SPECT/CT for Imaging of Coronary Artery Disease
Cardiovascular disease is responsible for approximately 33 % of all deaths in the USA [1]. Coronary artery disease (CAD) is present in 16.3 million adults. In 2008, CAD caused approximately 405,000 deaths in the USA, making it the number one killer. About
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SPECT/CT for Imaging of Coronary Artery Disease Jan Bucerius
9.1
Introduction
Cardiovascular disease is responsible for approximately 33 % of all deaths in the USA [1]. Coronary artery disease (CAD) is present in 16.3 million adults. In 2008, CAD caused approximately 405,000 deaths in the USA, making it the number one killer. About 1.2 million people will suffer a new or recurrent heart attack each year [2]. Hemodynamically significant CAD, which is defined as a coronary stenosis >50 %, causes a narrowing of the lumen in one or several coronary arteries and, consequently, an impaired maximum perfusion to the myocardium. As a consequence, myocardial ischemia or infarction may occur in the respective territory of the left ventricle of the heart. Myocardial infarction depicts an irreversible condition, whereas myocardial ischemia is a reversible process which reflects a misbalance between the demand and the supply of oxygen to the myocardium. Under healthy conditions, the coronary artery dilates in response to this misbalance, and an increased blood flow due to this vascular dilation leads to a delivery of additional oxygen. With pathological altered and narrowed vessels in the context of CAD, the response to the increased oxygen demand is limited due to the limited blood flow (classical angina) [2, 3]. As a less common cause of decreased myocardial perfusion, spasm of a coronary artery can mimic the clinical findings of CAD (Prinzmetal angina) [2, 3]. In general, the combination of two factors is usually responsible for the lack of blood supply to the myocardium: firstly, a total or near-total occlusion of a coronary J. Bucerius, MD, PhD Department of Nuclear Medicine, Maastricht University Medical Center, P. Debyelaan 25, 6229 HX Maastricht, The Netherlands Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Center, Maastricht, The Netherlands Department of Nuclear Medicine, University hospital RWTH Aachen, Aachen, Germany e-mail: [email protected] H. Ahmadzadehfar, H.-J. Biersack (eds.), Clinical Applications of SPECT-CT, DOI 10.1007/978-3-642-35283-6_9, © Springer-Verlag Berlin Heidelberg 2014
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artery as described above and, secondly, an insufficient flow through collateral vessels to meet the metabolic demands of tissue [2]. CAD usually develops over decades even though myocardial infarction can occur without any warning or signs of disease and can cause sudden death. Progression of coronary atheroma is accelerated in patients with diabetes, hypercholesterolemia, uremia, elevated homocysteine levels, and diets rich in saturated and trans fats. As already mentioned above, coronary stenosis >50 % of the lumen diameter limits the maximum blood flow through the vessel, but still may not be accompanied by symptoms. In contrast, patients with stenoses >70 % of the coronary lumen frequently depict symptoms such as dyspnea and/or chest pain during exertion. The vascular lumen must be narrowed by >90 % to decrease myocardial perfusion at rest [2].
9.2
Myocard
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