PMC3291705_01
Case 1. Anteroposterior (AP) view of left vertebral artery (VA) angiogram (A) showing a peripheral aneurysm (arrow head) located on the hemispheric branch of the posterior inferior cerebellar artery (PICA) which has a low origin on the V4 (double arrowhead). Lateral view of left VA angiogram (B) demonstrating that a small cranial branch (arrow) originating from the distal V4 is directly anastomosed with the PICA. AP view of right VA angiogram (C) showing contrast filling of the aneurysm (arrowhead) through a small branch (arrow) originating on the distal V4. Reconstructed 3-dimensional rotational angiogram (D) clearly demonstrating the upper (arrows) and lower (double arrowheads) channel of double origin of the PICA and an associating aneurysm (arrowhead). Intraoperative photograph (E) showing trapping of the distal PICA (double arrowheads) harboring aneurysm (arrowhead). Follow-up right VA angiogram obtained 3 weeks after surgical trapping (F) showing a patent flow in the hemispheric branch of the left PICA (broken arrows) by collaterals and complete exclusion of the dissecting aneurysm.
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F1
CT scan. Cerebral angiography showed an irregularly shaped aneurysm (Fig. 1A, B), strongly suspicious of dissecting origin, in the distal segment of the left PICA. A right vertebral injection (Fig. 1C) also showed contrast filling in the left PICA aneurysm through the vertebrobasilar junction and a small branch arising from the most distal part of the left V4 segment suspecting a DOPICA. Reconstructed three dimensional rotational angiogram (3DRA) clearly demonstrated a fusiform aneurysm, locating after the convergence of two channels of DOPICA, on the distal PICA (Fig. 1D). During the operation, the diseased artery was pinkish-gray in color and relatively hard in consistency (Fig. 1E). The distal flow in the left PICA was sustained with collateral circulations via the anterior inferior cerebellar artery on that side and the opposite PICA, but it appeared somewhat slow on right VA angiogram (Fig. 1F).
PMC3291705_02
Case 2. Right vertebral artery (VA) angiogram (A and B) obtained at admission showing an irregular constriction and outpouching of the right VA and revealing an extracranial origin PICA. Follow-up right VA angiogram obtained 3 days after admission (C) showing growing of aneurismal dilations from which a faint vessel arises (arrows). Enlarged, oblique view, 3DRA of the right VA (D) demonstrating that a small upper branch (arrowhead) originating from the proximal aneurysm (arrow) is directly anastomosed with the PICA (open arrowhead). The anterior spinal artery (broken arrow) originating on the V4 is located just distal to the dissection. Postoperative, lateral view of right VA angiogram (E) and AP view of left VA angiogram (F) showing total occlusion of the right VA in which are detachable coils (asterisk). PICA : posterior inferior cerebellar artery, 3DRA : three dimensional rotational angiogram, AP : anteroposterior.
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F2
A cerebral angiography (Fig. 2A, B) was performed and showed an irregular constriction and outpouching of the right vertebral artery (VA), which was strongly suggestive of a dissection. Follow-up angiography (Fig. 2C) performed 3 days later showed the evolution of the dissection and enlargement of the aneurysmal dilatations. Reconstructed 3DRA clearly showed a smaller dissecting aneurysm near the vertebro-basilar junction and another larger aneurysm locating on the V4 from which a small branch was arising and converging into the very distal portion of the right PICA suspecting DOPICA (Fig. 2D). A total of eight detachable coils were inserted in order to obliterate the dissecting VA harboring two aneurysms (Fig. 2E, F).