Diuretic renography in hydronephrosis: a retrospective single-center study

Area of Science:

• Pediatric Nephrology
• Diagnostic Imaging
• Urology

Background:

• Ureteropelvic junction obstruction (UPJO) is a common cause of pediatric hydronephrosis.
• Mercaptoacetyltriglycine-3 diuretic renography (MAG3) assesses differential renal function (DRF) and drainage in UPJO.
• Ultrasound (US) is a primary imaging modality for hydronephrosis, but its ability to predict functional outcomes needs further clarification.

Purpose of the Study:

• To evaluate if anteroposterior pelvic diameter (APD) on renal US can predict DRF and obstruction in pediatric UPJO.
• To determine if US findings can identify children requiring further investigation.
• To compare US and MAG3 findings in a larger pediatric cohort.

Main Methods:

• Retrospective review of MAG3, US, and dimercaptosuccinic acid scan (DMSA) findings.
• Analysis of medical records for pediatric patients with hydronephrosis between 2013 and 2016.
• Inclusion of 225 pediatric patients with unilateral hydronephrosis without VUR.

Main Results:

• An APD > 20 mm was associated with a 15.8-fold increased likelihood of obstruction on MAG3.
• An APD > 15 mm was associated with a 9.2-fold increased likelihood of obstruction on MAG3.
• An APD > 20 mm was a significant risk factor for low DRF (OR=5.208), while APD > 15 mm was not.

Conclusions:

• A 20 mm APD threshold on US is more reliable for predicting severe obstruction and low DRF than a 15 mm threshold.
• US, particularly APD measurement, can aid in identifying pediatric UPJO patients needing further functional assessment with MAG3.
• Combined US and MAG3 provide comprehensive anatomical and functional data for managing pediatric UPJO.