2007 Volume 32 Issue 1 Pages 11-24
The objective of this study was to establish an X-ray radiographic evaluation method of regenerated bone by comparison of X-ray photograph, bone mineral content, and bone morphometry by microfocus X-ray CT in a bone regeneration model using an acidic gelatin disc (AGD) containing a sustained release basic fibroblast growth factor (bFGF) system. A defect 6 mm in diameter was made in the cranium of 36 Wistar rats aged 16 weeks (6 animals per group). bFGF (1.0 and 10.0 μg) and physiological saline (control) were added to AGD with a water content of 81.8 ± 0.2%, and the discs were implanted in the bone defects. The animals were sacrificed after 4 and 8 weeks, and evaluated. Regenerated bone was evaluated by X-ray photodensitometry using an aluminum step wedge and imaging plate JP) and based on the CT concentration (pixel concentration) and volume on microfocus X-ray CT. Photodensitometry showed that bFGF promoted bone regeneration with time in a concentration-dependent manner. Microfocus X-ray CT also detected similar changes in the pixel concentration in the regenerated region and the regenerated bone volume, clarifying that bFGF promoted bone regeneration. The relative aluminum concentration measured by photodensitometry and the pixel concentration measured by microfocus X-ray CT were correlated. It was revealed that microfocus X-ray CT can non-invasively evaluate regenerated bone, and is capable of quantitative and 3 -dimensional analyses. These findings suggested that microfocus X-ray CT is useful for the assessment of regenerated bone in the clinical application of regenerative medical methods.
