Pseudo-continuous arterial spin labeling at 7 T for human brain: Estimation and correction for off-resonance effects using a Prescan

Pseudo‐continuous arterial spin labeling (ASL) can provide best signal‐to‐noise ratio efficiency with a sufficiently long tag at high fields such as 7 T, but it is very sensitive to off‐resonance fields at the tagging location. Here, a robust Prescan procedure is demonstrated to estimate the pseudo‐continuous ASL radiofrequency phase and gradients parameters required to compensate the off‐resonance effects at each vessel location. The Prescan is completed in 1–2 min and is based on acquisition of label/control pair‐wise ASL data as a function of the radiofrequency phase increment applied to the pseudo‐continuous ASL train. It is shown that this approach can be used to acquire high quality whole‐brain pseudo‐continuous ASL perfusion data of the human brain at 7 T. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.