Semi-quantitative Evaluation of Myocardial Viability in Manganese-Enhanced MRI: A Rat Heart Transplant Model Study

Motivation: Manganese enhanced MRI has shown promise in differentiating viable from non-viable myocardium, yet its potential for assessing the level of myocardial viability is unexplored. Goal(s): To evaluate whether MEMRI can detect viability differences in rat heart transplant models through dynamic imaging of manganese uptake. Approach: Rat hearts were transplanted either immediately or after 18-hour preservation. MEMRI was performed at three phases post-injection to calculate signal intensity ratios (SIR) in myocardial tissue, comparing changes over time between groups. Results: SIR analysis revealed significant viability-dependent enhancement differences, particularly in late-phase imaging, supporting MEMRI's role in early myocardial viability assessment for transplantation. Impact: This study demonstrates that an increase in signal intensity ratio reflects the level of myocardial viability and highlights MEMRI's potential for assessing myocardial viability in transplant models. This semi-quantitative approach could enhance clinical evaluations of myocardial viability.