Abdominal Imaging
Live dataEllipsoid Volume
General-purpose ellipsoid volume for any lesion or organ from three orthogonal dimensions.
Most solid lesions and organs approximate an ellipsoid. Multiplying the three maximal orthogonal diameters by π/6 (≈0.52) gives a quick volume estimate without dedicated segmentation software.
📐 Formula
Volume = 0.52 × A × B × C mL (π/6)
🎯 When to Use
- Estimating the volume of any mass, cyst, node or organ from three measured diameters.
- Serial comparison of lesion volume across studies.
- When 3D segmentation is unavailable or unnecessary.
⚙️ How It Works
- Measure the three maximal orthogonal dimensions in cm.
- Volume = 0.52 × A × B × C, where 0.52 approximates π/6.
- Result is in millilitres (cm³).
📊 Interpreting the Result
- The value is an estimate of the ellipsoid volume enclosing the structure.
- Consistent measurement technique matters more than absolute accuracy for tracking change.
- Compare against structure-specific normal ranges where they exist.
⚠️ Limitations & Pitfalls
- Assumes a regular ellipsoidal shape; irregular or infiltrative structures are over- or under-estimated.
- Operator-dependent axis selection introduces measurement variability.
- True volumetry (segmentation) is preferred when precision is critical.
📚 References
- Tann M, Sandrasegaran K, Winer-Muram HT, et al. Volumetric analysis. Radiology fundamentals of ellipsoid approximation. AJR Am J Roentgenol. 2006;187(6):W615.
- Bakker J, Olree M, Kaatee R, et al. Renal volume measurements: accuracy and repeatability of US compared with that of CT. Radiology. 1999;211(3):623-628.
⚕️ For clinical decision support only. Always verify calculations and apply clinical judgment.