Comparative evaluation of intravenous urography and diuretic renal scintigraphy in the diagnosis of pelvi-ureteric junction obstruction and determination of renal function in children

Objectives: To evaluate the sensitivity of intravenous urography (IVU) and diuretic renal scintigraphy (DRS) for the diagnosis of pelvi-ureteric junction obstruction (PUJO) in children.

Methods: We retrospectively reviewed the records of 51 children (40 male, 11 female) 4 weeks to 12 years of age (median 24 months) who underwent modified Anderson-Hynes pyeloplasty for PUJO. All patients who underwent abdominal ultrasonography (USG), non-ionic contrast IVU and DRS using F-0 protocol were included in the study. A diagnosis of PUJO was established using the antero-posterior diameter of the renal pelvis on USG and dilated PCS with non passage of contrast across the PUJ with delayed imaging on IVU. Renal scintigraphy was performed using 99mTc Ethylene dicysteine (EC)/ Diethylenetriaminepenta-acetic acid (DTPA) and a diagnosis of PUJO was determined by visual interpretation, renogram curves and Time to peak (Tmax) and Time from Tmax to T1/2max parameters. Mcnemar’s test was used to compare the sensitivity of IVP and DRS for the diagnosis of PUJO.

Results: Of the 51 patients, USG and IVU were indicative of PUJO in 31 and 30 cases respectively, while 42/51 patients showed obstructed drainage (PUJO) on DRS. Preoperative diagnosis of PUJO using all the imaging modalities showed unilateral PUJO in 50 patients (41 left sided, 9 right sided) and bilateral PUJO in 1 patient. Assuming a differential renal function of 45-55% to be normal, 15 out of 52 affected kidneys showed preserved renal function, while <10%, 11-20%, 21-30%, 31-44% and supranormal function was noted in 5, 8, 7, 13 and 3 of the affected kidneys repectively. The 2 tailed P-value of 0.0190 and Odds ratio of 0.29 from the McNemar’s test showed that IVU and DRS were not significantly different with respect to each other for the diagnosis of PUJO in this group of children.

Conclusion: Although the diagnostic sensitivity of IVU and DRS were not signifcantly different in the diagnosis of PUJO when calculated in this small number of patients, renal scintigraphy can also quantify the relative renal function of the affected kidney, which may influence further management and may help to evaluate post-operative recovery. Research Support: None