The role of renal contour change in the diagnosis of cortical scarring after urinary tract infection.

Urinary tract infections in children can lead to permanent renal scarring in approximately 15% of cases. Technetium-99m (Tc)-dimercaptosuccinic acid (DMSA) scintigraphy is the gold standard for identifying renal scarring. Using data and scans from children enrolled at our center in a 2-year prospective clinical trial (RIVUR study), we included children with radiologically confirmed pyelonephritis who exhibited renal scarring on their 1 and/or 2-year follow-up scans and asked 3 blinded pediatric nuclear medicine physicians to reexamine the renal contours in these scans. Five girls met all eligibility criteria (each had two late Tc-DMSA scans 1 and 2 years after index UTI). Of the 20 kidneys imaged, 10 exhibited renal scarring and of these, 7 exhibited renal contour abnormalities. These findings suggest that the presence of abnormalities of the renal contour is not necessary for diagnosis of renal scarring.