Parent Vessel Occlusion for Vertebrobasilar Fusiform and Dissecting Aneurysms

Images from the case of a 71-year-old man (patient 4 in group II) with a fusiform vertebrobasilar aneurysm with mass effect on the left medulla, causing referable symptoms.

A, Initial T2-weighted MR image of the posterior fossa shows mass effect and compression of the left medulla (arrows) from the aneurysmally dilated distal left vertebral artery (arrowheads). Note the high signal intensity within the aneurysm, signifying slow disturbed flow.

B, Anteroposterior projection angiogram of the left vertebral artery.

C, Oblique projection angiogram of the left vertebral artery shows a fusiform aneurysm extending from the distal intracranial left vertebral artery into the proximal basilar artery (arrows). Contrast material refluxed into the right vertebral artery. Note that the origin of the left posterior-inferior cerebellar artery is from the proximal basilar artery (arrowhead). The patient tolerated a 30-min temporary balloon occlusion of the left vertebral artery just proximal to the vertebrobasilar junction.

D, Lateral projection angiogram of the left vertebral artery, obtained after embolization, confirms coil occlusion of the artery.

E, Follow-up MR angiogram, obtained at 24 hr, shows preservation of blood flow to the posterior fossa via the right vertebral artery with high signal intensity slow flow and/or thrombus within the distal left vertebral aneurysm (arrowhead).

F, Patient’s symptoms improved after embolization. Axial view T2-weighted MR image obtained 18 months after embolization shows thrombosis of the proximal aneurysmal sac, as evidenced by low signal intensity (arrowhead).

G, MR angiogram obtained 18 months after embolization shows thrombosis of the proximal aneurysmal sac, as evidenced by lack of flow-related enhancement (arrows). Continued flow-related enhancement can be seen in the basilar artery (arrowhead).