Fig. 3

Radiological imaging of the tumor in the pineal region in Case 2. a, b Gadolinium-enhanced T1-weighted imaging in Case 2 shows a well-demarcated tumor in the quadrigeminal cistern, compressing the pineal gland and splenium of the corpus callosum (white asterisk) anteriorly (a, axial view, b sagittal view). The vein of Galen (white arrow) is displaced downward. c, d Preoperative ICAG shows occlusion of the vein of Galen and deep venous flow draining through the collateral venous channel into the transverse sinus (c right venous phase, d left venous phase)