title: Computer-assisted volumetric analysis compared with ABC/2 method for assessing warfarin-related intracranial hemorrhage volumes.
abstract: BACKGROUND
  Intraparenchymal hemorrhage (IPH) volume is a powerful predictor of 30-day mortality. Warfarin-related intracranial hemorrhage (ICH) has a higher mortality than ICH without anticoagulation, possibly due to continued growth after 24 h, larger average size, and extension to extraparenchymal compartments. We compared 2 methods of measuring ICH volume in patients with warfarin-related ICH.
  
  
  METHODS
  ICH volume was estimated using the ABC/2 method and a computer-assisted method (Analyze 6.0 software) applied to the initial head computed tomographic scans in a consecutive series of 8 patients with warfarin-related ICH. The 2 methods were compared for relative and absolute differences in estimated hematoma volumes.
  
  
  RESULTS
  The ABC/2 method underestimated hematoma volume in 4 of 5 patients with IPH, inaccurately calculated intraventricular hemorrhage volume in 2 patients (overestimated by 9%, underestimated by 23%), and underestimated a complex subdural hematoma in 1 patient by 24% despite use of the Gebel modification. The mean percentage difference between the Analyze and ABC/2 methods was 24% in ellipsoid hemorrhages and 28% in nonellipsoid hemorrhages (P = 0.77). The mean of the absolute difference between the 2 methods was 6.7 cm3 in ellipsoid hemorrhages and 38.0 cm3 in nonellipsoid hemorrhages (P = 0.18).
  
  
  CONCLUSIONS
  The ABC/2 method accurately and quickly estimates smaller, ellipsoid intraparenchymal hematomas but is inaccurate for larger, complex-shaped warfarin-related intraparenchymal, intraventricular, and subdural hematomas. Warfarin-related ICH mortality may be underestimated by the ABC/2 method because of larger, complex-shaped, and multicompartmental hematomas.
authors.affiliation: Department of Neurology, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, USA. freeman.william1@mayo.edu
authors.forename: William D
authors.initials: WD
authors.lastname: Freeman
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Barrett
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Bestic
authors.forename: James F
authors.initials: JF
authors.lastname: Meschia
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Broderick
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Brott
mesh_terms: D000465:Algorithms; D000925:Anticoagulants / Q000009:adverse effects*; D015331:Cohort Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D020300:Intracranial Hemorrhages / Q000139:chemically induced / Q000000981:diagnostic imaging* / Q000473:pathology*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed; D014859:Warfarin / Q000009:adverse effects*
chemical_list: D000925:Anticoagulants; D014859:Warfarin