Fig. 2.

Measurement of frontal horn index (FHI), and sylvian fissure ratio (SFR). A : Frontal horn diameter (FHD), the distance between the tips of the frontal horns measured on the CT section depicting them best. B : Innner table diameter (ITD), the distance between the inner tables of the skull measured on the same section, and along the same line used to measure FHD. C1 and C2 : Maximum widths of the two sylvian fissures. D : Transpineal coronal inner table diameter. FHI was defined as the ratio of FHD to ITD (A/B). SFR was defined as the average of the maximum width of the two sylvian fissures on the section showing them at their widest, divided by the transpineal coronal inner table diameter [(C1+C2)/2D]. If the sylvian fissure was not visible in the hematoma side, the contralateral side×2 was used.