Sensitivity of ultrasonography in detecting renal parenchymal defects in children.

Renal parenchymal defects (RPD) -- scars, hypoplasia/dysplasia -- in children are a major risk factor for chronic renal failure. Most authors would agree that RPD should be detected and followed by a 99mTc-dimercaptosuccinic acid renal scan (DMSA), as ultrasonography (US) does not seem to be sensitive enough for this purpose. However, it might well be that DMSA is too sensitive and detects RPD that are too small to be clinically significant. The purpose of this study was to evaluate the sensitivity of US in identifying patients with clinically significant RPD and in detecting RPD of various grades as seen by DMSA. In 89 children with abnormal DMSA, a second DMSA, US, and other tests for evaluating renal function were performed at least 1 year after the first DMSA. The extent of RPD detected by DMSA and US was correlated with renal function parameters. In all 5 patients with diminished renal function, RPD were detected by both DMSA scan and US. In addition, US detected clinically insignificant RPD in 48 of 67 cases (71.6%). The present study has shown that, compared with DMSA, US is sensitive enough to detect clinically significant RPD in children. The substitution of DMSA with US would be beneficial, as this would eliminate radiation exposure, reduce costs, and increase availability.