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PubMed1990

Dual photon absorptiometry using a gamma camera.

The most common technique for bone mineral densitometry is Dual Photon Absorptiometry with a dedicated scanning device. In principle, a gamma camera could be adapted to perform the same function, but little work along these lines has been reported in the literature. Tests made using a standard gamma camera with a 153Gd source at the focus of a magnifying collimator show that satisfactory results can be obtained on water/aluminium phantoms. A calibration is used to help ensure long term precision and stability. Measurements made using the same equipment but 241Am/99mTc sources gave poor results.

Absorptiometry, Photon↗

PubMed1990

Effect of ovariectomy and prednisolone on bone mineral content in rats: evaluation by single photon absorptiometry and radiogrammetry.

The effects of ovariectomy and prednisolone were studied for 9 months in 3-month-old rats on a moderately low calcium diet. Measurements were made by single photon absorptiometry of the femur at cortical and trabecular bone sites. Radiogrammetry was performed at the midshaft of the femur. During growth, body weight, bone size, and bone mineral content (BMC) increased in male rats more than in females. After ovariectomy, body weight increase was more pronounced, but bone mineral increase was lower than in controls. At the distal end of the femur, bone mineral density decreased after 3 months, and at the midshaft of the femur, medullary width increased significantly from 6 months on. Prednisolone in a dose of 0.5 mg/kg/day did not influence BMC. However, prednisolone treatment after ovariectomy induced a more pronounced effect on bone than ovariectomy alone. BMC increase was lower than in ovariectomy, and bone mineral density decreased significantly, especially at the distal end of the femur. After correction for differences in body weight, globally the same results were found. We conclude that (1) the combination of single photon absorptiometry and radiogrammetry allows the evaluation of growth and the effect of ovariectomy and prednisolone treatment in rats; (2) ovariectomy results in bone loss first at the distal end and later in the midshaft of the femur; (3) prednisolone in a dose of 0.5 mg/kg/day alone did not affect bone mass; and (4) prednisolone profoundly enhanced the effects of ovariectomy.

Absorptiometry, Photon↗

PubMed1992

Appendicular and vertebral bone mass in ankylosing spondylitis. A comparison of plain radiographs with single- and dual-photon absorptiometry and with quantitative computed tomography.

OBJECTIVE: We assessed the prevalence, severity, and anatomic distribution of ankylosing spondylitis (AS)-related osteopenia (OP). METHODS: We studied 70 patients (60 males, 10 premenopausal females) with AS (according to the New York criteria) to determine the frequency of OP. Bone mass was measured by plain radiographs of the spine, by single-photon absorptiometry (SPA) of the distal and midshaft of the radius on the nondominant side, by dual-photon absorptiometry (DPA) of the lumbar spine (L2-L4), and by quantitative computed tomography (QCT) of the lumbar spine. RESULTS: SPA values for the radius mass were normal in males and in females, both at the distal and midshaft sites. In contrast, spine radiographs showed diminished density of the vertebral bodies in 69% of the males and 50% of the premenopausal females. Two male patients had had a vertebral compression fracture, and one female patient had had two. DPA values for the spine mass were significantly diminished in the male patients compared with the controls, but not in the female patients. Males with less severe AS also had the largest reduction in lumbar bone mineral content. In patients with more severe disease, lumbar bone mineral content was not statistically different from that in controls. QCT of the lumbar spine performed in 10 patients disclosed low density of the trabecular bone of the vertebral bodies, more so in those with more severe AS and syndesmophyte formation and/or apophyseal joint fusion, which contrasts with the normal values on DPA in these patients. CONCLUSION: Male patients with AS have axial osteopenia. In those who have very severe AS with new bone formation, DPA demonstrates normal values as a result of two opposite trends: central osteopenia (as assessed from QCT) and peripheral new-bone formation, which transforms vertebral bodies into long bones. This could modify the mechanical resistance of the spine and account for the propensity for anteroposterior transvertebral and transdiscal fractures after trauma in AS.

Absorptiometry, Photon↗

PubMed1990

Comparison between radial bone mineral density measured by single photon absorptiometry and histomorphometric bone mass parameters measured on iliac crest biopsies.

Bone mineral density (BMD) measured by single photon absorptiometry (SPA) with a Moolsgard 1100 device on the distal and proximal part of the radius was compared with histomorphometric parameters measured on iliac crest biopsies in 37 patients suffering from various bone disorders. In the whole population, a good correlation was observed between the cancellous bone volume (Cn-BV/TV) measured on iliac crest biopsies and BMD from both the proximal part of the radius (r = 0.76, p less than 0.001) and the distal part of the radius (r = 0.73, p less than 0.001). Significant, although weaker correlations, were also found between the cortical width and the BMD from the distal part (r = 0.37, p less than 0.001) and the proximal part (r = 0.44, p less than 0.001) of the radius. In the 14 untreated osteoporotic patients, only a significant Spearman correlation was observed between the iliac Cn-BV/TV and the proximal radial BMD (r' = 0.69, p less than 0.05). It is thus not clear, whether radial proximal BMD correctly indicates cortical bone density in osteoporotic patients or not. The large internal variability of each of the two investigated methods and the small group of osteoporotic patients might explain the lack of correlation between the two methods in this group.

Absorptiometry, Photon↗

PubMed1990

Dual-photon absorptiometry for determination of bone mineral content in the calcaneus with correction for fat.

A portable dual-photon absorptiometry system for the determination of the bone mineral content BMC in vivo in the calcaneal bone is described. With knowledge of the total thickness of the heel at the measuring point the BMC can be corrected for fat and lean soft tissue. The system is capable of measuring the BMC in the heel bone with a precision of 1.2% in vitro and 1.8% in vivo at an absorbed dose to the skin of 0.2 mSv.

Absorptiometry, Photon↗

PubMed1984

Total body and regional bone mineral by dual-photon absorptiometry in metabolic bone disease.

Dual-photon absorptiometry (153Gd) was used to measure bone mineral of the total body and major anatomical areas. Patients with osteoporosis (male = 11, female = 18) and with renal osteodystrophy (n = 17) were significantly below (20%) normal females (n = 72) and males (n = 13) at most sites. In the osteoporotic patients, but not the renal patients, there was preferential osteopenia of the spine. Bone loss in all anatomical areas became evident after the menopause with an annual loss rate of about 0.7%.

Absorption↗

PubMed1988

Dual photon absorptiometry. The importance of clinical correlation.

Dual photon absorptiometry is a reliable method of assessing bone mineral density. However, distortions of bony architecture, which may not be evident from the low-resolution images provided, can complicate the evaluation and lead to misleading findings. A case is presented which describes the importance of clinical and radiographic correlation.

Aged↗

PubMed1982

Assessment of vertebral osteopenia. Comparison of spinal radiography and dual-photon absorptiometry.

A comparison of radiographic morphology and dual-photon (153Gd) absorptiometry was carried out in 132 women. Films of the lumbar spine were graded for osteopenia, spondylosis, and calcification of the abdominal aorta according to definite morphologic criteria. The radiographic grade of osteopenia and the bone mineral content of the 2nd, 3rd, and 4th lumbar vertebrae showed a highly significant inverse correlation. However, the mineral content at each radiographic grade of osteopenia differed considerably. Disproportionately high levels occurred in patients with spondylosis and severe calcification of the abdominal aorta. Spinal radiography and dual-photon absorptiometry must be regarded as complementary rather than alternative diagnostic procedures in clinical practice.

Absorptiometry, Photon↗

PubMed1990

Adaptation of cancellous bone to overloading in the adult rat: a single photon absorptiometry and histomorphometry study.

Nine-month-old female rats were subjected to right hindlimb immobilization or served as controls for 0, 2, 10, 18, and 26 weeks and were double-labeled with bone markers. The right limb was immobilized against the abdomen and considered unloaded, while the left limb was overloaded during ambulation. Single-photon absorptiometry was performed on intact femur; static and dynamic histomorphometry were performed on 20 microns thick undecalcified frontal sections of the proximal tibial metaphysis. Changes in the continuously overloaded limb was compared to that in both limbs of age-matched control animals. Single-photon absorptiometry detected increases of bone mineral density of +6%, +6%, and +5% in the proximal and +9%, +7%, and +10% in the distal femoral metaphyses after 10, 18, and 26 weeks of continuous overloading. Morphometrically, significant changes occurred in proximal tibial metaphyses compared to age-matched controls: trabecular area increased +41% and +45%, trabecular number increased +31% and +32%, and trabecular separation decreased -30% and -31% after 18 and 26 weeks of overloading. A significant increase in mineral apposition rate (+38%) was found only at 26 weeks of overloading. Insignificant decreases in both eroded and labeled bone surfaces occurred at all time periods. The histomorphometric changes indicated that increased cancellous bone mass was caused by an increase in bone formation activity (i.e., increases in mineral apposition and bone formation rates) and a decrease in remodeling space (i.e., decrease in bone eroded surface). These findings indicate that the adult skeleton can quickly adapt to the increased biomechanical needs by increasing its cancellous bone mass with an adequate structural pattern.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗

PubMed1993

Bone mineral density in patients with noninsulin-dependent diabetes mellitus by dual photon absorptiometry.

Bone mineral density (BMD) in 38 male patients with noninsulin-dependent diabetes mellitus (NIDDM) was measured by dual photon absorptiometry (DPA) using a M & SE OsteoTech 300 scanner. The BMD of the second to fourth lumbar vertebrae was measured and the mean density was presented as g cm-2. The patients were distinguished according to the following three criteria: (1) blood sugar control was good or poor; (2) the duration of diabetes was long or short; (3) renal function was evaluated by effective renal plasma flow (ERPF) as good or poor. The results showed about half the cases of NIDDM had lower BMD. The patients with poor blood sugar control, longer disease duration and poor renal function had lower BMD. However, the difference between any two groups distinguished by the three criteria is not significant. We think that the causes of osteoporosis in patients with NIDDM may not be explained by only a single factor.

Absorptiometry, Photon↗

PubMed1990

[Effect of aging on bone mineral content. Part VII. The evaluation of osteoporosis treatment by the measurement of total body bone mineral content using dual photon absorptiometry].

In order to evaluate the degree of accuracy of measurement of total body bone mineral content (TBBMC) by dual photon absorptiometry (DPA), the TBBMC in four healthy male volunteers were measured serially for 3 to 12 months. In three to six determinations of TBBMC in various stage of radiation source (153-Gd), the coefficients of variation in four subjects were 1.59, 0.74, 1.25 and 1.27%. Thus, the mean CV was 1.22 +/- 0.35% (mean +/- SD). This indicates that the measurement of TBBMC using DPA is an accurate tool for long-term follow up of bone mineral content and up to 1.6% change of TBBMC might be considered to be a significant change in TBBMC. No apparent drift of TBBMC associated with source decay was noticed in the present study. Subsequently, fifteen females with osteoporosis were studied to evaluate the efficacy of certain therapeutic modes. The patients were divided into two groups. Group 1 (n = 10) given 10 to 40 U of elcatonin (eel calcitonin derivative) intramuscularly every week for 3 to 6 months. Group 2 (n = 5) were treated with 0.5 mu/day of oral 1-alpha-OHD3 for 3 to 6 months. The TBBMC of these fifteen patients were followed by DPA (Lunar DP-4). Seven patients out of ten treated with elcatonin (70%) showed significant (up to 1.6% change in TBBMC compared with baseline) increase in TBBMC after 3 to 6 months treatment. The mean percentage change in TBBMC in group 1 was 101.9 +/- 2.7% (mean +/- SD) when the initial TBBMC was taken as 100%.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗

PubMed1995

[In vivo measurement of the mineral content of renal calculi by dual-photon absorptiometry. Correlation with its fragility to extracorporeal shockwave lithotripsy].

After a few years of experience with extracorporeal shock wave lithotripsy (ESWL) and other fragmentation techniques, it has become apparent that stone fragility is a significant clinical distinction that should be taken into consideration when selecting a treatment program. In 30 unselected patients, stone mineral content, density and area were measured in vivo by dual-photon absorptiometry prior to perform ESWL treatment. Stone area determinations showed a median of 4.21 with a range of 0.46 to 49.7 cm2. Stone mineral content (g) and stone density (g/cm2) values were 2.47 and 0.46 with ranges of 0.37 to 13.7 and 0.167 to 1.203 respectively. The number of shocks needed for total fragmentation were 2375 with a range of 1200 to 7800. No correlation could be found between the number of shocks needed for fragmentation and the stone area or density. On the other hand, a strong linear correlation (r = 0.81, p < 0.001) (Fig. 1) could be demonstrated between stone mineral content and the number of shocks needed for fragmentation. Our results support the concept that size alone is not always a suitable criterion for selecting a stone as appropiate for ESWL, since no correlation could be found between stone area and the number of shocks needed for total fragmentation. We were also unable to find any correlation between in vivo stone density measured by dual-photon absorptiometry and the number of shocks required for stone fragmentation. Instead, a strong linear correlation between stone mineral content and its resistance to shock wave fragmentation was found. Therefore, calculation of mineral content appears to be the determinant of the amount of energy required for total fragmentation. Our results strongly suggest that in vivo stone mineral content measurement provides helpful information for predicting the fragmentation prospect of a stone.

Absorptiometry, Photon↗

PubMed1993

The development of juxta-articular osteoporosis after synovectomy of the knee. A prospective study by double photon absorptiometry.

In a prospective study 9 patients, who were going to have a synovectomy for rheumatoid arthritis of the knee, underwent dual photon absorptiometry before, and at intervals after, operation. This determined the degree of juxta-articular osteoporosis quantitatively. The density was compared to a control group with normal knees. The follow up measurements showed an improvement in the juxta-articular bone mineral content after the 6th month. This demonstrates that bone densitometry is an objective indicator of the development of juxta-articular osteoporosis in inflammatory joint disease.

Absorptiometry, Photon↗

PubMed1992

In vivo measurement of bone quality in the horse: estimates of precision for ultrasound velocity measurement and single photon absorptiometry.

The in vivo precision of ultrasound velocity measurement and single photon absorptiometry for the assessment of equine bone quality is discussed. In vivo precisions for ultrasound velocity measurements were less than 0.5 per cent, whereas cortical cross-sectional area, compact bone density and modulus of elasticity were around 1 per cent, and bone mineral content and density were just over 2 per cent. Except for ultrasound velocity, substantial improvements could be achieved by taking the mean of five readings for each measurement. The long-term precision of the techniques was also high, with all precision values being less than 3 per cent. The possible sources of variation in ultrasound velocity measurements were also investigated. The method for combining ultrasonic and photon absorptiometric data for equine bone quality assessment has been proven to be highly accurate and precise. There appears to be no reason why the same principles cannot be applied with equal success to the noninvasive assessment of bone quality in humans.

Absorptiometry, Photon↗

PubMed1989

Axial bone density in rheumatoid arthritis: comparison of dual-energy projection radiography and dual-photon absorptiometry.

The usefulness of dual-energy projection radiography (DEPR) in the evaluation of rheumatoid arthritis was compared with that of dual-photon absorptiometry (DPA). Bone density measurements of the lumbar spine and the proximal femur were obtained with DPA in 75 patients (45 women and 30 men). For comparison, the bone density of the lumbar spine was measured with DEPR in a subset of 52 patients (33 women and 19 men). High correlation was documented between DEPR and DPA measurements of the lumbar spine. No significant relationship between bone density and age was observed, in contrast to the known relationship in healthy subjects regardless of sex, site of measurement, or measurement technique. Bone density values in the spine and the proximal femur were significantly reduced for both sexes as compared with matched normative data. Interlevel variation in lumbar vertebral density as measured with DEPR was not significantly different in patients with rheumatoid arthritis as compared with control subjects. Significant correlation between bone density determination and body weight, as well as duration of menopause, was noted, whereas duration of disease, functional status, and cumulative corticosteroid dose were not predictive. Rheumatoid arthritis did not appear to influence the relationship between DEPR and DPA measurements of the spine, and neither method nor site of measurement exhibited a consistent advantage in discriminating patients with rheumatoid arthritis from healthy control subjects.

Absorptiometry, Photon↗

PubMed1990

Comparative assessment of dual-photon absorptiometry and dual-energy radiography.

Dual-energy bone densitometry can be performed with two types of scanners. The traditional dual-photon absorptiometry (DPA) machines use an isotope source, whereas the newly introduced dual-energy radiography (DER) devices use an incorporated x-ray tube. The authors evaluated the performance of DPA and DER devices at their institution. The short-term precision error in vivo was 1.2% for femoral neck measurements with DER. Long-term precision error in vitro was reduced from 1.30% (DPA) to 0.44% (DER). The scanning time for both spine and hip measurements was reduced from 20-40 minutes to 6-7 minutes. Intraosseous fat sensitivity remained the same, at a level of 12 mg/cm2 apparent decrease of bone mineral density (BMD) per 10% fat by volume change, and for both devices there was no shift in BMD when phantom thickness was increased by 1.5 inches. The correlation of DPA and DER was high: r = .98 for the spine and r = .95 for the femoral neck. Correlation of DPA versus quantitative computed tomography (CT) (r = .83) and DER versus quantitative CT (r = .85) was good. The advent of DER represents a significant advance for the field of bone densitometry.

Absorptiometry, Photon↗

PubMed1991

Relationship between patient exposure and measurement precision in dual-photon absorptiometry of the spine.

Computer simulations and experimental studies were performed to investigate the relationship between patient exposure and measurement precision in dual-photon absorptiometry (DPA). Systems employing 153Gd, K-edge filtered x-rays and dual-kV x-rays were analysed. The results indicate that, except for added exposure due to beam-profile overlap between scan lines, currently available systems are capable of operating at or near the limits of statistical precision per unit of patient exposure. They further indicate that there are no major advantages in exposure requirements for x-ray systems as compared to 153Gd systems.

Absorptiometry, Photon↗

PubMed1992

Bone mineral density in children with Down's syndrome detected by dual photon absorptiometry.

Bone mineral density (BMD) in ten children with Down's syndrome (seven boys, three girls; aged 10-16 years) was measured by dual photon absorptiometry (DPA) using an M&SE OsteoTech 300 scanner. The BMD of the 2nd to 4th lumbar vertebrae was measured and the mean density presented as g cm-2. The BMD of Down's syndrome was compared with the BMD of normal Chinese children of the same age group. The results showed that the BMD in Down's syndrome was significantly lower compared to that found in normal children (P < 0.01). The percentage of decreased BMD is 8.47 +/- 2.69% (mean +/- 1 S.E.M.) in Down's syndrome compared to normal children of the same age group. The distribution curve of BMD against ages in Down's syndrome has a delay of 2.3 +/- 0.5 (mean +/- 1 S.E.M.) years compared to normal children. In our conclusion, the children with Down's syndrome have lower BMD than the normal children of the same age group. The causes of this abnormality may require further study in the future.

Absorptiometry, Photon↗