renal volume in cubic centimeters =
= (length in cm) * (thickness in cm) * (width in cm) * 0.5
renal central echogenic area volume in cubic centimeters =
= (length in cm) * (thickness in cm) * (width in cm) * 0.5
renal parenchymal volume =
= (renal volume) – (central volume)
relative volume of the central echogenic area =
= (central echogenic area volume) / (total renal volume) * 100
where:
• The factor 0.5 may vary (0.52, etc.).
Interpretation:
• The relative volume of the central echogenic area is greater for the left kidney than the right. It tends to increase with age.
Limitations:
• The more a person's kidney deviates from a pure ellipsoid the less reliable the calculations are.
• For trending the renal volume over time, accurate measurements are needed to prevent misleading interpretations of size change.
