Broadband ultrasound attenuation imaging: influence of location of region of measurement

The aim of the study was to investigate the effect of three different regio ns of interest (ROIs) varying in size and shape on broadband ultrasound att enuation (BUA) measurements of the calcaneus. Two hundred and sixty-five po stmenopausal Caucasian women participated in this study. In 43 women osteop orotic fractures were documented on spinal radiographs. Bone mineral densit y (BMD) measurements of the lumbar spine and the femur were made using dual -energy X-ray absorptiometry. BUA measurements were obtained at a circular ROI automatically determined by the imaging system (ROIc), at a manually tr aced irregular ROI encompassing the posterior part of the calcaneus (ROIi), and at an anatomical square ROI located in the posterior part of the calca neus (ROIs). Reproducibility was better in ROIc than in ROIi and ROIs. High correlations were found between BUA measurements with ROIc and ROIs (r = 0 .981, P < 0.0001) as well as between those with ROI, and ROIi (r = 0.965, P < 0.0001). There were no significant differences between the correlations of BUA with axial BMD at ROIc compared with ROIi and ROIs. No significant d ifference was found between the areas under the ROC curve at ROIi, ROIc, an d ROIi, for women with fractures. The results show that superior reproducib ility makes ROIc the most appropriate region of BUA measurement in a compar ison with ROIi and ROIs.