Myocardial perfusion scan (nuclear stress test)

The myocardial perfusion scan (nuclear stress test) looks at blood flow to the heart during exercise and while at rest.

Your doctor may order this test if you’ve had chest pain, shortness of breath or if they think there could be a blockage in your coronary arteries (vessels that supply blood to the heart).

If you’re pregnant or breastfeeding, you may not be able to have this test.

Before your appointment

Your appointment letter will tell you if you need to stop taking any medication before the test. If you have any questions, call the clinic a few days before.

For 48 hours before the test: avoid nicotine, including smoking, vapes with nicotine, or nicotine patches.

For 24 hours before the test: avoid caffeine, including tea, coffee, energy drinks, cola and chocolate.

For 4 hours before the test: don’t eat or drink anything except water.

Wear clothes and shoes that are comfortable for walking on a treadmill.

What happens?

You will have this test at a hospital or in a clinic and it can take most of the day.

There are two parts to the test:

1. resting scan
2. stress scan, which involves exercise on a treadmill.

There is usually a two to three hour gap between the scans.

Part 1: resting scan

You’ll be asked to remove clothing from above the waist, and you’ll be given a gown.

An IV (intravenous) line will be put in your arm. A small amount of radioactive dye is injected into a vein through the line. The dye is not harmful. You’ll need to wait 40 minutes for the dye to reach the heart.

You’ll be asked to lie on your back on the scanning table. The scanner will take different views of your heart. The dye will show the flow of blood through your coronary arteries. The scan takes around 40 minutes.

Part 2: stress scan

Sticky pads (electrodes) will be placed on your chest to monitor your heart rate.

You will walk on a treadmill for 10–15 minutes while your heart rate and blood pressure are monitored. As the exercise gets more intense, the dye will be injected via the IV line and you will be asked to continue to exercise for a short time.

You’ll then rest for 30 minutes and a second scan will be performed.

After the test

Drink plenty of water to help flush the dye from your system.

You won’t get the results on the day. They will be sent to the doctor who ordered the test.

Key things to remember