FIG 8. Microscopic appearance of the threads of an aneurysm liner, inserted into a pig aneurysm and harvested within 3 hours of insertion. The threads (arrows) are surrounded by fibrin, which bridges the spaces between threads and probably forms a substrate for subsequent fibrosis (Masson trichrome, original magnification approximately x400).

FIG 9. Microscopic appearance of the neck region of an aneurysm in a dog 30 days after insertion of an aneurysm liner and GDCs. The specimen was sectioned after removal of the GDCs and the resulting vacuole is in the right lower corner. Fibrous tissue surrounds the site of the coil. Sectioned threads of the liner material (arrows) are shown, overlain by a thin continuous layer of fibrous tissue, separating the liner from the luminal surface. There is a continuous layer of flattened cells lining the neck of the aneurysm. The parent arterial wall is seen at the top of this image (Masson trichrome, original magnification approximately x90).