CT coronary angiogram (Coronary CT angiography (CCTA))
A detailed CT scan that uses a small injection of dye to show whether the heart's arteries are narrowed or furred up.
✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review
In short
- A CT coronary angiogram shows whether the heart's arteries are narrowed or furred up and is recommended by NICE as a first test for many people with new chest pain.
- It is very good at ruling out significant artery disease, but less precise at judging exactly how tight a narrowing is, so a further test is sometimes needed.
- It uses X-ray radiation and an injection of dye, so it is not suitable for everyone, and incidental findings in the chest are sometimes picked up.
- What matters most is what the result will change: ask whether it will alter your treatment and what happens if it is normal, abnormal or unclear.
A plain-English summary. The detail — including risks and recovery — is below.
At a glance
A general guide. Your radiologist will give you advice for your situation.
Shows whether the coronary arteries are narrowed or furred up
It may be the wrong test if the question is about the heart's rhythm or pumping rather than the arteries, which need an ECG, a monitor or an...
You lie still and hold your breath for a few seconds at a time. When the dye goes in you may feel a warm flush and a metallic taste, which passes within...
A clear report reviewed by a radiologist or cardiologist, explained in plain language.
You lie still and hold your breath for a few seconds at a time. When the dye goes in you may feel a warm flush and...
The cannula is removed and you can usually leave once any heart-slowing medicine has worn off enough. Most people...
Drink plenty of fluids to help flush the dye through your kidneys, unless you have been told to limit fluids. Any...
A radiologist or cardiologist reviews the images and writes a report. This usually takes a little time, and...
What is a CT coronary angiogram?
A CT coronary angiogram is a detailed scan that looks at the coronary arteries, the small vessels that supply the heart muscle with blood. A small amount of dye (contrast) is injected into a vein in your arm, and a CT scanner takes pictures as it passes through your heart's arteries.
It is used mainly to find out whether chest pain or other symptoms could be caused by narrowed or furred-up arteries (coronary artery disease). NICE recommends it as a first-line test for many people with recent, unexplained chest pain. It can also measure the amount of calcium in the artery walls, which is a marker of furring-up.
The scan is very good at ruling coronary artery disease out: if the arteries look clear, it is very unlikely they are significantly narrowed. It is less precise at judging exactly how tight a narrowing is, especially where there is a lot of calcium or a stent, so a further test is sometimes needed to confirm what a narrowing means.
Unlike a standard heart ultrasound (echocardiogram), this scan is specifically about the arteries. It uses X-rays, so it involves a dose of radiation, and the dye is not suitable for everyone. Your cardiologist weighs these against what the result will tell them.
Types, options & approaches
There may be different ways to do this. The right approach depends on the clinical question and your circumstances.
CT coronary angiogram vs invasive angiogram
| Question | CT coronary angiogram | Invasive angiogram |
|---|---|---|
| How it is done | Dye into an arm vein, scan from outside | Tube fed to the heart via wrist or groin |
| Main use | Rule out or detect artery disease | Confirm and often treat narrowings |
| Can treat at the same time? | No | Sometimes (with a stent) |
| Invasiveness | Lower | Higher |
A CT scan is often the first test. An invasive angiogram is used when more detail or treatment is likely needed. Your cardiologist will advise which is right.
Preparing for your scan
- Tell the team about any kidney problems, as the dye is processed by the kidneys; a blood test may be needed first.
- Tell them about diabetes and any medicines, especially metformin, which may need pausing around the scan.
- Mention any previous reaction to X-ray dye (contrast) or any serious allergy or asthma.
- Avoid caffeine (coffee, tea, energy drinks) for several hours beforehand, as advised, because it can speed up the heart.
- Take your usual medicines unless told otherwise; you may be asked to bring a beta-blocker or have one given on the day.
- Tell the team if you are or might be pregnant, as the scan uses radiation.
- Allow extra time, as your heart rate is checked and slowed before the scan if needed.
What happens
When you arrive, your heart rate is checked. Because clear pictures need a slow, steady rhythm, you may be given a beta-blocker as a tablet or an injection to bring the rate down, and a spray or tablet under the tongue to widen the arteries. A thin tube (cannula) is placed in a vein in your arm for the dye.
You lie on the scanner couch with sticky patches on your chest to track your heartbeat. As the scan runs, the dye is injected and you may feel a warm flush and a metallic taste, which is normal and passes quickly. You will be asked to hold your breath for a few seconds at a time while the pictures are taken. The scan itself takes only minutes, though the whole visit takes longer.
The images are not usually interpreted on the spot. A radiologist or cardiologist reviews them and writes a report, and your results are normally given at a follow-up, sometimes within a few days.
Is this scan right for me?
A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.
May not be suitable if…
- It may be the wrong test if the question is about the heart's rhythm or pumping rather than the arteries, which need an ECG, a monitor or an echocardiogram.
- It may not be suitable if you have had a severe reaction to X-ray dye, or have significantly reduced kidney function, without extra precautions.
- Very heavy calcium in the arteries can make the scan hard to interpret, so a different test may be chosen.
- If symptoms suggest a heart attack or unstable chest pain, urgent assessment is needed rather than a planned scan.
Delay or rearrange if…
- You are or might be pregnant, because the scan uses radiation.
- You have an unstable or worsening chest pain pattern that needs urgent assessment first.
- Your kidney function needs checking or optimising before contrast dye is given.
- You have recently taken caffeine or a medicine that speeds the heart and cannot get a steady, slow rate for clear pictures.
Alternatives to discuss
- An invasive coronary angiogram when detailed assessment or treatment of a narrowing is likely needed.
- A functional test, such as a stress echocardiogram or a perfusion scan, to see how blood flow holds up under stress.
- A coronary calcium score alone as a simpler marker of furring-up in selected people.
- Managing risk factors and reviewing symptoms without imaging if a clinician judges the risk is low.
Before you decide
Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.
What matters most to me?
Think about symptoms, daily life, work, caring responsibilities, sport, fertility, travel, appearance and anxiety — the right choice depends on your priorities, not just the medical facts.
What are all my options?
Ask about waiting, monitoring, medicines, rehabilitation, a smaller or larger procedure, a different test, NHS referral, or a second opinion where that would help.
What would make me pause?
Active infection, pregnancy, unstable medical problems, smoking, medicines that increase bleeding, poor support at home, or feeling pressured are all reasons to slow down and get tailored advice.
What happens if I do nothing today?
For some problems, waiting is safe; for others, delay can make treatment harder. A good consultation should explain the trade-off in plain English.
Benefits
- Shows whether the coronary arteries are narrowed or furred up
- Very good at ruling out significant artery disease when the arteries look clear
- Recommended by NICE as a first test for many people with new chest pain
- Less invasive than an angiogram done through the wrist or groin
- Can measure artery calcium as a marker of furring-up and future risk
- Helps your cardiologist decide on medicines, lifestyle advice or whether further tests are needed
Risks & complications
- A warm flush, a metallic taste or a feeling of needing to pass urine when the dye is injected, which passes quickly
- Bruising or discomfort where the cannula goes into your arm
- Exposure to a dose of X-ray radiation
- Incidental findings in the chest, such as lung spots, that may need further scans or follow-up
- A mild reaction to the dye, such as itching, a rash or nausea
- A slow heart rate, tiredness or low blood pressure from the beta-blocker used to steady the heart
- A headache or flushing from the spray used to widen the arteries
- A result that is unclear, often because of heavy calcium or a stent, needing a further test
- A severe allergic reaction to the dye, which the team is trained and equipped to treat
- Kidney strain from the dye, mainly in people who already have reduced kidney function
- A narrowing that is over- or under-estimated, leading to an unnecessary or a missed further test
The main trade-offs are radiation, the dye and the medicines used to steady the heart. The radiation dose is higher than a chest X-ray; one NHS source likens it to about three years of natural background radiation. The dye can rarely cause an allergic reaction or strain the kidneys, so tell the team about allergies, asthma, kidney problems and diabetes. The scan is excellent at ruling artery disease out but less precise at grading a narrowing, and incidental findings in the chest can lead to more tests, so ask what the result will actually change for you.
Published figures to discuss
As an imaging test, the key uncertainties are about accuracy and the dye rather than a high chance of harm. Coronary CT angiography is very good at ruling out significant disease, with a high negative predictive value, but it is less precise at grading how tight a narrowing is, so false positives and unclear results occur, particularly with heavy calcium or stents. Serious dye reactions and kidney effects are uncommon and depend on individual risk factors. Incidental findings in the chest are common and vary in importance.
| Figure | Reported range | How to interpret it | Source / confidence |
|---|---|---|---|
| Ruling out significant coronary artery disease | High negative predictive value (around 99% in early studies), meaning a normal scan makes significant narrowing very unlikely | It is more reliable for ruling disease out than for grading exactly how severe a narrowing is. | Coronary CT angiography — StatPearls (NCBI)ncbi.nlm.nih.govPublished figure |
| Diagnostic accuracy for significant narrowing | Reported sensitivity around 94% and specificity around 97% in early studies | Accuracy is lower where there is heavy calcium or a stent, which can over-estimate narrowing. | Coronary CT angiography — StatPearls (NCBI)ncbi.nlm.nih.govPublished figure |
| Contrast reaction or kidney strain | Uncommon in low-risk patients; risk depends on allergy history and kidney function | A good booking process checks kidney function, previous contrast reactions, asthma/allergy history and metformin/diabetes context where relevant. | Coronary CT angiography — StatPearls (NCBI)ncbi.nlm.nih.govSource-linked context |
| Radiation exposure | Low but not zero; dose varies by scanner and protocol | The benefit is strongest when the result will change chest-pain management. It should not be used as a casual screening test. | Guide sourcesClinical context |
| Incidental non-cardiac findings | Recognised | Lung or other incidental findings can create useful diagnoses or unnecessary anxiety and follow-up imaging. | Guide sourcesClinical context |
These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.
What happens afterwards
There is usually no physical recovery and you can return to normal activity the same day. The main wait is for a radiologist or cardiologist to report the scan and for your results to be explained.
- A brief warm flush, metallic taste or urge to pass urine as the dye is injected
- Mild bruising at the cannula site in the arm
- Feeling a little tired or having a slower pulse for a while after the beta-blocker
- No immediate change in your symptoms, as this is a test rather than a treatment
- Waiting a short time for the scan to be reported before you get results
Aftercare
- Drink plenty of fluids afterwards to help your kidneys clear the dye, unless told otherwise.
- Do not drive for the rest of the day if you were given a sedative; otherwise normal activity is usually fine.
- Restart any medicine, such as metformin, only when the team tells you it is safe.
- Keep an eye on the cannula site and press on it if there is any minor bleeding or bruising.
- Watch for any delayed dye reaction, such as a rash or itching, in the hours after the scan.
- Make sure you know how and when you will get your results and who to contact.
- Keep your follow-up appointment, as the scan only helps once it has been reported and explained.
- Recent kidney blood test result, if one was requested
- List of medicines, including diabetes medicines such as metformin
- Note of any previous reaction to X-ray dye or serious allergy
- Avoided caffeine beforehand as advised
- Someone to drive you home if a sedative is planned
- A note of how and when results will be given
⚠ Get urgent help if…
- Signs of a dye reaction in the hours after the scan, such as a spreading rash, itching, swelling of the face or lips, or wheeze
- Difficulty breathing or tightness in the throat (call 999)
- Severe or worsening chest pain after the scan
- Feeling faint, very dizzy or having a very slow pulse after the heart-slowing medicine
- Pain, swelling, redness or bleeding at the cannula site that does not settle
- Passing much less urine than usual in the days after the scan, especially if you have kidney problems
Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.
General guidance — it doesn't replace the specific advice your radiologist gives you.
Results & realistic expectations
A clear scan, with arteries that look open and little or no calcium, makes significant coronary artery disease very unlikely and is reassuring. If narrowings or furring-up are seen, the report describes where they are and roughly how severe, which helps decide on medicines, lifestyle changes or a further test.
The scan is better at ruling disease out than at grading exactly how tight a narrowing is. Heavy calcium or a stent can make the pictures harder to read and can lead to a narrowing being over- or under-estimated, so an unclear or borderline result often leads to a further test such as an invasive angiogram. A normal scan also does not guarantee you will never develop heart disease, and it does not assess the heart's rhythm or pumping, which need other tests.
The scan reflects your arteries at the time it is done. A reassuring result does not last forever, because furring-up can develop or progress over the years, especially if risk factors such as high blood pressure, high cholesterol, smoking or diabetes are not managed. How long the result remains useful, and whether or when to repeat any test, depends on your risk and symptoms, and your cardiologist will advise. Repeating CT scans is weighed against the radiation dose each time.
Related tests, treatments or support
A calcium score is often done as part of the same visit. The scan is usually interpreted alongside an ECG, blood tests including cholesterol and kidney function, and sometimes an echocardiogram, because each looks at a different aspect of heart health. If the arteries need treating, an invasive angiogram, sometimes with a stent, may follow.
Follow-up & long-term care
A radiologist or cardiologist reports the scan, and your results are normally explained at a follow-up appointment, sometimes within a few days for an urgent question. They will tell you whether the arteries look clear, whether medicines or lifestyle changes are advised, and whether a further test is needed. If incidental findings were noted, they will explain what, if any, follow-up those need.
- Managing risk factors such as blood pressure, cholesterol, smoking and diabetes to slow furring-up
- Taking any heart-protective medicines as advised after the result
- Following up any incidental chest findings as recommended
- Discussing with your cardiologist if or when any repeat test is needed, balanced against radiation
Repeat, follow-on and what comes next
- An unclear or borderline scan, often from heavy calcium or a stent, frequently leads to a further test such as an invasive angiogram.
- A scan may occasionally need repeating or supplementing if heart-rate control or breath-holding limited the picture quality.
- Incidental chest findings can trigger further imaging or surveillance that was not the original purpose of the scan.
Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.
What good aftercare looks like
- A clear report reviewed by a radiologist or cardiologist, explained in plain language.
- A sensible plan for any narrowing found, balancing medicines, lifestyle and further tests.
- A defined route to follow up incidental findings, rather than leaving them unexplained.
- A named contact for results and questions, and advice on managing heart risk factors.
What affects the cost
Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:
- Whether a calcium score alone or a full CT coronary angiogram with dye is done
- The fee for the radiologist or cardiologist who reports the scan
- Whether medicines to slow the heart and contrast dye are included
- Whether a kidney blood test or other checks are needed beforehand
- Whether a consultation and discussion of results are included
- Whether follow-up for any incidental findings is covered
- The fee for the scan itself
- The reporting specialist's fee
- Any charge for contrast dye and heart-slowing medicines
- Whether a pre-scan check, such as a kidney blood test, is included
- Whether a consultation to discuss results is included
- What happens, and what it costs, if a further test such as an angiogram is needed
- How incidental findings are followed up, and at what cost
On the NHS? NICE recommends a CT coronary angiogram as a first test for many people with recent chest pain, and it is available on the NHS; private scans are usually chosen for speed, convenience or a second opinion rather than because the test is unavailable.
You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.
Consent traps and marketing red flags
These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.
Consent traps
- Not being told the scan uses radiation and a dye, and that the dye is not suitable for everyone.
- Not discussing that the scan is better at ruling disease out than at grading how tight a narrowing is.
- No plan for how incidental chest findings will be handled if they are seen.
- No clear arrangement for who reports the scan and how and when results are given.
Marketing red flags
- Promoting the scan as a one-off way to 'catch everything' or guarantee a healthy heart for life.
- Offering it as a routine screen to people with no symptoms and no clear clinical reason.
- Downplaying the radiation dose or the possibility of dye reactions and kidney effects.
- Not mentioning that incidental findings are common and can lead to further tests and worry.
Choosing a specialist safely
- Check the radiologist is on the GMC Specialist Register for this area.
- Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
- You're entitled to time to consider and to have your questions answered before you agree — the radiologist who looks after you should explain it, not a salesperson.
- Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
- You're entitled to your total cost in writing — including any follow-up — before you decide.
Questions to ask your medical professional
Take this to your consultation. A good radiologist will welcome every one of these.
- What will this scan change about my treatment or further tests?
- What happens if the result is normal, abnormal or unclear?
- Is the dye safe for me given my kidney function, allergies or asthma?
- Do I need to stop any medicines, such as metformin, before or after the scan?
- How will incidental findings in my chest be handled if any are seen?
- Would an invasive angiogram or a different test be more useful in my case?
- Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
- Will you be the radiologist who carries out my scan, and who looks after me afterwards?
- What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
- What does a realistic result look like — and what can this scan not achieve?
- What are my options, including waiting, doing nothing for now, or choosing a different approach?
- Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
- What is the total cost in writing, including any follow-ups, and how much time do I have to decide?
Frequently asked questions
Is a CT coronary angiogram available on the NHS?
Does it use radiation, and is that dangerous?
Why am I given a tablet or injection to slow my heart?
What is the difference between this and an angiogram done through the wrist or groin?
Can the scan miss a problem or give a false alarm?
What if the scan finds something unexpected in my chest?
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How we made this page
Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →
Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.
Sources & standards: NICE NG95 — Chest pain of recent onset (recommendations) British Heart Foundation — CT coronary angiogram Coronary CT angiography — StatPearls (NCBI) University Hospital Southampton NHS — CT coronary angiogram (patient leaflet) Incidental non-cardiac findings in coronary CT angiography — PMC
Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.
Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.
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