Objective Magnetic resonance imaging (MRI) at term age has been reported to be superior to cranial ultrasound (cUS) in detecting white matter abnormalities and predicting outcome in preterms (Woodward et al, N Engl J Med 2006). However, in that study cUS was performed only during the first 6 weeks and not parallel to MRI at term age. Therefore, we aimed to study brain injury in preterms with both MRI and cUS performed at term age.

Methods In a population-based cohort of 72 extremely low gestational age (ELGA) infants paired cranial cUS and MRI were performed at term age. Abnormalities on MRI were graded according to a previously published scoring system (Woodward et al, N Engl J Med 2006). On cUS the size of lateral ventricles, the corpus callosum, the interhemispheric fissure and the subarachnoidal spaces were measured; the presence of cysts and gyral folding was scored.

Results Moderate–severe white matter abnormalities were detected on MRI in 17% and abnormal grey matter in 11%. Among infants with normal ultrasound (n  =  28) none had moderate–severe white matter abnormalities or abnormal grey matter on MRI. All infants with severe white matter abnormalities on MRI (n  =  3) were graded as severe on cUS.

Conclusion All infants with severe white matter abnormalities identified on MRI at term age were also detected by cUS, providing it was performed on the same day as MRI. Infants with normal ultrasound at term age were found to have a normal MRI at term or only mild white matter abnormalities.