Which test uses a radioactive tracer to evaluate myocardial perfusion during stress?

Which test uses a radioactive tracer to evaluate myocardial perfusion during stress?

• A. Dobutamine stress echocardiography
• B. Thallium stress test
• C. Nuclear perfusion scan
• D. Cardiac MRI

Answer: (B)

Evaluating blood flow to the heart muscle under stress with a radioactive tracer is a nuclear perfusion imaging approach. In a thallium stress test, a small amount of thallium-201 is injected while the heart is under stress (through exercise or medications). Thallium behaves like potassium and is taken up by healthy heart tissue proportional to blood flow. Images captured with a gamma camera (often as SPECT) show how well the heart is perfused: areas that receive less blood during stress appear as defects, indicating possible ischemia. Comparing stressed images to rest images helps distinguish reversible ischemia from scar tissue. Dobutamine stress echocardiography uses heart-wall motion changes observed with ultrasound, not a radioactive tracer. A nuclear perfusion scan is a broader term for imaging with a radiotracer, which can include a thallium study or other tracers, but the classic test name that matches this description is the thallium stress test. Cardiac MRI uses magnetic resonance and does not involve ionizing radiation or radioactive tracers.

Evaluating blood flow to the heart muscle under stress with a radioactive tracer is a nuclear perfusion imaging approach. In a thallium stress test, a small amount of thallium-201 is injected while the heart is under stress (through exercise or medications). Thallium behaves like potassium and is taken up by healthy heart tissue proportional to blood flow. Images captured with a gamma camera (often as SPECT) show how well the heart is perfused: areas that receive less blood during stress appear as defects, indicating possible ischemia. Comparing stressed images to rest images helps distinguish reversible ischemia from scar tissue.

Dobutamine stress echocardiography uses heart-wall motion changes observed with ultrasound, not a radioactive tracer. A nuclear perfusion scan is a broader term for imaging with a radiotracer, which can include a thallium study or other tracers, but the classic test name that matches this description is the thallium stress test. Cardiac MRI uses magnetic resonance and does not involve ionizing radiation or radioactive tracers.