[Evaluation of three-dimensional contrast-enhanced MRA using differential rate k-space sampling (DRKS)]

The progress of three-dimensional (3D) magnetic resonance angiography used in combination with contrast medium (CE-MRA) has been remarkable. Currently, angiography aims at improvements in time resolution without sacrificing spatial resolution. We conducted a basic study of 3D differential rate k-space sampling (DRKS) in which the slice direction of the k-space is divided into two or more areas, the echo data near zero encoding is sampled by a higher time resolution than data in other areas, and reconstruction is done within a short time. This technique involved a problem in which ghost artifacts occur easily when the concentration of contrast medium changes extremely or when signal intensity changes suddenly. This is probably due to a difference in the time to sample data between the low- and high-frequency areas. When we used DRKS to grasp these characteristics, however, it was useful because it allowed reconstruction with an extremely high time resolution.