TC-99(M)-N,N-ETHYLENEDICYSTEINE SCINTIGRAPHY IN CHILDREN WITH VARIOUSRENAL DISORDERS - A COMPARATIVE-STUDY WITH TC-99(M)-MAG3

We evaluated the clinical usefulness of Tc-99(m)-N,N-ethylenedicystein e (Tc-99(m)-EC), a new renal tubular agent, in normal children and in children with various renal disorders and compared it with Tc-99(m)-me rcaptoacetyltriglycine (Tc-99(m)-MAG3). In a first group of children ( Group 1), which included 15 patients and 4 normal children, both Tc-99 (m)-EC and Tc-99(m)-MAG3 renal scintigraphy were performed within a pe riod of 1-5 days. In a second group (Group 2), consisting of 12 patien ts, only Tc-99(m)-EC scintigraphy was performed. In the normal childre n, renograms, differential renal function (DRF) ratios and semi-quanti tative parameters of the two agents were similar. For Tc-99(m)-EC and Tc-99(m)-MAG3, the mean (+/- s.D.) time to peak activity (T-max) value s were 3.2 +/- 0.5 and 3.1 +/- 0.4 min respectively, and the mean time from peak activity to 50% activity (T-1/2) values were 6.3 +/- 0.5 an d 6.4 +/- 0.4 min respectively. The mean parenchymal transit time inde x (PTTI) and mean whole-kidney transit time index (WKTTI) for Tc-99(m) -EC were 1.7 +/- 0.3 and 2.8 +/- 0.4 respectively, and for Tc-99(m)-MA G3 they were 1.8 +/- 0.2 and 3.0 +/- 0.3 min respectively. There were also no significant differences between these parameters for the two a gents in children with various renal disorders, and the correlation co efficients (r) for DRF, T-max, T-1/2, PTTI and WKTTI were 0.99, 0.98, 0.94, 0.77 and 0.63 respectively. We conclude that Tc-99(m)-EC has exc ellent imaging characteristics in children, and even has some advantag es over Tc-99(m)-MAG3. We suggest this agent can be used routinely wit h children.