Pseudo-continuous arterial spin labeling (pcASL) at 7T suffers from insufficient B1+-amplitudes and specific absorption rate (SAR) constraints. Even with B1+ phase-only or phase/amplitude shimming for the labeling the resulting inversion is suboptimal. In this work, we performed Bloch simulations to examine the impact of thicker pcASL labeling slices by adjusting the slice-selective gradient of a B1+-shimmed labeling train exploiting Variable-Rate Selective Excitation. The findings were evaluated experimentally in 5 healthy volunteers. Using lower slice-selective gradients and subsequently longer exposure of the spins to the pcASL labeling train, the perfusion images improved according to gray matter temporal signal-to-noise ratio by 35%.
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