Objective: The aim of this study was to assess the additional value of diffusion-weighted magnetic resonance imaging (DW-MRI) compared to conventional magnetic resonance imaging (MRI) in new-born infants with arterial ischaemic stroke, with regard to the prediction of neurodevelopmental outcome.
Methods: Neonatal DW-MRI data were available in 15 infants with a gestational age of > or = 35 weeks and repeat MRI data were obtained in 12 of the 14 survivors. T(1)- and T(2)-weighted transverse images were obtained as well as 4-mm DWI slices. ADC maps were calculated in manually selected regions on the basis of the DWI scans. All 14 survivors were seen in the follow-up clinic and 12 were > 18 months when last seen.
Results: T (2) hyperintensity was detected in the descending white matter tracts at the level of the internal capsule in 7 infants and in only one of these also at the level of the cerebral peduncles. Increased signal intensity (SI) was seen on DW-MRI in 8 infants in the descending white matter tract ipsilateral to the territorial infarct at the level of the internal capsule and in 5 of these also at the level of the cerebral peduncles. ADC maps were available in 12 infants. ADC values were calculated at the level of the cerebral peduncles, using the contralateral side as a reference value. A significantly reduced value was found in 3 of the 5 infants who showed an increased SI on DW-MRI. ADC maps were not available in the other two. Five of the seven infants with abnormalities on DW-MRI/ADC of the corticospinal tracts developed a mild to moderate hemiplegia, one showed an asymmetry of tone and one with only involvement of the anterior part of the internal capsule was normal at follow-up. Wallerian degeneration, seen at the level of the cerebral peduncles and/or the PLIC on the repeat MRI, was seen in the 5 infants who had shown acute changes of the corticospinal tracts in the neonatal period and who went on to develop motor sequelae.
Conclusions: Compared to MRI, DW-MRI and ADC maps provided additional, quantitative data of acute corticospinal tract injury at an early time point after the insult, especially at the level of the cerebral peduncles. The presence of increased SI on DW-MRI at the level of the PLIC and the cerebral peduncles in new-born infants with arterial ischaemic stroke is followed by Wallerian degeneration and subsequent development of hemiplegia.