Relationships of ultrasonic backscatter with ultrasonic attenuation, sound speed and bone mineral density in human calcaneus

Ultrasonic attenuation and sound speed have been investigated in trabecular bone by numerous authors. Ultrasonic backscatter has received much less attention. To investigate relationships among these three ultrasonic parameters and bone mineral density (BMD), 30 defatted human calcanei were investigated in vitro. Normalized broadband ultrasonic attenuation (nBUA), sound speed (SOS), and logarithm of ultrasonic backscatter coefficient (LBC) were measured. Bone mineral density was assessed using single-beam dual energy x-ray absorptiometry (DEXA). The correlation coefficients of least squares linear regressions of the three individual ultrasound (US) parameters with BMD were 0.84 (nBUA), 0.84 (SOS) and 0.79 (LBC). The 95% confidence intervals for the correlation coefficients were 0. 69-0.92 (nBUA), 0.68-0.92 (SOS) and 0.60-0.90 (LBC). The correlations among pairs of US variables ranged from 0.63-0.79. Variations in nBUA accounted for r(2) = 62% of the variations in LBC. Variations in SOS accounted for r(2) = 40% of the variations in LBC. These results suggest that ultrasonic backscattering properties may contain substantial information not already contained in nBUA and SOS. A multiple regression model including all three US variables was somewhat more predictive of BMD than a model including only nBUA and SOS.     

Effect of trabecular orientation on mechanical resistance and ultrasound propagation in specimens of equine vertebrae

Osteoporosis involves alterations, not only in density, but also in the architectural organisation of the bone; in particular, trabecular orientation, following the skeletal load directions, lends a high degree of stiffness to the whole bone. We investigated the relationship between trabecular orientation, density, stiffness and ultrasound (US) propagation in two orthogonal directions (par. = parallel to, and ort. = orthogonal to the main orientation of the trabeculae) in cylindrical equine bone specimens (thoracic vertebrae) where a preferential orientation is present. A total of 15 cylinders were progressively decalcified with 0.2 mol/L ethylenediaminetetraacetic acid (EDTA). At different levels of decalcification, we measured the apparent density (g/cm³), bone mineral density or BMD (g/cm²), stiffness coefficient (MPa) and various US parameters. Before decalcification, stiffness values were the same in all directions. As the decalcification proceeded, the stiffness declined and, at low BMD values, it was significantly different in the two directions, being the highest in the par. one. Different behaviours of US parameters were observed in the two directions: SoS (speed of sound) was closely related to apparent density, BMD and stiffness in the par. direction (r = 0.88, 0.92 and 0.88, respectively, p < 0.0001). In the ort. direction, no significant association has been found between SoS and apparent density, BMD or stiffness. In the same experimental setup, US fast wave amplitude (FWA) was related to apparent density and BMD in the par. direction (r = 0.72 and 0.67, respectively, p < 0.0001) and in the ort. direction (r = 0.83 and R = 0.84 respectively, p < 0.0001). FWA was also correlated to stiffness in both directions (r = 0.61 par.; 0.81 ort., p < 0.0001). These results show that trabecular orientation strongly influences both mechanical properties of bone and US propagation. Furthermore, we found that US parameters can be predictors of mechanical properties of the bone independent of bone density. (E-mail: fcavani@unimore.it)     

Dual-energy digital radiography in the assessment of bone mechanical properties

At present, bone fragility and fracture risk are estimated with bone mineral density (BMD), measured by dual-energy x-ray absorptiometry (DXA). It is known that DXA-based BMD (BMD(DXA)) has a relationship with mechanical characteristics of bone. Dual-energy digital radiography (DEDR) has also been shown to be a potential method to determine BMD, but the ability of DEDR-based BMD (BMD(DEDR)) to predict bone mechanical properties is not yet known. In this study, we investigated the ability of BMD(DEDR) to predict the mechanical characteristics of bone. Reindeer femora (N = 50) were imaged at two different energies (79 and 100 kV(p)) using a clinical digital radiography system. BMD was determined in four regions from these images using the DXA calculation principle. Femora were mechanically tested using axial loading configuration. Mechanical parameters were correlated with the BMD(DEDR) and BMD(DXA) of the femoral neck (FNBMD(DEDR) and FNBMD(DXA)). FNBMD(DEDR) and FNBMD(DXA) both correlated moderately with mechanical parameters. The highest correlations were found with maximal load (r = 0.53 and r = 0.65, p < 0.01, respectively). No statistically significant differences were found between the correlation coefficients when comparing the FNBMD(DEDR) or FNBMD(DXA) values and mechanical parameters. The correlation coefficient between BMD(DEDR) and BMD(DXA) varied between r = 0.56 and 0.86 (p < 0.01) in different regions of the upper femur. In conclusion, BMD(DEDR) predicts the mechanical parameters of reindeer bone with similar accuracy as BMD(DXA).     

Estimation of wrist fracture load using phalangeal speed of sound: an in vitro study

This study aimed to evaluate the ability of speed of sound (SOS) measured at the phalanges to estimate simulated wrist fracture load and stress. SOS was measured along the proximal phalanges of the second, third and fourth fingers using an ultrasound (US) system operating in axial transmission mode. The bone mineral density (BMD) of the radius and the phalanges was also measured with quantitative computed tomography (QCT) and dual x-ray absorptiometry (DXA), and the combined cortical thickness (CCT) of the phalanges was measured from hand radiographs. After the measurements were completed, the radius was excised from the cadaver, embedded in polymethylmethacrylate and tested to failure on a servohydraulic testing machine. The configuration of the radius was chosen to simulate a fall onto the hand. Linear regression analysis showed a highly significant correlation between SOS (r = 0.76–0.94, p < 0.001), CCT (r = 0.86–0.90, p < 0.001) and BMD (r = 0.92–0.96, p < 0.0001) in the three proximal phalanges measured. SOS, BMD and CCT were significant predictors of fracture load (r = 0.60–0.69, p < 0.03) and stress (r = 0.65–0.77, p < 0.02). Cortical area and bone mineral content (BMC) of the radius were consistently higher predictors of fracture load (r = 0.76–0.82, p < 0.01 for area and R = 0.78–0.88, p < 0.01 for BMC) than BMD. The correlation of BMC and area was poorer with fracture stress. In a step-wise regression analysis using both phalangeal BMD and SOS, only SOS remained a significant predictor of fracture stress. In forward stepwise regression analysis, both cortical area and SOS were entered into the regression model to estimate fracture load. Only SOS remained significant in the model for estimating fracture stress. Phalangeal BMD was only entered in the combined model with the cortical area at the 4% site (r = 0.84, p = 0.002). Phalangeal SOS is a useful parameter in the assessment of bone status of the radius.     

Estimation of wrist fracture load using phalangeal speed of sound: an in vitro study

This study aimed to evaluate the ability of speed of sound (SOS) measured at the phalanges to estimate simulated wrist fracture load and stress. SOS was measured along the proximal phalanges of the second, third and fourth fingers using an ultrasound (US) system operating in axial transmission mode. The bone mineral density (BMD) of the radius and the phalanges was also measured with quantitative computed tomography (QCT) and dual x-ray absorptiometry (DXA), and the combined cortical thickness (CCT) of the phalanges was measured from hand radiographs. After the measurements were completed, the radius was excised from the cadaver, embedded in polymethylmethacrylate and tested to failure on a servohydraulic testing machine. The configuration of the radius was chosen to simulate a fall onto the hand. Linear regression analysis showed a highly significant correlation between SOS (r = 0.76–0.94, p < 0.001), CCT (r = 0.86–0.90, p < 0.001) and BMD (r = 0.92–0.96, p < 0.0001) in the three proximal phalanges measured. SOS, BMD and CCT were significant predictors of fracture load (r = 0.60–0.69, p < 0.03) and stress (r = 0.65–0.77, p < 0.02). Cortical area and bone mineral content (BMC) of the radius were consistently higher predictors of fracture load (r = 0.76–0.82, p < 0.01 for area and R = 0.78–0.88, p < 0.01 for BMC) than BMD. The correlation of BMC and area was poorer with fracture stress. In a step-wise regression analysis using both phalangeal BMD and SOS, only SOS remained a significant predictor of fracture stress. In forward stepwise regression analysis, both cortical area and SOS were entered into the regression model to estimate fracture load. Only SOS remained significant in the model for estimating fracture stress. Phalangeal BMD was only entered in the combined model with the cortical area at the 4% site (r = 0.84, p = 0.002). Phalangeal SOS is a useful parameter in the assessment of bone status of the radius.     

Acoustic properties of trabecular bone--relationships to tissue composition

In osteoporosis, changes in tissue composition and structure reduce bone strength and expose it to fractures. The current primary diagnostic technique, i.e., dual energy X-ray absorptiometry, measures areal bone mineral density (BMD) but provides no direct information on trabecular structure or organic composition. Although still poorly characterized, ultrasound techniques may bring about information on bone composition and structure. In this study, relationships of 2.25-MHz ultrasound speed, attenuation, reflection and backscattering with composition of human trabecular bone (n=26) were characterized experimentally, as well as by using numerical analyses. We also determined composition of the trabecular sample (fat and water content, bone volume fraction) and that of the calcified matrix (mineral, proteoglycan and collagen content of trabeculae). In experimental analyses, bone volume fraction and mineral content of the calcified matrix were the only determinants of BMD. Further, bone volume fraction served as the strongest determinant of ultrasound parameters (r=0.51-0.87). In numerical simulations, density and mechanical properties of the calcified matrix systematically affected ultrasound speed, attenuation, reflection and backscattering. However, partial correlation coefficients revealed only low associations(|r|相似文献   

Ultrasound Backscatter Imaging Provides Frequency-Dependent Information on Structure,Composition and Mechanical Properties of Human Trabecular Bone

The strength as well as the acoustic properties of trabecular bone are determined by its structure and composition. Consequently, tissue structure and compositional properties also affect the ultrasound propagation in bone. The diagnostic potential of ultrasound has not been fully exploited in clinical quantitative ultrasound devices. The aim of this study was to investigate the ability of quantitative ultrasound pulse-echo imaging, conducted over a broad range of frequencies (1 to 5 MHz), to predict the mechanics, composition and microstructure of trabecular bone. Ultrasound reflection and backscatter parameters correlated significantly with the ultimate strength of the trabecular bone and the bone volume fraction (r = 0.76–0.90, n = 20, p < 0.01). Ultrasound backscatter associated significantly (independently of bone structure or mineral content) with the collagen content of the bone matrix (r = 0.75, r_adjusted = 0.66, p < 0.01). Interestingly, the applied ultrasound frequency seemed to relate the sensitivity of ultrasound backscatter to different properties of trabecular bone. At frequencies ranging from 1 to 3.5 MHz, the ultrasound backscatter associated significantly with the tissue mechanical and structural parameters. At 5 MHz, the composition of the bone matrix was a more significant determinant of the measured backscatter. This study provides useful information for optimizing the use of pulse-echo measurements, and thereby further emphasizes the diagnostic potential of the ultrasound backscatter measurements of trabecular bone.     

Changes in calcanean bone mineral occurring spontaneously and during hormone replacement therapy in early post-menopausal women.

The spontaneous calcanean bone loss occurring in healthy early post-menopausal women and the effect of two hormone replacement therapies (HRT's) were investigated in a longitudinal study. There was no difference between the right and left calcanean BMC or BMD (p > 0.15). The spontaneous bone loss was similar at all the skeletal sites measured, with a mean spontaneous loss in calcanean BMD of 1.6% over one year. Both HRT's significantly (p < 0.01) prevented the bone loss from all skeletal sites irrespective of the weight-bearing or content of trabecular bone, and (for the weight-bearing bones) there was even a gain in calcanean BMC and BMD and spinal BMD (p < 0.01). Bone mineral of the calcaneus and the spine correlated equally to body weight (r approximately 0.4, p < 0.001), whereas bone mineral in the forearm was not correlated to body weight. The correlations between the changes in bone mineral at the sites measured were all significant (r approximately 0.2-0.4).     

Bone marrow influences quantitative ultrasound measurements in human cancellous bone

Quantitative ultrasound (QUS) transmission and backscatter measurements were made in 46 human cancellous bone specimens from the calcaneus. All QUS measurements were made at 35 degrees C, initially with marrow filling the pores and then repeated after substituting water for marrow. Bone mineral density (BMD) was determined using x-ray absorptiometry. Marrow significantly decreased ultrasound (US) velocity, but increased attenuation, attenuation slope and backscatter (p < 0.001 for all) compared to the water-saturated state. The impact of marrow on QUS measurements was greater at lower BMD values (p < 0.05), and was greater in women than in men (p < 0.05). QUS measurements in marrow-saturated specimens correlated less strongly with BMD than did corresponding measurements in water-saturated specimens (p < 0.05), consistent with interspecimen marrow heterogeneity. These data indicate that the potential impact of marrow should be considered when interpreting clinical QUS measurements. Understanding and exploiting these effects could lead to novel approaches for ultrasonic characterisation of both bone and marrow.     

Quantitative ultrasound and peripheral bone densitometry in patients with genetic disorders

The aim of the study was comparison of quantitative ultrasound and densitometric peripheral measurements in subjects with genetic disorders. The study included 52 subjects (35 boys and 17 girls) in mean age 13.1 +/- 4.8 y. Patients with following disorders were evaluated: Down syndrome (n = 21), Martin-Bell syndrome (n = 14) and other (n = 17). There were no additional factors potentially influencing bone metabolism. Bone status was assessed by quantitative ultrasound at the hand phalanges using DBM Sonic 1200 (IGEA, Italy), which measures amplitude-dependent speed of sound (Ad-SoS [m/s]) and bone densitometry at the calcaneus and forearm by the use of PIXI (GE, USA), which measures bone mineral density (BMD, g/cm2). Ad-SoS correlated significantly with forearm and calcaneus BMD in the whole group (r = 0.66, p < 0.000001 and r = 0.51, p < 0.0001, respectively), in females (r = 0.58, p < 0.05 and r = 0.5, p < 0.05) and in males (r = 0.70, p < 0.000001 and r = 0.54, p < 0.001). Calcaneus BMD correlated with wrist BMD in the whole group, in females and males: r = 0.66, p < 0.000001, r = 0.67, p < 0.01 and r = 0.75, p < 0.0001, respectively. These coefficients of correlation were compared and did not reveal significant differences in the whole group and in the gender subgroups. ROC analysis of Ad-SoS values versus calcaneus and forearm BMD showed area under curve 0.89 for forearm BMD and 0.79 for calcaneus BMD (subjects with Ad-SoS T-score below -3.2 were considered as abnormal). Age correlated significantly with Ad-SoS, forearm and calcaneus BMD (r ranged from 0.53 to 0.9, p from 0.05 to 0.000001). In all patients and males, age more strongly influenced Ad-SoS than calcaneus BMD (p < 0.05). Also, body weight and height correlated significantly with Ad-SoS, forearm and calcaneus BMD, except for correlation between forearm BMD and height in female patients (r from 0.58 to 0.84, p < 0.05). Generally, in multiple stepwise regression analysis of age and body size on skeletal parameters, age had positive influence, and body size was a positive or a negative factor. In conclusion, both quantitative ultrasound and peripheral densitometry may be recommended for the assessment of skeletal status in subjects with genetic disorders, although measurements of phalanges seem to be more sensitive for detecting age-related bone changes.     

Ability of ultrasound bone profile score (UBPS) to discriminate between fractured and not fractured osteoporotic women

In this study, we evaluated the ability of different quantitative ultrasound (QUS) parameters (speed of sound, SOS, coefficient of variation, CV, = 0.34% and broadband ultrasound (US) attenuation, BUA, CV = 3.25% measured at the heel by an Hologic Sahara unit; Ad-Sos and ultrasound bone profile score (UBPS) at the proximal phalanges by an Igea DBM Sonic 1200 unit, Ad-Sos CV = 0.57%) to detect differences between osteoporotic patients with vertebral fractures and osteoporotic patients without fractures. We examined 87 women with primary osteoporosis: 53 women with femoral neck bone mineral density (BMD) T scores less than -2.5 SD and no vertebral fractures and 34 women with one or more vertebral fractures, regardless of T score values. Considering all the patients together, the correlations between QUS parameters and BMD resulted in statistical significance (p < 0.05) only for BUA and femoral neck BMD. Lumbar and femoral neck BMD did not statistically differ between the two groups, while UBPS, which is a quality control of measurement and is correlated with bone quality, was significantly higher in women without fractures than those with fractures; the other QUS parameters were not statistically different. Our data indicate that, among QUS parameters, only UBPS is able to detect differences among osteoporotic patients with and without vertebral fractures.     

热固耦合式超声骨强度仪的可重复性及相关性研究

目的:评估一款国产热固耦合式超声骨强度仪的可重复性和有效性。方法:选择11名志愿者,用该仪器测得右跟骨的两个超声参数,分别是超声速度(SOS)和宽带超声衰减(BUA),计算每个参数的变异系数均方根百分比(CVRMS%),评估该仪器的短期可重复性;选择18名志愿者,用类似的方法评估该仪器的中期可重复性;选择29名志愿者,用双能X线吸收法(DEXA)测量腰椎骨密度(BMD),并与用该仪器测得的跟骨SOS,BUA值进行相关性分析,评估该仪器的有效性。结果:①超声参数SOS,BUA的短期CVRMS%分别为0.30,4.24;中期CVRMS%分别为0.41,4.20。②SOS与腰椎BMD的相关系数r=0.486(P<0.01),BUA与腰椎BMD的相关系数r=0.629(P<0.01)。结论:与国际主流定量超声(QUS)检测仪器相比,热固耦合式超声骨强度仪具有较高的可重复性和准确性,可用于临床骨质状况评估。     

Dose effects of propranolol on cancellous and cortical bone in ovariectomized adult rats

Animal studies suggest that bone remodeling is under beta-adrenergic control via the sympathetic nervous system. The purpose of this study was to examine the preventive effect of different doses of nonspecific beta-blockers (propranolol) on trabecular and cortical bone envelopes in ovariectomized rats. Six-month-old female Wistar rats were ovariectomized (OVX, n = 60) or sham-operated (n = 15). Then, OVX rats were subcutaneously injected with 0.1 (n = 15), 5 (n = 15), or 20 (n = 15) mg/kg propranolol or vehicle (n = 15) for 10 weeks. Tibial and femoral bone mineral density (BMD) were analyzed longitudinally by dual-energy X-ray absorptiometry. At death, the left tibial metaphysis and L(4) vertebrae were removed, and microcomputed tomography (Skyscan 1072; Skyscan, Aartselaar, Belgium) was performed for trabecular bone structure investigation. Histomorphometry analysis was performed on the right proximal tibia to assess bone cell activities. After 10 weeks, OVX rats had decreased BMD and trabecular parameters and increased bone turnover, as well as cortical porosity compared with the sham group (p < 0.001). Bone architecture alteration was preserved by 0.1 mg/kg propranolol due to higher trabecular number and thickness (+50.35 and +6.81%, respectively, than OVX; p < 0.001) and lower cortical pore number (-52.38% than OVX; p < 0.001). Animals treated by 0.1 mg/kg propranolol had a lower osteoclast surface and a higher osteoblast activity compared with OVX. Animals treated by 20 mg of propranolol did not significantly differ from OVX rats. Animals treated by 5 mg of propranolol have been partially preserved from the ovariectomy. These results showed a dose effect of beta-blockers. The lower the dose of propranolol breeding, the better the preventive effect against ovariectomy.     

Prediction of mechanical properties of human trabecular bone by electrical measurements

In trabecular bone, the interrelationships of electrical and dielectric properties with mechanical characteristics are poorly known. Information on these relations is crucial for evaluation of the diagnostic potential of impedance techniques. In this study, electrical and dielectric properties, i.e. permittivity, conductivity, phase angle, loss factor, specific impedance and dissipation factor of human trabecular bone samples (n=26, harvested from the distal femur and proximal tibia) were characterized in a wide frequency range (50 Hz-5 MHz). Mechanical properties, i.e. Young's modulus, ultimate strength, yield stress, yield strain and resilience of the samples (n=20) were determined by using destructive compressive testing. Subsequently, measurements of electrical and dielectric properties were repeated after mechanical testing. The measurements were also repeated for the control samples (n=6) that were not mechanically tested. Electrical, dielectric or mechanical properties showed no significant differences between the intact femoral and tibial samples. The electrical and dielectric parameters as well as the linear correlations between the dielectric and electrical parameters with mechanical parameters were strongly frequency dependent. At the frequency of 1.2 MHz, the relative permittivity showed the strongest linear correlations with the Young's modulus (r=0.71, p<0.01, n=20) and ultimate strength (r=0.73, p<0.01, n=20). Permittivity and dissipation factor showed statistically significant changes after mechanical testing. Our results suggest that the measurements of low frequency electrical and dielectric properties may provide information on the mechanical status of trabecular bone and, possibly, may even help to diagnose bone microdamage. In the future, these measurement techniques may be further developed for use during open surgery, such as bone grafting or total hip replacement surgery.     

The role of quantitative ultrasound in the assessment of bone: a review

Quantitative ultrasound (QUS) bone measurement is a promising, relatively new technique for the diagnosis of osteoporosis. Unlike to the more established method of bone densitometry [measurement of bone mineral density (BMD) e.g. using dual X-ray absorptiometry (DEXA)], QUS does not use ionizing radiation. It is cheaper, takes up less space and is easier to use than densitometry techniques. The two QUS parameters currently measured are broadband ultrasound attenuation (BUA) and speed of sound (SOS). The reported age-related changes for healthy women range from ?0·27% to ?1·62% per year for BUA and from ?0·06% to ?0·19% per year for SOS. Precision ranges from 1·0 to 3·8% (CV) for BUA and from 0·19 to 0·30% (CV) for SOS. The new method of imaging ultrasound has improved the precision of QUS measurements. QUS is significantly correlated with BMD. Studies with the latest equipment have shown r-values between 0·6 and 0·9 in site-specific measurements, and QUS is thus believed to reflect mainly BMD. However, other studies indicate that QUS measures something other than the actual mineral content of bone, namely bone quality, e.g. in vitro studies have shown that QUS reflects trabecular orientation independently of BMD. In both cross-sectional and prospective studies, QUS seems to be as good a predictor of osteoporotic fractures as BMD. In two large prospective studies, QUS also predicted fracture risk independently of BMD. QUS has just begun to be used systematically for monitoring the response to anti-osteoporotic treatments in prospective trials. In the studies performed, QUS has been found to be useful in the follow-up of patients. QUS is thus a promising new technique for bone assessment.     

Wavelet-based signal processing of in vitro ultrasonic measurements at the proximal femur

To estimate osteoporotic fracture risk, several techniques for quantitative ultrasound (QUS) measurements at peripheral sites have been developed. As these techniques are limited in the prediction of fracture risk of the central skeleton, such as the hip, we are developing a QUS device for direct measurements at the femur. In doing so, we noticed the necessity to improve the conventional signal processing because it failed in a considerable number of measurements due to multipath transmission. Two sets of excised human femurs (n = 6 + 34) were scanned in transmission mode. Instead of using the conventional methods, the radio-frequency signals were processed with the continuous wavelet transform to detect their time-of-flights for the calculation of speed-of-sound (SOS) in bone. The SOS-values were averaged over a region similar to the total hip region of dual X-ray absorptiometry (DXA) measurements and compared with bone mineral density (BMD) measured with DXA. Testing six standard wavelets, this algorithm failed for only 0% to 6% of scan in test set 1 compared with 29% when using conventional algorithms. For test set 2, it failed for 2% to 12% compared with approximately 40%. SOS and BMD correlated significantly in both test sets (test set 1: r2 = 0.87 to 0.92, p < 0.007; test set 2: r2 = 0.68 to 0.79, p < 0.0001). The correlations are comparable with correlations recently reported. However, the number of evaluable signals could be substantially increased, which improves the perspectives of the in vivo measurements.     

Lipid profile, obesity and bone mineral density: the Hertfordshire Cohort Study

BACKGROUND: Body mass index (BMI) and bone mineral density (BMD) are positively correlated in several studies, but few data relate bone density, lipid profile and anthropometric measures. AIM: To investigate these relationships in a large, well-characterized cohort of men and women (The Hertfordshire Cohort Study). METHODS: Men (n = 465) and women (n = 448) from Hertfordshire, UK were recruited. Information was available on demographic and lifestyle factors, anthropometric measurements, body fat percentage, fasting triglycerides, cholesterol (total, HDL, LDL), apolipoprotein (a) and apolipoprotein (b); bone mineral density (BMD) was recorded at the lumbar spine and total femur. RESULTS: BMD at the lumbar spine (males r = 0.15, p = 0.001; females r = 0.14, p = 0.003) and total femoral region (males r = 0.18, p = 0.0001; females r = 0.16, p = 0.0008) was related to serum triglyceride level, even after adjustment for waist-hip ratio, age, social class and lifestyle factors, but not if body fat percentage was substituted for waist-hip ratio in the regression model. Fasting HDL cholesterol level was related to lumbar spine BMD in women (r = -0.15, p = 0.001) and total femoral BMD in both sexes (males r = -0.15, p = 0.002; females r = -0.23, p < 0.0001); these relationships were also attenuated by adjustment for body fat percentage but not waist-hip ratio. No relationships were seen between total or LDL cholesterol with BMD. DISCUSSION: In this cohort, relationships between lipid profile and BMD were robust to adjustment for one measure of central obesity (waist-hip ratio), but not total body fat. This broadly supports the idea that adiposity may confound the relationship between lipids and bone mass.     

Ultrasound simulation in the distal radius using clinical high-resolution peripheral-CT images

The overall objective of this research is to develop an ultrasonic method for noninvasive assessment of the distal radius. The specific objective of this study was to examine the propagation of ultrasound through the distal radius and determine the relationships between bone mass and architecture and ultrasound parameters. Twenty-six high-resolution peripheral-CT clinical images were obtained from a set of subjects that were part of a larger study on secondary osteoporosis. A single midsection binary slice from each image was selected and used in the two-dimensional (2D) simulation of an ultrasound wave propagating from the anterior to the posterior surfaces of each radius. Mass and architectural parameters associated with each radius, including total (trabecular and cortical) bone mass, trabecular volume fraction, trabecular number and trabecular thickness were computed. Ultrasound parameters, including net time delay (NTD), broadband ultrasound attenuation (BUA) and ultrasound velocity (UV) were also evaluated. Significant correlations were found between NTD and total bone mass (R2 = 0.92, p < 0.001), BUA and trabecular number (R2 = 0.78, p < 0.01) and UV and trabecular bone volume fraction (R2 = 0.82, p < 0.01). There was only weak, statistically insignificant correlation (R2 < 0.14, p = 0.21) found between trabecular thickness and any of the ultrasound parameters. The study shows that ultrasound measurements are correlated with bone mass and architecture at the distal radius and, thus, ultrasound may prove useful as a method for noninvasive assessment of osteoporosis and fracture risk.     

Speed of sound, bone mineral density and bone strength in oophorectomized rats

BACKGROUND: The aim of this study was to determine the sensitivity of bone mineral density (BMD), ultrasounds (SOS) and resistance to torsion (T) to detect experimental osteopenia induced in rats 3 and 6 months after ooforectomy. MATERIALS AND METHODS: Seventy-four rats were used, divided into four groups, ooforectomized rats analysed 3 and 6 months after the operation and their respective control groups, in which BMD (Hologic QDR 1000 S/N 277), SOS (DBM Sonic 1200) and T (adapted test machine) were determined in the right femur. RESULTS: The results of the three techniques distinguished the ooforectomized groups from the controls, both 3 and 6 months after the ooforectomy, obtaining more significant differences with BMD (P = 0.0006, P = 0. 001, respectively) than SOS and T, where a significance of only P = 0.05 was obtained. In the correlation study among the three techniques, a significant correlation was observed between BMD and SOS (r = 0.39, P = 0.0008), as well as between BMD and T (r = 0.31, P = 0.03). However, significance was not observed between the SOS and T tests. CONCLUSION: In the study of sensitivity and specificity of the techniques used to detect the osteopenia caused by the ooforectomy, by means of calculation of the area under the receiver operation characteristic (ROC) curve, it was proven that although the three techniques distinguished between the two analysed populations, BMD presented an area under the ROC curve that was superior (0.87, 0.85) to that obtained with SOS (0.73, 0.67) and T (0.73, 0.68), both 3 and 6 months after the operation.     

Quantitative ultrasound at the phalanxes discriminates osteoporotic women with vertebral but not with hip fracture

Caucasian postmenopausal women with vertebral fracture (38), hip fracture (38) and without fracture (124) were measured by spine and femoral neck bone mineral density (BMD) (Norland XR 36), and two quantitative ultrasound (US) or QUS parameters (Igea DBM sonic 1200): the amplitude-dependent speed of sound (Ad-Sos) and the US bone profile score (UBPS), at the proximal hand phalanxes to investigate the ability of QUS to detect previous fracture. Age, height and weight were not different among groups, but menopausal age was lower with vertebral fracture (p < 0.005). QUS parameters of hip (AdSos = 1806.2 +/- 104.6 m s(-1); UBPS = 0.22 +/- 0.13) or spine fracture (AdSos = 1774.4 +/- 90.0 m s(-1); UBPS = 0.19 +/- 0.10) were not significantly lower than controls (AdSos = 1819.1 +/- 111.9 m s(-1); UBPS = 0.25 +/- 0.17), and BMD of hip (spine: 756.0 +/- 138.9 mg cm(-2); femoral neck: 583.6 +/- 61.8 mg cm(-2)) and vertebral (spine: 727.4 +/- 120.4 mg cm(-2); femoral neck: 592.8 +/- 82.1 mg cm(-2);) fracture was lower than controls (spine: 829.2 +/- 167.6 mg cm(-2); femoral neck 665.0 +/- 108.9 mg cm(-2)) (p < 0.001). Spine and femoral neck BMD significantly separated both types of fractures from controls, but AdSos and UBPS significantly separated only vertebral fractures. Femoral neck BMD has the best receiver operating characteristic (ROC) area for both hip (0.715, SE 0.043) and vertebral (0.693, SE 0.047) fractures, being significantly better (p < 0.01) than that of AdSos (0.503, SE 0.056) and UBPS (0.501, SE 0.057) for hip fractures, but not for vertebral fractures (AdSos 0.604, SE 0.050; UBPS 0.563, SE 0.048). In conclusion, QUS at hand phalanxes predicts vertebral fracture as effectively as BMD, but does not predict hip fracture.