VALUE OF DIURESIS RENOGRAPHY IN THE POSTNATAL-PERIOD OF ASSUMED PHYSIOLOGICAL RENAL IMMATURITY

The aim of this study was to determine if it is possible to exclude re nal obstruction using diuresis renography in the first 6 weeks of life (the period of physiological renal immaturity), thus avoiding unneces sary invasive procedures, such as the Whitaker test or surgery. Diures is renography with I-123-hippuran was performed in 27 patients aged le ss than 6 weeks and in 50 older children who acted as a reference grou p (age 6 weeks to 1 year, n = 28; age 1-10 years, n = 22). All 27 pati ents had significant dilatation of the pelvicalyceal system on ultraso nography. Renal curves were evaluated by mathematical curve characteri stics (split renal function, counts, T-max, etc.) as the visual grade of obstruction. Whole-kidney regions of interest were defined on image s summed over 30 min; renal parenchyma on images summed over 5 min. Th e renal curves of 18/27 patients indicated tracer accumulation and led to frusemide administration. Only two patients showed no significant response to frusemide and had to be further investigated by the Whitak er test. The frequency of kidneys with no response to frusemide reveal ed no significant differences in the three groups. Whole-kidney evalua tion resulted in an overestimation of obstruction in 9/150 kidneys, wh ich matches the lower correlation to the DMSA separation values for th is method of evaluation. In contrast with the literature, significant post-renal obstruction can be excluded by diuresis renography in most cases in spite of renal immaturity and can help to avoid invasive proc edures.