Society for 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

Graphic 50549 Version 5.0