Usefulness of lower-dose computed tomography urography with iterative reconstruction technique in diagnosis of congenital anomalies in urinary tract in children.

Introduction of iterative reconstruction technique in modern computed tomography allowed to reduce the radiation dose and to extend indications for computed tomography urography in children. We describe the case of boy with congenital anomalies in urinary tract including bilateral double collecting system, dilatation of double collecting system in the right kidney and dilatation of lower pelvis in left kidney and bilateral dilatation of ureters. Anomalies were detected in prenatal and then confirmed in postnatal ultrasonography. Voiding cystourethrograhy, which was performed on the 4th day of life revealed grade IV vesicoureteral reflux to the lower part of double collecting system in the right kidney and grade V vesicoureteral reflux to the left kidney. In cystoscopy posterior urethral valves were excluded and presence of double ureters was confirmed. Dynamic scintigraphy (99mTc-EC) detected impaired parenchymal secretory function in the lower pole of left kidney. The patient was qualified for surgical treatment including left lower heminephoureterectomy. Before surgery procedure computed tomography urography was performed and revealed congenital anomalies in urinary tract: bilateral double collecting system, bilateral hydronephrosis of the lower part of kidneys, dilatation of ureters associated with high grade of vesicoureteral refluxes, narrow cortex of left kidney. Computed tomography urography with iterative reconstruction techniques enables precise visualization of urinary tracts with reduced radiation dose. It replaces conventional X-ray urography because of much better visualization of urinary tracts with comparable or even lower radiation dose.