What is a
Nuclear Scan?
A nuclear scan is a method of examining the heart in order to
get information about the blood supply to the heart muscle. Special
cameras take a series of pictures of the heart during the scan. A
radioactive substance or tracer, is injected into the
bloodstream. The tracer attaches to certain cells and makes them visible
to the special camera. The tracer attaches to the muscle cells of the
heart so the imaging camera can take pictures of the heart muscles. If an
area of the heart does not have a good blood supply, then the cells in
that area will not receive as much tracer. This will show up as a darker
area on the picture taken by the camera.
How should I prepare
for this test?
To prepare for the adenosine stress test, do not eat or drink after
midnight. Please do not drink or eat anything containing caffeine for 48
hours before the test; this includes decaffeinated coffee, pops, teas, and
chocolate. Please do not smoke on the day of the test. If you are
diabetic, you will need special instructions from your doctor or the
clinic nurse.
Most medications are taken as usual:
however, some medications may interfere with results of the adenosine
stress test. For example, if you are taking theophylline, persantine, or trental,
be sure to talk with your doctor or the clinic nurse. You will be told to
stop taking some medications so that they will not interfere with the
scan. If you have any questions about any other medications be sure to
ask. All patients should bring a list of current medications they are
taking to assist the staff. If you have asthma or other lung problems, be
sure to bring your inhalers with you. Occasionally a medicine other than
adenosine may be recommended.
During the examination
Once an intravenous (IV) line is started a small amount of a radioactive
substance called or tracer is injected into the bloodstream. After allowing
time for the tracer to circulate the first pictures will be done. You
will lie flat on a table with your left arm above your head. The
technologist will help you get comfortable. A large imaging camera will be
brought close to your chest for the scans. A technologist will make the
necessary adjustments and the imaging will begin. It is important to lie
still during the scan. A technologist will be nearby if you need anything.
This part of the scan lasts about 25 minutes. This set of pictures will
show blood flow to the heart muscle in the resting state.
Next you will be
connected to a R lead ECG as well as a blood pressure cuff and an oxygen
monitor. Your vital signs will be monitored closely during the infusion of
the adenosine. Prior to starting the adenosine a nurse will explain any
symptoms you may feel. Staff members present are an ECG tech, a nurse and
the Cardiologist (a physician who specializes in heart disease). During the infusion of the Adenosine a second
radioactive tracer is injected.
The second set of pictures will be taken
approximately one hour after you receive this injection. You will be free
to wait in the waiting room or go to the cafeteria. You may drink fluids
that do not contain caffeine, or sugar and may eat anything at this time.
Ask the technologist when you should
return to the Radiology area to complete the second set of scanning
which will take about another 25 minutes. You can expect the entire test
to take approximately 3 to 4 hours.
What does the
nuclear stress test show?
- If the test is normal during bothexercise and rest, then blood flow through the coronary arteries is
normal.
- If the test shows that perfusion isnormal during rest but abnormal during exercise (a perfusion defect),
then the heart isn’t receiving enough blood in when it has to work
harder than normal. This may be due to some blockage in one or more
coronary arteries.
- If the test is abnormal during bothexercise and rest, there’s limited blood flow to that part of the
heart at all times.
- If no tracer is seen in some part ofthe heart muscle, it means that this part of the heart has had a
previous heart attack and the cells are dead. (They have become scar
tissue.)
Is the
nuclear stress test dangerous?
It is unlikely that you will feel any effects from the injection. The
amount of radiation you will be
exposed
to is no more than you would receive from other x-ray tests and is not
harmful to you. However,
if there is any chance you might be pregnant, please notify your doctor.
Where should I go for
my nuclear stress test?
Please report to the St. Alexius Medical Center admission’s area located
on l0th Street they will then direct you to the Radiology / Special
Imaging department where you will be checked in.
How will I get my
results?
Your doctor will be given the results of your test within one to two days.
You will be contacted by your doctor or a return visit may be scheduled to
discuss the results.
Back