A heart CT scan (also called a cardiac CT) is a non-invasive imaging test that creates detailed 3D pictures of your heart and nearby blood vessels. It has become a valuable tool in diagnosing a wide range of heart conditions due to its high image quality and accuracy.
What Is a Cardiac CT Used For?
Heart CT is widely used in line with the latest recommendations from both the American and European cardiology societies. It helps assess many conditions, including:
- Coronary artery disease (narrowing of the heart’s arteries)
- Congenital heart defects (present from birth)
- Heart valve diseases
- Heart muscle problems (cardiomyopathies)
- Tumours in or around the heart
- Diseases of major blood vessels like the aorta or pulmonary arteries
There are many potential uses for heart CT, but in this guide, we’ll focus on the most common one: Coronary CT angiography (CCTA).
When Is a Coronary CT Scan Needed?
A coronary CT angiography (CCTA) helps doctors look at the blood vessels that supply the heart. It is often used to:
- Check for narrowed or blocked arteries in people with chest pain or unclear ECG results
- Evaluate patients with a low to moderate risk of coronary artery disease
- Assess the heart before surgery or certain medical procedures
- Monitor the condition of bypass grafts or stents after heart procedures
- Offer an alternative for patients who cannot do an exercise stress test
This scan provides a detailed look at your heart without the need for an invasive procedure like cardiac catheterisation.
Who Should Not Have a CT Scan?
There are some situations where a CT scan may not be suitable, including:
- Pregnancy
- Severe kidney problems
- Acute heart attack
- Small coronary stents (less than 3 mm in diameter)
- Severe allergy to contrast dye (also called anaphylaxis)
- Claustrophobia (fear of enclosed spaces)
If any of these apply to you, make sure to inform your healthcare provider beforehand.
How to Prepare for a Coronary CT Scan
Before the scan:
You’ll usually receive a letter with detailed instructions from the CT department. If you have a history of claustrophobia or allergies to contrast dye, it’s important to let the team know as soon as you receive the letter. In some cases, your doctor may prescribe medication to help with anxiety or allergic reactions.
On the day of the scan:
- Arrive at least 30 minutes early.
- The team will check your blood pressure and heart rate
- A safety questionnaire will be provided regarding pregnancy, allergies, and any medications
A contrast dye is used to help show your coronary arteries clearly. To get sharp images, your heart rate may need to be slowed down. If your heart is beating too fast or irregularly, you may be given medication (by mouth or IV) to bring it into the ideal range – usually under 70 beats per minute. You might receive beta-blockers (to slow the heart) and nitrates (to widen the arteries). These help improve image quality. However, these medications may not be safe if you have very low blood pressure or severe narrowing of the aortic valve.
During the scan:
Small sticky pads (electrodes) will be placed on your chest to monitor your heart rhythm during the scan. This allows the CT machine to take pictures in sync with your heartbeat, reducing motion blur. Most of scanners are fast with a scanning time around 10 minutes excluding preparation and with the lowest possible X-ray exposure doses.
Understanding Your Results
A. Coronary Calcification (Calcium Scoring):
Some patients will have a “calcium score” done first using a low-dose CT scan without contrast. This measures calcium build-up in the arteries. A high score (over 160) can mean an increased risk of heart problems. If the calcium score is very high, the team may decide not to give contrast dye, as heavy calcification can interfere with image quality and lead to unclear or misleading results. In that case, your doctor may recommend a different type of test instead.
B. Coronary Artery Disease:
If the scan goes ahead with contrast, the images will show whether your coronary arteries are normal, narrowed or blocked. Your doctor will receive a detailed report to help guide further treatment or investigations.
Author’s biography
Dr Ahmed Kharabish
- MSc, MD/PhD, CESR, Facharzt
- Consultant Cardiac Radiologist
- Associate Professor of Radiology
- SCMR Level III
- EACVI Congenital MRI Level III
- BSCI BSCCT Level II
Dr. Kharabish has received his Masters and MD/PhD Degree in radiology from Cairo University, Egypt in 2009 and 2016 respectively. Currently he holds the position of an associate professor of radiology (on leave), Cairo University.
In 2014, he obtained a clinical fellowship in cardiac imaging in the German Heart Centre, Munich, Germany. Later in 2017 successfully obtained the German Board of Radiology (Facharzt). He has worked as the head of the Radiology Department in Aswan Heart Centre, Egypt with Sir Prof. M. Yacoub years and also successfully led the radiology department at Liverpool Heart and Chest Hospital until December 2024. Currently he continues to work as a consultant of cardiac imaging in Liverpool Heart and Chest Centre, United Kingdom. In addition to receiving the Level III training certificate from the SCMR in 2014, he has received level III certificate of Congenital Heart Disease CMR from the European Association of Cardiovascular Imaging (2018) and Level II in cardiac CT from the British Society of Cardiovascular Imaging.
Dr. Kharabish conducted many presentations at various national and international cardiac imaging conferences as well as authored and co-authored many valuable publications in the field of cardiac imaging as well as admin and manges an educational free youtube channel in cardiovascular imaging.
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