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PubMed1986

Representativity of regional to total bone mineral in healthy subjects and 'anticonvulsive treated' epileptic patients. Measurements by single and dual photon absorptiometry.

Dual photon (153Gd) and single photon (125I) absorptiometry were used to measure the regional bone mineral content (BMC) and density (BMD), as well as the total body mineral content (TBBM) and density (TBBD), in sixty-nine healthy subjects and in twenty-three epileptics on phenobarbitone. The BMCs (and BMDs) of all regions were significantly correlated to each other and to the TBBM (and TBBD). No difference in the ability to discriminate between the different study groups was found for the various regions, excepting the BMD of the head. The relationship between the forearm BMC and TBBM was highly significant, and identical in the five groups. The relationships between spinal BMC and forearm BMC, and TBBM differed in the five groups. It is concluded that some local measurement may be used as estimates of the total body bone mineral in some groups of patients with minor metabolic bone disease and healthy subjects.

Adolescent↗

PubMed1996

Correlations of dual-energy X-ray absorptiometry, quantitative computed tomography, and single photon absorptiometry with spinal and non-spinal fractures.

Controversy continues as to which method of measuring bone mineral density (BMD) best detects osteoporosis and best correlates with fractures of the spine, hip and elsewhere. To answer these questions the prevalence of fractures was carefully determined among 90 subjects (70 with osteoporosis, 6 with mild primary hyperparathyroidism, 1 with osteomalacia and 13 normals) and simultaneous measurements were made using spinal computed tomography (QCT), spinal anteroposterior (AP) and supine lateral dual X-ray absorptiometry (DXA), femoral neck and total hip DXA, and distal third radial DXA and single photon absorptiometry (SPA). The DXA measurements which had the greatest sensitivity in detecting osteoporosis (defined as a BMD lower than -2.5 SD of peak bone mass at age 30 years) were the supine lateral spine DXA (84%) and femoral neck DXA (75%); less sensitive were the DXA measurements of the distal third of the radius (61%) and AP spine (51%). DXA measurements of the femoral neck and distal third of the radius were more useful than spinal measurements in detecting the osteopenia of mild primary hyperparathyroidism. Vertebral compression fractures (VCF) correlated well with spinal QCT (r = 0.38) and lateral spine DXA (r = -0.41), but poorly with AP spine DXA (r = -0.17) and distal third radial DXA (r = -0.02). Non-spinal fractures correlated best with the distal third radial DXA (r = -0.42). In conclusion, spinal QCT, supine lateral spine DXA and femoral neck DXA are the best BMD methods to screen for osteoporosis, whereas AP spine DXA is a poor screening method in women over 60 years of age. Spinal QCT and lateral spine DXA correlate well with VCFs, whereas correlations of VCFs with AP spine DXA, femoral neck DXA and distal third radial DXA are poor.

Absorptiometry, Photon↗

PubMed1998

Determination of bone mineral density in the third lumbar vertebral body using photon absorptiometry techniques.

Dual-photon absorptiometry and triple-energy X-ray absorptiometry were used to investigate the total bone mineral content and density as well as the trabecular bone mineral density in the third lumbar vertebral body. Both anteroposterior (AP) and lateral (LAT) measurements were performed. By combining the two projections it was found that the mean trabecular bone mineral density for all 202 subjects included in the study was 52% (SD +/- 20%) of the total bone mineral density in the third lumbar vertebral body. The mean trabecular bone mineral density as a fraction of the total vertebral body bone mineral density decreased as a function of age. The relative annual change in this fraction differed between males and females. It was also found that neither trabecular nor total bone mineral density differed significantly between male and female subjects aged 25-35 years, and bone mineral density (BMD), expressed in g/cm3, showed no correlation to subject height, body weight or body mass index (BMI). Male and female individuals showed different rates of change of trabecular bone mineral density with age.

Absorptiometry, Photon↗

PubMed1992

[Lumbar inter-apophyseal arthrosis and bone mineral content: prospective study versus controls with dual photonic absorptiometry and tomodensitometry].

Dual photon absorptiometry (DPA) is a non invasive and repeatable technique to measure vertebral bone mineral content (BMC). This method can be altered, in frontal incidence, by superposition of abnormal calcifications as calcified aorta or interapophyseal arthrosis. The authors studied nineteen females with lumbar apophyseal arthrosis compared with twenty one controls matched by age. Bone densitometry was performed by Am-Ba DPA and monoenergetic computerised tomodensitometry (CT) from L2 to L4. Arthrosis was studied by standard X ray radiographs and CT. Our results showed that inter-apophyseal arthrosis does increase BMC determined by DPA, especially when expressed as linear BMC (g/cm). The body mass index [weight (kg)/size (m2)] also increased these measures by DPA. CT results were, at the opposite, not influenced by osteo-arthrosis nor body mass index. Detailed analysis of DPA pictures allowed to recognize most of patients with osteo-arthrosis and to correct their results by using adjacent vertebral measures (L1) or abandoning pictures of unusual aspect. The authors mentionned necessity to match populations for age and body mass index and to include L1 in routine vertebral bone mineral content determination. By this way they supposed that osteo-arthrosis may not alter lumbar BMC measured with DPA technique.

Absorptiometry, Photon↗

PubMed1990

Direct measurement of abdominal fat by dual photon absorptiometry.

We have assessed photon absorptiometry as a new technique for direct measurement of the abdominal fat percentage (AF%). The accuracy of the method was assessed in vitro with phantoms consisting of ox muscle, lard, and a mixture of both. The results showed good linearity (r = 0.999). The in vitro reproducibility and the in vivo reproducibility were s.d. = 2.0 and s.d. = 2.8 (AF%), respectively. The AF% was measured in 148 healthy post-menopausal women and found to correlate with other measurements of fatness, such as total body fat per cent (r = 0.82, P less than 0.001), body mass index (r = 0.79, P less than 0.001) and the ratio of waist-to-hip circumference (r = 0.59, P less than 0.001). The waist-to-hip ratio, an important predictor of cardiovascular disease, was more tightly correlated with AF% than with body mass index. We conclude that this method may be a useful new research tool for direct measurements of abdominal fat, a possible cardiovascular risk factor.

Abdomen↗

PubMed1988

Bone mineral content in the senescent rat femur: an assessment using single photon absorptiometry.

The single photon absorptiometry technique was evaluated for measuring bone mineral content (BMC) of the excised femurs of the rat, and the system was used to examine the changes in cortical and trabecular bone from young adult (6 mo), mature adult (12 mo), and senescent (24 mo) male and female animals. BMC of the femur midshaft, representing cortical bone, apparently increased progressively with advancing age. The width of the femur at the scan site also increased with age. Normalizing the midshaft BMC by width partially compensated for the age-associated increase. However, when bone mineral values were normalized by the cortical area at the scan site, to take into account the geometric differences in the femurs of different aged animals, maximum bone densities were found in the mature adult and these values decreased slightly in the femurs from senescent rats. In contrast, the BMC of the femur distal metaphysis, representing trabecular bone, decreased markedly in the aged rat. The loss of trabecular bone was also evident from morphological examination of the distal metaphysis. These findings indicated that bone mineral loss with age was site specific in the rat femur. These studies provided additional evidence that the rat might serve as a useful animal model for specific experiments related to the pathogenesis of age-associated osteopenia.

Aging↗

PubMed1989

Correction of the effects of source, source strength, and soft-tissue thickness on spine dual-photon absorptiometry measurements.

Dual photon absorptiometry measurements of the spine are subject to drift associated with source, source strength, and truncal thickness. This study was conducted to determine the extent to which this drift in bone mineral density (BMD) measurements can be improved by analysis of scans with a new software version, 08C, and by applying external standard or phantom corrections to scans analyzed with the older version, 08B. A phantom, consisting of human lumbar vertebrae embedded in acrylic, and five clear acrylic plates to simulate a soft-tissue thickness range of 15.2-27.9 cm, was measured on a Lunar Radiation Corp DP3 scanner over the life of a 153-gadolinium (Gd) source and scans analyzed with software versions 08B and 08C. Phantom BMD was lower with 08C at both high [0.012 +/- 0.002 (SEM) g/cm2, P less than 0.001] and low (0.027 +/- 0.003 g/cm2, P less than 0.001) count rates than with 08B. Phantom BMD of scans analyzed with 08B increased with increasing source age and the source strength-related increment increased significantly as acrylic thickness increased (P = 0.014). When the same scans were analyzed with 08C, the thickness-related effect was corrected whereas a small (0.011 g/cm2/year) source-strength effect persisted. The effects of source strength and truncal thickness on BMD were also evaluated in 40 humans scanned at two detector collimations to vary count rate. With 08B, mean BMD was 1% greater when measured with 8 than with 13 mm collimation (mean difference 0.011 +/- 0.003 g/cm2, P = 0.001), whereas the version 08C, mean BMD was the same at the two collimations.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1987

The symmetry of hip bone mineral density. A dual photon absorptiometry approach.

Dual photon absorptiometry studies were performed on the hips of 23 patients to determine whether bone mineral density values obtained from one hip were indicative of the values in the contralateral hip of the ambulatory patient. The femoral neck, trochanteric, and Ward's triangle areas of both hips were analyzed. There were no significant differences between the right and left hip bone mineral density measurements in any of these three areas. Since the right and left hip readings were highly correlated, either hip may be used to evaluate osseous status.

Adult↗

PubMed1989

Normal and abnormal features of the lumbar spine observed in dual photon absorptiometry scans.

Dual photon absorptiometry (DPA) is an extensively used technique for measuring the density of the lumbar spine. The presence of vertebral and extra-vertebral pathologies can lead to increased scatter of data and artifactual bias when constructing diagnostic reference value curves. The bone density of patients with such abnormalities cannot be compared with those of normals because it will appear artificially high. Furthermore, little effort has been made to identify and evaluate spinal abnormalities using the pictograms produced in this method. We have analyzed 60 DPA scans for morphologic changes, using x-rays for comparison, and have found practically complete concurrence between these two radiologic methods on features, though only the former is capable of accurately quantifying bone density. Examples of DPA presentation of anatomical morphology are shown to aid the user in interpreting DPA findings.

Adult↗

PubMedDate not supplied

Diagnostic approach to osteoporosis and spondyloarthrosis in post-menopausal women by total body dual-photon absorptiometry.

Dual-photon absorptiometry of total body (153 Gd with photopeaks at 44 and 100 keV) enables bone mineral content of the entire skeleton and its major anatomical areas to be quantitated. Total body bone mineral (TBBM), total body density (TBD), bone mineral content and bone density of spine and lumbar-spine were measured in 97 women with post-menopausal osteoporosis, 33 females with spondyloarthrosis and in 19 females with spondyloarthrosis associated with osteoporosis. Seventy-nine females of similar age made up the normal control group. TBBM and TBD proved to be significantly lower in post-menopausal osteoporotic women compared to age-matched normal females: bone loss was particularly evident in spine measurements. In spondyloarthrosis patients TBBM and TBD fell within the normal range and both spine bone density and spine bone mineral did not differ from normals. TBD, TBBM, spine density and spine mineral in females with disuse osteoporosis associated with spondyloarthrosis were significantly lower in comparison with normals and higher with respect to post-menopausal osteoporotic women. Total body absorptiometry represents a valuable method in the differential diagnosis of post-menopausal osteoporosis, spondyloarthrosis and the disuse osteoporosis associated with spondyloarthrosis.

Bone and Bones↗

PubMed1986

Measurement of bone mineral content in the human fetus by photon absorptiometry.

A photon absorptiometer designed to measure the bone mineral content (BMC) of the radius and ulna in premature or term babies was used to examine 34 forearm specimens obtained from 25 male and 9 female babies dying before or up to 13 weeks after birth. Gestational age, foot and crown-heel lengths and birth weight were recorded. Radiographic measurements showed that the midshaft of the radius can be located with a positioning error of +/- 1.28 mm (+/- 2 S.E.E.) from the distance between the distal ulnar styloid process and proximal tip of the olecranon, both of which can be palpated in vivo. Scanning at 5 sites showed that effects of positioning errors on BMC measurements are least at the midshaft site. Subsequent measurements of the ash weight of sections of the radius and ulna, centred on the midshaft of the radius, showed that ash weight/unit length can be estimated with a standard error 2.99 mg/cm from scan data.

Birth Weight↗

PubMed1998

Evaluation of peripheral dual energy X-ray absorptiometry: comparison with single photon absorptiometry of the forearm and dual energy X-ray absorptiometry of the spine or femur.

An evaluation of the Osteoscan peripheral dual energy X-ray absorptiometer (pDXA) was carried out to compare its performance with those of a single photon absorptiometer (SPA) (Molsgaard Medical ND1100A) and a dual energy X-ray absorptiometer (DXA) (Lunar DPX alpha) of the spine or femur. In 57 patients, correlation between bone mineral content (BMC) of the forearm at the ultradistal (UD) site by pDXA and by SPA was high (r = 0.94). Comparisons were also made with spine and femur bone mineral density (BMD) DXA measurements. The correlation of z-scores of UD BMD with z-scores for lumbar spine L2-L4 was r = 0.63 (n = 73 patients); and with z-scores for neck of femur was r = 0.72 (n = 33). With the Osteoscan the measurement error coefficient of variation in vivo was 2.6% for BMC, 1.8% for BMD at the ultradistal site; 2.1% for BMC and 1.9% for BMD at the mid-distal site. Repeat measurements were made of the European forearm phantom; precision for SPA was slightly better than either pDXA or Lunar DXA. The Osteoscan has the potential for a rapid throughput of patients and is not affected by calcification and degenerative changes that can corrupt DXA measurements on the anteroposterior spine in older women.

Absorptiometry, Photon↗

PubMed1995

Single X-ray absorptiometry: performance characteristics and comparison with single photon absorptiometry.

The aim of the present study was to evaluate a new device for measurement of forearm bone mass using the technique of single X-ray absorptiometry (SXA, DTX-100; Osteometer A/S, Rødovre, Denmark), and to compare the performance with the more traditional single photon absorptiometry (SPA, DT 100; Osteometer A/S, Rødovre, Denmark). The SPA phantom measurements showed a coefficient of variation of 0.43% and 0.42% for bone mineral content (BMC) and bone mineral density (BMD), respectively (39 months including seven source changes). The SXA precision errors were slightly lower with values of 0.30% and 0.30%, respectively. The patient measurements showed SPA coefficients of variation of 0.85% and 0.99% (BMC and BMD) and SXA coefficients of variation of 0.56% and 0.83%, respectively. The correlation between SPA and SXA values performed in 377 individuals yielded r values of 0.99 and 0.98 for BMC and BMD, respectively. The correlations between SXA measurements of the dominant and non-dominant forearm yielded an r-value of 0.95, with a slope of 0.949 (p < 0.001) and an intercept of 0.204 (p < 0.05). The non-dominant forearm thus had approximately 3% lower BMC than the dominant (the same was true for BMD). Correlations to spine and femur ranged from r = 0.48 to r = 0.75. In conclusion, the new single X-ray absorptiometry forearm bone densitometer described in this paper has performance characteristics which allows it to be used both for diagnostic purposes and for the follow-up of treatment.

Absorptiometry, Photon↗

PubMed1997

The accuracy of peripheral skeletal assessment at the radius in estimating femoral bone density as measured by dual-energy X-ray absorptiometry: a comparative study of single-photon absorptiometry and computed tomography.

OBJECTIVES: One of the latest developments in bone densitometry is peripheral quantitative computed tomography (pQCT), a method which allows the separate determination of cortical and trabecular bone mineral density (BMD) in the peripheral skeleton. This study was designed to compare the relative abilities of single-photon absorptiometry (SPA) and pQCT to reflect BMD of the proximal femur as measured by dual-energy X-ray absorptiometry (DXA), an established predictor of osteoporotic hip fracture risk. DESIGN: Cross-sectional study. SUBJECTS: A well-defined community-based sample of 129 skeletally healthy women aged 70-87 years. MEASUREMENTS: Radial BMD by SPA and pQCT and femoral BMD by DXA. Univariate and multivariate regression analyses were performed relating the DXA measurements at the femoral neck and the trochanteric region with the values of SPA and pQCT. RESULTS: Approximately 38% of the variance in femoral neck BMD could be explained by BMD of the midradius assessed by SPA, in contrast to only 18-27% by pQCT. At the trochanter, 32% of BMD could be predicted by SPA as compared to 19-26% by pQCT. Moreover, according to multiple regression, prediction of femoral BMD by SPA was not enhanced by performing pQCT. CONCLUSIONS: Radial pQCT has little value as a screening tool to identify elderly women with low femoral BMD. Additional research is needed to determine whether or not pQCT will enhance fracture prediction beyond that obtainable from a density measurement by SPA.

Absorptiometry, Photon↗

PubMed1990

Body composition by photon absorptiometry.

Whole-body dual photon measurements of body composition were made in 9 controls, 15 athletes and 5 patients with eating disorders. Measurements of lean body mass, mineral mass and fat mass were accurate. Lean body mass and fat mass were measured with reliabilities of about 0.8 kg while for total body bone mineral mass, the reliability was about 60 g. Women had a smaller lean body mass and a greater fat mass than men. Women with eating disorders had the same body composition as males. Measurements of body composition by dual photon absorptiometry are safe and reliable.

Absorptiometry, Photon↗

PubMed1988

Single photon absorptiometry imaging as a screening method for diminished dual photon density measures.

Scanning of the new 5-mm distal-radius site and the mid-radius (33% site) was performed using single photon absorptiometry (SPA) and of the L2-L4 region of the spine using dual photon absorptiometry (DPA) in a group of healthy women (age range 36-66 yr) in order to develop parameters to enable SPA to be used to screen for low DPA measures. The study data were analyzed as follows: 1. Women were classified as either 'intact' or 'post pelvic surgery' and the data for the two groups were separated. 2. Each SPA measurement was scrutinized and the one which produced the lowest score (% young normal [YN]) was entered for data analysis and graphing. The application of these two analytical discriminators represents a new approach in the biomedical literature. The findings were as follows: 1. When women were separated according to whether they were intact or had undergone pelvic surgery, the threshold value for screening using radius measures among intact women was set at 80% YN. 2. The necessary threshold value for the pelvic-surgery group needed to be set higher, at 93% YN. 3. If either the distal density or the mid-shaft density was below its threshold level, DPA was indicated. 4. At these threshold levels, no women with diminished spinal density (less than 83% YN) were omitted from screening procedure. We conclude that by refining our evaluation of each healthy woman according to her pelvic physiology status (intact or post-surgery) and considering whether either of the two SPA measures is below the threshold value, we will be able to screen for diminished DPA density and thereby eliminate a significant number of expensive but uninformative DPA readings.

Adult↗

PubMed1992

Dual-energy x-ray absorptiometry of the forearm: reproducibility and correlation with single-photon absorptiometry.

Although single-photon absorptiometry (SPA) has been the predominant tool used to assess bone mineral density (BMD) in the forearm, the development of dual-energy x-ray absorptiometry (DEXA) provides the benefits of greater source stability, reduced scanning time, and improved image resolution compared to SPA. In the present study we used the DEXA bone densitometer (Hologic, Inc., Waltham, MA) to (1) measure BMD in the one-third radius and ultradistal radius; (2) examine the reproducibility of these BMD measurements; and (3) compare the BMD at the one-third radius with SPA (SP2, Lunar Corp., Madison, WI). In 65 normal women (ages 22-74 years) we examined changes in the forearm DEXA BMD with age, revealing significant quadratic regression equations. The reproducibility of DEXA BMD (mean +/- SEM) in 7 normal subjects aged 22-50 years is 0.85 +/- 0.16% for the predominantly cortical one-third radius site and 0.97 +/- 0.15% for the more trabecular ultradistal site. The regression relationship between DEXA and SPA of the one-third radius in 26 subjects (ages 22-68 years) is DEXA BMD = 0.105 + 0.826 (SPA BMD); R = 0.97, R2 = 0.94, p less than 0.0001. Bone densitometry of the forearm using DEXA may be performed relatively rapidly, providing reproducibility and image resolution that are generally superior to those observed with SPA.

Absorptiometry, Photon↗

PubMed1994

Total body mineral mass measured with dual photon absorptiometry in healthy children.

Using dual photon absorptiometry, bone mineral content (BMC) and bone mineral density (BMD) of the total body and the lumbar spine were assessed in 97 healthy, Caucasian children aged 3-14 years. Excellent correlations were found between BMC and BMD on the one hand and age, body height and body weight on the other. No differences were found between boys and girls. There was a strong correlation between lumbar spine measurement as compared to those of the total body. Regression equations for total body and the different parts of the skeleton were calculated with either BMC or BMD as the dependent variable, and age, body height and body weight as independent variables. High variation coefficients were obtained in these multiple regressions, except for the head. For total body BMC and total body BMD, growth charts were constructed using Tanner and Whitehouse data on body height and body height and body weight. Conclusions. The increase in total body mineral content is an important feature of normal growth. Normal data for BMC and BMD in childhood are essential for bone mineralisation abnormalities in paediatric patients.

Absorptiometry, Photon↗