Influence of Different Diuretic Renography Protocols using 99mTc-DTPA on the Split Renal Function and Equivocal Renograms in Adult Patients with Suspected Unilateral Obstructive Uropathy

Background and Purpose: To assess the influence of three different diuretic 
renography (DR) protocols using 99mTc-DTPA on the calculation of split renal 
function (SRF) compared to 99mTc-DMSA cortical scintigraphy and the 
frequency of equivocal renograms in adult patients with suspected unilateral 
obstructive uropathy. 
Methods: This prospective study enrolled patients with suspected unilateral 
obstructive uropathy, patients were divided into three groups based on the 
timing of furosemide administration: 15 minutes before (F-15, n=40), 
concurrently with (F+0, n=40), and 15 minutes after (F+15, n=42) 99mTc-DTPA 
injection. All patients underwent 99mTc-DMSA scintigraphy. Visual and 
quantitative analyses of DRs were conducted to compare SRFs obtained using 
99mTc-DTPA with those calculated by 99mTc-DMSA and to identify the number 
of equivocal renograms in each group.
Results: The study included 82 patients (45 males and 37 females, with a mean 
age of 40±12 years). A significant correlation between SRFs acquired with 
99mTc-DTPA and 99mTc-DMSA was observed in all protocols. When comparing 
the mean difference in the computed SRF between both approaches in the three 
protocols, a significant difference was detected between the F-0 and F+15 
protocols (p=0.030). Moreover, the difference was greater in the F-15/F+0 
protocols compared to the F+15 protocol on Bland–Altman analysis. The 
number of equivocal curves was significantly lower in the F-15 than the F+0 
protocol (p=0.049), yet without significant difference when compared to F+15 
(p=0.154).
Conclusion: 99mTc-DTPA dynamic scintigraphy is a simple, non- invasive and 
reliable tool for evaluating SRF. The F+15 protocol is suggested as a single 
study to evaluate SRF as well as to confirm or rule out obstruction in patients 
with suspected obstructive uropathy.