Myocardial perfusion scan (nuclear cardiology)
A nuclear medicine scan that uses a small amount of radioactive tracer to show how well blood reaches the heart muscle, at rest and when the heart is made to work harder.
✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review
In short
- A nuclear scan that uses a small radioactive tracer to show how well blood reaches the heart muscle, at rest and under stress.
- It shows areas of muscle short of blood or permanently damaged, rather than picturing the arteries directly.
- It involves a small dose of radiation and a stress medicine or exercise; serious problems are rare but the test is supervised.
- A normal scan is reassuring about blood supply but does not rule out every heart problem; the result needs specialist interpretation.
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 parts of the heart muscle are short of blood when the heart works hard.
When the question is really about the anatomy of the arteries, a CT coronary angiogram may be the better first test.
Staff monitor your heart rhythm and blood pressure. Any flushing, breathlessness or chest tightness from the medicine usually passes within minutes, and a...
Clear explanation of the result in the context of your symptoms and other tests.
Staff monitor your heart rhythm and blood pressure. Any flushing, breathlessness or chest tightness from the...
You wait for the tracer to settle, then lie still under the camera for each set of images. There may be a gap of...
The cannula is removed. You can normally eat, drink, drive and return to normal activity straight away.
Drinking fluids helps clear the tracer, which leaves the body naturally over the next day or so. Any cannula-site...
What is a myocardial perfusion scan?
A myocardial perfusion scan is a nuclear medicine test that shows how well blood is reaching the muscle of your heart. A small amount of a radioactive substance, called a tracer, is injected into a vein and travels to the heart muscle in proportion to its blood supply. A special camera then detects the tracer and builds pictures showing which parts of the muscle are well supplied and which are not.
The scan is usually done in two parts: at rest, and under stress, when the heart is made to work harder either by exercise or, more often, by a medicine that mimics exercise. Comparing the two sets of pictures shows whether any area of muscle is short of blood when the heart works hard (suggesting a narrowed artery) and whether any area is permanently damaged, for example by a previous heart attack.
It is used mainly to investigate chest pain that might be angina, to assess known coronary artery disease, and to help decide whether treatments such as stents or bypass surgery are likely to help. It tells you about blood flow to the muscle rather than showing the arteries directly, and it uses a small dose of radiation, so it is chosen when that information is genuinely useful.
Types, options & approaches
There may be different ways to do this. The right approach depends on the clinical question and your circumstances.
Perfusion scan versus CT coronary angiogram
| Feature | Perfusion scan | CT coronary angiogram |
|---|---|---|
| What it shows | Blood flow to the muscle | The arteries themselves |
| Stress needed | Yes (medicine or exercise) | Not usually |
| Radiation | Small dose, from a tracer | Small dose, from X-rays |
| Best when | Judging if a narrowing matters | Looking for narrowings |
The scans answer different questions and are sometimes used in sequence. Your cardiologist decides which suits your situation.
Preparing for your scan
- Avoid caffeine, including coffee, tea, cola, energy drinks, decaffeinated drinks and chocolate, for around 24 hours, as it interferes with the stress medicine.
- Ask which heart and other medicines to take or hold; some, such as certain asthma medicines, beta-blockers or dipyridamole, may need adjusting.
- Tell the team if you have asthma or a wheezy chest, as this affects which stress medicine is safe.
- Tell the team if you are or might be pregnant or are breastfeeding, as special precautions apply.
- Wear comfortable clothes and footwear suitable for exercise if you are having an exercise scan.
- Eat only a light meal as advised, and allow several hours for the whole appointment.
- Arrange your day around a possible long visit, or a second visit if a two-day protocol is used.
What happens
A small cannula is placed in a vein, usually in the arm. For the stress part, you either exercise on a treadmill or bike, or are given a medicine through the cannula that mimics exercise for a few minutes; this can cause brief flushing, breathlessness, a headache or chest tightness that quickly passes. At the right moment the radioactive tracer is injected.
After a wait, often around 30 to 60 minutes, you lie under a special camera that rotates around your chest to take pictures of the heart muscle; each set of images takes roughly 15 to 30 minutes and you need to keep still. A rest set of images is taken in the same way, either before or after the stress set, sometimes on a second day.
Throughout the stress part your heart rhythm and blood pressure are monitored by trained staff, who can stop the test at any time. Once the images are complete you can usually go home and return to normal activities, including driving.
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…
- When the question is really about the anatomy of the arteries, a CT coronary angiogram may be the better first test.
- Severe asthma or certain breathing conditions can make some stress medicines unsafe; an alternative is needed.
- Pregnancy, where the radiation dose is usually avoided unless essential.
- People who cannot keep still enough under the camera for diagnostic images.
- Where the result would not change management, exposing someone to radiation is hard to justify.
Delay or rearrange if…
- Recent caffeine intake that could block the stress medicine.
- An acute illness, chest infection or unstable symptoms needing assessment first.
- Medicines such as certain asthma treatments or dipyridamole that need adjusting beforehand.
- A recent heart event where stress testing should wait.
- Possible pregnancy that needs confirming or excluding first.
Alternatives to discuss
- A CT coronary angiogram to look directly at the arteries, often preferred for new chest pain.
- A stress echocardiogram, which uses ultrasound and no radiation.
- A stress perfusion cardiac MRI, which also avoids X-ray radiation.
- An invasive coronary angiogram where treatment of a narrowing is likely.
- No imaging, if the question can be answered another way.
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.
Comfort, sedation or contrast choices
If local anaesthetic, sedation, contrast or pain relief is used, ask what is planned, why, and what it means afterwards.
Benefits
- Shows whether parts of the heart muscle are short of blood when the heart works hard.
- Helps tell reversible shortage of blood from permanent muscle damage.
- Helps work out whether a narrowed artery is actually affecting the heart.
- Can guide decisions about stents, bypass surgery or medicines.
- Useful when an exercise ECG is unreliable or not possible.
- Gives functional information that complements scans showing the arteries.
Risks & complications
- Brief flushing, headache, breathlessness or chest tightness from the stress medicine, which wears off quickly.
- Bruising or discomfort where the cannula is placed.
- Having to lie still under the camera for each set of images.
- A longer or stronger reaction to the stress medicine needing a reversal drug.
- An abnormal heart rhythm during the stress part, usually settling when it stops.
- An incidental finding that leads to further tests.
- A borderline or unclear result needing another test.
- A serious reaction to the stress medicine, especially wheezing in people with asthma.
- A heart attack or dangerous rhythm triggered by stress; staff are trained to respond.
- The very small, long-term risk associated with the radiation dose.
The main considerations are the stress medicine, which can briefly cause unpleasant but short-lived symptoms and must be chosen carefully in people with asthma, and the radiation, which carries only a very small long-term risk that is outweighed by the information gained when the test is genuinely needed. As with other tests, a normal scan does not rule out every problem, and incidental or borderline findings can lead to more tests. Ask whether this scan, rather than an alternative, is the best way to answer your particular question.
Published figures to discuss
Serious complications of the stress test are rare but real, which is why it is supervised. The radiation dose is small but not negligible, and estimates of long-term cancer risk are based on cautious modelling rather than directly observed harm, so they should be understood as very small and uncertain. Diagnostic accuracy and incidental findings are the other practical uncertainties.
| Figure | Reported range | How to interpret it | Source / confidence |
|---|---|---|---|
| Serious complication during stress testing | Rare; major adverse events are reported at well under 1 in 1,000 in stress-testing series | Staff monitor you throughout and can stop the test and give treatment; risk is higher with significant underlying heart disease. | Reducing radiation exposure from nuclear myocardial perfusion imaging — review (PMC)pmc.ncbi.nlm.nih.govPublished figure |
| Radiation dose and long-term risk | Typical effective dose around 10 mSv or so, depending on tracer and protocol | Doses vary widely by protocol; the long-term cancer risk is very small and based on cautious modelling, and is justified by the information gained. | Reducing radiation exposure from nuclear myocardial perfusion imaging — review (PMC)pmc.ncbi.nlm.nih.govSource-linked context |
| False-positive or artefact | Recognised | Breast tissue, diaphragm position, body habitus and movement can create attenuation artefacts, so results need expert interpretation. | Guide sourcesClinical context |
| False reassurance | Recognised | A normal perfusion scan lowers the likelihood of significant flow-limiting disease but does not remove all cardiovascular risk. | Reducing radiation exposure from nuclear myocardial perfusion imaging — review (PMC)pmc.ncbi.nlm.nih.govSource-linked 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 beyond any brief effects of the stress medicine wearing off. Most people return to normal activities the same day. The wait that matters is for a specialist to report the images and for your cardiologist to explain them.
- A short-lived flushed feeling, headache or breathlessness from the stress medicine.
- Mild bruising where the cannula was placed.
- Feeling a little tired after a long appointment.
- No lasting effects and a normal return to daily life.
- A wait of days to weeks for the report.
Aftercare
- Drink plenty of fluids to help clear the tracer from your body.
- Resume normal activity, eating and driving unless told otherwise.
- Restart any medicines that were paused, as advised.
- It is sensible to keep a little distance from very young children and pregnant people for the rest of the day, if advised, as a precaution.
- Look after the cannula site and keep it clean if sore.
- Note any symptoms during the stress part to discuss with your cardiologist.
- Make sure you know when and how you will get your results.
- Caffeine avoided for about 24 hours beforehand
- Advice on which medicines to take or hold
- Asthma or wheeze mentioned to the team
- Comfortable clothes and footwear if exercising
- Light meal only, and a long appointment planned for
- Way to get home arranged
- Clear plan for how results will reach you
⚠ Get urgent help if…
- Chest pain that does not settle after the stress part of the scan.
- Severe or persistent breathlessness or wheezing after the stress medicine.
- Fainting, collapse or feeling about to pass out.
- A very fast, irregular or pounding heartbeat that does not settle.
- Pain spreading to the arm, neck or jaw with sweating or nausea; call 999.
- Sudden weakness, facial droop or slurred speech; call 999.
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 normal scan, where blood flow to the heart muscle looks even at rest and under stress, is reassuring and suggests no major narrowing is limiting blood supply, though it does not rule out every heart problem or guarantee the future. An abnormal scan may show an area that is short of blood only under stress, pointing to a narrowed artery that might benefit from treatment, or a fixed defect suggesting permanent damage from a previous heart attack.
The scan shows blood flow rather than the arteries themselves, so the result is interpreted alongside your symptoms and other tests. A specialist compares the rest and stress images to reach a conclusion, and reporting takes time because the images need careful analysis.
The scan reflects blood supply to the heart muscle around the time of the test. Coronary disease can progress, and symptoms can change, so a normal result does not stay valid indefinitely. Your cardiologist will advise whether and when a repeat scan or a different test is worthwhile, balancing the benefit against the radiation dose involved.
Related tests, treatments or support
A perfusion scan is often interpreted alongside an ECG, echocardiogram, blood tests and your symptoms. Depending on the findings, it may be followed by a CT coronary angiogram to look at the arteries, or an invasive coronary angiogram where treatment of a narrowing is being considered.
Follow-up & long-term care
After the scan a specialist reports the images and sends the findings to your cardiologist, who explains what they mean and whether any further test or treatment is needed, usually at a follow-up appointment. Ask before you leave how and when you will get the result and who to contact with questions.
- Attend any repeat or further tests your cardiologist arranges to track your heart.
- Keep records of previous scans so changes over time can be compared.
- Tell future clinicians about recent nuclear scans, as repeated radiation doses add up.
- Follow advice on managing risk factors such as blood pressure, cholesterol and smoking.
Repeat, follow-on and what comes next
- A borderline or unclear scan may lead to a further test rather than a final answer.
- A non-diagnostic scan, for example from movement or body habitus, may need repeating.
- Repeat scanning over time is sometimes needed, balanced against cumulative radiation.
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
- Clear explanation of the result in the context of your symptoms and other tests.
- A defined next step if the result is normal, abnormal or borderline.
- Advice on managing risk factors alongside any test result.
- A named contact route for questions or new symptoms.
- A written result and report shared with you and your GP.
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:
- The scan protocol, including whether it is done over one day or two.
- The radioactive tracer and stress medicine used.
- Whether exercise or pharmacological stress is needed, and the staff time involved.
- The specialist reporting of the images.
- Any consultation before and after to discuss the result.
- Whether the scan is part of a wider set of heart tests.
- The scan fee, including the tracer and stress medicine.
- The staff and monitoring during the stress part.
- The specialist reporting of the images.
- Any consultation to discuss the result.
- What happens, and what it costs, if a further test is needed after a borderline result.
- How and when the result and report will be provided.
On the NHS? Myocardial perfusion scans are available on the NHS when assessing blood supply to the heart muscle is clinically needed; private scans are sometimes chosen for speed or convenience.
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 radiation dose and why the scan is justified.
- No discussion of asthma or other conditions before choosing the stress medicine.
- Being told a normal scan rules out all heart disease.
- No clear plan for what an abnormal or borderline result will lead to.
- Not knowing how and when results will be given.
Marketing red flags
- Promoting a nuclear scan as a complete heart check for people with no symptoms.
- Downplaying the radiation dose or the need to justify it.
- Not mentioning the brief but unpleasant effects of the stress medicine.
- Implying the scan shows the arteries directly when it shows blood flow.
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 is this scan looking for, and why is it better than another test for me?
- Will I have a stress medicine or exercise, and what should I expect from it?
- Which of my medicines should I take or hold, and is the stress medicine safe with my asthma?
- What will a normal or abnormal result change about my treatment?
- How much radiation is involved, and is it justified in my case?
- What happens if the result is borderline or an incidental finding turns up?
- 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 the radioactive tracer dangerous?
Why must I avoid caffeine before the scan?
What does the stress medicine feel like?
I have asthma; can I still have the scan?
Will a normal scan mean my heart is completely fine?
Do I need to avoid people after the scan?
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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: British Heart Foundation — Myocardial perfusion scan NHS — Cardiac (myocardial perfusion) scan, North Cumbria Integrated Care Guy's and St Thomas' NHS — MPI scan overview Reducing radiation exposure from nuclear myocardial perfusion imaging — review (PMC) NICE — Recent-onset chest pain of suspected cardiac origin (CG95)
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.
Related guides: CT coronary angiogram · Coronary angiogram (cardiac catheterisation) · Exercise tolerance test (treadmill test) · Echocardiogram (heart ultrasound) · Cardiac MRI