Haemorrhage Volume Estimation

Background and Purpose

Intracerebral haemorrhage volume is an important predictor of morbidity and mortality and is an important parameter in the calculation of the Intracerebral Haemorrhage (ICH) Score 

The volume of intracerebral hemorrhage (ICH) is a powerful prognostic indicator, correlating strongly with 30-day mortality. Rapid, bedside estimation of hemorrhage volume enables clinicians to assess severity, guide triage decisions, and enrol appropriate patients into clinical trials. The ABC/2 rule offers a validated and efficient method to estimate ICH volume from CT imaging.

The ICH score was developed at the University of California, San Francisco Medical Center (UCSF), with the original study analysing 161 patients presenting with ICH to UCSF between 1997-1998

ABC/2 Formula

• A: Maximum haemorrhage diameter on the axial CT slice with largest haemorrhage
• B: Diameter 90° to A on the same slice
• C: Cranio-caudal extent of haemorrhage, either:
  • Number of slices with visible haemorrhage × slice thickness (in cm), OR
  • Direct cranio-caudal measurement (in cm) from reformatted views

ICH Volume Estimate (mL or cm³) = A × B × C ÷ 2

Clinical Utility

• Requires <1 minute to perform
• Strong correlation with computerised planimetric measurements (R² = 0.96)
• High interrater and intrarater reliability (ICC = 0.99)
• Overestimates volume slightly (mean 1.5±1.3 mL)

Prognostic Significance

• ICH volume ≥ 30 mL is a component of the ICH Score (worse prognosis)
• Volume >50–60 mL is associated with high mortality
• Useful for trial eligibility screening (e.g., STICH criteria)

Mathematical Basis

• Simplified from the ellipsoid volume formula:
  • True: (4/3)π × (A/2) × (B/2) × (C/2)
  • Approximate: ABC/2 (assumes π ≈ 3)

Limitations

• Assumes ellipsoid morphology
• Overestimates volumes in irregular or anticoagulant-related hemorrhages
• ABC/3 may be proposed for highly irregular shapes (unvalidated)

References

• Original article: The ABCs of measuring intracerebral hemorrhage volumes (1996)
• Validation: Comparison of ABC/2 estimation technique to computer-assisted planimetric analysis in warfarin-related intracerebral parenchymal hemorrhage (2006)
• Online calculator MDCalc

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References

Publications

• Kothari RU, Brott T, Broderick JP, Barsan WG, Sauerbeck LR, Zuccarello M, Khoury J. The ABCs of measuring intracerebral hemorrhage volumes. Stroke. 1996 Aug;27(8):1304-5.
• Huttner HB, Steiner T, Hartmann M, Köhrmann M, Juettler E, Mueller S, Wikner J, Meyding-Lamade U, Schramm P, Schwab S, Schellinger PD. Comparison of ABC/2 estimation technique to computer-assisted planimetric analysis in warfarin-related intracerebral parenchymal hemorrhage. Stroke. 2006 Feb;37(2):404-8.
• Hemphill JC 3rd, Bonovich DC, Besmertis L, Manley GT, Johnston SC. The ICH score: a simple, reliable grading scale for intracerebral hemorrhage. Stroke. 2001 Apr;32(4):891-7. 
• Clarke JL, Johnston SC, Farrant M, Bernstein R, Tong D, Hemphill JC 3rd. External validation of the ICH score. Neurocrit Care. 2004;1(1):53-60.
• Baharoglu MI et al; PATCH Investigators. Platelet transfusion versus standard care after acute stroke due to spontaneous cerebral haemorrhage associated with antiplatelet therapy (PATCH): a randomised, open-label, phase 3 trial. Lancet. 2016 Jun 25;387(10038):2605-2613.
• Clinical Guidelines for Acute Stroke Management – National Stroke Foundation
• Brazis PW, Masdeu JC, Biller J. Localization in Clinical Neurology. 8e 2021
• Fuller G. Neurological Examination Made Easy. 6e 2019
• O’Brien M. Aids to the Examination of the Peripheral Nervous System. 6e 2023

FOAMed

• Gibbs M. Neuroimaging Cases 004. LITFL
• Flower O. EVACUATE: ICH Management. LITFL
• Coni R. Neuro 101: Cerebral Hemispheres. LITFL