Children with vesicoureteral reflux usually present with a urinary tract infection (UTI), although some cases are diagnosed during the evaluation of prenatally detected hydronephrosis. Approximately 25% of children with a UTI will be found to have reflux. Ultrasound is normal in 75% of children with reflux, and so children with a significant UTI are evaluated with a voiding cystourethrogram (VCUG). Reflux is graded based on the appearance of the VCUG: Reflux into the ureter only Reflux into the kidney with no distortion of the collecting system Reflux into the kidney with blunting of the calyceal angles and/or mild ureterectasis Reflux into the kidney with hydrouretronephrosis Reflux into the kidney with marked hydroureternephrosis and ureteral tortuosity These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.