There is higher risk for UTI in children with VUR [59]. Although the benefit of prophylactic antibiotics in this population is unknown, some authors recommend beginning antibiotics on these patients [26,60]. Voiding Urosonography Multiple recent investigations evaluating real-time contrast-enhanced US techniques have demonstrated a high degree of diagnostic accuracy, and some demonstrated increased sensitivity compared to fluoroscopic VCUG in the detection of VUR [41-45]. However, given the significant disadvantage of voiding urosonography in providing lower anatomical detail of the bladder and urethra, it should not be used as the first study for male patients. Nuclear Medicine Cystography Although some studies have suggested equal sensitivity for Tc-99m pertechnetate radionuclide cystography and VCUG [46], it does not provide sufficient anatomical detail of the bladder and urethra and therefore should not be used as the first study for male patients. DTPA Renal Scan Tc-99m DTPA is excreted primarily by glomerular filtration. Its extraction fraction is approximately 20% accounting for greater background, versus renal, activity compared to MAG3 [61]. Tc-99m DTPA renal scan provides information on renal function and urinary tract drainage based on split renal function and renal washout curves and can be useful for the evaluation of severe grade 3 and 4 hydronephrosis in concert with VCUG [20,29,53,62,63]. Given the lower glomerular filtration rate in newborns, these examinations are frequently delayed until at least 2 months of age [29,63-65]. However, because of its rapid renal clearance and primary excretion by the tubules on which furosemide acts, Tc-99m MAG3 is preferred over Tc-99m DTPA in patients with suspected obstruction or impaired renal function [61]. MAG3 Renal Scan Tc-99m MAG3 is primarily excreted through active renal tubular transport, and its extraction fraction is 40% to 50% [61].
Antenatal Hydronephrosis Infant. There is higher risk for UTI in children with VUR [59]. Although the benefit of prophylactic antibiotics in this population is unknown, some authors recommend beginning antibiotics on these patients [26,60]. Voiding Urosonography Multiple recent investigations evaluating real-time contrast-enhanced US techniques have demonstrated a high degree of diagnostic accuracy, and some demonstrated increased sensitivity compared to fluoroscopic VCUG in the detection of VUR [41-45]. However, given the significant disadvantage of voiding urosonography in providing lower anatomical detail of the bladder and urethra, it should not be used as the first study for male patients. Nuclear Medicine Cystography Although some studies have suggested equal sensitivity for Tc-99m pertechnetate radionuclide cystography and VCUG [46], it does not provide sufficient anatomical detail of the bladder and urethra and therefore should not be used as the first study for male patients. DTPA Renal Scan Tc-99m DTPA is excreted primarily by glomerular filtration. Its extraction fraction is approximately 20% accounting for greater background, versus renal, activity compared to MAG3 [61]. Tc-99m DTPA renal scan provides information on renal function and urinary tract drainage based on split renal function and renal washout curves and can be useful for the evaluation of severe grade 3 and 4 hydronephrosis in concert with VCUG [20,29,53,62,63]. Given the lower glomerular filtration rate in newborns, these examinations are frequently delayed until at least 2 months of age [29,63-65]. However, because of its rapid renal clearance and primary excretion by the tubules on which furosemide acts, Tc-99m MAG3 is preferred over Tc-99m DTPA in patients with suspected obstruction or impaired renal function [61]. MAG3 Renal Scan Tc-99m MAG3 is primarily excreted through active renal tubular transport, and its extraction fraction is 40% to 50% [61].