Types of Parenchymal Changes Diagnosed on DMSA Scans of Kidneys Affected by Different Grades of Vesicoureteral Reflux

BACKGROUND: Renal parenchymal damage and scarring usually is associated with urinary tract infection (UTI), whereas the impact of vesicoureteral reflux (VUR) on the kidneys is unclear. We aimed to compare kidneys with all grades of VUR (grades Io-V) and those without VUR by using direct radionuclide cystography, voiding cystourethrography, and findings from (99m)Tc-DMSA scintigraphy (DMSA scan). MATERIAL/METHODS: The present analysis included 253 renal ureteral units (RUU) from 129 children with VUR and recurrent UTI and children with a single febrile UTI associated with abnormal ultrasonographic findings. The 6 grades of VUR (Io, I, II, III, IV, and V) and 35 RUUs without VUR were divided into 4 groups: 1. Non-dilated VUR (grades Io-II); 2. Mildly dilated VUR (grade III); 3. Dilated VUR (grades IV–V); and 4. The control group. RESULTS: DMSA scanning showed significant differences between the groups with non-dilated VUR, grade III VUR, grades IV–V VUR, and the control group in kidney width (χ(2)=30.5; P<0.001); position and shape (χ(2)=30.6; P<0.001); intensity of activity (χ(2)=38.1; P<0.001); distribution of activity (χ(2)=34.5; P<0.001); and existence of scars (χ(2)=16; P<0.001). The probability of abnormalities on DMSA scans increased with the VUR grade. However, inside the groups of dilated and non-dilated VUR we found no significant statistical differences between those characteristics. CONCLUSIONS: Our results indicate that kidneys without VUR or with non-dilated lateral VUR and dilated VUR on the contralateral side represent 2 different categories of parenchymal changes.