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Sample records for tomography quantitative effects

  1. Quantitative cardiac computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Thelen, M.; Dueber, C.; Wolff, P.; Erbel, R.; Hoffmann, T.

    1985-06-01

    The scope and limitations of quantitative cardiac CT have been evaluated in a series of experimental and clinical studies. The left ventricular muscle mass was estimated by computed tomography in 19 dogs (using volumetric methods, measurements in two axes and planes and reference volume). There was good correlation with anatomical findings. The enddiastolic volume of the left ventricle was estimated in 22 patients with cardiomyopathies; using angiography as a reference, CT led to systematic under-estimation. It is also shown that ECG-triggered magnetic resonance tomography results in improved visualisation and may be expected to improve measurements of cardiac morphology.

  2. Quantitative inspection by computerized tomography

    International Nuclear Information System (INIS)

    Lopes, R.T.; Assis, J.T. de; Jesus, E.F.O. de

    1989-01-01

    The computerized Tomography (CT) is a method of nondestructive testing, that furnish quantitative information, that permit the detection and accurate localization of defects, internal dimension measurement, and, measurement and chart of the density distribution. The CT technology is much versatile, not presenting restriction in relation to form, size or composition of the object. A tomographic system, projected and constructed in our laboratory is presented. The applications and limitation of this system, illustrated by tomographyc images, are shown. (V.R.B.)

  3. Quantitative biological measurement in Transmission Electron Tomography

    International Nuclear Information System (INIS)

    Mantell, Judith M; Verkade, Paul; Arkill, Kenton P

    2012-01-01

    It has been known for some time that biological sections shrink in the transmission electron microscope from exposure to the electron beam. This phenomenon is especially important in Electron Tomography (ET). The effect on shrinkage of parameters such as embedding medium or sample type is less well understood. In addition anisotropic area shrinkage has largely been ignored. The intention of this study is to explore the shrinkage on a number of samples ranging in thickness from 200 nm to 500 nm. A protocol was developed to determine the shrinkage in area and thickness using the gold fiducials used in electron tomography. In brief: Using low dose philosophy on the section, a focus area was used prior to a separate virgin study area for a series of known exposures on a tilted sample. The shrinkage was determined by measurements on the gold beads from both sides of the section as determined by a confirmatory tomogram. It was found that the shrinkage in area (approximately to 90-95% of the original) and the thickness (approximately 65% of the original at most) agreed with pervious authors, but that a lmost all the shrinkage was in the first minute and that although the direction of the in-plane shrinkage (in x and y) was sometimes uneven the end result was consistent. It was observed, in general, that thinner samples showed more percentage shrinkage than thicker ones. In conclusion, if direct quantitative measurements are required then the protocol described should be used for all areas studied.

  4. Quantitative biological measurement in Transmission Electron Tomography

    Science.gov (United States)

    Mantell, Judith M.; Verkade, Paul; Arkill, Kenton P.

    2012-07-01

    It has been known for some time that biological sections shrink in the transmission electron microscope from exposure to the electron beam. This phenomenon is especially important in Electron Tomography (ET). The effect on shrinkage of parameters such as embedding medium or sample type is less well understood. In addition anisotropic area shrinkage has largely been ignored. The intention of this study is to explore the shrinkage on a number of samples ranging in thickness from 200 nm to 500 nm. A protocol was developed to determine the shrinkage in area and thickness using the gold fiducials used in electron tomography. In brief: Using low dose philosophy on the section, a focus area was used prior to a separate virgin study area for a series of known exposures on a tilted sample. The shrinkage was determined by measurements on the gold beads from both sides of the section as determined by a confirmatory tomogram. It was found that the shrinkage in area (approximately to 90-95% of the original) and the thickness (approximately 65% of the original at most) agreed with pervious authors, but that a lmost all the shrinkage was in the first minute and that although the direction of the in-plane shrinkage (in x and y) was sometimes uneven the end result was consistent. It was observed, in general, that thinner samples showed more percentage shrinkage than thicker ones. In conclusion, if direct quantitative measurements are required then the protocol described should be used for all areas studied.

  5. Effect of Hydroxychloroquine on the Retinal Layers: A Quantitative Evaluation with Spectral-Domain Optical Coherence Tomography

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    Hasim Uslu

    2016-01-01

    Full Text Available Purpose. To evaluate the effect of hydroxychloroquine on retinal pigment epithelium- (RPE- Bruch’s membrane complex, photoreceptor outer segment, and macular ganglion cell-inner plexiform layer (GCIPL thicknesses using spectral-domain optical coherence tomography (SD-OCT. Methods. In this prospective case-control study, 51 eyes of 51 hydroxychloroquine patients and 30 eyes of 30 healthy subjects were included. High-quality images were obtained using a Cirrus HD-OCT with 5-line raster mode; the photoreceptor inner segment (IS and outer segment (OS, sum of the segments (IS + OS, and RPE-Bruch’s membrane complex were analyzed. Results. The thicknesses of the IS + OS and OS layers were significantly lower in the hydroxychloroquine subjects compared to the control subjects (P<0.05. RPE-Bruch’s membrane complex thicknesses were significantly higher in the hydroxychloroquine subjects than for those of the control subjects (P<0.05. The minimum and temporal-inferior macular GCIPL thicknesses were significantly different between the patients with hydroxychloroquine use and the control subjects (P=0.04 and P=0.03, resp.. Conclusions. The foveal photoreceptor OS thinning, loss of GCIPL, and RPE-Bruch’s membrane thickening were detected in patients with hydroxychloroquine therapy. This quantitative approach using SD-OCT images may have important implications to use as an early indicator of retinal toxicity without any visible signs of hydroxychloroquine retinopathy.

  6. Quantitative tomography simulations and reconstruction algorithms

    International Nuclear Information System (INIS)

    Martz, H.E.; Aufderheide, M.B.; Goodman, D.; Schach von Wittenau, A.; Logan, C.; Hall, J.; Jackson, J.; Slone, D.

    2000-01-01

    X-ray, neutron and proton transmission radiography and computed tomography (CT) are important diagnostic tools that are at the heart of LLNL's effort to meet the goals of the DOE's Advanced Radiography Campaign. This campaign seeks to improve radiographic simulation and analysis so that radiography can be a useful quantitative diagnostic tool for stockpile stewardship. Current radiographic accuracy does not allow satisfactory separation of experimental effects from the true features of an object's tomographically reconstructed image. This can lead to difficult and sometimes incorrect interpretation of the results. By improving our ability to simulate the whole radiographic and CT system, it will be possible to examine the contribution of system components to various experimental effects, with the goal of removing or reducing them. In this project, we are merging this simulation capability with a maximum-likelihood (constrained-conjugate-gradient-CCG) reconstruction technique yielding a physics-based, forward-model image-reconstruction code. In addition, we seek to improve the accuracy of computed tomography from transmission radiographs by studying what physics is needed in the forward model. During FY 2000, an improved version of the LLNL ray-tracing code called HADES has been coupled with a recently developed LLNL CT algorithm known as CCG. The problem of image reconstruction is expressed as a large matrix equation relating a model for the object being reconstructed to its projections (radiographs). Using a constrained-conjugate-gradient search algorithm, a maximum likelihood solution is sought. This search continues until the difference between the input measured radiographs or projections and the simulated or calculated projections is satisfactorily small

  7. TU-F-CAMPUS-J-05: Effect of Uncorrelated Noise Texture On Computed Tomography Quantitative Image Features

    International Nuclear Information System (INIS)

    Oliver, J; Budzevich, M; Moros, E; Zhang, G; Hunt, D

    2015-01-01

    Purpose: To investigate the relationship between quantitative image features (i.e. radiomics) and statistical fluctuations (i.e. electronic noise) in clinical Computed Tomography (CT) using the standardized American College of Radiology (ACR) CT accreditation phantom and patient images. Methods: Three levels of uncorrelated Gaussian noise were added to CT images of phantom and patients (20) acquired in static mode and respiratory tracking mode. We calculated the noise-power spectrum (NPS) of the original CT images of the phantom, and of the phantom images with added Gaussian noise with means of 50, 80, and 120 HU. Concurrently, on patient images (original and noise-added images), image features were calculated: 14 shape, 19 intensity (1st order statistics from intensity volume histograms), 18 GLCM features (2nd order statistics from grey level co-occurrence matrices) and 11 RLM features (2nd order statistics from run-length matrices). These features provide the underlying structural information of the images. GLCM (size 128x128) was calculated with a step size of 1 voxel in 13 directions and averaged. RLM feature calculation was performed in 13 directions with grey levels binning into 128 levels. Results: Adding the electronic noise to the images modified the quality of the NPS, shifting the noise from mostly correlated to mostly uncorrelated voxels. The dramatic increase in noise texture did not affect image structure/contours significantly for patient images. However, it did affect the image features and textures significantly as demonstrated by GLCM differences. Conclusion: Image features are sensitive to acquisition factors (simulated by adding uncorrelated Gaussian noise). We speculate that image features will be more difficult to detect in the presence of electronic noise (an uncorrelated noise contributor) or, for that matter, any other highly correlated image noise. This work focuses on the effect of electronic, uncorrelated, noise and future work shall

  8. Quality control in quantitative computed tomography

    International Nuclear Information System (INIS)

    Jessen, K.A.; Joergensen, J.

    1989-01-01

    Computed tomography (CT) has for several years been an indispensable tool in diagnostic radiology, but it is only recently that extraction of quantitative information from CT images has been of practical clinical value. Only careful control of the scan parameters, and especially the scan geometry, allows useful information to be obtained; and it can be demonstrated by simple phantom measurements how sensitive a CT system can be to variations in size, shape and position of the phantom in the gantry aperture. Significant differences exist between systems that are not manifested in normal control of image quality and general performance tests. Therefore an actual system has to be analysed for its suitability for quantitative use of the images before critical clinical applications are justified. (author)

  9. Effect of smoking cessation on quantitative computed tomography in smokers at risk in a lung cancer screening population

    Energy Technology Data Exchange (ETDEWEB)

    Jobst, Bertram J.; Eichinger, Monika; Wielpuetz, Mark O. [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); Translational Lung Research Centre Heidelberg (TLRC), Member of the German Lung Research Centre (DZL), Heidelberg (Germany); Thoraxklinik at the University of Heidelberg, Department of Diagnostic and Interventional Radiology with Nuclear Medicine, Heidelberg (Germany); German Cancer Research Center (DKFZ), Department of Radiology, Heidelberg (Germany); Weinheimer, Oliver; Trauth, Mila; Kauczor, Hans-Ulrich [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); Translational Lung Research Centre Heidelberg (TLRC), Member of the German Lung Research Centre (DZL), Heidelberg (Germany); Thoraxklinik at the University of Heidelberg, Department of Diagnostic and Interventional Radiology with Nuclear Medicine, Heidelberg (Germany); Becker, Nikolaus; Motsch, Erna; Gross, Marie-Luise; Eigentopf, Anke [German Cancer Research Centre (DKFZ Heidelberg), Division of Cancer Epidemiology, Heidelberg (Germany); Tremper, Jan; Delorme, Stefan [German Cancer Research Center (DKFZ), Department of Radiology, Heidelberg (Germany)

    2018-02-15

    To longitudinally evaluate effects of smoking cessation on quantitative CT in a lung cancer screening cohort of heavy smokers over 4 years. After 4 years, low-dose chest CT was available for 314 long-term ex-smokers (ES), 404 continuous smokers (CS) and 39 recent quitters (RQ) who quitted smoking within 2 years after baseline CT. CT acquired at baseline and after 3 and 4 years was subjected to well-evaluated densitometry software, computing mean lung density (MLD) and 15th percentile of the lung density histogram (15TH). At baseline, active smokers showed significantly higher MLD and 15TH (-822±35 and -936±25 HU, respectively) compared to ES (-831±31 and -947±22 HU, p<0.01-0.001). After 3 years, CS again had significantly higher MLD and 15TH (-801±29 and -896±23 HU) than ES (-808±27 and -906±20 HU, p<0.01-0.001) but also RQ (-813±20 and -909±15 HU, p<0.05-0.001). Quantitative CT parameters did not change significantly after 4 years. Importantly, smoking status independently predicted MLD at baseline and year 3 (p<0.001) in multivariate analysis. On quantitative CT, lung density is higher in active smokers than ex-smokers, and sustainably decreases after smoking cessation, reflecting smoking-induced inflammation. Interpretations of quantitative CT data within clinical trials should consider smoking status. (orig.)

  10. Effect of smoking cessation on quantitative computed tomography in smokers at risk in a lung cancer screening population

    International Nuclear Information System (INIS)

    Jobst, Bertram J.; Eichinger, Monika; Wielpuetz, Mark O.; Weinheimer, Oliver; Trauth, Mila; Kauczor, Hans-Ulrich; Becker, Nikolaus; Motsch, Erna; Gross, Marie-Luise; Eigentopf, Anke; Tremper, Jan; Delorme, Stefan

    2018-01-01

    To longitudinally evaluate effects of smoking cessation on quantitative CT in a lung cancer screening cohort of heavy smokers over 4 years. After 4 years, low-dose chest CT was available for 314 long-term ex-smokers (ES), 404 continuous smokers (CS) and 39 recent quitters (RQ) who quitted smoking within 2 years after baseline CT. CT acquired at baseline and after 3 and 4 years was subjected to well-evaluated densitometry software, computing mean lung density (MLD) and 15th percentile of the lung density histogram (15TH). At baseline, active smokers showed significantly higher MLD and 15TH (-822±35 and -936±25 HU, respectively) compared to ES (-831±31 and -947±22 HU, p<0.01-0.001). After 3 years, CS again had significantly higher MLD and 15TH (-801±29 and -896±23 HU) than ES (-808±27 and -906±20 HU, p<0.01-0.001) but also RQ (-813±20 and -909±15 HU, p<0.05-0.001). Quantitative CT parameters did not change significantly after 4 years. Importantly, smoking status independently predicted MLD at baseline and year 3 (p<0.001) in multivariate analysis. On quantitative CT, lung density is higher in active smokers than ex-smokers, and sustainably decreases after smoking cessation, reflecting smoking-induced inflammation. Interpretations of quantitative CT data within clinical trials should consider smoking status. (orig.)

  11. Effects of calibration methods on quantitative material decomposition in photon-counting spectral computed tomography using a maximum a posteriori estimator.

    Science.gov (United States)

    Curtis, Tyler E; Roeder, Ryan K

    2017-10-01

    Advances in photon-counting detectors have enabled quantitative material decomposition using multi-energy or spectral computed tomography (CT). Supervised methods for material decomposition utilize an estimated attenuation for each material of interest at each photon energy level, which must be calibrated based upon calculated or measured values for known compositions. Measurements using a calibration phantom can advantageously account for system-specific noise, but the effect of calibration methods on the material basis matrix and subsequent quantitative material decomposition has not been experimentally investigated. Therefore, the objective of this study was to investigate the influence of the range and number of contrast agent concentrations within a modular calibration phantom on the accuracy of quantitative material decomposition in the image domain. Gadolinium was chosen as a model contrast agent in imaging phantoms, which also contained bone tissue and water as negative controls. The maximum gadolinium concentration (30, 60, and 90 mM) and total number of concentrations (2, 4, and 7) were independently varied to systematically investigate effects of the material basis matrix and scaling factor calibration on the quantitative (root mean squared error, RMSE) and spatial (sensitivity and specificity) accuracy of material decomposition. Images of calibration and sample phantoms were acquired using a commercially available photon-counting spectral micro-CT system with five energy bins selected to normalize photon counts and leverage the contrast agent k-edge. Material decomposition of gadolinium, calcium, and water was performed for each calibration method using a maximum a posteriori estimator. Both the quantitative and spatial accuracy of material decomposition were most improved by using an increased maximum gadolinium concentration (range) in the basis matrix calibration; the effects of using a greater number of concentrations were relatively small in

  12. Quantitative computed tomography for measuring bone mineral content

    International Nuclear Information System (INIS)

    Felsenberg, D.; Kalender, W.A.; Banzer, D.; Schmilinsky, G.; Heyse, M.; Fischer, E.; Schneider, U.; Siemens A.G., Erlangen; Krankenhaus Zehlendorf, Berlin

    1988-01-01

    Quantitative computed tomography (QCT) for measuring bone mineral content of lumbar vertebrae is increasingly used internationally. The effect of using conventional CT (single energy CT, SE-CT) and dual energy CT (DE-CT) on reproducibility has been examined. We defined a standard measurement protocol, which automatically evaluates a calibration phantom. This should ensure an in vivo reproducibility of 1 to 2%. Reference data, which has been obtained with this protocol from 113 normal subjects, using SE-CT ad DE-CT, are presented. (orig.) [de

  13. Quantitative damage imaging using Lamb wave diffraction tomography

    International Nuclear Information System (INIS)

    Zhang Hai-Yan; Ruan Min; Zhu Wen-Fa; Chai Xiao-Dong

    2016-01-01

    In this paper, we investigate the diffraction tomography for quantitative imaging damages of partly through-thickness holes with various shapes in isotropic plates by using converted and non-converted scattered Lamb waves generated numerically. Finite element simulations are carried out to provide the scattered wave data. The validity of the finite element model is confirmed by the comparison of scattering directivity pattern (SDP) of circle blind hole damage between the finite element simulations and the analytical results. The imaging method is based on a theoretical relation between the one-dimensional (1D) Fourier transform of the scattered projection and two-dimensional (2D) spatial Fourier transform of the scattering object. A quantitative image of the damage is obtained by carrying out the 2D inverse Fourier transform of the scattering object. The proposed approach employs a circle transducer network containing forward and backward projections, which lead to so-called transmission mode (TMDT) and reflection mode diffraction tomography (RMDT), respectively. The reconstructed results of the two projections for a non-converted S0 scattered mode are investigated to illuminate the influence of the scattering field data. The results show that Lamb wave diffraction tomography using the combination of TMDT and RMDT improves the imaging effect compared with by using only the TMDT or RMDT. The scattered data of the converted A0 mode are also used to assess the performance of the diffraction tomography method. It is found that the circle and elliptical shaped damages can still be reasonably identified from the reconstructed images while the reconstructed results of other complex shaped damages like crisscross rectangles and racecourse are relatively poor. (special topics)

  14. Quantitative contrast-enhanced optical coherence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Winetraub, Yonatan; SoRelle, Elliott D. [Molecular Imaging Program at Stanford, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Bio-X Program, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Biophysics Program, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Department of Structural Biology, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Liba, Orly [Molecular Imaging Program at Stanford, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Bio-X Program, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Department of Structural Biology, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Department of Electrical Engineering, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Zerda, Adam de la [Molecular Imaging Program at Stanford, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Bio-X Program, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Biophysics Program, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Department of Structural Biology, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States); Department of Electrical Engineering, Stanford University, 299 Campus Drive, Stanford, California 94305 (United States)

    2016-01-11

    We have developed a model to accurately quantify the signals produced by exogenous scattering agents used for contrast-enhanced Optical Coherence Tomography (OCT). This model predicts distinct concentration-dependent signal trends that arise from the underlying physics of OCT detection. Accordingly, we show that real scattering particles can be described as simplified ideal scatterers with modified scattering intensity and concentration. The relation between OCT signal and particle concentration is approximately linear at concentrations lower than 0.8 particle per imaging voxel. However, at higher concentrations, interference effects cause signal to increase with a square root dependence on the number of particles within a voxel. Finally, high particle concentrations cause enough light attenuation to saturate the detected signal. Predictions were validated by comparison with measured OCT signals from gold nanorods (GNRs) prepared in water at concentrations ranging over five orders of magnitude (50 fM to 5 nM). In addition, we validated that our model accurately predicts the signal responses of GNRs in highly heterogeneous scattering environments including whole blood and living animals. By enabling particle quantification, this work provides a valuable tool for current and future contrast-enhanced in vivo OCT studies. More generally, the model described herein may inform the interpretation of detected signals in modalities that rely on coherence-based detection or are susceptible to interference effects.

  15. Quantitative computed tomography evaluation of pulmonary disease

    DEFF Research Database (Denmark)

    McEvoy, Fintan; Buelund, Lene Elisabeth; Strathe, Anders Bjerring

    2009-01-01

    Objective assessment of pulmonary disease from computed tomography (CT) examinations is desirable but difficult. When such assessments can be made, it is important that they are related to some part of the pathophysiologic process present.......Objective assessment of pulmonary disease from computed tomography (CT) examinations is desirable but difficult. When such assessments can be made, it is important that they are related to some part of the pathophysiologic process present....

  16. Toward quantitative core-loss EFTEM tomography

    International Nuclear Information System (INIS)

    Jin-Phillipp, N.Y.; Koch, C.T.; Aken, P.A. van

    2011-01-01

    Core-loss EFTEM tomography provides three-dimensional structural and chemical information. Multiple inelastic scattering occurring in thick specimens as well as orientation-dependent diffraction contrast due to multiple elastic scattering, however, often limit its applications. After demonstrating the capability of core-loss EFTEM tomography to reconstruct just a few monolayers thin carbon layer covering a Fe catalyst particle we discuss its application to thicker samples. We propose an approximate multiple-scattering correction method based on the use of zero-loss images and apply it successfully to copper whiskers, providing a significant improvement of the reconstructed 3D elemental distribution. We conclude this paper by a general discussion on experimental parameters affecting the accuracy of EFTEM 3D elemental mapping. -- Research highlights: → EFTEM 3D elemental mapping has been applied to a catalyst particle from which a CNT has grown and a copper whisker. → Correction of multiple inelastic scattering shows significant improvements in the reconstruction of 3D elemental maps. → Experimental parameters affecting the accuracy of EFTEM 3D elemental mapping are discussed.

  17. Quantitative Tomography for Continuous Variable Quantum Systems

    Science.gov (United States)

    Landon-Cardinal, Olivier; Govia, Luke C. G.; Clerk, Aashish A.

    2018-03-01

    We present a continuous variable tomography scheme that reconstructs the Husimi Q function (Wigner function) by Lagrange interpolation, using measurements of the Q function (Wigner function) at the Padua points, conjectured to be optimal sampling points for two dimensional reconstruction. Our approach drastically reduces the number of measurements required compared to using equidistant points on a regular grid, although reanalysis of such experiments is possible. The reconstruction algorithm produces a reconstructed function with exponentially decreasing error and quasilinear runtime in the number of Padua points. Moreover, using the interpolating polynomial of the Q function, we present a technique to directly estimate the density matrix elements of the continuous variable state, with only a linear propagation of input measurement error. Furthermore, we derive a state-independent analytical bound on this error, such that our estimate of the density matrix is accompanied by a measure of its uncertainty.

  18. Quantitative Tomography for Continuous Variable Quantum Systems.

    Science.gov (United States)

    Landon-Cardinal, Olivier; Govia, Luke C G; Clerk, Aashish A

    2018-03-02

    We present a continuous variable tomography scheme that reconstructs the Husimi Q function (Wigner function) by Lagrange interpolation, using measurements of the Q function (Wigner function) at the Padua points, conjectured to be optimal sampling points for two dimensional reconstruction. Our approach drastically reduces the number of measurements required compared to using equidistant points on a regular grid, although reanalysis of such experiments is possible. The reconstruction algorithm produces a reconstructed function with exponentially decreasing error and quasilinear runtime in the number of Padua points. Moreover, using the interpolating polynomial of the Q function, we present a technique to directly estimate the density matrix elements of the continuous variable state, with only a linear propagation of input measurement error. Furthermore, we derive a state-independent analytical bound on this error, such that our estimate of the density matrix is accompanied by a measure of its uncertainty.

  19. Quantitative computed tomography in measurement of vertebral trabecular bone mass

    International Nuclear Information System (INIS)

    Nilsson, M.; Johnell, O.; Jonsson, K.; Redlund-Johnell, I.

    1988-01-01

    Measurement of bone mineral concentration (BMC) can be done by several modalities. Quantitative computed tomography (QCT) can be used for measurements at different sites and with different types of bone (trabecular-cortical). This study presents a modified method reducing the influence of fat. Determination of BMC was made from measurements with single-energy computed tomography (CT) of the mean Hounsfield number in the trabecular part of the L1 vertebra. The method takes into account the age-dependent composition of the trabecular part of the vertebra. As the amount of intravertebral fat increases with age, the effective atomic number for these parts decreases. This results in a non-linear calibration curve for single-energy CT. Comparison of BMC values using the non-linear calibration curve or the traditional linear calibration with those obtained with a pixel-by-pixel based electron density calculation method (theoretically better) showed results clearly in favor of the non-linear method. The material consisted of 327 patients aged 6 to 91 years, of whom 197 were considered normal. The normal data show a sharp decrease in trabecular bone after the age of 50 in women. In men a slower decrease was found. The vertebrae were larger in men than in women. (orig.)

  20. Bone densitometry in healthy cats by quantitative computed tomography

    International Nuclear Information System (INIS)

    Oliveira, D.C.; Costa, L.A.V.S.; Teixeira, M.W.; Costa, F.S.; Cardoso, M.J.L.

    2012-01-01

    The radiodensity of the trabecular bone of the lumbar vertebrae in 16 healthy adult cats was studied using quantitative computed tomography (QCT). The average radiodensity of the trabecular bone of the second lumbar vertebra was 436.1 +- 42.1 Hounsfield units. However, there was a nonhomogeneous radiodensity distribution of the vertebral body. (author)

  1. The APOSTEL recommendations for reporting quantitative optical coherence tomography studies

    DEFF Research Database (Denmark)

    Cruz-Herranz, Andrés; Balk, Lisanne J; Oberwahrenbrock, Timm

    2016-01-01

    OBJECTIVE: To develop consensus recommendations for reporting of quantitative optical coherence tomography (OCT) study results. METHODS: A panel of experienced OCT researchers (including 11 neurologists, 2 ophthalmologists, and 2 neuroscientists) discussed requirements for performing and reporting...... quantitative analyses of retinal morphology and developed a list of initial recommendations based on experience and previous studies. The list of recommendations was subsequently revised during several meetings of the coordinating group. RESULTS: We provide a 9-point checklist encompassing aspects deemed...... relevant when reporting quantitative OCT studies. The areas covered are study protocol, acquisition device, acquisition settings, scanning protocol, funduscopic imaging, postacquisition data selection, postacquisition data analysis, recommended nomenclature, and statistical analysis. CONCLUSIONS...

  2. Distal radius plate of CFR-PEEK has minimal effect compared to titanium plates on bone parameters in high-resolution peripheral quantitative computed tomography: a pilot study.

    Science.gov (United States)

    de Jong, Joost J A; Lataster, Arno; van Rietbergen, Bert; Arts, Jacobus J; Geusens, Piet P; van den Bergh, Joop P W; Willems, Paul C

    2017-02-27

    Carbon-fiber-reinforced poly-ether-ether-ketone (CFR-PEEK) has superior radiolucency compared to other orthopedic implant materials, e.g. titanium or stainless steel, thus allowing metal-artifact-free postoperative monitoring by computed tomography (CT). Recently, high-resolution peripheral quantitative CT (HRpQCT) proved to be a promising technique to monitor the recovery of volumetric bone mineral density (vBMD), micro-architecture and biomechanical parameters in stable conservatively treated distal radius fractures. When using HRpQCT to monitor unstable distal radius fractures that require volar distal radius plating for fixation, radiolucent CFR-PEEK plates may be a better alternative to currently used titanium plates to allow for reliable assessment. In this pilot study, we assessed the effect of a volar distal radius plate made from CFR-PEEK on bone parameters obtained from HRpQCT in comparison to two titanium plates. Plates were instrumented in separate cadaveric human fore-arms (n = 3). After instrumentation and after removal of the plates duplicate HRpQCT scans were made of the region covered by the plate. HRpQCT images were visually checked for artifacts. vBMD, micro-architectural and biomechanical parameters were calculated, and compared between the uninstrumented and instrumented radii. No visible image artifacts were observed in the CFR-PEEK plate instrumented radius, and errors in bone parameters ranged from -3.2 to 2.6%. In the radii instrumented with the titanium plates, severe image artifacts were observed and errors in bone parameters ranged between -30.2 and 67.0%. We recommend using CFR-PEEK plates in longitudinal in vivo studies that monitor the healing process of unstable distal radius fractures treated operatively by plating or bone graft ingrowth.

  3. Clinical evaluation of iterative reconstruction (ordered-subset expectation maximization) in dynamic positron emission tomography: quantitative effects on kinetic modeling with N-13 ammonia in healthy subjects

    DEFF Research Database (Denmark)

    Hove, Jens D; Rasmussen, Rune; Freiberg, Jacob

    2008-01-01

    BACKGROUND: The purpose of this study was to investigate the quantitative properties of ordered-subset expectation maximization (OSEM) on kinetic modeling with nitrogen 13 ammonia compared with filtered backprojection (FBP) in healthy subjects. METHODS AND RESULTS: Cardiac N-13 ammonia positron...... emission tomography (PET) studies from 20 normal volunteers at rest and during dipyridamole stimulation were analyzed. Image data were reconstructed with either FBP or OSEM. FBP- and OSEM-derived input functions and tissue curves were compared together with the myocardial blood flow and spillover values...... and OSEM flow values were observed with a flow underestimation of 45% (rest/dipyridamole) in the septum and of 5% (rest) and 15% (dipyridamole) in the lateral myocardial wall. CONCLUSIONS: OSEM reconstruction of myocardial perfusion images with N-13 ammonia and PET produces high-quality images for visual...

  4. Clinical evaluation of iterative reconstruction (ordered-subset expectation maximization) in dynamic positron emission tomography: quantitative effects on kinetic modeling with N-13 ammonia in healthy subjects

    DEFF Research Database (Denmark)

    Hove, Jens Dahlgaard; Rasmussen, R.; Freiberg, J.

    2008-01-01

    emission tomography (PET) studies from 20 normal volunteers at rest and during dipyridamole stimulation were analyzed. Image data were reconstructed with either FBP or OSEM. FBP- and OSEM-derived input functions and tissue curves were compared together with the myocardial blood flow and spillover values...... and OSEM flow values were observed with a flow underestimation of 45% (rest/dipyridamole) in the septum and of 5% (rest) and 15% (dipyridamole) in the lateral myocardial wall. CONCLUSIONS: OSEM reconstruction of myocardial perfusion images with N-13 ammonia and PET produces high-quality images for visual...... interpretation. However, compared with FBP, OSEM is associated with substantial underestimation of perfusion on quantitative imaging. Our findings indicate that OSEM should be used with precaution in clinical PET studies Udgivelsesdato: 2008/7...

  5. Progress towards in vitro quantitative imaging of human femur using compound quantitative ultrasonic tomography

    International Nuclear Information System (INIS)

    Lasaygues, Philippe; Ouedraogo, Edgard; Lefebvre, Jean-Pierre; Gindre, Marcel; Talmant, Marilyne; Laugier, Pascal

    2005-01-01

    The objective of this study is to make cross-sectional ultrasonic quantitative tomography of the diaphysis of long bones. Ultrasonic propagation in bones is affected by the severe mismatch between the acoustic properties of this biological solid and those of the surrounding soft medium, namely, the soft tissues in vivo or water in vitro. Bone imaging is then a nonlinear inverse-scattering problem. In this paper, we showed that in vitro quantitative images of sound velocities in a human femur cross section could be reconstructed by combining ultrasonic reflection tomography (URT), which provides images of the macroscopic structure of the bone, and ultrasonic transmission tomography (UTT), which provides quantitative images of the sound velocity. For the shape, we developed an image-processing tool to extract the external and internal boundaries and cortical thickness measurements. For velocity mapping, we used a wavelet analysis tool adapted to ultrasound, which allowed us to detect precisely the time of flight from the transmitted signals. A brief review of the ultrasonic tomography that we developed using correction algorithms of the wavepaths and compensation procedures are presented. Also shown are the first results of our analyses on models and specimens of long bone using our new iterative quantitative protocol

  6. Quantitative cone beam X-ray luminescence tomography/X-ray computed tomography imaging

    International Nuclear Information System (INIS)

    Chen, Dongmei; Zhu, Shouping; Chen, Xueli; Chao, Tiantian; Cao, Xu; Zhao, Fengjun; Huang, Liyu; Liang, Jimin

    2014-01-01

    X-ray luminescence tomography (XLT) is an imaging technology based on X-ray-excitable materials. The main purpose of this paper is to obtain quantitative luminescence concentration using the structural information of the X-ray computed tomography (XCT) in the hybrid cone beam XLT/XCT system. A multi-wavelength luminescence cone beam XLT method with the structural a priori information is presented to relieve the severe ill-posedness problem in the cone beam XLT. The nanophosphors and phantom experiments were undertaken to access the linear relationship of the system response. Then, an in vivo mouse experiment was conducted. The in vivo experimental results show that the recovered concentration error as low as 6.67% with the location error of 0.85 mm can be achieved. The results demonstrate that the proposed method can accurately recover the nanophosphor inclusion and realize the quantitative imaging

  7. Multi-source quantitative photoacoustic tomography in a diffusive regime

    International Nuclear Information System (INIS)

    Bal, Guillaume; Ren, Kui

    2011-01-01

    Photoacoustic tomography (PAT) is a novel hybrid medical imaging technique that aims to combine the large contrast of optical coefficients with the high-resolution capabilities of ultrasound. We assume that the first step of PAT, namely the reconstruction of a map of absorbed radiation from ultrasound boundary measurement, has been done. We focus on quantitative photoacoustic tomography, which aims at quantitatively reconstructing the optical coefficients from knowledge of the absorbed radiation map. We present a non-iterative procedure to reconstruct such optical coefficients, namely the diffusion and absorption coefficients, and the Grüneisen coefficient when the propagation of radiation is modeled by a second-order elliptic equation. We show that PAT measurements allow us to uniquely reconstruct only two out of the above three coefficients, even when data are collected using an arbitrary number of radiation illuminations. We present uniqueness and stability results for the reconstructions of two such parameters and demonstrate the accuracy of the reconstruction algorithm with numerical reconstructions from two-dimensional synthetic data

  8. On multi-spectral quantitative photoacoustic tomography in diffusive regime

    International Nuclear Information System (INIS)

    Bal, Guillaume; Ren, Kui

    2012-01-01

    The objective of quantitative photoacoustic tomography (qPAT) is to reconstruct the diffusion, absorption and Grüneisen thermodynamic coefficients of heterogeneous media from knowledge of the interior absorbed radiation. It has been shown in Bal and Ren (2011 Inverse Problems 27 075003), based on diffusion theory, that with data acquired at one given wavelength, all three coefficients cannot be reconstructed uniquely. In this work, we study the multi-spectral qPAT problem and show that when multiple wavelength data are available, all coefficients can be reconstructed simultaneously under minor prior assumptions. Moreover, the reconstructions are shown to be very stable. We present some numerical simulations that support the theoretical results. (paper)

  9. A novel dual energy method for enhanced quantitative computed tomography

    Science.gov (United States)

    Emami, A.; Ghadiri, H.; Rahmim, A.; Ay, M. R.

    2018-01-01

    Accurate assessment of bone mineral density (BMD) is critically important in clinical practice, and conveniently enabled via quantitative computed tomography (QCT). Meanwhile, dual-energy QCT (DEQCT) enables enhanced detection of small changes in BMD relative to single-energy QCT (SEQCT). In the present study, we aimed to investigate the accuracy of QCT methods, with particular emphasis on a new dual-energy approach, in comparison to single-energy and conventional dual-energy techniques. We used a sinogram-based analytical CT simulator to model the complete chain of CT data acquisitions, and assessed performance of SEQCT and different DEQCT techniques in quantification of BMD. We demonstrate a 120% reduction in error when using a proposed dual-energy Simultaneous Equation by Constrained Least-squares method, enabling more accurate bone mineral measurements.

  10. Quantitative analysis of cholesteatoma using high resolution computed tomography

    International Nuclear Information System (INIS)

    Kikuchi, Shigeru; Yamasoba, Tatsuya; Iinuma, Toshitaka.

    1992-01-01

    Seventy-three cases of adult cholesteatoma, including 52 cases of pars flaccida type cholesteatoma and 21 of pars tensa type cholesteatoma, were examined using high resolution computed tomography, in both axial (lateral semicircular canal plane) and coronal sections (cochlear, vestibular and antral plane). These cases were classified into two subtypes according to the presence of extension of cholesteatoma into the antrum. Sixty cases of chronic otitis media with central perforation (COM) were also examined as controls. Various locations of the middle ear cavity were measured in terms of size in comparison with pars flaccida type cholesteatoma, pars tensa type cholesteatoma and COM. The width of the attic was significantly larger in both pars flaccida type and pars tensa type cholesteatoma than in COM. With pars flaccida type cholesteatoma there was a significantly larger distance between the malleus and lateral wall of the attic than with COM. In contrast, the distance between the malleus and medial wall of the attic was significantly larger with pars tensa type cholesteatoma than with COM. With cholesteatoma extending into the antrum, regardless of the type of cholesteatoma, there were significantly larger distances than with COM at the following sites: the width and height of the aditus ad antrum, and the width, height and anterior-posterior diameter of the antrum. However, these distances were not significantly different between cholesteatoma without extension into the antrum and COM. The hitherto demonstrated qualitative impressions of bone destruction in cholesteatoma were quantitatively verified in detail using high resolution computed tomography. (author)

  11. A Bayesian approach to spectral quantitative photoacoustic tomography

    International Nuclear Information System (INIS)

    Pulkkinen, A; Kaipio, J P; Tarvainen, T; Cox, B T; Arridge, S R

    2014-01-01

    A Bayesian approach to the optical reconstruction problem associated with spectral quantitative photoacoustic tomography is presented. The approach is derived for commonly used spectral tissue models of optical absorption and scattering: the absorption is described as a weighted sum of absorption spectra of known chromophores (spatially dependent chromophore concentrations), while the scattering is described using Mie scattering theory, with the proportionality constant and spectral power law parameter both spatially-dependent. It is validated using two-dimensional test problems composed of three biologically relevant chromophores: fat, oxygenated blood and deoxygenated blood. Using this approach it is possible to estimate the Grüneisen parameter, the absolute chromophore concentrations, and the Mie scattering parameters associated with spectral photoacoustic tomography problems. In addition, the direct estimation of the spectral parameters is compared to estimates obtained by fitting the spectral parameters to estimates of absorption, scattering and Grüneisen parameter at the investigated wavelengths. It is shown with numerical examples that the direct estimation results in better accuracy of the estimated parameters. (papers)

  12. Special issues in quantitation of brain receptors and related markers by emission computed tomography

    International Nuclear Information System (INIS)

    Links, J.M.

    1998-01-01

    Emission computed tomography provides an opportunity to quantify neurotransmitter-neuro receptor systems in vivo. In order to do so, very high image quality and quantitative accuracy are required. Quantitation of receptor systems involves considerations of physical effects (such as finite spatial resolution, scatter, and attenuation), instrumentation design (such as spatial sampling), image processing (such as filtering), and data analysis (such as kinetic modeling). Appropriate application of these considerations can lead to useful results, but emerging approaches promise even greater levels of accuracy and precision

  13. Role of computed tomography in quantitative assessment of emphysema

    International Nuclear Information System (INIS)

    Choromańska, Agnieszka; Macura, Katarzyna J.

    2012-01-01

    Pulmonary emphysema, together with chronic bronchitis is a part of chronic obstructive pulmonary disease (COPD), which is one of the leading causes of death in the United States and worldwide. There are many methods to diagnose emphysema. Unfortunately many of them, for example pulmonary function tests (PFTs), clinical signs and conventional radiology are able to detect emphysema usually in its late stages when a great portion of lung parenchyma has been already destroyed by the disease. Computed tomography (CT) allows for early detection of emphysema. CT also makes it possible to quantify the total amount of emphysema in the lungs which is important in order to precisely estimate the severity of the disease. Those abilities of CT are important in monitoring the course of the disease and in attempts to prevent its further progression. In this review we discuss currently available methods for imaging emphysema with emphasis on the quantitative assessment of emphysema. To date, quantitative methods have not been widely used clinically, however, the initial results of several research studies regarding this subject are very encouraging

  14. Quantitative x-ray dark-field computed tomography

    International Nuclear Information System (INIS)

    Bech, M; Pfeiffer, F; Bunk, O; Donath, T; David, C; Feidenhans'l, R

    2010-01-01

    The basic principles of x-ray image formation in radiology have remained essentially unchanged since Roentgen first discovered x-rays over a hundred years ago. The conventional approach relies on x-ray attenuation as the sole source of contrast and draws exclusively on ray or geometrical optics to describe and interpret image formation. Phase-contrast or coherent scatter imaging techniques, which can be understood using wave optics rather than ray optics, offer ways to augment or complement the conventional approach by incorporating the wave-optical interaction of x-rays with the specimen. With a recently developed approach based on x-ray optical gratings, advanced phase-contrast and dark-field scatter imaging modalities are now in reach for routine medical imaging and non-destructive testing applications. To quantitatively assess the new potential of particularly the grating-based dark-field imaging modality, we here introduce a mathematical formalism together with a material-dependent parameter, the so-called linear diffusion coefficient and show that this description can yield quantitative dark-field computed tomography (QDFCT) images of experimental test phantoms.

  15. Emission tomography: quantitative aspects in metabolic and physiopathologic studies

    International Nuclear Information System (INIS)

    Yerouchalmi-Soussaline, F.

    1984-11-01

    This thesis presents instrumental and data processing studies developped in emission tomography in man, using gamma and positron emitting tracers. High contrast visualisation of volume distribution of tracers in the organs, kinetic studies and measurements of radioactive concentration or of other clinical parameters necessitate a detailed analysis of all physical factors limiting the accuracy of the measure; therefore, development of adapted imaging devices and data processing techniques, together with models describing correctly the phenomena under study are to be carried out. Thus, in single photon (gamma) emission tomography an image reconstruction strategy is elaborated, based on an analytical model for the ill-posed problem including the attenuation effect. In positron emission tomography, the time-of-flight information combined with the reconstruction technique is used in the design of a first prototype imaging device which performance is presented and evaluated in a clinical environment. Moreover, a priori or a posteriori techniques correcting for Compton diffusion events, limited statistics and limited resolutions, are proposed and discussed for the improvement of regional measurement accuracy, in metabolic and physiopathologic studies [fr

  16. Quantitative computed tomography measures of emphysema and airway wall thickness are related to respiratory symptoms

    DEFF Research Database (Denmark)

    Grydeland, Thomas B; Dirksen, Asger; Coxson, Harvey O

    2010-01-01

    There is limited knowledge about the relationship between respiratory symptoms and quantitative high-resolution computed tomography measures of emphysema and airway wall thickness.......There is limited knowledge about the relationship between respiratory symptoms and quantitative high-resolution computed tomography measures of emphysema and airway wall thickness....

  17. Assessment of spinal trabecular bone by quantitative computed tomography

    International Nuclear Information System (INIS)

    Soya, Toshio; Seto, Hikaru; Futatsuya, Ryusuke; Kamei, Tetsuya; Kakishita, Masao

    1987-01-01

    151 normal values of spinal trabecular bone mineral content (BMC) for 79 men and 72 women were studied by single energy quantitative computed tomography (QCT). The BMC value has a great relation to age. It has a maximum in the age of 20 years in men and in the age of 20 ∼ 30 years in women, and decreases gradually after these ages with a more rapid reduction in women (1.1 % per year in men and 1.6 % per year in women). In younger generation (under 50 years of age) the average value of the BMC is 180 mg/ml K 2 HPO 4 equivalent in men, 189 mg/ml in women, and in older generation, is 123 mg/ml and 112 mg/ml respectively. In the individual case, the fluctuation of inter-vertebrae (L1, L2 and L3) has large variation, therefore, to estimate one's BMC enoughly the measurement of at least three vertebrae should be done. There found no physical factor which attributes to the BMC value. It is suggested that the BMC are affected by age and sex. (author)

  18. Quantitative analysis of left ventricular strain using cardiac computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Buss, Sebastian J., E-mail: sebastian.buss@med.uni-heidelberg.de [Department of Cardiology, University of Heidelberg, 69120 Heidelberg (Germany); Schulz, Felix; Mereles, Derliz [Department of Cardiology, University of Heidelberg, 69120 Heidelberg (Germany); Hosch, Waldemar [Department of Diagnostic and Interventional Radiology, University of Heidelberg, 69120 Heidelberg (Germany); Galuschky, Christian; Schummers, Georg; Stapf, Daniel [TomTec Imaging Systems GmbH, Munich (Germany); Hofmann, Nina; Giannitsis, Evangelos; Hardt, Stefan E. [Department of Cardiology, University of Heidelberg, 69120 Heidelberg (Germany); Kauczor, Hans-Ulrich [Department of Diagnostic and Interventional Radiology, University of Heidelberg, 69120 Heidelberg (Germany); Katus, Hugo A.; Korosoglou, Grigorios [Department of Cardiology, University of Heidelberg, 69120 Heidelberg (Germany)

    2014-03-15

    Objectives: To investigate whether cardiac computed tomography (CCT) can determine left ventricular (LV) radial, circumferential and longitudinal myocardial deformation in comparison to two-dimensional echocardiography in patients with congestive heart failure. Background: Echocardiography allows for accurate assessment of strain with high temporal resolution. A reduced strain is associated with a poor prognosis in cardiomyopathies. However, strain imaging is limited in patients with poor echogenic windows, so that, in selected cases, tomographic imaging techniques may be preferable for the evaluation of myocardial deformation. Methods: Consecutive patients (n = 27) with congestive heart failure who underwent a clinically indicated ECG-gated contrast-enhanced 64-slice dual-source CCT for the evaluation of the cardiac veins prior to cardiac resynchronization therapy (CRT) were included. All patients underwent additional echocardiography. LV radial, circumferential and longitudinal strain and strain rates were analyzed in identical midventricular short axis, 4-, 2- and 3-chamber views for both modalities using the same prototype software algorithm (feature tracking). Time for analysis was assessed for both modalities. Results: Close correlations were observed for both techniques regarding global strain (r = 0.93, r = 0.87 and r = 0.84 for radial, circumferential and longitudinal strain, respectively, p < 0.001 for all). Similar trends were observed for regional radial, longitudinal and circumferential strain (r = 0.88, r = 0.84 and r = 0.94, respectively, p < 0.001 for all). The number of non-diagnostic myocardial segments was significantly higher with echocardiography than with CCT (9.6% versus 1.9%, p < 0.001). In addition, the required time for complete quantitative strain analysis was significantly shorter for CCT compared to echocardiography (877 ± 119 s per patient versus 1105 ± 258 s per patient, p < 0.001). Conclusion: Quantitative assessment of LV strain

  19. Semi-quantitative myocardial perfusion measured by computed tomography in patients with refractory angina

    DEFF Research Database (Denmark)

    Qayyum, Abbas Ali; Kühl, Jørgen Tobias; Kjaer, Andreas

    2017-01-01

    INTRODUCTION: Computed tomography (CT) is a novel method for assessment of myocardial perfusion and has not yet been compared to rubidium-82 positron emission tomography (PET). We aimed to compare CT measured semi-quantitative myocardial perfusion with absolute quantified myocardial perfusion usi...

  20. Myocardial perfusion with multi-detector computed tomography: quantitative evaluation

    International Nuclear Information System (INIS)

    Carrascosa, Patricia M.; Vallejos, J.; Capunay, Carlos M.; Deviggiano, A.; Carrascosa, Jorge M.

    2007-01-01

    The objective of this work is to evaluate the skill of multidetector computer tomography, to quantify the different patterns of intensification during the evaluation of the myocardial perfusion. 45 patients were studied with suspicion of cardiovascular disease. Multi-detector computed tomography was utilized on patients at rest and in effort with pharmacological stress, after the administration of dipyridamole. Also they were evaluated using nuclear medicine [es

  1. Emission tomography with positrons principle, physical performances of a ring detector and quantitative possibilities

    International Nuclear Information System (INIS)

    Soussaline, F.; Plummer, D.; Todd Pokropek, A.E.; Loc'h, C.; Comar, D.

    1979-01-01

    Satisfactory qualitative and quantitative data in positron emission tomography requires the use of a well adapted tomographic system. A number of parameters have been identified which can be considered as the critical characteristics for evaluation and intercomparison of such systems. Using these the choice of a single slice ring positron camera could be justified by its physical performance, which is presented and discussed. Series of physical and mathematical simulations allow an appropriate knowledge of such a system, which has been in use for more than a year in a clinical environment. These studies aid to the interpretation of very interesting physiopathologic studies. In principle, a positron tomographic system permits measurement of absolute quantitative concentration values, which are essential for precise metabolic studies. The main sources of error comprising the calibration of the system, the tail effects and the precision for attenuation correction are analysed. When taking in account these errors, a precision of the order of 10% should be obtainable [fr

  2. HAADF-STEM atom counting in atom probe tomography specimens: Towards quantitative correlative microscopy.

    Science.gov (United States)

    Lefebvre, W; Hernandez-Maldonado, D; Moyon, F; Cuvilly, F; Vaudolon, C; Shinde, D; Vurpillot, F

    2015-12-01

    The geometry of atom probe tomography tips strongly differs from standard scanning transmission electron microscopy foils. Whereas the later are rather flat and thin (atom probe tomography specimens. Based on simulations (electron probe propagation and image simulations), the possibility to apply quantitative high angle annular dark field scanning transmission electron microscopy to of atom probe tomography specimens has been tested. The influence of electron probe convergence and the benefice of deconvolution of electron probe point spread function electron have been established. Atom counting in atom probe tomography specimens is for the first time reported in this present work. It is demonstrated that, based on single projections of high angle annular dark field imaging, significant quantitative information can be used as additional input for refining the data obtained by correlative analysis of the specimen in APT, therefore opening new perspectives in the field of atomic scale tomography. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Towards a quantitative interpretation of global seismic tomography

    NARCIS (Netherlands)

    Trampert, Jeannot; Hilst, R.D. van der

    2005-01-01

    We review the success of seismic tomography in delineating spatial variations in the propagation speed of seismic waves on length scales from several hundreds to many thousands of kilometers. In most interpretations these wave speed variations are thought to reflect variations in temperature.

  4. Quantitative imaging of magnetic nanoparticles by magneto-relaxometric tomography for biomedical applications; Quantitative Bildgebung magnetischer Nanopartikel mittels magnetrelaxometrischer Tomographie fuer biomedizinische Anwendungen

    Energy Technology Data Exchange (ETDEWEB)

    Liebl, Maik

    2016-11-18

    Current biomedical research focuses on the development of novel biomedical applications based on magnetic nanoparticles (MNPs), e.g. for local cancer treatment. These therapy approaches employ MNPs as remotely controlled drug carriers or local heat generators. Since location and quantity of MNPs determine drug enrichment and heat production, quantitative knowledge of the MNP distribution inside a body is essential for the development and success of these therapies. Magnetorelaxometry (MRX) is capable to provide such quantitative information based on the specific response of the MNPs after switching-off an applied magnetic field. Applying a uniform (homogeneous) magnetic field to a MNP distribution and measuring the MNP response by multiple sensors at different locations allows for spatially resolved MNP quantification. However, to reconstruct the MNP distribution from this spatially resolved MRX data, an ill posed inverse problem has to be solved. So far, the solution of this problem was stabilized incorporating a-priori knowledge in the forward model, e.g. by setting priors on the vertical position of the distribution using a 2D reconstruction grid or setting priors on the number and geometry of the MNP sources inside the body. MRX tomography represents a novel approach for quantitative 3D imaging of MNPs, where the inverse solution is stabilized by a series of MRX measurements. In MRX tomography, only parts of the MNP distribution are sequentially magnetized by the use of inhomogeneous magnetic fields. Each magnetizing is followed by detection of the response of the corresponding part of the distribution by multiple sensors. The 3D reconstruction of the MNP distribution is then accomplished by a common evaluation of the distinct MRX measurement series. In this thesis the first experimental setup for MRX tomography was developed for quantitative 3D imaging of biomedical MNP distributions. It is based on a multi-channel magnetizing unit which has been engineered to

  5. Quantitative imaging of tumor vasculature using multispectral optoacoustic tomography (MSOT)

    Science.gov (United States)

    Tomaszewski, Michal R.; Quiros-Gonzalez, Isabel; Joseph, James; Bohndiek, Sarah E.

    2017-03-01

    The ability to evaluate tumor oxygenation in the clinic could indicate prognosis and enable treatment monitoring, since oxygen deficient cancer cells are often more resistant to chemotherapy and radiotherapy. MultiSpectral Optoacoustic Tomography (MSOT) is a hybrid technique combining the high contrast of optical imaging with spatial resolution and penetration depth similar to ultrasound. We hypothesized that MSOT could reveal both tumor vascular density and function based on modulation of blood oxygenation. We performed MSOT on nude mice (n=8) bearing subcutaneous xenograft PC3 tumors using an inVision 256 (iThera Medical). The mice were maintained under inhalation anesthesia during imaging and respired oxygen content was modified from 21% to 100% and back. After imaging, Hoechst 33348 was injected to indicate vascular perfusion and permeability. Tumors were then extracted for histopathological analysis and fluorescence microscopy. The acquired data was analyzed to extract a bulk measurement of blood oxygenation (SO2MSOT) from the whole tumor using different approaches. The tumors were also automatically segmented into 5 regions to investigate the effect of depth on SO2MSOT. Baseline SO2MSOT values at 21% and 100% oxygen breathing showed no relationship with ex vivo measures of vascular density or function, while the change in SO2MSOT showed a strong negative correlation to Hoechst intensity (r=- 0.92, p=0.0016). Tumor voxels responding to oxygen challenge were spatially heterogeneous. We observed a significant drop in SO2 MSOT value with tumor depth following a switch of respiratory gas from air to oxygen (0.323+/-0.017 vs. 0.11+/-0.05, p=0.009 between 0 and 1.5mm depth), but no such effect for air breathing (0.265+/-0.013 vs. 0.19+/-0.04, p=0.14 between 0 and 1.5mm depth). Our results indicate that in subcutaneous prostate tumors, baseline SO2MSOT levels do not correlate to tumor vascular density or function while the magnitude of the response to oxygen

  6. Quantitation of the human basal ganglia with positron emission tomography

    International Nuclear Information System (INIS)

    Bendrien, B.; Dewey, S.L.; Schlyer, D.J.; Wolf, A.P.; Volkow, N.D.

    1990-01-01

    The accurate measurement of the concentration of a radioisotope in small structures with PET requires a correction for quantitation loss due to the partial volume effect and the effect of scattered radiation. To evaluate errors associated with measures in the human basal ganglia (BG) the authors have built a unilateral model of the BG that the authors have inserted in a 20 cm cylinder. The recovery coefficient (RC = measured activity/true activity) for the BG phantom has been measured on a CTI tomograph (model 931-08/12) with different background concentrations (contrast) and at different axial locations in the gantry. The BG was visualized on 4 or 5 slices depending on its position in the gantry and on the contrast used. The RC was 0.75 with no background (contrast equal to 1.0). Increasing the relative radioactivity 2.00 when the contrast was -0.7 (BG 2 ). This paper also demonstrates that the higher the contrast the more sensitive to axial positioning PET measurements in the BG are. These data provide the authors' with some information about the variability of PET measurements in small structure like the BG and the authors have proposed some strategies to improve the reproducibility

  7. Quantitation of the human basal ganglia with Positron Emission Tomography

    International Nuclear Information System (INIS)

    Bendriem, B.; Dewey, S.L.; Schlyer, D.J.; Wolf, A.P.; Volkow, N.D.

    1990-01-01

    The accurate measurement of the concentration of a radioisotope in small structures with PET requires a correction for quantitation loss due to the partial volume effect and the effect of scattered radiation. To evaluate errors associated with measures in the human basal ganglia (BG) we have built a unilateral model of the BG that we have inserted in a 20 cm cylinder. The recovery coefficient (RC = measured activity/true activity) for our BG phantom has been measured on a CTI tomograph (model 931-08/12) with different background concentrations (contrast) and at different axial locations in the gantry. The BG was visualized on 4 or 5 slices depending on its position in the gantry and on the contrast used. The RC was 0.75 with no background (contrast equal to 1.0). Increasing the relative radioactivity concentration in the background increased the RC from 0.75 to 2.00 when the contrast was -0.7 (BG 2 ). These results show that accurate RC correction depends not only on the volume of the structure but also on its contrast with its surroundings as well as on the selection of the ROI. They also demonstrate that the higher the contrast the more sensitive to axial positioning PET measurements in the BG are. These data provide us with some information about the variability of PET measurements in small structure like the BG and we have proposed some strategies to improve the reproducibility. 18 refs., 3 figs., 5 tabs

  8. Quantitative computed tomography applied to interstitial lung diseases.

    Science.gov (United States)

    Obert, Martin; Kampschulte, Marian; Limburg, Rebekka; Barańczuk, Stefan; Krombach, Gabriele A

    2018-03-01

    To evaluate a new image marker that retrieves information from computed tomography (CT) density histograms, with respect to classification properties between different lung parenchyma groups. Furthermore, to conduct a comparison of the new image marker with conventional markers. Density histograms from 220 different subjects (normal = 71; emphysema = 73; fibrotic = 76) were used to compare the conventionally applied emphysema index (EI), 15 th percentile value (PV), mean value (MV), variance (V), skewness (S), kurtosis (K), with a new histogram's functional shape (HFS) method. Multinomial logistic regression (MLR) analyses was performed to calculate predictions of different lung parenchyma group membership using the individual methods, as well as combinations thereof, as covariates. Overall correct assigned subjects (OCA), sensitivity (sens), specificity (spec), and Nagelkerke's pseudo R 2 (NR 2 ) effect size were estimated. NR 2 was used to set up a ranking list of the different methods. MLR indicates the highest classification power (OCA of 92%; sens 0.95; spec 0.89; NR 2 0.95) when all histogram analyses methods were applied together in the MLR. Highest classification power among individually applied methods was found using the HFS concept (OCA 86%; sens 0.93; spec 0.79; NR 2 0.80). Conventional methods achieved lower classification potential on their own: EI (OCA 69%; sens 0.95; spec 0.26; NR 2 0.52); PV (OCA 69%; sens 0.90; spec 0.37; NR 2 0.57); MV (OCA 65%; sens 0.71; spec 0.58; NR 2 0.61); V (OCA 66%; sens 0.72; spec 0.53; NR 2 0.66); S (OCA 65%; sens 0.88; spec 0.26; NR 2 0.55); and K (OCA 63%; sens 0.90; spec 0.16; NR 2 0.48). The HFS method, which was so far applied to a CT bone density curve analysis, is also a remarkable information extraction tool for lung density histograms. Presumably, being a principle mathematical approach, the HFS method can extract valuable health related information also from histograms from complete different areas

  9. A quantitative study of computer tomography images of the lumbar posterior elements

    International Nuclear Information System (INIS)

    Yamazaki, Ken

    1985-01-01

    The posterior elements of the lumbar spine in 125 vertebrae of 62 cases were studied quantitatively by computer tomography. The cases were classified into 4 groups: Group I (15 cases): Young (20 - 50 years old), normal by radiography and asymptomatic. Group II (15 cases): Aged (over 50 years old), spondylosis deformans by radiography and asymptomatic. Group III (15 cases): Aged spondylosis deformans by radiography and symptomatic. Group IV (17 cases): Aged, degenerative spondylolisthesis by radiography and symptomatic. The posterior recess consisting of the superior articular process (SAP) and the inferior articular process (IAP) (canal side) was measured by computer tomography. A relationship was found between the onset of symptoms and the effective area of the posterior recess (i.e. the area of the posterior recess without yellow ligament) for normal function (i.e. no block observed by myelography). In particular a bulging disc was observed near the entrance of the posterior recess by CT scan in the symptomatic groups. The factors which were related to the effective area were changes in the disc and yellow ligament, the entrance of the posterior recess, the prominence of IAP (canal side), and the superior articular facet angle. An index of the decrease in the effective area of the posterior recess calculated from four factors. Given that the length of the entrance of the posterior recess is the interfacetal distance (IFD), the depth of the posterior recess is the midsagittal distance (MSD) and the effective area is S, then RS = (IFD x MSD x 1/2-S)/(IFD x MSD x 1/2) x 100 (%) = [1 - (2 x S/(IFD x MSD))] x 100 (%) where RS = the narrowing ratio. The quantitative index of decrease in the effective area of the posterior recess (i.e. the narrowing ratio) may be useful in the diagnosis of degenerative lumbar spinal disease where the disc was bulging. (J.P.N.)

  10. A circular aperture array for ultrasonic tomography and quantitative NDE

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, S A

    1998-08-01

    The main topics of this thesis are ultrasonic tomography and ultrasonic determination of elastic stiffness constants. Both issues are based on a synthetic array with transducer elements distributed uniformly along a circular aperture, i.e., a circular aperture array. The issues are treated both theoretically and experimentally by broadband pulse techniques. Ultrasonic tomography, UCT, from a circular aperture is a relatively new imaging technique in Non-destructive Evaluation (NDE) to acquire cross sectional images in bulk materials. A filtered back-projection algorithm is used to reconstruct images in four different experiments and results of attenuation, velocity and reflection tomograms in Plexiglas of AlSi-alloy cylinders are presented. Two kinds of ultrasonic tomography are introduced: bistatic and monostatic imaging. Both techniques are verified experimentally by Plexiglas cylinders. Different reconstruction artifacts are discussed and theoretical resolution constraints are discussed for various configurations of the circular aperture array. The monostatic technique is used in volumetric imaging. In the experimental verification artificial and real discontinuities in a cylindrical AlSi-alloy are compared with similar discontinuities in a Plexiglas specimen. Finally, some limitations to UCT are discussed. The circular aperture array is used to determine five independent elastic stiffness constants of a unidirectional glass/PET (Poly Ethylene Teraphtalate) laminate. Energy flux propagation and attenuation of ultrasonic waves are considered and velocity surfaces are calculated for different planes of interest. Relations between elastic stiffness constants and engineering constants (i.e., Young`s moduli, shear moduli and Poisson`s ratios) are discussed for an orthotropic composite. Six micromechanical theories are reviewed, and expressions predicting the elastic engineering constants are evaluated. The micromechanical predicted elastic stiffness constants for the

  11. Tomography

    International Nuclear Information System (INIS)

    Allan, C.J.; Keller, N.A.; Lupton, L.R.; Taylor, T.; Tonner, P.D.

    1984-10-01

    Tomography is a non-intrusive imaging technique being developed at CRNL as an industrial tool for generating quantitative cross-sectional density maps of objects. Of most interest is tomography's ability to: distinguish features within complex geometries where other NDT techniques fail because of the complexity of the geometry; detect/locate small density changes/defects within objects, e.g. void fraction measurements within thick-walled vessels, shrink cavities in castings, etc.; provide quantitative data that can be used in analyses, e.g. of complex processes, or fracture mechanics; and provide objective quantitative data that can be used for (computer-based) quality assurance decisions, thereby reducing and in some cases eliminating the present subjectivity often encountered in NDT. The CRNL program is reviewed and examples are presented to illustrate the potential and the limitations of the technology

  12. Positron emission computerized tomography: a potential tool for in vivo quantitation of the distribution of radiopharmaceuticals

    International Nuclear Information System (INIS)

    Huebner, K.F.; King, P.; Gibbs, W.D.; Washburn, L.C.; Hayes, R.L.

    1981-01-01

    The principles and some of the difficulties in quantitative positron emission computerized tomography have been discussed. We have shown that randoms and scattered events are a major cause of noise and counting errors in positron emission computerized tomography. The noise has been identified as a convoluting process and a mathematical solution has been presented. Examples of phantom studies and in vivo measurements have demonstrated that the distribution of positron emitting radiopharmaceuticals can be quantitated with much improved accuracy using the deconvolution equation to remove undesired noise

  13. Two schemes for quantitative photoacoustic tomography based on Monte Carlo simulation

    International Nuclear Information System (INIS)

    Liu, Yubin; Yuan, Zhen; Jiang, Huabei

    2016-01-01

    Purpose: The aim of this study was to develop novel methods for photoacoustically determining the optical absorption coefficient of biological tissues using Monte Carlo (MC) simulation. Methods: In this study, the authors propose two quantitative photoacoustic tomography (PAT) methods for mapping the optical absorption coefficient. The reconstruction methods combine conventional PAT with MC simulation in a novel way to determine the optical absorption coefficient of biological tissues or organs. Specifically, the authors’ two schemes were theoretically and experimentally examined using simulations, tissue-mimicking phantoms, ex vivo, and in vivo tests. In particular, the authors explored these methods using several objects with different absorption contrasts embedded in turbid media and by using high-absorption media when the diffusion approximation was not effective at describing the photon transport. Results: The simulations and experimental tests showed that the reconstructions were quantitatively accurate in terms of the locations, sizes, and optical properties of the targets. The positions of the recovered targets were accessed by the property profiles, where the authors discovered that the off center error was less than 0.1 mm for the circular target. Meanwhile, the sizes and quantitative optical properties of the targets were quantified by estimating the full width half maximum of the optical absorption property. Interestingly, for the reconstructed sizes, the authors discovered that the errors ranged from 0 for relatively small-size targets to 26% for relatively large-size targets whereas for the recovered optical properties, the errors ranged from 0% to 12.5% for different cases. Conclusions: The authors found that their methods can quantitatively reconstruct absorbing objects of different sizes and optical contrasts even when the diffusion approximation is unable to accurately describe the photon propagation in biological tissues. In particular, their

  14. Fast quantitative MRI as a nonlinear tomography problem

    NARCIS (Netherlands)

    Sbrizzi, Alessandro; Heide, Oscar van der; Cloos, Martijn; van der Toorn, A; Hoogduin, Hans; Luijten, Peter R; van den Berg, Cornelis A T

    2018-01-01

    Quantitative Magnetic Resonance Imaging (MRI) is based on a two-steps approach: estimation of the magnetic moments distribution inside the body, followed by a voxel-by-voxel quantification of the human tissue properties. This splitting simplifies the computations but poses several constraints on the

  15. Quantitative evaluation of pontine atrophy using computer tomography

    Energy Technology Data Exchange (ETDEWEB)

    Chida, K.; Kamikura, I.; Takasu, T.; Goto, N.

    1989-03-01

    Pontine volume was measured and evaluated by computer tomography (CT) in 37 healthy adults and in 29 adult autopsied brains who did not have chronic neurologic diseases. The pons was cut serially into 5 mm slices in the autopsied brains. In the CT examinations both 5 mm and 2 mm slices were studied. Pontine areas in horizontal planes were measured using an image analyzer, then pontine volume was calculated by accumulation of the mean value of the areas and cranio-caudal length. Pontine volume was approximately 19 cm/sup 3/ and pontine atrophy could be defined as less than 12 cm/sup 3/ (i.e. the mean - 2 SD) in both methods, which heretofore have not been reported.

  16. Quantitative photo-acoustic tomography with partial data

    International Nuclear Information System (INIS)

    Chen, Jie; Yang, Yang

    2012-01-01

    Photo-acoustic tomography is a newly developed hybrid imaging modality that combines a high-resolution modality with a high-contrast modality. We analyze the reconstruction of diffusion and absorption parameters in an elliptic equation and extend an earlier result of Bal and Uhlmann (2010 Inverse Problems 26 085010) to the partial data case. We show that the reconstruction can be uniquely determined by the knowledge of four internal data based on well-chosen partial boundary conditions. Stability of this reconstruction is ensured if a convexity condition is satisfied. A similar stability result is obtained without this geometric constraint if 4n well chosen partial boundary conditions are available, where n is the spatial dimension. The set of well chosen boundary measurements is characterized by some complex geometric optics solutions vanishing on a part of the boundary. (paper)

  17. 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.

  18. Quantitation of cerebral blood flow using HMPAO tomography

    International Nuclear Information System (INIS)

    Bruyant, P.; Mallet, J.J.; Sau, J.; Teyssier, R.; Bonmartin, A.

    1997-01-01

    A method has been developed to quantitate regional cerebral blood flow (rCBF) using 99m Tc-HMPAO. It relies on the application of the bolus distribution principle. The rCBF is determined using compartmental analysis, by measuring the amount of tracer retained in the parenchyma and the input function. The values for blood: brain partition coefficient and for the conversion rate from the lipophilic to the hydrophilic form of the tracer are taken from the literature. Mean values for rCBF in eight patients are 41.1 ± 6.4 et 25.6 ± 5.8 mL.min -1 for the grey matter and for the white matter respectively (mean±standard deviation). This method allows to quantitate rCBF with one SPET scan and one venous blood sample. (authors)

  19. Utility of Quantitative Parameters from Single-Photon Emission Computed Tomography/Computed Tomography in Patients with Destructive Thyroiditis

    Science.gov (United States)

    Kim, Ji-Young; Kim, Ji Hyun; Moon, Jae Hoon; Kim, Kyoung Min; Oh, Tae Jung; Lee, Dong-Hwa; So, Young

    2018-01-01

    Objective Quantitative parameters from Tc-99m pertechnetate single-photon emission computed tomography/computed tomography (SPECT/CT) are emerging as novel diagnostic markers for functional thyroid diseases. We intended to assess the utility of SPECT/CT parameters in patients with destructive thyroiditis. Materials and Methods Thirty-five destructive thyroiditis patients (7 males and 28 females; mean age, 47.3 ± 13.0 years) and 20 euthyroid patients (6 males and 14 females; mean age, 45.0 ± 14.8 years) who underwent Tc-99m pertechnetate quantitative SPECT/CT were retrospectively enrolled. Quantitative parameters from the SPECT/CT (%uptake, standardized uptake value [SUV], thyroid volume, and functional thyroid mass [SUVmean × thyroid volume]) and thyroid hormone levels were investigated to assess correlations and predict the prognosis for destructive thyroiditis. The occurrence of hypothyroidism was the outcome for prognosis. Results All the SPECT/CT quantitative parameters were significantly lower in the 35 destructive thyroiditis patients compared to the 20 euthyroid patients using the same SPECT/CT scanner and protocol (p thyroid-stimulating hormone (TSH) significantly correlated with %uptake (p = 0.004), SUVmean (p thyroid mass (p thyroiditis patients, 16 progressed to hypothyroidism. On univariate and multivariate analyses, only T3 levels were associated with the later occurrence of hypothyroidism (p = 0.002, exp(β) = 1.022, 95% confidence interval: 1.008 – 1.035). Conclusion Novel quantitative SPECT/CT parameters could discriminate patients with destructive thyroiditis from euthyroid patients, suggesting the robustness of the quantitative SPECT/CT approach. However, disease progression of destructive thyroiditis could not be predicted using the parameters, as these only correlated with TSH, but not with T3, the sole predictor of the later occurrence of hypothyroidism. PMID:29713225

  20. Calibration Phantom for Quantitative Tomography Analysis of Biodistribution of Magnetic Nanoparticles

    Science.gov (United States)

    Rahn, Helen; Kettering, Melanie; Richter, Heike; Hilger, Ingrid; Trahms, Lutz; Odenbach, Stefan

    2010-12-01

    Ferrofluids are being investigated for cancer treatments such as magnetic drug targeting (MDT) and magnetic heating treatments with the aim of treating the cancer locally, since magnetic nanoparticles with attached drugs are concentrated within the target region. Thus, the side effects are considerably reduced. One of the crucial factors for the success of these therapies is the magnetic nanoparticle distribution. Microcomputed X-ray tomography (XμCT) has been introduced as adequate technique for non-destructive three-dimensional analysis of biological samples enriched with magnetic nanoparticles. The biological tissue specimens, in this case tumor bearing mice after intra-tumoral magnetic nanoparticle injection, have been analyzed by means of XμCT. Complementary measurements have been performed by magnetorelaxometry (MRX). This technique enables a sensitive quantification of magnetic nanoparticles down to few nanograms. For multi-phase samples, such as biological tissue enriched with magnetic nanoparticles the polychromasy and beam hardening artifacts occurring in XμCT with conventional X-ray tubes cause severe problems for quantitative density determination. This problem requires an appropriate calibration of the polychromatic tomography equipment enabling a semi-quantitative analysis of the data. For this purpose a phantom system has been implemented. These phantoms consist of a tissue substitute containing different amounts of magnetic nanoparticles. Since the attenuation of the beam also depends on the thickness i.e. the path length of the beam transmitting the object, the reference sample has been defined to a cone shape. Thus, with one phantom the information about the magnetic nanoparticle concentration as well as the attenuation in dependence of the path length can be determined. Two phantom systems will be presented, one based on agarose-gel and one based on soap.

  1. Quantitative X-ray dark-field and phase tomography using single directional speckle scanning technique

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hongchang, E-mail: hongchang.wang@diamond.ac.uk; Kashyap, Yogesh; Sawhney, Kawal [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom)

    2016-03-21

    X-ray dark-field contrast tomography can provide important supplementary information inside a sample to the conventional absorption tomography. Recently, the X-ray speckle based technique has been proposed to provide qualitative two-dimensional dark-field imaging with a simple experimental arrangement. In this letter, we deduce a relationship between the second moment of scattering angle distribution and cross-correlation degradation of speckle and establish a quantitative basis of X-ray dark-field tomography using single directional speckle scanning technique. In addition, the phase contrast images can be simultaneously retrieved permitting tomographic reconstruction, which yields enhanced contrast in weakly absorbing materials. Such complementary tomography technique can allow systematic investigation of complex samples containing both soft and hard materials.

  2. Quantitative phase tomography by using x-ray microscope with Foucault knife-edge scanning filter

    International Nuclear Information System (INIS)

    Watanabe, Norio; Tsuburaya, Yuji; Shimada, Akihiro; Aoki, Sadao

    2016-01-01

    Quantitative phase tomography was evaluated by using a differential phase microscope with a Foucault knife-edge scanning filter. A 3D x-ray phase image of polystyrene beads was obtained at 5.4 keV. The reconstructed refractive index was fairly good agreement with the Henke’s tabulated data

  3. Quantitative phase tomography by using x-ray microscope with Foucault knife-edge scanning filter

    Science.gov (United States)

    Watanabe, Norio; Tsuburaya, Yuji; Shimada, Akihiro; Aoki, Sadao

    2016-01-01

    Quantitative phase tomography was evaluated by using a differential phase microscope with a Foucault knife-edge scanning filter. A 3D x-ray phase image of polystyrene beads was obtained at 5.4 keV. The reconstructed refractive index was fairly good agreement with the Henke's tabulated data.

  4. Quantitative phase tomography by using x-ray microscope with Foucault knife-edge scanning filter

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Norio; Tsuburaya, Yuji; Shimada, Akihiro; Aoki, Sadao [Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8573 (Japan)

    2016-01-28

    Quantitative phase tomography was evaluated by using a differential phase microscope with a Foucault knife-edge scanning filter. A 3D x-ray phase image of polystyrene beads was obtained at 5.4 keV. The reconstructed refractive index was fairly good agreement with the Henke’s tabulated data.

  5. Quantitative computed tomography as a test of endurance for evaluation of bony plates

    International Nuclear Information System (INIS)

    Melo Filho, E.V.; Costa, L.A.V.S.; Oliveira, D.C.; Freitas, P.M.C.; Teixeira, M.W.; Costa, F.S.

    2012-01-01

    Quantitative computed tomography was used to determine the radiodensity of bony plates. The CT scans provided information regarding radiodensity of bony plates and allowed to verify the uniformity of bone mineral density in their scope. The proposed methodology should be considered as another tool for determining the resistance of these biomaterials. (author)

  6. Quantitative comparison of analysis methods for spectroscopic optical coherence tomography: reply to comment

    NARCIS (Netherlands)

    Bosschaart, Nienke; van Leeuwen, Ton; Aalders, Maurice C.G.; Faber, Dirk

    2014-01-01

    We reply to the comment by Kraszewski et al on “Quantitative comparison of analysis methods for spectroscopic optical coherence tomography.” We present additional simulations evaluating the proposed window function. We conclude that our simulations show good qualitative agreement with the results of

  7. Partial Volume Effects correction in emission tomography

    International Nuclear Information System (INIS)

    Le Pogam, Adrien

    2010-01-01

    Partial Volume Effects (PVE) designates the blur commonly found in nuclear medicine images and this PhD work is dedicated to their correction with the objectives of qualitative and quantitative improvement of such images. PVE arise from the limited spatial resolution of functional imaging with either Positron Emission Tomography (PET) or Single Photon Emission Computed Tomography (SPECT). They can be defined as a signal loss in tissues of size similar to the Full Width at Half Maximum (FWHM) of the PSF of the imaging device. In addition, PVE induce activity cross contamination between adjacent structures with different tracer uptakes. This can lead to under or over estimation of the real activity of such analyzed regions. Various methodologies currently exist to compensate or even correct for PVE and they may be classified depending on their place in the processing chain: either before, during or after the image reconstruction process, as well as their dependency on co-registered anatomical images with higher spatial resolution, for instance Computed Tomography (CT) or Magnetic Resonance Imaging (MRI). The voxel-based and post-reconstruction approach was chosen for this work to avoid regions of interest definition and dependency on proprietary reconstruction developed by each manufacturer, in order to improve the PVE correction. Two different contributions were carried out in this work: the first one is based on a multi-resolution methodology in the wavelet domain using the higher resolution details of a co-registered anatomical image associated to the functional dataset to correct. The second one is the improvement of iterative deconvolution based methodologies by using tools such as directional wavelets and curvelets extensions. These various developed approaches were applied and validated using synthetic, simulated and clinical images, for instance with neurology and oncology applications in mind. Finally, as currently available PET/CT scanners incorporate more

  8. Quantitative imaging of magnetic nanoparticles by magneto-relaxometric tomography for biomedical applications

    International Nuclear Information System (INIS)

    Liebl, Maik

    2016-01-01

    Current biomedical research focuses on the development of novel biomedical applications based on magnetic nanoparticles (MNPs), e.g. for local cancer treatment. These therapy approaches employ MNPs as remotely controlled drug carriers or local heat generators. Since location and quantity of MNPs determine drug enrichment and heat production, quantitative knowledge of the MNP distribution inside a body is essential for the development and success of these therapies. Magnetorelaxometry (MRX) is capable to provide such quantitative information based on the specific response of the MNPs after switching-off an applied magnetic field. Applying a uniform (homogeneous) magnetic field to a MNP distribution and measuring the MNP response by multiple sensors at different locations allows for spatially resolved MNP quantification. However, to reconstruct the MNP distribution from this spatially resolved MRX data, an ill posed inverse problem has to be solved. So far, the solution of this problem was stabilized incorporating a-priori knowledge in the forward model, e.g. by setting priors on the vertical position of the distribution using a 2D reconstruction grid or setting priors on the number and geometry of the MNP sources inside the body. MRX tomography represents a novel approach for quantitative 3D imaging of MNPs, where the inverse solution is stabilized by a series of MRX measurements. In MRX tomography, only parts of the MNP distribution are sequentially magnetized by the use of inhomogeneous magnetic fields. Each magnetizing is followed by detection of the response of the corresponding part of the distribution by multiple sensors. The 3D reconstruction of the MNP distribution is then accomplished by a common evaluation of the distinct MRX measurement series. In this thesis the first experimental setup for MRX tomography was developed for quantitative 3D imaging of biomedical MNP distributions. It is based on a multi-channel magnetizing unit which has been engineered to

  9. Comparison of low- and ultralow-dose computed tomography protocols for quantitative lung and airway assessment.

    Science.gov (United States)

    Hammond, Emily; Sloan, Chelsea; Newell, John D; Sieren, Jered P; Saylor, Melissa; Vidal, Craig; Hogue, Shayna; De Stefano, Frank; Sieren, Alexa; Hoffman, Eric A; Sieren, Jessica C

    2017-09-01

    Quantitative computed tomography (CT) measures are increasingly being developed and used to characterize lung disease. With recent advances in CT technologies, we sought to evaluate the quantitative accuracy of lung imaging at low- and ultralow-radiation doses with the use of iterative reconstruction (IR), tube current modulation (TCM), and spectral shaping. We investigated the effect of five independent CT protocols reconstructed with IR on quantitative airway measures and global lung measures using an in vivo large animal model as a human subject surrogate. A control protocol was chosen (NIH-SPIROMICS + TCM) and five independent protocols investigating TCM, low- and ultralow-radiation dose, and spectral shaping. For all scans, quantitative global parenchymal measurements (mean, median and standard deviation of the parenchymal HU, along with measures of emphysema) and global airway measurements (number of segmented airways and pi10) were generated. In addition, selected individual airway measurements (minor and major inner diameter, wall thickness, inner and outer area, inner and outer perimeter, wall area fraction, and inner equivalent circle diameter) were evaluated. Comparisons were made between control and target protocols using difference and repeatability measures. Estimated CT volume dose index (CTDIvol) across all protocols ranged from 7.32 mGy to 0.32 mGy. Low- and ultralow-dose protocols required more manual editing and resolved fewer airway branches; yet, comparable pi10 whole lung measures were observed across all protocols. Similar trends in acquired parenchymal and airway measurements were observed across all protocols, with increased measurement differences using the ultralow-dose protocols. However, for small airways (1.9 ± 0.2 mm) and medium airways (5.7 ± 0.4 mm), the measurement differences across all protocols were comparable to the control protocol repeatability across breath holds. Diameters, wall thickness, wall area fraction

  10. Quantitative single-photon emission tomography for cerebral flow and receptor distribution imaging

    International Nuclear Information System (INIS)

    Budinger, T.F.

    1985-01-01

    Recently there has been renewed interest in single-photon emission tomography for two major reasons. First, correction methods have been devised for attenuation compensation, nonuniform resolution, and scattered radiation. Second, new radiopharmaceuticals with 1-5% uptake in the brain provide adequate statistics for quantitative imaging of flow using properly designed single-photon tomographic instruments. The lack of commercially available instruments designed specifically to optimize sensitivity for a resolution finer than 15 mm full width at half maximum (FWHM) seems now to be the major deterrent to the widespread use of single-photon emission tomography. But it appears now that some development in this respect also might lead to a widespread renewed interest in single-photon tomography of the brain. Major activities of the past few years can be placed in three distinct categories of instrumentation and methodology

  11. Quantitative imaging using the Cleon emission tomography system

    International Nuclear Information System (INIS)

    Flower, M.A.; Parker, R.P.

    1980-01-01

    A revised method of correcting for attenuation has been investigated through experiments using discrete sources within a radioactive background. The effects of changing the source size, the source position relative to the central axis, and the ratio of the concentrations in the source and background have been studied. A comparison of the results obtained using old and new attenuation corrections show marked improvement. The measurement of radioactive concentration on the central axis had a typical systematic error of -14%, compared to -60% previously, but is generally dependent on source size, source position, and source and background concentrations. An allowance can be made for this error using experimental data

  12. Vertebral body trabecular density at the thoracolumbar junction using quantitative computed tomography

    International Nuclear Information System (INIS)

    Singer, K.P.; Breidahl, P.D.; Royal Perth Hospital

    1990-01-01

    Quantitative computed tomography was used to assess vertebral trabecular density in 26 post-mortem spines from individuals aged between 14 and 80 years. All vertebrae from T10 to L1 were scanned transversely near the mid-vertebral level with calculations of trabecular density in HUs averaged and referenced to a mineral equivalent phantom. An age-related decline in trabecular density was recorded (r=0.55, p<0.0001). Density measures from the anterior aspect of the vertebral body were significantly greater than from postero-lateral regions. From T10 to L1, there was a significant decrease in trabecular density, whereas density measures multiplied by vertebral body cross-sectional area were constant. Predictions of vertebral compressive strength using quantitative computed tomography may become more accurate by increasing the sampling area per scan and including vertebral body cross-sectional area as part of the radiologic assessment. (orig.)

  13. Quantitative assessment of left ventricular systolic wall thickening using multidetector computed tomography

    DEFF Research Database (Denmark)

    Kristensen, Thomas S; Kofoed, Klaus F; Møller, Daniel V

    2009-01-01

    BACKGROUND: Multidetector computed tomography (MDCT) of the heart provides both anatomical and functional information. The objective of this study was to evaluate the accuracy of quantitative assessment of left ventricular contractile function in relation to two-dimensional transthoracic echocard......BACKGROUND: Multidetector computed tomography (MDCT) of the heart provides both anatomical and functional information. The objective of this study was to evaluate the accuracy of quantitative assessment of left ventricular contractile function in relation to two-dimensional transthoracic...... echocardiography (TTE). MATERIALS AND METHODS: Sixty-four patients with known or suspected coronary artery disease underwent ECG-gated 64-slice MDCT and TTE. Regional left ventricular contractile function was measured by percent systolic wall thickening (SWT) in 16 myocardial segments using MDCT, and compared...

  14. Experimental investigation of bone mineral density in Thoroughbreds using quantitative computed tomography

    OpenAIRE

    YAMADA, Kazutaka; SATO, Fumio; HIGUCHI, Tohru; NISHIHARA, Kaori; KAYANO, Mitsunori; SASAKI, Naoki; NAMBO, Yasuo

    2015-01-01

    ABSTRACT Bone mineral density (BMD) is one of the indications of the strength and health. BMD measured by quantitative computed tomography (QCT) was compared with that measured by dual energy X-ray absorptiometry (DXA) and radiographic bone aluminum equivalence (RBAE). Limbs were removed from horses that had been euthanized for reasons not associated with this study. Sixteen limbs (left and right metacarpals and metatarsals) from 4 horses were used to compare BMD as measured by QCT with those...

  15. Experimental investigation of bone mineral density in Thoroughbreds using quantitative computed tomography

    OpenAIRE

    Yamada, Kazutaka; Sato, Fumio; Higuchi, Tohru; Nishihara, Kaori; Kayano, Mitsunori; Sasaki, Naoki; Nambo, Yasuo

    2015-01-01

    Bone mineral density (BMD) is one of the indications of the strength and health. BMD measured by quantitative computed tomography (QCT) was compared with that measured by dual energy X-ray absorptiometry (DXA) and radiographic bone aluminum equivalence (RBAE). Limbs were removed from horses that had been euthanized for reasons not associated with this study. Sixteen limbs (left and right metacarpals and metatarsals) from 4 horses were used to compare BMD as measured by QCT with those measured...

  16. Dual energy quantitative computed tomography (QCT). Precision of the mineral density measurements

    International Nuclear Information System (INIS)

    Braillon, P.; Bochu, M.

    1989-01-01

    The improvement that could be obtained in quantitative bone mineral measurements by dual energy computed tomography was tested in vitro. From the results of 15 mineral density measurements (in mg Ca/cm 3 , done on a precise lumbar spine phantom (Hologic) and referred to the values obtained on the same slices on a Siemens Osteo-CT phantom, the precision found was 0.8%, six times better than the precision calculated from the uncorrected measured values [fr

  17. Quantitative computed tomography: emphysema and airway wall thickness by sex, age and smoking

    DEFF Research Database (Denmark)

    Grydeland, T B; Dirksen, A; Coxson, H O

    2009-01-01

    We investigated how quantitative high-resolution computed tomography (HRCT) measures of emphysema and airway wall thickness (AWT) vary with sex, age and smoking history. We included 463 chronic obstructive pulmonary disease (COPD) cases and 431 controls. All included subjects were current or ex...... cases, respectively, and 0.488+/-0.028 and 0.463+/-0.025 in male and female controls, respectively. AWT decreased with increasing age in cases, and increased with the degree of current smoking in all subjects. We found significant differences in quantitative HRCT measures of emphysema and AWT between...

  18. Effect of long-term impact-loading on mass, size, and estimated strength of humerus and radius of female racquet-sports players: a peripheral quantitative computed tomography study between young and old starters and controls.

    Science.gov (United States)

    Kontulainen, Saija; Sievänen, Harri; Kannus, Pekka; Pasanen, Matti; Vuori, Ilkka

    2003-02-01

    Bone characteristics of the humeral shaft and distal radius were measured from 64 female tennis and squash players and their 27 age-, height-, and weight-matched controls with peripheral quantitative tomography (pQCT) and dual energy X-ray absorptiometry (DXA). The players were divided into two groups according to the starting age of their tennis or squash training (either before or after menarche) to examine the possible differences in the loading-induced changes in bone structure and volumetric density. The following pQCT variables were used: bone mineral content, total cross-sectional area of bone (TotA), cross-sectional area of the marrow cavity (CavA) and that of the cortical bone (CoA), cortical wall thickness (CWT), volumetric density of the cortical bone (CoD) and trabecular bone (TrD), and torsional bone strength index for the shaft (BSIt) and compressional bone strength index for the bone end (BSIc). These bone strength indices were compared with the DXA-derived areal bone mineral density (aBMD) to assess how well the latter represents the effect of mechanical loading on apparent bone strength. At the humeral shaft, the loaded arm's greater bone mineral content (an average 19% side-to-side difference in young starters and 9% in old starters), was caused by an enlarged cortex (CoA; side-to-side differences 20% and 9%, respectively). The loaded humerus seemed to have grown periosteally (the CavA did not differ between the sites), leading to 26% and 11% side-to-side BSIt differences in the young and old starters, respectively. CoD was equal between the arms (-1% difference in both player groups). The side-to-side differences in the young starters' bone mineral content, CoA, TotA, CWT, and BSIt were 8-22% higher than those of the controls and 8-14% higher than those of the old starters. Old starters' bone mineral content, CoA, and BSIt side-to-side differences were 6-7% greater than those in the controls. The DXA-derived side-to-side aBMD difference was 7

  19. Comparative analysis of bone mineral contents with dual-energy quantitative computed tomography

    International Nuclear Information System (INIS)

    Choi, T. J.; Yoon, S. M.; Kim, O. B.; Lee, S. M.; Suh, S. J.

    1997-01-01

    The Dual-Energy Quantitative Computed Tomography(DEQCT) was compared with bone equivalent K 2 HPO 4 standard solution and ash weight of animal cadaveric trabecular bone in the measurement of bone mineral contents(BMC). The attenuation coefficient of tissues highly depends on the radiation energy, density and effective atomic number of composition. The bone mineral content of DEQCT in this experiments was determined from empirical constants and mass attenuation coefficients of bone, fat and soft tissue equivalent solution in two photon spectra. In this experiments, the BMC of DEQCT with 80 and 120kV p X rays was compared to ash weight of animal trabecular bone. We obtained the mass attenuation coefficient of 0.2409, 0.5608 and 0.2206 in 80kV p , and 0.2046, 0.3273 and 0.1971 cm 2 /g in 120kV p X-ray spectra for water, bone and fat equivalent materials, respectively. The BMC with DEQCT was accomplished with empirical constants K 1 =0.3232, K 2 =0.2450 and mass attenuation coefficients has very closed to ash weight of animal trabecular bone. The BMC of empirical DEQCT and that of manufacturing DEQCT were correlated with ash weight as a correlation r=0.998 and r=0.996, respectively. The BMC of empirical DEQCT using the experimental mass attenuation coefficients and that of manufacture have showed very close to ash weight of animal trabecular bone. (author)

  20. Quantitative computed tomography derived structural geometric accuracy using custom built anthropometric phantom of the proximal femur

    International Nuclear Information System (INIS)

    Khoo, B.C.C.; Price, R.; Hicks, N.

    2011-01-01

    Full text: Material and structural properties influence bone strength. Structural strength may be determined through imaging methods, though currently there is no commercially available phantom to assess structural geometrical (SG) accuracy. This paper describes the design of an anthropometric SG phantom of the proximal femur and the performance testing on quantitative computed tomography (QCT) derived SG outcomes. Aims of study were to determine accuracy of QCT-derived SG outcomes and its effects from kYp. The phantom consists of three basic components; femoral head, a modular and interchangeable neck insert and shaft. The interchangeable neck modules were designed with different cortical thickness and shape. QCT scans were performed with Mindways QA (Mindways Software Inc., USA) phantom, then with anthropometric phantom in water bath together with Mindways calibration phantom. All QCT scans were done on Philips 64 MDCT (Philips Healthcare, USA). Three neck modules were selected and scanned. Each neck module was repeated scanned five times at 120 mAs, 0.67 mm slice thickness and 0.33 mm increment and at 80, 120 and 140 kYps. SG parameters analysed included bone mineral density(aBMD) and outer-diameter (OD).

  1. First experiences with model based iterative reconstructions influence on quantitative plaque volume and intensity measurements in coronary computed tomography angiography

    DEFF Research Database (Denmark)

    Precht, Helle; Kitslaar, Pieter H.; Broersen, Alexander

    2017-01-01

    Purpose: Investigate the influence of adaptive statistical iterative reconstruction (ASIR) and the model- based IR (Veo) reconstruction algorithm in coronary computed tomography angiography (CCTA) im- ages on quantitative measurements in coronary arteries for plaque volumes and intensities. Methods...

  2. Mineral compactness of vertebrae in Russian population in health according to quantitative computer-aided tomography

    International Nuclear Information System (INIS)

    Vlasova, I.S.; Sorokin, A.D.; Gorbatov, M.M.; Vozhagov, V.V.; Ternovoj, S.K.

    1998-01-01

    To create a reference database for residents of Central Russia and estimate the rate of calcium loss by bone tissue the mineral compactness of vertebral trabecular substance was studied by quantitative computer-aided tomography in 1061 subjects (610 females and 451 males aged 12-89 and 7-91 years, respectively) without somatic diseases and taking no drugs affecting osseous metabolism. Comparison of mineral bone density (MCB) regression curves in residents of Central Russia and of the values provided by producer firms shows differences in calcium content of vertebral trabecular substance, which can be due to specific ethnic features of different populations, lifestyle, and nutrition habits [ru

  3. Quantitative comparison of direct phase retrieval algorithms in in-line phase tomography

    International Nuclear Information System (INIS)

    Langer, Max; Cloetens, Peter; Guigay, Jean-Pierre; Peyrin, Francoise

    2008-01-01

    A well-known problem in x-ray microcomputed tomography is low sensitivity. Phase contrast imaging offers an increase of sensitivity of up to a factor of 10 3 in the hard x-ray region, which makes it possible to image soft tissue and small density variations. If a sufficiently coherent x-ray beam, such as that obtained from a third generation synchrotron, is used, phase contrast can be obtained by simply moving the detector downstream of the imaged object. This setup is known as in-line or propagation based phase contrast imaging. A quantitative relationship exists between the phase shift induced by the object and the recorded intensity and inversion of this relationship is called phase retrieval. Since the phase shift is proportional to projections through the three-dimensional refractive index distribution in the object, once the phase is retrieved, the refractive index can be reconstructed by using the phase as input to a tomographic reconstruction algorithm. A comparison between four phase retrieval algorithms is presented. The algorithms are based on the transport of intensity equation (TIE), transport of intensity equation for weak absorption, the contrast transfer function (CTF), and a mixed approach between the CTF and TIE, respectively. The compared methods all rely on linearization of the relationship between phase shift and recorded intensity to yield fast phase retrieval algorithms. The phase retrieval algorithms are compared using both simulated and experimental data, acquired at the European Synchrotron Radiation Facility third generation synchrotron light source. The algorithms are evaluated in terms of two different reconstruction error metrics. While being slightly less computationally effective, the mixed approach shows the best performance in terms of the chosen criteria.

  4. Respiratory gating in positron emission tomography: A quantitative comparison of different gating schemes

    International Nuclear Information System (INIS)

    Dawood, Mohammad; Buether, Florian; Lang, Norbert; Schober, Otmar; Schaefers, Klaus P

    2007-01-01

    Respiratory gating is used for reducing the effects of breathing motion in a wide range of applications from radiotherapy treatment to diagnostical imaging. Different methods are feasible for respiratory gating. In this study seven gating methods were developed and tested on positron emission tomography (PET) listmode data. The results of seven patient studies were compared quantitatively with respect to motion and noise. (1) Equal and (2) variable time-based gating methods use only the time information of the breathing cycle to define respiratory gates. (3) Equal and (4) variable amplitude-based gating approaches utilize the amplitude of the respiratory signal. (5) Cycle-based amplitude gating is a combination of time and amplitude-based techniques. A baseline correction was applied to methods (3) and (4) resulting in two new approaches: Baseline corrected (6) equal and (7) variable amplitude-based gating. Listmode PET data from seven patients were acquired together with a respiratory signal. Images were reconstructed applying the seven gating methods. Two parameters were used to quantify the results: Motion was measured as the displacement of the heart due to respiration and noise was defined as the standard deviation of pixel intensities in a background region. The amplitude-based approaches (3) and (4) were superior to the time-based methods (1) and (2). The improvement in capturing the motion was more than 30% (up to 130%) in all subjects. The variable time (2) and amplitude (4) methods had a more uniform noise distribution among all respiratory gates compared to equal time (1) and amplitude (3) methods. Baseline correction did not improve the results. Out of seven different respiratory gating approaches, the variable amplitude method (4) captures the respiratory motion best while keeping a constant noise level among all respiratory phases

  5. Quantitative computerized tomography for staging and follow up of patients with prostatic cancer

    International Nuclear Information System (INIS)

    Golimbu, C.; Golimbu, M.; Firooznia, H.; Rafii, M.; Morales, P.

    1987-01-01

    Prostate carcinoma has propensity to metastasize to skeleton, most frequently affecting the lumbar spine. The isotope bone scan and serum prostatic acid phosphatase (PAP) have been considered most reliable in documenting cancer spread. However, the former has been shown to have low specificity, and the latter was found to be increased in patients with localized disease or normal in patients with proven metastases. In a previous study of a group of patients at risk of having metastatic bone involvement, albeit not revealed by standard methods, the authors demonstrated the ability of quantitative computerized tomography (QCT) to depict early stages of bone metastases (Golimbu et. al., 1986). They also demonstrated its usefulness in assessing the response to treatment. The authors extended their study to further evaluate the accuracy of QCT in comparison with Tc99m bone scan and serum PAP for early detection of bone metastases and for quantitation of metastatic bone lesions response to therapy

  6. The quantitative assessment of peri-implant bone responses using histomorphometry and micro-computed tomography.

    NARCIS (Netherlands)

    Schouten, C.; Meijer, G.J.; Beucken, J.J.J.P van den; Spauwen, P.H.M.; Jansen, J.A.

    2009-01-01

    In the present study, the effects of implant design and surface properties on peri-implant bone response were evaluated with both conventional histomorphometry and micro-computed tomography (micro-CT), using two geometrically different dental implants (Screw type, St; Push-in, Pi) either or not

  7. Quantitative tomography of hydrogen precharged and uncharged Al-Zn-Mg-Cu alloy after tensile fracture

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, C., E-mail: joy_gupta71@yahoo.co.in [Department of Mechanical Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8150 (Japan); Toda, H.; Fujioka, T.; Kobayashi, M. [Department of Mechanical Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8150 (Japan); Hoshino, H. [Department of Mechanical Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8150 (Japan); Japan Synchrotron Radiation Institute, Sayo-Gun, Hyogo (Japan); Uesugi, K.; Takeuchi, A.; Suzuki, Y. [Japan Synchrotron Radiation Institute, Sayo-Gun, Hyogo (Japan)

    2016-07-18

    Quantitative tomography is carried out on datasets derived from tensile fracture sample of electrochemically precharged Al-Zn-Mg-Cu alloy in the underaged condition and its uncharged counterpart. It is shown that precharging which induces a transition of tensile fracture mode from ductile to brittle, results in a significant increase in micro-damage content in the regions near the fracture surfaces. Using quantitative tomography analysis based on spatial mapping of morphologically segmented micro-damage content of the datasets it is found that the precharged sample contains an inhomogenous distribution of micro-pores near grain boundaries. It is also shown that the spatial architecture of micro-pores in the dataset is not influenced by the plastic zone of the intergranular cracks lying along the grain boundaries. Contrastingly the micro-pores in the tomographic dataset of the uncharged sample are shown to be present near intermetallic particles. It is therefore rationalized that the spatial architecture of micro-pores in the datasets from uncharged sample originate from particle cracking during ductile fracture, and from the tendency for damage enhancement by the synergism of hydrogen exposure near grain boundaries and localization of deformation in the precharged sample dataset.

  8. Ex vivo characterization of pathologic fluids with quantitative phase-contrast computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Richter, Vivien, E-mail: vivien.richter@med.uni-tuebingen.de [Department of Diagnostic and Interventional Radiology, Eberhard Karls Universität Tübingen, Hoppe-Seyler-Weg 3, 72076 Tuebingen (Germany); Willner, Marian S., E-mail: marian.willner@ph.tum.de [Department of Physics & Institute of Medical Engineering, Technische Universität München, James-Franck-Strasse 1, 85748 Garching (Germany); Henningsen, John, E-mail: john.henningsen@tum.de [Department of Physics & Institute of Medical Engineering, Technische Universität München, James-Franck-Strasse 1, 85748 Garching (Germany); Birnbacher, Lorenz, E-mail: lorenz.birnbacher@ph.tum.de [Department of Physics & Institute of Medical Engineering, Technische Universität München, James-Franck-Strasse 1, 85748 Garching (Germany); Marschner, Mathias, E-mail: mathias.marschner@ph.tum.de [Department of Physics & Institute of Medical Engineering, Technische Universität München, James-Franck-Strasse 1, 85748 Garching (Germany); Herzen, Julia, E-mail: julia.herzen@ph.tum.de [Department of Physics & Institute of Medical Engineering, Technische Universität München, James-Franck-Strasse 1, 85748 Garching (Germany); Kimm, Melanie A., E-mail: melanie.kimm@tum.de [Department of Diagnostic and Interventional Radiology, Technische Universität München, Ismaninger Str. 22, 81675 Munich (Germany); and others

    2017-01-15

    Purpose: X-ray phase-contrast imaging (PCI) provides additional information beyond absorption characteristics by detecting the phase shift of the X-ray beam passing through material. The grating-based system works with standard polychromatic X-ray sources, promising a possible clinical implementation. PCI has been shown to provide additional information in soft-tissue samples. The aim of this study was to determine if ex vivo quantitative phase-contrast computed tomography (PCCT) may differentiate between pathologic fluid collections. Materials and methods: PCCT was performed with the grating interferometry method. A protein serial dilution, human blood samples and 17 clinical samples of pathologic fluid retentions were imaged and correlated with clinical chemistry measurements. Conventional and phase-contrast tomography images were reconstructed. Phase-contrast Hounsfield Units (HUp) were used for quantitative analysis analogously to conventional HU. The imaging was analyzed using overall means, ROI values as well as whole-volume-histograms and vertical gradients. Contrast to noise ratios were calculated between different probes and between imaging methods. Results: HUp showed a very good linear correlation with protein concentration in vitro. In clinical samples, HUp correlated rather well with cell count and triglyceride content. PCI was better than absorption imaging at differentiating protein concentrations in the protein samples as well as at differentiating blood plasma from cellular components. PCI also allowed for differentiation of watery samples (such as lymphoceles) from pus. Conclusion: Phase-contrast computed tomography is a promising tool for the differentiation of pathologic fluids that appear homogenous with conventional attenuation imaging.

  9. Methodological aspects in quantitative translational neuroimaging in central nervous system diseases with Positron Emission Tomography

    International Nuclear Information System (INIS)

    Müllauer, J.

    2013-01-01

    Patients suffering from central nervous system (CNS) diseases crucially depend on a sufficient supply with CNS active drugs that help them to control and endure their illness. As the site of action of CNS drugs is in the brain, these substances need to pass the blood-brain barrier (BBB), a physiological barrier seperating the blood circulation and the brain. However, CNS drug treatment is often accompanied by pharmacoresistance (drug resistance). Multidrug transporters, such as permeable glycoprotein (Pgp) are responsible for a gradient dependent transport of substances over the BBB. Drug resistance is hypothesised as a result of overactivity of multidrug transporters at the BBB, with the result of insufficient and poor CNS drug levels in the brain. In the case of epilepsy in up to 20 - 40% of patients drug resistance is observed. The influence of Ppg overexpression on drug resistance in epilepsy was studied using positron emission tomography (PET), a novel non-invasive nuclear imaging method, together with radioligands that interact with Pgp. Radiolabeled Pgp-substrates ((R)-[11C]verapamil), and inhibitors ([11C]elacridar and [11C]tariquidar) were developed and used to study the influence of Pgp and other transporters at the BBB in a translational research approach; in animal models of epilepsy and in humans. The aim in translational PET research is a direct comparision of gathered animal and human data. Consequently diverse methodological challenges arise, that need to be addressed and observed in order to enable a translation between species. To achieve full quantification of the function and density of drug transporters at the BBB in both, humans and rodents, kinetic modeling (compartmental modeling) was applied to the PET pharmacokinetic data. Estimated modeling parameters were in succession used to estimate biological and physiological processes of Pgp at the BBB. Subsequently, nonlinear mixed effects modeling was deployed to increase the mechanistic

  10. Precision of quantitative computed tomography texture analysis using image filtering: A phantom study for scanner variability.

    Science.gov (United States)

    Yasaka, Koichiro; Akai, Hiroyuki; Mackin, Dennis; Court, Laurence; Moros, Eduardo; Ohtomo, Kuni; Kiryu, Shigeru

    2017-05-01

    Quantitative computed tomography (CT) texture analyses for images with and without filtration are gaining attention to capture the heterogeneity of tumors. The aim of this study was to investigate how quantitative texture parameters using image filtering vary among different computed tomography (CT) scanners using a phantom developed for radiomics studies.A phantom, consisting of 10 different cartridges with various textures, was scanned under 6 different scanning protocols using four CT scanners from four different vendors. CT texture analyses were performed for both unfiltered images and filtered images (using a Laplacian of Gaussian spatial band-pass filter) featuring fine, medium, and coarse textures. Forty-five regions of interest were placed for each cartridge (x) in a specific scan image set (y), and the average of the texture values (T(x,y)) was calculated. The interquartile range (IQR) of T(x,y) among the 6 scans was calculated for a specific cartridge (IQR(x)), while the IQR of T(x,y) among the 10 cartridges was calculated for a specific scan (IQR(y)), and the median IQR(y) was then calculated for the 6 scans (as the control IQR, IQRc). The median of their quotient (IQR(x)/IQRc) among the 10 cartridges was defined as the variability index (VI).The VI was relatively small for the mean in unfiltered images (0.011) and for standard deviation (0.020-0.044) and entropy (0.040-0.044) in filtered images. Skewness and kurtosis in filtered images featuring medium and coarse textures were relatively variable across different CT scanners, with VIs of 0.638-0.692 and 0.430-0.437, respectively.Various quantitative CT texture parameters are robust and variable among different scanners, and the behavior of these parameters should be taken into consideration.

  11. Automated quantitative coronary computed tomography correlates of myocardial ischaemia on gated myocardial perfusion SPECT

    International Nuclear Information System (INIS)

    Graaf, Michiel A. de; Boogers, Mark J.; Veltman, Caroline E.; El-Naggar, Heba M.; Bax, Jeroen J.; Delgado, Victoria; Broersen, Alexander; Kitslaar, Pieter H.; Dijkstra, Jouke; Kroft, Lucia J.; Younis, Imad Al; Reiber, Johan H.; Scholte, Arthur J.

    2013-01-01

    Automated software tools have permitted more comprehensive, robust and reproducible quantification of coronary stenosis, plaque burden and plaque location of coronary computed tomography angiography (CTA) data. The association between these quantitative CTA (QCT) parameters and the presence of myocardial ischaemia has not been explored. The aim of the present investigation was to evaluate the association between QCT parameters of coronary artery lesions and the presence of myocardial ischaemia on gated myocardial perfusion single-photon emission CT (SPECT). Included in the study were 40 patients (mean age 58.2 ± 10.9 years, 27 men) with known or suspected coronary artery disease (CAD) who had undergone multidetector row CTA and gated myocardial perfusion SPECT within 6 months. From the CTA datasets, vessel-based and lesion-based visual analyses were performed. Consecutively, lesion-based QCT was performed to assess plaque length, plaque burden, percentage lumen area stenosis and remodelling index. Subsequently, the presence of myocardial ischaemia was assessed using the summed difference score (SDS ≥2) on gated myocardial perfusion SPECT. Myocardial ischaemia was seen in 25 patients (62.5 %) in 37 vascular territories. Quantitatively assessed significant stenosis and quantitatively assessed lesion length were independently associated with myocardial ischaemia (OR 7.72, 95 % CI 2.41-24.7, p 2 = 20.7) and lesion length (χ 2 = 26.0) to the clinical variables and the visual assessment (χ 2 = 5.9) had incremental value in the association with myocardial ischaemia. Coronary lesion length and quantitatively assessed significant stenosis were independently associated with myocardial ischaemia. Both quantitative parameters have incremental value over baseline variables and visually assessed significant stenosis. Potentially, QCT can refine assessment of CAD, which may be of potential use for identification of patients with myocardial ischaemia. (orig.)

  12. Automated Quantitative Computed Tomography Versus Visual Computed Tomography Scoring in Idiopathic Pulmonary Fibrosis: Validation Against Pulmonary Function.

    Science.gov (United States)

    Jacob, Joseph; Bartholmai, Brian J; Rajagopalan, Srinivasan; Kokosi, Maria; Nair, Arjun; Karwoski, Ronald; Raghunath, Sushravya M; Walsh, Simon L F; Wells, Athol U; Hansell, David M

    2016-09-01

    The aim of the study was to determine whether a novel computed tomography (CT) postprocessing software technique (CALIPER) is superior to visual CT scoring as judged by functional correlations in idiopathic pulmonary fibrosis (IPF). A total of 283 consecutive patients with IPF had CT parenchymal patterns evaluated quantitatively with CALIPER and by visual scoring. These 2 techniques were evaluated against: forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), diffusing capacity for carbon monoxide (DLco), carbon monoxide transfer coefficient (Kco), and a composite physiological index (CPI), with regard to extent of interstitial lung disease (ILD), extent of emphysema, and pulmonary vascular abnormalities. CALIPER-derived estimates of ILD extent demonstrated stronger univariate correlations than visual scores for most pulmonary function tests (PFTs): (FEV1: CALIPER R=0.29, visual R=0.18; FVC: CALIPER R=0.41, visual R=0.27; DLco: CALIPER R=0.31, visual R=0.35; CPI: CALIPER R=0.48, visual R=0.44). Correlations between CT measures of emphysema extent and PFTs were weak and did not differ significantly between CALIPER and visual scoring. Intriguingly, the pulmonary vessel volume provided similar correlations to total ILD extent scored by CALIPER for FVC, DLco, and CPI (FVC: R=0.45; DLco: R=0.34; CPI: R=0.53). CALIPER was superior to visual scoring as validated by functional correlations with PFTs. The pulmonary vessel volume, a novel CALIPER CT parameter with no visual scoring equivalent, has the potential to be a CT feature in the assessment of patients with IPF and requires further exploration.

  13. The relationship between lung function impairment and quantitative computed tomography in chronic obstructive pulmonary disease

    Energy Technology Data Exchange (ETDEWEB)

    Mets, O.M. [Radiology, University Medical Center Utrecht (Netherlands); University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Murphy, K. [Image Sciences Institute, University Medical Center Utrecht (Netherlands); Zanen, P.; Lammers, J.W. [Pulmonology, University Medical Center Utrecht (Netherlands); Gietema, H.A.; Jong, P.A. de [Radiology, University Medical Center Utrecht (Netherlands); Ginneken, B. van [Image Sciences Institute, University Medical Center Utrecht (Netherlands); Radboud University Nijmegen Medical Centre, Diagnostic Image Analysis Group, Radiology, Nijmegen (Netherlands); Prokop, M. [Radiology, University Medical Center Utrecht (Netherlands); Radiology, Radboud University Nijmegen Medical Centre (Netherlands)

    2012-01-15

    To determine the relationship between lung function impairment and quantitative computed tomography (CT) measurements of air trapping and emphysema in a population of current and former heavy smokers with and without airflow limitation. In 248 subjects (50 normal smokers; 50 mild obstruction; 50 moderate obstruction; 50 severe obstruction; 48 very severe obstruction) CT emphysema and CT air trapping were quantified on paired inspiratory and end-expiratory CT examinations using several available quantification methods. CT measurements were related to lung function (FEV{sub 1}, FEV{sub 1}/FVC, RV/TLC, Kco) by univariate and multivariate linear regression analysis. Quantitative CT measurements of emphysema and air trapping were strongly correlated to airflow limitation (univariate r-squared up to 0.72, p < 0.001). In multivariate analysis, the combination of CT emphysema and CT air trapping explained 68-83% of the variability in airflow limitation in subjects covering the total range of airflow limitation (p < 0.001). The combination of quantitative CT air trapping and emphysema measurements is strongly associated with lung function impairment in current and former heavy smokers with a wide range of airflow limitation. (orig.)

  14. The relationship between lung function impairment and quantitative computed tomography in chronic obstructive pulmonary disease

    International Nuclear Information System (INIS)

    Mets, O.M.; Murphy, K.; Zanen, P.; Lammers, J.W.; Gietema, H.A.; Jong, P.A. de; Ginneken, B. van; Prokop, M.

    2012-01-01

    To determine the relationship between lung function impairment and quantitative computed tomography (CT) measurements of air trapping and emphysema in a population of current and former heavy smokers with and without airflow limitation. In 248 subjects (50 normal smokers; 50 mild obstruction; 50 moderate obstruction; 50 severe obstruction; 48 very severe obstruction) CT emphysema and CT air trapping were quantified on paired inspiratory and end-expiratory CT examinations using several available quantification methods. CT measurements were related to lung function (FEV 1 , FEV 1 /FVC, RV/TLC, Kco) by univariate and multivariate linear regression analysis. Quantitative CT measurements of emphysema and air trapping were strongly correlated to airflow limitation (univariate r-squared up to 0.72, p < 0.001). In multivariate analysis, the combination of CT emphysema and CT air trapping explained 68-83% of the variability in airflow limitation in subjects covering the total range of airflow limitation (p < 0.001). The combination of quantitative CT air trapping and emphysema measurements is strongly associated with lung function impairment in current and former heavy smokers with a wide range of airflow limitation. (orig.)

  15. Experimental investigation of bone mineral density in Thoroughbreds using quantitative computed tomography

    Science.gov (United States)

    YAMADA, Kazutaka; SATO, Fumio; HIGUCHI, Tohru; NISHIHARA, Kaori; KAYANO, Mitsunori; SASAKI, Naoki; NAMBO, Yasuo

    2015-01-01

    ABSTRACT Bone mineral density (BMD) is one of the indications of the strength and health. BMD measured by quantitative computed tomography (QCT) was compared with that measured by dual energy X-ray absorptiometry (DXA) and radiographic bone aluminum equivalence (RBAE). Limbs were removed from horses that had been euthanized for reasons not associated with this study. Sixteen limbs (left and right metacarpals and metatarsals) from 4 horses were used to compare BMD as measured by QCT with those measured by DXA and RBAE. There was a strong correlation between BMD values measured by QCT and those measured by DXA (R2=0.85); correlation was also observed between values obtained by QCT and those obtained by RBAE (R2=0.61). To investigate changes in BMD with age, 37 right metacarpal bones, including 7 from horses euthanized because of fracture were examined by QCT. The BMD value of samples from horses dramatically increased until 2 years of age and then plateaued, a pattern similar to the growth curve. The BMD values of bone samples from horses euthanized because of fracture were within the population range, and samples of morbid fracture were not included. The relationship between BMD and age provides a reference for further quantitative studies of bone development and remodeling. Quantitative measurement of BMD using QCT may have great potential for the evaluation of bone biology for breeding and rearing management. PMID:26435681

  16. Changes in bone structure of Corriedale sheep with inherited rickets: a peripheral quantitative computed tomography assessment.

    Science.gov (United States)

    Dittmer, Keren E; Firth, Elwyn C; Thompson, Keith G; Marshall, Jonathan C; Blair, Hugh T

    2011-03-01

    An inherited skeletal disease with gross and microscopic features of rickets has been diagnosed in Corriedale sheep in New Zealand. The aim of this study was to quantify the changes present in tibia from sheep with inherited rickets using peripheral quantitative computed tomography. In affected sheep, scans in the proximal tibia, where metaphysis becomes diaphysis, showed significantly greater trabecular bone mineral content (BMC) and bone mineral density (BMD). The sheep with inherited rickets had significantly greater BMC and bone area in the mid-diaphysis of the proximal tibia compared to control sheep. However, BMD in the mid-diaphysis was significantly less in affected sheep than in controls, due to the greater cortical area and lower voxel density values in affected sheep. From this it was concluded that the increased strain on under-mineralised bone in sheep with inherited rickets led to increased bone mass in an attempt to improve bone strength. Copyright © 2010 Elsevier Ltd. All rights reserved.

  17. Single- versus dual-energy quantitative computed tomography for spinal densitometry in patients with rheumatoid arthritis

    International Nuclear Information System (INIS)

    Laan, R.F.J.M.; Erning, L.J.Th.O. van; Lemmens, J.A.M.; Putte, L.B.A. van de; Ruijs, S.H.J.; Riel, P.L.C.M. van

    1992-01-01

    Lumbar bone mineral density was measured by both single- and dual-energy quantitative computed tomography in 109 patients with rheumatoid arthritis. The results were corrected for the age-related increase in vertebral fat content by converting them to percentages of expected densities, using sex and energy-level specific regression equations obtained in a normal reference population. The percentages of expected density are approximately 10% lower in the single- than in the dual-energy mode, both in the patients with and without prednisone therapy. This difference is statistically highly significant, and is positively correlated with the duration of the disease and with the degree of radiological joint destruction. The data suggest that the vertebral fat content may be increased in patients with rheumatoid arthritis, as a consequence of disease-dependent mechanisms. (Author)

  18. Clinical application of quantitative computed tomography in osteogenesis imperfecta-suspected cat.

    Science.gov (United States)

    Won, Sungjun; Chung, Woo-Jo; Yoon, Junghee

    2017-09-30

    One-year-old male Persian cat presented with multiple fractures and no known traumatic history. Marked decrease of bone radiopacity and thin cortices of all long bones were identified on radiography. Tentative diagnosis was osteogenesis imperfecta, a congenital disorder characterized by fragile bone. To determine bone mineral density (BMD), quantitative computed tomography (QCT) was performed. The QCT results revealed a mean trabecular BMD of vertebral bodies of 149.9 ± 86.5 mg/cm 3 . After bisphosphonate therapy, BMD of the same site increased significantly (218.5 ± 117.1 mg/cm 3 , p < 0.05). QCT was a useful diagnostic tool to diagnose osteopenia and quantify response to medical treatment.

  19. Quantitative 3D imaging of yeast by hard X-ray tomography.

    Science.gov (United States)

    Zheng, Ting; Li, Wenjie; Guan, Yong; Song, Xiangxia; Xiong, Ying; Liu, Gang; Tian, Yangchao

    2012-05-01

    Full-field hard X-ray tomography could be used to obtain three-dimensional (3D) nanoscale structures of biological samples. The image of the fission yeast, Schizosaccharomyces pombe, was clearly visualized based on Zernike phase contrast imaging technique and heavy metal staining method at a spatial resolution better than 50 nm at the energy of 8 keV. The distributions and shapes of the organelles during the cell cycle were clearly visualized and two types of organelle were distinguished. The results for cells during various phases were compared and the ratios of organelle volume to cell volume can be analyzed quantitatively. It showed that the ratios remained constant between growth and division phase and increased strongly in stationary phase, following the shape and size of two types of organelles changes. Our results demonstrated that hard X-ray microscopy was a complementary method for imaging and revealing structural information for biological samples. Copyright © 2011 Wiley Periodicals, Inc.

  20. Quantitative assessment of cervical vertebral maturation using cone beam computed tomography in Korean girls.

    Science.gov (United States)

    Byun, Bo-Ram; Kim, Yong-Il; Yamaguchi, Tetsutaro; Maki, Koutaro; Son, Woo-Sung

    2015-01-01

    This study was aimed to examine the correlation between skeletal maturation status and parameters from the odontoid process/body of the second vertebra and the bodies of third and fourth cervical vertebrae and simultaneously build multiple regression models to be able to estimate skeletal maturation status in Korean girls. Hand-wrist radiographs and cone beam computed tomography (CBCT) images were obtained from 74 Korean girls (6-18 years of age). CBCT-generated cervical vertebral maturation (CVM) was used to demarcate the odontoid process and the body of the second cervical vertebra, based on the dentocentral synchondrosis. Correlation coefficient analysis and multiple linear regression analysis were used for each parameter of the cervical vertebrae (P cervical vertebral body and odontoid process, respectively, for the multiple regression models. This suggests that quantitative analysis might be used to estimate skeletal maturation status.

  1. Quantitative X-ray computed tomography peritoneography in malignant peritoneal mesothelioma patients receiving intraperitoneal chemotherapy.

    Science.gov (United States)

    Leinwand, Joshua C; Zhao, Binsheng; Guo, Xiaotao; Krishnamoorthy, Saravanan; Qi, Jing; Graziano, Joseph H; Slavkovic, Vesna N; Bates, Gleneara E; Lewin, Sharyn N; Allendorf, John D; Chabot, John A; Schwartz, Lawrence H; Taub, Robert N

    2013-12-01

    Intraperitoneal chemotherapy is used to treat peritoneal surface-spreading malignancies. We sought to determine whether volume and surface area of the intraperitoneal chemotherapy compartments are associated with overall survival and posttreatment glomerular filtration rate (GFR) in malignant peritoneal mesothelioma (MPM) patients. Thirty-eight MPM patients underwent X-ray computed tomography peritoneograms during outpatient intraperitoneal chemotherapy. We calculated volume and surface area of contrast-filled compartments by semiautomated computer algorithm. We tested whether these were associated with overall survival and posttreatment GFR. Decreased likelihood of mortality was associated with larger surface areas (p = 0.0201) and smaller contrast-filled compartment volumes (p = 0.0341), controlling for age, sex, histologic subtype, and presence of residual disease >0.5 cm postoperatively. Larger volumes were associated with higher posttreatment GFR, controlling for pretreatment GFR, body surface area, surface area, and the interaction between body surface area and volume (p = 0.0167). Computed tomography peritoneography is an appropriate modality to assess for maldistribution of intraperitoneal chemotherapy. In addition to identifying catheter failure and frank loculation, quantitative analysis of the contrast-filled compartment's surface area and volume may predict overall survival and cisplatin-induced nephrotoxicity. Prospective studies should be undertaken to confirm and extend these findings to other diseases, including advanced ovarian carcinoma.

  2. Swept source optical coherence tomography for quantitative and qualitative assessment of dental composite restorations

    Science.gov (United States)

    Sadr, Alireza; Shimada, Yasushi; Mayoral, Juan Ricardo; Hariri, Ilnaz; Bakhsh, Turki A.; Sumi, Yasunori; Tagami, Junji

    2011-03-01

    The aim of this work was to explore the utility of swept-source optical coherence tomography (SS-OCT) for quantitative evaluation of dental composite restorations. The system (Santec, Japan) with a center wavelength of around 1300 nm and axial resolution of 12 μm was used to record data during and after placement of light-cured composites. The Fresnel phenomenon at the interfacial defects resulted in brighter areas indicating gaps as small as a few micrometers. The gap extension at the interface was quantified and compared to the observation by confocal laser scanning microscope after trimming the specimen to the same cross-section. Also, video imaging of the composite during polymerization could provide information about real-time kinetics of contraction stress and resulting gaps, distinguishing them from those gaps resulting from poor adaptation of composite to the cavity prior to polymerization. Some samples were also subjected to a high resolution microfocus X-ray computed tomography (μCT) assessment; it was found that differentiation of smaller gaps from the radiolucent bonding layer was difficult with 3D μCT. Finally, a clinical imaging example using a newly developed dental SS-OCT system with an intra-oral scanning probe (Panasonic Healthcare, Japan) is presented. SS-OCT is a unique tool for clinical assessment and laboratory research on resin-based dental restorations. Supported by GCOE at TMDU and NCGG.

  3. Survival Prediction in Pancreatic Ductal Adenocarcinoma by Quantitative Computed Tomography Image Analysis.

    Science.gov (United States)

    Attiyeh, Marc A; Chakraborty, Jayasree; Doussot, Alexandre; Langdon-Embry, Liana; Mainarich, Shiana; Gönen, Mithat; Balachandran, Vinod P; D'Angelica, Michael I; DeMatteo, Ronald P; Jarnagin, William R; Kingham, T Peter; Allen, Peter J; Simpson, Amber L; Do, Richard K

    2018-04-01

    Pancreatic cancer is a highly lethal cancer with no established a priori markers of survival. Existing nomograms rely mainly on post-resection data and are of limited utility in directing surgical management. This study investigated the use of quantitative computed tomography (CT) features to preoperatively assess survival for pancreatic ductal adenocarcinoma (PDAC) patients. A prospectively maintained database identified consecutive chemotherapy-naive patients with CT angiography and resected PDAC between 2009 and 2012. Variation in CT enhancement patterns was extracted from the tumor region using texture analysis, a quantitative image analysis tool previously described in the literature. Two continuous survival models were constructed, with 70% of the data (training set) using Cox regression, first based only on preoperative serum cancer antigen (CA) 19-9 levels and image features (model A), and then on CA19-9, image features, and the Brennan score (composite pathology score; model B). The remaining 30% of the data (test set) were reserved for independent validation. A total of 161 patients were included in the analysis. Training and test sets contained 113 and 48 patients, respectively. Quantitative image features combined with CA19-9 achieved a c-index of 0.69 [integrated Brier score (IBS) 0.224] on the test data, while combining CA19-9, imaging, and the Brennan score achieved a c-index of 0.74 (IBS 0.200) on the test data. We present two continuous survival prediction models for resected PDAC patients. Quantitative analysis of CT texture features is associated with overall survival. Further work includes applying the model to an external dataset to increase the sample size for training and to determine its applicability.

  4. Quantitative 3D analysis of bone in hip osteoarthritis using clinical computed tomography.

    Science.gov (United States)

    Turmezei, Tom D; Treece, Graham M; Gee, Andrew H; Fotiadou, Anastasia F; Poole, Kenneth E S

    2016-07-01

    To assess the relationship between proximal femoral cortical bone thickness and radiological hip osteoarthritis using quantitative 3D analysis of clinical computed tomography (CT) data. Image analysis was performed on clinical CT imaging data from 203 female volunteers with a technique called cortical bone mapping (CBM). Colour thickness maps were created for each proximal femur. Statistical parametric mapping was performed to identify statistically significant differences in cortical bone thickness that corresponded with the severity of radiological hip osteoarthritis. Kellgren and Lawrence (K&L) grade, minimum joint space width (JSW) and a novel CT-based osteophyte score were also blindly assessed from the CT data. For each increase in K&L grade, cortical thickness increased by up to 25 % in distinct areas of the superolateral femoral head-neck junction and superior subchondral bone plate. For increasing severity of CT osteophytes, the increase in cortical thickness was more circumferential, involving a wider portion of the head-neck junction, with up to a 7 % increase in cortical thickness per increment in score. Results were not significant for minimum JSW. These findings indicate that quantitative 3D analysis of the proximal femur can identify changes in cortical bone thickness relevant to structural hip osteoarthritis. • CT is being increasingly used to assess bony involvement in osteoarthritis • CBM provides accurate and reliable quantitative analysis of cortical bone thickness • Cortical bone is thicker at the superior femoral head-neck with worse osteoarthritis • Regions of increased thickness co-locate with impingement and osteophyte formation • Quantitative 3D bone analysis could enable clinical disease prediction and therapy development.

  5. Quantitative shear wave imaging optical coherence tomography for noncontact mechanical characterization of myocardium

    Science.gov (United States)

    Wang, Shang; Lopez, Andrew L.; Morikawa, Yuka; Tao, Ge; Li, Jiasong; Larina, Irina V.; Martin, James F.; Larin, Kirill V.

    2015-03-01

    Optical coherence elastography (OCE) is an emerging low-coherence imaging technique that provides noninvasive assessment of tissue biomechanics with high spatial resolution. Among various OCE methods, the capability of quantitative measurement of tissue elasticity is of great importance for tissue characterization and pathology detection across different samples. Here we report a quantitative OCE technique, termed quantitative shear wave imaging optical coherence tomography (Q-SWI-OCT), which enables noncontact measurement of tissue Young's modulus based on the ultra-fast imaging of the shear wave propagation inside the sample. A focused air-puff device is used to interrogate the tissue with a low-pressure short-duration air stream that stimulates a localized displacement with the scale at micron level. The propagation of this tissue deformation in the form of shear wave is captured by a phase-sensitive OCT system running with the scan of the M-mode imaging over the path of the wave propagation. The temporal characteristics of the shear wave is quantified based on the cross-correlation of the tissue deformation profiles at all the measurement locations, and linear regression is utilized to fit the data plotted in the domain of time delay versus wave propagation distance. The wave group velocity is thus calculated, which results in the quantitative measurement of the Young's modulus. As the feasibility demonstration, experiments are performed on tissuemimicking phantoms with different agar concentrations and the quantified elasticity values with Q-SWI-OCT agree well with the uniaxial compression tests. For functional characterization of myocardium with this OCE technique, we perform our pilot experiments on ex vivo mouse cardiac muscle tissues with two studies, including 1) elasticity difference of cardiac muscle under relaxation and contract conditions and 2) mechanical heterogeneity of the heart introduced by the muscle fiber orientation. Our results suggest the

  6. Automated quantitative coronary computed tomography correlates of myocardial ischaemia on gated myocardial perfusion SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Graaf, Michiel A. de; Boogers, Mark J.; Veltman, Caroline E. [Leiden University Medical Center, Department of Cardiology, Leiden (Netherlands); The Interuniversity Cardiology Institute of The Netherlands, Utrecht (Netherlands); El-Naggar, Heba M.; Bax, Jeroen J.; Delgado, Victoria [Leiden University Medical Center, Department of Cardiology, Leiden (Netherlands); Broersen, Alexander; Kitslaar, Pieter H.; Dijkstra, Jouke [Leiden University Medical Center, Department of Radiology, Division of Image Processing, Leiden (Netherlands); Kroft, Lucia J. [Leiden University Medical Center, Department of Radiology, Leiden (Netherlands); Younis, Imad Al [Leiden University Medical Center, Department of Nuclear Medicine, Leiden (Netherlands); Reiber, Johan H. [Leiden University Medical Center, Department of Radiology, Division of Image Processing, Leiden (Netherlands); Medis medical imaging systems B.V., Leiden (Netherlands); Scholte, Arthur J. [Leiden University Medical Center, Department of Cardiology, Leiden (Netherlands)

    2013-08-15

    Automated software tools have permitted more comprehensive, robust and reproducible quantification of coronary stenosis, plaque burden and plaque location of coronary computed tomography angiography (CTA) data. The association between these quantitative CTA (QCT) parameters and the presence of myocardial ischaemia has not been explored. The aim of the present investigation was to evaluate the association between QCT parameters of coronary artery lesions and the presence of myocardial ischaemia on gated myocardial perfusion single-photon emission CT (SPECT). Included in the study were 40 patients (mean age 58.2 {+-} 10.9 years, 27 men) with known or suspected coronary artery disease (CAD) who had undergone multidetector row CTA and gated myocardial perfusion SPECT within 6 months. From the CTA datasets, vessel-based and lesion-based visual analyses were performed. Consecutively, lesion-based QCT was performed to assess plaque length, plaque burden, percentage lumen area stenosis and remodelling index. Subsequently, the presence of myocardial ischaemia was assessed using the summed difference score (SDS {>=}2) on gated myocardial perfusion SPECT. Myocardial ischaemia was seen in 25 patients (62.5 %) in 37 vascular territories. Quantitatively assessed significant stenosis and quantitatively assessed lesion length were independently associated with myocardial ischaemia (OR 7.72, 95 % CI 2.41-24.7, p < 0.001, and OR 1.07, 95 % CI 1.00-1.45, p = 0.032, respectively) after correcting for clinical variables and visually assessed significant stenosis. The addition of quantitatively assessed significant stenosis ({chi} {sup 2} = 20.7) and lesion length ({chi} {sup 2} = 26.0) to the clinical variables and the visual assessment ({chi} {sup 2} = 5.9) had incremental value in the association with myocardial ischaemia. Coronary lesion length and quantitatively assessed significant stenosis were independently associated with myocardial ischaemia. Both quantitative parameters have

  7. Quantitative 3D analysis of bone in hip osteoarthritis using clinical computed tomography

    International Nuclear Information System (INIS)

    Turmezei, Tom D.; Treece, Graham M.; Gee, Andrew H.; Fotiadou, Anastasia F.; Poole, Kenneth E.S.

    2016-01-01

    To assess the relationship between proximal femoral cortical bone thickness and radiological hip osteoarthritis using quantitative 3D analysis of clinical computed tomography (CT) data. Image analysis was performed on clinical CT imaging data from 203 female volunteers with a technique called cortical bone mapping (CBM). Colour thickness maps were created for each proximal femur. Statistical parametric mapping was performed to identify statistically significant differences in cortical bone thickness that corresponded with the severity of radiological hip osteoarthritis. Kellgren and Lawrence (K and L) grade, minimum joint space width (JSW) and a novel CT-based osteophyte score were also blindly assessed from the CT data. For each increase in K and L grade, cortical thickness increased by up to 25 % in distinct areas of the superolateral femoral head-neck junction and superior subchondral bone plate. For increasing severity of CT osteophytes, the increase in cortical thickness was more circumferential, involving a wider portion of the head-neck junction, with up to a 7 % increase in cortical thickness per increment in score. Results were not significant for minimum JSW. These findings indicate that quantitative 3D analysis of the proximal femur can identify changes in cortical bone thickness relevant to structural hip osteoarthritis. (orig.)

  8. Electrical impedance tomography-based sensing skin for quantitative imaging of damage in concrete

    International Nuclear Information System (INIS)

    Hallaji, Milad; Pour-Ghaz, Mohammad; Seppänen, Aku

    2014-01-01

    This paper outlines the development of a large-area sensing skin for damage detection in concrete structures. The developed sensing skin consists of a thin layer of electrically conductive copper paint that is applied to the surface of the concrete. Cracking of the concrete substrate results in the rupture of the sensing skin, decreasing its electrical conductivity locally. The decrease in conductivity is detected with electrical impedance tomography (EIT) imaging. In previous works, electrically based sensing skins have provided only qualitative information on the damage on the substrate surface. In this paper, we study whether quantitative imaging of the damage is possible. We utilize application-specific models and computational methods in the image reconstruction, including a total variation (TV) prior model for the damage and an approximate correction of the modeling errors caused by the inhomogeneity of the painted sensing skin. The developed damage detection method is tested experimentally by applying the sensing skin to polymeric substrates and a reinforced concrete beam under four-point bending. In all test cases, the EIT-based sensing skin provides quantitative information on cracks and/or other damages on the substrate surface: featuring a very low conductivity in the damage locations, and a reliable indication of the lengths and shapes of the cracks. The results strongly support the applicability of the painted EIT-based sensing skin for damage detection in reinforced concrete elements and other substrates. (paper)

  9. A calibrated iterative reconstruction for quantitative photoacoustic tomography using multi-angle light-sheet illuminations

    Science.gov (United States)

    Wang, Yihan; Lu, Tong; Zhang, Songhe; Song, Shaoze; Wang, Bingyuan; Li, Jiao; Zhao, Huijuan; Gao, Feng

    2018-02-01

    Quantitative photoacoustic tomography (q-PAT) is a nontrivial technique can be used to reconstruct the absorption image with a high spatial resolution. Several attempts have been investigated by setting point sources or fixed-angle illuminations. However, in practical applications, these schemes normally suffer from low signal-to-noise ratio (SNR) or poor quantification especially for large-size domains, due to the limitation of the ANSI-safety incidence and incompleteness in the data acquisition. We herein present a q-PAT implementation that uses multi-angle light-sheet illuminations and a calibrated iterative multi-angle reconstruction. The approach can acquire more complete information on the intrinsic absorption and SNR-boosted photoacoustic signals at selected planes from the multi-angle wide-field excitations of light-sheet. Therefore, the sliced absorption maps over whole body can be recovered in a measurementflexible, noise-robust and computation-economic way. The proposed approach is validated by the phantom experiment, exhibiting promising performances in image fidelity and quantitative accuracy.

  10. Application of microcomputed tomography for quantitative analysis of dental root canal obturations

    Directory of Open Access Journals (Sweden)

    Anna Kierklo

    2014-03-01

    Full Text Available Introduction: The aim of the study was to apply microcomputed tomography to quantitative evaluation of voids and to test any specific location of voids in tooth’s root canal obturations. Materials and Methods: Twenty root canals were prepared and obturated with gutta-percha and Tubli-Seal sealer using the thermoplastic compaction method (System B + Obtura II. Roots were scanned and three-dimensional visualization was obtained. The volume and Feret’s diameter of I-voids (at the filling/dentine interface and S-voids (surrounded by filling material were measured.Results: The results revealed that none of the scanned root canal fillings were void-free. For I-voids, the volume fraction was significantly larger, but their number was lower (P = 0.0007, than for S-voids. Both types of voids occurred in characteristic regions (P < 0.001. I-voids occurred mainly in the apical third, while S-voids in the coronal third of the canal filling.Conclusions: Within the limitations of this study, our results indicate that microtomography, with proposed semi-automatic algorithm, is a useful tools for three-dimensional quantitative evaluation of dental root canal fillings. In canals filled with thermoplastic gutta-percha and Tubli-Seal, voids at the interface between the filling and canal dentine deserve special attention due to of their periapical location, which might promote apical microleakage. Further studies might help to elucidate the clinical relevance of these results.

  11. Quantitative performance characterization of three-dimensional noncontact fluorescence molecular tomography

    Science.gov (United States)

    Favicchio, Rosy; Psycharakis, Stylianos; Schönig, Kai; Bartsch, Dusan; Mamalaki, Clio; Papamatheakis, Joseph; Ripoll, Jorge; Zacharakis, Giannis

    2016-02-01

    Fluorescent proteins and dyes are routine tools for biological research to describe the behavior of genes, proteins, and cells, as well as more complex physiological dynamics such as vessel permeability and pharmacokinetics. The use of these probes in whole body in vivo imaging would allow extending the range and scope of current biomedical applications and would be of great interest. In order to comply with a wide variety of application demands, in vivo imaging platform requirements span from wide spectral coverage to precise quantification capabilities. Fluorescence molecular tomography (FMT) detects and reconstructs in three dimensions the distribution of a fluorophore in vivo. Noncontact FMT allows fast scanning of an excitation source and noninvasive measurement of emitted fluorescent light using a virtual array detector operating in free space. Here, a rigorous process is defined that fully characterizes the performance of a custom-built horizontal noncontact FMT setup. Dynamic range, sensitivity, and quantitative accuracy across the visible spectrum were evaluated using fluorophores with emissions between 520 and 660 nm. These results demonstrate that high-performance quantitative three-dimensional visible light FMT allowed the detection of challenging mesenteric lymph nodes in vivo and the comparison of spectrally distinct fluorescent reporters in cell culture.

  12. Emission tomography: quantitative aspects in metabolic and physio-pathologic studies

    International Nuclear Information System (INIS)

    Yerouchalmi-Soussaline, F.

    1984-01-01

    This thesis presents instrumental and data processing studies developed in emission tomography in man, using gamma and positron emitting tracers. High contrast visualisation of volume distribution of tracers in the organs, kinetic studies and measurements of radioactive concentration or of other clinical parameters necessitate a detailed analysis of all physical factors limiting the accuracy of the measure; therefore, development of adapted imaging devices and data processing techniques, together with models describing correctly the phenomena under study are to be carried out. Thus, in single photon (gamma) emission tomography an image reconstruction strategy is elaborated, based on an analytical model for the ill-posed problem including the attenuation effect. In positron emission tomography, the time-of-flight information combined with the reconstruction technique is used in the design of a first prototype imaging device which performance is presented and evaluated in a clinical environment. Moreover, a priori or a posteriori techniques correcting for Compton diffusion events, limited statistics and limited resolution, are proposed and discussed for the improvement of regional measurement accuracy, in metabolic and physio-pathologic studies. (author) [fr

  13. Computed-tomography-guided anatomic standardization for quantitative assessment of dopamine transporter SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Yokoyama, Kota [National Center of Neurology and Psychiatry, Department of Radiology, Tokyo (Japan); National Center of Neurology and Psychiatry, Integrative Brain Imaging Center, Tokyo (Japan); Imabayashi, Etsuko; Matsuda, Hiroshi [National Center of Neurology and Psychiatry, Integrative Brain Imaging Center, Tokyo (Japan); Sumida, Kaoru; Sone, Daichi; Kimura, Yukio; Sato, Noriko [National Center of Neurology and Psychiatry, Department of Radiology, Tokyo (Japan); Mukai, Youhei; Murata, Miho [National Center of Neurology and Psychiatry, Department of Neurology, Tokyo (Japan)

    2017-03-15

    For the quantitative assessment of dopamine transporter (DAT) using [{sup 123}I]FP-CIT single-photon emission computed tomography (SPECT) (DaTscan), anatomic standardization is preferable for achieving objective and user-independent quantification of striatal binding using a volume-of-interest (VOI) template. However, low accumulation of DAT in Parkinson's disease (PD) would lead to a deformation error when using a DaTscan-specific template without any structural information. To avoid this deformation error, we applied computed tomography (CT) data obtained using SPECT/CT equipment to anatomic standardization. We retrospectively analyzed DaTscan images of 130 patients with parkinsonian syndromes (PS), including 80 PD and 50 non-PD patients. First we segmented gray matter from CT images using statistical parametric mapping 12 (SPM12). These gray-matter images were then anatomically standardized using the diffeomorphic anatomical registration using exponentiated Lie algebra (DARTEL) algorithm. Next, DaTscan images were warped with the same parameters used in the CT anatomic standardization. The target striatal VOIs for decreased DAT in PD were generated from the SPM12 group comparison of 20 DaTscan images from each group. We applied these VOIs to DaTscan images of the remaining patients in both groups and calculated the specific binding ratios (SBRs) using nonspecific counts in a reference area. In terms of the differential diagnosis of PD and non-PD groups using SBR, we compared the present method with two other methods, DaTQUANT and DaTView, which have already been released as software programs for the quantitative assessment of DaTscan images. The SPM12 group comparison showed a significant DAT decrease in PD patients in the bilateral whole striatum. Of the three methods assessed, the present CT-guided method showed the greatest power for discriminating PD and non-PD groups, as it completely separated the two groups. CT-guided anatomic standardization using

  14. Bone densitometry in healthy cats by quantitative computed tomography; Densitometria ossea em gatos higidos por tomografia computadorizada quantitativa

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, D.C. [Universidade Federal do Parana - Curitiba, PR (Brazil); Costa, L.A.V.S.; Teixeira, M.W.; Costa, F.S. [Universidade Federal Rural de Pernambuco - Recife, PE (Brazil); Cardoso, M.J.L. [Universidade Estadual do Norte do Parana - Campus Luiz Meneghel - Bandeirantes, PR (Brazil)

    2012-06-15

    The radiodensity of the trabecular bone of the lumbar vertebrae in 16 healthy adult cats was studied using quantitative computed tomography (QCT). The average radiodensity of the trabecular bone of the second lumbar vertebra was 436.1 +- 42.1 Hounsfield units. However, there was a nonhomogeneous radiodensity distribution of the vertebral body. (author)

  15. In vivo quantitative assessment of myocardial structure, function, perfusion and viability using cardiac micro-computed tomography

    NARCIS (Netherlands)

    E.D. van Deel (Elza); Y. Ridwan (Yanto); van Vliet, J.N. (J. Nicole); Belenkov, S. (Sasha); J. Essers (Jeroen)

    2016-01-01

    textabstractThe use of Micro-Computed Tomography (MicroCT) for in vivo studies of small animals as models of human disease has risen tremendously due to the fact that MicroCT provides quantitative high-resolution three-dimensional (3D) anatomical data non-destructively and longitudinally. Most

  16. Quantitative computed tomography versus spirometry in predicting air leak duration after major lung resection for cancer.

    Science.gov (United States)

    Ueda, Kazuhiro; Kaneda, Yoshikazu; Sudo, Manabu; Mitsutaka, Jinbo; Li, Tao-Sheng; Suga, Kazuyoshi; Tanaka, Nobuyuki; Hamano, Kimikazu

    2005-11-01

    Emphysema is a well-known risk factor for developing air leak or persistent air leak after pulmonary resection. Although quantitative computed tomography (CT) and spirometry are used to diagnose emphysema, it remains controversial whether these tests are predictive of the duration of postoperative air leak. Sixty-two consecutive patients who were scheduled to undergo major lung resection for cancer were enrolled in this prospective study to define the best predictor of postoperative air leak duration. Preoperative factors analyzed included spirometric variables and area of emphysema (proportion of the low-attenuation area) that was quantified in a three-dimensional CT lung model. Chest tubes were removed the day after disappearance of the air leak, regardless of pleural drainage. Univariate and multivariate proportional hazards analyses were used to determine the influence of preoperative factors on chest tube time (air leak duration). By univariate analysis, site of resection (upper, lower), forced expiratory volume in 1 second, predicted postoperative forced expiratory volume in 1 second, and area of emphysema ( 10%) were significant predictors of air leak duration. By multivariate analysis, site of resection and area of emphysema were the best independent determinants of air leak duration. The results were similar for patients with a smoking history (n = 40), but neither forced expiratory volume in 1 second nor predicted postoperative forced expiratory volume in 1 second were predictive of air leak duration. Quantitative CT is superior to spirometry in predicting air leak duration after major lung resection for cancer. Quantitative CT may aid in the identification of patients, particularly among those with a smoking history, requiring additional preventive procedures against air leak.

  17. Improving the quantitative accuracy of optical-emission computed tomography by incorporating an attenuation correction: application to HIF1 imaging

    Science.gov (United States)

    Kim, E.; Bowsher, J.; Thomas, A. S.; Sakhalkar, H.; Dewhirst, M.; Oldham, M.

    2008-10-01

    Optical computed tomography (optical-CT) and optical-emission computed tomography (optical-ECT) are new techniques for imaging the 3D structure and function (including gene expression) of whole unsectioned tissue samples. This work presents a method of improving the quantitative accuracy of optical-ECT by correcting for the 'self'-attenuation of photons emitted within the sample. The correction is analogous to a method commonly applied in single-photon-emission computed tomography reconstruction. The performance of the correction method was investigated by application to a transparent cylindrical gelatin phantom, containing a known distribution of attenuation (a central ink-doped gelatine core) and a known distribution of fluorescing fibres. Attenuation corrected and uncorrected optical-ECT images were reconstructed on the phantom to enable an evaluation of the effectiveness of the correction. Significant attenuation artefacts were observed in the uncorrected images where the central fibre appeared ~24% less intense due to greater attenuation from the surrounding ink-doped gelatin. This artefact was almost completely removed in the attenuation-corrected image, where the central fibre was within ~4% of the others. The successful phantom test enabled application of attenuation correction to optical-ECT images of an unsectioned human breast xenograft tumour grown subcutaneously on the hind leg of a nude mouse. This tumour cell line had been genetically labelled (pre-implantation) with fluorescent reporter genes such that all viable tumour cells expressed constitutive red fluorescent protein and hypoxia-inducible factor 1 transcription-produced green fluorescent protein. In addition to the fluorescent reporter labelling of gene expression, the tumour microvasculature was labelled by a light-absorbing vasculature contrast agent delivered in vivo by tail-vein injection. Optical-CT transmission images yielded high-resolution 3D images of the absorbing contrast agent, and

  18. Improving the quantitative accuracy of optical-emission computed tomography by incorporating an attenuation correction: application to HIF1 imaging

    International Nuclear Information System (INIS)

    Kim, E; Bowsher, J; Thomas, A S; Sakhalkar, H; Dewhirst, M; Oldham, M

    2008-01-01

    Optical computed tomography (optical-CT) and optical-emission computed tomography (optical-ECT) are new techniques for imaging the 3D structure and function (including gene expression) of whole unsectioned tissue samples. This work presents a method of improving the quantitative accuracy of optical-ECT by correcting for the 'self'-attenuation of photons emitted within the sample. The correction is analogous to a method commonly applied in single-photon-emission computed tomography reconstruction. The performance of the correction method was investigated by application to a transparent cylindrical gelatin phantom, containing a known distribution of attenuation (a central ink-doped gelatine core) and a known distribution of fluorescing fibres. Attenuation corrected and uncorrected optical-ECT images were reconstructed on the phantom to enable an evaluation of the effectiveness of the correction. Significant attenuation artefacts were observed in the uncorrected images where the central fibre appeared ∼24% less intense due to greater attenuation from the surrounding ink-doped gelatin. This artefact was almost completely removed in the attenuation-corrected image, where the central fibre was within ∼4% of the others. The successful phantom test enabled application of attenuation correction to optical-ECT images of an unsectioned human breast xenograft tumour grown subcutaneously on the hind leg of a nude mouse. This tumour cell line had been genetically labelled (pre-implantation) with fluorescent reporter genes such that all viable tumour cells expressed constitutive red fluorescent protein and hypoxia-inducible factor 1 transcription-produced green fluorescent protein. In addition to the fluorescent reporter labelling of gene expression, the tumour microvasculature was labelled by a light-absorbing vasculature contrast agent delivered in vivo by tail-vein injection. Optical-CT transmission images yielded high-resolution 3D images of the absorbing contrast agent

  19. The Influence of Reconstruction Kernel on Bone Mineral and Strength Estimates Using Quantitative Computed Tomography and Finite Element Analysis.

    Science.gov (United States)

    Michalski, Andrew S; Edwards, W Brent; Boyd, Steven K

    2017-10-17

    Quantitative computed tomography has been posed as an alternative imaging modality to investigate osteoporosis. We examined the influence of computed tomography convolution back-projection reconstruction kernels on the analysis of bone quantity and estimated mechanical properties in the proximal femur. Eighteen computed tomography scans of the proximal femur were reconstructed using both a standard smoothing reconstruction kernel and a bone-sharpening reconstruction kernel. Following phantom-based density calibration, we calculated typical bone quantity outcomes of integral volumetric bone mineral density, bone volume, and bone mineral content. Additionally, we performed finite element analysis in a standard sideways fall on the hip loading configuration. Significant differences for all outcome measures, except integral bone volume, were observed between the 2 reconstruction kernels. Volumetric bone mineral density measured using images reconstructed by the standard kernel was significantly lower (6.7%, p kernel. Furthermore, the whole-bone stiffness and the failure load measured in images reconstructed by the standard kernel were significantly lower (16.5%, p kernel. These data suggest that for future quantitative computed tomography studies, a standardized reconstruction kernel will maximize reproducibility, independent of the use of a quantitative calibration phantom. Copyright © 2017 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

  20. Diversity of respiratory impedance based on quantitative computed tomography in patients with COPD.

    Science.gov (United States)

    Wada, Yosuke; Kitaguchi, Yoshiaki; Yasuo, Masanori; Ueno, Fumika; Kawakami, Satoshi; Fukushima, Kiyoyasu; Fujimoto, Keisaku; Hanaoka, Masayuki

    2018-01-01

    This study was conducted in order to investigate the diversity of respiratory physiology, including the respiratory impedance and reversibility of airway obstruction, based on quantitative computed tomography (CT) in patients with COPD. Medical records of 174 stable COPD patients were retrospectively reviewed to obtain the patients' clinical data, including the pulmonary function and imaging data. According to the software-based quantification of the degree of emphysema and airway wall thickness, the patients were classified into the "normal by CT" phenotype, the airway-dominant phenotype, the emphysema-dominant phenotype, and the mixed phenotype. The pulmonary function, including the respiratory impedance evaluated by using the forced oscillation technique (FOT) and the reversibility of airway obstruction in response to inhaled short-acting β 2 -agonists, was then compared among the four phenotypes. The respiratory system resistance at 5 and 20 Hz (R5 and R20) was significantly higher, and the respiratory system reactance at 5 Hz (X5) was significantly more negative in the airway-dominant and mixed phenotypes than in the other phenotypes. The within-breath changes of X5 (ΔX5) were significantly greater in the mixed phenotype than in the "normal by CT" and emphysema-dominant phenotypes. The FOT parameters (R5, R20, and X5) were significantly correlated with indices of the degree of airway wall thickness and significantly but weakly correlated with the reversibility of airway obstruction. There was no significant correlation between the FOT parameters (R5, R20, and X5) and the degree of emphysema. There is a diversity of respiratory physiology, including the respiratory impedance and reversibility of airway obstruction, based on quantitative CT in patients with COPD. The FOT measurements may reflect the degree of airway disease and aid in detecting airway remodeling in patients with COPD.

  1. Quantitative analysis of muscular wastings of lower limbs in Duchenne muscular dystrophy by computed tomography

    International Nuclear Information System (INIS)

    Horikawa, Hirosei; Konagaya, Masaaki; Takayanagi, Tetsuya; Otsuji, Hideaki

    1985-01-01

    We quantitatively evaluated the muscular wastings of lower extremities in Duchenne muscular dystrophy (DMD) by computed tomography (CT). The subjects were 21 cases of DMD (an ambulant case and 20 wheelchair-ridden cases, ages ranging from 10 to 21 years old) and 4 control males. The CT scan was carried out at the mid-level between lesser trochanter and medial condyle of femur and the largest diameter level of lower leg. The density and the cross-sectional area of each muscle were measured on the CT image. The average CT number of normal muscle was varying from 40 to 60, as well as that of fat was -115. Then we calculated CT index of each muscle denoted as follows: CT index = [average CT number of muscle-(-115)] X(cross-sectional area of each muscle). The measurements of muscle strength and serum CK level were performed and their relationships to CT index were examined. The results were achieved as follows: 1) Wheelchair-ridden cases with DMD showed severe decrease in the average CT number and the CT index of each muscle with normal controls. With progression, the average CT number and the CT index were reduced. But gracilis muscle and sartorius muscle were relatively spared in comparison with other muscles. 2) There was positive correlation between the CT index and the muscle strength in triceps surae muscle, hamstrings muslce and quardriceps femoris muscle. 3) The CT index of whole thigh muscles and that of whole lower leg muscles were highly correlated to serum CK level. These results suggest that the quantitative analysis of muscle CT is an useful measurement for assessement of muscular wastings in DMD. (author)

  2. Massively parallel data processing for quantitative total flow imaging with optical coherence microscopy and tomography

    Science.gov (United States)

    Sylwestrzak, Marcin; Szlag, Daniel; Marchand, Paul J.; Kumar, Ashwin S.; Lasser, Theo

    2017-08-01

    We present an application of massively parallel processing of quantitative flow measurements data acquired using spectral optical coherence microscopy (SOCM). The need for massive signal processing of these particular datasets has been a major hurdle for many applications based on SOCM. In view of this difficulty, we implemented and adapted quantitative total flow estimation algorithms on graphics processing units (GPU) and achieved a 150 fold reduction in processing time when compared to a former CPU implementation. As SOCM constitutes the microscopy counterpart to spectral optical coherence tomography (SOCT), the developed processing procedure can be applied to both imaging modalities. We present the developed DLL library integrated in MATLAB (with an example) and have included the source code for adaptations and future improvements. Catalogue identifier: AFBT_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AFBT_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU GPLv3 No. of lines in distributed program, including test data, etc.: 913552 No. of bytes in distributed program, including test data, etc.: 270876249 Distribution format: tar.gz Programming language: CUDA/C, MATLAB. Computer: Intel x64 CPU, GPU supporting CUDA technology. Operating system: 64-bit Windows 7 Professional. Has the code been vectorized or parallelized?: Yes, CPU code has been vectorized in MATLAB, CUDA code has been parallelized. RAM: Dependent on users parameters, typically between several gigabytes and several tens of gigabytes Classification: 6.5, 18. Nature of problem: Speed up of data processing in optical coherence microscopy Solution method: Utilization of GPU for massively parallel data processing Additional comments: Compiled DLL library with source code and documentation, example of utilization (MATLAB script with raw data) Running time: 1,8 s for one B-scan (150 × faster in comparison to the CPU

  3. SU-D-210-03: Limited-View Multi-Source Quantitative Photoacoustic Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Feng, J; Gao, H [Shanghai Jiao Tong University, Shanghai, Shanghai (China)

    2015-06-15

    Purpose: This work is to investigate a novel limited-view multi-source acquisition scheme for the direct and simultaneous reconstruction of optical coefficients in quantitative photoacoustic tomography (QPAT), which has potentially improved signal-to-noise ratio and reduced data acquisition time. Methods: Conventional QPAT is often considered in two steps: first to reconstruct the initial acoustic pressure from the full-view ultrasonic data after each optical illumination, and then to quantitatively reconstruct optical coefficients (e.g., absorption and scattering coefficients) from the initial acoustic pressure, using multi-source or multi-wavelength scheme.Based on a novel limited-view multi-source scheme here, We have to consider the direct reconstruction of optical coefficients from the ultrasonic data, since the initial acoustic pressure can no longer be reconstructed as an intermediate variable due to the incomplete acoustic data in the proposed limited-view scheme. In this work, based on a coupled photo-acoustic forward model combining diffusion approximation and wave equation, we develop a limited-memory Quasi-Newton method (LBFGS) for image reconstruction that utilizes the adjoint forward problem for fast computation of gradients. Furthermore, the tensor framelet sparsity is utilized to improve the image reconstruction which is solved by Alternative Direction Method of Multipliers (ADMM). Results: The simulation was performed on a modified Shepp-Logan phantom to validate the feasibility of the proposed limited-view scheme and its corresponding image reconstruction algorithms. Conclusion: A limited-view multi-source QPAT scheme is proposed, i.e., the partial-view acoustic data acquisition accompanying each optical illumination, and then the simultaneous rotations of both optical sources and ultrasonic detectors for next optical illumination. Moreover, LBFGS and ADMM algorithms are developed for the direct reconstruction of optical coefficients from the

  4. Multi-institutional Quantitative Evaluation and Clinical Validation of Smart Probabilistic Image Contouring Engine (SPICE) Autosegmentation of Target Structures and Normal Tissues on Computer Tomography Images in the Head and Neck, Thorax, Liver, and Male Pelvis Areas

    DEFF Research Database (Denmark)

    Zhu, Mingyao; Bzdusek, Karl; Brink, Carsten

    2013-01-01

    Clinical validation and quantitative evaluation of computed tomography (CT) image autosegmentation using Smart Probabilistic Image Contouring Engine (SPICE).......Clinical validation and quantitative evaluation of computed tomography (CT) image autosegmentation using Smart Probabilistic Image Contouring Engine (SPICE)....

  5. Quantitative evaluation of the disintegration of orally rapid disintegrating tablets by X-ray computed tomography.

    Science.gov (United States)

    Otsuka, Makoto; Yamanaka, Azusa; Uchino, Tomohiro; Otsuka, Kuniko; Sadamoto, Kiyomi; Ohshima, Hiroyuki

    2012-01-01

    To measure the rapid disintegration of Oral Disintegrating Tablets (ODT), a new test (XCT) was developed using X-ray computing tomography (X-ray CT). Placebo ODT, rapid disintegration candy (RDC) and Gaster®-D-Tablets (GAS) were used as model samples. All these ODTs were used to measure oral disintegration time (DT) in distilled water at 37±2°C by XCT. DTs were affected by the width of mesh screens, and degree to which the tablet holder vibrated from air bubbles. An in-vivo tablet disintegration test was performed for RDC using 11 volunteers. DT by the in-vivo method was significantly longer than that using the conventional tester. The experimental conditions for XCT such as the width of the mesh screen and degree of vibration were adjusted to be consistent with human DT values. Since DTs by the XCT method were almost the same as the human data, this method was able to quantitatively evaluate the rapid disintegration of ODT under the same conditions as inside the oral cavity. The DTs of four commercially available ODTs were comparatively evaluated by the XCT method, conventional tablet disintegration test and in-vivo method.

  6. Micro/nano-computed tomography technology for quantitative dynamic, multi-scale imaging of morphogenesis.

    Science.gov (United States)

    Gregg, Chelsea L; Recknagel, Andrew K; Butcher, Jonathan T

    2015-01-01

    Tissue morphogenesis and embryonic development are dynamic events challenging to quantify, especially considering the intricate events that happen simultaneously in different locations and time. Micro- and more recently nano-computed tomography (micro/nanoCT) has been used for the past 15 years to characterize large 3D fields of tortuous geometries at high spatial resolution. We and others have advanced micro/nanoCT imaging strategies for quantifying tissue- and organ-level fate changes throughout morphogenesis. Exogenous soft tissue contrast media enables visualization of vascular lumens and tissues via extravasation. Furthermore, the emergence of antigen-specific tissue contrast enables direct quantitative visualization of protein and mRNA expression. Micro-CT X-ray doses appear to be non-embryotoxic, enabling longitudinal imaging studies in live embryos. In this chapter we present established soft tissue contrast protocols for obtaining high-quality micro/nanoCT images and the image processing techniques useful for quantifying anatomical and physiological information from the data sets.

  7. In Vivo Assessment of Elasticity of Child Rib Cortical Bone Using Quantitative Computed Tomography

    Directory of Open Access Journals (Sweden)

    Y. Zhu

    2017-01-01

    Full Text Available Elasticity of the child rib cortical bone is poorly known due to the difficulties in obtaining specimens to perform conventional tests. It was shown on the femoral cortical bone that elasticity is strongly correlated with density for both children and adults through a unique relationship. Thus, it is assumed that the relationships between the elasticity and density of adult rib cortical bones could be expanded to include that of children. This study estimated in vivo the elasticity of the child rib cortical bone using quantitative computed tomography (QCT. Twenty-eight children (from 1 to 18 y.o. were considered. Calibrated QCT images were prescribed for various thoracic pathologies. The Hounsfield units were converted to bone mineral density (BMD. A relationship between the BMD and the elasticity of the rib cortical bone was applied to estimate the elasticity of children’s ribs in vivo. The estimated elasticity increases with growth (7.1 ± 2.5 GPa at 1 y.o. up to 11.6 ± 1.9 GPa at 18 y.o.. This data is in agreement with the few previous values obtained using direct measurements. This methodology paves the way for in vivo assessment of the elasticity of the child cortical bone based on calibrated QCT images.

  8. Quantitative Assessment of Cervical Vertebral Maturation Using Cone Beam Computed Tomography in Korean Girls

    Directory of Open Access Journals (Sweden)

    Bo-Ram Byun

    2015-01-01

    Full Text Available This study was aimed to examine the correlation between skeletal maturation status and parameters from the odontoid process/body of the second vertebra and the bodies of third and fourth cervical vertebrae and simultaneously build multiple regression models to be able to estimate skeletal maturation status in Korean girls. Hand-wrist radiographs and cone beam computed tomography (CBCT images were obtained from 74 Korean girls (6–18 years of age. CBCT-generated cervical vertebral maturation (CVM was used to demarcate the odontoid process and the body of the second cervical vertebra, based on the dentocentral synchondrosis. Correlation coefficient analysis and multiple linear regression analysis were used for each parameter of the cervical vertebrae (P<0.05. Forty-seven of 64 parameters from CBCT-generated CVM (independent variables exhibited statistically significant correlations (P<0.05. The multiple regression model with the greatest R2 had six parameters (PH2/W2, UW2/W2, (OH+AH2/LW2, UW3/LW3, D3, and H4/W4 as independent variables with a variance inflation factor (VIF of <2. CBCT-generated CVM was able to include parameters from the second cervical vertebral body and odontoid process, respectively, for the multiple regression models. This suggests that quantitative analysis might be used to estimate skeletal maturation status.

  9. The study on changes of bone mineral content of mandible by quantitative computed tomography

    International Nuclear Information System (INIS)

    Tamai, Manabu; Ishii, Yasuo

    1996-01-01

    A method to measure bone mineral of mandible has not been established. The bone mineral content (BMC) of the mandible with single energy quantitative computed tomography (SEQCT), which was compared with that of the spine, was discussed. The subjects were 104 healthy persons (54 males and 50 females, age range: 21-69) and 33 patients of mandibular atrophy (10 males and 23 females, age range: 46-87). The BMC changes of the mandible differed according to sex. In males BMC of trabecular bone and cortical bone decreased slightly after 40 and 30 years of age respectively. In females, BMC decreased consistently during menopause. BMC of the spine tended to decrease with aging, especially in females. In males having mandibular atrophy, the BMC of trabecular bone of the mandible decreased, and that of cortical bone of the mandible increased with aging. In females having atrophy, the BMC of trabecular bone and cortical bone of the mandible decreased with aging. The BMC of the mandible was correlated with the length of the denture-wearing time in males. In females, it appears that the BMC of the mandible participates in estrogen deficiency like the BMC of the spine. From the above, measurement of the BMC of the mandible by SEQCT was considered to be very useful for grasping the severity and progressive rate, and other conditions of alveolar ridge atrophy and determining the remedial course. (author)

  10. Evaluation of bone mineral density with dual energy quantitative computed tomography (DEQCT)

    International Nuclear Information System (INIS)

    Ito, Masako; Hayashi, Kuniaki; Yamada, Naoyuki.

    1989-01-01

    The purpose of this study was twofold: to investigate the precision and accuracy of dual energy quantitative computed tomography (QCT) and to investigate age-related changes of bone marrow density (BMD) in patients without metabolic disorders. Rapid kilovolt peak switching system, with which SOMATOM DR-H CT is equipped, allows dual energy scanning. KV-separated images and material-separated images were calculated from dual energy scan data. KV-separated data was regarded as single energy QCT. In phantom studies, dipotassium hydrogen phosphate solution, water, and ethanol were used to simulate bone mineral, lean soft tissue, and fat, respectively. Values of BMD obtained by dual energy scanning method had an error of 5.5% per 10% increase of fat, as compared with 12% for BMD values obtained by single energy scanning method. However, single energy scanning method had a higher precision than dual energy scanning method in determining BMD. The selection of CT section is considered most important in the clinical determination of BMD. In a study of age-related changes of BMD in the vertebral trabecular and cortical bones in 161 patients, BMD was found to have two peaks for women in their twenties and thirties, and one peak for men in their twenties. Bone marrow density rapidly declined among women aged 50 years or more. These results suggest that the content of fat in the trabecular bone may increase progressively after the age of 40, regardless of sex. (N.K.)

  11. Role of peripheral quantitative computed tomography in identifying disuse osteoporosis in paraplegia

    International Nuclear Information System (INIS)

    Coupaud, Sylvie; McLean, Alan N.; Allan, David B.

    2009-01-01

    Disuse osteoporosis is a major long-term health consequence of spinal cord injury (SCI) that still needs to be addressed. Its management in SCI should begin with accurate diagnosis, followed by targeted treatments in the most vulnerable subgroups. We present data quantifying disuse osteoporosis in a cross-section of the Scottish paraplegic population to identify subgroups with lowest bone mineral density (BMD). Forty-seven people with chronic SCI at levels T2-L2 were scanned using peripheral quantitative computed tomography at four tibial sites and two femoral sites, at the Queen Elizabeth National Spinal Injuries Unit, Glasgow (UK). At the distal epiphyses, trabecular BMD (BMDtrab), total BMD, total bone cross-sectional area (CSA) and bone mineral content (BMC) were determined. In the diaphyses, cortical BMD, total bone CSA, cortical CSA and BMC were calculated. Bone, muscle and fat CSAs were estimated in the lower leg and thigh. BMDtrab decreased exponentially with time since injury at different rates in the tibia and femur. At most sites, female paraplegics had significantly lower BMC, total bone CSA and muscle CSA than male paraplegics. Subjects with lumbar SCI tended to have lower bone values and smaller muscle CSAs than in thoracic SCI. At the distal epiphyses of the tibia and femur, there is generally a rapid and extensive reduction in BMDtrab after SCI. Female subjects, and those with lumbar SCI, tend to have lower bone values than males or those with thoracic SCI, respectively. (orig.)

  12. Assessing vertebral fracture risk on volumetric quantitative computed tomography by geometric characterization of trabecular bone structure

    Science.gov (United States)

    Checefsky, Walter A.; Abidin, Anas Z.; Nagarajan, Mahesh B.; Bauer, Jan S.; Baum, Thomas; Wismüller, Axel

    2016-03-01

    The current clinical standard for measuring Bone Mineral Density (BMD) is dual X-ray absorptiometry, however more recently BMD derived from volumetric quantitative computed tomography has been shown to demonstrate a high association with spinal fracture susceptibility. In this study, we propose a method of fracture risk assessment using structural properties of trabecular bone in spinal vertebrae. Experimental data was acquired via axial multi-detector CT (MDCT) from 12 spinal vertebrae specimens using a whole-body 256-row CT scanner with a dedicated calibration phantom. Common image processing methods were used to annotate the trabecular compartment in the vertebral slices creating a circular region of interest (ROI) that excluded cortical bone for each slice. The pixels inside the ROI were converted to values indicative of BMD. High dimensional geometrical features were derived using the scaling index method (SIM) at different radii and scaling factors (SF). The mean BMD values within the ROI were then extracted and used in conjunction with a support vector machine to predict the failure load of the specimens. Prediction performance was measured using the root-mean-square error (RMSE) metric and determined that SIM combined with mean BMD features (RMSE = 0.82 +/- 0.37) outperformed MDCT-measured mean BMD (RMSE = 1.11 +/- 0.33) (p biomechanical strength prediction in vertebrae can be significantly improved through the use of SIM-derived texture features from trabecular bone.

  13. Characterizing trabecular bone structure for assessing vertebral fracture risk on volumetric quantitative computed tomography

    Science.gov (United States)

    Nagarajan, Mahesh B.; Checefsky, Walter A.; Abidin, Anas Z.; Tsai, Halley; Wang, Xixi; Hobbs, Susan K.; Bauer, Jan S.; Baum, Thomas; Wismüller, Axel

    2015-03-01

    While the proximal femur is preferred for measuring bone mineral density (BMD) in fracture risk estimation, the introduction of volumetric quantitative computed tomography has revealed stronger associations between BMD and spinal fracture status. In this study, we propose to capture properties of trabecular bone structure in spinal vertebrae with advanced second-order statistical features for purposes of fracture risk assessment. For this purpose, axial multi-detector CT (MDCT) images were acquired from 28 spinal vertebrae specimens using a whole-body 256-row CT scanner with a dedicated calibration phantom. A semi-automated method was used to annotate the trabecular compartment in the central vertebral slice with a circular region of interest (ROI) to exclude cortical bone; pixels within were converted to values indicative of BMD. Six second-order statistical features derived from gray-level co-occurrence matrices (GLCM) and the mean BMD within the ROI were then extracted and used in conjunction with a generalized radial basis functions (GRBF) neural network to predict the failure load of the specimens; true failure load was measured through biomechanical testing. Prediction performance was evaluated with a root-mean-square error (RMSE) metric. The best prediction performance was observed with GLCM feature `correlation' (RMSE = 1.02 ± 0.18), which significantly outperformed all other GLCM features (p biomechanical strength prediction in spinal vertebrae can be significantly improved through characterization of trabecular bone structure with GLCM-derived texture features.

  14. Role of peripheral quantitative computed tomography in identifying disuse osteoporosis in paraplegia

    Energy Technology Data Exchange (ETDEWEB)

    Coupaud, Sylvie [University of Glasgow, Centre for Rehabilitation Engineering, Department of Mechanical Engineering, Glasgow (United Kingdom); Southern General Hospital, Queen Elizabeth National Spinal Injuries Unit, Glasgow (United Kingdom); McLean, Alan N.; Allan, David B. [Southern General Hospital, Queen Elizabeth National Spinal Injuries Unit, Glasgow (United Kingdom)

    2009-10-15

    Disuse osteoporosis is a major long-term health consequence of spinal cord injury (SCI) that still needs to be addressed. Its management in SCI should begin with accurate diagnosis, followed by targeted treatments in the most vulnerable subgroups. We present data quantifying disuse osteoporosis in a cross-section of the Scottish paraplegic population to identify subgroups with lowest bone mineral density (BMD). Forty-seven people with chronic SCI at levels T2-L2 were scanned using peripheral quantitative computed tomography at four tibial sites and two femoral sites, at the Queen Elizabeth National Spinal Injuries Unit, Glasgow (UK). At the distal epiphyses, trabecular BMD (BMDtrab), total BMD, total bone cross-sectional area (CSA) and bone mineral content (BMC) were determined. In the diaphyses, cortical BMD, total bone CSA, cortical CSA and BMC were calculated. Bone, muscle and fat CSAs were estimated in the lower leg and thigh. BMDtrab decreased exponentially with time since injury at different rates in the tibia and femur. At most sites, female paraplegics had significantly lower BMC, total bone CSA and muscle CSA than male paraplegics. Subjects with lumbar SCI tended to have lower bone values and smaller muscle CSAs than in thoracic SCI. At the distal epiphyses of the tibia and femur, there is generally a rapid and extensive reduction in BMDtrab after SCI. Female subjects, and those with lumbar SCI, tend to have lower bone values than males or those with thoracic SCI, respectively. (orig.)

  15. Quantitation of postexercise lung thallium-201 uptake during single photon emission computed tomography

    International Nuclear Information System (INIS)

    Kahn, J.K.; Carry, M.M.; McGhie, I.; Pippin, J.J.; Akers, M.S.; Corbett, J.R.

    1989-01-01

    To test the hypothesis that analysis of lung thallium uptake measured during single photon emission computed tomography (SPECT) yields supplementary clinical information as reported for planar imaging, quantitative analysis of lung thallium uptake following maximal exercise was performed in 40 clinically normal subjects (Group 1) and 15 angiographically normal subjects (Group 2). Lung thallium uptake was measured from anterior projection images using a ratio of heart-to-lung activities. Seventy subjects with coronary artery disease (CAD) (Group 3) determined by angiography (greater than or equal to 70% luminal stenosis) underwent thallium perfusion SPECT. Thirty-nine percent of these subjects had multivessel and 61% had single vessel CAD. Lung thallium uptake was elevated in 47 of 70 (67%) Group 3 subjects. Group 3 subjects with elevated lung thallium uptake did not differ from Group 3 subjects with normal lung thallium uptake with respect to extent or distribution of coronary artery disease, left ventricular function, or severity of myocardial ischemia as determined by exercise and redistribution thallium SPECT. Thus, the measurement of thallium lung uptake from anterior projection images obtained during SPECT frequently identifies patients with CAD, but it may not provide supplementary information regarding the extent of myocardial ischemia or ventricular dysfunction

  16. The study on changes of bone mineral content of mandible by quantitative computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Tamai, Manabu; Ishii, Yasuo [Fukui Medical School, Matsuoka (Japan)

    1996-04-01

    A method to measure bone mineral of mandible has not been established. The bone mineral content (BMC) of the mandible with single energy quantitative computed tomography (SEQCT), which was compared with that of the spine, was discussed. The subjects were 104 healthy persons (54 males and 50 females, age range: 21-69) and 33 patients of mandibular atrophy (10 males and 23 females, age range: 46-87). The BMC changes of the mandible differed according to sex. In males BMC of trabecular bone and cortical bone decreased slightly after 40 and 30 years of age respectively. In females, BMC decreased consistently during menopause. BMC of the spine tended to decrease with aging, especially in females. In males having mandibular atrophy, the BMC of trabecular bone of the mandible decreased, and that of cortical bone of the mandible increased with aging. In females having atrophy, the BMC of trabecular bone and cortical bone of the mandible decreased with aging. The BMC of the mandible was correlated with the length of the denture-wearing time in males. In females, it appears that the BMC of the mandible participates in estrogen deficiency like the BMC of the spine. From the above, measurement of the BMC of the mandible by SEQCT was considered to be very useful for grasping the severity and progressive rate, and other conditions of alveolar ridge atrophy and determining the remedial course. (author).

  17. Evaluation of dental enamel caries assessment using Quantitative Light Induced Fluorescence and Optical Coherence Tomography.

    Science.gov (United States)

    Maia, Ana Marly Araújo; de Freitas, Anderson Zanardi; de L Campello, Sergio; Gomes, Anderson Stevens Leônidas; Karlsson, Lena

    2016-06-01

    An in vitro study of morphological alterations between sound dental structure and artificially induced white spot lesions in human teeth, was performed through the loss of fluorescence by Quantitative Light-Induced Fluorescence (QLF) and the alterations of the light attenuation coefficient by Optical Coherence Tomography (OCT). To analyze the OCT images using a commercially available system, a special algorithm was applied, whereas the QLF images were analyzed using the software available in the commercial system employed. When analyzing the sound region against white spot lesions region by QLF, a reduction in the fluorescence intensity was observed, whilst an increase of light attenuation by the OCT system occurred. Comparison of the percentage of alteration between optical properties of sound and artificial enamel caries regions showed that OCT processed images through the attenuation of light enhanced the tooth optical alterations more than fluorescence detected by QLF System. QLF versus OCT imaging of enamel caries: a photonics assessment. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Quantitative selenium-75-cholesterol imaging and computed tomography of the adrenal glands in Conn's syndrome

    International Nuclear Information System (INIS)

    Miller, J.L.

    1982-01-01

    Six consecutive patients with biochemically proven primary aldosteronism (4 with unilateral aldosteronomas and 2 with bilateral hyperplasia) underwent imaging with 75 Se-selenomethyl-nor-cholesterol (Scintadren; Radiochemical Centre, Amersham, UK) and computed tomography (CT) of the adrenal glands to aid in lateralizing unilateral aldosterone-producing adenomas (APA) and to differentiate APA from idiopathic adrenal hyperplasia (IAH). Scintadren quantitative imaging alone was successful in lateralizing the lesion in all 4 cases of unilateral APA; mean uptake by the affected adrenal gland was 0,47% of the administered dose as against 0,23% in the normal gland (P smaller than 0,01). The mean uptake ratio for the adenomatous as against the normal gland was 2,03 (range 1,75-2,21), which was significantly greater than the uptake ratio of 0,82 in 4 normal individuals (P smaller than 0,01). CT lateralized all the APAs. In the 2 cases of IAH, Scintadren uptake was bilaterally increased in one case in which CT was normal, whereas in the other case Scintadren uptakes were normal while CT showed two abnormal glands. The overall diagnostic yield for Scintadren was 83%; the figure for CT was also 83%. When the results of Scintadren imaging and CT are pooled, the accuracy in lateralizing APAs and differentiating APA from IAH as a cause of Conn's syndrome is 100%

  19. Risk of vertebral insufficiency fractures in relation to compressive strength predicted by quantitative computed tomography

    International Nuclear Information System (INIS)

    Biggemann, M.; Hilweg, D.; Seidel, S.; Horst, M.; Brinckmann, P.

    1991-01-01

    Vertebral insufficiency fractures may result from excessive loading of normal and routine loading of osteoporotic spines. Fractures occur when the mechanical load exceeds the vertebral compressive strength, i.e., the maximum load a vertebra can tolerate. Vertebral compressive strength is determined by trabecular bone density and the size of end-plate area. Both parameters can be measured non-invasively by quanti-tative computed tomography (QCT). In 75 patients compressive strength (i.e., trabecular bone density and endplate area) of the vertebra L3 was determined using QCT. In addition, conventional radiographs of the spines were analysed for the prevalence of insufficiency fractures in each case. By relating fracture prevalence to strength, 3 fracture risk groups were found: a high-risk group with strength values of L3 5 kN and a fracture risk near 0 percent. Biomechanical measurements and model calculations indicate that spinal loads of 3 to 4 kN at L3/4 will be common in everyday activities. These data and the results described above suggest that spines with strength values of L3<3 kN are at an extremely high risk of insufficiency fractures in daily life. Advantages of fracture risk assessment by strength determination over risk estimation based on clinically used trabecular bone density measurements are discussed. (author). 18 refs.; 4 figs

  20. Tomography

    International Nuclear Information System (INIS)

    1985-01-01

    Already widely accepted in medicine, tomography can also be useful in industry. The theory behind tomography and a demonstration of the technique to inspect a motorcycle carburetor is presented. To demonstrate the potential of computer assisted tomography (CAT) to accurately locate defects in three dimensions, a sectioned 5 cm gate valve with a shrink cavity made visible by the sectioning was tomographically imaged using a Co-60 source. The tomographic images revealed a larger cavity below the sectioned surface. The position of this cavity was located with an in-plane and axial precision of approximately +-1 mm. The volume of the cavity was estimated to be approximately 40 mm 3

  1. Quantitative computed tomography measurements of emphysema for diagnosing asthma-chronic obstructive pulmonary disease overlap syndrome

    Science.gov (United States)

    Xie, Mengshuang; Wang, Wei; Dou, Shuang; Cui, Liwei; Xiao, Wei

    2016-01-01

    Background The diagnostic criteria of asthma–COPD overlap syndrome (ACOS) are controversial. Emphysema is characteristic of COPD and usually does not exist in typical asthma patients. Emphysema in patients with asthma suggests the coexistence of COPD. Quantitative computed tomography (CT) allows repeated evaluation of emphysema noninvasively. We investigated the value of quantitative CT measurements of emphysema in the diagnosis of ACOS. Methods This study included 404 participants; 151 asthma patients, 125 COPD patients, and 128 normal control subjects. All the participants underwent pulmonary function tests and a high-resolution CT scan. Emphysema measurements were taken with an Airway Inspector software. The asthma patients were divided into high and low emphysema index (EI) groups based on the percentage of low attenuation areas less than −950 Hounsfield units. The characteristics of asthma patients with high EI were compared with those having low EI or COPD. Results The normal value of percentage of low attenuation areas less than −950 Hounsfield units in Chinese aged >40 years was 2.79%±2.37%. COPD patients indicated more severe emphysema and more upper-zone-predominant distribution of emphysema than asthma patients or controls. Thirty-two (21.2%) of the 151 asthma patients had high EI. Compared with asthma patients with low EI, those with high EI were significantly older, more likely to be male, had more pack-years of smoking, had more upper-zone-predominant distribution of emphysema, and had greater airflow limitation. There were no significant differences in sex ratios, pack-years of smoking, airflow limitation, or emphysema distribution between asthma patients with high EI and COPD patients. A greater number of acute exacerbations were seen in asthma patients with high EI compared with those with low EI or COPD. Conclusion Asthma patients with high EI fulfill the features of ACOS, as described in the Global Initiative for Asthma and Global

  2. Quantitative pre-clinical screening of therapeutics for joint diseases using contrast enhanced micro-computed tomography.

    Science.gov (United States)

    Willett, N J; Thote, T; Hart, M; Moran, S; Guldberg, R E; Kamath, R V

    2016-09-01

    The development of effective therapies for cartilage protection has been limited by a lack of efficient quantitative cartilage imaging modalities in pre-clinical in vivo models. Our objectives were two-fold: first, to validate a new contrast-enhanced 3D imaging analysis technique, equilibrium partitioning of an ionic contrast agent-micro computed tomography (EPIC-μCT), in a rat medial meniscal transection (MMT) osteoarthritis (OA) model; and second, to quantitatively assess the sensitivity of EPIC-μCT to detect the effects of matrix metalloproteinase inhibitor (MMPi) therapy on cartilage degeneration. Rats underwent MMT surgery and tissues were harvested at 1, 2, and 3 weeks post-surgery or rats received an MMPi or vehicle treatment and tissues harvested 3 weeks post-surgery. Parameters of disease progression were evaluated using histopathology and EPIC-μCT. Correlations and power analyses were performed to compare the techniques. EPIC-μCT was shown to provide simultaneous 3D quantification of multiple parameters, including cartilage degeneration and osteophyte formation. In MMT animals treated with MMPi, OA progression was attenuated, as measured by 3D parameters such as lesion volume and osteophyte size. A post-hoc power analysis showed that 3D parameters for EPIC-μCT were more sensitive than 2D parameters requiring fewer animals to detect a therapeutic effect of MMPi. 2D parameters were comparable between EPIC-μCT and histopathology. This study demonstrated that EPIC-μCT has high sensitivity to provide 3D structural and compositional measurements of cartilage and bone in the joint. EPIC-μCT can be used in combination with histology to provide a comprehensive analysis to screen new potential therapies. Copyright © 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  3. Iterative reconstruction for quantitative computed tomography analysis of emphysema: consistent results using different tube currents

    Directory of Open Access Journals (Sweden)

    Yamashiro T

    2015-02-01

    Full Text Available Tsuneo Yamashiro,1 Tetsuhiro Miyara,1 Osamu Honda,2 Noriyuki Tomiyama,2 Yoshiharu Ohno,3 Satoshi Noma,4 Sadayuki Murayama1 On behalf of the ACTIve Study Group 1Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara, Okinawa, Japan; 2Department of Radiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; 3Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan; 4Department of Radiology, Tenri Hospital, Tenri, Nara, Japan Purpose: To assess the advantages of iterative reconstruction for quantitative computed tomography (CT analysis of pulmonary emphysema. Materials and methods: Twenty-two patients with pulmonary emphysema underwent chest CT imaging using identical scanners with three different tube currents: 240, 120, and 60 mA. Scan data were converted to CT images using Adaptive Iterative Dose Reduction using Three Dimensional Processing (AIDR3D and a conventional filtered-back projection mode. Thus, six scans with and without AIDR3D were generated per patient. All other scanning and reconstruction settings were fixed. The percent low attenuation area (LAA%; < -950 Hounsfield units and the lung density 15th percentile were automatically measured using a commercial workstation. Comparisons of LAA% and 15th percentile results between scans with and without using AIDR3D were made by Wilcoxon signed-rank tests. Associations between body weight and measurement errors among these scans were evaluated by Spearman rank correlation analysis. Results: Overall, scan series without AIDR3D had higher LAA% and lower 15th percentile values than those with AIDR3D at each tube current (P<0.0001. For scan series without AIDR3D, lower tube currents resulted in higher LAA% values and lower 15th percentiles. The extent of emphysema was significantly different between each pair among scans when not using AIDR3D (LAA%, P<0.0001; 15th percentile, P<0.01, but was not

  4. Quantitative spectral K-edge imaging in preclinical photon-counting x-ray computed tomography.

    Science.gov (United States)

    de Vries, Anke; Roessl, Ewald; Kneepkens, Esther; Thran, Axel; Brendel, Bernhard; Martens, Gerhard; Proska, Roland; Nicolay, Klaas; Grüll, Holger

    2015-04-01

    The objective of this study was to investigate the feasibility and the accuracy of spectral computed tomography (spectral CT) to determine the tissue concentrations and localization of high-attenuation, iodine-based contrast agents in mice. Iodine tissue concentrations determined with spectral CT are compared with concentrations measured with single-photon emission computed tomography (SPECT) and inductively coupled plasma mass spectrometry (ICP-MS). All animal procedures were performed according to the US National Institutes of Health principles of laboratory animal care and were approved by the ethical review committee of Maastricht, The Netherlands. Healthy Swiss mice (n = 4) were injected with an iodinated emulsion radiolabeled with indium as multimodal contrast agent for CT and SPECT. The CT and SPECT scans were acquired using a dedicated small-animal SPECT/CT system. Subsequently, scans were performed with a preclinical spectral CT scanner equipped with a photon-counting detector and 6 energy threshold levels. Quantitative data analysis of SPECT and spectral CT scans were obtained using 3-dimensional volumes-of-interest drawing methods. The ICP-MS on dissected organs was performed to determine iodine uptake per organ and was compared with the amounts determined from spectral CT and SPECT. Iodine concentrations obtained with image-processed spectral CT data correlated well with data obtained either with noninvasive SPECT imaging (slope = 0.96, r = 0.75) or with ICP-MS (slope = 0.99, r = 0.89) in tissue samples. This preclinical proof-of-concept study shows the in vivo quantification of iodine concentrations in tissues using spectral CT. Our multimodal imaging approach with spectral CT and SPECT using radiolabeled iodinated emulsions together with ICP-based quantification allows a direct comparison of all methods. Benchmarked against ICP-MS data, spectral CT in the present implementation shows a slight underestimation of organ iodine concentrations compared

  5. Novel application of quantitative single-photon emission computed-tomography/computed tomography to predict early response to methimazole in Graves' disease

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Joo; Bang, Ji In; Kim, Ji Young; Moon, Jae Hoon [Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam (Korea, Republic of); So, Young [Dept. of Nuclear Medicine, Konkuk University Medical Center, Seoul (Korea, Republic of); Lee, Won Woo [Institute of Radiation Medicine, Medical Research Center, Seoul National University, Seoul (Korea, Republic of)

    2017-06-15

    Since Graves' disease (GD) is resistant to antithyroid drugs (ATDs), an accurate quantitative thyroid function measurement is required for the prediction of early responses to ATD. Quantitative parameters derived from the novel technology, single-photon emission computed tomography/computed tomography (SPECT/CT), were investigated for the prediction of achievement of euthyroidism after methimazole (MMI) treatment in GD. A total of 36 GD patients (10 males, 26 females; mean age, 45.3 ± 13.8 years) were enrolled for this study, from April 2015 to January 2016. They underwent quantitative thyroid SPECT/CT 20 minutes post-injection of {sup 99m}Tc-pertechnetate (5 mCi). Association between the time to biochemical euthyroidism after MMI treatment and uptake, standardized uptake value (SUV), functional thyroid mass (SUVmean × thyroid volume) from the SPECT/CT, and clinical/biochemical variables, were investigated. GD patients had a significantly greater %uptake (6.9 ± 6.4%) than historical control euthyroid patients (n = 20, 0.8 ± 0.5%, p < 0.001) from the same quantitative SPECT/CT protocol. Euthyroidism was achieved in 14 patients at 156 ± 62 days post-MMI treatment, but 22 patients had still not achieved euthyroidism by the last follow-up time-point (208 ± 80 days). In the univariate Cox regression analysis, the initial MMI dose (p = 0.014), %uptake (p = 0.015), and functional thyroid mass (p = 0.016) were significant predictors of euthyroidism in response to MMI treatment. However, only uptake remained significant in a multivariate Cox regression analysis (p = 0.034). A uptake cutoff of 5.0% dichotomized the faster responding versus the slower responding GD patients (p = 0.006). A novel parameter of thyroid uptake from quantitative SPECT/CT is a predictive indicator of an early response to MMI in GD patients.

  6. Quantitative analysis of computed tomography images and early detection of cerebral edema for pediatric traumatic brain injury patients: retrospective study.

    Science.gov (United States)

    Kim, Hakseung; Kim, Gwang-dong; Yoon, Byung C; Kim, Keewon; Kim, Byung-Jo; Choi, Young Hun; Czosnyka, Marek; Oh, Byung-Mo; Kim, Dong-Joo

    2014-10-22

    The purpose of this study was to identify whether the distribution of Hounsfield Unit (HU) values across the intracranial area in computed tomography (CT) images can be used as an effective diagnostic tool for determining the severity of cerebral edema in pediatric traumatic brain injury (TBI) patients. CT images, medical records and radiology reports on 70 pediatric patients were collected. Based on radiology reports and the Marshall classification, the patients were grouped as mild edema patients (n=37) or severe edema patients (n=33). Automated quantitative analysis using unenhanced CT images was applied to eliminate artifacts and identify the difference in HU value distribution across the intracranial area between these groups. The proportion of pixels with HU=17 to 24 was highly correlated with the existence of severe cerebral edema (P<0.01). This proportion was also able to differentiate patients who developed delayed cerebral edema from mild TBI patients. A significant difference between deceased patients and surviving patients in terms of the HU distribution came from the proportion of pixels with HU=19 to HU=23 (P<0.01). The proportion of pixels with an HU value of 17 to 24 in the entire cerebral area of a non-enhanced CT image can be an effective basis for evaluating the severity of cerebral edema. Based on this result, we propose a novel approach for the early detection of severe cerebral edema.

  7. In situ flash x-ray high-speed computed tomography for the quantitative analysis of highly dynamic processes

    Science.gov (United States)

    Moser, Stefan; Nau, Siegfried; Salk, Manfred; Thoma, Klaus

    2014-02-01

    The in situ investigation of dynamic events, ranging from car crash to ballistics, often is key to the understanding of dynamic material behavior. In many cases the important processes and interactions happen on the scale of milli- to microseconds at speeds of 1000 m s-1 or more. Often, 3D information is necessary to fully capture and analyze all relevant effects. High-speed 3D-visualization techniques are thus required for the in situ analysis. 3D-capable optical high-speed methods often are impaired by luminous effects and dust, while flash x-ray based methods usually deliver only 2D data. In this paper, a novel 3D-capable flash x-ray based method, in situ flash x-ray high-speed computed tomography is presented. The method is capable of producing 3D reconstructions of high-speed processes based on an undersampled dataset consisting of only a few (typically 3 to 6) x-ray projections. The major challenges are identified, discussed and the chosen solution outlined. The application is illustrated with an exemplary application of a 1000 m s-1 high-speed impact event on the scale of microseconds. A quantitative analysis of the in situ measurement of the material fragments with a 3D reconstruction with 1 mm voxel size is presented and the results are discussed. The results show that the HSCT method allows gaining valuable visual and quantitative mechanical information for the understanding and interpretation of high-speed events.

  8. Image interpolation allows accurate quantitative bone morphometry in registered micro-computed tomography scans.

    Science.gov (United States)

    Schulte, Friederike A; Lambers, Floor M; Mueller, Thomas L; Stauber, Martin; Müller, Ralph

    2014-04-01

    Time-lapsed in vivo micro-computed tomography is a powerful tool to analyse longitudinal changes in the bone micro-architecture. Registration can overcome problems associated with spatial misalignment between scans; however, it requires image interpolation which might affect the outcome of a subsequent bone morphometric analysis. The impact of the interpolation error itself, though, has not been quantified to date. Therefore, the purpose of this ex vivo study was to elaborate the effect of different interpolator schemes [nearest neighbour, tri-linear and B-spline (BSP)] on bone morphometric indices. None of the interpolator schemes led to significant differences between interpolated and non-interpolated images, with the lowest interpolation error found for BSPs (1.4%). Furthermore, depending on the interpolator, the processing order of registration, Gaussian filtration and binarisation played a role. Independent from the interpolator, the present findings suggest that the evaluation of bone morphometry should be done with images registered using greyscale information.

  9. Sparse reconstruction for quantitative bioluminescence tomography based on the incomplete variables truncated conjugate gradient method.

    Science.gov (United States)

    He, Xiaowei; Liang, Jimin; Wang, Xiaorui; Yu, Jingjing; Qu, Xiaochao; Wang, Xiaodong; Hou, Yanbin; Chen, Duofang; Liu, Fang; Tian, Jie

    2010-11-22

    In this paper, we present an incomplete variables truncated conjugate gradient (IVTCG) method for bioluminescence tomography (BLT). Considering the sparse characteristic of the light source and insufficient surface measurement in the BLT scenarios, we combine a sparseness-inducing (ℓ1 norm) regularization term with a quadratic error term in the IVTCG-based framework for solving the inverse problem. By limiting the number of variables updated at each iterative and combining a variable splitting strategy to find the search direction more efficiently, it obtains fast and stable source reconstruction, even without a priori information of the permissible source region and multispectral measurements. Numerical experiments on a mouse atlas validate the effectiveness of the method. In vivo mouse experimental results further indicate its potential for a practical BLT system.

  10. Eigenspectra optoacoustic tomography achieves quantitative blood oxygenation imaging deep in tissues

    Science.gov (United States)

    Tzoumas, Stratis; Nunes, Antonio; Olefir, Ivan; Stangl, Stefan; Symvoulidis, Panagiotis; Glasl, Sarah; Bayer, Christine; Multhoff, Gabriele; Ntziachristos, Vasilis

    2016-06-01

    Light propagating in tissue attains a spectrum that varies with location due to wavelength-dependent fluence attenuation, an effect that causes spectral corruption. Spectral corruption has limited the quantification accuracy of optical and optoacoustic spectroscopic methods, and impeded the goal of imaging blood oxygen saturation (sO2) deep in tissues; a critical goal for the assessment of oxygenation in physiological processes and disease. Here we describe light fluence in the spectral domain and introduce eigenspectra multispectral optoacoustic tomography (eMSOT) to account for wavelength-dependent light attenuation, and estimate blood sO2 within deep tissue. We validate eMSOT in simulations, phantoms and animal measurements and spatially resolve sO2 in muscle and tumours, validating our measurements with histology data. eMSOT shows substantial sO2 accuracy enhancement over previous optoacoustic methods, potentially serving as a valuable tool for imaging tissue pathophysiology.

  11. Eigenspectra optoacoustic tomography achieves quantitative blood oxygenation imaging deep in tissues.

    Science.gov (United States)

    Tzoumas, Stratis; Nunes, Antonio; Olefir, Ivan; Stangl, Stefan; Symvoulidis, Panagiotis; Glasl, Sarah; Bayer, Christine; Multhoff, Gabriele; Ntziachristos, Vasilis

    2016-06-30

    Light propagating in tissue attains a spectrum that varies with location due to wavelength-dependent fluence attenuation, an effect that causes spectral corruption. Spectral corruption has limited the quantification accuracy of optical and optoacoustic spectroscopic methods, and impeded the goal of imaging blood oxygen saturation (sO2) deep in tissues; a critical goal for the assessment of oxygenation in physiological processes and disease. Here we describe light fluence in the spectral domain and introduce eigenspectra multispectral optoacoustic tomography (eMSOT) to account for wavelength-dependent light attenuation, and estimate blood sO2 within deep tissue. We validate eMSOT in simulations, phantoms and animal measurements and spatially resolve sO2 in muscle and tumours, validating our measurements with histology data. eMSOT shows substantial sO2 accuracy enhancement over previous optoacoustic methods, potentially serving as a valuable tool for imaging tissue pathophysiology.

  12. Assessment of the bone mineral density in the lumbar vertebrae of newborns by quantitative computed tomography

    International Nuclear Information System (INIS)

    Braillon, P.M.; Lapillonne, A.; Ho, P.S.; Bouvier, R.; Bochu, M.; Salle, B.L.

    1996-01-01

    Objective. To assess the true mineral density (BMD, in g/cm 3 ) of the lumbar spine in newborns. Design and patients. A post-mortem analysis of five infants with gestational ages ranging from 35 to 40 weeks, and birth weights from 2765 to 3200 g, was conducted using dual-energy quantitative computed tomography (QCT; Siemens Somatom DR). A 2 or 4 mm thick slice was obtained for each lumbar vertebra from L1 to L4. The density measured in these vertebrae was corrected by reference to a solid phantom (Osteo-CT) measured simultaneously. A three-dimensional image of the spine (Elscint CT Twin), as well as a photomicrograph of histological preparation from L2 vertebra, were also obtained in another term baby for comparison with the CT results. Results and conclusions. In the range of values studied, the vertebral densities were not dependent on birth weight. BMD values measured in L2, L3 and L4 were not significantly different, but were 10% lower than in L1 in four of five infants. The spatial resolution of the QCT protocol used (0.4 mm) did not permit the differentiation of trabecular and cortical bone, and the vertebral bodies appeared very homogeneous and dense, with a mean density value of 210±30 mg Ca/cm 3 , which is 2.5 times higher than the mean maximum value found in young normal adults. These preliminary results highlight the potential of QCT in neonatology. Special protocols will, however, need to be developed for in vivo measurements in this particular paediatric field. (orig.). With 4 figs., 2 tabs

  13. Tomography

    International Nuclear Information System (INIS)

    Barrett, H.H.; Gordon, S.; Swindell, W.

    1980-01-01

    Apparatus is described for generating a two-dimensional back-projected image of a slice of an object in tomography. The apparatus uses optical techniques to perform the functions of filtering and back projection. Central to the technique is a cylindrical drum which rotates at a fast rate and whose rotational axis tilts at a slower rate. The novel method overcomes the problem of image blurring due to motion which occurs in many tomographic techniques. It also has the advantages of being less expensive and simpler compared to tomography using digital processing techniques which require fast computers. (UK)

  14. Relationship Between Quantitative Adverse Plaque Features From Coronary Computed Tomography Angiography and Downstream Impaired Myocardial Flow Reserve by 13N-Ammonia Positron Emission Tomography: A Pilot Study.

    Science.gov (United States)

    Dey, Damini; Diaz Zamudio, Mariana; Schuhbaeck, Annika; Juarez Orozco, Luis Eduardo; Otaki, Yuka; Gransar, Heidi; Li, Debiao; Germano, Guido; Achenbach, Stephan; Berman, Daniel S; Meave, Aloha; Alexanderson, Erick; Slomka, Piotr J

    2015-10-01

    We investigated the relationship of quantitative plaque features from coronary computed tomography (CT) angiography and coronary vascular dysfunction by impaired myocardial flow reserve (MFR) by (13)N-Ammonia positron emission tomography (PET). Fifty-one patients (32 men, 62.4±9.5 years) underwent combined rest-stress (13)N-ammonia PET and CT angiography scans by hybrid PET/CT. Regional MFR was measured from PET. From CT angiography, 153 arteries were evaluated by semiautomated software, computing arterial noncalcified plaque (NCP), low-density NCP (NCP<30 HU), calcified and total plaque volumes, and corresponding plaque burden (plaque volumex100%/vessel volume), stenosis, remodeling index, contrast density difference (maximum difference in luminal attenuation per unit area in the lesion), and plaque length. Quantitative stenosis, plaque burden, and myocardial mass were combined by boosted ensemble machine-learning algorithm into a composite risk score to predict impaired MFR (MFR≤2.0) by PET in each artery. Nineteen patients had impaired regional MFR in at least 1 territory (41/153 vessels). Patients with impaired regional MFR had higher arterial NCP (32.4% versus 17.2%), low-density NCP (7% versus 4%), and total plaque burden (37% versus 19.3%, P<0.02). In multivariable analysis with 10-fold cross-validation, NCP burden was the most significant predictor of impaired MFR (odds ratio, 1.35; P=0.021 for all). For prediction of impaired MFR with 10-fold cross-validation, receiver operating characteristics area under the curve for the composite score was 0.83 (95% confidence interval, 0.79-0.91) greater than for quantitative stenosis (0.66, 95% confidence interval, 0.57-0.76, P=0.005). Compared with stenosis, arterial NCP burden and a composite score combining quantitative stenosis and plaque burden from CT angiography significantly improves identification of downstream regional vascular dysfunction. © 2015 American Heart Association, Inc.

  15. CLASSIFICATION AND QUANTITATIVE ANALYSIS OF GEOGRAPHIC ATROPHY JUNCTIONAL ZONE USING SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY.

    Science.gov (United States)

    Qu, Jinfeng; Velaga, Swetha Bindu; Hariri, Amir H; Nittala, Muneeswar Gupta; Sadda, Srinivas

    2017-08-22

    The junctional zone at the border of areas of geographic atrophy (GA) in eyes with nonneovascular age-related macular degeneration is an important target region for future therapeutic strategies. The goal of this study was to perform a detailed classification and quantitative characterization of the junctional zone using spectral domain optical coherence tomography. Spectral domain optical coherence tomography volume cube scans (Spectralis OCT, 1024 × 37, Automatic Real Time > 9) were obtained from 15 eyes of 11 patients with GA because of nonneovascular age-related macular degeneration. Volume optical coherence tomography data were imported into previously described validated grading software (3D-OCTOR), and manual segmentation of the retinal pigment epithelium (RPE) and photoreceptor layers was performed on all B-scans (total of 555). Retinal pigment epithelium and photoreceptor defect maps were produced for each case. The borders of the photoreceptor defect area and RPE defect area were delineated individually on separate annotation layers. The two outlines were then superimposed to compare the areas of overlap and nonoverlap. The perimeter of the RPE defect area was calculated by the software in pixels. The superimposed outline of the photoreceptor defect area and the RPE defect area was scrutinized to classify the overlap configuration of the junctional zone into one of three categories: Type 0, exact correspondence between the edge of the RPE defect and photoreceptor defect; Type 1, loss of photoreceptors outside and beyond the edge of the RPE defect; Type 2, preservation of photoreceptors beyond the edge of the RPE defect. The relative proportion of the various border configurations was expressed as a percentage of the perimeter of the RPE defect. Each configuration was then classified into four subgroups according to irregularity of the RPE band and the presence of debris. Fifteen eyes of 11 patients (mean age: 79.3 ± 4.3 years; range: 79-94 years) were

  16. Positron emission tomography response criteria in solid tumours criteria for quantitative analysis of [18F]-fluorodeoxyglucose positron emission tomography with integrated computed tomography for treatment response assessment in metastasised solid tumours: All that glitters is not gold.

    Science.gov (United States)

    Willemsen, Annelieke E C A B; Vlenterie, Myrella; van Herpen, Carla M L; van Erp, Nielka P; van der Graaf, Winette T A; de Geus-Oei, Lioe-Fee; Oyen, Wim J G

    2016-03-01

    For solid tumours, quantitative analysis of [(18)F]-fluorodeoxyglucose positron emission tomography with integrated computed tomography potentially can have significant value in early response assessment and thereby discrimination between responders and non-responders at an early stage of treatment. Standardised strategies for this analysis have been proposed, and the positron emission tomography response criteria in solid tumours (PERCIST) criteria can be regarded as the current standard to perform quantitative analysis in a research setting, yet is not implemented in daily practice. However, several exceptions and limitations limit the feasibility of PERCIST criteria. In this article, we point out dilemmas that arise when applying proposed criteria like PERCIST on an expansive set of patients with metastasised solid tumours. Clinicians and scientists should be aware of these limitations to prevent that methodological issues impede successful introduction of research data into clinical practice. Therefore, to deliver on the high potential of quantitative imaging, consensus should be reached on a standardised, feasible and clinically useful analysis methodology. This methodology should be applicable in the majority of patients, tumour types and treatments. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. The quantitative assessment of peri-implant bone responses using histomorphometry and micro-computed tomography.

    Science.gov (United States)

    Schouten, Corinne; Meijer, Gert J; van den Beucken, Jeroen J J P; Spauwen, Paul H M; Jansen, John A

    2009-09-01

    In the present study, the effects of implant design and surface properties on peri-implant bone response were evaluated with both conventional histomorphometry and micro-computed tomography (micro-CT), using two geometrically different dental implants (Screw type, St; Push-in, Pi) either or not surface-modified (non-coated, CaP-coated, or CaP-coated+TGF-beta1). After 12 weeks of implantation in a goat femoral condyle model, peri-implant bone response was evaluated in three different zones (inner: 0-500 microm; middle: 500-1000 microm; and outer: 1000-1500 microm) around the implant. Results indicated superiority of conventional histomorphometry over micro-CT, as the latter is hampered by deficits in the discrimination at the implant/tissue interface. Beyond this interface, both analysis techniques can be regarded as complementary. Histomorphometrical analysis showed an overall higher bone volume around St compared to Pi implants, but no effects of surface modification were observed. St implants showed lowest bone volumes in the outer zone, whereas inner zones were lowest for Pi implants. These results implicate that for Pi implants bone formation started from two different directions (contact- and distance osteogenesis). For St implants it was concluded that undersized implantation technique and loosening of bone fragments compress the zones for contact and distant osteogenesis, thereby improving bone volume at the interface significantly.

  18. Quantitative computed tomography determined regional lung mechanics in normal nonsmokers, normal smokers and metastatic sarcoma subjects.

    Directory of Open Access Journals (Sweden)

    Jiwoong Choi

    Full Text Available Extra-thoracic tumors send out pilot cells that attach to the pulmonary endothelium. We hypothesized that this could alter regional lung mechanics (tissue stiffening or accumulation of fluid and inflammatory cells through interactions with host cells. We explored this with serial inspiratory computed tomography (CT and image matching to assess regional changes in lung expansion.We retrospectively assessed 44 pairs of two serial CT scans on 21 sarcoma patients: 12 without lung metastases and 9 with lung metastases. For each subject, two or more serial inspiratory clinically-derived CT scans were retrospectively collected. Two research-derived control groups were included: 7 normal nonsmokers and 12 asymptomatic smokers with two inspiratory scans taken the same day or one year apart respectively. We performed image registration for local-to-local matching scans to baseline, and derived local expansion and density changes at an acinar scale. Welch two sample t test was used for comparison between groups. Statistical significance was determined with a p value < 0.05.Lung regions of metastatic sarcoma patients (but not the normal control group demonstrated an increased proportion of normalized lung expansion between the first and second CT. These hyper-expanded regions were associated with, but not limited to, visible metastatic lung lesions. Compared with the normal control group, the percent of increased normalized hyper-expanded lung in sarcoma subjects was significantly increased (p < 0.05. There was also evidence of increased lung "tissue" volume (non-air components in the hyper-expanded regions of the cancer subjects relative to non-hyper-expanded regions. "Tissue" volume increase was present in the hyper-expanded regions of metastatic and non-metastatic sarcoma subjects. This putatively could represent regional inflammation related to the presence of tumor pilot cell-host related interactions.This new quantitative CT (QCT method for linking

  19. Quantitative parameters of image quality in 64-slice computed tomography angiography of the coronary arteries

    International Nuclear Information System (INIS)

    Ferencik, Maros; Nomura, Cesar H.; Maurovich-Horvat, Pal; Hoffmann, Udo; Pena, Antonio J.; Cury, Ricardo C.; Abbara, Suhny; Nieman, Koen; Fatima, Umaima; Achenbach, Stephan; Brady, Thomas J.

    2006-01-01

    We explored quantitative parameters of image quality in consecutive patients undergoing 64-slice multi-detector computed tomography (MDCT) coronary angiography for clinical reasons. Forty-two patients (36 men, mean age 61 ± 11 years, mean heart rate 63 ± 10 bpm) underwent contrast-enhanced MDCT coronary angiography with a 64-slice scanner (Siemens Sensation 64, 64 mmx 0.6 mm collimation, 330 ms tube rotation, 850 mAs, 120 kV). Two independent observers measured the overall visualized vessel length and the length of the coronary arteries visualized without motion artifacts in curved multiplanar reformatted images. Contrast-to-noise ratio was measured in the proximal and distal segments of the coronary arteries. The mean length of visualized coronary arteries was: left main 12 ± 6 mm, left anterior descending 149 ± 25 mm, left circumflex 89 ± 30 mm, and right coronary artery 161 ± 38 mm. On average, 97 ± 5% of the total visualized vessel length was depicted without motion artifacts (left main 100 ± 0%, left anterior descending 97 ± 6%, left circumflex 98 ± 5%, and right coronary artery 95 ± 6%). In 27 patients with a heart rate ≤65 bpm, 98 ± 4% of the overall visualized vessel length was imaged without motion artifacts, whereas 96 ± 6% of the overall visualized vessel length was imaged without motion artifacts in 15 patients with a heart rate >65 bpm (p < 0.001). The mean contrast-to-noise ratio in all measured coronary arteries was 14.6 ± 4.7 (proximal coronary segments: range 15.1 ± 4.4 to 16.1 ± 5.0, distal coronary segments: range 11.4 ± 4.2 to 15.9 ± 4.9). In conclusion, 64-slice MDCT permits reliable visualization of the coronary arteries with minimal motion artifacts and high CNR in consecutive patients referred for non-invasive MDCT coronary angiography. Low heart rate is an important prerequisite for excellent image quality

  20. Quantitative material decomposition using spectral computed tomography with an energy-resolved photon-counting detector

    International Nuclear Information System (INIS)

    Lee, Seungwan; Choi, Yu-Na; Kim, Hee-Joung

    2014-01-01

    Dual-energy computed tomography (CT) techniques have been used to decompose materials and characterize tissues according to their physical and chemical compositions. However, these techniques are hampered by the limitations of conventional x-ray detectors operated in charge integrating mode. Energy-resolved photon-counting detectors provide spectral information from polychromatic x-rays using multiple energy thresholds. These detectors allow simultaneous acquisition of data in different energy ranges without spectral overlap, resulting in more efficient material decomposition and quantification for dual-energy CT. In this study, a pre-reconstruction dual-energy CT technique based on volume conservation was proposed for three-material decomposition. The technique was combined with iterative reconstruction algorithms by using a ray-driven projector in order to improve the quality of decomposition images and reduce radiation dose. A spectral CT system equipped with a CZT-based photon-counting detector was used to implement the proposed dual-energy CT technique. We obtained dual-energy images of calibration and three-material phantoms consisting of low atomic number materials from the optimal energy bins determined by Monte Carlo simulations. The material decomposition process was accomplished by both the proposed and post-reconstruction dual-energy CT techniques. Linear regression and normalized root-mean-square error (NRMSE) analyses were performed to evaluate the quantitative accuracy of decomposition images. The calibration accuracy of the proposed dual-energy CT technique was higher than that of the post-reconstruction dual-energy CT technique, with fitted slopes of 0.97–1.01 and NRMSEs of 0.20–4.50% for all basis materials. In the three-material phantom study, the proposed dual-energy CT technique decreased the NRMSEs of measured volume fractions by factors of 0.17–0.28 compared to the post-reconstruction dual-energy CT technique. It was concluded that the

  1. Usefulness of quantitative computed tomography for measurement of vertebral bone mineral density in osteoporosis

    International Nuclear Information System (INIS)

    Shaura, Kozo

    1986-01-01

    The present studies were undertaken to elucidate the usefullnes of the qantitative computed tomography in mesurement of bone densites of lumbar spine in senile and postmenopausal osteoporosis. The CT-numbers of the spongiosum of the second lumbar spine and K2HPO4 solusion phantom were mesured in the same series scanning, and the bone densities were displayed as concentrations of K2HPO4 solution (QCT-value). The QCT-values are well related with the bone densities which were mesured with single photon absorptiometor (Norland-Cameron) at one third and one sixth distal ends of radiuses. The QCT-values decrease with aging, and the decrement in female is more remarkable than that in male. The decrement of QCT-value starts at in 3rd decade of their life time. It is defferent from the conclusions those were obtained with the measurement of clavicular cortex index, or single photon absorptiometor. The QCT-values of the patients with lumbargo are lower than those of the patients without lumbargo. The QCT-values of the patients without compression fructure in lumbar spine are higher than those of the patients with compression fructure, but the number of the sites of compression fructures in lumbar spine appears to have no effect on the QCT-values. The QCT-values of postmenopausal osteoporosis were improved by the administration of calcium and 1α-OHVit. D3 (0.5 μg/day. for a year). (author)

  2. Use of ultrafast computed tomography to quantitate regional myocardial perfusion: a preliminary report

    International Nuclear Information System (INIS)

    Rumberger, J.A.; Feiring, A.J.; Lipton, M.J.; Higgins, C.B.; Ell, S.R.; Marcus, M.L.

    1987-01-01

    The purpose of this study was to assess the potential for rapid acquisition computed axial tomography (Imatron C-100) to quantify regional myocardial perfusion. Myocardial and left ventricular cavity contrast clearance curves were constructed after injecting nonionic contrast (1 ml/kg over 2 to 3 seconds) into the inferior vena cava of six anesthetized, closed chest dogs (n = 14). Independent myocardial perfusion measurements were obtained by coincident injection of radiolabeled microspheres into the left atrium during control, intermediate and maximal myocardial vasodilation with adenosine (0.5 to 1.0 mg/kg per min, intravenously, respectively). At each flow state, 40 serial short-axis scans of the left ventricle were taken near end-diastole at the midpapillary muscle level. Contrast clearance curves were generated and analyzed from the left ventricular cavity and posterior papillary muscle regions after excluding contrast recirculation and minimizing partial volume effects. The area under the curve (gamma variate function) was determined for a region of interest placed within the left ventricular cavity. Characteristics of contrast clearance data from the posterior papillary muscle region that were evaluated included the peak myocardial opacification, area under the contrast clearance curve and a contrast clearance time defined by the full width/half maximal extent of the clearance curve. Myocardial perfusion (microspheres) ranged from 35 to 450 ml/100 g per min (mean 167 +/- 125)

  3. Quantitative image analysis of vertebral body architecture - improved diagnosis in osteoporosis based on high-resolution computed tomography

    International Nuclear Information System (INIS)

    Mundinger, A.; Wiesmeier, B.; Dinkel, E.; Helwig, A.; Beck, A.; Schulte Moenting, J.

    1993-01-01

    71 women, 64 post-menopausal, were examined by single-energy quantitative computed tomography (SEQCT) and by high-resolution computed tomography (HRCT) scans through the middle of lumbar vertebral bodies. Computer-assisted image analysis of the high-resolution images assessed trabecular morphometry of the vertebral spongiosa texture. Texture parameters differed in women with and without age-reduced bone density, and in the former group also in patients with and without vertebral fractures. Discriminating parameters were the total number, diameter and variance of trabecular and intertrabecular spaces as well as the trabecular surface (p < 0.05)). A texture index based on these statistically selected morphometric parameters identified a subgroup of patients suffering from fractures due to abnormal spongiosal architecture but with a bone mineral content not indicative for increased fracture risk. The combination of osteodensitometric and trabecular morphometry improves the diagnosis of osteoporosis and may contribute to the prediction of individual fracture risk. (author)

  4. Integration of Quantitative Positron Emission Tomography Absolute Myocardial Blood Flow Measurements in the Clinical Management of Coronary Artery Disease.

    Science.gov (United States)

    Gewirtz, Henry; Dilsizian, Vasken

    2016-05-31

    In the >40 years since planar myocardial imaging with(43)K-potassium was introduced into clinical research and management of patients with coronary artery disease (CAD), diagnosis and treatment have undergone profound scientific and technological changes. One such innovation is the current state-of-the-art hardware and software for positron emission tomography myocardial perfusion imaging, which has advanced it from a strictly research-oriented modality to a clinically valuable tool. This review traces the evolving role of quantitative positron emission tomography measurements of myocardial blood flow in the evaluation and management of patients with CAD. It presents methodology, currently or soon to be available, that offers a paradigm shift in CAD management. Heretofore, radionuclide myocardial perfusion imaging has been primarily qualitative or at best semiquantitative in nature, assessing regional perfusion in relative terms. Thus, unlike so many facets of modern cardiovascular practice and CAD management, which depend, for example, on absolute values of key parameters such as arterial and left ventricular pressures, serum lipoprotein, and other biomarker levels, the absolute levels of rest and maximal myocardial blood flow have yet to be incorporated into routine clinical practice even in most positron emission tomography centers where the potential to do so exists. Accordingly, this review focuses on potential value added for improving clinical CAD practice by measuring the absolute level of rest and maximal myocardial blood flow. Physiological principles and imaging fundamentals necessary to understand how positron emission tomography makes robust, quantitative measurements of myocardial blood flow possible are highlighted. © 2016 American Heart Association, Inc.

  5. Quantitative Fourier Domain Optical Coherence Tomography Imaging of the Ocular Anterior Segment

    Science.gov (United States)

    McNabb, Ryan Palmer

    Clinical imaging within ophthalmology has had transformative effects on ocular health over the last century. Imaging has guided clinicians in their pharmaceutical and surgical treatments of macular degeneration, glaucoma, cataracts and numerous other pathologies. Many of the imaging techniques currently used are photography based and are limited to imaging the surface of ocular structures. This limitation forces clinicians to make assumptions about the underlying tissue which may reduce the efficacy of their diagnoses. Optical coherence tomography (OCT) is a non-invasive, non-ionizing imaging modality that has been widely adopted within the field of ophthalmology in the last 15 years. As an optical imaging technique, OCT utilizes low-coherence interferometry to produce micron-scale three-dimensional datasets of a tissue's structure. Much of the human body consists of tissues that significantly scatter and attenuate optical signals limiting the imaging depth of OCT in those tissues to only 1-2mm. However, the ocular anterior segment is unique among human tissue in that it is primarily transparent or translucent. This allows for relatively deep imaging of tissue structure with OCT and is no longer limited by the optical scattering properties of the tissue. This goal of this work is to develop methods utilizing OCT that offer the potential to reduce the assumptions made by clinicians in their evaluations of their patients' ocular anterior segments. We achieved this by first developing a method to reduce the effects of patient motion during OCT volume acquisitions allowing for accurate, three dimensional measurements of corneal shape. Having accurate corneal shape measurements then allowed us to determine corneal spherical and astigmatic refractive contribution in a given individual. This was then validated in a clinical study that showed OCT better measured refractive change due to surgery than other clinical devices. Additionally, a method was developed to combine

  6. Bone mineral density in renal osteodystrophy: Comparison of dual energy X-ray absorptiometry and quantitative computed tomography

    International Nuclear Information System (INIS)

    Funke, M.; Maeurer, J.; Grabbe, E.; Scheler, F.

    1992-01-01

    Measurements of bone density were carried out in 25 patients on dialysis for terminal renal insufficiency, using quantitative computed tomography (QCT) and dual energy X-ray absorptiometry (DXA). Unlike in subjects with normal kidneys, there was no significant correlation between these methods in this series. Ten patients showed an increase in bone density of the vertebral spongiosa on QCT measurements, which was interpreted as due to osteosclerotic bone changes in renal osteopathy. QCT showed advantages over DXA in demonstrating these changes. (orig.) [de

  7. Theory and preliminary experimental verification of quantitative edge illumination x-ray phase contrast tomography.

    Science.gov (United States)

    Hagen, C K; Diemoz, P C; Endrizzi, M; Rigon, L; Dreossi, D; Arfelli, F; Lopez, F C M; Longo, R; Olivo, A

    2014-04-07

    X-ray phase contrast imaging (XPCi) methods are sensitive to phase in addition to attenuation effects and, therefore, can achieve improved image contrast for weakly attenuating materials, such as often encountered in biomedical applications. Several XPCi methods exist, most of which have already been implemented in computed tomographic (CT) modality, thus allowing volumetric imaging. The Edge Illumination (EI) XPCi method had, until now, not been implemented as a CT modality. This article provides indications that quantitative 3D maps of an object's phase and attenuation can be reconstructed from EI XPCi measurements. Moreover, a theory for the reconstruction of combined phase and attenuation maps is presented. Both reconstruction strategies find applications in tissue characterisation and the identification of faint, weakly attenuating details. Experimental results for wires of known materials and for a biological object validate the theory and confirm the superiority of the phase over conventional, attenuation-based image contrast.

  8. Quantitative wood–adhesive penetration with X-ray computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Paris, Jesse L.; Kamke, Frederick A. (Oregon State U.); (Willamette Valley)

    2015-09-01

    Micro X-ray computed tomography (XCT) was used to analyze the 3D adhesive penetration behavior of different wood–adhesive bondlines. Three adhesives, a phenol formaldehyde (PF), a polymeric diphenylmethane diisocyanate (pMDI), and a hybrid polyvinyl acetate (PVA), all tagged with iodine for enhanced X-ray attenuation, were used to prepare single-bondline laminates in two softwoods, Douglas-fir and loblolly pine, and one hardwood, a hybrid polar. Adhesive penetration depth was measured with two separate calculations, and results were compared with 2D fluorescent micrographs. A total of 54 XCT scans were collected, representing six replicates of each treatment type; each replicate, however, consisted of approximately 1500 individual, cross-section slices stacked along the specimen length. As these adhesives were highly modified, the presented results do not indicate typical behavior for their broader adhesive classes. Still, clear penetration differences were observed between each adhesive type, and between wood species bonded with both the PF and pMDI adhesives. Furthermore, penetration results depended on the calculation method used. Two adhesive types with noticeably different resin distributions in the cured bondline, showed relatively similar penetration depths when calculated with a traditional effective penetration equation. However, when the same data was calculated with a weighted penetration calculation, which accounts for both adhesive area and depth, the results appeared to better represent the different distributions depicted in the photomicrographs and tomograms. Additionally, individual replicate comparisons showed variation due to specimen anatomy, not easily observed or interpreted from 2D images. Finally, 3D views of segmented 3D adhesive phases offered unique, in-situ views of the cured adhesive structures. In particular, voids formed by CO2 bubbles generated during pMDI cure were clearly visible in penetrated columns of the solidified

  9. Predicted cancer risks induced by computed tomography examinations during childhood, by a quantitative risk assessment approach.

    Science.gov (United States)

    Journy, Neige; Ancelet, Sophie; Rehel, Jean-Luc; Mezzarobba, Myriam; Aubert, Bernard; Laurier, Dominique; Bernier, Marie-Odile

    2014-03-01

    The potential adverse effects associated with exposure to ionizing radiation from computed tomography (CT) in pediatrics must be characterized in relation to their expected clinical benefits. Additional epidemiological data are, however, still awaited for providing a lifelong overview of potential cancer risks. This paper gives predictions of potential lifetime risks of cancer incidence that would be induced by CT examinations during childhood in French routine practices in pediatrics. Organ doses were estimated from standard radiological protocols in 15 hospitals. Excess risks of leukemia, brain/central nervous system, breast and thyroid cancers were predicted from dose-response models estimated in the Japanese atomic bomb survivors' dataset and studies of medical exposures. Uncertainty in predictions was quantified using Monte Carlo simulations. This approach predicts that 100,000 skull/brain scans in 5-year-old children would result in eight (90 % uncertainty interval (UI) 1-55) brain/CNS cancers and four (90 % UI 1-14) cases of leukemia and that 100,000 chest scans would lead to 31 (90 % UI 9-101) thyroid cancers, 55 (90 % UI 20-158) breast cancers, and one (90 % UI risks without exposure). Compared to background risks, radiation-induced risks would be low for individuals throughout life, but relative risks would be highest in the first decades of life. Heterogeneity in the radiological protocols across the hospitals implies that 5-10 % of CT examinations would be related to risks 1.4-3.6 times higher than those for the median doses. Overall excess relative risks in exposed populations would be 1-10 % depending on the site of cancer and the duration of follow-up. The results emphasize the potential risks of cancer specifically from standard CT examinations in pediatrics and underline the necessity of optimization of radiological protocols.

  10. Quantitative evaluation of anatomical noise in chest digital tomosynthesis, digital radiography, and computed tomography

    International Nuclear Information System (INIS)

    Lee, D.; Kim, D.; Choi, S.; Kim, H.-J.; Choi, S.; Lee, H.

    2017-01-01

    Lung cancer is currently the worldwide leading cause of death from cancer. Thus, detection of lung cancer at its early stages is critical for improving the survival rate of patients. Chest digital tomosynthesis (CDT) is a recently developed imaging modality, combining many advantages of digital radiography (DR) and computed tomography (CT). This method has the potential to be widely used in the clinical setting. In this study, we introduce a developed CDT R/F system and compare its image quality with those of DR and CT, especially with respect to anatomical noise and lung nodule conspicuity, for LUNGMAN phantoms. The developed CDT R/F system consists of a CsI scintillator flat panel detector, X-ray tube, and tomosynthesis data acquisition geometry. For CDT R/F imaging, 41 projections were acquired at different angles, over the ± 20° angular range, in a linear translation geometry. To evaluate the clinical effectiveness of the CDT R/F system, the acquired images were compared with CT (Philips brilliance CT 64, Philips healthcare, U.S.) and DR (ADR-M, LISTEM, Korea) phantom images in terms of the anatomical noise power spectrum (aNPS). DR images exhibited low conspicuity for a small-size lung nodule, while CDT R/F and CT exhibited relatively high sensitivity for all lung nodule sizes. The aNPS of the CDT R/F system was better than that of DR, by resolving anatomical overlapping problems. In conclusion, the developed CDT R/F system is likely to contribute to early diagnosis of lung cancer, while requiring a relatively low patient dose, compared with CT.

  11. Quantitative evaluation of anatomical noise in chest digital tomosynthesis, digital radiography, and computed tomography

    Science.gov (United States)

    Lee, D.; Choi, S.; Lee, H.; Kim, D.; Choi, S.; Kim, H.-J.

    2017-04-01

    Lung cancer is currently the worldwide leading cause of death from cancer. Thus, detection of lung cancer at its early stages is critical for improving the survival rate of patients. Chest digital tomosynthesis (CDT) is a recently developed imaging modality, combining many advantages of digital radiography (DR) and computed tomography (CT). This method has the potential to be widely used in the clinical setting. In this study, we introduce a developed CDT R/F system and compare its image quality with those of DR and CT, especially with respect to anatomical noise and lung nodule conspicuity, for LUNGMAN phantoms. The developed CDT R/F system consists of a CsI scintillator flat panel detector, X-ray tube, and tomosynthesis data acquisition geometry. For CDT R/F imaging, 41 projections were acquired at different angles, over the ± 20° angular range, in a linear translation geometry. To evaluate the clinical effectiveness of the CDT R/F system, the acquired images were compared with CT (Philips brilliance CT 64, Philips healthcare, U.S.) and DR (ADR-M, LISTEM, Korea) phantom images in terms of the anatomical noise power spectrum (aNPS). DR images exhibited low conspicuity for a small-size lung nodule, while CDT R/F and CT exhibited relatively high sensitivity for all lung nodule sizes. The aNPS of the CDT R/F system was better than that of DR, by resolving anatomical overlapping problems. In conclusion, the developed CDT R/F system is likely to contribute to early diagnosis of lung cancer, while requiring a relatively low patient dose, compared with CT.

  12. First experiences with model based iterative reconstructions influence on quantitative plaque volume and intensity measurements in coronary computed tomography angiography

    International Nuclear Information System (INIS)

    Precht, H.; Kitslaar, P.H.; Broersen, A.; Gerke, O.; Dijkstra, J.; Thygesen, J.; Egstrup, K.; Lambrechtsen, J.

    2017-01-01

    Purpose: Investigate the influence of adaptive statistical iterative reconstruction (ASIR) and the model-based IR (Veo) reconstruction algorithm in coronary computed tomography angiography (CCTA) images on quantitative measurements in coronary arteries for plaque volumes and intensities. Methods: Three patients had three independent dose reduced CCTA performed and reconstructed with 30% ASIR (CTDI vol at 6.7 mGy), 60% ASIR (CTDI vol 4.3 mGy) and Veo (CTDI vol at 1.9 mGy). Coronary plaque analysis was performed for each measured CCTA volumes, plaque burden and intensities. Results: Plaque volume and plaque burden show a decreasing tendency from ASIR to Veo as median volume for ASIR is 314 mm 3 and 337 mm 3 –252 mm 3 for Veo and plaque burden is 42% and 44% for ASIR to 39% for Veo. The lumen and vessel volume decrease slightly from 30% ASIR to 60% ASIR with 498 mm 3 –391 mm 3 for lumen volume and vessel volume from 939 mm 3 to 830 mm 3 . The intensities did not change overall between the different reconstructions for either lumen or plaque. Conclusion: We found a tendency of decreasing plaque volumes and plaque burden but no change in intensities with the use of low dose Veo CCTA (1.9 mGy) compared to dose reduced ASIR CCTA (6.7 mGy & 4.3 mGy), although more studies are warranted. - Highlights: • Veo decrease plaque volumes and plaque burden using low-dose CCTA. • Moving from ASIR 30%, ASIR 60% to Veo did not appear to influence the plaque intensities. • Studies including larger sample size are needed to investigate the effect on plaque.

  13. Studies on the reference values of bone mineral content in Bulgarian women using single energy quantitative computed tomography

    International Nuclear Information System (INIS)

    Tsvetkova, S.; Semova, R.; Lichev, A.; Delov, I.

    1995-01-01

    Quantitative CT assessment of bone mineral content (BMC) is widely used in clinical practice. The results obtained from the examination of every single patient are compared with the reference values for the corresponding age and sex. It is known that BMC shows well recognized genetic, racial, ethnic and other differences. On the other hand, the introduction of different techniques, calibration phantoms, algorithms for choosing the region of interest, statistical models etc. leads to some differences in reference values. The authors present their own studies on the reference values of BMC in Bulgarian women using single energy quantitative computed tomography and a liquid K 2 HPO 4 calibration phantom. Different statistical models for data processing are proposed. The results are compared to the studies of recognized foreign authors. 17 refs., 3 tabs., 5 figs. (author)

  14. Automated high resolution full-field spatial coherence tomography for quantitative phase imaging of human red blood cells

    Science.gov (United States)

    Singla, Neeru; Dubey, Kavita; Srivastava, Vishal; Ahmad, Azeem; Mehta, D. S.

    2018-02-01

    We developed an automated high-resolution full-field spatial coherence tomography (FF-SCT) microscope for quantitative phase imaging that is based on the spatial, rather than the temporal, coherence gating. The Red and Green color laser light was used for finding the quantitative phase images of unstained human red blood cells (RBCs). This study uses morphological parameters of unstained RBCs phase images to distinguish between normal and infected cells. We recorded the single interferogram by a FF-SCT microscope for red and green color wavelength and average the two phase images to further reduced the noise artifacts. In order to characterize anemia infected from normal cells different morphological features were extracted and these features were used to train machine learning ensemble model to classify RBCs with high accuracy.

  15. Quantitative comparison of commercial and non-commercial metal artifact reduction techniques in computed tomography.

    Directory of Open Access Journals (Sweden)

    Dirk Wagenaar

    Full Text Available Typical streak artifacts known as metal artifacts occur in the presence of strongly attenuating materials in computed tomography (CT. Recently, vendors have started offering metal artifact reduction (MAR techniques. In addition, a MAR technique called the metal deletion technique (MDT is freely available and able to reduce metal artifacts using reconstructed images. Although a comparison of the MDT to other MAR techniques exists, a comparison of commercially available MAR techniques is lacking. The aim of this study was therefore to quantify the difference in effectiveness of the currently available MAR techniques of different scanners and the MDT technique.Three vendors were asked to use their preferential CT scanner for applying their MAR techniques. The scans were performed on a Philips Brilliance ICT 256 (S1, a GE Discovery CT 750 HD (S2 and a Siemens Somatom Definition AS Open (S3. The scans were made using an anthropomorphic head and neck phantom (Kyoto Kagaku, Japan. Three amalgam dental implants were constructed and inserted between the phantom's teeth. The average absolute error (AAE was calculated for all reconstructions in the proximity of the amalgam implants.The commercial techniques reduced the AAE by 22.0±1.6%, 16.2±2.6% and 3.3±0.7% for S1 to S3 respectively. After applying the MDT to uncorrected scans of each scanner the AAE was reduced by 26.1±2.3%, 27.9±1.0% and 28.8±0.5% respectively. The difference in efficiency between the commercial techniques and the MDT was statistically significant for S2 (p=0.004 and S3 (p<0.001, but not for S1 (p=0.63.The effectiveness of MAR differs between vendors. S1 performed slightly better than S2 and both performed better than S3. Furthermore, for our phantom and outcome measure the MDT was more effective than the commercial MAR technique on all scanners.

  16. Quantification in emission tomography

    International Nuclear Information System (INIS)

    Buvat, Irene

    2011-11-01

    The objective of this lecture is to understand the possibilities and limitations of the quantitative analysis of single photon emission computed tomography (SPECT) and positron emission tomography (PET) images. It is also to identify the conditions to be fulfilled to obtain reliable quantitative measurements from images. Content: 1 - Introduction: Quantification in emission tomography - definition and challenges; quantification biasing phenomena 2 - Main problems impacting quantification in PET and SPECT: problems, consequences, correction methods, results (Attenuation, scattering, partial volume effect, movement, un-stationary spatial resolution in SPECT, fortuitous coincidences in PET, standardisation in PET); 3 - Synthesis: accessible efficiency, know-how, Precautions, beyond the activity measurement

  17. Dipyridamole 201T1 myocardial perfusion tomography and bull's--eye analysis for quantitative evaluation of CAD

    International Nuclear Information System (INIS)

    Jiang Maosong; Tang Xi

    1992-01-01

    To assess the ability of quantitative analysis of dipyridamole 201 T1 tomography for detecting and localizing coronary artery disease (CAD), 55 patients with angiographically proved CAD ( = 50% stenosis) were studied. All patients underwent dipyridamole 201 T1 myocardial perfusion tomography and coronary arteriography. The overall sensitivity for detection of CAD by Bull's-eye analysis was 89% (50 patients) and 92% (51 patients) with visual analysis. The sensitivity for detecting individual vessel involvement with the Bull'-eye analysis was 88% for LAD. 81% for RCA and 67% for LCX. With visual analysis, the results were 88%, 83% and 58% respectively. The overall rate of detection was 87% in lesions greater than or equal to 75% stenosis vs 59% in those under 75% stenosis (P 201 T1 tomography using Bull's-eye display is a highly accurate reproducible technique for the detection of patients with CAD and the localization of individual coronary vessel, and it offers the potential to quantify the percentage of the abnormally perfused myocardium

  18. Quantitative Estimation for the Effectiveness of Automation

    International Nuclear Information System (INIS)

    Lee, Seung Min; Seong, Poong Hyun

    2012-01-01

    In advanced MCR, various automation systems are applied to enhance the human performance and reduce the human errors in industrial fields. It is expected that automation provides greater efficiency, lower workload, and fewer human errors. However, these promises are not always fulfilled. As the new types of events related to application of the imperfect and complex automation are occurred, it is required to analyze the effects of automation system for the performance of human operators. Therefore, we suggest the quantitative estimation method to analyze the effectiveness of the automation systems according to Level of Automation (LOA) classification, which has been developed over 30 years. The estimation of the effectiveness of automation will be achieved by calculating the failure probability of human performance related to the cognitive activities

  19. Assessment of left ventricular function by electrocardiogram-gated myocardial single photon emission computed tomography using quantitative gated single photon emission computed tomography software

    International Nuclear Information System (INIS)

    Morita, Koichi; Adachi, Itaru; Konno, Masanori

    1999-01-01

    Electrocardiogram (ECG)-gated myocardial single photon emission computed tomography (SPECT) can assess left ventricular (LV) perfusion and function easily using quantitative gated SPECT (QGS) software. ECG-gated SPECT was performed in 44 patients with coronary artery disease under post-stress and resting conditions to assess the values of LV functional parameters, by comparison to LV ejection fraction derived from gated blood pool scan and myocardial characteristics. A good correlation was obtained between ejection fraction using QGS and that using cardiac blood pool scan (r=0.812). Some patients with myocardial ischemia had lower ejection fraction under post-stress compared to resting conditions, indicating post-stress LV dysfunction. LV wall motion and wall thickening were significantly impaired in ischemic and infarcted myocardium, and the degree of abnormality in the infarcted areas was greater than in the ischemia area. LV functional parameters derived using QGS were useful to assess post-stress LV dysfunction and myocardial viability. In conclusion, ECG-gated myocardial SPECT permits simultaneous quantitative assessment of myocardial perfusion and function. (author)

  20. Effect of fluid-filled boreholes on resistivity tomography; Hiteiko tomography ni okeru konaisui no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Sugimoto, Y [DIA Consultants Co. Ltd., Tokyo (Japan)

    1997-10-22

    Theoretical discussions were given on the effect of fluid-filled boreholes on resistivity tomography. The discussions performed incorporation of earth resistance as a method to consider borehole diameters in an FEM calculation using wire elements. The numerical experiment conducted a simulation on the following two objects: resistivity tomography in a horizontal multi-layer structure consisted of layers with resistivity ranging from 10 to 10000 ohm-m, and a model with a slanted low resistivity band existing in a background of 5000 ohm-m. As a result of the discussions, it was made clear that the effect of the boreholes can be corrected by giving earth resistance between the wire elements and natural ground. An improved potential calculating program indicated that the effect of the fluid-filled boreholes in the resistivity tomography generates false images with high resistivity along the bores if the resistivity has high contrast. Incorporating the wire elements into an inverse analysis model reduces the false images and improves the accuracy. 1 ref., 12 figs.

  1. Quantitative study of luminescence optical tomography. Application to sources localisation in molecular imaging

    International Nuclear Information System (INIS)

    Boffety, Matthieu

    2010-01-01

    Molecular imaging is a major modality in the field of preclinical research. Among the existing methods, techniques based on optical detection of visible or near infrared radiation are the most recent and are mainly represented by luminescence optical tomography techniques. These methods allow for 3D characterization of a biological medium by reconstructing maps of concentration or localisation of luminescent beacons sensitive to biological and chemical processes at the molecular or cellular scale. Luminescence optical tomography is based on a model of light propagation in tissues, a protocol for acquiring surface signal and a numerical inversion procedure used to reconstruct the parameters of interest. This thesis is structured around these three axes and provides an answer to each problem. The main objective of this study is to introduce and present the tools to evaluate the theoretical performances of optical tomography methods. One of its major outcomes is the realisation of experimental tomographic reconstructions from images acquired by an optical imager designed for 2D planar imaging and developed by the company Quidd. In a first step we develop the theory of transport in scattering medium to establish the concept on which our work will rely. We present two different propagation models as well as resolution methods and theoretical difficulties associated with them. In a second part we introduce the statistical tools used to characterise tomographic systems. We define and apply a procedure to simple situations in luminescence optical tomography. The last part of this work presents the development of an inversion procedure. After introducing the theoretical framework we validate the procedure from numerical data before successfully applying it to experimental measurements. (author) [fr

  2. Quantitative Assessment of Cervical Vertebral Maturation Using Cone Beam Computed Tomography in Korean Girls

    OpenAIRE

    Byun, Bo-Ram; Kim, Yong-Il; Yamaguchi, Tetsutaro; Maki, Koutaro; Son, Woo-Sung

    2015-01-01

    This study was aimed to examine the correlation between skeletal maturation status and parameters from the odontoid process/body of the second vertebra and the bodies of third and fourth cervical vertebrae and simultaneously build multiple regression models to be able to estimate skeletal maturation status in Korean girls. Hand-wrist radiographs and cone beam computed tomography (CBCT) images were obtained from 74 Korean girls (6?18 years of age). CBCT-generated cervical vertebral maturation ...

  3. A methodology for finding the optimal iteration number of the SIRT algorithm for quantitative Electron Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Okariz, Ana, E-mail: ana.okariz@ehu.es [eMERG, Fisika Aplikatua I Saila, Faculty of Engineering, University of the Basque Country, UPV/EHU, Rafael Moreno “Pitxitxi” Pasealekua 3, 48013 Bilbao (Spain); Guraya, Teresa [eMERG, Departamento de Ingeniería Minera y Metalúrgica y Ciencia de los Materiales, Faculty of Engineering, University of the Basque Country, UPV/EHU, Rafael Moreno “Pitxitxi” Pasealekua 3, 48013 Bilbao (Spain); Iturrondobeitia, Maider [eMERG, Departamento de Expresión Gráfica y Proyectos de Ingeniería, Faculty of Engineering, University of the Basque Country, UPV/EHU, Rafael Moreno “Pitxitxi” Pasealekua 3, 48013 Bilbao (Spain); Ibarretxe, Julen [eMERG, Fisika Aplikatua I Saila, Faculty of Engineering,University of the Basque Country, UPV/EHU, Rafael Moreno “Pitxitxi” Pasealekua 2, 48013 Bilbao (Spain)

    2017-02-15

    The SIRT (Simultaneous Iterative Reconstruction Technique) algorithm is commonly used in Electron Tomography to calculate the original volume of the sample from noisy images, but the results provided by this iterative procedure are strongly dependent on the specific implementation of the algorithm, as well as on the number of iterations employed for the reconstruction. In this work, a methodology for selecting the iteration number of the SIRT reconstruction that provides the most accurate segmentation is proposed. The methodology is based on the statistical analysis of the intensity profiles at the edge of the objects in the reconstructed volume. A phantom which resembles a a carbon black aggregate has been created to validate the methodology and the SIRT implementations of two free software packages (TOMOJ and TOMO3D) have been used. - Highlights: • The non uniformity of the resolution in electron tomography reconstructions has been demonstrated. • An overall resolution for the evaluation of the quality of electron tomography reconstructions has been defined. • Parameters for estimating an overall resolution across the reconstructed volume have been proposed. • The overall resolution of the reconstructions of a phantom has been estimated from the probability density functions. • It has been proven that reconstructions with the best overall resolutions have provided the most accurate segmentations.

  4. A methodology for finding the optimal iteration number of the SIRT algorithm for quantitative Electron Tomography

    International Nuclear Information System (INIS)

    Okariz, Ana; Guraya, Teresa; Iturrondobeitia, Maider; Ibarretxe, Julen

    2017-01-01

    The SIRT (Simultaneous Iterative Reconstruction Technique) algorithm is commonly used in Electron Tomography to calculate the original volume of the sample from noisy images, but the results provided by this iterative procedure are strongly dependent on the specific implementation of the algorithm, as well as on the number of iterations employed for the reconstruction. In this work, a methodology for selecting the iteration number of the SIRT reconstruction that provides the most accurate segmentation is proposed. The methodology is based on the statistical analysis of the intensity profiles at the edge of the objects in the reconstructed volume. A phantom which resembles a a carbon black aggregate has been created to validate the methodology and the SIRT implementations of two free software packages (TOMOJ and TOMO3D) have been used. - Highlights: • The non uniformity of the resolution in electron tomography reconstructions has been demonstrated. • An overall resolution for the evaluation of the quality of electron tomography reconstructions has been defined. • Parameters for estimating an overall resolution across the reconstructed volume have been proposed. • The overall resolution of the reconstructions of a phantom has been estimated from the probability density functions. • It has been proven that reconstructions with the best overall resolutions have provided the most accurate segmentations.

  5. Tomography

    International Nuclear Information System (INIS)

    Brown, B.H.; Barber, D.C.; Freeston, I.L.

    1983-01-01

    Tomography images of a body are constructed by placing a plurality of surface electrodes at spaced intervals on the body, causing currents to flow in the body (e.g. by applying a potential between each pair of electrodes in turn, or by induction), and measuring the potential between pairs of electrodes, calculating the potential expected in each case on the assumption that the body consists of a medium of uniform impedance, plotting the isopotentials corresponding to the calculated results to create a uniform image of the body, obtaining the ratio between the measured potential and the calculated potential in each case, and modifying the image in accordance with the respective ratios by increasing the assumed impedance along an isopotential in proportion to a ratio greater than unity or decreasing the assumed impedance in proportion to a ratio less than unity. The modified impedances along the isopotentials for each pair of electrodes are superimposed. The calculations are carried out using a computer and the plotting is carried out by a visual display unit and/or a print-out unit. (author)

  6. Quantitative study of undersampled recoverability for sparse images in computed tomography

    DEFF Research Database (Denmark)

    Jørgensen, Jakob Heide; Sidky, Emil Y.; Hansen, Per Christian

    2012-01-01

    on artificial random sampling patterns. We establish quantitatively an average-case relation between image sparsity and sufficient number of measurements for recovery, and we show that the transition from non-recovery to recovery is sharp within well-defined classes of simple and semi-realistic test images....... The specific behavior depends on the type of image, but the same quantitative relation holds independently of image size....

  7. The value of quantitative gallium-67 single-photon emission tomography in the clinical management of malignant external otitis

    International Nuclear Information System (INIS)

    Stokkel, M.P.M.; Eck-Smit, B.L.F. van; Takes, R.P.; Baatenburg de Jong, R.J.

    1997-01-01

    The objective of this study was to establish whether quantitative gallium-67 single-photon emission tomography (SPET) represents an accurate method for the assessment of infection and, moreover, for the monitoring of therapeutic effect. Eight patients (five males, three females) with the clinical diagnosis of MEO were studied. In three patients antibiotic treatment was prolonged for several weeks because visual analysis of gallium scintigraphy still showed slightly increased uptake in the affected area on the first follow-up scan. In one patient, it was decided to stop antibiotic treatment despite a slight increase in uptake on the second follow-up scan. Lesion to non-lesion (L/NL) ratios obtained from 67 Ga SPET images at initial diagnosis and during follow-up were assessed in correlation with clinical and biochemical data and with the results of CT scans. In addition to a raised erythrocyte sedimentation rate (ESR), all patients showed increased uptake on the affected side, with L/NL ratios ranging from 1.4 to 3.6 at the time of diagnosis. CT scans failed to demonstrate abnormalities in four patients. Including four scans demonstrating slightly increased uptake in the affected area, L/NL ratios after 6-8 weeks of antibiotic treatment were 1.0±0.1. Despite a persistently elevated ESR in the majority of patients, none of them demonstrated local recurrence or complications during follow-up. In all patients, leucocyte count was within the normal range throughout the course. No relation was found between the slightly increased uptake on the follow-up scans and surgical treatment. It is concluded that in addition to the visual analysis of 67 Ga SPET imaging, L/NL ratios should be calculated for a more accurate assessment of disease activity in MEO. Despite visually slightly increased uptake, L/NL ratios of 1.0±0.1 during follow-up are highly indicative of complete recovery, regardless of ESR values or leucocytosis. CT scans are of little value for diagnosis or for

  8. The value of quantitative gallium-67 single-photon emission tomography in the clinical management of malignant external otitis

    Energy Technology Data Exchange (ETDEWEB)

    Stokkel, M.P.M.; Eck-Smit, B.L.F. van [Department of Nuclear Medicine and Diagnostic Radiology, Leiden University Hospital (Netherlands); Takes, R.P.; Baatenburg de Jong, R.J. [Department of Otorhinolaryngology and Head and Neck Surgery, Leiden University Hospital (Netherlands)

    1997-11-01

    The objective of this study was to establish whether quantitative gallium-67 single-photon emission tomography (SPET) represents an accurate method for the assessment of infection and, moreover, for the monitoring of therapeutic effect. Eight patients (five males, three females) with the clinical diagnosis of MEO were studied. In three patients antibiotic treatment was prolonged for several weeks because visual analysis of gallium scintigraphy still showed slightly increased uptake in the affected area on the first follow-up scan. In one patient, it was decided to stop antibiotic treatment despite a slight increase in uptake on the second follow-up scan. Lesion to non-lesion (L/NL) ratios obtained from {sup 67}Ga SPET images at initial diagnosis and during follow-up were assessed in correlation with clinical and biochemical data and with the results of CT scans. In addition to a raised erythrocyte sedimentation rate (ESR), all patients showed increased uptake on the affected side, with L/NL ratios ranging from 1.4 to 3.6 at the time of diagnosis. CT scans failed to demonstrate abnormalities in four patients. Including four scans demonstrating slightly increased uptake in the affected area, L/NL ratios after 6-8 weeks of antibiotic treatment were 1.0{+-}0.1. Despite a persistently elevated ESR in the majority of patients, none of them demonstrated local recurrence or complications during follow-up. In all patients, leucocyte count was within the normal range throughout the course. No relation was found between the slightly increased uptake on the follow-up scans and surgical treatment. It is concluded that in addition to the visual analysis of {sup 67}Ga SPET imaging, L/NL ratios should be calculated for a more accurate assessment of disease activity in MEO. Despite visually slightly increased uptake, L/NL ratios of 1.0{+-}0.1 during follow-up are highly indicative of complete recovery, regardless of ESR values or leucocytosis. CT scans are of little value for

  9. Non-small cell lung cancer: Spectral computed tomography quantitative parameters for preoperative diagnosis of metastatic lymph nodes

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Fengfeng [Department of Radiology, The Fourth Affiliated Hospital, Harbin Medical University, Harbin 150001 (China); Dong, Jie [Department of Geriatrics, The First Affiliated Hospital, Harbin Medical University, Harbin 150001 (China); Wang, Xiuting; Fu, Xiaojiao [Department of Radiology, The Fourth Affiliated Hospital, Harbin Medical University, Harbin 150001 (China); Zhang, Tong, E-mail: zt415@sina.com [Department of Radiology, The Fourth Affiliated Hospital, Harbin Medical University, Harbin 150001 (China)

    2017-04-15

    Objective: To investigate the application value of spectral computed tomography (CT)quantitative parameters for preoperative diagnosis of metastatic lymph nodes in patients with non-small cell lung cancer (NSLC). Methods: 84 patients with suspected lung cancer who underwent chest dual-phase enhanced scan with gemstone spectral CT imaging (GSI) mode were selected. GSI quantitative parameters including normalized iodine concentrations (NIC), water concentration, slope of the spectral Hounsfield unit curve (λHU) were measured. The two-sample t test was used to statistically compare these quantitative parameters. Receiver operating characteristic (ROC) curves were drawn to establish the optimal threshold values. Results: A total of 144 lymph nodes were included, with 48 metastatic lymph nodes and 96 non-metastatic lymph nodes. The slope of the spectral Hounsfeld unit curve (λHU) measured during both arterial and venous phases were signifcantly higher in metastatic than in benign lymph nodes (P < 0.05). The area under the ROC curve (AUC = 0.951) of λHU of the arterial phase (AP) was the largest. When the optimal threshold values of λHU was 2.75, the sensitivity, specificity, and overall accuracy in the diagnosis of metastatic lymph nodes were 88.2%, 88.4%, 87.0%, respectively. Conclusion: Conventional CT diagnostic criteria established in accordance with size (lymph node maximal short axis diameter ≥10 mm) as the basis for judging metastatic lymph node. In quantitative assessment using spectral CT imaging, quantitative parameters showed higher accuracy than qualitative assessment of conventional CT based on the size for preoperative diagnosis of metastatic lymph nodes.

  10. Analysis of multiple scattering effects in optical Doppler tomography

    DEFF Research Database (Denmark)

    Yura, H.T.; Thrane, L.; Andersen, Peter E.

    2005-01-01

    Optical Doppler tomography (ODT) combines Doppler velocimetry and optical coherence tomography (OCT) to obtain high-resolution cross-sectional imaging of particle flow velocity in scattering media such as the human retina and skin. Here, we present the results of a theoretical analysis of ODT where...... multiple scattering effects are included. The purpose of this analysis is to determine how multiple scattering affects the estimation of the depth-resolved localized flow velocity. Depth-resolved velocity estimates are obtained directly from the corresponding mean or standard deviation of the observed...

  11. Quantitative analysis of scaling error compensation methods in dimensional X-ray computed tomography

    DEFF Research Database (Denmark)

    Müller, P.; Hiller, Jochen; Dai, Y.

    2015-01-01

    X-ray Computed Tomography (CT) has become an important technology for quality control of industrial components. As with other technologies, e.g., tactile coordinate measurements or optical measurements, CT is influenced by numerous quantities which may have negative impact on the accuracy...... errors of the manipulator system (magnification axis). This article also introduces a new compensation method for scaling errors using a database of reference scaling factors and discusses its advantages and disadvantages. In total, three methods for the correction of scaling errors – using the CT ball...

  12. Automatic quantitative micro-computed tomography evaluation of angiogenesis in an axially vascularized tissue-engineered bone construct.

    Science.gov (United States)

    Arkudas, Andreas; Beier, Justus Patrick; Pryymachuk, Galyna; Hoereth, Tobias; Bleiziffer, Oliver; Polykandriotis, Elias; Hess, Andreas; Gulle, Heinz; Horch, Raymund E; Kneser, Ulrich

    2010-12-01

    We invented an automatic observer-independent quantitative method to analyze vascularization using micro-computed tomography (CT) along with three-dimensional (3D) reconstruction in a tissue engineering model. An arteriovenous loop was created in the medial thigh of 30 rats and was placed in a particulated porous hydroxyapatite and beta-tricalcium phosphate matrix, filled with fibrin (10 mg/mL fibrinogen and 2 IU/mL thrombin) without (group A) or with (group B) application of fibrin-gel-immobilized angiogenetic growth factors vascular endothelial growth factor (VEGF¹⁶⁵) and basic fibroblast growth factor (bFGF). The explantation intervals were 2, 4, and 8 weeks. Specimens were investigated by means of micro-CT followed by an automatic 3D analysis, which was correlated to histomorphometrical findings. In both groups, the arteriovenous loop led to generation of dense vascularized connective tissue with differentiated and functional vessels inside the matrix. Quantitative analysis of vascularization using micro-CT showed to be superior to histological analysis. The micro-CT analysis also allows the assessment of different other, more complex vascularization parameters within 3D constructs, demonstrating an early improvement of vascularization by application of fibrin-gel-immobilized VEGF¹⁶⁵ and bFGF. In this study quantitative analysis of vascularization using micro-CT along with 3D reconstruction and automatic analysis exhibit to be a powerful method superior to histological evaluation of cross sections.

  13. Quantitative analysis and prediction of regional lymph node status in rectal cancer based on computed tomography imaging

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Chunyan; Liu, Lizhi; Li, Li [Sun Yat-sen University, State Key Laboratory of Oncology in Southern China, Imaging Diagnosis and Interventional Center, Cancer Center, Guangzhou, Guangdong (China); Cai, Hongmin; Tian, Haiying [Sun Yat-Sen University, Department of Automation, School of Science Information and Technology, Guangzhou (China); Li, Liren [Sun Yat-sen University, State Key Laboratory of Oncology in Southern China, Department of Abdominal (colon and rectal) Surgery, Cancer Center, Guangzhou (China)

    2011-11-15

    To quantitatively evaluate regional lymph nodes in rectal cancer patients by using an automated, computer-aided approach, and to assess the accuracy of this approach in differentiating benign and malignant lymph nodes. Patients (228) with newly diagnosed rectal cancer, confirmed by biopsy, underwent enhanced computed tomography (CT). Patients were assigned to the benign node or malignant node group according to histopathological analysis of node samples. All CT-detected lymph nodes were segmented using the edge detection method, and seven quantitative parameters of each node were measured. To increase the prediction accuracy, a hierarchical model combining the merits of the support and relevance vector machines was proposed to achieve higher performance. Of the 220 lymph nodes evaluated, 125 were positive and 95 were negative for metastases. Fractal dimension obtained by the Minkowski box-counting approach was higher in malignant nodes than in benign nodes, and there was a significant difference in heterogeneity between metastatic and non-metastatic lymph nodes. The overall performance of the proposed model is shown to have accuracy as high as 88% using morphological characterisation of lymph nodes. Computer-aided quantitative analysis can improve the prediction of node status in rectal cancer. (orig.)

  14. Impact of point spread function correction in standardized uptake value quantitation for positron emission tomography images. A study based on phantom experiments and clinical images

    International Nuclear Information System (INIS)

    Nakamura, Akihiro; Tanizaki, Yasuo; Takeuchi, Miho

    2014-01-01

    While point spread function (PSF)-based positron emission tomography (PET) reconstruction effectively improves the spatial resolution and image quality of PET, it may damage its quantitative properties by producing edge artifacts, or Gibbs artifacts, which appear to cause overestimation of regional radioactivity concentration. In this report, we investigated how edge artifacts produce negative effects on the quantitative properties of PET. Experiments with a National Electrical Manufacturers Association (NEMA) phantom, containing radioactive spheres of a variety of sizes and background filled with cold air or water, or radioactive solutions, showed that profiles modified by edge artifacts were reproducible regardless of background μ values, and the effects of edge artifacts increased with increasing sphere-to-background radioactivity concentration ratio (S/B ratio). Profiles were also affected by edge artifacts in complex fashion in response to variable combinations of sphere sizes and S/B ratios; and central single-peak overestimation up to 50% was occasionally noted in relatively small spheres with high S/B ratios. Effects of edge artifacts were obscured in spheres with low S/B ratios. In patient images with a variety of focal lesions, areas of higher radioactivity accumulation were generally more enhanced by edge artifacts, but the effects were variable depending on the size of and accumulation in the lesion. PET images generated using PSF-based reconstruction are therefore not appropriate for the evaluation of SUV. (author)

  15. [Impact of point spread function correction in standardized uptake value quantitation for positron emission tomography images: a study based on phantom experiments and clinical images].

    Science.gov (United States)

    Nakamura, Akihiro; Tanizaki, Yasuo; Takeuchi, Miho; Ito, Shigeru; Sano, Yoshitaka; Sato, Mayumi; Kanno, Toshihiko; Okada, Hiroyuki; Torizuka, Tatsuo; Nishizawa, Sadahiko

    2014-06-01

    While point spread function (PSF)-based positron emission tomography (PET) reconstruction effectively improves the spatial resolution and image quality of PET, it may damage its quantitative properties by producing edge artifacts, or Gibbs artifacts, which appear to cause overestimation of regional radioactivity concentration. In this report, we investigated how edge artifacts produce negative effects on the quantitative properties of PET. Experiments with a National Electrical Manufacturers Association (NEMA) phantom, containing radioactive spheres of a variety of sizes and background filled with cold air or water, or radioactive solutions, showed that profiles modified by edge artifacts were reproducible regardless of background μ values, and the effects of edge artifacts increased with increasing sphere-to-background radioactivity concentration ratio (S/B ratio). Profiles were also affected by edge artifacts in complex fashion in response to variable combinations of sphere sizes and S/B ratios; and central single-peak overestimation up to 50% was occasionally noted in relatively small spheres with high S/B ratios. Effects of edge artifacts were obscured in spheres with low S/B ratios. In patient images with a variety of focal lesions, areas of higher radioactivity accumulation were generally more enhanced by edge artifacts, but the effects were variable depending on the size of and accumulation in the lesion. PET images generated using PSF-based reconstruction are therefore not appropriate for the evaluation of SUV.

  16. Cost-effectiveness of PET and PET/Computed Tomography

    DEFF Research Database (Denmark)

    Gerke, Oke; Hermansson, Ronnie; Hess, Søren

    2015-01-01

    measure by means of incremental cost-effectiveness ratios when considering the replacement of the standard regimen by a new diagnostic procedure. This article discusses economic assessments of PET and PET/computed tomography reported until mid-July 2014. Forty-seven studies on cancer and noncancer...

  17. A novel 3D absorption correction method for quantitative EDX-STEM tomography

    International Nuclear Information System (INIS)

    Burdet, Pierre; Saghi, Z.; Filippin, A.N.; Borrás, A.; Midgley, P.A.

    2016-01-01

    This paper presents a novel 3D method to correct for absorption in energy dispersive X-ray (EDX) microanalysis of heterogeneous samples of unknown structure and composition. By using STEM-based tomography coupled with EDX, an initial 3D reconstruction is used to extract the location of generated X-rays as well as the X-ray path through the sample to the surface. The absorption correction needed to retrieve the generated X-ray intensity is then calculated voxel-by-voxel estimating the different compositions encountered by the X-ray. The method is applied to a core/shell nanowire containing carbon and oxygen, two elements generating highly absorbed low energy X-rays. Absorption is shown to cause major reconstruction artefacts, in the form of an incomplete recovery of the oxide and an erroneous presence of carbon in the shell. By applying the correction method, these artefacts are greatly reduced. The accuracy of the method is assessed using reference X-ray lines with low absorption. - Highlights: • A novel 3D absorption correction method is proposed for 3D EDX-STEM tomography. • The absorption of X-rays along the path to the surface is calculated voxel-by-voxel. • The method is applied on highly absorbed X-rays emitted from a core/shell nanowire. • Absorption is shown to cause major artefacts in the reconstruction. • Using the absorption correction method, the reconstruction artefacts are greatly reduced.

  18. A novel 3D absorption correction method for quantitative EDX-STEM tomography

    Energy Technology Data Exchange (ETDEWEB)

    Burdet, Pierre, E-mail: pierre.burdet@a3.epfl.ch [Department of Materials Science and Metallurgy, University of Cambridge, Charles Babbage Road 27, Cambridge CB3 0FS, Cambridgeshire (United Kingdom); Saghi, Z. [Department of Materials Science and Metallurgy, University of Cambridge, Charles Babbage Road 27, Cambridge CB3 0FS, Cambridgeshire (United Kingdom); Filippin, A.N.; Borrás, A. [Nanotechnology on Surfaces Laboratory, Materials Science Institute of Seville (ICMS), CSIC-University of Seville, C/ Americo Vespucio 49, 41092 Seville (Spain); Midgley, P.A. [Department of Materials Science and Metallurgy, University of Cambridge, Charles Babbage Road 27, Cambridge CB3 0FS, Cambridgeshire (United Kingdom)

    2016-01-15

    This paper presents a novel 3D method to correct for absorption in energy dispersive X-ray (EDX) microanalysis of heterogeneous samples of unknown structure and composition. By using STEM-based tomography coupled with EDX, an initial 3D reconstruction is used to extract the location of generated X-rays as well as the X-ray path through the sample to the surface. The absorption correction needed to retrieve the generated X-ray intensity is then calculated voxel-by-voxel estimating the different compositions encountered by the X-ray. The method is applied to a core/shell nanowire containing carbon and oxygen, two elements generating highly absorbed low energy X-rays. Absorption is shown to cause major reconstruction artefacts, in the form of an incomplete recovery of the oxide and an erroneous presence of carbon in the shell. By applying the correction method, these artefacts are greatly reduced. The accuracy of the method is assessed using reference X-ray lines with low absorption. - Highlights: • A novel 3D absorption correction method is proposed for 3D EDX-STEM tomography. • The absorption of X-rays along the path to the surface is calculated voxel-by-voxel. • The method is applied on highly absorbed X-rays emitted from a core/shell nanowire. • Absorption is shown to cause major artefacts in the reconstruction. • Using the absorption correction method, the reconstruction artefacts are greatly reduced.

  19. Quantitative analysis of computed tomography images and early detection of cerebral edema for pediatric traumatic brain injury patients: retrospective study

    OpenAIRE

    Kim, Hakseung; Kim, Gwang-dong; Yoon, Byung C; Kim, Keewon; Kim, Byung-Jo; Choi, Young Hun; Czosnyka, Marek; Oh, Byung-Mo; Kim, Dong-Joo

    2014-01-01

    Background The purpose of this study was to identify whether the distribution of Hounsfield Unit (HU) values across the intracranial area in computed tomography (CT) images can be used as an effective diagnostic tool for determining the severity of cerebral edema in pediatric traumatic brain injury (TBI) patients. Methods CT images, medical records and radiology reports on 70 pediatric patients were collected. Based on radiology reports and the Marshall classification, the patients were group...

  20. In vivo classification of human skin burns using machine learning and quantitative features captured by optical coherence tomography

    Science.gov (United States)

    Singla, Neeru; Srivastava, Vishal; Singh Mehta, Dalip

    2018-02-01

    We report the first fully automated detection of human skin burn injuries in vivo, with the goal of automatic surgical margin assessment based on optical coherence tomography (OCT) images. Our proposed automated procedure entails building a machine-learning-based classifier by extracting quantitative features from normal and burn tissue images recorded by OCT. In this study, 56 samples (28 normal, 28 burned) were imaged by OCT and eight features were extracted. A linear model classifier was trained using 34 samples and 22 samples were used to test the model. Sensitivity of 91.6% and specificity of 90% were obtained. Our results demonstrate the capability of a computer-aided technique for accurately and automatically identifying burn tissue resection margins during surgical treatment.

  1. Quantitative Analysis of Micro-Structure in Meat Emulsions from Grating-Based Multimodal X-Ray Tomography

    DEFF Research Database (Denmark)

    Einarsdottir, Hildur; Nielsen, Mikkel Schou; Miklos, Rikke

    2013-01-01

    Using novel X-ray techniques, based on grating-interferometry, new imaging modalities can be obtained simultaneously with absorption computed tomography (CT). These modalities, called phase contrast and dark field imaging, measure the electron density and the diffusion length of the sample....... Enhanced contrast capabilities of this X-ray technique makes studies on materials with similar attenuation properties possible. In this paper the focus is set on processing grating-based X-ray tomograms of meat emulsions to quantitatively measure micro-structural changes due to heat treatment. The emulsion...... samples were imaged both in a raw and cooked state. Additionally, different fat types were used in the emulsions in order to compare micro-structural differences when either pork fat or sunflower oil was used. From the reconstructed tomograms the different ingredients in the emulsions were segmented using...

  2. Quantitative characterization of near-field fuel sprays by multi-orifice direct injection using ultrafast x-tomography technique

    International Nuclear Information System (INIS)

    Liu, X.; Im, K.S.; Wang, Y.; Wang, J.; Hung, D.L.S.; Winkelman, J.R.; Tate, M.W.; Ercan, A.; Koerner, L.J.; Caswell, T.; Chamberlain, D.; Schuette, D.R.; Philipp, H.; Smilgies, D.M.; Gruner, S.M.

    2006-01-01

    A low-pressure direct injection fuel system for spark ignition direct injection engines has been developed, in which a high-turbulence nozzle technology was employed to achieve fine fuel droplet size at a low injection pressure around 2 MPa. It is particularly important to study spray characteristics in the near-nozzle region due to the immediate liquid breakup at the nozzle exit. By using an ultrafast x-ray area detector and intense synchrotron x-ray beams, the interior structure and dynamics of the direct injection gasoline sprays from a multi-orifice turbulence-assisted nozzle were elucidated for the first time in a highly quantitative manner with μs-temporal resolution. Revealed by a newly developed, ultrafast computed x-microtomography technique, many detailed features associated with the transient liquid flows are readily observable in the reconstructed spray. Furthermore, an accurate 3-dimensional fuel density distribution, in the form of fuel volume fraction, was obtained by the time-resolved computed tomography. The time-dependent fuel density distribution revealed that the fuel jet is well broken up immediately at the nozzle exits. These results not only reveal the near-field characteristics of the partial atomized fuel sprays with unprecedented detail, but also facilitate the development of an advanced multi-orifice direct injector. This ultrafast tomography capability also will facilitate the realistic computational fluid dynamic simulations in highly transient and multiphase fuel spray systems.

  3. Quantitative computed tomography for objectifying disseminated skeletal muscles alterations in female conductors of progressive muscular dystrophy

    International Nuclear Information System (INIS)

    Huppert, P.

    1987-01-01

    The detection of early morphologic changes, such as circumscribed infiltrations of adipose connective tissue into the muscles of female conductors of progressive muscular dystrophy requires quantitative planimetric methods. For a reliable interpretation of the results the dependence of the fat content of the musculature on age and physical constitution of the patient must be taken into consideration in each individual case. (author)

  4. Quantitative Computed Tomography Ventriculography for Assessment and Monitoring of Hydrocephalus: A Pilot Study and Description of Method in Subarachnoid Hemorrhage.

    Science.gov (United States)

    Multani, Jasjit Singh; Oermann, Eric Karl; Titano, Joseph; Mascitelli, Justin; Nicol, Kelly; Feng, Rui; Skovrlj, Branko; Pain, Margaret; Mocco, J D; Bederson, Joshua B; Costa, Anthony; Shrivastava, Raj

    2017-08-01

    There is no facile quantitative method for monitoring hydrocephalus (HCP). We propose quantitative computed tomography (CT) ventriculography (qCTV) as a novel computer vision tool for empirically assessing HCP in patients with subarachnoid hemorrhage (SAH). Twenty patients with SAH who were evaluated for ventriculoperitoneal shunt (VPS) placement were selected for inclusion. Ten patients with normal head computed tomography (CTH) findings were analyzed as negative controls. CTH scans were segmented both manually and automatically (by qCTV) to generate measures of ventricular volume. The median manually calculated ventricular volume was 36.1 cm 3 (interquartile range [IQR], 30-115 cm 3 ), which was similar to the median qCTV measured volume of 37.5 cm 3 (IQR, 32-118 cm 3 ) (P = 0.796). Patients undergoing VPS placement demonstrated an increase in median ventricular volume on qCTV from 21 cm 3 to 40 cm 3 on day T-2 and to 51 cm 3 by day 0, a change of 144%. This is in contrast to patients who did not require shunting, in whom median ventricular volume decreased from 16 cm 3 to 14 cm 3 on day T-2 and to 13 cm 3 by day 0, with an average overall volume decrease 19% (P = 0.001). The average change in ventricular volume predicted which patients would require VPS placement, successfully identifying 7 of 10 patients (P = 0.004). Using an optimized cutoff of a change in ventricular volume of 2.5 cm 3 identified all patients who went on to require VPS placement (10 of 10; P = 0.011). qCTV is a reliable means of quantifying ventricular volume and hydrocephalus. This technique offers a new tool for monitoring neurosurgical patients for hydrocephalus, and may be beneficial for use in future research studies, as well as in the routine care of patients with hydrocephalus. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Clinical application of skeletal scintigraphy and quantitative computed tomography (QCT) to osteoarthritis of the knee

    International Nuclear Information System (INIS)

    Mori, Muneshige

    1989-01-01

    Skeletal scintigraphy and QCT were performed to determine changes of subchondral bone tissues in osteoarthritis of the knee and findings were compared with plain X-ray findings, knee pain and femoro-tibial angle. Results on blood pool study were especially related to pain. Results in delayed study using single photon emission computed tomography revealed hign uptake on the medial side of the femur and tibia parallel to plain X-ray and pain. The QCT value was slightly decreased as osteoarthritic changes progressed without a significant change. In addition, delayed study in cases with previous surgical intervention by high tibial osteotomy revealed a lower uptake on the medial side of the femur and tibia. When skeletal scintigraphy accurately reflects blood flow through the subchondral bone tissues and is closely related to morbidity and pain, this modality is valuable in analysis of signs and symptoms as well as postoperative outcome. (author)

  6. Computer-based quantitative computed tomography image analysis in idiopathic pulmonary fibrosis: A mini review.

    Science.gov (United States)

    Ohkubo, Hirotsugu; Nakagawa, Hiroaki; Niimi, Akio

    2018-01-01

    Idiopathic pulmonary fibrosis (IPF) is the most common type of progressive idiopathic interstitial pneumonia in adults. Many computer-based image analysis methods of chest computed tomography (CT) used in patients with IPF include the mean CT value of the whole lungs, density histogram analysis, density mask technique, and texture classification methods. Most of these methods offer good assessment of pulmonary functions, disease progression, and mortality. Each method has merits that can be used in clinical practice. One of the texture classification methods is reported to be superior to visual CT scoring by radiologist for correlation with pulmonary function and prediction of mortality. In this mini review, we summarize the current literature on computer-based CT image analysis of IPF and discuss its limitations and several future directions. Copyright © 2017 The Japanese Respiratory Society. Published by Elsevier B.V. All rights reserved.

  7. Quantitative evaluation of hip joint laxity in 22 Border Collies using computed tomography

    International Nuclear Information System (INIS)

    Kishimoto, M.; Yamada, K.; Pae, S.H.; Muroya, N.; Watarai, H.; Anzai, H.; Shimizu, J.; Iwasaki, T.; Miyake, Y.; Wisner, E.R.

    2009-01-01

    The purpose of this study was to obtain the computed tomography (CT) data for the hip joints of 22 Border Collies. The dorsolateral subluxation (DLS) score, lateral center edge angle (LCEA), dorsal acetabular rim angle (DARA) and center distance (CD) index were measured on the CT images in a weight-bearing position. Radiographic Norberg angle (NA) was also measured. The mean values were 45.7+-10.2% for DLS score, 85.9deg+-10.3deg for LCEA, 18.5deg+-7.3deg for DARA, 0.40+-0.17 for CD index and 102.7deg+-6.9deg for NA. Since the DLS score and LCEA showed strong correlation, combined use of these parameters might improve diagnostic accuracy. We consider CT evaluation in a weight-bearing position to be a useful method for multidirectional evaluation of hips

  8. Investigating the correlation between computerized tomography changes and quantitative consciousness disturbances in stroke patients

    International Nuclear Information System (INIS)

    Toneva, Yu.; Manchev, I.; Tsolova, M.

    1997-01-01

    One-hundred and nine patients undergo computerized tomographic (CT) and clinical investigations. The correlation between CT finding and quantitative consciousness disturbances has been studied. The somatic, neurologic and mental states are evaluated, and the changes in consciousness are classified according to a 4-degree rating system adopted in this country, namely: obnubilation, somnolence, sopor and coma. For the purpose a computerized tomograph CE 10000 is used. Cerebral infarctions in the right middle cerebral artery pool predominate. Here the disturbances are of a milder degree - obnubilation and somnolence. In stroke syndrome cases the states of sopor and coma are more frequent which may be explained with the rather severely manifested brain edema. In either form of cerebrovascular disease the quantitative disorders of consciousness are not dependent on the location of the accident in the dominant hemisphere. They are directly related to the CT documented size of pathological focus

  9. Validation of electrical impedance tomography qualitative and quantitative values and comparison of the numeric pain distress score against mammography.

    Science.gov (United States)

    Juliana, Norsham; Shahar, Suzana; Chelliah, Kanaga Kumari; Ghazali, Ahmad Rohi; Osman, Fazilah; Sahar, Mohd Azmani

    2014-01-01

    Electrical impedance tomography (EIT) is a potential supplement for mammogram screening. This study aimed to evaluate and feasibility of EIT as opposed to mammography and to determine pain perception with both imaging methods. Women undergoing screening mammography at the Radiology Department of National University of Malaysia Medical Centre were randomly selected for EIT imaging. All women were requested to give a pain score after each imaging session. Two independent raters were chosen to define the image findings of EIT. A total of 164 women in the age range from 40 to 65-year-old participated and were divided into two groups; normal and abnormal. EIT sensitivity and specificity for rater 1 were 69.4% and 63.3, whereas for rater 2 they were 55.3% and 57.0% respectively. The reliability for each rater ranged between good to very good (p<0.05). Quantitative values of EIT showed there were significant differences in all values between groups (ANCOVA, p<0.05). Interestingly, EIT scored a median pain score of 1.51±0.75 whereas mammography scored 4.15±0.87 (Mann Whitney U test, p<0.05). From these quantitative values, EIT has the potential as a health discriminating index. Its ability to replace image findings from mammography needs further investigation.

  10. Practical no-gold-standard evaluation framework for quantitative imaging methods: application to lesion segmentation in positron emission tomography.

    Science.gov (United States)

    Jha, Abhinav K; Mena, Esther; Caffo, Brian; Ashrafinia, Saeed; Rahmim, Arman; Frey, Eric; Subramaniam, Rathan M

    2017-01-01

    Recently, a class of no-gold-standard (NGS) techniques have been proposed to evaluate quantitative imaging methods using patient data. These techniques provide figures of merit (FoMs) quantifying the precision of the estimated quantitative value without requiring repeated measurements and without requiring a gold standard. However, applying these techniques to patient data presents several practical difficulties including assessing the underlying assumptions, accounting for patient-sampling-related uncertainty, and assessing the reliability of the estimated FoMs. To address these issues, we propose statistical tests that provide confidence in the underlying assumptions and in the reliability of the estimated FoMs. Furthermore, the NGS technique is integrated within a bootstrap-based methodology to account for patient-sampling-related uncertainty. The developed NGS framework was applied to evaluate four methods for segmenting lesions from F-Fluoro-2-deoxyglucose positron emission tomography images of patients with head-and-neck cancer on the task of precisely measuring the metabolic tumor volume. The NGS technique consistently predicted the same segmentation method as the most precise method. The proposed framework provided confidence in these results, even when gold-standard data were not available. The bootstrap-based methodology indicated improved performance of the NGS technique with larger numbers of patient studies, as was expected, and yielded consistent results as long as data from more than 80 lesions were available for the analysis.

  11. Use of computed tomography and automated software for quantitative analysis of the vasculature of patients with pulmonary hypertension

    Energy Technology Data Exchange (ETDEWEB)

    Wada, Danilo Tadao; Pádua, Adriana Ignácio de; Lima Filho, Moyses Oliveira; Marin Neto, José Antonio; Elias Júnior, Jorge; Baddini-Martinez, José; Santos, Marcel Koenigkam, E-mail: danilowada@yahoo.com.br [Universidade de São Paulo (HCFMRP/USP), Ribeirão Preto, SP (Brazil). Faculdade de Medicina. Hospital das Clínicas

    2017-11-15

    Objective: To perform a quantitative analysis of the lung parenchyma and pulmonary vasculature of patients with pulmonary hypertension (PH) on computed tomography angiography (CTA) images, using automated software. Materials And Methods: We retrospectively analyzed the CTA findings and clinical records of 45 patients with PH (17 males and 28 females), in comparison with a control group of 20 healthy individuals (7 males and 13 females); the mean age differed significantly between the two groups (53 ± 14.7 vs. 35 ± 9.6 years; p = 0.0001). Results: The automated analysis showed that, in comparison with the controls, the patients with PH showed lower 10{sup th} percentile values for lung density, higher vascular volumes in the right upper lung lobe, and higher vascular volume ratios between the upper and lower lobes. In our quantitative analysis, we found no differences among the various PH subgroups. We inferred that a difference in the 10{sup th} percentile values indicates areas of hypovolaemia in patients with PH and that a difference in pulmonary vascular volumes indicates redistribution of the pulmonary vasculature and an increase in pulmonary vasculature resistance. Conclusion: Automated analysis of pulmonary vessels on CTA images revealed alterations and could represent an objective diagnostic tool for the evaluation of patients with PH. (author)

  12. Quantitative computed tomography as a test of endurance for evaluation of bony plates; Utilizacao da tomografia computadorizada quantitativa como teste de resistencia para avaliacao de placas osseas

    Energy Technology Data Exchange (ETDEWEB)

    Melo Filho, E.V.; Costa, L.A.V.S.; Oliveira, D.C. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil); Freitas, P.M.C. [Escola de Veterinaria - Universidade Federal de Minas Gerais - Belo Horizonte, MG (Brazil); Teixeira, M.W.; Costa, F.S. [Universidade Federal Rural de Pernambuco - Recife, PE (Brazil)

    2012-06-15

    Quantitative computed tomography was used to determine the radiodensity of bony plates. The CT scans provided information regarding radiodensity of bony plates and allowed to verify the uniformity of bone mineral density in their scope. The proposed methodology should be considered as another tool for determining the resistance of these biomaterials. (author)

  13. Ab initio structure determination and quantitative disorder analysis on nanoparticles by electron diffraction tomography.

    Science.gov (United States)

    Krysiak, Yaşar; Barton, Bastian; Marler, Bernd; Neder, Reinhard B; Kolb, Ute

    2018-03-01

    Nanoscaled porous materials such as zeolites have attracted substantial attention in industry due to their catalytic activity, and their performance in sorption and separation processes. In order to understand the properties of such materials, current research focuses increasingly on the determination of structural features beyond the averaged crystal structure. Small particle sizes, various types of disorder and intergrown structures render the description of structures at atomic level by standard crystallographic methods difficult. This paper reports the characterization of a strongly disordered zeolite structure, using a combination of electron exit-wave reconstruction, automated diffraction tomography (ADT), crystal disorder modelling and electron diffraction simulations. Zeolite beta was chosen for a proof-of-principle study of the techniques, because it consists of two different intergrown polymorphs that are built from identical layer types but with different stacking sequences. Imaging of the projected inner Coulomb potential of zeolite beta crystals shows the intergrowth of the polymorphs BEA and BEB. The structures of BEA as well as BEB could be extracted from one single ADT data set using direct methods. A ratio for BEA/BEB = 48:52 was determined by comparison of the reconstructed reciprocal space based on ADT data with simulated electron diffraction data for virtual nanocrystals, built with different ratios of BEA/BEB. In this way, it is demonstrated that this smart interplay of the above-mentioned techniques allows the elaboration of the real structures of functional materials in detail - even if they possess a severely disordered structure.

  14. The quantitative measurements of foveal avascular zone using optical coherence tomography angiography in normal volunteers.

    Science.gov (United States)

    Ghassemi, Fariba; Mirshahi, Reza; Bazvand, Fatemeh; Fadakar, Kaveh; Faghihi, Houshang; Sabour, Siamak

    2017-12-01

    To provide normative data of foveal avascular zone (FAZ) and thickness. In this cross-sectional study both eyes of each normal subject were scanned with optical coherence tomography angiography (OCTA) for foveal superficial and deep avascular zone (FAZ) and central foveal thickness (CFT) and parafoveal thickness (PFT). Out of a total of 224 eyes of 112 volunteers with a mean age of 37.03 (12-67) years, the mean superficial FAZ area was 0.27 mm 2 , and deep FAZ area was 0.35 mm 2 ( P  < 0.001), with no difference between both eyes. Females had a larger superficial (0.32 ± 0.11 mm 2 versus 0.23 ± 0.09 mm 2 ) and deep FAZ (0.40 ± 0.14 mm 2 versus 0.31 ± 0.10 mm 2 ) ( P  < 0.001) than males. By multivariate linear regression analysis, in normal eyes, superficial FAZ area varied significantly with the gender, CFT, and deep FAZ. Deep FAZ varied with the gender and CFT. The gender and CFT influence the size of normal superficial and deep FAZ of capillary network.

  15. Computed tomography for the quantitative characterization of flow through a porous medium

    International Nuclear Information System (INIS)

    Auzerais, F.M.; Dussan, E.B.; Reischer, A.J.

    1991-01-01

    X-ray computer tomography (CT) has become an increasingly popular research tool in petroleum engineering for characterizing porous media. Its highly detailed images have been used to construct maps of porosity, saturation and atomic composition, and to visualize the displacement of fluids. However, extracting data necessary to characterize flow through porous media is both time consuming and dependent on the availability of extensive computational resources - - a consequence of the large size of the image files. The authors of this paper applied to known technique, based upon the ability to recognize regions with similar features, which avoids these difficulties. It allows the authors to substitute for the image, the pixel location of the boundaries of the recognized regions, reducing considerably the computer storage requirements. The authors this technique to study the dynamics of two miscible liquids of different densities flowing through a porous medium where buoyancy plays an important role. The authors' specific concern is the movement of mud filtrate as it penetrates a permeable formation in the vicinity of a recently drilled wellbore. The authors quantify the manner in which impermeable horizontal barriers influence the movement of the filtrate

  16. Quantification of mitral regurgitation on cardiac computed tomography: comparison with qualitative and quantitative echocardiographic parameters.

    LENUS (Irish Health Repository)

    Arnous, Samer

    2012-02-01

    PURPOSE: To assess whether cardiac computed tomographic angiography (CCTA) can quantify the severity of chronic mitral regurgitation (MR) compared to qualitative and quantitative echocardiographic parameters. MATERIALS AND METHODS: Cardiac computed tomographic angiography was performed in 23 patients (mean +\\/- SD age, 63 +\\/- 16 years; range, 24-86 years) with MR and 20 patients without MR (controls) as determined by transthoracic echocardiography. Multiphasic reconstructions (20 data sets reconstructed at 5% increments of the electrocardiographic gated R-R interval) were used to analyze the mitral valve. Using CCTA planimetry, 2 readers measured the regurgitant mitral orifice area (CCTA ROA) during systole. A qualitative echocardiographic assessment of severity of MR was made by visual assessment of the length of the regurgitant jet. Quantitative echocardiographic measurements included the vena contracta, proximal isovelocity surface area, regurgitant volume, and estimated regurgitant orifice (ERO). Comparisons were performed using the independent t test, and correlations were assessed using the Spearman rank test. RESULTS: All controls and the patients with MR were correctly identified by CCTA. For patients with mild, moderate, or severe MR, mean +\\/- SD EROs were 0.16 +\\/- 0.03, 0.31 +\\/- 0.08, and 0.52 +\\/- 0.03 cm(2) (P < 0.0001) compared with mean +\\/- SD CCTA ROAs 0.09 +\\/- 0.05, 0.30 +\\/- 0.04, and 0.97 +\\/- 0.26 cm(2) (P < 0.0001), respectively. When echocardiographic measurements were graded qualitatively as mild, moderate, or severe, strong correlations were seen with CCTA ROA (R = 0.89; P < 0.001). When echocardiographic measurements were graded quantitatively, the vena contracta and the ERO showed modest correlations with CCTA ROA (0.48 and 0.50; P < 0.05 for both). Neither the proximal isovelocity surface area nor the regurgitant volume demonstrated significant correlations with CCTA ROA. CONCLUSIONS: Single-source 64-slice CCTA provides a

  17. Quantitative evaluation of emphysematous changes in the lung by computed tomography (CT)

    International Nuclear Information System (INIS)

    Kitahara, Yoshinari; Hirayama, Takanobu; Hiratsuka, Toshihiko; Tanaka, Yasushi; Takamoto, Masahiro; Ishibashi, Tsuneo; Shinoda, Atsushi

    1987-01-01

    The present studies were undertaken to quantitatively evaluate emphysematous changes in the lung by CT scan. CT scans were made at inspiration and expiration at three levels (base, mid thorax and apex). Low density lesion ratio (LL %) was measured as the proportion of the area under -950 Housfield Unit in each lung field at expiration. Each value of LL % was determined in 6 lung fields (both lung fields at three levels). The LL % was calculated from the mean of these six values. The results suggest that LL % of the emphysematous lungs shows significant elevation of the values compared with those of normal lungs and lungs with bronchial asthma. (author)

  18. Bragg peak prediction from quantitative proton computed tomography using different path estimates

    International Nuclear Information System (INIS)

    Wang Dongxu; Mackie, T Rockwell; Tome, Wolfgang A

    2011-01-01

    This paper characterizes the performance of the straight-line path (SLP) and cubic spline path (CSP) as path estimates used in reconstruction of proton computed tomography (pCT). The GEANT4 Monte Carlo simulation toolkit is employed to simulate the imaging phantom and proton projections. SLP, CSP and the most-probable path (MPP) are constructed based on the entrance and exit information of each proton. The physical deviations of SLP, CSP and MPP from the real path are calculated. Using a conditional proton path probability map, the relative probability of SLP, CSP and MPP are calculated and compared. The depth dose and Bragg peak are predicted on the pCT images reconstructed using SLP, CSP, and MPP and compared with the simulation result. The root-mean-square physical deviations and the cumulative distribution of the physical deviations show that the performance of CSP is comparable to MPP while SLP is slightly inferior. About 90% of the SLP pixels and 99% of the CSP pixels lie in the 99% relative probability envelope of the MPP. Even at an imaging dose of ∼0.1 mGy the proton Bragg peak for a given incoming energy can be predicted on the pCT image reconstructed using SLP, CSP, or MPP with 1 mm accuracy. This study shows that SLP and CSP, like MPP, are adequate path estimates for pCT reconstruction, and therefore can be chosen as the path estimation method for pCT reconstruction, which can aid the treatment planning and range prediction of proton radiation therapy.

  19. Bragg peak prediction from quantitative proton computed tomography using different path estimates

    Energy Technology Data Exchange (ETDEWEB)

    Wang Dongxu; Mackie, T Rockwell; Tome, Wolfgang A, E-mail: tome@humonc.wisc.edu [Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705 (United States)

    2011-02-07

    This paper characterizes the performance of the straight-line path (SLP) and cubic spline path (CSP) as path estimates used in reconstruction of proton computed tomography (pCT). The GEANT4 Monte Carlo simulation toolkit is employed to simulate the imaging phantom and proton projections. SLP, CSP and the most-probable path (MPP) are constructed based on the entrance and exit information of each proton. The physical deviations of SLP, CSP and MPP from the real path are calculated. Using a conditional proton path probability map, the relative probability of SLP, CSP and MPP are calculated and compared. The depth dose and Bragg peak are predicted on the pCT images reconstructed using SLP, CSP, and MPP and compared with the simulation result. The root-mean-square physical deviations and the cumulative distribution of the physical deviations show that the performance of CSP is comparable to MPP while SLP is slightly inferior. About 90% of the SLP pixels and 99% of the CSP pixels lie in the 99% relative probability envelope of the MPP. Even at an imaging dose of {approx}0.1 mGy the proton Bragg peak for a given incoming energy can be predicted on the pCT image reconstructed using SLP, CSP, or MPP with 1 mm accuracy. This study shows that SLP and CSP, like MPP, are adequate path estimates for pCT reconstruction, and therefore can be chosen as the path estimation method for pCT reconstruction, which can aid the treatment planning and range prediction of proton radiation therapy.

  20. Bragg peak prediction from quantitative proton computed tomography using different path estimates

    Science.gov (United States)

    Wang, Dongxu; Mackie, T Rockwell

    2015-01-01

    This paper characterizes the performance of the straight-line path (SLP) and cubic spline path (CSP) as path estimates used in reconstruction of proton computed tomography (pCT). The GEANT4 Monte Carlo simulation toolkit is employed to simulate the imaging phantom and proton projections. SLP, CSP and the most-probable path (MPP) are constructed based on the entrance and exit information of each proton. The physical deviations of SLP, CSP and MPP from the real path are calculated. Using a conditional proton path probability map, the relative probability of SLP, CSP and MPP are calculated and compared. The depth dose and Bragg peak are predicted on the pCT images reconstructed using SLP, CSP, and MPP and compared with the simulation result. The root-mean-square physical deviations and the cumulative distribution of the physical deviations show that the performance of CSP is comparable to MPP while SLP is slightly inferior. About 90% of the SLP pixels and 99% of the CSP pixels lie in the 99% relative probability envelope of the MPP. Even at an imaging dose of ~0.1 mGy the proton Bragg peak for a given incoming energy can be predicted on the pCT image reconstructed using SLP, CSP, or MPP with 1 mm accuracy. This study shows that SLP and CSP, like MPP, are adequate path estimates for pCT reconstruction, and therefore can be chosen as the path estimation method for pCT reconstruction, which can aid the treatment planning and range prediction of proton radiation therapy. PMID:21212472

  1. COST EFFECTIVE AND HIGH RESOLUTION SUBSURFACE CHARACTERIZATION USING HYDRAULIC TOMOGRAPHY

    Science.gov (United States)

    2017-08-01

    objective of this project is to provide the DoD and its remediation contractors with the HT technology for delineating the spatial distribution of...STATEMENT Approved for public release; distribution is unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT Hydraulic Tomography ( HT ) is a high-resolution...performance of subsurface remedial actions at environmental sites. The good technical performance and cost-effectiveness of HT have been demonstrated in

  2. Quantitative reconstruction of PIXE-tomography data for thin samples using GUPIX X-ray emission yields

    Energy Technology Data Exchange (ETDEWEB)

    Michelet, C., E-mail: michelet@cenbg.in2p3.fr [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Barberet, Ph., E-mail: barberet@cenbg.in2p3.fr [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Devès, G., E-mail: deves@cenbg.in2p3.fr [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Bouguelmouna, B., E-mail: bbouguel@gmail.com [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Bourret, S., E-mail: bourret@cenbg.in2p3.fr [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Delville, M.-H., E-mail: delville@icmcb-bordeaux.cnrs.fr [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); Le Trequesser, Q., E-mail: letreque@cenbg.in2p3.fr [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); Gordillo, N., E-mail: nuri.gordillo@gmail.com [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Beasley, D.G., E-mail: d.beasley@ucl.ac.uk [Center of Medical Imaging Computing (CMIC), Department of Medical Physics & Bioengineering, University College London, Gower Street, London WC1E 6BT (United Kingdom); and others

    2015-04-01

    We present here a new development of the TomoRebuild software package, to perform quantitative Particle Induced X-ray Emission Tomography (PIXET) reconstruction. X-ray yields are obtained from the GUPIX code. The GUPIX data base is available for protons up to 5 MeV and also in the 20–100 MeV energy range, deuterons up to 6 MeV, {sup 3}He and alphas up to 12 MeV. In this version, X-ray yields are calculated for thin samples, i.e. without simulating X-ray attenuation. PIXET data reconstruction is kept as long as possible independent from Scanning Transmission Ion Microscopy Tomography (STIMT). In this way, the local mass distribution (in g/cm{sup 3}) of each X-ray emitting element is reconstructed in all voxels of the analyzed volume, only from PIXET data, without the need of associated STIMT data. Only the very last step of data analysis requires STIMT data, in order to normalize PIXET data to obtain concentration distributions, in terms of normalized mass fractions (in μg/g). For this, a noise correction procedure has been designed in ImageJ. Moreover sinogram or image misalignment can be corrected, as well as the difference in beam size between the two experiments. The main features of the TomoRebuild code, user friendly design and modular C++ implementation, were kept. The software package is portable and can run on Windows and Linux operating systems. An optional user-friendly graphic interface was designed in Java, as a plugin for the ImageJ graphic software package. Reconstruction examples are presented from biological specimens of Caenorhabditis elegans – a small nematode constituting a reference model for biology studies. The reconstruction results are compared between the different codes TomoRebuild, DISRA and JPIXET, and different reconstruction methods: Filtered BackProjection (FBP) and Maximum Likelihood Expectation Maximization (MLEM)

  3. Qualitative and quantitative interpretation of computed tomography of the lungs in healthy neonatal foals.

    Science.gov (United States)

    Lascola, Kara M; O'Brien, Robert T; Wilkins, Pamela A; Clark-Price, Stuart C; Hartman, Susan K; Mitchell, Mark A

    2013-09-01

    To qualitatively describe lung CT images obtained from sedated healthy equine neonates (≤ 14 days of age), use quantitative analysis of CT images to characterize attenuation and distribution of gas and tissue volumes within the lungs, and identify differences between lung characteristics of foals ≤ 7 days of age and foals > 7 days of age. 10 Standardbred foals between 2.5 and 13 days of age. Foals were sedated with butorphanol, midazolam, and propofol and positioned in sternal recumbency for thoracic CT. Image analysis software was used to exclude lung from nonlung structures. Lung attenuation was measured in Hounsfield units (HU) for analysis of whole lung and regional changes in attenuation and lung gas and tissue components. Degree of lung attenuation was classified as follows: hyperinflated or emphysema, -1,000 to -901 HU; well aerated, -900 to -501 HU; poorly aerated, -500 to -101 HU; and nonaerated, > -100 HU. Qualitative evidence of an increase in lung attenuation and patchy alveolar patterns in the ventral lung region were more pronounced in foals ≤ 7 days of age than in older foals. Quantitative analysis revealed that mean ± SD lung attenuation was greater in foals ≤ 7 days of age (-442 ± 28 HU) than in foals > 7 days of age (-521 ± 24 HU). Lung aeration and gas volumes were lower than in other regions ventrally and in the mid lung region caudal to the heart. CONCLUSIONS AND CLINICAL RELEVANCE-Identified radiographic patterns and changes in attenuation were most consistent with atelectasis and appeared more severe in foals ≤ 7 days of age than in older neonatal foals. Recognition of these changes may have implications for accurate CT interpretation in sedated neonatal foals with pulmonary disease.

  4. Optical coherence tomography based microangiography for quantitative monitoring of structural and vascular changes in a rat model of acute uveitis in vivo: a preliminary study

    Science.gov (United States)

    Choi, Woo June; Pepple, Kathryn L.; Zhi, Zhongwei; Wang, Ruikang K.

    2015-01-01

    Uveitis models in rodents are important in the investigation of pathogenesis in human uveitis and the development of appropriate therapeutic strategies for treatment. Quantitative monitoring of ocular inflammation in small animal models provides an objective metric to assess uveitis progression and/or therapeutic effects. We present a new application of optical coherence tomography (OCT) and OCT-based microangiography (OMAG) to a rat model of acute anterior uveitis induced by intravitreal injection of a killed mycobacterial extract. OCT/OMAG is used to provide noninvasive three-dimensional imaging of the anterior segment of the eyes prior to injection (baseline) and two days post-injection (peak inflammation) in rats with and without steroid treatments. OCT imaging identifies characteristic structural and vascular changes in the anterior segment of the inflamed animals when compared to baseline images. Characteristics of inflammation identified include anterior chamber cells, corneal edema, pupillary membranes, and iris vasodilation. In contrast, no significant difference from the control is observed for the steroid-treated eye. These findings are compared with the histology assessment of the same eyes. In addition, quantitative measurements of central corneal thickness and iris vessel diameter are determined. This pilot study demonstrates that OCT-based microangiography promises to be a useful tool for the assessment and management of uveitis in vivo.

  5. Development and evaluation of a method for quantitative flow measurement in tissues by means of NMR-tomography

    International Nuclear Information System (INIS)

    Meindl, S.; Seelen, W. von; Hoffmann, K.P.; Emmert, K.

    1985-01-01

    Apart from the known parameters proton density, T1 and T2 the amplitude of an NMR signal is influenced by the movement of the nuclear spins. In NMR-tomography this leads to significant flow-dependent effects appearing differently in the images. Basing on these influences well-defined flow measurement can be carried out using special tomographic measuring programs. The applied phase encoding methods allow such measurements parallel to conventional imaging. Changes in perfusion of defined brain areas caused by neuronal activity were examined with this technique as well as a 2F-2D-glucose-tracer method. (orig.) With 51 refs., 19 figs [de

  6. Optical Coherence Tomography for Quantitative Assessment of Microstructural and Microvascular Alterations in Late Oral Radiation Toxicity

    Science.gov (United States)

    Davoudi, Bahar

    More than half of head-and-neck cancer patients undergo radiotherapy at some point during their treatment. Even though the use of conformed therapeutic beams has increased radiation dose localization to the tumor, resulting in more normal tissue sparing, still, in many head-and-neck cancer patients, the healthy tissue of the oral cavity still receives a sizeable amount of radiation. This causes acute and / or late complications in these patients. The latter occur as late as several months or even years after the completion of treatment and are typically associated with severe symptoms. Currently, the clinical method for diagnosing these complications is visual examination of the oral tissue surface. However, it has been well established that such complications originate in subsurface oral tissue layers including its microvasculature. Therefore, to better understand the mechanism of these complications and to be able to diagnose them earlier, there exists a need for subsurface monitoring of the irradiated oral tissue. Histology has been used as such a tool for research purposes; however, its use in clinical diagnosis is limited due to its invasive and hazardous nature. Therefore, in this thesis, I propose to use optical coherence tomography (OCT) as a subsurface, micron-scale resolution optical imaging tool that can provide images of oral tissue subsurface layers down to a depth of 1-2 mm (structural OCT), as well as images demonstrating vessel morphology (speckle variance OCT) and blood flow information (Doppler OCT). This thesis explains the development of an OCT setup and an oral probe to acquire images in-vivo. Moreover, it introduces a software-based quantification platform for extracting specific biologically-meaningful metrics from the structural and vascular OCT images. It then describes the application of the developed imaging and quantification platform in a feasibility clinical study that was performed on 15 late oral radiation toxicity patients and 5 age

  7. Fringe effect of electrical capacitance and resistance tomography sensors

    International Nuclear Information System (INIS)

    Sun, Jiangtao; Yang, Wuqiang

    2013-01-01

    Because of the ‘soft-field’ nature, all electrical tomography sensors suffer from electric field distortion, i.e. the fringe effect. In electrical resistance tomography (ERT) sensors, small pin electrodes are commonly used. It is well known that the pin electrodes result in severe electric field distortion or the fringe effect, and the sensing region of such an ERT sensor spreads out of the pin electrode plane to a large volume. This is also true for electrical capacitance tomography (ECT) sensors, even though it is less severe because of larger electrodes and grounded end guards used. However, when the length of electrodes in an ECT sensor without guards is reduced to almost the same dimension as those in an ERT sensor, the fringe effect is equally obvious. To investigate the fringe effect of ERT and ECT sensors with and without guards, simulations were carried out with different length of electrodes and the results are compared with the corresponding 2D simulation. It is concluded that ECT and ERT sensors with longer electrodes have less fringe effect. Because grounded end guards are effective in reducing the fringe effect of ECT sensors, we propose to apply grounded guards in ERT sensors and integrate ECT and ERT sensors together. Simulation results reveal that ERT sensors with grounded guards have less fringe effect. While commonly current excitation is used with ERT sensors, we propose voltage excitation instead to apply the grounded guards. The feasibility of this approach has been verified by experiment. Finally, a common structure for reducing the fringe effect is proposed for ECT and ERT sensors for the first time to simplify the sensor structure and reduce the mutual interference in ECT/ERT dual-modality measurements. (paper)

  8. A quantitative approach of abdominal aortic atherosclerosis with x-ray computed tomography

    International Nuclear Information System (INIS)

    Watanabe, Hiromi; Kubota, Kazuo; Ito, Kengo; Ono, Shuichi; Matsuzawa, Taiju

    1983-01-01

    Currently epidemiologic studies of aortic atherosclerosis are most commonly done by the conventional roentgenological or pathological methods before and after death respectively. Pathological method is difficult and only possible after death. Roentgenological method is simple and useful before death, but its inability to evaluate atherosclerosis in a constant manner is serious drawback. A simple and quantitative method for epidemiological and clinical study of atherosclerosis has been needed. It this study, we examined the usefulness of Calcification Index (C.I.) caliculated from CT films for the evaluation of abdominal aortic atherosclerosis. We analysed 42 patients (32 males, 10 females). They recieved abdominal CT examination and died within a year. First, we got C.I. from their CT films. Then we got Surface Involved (S.I.) of atherosclerotic lesion from their autopsied abdominal aorta with pathological observation. The correlation coefficient between C.I. and S.I. was 0.83 (p<0.001). So we may use C.I. for the evaluation of abdominal aortic atherosclerosis. (author)

  9. Practical considerations for obtaining high quality quantitative computed tomography data of the skeletal system.

    Science.gov (United States)

    Troy, Karen L; Edwards, W Brent

    2018-05-01

    Quantitative CT (QCT) analysis involves the calculation of specific parameters such as bone volume and density from CT image data, and can be a powerful tool for understanding bone quality and quantity. However, without careful attention to detail during all steps of the acquisition and analysis process, data can be of poor- to unusable-quality. Good quality QCT for research requires meticulous attention to detail and standardization of all aspects of data collection and analysis to a degree that is uncommon in a clinical setting. Here, we review the literature to summarize practical and technical considerations for obtaining high quality QCT data, and provide examples of how each recommendation affects calculated variables. We also provide an overview of the QCT analysis technique to illustrate additional opportunities to improve data reproducibility and reliability. Key recommendations include: standardizing the scanner and data acquisition settings, minimizing image artifacts, selecting an appropriate reconstruction algorithm, and maximizing repeatability and objectivity during QCT analysis. The goal of the recommendations is to reduce potential sources of error throughout the analysis, from scan acquisition to the interpretation of results. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. Quantitative analysis of rectal cancer by spectral domain optical coherence tomography

    Science.gov (United States)

    Zhang, Q. Q.; Wu, X. J.; Tang, T.; Zhu, S. W.; Yao, Q.; Gao, Bruce Z.; Yuan, X. C.

    2012-08-01

    To quantify OCT images of rectal tissue for clinic diagnosis, the scattering coefficient of the tissue is extracted by curve fitting the OCT signals to a confocal single model. A total of 1000 measurements (half and half of normal and malignant tissues) were obtained from 16 recta. The normal rectal tissue has a larger scattering coefficient ranging from 1.09 to 5.41 mm-1 with a mean value of 2.29 mm-1 (std:±0.32), while the malignant group shows lower scattering property and the values ranging from 0.25 to 2.69 mm-1 with a mean value of 1.41 mm-1 (std:±0.18). The peri-cancer of recta has also been investigated to distinguish the difference between normal and malignant rectal tissue. The results demonstrate that the quantitative analysis of the rectal tissue can be used as a promising diagnostic criterion of early rectal cancer, which has great value for clinical medical applications.

  11. A noninvasive approach to quantitative functional brain mapping with H215O and positron emission tomography

    International Nuclear Information System (INIS)

    Fox, P.T.; Mintun, M.A.; Raichle, M.E.; Herscovitch, P.

    1984-01-01

    Positron emission tomographic (PET) measurements of regional cerebral blood flow (rCBF) with intravenously administered 15 O-labeled water and an adaptation of the Kety autoradiographic model are well suited to the study of functional-anatomical correlations within the human brain. This model requires arterial blood sampling to determine rCBF from the regional tissue radiotracer concentration (Cr) recorded by the tomograph. Based upon the well-defined, nearly linear relation between Cr and rCBF inherent in the model, we have developed a method for estimating changes in rCBF from changes in Cr without calculating true rCBF and thus without arterial sampling. This study demonstrates that quantitative functional brain mapping does not require the determination of rCBF from Cr when regional neuronal activation is expressed as the change in rCBF from an initial, resting-state measurement. Patterned-flash visual stimulation was used to produce a wide range of increases in rCBF within the striate cortex. Changes in occipital rCBF were found to be accurately estimated directly from Cr over a series of 56 measurements on eight subjects. This adaptation of the PET/autoradiographic method serves to simplify its application and to make it more acceptable to the subject

  12. Cone beam computed tomography for diagnosis of bisphosphonate-related osteonecrosis of the jaw: evaluation of quantitative and qualitative image parameters

    International Nuclear Information System (INIS)

    Guggenberger, Roman; Koral, Emrah; Andreisek, Gustav; Zemann, Wolfgang; Jacobsen, Christine; Metzler, Philipp

    2014-01-01

    To assess the diagnostic performance of quantitative and qualitative image parameters in cone-beam computed tomography (CBCT) for diagnosis of bisphosphonate-related osteonecrosis of the jaw (BRONJ). A BRONJ (22 patients, mean age 70.0 years) group was age and gender matched to a healthy control group (22 patients, mean age 68.0 years). On CBCT images two independent readers performed quantitative bone density value (BDV) measurements with region and volume-of-interest (ROI and VOI) based approaches and qualitative scoring of BRONJ-associated necrosis, sclerosis and periosteal thickening (1 = not present to 5 = definitely present). Intraoperative and clinical findings served as standard of reference. Interreader agreements and diagnostic performance were assessed by intraclass correlation coefficients (ICC), kappa-statistics and receiver-operating characteristic (ROC) analysis. Twenty-three regions in 22 patients were affected by BRONJ. ICC values for mean BDV VOI and mean BDV ROI were 0.864 and 0.968, respectively (p < 0.001). The area under the curve (AUC) for mean BDV VOI and mean BDV ROI was 0.58/0.83 with a sensitivity of 57/83 % and specificity of 61/77 % for diagnosis of BRONJ, respectively. Kappa values for presence of necrosis, sclerosis and periosteal thickening were 0.575, 0.617 and 0.885, respectively. AUC values for qualitative parameters ranged between 0.90-0.96 with sensitivity of 96 % and specificities between 79-96 % at respective cutoff scores. BRONJ can be effectively diagnosed with CBCT. Qualitative image parameters yield a higher diagnostic performance than quantitative parameters, and ROI-based attenuation measurements were more accurate than VOI-based measurements. (orig.)

  13. Quantitative computed tomography (QCT) as a radiology reporting tool by using optical character recognition (OCR) and macro program.

    Science.gov (United States)

    Lee, Young Han; Song, Ho-Taek; Suh, Jin-Suck

    2012-12-01

    The objectives are (1) to introduce a new concept of making a quantitative computed tomography (QCT) reporting system by using optical character recognition (OCR) and macro program and (2) to illustrate the practical usages of the QCT reporting system in radiology reading environment. This reporting system was created as a development tool by using an open-source OCR software and an open-source macro program. The main module was designed for OCR to report QCT images in radiology reading process. The principal processes are as follows: (1) to save a QCT report as a graphic file, (2) to recognize the characters from an image as a text, (3) to extract the T scores from the text, (4) to perform error correction, (5) to reformat the values into QCT radiology reporting template, and (6) to paste the reports into the electronic medical record (EMR) or picture archiving and communicating system (PACS). The accuracy test of OCR was performed on randomly selected QCTs. QCT as a radiology reporting tool successfully acted as OCR of QCT. The diagnosis of normal, osteopenia, or osteoporosis is also determined. Error correction of OCR is done with AutoHotkey-coded module. The results of T scores of femoral neck and lumbar vertebrae had an accuracy of 100 and 95.4 %, respectively. A convenient QCT reporting system could be established by utilizing open-source OCR software and open-source macro program. This method can be easily adapted for other QCT applications and PACS/EMR.

  14. Quantitative computed tomography for the prediction of pulmonary function after lung cancer surgery: a simple method using simulation software.

    Science.gov (United States)

    Ueda, Kazuhiro; Tanaka, Toshiki; Li, Tao-Sheng; Tanaka, Nobuyuki; Hamano, Kimikazu

    2009-03-01

    The prediction of pulmonary functional reserve is mandatory in therapeutic decision-making for patients with resectable lung cancer, especially those with underlying lung disease. Volumetric analysis in combination with densitometric analysis of the affected lung lobe or segment with quantitative computed tomography (CT) helps to identify residual pulmonary function, although the utility of this modality needs investigation. The subjects of this prospective study were 30 patients with resectable lung cancer. A three-dimensional CT lung model was created with voxels representing normal lung attenuation (-600 to -910 Hounsfield units). Residual pulmonary function was predicted by drawing a boundary line between the lung to be preserved and that to be resected, directly on the lung model. The predicted values were correlated with the postoperative measured values. The predicted and measured values corresponded well (r=0.89, plung cancer surgery and helped to identify patients whose functional reserves are likely to be underestimated. Hence, this modality should be utilized for patients with marginal pulmonary function.

  15. Quantitative myocardial thallium single-photon emission computed tomography in normal women: demonstration of age-related differences

    International Nuclear Information System (INIS)

    Cohen, M.; Touzery, C.; Cottin, Y.; Benoit, T.; Athis, P. d'; Roy, S.; Louis, P.; Wolf, J.E.; Rigo, P.; Brunotte, F.

    1996-01-01

    The aim of this study is the development of a database of normal women for quantitative analysis of exercise and reinjection myocardial single-photon emission computed tomography (SPET). We studied 101 subjects (40 males and 61 females) with less than 5% likelihood of coronary artery disease. All patients underwent stress and rest thallium-201 myocardial SPET. Myocardial stress was induced by bicycle exercise test (n=51), dipyridamole infusion (n=27) or a combined test (n=23). Multivariate ANOVA showed that the type of stress did not influence the percentage of thallium uptake for each region. Significant differences between men and women were found for the percentage of uptake in the inferior and the anterior wall. The most original finding of this study is the correlation between age and thallium uptake in the three regions of the anterior wall, showing an increase in measured thallium uptake with age for women. Consequently, two groups of women, those under and those over 55 years old, were separated, with a significantly lower tracer uptake in the anterior wall in the younger age group. (orig./MG)

  16. Quantitative imaging of cerebral blood flow velocity and intracellular motility using dynamic light scattering-optical coherence tomography.

    Science.gov (United States)

    Lee, Jonghwan; Radhakrishnan, Harsha; Wu, Weicheng; Daneshmand, Ali; Climov, Mihail; Ayata, Cenk; Boas, David A

    2013-06-01

    This paper describes a novel optical method for label-free quantitative imaging of cerebral blood flow (CBF) and intracellular motility (IM) in the rodent cerebral cortex. This method is based on a technique that integrates dynamic light scattering (DLS) and optical coherence tomography (OCT), named DLS-OCT. The technique measures both the axial and transverse velocities of CBF, whereas conventional Doppler OCT measures only the axial one. In addition, the technique produces a three-dimensional map of the diffusion coefficient quantifying nontranslational motions. In the DLS-OCT diffusion map, we observed high-diffusion spots, whose locations highly correspond to neuronal cell bodies and whose diffusion coefficient agreed with that of the motion of intracellular organelles reported in vitro in the literature. Therefore, the present method has enabled, for the first time to our knowledge, label-free imaging of the diffusion-like motion of intracellular organelles in vivo. As an example application, we used the method to monitor CBF and IM during a brief ischemic stroke, where we observed an induced persistent reduction in IM despite the recovery of CBF after stroke. This result supports that the IM measured in this study represent the cellular energy metabolism-related active motion of intracellular organelles rather than free diffusion of intracellular macromolecules.

  17. Quantitative computed tomography of lung parenchyma in patients with emphysema: analysis of higher-density lung regions

    Science.gov (United States)

    Lederman, Dror; Leader, Joseph K.; Zheng, Bin; Sciurba, Frank C.; Tan, Jun; Gur, David

    2011-03-01

    Quantitative computed tomography (CT) has been widely used to detect and evaluate the presence (or absence) of emphysema applying the density masks at specific thresholds, e.g., -910 or -950 Hounsfield Unit (HU). However, it has also been observed that subjects with similar density-mask based emphysema scores could have varying lung function, possibly indicating differences of disease severity. To assess this possible discrepancy, we investigated whether density distribution of "viable" lung parenchyma regions with pixel values > -910 HU correlates with lung function. A dataset of 38 subjects, who underwent both pulmonary function testing and CT examinations in a COPD SCCOR study, was assembled. After the lung regions depicted on CT images were automatically segmented by a computerized scheme, we systematically divided the lung parenchyma into different density groups (bins) and computed a number of statistical features (i.e., mean, standard deviation (STD), skewness of the pixel value distributions) in these density bins. We then analyzed the correlations between each feature and lung function. The correlation between diffusion lung capacity (DLCO) and STD of pixel values in the bin of -910HU lung parenchyma and lung function, which indicates that similar to the conventional density mask method, the pixel value distribution features in "viable" lung parenchyma areas may also provide clinically useful information to improve assessments of lung disease severity as measured by lung functional tests.

  18. The Quantitative Measurements of Vascular Density and Flow Area of Optic Nerve Head Using Optical Coherence Tomography Angiography.

    Science.gov (United States)

    Bazvand, Fatemeh; Mirshahi, Reza; Fadakar, Kaveh; Faghihi, Houshangh; Sabour, Siamak; Ghassemi, Fariba

    2017-08-01

    The purpose of this study was to evaluate the vascular density (VD) and the flow area on optic nerve head (ONH) and peripapillary area, and the impact of age and sex using optical coherence tomography angiography (OCTA) in healthy human subjects. Both eyes of each volunteer were scanned by an RTVue XR Avanti; Optovue with OCTA using the split-spectrum amplitude-decorrelation angiography algorithm technique. Masked graders evaluated enface angiodisc OCTA data. The flow area of ONH and the VD were automatically calculated. A total of 79 eyes of patients with a mean age of 37.03±11.27 were examined. The total ONH (papillary and peripapillary) area VD was 56.03%±4.55%. The flow area of the ONH was 1.74±0.10 mm/1.34 mm. The temporal and inferotemporal peripapillary VD was different between male and female patients. Increasing age causes some changes in the flow area of the ONH and the papillary VD from the third to the fourth decade (analysis of variance test; P<0.05). A normal quantitative database of the flow area and VD of the papillary and peripapillary area, obtained by RTVue XR with OCT angiography technique, is presented here.

  19. Quantitative exercise technetium-99m tetrofosmin myocardial tomography for the identification and localization of coronary artery disease

    International Nuclear Information System (INIS)

    Sullo, P.; Cuocolo, A.; Nicolai, E.; Cardei, S.; Nappi, A.; Squame, F.; Covelli, E.M.; Pace, L.; Salvatore, M.

    1996-01-01

    The aim of this study was to evaluate the accuracy of quantitative 1-day exercise-rest technetium-99m tetrofosmin tomography in the identification of patients with coronary artery disease (CAD) and in the detection of individual stenosed coronary vessels. Sixty-one patients with suspected CAD who underwent coronary angiography and 13 normal volunteers were studied. All patients were submitted to two i.v. injections of 99m Tc-tetrofosmin, one at peak exercise (370 MBq) and the other (1110 MBq) at rest 3 h after exercise (images 15-30 min after injection for both studies). All patients with CAD (≥50% luminal stenosis) (n=50) had an abnormal 99m Tc-tetrofosmin tomogram. Only one patient without significant coronary narrowing showed abnormal findings. Overall senstivity, specificity and diagnostic accuracy in the detection of individual stenosed vissels were 77%, 93% and 85%, respectively. Sensitivity and diagnostic accuracy in the identification of individuals stenosed coronary vessels were significantly higher (P 75%). (orig.)

  20. How do trees grow? Response from the graphical and quantitative analyses of computed tomography scanning data collected on stem sections.

    Science.gov (United States)

    Dutilleul, Pierre; Han, Li Wen; Beaulieu, Jean

    2014-06-01

    Tree growth, as measured via the width of annual rings, is used for environmental impact assessment and climate back-forecasting. This fascinating natural process has been studied at various scales in the stem (from cell and fiber within a growth ring, to ring and entire stem) in one, two, and three dimensions. A new approach is presented to study tree growth in 3D from stem sections, at a scale sufficiently small to allow the delineation of reliable limits for annual rings and large enough to capture directional variation in growth rates. The technology applied is computed tomography scanning, which provides - for one stem section - millions of data (indirect measures of wood density) that can be mapped, together with a companion measure of dispersion and growth ring limits in filigree. Graphical and quantitative analyses are reported for white spruce trees with circular vs non-circular growth. Implications for dendroclimatological research are discussed. Copyright © 2014 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  1. Tracheomalacia before and after aortosternopexy: dynamic and quantitative assessment by electron-beam computed tomography with clinical correlation

    International Nuclear Information System (INIS)

    Kao, S.C.S.; Kimura, K.; Smith, W.L.; Sato, Y.

    1995-01-01

    To correlate the dynamics of tracheal collapse with clinical upper airway obstruction before and after aortosternopexy, seven boys and three girls (mean age, 10 months) underwent dynamic evaluation of the trachea by electron-beam computed tomography (EBCT). The site, extent, and severity of collapse were correlated with symptomatology and details of operative procedure. When >50% area collapse was used as the criterion for tracheomalacia, segmental involvement occurred above the aortic arch in all patients, extending to the aortic arch level in only four. Tracheomalacia involved two or fewer 8-mm levels in seven patients and more than two levels in three. Eight patients underwent one aortosternopexy procedure, resulting in clinical improvement in six and correlating well with EBCT findings. Of the remaining two patients who had single aortosternopexy and did not show clinical and radiographic improvement, one required operative repair of a vascular ring and the other continued to have recurrent respiratory tract infections. On the basis of EBCT findings, two patients required additional innominate arteriopexies: One improved, and the other remained symptomatic, requiring tracheostomy. EBCT is a noninvasive modality that allows preoperative diagnosis of tracheomalacia. More importantly, the operative decision and technique are guided by an objective and quantitative assessment of tracheal collapse. (orig.)

  2. A quantitative exploration of the effects of workplace bullying on ...

    African Journals Online (AJOL)

    hefere

    types of hostile communication and behaviour are used (Tracy, .... Qualitative and quantitative studies explored the effects of WPB on educators. Whereas ... An array of research methods has thus been used to investigate the effects of WPB on.

  3. Micro-computed tomography characterization of tissue engineering scaffolds: effects of pixel size and rotation step.

    Science.gov (United States)

    Cengiz, Ibrahim Fatih; Oliveira, Joaquim Miguel; Reis, Rui L

    2017-08-01

    Quantitative assessment of micro-structure of materials is of key importance in many fields including tissue engineering, biology, and dentistry. Micro-computed tomography (µ-CT) is an intensively used non-destructive technique. However, the acquisition parameters such as pixel size and rotation step may have significant effects on the obtained results. In this study, a set of tissue engineering scaffolds including examples of natural and synthetic polymers, and ceramics were analyzed. We comprehensively compared the quantitative results of µ-CT characterization using 15 acquisition scenarios that differ in the combination of the pixel size and rotation step. The results showed that the acquisition parameters could statistically significantly affect the quantified mean porosity, mean pore size, and mean wall thickness of the scaffolds. The effects are also practically important since the differences can be as high as 24% regarding the mean porosity in average, and 19.5 h and 166 GB regarding the characterization time and data storage per sample with a relatively small volume. This study showed in a quantitative manner the effects of such a wide range of acquisition scenarios on the final data, as well as the characterization time and data storage per sample. Herein, a clear picture of the effects of the pixel size and rotation step on the results is provided which can notably be useful to refine the practice of µ-CT characterization of scaffolds and economize the related resources.

  4. Small animal positron emission tomography with gas detectors. Simulations, prototyping, and quantitative image reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Vernekohl, Don

    2014-04-15

    plain surfaces, predicted by simulations, was observed. Third, as the production of photon converters is time consuming and expensive, it was investigated whether or not thin gas detectors with single-lead-layer-converters would be an alternative to the HIDAC converter design. Following simulations, those concepts potentially offer impressive coincidence sensitivities up to 24% for plain lead foils and up to 40% for perforated lead foils. Fourth, compared to other PET scanner systems, the HIDAC concept suffers from missing energy information. Consequently, a substantial amount of scatter events can be found within the measured data. On the basis of image reconstruction and correction techniques the influence of random and scatter events and their characteristics on several simulated phantoms were presented. It was validated with the HIDAC simulator that the applied correction technique results in perfectly corrected images. Moreover, it was shown that the simulator is a credible tool to provide quantitatively improved images. Fifth, a new model for the non-collinearity of the positronium annihilation was developed, since it was observed that the model implemented in the GATE simulator does not correspond to the measured observation. The input parameter of the new model was trimmed to match to a point source measurement. The influence of both models on the spatial resolution was studied with three different reconstruction methods. Furthermore, it was demonstrated that the reduction of converter depth, proposed for increased sensitivity, also has an advantage on the spatial resolution and that a reduction of the FOV from 17 cm to 4 cm (with only 2 detector heads) results in a remarkable sensitivity increase of 150% and a substantial increase in spatial resolution. The presented simulations for the spatial resolution analysis used an intrinsic detector resolution of 0.125 x 0.125 x 3.2 mm{sup 3} and were able to reach fair resolutions down to 0.9-0.5 mm, which is an

  5. Early Assessment of Treatment Responses During Radiation Therapy for Lung Cancer Using Quantitative Analysis of Daily Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Jijo; Yang, Cungeng [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States); Wu, Hui [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States); The Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou (China); Tai, An [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States); Dalah, Entesar [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States); Department of Medical Diagnostic Imaging, College of Health Science, University of Sharjah (United Arab Emirates); Zheng, Cheng [Biostatistics, Joseph. J. Zilber School of Public Health, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin (United States); Johnstone, Candice [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States); Kong, Feng-Ming [Department of Radiation Oncology, Indiana University, Indianapolis, Indiana (United States); Gore, Elizabeth [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States); Li, X. Allen, E-mail: ali@mcw.edu [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin (United States)

    2017-06-01

    Purpose: To investigate early tumor and normal tissue responses during the course of radiation therapy (RT) for lung cancer using quantitative analysis of daily computed tomography (CT) scans. Methods and Materials: Daily diagnostic-quality CT scans acquired using CT-on-rails during CT-guided RT for 20 lung cancer patients were quantitatively analyzed. On each daily CT set, the contours of the gross tumor volume (GTV) and lungs were generated and the radiation dose delivered was reconstructed. The changes in CT image intensity (Hounsfield unit [HU]) features in the GTV and the multiple normal lung tissue shells around the GTV were extracted from the daily CT scans. The associations between the changes in the mean HUs, GTV, accumulated dose during RT delivery, and patient survival rate were analyzed. Results: During the RT course, radiation can induce substantial changes in the HU histogram features on the daily CT scans, with reductions in the GTV mean HUs (dH) observed in the range of 11 to 48 HU (median 30). The dH is statistically related to the accumulated GTV dose (R{sup 2} > 0.99) and correlates weakly with the change in GTV (R{sup 2} = 0.3481). Statistically significant increases in patient survival rates (P=.038) were observed for patients with a higher dH in the GTV. In the normal lung, the 4 regions proximal to the GTV showed statistically significant (P<.001) HU reductions from the first to last fraction. Conclusion: Quantitative analysis of the daily CT scans indicated that the mean HUs in lung tumor and surrounding normal tissue were reduced during RT delivery. This reduction was observed in the early phase of the treatment, is patient specific, and correlated with the delivered dose. A larger HU reduction in the GTV correlated significantly with greater patient survival. The changes in daily CT features, such as the mean HU, can be used for early assessment of the radiation response during RT delivery for lung cancer.

  6. Abdominal body composition measured by quantitative computed tomography and risk of non-spine fractures

    DEFF Research Database (Denmark)

    Sheu, Y; Marshall, L M; Holton, K F

    2013-01-01

    The effect of abdominal adiposity and muscle on fracture is unclear in older men; therefore, we examined the association among 749 men aged 65+. Among various adipose tissues and muscle groups, lower psoas muscle volume and higher fatty infiltration of abdominal muscle contribute to higher fractu...

  7. Impact of multi-detector row computed tomography on the tactics of cardiovascular surgery. From qualitative evaluation to quantitative assessment

    International Nuclear Information System (INIS)

    Imagawa, Hiroshi; Kawachi, Kanji; Takano, Shinji

    2005-01-01

    We assessed the role of multi-detector row computed tomography in cardiovascular surgery. The efficacy of multi-detector row computed tomography was assessed concerning the graft patency of coronary artery bypass, arterial atheromatous degeneration, small vessel imaging, and left ventricular volume measurement. Images were reconstructed using both the volume-rendering and the maximum-intensity-profile methods. Arterial atherosclerotic degeneration was assessed by aortic wall volume and aortic calcification volume. In the assessment of bypass graft patency, multidetector row computed tomography showed a 98% correct positive ratio with sensitivity and specificity of 98% and 100%, respectively. Atheromatous degeneration showed matching results in more than 70% of cases compared with intraoperative findings. More than 92% of arterial branches with diameters of 3 mm or greater were detected by preoperative multi-detector row computed tomography images, though only 6% of branches with diameters of 2 mm or less could be visualized. There was a positive linear correlation between left ventricular volumes determined by multi-detector row computed tomography and those calculated from cine angiography. Multi-detector row computed tomography clearly visualized coronary bypass grafts and aortic arterial branches, providing detailed vascular images. Atheromatous degeneration assessed by multi-detector row computed tomography was equivalent with intraoperative findings in more than 70% of cases. Left ventricular volumes measured by multi-detector row computed tomography correlated closely with those determined by cine-angiography. Multidetector row computed tomography is an efficient and promising modality in cardiovascular surgery. (author)

  8. Please Don't Move-Evaluating Motion Artifact From Peripheral Quantitative Computed Tomography Scans Using Textural Features.

    Science.gov (United States)

    Rantalainen, Timo; Chivers, Paola; Beck, Belinda R; Robertson, Sam; Hart, Nicolas H; Nimphius, Sophia; Weeks, Benjamin K; McIntyre, Fleur; Hands, Beth; Siafarikas, Aris

    Most imaging methods, including peripheral quantitative computed tomography (pQCT), are susceptible to motion artifacts particularly in fidgety pediatric populations. Methods currently used to address motion artifact include manual screening (visual inspection) and objective assessments of the scans. However, previously reported objective methods either cannot be applied on the reconstructed image or have not been tested for distal bone sites. Therefore, the purpose of the present study was to develop and validate motion artifact classifiers to quantify motion artifact in pQCT scans. Whether textural features could provide adequate motion artifact classification performance in 2 adolescent datasets with pQCT scans from tibial and radial diaphyses and epiphyses was tested. The first dataset was split into training (66% of sample) and validation (33% of sample) datasets. Visual classification was used as the ground truth. Moderate to substantial classification performance (J48 classifier, kappa coefficients from 0.57 to 0.80) was observed in the validation dataset with the novel texture-based classifier. In applying the same classifier to the second cross-sectional dataset, a slight-to-fair (κ = 0.01-0.39) classification performance was observed. Overall, this novel textural analysis-based classifier provided a moderate-to-substantial classification of motion artifact when the classifier was specifically trained for the measurement device and population. Classification based on textural features may be used to prescreen obviously acceptable and unacceptable scans, with a subsequent human-operated visual classification of any remaining scans. Copyright © 2017 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

  9. Population-Stratified Analysis of Bone Mineral Density Distribution in Cervical and Lumbar Vertebrae of Chinese from Quantitative Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yong [Department of Radiology, The Fourth Clinical Medical College of Peking University, Beijing Jishuitan Hospital, Beijing 100035 (China); Zhou, Zhuang [Department of Orthopedic Oncology, The Third Hospital of Hebei Medical University, Shijiazhuang 050051 (China); Wu, Cheng' ai; Zhao, Danhui; Wang, Chao [Beijing Institute of Traumatology and Orthopedics, Beijing 100035 (China); Cheng, Xiaoguang; Cai, Wei; Wang, Ling; Duanmu, Yangyang; Zhang, Chenxin [Department of Radiology, The Fourth Clinical Medical College of Peking University, Beijing Jishuitan Hospital, Beijing 100035 (China); Tian, Wei [Department of Spine Surgery, The Fourth Clinical Medical College of Peking University, Beijing Jishuitan Hospital, Beijing 100035 (China)

    2016-11-01

    To investigate the bone mineral density (BMD) of cervical vertebrae in a population-stratified manner and correlate with that of the lumbar vertebrae. Five hundred and ninety-eight healthy volunteers (254 males, 344 females), ranging from 20 to 64 years of age, were recruited for volumetric BMD (vBMD) measurements by quantitative computed tomography. Basic information (age, height, weight, waistline, and hipline), and vBMD of the cervical and lumbar vertebrae (C2–7 and L2–4) were recorded. Comparisons among sex, age groups and different levels of vertebrae were analyzed using analysis of variance. Linear regression was performed for relevance of different vertebral levels. The vBMD of cervical and lumbar vertebrae was higher in females than males in each age group. The vBMD of the cervical and lumbar vertebrae in males and the vBMD of lumbar vertebrae in females decreased with aging. In each age group, the vBMD of the cervical vertebrae was higher than that of the lumbar vertebrae with gradual decreases from C2 to C7 except for C3; moreover, the vBMD of C6 and C7 was significantly different from that of C2–5. Correlations of vBMD among different cervical vertebrae (females: r = 0.62–0.94; males: r = 0.63–0.94) and lumbar vertebrae (males: r = 0.93–0.98; females: r = 0.82–0.97) were statistically significant at each age group. The present study provided normative data of cervical vertebrae in an age- and sex-stratified manner. Sex differences in vBMD prominently vary with age, which can be helpful to design a more comprehensive pre-operative surgical plan.

  10. Population=stratified analysis of bone mineral density distribution in cervical and lumbar vertebrae of chinese from quantitative computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yong; Cheng, Xiaoguang; Cai, Wei; Wang, Ling; Duanmu, Yangyang; Zhang, Chen Xin [Dept. of Radiology, The Fourth Clinical Medical College of Peking University, Beijing Jishuitan Hospital, Beijing (China); Zhou, Zhuang [Dept. of Orthopedic Oncology, The Third Hospital of Hebei Medical University, Shijiazhuang (China); Wu, Cheng' ai; Zhao, Danhui; Wang, Chao [Beijing Institute of Traumatology and Orthopedics, Beijing (China); Tian, Wei [Dept. of Spine Surgery, The Fourth Clinical Medical College of Peking University, Beijing Jishuitan Hospital, Beijing (China)

    2016-09-15

    To investigate the bone mineral density (BMD) of cervical vertebrae in a population-stratified manner and correlate with that of the lumbar vertebrae. Five hundred and ninety-eight healthy volunteers (254 males, 344 females), ranging from 20 to 64 years of age, were recruited for volumetric BMD (vBMD) measurements by quantitative computed tomography. Basic information (age, height, weight, waistline, and hipline), and vBMD of the cervical and lumbar vertebrae (C2–7 and L2–4) were recorded. Comparisons among sex, age groups and different levels of vertebrae were analyzed using analysis of variance. Linear regression was performed for relevance of different vertebral levels. The vBMD of cervical and lumbar vertebrae was higher in females than males in each age group. The vBMD of the cervical and lumbar vertebrae in males and the vBMD of lumbar vertebrae in females decreased with aging. In each age group, the vBMD of the cervical vertebrae was higher than that of the lumbar vertebrae with gradual decreases from C2 to C7 except for C3; moreover, the vBMD of C6 and C7 was significantly different from that of C2–5. Correlations of vBMD among different cervical vertebrae (females: r = 0.62–0.94; males: r = 0.63–0.94) and lumbar vertebrae (males: r = 0.93–0.98; females: r = 0.82–0.97) were statistically significant at each age group. The present study provided normative data of cervical vertebrae in an age- and sex-stratified manner. Sex differences in vBMD prominently vary with age, which can be helpful to design a more comprehensive pre-operative surgical plan.

  11. Bone-marrow densitometry: Assessment of marrow space of human vertebrae by single energy high resolution-quantitative computed tomography

    International Nuclear Information System (INIS)

    Peña, Jaime A.; Damm, Timo; Bastgen, Jan; Barkmann, Reinhard; Glüer, Claus C.; Thomsen, Felix; Campbell, Graeme M.

    2016-01-01

    Purpose: Accurate noninvasive assessment of vertebral bone marrow fat fraction is important for diagnostic assessment of a variety of disorders and therapies known to affect marrow composition. Moreover, it provides a means to correct fat-induced bias of single energy quantitative computed tomography (QCT) based bone mineral density (BMD) measurements. The authors developed new segmentation and calibration methods to obtain quantitative surrogate measures of marrow-fat density in the axial skeleton. Methods: The authors developed and tested two high resolution-QCT (HR-QCT) based methods which permit segmentation of bone voids in between trabeculae hypothesizing that they are representative of bone marrow space. The methods permit calculation of marrow content in units of mineral equivalent marrow density (MeMD). The first method is based on global thresholding and peeling (GTP) to define a volume of interest away from the transition between trabecular bone and marrow. The second method, morphological filtering (MF), uses spherical elements of different radii (0.1–1.2 mm) and automatically places them in between trabeculae to identify regions with large trabecular interspace, the bone-void space. To determine their performance, data were compared ex vivo to high-resolution peripheral CT (HR-pQCT) images as the gold-standard. The performance of the methods was tested on a set of excised human vertebrae with intact bone marrow tissue representative of an elderly population with low BMD. Results: 86% (GTP) and 87% (MF) of the voxels identified as true marrow space on HR-pQCT images were correctly identified on HR-QCT images and thus these volumes of interest can be considered to be representative of true marrow space. Within this volume, MeMD was estimated with residual errors of 4.8 mg/cm 3 corresponding to accuracy errors in fat fraction on the order of 5% both for GTP and MF methods. Conclusions: The GTP and MF methods on HR-QCT images permit noninvasive

  12. Bone-marrow densitometry: Assessment of marrow space of human vertebrae by single energy high resolution-quantitative computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Peña, Jaime A.; Damm, Timo; Bastgen, Jan; Barkmann, Reinhard; Glüer, Claus C., E-mail: glueer@rad.uni-kiel.de [Sektion Biomedizinische Bildgebung, Klinik für Radiologie und Neuroradiologie, Christian-Albrechts-Universität zu Kiel, Campus Kiel, Kiel 24118 (Germany); Thomsen, Felix [Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional del Sur, Bahía Blanca 8000 (Argentina); Campbell, Graeme M. [Sektion Biomedizinische Bildgebung, Klinik für Radiologie und Neuroradiologie, Christian-Albrechts-Universität zu Kiel, Campus Kiel, Kiel 24118, Germany and Institut für Biomechanik, Technische Universität Hamburg-Harburg (TUHH), Hamburg 21073 (Germany)

    2016-07-15

    Purpose: Accurate noninvasive assessment of vertebral bone marrow fat fraction is important for diagnostic assessment of a variety of disorders and therapies known to affect marrow composition. Moreover, it provides a means to correct fat-induced bias of single energy quantitative computed tomography (QCT) based bone mineral density (BMD) measurements. The authors developed new segmentation and calibration methods to obtain quantitative surrogate measures of marrow-fat density in the axial skeleton. Methods: The authors developed and tested two high resolution-QCT (HR-QCT) based methods which permit segmentation of bone voids in between trabeculae hypothesizing that they are representative of bone marrow space. The methods permit calculation of marrow content in units of mineral equivalent marrow density (MeMD). The first method is based on global thresholding and peeling (GTP) to define a volume of interest away from the transition between trabecular bone and marrow. The second method, morphological filtering (MF), uses spherical elements of different radii (0.1–1.2 mm) and automatically places them in between trabeculae to identify regions with large trabecular interspace, the bone-void space. To determine their performance, data were compared ex vivo to high-resolution peripheral CT (HR-pQCT) images as the gold-standard. The performance of the methods was tested on a set of excised human vertebrae with intact bone marrow tissue representative of an elderly population with low BMD. Results: 86% (GTP) and 87% (MF) of the voxels identified as true marrow space on HR-pQCT images were correctly identified on HR-QCT images and thus these volumes of interest can be considered to be representative of true marrow space. Within this volume, MeMD was estimated with residual errors of 4.8 mg/cm{sup 3} corresponding to accuracy errors in fat fraction on the order of 5% both for GTP and MF methods. Conclusions: The GTP and MF methods on HR-QCT images permit noninvasive

  13. Quantitation of the reconstruction quality of a four-dimensional computed tomography process for lung cancer patients

    International Nuclear Information System (INIS)

    Lu Wei; Parikh, Parag J.; El Naqa, Issam M.; Nystrom, Michelle M.; Hubenschmidt, James P.; Wahab, Sasha H.; Mutic, Sasa; Singh, Anurag K.; Christensen, Gary E.; Bradley, Jeffrey D.; Low, Daniel A.

    2005-01-01

    We have developed a four-dimensional computed tomography (4D CT) technique for mapping breathing motion in radiotherapy treatment planning. A multislice CT scanner (1.5 mm slices) operated in cine mode was used to acquire 12 contiguous slices in each couch position for 15 consecutive scans (0.5 s rotation, 0.25 s between scans) while the patient underwent simultaneous quantitative spirometry measurements to provide a sorting metric. The spirometry-sorted scans were used to reconstruct a 4D data set. A critical factor for 4D CT is quantifying the reconstructed data set quality which we measure by correlating the metric used relative to internal-object motion. For this study, the internal air content within the lung was used as a surrogate for internal motion measurements. Thresholding and image morphological operations were applied to delineate the air-containing tissues (lungs, trachea) from each CT slice. The Hounsfield values were converted to the internal air content (V). The relationship between the air content and spirometer-measured tidal volume (ν) was found to be quite linear throughout the lungs and was used to estimate the overall accuracy and precision of tidal volume-sorted 4D CT. Inspection of the CT-scan air content as a function of tidal volume showed excellent correlations (typically r>0.99) throughout the lung volume. Because of the discovered linear relationship, the ratio of internal air content to tidal volume was indicative of the fraction of air change in each couch position. Theoretically, due to air density differences within the lung and in room, the sum of these ratios would equal 1.11. For 12 patients, the mean value was 1.08±0.06, indicating the high quality of spirometry-based image sorting. The residual of a first-order fit between ν and V was used to estimate the process precision. For all patients, the precision was better than 8%, with a mean value of 5.1%±1.9%. This quantitative analysis highlights the value of using spirometry

  14. Risk Factors for Chronic Subdural Hematoma Recurrence Identified Using Quantitative Computed Tomography Analysis of Hematoma Volume and Density.

    Science.gov (United States)

    Stavrinou, Pantelis; Katsigiannis, Sotirios; Lee, Jong Hun; Hamisch, Christina; Krischek, Boris; Mpotsaris, Anastasios; Timmer, Marco; Goldbrunner, Roland

    2017-03-01

    Chronic subdural hematoma (CSDH), a common condition in elderly patients, presents a therapeutic challenge with recurrence rates of 33%. We aimed to identify specific prognostic factors for recurrence using quantitative analysis of hematoma volume and density. We retrospectively reviewed radiographic and clinical data of 227 CSDHs in 195 consecutive patients who underwent evacuation of the hematoma through a single burr hole, 2 burr holes, or a mini-craniotomy. To examine the relationship between hematoma recurrence and various clinical, radiologic, and surgical factors, we used quantitative image-based analysis to measure the hematoma and trapped air volumes and the hematoma densities. Recurrence of CSDH occurred in 35 patients (17.9%). Multivariate logistic regression analysis revealed that the percentage of hematoma drained and postoperative CSDH density were independent risk factors for recurrence. All 3 evacuation methods were equally effective in draining the hematoma (71.7% vs. 73.7% vs. 71.9%) without observable differences in postoperative air volume captured in the subdural space. Quantitative image analysis provided evidence that percentage of hematoma drained and postoperative CSDH density are independent prognostic factors for subdural hematoma recurrence. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. [Erroneous vision determination and quantitative effects].

    Science.gov (United States)

    Petersen, J

    1993-10-01

    The experimentally determined psychometric function for Landolt rings (8 orientations, 183 eyes) is used to calculate the statistics of visual acuity results according to DIN 58,220 and their bias due to deviations from DIN 58,220. Test procedure fulfilling DIN 58,220, criterion 3/5: With a second test the first result is reproduced in 33.7%. In 47% the difference is 1 step, in 16.2% 2 steps, and in 2.8% 3 steps. Selecting the highest acuity value out of several tests yields a bias of +0.44 steps (2 tests), +0.66 steps (3), +0.81 steps (4 tests). Deviations from DIN 58,220, criterion 3/5: Linearly instead of log-scaled optotypes: above acuity 0.2 the effect is minimal (test despite fulfilled break condition: bias +0.3 steps; Weakened criterion of 2/5: bias +0.89 steps. Visual acuity values can contain considerable errors. There is a need for more effective algorithms and an unbiased investigator. The solution is programmed automatic testing on a computer screen.

  16. Absorbed and effective dose from spiral and computed tomography for the dental implant planning

    International Nuclear Information System (INIS)

    Hong, Beong Hee; Han, Won Jeong; Kim, Eun Kyung

    2001-01-01

    To evaluate the absorbed and effective doses of spiral and computed tomography for the dental implant planning. For radiographic projection. TLD chips were placed in 22 sites of humanoid phantom to record the exposure to skin and the mean absorbed dose to bone marrow, thyroid, pituitary, parotid and submandibular glands and nesophages. Effective dose was calculated, using the method suggested by Frederiksen at al.. Patient situations of a single tooth gap in upper and lower midline region, edentulous maxilla and mandible were simulated for spiral tomography. 35 axial slices (maxilla) and 40 axial slices (mandible) with low and standard dose setting were used for computed tomography. All the radiographic procedures were repeated three times. The mean effective dose in case of maxilla was 0.865 mSv, 0.452 mSv, 0.136 mSv and 0.025 mSv, in spiral tomography of complete edentulous maxilla, computed tomography with standard mAs, computed tomography with low mAs and spiral tomography of a single tooth gap (p<0.05). That in case of mandible was 0.614 mSv, 0.448 mSv, 0.137 mSv and 0.036 mSv, in spiral tomography of complete edentulous mandible, computed tomography with standard mAs, computed tomography with low mAs and spiral tomography of a single tooth gap (p<0.05). Based on these results, it can be concluded that low mAs computed tomography is recommended instead of spiral tomography for the complete edentulous maxilla and mandible dental implant treatment planning

  17. Bone mineral density measurements using peripheral quantitative computed tomography (pQCT). An evaluation of its clinical utility

    International Nuclear Information System (INIS)

    Imai, Yoshiyuki

    1999-01-01

    Bone densitometry has become a major tool for the risk assessment of osteoporosis. Peripheral quantitative computed tomography (pQCT) has the potential to measure true volumetric bone mineral density (BMD, g/cm 3 ) separating cortical and trabecular BMD. The most widely used dual-energy X-ray absorptiometry (DXA) provides areal BMD (mg/cm 2 ). The purpose of this study was to clarify the clinical usefulness of pQCT as a method for bone mineral measurement. The pQCT measurements were carried out at the ultradistal- and mid-radius and the tibia using a Densiscan-1000 (Scanco Medical AG). In both sexes, radial and tibial BMDs in the elderly group (aged more than 60 y.o., 17 men, and 26 women) were significantly lower than those in the young group (aged 20-44 y.o., 107 men and 78 women). The percent difference between the two groups was the greatest in trabecular BMD (D50). As to the sex-related difference, the mean values of radial and tibial BMD in men were significantly higher than in women in elderly groups. The radial BMDs measured by pQCT correlated significantly with BMDs in the lumbar spine, radius and femoral neck measured by DXA (p<0.001). Lumbar BMD measured by DXA showed the highest correlation to rD50 measured by pQCT. Diagnostic ability of pQCT and DXA to detect osteoporosis was determined by comparing BMD measurements. Kappa statistics showed that in general the diagnostic agreement between these measurements was fair or moderate. The discriminative ability of these methods for vertebral fracture was assessed by receiver operating characteristic (ROC) analysis. The areas under the ROC curves were 0.68, 0.71, 0.69 and 0.78 for D50, D100, P100 and L-BMD, respectively. These results indicate that BMD measurements made by pQCT can provide information regarding both trabecular and cortical BMD, and that this method has potential for the diagnosis and management of osteoporosis. (author)

  18. Repeatability, interocular correlation and agreement of quantitative swept-source optical coherence tomography angiography macular metrics in healthy subjects.

    Science.gov (United States)

    Fang, Danqi; Tang, Fang Yao; Huang, Haifan; Cheung, Carol Y; Chen, Haoyu

    2018-05-29

    To investigate the repeatability, interocular correlation and agreement of quantitative swept-source optical coherence tomography angiography (SS-OCTA) metrics in healthy subjects. Thirty-three healthy normal subjects were enrolled. The macula was scanned four times by an SS-OCTA system using the 3 mm×3 mm mode. The superficial capillary map images were analysed using a MATLAB program. A series of parameters were measured: foveal avascular zone (FAZ) area, FAZ perimeter, FAZ circularity, parafoveal vessel density, fractal dimension and vessel diameter index (VDI). The repeatability of four scans was determined by intraclass correlation coefficient (ICC). Then the averaged results were analysed for intereye difference, correlation and agreement using paired t-test, Pearson's correlation coefficient (r), ICC and Bland-Altman plot. The repeatability assessment of the macular metrics exported high ICC values (ranged from 0.853 to 0.996). There is no statistically significant difference in the OCTA metrics between the two eyes. FAZ area (ICC=0.961, r=0.929) and FAZ perimeter (ICC=0.884, r=0.802) showed excellent binocular correlation. Fractal dimension (ICC=0.732, r=0.578) and VDI (ICC=0.707, r=0.547) showed moderate binocular correlation, while parafoveal vessel density had poor binocular correlation. Bland-Altman plots showed the range of agreement was from -0.0763 to 0.0954 mm 2 for FAZ area and from -0.0491 to 0.1136 for parafoveal vessel density. The macular metrics obtained using SS-OCTA showed excellent repeatability in healthy subjects. We showed high intereye correlation in FAZ area and perimeter, moderate correlation in fractal dimension and VDI, while vessel density had poor correlation in normal healthy subjects. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  19. The Quantitative Measurements of Vascular Density and Flow Areas of Macula Using Optical Coherence Tomography Angiography in Normal Volunteers.

    Science.gov (United States)

    Ghassemi, Fariba; Fadakar, Kaveh; Bazvand, Fatemeh; Mirshahi, Reza; Mohebbi, Masoumeh; Sabour, Siamak

    2017-06-01

    The quantification of the density of macular vascular networks and blood flow areas in the foveal and parafoveal area in healthy subjects using optical coherence tomography angiography (OCTA). Cross-sectional, prospective study in an institutional setting at the Retina Services of Farabi Eye Hospital. One hundred twelve normal volunteers with no known ocular or systemic disease were included, including patient numbers (one or both eyes), selection procedures, inclusion/exclusion criteria, randomization procedure, and masking. En face angiogram OCTA was performed on a 3 mm × 3 mm region centered on the macula. Automated thresholding and measuring algorithm method for foveal and parafoveal blood flow and vascular density (VD) were used. The density of macular vascular networks and blood flow area in the foveal and parafoveal area were measured. A total of 224 healthy eyes from 112 subjects with a mean age of 36.4 years ± 11.3 years were included. In the foveal region, the VD of the superficial capillary network (sCN) was significantly higher than that of the deep capillary network (dCN) (31.1% ± 5.5% vs. 28.3% ± 7.2%; P < .001), whereas in the parafoveal area, VD was higher in the dCN (62.24% ± 2.8% vs. 56.5% ± 2.5%; P < .001). Flow area in the 1-mm radius circle in the sCN was less than in the dCN. Superficial foveal avascular zone (sFAZ) size was negatively correlated with the VD of the foveal sCN, but in the deep FAZ (dFAZ) was not correlated with VD or blood flow area of the fovea. There was no difference between measured VD and blood flow surface area in both eyes of the subjects. OCTA could be used as a noninvasive, repeatable, layer-free method in quantitative evaluation of VD and blood flow of macular area. The normal quantities of the vascular plexus density and flow will help in better understanding the pathophysiological basis of the vascular disease of retina. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:478-486.]. Copyright 2017, SLACK

  20. Can high-resolution peripheral quantitative computed tomography imaging of subchondral and cortical bone predict condylar fracture in Thoroughbred racehorses?

    Science.gov (United States)

    Trope, G D; Ghasem-Zadeh, A; Anderson, G A; Mackie, E J; Whitton, R C

    2015-07-01

    High-resolution 3D imaging may improve the prediction and/or early identification of condylar fractures of the distal metacarpus/tarsus and reduce the frequency of breakdown injury in racehorses. To test the hypotheses that horses suffering condylar fractures have higher bone volume fraction (BV/TV) of the distal metacarpal epiphysis, greater subchondral bone thickness at the fracture site and higher second moment of inertia in the metacarpal midshaft as identified with high-resolution 3D imaging. Cross-sectional study using cadaver material. Thoroughbreds that died on racetracks were grouped as: 1) horses with third metacarpal (McIII) fractures with a condylar component (cases, n = 13); 2) horses with no limb fracture (controls, n = 8); 3) horses with fractures in other bones or suspensory apparatus disruption (other fatal injuries, n = 16). The palmar condyles of McIII and the midshaft were examined with high resolution peripheral quantitative computed tomography (HR-pQCT). Statistical analysis included logistic regression and Spearman's correlation. There were no significant differences in BV/TV of distal McIII and second moment of inertia of the midshaft between cases and controls. Epiphyseal bone BV/TV was greater in injured limbs of horses with any fatal limb injury (Groups 1 and 3 combined) compared with controls (odds ratio = 1.20, 95% confidence interval 1.01-1.42, P = 0.034). An epiphyseal BV/TV>0.742 resulted in a sensitivity of 82.8% and specificity of 62.5% in identifying horses with fatal limb injury. In horses without condylar fracture, increased subchondral bone thickness was associated with palmar osteochondral disease lesions in the adjacent condyle (rs = 0.65, Phorses at risk of any fatal breakdown injury but not metacarpal condylar fractures. Measurement of parasagittal groove subchondral bone thickness is complicated by adjacent palmar osteochondral disease lesions. Thus, high-resolution imaging of the distal metacarpus appears to have limited

  1. Bone geometry in young male and female football players: a peripheral quantitative computed tomography (pQCT) study.

    Science.gov (United States)

    Lozano-Berges, Gabriel; Matute-Llorente, Ángel; Gómez-Bruton, Alejandro; González-Agüero, Alex; Vicente-Rodríguez, Germán; Casajús, José A

    2018-05-08

    The present study shows that football practice during growth may improve bone geometry in male and female football players. However, only females had better bone strength in comparison with controls. The aim of this study was to compare bone geometry in adolescent football players and controls. A total of 107 football players (71 males/36 females; mean age 12.7 ± 0.6/12.7 ± 0.6 years) and 42 controls (20 males/22 females; mean age 13.1 ± 1.4/12.7 ± 1.3 years) participated in this study. Total and trabecular volumetric bone mineral content (Tt.BMC/Tb.BMC), cross-sectional area (Tt.Ar/Tb.Ar), and bone strength index (BSI) were measured at 4% site of the non-dominant tibia by peripheral quantitative computed tomography (pQCT). Moreover, Tt.BMC, cortical BMC (Ct.BMC), Tt.Ar, cortical Ar (Ct.Ar), cortical thickness (Ct.Th), periosteal circumference (PC), endosteal circumference (EC), fracture load in X-axis, and polar strength strain index (SSIp) were measured at 38% site of the tibia. Multivariate analyses of covariance were used to compare bone pQCT variables between football players and controls using the tibia length and maturity offset as covariates. Female football players demonstrated 13.8-16.4% higher BSI, Ct.Th, fracture load in X-axis, and SSIp than controls (p  .0036). In relation to bone mineral content and area, male football players showed 8.8% higher Tt.Ar and Tb.Ar at the 4% site of the tibia when compared to controls; whereas 13.8-15.8% higher Tt.BMC, Ct.BMC, and Ct.Ar at the 38% site of the tibia were found in female football players than controls (p female adolescent football players presented better bone geometry and strength values than controls. In contrast, only bone geometry was higher in male football players than controls.

  2. Quantitative coronary plaque analysis predicts high-risk plaque morphology on coronary computed tomography angiography: results from the ROMICAT II trial.

    Science.gov (United States)

    Liu, Ting; Maurovich-Horvat, Pál; Mayrhofer, Thomas; Puchner, Stefan B; Lu, Michael T; Ghemigian, Khristine; Kitslaar, Pieter H; Broersen, Alexander; Pursnani, Amit; Hoffmann, Udo; Ferencik, Maros

    2018-02-01

    Semi-automated software can provide quantitative assessment of atherosclerotic plaques on coronary CT angiography (CTA). The relationship between established qualitative high-risk plaque features and quantitative plaque measurements has not been studied. We analyzed the association between quantitative plaque measurements and qualitative high-risk plaque features on coronary CTA. We included 260 patients with plaque who underwent coronary CTA in the Rule Out Myocardial Infarction/Ischemia Using Computer Assisted Tomography (ROMICAT) II trial. Quantitative plaque assessment and qualitative plaque characterization were performed on a per coronary segment basis. Quantitative coronary plaque measurements included plaque volume, plaque burden, remodeling index, and diameter stenosis. In qualitative analysis, high-risk plaque was present if positive remodeling, low CT attenuation plaque, napkin-ring sign or spotty calcium were detected. Univariable and multivariable logistic regression analyses were performed to assess the association between quantitative and qualitative high-risk plaque assessment. Among 888 segments with coronary plaque, high-risk plaque was present in 391 (44.0%) segments by qualitative analysis. In quantitative analysis, segments with high-risk plaque had higher total plaque volume, low CT attenuation plaque volume, plaque burden and remodeling index. Quantitatively assessed low CT attenuation plaque volume (odds ratio 1.12 per 1 mm 3 , 95% CI 1.04-1.21), positive remodeling (odds ratio 1.25 per 0.1, 95% CI 1.10-1.41) and plaque burden (odds ratio 1.53 per 0.1, 95% CI 1.08-2.16) were associated with high-risk plaque. Quantitative coronary plaque characteristics (low CT attenuation plaque volume, positive remodeling and plaque burden) measured by semi-automated software correlated with qualitative assessment of high-risk plaque features.

  3. Effectiveness of lead aprons in positron emission tomography

    International Nuclear Information System (INIS)

    Bezerra Fonseca, R.; Amaral, A.

    2008-01-01

    Full text: In the last two decades, Positron Emission Tomography (PET) has emerged as clinical diagnostic technique, becoming one of the fastest growing imaging tools in modern nuclear medicine. Because 511 keV annihilation photon energy is much higher than the photon with mean energy of 140 keV emitted in Single Photon Computed Tomography (SPECT), medical staff working in PET studies receive a higher dose than those working only with SPECT tracers do. As a result, special attention must be paid to keep radiation exposure as low as reasonably achievable (ALARA principle). Lead equivalent apron is the principal personal protective equipment for technologists occupationally exposed to ionizing radiation in medical procedures and may be an important component in the ALARA program. However, in practices involving PET, 0.5 mm lead equivalent aprons have been used regardless of photon's energy. In this context, this work was designed for evaluating radioprotective effectiveness of such aprons in PET procedures. For this, the operational quantities personal dose equivalent H p (0.07) and H p (10) have been assessed by using MCNP4C code in a model of individual exposure to small source of 511 keV photons, representing the situation of injection of the radiopharmaceutical, in two situations: technologists wearing and not wearing 0.5 mm lead aprons. To represent the technologist a mathematical anthropomorphic phantom was employed, and the simulated source to subject distances varied between 40 to 100 cm, in steps of 10 cm. The results showed no significant differences between the values obtained for H p (10) in the two situations, pointing out that that there is no radioprotective influence of wearing such aprons on PET practices. Compared to simulations without such device, H p (0.07) increased up about 26% when technologist is wearing radioprotective aprons, depending on the source to subject distance. On the basis of this work, 0.5 mm lead equivalent aprons should not be

  4. Quantitative assessment of diffuse optical tomography sensitivity to the cerebral cortex using a whole-head probe

    International Nuclear Information System (INIS)

    Perdue, Katherine L; Diamond, Solomon G; Fang Qianqian

    2012-01-01

    We quantify the variability in diffuse optical tomography (DOT) sensitivity over the cortical surface in eight young adult subjects. We use the 10/5 electroencephalography system as a basis for our whole-head optical high-density probe design. The contrast-to-noise ratio (CNR) is calculated along with the percentage of the cortex that is above a CNR = 0 dB threshold. We also quantify the effect of including vasculature on the forward model and list our assumptions that allow us to estimate light penetration depth in the head. We show that using the 10/5 system for the optical probe design allows for the measurement of 37% of the cortical surface on average, with a mean CNR in the visible region of 5.5 dB. Certain anatomical regions, such as the lateral occipital cortex, had a very high percentage above the CNR threshold, while other regions such as the cingulate cortex were not measurable. Vasculature blocked optical sensitivity over 1% of the cortex. Cortical coverage was positively correlated with intracranial volume and relative cerebrospinal fluid volume, and negatively correlated with relative scalp volume and skull volume. These contributions allow experimenters to understand how anatomical variation in a subject population may impact DOT or functional near-infrared spectroscopy measurements. (paper)

  5. Exercise-induced stunning continues for at least one hour: evaluation with quantitative gated single-photon emission tomography

    International Nuclear Information System (INIS)

    Paul, A.K.; Hasegawa, Shinji; Yoshioka, Jun; Tsujimura, Eiichiro; Yamaguchi, Hitoshi; Tokita, Naoki; Maruyama, Atsushi; Xiuli, Mu; Nishimura, Tsunehiko

    1999-01-01

    To elucidate the after-effect of exercise on left ventricular (LV) function, end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (LVEF) were evaluated at 1 h after exercise and at rest by technetium-99m tetrofosmin gated myocardial single-photon emission tomography (SPET) using an automated program in 53 subjects. The subjects were grouped as follows: normal scan (n = 16), ischaemia (n = 19) and infarction (n = 18), based on the interpretation of perfusion images. Postexercise LVEF did not differ from resting LVEF in the groups with normal scan and infarction. In patients with ischaemia, postexercise EDV (90±17 ml, mean ±SD) and ESV (44±15 ml) were significantly higher than EDV (84±15 ml, P = 0.001) and ESV (36±14 ml, P<0.0005) at rest. LVEF was significantly depressed 1 h after exercise (53%±9% vs 58%±9%, P<0.0001). In ischaemic patients with depressed postexercise LVEF, LVEF difference between rest and postexercise showed a significant correlation with the sum of defect scores, which were reversible from exercise to rest perfusion images (r = 0.92, P<0.0001). These results indicate that exercise-induced LV dysfunction (myocardial stunning) continues for at least 1 h in ischaemic patients and that the extent of LVEF depression is determined by the severity of ischaemia. (orig.)

  6. Exercise-induced stunning continues for at least one hour: evaluation with quantitative gated single-photon emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Paul, A.K.; Hasegawa, Shinji; Yoshioka, Jun; Tsujimura, Eiichiro; Yamaguchi, Hitoshi; Tokita, Naoki; Maruyama, Atsushi; Xiuli, Mu; Nishimura, Tsunehiko [Division of Tracer Kinetics, Biomedical Research Center, Osaka University Medical School, Suita, Osaka (Japan)

    1999-04-29

    To elucidate the after-effect of exercise on left ventricular (LV) function, end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (LVEF) were evaluated at 1 h after exercise and at rest by technetium-99m tetrofosmin gated myocardial single-photon emission tomography (SPET) using an automated program in 53 subjects. The subjects were grouped as follows: normal scan (n = 16), ischaemia (n = 19) and infarction (n = 18), based on the interpretation of perfusion images. Postexercise LVEF did not differ from resting LVEF in the groups with normal scan and infarction. In patients with ischaemia, postexercise EDV (90{+-}17 ml, mean {+-}SD) and ESV (44{+-}15 ml) were significantly higher than EDV (84{+-}15 ml, P = 0.001) and ESV (36{+-}14 ml, P<0.0005) at rest. LVEF was significantly depressed 1 h after exercise (53%{+-}9% vs 58%{+-}9%, P<0.0001). In ischaemic patients with depressed postexercise LVEF, LVEF difference between rest and postexercise showed a significant correlation with the sum of defect scores, which were reversible from exercise to rest perfusion images (r = 0.92, P<0.0001). These results indicate that exercise-induced LV dysfunction (myocardial stunning) continues for at least 1 h in ischaemic patients and that the extent of LVEF depression is determined by the severity of ischaemia. (orig.) With 7 figs., 19 refs.

  7. A method for volume determination of the orbit and its contents by high resolution axial tomography and quantitative digital image analysis.

    Science.gov (United States)

    Cooper, W C

    1985-01-01

    The various congenital and acquired conditions which alter orbital volume are reviewed. Previous investigative work to determine orbital capacity is summarized. Since these studies were confined to postmortem evaluations, the need for a technique to measure orbital volume in the living state is presented. A method for volume determination of the orbit and its contents by high-resolution axial tomography and quantitative digital image analysis is reported. This procedure has proven to be accurate (the discrepancy between direct and computed measurements ranged from 0.2% to 4%) and reproducible (greater than 98%). The application of this method to representative clinical problems is presented and discussed. The establishment of a diagnostic system versatile enough to expand the usefulness of computerized axial tomography and polytomography should add a new dimension to ophthalmic investigation and treatment.

  8. Effect of small mapping population sizes on reliability of quantitative ...

    African Journals Online (AJOL)

    A limitation of quantitative trait loci (QTL) mapping is that accuracy of determining QTL position and effects are largely determined by population size. Despite the importance of this concept, known as the "Beavis effect there has generally been a lack of understanding by molecular geneticists and breeders. One possible ...

  9. The effect of iterative reconstruction on computed tomography assessment of emphysema, air trapping and airway dimensions

    NARCIS (Netherlands)

    Mets, Onno M.; Willemink, Martin J.; de Kort, Freek P. L.; Mol, Christian P.; Leiner, Tim; Oudkerk, Matthijs; Prokop, Mathias; de Jong, Pim A.

    2012-01-01

    To determine the influence of iterative reconstruction (IR) on quantitative computed tomography (CT) measurements of emphysema, air trapping, and airway wall and lumen dimensions, compared to filtered back-projection (FBP). Inspiratory and expiratory chest CTs of 75 patients (37 male, 38 female;

  10. Regorafenib effects on human colon carcinoma xenografts monitored by dynamic contrast-enhanced computed tomography with immunohistochemical validation.

    Directory of Open Access Journals (Sweden)

    Clemens C Cyran

    Full Text Available To investigate dynamic contrast-enhanced computed tomography for monitoring the effects of regorafenib on experimental colon carcinomas in rats by quantitative assessments of tumor microcirculation parameters with immunohistochemical validation.Colon carcinoma xenografts (HT-29 implanted subcutaneously in female athymic rats (n = 15 were imaged at baseline and after a one-week treatment with regorafenib by dynamic contrast-enhanced computed tomography (128-slice dual-source computed tomography. The therapy group (n = 7 received regorafenib daily (10 mg/kg bodyweight. Quantitative parameters of tumor microcirculation (plasma flow, mL/100 mL/min, endothelial permeability (PS, mL/100 mL/min, and tumor vascularity (plasma volume, % were calculated using a 2-compartment uptake model. Dynamic contrast-enhanced computed tomography parameters were validated with immunohistochemical assessments of tumor microvascular density (CD-31, tumor cell apoptosis (TUNEL, and proliferation (Ki-67.Regorafenib suppressed tumor vascularity (15.7±5.3 to 5.5±3.5%; p<0.05 and tumor perfusion (12.8±2.3 to 8.8±2.9 mL/100 mL/min; p = 0.063. Significantly lower microvascular density was observed in the therapy group (CD-31; 48±10 vs. 113±25, p<0.05. In regorafenib-treated tumors, significantly more apoptotic cells (TUNEL; 11844±2927 vs. 5097±3463, p<0.05 were observed. Dynamic contrast-enhanced computed tomography tumor perfusion and tumor vascularity correlated significantly (p<0.05 with microvascular density (CD-31; r = 0.84 and 0.66 and inversely with apoptosis (TUNEL; r = -0.66 and -0.71.Regorafenib significantly suppressed tumor vascularity (plasma volume quantified by dynamic contrast-enhanced computed tomography in experimental colon carcinomas in rats with good-to-moderate correlations to an immunohistochemical gold standard. Tumor response biomarkers assessed by dynamic contrast-enhanced computed tomography may be a promising future

  11. Effective Heart Disease Detection Based on Quantitative Computerized Traditional Chinese Medicine Using Representation Based Classifiers

    Directory of Open Access Journals (Sweden)

    Ting Shu

    2017-01-01

    Full Text Available At present, heart disease is the number one cause of death worldwide. Traditionally, heart disease is commonly detected using blood tests, electrocardiogram, cardiac computerized tomography scan, cardiac magnetic resonance imaging, and so on. However, these traditional diagnostic methods are time consuming and/or invasive. In this paper, we propose an effective noninvasive computerized method based on facial images to quantitatively detect heart disease. Specifically, facial key block color features are extracted from facial images and analyzed using the Probabilistic Collaborative Representation Based Classifier. The idea of facial key block color analysis is founded in Traditional Chinese Medicine. A new dataset consisting of 581 heart disease and 581 healthy samples was experimented by the proposed method. In order to optimize the Probabilistic Collaborative Representation Based Classifier, an analysis of its parameters was performed. According to the experimental results, the proposed method obtains the highest accuracy compared with other classifiers and is proven to be effective at heart disease detection.

  12. Quantitative analysis of adenosine A1 receptors in human brain using positron emission tomography and [1 -methyl-11C]8-dicyclopropylmethyl-1-methyl-3-propylxanthine

    International Nuclear Information System (INIS)

    Kimura, Yuichi; Ishii, Kenji; Fukumitsu, Nobuyoshi; Oda, Keiichi; Sasaki, Toru; Kawamura, Kazunori; Ishiwata, Kiichi

    2004-01-01

    Fully quantitative analysis of the adenosine A 1 receptor (A1R) in the brain with 11 C-MPDX and positron emission tomography is reported. The kinetics is described using a two-tissue three-compartment model, and estimated binding potentials correspond well with the estimates made by Logan plot. The image of the binding potential of the MPDX is physiologically reasonable. We conclude that MPDX is applicable to the visualization of the A1Rs in the brain with Logan plot

  13. Novel X-ray phase-contrast tomography method for quantitative studies of heat induced structural changes in meat

    DEFF Research Database (Denmark)

    Miklos, Rikke; Nielsen, Mikkel Schou; Einarsdottir, Hildur

    2014-01-01

    The objective of this study was to evaluate the use of X-ray phase-contrast tomography combined with 3D image segmentation to investigate the heat induced structural changes in meat. The measurements were performed at the Swiss synchrotron radiation light source using a grating interferometric...... and separated into a water phase and a gel phase formed by the sarcoplasmic proteins in the exudate. The results show that X-ray phase contrast tomography offers unique possibilities in studies both the meat structure and the different meat component such as water, fat, connective tissue and myofibrils...

  14. Quantitative evaluation of native lung hyperinflation after single lung transplantation for emphysema using three-dimensional computed tomography volumetry.

    Science.gov (United States)

    Motoyama, H; Chen, F; Ohsumi, A; Hijiya, K; Takahashi, M; Ohata, K; Yamada, T; Sato, M; Aoyama, A; Bando, T; Date, H

    2014-04-01

    Although double lung transplantation is performed more frequently for emphysema, single lung transplantation (SLT) continues to be performed owing to limited donor organ availability. Native lung hyperinflation (NLH) is a unique complication following SLT for emphysema. Three-dimensional computed tomography (3D-CT) volumetry has been introduced into the field of lung transplantation, which we used to assess NLH in emphysema patients undergoing SLT. The primary purpose of this study was to confirm the effectiveness of 3D-CT volumetry in the evaluation of NLH following SLT for emphysema. In 5 emphysema patients undergoing SLT at Kyoto University Hospital, 3D-CT volumetry data, pulmonary function test results, and clinical and radiological findings were retrospectively evaluated. Three patients did not develop a significant mediastinal shift, whereas the other 2 patients developed a mediastinal shift. In the 3 patients without a mediastinal shift, 3D-CT volumetry did not show a significant increase in native lung volume. These patients had a history of sternotomy prior to lung transplantation and firm adhesion on the mediastinal side was detected during lung transplantation. One of 2 patients with a mediastinal shift developed severe dyspnea with significantly decreased pulmonary function, and 3D-CT volumetry showed a significant increase in the native lung volume. However, the other patient did not show any dyspnea and his native lung volume decreased postoperatively (preoperatively to 6 months postoperatively: +981 mL and -348 mL, respectively). Although bilateral lung transplantation has become preferable for emphysema patients owing to postoperative NLH with SLT, patients with a history of sternotomy prior to lung transplantation might be good candidates for SLT. 3D-CT volumetry may be a useful method for detection of NLH. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. A quantitative index of regional blood flow in canine myocardium derived noninvasively with N-13 ammonia and dynamic positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Nienaber, C.A.; Ratib, O.; Gambhir, S.S.; Krivokapich, J.; Huang, S.C.; Phelps, M.E.; Schelbert, H.R. (Univ. of California, Los Angeles School of Medicine (USA))

    1991-01-01

    To derive a quantitative index of regional myocardial blood flow, the arterial input function of the flow tracer N-13 ammonia and the regional myocardial N-13 activity concentrations were noninvasively determined in 29 experiments in eight dogs. N-13 ammonia was administered intravenously and cross-sectional images were acquired dynamically using an ECAT III positron emission tomograph with an effective in-plane resolution of 13.46 mm full-width half-maximum. Time-activity curves were derived from the serial images by assigning regions of interest to the left ventricular myocardium and left ventricular blood pool. Tracer net extractions were estimated from the myocardial time-activity concentrations at various times after tracer injection and the integral of the arterial input function. Myocardial blood flow was altered by intravenous dipyridamole, morphine, propranolol and partial or complete occlusion of the left anterior descending coronary artery, and ranged from 9 to 860 ml/min per 100 g. Estimates of tracer net extractions were most accurate when determined from the myocardial N-13 activity concentrations at 60 s divided by the integral of the arterial input function to that time. These estimates correlated with regional myocardial blood flows determined independently by the microsphere technique by y = x (1 - 0.64(e-114/x); SEE = 22.9; r = 0.94). First pass extraction fractions of N-13 ammonia determined noninvasively with this approach declined with higher flows in a nonlinear fashion and were similar to those determined invasively by direct intracoronary N-13 ammonia injections. The findings indicate that an accurate index of regional myocardial blood flow can be obtained noninvasively by high temporal sampling of arterial and myocardial tracer activity concentrations with positron emission tomography.

  16. Disease activity and {sup 18}F-FDG uptake in organising pneumonia: semi-quantitative evaluation using computed tomography and positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Tateishi, Ukihide; Arai, Yasuaki [National Cancer Center Hospital, Division of Diagnostic Radiology, Tokyo (Japan); Hasegawa, Tadashi [Sapporo Medical University School of Medicine, Department of Clinical Pathology, Sapporo (Japan); Seki, Kunihiko [National Cancer Center Hospital, Pathology Division, Tokyo (Japan); Terauchi, Takashi; Moriyama, Noriyuki [Research Center for Cancer Prevention and Screening, National Cancer Center, Division of Radiology, Tokyo (Japan)

    2006-08-15

    Purpose: The present study was conducted to evaluate whether{sup 18}F-fluorodeoxyglucose positron emission tomography (FDG-PET) in combination with computed tomography (CT) reflects disease activity in patients with organising pneumonia.Methods: Eighty-eight subjects who were normal (n=66) or who had proven organising pneumonia (n=22) underwent FDG-PET and CT imaging. The subjects included 55 men and 33 women, ranging in age from 24 to 63 years (mean 47 years). PET and CT data sets were digitally fused using a conformational PET/CT fusion algorithm. All scans were evaluated independently by two chest radiologists who were unaware of other clinical data. The visual score, maximal and mean standardised uptake value (SUV), and maximal and mean lesion-to-normal tissue ratio (LNR) were calculated. The imaging results were compared with the laboratory and pulmonary function test results. The inflammatory cells in the lesions were quantified immunohistochemically. The visual score, maximal and mean SUV, and maximal and mean LNR of the patients with organising pneumonia were significantly higher than those of the normal subjects. The patients with air-space consolidation had a significantly higher SUV than those without air-space consolidation (mean{+-}SD 3.08{+-}0.39 vs 2.35{+-}0.56; p<0.05). The number of CD45{sup +} cells was positively correlated with the maximal SUV (r=0.632, p<0.01) and the maximal LNR (r=0.453, p<0.05). The number of CD8{sup +} T lymphocytes also showed positive correlations with the maximal SUV (r=0.540, p<0.01) and the maximal LNR (r=0.547, p<0.01). Patients with organising pneumonia have an enhanced FDG accumulation which reflects the degree of disease activity. (orig.)

  17. Disease activity and 18F-FDG uptake in organising pneumonia: semi-quantitative evaluation using computed tomography and positron emission tomography

    International Nuclear Information System (INIS)

    Tateishi, Ukihide; Arai, Yasuaki; Hasegawa, Tadashi; Seki, Kunihiko; Terauchi, Takashi; Moriyama, Noriyuki

    2006-01-01

    Purpose: The present study was conducted to evaluate whether 18 F-fluorodeoxyglucose positron emission tomography (FDG-PET) in combination with computed tomography (CT) reflects disease activity in patients with organising pneumonia.Methods: Eighty-eight subjects who were normal (n=66) or who had proven organising pneumonia (n=22) underwent FDG-PET and CT imaging. The subjects included 55 men and 33 women, ranging in age from 24 to 63 years (mean 47 years). PET and CT data sets were digitally fused using a conformational PET/CT fusion algorithm. All scans were evaluated independently by two chest radiologists who were unaware of other clinical data. The visual score, maximal and mean standardised uptake value (SUV), and maximal and mean lesion-to-normal tissue ratio (LNR) were calculated. The imaging results were compared with the laboratory and pulmonary function test results. The inflammatory cells in the lesions were quantified immunohistochemically. The visual score, maximal and mean SUV, and maximal and mean LNR of the patients with organising pneumonia were significantly higher than those of the normal subjects. The patients with air-space consolidation had a significantly higher SUV than those without air-space consolidation (mean±SD 3.08±0.39 vs 2.35±0.56; p + cells was positively correlated with the maximal SUV (r=0.632, p + T lymphocytes also showed positive correlations with the maximal SUV (r=0.540, p<0.01) and the maximal LNR (r=0.547, p<0.01). Patients with organising pneumonia have an enhanced FDG accumulation which reflects the degree of disease activity. (orig.)

  18. Effective dose range for dental cone beam computed tomography scanners

    International Nuclear Information System (INIS)

    Pauwels, Ruben; Beinsberger, Jilke; Collaert, Bruno; Theodorakou, Chrysoula; Rogers, Jessica; Walker, Anne; Cockmartin, Lesley; Bosmans, Hilde; Jacobs, Reinhilde; Bogaerts, Ria; Horner, Keith

    2012-01-01

    Objective: To estimate the absorbed organ dose and effective dose for a wide range of cone beam computed tomography scanners, using different exposure protocols and geometries. Materials and methods: Two Alderson Radiation Therapy anthropomorphic phantoms were loaded with LiF detectors (TLD-100 and TLD-100H) which were evenly distributed throughout the head and neck, covering all radiosensitive organs. Measurements were performed on 14 CBCT devices: 3D Accuitomo 170, Galileos Comfort, i-CAT Next Generation, Iluma Elite, Kodak 9000 3D, Kodak 9500, NewTom VG, NewTom VGi, Pax-Uni3D, Picasso Trio, ProMax 3D, Scanora 3D, SkyView, Veraviewepocs 3D. Effective dose was calculated using the ICRP 103 (2007) tissue weighting factors. Results: Effective dose ranged between 19 and 368 μSv. The largest contributions to the effective dose were from the remainder tissues (37%), salivary glands (24%), and thyroid gland (21%). For all organs, there was a wide range of measured values apparent, due to differences in exposure factors, diameter and height of the primary beam, and positioning of the beam relative to the radiosensitive organs. Conclusions: The effective dose for different CBCT devices showed a 20-fold range. The results show that a distinction is needed between small-, medium-, and large-field CBCT scanners and protocols, as they are applied to different indication groups, the dose received being strongly related to field size. Furthermore, the dose should always be considered relative to technical and diagnostic image quality, seeing that image quality requirements also differ for patient groups. The results from the current study indicate that the optimisation of dose should be performed by an appropriate selection of exposure parameters and field size, depending on the diagnostic requirements.

  19. Morphological image processing for quantitative shape analysis of biomedical structures: effective contrast enhancement

    International Nuclear Information System (INIS)

    Kimori, Yoshitaka

    2013-01-01

    A contrast enhancement approach utilizing a new type of mathematical morphology called rotational morphological processing is introduced. The method is quantitatively evaluated and then applied to some medical images. Image processing methods significantly contribute to visualization of images captured by biomedical modalities (such as mammography, X-ray computed tomography, magnetic resonance imaging, and light and electron microscopy). Quantitative interpretation of the deluge of complicated biomedical images, however, poses many research challenges, one of which is to enhance structural features that are scarcely perceptible to the human eye. This study introduces a contrast enhancement approach based on a new type of mathematical morphology called rotational morphological processing. The proposed method is applied to medical images for the enhancement of structural features. The effectiveness of the method is evaluated quantitatively by the contrast improvement ratio (CIR). The CIR of the proposed method is 12.1, versus 4.7 and 0.1 for two conventional contrast enhancement methods, clearly indicating the high contrasting capability of the method

  20. A synchrotron-based local computed tomography combined with data-constrained modelling approach for quantitative analysis of anthracite coal microstructure

    International Nuclear Information System (INIS)

    Chen, Wen Hao; Yang, Sam Y. S.; Xiao, Ti Qiao; Mayo, Sherry C.; Wang, Yu Dan; Wang, Hai Peng

    2014-01-01

    A quantitative local computed tomography combined with data-constrained modelling has been developed. The method could improve distinctly the spatial resolution and the composition resolution in a sample larger than the field of view, for quantitative characterization of three-dimensional distributions of material compositions and void. Quantifying three-dimensional spatial distributions of pores and material compositions in samples is a key materials characterization challenge, particularly in samples where compositions are distributed across a range of length scales, and where such compositions have similar X-ray absorption properties, such as in coal. Consequently, obtaining detailed information within sub-regions of a multi-length-scale sample by conventional approaches may not provide the resolution and level of detail one might desire. Herein, an approach for quantitative high-definition determination of material compositions from X-ray local computed tomography combined with a data-constrained modelling method is proposed. The approach is capable of dramatically improving the spatial resolution and enabling finer details within a region of interest of a sample larger than the field of view to be revealed than by using conventional techniques. A coal sample containing distributions of porosity and several mineral compositions is employed to demonstrate the approach. The optimal experimental parameters are pre-analyzed. The quantitative results demonstrated that the approach can reveal significantly finer details of compositional distributions in the sample region of interest. The elevated spatial resolution is crucial for coal-bed methane reservoir evaluation and understanding the transformation of the minerals during coal processing. The method is generic and can be applied for three-dimensional compositional characterization of other materials

  1. Quantitative analysis of orthopedic metal artefact reduction in 64-slice computed tomography scans in large head metal-on-metal total hip replacement, a phantom study

    NARCIS (Netherlands)

    Boomsma, Martijn F.; Warringa, Niek; Edens, Mireille A.; Mueller, Dirk; Ettema, Harmen B.; Verheyen, Cees C. P. M.; Maas, Mario

    2016-01-01

    Purpose: Quantification of the effect of O-MAR on decreasing metal artefacts caused by large head metal on metal total hip arthroplasty (MoM THA) in a dedicated phantom setup of the hip. Background: Pathological reactions of the hip capsule on Computed tomography (CT) can be difficult to diagnose

  2. Quantitative computed tomography analysis of the airways in patients with cystic fibrosis using automated software: correlation with spirometry in the evaluation of severity

    International Nuclear Information System (INIS)

    Santos, Marcel Koenigkam; Cruvinel, Danilo Lemos; Menezes, Marcelo Bezerra de; Teixeira, Sara Reis; Vianna, Elcio de Oliveira; Elias Junior, Jorge; Martinez, Jose Antonio Baddini

    2016-01-01

    Objective: To perform a quantitative analysis of the airways using automated software, in computed tomography images of patients with cystic fibrosis, correlating the results with spirometric findings. Materials and methods: Thirty-four patients with cystic fibrosis were studied-20 males and 14 females; mean age 18 ± 9 years - divided into two groups according to the spirometry findings: group I (n = 21), without severe airflow obstruction (forced expiratory volume in first second [FEV1] > 50% predicted), and group II (n = 13), with severe obstruction (FEV1 ≤ 50% predicted). The following tracheobronchial tree parameters were obtained automatically: bronchial diameter, area, thickness, and wall attenuation. Results: On average, 52 bronchi per patient were studied. The number of bronchi analyzed was higher in group II. The correlation with spirometry findings, especially between the relative wall thickness of third to eighth bronchial generation and predicted FEV1, was better in group I. Conclusion: Quantitative analysis of the airways by computed tomography can be useful for assessing disease severity in cystic fibrosis patients. In patients with severe airflow obstruction, the number of bronchi studied by the method is higher, indicating more bronchiectasis. In patients without severe obstruction, the relative bronchial wall thickness showed a good correlation with the predicted FEV1. (author)

  3. Quantitative computed tomography analysis of the airways in patients with cystic fibrosis using automated software: correlation with spirometry in the evaluation of severity

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Marcel Koenigkam; Cruvinel, Danilo Lemos; Menezes, Marcelo Bezerra de; Teixeira, Sara Reis; Vianna, Elcio de Oliveira; Elias Junior, Jorge; Martinez, Jose Antonio Baddini, E-mail: marcelk46@yahoo.com.br [Universidade de Sao Paulo (HC/FMRP/USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina

    2016-11-15

    Objective: To perform a quantitative analysis of the airways using automated software, in computed tomography images of patients with cystic fibrosis, correlating the results with spirometric findings. Materials and methods: Thirty-four patients with cystic fibrosis were studied-20 males and 14 females; mean age 18 ± 9 years - divided into two groups according to the spirometry findings: group I (n = 21), without severe airflow obstruction (forced expiratory volume in first second [FEV1] > 50% predicted), and group II (n = 13), with severe obstruction (FEV1 ≤ 50% predicted). The following tracheobronchial tree parameters were obtained automatically: bronchial diameter, area, thickness, and wall attenuation. Results: On average, 52 bronchi per patient were studied. The number of bronchi analyzed was higher in group II. The correlation with spirometry findings, especially between the relative wall thickness of third to eighth bronchial generation and predicted FEV1, was better in group I. Conclusion: Quantitative analysis of the airways by computed tomography can be useful for assessing disease severity in cystic fibrosis patients. In patients with severe airflow obstruction, the number of bronchi studied by the method is higher, indicating more bronchiectasis. In patients without severe obstruction, the relative bronchial wall thickness showed a good correlation with the predicted FEV1. (author)

  4. Effects of computed tomography contrast medium factors on contrast enhancement

    International Nuclear Information System (INIS)

    Terasawa, Kazuaki; Hatcho, Atsushi; Okuda, Itsuko

    2011-01-01

    The various nonionic iodinated contrast media used in contrast computed tomography (CT) studies differ in terms of their composition, characteristics, and iodine concentration (mgI/ml), as well as the volume injected (ml). Compared with ionic iodinated contrast media, nonionic iodinated contrast media are low-osmolar agents, with different agents having different osmotic pressures. Using a custom-made phantom incorporating a semipermeable membrane, the osmotic flow rate (hounsfield unit (HU)/s) could easily be measured based on the observed increase in CT numbers, and the relationship between the osmotic pressure and the osmotic flow rate could be obtained (r 2 =0.84). In addition, taking the effects of patient size into consideration, the levels of contrast enhancement in the abdominal aorta (AA) and inferior vena cava (IVC) were compared among four types of CT contrast medium. The results showed differences in contrast enhancement in the IVC during the equilibrium phase depending on the type of contrast medium used. It was found that the factors responsible for the differences observed in enhancement in the IVC were the osmotic flow rate and the volume of the blood flow pathways in the circulatory system. It is therefore considered that the reproducibility of contrast enhancement is likely to be reduced in the examination of parenchymal organs, in which scanning must be performed during the equilibrium phase, even if the amount of iodine injected per unit body weight (mgI/kg) is maintained at a specified level. (author)

  5. Mycosis fungoides: Positron emission tomography/computed tomography in staging and monitoring the effect of therapy

    International Nuclear Information System (INIS)

    D’Souza, Maria Mathew; D’Souza, Paschal; Sharma, Rajnish; Jaimini, Abhinav; Mondal, Anupam

    2015-01-01

    A 58-year-old woman, diagnosed as a case of mycosis fungoides (MF), underwent [18F]-fluoro-D-glucose positron emission tomography/computed tomography (FDG PET/CT) examination. The study revealed intense FDG uptake in a large ulceroproliferative right thigh lesion, indurated plaques in the chest wall and left thigh, along with multiple sites of cutaneous involvement, axillary and inguinal lymphadenopathy. The patient underwent chemotherapy with CHOP regimen, radiotherapy for the right thigh lesion, along with topical corticosteroids and emollients for the disseminated cutaneous involvement. Repeat [18F]-FDG PET/CT study performed a year later, showed near complete disease regression specifically of the ulceroproliferative lesion and indurated cutaneous plaques, no change in lymphadenopathy, and a subtle diffuse progression of the remaining cutaneous lesions. A multidisciplinary approach to the diagnosis, staging and treatment of MF has long been suggested for optimizing outcomes from management of patients with this disease. This case highlights the potential role of incorporating PET/CT as a single modality imaging technique in the staging and assessment of response to therapy

  6. Comparison of panoramic radiography and cone-beam computed tomography for qualitative and quantitative measurements regarding localization of permanent impacted maxillary canines

    Directory of Open Access Journals (Sweden)

    Çiğdem Sarıkır

    2017-01-01

    Full Text Available Objective: The purpose of this retrospective study was to compare the correlation between digital panoramic radiography (DPR and cone-beam computed tomography (CBCT evaluations for localization of impacted permanent maxillary canines (IPMCs and for other qualitative and quantitative parameters. Materials and Method: DPR and CBCT images of 60 patients (17 men and 43 women were examined independently by two observers. Correlations between DPR and CBCT images were evaluated regarding qualitative (bucco-palatal positioning of IPMCs, morphology and presence of root resorption of adjacent permanent lateral incisors, and contact relationship between IPMCs and adjacent permanent lateral incisors and quantitative (angle measurements variables. All evaluations were repeated 1 month later by each observer. Chi-square and t-tests were used for statistical analysis. Kappa statistics were used to assess intra- and interobserver agreement (Cohen’s κ. Results: No correlation was observed for determination of bucco-palatal positioning of IPMCs between DPR and CBCT images (p>0.05. Correlations were observed for other qualitative variables (p<0.05. Differences between DPR and CBCT images were seen for all examined quantitative variables (p<0.01. Intra- and interobserver agreements were substantial to almost-perfect. Conclusion: No significant correlation was found between DPR and CBCT images for determination of bucco-palatal positioning of IPMCs. All quantitative measurements performed on DPR and CBCT images significantly differed from each other.

  7. Quantitative estimation of viable myocardium in the infarcted zone by infarct-redistribution map from images of exercise thallium-201 emission computed tomography

    International Nuclear Information System (INIS)

    Sekiai, Yasuhiro

    1988-01-01

    To evaluate, quantitatively, the viable myocardium in the infarcted zone, we invented the infarct-redistribution map which is produced from images of exercise thallium-201 emission computed tomography performed on 10 healthy subjects and 20 patients with myocardial infarction. The map displayed a left ventricle in which the infarcted area both with and without redistribution, the redistribution area without infarction, and normal perfusion area were shown separated in same screen. In these circumstances, the nonredistribution infarct lesion was found as being surrounded by the redistribution area. Indices of infarct and redistribution extent (defect score, % defect, redistribution ratio (RR) and redistribution index (RI)), were induced from the map and were used for quantitative analysis of the redistribution area and as the basis for comparative discussion regarding regional wall motion of the left ventricle. The quantitative indices of defect score, % defect, RR and RI were consistent with the visual assessment of planar images in detecting the extent of redistribution. Furthermore, defect score and % defect had an inverted linear relationship with % shortening (r = -0.573; p < 0.05, r = -0.536; p < 0.05, respectively), and RI had a good linear relationship with % shortening (r = 0.669; p < 0.01). We conclude that the infarct-redistribution map accurately reflects the myocardial viability and therefore may be useful for quantitative estimation of viable myocardium in the infarcted zone. (author)

  8. Quantitation of size of myocardial infarctions by computerized transmission tomography. Comparison with hot-spot and cold-spot radionuclide scans

    International Nuclear Information System (INIS)

    Gerber, K.H.; Higgins, C.B.

    1983-01-01

    The current study evaluated the ability to quantitate the volume of myocardial infarctions when they are outlined by intravenously administered contrast media in the myocardial perfusion phase and in the phase of delayed contrast enhancement of the infarct. Quantitation by contrast media was assessed from computerized transmission tomography (CTT) scans of the ex situ heart and compared with quantitation by technetium-99m (/sup 99m/Tc)pyrophosphate (/sup 99m/Tc PYP) and thallium-201 (201Tl) scans of the same ex situ hearts. True volume was defined by histochemical morphometry. CTT during the contrast perfusion phase uniformly underestimated infarct size but had a good correlation with true volume. CTT during enhancement phase correlated closely with true volume (r . 0.98) and most precisely measured true size (y . 1.06 X 0.23). The /sup 99m/Tc PYP scan overestimated infarct volume (predictive overestimation of 6 to 199%) but had a good correlation with true volume. 201Tl underestimated infarct volume but correlated well with true volume. Thus, quantitation of infarct volume from CTT scans performed during either the perfusion or infarct enhancement phase after intravenous contrast media provides a good estimate of true infarct volume. Delineation of the infarct by contrast media in the ex situ heart is more precise during the phase of delayed enhancement of the infarct

  9. Quantitative Assessment of Optical Coherence Tomography Imaging Performance with Phantom-Based Test Methods And Computational Modeling

    Science.gov (United States)

    Agrawal, Anant

    Optical coherence tomography (OCT) is a powerful medical imaging modality that uniquely produces high-resolution cross-sectional images of tissue using low energy light. Its clinical applications and technological capabilities have grown substantially since its invention about twenty years ago, but efforts have been limited to develop tools to assess performance of OCT devices with respect to the quality and content of acquired images. Such tools are important to ensure information derived from OCT signals and images is accurate and consistent, in order to support further technology development, promote standardization, and benefit public health. The research in this dissertation investigates new physical and computational models which can provide unique insights into specific performance characteristics of OCT devices. Physical models, known as phantoms, are fabricated and evaluated in the interest of establishing standardized test methods to measure several important quantities relevant to image quality. (1) Spatial resolution is measured with a nanoparticle-embedded phantom and model eye which together yield the point spread function under conditions where OCT is commonly used. (2) A multi-layered phantom is constructed to measure the contrast transfer function along the axis of light propagation, relevant for cross-sectional imaging capabilities. (3) Existing and new methods to determine device sensitivity are examined and compared, to better understand the detection limits of OCT. A novel computational model based on the finite-difference time-domain (FDTD) method, which simulates the physics of light behavior at the sub-microscopic level within complex, heterogeneous media, is developed to probe device and tissue characteristics influencing the information content of an OCT image. This model is first tested in simple geometric configurations to understand its accuracy and limitations, then a highly realistic representation of a biological cell, the retinal

  10. Multifactorial Optimization of Contrast-Enhanced Nanofocus Computed Tomography for Quantitative Analysis of Neo-Tissue Formation in Tissue Engineering Constructs.

    Directory of Open Access Journals (Sweden)

    Maarten Sonnaert

    Full Text Available To progress the fields of tissue engineering (TE and regenerative medicine, development of quantitative methods for non-invasive three dimensional characterization of engineered constructs (i.e. cells/tissue combined with scaffolds becomes essential. In this study, we have defined the most optimal staining conditions for contrast-enhanced nanofocus computed tomography for three dimensional visualization and quantitative analysis of in vitro engineered neo-tissue (i.e. extracellular matrix containing cells in perfusion bioreactor-developed Ti6Al4V constructs. A fractional factorial 'design of experiments' approach was used to elucidate the influence of the staining time and concentration of two contrast agents (Hexabrix and phosphotungstic acid and the neo-tissue volume on the image contrast and dataset quality. Additionally, the neo-tissue shrinkage that was induced by phosphotungstic acid staining was quantified to determine the operating window within which this contrast agent can be accurately applied. For Hexabrix the staining concentration was the main parameter influencing image contrast and dataset quality. Using phosphotungstic acid the staining concentration had a significant influence on the image contrast while both staining concentration and neo-tissue volume had an influence on the dataset quality. The use of high concentrations of phosphotungstic acid did however introduce significant shrinkage of the neo-tissue indicating that, despite sub-optimal image contrast, low concentrations of this staining agent should be used to enable quantitative analysis. To conclude, design of experiments allowed us to define the most optimal staining conditions for contrast-enhanced nanofocus computed tomography to be used as a routine screening tool of neo-tissue formation in Ti6Al4V constructs, transforming it into a robust three dimensional quality control methodology.

  11. Effects of Hyperthyroidism on Coronary Artery Disease: A Computed Tomography Angiography Study.

    Science.gov (United States)

    Beyer, Christoph; Plank, Fabian; Friedrich, Guy; Wildauer, Matthias; Feuchtner, Gudrun

    2017-10-01

    Changes in thyroid hormone concentration can negatively affect the cardiovascular system. Subclinical hyperthyroidism has been linked to an increase of cardiovascular heart disease, however, clinical effects and significance are still uncertain. Therefore, we analyzed coronary computed tomography angiographies of patients with overt and subclinical hyperthyroidism for quantitative parameters and plaque morphology. Seven hundred forty-four (47.1% female) patients who underwent coronary computed tomography angiography were stratified into 3 groups: 51 patients with overt, 74 patients with subclinical hyperthyroidism, and 619 patients with euthyroidism. Analysis included grades of stenosis (no stenosis = 0, mild 70%) and plaque types (noncalcified, mixed, and calcified), segment involvement score (SIS), noncalcified SIS, and high-risk plaque features (napkin ring sign, low attenuation plaque, spotty calcifications, positive remodelling). Patients with overt and subclinical hyperthyroidism had more high-grade stenoses (39.2% vs 37.8% vs 24.2%; P = 0.007) and a higher coronary calcium score (456.5 vs 199.5 vs 155.9; P hyperthyroidism, followed by those with subclinical hyperthyroidism, had the most high-risk plaque features: napkin ring (21.6% vs 9.5% vs 6.0%, P hyperthyroid patients. Patients with subclinical and overt hyperthyroidism showed more high-grade coronary stenoses, plaque burden, and high-risk plaque features than patients with euthyroidism, which indicates that an increase of thyroid hormones might lead to coronary vascular degeneration and plaque instability. Copyright © 2017 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

  12. Spectral Domain Optical Coherence Tomography in Glaucoma: Qualitative and Quantitative Analysis of the Optic Nerve Head and Retinal Nerve Fiber Layer (An AOS Thesis)

    Science.gov (United States)

    Chen, Teresa C.

    2009-01-01

    Purpose: To demonstrate that video-rate spectral domain optical coherence tomography (SDOCT) can qualitatively and quantitatively evaluate optic nerve head (ONH) and retinal nerve fiber layer (RNFL) glaucomatous structural changes. To correlate quantitative SDOCT parameters with disc photography and visual fields. Methods: SDOCT images from 4 glaucoma eyes (4 patients) with varying stages of open-angle glaucoma (ie, early, moderate, late) were qualitatively contrasted with 2 age-matched normal eyes (2 patients). Of 61 other consecutive patients recruited in an institutional setting, 53 eyes (33 patients) met inclusion/exclusion criteria for quantitative studies. Images were obtained using two experimental SDOCT systems, one utilizing a superluminescent diode and the other a titanium:sapphire laser source, with axial resolutions of about 6 μm and 3 μm, respectively. Results: Classic glaucomatous ONH and RNFL structural changes were seen in SDOCT images. An SDOCT reference plane 139 μm above the retinal pigment epithelium yielded cup-disc ratios that best correlated with masked physician disc photography cup-disc ratio assessments. The minimum distance band, a novel SDOCT neuroretinal rim parameter, showed good correlation with physician cup-disc ratio assessments, visual field mean deviation, and pattern standard deviation (P values range, .0003–.024). RNFL and retinal thickness maps correlated well with disc photography and visual field testing. Conclusions: To our knowledge, this thesis presents the first comprehensive qualitative and quantitative evaluation of SDOCT images of the ONH and RNFL in glaucoma. This pilot study provides basis for developing more automated quantitative SDOCT-specific glaucoma algorithms needed for future prospective multicenter national trials. PMID:20126502

  13. SedCT: MATLAB™ tools for standardized and quantitative processing of sediment core computed tomography (CT) data collected using a medical CT scanner

    Science.gov (United States)

    Reilly, B. T.; Stoner, J. S.; Wiest, J.

    2017-08-01

    Computed tomography (CT) of sediment cores allows for high-resolution images, three-dimensional volumes, and down core profiles. These quantitative data are generated through the attenuation of X-rays, which are sensitive to sediment density and atomic number, and are stored in pixels as relative gray scale values or Hounsfield units (HU). We present a suite of MATLAB™ tools specifically designed for routine sediment core analysis as a means to standardize and better quantify the products of CT data collected on medical CT scanners. SedCT uses a graphical interface to process Digital Imaging and Communications in Medicine (DICOM) files, stitch overlapping scanned intervals, and create down core HU profiles in a manner robust to normal coring imperfections. Utilizing a random sampling technique, SedCT reduces data size and allows for quick processing on typical laptop computers. SedCTimage uses a graphical interface to create quality tiff files of CT slices that are scaled to a user-defined HU range, preserving the quantitative nature of CT images and easily allowing for comparison between sediment cores with different HU means and variance. These tools are presented along with examples from lacustrine and marine sediment cores to highlight the robustness and quantitative nature of this method.

  14. Differentiation between Birt–Hogg–Dubé syndrome and lymphangioleiomyomatosis: Quantitative analysis of pulmonary cysts on computed tomography of the chest in 66 females

    International Nuclear Information System (INIS)

    Tobino, Kazunori; Hirai, Toyohiro; Johkoh, Takeshi; Kurihara, Masatoshi; Fujimoto, Kiminori; Tomiyama, Noriyuki; Mishima, Michiaki; Takahashi, Kazuhisa; Seyama, Kuniaki

    2012-01-01

    Backgrounds: Since Birt–Hogg–Dubé syndrome (BHDS) and lymphangioleiomyomatosis (LAM) share some clinical manifestations (multiple pulmonary cysts with pneumothorax, renal tumors, and sometimes skin lesions), the differential diagnosis of the two diseases becomes problem especially in female patients. This study aims to quantify pulmonary cysts in computed tomography (CT) of females with BHDS and those with LAM and also to identify the independent parameters for differentiating the two diseases. Methods: Fourteen patients with BHDS and 52 with LAM were studied. In CT scans, lung fields were defined as areas with fewer than −200 Hounsfield units (HU) and pulmonary cysts as areas consisting of 10 or more consecutive pixels with fewer than −960 HU. The extent, number, size and circularity of cysts were calculated by using hand-made software and compared between the two diseases. Moreover, the lung fields were divided into six zones and analyzed for the distribution of cysts. Finally, a stepwise discriminant analysis employing quantitative measurements of cysts and clinical features was performed. Results: The two diseases were significantly different in all quantitative measurements of cysts. Stepwise discriminant analysis accepted the following four variables: the family history of pneumothorax within the second degree relatives, lower-medial zone predominance of cysts, diffusing capacity and mean size of cysts in this order. Conclusion: The quantitative characteristics of pulmonary cysts are significantly different between BHDS and LAM. The independent parameters for differentiating the two diseases are the family history of pneumothorax, zonal predominance of cysts, diffusing capacity and size of cysts.

  15. The effect of Compton scattering on quantitative SPECT imaging

    International Nuclear Information System (INIS)

    Beck, J.W.; Jaszczak, R.J.; Starmer, C.F.

    1982-01-01

    A Monte Carlo code has been developed to simulate the response of a SPECT system. The accuracy of the code has been verified and has been used in this research to study and illustrate the effects of Compton scatter on quantitative SPECT measurements. The effects of Compton scattered radiation on gamma camera response have been discussed by several authors, and will be extended to rotating gamma camera SPECT systems. The unique feature of this research includes the pictorial illustration of the Compton scattered and the unscattered components of the photopeak data on SPECT imaging by simulating phantom studies with and without Compton scatter

  16. Quantitative effects of cyanogenesis on an adapted herbivore.

    Science.gov (United States)

    Ballhorn, D J; Heil, M; Pietrowski, A; Lieberei, R

    2007-12-01

    Plant cyanogenesis means the release of gaseous hydrogen cyanide (HCN) in response to cell damage and is considered as an effective defense against generalist herbivores. In contrast, specialists are generally believed not to be affected negatively by this trait. However, quantitative data on long-term effects of cyanogenesis on specialists are rare. In this study, we used lima bean accessions (Fabaceae: Phaseolus lunatus L.) with high quantitative variability of cyanogenic features comprising cyanogenic potential (HCNp; concentration of cyanogenic precursors) and cyanogenic capacities (HCNc; release of gaseous HCN per unit time). In feeding trials, we analyzed performance of herbivorous Mexican bean beetle (Coleoptera: Coccinellidae: Epilachna varivestis Mulsant) on selected lines characterized by high (HC-plants) and low HCNp (LC-plants). Larval and adult stages of this herbivore feed on a narrow range of legumes and prefer cyanogenic lima bean as host plant. Nevertheless, we found that performance of beetles (larval weight gain per time and body mass of adult beetles) was significantly affected by lima bean HCNp: Body weight decreased and developmental period of larvae and pupae increased on HC-plants during the first generation of beetles and then remained constant for four consecutive generations. In addition, we found continuously decreasing numbers of eggs and larval hatching as inter-generational effects on HC-plants. In contrast to HC-plants, constantly high performance was observed among four generations on LC-plants. Our results demonstrate that Mexican bean beetle, although preferentially feeding on lima bean, is quantitatively affected by the HCNp of its host plant. Effects can only be detected when considering more than one generation. Thus, cyanide-containing precursors can have negative effects even on herbivores adapted to feed on cyanogenic plants.

  17. Quantitative transmission electron microscopy and atom probe tomography study of Ag-dependent precipitation of Ω phase in Al-Cu-Mg alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Song; Ying, Puyou [Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083 (China); School of Material Science and Engineering, Central South University, Changsha 410083 (China); Liu, Zhiyi, E-mail: liuzhiyi@csu.edu.cn [Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083 (China); School of Material Science and Engineering, Central South University, Changsha 410083 (China); Wang, Jian; Li, Junlin [Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083 (China); School of Material Science and Engineering, Central South University, Changsha 410083 (China)

    2017-02-27

    The close association between the Ω precipitation and various Ag additions is systematically investigated by quantitative transmission electron microscopy and atom probe tomography analysis. Our results suggest that the precipitation of Ω phase is strongly dependent on Ag variations. Increasing the bulk Ag content favors a denser Ω precipitation and hence leads to a greater age-hardening response of Al-Cu-Mg-Ag alloy. This phenomenon, as proposed by proximity histograms, is directly related to the greater abundance of Ag solutes within Ω precursors. This feature lowers its nucleation barrier and increases the nucleation rate of Ω phase, finally contributes to the enhanced Ω precipitation. Also, it is noted that increasing Ag remarkably restricts the precipitation of θ' phase.

  18. Nondestructive and quantitative characterization of TRU and LLW mixed-waste using active and passive gamma-ray spectrometry and computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Camp, D.C.; Martz, H.E.

    1991-11-12

    The technology being proposed by LLNL is an Active and Passive Computed Tomography (A P CT) Drum Scanner for contact-handled (CH) wastes. It combines the advantages offered by two well-developed nondestructive assay technologies: gamma-ray spectrometry and computed tomography (CT). Coupled together, these two technologies offer to nondestructively and quantitatively characterize mixed- wastes forms. Gamma-ray spectroscopy uses one or more external radiation detectors to passively and nondestructively measure the energy spectrum emitted from a closed container. From the resulting spectrum one can identify most radioactivities detected, be they transuranic isotopes, mixed-fission products, activation products or environmental radioactivities. Spectral libraries exist at LLNL for all four. Active (A) or transmission CT is a well-developed, nondestructive medical and industrial technique that uses an external-radiation beam to map regions of varying attenuation within a container. Passive (P) or emission CT is a technique mainly developed for medical application, e.g., single-photon emission CT. Nondestructive industrial uses of PCT are under development and just coming into use. This report discuses work on the A P CT Drum Scanner at LLNL.

  19. Nondestructive and quantitative characterization of TRU and LLW mixed-waste using active and passive gamma-ray spectrometry and computed tomography

    International Nuclear Information System (INIS)

    Camp, D.C.; Martz, H.E.

    1991-01-01

    The technology being proposed by LLNL is an Active and Passive Computed Tomography (A ampersand P CT) Drum Scanner for contact-handled (CH) wastes. It combines the advantages offered by two well-developed nondestructive assay technologies: gamma-ray spectrometry and computed tomography (CT). Coupled together, these two technologies offer to nondestructively and quantitatively characterize mixed- wastes forms. Gamma-ray spectroscopy uses one or more external radiation detectors to passively and nondestructively measure the energy spectrum emitted from a closed container. From the resulting spectrum one can identify most radioactivities detected, be they transuranic isotopes, mixed-fission products, activation products or environmental radioactivities. Spectral libraries exist at LLNL for all four. Active (A) or transmission CT is a well-developed, nondestructive medical and industrial technique that uses an external-radiation beam to map regions of varying attenuation within a container. Passive (P) or emission CT is a technique mainly developed for medical application, e.g., single-photon emission CT. Nondestructive industrial uses of PCT are under development and just coming into use. This report discuses work on the A ampersand P CT Drum Scanner at LLNL

  20. Multicenter study of quantitative computed tomography analysis using a computer-aided three-dimensional system in patients with idiopathic pulmonary fibrosis.

    Science.gov (United States)

    Iwasawa, Tae; Kanauchi, Tetsu; Hoshi, Toshiko; Ogura, Takashi; Baba, Tomohisa; Gotoh, Toshiyuki; Oba, Mari S

    2016-01-01

    To evaluate the feasibility of automated quantitative analysis with a three-dimensional (3D) computer-aided system (i.e., Gaussian histogram normalized correlation, GHNC) of computed tomography (CT) images from different scanners. Each institution's review board approved the research protocol. Informed patient consent was not required. The participants in this multicenter prospective study were 80 patients (65 men, 15 women) with idiopathic pulmonary fibrosis. Their mean age was 70.6 years. Computed tomography (CT) images were obtained by four different scanners set at different exposures. We measured the extent of fibrosis using GHNC, and used Pearson's correlation analysis, Bland-Altman plots, and kappa analysis to directly compare the GHNC results with manual scoring by radiologists. Multiple linear regression analysis was performed to determine the association between the CT data and forced vital capacity (FVC). For each scanner, the extent of fibrosis as determined by GHNC was significantly correlated with the radiologists' score. In multivariate analysis, the extent of fibrosis as determined by GHNC was significantly correlated with FVC (p < 0.001). There was no significant difference between the results obtained using different CT scanners. Gaussian histogram normalized correlation was feasible, irrespective of the type of CT scanner used.

  1. Reproducibility and quantitativity of oblique-angle reconstruction in single photon emission computed tomography using Tl-201 myocardial phantom

    International Nuclear Information System (INIS)

    Bunko, Hisashi; Nanbu, Ichiro; Seki, Hiroyasu

    1984-01-01

    This study was carried out in order to evaluate reproducibility and quantitativity of oblique-angle reconstruction of myocardial phantom SPECT. Myocardial phantom with transmural and subendcardial defects, and off-axis phantom with wall thickness changing continuously from 0 to 23 mm were used. Sixty projection data in every 6 0 were aquired using dual-camera (ZLC) with high resolution collimators connected to Scintipac-2400 computer system. Oblique-angle reconstructed images were obtained by indicating the long axis of the phantom manually in the transaxial and vertical long axial tomograms. Reproducibility and quantitativity were evaluated by creating circumferential profile (CFP) of the finally reconstructed short axial images. Inter- and intra-operater reproducibility of relative counting ratio were less than 6.7% (C.V.) and 3.3% (C.V.), respectively. Both inter- and intraoperater reproducibility of absolute counts were better than that of counting ratio (less than 5.1% (C.V.) and 2.9% (C.V.), respectively). Variation of defect location in the reconstructed image and between the slices were less than 1 sampling interval of CFP (6 0 ) and 0.6 slice, respectively. Quantitativity of counts in the reconstructed images was poor in the transmulal defect, but was fair in the subendocardial defect. Counting ratio was greatly affected by wall thickness. Temporal quantitatibity or linearity of the counts in sequential SPECTs was good in non-defect area, especially when wall thickness was greater than 70% (16 mm) of maximum. In conclusion, three-dimensional oblique-angle reconstruction in Tl-201 myocardial SPECT could be applicable to relative and temporal quantitation of local myocardial activity other than defect area for the quantitative evaluation of Tl-201 myocardial wash-out. (J.P.N.)

  2. Effects of normalization on quantitative traits in association test

    Science.gov (United States)

    2009-01-01

    Background Quantitative trait loci analysis assumes that the trait is normally distributed. In reality, this is often not observed and one strategy is to transform the trait. However, it is not clear how much normality is required and which transformation works best in association studies. Results We performed simulations on four types of common quantitative traits to evaluate the effects of normalization using the logarithm, Box-Cox, and rank-based transformations. The impact of sample size and genetic effects on normalization is also investigated. Our results show that rank-based transformation gives generally the best and consistent performance in identifying the causal polymorphism and ranking it highly in association tests, with a slight increase in false positive rate. Conclusion For small sample size or genetic effects, the improvement in sensitivity for rank transformation outweighs the slight increase in false positive rate. However, for large sample size and genetic effects, normalization may not be necessary since the increase in sensitivity is relatively modest. PMID:20003414

  3. Effects of normalization on quantitative traits in association test

    Directory of Open Access Journals (Sweden)

    Yap Von Bing

    2009-12-01

    Full Text Available Abstract Background Quantitative trait loci analysis assumes that the trait is normally distributed. In reality, this is often not observed and one strategy is to transform the trait. However, it is not clear how much normality is required and which transformation works best in association studies. Results We performed simulations on four types of common quantitative traits to evaluate the effects of normalization using the logarithm, Box-Cox, and rank-based transformations. The impact of sample size and genetic effects on normalization is also investigated. Our results show that rank-based transformation gives generally the best and consistent performance in identifying the causal polymorphism and ranking it highly in association tests, with a slight increase in false positive rate. Conclusion For small sample size or genetic effects, the improvement in sensitivity for rank transformation outweighs the slight increase in false positive rate. However, for large sample size and genetic effects, normalization may not be necessary since the increase in sensitivity is relatively modest.

  4. Toward standardized quantitative image quality (IQ) assessment in computed tomography (CT): A comprehensive framework for automated and comparative IQ analysis based on ICRU Report 87.

    Science.gov (United States)

    Pahn, Gregor; Skornitzke, Stephan; Schlemmer, Hans-Peter; Kauczor, Hans-Ulrich; Stiller, Wolfram

    2016-01-01

    Based on the guidelines from "Report 87: Radiation Dose and Image-quality Assessment in Computed Tomography" of the International Commission on Radiation Units and Measurements (ICRU), a software framework for automated quantitative image quality analysis was developed and its usability for a variety of scientific questions demonstrated. The extendable framework currently implements the calculation of the recommended Fourier image quality (IQ) metrics modulation transfer function (MTF) and noise-power spectrum (NPS), and additional IQ quantities such as noise magnitude, CT number accuracy, uniformity across the field-of-view, contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) of simulated lesions for a commercially available cone-beam phantom. Sample image data were acquired with different scan and reconstruction settings on CT systems from different manufacturers. Spatial resolution is analyzed in terms of edge-spread function, line-spread-function, and MTF. 3D NPS is calculated according to ICRU Report 87, and condensed to 2D and radially averaged 1D representations. Noise magnitude, CT numbers, and uniformity of these quantities are assessed on large samples of ROIs. Low-contrast resolution (CNR, SNR) is quantitatively evaluated as a function of lesion contrast and diameter. Simultaneous automated processing of several image datasets allows for straightforward comparative assessment. The presented framework enables systematic, reproducible, automated and time-efficient quantitative IQ analysis. Consistent application of the ICRU guidelines facilitates standardization of quantitative assessment not only for routine quality assurance, but for a number of research questions, e.g. the comparison of different scanner models or acquisition protocols, and the evaluation of new technology or reconstruction methods. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  5. A multiresolution image based approach for correction of partial volume effects in emission tomography

    International Nuclear Information System (INIS)

    Boussion, N; Hatt, M; Lamare, F; Bizais, Y; Turzo, A; Rest, C Cheze-Le; Visvikis, D

    2006-01-01

    Partial volume effects (PVEs) are consequences of the limited spatial resolution in emission tomography. They lead to a loss of signal in tissues of size similar to the point spread function and induce activity spillover between regions. Although PVE can be corrected for by using algorithms that provide the correct radioactivity concentration in a series of regions of interest (ROIs), so far little attention has been given to the possibility of creating improved images as a result of PVE correction. Potential advantages of PVE-corrected images include the ability to accurately delineate functional volumes as well as improving tumour-to-background ratio, resulting in an associated improvement in the analysis of response to therapy studies and diagnostic examinations, respectively. The objective of our study was therefore to develop a methodology for PVE correction not only to enable the accurate recuperation of activity concentrations, but also to generate PVE-corrected images. In the multiresolution analysis that we define here, details of a high-resolution image H (MRI or CT) are extracted, transformed and integrated in a low-resolution image L (PET or SPECT). A discrete wavelet transform of both H and L images is performed by using the 'a trous' algorithm, which allows the spatial frequencies (details, edges, textures) to be obtained easily at a level of resolution common to H and L. A model is then inferred to build the lacking details of L from the high-frequency details in H. The process was successfully tested on synthetic and simulated data, proving the ability to obtain accurately corrected images. Quantitative PVE correction was found to be comparable with a method considered as a reference but limited to ROI analyses. Visual improvement and quantitative correction were also obtained in two examples of clinical images, the first using a combined PET/CT scanner with a lymphoma patient and the second using a FDG brain PET and corresponding T1-weighted MRI in

  6. Visualization of Radial Peripapillary Capillaries Using Optical Coherence Tomography Angiography: The Effect of Image Averaging.

    Directory of Open Access Journals (Sweden)

    Shelley Mo

    Full Text Available To assess the effect of image registration and averaging on the visualization and quantification of the radial peripapillary capillary (RPC network on optical coherence tomography angiography (OCTA.Twenty-two healthy controls were imaged with a commercial OCTA system (AngioVue, Optovue, Inc.. Ten 10x10° scans of the optic disc were obtained, and the most superficial layer (50-μm slab extending from the inner limiting membrane was extracted for analysis. Rigid registration was achieved using ImageJ, and averaging of each 2 to 10 frames was performed in five ~2x2° regions of interest (ROI located 1° from the optic disc margin. The ROI were automatically skeletonized. Signal-to-noise ratio (SNR, number of endpoints and mean capillary length from the skeleton, capillary density, and mean intercapillary distance (ICD were measured for the reference and each averaged ROI. Repeated measures analysis of variance was used to assess statistical significance. Three patients with primary open angle glaucoma were also imaged to compare RPC density to controls.Qualitatively, vessels appeared smoother and closer to histologic descriptions with increasing number of averaged frames. Quantitatively, number of endpoints decreased by 51%, and SNR, mean capillary length, capillary density, and ICD increased by 44%, 91%, 11%, and 4.5% from single frame to 10-frame averaged, respectively. The 10-frame averaged images from the glaucomatous eyes revealed decreased density correlating to visual field defects and retinal nerve fiber layer thinning.OCTA image registration and averaging is a viable and accessible method to enhance the visualization of RPCs, with significant improvements in image quality and RPC quantitative parameters. With this technique, we will be able to non-invasively and reliably study RPC involvement in diseases such as glaucoma.

  7. Quantitative assessment of rat corneal thickness and morphology during stem cell therapy by high-speed optical coherence tomography

    Science.gov (United States)

    Lal, Cerine; McGrath, James; Subhash, Hrebesh; Rani, Sweta; Ritter, Thomas; Leahy, Martin

    2016-03-01

    Optical Coherence Tomography (OCT) is a non-invasive 3 dimensional optical imaging modality that enables high resolution cross sectional imaging in biological tissues and materials. Its high axial and lateral resolution combined with high sensitivity, imaging depth and wide field of view makes it suitable for wide variety of high resolution medical imaging applications at clinically relevant speed. With the advent of swept source lasers, the imaging speed of OCT has increased considerably in recent years. OCT has been used in ophthalmology to study dynamic changes occurring in the cornea and iris, thereby providing physiological and pathological changes that occur within the anterior segment structures such as in glaucoma, during refractive surgery, lamellar keratoplasty and corneal diseases. In this study, we assess the changes in corneal thickness in the anterior segment of the eye during wound healing process in a rat corneal burn model following stem cell therapy using high speed swept source OCT.

  8. Quantitative, simultaneous, and collinear eye-tracked, high dynamic range optical coherence tomography at 850 and 1060 nm

    Science.gov (United States)

    Mooser, Matthias; Burri, Christian; Stoller, Markus; Luggen, David; Peyer, Michael; Arnold, Patrik; Meier, Christoph; Považay, Boris

    2017-07-01

    Ocular optical coherence tomography at the wavelengths ranges of 850 and 1060 nm have been integrated with a confocal scanning laser ophthalmoscope eye-tracker as a clinical commercial-class system. Collinear optics enables an exact overlap of the different channels to produce precisely overlapping depth-scans for evaluating the similarities and differences between the wavelengths to extract additional physiologic information. A reliable segmentation algorithm utilizing Graphcuts has been implemented and applied to automatically extract retinal and choroidal shape in cross-sections and volumes. The device has been tested in normals and pathologies including a cross-sectional and longitudinal study of myopia progress and control with a duplicate instrument in Asian children.

  9. Quantitative assessment of liquid Ga penetration into an aluminium alloy by high-resolution X-ray tomography

    International Nuclear Information System (INIS)

    Ohgaki, T.; Toda, H.; Sinclair, I.; Buffiere, J.-Y.; Ludwig, W.; Kobayashi, T.; Niinomi, M.; Akahori, T.

    2005-01-01

    We have evaluated the liquid Ga penetration into an aluminium alloy by high-resolution X-ray tomography. The 3D visualization of a crack together with its surrounding grain structure was performed with the help of the Ga penetration technique. It is found that the advance directions of the crack-tip were strongly influenced by the grain microstructure and the branching of the crack is affected by grain distribution. In this study, the liquid Ga not only acts as a contrast agent for grain boundaries, but also expands the volume of the Al alloy due to Ga diffusion and associated processes. The 3D strain between the grains has been determined by microstructural gauging technique, which uses micropores as marker points. The 3D expansion of the sample volume, the volume reduction of micropores and the brittle fracture were evidently observed

  10. Quantitative assessment of lipoprotein metabolism by positron emission tomography with an 18F-containing residualizing label

    International Nuclear Information System (INIS)

    Daugherty, A.; Sobel, B.; Kilbourn, M.R.; Dence, C.S.; Thorpe, S.R.

    1992-01-01

    Residualizing labels for proteins are designed to remain entrapped within cells following uptake and degradation of the carrier protein. In the present work we report the synthesis of a novel residualizing label, N-lactitol-S-([ 18 F]fluorophenacyl)-cysteamine ([ 18 F]LCSH), and its use for quantifying the accumulation of low density lipoprotein in tissues in vivo by positron emission tomography (PET). The retention of degradation products in tissues from lipoprotein or from other rapidly catabolized protein pharmaceuticals tagged with [ 18 F]LCSH reduces leakage of tracer into the plasma compartment. Thus, residualizing labels provide a valuable tool for enhancing signal-to-noise ratios, even during the relatively short interval of PET studies. (author)

  11. Analysis of photodynamic cream effect in dental caries using optical coherence tomography

    Science.gov (United States)

    Barbosa, P. S.; Freitas, A. Z.; de Sant´Anna, G. R.

    2015-06-01

    The aim of this study was to assess the effect in the enamel demineralization of low-intensity infrared laser (λ=810 nm, 100 mW/cm2, 90 sec, 4.47 J/cm2, 9 J) with or without photodynamic cream fluorinated or not fluorinated, using Optical Coherence Tomography (OCT). Background data: Lasers can be used as tools for the prevention of tooth enamel demineralization. All enamel specimens (n= 105) were analyzed using OCT at baseline, and randomly assigned into seven groups (n=15): C (+), laser application; C(-), no treatment; (F), acid fluoride gel; cream (IV); cream and neutral fluoride (IVF); cream and laser (IVL); and cream with neutral fluoride+ laser (IVFL). The specimens were submitted to all kind of treatments before demineralizing pH cycling challenge and were reanalyzed. ANOVA and Tukey's multiple comparative analysis (p <0.01) demonstrated a greater delta attenuation between baseline and post challenge for C + (0.034 +/- 0.011) compared to IVF (0.016 +/- 0.007) F (0.018 +/- 0.010) IVFL (0.019 +/- 0.008), and IVL (0.014 +/- 0.010). The cream laser group (IVL) also showed lower delta (0.014 +/- 0.010) compared to C - (0.025 +/- 0.008). The OCT technique demonstrated that cream associated with laser showed the lowest quantitative enamel mineral looses after cariogenic challenge.

  12. Nanoparticle-enhanced spectral photoacoustic tomography: effect of oxygen saturation and tissue heterogeneity

    Science.gov (United States)

    Vogt, William C.; Jia, Congxian; Wear, Keith A.; Garra, Brian S.; Pfefer, T. Joshua

    2016-03-01

    Molecular imaging for breast cancer detection, infectious disease diagnostics and preclinical animal research may be achievable through combined use of targeted exogenous agents - such as nanoparticles - and spectral Photoacoustic Tomography (PAT). However, tissue heterogeneity can alter fluence distributions and acoustic propagation, corrupting measured PAT absorption spectra and complicating in vivo nanoparticle detection and quantitation. Highly absorptive vascular structures represent a common confounding factor, and variations in vessel hemoglobin saturation (SO2) may alter spectral content of signals from adjacent/deeper regions. To evaluate the impact of this effect on PAT nanoparticle detectability, we constructed heterogeneous phantoms with well-characterized channel-inclusion geometries and biologically relevant optical and acoustic properties. Phantoms contained an array of tubes at several depths filled with hemoglobin solutions doped with varying concentrations of gold nanorods with an absorption peak at 780 nm. Both overlying and target network SO2 was tuned using sodium dithionite. Phantoms were imaged from 700 to 900 nm using a custom PAT system comprised of a tunable pulsed laser and a research-grade ultrasound system. Recovered nanoparticle spectra were analyzed and compared with results from both spectrophotometry and PAT data from waterimmersed tubes containing blood and nanoparticle solutions. Results suggested that nanoparticle selection for a given PAT application should take into account expected oxygenation states of both target blood vessel and background tissue oxygenation to achieve optimal performance.

  13. Effect of radiation dose and adaptive statistical iterative reconstruction on image quality of pulmonary computed tomography

    International Nuclear Information System (INIS)

    Sato, Jiro; Akahane, Masaaki; Inano, Sachiko; Terasaki, Mariko; Akai, Hiroyuki; Katsura, Masaki; Matsuda, Izuru; Kunimatsu, Akira; Ohtomo, Kuni

    2012-01-01

    The purpose of this study was to assess the effects of dose and adaptive statistical iterative reconstruction (ASIR) on image quality of pulmonary computed tomography (CT). Inflated and fixed porcine lungs were scanned with a 64-slice CT system at 10, 20, 40 and 400 mAs. Using automatic exposure control, 40 mAs was chosen as standard dose. Scan data were reconstructed with filtered back projection (FBP) and ASIR. Image pairs were obtained by factorial combination of images at a selected level. Using a 21-point scale, three experienced radiologists independently rated differences in quality between adjacently displayed paired images for image noise, image sharpness and conspicuity of tiny nodules. A subjective quality score (SQS) for each image was computed based on Anderson's functional measurement theory. The standard deviation was recorded as a quantitative noise measurement. At all doses examined, SQSs improved with ASIR for all evaluation items. No significant differences were noted between the SQSs for 40%-ASIR images obtained at 20 mAs and those for FBP images at 40 mAs. Compared to the FBP algorithm, ASIR for lung CT can enable an approximately 50% dose reduction from the standard dose while preserving visualization of small structures. (author)

  14. Disturbances in the cerebral perfusion of human immune deficiency virus-1 seropositive asymptomatic subjects: A quantitative tomography study of 18 cases

    International Nuclear Information System (INIS)

    Tran Dinh, Y.R.; Mamo, H.; Cervoni, J.; Caulin, C.; Saimot, A.C.

    1990-01-01

    Quantitative measurements of cerebral blood flow (CBF) by xenon-133 ( 133 Xe) tomography, together with magnetic resonance imaging (MRI), electroencephalography (EEG), psychometric tests, and laboratory analyses were performed on 18 human immunodeficiency virus 1 (HIV-1) seropositive asymptomatic subjects. Abnormalities of cerebral perfusion were observed in 16 cases (88%). These abnormalities were particularly frequent in the frontal regions (77% of cases). MRI demonstrated leucoencephalopathy in only two cases. EEG showed only induced diffuse abnormalities in two cases. Psychometric tests showed restricted moderate disturbances in 55% of patients. These disturbances mostly concerned those sectors involved in cognitive functions and memorization. These results indicate that quantitative measurements of CBF by 133 Xe-SPECT is capable of detecting abnormalities of cerebral perfusion at a very early stage (Phase II) of HIV-1 infection. These abnormalities are indications of disturbances resulting from unidentified metabolic or vascular lesions. This technique appears to be superior to MRI at this stage of the disease's development. It could provide objective information leading to earlier treatment, and prove useful in evaluating potential antiviral chemotherapy

  15. Quantitative thallium-201 single-photon emission computed tomography during maximal pharmacologic coronary vasodilation with adenosine for assessing coronary artery disease

    International Nuclear Information System (INIS)

    Nishimura, S.; Mahmarian, J.J.; Boyce, T.M.; Verani, M.S.

    1991-01-01

    The diagnostic value of maximal pharmacologic coronary vasodilation with intravenously administered adenosine in conjunction with thallium-201 single-photon emission computed tomography (SPECT) for detection of coronary artery disease was investigated in 101 consecutive patients who had concomitant coronary arteriography. Tomographic images were assessed visually and from computer-quantified polar maps of the thallium-201 distribution. Significant coronary artery disease, defined as greater than 50% luminal diameter stenosis, was present in 70 patients. The sensitivity for detecting patients with coronary artery disease using quantitative analysis was 87% in the total group, 82% in patients without myocardial infarction and 96% in those with prior myocardial infarction; the specificity was 90%. The sensitivity for diagnosing coronary artery disease in patients without infarction with single-, double-and triple-vessel disease was 76%, 86% and 90%, respectively. All individual stenoses were identified in 68% of patients with double-vessel disease and in 65% of those with triple-vessel disease. The extent of the perfusion defects, as quantified by polar maps, was directly related to the extent of coronary artery disease. In conclusion, quantitative thallium-201 SPECT during adenosine infusion has high sensitivity and specificity for diagnosing the presence of coronary artery disease, localizing the anatomic site of coronary stenosis and identifying the majority of affected vascular regions in patients with multivessel involvement

  16. A qualitative and quantitative analysis of radiation dose and image quality of computed tomography images using adaptive statistical iterative reconstruction.

    Science.gov (United States)

    Hussain, Fahad Ahmed; Mail, Noor; Shamy, Abdulrahman M; Suliman, Alghamdi; Saoudi, Abdelhamid

    2016-05-08

    Image quality is a key issue in radiology, particularly in a clinical setting where it is important to achieve accurate diagnoses while minimizing radiation dose. Some computed tomography (CT) manufacturers have introduced algorithms that claim significant dose reduction. In this study, we assessed CT image quality produced by two reconstruction algorithms provided with GE Healthcare's Discovery 690 Elite positron emission tomography (PET) CT scanner. Image quality was measured for images obtained at various doses with both conventional filtered back-projection (FBP) and adaptive statistical iterative reconstruction (ASIR) algorithms. A stan-dard CT dose index (CTDI) phantom and a pencil ionization chamber were used to measure the CT dose at 120 kVp and an exposure of 260 mAs. Image quality was assessed using two phantoms. CT images of both phantoms were acquired at tube voltage (kV) of 120 with exposures ranging from 25 mAs to 400 mAs. Images were reconstructed using FBP and ASIR ranging from 10% to 100%, then analyzed for noise, low-contrast detectability, contrast-to-noise ratio (CNR), and modulation transfer function (MTF). Noise was 4.6 HU in water phantom images acquired at 260 mAs/FBP 120 kV and 130 mAs/50% ASIR 120 kV. The large objects (fre-quency ASIR, compared to 260 mAs/FBP. The application of ASIR for small objects (frequency >7 lp/cm) showed poor visibility compared to FBP at 260 mAs and even worse for images acquired at less than 130 mAs. ASIR blending more than 50% at low dose tends to reduce contrast of small objects (frequency >7 lp/cm). We concluded that dose reduction and ASIR should be applied with close attention if the objects to be detected or diagnosed are small (frequency > 7 lp/cm). Further investigations are required to correlate the small objects (frequency > 7 lp/cm) to patient anatomy and clinical diagnosis.

  17. Quantitative Analysis of {sup 18}F-Fluorodeoxyglucose Positron Emission Tomography Identifies Novel Prognostic Imaging Biomarkers in Locally Advanced Pancreatic Cancer Patients Treated With Stereotactic Body Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Yi [Department of Radiation Oncology, Stanford University, Palo Alto, California (United States); Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo (Japan); Song, Jie; Pollom, Erqi; Alagappan, Muthuraman [Department of Radiation Oncology, Stanford University, Palo Alto, California (United States); Shirato, Hiroki [Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo (Japan); Chang, Daniel T.; Koong, Albert C. [Department of Radiation Oncology, Stanford University, Palo Alto, California (United States); Stanford Cancer Institute, Stanford, California (United States); Li, Ruijiang, E-mail: rli2@stanford.edu [Department of Radiation Oncology, Stanford University, Palo Alto, California (United States); Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo (Japan); Stanford Cancer Institute, Stanford, California (United States)

    2016-09-01

    Purpose: To identify prognostic biomarkers in pancreatic cancer using high-throughput quantitative image analysis. Methods and Materials: In this institutional review board–approved study, we retrospectively analyzed images and outcomes for 139 locally advanced pancreatic cancer patients treated with stereotactic body radiation therapy (SBRT). The overall population was split into a training cohort (n=90) and a validation cohort (n=49) according to the time of treatment. We extracted quantitative imaging characteristics from pre-SBRT {sup 18}F-fluorodeoxyglucose positron emission tomography, including statistical, morphologic, and texture features. A Cox proportional hazard regression model was built to predict overall survival (OS) in the training cohort using 162 robust image features. To avoid over-fitting, we applied the elastic net to obtain a sparse set of image features, whose linear combination constitutes a prognostic imaging signature. Univariate and multivariate Cox regression analyses were used to evaluate the association with OS, and concordance index (CI) was used to evaluate the survival prediction accuracy. Results: The prognostic imaging signature included 7 features characterizing different tumor phenotypes, including shape, intensity, and texture. On the validation cohort, univariate analysis showed that this prognostic signature was significantly associated with OS (P=.002, hazard ratio 2.74), which improved upon conventional imaging predictors including tumor volume, maximum standardized uptake value, and total legion glycolysis (P=.018-.028, hazard ratio 1.51-1.57). On multivariate analysis, the proposed signature was the only significant prognostic index (P=.037, hazard ratio 3.72) when adjusted for conventional imaging and clinical factors (P=.123-.870, hazard ratio 0.53-1.30). In terms of CI, the proposed signature scored 0.66 and was significantly better than competing prognostic indices (CI 0.48-0.64, Wilcoxon rank sum test P<1e-6

  18. Multi-institutional Quantitative Evaluation and Clinical Validation of Smart Probabilistic Image Contouring Engine (SPICE) Autosegmentation of Target Structures and Normal Tissues on Computer Tomography Images in the Head and Neck, Thorax, Liver, and Male Pelvis Areas

    NARCIS (Netherlands)

    Zhu, Mingyao; Bzdusek, Karl; Brink, Carsten; Eriksen, Jesper Grau; Hansen, Olfred; Jensen, Helle Anita; Gay, Hiram A.; Thorstad, Wade; Widder, Joachim; Brouwer, Charlotte L.; Steenbakkers, Roel J. H. M.; Vanhauten, Hubertus A. M.; Cao, Jeffrey Q.; McBrayne, Gail; Patel, Salil H.; Cannon, Donald M.; Hardcastle, Nicholas; Tome, Wolfgang A.; Guckenberg, Matthias; Parikh, Parag J.

    2013-01-01

    Purpose: Clinical validation and quantitative evaluation of computed tomography (CT) image autosegmentation using Smart Probabilistic Image Contouring Engine (SPICE). Methods and Materials: CT images of 125 treated patients (32 head and neck [HN], 40 thorax, 23 liver, and 30 prostate) in 7

  19. Quantitative computed tomography of pulmonary emphysema and ventricular function in chronic obstructive pulmonary disease patients with pulmonary hypertension

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yu San; Jaw, Fu Shan [Institute of Biomedical Engineering, College of Medicine and College of Engineering, National Taiwan University, Taipei (China); Chen, Jo Yu; Tai, Mei Hwa [Dept. of Medical Imaging, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei (China); Hsu, Hsao Hsun [Dept. of Surgery, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei (China)

    2014-12-15

    This study strived to evaluate the relationship between degree of pulmonary emphysema and cardiac ventricular function in chronic obstructive pulmonary disease (COPD) patients with pulmonary hypertension (PH) using electrocardiographic-gated multidetector computed tomography (CT). Lung transplantation candidates with the diagnosis of COPD and PH were chosen for the study population, and a total of 15 patients were included. The extent of emphysema is defined as the percentage of voxels below -910 Hounsfield units in the lung windows in whole lung CT without intravenous contrast. Heart function parameters were measured by electrocardiographic-gated CT angiography. Linear regression analysis was conducted to examine the associations between percent emphysema and heart function indicators. Significant correlations were found between percent emphysema and right ventricular (RV) measurements, including RV end-diastolic volume (R2 = 0.340, p = 0.023), RV stroke volume (R2 = 0.406, p = 0.011), and RV cardiac output (R2 = 0.382, p = 0.014); the correlations between percent emphysema and left ventricular function indicators were not observed. The study revealed that percent emphysema is correlated with RV dysfunction among COPD patients with PH. Based on our findings, percent emphysema can be considered for use as an indicator to predict the severity of right ventricular dysfunction among COPD patients.

  20. Quantitative computed tomography of pulmonary emphysema and ventricular function in chronic obstructive pulmonary disease patients with pulmonary hypertension.

    Science.gov (United States)

    Huang, Yu-Sen; Hsu, Hsao-Hsun; Chen, Jo-Yu; Tai, Mei-Hwa; Jaw, Fu-Shan; Chang, Yeun-Chung

    2014-01-01

    This study strived to evaluate the relationship between degree of pulmonary emphysema and cardiac ventricular function in chronic obstructive pulmonary disease (COPD) patients with pulmonary hypertension (PH) using electrocardiographic-gated multidetector computed tomography (CT). Lung transplantation candidates with the diagnosis of COPD and PH were chosen for the study population, and a total of 15 patients were included. The extent of emphysema is defined as the percentage of voxels below -910 Hounsfield units in the lung windows in whole lung CT without intravenous contrast. Heart function parameters were measured by electrocardiographic-gated CT angiography. Linear regression analysis was conducted to examine the associations between percent emphysema and heart function indicators. Significant correlations were found between percent emphysema and right ventricular (RV) measurements, including RV end-diastolic volume (R(2) = 0.340, p = 0.023), RV stroke volume (R(2) = 0.406, p = 0.011), and RV cardiac output (R(2) = 0.382, p = 0.014); the correlations between percent emphysema and left ventricular function indicators were not observed. The study revealed that percent emphysema is correlated with RV dysfunction among COPD patients with PH. Based on our findings, percent emphysema can be considered for use as an indicator to predict the severity of right ventricular dysfunction among COPD patients.

  1. Quantitative three-dimensional analysis of root canal curvature in maxillary first molars using micro-computed tomography.

    Science.gov (United States)

    Lee, Jong-Ki; Ha, Byung-Hyun; Choi, Jeong-Ho; Heo, Seok-Mo; Perinpanayagam, Hiran

    2006-10-01

    In endodontic therapy, access and instrumentation are strongly affected by root canal curvature. However, the few studies that have actually measured curvature are mostly from two-dimensional radiographs. The purpose of this study was to measure the three-dimensional (3D) canal curvature in maxillary first molars using micro-computed tomography (microCT) and mathematical modeling. Extracted maxillary first molars (46) were scanned by microCT (502 image slices/tooth, 1024 X 1024 pixels, voxel size of 19.5 x 19.5 x 39.0 microm) and their canals reconstructed by 3D modeling software. The intersection of major and minor axes in the canal space of each image slice were connected to create an imaginary central axis for each canal. The radius of curvature of the tangential circle was measured and inverted as a measure of curvature using custom-made mathematical modeling software. Root canal curvature was greatest in the apical third and least in the middle third for all canals. The greatest curvatures were in the mesiobuccal (MB) canal (0.76 +/- 0.48 mm(-1)) with abrupt curves, and the least curvatures were in the palatal (P) canal (0.38 +/- 0.34 mm(-1)) with a gradual curve. This study has measured the 3D curvature of root canals in maxillary first molars and reinforced the value of microCT with mathematical modeling.

  2. Quantitative analysis of acute myocardial infarction using single photon emission computed tomography using technetium-99m pyrophosphate

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, Yasushi; Kokubu, Tatsuo; Murase, Kenya; Hamamoto, Ken; Itoh, Taketoshi; Doiuchi, Junji; Ochi, Takaaki

    1986-09-01

    The usefulness of single photon emission computed tomography (SPECT) using technetium-99m pyrophosphate (/sup 99m/Tc-PPi) was evaluated in 15 patients with acute myocardial infarction. SPECT was performed with a rotating gamma camera after conventional planar images were made. Infarct size was measured from transaxial images of myocardial pyrophosphate uptakes. In each slice, the boundary was defined by subtracting 70 percent of the maximal counts and the number of voxels automatically counted. This subtraction rate was determined by phantom study and by compraing SPECT using /sup 99m/Tc-PPi with thallium-201-gated myocardial scintigraphy (/sup 201/Tl gated SPECT). The planar images showed diffuse uptakes in two of the 15 patients, and in these cases it was difficult to detect the infarct site. In contrast, SPECT images clearly imaged the infarct site consistent with the electrocardiographic findings, and they were definitely separated from the uptakes in the bones in all cases. Infarct size, ranging from 3.4 ml to 78.3 ml, correlated well with cumulative creatine kinase release (r = 0.84, p < 0.01, y = 772x + 13900). Correlation of infarct size with peak serum creatine kinase level was also significant (r = 0.66, p < 0.01, y = 10.6x + 693). In conclusion, SPECT with /sup 99m/Tc-PPi is a useful means of investigating the spatial distribution of pyrophosphate uptake and of evaluating the size of myocardial infarction.

  3. In vivo quantitative imaging of dopamine receptors in human brain using positron emission tomography and (XWBr)bromospiperone

    Energy Technology Data Exchange (ETDEWEB)

    Maziere, B; Loc' h, C; Barton, J -C; Sgouropoulos, P; Duquesnoy, N; Antona, R d' ; Cambon, H

    1985-08-27

    The brain regional distribution and kinetics of (XWBr)bromospiperone, a derivative of a neuroleptic (spiperone) labeled with the positron emitter bromine-76, were studied by time-of-flight tomography after i.v. injection in man. In a control subject the kinetic distribution study showed an accumulation of radioactivity which reached a maximum 3 h postinjection in the frontal cortex and cerebellum regions and 4-5 h postinjection in the basal ganglia. Thereafter the striatal activity remained essentially constant over a period of 25 h. In a group of 13 control subjects, the mean value for the striatum-to-cerebellum ratio, at 4.5 h postinjection, was 1.84 (S.D. 0.21). In two schizophrenics treated with high doses of haloperidol, this ratio was found to be only 1.22. These data indicate that radiolabeled bromospiperone is very suitable for human pharmacological or pathological investigations of the central dopaminergic system. (Auth.). 20 refs.; 3 figs.; 1 table.

  4. Quantitative analysis of acute myocardial infarction using single photon emission computed tomography using technetium-99m pyrophosphate

    International Nuclear Information System (INIS)

    Fujiwara, Yasushi; Kokubu, Tatsuo; Murase, Kenya; Hamamoto, Ken; Itoh, Taketoshi; Doiuchi, Junji; Ochi, Takaaki.

    1986-01-01

    The usefulness of single photon emission computed tomography (SPECT) using technetium-99m pyrophosphate ( 99m Tc-PPi) was evaluated in 15 patients with acute myocardial infarction. SPECT was performed with a rotating gamma camera after conventional planar images were made. Infarct size was measured from transaxial images of myocardial pyrophosphate uptakes. In each slice, the boundary was defined by subtracting 70 percent of the maximal counts and the number of voxels automatically counted. This subtraction rate was determined by phantom study and by compraing SPECT using 99m Tc-PPi with thallium-201-gated myocardial scintigraphy ( 201 Tl gated SPECT). The planar images showed diffuse uptakes in two of the 15 patients, and in these cases it was difficult to detect the infarct site. In contrast, SPECT images clearly imaged the infarct site consistent with the electrocardiographic findings, and they were definitely separated from the uptakes in the bones in all cases. Infarct size, ranging from 3.4 ml to 78.3 ml, correlated well with cumulative creatine kinase release (r = 0.84, p 99m Tc-PPi is a useful means of investigating the spatial distribution of pyrophosphate uptake and of evaluating the size of myocardial infarction. (author)

  5. Quantitative computed tomography of pulmonary emphysema and ventricular function in chronic obstructive pulmonary disease patients with pulmonary hypertension

    International Nuclear Information System (INIS)

    Huang, Yu San; Jaw, Fu Shan; Chen, Jo Yu; Tai, Mei Hwa; Hsu, Hsao Hsun

    2014-01-01

    This study strived to evaluate the relationship between degree of pulmonary emphysema and cardiac ventricular function in chronic obstructive pulmonary disease (COPD) patients with pulmonary hypertension (PH) using electrocardiographic-gated multidetector computed tomography (CT). Lung transplantation candidates with the diagnosis of COPD and PH were chosen for the study population, and a total of 15 patients were included. The extent of emphysema is defined as the percentage of voxels below -910 Hounsfield units in the lung windows in whole lung CT without intravenous contrast. Heart function parameters were measured by electrocardiographic-gated CT angiography. Linear regression analysis was conducted to examine the associations between percent emphysema and heart function indicators. Significant correlations were found between percent emphysema and right ventricular (RV) measurements, including RV end-diastolic volume (R2 = 0.340, p = 0.023), RV stroke volume (R2 = 0.406, p = 0.011), and RV cardiac output (R2 = 0.382, p = 0.014); the correlations between percent emphysema and left ventricular function indicators were not observed. The study revealed that percent emphysema is correlated with RV dysfunction among COPD patients with PH. Based on our findings, percent emphysema can be considered for use as an indicator to predict the severity of right ventricular dysfunction among COPD patients.

  6. Quantitative depth resolved microcirculation imaging with optical coherence tomography angiography (Part ΙΙ): Microvascular network imaging.

    Science.gov (United States)

    Gao, Wanrong

    2017-04-17

    In this work, we review the main phenomena that have been explored in OCT angiography to image the vessels of the microcirculation within living tissues with the emphasis on how the different processing algorithms were derived to circumvent specific limitations. Parameters are then discussed that can quantitatively describe the depth-resolved microvascular network for possible clinic diagnosis applications. Finally,future directions in continuing OCT development are discussed. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  7. A quantitative experiment on the fountain effect in superfluid helium

    Science.gov (United States)

    Amigó, M. L.; Herrera, T.; Neñer, L.; Peralta Gavensky, L.; Turco, F.; Luzuriaga, J.

    2017-09-01

    Superfluid helium, a state of matter existing at low temperatures, shows many remarkable properties. One example is the so called fountain effect, where a heater can produce a jet of helium. This converts heat into mechanical motion; a machine with no moving parts, but working only below 2 K. Allen and Jones first demonstrated the effect in 1938, but their work was basically qualitative. We now present data of a quantitative version of the experiment. We have measured the heat supplied, the temperature and the height of the jet produced. We also develop equations, based on the two-fluid model of superfluid helium, that give a satisfactory fit to the data. The experiment has been performed by advanced undergraduate students in our home institution, and illustrates in a vivid way some of the striking properties of the superfluid state.

  8. Quantitative radiomics: impact of stochastic effects on textural feature analysis implies the need for standards.

    Science.gov (United States)

    Nyflot, Matthew J; Yang, Fei; Byrd, Darrin; Bowen, Stephen R; Sandison, George A; Kinahan, Paul E

    2015-10-01

    Image heterogeneity metrics such as textural features are an active area of research for evaluating clinical outcomes with positron emission tomography (PET) imaging and other modalities. However, the effects of stochastic image acquisition noise on these metrics are poorly understood. We performed a simulation study by generating 50 statistically independent PET images of the NEMA IQ phantom with realistic noise and resolution properties. Heterogeneity metrics based on gray-level intensity histograms, co-occurrence matrices, neighborhood difference matrices, and zone size matrices were evaluated within regions of interest surrounding the lesions. The impact of stochastic variability was evaluated with percent difference from the mean of the 50 realizations, coefficient of variation and estimated sample size for clinical trials. Additionally, sensitivity studies were performed to simulate the effects of patient size and image reconstruction method on the quantitative performance of these metrics. Complex trends in variability were revealed as a function of textural feature, lesion size, patient size, and reconstruction parameters. In conclusion, the sensitivity of PET textural features to normal stochastic image variation and imaging parameters can be large and is feature-dependent. Standards are needed to ensure that prospective studies that incorporate textural features are properly designed to measure true effects that may impact clinical outcomes.

  9. Quantitative evaluation of the protective effect of respirators

    International Nuclear Information System (INIS)

    Murata, Mikio

    1983-01-01

    The present status and related problems of the quantitative evaluation method for respirator efficiency are generally reviewed. As the introduction, the special features of various types of respirators are summarized, and the basic concept of leakage and the protection factor are explained. As for the quantitative measurement of the protective efficiency, the features of various existing man-test methods such as NaCl aerosol man-test, DOP (dioctyl phthalate) man-test, and SF 6 gas man-test are reviewed and discussed. As the important problems associated with those man-tests, the following aspects are discussed. The measurement of the aerosol concentration within masks; the calculation method for the protection factor; the effect of beards. The examples of measuring the protection factor are also explained for the following respirator systems: half mask respirator with a high efficiency filter; full face mask respirator with a high efficiency filter; demand mode and pressure-demand mode respirators; and mound suit with suspenders. Finally, the outline of the manual of respiratory protection published by NRC in 1976 is briefly reviewed. (Aoki, K.)

  10. Quantitative in vivo micro-computed tomography for assessment of age-dependent changes in murine whole-body composition

    Directory of Open Access Journals (Sweden)

    Kim L. Beaucage

    2016-12-01

    Full Text Available Micro-computed tomography (micro-CT is used routinely to quantify skeletal tissue mass in small animal models. Our goal was to evaluate repeated in vivo micro-CT imaging for monitoring whole-body composition in studies of growth and aging in mice. Male mice from 2 to 52 weeks of age were anesthetized and imaged using an eXplore Locus Ultra and/or eXplore speCZT scanner. Images were reconstructed into 3D volumes, signal-intensity thresholds were used to classify each voxel as adipose, lean or skeletal tissue, and tissue masses were calculated from known density values. Images revealed specific changes in tissue distribution with growth and aging. Quantification showed biphasic increases in total CT-derived body mass, lean and skeletal tissue masses, consisting of rapid increases to 8 weeks of age, followed by slow linear increases to 52 weeks. In contrast, bone mineral density increased rapidly to a stable plateau at ~14 weeks of age. On the other hand, adipose tissue mass increased continuously with age. A micro-CT-derived total mass was calculated for each mouse and compared with gravimetrically measured mass, which differed on average by <3%. Parameters were highly reproducible for mice of the same age, but variability increased slightly with age. There was also good agreement in parameters for the same group of mice scanned on the eXplore Locus Ultra and eXplore speCZT systems. This study provides reference values for normative comparisons; as well, it demonstrates the usefulness of in vivo single-energy micro-CT scans to quantify whole-body composition in high-throughput studies of growth and aging in mice. Keywords: Adipose tissue, Bone mineral content, Bone mineral density, Growth, Lean tissue, Skeletal tissue

  11. Reducing image noise in computed tomography (CT) colonography: effect of an integrated circuit CT detector.

    Science.gov (United States)

    Liu, Yu; Leng, Shuai; Michalak, Gregory J; Vrieze, Thomas J; Duan, Xinhui; Qu, Mingliang; Shiung, Maria M; McCollough, Cynthia H; Fletcher, Joel G

    2014-01-01

    To investigate whether the integrated circuit (IC) detector results in reduced noise in computed tomography (CT) colonography (CTC). Three hundred sixty-six consecutive patients underwent clinically indicated CTC using the same CT scanner system, except for a difference in CT detectors (IC or conventional). Image noise, patient size, and scanner radiation output (volume CT dose index) were quantitatively compared between patient cohorts using each detector system, with separate comparisons for the abdomen and pelvis. For the abdomen and pelvis, despite significantly larger patient sizes in the IC detector cohort (both P 0.18). Based on the observed image noise reduction, radiation dose could alternatively be reduced by approximately 20% to result in similar levels of image noise. Computed tomography colonography images acquired using the IC detector had significantly lower noise than images acquired using the conventional detector. This noise reduction can permit further radiation dose reduction in CTC.

  12. Effect of intravenous contrast agent volume on colorectal cancer vascular parameters as measured by perfusion computed tomography

    International Nuclear Information System (INIS)

    Goh, V.; Bartram, C.; Halligan, S.

    2009-01-01

    Aim: To determine the effect of two different contrast agent volumes on quantitative and semi-quantitative vascular parameters as measured by perfusion computed tomography (CT) in colorectal cancer. Materials and methods: Following ethical approval and informed consent, eight prospectively recruited patients with proven colorectal adenocarcinoma underwent two separate perfusion CT studies on the same day after (a) 100 ml and (b) 50 ml of a 340 mg/ml iodinated contrast medium, respectively. Quantitative (blood volume, blood flow, permeability surface area product) and semi-quantitative (peak enhancement, time to peak enhancement) tumour vascular parameters were determined using commercial software based on distributed parameter analysis and compared using t-testing. Results: Tumour blood volume, blood flow, and permeability surface area product were not substantially different following the injection of 100 ml and 50 ml contrast medium: 6.12 versus 6.23 ml/100 g tissue; 73.4 versus 71.3 ml/min/100 g tissue; 15.6 versus 15.3 ml/min/100 g tissue for 100 and 50 ml, respectively; p > 0.05. Tumour peak enhancement and time to peak were significantly greater following the injection of 100 ml versus 50 ml contrast medium: 41.2 versus 28.5 HU; 16.1 versus 11.8 s for 100 ml and 50 ml, respectively; p = 0.002; p = 0.0003. Conclusion: Quantitative parameters do not appear to change substantially with a higher contrast agent volume suggesting a combined diagnostic staging-perfusion CT study following a single injection is feasible for colorectal cancer

  13. Role of quantitative myocardial positron emission tomography for risk stratification in patients with hypertrophic cardiomyopathy: a 2016 reappraisal

    Energy Technology Data Exchange (ETDEWEB)

    Castagnoli, Helga; Passeri, Alessandro; Berti, Valentina; Sciagra, Roberto [University of Florence, Department of Experimental and Clinical Biomedical Sciences - Nuclear Medicine Unit, Firenze (Italy); Ferrantini, Cecilia; Coppini, Raffaele; Baldini, Katia; Cecchi, Franco; Olivotto, Iacopo [Careggi University Hospital, Referral Center for Myocardial Diseases and Genetic Diagnostics Unit, Florence (Italy)

    2016-12-15

    Myocardial blood flow <1.1 mL/min/g following dipyridamole (Dip-MBF) assessed by positron emission tomography (PET) was identified in 2003 as an important outcome predictor in hypertrophic cardiomyopathy (HCM), based on scans performed in the 90s. However, such extreme Dip-MBF impairment is rarely observed in contemporary cohorts. We, therefore, reassessed the Dip-MBF threshold defining high-risk HCM patients. Dip-MBF was measured using {sup 13}N-ammonia in 100 HCM consecutive patients, prospectively enrolled and followed for 4.0 ± 2.2 years. Outcome was assessed based on tertiles of Dip-MBF. The study end-point was a combination of cardiovascular death, progression to severe functional limitation, cardioembolic stroke, life-threatening ventricular arrhythmias. Global Dip-MBF was 1.95 ± 0.85, ranging from 0.7 to 5.9 mL/min/g. Dip-MBF tertile cut-off values were: 0.73 to 1.53 mL/min/g (lowest), 1.54 to 2.13 mL/min/g (middle), and 2.14 to 5.89 mL/min/g (highest). During follow-up, lowest tertile Dip-MBF was associated with sevenfold independent risk of unfavorable outcome compared to the other two tertiles. Dip-MBF 1.35 mL/min/g was identified as the best threshold for outcome prediction. Regional perfusion analysis showed that all cardiac deaths (n = 4) occurred in patients in the lowest tertile of lateral wall Dip-MBF (≤1.72 mL/min/g); septal Dip-MBF was not predictive. Dip-MBF confirms its role as potent predictor of outcome in HCM. However, the threshold for prediction in a contemporary cohort is higher than that reported in earlier studies. Dip-MBF impairment in the lateral wall, possibly reflecting diffuse disease extending to non-hypertrophic regions, is a sensitive predictor of mortality in HCM. (orig.)

  14. Role of quantitative myocardial positron emission tomography for risk stratification in patients with hypertrophic cardiomyopathy: a 2016 reappraisal

    International Nuclear Information System (INIS)

    Castagnoli, Helga; Passeri, Alessandro; Berti, Valentina; Sciagra, Roberto; Ferrantini, Cecilia; Coppini, Raffaele; Baldini, Katia; Cecchi, Franco; Olivotto, Iacopo

    2016-01-01

    Myocardial blood flow <1.1 mL/min/g following dipyridamole (Dip-MBF) assessed by positron emission tomography (PET) was identified in 2003 as an important outcome predictor in hypertrophic cardiomyopathy (HCM), based on scans performed in the 90s. However, such extreme Dip-MBF impairment is rarely observed in contemporary cohorts. We, therefore, reassessed the Dip-MBF threshold defining high-risk HCM patients. Dip-MBF was measured using "1"3N-ammonia in 100 HCM consecutive patients, prospectively enrolled and followed for 4.0 ± 2.2 years. Outcome was assessed based on tertiles of Dip-MBF. The study end-point was a combination of cardiovascular death, progression to severe functional limitation, cardioembolic stroke, life-threatening ventricular arrhythmias. Global Dip-MBF was 1.95 ± 0.85, ranging from 0.7 to 5.9 mL/min/g. Dip-MBF tertile cut-off values were: 0.73 to 1.53 mL/min/g (lowest), 1.54 to 2.13 mL/min/g (middle), and 2.14 to 5.89 mL/min/g (highest). During follow-up, lowest tertile Dip-MBF was associated with sevenfold independent risk of unfavorable outcome compared to the other two tertiles. Dip-MBF 1.35 mL/min/g was identified as the best threshold for outcome prediction. Regional perfusion analysis showed that all cardiac deaths (n = 4) occurred in patients in the lowest tertile of lateral wall Dip-MBF (≤1.72 mL/min/g); septal Dip-MBF was not predictive. Dip-MBF confirms its role as potent predictor of outcome in HCM. However, the threshold for prediction in a contemporary cohort is higher than that reported in earlier studies. Dip-MBF impairment in the lateral wall, possibly reflecting diffuse disease extending to non-hypertrophic regions, is a sensitive predictor of mortality in HCM. (orig.)

  15. Positron emission tomography in oncology

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    This report describes the current and potential uses of positron emission tomography in clinical medicine and research related to oncology. Assessment will be possible of metabolism and physiology of tumors and their effects on adjacent tissues. Specific probes are likely to be developed for target sites on tumors, including monoclonal antibodies and specific growth factors that recognize tumors. To date, most oncological applications of positron emission tomography tracers have been qualitative; in the future, quantitative metabolic measurements should aid in the evaluation of tumor biology and response to treatment

  16. Quantitative assessment of optical properties in healthy cartilage and repair tissue by optical coherence tomography and histology (Conference Presentation)

    Science.gov (United States)

    Jansen, Sanne M. A.; Cernohorsky, Paul; de Bruin, Daniel M.; van der Pol, Edwin; Savci-Heijink, Cemile D.; Strackee, Simon D.; Faber, Dirk J.; van Leeuwen, Ton G.

    2016-02-01

    Quantification of the OCT signal is an important step toward clinical implementation of a diagnostic tool in cartilage imaging. Discrimination of structural cartilage differences in patients with osteoarthritis is critical, yet challenging. This study assesses the variation in the optical attenuation coefficient (μOCT) between healthy cartilage, repair tissue, bone and layers within repair tissue in a controlled setting. OCT and histology was used to assess goat talus articular surfaces in which central osteochondral defects were created. Exact matches of OCT and histology were selected for research. μOCT measurements were taken from healthy cartilage, repair tissue and bone. Measured μOCT in healthy cartilage was higher compared to both repair tissue and bone tissue. Two possible mechanisms for the difference in attenuation were investigated. We studied morphological parameters in terms of nucleus count, nucleus size and inter-nucleus distance. Collagen content in healthy cartilage and repair tissue was assessed using polarization microscopy. Quantitative analysis of the nuclei did not demonstrate a difference in nucleus size and count between healthy cartilage and repair tissue. In healthy cartilage, cells were spaced farther apart and had a lower variation in local nuclear density compared to repair tissue. Polarization microscopy suggested higher collagen content in healthy cartilage compared to repair tissue. μOCT measurements can distinguish between healthy cartilage, repair tissue and bone. Results suggest that cartilage OCT attenuation measurements could be of great impact in clinical diagnostics of osteoarthritis.

  17. Effect of quantization and interpolation of projections on the sensitivity of computerized tomography

    International Nuclear Information System (INIS)

    Vajnberg, Eh.I.; Fajngojz, M.L.

    1984-01-01

    The sources and forms of manifestation of errors in quantization and interpolation of projections in case of X-ray computerized tomography are considered and quantitative criteria of their evaluation are formulated. The dominating role of the interaction of two successive quantizations of projections - one-dimensional and two-dimensional ones is revealed. The necessity of joint optimization of the two-dimensional quantization range, expansion and form of interpolation function, quantized convolution nucleus is substantiated. The experimental results at aspect ratio of tomograms 256x256 and 480 projections are presented

  18. Computed Tomography of the Human Pineal Gland for Study of the Sleep-Wake Rhythm: Reproducibility of a Semi-Quantitative Approach

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, S.A.; Platzek, I.; Kunz, D.; Mahlberg, R.; Wolf, K.J.; Heidenreich, J.O. [Charite - Universitaetsmedizin Berlin, Campus Benjamin Franklin, Berlin (Germany). Dept. of Radiology and Nuclear Medicine

    2006-10-15

    Purpose: To propose a semi-quantitative computed tomography (CT) protocol for determining uncalcified pineal tissue (UCPT), and to evaluate its reproducibility in modification of studies showing that the degree of calcification is a potential marker of deficient melatonin production and may prove an instability marker of circadian rhythm. Material and Methods: Twenty-two pineal gland autopsy specimens were scanned in a skull phantom with different slice thickness twice and the uncalcified tissue visually assessed using a four-point scale. The maximum gland density was measured and its inverse graded on a non-linear four-point scale. The sum of both scores was multiplied by the gland volume to yield the UCPT. The within-subject variance of UCPT was determined and compared between scans of different slice thickness. Results: The UCPT of the first measurement, in arbitrary units, was 39{+-}52.5 for 1 mm slice thickness, 44{+-}51.1 for 2 mm, 45{+-}34.8 for 4 mm, and 84{+-}58.0 for 8 mm. Significant differences of within-subject variance of UCPT were found between 1 and 4 mm, 1 and 8 mm, and 2 and 8 mm slice thicknesses ( P <0.05). Conclusion: A superior reproducibility of the semi-quantitative CT determination of UCPT was found using 1 and 2 mm slice thicknesses. These data support the use of thin slices of 1 and 2 mm. The benefit in reproducibility from thin slices has to be carefully weighted against their considerably higher radiation exposure.

  19. Quantitative skeletal maturation estimation using cone-beam computed tomography-generated cervical vertebral images: a pilot study in 5- to 18-year-old Japanese children.

    Science.gov (United States)

    Byun, Bo-Ram; Kim, Yong-Il; Yamaguchi, Tetsutaro; Maki, Koutaro; Ko, Ching-Chang; Hwang, Dea-Seok; Park, Soo-Byung; Son, Woo-Sung

    2015-11-01

    The purpose of this study was to establish multivariable regression models for the estimation of skeletal maturation status in Japanese boys and girls using the cone-beam computed tomography (CBCT)-based cervical vertebral maturation (CVM) assessment method and hand-wrist radiography. The analyzed sample consisted of hand-wrist radiographs and CBCT images from 47 boys and 57 girls. To quantitatively evaluate the correlation between the skeletal maturation status and measurement ratios, a CBCT-based CVM assessment method was applied to the second, third, and fourth cervical vertebrae. Pearson's correlation coefficient analysis and multivariable regression analysis were used to determine the ratios for each of the cervical vertebrae (p maturation status according to the CBCT-based quantitative cervical vertebral maturation (QCVM) assessment was 5.90 + 99.11 × AH3/W3 - 14.88 × (OH2 + AH2)/W2 + 13.24 × D2; for the Japanese girls, it was 41.39 + 59.52 × AH3/W3 - 15.88 × (OH2 + PH2)/W2 + 10.93 × D2. The CBCT-generated CVM images proved very useful to the definition of the cervical vertebral body and the odontoid process. The newly developed CBCT-based QCVM assessment method showed a high correlation between the derived ratios from the second cervical vertebral body and odontoid process. There are high correlations between the skeletal maturation status and the ratios of the second cervical vertebra based on the remnant of dentocentral synchondrosis.

  20. Physical characterization of a time-of-flight positron emission tomography system for whole-body quantitative studies

    International Nuclear Information System (INIS)

    Soussaline, F.; Campagnolo, R.; Verrey, B.; Bendriem, B.; Bouvier, A.; Lecomte, J.L.; Comar, D.

    1984-01-01

    The design of a first PET system using the time of flight (TOF) information, is aimed at whole-body, quantitative, dynamic, 3D studies. It comprises 3 rings of 96 CsF probes and a ring of 96 BaF/sub 2/ probes. The physical performance was measured: spatial transverse and longitudinal resolution for a reconstructed source, sensitivity, time resolution (480 psec +- 28 psec for CsF and 380 psec +-28 psec for BaF/sub 2/), interplane (< 5% for the means difference for a uniform ring source) and intraplane uniformity (< 4% RMS uncertainty). Calibration in absolute concentration was performed with a precision of 2%. Special attention was directed to the specific advantages of the use of fast crystal -PM tubes for TOF measurements: very fast count rate studies, elimination of random events, and improvement of the S/N ratio. Counts rates up to a million counts per sec for each detector are feasible, without loss due to pile up. Actually, the maximum count rate is 450000 events/sec due to the transfert time to magnetic disc in list mode (30 μCi/cc). At these rates, the random fraction is 30% of the true coincidences rate, while it is less than 3% for concentration of 1 μCi/cc. The sensitivity gain was measured as a function of the object size: 2 for the head of 4.8 the wholebody. Other advantages of TOF as Compton events reduction and the accuracy of attenuation correction coefficients are evaluated for thoracic studies

  1. Effectiveness of Adaptive Statistical Iterative Reconstruction for 64-Slice Dual-Energy Computed Tomography Pulmonary Angiography in Patients With a Reduced Iodine Load: Comparison With Standard Computed Tomography Pulmonary Angiography.

    Science.gov (United States)

    Lee, Ji Won; Lee, Geewon; Lee, Nam Kyung; Moon, Jin Il; Ju, Yun Hye; Suh, Young Ju; Jeong, Yeon Joo

    2016-01-01

    The aim of the study was to assess the effectiveness of the adaptive statistical iterative reconstruction (ASIR) for dual-energy computed tomography pulmonary angiography (DE-CTPA) with a reduced iodine load. One hundred forty patients referred for chest CT were randomly divided into a DE-CTPA group with a reduced iodine load or a standard CTPA group. Quantitative and qualitative image qualities of virtual monochromatic spectral (VMS) images with filtered back projection (VMS-FBP) and those with 50% ASIR (VMS-ASIR) in the DE-CTPA group were compared. Image qualities of VMS-ASIR images in the DE-CTPA group and ASIR images in the standard CTPA group were also compared. All quantitative and qualitative indices, except attenuation value of pulmonary artery in the VMS-ASIR subgroup, were superior to those in the VMS-FBP subgroup (all P ASIR images were superior to those of ASIR images in the standard CTPA group (P ASIR images of the DE-CTPA group than in ASIR images of the standard CTPA group (P = 0.001). The ASIR technique tends to improve the image quality of VMS imaging. Dual-energy computed tomography pulmonary angiography with ASIR can reduce contrast medium volume and produce images of comparable quality with those of standard CTPA.

  2. Solitary pulmonary nodules: Impact of quantitative contrast-enhanced CT on the cost-effectiveness of FDG-PET

    International Nuclear Information System (INIS)

    Comber, L.A.; Keith, C.J.; Griffiths, M.; Miles, K.A.

    2003-01-01

    AIM: To determine the impact of quantitative contrast-enhanced computed tomography (QECT) on the cost-effectiveness of diagnostic strategies for the assessment of solitary pulmonary nodules (SPNs). MATERIALS AND METHODS: Four diagnostic strategies were evaluated using decision tree analysis: conventional CT alone; conventional CT followed by QECT; conventional CT followed positron emission tomography (PET); and conventional CT followed by QECT and PET (QECT+PET). The average cost per patient, accuracy of management and incremental cost:accuracy ratio (ICAR) were determined for each strategy. Although baseline assumptions reflected the Australian setting, sensitivity analysis was used to extrapolate the results to the UK. RESULTS: At the baseline prevalence of malignancy (54%) and cost of PET relative to surgery (16%), the QECT strategy incurs the least cost ($5560/patient) but the QECT+PET strategy is the most cost-effective (ICAR $12059/patient). At reported levels of disease prevalence (68.5%) and cost of PET relative to surgery (29.9%) in the UK, the QECT strategy is the most cost-effective. CONCLUSION: QECT offers a cost-effective approach to evaluation of SPNs. Whether QECT is used alone or in combination with PET will depend upon local availability and regional values for prior probability of malignancy within SPNs and the cost of PET relative to surgery

  3. Quantitative assessment of selective in-plane shielding of tissues in computed tomography through evaluation of absorbed dose and image quality

    International Nuclear Information System (INIS)

    Geleijns, J.; Veldkamp, W.J.H.; Salvado Artells, M.; Lopez Tortosa, M.; Calzado Cantera, A.

    2006-01-01

    This study aimed at assessment of efficacy of selective in-plane shielding in adults by quantitative evaluation of the achieved dose reduction and image quality. Commercially available accessories for in-plane shielding of the eye lens, thyroid and breast, and an anthropomorphic phantom were used for the evaluation of absorbed dose and image quality. Organ dose and total energy imparted were assessed by means of a Monte Carlo technique taking into account tube voltage, tube current, and scanner type. Image quality was quantified as noise in soft tissue. Application of the lens shield reduced dose to the lens by 27% and to the brain by 1%. The thyroid shield reduced thyroid dose by 26%; the breast shield reduced dose to the breasts by 30% and to the lungs by 15%. Total energy imparted (unshielded/shielded) was 88/86 mJ for computed tomography (CT) brain, 64/60 mJ for CT cervical spine, and 289/260 mJ for CT chest scanning. An increase in image noise could be observed in the ranges were bismuth shielding was applied. The observed reduction of organ dose and total energy imparted could be achieved more efficiently by a reduction of tube current. The application of in-plane selective shielding is therefore discouraged. (orig.)

  4. Quantitative Analysis of Lens Nuclear Density Using Optical Coherence Tomography (OCT with a Liquid Optics Interface: Correlation between OCT Images and LOCS III Grading

    Directory of Open Access Journals (Sweden)

    You Na Kim

    2016-01-01

    Full Text Available Purpose. To quantify whole lens and nuclear lens densities using anterior-segment optical coherence tomography (OCT with a liquid optics interface and evaluate their correlation with Lens Opacities Classification System III (LOCS III lens grading and corrected distance visual acuity (BCVA. Methods. OCT images of the whole lens and lens nucleus of eyes with age-related nuclear cataract were analyzed using ImageJ software. The lens grade and nuclear density were represented in pixel intensity units (PIU and correlations between PIU, BCVA, and LOCS III were assessed. Results. Forty-seven eyes were analyzed. The mean whole lens and lens nuclear densities were 26.99 ± 5.23 and 19.43 ± 6.15 PIU, respectively. A positive linear correlation was observed between lens opacities (R2 = 0.187, p<0.01 and nuclear density (R2 = 0.316, p<0.01 obtained from OCT images and LOCS III. Preoperative BCVA and LOCS III were also positively correlated (R2 = 0.454, p<0.01. Conclusions. Whole lens and lens nuclear densities obtained from OCT correlated with LOCS III. Nuclear density showed a higher positive correlation with LOCS III than whole lens density. OCT with a liquid optics interface is a potential quantitative method for lens grading and can aid in monitoring and managing age-related cataracts.

  5. Quantitative assessment of lung volumes using multi-detector row computed tomography (MDCT) in patients with chronic obstructive pulmonary disease (COPD)

    International Nuclear Information System (INIS)

    Lee, Sang Min; Hur, Jin; Kim, Tae Hoon; Kim, Sang Jin; Kim, Hyung Jung

    2008-01-01

    To evaluate the clinical value of the multi-detector row computed tomography (MDCT) in the quantitative assessment of lung volumes and to assess the relationship between the MDCT results and disease severity as determined by a pulmonary function test (PFT) in Chronic Obstructive Pulmonary Disease (COPD) patients. We performed a PFT and MDCT on 39 COPD patients. Using the GOLD classifications, we divided the patients into three groups according to disease severity; stage I (mild, n = 10), stage II (moderate, n = 15), and stage III (severe, n = 14). Using the pulmo-CT software program, we measured the proportion of lung volumes with attenuation values below -910 and -950 HU. The mean FEV1 (% of predicted) and FEV1/FVC was 82.2 ± 2% and 66.2 ± 3% in stage I, 53.5 ± 11% and 52 ± 6% in stage II, and 32.3 ± 7% and 44.2% ± 13% in stage III, respectively. Differences in lung volume percentage at each of the thresholds (-910 and -950 HU) among the 3 stages were statistically significant (ρ < 0.01, ρ < 0.01) and correlated well with the FEV1 and FEV1/FVC (r = -0.803, r -0.766, r = -0.817, and r = -0.795, respectively). The volumetric measurement obtained by MDCT provides an accurate means of quantifying pulmonary emphysema

  6. Quantitative analysis of TALE-DNA interactions suggests polarity effects.

    Science.gov (United States)

    Meckler, Joshua F; Bhakta, Mital S; Kim, Moon-Soo; Ovadia, Robert; Habrian, Chris H; Zykovich, Artem; Yu, Abigail; Lockwood, Sarah H; Morbitzer, Robert; Elsäesser, Janett; Lahaye, Thomas; Segal, David J; Baldwin, Enoch P

    2013-04-01

    Transcription activator-like effectors (TALEs) have revolutionized the field of genome engineering. We present here a systematic assessment of TALE DNA recognition, using quantitative electrophoretic mobility shift assays and reporter gene activation assays. Within TALE proteins, tandem 34-amino acid repeats recognize one base pair each and direct sequence-specific DNA binding through repeat variable di-residues (RVDs). We found that RVD choice can affect affinity by four orders of magnitude, with the relative RVD contribution in the order NG > HD ≈ NN > NI > NK. The NN repeat preferred the base G over A, whereas the NK repeat bound G with 10(3)-fold lower affinity. We compared AvrBs3, a naturally occurring TALE that recognizes its target using some atypical RVD-base combinations, with a designed TALE that precisely matches 'standard' RVDs with the target bases. This comparison revealed unexpected differences in sensitivity to substitutions of the invariant 5'-T. Another surprising observation was that base mismatches at the 5' end of the target site had more disruptive effects on affinity than those at the 3' end, particularly in designed TALEs. These results provide evidence that TALE-DNA recognition exhibits a hitherto un-described polarity effect, in which the N-terminal repeats contribute more to affinity than C-terminal ones.

  7. An Effective Measured Data Preprocessing Method in Electrical Impedance Tomography

    Directory of Open Access Journals (Sweden)

    Chenglong Yu

    2014-01-01

    Full Text Available As an advanced process detection technology, electrical impedance tomography (EIT has widely been paid attention to and studied in the industrial fields. But the EIT techniques are greatly limited to the low spatial resolutions. This problem may result from the incorrect preprocessing of measuring data and lack of general criterion to evaluate different preprocessing processes. In this paper, an EIT data preprocessing method is proposed by all rooting measured data and evaluated by two constructed indexes based on all rooted EIT measured data. By finding the optimums of the two indexes, the proposed method can be applied to improve the EIT imaging spatial resolutions. In terms of a theoretical model, the optimal rooting times of the two indexes range in [0.23, 0.33] and in [0.22, 0.35], respectively. Moreover, these factors that affect the correctness of the proposed method are generally analyzed. The measuring data preprocessing is necessary and helpful for any imaging process. Thus, the proposed method can be generally and widely used in any imaging process. Experimental results validate the two proposed indexes.

  8. Quantitative assessment of the effectiveness of a rockfall warning system

    Science.gov (United States)

    Bründl, Michael; Sättele, Martina; Krautblatter, Michael; Straub, Daniel

    2016-04-01

    Rockslides and rockfalls can pose high risk to human settlements and traffic infrastructure. In addition to structural mitigation measures like rockfall nets, warning systems are increasingly installed to reduce rockfall risks. Whereas for structural mitigation measures with reducing effects on the spatial extent a structured evaluation method is existing, no or only few approaches to assess the effectiveness for warning systems are known. Especially for higher magnitude rockfalls structural mitigation measures are not effective, and reliable early warning systems will be essential in future. In response to that, we developed a classification and a framework to assess the reliability and effectiveness of early warning systems (Sättele et al, 2015a; 2016). Here, we demonstrate an application for the rockfall warning system installed in Preonzo prior to a major rockfall in May 2012 (Sättele et al., 2015b). We show that it is necessary to design such a warning system as fail-safe construction, which has to incorporate components with low failure probabilities, high redundancy, low warning thresholds, and additional control systems. With a hypothetical probabilistic analysis, we investigate the effect of the risk attitude of decision makers and of the number of sensors on the probability of detecting an event and on initiating a timely evacuation, as well as on related intervention cost. We conclude that it is possible to quantitatively assess the effectiveness of warning systems, which helps to optimize mitigation strategies against rockfall events. References Sättele, M., Bründl, M., and Straub, D.: Reliability and effectiveness of warning systems for natural hazards: concept and application to debris flow warning, Rel. Eng. Syst. Safety, 142, 192-202, 2015a. Sättele, M., Krautblatter, M., Bründl, M., and Straub, D.: Forecasting rock slope failure: How reliable and effective are warning systems?, Landslides, 605, 1-14, 2015b. Sättele, M., Bründl, M., and

  9. Quantitative computed tomography bone mineral density measurements in irradiated and non-irradiated minipig alveolar bone: an experimental study.

    NARCIS (Netherlands)

    Verdonck, H.W.; Meijer, G.J.; Nieman, F.H.; Stoll, C.; Riediger, D.; Baat, C. de

    2008-01-01

    OBJECTIVE: The objective of this study was to analyse the effect of irradiation on bone mineral density (BMD). MATERIALS AND METHODS: All maxillary and mandibular pre-molars and molars of six minipigs were extracted. After a 3-month healing period, the maxilla and mandibles of three minipigs

  10. Quantitative parameters to compare image quality of non-invasive coronary angiography with 16-slice, 64-slice and dual-source computed tomography

    International Nuclear Information System (INIS)

    Burgstahler, Christof; Reimann, Anja; Brodoefel, Harald; Tsiflikas, Ilias; Thomas, Christoph; Heuschmid, Martin; Daferner, Ulrike; Drosch, Tanja; Schroeder, Stephen; Herberts, Tina

    2009-01-01

    Multi-slice computed tomography (MSCT) is a non-invasive modality to visualize coronary arteries with an overall good image quality. Improved spatial and temporal resolution of 64-slice and dual-source computed tomography (DSCT) scanners are supposed to have a positive impact on diagnostic accuracy and image quality. However, quantitative parameters to compare image quality of 16-slice, 64-slice MSCT and DSCT are missing. A total of 256 CT examinations were evaluated (Siemens, Sensation 16: n=90; Siemens Sensation 64: n=91; Siemens Definition: n=75). Mean Hounsfield units (HU) were measured in the cavum of the left ventricle (LV), the ascending aorta (Ao), the left ventricular myocardium (My) and the proximal part of the left main (LM), the left anterior descending artery (LAD), the right coronary artery (RCA) and the circumflex artery (CX). Moreover, the ratio of intraluminal attenuation (HU) to myocardial attenuation was assessed for all coronary arteries. Clinical data [body mass index (BMI), gender, heart rate] were accessible for all patients. Mean attenuation (CA) of the coronary arteries was significantly higher for DSCT in comparison to 64- and 16-slice MSCT within the RCA [347±13 vs. 254±14 (64-MSCT) vs. 233±11 (16-MSCT) HU], LM (362±11/275 ± 12/262±9), LAD (332±17/248±19/219±14) and LCX (310±12/210±13/221±10, all p<0.05), whereas there was no significant difference between DSCT and 64-MSCT for the LV, the Ao and My. Heart rate had a significant impact on CA ratio in 16-slice and 64-slice CT only (p<0.05). BMI had no impact on the CA ratio in DSCT only (p<0.001). Improved spatial and temporal resolution of dual-source CT is associated with better opacification of the coronary arteries and a better contrast with the myocardium, which is independent of heart rate. In comparison to MSCT, opacification of the coronary arteries at DSCT is not affected by BMI. The main advantage of DSCT lies with the heart rate independency, which might have a

  11. Effects of feed forms, levels of quantitative feed restriction on ...

    African Journals Online (AJOL)

    Nigerian Journal of Animal Production ... Data were collected on growth performance, carcass characteristics, and cost benefits were calculated. Data were subjected to ... Keywords: Broilers, carcass, performance, quantitative feed restriction ...

  12. Quantitatively Measured Anatomic Location and Volume of Optic Disc Drusen: An Enhanced Depth Imaging Optical Coherence Tomography Study

    DEFF Research Database (Denmark)

    Malmqvist, Lasse; Lindberg, Anne-Sofie Wessel; Dahl, Vedrana Andersen

    2017-01-01

    function using automated perimetric mean deviation (MD) and multifocal visual evoked potentials. Increased age (P = 0.015); larger ODD volume (P = 0.002); and more superficial anatomic ODD location (P = 0.007) were found in patients with ODD visible by ophthalmoscopy compared to patients with buried ODD.......025) and had a higher effect on MD when compared to retinal nerve fiber layer thickness. Large ODD volume is associated with optic nerve dysfunction. The worse visual field defects associated with visible ODD should only be ascribed to larger ODD volume and not to a more superficial anatomic ODD location....

  13. Positron emission tomography

    CERN Document Server

    Paans, A M J

    2006-01-01

    Positron Emission Tomography (PET) is a method for measuring biochemical and physiological processes in vivo in a quantitative way by using radiopharmaceuticals labelled with positron emitting radionuclides such as 11C, 13N, 15O and 18F and by measuring the annihilation radiation using a coincidence technique. This includes also the measurement of the pharmacokinetics of labelled drugs and the measurement of the effects of drugs on metabolism. Also deviations of normal metabolism can be measured and insight into biological processes responsible for diseases can be obtained. At present the combined PET/CT scanner is the most frequently used scanner for whole-body scanning in the field of oncology.

  14. Emission computed tomography

    International Nuclear Information System (INIS)

    Budinger, T.F.; Gullberg, G.T.; Huesman, R.H.

    1979-01-01

    This chapter is devoted to the methods of computer assisted tomography for determination of the three-dimensional distribution of gamma-emitting radionuclides in the human body. The major applications of emission computed tomography are in biological research and medical diagnostic procedures. The objectives of these procedures are to make quantitative measurements of in vivo biochemical and hemodynamic functions

  15. Bone mineral density in renal osteodystrophy: Comparison of dual energy X-ray absorptiometry and quantitative computed tomography. Vergleichende Untersuchungen mit der quantitativen Computertomographie und der Dual-Energy-X-Ray-Absorptiometrie zur Knochendichte bei renaler Osteopathie

    Energy Technology Data Exchange (ETDEWEB)

    Funke, M.; Maeurer, J.; Grabbe, E. (Abt. Roentgendiagnostik, Klinikum, Goettingen Univ. (Germany)); Scheler, F. (Abt. Nephrologie und Rheumatologie, Klinikum, Goettingen Univ. (Germany))

    1992-08-01

    Measurements of bone density were carried out in 25 patients on dialysis for terminal renal insufficiency, using quantitative computed tomography (QCT) and dual energy X-ray absorptiometry (DXA). Unlike in subjects with normal kidneys, there was no significant correlation between these methods in this series. Ten patients showed an increase in bone density of the vertebral spongiosa on QCT measurements, which was interpreted as due to osteosclerotic bone changes in renal osteopathy. QCT showed advantages over DXA in demonstrating these changes. (orig.).

  16. Positron emission tomography. Positronemisionstomografi

    Energy Technology Data Exchange (ETDEWEB)

    Bolwig, T G; Haunsoe, S; Dahlgaard Hove, J; Hesse, B; Hoejgard, L; Jensen, M; Paulson, O B; Hastrup Svendsen, J; Soelvsten Soerensen, S

    1994-10-01

    Positron emission tomography (PET) is a method for quantitative imaging of regional physiological and biochemical parameters. Positron emitting radioactive isotopes can be produced by a cyclotron, eg. the biologically important carbon ([sup 11]C), oxygen ([sup 15]O), and nitrogen ([sup 13]N) elements. With the tomographic principles of the PET scanner the quantitative distribution of the administered isotopes can be determined and images can be provided as well as dynamic information on blood flow, metabolism and receptor function. In neurology PET has been used for investigations on numerous physiological processes in the brain: circulation, metabolism and receptor studies. In Parkinson's disease PET studies have been able to localize the pathology specifically, and in early stroke PET technique can outline focal areas with living but non-functioning cells, and this could make it possible to intervene in this early state. With positron emission tomography a quantitative evaluation of myocardial blood flow, glucose and fatty acid metabolism can be made as well as combined assessments of blood flow and metabolism. Combined studies of blood flow and metabolism can determine whether myocardial segments with abnormal motility consist of necrotic or viable tissue, thereby delineating effects of revascularisation. In the future it will probably be possible to characterize the myocardial receptor status in different cardiac diseases. The PET technique is used in oncology for clinical as well as more basic research on tumor perfusion and metabolism. Further, tumor uptake of positron labelled cytotoxic drugs might predict the clinical benefit of treatment. (au) (19 refs.).

  17. Positron emission tomography

    International Nuclear Information System (INIS)

    Bolwig, T.G.; Haunsoe, S.; Dahlgaard Hove, J.; Hesse, B.; Hoejgard, L.; Jensen, M.; Paulson, O.B.; Hastrup Svendsen, J.; Soelvsten Soerensen, S.

    1994-01-01

    Positron emission tomography (PET) is a method for quantitative imaging of regional physiological and biochemical parameters. Positron emitting radioactive isotopes can be produced by a cyclotron, eg. the biologically important carbon ( 11 C), oxygen ( 15 O), and nitrogen ( 13 N) elements. With the tomographic principles of the PET scanner the quantitative distribution of the administered isotopes can be determined and images can be provided as well as dynamic information on blood flow, metabolism and receptor function. In neurology PET has been used for investigations on numerous physiological processes in the brain: circulation, metabolism and receptor studies. In Parkinson's disease PET studies have been able to localize the pathology specifically, and in early stroke PET technique can outline focal areas with living but non-functioning cells, and this could make it possible to intervene in this early state. With positron emission tomography a quantitative evaluation of myocardial blood flow, glucose and fatty acid metabolism can be made as well as combined assessments of blood flow and metabolism. Combined studies of blood flow and metabolism can determine whether myocardial segments with abnormal motility consist of necrotic or viable tissue, thereby delineating effects of revascularisation. In the future it will probably be possible to characterize the myocardial receptor status in different cardiac diseases. The PET technique is used in oncology for clinical as well as more basic research on tumor perfusion and metabolism. Further, tumor uptake of positron labelled cytotoxic drugs might predict the clinical benefit of treatment. (au) (19 refs.)

  18. Aerosolized intranasal midazolam for safe and effective sedation for quality computed tomography imaging in infants and children.

    Science.gov (United States)

    Mekitarian Filho, Eduardo; de Carvalho, Werther Brunow; Gilio, Alfredo Elias; Robinson, Fay; Mason, Keira P

    2013-10-01

    This pilot study introduces the aerosolized route for midazolam as an option for infant and pediatric sedation for computed tomography imaging. This technique produced predictable and effective sedation for quality computed tomography imaging studies with minimal artifact and no significant adverse events. Copyright © 2013 Mosby, Inc. All rights reserved.

  19. Quantitative analysis of the fission product distribution in a damaged fuel assembly using gamma-spectrometry and computed tomography for the Phébus FPT3 test

    International Nuclear Information System (INIS)

    Biard, B.

    2013-01-01

    Highlights: • The FP quantitative distribution in the fuel bundle is measured by gamma-spectrometry. • The FP location is obtained with emission tomograms and other experiment results. • X-ray tomograms provide the material and density mapping of the degraded bundle. • The self-attenuation may then be computed for each isotope at its key line energy. • Results are consistent with other FPT3 measurements, with acceptable uncertainties. -- Abstract: The international Phébus FP programme, initiated in 1988 by the French “Institut de Radioprotection et de Sûreté Nucléaire” (IRSN), in cooperation with the European Commission (EC) and with financial support from USNRC, Canada, PSI/HSK (Switzerland), Japan and Korea, was aimed at studying severe accident phenomena: the fuel degradation, the release of fission products (FPs) and their transport through the reactor coolant system to the containment building. The FPT3 test, conducted in 2004, was the last of the five light water reactor core meltdown accident tests performed on irradiated fuel rods. After the experiment, the test device was recovered and analysed through a full set of non-destructive examinations performed over the fuel bundle zone, including gamma-scanning, gamma emission tomography, X-ray radiography and X-ray transmission tomography. The gamma-scanning was specifically devoted to the location, identification and amount quantification of the FPs remaining in the bundle. Since the fuel bundle became highly degraded during the experiment, the geometry was different at each level examined, and did not correspond to the well-known initial state. The self-attenuation of the test device and consequently the efficiency correction could then not be estimated by classical means that need to know the geometry of the object. Using the results of the other non-destructive examinations, specific computational tools and methods have therefore been developed to compute the self-attenuation of the bundle

  20. Quantitative analysis of the fission product distribution in a damaged fuel assembly using gamma-spectrometry and computed tomography for the Phébus FPT3 test

    Energy Technology Data Exchange (ETDEWEB)

    Biard, B., E-mail: bruno.biard@irsn.fr

    2013-09-15

    Highlights: • The FP quantitative distribution in the fuel bundle is measured by gamma-spectrometry. • The FP location is obtained with emission tomograms and other experiment results. • X-ray tomograms provide the material and density mapping of the degraded bundle. • The self-attenuation may then be computed for each isotope at its key line energy. • Results are consistent with other FPT3 measurements, with acceptable uncertainties. -- Abstract: The international Phébus FP programme, initiated in 1988 by the French “Institut de Radioprotection et de Sûreté Nucléaire” (IRSN), in cooperation with the European Commission (EC) and with financial support from USNRC, Canada, PSI/HSK (Switzerland), Japan and Korea, was aimed at studying severe accident phenomena: the fuel degradation, the release of fission products (FPs) and their transport through the reactor coolant system to the containment building. The FPT3 test, conducted in 2004, was the last of the five light water reactor core meltdown accident tests performed on irradiated fuel rods. After the experiment, the test device was recovered and analysed through a full set of non-destructive examinations performed over the fuel bundle zone, including gamma-scanning, gamma emission tomography, X-ray radiography and X-ray transmission tomography. The gamma-scanning was specifically devoted to the location, identification and amount quantification of the FPs remaining in the bundle. Since the fuel bundle became highly degraded during the experiment, the geometry was different at each level examined, and did not correspond to the well-known initial state. The self-attenuation of the test device and consequently the efficiency correction could then not be estimated by classical means that need to know the geometry of the object. Using the results of the other non-destructive examinations, specific computational tools and methods have therefore been developed to compute the self-attenuation of the bundle

  1. Quantitation of regional cerebral blood flow corrected for partial volume effect using O-15 water and PET

    DEFF Research Database (Denmark)

    IIda, H.; Law, I.; Pakkenberg, B.

    2000-01-01

    Limited spatial resolution of positron emission tomography (PET) can cause significant underestimation in the observed regional radioactivity concentration (so-called partial volume effect or PVE) resulting in systematic errors in estimating quantitative physiologic parameters. The authors have...... formulated four mathematical models that describe the dynamic behavior of a freely diffusible tracer (H215O) in a region of interest (ROI) incorporating estimates of regional tissue flow that are independent of PVE. The current study was intended to evaluate the feasibility of these models and to establish...... a methodology to accurately quantify regional cerebral blood flow (CBF) corrected for PVE in cortical gray matter regions. Five monkeys were studied with PET after IV H2(15)O two times (n = 3) or three times (n = 2) in a row. Two ROIs were drawn on structural magnetic resonance imaging (MRI) scans and projected...

  2. Use of dual energy X-ray absorptiometry, the trabecular bone score and quantitative computed tomography in the evaluation of chronic kidney disease-mineral and bone disorders.

    Science.gov (United States)

    Pocock, Nicholas

    2017-03-01

    In subjects with chronic kidney disease (CKD) who suffer a minimal trauma fracture, the problem is to differentiate between osteoporosis and the various forms of renal bone disease associated with CKD-mineral and bone disorder. This problem is exacerbated by the fact that renal osteodystrophy may coexist with osteoporosis. The World Health Organization's bone mineral density (BMD) criteria for osteopenia ( -2.5 < T-score < -1.0) and osteoporosis (a T-score ≤ -2.5) may be used in patients with CKD stages 1-3. In CKD stages 4-5, BMD by dual-energy X-ray absorptiometry (DXA) is less predictive and may underestimate fracture risk. The development of absolute fracture risk (AFR) algorithms, such as FRAX® and the Garvan absolute fracture risk calculator, to predict risk of fracture over a given time (usually 10 years) aims to incorporate non-BMD risk factors into the clinical assessment. FRAX® has been shown to be useful to assess fracture risk in CKD but may underestimate fracture risk in advanced CKD. The trabecular bone score is a measure of grey scale homogeneity obtained from spine DXA, which correlates to trabecular microarchitecture and is an independent risk factor for fracture. Recent data demonstrate the potential utility of the trabecular bone score adjustment of AFR through the FRAX® algorithm in subjects with CKD. Parameters of bone microarchitecture using peripheral quantitative computed tomography (pQCT) or high-resolution pQCT are also able to discriminate fracture status in subjects with CKD. However, there are at present no convincing data that the addition of pQCT or high-resolution pQCT parameters to DXA BMD improves fracture discrimination. More advanced estimates of bone strength derived from measurements of micro-architecture, by QCT-derived finite element analysis may be incorporated into AFR algorithms in the future. © 2017 Asian Pacific Society of Nephrology.

  3. [O-methyl-{sup 11}C]{beta}-CIT-FP, a potential radioligand for quantitation of the dopamine transporter: Preparation, autoradiography, metabolite studies, and positron emission tomography examinations

    Energy Technology Data Exchange (ETDEWEB)

    Lundkvist, Camilla; Halldin, Christer; Swahn, Carl-Gunnar; Hall, Haakan; Karlsson, Per; Nakashima, Yoshifumi; Wang, Shaoyin; Milius, Richard A.; Neumeyer, John L.; Farde, Lars

    1995-10-01

    {beta}-CIT-FP [N-(3-fluoropropyl)-2{beta}-carbomethoxy-3{beta}-(4-iodophenyl)nortropane] is a cocaine analogue with a high affinity for the dopamine transporter. [O-methyl-{sup 11}C]{beta}-CIT-FP ([{sup 11}C]{beta}-CIT-FP) was prepared byO -alkylation of the free acid with [{sup 11}C]methyl iodide. The total radiochemical yield of [{sup 11}C]{beta}-CIT-FP was 50 to 60% with an overall synthesis time of 30 min. The radiochemical purity was >99%, and the specific radioactivity at time of injection was about 37 GBq/{mu}mol (1000 Ci/mmol). Autoradiographic examination of [{sup 11}C]{beta}-CIT-FP binding in human brain postmortem demonstrated specific binding in the caudate nucleus and putamen. Positron emission tomography (PET) examination of [{sup 11}C]{beta}-CIT-FP in a Cynomolgus monkey demonstrated accumulation in the striatum with a striatum-to-cerebellum ratio of about 8 after 60 min. Equilibrium in the striatum was attained within 70 to 90 min. The radioactivity ratios of thalamus/cerebellum and neocortex/cerebellum were about 2 and 1.5, respectively. In a displacement experiment, radioactivity in the striatum but not in the cerebellum was reduced after injection of {beta}-CIT, indicating that striatal radioactivity following injection of [{sup 11}C]{beta}-CIT-FP is associated with dopamine transporter sites and that the binding is reversible. The fraction of the total radioactivity in plasma representing [{sup 11}C]{beta}-CIT-FP determined by high-performance liquid chromatography (HPLC) was 84% at 15 min and 50% at 95 min. [{sup 11}C]{beta}-CIT-FP should be a useful PET radioligand for the quantitation of dopamine transporters in the human brain in vivo.

  4. Multislice quantitative computed tomography allows early detection of bone mineral density alterations induced by atherogenic diet in a growing rat experimental model

    International Nuclear Information System (INIS)

    Gubert, M.J.; Monforte, F.; Calo, C.; Lylyk, P.; Friedman, M.F.; Gamba, C.A.

    2012-01-01

    Purpose. To demonstrate the utility of Multislice Quantitative Computed Tomography (MS-QCT) in the early detection of mandibular bone mineral density (BMD) alterations induced by an atherogenic diet in a growing rat experimental model. Materials and Methods. Male weanling Wistar rats (n =16) were divided by body weight (Wt) into 2 groups: control (C) and experimental (E), with no significant differences in the mean initial Wt (p>0.05). C was fed rodent stock diet ad libitum, and E an atherogenic diet for 3 weeks (3w). Zoometry (body weight and length) and diet intake (g/100g rat/day) were monitored. At 3 w in serum (mg/dL) lipidlipoprotein profile was studied: total cholesterol (t-C), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), non-HDL cholesterol (non-HDL-C) and MSQCT (Philips 64 CT, quantified with the eFilm Workstation 2.1) in seven mandibular areas (MA): n. 1 to 4: from chin to mandibular foramen, n. 5: coronoid process, n. 6: condylar process, n. 7: angular process. Statistics: Pearson's correlation between BMD in each MA and serum t-C. p 0.05). Correlation coefficients (r) and their significance levels (p) were relevant in 5/7 MA. MA1:-0.580 (p=0.019), MA2:-0.709 (p=0.002), MA3:-0.635 (p=0.008), MA5:-0.674 (p=0.004), MA6:-0.564 (p=0.023). Conclusions. These results suggest that MS-QCT is an imaging diagnostic method that allows the early detection of mandible bone architecture alterations induced by an atherogenic diet. Inverse correlation between BMD and t-C would indicate an association between an atherogenic diet intake and potential temporomandibular disorders. (authors)

  5. Correlation of X-Ray Computed Tomography with Quantitative Nuclear Magnetic Resonance Methods for Pre-Clinical Measurement of Adipose and Lean Tissues in Living Mice

    Directory of Open Access Journals (Sweden)

    Matthew N. Metzinger

    2014-10-01

    Full Text Available Numerous obesity studies have coupled murine models with non-invasive methods to quantify body composition in longitudinal experiments, including X-ray computed tomography (CT or quantitative nuclear magnetic resonance (QMR. Both microCT and QMR have been separately validated with invasive techniques of adipose tissue quantification, like post-mortem fat extraction and measurement. Here we report a head-to-head study of both protocols using oil phantoms and mouse populations to determine the parameters that best align CT data with that from QMR. First, an in vitro analysis of oil/water mixtures was used to calibrate and assess the overall accuracy of microCT vs. QMR data. Next, experiments were conducted with two cohorts of living mice (either homogenous or heterogeneous by sex, age and genetic backgrounds to assess the microCT imaging technique for adipose tissue segmentation and quantification relative to QMR. Adipose mass values were obtained from microCT data with three different resolutions, after which the data were analyzed with different filter and segmentation settings. Strong linearity was noted between the adipose mass values obtained with microCT and QMR, with optimal parameters and scan conditions reported herein. Lean tissue (muscle, internal organs was also segmented and quantified using the microCT method relative to the analogous QMR values. Overall, the rigorous calibration and validation of the microCT method for murine body composition, relative to QMR, ensures its validity for segmentation, quantification and visualization of both adipose and lean tissues.

  6. Effect of micro-computed tomography voxel size and segmentation method on trabecular bone microstructure measures in mice

    Directory of Open Access Journals (Sweden)

    Blaine A. Christiansen

    2016-12-01

    Full Text Available Micro-computed tomography (μCT is currently the gold standard for determining trabecular bone microstructure in small animal models. Numerous parameters associated with scanning and evaluation of μCT scans can strongly affect morphologic results obtained from bone samples. However, the effect of these parameters on specific trabecular bone outcomes is not well understood. This study investigated the effect of μCT scanning with nominal voxel sizes between 6–30 μm on trabecular bone outcomes quantified in mouse vertebral body trabecular bone. Additionally, two methods for determining a global segmentation threshold were compared: based on qualitative assessment of 2D images, or based on quantitative assessment of image histograms. It was found that nominal voxel size had a strong effect on several commonly reported trabecular bone parameters, in particular connectivity density, trabecular thickness, and bone tissue mineral density. Additionally, the two segmentation methods provided similar trabecular bone outcomes for scans with small nominal voxel sizes, but considerably different outcomes for scans with larger voxel sizes. The Qualitatively Selected segmentation method more consistently estimated trabecular bone volume fraction (BV/TV and trabecular thickness across different voxel sizes, but the Histogram segmentation method more consistently estimated trabecular number, trabecular separation, and structure model index. Altogether, these results suggest that high-resolution scans be used whenever possible to provide the most accurate estimation of trabecular bone microstructure, and that the limitations of accurately determining trabecular bone outcomes should be considered when selecting scan parameters and making conclusions about inter-group variance or between-group differences in studies of trabecular bone microstructure in small animals. Keywords: Trabecular bone, Microstructure, Micro-computed tomography, Voxel size, Resolution

  7. VECTOR TOMOGRAPHY FOR THE CORONAL MAGNETIC FIELD. II. HANLE EFFECT MEASUREMENTS

    International Nuclear Information System (INIS)

    Kramar, M.; Inhester, B.; Lin, H.; Davila, J.

    2013-01-01

    In this paper, we investigate the feasibility of saturated coronal Hanle effect vector tomography or the application of vector tomographic inversion techniques to reconstruct the three-dimensional magnetic field configuration of the solar corona using linear polarization measurements of coronal emission lines. We applied Hanle effect vector tomographic inversion to artificial data produced from analytical coronal magnetic field models with equatorial and meridional currents and global coronal magnetic field models constructed by extrapolation of real photospheric magnetic field measurements. We tested tomographic inversion with only Stokes Q, U, electron density, and temperature inputs to simulate observations over large limb distances where the Stokes I parameters are difficult to obtain with ground-based coronagraphs. We synthesized the coronal linear polarization maps by inputting realistic noise appropriate for ground-based observations over a period of two weeks into the inversion algorithm. We found that our Hanle effect vector tomographic inversion can partially recover the coronal field with a poloidal field configuration, but that it is insensitive to a corona with a toroidal field. This result demonstrates that Hanle effect vector tomography is an effective tool for studying the solar corona and that it is complementary to Zeeman effect vector tomography for the reconstruction of the coronal magnetic field

  8. Investigation of the self tempering effect of martensite by means of atom probe tomography

    International Nuclear Information System (INIS)

    Sackl, Stephanie; Clemens, Helmut; Primig, Sophie

    2015-01-01

    Self-tempering effects can be observed in steels with relatively high martensite start temperatures. After the formation of the first martensitic laths, carbon is able to diffuse in these laths during cooling, which can be attributed to sufficiently high temperatures. This effect cannot be observed in laths formed at lower temperatures. In steels containing up to 0.2 m.-% carbon, up to 90 % of the carbon atoms in the martensite segregate to dislocations during quenching. Due to its atomic resolution and sensitivity with respect to light elements, atom probe tomography is very well suited for the investigation of this phenomenon. In this study, the self-tempering effect in a quenched and tempered steel 42CrMo4 with a martensite start temperature of 310 C is investigated by means of atom probe tomography.

  9. The effect of iterative reconstruction on computed tomography assessment of emphysema, air trapping and airway dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Mets, Onno M.; Willemink, Martin J.; Kort, Freek P.L. de; Leiner, Tim; Jong, Pim A. de [UMC Utrecht, Department of Radiology, P.O. Box 85500, GA, Utrecht (Netherlands); Mol, Christian P. [Utrecht University Medical Center, Image Sciences Institute, Utrecht (Netherlands); Oudkerk, Matthijs [Groningen University Medical Center, Department of Radiology, Groningen (Netherlands); Prokop, Mathias [Nijmegen University Medical Center, Department of Radiology, Nijmegen (Netherlands)

    2012-10-15

    To determine the influence of iterative reconstruction (IR) on quantitative computed tomography (CT) measurements of emphysema, air trapping, and airway wall and lumen dimensions, compared to filtered back-projection (FBP). Inspiratory and expiratory chest CTs of 75 patients (37 male, 38 female; mean age 64.0 {+-} 5.7 years) were reconstructed using FBP and IR. CT emphysema, CT air trapping and airway dimensions of a segmental bronchus were quantified using several commonly used quantification methods. The two algorithms were compared using the concordance correlation coefficient (p{sub c}) and Wilcoxon signed rank test. Only the E/I-ratio{sub MLD} as a measure of CT air trapping and airway dimensions showed no significant differences between the algorithms, whereas all CT emphysema and the other CT air trapping measures were significantly different at IR when compared to FBP (P < 0.001). The evaluated IR algorithm significantly influences quantitative CT measures in the assessment of emphysema and air trapping. However, the E/I-ratio{sub MLD} as a measure of CT air trapping, as well as the airway measurements, is unaffected by this reconstruction method. Quantitative CT of the lungs should be performed with careful attention to the CT protocol, especially when iterative reconstruction is introduced. (orig.)

  10. Skype Synchronous Interaction Effectiveness in a Quantitative Management Science Course

    Science.gov (United States)

    Strang, Kenneth David

    2012-01-01

    An experiment compared asynchronous versus synchronous instruction in an online quantitative course. Mann-Whitney U-tests, correlation, analysis of variance, t tests, and multivariate analysis of covariance (MANCOVA) were utilized to test the hypothesis that more high-quality online experiential learning interactions would increase grade.…

  11. Reporting and Interpreting Effect Size in Quantitative Agricultural Education Research

    Science.gov (United States)

    Kotrlik, Joe W.; Williams, Heather A.; Jabor, M. Khata

    2011-01-01

    The Journal of Agricultural Education (JAE) requires authors to follow the guidelines stated in the Publication Manual of the American Psychological Association [APA] (2009) in preparing research manuscripts, and to utilize accepted research and statistical methods in conducting quantitative research studies. The APA recommends the reporting of…

  12. Effective doses to patients undergoing thoracic computed tomography examinations.

    Science.gov (United States)

    Huda, W; Scalzetti, E M; Roskopf, M

    2000-05-01

    The purpose of this study was to investigate how x-ray technique factors and effective doses vary with patient size in chest CT examinations. Technique factors (kVp, mAs, section thickness, and number of sections) were recorded for 44 patients who underwent a routine chest CT examination. Patient weights were recorded together with dimensions and mean Hounsfield unit values obtained from representative axial CT images. The total mass of directly irradiated patient was modeled as a cylinder of water to permit the computation of the mean patient dose and total energy imparted for each chest CT examination. Computed values of energy imparted during the chest CT examination were converted into effective doses taking into account the patient weight. Patient weights ranged from 4.5 to 127 kg, and half the patients in this study were children under 18 years of age. All scans were performed at 120 kVp with a 1 s scan time. The selected tube current showed no correlation with patient weight (r2=0.06), indicating that chest CT examination protocols do not take into account for the size of the patient. Energy imparted increased with increasing patient weight, with values of energy imparted for 10 and 70 kg patients being 85 and 310 mJ, respectively. The effective dose showed an inverse correlation with increasing patient weight, however, with values of effective dose for 10 and 70 kg patients being 9.6 and 5.4 mSv, respectively. Current CT technique factors (kVp/mAs) used to perform chest CT examinations result in relatively high patient doses, which could be reduced by adjusting technique factors based on patient size.

  13. Quantitation: clinical applications

    International Nuclear Information System (INIS)

    Britton, K.E.

    1982-01-01

    Single photon emission tomography may be used quantitatively if its limitations are recognized and quantitation is made in relation to some reference area on the image. Relative quantitation is discussed in outline in relation to the liver, brain and pituitary, thyroid, adrenals, and heart. (U.K.)

  14. Effect of tissue heterogeneity on quantification in positron emission tomography

    International Nuclear Information System (INIS)

    Blomqvist, G.; Lammertsma, A.A.; Mazoyer, B.; Wienhard, K.

    1995-01-01

    As a result of the limited spatial resolution of positron emission tomographic scanners, the measurements of physiological parameters are compromised by tissue heterogeneity. The effect of tissue heterogeneity on a number of parameters was studied by simulation and an analytical method. Five common tracer models were assessed. The input and tissue response functions were assumed to be free from noise and systematic errors. The kinetic model was assumed to be perfect. Two components with different kinetics were mixed in different proportions and contrast with respect to the model parameters. Different experimental protocols were investigated. Of three methods investigated for the measurement of cerebral blood flow (CBF) (steady state, dynamic, integral), the second one was least sensitive to errors caused by tissue heterogeneity and the main effect was an underestimation of the distribution volume. With the steady state method, errors in oxygen extraction fraction caused by tissue heterogeneity were always found to be less than the corresponding errors in CBF. For myocardial blood flow the steady state method was found to perform better than the bolus method. The net accumulation of substrate (i.e. rCMR glc in the case of glucose analogs) was found to be comparatively insensitive to tissue heterogeneity. Individual rate constans such as k 2 and k 3 for efflux and metabolism of the substrate in the pool of unmetabolized substrate in the tissue, respectively, were found to be more sensitive. In studies of radioligand binding, using only tracer doses, the effect of tissue heterogeneity on the parameter k on .B max could be considerable. In studies of radioligand binding using a protocol with two experiments, one with high and one with low specific activity, B max was found to be insensitive while K d was very sensitive to tissue heterogeneity. (orig.)

  15. Effect of tissue heterogeneity on quantification in positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Blomqvist, G [Dept. of Clinical Neuroscience, Experimental Alcohol and Drug Addiction Research Section, Karolinska Hospital, Stockholm (Sweden); Lammertsma, A A [PET Methodology Group, Cyclotron Unit, MRC Clinical Sciences Centre, Royal Postgraduate Medical School, Hammersmith Hospital, London (United Kingdom); Mazoyer, B [Service Hospitalier Frederic Joliot CEA/Dept. de Biologie, Hopital d` Orsay and Antenne d` Informatique Medicale, Hopital Robert Debre, Paris (France); Wienhard, K [Max-Planck-Inst. fuer Neurologische Forschung, Koeln (Germany)

    1995-07-01

    As a result of the limited spatial resolution of positron emission tomographic scanners, the measurements of physiological parameters are compromised by tissue heterogeneity. The effect of tissue heterogeneity on a number of parameters was studied by simulation and an analytical method. Five common tracer models were assessed. The input and tissue response functions were assumed to be free from noise and systematic errors. The kinetic model was assumed to be perfect. Two components with different kinetics were mixed in different proportions and contrast with respect to the model parameters. Different experimental protocols were investigated. Of three methods investigated for the measurement of cerebral blood flow (CBF) (steady state, dynamic, integral), the second one was least sensitive to errors caused by tissue heterogeneity and the main effect was an underestimation of the distribution volume. With the steady state method, errors in oxygen extraction fraction caused by tissue heterogeneity were always found to be less than the corresponding errors in CBF. For myocardial blood flow the steady state method was found to perform better than the bolus method. The net accumulation of substrate (i.e. rCMR{sub glc} in the case of glucose analogs) was found to be comparatively insensitive to tissue heterogeneity. Individual rate constans such as k{sub 2} and k{sub 3} for efflux and metabolism of the substrate in the pool of unmetabolized substrate in the tissue, respectively, were found to be more sensitive. In studies of radioligand binding, using only tracer doses, the effect of tissue heterogeneity on the parameter k{sub on}.B{sub max} could be considerable. In studies of radioligand binding using a protocol with two experiments, one with high and one with low specific activity, B{sub max} was found to be insensitive while K{sub d} was very sensitive to tissue heterogeneity. (orig.)

  16. Quantitative SPECT brain imaging: Effects of attenuation and detector response

    International Nuclear Information System (INIS)

    Gilland, D.R.; Jaszczak, R.J.; Bowsher, J.E.; Turkington, T.G.; Liang, Z.; Greer, K.L.; Coleman, R.E.

    1993-01-01

    Two physical factors that substantially degrade quantitative accuracy in SPECT imaging of the brain are attenuation and detector response. In addition to the physical factors, random noise in the reconstructed image can greatly affect the quantitative measurement. The purpose of this work was to implement two reconstruction methods that compensate for attenuation and detector response, a 3D maximum likelihood-EM method (ML) and a filtered backprojection method (FB) with Metz filter and Chang attenuation compensation, and compare the methods in terms of quantitative accuracy and image noise. The methods were tested on simulated data of the 3D Hoffman brain phantom. The simulation incorporated attenuation and distance-dependent detector response. Bias and standard deviation of reconstructed voxel intensities were measured in the gray and white matter regions. The results with ML showed that in both the gray and white matter regions as the number of iterations increased, bias decreased and standard deviation increased. Similar results were observed with FB as the Metz filter power increased. In both regions, ML had smaller standard deviation than FB for a given bias. Reconstruction times for the ML method have been greatly reduced through efficient coding, limited source support, and by computing attenuation factors only along rays perpendicular to the detector

  17. Quantitative prediction of drug side effects based on drug-related features.

    Science.gov (United States)

    Niu, Yanqing; Zhang, Wen

    2017-09-01

    Unexpected side effects of drugs are great concern in the drug development, and the identification of side effects is an important task. Recently, machine learning methods are proposed to predict the presence or absence of interested side effects for drugs, but it is difficult to make the accurate prediction for all of them. In this paper, we transform side effect profiles of drugs as their quantitative scores, by summing up their side effects with weights. The quantitative scores may measure the dangers of drugs, and thus help to compare the risk of different drugs. Here, we attempt to predict quantitative scores of drugs, namely the quantitative prediction. Specifically, we explore a variety of drug-related features and evaluate their discriminative powers for the quantitative prediction. Then, we consider several feature combination strategies (direct combination, average scoring ensemble combination) to integrate three informative features: chemical substructures, targets, and treatment indications. Finally, the average scoring ensemble model which produces the better performances is used as the final quantitative prediction model. Since weights for side effects are empirical values, we randomly generate different weights in the simulation experiments. The experimental results show that the quantitative method is robust to different weights, and produces satisfying results. Although other state-of-the-art methods cannot make the quantitative prediction directly, the prediction results can be transformed as the quantitative scores. By indirect comparison, the proposed method produces much better results than benchmark methods in the quantitative prediction. In conclusion, the proposed method is promising for the quantitative prediction of side effects, which may work cooperatively with existing state-of-the-art methods to reveal dangers of drugs.

  18. Quantitative analysis of pulmonary artery and pulmonary collaterals in preoperative patients with pulmonary artery atresia using dual-source computed tomography

    International Nuclear Information System (INIS)

    Yin Lei; Lu, Bin; Han Lei; Wu Runze; Johnson, Laura; Xu Zhongying; Jiang Shiliang; Dai Ruping

    2011-01-01

    Objective: To evaluate the value of dual-source computed tomography (DSCT) in quantitatively measuring pulmonary arteries and major aortopulmonary collateral vessels in comparison with conventional angiographic (CA) on preoperative patients with pulmonary artery atresia and ventricular septal defect (PAA-VSD). Materials and methods: Twenty PAA-VSD patients who had complete imaging data of DSCT, CA and echocardiography (ECHO) studies were retrospectively analyzed. Using final clinical diagnosis as the standard, results of DSCT, CA and ECHO on the detection of cardiac malformations, measurement of diameters of pulmonary artery and collateral vessel, as well as the values of McGoon ratio, pulmonary arterial index (PAI) and total neopulmonary arterial index (TNPAI) were derived and compared. Results: In 20 patients, 51 of 54 (94.4%) cardiac malformations were visualized by DSCT, whereas 42 (77.8%) by ECHO (p = 0.027). Fourteen cases with aortopulmonary collateral vessels were all (100%) detected by DSCT, whereas 5 cases (35.7%) by ECHO (p = 0.001), and 13 cases (92.9%) by CA (p = 0.995). Sixteen cases with confluence of native pulmonary arteries were diagnosed by DSCT, whereas 10 cases by CA (p = 0.024). Measurement of the diameters of pulmonary arteries, collateral vessels, and descending aorta at the level of diaphragm were correlated well between DSCT and CA (r = 0.95-0.99). McGoon ratio (DSCT = 1.18 ± 0.60, CA = 1.23 ± 0.64), PAI (DSCT = 130.96 ± 99.38 mm 2 /m 2 , CA = 140.91 ± 107.87 mm 2 /m 2 ) and TNPAI (DSCT = 160.31 ± 125.62 mm 2 /m 2 , CA = 169.14 ± 122.81 mm 2 /m 2 ) were calculated respectively, without significant differences between DSCT and CA by paired t-tests (all p > 0.05). Conclusion: DSCT was efficient for evaluating and measuring native pulmonary artery and aortopulmonary collateral vessels prior to surgical procedures in PAA-VSD patients. Combined with echocardiography, DSCT showed potential to replace CA for evaluating pulmonary artery

  19. Multivariate analysis of quantitative traits can effectively classify rapeseed germplasm

    Directory of Open Access Journals (Sweden)

    Jankulovska Mirjana

    2014-01-01

    Full Text Available In this study, the use of different multivariate approaches to classify rapeseed genotypes based on quantitative traits has been presented. Tree regression analysis, PCA analysis and two-way cluster analysis were applied in order todescribe and understand the extent of genetic variability in spring rapeseed genotype by trait data. The traits which highly influenced seed and oil yield in rapeseed were successfully identified by the tree regression analysis. Principal predictor for both response variables was number of pods per plant (NP. NP and 1000 seed weight could help in the selection of high yielding genotypes. High values for both traits and oil content could lead to high oil yielding genotypes. These traits may serve as indirect selection criteria and can lead to improvement of seed and oil yield in rapeseed. Quantitative traits that explained most of the variability in the studied germplasm were classified using principal component analysis. In this data set, five PCs were identified, out of which the first three PCs explained 63% of the total variance. It helped in facilitating the choice of variables based on which the genotypes’ clustering could be performed. The two-way cluster analysissimultaneously clustered genotypes and quantitative traits. The final number of clusters was determined using bootstrapping technique. This approach provided clear overview on the variability of the analyzed genotypes. The genotypes that have similar performance regarding the traits included in this study can be easily detected on the heatmap. Genotypes grouped in the clusters 1 and 8 had high values for seed and oil yield, and relatively short vegetative growth duration period and those in cluster 9, combined moderate to low values for vegetative growth duration and moderate to high seed and oil yield. These genotypes should be further exploited and implemented in the rapeseed breeding program. The combined application of these multivariate methods

  20. Detection of hemodynamic impairment using magnetic resonance angiography in patients with internal carotid artery stenoocclusive disease. Comparison with quantitative brain perfusion single-photon emission computed tomography

    International Nuclear Information System (INIS)

    Hirooka, Ryonoshin; Ogasawara, Kuniaki

    2008-01-01

    Cerebrovascular reactivity (CVR) to acetazolamideis a key parameter in determining the severity of hemodynamic impairment in patients with major cerebral artery occlusive disease. The aim of the present study is to validate the accuracy of magnetic resonance angiography (MRA) for detecting hemodynamic impairment by correlating detectability of the middle cerebral artery obtained by MRA with CVR measured by single-photon emission computed tomography (SPECT) in patients with internal carotid artery (ICA) occlusive disease. Ninety-four patients with chronic ICA occlusion underwent single slab three-dimensional time-of-flight MRA and SPECT. SPECT-CVR was calculated by measured cerebral blood flow before and after acetazolamide challenge. CVR was significantly lower in patients without detection of any portion (M1, M2 or M3) of the MCA than in those with detection of all portions. When SPECT-CVR lower than the mean- 2 standard deviation (SD) obtained in normal subjects was defined as reduced and the SPECT-CVR was assumed as the true determinant of hemodynamic impairment, MRA provided 92% sensitivity and 73% specificity, with 96% negative predictive value for detecting patients with reduced CVR. The present MRA method is effective for the identification of patients with hemodynamic impairment. (author)

  1. Computed Tomography Imaging of a Hip Prosthesis Using Iterative Model-Based Reconstruction and Orthopaedic Metal Artefact Reduction: A Quantitative Analysis.

    Science.gov (United States)

    Wellenberg, Ruud H H; Boomsma, Martijn F; van Osch, Jochen A C; Vlassenbroek, Alain; Milles, Julien; Edens, Mireille A; Streekstra, Geert J; Slump, Cornelis H; Maas, Mario

    To quantify the combined use of iterative model-based reconstruction (IMR) and orthopaedic metal artefact reduction (O-MAR) in reducing metal artefacts and improving image quality in a total hip arthroplasty phantom. Scans acquired at several dose levels and kVps were reconstructed with filtered back-projection (FBP), iterative reconstruction (iDose) and IMR, with and without O-MAR. Computed tomography (CT) numbers, noise levels, signal-to-noise-ratios and contrast-to-noise-ratios were analysed. Iterative model-based reconstruction results in overall improved image quality compared to iDose and FBP (P < 0.001). Orthopaedic metal artefact reduction is most effective in reducing severe metal artefacts improving CT number accuracy by 50%, 60%, and 63% (P < 0.05) and reducing noise by 1%, 62%, and 85% (P < 0.001) whereas improving signal-to-noise-ratios by 27%, 47%, and 46% (P < 0.001) and contrast-to-noise-ratios by 16%, 25%, and 19% (P < 0.001) with FBP, iDose, and IMR, respectively. The combined use of IMR and O-MAR strongly improves overall image quality and strongly reduces metal artefacts in the CT imaging of a total hip arthroplasty phantom.

  2. Quantitative Ultrasound Characterization of Cancer Radiotherapy Effects In Vitro

    International Nuclear Information System (INIS)

    Vlad, Roxana M.; Alajez, Nehad M.; Giles, Anoja B.Sc.; Kolios, Michael C.; Czarnota, Gregory J.

    2008-01-01

    Purpose: Currently, no routinely used imaging modality is available to assess tumor responses to cancer treatment within hours to days after radiotherapy. In this study, we demonstrate the preclinical application of quantitative ultrasound methods to characterize the cellular responses to cancer radiotherapy in vitro. Methods and Materials: Three different cell lines were exposed to radiation doses of 2-8 Gy. Data were collected with an ultrasound scanner using frequencies of 10-30 MHz. As indicators of response, ultrasound integrated backscatter and spectral slope were determined from the cell samples. These parameters were corrected for ultrasonic attenuation by measuring the attenuation coefficient. Results: A significant increase in the ultrasound integrated backscatter of 4-7 dB (p < 0.001) was found for radiation-treated cells compared with viable cells at all radiation doses. The spectral slopes decreased in the cell samples that predominantly underwent mitotic arrest/catastrophe after radiotherapy, consistent with an increase in cell size. In contrast, the spectral slopes did not change significantly in the cell samples that underwent a mix of cell death (apoptosis and mitotic arrest), with no significant change in average cell size. Conclusion: The changes in ultrasound integrated backscatter and spectral slope were direct consequences of cell and nuclear morphologic changes associated with cell death. The results indicate that this combination of quantitative ultrasonic parameters has the potential to assess the cell responses to radiation, differentiate between different types of cell death, and provide a preclinical framework to monitor tumor responses in vivo

  3. The effect of iterative reconstruction on computed tomography assessment of emphysema, air trapping and airway dimensions

    International Nuclear Information System (INIS)

    Mets, Onno M.; Willemink, Martin J.; Kort, Freek P.L. de; Leiner, Tim; Jong, Pim A. de; Mol, Christian P.; Oudkerk, Matthijs; Prokop, Mathias

    2012-01-01

    To determine the influence of iterative reconstruction (IR) on quantitative computed tomography (CT) measurements of emphysema, air trapping, and airway wall and lumen dimensions, compared to filtered back-projection (FBP). Inspiratory and expiratory chest CTs of 75 patients (37 male, 38 female; mean age 64.0 ± 5.7 years) were reconstructed using FBP and IR. CT emphysema, CT air trapping and airway dimensions of a segmental bronchus were quantified using several commonly used quantification methods. The two algorithms were compared using the concordance correlation coefficient (p c ) and Wilcoxon signed rank test. Only the E/I-ratio MLD as a measure of CT air trapping and airway dimensions showed no significant differences between the algorithms, whereas all CT emphysema and the other CT air trapping measures were significantly different at IR when compared to FBP (P MLD as a measure of CT air trapping, as well as the airway measurements, is unaffected by this reconstruction method. Quantitative CT of the lungs should be performed with careful attention to the CT protocol, especially when iterative reconstruction is introduced. (orig.)

  4. Effect of Novel Amplitude/Phase Binning Algorithm on Commercial Four-Dimensional Computed Tomography Quality

    International Nuclear Information System (INIS)

    Olsen, Jeffrey R.; Lu Wei; Hubenschmidt, James P.; Nystrom, Michelle M.; Klahr, Paul; Bradley, Jeffrey D.; Low, Daniel A.; Parikh, Parag J.

    2008-01-01

    Purpose: Respiratory motion is a significant source of anatomic uncertainty in radiotherapy planning and can result in errors of portal size and the subsequent radiation dose. Although four-dimensional computed tomography allows for more accurate analysis of the respiratory cycle, breathing irregularities during data acquisition can cause considerable image distortions. The aim of this study was to examine the effect of respiratory irregularities on four-dimensional computed tomography, and to evaluate a novel image reconstruction algorithm using percentile-based tagging of the respiratory cycle. Methods and Materials: Respiratory-correlated helical computed tomography scans were acquired for 11 consecutive patients. The inspiration and expiration data sets were reconstructed using the default phase-based method, as well as a novel respiration percentile-based method with patient-specific metrics to define the ranges of the reconstruction. The image output was analyzed in a blinded fashion for the phase- and percentile-based reconstructions to determine the prevalence and severity of the image artifacts. Results: The percentile-based algorithm resulted in a significant reduction in artifact severity compared with the phase-based algorithm, although the overall artifact prevalence did not differ between the two algorithms. The magnitude of differences in respiratory tag placement between the phase- and percentile-based algorithms correlated with the presence of image artifacts. Conclusion: The results of our study have indicated that our novel four-dimensional computed tomography reconstruction method could be useful in detecting clinically relevant image distortions that might otherwise go unnoticed and to reduce the image distortion associated with some respiratory irregularities. Additional work is necessary to assess the clinical impact on areas of possible irregular breathing

  5. Effect of The Measuring Parameters on The Reconstructed Images by Computerized Tomography

    International Nuclear Information System (INIS)

    Ali, A.M.; Ali, A.M.; Megahid, R.M.

    2011-01-01

    In this paper, the potential of computerized tomography by neutrons and gamma rays as a main precise technique for nondestructive assay of materials and components of prime importance in nuclear and general industries are given and discussed. Both Fast Fourier Transform (FFT) and convolution techniques are introduced. Shepp and Logan human head phantom is used for theoretical testing and studying the effect of translation value for both techniques. Moreover, the effect of the projection number discussed. Comparison between the two reconstruction techniques wasper formed for the examined object. In addition, some of the experimentally scanned images using slit beam of gamma rays emitt ed from the ETRR- 1 reactor are presented and discussed.

  6. Concept of effective atomic number and effective mass density in dual-energy X-ray computed tomography

    International Nuclear Information System (INIS)

    Bonnin, Anne; Duvauchelle, Philippe; Kaftandjian, Valérie; Ponard, Pascal

    2014-01-01

    This paper focuses on dual-energy X-ray computed tomography and especially the decomposition of the measured attenuation coefficient in a mass density and atomic number basis. In particular, the concept of effective atomic number is discussed. Although the atomic number is well defined for chemical elements, the definition of an effective atomic number for any compound is not an easy task. After reviewing different definitions available in literature, a definition related to the method of measurement and X-ray energy, is suggested. A new concept of effective mass density is then introduced in order to characterize material from dual-energy computed tomography. Finally, this new concept and definition are applied on a simulated case, focusing on explosives identification in luggage

  7. Effect of computed tomography noise and tissue heterogeneity on cerebral blood flow determination by xenon-enhanced computed tomography

    International Nuclear Information System (INIS)

    Good, W.F.; Gur, D.

    1987-01-01

    The errors associated with derivation of cerebral blood flow values by the xenon-enhanced computed tomography (CT) method have been evaluated as a function of tissue heterogeneity and CT noise. The results of this study indicate that CT noise introduces large errors in the derived flow value when data for a single, unprocessed voxel are used for this purpose. CT noise increases the derived flow values in a systematic way. Tissue heterogeneity results in a systematic error which lowers the derived flow values. Errors due to both parameters are computed for typical and extreme conditions

  8. Effects of Respiration-Averaged Computed Tomography on Positron Emission Tomography/Computed Tomography Quantification and its Potential Impact on Gross Tumor Volume Delineation

    International Nuclear Information System (INIS)

    Chi, Pai-Chun Melinda; Mawlawi, Osama; Luo Dershan; Liao Zhongxing; Macapinlac, Homer A.; Pan Tinsu

    2008-01-01

    Purpose: Patient respiratory motion can cause image artifacts in positron emission tomography (PET) from PET/computed tomography (CT) and change the quantification of PET for thoracic patients. In this study, respiration-averaged CT (ACT) was used to remove the artifacts, and the changes in standardized uptake value (SUV) and gross tumor volume (GTV) were quantified. Methods and Materials: We incorporated the ACT acquisition in a PET/CT session for 216 lung patients, generating two PET/CT data sets for each patient. The first data set (PET HCT /HCT) contained the clinical PET/CT in which PET was attenuation corrected with a helical CT (HCT). The second data set (PET ACT /ACT) contained the PET/CT in which PET was corrected with ACT. We quantified the differences between the two datasets in image alignment, maximum SUV (SUV max ), and GTV contours. Results: Of the patients, 68% demonstrated respiratory artifacts in the PET HCT , and for all patients the artifact was removed or reduced in the corresponding PET ACT . The impact of respiration artifact was the worst for lesions less than 50 cm 3 and located below the dome of the diaphragm. For lesions in this group, the mean SUV max difference, GTV volume change, shift in GTV centroid location, and concordance index were 21%, 154%, 2.4 mm, and 0.61, respectively. Conclusion: This study benchmarked the differences between the PET data with and without artifacts. It is important to pay attention to the potential existence of these artifacts during GTV contouring, as such artifacts may increase the uncertainties in the lesion volume and the centroid location

  9. Quantitative analysis of adenosine A{sub 1} receptors in human brain using positron emission tomography and [1 -methyl-{sup 11}C]8-dicyclopropylmethyl-1-methyl-3-propylxanthine

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Yuichi [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1, Naka, Itabashi, Tokyo, 173-0022 (Japan)]. E-mail: ukimura@ieee.org; Ishii, Kenji [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1, Naka, Itabashi, Tokyo, 173-0022 (Japan); Fukumitsu, Nobuyoshi [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1, Naka, Itabashi, Tokyo, 173-0022 (Japan); Department of Radiation Oncology, University of Tsukuba Hospital, Amakubo, 2-1-1, Tsukuba, 305-8576 (Japan); Oda, Keiichi [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1, Naka, Itabashi, Tokyo, 173-0022 (Japan); Sasaki, Toru [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1, Naka, Itabashi, Tokyo, 173-0022 (Japan); Kawamura, Kazunori [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1, Naka, Itabashi, Tokyo, 173-0022 (Japan); SHI Accelerator Service Ltd., 1-17-6, Ohsaki, Shinagawa, Tokyo, 141-0032 (Japan); Ishiwata, Kiichi [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, 1-1, Naka, Itabashi, Tokyo, 173-0022 (Japan)

    2004-11-01

    Fully quantitative analysis of the adenosine A{sub 1} receptor (A1R) in the brain with {sup 11}C-MPDX and positron emission tomography is reported. The kinetics is described using a two-tissue three-compartment model, and estimated binding potentials correspond well with the estimates made by Logan plot. The image of the binding potential of the MPDX is physiologically reasonable. We conclude that MPDX is applicable to the visualization of the A1Rs in the brain with Logan plot.

  10. Comparative assessments of the effects of alcohol exposure on fetal brain development using optical coherence tomography and ultrasound imaging

    Science.gov (United States)

    Sudheendran, Narendran; Bake, Shameena; Miranda, Rajesh C.; Larin, Kirill V.

    2013-02-01

    The developing fetal brain is vulnerable to a variety of environmental agents including maternal ethanol consumption. Preclinical studies on the development and amelioration of fetal teratology would be significantly facilitated by the application of high resolution imaging technologies like optical coherence tomography (OCT) and high-frequency ultrasound (US). This study investigates the ability of these imaging technologies to measure the effects of maternal ethanol exposure on brain development, ex vivo, in fetal mice. Pregnant mice at gestational day 12.5 were administered ethanol (3 g/Kg b.wt.) or water by intragastric gavage, twice daily for three consecutive days. On gestational day 14.5, fetuses were collected and imaged. Three-dimensional images of the mice fetus brains were obtained by OCT and high-resolution US, and the volumes of the left and right ventricles of the brain were measured. Ethanol-exposed fetuses exhibited a statistically significant, 2-fold increase in average left and right ventricular volumes compared with the ventricular volume of control fetuses, with OCT-derived measures of 0.38 and 0.18 mm3, respectively, whereas the boundaries of the fetal mouse lateral ventricles were not clearly definable with US imaging. Our results indicate that OCT is a useful technology for assessing ventriculomegaly accompanying alcohol-induced developmental delay. This study clearly demonstrated advantages of using OCT for quantitative assessment of embryonic development compared with US imaging.

  11. The Effect of Ignoring Earth Curvature on Near-Regional Traveltime Tomography and Earthquake Hypocentral Determination

    Science.gov (United States)

    Bai, Chao-ying; Li, Xing-wang; Wang, Di; Greenhalgh, Stewart

    2017-12-01

    Earthquake hypocenter determination and traveltime tomography with local earthquake data are normally conducted using a Cartesian coordinate system and assuming a flat Earth model, but for regional and teleseismic data Earth curvature is incorporated and a spherical coordinate system employed. However, when the study region is from the local to near-regional scale (1°-4°), it is unclear what coordinate system to use and what kind of incorrect anomalies or location errors might arise when using the Cartesian coordinate frame. In this paper we investigate in a quantitative sense through two near-regional crustal models and five different inversion methods, the hypocenter errors, reflector perturbation and incorrect velocity anomalies that can arise due to the selection of the wrong coordinate system and inversion method. The simulated inversion results show that the computed traveltime errors are larger than 0.1 s when the epicentral distance exceeds 150 km, and increases linearly with increasing epicentral distance. Such predicted traveltime errors will result in different patterns of incorrect velocity anomalous structures, a perturbed Moho interface for traveltime tomography and source position which deviate for earthquake locations. The maximum magnitude of a velocity image artifact is larger than 1.0% for an epicentral distance of less than 500 km and is up to 0.9% for epicentral distances of less than 300 km. The earthquake source location error is more than 2.0 km for epicentral distances less than 500 km and is up to 1.5 km for epicentral distances less than 300 km. The Moho depth can be in error by up 1.0 km for epicentral distances of less than 500 km but is less than 0.5 km at distances below 300 km. We suggest that spherical coordinate geometry (or time correction) be used whenever there are ray paths at epicentral distances in excess of 150 km.

  12. Quantitative Nuclear Medicine. Chapter 17

    Energy Technology Data Exchange (ETDEWEB)

    Ouyang, J.; El Fakhri, G. [Massachusetts General Hospital and Harvard Medical School, Boston (United States)

    2014-12-15

    Planar imaging is still used in clinical practice although tomographic imaging (single photon emission computed tomography (SPECT) and positron emission tomography (PET)) is becoming more established. In this chapter, quantitative methods for both imaging techniques are presented. Planar imaging is limited to single photon. For both SPECT and PET, the focus is on the quantitative methods that can be applied to reconstructed images.

  13. Doppler Tomography

    Science.gov (United States)

    Marsh, T. R.

    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 accretion disc or stream. I discuss all of these and finish with some musings on possible future directions for the method. At the end I include a tabulation of Doppler maps published in refereed journals.

  14. Comparison of resting β-methyl-iodophenyl pentadecanoic acid (BMIPP) and thallium-201 tomography using quantitative polar maps in patients with unstable angina

    International Nuclear Information System (INIS)

    Suzuki, Akio; Takada, Yasuo; Nagasaka, Makoto; Kato, Rinya; Watanabe, Toshiya; Shimokata, Keiko; Yasui, Shoji

    1997-01-01

    We compared resting β-methyl-iodophenyl pentadecanoic acid (BMIPP) tomography with resting thallium-201 tomography in 28 patients with unstable angina. Tracer distribution was displayed on a polar map and compared with a normal standard deviation map obtained from a group of 12 normal subjects. The extent scores and severity scores obtained by BMIPP were significantly greater than those obtained by thallium-201. Confirmation by coronary angiography revealed the sensitivity of the methods in identifying patients to be 89% for BMIPP and 54% for thallium-201. There were significant differences between BMIPP and thallium-201 in the sensitivities of detecting postischemic jeopardized myocardium in the area supplied by the right coronary artery (RCA; 53% vs 18%, p<0.05), left circumflex artery (LCX; 78% vs 39%, p<0.025) and all 3 vessels combined (71% vs 35%, p<0.001) but no significant differences in specificity (RCA: 82% vs 64%; LCX: 70% vs 90%; and total 3 vessels combined: 75% vs 79%). In conclusion, resting BMIPP tomography is more sensitive than resting thallium-201 tomography in detecting postischemic myocardial damage in patients with unstable angina. (author)

  15. Whole-body positron emission tomography using fluorodeoxyglucose for staging of lymphoma: effectiveness and comparison with computed tomography

    International Nuclear Information System (INIS)

    Stumpe, K.D.M.; Urbinelli, M.; Steinert, H.C.; Glanzmann, C.; Buck, A.; Schulthess, G.K. von

    1998-01-01

    The purpose of this study was to evaluate whole-body positron emission tomography (WB-PET) as a staging modality in Hodgkin's disease (HD) and non-Hodgkin lymphoma (NHL) and to compare it with computed tomography (CT) in a retrospective study. Seventy-one WB-PET studies using fluorodeoxyglucose (FDG) and 49 CT examinations were performed in 19 women and 31 men. Transaxial images were acquired and reformatted coronally and sagittally in PET. CT sections were obtained from the skull base to the pelvic floor. The written reports of the imaging data were compared with a reference standard constructed on the basis of all the data on the individual patients, including clinical follow-up of at least 6 months. The sensitivity and specificity of PET were, respectively, 86% and 96% for HD (n=53), and 89% and 100% for NHL (n=18). For CT sensitivity and specificity were 81% and 41% for HD (n=33) and 86% and 67% for NHL (n=16). Differences between PET and CT sensitivities were not significant, while in HD there was a significant difference in the specificity of PET and CT examinations, mainly because CT was unable to distinguish between active or recurrent disease and residual scar tissue after therapy. FDG tumour uptake was found in high- as well as low-grade NHL patients. In conclusion, PET appears to be highly sensitive and specific for staging of lymphoma. It is at least as sensitive as CT, and more specific, particularly in patients undergoing restaging, where a well-recognized diagnostic dilemma in CT is the presence of a post-therapeutic residual mass. (orig.)

  16. A quantitative method for Failure Mode and Effects Analysis

    NARCIS (Netherlands)

    Braaksma, Anne Johannes Jan; Meesters, A.J.; Klingenberg, W.; Hicks, C.

    2012-01-01

    Failure Mode and Effects Analysis (FMEA) is commonly used for designing maintenance routines by analysing potential failures, predicting their effect and facilitating preventive action. It is used to make decisions on operational and capital expenditure. The literature has reported that despite its

  17. Positron emission tomography

    International Nuclear Information System (INIS)

    Wienhard, K.; Heiss, W.D.

    1984-01-01

    The principles and selected clinical applications of positron emission tomography are described. In this technique a chemical compound is labeled with a positron emitting isotope and its biochemical pathway is traced by coincidence detection of the two annihilation photons. The application of the techniques of computed tomography allows to reconstruct the spatial distribution of the radioactivity within a subject. The 18 F-deoxyglucose method for quantitative measurement of local glucose metabolism is discussed in order to illustrate the possibilities of positron emission tomography to record physiological processes in vivo. (orig.) [de

  18. 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Accuracy in the Staging of Non-Small Cell Lung Cancer: Review and Cost-Effectiveness

    International Nuclear Information System (INIS)

    Gómez León, Nieves; Escalona, Sofía; Bandrés, Beatriz; Belda, Cristobal; Callejo, Daniel; Blasco, Juan Antonio

    2014-01-01

    Aim of the performed clinical study was to compare the accuracy and cost-effectiveness of PET/CT in the staging of non-small cell lung cancer (NSCLC). Material and Methods. Cross-sectional and prospective study including 103 patients with histologically confirmed NSCLC. All patients were examined using PET/CT with intravenous contrast medium. Those with disease stage ≤IIB underwent surgery (n = 40). Disease stage was confirmed based on histology results, which were compared with those of PET/CT and positron emission tomography (PET) and computed tomography (CT) separately. 63 patients classified with ≥IIIA disease stage by PET/CT did not undergo surgery. The cost-effectiveness of PET/CT for disease classification was examined using a decision tree analysis. Results. Compared with histology, the accuracy of PET/CT for disease staging has a positive predictive value of 80%, a negative predictive value of 95%, a sensitivity of 94%, and a specificity of 82%. For PET alone, these values are 53%, 66%, 60%, and 50%, whereas for CT alone they are 68%, 86%, 76%, and 72%, respectively. Incremental cost-effectiveness of PET/CT over CT alone was €17,412 quality-adjusted life-year (QALY). Conclusion. In our clinical study, PET/CT using intravenous contrast medium was an accurate and cost-effective method for staging of patients with NSCLC

  19. 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Accuracy in the Staging of Non-Small Cell Lung Cancer: Review and Cost-Effectiveness

    International Nuclear Information System (INIS)

    Leon, N.G.; Bandrs, B.; Escalona, S.; Callejo, D.; Blasco, J.A.; Belda, C.; Blasco, J.A.

    2014-01-01

    Aim of the performed clinical study was to compare the accuracy and cost-effectiveness of PET/CT in the staging of non-small cell lung cancer (NSCLC). Material and Methods. Cross-sectional and prospective study including 103 patients with histologically confirmed NSCLC. All patients were examined using PET/CT with intravenous contrast medium. Those with disease stage ≤IIB underwent surgery (η=40). Disease stage was confirmed based on histology results, which were compared with those of PET/CT and positron emission tomography (PET) and computed tomography (CT) separately. 63 patients classified with ≥IIIA disease stage by PET/CT did not undergo surgery. The cost-effectiveness of PET/CT for disease classification was examined using a decision tree analysis. Results. Compared with histology, the accuracy of PET/CT for disease staging has a positive predictive value of 80%, a negative predictive value of 95%, a sensitivity of 94%, and a specificity of 82%. For PET alone, these values are 53%, 66%, 60%, and 50%, whereas for CT alone they are 68%, 86%, 76%, and 72%, respectively. Incremental cost-effectiveness of PET/CT over CT alone was €17,412 quality-adjusted life-year (QALY). Conclusion. In our clinical study, PET/CT using intravenous contrast medium was an accurate and cost-effective method for staging of patients with NSCLC

  20. Quantification in single photon emission computed tomography (SPECT)

    International Nuclear Information System (INIS)

    Buvat, Irene

    2005-01-01

    The objective of this lecture is to understand the possibilities and limitations of the quantitative analysis of single photon emission computed tomography (SPECT) images. It is also to identify the conditions to be fulfilled to obtain reliable quantitative measurements from images. Content: 1 - Introduction: Quantification in emission tomography - definition and challenges; quantification biasing phenomena; 2 - quantification in SPECT, problems and correction methods: Attenuation, scattering, un-stationary spatial resolution, partial volume effect, movement, tomographic reconstruction, calibration; 3 - Synthesis: actual quantification accuracy; 4 - Beyond the activity concentration measurement

  1. Effective Practices for Online Delivery of Quantitative Business Courses

    Science.gov (United States)

    Lam, Helen; Khare, Anshuman

    2010-01-01

    Online delivery of university-level courses has grown exponentially in the last decade and is increasingly being recognised as a viable and effective alternative to face-to-face classroom teaching. Many scholars have already written about the benefits and best practices of online teaching in general. However, not many studies have paid specific…

  2. Science curriculum effects in high school: A quantitative synthesis

    Science.gov (United States)

    Weinstein, Thomas; Boulanger, F. David; Walberg, Herbert J.

    To assess the impact of the innovative precollege science curricula of the past twenty years on learning, a search was conducted using the computer-assisted Bibliographic Retrieval System (BRS), the ERIC Annual Summaries of Research in Science Education, and Dissertation Abstracts International. A total of 151 effect sizes were obtained from 33 studies representing 19,149 junior and senior high school students in the United States, Great Britain, and Israel. Study-weighted analysis yielded an overall mean effect size of 0.31 significantly favorable to the innovative curricula [t(25) = 2.183, p < 0.05] on all outcomes. Student performance in innovative curricula averaged in the 62nd percentile relative to the control norm. Tabulation of signed comparisons indicated that sixty-four out of eighty-one unweighted outcomes were favorable to the innovative curricula. Separate analyses for test content bias, methodological rigor, type of learning, and student characteristics showed no significant differences across these categories.

  3. Evaluation of outcome prediction and disease extension by quantitative 2-deoxy-2-[18F] fluoro-D-glucose with positron emission tomography in patients with small cell lung cancer

    International Nuclear Information System (INIS)

    Arslan, N.; Tuncel, M.; Kuzhan, O.; Alagoz, E.; Budakoglu, B.; Ozet, A.; Ozguven, M.A.

    2011-01-01

    The objective of this study is to determine whether 2-deoxy-2-[18F] fluoro-D-glucose with positron emission tomography (FDG-PET) imaging and quantitative PET parameters can predict outcome and differentiate patients with limited disease (LD) from extensive disease (ED) in patients with small cell lung cancer (SCLC). We retrospectively evaluated data from 25 patients who underwent either initial staging (Group A, n 12) or restaging (Group B, n 13) by conventional imaging methods and FDG-PET according to the simplified staging scheme developed by the Veterans Administration Lung Cancer Study Group-2. FDG-PET images were both visually and quantitatively evaluated with standardized uptake value (SUV) max , SUV ave , total metabolic tumor volume (with SUV max >%50 and SUV max >2.5), total lesion glycolysis (TLG) (with SUV max >%50 and SUV max >2.5). The correlation between quantitative PET parameters, disease stages and survival were analyzed. By conventional methods 14 of 25 (56%) patients were reported to have LD and 11 of 25 (44%) had ED. FDG-PET scan upstaged 9 out of 25 (36%) and downstaged 2 out of 25 (%8) patients. Among the quantitative PET parameters, TLGs were the only PET parameters that differentiated between Group A and Group B patients. FDG-PET staging (p=0.019) could predict significant survival difference between stages on contrary to conventional staging (p=0.055). Moreover, TLG [SUV max >%50] was the only quantitative PET parameter that could predict survival (p=0.027). FDG-PET imaging is a valuable tool in the management of patients with SCLC for a more accurate staging. The use of quantitative PET parameters may have a role in prediction of stage and survival. (author)

  4. An incommensurately modulated structure of eta '-phase of Cu.sub.3+x./sub.Si determined by quantitative electron diffraction tomography

    Czech Academy of Sciences Publication Activity Database

    Palatinus, Lukáš; Klementová, Mariana; Dřínek, Vladislav; Jarošová, Markéta; Petříček, Václav

    2011-01-01

    Roč. 50, č. 8 (2011), s. 3743-3751 ISSN 0020-1669 R&D Projects: GA ČR GA203/09/1088 Institutional research plan: CEZ:AV0Z10100521; CEZ:AV0Z40720504 Keywords : copper silicide * incommensurate structure * electron diffraction tomography * ab inition structure solution * superspace Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.601, year: 2011

  5. Influence of multi-hit capability on quantitative measurement of NiPtSi thin film with laser-assisted atom probe tomography

    International Nuclear Information System (INIS)

    Kinno, T.; Akutsu, H.; Tomita, M.; Kawanaka, S.; Sonehara, T.; Hokazono, A.; Renaud, L.; Martin, I.; Benbalagh, R.; Sallé, B.; Takeno, S.

    2012-01-01

    Highlights: ► Laser-assisted atom probe tomography was applied to NiPtSi films on Si substrates. ► Comparison of depth profiles of single-hit events and those of multi-hit events. ► ∼80% of Pt atoms were detected in multi-hit events. ► Multiple-ion detection is important for Laser-assisted atom probe tomography. - Abstract: Laser-assisted atom probe tomography (LA-APT) was applied to NiPtSi (0, 30, and 50% Pt contents) thin films on Si substrates. Consistent results with those of high-resolution Rutherford backscattering spectrometry (HR-RBS) were obtained. Based on the obtained data sets, the composition profiles from only the signals of single-hit events, meaning detection of one ion by one laser pulse, were compiled. The profiles from only the signals of multi-hit events, meaning detection of multiple ions by one laser pulse, were also compiled. There were large discrepancies with respect to Ni and Pt concentrations among the compiled profiles and the original profiles including the signals of both types of detection events. Additionally, the profiles compiled from single-hit events showed that Si concentration in NiPtSi layer became smaller toward the surface, differing from the original profiles and the multi-hit profiles. These results suggest that capability of simultaneous multiple-ion detection is important for appropriate LA-APT analyses.

  6. Regional Diagnostic Reference Levels and Collective Effective Doses from Computed Tomography (CT) Scanners in India

    International Nuclear Information System (INIS)

    Livingstone, R.S.; Dinakaran, P.M.

    2011-01-01

    Diagnostic examinations performed using computed tomography (CT) are on the increase, and the use of this modality needs to be monitored periodically. The aim of this study was to formulate regional diagnostic reference levels (DRLs) and assess collective effective doses from CT scanners in Tamil Nadu, India. In-site CT dose measurements were performed for 127 CT scanners in Tamil Nadu as a part of the Atomic Energy Regulatory Board (AERB) funded project for a period of two years. Regional DRLs were formulated at third quartile level for three CT protocols such as thorax, abdomen and pelvis and were found to be 557 mGy.cm, 521 mGy.cm and 294 mGy.cm, respectively. The collective effective dose in Tamil Nadu was found to be 14.93 man Sv per day. (author)

  7. Quantitative microwave impedance microscopy with effective medium approximations

    Directory of Open Access Journals (Sweden)

    T. S. Jones

    2017-02-01

    Full Text Available Microwave impedance microscopy (MIM is a scanning probe technique to measure local changes in tip-sample admittance. The imaginary part of the reported change is calibrated with finite element simulations and physical measurements of a standard capacitive sample, and thereafter the output ΔY is given a reference value in siemens. Simulations also provide a means of extracting sample conductivity and permittivity from admittance, a procedure verified by comparing the estimated permittivity of polytetrafluoroethlyene (PTFE to the accepted value. Simulations published by others have investigated the tip-sample system for permittivity at a given conductivity, or conversely conductivity and a given permittivity; here we supply the full behavior for multiple values of both parameters. Finally, the well-known effective medium approximation of Bruggeman is considered as a means of estimating the volume fractions of the constituents in inhomogeneous two-phase systems. Specifically, we consider the estimation of porosity in carbide-derived carbon, a nanostructured material known for its use in energy storage devices.

  8. Quantitative and economical assessment of effectiveness of electrostatic pesticide spraying

    International Nuclear Information System (INIS)

    Nishimura, Ryo; Fujita, Satoko; Michihara, Shota; Masuoka, Takashi; Kimura, Toshihiro; Yatsuzuka, Shinji; Anaguchi, Shinobu

    2013-01-01

    Electrostatic pesticide spraying (EPS) improves the adhesion characteristics of the pesticide solution to agricultural crops. If the adhesion characteristics are improved, the requisite amount of the pesticide to be sprayed can be reduced in comparison with the conventional spraying method that uses non-charged pesticide. In this research, disease (rust) control experiments were carried out to substantiate the effectiveness of the EPS from a statistical point of view. We sprayed pesticide to potted Japanese pear trees under calm condition. The numbers of the rust lesions on the pear leaves were counted at fixed intervals after spraying to investigate the difference of the results of the disease control. The t-tests were carried out for the populations of the various spraying times and applied voltages. It was statistically-derived that EPS can reduce the amounts of pesticide to be sprayed by 50 % in comparison with the non-EPS method. It is also estimated from the results that about 55,000 kL year −1 of pesticides can be reduced for the Japanese pear cultivation in Tottori prefecture. Also, this means that the expense of the pear cultivation can be reduced by about 240 million yen (3 million USD) every year in Tottori prefecture by introducing EPS.

  9. Semi-quantitative and simulation analyses of effects of {gamma} rays on determination of calibration factors of PET scanners with point-like {sup 22}Na sources

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Tomoyuki [School of Allied Health Sciences, Kitasato University, 1-15-1, Kitasato, Minamiku, Sagamihara, Kanagawa, 252-0373 (Japan); Sato, Yasushi [National Institute of Advanced Industrial Science and Technology, 1-1-1, Umezono, Tsukuba, Ibaraki, 305-8568 (Japan); Oda, Keiichi [Tokyo Metropolitan Institute of Gerontology, 1-1, Nakamachi, Itabashi, Tokyo, 173-0022 (Japan); Wada, Yasuhiro [RIKEN Center for Molecular Imaging Science, 6-7-3, Minamimachi, Minatoshima, Chuo, Kobe, Hyogo, 650-0047 (Japan); Murayama, Hideo [National Institute of Radiological Sciences, 4-9-1, Anagawa, Inage, Chiba, 263-8555 (Japan); Yamada, Takahiro, E-mail: hasegawa@kitasato-u.ac.jp [Japan Radioisotope Association, 2-28-45, Komagome, Bunkyo-ku, Tokyo, 113-8941 (Japan)

    2011-09-21

    The uncertainty of radioactivity concentrations measured with positron emission tomography (PET) scanners ultimately depends on the uncertainty of the calibration factors. A new practical calibration scheme using point-like {sup 22}Na radioactive sources has been developed. The purpose of this study is to theoretically investigate the effects of the associated 1.275 MeV {gamma} rays on the calibration factors. The physical processes affecting the coincidence data were categorized in order to derive approximate semi-quantitative formulae. Assuming the design parameters of some typical commercial PET scanners, the effects of the {gamma} rays as relative deviations in the calibration factors were evaluated by semi-quantitative formulae and a Monte Carlo simulation. The relative deviations in the calibration factors were less than 4%, depending on the details of the PET scanners. The event losses due to rejecting multiple coincidence events of scattered {gamma} rays had the strongest effect. The results from the semi-quantitative formulae and the Monte Carlo simulation were consistent and were useful in understanding the underlying mechanisms. The deviations are considered small enough to correct on the basis of precise Monte Carlo simulation. This study thus offers an important theoretical basis for the validity of the calibration method using point-like {sup 22}Na radioactive sources.

  10. Effects of spacer orientations on the cake formation during membrane fouling: Quantitative analysis based on 3D OCT imaging.

    Science.gov (United States)

    Liu, Xin; Li, Weiyi; Chong, Tzyy Haur; Fane, Anthony G

    2017-03-01

    Spacer design plays an important role in improving the performance of membrane processes for water/wastewater treatment. This work focused on a fundamental issue of spacer design, i.e., investigating the effects of spacer orientations on the fouling behavior during a membrane process. A series of fouling experiments with different spacer orientation were carried out to in situ characterize the formation of a cake layer in a spacer unit cell via 3D optical coherence tomography (OCT) imaging. The cake layers formed at different times were digitalized for quantitatively analyzing the variation in the cake morphology as a function of time. In particular, the local deposition rates were evaluated to determine the active regions where the instantaneous changes in deposit thickness were significant. The characterization results indicate that varying the spacer orientation could substantially change the evolution of membrane fouling by particulate foulants and thereby result in a cake layer with various morphologies; the competition between growth and erosion at different locations would instantaneously respond to the micro-hydrodynamic environment that might change with time. This work confirms that the OCT-based characterization method is a powerful tool for exploring novel spacer design. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Positron Emission Tomography : background, possibilities and perspectives in neuroscience

    NARCIS (Netherlands)

    Paans, AMJ

    Positron Emission Tomography (PET) is a method for determining biochemical and physiological processes in vivo in a quantitative way. This includes the measurement of the pharmacokinetics of labeled drugs and the measurement of the effects of drugs and/or therapy on metabolism. Also deviations of

  12. High-pitch spiral computed tomography: effect on image quality and radiation dose in pediatric chest computed tomography.

    Science.gov (United States)

    Lell, Michael M; May, Matthias; Deak, Paul; Alibek, Sedat; Kuefner, Michael; Kuettner, Axel; Köhler, Henrik; Achenbach, Stephan; Uder, Michael; Radkow, Tanja

    2011-02-01

    computed tomography (CT) is considered the method of choice in thoracic imaging for a variety of indications. Sedation is usually necessary to enable CT and to avoid deterioration of image quality because of patient movement in small children. We evaluated a new, subsecond high-pitch scan mode (HPM), which obviates the need of sedation and to hold the breath. a total of 60 patients were included in this study. 30 patients (mean age, 14 ± 17 month; range, 0-55 month) were examined with a dual source CT system in an HPM. Scan parameters were as follows: pitch = 3.0, 128 × 0.6 mm slice acquisition, 0.28 seconds gantry rotation time, ref. mAs adapted to the body weight (50-100 mAs) at 80 kV. Images were reconstructed with a slice thickness of 0.75 mm. None of the children was sedated for the CT examination and no breathing instructions were given. Image quality was assessed focusing on motion artifacts and delineation of the vascular structures and lung parenchyma. Thirty patients (mean age, 15 ± 17 month; range, 0-55 month) were examined under sedation on 2 different CT systems (10-slice CT, n = 18; 64-slice CT, n = 13 patients) in conventional pitch mode (CPM). Dose values were calculated from the dose length product provided in the patient protocol/dose reports, Monte Carlo simulations were performed to assess dose distribution for CPM and HPM. all scans were performed without complications. Image quality was superior with HPM, because of a significant reduction in motion artifacts, as compared to CPM with 10- and 64-slice CT. In the control group, artifacts were encountered at the level of the diaphragm (n = 30; 100%), the borders of the heart (n = 30; 100%), and the ribs (n = 20; 67%) and spine (n = 6; 20%), whereas motion artifacts were detected in the HPM-group only in 6 patients in the lung parenchyma next to the diaphragm or the heart (P detector width and pitch-value. high-pitch chest CT is a robust method to provide highest image quality making sedation

  13. Quantitative and qualitative analysis of [{sup 18}F]FDG and [{sup 18}F]FAZA positron emission tomography of head and neck cancers and associations with HPV status and treatment outcome

    Energy Technology Data Exchange (ETDEWEB)

    Graves, Edward E.; Le, Quynh-Thu [Stanford University, Department of Radiation Oncology, Stanford, CA (United States); Hicks, Rodney J.; Binns, David; Peters, Lester [Peter MacCallum Cancer Centre, Division of Radiation Oncology and Cancer Imaging, Melbourne (Australia); Bressel, Mathias; Young, Richard J. [Peter MacCallum Cancer Centre, Division of Research, Melbourne (Australia); Rischin, Danny [Peter MacCallum Cancer Centre, Division of Cancer Medicine, Melbourne (Australia)

    2016-04-15

    While methods for imaging tumor hypoxia with positron emission tomography (PET) have been developed, optimal methods for interpreting and utilizing these datasets in the clinic remain unclear. In this study, we analyzed hypoxia PET images of head and neck cancer patients and compared imaging metrics with human papilloma virus (HPV) status and clinical outcome. Forty-one patients treated as part of a phase III trial of the hypoxic cytotoxin tirapazamine (TROG 02.02) were imaged with PET using fluorodeoxyglucose (FDG) and fluoroazomycin arabinoside (FAZA). FDG and FAZA PET images were interpreted qualitatively and quantitatively, and compared with tumor T stage, HPV status, and treatment outcome using multivariate statistics. PET signals in the tumor and lymph nodes exhibited significant intra- and inter-patient variability. The FAZA hypoxic volume demonstrated a significant correlation with tumor T stage. PET-hypoxic tumors treated with cisplatin exhibited significantly worse treatment outcomes relative to PET-oxic tumors or PET-hypoxic tumors treated with tirapazamine. Quantitative analysis of FAZA PET yielded metrics that correlated with clinical T stage and were capable of stratifying patient outcome. These results encourage further development of this technology, with particular emphasis on establishment of robust quantitative methods. (orig.)

  14. Quantitative and qualitative analysis of [18F]FDG and [18F]FAZA positron emission tomography of head and neck cancers and associations with HPV status and treatment outcome

    International Nuclear Information System (INIS)

    Graves, Edward E.; Le, Quynh-Thu; Hicks, Rodney J.; Binns, David; Peters, Lester; Bressel, Mathias; Young, Richard J.; Rischin, Danny

    2016-01-01

    While methods for imaging tumor hypoxia with positron emission tomography (PET) have been developed, optimal methods for interpreting and utilizing these datasets in the clinic remain unclear. In this study, we analyzed hypoxia PET images of head and neck cancer patients and compared imaging metrics with human papilloma virus (HPV) status and clinical outcome. Forty-one patients treated as part of a phase III trial of the hypoxic cytotoxin tirapazamine (TROG 02.02) were imaged with PET using fluorodeoxyglucose (FDG) and fluoroazomycin arabinoside (FAZA). FDG and FAZA PET images were interpreted qualitatively and quantitatively, and compared with tumor T stage, HPV status, and treatment outcome using multivariate statistics. PET signals in the tumor and lymph nodes exhibited significant intra- and inter-patient variability. The FAZA hypoxic volume demonstrated a significant correlation with tumor T stage. PET-hypoxic tumors treated with cisplatin exhibited significantly worse treatment outcomes relative to PET-oxic tumors or PET-hypoxic tumors treated with tirapazamine. Quantitative analysis of FAZA PET yielded metrics that correlated with clinical T stage and were capable of stratifying patient outcome. These results encourage further development of this technology, with particular emphasis on establishment of robust quantitative methods. (orig.)

  15. Effects of computer tomography on diagnosis of neurological and neurosurgical diseases

    International Nuclear Information System (INIS)

    Katzner, E.

    1981-01-01

    Computer tomography is presently the primary procedure for correct diagnosis of many neurological and neurosurgical diseases. Other expensive and riskier diagnostic methods have become superfluous. Selective and clearly indicated application of the undoubtedly expensive computer tomography ultimately spares unnecessary costs for hospitalization and less conclusive examination methods. Wheras the indications in the craniocerebral region can now be considered confirmed, spinal computer tomography is still in the development stage. With certain indications, e.g. in prolapsed lumbar intervertebral disk, a similar performance to that of CT can be obtained with myelography, so that the latter method is likely to be superceded by computer tomography. (orig.) [de

  16. Extending the Effective Ranging Depth of Spectral Domain Optical Coherence Tomography by Spatial Frequency Domain Multiplexing

    Directory of Open Access Journals (Sweden)

    Tong Wu

    2016-11-01

    Full Text Available We present a spatial frequency domain multiplexing method for extending the imaging depth range of a spectral domain optical coherence tomography (SDOCT system without any expensive device. This method uses two galvo scanners with different pivot-offset distances in two independent reference arms for spatial frequency modulation and multiplexing. The spatial frequency contents corresponding to different depth regions of the sample can be shifted to different frequency bands. The spatial frequency domain multiplexing SDOCT system provides an approximately 1.9-fold increase in the effective ranging depth compared with that of a conventional full-range SDOCT system. The reconstructed images of phantom and biological tissue demonstrate the expected increase in ranging depth. The parameters choice criterion for this method is discussed.

  17. Evaluation of effective regurgitant orifice area of mitral valvular regurgitation by multislice cardiac computed tomography

    International Nuclear Information System (INIS)

    Vural, M.; Ucar, O.; Celebi, O.O.; Cicekcioglu, H.; Durmaz, H.A.; Selvi, N.A.; Koparal, S.; Aydogdu, S.

    2010-01-01

    The purpose of our study was to assess the diagnostic accuracy of multislice computed tomography (MSCT) for the identification and quantification of mitral valve regurgitation in comparison with transthoracic echocardiography (TTE). Twenty-six patients (15 females, 11 males with a mean age of 44.6±14.1 years) who were in follow-up with the diagnosis of mitral regurgitation and those who were referred for MSCT were enrolled. MSCT results were compared with TTE measurements. The mean effective mitral regurgitant orifice area at MSCT was 23.1±13.0 mm 2 and at echocardiography was 24.4±16.0mm 2 . Bland-Altman analysis showed good agreement between the two imaging methods. MSCT provides reliable and good results for the evaluation of mitral regurgitation. (author)

  18. Effect of field-of-view size on gray values derived from cone-beam computed tomography compared with the Hounsfield unit values from multidetector computed tomography scans.

    Science.gov (United States)

    Shokri, Abbas; Ramezani, Leila; Bidgoli, Mohsen; Akbarzadeh, Mahdi; Ghazikhanlu-Sani, Karim; Fallahi-Sichani, Hamed

    2018-03-01

    This study aimed to evaluate the effect of field-of-view (FOV) size on the gray values derived from conebeam computed tomography (CBCT) compared with the Hounsfield unit values from multidetector computed tomography (MDCT) scans as the gold standard. A radiographic phantom was designed with 4 acrylic cylinders. One cylinder was filled with distilled water, and the other 3 were filled with 3 types of bone substitute: namely, Nanobone, Cenobone, and Cerabone. The phantom was scanned with 2 CBCT systems using 2 different FOV sizes, and 1 MDCT system was used as the gold standard. The mean gray values (MGVs) of each cylinder were calculated in each imaging protocol. In both CBCT systems, significant differences were noted in the MGVs of all materials between the 2 FOV sizes ( P <.05) except for Cerabone in the Cranex3D system. Significant differences were found in the MGVs of each material compared with the others in both FOV sizes for each CBCT system. No significant difference was seen between the Cranex3D CBCT system and the MDCT system in the MGVs of bone substitutes on images obtained with a small FOV. The size of the FOV significantly changed the MGVs of all bone substitutes, except for Cerabone in the Cranex3D system. Both CBCT systems had the ability to distinguish the 3 types of bone substitutes based on a comparison of their MGVs. The Cranex3D CBCT system used with a small FOV had a significant correlation with MDCT results.

  19. 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.

  20. Reducing the effects of acoustic heterogeneity with an iterative reconstruction method from experimental data in microwave induced thermoacoustic tomography

    International Nuclear Information System (INIS)

    Wang, Jinguo; Zhao, Zhiqin; Song, Jian; Chen, Guoping; Nie, Zaiping; Liu, Qing-Huo

    2015-01-01

    Purpose: An iterative reconstruction method has been previously reported by the authors of this paper. However, the iterative reconstruction method was demonstrated by solely using the numerical simulations. It is essential to apply the iterative reconstruction method to practice conditions. The objective of this work is to validate the capability of the iterative reconstruction method for reducing the effects of acoustic heterogeneity with the experimental data in microwave induced thermoacoustic tomography. Methods: Most existing reconstruction methods need to combine the ultrasonic measurement technology to quantitatively measure the velocity distribution of heterogeneity, which increases the system complexity. Different to existing reconstruction methods, the iterative reconstruction method combines time reversal mirror technique, fast marching method, and simultaneous algebraic reconstruction technique to iteratively estimate the velocity distribution of heterogeneous tissue by solely using the measured data. Then, the estimated velocity distribution is used subsequently to reconstruct the highly accurate image of microwave absorption distribution. Experiments that a target placed in an acoustic heterogeneous environment are performed to validate the iterative reconstruction method. Results: By using the estimated velocity distribution, the target in an acoustic heterogeneous environment can be reconstructed with better shape and higher image contrast than targets that are reconstructed with a homogeneous velocity distribution. Conclusions: The distortions caused by the acoustic heterogeneity can be efficiently corrected by utilizing the velocity distribution estimated by the iterative reconstruction method. The advantage of the iterative reconstruction method over the existing correction methods is that it is successful in improving the quality of the image of microwave absorption distribution without increasing the system complexity

  1. How does nose blowing effect the computed tomography of paranasal sinuses in chronic sinusitis?

    Energy Technology Data Exchange (ETDEWEB)

    Savranlar, Ahmet; Uzun, Lokman; Ugur, Mehmet Birol; Mahmutyazicioglu, Kamran; Ozer, Tulay; Gundogdu, Sadi

    2005-02-01

    Objective: Our aim was to determine whether inward or outward movement of the secretions in the paranasal sinuses due to nose blowing after nasal decongestion has any effect on the paranasal sinus computed tomography (CT) images in patients with sinusitis and to asses whether nose blowing may result in misdiagnosis or overdiagnosis in radiological evaluation of sinusitis. Materials and methods: Twenty-four patients with chronic sinusitis were evaluated in an academic tertiary care hospital and data were collected prospectively. After coronal sinus computed tomography scans were performed at 100 mA setting which was half the value of the standard radiation dose suggested by the manufacturer, topical decongestion was applied to each nostril followed by nose blowing 10 min later. Sinus CT scans were then repeated at the same setting. We evaluated the mucosal thickness of medial, lateral, superior and inferior maxillary and frontal sinus walls and the maximal thickness in anterior ethmoidal cells. The measurements prior to and following nose blowing were compared with Wilcoxon signed ranks test. The obtained images were also staged using Lund-McKay staging system separately and the scores were compared with Student's t-test. Results: We observed a tendency towards reduction in mucosal thickness after nose blowing. There were statistically significant differences between maxillary sinus inferior wall and frontal sinus inferior wall mucosal thickness values prior to and after nose blowing. The difference however was very small, about 0.5 mm in magnitude and Lund-McKay score did not change in any of the patients after nose blowing. Conclusion: Nose blowing and topical nasal decongestion does not have any effect on the diagnostic accuracy of sinus CT in chronic sinusitis patients.

  2. How does nose blowing effect the computed tomography of paranasal sinuses in chronic sinusitis?

    International Nuclear Information System (INIS)

    Savranlar, Ahmet; Uzun, Lokman; Ugur, Mehmet Birol; Mahmutyazicioglu, Kamran; Ozer, Tulay; Gundogdu, Sadi

    2005-01-01

    Objective: Our aim was to determine whether inward or outward movement of the secretions in the paranasal sinuses due to nose blowing after nasal decongestion has any effect on the paranasal sinus computed tomography (CT) images in patients with sinusitis and to asses whether nose blowing may result in misdiagnosis or overdiagnosis in radiological evaluation of sinusitis. Materials and methods: Twenty-four patients with chronic sinusitis were evaluated in an academic tertiary care hospital and data were collected prospectively. After coronal sinus computed tomography scans were performed at 100 mA setting which was half the value of the standard radiation dose suggested by the manufacturer, topical decongestion was applied to each nostril followed by nose blowing 10 min later. Sinus CT scans were then repeated at the same setting. We evaluated the mucosal thickness of medial, lateral, superior and inferior maxillary and frontal sinus walls and the maximal thickness in anterior ethmoidal cells. The measurements prior to and following nose blowing were compared with Wilcoxon signed ranks test. The obtained images were also staged using Lund-McKay staging system separately and the scores were compared with Student's t-test. Results: We observed a tendency towards reduction in mucosal thickness after nose blowing. There were statistically significant differences between maxillary sinus inferior wall and frontal sinus inferior wall mucosal thickness values prior to and after nose blowing. The difference however was very small, about 0.5 mm in magnitude and Lund-McKay score did not change in any of the patients after nose blowing. Conclusion: Nose blowing and topical nasal decongestion does not have any effect on the diagnostic accuracy of sinus CT in chronic sinusitis patients

  3. Cardiac positron emission tomography

    International Nuclear Information System (INIS)

    Eftekhari, M.; Ejmalian, G.

    2003-01-01

    Positron emission tomography is an intrinsically tool that provide a unique and unparalleled approach for clinicians and researchers to interrogate the heart noninvasively. The ability to label substances of physiological interest with positron-emitting radioisotopes has permitted insight into normal blood flow and metabolism and the alterations that occur with disease states. Positron emission tomography of the heart has evolved as a unique, noninvasive approach for the assessment of myocardial perfusion, metabolism, and function. Because of the intrinsic quantitative nature of positron emission tomography measurements as well as the diverse compounds that can be labeled with positron- emitting radioisotopes, studies with positron emission tomography have provided rich insight into the physiology of the heart under diverse conditions

  4. Positron emission tomography

    NARCIS (Netherlands)

    Paans, AMJ

    Positron Emission Tomography (PET) is a method for determining biochemical and physiological processes in vivo in a quantitative way by using radiopharmaceuticals labelled with positron emitting radionuclides as C-11, N-13, O-15 and F-18 and by measuring the annihilation radiation using a

  5. A Delphi study to establish national cost-effectiveness research priorities for positron emission tomography

    International Nuclear Information System (INIS)

    Robert, Glenn; Milne, Ruairidh

    1999-01-01

    Objective: This study aimed to determine the key cost-effectiveness research questions relating to positron emission tomography (PET) in the UK. Methods: A systematic literature review was conducted to establish the existing knowledge base relating to the cost-effectiveness of PET in the various conditions for which it has been proposed. A three-round postal Delphi study of relevant individuals was used to determine the key cost-effectiveness research questions relating to PET in the UK. The content and structure of the Delphi study was informed by the results of the literature review. Results: The most important cost-effectiveness research priorities for the National Health Service (NHS) relating to PET were in the clinical areas of lung cancer, breast cancer and the assessment of myocardial viability. Gamma camera PET using coincidence imaging was highlighted as a modality whose clinical role needed to be determined urgently. Conclusion: Underlying the cost-effectiveness research priorities which were established is the need for evidence that the use of the various PET modalities as a diagnostic technique will alter patient management as compared to existing diagnostic strategies. The findings of the project provide a contemporary overview of the potential role for PET in the NHS and will be relevant to other countries

  6. The effect of repeated freeze-thaw cycles on human muscle tissue visualized by postmortem computed tomography (PMCT)

    NARCIS (Netherlands)

    Klop, Anthony C.; Vester, Marloes E. M.; Colman, Kerri L.; Ruijter, Jan M.; van Rijn, Rick R.; Oostra, Roelof-Jan

    2017-01-01

    The aim of this study was to determine whether effects of repetitive freeze-thaw cycles, with various thawing temperatures, on human muscle tissue can be quantified using postmortem computed tomography (PMCT) technology. An additional objective was to determine the preferred thawing temperature for

  7. Single photon emission tomography

    International Nuclear Information System (INIS)

    Buvat, Irene

    2011-09-01

    The objective of this lecture is to present the single photon emission computed tomography (SPECT) imaging technique. Content: 1 - Introduction: anatomic, functional and molecular imaging; Principle and role of functional or molecular imaging; 2 - Radiotracers: chemical and physical constraints, main emitters, radioisotopes production, emitters type and imaging techniques; 3 - Single photon emission computed tomography: gamma cameras and their components, gamma camera specifications, planar single photon imaging characteristics, gamma camera and tomography; 4 - Quantification in single photon emission tomography: attenuation, scattering, un-stationary spatial resolution, partial volume effect, movements, others; 5 - Synthesis and conclusion

  8. Use of Monte Carlo simulation software for calculating effective dose in cone beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Gomes B, W. O., E-mail: wilsonottobatista@gmail.com [Instituto Federal da Bahia, Rua Emidio dos Santos s/n, Barbalho 40301-015, Salvador de Bahia (Brazil)

    2016-10-15

    This study aimed to develop a geometry of irradiation applicable to the software PCXMC and the consequent calculation of effective dose in applications of the Computed Tomography Cone Beam (CBCT). We evaluated two different CBCT equipment s for dental applications: Care stream Cs 9000 3-dimensional tomograph; i-CAT and GENDEX GXCB-500. Initially characterize each protocol measuring the surface kerma input and the product kerma air-area, P{sub KA}, with solid state detectors RADCAL and PTW transmission chamber. Then we introduce the technical parameters of each preset protocols and geometric conditions in the PCXMC software to obtain the values of effective dose. The calculated effective dose is within the range of 9.0 to 15.7 μSv for 3-dimensional computer 9000 Cs; within the range 44.5 to 89 μSv for GXCB-500 equipment and in the range of 62-111 μSv for equipment Classical i-CAT. These values were compared with results obtained dosimetry using TLD implanted in anthropomorphic phantom and are considered consistent. Os effective dose results are very sensitive to the geometry of radiation (beam position in mathematical phantom). This factor translates to a factor of fragility software usage. But it is very useful to get quick answers to regarding process optimization tool conclusions protocols. We conclude that use software PCXMC Monte Carlo simulation is useful assessment protocols for CBCT tests in dental applications. (Author)

  9. A Quantitative Analytical Method to Test for Salt Effects on Giant Unilamellar Vesicles

    DEFF Research Database (Denmark)

    Hadorn, Maik; Bönzli, Eva; Eggenberger Hotz, Peter

    2011-01-01

    preparation method with automatic haemocytometry. We found that this new quantitative screening method is highly reliable and consistent with previously reported results. Thus, this method may provide a significant methodological advance in analysis of effects on free-standing model membranes....

  10. A Quantitative Analysis of the Effect of Simulation on Medication Administration in Nursing Students

    Science.gov (United States)

    Scudmore, Casey

    2013-01-01

    Medication errors are a leading cause of injury and death in health care, and nurses are the last line of defense for patient safety. Nursing educators must develop curriculum to effectively teach nursing students to prevent medication errors and protect the public. The purpose of this quantitative, quasi-experimental study was to determine if…

  11. The Quantitative Effect of Students Using Podcasts in a First Year Undergraduate Exercise Physiology Module

    Science.gov (United States)

    Abt, Grant; Barry, Tim

    2007-01-01

    This study reports the quantitative effect of students using podcasts in a 1st year undergraduate exercise physiology module. From a cohort of 70 students, 50 volunteered and completed the study. Using a pre-post random allocation research design, students were allocated to either a podcast group (PG) or control group (CG) based on a 32-question…

  12. Effect of mandibular plane angle on image dimensions in linear tomography

    Directory of Open Access Journals (Sweden)

    Bashizadeh Fakhar H

    2011-02-01

    Full Text Available "nBackground and Aims: Accurate bone measurements are essential for determining the optimal size and length of proposed implants. The radiologist should be aware of the head position effects on image dimensions in each imaging technique. The purpose of this study was to evaluate the effect of mandibular plane angle on image dimensions in linear tomography."nMaterials and Methods: In this in vitro study, the vertical dimensions of linear tomograms taken from 3 dry mandibles in different posteroantenior or mediolateral tilts were compared with actual condition. In order to evaluate the effects of head position in linear tomography, 16 series of images while mandibular plane angle was tilted with 5, 10, 15 and 20 degrees in anterior, posterior, medial, or lateral angulations as well as a series of standard images without any tilt in mandibular position were taken. Vertical distances between the alveolar crest and the superior border of the inferior alveolar canal were measured in posterior mandible and the vertical distances between the alveolar crest and inferior rim were measured in anterior mandible in 12 sites of tomograms. Each bone was then sectioned through the places marked with a radiopaque object. The radiographic values were compared with the real conditions. Repeat measure ANOVA was used to analyze the data."nResults: The findings of this study showed that there was significant statistical difference between standard position and 15º posteroanterior tilt (P<0.001. Also there was significant statistical difference between standard position and 10º lateral tilt (P<0.008, 15º tilt (P<0.001, and 20º upward tilt (P<0.001. In standard mandibular position with no tilt, the mean exact error was the same in all regions (0.22±0.19 mm except the premolar region which the mean exact error was calculated as 0.44±0.19 mm. The most mean exact error among various postroanterior tilts was seen in 20º lower tilt in the canine region (1±0.88 mm

  13. An introduction to emission computed tomography

    International Nuclear Information System (INIS)

    Williams, E.D.

    1985-01-01

    This report includes salient features of the theory and an examination of practical considerations for someone who is using or introducing tomography, selecting equipment for it or wishing to develop a clinical application. Emphasis is on gamma camera tomography. The subject is dealt with under the following headings: emission computed and gamma camera tomography and the relationship to other medical imaging techniques, the tomographic reconstruction technique theory, rotating gamma camera tomography, attenuation correction and quantitative reconstruction, other single photon tomographic techniques, positron tomography, image display, clinical application of single photon and positron tomography, and commercial systems for SPECT. Substantial bibliography. (U.K.)

  14. A new practical model of testes shield: the effectiveness during abdominopelvic computed tomography.

    Science.gov (United States)

    Sancaktutar, Ahmet Ali; Bozkurt, Yaşar; Önder, Hakan; Söylemez, Haluk; Atar, Murat; Penbegül, Necmettin; Ziypak, Tevfik; Tekbaş, Güven; Tepeler, Abdülkadir

    2012-01-01

    The goal of our prospective study was to measure the effect of a new standard model male gonad shield on the testicular radiation exposure during routine abdominopelvic computed tomography (CT). Two hundred male patients who underwent upper abdominal and pelvic CT examinations were included in our study. To prepare the testes shield (TS), 2 No. 8 fluoroscopy radiation-protection gloves made of bismuth (0.35 mm lead equivalent) were used. These gloves were invaginated into one another and their fingers were turned inside out. Scrotums of all patients were pushed into these lead-containing gloves. Upper abdominal CT (n = 6), pelvic CT (n = 9), and abdominopelvic scanning (n = 185) were performed. Immediately after the CT examinations and at postprocedural day 1, the scrotal examinations were repeated. None of the patients exhibited scrotal laceration, edema, eruption, erythema, tenderness, or pain. During the CT examinations, 22 patients (11%) felt unrest because of their exposed genital regions, without any adverse effect on the procedure. Dosimetric measurements of radioactivity inside the TS (dosimeter I) and outside it (dosimeter II) were 6.8 and 69.00 mSv, respectively. Accordingly, the TS we used in our study reduced the radiation exposure of the testes by 90.2% (10.1 times). We think that the use of this radioprotective TS during radiological diagnostic and therapeutic procedures is an appropriate approach from both a medical and legal perspective. Therefore, we recommend this userfriendly, practical, low-cost, and effective TS for all radiologic procedures.

  15. Quantitative computed tomography measurements to evaluate airway disease in chronic obstructive pulmonary disease: Relationship to physiological measurements, clinical index and visual assessment of airway disease

    International Nuclear Information System (INIS)

    Nambu, Atsushi; Zach, Jordan; Schroeder, Joyce; Jin, Gongyoung; Kim, Song Soo; Kim, Yu-IL; Schnell, Christina; Bowler, Russell; Lynch, David A.

    2016-01-01

    Purpose: To correlate currently available quantitative CT measurements for airway disease with physiological indices and the body-mass index, airflow obstruction, dyspnea, and exercise capacity (BODE) index in patients with chronic obstructive pulmonary disease (COPD). Materials and methods: This study was approved by our institutional review board (IRB number 2778). Written informed consent was obtained from all subjects. The subjects included 188 current and former cigarette smokers from the COPDGene cohort who underwent inspiratory and expiratory CT and also had physiological measurements for the evaluation of airflow limitation, including FEF25-75%, airway resistance (Raw), and specific airway conductance (sGaw). The BODE index was used as the index of clinical symptoms. Quantitative CT measures included % low attenuation areas [% voxels ≤ 950 Hounsfield unit (HU) on inspiratory CT, %LAA −950ins ], percent gas trapping (% voxels ≤ −856 HU on expiratory CT, %LAA −856exp ), relative inspiratory to expiratory volume change of voxels with attenuation values from −856 to −950 HU [Relative Volume Change (RVC) −856 to −950 ], expiratory to inspiratory ratio of mean lung density (E/I-ratio MLD ), Pi10, and airway wall thickness (WT), luminal diameter (LD) and airway wall area percent (WA%) in the segmental, subsegmental and subsubsegmental bronchi on inspiratory CT. Correlation coefficients were calculated between the QCT measurements and physiological measurements in all subjects and in the subjects with mild emphysema (%LAA −950ins <10%). Univariate and multiple variable analysis for the BODE index were also performed. Adjustments were made for age, gender, smoking pack years, FEF25-75%, Raw, and sGaw. Results: Quantitative CT measurements had significant correlations with physiological indices. Among them, E/I-ratio MLD had the strongest correlations with FEF25-75% (r = −0.648, <0.001) and sGaw (r = −0.624, <0.001) while in the subjects with

  16. Relationships between diffusing capacity for carbon monoxide (D{sub L}CO), and quantitative computed tomography measurements and visual assessment for chronic obstructive pulmonary disease

    Energy Technology Data Exchange (ETDEWEB)

    Nambu, Atsushi, E-mail: nambu-a@gray.plala.or.jp [Department of Radiology, National Jewish Health, 1400 Jackson Street, Denver, CO 80206 (United States); Department of Radiology, Teikyo University Mizonokuchi Hospital (Japan); Zach, Jordan, E-mail: ZachJ@NJHealth.org [Department of Radiology, National Jewish Health, 1400 Jackson Street, Denver, CO 80206 (United States); Schroeder, Joyce, E-mail: Joyce.schroeder@stanfordalumni.org [Department of Radiology, National Jewish Health, 1400 Jackson Street, Denver, CO 80206 (United States); Jin, Gong Yong, E-mail: gyjin@chonbuk.ac.kr [Department of Radiology, National Jewish Health, 1400 Jackson Street, Denver, CO 80206 (United States); Department of Radiology, Chonbuk National University Hospital (Korea, Republic of); Kim, Song Soo, E-mail: haneul88@hanmail.net [Department of Radiology, National Jewish Health, 1400 Jackson Street, Denver, CO 80206 (United States); Department of Radiology, Chungnam National Hospital, Chungnam National University School of Medicine (Korea, Republic of); Kim, Yu-IL, E-mail: kyionly@chonnam.ac.kr [Department of Medicine, National Jewish Health, Denver, CO (United States); Department of Internal Medicine, Chonnam National University Hospital, Gwangju (Korea, Republic of); Schnell, Christina, E-mail: SchnellC@NJHealth.org [Department of Medicine, National Jewish Health, Denver, CO (United States); Bowler, Russell, E-mail: BowlerR@NJHealth.org [Division of Pulmonary Medicine, Department of Medicine, National Jewish Health (United States); Lynch, David A., E-mail: LynchD@NJHealth.org [Department of Radiology, National Jewish Health, 1400 Jackson Street, Denver, CO 80206 (United States)

    2015-05-15

    Highlights: • Quantitative CT measurements significantly correlated with D{sub L}CO/V{sub A}. • 15{sup th} percentile HU had the strongest correlation with D{sub L}CO/V{sub A}. • Visual scoring of emphysema had independent significant correlations with D{sub L}CO/V{sub A}. - Abstract: Purpose: To evaluate the relationships between D{sub L}CO, and Quantitative CT (QCT) measurements and visual assessment of pulmonary emphysema and to test the relative roles of visual and quantitative assessment of emphysema. Materials and methods: The subjects included 199 current and former cigarette smokers from the COPDGene cohort who underwent inspiratory and expiratory CT and also had diffusing capacity for carbon monoxide corrected for alveolar volume (D{sub L}CO/V{sub A}). Quantitative CT measurements included % low attenuation areas (%LAA−950ins = voxels ≤−950 Hounsfield unit (HU), % LAA{sub −910ins}, and % LAA{sub −856ins}), mean CT attenuation and 15th percentile HU value on inspiratory CT, and %LAA{sub −856exp} (voxels ≤−856 HU on expiratory CT). The extent of emphysema was visually assessed using a 5-point grading system. Univariate and multiple variable linear regression analyses were employed to evaluate the correlations between D{sub L}CO/V{sub A} and QCT parameters and visual extent of emphysema. Results: The D{sub L}CO/V{sub A} correlated most strongly with 15th percentile HU (R{sup 2} = 0.440, p < 0.001) closely followed by % LAA{sub −950ins} (R{sup 2} = 0.417, p < 0.001) and visual extent of emphysema (R{sup 2} = 0.411, p < 0.001). Multiple variable analysis showed that visual extent of emphysema and 15th percentile HU were independent significant predictors of D{sub L}CO/V{sub A} at an R{sup 2} of 0.599. Conclusions: 15th percentile HU seems the best parameter to represent the respiratory condition of COPD. Visual and Quantitative CT assessment of emphysema provide complementary information to QCT analysis.

  17. Quantitative Analysis of the Effect of Iterative Reconstruction Using a Phantom: Determining the Appropriate Blending Percentage

    Science.gov (United States)

    Kim, Hyun Gi; Lee, Young Han; Choi, Jin-Young; Park, Mi-Suk; Kim, Myeong-Jin; Kim, Ki Whang

    2015-01-01

    Purpose To investigate the optimal blending percentage of adaptive statistical iterative reconstruction (ASIR) in a reduced radiation dose while preserving a degree of image quality and texture that is similar to that of standard-dose computed tomography (CT). Materials and Methods The CT performance phantom was scanned with standard and dose reduction protocols including reduced mAs or kVp. Image quality parameters including noise, spatial, and low-contrast resolution, as well as image texture, were quantitatively evaluated after applying various blending percentages of ASIR. The optimal blending percentage of ASIR that preserved image quality and texture compared to standard dose CT was investigated in each radiation dose reduction protocol. Results As the percentage of ASIR increased, noise and spatial-resolution decreased, whereas low-contrast resolution increased. In the texture analysis, an increasing percentage of ASIR resulted in an increase of angular second moment, inverse difference moment, and correlation and in a decrease of contrast and entropy. The 20% and 40% dose reduction protocols with 20% and 40% ASIR blending, respectively, resulted in an optimal quality of images with preservation of the image texture. Conclusion Blending the 40% ASIR to the 40% reduced tube-current product can maximize radiation dose reduction and preserve adequate image quality and texture. PMID:25510772

  18. Computerized tomography

    International Nuclear Information System (INIS)

    Rubashov, I.B.

    1985-01-01

    Operating principle is described for the devices of computerized tomography used in medicine for diagnosis of brain diseases. Computerized tomography is considered as a part of computerized diagnosis, as a part of information science. It is shown that computerized tomography is a real existed field of investigations in medicine and industrial production

  19. Quantitation of regional cerebral blood flow corrected for partial volume effect using O-15 water and PET: I. Theory, error analysis, and stereologic comparison

    DEFF Research Database (Denmark)

    Lida, H; Law, I; Pakkenberg, B

    2000-01-01

    Limited spatial resolution of positron emission tomography (PET) can cause significant underestimation in the observed regional radioactivity concentration (so-called partial volume effect or PVE) resulting in systematic errors in estimating quantitative physiologic parameters. The authors have...... formulated four mathematical models that describe the dynamic behavior of a freely diffusible tracer (H215O) in a region of interest (ROI) incorporating estimates of regional tissue flow that are independent of PVE. The current study was intended to evaluate the feasibility of these models and to establish...... a methodology to accurately quantify regional cerebral blood flow (CBF) corrected for PVE in cortical gray matter regions. Five monkeys were studied with PET after IV H2(15)O two times (n = 3) or three times (n = 2) in a row. Two ROIs were drawn on structural magnetic resonance imaging (MRI) scans and projected...

  20. The application of positron emission tomography/computed tomography in radiation treatment planning: effect on gross target volume definition and treatment management.

    Science.gov (United States)

    Iğdem, S; Alço, G; Ercan, T; Unalan, B; Kara, B; Geceer, G; Akman, C; Zengin, F O; Atilla, S; Okkan, S

    2010-04-01

    To analyse the effect of the use of molecular imaging on gross target volume (GTV) definition and treatment management. Fifty patients with various solid tumours who underwent positron emission tomography (PET)/computed tomography (CT) simulation for radiotherapy planning from 2006 to 2008 were enrolled in this study. First, F-18 fluorodeoxyglucose (FDG)-PET and CT scans of the treatment site in the treatment position and then a whole body scan were carried out with a dedicated PET/CT scanner and fused thereafter. FDG-avid primary tumour and lymph nodes were included into the GTV. A multidisciplinary team defined the target volume, and contouring was carried out by a radiation oncologist using visual methods. To compare the PET/CT-based volumes with CT-based volumes, contours were drawn on CT-only data with the help of site-specific radiologists who were blind to the PET/CT results after a median time of 7 months. In general, our PET/CT volumes were larger than our CT-based volumes. This difference was significant in patients with head and neck cancers. Major changes (> or =25%) in GTV delineation were observed in 44% of patients. In 16% of cases, PET/CT detected incidental second primaries and metastatic disease, changing the treatment strategy from curative to palliative. Integrating functional imaging with FDG-PET/CT into the radiotherapy planning process resulted in major changes in a significant proportion of our patients. An interdisciplinary approach between imaging and radiation oncology departments is essential in defining the target volumes. Copyright 2010 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  1. Cost-effectiveness of routine computed tomography in the evaluation of idiopathic unilateral vocal fold paralysis.

    Science.gov (United States)

    Hojjat, Houmehr; Svider, Peter F; Folbe, Adam J; Raza, Syed N; Carron, Michael A; Shkoukani, Mahdi A; Merati, Albert L; Mayerhoff, Ross M

    2017-02-01

    To evaluate the cost-effectiveness of routine computed tomography (CT) in individuals with unilateral vocal fold paralysis (UVFP) STUDY DESIGN: Health Economics Decision Tree Analysis METHODS: A decision tree was constructed to determine the incremental cost-effectiveness ratio (ICER) of CT imaging in UVFP patients. Univariate sensitivity analysis was utilized to calculate what the probability of having an etiology of the paralysis discovered would have to be to make CT with contrast more cost-effective than no imaging. We used two studies examining findings in UVFP patients. The decision pathways were utilizing CT neck with intravenous contrast after diagnostic laryngoscopy versus laryngoscopy alone. The probability of detecting an etiology for UVFP and associated costs were extracted to construct the decision tree. The only incorrect diagnosis was missing a mass in the no-imaging decision branch, which rendered an effectiveness of 0. The ICER of using CT was $3,306, below most acceptable willingness-to-pay (WTP) thresholds. Additionally, univariate sensitivity analysis indicated that at the WTP threshold of $30,000, obtaining CT imaging was the most cost-effective choice when the probability of having a lesion was above 1.7%. Multivariate probabilistic sensitivity analysis with Monte Carlo simulations also showed that at the WTP of $30,000, CT scanning is more cost-effective, with 99.5% certainty. Particularly in the current healthcare environment characterized by increasing consciousness of utilization defensive medicine, economic evaluations represent evidence-based findings that can be employed to facilitate appropriate decision making and enhance physician-patient communication. This economic evaluation strongly supports obtaining CT imaging in patients with newly diagnosed UVFP. 2c. Laryngoscope, 2016 127:440-444, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

  2. Estimation of effective doses in pediatric X-ray computed tomography examination.

    Science.gov (United States)

    Obara, Hideki; Takahashi, Midori; Kudou, Kazuya; Mariya, Yasushi; Takai, Yoshihiro; Kashiwakura, Ikuo

    2017-11-01

    X-ray computed tomography (CT) images are used for diagnostic and therapeutic purposes in various medical disciplines. In Japan, the number of facilities that own diagnostic CT equipment, the number of CT examinations and the number of CT scanners increased by ~1.4-fold between 2005 and 2011. CT operators (medical radiological technologists, medical physicists and physicians) must understand the effective doses for examinations at their own institutions and carefully approach each examination. In addition, the patients undergoing the examination (as well as his/her family) must understand the effective dose of each examination in the context of the cumulative dose. In the present study, the numbers of pediatric patients (aged 0-5 years) and total patients who underwent CT at Hirosaki University Hospital (Hirosaki, Japan) between January 2011 and December 2013 were surveyed, and effective doses administered to children aged 0, 1 and 5 years were evaluated. Age- and region-specific conversion factors and dose-length products obtained from the CT scanner were used to estimate the effective doses. The numbers of CT examinations performed in 2011, 2012 and 2013 were 16,662, 17,491 and 17,649, respectively, of which 613 (1.2%) of the overall total involved children aged 0-5 years. The estimated effective doses per examination to children aged 0, 1 and 5 years were 6.3±4.8, 4.9±3.8 and 2.7±3.0 mSv, respectively. This large variation was attributed to several factors associated with scan methods and ranges in actual setting. In conclusion, the requirement for individual patient prospective exposure management systems and estimations of low-dose radiation exposure should be considered in light of the harmful effects of exposure.

  3. Quantitative Analysis of "1"8F-Fluorodeoxyglucose Positron Emission Tomography Identifies Novel Prognostic Imaging Biomarkers in Locally Advanced Pancreatic Cancer Patients Treated With Stereotactic Body Radiation Therapy

    International Nuclear Information System (INIS)

    Cui, Yi; Song, Jie; Pollom, Erqi; Alagappan, Muthuraman; Shirato, Hiroki; Chang, Daniel T.; Koong, Albert C.; Li, Ruijiang

    2016-01-01

    Purpose: To identify prognostic biomarkers in pancreatic cancer using high-throughput quantitative image analysis. Methods and Materials: In this institutional review board–approved study, we retrospectively analyzed images and outcomes for 139 locally advanced pancreatic cancer patients treated with stereotactic body radiation therapy (SBRT). The overall population was split into a training cohort (n=90) and a validation cohort (n=49) according to the time of treatment. We extracted quantitative imaging characteristics from pre-SBRT "1"8F-fluorodeoxyglucose positron emission tomography, including statistical, morphologic, and texture features. A Cox proportional hazard regression model was built to predict overall survival (OS) in the training cohort using 162 robust image features. To avoid over-fitting, we applied the elastic net to obtain a sparse set of image features, whose linear combination constitutes a prognostic imaging signature. Univariate and multivariate Cox regression analyses were used to evaluate the association with OS, and concordance index (CI) was used to evaluate the survival prediction accuracy. Results: The prognostic imaging signature included 7 features characterizing different tumor phenotypes, including shape, intensity, and texture. On the validation cohort, univariate analysis showed that this prognostic signature was significantly associated with OS (P=.002, hazard ratio 2.74), which improved upon conventional imaging predictors including tumor volume, maximum standardized uptake value, and total legion glycolysis (P=.018-.028, hazard ratio 1.51-1.57). On multivariate analysis, the proposed signature was the only significant prognostic index (P=.037, hazard ratio 3.72) when adjusted for conventional imaging and clinical factors (P=.123-.870, hazard ratio 0.53-1.30). In terms of CI, the proposed signature scored 0.66 and was significantly better than competing prognostic indices (CI 0.48-0.64, Wilcoxon rank sum test P<1e-6

  4. The effectiveness of optical coherence tomography for evaluating peri-omplant tissue: A pilot study

    International Nuclear Information System (INIS)

    Sanda, Minoru; Shiota, Makoto; Imakita, Chiharu; Kasugai, Shohei; Sakuyama, Aoi; Sumi, Yasunori

    2016-01-01

    Optical coherence tomography (OCT) has been investigated as a novel diagnostic imaging tool. The utilisation of this equipment has been evaluated through several studies in the field of dentistry. The aim of this preliminary study was to determine through basic experiments the effectiveness of OCT in implant dentistry. To assess detection ability, we captured OCT images of implants in each of the following situations: (1) implants covered with mucosae of various thicknesses that were harvested from the mandibles of pigs; (2) implants installed in the mandibles of pigs; and (3) implants with abutments and crowns fixed with temporary cement. The OCT images were captured before cementation, after cementation, and after removing the excess submucosal cement. If the thickness of the mucosa covering the implant body was less than 1 mm, the images of the implants were clearly detected by OCT. In the implants were installed in pigs' mandibles, it was difficult to capture clear images of the implant and alveolar bone in most of the samples. Remnants of excess cement around the implants were visible in most samples that had a mucosa thickness of less than 3 mm. Currently, OCT imaging of implants is limited. Cement remnants at the submucosal area can be detected in some cases, which can be helpful in preventing peri-implant diseases. Still, though there are some restrictions to its application, OCT could have potential as an effective diagnostic instrument in the field of implant dentistry as well

  5. L{sub 1/2} regularization based numerical method for effective reconstruction of bioluminescence tomography

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xueli, E-mail: xlchen@xidian.edu.cn, E-mail: jimleung@mail.xidian.edu.cn; Yang, Defu; Zhang, Qitan; Liang, Jimin, E-mail: xlchen@xidian.edu.cn, E-mail: jimleung@mail.xidian.edu.cn [School of Life Science and Technology, Xidian University, Xi' an 710071 (China); Engineering Research Center of Molecular and Neuro Imaging, Ministry of Education (China)

    2014-05-14

    Even though bioluminescence tomography (BLT) exhibits significant potential and wide applications in macroscopic imaging of small animals in vivo, the inverse reconstruction is still a tough problem that has plagued researchers in a related area. The ill-posedness of inverse reconstruction arises from insufficient measurements and modeling errors, so that the inverse reconstruction cannot be solved directly. In this study, an l{sub 1/2} regularization based numerical method was developed for effective reconstruction of BLT. In the method, the inverse reconstruction of BLT was constrained into an l{sub 1/2} regularization problem, and then the weighted interior-point algorithm (WIPA) was applied to solve the problem through transforming it into obtaining the solution of a series of l{sub 1} regularizers. The feasibility and effectiveness of the proposed method were demonstrated with numerical simulations on a digital mouse. Stability verification experiments further illustrated the robustness of the proposed method for different levels of Gaussian noise.

  6. The effectiveness of optical coherence tomography for evaluating peri-omplant tissue: A pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Sanda, Minoru; Shiota, Makoto; Imakita, Chiharu; Kasugai, Shohei [Dept. of Oral Implantology and Regenerative Dental Medicine, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo (Japan); Sakuyama, Aoi [Dept. of Oral Surgery, Jichii Medical University Hospital, Tochigi (Japan); Sumi, Yasunori [Div. of Oral and Dental Surgery, Dept. of Advanced Medicine, National Hospital for Geriatric Medicine, National Center for Geriatrics and Gerontology, Obu (Japan)

    2016-09-15

    Optical coherence tomography (OCT) has been investigated as a novel diagnostic imaging tool. The utilisation of this equipment has been evaluated through several studies in the field of dentistry. The aim of this preliminary study was to determine through basic experiments the effectiveness of OCT in implant dentistry. To assess detection ability, we captured OCT images of implants in each of the following situations: (1) implants covered with mucosae of various thicknesses that were harvested from the mandibles of pigs; (2) implants installed in the mandibles of pigs; and (3) implants with abutments and crowns fixed with temporary cement. The OCT images were captured before cementation, after cementation, and after removing the excess submucosal cement. If the thickness of the mucosa covering the implant body was less than 1 mm, the images of the implants were clearly detected by OCT. In the implants were installed in pigs' mandibles, it was difficult to capture clear images of the implant and alveolar bone in most of the samples. Remnants of excess cement around the implants were visible in most samples that had a mucosa thickness of less than 3 mm. Currently, OCT imaging of implants is limited. Cement remnants at the submucosal area can be detected in some cases, which can be helpful in preventing peri-implant diseases. Still, though there are some restrictions to its application, OCT could have potential as an effective diagnostic instrument in the field of implant dentistry as well.

  7. [Qualitative and quantitative diagnostic performance of 320-slice computed tomography for detecting coronary artery disease with respect to atherosclerotic plaque characteristics].

    Science.gov (United States)

    Li, Suhua; Liu, Jinlai; Peng, Long; Dong, Ruimin; Wu, Huilan; Wang, Chenlin; Ni, Qiongqiong; Luo, Yanting; Zhu, Jieming; Chen, Lin

    2014-10-28

    To investigate qualitatively and quantitatively the diagnostic performance of 320-slice CT for detection of coronary artery disease with respect to different atherosclerotic plaque characteristics. A retrospective search was performed for inpatients underwent both coronary CT and further coronary angiography (CAG) from December 1, 2008 to December 31, 2012. The diagnostic performance of 320-slice CTA for detecting significant stenosis ( ≥ 50% diameter) with respect to atherosclerotic plaque characteristics were analyzed by calculating sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, kappa index (κ), and area under the receiver operating characteristic curve (AUC). Chi-square test was used to evaluate whether there were significant differences of the true-case frequency (true positive + true negative) and false-case frequency (false positive + false negative) among groups. Bland-Altman analysis was used to determine limits of agreement between CTA and CAG. A total of 454 patients and 6 779 segments were analyzed. Diagnostic accuracy was higher in non-calcified segments; whereas they decreased in the presence of both mild-moderately and heavily calcified plaques. Excellent agreement (κ = 0.810) between CT and CAG was observed for non-calcified segments, while good agreement was observed for both mild-moderately (κ = 0.701) and heavily calcified segments (κ = 0.750). Both mild-moderate (P = 0.000) and heavy (P = 0.000) calcification decreased the true-case frequency and increased the false-case frequency when compared to non-calcification. There were no significant underestimation or overestimation for non-calcified (P = 0.087) and mild-moderately calcified (P = 0.704) segments, while there was significant overestimation for heavily calcified segments (P = 0.001). Great qualitative and quantitative diagnostic performances of 320-slice CT were observed in non-calcified coronary segments. However, qualitative

  8. Computer-aided diagnosis in phase contrast imaging X-ray computed tomography for quantitative characterization of ex vivo human patellar cartilage.

    Science.gov (United States)

    Nagarajan, Mahesh B; Coan, Paola; Huber, Markus B; Diemoz, Paul C; Glaser, Christian; Wismuller, Axel

    2013-10-01

    Visualization of ex vivo human patellar cartilage matrix through the phase contrast imaging X-ray computed tomography (PCI-CT) has been previously demonstrated. Such studies revealed osteoarthritis-induced changes to chondrocyte organization in the radial zone. This study investigates the application of texture analysis to characterizing such chondrocyte patterns in the presence and absence of osteoarthritic damage. Texture features derived from Minkowski functionals (MF) and gray-level co-occurrence matrices (GLCM) were extracted from 842 regions of interest (ROI) annotated on PCI-CT images of ex vivo human patellar cartilage specimens. These texture features were subsequently used in a machine learning task with support vector regression to classify ROIs as healthy or osteoarthritic; classification performance was evaluated using the area under the receiver operating characteristic curve (AUC). The best classification performance was observed with the MF features perimeter (AUC: 0.94 ±0.08 ) and "Euler characteristic" (AUC: 0.94 ±0.07 ), and GLCM-derived feature "Correlation" (AUC: 0.93 ±0.07). These results suggest that such texture features can provide a detailed characterization of the chondrocyte organization in the cartilage matrix, enabling classification of cartilage as healthy or osteoarthritic with high accuracy.

  9. Computer-aided diagnosis for phase-contrast X-ray computed tomography: quantitative characterization of human patellar cartilage with high-dimensional geometric features.

    Science.gov (United States)

    Nagarajan, Mahesh B; Coan, Paola; Huber, Markus B; Diemoz, Paul C; Glaser, Christian; Wismüller, Axel

    2014-02-01

    Phase-contrast computed tomography (PCI-CT) has shown tremendous potential as an imaging modality for visualizing human cartilage with high spatial resolution. Previous studies have demonstrated the ability of PCI-CT to visualize (1) structural details of the human patellar cartilage matrix and (2) changes to chondrocyte organization induced by osteoarthritis. This study investigates the use of high-dimensional geometric features in characterizing such chondrocyte patterns in the presence or absence of osteoarthritic damage. Geometrical features derived from the scaling index method (SIM) and statistical features derived from gray-level co-occurrence matrices were extracted from 842 regions of interest (ROI) annotated on PCI-CT images of ex vivo human patellar cartilage specimens. These features were subsequently used in a machine learning task with support vector regression to classify ROIs as healthy or osteoarthritic; classification performance was evaluated using the area under the receiver-operating characteristic curve (AUC). SIM-derived geometrical features exhibited the best classification performance (AUC, 0.95 ± 0.06) and were most robust to changes in ROI size. These results suggest that such geometrical features can provide a detailed characterization of the chondrocyte organization in the cartilage matrix in an automated and non-subjective manner, while also enabling classification of cartilage as healthy or osteoarthritic with high accuracy. Such features could potentially serve as imaging markers for evaluating osteoarthritis progression and its response to different therapeutic intervention strategies.

  10. Analysis of changes in sagging type ST-T segment induced by exercise. Assessment of regional myocardial blood flow using quantitative 13NH3 positron emission tomography

    International Nuclear Information System (INIS)

    Watanabe, Takuya; Akutsu, Yasushi; Okazaki, Osamu

    1995-01-01

    Regional myocardial blood flow (RMBF) associated with exercise-induced ST depression was assessed using 13 NH 3 positron emission tomography (PET) to determine the significance of horizontal and sagging type ST segments. The subjects were 25 patients with angina pectoris, 25 patients with myocardial infarction, and 5 healthy male volunteers. Eleven regions of interests (ROI) were prepared to calculate RMBF. ST segments were unchanged in 27 patients (Group A) and were depressed in 23 patients (Group B). A 10% increase in RMBF was significantly observed in Group A (74.1%) than Group B (34.8%). In Group B, ST depression was divided into horizontal type (8 patients) and sagging type (15 patients). According to the type of ST depression, RMBF was increased by 10% or more in 50% (4/8) for horizontal type and in 26.7% (4/15) for sagging type. These findings suggested that unfavorable increase in RMBF in stenosiss-related coronary vessels may contribute to the development of ST depression induced by exercise. A constant increase in RMBF in all ROIs, including those with unfavorable RMBF increase, may be involved in the occurrence of horizontal type ST depression; sagging type ST depression may, however, occur by an increased difference in blood flow between unfavorable and favorable RMBF. (N.K.)

  11. Methodological study of aging effects on fuel cells using X-ray synchrotron radiography and tomography

    International Nuclear Information System (INIS)

    Arlt, Tobias

    2012-01-01

    In the present work, new and advanced methods for the investigation of methanol and hydrogen powered fuel cells were analyzed. Synchrotron radiography and tomography were applied to investigate materials and transport processes in operating fuel cells ''in-situ'' and non-destructively. The corrosion of ruthenium is a key issue during aging of direct methanol fuel cells (DMFC). Therefore the influence of different aging processes on the distribution of ruthenium is of great interesting. An imaging method based on X-ray absorption spectroscopy (XAS) was applied to investigate the changes in the distribution of fuel cell catalysts three-dimensionally. Using monoenergetic synchrotron radiation it was shown that the distribution of ruthenium (Ru) in the anode catalyst changes after application of an accelerated aging procedure. A strong influence on the flowfield and the gas diffusion layer structures on the Ru distribution were found in the gas diffusion electrode at the anode side. Additionally some ruthenium moves through the membrane from the anode to the cathode. The redistribution caused by the accelerated aging procedure strongly differs from that obtained after aging under realistic stack operation (here over 1700 h) of a fuel cell in a pallet transporter. For the tomographic investigations samples were taken out from a stack operation in aged membrane electrode assembly (MEA) and were analyzed ex-situ. It was shown that the Ru redistribution can be attributed to mass transport processes (CO 2 and H 2 O) in the gas diffusion layer (GDL). Other high energy resolved measurements showed that the strength of the oxidation of ruthenium and platinum depends on the spatial distribution of the ruthenium. Last mentioned - also for the platinum catalyst - could be given quantitatively by means of this newly developed method. In the second part of this work high temperature polymer electrolyte fuel cells (HT-PEFC) were investigated. No liquid water can

  12. Discussions on the non-equilibrium effects in the quantitative phase field model of binary alloys

    International Nuclear Information System (INIS)

    Zhi-Jun, Wang; Jin-Cheng, Wang; Gen-Cang, Yang

    2010-01-01

    All the quantitative phase field models try to get rid of the artificial factors of solutal drag, interface diffusion and interface stretch in the diffuse interface. These artificial non-equilibrium effects due to the introducing of diffuse interface are analysed based on the thermodynamic status across the diffuse interface in the quantitative phase field model of binary alloys. Results indicate that the non-equilibrium effects are related to the negative driving force in the local region of solid side across the diffuse interface. The negative driving force results from the fact that the phase field model is derived from equilibrium condition but used to simulate the non-equilibrium solidification process. The interface thickness dependence of the non-equilibrium effects and its restriction on the large scale simulation are also discussed. (cross-disciplinary physics and related areas of science and technology)

  13. Quantitative computed tomography measurements to evaluate airway disease in chronic obstructive pulmonary disease: Relationship to physiological measurements, clinical index and visual assessment of airway disease

    Energy Technology Data Exchange (ETDEWEB)

    Nambu, Atsushi, E-mail: nambu-a@gray.plala.or.jp [Department of Radiology, National Jewish Health, 1400 Jackson Street, Denver, CO, 80206 (United States); Zach, Jordan, E-mail: ZachJ@NJHealth.org [Department of Radiology, National Jewish Health, 1400 Jackson Street, Denver, CO, 80206 (United States); Schroeder, Joyce, E-mail: Joyce.schroeder@stanfordalumni.org [Department of Radiology, National Jewish Health, 1400 Jackson Street, Denver, CO, 80206 (United States); Jin, Gongyoung, E-mail: gyjin@chonbuk.ac.kr [Department of Radiology, National Jewish Health, 1400 Jackson Street, Denver, CO, 80206 (United States); Kim, Song Soo, E-mail: haneul88@hanmail.net [Department of Radiology, National Jewish Health, 1400 Jackson Street, Denver, CO, 80206 (United States); Kim, Yu-IL, E-mail: kyionly@chonnam.ac.kr [Department of Medicine, National Jewish Health, Denver, CO (United States); Schnell, Christina, E-mail: SchnellC@NJHealth.org [Department of Medicine, National Jewish Health, Denver, CO (United States); Bowler, Russell, E-mail: BowlerR@NJHealth.org [Division of Pulmonary Medicine, Department of Medicine, National Jewish Health (United States); Lynch, David A., E-mail: LynchD@NJHealth.org [Department of Radiology, National Jewish Health, 1400 Jackson Street, Denver, CO, 80206 (United States)

    2016-11-15

    Purpose: To correlate currently available quantitative CT measurements for airway disease with physiological indices and the body-mass index, airflow obstruction, dyspnea, and exercise capacity (BODE) index in patients with chronic obstructive pulmonary disease (COPD). Materials and methods: This study was approved by our institutional review board (IRB number 2778). Written informed consent was obtained from all subjects. The subjects included 188 current and former cigarette smokers from the COPDGene cohort who underwent inspiratory and expiratory CT and also had physiological measurements for the evaluation of airflow limitation, including FEF25-75%, airway resistance (Raw), and specific airway conductance (sGaw). The BODE index was used as the index of clinical symptoms. Quantitative CT measures included % low attenuation areas [% voxels ≤ 950 Hounsfield unit (HU) on inspiratory CT, %LAA{sub −950ins}], percent gas trapping (% voxels ≤ −856 HU on expiratory CT, %LAA {sub −856exp}), relative inspiratory to expiratory volume change of voxels with attenuation values from −856 to −950 HU [Relative Volume Change (RVC){sub −856} {sub to} {sub −950}], expiratory to inspiratory ratio of mean lung density (E/I-ratio {sub MLD}), Pi10, and airway wall thickness (WT), luminal diameter (LD) and airway wall area percent (WA%) in the segmental, subsegmental and subsubsegmental bronchi on inspiratory CT. Correlation coefficients were calculated between the QCT measurements and physiological measurements in all subjects and in the subjects with mild emphysema (%LAA{sub −950ins} <10%). Univariate and multiple variable analysis for the BODE index were also performed. Adjustments were made for age, gender, smoking pack years, FEF25-75%, Raw, and sGaw. Results: Quantitative CT measurements had significant correlations with physiological indices. Among them, E/I-ratio {sub MLD} had the strongest correlations with FEF25-75% (r = −0.648, <0.001) and sGaw (r = −0

  14. Quantitative radiography

    International Nuclear Information System (INIS)

    Brase, J.M.; Martz, H.E.; Waltjen, K.E.; Hurd, R.L.; Wieting, M.G.

    1986-01-01

    Radiographic techniques have been used in nondestructive evaluation primarily to develop qualitative information (i.e., defect detection). This project applies and extends the techniques developed in medical x-ray imaging, particularly computed tomography (CT), to develop quantitative information (both spatial dimensions and material quantities) on the three-dimensional (3D) structure of solids. Accomplishments in FY 86 include (1) improvements in experimental equipment - an improved microfocus system that will give 20-μm resolution and has potential for increased imaging speed, and (2) development of a simple new technique for displaying 3D images so as to clearly show the structure of the object. Image reconstruction and data analysis for a series of synchrotron CT experiments conducted by LLNL's Chemistry Department has begun

  15. Cost-effectiveness of implementing computed tomography screening for lung cancer in Taiwan.

    Science.gov (United States)

    Yang, Szu-Chun; Lai, Wu-Wei; Lin, Chien-Chung; Su, Wu-Chou; Ku, Li-Jung; Hwang, Jing-Shiang; Wang, Jung-Der

    2017-06-01

    A screening program for lung cancer requires more empirical evidence. Based on the experience of the National Lung Screening Trial (NLST), we developed a method to adjust lead-time bias and quality-of-life changes for estimating the cost-effectiveness of implementing computed tomography (CT) screening in Taiwan. The target population was high-risk (≥30 pack-years) smokers between 55 and 75 years of age. From a nation-wide, 13-year follow-up cohort, we estimated quality-adjusted life expectancy (QALE), loss-of-QALE, and lifetime healthcare expenditures per case of lung cancer stratified by pathology and stage. Cumulative stage distributions for CT-screening and no-screening were assumed equal to those for CT-screening and radiography-screening in the NLST to estimate the savings of loss-of-QALE and additional costs of lifetime healthcare expenditures after CT screening. Costs attributable to screen-negative subjects, false-positive cases and radiation-induced lung cancer were included to obtain the incremental cost-effectiveness ratio from the public payer's perspective. The incremental costs were US$22,755 per person. After dividing this by savings of loss-of-QALE (1.16 quality-adjusted life year (QALY)), the incremental cost-effectiveness ratio was US$19,683 per QALY. This ratio would fall to US$10,947 per QALY if the stage distribution for CT-screening was the same as that of screen-detected cancers in the NELSON trial. Low-dose CT screening for lung cancer among high-risk smokers would be cost-effective in Taiwan. As only about 5% of our women are smokers, future research is necessary to identify the high-risk groups among non-smokers and increase the coverage. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  16. Quantitative analysis of inclusions in high-strength steels by x-ray computed tomography using ultra-bright synchrotron radiation

    International Nuclear Information System (INIS)

    Shiozawa, Daiki; Nakai, Yoshikazu; Morikage, Yasushi; Tanaka, Hiroshi; Okado, Hideki; Miyashita, Takuya

    2006-01-01

    The observation of internal microstructures in materials is important to elucidate the mechanisms of ultra-long life fatigue of high-strength steels, and to ensure the integrity of structures. By conventional techniques, such as laboratory X-ray and ultrasonic imaging, the size and shape of subsurface non-metallic inclusions and cracks, those are smaller than 100 μm, cannot be measured. Then, in the present study, the ultra-bright synchrotron radiation X-ray was applied to the imaging of subsurface inclusion. To obtain basic data for the measurement, the penetration depth of synchrotron radiation wave in a free-cutting steel was examined. It was found that the depths where the transmitted wave cannot be observed are 100 μm for 15 keV, 200 μm for 20 keV, 600 μm for 25 keV, and 800 μm for 30 keV. For the measurement of size and shape of inclusion, synchrotron radiation computed tomography method (SR-CT) was employed. Metallographic structures can be observed in a free-cutting steel, and the diameter of these structures is about 7 - 10 μm. They are considered to be inclusions, which mainly contain manganese sulfide (MnS) or pearlitic phase. To investigate the possibility of detection of pearlitic phase, SR-CT was applied to observe the metallographic structures in carbon steel (S35C), which contains a lot of pearlitic phase and a little inclusion. In this case, no metallographic structure was observed inside specimen. These results indicate that the microstructures those were observed by SR-CT method was inclusions, not pearlitic phase. (author)

  17. Quantitative perfusion computed tomography measurements of cerebral hemodynamics: Correlation with digital subtraction angiography identified primary and secondary cerebral collaterals in i