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11,458 result(s) for "Absorptiometry"
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Updated practice guideline for dual-energy X-ray absorptiometry (DXA)
The introduction of dual-energy X-ray absorptiometry (DXA) technology in the 1980s revolutionized the diagnosis, management and monitoring of osteoporosis, providing a clinical tool which is now available worldwide. However, DXA measurements are influenced by many technical factors, including the quality control procedures for the instrument, positioning of the patient, and approach to analysis. Reporting of DXA results may be confounded by factors such as selection of reference ranges for T-scores and Z-scores, as well as inadequate knowledge of current standards for interpretation. These points are addressed at length in many international guidelines but are not always easily assimilated by practising clinicians and technicians. Our aim in this report is to identify key elements pertaining to the use of DXA in clinical practice, considering both technical and clinical aspects. Here, we discuss technical aspects of DXA procedures, approaches to interpretation and integration into clinical practice, and the use of non-bone mineral density measurements, such as a vertebral fracture assessment, in clinical risk assessment.
Update on the clinical use of trabecular bone score (TBS) in the management of osteoporosis: results of an expert group meeting organized by the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO), and the International Osteoporosis Foundation (IOF) under the auspices of WHO Collaborating Center for Epidemiology of Musculoskeletal Health and Aging
Purpose Trabecular bone score (TBS) is a grey-level textural measurement acquired from dual-energy X-ray absorptiometry lumbar spine images and is a validated index of bone microarchitecture. In 2015, a Working Group of the European Society on Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) published a review of the TBS literature, concluding that TBS predicts hip and major osteoporotic fracture, at least partly independent of bone mineral density (BMD) and clinical risk factors. It was also concluded that TBS is potentially amenable to change as a result of pharmacological therapy. Further evidence on the utility of TBS has since accumulated in both primary and secondary osteoporosis, and the introduction of FRAX and BMD T-score adjustment for TBS has accelerated adoption. This position paper therefore presents a review of the updated scientific literature and provides expert consensus statements and corresponding operational guidelines for the use of TBS. Methods An Expert Working Group was convened by the ESCEO and a systematic review of the evidence undertaken, with defined search strategies for four key topics with respect to the potential use of TBS: (1) fracture prediction in men and women; (2) initiating and monitoring treatment in postmenopausal osteoporosis; (3) fracture prediction in secondary osteoporosis; and (4) treatment monitoring in secondary osteoporosis. Statements to guide the clinical use of TBS were derived from the review and graded by consensus using the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach. Results A total of 96 articles were reviewed and included data on the use of TBS for fracture prediction in men and women, from over 20 countries. The updated evidence shows that TBS enhances fracture risk prediction in both primary and secondary osteoporosis, and can, when taken with BMD and clinical risk factors, inform treatment initiation and the choice of antiosteoporosis treatment. Evidence also indicates that TBS provides useful adjunctive information in monitoring treatment with long-term denosumab and anabolic agents. All expert consensus statements were voted as strongly recommended. Conclusion The addition of TBS assessment to FRAX and/or BMD enhances fracture risk prediction in primary and secondary osteoporosis, adding useful information for treatment decision-making and monitoring. The expert consensus statements provided in this paper can be used to guide the integration of TBS in clinical practice for the assessment and management of osteoporosis. An example of an operational approach is provided in the appendix. Summary This position paper presents an up-to-date review of the evidence base, synthesised through expert consensus statements, which informs the implementation of Trabecular Bone Score in clinical practice.
Methods for data analysis of resting energy expenditure measured using indirect calorimetry
•Reduced steady-state methods during 10 min of measurement overestimate the resting energy expenditure (REE).•Interval methods during 10 and 30 min of measurement overestimate the REE.•We recommend 5 min in steady state during 30 min of measurement to estimate the REE. The aim of this study was to test the accuracy of different methods of resting energy expenditure (REE) data analysis using indirect calorimetry (IC) during traditional (30 min) and abbreviated (10 min) protocols. Fifteen women and 15 men (21–34 y of age) completed two consecutive 30-min IC measurements. Body composition was measured using dual-energy x-ray absorptiometry. The reference method for REE analysis was 5 min in steady state (SS) during 30 min (first 5 min discarded). REE measurements were randomized to define a reference or testing method. An interval method was defined using 25, 20, and 15 min (with first 5, 10, and 15 min discarded, respectively), during 30 min, and 5 min (first 5 min discarded) during 10-min intervals. The SS method was defined using 5 min in SS (first 5 min discarded) during 30 min, 5, 4, and 3 min in SS during 10-min (first 5 min discarded) intervals. Interval methods during 30 min and SS and interval methods during 10 min demonstrated large bias with significantly high REEs compared to the reference method (78.8–109.0 kcal/d, all P < 0.001). Testing methods demonstrated large upper limits of agreement between 225.2 and 322.8 kcal/d. No mean differences (P > 0.05), small bias (14.3 kcal/d), and narrow limits of agreement (–125.8 to 154.4 kcal/d) were observed between 5-min SS during 30 min and the reference method. All interval methods and SS methods during 10 min overestimated REE. We recommend using 5-min SS during 30 min. The measurement may be repeated until all participants achieve SS.
Fracture prediction, imaging and screening in osteoporosis
Osteoporosis is associated with increased fragility of bone and a subsequent increased risk of fracture. The diagnosis of osteoporosis is intimately linked with the imaging and quantification of bone and BMD. Scanning modalities, such as dual-energy X-ray absorptiometry or quantitative CT, have been developed and honed over the past half century to provide measures of BMD and bone microarchitecture for the purposes of clinical practice and research. Combined with fracture prediction tools such as Fracture Risk Assessment Tool (FRAX) (which use a combination of clinical risk factors for fracture to provide a measure of risk), these elements have led to a paradigm shift in the ability to diagnose osteoporosis and predict individuals who are at risk of fragility fracture. Despite these developments, a treatment gap exists between individuals who are at risk of osteoporotic fracture and those who are receiving therapy. In this Review, we summarize the epidemiology of osteoporosis, the history of scanning modalities, fracture prediction tools and future directions, including the most recent developments in prediction of fractures.This Review highlights various medical imaging techniques and fracture prediction tools that are used to diagnosis osteoporosis and discusses the potential importance of screening in at-risk populations.
Imaging of sarcopenia: old evidence and new insights
To date, sarcopenia is considered a patient-specific imaging biomarker able to predict clinical outcomes. Several imaging modalities, including dual-energy X-ray absorptiometry (DXA), computed tomography (CT), magnetic resonance (MR), and ultrasound (US), can be used to assess muscle mass and quality and to achieve the diagnosis of sarcopenia. With different extent, all these modalities can provide quantitative data, being thus reproducible and comparable over time. DXA is the one most commonly used in clinical practice, with the advantages of being accurate and widely available, and also being the only radiological tool with accepted cutoff values to diagnose sarcopenia. CT and MR are considered the reference standards, allowing the evaluation of muscle quality and fatty infiltration, but their application is so far mostly limited to research. US has been always regarded as a minor tool in sarcopenia and has never gained enough space. To date, CT is probably the easiest and most promising modality, although limited by the long time needed for muscle segmentation. Also, the absence of validated thresholds for CT measurements of myosteatosis requires that future studies should focus on this point. Radiologists have the great potential of becoming pivotal in the context of sarcopenia. We highly master imaging modalities and know perfectly how to apply them to different organs and clinical scenarios. Similarly, radiologists should master the culture of sarcopenia, and its clinical aspects and relevant implications for patient care. The medical and scientific radiological community should promote specific educational course to spread awareness among professionals.Key Points• DXA is an accurate, reproducible, and widely available imaging modality to evaluate body composition, being the most commonly used radiological tool to diagnose sarcopenia in clinical practice• CT and MR are the gold standard imaging modalities to assess muscle mass and quality, but no clear cutoff values have been reported to identify sarcopenia, limiting the application of these modalities to research purposes• US has shown to be accurate in the evaluation of muscle trophism, especially in the thigh, but its current application in sarcopenia is limited
Current technologies in body composition assessment: advantages and disadvantages
The interest in non-invasive methods of body composition assessment is on the rise in health care, especially because of its association with clinical outcomes. Technology has revolutionized our understanding of body composition abnormalities, clinical prognostication, and disease follow-up, but translation to bedside is limited, especially in terms of cost effectiveness. Computed tomography gained increased attention in cancer and sarcopenia studies, for instance. Other methods also have interesting features and applications, including bedside ultrasonography, bioelectrical impedance analysis, and dual x-ray absorptiometry. Compelling evidence indicates these methods can be used to accurately and precisely measure skeletal muscle mass, adipose tissue, and edema; diagnose malnutrition-related diseases; and aid in determining prognoses. To apply this technology properly, it is important to understand the advantages and disadvantages of each technique in specific situations of interest. This review introduces concepts and reference studies published in the scientific literature about these techniques and describes important limitations and considerations necessary to incorporate these methods into clinical practice.
The evolution of bioimpedance analysis: From traditional methods to wearable technology
•BIA can provide important information pertaining to body composition.•Variations in physiological conditions that relate to fluid shifts may impact BIA estimations.•Wearable BIA devices provide home-based monitoring improving access to healthcare. Body composition assessments are essential for understanding health and nutritional status. Traditional methods like deuterium oxide dilution, while accurate, are impractical due to cost and complexity. Bioimpedance analysis (BIA) has emerged as a preferred clinical and research technique. BIA measures total body water and, by extension, fat mass and fat-free mass, based on constant hydration assumptions. Wearable BIA technology provides real-time body composition data, enhancing at-home monitoring. Although these devices show promise in measuring parameters like body fat percentage and skeletal muscle mass, accuracy discrepancies compared to methods like dual-energy X-ray absorptiometry and the 4-compartment model require further validation. Addressing user adherence and environmental limitations is essential for reliable results. This narrative review examines the current landscape of wearable BIA technology. Despite challenges, wearable BIA devices offer significant benefits, emphasizing ongoing innovation and validation.
X-ray-based quantitative osteoporosis imaging at the spine
Osteoporosis is a metabolic bone disease with a high prevalence that affects the population worldwide, particularly the elderly. It is often due to fractures associated with bone fragility that the diagnosis of osteoporosis becomes clinically evident. However, early diagnosis would be necessary to initiate therapy and to prevent occurrence of further fractures, thus reducing morbidity and mortality. X-ray-based imaging plays a key role for fracture risk assessment and monitoring of osteoporosis. Whereas over decades dual-energy X-ray absorptiometry (DXA) has been the main method used and still reflects the reference standard, another modality reemerges with quantitative computed tomography (QCT) because of its three-dimensional advantages and the opportunistic exploitation of routine CT scans. Against this background, this article intends to review and evaluate recent advances in the field of X-ray-based quantitative imaging of osteoporosis at the spine. First, standard DXA with the recent addition of trabecular bone score (TBS) is presented. Secondly, standard QCT, dual-energy BMD quantification, and opportunistic BMD screening in non-dedicated CT exams are discussed. Lastly, finite element analysis and microstructural parameter analysis are reviewed.
A Phase III Randomized Placebo-Controlled Trial to Evaluate Efficacy and Safety of Romosozumab in Men With Osteoporosis
Globally, one in five men aged >50 years is predicted to experience an osteoporotic fracture. Because of the treatment gap in osteoporosis and the paucity of bone-forming agents for men, new osteoporosis treatments are needed. To evaluate the safety and efficacy of romosozumab in men with osteoporosis. Phase III randomized BRIDGE study (placebo-controlled double-blind study evaluating the efficacy and safety of romosozumab in treating men with osteoporosis; ClinicalTrials.gov identifier, NCT02186171) for 12 months. Thirty-one centers in Europe, Latin America, Japan, and North America. Men aged 55 to 90 years with a baseline bone mineral density (BMD) T-score at the lumbar spine (LS), total hip (TH), or femoral neck of ≤-2.5 or ≤-1.5 with a history of a fragility nonvertebral or vertebral fracture. The subjects were randomized 2:1 to receive romosozumab 210 mg subcutaneously monthly or placebo for 12 months. The primary efficacy endpoint was percentage change from baseline in LS BMD at month 12. In 245 subjects (163 romosozumab, 82 placebo), at month 12, the mean percentage change from baseline in the LS and TH BMD was significantly greater for the romosozumab group than for the placebo group (LS, 12.1% vs 1.2%; TH, 2.5% vs -0.5%; P < 0.001). Adverse events and serious adverse events were balanced between the two groups, with a numerical imbalance in the positively adjudicated cardiovascular serious adverse events [romosozumab, 8 (4.9%) vs placebo, 2 (2.5%)]. Treatment with romosozumab for 12 months increased the spine and hip BMD compared with placebo and was well tolerated in men with osteoporosis.
A comparison of three methods to assess body composition
The aim of this study was to compare the accuracy of measurements of body composition made using dual x-ray absorptiometry (DXA), analysis of computed tomography (CT) scans at the L3 vertebral level, and bioelectrical impedance analysis (BIA). DXA, CT, and BIA were performed in 47 patients recruited from two clinical trials investigating metabolic changes associated with major abdominal surgery or neoadjuvant chemotherapy for esophagogastric cancer. DXA was performed the week before surgery and before and after commencement of neoadjuvant chemotherapy. BIA was performed at the same time points and used with standard equations to calculate fat-free mass (FFM). Analysis of CT scans performed within 3 mo of the study was used to estimate FFM and fat mass (FM). There was good correlation between FM on DXA and CT (r2 = 0.6632; P < 0.0001) and FFM on DXA and CT (r2 = 0.7634; P < 0.0001), as well as FFM on DXA and BIA (r2 = 0.6275; P < 0.0001). Correlation between FFM on CT and BIA also was significant (r2 = 0.2742; P < 0.0001). On Bland–Altman analysis, average bias for FM on DXA and CT was 0.2564 with 95% limits of agreement (LOA) of –9.451 to 9.964. For FFM on DXA and CT, average bias was –0.1477, with LOA of –8.621 to 8.325. For FFM on DXA and BIA, average bias was –3.792, with LOA of –15.52 to 7.936. For FFM on CT and BIA, average bias was –2.661, with LOA of –22.71 to 17.39. Although a systematic error underestimating FFM was demonstrated with BIA, it may be a useful modality to quantify body composition in the clinical situation. •The present study compared the accuracy of measurements of body composition made using dual x-ray absorptiometry (DXA), analysis of computed tomography (CT) scans, and bioelectrical impedance analysis (BIA).•DXA, CT, and BIA were performed in 47 patients recruited from two clinical trials.•Although a systematic error underestimating fat-free mass was demonstrated with BIA, it may be a useful modality to quantify body composition in a clinical situation.