Cardiac CT (Computed Tomography) Scan


What is a Cardiac CT Scan?

A Cardiac CT is a scan of the heart and its blood vessels (coronary arteries) using a CT scanner. A CT scanner is shaped like a giant polo mint/ring doughnut, not to be confused with the MRI scanner which is more tunnel like. A CT scanner uses x-rays (radiation) to produce the scan, providing very detailed images. 

These images can detect early signs of heart disease (otherwise known as Coronary Heart Disease) well before any symptoms develop. In turn, this early detection can help doctors manage, stabilise and/or eliminate the causes, helping save lives.

What is Coronary Artery Disease?

Coronary Artery Disease is caused by artherosclerosis (hardening) of the arteries with cholesterol build-up, and calcification (calcium build up) of the coronary arteries.

The cardiac CT scan can detect the presence of calcium at a very early stage, even before any significant blockage has developed, and potentially years before a standard health screening or exercise ECG would detect the disease.

The cardiac CT

There are two stages to a Cardiac CT Scan:

Stage 1. A Calcium Score  – to detect calcium deposits within the coronary arteries.

Stage 2. A CT coronary angiogram – to demonstrate the anatomy | pathology of the coronary arteries.

Preparation for your Cardiac Scan (Calcium Score and CT Coronary Angiogram)

Before your scan, it is important that you follow these instructions:

  • Fast for at least 4 hours.
  • Sips of water may be taken.
  • No smoking for at least 2 hours.
  • No vigorous exercise for at least 4 hours.
  • Avoid tea and coffee for at least 12 hours.

Prior to the scan, your heart needs to be beating at a certain rate to ensure a proper diagnostic result. Medication may need to be given at your appointment if your heart rate is not at the required level. This will be in the form of a tablet known as a beta-blocker. A radiographer will carry out pre-scan checks which will determine this.

If you are given this medication, you are advised not to drive for 4-6 hours after your scan. Therefore, please make sure suitable arrangements have been made for your journey home, ie, public transport; taxi; lift.

What does the scan involve?

You will be asked to change into a gown, removing only the top half of your clothing. The gown will be open to the front as we need to place ECG monitoring on your chest during the scan. You will also be asked to:

  • Remove your watch and any neck jewellery. 
  • Lie on your back on the scan table with your head  on a pillow.

A cannula (drip line) will be inserted into a vein in your arm. This will be used for the injection of x-ray dye during the scan.

You will then be asked to:

  • Place your arms up by your head on the pillow.

The ECG monitoring will now be placed on your chest. This will display your heart rate throughout the scan.

Breathing instructions will be given to you during the scan and it is very important that these are followed. The instructions will be “breathe in and hold your breath” followed by “breathe away”. These instructions will be given approximately 5-6 times during the scan.

A radiographer will inform you when the injection of x-ray dye begins. You may experience a hot flush, metallic taste in your mouth, and a realistic sensation of passing urine during this time.

After the Scan

  • The ECG monitoring and cannula will be removed and you will be asked to change back into your clothes.
  • If you have had a beta-blocker you will be asked to remain in the department for approximately 20 mins for observation.
  • You may eat/drink again as normal.
  • You will be advised to drink plenty of water in the 48 hours following your scan to flush the injection of dye from your body.

The Calcium Score

For some patients, the less invasive Calcium Score alone is deemed to be sufficient for diagnosis. There is no preparation required for the Calcium Score.

During your appointment you will be asked to change into a gown, removing only the top half of your clothing. The gown will be open to the front as we need to place ECG monitoring on your chest during the scan. You will also be asked to:

  • Remove your watch and any neck jewellery.
  • Lie on your back on the scan table with your head  on a pillow.
  • Place your arms up by your head on the pillow.

The ECG monitoring will now be placed on your chest. This will display your heart rate throughout the scan.

Breathing instructions will be given to you during the scan and it is very important these are followed. The instructions will be “breathe in and hold your breath” followed by “breathe away”. These instructions will be given approximately 5-6 times during the scan.

You may leave the hospital straight after your scan and the results will be with the referring doctor within 2-3 days.

Appointments

You will require a referral letter from your GP or Consultant.

Contact Us

You can contact the Radiology Department by:

Telephone: 1800 300 200

Fax: 01 206 4368

or at:

Email: radiology@blackrock-clinic.com