Fig. 1. Type I: patent false lumen with both entry and re-entry; Type II: ‘cul-de-sac’-shaped false lumen without re-entry; Type III: thrombosed false lumen with an ulcer-like projection, which is defined as a localized blood-filled pouch protruding from the true lumen into the thrombosed false lumen; Type IV: completely thrombosed false lumen with no ulcerlike projection.