title: Quantification of bone marrow lesion volume and volume change using semi-automated segmentation: data from the osteoarthritis initiative.
abstract: BACKGROUND
  To determine the validity of a semi-automated segmentation of bone marrow lesions (BMLs) in the knee.
  
  
  METHODS
  Construct validity of the semi-automated BML segmentation method was explored in two studies performed using sagittal intermediate weighted, turbo spine echo, fat-suppressed magnetic resonance imaging sequences obtained from the Osteoarthritis Initiative. The first study (n = 48) evaluated whether tibia BML volume was different across Boston Leeds Osteoarthritis Knee Scores (BLOKS) for tibia BMLs (semiquantitative grades 0 to 3). In the second study (n = 40), we evaluated whether BML volume change was associated with changes in cartilage parameters. The knees in both studies were segmented by one investigator. We performed Wilcoxon signed-rank tests to determine if tibia BML volume was different between adjacent BLOKS BML scores and calculated Spearman correlation coefficients to assess the relationship between 2-year BML volume change and 2-year cartilage morphometry change (significance was p ≤ 0.05).
  
  
  RESULTS
  BML volume was significantly greater between BLOKS BML score 0 and 1 (z = 2.85, p = 0.004) and BLOKS BML scores 1 and 2 (z = 3.09, p = 0.002). There was no significant difference between BLOKS BML scores 2 and 3 (z = -0.30, p = 0.77). Increased tibia BML volume was significantly related to increased tibia denuded area (Spearman r = 0.42, p = 0.008), decreased tibia cartilage thickness (Spearman r = -0.46, p = 0.004), increased femur denuded area (Spearman r = 0.35, p = 0.03), and possibly decreased femur cartilage thickness (Spearman r = -0.30, p = 0.07) but this last finding was not statistically significant.
  
  
  CONCLUSIONS
  The new, efficient, and reliable semi-automated BML segmentation method provides valid BML volume measurements that increase with greater BLOKS BML scores and confirms previous reports that BML size is associated with longitudinal cartilage loss.
authors.affiliation: Department of Electrical and Computer Engineering, Tufts University, 216 Halligan Hall, Medford, MA 02155, USA.
authors.forename: Jincheng
authors.initials: J
authors.lastname: Pang
authors.forename: Jeffrey B
authors.initials: JB
authors.lastname: Driban
authors.forename: Geoffroy
authors.initials: G
authors.lastname: Destenaves
authors.forename: Eric
authors.initials: E
authors.lastname: Miller
authors.forename: Grace H
authors.initials: GH
authors.lastname: Lo
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Ward
authors.forename: Lori Lyn
authors.initials: LL
authors.lastname: Price
authors.forename: John A
authors.initials: JA
authors.lastname: Lynch
authors.forename: Charles B
authors.initials: CB
authors.lastname: Eaton
authors.forename: Felix
authors.initials: F
authors.lastname: Eckstein
authors.forename: Timothy E
authors.initials: TE
authors.lastname: McAlindon
mesh_terms: D000368:Aged; D001853:Bone Marrow / Q000473:pathology*; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000473:pathology* / Q000601:surgery*; D012720:Severity of Illness Index