Perfusion imaging during a stress test is called which?

• A. Echocardiography
• B. Coronary angiography
• C. Cardiac MRI
• D. Nuclear stress test

Answer: (D)

Perfusion imaging during stress tests assesses how well blood is reaching different regions of the heart muscle when the heart is under increased demand. The technique used for this purpose is a nuclear stress test. A small amount of radioactive tracer is given at peak stress (exercise or pharmacologic), and a gamma camera images how the tracer distributes through the myocardium. Areas with less tracer uptake reveal decreased perfusion due to narrowed or blocked coronary arteries, highlighting ischemia. This approach directly visualizes blood flow, unlike stress echocardiography which evaluates how the heart muscle moves under stress, or coronary angiography which maps the coronary arteries themselves. Cardiac MRI can also perform perfusion imaging, but the common label for perfusion imaging during a stress test is a nuclear stress test.