CT Angio of the Coronary Arteries



CT of the coronary arteries is only possible with a multi-detector CT scanner. This new technology (currently available at 3 of our branches) makes it possible to compile an angiographic picture of the coronary arteries without the risks of an invasive procedure. An iodine-based contrast agent is injected intravenously followed by a saline injection, which allows a bolus of the contrast medium to be concentrated in the arterial system of the heart at the time of the scan.

The examination requires a high-level of skill and our staff undergoes special training to be able to scan the heart and process the images to create angiographic and 3D images of the heart and coronary vessels. 

The patient’s co-operation is critical to ensure success. The radiographer will give special breathing instructions to the patient and a breathing exercise will be performed a number of times to monitor the heart rate during a breath hold. The radiologist will inseret an intravenous line for the contrast injection. A vasodilator will be sprayed under the tongue to dilate the cardiac vessels for the scan.

Two scans will be done. The first will identify any calcium plaque in the coronary arteries. The number and size of these plaques are used to calculate the Agatston Calcium score, which quantifies the relative risk for cardiac disease.

The second scan uses the intravenous contrast agent and utilizes special technology that enables the scanner to acquire images at the same instant in every heartbeat, creating an angiographic image without movement. This is very useful to identify and diagnose the following conditions:

  • Narrowing / occlusion of the coronary arteries
  • Patency of arteries after coronary stenting
  • Electro-Anatomical Mapping prior to ablation therapy


If pathology is identified the patient will most likely be referred for an conventional cardiac angiogram. The Cardiac CT Angiogram, however, remains a non-invasive, low risk first investigation in patients at risk for cardiac disease.

Preparation for a CT of the Coronary Arteries
This examination is highly specialized and relies on the co-operation of the patient. Please ensure that you advise the receptionist and radiographer of the following conditions at the time of booking the appointment so that precautions can be taken:

  • Asthma
  • Diabetes
  • Renal disease
  • Allergies
  • Pregnancy

You will be asked to avoid any caffeine and not to smoke on the day of the scan.  When you arrive your heart rate wil be monitored with an ECG. If it is above 80bpm a beta-blocker tablet will be given, after consultation with the radiologist or cardiologist.  The heart rate is monitored again 45 minutes later and if it has slowed sufficiently the radiographer will start the scan. If your heart rate is still above 80, you might be given another tablet and will be asked to wait another 30 minutes. 

The total time spent in our department can be 1 – 2 hours. After the scan the post-processing is done with great care to ensure accuracy and the radiologist carefully reviews the images. We usually send the results to your referring doctor or you can collect it the following day. In addition to a detailed report by our specially trained radiologists, you will receive images on film and CD for reference purposes.




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