Purpose or Case Report: Ultrasound is the most accessible and reliable modality to evaluate the kidneys in neonates and young infants. The sonographic appearance of the kidneys in the immediate postnatal period can differ significantly from that in older children and adults. In clinical practice, radiologists encounter a full spectrum of renal pathology, with some appearing as hyperechogenicity on ultrasound. The purpose of this case-based educational exhibit is to provide a review of normal and abnormal causes of increased echogenicity of the kidneys in neonates and young infants, and common sonographic pitfalls that can artificially increase renal echogenicity
Methods & Materials: This educational exhibit provides a brief review of the unique sonographic characteristics of the kidneys in neonates and young infants and pitfalls when imaging including artifacts and technical factors. We review the normal sonographic appearances of the kidneys in neonates and young infants that correspond with natural physiologic events. Furthermore, the imaging features of hyperechoic renal pathology will be depicted along with pertinent information regarding each corresponding disease entity. The pathologies described include ureteropelvic junction obstruction, renal vein thrombosis, acute tubular necrosis, autosomal recessive polycystic disease (ARPKD), autosomal dominant polycystic kidney disease (ADPKD), cystic renal dysplasia, Beckwith-Widenemann syndrome, Candida infection, congenital nephrotic syndrome, and medullary nephrocalcinosis.
Results: The normal neonatal kidney can demonstrate distinct sonographic features which differ significantly from older children and adults potentially mimicking pathology. Various physiologic and pathologic causes can result in increased echogenicity of the kidneys in neonates and young infants.
Conclusions: Recognition and comprehension of the normal and abnormal sonographic appearance of the kidneys in neonates and young infants, as well as sonographic imaging pitfalls, is crucial to accurate diagnosis and patient management of renal pathology.