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At least 19 recordsLinked to original sources
PubMed2002

Standards and guidelines for performing central dual X-ray densitometry from the Canadian panel of International Society for Clinical Densitometry.

The International Society for Clinical Densitometry (ISCD) is a multidisciplinary nonprofit global organization formed to ensure excellence in densitometry imaging, interpretation, and application. The Canadian panel of the ISCD represents ISCD in Canada and oversees Canadian bone densitometry certification programs. The standards of care from the Canadian panel of the ISCD have been developed in order to establish the minimum level of acceptable performance for the practice of bone densitometry in Canada. A variety of techniques are available for skeletal assessment of bone mineral density, which vary in accuracy, precision, and clinical utility as well as availability. This article focuses on central dual X-ray absorptiometry in adults and does not address densitometry in the pediatric population. Other technologies will be addressed in a subsequent article.

Absorptiometry, Photon↗
PubMed2002

Standards and guidelines for performing central dual X-ray densitometry from the Canadian Panel of International Society for Clinical Densitometry.

The International Society for Clinical Densitometry (ISCD) is a multidisciplinary nonprofit global organization formed to ensure excellence in densitometry imaging, interpretation, and application. The Canadian panel of the ISCD represents ISCD in Canada and oversees Canadian bone densitometry certification programs. The standards of care from the Canadian panel of the ISCD have been developed in order to establish the minimum level of acceptable performance for the practice of bone densitometry in Canada. A variety of techniques are available for skeletal assessment of bone mineral density, which vary in accuracy, precision, and clinical utility as well as availability. This article focuses on central dual X-ray absorptiometry in adults and does not address densitometry in the pediatric population. Other technologies will be addressed in a subsequent article.

Absorptiometry, Photon↗
PubMed1975

[New bases and theories from improving angio-cine-densitometry. II Improvements in the signal-to-noise ratio by the quotient method in cine densitometry].

In radio-cine-densitometry, random variations can be smoothed and reduced in two ways: temporal (frame to frame) and spatial (each frame). Both methods may, however, alter the signal measurements. The advantage of quotient cine-densitometry depends on the elimination of interference or random variations without changing the signal. Elimination of the variations occurs during signal recording. Amongst others the following are eliminated: variations in mains voltage, uneven development, absorption by other tissues and organs. A more suitable signal-to-noise ratio can be obtained. If an artery or a vein are opacified simultaneously it is possible, by means of quotient cine densitometry, to distinguish the arterial and venous phase and to analyse these separately from the overlying tissues.

Absorptiometry, Photon↗
PubMedDate not supplied

[X-ray densitometry of the axial skeleton and ultrasound densitometry of the calcaneus: potentialities and values of the techniques in clinical practice].

Double-power X-ray absorptiometry of the axial skeleton and ultrasound densitometry of the calcaneus were used to examine 3 groups of patients: 58 with chronic renal failure (CRF), 73 with senile osteoporosis, and 78 with diabetes mellitus (DM). The examination has indicated that X-ray absorptiometry is the most informative method in diagnosing osteoporosis in patients with CRF and DM. Ultrasound densitometry is of informative value only in patients with senile osteoporosis and it may be used as a screening tool in this category of patients.

Absorptiometry, Photon↗
PubMed1987

[Determination of bone density of the macerated human radius. Comparison of diverse densitometry methods: computerized axial tomography and single photon ray densitometry].

Bone mineral content (BMC) assays are widely used in clinical practice. The most common techniques in vivo are computed axial tomography (CT) and single photon ray densitometry (SPA). The two techniques were compared in studies of macerated bone (16 macerated radii of both sexes). The BMC was measured first by SPA that provides information on both the trabecular and the cortical bone tissue. CT densitometry was then performed on the cortical bone in the same sites at the SPA. Bone sections were then taken and the area of the depth of the cortical bone calculated on their radiographic images using a semiautomatic image analyser. The results show that data obtained by SPA correlate better with the CT data (r1 = 0.861) than with the figures for the area of the thickness of the cortical bone (r2 = 0.786). This suggests that the BMC of the radius as measured by SPA may depend more on the density than the thickness of the cortical bone.

Aged↗
PubMedDate not supplied

Rod densitometry in night blindness: a review and two puzzling cases. Rod densitometry in night blindness.

Since the non-invasive technque of retinal densitometry became available in 1955, rhodopsin kinetics could be studied in vivo. It was obvious that with this new tool investigators focussed attention on the aetiology of night blindness in various diseases. A brief review about the clinical developments in the past two decades is given. Also three case-reports are presented, which suggest that in some cases of congenital stationary night blindness (CSNB) the night blindness might arise from the absence of rhodopsin. This is contrary to the standing opinion and present problems regarding the integrity of the retina.

Adolescent↗
PubMed1983

Simultaneous Feulgen densitometry and autoradiographic grain counting with the Quantimet 720D image-analysis system. III. Improvements in Feulgen densitometry.

A method has been developed for densitometric estimation of the Feulgen-stained DNA content of 3H-labeled nuclei in autoradiographs in conjunction with automated grain counting using a Quantimet Imaging System. Refinements in the methodology are reported which include 1) the incorporation of an Image-Editor Module into the Quantimet module configuration; 2) the optimization of incident illumination based upon evaluation of various light sources; 3) changes in the optical configuration which reduce glare and minimize the level of monitor shading correction; 4) the optimization of scanner sensitivity; and 5) the evaluation of cell-flattening and staining with respect to densitometry resolution and sensitivity. These refinements resulted in a CV of less than 6.4% in the G-1 and G-2 DNA peaks of rat kidney cells in autoradiographs compared to the previous CV of 10.5%, and a G-2 to G-1 ratio of 2.025. For a fixed field position the CV was 5.1% and the replication error less than 1.0%.

Animals↗
PubMed1998

Calcaneal ultrasound bone densitometry in inflammatory bowel disease--a comparison with double x-ray densitometry of the lumbar spine.

OBJECTIVE: The aim of this study was to measure ultrasound (US) densitometric parameters [Broadband Ultrasound Attenuation (BUA), Speed of Sound (SOS), and stiffness of the os calcis] in patients with inflammatory bowel disease (IBD) and to compare the results with those obtained with conventional x-ray absorptiometry (DXA) of the lumbar spine. METHODS: Twenty-two patients with Crohn's disease (13 with ileal and nine with ileocolonic disease), 11 patients with ulcerative colitis (eight with left-sided and three with pancolitis), and 18 healthy controls. US densitometry of the right heel and DXA of the lumbar spine were performed within the same day. RESULTS: Compared to controls, IBD patients had significantly lower values with both methods, US and DXA. Forty-nine percent of patients had a lumbar T score below -1. Calcaneal SOS and stiffness of these patients were significantly reduced (p < 0.03 and p < 0.05, respectively). Positive significant correlations were found between lumbar DXA and calcaneal US parameters. Lumbar bone density and calcaneal US stiffness correlated inversely with the lifetime prednisone intake (p < 0.03 andp < 0.05, respectively), but not with age or duration of disease. A cut-off level of 80 dB/MHz for calcaneal BUA predicted axial osteopenia correctly in 74%, but some underestimation of spinal BMD was observed, especially in female patients with Crohn's disease. CONCLUSION: US evaluation of the os calcis gives results similar to those of conventional DXA and therefore may be used for screening IBD patients for axial osteoporosis. Because US does not expose patients to radiation, repeated measurements are possible and may be used to assess short term variations and the effect of treatment of IBD-associated bone disease.

Absorptiometry, Photon↗
PubMed1975

[A new basis and theories for improving angio-cine-densitometry. V. The effect of the injection method of the contrast on measurements during angio-cine-densitometry (author's transl)].

The theoretical basis for measuring speed of flow in vessels of conscious patients obtained by estimating dilution of injected contrast is described. Previously, measurements at two separate points had to be carried out in order to obtain a flow profile, but with the present method, a single measurement point is adequate. If contrast is distributed evenly in the circulation during its flow to the periphery, the measurement can be carried out at some distance from the point of injection. The ability to select ones point of measurement makes it possible to avoid areas covered by overlying shadows and eliminates the difficulties inherent in measurements in curved vessels.

Absorptiometry, Photon↗
PubMed2000

[Quantitative ultrasound densitometry (QUS) and dual X-ray densitometry (DXA) in patients with rheumatoid arthritis].

UNLABELLED: The aim of this study was to assess of bone mineral content (BMC) and bone mineral density (BMD) of the forearm using DXA technique (DTX-200) and to evaluate broadband ultrasound attenuation (BUA) and speed of sound (SOS) of the heel using QUS technique (DTU-ONE). We examined 83 RA patients: 73 women and 10 men, at average age (55.0 +/- 12.2 yrs), ranging from 29 to 85 yrs. Average disease duration was 112.6 +/- 98.1 months. Disease activity was assessed according to Mallya and Mace index and radiological stage of the disease according to Steinbrocker index. We found significant correlation between BMC, BMD and BUA (r = 0.6572, r = 0.6081, respectively) and between BMC, BMD and SOS (r = 0.4704, r = 0.4723, respectively). IN CONCLUSION: quantitative ultrasound parameters (BUA and SOS) significant correlate with BMC and BMD values of the forearm assessed by DXA technique in rheumatoid arthritis patients.

Absorptiometry, Photon↗
PubMed2000

[X-ray densitometry and ultrasonography of the heel bone--sensitivity and comparison with densitometry of the axial skeleton].

BACKGROUND: The aim of the study was to determine the relationship between dual energy x-ray absorptiometry (DXA) and quantitative ultrasonometry (QUS) of calcaneus and their correlation with axial bone mineral density. METHODS AND RESULTS: 1284 subjects were tested for BMD (Bone Mineral Density) by DXA at the spine and hip (707 subjects by DPX-L, Lunar, and 577 subjects by QDR-4500 A, Hologic) and calcaneus (by PIXI, Lunar). The calcaneus was also measured using the QUS (Achilles Plus, Lunar), on the same day. The mean age of the patients was 56.5 +/- 11.6 years, mean height 166 cm, mean weight 70 kg. Three subjects were selected for precision error measurement with low, medium and high BMD of calcaneus (T-score of -2.2, -0.77 and 2.02, respectively) and scanned with re-positioning at the right heel (PIXI and Achilles Plus) 21 times on one day for short term precision error and over 21 consecutive days for long term precision error. The in vivo short term precision error of the heel measurement (BMD, SOS, BUA) in subjects with normal BMD was 0.67%, 0.47% and 1.87%, respectively; the long term in vivo precision error was 1.14%, 0.26% and 2.95%, respectively. No significant difference was found between BMD values on the right and left heel. A statistically significant correlation (p < 0.001) was found between BUA and BMD (r = 0.71), SOS and BMD (r = 0.73), Stiffness and BMD (r = 0.77). The heel BMD was also significantly correlated to BMD of the femoral neck (r = 0.64) and BMD of total femur (r = 0.70) and BMD of lumbar spine (r = 0.59). CONCLUSIONS: The DXA of the heel underestimates the prevalence of osteoporosis. The results of the heel QUS (Stiffness) appear to be better correlated to femoral BMD than heel BMD. The observed correlation coefficient of 0.77 between QUS and DXA at the heel was statistically significant, but it explains only 60% of variability of the QUS of the heel.

Absorptiometry, Photon↗
PubMed2005

Cardiac output measurement by pulse dye densitometry in cardiac surgery.

Summary The aim of this study was to compare the accuracy of pulse dye densitometry with that of bolus thermodilution cardiac output measurement in patients before and after elective coronary artery bypass grafting. Twenty-eight patients were studied. Agreement between mean thermodilution and pulse dye densitometry cardiac output values was assessed by Bland-Altman analysis. Preoperative median [range] cardiac output was 3.87 [2.37-6.0] l.min(-1) by thermodilution, and 3.11 [1.7-5.45] l.min(-1) by pulse dye densitometry using indocyanine green 5 mg. Pulse dye densitometry underestimated cardiac output (mean bias - 0.42 l.min(-1)); the limits of agreement were +/- 1.91 l.min(-1), and mean error was 50.3%, indicating low precision. Preoperative median [range] cardiac output was 3.85 [2.2-6.0] l.min(-1) for bolus thermodilution cardiac output and 4.2 [2.0-7.2] l.min(-1) for pulse dye densitometry using indocyanine green 20 mg. Mean bias was + 0.566 l.min(-1), the limits of agreement were +/- 2.51 l.min(-1) and mean error was 60.9%. Postoperative cardiac output data were not analysed because pulse dye densitometry signals were low or absent in > 50% of the patients. We conclude that pulse dye densitometry using indocyanine green 5 mg or 20 mg is inaccurate in anaesthetised patients before coronary artery bypass surgery and cannot be used after surgery because of a high incidence of low pulse dye densitometry signal amplitudes.

Aged↗
PubMed2000

Use of bone densitometry by Ontario family physicians.

A stratified (urban/rural), computer-generated random sample of 797 Ontario members of the College of Family Physicians of Canada received a self-administered questionnaire by mail. The questionnaire examined current use of bone densitometry, focusing on reasons for its use, factors that limit use, and features of the report that are helpful to the family physician in subsequent patient management. The response rate was 64% (457/711) after excluding 77 physicians who no longer practice family medicine. Ninety-two percent of the physicians used densitometry; of these, 97% ordered the test in the past year. Compared with urban physicians, rural physicians were more likely to 'never use densitometry' (p=0.04). Rural physicians who reported using densitometry used it less frequently (p=0.002), were less likely to have local access (p=0.001), and were less confident in its use (p=0.004) than their urban counterparts. Risk factors and hormone replacement therapy decision-making were ranked equally as the most frequent reasons for ordering the test, followed by follow-up. Few physicians identified limits to their use of densitometry. Female physicians used densitometry more frequently (p = 0.03) and were more confident in its use (p = 0.02). Features of the bone density report found to be most helpful were the statement of fracture risk, suggestions for further investigation, management and follow-up, and percent reduction in bone density compared with age-matched controls. The use of bone densitometry by Ontario family physicians is consistent with published guidelines. These physicians identified the estimate of fracture risk and suggestions for investigation and management as the most helpful features of the bone density report. This suggests a role for the incorporation of clinical data in bone density reporting.

Adult↗
PubMed2000

Patterns of medication use before and after bone densitometry: factors associated with appropriate treatment.

OBJECTIVE: We examined the medications used by women before and after bone densitometry to determine whether patient or physician factors were associated with appropriate osteoporosis therapy. METHODS: Appropriate osteoporosis treatment was defined as alendronate, etidronate, calcitonin, or hormone replacement therapy (HRT) for women with any bone mineral density (BMD) t score < -2.5 or no osteoporosis therapy, except HRT, for women with t scores > -1.0. We observed a cohort of women who underwent bone densitometry at one outpatient osteoporosis clinic. Medical history, medication use, and demographic data were collected at the time of bone densitometry. A followup questionnaire assessed the medication use patterns since bone densitometry and attitudes about osteoporosis therapy. RESULTS: We recruited 553 women who underwent bone densitometry in 1996. Their mean age was 62 years and 95% were postmenopausal. Prior to bone density scans, 27% of patients used HRT, 15% used bisphosphonates, and 6% used calcitonin. Scan results and surveys revealed that 40% of patients had BMD below a t score of -2.5 at any site. Of women with osteoporosis 78% reported taking an appropriate medication after their scans. Patients most likely to receive appropriate treatment were those who understood their bone densitometry results (odds ratio, OR, 2.5; 95% confidence interval, CI, 1.3 to 4.8) and patients who were taking an osteoporosis medication (OR 1.9; 95% CI 1.0 to 3.6). Neither the specialty of the referring physician nor patients' medical history was associated with use of appropriate osteoporosis therapy. CONCLUSION: Of women with osteoporosis who underwent bone densitometry 78% received appropriate therapy after this test. Patient factors were associated with the likelihood that they received appropriate therapy, suggesting that strategies aimed at educating patients may improve the use of osteoporosis medications.

Aged↗
PubMed1999

PROQUAD: accreditation program of the Brazilian society for clinical densitometry.

In 1996, the Brazilian Society for Clinical Densitometry (SBDens) developed an accreditation program to be applied to all densitometry centers, under the supervision of the certified physicians from SBDens. This program is named Programa Nacional de Qualidade em Densitometria (PROQUAD) and was developed to verify at least three aspects of the bone densitometry practice: the functioning of equipment, the methods used by technicians in performing the scans, and how the physicians are analyzing the scans and interpreting the results. From the 360 certified physicians who are members of SBDens, nearly one-third are participating in this program. The final purpose of PROQUAD is to provide approved centers with a seal, to be stamped on their examinations. The seal will signify to referring physicians, and the community, which centers are working under high standards of quality. It has been 2 yr since PROQUAD was established, and the data obtained confirm the improvement of quality in the practice of densitometry in Brazil. Any input from other societies that could improve PROQUAD is welcomed. Ensuring good densitometry practices is a goal for which all densitometry societies must strive.

Absorptiometry, Photon↗
PubMed1996

Bone densitometry at a district general hospital: evaluation of service by doctors and patients.

OBJECTIVE: To assess doctors' and patients' views about a district general hospital bone densitometry service and to examine existing practice to influence future provision. DESIGN: Three postal surveys: (a) of doctors potentially using the service, (b) of patients undergoing a bone densitometry test during a six month period, and (c) of the referring doctors of the patients undergoing the test. SETTING: Bone densitometry service at South Cleveland Hospital, Middlesbrough and two district health authorities: South Tees and Northallerton. SUBJECTS: All general practitioners (n=201) and hospital consultants in general medicine, rheumatology, obstetrics and gynaecology, orthopaedics, radio therapy and oncology, haematology, and radiology (n=61); all patients undergoing an initial bone densitometry test (n=309) during a six month period; and their referring doctors. MAIN MEASURES: Service awareness and use, knowledge of clinical indications, test results, influence of test results on patient management, satisfaction with the service and its future provision. RESULTS: The overall response rates for the three surveys were 87%, 70%, and 61%. There was a high awareness of the service among doctors and patients; 219(84%) doctors were aware and 155 of them (71%) had used it, and patients often (40%) suggested the test to their doctor. The test was used for a range of reasons including screening although the general use was consistent with current guidelines. Two hundred (65%) bone densitometry measurements were normal, 71(23%) were low normal, and 38(12%) were low. Although doctors reported that management of patients had been influenced by the test results, the algorithm for decision making was unclear. Patients and doctors were satisfied with the service and most (n=146, 68%) doctors wanted referral guidelines for the service. CONCLUSIONS: There was a high awareness of, use of, and satisfaction with the service. Patients were being referred for a range of reasons and a few of these could not be justified, many tests were normal, and clinical decision making was not always influenced by the test result. It is concluded that bone densitometry services should be provided but only for patients whose management will be influenced by test results and subject to guidelines to ensure appropriate use of the technology.

Absorptiometry, Photon↗