Normal RAR < 3.5


                  PSV RA
RAR =     --------------------------
                  PSV AA


RAR - Renal Artery Ratio
PSV RA - Peak Systolic Velocity Renal Artery
PSV AA - Peak Systolic Velocity Abdominal Aorta

PSV AA should be taken:
- in a long axis of the AA,
- in the center of the AA,
- between SMA and Renal Arteries.

The Renal Arteries:
- are located approximately 1-2 cm below SMA.