A straightforward approach for 3D single-shot arterial spin labeling-based brain perfusion imaging: Preventing artifacts due to signal fluctuations.

Abstract

Purpose: The present work aims to evaluate the performance of three-dimensional (3D) single-shot stack-of-spirals turbo FLASH (SOS-TFL) acquisition for pseudo-continuous arterial spin labeling (PCASL) and velocity-selective ASL (VSASL)-based cerebral blood flow (CBF) mapping, as well as VSASL-based cerebral blood volume (CBV) mapping.

Methods: Digital phantom simulations were conducted for both multishot echo planar imaging and spiral trajectories with intershot signal fluctuations. PCASL-derived CBF (PCASL-CBF), VSASL-derived CBF (VSASL-CBF), and CBV (VSASL-CBV) were all acquired using 3D multishot gradient and spin-echo and SOS-TFL acquisitions following background suppression. Both simulation and in vivo images were compared between multishot and single-shot compressed sensing-regularized sensitivity encoding (CS-SENSE) reconstructions.

Results: Artifacts were observed in both simulated multishot echo planar imaging and spiral readouts, as well as in in vivo multishot ASL perfusion images. A high correlation was found between the levels of signal fluctuations among interleaves and the severity of artifacts in both simulated and in vivo data. Image artifacts were more apparent in the inferior region of the brain, especially in CBF scans. These artifacts were effectively eliminated when single-shot CS-SENSE reconstruction was applied to the same data set.

Conclusion: ASL images obtained from 3D segmented gradient and spin-echo or SOS-TFL acquisitions can exhibit artifacts caused by signal fluctuations among different shots, which persist even after the application of background suppression pulses. In contrast, these artifacts were prevented when single-shot CS-SENSE reconstruction was applied to the same SOS-TFL data set.