Patient with prenatal hydronephrosis. Lasix renography.

Case presentation:

• Male.
• 3 month old.
• Second pregnancy. 
• 20 w US: LK HN, pelvis 22 mm.
• After delivery: a. US performed day 7th: persistent LK HN. b. LK: Increased size.Pelvis 25 mm . Thin parenchyma.

Teaching points:

• In case of severe hydronephrosis, activity can persist in the dilated system on the DMSA images obtained 4 hours after tracer injection.
• In these cases, it is advisable to obtain delayed DMSA images, 24 hours after injection.