1. What is the Prostate Volume Calculator (Cheng method)?

Definition: This calculator estimates prostate volume using the ellipsoid formula (π/6 × L × W × H) based on ultrasound measurements.

Purpose: It helps urologists and radiologists assess prostate size for diagnostic and treatment planning purposes.

2. How Does the Calculator Work?

The calculator uses the Cheng formula:

Where:

• \( V \) — Prostate volume (cm³)
• \( L \) — Maximum longitudinal diameter (cm)
• \( W \) — Maximum transverse diameter (cm)
• \( H \) — Maximum anteroposterior diameter (cm)

Explanation: The formula approximates the prostate as an ellipsoid and calculates its volume using the three orthogonal measurements.

3. Importance of Prostate Volume Measurement

Details: Accurate prostate volume assessment is crucial for diagnosing BPH, planning surgical interventions, and calculating PSA density.

4. Using the Calculator

Tips: Enter the three orthogonal measurements (length, width, height) in centimeters from transrectal or transabdominal ultrasound. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the normal prostate volume range?
A: Typically 20-30 cm³ in young men, often enlarges with age (may exceed 100 cm³ in BPH).

Q2: How does this compare to the prolate ellipsoid formula?
A: The Cheng method (π/6) is more accurate than the prolate formula (0.52) for most prostate shapes.

Q3: When is this calculation most useful?
A: For pre-operative planning (TURP, laser), assessing BPH severity, and calculating PSA density.

Q4: What imaging modalities can provide these measurements?
A: TRUS (transrectal ultrasound), transabdominal ultrasound, or MRI.

Q5: How accurate is this estimation?
A: Within 10-15% of actual volume for most prostate shapes, though irregular shapes may require planimetry.