IN-VITRO ASSESSMENT OF THE RELATIONSHIP BETWEEN ACOUSTIC PROPERTIES AND BONE MASS DENSITY OF THE CALCANEUS BY COMPARISON OF ULTRASOUND PARAMETRIC IMAGING AND QUANTITATIVE COMPUTED-TOMOGRAPHY

This in vitro study aimed to add new experimental evidence to clarify the relation between acoustic properties of bone and bone mineral dens ity (BMD) of the human calcaneus, Parametric images of normalized broa dband ultrasonic attenuation (nBUA) and ultrasound bone velocity (UBV) were compared with quantitative computed tomography (QCT) images of t he calcaneus, The experimental protocol was designed to control the di fferent potential sources of error in acoustic measurements, including the shape and thickness of the samples, intervening soft tissues and cortical bone, boundary effects, and variation in location of the regi ons of interest (ROIs) analyzed by ultrasound and X-ray, The present s tudy was based on bone specimens from calcaneus removed from 15 cadave rs (six male and nine female donors ranging from 69 to 89 years of age ), Immersion ultrasonic measurements were performed in the through-thi ckness direction at normal incidence using a pair of focused broadband 0.5-MHz transducers, QCT of the specimens was performed using standar d 10-mm-thick slices with the Cann-Genant calibration standard. Identi cal, site-matched ROIs were selected for quantitative analysis on the three images, The pattern of acoustic parameters was similar to that o f BMD with QCT, The relationships between nBUA and BMD (r(2) = 0.75), between UBV and BMD (r(2) = 0.88) and between nBUA and UBV (r(2) = 0.8 4) were highly significant (p < 10(-4)), From this study, it appears t hat ultrasound parameters as measured with current transmission techni ques reflect mainly bone quantity and only reflect microarchitecture t o a small extent and that BUA and UBV reflect the same bone property. (C) 1997 by Elsevier Science Inc.