title: Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC): intra- and interobserver variability in standardized drawing of regions of interest.
abstract: OBJECTIVE
  To establish the reproducibility of a standardized region of interest (ROI) drawing procedure in delayed gadolinium-enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC).
  
  
  METHODS
  A large ROI in lateral and medial femoral weight-bearing cartilage was drawn in images of 12 healthy male volunteers by 6 investigators with different skills in MRI. The procedure was done twice, with a 1-week interval. Calculated T1-values were evaluated for intra- and interobserver variability.
  
  
  RESULTS
  The mean interobserver variability for both compartments ranged between 1.3% and 2.3% for the 6 different investigators without correlation to their experience in MRI. Post-contrast intra-observer variability was low in both the lateral and the medial femoral cartilage, 2.6% and 1.5%, respectively. The larger variability in lateral than in medial cartilage was related to slightly longer and thinner ROIs.
  
  
  CONCLUSIONS
  Intra-observer variability and interobserver variability are both low when a large standardized ROI is used in dGEMRIC. The experience of the investigator does not affect the variability, which further supports a clinical applicability of the method.
authors.affiliation: Department of Orthopedics, Malmö University Hospital, Lund University, Malmö, Sweden.
authors.forename: C J
authors.initials: CJ
authors.lastname: Tiderius
authors.forename: J
authors.initials: J
authors.lastname: Tjörnstrand
authors.forename: P
authors.initials: P
authors.lastname: Akeson
authors.forename: K
authors.initials: K
authors.lastname: Södersten
authors.forename: L
authors.initials: L
authors.lastname: Dahlberg
authors.forename: P
authors.initials: P
authors.lastname: Leander
mesh_terms: D000328:Adult; D002356:Cartilage / Q000033:anatomy & histology*; D002358:Cartilage, Articular / Q000033:anatomy & histology*; D003287:Contrast Media; D019786:Gadolinium DTPA; D006801:Humans; D007717:Knee / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging; D008297:Male; D015588:Observer Variation; D015203:Reproducibility of Results
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA