Multisite ultrasound axial transmission study in postmenopausal women using optimized first arriving signal velocity measurements

The objective of this study is to assess the clinical performance of a novel ultrasound bidirectional axial transmission (BDAT) prototype. The speed of sound of the first arriving signal (V
FAS
) was measured in the radius and tibia of 58 postmenopausal females. An optimized V
FAS
measurement protocol was introduced in order to reduce the clinical measurement time and increase the robustness in particular for patients with pronounced body mass index (BMI). The optimized protocol was efficient and showed excellent discrimination performance: the highest area under the ROC curve (AUC) was found for V
FAS
radius (OR=2.60; AUC=0.89). In comparison, dual energy x-ray absorptiometry (DXA) values of the lumbar spine (OR=1.89; AUC=0.87) exhibited comparable fracture discrimination performance compared to the ultrasonic method.