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PubMed1998

Risk assessment for osteoporosis using bone mineral density determination: a belgian perspective.

The availability of bone densitometry in daily clinical practice has revolutionized the capacity to detect osteoporosis, to estimate the risk of future fracture, and to select those patients who are likely to benefit most from preventive or therapeutic measures. In spite of the high availability of densitometry in Belgium and the high incidence of risk factors for osteoporosis in elderly women, osteoporosis is presumably underdiagnosed. It is likely that the limited use of widely available technology to evaluate osteoporosis results from a complex interaction of numerous factors, some of which are discussed. In spite of many unanswered questions, the main conclusion to be drawn from the Belgian experience is that a high density of densitometry facilities is no guarantee that the majority of women who are at greatest risk of fracture will actually become the focus of preventive measures or therapy.

Journal Article↗
PubMed2002

A national random survey of bone mineral density reporting in the United States.

The rapidly evolving technology of bone mineral density (BMD) testing has revolutionized the clinical care of osteoporosis; however, at present, there are no guidelines for BMD reporting. A survey was mailed to a random sample of bone densitometry centers in the United States registered in the National Osteoporosis Foundation database in order to evaluate the practice of BMD reporting in the United States. Of the 1200 questionnaires mailed, 22.5% were completed and returned. Spine and hip BMD were routinely measured at 71% of the centers and were expressed as T-scores by 90% of centers. The World Health Organization working group definition of osteoporosis was included in the report by 64% of the survey responders and was used as the sole criterion to make treatment recommendations by 34%. Fracture risk was reported by 70% of the centers and only the minority (<15%) applied appropriate age and gender restrictions. There were geographic and specialty variations in the practices of bone density reporting. Despite the established value of clinical densitometry in the care of patients at risk for osteoporosis, our survey revealed that clinical information, including fracture risk, was missing from many reports. A re-examination of the practice of clinical densitometry reporting is warranted.

Absorptiometry, Photon↗
PubMed2003

Automated assessment of exclusion criteria for DXA lumbar spine scans.

Modern bone densitometry systems using dual-energy X-ray absorptiometry (DXA) automatically analyze lumbar spine scans and provide clinically important information concerning spine bone mineral density (BMD) and fracture risk. Lumbar spine BMD accurately reflects skeletal health and fracture risk in most cases, but degenerative diseases associated with aging may lead to the formation of reactive bone (osteophytes) and other confounding conditions that elevate BMD without a concomitant increase in bone strength or decrease in fracture risk. Automated densitometry software known as computer-aided densitometry (CAD) (GE Medical Systems Lunar) assists the user in identifying scans with common acquisition and analysis irregularities known to influence BMD values. Visual examination of 231 female spine scans measured with DXA found abnormal conditions that could influence BMD results in 29% of scans. The sensitivity and specificity of several criteria for identifying scans with conditions that could influence BMD were determined. A good criterion for identifying scans with abnormal conditions was a T-score difference of greater than 0.9 or 1.0 between L1-L4 mean and individual vertebrae. Criteria for excluding affected vertebrae were determined. Exclusion of affected vertebrae resulted in a mean BMD decrease of nearly 0.6 SD (T-score) among affected scans.

Absorptiometry, Photon↗
PubMed2005

Evaluation of practical use of bone age assessments based on DXA-derived hand scans in diagnosis of skeletal status in healthy and diseased children.

The assessment of bone age is an important factor for the analysis of skeletal maturity, growth, and its aberrations. The classical method of bone age estimations is based on the recognition of changes in the radiographic appearance of the maturity indicators in hand-wrist radiographs by comparison with reference atlas. To apply bone age assessments, based on dual-energy X-ray absorptiometry (DXA)-derived hand scans, in the evaluation of skeletal status, 151 healthy children (4-18 yr old) and 61 with bone disorders (5-20 yr old) were investigated. All measurements were performed using Expert-XL and DPX-L densitometers (GE Lunar). Hand densitometry performed by the Expert-XL machine was used for the evaluation of bone age. Total-body measurements were performed using DPXL to calculate total-body bone mineral density (BMD) Z-score values as standard diagnostic parameters in pediatric densitometry and to verify diagnosis by taking into account assessed bone age. Strong correlations were found between BMD (g/cm2) and bone age in healthy children of both genders. We noted in several cases that low values of Z-scores (<-1) corresponded to delayed bone age in comparison to chronological age. After recalculation of BMD data according to bone age, a marked increase in Z-scores was noted, mainly in multihormonal pituitary-deficient subjects. It can be concluded that the use of hand densitometry in parallel with BMD measurements provide valuable information about skeletal maturation that leads to the improved diagnosis of skeletal status, especially in subjects with constitutional delay in growth.

Absorptiometry, Photon↗
PubMed2004

Assessment of photosensitizer dosimetry and tissue damage assay for photodynamic therapy in advanced-stage tumors.

Photodynamic therapy (PDT) efficacy is a complex function of tissue sensitivity, photosensitizer (PS) uptake, tissue oxygen concentration, delivered light dose and some other parameters. To better understand the mechanisms and optimization of PDT treatment, we assessed two techniques for quantifying tissue PS concentration and two methods for quantifying pathological tumor damage. The two methods used to determine tissue PS concentration kinetic were in vivo fluorescence probe and ex vivo chemical extraction. Both methods show that the highest tumor to normal tissue PS uptake ratio appears 4 h after PS administration. Two different histopathologic techniques were used to quantify tumor and normal tissue damage. A planimetry assessment of regional tumor necrosis demonstrated a linear relationship with increasing light dose. However, in large murine tumors this finding was complicated by the presence of significant spontaneous necrosis. A second method (densitometry) assessed cell death by nuclear size and density. With some exceptions the densitometry method generally supported the planimetry results. Although the densitometry method is potentially more accurate, it has greater potential subjectivity. Finally, our research suggests that the tools or methods we are studying for quantifying PS levels and tissue damage are necessary for the understanding of PDT effect and therapeutic ratio in experimental in vivo tumor research.

Animals↗
PubMed1998

Partitioned weight loss and body composition changes during a mountaineering expedition: a field study.

Weight loss and changes in body composition are recognized phenomena associated with high-altitude mountaineering expeditions. Attempts to partition the weight loss between fat mass (FM) and fat-free mass (FFM) have been inconclusive. Therefore, five male subjects, average age 40.0 +/- 5.5 years, were studied prior to, during, and following a 21-day expedition between 2200 m and 4300 m on Mt. McKinley, Alaska. Pre- to postexpedition body composition changes were determined by densitometry, skinfold thickness (12 sites), body girth measurements (14 sites), and cross-sectional area from magnetic resonance imaging (MRI) (three sites). Data analysis by Student's t-test (p < 0.05(1) tail) indicated decreases in body weight (4.2 +/- 2.8 kg, 220 g/day, 5.4% of initial weight), total skinfold thickness (10.8%), total body girth (2.8%), and percentage of fat by densitometry (15%). Total cross-sectional area of the three MRI slices (upper arm + thigh + calf) decreased 4.7%, muscle area decreased 9.1%, and fat area decreased 3.9%. The three methods used to partition the weight loss between FM and FFM did not agree: 77% FM vs 23% FFM by densitometry, 25% FM vs 75% FFM by skinfolds, and 38% FM vs 62% FFM by MRI. Energy intake (3640 +/- 1250 kcal/day) was negatively correlated (Pearson r > 0.88(2) tail) with losses in weight (r = -0.89), skinfolds (r = -0.93), and girths (r = -0.88), ie the greater the intake the less the decline. Therefore, insufficient energy intake appeared primarily responsible for the weight loss and changes in body composition during the expedition.

Absorptiometry, Photon↗
PubMed2002

Impact of degenerative radiographic abnormalities and vertebral fractures on spinal bone density of women with osteoporosis.

CONTEXT: Measurements of bone density taken by dual-energy x-ray absorptiometry are the most accurate procedure for the diagnosis of osteoporosis. This procedure has the disadvantage of measuring the density of all mineral components, including osteophytes, vascular and extra vertebral calcifications. These alterations can influence bone density results and densitometry interpretation. OBJECTIVE: To correlate radiography and densitometry findings from women with osteoporosis, analyzing the influence of degenerative processes and vertebral fractures on the evaluation of bone density. DESIGN: Retrospective study. SETTING: Osteoporosis outpatients' clinic at Hospital das Clínicas, Universidade Estadual de Campinas. PARTICIPANTS: Ninety-six postmenopausal women presenting osteoporosis diagnosed by bone density. MAIN MEASUREMENTS: Bone mineral density of the lumbar spine and femoral neck were measured by the technique of dual-energy x-ray absorptiometry, using a LUNAR-DPX densitometer. Fractures, osteophytes and aortic calcifications were evaluated by simple x-rays of the thoracic and lumbar spine. RESULTS: The x-rays confirmed vertebral fractures in 41.6%, osteophytes in 33.3% and calcifications of the aorta in 30.2%. The prevalence of fractures and aortic calcifications increased with age. The mean bone mineral density was 0.783g/cm2 and the mean T-score was - 3.47 DP. Neither fractures nor aortic calcifications had significant influence on bone mineral density (P = 0.36 and P = 0.09, respectively), despite the fractured vertebrae having greater bone mineral density (P < 0.02). Patients with lumbar spine osteophytes showed greater bone mineral density (P = 0.04). Osteophytosis was associated with lumbar spine bone mineral density after adjustment for fractures and aortic calcifications by multiple regression (P = 0.01). CONCLUSION: Osteophytes and lumbar spine fractures can overestimate bone density interpretation. The interpretation of densitometry results should be carried out together with the interpretation of a simple lumbar spine x-ray in elderly women.

Absorptiometry, Photon↗
PubMed2002

[Usefulness of a dose distribution analysis system with a common scanner].

Although one-dimensional densitometry has been widely performed for linac dosimetry, it is a time-consuming, labor-intensive procedure. We studied a new densitometry system (DD-System) that consists of a personal computer and common flatbed-type scanner, with regard to its usefulness for daily QC checks in comparison with conventional densitometry. The spatial resolution of the DD-System is very high, and its accuracy of measurements of field size and flatness are equivalent to those of a conventional system at an optical density <2.0. Although the performance of the image scanner limits the maximum optical density of our system, this system can acquire high-resolution two-dimensional dose distributions quickly and easily. In conclusion, the DD-System is very useful for reducing the amount of time and effort required in daily QC activities. We consider this system applicable to the analysis of complicated dose distributions in this era of IMRT.

Phantoms, Imaging↗
PubMed1999

[Changes in cytoskeletal proteins in childhood cataract lenses].

PURPOSE: Approximately 50% of congenital and childhood cataract seen in the clinic is of undetermined origin. Biochemical analysis of the cataracts is rare. This study analyzes lens proteins to determine the mechanism of congenital and childhood cataracts. METHOD: We analyzed the lens proteins from 10 young patients after cataract operations, using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), densitometry analysis, and western immunoblotting. RESULTS: Densitometry of separated proteins showed a decrease in the high molecular protein bands of posterior subcapsular cataract (PSC). Specifically, spectrin (235 kDa), filensin (100 kDa), and vimentin (57 kDa) were absent from the SDS-PAGE of PSC. Increases in filensin and vimentin were observed in a Christmas tree cataract and lamellar cataracts. Western immunoblots confirmed the densitometry of SDS-PAGE. CONCLUSION: These results suggest that changes in cytoskeletal proteins may contribute to congenital and childhood cataract.

Adolescent↗
PubMed1999

[Bone mineral density in primary hyperparathyroidism].

UNLABELLED: Skeletal complications of advanced hyperparathyroidism include clinically bone pains, muscle weakness, bone deformities and fractures. X-ray studies reveal subperiosteal bone resorption, atrophy of the cortex of long bones, cysts, brown tumours and calcifications of soft tissues; these changes appear in the late period of the disease. In recent onset of hyperparathyroidism bone changes may be detected by X-ray absorptiometry. Thus the aim of our study was to evaluate bone mineral density with the use of dual energy X-ray absorptiometry (DEXA) at two sites: in lumbar vertebral bodies consisting mainly of the trabecular bone and in 1/3 distal part of the radius composed predominantly of the cortical bone. Twenty-three patients with primary hyperparathyroidism were included in our study. Hypercalcemia (ionized calcium above 5.4 mg/100 ml, total calcium above 10.6 mg/100 ml) and increased serum PTH, above 100 pg/ml, were detected in all patients. Isotope scintigraphy using 99mTc-MIBI revealed the presence of a parathyroid adenoma; this was confirmed at surgery and histopathologically. In bone densitometry we found greatly reduced bone mineral density (BMD) in 1/3 distal part of the radius amounting to 66.8 +/- 12.0% of the age-matched range and markedly smaller bone loss in lumbar spine, BMD was 91.7 +/- 14.6%. In 10 patients control densitometry, performed 6-24 months after parathyroid adenomectomy, revealed a marked 10 to 22% increase in bone density of lumbar vertebral bodies in the first year. BMD of the 1/3 distal part of the radius increased to a smaller degree 6.3% per year. CONCLUSIONS: 1. Bone densitometry in primary hyperparathyroidism reveals pronounced decrease in bone mineral density in the 1/3 distal part of the radius and much smaller decrease of the lumbar spine density. 2. Parathyroid adenomectomy leads to a rapid increase in density of the trabecular bone L1-L4 vertebral bodies and much smaller increase in the cortical bone of the radius. 3. Pronounced differences in bone mineral density of cortical bone and trabecular bone surpassing 20% are characteristic of hyperparathyroidism as they do not occur in other types of osteoporosis.

Absorptiometry, Photon↗
PubMed1999

[The rationalization of the follow-up of hormonal replacement treatment in menopause].

BACKGROUND: Decision making about the opportunity of starting or continuing hormone replacement therapy (HRT) in menopause should rely on an overall evaluation of its risks and benefits for the women's health; the evaluation of HRT cost-benefit ratio, however, should include its possible outcomes from an economical point of view. In this view, and with the certainty that menopausal patients should be protected by proper treatments, our case series has been evaluated in order to improve the quality of our clinical schedules for both their access to HRT and the treatment follow-up. METHODS: Two groups of patients have been considered the first one consisted of 560 women observed during '97 for climacteric symptoms and candicated to begin HRT. The second one consisted of 100 women on HRT for 1 to 6 years. In the first group we considered which test and with which frequency were responsible for stopping or delay the beginning of therapy; while in the second group we evaluated the reasons for stopping treatment. RESULTS AND CONCLUSIONS: On the basis of our experience, the exams required before starting HRT seem to be the following: patient history, mammography, densitometry and endometrial sample as well as the parameters of glucose lipidic, coagulative and hepatic metabolism. Densitometry is useful in the annual follow-up only in patients with bone alterations from the beginning. The same exams seem required for the follow-up, with the exception of bone densitometry which should be performed yearly only in patients with bone demineralization.

Climacteric↗
PubMed2001

Bone mineral density in patients with psoriatic arthritis.

OBJECTIVE: Little information is available concerning bone mass in patients with psoriatic arthritis (PsA): the existence of less severe periarticular osteoporosis is considered possible, but there are no data concerning the existence of systemic osteoporosis. We investigated bone mineral density (BMD) in patients with PsA. METHODS: We studied 186 patients with non-axial PsA and 100 healthy subjects, equally divided into 3 groups: women of child-bearing age, women in menopause, and men. No patient had previously received steroid treatment. In all patients, evaluation was made of disease duration, inflammation indices (erythrocyte sedimentation rate, C-reactive protein), functional indices (Steinbrocker scale), and the Health Assessment Questionnaire (HAQ). BMD was measured by fan-beam x-ray densitometry of the lumbar spine, femur, and total body (evaluating the whole skeleton, as well as the spine, trunk, and upper and lower limbs). Ultrasound densitometry of the heel was also performed. RESULTS: BMD was significantly lower in the arthritic than in the healthy subjects regardless of sex, menopausal status, or age, as expressed in g/cm2 (lumbar spine 1.112 vs 1.326; femoral neck 0.870 vs 1.006; total body 1.125 vs 1.203) or by T and Z scores (lumbar T = -1.36, Z = -0.98; femoral neck T = -1.12, Z = -0.83; total body T = -1.09, Z = -0.65). Ultrasound densitometry of the heel was similarly altered (stiffness 96 vs 77; T -1.78; Z -1.29). Among the PsA patients, demineralization in at least one skeletal region was observed in 67% of premenopausal women (marked in 11%), 100% of postmenopausal women (marked in 47%), and 80% of the men (marked in 29%). In premenopausal women, demineralization did not correlate with the disease variables; in postmenopausal women and the men, it correlated with a decline in the functional indices and the HAQ score. This was confirmed by analysis of the relative risk of osteoporosis expressed in odds ratios (HAQ: 1.6; age: 1.4; years since menopause: 1.7). CONCLUSION: Demineralization was observed in more than 2/3 of our PsA patients without axial involvement. This demineralization was not related to the indices of inflammation or disease duration, but there is a delayed correlation with HAQ score, as well as age and the number of years since menopause.

Absorptiometry, Photon↗
PubMed2002

Preventive screening. What factors influence testing?

OBJECTIVE: To determine factors associated with having preventive screening tests in a population-based sample of Ontario women. DESIGN: Secondary analysis of data from Statistics Canada's National Population Health Survey linked to data from the Ontario Health Insurance Plan to ascertain whether women aged 20 or older had Pap smears, mammography, bone densitometry, or cholesterol testing. Factors associated with having testing were subjected to logistic regression analysis. SETTING: Ontario. PARTICIPANTS: Women aged 20 or older; from 19,600 Canadian households, 2232 Ontario women gave consent to linkage of administrative databases. MAIN OUTCOME MEASURES: Age-specific population screening rates. Odds ratios and probabilities of having screening in relation to socioeconomic, geographic, and physician-associated factors. RESULTS: Having screening was associated with age, income, education, and place of residence. Women with regular physicians were more likely to have Pap smears (odds ratio [OR] 4.4, range 1.7 to 12), densitometry (OR 22, range 3.6 to 140), and cholesterol testing (OR 8.0, range 2.3 to 29). Women who had periodic health examinations were more likely to have Pap smears (OR 6.7, range 4.6 to 9.8), mammograms (OR 3.7, range 2.3 to 5.9), densitometry (OR 3.7, range 1.3 to 10.5), and cholesterol testing (OR 3.0, range 2.0 to 4.5). The probability of having testing increased with number of visits a year to a doctor, but ceased to increase after three visits. CONCLUSION: Having screening tests was associated with socioeconomic factors including income, education, and place of residence. Patients who went to doctors for episodic care only were less likely to have preventive screening than patients who went for periodic health examinations.

Adult↗
PubMed1992

Estimation of computerized tomography derived abdominal fat distribution.

Measurements of intra-abdominal fat (IAF) may be important since it is associated with numerous metabolic disorders. The relationship between computerized tomography (CT) measured fat distribution and densitometry measures was investigated in a sample of 61 male Caucasian subjects, aged 18 to 30 years with varying adiposity. Regression models were developed for estimating CT-derived fat of 40 men to estimate IAF. Two equations were developed to estimate IAF. The first used only anthropometric measures. Waist circumference and log chest ratio entered the equation and accounted for 67% of the variance. The second model included densitometry-measured percentage fat with the centred product of waist and hip circumferences, accounting for 73% of the variance. Regression equations were also developed to estimate subcutaneous fat area so that the ratio of IAF to subcutaneous fat might be estimated. Although subcutaneous fat could be estimated, the ratio between IAF and subcutaneous fat could not be estimated accurately. A validation of all regression equations developed for male subjects who also completed using a separate validation sample (n = 21). Only the studies with sample characteristics similar to those found in the validation sample validated satisfactorily. Results indicate that anthropometric and densitometry measures cannot be used to estimate CT-derived abdominal fat with precision, however they may be of value in health risk screening of individuals with high levels of IAF. Proper selection procedures with regard to age, adiposity, and morbidity must be used.

Adipose Tissue↗
PubMed1990

[Fundamental study of alveolar bone measurements in the hamster using an apparatus for intraoral radiography].

Morphometry of bone resorption in experimental periodontitis is performed primarily by radiography after sacrificing the animal or by microscopy of histopathologic specimens prepared from resected jaw bones. Both techniques are recognized as effective examinations. However, these are cross-sectional procedures involving resection of specimens, and for evaluation of changes in symptoms from reversible to irreversible, which are characteristic of periodontal diseases, or for follow-up of the aging process, application of standard radiography and a method to properly interpret the images obtained are needed. The author designed an apparatus that allows in site radiographic evaluation of individual animals, which has not been considered in conventional morphometric analyses of periodontal bone resorption. With this apparatus, radiograms are obtained by placing a soft X-ray film in the oral cavity and exposing it with a soft X-ray projector. As a fundamental study of the usefulness of this apparatus, author evaluated the optimal conditions of radiography for imaging of soft tissues, the accuracy of the measurements, and the method for bone measurement. Experimental bone resorption was induced in the mandibular alveolar bone of the hamster, the changing lesion was radiographed daily with this apparatus by the standard procedure, and measurements were attempted by the length measuring method and densitometry method. The following results were obtained: 1) The intraoral apparatus was designed to allow radiography of both sides of the mandibular molar regions of the hamster. The apparatus consisted basically of a film cartridge, an opening, and a fixing portion. The projection angle can be adjusted by the fixing portion so that soft X-ray is always projected orthoradially on the surface of the film, and the soft X-ray film can be kept attached to the hamster mandibular molar region by microadjustment of the opening and the calibrations for angle adjustment. With this apparatus, the percent enlargement was minute at 0.43%, and the reproduced image showed a correlation of 0.998 with the standard. (2) The radiographic conditions of a focus-film distance of 30 cm. acceleration potential of 40 kV, current of 2.5 mA, and projection time of 20 sec. were considered to be optimal in hamsters with regard to the quality of the image and stress to the animals. 3) Palladium used as a reference for densitometry was highly manipulatable with a maximum thickness of 0.1 mm and was appropriate for estimation of the mineral content of the hamster mandibular bone. 4) According to morphometry of the hamster lower jaw alveolar region by the length measuring method and the densitometry method in serial standard soft X-ray images, bone absorption was greater in the order of the diet + inoculation group, diet group and control group in a decreasing order. In the control group, the growth of the bilateral alveolar region reached a peak 23 weeks (about 165 days) after birth, and bone resorption probably due to aging was thereafter observed at the apex of the alveolar bone.

Alveolar Bone Loss↗
PubMed1994

[Bone density measurements and their indications].

Today the following two methods of measuring the bone mineral density (BMD) are widely used: dual-photon absorptiometry with X-rays (DEXA) and quantitative computed tomography (qCT). DEXA measures the BMD of the vertebral column, the femur and the whole skeleton, qCT the vertebral column and the radius and tibia. The qCT method permits a distinction to be made between trabecular and cortical bone, which offers an advantage in terms of the choice of treatment because cortical and trabecular bone do not change in parallel. For example, fluorides are contraindicated when cortical bone is diminished. There are important differences among the methods of densitometry concerning reproducibility. The highly sensitive method of peripheral qCT (Densiscan) has an overall reproducibility of 0.3% (mixed population), allowing a change in BMD of less than 1% to be detected. This enables us to adapt quickly the treatment according to the stage and progression of the disease. In the perimenopausal patient, bone mineral densitometry is indicated to detect high-risk patients; in the postmenopause patient, densitometry should be performed in order to "tailor" the treatment of osteoporosis. Patients with a "slow loser" osteoporosis are preferably treated with bone-simulating substances (e.g., fluorides, ossein-hydroxyapatite compound), patients with a "fast loser" osteoporosis (trabecular bone loss, measured at the distal radius, of more than 3.5% per year) with anti-resorption agents such as estrogens, bisphosphonates, calcitonin and anabolic steroids. This tailored treatment reduces not only the number of non-responders, but improves patient compliance because it allows the choice, duration or change of the treatment to be substantiated by means of hard data.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1993

[Digital subtraction angiocardiography: reliability of densitometric determination of left ventricular volume and ejection fraction].

The angiographic assessment of left ventricular volume (LV) and ejection fraction (EF) by means of the area-length method (ALM) is based upon geometric assumptions, which might lead to erroneous results. With the development of digital subtraction angiocardiography in real-time, densitometric procedures of calculating left ventricular parameters can be used on-line. This study examines both reliability and accuracy of a densitometric technique for evaluating LV and EF in comparison to the single-plane ALM. Contrast images of heart casts and left ventricular angiograms of 54 patients suffering from different cardiac diseases were obtained by the image acquisition and processing system Polytron 1000 VR (Siemens AG, Erlangen, FRG). Digital images of both heart casts and patients were evaluated densitometrically and geometrically by two independent observers. In the phantom study the densitometric method exhibited a significantly (p < 0.01) better agreement with the true values than the ALM. The evaluation of left ventricular angiograms in patients comparing densitometry with the ALM demonstrated a relatively high residual deviation (enddiastolic volume Syx = +/- 27 ml, endsystolic volume Syx = +/- 19.4 ml). This is mainly due to systematic, method-related errors of densitometry and the morphometric technique. The intra- and interobserver variability in calculating EF showed a significantly (p < 0.05) smaller residual deviation for densitometry than for ALM; no significant differences were found for the calculation of LV. In conclusion, we demonstrated that the presented densitometric technique offers an objective and simple means of determining LV and EF with comparable reliability and validity to the area-length method.

Absorptiometry, Photon↗
PubMed1996

Prevention and management of osteoporosis: consensus statements from the Scientific Advisory Board of the Osteoporosis Society of Canada. 2. The use of bone density measurement in the diagnosis and management of osteoporosis.

OBJECTIVE: To determine the best method of diagnosing osteoporosis and determining fracture risk and to promote standards in the use of bone densitometry and the reporting of results. OPTIONS: Methods of bone mineral density measurement: dual-energy x-ray absorptiometry (DXA), radiographic absorptiometry, single-photon absorptiometry, dual-photon absorptiometry, quantitative computed tomography, quantitative ultrasound, neutron activation analysis. The options of using bone densitometry in individual patient management and as a mass screening tool are also considered. OUTCOMES: Appropriate use of densitometry to promote accurate diagnosis and assessment of fracture risk and timely, appropriate treatment. EVIDENCE: Relevant clinical studies and reports were examined. Clinical practice in Canada was also considered. VALUES: Accurate assessment of osteoporotic fracture risk and diagnosis of osteoporosis and assuring low exposure to medical radiation were given a high value. BENEFITS, HARMS AND COSTS: Early diagnosis through bone density measurement allows proper management of osteoporosis to minimize injury and disability, improve quality of life and reduce the personal and social costs associated with the condition. Potential harms include radiation exposure and cost. The harms and costs of appropriate use of DXA are minimal compared with the harms and costs associated with osteoporosis. RECOMMENDATIONS: Bone mineral density should be measured only to assist in making a clinical management choice. DXA is the best method of measuring bone density and, thus, the best available indicator of osteoporotic fracture risk. Plain radiographs may supplement DXA if there is a specific reason for their use. Measurement of the lumbar spine and femoral neck is standard, but a different site or a single measurement is recommended in specific cases. Unless accelerated bone loss is suspected, DXA should be repeated every 2 to 4 years for patients receiving ovarian hormone therapy and 1 to 2 years for patients undergoing bisphosphonate therapy. Measurements and reporting of results must be standardized. Reports should refer to the World Health Organization's recommended definitions of osteopenia and osteoporosis and provide actual measurement and its relation to peak bone mass.

Aged↗