Nuclear cardiology uses small amounts of radioactive tracer and a gamma or PET camera to show how well blood reaches the heart muscle and how well the muscle works. The commonest test is the myocardial perfusion scan (SPECT or MPI), performed at rest and after stress from exercise or a medicine.
It answers a functional question that an angiogram cannot: is this heart muscle short of blood under stress, and how much of it. Its limits are radiation exposure, a test that takes several hours, and reduced accuracy when all three arteries are equally narrowed.
What Nuclear Cardiology (Myocardial Perfusion Scan) shows
Comparing stress and rest images shows areas that take up tracer normally, areas that are short of blood only under stress (reversible ischaemia) and areas that are permanently scarred from a previous heart attack. The extent of ischaemia helps decide between medicines and revascularisation. Gated images give the ejection fraction. Related nuclear tests include viability imaging with FDG PET to see whether weak muscle would recover after bypass or stenting, bone tracer scintigraphy (PYP or DPD) to diagnose transthyretin cardiac amyloidosis without a biopsy, FDG PET for cardiac sarcoidosis and prosthetic valve or device infection, and MUGA scans for precise pumping function.
When Nuclear Cardiology (Myocardial Perfusion Scan) is recommended
- People with chest pain of intermediate likelihood for coronary disease, especially if they cannot exercise or have an abnormal resting ECG
- Patients with known narrowings, to judge whether they cause ischaemia
- After bypass surgery or stenting when symptoms return
- Assessment of viability before high-risk revascularisation
- Suspected transthyretin cardiac amyloidosis or cardiac sarcoidosis
- Pre-operative risk assessment before major vascular surgery in selected patients
Limits and situations where another test is better:
- Pregnancy; breastfeeding needs a temporary pause
- Ongoing or unstable chest pain, which needs emergency care and not a stress test
- Low-risk younger patients, for whom a non-radiation test such as stress echo or CT angiography is often better
- Severe asthma rules out the stress agents adenosine and regadenoson; dobutamine is used instead
- Balanced three-vessel disease can produce a falsely reassuring scan
How to prepare
- No caffeine for 12 to 24 hours before a pharmacological stress test: that includes tea, coffee, cola, chocolate and some painkillers
- Fast for about 4 hours
- Ask whether to withhold beta blockers, nitrates or dipyridamole beforehand
- Wear comfortable shoes and clothes for the treadmill
- For FDG PET sarcoid imaging, a strict low-carbohydrate, high-fat diet followed by fasting is required the day before
- Tell staff if you might be pregnant or are breastfeeding
What happens during the test
A cannula is placed in your arm. For the stress part you walk on a treadmill or receive a drug infusion over 4 to 6 minutes that may cause flushing, chest tightness or breathlessness lasting a minute or two. Tracer is injected at peak stress. After a wait of 30 to 60 minutes you lie still under the camera with arms above your head for 10 to 20 minutes. The rest images follow the same pattern, either later that day or on a second day. Total time is 3 to 4 hours for a one-day protocol.
Results and next steps
A nuclear medicine physician and cardiologist report the scan, normally within 1 to 2 working days. A normal perfusion scan predicts a low yearly risk of cardiac events, below 1 in 100. Moderate or large areas of ischaemia usually lead to a recommendation for coronary angiography. Fixed defects point to scar, where medicines are the mainstay.
- Test time: 3 to 4 hours, sometimes over 2 days
- Results ready: 1 to 2 working days
- Back to everyday activity: None
Safety and risks
- Radiation dose roughly equal to a few years of natural background exposure; lower with PET and modern cameras
- Temporary side effects of stress drugs: flushing, headache, chest discomfort, breathlessness, and rarely wheeze or heart block
- Rare arrhythmia or cardiac event during stress, as with any stress test
- Allergic reactions to tracers are very rare
Arranging Nuclear Cardiology (Myocardial Perfusion Scan) in Türkiye
Perfusion imaging is available in most countries and is not usually a reason to travel. It is useful during a visit when it guides a treatment decision being made there, for example whether a known narrowing deserves a stent, or as part of a work-up for amyloidosis or sarcoidosis. Allow 1 to 2 days. You may set off radiation detectors at airports for a few days, so carry the letter you are given.
Send your previous reports and the question you want answered and a Clinic-Y coordinator replies within 24 hours with suitable teams and written, all-inclusive proposals side by side. Reviewing your case is free.
الأسئلة المتكررة
Is the radiation dangerous?
The dose is small and the added lifetime cancer risk is very low, but it is not zero. The test should be done only when the result will change management.
Nuclear scan, stress echo or stress MRI?
All three detect ischaemia with similar accuracy. Choice depends on local expertise, body build, lung disease, kidney function, implants and whether you can exercise.
Do I need to avoid people afterwards?
For the rest of the day, drink plenty of fluids and limit prolonged close contact with pregnant women and small children.