CT Coronary Angiography (CTCA)

Previously, functional cardiac assessment such as stress echocardiography and nuclear medicine were used to indirectly assess coronary artery disease. Cardiac catheterisation and angiography is used to directly assess coronary artery disease for high risk of coronary artery disease patients. However, CTCA provides an alternative to invasive cardiac catheterisation. The test is faster (< one minute), presents less risk and discomfort for patients and has a reduced recovery time. The Medical Services Advisory Committee (MSAC) recently performed a lengthy and rigorous assessment of CTCA for safety, effectiveness and economic consideration. The result – CTCA has been proven to be the most cost-effective test for investigation of coronary artery disease, in a number of clinical circumstances. At Apex Radiology, we use the latest technology CT scanners, which produces the fast, high-resolution images needed for CTCA. Our radiologists have specialist accreditation awarded by the Conjoint Committee for the Recognition of Training in CT Coronary Angiography. In fact, Medicare has implemented a robust credentialing system to support CTCA implementation and will only rebate examinations performed and reported by radiologists accredited to perform CTCA, using a minimum 64-slice CT scanner. Specialist referred CTCA examinations performed at Apex Radiology are eligible for a Medicare rebate and are bulk-billed (for patients with a Medicare card). Apex Radiology performs CTCA at South West Health Campus and Peel Health Campus, where our staff have developed extensive technical expertise. Contraindications for CTCA consist of:

• Impaired renal function (due to IV contrast load)
• Allergy to intravenous x-ray contrast medium
• Irregular or rapid heartbeat rates – a regular, slow heart rate is required
• A CT calcium score is routinely performed prior to CTCA.

CTCA demonstrates heart anatomy and the degree of any coronary artery stenosis, which is classified as soft and/or calcified plaque. Apex Radiology radiologists are working with local cardiologists to ensure the data produced correlates with current standards of coronary catheter angiography. Interventional procedures, such as angioplasty, cannot be performed during CTCA.

As with any x-ray examination the benefit of having CTCA has to be weighed against the small potential risk of exposure to ionising radiation The Canon Genesis and Prime CTs at the SWHC and PHC are the most advanced CT scanners in WA outside of Perth for CTCA scans, achieving the lowest dose scans in 1-2 heart beat! These scanners use leading technology to reduce radiation dose to the lowest levels, whilst providing the highest quality scans.

For CTCA, it is preferred that patients have slow and regular heart beat of 65 beats per minute or less. If the heart rate at the time of scan is more than 65 bpm, the images obtained may have substantial motion artefact. Patients with a resting heart rate greater than 65 bpm need to take medication to slow the heartbeat, prior to study. You will be given a suitable beta-blocking medication if this medication is needed on the day of the scan.

If you have further questions about this medication, please contact our CT Service Manager, Tegan Wilde on 08 9729 9960 or senior radiology nurse, at our South West Campus department, on 9726 6950.

The radiographer or nurse will explain the procedure to you and give you the opportunity to ask any questions you may have. You may be asked to read and sign a consent form that gives your permission for the test. Read the form carefully and ask questions if you don’t understand.

You will be asked to remove any jewellery, or clothing with metal clips, zips or buttons as these show up on CT. You will be connected to a special heart monitor so that we can observe your heart motion during the scan.

You will lie on the CT table in a position that enables optimal visualisation of the area of interest. Patients must lie as still as possible during the entire procedure, because any movement could blur the images. You may be asked to hold your breath briefly at intervals when the images are taken. The length of the examination varies but you should expect to be with us for at least 30 minutes.

While CTCA itself is not painful, you will need an injection of a small dose of x-ray contrast through an arm vein, to enhance visualisation of the coronary arteries. You will feel a sharp prick, similar to when blood is taken. Because the contrast media shows the blood flow in organs and soft tissues, it provides further information about the problem area. However, some people might be allergic to the contrast media. After the contrast agent is injected, you may feel flushed, or experience a metallic taste in your mouth.

Please advise our staff before your CT if you:

• Have asthma
• Have had a previous allergic reaction to contrast media
• Are taking medication for Type 2 Diabetes
• Have impaired or reduced renal function

Large deposits of calcification in the coronary arteries obscure the lumen of the artery. At Apex Radiology, we perform coronary artery calcium scoring, at no additional charge, prior to CTCA to determine whether the coronary arteries are heavily calcified. The radiologist will review your CACS to ensure CTCA will be of value.

Generally, you can resume usual activities and normal diet immediately after the CTCA. One of our specially trained radiologists will interpret the CTCA and provide your doctor with a comprehensive report. You will need to return to the doctor who referred you to discuss your CTCA results. Processing and reporting of your CTCA could take up to one week. For your convenience we can generally deliver the images and report to your doctor; or you may arrange to collect the films at an alternative time, if you prefer that option.