title: Simultaneous, multidirectional acquisition of displacement fields in magnetic resonance elastography of the in vivo human brain.
abstract: BACKGROUND
  To implement a multidirectional motion encoding scheme for magnetic resonance elastography (MRE) of the human brain with reduced acquisition time, and investigate its performance relative to a conventional MRE scheme.
  
  
  METHODS
  The sample interval modulation (SLIM) scheme was implemented in a multishot, variable density spiral MRE sequence. The brains of seven healthy volunteers were investigated with both SLIM-MRE and conventional MRE acquisitions in a single imaging session on a clinical 3 Tesla MRI scanner with 50 Hz vibration. Following extraction of displacement fields, complex shear modulus property maps were estimated for each encoding concept.
  
  
  RESULTS
  The SLIM-MRE and conventional MRE acquisitions produced deformation fields that were nearly identical and exhibited an average correlation coefficient of 0.95 (all p < 0.05). Average properties of white matter differed between the two acquisitions by less than 5% for all volunteers, which is better than reproducibility estimates for conventional MRE alone.
  
  
  CONCLUSIONS
  The use of SLIM provides very similar quantitative property estimates compared with the conventional MRE encoding scheme. The SLIM acquisition is 2.5 times faster than the conventional acquisition, and may speed the adoption of MRE in clinical settings.
authors.affiliation: The Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, USA.
authors.forename: Dieter
authors.initials: D
authors.lastname: Klatt
authors.affiliation: Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
authors.forename: Curtis L
authors.initials: CL
authors.lastname: Johnson
authors.affiliation: The Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, USA.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Magin
mesh_terms: D000328:Adult; D000465:Algorithms; D016880:Anisotropy; D001921:Brain / Q000033:anatomy & histology* / Q000502:physiology*; D055119:Elastic Modulus / Q000502:physiology; D054459:Elasticity Imaging Techniques / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D060526:Magnetic Fields; D008297:Male; D009038:Motion; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D033081:Shear Strength / Q000502:physiology
keywords: brain mechanical properties; displacement field; magnetic resonance elastography; multidirectional motion encoding; multishot spiral