What is coronary angiography?
Coronary angiography is visualization of the blood vessels of the heart (coronary arteries) by injecting radiocontrast ‘dye’ into them. Conventionally this is achieved by entering these blood vessels using small tubes known as catheters, introduced through blood vessels in the wrist or groin. In addition to this ‘invasive coronary angiography’, there is also another form of coronary angiography known as CT coronary angiography.
What is CT coronary angiography?
CT coronary angiography is a less invasive form of coronary angiography which does not require introduction of a catheter into the coronary artery. It uses multi slice computerized tomography (MSCT), also known as multi detector CT (MDCT) to capture images of coronary arteries after injecting radiocontrast into the blood vessels (veins) of the forearm. It can be done as an outpatient procedure. The scanner captures images timed to contractions and relaxations of the heart triggered by an electrocardiogram (ECG). For accurate triggering to occur the heart rate has to be stable and low. This is often achieved with the help of medications which are given before the test. Three dimensional reconstructions of the coronary arteries can be obtained by this technique. All the major branches can be seen by CT coronary angiography.
What are the downsides of CT coronary angiography?
Though CT coronary angiography is less invasive and quite convenient for the subject, the details obtained are not as good as conventional coronary angiography. It is at the best a good screening test to exclude significant coronary artery disease. Once significant coronary artery disease is detected by CT coronary angiography, conventional angiography is undertaken to decide on what type of treatment – whether coronary angioplasty (removal of blocks from coronary arteries using balloons and stents) or coronary bypass surgery is needed.