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PubMedDate not supplied

[Photon densitometry in the diagnosis of osteoporosis].

The increased average life expectancy of the inhabitants of industrialised countries has led to a marked increase in degenerative pathologies, including osteoporosis. This has made it necessary to elaborate instrumental tests capable of identifying risk subjects in order to intervene as quickly as possible using appropriate prophylactic and therapeutic measures. Single and dual photon ray densitometry represents the first correct approach to quantitatively assess bone mineral content. It not only allows an early diagnosis to be made but also enables a longitudinal study to be made of patients receiving treatment. The main studies on the accuracy and precision of dual photon ray densitometry are reported together with the authors' findings regarding the definition of the fracture threshold and osteoporosis caused by metabolic and endocrinological disorders.

Absorptiometry, Photon↗
PubMed1991

[DEXA (dual-energy x-ray absorptiometry) and DPA (dual photon absorptiometry) in densitometry of the femoral neck: correlation of the measurements of three commercially available instruments].

The bone mineral density measurements of three different instruments at the femoral head were compared using 12 cadaver specimens. Two of these instruments were operated by x-rays (dual energy x-ray absorptiometry = DEXA), whereas one system was based on a gadolinium source (dual photon absorptiometry = DPA). Although excellent correlation between the measurements was obtained (r greater than 0,9), the measurements of one of the DEXA-instruments were significantly higher than the measurements of the two other systems. We conclude that a comparison of bone mineral density measurements obtained on different densitometry instruments may pose problems. Follow-up examinations should be done on one single densitometry unit.

Absorptiometry, Photon↗
PubMed1990

[Digital bone densitometry. A routine method for evaluating and monitoring bone mineralization].

Digitalized bone densitometry is a simple technique for studying bone mineralization which can be performed during the radiological examination. Digitalized bone densitometry was used to estimate the bone mineral content of the third lumbar vertebra in 30 women and 16 men, the neck of the femur in 27 women and 20 men and the second metacarpal in 27 women and 17 men. The results were compared to the data provided by conventional methods. The appearance of the curves, the index of accuracy and reproducibility of the method suggest that it can be used to detect and monitor bone mineralization of patients for a moderate cost.

Absorptiometry, Photon↗
PubMed1990

[Computed serial densitometry of the tissue components of renal angiomyolipoma. A new radiohistologic method of in vivo pathologic diagnosis].

Computerised serial densitometry (CSD) of renal angiomyolipoma (AML) and its three tissue components was done in order to find out whether this procedure could help in differential diagnosis and provide better data for the understanding of AML presentation in CT imaging. It was found that AML detection in plain scan tomography requires a fat fraction of more than 50%. Angiomyolipomas with a fat fraction of less than 50% need computerised serial densitometry to enable differentiation from other unidentified tumours. The criteria to be used in these cases are 1) the low curve level and 2) the presence and slim shape of the initial circulatory peak. The principle of using standard densitometric curves of single tissue components and cells in in vivo tissue analysis might gain significance in the noninvasive, computerised qualitative and quantitative analysis of the composition of tumours and organs thus creating new possibilities for the diagnosis, follow-up and prognosis of diseases.

Hemangioma↗
PubMedDate not supplied

[Diagnosis of osteoporosis using dual photon densitometry].

Osteoporosis is often diagnosed after fracture occurrence, when therapy is less effective. The dual photon densitometry has been the proposed method for osteoporosis early diagnosis. In the present study is presented our experience on the lumbar vertebral and femoral neck bone mass measurement by utilizing a Lunar DP-3 densitometer in normal young 82 volunteers and 103 women with radiologically and clinically diagnosed osteoporosis. The values found in osteoporotical patients were significantly lower when compared to those normals either in lumbar vertebrae (L2-L4) or in the femoral neck. The method's coefficient of variation was less than 0.5%, when determinated with a synthetic phantom aid and less than 1.5% repeating the exam in 10 normal volunteers. These results show that dual photon densitometry is a simple, sensitive and non-invasible method for early diagnosis and therapeutic follow-up of osteoporotical patients.

Absorptiometry, Photon↗
PubMed1989

Densitometry of implanted allograft ear ossicles.

Densitometry measurements of allograft ear ossicles implanted in humans middles ears for more than 10 years have been performed by means of High Resolution Computerized Tomography and compared with similar measurements made in the opposite normal middle ear ossicles. Eight patients operated for unilateral chronic ear disease were selected for this study. Densitometry findings have been also correlated with histological observations made in allograft ossicles removed after a long-term implantation period.

Cholesteatoma↗
PubMed1989

Prediction of properties of fracture callus by measurement of mineral density using micro-bone densitometry.

UNLABELLED: An experiment was designed to determine whether the material properties of fracture callus can be predicted by the measurement of mineral density. Rat tibiae that had a closed fracture were used to obtain uniform specimens of fracture callus at sequential stages of healing. An in vitro indentation test was done and tissue was biopsied, using a trephine, to determine the hardness and calcium content of a standardized area of callus tissue. The hardness of the callus was correlated with the mineral density of the local tissue, which initially had been measured non-invasively with single-photon-based micro-bone densitometry. The progress of differentiation and remodeling of callus was determined by comparative planimetric and microradiographic analyses of tissue. Determinations of density showed a linear correlation with concentrations of a hydroxyapatite equivalent solution (r = 0.997, p less than 0.001), with the ash weight of control specimens of cortical-trabecular bone (r = 0.998, p less than 0.001), and with the calcium content (micrograms per cubic millimeter) of the fracture callus (r = 0.854, p less than 0.001). The hardness of the callus had a non-linear relationship (r = 0.959, p less than 0.005) with the mineral density per volume of tissue, as measured by micro-bone densitometry. CLINICAL RELEVANCE: The appearance of fracture callus on conventional radiographs is an important clinical finding in the assessment of fracture-healing. It is, however, an unreliable predictor of the strength of the union of the fracture. Three-dimensional imaging and quantification of bone mineral provide additional data about the quality and geometry of fracture callus. Our study showed that mineral content per unit of volume is a good index of hardness of the fracture callus. Thus, quantitative imaging may be useful clinically for monitoring fracture-healing.

Animals↗
PubMed1983

[Value of densitometry in the computer tomographic differentiation of paracranial space-occupying lesions. Experimental phantom studies and clinical evaluation].

Hardening of the beam is a major disturbing effect in densitometry close to the calotte. This phenomenon is demonstrated in a phantom, and its theoretical base is discussed. If possible sources of error are considered and reduced by means of appropriate measuring conditions, measurement of density will furnish useful additional data in CT examination. The value of CT densitometry is demonstrated via follow-up observations; after an operation of a glioma of the optic nerve, a child developed hygromas complicated by superinfection which subsequently became horny or calcified.

Absorptiometry, Photon↗
PubMed1995

[Osteoporosis and densitometry screening: preliminary results].

We have examined the bone densitometry with osteoradiometer (ORM) of 355 patients who came to the "Centre for Prevention, Diagnosis and Therapy of Osteoporosis" at the Israelitic Hospital of Rome. 144 patients, 141 females and 3 males, will be studied in the future because their densitometric values are lower than the values considered normal for age and sex. We have valued anamnestic data (age, menopause, pregnancies, excessive use of alcohol and smoke, sedentary habits), medical data hyperthyroidism, OCB, chronic diarrhoea) and surgical data (ovariectomy, thyroidectomy, gastro-duodenal resection, mastectomy) to have the correct outline of the patient situation before further researches and beginning the best medical therapy. For the prevention and screening of people "at risk" densitometry is irreplaceable both pre-clinical osteopeny, and for checking the effects of the therapy.

Adult↗
PubMed1996

[Attempt of helical CT densitometry for assessing regional pulmonary ventilation].

Pulmonary dynamic CT densitometry during steady-state breathing was recorded and analyzed using helical CT scan in 14 patients with obstructive disorders involving small and large airways, and 2 with restrictive lung disease. The data set of 7-second, continuous helical scan at constant table position were reconstructed as 35 one-second temporarily overlapping images at 0.2- second intervals over 2-3 respiratory cycles, and regional CT densitometry was displayed. Normal lungs (5 volunteers) showed a regular sinusoidal curve, and maximal lung density change (LDC) was greater independent lungs than in independent lungs, with an average difference of 29.5 HU, indicating the gravitational effect In contrast, a regular sinusoidal curve was not shown in obstructive disorders, and a significant reduction in maximal LDC (33.7 +/- 22.6 HU) compared with the normal lungs (60.8 +/- 25.9 HU) (P < 0.001) was indicated. In contrast, no marked reduction in maximal LDC (53.7 +/- 28.6 HU) was shown in restrictive disorders. This method is fast and easy, and appears useful for the detection of ventilation abnormalities in obstructive lung disorders.

Absorptiometry, Photon↗
PubMed1997

[Advances in DPX densitometry].

The author provides information on modern densitometric examinations and their development in the past three decades. He analyses in brief the possibilities of densitometry on the basis of the double x-ray absorptiometry on the basis of his own experience and data gained from literature. The current standard software equipment includes the measurement of the lumbal PA projection, lumbal lateral, coxae PA and entire body PA. The apparatus detects the quantity of minerals in bones in form of BMC (bone mineral content) and BMD (bone mineral density) values, and compares the measured values of density with the average values in the healthy population. It automatically evaluates statistical values of the Z and T score. The bone density can be measured with the accuracy of 3-5%, the error of reproducibility is 1-2%. The apparatus represents an ideal equipment for the measurement of bone density under normal anatomic conditions of the skeleton and in early stages of the disease which is manifestant by changes in bone tissue. As soon as the condition includes deformations of the skeleton and osteoproductive changes, especially osteochondrosis, spondylosis and the presence of osteophytes, the result becomes inaccurate. The study drafts the trend in densitometry in frame of therapeutic, preventive and research activities in orthopaedics. (Fig. 4, Ref. 16.)

Absorptiometry, Photon↗
PubMed1997

[An attempt to assess the effect of stress in the femoral bone after implantation of the Weller endoprosthesis on changes within bone tissue in correlation with densitometry examination].

The paper presents comparative analysis of stress distribution, determined by finite elements method in normal femoral bone and one after Weller total hip replacement, with Gruen zones in consideration. An attempt to correlate an effort and bone tissue state has been made. The results of computer simulation have been compared with results of densitometry. It was found, that alloplasty unloads bone tissue along the stem and particularly around trochanteric area. Dual energy X-ray densitometry performed 7 days, 6 and 12 months after surgery revealed decreased BMC and BMD values in all analyzed zones. The greatest decrease was noted in zone 7.1 and 6.

Absorptiometry, Photon↗
PubMed1998

[Ultrasound densitometry of the heel bone in a random sample of the adult Czech population].

To assess the state of the skeleton of 870 subjects selected at random the authors used ultrasound densitometry of the talus. The assessment was made using a Cuba Clinical apparatus (McCue Ultrasonic Ltd.UK). The assessed parameters were BUA in db/MHz (broad band ultrasound attenuation) and VOS in m/s (velocity of sound). From the results it is apparent that the BUA values in men reach their peak at the age of 31-35 years. In women the BUA values are highest between 18 and 20 years, then follows a decline and again a rise between 41 and 45 years. The VOS values in men are highest between 18 and 20 years, followed by a drop and slight increase between 56 and 60 years. In women the VOS values reach their maximum between 18 and 20 years. The assessed values obtained in a random sample of the population from three regions are the basis for evaluation of bone densitometry obtained by means of questionnaire in the adult Czech population.

Adult↗
PubMed1998

Impact of carrier status determination for Duchenne/Becker muscular dystrophy by computer-assisted laser densitometry.

Carrier status determination for Duchenne and Becker muscular dystrophies (D/BMD), disorders caused by mutations in the dystrophin gene at Xp21, is complicated by a number of factors. These include a high mutation rate and a 5-10% recombination frequency across the dystrophin gene. For these reasons, linkage analysis frequently gives an inconclusive result, and a direct mutation detection method for females at risk is desirable. Because 65% of the mutations that cause D/BMD are deletions of one or more exons of the dystrophin gene, diagnosis in most affected males is relatively easy using multiplex polymerase chain reaction (PCR) analysis. However, deletion analysis in females is more difficult because of the interference of the normal X chromosome in the deletion assay. We have developed a quantitative PCR-based analysis designated computer-assisted laser densitometry (CALD), which uses the automated fluorescent fragment analysis application of the Applied Biosystems (Foster City, California) automated sequencer. This method has proved to be 100% accurate in retrospective blind studies analysing a total of 351 samples. Subsequent analysis of more than 800 women from more than 400 D/BMD families has shown that a highly accurate carrier risk can be given in more than 90% of cases.

Densitometry↗
PubMed2002

Fully reversible procedure for silver staining improves densitometry of complex mixtures of biopolymers resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

Due to its high sensitivity, silver staining is a widely popular method for the revelation of biopolymers separated by both native and denaturing electrophoresis. A step-by-step method for the destaining and restaining of overdeveloped/overloaded silver-stained bands is described that is applicable to both proteins and nucleic acids. The procedure significantly improves densitometric analysis of gels that have been silver stained with either commercial kits or solutions made in-house. The method permits reproducible densitometry of silver-stained gels and allows quantification of both main and minor components in complex mixture of molecules resolved on the same gel slab. All steps may be interrupted and are readily reversible, allowing for facile densitometric analyses and photographic recording under optimized conditions. Furthermore, common artifacts such as differential staining of the two gel surfaces, localized uneven yellow-ochre background, and the presence of fold marks and fingerprints can be easily removed.

Artifacts↗
PubMed2004

Quality assessment for tramadol in pharmaceutical preparations with thin layer chromatography and densitometry.

Research studies have been carried out to develop a chromatographic and densitometric method suitable for identification and determination of tramadol and impurities. In addition, the stability of tramadol in solutions was investigated, including an effect of solution pH, temperature and incubation time. In the first instance the conditions for identification and quantitative determination of tramadol and impurities in pharmaceutical preparations were established. The separation was performed on silica gel-coated chromatographic plates (HPTLC) using two mobile phases: (I) chloroform-methanol-glacial acetic acid (9:2:0.1, v/v/v); (II) chloroform-toluene-ethanol (9:8:1, v/v/v). The UV densitometry was carried out at lambda = 270 nm. The developed method is of high sensitivity and low detection and determination limits ranging from 0.044 to 0.35 microg. For individual constituents the recovery ranges from 93.23 to 99.66%. The next step was to evaluate the stability of tramadol and determine a method of decomposition under various experimental conditions. It was found that tramadol decomposes in various ways in acidic and basic environments producing (1RS)-[2-(3-methoxyphenyl)cyclohex-2-enyl]-N,N-dimethylmethanamine (imp. B) and (1RS, 2RS)-2-[(dimethylamino)methyl]-1-(3-methoxyphenyl)cyclohexanol (imp. cis-T) or imp. cis-T, respectively.

Analgesics, Opioid↗
PubMed1996

On-line evaluation of systolic performance by densitometry in digital left ventriculography.

The angiocardiographic evaluation of left ventricular end-diastolic (LVEDV) and end-systolic (LVESV) volumes and ejection fraction (EF) is routinely performed by the area-length method (ALM) but may lead to erroneous results. Digital imaging in real time allows densitometric procedures of determining left ventricular (LV) performance to be applied alternatively. In this study, we present densitometric algorithms for the analysis of LVEDV, LVESV, and EF from digital image data, establish accuracy and reproducibility, and determine value and limitations in comparison with ALM in single-plane 30 degrees right anterior oblique (RAO) projection. A linear relationship between iodine depth and measured densities is mainly burdened with scatter radiation and beam hardening which reduce primary radiation and suppress iodine depth. However, facilities such as deconvolution and correction algorithms are capable of reducing these sources of error. In the present study, computer-analyzed contrast images of iodine-filled wedges and spheres showed a near-linear relationship between iodine depth between 50-100 mg/cm2 and measured densities. Contrast images of heart casts and LV angio-grams of 54 patients were obtained with a digital image acquisition and processing system, and evaluated by two independent observers. The phantom study resulted in significantly (p < or = 0.01) better densitometric standard errors of estimate for volumes [3.3 ml densitometry (DENS) vs. 8.9 ml (ALM)] and simulated EF [4.3% (DENS) vs. 7.8% (ALM)] than ALM. The standard error of estimate for the comparison between both methods was 8.4 ml for volumes and 7.5% for EF. Densitometric volumes tended to underestimate volumes calculated by ALM. The angiographic study of patients demonstrated significant correlations between both methods (LVEDV r = 0.78, LVESV r = 0.83, total volumes: r = 0.89; EF r = 0.88). The standard errors of estimate can be ascribed to systematic, method-related errors of both DENS and ALM (LVEDV +/- 28.9 ml, LVESV +/- 23.4 ml, total volumes (EDV and ESV) +/- 27.1 ml; EF +/- 8.1%). The intra- and interobserver variability, respectively, exhibited significantly smaller (p < or = 0.01 and p < or = 0.05, respectively) standard errors of estimate for densitometric EF [4.6% (DENS) vs. 8.5% (ALM) and 7.1% (DENS) vs. 10.3% (ALM), respectively]. Inclined but not significant differences were found for LVEDV and LVESV. In conclusion, the data presented indicate that the calculation of LV volumes and EF in digital left ventriculography may be performed accurately by densitometric calculation in single-plane 30 degrees RAO projection. Minor underestimations in densitometric volume determination may be anticipated in the evaluation of LV geometry.

Adult↗
PubMed1988

Wheat cultivar identification by a totally automatic soft-laser scanning densitometry and computer-aided analysis of protein electropherograms.

A computer-aided analysis based on soft-laser densitometry of electrophoretic patterns is described. The system has the potential to automatically identify wheat cultivars from normalized sodium dodecyl sulfate-polyacrylamide gel electropherograms. The principle encompasses autocalibration of the relative mobilities of components of the unknown pattern using standards of Mr that bracket each pattern on the pictures, automatic identification of peaks and baseline correction, and simplified estimation of the peak intensities. The algorithm provides a normalized array that can be automatically compared with a library of standard cultivar patterns in order to determine those having the highest similarity percentage. The outputs of the program are 1) relative similarity plots which show the percentage of similarity between the unknown cultivar to that of each of the common standard cultivars put in a pattern library, 2) the names of cultivars in the library having the most similar patterns and 3) computer-generated electrophoretic graphics of these cultivars. This system is not intended to identify closely related cultivars but it is particularly recommended for cultivar identification without well-trained personnel, familiar with band location and nomenclature.

Densitometry↗