Contrast Use in Cardiac CTA Applications; Supplement to Applied Radiology: December 2006.
Jacobs JE.
Coronary computed tomographic angiography (CTA) is proving to be an accurate technique for the noninvasive evaluation of coronary artery disease and coronary artery anomalies. At the same time, it enables the evaluation of the cardiac chambers, myocardium, and valves. This article will review the strengths and limitations of coronary CTA, its potential applications, and the techniques used in image acquisition and contrast administration.
Coronary CTA has several important advantages: it is noninvasive, can be performed quickly, and provides both intra-and extraluminal information. Its disadvantages include radiation exposure, the need for intravenous (IV) contrast administration, and the need for beta-blockade in most patients.
An absolute contraindication to coronary CTA is the inability to tolerate IV contrast material. Relative contraindications include cardiac arrhythmias, extensive calcification of the coronary arteries, and a rapid heart rate.
Appropriate candidates for coronary CTA include the following: patients with atypical chest pain syndromes; those who are at low-to-intermediate risk for coronary artery disease with either equivocal or abnormal results from a previous nuclear scan, stress test, electrocardiogram (ECG), or echocardiogram; those with cardiovascular risk factors, such as hypercholesterolemia, hypertension, diabetes, and smoking; those with a strong family history of cardiovascular disease; those with possible coronary anomalies in need of further anatomical delineation; and those who have undergone coronary revascularization, including coronary artery bypass grafting and stenting (Figure 1). (The quality of imaging in patients with coronary stents is variable, however.)