Tc-99m DMSA renal scintigraphy during kidney maturation.

A total of 282 renal scintigrams with Tc-99m DMSA in 238 children ranging in age from 10 days to 13 years performed during a 3-year period were reviewed. The authors present 94 kidneys in 85 children in whom no sign of pathology was demonstrated clinically, either by ultrasound or intravenous urography, or by micturating urethrocystography. By exploring homogeneity or heterogeneity of tracer distribution, kidney length, and background level, the authors were able to identify a "normal" pattern of tracer distribution according to age. They found that the average kidney length was 56 mm at birth, growing 1 mm per month during the first year of life, and 4 mm per year thereafter, until puberty. Average background activity was 14% of the average kidney activity at birth which decreased to approximately 6% during the first year of life, with no further decrease thereafter.