Easily overlooked sonographic findings in the evaluation of neonatal encephalopathy: lessons learned from magnetic resonance imaging.

Findings of neonatal encephalopathy (NE) and specifically those of hypoxic-ischemic injury are frequently evident on magnetic resonance imaging (MRI). Although MRI has become more widely used and has gained widespread acceptance as the study of choice for the evaluation of NE in recent years, its costs are high and access to MRI is sometimes limited for extremely sick neonates. Therefore, head sonography (US) continues to be the first-line imaging modality for the evaluation of the brain in neonates with NE; furthermore, in many of these infants, the diagnosis of NE may have first been made or suggested using head US. US is noninvasive, inexpensive, and portable, allowing examinations to be performed without moving the infant. However, many of the telltale signs of NE on US are subtle and may be easily overlooked, contributing to diagnostic delay or misdiagnosis. We aim to illustrate the spectrum of US findings in NE, with emphasis on those findings that may be easily overlooked on US. Recognition of these findings could potentially improve detection rates, reduce errors, and improve patient management.