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Sample records for computerized tomography applied

  1. Computerized tomography. Yesterday and today

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    Ethier, R.; Melanson, D. (Montreal Neurological Inst., Quebec (Canada))

    1983-10-01

    This presentation describes the evolution of computerized tomography over the past decade and its contribution to the radiologic investigation of neurologic disorders. This new technique has not only stimulated development in the diagnosis of cerebral diseases, but the whole body as well. Detailed investigation of the spine, spinal cord, sella turcica, the orbits, as well as the petrous pyramids has been made possible through the development of high resolution scanning.

  2. Scintillation detectors in computerized tomography

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    Gilar, O.; Pavlicek, Z.; Jursova, L. (Tesla, Premysleni (Czechoslovakia). Vyzkumny Ustav Pristroju Jaderne Techniky)

    1984-07-01

    A new scintillator, Bi/sub 4/Ge/sub 3/O/sub 12/ (BGO), was tested for use in the detection part of computerized tomographs. In comparison with the NaI(Tl) scintillator it has a three-fold mass stopping power and allows the detection of medium and high energy gamma radiation with a higher detection efficiency, i.e., for the same detection efficiency its size is much smaller. Some other mechanical, physical and optical parameters of the BGO scintillator are given. BGO is prospective for use in high energy spectrometry and may replace NaI(Tl) wherever the following parameters are significant: crystal size, detection efficiency for gamma radiation, and good spatial resolution.

  3. Anti-3-[18F]FACBC Positron Emission Tomography-Computerized Tomography and 111In-Capromab Pendetide Single Photon Emission Computerized Tomography-Computerized Tomography for Recurrent Prostate Carcinoma: Results of a Prospective Clinical Trial

    Science.gov (United States)

    Schuster, David M.; Nieh, Peter T.; Jani, Ashesh B.; Amzat, Rianot; Bowman, F. DuBois; Halkar, Raghuveer K.; Master, Viraj A.; Nye, Jonathon A.; Odewole, Oluwaseun A.; Osunkoya, Adeboye O.; Savir-Baruch, Bital; Alaei-Taleghani, Pooneh; Goodman, Mark M.

    2014-01-01

    Purpose We prospectively evaluated the amino acid analogue positron emission tomography radiotracer anti-3-[18F]FACBC compared to ProstaScint® (111In-capromab pendetide) single photon emission computerized tomography-computerized tomography to detect recurrent prostate carcinoma. Materials and Methods A total of 93 patients met study inclusion criteria who underwent anti-3-[18F]FACBC positron emission tomography-computerized tomography plus 111In-capromab pendetide single photon emission computerized tomography-computerized tomography for suspected recurrent prostate carcinoma within 90 days. Reference standards were applied by a multidisciplinary board. We calculated diagnostic performance for detecting disease. Results In the 91 of 93 patients with sufficient data for a consensus on the presence or absence of prostate/bed disease anti-3-[18F]FACBC had 90.2% sensitivity, 40.0% specificity, 73.6% accuracy, 75.3% positive predictive value and 66.7% negative predictive value compared to 111In-capromab pendetide with 67.2%, 56.7%, 63.7%, 75.9% and 45.9%, respectively. In the 70 of 93 patients with a consensus on the presence or absence of extraprostatic disease anti-3-[18F]FACBC had 55.0% sensitivity, 96.7% specificity, 72.9% accuracy, 95.7% positive predictive value and 61.7% negative predictive value compared to 111In-capromabpendetide with10.0%, 86.7%, 42.9%, 50.0% and 41.9%, respectively. Of 77 index lesions used to prove positivity histological proof was obtained in 74 (96.1%). Anti-3-[18F]FACBC identified 14 more positive prostate bed recurrences (55 vs 41) and 18 more patients with extraprostatic involvement (22 vs 4). Anti-3-[18F]FACBC positron emission tomography-computerized tomography correctly up-staged 18 of 70 cases (25.7%) in which there was a consensus on the presence or absence of extraprostatic involvement. Conclusions Better diagnostic performance was noted for anti-3-[18F]FACBC positron emission tomography-computerized tomography than for 111In

  4. Computerized tomography in evaluation of hepatic neoplasms

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    Luna, R.F.; Resende, C.; Tishler, J.M.A.; Aldrete, J.S.; Shin, M.S.; Rubin, E.; Rahn, N.H.

    1984-08-01

    The authors reviewed their experience with computerized tomography (CT) of the abdomen in 212 patients with histologically documented liver neoplasms seen during a 30-month period. The CT findings in cavernous hemangioma and focal nodular hyperplasia were specific, and permitted accurate diagnosis of this lesion before biopsy. The CT appearance of all other lesions was variable. CT is useful in providing an accurate evaluation of the intrahepatic and extrahepatic extent of the neoplasm.

  5. Computerized tomography using a modified orthogonal tangent correction algorithm.

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    Hsia, T C; Smith, S C; Lantz, B M

    1976-10-01

    A modified orthogonal tangent correction algorithm is presented for computerized tomography. The algorithm uses four X-rays scans spaced 45 degrees apart, to reconstruct a transverse axial image. The reconstruction procedure is interative in which image matrix elements are corrected by alternately matching the two sets of orthogonal scan data. The algorithm has been applied to phantom data as well as to video recorded fluoroscopic data.

  6. Combined single photon emission computerized tomography and conventional computerized tomography: Clinical value for the shoulder surgeons?

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    Michael T Hirschmann

    2011-01-01

    Full Text Available With the cases described, we strive to introduce single photon emission computerized tomography in combination with conventional computer tomography (SPECT/CT to shoulder surgeons, illustrate the possible clinical value it may offer as new diagnostic radiologic modality, and discuss its limitations. SPECT/CT may facilitate the establishment of diagnosis, process of decision making, and further treatment for complex shoulder pathologies. Some of these advantages were highlighted in cases that are frequently seen in most shoulder clinics.

  7. Computerized axial tomography in clinical pediatrics.

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    McCullough, D C; Kufta, C; Axelbaum, S P; Schellinger, D

    1977-02-01

    Computerized axial tomography (CAT), a noninvasive radiologie method, provides a new dimension in screening and diagnosis of intracranial pathology. Evaluation of 725 scans in infants and children demonstrates that CAT may be performed with negligible risk, although sedation and restraint are essential to the successful performance of studies in children under 6 years of age. CAT is the preferred initial diagnostic method in suspected hydrocephalls and is accurate in the detection and precise localization of brain tumors. The management of hydrocephalus and brain tumors has been significantly altered by the availability of CAT. Few invasive neuroradiologic procedures are required and pneumography is especially curtailed. Serial scanning is the best available method of monitoring ventricular alterations in hydrocephalus, tumor size during radiotherapy or chemotherapy, and postoperative recurrence of benign neoplasms. Complex intracranial anomalies are detectable with computerized tomography, but complete definition of pathology often requires angiography and air studies. Limited clinical experience in detecting neonatal intraventricular hemorrhage suggests that CAT will be a valuable tool for futlre investigations of that problem.

  8. [Diagnosis of toxic lesions of the brain using computerized tomography].

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    Bushev, I I; Karpova, M N; Tskhovrebov, T M

    1990-01-01

    X-ray computerized tomography was used to examine the brain in 39 patients aged 14 to 39 years with different experience of using volatile narcotically acting substances. The discovered alterations make it possible to appraise the influence of toxic substances and the degree of brain atrophy, which attests to the diagnostic value of computerized tomography in patients with toxicomanias.

  9. Computerized tomography in acute and chronic pancreatitis

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    Kalmar, J.A.; Matthews, C.C.; Bishop, L.A.

    1984-11-01

    Modern imaging techniques have revolutionized the diagnostic evaluation of pancreatitis, primarily demonstrating its complications. Computerized tomography (CT) is a more sensitive method than ultrasonography and pancreatic ductography. A chart review revealed 214 patients at our hospital with a discharge diagnosis of pancreatitis. Sixty patients had CT for evaluation of possible complications. Only five scans were normal. Of 37 cases of acute pancreatitis, 92% demonstrated localized or diffuse enlargement, and 65% showed loss of pancreatic outline. Other frequent findings included thickening of perirenal fascia (49%), ileus (43%), edema of mesentery (35%), and inflammatory exudate (32%). Abscess and pseudocyst were each detected in 8% of cases. In chronic pancreatitis 65% of patients showed localized or diffuse pancreatic enlargement. Atrophy of the gland (30%), calcification (30%), pseudocyst (26%), and dilated pancreatic ducts (17%) were also seen. CT is effective in evaluating pancreatitis and its complications. 14 references, 5 figures, 2 tables.

  10. Organ doses from computerized tomography examinations

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    Janeczek, J.

    1995-12-31

    Estimates of mean organs doses from five typical computerized tomography (CT) examinations were obtained. Measurements were done using Rando-Alderson anthropomorphic phantom and thermoluminescent dosemeters (TLD). Radiation dose distributions within a phantom has been measured for each examination and results were used for organ dose calculation. Doses to organs specified by ICPR 60 Recommendations were measured for five CT scanners (CT/T8800, CT 9800, CT MAX - made by General Electric; CT 1200 SX - made by Picker; SOMATOM 2 - made by Siemens). Dose distributions from scattered radiation were measured and indicate that scattered radiation dose to thyroid and eye lens can be reduced by proper examination limits setting. The lowest mean organ doses were obtained from CT/T8800 scanner. More advanced scanners using high intensity continuous radiation were giving higher organ doses. (author). 23 refs, 6 figs, 13 tabs.

  11. Computerized ionospheric tomography with the IRI model

    Science.gov (United States)

    Arikan, Orhan; Arikan, Feza; Erol, Cemil B.

    Computerized ionospheric tomography (CIT) is a method to estimate ionospheric electron density distribution by using the global positioning system (GPS) signals recorded by the GPS receivers. Ionospheric electron density is a function of latitude, longitude, height and time. A general approach in CIT is to represent the ionosphere as a linear combination of basis functions. In this study, the model of the ionosphere is obtained from the IRI in latitude and height only. The goal is to determine the best representing basis function from the set of Squeezed Legendre polynomials, truncated Legendre polynomials, Haar Wavelets and singular value decomposition (SVD). The reconstruction algorithms used in this study can be listed as total least squares (TLS), regularized least squares, algebraic reconstruction technique (ART) and a hybrid algorithm where the reconstruction from the TLS algorithm is used as the initial estimate for the ART. The error performance of the reconstruction algorithms are compared with respect to the electron density generated by the IRI-2001 model. In the investigated scenario, the measurements are obtained from the IRI-2001 as the line integral of the electron density profiles, imitating the total electron content estimated from GPS measurements. It has been observed that the minimum error between the reconstructed and model ionospheres depends on both the reconstruction algorithm and the basis functions where the best results have been obtained for the basis functions from the model itself through SVD.

  12. Computerized ionospheric tomography based on geosynchronous SAR

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    Hu, Cheng; Tian, Ye; Dong, Xichao; Wang, Rui; Long, Teng

    2017-02-01

    Computerized ionospheric tomography (CIT) based on spaceborne synthetic aperture radar (SAR) is an emerging technique to construct the three-dimensional (3-D) image of ionosphere. The current studies are all based on the Low Earth Orbit synthetic aperture radar (LEO SAR) which is limited by long repeat period and small coverage. In this paper, a novel ionospheric 3-D CIT technique based on geosynchronous SAR (GEO SAR) is put forward. First, several influences of complex atmospheric environment on GEO SAR focusing are detailedly analyzed, including background ionosphere and multiple scattering effects (induced by turbulent ionosphere), tropospheric effects, and random noises. Then the corresponding GEO SAR signal model is constructed with consideration of the temporal-variant background ionosphere within the GEO SAR long integration time (typically 100 s to 1000 s level). Concurrently, an accurate total electron content (TEC) retrieval method based on GEO SAR data is put forward through subband division in range and subaperture division in azimuth, obtaining variant TEC value with respect to the azimuth time. The processing steps of GEO SAR CIT are given and discussed. Owing to the short repeat period and large coverage area, GEO SAR CIT has potentials of covering the specific space continuously and completely and resultantly has excellent real-time performance. Finally, the TEC retrieval and GEO SAR CIT construction are performed by employing a numerical study based on the meteorological data. The feasibility and correctness of the proposed methods are verified.

  13. Radation distribution in head & thorax computerized tomography

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    Mohammad Mahdavi

    2014-05-01

    Full Text Available Background: Determination of the exposure levels in the computerized tomography (CT practices is necessary to define the respected national reference levels, quality control of CT centers and the risk assessment for radiation induced cancers. Material and Methods: On the basis of this necessity, the radiation exposure distribution due to common CT practices has been investigated at Razi Hospital CT center in Rasht using tissue-equivalent phantoms and the thermoluminescent dosimeters (TLD. The Head and Thorax phantoms were used with the standard dimensions incorporating holes at the center and edges for TLD placement. Dosimetry was carried out using LiF Mg, Cu, P small chips due to their relatively tissue equivalence, high sensitivity convenient annealing procedure and the non-complex glow curve. Results: Results showed that CTDI for Head is 52.85 mGy and for Body is 68.15mGy. CTDLW for Head is 13.67 mGy and for Body is 16.94mGy . Conclusion: In comparison with other radiographical procedures, patient absorbed doses in CT imaging are usually very high. Content of dose is increased by increase of mAs.

  14. Computerized tomography used as a routine procedure at postmortem investigations

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    Leth, Peter Mygind

    2009-01-01

    This is a prospective investigation of a consecutive series of 250 deceased individuals who were computerized tomography (CT)-scanned and autopsied. In 13% of patients, important findings at the CT-scanning were not found at the autopsy, and in 48% of patients, important autopsy findings were...

  15. Morphological analysis of the vestibular aqueduct by computerized tomography images

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    Marques, Sergio Ricardo [Morphology and Genetics Department, Sao Paulo Federal University-Paulista Medical School, Disciplina de Anatomia Descritiva e Topografica, Rua Botucatu, 740-Edificio Leitao da Cunha, CEP 04023-900, Vila Clementino, Sao Paulo (Brazil)]. E-mail: sergioanat.morf@epm.br; Smith, Ricardo Luiz [Morphology and Genetics Department, Sao Paulo Federal University-Paulista Medical School, Disciplina de Anatomia Descritiva e Topografica, Rua Botucatu, 740-Edificio Leitao da Cunha, CEP 04023-900, Vila Clementino, Sao Paulo (Brazil); Isotani, Sadao [Institute of Physics, University of Sao Paulo, Sao Paulo (Brazil); Alonso, Luis Garcia [Morphology and Genetics Department, Sao Paulo Federal University-Paulista Medical School, Disciplina de Anatomia Descritiva e Topografica, Rua Botucatu, 740-Edificio Leitao da Cunha, CEP 04023-900, Vila Clementino, Sao Paulo (Brazil); Anadao, Carlos Augusto [Otorhinolaryngology Department, Sao Paulo Federal University-Paulista Medical School, Sao Paulo (Brazil); Prates, Jose Carlos [Morphology and Genetics Department, Sao Paulo Federal University-Paulista Medical School, Disciplina de Anatomia Descritiva e Topografica, Rua Botucatu, 740-Edificio Leitao da Cunha, CEP 04023-900, Vila Clementino, Sao Paulo (Brazil); Lederman, Henrique Manoel [Image Diagnosis Department, Sao Paulo Federal University-Paulista Medical School, Sao Paulo (Brazil)

    2007-01-15

    Objective: In the last two decades, advances in the computerized tomography (CT) field revise the internal and medium ear evaluation. Therefore, the aim of this study is to analyze the morphology and morphometric aspects of the vestibular aqueduct on the basis of computerized tomography images (CTI). Material and method: Computerized tomography images of vestibular aqueducts were acquired from patients (n = 110) with an age range of 1-92 years. Thereafter, from the vestibular aqueducts images a morphometric analysis was performed. Through a computerized image processing system, the vestibular aqueduct measurements comprised of its area, external opening, length and the distance from the vestibular aqueduct to the internal acoustic meatus. Results: The morphology of the vestibular aqueduct may be funnel-shaped, filiform or tubular and the respective proportions were found to be at 44%, 33% and 22% in children and 21.7%, 53.3% and 25% in adults. The morphometric data showed to be of 4.86 mm{sup 2} of area, 2.24 mm of the external opening, 4.73 mm of length and 11.88 mm of the distance from the vestibular aqueduct to the internal acoustic meatus, in children, and in adults it was of 4.93 mm{sup 2}, 2.09 mm, 4.44 mm, and 11.35 mm, respectively. Conclusions: Computerized tomography showed that the vestibular aqueduct presents high morphological variability. The morphometric analysis showed that the differences found between groups of children and adults or between groups of both genders were not statistically significant.

  16. Rhinoorbitocerebral mucormycosis. A case study utilizing computerized tomography examination

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    Prando, D. (Hospital Sirio-Libanes, Sao Paulo (Brazil)); Clemente Filho, A.S.; Secaf, F. (Escola Paulista de Medicina, Sao Paulo (Brazil))

    Rhinoorbitocerebral mucormycosis is a very serious and frequently fatal disease in which accurate analysis will often suggest the diagnosis. The Computerized Tomography (CT) scans are very helpful to establish the early diagnosis of mucormycosis and in the clear demonstration of the typical relationship between the sinus, orbital and cerebral disease. The recognition of the characteristic pattern in the involved areas should be helpful to early diagnosis and surgical treatment. The findings in one patient with craniofacial mucormycosis who underwent five times to CT examination are presented. Special attention is given to the serial CT scans and in the rapid spread to the central nervous system.

  17. Findings of psychopathology and computerized tomography in neuropsychiatric diseases

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    Gross, G.; Huber, G.; Schuettler, R.

    1982-08-01

    1978-1980 we examined 451 patients of the Psychiatric University Clinic of Bonn by computerized tomography. From 260 patients with characterized diseases of the brain and brain damages, 78 patients had neuropsychiatric diseases of old age, i.e. cerebro-vascular processes (average age of 63.7 years) and 9 patients had primary degenerative processes of the brain (average age of 62.1 years). Patients with diseases of the cerebral vessels showed irreversible psychopathological syndromes in 87%. The rate of pathological findings in CT increases in relation to degree of severity of the chronic (irreversible) organic psychosyndromes from 76% in pseudoneurasthenics syndromes to 93% in patients with organic changes of personality and to 100% in patients with dementia. The ambiguity of the conception of the multi-infarct-dementia is discussed. Only 19% of the sample with irreversible psychopathological changes showed localized neurological deficits and infarctions in CT, but none of them more than one. In all patients with dementia a cortical atrophy was found. There is a significant positive correlation between cerebral atrophy in CT and irreversible organic psychosyndrome. These findings with computerized tomography demonstrate in accordance with earlier pneumoencephalographic findings that distinct types of irreversible psychosyndromes can be correlated to distinct types of cerebral atrophy. But these statistical correlations between the degree of the severity of the loss of psychic functions and the reduction of cerebral tissue are not necessarily valid for any single case.

  18. Differential diagnosis in computerized tomography. 2. rev. and enl. ed.; Differenzialdiagnosen in der Computertomografie

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    Burgener, Francis A.; Meyers, Steven P. [Rochester Univ., NY (United States). Dept. of Imaging Sciences; Herzog, Christopher [Rotkreuzklinikum Muenchen (Germany); Zaunbauer, Wolfgang [Kantonsspital St. Gallen (Switzerland). Inst. fuer Radiologie

    2013-02-01

    The book on differential diagnosis in computerized tomography is aimed to support radiologists and physicians with experience concerning the interpretation of computerized tomography images by detailed descriptions of CT diagnoses. The book covers the following topics: intracranial indications, head and neck, spinal cord, muscle-skeleton system, thorax, abdomen and pelvis.

  19. Detection of drugs and explosives using neutron computerized tomography and artificial intelligence techniques

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    Ferreira, F.J.O. [Instituto de Engenharia Nuclear, Cidade Universitaria, Rio de Janeiro, CEP 21945-970, Caixa Postal 68550 (Brazil)], E-mail: fferreira@ien.gov.br; Crispim, V.R.; Silva, A.X. [DNC/Poli, PEN COPPE CT, UFRJ Universidade Federal do Rio de Janeiro, CEP 21941-972, Caixa Postal 68509, Rio de Janeiro (Brazil)

    2010-06-15

    In this study the development of a methodology to detect illicit drugs and plastic explosives is described with the objective of being applied in the realm of public security. For this end, non-destructive assay with neutrons was used and the technique applied was the real time neutron radiography together with computerized tomography. The system is endowed with automatic responses based upon the application of an artificial intelligence technique. In previous tests using real samples, the system proved capable of identifying 97% of the inspected materials.

  20. Assessment of computerized tomography devices in Minas Gerais state, Brazil

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    Oliveira, Paulo Marcio C., E-mail: pmco@cdtn.br, E-mail: ambienttal@ambienttal.com.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Horta, Mara Alice Avelar Saraiva [Faculdade Sao Camilo de Minas Gerais - FASC - MG, Graduacao de Tecnologia em Radiologia (Brazil); Santana, Priscila do Carmo [Programa de Pos Graduacao em Ciencias e Tecnicas Nucleares - PCTN, Universidade Federal de Minas Gerais (UFMG) Belo Horizonte, MG (Brazil); Magalhaes, Marcos Juliano [Ambienttal Protecao Radiologica Ltda., Belo Horizonte, MG (Brazil)

    2011-07-01

    Computed Tomography (CT) is the diagnostic imaging method most commonly performed today. It is a device that is undergoing a technological evolution and their quality control is sorely needed. The image quality evaluation process allow a better diagnosis and control of the patient dose received during image acquisition. The CT doses are higher than other X-ray examination techniques, like a conventional X-ray. Performance evaluation of computed tomography in Minas Gerais is not significant. Therefore, this work aims to analyze 20 CT equipment in Minas Gerais, with parameters according to the national regulatory agency (ANVISA - Agencia Nacional de Vigilancia Sanitaria) in twelve quality control tests. Sixty five percent (65%) of CT equipment evaluated showed excellent results and were not disapproved in any of the tests performed and 30% had failed in only one of the twelve tests performed. The worst result was found in the CT scanners in the test that evaluates the low contrast resolution, where 20% of CT showed non-compliance, followed by the test that evaluates the x-rays collimation beam, where 15% had failed. The tests allowed us to observe that the twenty computerized tomography equipment achieved a great pass rate. Considering that the evaluated CTs performed the quality control tests for the first time, it is concluded that the equipment used in clinics and hospitals are of good quality image and low radiation doses. (author)

  1. Computerized tomography analysis of aceptic necrosis of the femoral head

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    Ichioka, Yoshiaki; Masuda, Takeshi; Matsuno, Takeo; Hasegawa, Isao; Sugano, Hiroki; Konno, Takushi.

    1988-03-01

    Computerized tomography (CT) findings of the normal femoral head in 14 patients with unilateral aceptic necrosis of the femoral head (ANF) and in healthy adults were analyzed for early diagnostic significance. CT appearance of the bone trabeculae fell into normal finding, diffuse sclerosis, and mottled sclerosis. The development of necrosis during the process was accompanied by diffuse sclerosis, suggesting that diffuse sclerosis is an early CT appearance in the case of ANF. In a three-dimensional quantification of the necrotic area for 20 patients before rotational osteotomy of the femoral head, deformation of the femoral head after the surgery was found to frequently result from 50 % or more of the necrotic area in the femoral head, irrespective of the size of necrosis on the surface of the femoral head. This suggested the influence of the three-dimensional spread of necrosis on the intensity of the femoral head. (Namekawa, K.).

  2. Cranial computerized tomography and cerebral angiography in diagnosis of infarction

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    Zuelich, K.J.

    1988-08-05

    Discussion of the radiological means to further analysis of the pathogenesis of cerebrovascular alterations up to real stroke with infarction. Today in the first place computer-tomography even with contrast means, moreover in the form of 'angio-CT' are used. Localization, size, form, and the grade of tissue destruction may be analyzed. Furthermore perifocal edema and the stage as also the effect of vascular anastomoses for a collateral circulation may be evaluated. Invasive angiography with puncture of carotid and vertebral arteries is used only in special rare indications. Instead, digital computerized angiography (DSA) can be adopted if particular interest is in the study of intracranial arteries, even with an 'invasive' approach, e.g. by femoral catheter (Seldinger). In summarizing: For the analysis of particular problems radiological methods may assist diagnosis and therapy of cerebrovascular infarct.

  3. Computerized Tomography with Total Variation and with Shearlets

    CERN Document Server

    Garduño, Edgar

    2016-01-01

    To reduce the x-ray dose in computerized tomography (CT), many constrained optimization approaches have been proposed aiming at minimizing a regularizing function that measures lack of consistency with some prior knowledge about the object that is being imaged, subject to a (predetermined) level of consistency with the detected attenuation of x-rays. Proponents of the shearlet transform in the regularizing function claim that the reconstructions so obtained are better than those produced using TV for texture preservation (but may be worse for noise reduction). In this paper we report results related to this claim. In our reported experiments using simulated CT data collection of the head, reconstructions whose shearlet transform has a small $\\ell_1$-norm are not more efficacious than reconstructions that have a small TV value. Our experiments for making such comparisons use the recently-developed superiorization methodology for both regularizing functions. Superiorization is an automated procedure for turning...

  4. Computerized Tomography Contrast Induced Nephropathy (CIN among adult inpatients

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    Luciano Passamani Diogo

    2014-12-01

    Full Text Available Introduction: Contrast induced nephropathy (CIN is one of the complications of the use of intravascular contrast agents, being defined as a reduction of the glomerular filtration rate caused by the iodinated contrast. Most CIN data derive from the cardiovascular literature, which identified as the most consistent risk factors pre-existing chronic renal insufficiency and diabetes mellitus. However, these studies limit their conclusions to a more specific patient population. Computerized tomography as a cause of CIN has been studied less often. Objective: To report on the incidence of computerized tomography contrast induced nephropathy (CIN in an inpatient population of a tertiary general hospital, identifying potentially avoidable risk factors. Methods: We performed a prospective cohort study with inpatients admitted at a tertiary hospital requiring contrast-induced CT. The primary outcome was the development of CIN, measure by the alteration of serum creatinine or glomerular filtration rate in 48 or 72 hours. Through clinical interview, we verified possible risk factors and preventive measures instituted by the medical team and their association with development of CIN. Results: Of a total of 410 patients, 35 (8.5% developed CIN. There was a positive correlation between CIN and the presence of diabetes mellitus (OR = 2.15; 95%CI 1.35-4.06; p = 0.02, heart failure (OR = 2.23; 95%CI 1.18-8.8; p = 0.022, and renal failure (OR = 3.36; 95%CI 1.57- 7.17; p = 0.002 Conclusion: Incidence of CIN varies according to the population. Diabetes mellitus, heart failure and renal failure were independent risk factors for the development of CT-associated CIN. Further studies are needed to better understand and treat CT-associated CIN.

  5. Digital balanced detection for fast optical computerized tomography

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    Hafiz, Rehan; Ozanyan, Krikor B.

    2006-10-01

    Analogue Balanced Photo-detection has found extensive usage in high- sensitivity small signal applications e.g. coherent heterodyne detection. It is particularly effective for laser intensity noise removal. Nevertheless, the high cost of the commercially available analogue systems makes them unsuitable for multi-channel applications, such as fast tomography. In this paper a flexible, scalable, inexpensive and compact solution for multi channel digital balanced detection is presented. The proposed system has two components: an analogue front-end, comprising a differential photodiode amplifier for minimizing the external interference noise, and a digital balanced noise remover. The latter component initially calculates a balancing factor (BF) from the average power ratio of the signal and reference photocurrents, measured with the object removed from the signal path. Three digital balancing algorithms (DBAx) are considered for subsequent processing. In DBA1, BF is directly used in real-time ratiometric calculations. In DBA2, the BF is adjusted in real time by monitoring the window-averaged power of the received photocurrents. In DBA3, first the baseline is removed using differentiation and then ratiometric detection is performed. Using the digital alternative only one measurement of the reference beam is necessary for single-source, multi-channel detection systems. The data from multiple channels are processed in parallel by pipelined hardware, configured as a state machine. The proposed system leads to a fast optical computerized tomography system using digital balanced detection.

  6. Analysis of concrete material through gamma ray computerized tomography

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    Oliveira Junior, J.M. de [Universidade de Sorocaba - UNISO, SP (Brazil). Centro de Ciencias Exatas e Tecnologicas; Martins, A.C.G.; Milito, J.A. de [Faculdade de Engenharia de Sorocaba - FACENS, SP (Brazil)

    2004-09-15

    Computerized Tomography (CT) refers to the cross sectional imaging of an object from both transmission or reflection data collected by illuminating the object from many different directions. The most important contribution of CT is to greatly improve abilities to distinguish regions with different gamma ray transmittance and to separate over-lying structures. The mathematical problem of the CT imaging is that of estimating an image from its projections. These projections can represent, for example, the linear attenuation coefficient of {gamma}-rays along the path of the ray. In this work we will present some new results obtained by using tomographic techniques to analyze column samples of concrete to check the distribution of various materials and structural problems. These concrete samples were made using different proportions of stone, sand and cement. Another set of samples with different proportions of sand and cement were also used to verify the outcome from the CT analysis and the differences between them. Those samples were prepared at the Material Laboratory of Faculdade de Engenharia de Sorocaba, following the same procedures used in real case of concrete tests. The projections used in this work was obtained by Mini Computerized Tomograph of Uniso (MTCU), located at the Experimental Nuclear Physics Laboratory at University of Sorocaba. This tomograph operates with a gamma ray source of {sup 241}Am (photons of 60 keV and 100 mCi of intensity) and a NaI(Tl) solid state detector. The system features translation and rotation scanning modes, a 100 mm effective field of view, and 1 mm spatial resolution. The image reconstruction problem is solved using Discrete Filtered Backprojection (FBP). (author)

  7. Percutaneous nephrolithotomy in pediatric patients: is computerized tomography a must?

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    Gedik, Abdullah; Tutus, Ali; Kayan, Devrim; Yılmaz, Yakup; Bircan, Kamuran

    2011-02-01

    The aim of this study was to retrospectively evaluate the results of pediatric percutaneous nephrolithotomy (PNL) cases, and discuss the results and necessity of non-contrast computerized tomography (CT) in these cases. In all, 48 pediatric patients who underwent PNL were retrospectively evaluated. Before PNL, either intravenous urography or CT was performed. In all patients, we evaluated the PNL time, scopy time with stone burden, and complications. During the PNL procedure, we switched to open surgery in two cases: in one because of renal pelvis perforation and in the other because of transcolonic access. In one patient who was scheduled to undergo PNL, we performed open surgery, primarily because we detected a retrorenal colon with CT. The stone burden in 45 patients who underwent PNL was 445 ± 225 mm(2), the PNL time was 51 ± 23 min, and the scopy time was 6.1 ± 2.7 min. We removed nephrostomy tubes 1-4 days after the procedure. In two patients, 24 h after removal of nephrostomy tubes, we inserted double J stents because of prolonged urine extravasation from the tract. In all, 34 of the 45 patients were stone-free, 5 patients had clinically insignificant stone fragments, and 6 patients had residual stones. PNL is a safe and effective method in the treatment of pediatric patients with kidney stones. Clinical experience is the most important factor in obtaining stone-free results. CT should be performed in all pediatric patients in order to prevent colon perforation.

  8. A combined reconstruction algorithm for computerized ionospheric tomography

    Science.gov (United States)

    Wen, D. B.; Ou, J. K.; Yuan, Y. B.

    Ionospheric electron density profiles inverted by tomographic reconstruction of GPS derived total electron content TEC measurements has the potential to become a tool to quantify ionospheric variability and investigate ionospheric dynamics The problem of reconstructing ionospheric electron density from GPS receiver to satellite TEC measurements are formulated as an ill-posed discrete linear inverse problem A combined reconstruction algorithm of computerized ionospheric tomography CIT is proposed in this paper In this algorithm Tikhonov regularization theory TRT is exploited to solve the ill-posed problem and its estimate from GPS observation data is input as the initial guess of simultaneous iterative reconstruction algorithm SIRT The combined algorithm offer a more reasonable method to choose initial guess of SIRT and the use of SIRT algorithm is to improve the quality of the final reconstructed imaging Numerical experiments from the actual GPS observation data are used to validate the reliability of the method the reconstructed results show that the new algorithm works reasonably and effectively with CIT the overall reconstruction error reduces significantly compared to the reconstruction error of SIRT only or TRT only

  9. Computerized tomography with total variation and with shearlets

    Science.gov (United States)

    Garduño, Edgar; Herman, Gabor T.

    2017-04-01

    To reduce the x-ray dose in computerized tomography (CT), many constrained optimization approaches have been proposed aiming at minimizing a regularizing function that measures a lack of consistency with some prior knowledge about the object that is being imaged, subject to a (predetermined) level of consistency with the detected attenuation of x-rays. One commonly investigated regularizing function is total variation (TV), while other publications advocate the use of some type of multiscale geometric transform in the definition of the regularizing function, a particular recent choice for this is the shearlet transform. Proponents of the shearlet transform in the regularizing function claim that the reconstructions so obtained are better than those produced using TV for texture preservation (but may be worse for noise reduction). In this paper we report results related to this claim. In our reported experiments using simulated CT data collection of the head, reconstructions whose shearlet transform has a small ℓ 1-norm are not more efficacious than reconstructions that have a small TV value. Our experiments for making such comparisons use the recently-developed superiorization methodology for both regularizing functions. Superiorization is an automated procedure for turning an iterative algorithm for producing images that satisfy a primary criterion (such as consistency with the observed measurements) into its superiorized version that will produce results that, according to the primary criterion are as good as those produced by the original algorithm, but in addition are superior to them according to a secondary (regularizing) criterion. The method presented for superiorization involving the ℓ 1-norm of the shearlet transform is novel and is quite general: It can be used for any regularizing function that is defined as the ℓ 1-norm of a transform specified by the application of a matrix. Because in the previous literature the split Bregman algorithm is used

  10. Computerized tomography-based anatomic description of the porcine liver.

    Science.gov (United States)

    Bekheit, Mohamed; Bucur, Petru O; Wartenberg, Mylene; Vibert, Eric

    2017-04-01

    The knowledge of the anatomic features is imperative for successful modeling of the different surgical situations. This study aims to describe the anatomic features of the porcine using computerized tomography (CT) scan. Thirty large, white, female pigs were included in this study. The CT image acquisition was performed in four-phase contrast study. Subsequently, analysis of the images was performed using syngo.via software (Siemens) to subtract mainly the hepatic artery and its branches. Analysis of the portal and hepatic veins division pattern was performed using the Myrian XP-Liver 1.14.1 software (Intrasense). The mean total liver volume was 915 ± 159 mL. The largest sector in the liver was the right medial one representing around 28 ± 5.7% of the total liver volume. Next in order is the right lateral sector constituting around 24 ± 5%. Its volume is very close to the volume of the left medial sector, which represents around 22 ± 4.7% of the total liver volume. The caudate lobe represents around 8 ± 2% of the total liver volume.The portal vein did not show distinct right and left divisions rather than consecutive branches that come off the main trunk. The hepatic artery frequently trifurcates into left trunk that gives off the right gastric artery and the artery to the left lateral sector, the middle hepatic artery that supplies both the right and the left medial sectors and the right hepatic artery trunk that divides to give anterior branch to the right lateral lobe, branch to the right medial lobe, and at least a branch to the caudate lobe. Frequently, there is a posterior branch that crosses behind the portal vein to the right lateral lobe. The suprahepatic veins join the inferior vena cava in three distinct openings. There are communications between the suprahepatic veins that drain the adjacent sectors. The vein from the right lateral and the right medial sectors drains into a common trunk. The vein from the left lateral and from the left

  11. Acute renal failure following contrast injection for head computerized tomography in two patients with diabetic nephropathy

    Energy Technology Data Exchange (ETDEWEB)

    Matsunaga, H.; Sando, H.; Nunokawa, T.; Murakami, T.; Miyakawa, Y. (Tokyo Univ. (Japan). Faculty of Medicine)

    1981-10-01

    Two cases of diabetes mellitus with renal and retinal involvement developed acute renal failure after undergoing head computerized tomography. The first case was a 62-year-old male who had been diagnosed as having diabetes 25 years before. He had diabetic retinopathy of Scott IIIb. Before head computerized tomography, the serum BUN was 37 mg/dl, and creatinine was 4.1 mg/dl. Oliguria began immediately after the scanning and confinued for 48 hr. The serum levels of BUN and creatinine rose to 106 and 7.7 mg/dl, respectively. Case 2 was a 49-year-old male who had been diagnosed as having diabetes 15 years before. He showed Scott IIb and IV retinopathy. The BUN and creatinine levels in the serum were 32 and 2.3 mg/dl, respectively. After receiving head computerized tomography, he developed oliguria and remained oliguric for 48 hr. During that period, the serum levels of BUN and creatinin were elevated to 112 and 7.5 mg/dl, respectively. Fortunately, both of these patients recovered from the oliguria without resorting to hemodialysis. The iodine contrast medium routinely used for contrast enhancement in the head computerized tomography was implicated in the acute renal failure of these patients. Only eleven cases have so far been reported in the literature who developed acute renal failure following computerized tomography. In view of the three or four times greater dosis of iodine contrast medium employed in computerized tomography compared to intravenous pyelography, the acute incidence of such complications might be much higher. Among the thirteen cases including the two reported here, as many as eight were diabetic. It is well recongnized that the incidence of acute renal failure after intravenous pyelography is particularly high in cases of diabetic nephropathy.

  12. Status of routine post-mortem computerized tomography in Odense, Denmark

    DEFF Research Database (Denmark)

    Leth, Peter Mygind

    2008-01-01

      In February 2006 a dual slice CT scanner was installed at the Institute of Forensic Medicine in Odense, Denmark. Since that time a CT-scanning has been performed on all bodies prior to autopsy. This article provides an overview of the experience gained.  We found that computerized tomography...... rarely is a substitute for autopsy, but may contribute with important new information in many cases such as identifications (including mass-disasters), battered child, gunshot wounds, traffic accidents and air embolism. Computerized tomography provides documentation in digital form - easily stored...

  13. Positron emission tomography / computerized tomography evaluation of primary Hodgkin's disease of liver.

    Science.gov (United States)

    Gota, V S; Purandare, N C; Gujral, S; Shah, S; Nair, R; Rangarajan, V

    2009-01-01

    Occurrence of primary Hodgkin's lymphoma (PHL) of the liver is extremely rare. We report on a case of a 60-year-old male who presented with liver mass and B-symptomatology. Hepatoma or hepatic metastasis from a gastrointestinal primary was initially suspected. Tumor markers like AFP, CEA, Total PSA, and CA-19.9 were within normal limits. Positron Emission Tomography / Computerized Tomography (PET/CT) revealed a large hepatic lesion and a nodal mass in the porta hepatis. A liver biopsy was consistent with Hodgkin's lymphoma. There was complete regression of the hepatic lesion and evidence of shrinkage of the nodal mass following four cycles of chemotherapy. 18F Fluro -de-oxy Glucose (FDG) PET / CT in this case helped in establishing a primary hepatic lymphoma by demonstrating the absence of pathologically hypermetabolic foci in any other nodes or organs. PET / CT scan is a useful adjunct to conventional imaging and histopathology, not only to establish the initial diagnosis, but also to monitor treatment response in PHL.

  14. Status of routine post-mortem computerized tomography in Odense, Denmark

    DEFF Research Database (Denmark)

    Leth, Peter Mygind

    2008-01-01

    rarely is a substitute for autopsy, but may contribute with important new information in many cases such as identifications (including mass-disasters), battered child, gunshot wounds, traffic accidents and air embolism. Computerized tomography provides documentation in digital form - easily stored...

  15. Relevance of computerized tomography in the preoperative evaluation of patients with vulvar cancer

    DEFF Research Database (Denmark)

    Andersen, Kjeld; Zobbe, Vibeke; Thranov, Ingrid Regitze;

    2015-01-01

    BACKGROUND: The purpose of the study was to determine whether inclusion of computerized tomography (CT) in the prospective evaluation of vulvar cancer changed the surgical treatment strategy in terms of detection of lymph node metastases, tumor spread and comorbidity, and additionally to examine...

  16. A new cone beam computerized tomography system for use in endodontic surgery.

    Science.gov (United States)

    Tsurumachi, T; Honda, K

    2007-03-01

    To present a newly developed cone beam computerized tomography system (3DX Micro-CT) and its application in endodontic surgery. Cone beam CT has attracted considerable attention as a new diagnostic imaging technique in dentistry. The assessment of fractured endodontic instruments and the planning of endodontic surgery present challenges that conventional radiography cannot meet successfully. In this report, the value of the 3DX cone beam computerized radiography system is illustrated by the case of a fractured endodontic instrument protruding into the maxillary sinus.

  17. Current Human Reliability Analysis Methods Applied to Computerized Procedures

    Energy Technology Data Exchange (ETDEWEB)

    Ronald L. Boring

    2012-06-01

    Computerized procedures (CPs) are an emerging technology within nuclear power plant control rooms. While CPs have been implemented internationally in advanced control rooms, to date no US nuclear power plant has implemented CPs in its main control room (Fink et al., 2009). Yet, CPs are a reality of new plant builds and are an area of considerable interest to existing plants, which see advantages in terms of enhanced ease of use and easier records management by omitting the need for updating hardcopy procedures. The overall intent of this paper is to provide a characterization of human reliability analysis (HRA) issues for computerized procedures. It is beyond the scope of this document to propose a new HRA approach or to recommend specific methods or refinements to those methods. Rather, this paper serves as a review of current HRA as it may be used for the analysis and review of computerized procedures.

  18. [Ultrasound study and computerized tomography in the diagnosis of choledocholithiasis].

    Science.gov (United States)

    Borodach, V A; Borodach, A V; Shkuratova, N I

    2000-01-01

    A comparative analysis of the results of using the ultrasonic investigation and computed tomography in differential diagnosis of jaundice was made in 205 patients. The reliability of USI in diagnosis of cholelithiasis was 54.3%, and that of standard CT was 55.9%. The authors have developed and used computed tomocholangiography (direct and indirect) in 187 patients with pronounced bilirubinemia. Indirect tomocholangiography was used in patients with bilirubinemia not more than 157 mkm/l. Contrasted main bile ducts were noted in 95% of the patients. When the content of bilirubin in blood plasma was higher than the figures shown, the authors used the direct contrast of the bile ducts in combination with computed tomography. When using more perfect X-ray devices (CT) with the greater resolving power for diagnosis in jaundice patients, it was possible to get the overwhelming information about the state of the bile ducts.

  19. Calcification of all four parathyroid glands in a hemodialysis patient with secondary hyperparathyroidism revealed by computerized tomography.

    Science.gov (United States)

    Peces, R; Rodríguez, M; González, F; Ablanedo, P

    2001-09-01

    This report describes the parathyroid scan, computerized tomography and histologic findings in a young female hemodialysis patient with severe secondary hyperparathyroidism. These findings included hyperplasia and calcification of all four parathyroid glands.

  20. Computerized tomography technique for reconstruction of obstructed temperature field in infrared thermography

    Science.gov (United States)

    Sham, F. C.; Huang, Y. H.; Liu, L.; Chen, Y. S.; Hung, Y. Y.; Lo, T. Y.

    2010-01-01

    equations yields unknown thermal distribution in the area which needs to be reconstructed. Based on the proposed computerized tomography reconstruction (CTR) technique, deviated temperature data due to missing temperature data hidden by obstacle can be reconstructed. With further development, this technique may have the potential to be applied in the reconstruction of any smooth physical fields like phase information in optical techniques.

  1. Dental implants in bilateral bifid canal and compromised interocclusal space using cone beam computerized tomography

    Science.gov (United States)

    Ahmed, Nizar; Arunachalam, Lalitha Tanjore; Jacob, Caroline Annette; Kumar, Suresh Anand

    2016-01-01

    Knowledge of various anatomic landmarks is pivotal for important success. Bifid canals pose a challenge and can lead to difficulties while performing implant surgery in the mandible. Bifid canals can be diagnosed with panoramic radiography and more accurately with cone beam computerized tomography (CBCT). This case report details the placement of the implant in a patient with bilateral bifid canal and compromised interocclusal space, which was successfully treated using CBCT. PMID:27433073

  2. Evaluation of Biomaterials Using Micro-Computerized Tomography

    Science.gov (United States)

    Torris, A. T. Arun; Columbus, K. C. Soumya; Saaj, U. S.; Nair, Manitha B.; Krishnan, Kalliyana V.

    2008-09-01

    Micro-computed tomography or Micro-CT is a high resolution, non-invasive, x-ray scanning technique that allows precise three-dimensional imaging and quantification of micro-architectural and structural parameters of objects. Tomographic reconstruction is based on a cone-beam convolution-back-projection algorithm. Micro-architectural and structural parameters such as porosity, surface area to volume ratio, interconnectivity, pore size, wall thickness, anisotropy and cross-section area of biomaterials and bio-specimens such as trabecular bone, polymer scaffold, bio-ceramics and dental restorative were evaluated through imaging and computer aided manipulation of the object scan data sets.

  3. Single-Photon Emission Computerized Tomography (SPECT in Neuropsychiatry: A Review

    Directory of Open Access Journals (Sweden)

    B. K. Puri

    1992-01-01

    Full Text Available Cranial single-photon emission computerized tomography (SPECT or SPET can now give regional cerebral blood flow images with a resolution approaching that of positron emission tomography (PET. In this paper, the use of high resolution SPECT neuroimaging in neuropsychiatric disorders, including Alzheimer's disease, multi-infarct dementia, Pick's disease, progressive supranuclear palsy, Korsakoff's psychosis, Creutzfeld-Jakob disease, Parkinson's disease, Huntington's disease, schizophrenia, mood disorders, obsessive–compulsive disorder, HIV infection and AIDS is reviewed. Finally, further potential research and clinical uses, based on ligand studies, are outlined.

  4. Computerized tomography of the vertebral column and the vertebral canal. Computertomographie der Wirbelsaeule und des Spinalkanals

    Energy Technology Data Exchange (ETDEWEB)

    Thurn, P.; Friedmann, G.

    1983-01-01

    Soon after the introduction of whole-body computerized tomography, it became apparent that this method is a valuable aid in many clinical problems as especially the paravertebral soft parts can be satisfactorily evaluated. The further technical improvement of the devices to permit sectoral and thin-layer scans, provided the possibility of scanning especially the intraspinal structures with an accuracy not so far known. Thus it became for the first time possible to demonstrate details of the spinal cord, the cauda and the surrounding spinal meninges directly, making for quite a substantial improvement of differential diagnosis and the restriction of myelography, which remains an invasive method despite the use of water-soluble contrast media. As the limitations and possibilities of the method have meanwhile been definitely established to some extent, the results in cases of intervertebral disk lesions, tumors, malformations, traumata and other diseases, which are based on the evaluation of some 3,000 examinations, were compiled in the hope of providing a manual to those concerned with computerized tomography of the vertebrate column and the vertebral canal, making them familiar with the normal anatomy and the interpretation of images of pathologic conditions, and pointing out the efficiency of computerized tomography in this particular sector of X-ray diagnostics.

  5. Current concepts and advances: computerized tomography in sports medicine.

    Science.gov (United States)

    Buckwalter, Kenneth A

    2009-03-01

    Computed tomography (CT) is a widely used imaging technique. With the introduction of multidetector row technology, CT has been further refined. Although the focus of this transformation has been body and cardiac imaging, orthopedic imaging has benefited greatly. Specifically, the improvements in CT have made it possible to obtain submillimeter-thick slices that enable the creation of high-resolution multiplanar reformations from a single scan. These images usually are indistinguishable from direct plane acquisitions and provide unparalleled detail. Additionally, the factors responsible for causing CT image artifacts when hardware is present are much better understood and the improvements in CT technique and technology can be exploited to provide better images of patients with orthopedic hardware. The detailed multiplanar visualization of joints facilitates CT arthrography that has undergone a renaissance. CT arthrography is useful in the very large athlete or patient, the claustrophobic, and for those patients who fail a conventional magnetic resonance examination or magnetic resonance arthrogram.

  6. A New Approach for Enhancing the Quality of Medical Computerized Tomography Images

    Directory of Open Access Journals (Sweden)

    Mutaz Al-Frejat

    2016-05-01

    Full Text Available Computerized tomography (CT images contribute immensely to medical research and diagnosis. However, due to degradative factors such as noise, low contrast, and blurring, CT images tend to be a degraded representation of the actual body or part under investigation. To reduce the risk of imprecise diagnosis associated with poor-quality CT images, this paper presents a new technique designed to enhance the quality of medical CT images. The main objective is to improve the appearance of CT images in order to obtain better visual interpretation and analysis, which is expected to ease the diagnosis process. The proposed technique involves applying a median filter to remove noise from the CT images and then using a Laplacian filter to enhance the edges and the contrast in the images. Also, as CT images suffer from low contrast, a Contrast Limited Adaptive Histogram Equalization transform is also applied to solve this problem. The main strength of this transform is its modest computational requirements, ease of application, and excellent results for most images. According to a subjective assessment by a group of radiologists, the proposed technique resulted in excellent enhancement, including that of the contrast and the edges of medical CT images. From a medical perspective, the proposed technique was able to clarify the arteries, tissues, and lung nodules in the CT images. In addition, blurred nodules in chest CT images were enhanced effectively. Therefore the proposed technique can help radiologists to better detect lung nodules and can also assist in diagnosing the presence of tumours and in the detection of abnormal growths.

  7. Evaluation of the absorbed dose in odontological computerized tomography; Avaliacao da dose absorvida em tomografia computadorizada odontologica

    Energy Technology Data Exchange (ETDEWEB)

    Legnani, Adriano; Schelin, Hugo R.; Rocha, Anna Silvia P.S. da, E-mail: schelin@utfpr.edu.b, E-mail: anna@utfpr.edu.b [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil); Khoury, Helen J., E-mail: khoury@ufpe.b [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil)

    2011-10-26

    This paper evaluated the absorbed dose at the surface entry known as 'cone beam computed tomography' (CBCT) in odontological computerized tomography. Examination were simulated with CBCT for measurements of dose. A phantom were filled with water, becoming scatter object of radiation. Thermoluminescent dosemeters were positioned on points correspondent to eyes and salivary glands

  8. Clinical Relevance of Incidental Prostatic Lesions on FDG-Positron Emission Tomography/Computerized Tomography-Should Patients Receive Further Evaluation?

    NARCIS (Netherlands)

    Reesink, Daan J; Fransen van de Putte, Elisabeth E; Vegt, Erik; De Jong, Jeroen; van Werkhoven, Erik; Mertens, Laura S; Bex, Axel; van der Poel, Henk G; van Rhijn, Bas W G; Horenblas, Simon; Meijer, Richard P

    2016-01-01

    PURPOSE: FDG ((18)F-fluoro-2-deoxy-D-glucose)-PET/CT (positron emission tomography)/(computerized tomography) is a widely used diagnostic tool for whole body imaging. Incidental prostatic uptake is often found on FDG-PET/CT. The objective of this study was to determine the clinical relevance of inci

  9. Positron emission tomography/computerized tomography in the evaluation of primary non-Hodgkin's lymphoma of prostate.

    Science.gov (United States)

    Pan, Bo; Han, Jian-Kui; Wang, Shi-Cun; Xu, Ao

    2013-10-21

    Primary malignant lymphoma of the prostate is exceedingly rare. Here we report a case of a 65-year-old man who presented with increased urinary frequency, urinary urgency, and urinary incontinence for two years. Benign prostatic hypertrophy was suspected at primary impression. Ultrasound revealed a hypoechoic lesion of the prostate. The total serum prostate-specific antigen was within normal range. Positron emission tomography/computerized tomography (PET/CT) showed a hypermetabolic prostatic lesion. Prostate biopsy was consistent with a non-germinal center diffuse large B cell lymphoma. There was complete remission of the prostatic lesion following six cycles of chemotherapy as shown on the second PET/CT imaging. ¹⁸F-fluoro-deoxy glucose PET/CT is not only a complement to conventional imaging, but also plays a significant role in the diagnosis and evaluation of treatment response of prostatic lymphoma.

  10. Multiple-energy Techniques in Industrial Computerized Tomography

    Science.gov (United States)

    Schneberk, D.; Martz, H.; Azevedo, S.

    1990-08-01

    Considerable effort is being applied to develop multiple-energy industrial CT techniques for materials characterization. Multiple-energy CT can provide reliable estimates of effective Z (Z{sub eff}), weight fraction, and rigorous calculations of absolute density, all at the spatial resolution of the scanner. Currently, a wide variety of techniques exist for CT scanners, but each has certain problems and limitations. Ultimately, the best multi-energy CT technique would combine the qualities of accuracy, reliability, and wide range of application, and would require the smallest number of additional measurements. We have developed techniques for calculating material properties of industrial objects that differ somewhat from currently used methods. In this paper, we present our methods for calculating Z{sub eff}, weight fraction, and density. We begin with the simplest case -- methods for multiple-energy CT using isotopic sources -- and proceed to multiple-energy work with x-ray machine sources. The methods discussed here are illustrated on CT scans of PBX-9502 high explosives, a lexan-aluminum phantom, and a cylinder of glass beads used in a preliminary study to determine if CT can resolve three phases: air, water, and a high-Z oil. In the CT project at LLNL, we have constructed several CT scanners of varying scanning geometries using {gamma}- and x-ray sources. In our research, we employed two of these scanners: pencil-beam CAT for CT data using isotopic sources and video-CAT equipped with an IRT micro-focal x-ray machine source.

  11. New applications to computerized tomography: analysis of solid dosage forms produced by pharmaceutical industry

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira Junior, Jose Martins de [Universidade de Sorocaba (Uniso), SP (Brazil); Martins, Antonio Cesar Germano [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sorocaba, SP (Brazil)

    2009-07-01

    Full text: In recent years, computerized tomography (CT) has been used as a new probe to study solid dosage forms (tablets) produced by pharmaceutical industry. This new approach to study tablet and powder, or granulation, properties used in pharmaceutical industry is very suitable. First because CT can generate information that traditional technologies used in this kind of analysis can not, such as, density distribution of internal structures and tablet dimensions, pore size distribution, particle shape information, and also investigation of official and unofficial (counterfeit) copies of solid dosage forms. Second because CT is a nondestructive technique, allowing the use of tablets or granules in others analysis. In this work we discus how CT can be used to acquire and reconstruct internal microstructure of tablets and granules. CT is a technique that is based on attenuation of X-rays passing through matter. Attenuation depends on the density and atomic number of the material that is scanned. In this work, a micro-CT X-ray scanner (manufactured by the group of Applied Nuclear Physics at University of Sorocaba) was used to obtain three-dimensional images of the tablets and granules for nondestructive analysis. These images showed a non uniform density distribution of material inside some tablets, the morphology of some granules analyzed, the integrity of the liquid-filled soft-gelatin capsule and so on. It could also be observed that the distribution of different constituents presents an osmotic controlled-release dosage form. The present work shows that it is possible to use X-ray microtomography to obtain useful qualitative and quantitative information on the structure of pharmaceutical dosage forms. (author)

  12. Numerical calculation of the rock permittivity using micro computerized tomography image

    Science.gov (United States)

    Guo, Chen; Liu, Richard; Jin, Zhao; He, Zhili

    2014-05-01

    A numerical evaluation of the permittivity of sandstones through the micro computerized tomography (micro CT) images at 1.1 GHz is conducted by using an image porosity extracting algorithm and an improved Finite Difference Method (FDM). Within the acquired physical properties by 3D micro CT scanning, numerical method is used to compute the permittivity of the rock samples. A resonant cavity is used for experimental measurement. The simulated results of 2 clastic sandstone samples with dry state and saturated state are compared with experimental data for validating the accuracy of the proposed numerical method. The results show great agreement and the error of permittivity evaluation is less than 3%.

  13. Study on beam geometry and image reconstruction algorithm in fast neutron computerized tomography at NECTAR facility

    Energy Technology Data Exchange (ETDEWEB)

    Guo, J. [State Key Laboratory of Nuclear Physics and Technology and School of Physics, Peking University, 5 Yiheyuan Lu, Beijing 100871 (China); Lehrstuhl fuer Radiochemie, Technische Universitaet Muenchen, Garching 80748 (Germany); Buecherl, T. [Lehrstuhl fuer Radiochemie, Technische Universitaet Muenchen, Garching 80748 (Germany); Zou, Y., E-mail: zouyubin@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology and School of Physics, Peking University, 5 Yiheyuan Lu, Beijing 100871 (China); Guo, Z. [State Key Laboratory of Nuclear Physics and Technology and School of Physics, Peking University, 5 Yiheyuan Lu, Beijing 100871 (China)

    2011-09-21

    Investigations on the fast neutron beam geometry for the NECTAR facility are presented. The results of MCNP simulations and experimental measurements of the beam distributions at NECTAR are compared. Boltzmann functions are used to describe the beam profile in the detection plane assuming the area source to be set up of large number of single neutron point sources. An iterative algebraic reconstruction algorithm is developed, realized and verified by both simulated and measured projection data. The feasibility for improved reconstruction in fast neutron computerized tomography at the NECTAR facility is demonstrated.

  14. Method of evaluation of diagnostics reference levels in computerized tomography; Metodo de avaliacao de niveis de referencia de radiodiagnostico em tomografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Vega, Walter Flores

    1999-04-01

    Computerized tomography is a complex technique with several selectable exposition parameters delivering high doses to the patient. In this work it was developed a simple methodology to evaluate diagnostic reference levels in computerized tomography, using the concept of Multiple Scan Average Dose (MSAD), recently adopted by the Health Ministry. For evaluation of the MSAD, a dose distribution was obtained through a measured dose profile on the axial axis of a water phantom with thermoluminescence dosemeters, TLD-100, for different exam technique. The MSAD was evaluated hrough two distinct methods. First, it was evaluated by the integration of the dose profile of a single slice and, second, obtained by the integration on central slice of the profile of several slices. The latter is in of accordance with the ionization chamber method, suggesting to be the most practical method of dose evaluation to be applied in the diagnostic reference level assessment routine for CT, using TLDs. (author)

  15. Non-Conventional Applications of Computerized Tomography: Analysis of Solid Dosage Forms Produced by Pharmaceutical Industry

    Science.gov (United States)

    de Oliveira, José Martins; Germano Martins, Antonio César

    2010-05-01

    X-ray computed tomography (CT) refers to the cross-sectional imaging of an object measuring the transmitted radiation at different directions. In this work, we describe a non-conventional application of computerized tomography: visualization and improvements in the understanding of some internal structural features of solid dosage forms. A micro-CT X-ray scanner, with a minimum resolution of 30 μm was used to characterize some pharmaceutical tablets, granules, controlled-release osmotic tablet and liquid-filled soft-gelatin capsules. The analysis presented in this work are essentially qualitative, but quantitative parameters, such as porosity, density distribution, tablets dimensions, etc. could also be obtained using the related CT techniques.

  16. Prediction of traumatic avascular necrosis of the femoral head by single photon emission computerized tomography and computerized tomography: an experimental study in dogs

    Institute of Scientific and Technical Information of China (English)

    SHEN Feng; YAN Zuo-qin; GUO Chang-an; SHI Hong-cheng; GU Yu-shen; ZENG Meng-su; LU Xiao-yu; LIU Jun

    2011-01-01

    Objective: To evaluate the femoral head perfusion and to predict the traumatic avascular necrosis (AVN) of the femoral head by single photon emission computerized tomography and computerized tomography (SPECT/CT). Methods: Totally 18 adult beagle dogs were divided randomly into three equal-sized (n=6) groups. Subsequently different degrees of ischemia model were developed by destroying blood vessels of the femoral head. The left hip received sham operation as normal control and the right hip underwent blood interruption. In Group A, the ligamentum teres was cut off. In Group B, the marrow cavity of the right femoral neck was destroyed while in Group C, the soft tissues at the base of the femoral neck were stripped in addition to the resection of the ligamentum teres and destruction of the marrow cavity. Three hours after surgery, SPECT/ CT was performed. Laser Doppler Flowmetry (LDF) measurements were also obtained at three different time points (before operation, immediately and three hours after operation) in order to assess the change process of blood supply to the femoral head. Results: SPECT/CT showed no significant difference in the radionuclide uptake between the right and left femoral heads in Group A (t=-0.09, P=0.94) and Group B (t= 0.52, P=0.62). However, in Group C, it was 261 ±62 for the right femoral head, only 12% of that in the left femoral head. LDF measurements indicated that the femoral head perfusion was decreased from (45.0±3.3) PU to (39.1±3.7) PU in Group A, from (44.0±2.7) PU to (34.3±2.6) PU in Group B, and from (47.3 ±2.1) PU to (4.96±0.6) PU in Group C immediately after operation. However, the perfusion was restored and returned to normal values three hours after operation except in Group C. Conclusion: SPECT/CT could assess the perfusion of the femoral head semiquantitatively, which might be useful in predicting the development of traumatic AVN.

  17. Density evaluation by computerized tomography in plain soils over different manipulation systems; Avaliacao da densidade pelo metodo da tomografia computadorizada de um planossolo sob diferentes sistemas de manejo

    Energy Technology Data Exchange (ETDEWEB)

    Pedrotti, Alceu [Lavras Univ., MG (Brazil). Dept. de Ciencia do Solo; Pauletto, Eloy Antonio [Pelotas Univ., RS (Brazil). Dept. de Solos; Crestana, Silvio [Empresa Brasileira de Pesquisa Agropecuaria (EMBRAPA), Sao Carlos, SP (Brazil). Centro Nacional de Pesquisa e Desenvolvimento de Instrumentacao Agropecuaria (CNPDIA)

    1996-08-01

    The objective of this paper is the evaluation of a plain soil density in different culture systems determined by X ray computerized tomography.It was observed a larger variation in densities in soils profiles analysed. The identification of layers is better utilising computerized tomography than others technic 1 fig.

  18. Prediction of Deep Neck Abscesses by Contrast-Enhanced Computerized Tomography in 76 Clinically Suspect Consecutive Patients

    NARCIS (Netherlands)

    Freling, Nicole; Roele, Elise; Schaefer-Prokop, Cornelia; Fokkens, Wytske

    2009-01-01

    Objectives/Hypothesis: Contrast-enhanced computerized tomography (CECT) has become the imaging method of choice in patients with clinical suspicion of a deep neck abscess. The purpose of this retrospective study was to assess the predictive value of the diagnosis of deep neck abscess using CECT. Stu

  19. Cone-beam computerized tomography (CBCT) imaging of the oral and maxillofacial region: a systematic review of the literature.

    NARCIS (Netherlands)

    Vos, W. De; Casselman, J.W.; Swennen, G.R.

    2009-01-01

    This study reviewed the literature on cone-beam computerized tomography (CBCT) imaging of the oral and maxillofacial (OMF) region. A PUBMED search (National Library of Medicine, NCBI; revised 1 December 2007) from 1998 to December 2007 was conducted. This search revealed 375 papers, which were scree

  20. Accuracy of computerized tomography in the diagnosis of colovesical fistula secondary to diverticular disease.

    Science.gov (United States)

    Jarrett, T W; Vaughan, E D

    1995-01-01

    We reviewed 9 consecutive patients with colovesical fistula secondary to diverticulitis during a 2-year period. Preoperative evaluation included computerized tomography (CT) and a barium enema or colonoscopy in all patients (8 underwent cystoscopy). All patients subsequently underwent laparotomy with a single or multiple staged repair. Using CT criteria for diagnosis of colovesical fistulas, the study accurately predicted the presence and location of fistula in 8 patients, and was suspicious in 1. Findings at cystoscopy only diagnosed 3 fistulas and were suspicious in 4. The remaining diagnostic tests, including excretory urography, barium enema, abdominal plain films, colonoscopy and cystogram, were unremarkable except for a single cystogram and barium enema. In addition to documenting the fistula, CT provided important intraluminal and extraluminal pathological findings helpful in planning subsequent surgery. Thus, CT should be included in the initial evaluation of patients with suspected colovesical fistula.

  1. Dose evaluation in diagnostic for computerized tomography; Evaluacion de dosis en diagnostico por tomografia computarizada

    Energy Technology Data Exchange (ETDEWEB)

    Flores, W.; Borges, J.C.; Mota, H. [Universidad Federal de Rio de Janeiro, PEN/COPPE/UFRJ. Caixa Postal 68509. 21945-970 Rio de Janeiro (Brazil)

    1998-12-31

    The patients which are subjected to computerized tomography tests are exposed to relatively high doses given as result doses on organs that are not matter to test. It was realized a dose levels raising in patients subjected to tests by T C, utilizing to measure this magnitude, TLD-100 thermoluminescent dosemeters which were put directly on the patient, in eye regions, thyroid, breast and navel; founding doses fluctuating between 29.10-49.39 mGy in organs examined and dose values between 0.21-29.10 mGy for organs that no matter to test. The applications of ionizing radiations in medicine do not have dose limits, but paying attention to the radiological protection optimization principle, it is recommended the use of clothes to anti-rays protection for zones not examined, getting with this to reduce the level doses as low as possible, without this to diminish the test quality. (Author)

  2. Computerized Tomography Technique for the Investigation of the Maxillary First Molar Mesiobuccal Root

    Directory of Open Access Journals (Sweden)

    Stefano Corbella

    2013-01-01

    Full Text Available The aim of this paper was to review the literature about the use of computerized tomography to evaluate the presence and characteristics of the second mesiobuccal canal in the maxillary first molar. An electronic search was performed. Frequencies of the presence of second mesiobuccal canal and root anatomy characteristics were extracted from the selected studies. Pooled frequencies were calculated as weighted means. Seven articles were included. A second mesiobuccal canal was present in 59.32% of the teeth, and it was noncommunicating in 58.45% of teeth presenting the canal itself. The most common root canal morphology was single canal or two separated canals. The present paper showed that cone beam CT is a viable radiologic device for the evaluation of the mesiobuccal root of maxillary first molars. In fact, it was observed that the frequency of second mesiobuccal canal detection is similar to those presented by clinical studies or micro-CT evaluations.

  3. Single photon emission computerized tomography (SPECT) in detecting neurodegeneration in Huntington's disease.

    Science.gov (United States)

    Reynolds, N C; Hellman, R S; Tikofsky, R S; Prost, R W; Mark, L P; Elejalde, B R; Lebel, R; Hamsher, K S; Swanson, S; Benezra, E E

    2002-01-01

    Single photon emission computerized tomography (SPECT) studies were performed on 34 manifest Huntington's disease (HD) patients at various stages of clinical pathology ranging from early chorea to late dystonia with or without signs of dementia and 12 pre-symptomatic patients with abnormal terminal CAG expansions. Thirty HD patients with obvious clinical signs and seven pre-symptomatic patients without signs or symptoms of HD displayed selective caudate hypoperfusion by direct visual inspection. Such qualitative, selective striatal hypoperfusion patterns can be indicative of early and persistent metabolic changes in striatal neuropathology. SPECT studies can be useful in documenting early pre-clinical changes in patients with abnormal terminal CAG expansions and in confirming the presence of caudate pathology in patients with clinical signs of HD.

  4. Weight-based contrast administration in the computerized tomography evaluation of acute pulmonary embolism

    Science.gov (United States)

    Laurent, Lisa; Zamfirova, Ina; Sulo, Suela; Baral, Pesach

    2017-01-01

    Abstract Compare individualized contrast protocol, or weight-based protocol, to standard methodology in evaluating acute pulmonary embolism. Retrospective chart review was performed on patients undergoing computed tomography angiography with standard contrast protocol (n = 50) or individualized protocol (n = 50). Computerized tomography images were assessed for vascular enhancement and image quality. Demographics were comparable, however, more patients in the individualized group were admitted to intensive care unit (48% vs 16%, P = 0.004). Vascular enhancement and image quality were also comparable, although individualized protocol had significantly fewer contrast and motion artifact limitations (28% vs 48%, P = 0.039). Fifteen percent decrease in intravenous contrast volume was identified in individualized group with no compromise in image quality. Individualized contrast protocol provided comparable vascular enhancement and image quality to the standard, yet with fewer limitations and lower intravenous contrast volume. Catheter-gauge flow rate restrictions resulting in inconsistent technologist exam execution were identified, supporting the need for further investigation of this regimen. PMID:28151887

  5. Compact cold stage for micro-computerized tomography imaging of chilled or frozen samples

    Science.gov (United States)

    Hullar, Ted; Paige, David F.; Rowland, Douglas J.; Anastasio, Cort

    2014-04-01

    High resolution X-ray microCT (computerized tomography) can be used to image a variety of objects, including temperature-sensitive materials. In cases where the sample must be chilled or frozen to maintain sample integrity, either the microCT machine itself must be placed in a refrigerated chamber, or a relatively expensive commercial cold stage must be purchased. We describe here the design and construction of a low-cost custom cold stage suitable for use in a microCT imaging system. Our device uses a boron nitride sample holder, two-stage Peltier cooler, fan-cooled heat sink, and electronic controller to maintain sample temperatures as low as -25 °C ± 0.2 °C for the duration of a tomography acquisition. The design does not require modification to the microCT machine, and is easily installed and removed. Our custom cold stage represents a cost-effective solution for refrigerating CT samples for imaging, and is especially useful for shared equipment or machines unsuitable for cold room use.

  6. Muons tomography applied to geosciences and volcanology

    Energy Technology Data Exchange (ETDEWEB)

    Marteau, J., E-mail: marteau@ipnl.in2p3.fr [Institut de Physique Nucleaire de Lyon (UMR CNRS-IN2P3 5822), Universite Lyon 1, Lyon (France); Gibert, D.; Lesparre, N. [Institut de Physique du Globe de Paris (UMR CNRS 7154), Sorbonne Paris Cite, Paris (France); Nicollin, F. [Geosciences Rennes (CNRS UMR 6118), Universite Rennes 1, Bat. 15 Campus de Beaulieu, 35042 Rennes cedex (France); Noli, P. [Universita degli studi di Napoli Federico II and INFN sez. Napoli (Italy); Giacoppo, F. [Laboratory for High Energy Physics, University of Bern, SidlerStrasse 5, CH-3012 Bern (Switzerland)

    2012-12-11

    Imaging the inner part of large geological targets is an important issue in geosciences with various applications. Different approaches already exist (e.g. gravimetry, electrical tomography) that give access to a wide range of information but with identified limitations or drawbacks (e.g. intrinsic ambiguity of the inverse problem, time consuming deployment of sensors over large distances). Here we present an alternative and complementary tomography method based on the measurement of the cosmic muons flux attenuation through the geological structures. We detail the basics of this muon tomography with a special emphasis on the photo-active detectors.

  7. Muons tomography applied to geosciences and volcanology

    CERN Document Server

    Marteau, J; Lesparre, N; Nicollin, F; Noli, P; Giacoppo, F

    2012-01-01

    Imaging the inner part of large geological targets is an important issue in geosciences with various applications. Dif- ferent approaches already exist (e.g. gravimetry, electrical tomography) that give access to a wide range of informations but with identified limitations or drawbacks (e.g. intrinsic ambiguity of the inverse problem, time consuming deployment of sensors over large distances). Here we present an alternative and complementary tomography method based on the measurement of the cosmic muons flux attenuation through the geological structures. We detail the basics of this muon tomography with a special emphasis on the photo-active detectors.

  8. Cone-beam computerized tomography (CBCT) imaging of the oral and maxillofacial region: a systematic review of the literature.

    Science.gov (United States)

    De Vos, W; Casselman, J; Swennen, G R J

    2009-06-01

    This study reviewed the literature on cone-beam computerized tomography (CBCT) imaging of the oral and maxillofacial (OMF) region. A PUBMED search (National Library of Medicine, NCBI; revised 1 December 2007) from 1998 to December 2007 was conducted. This search revealed 375 papers, which were screened in detail. 176 papers were clinically relevant and were analyzed in detail. CBCT is used in OMF surgery and orthodontics for numerous clinical applications, particularly for its low cost, easy accessibility and low radiation compared with multi-slice computerized tomography. The results of this systematic review show that there is a lack of evidence-based data on the radiation dose for CBCT imaging. Terminology and technical device properties and settings were not consistent in the literature. An attempt was made to provide a minimal set of CBCT device-related parameters for dedicated OMF scanners as a guideline for future studies.

  9. Normal Positron Emission Tomography-Computerized Tomogram in a Patient with Apparent Mesenteric Panniculitis: Biopsy Is Still the Answer

    Directory of Open Access Journals (Sweden)

    Eli D. Ehrenpreis

    2009-04-01

    Full Text Available Mesenteric panniculitis (also known as sclerosing mesenteritis is a chronic inflammatory disease of the mesenteric connective tissue. It is known to have a wide spectrum of clinical and radiological presentations. In general, biopsy is recommended for diagnosis; however, a recent study proposed that a negative positron emission tomography- computerized tomography (PET-CT scan is accurate in differentiating benign and neoplastic mesenteric processes [Br J Radiol 2006;79:37–43]. The following case report questions the accuracy of PET-CT in this setting and confirms the requirement for biopsy to rule out the presence of mesenteric lymphoma.

  10. Pore structure of ore granular media by computerized tomography image processing

    Institute of Scientific and Technical Information of China (English)

    WU Ai-xiang; YANG Bao-hua; XI Yong; JIANG Huai-chun

    2007-01-01

    The pore structure images of ore particles located at different heights of leaching column were scanned with X-ray computerized tomography (CT) scanner, the porosity and pore size distribution were calculated and the geometrical shape and connectivity of pores were analyzed based on image process method, and the three dimensional reconstruction of pore structure images was realized. The results show that the porosity of ore particles bed in leaching column is 42.92%, 41.72%, 39.34% at top,middle and bottom zone, respectively. Obviously it has spatial variability and decreases appreciably along the height of the column.The overall average porosity obtained by image processing is 41.33% while the porosity gotten from general measurement method in laboratory is 42.77% showing the results of both methods are consistent well. The pore structure of ore granular media is characterized as a dynamical space network composed of interconnected pore bodies and pore throats. The ratio of throats with equivalent diameter less than 1.91 mm to the total pores is 29.31%, and that of the large pores with equivalent diameter more than 5.73 mm is 2.90%.

  11. A review of computerized tomography in blunt abdominal trauma at Christchurch Hospital

    Energy Technology Data Exchange (ETDEWEB)

    Bohmer, R.D.; Cowan, I [Christchurch Hospital (New Zealand)

    1997-02-01

    A review was undertaken of computerized tomography (CT) of the abdomen, performed between March 1993 and December 1994 for blunt abdominal trauma at Christchurch Hospital. CT findings were correlated with the clinical outcome. The outcome was either recovery from an abdominal point of view with or without laparotomy, or post mortem. A total of 116 CTs were reviewed, of which 76 were normal. CT was highly sensitive and specific for a variety of abdominal traumatic lesions. there were 1 false positive and 4 false negatives (only 2 of these significant). There was 1 non-therapeutic laparotomy based on CT findings. There was only 1 case of delayed treatment based on CT results. Three patients had unexplained findings of pneumoperitoneum. Care should be taken when interpreting the presence of free intraperitoneal air on CT scan. The possibility of missed bowel perforation should be considered, especially in the presence of free intra-abdominal fluid and no solid organ injury to account for it. CT scans are useful in the conservative management of solid organ injuries. 15 refs., 1 tab., 1 fig.

  12. The approximate inversion as a reconstruction method in X-ray computerized tomography

    CERN Document Server

    Dietz, R L

    1999-01-01

    The mathematical model of the X-ray computerized tomography will be developed in the first chapter, the approximate inversion will be introduced, and the Radon Transform will be used as an example to demonstrate calculation of a reconstruction cone. In the second chapter, a reconstruction method for the parallel geometry is discussed, leading to derivation of the method for a fan-beam geometry. The approximate inversion calculated for the limited-angle case is presented as an example of incomplete data problems. As with complete data problems, numerical examples are given and the method is compared with existing other methods. 3D reconstruction is the topic of the third chapter. Although of no relevance in practice, a parallel geometry will be examined. No problems are encountered in transferring the reconstruction cone to the cone beam geometry, but only for a scanning curve which also is of no relevance in practice. A further reconstruction method is presented for curves fulfilling the so-called Tuy conditi...

  13. Comparison between multislice and cone-beam computerized tomography in the volumetric assessment of cleft palate.

    Science.gov (United States)

    Albuquerque, Marco Antonio; Gaia, Bruno Felipe; Cavalcanti, Marcelo Gusmão Paraíso

    2011-08-01

    The aim of this study was to determine the applicability of multislice and cone-beam computerized tomography (CT) in the assessment of bone defects in patients with oral clefts. Bone defects were produced in 9 dry skulls to mimic oral clefts. All defects were modeled with wax. The skulls were submitted to multislice and cone-beam CT. Subsequently, physical measurements were obtained by the Archimedes principle of water displacement of wax models. The results demonstrated that multislice and cone-beam CT showed a high efficiency rate and were considered to be effective for volumetric assessment of bone defects. It was also observed that both CT modalities showed excellent results with high reliability in the study of the volume of bone defects, with no difference in performance between them. The clinical applicability of our research has shown these CT modalities to be immediate and direct, and they is important for the diagnosis and therapeutic process of patients with oral cleft. Copyright © 2011 Mosby, Inc. All rights reserved.

  14. Correlations between computerized tomography of the head and motor developmental disturbances of children with cerebral palsy

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y.H. (Nagasaki Univ. (Japan). School of Medicine)

    1981-01-01

    Two hundred and eighty-two children with cerebral palsy (C.P.) and thirty-seven normal children were studied by computerized tomography (C.T.) of the head for finding out the correlations between the organic damage of the brain and the motor developmental disturbance. The abnormal findings of C.T. were: enlargement of the ventricular system, high density area, low density area and porencephalus, enlargement of the sulcus and anomaly of the medial structure. Enlargement of the ventricular system seemed to have correlation with spasticity; the portion and the extent of the enlargement corresponded to the affected extremities and the severity of the spasticity. Children of other types also showed various abnormal C.T. findings but, in general, less than that of spastic types. The prognosis of the motor development of C.P. children cannot be predicted by serial C.T. examinations strictly, because early treatment could cause improvement to that of these children. However, it is of worthy notice that C.T. is an effective method of helping to diagnose the motor developmental disturbance in earlier childhood.

  15. Computerized tomography evaluation of a resorbable implant after transforaminal lumbar interbody fusion.

    Science.gov (United States)

    Kuklo, Timothy R; Rosner, Michael K; Polly, David W

    2004-03-15

    Synthetic bioabsorbable implants have recently been introduced in spinal surgery; consequently, the indications, applications, and results are still evolving. The authors used absorbable interbody spacers (Medtronic Sofamor Danek, Memphis, TN) packed with recombinant bone morphogenetic protein (Infuse; Medtronic Sofamor Danek) for single- and multiple-level transforaminal lumbar interbody fusion (TLIF) procedures over a period of 18 months. This is a consecutive case series in which postoperative computerized tomography (CT) scanning was used to assess fusion status. There were 22 patients (17 men, five women; 39 fusion levels) whose mean age was 41.6 years (range 23-70 years) and in whom the mean follow-up duration was 12.4 months (range 6-18 months). Bridging bone was noted as early as the 3-month postoperative CT scan when obtained; solid arthrodesis was routinely noted between 6 and 12 months in 38 (97.4%) of 39 fusion levels. In patients who underwent repeated CT scanning, the fusion mass appeared to increase with time, whereas the disc space height remained stable. Although the results are early (mean 12-month follow-up duration), there was only one noted asymptomatic delayed union/nonunion at L5-S1 in a two-level TLIF with associated screw breakage. There were no infections or complications related to the cages. The bioabsorbable cages appear to be a viable alternative to metal interbody spacers, and may be ideally suited to spinal interbody applications because of their progressive load-bearing properties.

  16. Metal Artifact Reduction and Segmentation of Dental Computerized Tomography Images Using Least Square Support Vector Machine and Mean Shift Algorithm.

    Science.gov (United States)

    Mortaheb, Parinaz; Rezaeian, Mehdi

    2016-01-01

    Segmentation and three-dimensional (3D) visualization of teeth in dental computerized tomography (CT) images are of dentists' requirements for both abnormalities diagnosis and the treatments such as dental implant and orthodontic planning. On the other hand, dental CT image segmentation is a difficult process because of the specific characteristics of the tooth's structure. This paper presents a method for automatic segmentation of dental CT images. We present a multi-step method, which starts with a preprocessing phase to reduce the metal artifact using the least square support vector machine. Integral intensity profile is then applied to detect each tooth's region candidates. Finally, the mean shift algorithm is used to partition the region of each tooth, and all these segmented slices are then applied for 3D visualization of teeth. Examining the performance of our proposed approach, a set of reliable assessment metrics is utilized. We applied the segmentation method on 14 cone-beam CT datasets. Functionality analysis of the proposed method demonstrated precise segmentation results on different sample slices. Accuracy analysis of the proposed method indicates that we can increase the sensitivity, specificity, precision, and accuracy of the segmentation results by 83.24%, 98.35%, 72.77%, and 97.62% and decrease the error rate by 2.34%. The experimental results show that the proposed approach performs well on different types of CT images and has better performance than all existing approaches. Moreover, segmentation results can be more accurate by using the proposed algorithm of metal artifact reduction in the preprocessing phase.

  17. Evaluation method of reference levels of radiation diagnostic in computerized tomography; Metodo de evaluacion de niveles de referencia de radiodiagnostico en tomografia computarizada

    Energy Technology Data Exchange (ETDEWEB)

    Flores, Walter; Borges, Jose C. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Nuclear; Mota, Helvecio C. [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil). Dept. de Fisica Medica

    2000-07-01

    The computerized tomography (CT) is a complex technique, with many parameters to be selected and protocols of quality control not standardized, connected with high doses in the patients. In this work a simple methodology is developed, to evaluate levels of reference of diagnosis in computerized tomography using the concept of Multiple Scan Average Dose (MSAD), recently adopted by the Ministry of Health of Brazil. This methodology, can be used in the routine of inspection of evaluation of radiological safety in medical radiation diagnostics, executed by the Department of Medical Physics of the Institute of Radiation Protection and Dosimetry and by the sanitary authorities in Brazil. In order to evaluate this dosimeter magnitude the distribution of dose it was studied the dose distribution obtained trough a profile of dose measured in the axial axis of a simulator(phantom) of water with thermoluminescent dosimeters, TLD-100, for three techniques of examination by CT. The magnitude MSAD was evaluated by means of two different methods. In first, it was evaluated for an only cut, and in the second for multiple cuts. This last method presents/displays to be more practical and adapted to be applied in the routine of evaluation of reference levels, with TLDs.

  18. Muon tomography applied to active volcanoes

    CERN Document Server

    Marteau, Jacques; Gibert, Dominique; Ianigro, Jean-Christophe; Jourde, Kevin; Kergosien, Bruno; Rolland, Pascal

    2015-01-01

    Muon tomography is a generic imaging method using the differential absorption of cosmic muons by matter. The measured contrast in the muons flux reflects the matter density contrast as it does in conventional medical imaging. The applications to volcanology present may advantadges induced by the features of the target itself: limited access to dangerous zones, impossible use of standard boreholes information, harsh environmental conditions etc. The Diaphane project is one of the largest and leading collaboration in the field and the present article summarizes recent results collected on the Lesser Antilles, with a special emphasis on the Soufri\\`ere of Guadeloupe.

  19. Morphometric analysis of the cervical spine of Indian population by using computerized tomography

    Directory of Open Access Journals (Sweden)

    Partha Sarathi Banerjee

    2012-08-01

    Full Text Available The purpose of the present study was to measure the surgically important morphological parameters of cervical spine region of a representative sample of Indian population from the images obtained through computerized tomography (CT. Another purpose has been to compare the computed statistical mean, standard deviation and range of variation of these data with those of other Asian population and also European/American populations. With that aim, ninety five (95 CT scan data of Indian people (73 for male patients and 22 for female patients pertaining to undeformed normal cervical spine has been collected from an Indian hospital. From these, 15 important morphological parameters have been measured. These values have been tabulated and their mean, standard deviation and range of variation have been computed. It has been found that pedicle dimensions of Indian people are smaller at almost all vertebra levels as compared to Caucasian people. Pedicle axis length for Indian people are found to be smaller at C3, C4 and C5 levels than those for other Asian people including Chinese people, but it is bigger at C6 and C7 levels. Indian people have longer measurements of pedicle length + lateral mass on an average than their other Asian counterparts at C5, C6 and C7 levels, but shorter measurements at C3 and C4 levels. The results of the present work may help in better understanding of morphological parameters of cervical spine region of Indian population. It may be further useful in designing spinal implants which would be biomechanically compatible to the anatomy of Indian people.

  20. 改进模型的层析成像算法%IMPROVED MODEL FOR COMPUTERIZED TOMOGRAPHY

    Institute of Scientific and Technical Information of China (English)

    罗文歆; 朱自强; 赵晓博

    2012-01-01

    井间地震层析成像技术能够提供钻孔之间地质体的高分辨图像.LTI法与SIRT法相结合是目前使用较广的一种层析成像算法,在此基础上考虑到一个较好的初始模型能提高算法的准确性及效率性,以及在SIRT算法当中如何分配残差能使反演的结果更好,提出了改进模型的层析成像算法.此方法基于LTI法进行射线追踪得到每个接收点在初始模型上的理论走时后,就利用这个理论走时与实际拾取走时的差值以及射线追踪所得到的射线路径,对初始模型进行修正.通过数值模拟实验发现,该算法的效果较原始算法有一定的提高.%Expressway construction in karst developing area, which need exact information of karst. Cross-well seismic computerized tomography is a geophysical exploration method, which use seismic wave to explore the media between wells. It can provide high resolution image of the target. LTI and SIRT are widely used in computerized tomography, improved model method for computerized tomography which s based on that. It consider that a better initial model can improve the accuracy and efficiency of the algorithm, and the distribution of residual error in SIRT can also improve the result of inversion. In some degree, the method improve the result by the numerical modeling experiment.

  1. Calculating the number of shock waves, expulsion time, and optimum stone parameters based on noncontrast computerized tomography characteristics.

    Science.gov (United States)

    Foda, Khaled; Abdeldaeim, Hussein; Youssif, Mohamed; Assem, Akram

    2013-11-01

    To define the parameters that accompanied a successful extracorporeal shock wave lithotripsy (ESWL), namely the number of shock waves (SWs), expulsion time (ET), mean stone density (MSD), and the skin-to-stone distance (SSD). A total of 368 patients diagnosed with renal calculi using noncontrast computerized tomography had their MSD, diameter, and SSD recorded. All patients were treated using a Siemens lithotripter. ESWL success meant a stone-free status or presence of residual fragments 934 HUs and SSD >99 mm. The required number of SWs and the expected ET can be anticipated. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Central representation of phantom limb phenomenon in amputees studied with single photon emission computerized tomography.

    Science.gov (United States)

    Liaw, M Y; You, D L; Cheng, P T; Kao, P F; Wong, A M

    1998-01-01

    To explore the possible mechanisms of phantom limb discomfort after amputation, three amputees with phantom limb pain were studied. This study examined the change of regional cerebral blood flow using technetium-99m hexamethylpropyleneamine oxime-single photon emission computerized tomography, which was arranged at the time of severe phantom limb discomfort and after the discomfort subsided or was completely relieved. Nine representative transverse slices parallel to the orbitomeatal line were selected for quantification. The cortical ribbon (2-cm thickness) was equally subdivided into 12 symmetrical pairs of sector regions of interest in each slice. The irregularly shaped regions of interest were drawn manually around the right thalamus and basal ganglion and then mirrored to the left thalamus and basal ganglion. The contralateral to ipsilateral ratio of regional cerebral blood flow for each area was calculated. The intensity of phantom limb pain was evaluated on a 0 to 10 visual analog scale. In Cases 1 and 2, the contralateral to ipsilateral regional cerebral blood flow ratios of multiple areas of the frontal, temporal, or parietal lobes were increased at the time of more severe phantom limb pain, and the ratios were normalized or even decreased when the phantom limb pain subsided. In Case 3, increased contralateral to ipsilateral regional cerebral blood flow ratios were also found over the frontal, temporal, and parietal lobe. However, most of the increased regional cerebral blood flow ratios of regions of interest in the first study persisted in the follow-up study. Also, the regional cerebral blood flow ratios of greater number of regions of interest of the same gyrus and new gyrus were increased. There was no significant right-left difference of regional cerebral blood flow over bilateral thalami and basal ganglia in all three cases. The results suggested that phantom limb pain might be associated with cortical activation involving the frontal, temporal, or

  3. Prediction of differential creatinine clearance in chronically obstructed kidneys by non-contrast helical computerized tomography

    Directory of Open Access Journals (Sweden)

    Ng C.F.

    2004-01-01

    Full Text Available PURPOSE: We investigate the use of non-contrast helical computerized tomography (NCHCT in the measurement of differential renal parenchymal volume as a surrogate for differential creatinine clearance (CrCl for unilateral chronically obstructed kidney. MATERIALS AND METHODS: Patients with unilateral chronically obstructed kidneys with normal contralateral kidneys were enrolled. Ultrasonography (USG of the kidneys was first done with the cortical thickness of the site with the most renal substance in the upper pole, mid-kidney, and lower pole of both kidneys were measured, and the mean cortical thickness of each kidney was calculated. NCHCT was subsequently performed for each patient. The CT images were individually reviewed with the area of renal parenchyma measured for each kidney. Then the volume of the slices was summated to give the renal parenchymal volume of both the obstructed and normal kidneys. Finally, a percutaneous nephrostomy (PCN was inserted to the obstructed kidney, and CrCl of both the obstructed kidney (PCN urine and the normal side (voided urine were measured two 2 after the relief of obstruction. RESULTS: From March 1999 to February 2001, thirty patients were enrolled into the study. Ninety percent of them had ureteral calculi. The differential CrCl of the obstructed kidney (%CrCl was defined as the percentage of CrCl of the obstructed kidney as of the total CrCl, measured 2 weeks after relief of obstruction. The differential renal parenchymal volume of the obstructed kidney (%CTvol was the percentage of renal parenchymal volume as of the total parenchymal volume. The differential USG cortical thickness of the obstructed kidney (%USGcort was the percentage of mean cortical thickness as of the total mean cortical thickness. The Pearson's correlation coefficient (r between %CTvol and %CrCl and that between %USGcort and %CrCl were 0.756 and 0.543 respectively. The regression line was %CrCl = (1.00 x %CTvol - 14.27. The %CTvol

  4. Are Hepatic Portal Venous System Components Distributed Equally in the Liver? A Multidetector Computerized Tomography Study

    Directory of Open Access Journals (Sweden)

    Bülent Yalçın

    2012-12-01

    Full Text Available Objective: We aimed to evaluate the relationships between the splenic index, right and left hepatic lobe volumes, diameters of splenic vein (SV, superior mesenteric vein (SMV and the portal vein (PV by Multidetector Computerized Tomography (MDCT. We also investigated indirect signs of portal venous flow pattern using these parameters.Material and Methods: Following their contrast thoracoabdominal and abdominal 64-MDCT examinations, the images of 100 cases (61 males and 39 females were evaluated retrospectively. For each case, the splenic index, total hepatic volume, left and right hepatic volumes were calculated on the post-contrast portal venous phase (50th sec images. Spearman correlation tests were carried out with the purpose of determining the relationships between the variables. Statistical significance level was set at p<0.005.Results: A statistically significant relation was demonstrated between the diameter of the SMV and right hepatic lobe volume (p<0.0001, and according to Pearson’s correlation analysis, a positive correlation of medium strength (r=0.36 was observed. A positive correlation was demonstrated between the diameter of the splenic vein and left hepatic lobe volume (r=0.36. Statistically significant relation between the diameters of the splenic vein and right hepatic lobe was not observed (p=0.62. A strong correlation between the left hepatic lobe volume and the splenic index (r=0.556 was observed.Conclusion: We observed a positive correlation and a significant relation between the diameter of the SMV and the right hepatic lobe, and a relation between the splenic vein and splenic index and both hepatic lobes. We believe that this situation is related to the streamline flow in the portal vein, and as demonstrated in the literature, the flow in the SMV is directed at the right lobe, whereas the splenic vein empties into the liver homogenously. Our study is the first study in the literature performed by multidetector CT

  5. Imaging in adult patients with acute febrile encephalopathy:What is better, computerized tomography (CT) or magnetic resonance imaging (MRI)?

    Institute of Scientific and Technical Information of China (English)

    Bhalla A; Suri V; Singh P; Varma S; Khandelwal NK

    2012-01-01

    Objective: To compare the efficacy of cranial imaging techniques in adult patients with acute febrile encephalopathy. Methods: We enrolled one hundred and two patients presenting to the emergency with fever of shorter than 15-day duration and altered sensorium. All the patients were subjected to routine investigations, detailed cerebrospinal fluid analysis, computerized tomograms (Non contrast followed by contrast enhanced) and Magnetic resonance imaging of the brain. Final diagnosis was reached after considering the clinical, biochemical findings, imaging results and response to therapy. The positive yield of radiological investigations was compared against the final diagnosis. Results: The patients were divided into three groups. Of these patients, 48 had evidence of meningoencephalitis, 22 patients had pyogenic meningitis, and 20 were combined together in others group. In other 12 patients, a definitive diagnosis could not be made. Only 37% patients were detected to have abnormal computerized tomograms and the commonest abnormality was diffuse edema, which failed to point to an etiological diagnosis. Magnetic resonance imaging was abnormal in 62.75% cases and was able to suggest an etiological diagnosis in 100% cases of cerebral venous thrombosis, tubercular meningitis, 95% cases of meningoencephalitis and 45% with meningitis. Conclusions: Magnetic resonance imaging provides better information than computerized tomography in adult patients with acute febrile encephalopathy.

  6. Comparison of micro-computerized tomography and cone-beam computerized tomography in the detection of accessory canals in primary molars

    Energy Technology Data Exchange (ETDEWEB)

    Acar, Buket; Kamburoglu, Kivanc [Dept. of Dentomaxillofacial Radiology, Faculty of Dentistry, Ankara University, Ankara (Turkmenistan); Tatar, Ilkan [Dept. of Anatomy, Faculty of Medicine, Hacettepe University, Ankara (Turkmenistan); Arikan, Volkan [Dept. of Anatomy, Faculty of Medicine, Hacettepe University, Ankara (Turkmenistan); Celik, Hakan Hamid [Dept. of Pediatric Dentistry, Faculty of Dentistry, Kirikkale Unversity, Ankara (Turkmenistan); Yuksel, Selcen [Dept. of Biostatistics, Faculty of Medicine, Yildirim Beyazit University, Ankara (Turkmenistan); Ozen, Tuncer [Dept. of Dentomaxillofacial Radiology, Gulhane Military Hospital, Dental Clinics, Ankara (Turkmenistan)

    2015-12-15

    This study was performed to compare the accuracy of micro-computed tomography (CT) and cone-beam computed tomography (CBCT) in detecting accessory canals in primary molars. Forty-one extracted human primary first and second molars were embedded in wax blocks and scanned using micro-CT and CBCT. After the images were taken, the samples were processed using a clearing technique and examined under a stereomicroscope in order to establish the gold standard for this study. The specimens were classified into three groups: maxillary molars, mandibular molars with three canals, and mandibular molars with four canals. Differences between the gold standard and the observations made using the imaging methods were calculated using Spearman's rho correlation coefficient test. The presence of accessory canals in micro-CT images of maxillary and mandibular root canals showed a statistically significant correlation with the stereomicroscopic images used as a gold standard. No statistically significant correlation was found between the CBCT findings and the stereomicroscopic images.Although micro-CT is not suitable for clinical use, it provides more detailed information about minor anatomical structures. However, CBCT is convenient for clinical use but may not be capable of adequately analyzing the internal anatomy of primary teeth.

  7. Accuracy of computerized tomography for the evaluation of mandibular sites prior to implant placement

    DEFF Research Database (Denmark)

    Sforza, Nicola Marco; Franchini, Federico; Lamma, Achille

    2007-01-01

    The objective of the present study was to observe the effect of positioning of the mandible on the accuracy of cross-sectional images obtained by reformatting computerized tomographic (CT) scans. An additional aim was to evaluate the ability of a software program (DentalVox, Era Scientific) to re...

  8. Quantification of Soil Physical Properties by Using X-Ray Computerized Tomography (CT) and Standard Laboratory (STD) Methods

    Energy Technology Data Exchange (ETDEWEB)

    Maria Ambert Sanchez

    2003-12-12

    The implementation of x-ray computerized tomography (CT) on agricultural soils has been used in this research to quantify soil physical properties to be compared with standard laboratory (STD) methods. The overall research objective was to more accurately quantify soil physical properties for long-term management systems. Two field studies were conducted at Iowa State University's Northeast Research and Demonstration Farm near Nashua, IA using two different soil management strategies. The first field study was conducted in 1999 using continuous corn crop rotation for soil under chisel plow with no-till treatments. The second study was conducted in 2001 and on soybean crop rotation for the same soil but under chisel plow and no-till practices with wheel track and no-wheel track compaction treatments induced by a tractor-manure wagon. In addition, saturated hydraulic (K{sub s}) conductivity and the convection-dispersion (CDE) model were also applied using long-term soil management systems only during 2001. The results obtained for the 1999 field study revealed no significant differences between treatments and laboratory methods, but significant differences were found at deeper depths of the soil column for tillage treatments. The results for standard laboratory procedure versus CT method showed significant differences at deeper depths for the chisel plow treatment and at the second lower depth for no-till treatment for both laboratory methods. The macroporosity distribution experiment showed significant differences at the two lower depths between tillage practices. Bulk density and percent porosity had significant differences at the two lower depths of the soil column. The results obtained for the 2001 field study showed no significant differences between tillage practices and compaction practices for both laboratory methods, but significant differences between tillage practices with wheel track and no-wheel compaction treatments were found along the soil

  9. Radiation conditions for computerized tomography: determination and comparison; Condicoes de radiacao para tomografia computadorizada: determinacao e comparacoes

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Lucio das Chagas de

    2016-07-01

    Radiology is the practice in which radiation beams, usually radiation X are used to produce an image of the human body in order to obtain a diagnosis, for example, to evaluate a pathological condition by computerized tomography (CT). Although the computerized tomography diagnostic potential is unquestionable, caution must be taken because the doses are almost always higher than the observed in conventional radiology procedures. The ionization chamber used for dosimetry in CT is a unsealed cylindrical chamber with 10 cm and 15 cm of sensitive length. A typical characteristics of this camera is its uniform response to radiation incident at all angles around its axis. The revised edition of IEC 61267 (2005) brought as an innovation the radiation conditions for computed tomography, RQT, that simulate non-attenuated beam and are used in special CT applications. This study aims to establish the necessary conditions to obtain radiation pattern beam computed tomography, RQT, and a calibration laboratory implementation for pencil ionization chambers used in the beam dosimetry produced by these scanners in the Metrology National Laboratory of Ionizing Radiation (LNMRI). In the implementation of RQT conditions we were found that the ratio of kerma rates in the air, with or without additional filtration equivalent to the first HVL (half-value layer), are in accordance with IEC 61267 (2005), which provides a range between 48.5% and 51.5% for each quality. The LNMRI characterized the radiation conditions of RQT series (IEC, 2005), obtaining a percentage of 49.6% for the RQT 8, 50% for the RQT 9 and 50,4% for the RQT 10. With the substitution of the total additional filtration RQT qualities, composed by Al + Cu and by a total filtration composed by copper (Cu) only, it can be seen the emergence of a similar RQT quality named Quality Copper Tomography - QCT. The results of the calibration, the RQT and QCT qualities, had expanded uncertainties with a confidence level 95.45%, less

  10. Using computerized tomography to determine ionospheric structures. Part 1, Notivation and basic approaches

    Energy Technology Data Exchange (ETDEWEB)

    Vittitoe, C.N.

    1993-08-01

    Properties of the ionosphere are reviewed along with its correlations with other geophysical phenomena and with applications of ionospheric studies to communication, navigation, and surveillance systems. Computer tomography is identified as a method to determine the detailed, three-dimensional distribution of electron density within the ionosphere. Several tomography methods are described, with a basic approach illustrated by an example. Limitations are identified.

  11. Diffuse lung neoplasms. Correlation between high resolution computerized tomography and anatomopathology; Neoplasias pulmonares difusas: correlacao da tomografia computadorizada de alta resolucao com a anatomopatologia

    Energy Technology Data Exchange (ETDEWEB)

    Marchiori, Edson [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Dept. de Radiologia; Irion, Klaus L. [Complexo Hospitalar Santa Casa de Porto Alegre, RS (Brazil). Servico de Radiologia do Pavilhao Pereira Filho; Souza Junior, Arthur Soares [Faculdade de Medicina de Sao Jose do Rio Preto, SP (Brazil)]. E-mail: edmarchiori@zipmail.com.br

    2002-08-01

    A short comparative evaluation study between high resolution computerized tomography and anatomopathologic findings is presented. The association of these two diagnostic techniques is discussed as a factor to enhance the accuracy of diffuse lung diseases, such as carcinomatous lymphangitis, Kaposi's Sarcoma, lymphomas, hematogenic metastases, bronchiole-alveolar carcinoma and leukemia. (MAC)

  12. Dose profile measurement in computerized axial tomography equipment using thermoluminescent dosemeters; Medicion del perfil de dosis en equipos de tomografia axial computarizada usando dosimetros termoluminiscentes

    Energy Technology Data Exchange (ETDEWEB)

    Azorin V, J.C.; Falcony, C.; Azorin N, J. [Centro de Investigacion en Ciencia y Tecnologia Avanzada, IPN, 07000 Mexico D.F. (Mexico)

    2000-07-01

    In this work are presented the results about measuring the radiation dose profile in two equipment of computerized axial tomography (Tac). Thermoluminescent dosemeters (Dtl) of LiF, Mg, Cu, P + Ptfe in form of disks were used which were developed and made in Mexico. The results showed that Dtl are appropriated for these type of studies. (Author)

  13. Contrast-enhanced multidetector computerized tomography for odontogenic cysts and cystic-appearing tumors of the jaws: is it useful?

    Science.gov (United States)

    Kakimoto, Naoya; Chindasombatjaroen, Jira; Tomita, Seiki; Shimamoto, Hiroaki; Uchiyama, Yuka; Hasegawa, Yoko; Kishino, Mitsunobu; Murakami, Shumei; Furukawa, Souhei

    2013-01-01

    The purpose of this study was to investigate the usefulness of computerized tomography (CT), particularly contrast-enhanced CT, in differentiation of jaw cysts and cystic-appearing tumors. We retrospectively analyzed contrast-enhanced CT images of 90 patients with odontogenic jaw cysts or cystic-appearing tumors. The lesion size and CT values were measured and the short axis to long axis (S/L) ratio, contrast enhancement (CE) ratio, and standard deviation ratio were calculated. The lesion size and the S/L ratio of keratocystic odontogenic tumors were significantly different from those of radicular cysts and follicular cysts. There were no significant differences in the CE ratio among the lesions. Multidetector CT provided diagnostic information about the size of odontogenic cysts and cystic-appearing tumors of the jaws that was related to the lesion type, but showed no relation between CE ratio and the type of these lesions. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Computerized axial tomography of the chest for visualization of ''absent'' pulmonary arteries

    Energy Technology Data Exchange (ETDEWEB)

    Sondheimer, H.M. (Upstate Medical Center, Syracuse, NY); Oliphant, M.; Schneider, B.; Kavey, R.E.W.; Blackman, M.S.; Parker, F.B. Jr.

    1982-05-01

    To expand the search for central pulmonary arteries in six patients with absence of cardiac-pulmonary continuity, computerized axial tomography (CAT) of the chest was performed. The CAT scans were compared with previous arteriograms and pulmonary vein wedge angiograms. Three patients with type IV truncus arteriosus were studied, and none had a central, right or left pulmonary artery on CAT scan. However, two patients with tetralogy of Fallot with pulmonary atresia and a patent ductus arteriosus to the right lung demonstrated the presence of a left pulmonary artery. In addition, one child with truncus arteriosus with ''absent'' left pulmonary artery demonstrated a left pulmonary artery on the CAT scan. The CAT scan may therefore enhance our ability to search for disconnected pulmonary arteries in children with complex cyanotic congenital heart disease.

  15. Applying computerized adaptive testing to the Negative Acts Questionnaire-Revised: Rasch analysis of workplace bullying.

    Science.gov (United States)

    Ma, Shu-Ching; Chien, Tsair-Wei; Wang, Hsiu-Hung; Li, Yu-Chi; Yui, Mei-Shu

    2014-02-17

    Workplace bullying is a prevalent problem in contemporary work places that has adverse effects on both the victims of bullying and organizations. With the rapid development of computer technology in recent years, there is an urgent need to prove whether item response theory-based computerized adaptive testing (CAT) can be applied to measure exposure to workplace bullying. The purpose of this study was to evaluate the relative efficiency and measurement precision of a CAT-based test for hospital nurses compared to traditional nonadaptive testing (NAT). Under the preliminary conditions of a single domain derived from the scale, a CAT module bullying scale model with polytomously scored items is provided as an example for evaluation purposes. A total of 300 nurses were recruited and responded to the 22-item Negative Acts Questionnaire-Revised (NAQ-R). All NAT (or CAT-selected) items were calibrated with the Rasch rating scale model and all respondents were randomly selected for a comparison of the advantages of CAT and NAT in efficiency and precision by paired t tests and the area under the receiver operating characteristic curve (AUROC). The NAQ-R is a unidimensional construct that can be applied to measure exposure to workplace bullying through CAT-based administration. Nursing measures derived from both tests (CAT and NAT) were highly correlated (r=.97) and their measurement precisions were not statistically different (P=.49) as expected. CAT required fewer items than NAT (an efficiency gain of 32%), suggesting a reduced burden for respondents. There were significant differences in work tenure between the 2 groups (bullied and nonbullied) at a cutoff point of 6 years at 1 worksite. An AUROC of 0.75 (95% CI 0.68-0.79) with logits greater than -4.2 (or >30 in summation) was defined as being highly likely bullied in a workplace. With CAT-based administration of the NAQ-R for nurses, their burden was substantially reduced without compromising measurement precision.

  16. Impact of repeat computerized tomography replans in the radiation therapy of head and neck cancers

    Directory of Open Access Journals (Sweden)

    Virendra Bhandari

    2014-01-01

    Full Text Available Anatomical changes can occur during course of head-and-neck (H and N radiotherapy like tumor shrinkage, decreased edema and/or weight loss. This can lead to discrepancies in planned and delivered dose increasing the dose to organs at risk. A study was conducted to determine the volumetric and dosimetric changes with the help of repeat computed tomography (CT and replanning for selected H and N cancer patients treated with IMRT plans to see for these effects. In 15 patients with primary H and N cancer, a repeat CT scan after 3 rd week of radiotherapy was done when it was clinically indicated and then two plans were generated on repeat CT scan, actual plan (AP planned on repeat CT scan, and hybrid plan (HP, which was generated by applying the first intensity-modulated radiation therapy (IMRT plan (including monitoring units to the images of second CT scan. Both plans (AP and HP on repeat CT scan were compared for volumetric and dosimetric parameter. The mean variation in volumes between CT and repeat CT were 44.32 cc, 82.2 cc, and 149.83 cc for gross tumor volume (GTV, clinical target volumes (CTV, and planning target volume (PTV, respectively. Mean conformity index and homogeneity index was 0.68 and 1.07, respectively for AP and 0.5 and 1.16, respectively for HP. Mean D 95 and D 99 of PTV was 97.92% (standard deviation, SD 2.32 and 93.4% (SD 3.75, respectively for AP and 92.8% (SD 3.83 and 82.8% (SD 8.0, respectively for HP. Increase in mean doses to right parotid, left parotid, spine, and brainstem were 5.56 Gy (D mean , 3.28 Gy (D mean , 1.25 Gy (D max , and 3.88 Gy (D max , respectively in HP compared to AP. Repeat CT and replanning reduces the chance of discrepancies in delivered dose due to volume changes and also improves coverage to target volume and further reduces dose to organ at risk.

  17. The potential of positron emission tomography/computerized tomography (PET/CT) scanning as a detector of high-risk patients with oral infection during preoperative staging.

    Science.gov (United States)

    Yamashiro, Keisuke; Nakano, Makoto; Sawaki, Koichi; Okazaki, Fumihiko; Hirata, Yasuhisa; Takashiba, Shogo

    2016-08-01

    It is sometimes difficult to determine during the preoperative period whether patients have oral infections; these patients need treatment to prevent oral infection-related complications from arising during medical therapies, such as cancer therapy and surgery. One of the reasons for this difficulty is that basic medical tests do not identify oral infections, including periodontitis and periapical periodontitis. In this report, we investigated the potential of positron emission tomography/computerized tomography (PET/CT) as a diagnostic tool in these patients. We evaluated eight patients during the preoperative period. All patients underwent PET/CT scanning and were identified as having the signs of oral infection, as evidenced by (18)F-fludeoxyglucose (FDG) localization in the oral regions. Periodontal examination and orthopantomogram evaluation showed severe infection or bone resorption in the oral regions. (18)F-FDG was localized in oral lesions, such as severe periodontitis, apical periodontitis, and pericoronitis of the third molar. The densities of (18)F-FDG were proportional to the degree of inflammation. PET/CT is a potential diagnostic tool for oral infections. It may be particularly useful in patients during preoperative staging, as they frequently undergo scanning at this time, and those identified as having oral infections at this time require treatment before cancer therapy or surgery. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Applying Computerized Adaptive Testing to the Four-Dimensional Symptom Questionnaire (4DSQ): A Simulation Study

    Science.gov (United States)

    de Beurs, Derek P; Terluin, Berend; Verhaak, Peter F

    2017-01-01

    Background Efficient screening questionnaires are useful in general practice. Computerized adaptive testing (CAT) is a method to improve the efficiency of questionnaires, as only the items that are particularly informative for a certain responder are dynamically selected. Objective The objective of this study was to test whether CAT could improve the efficiency of the Four-Dimensional Symptom Questionnaire (4DSQ), a frequently used self-report questionnaire designed to assess common psychosocial problems in general practice. Methods A simulation study was conducted using a sample of Dutch patients visiting a general practitioner (GP) with psychological problems (n=379). Responders completed a paper-and-pencil version of the 50-item 4DSQ and a psychometric evaluation was performed to check if the data agreed with item response theory (IRT) assumptions. Next, a CAT simulation was performed for each of the four 4DSQ scales (distress, depression, anxiety, and somatization), based on the given responses as if they had been collected through CAT. The following two stopping rules were applied for the administration of items: (1) stop if measurement precision is below a predefined level, or (2) stop if more than half of the items of the subscale are administered. Results In general, the items of each of the four scales agreed with IRT assumptions. Application of the first stopping rule reduced the length of the questionnaire by 38% (from 50 to 31 items on average). When the second stopping rule was also applied, the total number of items could be reduced by 56% (from 50 to 22 items on average). Conclusions CAT seems useful for improving the efficiency of the 4DSQ by 56% without losing a considerable amount of measurement precision. The CAT version of the 4DSQ may be useful as part of an online assessment to investigate the severity of mental health problems of patients visiting a GP. This simulation study is the first step needed for the development a CAT version of the 4

  19. Applying Computerized Adaptive Testing to the Negative Acts Questionnaire-Revised: Rasch Analysis of Workplace Bullying

    Science.gov (United States)

    Ma, Shu-Ching; Li, Yu-Chi; Yui, Mei-Shu

    2014-01-01

    Background Workplace bullying is a prevalent problem in contemporary work places that has adverse effects on both the victims of bullying and organizations. With the rapid development of computer technology in recent years, there is an urgent need to prove whether item response theory–based computerized adaptive testing (CAT) can be applied to measure exposure to workplace bullying. Objective The purpose of this study was to evaluate the relative efficiency and measurement precision of a CAT-based test for hospital nurses compared to traditional nonadaptive testing (NAT). Under the preliminary conditions of a single domain derived from the scale, a CAT module bullying scale model with polytomously scored items is provided as an example for evaluation purposes. Methods A total of 300 nurses were recruited and responded to the 22-item Negative Acts Questionnaire-Revised (NAQ-R). All NAT (or CAT-selected) items were calibrated with the Rasch rating scale model and all respondents were randomly selected for a comparison of the advantages of CAT and NAT in efficiency and precision by paired t tests and the area under the receiver operating characteristic curve (AUROC). Results The NAQ-R is a unidimensional construct that can be applied to measure exposure to workplace bullying through CAT-based administration. Nursing measures derived from both tests (CAT and NAT) were highly correlated (r=.97) and their measurement precisions were not statistically different (P=.49) as expected. CAT required fewer items than NAT (an efficiency gain of 32%), suggesting a reduced burden for respondents. There were significant differences in work tenure between the 2 groups (bullied and nonbullied) at a cutoff point of 6 years at 1 worksite. An AUROC of 0.75 (95% CI 0.68-0.79) with logits greater than –4.2 (or >30 in summation) was defined as being highly likely bullied in a workplace. Conclusions With CAT-based administration of the NAQ-R for nurses, their burden was substantially

  20. Evaluation of the soil-seed environment through computerized tomography; Avaliacao do ambiente solo-semente por meio da tomografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Modolo, Alcir Jose [Universidade Tecnologica Federal do Parana (UTFPR), Pato Branco, PR (Brazil)). E-mail: alcir@ufpr.edu.br; Fernandes, Haroldo Carlos [Universidade Federal de Vicosa (UFV), MG (Brazil). Dept. de Engenharia Agricola]. E-mail: haroldo@ufv.br; Naime, Joao de Mendonca [Embrapa Instrumentacao Agropecuaria, Sao Carlos, SP (Brazil)]. E-mail: naime@cnpdia.embrapa.br; Schaefer, Carlos Ernesto G.R. [Universidade Federal de Vicosa (UFV), MG (Brazil). Dept. de Solos]. E-mail: carlos.schaefer@ufv.br; Santos, Nerilson Terra [Universidade Federal de Vicosa (UFV), MG (Brazil). Dept. de Informatica]. E-mail: nsantos@ufv.br; Silveira, Joao Cleber Modernel da [Universidade Federal de Vicosa (UFV), MG (Brazil). Mecanizacao Agricola]. E-mail: jcmodernel@uol.com.br

    2008-03-15

    The physical conditioning of the soil around seeds is of great importance for an adequate initial development of a crop, ensuring a healthy plant population. A suitable soil-seed contact is a prerequisite for a fast crop germination and good establishment. In this study, computerized tomography of millimeter resolution was used to determine the soil-seed environment in a no tillage system, immediately after soybean planting. A split plot design was used, in which the plots consisted of three contents of soil water, corresponding to 0.27; 0,31 and 0.36 kg kg{sup -1}, respectively, and the split plots of four load levels applied by the compaction wheel, corresponding to 0, 50, 90 and 140 N, respectively. It was used a random block design, with four replications. The medium soil density in the seed area and the medium density profile in the sowing furrow were evaluated. According to the results, it may be concluded that: the loads applied by the compaction wheel increased soil density at the vertical planting level beneath planting depth as compared with values obtained before planting, and; the combination of wheel loads and soil water contents did not influence the mean soil density in the seed area. (author)

  1. [A quantitative evaluation of brain computerized tomography in children using color image analyzer].

    Science.gov (United States)

    Yamatani, M; Naganuma, Y; Hongoh, K; Murakami, M; Konishi, T; Okada, T

    1989-11-01

    We attempted the quantitative analysis of brain computerized tomographic scans in children using Color Image Analyzer. A consecutive series of 167 computerized tomographic scans were reviewed. Areas of subarachnoid spaces, cavums, ventricles and cerebellums were measured on three slices: A slice is at the level of head of caudate nucleus, anterior horn of lateral ventricle and third ventricle. B slice is at the level of body of lateral ventricle. C slice is at the level of sella turcica and pons. We investigated these values compared with Evans ratio, Cella Media Index, cerebellar atrophy score and visually evaluations. Serial brain CT scans of eight patient with infantile spasms were also evaluated for the assessment of the brain shrinkage after ACTH therapy. 1) The ratios of the subarachnoid space/the intracranial area on A and B slices (SAS A%, SAS B%) were significantly higher in the patients of severe brain atrophy. 2) There were linear relationship between Evans ratio and SAS A% (r = 0.405, p less than 0.001), Cella Media Index and the ratio of the lateral ventricles/the intracranial areas on B slice (r = -0.501, p less than 0.001), and the cerebellar atrophy score by Une and SAS C% (r = 0.369, p less than 0.001). 3) In the normal patients, the values of SAS A% and SAS B% were much greater in less than 1.5 years old children. These results suggest that the trend of CT findings related to age may reflect physiological changes of the space between the skull and the brain with age. 4) Brain shrinkage after ACTH therapy was more pronounced in the subarachnoid space than the ventricle.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Use of computerized tomography for diagnosis and follow-up after endodontic surgery: clinical case report with 8 years of follow-up.

    Science.gov (United States)

    Tanomaru-Filho, Mario; Lima, Regina K P; Nakazone, Paula A; Tanomaru, Juliane M G

    2010-04-01

    Computerized tomography (CT) is a valuable tool for diagnosis and planning in conventional and surgical endodontic therapy. This case report describes the use of CT in the diagnosis of a periapical lesion undetected by periapical radiography in the mandibular molar area. The CT also showed a possible mesial root perforation associated with the lesion. Following CT, surgical planning, periradicular curettage, and sealing of the root perforation were performed. Eight years after surgery, cone beam CT revealed periapical bone repair. Computerized tomography can be an important resource for diagnosis and planning in conventional and surgical endodontic therapy, as well as for evaluation of post-treatment bone repair. Copyright 2010 Mosby, Inc. All rights reserved.

  3. Prognosis of the computerized tomography in the severe head injury. Valor pronostico de la tomografia axial computada (TC) en los traumatismos craneoencefalicos severos

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Nieto, J.J.; Lorenzo Dominguez, M.T.; Martin Sanchez, M.J.; Sanchez Gonzalez, E.

    1991-01-01

    A prospective study is made with sixty five people affected of severe head injury, that is to say, with eight or less points in the Glasgow Coma Scale (GCS), when they get to the hospital. They are studied by computerized tomography at admission, and three and seven days after arrival. In this way, we appraise the type of the lesion, its intensity and the possible prognosis, considering in the last case three features: a) ventricular collapse; b) the mean line structure s shift; and c) effects on perimesencephalic cistern. The findings were parametized and we were able to introduce into the computer program relationships between these findings and the end results. These last ones were appraised through the Glasgow Outcome Scale (GOS). We could show that certain findings in computerized tomography scans have an unavoidable prognosis while as others have a more favorable prognosis. (Author)

  4. Morphometric evaluation of subaxial cervical spine using multi-detector computerized tomography (MD-CT) scan: the consideration for cervical pedicle screws fixation

    OpenAIRE

    Chanplakorn, Pongsthorn; Kraiwattanapong, Chaiwat; Aroonjarattham, Kitti; Leelapattana, Pittavat; Keorochana, Gun; Jaovisidha, Suphaneewan; Wajanavisit, Wiwat

    2014-01-01

    Background Cervical pedicle screw (CPS) insertion is a technically demanding procedure. The quantitative understanding of cervical pedicle morphology, especially the narrowest part of cervical pedicle or isthmus, would minimize the risk of catastrophic damage to surrounding neurovascular structures and improve surgical outcome. The aim of this study was to investigate morphology and quantify cortical thickness of the cervical isthmus by using Multi-detector Computerized Tomography (MD-CT) sca...

  5. Dose profile study on computerized tomography scanning of skull with simulator object; Estudo do perfil de dose em varreduras de TC de cranio com objeto simulador

    Energy Technology Data Exchange (ETDEWEB)

    Mourao, A.P., E-mail: aprata@des.cefetmg.b [Centro Federal de Educacao Tecnologica de Minas Gerais (CEFET/MG), Belo Horizonte, MG (Brazil). Nucleo de Engenharia Hospitalar; Alonso, Thessa C.; Silva, Teogenes A. da, E-mail: alonso@cdtn.b, E-mail: silvata@@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2011-10-26

    This work presents a comparison among the dose profiles in scanning of computerized tomography of a simulator object of PMMA in its periphery region. To obtain the deposited dose at the PMMA thermoluminescent dosemeters were used positioned at the interior of PMMA simulated object longitudinal to periphery and at the center of cylinder (positions denominated North, South, East, West and Center). Eight scanning were performed of simulator object using the routine protocol for skull in eight different services of radiodiagnostic by TC

  6. Pseudomeningocele in communication with the facet joint: demonstration by computerized tomography-arthrography

    Energy Technology Data Exchange (ETDEWEB)

    Ganiyusufoglu, Kursat; Ozturk, Cagatay; Sirvanci, Mustafa; Aksu, Neslihan; Hamzaoglu, Azmi [Florence Nightingale Hospital, Istanbul Bilim University, Istanbul Spine Center, Istanbul (Turkey)

    2008-08-15

    Pseudomeningocele is an uncommon but well-known complication of lumbar spine operations. Although it is mostly asymptomatic and managed conservatively in most cases, it is claimed as a causative factor of failed back surgery syndrome and requires surgery in some cases. Usually, its diagnosis is confidently done with imaging modalities such as magnetic resonance imaging, computed tomography and myelography. In this report, we describe a case of pseudomeningocele that communicated with a facet joint. The diagnostic approach for this unusual lesion and its probable causes are discussed. (orig.)

  7. Circular gratings' moiré effect for projection measurement in volume optical computerized tomography with two-step phase-shifting method

    Science.gov (United States)

    Wang, Jia; Song, Yang; Li, Zhen-hua; He, An-zhi

    2012-11-01

    Volume optical computerized tomography (VOCT), which can realize real 3D measurement rather than traditional 2D OCT, has great superiority in quantitatively measuring the thermo physical parameters of transient flow field. Among the refractive index reconstruction techniques, filtered back-projection (FBP) method performs better than algebraic reconstruction techniques (ARTs) with higher accuracy and computationally efficient. In order to apply FBP to VOCT, the radial second-order derivative of projection wave front passes through the tested phase object should be obtained firstly. In this paper, a projection device with two circular gratings is established. In particular, owing to an inherent phase shift exists between moiré fringes of +1 and -1 diffraction orders, a two-step phase-shifting algorithm is utilized to extract the wave front's radial first-order derivative which is contained in the moiré fringes. The reliability of the two-step phase-shifting algorithm is proved by a computer simulation. Finally, the radial first-order derivative of wave front passing through a propane flame is measured and retrieved by these methods.

  8. Computerized tomography quality control program; Programa de controle da qualidade em tomografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Tiecher, Maria Ester S.; Ferreira, Nadya Maria P.D. [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil); Carlos, Marcia Terezinha [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil)

    1999-11-01

    Computed Tomography, CT, is a practice used in radiodiagnosis, based on radiation (x-rays) interaction with matter and image reconstruction. No doubt there are great benefits to this procedure, but some problems can be found with it. Little attention has been paid to the high incident doses which patients undergo during these tests. This work is intended to develop a quality control program over CT. The methodology evaluates the performance of the CT by studying the image`s physical parameters. It also verifies the effectiveness of the beam according to the measurement of the doses, Computed Tomography Dose Index. In this case, this is done by using measurements in simulators (phantoms). Internationally established tests were implemented: high resolution and low contrast, linearity, uniformity of CT numbers, noise, slice thickness and artifacts. All the tests were performed at the Hospital Central do Exercito. Doses measurements were done using a pencil ionization chamber and phantom heads and bodies, supplied by the equipment`s manufacturer. The obtained results showed the efficiency of the methodology allowing for the correction of some drawbacks without deviating from the routine procedures. (author) 12 refs., 4 figs., 4 tabs.

  9. Multislice computerized tomography of the heart and coronary arteries; Exploration par tomodensitometrie multidetecteur du coeur et des arteres coronaires

    Energy Technology Data Exchange (ETDEWEB)

    Dacher, J.N.; Bertrand, D.; Belhiba, H. [Centre Hospitalier Universitaire, Service de Radiologie, Dept. d' Imagerie Medicale, LITIS EA 4108, Hopital Charles-Nicolle, 76 - Rouen (France); Tron, Ch. [Centre Hospitalier Universitaire, Service de Cardiologie, Hopital Charles-Nicolle, 76 - Rouen (France)

    2007-12-15

    Due to its excellent spatial and temporal resolution, multislice computerized tomography (M.S.C.T.) allows visualizing the heart and coronary arteries. Although the indications of M.S.C.T. did not reach a consensus level yet, some trends can be stated. The advantages and limitations of M.S.C.T. in cardiac exploration are summarized in this article. The indications are mainly based on the excellent negative predictive value of M.S.C.T. regarding coronary artery disease. Hence, patients at low to moderate risk of coronary artery disease (CAD) mostly benefit of the technique. M.S.C.T. can be an alternate examination in case of non feasible or non contributive stress test. M.S.C.T. is highly contributive in the ostial analysis, in detecting abnormal coronary implantation or course, in assessing a reimplanted artery or in analysing bypass grafts. M.S.C.T. remains limited in patients with heavily calcified coronary arteries, and in patients with stented distal arteries. (authors)

  10. Computerized tomography findings in Fahr's syndrome Achados da tomografia computadorizada na síndrome de Fahr

    Directory of Open Access Journals (Sweden)

    Andréia V. Faria

    2004-09-01

    Full Text Available We analyzed computerized tomography (CT findings in six patients with Fahr's syndrome. They presented calcifications in basal ganglia, dentate nucleus, subcortical region and semioval center, due to alteration in calcium metabolism or due to senile relative hypoxemic state. The image pattern was not strictly related with etiology, although some differences in dystrophic senile calcifications (the only one present in semioval center and absent in subcortical region. CT is an easy exam, has maximum sensitivity and allows diagnosis, contributing to early treatment of many etiologies of Fahr's syndrome.Analisamos os achados de tomografia computadorizada (TC de seis pacientes com síndrome de Fahr. Eles apresentaram calcificações nos gânglios da base, núcleo denteado, região subcortical e centro semi-oval, devidas a distúrbios no metabolismo do cálcio ou a estado de hipóxia relativa, por senilidade. O padrão de imagem não apresenta relação clara com a etiologia, apesar de algumas diferenças no caso das calcificações distróficas senis (as únicas presentes nos centros semi-ovais e ausentes na região subcortical. TC é um exame de fácil realização, máxima sensibilidade e permite o diagnóstico, contribuindo para o tratamento precoce de muitas das etiologias da síndrome de Fahr.

  11. Dopamine transporter single-photon emission computerized tomography supports diagnosis of akinetic crisis of parkinsonism and of neuroleptic malignant syndrome.

    Science.gov (United States)

    Martino, G; Capasso, M; Nasuti, M; Bonanni, L; Onofrj, M; Thomas, A

    2015-04-01

    Akinetic crisis (AC) is akin to neuroleptic malignant syndrome (NMS) and is the most severe and possibly lethal complication of parkinsonism. Diagnosis is today based only on clinical assessments yet is often marred by concomitant precipitating factors. Our purpose is to evidence that AC and NMS can be reliably evidenced by FP/CIT single-photon emission computerized tomography (SPECT) performed during the crisis. Prospective cohort evaluation in 6 patients. In 5 patients, affected by Parkinson disease or Lewy body dementia, the crisis was categorized as AC. One was diagnosed as having NMS because of exposure to risperidone. In all FP/CIT, SPECT was performed in the acute phase. SPECT was repeated 3 to 6 months after the acute event in 5 patients. Visual assessments and semiquantitative evaluations of binding potentials (BPs) were used. To exclude the interference of emergency treatments, FP/CIT BP was also evaluated in 4 patients currently treated with apomorphine. During AC or NMS, BP values in caudate and putamen were reduced by 95% to 80%, to noise level with a nearly complete loss of striatum dopamine transporter-binding, corresponding to the "burst striatum" pattern. The follow-up re-evaluation in surviving patients showed a recovery of values to the range expected for Parkinsonisms of same disease duration. No binding effects of apomorphine were observed. By showing the outstanding binding reduction, presynaptic dopamine transporter ligand can provide instrumental evidence of AC in Parkinsonism and NMS.

  12. A quantitative evaluation of brain computerized tomography in children using color image analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Yamatani, Miwa; Naganuma, Yoshihiro; Hongoh, Kazuhisa; Murakami, Miyako; Konishi, Tohru; Okada, Toshio (Toyama Medical and Pharmaceutifal Univ. (Japan))

    1989-11-01

    We attempted the quantitative analysis of brain computerized tomographic (CT) scans in children using color image analyzer. A consecutive series of 167 CT scans were reviewed. Areas of subarachnoid space, cavum, ventricle and cerebellum were measured on three slices: A slice is at the level of head of caudate nucleus, anterior horn of lateral ventricle and third ventricle. B slice is at the level of body of lateral ventricle. B slice is at the level of body of lateral ventricle. C slice is at the level of sella turcica and pons. We investigated these values compared with Evans ratio, Cella Media Index, cerebellar atrophy score and visual evaluation. Serial brain CT scans of 8 patients with infantile spasm were evaluated for the assessment of the brain shrinkage after ACTH therapy. The ratios of subarachnoid space/intracranial area on A and B slices (SAS A%, SAS B%) were significantly higher in the patients with severe brain atrophy. There were linear relationships between Evans ratio and SAS A%(r=0.405, p<0.001), Cella Media Index and the ratio of the lateral ventricle/intracranial area on B slice (r=-0.501, p<0.001), and the cerebellar atrophy score by Une and SAS C% (r=0.369, p<0.001). In the normal patients, the values of SAS A% and SAS B% were much greater in less than 1.5 years old children. These results suggest that the trend of CT findings related to age may reflect physiological changes of the space between the skull and the brain with age. Brain shrinkage after ACTH therapy was more pronounced in the subarachnoid space than the ventricle. The prognosis of infantile spasm concerning convulsive attacks was relatively good in patients with severely brain shrinkage after ACTH therapy. Quantitative analysis of brain CT scans seemed to be available to clinical and objective evaluations. (author).

  13. Cone beam computerized tomography: basics for digital planning in oral surgery and implantology.

    Science.gov (United States)

    Rugani, P; Kirnbauer, B; Arnetzl, G V; Jakse, N

    2009-01-01

    For the diagnosis of bone pathology, planning of complex implant-supported prosthetic restorations, and guaranteeing oral surgery that is as safe and free of complications as possible, a three-dimensional radiological display is frequently indicated. Cone beam computed tomography (CBCT), which can cover a large part of the indications of the dental and oral surgical spectrum, represents an alternative to computed tomography. Moreover, the method offers the advantage that it can also be used in the dental practice, taking the existing radiation protection regulations into account. This guarantees optimum patient and user friendliness, because referral to a specialized CT facility is thus no longer necessary in most cases. In the first 12 months of the trials of the Planmeca Promax 3D at the Department of Dental Surgery and Radiology of the University Clinic for Oral and Maxillofacial Medicine in Graz, the overwhelming majority of referrals for CBCT (almost 90%) was concerned with the field of oral surgery and implantology. Oral surgical questions mainly covered aspects of wisdom tooth anatomy, position of impacted canines, premolars, and mesiodents, as well as cystic lesions. Diagnoses of the maxillary sinuses and the area of tooth preservation represented further indications. Apart from diagnostic purposes, the objective of the referrals was facilitating optimum preparation for the pending operation. In the area of implantology, this was combined frequently with pre- or post-augmentative three-dimensional digital therapy planning. CBCT showed good results in the display of hard tissue structures and can be integrated without difficulty in the daily clinical routine.

  14. Polarization-sensitive optical coherence tomography applied to intervertebral disk

    Science.gov (United States)

    Matcher, Stephen J.; Winlove, Peter; Gangnus, Sergei V.

    2003-07-01

    Polarization-sensitive optical coherence tomography (PSOCT) is a powerful new optical imaging modality that is sensitive to the birefringence properties of tissues. It thus has potential applications in studying the large-scale ordering of collagen fibers within connective tisues and changes related to pathology. As a tissue for study by PSOCT, intervertebral disk respresents an interesting system as the collagen organization is believed to show pronounced variations with depth, on a spatial scale of about 100 μm. We have used a polarization-sensitive optical coherence tomography system to measure the birefringence properties of bovine caudal intervertebral disk and compared this with equine flexor tendon. The result for equine tendon, δ = (3.0 +/- 0.5)x10-3 at 1.3 μm, is in broad agreement with values reported for bovine tendon, while bovine intervertebral disk displays a birefringence of about half this, δ = 1.2 x 10-3 at 1.3 μm. While tendon appears to show a uniform fast-axis over 0.8 mm depth, intervertebral disk shows image contrast at all orientations relative to a linearly polarized input beam, suggesting a variation in fast-axis orientation with depth. These initial results suggest that PSOCT could be a useful tool to study collagen organization within this tissue and its variation with applied load and disease.

  15. Signs and symptoms after temporomandibular joint washing and cannula placement assessed by cone beam computerized tomography.

    Science.gov (United States)

    Kristensen, Kasper Dahl; Stoustrup, Peter; Alstergren, Per; Küseler, Annelise; Herlin, Troels; Pedersen, Thomas Klit

    2015-08-01

    Analyses of temporomandibular joint synovial fluid using the hydroxocobalamin push-pull technique are increasingly used. However, objective complications and subjective experiences from this procedure have not been described. Firstly, this study aimed to describe discomfort and potential side-effects of this method with special emphasis on symptoms related to the arthrocentesis to be used for future patient information and Ethical Committee applications. Secondly, this study aimed to evaluate the use of cone beam computed tomography (CBCT) as control of intra-capsular cannula placement. Twenty healthy, young adult volunteers were included. Extensive objective and subjective questionnaires were completed before and 14 days after the synovial fluid sampling. With the cannula inside the joints a CBCT was done to investigate if this procedure can be used to verify intra-capsular cannula position. The subjective findings: Most subjects did experience mild pain or discomfort post-operatively. In 12 of 20 subjects symptoms had resolved after 2 days and no subjects had symptoms for more than a week. The longer lasting symptoms were mainly transient joint sounds on mandibular movement. Objective findings: 14 days after the sampling mandibular protrusion had improved 1 mm, but all other objective measures were equal compared to baseline. CBCT showed a large variation in cannula position and no conclusions could be drawn from this. The hydroxocobalamin push-pull synovial fluid sampling may cause minor, transient symptoms. CBCT does not seem to provide any clinical benefits concerning the correct cannula position in relation to the upper joint compartment and disc.

  16. [Diagnostic significance and therapeutic consequences of computerized tomography (patient outcome research). II: General surgical diagnosis].

    Science.gov (United States)

    Hidajat, N; Schröder, R J; Vogl, T; Neuhaus, P; Schedel, H; Felix, R

    1995-03-01

    Computed tomography is one of the indispensable diagnostic methods in the treatment of many surgical patients. On the other hand, the high cost of equipment and effort and the expensive examination must be taken into account. For the purposes of a patient-outcome study all CT examinations of surgical patients performed in March to May 1993 were analysed under medical and economic aspects. 49% of the 210 examinations (153 patients) were primary examinations, 51% served as control examinations. In 61% the diagnosis was already known, but additional information with decisive influence on the further treatment was obtained. In 17% the supposed diagnosis could be verified and in 22% it was rejected. In 170 examinations (81%) the necessity of an operation was the question. 53% of all CT examinations revealed that indication for an operation was absent, and in 28% an operative intervention was performed. The CT examination of surgical patients cannot be substituted by lower-cost methods. The use of an efficient planning of the therapeutic procedures, shortcutting of many other diagnostic examinations, and the avoidance of unnecessary surgical interventions result in shortening the duration of treatment and are instrumental in reducing the total treatment cost.

  17. Assessment of extracranial-intracranial bypass patency with 64-slice multidetector computerized tomography angiography

    Energy Technology Data Exchange (ETDEWEB)

    Thines, Laurent [Lille University Hospital, Department of Neurosurgery, Lille (France); Toronto Western Hospital, Division of Neurosurgery and Department of Surgery, Toronto, ON (Canada); Toronto Western Hospital, University of Toronto Brain Vascular Malformation Study Group, Toronto, ON (Canada); Agid, Ronit; Da Costa, Leodante; Terbrugge, Karel G. [Toronto Western Hospital, Division of Neuroradiology, Department of Medical Imaging, Toronto, ON (Canada); Toronto Western Hospital, University of Toronto Brain Vascular Malformation Study Group, Toronto, ON (Canada); Dehdashti, Amir R.; Wallace, M.C.; Tymianski, Michael [Toronto Western Hospital, Division of Neurosurgery and Department of Surgery, Toronto, ON (Canada); Toronto Western Hospital, University of Toronto Brain Vascular Malformation Study Group, Toronto, ON (Canada)

    2009-08-15

    Extracranial-intracranial (EC/IC) bypass is a useful procedure for the treatment of cerebral vascular insufficiency or complex aneurysms. We explored the role of multidetector computed tomography angiography (MDCTA), instead of digital subtraction angiography (DSA), for the postoperative assessment of EC/IC bypass patency. We retrospectively analyzed a consecutive series of 21 MDCTAs from 17 patients that underwent 25 direct or indirect EC/IC bypass procedures between April 2003 and November 2007. Conventional DSA was available for comparison in 13 cases. MDCTA used a 64-slice MDCT scanner (Aquilion 64, Toshiba). The proximal and distal patencies were analyzed independently on MDCTA and DSA by a neuroradiologist and a neurosurgeon. The bypass was considered patent when the entire donor vessel was opacified without discontinuity from proximal to distal ends and was visibly in contact with the recipient vessel. MDCTA depicted the patency status in every patient. Bypasses were patent in 22 cases, stenosed in one, and occluded in two. DSA always confirmed the results of the MDCTA (sensitivity = 100%, 95% CI = 0.655-1.0; specificity 100%, 95% CI = 0.05-1.0). MDCTA is a non-invasive and accurate exam to assess the postoperative EC/IC bypass patency and is a promising technique in routine follow-up. (orig.)

  18. Dose assessment in pediatric computerized tomography; Avaliacao de doses em tomografia computadorizada pediatrica

    Energy Technology Data Exchange (ETDEWEB)

    Vilarinho, Luisa Maria Auredine Lima

    2004-07-01

    The objective of this work was the evaluation of radiation doses in paediatric computed tomography scans, considering the high doses usually involved and the absence of any previous evaluation in Brazil. Dose values were determined for skull and abdomen examinations, for different age ranges, by using the radiographic techniques routinely used in the clinical centers investigated. Measurements were done using pencil shape ionization chambers inserted in polymethylmethacrylate (PMMA) phantoms. These were compact phantoms of different diameters were specially designed and constructed for this work, which simulate different age ranges. Comparison of results with published values showed that doses were lower than the diagnostic reference levels established to adults exams by the European Commission. Nevertheless, doses in paediatric phantoms were higher than those obtained in adult phantoms. The paediatric dose values obtained in Hospitals A and B were lower than the reference level (DRL) adopted by SHIMPTON for different age ranges. In the range 0 - 0.5 year (neonatal), the values of DLP in Hospital B were 94 por cent superior to the DRL For the 10 years old children the values of CTDI{sub w} obtained were inferior in 89 por cent for skull and 83 por cent for abdomen examinations, compared to the values published by SHRIMPTON and WALL. Our measured CTDI{sub w} values were inferior to the values presented for SHRIMPTON and HUDA, for all the age ranges and types of examinations. It was observed that the normalized dose descriptors values in children in the neonatal range were always superior to the values of doses for the adult patient. In abdomen examinations, the difference was approximately 90% for the effective dose (E) and of 57%.for CTDI{sub w} . (author)

  19. The development and role of megavoltage cone beam computerized tomography in radiation oncology

    Science.gov (United States)

    Morin, Olivier

    External beam radiation therapy has now the ability to deliver doses that conform tightly to a tumor volume. The steep dose gradients planned in these treatments make it increasingly important to reproduce the patient position and anatomy at each treatment fraction. For this reason, considerable research now focuses on in-room three-dimensional imaging. This thesis describes the first clinical megavoltage cone beam computed tomography (MVCBCT) system, which utilizes a conventional linear accelerator equipped with an amorphous silicon flat panel detector. The document covers the system development and investigation of its clinical applications over the last 4-5 years. The physical performance of the system was evaluated and optimized for soft-tissue contrast resolution leading to recommendations of imaging protocols to use for specific clinical applications and body sites. MVCBCT images can resolve differences of 5% in electron density for a mean dose of 9 cGy. Hence, the image quality of this system is sufficient to differentiate some soft-tissue structures. The absolute positioning accuracy with MVCBCT is better than 1 mm. The accuracy of isodose lines calculated using MVCBCT images of head and neck patients is within 3% and 3 mm. The system shows excellent stability in image quality, CT# calibration, radiation exposure and absolute positioning over a period of 8 months. A procedure for MVCBCT quality assurance was developed. In our clinic, MVCBCT has been used to detect non rigid spinal cord distortions, to position a patient with a paraspinous tumor close to metallic hardware, to position prostate cancer patients using gold markers or soft-tissue landmarks, to monitor head and neck anatomical changes and their dosimetric consequences, and to complement the convention CT for treatment planning in presence of metallic implants. MVCBCT imaging is changing the clinical practice of our department by increasingly revealing patient-specific errors. New verification

  20. Utility of mobile devices in the computerized tomography evaluation of intracranial hemorrhage

    Directory of Open Access Journals (Sweden)

    Sridhar G Panughpath

    2013-01-01

    Full Text Available Aim: To evaluate the utility of a mobile device to detect and assess intracranial hemorrhage (ICH on head computed tomographys (CT performed in the emergency setting. Materials and Methods: 100 head CT scans were randomly selected from our emergency radiology database and anonymized for patient demographics and clinical history. The studies were independently interpreted by two experienced radiologists in a blinded manner, initially on a mobile device (iPad, Apple computers and subsequently, at an interval of one week, on a regular desktop workstation. Evaluation was directed towards detection, localization and characterization of hemorrhage. The results were assessed for accuracy, sensitivity, specificity and positive predictive value. Statistical significance was ascertained using Fisher′s exact test. Results: 27 of the examinations were positive for ICH, of which 11 had multiple hemorrhages. Of these there were 17 subdural, 18 intraparenchymal, 8 subarachnoid, 4 intraventricular and 2 extradural hemorrhages. In 96 of the studies there was complete concurrence between the iPad and desktop interpretations for both radiologists. Of 49 hemorrhages, 48 were accurately detected on the iPad by one of the radiologists. In the remaining case, a tiny intraventricular hemorrhage was missed by both radiologists on the iPad as well as on the workstation, indicating that the miss was more likely related to the very small size of the hemorrhage than the viewer used. Conclusion: We conclude that in the emergency setting, a mobile device with appropriate web-based pictue archiving and communication system (PACS is effective in the detection of intracranial hemorrhage present on head CT.

  1. Micro-computerized tomography assessment of fluorescence aided caries excavation (FACE) technology: comparison with three other caries removal techniques.

    Science.gov (United States)

    Zhang, X; Tu, R; Yin, W; Zhou, X; Li, X; Hu, D

    2013-12-01

    The aim of this study was to determine the caries removal effectiveness (CRE) and minimal invasiveness potential (MIP) of four dentine caries removal methods. After carious molars were scanned using micro-computerized tomography (micro-CT), dentine caries were removed by fluorescence aided caries excavation (FACE) technology, laser induced fluorescence (LIF), chemomechanical excavation (CME), and conventional excavation (CE). Micro-CT was then repeated. CRE was determined based on the volume of residual caries/initial caries (RC/IC) and the mean mineral density (MD) at the cavity floor. MIP was determined by measuring the volume of the prepared cavity/initial cavity (PC/IC). Among the four groups, the LIF group had the smallest RC/IC (0.08), the highest mean MD at the cavity floor (1.32 g/cm(3) ) and the highest MIP (4.47). The CME group had the highest RC/IC (0.24), the lowest mean MD (1.01 g/cm(3) ) and the lowest MIP (2.23). The CE group exhibited a more acceptable CRE (RC/IC = 0.13, mean MD = 1.21 g/cm(3) ) but had a higher MIP (3.95). Both the CRE and MIP parameters of FACE technology were the second most acceptable (RC/IC = 0.12, mean MD = 1.13 g/cm(3) , MIP = 3.20) and did not differ significantly from the most acceptable. FACE is an effective caries removal technology for removing infected dentine without significantly increasing cavity size. © 2013 Australian Dental Association.

  2. Computerized tomography in evaluation of decreased acetabular and femoral anteversion; Besonderheiten bei der Bestimmung der Hueftpfannenanteversion und Schenkelhalsantetorsion durch Computertomographie

    Energy Technology Data Exchange (ETDEWEB)

    Toennis, D.; Skamel, H.J. [Institut fuer Strahlendiagnostik, Klinikum Dortmund GmbH (Germany)

    2003-09-01

    Computerized tomography has received a new importance. It has been shown that decreased anteversion of femur and acetabulum, when both have decreased angles, are causing pain and osteoarthritis of the hip joint. Operative treatment should be performed before osteoarthritis develops. Exact measurements therefore are necessary. The investigation should be performed in prone position to have the pelvis lying in a defined and normal position. Femoral torsion is measured between the transverse axis of the knee and the femoral neck. The transverse axis for measurement of the femoral anteversion is defined by a rectangular line to the sagittal plane. For evaluation of the femoral anteversion in total the angle of the condyles has to be added to the femoral neck angle when the knee is found in internal rotation. Acetabular anteversion should be measured at the level where the femoral head is still in full contact and congruence with the anterior margin of the acetabulum. (orig.) [German] Fuer die Computertomographie hat sich eine neue Aufgabe ergeben. Es hat sich gezeigt, dass verringerte Pfannenanteversion und Schenkelhalsantetorsion haeufige Ursachen von Hueftschmerz und -arthrose sind, v. a. wenn beide gegen 0 gehen. Da operative Massnahmen vor Eintreten der Arthrose ergriffen werden sollten, sind genaue Messwerte erforderlich. Die Untersuchung sollte in Bauchlage durchgefuehrt werden, um eine einheitliche und weitgehend normale Beckenkippung zu gewaehrleisten. Die Schenkelhalstorsion wird zwischen der Kniegelenk- und der Schenkelhalsachse gemessen. Zur Festlegung der Sagittalebene legt man am besten eine Mittellinie zwischen die Beckenschaufeln. Die Messung der Pfannenanteversion sollte in der Schnitthoehe erfolgen, wo die Bewegungseinschraenkung der Innenrotation auftritt. (orig.)

  3. Regional cerebral blood flow in acute stage ischemic cerebrovascular disease by xenon-133 inhalation and single photon emission computerized tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kurokawa, Hiroyuki (Akita Univ. (Japan). School of Medicine)

    1989-03-01

    During the period from February 1984 through June 1985, single photon emission computerized tomography (SPECT) with xenon-133 inhalation method has been performed for the measurement of regional cerebral blood flow (rCBF) during the first 48 hours of onset of cerebral infarction (n=71) and transient ischemic attack (n=21). X-ray CT (CT) and carotid arteriography were concurrently performed in all the patients. In repeated studies performed for 15 normal volunteers, rCBF measurement by SPECT was found reproducible. Mean values of rCBF for the right and left cerebral hemispheres were 60.3{plus minus}6.52 and 61.8{plus minus}6.91 ml/100 g/min, respectively. For cerebral infarction, ischemic foci corresponding to clinical symptoms were detected more frequently on SPECT than on CT (93% vs 63%). In all of the evaluable 35 patients with cerebral infarction, rCBF within the first 8 hours of onset was decreased: 31.0 ml/100 g/min for the internal carotid artery (ICA) occlusion and 36.0 ml/100 g/min for the middle cerebral artery (MCA) occlusion. Crossed cerebellar diaschisis was observed in 50% (9/18) for ICA occlusion and 37% (14/38) for MCA occlusion. For transient ischemic attack, there was no significant difference in the detection of ischemic foci between SPECT and CT (38% vs 43%). In detecting small foci especially in the deep regions such as the basal ganglia, SPECT was inferior to CT. Mean rCBF for transient ischemic attack tended to be lower than the normal rCBF (50.7 ml/100 g/min for the right cerebral hemisphere and 50.6 ml/100 g/min for the left cerebral hemisphere). SPECT may aid in predicting prognosis and chosing treatment strategy, as well as in determining cerebral hemodynamics. (N.K.).

  4. Non-contrast-enhanced computerized tomography and analgesic-related kidney disease: report of the national analgesic nephropathy study.

    Science.gov (United States)

    Henrich, William L; Clark, Richard L; Kelly, Judith P; Buckalew, Vardaman M; Fenves, Andrew; Finn, William F; Shapiro, Joseph I; Kimmel, Paul L; Eggers, Paul; Agodoa, Larry E; Porter, George A; Shapiro, Samuel; Toto, Robert; Anderson, Theresa; Cupples, L Adrienne; Kaufman, David W

    2006-05-01

    Previous studies suggested that the non-contrast-enhanced computerized tomography (CT) scan is a highly reliable tool for the diagnosis of analgesic-associated renal disease. However, this issue has not been addressed in the US population. A total of 221 incident patients with ESRD from different regions of the United States underwent a helical CT scan and detailed questioning about drug history. Specific renal anatomic criteria were developed to determine whether a constellation of CT findings (small indented calcified kidneys [SICK]) is linked to analgesic ingestion. For approximating use before the onset of renal disease, only analgesic ingestion at least 9 yr before starting dialysis was considered relevant. Fifteen patients met the criteria for SICK. This represented 7% of the enrolled patients and approximately 1% of the total ESRD population. There was a significant increase in the estimated risk among patients with a history of heavy aspirin ingestion (odds ratio [OR] 7.4 [95% confidence interval (CI) 1.2 to 43] for > or =1 kg lifetime; OR 8.8 [95% CI 1.2 to 66] for > or =0.3 kg/yr). Total analgesic ingestion of > or =0.3 kg/yr also was significantly associated with SICK (OR 8.2; 95% CI 1.5 to 45). These findings were accounted for largely by combination products that contained aspirin and phenacetin (used by three patients with SICK), which are no longer available. In addition, the CT finding of SICK was present only in a minority of heavy analgesic users, yielding a sensitivity of 5 to 26%. Findings of SICK are infrequent in the US ESRD population and do not occur among a sufficient proportion of heavy analgesic users to render the non-contrast-enhanced CT scan a sensitive tool to detect analgesic-associated kidney injury.

  5. The development of an x-ray computerized tomography (CT) experimental system

    Energy Technology Data Exchange (ETDEWEB)

    Lee, G.N.; Kijek, M.M.; Millar, J.J. [Royal Melbourne Inst. of Tech., VIC (Australia)

    1993-12-31

    This paper describes a prototype experimental CT system that has been recently developed at Applied Physics, RMIT/ Physics, La Trobe UCNV. The system incorporates the scanning mode of the first generation CAT-scanner and is designed to perform the scanning of small objects. A microcomputer is used to control the scanning motions and data collection. The performance of the system was examined by scanning a ball-point pen. 8 refs., 4 figs.

  6. Prostate cancer and abdomino-pelvic masses with {sup 99m}Tc-HDP uptake. Contribution of the single photon emission computerized tomography guided by computerized tomography (SPECT/CT); Cancer de la prostate et masses abdominopelviennes fixant le {sup 99m}Tc-HDP. Apport de la tomographie d'emission monophotonique couplee a la tomodensitometrie (TEMP-TDM)

    Energy Technology Data Exchange (ETDEWEB)

    Granier, P.; Mourad, M. [Centre Hospitalier Antoine-Gayraud, Service de Medecine Nucleaire, 11 - Carcassonne (France)

    2009-06-15

    We report the case of a 63-year-old man, investigated for staging of a prostatic cancer, diagnosed by biopsy, following a rise in the prostatic specific antigen (P.S.A.) on a systematic assessment. The interrogation before examination revealed signs of beginning right crural neuropathy. The hydroxy-methylene diphosphonate technetium 99 m-labeled ({sup 99m}Tc-H.D.P.) whole-body bone scintigraphy highlighted two extraosseous uptake images, the first of moderated intensity in the right iliac area, the second milder, in the abdominal median area. Osseous metastases were not visualized. The single photon emission computerized tomography guided by computerized tomography (SPECT/CT) identified the median abdominal mass which corresponded to a bulky aneurysm of the under renal abdominal aorta. The right iliac mass could be accurately analyzed and differentiated from the various organs of the abdomino-pelvic cavity. Its lymphatic origin was hypothesized, but the diagnosis of lymphatic metastasis of the prostatic cancer was obtained by the pathologic examination of CT scan-guided biopsy. (authors)

  7. Usefulness of thin axial images of computerized tomography angiography for surgery on paraclinoid carotid artery aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Nagasawa, Shiro; Deguchi, Jun; Arai, Motohiro; Tanaka, Hideo; Ohta, Tomio [Osaka Medical Coll., Takatsuki (Japan)

    1995-08-01

    Ten cases involving a total of 13 aneurysms located in the clinoid portion of the carotid artery were included in this study according to Al-Radham`s classification. Non-ionic, iodinated contrast solution, a total of 2 ml/ kg, was intravenously infused at a rate of 2 ml/sec. Helical scanning was begun 30 seconds after initiating the infusion, 1 mm pitch/1.5 second/rotation. 3-D images and original images of axial slices were compared to conventional angiography, DSA and surgical findings. The 3-D images of 3-D-CT-A were able to demonstrate both aneurysms located in the C2 segment of the carotid artery (groups I and II), and five of nine carotid cave aneurysms (group III). The aneurysms located more proximally (group IV or V) could not be visualized. Original axial images of 3-D-CT-A, on the other hand, clearly demonstrated the C2, C3 and C4 segment of the carotid artery, dome and neck of the aneurysm and bone structures such as the anterior clinoid process (ACP) and sella turcica in all cases. 3-D-CT-A is known to have several advantages in cases involving common locations around the Willis ring: multiple aneurysms on a single approach line, a giant aneurysm whose neck is not clearly demonstrated, or bony structures disturbing the access to aneurysms. However, it has been generally regarded that 3-D-CT-A is of little value for diagnosing paraclinoid internal carotid artery aneurysms. This study demonstrated that a series of original axial images of 3-D-CT-A provides excellent information regarding surgical anatomy; each segment of the carotid artery, neck and dome of the aneurysms, the ACP and its topographic relations to the aneurysm, calcification, and so forth. Since aneurysms can be visualized even in the presence of clips applied to adjacent aneurysms, original images are useful for the follow-up of these specific untreated aneurysms. (J.P.N.).

  8. Real-time computerized tomography(CT) test of failure process of jointed granite under unloading in three gorges project(TGP)

    Institute of Scientific and Technical Information of China (English)

    REN Jian-xi

    2004-01-01

    This paper deals with the real-time computerized tomography(CT) test for monitoring the complete damage failure process of a single-crack granite specimen that is subjected to the confining pressure unloading. For this purpose, the State Key Laboratory of Frozen Soil of China has developed a special CT Triaxial Testing Equipment for Rocks and Soils that can give clear images of complete failure process of a rock specimen during removal of confining pressures, including various stages of development and penetration of cracks etc. The results have shown that it is easy for failure phenomenon to happen suddenly in the process of unloading condition of jointed rocks.

  9. Post transplant urinary tract infection in Autosomal dominant polycystic kidney disease a perpetual diagnostic dilema - 18-fluorodeoxyglucose - Positron emission computerized tomography - A valuable tool.

    Science.gov (United States)

    Sainaresh, Vv; Jain, Sh; Patel, Hv; Shah, Pr; Vanikar, Av; Trivedi, Hl

    2011-04-01

    Urinary tract infection (UTI) is the most common infection contracted by renal allograft recipients. In patients of autosomal dominant polycystic kidney disease (ADPKD), cyst infection presents a complex diagnostic and therapeutic challenge especially in the post transplant period. Accurate diagnosis forms the cornerstone in salvaging the graft from potentially catastrophic outcome. We describe a case of xanthogranulomatous pyelonephritis (XPN) in the native kidney in a patient of post transplant ADPKD which presented as frequently relapsing UTI with graft dysfunction where in accurate diagnosis was made possible with the aid of 18-fluorodeoxyglucose (FDG) - Positron emission computerized tomography (PET/CT).

  10. Investigating the effect of characteristic x-rays in cadmium zinc telluride detectors under breast computerized tomography operating conditions.

    Science.gov (United States)

    Glick, Stephen J; Didier, Clay

    2013-10-14

    A number of research groups have been investigating the use of dedicated breast computerized tomography (CT). Preliminary results have been encouraging, suggesting an improved visualization of masses on breast CT as compared to conventional mammography. Nonetheless, there are many challenges to overcome before breast CT can become a routine clinical reality. One potential improvement over current breast CT prototypes would be the use of photon counting detectors with cadmium zinc telluride (CZT) (or CdTe) semiconductor material. These detectors can operate at room temperature and provide high detection efficiency and the capability of multi-energy imaging; however, one factor in particular that limits image quality is the emission of characteristic x-rays. In this study, the degradative effects of characteristic x-rays are examined when using a CZT detector under breast CT operating conditions. Monte Carlo simulation software was used to evaluate the effect of characteristic x-rays and the detector element size on spatial and spectral resolution for a CZT detector used under breast CT operating conditions. In particular, lower kVp spectra and thinner CZT thicknesses were studied than that typically used with CZT based conventional CT detectors. In addition, the effect of characteristic x-rays on the accuracy of material decomposition in spectral CT imaging was explored. It was observed that when imaging with 50-60 kVp spectra, the x-ray transmission through CZT was very low for all detector thicknesses studied (0.5-3.0 mm), thus retaining dose efficiency. As expected, characteristic x-ray escape from the detector element of x-ray interaction increased with decreasing detector element size, approaching a 50% escape fraction for a 100 μm size detector element. The detector point spread function was observed to have only minor degradation with detector element size greater than 200 μm and lower kV settings. Characteristic x-rays produced increasing distortion

  11. Acute Pyelonephritis Focusing on Perfusion Defects on Contrast Enhansed Computerized Tomography(CT) Scans and Its Clinical Outcome

    Science.gov (United States)

    Ha, Sung-Kyu; Seo, Jung-Kun; Kim, Seung-Jung; Park, Seung-Ho; Park, Chong-Hoon; Lee, Ho-Yung; Han, Dae-Suk; Kim, Ki-Whang

    1997-01-01

    Objectives Many cases of acute pyelonephritis show renal perfusion defects on contrast enhanced computerized tomography (CT) imaging studies. The purpose of this study is to show the frequency of renal perfusion defects in uncomplicated acute pyelonephritis and to compare the clinical responses of patients who had perfusion defects or not. Methods We studied patients who had symptoms and signs of acute pyelonephritis through CT examinations with contrast enhancement. We identified 21 cases who had perfusion defects among 35 patients who had undergone CT imaging studies and compared the clinical data in the two groups of patients who had perfusion defects on CT (group 1) and who had not (group 2). Results Nearly all patients had typical symptoms and signs of acute pyelonephritis such as high fever and chill, flank pain and costovertebral angle tenderness. Combined clinical problems were septic shock (one case, 4.8%) and disseminated intravascular coagulation (DIC) (one case, 4.8%) in group 1. Laboratory findings were not different between the two groups. All patients were treated with antibiotics and had successful recoveries. The duration of recovery of pyuria in group 1 (5.2±9.6 days) was not longer than that in group 2(3.1±2.9 days) (p>0.05). The length of defeverscence in group 1 (7.0±4.6 days) was longer than in group 2 (3.5±2.7 days) (ppyelonephritis patients). We classified CT findings of group 1 as focal unilateral (2 cases, 9.5%), multifocal unilateral (14 cases, 66.7%) and multifocal bilateral (5 cases, 23.8%), and there were no differences between the subgroups of group 1 in the duration of defeverscence. Conclusion Those patients who had perfusion defects on CT showed relatively severe clinical courses but responses to early antibiotics were very good. Contrast enhanced CT scans may be very sensitive for the detection of acute renal parenchymal inflammatory disease and for defining the extent of disease, but it is clinically not essential to perform

  12. The use of computerized tomography in pediatrics: risk of radiation; Actualizacion de temas relacionados con elriesgo de radiacion y la obtencion de imagenes pediatricas por tomografia computerizada

    Energy Technology Data Exchange (ETDEWEB)

    Lane, F.; Donnelly, M. D.

    2004-07-01

    The use of computerized tomography in paediatrics is rapidly increasing and with that the dose received by the patients. Recent publications show that the new technique is overused and therefore the cancer risk is increasing in paediatric patients. The article discusses the strategies in use ro reduce the radiation doses without losing the advantages of the new technique. Paediatric doses can be reduced adjusting the photon beam to the density and dimensions of the paediatric patient, in new equipment modulating automatically the current and the tension in the cathodic tube to the optimum values without impairing the quality of the image. Dose can also be reduce increasing the rotation velocity and the pitch of the gantry, limiting the exploration to the region of interest and using shielding to protect the most sensitive tissues. Nevertheless, the article defends the prudent use of computerised tomography and recommends, whenever possible, the use of complementary non ionizing radiation techniques. (Author) 26 refs.

  13. Proposal for dose measurement in the crystalline lens and thyroid in computerized tomography of paranasal sinuses; Proposta de medicao de dose no cristalino e na tireoide em exame de tomografia de seios da face

    Energy Technology Data Exchange (ETDEWEB)

    Mello, Ana Caroline; Machado Neto, Vicente, E-mail: ana.caroline91@hotmail.com [Universidade Tecnologica Federal do Parana (UTFPR/PPGEB), Curitiba, PR (Brazil). Programa de Pos Graduacao em Engenharia Biomedica

    2014-07-01

    With the evolution of diagnostic imaging equipment, a computerized tomography (CT) has become one of the most used tests to assess pathologies affecting the paranasal sinuses. This work aims at presenting a method of obtaining measurements of dose in the eye lenses and thyroid, from the execution of CT of the paranasal sinuses protocol. Experimental procedure will be used in an object simulator (phantom) head and neck made with accessible materials and thermoluminescent dosimeters (TLDs) of LiF: Mg,Ti for the absorbed dose in the regions of interest, when exposed to radiation in a CT scanner 16 channels. After the dosimetric evaluation with phantom use, this methodology will be applied in vivo, or in patients with medical request for the examination and approval by the Ethics Committee. Thus, at the end of this survey protocols and actions aimed at reducing the absorbed dose in the eye lenses and thyroid without impairing the diagnostic image quality can be proposed. (author)

  14. Preoperative Computerized Tomography and Magnetic Resonance Imaging of the Pancreas Predicts Pancreatic Mass and Functional Outcomes After Total Pancreatectomy and Islet Autotransplant.

    Science.gov (United States)

    Young, Michael C; Theis, Jake R; Hodges, James S; Dunn, Ty B; Pruett, Timothy L; Chinnakotla, Srinath; Walker, Sidney P; Freeman, Martin L; Trikudanathan, Guru; Arain, Mustafa; Robertson, Paul R; Wilhelm, Joshua J; Schwarzenberg, Sarah J; Bland, Barbara; Beilman, Gregory J; Bellin, Melena D

    2016-08-01

    Approximately two thirds of patients will remain on insulin therapy after total pancreatectomy with islet autotransplant (TPIAT) for chronic pancreatitis. We investigated the relationship between measured pancreas volume on computerized tomography or magnetic resonance imaging and features of chronic pancreatitis on imaging, with subsequent islet isolation and diabetes outcomes. Computerized tomography or magnetic resonance imaging was reviewed for pancreas volume (Vitrea software) and presence or absence of calcifications, atrophy, and dilated pancreatic duct in 97 patients undergoing TPIAT. Relationship between these features and (1) islet mass isolated and (2) diabetes status at 1-year post-TPIAT were evaluated. Pancreas volume correlated with islet mass measured as total islet equivalents (r = 0.50, P pancreas volume and 3 imaging features strongly associated with 1-year insulin use (P = 0.07), islet graft failure (P = 0.003), hemoglobin A1c (P = 0.0004), fasting glucose (P = 0.027), and fasting C-peptide level (P = 0.008). Measures of pancreatic parenchymal destruction on imaging, including smaller pancreas volume and calcifications, associate strongly with impaired islet mass and 1-year diabetes outcomes.

  15. Regional cerebral blood flow during rest and skilled hand movements by xenon-133 inhalation and emission computerized tomography

    DEFF Research Database (Denmark)

    Lauritzen, M; Henriksen, L; Lassen, N A

    1981-01-01

    Regional cerebral blood flow (CBF) was studied in 16 normal adult volunteers during rest and in 10 the study was repeated during skilled hand movements. A fast-rotating ("dynamic"), single-photon emission computerized tomograph (ECT) with four detector heads was used. Xenon-133 was inhaled over a 1...

  16. Induced arousal following zolpidem treatment in a vegetative state after brain injury in 7 cases Analysis using visual single photon emission computerized tomography and digitized cerebral state monitor

    Institute of Scientific and Technical Information of China (English)

    Bo Du; Aijun Shan; Di Yang; Wei Xiang

    2008-01-01

    BACKGROUND: Several studies have reported the use of zolpidem for induced arousal after permanent vegetative states. However, changes in brain function and EMG after zolpidem treatment requires further investigation. OBJECTIVE: To investigate the effect of zolpidem, an unconventional drug, on inducing arousal in patients in a permanent vegetative state after brain injury using visual single photon emission computerized tomography and digitized cerebral state monitor. DESIGN: A self-controlled observation. SETTING: Shenzhen People's Hospital.PARTICIPANTS: Seven patients in a permanent vegetative state were selected from the Department of Neurosurgery, Shenzhen People's Hospital from March 2005 to May 2007. The group included 5 males and 2 females, 24–55 years of age, with a mean age of 38.5 years. All seven patients had been in a permanent vegetative statement for at least six months. The patient group included three comatose patients, who had sustained injuries to the cerebral cortex, basal ganglia, or thalamus in motor vehicle accidents, and four patients, who had suffered primary/secondary brain stem injury. Informed consents were obtained from the patients’ relatives. METHODS: The patients brains were imaged by 99Tcm ECD single photon emission computerized tomography prior to treatment with zolpidem [Sanofi Winthrop Industrie, France, code number approved by the State Food & Drug Administration (SFDA) J20040033, specification 10 mg per tablet. At 8:00 p.m., 10 mg zolpidem was dissolved with distilled water and administered through a nasogastric tube at 1 hour before and after treatment and 1 week following treatment, respectively. Visual analysis of cerebral perfusion changes in the injured brain regions before and after treatment was performed. Simultaneously, three monitoring parameters were obtained though a cerebral state monitor, which included cerebral state index, electromyographic index, and burst suppression index. MAIN OUTCOME MEASURES: Comparison

  17. High-resolution nuclear magnetic resonance imaging and single photon emission computerized tomography--cerebral blood flow in a case of pure sensory stroke and mild dementia owing to subcortical arteriosclerotic encephalopathy (Binswanger's disease)

    DEFF Research Database (Denmark)

    De Chiara, S; Lassen, N A; Andersen, A R

    1987-01-01

    involving visiospatial apraxia; this pointed to decreased function of the right parietal cortex, which was structurally intact on CT and NMRI. Single photon emission computerized tomography by Xenon-133 injection and by hexamethyl-propyleneamine-oxim labeled with Technetium-99m showed asymmetric...

  18. X-ray computerized tomography analysis and density estimation using a sediment core from the Challenger Mound area in the Porcupine Seabight, off Western Ireland

    Science.gov (United States)

    Tanaka, Akiko; Nakano, Tsukasa; Ikehara, Ken

    2011-02-01

    X-ray computerized tomography (CT) analysis was used to image a half-round core sample of 50 cm long recovered from near Challenger Mound in the Porcupine Seabight, off western Ireland during the Integrated Ocean Drilling Program Expedition 307. This allowed three-dimensional examination of complex shapes of pebbles and ice-rafted debris in sedimentary sequences. X-ray CT analysis was also used for the determination of physical properties; a comparison between bulk density by the mass-volume method and estimated density based on linear attenuation coefficients of X-ray CT images provides insight into a spatially detailed and precise map of density variation in samples through the distribution of CT numbers.

  19. Epiploic appendicitis and omental infarction. Findings in the ultrasonography and computerized tomography; Apendicitis epiploica e infarto omental. Hallazgos en ecografia y tomografia computarizada

    Energy Technology Data Exchange (ETDEWEB)

    Migule, A.; Ripolles, T.; Martinez, M. J.; Morote, V.; Ruiz, A. [Hospital Universitario Dr. Peset. Valencia (Spain)

    2001-07-01

    Describe the findings in the ultrasonography and computerized tomography (CT) of the omental infarction and epiploic appendicitis. The clinical and radiological findings of the patients diagnosed in our hospital with epiploic appendicitis or omental infarctions between August 1994 and March 2001 were assessed retrospectively. We found a high incidence (42 cases) of these two diseases: 30 patients with diagnosis of epiploic appendicitis and 12 with the diagnosis of omental infarction. Four patients were treated surgically, while the remaining 38 were conservatively, without posterior complications. The ultrasonography and CT images is characteristics. making it possible to make a diagnosis of epiploic appendicitis or omental infarction with certainty. It is not necessary to make a differential diagnosis between the two entities because their prognosis and treatment are similar. Their incidence is much more frequent than that previously published. (Author) 19 refs.

  20. Central nervous system involvement in human immunodeficiency virus disease. A prospective study including neurological examination, computerized tomography, and magnetic resonance imaging

    DEFF Research Database (Denmark)

    Pedersen, C; Thomsen, C; Arlien-Søborg, P;

    1991-01-01

    Sixty-seven patients with different stages of human immunodeficiency virus (HIV) infection (47 CDC group IV, 20 CDC groups II or III) were followed prospectively for a median of 18 months with neurological examination, magnetic resonance imaging (MRI), and computerized tomography (CT) to evaluate...... the incidence of the AIDS dementia complex (CDC definition) and other neurological complications. Ten patients developed CNS opportunistic infection or malignancy. Among the remaining 57 patients, 12 of 37 (32%) belonging to CDC group IV, and 1 of 20 (5%) belonging to CDC groups II/III developed the AIDS...... dementia complex (p = 0.03). MRI white matter lesions occurred in 32% of CDC group IV patients and 5% of CDC groups II/III patients (p = 0.03). The corresponding figures for brain atrophy at CT were 71% and 30% (p less than 0.01) and for neurologic signs 49% and 20% (p = 0.06). The development of the AIDS...

  1. Uncommon Cone-Beam Computerized Tomography Findings in McCune-Albright Syndrome in an Implant Candidate Patient: A Case Report

    Directory of Open Access Journals (Sweden)

    Khoshhal

    2013-06-01

    Full Text Available Introduction McCune-Albright syndrome is a rare disease, characterized by triad of cafe-au-lait spots, endocrinopathies and fibrous dysplasia. These bone lesions are usually revealed during the first decade of life, together with pain, pathological fractures and secondary deformities. Case Presentation A 40-year-old female patient presented an opaque lesion at the left mandibular side of face, in a cone-beam computerized tomography (CBCT view, during the implant placement evaluations. The patient had experienced precocious puberty and had undergone hysterectomy. Unilateral cafe-au-lait spots were present on patient’s left side of the face. There was no expansion in intraoral examination. The oral mucosa was also normal. No asymmetry was detected. The analysis of sample histopathology confirmed fibrous dysplasia. Discussion In this patient we preferred following up. Afterwards, total surgical lesion resection can be performed. After a long-term follow-up, the area may receive an implant.

  2. Evaluation of the normal thoracic and abdominal aorta diameters by computerized tomography; Avaliacao dos diametros normais da aorta toracica e abdominal pela tomografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Lucarelli, Claudio Luiz

    1995-07-01

    The study was undertaken to evaluate, through computerized tomography, the diameters of the normal thoracic and abdominal aorta, as well as they are connected to gender, age and body surface area; and the ratio between measurements obtained at the ascending and descending limbs of the thoracic aorta, and between the abdominal aortic diameters. For that reason, we measured the widest anteroposterior diameters of the thoracic aortas at the levels of the arch, the root, the pulmonary artery, and the thoracic-abdominal transition, as well as the level of the emergence of the superior mesenteric artery, of the renal hila and just cephalad to the bifurcation of the abdominal aortas of 350 patients without cardiovascular diseases who had undergone computerized tomography of the thorax and/or abdomen for any other reasons. Observation and statistic analyses led us to conclude that: 1) both the thoracic and abdominal aortic diameters are reduced from their proximal to their distal portions; 2) the body surface influences the size of the aorta, although only extreme variations alter the vessel's caliber; 3) vessel diameter was observed to gradually increase with age; 4) men were found to have larger diameters than age matched women; 5) the ratio between the ascending and descending aortic diameters varies according to gender and age; 6) the relations between abdominal aortic diameters measured at the level of renal hila and cephalad to the bifurcation are independent from gender and age. But the relation between those measured at the level of the superior mesenteric artery and cephalad to the bifurcation are linked to gender, but not to age. (author)

  3. Micro-radiography and micro-computerized tomography with absorption and phase contrast for materials characterization; Mikro-Radiografie und Mikro-Computertomografie mit Absorptions- und Phasenkontrast fuer die Materialcharakterisierung

    Energy Technology Data Exchange (ETDEWEB)

    Kastner, Johann [FH Oberoesterreich, Wels (Austria)

    2017-08-01

    The contribution describes modern techniques in micro-radiography and micro-computerized tomography for materials characterization using absorption and phase contrast. Using micro- and nano-focus tubes and adequate high.-resolution detectors it is possible to reach resolutions significantly below 1 micron. The CT technology allows in-situ deformation testing to study the damaging mechanism of materials. The application of the Talbot-Lau interferometer with CT a differential phase contrast tomography is available. Dark-field tomography is used to study individual carbon fiber bundles in carbon fiber reinforced laminates.

  4. Full-field optical coherence tomography apply in sphere measurements

    Science.gov (United States)

    Shi, Wei; Li, Weiwei; li, Juncheng; Wang, Jingyu; Wang, Jianguo

    2016-10-01

    The geometry of a spherical surface, for example that of a precision optic, is completely determined by the radius -of-curvature at one point and the deviation from the perfect spherical form at all other points of the sphere. Full-field Optical Coherence Tomography (FF-OCT) is a parallel detection OCT technique that utilizes a 2D detector array. This technique avoids mechanical scanning in imaging optics, thereby speeding up the imaging process and enhancing the quality of images. The current paper presents an FF-OCT instrument that is designed to be used in sphere measurement with the principle of multiple delays (MD) OCT to evaluate the curvature and radius of curved objects in single-shot imaging. The optimum combination of the MD principle with the FF-OCT method was evaluated, and the radius of a metal ball was measured with this method. The generated 2n-1 contour lines were obtained by using an MDE with n delays in a single en-face OCT image. This method of measurement, it engaged in the measurement accuracy of spherical and enriches the means of measurement, to make a spherical scan techniques flexible application.

  5. Determination of the initial energy in computerized tomography with proton beams; Determinacao da energia inicial em tomografia computadorizada com feixe de protons

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Rodrigo Luis da

    2007-07-01

    In earliest works devoted to proton computed tomography it was shown that the advantage of pCT image reconstruction appears when the energy is close to the Bragg peak region, since the proton passes the object. This effect provided by the Bragg peak makes the computerized tomography with protons possible. However, when decreasing the initial proton energy, with the increase of the irradiation dose, there are two effects that work simultaneously in opposite ways. First, the energy loss of a proton in an object becomes bigger at small initial energy. At the same time decreasing of the proton energy results in the increase of the energy straggling, requiring a larger number of protons. In this work the radiation dose dependence on the proton initial energy was studied using analytical formulas and computer simulations. The investigation determined that the radiation dose practically does not depend on the initial energy, except in the energy region very close to the minimum energy necessary to pass the object. (author)

  6. Prognostic value of technetium-99m-labeled single-photon emission computerized tomography in the follow-up of patients after their first myocardial revascularization surgery

    Directory of Open Access Journals (Sweden)

    Márcia Maria Sales dos Santos

    2003-01-01

    Full Text Available OBJECTIVE: To assess the prognostic value of Technetium-99m-labeled single-photon emission computerized tomography (SPECT in the follow-up of patients who had undergone their first myocardial revascularization. METHODS: We carried out a retrospective study of 280 revascularized patients undergoing myocardial scintigraphy under stress (exercise or pharmacological stress with dipyridamole and at rest according to a 2-day protocol. A set of clinical, stress electrocardiographic and scintigraphic variables was assessed. Cardiac events were classified as "major" (death, infarction, unstable angina and "any" (major event or coronary angioplasty or new myocardial revascularization surgery. RESULTS: Thirty-six major events occurred as follows: 3 deaths, 11 infarctions, and 22 unstable anginas. In regard to any event, 22 angioplasties and 7 new surgeries occurred in addition to major events, resulting a total of 65 events. The sensitivity of scintigraphy in prognosticating a major event or any event was, respectively, 55% and 58%, showing a negative predictive value of 90% and 83%, respectively. Diabetes mellitus, inconclusive stress electrocardiography, and a scintigraphic visualization of left ventricular enlargement were significant variables for the occurrence of a major event. On multivariate analysis, abnormal myocardial scintigraphy was a predictor of any event. CONCLUSION: Myocardial perfusion tomography with Technetium-99m may be used to identify high-risk patients after their first myocardial revascularization surgery.

  7. X-Ray Micro-Tomography Applied to Nasa's Materials Research: Heat Shields, Parachutes and Asteroids

    Science.gov (United States)

    Panerai, Francesco; Borner, Arnaud; Ferguson, Joseph C.; Mansour, Nagi N.; Stern, Eric C.; Barnard, Harold S.; Macdowell, Alastair A.; Parkinson, Dilworth Y.

    2017-01-01

    X-ray micro-tomography is used to support the research on materials carried out at NASA Ames Research Center. The technique is applied to a variety of applications, including the ability to characterize heat shield materials for planetary entry, to study the Earth- impacting asteroids, and to improve broadcloths of spacecraft parachutes. From micro-tomography images, relevant morphological and transport properties are determined and validated against experimental data.

  8. Cone-beam computerized tomography imaging and analysis of the upper airway: a systematic review of the literature.

    NARCIS (Netherlands)

    Guijarro-Martinez, R.; Swennen, G.R.J.

    2011-01-01

    A systematic review of the literature concerning upper airway imaging and analysis using cone-beam computed tomography (CBCT) was performed. A PubMed search (National Library of Medicine, NCBI; revised 9th January 2011) yielded 382 papers published between 1968 and 2010. The 382 full papers were scr

  9. The usefulness of ultrasound colour-Doppler twinkling artefact for detecting urolithiasis compared with low dose nonenhanced computerized tomography

    DEFF Research Database (Denmark)

    Winkel, Rikke Rass; Kalhauge, Anna; Fredfeldt, Knud-Erik

    2012-01-01

    This prospective study evaluates the usefulness of the twinkling artefact (TA) seen on colour-Doppler ultrasound (US) in diagnosing urolithiasis. US and standard computed tomography (CT) were performed blinded on 105 patients. B-mode US and colour-Doppler used separately and in combination showed...

  10. 电磁波层析成像反演射线路径的探讨%Discussion on Inversion Ray Path of Electro-magnetic Computerized Tomography

    Institute of Scientific and Technical Information of China (English)

    刘海涛; 董艳平; 彭军; 董亮

    2015-01-01

    In computerized tomography test,the position of recording point after data inversion is determined by the position of transmitting point and receiving point between the two probes.In order to find out the position of record-ing points,we carried out experiment on electro-magnetic probe shielding by steel pipes.The experiment show that the energy concentration area between the two probes is parallelogram,hence it is more reasonable to inverse paral-lelogram area with four electro-magnetic wave rays rather than one ray path.On this basis,we propose to obtain the four single inversion result from each ray path and average them as the final result.This method was applied to the data processing of karst exploration for Wuhan underground.Through comparison of inversion result,this method is verified to be more precise than single-path inversion in the environment of the same inversion software.%在电磁波 CT 测试中,发射、接收探头间的电磁波射线发射点、接收点位置决定反演后成果数据记录点的位置。为了确定电磁波仪发射、接收探头记录点位置,对探头分别进行钢管屏蔽实验,实验表明电磁波仪工作时电磁波能量主要集中在两探头的馈电点及天线末端间近似于平行四边形的区域内,不宜直接地简化为一条直线,将平行四边形区域简化为4条线段进行电磁波层析成像反演计算更符合实际情况。在此基础上,提出对电磁波 CT 数据采取4条射线路径单独反演后,再将4个结果按综合平均的方法进行处理。将此种处理方法应用于武汉地铁岩溶勘察数据处理中,并与目前基于1条射线的反演处理方法进行对比、验证。对比剖面反演数据结果表明,在采用同一反演软件条件下4条射线路径综合反演法精度优于1条射线反演法。

  11. DIAPHANE: muon tomography applied to volcanoes, civil engineering, archaelogy

    Science.gov (United States)

    Marteau, J.; de Bremond d'Ars, J.; Gibert, D.; Jourde, K.; Ianigro, J.-C.; Carlus, B.

    2017-02-01

    Muography techniques applied to geological structures greatly improved in the past ten years. Recent applications demonstrate the interest of the method not only to perform structural imaging but also to monitor the dynamics of inner movements like magma ascent inside volcanoes or density variations in hydrothermal systems. Muography time-resolution has been studied thanks to dedicated experiments, e.g. in a water tower tank. This paper presents the activities of the DIAPHANE collaboration between particle- and geo-physicists and the most recent results obtained in the field of volcanology, with a focus on the main target, the Soufrière of Guadeloupe active volcano. Special emphasis is given on the monitoring of the dome's inner volumes opacity variations, that could be ascribed to the hydrothermal system dynamics (vaporization of inner liquid water in coincidence with the appearance of new fumaroles at the summit). I also briefly present results obtained in the fields of civil engineering (study of urban underground tunnels) and archaelogy (greek tumulus scanning).

  12. Low dose four-dimensional computerized tomography with volume rendering reconstruction for primary hyperparathyroidism: How I do it?

    Institute of Scientific and Technical Information of China (English)

    Timothy; A; Platz; Moshim; Kukar; Rania; Elmarzouky; William; Cance; Ahmed; Abdelhalim

    2014-01-01

    Abstract Modification of 4-dimensional computed tomography(4D-CT)technique with volume rendering reconstruc-tions and significant dose reduction is a safe and ac-curate method of pre-operative localization for primary hyperparathyroidism.Modified low dose 4D-CT with volume rendering reconstructions provides precise preoperative localization and is associated with a sig-nificant reduction in radiation exposure compared to classic preoperative localizing techniques.It should be considered the preoperative localization study of choice for primary hyperparathyroidism.

  13. Rupture of Ovarian Mature Cystic Teratoma: Computerized Tomography Findings; Rotura de teratoma quistico madure de ovario: hallazgos por tomografia computerizada

    Energy Technology Data Exchange (ETDEWEB)

    Sebastia, C.; Sarrias, M.; Sanchez-Aliaga, E.; Quiroga, S.; Boye, R.; Alvarez-Castells, A. [Hospital General Universitari Vall d' Hebron. Barcelona (Spain)

    2004-07-01

    We present computed tomography findings of three cases of intraperitoneal rupture of ovarian mature cystic teratoma. Acute-phase radiological findings include presence of intraabdominal liquid, infiltration of mesenteric fat and calcified pelvic mass which also showed interior fatty content. Chronic-phase findings include infiltration of peritoneal fat, as well as increase in the size of adjacent ganglion due to chronic inflammatory response to histologically verified foreign bodies. Differential diagnoses between chronic and acute intraperitoneal ruptures of mature teratoma have been reviewed. (Author)

  14. Comparison of ventilation/perfusion scintigraphy and multi-detector computerized tomography in diagnosis of asymptomatic pulmonary embolism after deep vein thrombosis

    Directory of Open Access Journals (Sweden)

    Eflatun Yücedağ

    2014-03-01

    Full Text Available Objective: Pulmonary thromboembolism (PTE named due to migration of clots formed in systemic venous system to pulmonary vascular bed is a serious clinical table. After acute DVT, asymptomatic PTE is seen about 40-60% and this situation can not be discovered because of silent clinical course. In this study, we aimed to compare sensivity and spesifity of multi detector computerized tomography (MDCT, which is used extensively in recent years, with ventilation-perfusion (V/P scintigraphy which is used formerly for diagnosis of asymptomatic PTE developed after acute lower extremity DVT. Methods: The study was carried out 25 patients who were admitted to our clinic and treated for lower extremity acute DVT. Pregnants, and cases with recurrent DVT, presence of symptomatic PTE during admission, thrombosis extending to vena cava, and history of passed PTE were excluded from the study. DVTs in patients were diagnosed by color doppler, and confirmed by D-dimer test. After patients’s admission, V/P scintigraphy and MDCT were used to detects asymptomatic PTE at 1st and 8 th day of the admission. Results: D-dimer was measured as higher in 24 of 25 patients with asemptomatic PTE. Ten patients were diagnosed by MDCT. Development of asymptomatic PTE related to acute DVT was determined as 40%. Conclusion: In terms of diagnostic value, MDCT was found more useful than V/P scintigraphy.

  15. Horizontal Bone Augmentation Using Autogenous Block Grafts and Particulate Xenograft in the Severe Atrophic Maxillary Anterior Ridges: A Cone-Beam Computerized Tomography Case Series.

    Science.gov (United States)

    Monje, Alberto; Monje, Florencio; Hernández-Alfaro, Federico; Gonzalez-García, Raúl; Suárez-López del Amo, Fernando; Galindo-Moreno, Pablo; Montanero-Fernández, Jesús; Wang, Hom-Lay

    2015-07-01

    The aim of the present study was to use cone-beam computerized tomography (CBCT) to assess horizontal bone augmentation using block grafts, harvested from either the iliac crest (IC) or mandibular ramus (MR) combined with particulate xenograft and a collagen membrane for in the severe maxillary anterior ridge defects (cases Class III-IV according to Cadwood and Howell's classification). Fourteen healthy partially edentulous patients requiring extensive horizontal bone reconstruction in the anterior maxilla were selected for the study. Nineteen onlay block grafts (from IC or MR) were placed. The amount of horizontal bone gain was recorded by CBCT at 3 levels (5, 7, and 11 mm from the residual ridge) and at the time of bone grafting as well as the time of implant placement (≈5 months). Both block donor sites provided enough ridge width for proper implant placement. Nonetheless, IC had significantly greater ridge width gain than MR (Student t test) (4.93 mm vs 3.23 mm). This was further confirmed by nonparametric Mann-Whitney test (P = .007). Moreover, mean pristine ridge and grafted ridge values showed a direct association (Spearman coefficient of correlation = .336). A combination of block graft, obtained from the IC or MR, combined with particulate xenograft then covered with an absorbable collagen membrane is a predictable technique for augmenting anterior maxillary horizontal ridge deficiency.

  16. Accuracy of a newly developed cone-beam computerized tomography-aided surgical guidance system for dental implant placement: an ex vivo study.

    Science.gov (United States)

    Murat, Sema; Kamburoğlu, Kivanç; Özen, Tuncer

    2012-12-01

    The aim of the present study was to measure the accuracy of the cone-beam computerized tomography (CBCT)- aided StentCad Beyond surgical guidance system and to compare bone-supported and tooth/bone-supported guidance by using this system in dental implant placement ex vivo. Five cadaver mandibles were scanned using an Iluma CBCT scanner. After scanning, DICOM slices were transferred to the StentCad Beyond implant simulation software, which was used for preoperative implant planning. Using the StentCad Beyond guidance system, 9 implant drills were inserted using a bone-supported guidance system and 11 using a tooth/bone-supported guidance system. Mandibles were scanned again and these data were transferred to the StentCad Beyond software. Pre- and postoperative information was superimposed using the Rhinoceros version 4 software program, and deviations between planned and actual drill positions were calculated for each implant. In addition, differences between bone-supported and tooth/bone-supported guidance systems were analyzed by t-test, with a significance level of P .05); however, statistically significant differences between groups were found in mean horizontal coronal deviation (P = .016) and mean horizontal apical deviation (P = .047). The StentCad Beyond system was found to be a reliable guide for placing implants ex vivo.

  17. Experimental study of mechanisms of sand production using X-ray computerized tomography; Estudo experimental dos mecanismos da producao de areia empregando tomografia computadorizada de raios X

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Janaina B.; Vargas Junior, Euripedes [Pontificia Univ. Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil). Dept. de Engenharia Civil; Barroso, Emilio V. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Dept. de Geologia; Campos, Elisabete; Goncalves, Clemente; Tavares, Andre [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2004-07-01

    During productive phase of the well, many times there is simultaneous production of the solid particles detached from matrix of the reservoir rock. This phenomenon receives the name of the sand production. In this case stress and flow conditions around of the well are fundamental factors for deflagration of the process. Stress concentration in the wall of the well lead to the loss of cohesion between grains arising, consequently, a granular material region susceptible for dragging by seepage forces derived from fluid flow. The objective of this work was to perform sand production tests in Rio Bonito and synthetic sandstone samples using real-time X-Ray Computerized Tomography. The tests investigated the initial and the evolution of failure at the cavity wall of samples. These are initial stages of the sand production process. The analysis of the CT-scans obtained during tests allowed the visualization of breakouts and collapses of the wells. From studies more details were possible estimate the sand production and produce 3-D images of the propagation of the failure. (author)

  18. Sensitivity of computer assisted radionuclide angiography in transient ischemic attack and prolonged reversible ischemic neurological deficit. Comparison with findings in radiographic angiography and transmission computerized axial tomography

    Energy Technology Data Exchange (ETDEWEB)

    Buell, U.; Scheid, K.F.; Lanksch, W.; Kleinhans, E.; Ulbert, V.; Reger, U.; Rath, M.; Moser, E.A.

    Computer assisted radionuclide angiography (CARNA) with 99mTc-DTPA was employed to study 143 patients with transient ischemic attacks (TIA) and 79 patients with prolonged reversible ischemic neurologic deficit (PRIND). The results of CARNA were compared with findings from radiographic angiography (RGA) in 173 patients and with findings in transmission computerized axial tomography (T-CAT) in 154 patients. In patients with TIA, CARNA showed a hemispherical perfusion deficit in 74.8%, and with PRIND 87.3%. This deficit, determined as the relative difference between the involved and the non-involved hemisphere, was significantly (p less than 0.0025) greater in PRIND (minus 23%) than in TIA (minus 17%). Sensitivity of CARNA was independent of the interval from ictus to examination for more than 4 months. RGA in TIA revealed true positives in 82.0%, in PRIND it was 89.5%. T-CAT was positive in TIA in only 16.8% but in PRIND it was 64.4%. Combined sensitivities in TIA (92.4%) and in PRIND (94.0%) were highest with the combination of CARNA and RGA. However, in PRIND the combination of non-invasive methods (CARNA and T-CAT) revealed 93.2% positive findings. Combinations of these evaluation methods may be used to detect cerebrovascular disease in patients with such dysfunction.

  19. Comparison of high-resolution peripheral quantitative computerized tomography with dual-energy X-ray absorptiometry for measuring bone mineral density.

    Science.gov (United States)

    Colt, E; Akram, M; Pi Sunyer, F X

    2017-06-01

    The objective of this study was to compare the measurement of areal bone mineral density (aBMD) by dual-energy X-ray absorptiometry (DXA) with the measurement of volumetric bone mineral density (vBMD) by high-resolution peripheral computerized tomography (HR-pQCT) in subjects with a wide range of body mass indices (BMI). We scanned the arms and legs of 49 premenopausal women, aged 21-45 years, with BMI from 18.5 to 46.5, by HR-pQCT and found that there was a nonsignificant change in vBMD associated with increased BMI, whereas aBMD (DXA) was associated with a positive significant increase. HR-pQCT scans a slice at the extremity of the tibia and radius, whereas DXA scans the entire leg and arm. The correlation coefficients (r) of BMD (DXA) of the legs with BMI were 0.552, PD100) of legs and arms measured by HR-pQCT with BMI, W and %fat were not significant. Although HR-pQCT and DXA scan different parts of the bone, the high r of BMD with BMI and low r of bone density measured by HR-pQCT with BMI suggest that BMD measured by DXA is artifactually increased in the presence of obesity.

  20. The role of computerized tomography in the evaluation of gastrointestinal bleeding following negative or failed endoscopy: a review of current status.

    Science.gov (United States)

    Stunell, H; Buckley, O; Lyburn, I D; McGann, G; Farrell, M; Torreggiani, W C

    2008-01-01

    Gastrointestinal bleeding remains an important cause for emergency hospital admission with a significant related morbidity and mortality. Bleeding may relate to the upper or lower gastrointestinal tracts and clinical history and examination may guide investigations to the more likely source of bleeding. The now widespread availability of endoscopic equipment has made a huge impact on the rapid identification of the bleeding source. However, there remains a large group of patients with negative or failed endoscopy, in whom additional techniques are required to identify the source of bleeding. In the past, catheter angiography and radionuclide red cell labeling techniques were the preferred 'next step' modalities used to aid in identifying a bleeding source within the gastrointestinal tract. However, these techniques are time-consuming and of limited sensitivity and specificity. In addition, catheter angiography is a relatively invasive procedure. In recent years, computerized tomography (CT) has undergone major technological advances in its speed, resolution, multiplanar techniques and angiographic abilities. It has allowed excellent visualization of the both the small and large bowel allowing precise anatomical visualization of many causes of gastrointestinal tract (GIT) bleeding. In addition, recent advances in multiphasic imaging now allow direct visualization of bleeding into the bowel. In many centers CT has therefore become the 'next step' technique in identifying a bleeding source within the GIT following negative or failed endoscopy in the acute setting. In this review article, we review the current literature and discuss the current status of CT as a modality in investigating the patient with GIT bleeding.

  1. Computerized ionosphere tomography and numerical simulation%电离层层析成像及数值模拟

    Institute of Scientific and Technical Information of China (English)

    牛俊; 方涵先

    2012-01-01

    In this article, numerical simulation of computerized ionosphere to- mography (CIT) is presented. The result shows that, by using the regularization algorithm, the electron distribution of the ionosphere can be inverted well. The reason which affects the accuracy of the reconstruction is also discussed. A para- ment is defined which represents the accuracy of the reconstruction. By discussing the relation between the parament and the number of signals, it is concluded that the lack of information is the main high precision reconstruction result experiment proves that the CIT can electron distribution. reason for the error. In a good condition, a can be obtained. The numerical simulation be widely used in the inversion of ionosphere%利用正则化反演法,对电离层层析成像技术进行了数值模拟.模拟结果表明,正则化反演法能够准确反演出电离层赤道异常的电子密度分布.对正则化反演误差的原因进行了分析,定义了代表重建结果精度的参数并研究其随信号数量的变化,结果显示造成反演误差的主要原因是信息量不足,在提供充足的数据条件下,正则化反演法能够得到很高精度的重建结果.数值模拟实验进一步证明了电离层层析技术在反演电离层电子密度分布中有很大的应用价值.

  2. Clinical different diagnosis value in complex heart disease between 320-slice computerized tomography and heart echocardiography%320排CT与心脏彩超诊断复杂性心脏病的临床价值差异

    Institute of Scientific and Technical Information of China (English)

    郗二平; 朱健; 朱水波; 殷桂林; 张瑜; 晏明

    2015-01-01

    Objective To investigate clinical diagnosis value in complex heart disease of 320-slice computerized tomography.Methods Twenty-seven patients' imaging data of 320-slice computerized tomography and transthoracic heart echocardiography were taken retrospective analysis,all patients were diagnosed with complex heart disease on cardiothoracic surgery.And the authors compared the diagnostic accuracy of imaging diagnosis and operation diagnosis.Results The diagnostic of 27 patients with 89 cardiac anomalies with 320-slice computerized tomography and were diagnosed 83 cardiac anomalies with transthoracic heart echocardiography.However,92 cardiac anomalies were found on cardiothoracic surgery.The diagnostic accuracy of 27 patients had a statistical difference between 320-slice computerized tomography and transthoracic heart echocardiography with complex heart deformity disease (P < 0.05).Conclusions Compared with transthoracic heart echocardiography,320-slice computerized tomography improved the diagnosis accuracy of the complex heart deformity disease.%目的 探讨320排CT诊断复杂性心脏病的临床价值.方法 回顾分析27例复杂心脏病患者且经心脏手术确诊的320CT和经胸心脏彩超影像学资料,利用手术中的诊断比较两种诊断结果的准确率.结果 27例患者经心脏彩超提示心脏畸形83处,经320排CT检查提示心脏畸形89处,但手术证实发现心脏畸形92处.统计学分析320排CT诊断复杂性心脏病的准确性与心脏彩超相比有统计学意义(P<0.05).结论 与心脏彩超相比,320排CT提高了复杂性心脏病诊断的准确性.

  3. The usefulness of ultrasound colour-Doppler twinkling artefact for detecting urolithiasis compared with low dose nonenhanced computerized tomography.

    Science.gov (United States)

    Winkel, Rikke Rass; Kalhauge, Anna; Fredfeldt, Knud-Erik

    2012-07-01

    This prospective study evaluates the usefulness of the twinkling artefact (TA) seen on colour-Doppler ultrasound (US) in diagnosing urolithiasis. US and standard computed tomography (CT) were performed blinded on 105 patients. B-mode US and colour-Doppler used separately and in combination showed 55% sensitivity and 99% specificity (positive predictive value [PPV] 67% and negative predictive value [NPV] 98%). Of CT verified stones, 61% were ≤3 mm. TAs were present in 74% of the B-mode stones (43% of all CT verified stones). Patients with CT verified stone disease had significantly more TAs in other foci than the stone(s) found on CT, suggestive of microlithiasis. In conclusion, colour-Doppler TA is a helpful supplement for detecting urolithiasis when CT is contraindicated. In addition, US can be valuable in monitoring stones left to pass without intervention if they have presented a TA. CT, US and US with colour-Doppler TA can be useful as complementary techniques for detecting stones.

  4. Analysis of the of bones through 3D computerized tomography; Analise de estrutura ossea atraves de microtomografia computadorizada 3D

    Energy Technology Data Exchange (ETDEWEB)

    Lima, I.; Lopes, R.T. [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE), Rio de Janeiro, RJ (Brazil). Lab. de Instrumentacao Nuclear; Oliveira, L.F. [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Inst. de Fisica. Dept. de Fisica Aplicada e Termodinamica; Alves, J.M. [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Escola de Engenharia

    2009-03-15

    This work shows the analysis of the internal structure of the bones samples through 3D micro tomography technique (3D-{mu}TC). The comprehension of the bone structure is particularly important when related to osteoporosis diagnosis because this implies in a deterioration of the trabecular bone architecture, which increases the fragility and the possibility to have bone fractures. Two bone samples (human calcaneous and Wistar rat femur) were used, and the method was a radiographic system in real time with an X Ray microfocus tube. The quantifications parameters are based on stereological principles and they are five: a bone volume fraction, trabecular number, the ratio between surface and bone volume, the trabecular thickness and the trabecular separation. The quantifications were done with a program developed especially for this purpose in Nuclear Instrumentation Laboratory - COPPE/UFRJ. This program uses as input the 3D reconstructions images and generates a table with the quantifications. The results of the human calcaneous quantifications are presented in tables 1 and 2, and the 3D reconstructions are illustrated in Figure 5. The Figure 6 illustrate the 2D reconstructed image and the Figure 7 the 3D visualization respectively of the Wistar femur sample. The obtained results show that the 3D-{mu}TC is a powerful technique that can be used to analyze bone microstructures. (author)

  5. Neutron tomography of particulate filters: a non-destructive investigation tool for applied and industrial research

    Energy Technology Data Exchange (ETDEWEB)

    Toops, Todd J., E-mail: toopstj@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Bilheux, Hassina Z.; Voisin, Sophie [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Gregor, Jens [University of Tennessee, Knoxville, TN (United States); Walker, Lakeisha; Strzelec, Andrea; Finney, Charles E.A.; Pihl, Josh A. [Oak Ridge National Laboratory, Oak Ridge, TN (United States)

    2013-11-21

    This research describes the development and implementation of high-fidelity neutron imaging and the associated analysis of the images. This advanced capability allows the non-destructive, non-invasive imaging of particulate filters (PFs) and how the deposition of particulate and catalytic washcoat occurs within the filter. The majority of the efforts described here were performed at the High Flux Isotope Reactor (HFIR) CG-1D neutron imaging beamline at Oak Ridge National Laboratory; the current spatial resolution is approximately 50 μm. The sample holder is equipped with a high-precision rotation stage that allows 3D imaging (i.e., computed tomography) of the sample when combined with computerized reconstruction tools. What enables the neutron-based image is the ability of some elements to absorb or scatter neutrons where other elements allow the neutron to pass through them with negligible interaction. Of particular interest in this study is the scattering of neutrons by hydrogen-containing molecules, such as hydrocarbons (HCs) and/or water, which are adsorbed to the surface of soot, ash and catalytic washcoat. Even so, the interactions with this adsorbed water/HC is low and computational techniques were required to enhance the contrast, primarily a modified simultaneous iterative reconstruction technique (SIRT). This effort describes the following systems: particulate randomly distributed in a PF, ash deposition in PFs, a catalyzed washcoat layer in a PF, and three particulate loadings in a SiC PF.

  6. A comparative evaluation on the cleaning and shaping ability of three nickel titanium rotary instruments using computerized tomography - An ex vivo study

    Directory of Open Access Journals (Sweden)

    Gopal S Narayan

    2012-01-01

    Full Text Available Introduction : Successful root canal treatment depends primarily on the removal of micro-organisms through chemo-mechanical instrumentation of the root canal system. This encompasses shaping by mechanical removal of the dentine and cleaning by chemical disinfection of microorganisms and dissolution of organic tissues from the root canal. While root canal shaping can be predictably and efficiently attained with advanced instrumentation technology, effective cleaning of the entire root canal system remains a challenge. Rotary nickel titanium instruments are known for their efficient preparation of root canal. This is mainly because of the super elasticity of the nickel titanium alloy which gives an increased flexibility and allows the instrument to efficiently follow the original path of root canal. The purpose of this study is to compare the cleaning efficiency and shaping ability of M two, K3, Race ni-ti rotary instruments during the preparation of curved canals in extracted molars. Materials and Methods : Thirty teeth with 18 mm as their working length were selected and divided into three groups of 10 teeth each Angle of curvature, Radius of curvature, was determined using computerized tomography. A Pre and Post-operative measurement of canal width and volume was recorded and compared using CT. The teeth was then sectioned into two halves and subjected to scanning electron microscope. Images were taken at the level of apical third, middle third and coronal third for debris and smear layer. Scoring was done separately for both debris and smear layer. Results : Results were tabulated and statistically analyzed to evaluate the shaping ability and cleaning efficiency. Instruments were examined for any deformation or fracture during canal preparation. Conclusion : M two showed greater enlargements in all the three levels, when compared its width and volume, with other two instruments. K3 was better than Race when compared among them. In the scanning

  7. Value of Computerized Tomography Enterography in Predicting Crohn’s Disease Activity: Correlation with Crohn’s Disease Activity Index and C-Reactive Protein

    Science.gov (United States)

    Park, Eun Kyung; Han, Na Yeon; Park, Beom Jin; Sung, Deuk Jae; Cho, Sung Beom; Jeen, Yoon Tae; Keum, Bora; Kim, Min Ju

    2016-01-01

    Background The accurate evaluation of Crohn’s disease activity is important for the treatment of the disease and for monitoring the response. Computerized tomography (CT) enterography is a useful imaging modality that reflects enteric inflammation, as well as extramural complications. Objectives The aim of this study was to evaluate the correlation between CT enterographic (CTE) findings of active Crohn’s disease and the Crohn’s disease activity index (CDAI) and C-reactive protein (CRP). Patients and Methods Fifty CT enterographies of 39 patients with Crohn’s disease in the small bowel were used in our study. The CDAI was assessed through clinical and laboratory variables. Multiple CT parameters, including mural hyperenhancement, mural thickness, mural stratification, comb sign, and mesenteric fat attenuation, were evaluated with a four-point scale. The presence or absence of enhanced lymph nodes, fibrofatty proliferation, sinus or fistula, abscess, and stricture were also assessed. Two gastrointestinal radiologists independently reviewed all CT images, and inter-observer agreement was examined. Correlations between CT findings, CRP, and CDAI were assessed using Spearman’s rank correlation and logistic regression analysis. To assess the predictive accuracy of the model, a receiver-operating characteristic curve analysis for the sum of CT enterographic scores was used. Results Mural hyperenhancement, mural thickness, comb sign, mesenteric fat density, and fibrofatty proliferation were significantly correlated with CDAI and CRP (P < 0.05). The binary logistic regression model demonstrated that mesenteric fat density, mural stratification, and the presence of enhanced lymph nodes (P < 0.05) had an influence on CDAI severity. The area under the receiver operating characteristic curve (AUROC) of the CTE index for predicting disease activity was 0.85. Using a cut-off value of 8, the sensitivity and negative predictive values were 95% and 94%, respectively

  8. The role of computerized tomography in the evaluation of gastrointestinal bleeding following negative or failed endoscopy: A review of current status

    Directory of Open Access Journals (Sweden)

    Stunell H

    2008-01-01

    Full Text Available Gastrointestinal bleeding remains an important cause for emergency hospital admission with a significant related morbidity and mortality. Bleeding may relate to the upper or lower gastrointestinal tracts and clinical history and examination may guide investigations to the more likely source of bleeding. The now widespread availability of endoscopic equipment has made a huge impact on the rapid identification of the bleeding source. However, there remains a large group of patients with negative or failed endoscopy, in whom additional techniques are required to identify the source of bleeding. In the past, catheter angiography and radionuclide red cell labeling techniques were the preferred ′next step′ modalities used to aid in identifying a bleeding source within the gastrointestinal tract. However, these techniques are time-consuming and of limited sensitivity and specificity. In addition, catheter angiography is a relatively invasive procedure. In recent years, computerized tomography (CT has undergone major technological advances in its speed, resolution, multiplanar techniques and angiographic abilities. It has allowed excellent visualization of the both the small and large bowel allowing precise anatomical visualization of many causes of gastrointestinal tract (GIT bleeding. In addition, recent advances in multiphasic imaging now allow direct visualization of bleeding into the bowel. In many centers CT has therefore become the ′next step′ technique in identifying a bleeding source within the GIT following negative or failed endoscopy in the acute setting. In this review article, we review the current literature and discuss the current status of CT as a modality in investigating the patient with GIT bleeding.

  9. Computerized tomography with X-rays: an instrument in the analysis physico-chemical between formations and drilling fluids interactions; Tomografia computadorizada com raios-X: uma ferramenta na analise das interacoes fisico-quimicas entre as formacoes rochosas e fluidos de perfuracao

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, Marcus Vinicius Cavalcante

    1998-12-31

    In this study it is demonstrated the applicability of the Computerized Tomography technique with x-rays to evaluate the reactivity degree between various drilling fluids and argillaceous sediments (Shales and Sandstones). The research has been conducted in the Rock-Fluid Interaction Pressure Simulator (RFIPS), where the possible physico-chemical alterations can be observed through successive tomography images, which are obtained during the flow of the fluid through the samples. In addition, it was noticed the formation of mud cake in Berea Sandstones samples in the RFIPS, though the Computerized Tomography with X-rays, when utilizing drilling fluids weighted with the baryte. (author) 35 refs., 38 figs., 5 tabs.

  10. Dynamic motion analysis of dart throwers motion visualized through computerized tomography and calculation of the axis of rotation.

    Science.gov (United States)

    Edirisinghe, Y; Troupis, J M; Patel, M; Smith, J; Crossett, M

    2014-05-01

    We used a dynamic three-dimensional (3D) mapping method to model the wrist in dynamic unrestricted dart throwers motion in three men and four women. With the aid of precision landmark identification, a 3D coordinate system was applied to the distal radius and the movement of the carpus was described. Subsequently, with dynamic 3D reconstructions and freedom to position the camera viewpoint anywhere in space, we observed the motion pathways of all carpal bones in dart throwers motion and calculated its axis of rotation. This was calculated to lie in 27° of anteversion from the coronal plane and 44° of varus angulation relative to the transverse plane. This technique is a safe and a feasible carpal imaging method to gain key information for decision making in future hand surgical and rehabilitative practices.

  11. Filter assessment applied to analytical reconstruction for industrial third-generation tomography

    Energy Technology Data Exchange (ETDEWEB)

    Velo, Alexandre F.; Martins, Joao F.T.; Oliveira, Adriano S.; Carvalho, Diego V.S.; Faria, Fernando S.; Hamada, Margarida M.; Mesquita, Carlos H., E-mail: afvelo@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Multiphase systems are structures that contain a mixture of solids, liquids and gases inside a chemical reactor or pipes in a dynamic process. These systems are found in chemical, food, pharmaceutical and petrochemical industries. The gamma ray computed tomography (CT) system has been applied to visualize the distribution of multiphase systems without interrupting production. CT systems have been used to improve design, operation and troubleshooting of industrial processes. Computer tomography for multiphase processes is being developed at several laboratories. It is well known that scanning systems demand high processing time, limited set of data projections and views to obtain an image. Because of it, the image quality is dependent on the number of projection, number of detectors, acquisition time and reconstruction time. A phantom containing air, iron and aluminum was used on the third generation industrial tomography with 662 keV ({sup 137}Cs) radioactive source. It was applied the Filtered Back Projection algorithm to reconstruct the images. An efficient tomography is dependent of the image quality, thus the objective of this research was to apply different types of filters on the analytical algorithm and compare each other using the figure of merit denominated root mean squared error (RMSE), the filter that presents lower value of RMSE has better quality. On this research, five types of filters were used: Ram-Lak, Shepp-Logan, Cosine, Hamming and Hann filters. As results, all filters presented lower values of RMSE, that means the filters used have low stand deviation compared to the mass absorption coefficient, however, the Hann filter presented better RMSE and CNR compared to the others. (author)

  12. New methodology for analysis of diverting agent performance in unconsolidated sandstones with physical simulator using computerized tomography; Nova metodologia para analise de desempenho de agentes divergentes em arenitos inconsolidados com simuladores fsicos utilizando tomografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Joao Luiz Batista [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Fundacao COPPETEC. Lab. de Instrumentacao Nuclear], e-mail: jlbr.coppetec@petrobras.com.br; Queiroz Neto, Joao Crisosthomo de; D' Almeida, Arnaldo Rodrigues; Souza, Lenita Rangel de [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas da Petrobras (CENPES). Gerencia de Tecnologia e Engenharia de Pocos], e-mail: joaoqueiroz@petrobras.com.br; e-mail: arda@petrobras.com.br; e-mail: lenita@petrobras.com.br; Bianco, Luis Carlos Baralho [PETROBRAS, Rio de Janeiro, RJ (Brazil). Unidade de Negocio de Exploracao e Producao do Rio de Janeiro. Gerencia de Engenharia de Pocos], e-mail: lbianco@petrobras.com.br; Campo, Elisabete Ferreira [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas da Petrobras (CENPES). Gerencia de Tecnologia de Recuperacao e Analise de Reservatorios], e-mail: betefc@petrobras.com.br

    2006-12-15

    While oil and gas producer wells have the advantage of being able to naturally expel damaging particles produced during the drilling and/or completion phase, water injectors are prone to accumulating damaging substances during their operation . In order to remove those substances and restore the potential injectivity of these wells, acid jobs are usually required. One of the major challenges of these operations is to achieve successful treatment diversion. If the interval consists of layers with different permeabilities, the acid will preferably penetrate high permeable layers, leaving the zones of minor permeability without treatment. For diversion to occur, a highly effective material quantity and concentration needs to be applied. The diverting agent must also be non-damaging, low-cost and easy-to-use. The diverting agent studied performed well for permeabilities up to 3 Darcy. The main advantage of the product, besides its high divergence capacity, is the specific action of forming channels in the pores of the matrix where only oil can flow. Therefore, due to it's high hygroscopic characteristics, captures the water around the pores. Also , the product is capable of self-removal after treatment, with the oil produced in the treated well, which eliminates the need for subsequent treatments that would increase time and cost of the operation. In this study, an X-Ray Computerized Tomography (CT) scanner was used to evaluate in real-time the performance of the diverting agent in rock-fluid interactions. A special aluminum cell (physical simulator) was designed to simulate as closely as possible the conditions found in a real oil well. These conditions include, for example, pressure, temperature, fluid pressure injection, permeability, porosity and oil and water saturations of the studied reservoir. A sequence of tests that were performed in different unconsolidated sandstones, which simulated Campos Basin deep water fields, confirmed the system

  13. Non-destructive analysis and detection of internal characteristics of spruce logs through X computerized tomography; Detection et analyse non destructive de caracteristiques internes de billons d'epicea commun (PICEA ABIES (L.) KARST) par tomographie a rayons X

    Energy Technology Data Exchange (ETDEWEB)

    Longuetaud, F

    2005-10-15

    Computerized tomography allows a direct access to internal features of scanned logs on the basis of density and moisture content variations. The objective of this work is to assess the feasibility of an automatic detection of internal characteristics with the final aim of conducting scientific analyses. The database is constituted by CT images of 24 spruces obtained with a medical CT scanner. Studied trees are representative of several social status and are coming from four stands located in North-Eastern France, themselves are representative of several age, density and fertility classes. The automatic processing developed are the following. First, pith detection in logs dealing with the problem of knot presence and ring eccentricity. The accuracy of the localisation was less than one mm. Secondly, the detection of the sapwood/heart-wood limit in logs dealing with the problem of knot presence (main source of difficulty). The error on the diameter was 1.8 mm which corresponds to a relative error of 1.3 per cent. Thirdly, the detection of the whorls location and comparison with an optical method. Fourthly the detection of individualized knots. This process allows to count knots and to locate them in a log (longitudinal position and azimuth); however, the validation of the method and extraction of branch diameter and inclination are still to be developed. An application of this work was a variability analysis of the sapwood content in the trunk: at the within-tree level, the sapwood width was found to be constant under the living crown; at the between-tree level, a strong correlation was found with the amount of living branches. A great number of analyses are possible from our work results, among others: architectural analysis with the pith tracking and the apex death occurrence; analysis of radial variations of the heart-wood shape; analysis of the knot distribution in logs. (author)

  14. LUNGx Challenge for computerized lung nodule classification.

    Science.gov (United States)

    Armato, Samuel G; Drukker, Karen; Li, Feng; Hadjiiski, Lubomir; Tourassi, Georgia D; Engelmann, Roger M; Giger, Maryellen L; Redmond, George; Farahani, Keyvan; Kirby, Justin S; Clarke, Laurence P

    2016-10-01

    The purpose of this work is to describe the LUNGx Challenge for the computerized classification of lung nodules on diagnostic computed tomography (CT) scans as benign or malignant and report the performance of participants' computerized methods along with that of six radiologists who participated in an observer study performing the same Challenge task on the same dataset. The Challenge provided sets of calibration and testing scans, established a performance assessment process, and created an infrastructure for case dissemination and result submission. Ten groups applied their own methods to 73 lung nodules (37 benign and 36 malignant) that were selected to achieve approximate size matching between the two cohorts. Area under the receiver operating characteristic curve (AUC) values for these methods ranged from 0.50 to 0.68; only three methods performed statistically better than random guessing. The radiologists' AUC values ranged from 0.70 to 0.85; three radiologists performed statistically better than the best-performing computer method. The LUNGx Challenge compared the performance of computerized methods in the task of differentiating benign from malignant lung nodules on CT scans, placed in the context of the performance of radiologists on the same task. The continued public availability of the Challenge cases will provide a valuable resource for the medical imaging research community.

  15. O uso de tomografia computadorizada nas internações por Acidente Vascular Cerebral no Sistema Único de Saúde no Brasil Computerized tomography utilization for stroke inpatients in the Brazilian Health System

    Directory of Open Access Journals (Sweden)

    Cristina Lúcia Rocha Cubas Rolim

    2012-03-01

    Full Text Available O Acidente Vascular Cerebral é um dos principais motivos de internação no Sistema Único de Saúde. O exame de tomografia computadoriza tem sido indicado como o principal método diagnóstico de imagem para a definição do tratamento do Acidente Vascular Cerebral. O objetivo desse artigo é avaliar a utilização de exames de tomografia computadorizada em internações por Acidente Vascular Cerebral com base nas informações do Sistema de Informação Hospitalar do Sistema Único de Saúde. O universo de estudo incluiu as internações de pacientes adultos ocorridas no Brasil e financiadas pelo Sistema Único de Saúde entre abril de 2006 e dezembro de 2007. A análise dos dados foi descritiva para o conjunto de casos de Acidente Vascular Cerebral e para cada subgrupo separadamente. Das 328.087 internações por Acidente Vascular Cerebral, observou-se que em 73,5% o exame não foi realizado. Nas internações que realizaram tomografia computadorizada, 22,3% tiveram acesso a um exame e somente 4,2% a dois exames. Além de subutilizado, o exame de tomografia computadorizada, quando realizado, não trouxe melhora na codificação adequada do subgrupo da doença.Stroke is a leading reason for hospitalization in the Brazilian Health System. Computerized tomography has been indicated as the main diagnostic method to define stroke treatment. The aim of this paper was to evaluate the utilization of computerized tomography in hospitalizations due to stroke. The source of data was the Brazilian hospital information system. The study population comprised adult stroke inpatients in Brazil in the Brazilian Health System, between April 2006 and December 2007. Data analysis was descriptive for stroke and for each separate subgroup. Of the 328,087 stroke inpatients, 73.5% had not done a computerized tomography scan. Among hospitalizations that underwent a computed tomography scan, 22.3% had access to one test, and only 4.2% had two tests. Besides underuse

  16. Can carotid stenosis be operated without arteriography? Contribution of magnetic resonance and helical computerized tomography angiography; Peut-on operer une stenose carotidienne sans arteriographie? Apport de l`angioMR et/ou de l`angioscanner helicoidal

    Energy Technology Data Exchange (ETDEWEB)

    Auffrau-Calvier, E.; Kersaint-Gilly, A. de; Desal, H.A.; Viarouge, M.P.; Havet, T. [Hopital Laennec, 44 - Nantes (France)

    1996-09-01

    The aim of this work is to ascertain the role of the magnetic resonance angiography (MRA) and to compare it with the Doppler effect, the X-ray angiography and the new method of helical computerized tomography. Seventy one carotid bifurcations in 37 patients with suspected cerebral vascular events has been evaluated with the MRA and digitalized angiography, the reference method. The obtained data corroborate the good results proposed by other authors reporting in the literature and allow to propose this examination as a new means of investigating carotid bifurcations. Work with the helical computerized tomography appears to be promising too but there are few reported series. Therefore, there appears to be two interesting points: the reliability of distinguishing between very severe stenosis and occlusion, and the fine-tuned analysis of the plaque with detection of ulcerations. When a consistent approach is used to the evaluation of the carotid bifurcation, the Willis circle and the cerebral parenchyma, the MRA can complete the Doppler echo data and the preoperative arteriography can only be used in patients when the MRA and the Doppler echo results disagree. (authors)

  17. Seismic Traveltime Tomography Applied to Data from Miranga Field, Reconcavo Basin, Brazil

    Science.gov (United States)

    Bassrei, A.; Rodrigues, V.

    2015-12-01

    The growing global demand for hydrocarbons has tested the limits of oil exploration and exploitation technologies. Within the seismic methods, tomography is an alternative for the high resolution characterization of reservoirs, enabling a more efficient recovery of new as well as mature fields. In this work, seismic traveltime tomography in the transmission mode was applied to real data from the Miranga Field, Reconcavo Basin, State of Bahia, Brazil. This basin represents a landmark of oil exploration in Brazil and has been intensively studied since the 1950s. Today, the Reconcavo Basin is still the principal oil producer in the State of Bahia, but there is a demand for new technologies, especially for mature fields, to improve hydrocarbon recovery. The objective is to estimate the two-dimensional velocity distribution in the region between the two wells. We have used linearized inversion through the Levenberg-Marquardt scheme. The input data in the system are the traveltimes between the sources and the receivers and the distances propagated by each ray connecting such sources and receivers. Both inputs are provided through acoustic forward modeling. The conjugate gradient algorithm with regularization through derivative matrices was used as an inverse procedure. The tomographic inversion is an ill-posed problem because the existence, uniqueness and stability conditions are not completely satisfied. The linear system is regularized by derivative matrices derived to minimize the instability. This regularization procedure has a crucially important parameter called regularization parameter lambda. For the selection of lambda we used L-curve and Theta-curve. The estimated tomograms were consistent with previous geological knowledge of the area and the P-wave velocity range was consistent. The results showed that traveltime tomography is feasible for the characterization of reservoirs with a high rate of vertical change, similar to the Miranga Field.

  18. Investigations and improvements of digital holographic tomography applied for 3D studies of transmissive photonics microelements

    Science.gov (United States)

    Kujawinska, Malgorzata; Jozwicka, Agata; Kozacki, Tomasz

    2008-08-01

    In order to control performance of photonics microelements it is necessary to receive 3D information about their amplitude and phase distributions. To perform this task we propose to apply tomography based on projections gather by digital holography (DH). Specifically the DH capability to register several angular views of the object during a single hologram capture is employed, which may in future shorten significantly the measurement time or even allow for tomographic analysis of dynamic media. However such a new approach brings a lot of new issues to be considered. Therefore, in this paper the method limitations, with special emphasis on holographic reconstruction process, are investigated through extensive numerical experiments with special focus on 3D refractive index distribution determination.. The main errors and means of their elimination are presented. The possibility of 3D refractive index distribution determination by means of DHT is proved numerically and experimentally.

  19. Effects of fractionated doses of fast neutrons or photons on the canine brain: evaluation by computerized tomography and evoked response recording

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, E.W.; Davis, D.O.; Gaskill, J.W.; Deye, J.A.; Fisher, M.P.; Sloan, G.E.; Rogers, C.C.

    1980-12-01

    The use of fast neutrons in the treatment of cancer necessitates a knowledge of the normal tissue responses. This study was designed to compare the late effects of fractionated doses of fast neutrons with fractionated doses of photons on canine brains by evoked response recording and viewing computerized tomograms (CT). A relative biological effectiveness (RBE) of 4 was obtained for normal brain tissue assessed by mortality and onset of neurologic symptoms. Every three months post-irradiation, visual and sensory evoked responses were recorded. Changes over time appeared to be minimal; however, computerized tomographs showed marked brain shrinkage. A method of quantitating cerebrospinal fluid and parenchymal volumes from scans is described and future use of these CT ratios to generate dose response curves and RBE values is postulated.

  20. Joint body and surface wave tomography applied to the Toba caldera complex (Indonesia)

    Science.gov (United States)

    Jaxybulatov, Kairly; Koulakov, Ivan; Shapiro, Nikolai

    2016-04-01

    We developed a new algorithm for a joint body and surface wave tomography. The algorithm is a modification of the existing LOTOS code (Koulakov, 2009) developed for local earthquake tomography. The input data for the new method are travel times of P and S waves and dispersion curves of Rayleigh and Love waves. The main idea is that the two data types have complementary sensitivities. The body-wave data have good resolution at depth, where we have enough crossing rays between sources and receivers, whereas the surface waves have very good near-surface resolution. The surface wave dispersion curves can be retrieved from the correlations of the ambient seismic noise and in this case the sampled path distribution does not depend on the earthquake sources. The contributions of the two data types to the inversion are controlled by the weighting of the respective equations. One of the clearest cases where such approach may be useful are volcanic systems in subduction zones with their complex magmatic feeding systems that have deep roots in the mantle and intermediate magma chambers in the crust. In these areas, the joint inversion of different types of data helps us to build a comprehensive understanding of the entire system. We apply our algorithm to data collected in the region surrounding the Toba caldera complex (north Sumatra, Indonesia) during two temporary seismic experiments (IRIS, PASSCAL, 1995, GFZ, LAKE TOBA, 2008). We invert 6644 P and 5240 S wave arrivals and ~500 group velocity dispersion curves of Rayleigh and Love waves. We present a series of synthetic tests and real data inversions which show that joint inversion approach gives more reliable results than the separate inversion of two data types. Koulakov, I., LOTOS code for local earthquake tomographic inversion. Benchmarks for testing tomographic algorithms, Bull. seism. Soc. Am., 99(1), 194-214, 2009, doi:10.1785/0120080013

  1. Determination of the dose index in computerized tomography using thermoluminescent dosemeters; Determinacion del indice de dosis en tomografia computada usando dosimetros termoluminiscentes

    Energy Technology Data Exchange (ETDEWEB)

    Azorin, J.C.; Calderon, A. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada-IPN, 11500 Mexico D.F. (Mexico); Azorin, J. [UAM-I, 09340 Mexico D.F. (Mexico)

    2004-07-01

    In this work the obtained results of the determination of the dose index are presented in thorax studies in computed tomography and helical tomography carried out in Mexico using thermoluminescent dosemeters of LiF: Mg,Cu,P + Ptfe developed and manufactured in our country. The results showed that under similar conditions of irradiation and operation (pitch = 1), significant differences don't exist among the doses absorbed measures in the phantom due to the two types of used tomographs. (Author)

  2. Optical coherence tomography: a non-invasive technique applied to conservation of paintings

    Science.gov (United States)

    Liang, Haida; Gomez Cid, Marta; Cucu, Radu; Dobre, George; Kudimov, Boris; Pedro, Justin; Saunders, David; Cupitt, John; Podoleanu, Adrian

    2005-06-01

    It is current practice to take tiny samples from a painting to mount and examine in cross-section under a microscope. However, since conservation practice and ethics limit sampling to a minimum and to areas along cracks and edges of paintings, which are often unrepresentative of the whole painting, results from such analyses cannot be taken as representative of a painting as a whole. Recently in a preliminary study, we have demonstrated that near-infrared Optical Coherence Tomography (OCT) can be used directly on paintings to examine the cross-section of paint and varnish layers without contact and the need to take samples. OCT is an optical interferometric technique developed for in vivo imaging of the eye and biological tissues; it is essentially a scanning Michelson's interferometer with a "broad-band" source that has the spatial coherence of a laser. The low temporal coherence and high spatial concentration of the source are the keys to high depth resolution and high sensitivity 3D imaging. The technique is non-invasive and non-contact with a typical working distance of 2 cm. This non-invasive technique enables cross-sections to be examined anywhere on a painting. In this paper, we will report new results on applying near-infrared en-face OCT to paintings conservation and extend the application to the examination of underdrawings, drying processes, and quantitative measurements of optical properties of paint and varnish layers.

  3. Electrical Resistivity Tomography (ERT) Applied to Karst Carbonate Aquifers: Case Study from Amdoun, Northwestern Tunisia

    Science.gov (United States)

    Redhaounia, Belgacem; Ilondo, Batobo Ountsche; Gabtni, Hakim; Sami, Khomsi; Bédir, Mourad

    2016-04-01

    The Amdoun region is characterized by a high degree of karstification due to the climate impact (±1500 mm year-1) and the development of fracture network. Survey using electrical resistivity tomography (ERT) is deployed to provide a cost-effective characterization of the subsurface karst environments. A total of seven ERT profiles with lengths of 315 m were evaluated at the Béja governorate (NW Tunisia). The area represents a small syncline of Boudabbous limestone rocks (Lower Eocene), which is covered by a thin layer of clay. In this study, an ERT survey was conducted to examine the spatial distribution and shape of underground cavities in the karst area in Jebel Sabah anticline and Aïn Sallem-Zahret Medien syncline. In this study, geological, hydro-geological and electrical resistivity tomography (ERT) methods were applied to determine the geometry of the perched aquifer in the Amdoun region (NW Tunisia). The area is characterized by fractured and karstic limestone aquifer of Late Cretaceous (Abiod Fm.) and Lower Eocene (Boudabbous Fm.). The aquifers have a karstic functioning and drain aquifers of economical interest, despite some wells exploiting them. Seven resistivity profiles were conducted along the survey area at three sites. The orientation, extension and the degree of inclination of those profiles are shown in the location map. The correct resistivity data were interpreted using Earth Imager 2D software. The results of the interpreted geo-electrical sections showed that the resistivity of the carbonate aquifer varied between 2.5 to over 5794 Ωm. The thickness of the perched aquifer ranged from 15 to 50 m, while its depth from the surface lies between 10 and 60 m. The ERT not only provided precise near surface information, but was also very useful for establishing the 3D geometry and the position of several potential cavities and karts. The results show the presence of small to large isolated cavities at various depths. The low resistivity of cavities

  4. Contribution of 3D inversion of Electrical Resistivity Tomography data applied to volcanic structures

    Science.gov (United States)

    Portal, Angélie; Fargier, Yannick; Lénat, Jean-François; Labazuy, Philippe

    2016-04-01

    The electrical resistivity tomography (ERT) method, initially developed for environmental and engineering exploration, is now commonly used for geological structures imaging. Such structures can present complex characteristics that conventional 2D inversion processes cannot perfectly integrate. Here we present a new 3D inversion algorithm named EResI, firstly developed for levee investigation, and presently applied to the study of a complex lava dome (the Puy de Dôme volcano, France). EResI algorithm is based on a conventional regularized Gauss-Newton inversion scheme and a 3D non-structured discretization of the model (double grid method based on tetrahedrons). This discretization allows to accurately model the topography of investigated structure (without a mesh deformation procedure) and also permits a precise location of the electrodes. Moreover, we demonstrate that a complete 3D unstructured discretization limits the number of inversion cells and is better adapted to the resolution capacity of tomography than a structured discretization. This study shows that a 3D inversion with a non-structured parametrization has some advantages compared to classical 2D inversions. The first advantage comes from the fact that a 2D inversion leads to artefacts due to 3D effects (3D topography, 3D internal resistivity). The second advantage comes from the fact that the capacity to experimentally align electrodes along an axis (for 2D surveys) depends on the constrains on the field (topography...). In this case, a 2D assumption induced by 2.5D inversion software prevents its capacity to model electrodes outside this axis leading to artefacts in the inversion result. The last limitation comes from the use of mesh deformation techniques used to accurately model the topography in 2D softwares. This technique used for structured discretization (Res2dinv) is prohibed for strong topography (>60 %) and leads to a small computational errors. A wide geophysical survey was carried out

  5. Study of a methodology for the quality control and radioprotection program in computerized tomography; Estudo de uma metodologia para programa de controle da qualidade e radioprotecao em tomografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Tiecher, Maria Ester Souza

    1998-09-01

    The objective of this work is to develop a methodology for the quality control program computerized tomography (CT) sector at the Hospital Central do Exercito (HCE). The methodology was developed based on the study of physical parameters related to the equipment efficiency and the radiation dose, Computed Tomography Dose Index. The study established a set of tests necessary to determine the following physical parameters: spatial resolution, resolution of low contrast, linearity, uniformity of CT number, noise, slice thickness and artefacts. In order to evaluate the influence of the variables at the different parameters it was made some changes at the Standard routine service for the case Head and Abdomen. In sight of an optimization, the parameter study correlated the following variables; tube current, scanning time, image reconstruction filter and slice thickness. The equipment used for the analysis was a pencil-shaped ionization chamber. This kind of dosimeter is widely used for quality control programs mainly due its easy handily and the ready results, for a phantom of the human body. As a result of the work, it has been provided an Instruction Handbook, based on the equipment handbook, including a list of physical parameters to be controlled and that improves the quality control in the Radiological Department of the Hospital Central do Exercito. (author) 35 refs., 55 figs., 65tabs.

  6. A new computerized ionosphere tomography model using the mapping function and an application to the study of seismic-ionosphere disturbance

    Science.gov (United States)

    Kong, Jian; Yao, Yibin; Liu, Lei; Zhai, Changzhi; Wang, Zemin

    2016-08-01

    A new algorithm for ionosphere tomography using the mapping function is proposed in this paper. First, the new solution splits the integration process into four layers along the observation ray, and then, the single-layer model (SLM) is applied to each integration part using a mapping function. Next, the model parameters are estimated layer by layer with the Kalman filtering method by introducing the scale factor (SF) γ to solve the ill-posed problem. Finally, the inversed images of different layers are combined into the final CIT image. We utilized simulated data from 23 IGS GPS stations around Europe to verify the estimation accuracy of the new algorithm; the results show that the new CIT model has better accuracy than the SLM in dense data areas and the CIT residuals are more closely grouped. The stability of the new algorithm is discussed by analyzing model accuracy under different error levels (the max errors are 5TECU, 10TECU, 15TECU, respectively). In addition, the key preset parameter, SFγ , which is given by the International Reference Ionosphere model (IRI2012). The experiment is designed to test the sensitivity of the new algorithm to SF variations. The results show that the IRI2012 is capable of providing initial SF values. Also in this paper, the seismic-ionosphere disturbance (SID) of the 2011 Japan earthquake is studied using the new CIT algorithm. Combined with the TEC time sequence of Sat.15, we find that the SID occurrence time and reaction area are highly related to the main shock time and epicenter. According to CIT images, there is a clear vertical electron density upward movement (from the 150-km layer to the 450-km layer) during this SID event; however, the peak value areas in the different layers were different, which means that the horizontal movement velocity is not consistent among the layers. The potential physical triggering mechanism is also discussed in this paper. Compared with the SLM, the RMS of the new CIT model is improved by

  7. Clinical application of Computerized tomography in minipercutaneous nephrolithotripsy%CT在微创经皮肾镜取石术中的应用

    Institute of Scientific and Technical Information of China (English)

    傅发军; 周刚; 杨健; 陈新辉

    2011-01-01

    [Objective] To study the clinical value of computed tomography (CT) for mini-preoperataneous nephrolithotomy (MPCNL). [Methods] 899 patients with renal calculi or upper ureteral calculi diagnosed by type B ultrasound, KUB, or KUB+IVU were analyzed retrospectively. The relation between the operative effect and application of CT before operation was evaluated. [ Results ] Of 899 patients, the mPCNL was not applicable to the following ones:3 renal tumor with calcification, 4 calcification of renal parenchyma or vessel, 27 renal lithiasis of nonfunctional atrophic kidney, 7 lithiasis with calcification and 2 renal cyst with calcification. Of the other 856 ones applied with the mPCNL, 27 suffered from retained calculus after the operation, 7 undertook accompanied injury of puncture and 4 undertook severe hemorrhage after operation. [Conclusions] The application of CT before operation could screen patients who are not applicable to the mPCNL and enforce the clearance of calculus and reduce the complications. CT should be the regular examination before mPCNL.%目的 探讨CT在微创经皮肾镜取石术中的应用价值.方法 2005年03月~2008年12月选择该院899例患者,术前经B超、KUB或KUB+IVU诊断为肾结石和(或)输尿管上段结石,评估术前是否进行CT检查对手术效果的影响.结果 899例患者术前经CT筛查,肾肿瘤并钙化3例,肾实质或血管钙化4例,萎缩无功能肾肾结石27例,UPJO并结石7例、肾囊肿并钙化2例,该组患者不适合行经皮肾镜碎石取石术;856例行皮肾镜取石术,出现术后残石27例;出现穿刺副损伤7例;出现术后大出血4例.结论 术前CT检查可以筛查不适合行微创经皮肾镜取石术的病例,并有效提高结石清除率,降低手术并发症,建议作为经皮肾镜碎石取石术前常规检查项目.

  8. Neutron tomography as a reverse engineering method applied to the IS-60 Rover gas turbine

    CSIR Research Space (South Africa)

    Roos, TH

    2011-09-01

    Full Text Available Probably the most common method of reverse engineering in mechanical engineering involves measuring the physical geometry of a component using a coordinate measuring machine (CMM). Neutron tomography, in contrast, is used primarily as a non...

  9. Optical coherence tomography applied to tests of skin care products in humans--a case study.

    Science.gov (United States)

    Vasquez-Pinto, L M C; Maldonado, E P; Raele, M P; Amaral, M M; de Freitas, A Z

    2015-02-01

    When evaluating skin care products for human skin, quantitative test methods need to be simple, precise and reliable. Optical coherence tomography (OCT), provides high-resolution sectional images of translucent materials to a depth of a few millimeters, a technique usually applied to medical measurements in ophthalmology and dermatology. This study aimed to demonstrate the application of OCT as the main technique for monitoring changes in skin topography during tests of a wrinkle-reduction product in humans. We used a commercial OCT apparatus to perform clinical examinations of skin roughness in treated and non-treated sites in the periorbital region of thirty human voluntaries who were using an anti-aging product commercially available: Natura Chronos® Flavonóides de Passiflora 45+ FPS15, from Natura Cosméticos, Brazil. Measurements were performed days 0, 7, 14 and 28 of treatment. Equipment and software allowed real-time recording of skin roughness parameters and wrinkle depths. The OCT measurements have allowed the monitoring of changes in skin roughness, which have shown reduction in treated sites around 10%. The obtained depth distributions also indicate reduction in the occurrence of wrinkles deeper than 170 μm. The verified results are consistent with those typically obtained after successful treatment with modern anti-aging products. By using the OCT technique, it was possible to quantify changes in skin roughness and in the distribution of depths of skin wrinkles, with adequate sensitivity. OCT imaging allows the direct visualization of the skin topography with resolution of micrometers, a reliable and interactive tool for clinical use. Therefore, for the first time, we demonstrated the use of OCT technique to verify the efficacy of cosmetic products in real time. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Evaluation of dosimetry and image quality of computerized tomography abdomen protocols; Avaliacao de dose e qualidade da imagem em protocolos de abdomen em tomografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Maues, Nadine H.P.B.; Alves, Allan F.F.; Bacchim Neto, Fernando A.; Pina, Diana R. [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil)

    2016-07-01

    In this study, we evaluate the dosimetry and image quality of computed tomography multislice abdomen protocols for different tube current modulation techniques (ATCM). We used the 16-slice Toshiba Activion CT scanner with the 'SureExposure3D' ATCM system. Thermoluminescent dosimeters were placed inside the anthropomorphic phantom Alderson-Rando for dosimetric assessments. An analytical phantom was used for the objective evaluation of image quality. It is observed that the higher standard deviation technique (SD) has the lowest value of effective dose. The use of different tube current modulation techniques showed significant reduction of radiation doses for the abdomen exams in computed tomography. The ATCM protocols can be an excellent alternative to dose reduction in CT scans, since it does not impair the diagnostic image quality. (author)

  11. Radiation condition in computerized tomography (CT): determination and calibration of dosemeters; Condicoes de radiacao em tomografia computadorizada (TC): determinacao e calibracao de dosimetros

    Energy Technology Data Exchange (ETDEWEB)

    Adrade, L.C.; Peixoto, J.G.P., E-mail: lucio-andrade@hotmail.com [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2016-07-01

    RQT is the standard for radiation conditions in computed tomography . It simulates a beam unrelieved of a CT scanner . The camera pencil ionization dosimeter is used in CT. The LNMRI become known characterization of RQT radiation conditions and the secondary standard calibration for type pencil ionisation chambers in its lab. The obtained beam has the characteristics required by IEC 61267. The results of the calibration presented combined uncertainty expanded to 95.45% from 2.22% . (author)

  12. Bronchial asthma: correlation of high resolution computerized tomography findings with clinical data; Asma bronquica: correlacao de achados em tomografia computadorizada de alta resolucao com dados clinicos

    Energy Technology Data Exchange (ETDEWEB)

    Mogami, Roberto [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Servico de Radiologia; Marchiori, Edson [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Dept. de Radiologia; Kirk, Kennedy; Capone, Domenico [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Servico de Pneumologia; Daltro, Pedro [Instituto Fernandes Figueira, Rio de Janeiro, RJ (Brazil). Servico de Radiologia

    1999-04-01

    In this work we did a sectional study of 31 asthmatic patients with several levels of disease severity, which were submitted to high resolution computed tomography of the thorax and spirometry, between the months of July, 1995 and August, 1997. The tomographic findings were correlated with the clinical classification of the patients and the most frequent tomographic findings were bronchial wall thickening, bronchial dilatation, air trapping, centrilobular opacities, cicatricial linear shadows, mucoid impaction, emphysema and atelectasis. In asthmatic patients of long duration we observed small airway disease and irreversible lesions as the predominant findings. In smoking patients there was no high frequency of emphysema. (author)

  13. Comparison of the changes of alveolar bone thickness in maxillary incisor area in extraction and non-extraction cases: computerized tomography evaluation

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Barroso Picanço

    2013-10-01

    Full Text Available OBJECTIVE: To compare, through computed tomography, alveolar bone thickness changes at the maxillary incisors area during orthodontic treatment with and without tooth extraction. METHODS: Twelve patients were evaluated. They were divided into 2 groups: G1 - 6 patients treated with extraction of right and left maxillary first premolars, with mean initial age of 15.83 years and mean treatment length of 2.53 years; G2 - 6 patients treated without extraction, with mean initial age of 18.26 years and mean treatment length of 2.39 years. Computed tomographies, lateral cephalograms and periapical radiographs were used at the beginning of the treatment (T1 and 18 months after the treatment had started (T2. Extraction space closure occurred in the extraction cases. Intragroup and intergroup comparisons were performed by dependent and independent t test, respectively. RESULTS: In G1, the central incisor was retracted and uprighted, while in G2 this tooth showed vestibularization. Additionally, G1 presented a higher increase of labial alveolar bone thickness at the cervical third in comparison with G2. The incidence of root resorption did not present significant differences between groups. CONCLUSION: There were no changes in alveolar bone thickness when extraction and nonextraction cases were compared, except for the labial alveolar bone thickness at the cervical third of maxillary incisors.

  14. Regional cerebral blood flow in acute stage with ischemic cerebrovascular disease by xenon-133 inhalation and single photon emission computerized tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kurokawa, Hiroyuki; Iino, Katsuro; Kojima, Hisashi; Saito, Hitoshi; Suzuki, Mikio; Watanabe, Kazuo; Kato, Toshiro

    1987-05-01

    Single photon emission computed tomography (SPECT) with xenon-133 inhalation method was undertaken within 48 hr after the onset in 68 patients with ischemic cerebrovascular disease. The results for regional cerebral blood flow (rCBF) were compared with concurrently available computed tomography (CT) scans. In patients with cerebral infarction, SPECT detected ischemic lesions earlier than CT, with the detectability being 92 %. The area with a decreased blood flow, as seen on SPECT, was more extensive than the low density area on CT, with a concomitant decrease in blood flow in the contralateral cerebral hemisphere. Crossed cerebellar diaschisis was associated with stenosis of the internal carotid artery in 50 % (7/14), and with stenosis of the middle cerebral artery in 35 % (9/26). Abnormal SPECT findings were seen in 47 % (8/17) of the patients with transient ischemic attack (TIA). Five TIA patients had a decreased rCBF on SPECT, which was not provided by CT scans. On the contrary, small infarct lesions in the cerebral basal ganglia, as observed in 4 patients, was not detected by SPECT, but detected by CT. This may imply the limitations of SPECT in the detection of deep-seated lesions of the cerebrum. The results led to the conclusion that SPECT can be performed safely even in acute, seriously ill patients to know changes in rCBF because it is noninvasive and is capable of being repeated in a short time. (Namekawa, K.).

  15. Comparison of the efficacy of ethylene diamine tetraacetic acid and maleic acid in the removal of three calcium hydroxide intra-canal dressings: A spiral computerized tomography volumetric analysis

    Directory of Open Access Journals (Sweden)

    Mohan Thomas Nainan

    2013-01-01

    Full Text Available Aim: To assess the efficacy of 17% ethylene diamine tetra acetic acid and 7% maleic acid in the removal of 3 calcium hydroxide preparations placed as intracanal medicaments. Materials and Methods: The root canals of 60 single rooted premolars were prepared with a step back technique and randomly assigned into 3 experimental groups (n = 20. Group A was filled with plain calcium hydroxide mixed with distilled water in which barium sulfate was added for radio opacity, Group B was filled with Apexcal and Group C was filled with Metapex. After 7 days each group was divided into 2 sub groups (n = 10. The medicaments were retrieved with 17% EDTA (first sub group and 7% maleic acid (second sub group. Along with the above irrigants manual and ultrasonic agitation was used. The pre and post removal volume of medicaments in root canals were measured using spiral computerized tomography. The percentage difference was calculated and statistically analyzed using Kruskal Wallis and Mann Whitney U test. Results: 17% EDTA and 7% maleic acid efficiently removed calcium hydroxide, distilled water mixture (P = 0.218 and Apexcal (P = 0.684, whereas 7% maleic acid showed better retrieval capability of Metapex than 17% EDTA (P = 0.002. Conclusion: Calcium hydroxide, distilled water mixture and polyethylene glycol based calcium hydroxide were efficiently removed by 17% EDTA and 7% maleic acid. 7% maleic acid removed silicone oil based calcium hydroxide preparation better than 17% EDTA.

  16. A comprehensive diagnostic approach using galactomannan, targeted β-d-glucan, baseline computerized tomography and biopsy yields a significant burden of invasive fungal disease in at risk haematology patients.

    Science.gov (United States)

    Ceesay, M Mansour; Desai, Sujal R; Berry, Lisa; Cleverley, Joanne; Kibbler, Christopher C; Pomplun, Sabine; Nicholson, Andrew G; Douiri, Abdel; Wade, Jim; Smith, Melvyn; Mufti, Ghulam J; Pagliuca, Antonio

    2015-01-01

    Invasive fungal disease (IFD) is difficult to diagnose. We investigated the incidence of IFD and risk factors using the revised European Organization for Research and Treatment of Cancer (EORTC) and the Mycoses Study Group (MSG) definitions. Patients (N = 203) undergoing intensive therapy with expected neutropenia ≥10 d were recruited prospectively and followed for a median (range) of 556 (12-730) d. Baseline chest computerized tomography (CT) was performed pre-therapy. Twice-weekly surveillance with galactomannan (GM) was combined with targeted β-d-glucan (BDG) testing on patients with possible IFD or who were GM-positive. Tissue diagnosis was obtained whenever possible. The cumulative incidence of proven/probable IFD among the 202 evaluable cases after 2 years follow-up was 21%, including 14 proven and 30 probable IFDs. Using either GM or BDG as the sole biomarker (plus host and clinical evidence) the apparent overall incidence of proven/probable IFD was 11% and 16%, respectively. Combined GM/BDG detected all biopsy-proven mould IFD. Baseline CT abnormalities were found in 76/202 (38%) patients. Baseline CT abnormalities and Karnofsky score 10 d and bacteraemia were independent risk factors associated with greater than twofold increased IFD risk. This combined diagnostic approach identified a high incidence of IFD and important risk factors in this cohort.

  17. Electrical resistivity tomography applied to a complex lava dome: 2D and 3D models comparison

    Science.gov (United States)

    Portal, Angélie; Fargier, Yannick; Lénat, Jean-François; Labazuy, Philippe

    2015-04-01

    The study of volcanic domes growth (e.g. St. Helens, Unzen, Montserrat) shows that it is often characterized by a succession of extrusion phases, dome explosions and collapse events. Lava dome eruptive activity may last from days to decades. Therefore, their internal structure, at the end of the eruption, is complex and includes massive extrusions and lava lobes, talus and pyroclastic deposits as well as hydrothermal alteration. The electrical resistivity tomography (ERT) method, initially developed for environmental and engineering exploration, is now commonly used for volcano structure imaging. Because a large range of resistivity values is often observed in volcanic environments, the method is well suited to study the internal structure of volcanic edifices. We performed an ERT survey on an 11ka years old trachytic lava dome, the Puy de Dôme volcano (French Massif Central). The analysis of a recent high resolution DEM (LiDAR 0.5 m), as well as other geophysical data, strongly suggest that the Puy de Dôme is a composite dome. 11 ERT profiles have been carried out, both at the scale of the entire dome (base diameter of ~2 km and height of 400 m) on the one hand, and at a smaller scale on the summit part on the other hand. Each profile is composed of 64 electrodes. Three different electrode spacing have been used depending on the study area (35 m for the entire dome, 10 m and 5 m for its summit part). Some profiles were performed with half-length roll-along acquisitions, in order to keep a good trade-off between depth of investigation and resolution. Both Wenner-alpha and Wenner-Schlumberger protocols were used. 2-D models of the electrical resistivity distribution were computed using RES2DINV software. In order to constrain inversion models interpretation, the depth of investigation (DOI) method was applied to those results. It aims to compute a sensitivity index on inversion results, illustrating how the data influence the model and constraining models

  18. Piecewise-Constant-Model-Based Interior Tomography Applied to Dentin Tubules

    Directory of Open Access Journals (Sweden)

    Peng He

    2013-01-01

    Full Text Available Dentin is a hierarchically structured biomineralized composite material, and dentin’s tubules are difficult to study in situ. Nano-CT provides the requisite resolution, but the field of view typically contains only a few tubules. Using a plate-like specimen allows reconstruction of a volume containing specific tubules from a number of truncated projections typically collected over an angular range of about 140°, which is practically accessible. Classical computed tomography (CT theory cannot exactly reconstruct an object only from truncated projections, needless to say a limited angular range. Recently, interior tomography was developed to reconstruct a region-of-interest (ROI from truncated data in a theoretically exact fashion via the total variation (TV minimization under the condition that the ROI is piecewise constant. In this paper, we employ a TV minimization interior tomography algorithm to reconstruct interior microstructures in dentin from truncated projections over a limited angular range. Compared to the filtered backprojection (FBP reconstruction, our reconstruction method reduces noise and suppresses artifacts. Volume rendering confirms the merits of our method in terms of preserving the interior microstructure of the dentin specimen.

  19. Clinical manifestations in patients with computerized tomography diagnosis of neurocysticercosis; Manifestacoes clinicas de pacientes com diagnostico de neurocisticercose por tomografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Pfuetzenreiter, Marcia Regina [Universidade do Estado de Santa Catarina (UDESC), Florianopolis, SC (Brazil). Dept. de Medicina Veterinaria Preventiva e Tecnologia]. E-mail: a2mrp@cav.udesc.br; Avila-Pires, Fernando Dias de [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Saude Publica

    1999-09-01

    A survey was conducted in the urban area of Lages using patients who had been submitted to a computed tomography of the skull in the period of March-December, 1996, for different reasons. Forty-two patients with a provisional diagnosis of neurocysticercosis, and 57 negatives were personally interviewed by one of the authors (Pfuetzenreiter), using a semi-structured procedure. More individuals with a provisional diagnostic of neurocysticercosis reported clinical manifestations related to this infection than those found negative. this difference is more marked among women, except in relation to convulsions, more frequently reported by men (19.05%) than by women (7.14%). The greater percentage of inactive forms (83.33%0 and a longer history of perceived symptoms among those positives suggest that the condition is not new. (author)

  20. Research on ionospheric tomography based on variable pixel height

    Science.gov (United States)

    Zheng, Dunyong; Li, Peiqing; He, Jie; Hu, Wusheng; Li, Chaokui

    2016-05-01

    A novel ionospheric tomography technique based on variable pixel height was developed for the tomographic reconstruction of the ionospheric electron density distribution. The method considers the height of each pixel as an unknown variable, which is retrieved during the inversion process together with the electron density values. In contrast to conventional computerized ionospheric tomography (CIT), which parameterizes the model with a fixed pixel height, the variable-pixel-height computerized ionospheric tomography (VHCIT) model applies a disturbance to the height of each pixel. In comparison with conventional CIT models, the VHCIT technique achieved superior results in a numerical simulation. A careful validation of the reliability and superiority of VHCIT was performed. According to the results of the statistical analysis of the average root mean square errors, the proposed model offers an improvement by 15% compared with conventional CIT models.

  1. The early-stage diagnosis of albinic embryos by applying optical coherence tomography

    Science.gov (United States)

    Yang, Bor-Wen; Wang, Shih-Yuan; Wang, Yu-Yen; Cai, Jyun-Jhang; Chang, Chung-Hao

    2013-09-01

    Albinism is a kind of congenital disease of abnormal metabolism. Poecilia reticulata (guppy fish) is chosen as the model to study the development of albinic embryos as it is albinic, ovoviviparous and with short life period. This study proposed an imaging method for penetrative embryo investigation using optical coherence tomography. By imaging through guppy mother’s reproduction purse, we found the embryo’s eyes were the early-developed albinism features. As human’s ocular albinism typically appear at about four weeks old, it is the time to determine if an embryo will grow into an albino.

  2. Computerized tomography of chest in emphysema and interstitial diseases diagnosis. Tomografia computerizada del torax de alta resolucion en el diagnostico de enfisema y enfermedad intersticial

    Energy Technology Data Exchange (ETDEWEB)

    Souto Bayarri, M.; Malagari, K.; Ibarburen, C.; Arenas, G.; Correa Pombo, J.; Garcia Tahoces, P.; Tucker, D.; Barnes, G.T.; Luna, R.; Zerhouni, E.A.; Fraser, R.G.; Vidal Carrerira, J.J. (Hospital General de Galicia, Santiago de Compostela (Spain))

    1994-01-01

    To study the effect of increasing the spatial resolution on thin section (1.5 mm) computed tomography (CT) of the chest, we compared images reconstructed with the standard algorithm (SA) to three other images obtained with (1) a high spatial frequency algorithm, (2) retrospective targeting to a small field of view (FOV) reconstructed with the high spatial frequency algorithm, and (3) the same high spatial frequency algorithm with images acquired with the small (0.6 mm) rather the large (0.9 mm) focal spot. Examinations were performed on a phantom, on normal subjects, and on patients with emphysema and other diffuse lung diseases. Modulation transfer function (MTF) calculations revealed that higher resolution was achieved on the small focal spot and high spatial frequency algorithm than on the standard algorithm. Evaluation of the four images from 25 normal subjects, 16 patients with emphysema and 9 with interstitial disease was performed by means of an ROC study. Results from the areas under the ROC curves, sensitivity and specificity have shown that images reconstructed with the high spatial frequency algorithm were preferred. We conclude that the use of a high spatial frequency algorithm increases spatial resolution and improves visibility of lung parenchyma. Although more evaluation is needed, the potential of increasing spatial resolution further by using a smaller focal spot is currently limited by the mas Available per slice and the associated increased level of quantum noise. (Author)

  3. Preliminary tests in skull pediatric phantom for dosimetry in computerized tomography; Testes preliminares em um simulador pediatrico de cranio para dosimetria em tomografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Elaine Wirney; Potiens, Maria da Penha de A., E-mail: elainewirney@uso.br, E-mail: mppalbu@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2014-07-01

    Computed tomography (CT) is one of the techniques in the field of radiology with striking technological advance in recent years. One reason for this was the increased number of channels associated with the increased power of the X-ray tube. These conditions allowed the equipment high speed in the acquisition of the cuts, reducing the patient exposure time essential characteristic for the increase of its use in pediatric patients. In this context, were developed a new pediatric skull simulator to analyze the results of measurements performed in laboratory and clinic beams with the objective of creation and use of diagnostic reference levels observing risks stochastic effects and assessing the reduction of absorbed doses in patients undergoing growing. Preliminary tests performed in clinical beams showed C{sub w} values: 2.525 ± 0.212 mGy for the developed simulator quoted and 3.362 ± 0.282 mGy for a simulator developed by IPEN called standard, both being between uncertainty values of 8.4% and 14.4% suggested by TRS number 457.

  4. Characterization of radiation beam filtration in computerized tomography equipments. Dosimetric influence; Caracterizacion de la filtracion del haz de radiacion en equipos de tomografia computarizada. Influencia dosimetrica

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Tortosa, M.; Echevarne, M. [Universitat Rovira i Virgili (Spain); Calzado Cantera, A. [Universidad Complutense (Spain)

    2000-07-01

    The basic dosimetric quantities used in CT to assess doses to patient are the computed tomography dose index (CTDI) which can be determined either from measurements free-in-air or in standard head or body phantoms. CTDI values measured for different type of scanners can present high differences (up to a factor two). These differences are mainly due to differences in quality of the X ray beam as a consequence of differences in physical filtration. The filters used varied widely according to the manufacturer and model of scanner. Some scanners use a single fixed absorber, while others utilize two or more absorbers devoted specifically to anatomical areas (body or head) or different kind of examinations (pediatric,.). A good knowledge of the features of these absorbers (equivalent thickness and shape) is very useful in order to compare dose and to optimize the procedures for clinical use. however, such information is not always available and the assessment of the total filtration after installation of the scanners is seldom tackled. Dose measurements have been performed in order to determine the beam filtration and its influence on dose for a sample of seven third generation CT scanners. Measurements were conducted according to the ImPACT protocol, prepared specifically for the CT Scanner Dose Survey, in which we were participating. The investigated parameters were the half value layer and CT dose indexes (measured free-in-air and within phantoms), and an operational description of the shaping filters after selectable FOV values, as well. (Author) 32 refs.

  5. Dose optimization in adult patients exams in a computerized tomography service; Otimizacao de dose em exames de pacientes adultos em um servico de tomografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Pimentel, Juliana; Finatto, Jerusa D.; Silva, Ana Maria Marques da, E-mail: ana.marques@pucrs.br [Pontificia Universidade Catolica do Rio Grande do Sul (PUCRS), Porto Alegre, RS (Brazil); Froner, Ana Paula P. [CDI Tomografia e Ressonancia Magnetica, Porto Alegre, RS (Brazil)

    2013-08-15

    This paper presents a study of dose optimization in computed tomography X-ray of skull, chest and abdomen of adult patients, performed in a diagnostic imaging service in a large hospital. Images of a simulated dose phantom were acquired and the kVp, mAs, pitch, thickness and CTDI{sub vol} were collected directly from the equipment. Using the PACS system, regions of interest were delineated, where the mean and standard deviation of CT numbers for each protocol were been calculated. The optimization took into account the maintenance of the CT number and noise from images acquired with clinical protocols. It was observed that the protocols used in the service, in general, exhibit a low dose, despite the great variability among the different professional shifts. In examinations of the chest, skull and abdomen, changes in the values of mAs and pitch were suggested, allowing dose reductions (60%, 17% and 19%, respectively), without compromising the image diagnostic quality. (author)

  6. A comparison of quantitative reconstruction techniques for PIXE-tomography analysis applied to biological samples

    Energy Technology Data Exchange (ETDEWEB)

    Beasley, D.G., E-mail: dgbeasley@ctn.ist.utl.pt [IST/C2TN, Universidade de Lisboa, Campus Tecnológico e Nuclear, E.N.10, 2686-953 Sacavém (Portugal); Alves, L.C. [IST/C2TN, Universidade de Lisboa, Campus Tecnológico e Nuclear, E.N.10, 2686-953 Sacavém (Portugal); Barberet, Ph.; Bourret, S.; Devès, G.; Gordillo, N.; Michelet, C. [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Le Trequesser, Q. [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB, UPR9048) CNRS, Université de Bordeaux, 87 avenue du Dr. A. Schweitzer, Pessac F-33608 (France); Marques, A.C. [IST/IPFN, Universidade de Lisboa, Campus Tecnológico e Nuclear, E.N.10, 2686-953 Sacavém (Portugal); Seznec, H. [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Silva, R.C. da [IST/IPFN, Universidade de Lisboa, Campus Tecnológico e Nuclear, E.N.10, 2686-953 Sacavém (Portugal)

    2014-07-15

    The tomographic reconstruction of biological specimens requires robust algorithms, able to deal with low density contrast and low element concentrations. At the IST/ITN microprobe facility new GPU-accelerated reconstruction software, JPIXET, has been developed, which can significantly increase the speed of quantitative reconstruction of Proton Induced X-ray Emission Tomography (PIXE-T) data. It has a user-friendly graphical user interface for pre-processing, data analysis and reconstruction of PIXE-T and Scanning Transmission Ion Microscopy Tomography (STIM-T). The reconstruction of PIXE-T data is performed using either an algorithm based on a GPU-accelerated version of the Maximum Likelihood Expectation Maximisation (MLEM) method or a GPU-accelerated version of the Discrete Image Space Reconstruction Algorithm (DISRA) (Sakellariou (2001) [2]). The original DISRA, its accelerated version, and the MLEM algorithm, were compared for the reconstruction of a biological sample of Caenorhabditis elegans – a small worm. This sample was analysed at the microbeam line of the AIFIRA facility of CENBG, Bordeaux. A qualitative PIXE-T reconstruction was obtained using the CENBG software package TomoRebuild (Habchi et al. (2013) [6]). The effects of pre-processing and experimental conditions on the elemental concentrations are discussed.

  7. Fluorescence tomography applied to prostate cancer diagnosis using white pulsed laser

    Science.gov (United States)

    Daures, A.; Boutet, J.; Hervé, L.; Sauze, R.; Puszka, A.; Heinrich, E.; Grenier, N.; Dinten, J. M.

    2013-03-01

    Prostate cancer diagnosis is based on PSA rate measurement and ultrasound guided biopsy. Recently criticized for its lack of specificity, new approaches are currently investigated: MRI, elastography, TEP, NIRS and Time Resolved (TR) fluorescence tomography. The advantage of TR fluorescence tomography relies on its good complementarity with the standard ultrasound protocol and on the possible localization of prostate tumors marked by specific probes. After a first TR system based on a bulky titanium-sapphire laser, we designed a new one taking advantage of a more compact white pulsed laser (supercontinuum). The improved compactness is now fully compatible with clinical environment. The light, filtered by two linear variable filters to select a 770+/-20 nm window, is driven to the transrectal probe which also collects the fluorescence light emitted by the marker. The signal is detected by photomultipliers connected to TCSPC boards. A reconstruction algorithm based on intensities and time of flight allows a fast localization of the fluorophore. We compared the performances of the new white laser system to the previous titanium-sapphire on prostate mimicking phantoms. The laser power delivered on the phantom by the new laser appeared to be suitable to fluorescence measurements, just below cutaneous maximum permitted exposure. The new system allowed us to localize fluorescent inclusions of a fluorescent nanoemulsion at fixed positions inside a prostate mimicking phantom.

  8. Computerizing clinical practice guidelines

    DEFF Research Database (Denmark)

    Lyng, Karen Marie

    . The analysis focuses on the emergence of general clinical work practice demands on guidance • An analysis of guidance demands from clinical work practice and business strategy, focusing on implications for the design of computerised CPGs. In my research, I have applied observation studies, interviews...... is comprised by fieldwork in three oncology departments and a case study of advanced life support. Although close to all patients within oncology are treated according to a CPG, I found limited application of physical CPGs and web-based CPG portals. However, I found comprehensive application of activity...... feasible • Designed in a way that provides room for local adaptations of guidance • Designed with focus on specific business strategic aims Further, based on my findings, I will suggest that design of computerized CPGs should be based on: 1) scrutinization of the clinical work practice, 2) articulation...

  9. Comparing non contrast computerized tomography criteria versus dual X-ray absorptiometry as predictors of radio-opaque upper urinary tract stone fragmentation after electromagnetic shockwave lithotripsy.

    Science.gov (United States)

    Hameed, Diaa A; Elgammal, Mohammed A; ElGanainy, Ehab O; Hageb, Adel; Mohammed, Khaled; El-Taher, Ahmed Mohamed; Mostafa, Mostafa Mohamed; Ahmed, Abdelfatah Ibrahim

    2013-11-01

    The objective of this study was to assess the value of dual X-ray absorptiometry (DXA) in comparison to non contrast computed tomography (NCCT) density as possible predictors of upper urinary tract stone disintegration by shock wave lithotripsy (SWL). This study included 100 consecutive patients, with solitary renal stone 0.5-2 cm or upper ureteral stone up to 1 cm. DXA to calculate stone mineral density (SMD) and stone mineral content (SMC) was done. NCCT was performed to measure Hounsfield units (HU). SWL was performed with an electromagnetic lithotripsy, plain X-ray documented disintegration after SWL. Successful treatment was defined as stone free or complete fragmentation after 1 or 2 sessions of SWL. The impact of patients age, sex, body mass index, stone laterality, location, volume, length, mean SMC and SMD, HU and Hounsfield density (HD), skin to stone distance (SSD) and number of shock waves were evaluated by univariate and multivariate analysis. Only 76 patients were available for follow-up. Success of disintegration was observed in 50 out of 76 patients (65.8 %). On multivariate analysis, SMC and number of shock wave were the significant independent factors affecting SWL outcome (p = 0.04 and p = 0.000, respectively). SMC as detected by DXA is a significant predictor of success of stone disintegration by SWL. SMC measured by DXA is more accurate than HU measured by CT. Patients with high stone mineral content (SMC greater than 0.65 g) should be directly offered another treatment option.

  10. A general framework and review of scatter correction methods in x-ray cone-beam computerized tomography. Part 1: Scatter compensation approaches

    Energy Technology Data Exchange (ETDEWEB)

    Ruehrnschopf, Ernst-Peter; Klingenbeck, Klaus [Siemens AG, Healthcare Sector, Imaging and Therapy Division, Forchheim (Germany)

    2011-07-15

    Since scattered radiation in cone-beam volume CT implies severe degradation of CT images by quantification errors, artifacts, and noise increase, scatter suppression is one of the main issues related to image quality in CBCT imaging. The aim of this review is to structurize the variety of scatter suppression methods, to analyze the common structure, and to develop a general framework for scatter correction procedures. In general, scatter suppression combines hardware techniques of scatter rejection and software methods of scatter correction. The authors emphasize that scatter correction procedures consist of the main components scatter estimation (by measurement or mathematical modeling) and scatter compensation (deterministic or statistical methods). The framework comprises most scatter correction approaches and its validity also goes beyond transmission CT. Before the advent of cone-beam CT, a lot of papers on scatter correction approaches in x-ray radiography, mammography, emission tomography, and in Megavolt CT had been published. The opportunity to avail from research in those other fields of medical imaging has not yet been sufficiently exploited. Therefore additional references are included when ever it seems pertinent. Scatter estimation and scatter compensation are typically intertwined in iterative procedures. It makes sense to recognize iterative approaches in the light of the concept of self-consistency. The importance of incorporating scatter compensation approaches into a statistical framework for noise minimization has to be underscored. Signal and noise propagation analysis is presented. A main result is the preservation of differential-signal-to-noise-ratio (dSNR) in CT projection data by ideal scatter correction. The objective of scatter compensation methods is the restoration of quantitative accuracy and a balance between low-contrast restoration and noise reduction. In a synopsis section, the different deterministic and statistical methods are

  11. Bilateral filtering using the full noise covariance matrix applied to x-ray phase-contrast computed tomography

    Science.gov (United States)

    Allner, S.; Koehler, T.; Fehringer, A.; Birnbacher, L.; Willner, M.; Pfeiffer, F.; Noël, P. B.

    2016-05-01

    The purpose of this work is to develop an image-based de-noising algorithm that exploits complementary information and noise statistics from multi-modal images, as they emerge in x-ray tomography techniques, for instance grating-based phase-contrast CT and spectral CT. Among the noise reduction methods, image-based de-noising is one popular approach and the so-called bilateral filter is a well known algorithm for edge-preserving filtering. We developed a generalization of the bilateral filter for the case where the imaging system provides two or more perfectly aligned images. The proposed generalization is statistically motivated and takes the full second order noise statistics of these images into account. In particular, it includes a noise correlation between the images and spatial noise correlation within the same image. The novel generalized three-dimensional bilateral filter is applied to the attenuation and phase images created with filtered backprojection reconstructions from grating-based phase-contrast tomography. In comparison to established bilateral filters, we obtain improved noise reduction and at the same time a better preservation of edges in the images on the examples of a simulated soft-tissue phantom, a human cerebellum and a human artery sample. The applied full noise covariance is determined via cross-correlation of the image noise. The filter results yield an improved feature recovery based on enhanced noise suppression and edge preservation as shown here on the example of attenuation and phase images captured with grating-based phase-contrast computed tomography. This is supported by quantitative image analysis. Without being bound to phase-contrast imaging, this generalized filter is applicable to any kind of noise-afflicted image data with or without noise correlation. Therefore, it can be utilized in various imaging applications and fields.

  12. Bilateral filtering using the full noise covariance matrix applied to x-ray phase-contrast computed tomography.

    Science.gov (United States)

    Allner, S; Koehler, T; Fehringer, A; Birnbacher, L; Willner, M; Pfeiffer, F; Noël, P B

    2016-05-21

    The purpose of this work is to develop an image-based de-noising algorithm that exploits complementary information and noise statistics from multi-modal images, as they emerge in x-ray tomography techniques, for instance grating-based phase-contrast CT and spectral CT. Among the noise reduction methods, image-based de-noising is one popular approach and the so-called bilateral filter is a well known algorithm for edge-preserving filtering. We developed a generalization of the bilateral filter for the case where the imaging system provides two or more perfectly aligned images. The proposed generalization is statistically motivated and takes the full second order noise statistics of these images into account. In particular, it includes a noise correlation between the images and spatial noise correlation within the same image. The novel generalized three-dimensional bilateral filter is applied to the attenuation and phase images created with filtered backprojection reconstructions from grating-based phase-contrast tomography. In comparison to established bilateral filters, we obtain improved noise reduction and at the same time a better preservation of edges in the images on the examples of a simulated soft-tissue phantom, a human cerebellum and a human artery sample. The applied full noise covariance is determined via cross-correlation of the image noise. The filter results yield an improved feature recovery based on enhanced noise suppression and edge preservation as shown here on the example of attenuation and phase images captured with grating-based phase-contrast computed tomography. This is supported by quantitative image analysis. Without being bound to phase-contrast imaging, this generalized filter is applicable to any kind of noise-afflicted image data with or without noise correlation. Therefore, it can be utilized in various imaging applications and fields.

  13. Prognostic Contribution of Exercise Capacity, Heart Rate Recovery, Chronotropic Incompetence, and Myocardial Perfusion Single-Photon Emission Computerized Tomography in the Prediction of Cardiac Death and All-Cause Mortality.

    Science.gov (United States)

    Arbit, Boris; Azarbal, Babak; Hayes, Sean W; Gransar, Heidi; Germano, Guido; Friedman, John D; Thomson, Louise; Berman, Daniel S

    2015-12-01

    Chronotropic incompetence, measured by the percentage (%) of heart rate (HR) reserve achieved (%HR reserve), abnormal HR recovery, reduced exercise capacity (EC), and myocardial perfusion single-photon emission computerized tomography (SPECT MPS) abnormalities are known predictors of all-cause mortality (ACM) and cardiac death (CD). The aim of this study was to determine if EC, %HR reserve, and HR recovery add incremental value to MPS in the prediction of ACM and CD. A total of 11,218 patients without valvular disease and not on β blockers underwent symptom-limited exercise MPS. %HR reserve was (peak HR - rest HR)/(220 - age - rest HR) × 100, with %HR reserve recovery was peak HR - recovery HR. An HR recovery recovery, χ(2) = 18.45; diabetes, χ(2) = 17.75; and previous coronary artery disease, χ(2) = 11.85 (p ≤0.0006). The independent predictors of CD were SSS, χ(2) = 54.25; EC, χ(2) = 49.34; age, χ(2) = 46.45; abnormal electrocardiogram at rest, χ(2) = 30.60; previous coronary artery disease, χ(2) = 20.69; Duke treadmill score, χ(2) = 19.50; %HR reserve, χ(2) = 11.43; diabetes, χ(2) = 10.23 (all p ≤0.0014); and HR recovery, χ(2) = 5.30 (p = 0.0214). The exercise variables showed increases in Harrell's C static and net improvement reclassification, with EC showing the strongest incremental improvement in predicting ACM and CD (respective C-index 76.5% and 83.3% and net reclassification index 0.3201 and 0.4996). In conclusion, EC, %HR reserve, and HR recovery are independent predictors of ACM and CD and add incremental prognostic value to extent and severity of MPS.

  14. A randomized double-blind placebo-controlled trial to investigate the effects of nasal calcitonin on bone microarchitecture measured by high-resolution peripheral quantitative computerized tomography in postmenopausal women — Study protocol

    Directory of Open Access Journals (Sweden)

    Azria Moise

    2008-04-01

    Full Text Available Abstract Background Bone microarchitecture is a significant determinant of bone strength. So far, the assessment of bone microarchitecture has required bone biopsies, limiting its utilization in clinical practice to one single skeletal site. With the advance of high-resolution imaging techniques, non-invasive in vivo measurement of bone microarchitecture has recently become possible. This provides an opportunity to efficiently assess the effects of anti-osteoporotic therapies on bone microarchitecture. We therefore designed a protocol to investigate the effects of nasal salmon calcitonin, an inhibitor of osteoclast activity, on bone microarchitecture in postmenopausal women, comparing weight bearing and non-weight bearing skeletal sites. Methods One hundred postmenopausal women will be included in a randomized, placebo-controlled, double-blind trial comparing the effect of nasal salmon calcitonin (200 UI/day to placebo over two years. Bone microarchitecture at the distal radius and distal tibia will be determined yearly by high-resolution peripheral quantitative computerized tomography (p-QCT with a voxel size of 82 μm and an irradiation of less than 5 μSv. Serum markers of bone resorption and bone formation will be measured every 6 months. Safety and compliance will be assessed. Primary endpoint is the change in bone microarchitecture; secondary endpoint is the change in markers of bone turnover. Hypothesis The present study should provide new information on the mode of action of nasal calcitonin. We hypothezise that - compared to placebo - calcitonin impacts on microstructural parameters, with a possible difference between weight bearing and non-weight bearing bones. Trial Registration ClinicalTrials.gov NCT00372099

  15. Evaluation of Jumping and Creeping Regularization Approaches Applied to 3D Seismic Tomography

    Science.gov (United States)

    Liu, M.; Ramachandran, K.

    2011-12-01

    Regularization deals with the ill-posedness of the inverse problem. The under-determined part of the problem is controlled by providing a priori knowledge on the physical solution in the form of additional constraints that the solution must satisfy. The final model is constrained to fit the data and also to satisfy some additional property. In seismic tomography, this property is selected such that the final model is as smooth as possible. This concept is physically meaningful as smooth models are sought that include only structure that is required to fit the data according to its uncertainty. The motivation for seeking a smooth model is that features present in the model should be essential to match the observations. Such a class of models is referred to as minimum structure models. The amount of structure in the estimated model parameters is measured in terms of roughness. In seismic tomography, second spatial derivatives are generally employed to quantify the model roughness. In this kind of regularized inversion, an objective function is minimized which includes norms that measure model roughness and data misfit. A tradeoff parameter is selected that provides the model with the least structure for a given level of data misfit. The regularized inverse problem that solves for model perturbation and also constrains perturbation flatness or smoothness during the inversion is known as creeping approach. The disadvantage of the creeping approach is that the final model will have no special properties and will be just a sum of smooth deviations added to the starting model. The regularized inverse problem that solves for model perturbation and also constrains model properties during the inversion is known as creeping approach. In the jumping approach, the final model can be constructed to have properties such as flatness or smoothness, since the regularization implements smoothing constraints on the model and not on the perturbation. The jumping and creeping approaches

  16. Doppler optical coherence microscopy and tomography applied to inner ear mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Page, Scott; Freeman, Dennis M. [Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts (United States); Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts (United States); Ghaffari, Roozbeh [Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts (United States)

    2015-12-31

    While it is clear that cochlear traveling waves underlie the extraordinary sensitivity, frequency selectivity, and dynamic range of mammalian hearing, the underlying micromechanical mechanisms remain unresolved. Recent advances in low coherence measurement techniques show promise over traditional laser Doppler vibrometry and video microscopy, which are limited by low reflectivities of cochlear structures and restricted optical access. Doppler optical coherence tomography (DOCT) and Doppler optical coherence microscopy (DOCM) both utilize a broadband source to limit constructive interference of scattered light to a small axial depth called a coherence gate. The coherence gate can be swept axially to image and measure sub-nanometer motions of cochlear structures throughout the cochlear partition. The coherence gate of DOCT is generally narrower than the confocal gate of the focusing optics, enabling increased axial resolution (typically 15 μm) within optical sections of the cochlear partition. DOCM, frequently implemented in the time domain, centers the coherence gate on the focal plane, achieving enhanced lateral and axial resolution when the confocal gate is narrower than the coherence gate. We compare these two complementary systems and demonstrate their utility in studying cellular and micromechanical mechanisms involved in mammalian hearing.

  17. X-ray micro-beam techniques and phase contrast tomography applied to biomaterials

    Science.gov (United States)

    Fratini, Michela; Campi, Gaetano; Bukreeva, Inna; Pelliccia, Daniele; Burghammer, Manfred; Tromba, Giuliana; Cancedda, Ranieri; Mastrogiacomo, Maddalena; Cedola, Alessia

    2015-12-01

    A deeper comprehension of the biomineralization (BM) process is at the basis of tissue engineering and regenerative medicine developments. Several in-vivo and in-vitro studies were dedicated to this purpose via the application of 2D and 3D diagnostic techniques. Here, we develop a new methodology, based on different complementary experimental techniques (X-ray phase contrast tomography, micro-X-ray diffraction and micro-X-ray fluorescence scanning technique) coupled to new analytical tools. A qualitative and quantitative structural investigation, from the atomic to the micrometric length scale, is obtained for engineered bone tissues. The high spatial resolution achieved by X-ray scanning techniques allows us to monitor the bone formation at the first-formed mineral deposit at the organic-mineral interface within a porous scaffold. This work aims at providing a full comprehension of the morphology and functionality of the biomineralization process, which is of key importance for developing new drugs for preventing and healing bone diseases and for the development of bio-inspired materials.

  18. X-ray micro-beam techniques and phase contrast tomography applied to biomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Fratini, Michela, E-mail: michela.fratini@gmail.com [Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, 00184 Roma (Italy); Dipartimento di Scienze, Università di Roma Tre, 00144 Roma (Italy); Campi, Gaetano [Institute of Crystallography, CNR, 00015 Monterotondo, Roma (Italy); Bukreeva, Inna [CNR NANOTEC-Institute of Nanotechnology, 00195 Roma (Italy); P.N. Lebedev Physical Institute RAS, 119991 Moscow (Russian Federation); Pelliccia, Daniele [School of Physics, Monash University, Victoria 3800 (Australia); Burghammer, Manfred [ESRF-The European Synchrotron, 3800 Grenoble (France); Tromba, Giuliana [Sincrotrone Trieste SCpA, 34149 Basovizza, Trieste (Italy); Cancedda, Ranieri; Mastrogiacomo, Maddalena [Dipartimento di Medicina Sperimentale dell’Università di Genova & AUO San Martino-IST Istituto Nazionale per la Ricerca sul Cancro, 16132 Genova (Italy); Cedola, Alessia [CNR NANOTEC-Institute of Nanotechnology, 00195 Roma (Italy)

    2015-12-01

    A deeper comprehension of the biomineralization (BM) process is at the basis of tissue engineering and regenerative medicine developments. Several in-vivo and in-vitro studies were dedicated to this purpose via the application of 2D and 3D diagnostic techniques. Here, we develop a new methodology, based on different complementary experimental techniques (X-ray phase contrast tomography, micro-X-ray diffraction and micro-X-ray fluorescence scanning technique) coupled to new analytical tools. A qualitative and quantitative structural investigation, from the atomic to the micrometric length scale, is obtained for engineered bone tissues. The high spatial resolution achieved by X-ray scanning techniques allows us to monitor the bone formation at the first-formed mineral deposit at the organic–mineral interface within a porous scaffold. This work aims at providing a full comprehension of the morphology and functionality of the biomineralization process, which is of key importance for developing new drugs for preventing and healing bone diseases and for the development of bio-inspired materials.

  19. Optical coherence tomography applied to the evaluation of wear of composite resin for posterior teeth

    Science.gov (United States)

    Mota, Cláudia C. B. O.; Guerra, Bruna A.; Machado, Brena S. A.; Cabral, Adolfo J.; Gomes, Anderson S. L.

    2015-06-01

    Resin composites are widely used as restorative materials due to their excellent aesthetical and mechanical properties. Posterior teeth are constantly submitted to occlusal stress and upon restoration require more resistant resins. The aim of this study was to analyze in vitro the wear suffered over time by restorations in resin composite in posterior teeth, by Optical Coherence Tomography (OCT). 30 molars had occlusal cavities prepared and were randomly divided into three groups (n=10) and restored with resin composite: G1: Filtek P90 (3M/ESPE), G2: Tetric N-Ceram (Ivoclar Vivadent); G3: Filtek P60 (3M/ESPE). Specimens were subjected to initial analysis by OCT (OCP930SR, Thorlabs, axial resolution 6.2 μm) and stereoscopic microscope. Specimens were submitted to thermocycling (500 cycles, 5-55 °C) and subjected to simulated wear through a machine chewing movements (Wear Machine WM001), projecting four years of use. After mechanical cycles, the specimens were submitted to a second evaluation by the OCT and stereoscopic microscopy. As a result, it was observed that 90% of the restorations of both groups had fractures and/or points of stress concentration, considered niches for early dissemination of new fracture lines. It was also found that G1 and G2 had more points of stress concentration, whereas G3 had a higher incidence of fracture lines already propagated. It was concluded that the G3 showed more brittle behavior at the masticatory wear when compared to G1 and G2.

  20. Innovations in Computerized Assessment.

    Science.gov (United States)

    Drasgow, Fritz, Ed.; Olson-Buchanan, Julie B., Ed.

    Chapters in this book present the challenges and dilemmas faced by researchers as they created new computerized assessments, focusing on issues addressed in developing, scoring, and administering the assessments. Chapters are: (1) "Beyond Bells and Whistles; An Introduction to Computerized Assessment" (Julie B. Olson-Buchanan and Fritz Drasgow);…

  1. HUMAN RELIABILITY ANALYSIS FOR COMPUTERIZED PROCEDURES

    Energy Technology Data Exchange (ETDEWEB)

    Ronald L. Boring; David I. Gertman; Katya Le Blanc

    2011-09-01

    This paper provides a characterization of human reliability analysis (HRA) issues for computerized procedures in nuclear power plant control rooms. It is beyond the scope of this paper to propose a new HRA approach or to recommend specific methods or refinements to those methods. Rather, this paper provides a review of HRA as applied to traditional paper-based procedures, followed by a discussion of what specific factors should additionally be considered in HRAs for computerized procedures. Performance shaping factors and failure modes unique to computerized procedures are highlighted. Since there is no definitive guide to HRA for paper-based procedures, this paper also serves to clarify the existing guidance on paper-based procedures before delving into the unique aspects of computerized procedures.

  2. Computerized tomography studies on schizophrenic diseases

    Energy Technology Data Exchange (ETDEWEB)

    Gross, G.; Huber, G.; Schuettler, R.

    1982-01-01

    Earlier clinical pneumoencephalographic studies showed a subgroup of schizophrenics that have small and dysplastic cerebral ventricles as well as a subgroup with a 'pure defect', i.e., a slight internal brain atrophy. In echoencephalograms of pure and mixed residual schizophrenic syndrome patients, a significantly higher average transverse diameter of the third ventricle was demonstrated compared to that in patients with complete remissions. Correlations cannot be expected between certain groups of disease, e.g., epilepsy, multiple sclerosis, or schizophrenia on the whole, and pneumoencephalographic (PEG) and CT findings. Only schizophrenics with distinct signs of pure defect that had persisted for at least 3 years revealed deviations from normal by CT and PEG, but those with irreversible fixed deformations of personality structure did not. In patients who were 50 years of age or less with psychic reactive and psychopathic personality disorders, CT showed an average third ventricle diameter of 4.2 mm (range 2-6 mm). Of 117 schizophrenics (average age 35.5 years), only 28% revealed pathological CT changes. However, of 36 schizophrenics with pure residual syndromes 69% showed pathological CT findings that always concerned the third ventricle, rarely the lateral ventricles, and in no case the cortex. The average transverse diameter of the third ventricle in this subgroup with pure defect was 7.6 mm, as compared to 4.6 mm in the subgroup of schizophrenics with complete remission. There was no increase in size with increasing years until the 50th year in schizophrenics, as well as in the control group of variations of psychic being (neuroses and psychopathic personality disorders).

  3. Effects of reusing baseline volumes of interest by applying (non-rigid image registration on positron emission tomography response assessments.

    Directory of Open Access Journals (Sweden)

    Floris H P van Velden

    Full Text Available OBJECTIVES: Reusing baseline volumes of interest (VOI by applying non-rigid and to some extent (local rigid image registration showed good test-retest variability similar to delineating VOI on both scans individually. The aim of the present study was to compare response assessments and classifications based on various types of image registration with those based on (semi-automatic tumour delineation. METHODS: Baseline (n = 13, early (n = 12 and late (n = 9 response (after one and three cycles of treatment, respectively whole body [(18F]fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (PET/CT scans were acquired in subjects with advanced gastrointestinal malignancies. Lesions were identified for early and late response scans. VOI were drawn independently on all scans using an adaptive 50% threshold method (A50. In addition, various types of (non-rigid image registration were applied to PET and/or CT images, after which baseline VOI were projected onto response scans. Response was classified using PET Response Criteria in Solid Tumors for maximum standardized uptake value (SUV(max, average SUV (SUV(mean, peak SUV (SUV(peak, metabolically active tumour volume (MATV, total lesion glycolysis (TLG and the area under a cumulative SUV-volume histogram curve (AUC. RESULTS: Non-rigid PET-based registration and non-rigid CT-based registration followed by non-rigid PET-based registration (CTPET did not show differences in response classifications compared to A50 for SUV(max and SUV(peak, however, differences were observed for MATV, SUV(mean, TLG and AUC. For the latter, these registrations demonstrated a poorer performance for small lung lesions (<2.8 ml, whereas A50 showed a poorer performance when another area with high uptake was close to the target lesion. All methods were affected by lesions with very heterogeneous tracer uptake. CONCLUSIONS: Non-rigid PET- and CTPET-based image registrations may be used to classify response

  4. High-resolution electrical resistivity tomography applied to patterned ground, Wedel Jarlsberg Land, south-west Spitsbergen

    Directory of Open Access Journals (Sweden)

    Marek Kasprzak

    2015-06-01

    Full Text Available This article presents results of two-dimensional electrical resistivity tomography (ERT applied to three types of patterned ground in Wedel-Jarlsberg Land (Svalbard, carried out in late July 2012. The structures investigated include sorted circles, non-sorted polygons and a net with sorted coarser material. ERT was used to recognize the internal ground structure, the shape of permafrost table below the active layer and the geometric relationships between permafrost, ground layering and surface patterns. Results of inversion modelling indicate that the permafrost table occurs at a depth of 0.5–1 m in a mountain valley and 1–2.5 m on raised marine terraces. The permafrost table was nearly planar beneath non-sorted deposits and wavy beneath sorted materials. The mutual relationships between the permafrost table and the shape of a stone circle are different from those typically presented in literature. Ground structure beneath the net with sorted coarser materials is complex as implied in convective models. In non-sorted polygons, the imaging failed to reveal vertical structures between them.

  5. Clinical study of computerized tomography for diagnosis of endometriosis of abdominal wall%CT对腹壁子宫内膜异位症诊断的临床研究

    Institute of Scientific and Technical Information of China (English)

    杜全兴; 张振全; 鲍瑞新

    2014-01-01

    目的:探讨CT对腹壁子宫内膜异位症的临床诊断价值。方法回顾性分析2011年6月至2013年12月,河北省玉田县医院收治的腹壁子宫内膜异位患者23例。通过术前的CT检查,辅助手术切除治疗。结果 CT扫描发现,本组23例患者,单个肿块14例,多个肿块9例。肿块最小0.9 cm ×1.6 cm,最大5.1 cm ×3.0 cm。肿块均位于腹壁切口瘢痕下方,位于皮下脂肪层12例,腹壁切口肌层内7例,肌层与壁层腹膜4例。实块型肿块3个,囊肿型肿块14个,囊实混合性6个。手术后23例患者症状基本消失。手术时间35~70 min,平均住院时间(6±2)d,预后较好,切口均甲级愈合。结论 CT对子宫内膜异位症的准确位置以及对周围组织的浸润情况具有较高的临床诊断价值,有助于子宫内膜异位症手术的顺利进行,值得临床推广。%Objective To investigate clinical diagnostic value of computerized tomography (CT) examination for endometriosis of abdominal wall.Methods A total of 23 patients with endometriosis of abdominal wall who were admitted to Hebei Yutian Hospital from June 201 1 to December 201 3,were enrolled into the retrospective analysis.All patients received perioperative CT scan,and then surgical resections were performed.Results The results of CT scan revealed that there were 1 4 cases of single mass and 9 cases of multiple masses in whole group (23 patients).The size of mass ranged from minimum of 0.9 cm ×1 .6 cm,to maximum of 5.1 cm ×3.0 cm.All masses were located below the abdominal wall wound scar,including 1 2 cases in the subcutaneous fat layer,7 cases in muscle layer of abdominal wall wound,and 7 cases between muscle and parietal peritoneum.Solid mass was observed in 3 cases,cystic mass in 1 4 cases,and mixed mass in 6 cases.The symptoms of all 23 patients almost disappeared after operation.The operation time was 35 to 70 minutes,and the average length of stay was (6 ±2

  6. High-resolution computerized tomography appearances of congenital malformations of the external and middle ear%先天性外中耳畸形的高分辨率CT表现

    Institute of Scientific and Technical Information of China (English)

    刘广保; 聂玉霞; 谭子琨

    2013-01-01

    Objective To evaluate the value of clinical application of high-resolution computerized tomography (HRCT) in the diagnose of congenital malformations of the external and middle ear.Methods The imaging data of 40 congenital malformations of the external and middle ear patients with HRCT were collected and analyzed retrospectively.All the temporal bones were scanned with HRCT.All images were targeted using high-bone-detail algorithms.Results 13 cases of external ear abnormalities were found,including 1 case of accessory auricle,1 case of accessory with stenosis of external acoustic meatus,3 cases of stenosis of external acoustic meatus,5 cases of externai auditory canal bony atresia and 3 cases of external auditoer canal atresia film,8 cases of middle ear abnormalities,17 cases of external and middle ear malformation,2 cases of external,middle and inner ear malformation.Conclusion External ear malformation and middle ear malformation are usually unilateral,while enlargement of vestibular aqueduct is bilateral.Congenital atresia of external acoustic meatus is the most common type in the external ear malformation.HRCT can provide clear images of temporal bone and auditory ossicles,which help us diagnose the malformations of external ear,middle ear and osseous labyrinth.%目的 探讨不同类型的先天性外中耳畸形的高分辨率CT(HRCT)的诊断价值.方法 收集诊断为先天性外中耳畸形患者40例的影像学资料进行回顾性研究,所有患者均行HRCT扫描,骨算法成像.结果 在本研究的40例先天性外中耳畸形患者中,单纯外耳畸形13例,其中副耳1例,副耳合并外耳道狭窄1例,外耳道狭窄3例,外耳道骨性闭锁5例,外耳道膜性闭锁3例,单纯中耳畸形8例,外耳并中耳畸形17例,外耳、中耳及内耳混合畸形2例.结论 外耳畸形及中耳畸形单侧发病常见,外耳、中耳畸形常同时发生.外耳畸形中先天性外耳道闭锁常见,中耳畸形以听骨链异常常见.HRCT对

  7. Application of ultrasonic computerized tomography to diagnosis of pile construction integrity%超声波层析成像在桩身结构完整性诊断中的应用

    Institute of Scientific and Technical Information of China (English)

    张永乐; 唐德高

    2009-01-01

    应用声波在桩身中传递的网格法射线追踪原理,采用逐次线性化迭代与带阻尼最小二乘QR分解相结合的超声层析成像方法进行图像重建.通过预设置缺陷的模型桩测试,对基于超声波速和特征阻抗的层析成像结果进行了分析验证.结果表明,超声层析成像技术应用于基桩完整性诊断中,可判定灌注桩桩身缺陷的位置和形状大小,并能达到较高的精度.特别是基于特征阻抗的层析成像,为基桩完整性的定量诊断提供了精确的数据平台,在基桩完整性诊断和对缺陷的工程处理方面具有较高的应用价值.%The article tries to cany out the image reconstruction of pile body based on the principle of ray tracing with grid, and by using the method of ultrasonic tomography, which combines successive linearization iteration with least square QR decomposition with damping. According to test results of model piles with defects to be pre-set, ultrasonic tomography method is used to analyze the ultrasonic velocity and its characteristic impedance. The results show that the ultrasonic tomography method can be applied to the integrity testing of pile foundation, and to identify the position, shape and size of defects of pile body in the cast-in-place pile. Moreover, it can reach the higher precision. Especially, for analyzing the characteristic impedance, it can provide the exact data for the quantitative testing of integrity of pile foundation. Therefore, it will have higher application value in the integrity testing of pile foundation and geoengineering treatment of defects.

  8. Graphical Models and Computerized Adaptive Testing.

    Science.gov (United States)

    Mislevy, Robert J.; Almond, Russell G.

    This paper synthesizes ideas from the fields of graphical modeling and education testing, particularly item response theory (IRT) applied to computerized adaptive testing (CAT). Graphical modeling can offer IRT a language for describing multifaceted skills and knowledge, and disentangling evidence from complex performances. IRT-CAT can offer…

  9. Nuclear magnetic resonance. Tomography of tomorrow

    Energy Technology Data Exchange (ETDEWEB)

    Ethier, R.; Melanson, D.; Peters, T.M. (Montreal Neurological Inst., Quebec (Canada))

    1983-10-01

    Ten years following computerized tomography, a new technique called nuclear magnetic resonance revolutionizes the field of diagnostic imaging. A major advantage of nuclear magnetic resonance is that the danger of radiation is non-existent as compared to computerized tomography. When parts of the human body are subject to radio-frequencies while in a fixed magnetic field, its most detailed structures are revealed. The quality of images, the applications, as well as the indications are forever increasing. Images obtained at the level of the brain and spinal cord through nuclear magnetic resonance supercede those obtained through computerized tomography. Hence, it is most likely that myelography, along with pneumoencephalography will be eliminated as a diagnostic means. It is without a doubt that nuclear magnetic resonance is tomorrow's computerized tomography.

  10. Computerizing the Library.

    Science.gov (United States)

    Chan, Jeanie; Whelan, Errol

    1988-01-01

    Discusses the development of a computerized high school library which uses CD-ROM optical storage systems. Describes hardware and software, setting up the system, preparing the online catalog, teaching information retrieval skills, and project evaluation. Notes prices of CD-ROM disks and equipment purchased. 4 references. (SV)

  11. Computerized Peer Assessment.

    Science.gov (United States)

    Davies, Phil

    2000-01-01

    Describes the introduction of a computerized peer assessment system as part of an undergraduate module in computer studies in the United Kingdom. Analyzes student responses to modification of the tutor-student relationship to a student-student relationship for assessment purposes, discusses plagiarism and the Web, and investigates effects on…

  12. Computerized Drug Information Services

    Science.gov (United States)

    And Others; Smith, Daniel R.

    1972-01-01

    To compare computerized services in chemistry, pharmacology, toxicology, and clinical medicine of pharmaceutical interest, equivalent profiles were run on magnetic tape files of CA-Condensates," CBAC," Excerpta Medica," MEDLARS" and Ringdoc." The results are tabulated for overlap of services, relative speed of citing references, and unique…

  13. A comparative study of high resolution cone beam X-ray tomography and synchrotron tomography applied to Fe- and Al-alloys.

    Science.gov (United States)

    Kastner, Johann; Harrer, Bernhard; Requena, Guillermo; Brunke, Oliver

    2010-10-01

    X-ray computed tomography (XCT) has become a very important method for non-destructive 3D-characterization and evaluation of materials. Due to measurement speed and quality, XCT systems with cone beam geometry and matrix detectors have gained general acceptance. Continuous improvements in the quality and performance of X-ray tubes and XCT devices have led to cone beam CT systems that can now achieve spatial resolutions down to 1 μm and even below. However, the polychromatic nature of the source, limited photon flux and cone beam artefacts mean that there are limits to the quality of the CT-data achievable; these limits are particularly pronounced with materials of higher density like metals. Synchrotron radiation offers significant advantages by its monochromatic and parallel beam of high brilliance. These advantages usually cause fewer artefacts, improved contrast and resolution.Tomography data of a steel sample and of two multi-phase Al-samples (AlSi12Ni1, AlMg5Si7) are recorded by advanced cone beam XCT-systems with a μ-focus (μXCT) and a sub-μm (nano-focus, sub-μXCT) X-ray source with voxel dimensions between 0.4 and 3.5 μm and are compared with synchrotron computed tomography (sXCT) with 0.3 μm/voxel. CT data features like beam hardening and ring artefacts, detection of details, sharpness, contrast, signal-to-noise ratio and the grey value histogram are systematically compared. In all cases μXCT displayed the lowest performance. Sub-μXCT gives excellent results in the detection of details, spatial and contrast resolution, which are comparable to synchrotron-XCT recordings. The signal-to-noise ratio is usually significantly lower for sub-μXCT compared with the two other methods. With regard to measurement costs "for industrial users", scanning volume, accessibility and user-friendliness sub-μXCT has significant advantages in comparison to synchrotron-XCT.

  14. A computerized TLD system

    Energy Technology Data Exchange (ETDEWEB)

    Pla, C.; Podgorsak, E.B.

    A computerized thermoluminescent (TL) readout technique is presented which considerably improves the precision of dose readout and facilitates the dose information management and storage. The technique is relatively simple and it involves an interface between a commercially available thermoluminescent dosimetry (TLD) analyzer and a minicomputer. Curve fitting, subtraction of unwanted thermogram peaks, background subtraction, studies of TL decay kinetics, and storage of large number of measured TL data are easily performed with the technique.

  15. Computerizing clinical practice guidelines

    DEFF Research Database (Denmark)

    Lyng, Karen Marie

    It is well described that hospitals have problems with sustaining high quality of care and expedient introduction of new medical knowledge. Clinical practice guidelines (CPGs) have been promoted as a remedy to deal with these problems. It is, however, also well described that application and comp......It is well described that hospitals have problems with sustaining high quality of care and expedient introduction of new medical knowledge. Clinical practice guidelines (CPGs) have been promoted as a remedy to deal with these problems. It is, however, also well described that application...... and compliance with CPGs in most areas of clinical practice are deficient. Computerization of CPGs has been brought forward as a method to disseminate and to support application of CPGs. Until now, CPG-computerization has focused on development of formal expressions of CPGs. The developed systems have, however......, not gained any extensive application in clinical practice. The basic assumption in this thesis is that the scanty penetration is due to an inappropriate design process when designing computerized CPGs for clinical work practice. This thesis examines the application of guidance within areas where CPG...

  16. The use of the Electrical Resistivity Tomography to image deep volcanic structures: a methodological study applied to Mt. Vesuvius (Italy).

    Science.gov (United States)

    Troiano, Antonio; Giulia Di Giuseppe, Maria; Somma, Renato; Brandi, Giuseppe; Troise, Claudia; De Natale, Giuseppe

    2016-04-01

    Geophysics is considered a powerful tool both for modeling the structure and controlling the dynamics of active volcanoes. In particular, the application of the electrical and electromagnetic (EM) methods is a topic of great interest, given the strong dependence of the electrical resistivity on the shallow and deep physical characteristics of a volcanic apparatus. Among the EM methods, the magnetotellurics (MT), reaching investigation depth ranging from a few hundred meters to tens of km, is the optimal tool to characterize the volcanic environments leading often to remarkable imaging of the buried structures. However, its dependence from a natural source make its application often difficult due to the presence of high noise levels. Moreover, MT curves are subjected to the so-called static shift effect, an anomalous displacement of the curves that cannot be modeled without some external constrain. Electrical Resistivity Tomography (ERT), on other hands, using an artificial source, ends in a more controlled imaging that is, however, often limited to the very shallow parts of the structures. The realization of a deeper ERT imaging is complicated by both physical and logistic reasons. The resolved depths depend from the intensity of the source, an electrical current injected into the ground, whereas the displacement of the measurements array often implies hard problems due to the nature of the volcanic environments. The actual progresses of the technologies offer some way to bypass the main limitation of the ERT technique. The use of new kind of measurement stations permits the realization of a sort of wireless electrodic arrays. The easiness of use of the actual power generators represents a further notable element. In conclusion, the ERT imaging could now represents an optimal tool also in the imaging of structures buried at intermediate depths (up to a few km). In such a way, also its interaction with the MT methods could results notably enhanced, due to the

  17. Multideimensional adaptive filtering for noise reduction in computerized tomography. Comparison and combination of convolution based and spline based approaches; Multidimensionale adaptive Filterung zur Rauschreduktion in der Computertomographie. Vergleich und Kombination faltungs- und splinebasierter Verfahren

    Energy Technology Data Exchange (ETDEWEB)

    Henke, Maria

    2009-07-01

    Since a few years there is the possibility of tomographic imaging with a C-Arm-system in addition to the conventional X-ray-computed tomography. By the use of a flatpanel detector the C-Arm-CT offers a high isotropic resolution. Besides the reduction of dose the improvement of image quality is on the top of the user's list of wishes. To improve the image quality at constant dose or allow dose reduction at changeless image quality methods of noise reduction are used in conventional CT-imaging. To reduce overall measurement- and reconstruction-time so-called on-line-compliant systems are developed which start reconstruction before the measurement is competed. The aim of this work is the development of algorithms for noise reduction in projection data which shall be applied especially to flatpanel-CT and fit in into online-compliant systems. Among the so far known noise reduction methods are the convolution based multidimensional adaptive filtering by Kachelries, Watzke and Kalender (MAF{sup KWK}) and the spline and statistic based filtering by La Riviere and Billmire (SSAF{sup RB}). The former can not be applied for on-line-reconstruction, the latter can be applied to one-dimensional data only. Both methods are developed further to overcome these restrictions. In addition a hybrid method from a combination of a convolution based and the spline and statistic approach is developed. The impact of the algorithms to noise and resolution is characterized using so-called {sigma}-FWHM-curves from simulated and measured one- and two-dimensional data, respectively. The change in noise impression and structure is considered by means of slices. Examples of the application to clinical data rounds out the comparison. The results of this work are a new convolution based adaptive filtering (CAF), which is on-line-compliant, a spline and statistic based filtering for two-dimensional data (SSAF{sup B2d}) and a hybrid method (Hybrid{sup CAF}). These new adaptive algorithms for

  18. Particle physics methodologies applied to time-of-flight positron emission tomography with silicon-photomultipliers and inorganic scintillators

    OpenAIRE

    Leming, Edward J

    2015-01-01

    Positron emission tomography, or PET, is a medical imaging technique which has been used in clinical environments for over two decades. With the advent of fast timing detectors and scintillating crystals, it is possible to envisage improvements to the technique\\ud with the inclusion of time-of-flight capabilities. In this context, silicon photomultipliers coupled to fast inorganic LYSO crystals are investigated as a possible technology choice. As part of the ENVISION collaboration a range of ...

  19. Resistivity and self-potential tomography applied to groundwater remediation and contaminant plumes: Sandbox and field experiments

    Science.gov (United States)

    Mao, D.; Revil, A.; Hort, R. D.; Munakata-Marr, J.; Atekwana, E. A.; Kulessa, B.

    2015-11-01

    Geophysical methods can be used to remotely characterize contaminated sites and monitor in situ enhanced remediation processes. We have conducted one sandbox experiment and one contaminated field investigation to show the robustness of electrical resistivity tomography and self-potential (SP) tomography for these applications. In the sandbox experiment, we injected permanganate in a trichloroethylene (TCE)-contaminated environment under a constant hydraulic gradient. Inverted resistivity tomograms are able to track the evolution of the permanganate plume in agreement with visual observations made on the side of the tank. Self-potential measurements were also performed at the surface of the sandbox using non-polarizing Ag-AgCl electrodes. These data were inverted to obtain the source density distribution with and without the resistivity information. A compact horizontal dipole source located at the front of the plume was obtained from the inversion of these self-potential data. This current dipole may be related to the redox reaction occurring between TCE and permanganate and the strong concentration gradient at the front of the plume. We demonstrate that time-lapse self-potential signals can be used to track the kinetics of an advecting oxidizer plume with acceptable accuracy and, if needed, in real time, but are unable to completely resolve the shape of the plume. In the field investigation, a 3D resistivity tomography is used to characterize an organic contaminant plume (resistive domain) and an overlying zone of solid waste materials (conductive domain). After removing the influence of the streaming potential, the identified source current density had a magnitude of 0.5 A m-2. The strong source current density may be attributed to charge movement between the neighboring zones that encourage abiotic and microbially enhanced reduction and oxidation reactions. In both cases, the self-potential source current density is located in the area of strong resistivity

  20. Computerized procedures system

    Science.gov (United States)

    Lipner, Melvin H.; Mundy, Roger A.; Franusich, Michael D.

    2010-10-12

    An online data driven computerized procedures system that guides an operator through a complex process facility's operating procedures. The system monitors plant data, processes the data and then, based upon this processing, presents the status of the current procedure step and/or substep to the operator. The system supports multiple users and a single procedure definition supports several interface formats that can be tailored to the individual user. Layered security controls access privileges and revisions are version controlled. The procedures run on a server that is platform independent of the user workstations that the server interfaces with and the user interface supports diverse procedural views.

  1. Evaluation of parapharyngeal space by computerized tomography and magnetic resonance. Part 1: anatomy; O valor da tomografia computadorizada e da ressonancia magnetica na avaliacao do espaco parafaringeo. Parte 1: anatomia

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Ricardo Pires de; Rapoport, Abrao [Hospital Heliopolis, Sao Paulo, SP (Brazil)

    1994-01-01

    The authors, through a comprehensive review of the literature, intend to establish an anatomical concept of the parapharyngeal space and its surroundings spaces in the supra-hyoid neck, based on its division by the fascial planes. The correlation between the anatomically defined parapharyngeal space and the findings of the sectional imaging procedures (computed tomography and magnetic resonance) is established, evidencing clear anatomic-radiologic correspondence. (author) 44 refs., 2 figs.

  2. Comportamento da sutura palatina mediana em crianças submetidas à expansão rápida da maxila: avaliação mediante imagem de tomografia computadorizada Behavior of the midpalatal suture in children submitted to rapid maxillary expansion: evaluation with computerized tomography

    Directory of Open Access Journals (Sweden)

    Omar Gabriel da Silva Filho

    2007-06-01

    Full Text Available OBJETIVO: o presente estudo, de caráter prospectivo, objetivou avaliar a imagem da sutura palatina mediana em crianças submetidas à expansão rápida da maxila por meio de tomografia computadorizada, após a fase de contenção. METODOLOGIA: a amostra constou de 17 crianças de ambos os gêneros, na faixa etária compreendida entre 5 anos e 2 meses e 10 anos e 5 meses no início do tratamento, provenientes da Clínica de Ortodontia Interceptiva da Sociedade de Promoção Social do Fissurado Lábio-Palatal da Universidade de São Paulo (PROFIS-USP, Bauru/SP. Tomografias computadorizadas foram implementadas para avaliar o comportamento da sutura palatina mediana em diferentes momentos do tratamento. RESULTADOS E CONCLUSÕES: constatou-se que, após um período médio de 8 a 9 meses de contenção com o aparelho expansor, a sutura palatina mediana mostrou-se completamente ossificada, desde a região da espinha nasal anterior até a espinha nasal posterior. Tal informação esclarece o comportamento da sutura palatina mediana frente à expansão rápida da maxila e reitera o senso comum quanto ao caráter biológico do procedimento.AIM: The aim of this prospective study was to evaluate the midpalatal suture in children submitted to rapid palatal expansion with computerized tomography. METHODS: The sample was comprised of 17 children aged between 5 years and 2 months and 10 years and 5 months, that were submited to rapid palatal expansion. The radiologic aspect of the sutures were evaluated through computerized tomography. RESULS AND CONCLUSIONS: The tomographic images showed that, after the retention phase (8 to 9 months post-expansion, the midpalatal suture was completely ossified from the anterior to the posterior nasal spine region.

  3. Computerized voiding diary.

    Science.gov (United States)

    Rabin, J M; McNett, J; Badlani, G H

    1993-01-01

    An electronic, computerized voiding diary, "Compu-Void" (patent pending) was developed in order to simplify, augment, and automate patients' recording of bladder symptomatology. A voiding diary as a tool has the potential to provide essential information for a more complete diagnostic and therefore therapeutic picture for each patient. Two major problems with the standard written voiding diary have been a lack of patient compliance and the limited amount of information it garners. Twenty-five women with various types of voiding dysfunctions were compared to twenty-five age and parity-matched control women in order to determine patient preferences of the Compu-Void when compared to the standard written voiding diary, compliance with each method, and amount and quality of information obtained with each method. Over 90% of subjects and over 70% of control group patients preferred the Compu-Void over the written diary (P Compu-Void exceeded that obtained with the written method.

  4. Computerizing natural history collections.

    Science.gov (United States)

    Sunderland, Mary E

    2013-09-01

    Computers are ubiquitous in the life sciences and are associated with many of the practical and conceptual changes that characterize biology's twentieth-century transformation. Yet comparatively little has been written about how scientists use computers. Despite this relative lack of scholarly attention, the claim that computers revolutionized the life sciences by making the impossible possible is widespread, and relatively unchallenged. How did the introduction of computers into research programs shape scientific practice? The Museum of Vertebrate Zoology (MVZ) at the University of California, Berkeley provides a tractable way into this under-examined question because it is possible to follow the computerization of data in the context of long-term research programs.

  5. Comparison among GPR measurements and ultrasonic tomographies with different inversion strategies applied to the basement of an ancient egyptian sculpture.

    Science.gov (United States)

    Sambuelli, Luigi; Bohm, Gualtiero; Capizzi, Patrizia; Cardarelli, Ettore; Cosentino, Pietro; D'Onofrio, Laurent; Marchisio, Mario

    2010-05-01

    By the late 2008 one of the most important pieces of the "Museo delle Antichità Egizie" in Turin, the sculpture of the Pharaoh with god Amun, was planned to be one of the masterpieces of a travelling exhibition in Japan. The "Fondazione Museo delle Antichità Egizie di Torino", managing the museum, was concerned with the integrity of the basement of the statue which actually presents visible signs of restorations dating back to the early IXX century. The questions put by the museum managers were to estimate the internal extension of some visible fractures, to search for unknown internal ones and to provide information about the overall mechanical strength of the basement. In order to tackle the first and second questions a GPR reflection survey of the basement along three sides was performed and the results were assembled in a 3D rendering. As far as the third question is concerned, two parallel, horizontal ultrasonic 2D tomographies across the basement were made with a source-receiver layout able to acquire, for each section, 723 ultrasonic signals correspondent to different transmitter and receiver positions. The ultrasonic tomographic data were inverted using different software based upon different algorithms. The obtained velocity images were then compared with the GPR results and with the visible joints on the basement. A critical analysis of the comparisons is finally presented.

  6. Computerized tomographic evaluation of cerebral cysticercosis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bo Young; Lee, Mi Sook; Jeon, Doo Sung; Kim, Hong Soo; Rhee, Hak Song [Precbyterian Medical Center, Chonju (Korea, Republic of)

    1988-08-15

    Cerebral cysticercosis, unfortunately frequent in Korea, is a parastic disease in which man serve as the intermediate host of taenia solium. The larvae have a predilection for the central nervous system and can cause a variety of neurologic symptoms. The authors reviewed 19 cases of surgically proven cerebral cysticercosis and following results were obtained. 1. The most frequent age distribution was 5th and 6th decade and male to female ratio was 14:5. 2. The most frevalent involving site was cerebral parenchyme and following by ventricles. 3. Clinical manifestations were symtom and sign of increased ICP, seizure and focal neurological dificit. 4. It was assumed that computerized tomography was the procedure of choice for the diagnosis of these parasitic brain disease.

  7. Preoperative staging of perforated diverticulitis by computed tomography scanning

    NARCIS (Netherlands)

    M.P.M. Gielens; I.M. Mulder (Irene); E. van der Harst (Erwin); M.P. Gosselink (Martijn Pieter); K.J. Kraal; H.T. Teng; J.F. Lange (Johan); J. Vermeulen (Jefrey)

    2012-01-01

    textabstractBackground: Treatment of perforated diverticulitis depends on disease severity classified according to Hinchey's preoperative classification. This study assessed the accuracy of preoperative staging of perforated diverticulitis by computerized tomography (CT) scanning. Methods: All patie

  8. Computerized molecular modeling of carbohydrates

    Science.gov (United States)

    Computerized molecular modleing continues to increase in capability and applicability to carbohydrates. This chapter covers nomenclature and conformational aspects of carbohydrates, perhaps of greater use to carbohydrate-inexperienced computational chemists. Its comments on various methods and studi...

  9. Proposal of recommendations for quality control in computerized tomography, with emphasis in new technologies; Proposta de um protocolo de controle de qualidade em tomografia computadorizada, com enfase nas novas tecnologias

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Marlon da Silva Brandao; Neves, Camila Nascimento das

    2016-11-01

    The use of computed tomography (CT) has continuously grown over the years and expanding its applications in different medical procedures. As a result, there was an increase of frequency and in collective dose. One of the strategies to maximize the benefits of this important imaging modality is the implementation of optimization of protection programs. As part of this process, a quality control should be established to ensure the correct performance of the scanner. Quality control protocols can be very useful to carry out all tests in a standard methodology and well-established tolerance values. However, to keep up with the constant advances in technology, these protocols must be constantly reviewed and updated to allow its application in different existing models. The objective of this work is to develop a quality control protocol based on international recommendations and in national standards. (author)

  10. On-line course as tools for radiation protection training in patients. A practical case in computerized tomography; El Aula Virtual como herramienta para la formacion en PR del paciente; caso practico en tomografia computarizada

    Energy Technology Data Exchange (ETDEWEB)

    Medina Campos, J.; Fernandez Tallon, J.; Busca Suau, J.; Baro Casanovas, J.

    2006-07-01

    The rise in ionizing radiation applications within the field of diagnostics, with the corresponding increase in both number and doses received by patients, requires adequate resources for education and training in radiological protection. In is quite difficult to assemble professionals at a specific place to carry out training. However, the use of Information and Communication Technologies (IT) makes it possible to carry out training. However, the use of Information and Communication Technologies (IT) makes it possible to carry out training through Internet in an effective, easy and amusing way (e-learning). An on-line course of patient radiological protection and quality control in computer tomography has been developed aimed at professionals that use these diagnostic techniques. The course has been run twice in the period 2005-2006. The course is found on an Internet-accessible Virtual Campus, which allows access to multimedia contents, communication between students and instructors and follow-up of students performance. Final evaluation is done on-line and successfully passing the course counts for 8.9 credits in the Continuous Education Programme of Spanish Health Systems. (Author)

  11. Evaluation of a new pencil-type ionization chamber for dosimetry in computerized tomography beams; Avaliacao de uma nova camara de ionizacao tipo lapis para dosimetria em feixes de tomografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Maysa C. de; Neves, Lucio P.; Silva, Natalia F. da; Santos, William de S.; Caldas, Linda V.E., E-mail: maysadecastro@gmail.com, E-mail: lpneves@ipen.br, E-mail: na.fiorini@gmail.com, E-mail: wssantos@ipen.br, E-mail: lcaldas@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2014-07-01

    For performing dosimetry in computed tomography beams (CT), use is made of a pencil-type ionization chamber, since this has a uniform response to this type of beam. The common commercial chambers in Brazil have a sensitive volume length of 10 cm. Several studies of prototypes of this type of ionization chamber have been conducted, using different materials and geometric configurations, in the Calibration Laboratory Instruments of the Institute of Nuclear and Energy Research (LCI) and these showed results within internationally acceptable limits. These ion chambers of 10 cm are widely used nowadays, however studies have revealed that they have underestimated the dose values. In order to solve this problem, we developed a chamber with sensitive volume length of 30 cm. As these are not yet very common and no study has yet been performed on LCI conditions on their behavior, is important that the characteristics of these dosemeters are known, and the influence of its various components. For your review, we will use the Monte Carlo code Penelope, freely distributed by the IAEA. This method has revealed results consistent with other codes. The results for this new prototype can be used in dosimetry of the CT of the hospitals and calibration laboratories as the LCI.

  12. Project, construction and test of a mini computerized tomograph

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira Junior, J.M. de [Universidade de Sorocaba (UNISO), SP (Brazil). Centro de Ciencias Exatas e Tecnologicas (CETEC)

    2003-06-01

    Computed Tomography (CT) refers to the cross-sectional imaging of an object from both transmission or reflection data collected by illuminating the object from many different directions. CT is an imaging technique that has revolutionized the field of medical diagnostics. There are many others applications for CT images, such as, nondestructive evaluation of industrial products and analysis of biological specimens. A mini computerized tomograph was projected, constructed and tested. It operates with a gamma ray source of {sup 241} Am (photons of 60 keV and 100 mCi of intensity) and a NaI(Tl) solid state detector. The system features translation and rotation scanning modes, a 100 mm effective field of view, and 1 mm spatial resolution. The preliminary results indicated a resolution between 5 % to 7 % to detect mass attenuation coefficient variations. The total cost of the Mini Computerized Tomograph of UNISO (MTCU) was about US$ 20.000,00. (author)

  13. Optimization of recommendations for abdomen computerized tomography based on reconstruction filters, voltage and tube current; Otimizacao de protocolos de tomografia computadorizada de abdome com base nos filtros de reconstrucao, tensao e corrente do tubo

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, Vinicius da Costa

    2015-07-01

    The use of computed tomography has increased significantly over the past decades. In Brazil the use increased more than twofold from 2008 to 2014, in the meantime the abdomen procedures have tripled. The high frequency of this procedure combined by the increasing collective radiation dose in medical exposures, has resulted development tools to maximize the benefit in CT images. This work aimed to establish protocols optimized in abdominal CT through acquisitions parameters and reconstructions techniques based on filters kernels. A sample of patients undergoing abdominal CT in a diagnostic center of Rio de Janeiro was assessed. Had been collected patients information and acquisitions parameters. The phantoms CT image acquisitions were performed by using different voltage values by adjusting the tube current (mAs) to obtain the same value from CTDI{sub vol} patients with normal BMI. Afterwards, the CTDIvol values were reduced by 30%, 50% and 60%. All images were reconstructed with low-contrast filters (A) and standard filters (B). The CTDIvol values for patients with normal BMI were 7% higher than in patients with underweight BMI and 30%, 50% and 60% lower than the overweight, obese I and III patients, respectively. The evaluations of image quality showed that variation of the current (mA) and the reconstruction filters did not affect the Hounsfield values. When the contrast-to-noise ratio (CNR) was normalized to CTDIvol, the protocols acquired with 60% reduction of CTDIvol with 140 kV and 80 kV showed CNR 6% lower than the routine. Modifications of the acquisition parameters did not affect spatial resolution, but the post-processing with B filters reduced the spatial frequency by 16%. With reduced the dose of 30%, lesions in the spleen had the CNR higher than 10% routine protocols with 140 kV acquired and post-processed to filter A. The image post-processing with a filter A with a 80kV voltage provided CNR values equal to the routine for the liver lesions with a 30

  14. Evaluation of standard and use tendency of image diagnosis exams in Brazil with emphasis in pediatric computerized tomography; Avaliacao do padrao e tendencia de uso de exames de diagnostico por imagem no Brasil com enfase em tomografia computadorizada pediatrica

    Energy Technology Data Exchange (ETDEWEB)

    Dovales, Ana Cristina Murta

    2016-07-01

    There is little information on developing countries about the use of diagnostic imaging procedures and the doses associated with radiological examinations. This study assessed the pattern and trend of diagnostic imaging usage in outpatients of the Brazilian Unified Health System (SUS) by modality and examined body part. Emphasis was given to computed tomography (CT) scans for which the analysis was extended to the private health care sector and included the evaluation of age at examination distribution, and dose estimation for children and young adults. Information on the use of diagnostic imaging procedures among SUS outpatients was obtained from the Outpatient Information System (SIA) of the Department of Information Technology of SUS (DATASUS). Data on the use of CT in the private health care sector were extracted from the Radiological Information Systems (RIS) of 25 private radiology services in 8 Brazilian cities. Effective doses and absorbed doses on organs of interest were estimated individually for 4,497 patients younger than 20 years of age using CT scan technical parameters and Monte Carlo simulations of radiation transport. Between 2002 and 2012 it was observed that conventional radiology was the most frequent modality of diagnostic imaging in SUS outpatients, but more sophisticated modalities, such as CT and magnetic resonance imaging, had the highest growth rates over the study period. The most frequent CT scan in SUS outpatients between 2001 and 2011 was the head/neck exam, but abdomen/pelvis examinations were the ones that grew the most. Patients up to 20 years of age made approximately 13% and 9% of the CT examinations between 2008 and 2014 in the public and private health care systems, respectively. About one-third of the private-sector patients had more than one CT scan in this period. There was great variation in doses, even for the same type of procedure in patients of the same age group. The highest mean effective dose was 13.5 mSv estimated

  15. Tuberculose pulmonar: achados na tomografia computadorizada de alta resolução do tórax em pacientes com doença em atividade comprovada bacteriologicamente Pulmonary tuberculosis: findings on high resolution computerized tomography of active disease on patients with bacteriological confirmation

    Directory of Open Access Journals (Sweden)

    CRISTIANE ALÓ CAMPOS

    2002-01-01

    Full Text Available Objetivo: Descrever os achados em pacientes com tuberculose pulmonar em atividade na tomografia computadorizada de alta resolução e o padrão de distribuição das lesões pelo parênquima pulmonar. Casuística e método: Foram analisadas retrospectivamente as tomografias de alta resolução de 42 pacientes com diagnóstico bacteriológico de tuberculose pulmonar ou forte suspeita clínica, com posterior confirmação bacteriológica. Resultados: Os principais sinais sugestivos de atividade encontrados foram nódulos do espaço aéreo (83%, nódulos centrolobulares (74%, aspecto de árvore em brotamento (67%, cavitações (67%, espessamento das paredes brônquicas (55%, consolidações (48%, opacidade em vidro fosco (21%, e espessamento do interstício pulmonar (9%. Conclusão: A tomografia computadorizada de alta resolução do tórax pode sugerir fortemente atividade da doença, sendo particularmente útil nos pacientes com baciloscopias negativas e/ou radiografias indeterminadas, permitindo a instituição de tratamento adequado, antes mesmo do crescimento da micobactéria em meio de cultura.Background: The aim of this study was to describe the signs of active tuberculosis in patients submitted to high resolution computerized tomography and the distribution of lesions along the pulmonary parenchyma. Material and methods: The high resolution CTs performed on 42 patients with tuberculosis either bacteriologically diagnosed or clinical suspected and later confirmed by bacteriological tests were studied. Results: The signs of disease activity observed were airspace nodule (83%, centrilobular nodule (74%, tree-in-bud pattern (67%, cavitations (67%, bronchial thickening (55%, parenchymal consolidations (48%, ground glass opacity (21% and thickening of the inter and intralobular septa (9%. Conclusion: High resolution computed tomography can be strongly suggestive of disease activity, is particularly helpful in patients with negative smear and

  16. Computerized proof techniques for undergraduates

    Science.gov (United States)

    Smith, Christopher J.; Tefera, Akalu; Zeleke, Aklilu

    2012-12-01

    The use of computer algebra systems such as Maple and Mathematica is becoming increasingly important and widespread in mathematics learning, teaching and research. In this article, we present computerized proof techniques of Gosper, Wilf-Zeilberger and Zeilberger that can be used for enhancing the teaching and learning of topics in discrete mathematics. We demonstrate by examples how one can use these computerized proof techniques to raise students' interests in the discovery and proof of mathematical identities and enhance their problem-solving skills.

  17. Analysis of rocket beacon transmissions for computerized reconstruction of ionospheric densities

    Science.gov (United States)

    Bernhardt, P. A.; Huba, J. D.; Chaturvedi, P. K.; Fulford, J. A.; Forsyth, P. A.; Anderson, D. N.; Zalesak, S. T.

    1993-08-01

    Three methods are described to obtain ionospheric electron densities from transionospheric, rocket-beacon TEC data. First, when the line-of-sight from a ground receiver to the rocket beacon is tangent to the flight trajectory, the electron concentration can be obtained by differentiating the TEC with respect to the distance to the rocket. A similar method may be used to obtain the electron-density profile if the layer is horizontally stratified. Second, TEC data obtained during chemical release experiments may be interpreted with the aid of physical models of the disturbed ionosphere to yield spatial maps of the modified regions. Third, computerized tomography (CT) can be used to analyze TEC data obtained along a chain of ground-based receivers aligned along the plane of the rocket trajectory. CT analysis of TEC data is used to reconstruct a 2D image of a simulated equatorial plume. TEC data is computed for a linear chain of nine receivers with adjacent spacings of either 100 or 200 km. The simulation data are analyzed to provide an F region reconstruction on a grid with 15 x 15 km pixels. Ionospheric rocket tomography may also be applied to rocket-assisted measurements of amplitude and phase scintillations and airglow intensities.

  18. Computerized sociometric assessment for preschool children

    NARCIS (Netherlands)

    Endedijk, H.M.; Cillessen, A.H.N.

    2015-01-01

    In preschool classes, sociometric peer ratings are used to measure children's peer relationships. The current study examined a computerized version of preschool sociometric ratings. The psychometric properties were compared of computerized sociometric ratings and traditional peer ratings for prescho

  19. Elementary representative sizes of soil attributes via attenuation of gamma rays and computerized tomography; Tamanhos elementares representativos de atributos do solo via atenuacao de raios gama e tomografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Borges, Jaqueline Aparecida Ribaski

    2015-07-01

    In this study, the Computed Tomography (CT) and gamma-ray attenuation (GRA) techniques were used in the investigation of representative sample sizes for attributes related to soil structure. First of all, the representative elementary length (REL) for experimental measurements of soil mass attenuation coefficient (μes), of samples from a sandy and a clayey soil, was analyzed. The study was conducted with two radioactive sources ({sup 241}Am and {sup 137}Cs), three collimators (2 - 4 mm diameters), and 14 thickness (x) samples (2-5 cm). From these analyzes, it was possible to identify an ideal thickness range for each of the studied sources (2-4 cm and 12-15 cm for the sources of {sup 241}Am and {sup 137}Cs, respectively). The application of such results in representative elementary area evaluations, in clayey soil clods via CT, indicated that experimental soil mass attenuation coefficient average values obtained for x>4 cm and source {sup 241}Am might induce the use of samples which are not large enough for soil bulk density evaluations. Subsequently, μCT images with a total volume of 39×39×33 mm{sup 3} and spatial resolution of 60 μm were used for macroporous system morphological characterization of a Rhodic Ferralsol with clayey texture, under no-till (NT) and conventional till (CT) systems. Attributes as macroporosity (MAP), number of macropores (NMAP), tortuosity (τ) and connectivity (C) of the pores were assessed. The C degree was estimated based on the Euler-Poincare characteristic (EPC). Once 3D images enable the study of these attributes in different sample volumes, the proposed study is ideal for the analysis of representative elementary volume (REV). Usually, the selection of subvolumes for REV analysis occurs concentrically to a small volume or in adjacent positions. Here, we introduced a new method for selecting the positions of subvolumes, which are randomly chosen within the total image volume (random selection). It was observed that higher

  20. Doppler Tomography

    CERN Document Server

    Marsh, T R

    2000-01-01

    I review the method of Doppler tomography which translates binary-star line profiles taken at a series of orbital phases into a distribution of emission over the binary. I begin with a discussion of the basic principles behind Doppler tomography, including a comparison of the relative merits of maximum entropy regularisation versus filtered back-projection for implementing the inversion. Following this I discuss the issue of noise in Doppler images and possible methods for coping with it. Then I move on to look at the results of Doppler Tomography applied to cataclysmic variable stars. Outstanding successes to date are the discovery of two-arm spiral shocks in cataclysmic variable accretion discs and the probing of the stream/magnetospheric interaction in magnetic cataclysmic variable stars. Doppler tomography has also told us much about the stream/disc interaction in non-magnetic systems and the irradiation of the secondary star in all systems. The latter indirectly reveals such effects as shadowing by the a...

  1. Computerized Systems: Centralized or Decentralized?

    Science.gov (United States)

    Seitz, Linda Ludington

    1985-01-01

    Computerized management information systems have long been used in business, and data integration and sophisticated programing now enable many businesses to decentralize their information operations. This approach has advantages and disadvantages that colleges and universities must weigh and plan for carefully. (MSE)

  2. Determination of radiation-induced DNA double-strand breaks for the biological dose monitoring in cardiac computerized tomography; Bestimmung von strahleninduzierten DNA-Doppelstrangbruechen zum Monitoring der biologischen Dosis in der Herz-Computertomographie

    Energy Technology Data Exchange (ETDEWEB)

    Wegener, Jasmin

    2013-11-12

    Background and aims: X-rays cause relevant DNA damage to cells. DNA double-strand breaks (DSBs) are considered to be the most biologically significant radiation induced DNA-lesions. Recently a sensitive immunofluorescence microscopic method was developed to quantify x-ray induced DSBs as nuclear foci, even after doses as used in computed tomography. The method is based on the phosphorylation of the histone variant H2AX after formation of DSBs and distinct foci representing DSBs can be visualised. The number of foci correlates well with the delivered radiation dose. The importance of cardiac CT has increased during the last years. The radiation exposure of cardiac CT is rather high compared to other radiologic diagnostic procedures and techniques for dose-reduction receive increasing attention. In this context the purpose of this study was to determine to what extent the γ-H2AX-based method is able to measure x-ray induced DSBs in patients undergoing cardiac CT. Furthermore the objective was to evaluate whether CT-induced DSBs correlate with exposure parameters (dose length product, DLP) and to assess the influence of the scan protocols on the biological radiation damage. Materials and methods: 32 patients undergoing coronary CT angiography either using a 64-slice (n = 5: SOMATOM Sensation 64 {sup registered}) or a dual-source CT scanner (n = 27: SOMATOM Definition {sup registered}) were included in the study. Venous blood samples were taken before and 0.5 h, 2.5 h, and 24 h after the CT scan. Additional venous blood samples obtained before CT were irradiated in-vitro at various radiation doses (10 mGy, 50 mGy, 100 mGy) to obtain reference values of foci. Lymphocytes were separated and incubated with a specific γ-H2AX primary and a fluorescent secondary antibody. The number of γ-H2AX-foci was quantified using a fluorescence microscope. Every distinct focus represents one DNA-DSB. The number of radiation-induced DSBs was calculated by subtracting the foci number

  3. Computerized history-taking as a tool to manage dyslipidemia.

    Science.gov (United States)

    Zakim, David; Fritz, Christine; Braun, Niko; Fritz, Peter; Alscher, M Dominik

    2010-11-12

    Validated guidelines to manage low-density lipoprotein (LDL)-cholesterol are utilized inconsistently or not at all even though their application lowers the incidence of coronary events. New approaches are needed, therefore, to implement these guidelines in everyday practice. We compared an automated method for applying The National Cholesterol Education Panel (NCEP) guidelines with results from routine care for managing LDL-cholesterol. The automated method comprised computerized history-taking and analysis of historical data without physician input. Results from routine care were determined for 213 unselected patients and compared with results from interviews of the same 213 patients by a computerized history-taking program. Data extracted from hospital charts showed that routine care typically did not collect sufficient information to stratify risk and assign treatment targets for LDL-cholesterol and that there were inconsistencies in identifying patients with normal or elevated levels of LDL-cholesterol in relation to risk. The computerized interview program outperformed routine care in collecting historical data relevant to stratifying risk, assigning treatment targets, and clarifying the presence of hypercholesterolemia relative to risk. Computerized history-taking coupled with automated analysis of the clinical data can outperform routine medical care in applying NCEP guidelines for stratifying risk and identifying patients with hypercholesterolemia in relation to risk.

  4. Laser induced breakdown spectroscopy (LIBS) applied to stratigrafic elemental analysis and optical coherence tomography (OCT) to damage determination of cultural heritage Brazilian coins

    Science.gov (United States)

    M. Amaral, Marcello; Raele, Marcus P.; Z. de Freitas, Anderson; Zahn, Guilherme S.; Samad, Ricardo E.; D. Vieira, Nilson, Jr.; G. Tarelho, Luiz V.

    2009-07-01

    This work presents a compositional characterization of 1939's Thousand "Réis" and 1945's One "Cruzeiro" Brazilian coins, forged on aluminum bronze alloy. The coins were irradiated by a Q-switched Nd:YAG laser with 4 ns pulse width and energy of 25mJ emitting at 1064nm reaching 3.1010Wcm-2 (assured condition for stoichiometric ablation), forming a plasma in a small fraction of the coin. Plasma emission was collected by an optical fiber system connected to an Echelle spectrometer. The capability of LIBS to remove small fraction of material was exploited and the coins were analyzed ablating layer by layer from patina to the bulk. The experimental conditions to assure reproductivity were determined by evaluation of three plasma paramethers: ionization temperature using Saha-Boltzmann plot, excitation temperature using Boltzmann plot, plasma density using Saha-Boltzmann plot and Stark broadening. The Calibration-Free LIBS technique was applied to both coins and the analytical determination of elemental composition was employed. In order to confirm the Edict Law elemental composition the results were corroborated by Neutron Activation Analysis (NAA). In both cases the results determined by CF-LIBS agreed to with the Edict Law and NAA determination. Besides the major components for the bronze alloy some other impurities were observed. Finally, in order to determine the coin damage made by the laser, the OCT (Optical Coherence Tomography) technique was used. After tree pulses of laser 54μg of coin material were removed reaching 120μm in depth.

  5. Are Pediatric Emergency Care Applied Research Network Rules (PECARN Sufficient for Computed Cranial Tomography Decision in Pediatric Patients with Mild Head Trauma?

    Directory of Open Access Journals (Sweden)

    Hasan Mansur Durgun

    2016-03-01

    Full Text Available Objective: In this study we aimed to investigate the ap­plicability of Pediatric Emergency Care Applied Research Network (PECARN rules for decision to perform computed cranial tomography (CCT in pediatric patients with minor head trauma (MHT. Methods: 317 pediatric patients who underwent CCT for mild head trauma were evaluated retrospectively. The pa­tients were classified in two groups according to PECARN rules: below 2 years old, above 2 years old and then, these patient groups were classified into two subgroups accord­ing to the compatibility with PECARN rules. The patients re­quiring CCT according to PECARN rules were classified as PECARN compatible (PECARN +, the patients who under­went CCT without the need of CCT according to PECARN were classified as PECARN incompatible (PECARN -. Results: Approximately 20% patients in PECARN (+ group had abnormalities leading to prolonged hospitalization and only 3.8% patients of PECARN (- group had abnormali­ties. However, none of PECARN (- group patients required follow-up longer than 48 hours in the hospital. The most common symptoms necessitate CCT in PECARN (+ group were scalp swelling, scalp hematoma and vomiting. In PE­CARN (- group the most common signs were cuts in the scalp and dermal abrasions. The incidence of fracture in CCT was significantly higher in PECARN (+ group. Conclusion: Because CCT poses serious radiation expo­sure, neurological examination and clinical follow-up should be preferred in the evaluation of children with MHT. In con­clusion, PECARN rules were sufficient for CCT decision in pediatric patients with MHT. J Clin Exp Invest 2016; 7 (1: 35-40

  6. Termination Criteria for Computerized Classification Testing

    Directory of Open Access Journals (Sweden)

    Nathan A. Thompson

    2011-02-01

    Full Text Available Computerized classification testing (CCT is an approach to designing tests with intelligent algorithms, similar to adaptive testing, but specifically designed for the purpose of classifying examinees into categories such as - pass- and - fail.- Like adaptive testing for point estimation of ability, the key component is the termination criterion, namely the algorithm that decides whether to classify the examinee and end the test or to continue and administer another item. This paper applies a newly suggested termination criterion, the generalized likelihood ratio (GLR, to CCT. It also explores the role of the indifference region in the specification of likelihood-ratio based termination criteria, comparing the GLR to the sequential probability ratio test. Results from simulation studies suggest that the GLR is always at least as efficient as existing methods.

  7. [Value of computerized axial tomography in cranio-cerebral injuries].

    Science.gov (United States)

    Vigouroux, R P; Baurand, C; Gomez, A; Legre, J; Regis, H; Debaene, A

    1976-01-01

    Since May 1975 was have been working in the field of C.A.T. and its application to study head injuries. We are presenting differents groups of patients studied by C.A.T. I. -- DATA OF C.A.T. IN THE CASES OF EMERGENCY AND IMMEDIATE POST-OPERATIVE FOLLOW-UP OF HEAD INJURIES A) EMERGENCY STATE As soon as the clinical state of an head injured patient was supposed to need an operation, C.A.T. was realized; so differents abnormal scanners may be observed: 1. epidural hematoma, 2. subdural hematoma, 3. intra-cerebral hematoma, 4. acute subdural hematoma or contusion. We must do some comments: -- The Emi-scanner is pre-eminent in showing the exact topography of the lesion : so, the flap is easier to realise. -- In most cases the Emi-scanner is easier to interpret than angiogram for example contusion and hematoma. We know the goods results in hematomas and the poors results in surgery of contusions. -- But the senior advantage of C.A.T. is to provide all the informations in the totality of skull content. Emi-scanner shows bilateral lesions, ipsilateral lesion. C.A.T. is pre-eminent in showing the presence of this two lesions, more accurately than senior methods of investigations, so C.A.T. permits emergency neurosurgical treatment. B) C.A.T. AND FOLLOW-UP Repeated studies at post-intervals can be accomplished without risk to the patient, thus making follow-up simpler and more effective to the neurosurgical attitude. C) POST-OPERATIVE CONTROL AND C.A.T. Post-operative complications are always hard to diagnosis. C.A.T. is painless, quick and safe, and easier to interpret than an angiogram. II -- SEQUELLAE STADE AND C.A.T. In this field certains advantages of C.A.T. are immediatly apparents. In most cases the C.A.T. is the best screening method. Patients carried out are: -- psychiatric troubles, -- post-traumatic epilepsy. The results are not reliable. There is no anatomical-clinical relation in most cases. Differents pictures are observed: -- asymetrical ventricle enlargment, -- global ventricule enlargment, -- partial cerebral atrophy. III -- DISCUSSION 1. We are at the beginning of our study. 2. This not always possible to obtain a C.A.T. in emergency for a head injury, especialy at night. 3. Patients investigated following head trauma are among the most difficult to study with C.A.T. These invididuals send to be restless and uncooperative. Numerous artefacts produced by patient motion may lead to erroneous negative or positive diagnosis, so general anesthesia is often helpful. It is hoped that as a more rapid scanners become available this problem will be obviated. The C.A.T. alone is not capable, to provide all the necessary date concerning head injury. The C.A.T. is, however, re-adjusting our total investigation (E.E.G., angiograms) philosophy and practice rather than replacing the standard neuroradiological technique, except, may be, with epidural hematoma.

  8. [Dynamic study of the distal radioulnar joint with computerized tomography].

    Science.gov (United States)

    Martelli, A; Zanlungo, M; Egitto, M G; Sibilla, L; Uggetti, C; Zappoli, F

    1996-05-01

    The authors describe a CT technique which allows the dynamic study of the inferior radioulnar joint. The examination consists of 4 CT slices, three of them acquired at the same level-i.e., the radioulnar joint- in the prone, intermediate and supine positions, respectively. The last slice is acquired, with the patient in the prone position, at the base of the styloid process where the triangular fibrocartilage is demonstrated. The distal radioulnar ligaments are not directly visible. Nineteen patients complaining of painfully impaired pronation and supination because of previous trauma (11 Colles fractures, 7 distortions and 1 Galeazzi lesion) were examined with this technique. In all patients, both wrists were studied to obtain normal parameters. The radioulnar joint was evaluated superimposing a draft on the dynamic images, which demonstrated that, in healthy limbs, during movement the ulnar epiphysis is always contained between two parallel lines drawn on the volar and dorsal surfaces of the radial epiphysis, respectively. It was also confirmed that supination is possible up to 110-135 degrees from the support plane. CT demonstrated different causes of impaired movements in the affected joints: in 12 cases some fibrous density tissue was seen at the ulnar epiphysis on the volar aspect and considered to be the evolution of a traumatic hematoma; 6 patients presented dorsal subluxation of the ulna during movement; finally, volar subluxation was detected only in one case. In 6 patients the triangular fibrocartilage was detached; in 1 patient an intraarticular fluid collection was demonstrated. In 3 patients CT detected no abnormalities. The fibrous tissue is responsible for impaired movements and causes the detached triangular fibrocartilage to shrink. The authors believe that this simple CT technique can yield useful pieces of information for accurate surgical planning.

  9. GEANT4 simulations for low energy proton computerized tomography

    Energy Technology Data Exchange (ETDEWEB)

    Milhoretto, Edney [Federal University of Technology-Parana, UTFPR, Av. Sete de Setembro 3165, Curitiba-PR (Brazil); Schelin, Hugo R. [Federal University of Technology-Parana, UTFPR, Av. Sete de Setembro 3165, Curitiba-PR (Brazil)], E-mail: schelin@utfpr.edu.br; Setti, Joao A.P.; Denyak, Valery; Paschuk, Sergei A. [Federal University of Technology-Parana, UTFPR, Av. Sete de Setembro 3165, Curitiba-PR (Brazil); Evseev, Ivan G.; Assis, Joaquim T. de; Yevseyeva, O. [Polytechnic Institute/UERJ, Rua Alberto Rangel s/n, N. Friburgo, RJ, Brazil 28630-050 (Brazil); Lopes, Ricardo T. [Nuclear Instr. Lab./COPPE/UFRJ, Av. Horacio Macedo 2030, Rio de Janeiro-RJ (Brazil); Vinagre Filho, Ubirajara M. [Institute of Nuclear Engineering-IEN/CNEN, Rua Helio de Almeida 75, Rio de Janeiro-RJ (Brazil)

    2010-04-15

    This work presents the recent results of computer simulations for the low energy proton beam tomographic scanner installed at the cyclotron CV-28 of IEN/CNEN. New computer simulations were performed in order to adjust the parameters of previous simulation within the first experimental results and to understand some specific effects that affected the form of the final proton energy spectra. To do this, the energy and angular spread of the initial proton beam were added, and the virtual phantom geometry was specified more accurately in relation to the real one. As a result, a more realistic view on the measurements was achieved.

  10. Computerized tomography of the eye; Computertomografie des Auges

    Energy Technology Data Exchange (ETDEWEB)

    Rauch, Maximilian; Greschus, Susanne [Universitaetsklinik Bonn (Germany). Radiologische Klinik

    2017-03-15

    CT findings at the eye are mostly incidental indication during head and neck examinations. A targeted CT of the eye is indicated for instance in the case of suspected bulb perforation or the search for intraocular foreign objects. The contribution is also discussing radiation protection issues.

  11. [Computerized tomography in the diagnosis of congenital heart disease].

    Science.gov (United States)

    Makarenko, V N; Iurpol'skaia, L A

    2009-01-01

    The aim of the work was to evaluate the possibility to use CT techniques (SCT and MRT) for the diagnosis of congenital heart disease. A total of 426 patient aged 0-54 years were examined (171 by MRT and 255 by SCT. SCT of the heart with bolus injection of a contrast medium was performed on an Evolution C-150 superfast tomograph in the step-scanning regime and prospective synchronization with ECG (slice thickness 1.5-3 mm). Fasting SCT was used to examine children in the first year of life during quiet (unforced) breathing. Contrast material (Omnipack-300, 350; Visipack-270, 320) was administered at a dose of 1.5-2.0 ml/ kg b.w. at 0.2-0.6 ml/s. MRT was performed using a conventional MR tomograph with a 1 T field and pulsed spin-echo sequences synchronized with ECG for obtaining the anatomic picture and gradient echo-signals (cine-MRT) for the assessment of functional parameters (slice thickness 4-7 mm). Babies were examined under medicamentous sedation. All images were treated and analysed using an Advantage Windows 2.0 workstation and a program package for heart image analysis. A rational procedure of CT and image analysis was developed in the course of the study. It provided data on the formation of all segments and intercommunications of the heart, mutual localization of its cavities and major vessels, permitted to perform morphometry of selected cardiac structures and detect anatomic defects. The informative and diagnostic value of methods for comprehensive evaluation of the heart and mediastinum in patients with congenital heart disease was assessed. Methods of choice for the diagnosis of abnormalities and follow-up of the patients in different periods after surgery were identified.

  12. Vector entropy imaging theory with application to computerized tomography

    Science.gov (United States)

    Wang, Yuanmei; Cheng, Jianping; Heng, Pheng Ann

    2002-07-01

    Medical imaging theory for x-ray CT and PET is based on image reconstruction from projections. In this paper a novel vector entropy imaging theory under the framework of multiple criteria decision making is presented. We also study the most frequently used image reconstruction methods, namely, least square, maximum entropy, and filtered back-projection methods under the framework of the single performance criterion optimization. Finally, we introduce some of the results obtained by various reconstruction algorithms using computer-generated noisy projection data from the Hoffman phantom and real CT scanner data. Comparison of the reconstructed images indicates that the vector entropy method gives the best in error (difference between the original phantom data and reconstruction), smoothness (suppression of noise), grey value resolution and is free of ghost images.

  13. Epidural haematoma: computerized tomography (CT) parameters in 19 patients.

    Science.gov (United States)

    Reider-Groswasser, I; Frishman, E; Razon, N

    1991-01-01

    Between the years 1984 to 1989, 624 urgent brain CT examinations were performed for head-trauma patients in the Tel-Aviv Medical Center. In 19 patients, epidural haematomas were diagnosed. Different radiological parameters were discussed such as homogeneity of the haematoma, midline shift, ventricular collapse, obliteration of the peri-mesencephalic cistern and the presence of additional brain damage.

  14. Análise do diâmetro transverso do processo odontoide com uso da tomografia computadorizada Análisis del diámetro transverso del proceso odontoides con uso de la tomografía computarizada Analysis of the transverse diameter in the odontoid process by computerized tomography

    Directory of Open Access Journals (Sweden)

    Fábio Kazuo Soejima

    2010-12-01

    ó diferencia estadísticamente significante entre los promedios del DT de la odontoides de hombres y mujeres. El promedio del DT en los hombres fue de 10,29 mm, y en las mujeres de 9,39 mm. CONCLUSIÓN: la tomografía computarizada se mostró útil para la medición del diámetro transverso del proceso odontoides. La fijación con un tornillo cortical de 3,5 mm sería posible en todos los casos analizados y la fijación con dos tornillos sería posible en el 83,9% de los hombres y el 62,5% de las mujeres.INTRODUCTION: the reduced diameter of the odontoid is a challenge for the surgeon in preoperative planning and in choosing between the fixation of the fracture with one or two screws. OBJECTIVE: to analyze the transverse diameter (TD of the odontoid process by computerized tomography (CT for preoperative planning of osteosynthesis with one or two screws. METHODS: Seventy-nine cervical CT scans of adults without congenital malformations or complaints of pain in the upper cervical spine, treated at a private clinic in Blumenau - Santa Catarina, Brazil were analyzed. RESULTS: the mean age revealed no statistically significant difference between the sexes, but there was a statistically significant difference between the average TD of the odontoid of men and women. The TD average in men was of 10.29 mm, and in women it was of 9.39 mm. CONCLUSION: computerized tomography proved to be useful for measuring the odontoid process. The fixation with a 3.5 mm cortical screw would be possible in all examined cases, and the fixation with two screws would be possible in 83.9% of the men and 62.5% of the women.

  15. Computerized estimation of coal reserves of underground coal mines

    Energy Technology Data Exchange (ETDEWEB)

    Solymosi, F.; Kiss, J.

    1988-01-01

    No standardized methodology for long term planning exists in Hungary in the coal industry. A computerized method of coal reserve estimation based on normatives is described. The method has been applied in the Maza-South-Varalja-South region (Transdanubia, South Hungary). The applicability of the method is outlined and the error limit that was missing in coal reserve estimations is suggested to be introduced.

  16. Psychometric and psychological effects of review on computerized fixed and adaptive tests

    OpenAIRE

    Olea Díaz, Julio; Revuelta Menéndez, Javier; Ximénez, Carmen; Abad,Francisco José

    2000-01-01

    Two computerized versions of an English vocabulary test for Spanish speakers (an adaptive and a fixed one) were applied in a Spanish sample of first-year psychology undergraduate students. The effects of test type (computer-adaptive vs. computerized-fixed) and review condition (allowed vs. not allowed) on several psychological variables were examined. Withinsubject variables were measured both before and after review to study the effects of review on the psychological and psychometric variabl...

  17. A computerized track detector reader

    Energy Technology Data Exchange (ETDEWEB)

    Rosinski, S.W. (Centralne Lab. Ochrony Radiologicznej, Warsaw (Poland))

    1993-01-01

    The structure and basic operation function of a computerized facility named Track Detection Reader is described. This facility is used for recording, counting and evaluation of defects made by [alpha]-particles in a solid state detector. It consists of a microscope equipped with the movable stage, a TV screen and PC-AT computer. The microscope stage is being controlled by a stepper motor. The TV screen enables surface visualization of the detector analyzed while the PC-AT computer is being used for digital analysis of the detector surface, according to the functions of the program. (author). 4 refs, 3 figs.

  18. Interictal "patchy" regional cerebral blood flow patterns in migraine patients. A single photon emission computerized tomographic study

    DEFF Research Database (Denmark)

    Friberg, L; Olesen, J; Iversen, Helle Klingenberg

    1994-01-01

    In 92 migraine patients and 44 healthy control subjects we recorded regional cerebral blood flow (rCBF) with single photon emission computerized tomography and (133) Xe inhalation or with i.v. (99m) Tc-HMPAO. Migraine patients were studied interictally. A quantitated analysis of right...

  19. Computerized classification testing with the Rasch model

    NARCIS (Netherlands)

    Eggen, Theo J.H.M.

    2011-01-01

    If classification in a limited number of categories is the purpose of testing, computerized adaptive tests (CATs) with algorithms based on sequential statistical testing perform better than estimation-based CATs (e.g., Eggen & Straetmans, 2000). In these computerized classification tests (CCTs), the

  20. A First Life with Computerized Business Simulations

    Science.gov (United States)

    Thavikulwat, Precha

    2011-01-01

    The author discusses the theoretical lens, origins, and environment of his work on computerized business simulations. Key ideas that inform his work include the two dimensions (control and interaction) of computerized simulation, the two ways of representing a natural process (phenotypical and genotypical) in a simulation, which he defines as a…

  1. Computerizing primary schools in rural kenya

    DEFF Research Database (Denmark)

    Ogembo, J.G.; Ngugi, B.; Pelowski, Matthew John

    2012-01-01

    This paper investigates the outstanding challenges facing primary schools' computerization in rural Kenya. Computerization of schools is often envisaged as a 'magic', or at least a particularly efficient, solution to many of the problems that developing countries face in improving primary school...

  2. Resources for Improving Computerized Learning Environments.

    Science.gov (United States)

    Yeaman, Andrew R. J.

    1989-01-01

    Presents an annotated review of human factors literature that discusses computerized environments. Topics discussed include the application of office automation practices to educational environments; video display terminal (VDT) workstations; health and safety hazards; planning educational facilities; ergonomics in computerized offices; and…

  3. The Evaluation of SISMAKOM (Computerized SDI Project).

    Science.gov (United States)

    University of Science, Penang (Malaysia).

    A survey of 88 users of SISMAKOM, a computerized selective dissemination of information (SDI) and document delivery service provided by the Universiti Sains Malaysia and four other Malaysian universities, was conducted in August 1982 in order to collect data about SISMAKOM and to assess the value of a computerized SDI service in a developing…

  4. Computerized Sociometric Assessment for Preschool Children

    Science.gov (United States)

    Endedijk, Hinke M.; Cillessen, Antonius H. N.

    2015-01-01

    In preschool classes, sociometric peer ratings are used to measure children's peer relationships. The current study examined a computerized version of preschool sociometric ratings. The psychometric properties were compared of computerized sociometric ratings and traditional peer ratings for preschoolers. The distributions, inter-item…

  5. Short-term prognosis of mild coronary stenosis diagnosed by coronary computerized tomography in patients with acute chest pain%冠状动脉轻度狭窄急性胸痛低危患者的短期预后

    Institute of Scientific and Technical Information of China (English)

    田洪森; 要跟东; 赵梦华; 徐宝元; 张凯; 刘津军; 石建平; 沈玉珏; 霍燕飞

    2013-01-01

    目的:探讨冠状动脉CT成像显示为轻度狭窄(狭窄程度25%~50%)的急性胸痛低危患者的短期预后以明确其是否需要进一步行诊断性检查。方法纳入2008年3月~2012年2月邯郸市中心医院心肌梗死溶栓(TIMI)危险评分为低危、冠状动脉CT成像显示为轻度狭窄的急性胸痛患者215例。通过观察患者30天内的主要不良心血管事件(心肌梗死、不稳定心绞痛、冠状动脉血运重建和心血管死亡),以明确行进一步诊断检查的必要性。结果30 d随访期间,仅1例患者(0.5%)发生了主要不良心血管事件(95%CI:0%~2.6%),该患者在住院期间第3次复查肌钙蛋白T时呈阳性结果。无患者发生心血管死亡或需要血运重建。结论冠状动脉CT成像显示为轻度狭窄的急性胸痛患者近期发生主要不良心血管事件的可能性非常低,对此类患者行系列心脏生物学标志物检查有可能获益,但无需行进一步诊断检查。%Objective To investigate the short-term prognosis of mild coronary stenosis (25%-50%) diagnosed by coronary computerized tomography (CT) in the patients with acute chest pain, and determine if they need further diagnostic examinations. Methods The patients (n=215) with lower risk TIMI scores and mild coronary stenosis diagnosed by coronary CT were chosen from Handan Central Hospital from Mar. 2008 to Feb. 2012. The necessity of further diagnostic examinations was determined through observing the incidence of major adverse cardiovascular events (MACE) within 30 days including myocardial infarction, unstable angina, coronary revascularization and cardiovascular death. Results During 30-dya follow-up period, there was only one patients (0.5%) with MACE (95%CI:0%~2.6%), who had positive results of cardiac troponin T reexamined for three times during hospitalization. No patients experienced cardiovascular death or required coronary revascularization. Conclusion The

  6. Evaluación de la disponibilidad, utilización y costos de la tomografía computarizada en el estado de Morelos, México Assessment of the availability, utilization, and costs of computerized tomography in Morelos, Mexico

    Directory of Open Access Journals (Sweden)

    John Pérez-Rodríguez

    2002-09-01

    Full Text Available Objetivo. Evaluar la disponibilidad, utilización y costos económicos de la tomografía computarizada (TC en hospitales públicos y privados en el estado de Morelos, México. Material y métodos. Mediante un estudio transversal efectuado entre enero y abril de 1999, se evaluaron cuatro hospitales en el estado de Morelos, dos públicos y dos privados. Se llevaron a cabo entrevistas individuales con los directores, administradores, médicos radiólogos y jefes de mantenimiento. Se realizó un análisis estadístico descriptivo de las variables, disponibilidad, utilización y costos, así como una evaluación integral de la tomografía, haciendo énfasis en la variabilidad de los patrones observados en los hospitales participantes en el estudio. Resultados. La TC es una tecnología utilizada en los hospitales del estado de Morelos desde hace más de 10 años. Aun cuando existen programas de mantenimiento preventivo y correctivo a los equipos de tomografía, sus costos son muy elevados. Además se carece de estrategias que permitan evaluar la tecnología antes de su adquisición y durante su utilización. El estudio no incluyó aspectos relativos a la correcta indicación clínica de la TC, ni a sus posibles efectos secundarios. Conclusiones. Los hallazgos obtenidos a partir de la presente investigación fueron los siguientes: a existe una carencia de procesos de evaluación y gestión tecnológica, que permita a las unidades hospitalarias un manejo eficiente de la tomografía computarizada, y b también se carece de mecanismos para regular la adquisición, evaluar la tecnología y seleccionar las mejores alternativas en función de su efectividad, eficacia, seguridad y accesibilidad.Objective. To assess the availability, utilization, and costs of computerized tomography (CT scan in private and public hospitals in Morelos State, Mexico. Material and Methods. From January to April 1999, a cross-sectional study was carried out in two private and two

  7. A computerized scheme for localization of vertebral bodies on body CT scans

    Science.gov (United States)

    Hayashi, Tatsuro; Chen, Huayue; Miyamoto, Kei; Zhou, Xiangrong; Hara, Takeshi; Yokoyama, Ryujiro; Kanematsu, Masayuki; Hoshi, Hiroaki; Fujita, Hiroshi

    2011-03-01

    The multidetector row computed tomography (MDCT) method has the potential to be used for quantitative analysis of osteoporosis with higher accuracy and precision than that provided by conventional two-dimensional methods. It is desirable to develop a computer-assisted scheme for analyzing vertebral geometry using body CT images. The aim of this study was to design a computerized scheme for the localization of vertebral bodies on body CT images. Our new scheme involves the following steps: (i) Re-formation of CT images on the basis of the center line of the spinal canal to visually remove the spinal curvature, (ii) use of information on the position of the ribs relative to the vertebral bodies, (iii) the construction of a simple model on the basis of the contour of the vertebral bodies on CT sections, and (iv) the localization of individual vertebral bodies by using a template matching technique. The proposed scheme was applied to 104 CT cases, and its performance was assessed using the Hausdorff distance. The average Hausdorff distance of T2-L5 was 4.3 mm when learning models with 100 samples were used. On the other hand, the average Hausdorff distance with 10 samples was 5.1 mm. The results of our assessments confirmed that the proposed scheme could provide the location of individual vertebral bodies. Therefore, the proposed scheme may be useful in designing a computer-based application that analyzes vertebral geometry on body CT images.

  8. Psychometrics behind Computerized Adaptive Testing.

    Science.gov (United States)

    Chang, Hua-Hua

    2015-03-01

    The paper provides a survey of 18 years' progress that my colleagues, students (both former and current) and I made in a prominent research area in Psychometrics-Computerized Adaptive Testing (CAT). We start with a historical review of the establishment of a large sample foundation for CAT. It is worth noting that the asymptotic results were derived under the framework of Martingale Theory, a very theoretical perspective of Probability Theory, which may seem unrelated to educational and psychological testing. In addition, we address a number of issues that emerged from large scale implementation and show that how theoretical works can be helpful to solve the problems. Finally, we propose that CAT technology can be very useful to support individualized instruction on a mass scale. We show that even paper and pencil based tests can be made adaptive to support classroom teaching.

  9. Pilot project for the establishment of diagnosis reference level in pediatric computerized tomography in Rio de Janeiro city, RJ, Brazil; Projeto piloto para o estabelecimento de niveis de referencia de diagnostico em tomografia computadorizada pediatrica no municipio do Rio de Janeiro, RJ, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Jesus, Fillipe Machado de

    2014-08-01

    Computed tomography (CT) is an important method of diagnostic imaging has been widely used around the world. However, this important diagnostic tool has led to a considerable increase in the frequency of examinations, often without proper clinical justification. Consequently, CT is one of the diagnostic procedures that contributes most to the collective dose. Scientific studies show that the concern in pediatric procedures should be even higher. Despite the fact that these patients have a higher radiosensitivity and a higher life expectancy, the protocols of the examinations are not optimized and adult protocols are applied. Moreover, a recent study performed in the United States showed that one third of the examinations was not justified. The aim of this study was to conduct a pilot study of dose indicators in pediatric CT in four hospitals, in order to verify the feasibility of the diagnostic reference levels establishment for the county of Rio de Janeiro. The dose descriptors were estimated from the beam dosimetry by applying the protocols used in each examination. The total patient sample included 358 children of different age groups. The results observed in examinations of whole trunk (routine chest, upper abdomen and pelvis) and upper abdomen in Institution A, for patients aged 5-10 years, indicated that the mAs values used were not properly selected for patients' body mass index, presenting however, conformity with UK reference levels. In the case of head CT scans and routine chest CT scans in Institution B, although patients aged 5-10 years have shown conformity with UK reference levels, the kV and mAs values used, in some examinations, were also inappropriate for the patient characteristics. Similar result was observed in examinations of head and high resolution chest for patients neonates, in Institution D. For head and routine chest examinations of 1-5 years' age group, was Institution B that showed the lowest DLP values. This result was due to

  10. Predictive value of early F-18-fluoro-deoxyglucose positron emission tomography in chemosensitive relapsed lymphoma

    NARCIS (Netherlands)

    Schot, B; van Imhoff, G; Pruim, J; Sluiter, W; Vaalburg, W; Vellenga, E

    2003-01-01

    F-18-fluoro-deoxyglucose (FDG) positron emission tomography (PET) might be a better tool than computerized tomography (CT) in predicting long-term treatment outcome in patients with relapsed chemosensitive lymphoma who are candidates for autologous stem cell transplantation (ASCT). We studied patien

  11. On the Pitfalls and Limitations of Applying Petrophysical Models to Geophysical Tomograms: Examples in Cross-Borehole Radar and Electrical-Resistivity Tomography

    Science.gov (United States)

    Day-Lewis, F. D.; Singha, K.; Binley, A. M.

    2004-05-01

    Geophysical field data have traditionally provided qualitative information on aquifer structure for hydrogeologic characterization; however, there is increasing interest in the application of petrophysical models to convert geophysical tomograms of electrical resistivity or radar velocity, for example, to hydrologic parameters, such as permeability, porosity, water content, and (or) salinity. Unfortunately, application of theoretical or empirical petrophysical models may be inappropriate in many situations, given the limited and variable resolution of tomographic estimates. The resolution of tomograms is a function of (1) the measurement physics, for example, electrical conduction or electromagnetic wave propagation; (2) the parameterization and regularization used for inversion; (3) measurement error; and (4) the length scale of heterogeneity. We present a framework to predict how core-scale relations between geophysical properties and hydrologic parameters break down in the inversion, which produces smoothly-varying pixel-scale estimates. Our approach upscales the core-scale relationship to the pixel-scale based on the model resolution matrix from the inversion, random field averaging, and spatial statistics of the geophysical property. In synthetic examples, we use the approach to evaluate the utility of tomograms for quantitative hydrologic estimation, in light of their resolution-dependent limitations. Comparison of examples for cross-borehole electrical resistivity tomography and radar tomography demonstrates the role of the measurement physics on the spatially-variable pixel-scale relationships between geophysical estimates and hydrologic parameters of interest. The goals of this work are to (1) raise awareness of the limitations of geophysical data, (2) provide a framework to improve survey design and assess tomograms for hydrologic estimation, and (3) promote additional research to improve the links between geophysical and hydrogeologic characterization.

  12. Computerizing marine biota: a rational approach

    Digital Repository Service at National Institute of Oceanography (India)

    Chavan, V.S.; Chandramohan, D.; Parulekar, A.H.

    Data on marine biota while being extensive are also patchy and scattered; thus making retrieval and dissemination of information time consuming. This emphasise the need for computerizing information on marine biota with the objective to collate...

  13. Modified Head Shake Computerized Dynamic Posturography

    Science.gov (United States)

    2009-12-01

    form of dizziness (in- cluding complaints of lightheadedness, vertigo , or un- steadiness) lasting longer than 1 hr or recurring for greater than 1...noted limitations. Method: Forty participants ranging in age from 20 to 79 years with no history of dizziness completed Conditions 2 and 5 of the SOT...shake, Sensory Organization Test, computerized dynamic posturography, dizziness Computerized dynamic posturography (CDP) is anassessment of an

  14. Computerized tomographic evaluation of intracranial metastases

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bo Yong; Lee, Mi Sook; Choi, Jin Ok; Jeon, Doo Sung; Kim, Hong Soo; Rhee, Hak Song [Presbyterian Medical Center, Chonju (Korea, Republic of)

    1986-12-15

    In a study of intracranial metastases, 46 cases having satisfactory clinical, operative and histological proofs were analyzed by computerized tomography at Presbyterian Medical Center from May, 1982 to February, 1986. The results were as follows: 1. The male to female ratio of intracranial metastases were 67:33. The 5th decade group (34.8%) was the most prevalent age group, followed by the 6th decade (21.7%) and 7th decade (21.7%). 2. The number of lesions was found be: single -25 cases (54.3%); multiple -21 cases (45.7%). 3. The source of intracranial metastases found to be: lung 15 cases (32.6%); unknown 12 cases (26.0%); chorioca 3 cases (6.5%); liver 3 cases (6.5%); stomach 2 cases (4.3%); parotid, breast, kidney, prostate, melanoma, rectal ca, rhabdomyosarcoma, nasal ca, lymphoma, testicular ca, cervix, each 1 case (2.2%). 4. The locations of the intracranial metastases were as follows: Cerebral hemisphere 37.7% in parietal region Cerebral hemisphere 15.9% in in frontal region Cerebral hemisphere 13.4% in occipital region Cerebral hemisphere 10.5% in temporal region Cerebellar hemisphere 3.2% Cerebellopontine angle 3.2% Intraventricular 4.8% Meninges 4.8% Skull vault 6.5% 5. Peritumor edema was found to be: Grade II-17 cases (37.0%): Grade III-14 cases (30.4%); Grade I-8 cases (17.4%); Grade 0-7 cases (15.2%) in that order. 6. The chief complaints of intracranial metastases on admission, were as follows: Headache 30 cases (65.2%); Vomiting 11 cases (23.9%); deteriorated mental state 10 cases (21.7%); Hemiplegia 7 cases (15.2%); visual disturbance 6 cases (13.0%); hemiparesis 4 cases (8.7%); seizure 4 cases (8.7%); other symptoms were less frequent. 7. On pre-contrast scan, hyperdense lesions were present in 18 cases (39.1%); hypodense lesions in 15 cases (32.6%); mixed density in 8 cases (17.4%); isodensity was present in 5 cases (10.9%). On post-contrast scan, ring enhancement was seen in 19 cases (41.3%); nodular enhancement in 17 cases (37%), mixed ring

  15. 螺旋 CT多期扫描在慢性上尿路梗阻患者分肾功能评估中的价值%Value of contrast enhanced spiral computerized tomography for differential renal functional assessment in patients with chronic obstructive uropathy

    Institute of Scientific and Technical Information of China (English)

    刘豪; 鞠文彬; 王晓梅; 田爱娟; 孙卫兵

    2014-01-01

    目的:通过螺旋CT多期扫描对慢性尿路梗阻且血肌酐正常患者的分肾功能进行评估。方法前瞻性研究65例单侧或双侧慢性上尿路梗阻并且血肌酐正常的成年患者,60例为单侧梗阻,对侧肾正常,其余5例为双侧梗阻。所有患者均行螺旋CT多期扫描及99mTc-DTPA核素肾动态显像检查。 CT用来明确梗阻的原因,间接测定双肾的肾小球滤过率( GFR),分析梗阻肾脏CT GFR和同位素GFR 之间的相关性。结果梗阻肾脏同位素GFR为(36.9±9.79)mL/min,CT GFR为(37.8±10.53)mL/min,梗阻肾脏同位素GFR与相应的CT GFR之间呈显著正相关(r=0.74,P<0.001),其同位素GFR与CT GFR差异没有显著性意义(P=0.28);正常肾脏的同位素GFR为(62.3±13.07)mL/min,CT GFR为(62.1±10.11)mL/min,正常肾脏的同位素GFR和CT GFR比较,同样呈显著正相关(r=0.78,P<0.001),其同位素GFR与CT GFR差异没有显著性意义(P=0.75)。结论在梗阻肾脏及正常肾脏的功能评估中,螺旋CT多期扫描对于总肾功能和分肾功能的计算与核素肾动态显像一样准确。%Objective To evaluate contrast enhanced spiral computerized tomography ( CT) for differential renal functional assessment in the patients with chronic obstructive uropathy and normal serum creatinine .Methods We chose 65 patients with unilateral or bilateral chronic renal obstruction and normal serum creatinine in the prospective study .Sixty patients had unilateral obstruction and a normal contralateral kidney and the remaining five had bilateral obstruction .All patients under-went contrast enhanced spiral CT together with 99 Tcmercaptoacetyltriglycine renal scan .CT was used to identify the cause of obstruction and selectively determine the glomerular filtration rate ( GFR) of the differential kidneys .We analyzed the rela-tionship between isotope GFR and CT GFR in the

  16. 基于CT血管造影三维重建的Corona Mortis动脉解剖学研究及其临床意义%The anatomical study of the corona mortis artery on three-dimensional computerized tomography angiography and its clinical significance

    Institute of Scientific and Technical Information of China (English)

    赵辉; 张轩轩; 张丕军; 隆腾飞; 王钢

    2013-01-01

    Objective To investigate the incidence and location of the corona mortis artery by means of three dimensional (3D) reconstruction of computerized tomography angiography (CTA) as well as the clinical significance of the knowledge in the treatment of pelvic and acetabular fractures via ilioinguinal and Stoppa approaches.Methods Radiological and clinical data from 80 patients (160 hemi-pelvises) undergoing aorta abdominalis CTA between Deeember 2010 and May 2012 were collected.This study involved 34 males and 46 females,aged from 19 to 84 years (average,47.2 years).The.dicom format CTA data were used for 3D reconstruction using the Mimics software.The incidence and origin of the corona mortis artery crossing the superior pubic ramus into the obturator foramen were observed and the distances between the corona mortis artery and the pubic symphysis were measured on the 3D reconstruction images.The incidences were compared between hemi-pelvises,genders and age groups of ≤50 and > 50 years.Results In the 160 hemi-pelvises,altogether 29 corona mortis arteries were detected,giving a total incidence of 18.1% (29/160).Of them,14(14/80,17.5%) were found on the left side and 15 (15/80,18.8%) on the right; 16(16/92,17.4%) in the female patients and 13 (13/68,19.1%) in the male patients; 14 (14/98,14.3%) in the ≤50 age group and 15(15/62,24.2%) in the > 50 age group.There were no significant differences regarding the incidence between hemi-pelvises,genders or age groups (P > 0.05).The distances between the corona mortis artery and the pubic symphysis averaged 53.70 ±4.00 mm.Conclusions Since CTA 3D reconstruction images can clearly demonstrate the corona mortis artery,abdominal aorta CTA should be recommended before operative treatment of pelvic and acetabular fractures via the ilioinguinal and Stoppa approaches to make sure that no operative accident will occur due to presence of the corona mortis artery.We should be alert to this artery variation when

  17. Unexplained heterochromia. Intraocular foreign body demonstrated by computed tomography.

    Science.gov (United States)

    Barr, C C; Vine, A K; Martonyi, C L

    1984-01-01

    Standard radiographic techniques are often inadequate in demonstrating the presence and location of intraocular foreign bodies. Computerized axial tomography was used to confirm the presence of a metallic foreign body in a patient with heterochromia iridis and suspected ocular siderosis in whom no foreign material was found by conventional examination methods.

  18. Applying x-ray tomography in the field of vertebrate biology: form, function, and evolution of the skull of caecilians (Lissamphibia: Gymnophiona)

    Science.gov (United States)

    Kleinteich, Thomas; Beckmann, Felix; Herzen, Julia; Summers, Adam P.; Haas, Alexander

    2008-08-01

    Evolutionary research in biology relies on the comparison of different individuals of different species in order to explore the history of today's biodiversity. Synchrotron radiation based high resolution X-ray tomography (SRμCT) rapidly generates detailed three dimensional datasets. At the beamlines W2 and BW2 of the storage ring DORIS at DESY, Hamburg, Germany, we used SRμCT to study the cranial anatomy of different species and different developmental stages of caecilians (Lissamphibia: Gymnophiona). Here we describe a work-flow for analysis of the SRμCT data that covers segmentation of tissues in Amira® (Mercury Computer Systems), photorealistic rendering and animation in MayaTM, rapid prototyping, and morphometrics. The integration of different analyses of SRμCT data in our study resulted in a comprehensive understanding of form, function, and evolution of caecilian skulls. SRμCT imaging has the potential to become a standard technique for life sciences applications in the near future.

  19. A 45° saw-dicing process applied to a glass substrate for wafer-level optical splitter fabrication for optical coherence tomography

    Science.gov (United States)

    Maciel, M. J.; Costa, C. G.; Silva, M. F.; Gonçalves, S. B.; Peixoto, A. C.; Ribeiro, A. Fernando; Wolffenbuttel, R. F.; Correia, J. H.

    2016-08-01

    This paper reports on the development of a technology for the wafer-level fabrication of an optical Michelson interferometer, which is an essential component in a micro opto-electromechanical system (MOEMS) for a miniaturized optical coherence tomography (OCT) system. The MOEMS consists on a titanium dioxide/silicon dioxide dielectric beam splitter and chromium/gold micro-mirrors. These optical components are deposited on 45° tilted surfaces to allow the horizontal/vertical separation of the incident beam in the final micro-integrated system. The fabrication process consists of 45° saw dicing of a glass substrate and the subsequent deposition of dielectric multilayers and metal layers. The 45° saw dicing is fully characterized in this paper, which also includes an analysis of the roughness. The optimum process results in surfaces with a roughness of 19.76 nm (rms). The actual saw dicing process for a high-quality final surface results as a compromise between the dicing blade’s grit size (#1200) and the cutting speed (0.3 mm s-1). The proposed wafer-level fabrication allows rapid and low-cost processing, high compactness and the possibility of wafer-level alignment/assembly with other optical micro components for OCT integrated imaging.

  20. Computerized Adaptive Personality Testing: A Review and Illustration With the MMPI-2 Computerized Adaptive Version.

    Science.gov (United States)

    Forbey, Johnathan D.; Ben-Porath, Yossef S.

    2007-01-01

    Computerized adaptive testing in personality assessment can improve efficiency by significantly reducing the number of items administered to answer an assessment question. Two approaches have been explored for adaptive testing in computerized personality assessment: item response theory and the countdown method. In this article, the authors…

  1. 3D electric resistivity tomography (ERT) methodologies applied on selected heavily urbanized areas of the basin of Mexico to detect buried fractures and subsidence problems

    Science.gov (United States)

    Chavez Segura, R. E.; Cifuentes-Nava, G.; Tejero, A.; Hernandez, E.

    2012-12-01

    Urban development in modern cities require of a more integral knowledge of the subsurface, mainly on those areas, where human concentrations increase. Mexico City is one of such an example, where it constitutes one of the largest concentrations of human activities in the world. Most of the urban area is underlain by lacustrine sediments of the former lakes, and confined by important volcanic ranges. Such sediments offer poor foundation conditions for constructive purposes. Therefore, high risk areas have to be identified to prevent accidents and disastrous events. Geophysical techniques can be employed to understand the physical characteristics of the subsurface. Two examples are presented in this investigation. A residential complex named La Concordia is located towards the central portion of the basin that consists of six four storey buildings in an area of 33x80 m2. Finally, a block of small houses (50x50 m2) is found to the southern limit of the basin; close to the Chichinautzin range within the town of Tecomitl. Both zones suffer of strong damage in their structures due to fractures and subsidence within the subsoil. Therefore, Electric Resistivity Tomography (ERT) was carried out to characterize the subsoil beneath these urban complexes. A special array ('horse-shoe' geometry) 'L' employing Wenner-Schlumberger techniques, in addition to equatorial-dipole and minimum-coupling arrays were carried out to fully 'illuminate' beneath the constructions. Computed resistivity models for both examples depicted the buried fracture pattern affecting the urban complexes. Such patterns seem to extend beyond the limits of the surveyed areas, and are probably part of a more complex fracture system. It is very likely that fractures have been produced due to the poorly consolidated clays that cover most of the central part of the Valley of Mexico; the intense water extraction, that form 'voids' in the subsoil causing subsidence effects and finally the existence of regional

  2. Centre of Rotation Determination Using Projection Data in X-ray Micro Computed Tomography

    OpenAIRE

    Olander, Birger

    1994-01-01

    There are several methods available to determine the Centre Of Rotation, COR, and align detectors and X-ray focus to COR in X-ray computed tomography. Some methods use narrow rods/needles or specially made alignment objects or phantoms. In X-ray Micro Computed Tomography (or Computerized Micro Tomography), μCT (CMT), methods using sample projection data for COR measurements are preferred since the replacement of alignment objects with samples often displace translation stages and make the ali...

  3. Human-eye versus computerized color matching.

    Science.gov (United States)

    Yap, A U; Sim, C P; Loh, W L; Teo, J H

    1999-01-01

    This project compared the difference in color matching between human-eye assessment and computerized colorimetry. Fifty dental personnel were asked to color match Vita Lumin shade tabs to seven different randomly arranged test tabs from the Z100 shade guide. All evaluators were blinded to the shades of the test tabs and were asked to match only body shade of the Vita Lumin tab to the middle third or body of each test tab. The results obtained were subsequently computed into L*a*b* values and compared with results obtained by computerized colorimetry. Results indicate that the difference in color matching between human-eye assessment and computerized colorimetry is shade dependent. Discrepancy was significant for b* coordinates for shades A1 and B2 and L* and b* coordinates for shade C4. For all shades evaluated, color difference between human-eye and computerized color matching is perceivable under clinical settings, as delta E values are greater than 3. There is a need for correction factors in the formal specification of the color-matching software due to the discrepancy between human-eye and computerized colorimetric color matching.

  4. Computerized occlusal analysis in bruxism

    Directory of Open Access Journals (Sweden)

    Lazić Vojkan

    2006-01-01

    Full Text Available Introduction. Sleep bruxism as nocturnal parafunction, also known as tooth grinding, is the most common parasomnia (sleep disorder. Most tooth grinding occurs during rapid eye movement - REM sleep. Sleep bruxism is an oral habit characterized by rhythmic activity of the masticatory muscles (m. masseter that causes forced contact between dental surfaces during sleep. Sleep bruxism has been associated with craniomandibular disorders including temporomandibular joint discomfort, pulpalgia, premature loss of teeth due to excessive attrition and mobility, headache, muscle ache, sleep interruption of an individual and problems with removable and fixed denture. Basically, two groups of etiological factors can be distinguished, viz., peripheral (occlusal factors and central (pathophysiological and psychological factors. The role of occlusion (occlusal discrepancies as the causative factor is not enough mentioned in relation to bruxism. Objective. The main objective of this paper was to evaluate the connection between occlusal factors and nocturnal parafunctional activities (occlusal disharmonies and bruxism. Method. Two groups were formed- experimental of 15 persons with signs and symptoms of nocturnal parafunctional activity of mandible (mean age 26.6 years and control of 42 persons with no signs and symptoms of bruxism (mean age 26.3 yrs.. The computerized occlusal analyses were performed using the T-Scan II system (Tekscan, Boston, USA. 2D occlusograms were analyzed showing the occlusal force, the center of the occlusal force with the trajectory and the number of antagonistic tooth contacts. Results. Statistically significant difference of force distribution was found between the left and the right side of the arch (L%-R% (t=2.773; p<0.02 in the group with bruxism. The difference of the centre of occlusal force - COF trajectory between the experimental and control group was not significant, but the trajectory of COF was longer in the group of

  5. Dynamic Assessment of EFL Learners' Listening Comprehension via Computerized Concept Mapping

    Science.gov (United States)

    Ebadi, Saman; Latif, Shokoufeh Vakili

    2015-01-01

    In Vygotsky's theory, learner's Zone of Proximal Development (ZPD) and autonomous performance could be further developed through social interaction with an expert. Computerized concept mapping enjoys the advantage of meeting learners' differences and therefore can be applied as a scaffold to support learning process.Taking a dynamic assessment…

  6. The Construction and Uses of CATIA, a Computerized Mathematics Testbank

    Science.gov (United States)

    Burton, Charles R.; Marosz, Wanda A.

    1977-01-01

    Described is the construction of a computerized test bank to generate and score tests in college algebra, trigonometry, and intermediate algebra; including a discussion of uses, advantages and disadvantages of computerized testing. (JLH)

  7. The Construction and Uses of CATIA, a Computerized Mathematics Testbank

    Science.gov (United States)

    Burton, Charles R.; Marosz, Wanda A.

    1977-01-01

    Described is the construction of a computerized test bank to generate and score tests in college algebra, trigonometry, and intermediate algebra; including a discussion of uses, advantages and disadvantages of computerized testing. (JLH)

  8. Improved Design of Crew Operation in Computerized Procedure System of APR1400

    Energy Technology Data Exchange (ETDEWEB)

    Seong, No Kyu; Jung, Yeon Sub; Sung, Chan Ho [KHNP, Daejeon (Korea, Republic of)

    2016-05-15

    The operators perform the paper-based procedures in analog-based conventional main control room (MCR) depending on only communications between operators except a procedure controller such as a Shift Supervisor (SS), however in digital-based MCR the operators can confirm the procedures simultaneously in own console when the procedure controller of computerized procedure (CP) opens the CP. The synchronization and a synchronization function between procedure controller and other operators has to be considered to support the function of crew operation. This paper suggests the improved design of crew operation in computerized procedure system of APR1400. This paper suggests the improved design of APR1400 CPS. These improvements can help operators perform the crew procedures more efficiently. And they reduce a burden of communication and misunderstanding of computerized procedures. These improvements can be applied to CPS after human factors engineering verification and validation.

  9. Atom Probe Tomography 2012

    Science.gov (United States)

    Kelly, Thomas F.; Larson, David J.

    2012-08-01

    In the world of tomographic imaging, atom probe tomography (APT) occupies the high-spatial-resolution end of the spectrum. It is highly complementary to electron tomography and is applicable to a wide range of materials. The current state of APT is reviewed. Emphasis is placed on applications and data analysis as they apply to many fields of research and development including metals, semiconductors, ceramics, and organic materials. We also provide a brief review of the history and the instrumentation associated with APT and an assessment of the existing challenges in the field.

  10. Characterization of transfer function, resolution and depth of field of a soft X-ray microscope applied to tomography enhancement by Wiener deconvolution.

    Science.gov (United States)

    Otón, Joaquín; Pereiro, Eva; Pérez-Berná, Ana J; Millach, Laia; Sorzano, Carlos Oscar S; Marabini, Roberto; Carazo, José M

    2016-12-01

    Full field soft X-ray microscopy is becoming a powerful imaging technique to analyze whole cells preserved under cryo conditions. Images obtained in these X-ray microscopes can be combined by tomographic reconstruction to quantitatively estimate the three-dimensional (3D) distribution of absorption coefficients inside the cell. The impulse response of an imaging system is one of the factors that limits the quality of the X-ray microscope reconstructions. The main goal of this work is to experimentally measure the 3D impulse response and to assess the optical resolution and depth of field of the Mistral microscope at ALBA synchrotron (Barcelona, Spain). To this end we measure the microscope apparent transfer function (ATF) and we use it to design a deblurring Wiener filter, obtaining an increase in the image quality when applied to experimental datasets collected at ALBA.

  11. Study of the positivity of spontaneous and directed diagnosis of leukoaraiosis in the elderly by cranial computerized tomography, and its correlation with cognitive defi cit and cardiovascular risk factors Estudo da positividade do diagnóstico espontâneo e dirigido da leucoaraiose em idosos pela tomografia computadorizada de crânio e sua correlação com déficits cognitivos e fatores de risco cardiovascular

    Directory of Open Access Journals (Sweden)

    Mauricio de Miranda Ventura

    2007-12-01

    Full Text Available OBJECTIVE: To evaluate the prevalence of leukoaraiosis (LA and its correlation with vascular risk factors and the cognitive performance of elderly patients. METHOD: 78 patients were randomly selected and submitted to clinic-laboratorial evaluation for vascular risk factors. Two cognitive tests were performed. All patients were submitted to cranial computerized tomography (CT, which was analyzed in two situations: the spontaneous and the directed way. RESULTS: There was no statistically significant difference between the prevalence of spontaneous and the directed diagnoses of LA (20.5 and 18%, respectively. The presence of LA was not significantly correlated with cognitive impairment. Only age was positively associated with LA. CONCLUSION: Cranial CT is a trustworthy method for the diagnosis of LA. Only age showed a positive association. No clinical implications were found, concerning the cognitive performance of the patients.OBJETIVO: Avaliar a prevalência da leucoaraiose (LA em idosos e correlacioná-los com fatores de risco vasculares e seu desempenho cognitivo. MÉTODO: 78 pacientes foram selecionados aleatoriamente e submetidos a avaliação clinico-laboratorial para fatores de risco vascular. Dois testes cognitivos foram realizados. Todos os pacientes foram submetidos a tomografia computadorizada (TC de crânio, que foi analisada em duas situações: de forma espontânea e dirigida. RESULTADOS: Não houve diferença estatisticamente significativa entre as formas de diagnóstico espontâneo e dirigido da LA (20,5 and 18%, respectivamente. Com relação ao desempenho cognitivo, a presença da LA não determinou prejuízo significativo. Somente a idade mostrou associação positiva com a LA. CONCLUSÃO: A TC de crânio é um método confiável para o diagnóstico de LA. A idade foi o único fator de risco que mostrou associação positiva. Não houve prejuízo quanto ao desempenho cognitivo.

  12. Computerized management information systems and organizational structures

    Science.gov (United States)

    Zannetos, Z. S.; Sertel, M. R.

    1970-01-01

    The computerized management of information systems and organizational structures is discussed. The subjects presented are: (1) critical factors favoring centralization and decentralization of organizations, (2) classification of organizations by relative structure, (3) attempts to measure change in organization structure, and (4) impact of information technology developments on organizational structure changes.

  13. Computerized management support for swine breeding farms.

    NARCIS (Netherlands)

    Huirne, R.B.M.

    1990-01-01

    1. INTRODUCTIONThe investigations described in this thesis have been directed towards computerized management support for swine breeding farms, focused on sow productivity and profitability. The study is composed of three basic parts: (1) basic description and definition of farm man

  14. The EORTC emotional functioning computerized adaptive test

    DEFF Research Database (Denmark)

    Gamper, Eva-Maria; Grønvold, Mogens; Petersen, Morten Aa

    2014-01-01

    The European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Group is currently developing computerized adaptive testing measures for the Quality of Life Questionnaire Core-30 (QLQ-C30) scales. The work presented here describes the development of an EORTC item bank...

  15. An Introduction to the Computerized Adaptive Testing

    Science.gov (United States)

    Tian, Jian-quan; Miao, Dan-min; Zhu, Xia; Gong, Jing-jing

    2007-01-01

    Computerized adaptive testing (CAT) has unsurpassable advantages over traditional testing. It has become the mainstream in large scale examinations in modern society. This paper gives a brief introduction to CAT including differences between traditional testing and CAT, the principles of CAT, psychometric theory and computer algorithms of CAT, the…

  16. The EORTC emotional functioning computerized adaptive test

    DEFF Research Database (Denmark)

    Gamper, Eva-Maria; Grønvold, Mogens; Petersen, Morten Aa;

    2014-01-01

    The European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Group is currently developing computerized adaptive testing measures for the Quality of Life Questionnaire Core-30 (QLQ-C30) scales. The work presented here describes the development of an EORTC item bank...

  17. [Computerization of hospital blood banks in France].

    Science.gov (United States)

    Daurat, G; Py, J-Y

    2012-11-01

    In France, most blood products are delivered by the établissement francais du sang, directly to the recipients, and hospital blood banks deliver a minor part, but are independent from it. However that may be, hospital blood banks are hazardous activities regarding to recipients, blood products, blood supply of the hospital and regional blood supply. Because of the high risk level, a computerized information system is compulsory for all hospital blood banks, except for those only devoted to vital emergency transfusion. On the field, the integration of computerization in the different processes is very heterogeneous. So, it has been decided to publish guidelines for computerizing hospital blood banks information systems and production management. They have been built according to risk assessment and are intended to minimize those risks. The principle is that all acquisition and processing of data about recipients or blood products and tracking, must be fully computerized and that the result of all manual processes must be checked by computer before proceeding to the next step. The guidelines list the different processes and, for each of them, the functions the software must play. All together, they form the basic level all hospital blood banks should reach. Optional functions are listed. Moreover, the guidelines are also aimed to be a common tool for regional health authorities who supervise hospital blood banks.

  18. Computerized adaptive testing: overview and introduction

    NARCIS (Netherlands)

    Meijer, Rob R.; Nering, Michael L.

    1999-01-01

    Use of computerized adaptive testing (CAT) has increased substantially since it was first formulated in the 1970s. This paper provides an overview of CAT and introduces the contributions to this Special Issue. The elements of CAT discussed here include item selection procedures, estimation of the la

  19. Computerized Testing: The Hidden Figures Test.

    Science.gov (United States)

    Jacobs, Ronald L.; And Others

    1985-01-01

    This study adapted the Hidden Figures Test for use on PLATO and determined the reliability of the computerized version compared to the paper and pencil version. Results indicate the test was successfully adapted with some modifications, and it was judged reliable although it may be measuring additional constructs. (MBR)

  20. Computerized management support for swine breeding farms

    NARCIS (Netherlands)

    Huirne, R.B.M.

    1990-01-01

    1. INTRODUCTION

    The investigations described in this thesis have been directed towards computerized management support for swine breeding farms, focused on sow productivity and profitability. The study is composed of three basic parts: (1) basic description and

  1. Computerized Financial Reporting Based on GAAP.

    Science.gov (United States)

    Tikkanen, Stan; Liljeberg, Burt

    1983-01-01

    Describes the statewide computerized system developed in Minnesota following the 1976 enactment of the Uniform Financial Accounting and Reporting Standards (UFARS) law. UFARS includes provisions for an advisory council responsible for recommending accounting and reporting procedures, and seven data processing centers to serve all 560 Minnesota…

  2. Computerized triaxial test control methods

    DEFF Research Database (Denmark)

    Sabaliauskas, Tomas; Ibsen, Lars Bo

    2016-01-01

    capabilities of the setup are extended by using a programmable hydraulic piston with real time feedback loops. The control methods provided by the controller mimic those applied in computer simulations. Force control, displacement control or a combination of both can be used. Single diameter height sample...... control methods provide access to testing both direct and inverse stiffness matrix response as well as to observe strain creep and stress relaxation directly....

  3. Assessment of cardiac stroke volume in patients with implanted cardiac pacemaker using parametric electrical impedance tomography: a theoretical 2D study.

    Science.gov (United States)

    Mhajna, Muhammad; Abboud, Shimon

    2013-05-01

    The present theoretical study examines the ability to estimate cardiac stroke volume (CSV) in patients with implanted cardiac pacemaker using parametric electrical impedance tomography (pEIT) in a 2D computerized model of the thorax. CSV is a direct indicator of the cardiac pumping efficiency. The commonly used methods for measuring CSV require the invasive procedure of right heart catheterization or use expensive imaging techniques (i.e., MRI). Hence, experience with these techniques for diagnosis and monitoring has been limited to hospitalized patients. In the present study, pEIT scheme was applied in a computerized 2D model of the human thorax with implanted cardiac device to determine the left ventricular (LV) volume at different cardiac cycle phases. The LV was simulated as a prolate ellipse with its axes' lengths as the reconstruction parameters while all other geometries and conductivity values remained constant. An optimization was carried out in order to ensure that the ellipse is the appropriate model for the LV at each cardiac cycle phase. LV volumes calculated by both the pEIT algorithm and the ellipsoid model are consistent. A high correlation (ρ = 0.99) between the true and reconstructed volumes was found. The SV calculation error was ∼1%. The results suggest that the LV volume can be estimated using the pEIT method in a 2D computerized model, and that the method has the potential to be used for monitoring patients with implanted cardiac pacemaker.

  4. The importance of investigation of anatomic variations in the ethmoid cells by computerized tomography in the planning of endoscopic nasal surgery; A importancia da investigacao de variacoes anatomicas das celulas etmoidais atraves da tomografia computadorizada no planejamento da cirurgia endoscopica nasal

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, Cristiane Regina; Wafae, Nader; Nascimento, Sergio Ricardo Rios; Camelo, Julio Cesar; Maciel, Luana Teixeira; Consolari, Mario Agostinho Severo [Centro Universitario Sao Camilo, Sao Paulo, SP (Brazil)], e-mail: crisruiz@saocamilo-sp.br, e-mail: riosnascimento@uol.com.br

    2009-01-15

    The ethmoidal cells comprise many cavities that show many anatomical variations. Some of these variations deserve special attention when associated with sinusitis and the need of surgery. Computed tomography, considered a gold standard on the pathological investigation of the nasal cavity and the anatomic description of paranasal sinus, offers information about these cells, essential to minimize the surgical risks. The authors present a bibliographic revision of the importance of computed tomography on the investigation of anatomic variations of ethmoid cells. Not recurrent cells in all individuals, like Haller's cells, Onodi's cells and pneumatization of agger nasi, will do the endoscopic approach with precaution. The ethmoidal roof evaluation will result in more safety on the upper limits of the nasal cavity. The size and pneumatization level of ethmoidal bulla, ethmoidal crest, and middle nasal concha are important on the evaluation of the endoscopic accesses and the gravity of the stroked pathology and even diagnose your origin. (author)

  5. CT based computerized identification and analysis of human airways: a review.

    Science.gov (United States)

    Pu, Jiantao; Gu, Suicheng; Liu, Shusen; Zhu, Shaocheng; Wilson, David; Siegfried, Jill M; Gur, David

    2012-05-01

    As one of the most prevalent chronic disorders, airway disease is a major cause of morbidity and mortality worldwide. In order to understand its underlying mechanisms and to enable assessment of therapeutic efficacy of a variety of possible interventions, noninvasive investigation of the airways in a large number of subjects is of great research interest. Due to its high resolution in temporal and spatial domains, computed tomography (CT) has been widely used in clinical practices for studying the normal and abnormal manifestations of lung diseases, albeit there is a need to clearly demonstrate the benefits in light of the cost and radiation dose associated with CT examinations performed for the purpose of airway analysis. Whereas a single CT examination consists of a large number of images, manually identifying airway morphological characteristics and computing features to enable thorough investigations of airway and other lung diseases is very time-consuming and susceptible to errors. Hence, automated and semiautomated computerized analysis of human airways is becoming an important research area in medical imaging. A number of computerized techniques have been developed to date for the analysis of lung airways. In this review, we present a summary of the primary methods developed for computerized analysis of human airways, including airway segmentation, airway labeling, and airway morphometry, as well as a number of computer-aided clinical applications, such as virtual bronchoscopy. Both successes and underlying limitations of these approaches are discussed, while highlighting areas that may require additional work.

  6. CT based computerized identification and analysis of human airways: A review

    Energy Technology Data Exchange (ETDEWEB)

    Pu Jiantao; Gu Suicheng; Liu Shusen; Zhu Shaocheng; Wilson, David; Siegfried, Jill M.; Gur, David [Imaging Research Center, Department of Radiology, University of Pittsburgh, 3362 Fifth Avenue, Pittsburgh, Pennsylvania 15213 (United States); School of Computing, University of Utah, Salt Lake City, Utah 84112 (United States); Department of Radiology, Henan Provincial People' s Hospital, Zhengzhou 450003 (China); Department of Medicine, University of Pittsburgh, 580 S. Aiken Avenue, Suite 400, Pittsburgh, Pennsylvania 15232 (United States); Department of Pharmacology and Chemical Biology, Hillman Cancer Center, Pittsburgh, Pennsylvania 15213 (United States); Imaging Research Center, Department of Radiology, University of Pittsburgh, 3362 Fifth Avenue, Pittsburgh, PA 15213 (United States)

    2012-05-15

    As one of the most prevalent chronic disorders, airway disease is a major cause of morbidity and mortality worldwide. In order to understand its underlying mechanisms and to enable assessment of therapeutic efficacy of a variety of possible interventions, noninvasive investigation of the airways in a large number of subjects is of great research interest. Due to its high resolution in temporal and spatial domains, computed tomography (CT) has been widely used in clinical practices for studying the normal and abnormal manifestations of lung diseases, albeit there is a need to clearly demonstrate the benefits in light of the cost and radiation dose associated with CT examinations performed for the purpose of airway analysis. Whereas a single CT examination consists of a large number of images, manually identifying airway morphological characteristics and computing features to enable thorough investigations of airway and other lung diseases is very time-consuming and susceptible to errors. Hence, automated and semiautomated computerized analysis of human airways is becoming an important research area in medical imaging. A number of computerized techniques have been developed to date for the analysis of lung airways. In this review, we present a summary of the primary methods developed for computerized analysis of human airways, including airway segmentation, airway labeling, and airway morphometry, as well as a number of computer-aided clinical applications, such as virtual bronchoscopy. Both successes and underlying limitations of these approaches are discussed, while highlighting areas that may require additional work.

  7. Computerized tomographic analysis of fluid flow in fractured tuff

    Energy Technology Data Exchange (ETDEWEB)

    Felice, C.W.; Sharer, J.C. (Terra Tek, Inc., Salt Lake City, UT (United States)); Springer, E.P. (Los Alamos National Lab., NM (United States))

    1992-01-01

    The purpose of this summary is to demonstrate the usefulness of X-ray computerized tomography to observe fluid flow down a fracture and rock matrix imbibition in a sample of Bandelier tuff. This was accomplished by using a tuff sample 152.4 mm long and 50.8 mm in diameter. A longitudinal fracture was created by cutting the core with a wire saw. The fractured piece was then coupled to its adjacent section to that the fracture was not expected. Water was injected into a dry sample at five flow rates and CT scanning performed at set intervals during the flow. Cross sectional images and longitudinal reconstructions were built and saturation profiles calculated for the sample at each time interval at each flow rate. The results showed that for the test conditions, the fracture was not a primary pathway of fluid flow down the sample. At a slow fluid injection rate into the dry sample, the fluid was imbibed into the rock uniformly down the length of the core. With increasing injection rates, the flow remained uniform over the core cross section through complete saturation.

  8. In Vitro Assessment of Optical Properties of Blood by Applying the Extended Huygens-Fresnel Principle to Time-Domain Optical Coherence Tomography Signal at 1300 nm

    Directory of Open Access Journals (Sweden)

    Dan P. Popescu

    2008-01-01

    Full Text Available A direct method for the measurement of the optical attenuation coefficient and the scattering anisotropy parameter based on applying the extended Huygens-Fresnel principle to optical coherence tomography images of blood is demonstrated. The images are acquired with a low-power probing beam at the wavelength of 1300 nm. Values of 12.15 mm−1 and 0.95 are found for the total attenuation coefficient and the scattering anisotropy factor, respectively. Also, as a preliminary step, the optical refraction index is determined with a precision of two decimal numbers directly from optical coherence images. The total attenuation coefficient and the scattering anisotropy factor are determined with precisions within experimental error margins of 5% and 2%, respectively. Readable OCT signal is obtained for a maximum propagation of light into blood of 0.25 mm. At the maximum probed depth, the measured signal is almost 103 smaller than its initial intensity when entering the sample.

  9. Automatic segmentation of coronary morphology using transmittance-based lumen intensity-enhanced intravascular optical coherence tomography images and applying a localized level-set-based active contour method.

    Science.gov (United States)

    Joseph, Shiju; Adnan, Asif; Adlam, David

    2016-10-01

    Lumen segmentation from clinical intravascular optical coherence tomography (IV-OCT) images has clinical relevance as it provides a full three-dimensional perspective of diseased coronary artery sections. Inaccurate segmentation may occur when there are artifacts in the image, resulting from issues such as inadequate blood clearance. This study proposes a transmittance-based lumen intensity enhancement method that ensures only lumen regions are highlighted. A level-set-based active contour method that utilizes the local speckle distribution properties of the image is then employed to drive an image-specific active contour toward the true lumen boundaries. By utilizing local speckle properties, the intensity variation issues within the image are resolved. This combined approach has been successfully applied to challenging clinical IV-OCT datasets that contains multiple lumens, residual blood flow, and its shadowing artifact. A method to identify the guide-wire and interpolate the lost lumen segments has been implemented. This approach is fast and can be performed even when guide-wire boundaries are not easily identified. Lumen enhancement also makes it easy to identify vessel side branches. This automated approach is not only able to extract the arterial lumen, but also the smaller microvascular lumens that are associated with the vasa vasorum and with atherosclerotic plaque.

  10. Computerized Interactive Gaming via Supporting Vector Machines

    OpenAIRE

    Jiang, Yang; Jiang, Jianmin; Palmer, Ian

    2008-01-01

    Computerized interactive gaming requires automatic processing of large volume of random data produced by players on spot, such as shooting, football kicking, and boxing. This paper describes a supporting vector machine-based artificial intelligence algorithm as one of the possible solutions to the problem of random data processing and the provision of interactive indication for further actions. In comparison with existing techniques, such as rule-based and neural networks, and so forth, our S...

  11. Computerized flow monitors detect small kicks

    Energy Technology Data Exchange (ETDEWEB)

    McCann, D.; White, D. (Sedco Forex, Paris (FR))

    1992-02-24

    This paper reports on a smart alarm system installed on a number of offshore rigs and one land rig which can detect kicks more quickly than conventional systems. This rapid kick detection improves rig safety because the smaller the detected influx, the easier it is to control the well. The extensive computerized monitoring system helps drilling personnel detect fluid influxes and fluid losses before the changes in flow would normally be apparent.

  12. The Future of Computerized Decision Making

    Science.gov (United States)

    2014-12-01

    available in digital form -- data such as newspaper articles, video, and books -- and can be searched according to topics and keywords , or sounds and...away from using observational or model- driven data to inform their decisions. At the same time, enhancements to methods for rapidly creating, merging...themselves---and that we need automated ways of reoptimizing as these metamodels evolve over time. Causal computerized decision making: As I discuss

  13. Errors associated with outpatient computerized prescribing systems

    Science.gov (United States)

    Rothschild, Jeffrey M; Salzberg, Claudia; Keohane, Carol A; Zigmont, Katherine; Devita, Jim; Gandhi, Tejal K; Dalal, Anuj K; Bates, David W; Poon, Eric G

    2011-01-01

    Objective To report the frequency, types, and causes of errors associated with outpatient computer-generated prescriptions, and to develop a framework to classify these errors to determine which strategies have greatest potential for preventing them. Materials and methods This is a retrospective cohort study of 3850 computer-generated prescriptions received by a commercial outpatient pharmacy chain across three states over 4 weeks in 2008. A clinician panel reviewed the prescriptions using a previously described method to identify and classify medication errors. Primary outcomes were the incidence of medication errors; potential adverse drug events, defined as errors with potential for harm; and rate of prescribing errors by error type and by prescribing system. Results Of 3850 prescriptions, 452 (11.7%) contained 466 total errors, of which 163 (35.0%) were considered potential adverse drug events. Error rates varied by computerized prescribing system, from 5.1% to 37.5%. The most common error was omitted information (60.7% of all errors). Discussion About one in 10 computer-generated prescriptions included at least one error, of which a third had potential for harm. This is consistent with the literature on manual handwritten prescription error rates. The number, type, and severity of errors varied by computerized prescribing system, suggesting that some systems may be better at preventing errors than others. Conclusions Implementing a computerized prescribing system without comprehensive functionality and processes in place to ensure meaningful system use does not decrease medication errors. The authors offer targeted recommendations on improving computerized prescribing systems to prevent errors. PMID:21715428

  14. Changing to computerized documentation--plus!

    Science.gov (United States)

    Town, J

    1993-07-01

    A recent change to a computerized documentation system has had a positive influence on productivity, reliability of documentation, quality assurance, nurse satisfaction and professional practice. This software system combines the care plan and nurses' notes and is standard-based. Each patient's care plan is compiled from Units of Care, which provide a menu covering nursing diagnosis, medical diagnosis, chief complaints and special procedures and events.

  15. Computerized analysis of the smile in Orthodontics

    Directory of Open Access Journals (Sweden)

    Luiz Vicente de Moura LOPES

    2006-05-01

    Full Text Available In most cases the search for orthodontic treatment is related withesthetics cause. Nowadays, a beautiful smile is extremely importantfor the society. Establishing elements for diagnosis and planning,looking at a harmonious and well-balanced smile became an obligation at dentistry offices. The esthetics is evaluated by the outline of the bone tissues and its relation with the soft tissues. A good way to get this evaluation is using photographs. The purpose of this research was to analyze computer standard pictures of the maximum smile, as complement to the orthodontic documentation to help not only in the diagnostic and planning but also in the valuation of obtained results. Standard pictures of the maximum smile were obtained in the natural position of the head. Linear,angular and proportional measures were evaluated through the computerized program (CEFX2001 – CDT. The sample consisted of 28 patients, white, male, age between 19 and 25 years old, with Class I occlusion and no previous orthodontic treatment. The values of the descriptive statistics and error analysis were obtained. The results were compared with the values found in the literature, and the values found at a study using the same computerized program CEFX2001 – CDT, but with female patients. The final results were similar to the values found in the literature and the values found in a study using the same computerized program CEFX2001 – CDT,but with female patients.

  16. Computerized implant-dentistry: Advances toward automation

    Science.gov (United States)

    Gulati, Minkle; Anand, Vishal; Salaria, Sanjeev Kumar; Jain, Nikil; Gupta, Shilpi

    2015-01-01

    Advancements in the field of implantology such as three-dimensional imaging, implant-planning software, computer-aided-design/computer-aided-manufacturing (CAD/CAM) technology, computer-guided, and navigated implant surgery have led to the computerization of implant-dentistry. This three-dimensional computer-generated implant-planning and surgery has not only enabled accurate preoperative evaluation of the anatomic limitations but has also facilitated preoperative planning of implant positions along with virtual implant placement and subsequently transferring the virtual treatment plans onto the surgical phase via static (guided) or dynamic (navigated) systems aided by CAD/CAM technology. Computerized-implant-dentistry being highly predictable and minimally invasive in nature has also allowed implant placement in patients with medical comorbidities (e.g. radiation therapy, blood dyscrasias), in patients with complex problems following a significant alteration of the bony anatomy as a result of benign or malignant pathology of the jaws or trauma and in patients with other physical and emotional problems. With significant achievements accomplished in the field of computerized implant-dentistry, attempts are now been made toward complete automation of implant-dentistry. PMID:25810585

  17. Computerized implant-dentistry: Advances toward automation

    Directory of Open Access Journals (Sweden)

    Minkle Gulati

    2015-01-01

    Full Text Available Advancements in the field of implantology such as three-dimensional imaging, implant-planning software, computer-aided-design/computer-aided-manufacturing (CAD/CAM technology, computer-guided, and navigated implant surgery have led to the computerization of implant-dentistry. This three-dimensional computer-generated implant-planning and surgery has not only enabled accurate preoperative evaluation of the anatomic limitations but has also facilitated preoperative planning of implant positions along with virtual implant placement and subsequently transferring the virtual treatment plans onto the surgical phase via static (guided or dynamic (navigated systems aided by CAD/CAM technology. Computerized-implant-dentistry being highly predictable and minimally invasive in nature has also allowed implant placement in patients with medical comorbidities (e.g. radiation therapy, blood dyscrasias, in patients with complex problems following a significant alteration of the bony anatomy as a result of benign or malignant pathology of the jaws or trauma and in patients with other physical and emotional problems. With significant achievements accomplished in the field of computerized implant-dentistry, attempts are now been made toward complete automation of implant-dentistry.

  18. Resting state rCBF mapping with single-photon emission tomography and positron emission tomography: magnitude and origin of differences

    Energy Technology Data Exchange (ETDEWEB)

    Jonsson, C.; Kimiaei, S.; Larsson, S.A. [Section of Nuclear Medicine, Department of Hospital Physics, Karolinska Hospital and Department of Medical Radiation Physics, Stockholm University, Stockholm (Sweden); Pagani, M. [Institute of Experimental Medicine, CNR, Rome (Italy); Ingvar, M. [Section of Cognitive Neurophysiology, Karolinska Hospital, Stockholm (Sweden); Thurfjell, L. [Center of Image Analysis, Uppsala University, Uppsala (Sweden); Jacobsson, H. [Department of Diagnostic Radiology, Karolinska Hospital, Stockholm (Sweden)

    1998-02-01

    Single-photon emission tomography (SPET), using technetium-99m hexamethylpropylene amine oxime, and positron emission tomography (PET), using oxygen-15 butanol were compared in six healthy male volunteers with regard to the mapping of resting state regional cerebral blood flow (rCBF). A computerized brain atlas was utilized for 3D regional analyses and comparison of 64 selected and normalized volumes of interest (VOIs). The normalized mean rCBF values in SPET, as compared to PET, were higher in most of the Brodmann areas in the frontal and parietal lobes (4.8% and 8.7% respectively). The average differences were small in the temporal (2.3%) and occipital (1.1%) lobes. PET values were clearly higher in small VOIs like the thalamus (12.3%), hippocampus (12.3%) and basal ganglia (9.9%). A resolution phantom study showed that the in-plane SPET/PET system resolution was 11.0/7.5 mm. In conclusion, SPET and PET data demonstrated a fairly good agreement despite the superior spatial resolution of PET. The differences between SPET and PET rCBF are mainly due to physiological and physical factors, the data processing, normalization and co-registration methods. In order to further improve mapping of rCBF with SPET it is imperative not only to improve the spatial resolution but also to apply accurate correction techniques for scatter, attenuation and non-linear extraction. (orig.) With 6 figs., 3 tabs., 23 refs.

  19. X-Ray Multimodal Tomography Using Speckle-Vector Tracking

    OpenAIRE

    Berujon, Sebastien; Ziegler, Eric

    2015-01-01

    We demonstrate computerized tomography (CT) reconstructions from absorption, phase and dark-field signals obtained from scans acquired when the x-ray probe light is modulated with speckle. Two different interlaced schemes are proposed to reduce the number of sample exposures. First, the already demonstrated x-ray speckle-vector tracking (XSVT) concept for projection imaging allows the three signal CT reconstructions from multiple images per projection. Second, a modified XSVT approach is show...

  20. Polychromatic diffraction contrast tomography

    Energy Technology Data Exchange (ETDEWEB)

    King, A., E-mail: king@synchrotron-soleil.fr [Synchrotron SOLEIL, Gif-sur-Yvette 91192 (France); Reischig, P. [Xnovo Technology ApS, 4600 Køge (Denmark); Department of Materials Science and Engineering, Delft University of Technology, Delft 2628 CD (Netherlands); Adrien, J. [MATEIS, INSA de Lyon, Villeurbanne 69621 (France); Peetermans, S. [Paul Scherrer Institut, CH-5232 Villigen (Switzerland); Ludwig, W. [MATEIS, INSA de Lyon, Villeurbanne 69621 (France); European Synchrotron Radiation Facility, Grenoble 38043 (France)

    2014-11-15

    This tutorial review introduces the use of polychromatic radiation for 3D grain mapping using X-ray diffraction contrast tomography. The objective is to produce a 3D map of the grain shapes and orientations within a bulk, millimeter-sized polycrystalline sample. The use of polychromatic radiation enables the standard synchrotron X-ray technique to be applied in a wider range of contexts: 1) Using laboratory X-ray sources allows a much wider application of the diffraction contrast tomography technique. 2) Neutron sources allow large samples, or samples containing high Z elements to be studied. 3) Applied to synchrotron sources, smaller samples may be treated, or faster measurements may be possible. Challenges and particularities in the data acquisition and processing, and the limitations of the different variants, are discussed. - Highlights: • We present a tutorial review of polychromatic diffraction contrast tomography techniques. • The use of polychromatic radiation allows the standard synchrotron DCT technique to be extended to a range of other sources. • The characteristics and limitations of all variants of the techniques are derived, discussed and compared. • Examples using laboratory X-ray and cold neutron radiation are presented. • Suggestions for the future development of these techniques are presented.

  1. Computerized Information System for Nursing Educators; The First Step Towards Computerized Instruction or Computer Assisted Instruction.

    Science.gov (United States)

    Alvir, Howard P.

    This document outlines the guidelines and procedures for educators interested in using the Computerized Information System for Nursing Educators (CISNE), a project sponsored by Francophone International Learning Module Systems. In the first of the report's four sections are a brief description of CISNE guidelines for entry procedures and forms for…

  2. Computerized acoustical characterization system of medical phantoms

    Science.gov (United States)

    Nazihah, M. D.; Kadri, S.; Yaacob, M. I. H.; Rosly, J.

    2013-05-01

    The development of a computerized acoustical characterization system of medical phantoms is described in this paper. The system employs the insertion technique and it was developed using LabView 2011 where the ultrasound signal was acquired through the interfacing scheme of an oscilloscope to a personal computer. The system performance was validated by comparing measured acoustical properties with values obtained from the previous studies. Other than faster measurement time, the developed system carried percentage difference at less than 1.00% for all of the acoustical properties measurements at 23.0°C to 25.0°C respectively.

  3. Visualization in the age of computerization

    CERN Document Server

    Carusi, Annamaria; Webmoor, Timothy; Woolgar, Steve

    2014-01-01

    Digitalization and computerization are now pervasive in science. This has deep consequences for our understanding of scientific knowledge and of the scientific process, and challenges longstanding assumptions and traditional frameworks of thinking of scientific knowledge. Digital media and computational processes challenge our conception of the way in which perception and cognition work in science, of the objectivity of science, and the nature of scientific objects. They bring about new relationships between science, art and other visual media, and new ways of practicing science and organizing

  4. Computerized documentation systems: blessings or curse?

    Science.gov (United States)

    Vlasses, F R

    1993-01-01

    This article considers the possibility that computerized documentation systems will negatively impact knowledge development in nursing. Ideas from three vantage points is presented. First, systems are being developed from theoretical frameworks that are not necessarily grounded in nursing, and these systems, in turn, influence the nurses's ability to process and conceptualize information. Second, computer systems may support the retrieval of empirical data to the elimination of other types of data necessary to the development of nursing knowledge. Third, computers may decrease opportunities for collegial dialogue. These factors together create an atmosphere of "technologic determinism" (Robinson & Robinson, 1990), which can inhibit the development of new ideas in nursing.

  5. Automatic computerized radiographic identification of cephalometric landmarks.

    Science.gov (United States)

    Rudolph, D J; Sinclair, P M; Coggins, J M

    1998-02-01

    Computerized cephalometric analysis currently requires manual identification of landmark locations. This process is time-consuming and limited in accuracy. The purpose of this study was to develop and test a novel method for automatic computer identification of cephalometric landmarks. Spatial spectroscopy (SS) is a computerized method that identifies image structure on the basis of a convolution of the image with a set of filters followed by a decision method using statistical pattern recognition techniques. By this method, characteristic features are used to recognize anatomic structures. This study compared manual identification on a computer monitor and the SS automatic method for landmark identification on minimum resolution images (0.16 cm2 per pixel). Minimum resolution (defined as the lowest resolution at which a cephalometric structure could be identified) was used to reduce computational time and memory requirements during this development stage of the SS method. Fifteen landmarks were selected on a set of 14 test images. The results showed no statistical difference (p > 0.05) in mean landmark identification errors between manual identification on the computer display and automatic identification using SS. We conclude that SS shows potential for the automatic detection of landmarks, which is an important step in the development of a completely automatic cephalometric analysis.

  6. Compton imaging tomography for nondestructive evaluation of large multilayer aircraft components and structures

    Science.gov (United States)

    Romanov, Volodymyr; Grubsky, Victor; Zahiri, Feraidoon

    2017-02-01

    We present a novel NDT/NDE tool for non-contact, single-sided 3D inspection of aerospace components, based on Compton Imaging Tomography (CIT) technique, which is applicable to large, non-uniform, and/or multilayer structures made of composites or lightweight metals. CIT is based on the registration of Compton-scattered X-rays, and permits the reconstruction of the full 3D (tomographic) image of the inspected objects. Unlike conventional computerized tomography (CT), CIT requires only single-sided access to objects, and therefore can be applied to large structures without their disassembly. The developed tool provides accurate detection, identification, and precise 3D localizations and measurements of any possible internal and surface defects (corrosions, cracks, voids, delaminations, porosity, and inclusions), and also disbonds, core and skin defects, and intrusion of foreign fluids (e.g., fresh and salt water, oil) inside of honeycomb sandwich structures. The NDE capabilities of the system were successfully demonstrated on various aerospace structure samples provided by several major aerospace companies. Such a CIT-based tool can detect and localize individual internal defects with dimensions about 1-2 mm3, and honeycomb disbond defects less than 6 mm by 6 mm area with the variations in the thickness of the adhesive by 100 m. Current maximum scanning speed of aircraft/spacecraft structures is about 5-8 min/ft2 (50-80 min/m2).

  7. Case of cerebral cryptococcosis. Mainly computerized tomographic findings

    Energy Technology Data Exchange (ETDEWEB)

    Yamagami, Tatsuhito; Nomura, Takayoshi; Imagawa, Kenji; Asai, Akira; Kawasaki, Michiro (National Hospital of Nagoya (Japan))

    1984-05-01

    A 66-year-old female was admitted to our hospital with chief complaint of vertigo, gait disturbance and dysarthria. These symptoms started about one year before admission and worsened. Vomiting and urinary incontinence appeared. Neurological examination revealed left cerebellar ataxia and dysarthria. In plain CT (computerized tomography) irregular ill-defined low density area was noted in the cerebellar vermis and bilateral cerebellar hemispheres. And slight ventricular dilatation was found. Irregular shape of ring-like enhancement corresponding to capsule and patchy or mottled enhancement inside the tumor were seen. Suboccipital craniectomy was performed and yellowish necrotic tumor with hard capsule was removed. Histological diagnosis was not neoplasm or tuberculoma. Postoperatively liver function progressively worsened. She died due to disseminated intravascular coagulation. Autopsy revealed typical liver cirrhosis without malignant change. 3.0 x 2.5 cm sized, slightly hard, yellowish lesion was found on upper part of cerebellar hemispheres. This had extremely necrotic tissue and a great number of cryptococcus neoformans were found. And other intracranial lesion was not confirmed. Finding of pulmonary cryptococcosis was not gained. Our case is very rare because of solitary cerebellar abscess and absence of meningitic episode or pulmonary cryptococcosis. There are three types of inflammation in cerebral cryptococcosis. The commonest manifestation is the meningitic type, the second mode is granulomatous lesion and the third and the least presentation is intracranial abscess formation. CT reveals various finidngs according to clinical stage. CT findings are those of meningitis, meningoencephalitis, granuloma and abscess. Cryptococcal granuloma or abscess often simulates brain abscess, glioma and metastatic brain tumor. We discussed CT findings of cerebral cryptococcosis and examined the CT number of our case.

  8. The Reality, Direction, and Future of Computerized Publications

    Science.gov (United States)

    Levenstein, Nicholas

    2012-01-01

    Sharing information in digital form by using a computer is a growing phenomenon. Many universities are making their applications available on computer. More than one hundred and thirty-six universities have developed computerized applications on their own or through a commercial vendor. Universities developed computerized applications in order to…

  9. Health technology assessment review: Computerized glucose regulation in the intensive care unit--how to create artificial control.

    Science.gov (United States)

    Hoekstra, Miriam; Vogelzang, Mathijs; Verbitskiy, Evgeny; Nijsten, Maarten W N

    2009-01-01

    Current care guidelines recommend glucose control (GC) in critically ill patients. To achieve GC, many ICUs have implemented a (nurse-based) protocol on paper. However, such protocols are often complex, time-consuming, and can cause iatrogenic hypoglycemia. Computerized glucose regulation protocols may improve patient safety, efficiency, and nurse compliance. Such computerized clinical decision support systems (Cuss) use more complex logic to provide an insulin infusion rate based on previous blood glucose levels and other parameters. A computerized CDSS for glucose control has the potential to reduce overall workload, reduce the chance of human cognitive failure, and improve glucose control. Several computer-assisted glucose regulation programs have been published recently. In order of increasing complexity, the three main types of algorithms used are computerized flowcharts, Proportional-Integral-Derivative (PID), and Model Predictive Control (MPC). PID is essentially a closed-loop feedback system, whereas MPC models the behavior of glucose and insulin in ICU patients. Although the best approach has not yet been determined, it should be noted that PID controllers are generally thought to be more robust than MPC systems. The computerized Cuss that are most likely to emerge are those that are fully a part of the routine workflow, use patient-specific characteristics and apply variable sampling intervals.

  10. Micro-Layer Tomography System

    Directory of Open Access Journals (Sweden)

    M. Navabpour

    2005-08-01

    Full Text Available Introduction & Background: Tomography or plani-graphy is an x-ray imaging system for preserving a certain plane of a radiography object by diffusing the other planes; however, the desired plane does not obtain an optimum sharpness. Meanwhile, relatively nearer points to the rotating axes fixed point have lesser liner velocity than those lying further from the fixed point. Consequently, unwanted obscuring planes occur gradually, that then render the wanted plane somehow blurred, hence the phenomenon known as "tomographic blurring", which diminishes the clinical value of the image. Thus, computerized imaging is uncertain especially to medical authorities. Besides, there is a possibility of dismissing the lesion in some cases, because of the relatively undesirable deep resolution of the system. The present innovation could be an approach to improve current tomography systems by increasing image resolution, obtaining optimum deep resolution, rapid operation, and cost reduction. Material and Methods: Micro-layer tomography has been designed with the benefit of fast x-ray rotating velocity without tube movement, to make images with deep resolution of millimeter fraction, while there is no need of digital images reconstruction in-struments that allows statistical errors to fall to about zero. Furthermore, high-resolution images could be prepared in all planes, including coronal, sagittal, and transverse ones. Likewise, patient treatment and sys-tem maintenance costs are by far less than those in CT scan and MRI. Results & Conclusion: The system quick operation is highly exceptional; therefore, the tomographic slices could be prepared in about less than 0.02 second. The laboratory samples experienced by this system showed a unique result, suggesting the new device preference.

  11. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Professions Site Index A-Z Computed Tomography (CT) - Head Computed tomography (CT) of the head uses special ... the Head? What is CT Scanning of the Head? Computed tomography, more commonly known as a CT ...

  12. Participatory design for computerization of clinical practice guidelines

    DEFF Research Database (Denmark)

    Lyng, Karen Marie; Pedersen, B. S.

    2011-01-01

    There have been made many attempts on computerization of clinical practice guidelines (CPGs), none have, however achieved any general application in clinical work practice. The objective of this paper is: (1) to raise awareness about the impact the design method used for computerization of CPGs......: PD as a design philosophy, PD as a toolbox and PD as a way to create a shared realm of understanding among IT-designers and health professionals as these are areas of utmost relevance for the design of computerized CPGs. Additionally, the application of PD for computerization of CPGs is illustrated...... by two cases. We conclude that PD is a beneficial approach for design of computerized CPGs. © 2011 Elsevier Inc....

  13. Compressive Phase Contrast Tomography

    CERN Document Server

    Maia, F R N C; Marchesini, S; Padmore, H A; Parkinson, D Y; Pien, J; Schirotzek, A; Yang, C; 10.1117/12.861946

    2010-01-01

    When x-rays penetrate soft matter, their phase changes more rapidly than their amplitude. In- terference effects visible with high brightness sources creates higher contrast, edge enhanced images. When the object is piecewise smooth (made of big blocks of a few components), such higher con- trast datasets have a sparse solution. We apply basis pursuit solvers to improve SNR, remove ring artifacts, reduce the number of views and radiation dose from phase contrast datasets collected at the Hard X-Ray Micro Tomography Beamline at the Advanced Light Source. We report a GPU code for the most computationally intensive task, the gridding and inverse gridding algorithm (non uniform sampled Fourier transform).

  14. Computed tomography:the details.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    2007-07-01

    Computed Tomography (CT) is a well established technique, particularly in medical imaging, but also applied in Synthetic Aperture Radar (SAR) imaging. Basic CT imaging via back-projection is treated in many texts, but often with insufficient detail to appreciate subtleties such as the role of non-uniform sampling densities. Herein are given some details often neglected in many texts.

  15. Computerization of a telescope at secondary education

    Science.gov (United States)

    García Santiago, A.; Martos Jumillas, J.

    2017-03-01

    The work we are presenting in this paper is the computerization of a refractor telescope on an EQ3 type equatorial mount through Arduino. The control of the mount is done via three different interfaces: Stellarium, an Android interface for mobile phones and a second interface for PC made with Processing. The aforementioned work was done by the authors with a double purpose: presenting the interest in astronomy in the Mathematics department, and the development of applications within the subject of Technology in 4th ESO. So, it is a collaborative project between both departments. Except for the telescope and the mount, all the resources we have used can be found in any high school: free software (Guadalinex v9), App Inventor and Processing.The project was carried out under the principle of reducing all possible costs given the economic possibilities of the institution.

  16. Geometric Computing Based on Computerized Descriptive Geometric

    Institute of Scientific and Technical Information of China (English)

    YU Hai-yan; HE Yuan-Jun

    2011-01-01

    Computer-aided Design (CAD), video games and other computer graphic related technology evolves substantial processing to geometric elements. A novel geometric computing method is proposed with the integration of descriptive geometry, math and computer algorithm. Firstly, geometric elements in general position are transformed to a special position in new coordinate system. Then a 3D problem is projected to new coordinate planes. Finally, according to 2D/3D correspondence principle in descriptive geometry, the solution is constructed computerized drawing process with ruler and compasses. In order to make this method a regular operation, a two-level pattern is established. Basic Layer is a set algebraic packaged function including about ten Primary Geometric Functions (PGF) and one projection transformation. In Application Layer, a proper coordinate is established and a sequence of PGFs is sought for to get the final results. Examples illustrate the advantages of our method on dimension reduction, regulatory and visual computing and robustness.

  17. A COMPUTERIZED OPERATOR SUPPORT SYSTEM PROTOTYPE

    Energy Technology Data Exchange (ETDEWEB)

    Thomas A. Ulrich; Roger Lew; Ronald L. Boring; Ken Thomas

    2015-03-01

    A computerized operator support system (COSS) is proposed for use in nuclear power plants to assist control room operators in addressing time-critical plant upsets. A COSS is a collection of technologies to assist operators in monitoring overall plant performance and making timely, informed decisions on appropriate control actions for the projected plant condition. A prototype COSS was developed in order to demonstrate the concept and provide a test bed for further research. The prototype is based on four underlying elements consisting of a digital alarm system, computer-based procedures, piping and instrumentation diagram system representations, and a recommender module for mitigation actions. The initial version of the prototype is now operational at the Idaho National Laboratory using the Human System Simulation Laboratory.

  18. COMPUTERIZED MODEL OF RISK MANAGEMENT IN BUSINESS

    Directory of Open Access Journals (Sweden)

    Petrişor MANDU

    2011-01-01

    Full Text Available The occurrence of risk situation and the manager’s awareness of it are serious threats for the organization and its objectives. Consequently, the manager has to have available, analyze, select and interpret many pieces of information, under stress, before making a decision for avoiding a disaster. Under these circumstances, a computerized model of risk management is the most adequate solution to make the intervention possibilities effective through a quicker and more accurate intervention. The model offers enough confidence and a favorable psychological state for managing risk. In accordance with this model, the risk manager processes the information by means of some operational (mathematical methods and that favors reaching optimum solutions in the shortest delay, based on some estimated anticipations through a rational model.

  19. Sandia computerized shock compression bibliographical database

    Energy Technology Data Exchange (ETDEWEB)

    Wilbeck, J.S.; Anderson, C.E.; Hokanson, J.C.; Asay, J.R.; Grady, D.E.; Graham, R.A.; Kipp, M.E.

    1985-01-01

    A searchable and updateable bibliographical database is being developed which will be designed, controlled, and evaluated by working technical experts in the field of shock-compression science. It will emphasize shock-compression properties in the stress region of a few tens of GPa and provide a broad and complete base of bibliographical information on the shock-compression behavior of materials. Through the operation of technical advisors, the database provides authoritative blbliographical and keyword data for use by both the inexperienced and expert user. In its current form, it consists of: (1) a library of journal articles, reports, books, and symposia papers in the areas of shock physics and shock mechanics; and (2) a computerized database system containing complete bibliographical information, exhaustive keyword descriptions, and author abstracts for each of the documents in the database library.

  20. Neutron tomography

    Science.gov (United States)

    Crump, James C., III; Richards, Wade J.; Shields, Kevin C.

    1995-07-01

    The McClellan Nuclear Radiation Center's (MNRC) staff in conjunction with a Cooperative Research and Development Agreement (CRDA) with the U.C. Santa Barbara facility has developed a system that can be used for aircraft inspection of jet engine blades. The problem was to develop an inspection system that can detect very low concentrations of hydrogen (i.e., greater than 100 ppm) in metal matricies. Specifically in Titanium alloy jet engine blades. Entrapment and precipitation of hydrogen in metals is an undesirable phenomenon which occurs in many alloys of steel and titanium. In general, metals suffer a loss of mechanical properties after long exposures to hydrogen, especially at high temperatures and pressures, thereby becoming embrittled. Neutron radiography has been used as a nondestructive testing technique for many years. Neutrons, because of their unique interactions with materials, are especially useful in the detection of hydrogen. They have an extremely high interaction cross section for low atomic number nuclei (i.e., hydrogen). Thus hydrogen in a metal matrix can be visualized using neutrons. Traditional radiography is sensitive to the total attenuation integrated over the path of radiation through the material. Increased sensitivity and quantitative cross section resolution can be obtained using three-dimensional volumetric imaging techniques such as tomography. The solution used to solve the problem was to develop a neutron tomography system. The neutron source is the McClellan Nuclear Radiation Center's 1 MW TRIGA reactor. This paper describes the hardware used in the system as well as some of the preliminary results.

  1. Applications of tomography in nuclear research

    Energy Technology Data Exchange (ETDEWEB)

    Tanke, R.H.J.; Jaspers, J.E.; Gaalman, P.A.M. (KEMA, Arnhem (Netherlands). Dept. of Chemical Technology and Materials Research); Killian, D. (State Univ. of Utrecht (Netherlands). Buys Ballot Lab.)

    1991-10-01

    Transmission tomography was applied to radioactive waste packages, and emission tomography was applied to fuel rods, fuel elements and as an analysis tool for the determination of the transport of fission products in irradiated UO{sub 2} fuel. An overview of these applications at the KEMA including results hitherto achieved is given. In addition, the theory of tomographic reconstruction in two and three dimensions is shortly described. (orig./HP).

  2. Normalized mean shapes and reference index values for computerized quantitative assessment indices of chest wall deformities

    Science.gov (United States)

    Kim, Ho Chul; Park, Man Sik; Lee, Seong Keon; Nam, Ki Chang; Park, Hyung Joo; Kim, Min Gi; Song, Jae-Jun; Choi, Hyuk

    2015-11-01

    We previously proposed a computerized index (eccentricity index [EI]) for chest-wall deformity measurements, such as pectus excavatum. We sought to define mean shapes based on normal chest walls and to propose for computerized index reference values of that are used in the quantitative analysis of the severity of chest-wall deformities. A total of 584 patients were classified into 18 groups, and a database of their chest-wall computed tomography (CT) scan images was constructed. The boundaries of the chest wall were extracted by using a segmentation algorithm, and the mean shapes were subsequently developed. The reference index values were calculated from the developed mean shapes. Reference index values for the EI were compared with a conventional index, the Haller index (HI). A close association has been shown between the two indices in multiple subjects (r = 0.974, P < 0.001). The newly developed mean shapes and reference index values supply both reliability and objectivity to the diagnosis, analysis, and treatment of chest-wall deformities. They promise to be highly useful in clinical settings.

  3. Three-dimensional computerized selection of hip prostheses in patients with congenital dislocated hips.

    Science.gov (United States)

    Gelalis, L D; Xenakis, T A; Hantes, M; Vartziotis, K; Soucacos, P N

    2001-11-01

    This study assessed the effectiveness of the combined use of computed tomography (CT) and computer-aided design (CAD) in the preoperative evaluation and implant selection in 20 patients (20 hips) with congenital dislocation of the hip who were scheduled to undergo total hip arthroplasty. Computerized selection of the femoral implant with optimum fit and fill was made after a three-dimensional reconstruction of the femoral canal using CT data and CAD. Implantation of all sizes of 5 noncemented and 2 cemented femoral implants was simulated using CATIA software (IBM, Kingstone, NY). When patients underwent surgery, 18 of 20 preselected prostheses agreed by type and size with the prostheses implanted. The remaining 2 preselected implants agreed by type only. In patients with dislocated and dysplastic hips, combined use of CT and CAD allows effective preoperative planning by providing the surgeon with vital information about the proximal femoral canal geometry and the possible femoral implant with optimum fit and fill to be used.

  4. Terahertz wide aperture reflection tomography

    Science.gov (United States)

    Pearce, Jeremy; Choi, Hyeokho; Mittleman, Daniel M.; White, Jeff; Zimdars, David

    2005-07-01

    We describe a powerful imaging modality for terahertz (THz) radiation, THz wide aperture reflection tomography (WART). Edge maps of an object's cross section are reconstructed from a series of time-domain reflection measurements at different viewing angles. Each measurement corresponds to a parallel line projection of the object's cross section. The filtered backprojection algorithm is applied to recover the image from the projection data. To our knowledge, this is the first demonstration of a reflection computed tomography technique using electromagnetic waves. We demonstrate the capabilities of THz WART by imaging the cross sections of two test objects.

  5. Problems and Solutions of Popularization of Accounting Computerization

    Science.gov (United States)

    Lu, Kan; Fu, YingLi; Gu, CaiDong; Zhang, Liang

    With the integration of China's economy and international markets, accounting computerization, which conducts accounting and accounting control by taking advantage of computer, has become a major component sector of accounting modernization and the main content of accounting reform. The popularization of accounting computerization is beyond question. Only this popularization can meet the requirement of knowledge economy for accounting information. It is the need to deepen accounting reform, to further enhance the level of accounting work and to achieve China's modernization of science and technology as well. This paper discusses problems and relevant solutions in the popularization process of accounting computerization so as to carry out this popularization better.

  6. Examination of funnel chests by X-ray and nuclear magnetic resonance tomography: First results and experiences

    Energy Technology Data Exchange (ETDEWEB)

    Raithel, H.J.; Hartung, M.; Gruennewig, B.; Willital, G.

    1983-01-01

    Funnel chest (pectus excavatum) is a congenital malformation of the thorax. Operative correction must presently be regarded as the treatment of choise. In addition to cosmetical and psychological reasons, there are mainly functional aspects justifying a surgery. The indication for surgery results mostly from the objective clinical-diagnostical findings. This article describes the efficiency of both X-ray computerized tomography and also nuclear magnetic resonance tomography (NMR-CAT) which has only recently been introduced to clinical diagnostics.

  7. A new Brief computerized cognitive screening battery (CompCogs for early diagnosis of Alzheimer's disease

    Directory of Open Access Journals (Sweden)

    Helenice Charchat Fichman

    Full Text Available Abstract Screening tests for early diagnosis of dementia are of great clinical relevance. The ideal test set must be brief and reliable, and should probe cognitive components impaired in Alzheimer's disease (AD. Objectives: To develop a new Computerized Cognitive Screening test (CompCogs, and to investigate its validity for the early diagnosis of AD, and evaluate its heuristic value in understanding the processing of information in AD. Methods: The computerized neuropsychological performance battery, originally including six tests, was applied in forty seven patients with probable mild AD and 97 controls matched for age and education. This computerized neuropsychological test battery, developed with MEL Professional, allows control of timing and order of stimuli presentation, as well as recording of response type and latency. A brief-screening version, CompCogs, was selected using the most discriminative neuropsychological test variables derived from logistic regression analysis. Full battery administration lasted about 40 minutes, while the CompCogs took only 15 minutes. Results: CompCogs included the Face test (correct response and Word and Forms with Short term memory tests (reaction time. CompCogs presented 91.8% sensitivity and 93.6% specificity for the diagnosis of AD using ROC analyses of AD diagnosis probability derived by logistic regression. Conclusions: CompCogs showed high validity for AD early diagnosis and, therefore, may be a useful alternative screening instrument.

  8. A statistical model for interpreting computerized dynamic posturography data

    Science.gov (United States)

    Feiveson, Alan H.; Metter, E. Jeffrey; Paloski, William H.

    2002-01-01

    Computerized dynamic posturography (CDP) is widely used for assessment of altered balance control. CDP trials are quantified using the equilibrium score (ES), which ranges from zero to 100, as a decreasing function of peak sway angle. The problem of how best to model and analyze ESs from a controlled study is considered. The ES often exhibits a skewed distribution in repeated trials, which can lead to incorrect inference when applying standard regression or analysis of variance models. Furthermore, CDP trials are terminated when a patient loses balance. In these situations, the ES is not observable, but is assigned the lowest possible score--zero. As a result, the response variable has a mixed discrete-continuous distribution, further compromising inference obtained by standard statistical methods. Here, we develop alternative methodology for analyzing ESs under a stochastic model extending the ES to a continuous latent random variable that always exists, but is unobserved in the event of a fall. Loss of balance occurs conditionally, with probability depending on the realized latent ES. After fitting the model by a form of quasi-maximum-likelihood, one may perform statistical inference to assess the effects of explanatory variables. An example is provided, using data from the NIH/NIA Baltimore Longitudinal Study on Aging.

  9. Computerized mouse pupil size measurement for pupillary light reflex analysis.

    Science.gov (United States)

    Lu, Wei; Tan, Jinglu; Zhang, Keqing; Lei, Bo

    2008-06-01

    Accurate measurement of pupil size is essential for pupillary light reflex (PLR) analysis in clinical diagnosis and vision research. Low pupil-iris contrast, corneal reflection, artifacts and noises in infrared eye imaging pose challenges for automated pupil detection and measurement. This paper describes a computerized method for pupil detection or identification. After segmentation by a region-growing algorithm, pupils are detected by an iterative randomized Hough transform (IRHT) with an elliptical model. The IRHT iteratively suppresses the effects of extraneous structures and noise, yielding reliable measurements. Experimental results with 72 images showed a mean absolute difference of 3.84% between computerized and manual measurements. The inter-run variation for the computerized method (1.24%) was much smaller than the inter-observer variation for the manual method (7.45%), suggesting a higher level of consistency of the former. The computerized method could facilitate PLR analysis and other non-invasive functional tests that require pupil size measurements.

  10. Computerized adaptive testing--ready for ambulatory monitoring?

    DEFF Research Database (Denmark)

    Rose, Matthias; Bjørner, Jakob; Fischer, Felix

    2012-01-01

    Computerized adaptive tests (CATs) have abundant theoretical advantages over established static instruments, which could improve ambulatory monitoring of patient-reported outcomes (PROs). However, an empirical demonstration of their practical benefits is warranted....

  11. Journal of EEA, Vol. 30, 2013 COMPUTERIZED FACILITIES ...

    African Journals Online (AJOL)

    dell

    30, 2013. COMPUTERIZED FACILITIES LAYOUT DESIGN ... School of Mechanical and Industrial Engineering. Addis Ababa ... layout while algorithms such as CORELAP are used to build new ..... Facilities Planning: Layout Optimization.

  12. Computerized Staffing and Scheduling of PRN Nursing Personnel

    OpenAIRE

    Veranth, Martha M; Cheson, Christine

    1984-01-01

    A computerized system developed at LDS Hospital in Salt Lake City, Utah for staffing and scheduling PRN nursing personnel is described. Pre- and post-implementation staffing and scheduling activities are compared.

  13. Diffractive molecular-orbital tomography

    Science.gov (United States)

    Zhai, Chunyang; Zhu, Xiaosong; Lan, Pengfei; Wang, Feng; He, Lixin; Shi, Wenjing; Li, Yang; Li, Min; Zhang, Qingbin; Lu, Peixiang

    2017-03-01

    High-order-harmonic generation in the interaction of femtosecond lasers with atoms and molecules opens the path to molecular-orbital tomography and to probe the electronic dynamics with attosecond-Ångström resolutions. Molecular-orbital tomography requires both the amplitude and phase of the high-order harmonics. Yet the measurement of phases requires sophisticated techniques and represents formidable challenges at present. Here we report a scheme, called diffractive molecular-orbital tomography, to retrieve the molecular orbital solely from the amplitude of high-order harmonics without measuring any phase information. We have applied this method to image the molecular orbitals of N2, CO2, and C2H2 . The retrieved orbital is further improved by taking account the correction of Coulomb potential. The diffractive molecular-orbital tomography scheme, removing the roadblock of phase measurement, significantly simplifies the molecular-orbital tomography procedure and paves an efficient and robust way to the imaging of more complex molecules.

  14. Monte Carlo Simulation Of Emission Tomography And Other Medical Imaging Techniques.

    Science.gov (United States)

    Harrison, Robert L

    2010-01-05

    An introduction to Monte Carlo simulation of emission tomography. This paper reviews the history and principles of Monte Carlo simulation, then applies these principles to emission tomography using the public domain simulation package SimSET (a Simulation System for Emission Tomography) as an example. Finally, the paper discusses how the methods are modified for X-ray computed tomography and radiotherapy simulations.

  15. Detection of tumoral lesions in the posterior fossa, in brain computerized tomography scans for various conditions of acquiring a preliminary approach; Deteccion de lesiones tumorales en fosa posterior en imagenes de Tomografia Computarizada cerebral para diversas condiciones de adquisicion: un enfoque preliminar

    Energy Technology Data Exchange (ETDEWEB)

    Perez, M.; Carvalho-Filho, A. E.; Khoury, H. J.; Casas, M. C.; Andrade, M. E.; Paz, J. E.

    2010-07-01

    The present work performs a study over 13 tomographic images, using an anthropomorphic head phantom. It contains small lesions in the posterior fossa. Tube current (I [mA]), slice thickness (E [mm]), were the parameters changed among studies, looking for the best acquisition conditions, which permit good lesion detectability, and applying the lowest dose. Air Kerma in air [mGy] was calculated. Image quality was analyzed by both expert criterion and some merit figures. Two of them were global: contrasts to noise ratio (RCR [dB]) and signal to noise ratio (RSR). The rest of the measures used were relatives to the maximum dose condition: The gain in signal to noise ratio (SNR [dB]) and the maximum signal to noise ratio (PSNR [dB]), the normalized mean squared error (NMSE) and the structural similarity index (SSIM). Objective and subjective results were correlated. It is shown that it is possible to reduce the dose using lower values of mAs without affecting lesion detectability and keeping good image quality for the scanner used. An optimized protocol is also proposed for the technology used. (Author) 27 refs.

  16. Stratification of mammographic computerized analysis by BI-RADS categories

    Energy Technology Data Exchange (ETDEWEB)

    Lederman, Richard [Department of Radiology, Hadassah University Hospital, Ein Kerem, Jerusalem (Israel); Leichter, Isaac [Department of Electro-Optics, Jerusalem College of Technology, P.O.B. 16031, Jerusalem (Israel); Buchbinder, Shalom [Department of Radiology of The Montefiore Medical Center, The University Hospital for the Albert Einstein College of Medicine, Bronx, New York (United States); Novak, Boris [Department of Applied Mathematics, Jerusalem College of Technology, P.O.B. 16031, Jerusalem 91160 (Israel); Bamberger, Philippe [Department of Electronics, Jerusalem College of Technology, POB 16031, Jerusalem (Israel); Fields, Scott [Department of Radiology, Hadassah University Hospital, Mt. Scopus, Jerusalem (Israel)

    2003-02-01

    The Breast Imaging Reporting and Data System (BI-RADS) was implemented to standardize characterization of mammographic findings. The purpose of the present study was to evaluate in which BI-RADS categories the changes recommended by computerized mammographic analysis are most beneficial. Archival cases including, 170 masses (101 malignant, 69 benign) and 63 clusters of microcalcifications (MCs; 36 malignant, 27 benign), were evaluated retrospectively, using the BI-RADS categories, by several radiologists, blinded to the pathology results. A computerized system then automatically extracted from the digitized mammogram features characterizing mammographic lesions, which were used to classify the lesions. The results of the computerized classification scheme were compared, by receiver operating characteristics (ROC) analysis, to the conventional interpretation. In the ''low probability of malignancy group'' (excluding BI-RADS categories 4 and 5), computerized analysis improved the A{sub z}of the ROC curve significantly, from 0.57 to 0.89. In the ''high probability of malignancy group'' (mostly category 5) the computerized analysis yielded an ROC curve with an A {sub z}of 0.99. In the ''intermediate probability of malignancy group'' computerized analysis improved the A {sub z}significantly, from 0.66 for to 0.83. Pair-wise analysis showed that in the latter group the modifications resulting from computerized analysis were correct in 83% of cases. Computerized analysis has the ability to improve the performance of the radiologists exactly in the BI-RADS categories with the greatest difficulties in arriving at a correct diagnosis. It increased the performance significantly in the problematic group of ''intermediate probability of malignancy'' and pinpointed all the cases with missed cancers in the ''low probability'' group. (orig.)

  17. Vascular injuries in intestinal obstruction. The role of computed tomography; Complicazioni vascolari nelle occlusioni intestinali: ruolo della tomografia computerizzata

    Energy Technology Data Exchange (ETDEWEB)

    Vinci, R.; Angelelli, G.; Stabile Ianora, A.A.; Gaballo, A.; Rotondo, A. [Bari Univ., Bari (Italy). Dipt. di Medicina Interna e Medicina Pubblica, Serv. di Diagnostica per Immagini

    1999-09-01

    The paper investigates computerized tomography capabilities in showing vascular complications secondary to intestinal obstruction and for assessing the site and cause of obstruction. [Italian] Scopo del lavoro e' lo studio dell'uso della tomografia computerizzata nel riconoscimento di complicanze vascolari secondarie ad occlusione intestinale e della presenza, della natura e della sede dell'ostacolo alla canalizzazione intestinale.

  18. Computerized craniofacial reconstruction: Conceptual framework and review.

    Science.gov (United States)

    Claes, Peter; Vandermeulen, Dirk; De Greef, Sven; Willems, Guy; Clement, John Gerald; Suetens, Paul

    2010-09-10

    When confronted with a corpse that is unrecognizable due to its state of decomposition, soft-tissue mutilation or incineration, and if no other identification evidence is available, craniofacial reconstruction (CFR) can be a useful tool in the identification of the body. Traditional methods are based on manual reconstruction by physically modelling a face on a skull replica with clay or plasticine. The progress in computer science and the improvement of medical imaging technologies during recent years has had a significant impact on this domain. New, fast, flexible and computer-based objective reconstruction programs are under development. Employing the newer technologies and permanently evaluating the obtained results will hopefully lead to more accurate reconstructions, beneficial to the added value of CFR methods during crime-scene investigations. A general model-based workflow is observed, when analysing computerized CFR techniques today. The main purpose of this paper is to give an overview of existing computer-based CFR methods up to date defined within a common framework using a general taxonomy. The paper will also discuss the various alternatives and problems which arise during the process of designing a CFR program.

  19. Comprehensive computerized medical imaging: interim hypothetical economic evaluation

    Science.gov (United States)

    Warburton, Rebecca N.; Fisher, Paul D.; Nosil, Josip

    1990-08-01

    The 422-bed Victoria General Hospital (VGH) and Siemens Electric Limited have since 1983 been piloting the implementation of comprehensive computerized medical imaging, including digital acquisition of diagnostic images, in British Columbia. Although full PACS is not yet in place at VGH, experience to date habeen used to project annual cost figures (including capital replacement) for a fully-computerized department. The resulting economic evaluation has been labelled hypothetical to emphasize that some key cost components were estimated rather than observed; this paper presents updated cost figures based on recent revisions to proposed departmental equipment configuration which raised the cost of conventional imaging equipment by 0.3 million* and lowered the cost of computerized imaging equipment by 0.8 million. Compared with conventional diagnostic imaging, computerized imaging appears to raise overall annual costs at VGH by nearly 0.7 million, or 11.6%; this is more favourable than the previous results, which indicated extra annual costs of 1 million (16.9%). Sensitivity analysis still indicates that all reasonable changes in the underlying assumptions result in higher costs for computerized imaging than for conventional imaging. Computerized imaging offers lower radiation exposure to patients, shorter waiting times, and other potential advantages, but as yet the price of obtaining these benefits remains substantial.

  20. Nursing medication administration and workflow using computerized physician order entry.

    Science.gov (United States)

    Tschannen, Dana; Talsma, Akkeneel; Reinemeyer, Nicholas; Belt, Christine; Schoville, Rhonda

    2011-07-01

    The benefits of computerized physician order entry systems have been described widely; however, the impact of computerized physician order entry on nursing workflow and its potential for error are unclear. The purpose of this study was to determine the impact of a computerized physician order entry system on nursing workflow. Using an exploratory design, nurses employed on an adult ICU (n = 36) and a general pediatric unit (n = 50) involved in computerized physician order entry-based medication delivery were observed. Nurses were also asked questions regarding the impact of computerized physician order entry on nursing workflow. Observations revealed total time required for administering medications averaged 8.45 minutes in the ICU and 9.93 minutes in the pediatric unit. Several additional steps were required in the process for pediatric patients, including preparing the medications and communicating with patients and family, which resulted in greater time associated with the delivery of medications. Frequent barriers to workflow were noted by nurses across settings, including system issues (ie, inefficient medication reconciliation processes, long order sets requiring more time to determine medication dosage), less frequent interaction between the healthcare team, and greater use of informal communication modes. Areas for nursing workflow improvement include (1) medication reconciliation/order duplication, (2) strategies to improve communication, and (3) evaluation of the impact of computerized physician order entry on practice standards.

  1. Computed tomography of tuberculous meningitis

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Noriko; Sato, Hiromi; Kawaguchi, Tetsuro; Fujita, Katsuzo; Tanaka, Makoto (Kobe Univ. (Japan). School of Medicine)

    1982-12-01

    Recently, tuberculous meningitis has become rather rare except in areas where tuberculosis is still endemic. Six adolescents and young adults with tuberculous meningitis were evaluated by means of serial computerized tomography (CT), and the results were correlated with the findings of surgical specimens or autopsies. All cases showed meningeal irritation and fever at onset. CSF cultures revealed the presence of tuberculous bacilli. Four cases advanced rapidly to the clinical stage III and expired in a short period-between two weeks to one month from onset. On initial CT scanning, the disappearance of the basal cistern was a characteristic finding in all these cases. With the progression, an enhancement of the basal cistern on contrast injection, a localized hypodensity in adjacent parenchyma, and symmetrical ventricular dilatation appeared. Two autopsied cases showed tuberculous granulomas with purulent materials, thickened meninges, and caseous necrosis in the parenchyma around the basal cistern. The other two cases progressed rather slowly. CT findings at Stage II showed multiple enhanced spots in the basal subcortical area following contrast injection. Tuberculous granulomas were identified in these parts by means of explorative craniotomy. The authors point out the pathognomonic CT findings of tuberculous meningitis and emphasize the necessity of serial CT for the early detection and management of tuberculous meningitis.

  2. Advances in neutron tomography

    Indian Academy of Sciences (India)

    W Treimer

    2008-11-01

    In the last decade neutron radiography (NR) and tomography (NCT) have experienced a number of improvements, due to the well-known properties of neutrons interacting with matter, i.e. the low attenuation by many materials, the strong attenuation by hydrogenous constituent in samples, the wavelength-dependent attenuation in the neighbourhood of Bragg edges and due to better 2D neutron detectors. So NR and NCT were improved by sophisticated techniques that are based on the attenuation of neutrons or on phase changes of the associated neutron waves if they pass through structured materials. Up to now the interaction of the neutron spin with magnetic fields in samples has not been applied to imaging techniques despite the fact that it was proposed many years ago. About ten years ago neutron depolarization as imaging signal for neutron radiography or tomography was demonstrated and in principle it works. Now one can present much improved test experiments using polarized neutrons for radiographic imaging. For this purpose the CONRAD instrument of the HMI was equipped with polarizing and analysing benders very similar to conventional scattering experiments using polarized neutrons. Magnetic fields in different coils and in samples (superconductors) at low temperatures could be visualized. In this lecture a summary about standard signals (attenuation) and the more `sophisticated' imaging signals as refraction, small angle scattering and polarized neutrons will be given.

  3. Computerized knowledge bases in primary health care: a curse or a blessing for health promotion, prevention and patient quality?.

    Science.gov (United States)

    Alendahl, K; Timpka, T; Sjöberg, C

    1995-01-01

    This paper presents a future scenario analysis of how the introduction of computerized knowledge bases (KBs) can come to affect primary care practice. For the collection and analysis of data, a two-level video method was applied. First, four consultations where a computerized KB was used were video-recorded. A search workshop was then carried out by letting a multi-disciplinary panel comment on the video recordings. The comments were categorized with regard to content and perspective. Analyses of the comments showed a concern for a disregard of patients' health beliefs and for difficulties in portioning out the acquired medical knowledge to the patient during the consultation. Furthermore, the computerized KB was found to easily break the natural flow of the consultation and be perceived as a third party. The conclusion is that the most critical aspects for using computerized KBs in a reformed primary health care concern the integration of the systems into the consultation process. Health promotion, prevention, and patient quality are central here, and the introduction of KB technology must not lead the consultation away from these issues.

  4. Upper limb functions regained in quadriplegia: a hybrid computerized neuromuscular stimulation system.

    Science.gov (United States)

    Nathan, R H; Ohry, A

    1990-05-01

    A new, computerized neuromuscular stimulation system was applied to the upper limbs of two patients with complete quadriplegia below the C4 level. The stimulation-generated movements were integrated and augmented by residual, voluntary shoulder girdle movements and mechanical splinting. Up to 12 muscles were stimulated individually with high-resolution surface electrodes; coordination and control of the stimulation was effected by microcomputer. Simple vocal commands to the computer triggered preprogrammed hand prehensions, arm motion, and other functions, giving the patient complete control over the system. In pilot clinical trials of six weeks, writing, eating, and drinking, including picking up and replacing the pen or cup, were achieved.

  5. Instruction manual for the Wahoo computerized database

    Energy Technology Data Exchange (ETDEWEB)

    Lasota, D.; Watts, K.

    1995-05-01

    As part of our research on the Lisburne Group, we have developed a powerful relational computerized database to accommodate the huge amounts of data generated by our multi-disciplinary research project. The Wahoo database has data files on petrographic data, conodont analyses, locality and sample data, well logs and diagenetic (cement) studies. Chapter 5 is essentially an instruction manual that summarizes some of the unique attributes and operating procedures of the Wahoo database. The main purpose of a database is to allow users to manipulate their data and produce reports and graphs for presentation. We present a variety of data tables in appendices at the end of this report, each encapsulating a small part of the data contained in the Wahoo database. All the data are sorted and listed by map index number and stratigraphic position (depth). The Locality data table (Appendix A) lists of the stratigraphic sections examined in our study. It gives names of study areas, stratigraphic units studied, locality information, and researchers. Most localities are keyed to a geologic map that shows the distribution of the Lisburne Group and location of our sections in ANWR. Petrographic reports (Appendix B) are detailed summaries of data the composition and texture of the Lisburne Group carbonates. The relative abundance of different carbonate grains (allochems) and carbonate texture are listed using symbols that portray data in a format similar to stratigraphic columns. This enables researchers to recognize trends in the evolution of the Lisburne carbonate platform and to check their paleoenvironmental interpretations in a stratigraphic context. Some of the figures in Chapter 1 were made using the Wahoo database.

  6. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... the Sinuses? What is CT (Computed Tomography) of the Sinuses? Computed tomography, more commonly known as a ... of page What are some common uses of the procedure? CT of the sinuses is primarily used ...

  7. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... the limitations of CT of the Sinuses? What is CT (Computed Tomography) of the Sinuses? Computed tomography, ... the body being studied. top of page How is the procedure performed? The technologist begins by positioning ...

  8. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... the Sinuses? What is CT (Computed Tomography) of the Sinuses? Computed tomography, more commonly known as a ... of page What are some common uses of the procedure? CT of the sinuses is primarily used ...

  9. Bistatic SAR tomography: processing and experimental results

    OpenAIRE

    Duque Biarge, Sergio; López Dekker, Francisco J.; Merlano Duncan, Juan Carlos; Mallorquí Franquet, Jordi Joan

    2010-01-01

    This paper presents across-track tomography applied to a bistatic geometry with fixed receivers. This kind of geometry can overcome some of the classical monostatic tomography limitations such as temporal decorrelation and irregular baseline distribution. The Remote Sensing Laboratory (RSLab)of the Universitat Politècnica de Catalunya (UPC) has implemented a SAR Bistatic Receiver for INterferometric Applications,SABRINA, with 4-channels. SABRINA has been used to carry out a bistatic tomogr...

  10. Computerized Design and Generation of Gear Drives With a Localized Bearing Contact and a Low Level of Transmission Errors

    Science.gov (United States)

    Litvin, F.; Chen, J.; Seol, I.; Kim, D.; Lu, J.; Zhao, X.; Handschuh, R.

    1996-01-01

    A general approach developed for the computerized simulation of loaded gear drives is presented. In this paper the methodology used to localize the bearing contact, provide a parabolic function of transmission errors, and simulate meshing and contact of unloaded gear drives is developed. The approach developed is applied to spur and helical gears, spiral bevel gears, face-gear drives, and worm-gear drives with cylindrical worms.

  11. Imaging findings of urinary tuberculosis on computerized tomography versus excretory urography: through 46 confirmed cases.

    Science.gov (United States)

    Sallami, Sataa; Ghariani, Rayfa; Hichri, Amin; Zrayer, Olfa

    2014-12-01

    Imaging findings of urinary tuberculosis (TB) on excretory urography (IVP) and CT have been reported to be nonspecific although CT may provide detailed informations. We performed a retrospective study of patients with proven urinary TB to compare imaging findings on IVP and CT and to make a systemic approach to imaging analysis of urinary TB. Urinary TB was diagnosed in 46 patients who had IVP and CT examinations prior to definitive diagnosis and treatment. They were 30 females and 16 males with a mean age of 43.6 ys. We assessed the presence and frequency of urinary tract calcifications, autonephrectomy, renal parenchymal masses, renal parenchymal scarring, moth-eaten calices, amputated infundibulum, renal parenchymal cavities, hydrocalycosis, hydronephrosis, hydroureter and thick urinary tract walls. CT was most sensitive in detecting any renal parenchyma cavities (p=0.01), hydronephrois (p=0.0005), ureteral stricture (p=0.03) and walls thickening of the renal pelvis / ureter (purinary tract walls were significantly more common on CT than on IVP. Multiple findings on CT were more common and very useful for TB diagnosis. Thus, we recommend CT as the standard exam in patients with suspicion of urinary TB.

  12. [Computerized tomography guided biopsy in the diagnosis of neoplastic and inflammatory lesions of the pelvis].

    Science.gov (United States)

    Rimondi, E; Busacca, M; Moio, A; Molinari, M; Nigrisoli, M; Trentani, F; Trentani, P; Tigani, D

    2001-01-01

    To assess the efficacy of percutaneous CT-guided biopsy in the diagnosis and therapeutic planning of neoplastic and flogistic diseases of the pelvis. From July 1990 to December 1999 193 patients (113 males, 80 females: mean age 49, standard deviation 16) were submitted to CT-guided percutaneous biopsy of the pelvic region; 117 biopsies (61%) were performed at iliac, pubic and ischial segments and 76 (39%) at sacral region; 107 patients were admitted to the hospital and 86 were in clinic. Needles were 8 G (4 mm), 10 to 15 cm long. Approach to pelvic lesions was performed according to the specific site. Lesions of the lateral pelvic region have always been approached through the lateral surgical incision according to Enneking. Lesions of the posterior pelvic region have always been approached by the introduction of the needle along the posterior surgical incision according to Enneking. Lesions of the anterior region have always been approached through the anterior surgical incision according to Enneking. From July 1990 to May 1997 pelvic percutaneous biopsies have been carried out with a CT Sytec 3000. From May 1997 to December 1999 the device was replaced by a High Speed CTi. The introduction of spiral CT allowed reduction of performance mean time from 45 minutes (standard deviation 15) to 30 minutes (standard deviation 10). In 154 patients (80%) we observed a neoplastic, inflammatory or not classified degeneration. In 8 patients (4%) the retrieved material ended to be inadequate for a diagnosis. In 31 patients (16%) no disease was revealed at the histological examination. Such patients with negative histological examination have been kept under clinical and radiological control in the following period in order to verify the manifestation or the presence of an alteration previously not observed. On 31-3-2000 none of them had been submitted to a new percutaneous biopsy of the pelvic region. The overall mean accuracy has been 96% considering the negative patients as really negative. In 5 cases (2.6%) we have had complications represented by pain at the introduction and penetration site of the needle. The choice of the needle, the approach to the lesion and the position of the patient are conditioned by the site of the tumor, its extension, the distance skin-neoplastic disease and by the respect of the incision lines of Enneking, in order not to complicate the job of the orthopaedic surgeon spreading tumoral cells outside the chosen surgical approach. The mean time of the procedure is 30 minutes (standard deviation 10). There are no absolute contraindications to percutaneous biopsy except the suspect or the presence of an hydatideal cyst. The risks have to be compared with those correlated with alternative methods or with the more concerning risk of a missed diagnosis. Complications in the literature range from 0% to 10%, the incidence varying according to the location; pain is the most frequent complication. Altogether the most negative event, although not a true complication, is the retrieval of an inadequate sample: the only drawback of percutaneous biopsy in comparison with incisional biopsy. The accuracy rate of percutaneous biopsy varies in relation to the involved anatomical region, to the pathological process, to the experience of the user, to the amount of the retrieved tissue and to the cooperation of the patient. Our experience shows that, in selected patients, percutaneous biopsy is a virtually safe and almost painless procedure which saves the patient from a surgical procedure in regional or general anestesia as for an incisional biopsy, and allows immediate planning and scheduling of a correct therapy for primitive or secondary neoplastic lesions.

  13. Management of irradiation in helical computerized tomography; Gestion de l'irradiation en tomodensitometrie helicoidale

    Energy Technology Data Exchange (ETDEWEB)

    Cordoliani, Y.S.; Hazebroucq, V.; Aubert, B.; Sarazin, J.L

    1999-10-01

    The helical scanner is actually the most irradiating diagnosis technique. The received doses in the explored volume are from 20 to 30 mGy by series. A reduction of the radiation doses for the patients can be reduced by the choice of the material and its options, by the modifications of acquisition modes (reduction of radiation intensity, step greater than 1), by the use of reconstruction possibilities in the volume, by the optimization of the use of the contrast product. Some practices increase this dose: repetition of the sequences, tilting of the stand of the microscope. (N.C.)

  14. STUDY OF SEIZURE DISORDER IN CHILDREN IN CORRELATION WITH COMPUTERIZED TOMOGRAPHY AND ELECTROENCEPHALOGRAPHY

    Directory of Open Access Journals (Sweden)

    Sidhartha Kiran

    2016-04-01

    Full Text Available BACKGROUND Seizure disorders are fairly common in children. Almost 5% of children at risk of experiencing a seizure. The aetiology of seizures is different in India and other developing countries as compared to the developed world. Tuberculoma and neurocysticercosis have relatively high frequency in India. 1 Most of the Indian studies on seizure disorders were done in mixed population of adults and children. Only few Indian studies looked at the prevalence, incidence, causative factors and other aspects of childhood seizures. The present study emphasizing on clinical profile of seizures concentrating only on paediatric age group and to evaluate the role of EEG and CT scan brain as a diagnostic aid in various seizure disorders in children. This study focusses on CT findings, which are more easily available in peripheries where MRI facilities may not be available, though MRI may be superior to CT in identifying the lesions. STUDY METHODS The study includes 108 children from 1 year to less than 12 years of age with various seizure disorders, who are coming to Paediatric Outpatient and Inpatient Department, Govt. General Hospital, Kakinada, from November 2014 to October 2015. This is a cross sectional observation study. RESULTS Out of the 108 cases studied, half of the patients (n=55, 50.9% presented with GTCS. Complex partial seizures is the second most common type of seizure disorder (n=29, 26.9%. Maximum number of children were in the 3-10 years’ age group (n=65, 60.18%. Maximum number of patients presented during 12th year (n=17, 15.7% followed by 8th year (n=14, 13%. Out of 108 children studied, 70 (64.81% are male children and 38 (35.19% are female children. The male:female ratio is 1.8:1. Among the patients with abnormal CT, solitary tuberculoma was the most frequent abnormality which was detected in 22 patients (40%, Neurocysticercosis was the second common abnormality detected in the present study. Among the patients with abnormal EEG, features suggestive of generalized seizure disorder was present in 39 cases (60.94%. One hemisphere slowing suggestive of underlying focus is present in 25 cases (39.06%, left side being involved in more number of patients than the right side. In the present study among patients with GTCS, EEG abnormality alone was found in 25.45% cases, CT abnormality alone was found in 23.64% cases and both CT and EEG were abnormal in 21.82% cases. CONCLUSION Seizure disorders were found to be more common in male children compared to female children. The male:female ratio is 1.8:1. 2 The incidence of seizure disorders was found to be high in children above 3 years of age. Generalized seizures were more common than partial seizures. Among the generalized seizures, generalized tonic clonic seizures were common and among partial seizures complex partial seizures were common. In the present study, CT scan revealed structural abnormalities more commonly in partial seizures (74% than in generalized seizures (41%. The most common finding observed by CT scan was tuberculoma followed by neurocysticercosis. EEG abnormalities were found in 50% of cases of generalized seizures and 74% of cases of partial seizures.

  15. Cerebral toxoplasmosis in AIDS - computerized tomography evaluation; Toxoplasmose cerebral na SIDA - avaliacao por tomografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Regina Coeli Fonseca [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Hospital Universitario Antonio Pedro. Servico de Radiologia; Narchiori, Edson [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Dept. de Radiologia

    1999-06-01

    Cerebral toxoplasmosis is a disease that affects many AIDS's patients. FOr this paper 46 patients with confirmed cases of cerebral toxoplasmosis who did a CT scan between March, 1994 and September, 1997 were examined. Single lesions were found in 28.3% of the patients. The lesions were more frequently detected in the basal ganglia and the frontal lobes. No lesion was larger than 4 cm. As regards the contrast enhancing of the lesions on a CT scan we observed that 54.5% of the lesions had a ring-like contrast enhancing, 36.4% had a nodular contrast enhancing and 6% had a heterogeneous form. After the 21st day of treatment we noticed an improvement in the aspect of the patients'lesions. The improvement of the lesions could be seen through a reduction of the edematous halo, a reduction of the lesion size and a modification in the contrast enhancing on the CT scan. The CT scan was an important method to demonstrate the lesions compatibility enhancing on the CT scan. The CT scan was an important method to demonstrate the lesions compatibility with cerebral toxoplasmosis, as well as to monitor these patients during treatment. (author)

  16. Assessment of liver volume with spiral computerized tomography scanning: predicting liver volume by age and height

    Directory of Open Access Journals (Sweden)

    Madhu Sharma

    2016-07-01

    Conclusions: Liver volume is a reliable index of liver size and measurement of liver volume with spiral CT is useful method. Spiral CT can be utilized for measurement of liver volume for such purpose. [Int J Res Med Sci 2016; 4(7.000: 3020-3023

  17. Lesions of cartilage in the femoropateliar joint, diagnosis by computerized tomography

    Energy Technology Data Exchange (ETDEWEB)

    Reiser, M.; Anacker, H.; Karpf, P.M.; Hoerterer, H.; Paar, O.; Riel, K.A.

    1982-01-21

    The conventional arthrographic methods for demonstration of the femoro-patellar joint are not sufficiently reliable. Through the use of CT-arthrography a cross-sectional image free of superimposition and possessing a high density resolution is available thus facilitating a direct demonstration of the joint cartilage. Traumatic and degenerative lesions of the cartilage can be clearly shown by CT-arthrography. Damage of cartilage in patients with chondromalacia patellae can be differentiated in its different stages. The shape of the patella and its relation to femoral condyles can be evaluated more accurate than by conventional axial X-rays.

  18. Anatomic considerations for C2 pedicle screw placement: the use of computerized tomography measurements

    OpenAIRE

    Adebukoa Onibokun; Simona Bistazzoni; Marco Sassi; Khoo, Larry T.

    2009-01-01

    OBJECTIVE: more detailed anatomical knowledge of the C2 pedicle is required to optimize and minimize the risk of screw placement. The aim of this study was to evaluate the linear and angular dimensions of the true C2 pedicle using axial CT. METHODS: ninety three patients (47 males, 46 females mean age 48 years) who had cervical spinal CT imaging performed were evaluated for this study. Axial images of the C2 pedicle were selected and the following pedicle parameters were determined: pedicle w...

  19. [Computerized tomography of the brain in diagnosis of neuroinfections--personal observations].

    Science.gov (United States)

    Kepa, L

    An analysis of CT-scans of the brain in 55 patients with suspected neuroinfections is presented. All patients were treated at the I Department of Infectious Diseases of the Silesian Academy of Medicine in 1983-1992. Patients were divided into 3 groups. The first group included patients with suppurative meningitis and encephalitis, the second--with aseptic meningitis, and the third group--patients with other CNS diseases. An analysis has shown that CT-scans of the brain are very useful in an early detection of neuroinfections complications and sequelae, especially brain abscess. The author suggests that CT-scans of the brain may also play an important role in differential diagnosis of neuroinfections and other CNS diseases together with clinical symptoms.

  20. The acute orbit: Differentiation of orbital cellulitis from subperiosteal abscess by computerized tomography

    Energy Technology Data Exchange (ETDEWEB)

    Handler, L.C.; Davey, I.C. (Groote Schuur Hospital, Cape Town (South Africa). Dept. of Neuroradiology Cape Town Univ. (South Africa)); Hill, J.C.; Lauryssen, C. (Groote Schuur Hospital, Cape Town (South Africa). Dept. of Ophthalmology Cape Town Univ. (South Africa))

    1991-02-01

    A series of 65 patients suffering from acute inflammatory disease of the orbit was studied by CT. Ethmoiditis was the cause in the vast majority; trauma and dental extraction played a lesser role in causation. Orbital cellulitis was diagnosed in 17 and subperiosteal abscess in the remaining 48. It was not possible to differentiate 33 pus-containing abscesses from the six with inflammatory masses (phlegmons). The satisfactory response to aggressive medical treatment in those patients with inflammatory masses that were not drained justifies a more conservative approach; surgical drainage being reserved for those with a deterioration in proptosis, ocular movements or vision. Six abscesses arose de novo, of which some were in the orbital fat rather than the subperiosteal space. (orig.).

  1. Regression of nodules on cranial computerized tomography (CCT) scans in 4 focal epileptic patients

    Energy Technology Data Exchange (ETDEWEB)

    Bahk, Yong Whee; Yoon, Sei Chul; Park, Seog Hee; Huh, Choon Woong [Catholic Medical College, Seoul (Korea, Republic of)

    1983-03-15

    Epilepsy can be defined as a paroxysmal, excessive, neuronal discharge within the brain originating from either cortical or sugcortical regions. The incidence of epilepsy is increasing possibly due to the survival of persons who should have died of brain injuries or other cerebral abnormalities acquired in early life. The use of antibiotics and improvement in the medical care have saved many children who might have died of meningitis, brain abscess, encephalitis, severe head injuries, etc. CCT scan is new radiologic procedure for defining cranial and intracranial structures and also an useful procedure for evaluation and follow-up (FU) of patient with focal seizure disorder. Recently we experienced nodules which were isodense or hypodense on initial non contrasted CT (NECT) and scans became hyperdense of the enhancement in 4 cases of focal epileptic seizure. Nearly complete disappearance or regression of the epileptic foci occurred on the FU CT scans in 2 cases. Operation was performed in 2 cases. The tissue specimen obtained from the CT nodule revealed cerebral edema in one case and localized gliosis and congestion in the other. All the patients showed marked clinical improvement when the CT nodule improved. Review of literature failed to disclose any previous report on such observation.

  2. Case of absence of the septum pellucidum accompanied with hydrocephalus and detected by computerized tomography

    Energy Technology Data Exchange (ETDEWEB)

    Tominaga, K.; Kobayashi, E.; Yamamoto, K.; Asakura, T. (Kagoshima Univ. (Japan). Faculty of Medicine)

    1981-06-01

    A case of absence of the septum pellucidum accompanied with hydrocephalus in a 56 year old woman who had complained headache, dizziness and numbness of left leg was reported. Absence of the septum pellucidum in this case had not been detected until CT scan was performed. Ventriculoperitoneal shunt was performed, then her complaints were cleared up. The discussion was limited as far as possible to absence of the septum pellucidum without agenesis of the corpus callosum with a few references. Encephalographic characteristics of absence of the septum pellucidum were first noted by Foster in 1935. The real prevalence should lie at about 1 : 400 in a sufficiently large encephalographical series, which should be an estimate between 2 and 3 per 100,000 of population. Encephalography, although, afflicts patients with headache, nausea and vomiting, moreover it accompanied with possible intracranial infection. On the other hand, CT scan has cleared up these problems, we can perform it easily in many cases, and know about status of the septum pellucidum. Further examination for more distinct information are taken by coronal section and ''high definition 5 mm slice thickness'' of CT scan.

  3. Cystic lymphagioma: diagnostic by ecography and computerized tomography. Hallazgos radiologicos en el linfagioma quistico

    Energy Technology Data Exchange (ETDEWEB)

    Escribano, J.; Zurera, L.J.; Cano, A.; Canis, M.; Delgado, F.; Garcia-Revillo, J.

    1991-01-01

    We present four cases of cystic lymphagioma (CL) confirmed by pathoanatomic tests. The first, cervicothoracic, in a neonate in whom echography raised suspicion of an intrauterine localization. The second, in a male aged 17, right laterocervical, with recurrence in mediastinus. Another one in a woman aged 30 suffering from cervicothoracic and abdominal damage. Finally, another woman aged 36 with pure mediastinal CL. Patients presented with nonspecific symptomatology. Simple radiographies showed well delimited ''water''-dense tumoral masses and in only one case was displacement of mediastinal structures found. By echography CL were observed to have cystic features, with interior septa, By CT it was confirmed that the lesion was well delimited, sometimes enclosed in a capsula and presented low density homogeneous composition. The lesion itself to the neighboring structures rather that displace them. By angiography we could observe that mass was avascular and displaced normal vessels (Author)

  4. Clinical observations of infants with multiple encephalomalacia on cranial computerized tomography

    Energy Technology Data Exchange (ETDEWEB)

    Eda, I.; Yoshino, K.; Nakai, M.; Takashima, S. (Tottori Univ., Yonago (Japan). School of Medicine); Morita, M.

    1982-09-01

    Four cases whose CT scans showed multi-focal or diffuse low density in both cerebral hemisphere were reported and their clinical histories, roentogenographic and electroencephalographic findings were compared. Out of 2 cases with multi-focal low density, one fatal case (Case 1) was diagnosed neuropathologically as multicystic encephalomalacia (MCEM). He had asphyxia at delivery, convulsion and fever for a few days from the first day. Case 2 was one of twins with a clinical history of intrauterine onset. He had no trouble in delivery but poor feedings in the neonatal period. Two cases showed microcephaly, severe psychomotor retardation and tetraplegia later. Two cases with diffuse low density had the episode of respiratory arrest in early infancy. In one patient (Case 3), several cavities in CT and PEG at 2 months of age were demonstrated, and changed into diffuse low density of cerebral hemispheres at 8 months. Case 4 showed almost normal CT at the age of 16 days and developed diffuse low density at 5 months. They also showed microcephaly, severe psychomotor retardation and tetraplegia. EEG showed irregular slow wave activities in 2 cases with multicystic lesions, and almost flat activities in 2 cases with diffuse cystic lesions. The former was compatible with MCEM and the latter hydranencephaly of postnatal onset described by Friede. It was concluded that diffuse cystic lesion could be classified as an extreme type of MCEM, and both destructive lesions caused by pre-or postnatal hypoxia and circulatory disturbances of different severity. Serial CT scans might demonstrate the onset and progression of these pathological changes. EEG was also useful for monitoring the courses of these diseases.

  5. X-ray Multimodal Tomography Using Speckle-Vector Tracking

    Science.gov (United States)

    Berujon, Sebastien; Ziegler, Eric

    2016-04-01

    We demonstrate computerized tomography (CT) reconstructions from absorption, phase, and dark-field signals obtained from scans acquired when the x-ray probe light is modulated with speckle. Two different interlaced schemes are proposed to reduce the number of sample exposures. First, the already demonstrated x-ray speckle-vector tracking (XSVT) concept for projection imaging allows the three signal CT reconstructions from multiple images per projection. Second, a modified XSVT approach is shown to provide absorption and phase reconstructions, this time from a single image per angular projection. Reconstructions from data obtained at a synchrotron facility emphasize the potential of the approaches for the imaging of complex samples.

  6. Computerized comprehensive data analysis of Lung Imaging Database Consortium (LIDC)

    Energy Technology Data Exchange (ETDEWEB)

    Tan Jun; Pu Jiantao; Zheng Bin; Wang Xingwei; Leader, Joseph K. [Department of Radiology, Imaging Research Division, University of Pittsburgh, 3362 Fifth Avenue, Pittsburgh, Pennsylvania 15213 (United States)

    2010-07-15

    Purpose: Lung Image Database Consortium (LIDC) is the largest public CT image database of lung nodules. In this study, the authors present a comprehensive and the most updated analysis of this dynamically growing database under the help of a computerized tool, aiming to assist researchers to optimally use this database for lung cancer related investigations. Methods: The authors developed a computer scheme to automatically match the nodule outlines marked manually by radiologists on CT images. A large variety of characteristics regarding the annotated nodules in the database including volume, spiculation level, elongation, interobserver variability, as well as the intersection of delineated nodule voxels and overlapping ratio between the same nodules marked by different radiologists are automatically calculated and summarized. The scheme was applied to analyze all 157 examinations with complete annotation data currently available in LIDC dataset. Results: The scheme summarizes the statistical distributions of the abovementioned geometric and diagnosis features. Among the 391 nodules, (1) 365 (93.35%) have principal axis length {<=}20 mm; (2) 120, 75, 76, and 120 were marked by one, two, three, and four radiologists, respectively; and (3) 122 (32.48%) have the maximum volume overlapping ratios {>=}80% for the delineations of two radiologists, while 198 (50.64%) have the maximum volume overlapping ratios <60%. The results also showed that 72.89% of the nodules were assessed with malignancy score between 2 and 4, and only 7.93% of these nodules were considered as severely malignant (malignancy {>=}4). Conclusions: This study demonstrates that LIDC contains examinations covering a diverse distribution of nodule characteristics and it can be a useful resource to assess the performance of the nodule detection and/or segmentation schemes.

  7. Computerization of Hungarian reforestation manual with machine learning methods

    Science.gov (United States)

    Czimber, Kornél; Gálos, Borbála; Mátyás, Csaba; Bidló, András; Gribovszki, Zoltán

    2017-04-01

    Hungarian forests are highly sensitive to the changing climate, especially to the available precipitation amount. Over the past two decades several drought damages were observed for tree species which are in the lower xeric limit of their distribution. From year to year these affected forest stands become more difficult to reforest with the same native species because these are not able to adapt to the increasing probability of droughts. The climate related parameter set of the Hungarian forest stand database needs updates. Air humidity that was formerly used to define the forest climate zones is not measured anymore and its value based on climate model outputs is highly uncertain. The aim was to develop a novel computerized and objective method to describe the species-specific climate conditions that is essential for survival, growth and optimal production of the forest ecosystems. The method is expected to project the species spatial distribution until 2100 on the basis of regional climate model simulations. Until now, Hungarian forest managers have been using a carefully edited spreadsheet for reforestation purposes. Applying binding regulations this spreadsheet prescribes the stand-forming and admixed tree species and their expected growth rate for each forest site types. We are going to present a new machine learning based method to replace the former spreadsheet. We took into great consideration of various methods, such as maximum likelihood, Bayesian networks, Fuzzy logic. The method calculates distributions, setups classification, which can be validated and modified by experts if necessary. Projected climate change conditions makes necessary to include into this system an additional climate zone that does not exist in our region now, as well as new options for potential tree species. In addition to or instead of the existing ones, the influence of further limiting parameters (climatic extremes, soil water retention) are also investigated. Results will be

  8. A computerized system to monitor resilience indicators in organizations.

    Science.gov (United States)

    de Carvalho, Paulo Victor Rodrigues; de Souza, Alan Pinheiro; Gomes, Jose Orlando

    2012-01-01

    The concepts developed by resilience engineering allow the understanding and monitoring the functioning of organizations and, particularly, to map the role of human activities, in success or in failure, enabling a better comprehension about how people make decisions in unexpected situations. The capture of information about human activities in the various organization levels gives managers a deeper real-time understanding of what is influencing the people performance, providing awareness of the factors that influence positively or negatively the organizational goals initially projected. The monitoring is important because the correct functioning of complex systems depends on the knowledge that people have to perform their activities and how the system environment provides tools that actually support the human performance. Therefore, organizations should look forward through precursors in operating signals to identify possible problems or solutions in the structure of tasks and activities, safety, quality, schedule, rework, and maintenance. We apply the concepts of resilience engineering to understand the organization by the analysis of cognitive tasks and activities. The aim is the development of a computerized system to monitor human activities to produce indicators to access system resilience. The validation of the approach was made in a real organization and the results show the successful applicability of the system. Based on findings obtained after the experiment of the system in a real organization, and managers and workers opinions, it was possible to show that the use of system provided an anticipated (real-time) perception about how activities are effectively being performed, allowing managers and workers to make decisions more consistent with daily problems, and also to anticipate solutions to cope with unexpected situations.

  9. Meaning of Interior Tomography

    CERN Document Server

    Wang, Ge

    2013-01-01

    The classic imaging geometry for computed tomography is for collection of un-truncated projections and reconstruction of a global image, with the Fourier transform as the theoretical foundation that is intrinsically non-local. Recently, interior tomography research has led to theoretically exact relationships between localities in the projection and image spaces and practically promising reconstruction algorithms. Initially, interior tomography was developed for x-ray computed tomography. Then, it has been elevated as a general imaging principle. Finally, a novel framework known as omni-tomography is being developed for grand fusion of multiple imaging modalities, allowing tomographic synchrony of diversified features.

  10. Pain Perception: Computerized versus Traditional Local Anesthesia in Pediatric Patients.

    Science.gov (United States)

    Mittal, M; Kumar, A; Srivastava, D; Sharma, P; Sharma, S

    2015-01-01

    Local anesthetic injection is one of the most anxiety- provoking procedure for both children and adult patients in dentistry. A computerized system for slow delivery of local anesthetic has been developed as a possible solution to reduce the pain related to the local anesthetic injection. The present study was conducted to evaluate and compare pain perception rates in pediatric patients with computerized system and traditional methods, both objectively and subjectively. It was a randomized controlled study in one hundred children aged 8-12 years in healthy physical and mental state, assessed as being cooperative, requiring extraction of maxillary primary molars. Children were divided into two groups by random sampling - Group A received buccal and palatal infiltration injection using Wand, while Group B received buccal and palatal infiltration using traditional syringe. Visual Analog scale (VAS) was used for subjective evaluation of pain perception by patient. Sound, Eye, Motor (SEM) scale was used as an objective method where sound, eye and motor reactions of patient were observed and heart rate measurement using pulse oximeter was used as the physiological parameter for objective evaluation. Patients experienced significantly less pain of injection with the computerized method during palatal infiltration, while less pain was not statistically significant during buccal infiltration. Heart rate increased during both buccal and palatal infiltration in traditional and computerized local anesthesia, but difference between traditional and computerized method was not statistically significant. It was concluded that pain perception was significantly more during traditional palatal infiltration injection as compared to computerized palatal infiltration, while there was no difference in pain perception during buccal infiltration in both the groups.

  11. Monte Carlo simulation of gamma ray tomography for image reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Guedes, Karlos A.N.; Moura, Alex; Dantas, Carlos; Melo, Silvio; Lima, Emerson, E-mail: karlosguedes@hotmail.com [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); Meric, Ilker [University of Bergen (Norway)

    2015-07-01

    The Monte Carlo simulations of known density and shape object was validate with Gamma Ray Tomography in static experiments. An aluminum half-moon piece placed inside a steel pipe was the MC simulation test object that was also measured by means of gamma ray transmission. Wall effect of the steel pipe due to irradiation geometry in a single pair source-detector tomography was evaluated by comparison with theoretical data. MCNPX code requires a defined geometry to each photon trajectory which practically prevents this usage for tomography reconstruction simulation. The solution was found by writing a program in Delphi language to create input files automation code. Simulations of tomography data by automated MNCPX code were carried out and validated by experimental data. Working in this sequence the produced data needed a databank to be stored. Experimental setup used a Cesium-137 isotopic radioactive source (7.4 × 109 Bq), and NaI(Tl) scintillation detector of (51 × 51) × 10−3 m crystal size coupled to a multichannel analyzer. A stainless steel tubes of 0,154 m internal diameter, 0.014 m thickness wall. The results show that the MCNPX simulation code adapted to automated input file is useful for generating a matrix data M(θ,t), of a computerized gamma ray tomography for any known density and regular shape object. Experimental validation used RMSE from gamma ray paths and from attenuation coefficient data. (author)

  12. The Use of Statistical Process Control-Charts for Person-Fit Analysis on Computerized Adaptive Testing. LSAC Research Report Series.

    Science.gov (United States)

    Meijer, Rob R.; van Krimpen-Stoop, Edith M. L. A.

    In this study a cumulative-sum (CUSUM) procedure from the theory of Statistical Process Control was modified and applied in the context of person-fit analysis in a computerized adaptive testing (CAT) environment. Six person-fit statistics were proposed using the CUSUM procedure, and three of them could be used to investigate the CAT in online test…

  13. Ultrasound transmission attenuation tomography using energy-scaled amplitude ratios

    Science.gov (United States)

    Chen, Ting; Shin, Junseob; Huang, Lianjie

    2016-04-01

    Ultrasound attenuation of breast tumors is related to their types and pathological states, and can be used to detect and characterize breast cancer. Particularly, ultrasound scattering attenuation can infer the margin properties of breast tumors. Ultrasound attenuation tomography quantitatively reconstructs the attenuation properties of the breast. Our synthetic-aperture breast ultrasound tomography system with two parallel transducer arrays records both ultrasound reflection and transmission signals. We develop an ultrasound attenuation tomography method using ultrasound energy-scaled amplitude decays of ultrasound transmission signals and conduct ultrasound attenuation tomography using a known sound-speed model. We apply our ultrasound transmission attenuation tomography method to a breast phantom dataset, and compare the ultrasound attenuation tomography results with conventional beamforming ultrasound images obtained using reflection signals. We show that ultrasound transmission attenuation tomography complements beamforming images in identifying breast lesions.

  14. Documentation of Nursing Practice Using a Computerized Medical Information System

    Science.gov (United States)

    Romano, Carol

    1981-01-01

    This paper discusses a definition of the content of the computerized nursing data base developed by the Nursing Department for the Clinical Center Medical Information System at the National Institutes of Health in Bethesda, Maryland. The author describes the theoretical framework for the content and presents a model to describe the organization of the nursing data components in relation to the process of nursing care delivery. Nursing documentation requirements of Nurse Practice Acts, American Nurses Association Standards of Practice and the Joint Commission on Accreditation of Hospitals are also addressed as they relate to this data base. The advantages and disadvantages of such an approach to computerized documentation are discussed.

  15. THE VALIDITY OF HUMAN AND COMPUTERIZED WRITING ASSESSMENT

    Energy Technology Data Exchange (ETDEWEB)

    Ronald L. Boring

    2005-09-01

    This paper summarizes an experiment designed to assess the validity of essay grading between holistic and analytic human graders and a computerized grader based on latent semantic analysis. The validity of the grade was gauged by the extent to which the student’s knowledge of the topic correlated with the grader’s expert knowledge. To assess knowledge, Pathfinder networks were generated by the student essay writers, the holistic and analytic graders, and the computerized grader. It was found that the computer generated grades more closely matched the definition of valid grading than did human generated grades.

  16. Construct Validation of a Multidimensional Computerized Adaptive Test for Fatigue in Rheumatoid Arthritis

    NARCIS (Netherlands)

    Nikolaus, Stephanie; Bode, Christina; Taal, Erik; Vonkeman, Harald E.; Glas, Cees A.W.; Laar, van de Mart A.F.J.

    2015-01-01

    Objective Multidimensional computerized adaptive testing enables precise measurements of patient-reported outcomes at an individual level across different dimensions. This study examined the construct validity of a multidimensional computerized adaptive test (CAT) for fatigue in rheumatoid arthritis

  17. X-ray multi-modal tomography using the speckle vector tracking technique

    CERN Document Server

    Berujon, Sebastien

    2015-01-01

    We demonstrate computerized tomography (CT) reconstruction from absorption, phase and dark-field signals obtained from scans where the X-ray probe light is modulated with speckle. Two different interlaced schemes are proposed to reduce the number of sample exposures as well as the total time of irradiation. The first scheme allows tomographic reconstruction with the three different signals obtained from multiple images per projection whilst the second one provides absorption and phase reconstruction but from a single image per angular projection. Experimental reconstructions of tomography data obtained at a synchrotron facility emphasize the potential of the approach for the imaging of dose sensitive samples.

  18. Bronchiolitis obliterans following exposure to sulfur mustard: chest high resolution computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ghanei, Mostafa E-mail: m.ghanei@bmsu.ac.ir; Mokhtari, Majid; Mohammad, Mehdi Mir; Aslani, Jafar

    2004-11-01

    Background: Pulmonary complications are known to occur in over half of the patients exposed to sulfur mustard (SM). Chemical weapons of mass destruction (WMD) including SM were used by Iraq during Iran-Iraq war between 1983 and 1989. We undertook this study to evaluate the chest high resolution computerized tomography (HRCT) as a diagnostic tool in patients with documented exposure to SM and chronic respiratory symptoms. Method: The medical records of 155 patients exposed to SM during Iran-Iraq war and suffered respiratory complications were reviewed. Chest HRCTs of these patients were examined. Ten healthy controls with no history of exposure to HD were matched for age, gender, and chest HRCT protocol applied. Results: Fifty chest HRCTs of these patients were randomly selected for this study. The most frequent findings were; air trapping 38 (76%), bronchiectasis 37 (74%), mosaic parenchymal attenuation (MPA) 36 (72%), irregular and dilated major airways 33 (66%) bronchial wall thickening (BWT) 45 (90%), and interlobular septal wall thickening (SWT) 13 (26%), respectively. Air trapping in one patient (10%) was the only positive finding in the control group. Conclusions: Chest HRCT findings of bronchiectasis, air trapping, MPA, SWT, and BWT were seen in our patients 15 years after exposure to HD. These findings suggest the diagnosis of bronchiolitis obliterans (BO). We did not encounter chest HRCT features consistent with pulmonary fibrosis.

  19. Turbocharging Quantum Tomography.

    Energy Technology Data Exchange (ETDEWEB)

    Blume-Kohout, Robin J; Gamble, John King,; Nielsen, Erik; Maunz, Peter Lukas Wilhelm; Scholten, Travis L.; Rudinger, Kenneth Michael

    2015-01-01

    Quantum tomography is used to characterize quantum operations implemented in quantum information processing (QIP) hardware. Traditionally, state tomography has been used to characterize the quantum state prepared in an initialization procedure, while quantum process tomography is used to characterize dynamical operations on a QIP system. As such, tomography is critical to the development of QIP hardware (since it is necessary both for debugging and validating as-built devices, and its results are used to influence the next generation of devices). But tomography su %7C ers from several critical drawbacks. In this report, we present new research that resolves several of these flaws. We describe a new form of tomography called gate set tomography (GST), which unifies state and process tomography, avoids prior methods critical reliance on precalibrated operations that are not generally available, and can achieve unprecedented accuracies. We report on theory and experimental development of adaptive tomography protocols that achieve far higher fidelity in state reconstruction than non-adaptive methods. Finally, we present a new theoretical and experimental analysis of process tomography on multispin systems, and demonstrate how to more e %7C ectively detect and characterize quantum noise using carefully tailored ensembles of input states.

  20. Turbocharging Quantum Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Blume-Kohout, Robin J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Gamble, John King [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Nielsen, Erik [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Maunz, Peter Lukas Wilhelm [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Scholten, Travis L. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Rudinger, Kenneth Michael [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-01-01

    Quantum tomography is used to characterize quantum operations implemented in quantum information processing (QIP) hardware. Traditionally, state tomography has been used to characterize the quantum state prepared in an initialization procedure, while quantum process tomography is used to characterize dynamical operations on a QIP system. As such, tomography is critical to the development of QIP hardware (since it is necessary both for debugging and validating as-built devices, and its results are used to influence the next generation of devices). But tomography suffers from several critical drawbacks. In this report, we present new research that resolves several of these flaws. We describe a new form of tomography called gate set tomography (GST), which unifies state and process tomography, avoids prior methods critical reliance on precalibrated operations that are not generally available, and can achieve unprecedented accuracies. We report on theory and experimental development of adaptive tomography protocols that achieve far higher fidelity in state reconstruction than non-adaptive methods. Finally, we present a new theoretical and experimental analysis of process tomography on multispin systems, and demonstrate how to more effectively detect and characterize quantum noise using carefully tailored ensembles of input states.

  1. Diffraction and coherence in breast ultrasound tomography: a study with a toroidal array

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Lianjie [Los Alamos National Laboratory; Simonetti, Francesco [IMPERIAL COLL.; Duric, Neb [KCI; Littrup, Peter [KCI

    2008-01-01

    Ultrasound is commonly used as an adjunct to mammography for diagnostic evaluation of suspicions arising from breast cancer screening. As an alternative to conventional sonography that uses hand-held transducers, toroidal array probes that encircle the breast immersed in a water bath have been investigated for ultrasound tomography. In this paper, two sets of experiments performed with a prototype ultrasound scanner on a phantom and a human breast in vivo are used to investigate the effects of diffraction and coherence in ultrasound tomography. Reconstructions obtained with transmission diffraction tomography (TDT) are compared with conventional reflection imaging and computerized ultrasound tomography showing a substantial improvement. The in vivo tests demonstrate that TDT can image the complex boundary of a cancer mass and suggest that it can reveal the anatomy of milk ducts and Cooper's ligaments.

  2. Computer tomography as a means of detecting perirenal bleeding after renal biopsy

    Energy Technology Data Exchange (ETDEWEB)

    Monhart, V.; Sobota, J.; Navratil, J. (Ustredni Vojenska Nemocnice, Prague (Czechoslovakia)); Jaros, M.; Stepankova, C. (Karlova Univ., Prague (Czechoslovakia). Lekarska Fakulta Hygienicka)

    1983-02-18

    Perirenal bleeding was detected in 23 cases, i.e., 85%, of a group of 27 patients examined using computerized tomography, after percutaneous renal biopsy. The computerized tomography tests were made with a Siemens Somatom 2 apparatus at the 2nd and 3rd post-biopsy days except for 1 patient who was not examined until the 8th day. Apart from localization, the size and spread of perirenal bleeding was sought. The predominant finding was a small perirenal hematoma. The simultaneous presence of minute intrarenal hematoma was ascertained in only 3 patients. Asymptomatic course was seen in 30% of the X-ray-proved cases of hemorrhage. The authors were unable to prove any relationship between the size, type and spread of perirenal bleeding and the presence of clinical signs or the number of renal biopsy punctures. Thanks to its non-invasive nature and high sensitivity, computerized tomography is rated as a reliable method for the early detection, and determination of the size, precise localization, age and absorption of hematomas resulting from percutaneous renal biopsy.

  3. Near-Infrared Diffuse Optical Tomography

    Directory of Open Access Journals (Sweden)

    A. H. Hielscher

    2002-01-01

    Full Text Available Diffuse optical tomography (DOT is emerging as a viable new biomedical imaging modality. Using near-infrared (NIR light, this technique probes absorption as well as scattering properties of biological tissues. First commercial instruments are now available that allow users to obtain cross-sectional and volumetric views of various body parts. Currently, the main applications are brain, breast, limb, joint, and fluorescence/bioluminescence imaging. Although the spatial resolution is limited when compared with other imaging modalities, such as magnetic resonance imaging (MRI or X-ray computerized tomography (CT, DOT provides access to a variety of physiological parameters that otherwise are not accessible, including sub-second imaging of hemodynamics and other fast-changing processes. Furthermore, DOT can be realized in compact, portable instrumentation that allows for bedside monitoring at relatively low cost. In this paper, we present an overview of current state-of-the -art technology, including hardware and image-reconstruction algorithms, and focus on applications in brain and joint imaging. In addition, we present recent results of work on optical tomographic imaging in small animals.

  4. Camera calibration for multidirectional flame chemiluminescence tomography

    Science.gov (United States)

    Wang, Jia; Zhang, Weiguang; Zhang, Yuhong; Yu, Xun

    2017-04-01

    Flame chemiluminescence tomography (FCT), which combines computerized tomography theory and multidirectional chemiluminescence emission measurements, can realize instantaneous three-dimensional (3-D) diagnostics for flames with high spatial and temporal resolutions. One critical step of FCT is to record the projections by multiple cameras from different view angles. For high accuracy reconstructions, it requires that extrinsic parameters (the positions and orientations) and intrinsic parameters (especially the image distances) of cameras be accurately calibrated first. Taking the focus effect of the camera into account, a modified camera calibration method was presented for FCT, and a 3-D calibration pattern was designed to solve the parameters. The precision of the method was evaluated by reprojections of feature points to cameras with the calibration results. The maximum root mean square error of the feature points' position is 1.42 pixels and 0.0064 mm for the image distance. An FCT system with 12 cameras was calibrated by the proposed method and the 3-D CH* intensity of a propane flame was measured. The results showed that the FCT system provides reasonable reconstruction accuracy using the camera's calibration results.

  5. Computerized Classification Testing under the Generalized Graded Unfolding Model

    Science.gov (United States)

    Wang, Wen-Chung; Liu, Chen-Wei

    2011-01-01

    The generalized graded unfolding model (GGUM) has been recently developed to describe item responses to Likert items (agree-disagree) in attitude measurement. In this study, the authors (a) developed two item selection methods in computerized classification testing under the GGUM, the current estimate/ability confidence interval method and the cut…

  6. Computerized Adaptive Testing, Anxiety Levels, and Gender Differences

    Science.gov (United States)

    Fritts, Barbara E.; Marszalek, Jacob M.

    2010-01-01

    This study compares the amount of test anxiety experienced on a computerized adaptive test (CAT) to a paper-and-pencil test (P&P), as well as the state test anxiety experienced between males and females. Ninety-four middle school CAT examinees were compared to 65 middle school P&P examinees on their responses to the State-Trait Anxiety Inventory…

  7. Validation of Computerized Cognitive Assessment in Cross-Cultural Populations

    Science.gov (United States)

    2013-04-01

    B, WAIS-R Coding) in predominantly Caucasian samples (e.g. Kabat et al., 2001). 8 TABLE 5: Pearson Product Moment Correlations...satisfaction with computerized versus traditional cognitive testing. References Kabat , M.H., Kane, R.L., Jefferson, A.L., & DiPino, R.K. (2001

  8. Modern Sequential Analysis and Its Applications to Computerized Adaptive Testing

    Science.gov (United States)

    Bartroff, Jay; Finkelman, Matthew; Lai, Tze Leung

    2008-01-01

    After a brief review of recent advances in sequential analysis involving sequential generalized likelihood ratio tests, we discuss their use in psychometric testing and extend the asymptotic optimality theory of these sequential tests to the case of sequentially generated experiments, of particular interest in computerized adaptive testing. We…

  9. A more cost-effective method of preoperative computerized imaging.

    Science.gov (United States)

    Webber, W B

    1989-07-01

    Stimulated by the explosive expansion of the computerized desk top publishing industry during the past few years, microcomputer hardware and software are evolving at a staggering rate. Memory is rapidly increasing, and prices are declining. I have found that with the hardware and software described in this paper, I was able to obtain, in a much more cost-effective manner, as useful preoperative information for my practice as I could obtain with more expensive "turnkey" (only one use) computerized imaging systems. This type of microcomputer, of course, is not limited to just the imaging system, but can be used for a variety of other programs as well, such as word processing, slide labeling and production, spreadsheet functions, billing and filing, and numerous business and other applications. The ease of use with readily available 35-mm slides of my patients has greatly enhanced the appeal of this system. Computerized imaging, when used as an educational tool, can be very helpful in preoperative planning, resident teaching, and for illustration and discussion of a patient's proposed surgery. The electronic imaging disclaimer compiled by the American Society of Plastic and Reconstructive Surgeons has been extremely helpful in clarifying the limits of computerized imaging and reducing any false expectations that my patients might have. All of us are experiencing the dawn of a very exciting evolution.

  10. Computerized Atlases: The Potential of Computers in Social Studies.

    Science.gov (United States)

    de Leeuw, G.; Waters, N. M.

    1986-01-01

    Examines the use of computer atlases to see how they might contribute to the attainment of established social studies goals. Reviews advantages and disadvantages of existing software and hardware. Describes the potentials of computerized atlases and the hardware required to support such uses. (JDH)

  11. Multistage Computerized Adaptive Testing with Uniform Item Exposure

    Science.gov (United States)

    Edwards, Michael C.; Flora, David B.; Thissen, David

    2012-01-01

    This article describes a computerized adaptive test (CAT) based on the uniform item exposure multi-form structure (uMFS). The uMFS is a specialization of the multi-form structure (MFS) idea described by Armstrong, Jones, Berliner, and Pashley (1998). In an MFS CAT, the examinee first responds to a small fixed block of items. The items comprising…

  12. Limb-length discrepancy measured with computerized axial tomographic equipment

    Energy Technology Data Exchange (ETDEWEB)

    Huurman, W.W.; Jacobsen, F.S.; Anderson, J.C.; Chu, W.K.

    1987-06-01

    A simple, rapid, and accurate method for measuring limb-length discrepancies with computerized axial tomographic equipment is described. With this method less irradiation is delivered and some of the errors of computation are eliminated, compared with conventional methods. The costs of the technique are comparable with those of scanograms. The method is particularly applicable in the patient who has contracture of a joint.

  13. Computerized sociometric and peer assessment: An empirical and practical evaluation

    NARCIS (Netherlands)

    Berg, Y.H.M. van den; Cillessen, A.H.N.

    2013-01-01

    A systematic analysis and comparison was conducted of the psychometric properties of standard (paper-and-pencil) and computerized sociometry and peer assessments. The standard assessment took place with 817 children (47.5% boys) in 34 fifth- and sixth-grade classrooms of 28 elementary schools. The c

  14. NCLEX-RN Performance: Predicting Success on the Computerized Examination.

    Science.gov (United States)

    Waterhouse, Julie Keith; Beeman, Pamela Butler

    2001-01-01

    Discriminant analysis was used to identify variables predictive of success in the computerized National Council Licensure Examination for Registered Nurses with data from 289 nursing graduates. Using seven significant predictors, 94% of passes and 92% of failures were correctly identified. (Contains 23 references.) (SK)

  15. Computerized comprehensive data analysis of Lung Imaging Database Consortium (LIDC)

    OpenAIRE

    Tan, Jun; Pu, Jiantao; Zheng, Bin; Wang, Xingwei; Leader, Joseph K.

    2010-01-01

    Purpose: Lung Image Database Consortium (LIDC) is the largest public CT image database of lung nodules. In this study, the authors present a comprehensive and the most updated analysis of this dynamically growing database under the help of a computerized tool, aiming to assist researchers to optimally use this database for lung cancer related investigations.

  16. Computerized Atlases: The Potential of Computers in Social Studies.

    Science.gov (United States)

    de Leeuw, G.; Waters, N. M.

    1986-01-01

    Examines the use of computer atlases to see how they might contribute to the attainment of established social studies goals. Reviews advantages and disadvantages of existing software and hardware. Describes the potentials of computerized atlases and the hardware required to support such uses. (JDH)

  17. Multidimensional Computerized Adaptive Testing for Indonesia Junior High School Biology

    Science.gov (United States)

    Kuo, Bor-Chen; Daud, Muslem; Yang, Chih-Wei

    2015-01-01

    This paper describes a curriculum-based multidimensional computerized adaptive test that was developed for Indonesia junior high school Biology. In adherence to the Indonesian curriculum of different Biology dimensions, 300 items was constructed, and then tested to 2238 students. A multidimensional random coefficients multinomial logit model was…

  18. Duplicated laboratory tests: evaluation of a computerized alert intervention abstract.

    Science.gov (United States)

    Bridges, Sharon A; Papa, Linda; Norris, Anne E; Chase, Susan K

    2014-01-01

    Redundant testing contributes to reductions in healthcare system efficiency. The purpose of this study was to: (1) determine if the use of a computerized alert would reduce the number and cost of duplicated Acute Hepatitis Profile (AHP) laboratory tests and (2) assess what patient, test, and system factors were associated with duplication. This study used a quasi-experimental pre- and post-test design to determine the proportion of duplication of the AHP test before and after implementation of a computerized alert intervention. The AHP test was duplicated if the test was requested again within 15 days of the initial test being performed and the result present in the medical record. The intervention consisted of a computerized alert (pop-up window) that indicated to the clinician that the test had recently been ordered. A total of 674 AHP tests were performed in the pre-intervention period and 692 in the postintervention group. In the pre-intervention period, 53 (7.9%) were duplicated and in postintervention, 18 (2.6%) were duplicated (ptests (p≤.001). Implementation of computerized alerts may be useful in reducing duplicate laboratory tests and improving healthcare system efficiency.

  19. Discovering Visual Scanning Patterns in a Computerized Cancellation Test

    Science.gov (United States)

    Huang, Ho-Chuan; Wang, Tsui-Ying

    2013-01-01

    The purpose of this study was to develop an attention sequential mining mechanism for investigating the sequential patterns of children's visual scanning process in a computerized cancellation test. Participants had to locate and cancel the target amongst other non-targets in a structured form, and a random form with Chinese stimuli. Twenty-three…

  20. Computerized Screening for Visual Stress in Children with Dyslexia

    Science.gov (United States)

    Singleton, Chris; Henderson, Lisa-Marie

    2007-01-01

    Visual stress--a condition in which unpleasant visual symptoms are experienced when reading--has been reported to be more prevalent in dyslexic individuals but at the present time the relationship between dyslexia and visual stress remains controversial. ViSS, a computerized visual stress screener that incorporates reading-like visual search, has…

  1. 381 Developing of a Computerized Brain Diagnosing System for ...

    African Journals Online (AJOL)

    User

    (Pp. 381-396). Ogunsanwo O. D. - Department of Computer Science, Gate way ICT ... computerized brain diagnosing system that would be used in carrying out the .... on Artificial Intelligence (AI) technology are being built into photocopiers, ..... This aspect explores the techniques use for the design of interface, menus and.

  2. The Effects of Computerized Information Systems on Juvenile Courts

    Science.gov (United States)

    Albrecht, Gary L.

    1976-01-01

    Organizational theorists alternatively hypothesized that computerized information systems (CIS) will produce no necessary changes, centralization, or decentralization in juvenile courts. This hypothesis is supported by the results of a four year study on the phenomenon. Suggestions are offered for improving the juvenile judicial system through…

  3. Computerized adaptive testing for measuring development of young children

    NARCIS (Netherlands)

    Jacobusse, G.; Buuren, S. van

    2007-01-01

    Developmental indicators that are used for routine measurement in The Netherlands are usually chosen to optimally identify delayed children. Measurements on the majority of children without problems are therefore quite imprecise. This study explores the use of computerized adaptive testing (CAT) to

  4. Multidimensional Computerized Adaptive Testing for Indonesia Junior High School Biology

    Science.gov (United States)

    Kuo, Bor-Chen; Daud, Muslem; Yang, Chih-Wei

    2015-01-01

    This paper describes a curriculum-based multidimensional computerized adaptive test that was developed for Indonesia junior high school Biology. In adherence to the Indonesian curriculum of different Biology dimensions, 300 items was constructed, and then tested to 2238 students. A multidimensional random coefficients multinomial logit model was…

  5. Computerized Mastery Testing Using Fuzzy Set Decision Theory.

    Science.gov (United States)

    Du, Yi; And Others

    1993-01-01

    A new computerized mastery test is described that builds on the Lewis and Sheehan procedure (sequential testlets) (1990), but uses fuzzy set decision theory to determine stopping rules and the Rasch model to calibrate items and estimate abilities. Differences between fuzzy set and Bayesian methods are illustrated through an example. (SLD)

  6. Monkeys Exhibit Prospective Memory in a Computerized Task

    Science.gov (United States)

    Evans, Theodore A.; Beran, Michael J.

    2012-01-01

    Prospective memory (PM) involves forming intentions, retaining those intentions, and later executing those intended responses at the appropriate time. Few studies have investigated this capacity in animals. Monkeys performed a computerized task that assessed their ability to remember to make a particular response if they observed a PM cue embedded…

  7. The Nominal Response Model in Computerized Adaptive Testing.

    Science.gov (United States)

    De Ayala, R. J.

    One important and promising application of item response theory (IRT) is computerized adaptive testing (CAT). The implementation of a nominal response model-based CAT (NRCAT) was studied. Item pool characteristics for the NRCAT as well as the comparative performance of the NRCAT and a CAT based on the three-parameter logistic (3PL) model were…

  8. An Assessment of a Computerized Simulation of Counseling Skills.

    Science.gov (United States)

    Sharf, Richard S.; Lucas, Margaretha

    1993-01-01

    Developed Computerized Counseling Simulation, simulation of client-counselor interaction. Tested simulation on seven groups with varying degrees of counseling experience: counselors, predoctoral counseling interns, counseling students, first-year counseling students, student peer counselors, undergraduates, and noncounselors (total n=108). Interns…

  9. 11 CFR 9033.12 - Production of computerized information.

    Science.gov (United States)

    2010-01-01

    ... and assistance. Upon request, the committee shall provide documentation explaining the computer system... make available such personnel as are necessary to explain the operation of the computer system's... 11 Federal Elections 1 2010-01-01 2010-01-01 false Production of computerized information....

  10. Rice seed identification by computerized AFLP-DNA fingerprinting

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@ We developed a computerized seed identification system. Fifteen rice varieties that were widely used in China were analyzed by AFLP fingerprinting. 12 primer pairs were screened. In order to simplify the procedure and cut down the cost in seed identification, the least number of primer pairs for practical seed identification should be selected. In this study, 3 primer pairs were selected.

  11. Computerized adaptive testing in industrial and organizational psychology

    NARCIS (Netherlands)

    Makransky, Guido

    2012-01-01

    The overarching goal of this dissertation is to increase the precision and efficiency of the measurement tools that are used to make selection decisions in industrial/organizational psychology, by introducing psychometric innovations in the framework of computerized adaptive testing (CAT). Chapter 1

  12. Study of dosimetric quantities applied to patient undergoing routine chest examinations by computed tomography; Estudo de grandezas dosimetricas aplicadas em pacientes submetidos a exames de torax rotina em tomografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Gonzaga, Natalia Barbosa

    2012-07-01

    The radiological protection system has established a standard to protect persons against the harmful effects caused by ionizing radiation that is based on the justification, optimization and dose limitation principles. The increasing use of radiation in medicine and the related risks have stressed the discussion on patient radiation protection. The computed tomography (CT) is the diagnostic radiology technique that most contributes to patient doses and it requires optimization efforts. Diagnostic reference levels (DRL) has been established in many countries in terms of CT dosimetric quantities; in Brazil, the DRLs are still under investigation since the culture of patient protection is not very strong yet. The objective of this work was to investigate the dosimetric and protection quantities related to patients undergoing CT routine chest examinations. The ImPACT CT, CT Expo and ImpactDose softwares were used for calculations of the weight and volumetric air-kerma indexes (CW and CVOL), the air kerma - length product (P{sub K,L}), organ equivalent dose (H{sub T}) and the effective dose (E) for CT routine chest protocols in 19 tomographs in Belo Horizonte city. The CT Expo was selected to be validated against experimental measurements in three hospitals with thermoluminescent dosimeters and CT pencil ionization chamber in anthropomorphic and standard CT body phantoms. Experimental and calculated results indicated differences up to 97% for H{sub T} and E and acceptable agreement for C{sub W} ,C{sub VOL} and P{sub K,L}. All data from 19 tomographs showed that local DRLs for CT routine chest examinations may be chosen smaller than DRLs adopted in other countries; this would contribute to increase the radiological protection of patients. (author)

  13. A combination of physical activity and computerized brain training improves verbal memory and increases cerebral glucose metabolism in the elderly

    Science.gov (United States)

    Shah, T; Verdile, G; Sohrabi, H; Campbell, A; Putland, E; Cheetham, C; Dhaliwal, S; Weinborn, M; Maruff, P; Darby, D; Martins, R N

    2014-01-01

    Physical exercise interventions and cognitive training programs have individually been reported to improve cognition in the healthy elderly population; however, the clinical significance of using a combined approach is currently lacking. This study evaluated whether physical activity (PA), computerized cognitive training and/or a combination of both could improve cognition. In this nonrandomized study, 224 healthy community-dwelling older adults (60–85 years) were assigned to 16 weeks home-based PA (n=64), computerized cognitive stimulation (n=62), a combination of both (combined, n=51) or a control group (n=47). Cognition was assessed using the Rey Auditory Verbal Learning Test, Controlled Oral Word Association Test and the CogState computerized battery at baseline, 8 and 16 weeks post intervention. Physical fitness assessments were performed at all time points. A subset (total n=45) of participants underwent [18F] fluorodeoxyglucose positron emission tomography scans at 16 weeks (post-intervention). One hundred and ninety-one participants completed the study and the data of 172 participants were included in the final analysis. Compared with the control group, the combined group showed improved verbal episodic memory and significantly higher brain glucose metabolism in the left sensorimotor cortex after controlling for age, sex, premorbid IQ, apolipoprotein E (APOE) status and history of head injury. The higher cerebral glucose metabolism in this brain region was positively associated with improved verbal memory seen in the combined group only. Our study provides evidence that a specific combination of physical and mental exercises for 16 weeks can improve cognition and increase cerebral glucose metabolism in cognitively intact healthy older adults. PMID:25463973

  14. Reconstruction of an InAs nanowire using geometric tomography

    DEFF Research Database (Denmark)

    Pennington, Robert S.; König, Stefan; Alpers, Andreas;

    Geometric tomography and conventional algebraic tomography algorithms are used to reconstruct cross-sections of an InAs nanowire from a tilt series of experimental annular dark-field images. Both algorithms are also applied to a test object to assess what factors affect the reconstruction quality...

  15. Neutron stimulated emission computed tomography applied to the assessment of calcium deposition due to the presence of microcalcifications associated with breast cancer; Tomografia computadorizada de emissao estimulada por neutrons aplicada para avaliar a deposicao de calcio devido a presenca de microcalcificacoes associadas ao cancer de mama

    Energy Technology Data Exchange (ETDEWEB)

    Viana, Rodrigo S.S.; Yoriyaz, Helio [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, (SP) (Brazil)

    2011-07-01

    In this paper we presented an application of the Neutron Stimulated Emission Computed Tomography (NSECT), which uses a thin beam of fast neutrons to stimulate stable nuclei in a sample, emitting characteristic gamma radiation. The photon energy is unique and it is used to identify the emitting nuclei. This technique was applied for evaluating the calcium isotopic composition changing due to the development of breast microcalcifications. A particular situation was simulated in which clustered microcalcifications were modeled with diameters less than 1.40 mm. In this case, neutron beam breast spectroscopy was successful in detecting the counting changes in the photon emission spectra for energies, which are characteristics of 4{sup 0C}a isotope in a low deposited dose rate. (author)

  16. Computerized mathematics games as teaching aid

    OpenAIRE

    Salami, Azeez Deji; Somova, Olga

    2013-01-01

    Some game enthusiastic writers claim that educational games have huge potentials in children education (Keith Devlin, 2011 & Fengfeng Ke, 2008). Many scholars are though skeptical about this claim. In this report, the use of educational games as a teaching tool was studied. The pedagogic theories and approaches applied in designs of some recent educational games were investigated. Mathematics teaching in Danish schools was also. Based on two of the approaches used in some educational game des...

  17. Computerized neurocognitive interventions in the context of the brain training controversy.

    Science.gov (United States)

    García-Betances, Rebeca Isabel; Cabrera-Umpiérrez, María Fernanda; Arredondo, María T

    2017-08-19

    This article presents, in the form of an analytic narrative review, a complete picture of the state-of-the-art, challenges, and perspectives in the field of information and communication technology (ICT)-based neurocognitive interventions for older adults. The narrative particularly focuses on applications aimed at mild cognitive impairment and similar age-related cognitive deficits, which are analyzed in the context of the brain training controversy. Clarifying considerations are provided about the nature and present extent of the brain training debate, regarding the possible influence it has on the support received by research and development initiatives dealing with innovative computerized neurocognitive interventions. It is recommended that, because of the preliminary nature of most data currently available in this area, further research initiatives must be supported in the quest for better effectiveness of computer-based interventions intended for age-related cognitive impairment. The conclusion suggests that advanced ICT-based tools, such as virtual and augmented reality technologies, are the most fitting platforms for applying nonpharmacological computerized neurocognitive interventions.

  18. Exploration of computerized image processing in underexposed and overexposed X-rays of bones and joints

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhao-chen; ZHANG You-jun; FENG Cheng-qiang; ZHU Yuan-zhong; YAN Shi-yi; LIU Yu-jin

    2004-01-01

    Objective: To study the effective computerized image processing of underexposed and overexposed X-rays of bones and joints. Methods: Ninety-nine conventional X-ray images (82 were overexposed and 17 were underexposed),scanned by an UMAX Astra 4000U Scanner, were converted into digital images on the basis of their analog images. A computerized imaging processing program consisting of five functional modules such as Contrast Stretch, Fast Flourier Transform (FFT), Image Smoothing Modules, Inverse Fast Flourier Transform (IFFT) and Nonlinear Transform performed image contrast stretch and smoothing. Three senior doctors from hospital image sections made their evaluation of all the processed images. Results: Of 82 overexposed films, 71 met the clinical requirements after image processing, and 11 were unable to be applied to clinical diagnosis, accounting for 87% and 13% respectively. Of the other 17 underexposed X-ray images, 11 met the clinical requirements while 6 were not, making a percentage of 64 and 35. Conclusion: Image contrast stretch and smoothing processing are significantly effective on conventional X-ray images which were inappropriately exposed, and can avoid more X-ray radiation caused by handling of radiological photograph again. This method can decrease hospital cost and provide acute and effective X-ray examinations for the treatment and cure for critical patients.

  19. Computerized working memory training has positive long-term effect in very low birthweight preschool children.

    Science.gov (United States)

    Grunewaldt, Kristine Hermansen; Skranes, Jon; Brubakk, Ann-Mari; Lähaugen, Gro C C

    2016-02-01

    Working memory deficits are frequently found in children born preterm and have been linked to learning disabilities, and cognitive and behavioural problems. Our aim was to evaluate if a computerized working memory training program has long-term positive effects on memory, learning, and behaviour in very-low-birthweight (VLBW) children at age 5 to 6 years. This prospective, intervention study included 20 VLBW preschool children in the intervention group and 17 age-matched, non-training VLBW children in the comparison group. The intervention group trained with the Cogmed JM working memory training program daily for 5 weeks (25 training sessions). Extensive neuropsychological assessment and parental questionnaires were performed 4 weeks after intervention and at follow-up 7 months later. For most of the statistical analyses, general linear models were applied. At follow-up, higher scores and increased or equal performance gain were found in the intervention group than the comparison group on memory for faces (p=0.012), narrative memory (p=0.002), and spatial span (p=0.003). No group differences in performance gain were found for attention and behaviour. Computerized working memory training seems to have positive and persisting effects on working memory, and visual and verbal learning, at 7-month follow-up in VLBW preschool children. We speculate that such training is beneficial by improving the ability to learn from the teaching at school and for further cognitive development. © 2015 Mac Keith Press.

  20. Exploring transcendence in EFL learners’ reading comprehension through computerized dynamic assessment

    Directory of Open Access Journals (Sweden)

    Saman Ebadi

    2016-01-01

    Full Text Available Derived from Vygotsky’s works, dynamic assessment (DA enables learners to move beyond their current level of functioning through offering needs-sensitized mediation. This study aimed at exploring the learners’ development in novel and increasingly more challenging situations called transcendence (TR in an L2 context focusing on reading comprehension through computerized dynamic assessment (CDA. An overall number of 32 BA TEFL advanced students were selected from among undergraduates of a university in Iran to participate in this study. To fulfil the purpose of the study, the researchers developed Computerized Dynamic Reading Assessment to examine Transcendence (CDRAT software which included reading comprehension CDA tests. To monitor the maintenance of learning in different time intervals, two software programs named CDRAT1 and CDRAT2 were utilized in specific time intervals after the posttest. The results indicated that not only did increased task complexity not lead to regression of students’ development, but also it had an effect on enhancing their development. Thus, transcendence had an effect on the generalizability of the contentions to a great extent. In conclusion, it was disclosed that there is no endpoint to progress and merely gaining a low or high score should not be interpreted as the inability of a special learner to surpass. This would more reinforce the need for applying TR in other future DA studies.

  1. Criteria for anatomical compatibility of the total artificial heart: computerized three-dimensional modeling of the cardiovascular anatomy.

    Science.gov (United States)

    Chatel, D; Martin-Bouyer, Y; Vicaut, E; Bouchoucha, H; Achard, F; Sablayrolles, J L; Carpentier, A

    1993-12-01

    A quantitative study of cardiovascular anatomy was performed by obtaining three-dimensional reconstructions from regular computed tomography scan images in 15 patients, all candidates for heart transplantation. Volumetric estimates of the cardiovascular structures were obtained from these three-dimensional reconstructions using data directly related to total artificial heart (TAH) implantations. By using computerized three-dimensional modeling of these structures, reproducible measurements of the parameters defining the shape and the anatomical connections of the intrathoracic space available for TAH implantation could be derived. The results are intended to be used for both technical and clinical applications such as computer-assisted drawing of the pericardial cavity and the anatomical connections (useful for improving the design of TAH) and combined statistical calculations (multiple regressions, cluster algorithm) of the measurement results, which will then enable the best selection to be made among two or three TAH models for each patient.

  2. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Children's (Pediatric) CT (Computed Tomography) Pediatric computed tomography (CT) ... are the limitations of Children's CT? What is Children's CT? Computed tomography, more commonly known as a ...

  3. Tomography of nonclassical states

    NARCIS (Netherlands)

    Bazrafkan, MR; Man'ko, [No Value

    2003-01-01

    A review of the symplectic tomography method is presented. Superpositions of different types of photon states are considered within the framework of the tomography approach. Such nonclassical photon states as even and odd coherent states, crystallized Schrodinger cat states, and other superposition

  4. Tomography of nonclassical states

    NARCIS (Netherlands)

    Bazrafkan, MR; Man'ko, [No Value

    2003-01-01

    A review of the symplectic tomography method is presented. Superpositions of different types of photon states are considered within the framework of the tomography approach. Such nonclassical photon states as even and odd coherent states, crystallized Schrodinger cat states, and other superposition

  5. Early detection of response to imatinib therapy for gastrointestinal stromal tumor by using 18F-FDG-positron emission tomography and computed tomography imaging

    Institute of Scientific and Technical Information of China (English)

    Sabri Zincirkeser; Alper Sevinc; M Emin Kalender; Celalettin Camci

    2007-01-01

    A 41-year old female with metastatic gastrointestinal stromal tumor was referred to 18F-FDG-positron emission tomography and computed tomography (PET/CT) scan before and after one-month treatment with imatinib(Glivec(R), Gleevec(R), Novartis, Basel, Switzerland), a tyrosine kinase inhibitor (400 mg/d). Metabolic response was evaluated before and after one month of therapy. The decrease of the maximum standardised uptake value (SUV)was 79% (from 9.8 to 2.1). Positron emission tomography demonstrated complete metabolic response after one-month of imatinib treatment. Additionally, the previous lesion was compared with the coronal computerized tomographic image. There was no difference in the size of the tumor before and after therapy according to CT images. However, metabolic activity was inhibited.18F-FDG-PET is a valuable method for the detection of response to one-month imatinib treatment in patients with gastrointestinal stromal tumors.

  6. Decision tree method applied to computerized prediction of ternary intermetallic compounds

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Decision tree method and atomic parameters were used to find the regularities of the formation of ternary intermetallic compounds in alloy systems. The criteria of formation can be expressed by a group of inequalities with two kinds of atomic parameters Zl (number of valence electrons in the atom of constituent element) and Ri/Rj (ratio of the atomic radius of constituent element i and j) as independent variables. The data of 2238 known ternary alloy systems were used to extract the empirical rules governing the formation of ternary intermetallic compounds, and the facts of ternary compound formation of other 1334 alloy systems were used as samples to test the reliability of the empirical criteria found. The rate of correctness of prediction was found to be nearly 95%. An expert system for ternary intermetallic compound formation was built and some prediction results of the expert system were confirmed.

  7. Applying Computerized-Scoring Models of Written Biological Explanations across Courses and Colleges: Prospects and Limitations

    Science.gov (United States)

    Ha, Minsu; Nehm, Ross H.; Urban-Lurain, Mark; Merrill, John E.

    2011-01-01

    Our study explored the prospects and limitations of using machine-learning software to score introductory biology students’ written explanations of evolutionary change. We investigated three research questions: 1) Do scoring models built using student responses at one university function effectively at another university? 2) How many human-scored student responses are needed to build scoring models suitable for cross-institutional application? 3) What factors limit computer-scoring efficacy, and how can these factors be mitigated? To answer these questions, two biology experts scored a corpus of 2556 short-answer explanations (from biology majors and nonmajors) at two universities for the presence or absence of five key concepts of evolution. Human- and computer-generated scores were compared using kappa agreement statistics. We found that machine-learning software was capable in most cases of accurately evaluating the degree of scientific sophistication in undergraduate majors’ and nonmajors’ written explanations of evolutionary change. In cases in which the software did not perform at the benchmark of “near-perfect” agreement (kappa > 0.80), we located the causes of poor performance and identified a series of strategies for their mitigation. Machine-learning software holds promise as an assessment tool for use in undergraduate biology education, but like most assessment tools, it is also characterized by limitations. PMID:22135372

  8. Status of computerized cognitive testing in aging: a systematic review.

    Science.gov (United States)

    Wild, Katherine; Howieson, Diane; Webbe, Frank; Seelye, Adriana; Kaye, Jeffrey

    2008-11-01

    Early detection of cognitive decline in the elderly has become of heightened importance in parallel with the recent advances in therapeutics. Computerized assessment might be uniquely suited to early detection of changes in cognition in the elderly. We present here a systematic review of the status of computer-based cognitive testing, focusing on detection of cognitive decline in the aging population. All studies purporting to assess or detect age-related changes in cognition or early dementia/mild cognitive impairment by means of computerized testing were included. Each test battery was rated on availability of normative data, level of evidence for test validity and reliability, comprehensiveness, and usability. All published studies relevant to a particular computerized test were read by a minimum of two reviewers, who completed rating forms containing the above mentioned criteria. Of the 18 test batteries identified from the initial search, 11 were appropriate to cognitive testing in the elderly and were subjected to systematic review. Of those 11, five were either developed specifically for application with the elderly or have been used extensively with that population. Even within the computerized testing genre, great variability existed in manner of administration, ranging from fully examiner-administered to fully self-administered. All tests had at least minimal reliability and validity data, commonly reported in peer-reviewed articles. However, level of rigor of validity testing varied widely. All test batteries exhibited some of the strengths of computerized cognitive testing: standardization of administration and stimulus presentation, accurate measures of response latencies, automated comparison in real time with an individual's prior performance as well as with age-related norms, and efficiencies of staffing and cost. Some, such as the Mild Cognitive Impairment Screen, adapted complicated scoring algorithms to enhance the information gathered from

  9. Tomografía de resistividad eléctrica aplicada a la caracterización de sitios contaminados en tambos Electrical resistivity tomography applied to the characterization of contaminated sites at dairies

    Directory of Open Access Journals (Sweden)

    Beatriz N Losinno

    2008-12-01

    Full Text Available La calidad del agua subterránea en los tambos, utilizada para consumo animal, puede tener incidencia en la calidad de la leche, por lo cual es importante conocer el efecto de los lixiviados sobre el suelo y el agua subterránea. El objetivo fue detectar anomalías de conductividad eléctrica (CE en zona no saturada y saturada por medio de la tomografía de resistividad eléctrica, en sitios potencialmente contaminados en dos tambos, uno en Venado Tuerto y otro en Carmen de Areco y su relación con las propiedades físico-químicas del suelo y agua subterránea. En Carmen de Areco, en un suelo franco limoso con la presencia de un horizonte arcilloso (Bt el sitio más comprometido resultó el corral de encierre cercano a la zona de ordeñe, con anomalía de conductividad eléctrica del 60% en la zona no saturada respecto a sondeos testigos, mientras que la zona de alimentación, que periódicamente se traslada de lote, no se vió afectada. En Venado Tuerto, en un suelo franco arenoso de textura más gruesa, la zona de alimentación, con una anomalía del 84% y con una carga animal prolongada en el tiempo y las inmediaciones de la laguna de efluentes, presentaron un alto contenido de sales. En ambos casos la salinidad estuvo asociada con alto contenido de nitratos, fósforo y sulfatos provenientes de los efluentes ganaderos.Groundwater quality at dairies, used for animal consumption, may have incidence on milk quality, for which it is important to know the effect of wastes lixiviation on soil and groundwater. The aim was to detect anomalies of electrical conductivity at non saturated and saturated zone, by means of electrical resistivity tomography, at potentially contaminated sites at two dairies at Venado Tuerto (Santa Fe Province, Argentina and at Carmen de Areco (Buenos Aires Province, Argentina, and its relationship with physico-chemical properties of soil and groundwater. In Carmen de Areco, a silty laomy soil with clay horizon (Bt, the most

  10. Nanoscale tomography in materials science

    Directory of Open Access Journals (Sweden)

    Günter Möbus

    2007-12-01

    Full Text Available In materials science, various techniques for three-dimensional reconstruction of microstructures have been applied successfully for decades, such as X-ray tomography and mechanical sectioning. However, in the last decade the family tree of methods has grown significantly. This is partly through advances in instrumentation. The introduction of the focused ion beam microscope and the transformation of transmission electron microscopy into a multipurpose analytical and structural tool have made major impacts. The main driving force for progress is perhaps the advent of nanotechnology with the need to achieve nanometer-scale resolution and the desire to get a real three-dimensional view of the nanoscale world.

  11. Dynamic Optical Coherence Tomography in Dermatology

    DEFF Research Database (Denmark)

    Ulrich, Martina; Themstrup, Lotte; De Carvalho, Nathalie

    2016-01-01

    Optical coherence tomography (OCT) represents a non-invasive imaging technology, which may be applied to the diagnosis of non-melanoma skin cancer and which has recently been shown to improve the diagnostic accuracy of basal cell carcinoma. Technical developments of OCT continue to expand the app...

  12. Computerized reduction of airborne foil impactor data

    Science.gov (United States)

    Peterson, Bret A.; Musil, Dennis J.; Smith, Paul L.

    1991-01-01

    A new technique for reducing data obtained from a foil impactor carried on the T-28 thunderstorm penetration aircraft is described. The technique employs a video-image processing system that was originally developed for satellite imagery and a computer-reduction program that was originally developed for determining cloud-size distributions to count and size particle impressions on the foil. This eliminates the tedious manual processing that has limited the usefulness of such devices, while at the same time improving objectivity. The technique has been applied to foil data acquired in thunderstorms in the southeastern United States during the Cooperative Huntsville Meteorological Experiment, where most of the particles were at least roughly spherical. Its usefulness for storms in which highly irregular or fragile ice particles predominate has yet to be established.

  13. Three-Dimensional Optical Coherence Tomography (3D OCT) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Applied Science Innovations, Inc. proposes to develop a new tool of 3D optical coherence tomography (OCT) for cellular level imaging at video frame rates and...

  14. Three-Dimensional Optical Coherence Tomography (3D OCT) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Applied Science Innovations, Inc. proposes a new tool of 3D optical coherence tomography (OCT) for cellular level imaging at video frame rates and dramatically...

  15. Detection of drugs and plastic explosives using neutron tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, F.J.O. [Instituto de Engenharia Nuclear (IEN), Rio de Janeiro, RJ (Brazil)], E-mail: fferreira@ien.gov.br; Crispim, V.R; Silva, A.X. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Programa de Engenharia Nuclear], E-mail: ademir@con.ufrj.br, E-mail: verginia@com.ufrj.br

    2007-07-01

    The unique ability of neutrons to image certain elements and isotopes that are either completely undetectable or poorly detected by other Non-Destructive-Assay (NDA) methods makes neutron radiography an important tool for the NDA community. Neutron radiography, like other imaging techniques takes a number of different forms (i.e. / that is film, radioscopic, transfer methods, tomography, etc.) In this work report the Neutron Tomography System developed, which will allow inspections NDA of samples with high efficiency, in terms of minors measure time and the result analysis, and the application for detection of drugs and plastic explosives, which is very important for the combat to the terrorism and drug trafficking. The neutron tomography system developed is third generation. Therefore a rotary table driven by a step motor connected to a computerized motion control system has been installed at the sample position. In parallel to this a suitable electronic imaging device has been designed and can be controlled by a computer in order to synchronize the software the detector and of the rotary table with the aim of an automation of measurements. To obtain 2D tomography image, a system with an electronic imaging system for producing real time neutron radiography. Images are processing digital for cancel random noise effects and to optimize spatial resolution. Finally, using a (ARIEN) algorithm reconstruction of tomography images by finite element maximum entropy. The system was installed adjacent to the exit of the J-9 irradiation channel of the Argonauta Reactor in the Nuclear Engineering Institute (IEN) - which is an organ of the National Nuclear Energy Commission (CNEN - Brazil).The Argonauta reactor operates at 340 watts, being that the characteristics of the neutron beam on the plane of the image: thermal neutron flux 4,46 x10{sup 5} n/cm{sup 2}s. In the tomography assays, several encapsulated samples of paste, rock and cocaine powder and plastic explosives devices

  16. Computerized games to study the development of attention in childhood.

    Science.gov (United States)

    Berger, A; Jones, L; Rothbart, M K; Posner, M I

    2000-05-01

    Children enjoy playing games. We can take advantage of this in the designs of computerized tasks that will engage their interest. These designs also serve to advance the study of chronometric measures, such as manual and saccadic reaction times and event related potentials, with young children. The goals of our method development are (1) to allow for comparable tasks across a wide variety of ages, (2) to make possible comparisons of child performance with data gathered in adult cognitive studies, and (3) to help to support inferences about the development of underlying mechanisms. We have designed a battery of computerized tasks in order to study the development of attention functions of alertness, orienting, and executive control during childhood. Our purpose is to describe each of these tasks in detail and present the results that have been obtained so far. The battery was tested using a sample of 5-year-old children as subjects.

  17. Computerization of Mental Health Integration complexity scores at Intermountain Healthcare.

    Science.gov (United States)

    Oniki, Thomas A; Rodrigues, Drayton; Rahman, Noman; Patur, Saritha; Briot, Pascal; Taylor, David P; Wilcox, Adam B; Reiss-Brennan, Brenda; Cannon, Wayne H

    2014-01-01

    Intermountain Healthcare's Mental Health Integration (MHI) Care Process Model (CPM) contains formal scoring criteria for assessing a patient's mental health complexity as "mild," "medium," or "high" based on patient data. The complexity score attempts to assist Primary Care Physicians in assessing the mental health needs of their patients and what resources will need to be brought to bear. We describe an effort to computerize the scoring. Informatics and MHI personnel collaboratively and iteratively refined the criteria to make them adequately explicit and reflective of MHI objectives. When tested on retrospective data of 540 patients, the clinician agreed with the computer's conclusion in 52.8% of the cases (285/540). We considered the analysis sufficiently successful to begin piloting the computerized score in prospective clinical care. So far in the pilot, clinicians have agreed with the computer in 70.6% of the cases (24/34).

  18. Algorithms for Computerized Fetal Heart Rate Diagnosis with Direct Reporting

    Directory of Open Access Journals (Sweden)

    Kazuo Maeda

    2015-06-01

    Full Text Available Aims: Since pattern classification of fetal heart rate (FHR was subjective and enlarged interobserver difference, objective FHR analysis was achieved with computerized FHR diagnosis. Methods: The computer algorithm was composed of an experts’ knowledge system, including FHR analysis and FHR score calculation, and also of an objective artificial neural network system with software. In addition, a FHR frequency spectrum was studied to detect ominous sinusoidal FHR and the loss of baseline variability related to fetal brain damage. The algorithms were installed in a central-computerized automatic FHR monitoring system, which gave the diagnosis rapidly and directly to the attending doctor. Results: Clinically perinatal mortality decreased significantly and no cerebral palsy developed after introduction of the centralized system. Conclusion: The automatic multichannel FHR monitoring system improved the monitoring, increased the objectivity of FHR diagnosis and promoted clinical results.

  19. Does familiarity with computers affect computerized neuropsychological test performance?

    Science.gov (United States)

    Iverson, Grant L; Brooks, Brian L; Ashton, V Lynn; Johnson, Lynda G; Gualtieri, C Thomas

    2009-07-01

    The purpose of this study was to determine whether self-reported computer familiarity is related to performance on computerized neurocognitive testing. Participants were 130 healthy adults who self-reported whether their computer use was "some" (n = 65) or "frequent" (n = 65). The two groups were individually matched on age, education, sex, and race. All completed the CNS Vital Signs (Gualtieri & Johnson, 2006b) computerized neurocognitive battery. There were significant differences on 6 of the 23 scores, including scores derived from the Symbol-Digit Coding Test, Stroop Test, and the Shifting Attention Test. The two groups were also significantly different on the Psychomotor Speed (Cohen's d = 0.37), Reaction Time (d = 0.68), Complex Attention (d = 0.40), and Cognitive Flexibility (d = 0.64) domain scores. People with "frequent" computer use performed better than people with "some" computer use on some tests requiring rapid visual scanning and keyboard work.

  20. Modern Sequential Analysis and its Applications to Computerized Adaptive Testing

    CERN Document Server

    Bartroff, Jay; Lai, Tze Leung

    2011-01-01

    After a brief review of recent advances in sequential analysis involving sequential generalized likelihood ratio tests, we discuss their use in psychometric testing and extend the asymptotic optimality theory of these sequential tests to the case of sequentially generated experiments, of particular interest in computerized adaptive testing. We then show how these methods can be used to design adaptive mastery tests, which are asymptotically optimal and are also shown to provide substantial improvements over currently used sequential and fixed length tests.

  1. A Fully Computerized Method to Backup the Router Configuration File

    Directory of Open Access Journals (Sweden)

    Ghassan H.Majeed

    2007-01-01

    Full Text Available This paper presents a fully computerized method to backup the router configuration file. The method consists of a friendly graphical interface programmed by Java programming language The proposed method is compared with the two existing methods, namely: TFTP server method and Copy/Paste method. The comparison reveals that the proposed method has many advantages over the existing ones. The proposed method has been implemented on Cisco routers (series 2500, 2600 and 2800

  2. Evaluation of a Computerized Clinical Information System (Micromedex).

    OpenAIRE

    Lundsgaarde, H. P.; Moreshead, G. E.

    1991-01-01

    This paper summarizes data collected as part of a project designed to identify and assess the technical and organizational problems associated with the implementation and evaluation of a Computerized Clinical Information System (CCIS), Micromedex, in three U.S. Department of Veterans Affairs Medical Centers (VAMCs). The study began in 1987 as a national effort to implement decision support technologies in the Veterans Administration Decentralized Hospital Computer Program (DHCP). The specific...

  3. Information integrity and privacy for computerized medical patient records

    Energy Technology Data Exchange (ETDEWEB)

    Gallegos, J.; Hamilton, V.; Gaylor, T.; McCurley, K.; Meeks, T.

    1996-09-01

    Sandia National Laboratories and Oceania, Inc. entered into a Cooperative Research and Development Agreement (CRADA) in November 1993 to provide ``Information Integrity and Privacy for Computerized Medical Patient Records`` (CRADA No. SC93/01183). The main objective of the project was to develop information protection methods that are appropriate for databases of patient records in health information systems. This document describes the findings and alternative solutions that resulted from this CRADA.

  4. Computerized Analysis of MR and Ultrasound Images of Breast Lesions

    Science.gov (United States)

    2001-07-01

    Yearbook of Radiology) 3. Horsch K, Giger ML, Venta LA, Huo Z, Vyborny CJ; Computer-aided diagnosis of breast lesions on ultrasound. Proceedings...International Workshop on Digital Mammography. Toronto, Canada, June, 2000. 4. Horsch K, Giger ML, Venta LA, Vyborny CJ: Automatic segmentation of breast...lesions on ultrasound. Medical Physics (in press). 5. Horsch K, Giger ML, Venta LA, Vyborny CJ: Computerized diagnosis of breast lesions on ultrasound

  5. TBASE: a computerized database for transgenic animals and targeted mutations.

    Science.gov (United States)

    Woychik, R P; Wassom, J S; Kingsbury, D; Jacobson, D A

    1993-05-27

    A computerized database, called TBASE, has been developed to organize and make available information on transgenic animals and targeted mutations by using resources at the Oak Ridge National Laboratory (ORNL) and Johns Hopkins University (JHU). The database is available through the JHU Computational Biology Gopher Server. To ensure that all interested users have access, several mechanisms will be installed to accommodate varying levels of telecommunication network connectivity.

  6. Managing people problems in changing to computerized text processing

    Energy Technology Data Exchange (ETDEWEB)

    Walker, T.R.

    1980-01-01

    Change is always both a promise and a threat. Changing to a computerized text processing system is, from a management viewpoint, mostly a promise; but from an employee viewpoint, mostly a threat. A variety of people problems arise from such a changeover because of the perceived threats involved. Most of these problems can be expected, so that, by proper management, their effects can be reduced or eliminated.

  7. Computerized assessment of pain drawing area: A pilot study

    Directory of Open Access Journals (Sweden)

    Anna Wenngren

    2009-08-01

    Full Text Available Anna Wenngren, Britt-Marie StålnackeDepartment of Community Medicine and Rehabilitation, Umeå University, SwedenAim: To investigate if pain area in patients with chronic pain could be measured by a computerized assessment on previously marked pain drawings on paper figures and to analyze the further application of the method.Methods: Seventy-two patients (54 women and 18 men who were admitted to Umeå University Hospital during 2003 for assessment of chronic pain answered a set of questionnaires (pain intensity on the visual analog scale [VAS], disability on the Disability Rating Index [DRI], life satisfaction on the LiSat-11 and filled in pain drawings on paper figures of the human body. The pain drawings were later analyzed by using computerized assessment.Results: Women marked a greater pain area than men, but the difference was not significant (p = 0.433. No significant difference was shown for the previous seven days between men and women on the VAS (p = 0.914, DRI (p = 0.493, or LiSat-11 (p = 0.124. A statistically significant correlation was found between pain area and VAS for the previous seven days (r = 0.250; p = 0.046. Pain area was statistically significantly correlated to the DRI (r = 0.336; p = 0.014 and close to negatively correlated to the LiSat-11 (r = -0.687; p = 0.057.Conclusion: This pilot study shows that pain drawing area could be measured by a computerized assessment of pain drawings. The method points to the possibility of relating pain area with other instruments. In the present study, an association between the patients’ pain drawing area and pain intensity and between pain area and level of activity was shown.Keywords: musculoskeletal pain, screening, pain drawing, computerized assessment

  8. Geophysical wave tomography

    Science.gov (United States)

    Zhou, Chaoguang

    2000-11-01

    This study is concerned with geophysical wave tomography techniques that include advanced diffraction tomography, traveltime calculation techniques and simultaneous attenuation and velocity tomography approaches. We propose the source independent approximation, the Modified Quasi-Linear approximation and develop a fast and accurate diffraction tomography algorithm that uses this approximation. Since the Modified Quasi-Linear approximation accounts for the scattering fields within scatterers, this tomography algorithm produces better image quality than conventional Born approximation tomography algorithm does with or without the presence of multiple scatterers and can be used to reconstruct images of high contrast objects. Since iteration is not required, this algorithm is efficient. We improve the finite difference traveltime calculation algorithm proposed by Vidale (1990). The bucket theory is utilized in order to enhance the sorting efficiency, which accounts for about ten percent computing time improvement for large velocity models. Snell's law is employed to solve the causality problem analytically, which enables the modified algorithm to compute traveltimes accurately and rapidly for high velocity contrast media. We also develop two simultaneous attenuation and velocity tomography approaches, which use traveltimes and amplitude spectra of the observed data, and discuss some of their applications. One approach is processing geophysical data that come from one single survey and the other deals with the repeated survey cases. These approaches are nonlinear and therefore more accurate than linear tomography. A linear system for wave propagation and constant-Q media are assumed in order to develop the tomography algorithms. These approaches not only produce attenuation and velocity images at the same time but also can be used to infer the physical rock properties, such as the dielectric permittivity, the electric conductivity, and the porosity. A crosshole radar

  9. Monte Carlo Simulation Of Emission Tomography And Other Medical Imaging Techniques

    Science.gov (United States)

    Harrison, Robert L.

    2010-01-01

    An introduction to Monte Carlo simulation of emission tomography. This paper reviews the history and principles of Monte Carlo simulation, then applies these principles to emission tomography using the public domain simulation package SimSET (a Simulation System for Emission Tomography) as an example. Finally, the paper discusses how the methods are modified for X-ray computed tomography and radiotherapy simulations. PMID:20733931

  10. Design of computerized unbalance measuring system

    Energy Technology Data Exchange (ETDEWEB)

    Karunakara, K.; Nambudiri, P.V.V.; Aradhya, S.; Kumar, E.M.; Channakeshava [Central Power Research Inst., Bangalore (India)

    1995-12-31

    In complex network, the connected loads may be of single phase or three phase. Increased trend of traction loads, Arc furnace load and thyristor devices necessitates check for voltage quality. Harmonics, flicker and unbalance are some of the factors influencing the voltage quality. Evaluation of voltage quality and applying correction, if required, are to be made depending upon the situation prevailing in the system. Under certain load conditions like arc furnace, traction and thyristor devices, the unbalance factor may vary every few cycles and for the unbalance correction, devices like static Var compensator (SVC) have to be used. These correcting devices have some time lag to effect corrections, thus measurement based on short time information will not give the true picture. To avoid erroneous conclusions from the short term data, an instrument based on an integrated value over fairly long duration was designed and fabricated by CPRI. This paper discusses about the design and calibration of the instrument and presents typical measured data on an electrical system by using this instrument.

  11. Preoperative computed tomography and scintigraphy to facilitate the detection of accessory spleen in patients with hematologic disorders

    Energy Technology Data Exchange (ETDEWEB)

    Koyanagi, Nobuhiro; Kanematsu, Takashi; Sugimachi, Keizo

    1988-01-01

    Accessory spleens of 1.5 cm in size were preoperatively identified by the combined use of computerized tomography and splenic scintigraphy in two patients with hematologic diseases. After the accessory spleen had been removed from the first patient, who had persistent hereditary spherocytosis and had undergone a splenectomy 15 months before, a postoperative decrease in hyperbilirubinemia was noted. In the other patient who had idiopathic thrombocytopenic purpura, a successful accessory splenectomy was done at the same time as her splenectomy, and was followed by 6 months' complete remission. These events indicate that preoperative investigations using computerized tomography and scintigraphy are indispensable for ruling out an accessory spleen in those patients for whom splenectomy needs to be done in order to alleviate hematologic disorders.

  12. Computerized evaluation method of white matter hyperintensities related to subcortical vascular dementia in brain MR images

    Science.gov (United States)

    Arimura, Hidetaka; Kawata, Yasuo; Yamashita, Yasuo; Magome, Taiki; Ohki, Masafumi; Toyofuku, Fukai; Higashida, Yoshiharu; Tsuchiya, Kazuhiro

    2010-03-01

    We have developed a computerized evaluation method of white matter hyperintensity (WMH) regions for the diagnosis of vascular dementia (VaD) based on magnetic resonance (MR) images, and implemented the proposed method as a graphical interface program. The WMH regions were segmented using either a region growing technique or a level set method, one of which was selected by using a support vector machine. We applied the proposed method to MR images acquired from 10 patients with a diagnosis of VaD. The mean similarity index between WMH regions determined by a manual method and the proposed method was 78.2+/-11.0%. The proposed method could effectively assist neuroradiologists in evaluating WMH regions.

  13. High-resolution Surface Analysis by Microarea Auger Spectroscopy: Computerization and Characterization

    Science.gov (United States)

    Browning, R.

    1986-01-01

    A custom scanning Auger electron microscope (SAM) capable of introducing a 3-5 keV electron beam of several nA into a 30 nm diameter sample area was fitted with a sample introduction system and was fully computerized to be used for materials science research. The method of multispectral Auger imaging was devised and implemented. The instrument was applied to various problems in materials science, including the study of the fiber/matrix interface in a SiC reinforced titanium alloy, the study of SiC whiskers in Al alloy 2124 (in cooperation with NASA-Langley), the study of NiCrAl superalloys (in collaboration with NASA-Lewis), the study of zircalloy specimens (in collaboration with Stanford University), and the microstructure of sintered SiC specimens (in collaboration with NASA-Lewis). The report contains a number of manuscripts submitted for publication on these subjects.

  14. Computerized Design and Generation of Low-noise Helical Gears with Modified Surface Topology

    Science.gov (United States)

    Litvin, F. L.; Chen, N. X.; Lu, J.; Handschuh, R. F.

    1994-01-01

    An approach for design and generation of low-noise helical gears with localized bearing contact is proposed. The approach is applied to double circular arc helical gears and modified involute helical gears. The reduction of noise and vibration is achieved by application of a predesigned parabolic function of transmission errors that is able to absorb a discontinuous linear function of transmission errors caused by misalignment. The localization of the bearing contact is achieved by the mismatch of pinion-gear tooth surfaces. Computerized simulation of meshing and contact of the designed gears demonstrated that the proposed approach will produce a pair of gears that has a parabolic transmission error function even when misalignment is present. Numerical examples for illustration of the developed approach are given.

  15. Optical coherence tomography in late solar retinopathy

    Directory of Open Access Journals (Sweden)

    Janković Aleksandar

    2011-01-01

    Full Text Available Introduction. Solar retinopathy refers to retinal injury induced by direct or indirect solar viewing. Case report. We presented a patient who had observed partial solar eclipse 51 year before. He had bilaterally decreased vision and scar of the macular region at the time of presentation. The basic diagnostic tool applied in the presented patient, optical coherence tomography, showed hyporeflexivity of the outer retina in the segment of retinal pigment epithelialphotoreceptors complex with atrophy and thinning of the foveolar region. Conclusion. Optical coherence tomography is a powerful, non-invasive diagnostic tool which can ease the diagnosis and estimate the level and nature of the macular region damage.

  16. Reflecting on the ethical administration of computerized medical records

    Science.gov (United States)

    Collmann, Jeff R.

    1995-05-01

    This presentation examines the ethical issues raised by computerized image management and communication systems (IMAC), the ethical principals that should guide development of policies, procedures and practices for IMACS systems, and who should be involved in developing a hospital's approach to these issues. The ready access of computerized records creates special hazards of which hospitals must beware. Hospitals must maintain confidentiality of patient's records while making records available to authorized users as efficiently as possible. The general conditions of contemporary health care undermine protecting the confidentiality of patient record. Patients may not provide health care institutions with information about themselves under conditions of informed consent. The field of information science must design sophisticated systems of computer security that stratify access, create audit trails on data changes and system use, safeguard patient data from corruption, and protect the databases from outside invasion. Radiology professionals must both work with information science experts in their own hospitals to create institutional safeguards and include the adequacy of security measures as a criterion for evaluating PACS systems. New policies and procedures on maintaining computerized patient records must be developed that obligate all members of the health care staff, not just care givers. Patients must be informed about the existence of computerized medical records, the rules and practices that govern their dissemination and given the opportunity to give or withhold consent for their use. Departmental and hospital policies on confidentiality should be reviewed to determine if revisions are necessary to manage computer-based records. Well developed discussions of the ethical principles and administrative policies on confidentiality and informed consent and of the risks posed by computer-based patient records systems should be included in initial and continuing

  17. Photoelastic tomography as hybrid mechanics

    Directory of Open Access Journals (Sweden)

    Errapart A.

    2010-06-01

    Full Text Available Photoelastic tomography is a non-destructive method of 3D stress analysis. It permits determination of normal stress distribution in an arbitrary section of a 3D test object. In case of axial symmetry also the shear stress distribution can be determined directly from the measurement data. To determine also the other stress components one can use equations of the theory of elasticity. Such a combined application of experimental measurements and numerical handling of the equations of the theory of elasticity is named hybrid mechanics. It is shown that if stresses are due to external loads, the hybrid mechanics algorithm is based on the equations of equilibrium and compatibility. In the case of the measurement of the residual stress in glass the compatibility equation can not be applied. In this case a new relationship of axisymmetric thermoelasticity, the generalized sum rule can be applied.

  18. Photoelastic tomography as hybrid mechanics

    Science.gov (United States)

    Aben, H.; Ainola, L.; Errapart, A.

    2010-06-01

    Photoelastic tomography is a non-destructive method of 3D stress analysis. It permits determination of normal stress distribution in an arbitrary section of a 3D test object. In case of axial symmetry also the shear stress distribution can be determined directly from the measurement data. To determine also the other stress components one can use equations of the theory of elasticity. Such a combined application of experimental measurements and numerical handling of the equations of the theory of elasticity is named hybrid mechanics. It is shown that if stresses are due to external loads, the hybrid mechanics algorithm is based on the equations of equilibrium and compatibility. In the case of the measurement of the residual stress in glass the compatibility equation can not be applied. In this case a new relationship of axisymmetric thermoelasticity, the generalized sum rule can be applied.

  19. Demonstration of the route of embryo migration in retroperitoneal ectopic pregnancy using contrast-enhanced computed tomography.

    Science.gov (United States)

    Liang, Changhu; Li, Xueli; Zhao, Bin; Du, Yinglin; Xu, Shifeng

    2014-03-01

    Retroperitoneal abdominal pregnancy is exceptionally rare. An unusual retroperitoneal pregnancy has a high risk of severe bleeding. Abdominal ultrasonography and whole abdominal computerized tomography scanning should be performed for the early diagnosis of ectopic pregnancy. A case of retroperitoneal ectopic pregnancy located very close to large retroperitoneal blood vessels and treated with resection is presented. Many unusual features of retroperitoneal ectopic pregnancy were highlighted as providing further evidence in support of the main proposed embryo migration mechanism via lymphatic vessels.

  20. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... tomography (CT) scan. View full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. ...