Fig. 3

Contrast-enhanced computed tomography angiogram of the head and neck demonstrates bilateral vertebral artery dissections. A coronal reformat (left panel) and three-dimensional reconstruction (right panel), illustrate that both vertebral arteries are significantly narrowed (arrows) along a long irregular segment that extends from the C1–C2 level to the dural penetration point. The three-dimensional reformat best demonstrates the formation of multiple small pseudoaneurysms along the course of the affected segments