title: Macroscopic structure of articular cartilage of the tibial plateau: influence of a characteristic matrix architecture on MRI appearance.
abstract: OBJECTIVE
  The purpose of our study was to describe the structural organization of the extracellular matrix of articular cartilage of the tibial plateau and its influence on MRI appearance.
  
  
  METHODS
  Spin-echo images of 11 resected tibial plateaus acquired at 7 T were compared with the structure of the extracellular matrix as shown by fracture sectioning the samples in the plane of imaging. Four samples were scanned at two different orientations relative to the main magnetic field (B(0)). T2 maps were acquired in two orientations on three of these four samples.
  
  
  RESULTS
  On the basis of the presence of reproducible regional variations in the shape of the matrix, a characteristic matrix architecture was described. The location of peak signal intensity and T2 on MRI correlated with the level at which the matrix was estimated to be aligned at approximately 55 degrees to B(0) (r = 0.91). This correlation of matrix orientation relative to B(0) with T2 and signal intensity on MRI was not altered by regional variations in the shape of the matrix or by imaging samples at two different orientations.
  
  
  CONCLUSIONS
  The structure of the extracellular matrix, through its orientation-dependent influence on T2 decay, exerts a strong influence on the MRI appearance of cartilage. At the tibial plateau, a characteristic matrix architecture is associated with an equally characteristic MRI appearance.
authors.affiliation: Department of Radiology, Dartmouth Medical School, Dartmouth-Hitchcock Medical Center, One Medical Center Dr, Lebanon, NH 03756, USA.
authors.forename: Douglas W
authors.initials: DW
authors.lastname: Goodwin
authors.forename: Youssef Zaim
authors.initials: YZ
authors.lastname: Wadghiri
authors.forename: Haoqin
authors.initials: H
authors.lastname: Zhu
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Vinton
authors.forename: Eric D
authors.initials: ED
authors.lastname: Smith
authors.forename: Jeff F
authors.initials: JF
authors.lastname: Dunn
mesh_terms: D000328:Adult; D000368:Aged; D002358:Cartilage, Articular / Q000473:pathology*; D005109:Extracellular Matrix / Q000473:pathology* / Q000648:ultrastructure; D005260:Female; D024022:Fibrillar Collagens / Q000648:ultrastructure; D006801:Humans; D021621:Imaging, Three-Dimensional; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D013977:Tibia / Q000473:pathology*
chemical_list: D024022:Fibrillar Collagens