CARDIOVASCULAR DISEASES Risk factors, genetic predisposition, and environmental factors all affect the arteries in starting up atherosclerotic processes (Atherogenesis). Atherosclerosis represents the main cause of death or early disability in developed and emerging nations, with a progressive increase in the latter. In races other than Caucasian, the risk of Atherosclerosis begins earlier and in a more serious manner. Among these races, the groups most affected are low-income populations.   Fig.1. Atherosclerosis : pathological changes of the artery vessel   In humans, the atherosclerotic process generally takes many years and even decades. The forming of the atherosclerotic plaque is a complex process that leads to the progressive reduction of the lumen of the arteries. If the process occurs in a gradual manner certain symptoms such as exertion angina and intermittent claudication will appear slowly and can easily re-occur. Although Atherosclerosis is a systemic pathology, involving the entire cardiovascular district, it attacks certain organs more frequently. When Atherosclerosis of the coronary arteries provokes coronary stenosis and occlusion this causes myocardial infarction and angina pectoris.   Fig.2. The heart: Main coronary artery vessels     Fig.3. The brain: Main artery vessels     Fig.4. The heart: Normal coronary arteries and veins Fig.5. Myocardial infarction: occlusion of the left anterior descending coronary artery When Atherosclerosis of the arteries of the central nervous system causes carotid stenosis and vascular thrombosis, this provokes an ischemic ictus or stroke. Ruptured cerebral aneurysms that are congenital, or based on Atherosclerosis, are the cause of brain haemorrhages.   Fig.6 Ischemic ictus: occlusion of the right distal anterior cerebral artery Fig.7. Brain haemorrhage : rupture of the right distal anterior cerebral artery   Atherosclerosis of the renal arteries leads to renal failure, and renal infarction, while Atherosclerosis of the splacnic circulation will provoke mesenteric ischemia or intestinal infarction. When peripheral circulation is involved, this leads to limb ischemia that will cause intermittent claudication, ulcers and gangrene of the limbs. These events can occur very dramatically as a result of the sudden rupture of the atherosclerotic plaque and the occlusion of the relative artery vessel, with acute blocking of the circulation leading to sudden death.   Atherosclerotic events do not always cause artery stenosis or occlusive lesions. Ectasia (dilatation) and aneurisms are more frequently observed affecting the aorta, but other artery vessels can be affected, such as coronary, cerebral and peripheral arteries. Gli aneurismi frequentemente sono complicati da rottura e, o da dissezione   Fig. 8. Classification system for aortic aneurysm and dissection. Red: intimal tear. Violet: dissection   Fig 9. Proximal Type II Dissecting Aortic Aneurysm. CT Angiography 3D Rendering   Fig 9. 1 Proximal Type II Dissecting Aortic Aneurysm. CT Angiography.   Fig 10 Distal Type III  Aortic Aneurysm. CT Angiography and 3D Rendering   Fig.11.Cerebral Aneurysm: main localizations