International Reflux Study Committee classification system for vesicoureteral reflux grading: This classification system includes five grades. a, Normal ureterovesical junction. b, Grade I: reflux into non-dilated ureter. c, Grade II: reflux into the renal pelvis and calyces without dilatation. d, Grade III: mild-to-moderate dilatation of ureter and pelvicalyceal system. e, Grade IV: dilatation of the renal pelvis and calyces with moderate ureteral tortuosity and blunting of fornices. f, Grade V: gross dilatation of the ureter, pelvis and calyces with loss of papillary impressions and severe ureteral tortuosity.