Dual-energy Photon Absorptiometry Research Articles

<p>Bone-mineral density: clinical significance, methods of quantification and forensic applications</p>

Bone-mineral density (BMD) is a measure of the inorganic mineral content inbone, and is one of the more informative assessments of bone quality in both clinical studiesand forensic investigations. Several factors, such as age, sex, disease, genetics, and lifestyle,affect BMD measurements, and normative standards must be applied for specific groups andindividuals. One of the most common disorders associated with low BMD is osteoporosisand increased fracture risk, due to a decrease in bone strength and an increase in bonefragility. Medical conditions like diabetes or hyperthyroidism and other parameters like peakbone mass and postmenopausal estrogen deficiency also impact BMD. Single- and dual-energy photon absorptiometry, quantitative computet tomography, and magnetic resonanceimaging are some of the technological modalities for BMD quantification, and each presentsdistinct advantages and limitations, depending on the purpose of the analysis, the specificcharacteristics of the individual, the bone site under examination, and the equipment andtrained personnel available. Recently, BMD values were applied to forensic medicine in avariety of scenarios ranging from age and sex estimation to the assessment of malnutritionand the use offinite-element modelling. Despite technical and methodological inconsisten-cies reported in the literature on BMD readings, there is scope for expanding the use of thisvariable in forensic settings (4) (PDF) Bone-mineral density: clinical significance, methods of quantification and forensic applications. Available from: https://www.researchgate.net/publication/334676972_Bone-mineral_density_clinical_significance_methods_of_quantification_and_forensic_applications [accessed Aug 22 2019].

The Effect of Surrounding Fat on Measurment of Bone Mineral Density (BMD) by Dual Energy Photon Absorptiometry (DXA) a High Resolution Peripheral Quatitative Computerized Tomography (HR-pQCT)

The Effect of Surrounding Fat on Measurment of Bone Mineral Density (BMD) by Dual Energy Photon Absorptiometry (DXA) a High Resolution Peripheral Quatitative Computerized Tomography (HR-pQCT)

The effect of anterior cruciate ligament surgery on bone mineral in the calcaneus: a prospective study with a 2-year follow-up evaluation

Purpose: The goal of this study was to evaluate the effect of anterior cruciate ligament (ACL) reconstruction on the bone mineral area mass (BMA) in the calcaneus on the injured and noninjured sides. Type of Study: A prospective cohort study with sequential assessments of bone mineral in the calcaneus before and after ACL reconstruction. Methods: Thirty-four consecutive patients with a unilateral ACL rupture underwent arthroscopic reconstruction using patellar tendon autografts. The BMA was assessed bilaterally in the calcaneus using a gamma camera according to the dual-energy photon absorptiometry technique, before surgery and after 6 and 26 months. Results: Thirty-one of 34 patients (20 men and 11 women) underwent all BMA measurements. The median age at index surgery was 27 (16 to 50) years, and the reconstruction was performed 12 (2 to 192) months after the injury. The median preoperative Tegner activity level increased from 3 (2 to 8) to 7 (2 to 9) at 26 months ( P < .0001). The BMA in the calcaneus on both the injured and noninjured side decreased by 16% and 17% respectively from the preoperative measurement to the 26-month control ( P = .0014; P = .0006). On all occasions, the BMA was lower on the injured side than on the noninjured side ( P = .012). Conclusions: Patients with a unilateral ACL rupture had a lower BMA in the calcaneus on the injured side compared with the noninjured side. Although patients increased activity levels after reconstruction, the BMA in the calcaneus decreased on both the injured and the noninjured side up to 2 years after surgery. Level of Evidence: Level II-1, prospective cohort study.

Oral budesonide and ursodeoxycholic acid for treatment of primary biliary cirrhosis: Results of a prospective double-blind trial

Background & Aims: Ursodeoxycholic acid (UDCA) is used for treatment of primary biliary cirrhosis. Previous studies showed that, compared with UDCA monotherapy, bile salts plus prednisolone had no further effect on laboratory data but improved liver histology. Thirty percent of these patients had prednisolone-related side effects. Budesonide is a glucocorticoid with a high receptor affinity and a high first-pass metabolism. In this study we investigated whether budesonide and UDCA are superior to UDCA monotherapy. Methods: A 2-year prospective, controlled double-blind trial was performed. Twenty patients (mainly with early-stage disease) were treated with UDCA at a dose of 10-15 mg/kg daily in addition to 3 mg budesonide 3 times daily (group A), and 19 patients (1 dropped out for personal reasons) were treated with UDCA plus placebo (group B). Liver biopsy specimens were taken before, after 12 months, and at the end of study. Glucose tolerance tests, serum cortisol levels, and adrenocorticotropin-stimulated cortisol secretion were assessed at regular intervals. Bone mass density was measured by dual-energy photon absorptiometry. Results: Compared with pretreatment values, liver enzyme and immunoglobulin M and G levels decreased significantly in both groups. Improvement in group A was significantly more pronounced ( P < 0.05) than in group B. Titers of antimitochondrial antibodies did not change. In group A, the point score of liver histology improved by 30.3%; in group B, it deteriorated by 3.5% ( P < 0.001). Changes in bone mineral density after 2 years were −1.747% in group A and −0.983% in group B ( P = 0.43). Budesonide had little influence on the hypothalamic-pituitary-adrenal axis. One patient in group A had budesonide-related side effects; in 3 patients in group B, complications of liver disease developed. Conclusions: Combination therapy with UDCA and budesonide is superior to UDCA and placebo. GASTROENTEROLOGY 1999;117:918-925

A Structural Approach to Renal Bone Disease

A Structural Approach to Renal Bone Disease

Comparison of body composition methods: a literature analysis

To examine the comparability of different methods to assess percentage body fat (BF%) against underwater weighing (UWW). A meta-analysis on 54 papers, published in 1985-96, on healthy, adult Caucasians. The mean BF% from different studies were treated as single data points. In addition to UWW, the studies included one or more of the following methods: 3- or 4-component model, dual-energy X-ray absorptiometry (DXA), dual-energy photon absorptiometry, isotope dilution, bioimpedance (BIA), skinfolds or near-infrared interactance (NIR). Within each of the methods, the analyses were done separately for different mathematical functions, techniques or instruments. Bias (mean difference) and error (s.d. of difference) between BF% measured by UWW and the other methods. The 4-component model gave 0.6 (95% confidence interval for the mean, CI: 0.1 to 1.2) BF% higher results than UWW. Also the 3-component model with body density and total body water (+1.4 BF%, 95% CI: +0.3 to +2.6), deuterium dilution (+1.5 BF%, 95% CI: +0.7 to +2.3), DXA by Norland (+7.2 BF%, 95% CI: 2.6 to 11.8) and BIA by Lukaski et al. (+2.0 BF%, 95% CI: 0.2 to 3.8) overestimated BF%, whereas BIA by Valhalla Scientific (-2.6 BF%, 95% CI: -4.5 to -0.6) and skinfold equations by Jackson et al. (-1.20, 95% CI: -2.3 to -0.1) showed a relative underestimation. The mean bias for the skinfold equation by Durnin & Womersley, against UWW, was 0.0 BF% (95% CI: -1.3 to 1.3). The correlation between the size of measurement and the mean difference was significant for only NIR (r = -0.77, P = 0.003). The difference between any method and UWW is dependent on the study. However, some methods have a systematical tendency for relative over- or underestimation of BF%.

Bone mineral densitometry in dialyzed patients: Quantitative computed tomography versus dual photon absorptiometry

Reduced bone mineral density (BMD) increases risk of fractures, thus making if: necessary to monitor patients suffering from chronic renal failure and consecutive disturbance of bone metabolism. In order to evaluate the reliability of available methods, bone mineral density of the lumbar spine assessed with single energy computed tomography (QCT) was compared with bone mineral density of the lumbar spine, femoral neck, Ward's triangle and trochanteric region measured by dual energy photon absorptiometry (DPA) in 45 hemodialyzed patients with a mean hemodialysis duration of 35 ± 26 months (SD). Depending on the measurement site and method 4–34% of dialyzed patients suffered from reduced BMD (z-score < −2). The highest correlation ( r = 0.61, p < 0.01) was found between QCT of the spine, trabecular bone, and DPA of Ward's triangle. One year after baseline measurement bone mineral density was reassessed after randomization to either QCT or DPA in 14 and 18 patients, respectively. Whereas lumbar spine and femoral neck did not change, mean BMD showed a decrease at the measurement sites of Ward's triangle (DPA), trochanteric region (DPA) and trabecular bone of the spine (QCT), which, however, was statistically not significant. Cortical BMD of the spine assessed with QCT showed an increase. Although there is some reduction in bone density at most sites in hemodialyzed patients, no significant bone loss could be demonstrated over the course of 1 year.

Osteoporosis, Metabolic Aberrations, and Increased Risk for Vertebral Fractures After Partial Gastrectomy

A case-control study compared 129 men with earlier partial gastrectomy (operation during the period 1952-1961) with 216 men from a community-based population study. All were born 1910-1915 and the mean age was 72 years. Men with a previous partial gastrectomy had vertebral fractures in 19% compared with 4% (P < 0.01) in the control population. Bone mineral density (BMD) in the right calcaneus measured with dual energy photon absorptiometry was 20% lower in men with a Billroth II operation (P < 0.001) and 8% lower with a Billroth I operation (ns). In comparison with the controls, the men subjected to partial gastrectomy had higher serum concentrations of osteocalcin and alkaline phosphatase activity, a lower serum concentration of 25-hydroxyvitamin D (25OHD) and a lower body mass index (BMI). There were no difference in serum concentrations of free calcium, intact parathyroid hormone (PTH), or free thyroxine. The smoking prevalence was significantly higher in men with partial gastrectomy than in controls. Smokers had significantly lower serum concentrations of intact PTH and 25OHD than nonsmokers and also lower BMD and BMI. The relationships between intact PTH on one hand, and ionized calcium (inverse relationship) and osteocalcin (direct relationship) on the other were preserved in smokers, however. Gastroscopy was performed in 78 men with multiple biopsies in the gastric remnant and also in the small intestine. All but two subjects had chronic gastritis. Examination of sternal bone marrow smears showed that 40% of the Billroth-operated men lacked bone marrow reticular iron.(ABSTRACT TRUNCATED AT 250 WORDS)

Regional variations in bone mineral density as assessed with dual-energy photon absorptiometry and dual x-ray absorptiometry.

Total-body, lumbar spine, and hip bone mineral density (BMD) scans were obtained in postmenopausal women to examine regional variations in mineralization of trabecular bone. One hundred ninety-nine patients were studied with dual-energy photon absorptiometry (DPA) and/or dual x-ray absorptiometry (DXA). Comparison of BMD at the different sites showed statistically significant correlations (P < .001) among all the sites; however, variations between sites were observed in many patients. Total-body measurements were within normal limits as defined by the system software in 90% of patients with substantial bone mineral loss in the spine or hip. Lumbar spine measurements calculated from the total-body scan differed from the direct measurements by an average of 10% (DPA) and 12% (DXA). These results suggest that site-specific measurements are required to assess regional osteopenia. While total-body scans may be precise and offer the advantage of total-body composition determination, BMD values derived from total-body scans cannot currently replace direct measurements.

Fracture prevalence and bone mineral mass in osteoporosis measured with computed tomography and dual energy photon absorptiometry.

In 174 adults presenting with backache, bone densitometry was performed on the lumbar spine, both femoral necks, and one femoral shaft employing dual energy photon absorptiometry (DPA); in 112 of these, densitometry was undertaken on L4 using single energy quantitative computer assisted tomography (CT). Radiographs of the spine were obtained in all patients and those with known or suspected malignant disease were excluded. The subjects were divided into two groups according to the presence (n = 128) or absence (n = 44) of signs of vertebral collapse or compression. The predictive value of the densitometric results for the presence of vertebral fractures was calculated and used as an estimate of fracture risk. While CT showed somewhat higher predictive values than DPA of the spine or combinations of DPA results from spine and femoral necks, the difference was not significant. It is concluded that with both CT and DPA the probability of the presence or absence of fracture can be raised to 75-80% when the probability prior to the investigation is 50% and when the threshold values of the measurements are chosen so that their sensitivity and specificity are about equal.