RESUMO

Dual-energy X-ray absorptiometry is recognized for measuring bone mineral density. The lack of knowledge can lead to errors both in the acquisition of information and in its analysis and subsequent interpretation. The main errors in Ecuadorian Centers were positioning of the patient to the equipment and incorrect analyzed area. PURPOSE/INTRODUCTION: Dual-energy X-ray absorptiometry (DXA) is recognized as the gold standard for measuring bone mineral density (BMD) with acceptable errors, good precision, and reproducibility. However, the training of operators in different centers and countries is not standardized, and the lack of knowledge can lead to errors both in the acquisition of information and in its analysis and subsequent interpretation. The purpose was to determine the most common errors in the performance of bone densitometry from different imaging centers in Ecuador. METHODS: Cross-sectional descriptive study. We collected DXA scans from different imaging centers in Ecuador. Data from the DXA scan included city of origin, type of specialist that requested it, and densitometry diagnosis. The DXA images provided were analyzed double blind by experts in the field from Argentina. RESULTS: From a total of 141 patients with a mean age of 61 ± 10 years, 93.6% were women. About 78% of the DXA scans came from private imaging centers and 22% from public centers, 95% of all came from the city of Guayaquil. The machines used were Hologic 50.4% and Lunar 49.6%. The densitometric diagnosis was 16.3% normal, 46.1% osteoporosis, and 37.6% osteopenia. A total of 112 left hip and 49 right hip scans were analyzed from which 31.2% and 22.4% had errors in patient positioning, respectively, mainly internal or external rotation. About 140 lumbar scans were analyzed from which 21.4% had patient positioning errors (not centered or not straight). Also in 38.5% the vertebral area did not correspond to L1-L4. About 3.5% had artifacts such as a metal bar or implant. The region of interest was misplaced in 24.1% of the lumbar scans and 19.9% of the femur. CONCLUSIONS: DXA quality standards exist but are often not implemented in clinical practice. When studies are performed incorrectly, it can lead to important errors in diagnosis and therapy. Physicians interested in the management of osteoporosis, although not directly involved in the performance and interpretation of DXA, should be familiar with the protocols to minimize errors and allow the proper use of bone densitometry.

Assuntos

RESUMO

Nascimento, MA, Silva, DRP, Ribeiro, AS, Pina, FLC, Gerage, AM, Gobbo, LA, Mayhew, JL, and Cyrino, ES. Agreement between bioelectrical impedance and dual-energy x-ray absorptiometry to track changes in fat-free mass after resistance training in older women. J Strength Cond Res 34(6): 1700-1708, 2020-The aim of our study was to compare the agreement between bioelectrical impedance (BIA) and dual-energy X-ray absorptiometry (DXA) to track changes on fat-free mass (FFM) after a resistance training (RT) program in older women. Forty-three older women (65.2 ± 4.6 years, 59.5 ± 9.2 kg, 156.4 ± 6.0 cm, 24.3 ± 3.3 kg·m) participated in a RT intervention (12 weeks, 8 exercises, 2 sets, 10-15 repetitions, 3 nonconsecutive days per week). Fat-free mass changes were determined by a single-frequency BIA device (EQ1), 6 BIA prediction equations for older women (EQ2, EQ3, EQ4, EQ5, EQ6, and EQ7), and DXA. At pretraining, 3 equations overpredicted, and 3 underpredicted DXA FFM (F = 244.63, p < 0.001), although all equations had high correlations with DXA (r = 0.78-0.83). After training, 4 equations overpredicted and one underpredicted DXA FFM (F = 176.25, p < 0.001). Dual-energy X-ray absorptiometry detected significant gains in FFM (0.65 ± 0.82 kg; p < 0.05), as did EQ3 (0.55 ± 1.69 kg; p < 0.05), and EQ4 (0.61 ± 1.88 kg; p < 0.05), whereas the remaining equations did not indicate significant changes in FFM. Low correlations between FFM and equation change values suggest that single-frequency BIA-derived equations may not provide sufficient accuracy to track changes in FFM after 12 weeks of RT in older women.

Assuntos

RESUMO

Vertebral fracture (VF) is the most common type of osteoporotic fracture. VFs are associated with a decline in quality of life and high morbidity and mortality. The presence of a VF is a significant risk factor for developing another fracture; however, most VFs are not clinically recognized and diagnosed. Vertebral fracture assessment by dual-energy X-ray absorptiometry is a low cost, low radiation, convenient, and reliable method to identify VFs. The finding of a previously unrecognized VF may change the assessment of fracture risk, diagnostic classification, and treatment strategies. Vertebral fracture assessment or radiographic lateral spine imaging should be repeated in patients with continued high risk for fracture (e.g., historical height loss >4 cm [>1.5 inches], self-reported but undocumented vertebral fracture, or glucocorticoid therapy equivalent to ≥5 mg of prednisone or equivalent per day for greater than or equal to 3 months).

Assuntos

RESUMO

Osteoporosis is a silent and frequent disease, which increases fracture risk. Approximately half of women and one of five men over 50 years old will suffer an osteoporotic fracture throughout their lives. Dual-energy x-ray absorptiometry (DXA) allows a real bone mineral density (BMD) measurement in different parts of the skeleton and is considered the "gold standard" for quantifying osteoporosis with high accuracy and precision. The Board of the Chilean Society of Endocrinology and Diabetes (SOCHED) required from the Bone Disease Study Group to develop a consensus about the "Correct use of bone densitometry in clinical practice in Chilean population". Therefore, we elaborated 25 questions which addressed key aspects about the indications for a DXA scan, and the details of how to perform and report this test. Since some of the evidence obtained was of low quality or inconclusive, we decided to create a multidisciplinary group of national experts in osteoporosis to develop a consensus in this subject. The group consisted of 22 physicians including endocrinologists, gynecologists, geriatricians, radiologists, rheumatologists and nuclear medicine specialists. Using the Delphi methodology to analyze previously agreed questions, we elaborated statements that were evaluated by the experts who expressed their degree of agreement. The final report of this consensus was approved by the SOCHED board.

Assuntos

RESUMO

Osteoporosis is a silent and frequent disease, which increases fracture risk. Approximately half of women and one of five men over 50 years old will suffer an osteoporotic fracture throughout their lives. Dual-energy x-ray absorptiometry (DXA) allows a real bone mineral density (BMD) measurement in different parts of the skeleton and is considered the "gold standard" for quantifying osteoporosis with high accuracy and precision. The Board of the Chilean Society of Endocrinology and Diabetes (SOCHED) required from the Bone Disease Study Group to develop a consensus about the "Correct use of bone densitometry in clinical practice in Chilean population". Therefore, we elaborated 25 questions which addressed key aspects about the indications for a DXA scan, and the details of how to perform and report this test. Since some of the evidence obtained was of low quality or inconclusive, we decided to create a multidisciplinary group of national experts in osteoporosis to develop a consensus in this subject. The group consisted of 22 physicians including endocrinologists, gynecologists, geriatricians, radiologists, rheumatologists and nuclear medicine specialists. Using the Delphi methodology to analyze previously agreed questions, we elaborated statements that were evaluated by the experts who expressed their degree of agreement. The final report of this consensus was approved by the SOCHED board.

Assuntos

RESUMO

OBJECTIVES: Ultrasound (US) imaging is a low-cost, highly feasible alternative method for monitoring the nutritional status of a population; however, only a few studies have tested the body composition agreement between US and reference standard methods, especially in adolescents. The purposes of this study were to assess the agreement of portable US with a reference standard method, dual-energy x-ray absorptiometry (DXA), for body fat percentage (BF%) in adolescents and to verify whether the use of a new mathematical model, based on the anatomic thickness obtained by US, is capable of improving BF% prediction. METHODS: This research was a descriptive study. Measures of total body mass, BF% on DXA, and BF% on US were collected from 105 adolescents. RESULTS: The participants included 71 male adolescents (median age ・} interquartile range, 14.0 ・} 2.0 years) and 34 female adolescents (13.0 ・} 2.3 years). Ultrasound yielded significantly lower BF% values than DXA for male (mean ・} SD, US, 9.6% ・} 6.6%; DXA, 20.0% ・} 7.2%; R= 0.848; P< .05) and female (US, 22.5% ・} 5.7%; DXA, 30.3% ・} 4.9%; R = 0.495; P < .05) participants. In addition, Bland-Altman analysis showed low concordance. When a multivariate regression was tested, the results improved for both sexes (US, 20.3% ・} 4.6%; R= 0.848; P= .503) and female participants (US, 29.0% ・} 5.7%; R= 0.712; P = .993) with a standard estimate of error of 1.57%. CONCLUSIONS: This study has shown that US applied in a specific regression for BF% prediction in adolescents

Assuntos

RESUMO

OBJECTIVE: The aims of this study were to validate BOD POD in a wide sample of healthy and independent Mexican elderly men and women subjects using the 4 compartment (4C) model as the reference method, and to evaluate the assumptions of the densitometric two-compartment (2C) model. DESIGN: Cross-sectional study designed to assess body composition and validation of a method based on 2C model (BOD POD). SETTING: Urban and rural regions of Sonora, Mexico. SUBJECTS: Two hundred and two free-living subjects >or=60 years old were completed in this study. METHODS: Body density and body fat were measured by the BOD POD, total body water by deuterium dilution and total body bone ash by dual energy X-ray absorptiometry. Body composition was determined using Baumgartner's equation. RESULTS: Percent body fat by the 4C model was 31.2 and 42.5% in men and women, respectively (P<0.001). Group mean accuracy of body fat by BOD POD against that of the 4C model showed an effect of sex (P<0.001), but not the method (P=0.27). Results of individual accuracy showed no significant difference with the identity line and the slope was significantly different from zero or a slope similar to one. Precision assessed by model R (2) was high for all subjects and for men and women by separate. The standard error of the estimate was low for all and for men and women by separate. Bland and Altman analysis showed no significant bias. CONCLUSION: The BOD POD technique is a valid and reliable method compared to the 4C model and it could be applied in subjects with similar physical and anthropometric characteristics to subjects of this study.

Assuntos

RESUMO

Technologies for the measurement of bone mineral density and other parameters of bone strength at peripheral skeletal sites have been studied since the 1960s. Single-energy Photon Absorptiometry (SPA), Radiographic Absorptiometry (RA), Radiogrametry (RG), Single-energy X-ray Absorptiometry (SXA), Peripheral Dual-energy X-ray Absorptiometry (pDXA), and Quantitative Ultrasonometry (QUS) have been successively evaluated. These technologies and their clinical applications are discussed in this article. The available scientific evidence supports the clinical use of these technologies at peripheral skeletal for assessment of fracture risk. Peripheral measurements other than the 33% (one-third) radius by DXA cannot be used to diagnose osteoporosis according to current standards. Peripheral skeletal sites are not clinically useful for monitoring changes in BMD with natural evolution of the disease and its treatment. Peripheral BMD measurement can theoretically be used to screen patients for selection to central DXA testing, although device-specific cut-points should be developed before this is implemented. When central DXA testing is not available, peripheral BMD testing may be considered to identify individuals who might benefit from pharmacological intervention.

Assuntos

Assuntos

RESUMO

Anterior, middle, and posterior heights and A/P and M/P ratios were determined from T5 to L4 in 111 normal Caucasian Argentine women from 20 to 70 years of age using dual energy X-ray absorptiometry (DXA) densitometry (Expert XL). Scanning time was less than 1 minute and the semiautomatic analysis requires approximately 5 minutes. The precision error for the measurements ranged from 2.2% to 4.6%. The absolute precision error for heights was 0.6 mm. The vertebral bodies tended to be significantly larger in younger women than older women, especially for anterior and middle heights and the A/P and M/P ratios of the midthoracic vertebrae (T6-T10). There were no significant differences between pre- and postmenopausal women in the lumbar vertebral heights. It does not appear that this was a cohort effect because stature was identical in both age groups, and there was no age difference in posterior height. The Expert-XL software normalized the vertebral height based on the average height of the L2-L4 segment in order to minimize the influence of interindividual variation of body size. The average Z-scores for vertebral heights and ratios provided by the software were close to zero indicating that the normalization procedure appropriately corrected for smaller stature in Argentine women. Consequently, the reference values for morphometry X-ray absorptiometry (MXA) were appropriate for our population. In summary, we found that (1) in "normal" women the anterior heights of the thoracic vertebrae (and therefore the A/P ratio) were higher in premenopausal than in postmenopausal women; and (2) the normalization approach corrected for differences of vertebral height and allowed utilization of the manufacturers software in our population.

Assuntos