Quantitative ultrasound in the assessment of skeletal status

In Vivo Assessment of Bone Quality Without X-rays

PURPOSE OF REVIEW

This review summarizes recent advances in the assessment of bone quality using non-X-ray techniques.

RECENT FINDINGS

Quantitative ultrasound (QUS) provides multiple measurements of bone characteristics based on the propagation of sound through bone, the attenuation of that sound, and different processing techniques. QUS parameters and model predictions based on backscattered signals can discriminate non-fracture from fracture cases with accuracy comparable to standard bone mineral density (BMD). With advances in magnetic resonance imaging (MRI), bound water and pore water, or a porosity index, can be quantified in several long bones in vivo. Since such imaging-derived measurements correlate with the fracture resistance of bone, they potentially provide new BMD-independent predictors of fracture risk. While numerous measurements of mineral, organic matrix, and bound water by Raman spectroscopy correlate with the strength and toughness of cortical bone, the clinical assessment of person's bone quality using spatially offset Raman spectroscopy (SORS) requires advanced spectral processing techniques that minimize contaminating signals from fat, skin, and blood. Limiting exposure of patients to ionizing radiation, QUS, MRI, and SORS has the potential to improve the assessment of fracture risk and track changes of new therapies that target bone matrix and micro-structure.

Association between global biomarker of oxidative stress and quantitative ultrasound parameters in middle-aged and elderly adults: A cross-sectional study

Introduction

With the population aging, osteoporosis has become a major public health concern. Elevated oxidative stress is a vital detrimental factor for bone health. Compared to common oxidative stress-related biomarkers, Fluorescent Oxidation Products (FlOPs) reflect the global levels of oxidation from proteins, lipids, and DNA. Nevertheless, whether plasma FlOP levels are related to bone health measured by Quantitative ultrasound (QUS) is unclear. Thus, the present study examined the association between FlOPs and QUS parameters in middle-aged and elderly adults.

Methods

This community-based cross-sectional study was conducted in Changchun, northeast China. Plasma FlOPs were determined by a fluorescent microplate reader at a wavelength of 320/420 nm (excitation/emission). QUS parameters [speed of sound (SOS) and broadband ultrasound attenuation (BUA)] of the calcaneus were assessed by an ultrasound bone densitometer. We used multivariable linear regression to examine the association between FlOPs and QUS parameters.

Results

A total of 491 subjects were included in this study. Their average age was 65.2 years (standard deviation [SD]: 9.7 years). FlOPs were inversely associated with SOS (β for an increase of logarithmic interquartile range = -10.64; P = 0.018). Higher FlOP levels were marginally associated with lower SOS in females (β for an increase of logarithmic interquartile range = -9.68, P = 0.066), but not in males (β for an increase of logarithmic interquartile range = -11.84, P = 0.131). No significant relationship between FlOPs and BUA was observed.

Conclusions

Plasma FlOP levels were inversely associated with SOS, but not with BUA in middle-aged and elderly adults.

Short-termed changes in quantitative ultrasound estimated bone density among young men in an 18-weeks follow-up during their basic training for the Swiss Armed Forces

Background

Quantitative Ultrasound (QUS) methods have been widely used to assess estimated bone density. This study aimed to assess changes in estimated bone density in association with changes in body composition, physical activity, and anthropometry.

Methods

We examined changes in anthropometry, body composition, and physical activity associated with changes in estimated bone mineral density (measured using quantitative ultrasound with a heel ultrasound device indicating broadband ultrasound attenuation BUA and speed of sound SOS) in a follow-up sample of n = 73 young men at the beginning and again 18 weeks later at the end of basic military training.

Results

At the end of the basic training, the subjects were on average significantly heavier (+1.0%), slightly taller (+0.5%) and had a higher fat mass (+6.6%) and grip strength (+8.6%). A significant decrease in mean physical activity (-49.5%) and mean estimated bone density calculated with BUA (-7.5%) was observed in the paired t-test. The results of the multivariable linear regressions (backward selection) show that changes in skeletal muscle mass (delta = 2nd measurement minus 1st measurement) have negative and body weight (delta) have positive association with the speed of sound SOS (delta), while fat mass (delta) and physical activity (delta) had the strongest negative associations with estimated bone mineral density (delta). In particular, we found a negative association between fat mass (delta) and estimated bone mineral density (delta, estimated with BUA).

Conclusion

Our study suggests that estimated bone density from the calcaneus can change within a few months even in young and mostly healthy individuals, depending upon physical activity levels and other co-factors. Further studies including other troop types as control groups as well as on women should follow in order to investigate this public health relevant topic in more depth. To what extent the estimated bone density measurement with quantitative ultrasound is clinically relevant needs to be investigated in further studies.

Identifying Calcaneal Anatomical Regions of Interest (ROI) for Quantitative Ultrasound Application in Subadults

Whilst quantitative ultrasound can be reliably used to assess bone health in adults, the fixed location of the transducers in current devices may result in inaccurate and unreliable measurements in bone assessment in children due to the variation in foot size during growth. To improve positioning for paediatric assessment, Jaworski et al. (1995) created an anatomical method to identify the region of interest (ROI), however, there have been no medical imaging studies to confirm that the Jaworski method results in consistent placement of the transducer on the centre of the calcaneal body to avoid edge artefacts. In this study, computed tomography scans of the tarsus were collected from 498 individuals (258 females; 240 males) aged 2 to 20 years and used to create three novel anatomical methods to identify ROI on the calcaneus using palpable landmarks. In addition, the established Jaworski method was applied to the same scans and compared to our novel methods. The maximum ROI significantly increased with age with males having significantly greater diameters, supporting the recommendation that ½ inch diameter transducers should be used on individuals younger than 7 years of age. We identified that 79% of the 'Jaworski points' lied anterosuperior to the ROI centre point identified in this study, with 10% of the points lying outside the ROI. Of the three novel methods, only the calcaneal insertion method demonstrated small measurement variance between individuals of the same age in each sex and is therefore the preferred method for ultrasound clinical application.

Urinary Potential Renal Acid Load (uPRAL) among Vegans Versus Omnivores and Its Association with Bone Health in the Cross-Sectional Risks and Benefits of a Vegan Diet Study

Both veganism and high dietary acid load are linked to unfavorable bone health. However, the specific role of dietary alkali or acid load for the bone health of vegans is so far unknown. Thus, the renal biomarker for dietary acid or alkali load, i.e., urinary potential renal acid load (uPRAL), was measured in 24 h urine samples of 34 vegans and 35 omnivores (50.7% males). Bone health was assessed via calcaneal quantitative ultrasound. Associations between uPRAL and bone health indices were examined using multivariable general linear models. Compared to omnivores, vegans had a significantly lower uPRAL (mean difference = −34.5 mEq/24 h, p < 0.0001), a lower 24 h urinary phosphate excretion (p = 0.0004), a lower 24 h urinary sulfate excretion (p = 0.01), and a higher urine pH value (p < 0.0001). Broadband ultrasound attenuation (BUA) was lower among vegans versus omnivores (p = 0.037), yet it was not associated with uPRAL irrespective of adjustments. This study confirms different acid-base profiles of vegans and omnivores, with a pronounced alkaline excess among vegans and a rather low acid load among a group of omnivores with moderate protein intake. Within this spectrum of alkaline to low acid load, no association with bone health was found.

Bone Quality in CKD Patients: Current Concepts and Future Directions - Part I

BACKGROUND

There is ample evidence that patients with CKD have an increased risk of osteoporotic fractures. Bone fragility is not only influenced by low bone volume and mass but also by poor microarchitecture and tissue quality. More emphasis has been given to the quantitative rather than qualitative assessment of bone health, both in general population and CKD patients. Although bone mineral density (BMD) is a very useful clinical tool in assessing bone strength, it may underestimate the fracture risk in CKD patients. Serum and urinary bone biomarkers have been found to be reflective of bone activities and predictive of fractures independently of BMD in CKD patients. Bone quality and fracture risk in CKD patients can be better assessed by utilizing new technologies such as trabecular bone score and high-resolution imaging studies. Additionally, invasive assessments such as bone histology and micro-indentation are useful counterparts in the evaluation of bone quality.

SUMMARY

A precise diagnosis of the underlying skeletal abnormalities in CKD patients is crucial to prevent further bone loss and fractures. We must consider bone quantity and quality abnormalities for management of CKD patients. Here in this part I, we are focusing on advances in bone quality diagnostics that are expected to help in proper understanding of the bone health in CKD patients.

KEY MESSAGES

Assessment of bone quality and quantity in CKD patients is essential. Both noninvasive and invasive techniques for the assessment of bone quality are available.

Ultrasound reference values for the calcaneus of children and adolescents at moderate altitudes in Peru

OBJECTIVE

a) Establish reference values for bone parameters by using the speed of sound (SOS, m/s) of broadband ultrasound attenuation (BUA, dB/MHz) and establish a bone quality index (BQI=αSOS+βBUA) for children and adolescents living in a region of moderate altitude, b) compare bone parameters with an international standard (with different ethnic, socio-economic, and lifestyle backgrounds) by using ultrasound of the calcaneus (heel bone) (QUS).

METHODS

A descriptive cross-sectional study was carried out with children and adolescents between the ages of 6.0 and 16.9 years old. The sample was selected randomly. A total of 1322 subjects were studied. Weight, height, and bone parameters, using ultrasound of the calcaneus, were evaluated SOS, BUA, and BQI. Body Mass Index BMI was calculated.

RESULTS

The average age of males was 11.44±0.35 years old, and for females, it was 11.43±0.35 years old. The students in this research showed slightly higher values of SOS, BUA, and BQI for both sexes when compared with the international reference (the 50th percentile). Percentiles were generated (P3, P10, P25, P50, P75, P90, and P97) using the LMS method [median (M), standard deviation (S), and power of the Box-Cox transformation (L)] by age and sex.

CONCLUSION

The students living at a moderate altitude showed slightly higher values in bone parameters in relation to the international reference. This pattern depicted a population with a better state of bone health. The proposed percentiles may be used to categorize adequate to at risk bone parameters based on age and sex.

Recent advancements in the analysis of bone microstructure: New dimensions in forensic anthropology

Bone is a mechanically active, three-dimensionally (3D) complex, and dynamic tissue that changes in structure over the human lifespan. Bone tissue exists and remodels in 3D and changes over time, introducing a fourth dimension. The products of the remodelling process, secondary and fragmentary osteons, have been studied substantially using traditional two-dimensional (2D) techniques. As a result, much has been learned regarding the biological information encrypted in the histomorphology of bone, yielding a wealth of information relating to skeletal structure and function. Three-dimensional imaging modalities, however, hold the potential to provide a much more comprehensive understanding of bone microarchitecture. The visualization and analysis of bone using high-resolution 3D imaging will improve current understandings of bone biology and have numerous applications in both biological anthropology and biomedicine. Through recent technological advancements, we can hone current anthropological applications of the analysis of bone microstructure and accelerate research into the third and fourth dimensional realms. This review will explore the methodological approaches used historically by anthropologists to assess cortical bone microstructure, spanning from histology to current ex vivo imaging modalities, discuss the growing capabilities of in vivo imaging, and conclude with an introduction of novel non-histological modalities for investigating bone quality.

Osteoporosis: what the clinician needs to know?

Osteoporosis is a common condition and an important cause of disability. For this reason, early detection of the disease and patients at higher risk of bone fractures is compulsory. In the recent years, conventional quantitative methods have been spreading for the diagnosis of osteoporosis; moreover, new improvements in computed tomography (CT) and magnetic resonance imaging (MRI) have been made in this field and imaging findings may correlate to the morphological and structural changes within the bone.

Clinical guidelines for the prevention and treatment of osteoporosis: summary statements and recommendations from the Italian Society for Orthopaedics and Traumatology

BACKGROUND

The Italian Society for Orthopaedics and Traumatology conceived this guidance-which is primarily addressed to Italian orthopedic surgeons, but should also prove useful to other bone specialists and to general practitioners-in order to improve the diagnosis, prevention, and treatment of osteoporosis and its consequences.

MATERIALS AND METHODS

Literature reviews by a multidisciplinary team.

RESULTS

The following topics are covered: the role of instrumental, metabolic, and genetic evaluations in the diagnosis of osteoporosis; appraisal of the risk of fracture and thresholds for intervention; general strategies for the prevention and treatment of osteoporosis (primary and secondary prevention); the pharmacologic treatment of osteoporosis; the setting and implementation of fracture liaison services for tertiary prevention. Grade A, B, and C recommendations are provided based on the main levels of evidence (1-3). Toolboxes for everyday clinical practice are provided.

CONCLUSIONS

The first up-to-date Italian guidelines for the primary, secondary, and tertiary prevention of osteoporosis and osteoporotic fractures are presented.

Advances in imaging approaches to fracture risk evaluation

Fragility fractures are a growing problem worldwide, and current methods for diagnosing osteoporosis do not always identify individuals who require treatment to prevent a fracture and may misidentify those not a risk. Traditionally, fracture risk is assessed using dual-energy X-ray absorptiometry, which provides measurements of areal bone mineral density at sites prone to fracture. Recent advances in imaging show promise in adding new information that could improve the prediction of fracture risk in the clinic. As reviewed herein, advances in quantitative computed tomography (QCT) predict hip and vertebral body strength; high-resolution HR-peripheral QCT (HR-pQCT) and micromagnetic resonance imaging assess the microarchitecture of trabecular bone; quantitative ultrasound measures the modulus or tissue stiffness of cortical bone; and quantitative ultrashort echo-time MRI methods quantify the concentrations of bound water and pore water in cortical bone, which reflect a variety of mechanical properties of bone. Each of these technologies provides unique characteristics of bone and may improve fracture risk diagnoses and reduce prevalence of fractures by helping to guide treatment decisions.

Osteoprotegerin and uremic osteoporosis in chronic hemodialysis patients

INTRODUCTION

Osteoprotegerin (OPG) is a powerful inhibitor of osteoclast activity, and it plays an important role in bone metabolism. In hemodialysis (HD) patients, the relationship between OPG and bone mineral density (BMD) is important, but remains unclear yet. The study objective was to assess the OPG role related to uremic osteoporosis in HD patients.

METHODS

This cross-sectional study has been realized on a cohort of 63 chronic HD patients.

INCLUSION CRITERIA

elderly prevalent HD patients with an age over 55 years old.

EXCLUSION CRITERIA

previous bone disease or previous renal transplant; neoplasia; parathyroidectomy, hormone replacement therapy. The data regarding demographical and clinical characteristics, including treatments for mineral and cardiovascular complications, were recorded. Serum OPG and mineral markers levels were measured. BMD was assessed by calcaneus quantitative ultrasound; it measured broadband ultrasound attenuation, speed of sound (SOS) and stiffness index (STI).

RESULTS

The high OPG levels were associated with higher bone mineral density (OPG-SOS P = 0.003; R = 0.37; OPG-STI P = 0.03; R = 0.28). Malnutrition, anemia and advanced age correlated with bone demineralization. Males had higher bone density parameters than females. In patients treated with vitamin D (P = 0.005), the BMD was increased comparing to patients without these treatments.

CONCLUSIONS

OPG levels had directly correlated with bone mineral density parameters. Our study further confirms the critical role of OPG in the pathogenesis of uremic osteoporosis in ESRD. Whether the increased circulant OPG protect against bone loss in patients undergoing HD remains to be established.

Postnatal Changes in Tibial Bone Speed of Sound of Preterm and Term Infants during Infancy

This study aimed to evaluate changes in tibial bone speed of sound (SOS) over time, in preterm and term infants during infancy, in addition to identifying factors influencing the development of tibial SOS during infancy. Preterm (n = 155) and term (n = 65) infants were enrolled in this study. Tibial bone SOS was measured using quantitative ultrasonography (QUS) on the left tibia of newborn infants after birth (within 7 days), at 1 month old, and then every 2 months until subjects were approximately 12-15 months old. Follow-up checks included anthropometric measurements and tibial bone SOS. Mean tibial bone SOS at birth was significantly higher in term infants (mean ± SD, 2968.5 ± 99.7 m/s) than in preterm infants (2912.2 ± 122.6 m/s). Values of follow-up tibial bone SOS declined for the first 4 months, and then increased gradually until 12-15 months old. This increasing trend was greater in preterm infants after 2 months of corrected age than in term infants. There were no significant differences by 12-15 months of age between preterm and term infants. A longitudinal mixed-effect model controlling for internal correlations and other covariates in the two groups showed that age and the SOS value at birth were important factors affecting the tibial bone SOS in both preterm and term newborn infants during infancy. There are significant differences in the pattern of change in tibial bone SOS values between preterm and term infants during the first 12-15 months of life. Age and SOS value at birth were important factors affecting the pattern of tibial bone SOS change in both preterm and term newborn infants during infancy.

Is calcaneal broadband ultrasound attenuation a valid index of dual-energy x-ray absorptiometry-derived bone mass in children?

Objectives

The aim of the current study was to assess whether calcaneal broadband ultrasound attenuation (BUA) can predict whole body and regional dual-energy x-ray absorptiometry (DXA)-derived bone mass in healthy, Australian children and adolescents at different stages of maturity.

Methods

A total of 389 boys and girls across a wide age range (four to 18 years) volunteered to participate. The estimated age of peak height velocity (APHV) was used to classify children into pre-, peri-, and post-APHV groups. BUA was measured at the non-dominant heel with quantitative ultrasonometry (QUS) (Lunar Achilles Insight, GE), while bone mineral density (BMD) and bone mineral content (BMC) were examined at the femoral neck, lumbar spine and whole body (DXA, XR-800, Norland). Associations between BUA and DXA-derived measures were examined with Pearson correlations and linear regression. Participants were additionally ranked in quartiles for QUS and DXA measures in order to determine agreement in rankings.

Results

For the whole sample, BUA predicted 29% of the study population variance in whole body BMC and BMD, 23% to 24% of the study population variance in lumbar spine BMC and BMD, and 21% to 24% of the variance in femoral neck BMC and BMD (p < 0.001). BUA predictions were strongest for the most mature participants (pre-APHV R² = 0.03 to 0.19; peri-APHV R² = 0.05 to 0.17; post-APHV R² = 0.18 to 0.28) and marginally stronger for girls (R² = 0.25-0.32, p < 0.001) than for boys (R² = 0.21-0.27, p < 0.001). Agreement in quartile rankings between QUS and DXA measures of bone mass was generally poor (27.3% to 38.2%).

Conclusion

Calcaneal BUA has a weak to moderate relationship with DXA measurements of bone mass in children, and has a tendency to misclassify children on the basis of quartile rankings.

Cite this article: B. K. Weeks, R. Hirsch, R. C. Nogueira, B. R. Beck. Is calcaneal broadband ultrasound attenuation a valid index of dual-energy x-ray absorptiometry-derived bone mass in children? Bone Joint Res 2016;5:538–543. DOI: 10.1302/2046-3758.511.BJR-2016-0116.R1.

Vitamin D and Calcium Intakes, Physical Activity, and Calcaneus BMC among School-Going 13-Year Old Malaysian Adolescents

Background: Dietary calcium and vitamin D are essential for bone development. Apart from diet, physical activity may potentially improve and sustain bone health. Objective: To investigate the relationship between the dietary intake of calcium and vitamin D, physical activity, and bone mineral content (BMC) in 13-year-old Malaysian adolescents. Design: Cross-sectional. Setting: Selected public secondary schools from the central and northern regions of Peninsular Malaysia. Participants: The subjects were from the Malaysian Health and Adolescents Longitudinal Research Team Cohort study (MyHeARTs). Methods: The data included seven-day diet histories, anthropometric measurements, and the BMC of calcaneal bone using a portable broadband ultrasound bone densitometer. Nutritionist Pro software was used to calculate the dietary calcium and vitamin D intakes from the diet histories, based on the Nutrient Composition of Malaysian Food Database guidance for the dietary calcium intake and the Singapore Energy and Nutrient Composition of Food Database for vitamin D intake. Results: A total of 289 adolescents (65.7% females) were recruited. The average dietary intakes of calcium and vitamin D were 377 ± 12 mg/day and 2.51 ± 0.12 µg/day, respectively, with the majority of subjects failing to meet the Recommended Nutrient Intake (RNI) of Malaysia for dietary calcium and vitamin D. All the subjects had a normal Z-score for the BMC (−2.00 or higher) with a mean of 0.55 ± 0.01. From the statistical analysis of the factors contributing to BMC, it was found that for those subjects with a higher intake of vitamin D, a higher combination of the intake of vitamin D and calcium resulted in significantly higher BMC quartiles. The regression analysis showed that the BMC might have been influenced by the vitamin D intake. Conclusions: A combination of the intake of vitamin D and calcium is positively associated with the BMC.

Serum uric acid is associated with quantitative ultrasound parameters in men: data from the Camargo cohort

This study analyzes the association between serum uric acid levels and heel quantitative ultrasound (QUS) parameters in men aged 50 or more from the Camargo cohort. We found that higher serum uric acid levels are positively associated with all QUS measurements, suggesting a better bone quality in men with elevated serum uric acid values.

INTRODUCTION

Higher serum uric acid concentrations have been associated with higher bone mineral density and lower prevalence of fractures. However, there are no studies that have assessed the bone quality properties in Caucasians. Therefore, we have analyzed the association between quantitative ultrasound (QUS) and serum uric acid levels in adult men from a population-based cohort.

METHODS

A total of 868 men older than 50 were recruited from a larger cohort (Camargo Cohort) after excluding those with any known condition or drug treatment with a possible influence on bone metabolism, or those with a previous diagnosis of gout or taking hipouricemic agents. Bone turnover markers (PINP and CTX), 25OH-vitamin D and PTH levels were measured by electrochemiluminiscence. BMD was determined by DXA, and heel QUS with a gel-coupled device.

RESULTS

Lumbar, femoral neck and total hip BMD was significantly higher in men with higher serum uric acid levels. QUS parameters were also significantly higher in men with high uric acid levels than those with lower values, and increased continuously across quartiles after adjustment for confounding variables. In multiple regression analysis, serum uric acid was significantly associated with all QUS parameters. Finally, men with serum acid levels above median showed higher values in all the QUS parameters than men with lower values.

CONCLUSIONS

Higher serum uric acid levels in men older than 50 years are positively associated with QUS parameters. These data might suggest a better bone quality in men with elevated serum uric acid values.

In Vivo Quantitative MR Imaging of Bound and Pore Water in Cortical Bone

PURPOSE

To translate and evaluate an in vivo magnetic resonance (MR) imaging protocol for quantitative mapping of collagen-bound and pore water concentrations in cortical bone that involves relaxation-selective ultrashort echo time (UTE) methods.

MATERIALS AND METHODS

All HIPAA-compliant studies were performed with institutional review board approval and written informed consent. UTE imaging sequences were implemented on a clinical 3.0-T MR imaging unit and were used for in vivo imaging of bound and pore water in cortical bone. Images of the lower leg and wrist were acquired in five volunteers each (lower leg: two men and three women aged 24, 24, 49, 30, and 26 years; wrist: two men and three women aged 31, 23, 25, 24, and 26 years) to generate bound and pore water concentration maps of the tibia and radius. Each volunteer was imaged three times, and the standard error of the measurements at the region-of-interest (ROI) level was computed as the standard deviation across studies, pooled across volunteers and ROIs.

RESULTS

Quantitative bound and pore water maps in the tibia and radius, acquired in 8-14 minutes, had per-voxel signal-to-noise ratios of 18 (bound water) and 14 (pore water) and inter-study standard errors of approximately 2 mol (1)H per liter of bone at the ROI level.

CONCLUSION

The results of this study demonstrate the feasibility of quantitatively mapping bound and pore water in vivo in human cortical bone with practical human MR imaging constraints.

Measurement properties of radial and tibial speed of sound for screening bone fragility in 10- to 12-year-old boys and girls

The objective of this study was to analyze measurement properties of the radial and tibial speed of sound (SoS) evaluated by quantitative ultrasound (QUS) for screening bone fragility. Bone fragility was defined as low whole body less head bone mineral density (WBLH BMD) measured by DXA (first tertile, 95% CI -1.1 to -0.9) and as past fractures evaluated by questionnaire. The sample included 319 nonobese boys and girls, ages 10-12 yr. All bone variables were standardized. The results revealed concordance coefficient correlations between WBLH BMD and radial and tibial SoS of 0.129 and 0.038, respectively. The regression lines between DXA and QUS variables were different from the identity lines. Cross-classification analysis by Kappa statistic showed that only 34% and 36% of the 113 participants categorized in the first tertile of WBLH BMD were also categorized in the first tertile of tibial and radial SoS, correspondingly. Logistic regression with gender and maturity adjustments demonstrates that radial SoS was the single significant variable in predicting OR for identifying participants with past fractures. In conclusion, the radial QUS revealed itself to be a valuable tool for screening bone fragility in youth of 10-12 yr, despite the absence of agreement with DXA WBLH BMD.

Novel assessment tools for osteoporosis diagnosis and treatment

This review describes new technologies for the diagnosis and treatment, including fracture risk prediction, of postmenopausal osteoporosis. Four promising technologies and their potential for clinical translation and basic science studies are discussed. These include reference point indentation (RPI), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and magnetic resonance imaging (MRI). While each modality exploits different physical principles, the commonality is that none of them require use of ionizing radiation. To provide context for the new developments, brief summaries are provided for the current state of biomarker assays, fracture risk assessment (FRAX), and other fracture risk prediction algorithms and quantitative ultrasound (QUS) measurements.

Quantitative ultrasound applied to metacarpal bone in infants

Aim. To provide bone status assessment in infancy using quantitative ultrasound (QUS) applied to second metacarpus.

Methods. 103 healthy term infants and 3 patients with rickets, aged ≤ 12 months, underwent metacarpal QUS evaluation using QUS DBM Sonic Aurora IGEA (MO, Italy), which measures speed of sound (mcSOS) and bone transmission time (mcBTT).

Results. In the total sample, median (interquartile range) of mcSOS was 1640.00 (26.0) m/s and mcBTT 0.82 (0.21) µs. Moreover, reference values for age were obtained based on estimation of the lower and upper percentiles. We observed a statistical significant difference between groups of age for mcSOS (p = 0.016). In a multiple linear regression model, we found a relation between age at enrolment and mcSOS (β = −0.608; p = 0.000) and mcBTT (β = −0.819; p = 0.001). A positive correlation between mcSOS and mcBTT has been observed (r = 0.631; p = 0.000). All the patients with rickets showed values of mcSOS and mcBTT lower than the 10th percentile.

Conclusion. Our findings show that this new simple technique appears to be a promising tool for monitoring bone mineral status in pediatric clinical practice and in early life. Furthermore, it could be considered a useful method to investigate and to monitor the role of different factors on programming of bone health and it should be tested as a new method for monitoring subjects with rickets during therapy.

Target detection in diagnostic ultrasound: Evaluation of a method based on the CLEAN algorithm

A technique is proposed for the detection of abnormalities (targets) in ultrasound images using little or no a priori information and requiring little operator intervention. The scheme is a combination of the CLEAN algorithm, originally proposed for radio astronomy, and constant false alarm rate (CFAR) processing, as developed for use in radar systems. The CLEAN algorithm identifies areas in the ultrasound image that stand out above a threshold in relation to the background; CFAR techniques allow for an adaptive, semi-automated, selection of the threshold. Neither appears to have been previously used for target detection in ultrasound images and never together in any context. As a first step towards assessing the potential of this method we used a widely used method of simulating B-mode images (Field II). We assumed the use of a 256 element linear array operating at 3.0MHz into a water-like medium containing a density of point scatterers sufficient to simulate a background of fully developed speckle. Spherical targets with diameters ranging from 0.25 to 6.0mm and contrasts ranging from 0 to 12dB relative to the background were used as test objects. Using a contrast-detail analysis, the probability of detection curves indicate these targets can be consistently detected within a speckle background. Our results indicate that the method has considerable promise for the semi-automated detection of abnormalities with diameters greater than a few millimeters, depending on the contrast.

Bone status and associated factors measured by quantitative ultrasound in preterm and full-term newborn infants

BACKGROUND

A clear understanding of the factors associated with bone status in newborn infants is essential for devising strategies for preventing osteoporotic fracture in future generations.

OBJECTIVE

The aims of this study were to perform bone speed of sound (SOS) to assess the status of the tibia in preterm and full-term newborns, and to evaluate factors associated with bone status at birth.

STUDY DESIGNS

Bone SOS was measured by quantitative ultrasonography on the left tibia in full-term and preterm newborn infants immediately after birth. A birth chart and maternal history were recorded. Univariate and multivariate analyses were performed to identify factors affecting bone SOS at birth.

SUBJECTS

The study analyzed 667 infants, including 370 males and 297 females, during study period.

RESULTS

Univariate analysis revealed that gender, gestational age (GA) and birth anthropometrics significantly affected tibial bone SOS at birth whereas maternal factors did not. Multivariate multiple regression analysis revealed that gender (male-to-female coefficient of 45.71 and 32.52 in premature and full-term infants, respectively), GA (coefficient of 32.55 and 31.27 in premature and full-term infants, respectively, for every 1-week increase), and birth weight (coefficient of -0.11 and -0.103 in premature and full-term infants, respectively, for every 1-gram increase) were important factors affecting tibial bone SOS in both preterm and full-term newborn infants at birth.

CONCLUSIONS

Male gender and advanced GA have a positive effect on increasing tibial bone SOS at birth, while birth weight had a negative effect on increasing tibial bone SOS. Tibial bone SOS is higher in small-for-gestational-age infants than in those of appropriate-for-gestational-age infants.

Phalangeal quantitative ultrasound measurements in chronic hemodialysis patients: a 4-year follow-up

In the course of chronic kidney disease, bone metabolism disturbances occur and become aggravated simultaneously with the progression of renal disorder, worsening patients' quality of life. We conducted a 4-year follow-up to assess phalangeal quantitative ultrasound (QUS) measurements in 32 patients undergoing chronic hemodialysis (17 males and 15 females) whose mean ages were 56.3 ± 15.2 years. The QUSs of hand phalanges were performed using DBM 1200 (IGEA, Carpi, Italy) and are expressed as amplitude-dependent speed of sound (Ad-SoS), Z-scores, and T-scores. In comparison with the age-, sex-, and body mass index-adjusted control group, QUS parameters were significantly decreased in all patients undergoing dialysis. During the 4-year follow-up, Ad-SoS and T-scores in all study groups sloped significantly with time. The significant negative relationships between follow-up Ad-SoS results and both baseline and follow-up parathormone values were demonstrated. Our results confirm a high prevalence of bone disturbances in patients undergoing chronic hemodialysis, and they do not improve during renal replacement therapy. The parathormone level seems to be an important agent in influencing bone status, but further studies are needed to understand the other risk factors in kidney-related bone disease.

Osteoporosis imaging: state of the art and advanced imaging

Osteoporosis is becoming an increasingly important public health issue, and effective treatments to prevent fragility fractures are available. Osteoporosis imaging is of critical importance in identifying individuals at risk for fractures who would require pharmacotherapy to reduce fracture risk and also in monitoring response to treatment. Dual x-ray absorptiometry is currently the state-of-the-art technique to measure bone mineral density and to diagnose osteoporosis according to the World Health Organization guidelines. Motivated by a 2000 National Institutes of Health consensus conference, substantial research efforts have focused on assessing bone quality by using advanced imaging techniques. Among these techniques aimed at better characterizing fracture risk and treatment effects, high-resolution peripheral quantitative computed tomography (CT) currently plays a central role, and a large number of recent studies have used this technique to study trabecular and cortical bone architecture. Other techniques to analyze bone quality include multidetector CT, magnetic resonance imaging, and quantitative ultrasonography. In addition to quantitative imaging techniques measuring bone density and quality, imaging needs to be used to diagnose prevalent osteoporotic fractures, such as spine fractures on chest radiographs and sagittal multidetector CT reconstructions. Radiologists need to be sensitized to the fact that the presence of fragility fractures will alter patient care, and these fractures need to be described in the report. This review article covers state-of-the-art imaging techniques to measure bone mineral density, describes novel techniques to study bone quality, and focuses on how standard imaging techniques should be used to diagnose prevalent osteoporotic fractures.

Osteoporosis imaging: state of the art and advanced imaging

Osteoporosis is becoming an increasingly important public health issue, and effective treatments to prevent fragility fractures are available. Osteoporosis imaging is of critical importance in identifying individuals at risk for fractures who would require pharmacotherapy to reduce fracture risk and also in monitoring response to treatment. Dual x-ray absorptiometry is currently the state-of-the-art technique to measure bone mineral density and to diagnose osteoporosis according to the World Health Organization guidelines. Motivated by a 2000 National Institutes of Health consensus conference, substantial research efforts have focused on assessing bone quality by using advanced imaging techniques. Among these techniques aimed at better characterizing fracture risk and treatment effects, high-resolution peripheral quantitative computed tomography (CT) currently plays a central role, and a large number of recent studies have used this technique to study trabecular and cortical bone architecture. Other techniques to analyze bone quality include multidetector CT, magnetic resonance imaging, and quantitative ultrasonography. In addition to quantitative imaging techniques measuring bone density and quality, imaging needs to be used to diagnose prevalent osteoporotic fractures, such as spine fractures on chest radiographs and sagittal multidetector CT reconstructions. Radiologists need to be sensitized to the fact that the presence of fragility fractures will alter patient care, and these fractures need to be described in the report. This review article covers state-of-the-art imaging techniques to measure bone mineral density, describes novel techniques to study bone quality, and focuses on how standard imaging techniques should be used to diagnose prevalent osteoporotic fractures.

Integrated imaging approach to osteoporosis: state-of-the-art review and update

Osteoporosis is the most common of all metabolic bone disorders. It is characterized by low bone mass and microarchitectural deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fractures. Because of the increasing aging of the world population, the number of persons affected by osteoporosis is also increasing. Complications related to osteoporosis can create social and economic burdens. For these reasons, the early diagnosis of osteoporosis is crucial. Conventional radiography allows qualitative and semiquantitative evaluation of osteoporosis, whereas other imaging techniques allow quantification of bone loss (eg, dual-energy x-ray absorptiometry and quantitative computed tomography [CT]), assessment for the presence of fractures (morphometry), and the study of bone properties (ultrasonography). In recent years, new imaging modalities such as micro-CT and high-resolution magnetic resonance imaging have been developed in an attempt to help diagnose osteoporosis in its early stages, thereby reducing social and economic costs and preventing patient suffering. The correct diagnosis of osteoporosis results in better management in terms of prevention and adequate pharmacologic or surgical treatment.

Impact of age, anthropometric data and body composition on calcaneal bone characteristics, as measured by quantitative ultrasound (QUS) in an older German population

The impact of fat-free mass (FFM), fat mass (FM), body mass index (BMI), body mass and body height on calcaneal bone characteristics as measured with quantitative ultrasound (QUS) was investigated in 137 women and 85 men aged 62-92 years, considering age, smoking, waist-to-hip ratio (WHR) and physical activity level (PAL). In regression analyses using various models, in women, age was a negative predictor of speed of sound (SOS), broadband ultrasound attenuation (BUA) and stiffness index (SI) and smoking was a negative predictor of SOS; positive predictors of SOS, BUA, and SI were BMI, body mass and FFM. In men, smoking was a negative predictor and BMI, body mass and FFM were positive predictors of BUA and SI. In both sexes, PAL, body height, WHR and FM had no effect on QUS parameters. The influence of BMI on calcaneal bone characteristics in elderly people depends on FFM rather than on FM.

Bone Status in Activity-Restricted Pregnant Women Assessed Using Calcaneal Quantitative Ultrasound

Objective:

Pregnancy-induced bone loss may be further exacerbated by activity restriction (AR). The authors compared the bone status of AR hospitalized (≥7 days) pregnant women in the third trimester to ambulatory (AM) women at the same gestational age, using a prospective cross-sectional design.

Method:

AR was quantified in AR women by daily step counts using a pedometer for 7 consecutive days. Bone status was evaluated in the left and right calcaneus bones of both AR ( n = 13) and AM ( n = 20) women using quantitative ultrasound (QUS).

Results:

AR women took an average of 1,504 ± 1,377 steps/day. Speed of sound scores (1,543.05 ± 41.97 m/s vs. 1,569.60 ± 46.12 m/s) and broadband ultrasound attenuation (BUA) scores (107.93 ± 9.59 dB/MHz vs. 114.69 ± 17.06 dB/MHz) were not different between the AR and AM groups, respectively ( p > .05). However, bone stiffness index (SI) scores (84.0 ± 16.2 vs. 95.8 ± 22.1, respectively, p < .05) were different between groups, indicating a greater relative risk of future fracture in the AR women.

Conclusion:

Increased fracture risk appears to be a negative side effect incurred through an average of 16 days of hospitalized AR in late pregnancy. Further investigations using a larger sample size are necessary to evaluate the effect of antepartum AR on bone status in the postpartum period to determine if bone status is further attenuated by breastfeeding or if recovery occurs with resumption of ambulation and return of menses and to assess future risk in these women as they age. Prenatal care providers should be made aware of these risks.

Reference data for bone speed of sound in Portuguese girls and boys aged 9-13 years

The objective of this study was to provide reference data for quantitative ultrasound (QUS, Sunlight Omnisense; BeamMed Ltd., Petach-Tikva, Israel) of the radius and tibia in Portuguese subjects. The evaluation was conducted with QUS in 430 healthy participants (213 girls and 217 boys) aged between 9 and 13yr. The results indicate that 13-yr-old girls had higher radial and tibial speed of sound (SOS) than younger girls and higher tibial SOS than boys of the same age (p<0.05). Regression analysis revealed positive associations between radial and tibial SOS and skeletal maturity in girls and negative association between tibial SOS and fat mass in both sexes and average intensity of physical activity in girls (p<0.01). The young Portuguese subjects showed an age-related variation in SOS similar to that seen in some of the eastern Mediterranean countries. Children with a history of fracture of lower (n=24) or upper limbs (n=43) did not show a significant decrease of SOS values in any of the bone sites evaluated (tibia Z-score: -0.23 standard deviations [SDs]; radius Z-score: -0.21 SDs; p>0.05).

Longitudinal changes in calcaneal quantitative ultrasound measures during childhood

This longitudinal study examined how calcaneal quantitative ultrasound (QUS) measures change during childhood while taking into account skeletal maturation, body mass index (BMI), and physical activity. The study reported sex differences in QUS growth curves and an inverse relationship between BMI and speed of sound (SOS) measures.

INTRODUCTION

The aim of this study was to examine how calcaneal QUS parameters change over time during childhood and to determine what factors influence these changes.

METHODS

The study sample consisted of a total of 192 Caucasian children participating in the Fels Longitudinal Study. A total of 548 calcaneal broadband ultrasound attenuation (BUA) and SOS observations were obtained between the ages of 7.6 and 18 years. The best fitting growth curves were determined using statistical methods for linear mixed effect models.

RESULTS

There are significant sex differences in the pattern of change in QUS parameters (p < 0.05). The relationship between QUS measures and skeletal age is best described by a cubic growth curve in boys and a linear pattern among girls. Boys experience their most rapid growth in BUA and SOS in early and late adolescence, while girls experience constant growth throughout childhood. Adiposity levels were significantly associated with the changes in SOS among boys (p < 0.001) and girls (p < 0.01), indicating that children with higher BMI are likely to have lower SOS over time compared to children with lower BMI. For girls, physical activity levels showed positive associations with changes in QUS measures (p < 0.05).

CONCLUSION

This study documents significant sex differences in the pattern of change in QUS measures over childhood and adolescence. Our study also shows significant influences of adiposity and physical activity on the pattern of change in QUS measures during childhood.

Comparative study of quantitative ultrasonography and dual-energy X-ray absorptiometry for evaluating renal osteodystrophy in children with chronic kidney disease

Our aim was to assess bone parameters in children with chronic kidney disease (CKD) with both dual-energy X-ray absorptiometry (DXA) and quantitative ultrasonography (QUS) and additionally with biochemical markers of bone turnover. Twenty children (12 boys and 8 girls) with CKD and a mean decimal age of 9.47 ± 4.44 years were included in the study where anthropometric parameters (height and weight), pubertal status, bone mineral density (BMD) at lumbar spine, speed of sound (SOS) measured by QUS at radius and at tibia, and biochemical markers of bone metabolism were measured. Six patients (30%) had tibial SOS Z score <-1, and 52.7% had radial SOS Z score <-1, whereas only 16.67% had BMD Z score <-1. Patients had significantly increased levels of serum intact parathormone (p < 0.001), serum bone alkaline phosphatase (BAP) (p < 0.001) and serum N-terminal-mid fragment (aminoacids 1-43) of osteocalcin (p < 0.001) compared to controls, whereas serum osteoprotegerin was significantly decreased in patients compared to controls (p = 0.001). SOS was significantly correlated to BAP (r = -0.586, p = 0.013 and r = -0.709, p = 0.001, respectively, for radius and tibia). In conclusion no association between DXA and QUS measurements was documented in our study, whereas QUS was better correlated to biochemical indices of ROD.

Assisted exercise improves bone strength in very low birthweight infants by bone quantitative ultrasound

AIM

To evaluate whether assisted exercise could prevent the development of osteopenia of prematurity, we performed assisted exercise in the study group of very low birthweight (VLBW) premature infants.

METHODS

Sixteen premature infants with birthweight below 1500 g were enrolled in this study and randomly assigned into the exercise (n = 8) and control (n = 8) groups. Assisted exercise involved full extension and flexion range of motion of the upper and lower extremities by a trained nurse with a schedule of 5 days a week for a total of 4 weeks. Bone strength was determined by quantitative ultrasound measurement of tibial bone speed of sound every 2 weeks during the study period.

RESULTS

No difference in gender, birthweight, and gestation age between the exercise and control groups was noted. There was statistically significant less tibial bone speed of sound decrease in the exercise group on the sixth and eighth week of life. During the study period, there were no statistically significant differences in blood biochemistry data, including calcium, phosphorus, magnesium, alkaline phosphatase, osteocalcin and osteoprotegerin, between the two groups.

CONCLUSIONS

This study revealed that early assisted exercise could improve bone strength in very low birthweight infants. The biochemical markers of bone metabolism, osteocalcin and osteoprotegerin, could not be the indicators for early diagnosis of osteopenia of prematurity.

Comparative study of dual energy X-ray absorptiometry and quantitative ultrasonography with the use of biochemical markers of bone turnover in boys with haemophilia

Our aim was to evaluate bone status in boys with haemophilia using dual energy X-ray absorptiometry (DXA) and quantitative ultraSonography (QUS), and in addition, to compare these two methods with the use of biochemical markers of bone turnover. Twenty-six boys with a mean decimal age of 12.08 ± 4.44 years were included in the study which included a DXA scan at lumbar spine and radial, as well as tibial QUS. Serum levels of soluble receptor activator of nuclear factor κB ligand (sRANK-L), osteoprotegerin (OPG) and osteocalcin (OC) were measured and joint evaluation was performed using the Hemophilia Joint Health Score (HJHS). With regard to the study results, only 2 of 26 patients (7.7%) had bone mineral density (BMD) Z-scores < -2, and 4 patients (15.4%) had BMD Z-scores between -1 and -2. Only one patient had radial and other two had tibial QUS Z-scores < -2. No agreement was recorded between QUS and DXA in identifying patients at risk for osteoporosis (k = 0.275, P = 0.063). Haemophiliacs had significantly higher serum levels of sRANK-L (21.04 ± 4.78 vs. 18.58 ± 2.28 ng mL(-1), P = 0.038) and of OC (5.35 ± 2.29 vs. 3.09 ± 0.61 ng mL(-1), P = 0.002) and significantly decreased levels of OPG (15.78 ± 2.53 vs. 23.79 ± 4.39 pg mL(-1), P < 0.001) compared with controls. QUS Z-scores at tibia significantly correlated with HJH Scores (r = -0.450, P = 0.040), whereas lumbar BMD Z-scores significantly correlated with body mass index Z-scores (r = 0.500, P = 0.009). More studies are warranted to identify the most accurate densitometric method for assessing bone status in haemophiliacs.

Radiology of osteoporosis

Bone densitometric studies have shown that osteoporosis is a result of prolonged, slow bone loss and that the pattern of loss is different for trabecular and cortical bone. Structurally-insufficient osteoporotic bone is predisposed to fractures. Among the clinically manifest osteoporotic fractures, distal radius leads the list, followed by hip, spine, and proximal humerus. This article examines the use of conventional radiography as well as other imaging-based modalities for the evaluation of osteoporosis and associated fractures in the axial and appendicular skeleton.

Numerical analysis of uncertainties in dual frequency bone ultrasound technique

Quantitative ultrasound (QUS) measurements are used in the diagnostics of osteoporosis. However, the variation in the thickness and composition of the overlying soft tissue causes significant errors to the bone QUS parameters and diminishes the reliability of the technique in vivo. Recently, the dual frequency ultrasound (DFUS) technique was introduced to minimize the errors related to soft tissue effects. In this study, the significance of soft tissue induced errors and their elimination with the DFUS technique were simulated using the finite difference time domain technique. Furthermore, we investigated the potential of the DFUS corrected integrated reflection coefficient (IRC) of bone to detect changes in the cortical bone density. The effects of alterations in the thickness of fat and lean tissue layers and the inclination between the soft-tissues and between the soft tissue-bone layers were simulated. When the angle of the soft tissue interface was zero, i.e., perpendicular to the incident ultrasound beam, the DFUS-calculated soft tissue composition correlated highly linearly with the true soft tissue composition. The inclination between the soft tissue-bone layers was found to be critical. Even a 2-degree inclination between the soft tissue and the bone surface induced an almost 18% relative error in the corrected IRC. Increasing the inclination between the soft tissue layers increased the error in the DFUS-calculated lean and fat tissue thickness. This error was especially significant at inclination angles greater than 20 degrees. The significant soft tissue induced errors in IRC values (>300 %) could be effectively minimized (<10%) by means of the DFUS correction. Importantly, after the DFUS correction, physiologically relevant variation in the cortical bone density could be detected (p<0.05).