Renal Cortical Imaging with Tc-99m DMSA in Children: an Institutional Review

Background Urinary tract infection (UTI) is one of the commonly encountered conditions in children. Dimercaptosuccinic acid (DMSA) scintigraphy is widely advocated for functional and morphological evaluation of the renal cortex including parenchymal defect. Moreover, only a small percentage of renal defects are detected by ultrasound. We aimed to examine DMSA scintigraphy of children and identify factors associated with cortical defect. Methods Patients aged <= 18 years old who underwent DMSA scintigraphy (November 18, 2019-February 2, 2023, 30 children) were included. All children received intravenous injections of Tc-99m-DMSA followed by static planar and single-photon-emission computed tomography imaging at 3 hours. Cortical findings and differential functions of the worst affected kidney were graded accordingly. Grade I has no more than two cortical defects, grade II has more than two cortical defects with normal parenchyma between the defects, while grade III is when generalized damage is noted, and grade IV is when a shrunken kidney is seen with no DMSA uptake. Normal functioning kidney is when the relative function at 45 to 55%, mildly reduced function at 40 to 44%, and substantially impaired function at 10 to 39%, while nonfunctioning is when the differential split renal function < 10%. All data were then statistically analyzed. Results Majority was female (53%). The mean age was 5.85 years. UTI episodes were 73%. Twenty-two children had congenital urinary tract anomalies. All patients with vesicoureteric refluxes (VURs) had positive defects. Scintigraphy showed abnormalities in 17 children affecting unilateral (64%) or both kidneys (36%). There were 17 children (57%) respectively in the abnormal DMSA scan findings category with normal until significant impairment of the functioning kidney category. VURs were significantly associated with abnormal scintigraphy (p<0.05). A significant association was found between abnormal DMSA scan findings and differential renal function (p<0.05). Conclusion Significant association was noted between VURs and abnormal DMSA scintigraphy, abnormal DMSA scan findings, and impaired differential renal function. Special consideration should be given to these cases.