Filling defect and dissection flap in the left V1 segment just proximal to the vertebral artery entry into the left C6 transverse foramen. Distally there is poor opacification, with no opacification of the V3 and proximal V4 segment. Contralateral opacification of the distal V4 segment from the right, with poor but some opacification of the left PICA. Basilar artery opacifies normally. No cervical spine fracture.