Cranial ultrasonography of the immature cerebellum: Role and limitations.

Cranial ultrasonography (CUS) is a reliable and non-invasive tool to detect frequently occurring brain abnormalities and to monitor brain development and maturation in high risk neonates. Standard CUS views are obtained through the anterior fontanel. However, evaluation of the posterior fossa is often suboptimal with this approach. Cerebellar injury occurs frequently in preterm infants and has important prognostic consequences. Early detection is therefore important. This review focuses on techniques that optimize the performance of CUS when studying the preterm cerebellum, including the use of the mastoid fontanel and the adaptation of focus points and scan frequencies. For illustration, CUS images of the normal posterior fossa anatomy as well as examples of abnormalities that may be encountered in preterm infants are included. We also discuss the limitations of CUS and the role of magnetic resonance imaging.