FIG 3. Swine aneurysms, 1 week (A) and 12 weeks (B) postembolization.

A, Photomicrograph shows the unorganized thrombus without endothelial cell infiltration across the entire neck (H&E; original magnification, 40x).

B, Photomicrograph reveals substantial, chronic inflammatory changes in the dome, and a thick layer of hypercellular tissue across the aneurysm’s neck (H&E; original magnification, 20x). Excellent tissue preservation is achieved in both early and late time samples.