title: A rapid, novel method of volumetric assessment of MRI-detected subchondral bone marrow lesions in knee osteoarthritis.
abstract: OBJECTIVE
  To assess reliability and validity of a semi-automated quantitative method for osteoarthritis (OA)-related bone marrow lesion (BML) assessment in the femur and tibia.
  
  
  METHODS
  In a cross-sectional study of subjects with knee OA, we examined concurrent criterion and clinical validation of a novel method of semi-automated quantitative BML measurement. The primary outcome was total segmented BML volume in femoral and tibial medial and lateral knee compartments. Criterion validation was examined through comparison of BML volumes with Whole-Organ Magnetic Resonance Imaging Score (WORMS) scoring. Clinical validation was examined via associations of tibial and femoral BML volume with the Western Ontario and McMaster University OA Index weight-bearing pain questions.
  
  
  RESULTS
  Among the 115 subjects, mean age was 62 years, mean BMI 30.4 (kg/m(2)), 84% were white and 52% male. The intra-class correlation coefficients (ICC) for intra-reader reliability was 0.96 and 0.97 for inter-reader reliability. Significant Spearman's correlations were found between segmented BML volume and WORMS BML scoring for tibial medial (0.75) and lateral (0.73) compartments, and for femoral medial (0.72) and lateral (0.88) compartments. Significant positive associations were found between weight-bearing pain and total femoral BML volume (P < 0.003), but not total tibial BML (P < 0.101).
  
  
  CONCLUSIONS
  We have documented a moderately strong correlation between a novel measurement method of femoral and tibial BML volume and semi-quantitative WORMS scores, providing evidence of criterion validity. The hypothesis that weight-bearing pain was associated with BML volume was confirmed for total femoral BML volume but not total tibial BML volume. The lack of association between tibial BML volume and pain requires further investigation.
authors.affiliation: Brigham and Women's Hospital, Harvard Medical School, Boston, MA 2115, USA. cratzlaff@bwh.harvard.edu
authors.forename: C
authors.initials: C
authors.lastname: Ratzlaff
authors.forename: A
authors.initials: A
authors.lastname: Guermazi
authors.forename: J
authors.initials: J
authors.lastname: Collins
authors.forename: J N
authors.initials: JN
authors.lastname: Katz
authors.forename: E
authors.initials: E
authors.lastname: Losina
authors.forename: C
authors.initials: C
authors.lastname: Vanwyngaarden
authors.forename: R
authors.initials: R
authors.lastname: Russell
authors.forename: T
authors.initials: T
authors.lastname: Iranpour
authors.forename: J
authors.initials: J
authors.lastname: Duryea
mesh_terms: D000368:Aged; D001855:Bone Marrow Diseases / Q000473:pathology*; D003430:Cross-Sectional Studies; D005260:Female; D005269:Femur / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000473:pathology*; D015203:Reproducibility of Results; D013977:Tibia / Q000473:pathology*; D016474:Weight-Bearing / Q000502:physiology