The Evaluation of Dual-Energy Myocardial Perfusion Imaging for the Detection of Acute Myocardial Infarction by Using the Second Generation Dual-Source CT in a Porcine Model

Cardiac computed tomography (CT) has been shown a non-invasive tool with high diagnostic accuracy for the detection of coronary arterial stenosis [1]. However, the hemodynamic significance of many lesions is uncertain by Cardiac CT. Furthermore, the presence of calcified atherosclerotic plaque reduces the ability to differentiate significant stenosis from non-obstructive plaque. Thus, invasive angiography or perfusion imaging by single photon emission computed tomography (SPECT), positron emission tomography, or magnetic resonance imaging (MRI) are often better suited for accurately identifying obstructive or physiologically significant disease in these patients. Despite SPECT and PET can quantitatively determine myocardial blood flow (MBF) and coronary flow reserve, they often require high radiation dose exposure (9~11 mSv) and cannot evaluate coronary stenosis and cardiac structure due to its poor spatial resolution [1]. Although MRI requires no radiation and is accurate in identifying myocardial infarction [2], the technique requires longer time, and poses a problem in patients with pacemaker or defibrillator [3]. Extensive data regarding the prognostic value of myocardial perfusion imaging (MPI) have shown that the amount of infarcted and ischemic burden correlates with long-term outcomes and can help decide which patients are best suited for revascularization versus medical therapy. It follows that the ability to combine anatomical data from CT angiography together with the physiological significance provided by perfusion may be beneficial [4]. Dual-source CT (Dual Source Computed Tomography, DSCT) has two sets of X-ray tube as well as two sets of detectors, which allows dual energy CT (DECT) imaging and can differentiate different tissues or organs in the body according to the different intravascular iodine spectrum signals by various levels of X-ray penetration [5]. Different attenuation of different materials found inside the human body due to chemical composition and hence different kV settings (high and low); physical density of tissues and matter (how much of a certain material is there). For iodine, it is very specific dual-energy behavior, hence very well suited for DECT. This feature of DSCT provides