title: The shear modulus of the nucleus pulposus measured using magnetic resonance elastography: a potential biomarker for intervertebral disc degeneration.
abstract: OBJECTIVE
  This study aims to: (1) measure the shear modulus of nucleus pulposus (NP) in intact human vertebra-disc-vertebra segments using a magnetic resonance elastography setup for a 7T whole-body scanner, (2) quantify the effect of disc degeneration on the NP shear modulus measured using magnetic resonance elastography, and (3) compare the NP shear modulus to other magnetic resonance-based biomarkers of dis degeneration.
  
  
  METHODS
  Thirty intact human disc segments were classified as normal, mild, or severely degenerated. The NP shear modulus was measured using a custom-made setup that included a novel inverse method less sensitive to noisy displacements. T2 relaxation time was measured at 7T. The accuracy of these parameters to classify different degrees of degeneration was evaluated using receiver operating characteristic curves.
  
  
  RESULTS
  The magnetic resonance elastography measure of shear modulus in the NP was able to differentiate between normal, mild degeneration, and severe degeneration. The T2 relaxation time was able to differentiate between normal and mild degeneration, but it could not distinguish between mild and severe degeneration.
  
  
  CONCLUSIONS
  This study shows that the NP shear modulus measured using magnetic resonance elastography is sensitive to disc degeneration and has the potential of being used as a clinical tool to quantify the mechanical integrity of the intervertebral disc.
authors.affiliation: Department of Biomedical Engineering, University of Delaware, Newark, Delaware, USA.
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Cortes
authors.forename: Jeremy F
authors.initials: JF
authors.lastname: Magland
authors.forename: Alexander C
authors.initials: AC
authors.lastname: Wright
authors.forename: Dawn M
authors.initials: DM
authors.lastname: Elliott
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000032:analysis; D002102:Cadaver; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional; D066298:In Vitro Techniques; D055959:Intervertebral Disc Degeneration / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged
chemical_list: D015415:Biomarkers
keywords: degeneration biomarkers; intervertebral disc; magnetic resonance elastography
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