Role of renal cortical scintigraphy with Tc99m-DMSA in diagnosing renal scarring in patients undergoing staged reconstruction of classical urinary bladder exstrophy

Objectives: The purpose of this study was to find out incidence of renal cortical scintigraphy done with Technetium-99m (Tc-99m) dimercaptosuccinic acid III (DMSA-III), scan to diagnose cortical scarring in patients undergoing staged reconstruction of exstrophy bladder. Patients and Methods: We retrospectively reviewed 29 post operative patients who were referred to our department for Tc99m-DMSA scan to look for renal cortical scarring from January 2012 to April 2016. Tc-99m DMSA(III) scan was done in all 29 patients (58 kidneys). Tc-99m DTPA and Tc-99m L, L-EC scans were done in 9 (18 kidneys) and 2 (4 kidneys) patients respectively. Results: Out of 29 patients male comprised 69% of cases (n = 20) and female comprised 31% of cases (n = 09).The mean age of the presentation of patients with exstrophy bladder was 7.8 years. Tc-99m DMSA(III) scan was done in 29 patients (58 kidneys).Scarring was noted in 28/58 kidneys (48.27%) on Tc-99m DMSA(III) scan. Tc-99m DTPA scan was done in 9 patients (18 kidneys). In Tc-99m DTPA scan mean GFR (standardized Gates gamma camera method) was 71.91ml/min. Micturating cystouretherography(MCU) was done in 10 patients which revealed vesicoureteric reflux(VUR) in all the patients. DRCG was done in 1 patient which showed unilateral high grade VUR. Ultrasonography (USG) was done in 29 patients. Eighteen patients were found to have normal USG findings. Four patients had bilateral hydroureteronephrosis (HDUN) and one had unilateral HDUN. Three had mild hydronephrosis (HDN) and 3 had gross HDN. Conclusion: Preservation of renal function is one of the major goals of staged reconstruction of bladder exstrophy. Renal cortical scintigraphy with Tc-99m DMSA-III has become the “the gold standard” for renal cortical scarring imaging. Hence Tc-99m DMSA scan offers a significant diagnostic advantage over other diagnostic modalities to diagnose and follow up renal cortical scarring in patients with exstrophy bladder thus help in management.