PULMONARY VASCULATURE - SINGLE BREATH-HOLD MR IMAGING WITH PHASED-ARRAY COILS

The authors obtained magnetic resonance images of the pulmonary vasculature with reduced artifacts caused by cardiac and respiratory motion by acquiring a series of moderately thin sections in a single breath-hold with an ultrafast gradient-echo pulse sequence. The series of two-dimensional images was postprocessed with a maximum-intensity projection algorithm. Time-of-flight inflow enhancement increased the signal intensity of arteries and veins while radiofrequency phase spoiling produced limited stationary spin suppression of the chest wall. Moderately thin (8-mm) section thicknesses were used to attain the resolution necessary to visualize smaller pulmonary vascular segments up to the chest wall while the number of acquired sections was minimized. Because the body coil did not provide an adequate signal-to-noise ratio (S/N) for a single excitation and thin-section acquisitions, phased-array coils covering either the right or left lung were used to improve the S/N. The use of single breath-holds prevented the misregistration and blurring that occurred in examinations performed with multiple breath-holds.