abc2_ich_volume: ABC/2 Formula for Intracerebral Hemorrhage Volume

In cliot: Clinical Indices and Outcomes Tools

ABC/2 Formula for Intracerebral Hemorrhage Volume

Description

Calculates the estimated volume of an intracerebral hemorrhage (ICH) using the ABC/2 formula. This simple geometric approximation correlates well with planimetric measurements and is widely used for prognosis and treatment stratification.

The formula assumes an ellipsoid shape: Volume = (A * B * C) / 2.

Usage

abc2_ich_volume(hemorrhage_length_cm, hemorrhage_width_cm, num_slices, slice_thickness_mm)

Arguments

hemorrhage_length_cm	Numeric. The greatest diameter of the hemorrhage on the CT slice with the largest area (A).
hemorrhage_width_cm	Numeric. The diameter perpendicular to A on the same CT slice (B).
num_slices	Numeric. The number of CT slices containing the hemorrhage. Guidelines for counting slices: - Slice with >= 75% of the largest area: Counts as 1 slice. - Slice with 25-75% of the largest area: Counts as 0.5 slices. - Slice with < 25% of the largest area: Counts as 0 slices.
slice_thickness_mm	Numeric. The thickness of each CT slice in millimeters (typically provided in the scan metadata).

Value

A list containing:

ICH_Volume_mL	The calculated hemorrhage volume in cubic centimeters (mL).
Interpretation	Prognostic note based on the 30 mL cutoff used in the ICH Score.

References

Kothari RU, Brott T, Broderick JP, et al. The ABCs of measuring intracerebral hemorrhage volumes. Stroke. 1996;27(8):1304-1305. doi:10.1161/01.str.27.8.1304

Examples

# Example 1: Large Hemorrhage
# 5cm x 4cm on largest slice, 12 slices total (all full size), 5mm thickness
# C = 12 * 0.5cm = 6cm. Volume = (5 * 4 * 6) / 2 = 60 mL
abc2_ich_volume(5, 4, 12, 5)

# Example 2: Small Hemorrhage
# 3cm x 2cm, 3 slices (5mm thick)
# C = 3 * 0.5cm = 1.5cm. Volume = (3 * 2 * 1.5) / 2 = 4.5 mL
abc2_ich_volume(3, 2, 3, 5)

cliot documentation built on Dec. 1, 2025, 1:06 a.m.