Prospective discrimination of vertebral fractures by axial transmission ultrasound using optimized first arriving signal velocity measurements

The objective of this study is to assess the clinical performance of a novel bi-directional axial transmission (BDAT) ultrasound prototype. The speed of sound of the first arriving signal (V
_FAS
) was measured at the radius (single site) and at the tibia (two sites) of 51 post-menopausal females. An optimized V
_FAS
measurement protocol was introduced to reduce the clinical measurement time (from 30 to 10 minutes) by maintaining the robustness of the former method. The optimized protocol was efficient and showed excellent discrimination performance: the highest areas under the ROC curves (AUC) were found for V
_FAS
radius (OR: 3.54; AUC: 0.81) and V
_FAS
tibia medial surface (MS) (OR: 4.10; AUC: 0.81). Dual energy x-ray absorptiometry (DXA) at the lumbar spine exhibited similar fracture discrimination power (OR: 1.89; AUC: 0.81) compared to the ultrasonic method.