What is a Stress Myocardial Perfusion Scan (Stress MPI)?
Myocardial perfusion scan is an imaging test to show how well the blood is flowing through the heart muscle. It also helps find out, how well the muscles are pumping blood. After a heart attack, it finds out the area of the damaged heart during rest and while exercising.
The stress myocardial perfusion scan uses a small amount of radioactive material known as a radioactive tracer. The tracer travels through the bloodstream where it’s absorbed by the muscle. The damaged areas are not able to absorb the tracer.
The stress myocardial perfusion scan looks different in the areas where tracer has been absorbed and where it is not absorbed.
A stress myocardial perfusion scan assesses the blood flow to the heart muscle when it is stressed. If the patient is not able to exercise, a certain medication is given to increase the heart rate or dilate the blood vessels as it would occur during exercise.
Who Might Need A Stress Myocardial Perfusion Scan (Stress MPI)?
A stress myocardial perfusion test tells a doctor whether the heart is getting enough blood. It is also known as a nuclear stress test.
A person might need the stress myocardial perfusion test if:
- There is chest pain because of narrowed or blocked arteries.
- After a person has had a heart attack and the doctor wants to find out the shape of the heart.
- A doctor wants to make sure that a stent or a bypass is working properly.
Pre-Procedure Guidelines
A person may be asked to follow a few things before the stress myocardial perfusion test procedure:
- Stop taking a certain medication
- Avoid food and drinks especially those with caffeine a day before the stress myocardial perfusion test.
- Avoid eating and drinking anything up to 6 hours before the stress myocardial perfusion test begins.
- A doctor needs to be informed if a female is pregnant or breastfeeding as the radiation can harm the baby or can be passed to the baby through breast milk.
- Wear comfortable shoes as you might be asked to exercise.
- Do not wear any jewelery or metal during the stress myocardial perfusion test.
How is a Stress Myocardial Perfusion Scan (Stress MPI) Performed?
Small patches are put on the chest, arm, and legs which have wires hooked up to a machine. This machine tracks the heart rate. A cuff is put on the arm to record the blood pressure.
The patient is asked to exercise either on a treadmill or a bicycle. Near the end of the exercise, a small amount of radioactive material known as the tracer is inserted into the bloodstream. This mixes with the blood as it is pumped through the body.
The patient is made to lie down on a table and with the help of a gamma camera pictures of the heart are taken. The camera will pick the images and show where the blood is getting to the heart and where it isn’t.
If the patient cannot exercise, a drug that dilates or widens the arteries is given after which tracer is given. After this, the patient rests for some time and again the images are taken to compare with the previous stressed state.
The entire stress myocardial perfusion scan procedure takes up to 4 hours.
Post-procedure
After the stress myocardial perfusion scan procedure, an appointment with the doctor is taken to discuss the result.
The body gets rid of radioactive tracer through urine or stool in a day. The patient is advised to drink extra fluid to flush it out well.
The Risk Associated With Stress Myocardial Perfusion Scan (Stress MPI)?
There are a lot of risks associated with myocardial perfusion test such as:
- The person might experience chest pains or the heart rhythm might get disturbed. Inform the doctor if it happens.
- Some people might get allergic reactions from the tracer or the drug used.
- Soreness at the place from where the tracer is inserted.