Magnetic resonance imaging in perinatal brain injury: clinical presentation, lesions and outcome.

Neonatal MR imaging is invaluable in assessing the term born neonate who presents with an encephalopathy. Successful imaging requires adaptations to both the hardware and the sequences used for adults. The perinatal and postnatal details often predict the pattern of lesions sustained and are essential for correct interpretation of the imaging findings, but additional or alternative diagnoses in infants with apparent hypoxic ischaemic encephalopathy should always be considered. Perinatally acquired lesions are usually at their most obvious between 1 and 2 weeks of age. Very early imaging (<3 days) may be useful to make management decisions in ventilated neonates, but abnormalities may be subtle at that stage. Diffusion-weighted imaging is clinically useful for the early identification of ischaemic white matter in the neonatal brain but is less reliable in detecting lesions within the basal ganglia and thalami. The pattern of lesions seen on MRI can predict neurodevelopmental outcome. Additional useful information may be obtained by advanced techniques such as MR angiography, venography and perfusion-weighted imaging. Serial imaging with quantification of both structure size and tissue damage provides invaluable insights into perinatal brain injury.