Cranial ultrasound for beginners.

Cranial ultrasound (CUS) is an extremely valuable tool to evaluate the brain during the first year of life, in experienced hands. It is the initial screening imaging tool to evaluate the infants' brain and complementary to the use of computed tomography (CT) and magnetic resonance imaging (MRI). It is an accessible, inexpensive and harmless technique that can be used bedside as frequently as needed. The aim of this article is to provide a guide for beginners about the indications, basic technical parameters, scanning technique, standardized planes, common variants and the most frequent abnormal findings visualized with this technique. This article will explain a systematic technique to adequately visualize and document all the relevant intracranial structures, using the anterior fontanelle, mastoid fontanelle and Doppler ultrasound. The variants described in this review include the normal sulcation of the premature baby, the peritrigonal echogenic "blush", lenticulostriate vasculopathy (LSV), benign enlargement of the subrarachnoid space in infancy, asymmetric lateral ventricles, connatal cysts, cavum septum pellucidum (CSP), cavum vergae (CV), cavum velum interpositum, megacisterna magna and choroid plexus cysts. This article will describe the sonographic appearance of different types of intracranial hemorrhage of the preterm and term baby, periventricular leukomalacia (PVL), central and peripheral hypoxic-ischemic events of the term baby, neonatal arterial infarction, cerebro-venous sinus thrombosis, congenital and neonatal cerebral infections, hydrocephalus, intracranial solid and cystic masses, and congenital brain malformations.