Atherosclerosis is the underlying cause of coronary artery disease, the number one cause of death in the United States. It is a slowly progressing chronic disease in which cholesterol deposition, invasion of monocytes and smooth muscle cells, and inflammation lead to the formation of atherosclerotic plaques in the intima of the coronary artery wall that progressively thicken it. Atherosclerosis begins in young people, who remain asymptomatic for many years, but are at increased risk of having a heart attack. Myocardial infarction occurs when insufficient blood supplies the heart muscle because atherosclerotic enlargement of the coronary artery wall has narrowed its lumen by >50% or, more commonly, when the integrity of the fibrous cap of a vulnerable plaque is fractured triggering thrombosis that occludes the artery.
The present invention provides a technology that can identify atherosclerosis in coronary arteries at an early stage while an individual at high risk for cardiovascular disease is still asymptomatic so that preventive measures can be instituted. It uses MR Imaging systems that can image small-diameter vessels like coronary arteries and algorithms that use these data to calculate the thickness of the vessel wall, an early indicator of atherosclerosis. By using an inversion radiofrequency pulse triggered by a signal connected to the cardiac cycle, image resolution is not compromised by cardiac motion, so that multiple time-resolved images of an orthogonal slice of the region of interest can be obtained for more accurate results.
Unlike alternative approaches, the present technology measures an early marker of atherosclerosis in asymptomatic patients, is not invasive, and does involve exposure to ionizing radiation or contrast dyes. It should be useful in evaluating whether a therapeutic strategy is effective in the short term and in reducing long-term cardiovascular events, and in deciding whether treatment should be instituted in high-risk, asymptomatic patients.