Fig 4.

Study animal 10, 3-month implant.

A, Anteroposterior digital subtraction angiogram of the brachiocephalic artery shows a wide-necked 4-mm-wide 11-mm-high aneurysm (black arrow).

B, Anteroposterior digital subtraction angiogram obtained immediately after embolization with a single complex coil and a single hydrogel device shows dense packing of the aneurysm dome, with persistent flow at the aneurysm neck (straight white arrow).

C, Anteroposterior digital subtraction angiogram obtained 3 months after embolization shows progressive occlusion of the aneurysm cavity, with the neck now occluded (curved white arrow).

D, Hematoxylin and eosin stain; original magnification, ×6.3. Coronal section obtained through the aneurysm cavity. The sac is nearly completely filled with hydrogel, which stains as faint, violet-colored, reticular material. There is a small amount of organized tissue near the neck (arrow).