CMR—basic principles

Cardiac magnetic resonance imaging (CMR) has rapidly evolved to become the modality of choice in the evaluation of a wide spectrum of cardiovascular disorders. This is mostly related to its multiparametric approach where the different features such as morphology (including deep tissue characterization), function, perfusion can be non-invasively studied using a series of (different) pulse sequences. Therefore, CMR may provide a ‘one stop shop’ approach to cardiac patients offering a complete cardiac evaluation by a single modality without the use of ionizing radiation. However, to maximize its clinical use, not all pulse sequences should be used in every patient. Moreover, minimizing time spent in the magnetic resonance imaging (MRI) machine is desirable in critically ill, unstable patients. Therefore, experienced cardiac imagers from radiology and cardiology should be present to provide on-site real-time assessment of the images and to determine which pulse sequences are necessary each patient. In this fashion, a complete CMR exam should be obtainable in less than 30 minutes for the vast majority of patients. The aim of this chapter is to describe the physics and practical aspects of CMR and then explore the available pulse sequences, so that the clinical utility of CMR can be maximized.