muscle layers. The main structural proteins are collagen and elastin. This causes thinning and the wall balloons allowing gross enlargement to occur, as is common in the abdominal region of the aorta. Histology The accumulation (swelling) is always in the tunica intima, between the endothelium lining and the smooth muscle middle layer of the artery wall. While the early stages, based on gross appearance, have traditionally been termed fatty streaks by pathologists, they are not composed of fat cells but of accumulations of white blood cells, especially macrophages, that have taken up oxidized low-density lipoprotein (LDL). After they accumulate large amounts of cytoplasmic membranes (with associated high cholesterol content) they are called foam cells. When foam cells die, their contents are released, which attracts more macrophages and creates an extracellular lipid core near the centre to inner surface of each atherosclerotic plaque. Conversely, the outer, older portions of the plaque become more calcified, less metabolically active and more physically stiff over time. Veins do not develop atheromata, because they are not subjected to the same haemodynamic pressure that arteries are, unless surgically moved to function as an artery, as in bypass surgery. Diagnosis Because artery walls enlarge at locations with atheroma, detecting atheroma before death and autopsy has long been problematic at best. Most methods have focused on the openings of arteries; while these methods are highly relevant, they totally miss the atheroma within the arterial lumen. Historically, arterial wall fixation, staining and thin section has been the gold standard for detection and description of atheroma, after death and autopsy. With special stains and examination, micro calcifications can be detected, typically within smooth muscle cells of the arterial media near the fatty streaks within a year or two of fatty streaks forming. Interventional and non-interventional methods to detect atherosclerosis, specifically vulnerable plaque (non-occlusive or soft plaque), are widely used in research and clinical practice today. Carotid Intima-media thickness Scan (CIMT can be measured by B-mode ultrasonography) measurement has been recommended by the American Heart Association as the most useful method to identify atherosclerosis and may now very well be the gold standard for detection. Intravascular ultrasound is the current most sensitive method detecting and measuring more advanced atheroma within living individuals, but has had limited applications due to cost and body invasiveness. CT scans using state of the art higher resolution spiral, or the higher speed EBT, machines have been