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At least 19 recordsLinked to original sources
PubMedDate not supplied

Vertebral and peripheral bone mineral content by photon absorptiometry.

Dual photon absorptiometry with 153Gd was used to determine the bone mineral content of the lumbar spine of 46 subjects. The bone mineral content of the radius and ulna were measured on these same subjects using single photon absorptiometry. The bone mineral content at the peripheral sites was not a very accurate indicator of absolute bone mineral content in the spine. However, the rate of bone loss with age was greater in the peripheral bones than in the spine. Measurement sites on the appendicular skeleton may provide a more sensitive indication of age changes in bone mineral content throughout the skeleton than would sites on the axial skeleton.

Absorption↗
PubMed1992

Pitfalls of bone mineral density evaluation by dual-photon absorptiometry.

Material absorbing photons aligned with the lumbar vertebrae can create falsely elevated measurements of bone mineral density during dual-photon absorptiometry. Three cases illustrating this phenomenon are presented. Although bone mineral density was overestimated in each case, calculated fracture risk was normal in two cases and greatly increased in the third. Photon-absorbing material can create overestimates of bone mineral density during dual-photon absorptiometry, even when a greatly increased fracture risk is computed.

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↗
PubMed1992

Time related bias in longitudinal studies using dual photon absorptiometry.

Examining the bone mineral density (BMD's) slope of patients regularly followed in our department, we observed recently that the group of patients who had their last BMD during the last 6 months of 1989, had a different slope than patients who had their last BMD during the following 6 months. In order to investigate if a small time-related bias of measurement, unsuspected by the former quality control investigations, could exist, we performed the following analyses. A regression equation between BMD and time was calculated and a slope was obtained for 95 women who had been followed for at least 3 yr and had had at least 3 BMD measurements during that time. The women were divided in 3 groups according to when the last BMD measurement had been performed (July-December 1989, January-June 1990 or July-December 1990). The slopes of the 3 groups of patients were compared. For each value of BMD of every patient, a predicted BMD (BMDp) was calculated using the regression equation and the relative difference (RD) between BMDp and BMD was calculated and analysed in relation to time. There was a significant difference (p < 0.05) between the slopes of patients in relation to the time when the last BMD had been measured. Significant fluctuations (p < 0.001) in RD were observed in relation to time. These RD variations suggested the existence of a time-related error. The presence of this error is also substantiated by the fact that a parallelism existed between the curve of the RD variations and the curve of the mean values of BMD of all patients referred to our department, calculated per period of 4 months. Although the fluctuation of the latter curve was not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1992

[Evaluation of the bone mass by dual-photon absorptiometry in children under prolonged anticonvulsant therapy].

We have evaluated, in a prospective study, the total and per unit area mass, measured in lumbar spine by Dual Photo-absorptiometry, in a group of 62 children on long-term anticonvulsant treatment. A second group of 58 normal children was used as a control. The total and per unit area bone mass increased with age, weight, height and bone maturity in all of the children studied. There were no significant differences found between the two groups. Children on multi-therapy and that were over six years of age showed statistically significantly less bone mass per area when compared th the control group (p less than 0.01). Phenobarbital, Carbamazepine and Valproic acid in monotherapy did not statistically diminish bone mass. Of these anticonvulsants, Phenobarbital was responsible for the most statistically significant decline in bone mass per area (p = 0.027). After six year of treatment, whether on mono-therapy or on poly-therapy, bone mass was lower with respect to the control series, although this was not statistically significant.

Absorptiometry, Photon↗
PubMed1992

[Dual photon absorptiometry in algodystrophy].

Biphotonic absorptiometry has begun to demonstrate its usefulness in the field of osteoporosis. In algodystrophy, the radiology and the degree of isotopic fixation suggest a bone disorder, although both techniques are unable to objectively quantify it. Biphotonic absorption is an scanning technique which allows the quantification of bone demineralization in the segment affected by algodystrophy and its evolutive follow-up.

Absorptiometry, Photon↗
PubMedDate not supplied

Reference values for radial bone width and mineral content using single photon absorptiometry in healthy children aged 4 to 10 years.

Bone width and mineral content were measured in 420 healthy Cambridge children aged 4 to 10 years using single photon absorptiometry. The results are expressed first in the form of standard centile charts, with additional prediction charts which provide body-size-adjusted estimates for the measurements, and interpretation centiles for comparing these estimates with the actual measurements. The values obtained are similar to those reported for American children aged five to six years after adjusting for body-size differences. We suggest that appropriate application of these prediction charts will facilitate the use of single photon absorptiometry in monitoring and treating children who have disorders of bone growth and mineralization.

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↗
PubMed1992

Total and regional bone mineral density by dual photon absorptiometry in patients on maintenance hemodialysis.

To evaluate bone loss in renal osteodystrophy, we measured total and regional (head, trunk, pelvis, leg and arm) bone mineral density (BMD) by dual photon absorptiometry in 72 patients on maintenance hemodialysis (HD). We also examined the validity of serum carboxy-terminal parathyroid hormone (C-PTH) and intact-PTH as an indicator of secondary hyperparathyroidism. Total BMD correlated inversely with age in female patients (r = -0.57, p less than 0.01), but not in male patients. Female patients older than 50 years were omitted from analysis to exclude the effect of menopause on bone. Among clinical and biochemical parameters, only trunk BMD correlated inversely with the duration of HD (r = -0.26, p less than 0.05). Head, trunk and total BMD correlated inversely with serum alkaline phosphatase, C-PTH and intact-PTH, while pelvis BMD did not. Leg and arm BMD also correlated inversely with serum intact-PTH, but not with serum C-PTH. The serum level of C-PTH correlated positively with the duration of HD (r = 0.40, p less than 0.005), while intact-PTH did not. As compared with 18 control male volunteers aged 25-42 years, trunk, pelvis, leg, arm and total BMD were significantly lower in male patients on HD aged 22-49 years, whereas head BMD did not differ significantly between the two groups. The percent decrease of BMD was most prominent in the trunk (-19.6%, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1977

Bone mineral status measured by direct photon absorptiometry in childhood renal disease.

Bone width (BW), bone mineral content (BMC), and their ration (BMC/BW ratio) were measured in renal patients using direct photon absorptiometry. Serial measurements were made on the radius and ulna in 74 children with renal diseases. Values were compared to age-, sex-, height-, and weight-matched controls. The SD from the mean in normal subjects is +/- 10%. Significant demineralization (greater than -2 SD) was found in 42% of all patients and in 75% with tubulointerstitial disease. Twelve patients with nephrotic syndrome and two with systemic lupus erythematosus, all of whom were receiving prednisone therapy and had a serum creatinine level less than 1.0 mg/dl, and three treated with anticonvulsants had significant demineralization. Severe demineralization (greater than -3 SD) was found in four rachitic patients with tubulointerstitial disease. Normal mineralization was present in 32 patients with various primary glomerular diseases, seven of whom had a serum creatinine level greater than 1.5 mg/dl. BMC declined with daily prednisone therapy but increased with alternate-day dosage in seven patients. This study suggests that demineralization is more common in patients with tubulointerstitial disease and in patients with primary glomerular disease who are receiving prednisone (16 patients) or anticonvulsants. Photon absorptiometry appeared more useful than conventional radiographic evaluation in assessing skeletal involvement in childhood renal disease.

Adolescent↗
PubMed1977

[The use of photon absorptiometry in renal osteodystrophy (author's transl)].

In 58 patients with end-stage renal failure before commencement of regular hemodialyses treatment (RTD) and 58 patients under RTD bone mineral content (BMC) was determined by the use of the photon absorptiometry. Further the effect of a treatment with bitamin D3 and 5,6-trans-25-OH-vitamin D3 on BMC was studied. There existed a negative correlation between the duration of chronic renal failure or of RDT as well as of the serum parathyroid hormone level to BMC. No correlation was found between BMC and serum calcium level. During a 14 months-course treatment with vitamin D3 or 5,6-trans-25-OH-vitamin D3 BMC increased. The method of photon absorptiometry presented itself as an easy and well reproducible technique for routine examinations.

Adolescent↗
PubMed1992

[Bone risk of hormone-suppressing therapy in differentiated thyroid epithelioma. Study by dual photon absorptiometry].

A decreased bone mineral density is a well known complication of thyrotoxicosis. If bone is also adversely affected by a subclinical hyperthyroidism is still debated. Such a situation is deliberately induced for treatment of thyroid differentiated carcinoma. We compared bone mineral measurements in case of thyroid carcinoma exposed to prolonged suppressive hormonal treatment (288 patient year, LT3 in 87%) and in age and weight matched controls. We did not find any difference in both sexes between the two populations in term of fracture rate and vertebral mineral density measured by dual photon absorptiometry, nor any influence of gonadal status in women.

Absorptiometry, Photon↗
PubMed1978

Combined cortical thickness and bone density determination by photon absorptiometry.

Bone cortical thickness and density were measured in rat femurs in vitro by a photon absorptiometry technique. A scan perpendicular to the long bone axis using photons from highly collimated 109Cd or 125I sources yielded the bone wall thickness and attenuation at mid-shaft. A second scan after the bone was rotated axially 90 degrees was taken to measure the wall or shaft thickness identically responsible for the mid-shaft attenuation of the first scan. The mid-shaft attenuation of the second scan was due to the bone thickness derived from the first scan; thus two complementary measurements are derived by this technique. The bone density is then directly calculated with an estimated accuracy of 10% (coefficient of variation) using empirically determined mass attenuation coefficients. Measurements of mass attenuation coefficients of ashed and dried samples were compared with calculated coefficients for estimated bone composition. Results indicate that the mass attenuation coefficient for bone in vivo can be well estimated such that bone density can be accurately derived from this technique.

Animals↗
PubMed1976

Bone demineralization in renal failure: a longitudinal study of the distal femur using photon absorptiometry.

The bone mineral content (BMC) of the lower end of the femur was measured by photon absorptiometry in 87 patients with chronic renal failure. The gamma-ray photon source was Am241. Serial measurements were obtained for up to two years. The mean BMC of the adult patients, comprising: 18 pre-dialysis (CRF), 41 chronic haemodialysis (CHD) and 19 renal transplant (RT) patients were all significantly lower than controls with the exception of the male CRF group. Two adults and one child on chronic haemodialysis showed a significant rate of bone loss (less than 2% per year). In one of these adults the addition of daily oral 1 alpha hydroxycholecalciferol was associated with no further reduction in BMC. Two children and one adult on chronic haemodialysis showed a significant rate of increase in BMC (less than 2% per year). This adult had had a tendency to loss of BMC on standard CHD treatment but after receiving parenteral 1,25 dihydroxycholecalciferol three times weekly showed a significant rate of loss of BMC on serial measurement. Two adults and one child with CRF had a significant rate of increase in BMC on standard treatment.

Adolescent↗
PubMed1979

Demineralization in cystic fibrosis detected by direct photon absorptiometry.

Bone mineral content, bone width, and their ratio were measured in patients with cystic fibrosis (CF) using monoenergetic photon absorptiometry. Serial measurements of the radius and ulna were made in 27 patients with CF and were compared with 968 age-matched controls. Demineralization was found in 37% of the boys and 63% of the girls. Patients under age 10 years had normal bone mineral content and nine of 15 patients aged 13 or older were demineralized (P less than .01). Demineralization correlated with the extent of weight reduction in patients (P less than .001). Patients most likely to be demineralized were adolescent girls. To our knowledge, this is the first report of bone mineral status of children with CF, and the results indicate that a sizable proportion of these patients may be demineralized without overt rickets.

Adolescent↗
PubMed1975

Bone mineral content in the forearm measured by photon absorptiometry. Principles and reliability.

A method for estimating total bone calcium is reported. The method is based on two-dimensional scanning photon absorptiometry on the distal part of the forearm. The following factors are investigated: precision of measurements on standards and human subjects; linearity; the effect of varying bone orientation; amount of fat and soft tissue; and the relation between weight and content of calcium and phosphate. The results show that the method is eminently suitable for rapid, easy, and atraumatic measurement of local bone calcium in vivo.

Adult↗
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↗