ABC/2 Formula for Intracerebral Hemorrhage Volume
ABC/2 Calculator
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Predicts volume of intracranial hemorrhage from CT measurements.
Why Use
Radiologists and non-radiologists alike can estimate ICH size without the need for volumetric 3D analysis from CT or radiology software, which many non-radiologists are unfamiliar with.
When to Use
A patient has an intracranial/intracerebral hemorrhage on CT and a clinician wants a fast and accurate method to estimate its size.
Formula
Volume of Hemorrhage = A × B × C × Slices / Hemorrhage Shape A = Length B = Width C = Slice Width # Slices with Hemorrhage Present Hemorrhage Shape: If Round/Ellipsoid: 2; Otherwise: 3. (See references below for this update to the formula.) Of note, the volume of an ellipsoid is 4/3 × π × (ABC/2); when you estimate π to be ~3, the volume becomes ABC/2.
Pearls / Pitfalls
Remember to always measure accurately using the length and width of the largest area of hemorrhage.
Advice
All patients with ICH should receive neurosurgical consultation and admission to the hospital.