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Keywords:

  • velocity-selective ASL;
  • arterial spin labeling;
  • perfusion;
  • eddy currents

Abstract

Velocity-selective (VS) arterial spin labeling is a promising method for measuring perfusion in areas of slow or collateral flow by eliminating the bolus arrival delay associated with other spin labeling techniques. However, B0 and B1 inhomogeneities and eddy currents during the VS preparation hinder accurate quantification of perfusion with VS arterial spin labeling. In this study, it is demonstrated through simulations and experiments in healthy volunteers that eddy currents cause erroneous tagging of static tissue. Consequently, mean gray matter perfusion is overestimated by up to a factor of 2, depending on the VS preparation used. A novel eight-segment B1 insensitive rotation VS preparation is proposed to reduce eddy current effects while maintaining the B0 and B1 insensitivity of previous preparations. Compared to two previous VS preparations, the eight-segment B1 insensitive rotation is the most robust to eddy currents and should improve the quality and reliability of VS arterial spin labeling measurements in future studies. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.