title: Arterial spin labeling with simultaneous multi-slice echo planar imaging.
abstract: OBJECTIVE
  Simultaneous multi-slice (SMS) echo planar imaging (EPI) is incorporated into two-dimensional (2D) arterial spin labeling (ASL) imaging to produce more slices for measuring perfusion in a larger region of the brain than currently possible with multi-slice EPI.
  
  
  METHODS
  Pulsed ASL (PASL) preparations using FAIR and QUIPSS II techniques were combined with SMS-EPI. Testing was performed in four subjects at 3 Tesla. Multiband slice acceleration factors (MB) from MB-2 to MB-5 using 40 averages were evaluated. Comparisons were made quantitatively to PASL 2D EPI and qualitatively to PASL 3D GRASE.
  
  
  RESULTS
  In the 12 slice data set, spatial SNR for the perfusion weighted images averaged across subjects was 3.28 and 3.44 for the two sequential MB-1 acquisitions as control comparison, 3.25 for MB-2 and 2.98 for MB-3. The temporal SNR averaged 1.01 and 0.99 for MB-1, 0.89 for MB-2, and 0.78 for MB-3. For whole-brain spatial coverage, the 20 slice data sets could be acquired in narrower time windows, from 874 ms using EPI (MB-1) down to 196 ms using MB-5. SMS-EPI ASL differed from 3D GRASE ASL, which can use background suppression and has less susceptibility artifact as a CPMG SE sequence.
  
  
  CONCLUSIONS
  SMS-EPI has a major advantage over EPI-based ASL imaging by increasing slice coverage without lengthening the acquisition time window.
authors.affiliation: Helen Wills Institute of Neuroscience, University of California, Berkeley, Advanced MRI Technologies, Sebastopol, California, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Feinberg
authors.forename: Alexander
authors.initials: A
authors.lastname: Beckett
authors.forename: Liyong
authors.initials: L
authors.lastname: Chen
mesh_terms: D000465:Algorithms; D001783:Blood Flow Velocity / Q000502:physiology; D002536:Cerebral Arteries / Q000033:anatomy & histology* / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D017352:Echo-Planar Imaging / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: ASL; EPI; GRASE; PASL; multiband; simultaneous