FIG 1.

Measurement strategy for determining the diameter of components of dural venous sinuses. A, The maximal diameter of torcula is obtained. Superior sagittal sinus (B) and bilateral transverse sinuses (C) are measured (red line) 1 cm away from the center of the torcula (yellow line). D, The maximal diameter of the internal jugular vein is measured at the skull base. E, The maximal diameter of the vein of Galen is obtained. F, The sigmoid sinuses are measured (red line) 1 cm distal to the transverse sigmoid junction (yellow line). G, The maximal diameter of the straight sinus is obtained. JV indicates jugular vein; SS, sigmoid sinus; St. Sin., straight sinus; TS, transverse sinus; SSS, superior sagittal sinus; VOG, vein of Galen.