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PubMedDate not supplied

[Correlation between serum glutathione reductases and bone densitometry values].

Free radicals, because of their marked chemical activity, have often been found to be involved in many human diseases. Enzymatic antioxidant systems, namely glutathione-reductase, present both in red blood cells and in serum, have been demonstrated to play a key role as free radicals scavengers. The present work has been carried out in order to evaluate the possible role played by free radicals in the demineralization process of the bone matrix. Glutathione-reductase activity, assayed by a slightly modified Horn's method, was related to bone density measurements. All the subjects with reduced densitometric values showed reduced glutathione-reductase levels. Our results seem to support the hypothesis of a strict relationship between low activity of antioxidant systems and demineralization process of the bone, in consequence of enhanced free radical levels.

Aged↗
PubMed1991

[Biphoton bone densitometry in hyperthyroidism caused by Basedow's disease].

Bone mass and bone exchange were studied in 10 post menopausal females (age 36 +/- 9) with hyperthyroidism due to Graves disease dating from over 6 months. Biphoton osteodensitometry of the lumbar spine and hips, calcium intake, hematocrit, hemoglobin and 24 hr urinary calcium excretion were determined in each patient and compared to a control group. Hyperthyroid patients had a lower calcium intake, and evidence of higher bone turnover. However, bone density was not different from control. There was a strong correlation of bone density with serum calcium (r 0.72) and T3 levels (r 0.68). Thus, untreated hyperthyroidism associated to Graves disease does not lead to decreased bone mass in a 6 month period.

Absorptiometry, Photon↗
PubMed1991

[Dual-photon densitometry of the lumbar spine. Further experience and findings].

The authors submit further experience with two-photon absorption measurement of the mineral content of the lumbar spine using a NOVO/Lab BMC 22a (Denmark) apparatus. 1. The authors discuss the problem of evaluation of results in postmenopausal women. For the basic evaluation the authors use the range +/- 2 s of "normal" values classified by decades; another suitable guide to the interpretation could be extrapolation of the lower range of the regression zone in recorded in premenopausal women to higher age groups. 2. The histogram of frequencies of normal values in women in g.cm-2 has two peaks corresponding to the group of premenopausal women and the group of postmenopausal women. 3. Of 573 examined patients with osteoporosis 295, i. e. 51.5%, cannot be reliably evaluated or cannot be evaluated at all (as a rule because of changes of the spine). Of 49 results obtained in men with osteoporosis 34.7% are within the normal range, of 229 results obtained in women with osteoporosis 47.2% are within the normal range. The hitherto assembled experience is consistent with the view that the method is useful and invaluable in particular for the long-term follow up of patients.

Absorptiometry, Photon↗
PubMed1990

[Bone mass in males. A comparison between dual-photon densitometry of the lumbar spine and the whole body].

In order to evaluate the validity of a new method for measuring the whole body mineral content in diagnosing senile osteoporosis we studied 3 groups of male subjects: the first one composed by 40 young healthy subjects (mean age 24.7 years), the second composed by 40 normal patients (mean age 51.3 years); the 3rd group consisted of 26 elderly patients affected with typical osteoporotic fractures (mean age 77 years). All of them underwent a measurement of the spine as well as whole body mineral content performed with a dual photon absorptiometer. The measurements showed a decreasing in mineral content in the second versus the first group but a high correlation coefficient between spine and WB measurements characterized both groups; a striking decrease of it (r = 0.22) was found in the 3rd group. The relative unreliability of the spine measurement in elderly is probably due to the age-linked anatomical alteration. We therefore conclude that WB measurement must be considered the method of choice for the detection of senile osteoporosis.

Absorptiometry, Photon↗
PubMedDate not supplied

[Digital processing and densitometry of tomograms in central lung cancer].

Additional information on an x-ray picture of peribronchial changes in tumorous and non-tumorous lesions of the lungs were obtained in 54 patients (40 with bronchogenic, mostly central cancer and 14 with chronic inflammatory diseases) in order to study roentgenological symptomatology before and after computerized processing of tomographic images using a method of linear filtration. Image processing with the measurement of densitometric indicators provides additional information for the estimation of bronchial affection by tumor infiltration. The same method can be of value for the detection of early signs of lung cancer in patients with peribronchial changes of obscure etiology.

Humans↗
PubMed1990

[The history and present status of bone densitometry].

Measurement of bone mass would be playing a major role in the field of research and clinical decision making of metabolic bone diseases, especially osteoporosis. As the magnitude of bone loss and the response to treatment are different from site to site throughout the entire skeleton, it is important to know which bone should be measured by which technique. Although values of BMD at various sites in the skeleton are significantly correlated, measurement at the actual site of fracture should be the most accurate way to predict fracture risk. New techniques and machines are now still under-developing and highly precise and site specific measurement of BMD may provide the predictive power needed for assessing fracture risk in individual subjects.

Absorptiometry, Photon↗
PubMed1990

Quantitative roentgenographic densitometry for assessing fracture healing.

A noninvasive method was developed to assess fracture healing using optical densitometric methodology. Photometric measurements of osseous tissue density were based on illuminance or intensity of light, transmitted through standard roentgenograms. The method was tested in 6-mm tibial segmental defects and single-cut osteotomy defects in adult mongrel dogs. The lowest measureable bone density in the defect was compared to bending rigidity of the involved extremity. For both types of defect, an exponential relationship was found between the densitometric evaluation of the healing fracture gap and bending rigidity. This method proved superior to a roentgenographic scoring method and is capable of detecting small differences in mineral content using standard roentgenograms. The high correlation between densitometric evaluation and bone rigidity indicates this method has potential for use in the in vivo assessment of fracture healing.

Absorptiometry, Photon↗
PubMed1990

[Fundamental evaluation of bone densitometry using dual energy X-ray absorptiometry (DEXA)].

A newly developed instrument based on dual energy X-ray absorptiometry (DEXA), Hologic QDR-1000, was evaluated fundamentally and clinically. Image quality was quite satisfactory though radiation exposure was minimal, 780.2 nC/kg (3.024 mR) for lumbar measurement. Reproducibility of the repeated measurement of a phantom was fairly good; 0.343 CV% in a same day and 0.520 CV% in a long period. Accuracy determined by measurement of potassium phosphate solution was also satisfactory. Bone mineral densities measured by this instrument were fairly correlated with those measured by single energy quantitative CT; coefficient was 0.740 for 17 patients. Mix-DP plates of more than 10 cm thick overestimated the bone mineral densities of a phantom. Bone mineral densities of Japanese normal volunteers were in the normal range (mean +/- 2SD) of the Americans though mostly lower than the mean. In patients with spondylosis deformans or prominent aortic calcification, bone mineral densities might be overestimated. Lateral view was obtainable though its reproducibility was not good. Positioning especially for measuring femoral neck was quite critical for reproducible measurement. In conclusion, this new instrument is quite accurate and satisfactory for clinical application to measuring bone mineral densities.

Absorptiometry, Photon↗
PubMedDate not supplied

[A trial of densitometry in the objective assessment of the x-ray image of the apices of the interdental membranes in periodontal lesions].

The authors suggest a method to assess the quality of filling dental contact surfaces, based on determination of the relative contrast index (RCI) of the x-ray image of interdental septal apexes at the site of filled and intact teeth on the same image. Analysis of their own findings has lead the authors to a conclusion that assessment of the tooth filling with the use of periodontal and hygienic indexes is not strictly consistent because it is subjective, whereas the RCI permits a follow-up of changes in the mineral content of the bone in the examined site over time.

Absorptiometry, Photon↗
PubMed1988

[A method for studying the bone mass: dual-photon densitometry].

The assessment of bone mineral mass during growth, periods diseases or therapy which modify bone mineralization in the child is of great interest. Single-photon absorptiometry carried out on forearm bones informs on the mineral density of the compact bone of the appendicular skeleton. It is easy to perform in children and infants. Dual-photon absorptiometry appears to be the most accurate for measuring bone mineral content in endocrine and metabolic bone disorders. The low dose of radiation and the non-invasive nature of this high-precision method render it well-adapted and suitable for measuring bone mineralization in childhood.

Bone Development↗