Abstract W P330: Intracerebral Hemorrhage Volume Measurement: Modified ABC/2 Method is Faster and Reliable

Abstract

Background: Intracerebral hemorrhage (ICH) volume calculation using ABC/2 method is well established and is widely used. Modifications of the method have been proposed which can make hematoma volume measurement faster. Helical computed tomographic (CT) techniques with multiplanar reconstructions allow direct measurement of the antero-posterior (AP), transverse (TV) and craniocaudal (CC) diameters, thereby allowing calculation of the hematoma volume using a modified ABC/2 method. We investigated the reliability of the modified ABC/2 technique of ICH volume measurement. Method: Forty-one consecutive patients with ICH were identified from a 6-month period following review of the medical records. A board-certified neurologist used the established ABC/2 formula, while a board-certified neuroradiologist used the modified ABC/2 formula to calculate the ICH volumes. The neuroradiologist took the AP measurements off the axial section while TV as well as CC measurements off the coronal images. Statistical analysis was performed. Results: The neuroradiologist took significantly less time (9 ± 3seconds) in measuring the volumes as opposed to the neurologist (44 ± 12 seconds), p<0.001. The average ICH volume as measured by the neurologist (13.2 ± 16.4 cc) was significantly smaller than the neuroradiologist measured ICH volume (19 ± 32 cc), p <0.001. When hematoma volume was dichotomized with 30 cc as the cutoff, the examiners agreed on volumes of < 30 cc more often (95%) than the volumes of > 30 cc (66%). The volumes measured using the two methods were significantly correlated (r= 0.85, p<0.001) with a high inter-rater reliability (Cronbach’s alpha= 0.82, ICC= 0.8). For individual dimensions, the agreement was least for TV diameters (Cronbach’s alpha = 0.7, ICC= 0.7) and highest for AP diameters (Cronbach’s alpha = 0.95, ICC= 0.95). Conclusion: The modified ABC/2 formula can quickly and reliably measure the hematoma volume based on our findings. We plan to test reliability and validity further with a larger examiner pool before its routine clinical application is suggested.