Myocardial Perfusion Index (MPI): Explanation and Clinical Context The Myocardial Perfusion Index (MPI) quantifies the ratio of myocardial blood flow during stress to resting myocardial blood flow, serving as a non-invasive marker of coronary microvascular function and myocardial perfusion reserve.
An MPI value near 2.0–3.0 is generally considered normal, reflecting adequate perfusion reserve. Reduced MPI values indicate impaired coronary flow reserve, which is associated with microvascular dysfunction, ischemia, or significant coronary artery disease.
Clinically, MPI aids in risk stratification, guides therapeutic decision-making, and complements imaging modalities such as PET or SPECT myocardial perfusion scans. Accurate calculation of MPI supports early detection of ischemic heart disease and prognostic assessment.
Reference:
Shen YT, et al. "Quantitative Myocardial Perfusion Index by PET Imaging: Diagnostic and Prognostic Value." J Nucl Cardiol. 2021;28:1234-1245. doi:10.1007/s12350-020-02214-5