Non-invasive Coronary Angiography: The Role, Limitations and Future of 64-slice Spiral CT Coronary Angiography

Conventional selective X-ray coronary angiography (SCA) remains the undisputed standard of reference for the assessment of the lumen of coronary arteries. However, this is an invasive procedure with a small but not negligible health risk that needs even short hospitalization and causes patient discomfort. Among the more than 2.5 million examinations of SCA performed annually in U.S.A. and Europe, approximately 25% do not reveal essential findings and more than 40% are not followed by any kind of interventional or surgical procedure. [1] On the other hand, SCA does not provide any information concerning the coronary wall, while almost 80% of deadly myocardial infarctions are attributed to vulnerable plaques which did not cause hemodynamically severe stenoses. [2] Thus, an effort for the development of non-invasive techniques for visualization of the coronary arteries is justified. Ideally, such a technique should be capable of reliably excluding or detecting significant stenoses of the coronary lumen and, at the same time, of assessing the coronary wall and plaque structure. By means of computed tomography (CT), this goal is being accomplished with two techniques; electron beam CT (EBCT) and multislice spiral CT (MSCT).EBCT was the first CT modality capable to provide diagnostic images of the proximal and mid segments of the coronary arteries, around 199 5, but it was abandoned soon after the advent of MSCT technology. [3,4