title: Quantification of articular cartilage in the knee with three-dimensional MR imaging.
abstract: OBJECTIVE
  To determine the volume of articular cartilage in cadavers, patients, and healthy volunteers by using a volumetric, fat-suppressed spoiled gradient-recalled signal acquisition in the steady state (SPGR) magnetic resonance (MR) sequence.
  
  
  METHODS
  Sagittal MR images were obtained with a fat-suppressed SPGR sequence (repetition time, 52 msec; echo time, 10 msec; 60 degrees flip angle; 3.0-3.5-mm partitions, 256 x 192 matrix, two signals acquired). The cartilaginous surfaces of the tibia, femur, and patella were planimetrically defined with a three-dimensional workstation. A three-dimensional model volume was created by threshold segmenting the cartilage from the adjacent tissues. The volume as calculated by using MR imaging was compared with the actual volume of the cartilage specimens.
  
  
  RESULTS
  Observed measurements correlated with actual weight and volume displacement measurements with an accuracy of 82%-99% and linear correlation coefficients of 0.99 (P = 2.5e-15) and 0.99 (P = 4.4e-15). Precision of segmentation in healthy volunteers yielded a coefficient of variation of 0.4% for interobserver variability and 0.3% for intraobserver variability.
  
  
  CONCLUSIONS
  This pilot study suggests that accurate volumetric calculations of knee articular cartilage are possible with currently available MR imaging pulse sequences and a commercially available work station.
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Boston 02114, USA.
authors.forename: D E
authors.initials: DE
authors.lastname: Dupuy
authors.forename: R M
authors.initials: RM
authors.lastname: Spillane
authors.forename: M S
authors.initials: MS
authors.lastname: Rosol
authors.forename: D I
authors.initials: DI
authors.lastname: Rosenthal
authors.forename: W E
authors.initials: WE
authors.lastname: Palmer
authors.forename: D W
authors.initials: DW
authors.lastname: Burke
authors.forename: A E
authors.initials: AE
authors.lastname: Rosenberg
mesh_terms: D000328:Adult; D000368:Aged; D002102:Cadaver; D002358:Cartilage, Articular / Q000033:anatomy & histology / Q000473:pathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007719:Knee Joint / Q000033:anatomy & histology / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010003:Osteoarthritis / Q000473:pathology*; D010865:Pilot Projects