Society of Fetal Urology grading system for hydronephrosis

Grade 0: no dilation (not shown). Grade 1: renal pelvis is only visualized. Grade 2: renal pelvis as well as a few, but not all, calyces are visualized. Grade 3: virtually all calyces are visualized. Grade 4: similar to Grade 3, but when compared with the normal contralateral kidney, there is parenchymal thinning.