title: Reproducibility of pharmacological ASL using sequences from different vendors: implications for multicenter drug studies.
abstract: OBJECTIVE
  The current study assesses the multicenter feasibility of pharmacological arterial spin labeling (ASL) by comparing a caffeine-induced relative cerebral blood flow decrease (%CBF↓) measured with two pseudo-continuous ASL sequences as provided by two major vendors.
  
  
  METHODS
  Twenty-two healthy volunteers were scanned twice with both a 3D spiral (GE) and a 2D EPI (Philips) sequence. The inter-session reproducibility was evaluated by comparisons of the mean and within-subject coefficient of variability (wsCV) of the %CBF↓, both for the total cerebral gray matter and on a voxel level.
  
  
  RESULTS
  The %CBF↓ was larger when measured with the 3D spiral sequence (23.9 ± 5.9 %) than when measured with the 2D EPI sequence (19.2 ± 5.6 %) on a total gray matter level (p = 0.02), and on a voxel level in the posterior watershed area (p < 0.001). There was no difference between the gray matter wsCV of the 3D spiral (57.3 %) and 2D EPI sequence (66.7 %, p = 0.3), whereas on a voxel level, the wsCV was visibly different between the sequences.
  
  
  CONCLUSIONS
  The observed differences between ASL sequences of both vendors can be explained by differences in the employed readout modules. These differences may seriously hamper multicenter pharmacological ASL, which strongly encourages standardization of ASL implementations.
authors.affiliation: Department of Radiology, G1-230, Academic Medical Center, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. henkjanmutsaerts@gmail.com.
authors.forename: Henri J M M
authors.initials: HJ
authors.lastname: Mutsaerts
authors.affiliation: Department of Radiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: Rebecca M E
authors.initials: RM
authors.lastname: Steketee
authors.affiliation: Department of Radiology, G1-230, Academic Medical Center, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
authors.forename: Dennis F R
authors.initials: DF
authors.lastname: Heijtel
authors.affiliation: Department of Physics and Medical Technology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Joost P A
authors.initials: JP
authors.lastname: Kuijer
authors.affiliation: Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Matthijs J P
authors.initials: MJ
authors.lastname: van Osch
authors.affiliation: Department of Radiology, G1-230, Academic Medical Center, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
authors.forename: Charles B L M
authors.initials: CB
authors.lastname: Majoie
authors.affiliation: Department of Radiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: Marion
authors.initials: M
authors.lastname: Smits
authors.affiliation: Department of Radiology, G1-230, Academic Medical Center, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
authors.forename: Aart J
authors.initials: AJ
authors.lastname: Nederveen
mesh_terms: D001921:Brain / Q000187:drug effects / Q000502:physiology*; D002110:Caffeine / Q000008:administration & dosage*; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004341:Drug Evaluation / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation* / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000295:instrumentation* / Q000379:methods; D008297:Male; D015337:Multicenter Studies as Topic / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013113:Spin Labels
chemical_list: D013113:Spin Labels; D002110:Caffeine
keywords: Magnetic resonance imaging; Multicenter studies as topic; Perfusion; Pharmacological biomarkers; Reproducibility of results