Estimation of in Vivo Bone Mineral Density (BMD) and Shape Characterization for Diagnosing Osteoporosis by Ultrasonic Inspection

Abstract

A new method for estimating in vivo bone mineral density (BMD ) and characterizing the shape of cancellous bone has been proposed using the results of ultrasonic inspection for the diagnosis of osteoporosis. The method is based on two-dimensional bone area fraction S (percent bone area between bone and bone marrow) calculated from the difference in the speed of ultrasonic wave propagation through cancellous bone. It was shown that the two-dimensional area fraction of a heel bone gives a good relationship to the BMD by DXA (dual energy x-ray absorptiometry) testing of human heel bone (calcaneus) and spine (vertebrae lumbar), as expressed by the relation, BMD (g/cm2 ) = 0.0167S for heel bone (r = 0.83), and BMD (g/cm2 ) = 0.0254S + 0.123 for the spine (r = 0.77). Shape characterization is based on the image simulation procedure employing eight random variables from a computer and the statistical results of fractal analysis for numerous cancellous bone patterns. We also demonstrate the validity of the shape characterization technique using autopsy specimens as a diagnostic tool for osteoporosis.