Primer on cardiac magnetic resonance imaging: how to perform the examination

Cardiac magnetic resonance imaging is made possible by utilizing an external signal, the patient's own electrocardiogram, to time image acquisition. ECG gated cardiac magnetic resonance examination may be performed using spin-echo or gradient reversal techniques or their newer k-space segmented variants. Spin-echo techniques provide the highest contrast between rapidly moving blood and the cardiac chambers and arteries and veins containing the blood, but are of relatively low temporal resolution. Gradient reversal acquisition, however, provides higher temporal resolution ideal for evaluating changes in myocardial thickening, ventricular wall motion abnormalities, and changes in chamber volume through the cardiac cycle; gradient reversal technique has significantly lower contrast resolution. Careful attention to the details of image acquisition will provide high-quality images of the heart and great arteries from which important morphologic and physiological information may be obtained, aiding in the diagnosis and management of patients with cardiovascular disease.