title: Morphology of the cartilaginous endplates in human intervertebral disks with ultrashort echo time MR imaging.
abstract: OBJECTIVE
  To image human disk-bone specimens by using conventional spin-echo (SE) and ultrashort echo time (TE) techniques, to describe the morphology at magnetic resonance (MR) imaging, and to identify tissue components contributing to high signal intensity near the cartilaginous endplates (CEPs).
  
  
  METHODS
  This study was exempt from institutional review board approval, and informed consent was not required. Five cadaveric lumbar spines (mean age, 61 years ± 11) were prepared into six sample types containing different combinations of disk, uncalcified CEP, calcified CEP, and subchondral bone components and were imaged with proton density-weighted SE (repetition time msec/TE msec, 2000/15) and ultrashort TE (300/0.008, 6.6, echo-subtraction) sequences. Images were evaluated to determine the presence of intermediate-to-high signal intensity in regions excluding the bone marrow. Logistic regression was used to determine which tissue components were significant predictors of the presence of signal intensity for each MR technique.
  
  
  RESULTS
  On ultrashort TE MR images, intact disk/uncalcified CEP/calcified CEP/bone samples exhibited bilaminar intermediate-to-high signal intensity in the region near the CEP, consistent with the histologic appearance of uncalcified and calcified CEPs. Conversely, proton density-weighted SE images exhibited low signal intensity in this region. Results of logistic regression suggested that the presence of uncalcified CEP (P = .023) and calcified CEP (P = .007) in the sample were strong predictors of the presence of signal intensity on ultrashort TE images, whereas the disk was the only predictor (P < .001) of signal intensity on proton density-weighted SE images.
  
  
  CONCLUSIONS
  Ultrashort TE imaging, unlike proton density-weighted SE imaging, enabled direct visualization of the uncalcified and calcified CEP. Evaluation of the morphology and identification of sources of signal intensity at ultrashort TE MR imaging provides opportunities to potentially aid in the understanding of degenerative disk disease.
authors.affiliation: Department of Radiology, University of California-San Diego, 408 Dickinson St, San Diego, CA 92103-8226, USA. wbae@ucsd.edu
authors.forename: Won C
authors.initials: WC
authors.lastname: Bae
authors.forename: Sheronda
authors.initials: S
authors.lastname: Statum
authors.forename: Zhao
authors.initials: Z
authors.lastname: Zhang
authors.forename: Tomonori
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Tanya
authors.initials: T
authors.lastname: Wolfson
authors.forename: Anthony C
authors.initials: AC
authors.lastname: Gamst
authors.forename: Jiang
authors.initials: J
authors.lastname: Du
authors.forename: Graeme M
authors.initials: GM
authors.lastname: Bydder
authors.forename: Koichi
authors.initials: K
authors.lastname: Masuda
authors.forename: Christine B
authors.initials: CB
authors.lastname: Chung
mesh_terms: D002102:Cadaver; D005260:Female; D006801:Humans; D007403:Intervertebral Disc / Q000473:pathology*; D016015:Logistic Models; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged