Abstract General Information

Title

PREDICTIVE ULTRASOUND FEATURES OF VESICOURETERAL REFLUX AND KIDNEY INJURY IN CHILDREN AND ADOLESCENTS WITH NEUROGENIC BLADDER

Introduction and objective

Vesicoureteral reflux (VUR), a significant risk factor for pyelonephritis and renal scarring, is present in up to one-third of children with neurogenic bladder (NB).

To analyze the predictive ultrasound features of VUR and kidney injury in a cohort of children and adolescents with NB.

Method

A retrospective, longitudinal, observational study composed of 127 children and adolescents with NB was guided by the Standards for Reporting of Diagnostic Accuracy Studies (STARD). The dynamic ultrasound (DUS) (test to be evaluated) data were compared with voiding cystourethrography (VCUG) and renal scintigraphy 99mTcdimercaptosuccinic acid (99mTc-DMSA) (reference tests). The overall performance for predicting reflux was assessed using two continuous sonography measurements: the renal pelvis's maximum diameter (RPD) and maximum distal ureteral diameter.
The thinning of the renal parenchyma on ultrasound was used to predict renal scarring.

Results

A total of 107 patients (66 girls, mean age 9.6 [range 6.1 to 17 years]) were enrolled. Seventeen patients (15.9%) presented VUR, eight bilateral, giving a total of 25 reflux units. Eleven had mild to moderate grade (II-III) and 14 high-grade (IV-V) VUR. For overall reflux grade, the AUC was 0.624 (95% CI, = 0.553 – 0.692) for RPD and 0.630 (95% CI, 0.556 – 0.700) for distal ureteral diameter. The diagnostic performance for detecting high-grade VUR was slightly better for both US parameters. The AUC was 0.666 (95% CI, 0.596 – 0.731) for RPD and 0.691 (95% CI, 0.619 – 0.757) for distal ureteral diameter. The same cut-offs of 5 mm for RPD and 6.5 mm for distal ureteral diameter presented the best DOR to identify children with high-grade VUR. The increase of RPD during voiding showed an accuracy of 89.2% (95% CI, 84.3-93). The thinness of renal parenchyma presented an accuracy of 88.0% (95% CI, 82.5 – 92.3) for renal scarring.

Conclusion

The DUS findings showed that renal sonography and DUS measurements predict VUR and renal scarring in children and adolescents with NB with fair to good accuracy. The DUS-specific finding of increased RPD during voiding showed moderate accuracy. Thus, DUS and VCUG should be considered complementary. Renal parenchymal thinning on DUS predicts renal scarring on renal scintigraphy with moderate accuracy.