CT angiography is a safe and non-invasive test that will not hurt at all. The exam will require that a contrast agent be given intravenously that will make the blood
vessels and tissues more visable. ECG leads are used
to precisely time the image acquisition to the specific
interval in the heartbeat whene there is the least motion.
The new Brillance Cardiolvascular CT Scanner from Philips Medical Systems features advanced technology that produces split-second high quality images. All CT scanners use X-rays, however the new Brillance scanner uses a significantly lower amount of X-ray energy than many of the other CT systems on the market. 

  A CT scan produces a cross-sectional image of the human anatomy which helps the clinician rule out or confirm the presence of certain diseases. During the scan, the patient is placed on a table and moved incrementally through the squared off donut-shaped scanner while an X-ray beam is projected through cross sections of their anatomy. The X-ray energy passes through the patient and is recorded on electronic detectors in the scanner. This information is then sent to a specialized computer that reconstructs the information into individual slices and combines them sequentially into a comprensive image of the entire area scanned. The thinner the slices, the more revealing the detail in in the resulting images, and the more definitive the exam results.