The Cardiovascular
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Prostate Tumor Volume & Density

Ellipsoid-derived prostate/tumor volume and PSA density from ultrasound or MRI dimensions.

Prostate Tumor Volume & Density
Length (cephalocaudal)
Width (transverse)
Height (anteroposterior)
Serum PSA
ng/mL
Complete the fields above to see the result.

When to use

  • Estimating gland or tumor volume from three orthogonal ultrasound/MRI dimensions and normalizing PSA to volume.

Formula

Volume (cm3) = (pi/6) x length x width x height (prolate-ellipsoid formula, dimensions in cm). PSA density = serum PSA / volume.

Pearls and pitfalls

  • The ellipsoid formula systematically underestimates volume for irregularly shaped glands; correlate with planimetric volume when available.

References

  1. Terris MK, Stamey TA. J Urol. 1991;145(5):984-987 (ellipsoid formula for TRUS prostate volume).
  2. Benson MC, et al. J Urol. 1992;147(3 Pt 2):815-816 (PSA density concept).