الفهرس 
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Abstract
Since introduction of the MSCT as a non- invasive tool for depiction of the CAD, the clinical value of coronary calcium scoring and CT coronary angiography has been subject for research work.
Several comparative studies for evaluation of MSCT angiography as a diagnostic tool for coronary artery disease using the conventional angiography as the gold standard have been published. Initial results with four-detector CT scanner were limited by motion artifacts, the presence of significant coronary calcium, the need for long breath holds, and less than optimal spatial resolution.
Improvements of the recently developed 16- and 64- channel CT scanners, including the improved spatial and temporal resolutions and considerably reduced acquisition times were reflected on the image quality leading to better results. Despite of these technical advances, the 64- slice CT coronary angiography is still sensitive to arrhythmia and limited by the severe coronary calcifications.
Challenges in evaluating the coronary arteries at CT are the small size and tortuous courses of the vessels and their continuous movements being intimately related to the cardiac chambers. Controlled heart rate and good breath holding help to reduce cardiac and respiratory motion artifacts respectively. Retrospective ECG gating and proper choice of the reconstruction window would significantly improve the examination quality.