Tools for cardiovascular magnetic resonance imaging

In less than fifteen years, as a non-invasive imaging option, cardiovascular MR has grown from a being a mere curiosity to becoming a widely used clinical tool for evaluating cardiovascular disease. Cardiovascular magnetic resonance imaging (CMRI) is now routinely used to study myocardial structure, cardiac function, macro vascular blood flow, myocardial perfusion, and myocardial viability. For someone entering the field of cardiac MR, this rapid pace of development in the field of CMRI might make it difficult to identify a cohesive starting point. In this brief review, we have attempted to summarize the key cardiovascular imaging techniques that have found widespread clinical acceptance. In particular, we describe the essential cardiac and respiratory gating techniques that form the backbone of all cardiovascular imaging methods. It is followed by four sections that discuss: (I) the gradient echo techniques that are used to assess ventricular function; (II) black-blood turbo spin echo (SE) methods used for morphologic assessment of the heart; (III) phase-contrast based techniques for the assessment of blood flow; and (IV) CMR methods for the assessment of myocardial ischemia and viability. In each section, we briefly summarize technical considerations relevant to the clinical use of these techniques, followed by practical information for its clinical implementation. In each of those four areas, CMRI is considered either as the benchmark imaging modality against which the diagnostic performance of other imaging modalities are compared against, or provides a complementary capability to existing imaging techniques. We have deliberately avoided including cutting-edge CMR imaging techniques practiced at few academic centers, and restricted our discussion to methods that are widely used and are likely to be available in a clinical setting. Our hope is that this review would propel an interested reader toward more comprehensive reviews in the literature.