Department of Physics, University of Jyväskylä, PO BOX 35 (YFL), 40014 Jyväskylä, Finland.
Osteoporos Int. 2011 Apr;22(4):1103-13. doi: 10.1007/s00198-010-1273-7. Epub 2010 Jun 25.
Axial transmission velocity of a low-frequency first arriving signal (V (LF)) was assessed in the radius and tibia of 254 females, and compared to site-matched pQCT measurements. V (LF) best correlated with cortical BMD, but significantly also with subcortical BMD and cortical thickness. Correlations were strongest for the radius in postmenopausal females.
Ultrasonic low-frequency (LF; 0.2-0.4 MHz) axial transmission, based on the first arriving signal (FAS), provides enhanced sensitivity to thickness and endosteal properties of cortical wall of the radius and tibia compared to using higher frequencies (e.g., 1 MHz). This improved sensitivity of the LF approach has not yet been clearly confirmed by an in vivo study on adult subjects. The aims of the present study were to evaluate the extent to which LF measurements reflect cortical thickness and bone mineral density, and to assess whether an individual LF measurement can provide a useful estimate for these bone properties.
Velocity of the LF FAS (V (LF)) was assessed in the radius and tibia shaft by a new ultrasonometer (CV(RMS) = 0.5%) in a cross-sectional study involving 159 premenopausal (20-58 years) and 95 postmenopausal females (45-88 years). Site-matched volumetric total bone mineral density (BMD), cortical bone mineral density (CBMD), subcortical bone mineral density (ScBMD) and cortical thickness (CTh) were assessed using pQCT.
For the postmenopausal females, V (LF) correlated best with CBMD in the radius (R = 0.850, p < 0.001), but significantly also with ScBMD and CTh (R = 0.759 and R = 0.761, respectively; p < 0.001). Similar trends but weaker correlations were observed for the tibia and for the premenopausal women.
The LF assessment, with an optimal excitation frequency, thus provided good prediction of both cortical thickness and subcortical bone material properties. These results suggest that the LF approach does indeed have enhanced sensitivity for detecting osteoporotic changes that occur deep in the endosteal bone.
评估低频（0.2-0.4 MHz）轴向传输的第一到达信号（FAS）的轴向传输速度（V（LF））在 254 名女性的桡骨和胫骨中的表现，并将其与部位匹配的 pQCT 测量结果进行比较。V（LF）与皮质骨密度相关性最佳，但与皮质下骨密度和皮质厚度也显著相关。在绝经后女性中，桡骨的相关性最强。
与使用更高频率（例如 1 MHz）相比，基于第一到达信号（FAS）的超声低频（LF；0.2-0.4 MHz）轴向传输对桡骨和胫骨皮质壁的厚度和骨内表面特性具有更高的敏感性。这种 LF 方法的改进敏感性尚未通过对成年受试者的体内研究得到明确证实。本研究的目的是评估 LF 测量在多大程度上反映皮质厚度和骨密度，并评估个体 LF 测量是否可以提供对这些骨特性的有用估计。
通过新超声仪（CV（RMS）= 0.5%）在横断面研究中评估桡骨和胫骨骨干的 LF FAS 速度（V（LF）），该研究涉及 159 名绝经前（20-58 岁）和 95 名绝经后女性（45-88 岁）。使用 pQCT 评估部位匹配的总体骨矿物质密度（BMD）、皮质骨矿物质密度（CBMD）、皮质下骨矿物质密度（ScBMD）和皮质厚度（CTh）。
对于绝经后女性，V（LF）与桡骨中的 CBMD 相关性最佳（R = 0.850，p < 0.001），但与 ScBMD 和 CTh 也显著相关（R = 0.759 和 R = 0.761，分别；p < 0.001）。对于胫骨和绝经前女性，观察到类似的趋势，但相关性较弱。
最佳激励频率的 LF 评估可很好地预测皮质厚度和皮质下骨材料特性。这些结果表明，LF 方法确实对检测发生在骨内表面深部的骨质疏松性变化具有更高的敏感性。
