Thickness of the descending aortic wall: an unreliable angiographic sign for dissecting aneurysms.

A large fusiform atherosclerotic aneurysm of the aorta with a long, thick, laminated, calcified thrombus mimicked the angiographic appearance of a dissection of the descending aorta with a 20-mm wide thrombosed false channel. Therefore, an increase in the width of the aortic wall exceeding 10 mm may not be a uniformly reliable sign for dissecting aneurysms of the descending aorta.