Differential Diagnosis of Echogenic Lesions at Neonatal Head US.

Head US is the mainstay of initial neuroimaging in preterm and term neonates and young infants. Echogenic lesions are a commonly encountered finding on US images, with a wide spectrum of underlying causes. These include normal structures and normal variants such as the choroid plexus and cerebellar vermis, normal transmantle white matter tracts, and benign entities that should not be mistaken for disease, such as hyperechoic caudate nuclei and thalamostriate mineralizing vasculopathy. Many pathologic conditions associated with major morbidity and mortality also may appear echogenic on US images. These most commonly include germinal matrix hemorrhage; white matter injury; hypoxic-ischemic encephalopathy; and hemorrhagic, infectious, and ischemic lesions. These lesions may be differentiated by their location at the caudothalamic groove, in the periventricular or deep white matter, diffusely involving the white matter, involving the deep gray matter, in the peripheral parenchyma, or in the cerebellum. Use of a tailored gestational age- and location-based approach combined with salient clinical details and knowledge of the unique vulnerabilities and responses to perinatal stressors in the preterm and term period improve diagnostic confidence and enable radiologists to differentiate those echogenic lesions that require no further follow-up from those that require further imaging or laboratory workup and specialist referral. ^©RSNA, 2025 Supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.