Seeing Beyond Scar: The Role of MPI and PET in Identifying Viable Myocardium

Abstract

Myocardial perfusion imaging (MPI) is a non-invasive functional technique used to assess myocardial blood flow and evaluate coronary artery disease (CAD). By comparing perfusion under stress (exercise or pharmacologic) and rest conditions, MPI enables differentiation between reversible ischemia and irreversible infarction, while also aiding in risk stratification and prognostication for revascularization. At NINMAS, MPI has been routinely performed since 2004 using a one-day stress–rest protocol with Tc-99m sestamibi.

However, regions of infarcted myocardium may still contain viable, metabolically active (hibernating) tissue that can recover function following revascularization. To assess this, cardiac PET metabolic imaging with 18F-FDG was introduced at NINMAS in 2019 and has since been performed routinely, with approximately 80 patients studied to date.

The integration of cardiac PET with conventional MPI has significantly enhanced the evaluation of myocardial viability by distinguishing viable from non-viable tissue more accurately. This advancement supports more informed clinical decision-making, particularly in selecting patients who would benefit from revascularization. Consequently, it helps avoid unnecessary surgical interventions, reducing associated risks and economic burden.

This study highlights the current status of MPI and the evolving role of cardiac PET imaging in myocardial viability assessment at NINMAS.

Bangladesh J Medicine 2026; Vol. 37, No. 2(1): pp. 215.