Measurement of radiographic changes in adjuvant-induced arthritis in rats by quantitative image analysis.
OBJECTIVE
To apply quantitative analytical methods to the evaluation of radiographic images in experimental arthritis.


METHODS
Adjuvant was used to induce arthritis in rats. Arthritis progression was followed by conventional methods. In addition, digitized images of radiographs of the calcaneus were examined for changes in the mean and in the distribution pattern of gray values. Periosteal new bone formation was measured as an increase in image area of the calcaneus.


RESULTS
Significant changes in the gray value profile and increases in periosteal bone formation occurred in arthritic rats. More extensive changes occurred in Lewis rats than in Sprague-Dawley rats. Analysis of serial radiographs revealed an initial decrease in the density of juxtaarticular bone, followed by progressive increases in gray value variation due to concurrent bone loss and bone formation. Eventually, bone formation in arthritic rats resulted in increased gray values above those in nonarthritic rats.


CONCLUSIONS
Image analysis represents a sensitive, quantitative method for detecting radiographic changes in experimental arthritis.
Esser
R E
RE
Marion Merrell Dow Research Institute, Cincinnati, Ohio.
Hildebrand
A R
AR
Angelo
R A
RA
Watts
L M
LM
Murphey
M D
MD
Baugh
L E
LE
D000818:Animals; D001169:Arthritis, Experimental / Q000000981:diagnostic imaging* / Q000473:pathology; D002111:Calcaneus / Q000000981:diagnostic imaging; D002908:Chronic Disease; D018450:Disease Progression; D005260:Female; D007091:Image Processing, Computer-Assisted; D011856:Radiographic Image Enhancement; D051381:Rats; D011917:Rats, Inbred Lew; D017207:Rats, Sprague-Dawley