1. What is Bladder Volume on Ultrasound?

Definition: This calculator estimates bladder volume using ultrasound measurements based on the ellipsoid formula.

Purpose: It helps medical professionals assess bladder volume non-invasively for urological evaluations and post-void residual measurements.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( V \) — Volume of bladder (cm³)
• \( L \) — Length measurement (cm)
• \( W \) — Width measurement (cm)
• \( H \) — Height measurement (cm)

Explanation: The formula approximates the bladder as an ellipsoid shape, with π/6 being the correction factor for this geometric shape.

3. Importance of Bladder Volume Measurement

Details: Accurate bladder volume assessment helps diagnose urinary retention, evaluate bladder function, and guide catheterization decisions.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this method?
A: The ellipsoid formula is about 90% accurate compared to actual bladder volumes, with slight underestimation in very full bladders.

Q2: What's a normal bladder volume?
A: Average capacity is 400-600 mL, but varies by age, gender, and individual factors.

Q3: How do I convert cm³ to mL?
A: They are equivalent (1 cm³ = 1 mL), so no conversion needed.

Q4: When is post-void residual measured?
A: Typically measured after urination to assess incomplete bladder emptying, with >100 mL often considered significant.

Q5: Are there alternative calculation methods?
A: Yes, some use different formulas (like prolate ellipsoid) or automated ultrasound measurements, but this is the most common manual method.