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At least 235 records · Page 13Linked to original sources

PubMed1989

Estimation of total body composition from single photon absorptiometry measurement of forearm fat content.

The forearm fat content (FATarm, measured by single photon (125I) absorptiometry) and the 24-h urinary creatinine excretion (24 Ucrea) were determined in 29 healthy adults (12 males and 17 females), whose total body fat percentage was measured by three different methods: (i) Dual photon (153Gd) absorptiometry (DPA); (ii) body density measurements (BD); and (iii) total body potassium determinations (TBP). Lean body mass (by DPA, BD, and TBP) correlated significantly with 24 Ucrea (r = 0.87-0.89, standard error of estimate (SEE) = 5.2-6.3 kg). The total body fat percentage could be predicted from FATarm with SEEs at 3.4-5.8 (r = 0.85-0.88) and from 24 Ucrea + body weight with SEEs at 5.1-7.5 (r = 0.61-0.72). We conclude that the FATarm measurement represents a new tool for simple assessment of body composition on a group basis.

Adipose Tissue↗

PubMed1983

Bone mineral content of femoral bone and the lumbar spine measured in women with fracture of the femoral neck by dual photon absorptiometry.

The bone mineral content (BMC) in the lumbar spine, femoral neck, and femoral shaft in 46 women ranging in age from 60 to 89 years with fractures of the femoral neck was measured by dual photon absorptiometry and compared with that of 38 healthy women in the same age group. For BMC of the lumbar spine and femoral neck there was no significant difference between the fracture group and the control group, whereas BMC of the femoral shaft was significantly reduced in the fracture group. No significant difference was found between BMC values for the 18 transcervical and 28 pertrochanteric fractures. Radiographic evidence of osteoporosis with compression fractures of vertebrae could be demonstrated in ten of the patients with femoral neck fractures. There was a significant correlation between BMC of the axial and peripheral skeleton in the patients with fractures. The Singh Index was significantly correlated with BMC of the lumbar spine but not with that of the femoral neck or shaft. It is concluded that the high incidence of femoral neck fracture with increasing age might be explained in part by a reduction in BMC, primarily cortical bone mineral, but it is likely that other factors that reduce the strength of bone or increase the tendency in older persons to fall are also of importance.

Aged↗

PubMed1981

The comparison of neutron activation analysis and photon absorptiometry at the same part-body site.

Two non-invasive methods of bone measurement were, for the first time, compared at the dame part-body site. Bone calcium, using in vivo neutron activation analysis, and bone mineral, using photon absorptiometry, were measured in the forearm in a group of renal patients. A highly significant correlation was obtained from absolute values (r = 0.91) which was reduced after normalisation (r = 0.75). Percentage changes, over periods totalling 31.3 patient years, were also highly significantly correlated (r = 0.61, P less than 0.001). The precision of the techniques accounts for the spread of the bivariate data and the estimated line of the true relationship was not significantly different from the line described if the percentage changes measured by the two techniques were equal. The two basic techniques were shown to be equally sensitive in vivo methods for monitoring calcified bone in patients suffering from metabolic bone disease.

Absorption↗

PubMed1984

Marked disparity between trabecular and cortical bone loss with age in healthy men. Measurement by vertebral computed tomography and radial photon absorptiometry.

To define age-related changes in bone mineral content in normal men, we measured radial (proximal and distal) and vertebral bone mineral content in 62 men aged 30 to 92 years. Radial bone mineral content (largely cortical bone) was measured by single photon absorptiometry, and trabecular vertebral content (T12, L1 to L3) by computed tomography. Radial bone mineral content fell gradually (2% to 3.4% per decade) with age, but vertebral trabecular content fell more rapidly (12% per decade). Body size was not associated with the rate of bone loss from the distal radial and vertebral sites, but men with lower surface areas lost bone more rapidly at the predominantly cortical proximal radial site. The fact that radial cortical bone mineral content falls much less rapidly than vertebral trabecular content with age and is also associated with surface area indicates that trabecular and cortical bone compartments may be independently modulated. Age-related bone loss should not be considered a homogeneous process.

Adult↗

PubMed1988

Bone metabolism following gastric surgery: microdensitometry and single-photon absorptiometry.

The impairment of bone metabolism was investigated in patients who underwent gastrectomy or vagotomy with drainage two or more years ago. Serum biochemical analysis, microdensitometry of the 2nd metacarpal bone, and measurements of bone mineral content of the radius (measured 1/3 distally) using single-photon absorptiometry were performed at follow-up examination. Although serum levels of calcium, phosphorus and alkaline phosphatase were within normal range, alkaline phosphatase levels were slightly higher for the Billroth II group than for Billroth I. Twenty-eight of 50 gastrectomy cases (56%), and four of 10 vagotomy cases (40%) showed pathologically thin bone: microdensitometric (MD) scores were greater than 3. The Billroth II group showed a far higher frequency of greater MD scores than Billroth I. The MD scores showed significant positive relationship with the age at follow-up, but did not correlate well with the length of the postoperative period. Radial bone mineral content (BMC) was lower in patients with Billroth II anastomosis, or with total or proximal gastrectomy, than in those undergoing Billroth I. These results suggest that metabolic bone disorders following gastric surgery can be detected by MD score and BMC of appendicular bones. However, there was not sufficient resolution with these parameters to detect any bone changes in patients treated with active vitamin D3.

Adult↗

PubMed1988

Total body and regional bone mineral analysis by dual-photon absorptiometry in Paget's disease of bone.

Total body density (TBD), total body bone mineral (TBBM) and bone mineral content of major anatomical skeletal areas were measured in 66 patients with Paget's disease of bone (54 polyostotic; 12 monostotic; 38 males; 28 females; 38-88 years), by dual-photon absorptiometry (153 Gd). TBD was elevated in 23 males and three females with Paget's disease; a statistically significant correlation was found between elevated values of TBD and a widespread extent of the disease. The mean value of TBBM was higher in pagetic males, while in pagetic females it was similar to normal subjects. The separate analysis of anatomical areas allowed us to appreciate increased values of bone mineral content in head, trunk, spine, pelvis, arms. Moreover in 28 patients with easily detectable pagetic lesions of long bones, 38 specific regions of interest (ROI) were evaluated: pagetic areas showed significantly higher values of bone density and bone mineral content in comparison with contralateral uninvolved areas.

Adult↗

PubMed1988

Bone mineral content of the hyperprolactinemic rat femur by single photon absorptiometry.

Chronic hyperprolactinemia was obtained in the rat by an implantation of two adenohypophyses under the kidney capsule. This experimental model was set to evaluate the influence that high prolactin levels may have on bone mineralization when an intervention of estrogens can reasonably be excluded. Bone density was measured by single photon absorptiometry at the femur level. Our results indicate that the increase in PRL throughout the period of observation was associated with a significant decrease in bone mineral content, while calcium and parathyroid hormone serum levels remained unchanged. This would suggest that PRL plays a role in bone calcium metabolism, that might be included among the effects of this hormone.

Animals↗

PubMed1974

Measurement of bone mineral content in vivo using photon absorptiometry.

Progress in evaluating treatment of systemic bone disease has been hampered in the past by lack of precise in vivo quantitative techniques. Recently a method has been developed for measurement of bone mineral content (BMC), based on bone absorption of low-energy monochromatic radiation. This paper discusses a technique of photon absorptiometry using (125)l as a collimated point source. The technique is simple, with accuracy and precision within 2%.BMC and bone width (W) were measured in the distal radius of 359 normal subjects ranging in age from 5 to 82 years. A "normal" curve of BMC/W with age as the independent variable was then obtained from this population and was constructed for each sex. A positive correlation of BMC/W with height and body weight was found in a group of normal males.A series of patients with osteoporosis or malabsorption, or undergoing hemodialysis or steroid treatment, was then assessed in order to demonstrate changes in BMC/W that may occur secondary to disease or disturbances in calcium metabolism. Many of these patients were found to have a BMC/W below the normal mean value for their age and sex.

Adolescent↗

PubMed1986

Broadband ultrasonic attenuation in the os calcis and single photon absorptiometry in the distal forearm: a comparative study.

The measurement of broadband ultrasonic attenuation (BUA) in the os calcis has been described recently but the method has not been compared with other non-invasive techniques for the assessment of bone mass. We have compared the measurement of BUA in the os calcis with single-photon absorptiometry of the distal forearm in 44 subjects. A highly significant positive correlation was found between these two measurements (r = 0.80, p less than 0.001). Day to day repeatability was assessed for both techniques, with coefficients of variation of 3.9% and 1.4%, respectively, being obtained. Broadband ultrasonic attenuation appears to be a potentially useful bone measurement in the appendicular skeleton.

Adult↗

PubMed1980

Measurement of bone mineral content in human vertebrae and hip by dual photon absorptiometry.

An instrument for clinical measurement of bone mineral content in the axial skeleton was constructed. Components include a modified dual probe scanner, a PDP-11 computer, a 153Gd source, and a NaTI) detector. The results were accurate and highly reproducible, and distinction of osteoporotic women from normal age-matched women was superior to that accomplished with single photon absorptiometry in the radius.

Adult↗

PubMed1989

Quantitative computed tomographic evaluation of femoral bone mineral content in renal osteodystrophy compared with radial photon absorptiometry.

The computed tomography (CT) numbers of cortical bone at the level of 20 cm (CT20) and of spongiosa in the lateral condyle at the level of 2 cm (CT02) from the distal end of the femur were obtained by a quantitative CT method and compared with the bone mineral density of mostly cortical bone within the radius (BMD) by photon absorptiometry. The study included 47 patients with chronic renal failure not dialyzed or induced to regular hemodialysis within 4 weeks of the study (group 1), 28 patients on regular hemodialysis for more than one month (group 2), and ten healthy volunteers (group 3). The measures of bone mineral content (BMC), namely CT20, CT02, and BMD, were compared in terms of their abilities to distinguish members in the various groups. For group 1 and group 3, the greatest variation in BMC was in the difference in CT02, which was primarily a measurement of the BMC of spongiosa. For groups 1 and 2, the greatest variation was in the difference in BMD, which was primarily a measurement of the BMC of cortex. The reproducibility of CT02 was estimated as almost equal to the difference in CT02 values at intervals of 10 months' duration of hemodialysis. The results indicated that CT02 was a useful measurement for evaluating the progress in the early stage of the renal osteodystrophy, and it is recommended that the bone mineral measurement with this QCT method should be performed once or twice a year.

Adult↗

PubMed1986

Precision of dual photon absorptiometry measurements.

One of the important uses of bone absorptiometry is to examine the rate of bone mineral change in order to evaluate therapy and to identify individuals who need therapy. Generally, this involves comparing the difference between two scans obtained months to years apart. This study investigates the precision of dual photon absorptiometry using a human torso phantom, normal subjects, and abnormal patients. These studies showed that bone mineral calculated as g/cm2 was more precise than g/cm. Reanalysis of the same scan by the same individual produced an average error equivalent to that produced by scanning and analyzing the same subject on multiple occasions. Interobserver analysis error was essentially equal to the intraobserver error. In order to obtain maximum precision, care must be taken that the integrated area of a repeat scan is identical to the previous scan. Our findings indicate that to be confident (95%) of a real change between two scans a difference of at least 5.6% must be measured.

Bone and Bones↗

PubMed1977

Cortical thickness measurements and photon absorptiometry for determination of bone quantity.

Reproducibility of estimates of cortical bone quantity in the appendicular skeleton by two methods was studied in healthy individuals and patients undergoing long-term hemodialysis. Repeated measurements of cortical thickness (CT) at the midpoint of the second metacarpal were taken from single radiographs of both hands by two independent observers. Repeated measurements by the same observer were more reproducible and the degree of reproducibility was far greater in healthy subjects than in dialysis patients. Repeated measurements were made of bone mineral content (BMC) and bone width (W) of the distal radius by photon absorptiometry. Repeated BMC/W determinations were highly reproducible in both healthy subjects and dialysis patients. High correlation was found between BMC and cross-sectional cortical area and between both simple cortical thickness and cortical area/width. Thus the photon absorptiometric technique is superior for the serial monitoring of bone quantity, particularly in patients with uremic osteodystrophy, but results obtained by the two methods in group studies should be comparable.

Adult↗

PubMed1989

Validation of single photon absorptiometry in estimating bone mineral mass in rhesus monkey skeletons.

Recent emphasis on age-related morbidity addresses the increasing life expectancy of Western countries. Osteopenia is a multi-factorial process affecting a sizeable number of elderly individuals, with bone fractures producing significant morbidity and related mortality. A non-human primate would be a very useful experimental model for the study of age-related osteopenia, if it could be shown that it is similarly afflicted by age and if non-invasive methods utilized among humans could give a valid estimation of bone mineral content in the animal. Our previous studies utilizing SPA (single-photon absorptiometry) suggest age-related decrease in BMC (bone mineral content) among rhesus macaque skeletons, similar to that observed in humans. The present studies were done in order to further validate the utilization of bone densitometry (SPA) in the rhesus macaque, comparing their BMC and bone density (BD) with the size and weight of their corresponding bones. Both radii and the right femur of 102 adult rhesus monkey skeletons (5 to 23 years old), were obtained from the Caribbean Primate Research Center (CPRC) Skeletal Collection. There were 55 females and 47 males. Bone parameters were obtained using a Norland Digital Bone Densitometer, model 2780 at 2 scanning sites: distal 1/3 of radii and proximal 1/3 of femurs. Bone lengths (cm) and weights (gm) were compared and correlated with densitometric parameters. Excellent correlations were consistently found, with r values 0.74 to 0.96 and p less than 0.0001. Thus it appears that SPA at distal 1/3 radius or proximal 1/3 femur are a valid estimate of total bone mineral mass in rhesus monkeys.

Academies and Institutes↗

PubMed1986

Women at risk for developing osteoporosis: determination by total body neutron activation analysis and photon absorptiometry.

With stepwise multiple logistic regression (MLR), probabilistic classification equations were developed to identify asymptomatic women who are at risk for development of fracture of the spine. Clinically normal women with low TBCa/square root H ratios can be classified as at risk for osteoporosis prior to their developing spinal compression fractures. With receiver operating characteristic (ROC) analysis, it was possible to verify the accuracy of the MLR model to discriminate "normal" women at risk, with high sensitivity and specificity. With the MLR model, discrimination of osteoporotic women (50-59 years) was made correctly for 86.2% of the total osteoporotic subjects with the TBCa data. Similar models were derived from the photon absorptiometry data. From the spinal density (BDs) data, correct classification in the 50-59 year group was 55.6% of the total osteoporosis subjects; from the radius density (BMCr) data, the corresponding value was 31%. The highest probability of identifying osteoporosis in all age categories was, therefore, on the basis of TBCa data. Similar, but less accurate discrimination was achieved with the BDs and BMCr data. These conclusions were confirmed by the application of receiver operating characteristic (ROC) analysis. Correct identification of the population at risk permits the timely and efficient application of therapeutic programs prior to onset of fracture. In a serial study of 104 peri-menopausal women, for example, it was possible to determine the P value for individuals measured annually over a 3-10 year period and thus to predict normal individuals at risk for developing osteoporosis each year.

Age Factors↗

PubMed1988

Bone scanning and photon absorptiometry in metabolic bone disease.

Bone scan imaging with the current bone-seeking radiopharmaceuticals, the technetium-99m labelled diphosphonates, provides a functional display of skeletal metabolism and has dramatically improved our ability to investigate skeletal pathology. While the role of bone scanning in metastatic disease was recognized early, and welcomed by oncologists and other specialists alike, in the field of metabolic bone disease the realization of its potential value has been slower, with perhaps more reluctant acceptance. Nevertheless, the skeleton remains an extremely difficult organ to investigate, and a familiarity with bone scanning should be an essential part of the investigational armamentarium for anyone with an interest in the metabolic bone disorders. The measurement of bone mineral by photon absorptiometry is a relatively new technique, which is rapidly gaining acceptance. The ability to accurately detect and quantify changes in bone mass is potentially of considerable value in the diagnosis and management of osteoporosis. The technique provides us with an extremely important and powerful research tool but, at the present time, its role in clinical practice has yet to be established.

Animals↗

PubMed1989

Quantification of bone mineral content using dual-photon absorptiometry in a normal Japanese population.

The bone mineral content of lumbar spine and/or total body were quantified in 217 healthy Japanese (86 males and 131 females) using a Dichromatic Bone Densitometer (Norland Corp., Model 2600). The bone mineral density of the third lumbar vertebra (L3 BMD) decreased significantly after age 20 in males (r = -0.417, p less than 0.0002), with acceleration of the decrease after age 50 (r = -0.621, p less than 0.00002). A significant correlation was found between L3 BMD and age after age 40 (r = -0.747, p less than 0.0001) in females. L3 BMD correlated with both the body height (r = 0.335, p less than 0.0001) and the body weight (r = 0.340, p less than 0.0001). Total bone mineral content from the second to fourth lumbar vertebrae correlated significantly with total body bone mineral (r = 0.880, p less than 0.00001) in these normal subjects. Lumbar spine bone mineral as measured by dual-photon absorptiometry is lower in Japan than the bone mass in the United States, although not lower than in other parts of the world.

Adolescent↗

PubMed1984

Total body bone mineral in vivo by dual photon absorptiometry. I. Measurement procedures.

A dual photon scanner using a 1 Ci 153Gd source, a NaI detector, traditional electronics and a desktop computer, was constructed. Software for the computation of the total body bone mineral (TBBM) was developed. Non-linear influences such as deadtime due to high count rates, patient scatter and Compton effects were investigated and correction algorithms were introduced in order to obtain exponential attenuation. System precision was measured on a bone-aluminium standard (CV = 2.6%) and system linearity was assessed on aluminium pieces (r = 0.999, SEE = 3.0%). Short-term precision in vivo was tested on 15 healthy subjects scanned twice with a 2-month interval (CV = 2.4%). Long-term reproducibility in vivo was tested on two healthy subjects scanned eight times with 1-month intervals (CV = 1.9% and 3.2%). The influence of patient orientation was investigated on two skeletons. No significant difference was found between anatomical and random orientation. It was concluded that the precision errors were small, therefore making the method applicable not only in cross-sectional studies but also in longitudinal studies designed to investigate the loss or gain of total bone mass in patients suffering from calcium metabolic disorders.

Bone and Bones↗