Magnetic resonance techniques in the evaluation of the newborn brain

MR imaging provides unequaled sensitivity as compared with US or CT scanning for evaluating developmental changes and pathologic processes in the newborn brain. Myelination can be assessed qualitatively and quantitatively using newer 3D-MR imaging methods. MR imaging provides a much clearer delineation of many developmental disorders, including anomalies of migration and organization, as well as a variety of metabolic disorders and congenital infections. Neonatal intracranial hemorrhage is detected in all its locations by MR imaging. The timing of the hemorrhage is a unique feature of MR imaging. Venous thrombosis also can be identified by MR imaging and confirmed with MR angiography. HIE is the major cause of potentially preventable or reversible brain injury that results in considerable long-term neurologic morbidity. Early detection is crucial for interventions aimed at preventing or reversing ongoing injury. DWI can show early changes at the cellular level that are not detectable by any other imaging modality. MR spectroscopy has further opened the possibility of studying the metabolic mechanisms that define the pathophysiologic events taking place in neonatal brain injury. Both 31P-MR spectroscopy, as a marker of the acute changes in energy metabolism, and 1H-MR spectroscopy, with the measurement of lactate and the excitotoxic aminoacids glutamate and glutamine, have enabled us to study the early and late effects of insults to the newborn brain in a noninvasive fashion. Studies performed to determine the predictive value of MR spectroscopy for later neurodevelopmental outcome after HIE have shown promising results but need further evaluation on larger patient samples. The potential use of these methods in the evaluation of early neuroprotective treatment regimens in the newborn remains to be determined.