MR myocardial perfusion imaging: insights on techniques, analysis, interpretation, and findings.

Coronary microcirculatory dysfunction has a fundamental role in the pathophysiology of ischemic coronary artery disease (CAD) as well as various other cardiovascular disorders. Invasive coronary angiography remains the standard of reference for diagnosis of CAD. Nevertheless, it has been well acknowledged that the degree of luminal narrowing of epicardial coronary lesions detected at angiography is a poor predictor of the functional severity of the lesion. Recent studies demonstrate that assessment of coronary microcirculatory function by means of noninvasive myocardial perfusion imaging helps increase diagnostic accuracy and guide medical decision-making. Among available diagnostic modalities, cardiac magnetic resonance (MR) perfusion imaging has evolved to become a reliable and robust tool providing accurate quantitative assessment of regional myocardial perfusion. Owing to its high spatial resolution, noninvasive nature, and absence of ionizing radiation, cardiac MR perfusion imaging has improved detection of clinically relevant CAD. It has also offered further insights into the understanding of various cardiovascular disorders resulting from coronary microvascular dysfunction in the absence of proximal flow-limiting CAD. Cardiac MR perfusion imaging is now routinely used in many centers and shows promise in evaluating patients with disorders beyond those of the epicardial coronary circulation. Recent implementation of high-field-strength magnets and rapid acquisition techniques have further contributed to expanding the role of cardiac MR perfusion imaging to include novel promising applications. In this article, we provide an overview of cardiac MR perfusion imaging, including techniques, image analysis, and clinical applications.