Quantitative myocardial perfusion imaging across PET, SPECT, CMR, and CT.

Recent clinical trials demonstrating the prognostic value of coronary computed tomography angiography (CCTA), and the limited incremental prognostic benefit of ischemia-guided revascularization over optimal medical therapy, have shifted focus away from functional testing. Nevertheless, myocardial perfusion assessment remains essential in patients with known or suspected coronary artery disease (CAD), microvascular dysfunction, ischemia with normal coronary arteries (INOCA), coronary anomalies, and cardiomyopathies. Advances in positron emission tomography (PET), cardiovascular magnetic resonance (CMR), and computed tomography (CT) now enable absolute quantification of myocardial blood flow (MBF), providing improved diagnostic and prognostic performance and underscoring the need to reappraise myocardial perfusion imaging. This mini-review summarizes key physiological principles, contemporary acquisition and post-processing strategies, and the clinical relevance of myocardial perfusion imaging (MPI) across PET, Single Photon Emission Computed Tomography (SPECT), CMR, and CT, and discusses future perspectives in quantitative MPI.