Cardiovascular Computed Tomography (CCT)
CCT is a painless diagnostic method in which an iodinated contrast agent/dye is injected into the arm vein. As this dye circulates through the body, the image of the heart is captured in just a few beats. CCT uses x-rays to visualize the heart, great vessels, or coronary arteries. A computer then displays the information three-dimensionally to help your radiologist and physician determine if you have coronary artery disease or other abnormalities of the heart and vascular system. It can provide still images or amazing videos of the heart and valve function.
Beyond CT angiography, the technique now provides detailed assessment of the arterial wall, left ventricular and right ventricular systolic function, and cardiac valve morphology. It also enables myocardial tissue characterization and evaluation of coronary physiology with perfusion imaging. Together, these capabilities provide comprehensive evaluation of cardiac structure and function in appropriately selected patients.
New methods combining coronary CT angiography with either vasodilator stress perfusion imaging or computational fractional flow reserve (FFR) measurements may offer combined anatomic and physiologic CT assessment.
It is possible for a patient to have an allergy to an iodine-containing contrast agent used in CCT. However, even in such a case, it may still be possible to use it after appropriate premedication, a simple process called desensitization.
Among the most used clinical applications of CCT are included: coronary artery calcium scanning, coronary computed tomography angiography, evaluation of ventricular and valvular morphology and function, studies of acute aortic syndromes and pulmonary embolism, assessment of coronary blood flow and physiology, and myocardial scar evaluation.
Clinical indications for CCT encompass a broad range of potential anatomic imaging targets and clinical scenarios. These can be broadly divided into the following categories:
- Detection of coronary artery disease in symptomatic patients without known heart disease.
- Coronary artery disease risk assessment in asymptomatic patients.
- Coronary artery disease detection in other cardiac conditions.
- Use of CT angiography after other test results.
- Evaluation after revascularization.
- Evaluation of cardiac structure and function.
- evaluation of intracardiac and extracardiac structures.
Coronary CT angiography is a noninvasive method to image coronary arteries. Applications include (a) detection of in-stent stenosis, (b) evaluation of coronary bypass graft patency, and (c) detection and diagnosis of coronary artery disease. As regards the third indication, coronary CT angiography is considered most appropriate (a) in which the pretest likelihood of CAD is low or intermediate, and (b) in which the test results would contribute to improved patient management, particularly in the setting of chest pain in the emergency department without electrocardiographic changes and/or elevation of the levels of myocardial injury markers suggestive of myocardial ischemia. Coronary CT angiography is also valuable in determining anomalous origin of coronary arteries in congenital heart diseases.