Yubing Xu

Impact of Age, Gender, and Body Composition on Bone Quality in an Adult Population From the Middle Areas of China

Identifying modifiable factors that influence bone status during adulthood to maximize bone quality is a potential primary strategy in the prevention of osteoporosis in later life. We investigated the impact of body height, body weight, body mass index, and body composition on calcaneal bone characteristics as measured with quantitative ultrasound in 441 Chinese adults (238 women) aged 20-55 yr from the middle areas of China. Body composition, including fat-free mass (FFM), muscle mass, and fat mass were obtained by bioelectrical impedance analysis. Bivariate correlation analysis demonstrated a significant negative correlation between age and broadband ultrasound attenuation (BUA), speed of sound (SOS), and stiffness index (SI) both in men (r = -0.177, p < 0.05; r = -0.499, p < 0.001; r = -0.530, p < 0.001, respectively) and women (r = -0.344, p < 0.001; r = -0.336, p < 0.001; r = -0.369, p < 0.001, respectively). Body height, body weight, FFM, and muscle mass had positive correlations with BUA, SOS, and SI in both genders, with FFM having the strongest correlation with BUA, SOS, and SI in men (r = 0.351, p < 0.001; r = 0.391, p < 0.001; r = 0.406, p < 0.001, respectively) and women (r = 0.331, p < 0.001; r = 0.288, p < 0.001; r = 0.324, p < 0.001, respectively). Fat mass had a positive correlation with BUA (r = 0.331, p < 0.001), SOS (r = 0.288, p < 0.001), and SI (r = 0.324, p < 0.001) in women, which was not found in men. Multivariate regression analysis revealed that, in both genders, FFM was a positive predictor for all 3 quantitative ultrasound variables.

A region-matching method for pulse transit time estimation: potential for improving the accuracy in determining carotid femoral pulse wave velocity

Carotid femoral pulse wave velocity (cfPWV) is the ‘gold standard’ for assessment of arterial stiffness. The reliability of cfPWV measurement depends on the estimation of pulse transit time (PTT). This study aimed to validate a region-matching method for determining PTT and cfPWV against the existing ‘foot-to-foot’ methods. A cohort of 81 subjects (33 males and 48 females) aged 25–80 (45.1±15.7 years) were studied. PTTs were estimated by the region matching and ‘foot-to-foot’ methods (‘diastole minimum’, ‘maximum first derivative’, ‘maximum second derivative’ and ‘tangent intersection’ methods) with manual identification as the reference method and were subsequently used to calculate cfPWV. In a subgroup of 30 individuals, the measurements were repeated after 1 h. There were excellent correlations between cfPWV obtained by the reference method and all the estimated methods (r>0.9, P<0.001 for all), except the diastole minimum method (r=0.793, P<0.001). The region-matching method yielded cfPWV with a better accuracy (mean difference=−0.161 m s−1, limits of agreement: −0.79 to 0.46 m s−1) and repeatability (mean difference=−0.228 m s−1, intraclass correlation coefficient=0.957) comparing with the ‘foot-to-foot’ methods. These results demonstrate that the proposed region-matching method is more accurate and suitable for PTT estimation and cfPWV measurement.

Reducing temperature influence on dry quantitative ultrasound bone assessment with constant temperature control.

Nowadays, ultrasonic bone assessment is increasingly being used to assess bone status. Therefore, the purpose of this study was to enhance the precision of ultrasonic bone assessment by reducing the influence of temperature in a dry, gel coupled transducer system. A warm airflow generator was designed to make the measurement temperature constant (35±1°C). Thirty people were recruited for the evaluation of in-vivo performance. The short-term precision was performed 10 times with repositioning during a consecutive measurement session within 20min. It was expressed as root-mean square average of coefficient of variation, which is abbreviated for CV(RMS). The CV(RMS) was 3.84% for broadband ultrasound attenuation, and 0.30% for speed of sound. The Pearson correlations between gel coupled transducer system and dual energy X-ray absorptiometry (DEXA) were 0.808 (p<0.001) for broadband ultrasound attenuation, and 0.586 (p<0.005) for speed of sound. The result showed the high performance of reproducibility and the significant (p<0.005) correlations with DEXA in the dry, gel coupled transducer system.

Correlation between ultrasonic power spectrum and bone density on the heel

HIGHLIGHTSThree parameters from normalized power spectrum were chosen and be evaluated the correlation with the lumbar spine BMD.One of parameters (amplitude for principle frequency, APF) has been proved a significant correlation with BMD.A multiple regression model including all three QUS variables (BUA, SOS and APF) was somewhat more predictive of BMD than a model including only BUA and SOS. ABSTRACT The purposes of this paper were to evaluate the correlation between ultrasonic power spectrum and bone density and to extract the effectiveness of parameters from power spectrum for evaluating bone density. A total of 50 persons 24–72 years of age were recruited. All study participants underwent bone mineral density (BMD) measurements of the lumbar spine (vertebral levels L1–L4). The participants also underwent calcaneal measurements to determine ultrasonic power spectrum with central frequencies of 0.5 MHz. Three parameters from normalized power spectrum, called principle frequency (PF), frequency band (FB), and amplitude for principle frequency (APF), were chosen and be evaluated the correlation with the lumbar spine BMD. The correlation coefficient of PF, FB and APF with BMD was r = −0.48 (p < 0.001), r = 0.48 (p < 0.001), and r = −0.71 (p < 0.001), respectively. The results showed that the correlation between APF and BMD was better than the correlation among PF, FB and BMD, and APF have a significant correlation with BMD. In conclusion, the correlations among the parameters of ultrasonic power spectrum and BMD are significant, and especially APF performs better than PF and FB in evaluating bone density of participants. These results suggest that ultrasonic power spectrum may contain substantial information not already contained in BUA and SOS. A multiple regression model including all three QUS variables was somewhat more predictive of BMD than a model including only BUA and SOS.

Analysis of Forced Expiratory Flow Signals Using the New Luus–Jaakola Optimization Procedure

Objective: The aim of this study was to estimate forced vital capacity (FVC) by analyzing incomplete forced expiratory flow-time (FEFT) curves using the new Luus-Jaakola (NLJ) optimization procedure. Methods: Complete FEFT curves from 90 subjects with and without respiratory disease were used to validate the method, and its application performance was evaluated by FEFT curves containing incomplete curves from nine obstructive patients. First, a lumped parameter model of the FEFT curve, taking FVC as one of the model parameters, is chosen. The 0- 1 s, 0-1.5 s, . . . , 0-6 s curves chosen from the accepted FEFT curves are, respectively, taken as the local system observations. Then, the NLJ optimization procedure was used to get the estimate of FVC (FVCest) by estimating the model parameters. Finally, FVCest was compared with the measured FVC (FVCmea). Results: The difference between FVCest and FVCmea decreased with the lengths of observed curves increasing. When the lengths of observed curves reached 3 s, the mean difference (±SD) between FVCest and FVCmea was -11 ± 58 mL. Estimated FVC derived from the incomplete curves were close to FVC from accepted maneuvers. Conclusion: The method can be used to estimate FVC by analyzing an incomplete FEFT curve, providing the length of the curve is more than 3 s. Significance: This method can help the subjects who cannot complete the forced expiratory maneuver to provide a reliable estimate of FVC and also can be used to analyze the unacceptable spirometry because of early termination of exhalation.