The main disadvantage of radionuclide cystography is that it does not provide anatomical details of the bladder and urethra and therefore should not be used as the first study for male patients. Therefore, arguments for and against using radionuclide cystography are similar to that of VCUG with the exception of male patients. DTPA Renal Scan There is no relevant literature to support the routine use of Tc-99m DTPA renal scan as the first imaging in the evaluation of mild antenatal hydronephrosis, because there is low risk of underlying anatomic abnormality such as UPJO in the setting of mild hydronephrosis. MAG3 Renal Scan There is no relevant literature to support the routine use of Tc-99m MAG3 diuretic renal scan as the first imaging in the evaluation of mild antenatal hydronephrosis, because there is low risk of underlying anatomic abnormality such as UPJO in the setting of mild hydronephrosis. MRI abdomen and pelvis There is no relevant literature to support the routine use of MRU in the initial evaluation of mild antenatal hydronephrosis. VUR can be either primary or secondary to other urologic abnormalities. In male patients with moderate or severe hydronephrosis found on neonatal US, VCUG has a role in the evaluation of urologic abnormalities that may need immediate care, and bladder outlet obstruction from PUV must be excluded [12,20,28,29,50,57]. The catheter placed for initial bladder decompression can be used for this study. There is no need to remove the bladder catheter to assess for PUV [58]. Frequently, the study will show VUR in addition to bladder wall thickening and the dilated posterior urethra. When the diagnosis of PUV is made, immediate referral to urology is needed. Furthermore, it can reveal other anomalies such as a duplex collecting system, which helps to determine whether the reflux is primary or secondary. Other infants with severe or bilateral moderate antenatal hydronephrosis may have VUR in isolation.
Antenatal Hydronephrosis Infant. The main disadvantage of radionuclide cystography is that it does not provide anatomical details of the bladder and urethra and therefore should not be used as the first study for male patients. Therefore, arguments for and against using radionuclide cystography are similar to that of VCUG with the exception of male patients. DTPA Renal Scan There is no relevant literature to support the routine use of Tc-99m DTPA renal scan as the first imaging in the evaluation of mild antenatal hydronephrosis, because there is low risk of underlying anatomic abnormality such as UPJO in the setting of mild hydronephrosis. MAG3 Renal Scan There is no relevant literature to support the routine use of Tc-99m MAG3 diuretic renal scan as the first imaging in the evaluation of mild antenatal hydronephrosis, because there is low risk of underlying anatomic abnormality such as UPJO in the setting of mild hydronephrosis. MRI abdomen and pelvis There is no relevant literature to support the routine use of MRU in the initial evaluation of mild antenatal hydronephrosis. VUR can be either primary or secondary to other urologic abnormalities. In male patients with moderate or severe hydronephrosis found on neonatal US, VCUG has a role in the evaluation of urologic abnormalities that may need immediate care, and bladder outlet obstruction from PUV must be excluded [12,20,28,29,50,57]. The catheter placed for initial bladder decompression can be used for this study. There is no need to remove the bladder catheter to assess for PUV [58]. Frequently, the study will show VUR in addition to bladder wall thickening and the dilated posterior urethra. When the diagnosis of PUV is made, immediate referral to urology is needed. Furthermore, it can reveal other anomalies such as a duplex collecting system, which helps to determine whether the reflux is primary or secondary. Other infants with severe or bilateral moderate antenatal hydronephrosis may have VUR in isolation.