Reduction of ringing and blurring artifacts in fast spin-echo imaging.

A simple method was devised to reduce ringing and blurring artifacts caused by discontinuous T2 weighting of k-space data in fast spin-echo magnetic resonance (MR) imaging. The method demodulates the weighting function along the phase-encoding direction by using multiple T2 values derived from a set of non-phase-encoded echoes obtained from an extra excitation. The performance of this method was evaluated by computer simulations and experiments, which confirmed its capability of effectively reducing or, in some cases, even completely removing the ringing and blurring artifacts. The results also show that the proposed method produces better results than other artifact reduction methods. The method is particularly useful at high magnetic field strengths (7.1-9.4 T) and with strong gradients (> 20 G/cm) used in MR microscopy, in which the apparent T2 values are short for most tissues. The authors expect that the proposed method will find useful applications in various fast spin-echo pulse sequences.