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PubMed1997

[Radiologic diagnosis and densitometry of osteoporosis].

The principles of densitometric and radiological examination in diagnosing of osteoporosis are presented. Peripheral and whole body densitometers are described and their quality is assessed on basis of precision and accuracy of bone mineral density measurements (BMD). WHO criteria of diagnosis, which introduce clinical category of the basis of BMD (expressed in T-scores) are described as follows: normal-(T-score up to -1.0); osteopenia-(T-score below -1.0 but more than -2.5); osteoporosis-(T-score -2.5 or below); severe osteoporosis-(T-score below -2.5 and one or more fractures). Evaluation of osteoporotic changes on the spine, pelvis and hand radiographs are discussed. Quantitative and possible quantitative analysis of radiographs are described.

Aged↗
PubMed1997

New perspectives on bone densitometry.

Methods of bone mineral density measurement are presented. Radiological photogrammetry, single photon absorptiometry, dual photon absorptiometry and dual energy X-ray absorptiometry are described. Mode of work of densitometers and their characteristics ares presented. Modern development of densitometric equipment and possible application in diagnosing of osteoporosis is discussed.

Adult↗
PubMed1997

[Physical aspects of selected densitometry methods used in the diagnosis of osteoporosis].

Physical background of diagnostic procedures currently applied to assess bone mineral density (single and dual X-ray absorptiometry, quantitative computed tomography and ultrasonography) are described. Special emphasis is given to physical interpretation of diagnostic parameters and to the comparison of the procedures. Systematic errors of the procedures is discussed in detail.

Bone and Bones↗
PubMed1998

Peripheral bone densitometry: an old friend revisited.

The earliest assessments of bone "mass" involved metacarpal morphometry that provided insight into age-related changes, the effects of low habitual dietary calcium intake, and the effects of estrogen deficiency and replacement. Single photon absorptiometry (SPA) made quantitative mass measurement possible but this was intellectually unsatisfactory since osteoporotic fractures are more of a concern at the spine and hip than at the wrist. Necessity forced the development of axial bone mass measurement (dual photon absorptiometry--DPA, dual energy xray absorptiometry--DXA, quantitative computed tomography--QCT). Hip measurements provide a better prediction of hip fracture risk than measurements at any other skeletal site. For every standard deviation decrement of bone mass at the hip, relative risk of fracture is 3.0. At non-hip sites the relative risk is only 2.0 for each standard deviation decrement in bone mass. However measurement at non-hip sites provide a fracture risk prediction that is at least the equal of blood pressure measurement for predicting risk of CVA, and substantially better than the risk assessment of acute MI afforded by cholesterol measurement. An important caveat of the superiority of hip measurement is that the data are derived from short-term studies in older women (> 70 years). The relative risk data from phalangeal, forearm, and heel measurements have all been obtained from longer-term studies in younger women. From a community health perspective, bone density measurements, no matter how accurate, precise, and meaningful, have limited value if access to the technology is limited. Peripheral measurements can be obtained on existing radiographic equipment (phalanges), or small, portable, inexpensive dedicated equipment (forearm, heel). This technology is more likely to make it to the office of the primary care physician than the larger, more expensive, dedicated equipment needed for hip measurements. The peripheral measurement technology is also suitable for high traffic areas, just as blood pressure and cholesterol measurements are widely available. This presentation reviewed the scientific validity of peripheral bone mass measurement and explored the potential for making this technology available at non-traditional facilities such as pharmacies, shopping malls, health clubs, etc.

Absorptiometry, Photon↗
PubMed2000

Monitoring osteoporosis therapy with bone densitometry: misleading changes and regression to the mean. Fracture Intervention Trial Research Group.

CONTEXT: The principle of "regression to the mean" predicts that patients with unusual responses to treatment might represent outliers who are likely to have more typical responses if treatment is continued without change. OBJECTIVE: To test whether women who lose bone mineral density (BMD) during the first year of treatment for osteoporosis continue to lose BMD if the same treatment is continued beyond 1 year. DESIGN AND SETTING: Two randomized, double-blind, placebo-controlled trials in 11 US clinical research centers for the Fracture Intervention Trial and 180 centers in the United States and other countries for the Multiple Outcomes of Raloxifene Evaluation Trial. PARTICIPANTS AND INTERVENTIONS: Postmenopausal women with low BMD assigned to treatment with 5 mg/d of alendronate sodium in the Fracture intervention Trial who completed 2 years of BMD monitoring and adhered to study medication (n = 2634), and postmenopausal women with osteoporosis assigned to treatment with 60 or 120 mg/d of raloxifene hydrochloride in the Multiple Outcomes of Raloxifene Evaluation trial who similarly completed 2 years of monitoring while adhering to study medication (n = 3954). MAIN OUTCOME MEASURES: Baseline, 12-, and 24-month hip and spine BMD. RESULTS: Women with the greatest loss of BMD during the first year of treatment were the most likely to gain BMD during continued treatment. Specifically, among women taking alendronate whose hip BMD decreased by more than 4% during the first year, 83% (95% confidence interval [CI], 82%-84%)had increases in hip BMD during the second year, with an overall mean increase of 4.7%. In contrast, those who seemed to gain at least 8% during the first year lost an average of 1% (95% CI, 0.1%-1.9%) during the next year. Similar results were observed among women taking raloxifene for 2 years. CONCLUSIONS: Our data suggest that most women who lose BMD during the first year of treatment with alendronate or raloxifene will gain BMD if the same treatment is continued for a second year. These results illustrate the principle of regression to the mean and suggest that effective treatments for osteoporosis should not be changed because of loss of BMD during the first year of use.

Absorptiometry, Photon↗
PubMed1994

Linear densitometry and digital image processing of proximal femur radiographs: implications for archaeological and forensic anthropology.

Age- and sex-related patterns of proximal femur trabecular bone loss have previously been used to establish radiographic reference standards for estimating age at death for human skeletal remains. Such standards are of interest to both anthropologists and forensic scientists. However, osteopenia as a physiological phenomenon is dependent on numerous genetic, environmental, and cultural factors. Thus, while general age- and sex-related trends can be clearly observed for trabecular bone loss, such patterns also demonstrate marked variation among individuals of both sexes at all ages. Moreover, clinical evidence shows that rates of bone loss are not steady but episodic, and that radiographically "normal" (i.e., young adult) patterns of trabecular bone architecture can also exist in femora of older individuals, particularly within samples of African origin. In this study, adult proximal femur radiographs were used to explore patterns of age- and sex-related proximal femur cancellous bone involution among a sample of 66 African-American individuals from the Terry collection (33 males and 33 females), ranging in age from 19 to 71 years. The proximal femur radiographs of these subjects were analyzed by digital image processing (DIP), and the results were compared to those obtained by laser linear densitometric analyses (LDA) previously performed on the same series (Macchiarelli et al., 1987). Results of LDA and DIP analyses indicate (a) more pronounced bone density decrease in females; (b) sex- and site-specific structural patterns of proximal femur trabecular bone loss; (c) a high level of individual variability, in which predicted age deviated from real age by as much as 22.26 (males) and 30.78 years (females); (d) a moderate linear correlation with age for all the variables analyzed; and (e) an average discrepancy between known age and predicted age (measured by root mean squared residual values) of 10.34 (males) and 12.71 years (females) for the most satisfactory DIP analysis parameter (recorded at the center of the femoral neck in the equalized images). With regard to estimating adult age at death from radiographic images of proximal femora, it is argued that the amount of useful age information reported for this criterion has been overestimated.

Absorptiometry, Photon↗
PubMed1995

Longitudinal study of hand bone densitometry in rheumatoid arthritis.

OBJECTIVE: To measure hand bone mineral content (BMC) by dual x-ray absorptiometry and to seek clinical correlates in patients with rheumatoid arthritis (RA), in a prospective, longitudinal study. METHODS: Eighty-one patients with non-steroid-treated RA were assessed at baseline and at month 12, for hand BMC and for disease activity and severity. Hand BMC in patients was compared with that in a control group of 95 normal volunteers, and rate of loss was compared with that in 37 controls. RESULTS: At the initial assessment, male and female patients with RA had lower hand BMC than controls, after correction for age, height, and weight (mean reduction 7.5% in men [P = 0.003] and 7.8% in women [P = 0.01]). After 1 year, there was a further loss of hand BMC in patients (median loss 3.25% in men [P = 0.001] and 1.46% in women [P = 0.05]), but normal controls did not have significant changes in their hand BMC. In patients with disease duration of < 2 years at study entry, the parameters of disease activity improved over 1 year, but they lost significant amounts of hand BMC. Hand BMC loss correlated with baseline C-reactive protein levels. In those with RA of > 2 years duration at entry, the Health Assessment Questionnaire scores and Larsen scores had worsened after 1 year, but there was no significant loss of hand BMC. CONCLUSION: Patients with RA had low hand BMC compared with normal controls, even within 2 years of disease onset. The rate of loss was highest in patients with early disease and correlated with measures of initial disease activity. This loss continued despite clinical improvement.

Absorptiometry, Photon↗
PubMed1992

Lateral spine densitometry is a more sensitive indicator of glucocorticoid-induced bone loss.

Osteoporosis is a common complication of glucocorticoid therapy. Bone density measurement is now commonly used in assessing which steroid-treated patients require specific interventions to reduce fracture risk. The recently developed techniques for the measurement of bone mineral density (BMD) of the vertebral body alone, by dual-energy x-ray absorptiometry (DXA) in the lateral projection, may be particularly useful in this context since steroid-induced bone loss is most marked in trabecular-rich regions like the vertebral body. This possibility has been assessed in the present study by the measurement of BMD in the lateral and anterioposterior (AP) projections in 28 women receiving chronic glucocorticoid treatment. The two BMD measurements were significantly related (r = 0.62, p < 0.001). When expressed in relation to age-appropriate normal values, lateral BMDs were lower than AP BMDs both in percentage terms (70.8 +/- 4.4 versus 90.3 +/- 2.6%, p < 0.001) and in terms of Z scores (-1.42 +/- 0.22 versus -0.91 +/- 0.24, p = 0.027). AP BMD Z scores classified 12 patients as osteopenic, whereas a further 7 were so categorized by lateral BMD Z score. It is concluded that lateral DXA scanning is a more sensitive indicator of glucocorticoid-induced osteopenia than conventional BMD measurement in the AP projection.

Absorptiometry, Photon↗
PubMed1994

Quality control of bone densitometry in a national health survey (NHANES III) using three mobile examination centers.

A quality control (QC) program for bone mineral measurements at the proximal femur by dual-energy x-ray absorptiometry (DXA) was designed for the osteoporosis component of the Third National Health and Nutrition Examination Survey (NHANES III). Major elements of the QC program are (1) a QC center for review of all scans, (2) setup procedures for and continuous monitoring of daily QC procedures, (3) reference standards for cross-calibration, (4) longitudinal studies for assessment of instrument stability, (5) monitoring of technologist performance, and (6) training. This report describes the results of the QC program of the first half of this 6 year study, which began in 1988. Measurements were performed on 7376 subjects in three mobile examination centers, which traveled to a new location about every 3 months, a total of 44 locations. A small percentage (3.5%) of all scans were rejected, mostly because of patient motion during scanning, but 33% of the remaining scans required reanalysis at the QC center to refine the location of the regions of interest. Precision in spine and hip phantoms was below 1% at all ROIs. In 535 subjects with duplicate scans, age 20-91 of both sexes, examined in a blinded review, precision for BMD at the femur neck ROI was 3.2% (CV) and 5.1% for Ward's triangle BMD. The central review improved scan quality, increased the number of usable scans, and reduced significantly the range of the mean percentage difference in the duplicate scans. Minor alterations in machine function were observed and corrected. QC results on phantoms were similar to those obtained with stationary instruments in dedicated laboratories. Retrospective analysis of the regression slopes from QC records did not show a need for correction of the data base, indicating that the instruments were stable during the course of the study.

Absorptiometry, Photon↗
PubMedDate not supplied

Chemical fingerprinting of Andrographis paniculata using HPLC, HPTLC and densitometry.

An attempt has been made to develop a method by which to determine the chemical fingerprint of Andrographis paniculata (Acanthaceae). High-performance thin layer chromatography (HPTLC) was used to analyse hexane, chloroform, methanol and water extracts of leaves of A. paniculata. A computerised densitometer was applied to the two-dimensional spectrographic image analysis of the HPTLC plates. An HPLC equipped with a photodiode array detector was used for the analyses of these different extracts. The analyses showed that andrographolide and neoandrographolide are absent in the hexane extract but are present in greater amounts in the methanol extract as compared with the other extracts. These chromatograms may serve as a chemical fingerprint of the drug A. paniculata for quality control purposes and in the preparation of formulations based on the drug.

Andrographis↗