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Biomedical subjects

D Hans

Publications and source records attributed to D Hans.

At least 37 records · Page 2Linked to original sources
PubMed2001

Quantitative ultrasound of the tibia depends on both cortical density and thickness.

This study investigated whether tibial speed of sound (SOS; SoundScan 2000, Myriad Ultrasound Systems, Israel) reflects not only bone mineral density (BMD) but also tibial cortical thickness, as assessed by dual-energy X-ray absorptiometry (DXA) and Quantitative CT (QCT) at a site-matched location. The secondary focus of the study was how tibial SOS compares with BMD at the spine and the hip, the most widely used locations for densitometry. Twenty-two young normal (N) and 23 postmenopausal women with spinal fractures (Fx) (mean (SD) age 35 (8) and 70 (5) years) underwent quantitative ultrasound (QUS) SOS measurement at the left tibial midshaft. From site-matched QCT scans (three 3-mm slices spaced along the QUS measurement region), BMD and cortical thickness were computed (QCT-cBMD, QCT-cTh). The cortex in the CT images was then subdivided into three concentric and equally spaced bands, and QCT-cBMD was computed separately for each band. DXA was performed at the mid-tibia (TIB BMD), at the spine (SPINE BMD) and the hip (total hip, HIP BMD). Correlation coefficients between parameters were determined with least-square linear fits. Intergroup differences were assessed by analysis of covariance, whose r2 value reflects the percentage variation in the data explained by group assignment. SOS correlated significantly with site-matched parameters (QCT-cBMD, OCT-cTh and TIB BMD, all r = 0.6, p < 0.001), SPINE BMD and HIP BMD (both r = 0.5, p < 0.001). Multiple regression with both QCT-cBMD and QCT-cTh against SOS yielded r = 0.7 with both parameters contributing significantly. For the cortex band subdivision, SOS correlated better with QCT-cBMD in the outermost band of the cortex (r = 0.67) than with the more central bands (r = 0.59 and r = 0.53). Group assignment could best explain SPINE BMD (r2 = 0.62) and HIP BMD (r2 = 0.51). SOS was comparable to TIB BMD (r2 = 0.3 vs. r2 = 0.35).: Our findings suggest that the tibial SOS measurement depends on both the thickness and density of the tibia, but is more strongly influenced by the density of the cortex near the surface than by its interior parts. The power of tibial ultrasound to discriminate between normal and fracture patients was less than that of spinal and femoral DXA BMD and comparable to site-matched DXA BMD.

Absorptiometry, Photon↗
PubMed2001

Age-related differences in fat-free mass, skeletal muscle, body cell mass and fat mass between 18 and 94 years.

OBJECTIVE: To determine (1) lean and fat body compartments, reflected by fat-free mass (FFM), appendicular skeletal muscle mass (ASMM), body cell mass (BCM), total body potassium (TBK), fat mass and percentage fat mass, and their differences between age groups in healthy, physically active subjects from 18 to 94 y of age; and (2) if the rate of decrease in any one of the parameters by age might be accelerated compared to others. METHODS: A total of 433 healthy ambulatory Caucasians (253 men and 180 women) aged 18--94 y were measured by dual-energy X-ray absorptiometry (DXA) and whole body scintillation counter (TBK counter) using a large sodium iodide crystal (203 mm diameter). RESULTS: The ASMM change (-16.4 and -12.3% in men and women, respectively) in >75 y-old compared to 18 to 34-y-old subjects was greater than the FFM change (-11.8 and -9.7% in men and women, respectively) and this suggests that skeletal muscle mass decrease in older subjects was proportionally greater than non-skeletal muscle mass. BCM (-25.1 and -23.2% in men and women, respectively) and TBK differences were greater than the differences in FFM or ASMM suggesting altered composition of FFM in older subjects. Women had lower peak FFM, ASMM, BCM and TBK than men. CONCLUSIONS: The decline in FFM, ASMM, BCM and TBK is accelerated in men and women after 60 y of age and FFM, ASMM, BCM and TBK are significantly lower than in younger subjects. Fat mass continued to increase until around 75 y.

Absorptiometry, Photon↗
PubMed2001

Total body mass, fat mass, fat-free mass, and skeletal muscle in older people: cross-sectional differences in 60-year-old persons.

OBJECTIVES: To evaluate body composition parameters, including fat-free mass (FFM), appendicular skeletal muscle mass (ASMM), relative skeletal muscle mass (RSM) index, body cell mass (BCM), BCM index, total body potassium (TBK), fat mass, percentage fat mass (FM), and their differences between age groups and to evaluate the frequency of sarcopenia in healthy older subjects DESIGN: Cross-sectional, nonrandomized study. SETTING: Outpatient clinic. PARTICIPANTS: Ninety-one healthy men and 100 healthy women age 60 and older. MEASUREMENTS: FFM, ASMM, FM, and percentage fat mass by whole-body dual-energy x-ray absorptiometry; TBK, BCM, and TBK/FFM ratio by whole body potassium-40 counter. RESULTS: All lean body mass parameters were significantly (P <.05) lower in subjects age 80 and older than in those age 70 to 79, except ASMM in women. Mean FFM was 4.2 kg (7.3%) lower in men age 80 and older than in those younger than 70 and 2.9 kg (6.8%) lower in women age 80 and older than in those younger than 70. The skeletal muscle mass, reflected by ASMM, decreased more than FFM. This suggests that nonskeletal muscle mass is proportionally preserved during aging. Forty-five percent of men and 30% of women were sarcopenic by definition of BCM index and 11.0% of men and women by definition of RSM index. CONCLUSIONS: Significant age-related differences exist in body composition of older men and women between age 60 and 95. The greater decrease in TBK and BCM than the decrease in FFM and skeletal muscle mass suggests changing composition of FFM with age. Lack of agreement between two independent sarcopenia indexes suggests that further refinement in the definition of a sarcopenia index is necessary.

Absorptiometry, Photon↗
PubMed2001

(133)Xe SPECT cerebral blood flow study in a healthy population: determination of T-scores.

UNLABELLED: Dementia is becoming a major health problem as the population of the Northern Hemisphere ages. Early differential diagnosis between normal cognitive decline and dementia is particularly difficult. If psychometric evaluation can contribute to the diagnosis, quantitative cerebral functional imaging would play an important role. We therefore proposed, first, to constitute a normative dataset that could later be used to identify subjects at risk for neurodegenerative processes and, second, to describe the risk of abnormal global cerebral blood flow (gCBF) by defining categories based on the standardized cutoff scores of a young, healthy population (T-score). METHODS: Of a total of 203 healthy volunteers, 187 were included in the protocol, which included evaluation of medical history, neurologic and neuropsychologic status, and body composition; analysis of blood; and measurement of gCBF by means of (133)Xe SPECT. RESULTS: With ANOVA analysis using age and sex as between-subject factors and gCBF as a within-subject factor, a significantly higher gCBF was found in women than in men. In addition, a linear reduction as a function of age was observed for both sexes (-0.3%/y). T-score was determined for the 18- to 28-y-old age group, for whom gCBF was found to be 46.7 +/- 5.1 mL/min/100 g tissue in men and 49.0 +/- 5.0 mL/min/100 g tissue in women. The age-dependent decrease could thus be expressed in T-scores and, in the 29- to 38-y-old, 39- to 48-y-old, and >48-y-old age groups, averaged -0.63, -1.29, and -1.92, respectively, in men and -0.63, -0.83, and-2.40, respectively, in women. Cognitive performance, body composition, and blood analysis revealed the expected significant effects from sex and age. CONCLUSION: The large-scale reference database of gCBF measurements constituted from a healthy, well-controlled population enabled age and sex stratification, which showed significant differences between the sexes and a significant decline as a function of age. T-scores were determined and warrant further studies on the prospective identification of early dementia by (133)Xe SPECT in elderly individuals.

Adolescent↗
PubMed2000

Deaths from breast cancer: tackling multidimensionality and non-linearity by correspondence analysis.

AIM: We investigated the use of non-linear, multidimensional factor analysis for the study of observational data on death from breast cancer. These data were obtained in the context of a clinical practice and not in a clinical trial. We looked into the correlations between patient characteristics and time of death and/or disease-free interval. PATIENTS AND METHODS: We first analyzed the characteristics of a population of patients that had died from breast cancer (n = 295), then of a population including patients still alive 7 years after surgery (n = 344). We used correspondence analysis (CA) which is based on chi(2)-metrics, does not assume linear relationships, and provides graphic overviews. RESULTS: The CA mapped variables (clinical stage, histoprognostic grade, node status, receptor positivity) in a way that fits in well with available knowledge on their importance as prognostic factors. We observed, however, that death occurred during three main periods (1-3, 4-7, < OR = 8 years after surgery) defined by different mixes of variables as if the disease progressed by stage rather than continuously. The CA distinguished long-term survivors (>7 years) from patients who died 8-10 years after surgery. Long-term survivors tended to be node-negative; those who died at 8-10 years tended to be the youngest patients (under 40). CONCLUSIONS: Because correspondence analysis combines the advantages of multidimensional and non-linear methods, it is a valuable exploratory tool for describing multiple correlations within a population before attempting to establish statistical significance of selected variables by more classic methods.

Adult↗
PubMed2000

Comparison of six calcaneal quantitative ultrasound devices: precision and hip fracture discrimination.

Quantitative ultrasound (QUS) is now accepted as a useful tool in the management of osteoporosis. There are a variety of QUS devices clinically available with a number of differences among them, including their coupling methods, parameter calculation algorithms and sites of measurement. This study evaluated the abilities of six calcaneal QUS devices to discriminate between normal and hip-fractured subjects compared with the established method of dual-energy X-ray absorptiometry (DXA). The short-term and mid-term precisions of these devices were also determined. Thirty-five women (mean age 74.5+/-7.9 years) who had sustained a hip fracture within the past 3 years, and 35 age-matched controls (75.8+/-5.6 years) were recruited. Ultrasound measurements were acquired using six ultrasound devices: three gel-coupled and three water-coupled devices. Bone mineral density was measured at the hip using DXA. Discrimination of fracture patients versus controls was assessed using logistic regression analysis (expressed as age- and BMI-adjusted odds ratios per standard deviation decrease with 95% confidence interval) and receiver operating characteristics (ROC) curve analysis. Measurement precision was standardized to the biological range (sCV). The sCV ranged from 3.14% to 5.5% for speed of sound (SOS) and from 2.45% to 6.01% for broadband ultrasound attenuation (BUA). The standardized medium-term precision ranged from 4.33% to 8.43% for SOS and from 2.77% to 6.91% for BUA. The pairwise Pearson correlation coefficients between different devices was highly significant (SOS, r = 0.79-0.93; BUA, r = 0.71-0.92). QUS variables correlated weakly, though significantly, with femoral BMD (SOS, r = 0.30-0.55; BUA, r = 0.35-0.61). The absolute BUA and SOS values varied among devices. The gel-coupled devices generally had a higher SOS than water-coupled devices. Bone mineral density (BMD) and BUA were weakly correlated with weight (r = 0.48-0.57 for BMD and r = 0.18-0.54 for BUA), whereas SOS was independent of weight. All the QUS devices gave similar, statistically significant hip fracture discrimination for both SOS and BUA measures. The odds ratios for SOS (2.1-2.8) and BUA (2.4-3.4) were comparable to those for femoral BMD (2.6-3.5), as were the area under the curve (SOS, 0.65-0.71; BUA, 0.62-0.71; BMD, 0.65-0.74) from ROC analysis. Within the limitation of the sample size all devices show similar diagnostic sensitivity.

Absorptiometry, Photon↗
PubMed2000

Assessment of a new quantitative ultrasound calcaneus measurement: precision and discrimination of hip fractures in elderly women compared with dual X-ray absorptiometry.

The incidence of osteoporotic hip fracture increases in postmenopausal women with low hip bone mineral density (BMD). Dual X-ray absorptiometry (DXA) is the most commonly used technique for the assessment of bone status and provides good measurement precision. However, DXA affords little information about bone architecture. Quantitative ultrasound (QUS) systems have been developed to evaluate bone status for assessment of fracture risk. Our study was designed to assess a new QUS system from Hologic, the Sahara; to compare it with a previous model, the Walker-Sonix UBA 575+; and to investigate whether it is able to discriminate between women with and without fracture. Using both ultrasound devices, the measurements were performed at the heels of 33 postmenopausal women who had recently sustained hip fracture. A control group of 35 age-matched postmenopausal women was recruited for comparison. The total, neck and trochanter femoral BMD values were assessed using DXA for both groups. QUS and DXA measurements were significantly lower in fractured patients (p < 0.005) than in the control group. The short-term, mid-term and standardized short-term precisions were used to evaluate the reproducibility of the two QUS systems. The Sahara showed a better standardized coefficient of variation for broadband ultrasound attenuation (BUA) than did the UBA 575+ (p < 0.001). The correlation of BUA and speed of sound (SOS) between the two QUS devices was highly significant, with an r value of 0.92 for BUA and 0.91 for SOS. However, the correlation between DXA and ultrasound parameters ranged from 0.28 to 0.44. We found that ultrasound measurements at the heel were significant discriminators of hip fractures with odds ratios (OR) ranging from 2.7 to 3.2. Even after adjusting the logistic regressions for total, neck or trochanter femoral BMD, QUS variables were still significant independent discriminators of hip fracture. The areas under the ROC curves of each ultrasound parameter ranged from 0.75 to 0.78, and compared very well with femoral neck BMD (p > 0.05). In conclusion, our study indicated that the calcaneal QUS variables, as measured by the Sahara system can discriminate hip fracture patients equally as well as hip DXA.

Absorptiometry, Photon↗
PubMed2000

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

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

Absorptiometry, Photon↗
PubMed2000

Prediction of bone strength of distal forearm using radius bone mineral density and phalangeal speed of sound.

This investigation compares quantitative ultrasound (QUS) measurement of the phalanges with peripheral quantitative computed tomography (pQCT) and dual X-ray absorptiometry (DXA) measurement of the forearm, to estimate the strength of the distal radius in 13 cadaveric forearms. The cadavers were scanned at the distal radius by pQCT and DXA for bone mineral density (BMD) and at the approximate phalanges by QUS for speed of sound (SOS). The distal radii were subjected to a simulated Colles fracture produced with a materials testing machine. The load at which the distal radius was fractured was considered as a representation of bone strength. The bone strength correlated significantly with SOS at different phalanges (r = 0.63-0.72), BMD at different regions of interest by DXA (r = 0.67-0.75), and cortical BMD at different sites by pQCT (r = 0.61-0.67). Standard stepwise regression analysis showed that adding phalangeal SOS into forearm densitometric variables significantly enhanced the statistical power for prediction of the strength of the distal radius. Our results suggest that, for assessment of site-specific distal forearm strength, QUS measurement of the phalanges is comparable to forearm densitometry. Phalangeal QUS may add clinical value if distal forearm strength has a high priority.

Aged↗
PubMed2000

Advanced imaging of the macrostructure and microstructure of bone.

Noninvasive and/or nondestructive techniques are capable of providing more macro- or microstructural information about bone than standard bone densitometry. Although the latter provides important information about osteoporotic fracture risk, numerous studies indicate that bone strength is only partially explained by bone mineral density. Quantitative assessment of macro- and microstructural features may improve our ability to estimate bone strength. The methods available for quantitatively assessing macrostructure include (besides conventional radiographs) quantitative computed tomography (QCT) and volumetric quantitative computed tomography (vQCT). Methods for assessing microstructure of trabecular bone noninvasively and/or nondestructively include high-resolution computed tomography (hrCT), micro-computed tomography (muCT), high-resolution magnetic resonance (hrMR), and micromagnetic resonance (muMR). vQCT, hrCT and hrMR are generally applicable in vivo; muCT and muMR are principally applicable in vitro. Although considerable progress has been made in the noninvasive and/or nondestructive imaging of the macro- and microstructure of bone, considerable challenges and dilemmas remain. From a technical perspective, the balance between spatial resolution versus sampling size, or between signal-to-noise versus radiation dose or acquisition time, needs further consideration, as do the trade-offs between the complexity and expense of equipment and the availability and accessibility of the methods. The relative merits of in vitro imaging and its ultrahigh resolution but invasiveness versus those of in vivo imaging and its modest resolution but noninvasiveness also deserve careful attention. From a clinical perspective, the challenges for bone imaging include balancing the relative advantages of simple bone densitometry against the more complex architectural features of bone or, similarly, the deeper research requirements against the broader clinical needs. The considerable potential biological differences between the peripheral appendicular skeleton and the central axial skeleton have to be addressed further. Finally, the relative merits of these sophisticated imaging techniques have to be weighed with respect to their applications as diagnostic procedures requiring high accuracy or reliability on one hand and their monitoring applications requiring high precision or reproducibility on the other.

Animals↗
PubMed2000

Comparison of an imaging heel quantitative ultrasound device (DTU-one) with densitometric and ultrasonic measurements.

The purpose of this study was to evaluate a new imaging ultrasound scanner for the heel, the DTU-one (Osteometer MediTech, Denmark), by comparing quantitative ultrasound (QUS) results with bone mineral density (BMD) of the heel and femur from dual X-ray absorptiometry (DXA), and by comparing the DTU-one with another QUS device, the UBA 575+. The regions of interest in the DXA heel scan were matched with the regions evaluated by the two QUS devices. 134 healthy and 16 osteoporotic women aged 30-84 years old were enrolled in the study. In vivo short-term precision of the DTU-one for broadband ultrasound attenuation (BUA) and speed of sound (SOS) was 2.9% and 0.1%, respectively, and long-term precision was 3.8% and 0.2%, respectively. Highest correlations (r) between QUS and BMD measurements were achieved when comparing DTU-one results with BMD in matched regions of the DXA heel scan. Correlation coefficients (r) were 0.81 for BUA and SOS. Highest correlations with the UBA 575+ were 0.68 and 0.72, respectively. The comparison of BMD in different femoral sites with BUA and SOS (DTU-one) varied from 0.62 to 0.69 when including the entire study population. The correlation between BMD values within different sites of the femur tended to be higher (from r = 0.81 to 0.93). When comparing BUA with BUA and SOS with SOS on the two QUS devices, the absolute QUS values differed significantly. However, correlations were relatively high, with 0.76 for BUA and 0.82 for SOS. In conclusion, the results of the new quantitative ultrasound device, the DTU-one, are highly correlated (r = 0.8) with results obtained using the UBA 575+ and with BMD in the heel. The precision of the DTU-one is comparable to other QUS devices for BUA and is high for SOS.

Absorptiometry, Photon↗
PubMed2000

Phalangeal osteosonogrammetry study: age-related changes, diagnostic sensitivity, and discrimination power. The Phalangeal Osteosonogrammetry Study Group.

Phalangeal osteosonogrammetry was introduced as a method for bone tissue investigation in 1992. It is based on the measure of the velocity of ultrasound (amplitude-dependent speed of sound [AD-SoS]) and on the interpretation of the characteristics of the ultrasound signal. In this study we have collected a database of 10,115 subjects to evaluate the performance of AD-SoS and to develop a parameter that is able to quantify the signal characteristics: ultrasound bone profile index (UBPI). The database only includes females of which 4.5% had documented vertebral osteoporotic fractures, 16% lumbar spine dual X-ray absorptiometry (DXA), and 6% hip DXA. The analysis of the ultrasound signal has shown that with aging the UBPI, first wave amplitude (FWA), and signal dynamics (SDy) follow a trend that is different from the one observed for AD-SoS; that is, there is no increase during childhood. In the whole population, the risk of fracture per SD decrease for AD-SOS was odds ratio (OR) 1.71 (CI, 1.58-1.84). The AD-SoS in fractured subjects was significantly lower than in a group of age-matched nonfractured subjects (p < 0.0001). In a small cohort of hip-fractured patients UBPI proved to be lower than in a control age-matched group (p < 0.0001). When the World Health Organization (WHO) working group criteria were applied to this population to identify the T score value for osteoporosis, for AD-SoS we found a T score of -3.2 and for UBPI we found a T score of -3.14. Sixty-six percent of vertebral fractures were below the AD-SoS -3.2 T score and 62% were below UBPI -3.14. We observed the highest incidence of fractures (63.6%) among subjects with AD-SoS who had both DXA T score values below the threshold. We conclude from this study that ultrasound investigation at the hand phalanges is a valid methodology for osteoporosis assessment. It has been possible to quantify signal changes by means of UBPI, a parameter that will improve the possibility of investigating bone structure.

Adult↗
PubMed2000

A new method for quantitative ultrasound measurements at multiple skeletal sites: first results of precision and fracture discrimination.

We investigated a new multisite quantitative ultrasound device that measures the acoustic velocity in axial transmission mode along the cortex. Using a prototype of the Omnisense (Sunlight Ultrasound Technologies, Rehovot, Israel), we tested the performance of this instrument at four sites of the skeleton: radius, ulna, metacarpal, and phalanx. Intraobserver (interobserver) precision errors ranged from 0.2% to 0.3% (0.3% to 0.7%) for triplicate measurements with repositioning. Fracture discrimination was tested by comparing a group of 34 women who had previously suffered a fracture of the hip, spine, ankle, or forearm to a group of 28 healthy women who had not suffered a fracture. Age-adjusted standardized odds ratios ranged from 1.6 to 4.5. Except for the ulna the sites showed a significant fracture discrimination (p < 0.01). The areas under the receiver operating curves (ROC) curves were from 0.88 to 0.89 for radius, metacarpal, and phalanx. A combination of the results from the three sites showed a significant increase of the ROC area to 0.95 (p < 0. 05). Our results show promising performance of this new device. The ability to measure a large variety of sites and the potential to combine these measurements are promising with regard to optimizing fracture risk assessment.

Aged↗
PubMed1999

Evaluation of finger ultrasound in the assessment of bone status with application of rheumatoid arthritis.

Osteoporosis associated with active rheumatoid arthritis (RA) has been demonstrated in both the axial and peripheral skeleton, especially the periarticular regions more directly affected by the disease. Quantitative ultrasound (QUS) is a recently accepted tool for the assessment of bone status, and therefore could be used to monitor bone changes in RA patients. In a cross-sectional study we measured ultrasound velocity (Ad-SOS) through the proximal phalanges in three groups of female subjects. These included: 51 patients with rheumatoid arthritis (group 1), 44 general practitioner (GP)-referred patients for osteopenia (group 2) and 52 young healthy volunteers (group 3). For groups 1 and 2 bone mineral density (BMD) of the lumbar spine and proximal femur were also measured. For the RA patients BMD of the hand, measurement of hand function (HAQ and grip strength) and disease activity (ESR and CRP) were also assessed. The precision of long-term Ad-SOS measurements on volunteers gave a root mean square coefficient of variation (CV) of 0.7% and standardized CV of 3.6%. No statistically significant effect of dominance was observed in the measured Ad-SOS between the dominant and non-dominant hand (r = 0.96, p < 0.001). Ad-SOS was found to be significantly different in the three groups (p < 0.0001). Ad-SOS was highly dependent on age (r = -0.67), with a gradual reduction (-5.2 m/s per year) after the age of 30 years for female patients in both group 1 and group 2. Ad-SOS was significantly correlated with lumbar spine, femoral neck and hand BMD, with correlation coefficients of 0.49, 0.51 and 0.72 respectively for RA patients. Finger ultrasound was moderately correlated with measures of hand function, with coefficients of 0.37 and 0.39 for HAQ and grip strength respectively. Hand BMD also correlated to the same power with these parameters. Neither finger ultrasound nor BMD was significantly correlated with ESR and CRP (measures of disease activity). We have demonstrated that bone status can be assessed quickly and cheaply using a portable QUS device. Ad-SOS relates to the measure of hand function in RA patients. Longitudinal studies are required to determine the usefulness of finger ultrasound for monitoring disease progression or the effect of treatment in RA.

Adult↗
PubMed1999

Separate and combined value of bone mass and gait speed measurements in screening for hip fracture risk: results from the EPIDOS study. Epidémiologie de l'Ostéoporose.

Based on data from the EPIDOS prospective study, we have shown that femoral bone mineral density (BMD), calcaneal ultrasound measurements and fall-related factors are significant predictors of the risk of hip fracture. The goal of the present investigation, in the same cohort of elderly women, was (1) to assess and compare the value of femoral BMD, calcaneal broadband ultrasound attenuation (BUA), gait speed and age for identifying elderly women at high risk of hip fracture and (2) to determine whether combining two or more of these measurements would improve predictive ability over single measures. A total of 5895 elderly women had baseline measurements of femoral neck BMD by dual-energy X-ray absorptiometry, calcaneal BUA and gait speed. During an average of 33 months of follow-up, 170 women suffered a hip fracture. We compared the sensitivity and specificity of single and combined measures for three specific cutoff levels to define high risk, i.e., the median, the top quartile and the top decile of risk. We found that femoral BMD, calcaneal BUA, gait speed and age have approximatively the same discriminant value to identify women at high risk of hip fracture even though certain measures and combinations of measures have a significantly higher sensitivity for certain cutoff levels. The sensitivity of the available screening tools is low, even when they are combined: to obtain a sensitivity of about 80%, approximately 50% of the population must be considered to be at high risk.

Aged↗
PubMed1999

Ultrasound velocity of trabecular cubes reflects mainly bone density and elasticity.

Studies have indicated that quantitative ultrasound (QUS) variables may be influenced by the mechanical properties of bone which in turn are determined by bone's material and structural properties. However, from these studies it is unclear what role density, elasticity, and structure play in determining velocity. Eighteen defatted, 12-mm cubic trabecular bone specimens were cut from cadaveric specimens. Amplitude-dependent speed of sound (SOS) using a single point QUS system was assessed in three orthogonal axes. Magnetic resonance images were obtained, from which measures of apparent trabeuclar structure were derived. The specimens were nondestructively tested in compression along three orthogonal axes defined by the sides of the cubes. The elastic modulus (in the three directions) and the strength (in one direction) were determined. Trabecular BMD was measured by quantitative computed tomography. SOS varied significantly with direction of measurement, with the highest value in the axial direction (axial:1715 m/s, sagittal: 1662 m/second, and coronal: 1676 m/s). SOS of each of the three axes was generally associated with the various mechanical (r = 0.30-0.87), density (r = 0.81-0.93), and bone structural variables (0.3-0.8). However, after adjusting the SOS correlations by density, only the correlation with elasticity remained significant in the coronal direction. BMD alone explained 88-93% of variance in SOS whereas in the multivariate model, BMD plus elasticity and/or anisotropic variables explained 96-98% of the variance in SOS. Variability of SOS is explained mostly by density and to a small extent by elasticity or anisotropy. Since only 2-6% of the variance of the QUS measurement is not explained by density and elasticity, one could conclude that the remaining variance reflects other properties of bone or perhaps simply measurement error. Evidence that these other properties may be structure related is only found in the anisotropy of QUS parameter.

Adult↗