Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “DXA”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed2005

Comparison of dual X-ray absorptiometry (DXA), digital X-ray radiogrammetry (DXR), and conventional radiographs in the evaluation of osteoporosis and bone erosions in patients with rheumatoid arthritis.

OBJECTIVE: To compare the relationship between bone mineral density (BMD) in the metacarpal bones and forearm measured by dual X-ray absorptiometry (DXA) and digital X-ray radiogrammetry (DXR) and radiological alterations in patients with early and established rheumatoid arthritis (RA). PATIENTS AND METHODS: In each of the three disease duration groups, 11 female RA patients were included. The patients were further divided into two groups according to bone erosions. BMD in the metacarpals was evaluated by DXA and DXR. RESULTS: A significant relationship between DXA-BMD and DXR-BMD was observed. DXR-BMD and the individually combined cortical thickness (CT) of the metacarpo-phalangeal (MCP) joints were related to disease duration and erosions. Patients with erosive disease had lower values of age- and sex-adjusted BMD measured with DXA, but most significantly with DXR. CONCLUSION: DXR appears to be a more sensitive method than DXA in detecting early bone loss in patients with RA. The relationship of DXR-BMD to disease duration and bone damage indicates that the DXR method may be useful in the evaluation of disease activity and progression.

Absorptiometry, Photon↗
PubMed2000

DXA body composition studies are not affected by extracellular water measurements using stable sodium bromide dilution.

Body composition studies using dual energy x-ray absorptiometry (DXA) are being increasingly reported in the literature. When DXA body composition measurements are combined with body water studies, stable bromide is often administered to measure extracellular water. Bromine attenuates x-rays significantly more than soft tissue and so could affect DXA body composition analysis. DXA scans were performed on 26 adults (12 F, 14 M) before and after the intravenous injection of 3 g sodium bromide (NaBr). No significant differences were noted pre- and post-NaBr infusion for whole-body fat mass, fat-free soft tissue mass and bone mineral content. These findings were supported by a simple mathematical analysis of the likely effect of the sodium bromide infusion. This showed that when 3 g NaBr was introduced into the body, the effect on fat mass estimates was expected to be marginally less than the precision of the DXA technique.

Absorptiometry, Photon↗
PubMed2004

The significant effects of bone structure on inherent patient-specific DXA in vivo bone mineral density measurement inaccuracies.

An extended analytic exposition is developed of the effects bone structure has on the form and extent of systematic inaccuracies in planar dual-energy x-ray absorptiometry (DXA) in vivo bone mineral density (BMD) measurements. Explicit expressions for absolute and percentage BMD inaccuracies are derived and criteria governing these BMD inaccuracies delineated. It is shown that the effect of bone structure is to introduce a scale factor which modulates the sizable and unavoidable DXA in vivo/in situ BMD inaccuracies that arise directly from patient-specific anthropometric and x-ray absorptiometric disparities among the several soft tissues present within the scan region of interest of any given bone site (i.e., lean muscle tissue, interposed and admixed fat, and red/yellow marrow combinations). Different magnitudes and patterns of BMD inaccuracies are shown to pertain for bone structures that are (i) essentially wholly trabecular, (ii) wholly cortical, and (iii) those containing both cortical and trabecular bone. Over the range of soft tissue anthropometrics typical of adult patients, the overall percentage inaccuracies in DXA-measured BMD are shown to be quite sizable and to vary considerably for different bone structures. For a typical lumbar vertebral bone site, BMD inaccuracies are found to be as large as approximately 25% for normal patients, to exceed approximately 35% for osteopenics, and to approach 50% for osteoporotic individuals. For bone sites with non-negligible cortical surrounds of trabecular structures (e.g., distal radius, some segments of proximal femur, etc.), it is shown that BMD percentage inaccuracies range up to approximately 20% for normal, approximately 25% osteopenic, and approximately 35% for osteoporotic patients. The BMD % inaccuracies associated with wholly cortical bone (trabecular-free) sites (e.g., mid-shaft femur, mid-shaft radius, etc.) are comparatively small, being less than approximately 2%. Depending on bone structure, bone size and shape, and patient-specific intra- and extra-osseous soft tissue particulars of any given adult patient, DXA in vivo BMD measurements can be grossly inaccurate, and can severely under- or over-estimate the true value of BMD and mask or exaggerate true changes in BMD in ways not previously elucidated. It is concluded that in vivo DXA-measured and actual BMD cannot be considered to be synonymous, and clinical reliance upon the two being the same may readily conduce to seriously flawed and misleading diagnostic, prognostic, and prospective results.

Absorptiometry, Photon↗
PubMed2000

Evaluation of a new body composition phantom for quality control and cross-calibration of DXA devices.

This study evaluated a new body composition phantom and its use for quality control and cross-calibration of dual-energy X-ray absorptiometry (DXA) instruments for measurements of body composition. We imaged the variable composition phantom (Lunar, Madison, WI) on eight different DXA devices. Deviations of up to 7% fat were observed when we compared the percent fat values measured by the different devices with the nominal values provided by the manufacturer. Absolute precision error of percent fat measurements for the phantom ranged from 0.6 to 0.8%. The phantom's percent fat values were also compared with whole body composition measurements from 130 female and male volunteers. The phantom detected differences in percent fat values that were similar to those found by comparing in vivo measurements with values from different DXA scanner models from the same manufacturer. When comparing different models of scanners from different manufacturers, such as the Hologic QDR-4500 and the Lunar DPX-IQ, the phantom showed a different relationship than was seen for patients. Therefore, corrections or comparisons based on the phantom data alone would be incorrect. In conclusion, the Lunar variable composition phantom is capable of accurately measuring the fat calibration of DXA devices and may be suitable for cross-sectional cross-calibration between scanners from the same manufacturer; however, for comparison of DXA scanners from different manufacturers, in vivo cross-calibration is still the only accurate method. The phantom may be used in longitudinal quality control to verify an instrument's temporal stability.

Absorptiometry, Photon↗
PubMed2005

Long-term fracture prediction by DXA and QUS: a 10-year prospective study.

UNLABELLED: This study investigated the ability of DXA and QUS to predict fractures long term when measured around the time of the menopause. We found both DXA and QUS are able to predict both any fracture and "osteoporotic" fractures and that QUS can predict independently of BMD. INTRODUCTION: There are now many treatments available for prevention of osteoporotic fracture. To be cost-effective, we need to target those most at risk. This study examines the ability of DXA and QUS to predict fractures in an early postmenopausal population of women. MATERIALS AND METHODS: We prospectively measured 3883 women who had been randomly selected from a community-based register. At baseline, they were measured using DXA of spine and hip (Norland XR-26) and QUS of the heel (Walker Sonix UBA 575). Follow-up had a mean of 9.7 +/- 1.1 (SD) years. All incident fractures were identified and validated by examination of X-ray reports, and these were compared with those without fracture in a Cox-regression model to calculate hazard ratios (HRs). RESULTS: We found adjusted HRs for any fracture per 1 SD reduction in spine BMD to be 1.61 (1.42-1.83), whereas neck of femur BMD was 1.54 (1.34-1.75). Areas under the curve (AUC) for a receiver operator characteristic (ROC) analysis were 0.62 for spine BMD and 0.59 for neck BMD. In a subgroup where QUS was also measured, the HR for a 1 SD reduction in BMD was 1.69 (1.29-2.22) for spine BMD and 1.55 (1.17-2.06) for neck BMD. The HR for a 1 SD reduction in broadband ultrasound attenuation (BUA) was 1.53 (1.19-1.96), and 1.44 (1.12-1.86) when further adjusted for neck BMD. The AUCs were 0.63 for spine BMD, 0.59 for neck BMD, and 0.62 for BUA. When only osteoporotic fractures were examined, the HRs increased in all situations. BUA showed the highest HR of 2.25 (1.51-3.34), and when further adjusted for neck BMD was 2.12 (1.38-3.28). CONCLUSIONS: In conclusion, it may be possible to scan women around the time of the menopause to predict future fractures. It seems that, for "osteoporotic" fractures, BUA may be an improved predictor of fractures in comparison with DXA, because the relative risk is highest for BUA, and independent of BMD.

Absorptiometry, Photon↗
PubMed1998

A new perspective on the causal influence of soft tissue composition on DXA-measured in vivo bone mineral density.

An extensive series of quantitative simulation studies replicating ideal dual-energy X-ray absorptiometric (DXA) bone mineral density (BMD) measurements of typical and realistic in vivo lumbar vertebral and proximal femoral sites has been carried out to quantitatively assess the extent of inherent systematic inaccuracies in such measurements. The results for these bone sites indicate that BMD inaccuracies as high as 20% or more can be anticipated clinically, particularly in cases of osteopenic, osteoporotic, and elderly patients. It is found that the most important soft-tissue anthropometric determinants of the extent of bone site-specific systematic in vivo BMD inaccuracies reflected in DXA measurements are the ratio of the areal density of extraosseous fat to that of lean muscle tissue immediately surrounding the interrogated bone site and the specific yellow/red marrow mix within the scanned bone. As such, the present findings focus directly on the question of whether or not the strong, positive correlations and associations between soft tissue compositional parameters and DXA-measured in vivo BMD determined in a large number of previous clinical investigations are, in toto or in part, biologically causal. The present results are seen to be quantitatively and qualitatively in conformity with the many clinical studies that have found marked general decreases (increases) in measured BMD as body weight and/or body fat mass decreases (increases). It is concluded that the clinically observed correlations between DXA-measured BMD and these anthropometric parameters are artefacts of the systematic errors (inaccuracies) inherent in planar DXA methodology and are unlikely to be of biological genesis.

Absorptiometry, Photon↗
PubMed2003

Can novel clinical densitometric techniques replace or improve DXA in predicting bone strength in osteoporosis at the hip and other skeletal sites?

New peripheral techniques are now available for the diagnosis of osteoporosis, but their value in the clinical management of the disease remains controversial. This study tests the hypothesis that peripheral quantitative computed tomography (pQCT) at the distal radius and/or quantitative ultrasound (QUS) at the calcaneus can serve as replacement or improvement of current methodology (QCT and DXA) for predicting bone strength at the hip and other sites. In 126 human cadavers (age, 80.2 +/- 10.4 years), DXA of the femur, spine, and radius and pQCT of the radius were acquired with intact soft tissues. QCT (spine) and QUS (calcaneus) were performed ex situ in degassed specimens. Femoral failure loads were assessed in side impact and vertical loading. Failure loads of the thoracolumbar spine were determined at three levels in compression and those of the radius by simulating a fall. Site-specific DXA explained approximately 55% of the variability in femoral strength, whereas pQCT and QUS displayed a lower association (15-40%). QUS did not provide additional information on mechanical strength of the femur, spine, or radius. All techniques displayed similar capability in predicting a combined index of failure strength at these three sites, with only QUS exhibiting significantly lower associations than other methods. These experimental results suggest that clinical assessment of femoral fracture risk should preferably rely on femoral DXA, whereas DXA, QCT, and pQCT display similar capability of predicting a combined index of mechanical strength at the hip, spine, and radius.

Absorptiometry, Photon↗
PubMed1998

Radiation dose from DXA scanning to reproductive tissues of females.

The objective of this study was to use an anatomically arrayed whole-body phantom to measure radiation exposure to the ovaries and uterus during standard dual-energy Xray absorptiometry (DXA) scanning. DXA instrument manufacturers' published entrance skin exposure is about 3 mR (0.77 microC/kg), which is equivalent to the radiation exposure received during a transcontinental plane trip. Nonetheless, since DXA scanning is used more frequently with very young females, the need for pregnancy testing has become an issue that requires attention and formulation of research guidelines. We attached thermoluminescent dosimeters (TLDs) to anatomically arrayed balloon models for ovaries and the uterus, and placed these in the appropriate sites within a small human skeleton along with appropriate amounts of aqueous and fat soft tissue equivalents. Whole-body scanning with a Hologic QDR-2000W was performed 10 times with the pencil beam mode and, using separate TLD detectors, 10 times with the fan beam mode. Overall, the average exposures at skin entrance were 0.89 mR (0.23 microC/kg) with doses for the ovaries of 0.52 mrad (5.2 microgy) and 0.59 mrad (5.9 microgy) for the uterus. These doses are equivalent to 2 d of ambient background radiation in central Pennsylvania or 1 h of flying at 39,000 ft. Although different DXA models by Hologic and DXA instruments by other manufacturers will have different radiation outputs, we believe that these low radiation levels do not require pregnancy testing or questioning of whether the scan subject might be pregnant.

Journal Article↗
PubMed2002

Ultrasound of the phalanges is not related to a previous fracture. A comparison between ultrasound of the phalanges, calcaneus, and DXA of the spine and hip in 75-year-old women.

Recently, an ultrasound (US) device for measurement of amplitude-dependent speed of sound in four proximal phalanges of the hand (DBM Sonic 1200, IGEA, Carpi, Mo, Italy) has been introduced but has not been thoroughly investigated in populations at most risk for fragility fractures (i.e., elderly women). As part of the Malmö Osteoporosis Prospective Risk Assessment study (OPRA), we investigated 1044 randomly selected women, all 75 yr of age, with US of the phalanges and, for comparison, also with two more established methods for bone mass measurement: US of the calcaneus and dual-energy X-ray absorptiometry (DXA) of the hip and spine, both methods having an ability to predict fracture. A self-assessment questionnaire was used to obtain information on previous fracture and age at fracture event. We found a low correlation between US of the phalanges and US of the calcaneus speed of sound (SoS) (r = 0.11, p < 0.01), US of the calcaneus (stiffness) (r = 0.09, p < 0.05), DXA of the femoral neck (r = 0.09, p < 0.05), and DXA of the spine (r = 0.10, p < 0.01) and no significant correlation between US of the phalanges and US of the calcaneus broadband ultrasound attenuation (BUA) and DXA trochanter. Also, no differences in US of the phalanges were found when comparing women without any fracture with women with at least one fracture, whereas US of the calcaneus (SoS, BUA, and stiffness) and DXA of the femoral neck, trochanter, and spine were all lower in the women with a fracture history (p < 0.0001). In addition, the precision of the US of the phalanges method was evaluated and found to be lower in these elderly women, compared to the precision reported by others and the manufacturer. In summary, the present data indicate that US of the phalanges is not a usable tool for estimating fracture risk in an elderly female population.

Absorptiometry, Photon↗
PubMed2004

Using mobile DXA to improve access to osteoporosis care: unit design, program development, implementation, and outcomes.

Osteoporosis diagnosis and monitoring is best accomplished with dual X-ray absorptiometry (DXA), but technology availability can hinder access to care. We designed a mobile DXA program incorporating a Hologic Delphi-C trade mark bone densitometer housed in a specially configured 30-ft Winnebago trade mark. The mobile DXA program provided osteoporosis testing and education at the convenience of the patient's primary care site within our rural health care system. DXA results were sent electronically to the patient's physician within 48-72 h. The mobile DXA patient group tended to be older and at high risk for future fracture. The service provided was rated as excellent by patients. Given the volume of patients studied, the program was financially self-sustaining. Other healthcare systems or groups should consider development of a similar program.

Absorptiometry, Photon↗
PubMed2005

Reproducibility of DXA estimations of body fat in HIV lipodystrophy: implications for clinical research.

Dual-energy X-ray absorptiometry (DXA) estimates of body fat are increasingly used for the evaluation of human immunodeficiency virus lipodystrophy (HIV LD); however, limited data are available on their reproducibility. This information is essential for using this tool as an end point in treatment trials or as a diagnostic tool. This study evaluates the reproducibility of DXA body fat estimation in HIV-positive subjects with and without lipodystrophy. Thirty subjects representing a spectrum of severity of fat redistribution underwent same-day repeat whole-body DXA scans (Hologic QDR 4500A scanner). Root mean square coefficients of variation (RMS-CV) were used to estimate minimum detectable differences (MDDs) for body fat content in different regions. Absolute MDD was calculated by multiplying the MDD by the mean fat-mass value for each anatomical area. The RMS-CV ranged from 4.0% for arm fat to 1.6% for total fat. Relative and absolute MDD values ranged from 11.0% or 160 g for arm fat to 4.3% or 628 g for total fat. DXA measurements of regional body fat mass in subjects with HIV show similar reproducibility to other populations. Minimal detectable differences were smaller than differences observed in published studies for all measurements. DXA is a sensitive tool for detecting changes in peripheral fat among patients with HIV lipodystrophy.

Absorptiometry, Photon↗
PubMed2002

Bioelectrical impedance measures in different position and vs dual-energy X-ray absorptiometry (DXA).

BACKGROUND: Bioelectrical impedance analysis (BIA) is a safe, low-cost, non-invasive, rapid method for the assessment of body composition. It has therefore a great potential to be employed for epidemiological and clinical studies. However, many devices are available to estimate total body water (TBW), fat-free mass (FFM) and fat mass (FM) by bioelectrical impedance measurements. Moreover, bipedal devices allowing measurements in the only standing position are recently developed. They are easy and practical to use without operator, so a large diffusion can be forecasted in fields as sport and diet programs. Comparison of body composition estimation by a bipedal device with bioimpedance devices currently used, using dual-energy X-ray absorptiometry (DXA) as reference method. METHODS: The study was performed on 18 healthy women volunteers, age 32.0+/-10.7 years divided in two groups at different levels of body fatness. A Xitron 4000 impedance analyser, a BIA-101 RJL System, and the bipedal device Tanita were used for comparison. The measurements were performed in standing and supine position for Xitron and RJL devices. DXA measurements were performed with a total body scanner DPX, Lunar. RESULTS: FM and FFM were not statistically different when measured with Xitron and RJL in comparison with DXA, while these variables were significantly different between Tanita and DXA measurements. No significant difference were found between measurements in the supine and standing position with the Xitron and RJL system. CONCLUSIONS: Our results suggest that FM and FFM evaluated by bipedal device Tanita are significantly different from FM and FFM measured by DXA in both normal and obese population.

Absorptiometry, Photon↗
PubMed2005

Correlation between mechanical vibration analysis and dual energy X-ray absorptiometry (DXA) in the measurement of in vivo human tibial bone strength.

It is assumed that bone mineral density (BMD) measurement by dual-energy X-ray absorptiometry (DXA) has its limitation in identifying bone strength, and therefore other methods should be developed. Non-invasive strength measurement, which is needed to diagnose and monitor metabolic bone diseases such as osteoporosis, can become an alternative to current methods. In this study, mechanical vibration analysis was compared to BMD measured by DXA in human female tibia. Seven mother (Ms) and daughter (Ds) pairs' (total n = 14) left and right tibiae were evaluated by DXA and mechanical vibration analysis. Mechanical vibration analysis was consistent in the same bone and also in both sides. Correlation between BMD measured by DXA and vibration analysis was found in the Ds and Ms groups; the former being stronger than the latter. Natural frequencies of the Ms group were higher than that of the Ds group, and the response velocity of the Ds group was shorter than that of the Ms group. It is concluded that mechanical vibration analysis is consistent in bones and a correlation between BMD measured by DXA and vibration analysis can be established in young females that may be used in field studies to predict peak bone strength.

Absorptiometry, Photon↗
PubMedDate not supplied

Clinical practice guidelines proposed by the Hellenic Foundation of Osteoporosis for the management of osteoporosis based on DXA results.

In recent years guidelines for the testing and treatment of osteoporotic patients have been published by recognised organisations, including the World Health Organisation (WHO), the National Osteoporosis Foundation (NOF) and the International Osteoporosis Foundation (IOF). Dual Energy X-ray Absorptiometry (DXA) has been considered the technique of choice because of its excellent precision and ability to predict osteoporotic fractures. Last December, based on the Appraisal of the Guidelines for Research and Evaluation (AGREE), the Hellenic Foundation of Osteoporosis, in collaboration with other scientific societies, provided guidelines for the use of DXA for the diagnosis, monitoring and treatment of osteoporosis and Quality Assurance (QA) of these systems. According to these guidelines, the adequacy of the present number of DXA units in Greece was assessed. There are 367 DXA units in Greece, and almost 50% are located in the capital city, Athens, where 34.1% of the population lives. The distribution of DXA devices per resident in the Greek provinces (except Attica) is between 4.2 units/100,000 heads (Ionian Islands) and 1.6 units/100,000 heads (Sterea Hellas). These guidelines have resulted in a suggestive yearly repeat of the measurements, to ensure the precision of the method, but mainly for reasons of compliance. Finally, these guidelines are viewed as a work in progress and will be updated periodically in response to advances in this field.

Adult↗
PubMed1997

Maximising the cost effectiveness of BMD referral for DXA using ultrasound as a selective population pre-screen.

Bone mineral density (BMD) referral for dual energy X-ray absorptiometry (DXA) is generally based upon agreed clinical referral criteria (CRC). The aim of this study was to determine whether ultrasound measurements of Broadband UI-trasound Attenuation (BUA) and velocity (VOS) provide a superior selective pre-screen referral method for BMD assessment by DXA. 107 women aged 60-69 years (64.2 +/- 2.8) had BMD measurements at lumbar spine and right femoral neck along with ultrasound BUA and VOS measurements of the left calcaneus. Each subject completed an extensive clinical and social questionnaire to ascertain those who would have met one or more of the five general clinical referral criteria adopted by our Centre. Each subject was classified by DXA using the WHO criteria as normal, osteopenic or osteoporotic at lumbar spine or femoral neck. The cost per osteoporotic subject correctly identified was calculated. As a reference, based upon DXA measurements alone on all 107 subjects, the cost per osteoporotic subject identified would be Ponds 185. If subjects had been referred using the clinical referral criteria the cost is Ponds 171. For assessment of referral by BUA or VOS, an additional charge for ultrasound measurement of all subjects was incorporated. At a BUA of 60 dB MHz-1 the cost per osteoporotic subject is Ponds 107. Ultrasound velocity or a combination of BUA or VOS with clinical referral criteria did not provide a significantly reduced cost than the current clinical referral criteria alone. This study has demonstrated that BUA provides an improved referral procedure to that currently achieved with clinical referral criteria and supports the concept of BUA being used as a selective pre-screen for DXA in 7th decade subjects.

Absorptiometry, Photon↗
PubMed1997

Anthropometrics do not influence dual X-ray absorptiometry (DXA) measurement of fat in normal to obese adults: a comparison with in vivo neutron activation analysis (IVNA).

Dual-energy X-ray absorptiometry (DXA) is now a commonly used method for the determination of bone mineral status and body composition in humans. The purposes of this study were to compare fat mass by in vitro neutron activation analysis (FMIVNA) with that by DXA (FMDXA) in an anthropometrically heterogeneous sample of healthy adult men (n = 33) and women (n = 36) (19 < or = BMI < or = 39), and to determine whether differences in fat mass estimates between the two methods (delta FM) were attributable to subject anthropometry as defined by several circumference (waist, iliac crest, thigh) and skinfold thickness (umbilical, suprailiac, abdominal) measurements. No significant differences between FMDXA and FMIVNA were observed in men (p = 0.46) or women (p = 0.09). The two methods were very highly correlated in both sexes (women r2 = 0.97, p < 0.001, men r2 = 0.91, p < 0.001), although the regression line for men was significantly different from the line of identity (p = 0.043). These results suggest modest trends toward underestimation of FMDXA in men when FMIVNA < 18 kg, and overestimation in men when FMIVNA > 18 kg. delta FM (IVNA-DXA) was not significantly related to any combination of skinfold thickness and circumferences in either gender. Age explained 27% of the variance in delta FM for the men (p = 0.008). Furthermore, delta FM was not significantly related to inter-method disparity in total-body bone mineral measurements in men or women (p < 0.05). The present study demonstrates strong correlation in fat measurements between IVNA and DXA in men and women ranging from normal to markedly obese. Correction for subject anthropometry does not significantly improve this relationship.

Absorptiometry, Photon↗
PubMed1993

Geometric variables from DXA of the radius predict forearm fracture load in vitro.

The purpose of this investigation was to determine the cross-sectional geometry of the radius in female and male cadaveric specimens using dual-energy X-ray absorptiometry (DXA), to measure the accuracy of this technique compared with a digitizing procedure, and to measure the correlation between these DXA-based geometric variables and the load required to produce a forearm fracture. Paired intact forearms were scanned at a distal site and at a site approximately 30% of the forearm length from the distal end. The cross-sectional area and the moments of inertia of two sections at 10 and 30% of the forearm length were computed from the X-ray attenuation data. One member of each pair was then sectioned at the 30% location, which is mostly cortical bone, and the section was traced on a digitizing pad. The other forearm was loaded to failure in a servohydraulic materials test system. The DXA-based area and moment of inertia at 30% correlated significantly with the digitized results (r2 = 0.93 for area; r2 = 0.95 for moment; P < 0.001). The conventional bone mineral density from DXA did not associate significantly with failure load, but the minimum moment of inertia and the cross-sectional area at 10% correlated in a strong and significant manner with the forearm fracture force (r2 = 0.67 for area; r2 = 0.66 for moment; P < 0.001). The determination of radial bone cross-sectional geometry, therefore, should have better discriminatory capabilities than bone mineral density in studies of bone fragility and fracture risk.

Absorptiometry, Photon↗
PubMed2006

MRI-measured bone marrow adipose tissue is inversely related to DXA-measured bone mineral in Caucasian women.

INTRODUCTION: Recent studies suggest that bone marrow adipose tissue (BMAT) might play a role in the pathogenesis of osteoporosis. Previous research using regional magnetic resonance spectroscopy methods to measure BMAT has reported inconsistent findings on the relationship between BMAT and dual-energy absorptiometry (DXA)-measured bone mineral density (BMD). METHODS: In the present study, total body and pelvic BMAT were evaluated in 56 healthy women (age 18-88 yrs, mean +/- SD, 47.4 +/- 17.6 yrs; BMI, 24.3 +/- 4.2 kg/m(2)) with T1-weighted whole-body magnetic resonance imaging (MRI). BMD was measured using the whole-body DXA mode (GE Lunar DPX, software version 4.7). RESULTS: A strong negative correlation was observed between pelvic BMAT and BMD (total-body BMD, R = -0.743, P < 0.001; pelvic BMD, R = -0.646, P < 0.001), and between total-body BMAT and BMD (total-body BMD, R = -0.443, P < 0.001; pelvic BMD, R = -0.308, P < 0.001). The inverse association between pelvic BMAT and BMD remained strong after adjusting for age, weight, total body fat, and menopausal status (partial correlation: total-body BMD, R = -0.553, P < 0.001; pelvic BMD, R = -0.513, P < 0.001). BMAT was also highly correlated with age (pelvic BMAT, R = 0.715, P < 0.001; total-body BMAT, R = 0.519, P < 0.001). CONCLUSION: MRI-measured BMAT is thus strongly inversely correlated with DXA-measured BMD independent of other predictor variables. These observations, in the context of DXA technical concerns, support the growing evidence linking BMAT with low bone density.

Absorptiometry, Photon↗