stress MRI what to expect

Overview

A stress MRI (magnetic resonance imaging) is a detailed scan that takes pictures of your heart while it is working harder than usual, similar to when you exercise. It helps doctors see how well blood is reaching your heart muscle and can identify areas that are not getting enough blood.

A stress MRI is a specialised test. It is not as routine as an ECG or a stress test on a treadmill, but it is used in many hospitals and heart centres, including some NHS centres in the UK.

It is used for people who have symptoms such as chest discomfort or breathlessness, and for those with known heart conditions or risk factors like high blood pressure, diabetes, high cholesterol, smoking, or a family history of heart disease.

Symptoms

Common symptoms

• Chest pain, tightness, or pressure
• Shortness of breath
• Unexplained tiredness or reduced ability to exercise
• Palpitations or an unusually fast or irregular heartbeat
• Dizziness or light-headedness during activity

Symptoms in children

• Chest pain or discomfort during physical activity
• Breathlessness or getting tired more quickly than other children during play or sport
• Fainting or near-fainting during or after exercise

Symptoms in older adults

• Shortness of breath with minimal activity
• Chest discomfort that is less typical, such as a dull ache or indigestion-like feeling
• Increased fatigue or difficulty doing daily tasks
• Swelling in the legs or ankles

Causes

Main causes

• The most common reason for a stress MRI is to look for reduced blood flow to the heart muscle, often caused by narrowing of the coronary arteries due to fatty build-up (atherosclerosis).
• It can also be used to assess the effect of a previous heart attack, or to check for problems with the heart muscle such as thickened or weakened areas.
• Sometimes it helps doctors understand why someone has symptoms such as chest pain even when the arteries look clear on other tests.

Risk factors

• High blood pressure
• High cholesterol
• Diabetes
• Smoking
• A family history of early heart disease
• Being physically inactive
• Carrying extra weight, especially around the waist
• Increasing age, usually mid-40s and older

When to see a doctor

See a doctor urgently if:

• If you have chest pain or breathlessness that happens for the first time, is getting worse, or is happening with less activity than before, contact your GP or local same-day medical service.
• If you are waiting for a stress MRI and any symptoms become more frequent or severe, tell your healthcare team.

Book a routine appointment if:

• If you notice a change in your exercise tolerance, such as feeling more short of breath than usual, make a routine appointment with a doctor.
• If you have risk factors for heart disease and have never discussed your heart risk, ask for a heart health check.

Diagnosis

A doctor will decide if a stress MRI is the right test based on your symptoms, medical history, a physical examination, and other tests such as an ECG (electrocardiogram) or blood tests. The scan is a diagnostic imaging test, not a treatment.

Tests that may be done

• ECG to check the heart's electrical activity
• Blood tests to look for markers of heart strain or risk factors
• An exercise tolerance test (treadmill or bicycle test) before deciding if stress MRI is needed
• Echocardiogram (an ultrasound of the heart)

What to expect at your appointment

Before the scan, the doctor or nurse will explain the procedure and ask about your medical history, medicines, and allergies. You will usually be asked to avoid caffeine for 24 hours before the test and not to eat or drink for a few hours beforehand. At the hospital, you may change into a gown. An intravenous drip will be placed in a vein in your arm. You will lie on a table that slides into a large scanner shaped like a tube. The team will monitor your heartbeat, blood pressure, and breathing. You will be asked to hold your breath for short periods to get clearer images. To stress the heart, you may either exercise on a special device or receive a medicine through the drip that makes your heart respond as if it is exercising. A contrast dye may be injected through the drip to make the images clearer. The scan usually takes between 45 minutes and an hour. You should not feel pain, though the medicine can make you feel flushed, breathless, or slightly dizzy; these feelings normally pass quickly.

Treatment

Treatment depends on what the stress MRI finds. If the results are normal, you may not need any treatment. If areas of reduced blood flow are found, your doctor will talk with you about a plan to improve your heart health and protect your heart muscle.

Self-care at home

• Follow the preparation advice you are given, such as avoiding caffeine and not eating for a few hours before the scan.
• Bring a list of your current medicines to the appointment so the team can review it.
• Tell the team if you have kidney problems, allergies, or are pregnant or breastfeeding.
• Wear comfortable clothes and shoes; you may need to change into a hospital gown.
• Arrange for someone to take you home if you feel unsteady after the test, or if you are told the medicine may make you drowsy.

Medical treatments

If the scan shows a heart condition, treatment is tailored to your situation. It may include lifestyle changes, medicines to lower blood pressure or cholesterol or to help the heart work more efficiently, and sometimes procedures to improve blood flow. Your healthcare team will explain the options and how each may help. Never stop or change any heart medicine without speaking to your doctor.

When is surgery considered?

If a stress MRI shows significant narrowing or blockages, some people need procedures such as angioplasty and stenting (opening a narrowed artery with a small balloon and placing a mesh tube) or coronary artery bypass surgery (creating a new route for blood using a healthy blood vessel). Your heart team will discuss whether this is needed in your case.

Living with this condition

A stress MRI is a one-off diagnostic test, but living with a heart condition is about long-term care. Follow your doctor's advice, take prescribed medicines as directed, and attend follow-up appointments. It may help to keep a simple record of your symptoms, such as when they happen and what brings them on, to share with your care team.

Lifestyle tips

• If you smoke, ask for help to quit.
• Limit alcohol to levels your healthcare team advises.
• Choose heart-healthy foods such as vegetables, fruit, whole grains, and lean proteins.
• Stay active at a level that is safe for you; ask your team what activity is best.
• Manage stress with talking, breathing exercises, or gentle hobbies.

Diet and exercise

A balanced diet low in saturated fat, salt, and added sugar can support heart health. The exact diet and exercise plan depends on your test results and any other conditions you have. Your medical team or a dietitian can give you advice that fits your situation. In general, aerobic activity like walking, cycling, or swimming, plus light strength training, is helpful for many people with heart conditions, but check with your team first.

Mental health and emotional wellbeing

Waiting for test results or learning that you have a heart condition can be stressful. It is common to feel anxious, worried, or low. Talking to a trusted friend, family member, or a professional counsellor can help. If you are in crisis, contact your local emergency number or mental health crisis service.

Prevention

You cannot always prevent heart disease, but a stress MRI can help find problems early so they can be treated. Managing blood pressure, cholesterol, diabetes, and weight, and taking medicines as prescribed, can lower your risk of further damage.

Vaccines

There are no vaccines to prevent the conditions a stress MRI is looking for. But staying up to date with recommended vaccinations, such as flu and COVID-19, can reduce the extra strain infections can place on the heart.

Screening programmes

A stress MRI is not a screening test for the general population. It is used when a doctor needs more information about the heart. Blood pressure checks and cholesterol tests are routine screenings that can help detect risk early.

Complications

If left untreated

• If reduced blood flow to the heart is not addressed, it may increase the risk of a heart attack.
• It can lead to worsening shortness of breath, extreme tiredness, or heart failure, which means the heart cannot pump blood as well as it should.
• Some heart rhythm problems can become more likely.

Long-term outlook

Most people find the diagnostic process reassuring because it gives clear information. If a problem is found, there is a great deal that can be done. Medicines, procedures, and lifestyle changes help many people feel better and prevent the condition from getting worse. The earlier a problem is found, the more can be done to help.

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