title: Analysis of the effects of noise, DWI sampling, and value of assumed parameters in diffusion MRI models.
abstract: This study was a systematic evaluation across different and prominent diffusion MRI models to better understand the ways in which scalar metrics are influenced by experimental factors, including experimental design (diffusion-weighted imaging [DWI] sampling) and noise.
  
  
  
  Four diffusion MRI models-diffusion tensor imaging (DTI), diffusion kurtosis imaging (DKI), mean apparent propagator MRI (MAP-MRI), and neurite orientation dispersion and density imaging (NODDI)-were evaluated by comparing maps and histogram values of the scalar metrics generated using DWI datasets obtained in fixed mouse brain with different noise levels and DWI sampling complexity. Additionally, models were fit with different input parameters or constraints to examine the consequences of model fitting procedures.
  
  
  
  Experimental factors affected all models and metrics to varying degrees. Model complexity influenced sensitivity to DWI sampling and noise, especially for metrics reporting non-Gaussian information. DKI metrics were highly susceptible to noise and experimental design. The influence of fixed parameter selection for the NODDI model was found to be considerable, as was the impact of initial tensor fitting in the MAP-MRI model.
  
  
  
  Across DTI, DKI, MAP-MRI, and NODDI, a wide range of dependence on experimental factors was observed that elucidate principles and practical implications for advanced diffusion MRI. Magn Reson Med 78:1767-1780, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA.|The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, USA.
authors.forename: Elizabeth B
authors.initials: EB
authors.lastname: Hutchinson
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Alexandru V
authors.initials: AV
authors.lastname: Avram
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA.|The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, USA.
authors.forename: M Okan
authors.initials: MO
authors.lastname: Irfanoglu
authors.affiliation: National Intrepid Center of Excellence, Bethesda, Maryland, USA.
authors.forename: C Guan
authors.initials: CG
authors.lastname: Koay
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA.|The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, USA.
authors.forename: Alan S
authors.initials: AS
authors.lastname: Barnett
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA.|The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, USA.
authors.forename: Michal E
authors.initials: ME
authors.lastname: Komlosh
authors.affiliation: Department of Biomedical Engineering, Linköping University, Linköping, Sweden.
authors.forename: Evren
authors.initials: E
authors.lastname: Özarslan
authors.affiliation: The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, Maryland, USA.|Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.
authors.forename: Susan C
authors.initials: SC
authors.lastname: Schwerin
authors.affiliation: Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Juliano
authors.affiliation: Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Carlo
authors.initials: C
authors.lastname: Pierpaoli
mesh_terms: D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D051379:Mice; D008962:Models, Theoretical; D059906:Neuroimaging / Q000379:methods*; D014867:Water
chemical_list: D014867:Water
keywords: DWI sampling; diffusion kurtosis imaging; diffusion tensor imaging; mean apparent propagator MRI; neurite orientation dispersion and density imaging; noise floor bias