99mTc-sestamibi: its clinical role as a viability agent

Area of Science:

• Nuclear cardiology
• Cardiovascular imaging

Background:

• The relationship between viable myocardium and 99mTc-sestamibi uptake requires further definition.
• Preliminary data suggest reduced uptake isn't always scar, and it correlates with coronary stenosis severity.

Purpose of the Study:

• To define the relationship between rest thallium-201 and 99mTc-sestamibi uptake in dyssynergic segments.
• To evaluate 99mTc-sestamibi as a viability agent in patients with ventricular dysfunction.

Main Methods:

• Studied 10 patients with ventricular dysfunction.
• Compared rest thallium-201 and 99mTc-sestamibi uptake in myocardial segments.
• Assessed post-revascularization regional wall motion and predictive accuracy.

Main Results:

• 99mTc-sestamibi uptake was higher in normal segments than thallium-201.
• Uptake was reduced similarly in segments with stenotic arteries, regardless of wall motion abnormalities.
• 99mTc-sestamibi had lower positive (88%) and negative (69%) predictive accuracy for viability than thallium-201 post-revascularization.

Conclusions:

• 99mTc-sestamibi is a sensitive perfusion agent for detecting resting blood flow reduction.
• It can be cautiously used as a viability agent in segments with wall motion abnormalities.
• Thallium-201 remains superior for assessing myocardial viability in these contexts.