Scinтigraphy in Children with Urinary Tract Dilatation (Antenatally Detected Hydronephrosis)

Abstract

The causes of Antenatal Hydronephrosis/Urinary Tract Dilatation (ANH/UTD) vary from transient benign conditions-transit hydronephrosis, (resolves by birth or during infancy) to conditions that can significantly affect renal function. The outcome of depends on the underlying etiology, so it is very important to determine these causes. The definition and grading of ANH is based on the Anteroposterior Pelvic Diameter (APD) of the fetal renal pelvis. Antenatal management includes antenatal ultrasound monitoring, which is usually repeated every 4-6 weeks. It is recommended that the assessment of the severity of postnatal hydronephrosis is based on the APD of the renal pelvis. Extensive postnatal investigation was proposed to be limited to those with moderate or severe dilatation. Voiding cystourethrography and scintigraphy are usually preserved for children with postnatal APD <15 mm and/or abnormal kidney parenchyma, severe caliyx dilatation ureteral dilatation and bladder pathology. Diuretic renal scintigraphy is important in the postnatal evaluation of infants with ANH, particularly in distinguishing kidneys with poor drainage from nonobstructive hydronephrosis with good drainage. According to our diuretic renography results, we conclude that in the presence of partial or no drainage, the separate renal function may not be significantly impaired. The finding of poor renal emptying is significantly more common among children with increasing renal pelvis APD. Technetium 99m-dimercaptosuccinic acid renal scintigraphy (99mTc-DMSA) has been used in renal imaging to estimate the functional renal mass (damage to the kidney) and relative renal function, especially in pediatric patients. A statistically significant correlation between the degree of hydronephrosis (APD) and DMSA scan finding and between the degree of the VUR and DMSA scan finding was established. Other than VUR, CAKUT (pelvic ureteric junction obstruction, pyelon et ureter duplex, megaureter, posterior urethra valves) were not statistically correlated with pathological findings on the DMSA scan.