FRACTAL ANALYSIS OF BONE TEXTURE ON OS CALCIS RADIOGRAPHS COMPARED WITH TRABECULAR MICROARCHITECTURE ANALYZED BY HISTOMORPHOMETRY

Microarchitecture of trabecular bone is an important determinant of bo ne fragility; to date, its evaluation requires bone biopsy with histom orphometry analysis. Methods of noninvasive characterization of trabec ular bone microarchitecture are in development and we have developed a nd validated a bone texture analysis applied to bone radiographs and b ased on fractal geometry. The aim of our study was to compare this fra ctal analysis of trabecular bone texture on radiographs to the trabecu lar microarchitecture analyzed by bone histomorphometry on os calcis b iopsies. Thirty eight ossa calcis from 19 human cadavers were studied. Fractal analysis of the trabecular bone of os calcis radiographs was performed by the maximum likelihood estimator following the fractional brownian motion model. The ossa calcis were dissected, then transcort ical biopsy cores focused on the fractal analysis region of interest w ere obtained. Structural and connectivity parameters were measured wit h both automatic and semiautomatic analyzers. We have found a signific ant relationship between the fractal Hmean parameter and structural hi stomorphometric indices; the best correlation was found with trabecula r separation (r = -0.55; P = 0.0004). Based on a stepwise regression a nalysis, trabecular spacing and trabeculae number together would expla in 38% of the variance of the fractal parameter. Although the relation ship with connectivity indices was poor, our fractal analysis of os ca lcis trabecular bone texture on radiographs seemed to partially reflec t the trabecular bone microarchitecture.