Fluoroscopy Antegrade Pyelography There is limited evidence to support the use of fluoroscopic antegrade pyelography for initial imaging of patients with asymptomatic bilateral hydronephrosis or asymptomatic hydronephrosis in a solitary kidney with unknown cause. Fluoroscopy Voiding Cystourethrography There is limited evidence to support the use of fluoroscopic voiding cystourethrography for initial imaging of patients with asymptomatic bilateral hydronephrosis or asymptomatic hydronephrosis in a solitary kidney with unknown cause. Hydronephrosis on Prior Imaging-Unknown Cause MAG3 Renal Scan DRG is the de facto standard of care in diagnosis of renal obstruction [10] and can be used to determine whether obstructive uropathy is truly present in cases of incidentally noted hydronephrosis or in suspected obstruction of renal transplant [11]. Further, DRG with urethral catheter has been suggested for patients with bilateral hydronephrosis or hydroureteronephrosis with postvoid residual <150 mL to help differentiate potential etiologies [2]. Tubular tracers (eg, MAG3 and 123I) are much more efficiently extracted by the kidney than DTPA, and washout is therefore easier to evaluate with tubular tracers. Tubular tracers such as MAG3 are favored over the use of DTPA for imaging only studies, because DTPA DRG may result in an equivocal or false-positive diuretic study compared with MAG3, particularly in patients with reduced function [11,12]. MRI Abdomen and Pelvis Without and With IV Contrast Although there is limited evidence to support the use of MRI abdomen and pelvis without and with IV contrast (separate from MRU) for initial imaging of patients with asymptomatic bilateral hydronephrosis or asymptomatic hydronephrosis in a solitary kidney with unknown cause, it may be useful in this setting in some clinical situations. More comprehensive evaluation can often be achieved with CT, MRU, or renal scintigraphy.
Hydronephrosis on Prior Imaging Unknown Cause. Fluoroscopy Antegrade Pyelography There is limited evidence to support the use of fluoroscopic antegrade pyelography for initial imaging of patients with asymptomatic bilateral hydronephrosis or asymptomatic hydronephrosis in a solitary kidney with unknown cause. Fluoroscopy Voiding Cystourethrography There is limited evidence to support the use of fluoroscopic voiding cystourethrography for initial imaging of patients with asymptomatic bilateral hydronephrosis or asymptomatic hydronephrosis in a solitary kidney with unknown cause. Hydronephrosis on Prior Imaging-Unknown Cause MAG3 Renal Scan DRG is the de facto standard of care in diagnosis of renal obstruction [10] and can be used to determine whether obstructive uropathy is truly present in cases of incidentally noted hydronephrosis or in suspected obstruction of renal transplant [11]. Further, DRG with urethral catheter has been suggested for patients with bilateral hydronephrosis or hydroureteronephrosis with postvoid residual <150 mL to help differentiate potential etiologies [2]. Tubular tracers (eg, MAG3 and 123I) are much more efficiently extracted by the kidney than DTPA, and washout is therefore easier to evaluate with tubular tracers. Tubular tracers such as MAG3 are favored over the use of DTPA for imaging only studies, because DTPA DRG may result in an equivocal or false-positive diuretic study compared with MAG3, particularly in patients with reduced function [11,12]. MRI Abdomen and Pelvis Without and With IV Contrast Although there is limited evidence to support the use of MRI abdomen and pelvis without and with IV contrast (separate from MRU) for initial imaging of patients with asymptomatic bilateral hydronephrosis or asymptomatic hydronephrosis in a solitary kidney with unknown cause, it may be useful in this setting in some clinical situations. More comprehensive evaluation can often be achieved with CT, MRU, or renal scintigraphy.