MIBI is fun to say · 21 September 05
Myocardial Perfusion Imaging (MIBI) -
A small amount of radioactive solution, or tracer, is injected into a vein in your arm. The injection is like a routine blood test and will not make you feel dizzy or sick (although the solution is radioactive, you are not exposed to a dangerous amount of radioactivity).
The tracer travels in your blood stream to your heart, where it lodges itself in the healthy, active heart muscle cells. This takes about one hour (and four glasses of water) to happen.
The radiologist takes two sets of pictures of your heart with a gamma camera; one while you are resting (day one) and one while you are under stress (day two).
The stress part involves being hooked up to an ECG machine while walking on a treadmill. The tacer is injected into your vein, through an IV put in ahead of time, when your heart rate hits its target beats per minute (mine was 159 bpm). You then wait one hour (and two glasses of water) before jumping back under the gamma camera for the second set of images.
If you have had a heart attack, some of your heart muscle may be dead, so not all the cells will trap the tracer. If you have coronary heart disease some of your heart muscle cells will not trap the tracer because not enough blood and oxygen gets to your heart when you exercise. The doctors can see the difference between the two conditions by comparing your ‘rest’ pictures with your ‘stress’ pictures. If you have coronary heart disease, your stress pictures may be abnormal and your rest pictures normal. Both sets of pictures may be abnormal if you have had a heart attack. If the stress pictures are normal you will not have a resting scan as the heart function is normal on exercise.
The clinic may advise you to avoid prolonged close contact with children for the rest of the day to avoid exposing the children to unnecessary radiation. When they have the results, you doctor or cardiologist will want to discuss them with you. They will be able to establish a suitable course of treatment from your results or discuss further investigations
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