1. What is Normal Bladder Volume on CT?

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

Purpose: It helps radiologists and urologists assess bladder volume non-invasively from CT scan measurements.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( V \) — Volume of bladder (cm³)
• \( L \) — Maximum length (cm)
• \( W \) — Maximum width (cm)
• \( H \) — Maximum height (cm)

Explanation: The formula approximates the bladder as an ellipsoid, which is the most accurate geometric model for volume estimation.

3. Importance of Bladder Volume Measurement

Details: Accurate bladder volume assessment is crucial for diagnosing urinary retention, evaluating bladder function, and planning urological procedures.

4. Using the Calculator

Tips: Enter the maximum dimensions (length, width, height) measured from axial and sagittal CT images. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this method?
A: The ellipsoid formula has about 90% accuracy compared to actual bladder volumes in most cases.

Q2: What's a normal bladder volume range?
A: Typically 300-500 cm³ when full, but can vary based on individual factors.

Q3: Can I use this for ultrasound measurements?
A: Yes, the same formula applies for ultrasound bladder volume calculations.

Q4: How should I measure the dimensions?
A: Measure the largest diameter in each orthogonal plane (axial for width, sagittal for length and height).

Q5: What about irregularly shaped bladders?
A: The formula may be less accurate for significantly deformed bladders, and alternative methods may be needed.