A thoracic aortic aneurysm is an aneurysm in which there is a local or multiple irreversible outward expansion or swelling of a normal vessel that exceeds 1.5 times the normal diameter for various reasons. The locations include the aortic root, ascending aorta, aortic arch, descending aorta, and thoracoabdominal aortic aneurysm that spreads to the subdiaphragm. Etiology: 1. Cystic necrosis or degenerative changes in the middle layer of the arterial wall are most common 2. Genetic disorders 3. Atherosclerosis is one of the most common 4. aortic coarctation 5. trauma 6. infections including bacteria and fungi 7. congenital is less common Prognosis: The prognosis of these diseases is generally poor. The literature reports that the average time to rupture in patients with diagnosed thoracic aortic aneurysms is only 2 years, and survival is less than 3 years. Moreover, the larger the aneurysm, the greater the chance of rupture. In addition, the natural course of aneurysms varies by etiology. Aneurysms such as Marfan syndrome, aortic coarctation, and aortic trauma are more likely to rupture and die. The 1-year and 5-year survival of patients with inoperable thoracic aortic aneurysms is 60%-70% and 13%-39%, respectively. Pathophysiology: 1, rupture of the aortic wall in the middle layer of elastic fibers degeneration, fracture or necrosis loss of elasticity resulting in local fragility, and under the impact of high-pressure blood flow in the aortic lumen, the local weakness of the artery expands outward to form an aneurysm. Most of them are single, but they can also be multiple. 2, aortic valve closure insufficiency 3, entrapment or local compression 4, thrombosis or embolism Examination: Chest X-ray: mediastinal widening Echocardiography (TTE): pericardial effusion, aortic valve closure insufficiency and entrapment endothelial piece CT angiography (CTA): obvious entrapment images are visible, which is the main basis for diagnosis MRI (MRA): similar to CT Angiography: used sparingly