CT Coronary Angiography

Overview of a CT Coronary Angiogram 

In short, a computerised tomography (CT) coronary angiogram:

• Looks at the coronary artery wall and inside the artery
• Can show narrowing and blocked arteries 
• Uses radiation, so it isn’t used as a generic test for everyone

Browse our guide on CT coronary angiographies for more information on this vital test for high-quality images.  

How a Coronary CT Angiography Works

A CT coronary angiogram is a non-invasive practice that shows your heart’s arteries in detail. Nothing is placed inside your heart or blood vessels.

What happens during the CT coronary angiogram test:

1. An iodine-based contrast dye is injected into a small vein, usually in your arm.
2. You lie on a table that slides through the doughnut-shaped CT scanner, which takes high-resolution images.
3. The dye highlights your coronary arteries, producing detailed 3D images that help doctors visualise blood flow, fatty plaques, and narrowing.

The total procedure takes around 15 minutes. Be sure to drink plenty of fluids to flush the special dye from your body.

Benefits of a CTCA include:

• Quick and painless
• Less invasive than a traditional angiogram, where the catheter (a flexible tube) is inserted through your wrist or groin 
• No recovery time is needed, meaning you can usually go home soon after

What CT Coronary Angiography Can Tell You

A CT coronary angiography is like a roadmap that helps your doctor see what’s happening inside your heart, without the need for surgery.

What a CT heart angiography shows us: 

1. Any Blocked Arteries

What we look for:

• Narrowed or blocked arteries that feed into your heart
• Where blockages are located and how serious they are

What this means for you:

• Blockages can cause chest pain or heart attacks
• Finding them early means we can treat them before problems occur
• These scans are very accurate, catching 94 out of 100 blockages

2. Your Heart Attack Risk (Calcium Score)

What we measure: A quick scan reveals calcium buildup in your arteries, a key sign of heart disease risk.

Understanding your score:

• 0 = Very low risk
• 1-99 = Mild risk, focus on prevention
• 100-299 = Moderate risk, need closer monitoring
• 300+ = Higher risk, may need treatment

Why it matters: This number helps predict your future heart health and guides treatment decisions.

3. Heart Structure Issues

We can identify:

• Holes in your heart
• Abnormal valves
• Blood vessels in unusual positions
• Congenital disabilities you may have been born with

These findings help diagnose coronary artery disease and guide any needed treatment.

4. Unusual Blood Vessel Patterns   

About 1 in 100 people have blood vessels that formed differently. We create a 3D picture to see exactly where yours are and if they could cause problems.

5. Soft Plaque (Hidden Risk)

Not all dangerous plaque is hard and calcified. We can also spot soft, fatty deposits that might rupture and cause sudden heart problems.

6. How Previous Treatments Are Working

If you’ve had heart procedures, we can evaluate if:

• Bypass grafts are still open
• Stents are working properly
• There are any new blockages

Practical Factors That May Limit the Scan

Some factors don’t make the test unsafe, but they can affect how clear the images are:

• Difficulty holding your breath for 5 seconds, which is vital for a precise scan, because even slight movements can blur the images. 
• Fast or irregular heart rhythms (such as uncontrolled atrial fibrillation)
• Heavily calcified coronary arteries, which can cause imaging “blooming”
• Obesity, especially above scanner weight or size limit

These factors do not automatically rule out CT coronary angiography. In many cases, doctors can:

• Prepare you with medication to steady your heart rate
• Use adjusted imaging settings
• Decide whether another test, such as a stress scan or invasive cardiac angiogram, is more suitable  

Your healthcare team will evaluate your history to ensure CTCA is safe and likely to offer useful results.

When to Get a CT Coronary Angiogram

Doctors follow guidelines on who should have a CT coronary angiography.

Patients With New or Suspected Angina

If you’re experiencing chest pain or symptoms that could be angina, a CT coronary angiography is now the first-line test recommended in UK guidelines.

You’ll typically be referred for a CTCA if you visit:

• Your doctor with chest discomfort
• A rapid access chest pain clinic
• A cardiologist with new, unexplained symptoms

Intermediate or Higher Heart Risk

You may benefit from CT scan coronary angiography if you:

• Are over 40
• Have several risk factors (high cholesterol, high blood pressure, diabetes, smoking, family history)
• Have concerns about your long-term heart health, even without symptoms

For these individuals, it can act as an early detection tool, offering reassurance or initiating early intervention if needed.

Low-Risk Individuals

A CT coronary angiogram is usually not needed if you’re:

• Young
• Have no risk factors
• Have a very low calculated risk of heart conditions

Lifestyle advice and routine monitoring are typically more useful.

When CTCA Isn’t Suitable

A CT coronary angiogram is safe for most people, and there are very few absolute reasons why it cannot be done. However, certain situations make the test unsuitable or require extra caution.

A CT coronary angiogram may not be appropriate in these instances:

• Pregnancy
• Severe loss of kidney function
• Iodine contrast allergy (allergic reactions like mild itching or hives, or very rarely, severe allergic-type complications)            
• Uncontrolled asthma
• Hemodynamic instability (when your blood pressure or circulation is unstable)
• Acute decompensated heart failure
• Patients on radioactive iodine therapy
• Very high-risk patients who may need immediate treatment instead

When a Private Angiogram CT Scan is Right for You

If you don’t have classic symptoms of cardiovascular disease or angina, accessing a CT angiogram through the NHS can be more difficult. The NHS requires referrals to follow strict clinical criteria. This is why many people choose a private scan for peace of mind, reassurance and proactive assessment.

At The Keyhole Heart Clinic, arranging a private evaluation is quick and straightforward. In many cases, we can help without a doctor’s referral, so you can avoid the long waits often seen in standard pathways.

We don’t just operate; we guide, support, and transform. Subscribe to our YouTube channel for regular explainers to inform and educate you on various procedures, exams and heart health tips.