title: A Nondestructive Method to Distinguish the Internal Constituent Architecture of the Intervertebral Discs Using 9.4 Tesla Magnetic Resonance Imaging.
abstract: METHODS
  An in vitro study of the intervertebral disc (IVD) structure using 9.4T magnetic resonance imaging (MRI).
  
  
  OBJECTIVE
  Investigate the potential of ultrahigh-field strength MRI for higher quality 3-dimensional (3D) volumetric MRI datasets of the IVD to better distinguish structural details.
  
  
  BACKGROUND
  MRI has the advantages of being nondestructive and 3D in comparison to most techniques used to obtain the structural details of biological tissues, however, its poor image quality at higher resolution is a limiting factor. Ultrahigh-field MRI could improve the imaging of biological tissues but the current understanding of its application for spinal tissue is limited.
  
  
  METHODS
  2 ovine spinal segments (C7-T1, T2-T3) containing the IVD were separately imaged using 2 sequences; 3D spin echo (multislice-multiecho) pulse sequence for the C7-T1 sample and 3D gradient echo (fast-low-angle-shot) pulse sequence for the T2-T3 sample. The C7-T1 sample was subsequently decalcified and imaged again using the same scanning parameters. Histological sections obtained from the decalcified sample were stained followed by digital scanning. Observations from corresponding MRI slices and histological sections were compared as a method of confirmation of morphology captured under MRI. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and relative-contrast values were calculated for quantitative evaluation of image quality.
  
  
  RESULTS
  Measurements from histology sections and corresponding MRI slices matched well. Both sequences revealed finer details of the IVD structure. Under the spin echo sequence, the annulus lamellae architecture was distinguishable and the SNR and CNR values were higher. The relative contrast was considerably higher between high (nucleus) and low (bone) signal constituents, but between the nucleus and the annulus the relative contrast was low. Under the gradient echo sequence, although the relative contrasts between constituents were poor, the fiber orientation was clearly manifested.
  
  
  CONCLUSIONS
  The obtained positive results demonstrate the potential of ultrahigh-field strength MRI to nondestructively capture the IVD structure.
  
  
  METHODS
  N/A.
authors.affiliation: *Institute of Medical and Biological Engineering, University of Leeds, Leeds, United Kingdom†Division of Medical Physics, University of Leeds, Leeds, United Kingdom‡The Leeds Institute of Cancer and Pathology, Leeds Teaching Hospitals NHS Trust, St James's University Hospital, Beckett Street, Leeds, United Kingdom§School of Computing, University of Leeds, Leeds, United Kingdom¶School of Physics and Astronomy, University of Leeds, Leeds, United Kingdom.
authors.forename: Vithanage N
authors.initials: VN
authors.lastname: Wijayathunga
authors.forename: John P
authors.initials: JP
authors.lastname: Ridgway
authors.forename: Eileen
authors.initials: E
authors.lastname: Ingham
authors.forename: Darren
authors.initials: D
authors.lastname: Treanor
authors.forename: Duane
authors.initials: D
authors.lastname: Carey
authors.forename: Andy
authors.initials: A
authors.lastname: Bulpitt
authors.forename: Derek
authors.initials: D
authors.lastname: Magee
authors.forename: Robin
authors.initials: R
authors.lastname: Damion
authors.forename: Ruth K
authors.initials: RK
authors.lastname: Wilcox
mesh_terms: D000818:Animals; D007091:Image Processing, Computer-Assisted; D007403:Intervertebral Disc / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D012756:Sheep; D059629:Signal-To-Noise Ratio