Renal ultrasound in the neonatal period.

Ultrasound was used for imaging the kidneys in 55 neonates. The normal kidney in a neonate is characterized by prominent medulla and fetal lobulation, the main renal vessels are frequently demonstrated. Of 29 infants with normal kidneys by ultrasound, 4 had renal disease (3 acute tubular necrosis, one partial renal artery thrombosis) and one had a pelvic kidney. In 24 infants congenital abnormalities or acquired renal disease was diagnosed. Multicystic dysplastic kidney and hydronephrosis were the most frequently observed abnormalities. Polycystic kidneys at the early stage (both adult type and infantile) appeared as enlarged hyperechoic kidneys. In 2 neonates the kidneys were normal but they had adrenal mass lesions.