Comparison of Intracerebral Hemorrhage Volume Calculation Methods and Their Impact on Scoring Tools

Intracerebral hemorrhage (ICH) volumes are frequently used for prognostication and inclusion of patients in clinical trials. We sought to compare the original ABC/2 method and sABC/2, a simplified version with the planimetric method.

We retrospectively reviewed admission head CT scans of consecutive ICH patients admitted to a single academic center from July 2012 to April 2013. We assessed ICH volume on the admission. In ABC/2 method, A = greatest hemorrhage diameter by CT, B = diameter perpendicular to A, C = the approximate number of CT slices with hemorrhage multiplied by the slice thickness. C is weighted by area as < 25%, 25-50%, or > 75%. However, in the sABC/2 method, C is the total number of cuts with ICH without any weighting. Bland-Altman plots were generated for both the ABC/2 and sABC/2 methods in comparison to the planimetric method.

One hundred thirty-five patients with spontaneous ICH were included in the final analysis. Bland-Altman analysis illustrated that both ABC/2 and sABC/2 were concordant with the planimetric method. ABC/2 had more bias than sABC/2 (47% vs. 5%, respectively) with no evidence of a linear trend. For differentiating a volume threshold of 30 mL, ABC/2 was less sensitive but more specific than sABC/2 (P < .0001). Concordance between planimetry, ABC/2, and sABC/2 was high, evidenced by most coefficients exceeding .90.

Simplified ABC/2 (sABC/2) method performs better than ABC/2 in calculating ICH volumes. Moreover, it is better in differentiating a volume threshold of 30 mL. These findings may have implications for outcomes prediction and clinical trials inclusion.