Radionuclide ventriculography

Radionuclide ventriculography, a type of cardiac ventriculography, is a form of nuclear imaging, where a gamma camera is used to create an image following injection of radioactive material, usually Technetium-99m (^99mTc) labeled red blood cells. In radionuclide ventriculography, the radionuclide has the property of circulating through the cardiac chambers, availing for studies of the pumping function of the heart. In contrast, in myocardial perfusion imaging, the radionuclide is taken up by the myocardial cells, making its presence correlating with myocardial perfusion or viability of the cells.

Radionuclide ventriculography is done to evaluate coronary artery disease (CAD), valvular heart disease, congenital heart diseases, cardiomyopathy, and other cardiac disorders. It exposes patients to less radiation than do comparable chest x-ray studies. However, the radioactive material is retained in the patient for several days after the test, during which sophisticated radiation alarms may be triggered, such as in airports. Radionuclide ventriculography has largely been replaced by echocardiography, which is less expensive, and does not require radiation exposure. Radionuclide ventriculography gives a much more precise measurement of left ventricular ejection fraction (LVEF) than a transthoracic echocardiogram (TTE). Transthoracic echocardiogram is highly operator dependant, therefore radionuclide ventriculography is a more reproducible measurement of LVEF. Its primary use today is in monitoring cardiac function in patients receiving certain chemotherapeutic agents (anthracyclines: doxorubicin or daunorubicin) which are cardiotoxic. The chemotherapy dose is often determined by the patient's cardiac function. In this setting, a much more accurate measurement of ejection fraction, than a transthoracic echocardiogram can provide, is necessary.