What this calculator does
Estimates gland volume from three orthogonal dimensions and optionally calculates PSA density.
Enter length, width, height, formula preference, and PSA when available.
Clinical scope
Use this calculator to estimate prostate volume from three orthogonal dimensions on ultrasound, MRI, or CT and optionally calculate PSA density from serum PSA divided by estimated gland volume.
Applicability and exclusions
- Do not mix dimensions from different examinations, planes, or time points.
- Post-surgical anatomy, marked contour irregularity, and segmentation-based volumes may not be represented accurately by a geometric formula.
Method and calculation logic
The ellipsoid estimate multiplies width, length, and height by π/6 (approximately 0.52). PSA density is serum PSA in ng/mL divided by volume in mL. The bullet formula uses a different geometric coefficient and should be identified in the report.
Ellipsoid volume = width × length × height × π/6PSA density = serum PSA (ng/mL) / prostate volume (mL)Interpretation table
| Output | Meaning |
|---|---|
| Volume (mL) | Geometric estimate of gland volume |
| PSA density (ng/mL²) | PSA normalized to estimated volume; interpret in the full clinical pathway |
Worked example
Case: Fictional example: width 50 mm, length 40 mm, height 36 mm, PSA 6 ng/mL.
Calculation: Ellipsoid volume ≈ 50 × 40 × 36 × 0.523 / 1000 = 37.7 mL; PSA density ≈ 6/37.7 = 0.16 ng/mL².
Interpretation: Report the formula, units, and examination used; do not interpret PSA density without age, PSA trend, MRI, and clinical context.
How to use this calculator
- Complete the visible imaging and measurement fields. Required inputs are marked in the workbench.
- Review the calculated category, score, measurements, and any recommendation or warning.
- Copy the report-ready text only after checking the result against the complete examination and source guideline.
Calculator-specific questions
Why can MRI and ultrasound volumes differ?
Plane selection, caliper placement, gland shape, and the geometric approximation all introduce variability.
Is there one universal PSA-density cutoff?
No. Thresholds depend on the clinical pathway and guideline; use the calculated value with MRI findings and patient factors.
Are patient measurements sent to RadPhrases?
No. Calculator inputs and results are processed in the browser and are not submitted by this page.