Absolute PET Myocardial Blood Flow Quantification in the Diagnosis and Risk Stratification of Coronary Microvascular Dysfunction

Invasive coronary angiography reveals non-obstructive coronary artery disease in approximately 60% of patients. Meanwhile, up to two-thirds of these individuals have coronary microvascular dysfunction (CMD), which often explains their symptoms. CMD is a clinically important condition that affects women with chronic coronary syndrome much more often than men. In these patients, impaired myocardial flow reserve (MFR) is a reliable predictor of adverse clinical outcomes, even in the absence of visible perfusion defects. Positron emission tomography (PET) enables quantification of myocardial blood flow (MBF) and MFR, both of which play critical roles in the diagnosis of CMD, support accurate risk stratification, and may be useful for monitoring treatment response. Emerging radiotracers, such as 18F-flurpiridaz, offer favorable pharmacokinetics and practical logistical benefits, thereby improving clinical access to PET imaging. Parallel advances, including artificial intelligence-powered analytical tools and total-body PET, are expected to enhance reproducibility and efficiency, further integrating myocardial flow assessment into routine clinical workflows. As technology and evidence continue to evolve, PET-based MBF quantification is likely to become an essential tool in precision cardiovascular care, effectively closing the gap between physiology and clinical decision-making. This narrative review aims to provide an overview of coronary microvascular pathophysiology and the most up-to-date evidence regarding the use of PET-derived MBF quantification in the diagnosis and management of patients with CMD.