title: Partial volume correction in arterial spin labeling using a Look-Locker sequence.
abstract: OBJECTIVE
  Partial volume (PV) effects are caused by limited spatial resolution and significantly affect cerebral blood flow investigations with arterial spin labeling. Therefore, accurate PV correction (PVC) procedures are required. PVC is commonly based on PV maps obtained from segmented high-resolution T1 -weighted images. Segmentation of these images is error-prone, and it can be difficult to coregister these images accurately with the single-shot ASL images such as those created by echo-planar imaging (EPI). In this paper, an alternative method for PV map generation is proposed.
  
  
  METHODS
  The Look-Locker EPI (LL-EPI) acquisition is used for analyzing the T1 -recovery curve and for subsequent PV map generation. The new method was evaluated in five healthy volunteers (mean age 30 ± 3.7 years).
  
  
  RESULTS
  By applying a linear regression method for PVC, a 12% decrease in regression error was reached with the new method.
  
  
  CONCLUSIONS
  PV maps extraction from LL-EPI is a viable, possibly superior alternative to the standard approach based on segmentation of high-resolution T1 -weighted images.
authors.affiliation: PET Center, Institute of Radiopharmacy, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Petr
authors.forename: Georg
authors.initials: G
authors.lastname: Schramm
authors.forename: Frank
authors.initials: F
authors.lastname: Hofheinz
authors.forename: Jens
authors.initials: J
authors.lastname: Langner
authors.forename: Jörg
authors.initials: J
authors.lastname: van den Hoff
mesh_terms: D000328:Adult; D000465:Algorithms; D016477:Artifacts; D001783:Blood Flow Velocity / Q000502:physiology; D002536:Cerebral Arteries / Q000033:anatomy & histology / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D013113:Spin Labels
chemical_list: D013113:Spin Labels
keywords: ASL; arterial spin labeling; cerebral blood flow; look-locker; partial volume effect