Role of Diuretic Renography and Ultrasonography in Pelvic Ureteric Junction Obstruction among Infants: A Prospective Interventional Study

Abstract

Introduction: Renography is a non invasive technique routinely used by clinicians to provide information about kidney structure and function. However, its role in the diagnosis of renovascular disease (especially in patients with renal insufficiency), the exclusion of obstruction, and during the follow-up of patients undergoing pyeloplasty is still controversial. Aim: To study the changes in Anteroposterior Pelvic Diameter (APD), cortical thickness, split renal function and T½ post pyeloplasty at three months and to determine the usefulness of these parameters in assessing successful pyeloplasty for Pelvic Ureteric Junction Obstruction (PUJO). Materials and Methods: This prospective non randomised interventional study was conducted in the Department of Nuclear Medicine, PGIMER, Chandigarh, India and Department of Paediatrics, JIPMER, Karaikal, Puducherry, India, from July 2020 to July 2021. A total of 31 infants with persistent postnatal Hydronephrosis (HDN) on Ultrasonography (USG) with no vesicoureteral reflux were included in the study and underwent 99mTc EC renography. The diagnosis of obstruction was determined by visual interpretation, renogram curves, Time to peak (Tmax), and Time from Tmax to T½max parameters. Patients with obstructed patterns in 99mTc EC renography underwent Anderson Hyne’s dismembered pyeloplasty. After three months of surgery, 99mTc EC renography and USG were performed on all enrolled patients. The Chi-square test was used for the comparison of the difference in proportion, and the Student’s t-test was used for the comparison of the mean difference, between two groups. Results: The mean age of enrolled infants was 5.79±3.36 months with a male preponderance (27 males and 4 females). Out of 31 infants, 23 (74%) showed an obstructive pattern of drainage on diuretic renogram and underwent Anderson-Hynes dismembered pyeloplasty. The observed difference in the preoperative renal USG anteroposterior diameter (27.85±14.3 mm) and parenchymal thickness (9.6±3.3 mm) vs postoperative anteroposterior diameter (8±3.19 mm) and parenchymal thickness (15.5±4.19 mm) was statistically significant (p-value=0.001). The follow-up renogram scan conducted at three months showed a significant reduction in clearance half-time (T½). However, there was no statistically significant variation in split renal function at three months after pyeloplasty. Conclusion: Both 99mTc EC renography and USG indicate the likelihood of successful pyeloplasty, and in settings with limited resources, USG may be a viable substitute for early follow-up after pyeloplasty.