Reduced Perfusion On Nitrate Enhanced Study Compared To Resting With 99mtc-Sestamibi Imaging For Myocardial Viability

Area of Science:

• Nuclear Medicine
• Cardiology
• Radiopharmacology

Background:

• Patients with ischemic heart disease and left ventricular dysfunction require assessment of myocardial viability.
• Myocardial perfusion imaging is a key diagnostic tool for this evaluation.

Observation:

• Two cases utilizing 99mTc-Sestamibi (99mTc-MIBI) for viability imaging with and without nitrate enhancement are presented.
• A paradoxical effect was noted, with reduced radiotracer uptake in nitrate-enhanced images compared to resting images.

Findings:

• Improvement in perfusion on nitrate-enhanced images typically indicates myocardial viability.
• In these cases, the observed reduction in uptake suggests a complex interaction beyond standard viability assessment.
• Technical factors were ruled out as the cause of the paradoxical findings.

Implications:

• The paradoxical reduction may be attributed to differential effects of oral glyceryl trinitrate (GTN) on normal versus diseased coronary vessels.
• This highlights the need to consider pharmacological effects on perfusion imaging interpretation.
• Further research is warranted to elucidate the mechanisms behind this observed phenomenon in myocardial viability studies.