2.5
cm
37.5
cm3
18.8
mL
1
0
0
2.5
cm
37.5
cm3
18.8
mL
1
0
0
The ICH Volume Calculator uses the ABC/2 method (also known as the Broderick method) to estimate the volume of intracerebral hemorrhage (ICH) from CT scan measurements. Developed by Kothari, Broderick, and colleagues in 1996, this bedside technique provides a rapid and reasonably accurate estimate of hematoma volume without requiring advanced software or volumetric analysis. The method approximates the hemorrhage as an ellipsoid and calculates its volume using three perpendicular dimensions.
Intracerebral hemorrhage accounts for approximately 10–20% of all strokes and carries the highest mortality rate of any stroke subtype, with 30-day mortality ranging from 30% to 50%. Hematoma volume is one of the strongest predictors of morbidity and mortality after ICH, making rapid volume estimation a critical component of the initial clinical assessment. The ABC/2 method has been shown to correlate well with computer-assisted volumetric measurements (r = 0.93), making it suitable for clinical decision-making.
The formula is derived from the volume of an ellipsoid (4/3 x pi x a/2 x b/2 x c/2), simplified to approximately A x B x C / 2, where A is the greatest hemorrhage diameter on the CT slice showing the largest hemorrhage, B is the greatest diameter perpendicular to A on the same slice, and C is calculated by multiplying the number of CT slices showing hemorrhage by the slice thickness. For C measurement, slices where hemorrhage covers more than 75% of the area of the largest slice are counted as full slices, and slices with less than 25% coverage are not counted.
This calculator automates the ABC/2 computation to support rapid clinical assessment in the emergency department and ICU, providing volume estimates that inform prognostication, surgical decision-making, and triage of ICH patients.
The ABC/2 method estimates intracerebral hemorrhage volume as an ellipsoid:
Volume = A × B × C / 2
Where:
For the C measurement: count each slice where hemorrhage area is >75% of the largest slice as a full slice, slices with 25–75% as half slices, and exclude slices with <25% coverage. The simplified formula assumes the hemorrhage approximates an ellipsoid, which is accurate for most supratentorial ICH.
An estimated volume of less than 30 mL is generally associated with lower mortality and better functional outcomes. Volumes of 30–60 mL carry intermediate prognosis. Volumes greater than 60 mL are associated with very high mortality (approximately 90%) and are an independent predictor of 30-day death. Hematoma volume is a key input for the ICH Score and other prognostic tools. Volume greater than 30 mL in combination with GCS ≤ 8 may influence decisions regarding surgical evacuation.
Inputs
Results
ABC/2 = 3 × 2 × 1.5 / 2 = 4.5 mL — small hemorrhage with favorable prognosis.
Inputs
Results
ABC/2 = 6 × 5 × 4 / 2 = 60 mL — large hemorrhage with high mortality risk.
The ABC/2 method is a rapid bedside technique for estimating intracerebral hemorrhage volume from CT scans by treating the hemorrhage as an ellipsoid: Volume = A × B × C / 2, where A and B are perpendicular diameters and C is the axial extent.
The ABC/2 method correlates well with computer-assisted volumetric measurements (correlation coefficient approximately 0.93). It tends to slightly overestimate irregular hemorrhages and underestimate very large ones, but is clinically sufficient for decision-making.
Hematoma volume is one of the strongest independent predictors of morbidity and mortality after intracerebral hemorrhage. It is a key component of prognostic scores like the ICH Score and influences surgical decision-making.
Volumes greater than 30 mL are associated with significantly increased mortality. Volumes greater than 60 mL carry extremely high mortality (approximately 90%) and are often considered a threshold for very poor prognosis.
C is calculated by multiplying the number of CT slices showing hemorrhage by the slice thickness. Slices with >75% hemorrhage area are counted fully; 25–75% as half; <25% are excluded.
ABC/2 works best for relatively round or elliptical hemorrhages. It is less accurate for highly irregular, multilobulated, or intraventricular hemorrhages, where computer-assisted volumetry may be preferred.
ABC/2 is primarily designed for intraparenchymal hemorrhage. Intraventricular hemorrhage has a more complex shape that does not approximate an ellipsoid well, though modified versions have been proposed.
Yes. While the role of surgery in ICH is still debated, volume is a key consideration. Hemorrhages >30 mL with clinical deterioration or >60 mL may prompt surgical evacuation in selected patients per AHA/ASA guidelines.
While the ABC/2 method was developed for CT, the same principle can be applied to MRI measurements of hemorrhage, using susceptibility-weighted or gradient echo sequences that are sensitive to blood products.
Yes. Hematoma expansion occurs in approximately 30% of ICH patients within the first 24 hours. Repeat imaging and volume estimation helps identify expansion and guide management changes.
Roboculator Team
The Roboculator Team explains calculations, planning tools, and practical formulas in clear language for real-life situations.
How helpful was this calculator?
Be the first to rate!
