Ultrasound classification of pelvicalyceal dilatation

0collecting system hardly visible, normal
Ijust renal pelvis visible, calyces not seen. pelvic diameter <7 mm, considered normal
IIaxial renal pelvis diameter <10 mm, some calyces visible but with normal forniceal and papillar shape / configuration
IIImarked dilatation of calyces and pelvis, pelvic axial width >10 mm with flattened papilla and rounded fornices, but without parenchymal narrowing
IVgross dilatation of entire collecting system and narrowing of renal parenchyma
Vextreme type IV with only thin, membrane-like residual renal parenchymal rim