Objective: The aim of this study was to estimate interobserver reproducibility of Tc-99m mercaptoacetyltriglycine renography in children and adults by assessing the parameters of the International Atomic Energy Agency (IAEA) software for the analysis of dynamic renal studies.
Methods: The renograms of 65 children and 65 adults covered a wide age range, different quality of drainage, overall function and differential renal function (DRF). Three observers were processing parameters of the IAEA software. Normalized residual activity at 20 min (NORA20), NORA on the postmicturition acquisition (NORApm), PM to maximum renal count ratio (PM/max), output efficiency at 20 min (OE20), OE 20 min after diuretic stimulation (OEF + 20), whole kidney mean transit time (MTT) and DRF by integral and Rutland-Patlak were calculated by observers.
Results: The overall agreement between three observers was almost perfect [the average intraclass correlation coefficient (ICC) above 0.99] in children and adults, with no significant difference between the parameters of renal drainage, transit and DRF. ICCs for all parameters were higher than 0.980 in children under 12 months, even slightly greater for PM/max and OEF+20. In children with poor/incomplete drainage and DRF below 40%, ICCs were above 0.98. In the subgroup of adults with impaired overall tubular extraction rate, level of reproducibility was almost perfect. Slightly lower but still insignificant values of ICC were presented in adults with poor/incomplete drainage.
Conclusion: Our results indicate an excellent interobserver reproducibility for all quantitative parameters of IAEA software in both pediatric and adult patients.