Myocardial Perfusion Scan
Myocardial perfusion scan is a cardiac diagnostic procedure using nuclear medicines so as to analyze cardiac functions and reveal any problems related to cardiac muscles. Myocardial perfusion scan helps to evaluate various cardiac diseases or dysfunctions ranging from coronary vessel block up to the hypertrophic diseases of heart like the cardiomyopathy or ventricular abnormalities. It also illustrates the left ventricular ejection fraction of the heart, and therefore gives an idea of the ventricular pumping effect. Myocardial perfusion scan is done along with cardiac stress test.
Some of the major indications for myocardial perfusion scan include the following:
- For the diagnosis of the coronary artery disease and other cardiac anomalies
- To identify the degree of coronary vessel block in patients with a previous history of the coronary disease.
- For evaluating the cardiac function after revascularization surgeries or following stenting method
There are various advantages and risks associated with myocardial perfusion scan. In a research study conducted by exposing patients to low dosage radiations of ionizing type, it was seen that myocardial perfusion scan had the largest average of effective dosage. Of all the radiological procedures, including the tomographic studies Myocardial perfusion scan is found to be highly effective with a fairly good percentage of dose. Older patients had the highest dosage of even 5.27 percent getting about 20 -50 mSv/year and 0.57% having a dose of more than 50mSv/ year from almost every sources available.
How Myocardial Perfusion Scan Works?
Myocardial perfusion scans has now proved to be a strong and powerful predictive diagnosis for analyzing the future events. In myocardial perfusion scan, a slight amount of radioactive material that is referred to as a radioactive tracer or radionuclide is infused to aid in the tissues examination which is under observation. Myocardial imaging as its name refers is used for imaging or evaluating the cardiac blood flow and muscle functions.
The radionuclide that is injected into the body will travel through the blood circulation and get absorbed by the healthy cardiac muscles. But the unhealthy or poor heart muscles may fail to take up the tracer and will be seen in a different color. Any block in the blood flow or damage to the muscles can be easily identified with this cardiac imaging technique. Cardiac scanning is started with the infusion of the tracer and is continued throughout the procedure to assess any abnormality that is noticed meanwhile. The radiopharmaceutical used in myocardial perfusion scan is either technetium or thallium and this is infused into a vein in the hand or arm.
There are different types of radioisotopes which serving the purpose in various scans. If certain type of nuclides are used, then the area which does not absorb the same will appear as defective areas or something called as cold spots in the scan. Whereas in some other types, these radiotracers will bind with the calcuim released during a heart attack, and thus will accumulate as hot spots in the area of the injured cardiac tissues.
Things to remember while undergoing Myocardial Perfusion Scan
Myocardial resonance imaging is highly effective and less painful. There are also certain things that a patient should keep in mind once they undergo the myocardial imaging scan. The patient should take plenty of water after the procedure so as to wash out the dye from the body. Patient should remain in the bed for at least 24 hours by immobilizing the arm or hand punctured for the procedure. It is very important that the health professionals should dress the punctured area tightly so as to avoid back flow of blood from veins. Also blood pressure and pulse has to be checked every fourth hourly and any signs or symptoms of fatigue, tachycardia, hypertension, etc has to be seriously observed with necessary resuscitative measures.
Antiplatelets, which are the drugs given to prevent coagulation are also prescribed after the procedure. Myocardial perfusion scanning is done prior to any cardiac procedures to ensure the potency and functioning of various cardiac blood vessels and cardiac tissue.