Assessing bone status beyond BMD: evaluation of bone geometry and porosity by quantitative ultrasound of human finger phalanges

Human manual distal phalanges from the Middle Stone Age deposits of Klasies River Main Site, Western Cape Province, South Africa

Two new distal manual phalanges from the Middle Stone Age deposits of Klasies River Main Site are described. One (SAM-AP 6387) likely derives from ray II or ray III, whereas the other (SAM-AP 6388) is from the thumb. Both derive from a late adolescent or fully adult individual. They were recovered by H. Deacon from the same stratigraphic unit (submember W or possibly submember R) of the Shell and Sand Member of Cave 1, which places them between 100 and 90 ka. Both are comparatively small elements, and the possibility that they came from the same hand cannot be discounted at this time. These bones add to the meager and all too fragmentary postcranial human fossil sample from the Late Pleistocene of South Africa. These two specimens provide some additional evidence pertaining to the morphological attributes of the distal phalanges of the Middle Stone Age inhabitants of South Africa. Together with the distal pollical phalanx from Die Kelders (SAM-AP 6402), they are relatively small in comparison with homologs from recent human samples as well as Late Pleistocene specimens from Eurasia. Given their small sizes, the distal pollical phalanges from Klasies and Die Kelders are not dissimilar to Holocene Khoesan homologs. As expected, the Klasies elements differ noticeably from Neandertal homologs, especially in the narrowness of their shafts and distal tuberosities.

The Relation Between Calcaneus Stiffness Index as a Measure of Bone Density and Body Mass Index in an Egyptian Cohort

BACKGROUND

Obesity and osteoporosis are two conditions that are associated with morbidity and mortality; there is contradictory evidence regarding this association.

PURPOSE

The aim of the current study was to explore further the association between obesity and calcaneus stiffness index (CSI), as a measure of bone density, in a community-based cross-sectional study in an Egyptian population.

METHODS

A cross-sectional study was conducted among active subjects, aged ≥20 years old, over one year. CSI was measured by Quantitative ultrasound (QUS), in addition; QUS T-score and Z-score of the non-dominant heel scan were recorded.

RESULTS

Two hundred and eighty participants were recruited; 7 subjects were excluded because of Z score more than -2, mean age was 61 (± 11.9) years, and mean BMI was 29.7 (±5.6). Female participants were 77.7%, with mean of age 60.3 (± 11.6); and age range 20-82 years. Male participants were 22.3%, with mean of age 63.6 (± 12.7); and age range 30-80 years. Older subjects (>55 years) had significantly lower CSI and worse T-score than the younger subjects (P < 0.001 for both). In the younger age group, BMI was not significantly associated with CSI, even after adjustment for gender (P= 0.52). However, in the older age group, BMI was significantly associated with stiffness index (P= 0.049, O.R.= 1.73), even after adjustment for gender (P= 0.041, O.R.= 1.7).

CONCLUSION

Compared to young subjects, older subjects (≥55 years) had significantly lower bone strength as measured by CSI, and their BMI was significantly positively associated with bone density. In younger people (<55 years), BMI was not associated with bone strength.

Trabecular bone score and quantitative ultrasound measurements in the assessment of bone health in breast cancer survivors assuming aromatase inhibitors

PURPOSE

Aromatase inhibitors (AIs) represent the first-line adjuvant therapy for hormone receptor-positive breast cancer (BC) women. AIs have been associated with an increased rate of fractures. The aim of our study was to investigate trabecular bone score (TBS) and bone quantitative ultrasound (QUS) measurements as bone quality surrogates in AIs users.

METHODS

Sixty postmenopausal BC women starting AIs and forty-two controls (mean age 61.64 ± 8.33 years) were considered. Bone mineral density (BMD) at lumbar spine and femoral neck and TBS were measured by DXA; QUS-derived Amplitude-Dependent Speed of Sound (AD-SoS), Bone Transmission Time (BTT), and Ultrasound Bone Profile Index (UBPI) were assessed at phalangeal site; morphometric vertebral fractures (Vfx) by X-ray, serum bone-specific alkaline phosphatase (BSAP), and C-telopeptide of type 1 collagen (CTX) were also evaluated.

RESULTS

After 18 months, changes of TBS vs baseline were significantly different between AIs group and controls [Δ TBS - 2.2% vs - 0.4%, respectively, p = 0.001]. AD-SoS, BTT and UBPI values decreased only in AIs' group (- 3.7%, - 6.45%, -8.5%, vs baseline, respectively, p_all < 0.001). 3 Vfx occurred in AIs users and were associated with the greater TBS and AD-SoS modifications. In the AIs' group, ΔTBS was associated with ΔAD-SoS (r = 0.58, p < 0.001) and ΔUBPI (r = 0.415, p = 0.001), but not with ΔBMD. Moreover, ΔTBS was independently predicted by ΔAD-SoS, after correcting for BMD, CTX and BSAP level changes (β = 0.37, SE = 2.44, p < 0.001).

CONCLUSIONS

TBS and phalangeal QUS provide useful information related to bone quality in AI-treated BC survivors and could be considered for fracture risk evaluation.

Quantitative Ultrasound of Proximal Phalanxes in Childhood Acute Lymphoblastic Leukemia Survivors

Reduced bone mineral density (BMD) is a well-known complication in childhood acute lymphoblastic leukemia (ALL) survivors; the optimal method to assess BMD is still debated. We studied BMD by quantitative ultrasound (QUS) in 72 ALL survivors, and evaluated any correlation with cumulative doses of steroids and cytotoxic agents. Mean age at diagnosis was 61±45 months, while mean age at QUS was 318.3±129.6 months; mean period of follow-up was 41.2±37.8 months. Mean amplitude-dependent speed of sound z-score was -1.22±1.19. Ten survivors (13.8%) presented a z-score below -2 SD. A negative correlation was found between amplitude-dependent speed of sound z-score and age at diagnosis (P=0.01). A positive correlation was observed with length of follow-up (P=0.01). No correlation was found with cytotoxic drugs. This study represents the largest cohort of childhood ALL survivors studied by QUS. Our results suggest that QUS for its characteristics of being radiation free may be an effective option to assess BMD in pediatric age. In addition, our data outline the importance to improve the awareness about the specific expression of this complication in the pediatric age, concerning the major determinants of bone impairment, which are the disease itself and the phase of bone growth when the disease occurs.

The Prevalence of Osteopenia and Osteoporosis Among Malaysian Type 2 Diabetic Patients Using Quantitative Ultrasound Densitometer

Background:

Type 2 Diabetes Mellitus (T2DM) and osteoporosis are both chronic conditions and the relationship between them is complex.

Objective:

The aims of this study were to assess the prevalence of Low Bone Mineral density (LBMD, i.e., osteopenia and osteoporosis), as well as, the difference and associations between Quantitative Ultrasound Scan (QUS) parameters with socio-demographic data and clinical related data among T2DM in Penang, Malaysia.

Method:

An observational, cross-sectional study with a convenient sample of 450 T2DM patients were recruited from the outpatient diabetes clinic at Hospital Pulau Pinang (HPP) to measure Bone Mineral Density (BMD) at the heel bone using QUS. In addition, a self-reported structured questionnaire about the socio-demographic data and osteoporosis risk factors were collected. Moreover, the study included the retrospective collection of clinical data from patients’ medical records.

Results:

The mean value of T-score for normal BMD, osteopenic and osteoporotic patients’ were (-0.41±0.44), (-1.65±0.39) and (-2.76±0.27), respectively. According to QUS measurements, more than three quarters of T2DM patients (82%) were at high risk of abnormal BMD. The results showed that QUS scores were significantly associated with age, gender, menopausal duration, educational level and diabetic related data. Moreover, the QUS parameters and T-scores demonstrated significant negative correlation with age, menopausal duration, diabetic duration and glycaemic control, as well as, a positive correlation with body mass index and waist to hip ratio. The current study revealed that none of the cardiovascular disease risk factors appear to influence the prevalence of low BMD among T2DM Malaysian patients.

Conclusion:

The study findings revealed that the assessment of T2DM patients’ bone health and related factor are essential and future educational programs are crucial to improve osteoporosis management.

Constitutional bone impairment in Noonan syndrome

Noonan syndrome (NS) is an autosomal dominant trait characterized by genotypic and phenotypic variability. It belongs to the Ras/MAPK pathway disorders collectively named Rasopathies or neurocardiofaciocutaneous syndromes. Phenotype is characterized by short stature, congenital heart defects, facial dysmorphisms, skeletal and ectodermal anomalies, cryptorchidism, mild to moderate developmental delay/learning disability, and tumor predisposition. Short stature and skeletal dysmorphisms are almost constant and several studies hypothesized a role for the RAS pathway in regulating bone metabolism. In this study, we investigated the bone quality assessed by phalangeal quantitative ultrasound (QUS) and the metabolic bone profiling in a group of patients with NS, to determine whether low bone mineralization is primary or secondary to NS characteristics. Thirty-five patients were enrolled, including 20 males (55.6%) and 15 females (44.5%) aged 1.0-17.8 years (mean 6.4 ± 4.5, median 4.9 years). Each patients was submitted to clinical examination, estimation of the bone age, laboratory assays, and QUS assessment. Twenty-five percent of the cohort shows reduced QUS values for their age based on bone transmission time. Bone measurement were adjusted for multiple factors frequently observed in NS patients, such as growth retardation, delayed bone age, retarded puberty, and reduced body mass index, potentially affecting bone quality or its appraisal. In spite of the correction attempts, QUS measurement indicates that bone impairment persists in nearly 15% of the cohort studied. Our results indicate that bone impairment in NS is likely primary and not secondary to any of the phenotypic traits of NS, nor consistent with metabolic disturbances. © 2017 Wiley Periodicals, Inc.

Quantitative ultrasound and DXA measurements in aromatase inhibitor-treated breast cancer women receiving denosumab

PURPOSE

Denosumab has been proven to reduce fracture risk in breast cancer (BC) women under aromatase inhibitors (AIs). Quantitative ultrasound (QUS) provides information on the structure and elastic properties of bone. Our aim was to assess bone health by phalangeal QUS and by dual-energy X-ray absorptiometry (DXA), and to evaluate bone turnover in AIs-treated BC women receiving denosumab.

METHODS

35 Postmenopausal BC women on AIs were recruited (mean age 61.2 ± 4.5 years) and treated with denosumab 60 mg administered subcutaneously every 6 months. Phalangeal QUS parameters [Amplitude Dependent Speed of Sound (AD-SoS), Ultrasound Bone Profile Index (UBPI), Bone Transmission Time (BTT)] and DXA at lumbar spine and femoral neck were performed. Serum C-telopeptide of type 1 collagen (CTX) and bone-specific alkaline phosphatase (BSAP) were also measured. The main outcomes were compared with a control group not receiving denosumab (n = 39).

RESULTS

In patients treated with denosumab, differently from controls, QUS and DXA measurements improved after 24 months, and a reduction of CTX and BSAP was detected at 12 and 24 months in comparison to baseline (P < 0.05). The percent changes (Δ) of QUS measurements were significantly associated with ΔBMD at femoral neck, and ΔCTX and ΔBSAP were associated with ΔBMD at lumbar spine (r = -0.39, P = 0.02; r = -0.49, P = 0.01, respectively).

CONCLUSIONS

Denosumab preserves bone health as assessed by phalangeal QUS and DXA. Since inexpensive and radiation-free, phalangeal QUS may be considered in the follow-up of AIs-treated BC women receiving denosumab.

Imaging methods for bone mass evaluation during childhood and adolescence: an update

The objective of the work was to prepare an update on imaging methods for bone evaluation during childhood and adolescence. The text was based on original and review articles on imaging methods for clinical evaluation of bone mass in children and adolescents up to 20 years old. They were selected from BIREME and PUBMED by means of the following keywords: bone density; osteoporosis/diagnosis; densitometry; tomography; ultrasonography; magnetic resonance imaging; and radiogrammetry and published in Portuguese or English, in the last 10 years (2006-2016). The article was organized into topics with the description of peculiarities, advantages and disadvantages of each imaging method and their possible clinical applicability. Despite the emergence of new technologies, dual energy X-ray absorptiometry (DXA) remains the gold standard method for low bone mass diagnosis in all age groups. However, interpretation is complex in children and adolescents and demands skilled people. Quantitative computed tomography (QCT) [central QCT, peripheral QCT (pQCT) and high resolution-pQCT (HR-pQCT)] and magnetic resonance imaging (MRI) evaluate real bone density, but are not yet available for routine use. Quantitative bone ultrasound (QUS) shows good perspectives for its use in primary prevention actions. Automated radiogrammetry shows promise as a method able to flag individuals who might benefit from a complete bone assessment, but the clinical value of the measures still needs to be established.

A non-invasive prevention program model for the assessment of osteoporosis in the early postmenopausal period: a pilot study on FRAX(®) and QUS tools advantages

OBJECTIVE

The study analyses the performances of FRAX algorithm and quantitative ultrasound (QUS) tool in relationship to the dual-energy X-ray absorptiometry (DXA) categorization to identify patients at risk of osteoporosis during menopause and to reach new thresholds for recommending the first DXA examination.

DESIGN

Retrospective cohort study.

PATIENTS AND MEASUREMENTS

Two hundred eighty-two postmenopausal patients filled out a questionnaire which determined their FRAX index and performed a bone evaluation by QUS of the calcaneus to determine their stiffness index (SI). Thereafter, they underwent assessments by the gold-standard DXA bone examination.

RESULTS

Statistically significant correlations were observed between FRAX (calculated without BMD) and both QUS and DXA diagnosis. FRAX mean indices of risk corresponding to the diagnosis of osteoporosis by QUS and DXA were similar. Receiver operating characteristic (ROC) curve analysis showed that both FRAX and QUS tests were sufficiently accurate in predicting the alteration of bone mineral composition. The ROC curves of QUS allowed us to identify, in our population, SI cutoff for normal patients (SI > 90.5) and for patients having osteoporosis (SI < 78.5). We selected a cutoff screening value from FRAX ROC curve for major clinical fracture (2.94). The following diagnostic algorithm demonstrated that the use of FRAX test alone has a sensitivity of 85.3 % and a specificity of 33.8 % while the use of QUS exam alone showed a sensitivity of 81.3 % and a specificity of 45.1 %. When considering the capacity of QUS exam in combination with FRAX test, the final algorithm showed a sensitivity of 69.4 % and a specificity of 57.7 %.

CONCLUSIONS

The use of QUS test with adjusted cutoffs offers a similar performance to the FRAX test alone in terms of sensitivity. The combined use of the tests reduces the sensibility but increases the specificity and adds clinical information related to the bone status of the patient.

Quantitative ultrasound measurements of bone quality in female adolescents with idiopathic scoliosis compared to normal controls

OBJECTIVE

The aims of this study were to compare the speed-of-sound (SOS) between adolescent idiopathic scoliosis (AIS) patients and controls using quantitative ultrasound examination and to further analyze the relationship between the SOS and curve type, curve magnitude, maturation status and Risser's sign in AIS patients compared to controls.

METHODS

Seventy-eight female AIS patients and 58 healthy female controls 10 to 16 years of age were recruited to participate. Quantitative ultrasound measurements were performed at the non-dominant distal end of the radius. The standard method for estimating the SOS and z-score was used. Comparisons were made between the SOS values and z-score in AIS patients and age-matched Asian adolescents.

RESULTS

The SOS values of the patients were significantly lower than the controls (P < .01). The percentage of cases with low bone quality was 25% in the entire AIS sample. The prevalence of low bone quality in AIS patients was 20.5%. However, there were no correlations between the SOS and types of scoliosis (P > .05). The SOS values among different severity groups were significant, particularly between the 10° to 19° and 20° to 39° groups as well as between 10° to 19° and ≥40° groups. However, there was no significant correlation between the SOS and Cobb angles. Significant correlations were also found between the pre- and post-menarchy status in patients. There was a significant difference in the SOS values for different Rissers' signs (P < .05).

CONCLUSIONS

Compared to nonscoliotic controls, subjects with AIS had a generally lower SOS, indicating lower bone quality. The age, Risser's sign, or maturation status, may have an effect on the bone quality; however, the curve type and magnitude do not affect the bone quality. The results of this study indicate that slower bone maturation may affect the bone quality in adolescents with AIS.

Ultrasound to assess bone quality

Bone quality is determined by a variety of compositional, micro- and ultrastructural properties of the mineralized tissue matrix. In contrast to X-ray-based methods, the interaction of acoustic waves with bone tissue carries information about elastic and structural properties of the tissue. Quantitative ultrasound (QUS) methods represent powerful alternatives to ionizing x-ray based assessment of fracture risk. New in vivo applicable methods permit measurements of fracture-relevant properties, [eg, cortical thickness and stiffness at fragile anatomic regions (eg, the distal radius and the proximal femur)]. Experimentally, resonance ultrasound spectroscopy and acoustic microscopy can be used to assess the mesoscale stiffness tensor and elastic maps of the tissue matrix at microscale resolution, respectively. QUS methods, thus, currently represent the most promising approach for noninvasive assessment of components of fragility beyond bone mass and bone microstructure providing prospects for improved assessment of fracture risk.

Influence of porosity, pore size, and cortical thickness on the propagation of ultrasonic waves guided through the femoral neck cortex: a simulation study

The femoral neck is a common fracture site in elderly people. The cortical shell is thought to be the major contributor to the mechanical competence of the femoral neck, but its microstructural parameters are not sufficiently accessible under in vivo conditions with current X-ray-based methods. To systematically investigate the influences of pore size, porosity, and thickness of the femoral neck cortex on the propagation of ultrasound, we developed 96 different bone models (combining 6 different pore sizes with 4 different porosities and 4 different thicknesses) and simulated the ultrasound propagation using a finite-difference time-domain algorithm. The simulated single-element emitter and receiver array consisting of 16 elements (8 inferior and 8 superior) were placed at anterior and posterior sides of the bone, respectively (transverse transmission). From each simulation, we analyzed the waveform collected by each of the inferior receiver elements for the one with the shortest time of flight. The first arriving signal of this waveform, which is associated with the wave traveling through the cortical shell, was then evaluated for its three different waveform characteristics (TOF: time point of the first point of inflection of the received signal, Δt: difference between the time point at which the signal first crosses the zero baseline and TOF, and A: amplitude of the first extreme of the first arriving signal). From the analyses of these waveform characteristics, we were able to develop multivariate models to predict pore size, porosity, and cortical thickness, corresponding to the 96 different bone models, with remaining errors in the range of 50 μm for pore size, 1.5% for porosity, and 0.17 mm for cortical thickness.

Osteocyte-derived insulin-like growth factor I is essential for determining bone mechanosensitivity

This study sought to determine whether deficient Igf1 expression in osteocytes would affect loading-induced osteogenic response. Tibias of osteocyte Igf1 conditional knockout (KO) mice (generated by cross-breeding Igf1 floxed mice with Dmp1-Cre transgenic mice) and wild-type (WT) littermates were subjected to four-point bending for 2 wk. Microcomputed tomography confirmed that the size of tibias of conditional mutants was smaller. Loading with an equivalent loading strain increased periosteal woven bone and endosteal lamellar bone formation in WT mice but not in conditional KO mice. Consistent with the lack of an osteogenic response, the loading failed to upregulate expression of early mechanoresponsive genes (Igf1, Cox-2, c-fos) or osteogenic genes (Cbfa-1, and osteocalcin) in conditional KO bones. The lack of osteogenic response was not due to reduced osteocyte density or insufficient loading strain. Deficient osteocyte Igf1 expression reduced the loading-induced upregulation of expression of canonical Wnt signaling genes (Wnt10b, Lrp5, Dkk1, sFrp2). The loading also reduced (by 40%) Sost expression in WT mice, but the loading not only did not reduce but upregulated (~1.5-fold) Sost expression in conditional KO mice. Conditional disruption of Igf1 in osteocytes also abolished the loading-induced increase in the bone β-catenin protein level. These findings suggest an impaired response in the loading-induced upregulation of the Wnt signaling in conditional KO mice. In summary, conditional disruption of Igf1 in osteocytes abolished the loading-induced activation of the Wnt signaling and the corresponding osteogenic response. In conclusion, osteocyte-derived IGF-I plays a key determining role in bone mechanosensitivity.

A European multicenter comparison of quantitative ultrasound measurement variables: the OPUS study

Quantitative ultrasound (QUS) measurement variables vary between European countries in a different way to hip bone mineral density. Standardization of data can be achieved through statistical approaches to reduce any between-center differences in QUS measurement variables. However, further validation of this method is required before it can be widely applied.

INTRODUCTION

European between-center differences in hip bone mineral density (BMD) have been shown to exist; however, little is known about the geographical heterogeneity of QUS measurement variables. We aimed to examine the differences in QUS variables between three different European countries.

METHODS

Five calcaneal and phalangeal QUS devices in Sheffield, Aberdeen (UK), Kiel and Berlin (Germany), and three devices in Paris (France) were used to measure QUS variables in younger (n = 463, 20-39 years old) and older (n = 2,399, 55-79 years old) women participating in the European multicenter Osteoporosis and Ultrasound (OPUS) study. Broadband ultrasound attenuation, speed of sound, stiffness index, amplitude-dependent speed of sound, bone transmission time, and ultrasonic bone profiler index data were collected. Between-center differences were examined using ANOVA followed by post hoc Fisher's least significant difference tests, and ANCOVA with linear contrasts. p < 0.05 indicated statistical significance.

RESULTS

Between-center differences in nonstandardized QUS measurement variables existed for younger (p = 0.0023 to p < 0.0001) and older women (p < 0.001). Anthropometric characteristics exerted a significant influence on nonstandardized data (p = 0.045 to p < 0.001). However, following statistical standardization, based on height and weight or based on measurements made in young people, geographical heterogeneity in QUS measurement variables was no longer apparent.

CONCLUSIONS

QUS measurement variables vary between European countries in a different way to those for hip BMD. Standardization of data can be achieved through statistical approaches to reduce any between-center differences in QUS measurement variables. However, further validation of this method is required before it can be widely applied.

Phalangeal quantitative ultrasound in 1,719 children and adolescents with bone disorders

SUMMARY

We measured bone properties by phalangeal quantitative ultrasound in 1,719 pediatric patients with bone disorders, classifying them according to fracture status. Quantitative ultrasound discriminated fractured and nonfractured pediatric patients and enabled us to stratify fractured patients into classes according to the severity of the causative trauma (spontaneous, minimal trauma, appropriate trauma fractures).

INTRODUCTION

The correlation between quantitative bone measurements and fractures is poorly established in pediatric patients with bone disorders. We correlated phalangeal quantitative ultrasound (QUS) and fracture history in children and adolescents with bone disorders and evaluated the ability of QUS to recognize fractured patients.

METHODS

Amplitude-dependent speed of sound (AD-SoS) and bone transmission time (BTT) were measured in 1,719 pediatric patients with bone disorders and related to fracture history. The patients were classified as (1) spontaneously (77), (2) minimal trauma (101), or (3) appropriate trauma fractured (206), and (4) nonfractured (1,335). The likelihood of fracture according to QUS was calculated as odds ratio per SD decrease (OR/SD), and the effectiveness in discriminating fractured patients was evaluated by receiver operating characteristic (ROC) analysis. The influence of age, sex, puberty, height, and BMI was explored by respective adjustments and multiple logistic regression.

RESULTS

Fractured patients showed significantly reduced AD-SoS and BTT standard deviation score (-0.32 ± 1.54 and -0.78 ± 1.49) compared to nonfractured subjects (0.43 ± 1.63 and -0.11 ± 1.34). QUS measurements paralleled the causative trauma severity, ranging from the lowest values in spontaneously fractured patients to normal values in appropriate trauma fractured subjects. The OR/SD were increasingly higher in appropriate trauma fractured, minimal trauma fractured, and spontaneously fractured patients. At ROC analysis, both parameters proved to have significant discrimination power in recognizing spontaneously and minimal trauma-fractured patients.

CONCLUSIONS

QUS identifies fractured pediatric patients with bone disorders, reflecting the severity of the causative trauma with a high discrimination power for fragility fractures.

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.

Microwave sintering and in vitro study of defect-free stable porous multilayered HAp-ZrO2 artificial bone scaffold

Continuously porous hydroxyapatite (HAp)/t-ZrO2 composites containing concentric laminated frames and microchanneled bodies were fabricated by an extrusion process. To investigate the mechanical properties of HAp/t-ZrO2 composites, the porous composites were sintered at different temperatures using a microwave furnace. The microstructure was designed to imitate that of natural bone, particularly small bone, with both cortical and spongy bone sections. Each microchannel was separated by alternating lamina of HAp, HAp-(t-ZrO2) and t-ZrO2. HAp and ZrO2 phases existed on the surface of the microchannel and the core zone to increase the biocompatibility and mechanical properties of the HAp-ZrO2 artificial bone. The sintering behavior was evaluated and the optimum sintering temperature was found to be 1400 °C, which produced a stable scaffold. The material characteristics, such as the microstructure, crystal structure and compressive strength, were evaluated in detail for different sintering temperatures. A detailed in vitro study was carried out using MTT assay, western blot analysis, gene expression by polymerase chain reaction and laser confocal image analysis of cell proliferation. The results confirmed that HAp-ZrO2 performs as an artificial bone, showing excellent cell growth, attachment and proliferation behavior using osteoblast-like MG63 cells.

Relative contributions of porosity and mineralized matrix properties to the bulk axial ultrasonic wave velocity in human cortical bone

Velocity of ultrasound waves has proved to be a useful indicator of bone biomechanical competence. A detailed understanding of the dependence of ultrasound parameters such as velocity on bone characteristics is a key to the development of bone quantitative ultrasound (QUS). The objective of this study is to investigate the relative contributions of porosity and mineralized matrix properties to the bulk compressional wave velocity (BCV) along the long bone axis. Cross-sectional slabs from the diaphysis of four human femurs were included in the study. Seven regions of interest (ROIs) were selected in each slab. BCV was measured in through-transmission at 5 MHz. Impedance of the mineralized matrix (Z(m)) and porosity (Por) were obtained from 50 MHz scanning acoustic microscopy. Por and Z(m) had comparable effects on BCV along the bone axis (R=-0.57 and R=0.72, respectively).

Ultrasound for the assessment of bone quality in preterm and term infants

OBJECTIVE

As 80% of intrauterine bone mineralization takes place during the last trimester of pregnancy, preterm infants should be supplemented postnatally with optimal doses of calcium, phosphate and vitamin D. Calcium and phosphate excretion in the urine may be used to monitor individual mineral requirements, but are sometimes difficult to interpret. The objective of this study was to assess the value of quantitative ultrasound (QUS) for the analysis of bone status in neonates.

STUDY DESIGN

All admissions to three independent tertiary neonatal intensive care units were studied. In 172 preterm and term infants with a gestational age between 23 and 42 weeks (mean 33.8±5.0) and a birth weight from 405 to 5130 g (mean 2132±1091 g) bone status was evaluated prospectively by quantitative ultrasound velocity using a standardized protocol. Infants were followed in regular intervals up to their first discharge home. While measurements were conducted in weekly intervals initially (n=55), 2-week intervals were regarded as sufficient thereafter due to limited changes in QUS values within the shorter period. Infants with a birth weight below 1500 g were followed during outpatient visits until up to 17 months of age.

RESULT

The intra-individual day-to-day reproducibility was 0.62%. QUS-values from the first week of life correlated significantly with gestational age and birth weight (r=0.5 and r=0.6; P<0.001). Small-for-gestational-age infants showed lower values for QUS than appropriate-for-gestational-age infants allowing for their gestational age. Follow-up measurements correlated positively with age and weight during the week of measurement (r=0.2 and r=0.4; P=0.001). Comparing bone quality at 40 weeks of age in infants born at term versus infants born at 24 to 28 weeks, preterm infants showed significantly lower QUS than term infants (P<.0001).There was a significant correlation of QUS with serum alkaline phosphatase (P=0.003), the supplementation with calcium, phosphate and vitamin D (P< 0.001 each), as well as risk factors for a reduced bone mineralization. No correlation was found between QUS and calcium or phosphate concentration in serum or urine.

CONCLUSION

QUS is a highly reproducible, easily applicable and radiation-free technique that can be used to monitor bone quality in individual newborns. Further prospective randomized-trials are necessary to evaluate, if therapeutic interventions based on QUS are able to prevent osteopenia of prematurity.

The association of body composition and sex hormones with quantitative ultrasound parameters at the calcaneus and phalanxes in elderly women

We investigated the associations of body composition and sex hormones with quantitative ultrasound (QUS) parameters carried out at different skeletal sites. In 897 postmenopausal women (64.1 ± 6.6 years) we measured QUS at the calcaneus (stiffness) by Achilles-GE and at phalanxes (amplitude-dependent speed of sound [AD-SOS], bone transmission time [BTT], and ultrasound bone profile index [UBPI]) by Bone Profiler-IGEA. In all subjects we measured fat mass (FM), lean mass (LM), android fat, and gynoid fat by DXA. In all subjects we also assessed serum testosterone (T), estradiol (E(2)), sex-hormone binding globulin, free estrogen index (FEI), free androgen index, 25-hydroxyvitamin D (25OHD), bone alkaline phosphatase (B-ALP), and type I collagen β carboxy telopeptide. Both E(2) and FEI showed weak but significant correlations with stiffness and QUS parameters at phalanxes. No significant relationships were found between T and QUS. BMI and LM were positively correlated with stiffness (r = 0.14 and r = 0.17, respectively), whereas BMI and FM showed negative correlations with AD-SOS, BTT, and UBPI. 25OHD showed positive relationships with stiffness and QUS at phalanxes. In multivariate models LM and age were associated with stiffness whereas E(2) and age were significant predictors of BTT. AD-SOS was negatively associated with FM, B-ALP, and age but positively with E(2) and 25OHD. In postmenopausal women QUS parameters at the calcaneus and at phalanxes are significantly, but diversely, associated with body composition, sex hormones, 25OHD, and bone turnover markers.

Epidemiology of osteoporosis in an isolated Sardinian population by using quantitative ultrasound

This study aimed at estimating the prevalence of osteoporosis and osteopenia in a Sardinian isolated population using hand quantitative ultrasound and at investigating the associated factors. The authors utilized a subset of data from a large population-based epidemiologic survey carried out in the Ogliastra region of Sardinia between 2003 and 2008. The sample consists of 6,326 men and women aged ≥30 years, who underwent quantitative ultrasound at the phalanges, bioelectrical impedance, anthropometric measurements, blood tests, and a standardized epidemiologic questionnaire collecting sociodemographic, lifestyle, medical, physiologic, and pharmacologic data. The T-score thresholds for amplitude-dependent speed of sound of -3.2 standard deviations and between -3.2 and -1 standard deviations were used to diagnose osteoporosis and osteopenia, respectively. Prevalence of osteoporosis was 17.0% in women and 5.2% in men. Logistic regression analysis revealed that factors associated with osteoporosis were age, anthropometric and bioimpedance measures, alkaline phosphatase levels, and menopause in women. High education, exercise, and beer consumption seem to be protective factors, whereas a family history of osteoporosis is a risk factor. Results show that osteoporosis in this population is comparable with that found in different countries, suggesting that quantitative ultrasound could be used more widely to detect high-risk individuals for preventing osteoporotic fractures.

Fabric dependence of quasi-waves in anisotropic porous media

Assessment of bone loss and osteoporosis by ultrasound systems is based on the speed of sound and broadband ultrasound attenuation of a single wave. However, the existence of a second wave in cancellous bone has been reported and its existence is an unequivocal signature of poroelastic media. To account for the fact that ultrasound is sensitive to microarchitecture as well as bone mineral density (BMD), a fabric-dependent anisotropic poroelastic wave propagation theory was recently developed for pure wave modes propagating along a plane of symmetry in an anisotropic medium. Key to this development was the inclusion of the fabric tensor--a quantitative stereological measure of the degree of structural anisotropy of bone--into the linear poroelasticity theory. In the present study, this framework is extended to the propagation of mixed wave modes along an arbitrary direction in anisotropic porous media called quasi-waves. It was found that differences between phase and group velocities are due to the anisotropy of the bone microarchitecture, and that the experimental wave velocities are more accurately predicted by the poroelastic model when the fabric tensor variable is taken into account. This poroelastic wave propagation theory represents an alternative for bone quality assessment beyond BMD.

Quantitative ultrasound normative reference data for community-dwelling white and black females in the United States

Quantitative ultrasound (QUS) race-specific normative reference data are not available for accurate calculation of Z-scores. The primary aims of this study were (1) to develop a race-specific QUS reference database for white and black females and to compare estimated fracture risk between these 2 racial groups and (2) to compare stiffness index (SI) values of white females in this study to manufacturer-obtained values. Subjects included 1111 females (31% black), aged 20-85 yr (52 ± 19 yr), with a mean SI score of 93.7 ± 20.1. White females, aged 20-39 yr (n=213), were used to calculate T-scores, whereas Z-scores were age and race specific. Black females had significantly higher SI scores than white females (p<0.001). White females aged 50+ yr in this study had significantly higher SI scores compared with manufacturer-derived values. Results highlight the need for population- and race-specific normative data when using QUS as a screening tool for identifying high fracture risk.

Impact of metabolic control on bone quality in phenylketonuria and mild hyperphenylalaninemia

OBJECTIVES

A reduction of bone mineral density of unknown etiology has been reported in phenylketonuria (PKU) by radiological techniques, whereas no data on bone density in mild hyperphenylalaninemia (HPA) are available. We aimed to assess bone condition in PKU and HPA by quantitative ultrasound (QUS), taking into account patients' clinical and biochemical features.

PATIENTS AND METHODS

Phalangeal QUS has been used for bone assessment in 78 patients affected by PKU (n = 42) or mild HPA (n = 36). For each patient, blood phenylalanine concentrations in the 2 years before the study have been recorded and related to bone assessment.

RESULTS

Overall normal bone quality has been observed in the whole study group (AD-SoS standard deviation score [SDS] 0.25 ± 1.29; BTT SDS -0.13 ± 1.08). PKU adolescents (age older than 15 years, AD-SoS SDS -0.54 ± 1.33; BTT SDS -0.85 ± 1.21) and patients with poor compliance with treatment (blood phenylalanine >10 mg/dL, AD-SoS SDS -0.47 ± 1.39; BTT SDS -0.97 ± 1.14) showed lower BTT SDS with respect to normal population (P = 0.003 and P < 0.001, respectively). Patients with PKU with good compliance with treatment (blood phenylalanine < 10 mg/dL, AD-SoS SDS 0.65 ± 1.33; BTT SDS 0.15 ± 0.94) and patients with mild HPA (AD-SoS SDS 0.44 ± 1.06 and BTT SDS 0.19 ± 0.85) showed normal bone mineral density and cortical thickness.

CONCLUSIONS

Good compliance with treatment in PKU during adolescence and adulthood is desirable because diet discontinuation is associated with bone loss. Mild HPA seems not to be complicated by bone damage.

Fabric dependence of wave propagation in anisotropic porous media

Current diagnosis of bone loss and osteoporosis is based on the measurement of the bone mineral density (BMD) or the apparent mass density. Unfortunately, in most clinical ultrasound densitometers: 1) measurements are often performed in a single anatomical direction, 2) only the first wave arriving to the ultrasound probe is characterized, and 3) the analysis of bone status is based on empirical relationships between measurable quantities such as speed of sound (SOS) and broadband ultrasound attenuation (BUA) and the density of the porous medium. However, the existence of a second wave in cancellous bone has been reported, which is an unequivocal signature of poroelastic media, as predicted by Biot's poroelastic wave propagation theory. In this paper, the governing equations for wave motion in the linear theory of anisotropic poroelastic materials are developed and extended to include the dependence of the constitutive relations upon fabric-a quantitative stereological measure of the degree of structural anisotropy in the pore architecture of a porous medium. This fabric-dependent anisotropic poroelastic approach is a theoretical framework to describe the microarchitectural-dependent relationship between measurable wave properties and the elastic constants of trabecular bone, and thus represents an alternative for bone quality assessment beyond BMD alone.

Bone impairment in phenylketonuria is characterized by circulating osteoclast precursors and activated T cell increase

BACKGROUND

Phenylketonuria (PKU) is a rare inborn error of metabolism often complicated by a progressive bone impairment of uncertain etiology, as documented by both ionizing and non- ionizing techniques.

METHODOLOGY

Peripheral blood mononuclear cell (PBMC) cultures were performed to study osteoclastogenesis, in the presence or absence of recombinant human monocyte-colony stimulating factor (M-CSF) and receptor activator of NFκB ligand (RANKL). Flow cytometry was utilized to analyze osteoclast precursors (OCPs) and T cell phenotype. Tumour necrosis factor α (TNF-α), RANKL and osteoprotegerin (OPG) were quantified in cell culture supernatants by ELISA. The effects of RANKFc and anti-TNF-α antibodies were also investigated to determine their ability to inhibit osteoclastogenesis. In addition, bone conditions and phenylalanine levels in PKU patients were clinically evaluated.

PRINCIPAL FINDINGS

Several in vitro studies in PKU patients' cells identified a potential mechanism of bone formation inhibition commonly associated with this disorder. First, PKU patients disclosed an increased osteoclastogenesis compared to healthy controls, both in unstimulated and M-CSF/RANKL stimulated PBMC cultures. OCPs and the measured RANKL/OPG ratio were higher in PKU patients compared to healthy controls. The addition of specific antagonist RANKFc caused osteoclastogenesis inhibition, whereas anti-TNF-α failed to have this effect. Among PBMCs isolated from PKU patients, activated T cells, expressing CD69, CD25 and RANKL were identified. Confirmatory in vivo studies support this proposed model. These in vivo studies included the analysis of osteoclastogenesis in PKU patients, which demonstrated an inverse relation to bone condition assessed by phalangeal Quantitative Ultrasound (QUS). This was also directly related to non-compliance to therapeutic diet reflected by hyperphenylalaninemia.

CONCLUSIONS

Our results indicate that PKU spontaneous osteoclastogenesis depends on the circulating OCP increase and the activation of T cells. Osteoclastogenesis correlates with clinical parameters, suggesting its value as a diagnostic tool for an early assessment of an increased bone resorption in PKU patients.

Femur ultrasound (FemUS)--first clinical results on hip fracture discrimination and estimation of femoral BMD

SUMMARY

A quantitative ultrasound (QUS) device for measurements at the proximal femur was developed and tested in vivo (Femur Ultrasound Scanner, FemUS). Hip fracture discrimination was as good as for DXA, and a high correlation with hip BMD was achieved. Our results show promise for enhanced QUS-based assessment of osteoporosis.

INTRODUCTION

Dual X-ray absorptiometry (DXA) at the femur is the best predictor of hip fractures, better than DXA measurements at other sites. Calcaneal quantitative ultrasound (QUS) can be used to estimate the general osteoporotic fracture risk, but no femoral QUS measurement has been introduced yet. We developed a QUS scanner for measurements at the femur (Femur Ultrasound Scanner, FemUS) and tested its in vivo performance.

METHODS

Using the FemUS device, we obtained femoral QUS and DXA on 32 women with recent hip fractures and 30 controls. Fracture discrimination and the correlation with femur bone mineral density (BMD) were assessed.

RESULTS

Hip fracture discrimination using the FemUS device was at least as good as with hip DXA and calcaneal QUS. Significant correlations with total hip bone mineral density were found with a correlation coefficient R (2) up to 0.72 and a residual error of about one half of a T-score in BMD.

CONCLUSIONS

QUS measurements at the proximal femur are feasible and show a good performance for hip fracture discrimination. Given the promising results, this laboratory prototype should be reengineered to a clinical applicable instrument. Our results show promise for further enhancement of QUS-based assessment of osteoporosis.

Bone quantitative ultrasound in congenital and acquired childhood multiple pituitary failure

The aim of the present study is to investigate bone status by phalangeal quantitative ultrasound (QUS) in a cohort of hypopituitaric pediatric subjects, and to relate measurement outcome to their clinical, laboratory, and therapeutical features. Forty-three hypopituitaric children were submitted to bone measurement by QUS with DBM sonic bone profiler 1200 (IGEA, Carpi, Modena, Italy). This method measures bone transmission time (BTT) and amplitude-dependent speed of sound (AD-SoS) of an ultrasound beam crossing the first four phalanges of the hand and provides respective standard deviation scores (SDS). These two parameters provide information on bone mineral density and structure. Clinical, laboratory and therapeutical features were considered to look for correlations. Overall BTT and AD-SoS SDS were significantly reduced (-0.87 +/- 1.52, p = 0.001, and -0.97 +/- 1.56, p = 0.001) as well as respective height- or bone age-corrected SDS. Bone condition proved significantly worse in subjects with higher number of hormonal deficiencies (p = 0.001 for both parameters) and in those with acquired hypopituitarism (p = 0.020 for BTT and p = 0.010 for AD-SoS) than in those with congenital forms. In participants under growth hormone (GH) treatment, regression analysis revealed that QUS measurement outcome was significantly associated with age at GH therapy start (p = 0.001), time interval before therapy initiation (p = 0.011), treatment duration (p = 0.007) and administered dosage (p = 0.036). Our data show that childhood hypopituitarism is associated with bone morbidity, detectable at QUS measurement independently of potential confounders as stature and bone age. Skeletal impairment is related to acquired hypopituitarism, number of hormonal deficiencies and duration of disease before replacement therapies, whereas GH treatment duration and doses are associated with a better skeletal condition. Phalangeal QUS measurements of BTT and AD-SoS promise as a reliable method for obtaining quantitative measurements of bone disease in individuals with hypopituitarism but more studies are needed for verification.

Potential of first arriving signal to assess cortical bone geometry at the Hip with QUS: a model based study

There is evidence that quantitative ultrasound (QUS) at the proximal femur involves waves propagating circumferentially in the cortical shell. These waves, in theory, convey information on bone geometrical and material characteristics and thus have the potential to improve fracture risk prediction. In this work, the time-of-flight (TOF) of the first arriving signal (FAS) that corresponds to waves propagating circumferentially is considered. The relationships between the TOF of the FAS and geometrical features of the femoral neck are investigated. Five neck cross-sections from 11 human femurs from females (>65y) were extracted from 3-D X-ray quantitative computed tomography (XR-QCT) datasets. Geometrical parameters including cross-sectional area (CSA), minimum moment of inertia (I(min)) and section modulus (Z) were computed from femoral neck cross-section images. Two-dimensional numerical simulation of US propagation through femoral neck was performed and TOF of the FAS was estimated. TOF was best correlated with I(min): R(2)=0.82 (p=10(-4); RMSE=1390mm(4) [13%]) in the region between proximal and mid-femoral neck and with Z: R(2)=0.55 (p<10(-2); RMSE=480mm(3) [17%]) and CSA: R(2)=0.62 (p<5.10(-3); RMSE=22mm(2) [7%]) in the mid-femoral neck. The results suggest that QUS has the potential to assess proximal femur strength based on estimates of geometrical properties of the cortical shell.

Cortical thickness and medullary canal dimensions of the bone phalanx are predicted by quantitative ultrasound parameters

The aim of the study was to investigate the relationship between quantitative ultrasound (QUS) parameters extracted from the analysis of the ultrasound (US) signal and the geometric properties of the bones. One hundred and one subjects in the age range of 20-7 4yr (mean: 52+/-12 yr) have been measured by QUS at the phalanges for the evaluation of amplitude-dependent speed of sound (AD-SoS), bone transmission time (BTT), US peak amplitude (UPA), signal dynamic (SDY), slope, energy, and fast wave amplitude (FWA). Hand radiograph, lumbar spine dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT), and femoral neck DXA forearm peripheral QCT were performed on all patients. BTT is related to cortical thickness (CTh) (r=0.62, p<0.0001), and FWA is related to medullary canal thickness (r=-0.64, p<0.0001). Other parameters are related to both medullary canal thickness (AD-SoS: r=-0.21; UPA: r=-0.53; SDY: r=-0.56; slope: r=-0.64; energy: r=-0.44, p<0.05) and CTh (AD-SoS: r=0.54, p<0.0001; UPA: r=0.51; SDY: r=0.38; slope: r=0.32; energy: r=0.56, p<0.001). Linear multivariate models indicate that BTT, UPA, and energy measured at the phalanges carry independent information on CTh of the bone, whereas FWA, SDY, and slope are related only to medullary canal thickness.

Prospective bone ultrasound patterns during childhood acute lymphoblastic leukemia treatment

OBJECTIVE

Bone impairment is a well-known complication in childhood acute lymphoblastic leukemia (ALL) survivors but less is known about bone dynamics during ALL therapy. We longitudinally assessed by Quantitative Ultrasound (QUS) skeletal modifications during this treatment.

MATERIALS AND METHODS

Forty-four newly diagnosed ALL children underwent bone measurement by QUS parameters BTT (Bone Transmission Time) and AD-SoS (Amplitude-Dependent Speed of Sound), mainly reliant on bone density and cortical thickness, respectively. Measurements were performed at diagnosis, and 6, 12, and 24 months thereafter. The occurrence of skeletal complications such as fractures, vertebral collapse, osteonecrosis, and osteopenia was related to measurement outcome.

RESULTS

A rapid deterioration of bone properties measured by BTT and AD-SoS was evident in the first semester of therapy (p<0.001). Subsequently, the next measurements were characterized by progressive uncoupling of the two QUS parameters (p<0.001). These were both significantly reduced at the end of therapy (p<0.001). Twelve subjects with in-treatment skeletal complications displayed an almost two-fold decrease of both parameters (p<0.001). BTT decreasing more than 1 Standard Deviation (SD) over 6 months of therapy was able to predict skeletal complication occurrence (p<0.001).

CONCLUSION

This report represents the largest longitudinal cohort systematically submitted to bone condition assessment from the beginning to the end of therapy for childhood ALL. Bone deterioration occurs early and persists throughout therapy, consistent with bone properties uncoupling. This pattern possibly reflects an initial impairment of both mineral density and cortical thickness with a subsequent recovery of this latter. QUS permits an early detection of bone deterioration and related skeletal complications in childhood ALL.

Genetic architecture of hand quantitative ultrasound measures: a population-based study in a Sardinian genetic isolate

It is now recognized that quantitative ultrasound (QUS) measures may predict osteoporotic fracture risk independently of bone mineral density. Although many studies have examined genetic and environmental components of bone mineral density and calcaneal QUS measures, few of them were addressed to phalangeal QUS phenotypes, and none to graphic trace parameters. This study aims to evaluate the relative contribution of genetics in the expression of phalangeal QUS traits in the adult healthy population of a Sardinian genetic isolate. Our sample includes 6056 men and women aged 30-103 years, from 43 extended pedigrees recruited in 10 villages of Ogliastra region in occasion of a large epidemiologic survey. Amplitude-dependent speed of sound (AD-SoS), fast wave amplitude (FWA), signal dynamic (SDy), bone transmission time (BTT) and ultrasound bone profile index (UBPI) were obtained from the non-dominant hand using the IGEA DBM Sonic Bone Profiler. These phenotypes were first regressed on age, anthropometric and bioimpedance measures, serum calcium, phosphorus and alkaline phosphatase, alcohol and caffeine consumption, smoking status, exercise and also months since menopause and estrogens use in women. Adjusted QUS parameters were then analyzed by univariate and bivariate variance component models to obtain heritability estimates and genetic and environmental correlations. QUS parameters were correlated to age, anthropometric and bioimpedance measures, serum phosphorus, alkaline phosphatase and to reproductive history and menopause in women. All phenotypes demonstrated substantial heritabilities ranging from 0.29+/-0.03 for SDy to 0.55+/-0.03 for FWA. Proportion of variance due to all covariates ranged from 36% for SDy to 59% for BTT. Many significant genetic and environmental correlations were found between the different QUS measures. In this study, genetic factors appear to play a relevant role in determining hand QUS measures even when taking into account various important environmental factors. Furthermore, the modest genetic correlations may imply the existence of partially unique sets of genes affecting different QUS traits, thus suggesting that QUS parameters measure different properties of bone tissue.

Analysis of quantitative ultrasound graphic trace and derived variables assessed at proximal phalanges of the hand in healthy subjects and in patients with cerebral palsy or juvenile idiopathic arthritis. A pilot study

Amplitude-dependent speed of sound (AD-SoS) and bone transmission time (BTT) are the quantitative ultrasound (QUS) variables usually assessed at proximal phalanges of the hand to estimate bone mineral status. The aim of the study was to provide a reference database for some additional QUS variables reflecting morphology of the ultrasound graphic trace according to gender, age, height, weight, and body mass index (BMI), and to assess their clinical usefulness. Fifty-two patients (age 3.1-20.9 years) affected by cerebral palsy with spastic tetraplegia (CPST, n=38) or polyarticular active juvenile idiopathic arthritis (JIA, n=14) were examined. In addition to AD-SoS and BTT, two QUS variables derived from the morphological analysis of ultrasound graphic trace, such as energy, extrapolated from the area under the ultrasound signal received, and weighted-slope (W-slope), derived from the angular coefficient of the regression line fitting the top point of the peaks of the ultrasound signal, were measured by phalangeal QUS (DBM Sonic, IGEA). The values of all the QUS variables measured in the patients were compared with our own sex- and age-reference values (n=1083, 587 males and 496 females, aged 3-21 years). The mean values of AD-SoS, BTT, energy, and W-slope were reduced (P<0.0001) in patients as a whole compared with normative data (-2.4+/-1.2, -2.7+/-1.5, -2.5+/-1.1, -2.5+/-1.1 Z-score, respectively). Fractured patients showed lower (P<0.001-P<0.0001) values of the QUS variables than fracture-free patients (AD-SoS, -3.3+/-1.2 and -1.8+/-0.9; BTT, -3.9+/-1.7 and -1.8+/-1.1; energy, -3.2+/-1.2 and -2.2+/-0.7; W-slope, -3.4+/-1.4 and -2.2+/-0.9 Z-score, respectively). There was no difference (P=NS) between patients with CPST and those with JIA. Age and height were positively correlated with all the QUS variables (r=0.55-0.79, P<0.01-P<0.0001). QUS variables were positively correlated among them (r=0.74-0.94, P<0.0001). Age and number of fractures were independent predictors of the QUS variables (coefficients: AD-SoS, 11.466 and -17.642; BTT, 0.049 and -0.045; energy, 1.072 and -1.303; W-slope, 0.046 and -0.067; respectively). In conclusion, measurement of QUS variables derived from the morphological analysis of the ultrasound signal could give additional information in estimating bone mineral status in children and adolescents, probably reflecting some aspect related to bone structure.

Good maintenance of physical benefits in a 12-month exercise and nutritional intervention by voluntary, home-based exercise: a 6-month follow-up of a randomized controlled trial

We assessed the maintenance of physical benefits in a 12-month exercise and nutritional intervention in postmenopausal women (55-75 years of age) after 6-month postintervention follow-up by voluntary, home-based exercise, and examined whether physical factors responded differently to high or low exercise frequency during the 6-month postintervention period. Forty-five women completed the 12-month intervention program, followed by 6-month cessation of intervention, and were compared with 19 matched controls. Twenty-one of the former exercisers reported that they continued exercise training at least 30 min at least 3 days/week (high-frequency exerciser, HFE), while the remaining 24 former exercisers reported that they had done exercise training at least 30 min twice per week or less during the postintervention follow-up (low-frequency exerciser, LFE). The following items were measured at baseline, 12, and 18 months: bone strength, CS-30 test, 10-m obstacle walk, whole-body reaction time, one-leg stance, and grip strength. After 6-month postintervention follow-up, the beneficial effect on bone was not fully maintained. These benefits in physical performance obtained in the 12-month intervention program, except one-leg stance, were fully maintained for 6 months by voluntary, home-based exercise. The gained benefit in one-leg stance was not fully maintained; LFE showed a significant decrease over the 6-month postintervention follow-up period, suggesting that continued exercise training of at least 30 min at least 3 days/week is required to maintain the balance benefit. These findings suggest that a continued exercise program of voluntary, home-based exercise may be effective to maintain the physical benefits of exercise intervention that may lower fracture risk in later life.

Quantitative ultrasound at the phalanges in monitoring alendronate therapy

This study evaluated the efficacy of quantitative ultrasound (QUS) at the phalanges in monitoring alendronate treatment. Seventy-nine postmenopausal women were enrolled: 46 subjects entered therapy with alendronate, the remaining 33 did not follow any therapeutic regimen. All subjects underwent phalangeal ultrasound measurement before starting treatment and after 12 mo. Two QUS parameters were measured: AD-SoS (Amplitude Dependent Speed of Sound) in m/s, and BTT (Bone Transmission Time) in micros. Mean age of subjects at the beginning of the study was 58.7 +/- 6.5 y, mean BMI was 26.6 +/- 4.4 kg/m(2), mean time since menopause was 6.7 +/- 5.0 y; no significant differences could be observed between the groups (p > 0.05). At 12-mo follow-up a significant increase of both QUS parameters was observed: +18.8 +/- 24.4 m/s for AD-SoS, p < 0.0001; +0.05 +/- 0.08 micros for BTT, p < 0.001. In the nontreated group AD-SoS was stable (+1.0 +/- 33.7 m/s), as well as BTT (-0.07 +/- 0.25 micros), p = n.s. for both. In the treated group the percentage of responders was 65.2% for AD-SoS and 50.0% for BTT. The percentage of non responders was 13% for AD-SoS and 15.2% for BTT. The results confirm that the effect of alendronate treatment may be suggested by QUS at the phalanges after 12 mo of treatment.

Quantitative ultrasound in the management of osteoporosis: the 2007 ISCD Official Positions

Dual-energy X-ray absorptiometry (DXA) is commonly used in the care of patients for diagnostic classification of osteoporosis, low bone mass (osteopenia), or normal bone density; assessment of fracture risk; and monitoring changes in bone density over time. The development of other technologies for the evaluation of skeletal health has been associated with uncertainties regarding their applications in clinical practice. Quantitative ultrasound (QUS), a technology for measuring properties of bone at peripheral skeletal sites, is more portable and less expensive than DXA, without the use of ionizing radiation. The proliferation of QUS devices that are technologically diverse, measuring and reporting variable bone parameters in different ways, examining different skeletal sites, and having differing levels of validating data for association with DXA-measured bone density and fracture risk, has created many challenges in applying QUS for use in clinical practice. The International Society for Clinical Densitometry (ISCD) 2007 Position Development Conference (PDC) addressed clinical applications of QUS for fracture risk assessment, diagnosis of osteoporosis, treatment initiation, monitoring of treatment, and quality assurance/quality control. The ISCD Official Positions on QUS resulting from this PDC, the rationale for their establishment, and recommendations for further study are presented here.

The influence of gluten free diet on quantitative ultrasound of proximal phalanxes in children and adolescents with type 1 diabetes mellitus and celiac disease

A reduced bone mineral density has been reported in patients with untreated celiac disease (CD) as well as in patients with poorly controlled type 1 diabetes mellitus (T1DM). The aim of this study was to evaluate the bone mineral status by phalangeal quantitative ultrasound in 52 children and adolescents with both diseases (mean age 13.3+/-4.9 years). As a control group 50 patients with T1DM and no CD (age 12.2+/-4.0 years) were studied. The following bone parameters, amplitude-dependent speed of sound (AD-SoS) and bone transmission time (BTT) were considered and expressed as z score. Compliance to gluten free diet and long term glycemic control (mean of four determinations of HbA1c in the last year) were also assessed. The lowest mean AD-SoS z score values were found in patients with T1DM and CD, who reported transgressions to gluten free diet and exhibited positivity for serum anti-tissue transglutaminase antibodies (tTG) and/or endomysial antibodies (EmA), compared with patients with occasional transgressions but negative for anti-tTG and/or -EmA, patients strictly adherent to the diet, and patients who suffered only from diabetes (ANOVA p=0.021). No difference was found between patients with diabetes alone and patients with both diseases strictly adherent to gluten free diet. Prevalence of osteopenia (z AD-SoS values <-2 SD) was higher in patients with T1DM and CD and poor compliance to the diet (45.5%) compared with patients with T1DM (8%) or patients with both diseases strictly compliant to diet (12.9%) (p=0.015). A negative correlation between Ad-SoS z score and HbA1c (r -0.236, p=0.036) was found when patients with T1DM and patients with T1DM and CD, who strictly adhere to the diet, were pooled. In conclusion the quality of bone as assessed by phalangeal ultrasound in patients with T1DM and CD, who strictly adhere to gluten free diet, is similar to that found in T1DM patients. A higher prevalence of osteopenia is present in patients with both diseases who reported habitual transgressions to gluten free diet. The gluten free diet, as well as the optimization of glycemic control, plays an important role in preventing the osteopenic status caused by the clustering of these two chronic diseases.

Phalangeal quantitative ultrasound in children with phenylketonuria: a pilot study

Bone alterations in phenylketonuria (PKU) have been detected, especially with increasing age, in several studies by using different radiologic techniques. Quantitative ultrasound (QUS) assesses skeletal status by measuring the amplitude-dependent speed of sound (AD-SoS) and the bone transmission time (BTT), mainly dependent on mineral density and cortical thickness. Bone condition in 30 children and adolescents (mean age 15.1 +/- 6.4 y) affected by PKU was evaluated by phalangeal QUS, considering its relationship with their clinical, biochemical and therapeutic features. Measured AD-SoS Z-Score and BTT Z-Score were 0.27 +/- 1.42 and -0.26 +/- 1.21, respectively. In patients with previous fractures, the two QUS parameters were lower than in patients without history of fracture (p < 0.001 and p = 0.006, respectively). AD-SoS Z-Score and BTT Z-Score were negatively correlated with plasma phenylalanine (Phe) concentration in the year before QUS (p = 0.005 and p < 0.001, respectively) and with age (p < 0.001 for both parameters). These results parallel the previous findings obtained by different radiologic tools and suggest phalangeal QUS as an attractive option for the regular evaluation and longitudinal monitoring of bone condition in children and adolescents affected by PKU.

Influence of density, elasticity, and structure on ultrasound transmission through trabecular bone cylinders

The aim of this in vitro study is to evaluate the potentiality of quantitative ultrasound (QUS) to separate information on density, elasticity, and structure on specimens of trabecular bone. Fifteen cylinders of spongy bone extracted from equine vertebrae were progressively demineralized and subjected to QUS, micro computed tomography (muCT), Dual energy X-ray absorptiometry (DXA) at various mineralization levels. Eventually all cylinders underwent a compression test to calculate the Young's modulus. Correlation analysis shows that speed of sound (SOS) is strictly associated to bone mineral density (BMD), Young's modulus, and all muCT parameters except for degree of anisotropy (DA). Fast wave amplitude (FWA) is directly correlated with bone surface and total volume ratio (BS/TV) and trabecular separation (Tb Sp), and inversely correlated with trabecular number (Tb N). Because muCT parameters were strictly correlated to BMD and Young's modulus data, partial correlation analysis was performed between SOS, FWA, and structural and elastic data in order to eliminate the effect of density. SOS was significantly correlated to bone volume and total volume ratio (BV/TV), BS/TV, and Young's modulus, and FWA was significantly correlated to Tb Sp only. These results show that SOS is strongly influenced by volumetric mineral bone density and elastic modulus of the specimen, and FWA is mainly affected by trabecular separation independently on density. Therefore, SOS and FWA are able to provide different and complementary information, at least on trabecular bone samples.

The clinical use of quantitative ultrasound (QUS) in the detection and management of osteoporosis

For the detection and management of osteoporosis and osteoporosis-related fractures, quantitative ultrasound (QUS) is emerging as a relatively low-cost and readily accessible alternative to dual-energy X-ray absorptiometry (DXA) measurement of bone mineral density (BMD) in certain circumstances. The following is a brief, but thorough review of the existing literature with respect to the use of QUS in 6 settings: 1) assessing fragility fracture risk; 2) diagnosing osteoporosis; 3) initiating osteoporosis treatment; 4) monitoring osteoporosis treatment; 5) osteoporosis case finding; and 6) quality assurance and control. Many QUS devices exist that are quite different with respect to the parameters they measure and the strength of empirical evidence supporting their use. In general, heel QUS appears to be most tested and most effective. Overall, some, but not all, heel QUS devices are effective assessing fracture risk in some, but not all, populations, the evidence being strongest for Caucasian females over 55 years old. Otherwise, the evidence is fair with respect to certain devices allowing for the accurate diagnosis of likelihood of osteoporosis, and generally fair to poor in terms of QUS use when initiating or monitoring osteoporosis treatment. A reasonable protocol is proposed herein for case-finding purposes, which relies on a combined assessment of clinical risk factors (CR.F) and heel QUS. Finally, several recommendations are made for quality assurance and control.

Quantitative ultrasound methods to assess bone mineral status in children: technical characteristics, performance, and clinical application

Measurement of bone mineral status may be a useful tool in identifying the children who could be exposed to an increased risk of osteoporosis in adulthood. Dual energy x-ray absorptiometry and peripheral quantitative computed tomography may be used to this purpose, but the exposure to ionizing radiation is a limiting factor for preventive studies in large populations of children. In the last years, quantitative ultrasound (QUS) methods have been developed to assess bone mineral status in some peripheral skeletal sites such as calcaneus, phalanges of the hand, and tibia. QUS techniques are safe, easy to use, radiation-free, and devices are portable, so that they are particularly indicated to assess bone mineral status in children. This review will concentrate on the main methodological principles of ultrasounds and the QUS variables derived from their application to bone tissue, technical differences and performance of QUS methods, factors influencing QUS measurements, normative data and results obtained in children with disturbances of growth or affected by disorders of bone and mineral metabolism, including the assessment of fracture risk, and comparison among QUS, dual energy x-ray absorptiometry, and peripheral quantitative computed tomography methods.

Ultrasonic guided waves in bone

Recent progress in quantitative ultrasound (QUS) has shown increasing interest toward measuring long bones by ultrasonic guided waves. This technology is widely used in the field of nondestructive testing and evaluation of different waveguide structures. Cortical bone provides such an elastic waveguide and its ability to sustain loading and resist fractures is known to be related to its mechanical properties at different length scales. Because guided waves could yield diverse characterizations of the bone's mechanical properties at the macroscopic level, the method of guided waves has a strong potential over the standardized bone densitometry as a tool for bone assessment. Despite this, development of guided wave methods is challenging, e.g., due to interferences and multiparametric inversion problems. This paper discusses the promises and challenges related to bone characterization by ultrasonic guided waves.

Instrumentation for in vivo ultrasonic characterization of bone strength

Although it has been more than 20 years since the first recorded use of a quantitative ultrasound (QUS) technology to predict bone fragility, the field has not yet reached its maturity. QUS has the potential to predict fracture risk in several clinical circumstances and has the advantages of being nonionizing, inexpensive, portable, highly acceptable to patients, and repeatable. However, the wide dissemination of QUS in clinical practice is still limited and suffering from the absence of clinical consensus on how to integrate QUS technologies in bone densitometry armamentarium. Several critical issues need to be addressed to develop the role of QUS within rheumatology. These include issues of technologies adapted to measure the central skeleton, data acquisition, and signal processing procedures to reveal bone properties beyond bone mineral quantity and elucidation of the complex interaction between ultrasound and bone structure. This article reviews the state-of-the art in technological developments applied to assess bone strength in vivo. We describe generic measurement and signal processing methods implemented in clinical ultrasound devices, the devices and their practical use, and performance measures. The article also points out the present limitations, especially those related to the absence of standardization, and the lack of comprehensive theoretical models. We conclude with suggestions of future lines and trends in technology challenges and research areas such as new acquisition modes, advanced signal processing techniques, and modelization.

Bone alterations in children and young adults with renal transplant assessed by phalangeal quantitative ultrasound

BACKGROUND

Bone alterations in young renal transplant recipients were investigated in several studies with conflicting results. Quantitative ultrasound of the phalanges is a recently developed noninvasive procedure to assess skeletal status.

STUDY DESIGN

Cross-sectional study at a single transplant center with values compared with previously studied healthy controls.

SETTINGS & PARTICIPANTS

40 children and young adult recipients of renal grafts (15 females, 25 males; age, 20.0 +/- 8.4 years) studied 7.1 +/- 3.8 years after kidney transplantation.

PREDICTOR

Clinical, biochemical, and therapeutic features, including calcium, phosphate, and intact parathormone levels; and cumulative dosages of glucocorticoids and cyclosporine administered since transplantation.

OUTCOME & MEASUREMENT

Phalangeal quantitative ultrasound, including amplitude-dependent speed of sound (AD-SoS) and bone transmission time (BTT), mainly dependent on mineral density and cortical thickness, respectively. Age- and sex-matched healthy controls were used to provide age-related z scores; sex- and height-matched healthy subjects, to provide z scores related to statural age.

RESULTS

Mean z scores of AD-SoS and BTT were -0.05 +/- 1.59 and -0.54 +/- 1.17, respectively (P > 0.05 and P < 0.001, respectively). Multivariate analysis showed that AD-SoS z score was associated significantly with body mass index, intact parathormone level, cumulative glucocorticoids administered in the first posttransplantation year, and cyclosporine administered since transplantation (model r(2) = 0.79; P < 0.001); BTT z score was associated significantly with glucocorticoid dosage in the first posttransplantation year and age (model r(2) = 0.55; P < 0.001).

LIMITATIONS

Absence of other measures of bone structure and longitudinal measures and comparison to a noncurrent control group.

CONCLUSIONS

Children and young adults may have decreased cortical thickness with maintained overall mineral density after renal transplantation. The findings of phalangeal quantitative ultrasound parallel observations using other imaging techniques. Phalangeal quantitative ultrasound may be a useful method to assess bone alternations after renal transplantation.

QUS in monitoring raloxifene and estrogen-progestogens: a 4-year longitudinal study

The aim of the study is to evaluate the effectiveness of phalangeal quantitative ultrasound (QUS) in monitoring the treatment with raloxifene or estrogen-progestogens in postmenopausal women attending an Italian Menopause Centre. Caucasian women (n = 268) were enrolled in the study and underwent annual check-ups between October 1998 and October 2004. All were measured with the IGEA DBM Sonic Bone Profiler (BP) at the startup of treatment and in the following years. Three groups were identified: subjects not receiving treatment (n = 144), subjects treated with raloxifene (n = 53) and subjects treated with estrogen-progestogens (n = 71). The three analyzed groups were similar for age, weight and menopausal age. A significant decrease in amplitude-dependent speed of sound (AD-SoS) and Ultrasound Bone Profile Index (UBPI; p < 0.05) was observed in the nontreated group, whereas a positive effect in treated groups could be evidenced in the follow-up. In particular, a significant positive effect (p < 0.05) on AD-SoS corrected for age in the group treated with raloxifene has been observed, whereas in the group treated with estrogen-progestogens a nonsignificant positive effect on AD-SoS corrected for age was observed. The absolute AD-SoS value was maintained over the years of follow-up. The UBPI data show a slowing down of the bone loss in the treated groups, especially in the raloxifene group, in contrast with the significant decrease in the nontreated group. The result of this study shows the DBM Sonic Bone Profiler is an efficient device to monitor the effects of treatment, not only in the strict control settings of clinical trials, but also in clinical practice.