The interrenicular junction: a mimic of renal scarring on normal pediatric sonograms.

A triangular, echogenic focus of perirenal tissue in the anterosuperior or posteroinferior margin of the kidney, the junctional parenchymal defect (JPD), and an oblique echogenic line, the interrenicular septum (IRS), connecting the JPD to the renal hilum are normal sonographic findings in the pediatric age group. They are manifestations of an oblique interface between the two parts (reniculi) of one kidney. They should not be mistaken for renal scars. Prospectively, in a group of 100 children, either the JPD or IRS was seen in 46% of right kidneys and 19% of left kidneys. Retrospectively, the JPD was seen in 47% of right kidneys and 18% of left kidneys, and the IRS was seen in 39% of right kidneys and 12% of left kidneys.