title: Arterial spin labeling-based Z-maps have high specificity and positive predictive value for neurodegenerative dementia compared to FDG-PET.
abstract: OBJECTIVE
  Cerebral perfusion analysis based on arterial spin labeling (ASL) MRI has been proposed as an alternative to FDG-PET in patients with neurodegenerative disease. Z-maps show normal distribution values relating an image to a database of controls. They are routinely used for FDG-PET to demonstrate disease-specific patterns of hypometabolism at the individual level. This study aimed to compare the performance of Z-maps based on ASL to FDG-PET.
  
  
  METHODS
  Data were combined from two separate sites, each cohort consisting of patients with Alzheimer's disease (n = 18 + 7), frontotemporal dementia (n = 12 + 8) and controls (n = 9 + 29). Subjects underwent pseudocontinuous ASL and FDG-PET. Z-maps were created for each subject and modality. Four experienced physicians visually assessed the 166 Z-maps in random order, blinded to modality and diagnosis.
  
  
  RESULTS
  Discrimination of patients versus controls using ASL-based Z-maps yielded high specificity (84%) and positive predictive value (80%), but significantly lower sensitivity compared to FDG-PET-based Z-maps (53% vs. 96%, p < 0.001). Among true-positive cases, correct diagnoses were made in 76% (ASL) and 84% (FDG-PET) (p = 0.168).
  
  
  CONCLUSIONS
  ASL-based Z-maps can be used for visual assessment of neurodegenerative dementia with high specificity and positive predictive value, but with inferior sensitivity compared to FDG-PET.
  
  
  CONCLUSIONS
  • ASL-based Z-maps yielded high specificity and positive predictive value in neurodegenerative dementia. • ASL-based Z-maps had significantly lower sensitivity compared to FDG-PET-based Z-maps. • FDG-PET might be reserved for ASL-negative cases where clinical suspicion persists. • Findings were similar at two study sites.
authors.affiliation: Department of Surgical Sciences, Radiology, Uppsala University, Uppsala, Sweden. david.fallmar@radiol.uu.se.
authors.forename: David
authors.initials: D
authors.lastname: Fällmar
authors.affiliation: Department of Surgical Sciences, Radiology, Uppsala University, Uppsala, Sweden.|Department of Neuroradiology, University Medical Center Freiburg, Freiburg, Germany.|Faculty of Medicine, University of Geneva, Geneva, Switzerland.|Affidea CDRC - Centre Diagnostique Radiologique de Carouge, Carouge, Switzerland.
authors.forename: Sven
authors.initials: S
authors.lastname: Haller
authors.affiliation: Department of Surgical Sciences, Nuclear Medicine and PET, Uppsala University, Uppsala, Sweden.|Hermes Medical Solutions, Stockholm, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Lilja
authors.affiliation: Department of Surgical Sciences, Nuclear Medicine and PET, Uppsala University, Uppsala, Sweden.
authors.forename: Torsten
authors.initials: T
authors.lastname: Danfors
authors.affiliation: Department of Public Health and Caring Sciences, Geriatrics, Uppsala University, Uppsala, Sweden.
authors.forename: Lena
authors.initials: L
authors.lastname: Kilander
authors.affiliation: Department of Radiology and Nuclear Medicine, VU University Medical Center, Neuroscience Campus, Amsterdam, The Netherlands.
authors.forename: Nelleke
authors.initials: N
authors.lastname: Tolboom
authors.affiliation: Department of Neuroradiology, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: Karl
authors.initials: K
authors.lastname: Egger
authors.affiliation: Department of Radiology, Medical Physics, Faculty of Medicine, Medical Center University of Freiburg, Freiburg, Germany.
authors.forename: Elias
authors.initials: E
authors.lastname: Kellner
authors.affiliation: Department of Radiology and Nuclear Medicine, VU University Medical Center, Neuroscience Campus, Amsterdam, The Netherlands.
authors.forename: Philip M
authors.initials: PM
authors.lastname: Croon
authors.affiliation: Department of Neurology, Alzheimer Center Amsterdam, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Sander C J
authors.initials: SCJ
authors.lastname: Verfaillie
authors.affiliation: Department of Radiology and Nuclear Medicine, VU University Medical Center, Neuroscience Campus, Amsterdam, The Netherlands.
authors.forename: Bart N M
authors.initials: BNM
authors.lastname: van Berckel
authors.affiliation: Department of Neurology, Alzheimer Center Amsterdam, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Rik
authors.initials: R
authors.lastname: Ossenkoppele
authors.affiliation: Department of Radiology and Nuclear Medicine, VU University Medical Center, Neuroscience Campus, Amsterdam, The Netherlands.|Institutes of Neurology and Healthcare Engineering, UCL, London, UK.
authors.forename: Frederik
authors.initials: F
authors.lastname: Barkhof
authors.affiliation: Department of Surgical Sciences, Radiology, Uppsala University, Uppsala, Sweden.
authors.forename: Elna-Marie
authors.initials: EM
authors.lastname: Larsson
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology; D001158:Arteries; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology; D005260:Female; D019788:Fluorodeoxyglucose F18; D057180:Frontotemporal Dementia / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013113:Spin Labels
chemical_list: D013113:Spin Labels; D019788:Fluorodeoxyglucose F18
keywords: 18F-FDG; Arterial spin labeling MRI; Dementia; Neurodegenerative; Visual assessment