Figure 2 Quantitative measurement of radiological parameters on axial computed tomography (CT) scans(A) The midline shift on CT scans was measured as the distance from the septum pellucidum to the virtual perpendicular drawn midline (deep blue line). The maximal thickness of the hematoma was measured as the largest diameter between the brain’s surface and the inner table of the skull (green line). The boundary of the hematoma was manually traced and then calculated in each image slice and multiplied by 5 mm to assess the volume of preoperative hematoma (red line). (B) In the postoperative period, the above hematoma volume measurement method was used to estimate the volume of residual hematoma (red line) and trapped air (light blue line). (FastStone capture 9.0, FastStone Soft, USA).