Маркери перфузії міокарда з технецієм-99m (Tc-99)

Tc-99m sestamibi

Myocardial uptake is slower than that with thallium, but there is little myocardial washout, allowing timing flexibility; patients with acute symptoms can be injected with sestamibi immediately and imaged several hours later.

Uptake depends more on blood flow than on viable myocardium; viable regions with low blood flow may be misclassified as scar.

Studies may be done on a single or on separate days, with a low initial dose during stress followed by a much higher dose at rest.

With electrocardiography (ECG)-gated imaging, ventricular wall motion, wall thickening, and ejection fraction can be estimated.

Tc-99m tetrofosmin

Characteristics are similar to those of sestamibi.

Tc-99m teboroxime

First-pass extraction from the myocardium is high, with rapid washout; half of peak myocardial activity is gone by 10 minutes.

Because of its rapid dynamics, use with treadmill exercise is difficult.

Studies suggest that stress-redistribution testing may be completed within 15 minutes of pharmacologic stress. Coronary artery disease may be detectable by analyzing myocardial washout of the tracer after injection at rest without the need for stress.