1Dept. of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; 2Neurimage Nord, Hamburg-Kiel-Lbeck, Germany
Echo-planar imaging suffers from geometric distortions in the presence of eddy currents which in particular are prominent after applying diffusion-weighting gradient pulses. To reduce these eddy currents, a double-spin-echo preparation is commonly used where the four pulse durations are adjusted to null eddy currents of a given time constant. However, eddy currents with different time constants are usually present yielding residual geometric distortions. It is shown that these residual distortions can be reduced when adjusting the two gradient pairs to different time constants. Although none of the time constants is compensated completely, the overall eddy-current performance can be improved.