title: Wedge-shaped slice-selective adiabatic inversion pulse for controlling temporal width of bolus in pulsed arterial spin labeling.
abstract: In pulsed arterial spin labeling (PASL) methods, arterial blood is labeled by inverting a slab with uniform thickness, resulting in different temporal widths of boluses in vessels with different flow velocities. This limits the temporal resolution and signal-to-noise ratio (SNR) efficiency gains in PASL-based methods intended for high temporal resolution and SNR efficiency, such as turbo-ASL and turbo-QUASAR.
  
  
  
  A novel wedge-shaped (WS) adiabatic inversion pulse is developed by adding in-plane gradient pulses to a slice-selective (SS) adiabatic inversion pulse to linearly modulate the inversion thicknesses at different locations while maintaining the adiabatic properties of the original pulse. A hyperbolic secant (HS)-based WS inversion pulse was implemented. Its performance was tested in simulations and in phantom and human experiments and compared with an SS HS inversion pulse.
  
  
  
  Compared with the SS inversion pulse, the WS inversion pulse was capable of inducing different inversion thicknesses at different locations. It could be adjusted to generate a uniform temporal width of boluses in arteries at locations with different flow velocities.
  
  
  
  The WS inversion pulse can be used to control the temporal widths of labeled boluses in PASL experiments. This should benefit PASL experiments by maximizing labeling duty cycle and improving temporal resolution and SNR efficiency. Magn Reson Med 76:838-847, 2016. © 2015 Wiley Periodicals, Inc.
authors.affiliation: Department of Radiology, University of California, San Diego, La Jolla, California, USA.
authors.forename: Jia
authors.initials: J
authors.lastname: Guo
authors.affiliation: Department of Radiology, University of California, San Diego, La Jolla, California, USA.
authors.forename: Richard B
authors.initials: RB
authors.lastname: Buxton
authors.affiliation: Department of Radiology, University of California, San Diego, La Jolla, California, USA.|Department of Psychiatry, University of California, San Diego, La Jolla, California, USA.
authors.forename: Eric C
authors.initials: EC
authors.lastname: Wong
mesh_terms: D000328:Adult; D000465:Algorithms; D001783:Blood Flow Velocity / Q000502:physiology*; D002533:Cerebral Angiography / Q000295:instrumentation / Q000379:methods*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003198:Computer Simulation; D003287:Contrast Media / Q000493:pharmacokinetics*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000295:instrumentation / Q000379:methods*; D008955:Models, Cardiovascular; D019047:Phantoms, Imaging; D011673:Pulsatile Flow / Q000502:physiology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D013113:Spin Labels
chemical_list: D003287:Contrast Media; D013113:Spin Labels
keywords: arterial spin labeling; pulsed ASL; slice-selective adiabatic inversion; temporal width of bolus; wedge-shaped adiabatic inversion