Neonatal cranial ultrasound: Current perspectives

Ultrasound is the most common imaging tool used in the neonatal intensive care unit. It is portable, readily available, and can be used at bedside. It is the least expensive cross sectional imaging modality and the safest imaging device used in the pediatric population due to its lack of ionizing radiation. There are well established indications for cranial ultrasound in many neonatal patient groups including preterm infants and term infants with birth asphyxia, seizures, congenital infections, etc. Cranial ultrasound is performed with basic grayscale imaging, using a linear array or sector transducer via the anterior fontanel in the coronal and sagittal planes. Additional images can be obtained through the posterior fontanel in preterm newborns. The mastoid fontanel can be used for assessment of the posterior fossa. Doppler images may be obtained for screening of the vascular structures. The normal sonographic neonatal cranial anatomy and normal variants are discussed. The most common pathological findings in preterm newborns, such as germinal matrix-intraventricular hemorrhage and periventricular leukomalacia, are described as well as congenital abnormalities such as holoprosencephaly and agenesis of the corpus callosum. New advances in sonographic equipment enable high-resolution and three-dimensional images, which facilitate obtaining very accurate measurements of various anatomic structures such as the ventricles, the corpus callosum, and the cerebellar vermis. Limited studies have been performed to predict that longitudinal measurements of these anatomic structures might predict the clinical outcome of high-risk preterm newborns. Hemodynamic Doppler studies may offer the potential for early intervention and treatment to counter the hazards of developmental delay and a moribund clinical outcome.