Overview of cardiovascular nuclear magnetic resonance imaging

Application of NMR technology to the evaluation of the cardiovascular system is still in its infancy. NMR can frequently yield information equivalent to echocardiography or angiography but cost, long imaging times, and lack of portability have discouraged widespread use. To date, NMR has not replaced standard imaging modalities in the evaluation of most cardiovascular disease states, although it appears to have a unique role in the delineation of great vessel pathology, the evaluation of congenital heart disease, and the delineation of cardiac and paracardiac masses. Appearance of tissue and flowing blood and contrast between structures are highly dependent on magnetic field strength and the imaging pulse sequence used. Published comparisons between NMR and other imaging modalities have to be interpreted and extrapolated with caution, and sensitivity and specificity of NMR imaging in different disease entities should be further validated. With technological improvements, shortening of examination times and data processing times and true three-dimensional imaging may be possible in the near future. Ultimately, however, the clinical importance of NMR will depend on the development of unique applications such as examination of regional cardiac metabolism, noninvasive coronary and peripheral angiography, myocardial perfusion imaging, and improved tissue characterization.