Background

MRI is a relatively new and evolving technology—the first human scans were performed in the late 1970s,1 and the first neonatal brain scans followed shortly after in the early 1980s.2 Since then, the typical magnetic field strength used in clinical scanners has increased from approximately 0.15 Tesla to 1.5–3 Tesla, making higher resolution imaging possible, which is particularly important for the small anatomical structures in the neonatal brain. A variety of different MRI modalities are now possible, with both research and clinical applications (table 1).

Performing MRI scans in neonates can be technically challenging for a number of reasons: (1) size—the average brain volume of a term newborn is a quarter of an adult brain, requiring higher resolution to clearly delineate structures; (2) movement—motion corruption can lead to unusable images; babies are unable to follow instructions to lie still, and the combination of a noisy machine and unfamiliar environment can make it difficult to remain asleep; (3) physiology—higher resting heart rates and respiratory rates in neonates require careful adaptation of cardiac and flow-based imaging; and (4) biological differences—the immature brain has a higher water content and more unmyelinated white matter compared with adults, resulting in different tissue contrast from that of the adult brain and hence the need to optimise sequences accordingly.

To enable safe scanning of smaller and sicker neonates, a few research groups worldwide have colocated scanners directly on the …