Embryology, Sex Differentiation, and Gonad Differentiation Overview. The three important precursor components needed for genital system development are the genital ridge and the two sets of internal sex ducts, the Müllerian-paramesonephric and the Wolffian-mesonephric. Around 7 weeks' gestation, the embryologic…
Renal Injury Overview. The kidney is the third most frequently injured abdominal viscus in children and accounts for 1.3% to 15% of injuries in children who suffer blunt abdominal trauma. Children are more susceptible to renal injury during blunt trauma…
Neuroblastoma Overview. Neuroblastoma is the most common extracranial solid neoplasm in children and accounts for almost 10% of all childhood neoplasms. Neuroblastoma arises in the abdomen in two-thirds of cases; of these, about two-thirds of lesions occur in the adrenal…
Normal Adrenal The adrenal glands in the neonate are easily visualized on ultrasonography; they are relatively large because of the presence of the fetal adrenal cortex, which accounts for about 80% of the gland ( Fig. 121.1 ). On ultrasonography,…
Urachal Anomalies Overview. The urachus is the fetal channel connecting the bladder and the allantosis. Fibrotic regression of the urachus typically extends from the umbilicus toward the bladder and results in the median umbilical ligament. Usually, this process is completed…
Definition and Imaging Objectives Overview. Vesicoureteral reflux (VUR) refers to the retrograde passage of urine from the urinary bladder into the ureter and often to the renal collecting system. VUR mainly affects infants and young children with a prevalence of…
Embryology During the fifth week of gestation, the urinary collecting system begins development as an outpouching from the mesonephric duct known as the ureteral bud. Contact between the bulbous portion of the ureteral bud and the metanephric blastema induces this…
Acute Renal Injury Overview. Acute renal failure is defined as a sudden loss of renal function that may be due to inadequate renal perfusion, renal cell injury, or obstruction to urine flow. The term acute kidney injury (AKI) has been…
Renovascular Hypertension Overview. Approximately 5% to 10% of children and adolescents with severe hypertension have an underlying renal vascular lesion. In children younger than 5 years, up to 80% of clinically significant hypertension is due to renovascular disease. There are…
Nephrogenic Rests and Nephroblastomatosis Overview and Pathophysiology. Embryologic development of the kidneys is completed by the 36th gestational week. Residual embryonic fetal tissue (metanephric blastema) that persists beyond 36 weeks' gestation is called a nephrogenic rest . Multifocal or diffuse…