Cranial sonography in term and near-term infants.

Sonographic patterns of brain injury in the term and near-term infant are quite different from those in the premature infant. Although periventricular leukomalacia and germinal matrix hemorrhage are rarely seen in term infants, selective neuronal injury, parasagittal infarction, focal stroke, diffuse hypoxic-ischemic injury, and deep parenchymal hemorrhages are more common lesions. In addition, congenital brain tumors, hamartomatous lesions, such as hemimegalencephaly, and tuberous sclerosis can mimic ischemic and hemorrhagic injury. Sonography remains an important tool in the initial evaluation of intracranial abnormalities in critically ill term and near-term infants. An understanding of the differences in etiology, sonographic patterns, and limitations of sonography in the term infant is essential for accurate and effective diagnoses in this age group.