Sonographic measurement of diuretic-induced renal length changes: are they correlated with renal function?

Objectives: The purposes of this study were to prospectively identify diuretic-induced renal length changes and to determine whether the percentages of the renal length changes allow estimation of the differential renal function.
Methods: Twenty-three children (14 boys and 9 girls; mean age, 7.83 years) who were undergoing technetium Tc 99m diethylenetriamine pentaacetic acid or technetium Tc 99m mercaptoacetyltriglycine diuretic renography were included in this study. Renal lengths were measured by sonography just before and 15 to 20 minutes after diuretic injection. The Spearman test was used to assess the correlation between renal length increases due to diuretic injection and the differential renal function.
Results: The mean renal lengths ± SD measured before and after diuretic administration were 91.52 ± 20.87 and 95.38 ± 21.46 mm, respectively. The increase in renal length after diuretic administration was statistically significant (P < .001). There was a positive correlation between the renal length change and functional status (P = .006).
Conclusions: Renal length may change after diuretic injection according to the functional status, and the sonographic measurements of these changes may be used as an alternative to other imaging methods in estimation of renal function.