Imaging description

A 19-year-old boy was brought to the emergency room following a gunshot wound to the right neck. Figure 36.1a is an axial slice from a CTA at the C2/C3 level that demonstrates bullet fragments along a trajectory from the posterolateral entrance wound through the right facet joint. In addition to subcutaneous emphysema, facet fractures, and bullet fragments, there is a subtle asymmetry of the epidural venous plexus, with enhancement on the right compared to the left. Axial time of flight MRA demonstrated a filling defect (thrombus) in the right vertebral artery in the mid neck (Fig. 36.1b). A diagnosis of traumatic dissection/transection of the right vertebral artery with associated traumatic arteriovenous fistula was suggested. Interventional radiology was consulted for embolization. Figure 36.2 depicts images from the initial pre-embolization brachiocephalic arteriogram that confirm both the right vertebral artery occlusion and arteriovenous fistulae. During the course of metallic coil embolization of the traumatized arteries that fed the arteriovenous fistulae, multiple injections were made into branch arteries. Of note, the occluded right vertebral artery itself did not supply the fistulae (Fig. 36.2d.) However, injections into the right deep cervical, distal right ascending cervical artery, proximal right ascending cervical, right common carotid, right ascending pharyngeal, and right occipital arteries all showed early filling of the epidural venous plexus and each feeding branch was embolized with metallic coils.