Myocardial perfusion imaging or scanning (also referred to as MPI or MPS) is a nuclear medicine procedure that illustrates the function of the heart muscle (myocardium).

The history of nuclear cardiology began in 1927 when Dr. Herrmann Blumgart developed the first method for measuring cardiac strength by injecting subjects with a radioactive compound known as Radium C (214Bi).

Similarly, if tissue damage (heart attack, myocardial infarction, cardiac stunning or hibernation) is to be determined, this is done under "resting" conditions.

By 1963, Dr. William Bruce, aware of the tendency of people with coronary artery disease to experience angina (cardiac chest discomfort) during exercise, developed the first standardized method of "stressing" the heart, where serial measurements of changes in blood pressure, heart rate and electrocardiographic (ECG/EKG) changes could be measured under "stress-stress" conditions.

The utilization of Tc-99m would allow higher doses (up to 1,100 MBq or 30 mCi) due to the shorter physical (6 hours) half life of Tc-99m.

This would result in more decay, more scintillation and more information for the nuclear cameras to measure and turn into better pictures for the clinician to interpret.

[12] Myocardial perfusion imaging scans are "powerful predictors of future clinical events", and in theory may identify patients for whom aggressive therapies should improve outcome.

[12] However, several trials have indicated the high sensitivity (90%) of the test, regardless of tracer, outweighing any potential detrimental effect of the ionising radiation.

[15] The power of prognosis from a myocardial perfusion scan is excellent and has been well tested, and this is "perhaps the area of nuclear cardiology where the evidence is most strong".