What Is a CT Coronary Angiogram (CTCA)?

Simply described, an angiogram is a picture of an artery.  To capture the image the blood needs to be replaced with x-ray dye to make it visible to x-rays.  One way of doing this is by a CT Coronary Angiogram.

A CTCA requires an intravenous drip to be inserted into a vein of the arm.  The patient is then positioned feet-first into a CT scanner, so that their chest within the scanner donut.

When the x-ray dye is injected into the vein, it passes back to the right side of the heart with the venous blood.  Once there, the blood is pumped into the lungs where the blood oxygen levels are replenished.  When it returns once again to the heart it is on the left side, ready to be pumped out into the arteries to deliver the new oxygen.  When it is delivered out into the aortic artery the CT scanner takes a digital x-ray movie.

The CT images can be reconstructed to review the artery wall and the hole down the middle of the vessel.  The resolution of the images is not as high as an invasive angiogram and limited by the movement of the heart if it is not slow enough.  CTCA is also limited by the presence of calcium which can block the x-rays in the way that bone does.  However, if the heart rate is low and the image quality is good, then a CTCA can be very reassuring and may be able to rule out the need for an invasive coronary angiogram.

What to do about a blocked artery?

You can read more about a Cardiac Cath, Percutaneous Coronary Intervention (PCI) and Coronary Artery Bypass Surgery (CABGS).