Evaluation of changes in renal parenchymal stiffness in children with vesicoureteral reflux (VUR) by shear wave elastography (SWE) using dimercaptosuccinic acid scintigraphy (DMSA) data.

Introduction: Vesicoureteral reflux (VUR) is a disease that refers to retrograde escape of urine from the bladder to the urinary collecting system. It is mostly seen in the pediatric age group. Children with VUR have an increased risk of urinary tract infections (UTIs), pyelonephritis, and kidney scarring. The aim of this study was to investigate the effect of VUR on the affected kidney in children via shear wave elastography (SWE) and to evaluate its relationship with dimercaptosuccinic acid (DMSA) data.

Materials and methods: Our study was conducted prospectively between January 2020 and May 2023, including 52 children who were diagnosed with VUR, and 54 healthy children constituted the control group. Kidneys were divided into upper pole, mid-kidney, and lower pole, and at least three SWE values in meters per second (m/sec) were obtained from each zone. For each kidney, we obtained the arithmetic mean of the three zones. We obtained DMSA scintigraphy images from the patients within a month. We compared the DMSA data and SWE values of healthy controls and children with VUR.

Results: Compared with the control group, the mean SWE values in the right and left kidneys were significantly lower in VUR patients with no scar on the DMSA (p = 0.039 for right, p = 0.00 for left). There was no significant difference between the mean SWE values in pediatric patients with scarred VUR and those in the control group (p = 0.584 for right, p = 0.184 for left). In the patient and control groups, a positive correlation was observed between age and the SWE values (for the right kidney, p < 0.001 in the patient group and control group; for the left kidney, p = 0.003 in the patient group and p = 0.001 in the control group, p < 0.05).

Discussion: In our study, the SWE values of kidneys diagnosed with VUR without a scar were significantly lower than those of the control group. There was no significant difference between the SWE values of the VUR-diagnosed kidney with scar and the control group. SWE may be a useful modality to determine whether the kidney is affected by the disease by measuring parenchymal stiffness in children with VUR without scarring.

Conclusions: SWE may help detect renal parenchymal involvement in children with VUR, especially before scar formation, and could serve as a complementary, radiation-free imaging modality to DMSA. SWE values increase with age in children.