Contrast-enhanced MRI compared to histological findings in the temporomandibular joint of antigen-induced arthritis in young rabbits

OBJECTIVE

To study the correlation between histological findings and Magnetic Resonance Imaging (MRI) findings in experimentally induced arthritis in the temporomandibular joint (TMJ) of growing rabbits and to study the effect of intraarticular corticosteroid injections.

METHODS

Arthritis was induced by ovalbumin in the left TMJ of 44 pre-sensibilized rabbits. Nine animals died during this procedure. Eight of the remaining animals with induced arthritis were treated with intraarticular corticosteroid injections one week after induction of arthritis. Twelve rabbits served as controls. MRI enhanced with Gadolinium-DTPA was performed on all animals 1 to 2 weeks after induction of arthritis and again before sacrifice and the degree of enhancement was calculated. Histology of the condyle was performed and degree of villous hyperplasia, synovial thickness, infiltration of inflammatory cells and pannus was graded.

RESULTS

TMJ arthritis was successfully induced in the rabbits and was verified by enhancement of the MRI and by histological changes one week after the induction. Joints treated with intraarticular corticosteroid injections revealed complete inhibition of the inflammation.

CONCLUSION

Enhancement of MRI in antigen-induced arthritis in the TMJ associated well with inflammatory changes shown histologically. An intraarticular corticosteroid injection prevents the initial inflammatory response in experimentally induced TMJ arthritis.

Determination of connectivity density in human iliac crest bone biopsies assessed by a computerized method

The aim of the present study was to design a computer program (based on the ConnEulor principle) for direct measurement of 3-D connectivity density in iliac crest bone sections, as used for conventional histomorphometry. We used the physical disector principle and developed an algorithm for nonlinear alignment of the disector pairs. 3-D connectivity was evaluated in transiliac specimens from 30 nonselected autopsy cases of 14 men (age range 20-84 years) and 16 women (age range 20-96 years). In order to visualize the findings from the disector pairs, 3-D reconstruction was performed for two of the iliac crest biopsies. The designed computer program aligns the two sections forming a disector pair and automatically depicts the differences between the images, thereby making correct, direct connectivity density measurements available for conventional bone research.