الفهرس 
PHYSICS OF 64-MDCT SCANNERSOnly 14 pages are availabe for public view
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Abstract
In western societies, CAD is one of the leading causes of death, accounting for about 20% of all deaths in Germany and 25% of all deaths in USA. About 50% of CAD patients die after an acute myocardial infarction without prior symptoms. The main risk factors to develop CAD are age, sex (men are at higher risk than women), high blood pressure, high blood lipid level, smoking, diabetes, overweight, family history, lack of exercise, and mental stress.
Diseases of the coronary arteries present as a reduction of blood supply to the heart muscle, which affects its function. (Ohnesorge et al., 2007).
Invasive coronary angiography is still considered to be the standard reference technique; however when compared with conventional angiography, noninvasive coronary angiography by MDCT has shown a fairly high degree of accuracy for the detection of significantly obstructive coronary artery lesions. (de Feyter et al., 2008).
Currently, showing that CT coronary angiography is safe, feasible, and cost-effective, and indeed, leads to a decrease in cardiac mortality and morbidity can still encourage to further improve the imaging modalities in order to make use of the beneficial results obtained. (Stanford et al., 2005).
Despite of the limitations that can encounter performing Cardiac CT imaging such as, motion artifacts resulting from arrhythmia, or variation of heart rate during imaging, or respiratory motions, the presence of severe calcification of the arterial wall, contraindications to contrast media administration & radiation exposure in pregnancy, results can still be promising. (Nieman et al., 2003).
Coronary CTA has been proposed in the non-invasive re-evaluation of stents and re-stenosis. According to published data, stents 3 mm in diameter can be well-evaluated. The accuracy for stents ≥ 3 mm or larger is 85% but it drops to as low as 26% for smaller stents for 64-slice scanners.
Better stent visualization has become possible with further improvement of the spatial resolution with 64-slice CT by implementation of thinner detector slices combined with a flying focal spot sampling technique in the z-direction. (De Santis et al., 2009).
Multislice CT (MDCT) coronary imaging has enormous potential, and in the future volumetric acquisition of the entire heart in one breath hold and one heart beat may permit comprehensive cardiac imaging with assessment of coronary lumen, wall, and left ventricular function and perfusion. (Edward et al., 2010).