Table 1 Comparison of the MRU-UUTD grading system with the SFU grading system

Grade 0

① Closely apposed central renal complex;

② No ureteral dilation

No hydronephrosis

Grade 1

① Slightly separation of the central renal complex without visualized calices

② Dilated Ureter, < 7 mm in diameter

Visible renal pelvis without calices

Grade 2

① Further dilated renal pelvis, a single or a few visualized calices;

② Dilated Ureter, < 10 mm in diameter

Hydronephrosis with a single or a few visualized calices

Grade 3

① Fully dilated renal pelvis, fluid-filled calices throughout the kidney;

② Thinned renal parenchyma overlying the calices (< 50%)

③ Tortuous Ureter, < 15 mm in diameter

Hydronephrosis with fluid-filled calices throughout the kidney

Grade 4

① Fully dilated renal pelvis, fluid-filled calices throughout the kidney;

② Thinned renal parenchyma overlying the calices (> 50%)

③ Tortuous Ureter, > 15 mm in diameter

Hydronephrosis with fluid-filled calices throughout the kidney, together with thinned renal parenchyma