A CT coronary angiogram is an X-ray test that creates 3 dimensional images of your heart and the arteries supplying blood to your heart – the ‘coronary arteries’. It involves the injection of contrast dye into one of your arm veins to help visualise the lumen of the arteries to see if there are any narrowings or blockages.
During a CT angiogram, you lie on a bed that passes through a the scanner - a doughnut-shaped ring. A special dye is put in a vein in your arm or hand to make the blood vessels easier to see on the scan. If your kidney function is not perfect, as is often the case as people get older, you may require intravenous fluids to hydrate you prior to the test to prevent the contrast dye causing any further impairment of kidney function.
This is a non-invasive test but it does involve a small amount of radiation; this is rarely a cause for concern but is taken into consideration before suggesting the test be undertaken. Allergic reaction to the dye occurs rarely and is treatable. The contrast dye can effect kidney function but the risk of this is reduced by prehydration (as above).
The advantage of the CT coronary angiogram is that it is a non-invasive test with minor risks only. The disadvantage is that if it suggests narrowings of the coronary arteries that are or maybe significant, then an invasive diagnostic coronary angiogram is usually required.