Development of a QUS Device to Evaluate Deterioration of Cortical Bone: Verification by HR-pQCT and Measurements in Healthy Individuals and Dialysis Patients.

INTRODUCTION: The objectives of this study were to identify what is reflected in cortical speed of sound (cSOS) measured by a cortical quantitative ultrasound (cortical QUS) device we have developed, and to investigate cSOS measurements in healthy individuals and dialysis patients. METHODS: The cSOS and the SOS were measured by cortical QUS and conventional QUS in 20 volunteers, and the correlations between these measurements and areal bone mineral density measured by dual-energy X-ray absorptiometry and bone microstructural parameters on high-resolution peripheral quantitative computed tomography were analyzed. The cSOS and the SOS were measured in 91 young adults (47 men, 44 women), 64 elderly people (30 men, 33 women), and 64 dialysis patients (33 men, 31 women). The period of hemodialysis and intact parathyroid hormoneevels were also investigated in the dialysis patients. RESULTS: cSOS was correlated with cortical tissue mineral density (tibia: r = 0.74, radius: r = 0.72) on high-resolution peripheral quantitative computed tomography, reflecting the degree of minaralization and microporosity of cortical bone. There was no correlation with the thickness of cortical bone, suggesting that it measured the bone quality rather than bone mass. Elderly women had lower cSOS than young adults (3865 ± 74 vs 3971 ± 63 m/s, p < 0.01). Many of dialysis patients showed very low cSOS and it was related to higher intact parathyroid hormone levels (male: ß = -0.67, female: ß = -0.60). CONCLUSIONS: Our cortical QUS device is capable of evaluating the qualitative degradation of cortical bone, which cannot be assessed by conventional QUS, and its use in combination with conventional QUS may provide a better understanding of fracture risk.