Intermittent flank pain or recurrent UTI, suspected UPJ obstruction (adult)
Recommended: Renal Ultrasound + MAG3 diuretic renogram is the preferred imaging study for intermittent flank pain or recurrent uti, suspected upj obstruction (adult). Crossing vessel or intrinsic stenosis.
Recommended study
Renal Ultrasound + MAG3 diuretic renogram
Crossing vessel or intrinsic stenosis. T1/2 > 20 min on MAG3 suggests obstruction.
If the default doesn't apply
Surgical planning
CT
CTA or MR Urography (look for crossing vessel)
IV contrast
Watch-outs
Intermittent symptoms
Pain after fluid load (Dietl crisis) — may be missed on routine imaging; provoke with diuretic.
Pearls
- Whitaker test (urodynamic): pressure / flow studies for ambiguous cases.
- Crossing lower pole vessel in 20-50% — surgical relevance.
- Pyeloplasty (open / lap / robotic) is definitive treatment.