Figure 1

EOP measurement method. Panel a. shows volume rendering (VR) of the skull CT with a type 3 EOP (arrow) in a male patient from the 2019 dataset; Panel b. shows the corresponding measurement technique of the volume of the EOP, using the “Freehand V.O.I.” tool (SyngoVia). This EOP enlargement was the largest among all examinations, with a volume of 12.16 cm3.