doiSerbia

Diagnostic performances and clinical usefulness of comprehensive non-commercial software for renogram analysis: Values of renal output efficiency and normalized residual activity in suspected kidney outflow obstruction

Beatović Slobodanka Lj. (University of Belgrade Faculty of Medicine, Clinical Center of Serbia Center for Nuclear Medicine, Belgrade, Serbia), beatovic.boba@gmail.com
Radulović Marija (Military Medical Academy, Institute of Nuclear Medicine, Belgrade, Serbia)
Durutović Otaš R. (University of Belgrade, Faculty of Medicine, Clinical Center of Serbia, Clinic for Urology, Belgrade, Serbia)
Veljković Miloš M. (Clinical Center of Serbia, Center for Nuclear Medicine, Belgrade, Serbia)
Šaponjski Jelena M. (Clinical Center of Serbia, Center for Nuclear Medicine, Belgrade, Serbia)
Artiko Vera M. (University of Belgrade Faculty of Medicine, Clinical Center of Serbia Center for Nuclear Medicine, Belgrade, Serbia)
Šobić-Šaranović Dragana P. (University of Belgrade Faculty of Medicine, Clinical Center of Serbia Center for Nuclear Medicine, Belgrade, Serbia)

Introduction/Objective. Nuclear Medicine Section of IAEA has developed the software for dynamic renal scintigraphy, which allows calculation of advanced parameters of drainage: renal output efficiency (OE) and normalized residual activity (NORA). The aim of this study was to validate IAEA software by comparing results of parameters of renal drainage in normal subjects against their established reference values and to assess diagnostic accuracy of OE and NORA in distinguishing between obstruction/unobstruction. Methods. Fifty-five patients with suspected obstruction and 36 kidney donors were investigated. Group A consisted of 24 obstructed kidneys, Group B of 37 kidneys with dilated urinary tract, and Group C of 72 normal kidneys. Forty-minute acquisition was applied. Furosemide was administered after 20 minutes. Post-micturition image was acquired at 50 minutes. The analyzed parameters were as follows: OE at 20 minutes (OE20) and at the end of the furosemide test (OE40), NORA at 20 minutes (NORA20) and after micturition (NORAPM). One-way ANOVA was used for evaluating the differences between the groups. Ability of OE40 and NORAPM to distinguish between obstruction/unobstruction was determined by ROC curve analysis. The sensitivity, specificity, area under the curve, and cut-off values were analyzed. Results. Excellent agreement of our results with established OE and NORA values was found. The difference between the groups was significant for OE20, OE40, NORA20, and NORAPM (p < 0.001). Cut-off values for obstruction were 82% and 0.11 for OE40 and NORAPM, respectively. Conclusion. IAEA software gives reliable analysis of diuretic renography and helps to better diagnose obstruction. IAEA should be encouraged to produce final version of the software and to release it online.

Keywords: Radionuclide renography, uroobstruction, output efficiency, normalized residual activity