title: High-resolution mechanical imaging of glioblastoma by multifrequency magnetic resonance elastography.
abstract: OBJECTIVE
  To generate high-resolution maps of the viscoelastic properties of human brain parenchyma for presurgical quantitative assessment in glioblastoma (GB).
  
  
  METHODS
  Twenty-two GB patients underwent routine presurgical work-up supplemented by additional multifrequency magnetic resonance elastography. Two three-dimensional viscoelastic parameter maps, magnitude |G*|, and phase angle φ of the complex shear modulus were reconstructed by inversion of full wave field data in 2-mm isotropic resolution at seven harmonic drive frequencies ranging from 30 to 60 Hz.
  
  
  RESULTS
  Mechanical brain maps confirmed that GB are composed of stiff and soft compartments, resulting in high intratumor heterogeneity. GB could be easily differentiated from healthy reference tissue by their reduced viscous behavior quantified by φ (0.37±0.08 vs. 0.58±0.07). |G*|, which in solids more relates to the material's stiffness, was significantly reduced in GB with a mean value of 1.32±0.26 kPa compared to 1.54±0.27 kPa in healthy tissue (P = 0.001). However, some GB (5 of 22) showed increased stiffness.
  
  
  CONCLUSIONS
  GB are generally less viscous and softer than healthy brain parenchyma. Unrelated to the morphology-based contrast of standard magnetic resonance imaging, elastography provides an entirely new neuroradiological marker and contrast related to the biomechanical properties of tumors.
authors.affiliation: Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Kaspar-Josche
authors.initials: KJ
authors.lastname: Streitberger
authors.affiliation: Department of Neuroradiology, Universitätsmedizin Leipzig, Leipzig, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Reiss-Zimmermann
authors.affiliation: Department of Neurosurgery, Universitätsmedizin Göttingen, Göttingen, Germany.
authors.forename: Florian Baptist
authors.initials: FB
authors.lastname: Freimann
authors.affiliation: Department of Neurosurgery, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Simon
authors.initials: S
authors.lastname: Bayerl
authors.affiliation: Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Jing
authors.initials: J
authors.lastname: Guo
authors.affiliation: Department of Neurosurgery, Universitätsmedizin Leipzig, Leipzig, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Arlt
authors.affiliation: Institute of Neuroradiology, Universitätsmedizin Göttingen, Göttingen, Germany; NeuroCure, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Wuerfel
authors.affiliation: Institute of Medical Informatics, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Braun
authors.affiliation: Department of Neuroradiology, Universitätsmedizin Leipzig, Leipzig, Germany.
authors.forename: Karl-Titus
authors.initials: KT
authors.lastname: Hoffmann
authors.affiliation: Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Ingolf
authors.initials: I
authors.lastname: Sack
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001921:Brain / Q000473:pathology; D001931:Brain Mapping / Q000295:instrumentation / Q000379:methods*; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000473:pathology; D004548:Elasticity; D054459:Elasticity Imaging Techniques; D005260:Female; D005909:Glioblastoma / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D057234:Preoperative Period