Dynamic contrast-enhanced MRI quantification of synovium microcirculation in experimental arthritis.
OBJECTIVE
Our objective was to analyze MRI contrast-enhancement patterns in arthritic and nonarthritic knees and the relationship of those patterns with clinical, laboratory, and histologic synovium markers.


METHODS
Dynamic contrast-enhanced MRI was performed in nine arthritic and three nonarthritic knees of juvenile rabbits. A two-compartment pharmacokinetic model of signal intensity-time data was implemented to generate parametric maps of signal slope, maximal percentage of signal change, capillary permeability, leakage space volume, and time-to-peak. MRI values were compared with clinical, laboratory, and histologic markers for evaluation of synovial changes during the progression of arthritis.


RESULTS
Parametric maps of capillary permeability and signal slope depicted significant differences between arthritic and nonarthritic knees. Arthritic knees showed increased capillary permeability (p = 0.006) and signal slope (p = 0.01) with time after onset of disease as opposed to nonarthritic knees (permeability, p = 0.65; slope, p = 0.56). Significant correlations were found between temporal changes in capillary permeability (p = 0.002), signal slope (p = 0.003), and serum concentrations of amyloid A. No relationship was noted between any MRI parameters and histologic scores. The discriminative power of MRI indexes varied according to the stage of arthritis: time-to-peak was most accurate for differentiation of presence versus absence of arthritis in early arthritis (day 1, p = 0.0002), and signal slope was most accurate in midterm arthritis (day 14, p = 0.001).


CONCLUSIONS
In vivo capillary permeability and signal slope have distinctive dynamic MRI properties. The accuracy of MRI parameters for diagnostic evaluation of experimental arthritis differs according to the stage of disease.
Department of Diagnostic Imaging, Research Institute, The Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada.
Andrea S
AS
Doria
Michael
M
Noseworthy
Wendy
W
Oakden
Rahim
R
Moineddin
Tammy
T
Rayner
Vivian
V
Tassos
Doreen
D
Engelberts
Kenneth
K
Pritzker
Marianne
M
Rogers
Roland
R
Jong
Paul
P
Babyn
D000818:Animals; D001168:Arthritis / Q000473:pathology*; D003287:Contrast Media; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008833:Microcirculation; D011817:Rabbits; D013583:Synovial Membrane / Q000098:blood supply* / Q000473:pathology*
D003287:Contrast Media