Myocardial Perfusion Imaging Test Overview
A myocardial perfusion imaging test, also known as an MPI, is a nuclear medicine imaging procedure that utilizes 99mTc-Tetrofosmin (a radioactive tracer used for heart scanning) to assess for decreased blood flow in the heart vessels. Additionally, it can be particularly useful to evaluate the heart, post stent surgery, post CABG and diagnosis a variety of heart rhythm abnormalities. This test provides vital insights into cardiovascular health by revealing any obstructions or abnormalities in blood circulation, aiding in diagnosis and treatment planning for various cardiac conditions.
- We do not use a dye or contrast for this exam; therefore, it is safe for patients with kidney issues/failure.
The Myocardial Perfusion Imaging test will take approximately 3.5 to 4 hours. The test time includes the pre-test intake, resting nuclear image, the exercise and recovery period and the stress image.
For the rest portion of the test, the technologist will set up an IV in your arm. Through the IV line, a small amount of radioactive tracer (99mTc-Tetrofosmin) will be administered intravenously. It will not make you feel any different. Rest images will be acquired after a minimum of 45 minutes for approximately 10 minutes. Following the rest imaging there a waiting period of approximately 60-120 minutes. You are welcome to bring a book or something to keep yourself entertained during this wait period.
Patients will then be stressed one of two ways for their stress test. Either on the treadmill or using a drug called dipyridamole (pharmacological stress test).
If the treadmill is used, ECG leads are attached to the chest to monitor your heart while you exercise. Treadmill stress test will begin with a warmup stage and then speed is gradually increased with inclination. The patient shall be exercised to a predetermined target heart rate calculated based on age. There is also monitoring of blood pressure, heart rate and heart rhythm before, during, and after the testing. A small amount of a radioactive tracer (99mTc-Tetrofosmin) will be administered again intravenously at peak stress as part of the Exercise Stress Test.
If the pharmacological stress test is used, the stress test will be performed by infusing a vasodilator (Dipyridamole) via IV over 4 minutes and then either marching on the spot or using hand weights to increase circulation of the dipyridamole. A small amount of 99mTc-Tetrofosmin (a radioactive tracer) will be administered via IV at the 7-minute mark. Once in recovery stage, a reversal to counteract any side effects of the Dipyridamole, will be given. You will not feel any differently from the injection of the Radioactive Tracer.
ECG and vitals will be taken before, during, and after the stress test is given. Medical staff and assistants will assist during and after treadmill exercise stress test as required.
The stress images will be taken approx. 30-60 minutes after completion of stress portion. The doctor and technologist will be happy to answer your questions before you leave. A detailed report will then be typed up and sent to your doctor.
