title: Validation of cartilage volume and thickness measurements in the human shoulder with quantitative magnetic resonance imaging.
abstract: OBJECTIVE
  To validate quantitative magnetic resonance imaging (qMRI) for the assessment of cartilage volume and thickness in thin and curved cartilage layers, such as the shoulder.
  
  
  METHODS
  Eight shoulder specimens from healthy individuals (aged 31-69 years) were investigated using a 3D gradient echo sequence with selective water excitation. After segmentation with a B-spline Snake algorithm, the cartilage volume and thickness were determined three dimensionally. The cartilage volume data were compared with water displacement of surgically removed tissue, and the thickness with A-mode ultrasound.
  
  
  RESULTS
  The glenoid and humeral head cartilage volume from qMRI agreed highly with that from water displacement (systematic difference, +/-1 to +/-3%; absolute difference, 4 to 7%). For the cartilage thickness, the mean systematic difference ranged from -17% (mean cartilage thickness of the glenoid) to +7% (maximal cartilage thickness of the glenoid); the standard error of the estimate was 3.7% for the humeral head, and 6.4% for the glenoid.
  
  
  CONCLUSIONS
  The applied technique can be used for accurate determination of cartilage volume and thickness in human joints with highly curved and thin cartilage layers, such as the shoulder. In vivo application of this method will depend on the development of efficient surface coils that allow high resolution imaging under in situ conditions.
authors.affiliation: Research Group for Kinematics and Biomechanics, Department of Orthopedic Surgery, University of Frankfurt, Marienburgstrasse 2, 60528, Frankfurt, Germany. h.graichen@em.uni-frankfurt.de
authors.forename: H
authors.initials: H
authors.lastname: Graichen
authors.forename: J
authors.initials: J
authors.lastname: Jakob
authors.forename: R
authors.initials: R
authors.lastname: von Eisenhart-Rothe
authors.forename: K-H
authors.initials: KH
authors.lastname: Englmeier
authors.forename: M
authors.initials: M
authors.lastname: Reiser
authors.forename: F
authors.initials: F
authors.lastname: Eckstein
mesh_terms: D000328:Adult; D000368:Aged; D002358:Cartilage, Articular / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000592:standards*; D008297:Male; D008875:Middle Aged; D012785:Shoulder Joint / Q000033:anatomy & histology*