How to decide when cardiac CT is appropriate
Learn about the appropriate use criteria of cardiac CT imaging.
It's important to know the appropriate use criteria when considering cardiac CT as a diagnostic measure. In this video taken from our Cardiac CT Essentials course, you'll learn about the three main categories of indications in the use of cardiac CT and how to determine whether it is appropriate for your patient.
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[00:00:00] When considering the coronary CT, it is important to be aware of the appropriate use criteria. Indications for cardiac CT can be split into three main categories: inappropriate, uncertain, and appropriate. These are have been color-coded for the purposes of this talk. Let us now look at a few of the indications for cardiac CT, using the schematic. Coronary CT angiography is a diagnostic test to determine the cause of an individual’s symptoms.
[00:00:30] It is, therefore, inappropriate to conduct a scan in a patient with no symptoms of chest pain. It is, however, appropriate to consider coronary CT angiography in a patient who is at a low to intermediate risk, based on their risk factor profile and who has stable symptoms of chest pain. Cardiac CT is not considered appropriate as an initial test to evaluate left ventricular function or as a test to evaluate ventricular function, following an acute myocardial infarction, in heart failure patients. Cardiac
[00:01:00] CT, however, is appropriate to detect coronary artery disease, in patients at a low to intermediate pretest probability of coronary artery disease, and in those patients with newly diagnosed clinical heart failure, with no prior coronary artery disease. It is not considered appropriate to perform coronary CT angiography in patients considered to be at a high risk of coronary artery disease but it is considered to be appropriate in patients at a low to intermediate risk of coronary disease. Coronary CTA is not considered to be appropriate for cardiac arrhythmias,
[00:01:30] where the etiology is unclear after the initial evaluation. Similarly, it is not an appropriate investigation to perform in patients who have new-onset atrial fibrillation or atrial fibrillation is the underlying rhythm during imaging. It remains uncertain whether coronary CT angiography is appropriate to detect coronary artery disease in other clinical scenarios such as those patients who develop non-sustained ventricular tachycardia, where after an initial evaluation, the etiology is unclear. Similarly, it is uncertain
[00:02:00] whether coronary CTA is appropriate to evaluate patients who present with syncope. Where coronary CTA is appropriate is if a patient has stable ongoing symptoms, has an equivocal stress test or whether coronary calcium score is 400 or less and one wishes to evaluate for the presence of significant obstructive disease. In terms of coronary calcium scanning and whether one should proceed to formal coronary CTA evaluation, bearing in mind, that the diagnostic activity decreases with an increase in calcium. It is uncertain whether coronary CTA is the
[00:02:30] correct thing to do in a patient with a coronary calcium score of 401 to 1,000 Agatston units. It is considered inappropriate for patients with a coronary calcium score greater than 1,000 Agatston units to perform or undergo coronary CT angiography. It is appropriate to evaluate a patient with anginal symptoms following bypass surgery to look for bypass graft patency. It is uncertain, however, whether coronary CTA is indicated for the routine evaluation of patients who have undergone bypass surgery more than five years ago. It is inappropriate to routinely evaluate grafts in well patients who have undergone bypass grafting less than five years ago.
[00:03:00] Stent evaluation can be difficult with coronary CT angiography and it is currently considered only appropriate to evaluate for stent patency where stents are greater or equal to 3 mm and are sited in the left main stem even in asymptomatic individuals. In patients with stents within the left main stem that are greater or equal to 3 mm but there are symptoms, it remains an uncertain indication.
[00:03:30] It is considered appropriate to perform cardiac CT in patients with complex congenital heart disease. In this example, we can see an example of a coarctation of the aorta. It is also considered appropriate to evaluate left ventricular function when this cannot be evaluated adequately by other means. It is also considered to be appropriate to evaluate prosthetic heart valves using cardiac CT and also to evaluate native cardiac valves. It is appropriate to evaluate the coronary veins and also to help
[00:04:00] with lead placement from CRT devices. And it is considered appropriate for cardiac CT to be used to localize the coronary artery bypass grafts and any other relevant retrosternal anatomy. It is not considered to be appropriate for cardiac CT to be used as a first line test for cardiac masses whether these represent tumor or thrombus. By using the appropriate use criteria and being aware of the evidence-based behind CT, you will be able to gain confidence from your referring physicians.