Coronary CT Angiography in Managing Atherosclerosis

Abstract

Invasive coronary angiography (ICA) was the only method to image coronary arteries for a long time and is still the gold-standard. Technology of noninvasive imaging by coronary computed-tomography angiography (CCTA) has experienced remarkable progress during the last two decades. It is possible to visualize atherosclerotic lesions in the vessel wall in contrast to “lumenography” performed by ICA. Coronary artery disease can be ruled out by CCTA with excellent accuracy. The degree of stenoses is, however, often overestimated which impairs specificity. Atherosclerotic lesions can be characterized as calcified, non-calcified and partially calcified. Calcified plaques are usually quantified using the Agatston-Score. Higher scores are correlated with worse cardiovascular outcome and increased risk of cardiac events. For non-calcified or partially calcified plaques different angiographic findings like positive remodelling, a large necrotic core or spotty calcification more frequently lead to myocardial infarctions. CCTA is an important tool with increasing clinical value for ruling out coronary artery disease or relevant stenoses as well as for advanced risk stratification.

Iron Oxide Nanoparticles as Imaging and Therapeutic Agents for Atherosclerosis

“…17 These are limited because early lesions tend to bulge to the outside of the artery, whereas CT and MRI image the lumen. 18 Quantification of coronary artery calcium (CAC) score by CT has been used since the 1990s with success to diagnose subclinical atherosclerosis. 19 However, CAC scores cannot identify where at-risk lesions are located or the number and size of those that are present.…”

Coronary artery calcium score and coronary computed tomography angiography for patients with asymptomatic polyvascular (non-coronary) atherosclerosis

“…(37) It has been widely demonstrated that the sensitivity of CCTA in identifying severe stenosis is very high; on the contrary, the specificity tends to be lower due to the tendency of CCTA to overestimate stenosis, especially in calcified plaques. (24) CCTA is, in fact, indicated for patients with low-to-intermediate risk of CAD because a negative result could exclude, with significant probability, the presence of CAD. Equally, in patients at high risk for CAD, CCTA is unnecessary not only because it cannot add any information to the high pretest probability of CAD, but also as it may require a subsequent coronary angiography, which is still considered to be the gold standard for the identification of coronary stenosis.…”

“…(23) In particular, the risk of developing cardiovascular events has been shown to increase significantly when the Agatston score exceeds a value of 400. (24) In our study, in accordance with standardised protocols, CACS was performed prior to coronary angiography. In fact, calcified atherosclerotic plaques can be displayed on CCTA even without the use of endovenous contrast agents.…”

“…(27) According to standardised protocols, CCTA is performed during inspiratory apnoea and an elevated heart rate can limit the spatial resolution of its image. (24) For this reason, for all patients evaluated using CCTA, examination was done with heart rate in the range of 60-65 beats per minute. All CCTA examinations were assessed by two observers with extensive training in cardiac imaging.…”

The Role of Coronary Computed Tomography Angiography and Cardiac Magnetic Resonance in STEMI Patients with Normal Coronary Angiography

“…Plaques can be classified in three groups: calcified, non-calcified, and mixed (partially calcified). 19 CCTA underestimates the size of the non-calcified plaques and overestimates the size of calcified ones. For example, a plaque that contains a high percentage of fibrosis has high attenuation on CCTA; on the other hand, necrotic areas in the myocardium are characterized by a low attenuation.…”