract

Objective: The aim of this study was to evaluate whether a new MRI scoring system for preterm non-haemorrhagic white matter injury (WMI), derived from the analysis of the natural evolution of WMI throughout the neonatal period until term-equivalent age, can be used for outcome prediction. Methods: Eighty-two infants <36 weeks gestation with WMI diagnosed from sequential cranial ultrasound and confirmed on neonatal MRI were retrospectively included. WMI was classified in four grades of severity. Neurodevelopmental data at a median age of 24 months were analysed. Results: In 74 surviving children WMI severity was strongly associated with the presence and severity of cerebral palsy (CP) and other neurodevelopmental impairments (Spearman's rank correlation 0.88, p < 0.001). Only 3 children with grade I WMI (9%) developed CP (all ambulant) and their developmental scores were not different to those from the controls, although they started walking significantly later (p = 0.036). Of the 6 children with grade II, 83% developed CP (mild in most), whereas 91% of the 34 children with grade III had CP (moderate-severe in 76%) and all had some degree of neurodevelopmental impairment. Three children with grade III WMI did not develop CP; their imaging showed, in contrast to children who developed CP, that the cysts did not affect the corticospinal tracts; also, myelin in the posterior limb of the internal capsule appeared normal in 2 children and suboptimal in 1. Conclusions: This MRI scoring system for preterm WMI can be used to predict neurodevelopmental outcomes. Individualized assessment of the site of lesions and the progression of myelination improves prognostic accuracy.