title: Correlative BOLD MR imaging of stages of synovitis in a rabbit model of antigen-induced arthritis.
abstract: BACKGROUND
  Because of the ability of blood-oxygen-level-dependent (BOLD) MRI to assess blood oxygenation changes within the microvasculature, this technique holds potential for evaluating early perisynovial changes in inflammatory arthritis.
  
  
  OBJECTIVE
  To evaluate the feasibility of BOLD MRI to detect interval perisynovial changes in knees of rabbits with inflammatory arthritis.
  
  
  METHODS
  Rabbit knees were injected with albumin (n=9) or saline (n=6) intra-articularly, or were not injected (control knees, n=9). Except for two rabbits (albumin-injected, n=2 knees; saline-injected, n=2 knees) that unexpectedly died on days 7 and 21 of the experiment, respectively, all other animals were scanned with BOLD MRI on days 0, 1, 7, 14, 21 and 28 after induction of arthritis. T2*-weighted gradient-echo MRI was performed during alternate 30 s of normoxia/hyperoxia. BOLD MRI measurements were compared with clinical, laboratory and histological markers.
  
  
  RESULTS
  Percentage of activated voxels was significantly greater in albumin-injected knees than in contralateral saline-injected knees (P=0.04). For albumin-injected knees (P<0.05) and among different categories of knees (P=0.009), the percentage of activated BOLD voxels varied over time. A quadratic curve for on-and-off BOLD difference was delineated for albumin- and saline-injected knees over time (albumin-injected, P=0.047; saline-injected, P=0.009). A trend toward a significant difference in synovial histological scores between albumin-injected and saline-injected knees was noted only for acute scores (P=0.07).
  
  
  CONCLUSIONS
  As a proof of concept, BOLD MRI can depict perisynovial changes during progression of experimental arthritis.
authors.affiliation: Department of Diagnostic Imaging, The Hospital for Sick Children, 555 University Ave., Toronto, Canada. andrea.doria@sickkids.ca
authors.forename: Andrea S
authors.initials: AS
authors.lastname: Doria
authors.forename: Adrian
authors.initials: A
authors.lastname: Crawley
authors.forename: Harpal
authors.initials: H
authors.lastname: Gahunia
authors.forename: Rahim
authors.initials: R
authors.lastname: Moineddin
authors.forename: Tammy
authors.initials: T
authors.lastname: Rayner
authors.forename: Vivian
authors.initials: V
authors.lastname: Tassos
authors.forename: Anguo
authors.initials: A
authors.lastname: Zhong
authors.forename: Kenneth
authors.initials: K
authors.lastname: Pritzker
authors.forename: Maria
authors.initials: M
authors.lastname: Mendes
authors.forename: Roland
authors.initials: R
authors.lastname: Jong
authors.forename: Robert B
authors.initials: RB
authors.lastname: Salter
mesh_terms: D000818:Animals; D000941:Antigens; D001168:Arthritis / Q000139:chemically induced* / Q000473:pathology*; D004195:Disease Models, Animal; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011817:Rabbits; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012709:Serum Albumin; D013223:Statistics as Topic
chemical_list: D000941:Antigens; D012709:Serum Albumin