title: Automated removal of spurious intermediate cerebral blood flow volumes improves image quality among older patients: A clinical arterial spin labeling investigation.
abstract: OBJECTIVE
  To evaluate the impact of rejecting intermediate cerebral blood flow (CBF) images that are adversely affected by head motion during an arterial spin labeling (ASL) acquisition.
  
  
  METHODS
  Eighty participants were recruited, representing a wide age range (14-90 years) and heterogeneous cerebrovascular health conditions including bipolar disorder, chronic stroke, and moderate to severe white matter hyperintensities of presumed vascular origin. Pseudocontinuous ASL and T1 -weigthed anatomical images were acquired on a 3T scanner. ASL intermediate CBF images were included based on their contribution to the mean estimate, with the goal to maximize CBF detectability in gray matter (GM). Simulations were conducted to evaluate the performance of the proposed optimization procedure relative to other ASL postprocessing approaches. Clinical CBF images were also assessed visually by two experienced neuroradiologists.
  
  
  RESULTS
  Optimized CBF images (CBFopt ) had significantly greater agreement with a synthetic ground truth CBF image and greater CBF detectability relative to the other ASL analysis methods (P < 0.05). Moreover, empirical CBFopt images showed a significantly improved signal-to-noise ratio relative to CBF images obtained from other postprocessing approaches (mean: 12.6%; range 1% to 56%; P < 0.001), and this improvement was age-dependent (P = 0.03). Differences between CBF images from different analysis procedures were not perceptible by visual inspection, while there was a moderate agreement between the ratings (κ = 0.44, P < 0.001).
  
  
  CONCLUSIONS
  This study developed an automated head motion threshold-free procedure to improve the detection of CBF in GM. The improvement in CBF image quality was larger when considering older participants.
authors: Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.|HSF Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, Ontario, Canada.
authors: Zahra
authors: Z
authors: Shirzadi
authors: HSF Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, Ontario, Canada.
authors: David E
authors: DE
authors: Crane
authors: HSF Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, Ontario, Canada.
authors: Andrew D
authors: AD
authors: Robertson
authors: Brain Sciences Research Program, Sunnybrook Research Institute, Toronto, Ontario, Canada.|Division of Neuroradiology, Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada.
authors: Pejman J
authors: http://orcid.org/0000-0001-9975-4379
authors: PJ
authors: Maralani
authors: Brain Sciences Research Program, Sunnybrook Research Institute, Toronto, Ontario, Canada.|Division of Neuroradiology, Department of Medical Imaging, University of Toronto, Toronto, Ontario, Canada.
authors: Richard I
authors: RI
authors: Aviv
authors: Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, UK.|Oxford Centre for Functional MRI of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
authors: Michael A
authors: MA
authors: Chappell
authors: HSF Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, Ontario, Canada.|Brain Sciences Research Program, Sunnybrook Research Institute, Toronto, Ontario, Canada.|Departments of Psychiatry and Pharmacology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
authors: Benjamin I
authors: BI
authors: Goldstein
authors: HSF Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, Ontario, Canada.|Brain Sciences Research Program, Sunnybrook Research Institute, Toronto, Ontario, Canada.|Division of Neurology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
authors: Sandra E
authors: SE
authors: Black
authors: Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.|HSF Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, Ontario, Canada.|Brain Sciences Research Program, Sunnybrook Research Institute, Toronto, Ontario, Canada.
authors: Bradley J
authors: BJ
authors: MacIntosh
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001714:Bipolar Disorder / Q000503:physiopathology*; D001921:Brain / Q000098:blood supply / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D002561:Cerebrovascular Disorders / Q000503:physiopathology*; D002908:Chronic Disease; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D059629:Signal-To-Noise Ratio; D013113:Spin Labels; D020521:Stroke / Q000503:physiopathology; D055815:Young Adult
chemical_list: D013113:Spin Labels
keywords: arterial spin labeling; cerebral blood flow; detectability; head motion; signal-to-noise ratio