Over the last two decades there has been dramatic improvement in neonatal care, and now it is commonplace for high-risk neonates to survive well into adulthood.  However, this dramatic impact on mortality is hampered by the fact that a substantial portion of survivors go on to develop neurosensory, neurocognitive, and neuropsychiatric disabilities, impacting their quality of life, their family’s, and posing a large socioeconomic burden to society. Parallel to these outcome trends, there has been development, validation, and implementation of exciting innovative neurotherapeutic agents, including therapeutic hypothermia. The advent of multidisciplinary teams dedicated to the care of neonates with brain injury, now found in many of the large neonatal neurology centers, including places like UCSF, has also substantially impacted care. In Pittsburgh, our “Neuro-NICU team” includes a large cohort of neonatologists, two neonatal neurologists, and two  “neonatal” neuroradiologists, and provides coverage for two separate Level III NICUs in Western Pennsylvania. Our “Neuro-NICU” team conducts weekly conferences where neuroimaging (cranial ultrasound and MRI), laboratory results, and clinical data are reviewed together, generating consensus treatment plans as well as a fertile environment for training physicians. Additionally, by including research faculty in the conferences, these weekly meetings have become a catalyst for clinical research and an important conduit for translating research into clinical practice. In the near future, we may also see an even closer integration between neonatology and neuroradiology, as MR scanners are now being placed inside the NICU, a trend that was first started in England by the Hammersmith group and has now extended to the United States (at Cincinnati Children’s and Boston Children’s).

What does this mean for the specialty of neonatal neuroradiology? It

means that it is an exciting and very important time for practicing neuroradiologists as we move toward being an integral part of the clinical team caring for neonates with brain injury. Neuroimaging plays a central role in the management of these patients, and there are multiple aspects of neonatal brain injury for which advanced neuroimaging techniques can be used to answer important clinical questions. In the fourth issue of AJNR News Digest, we highlight some of the recent articles from multiple centers that are at the forefront of neonatal neuroimaging research and which demonstrate how neuroimaging is critical in improving the management of neonates with different forms of brain injury.

The first article uses traditional pattern recognition to correlate subtle white matter linear signal intensities with the distribution of deep medullary veins and different forms of neonatal brain injury. The next two articles use advanced neuroimaging techniques to further characterize brain injury in neonates with hypoxic-ischemic encephalopathy (HIE) treated with hypothermia. These two articles show how hypothermia alters metabolism (MRS), microstructure (DTI), and perfusion (ASL) following hypoxic-ischemic brain injury. These studies show that neuroimaging biomarkers derived from these sequences may provide key information regarding therapeutic outcomes and long-term prognosis. Furthermore, these techniques may help identify neonates with HIE who will require more aggressive therapies such as deeper hypothermia or adjuvant neuroprotective agents.

The next two articles focus on a special group of neonates, neonates with congenital heart disease (CHD), who not only face a substantial risk of neonatal mortality but also face substantial risk of long-term morbidity, including poor neurocognitive outcomes arising from white matter injury or other intracranial complications during the neonatal period. Again, using advanced neuroimaging techniques, these studies investigate the key connections in the developing brain—the interhemispheric connections through the callosum—to determine whether any of these connections are altered in the setting of a congenital heart lesion. These two studies, using different post-processing techniques of neonatal diffusion tensor imaging (tractography vs tract-based spatial statistics (TBSS)), show contrasting results between term and preterm neonates with congenital heart disease (CHD).  In the term neonatal CHD diffusion tensor study, the genu is shown to demonstrate vulnerability. In contrast, in the preterm neonatal CHD diffusion tensor study, the splenium is shown to demonstrate vulnerability after controlling for the effect of punctate white matter lesions.

The last article highlights a rare type of neonatal metabolic disorder, Krabbe disease. This study shows the true clinical translational value of advanced neuroimaging techniques, as diffusion tensor imaging is used to identify subtle abnormalities of the cortical spinal tract in neonates with Krabbe disease.  These imaging findings will eventually be used for earlier identification of Krabbe patients, who will benefit from life-saving unrelated umbilical cord transplantation.

The authors, in their own words, describe their original research and its impact on the clinical care of neonates with brain injury. The full articles can be downloaded at www.AJNR.org.

Image from: Escolar ML, Poe MD, Smith JK, et al. Diffusion Tensor Imaging Detects Abnormalities in the Corticospinal Tracts of Neonates with Infantile Krabbe Disease.