Non-invasive Coronary Angiography: the Role, Limitations and Future of 64-Slice Spiral Computed Tomography Coronary Angiography

Abstract

Noninvasive coronary imaging can now be accomplished with use of computed tomography coronary angiography (CTCA) which is becoming an important alternative to invasive coronary angiography in selected patients. CTCA is best applied in patients with intermediate risk for coronary artery disease (CAD). It is a reliable technique for patient screening, thus reducing the number of unnecessary invasive coronary angiography examinations, but cannot yet replace invasive coronary angiography in all patients suspected of CAD. Concerns remain regarding the radiation exposure, which is expected to be significantly reduced with the availability of improved technology and newer multi-channel scanners offering the potential to image the entire heart during a single heartbeat. The current status of CTCA is herein briefly reviewed. I N T R O D U C T I O N Conventional selective X-ray coronary angiography (CA) 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 CA 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. On the other hand, CA does not provide any information concerning the coronary wall, while almost 80% of deadly myocardial infarctions are atributed to vulnerable plaques which did not cause hemodynamically severe stenoses. 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 RevIew CT, MRI & PET/CT Department, “Hygeia” Hospital, Athens, Greece HOSPITAL CHRONICLES 2009, 4(3): 105–109 Correspondence to: Arkadios C. Roussakis, MD CT, MRI & PET/CT Department “Hygeia” Hospital Athens, Greece E-mail: arkrous@hol.gr Key wORDS: coronary angiography; computed tomography; coronary artery disease; radiation exposure; coronary