Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Densitometry”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 559 records · Page 31Linked to original sources
PubMed2005

Precision assessment and radiation safety for dual-energy X-ray absorptiometry: position paper of the International Society for Clinical Densitometry.

Measurement of bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA) is used to diagnose osteoporosis, assess the risk of fracture, and monitor changes in BMD over time. Because biological changes in BMD are usually small in proportion to the error inherent in the test itself, interpretation of serial BMD tests depends on knowledge of the smallest change in BMD that is beyond the range of error. This value, called the least significant change (LSC), varies according to the instrument used, the patient population being tested, the measurement site, the skill of the technologist at positioning the patient and analyzing the test, and the confidence interval used in the calculation. The precision and LSC values provided by the manufacturer cannot be applied to clinical bone densitometry centers because of the differences in the patients being tested and the technologist performing the test. Because harmful errors in clinical management may occur from incorrectly interpreting serial BMD tests, it is recommended that every DXA technologist conduct a precision assessment and calculate the LSC for each measurement site and DXA instrument used. Precision assessment provides direct benefit to patients by allowing clinicians to make clinical decisions based on genuine change or stability of BMD. The patient-care benefits of precision assessment outweigh the risk of exposure to trivial doses of ionizing radiation.

Absorptiometry, Photon↗
PubMed2005

Prospective identification of postmenopausal osteoporotic women at high vertebral fracture risk by radiography, bone densitometry, quantitative ultrasound, and laboratory findings: results from the PIOS study.

Women with established osteoporosis are at high risk to sustain additional vertebral fractures. Treatment may affect the predictive power of bone densitometry and biochemical techniques. There are few prospective studies comparing fracture prediction by dual-energy X-ray absorptiometry (DXA) and other techniques in treated women with established osteoporosis. The objective of this study was to prospectively assess the predictive power of various DXA and quantitative ultrasound (QUS) techniques for identification of women at high risk to develop new fractures over 1-2 yr. Moreover, we wanted to investigate whether previous or ongoing therapy precluded the use of common clinical laboratory blood tests and bone turnover markers for prediction of fracture risk. We measured prevalent fracture status; bone mineral density (BMD) of the whole body, spine, and hip by DXA; QUS of the calcaneus and the patella; hormones and various markers of bone resorption and formation; and took standard blood tests in 124 women (age 64.9 yr +/- 7.9) with manifest and variously treated postmenopausal osteoporosis. Subsequently, new spine fractures were assessed after 1 yr and, in a subset of 87 women, after 2 yr. Prevalent fractures turned out to be the strongest predictor of subsequent vertebral fractures with an age-adjusted odds ratio (OR) of 3.9 per prevalent fracture over 2 yr. Furthermore, our results underline the predictive power of spinal BMD (sOR = 2.1; standardized OR per 1 standard deviation population variance decrease), whole body BMD (sOR: 2.4), and QUS stiffness index of the calcaneus (sOR: 2.8) for vertebral fracture prediction. QUS of the patella did not predict vertebral fractures. Blood sedimentation rate was predictive in the first year (sOR: 1.9). The predictive power of bone turnover markers, however, appeared to be too low to be detectable in a group of this sample size and it may have been reduced because most women were already receiving treatment. In conclusion, radiographic measures, but not the tested laboratory bone turnover markers, enabled us to identify women (from a population of osteoporotic women who have been treated for some time with a variety of medications) who are at highest risk for developing new vertebral fractures within 1-2 yr.

Absorptiometry, Photon↗
PubMed2004

[Influence of season on bone mineral densitometry].

OBJECTIVE: In places where sun exposure during the winter is limited, bone mineral density (BMD) may present seasonal variations, increasing during the summer and decreasing during the winter period. There have been suggestions that this variation could influence prospective evaluations of BMD studies. The aim of this study was to evaluate if the seasons of the year (summer/winter) are associated to variations in BMD values. METHODS: Clinic based cross-sectional study, conducted in the state of Rio Grande do Sul (RS). Densitometric studies representative of the periods of winter/summer were selected. The densitometric studies were realized in a Hologic 4500 unit, using dual energy X-ray absorptiometry. RESULTS/CONCLUSIONS: Of 853 densitometric measurements realized during a 12-month period, 201 were realized in the summer, and 321 in the winter. The BMD measurements, corrected to body weight, did not differ between the group of individuals that were tested in the summer or winter (P>0.05). In conclusion, in RS, the season of the year did not affect the BMD results, and does not need to be taken into account when analyzing densitometry measurements. This finding probably could be extrapolated to other regions of Brazil, since winter in those areas is less severe than in RS.

Adult↗
PubMed1988

CT densitometry of pulmonary nodules in a frozen human thorax.

The influence of (1) calcium concentration, (2) exposure technique, (3) reconstruction algorithm, (4) nodule size, and (5) nodule location on the CT attenuation values (CT density) of pulmonary nodules was examined in a frozen human thorax. Nodules with calcium concentrations of 0-310 mg/ml and diameters of either 0.95 or 1.59 cm were inserted into a frozen, unembalmed human thorax. The nodules were placed either at the lung apex or 4 cm below the tracheal carina. Each nodule was scanned on a GE CT 9800 scanner; five different exposure techniques were used. The slice thickness was uniformly 1.5 mm. As expected, increasing the kilovoltage caused a significant decrease in CT nodule density in all nodules with calcium concentrations greater than 80 mg/ml. The inverse relationship between kilovoltage and nodule density was exaggerated with increasing calcium concentration. A high-resolution (bone) algorithm gave a significantly higher CT number than did a smoothed (standard) algorithm, regardless of nodule size and location, but this difference could be attributed almost entirely to the edge-enhancement effect of the bone algorithm. The CT density of the larger nodules was significantly higher than that of the smaller nodules at calcium concentrations greater than 65 mg/ml for both standard and bone algorithms. Densities were significantly higher in the mid lung than in the apex with a standard algorithm, but this was not the case with a bone algorithm. The GE CT 9800 scanner had a linear response between CT density and increasing calcium concentration within the confines of a human thorax. A high-resolution (bone) reconstruction algorithm has higher spatial resolution but does show an edge-enhancing effect not found with the smoothed algorithm. Two major variables in CT densitometry for pulmonary nodules are the kilo electron voltage of the X-ray beam and the reconstruction algorithm used; these two parameters should be standardized, with a high kilovoltage and high-resolution algorithm favored on the GE CT 9800 scanner.

Absorptiometry, Photon↗
PubMed1997

[Relationship between knee pain and X-ray findings of osteoarthritis with reference to bone mineral density measured by computed X-ray densitometry].

We studied the relation between performance of activities of daily living and X-ray findings of osteoarthritis of the knee in aged persons. We made Covariance Structure Analysis models of knee pain, X-ray findings and bone mineral density as measured by computed X-ray densitometry. The subjects were 257 women aged from 47 to 88 years who were outpatients at an orthopedic clinic. The best-fit model indicated that loss of bone mineral density in metacarpals was associated with X-ray findings of knee-joint degeneration, as well as with knee pain. No relationship was found between knee-joint degeneration and knee pain. These results suggest that bone mineral density should be taken into consideration when interpreting X-ray findings of knee pain. This model incorporates the effects of degeneration of the subchondral bone. In summary, we should use measurements of bone mineral density along with X-ray findings for the diagnosis and treatment of knee osteoarthritis. We may be able to precisely predict knee pain caused by osteoarthritis, by analysis of a model that includes a lesion in joint cartilage.

Absorptiometry, Photon↗
PubMedDate not supplied

Technetium-99m sestamibi scintigraphy and bone densitometry in primary hyperparathyroidism.

OBJECTIVE: To review our recent experience with technetium-99m sestamibi scintigraphy in identification and localization of parathyroid adenomas and to determine bone mineral loss associated with primary hyperparathyroidism. METHODS: Thirty-two double-phase technetium-99m sestamibi scans were obtained in 26 patients (22 female and 4 male patients; age range, 14 to 78 years). Serum calcium and intact parathyroid hormone concentrations were measured before scintigraphy. Histopathologic correlation was obtained in all patients who underwent a surgical procedure. Seventeen patients underwent bone densitometry studies of the lumbar spine and hip with use of dual-energy x-ray absorptiometry. RESULTS: Of the 32 scans, 17 (53%) were suggestive of a parathyroid adenoma ("positive"). In these patients, the mean serum calcium concentration was 2.68 mmol/L and the mean serum parathyroid hormone concentration was 669 pg/mL. Overall, one false-negative scan and one false-positive scan were encountered. The overall sensitivity for surgically proven detection and localization of parathyroid adenoma was 90%. The bone density measurements in patients with positive scans were substantially lower in the lumbar spine (mean T score, 2.9) and in the hip (mean T score, 2.1) in comparison with normal control subjects and significantly lower than in those with a negative scan (spine, P = 0.011; hip, P = 0.015). CONCLUSION: Double-phase technetium-99m sestamibi scintigraphy is highly sensitive and useful in detection and localization of parathyroid adenomas. Patients with primary hyperparathyroidism lose bone mineral from both cortical and cancellous bone sites.

Journal Article↗
PubMed1999

Bone densitometry should be included in the evaluation of candidates for lung transplantation.

Bone loss and fractures are common complications of heart and liver transplantation, and are likely related to high-dose immunosuppressive therapy. We have previously demonstrated that many patients with end-stage lung disease already have osteoporosis and may be at even greater risk for fracture after lung transplantation. The purpose of this study is to determine the incidence of fracture in lung transplant recipients on osteoporosis prevention regimens, the relationship of fracture to pretransplant bone mineral density, and the impact of fracture on quality of life after lung transplantation. Twenty-one lung transplant candidates were prospectively evaluated with spine radiographs and bone mineral densitometry. Bone density was expressed as T scores, the number of standard deviations from the mean bone density of a young normal population of the same gender. Of 21 patients, 8 (38%) fractured during the first year. The mean pretransplant lumbar spine T score was significantly lower in the fracture patients (P = .03). Four of the 7 surviving fracture patients and 1 of the 10 patients who survived without fracture believed that chronic pain diminished their quality of life (X2 = 4.408; P = .04). These findings suggest that bone mineral density should be routinely included in the evaluation of lung transplant candidates. Patients with extremely low bone density or osteoporotic fracture should be counseled about the increased risk of fracture after transplantation.

Absorptiometry, Photon↗
PubMed1999

[How to evaluate osteoporosis: bone densitometry and biochemical tests].

The use of bone densitometry, by dual energy x-ray absorptiometry, allows the identification, at an early stage, of subjects who will, 15-20 years later, present a fracture event. Furthermore, this technique is the most appropriate to confirm the efficacy of preventive or curative therapeutic approaches of osteoporosis. A balanced utilisation of biochemical tests is mandatory to exclude a secondary cause of osteoporosis, to help in the choice of the most appropriate therapeutic strategy and to evaluate the early response of patients to the administered drugs.

Absorptiometry, Photon↗
PubMed1999

[Early results of densitometry around the cementless stem of the Parhofer-Mönch hip endoprosthesis].

Fifty-three patients with unilateral hip arthritis (31 females, 22 males) aged from 29 to 66 years (mean 52.1 years) after total hip replacement with cementless Parhofer-Mönch endoprosthesis underwent densitometry. The content (BMC) and mineral density (BMD) of calcium within proximal end of the femur was evaluated at 8-12 days postoperatively and at 6, 12 and 18 months follow-up. Early results show various mineral changes in Gruen zones around the stem. The greatest BMC and BMD decrease was found at 6 months follow-up in zones 1 and 7 as well as 2 and 6. The BMC and BMD tendency to decrease gradually ceased and slightly positive values were found in zone 3, 4 and 5 at the final evaluation.

Absorptiometry, Photon↗
PubMed2000

Computed X-ray densitometry measurement of mBMD & MCI in normal Thai and osteoporotic patients.

To establish the reference values of age-related change of metacarpal bone mineral density (mBMD) and metacarpal index (MCI) in screening for osteoporosis, both postero-anterior (PA) hands and lateral thoraco-lumbar radiography were done on 1,182 normal volunteers aged 17-83. From PA hands radiographs, mBMD and MCI were measured by computed X-ray densitometry (CXD) (Bonalyzer, Teijin Ltd., Tokyo). Exclusion of the surgical menopause condition and the causes of affected bone loss, the results show that mean mBMD and MCI in various age groups were significantly different (p-value < 0.005 for both) in females. Both values increased gradually from age under 20 and peaked in the 30-39 years age group, then decreased gradually until age 50 and decreased markedly after age 50. The yearly rate of bone loss from the peak density detected by mBMD and MCI was 1.3 per cent and 1.6 per cent between aged 50-59, 1.6 per cent and 2.7 per cent in subjects aged 60-69, 1.3 per cent and 3.2 per cent in those aged 70-79. However, mBMD and MCI in males did not show a downward trend with age. It indicated that a screening program for early prevention of osteoporosis may be necessary only in females before, during and after menopause. Because 92.3 per cent of 39 osteoporotic subjects had abnormal CXD measurements lower than -2 standard deviations (SD) limit of mean mBMD in young healthy women (aged 20-40 years), this value appeared to constitute a satisfactory definition of "high risk of developing osteoporosis". The incidence rate of high risk of developing osteoporosis was 3.03 per cent in a normal young population, while the risk rate occurred 4.76, 13.14, 34.28, 47.30 and 47.00 per cent in subjects aged 40-49, 50-59, 60-69, 70-79 and > 80, respectively. Results confirmed the necessity of early prevention of osteoporosis in postmenopausal women. These measurements may be appropriate for mass screening to separate patients who have a greater risk for development of osteoporosis from those at lesser risk.

Absorptiometry, Photon↗
PubMed1999

Single photon bone densitometry in hemodialysis patients.

Renal osteodystrophy is a common finding in patients with renal insufficiency. The maximum of its intensity is found in hemodialysis patients. Bone densitometry is so far the best method for non-invasive assessment of the extent of the illness. Some densitometric studies in hemodialysis patients have already been published but their results differ in prevalence and intensity of renal osteodystrophy. They also demonstrated a slight relationship between intensity of renal osteodystrophy and duration of the dialysis treatment. Opinions vary on the relationship between bone mineral density and markers of bone turnover. This cross-sectional study found high prevalence of renal osteodystrophy (Z-score below -1 in 57% of patients) as well as high a number of severely damaged patients (T-score below -2.5 in 40% of patients). It also showed some correlation between bone demineralisation and the duration of dialysis. None from evaluated markers of bone turnover correlated with bone mineral density.

Absorptiometry, Photon↗
PubMed2000

Development and validation of the Osteoporosis Risk Assessment Instrument to facilitate selection of women for bone densitometry.

BACKGROUND: Although mass screening for osteoporosis is not recommended among postmenopausal women, there is no consensus on which women should undergo testing for low bone mineral density. The objective of this study was to develop and validate a clinical tool to help clinicians identify which women are at increased risk for osteoporosis and should therefore undergo further testing with bone densitometry. METHODS: Using Ontario baseline data from the Canadian Multicentre Osteoporosis Study, we identified all cognitively normal women aged 45 years or more who had undergone testing with dual-energy x-ray absorptiometry (DXA) at both the femoral neck and the lumbar spine (L1-L4). Participants who had a previous diagnosis of osteoporosis or were taking bone active medication other than ovarian hormones were excluded. The main outcome measure was low bone mineral density (T score of 2 or more standard deviations below the mean for young Canadian women) at either the femoral neck or the lumbar spine. Logistic regression analysis and receiver operating characteristic (ROC) analysis were used to identify the simplest algorithm that would identify women at increased risk for low bone mineral density. RESULTS: The study population comprised 1376 women, of whom 926 were allocated to the development of the tool and 450 to its validation. A simple algorithm based on age, weight and current estrogen use (yes or no) was developed. Validation of this 3-item Osteoporosis Risk Assessment Instrument (ORAI) showed that the tool had a sensitivity of 93.3% (95% confidence interval [CI] 86.3%-97.0%) and a specificity of 46.4% (95% CI 41.0%-51.8%) for selecting women with low bone mineral density. The sensitivity of the instrument for selecting women with osteoporosis was 94.4% (95% CI 83.7%-98.6%). Use of the ORAI represented a 38.7% reduction in DXA testing compared with screening all women in our study. INTERPRETATION: The ORAI accurately identifies the vast majority of women likely to have low bone mineral density and is effective in substantially decreasing the need for all women to undergo DXA testing.

Absorptiometry, Photon↗
PubMed2000

Bone densitometry.

Assessment of BMD has become the essential part of evaluation of patients at risk of osteoporosis. It is likely that different BMD technologies will coexist in clinical practice in the future depending on varying clinical needs. DXA is currently the leading bone density technique because it has the capacity to measure axial and appendicular sites, superior monitoring capabilities, and more sophisticated reference databases and quality control procedures. More rapid and portable peripheral devices, such as peripheral DXA, peripheral instantaneous x-ray imager, and QUS, will likely be used for screening. This large variety of available bone densitometry techniques will provide a wide selection for clinicians to choose from. It may also add confusion, however, about which devices should be used and how to interpret data from different techniques. It is critical for clinicians to have a basic understanding of the technology being used, and the clinical advantages and disadvantages of each instrument, to choose properly which test to perform and interpret the obtained results. When combined with other major risks for fracture, such as age and prior fragility fractures, knowledge of the BMD is an invaluable tool in the assessment of patients with known or suspected osteoporosis.

Absorptiometry, Photon↗
PubMed2002

[Opportunities of delayed densitometry of "late (fixed) contrast" as a test for tumors in residual mediastinal lesion in primary mediastinal lymphosarcoma after polychemotherapy].

AIM: To clarify the potential of delayed densitometry of late (fixed) contrast in differentiation between tumor and fibrosis in residual mediastinal lesion (RML). MATERIAL AND METHODS: Computed tomography (computed tomograph of the third generation COMATOM CR-3 made in Germany, SIEMENS) has examined 12 patients with mediastinal lymphosarcomas after polychemotherapy. All of them had a RML 3 to 6 cm in diameter. RESULTS: CT has detected 8 cases of the tumor and 4 cases of fibrosis. The criteria of the tumor were the following: increased RML density shortly after the contrast medium introduction and 30 min after urographine introduction (p < 0.01); RML density 30 min after introduction of contrast medium was higher than above the aorta (p < 0.01). Fibrosis in RML was stated if RML density before, at the high of concentration and after introduction of the contrast medium was the same (p > 0.01); aortic density was significantly higher of RML density at the height of the contrast (p < 0.01). CONCLUSION: The above method differentiates the tumor with fibrosis in RML with maximal probability. This facilitates further choice of therapeutic policy in secondary resistant form of primary mediastinal lymphosarcoma.

Adult↗
PubMed2002

Development and assessment of the Osteoporosis Index of Risk (OSIRIS) to facilitate selection of women for bone densitometry.

A simple questionnaire would be useful to identify individuals most in need of bone mineral density (BMD) testing. We designed a new predictive model and risk assessment instrument based on an extensive review of the literature evaluating risk factors for osteoporosis, and tested its performance in a large cohort of postmenopausal women in whom BMD was measured by dual x-ray absorptiometry. In total, 1303 postmenopausal women from an outpatient osteoporosis clinic participated in this study. The Osteoporosis Index of Risk (OSIRIS) is based on four variables: age, body weight, current hormone replacement therapy use and history of previous low impact fracture. The sensitivity and specificity for an OSIRIS value of +1 were respectively 78.5% and 51.4%. The AUC under the ROC curve of OSIRIS was 0.71. Three categories were arbitrarily created using OSIRIS, with cutoff of +1 and -3. The low risk category (OSIRIS > +1) represented 41% of all women; only 7% of the women in this category had osteoporosis. The prevalence of osteoporosis was very high (66%) among the group at high risk (OSIRIS < -3 representing 15% of all women). The prevalence of osteoporosis was 39% in the intermediate risk group (-3 < OSIRIS < +1, 44% of all women). In conclusion, OSIRIS is a simple index based on four easy-to-collect variables from postmenopausal women, it shows a high degree of accuracy, and performed well for classifying the degree of risk of osteoporosis in western European women of Caucasian lineage. Based on this instrument it is possible to propose a strategy that would initiate treatment in women with very high risk, postpone BMD measurement in women with low risk and limit BMD measurement to women with intermediate risk of osteoporosis, this would spare more than 55% of the densitometry bill compared with a mass screening scenario.

Absorptiometry, Photon↗
PubMed1975

Comparison of the helium rebreathing method and the x-ray film densitometry in epidemiological screening tests of CNSLD (author's transl).

Two methods for the examination of the residual volume were compared under the special conditions of epidemiological studies. The X-ray Photo Densitometry RV/TLC is measured as a quotient of the brightness of the lung radiographs during inspiration and expiration maximums. The Helium Rebreathing method is a gas mixture technique. The correlation between both methods proved to be significant (r = 0,60). The advantages and disadvantages of these methods for epidemiological studies were discussed.

Absorptiometry, Photon↗
PubMed2002

CT densitometry of the brain: a novel method for early detection and assessment of irradiation induced brain edema.

The purpose of the study was to examine if the CT densitometric analysis during radiotherapy (RT) of brain tumors is suitable for the early detection of RT induced brain edema (BE), predicting related neurological progress, and assessing the effects of different edema therapies. Planimetric CT-densitograms were constructed by modifying the "High-Lighting" method. Three theoretical density regions were defined and color-coded on the images of the brain. These were defined as edema (10-20 HU), mild edema, and normal brain (29-38 HU). Corresponding axial CT slices were created at the mid-level of the lesion and that of the periventricular white matter to verify the changes in perifocal and diffuse BE. The monitoring was performed on 50 solitary brain tumor patients treated with RT. During RT courses weekly CT-densitometric examinations were carried out. We experienced that changes in densitograms coincided with clinical symptoms, furthermore, preceded the latter. With the use of preventive edema medication based on diuretics and along with adjunctive edema medication adopted to densitograms, the 5-7 week irradiation was completed without ultimate worsening in performance state in 49 of 50 cases and besides we succeeded in avoiding the routine usage of steroids. Based on our findings the CT-densitometry is suitable for early detection and continuous assessment of BE and preventing patient distress during RT. This simple, reproducible and non-invasive procedure could provide an additional clinical tool for new treatment strategies.

Adult↗
PubMed2003

[Prevalence of osteopenia and osteoporosis assessed by densitometry in postmenopausal women].

OBJECTIVE: Our goal was to know the osteopenia and osteoporosis prevalence, determined by densitometry using dual energy X-ray absorptiometry (DXA) to measure the bone mineral density (BMD) in postmenopausal women. SUBJECTS AND METHODS: A total the 202 postmenopausal women aged 37 at 74 years old was studied, at the Gynecologist and Obstetrics Hospital No. 3 Medical Center "La Raza" from the IMSS, initiated in December 2001 to June 2002. The measurement BMD using DXA with a LUNAR device and according the WHO criteria, we have calculated the prevalence of osteopenia and osteoporosis in normal postmenopausal women at the lumbar spine (LS) and/or femoral neck (FN). RESULTS: The osteopenia prevalence in LS was: 18.2% in the group aged 45-49 years old, 47.1% in the group aged 50-54, 43.7% in the group aged 55-59, 63.6 in the group aged 60-64, 53% in the group aged 65-69, and 30% in the group aged 70-74. The overall osteopenia prevalence in LS was 43.5%, confidence interval (CI) 95% from 43.08 to 44.03%. The osteoporosis of LS was 17.1% in the group aged 50-54 years old; 21.8 in the group aged 55-59; 22.7 in the group aged 60-64; 35.29% in the group aged 65-69; and 30% in the group aged 70-74. The overall osteoporosis prevalence in the LS was 19.8% (CI) 95% from 14.3 to 25.2%. The osteopenia prevalence in FN was. 19% in the group aged 45-49 years old; 40% in the group aged 50-54; 49% in the group aged 55-59; 54% in the group aged 60-64; 76% in the group aged 65-69 and 60% in the group aged 70-74. The overall osteopenia prevalence of FN was the 48% CI 95% from 40.65-54.59%. The osteoporosis prevalence in FN: 2.38% in the group aged 45-49 years old; 7.14 in the group aged 50-54; 5.45% in the group aged 55-59; 13.6% in the group aged 60-64; 5.8 in the group aged 65-69, and 20% in the group aged 70-74. The overall osteoporosis prevalence in FN was 7.4% IC 95% from 3.6-10.68%. CONCLUSIONS: The osteoporosis prevalence in this group is less than between American women (15%), and early detection is possible between women with BMD low, in the postmenopausal women with high risk factors and primary treatment need to be established and implemented.

Absorptiometry, Photon↗