SFU grading system of hydronephrosis

Last revised by Henry Knipe on 9 Jun 2024

The grading system of hydronephrosis developed by the Society of Fetal Urology (SFU) was devised to assess the degree of hydronephrosis.

This system is considered the most commonly used and was originally designed to grade neonatal and infant pelvicalyectasis ref.

  • grade 0

    • no dilatation, calyceal walls are opposed to each other

  • grade 1 (mild)

  • grade 2 (mild)

    • dilatation of the renal pelvis (mild) and calyces (pelvicalyceal pattern is retained)

    • no parenchymal atrophy

  • grade 3 (moderate)

    • moderate dilatation of the renal pelvis and calyces

    • blunting of fornices and flattening of papillae

    • mild cortical thinning may be seen

  • grade 4 (severe)

    • gross dilatation of the renal pelvis and calyces, which appear ballooned

    • loss of borders between the renal pelvis and calyces

    • renal atrophy seen as cortical thinning

All hydronephrosis grading systems are controversial in terms of their intra- and interobserver reliability 4.

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