New point-of-care calcaneal ultrasound densitometer (Osteosys BeeTLE) compared to standard dual-energy X-ray absorptiometry (DXA)

Dual-energy X-ray absorptiometry (DXA) represents the gold standard for measuring bone mineral density (BMD). However, its size and bulkiness limit its use in mass screening. Portable and easily accessible instruments are more suitable for this purpose. We conducted a study to assess the repeatability, sensitivity, accuracy, and validation of a new ultrasound densitometer for the calcaneus (OsteoSys BeeTLe) compared to standard DXA. BMD (g/cm 2 ) was measured at the femoral and lumbar spine levels using DXA (Discovery Acclaim (Hologic, Waltham, MA, USA) or Lunar Prodigy (GE Healthcare, Madison, WI, USA) devices). Bone Quality Index (BQI, a dimensionless measure of bone quality derived from measures of SOS [Speed Of Sound] and BUA [broadband ultrasound attenuation]) was measured with OsteoSys BeeTLe. The Bland–Altman test and simple linear regression were used to evaluate the association between values measured with the two instruments. Additionally, the ability of the T-score calculated with BeeTLe to identify patients with previous osteoporotic fractures was tested using ROC curves. A total of 201 patients (94.5% females) with a mean age of 62.1 ± 10.2 were included in the study. The BeeTLe instrument showed a coefficient of variation (CV, in 75 repeated measurements) of 1.21%, which was not statistically different from the CV of DXA (1.20%). We found a significant association between BQI and BMD at the femoral neck (r2 = 0.500, p < 0.0001), total femur (r2 = 0.545, p < 0.0001), and lumbar spine (r2 = 0.455, p < 0.0001). T-scores bias were 0.215 (SD 0.876), 0.021 (SD 0.889) and 0.523 (SD 0.092), for femoral neck, total hip and lumbar spine respectively. AUC for discriminating fracture and non-fractured patients were not significantly different with OsteoSys BeeTLe and standard DXA. In this preliminary study, BeeTLe, a new point-of-care ultrasound densitometer, demonstrated good repeatability and performance similar to DXA. Therefore, its use can be proposed in screening for osteoporosis.