Intracerebral Hemorrhage Volume (ABC/2)
Measure maximal hematoma length, width, slice thickness, and number of CT slices with hemorrhage to approximate volume.
For 5 mm slices, enter 0.5 cm.
Count slices showing hemorrhage; adjust for partial involvement (~0.5).
How to Use This Calculator
Measure diameters on CT
Use the slice with the largest hemorrhage to determine maximal length (A) and perpendicular width (B).
Count involved slices
Multiply CT slice thickness by the number of slices showing hemorrhage to obtain depth (C).
Interpret in clinical context
Combine volume with location, NIHSS score, ICH score, and patient condition to guide management.
Formula
ICH volume (mL) = (A × B × C) ÷ 2
A = maximal hemorrhage length (cm); B = maximal width perpendicular to A (cm); C = slice thickness × number of slices with hemorrhage (cm).
The formula assumes an ellipsoid shape and is most accurate for lobar hematomas without irregular morphology.
Full Description
The ABC/2 method rapidly estimates intracerebral hemorrhage volume in emergency settings. It approximates the hematoma as an ellipsoid and is widely used in the ICH score, decision-making for surgical evacuation, and enrolment in clinical trials. Accuracy decreases for irregular, multilobar, or intraventricular hemorrhage; volumetric software or planimetric methods may be required in those cases.
Frequently Asked Questions
How do I handle partial slices?
Estimate the fraction of hemorrhage involvement and count partial slices as ~0.5 when only half of the slice contains blood.
Does the method work for intraventricular hemorrhage?
ABC/2 is less reliable for IVH or irregularly shaped hemorrhage; consider volumetric analysis when precision is needed.
Can MRI measurements be used?
Yes. Apply the same approach using MRI slice thickness and counts if CT is unavailable.
How does volume influence management?
Hematoma volume informs prognosis, eligibility for surgical evacuation (e.g., >30 mL), and risk stratification tools such as the ICH score.