Neuroradiology
Demonstration dataICH Volume (ABC/2)
Rapid bedside estimate of intracerebral haemorrhage volume from three orthogonal CT measurements.
The ABC/2 method approximates an intracerebral haemorrhage as an ellipsoid, giving a fast, reproducible volume estimate on non-contrast CT without dedicated volumetry software.
🧮 Interactive Calculator
📐 Formula
Volume (mL) = (A × B × C) / 2
When to Use
- Acute spontaneous intracerebral haemorrhage on non-contrast CT.
- When a quick prognostic volume is needed at the point of care.
- Serial scans to track haematoma expansion.
How It Works
- A is the largest diameter of the haemorrhage on the CT slice with the largest clot area.
- B is the diameter perpendicular to A on that same slice.
- C is the approximate vertical dimension: count the CT slices on which haemorrhage is seen (weighted for partial slices) and multiply by slice thickness.
- Volume of the assumed ellipsoid is A × B × C / 2 in millilitres (all inputs in cm).
Interpreting the Result
- Supratentorial haematoma > 30 mL is associated with worse functional outcome and higher mortality.
- Volume > 60 mL with GCS < 9 predicts ~90% 30-day mortality.
- The method overestimates volumes for irregular or non-ellipsoid clots; a shape-correction factor (dividing by 3 instead of 2) improves accuracy for those.
Limitations & Pitfalls
- Assumes an ellipsoidal shape; less accurate for irregular, multilobulated or evacuated clots.
- Operator-dependent slice counting introduces variability, especially with thick slices.
- Not validated for subdural or epidural collections.
References
- Kothari RU, Brott T, Broderick JP, et al. The ABCs of measuring intracerebral hemorrhage volumes. Stroke. 1996;27(8):1304-1305.
- Broderick JP, Brott TG, Duldner JE, et al. Volume of intracerebral hemorrhage: a powerful and easy-to-use predictor of 30-day mortality. Stroke. 1993;24(7):987-993.
⚕️ For clinical decision support only. Always verify calculations and apply clinical judgment.