Density and Shape as CT Predictors of Intracerebral Hemorrhage Growth

Abstract

Background and Purpose— Intracerebral hemorrhage (ICH) growth predicts mortality and functional outcome. We hypothesized that irregular hematoma shape and density heterogeneity, reflecting active, multifocal bleeding or a variable bleeding time course, would predict ICH growth. Methods— Three raters examined baseline sub-3-hour CT brain scans of 90 patients in the placebo arm of a Phase IIb trial of recombinant activated Factor VII in ICH. Each rater, blinded to growth data, independently applied novel 5-point categorical scales of density and shape to randomly presented baseline CT images of ICH. Density and shape were defined as either homogeneous/regular (Category 1 to 2) or heterogeneous/irregular (Category 3 to 5). Within- and between-rater reliability was determined for these scales. Growth was assessed as a continuous variable and using 3 binary definitions: (1) any ICH growth; (2) ≥33% or ≥12.5 mL ICH growth; and (3) radial growth >1 mm between baseline and 24-hour CT scan. Patients were divided into tertiles of baseline ICH volume: “small” (0 to 10 mL), “medium” (10 to 25 mL), and “large” (25 to 106 mL). Results— Inter- and intrarater agreements for the novel scales exceeded 85% (±1 category). Median growth was significantly higher in the large-volume group compared with the small group ( P <0.001) and in heterogeneous compared with homogeneous ICH ( P =0.008). Median growth trended higher in irregular ICHs compared with regular ICHs ( P =0.084). Small ICHs were more regularly shaped (43%) than medium (17%) and large (3%) ICHs ( P <0.001). Small ICHs were more homogeneous (73%) compared with medium (37%) and large (17%) ICHs ( P <0.001). Adjusting for baseline ICH volume and time to scan, density heterogeneity, but not shape irregularity, independently predicted ICH growth ( P =0.046) on a continuous growth scale. Conclusions— Large ICHs were significantly more irregular in shape, heterogeneous in density, and had greater growth. Density heterogeneity independently predicted ICH growth using some definitions.