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Sample records for adenosine dual source

  1. 2-Aminopyrimidines as dual adenosine A1/A2A antagonists.

    Robinson, Sarel J; Petzer, Jacobus P; Terre'Blanche, Gisella; Petzer, Anél; van der Walt, Mietha M; Bergh, Jacobus J; Lourens, Anna C U

    2015-11-01

    In this study thirteen 2-aminopyrimidine derivatives were synthesised and screened as potential antagonists of adenosine A1 and A2A receptors in order to further investigate the structure activity relationships of this class of compounds. 4-(5-Methylfuran-2-yl)-6-[3-(piperidine-1-carbonyl)phenyl]pyrimidin-2-amine (8m) was identified as a compound with high affinities for both receptors, with an A2AKi value of 6.34 nM and an A1Ki value of 9.54 nM. The effect of selected compounds on the viability of cultured cells was assessed and preliminary results indicate low cytotoxicity. In vivo efficacy at A2A receptors was illustrated for compounds 8k and 8m since these compounds attenuated haloperidol-induced catalepsy in rats. A molecular docking study revealed that the interactions between the synthesised compounds and the adenosine A2A binding site most likely involve Phe168 and Asn253, interactions which are similar for structurally related adenosine A2A receptor antagonists. PMID:26462195

  2. Extracellular nucleotide catabolism in human B and T lymphocytes. The source of adenosine production

    Extracellular nucleotide degradation was studied in intact human B and T lymphocyte subpopulations and in lymphoblastoid cell lines. Cells of B lymphocyte lineage showed high nucleotide degrading activity, whereas T lymphocytes were unable to degrade extracellular nucleotides. The external surface of B cells contained active sites of ecto-triphosphonucleotidase (ecto-ATPase), ecto-diphosphonucleotidase (ecto-ADPase), and ecto-monophosphonucleotidase (ecto-AMPase). The expression of all three ectoenzyme activities seemed closely associated with B cell development. ATPase and ADPase activities increase continuously during B cell maturation, ecto-AMPase activity, on the other hand, reaches maximal activity in late pre-B cells. These results combined with our previous studies of intracellular ATP catabolism provide evidence that extracellular ATP catabolism may represent exclusive source for adenosine in lymphocytes. It is suggested that adenosine may serve as a means of communication between B and T cells in lymphoid organs, B lymphocytes being the sole producers of adenosine and T lymphocytes being the recipients of this signal

  3. Principle and applications of dual source CT

    Flohr, Thomas

    2008-08-01

    Dual source CT (DSCT) has the potential to solve remaining limitations of conventional multi-detector row CT (MDCT)-scanners, such as insufficient temporal resolution for ECG-controlled cardiac imaging. A DSCT is equipped with two X-ray tubes and two corresponding detectors that are mounted onto the rotating gantry with an angular offset of 90°. The key benefit of DSCT for cardiac scanning is improved temporal resolution equivalent to a quarter of the gantry rotation time (83 ms at 0.33 s rotation time). Additionally, both X-ray tubes can be operated at different kV- and mA-settings, enabling the acquisition of dual energy data. The acquisition of dual energy CT data can add functional information to the morphological information based on different X-ray attenuation coefficients that is usually obtained in a CT examination.

  4. Modular dual-source tomographic scanner

    Dolský, František; Fíla, Tomáš; Vavřík, Daniel; Kumpová, Ivana

    Brno: Central European Institute of Technology, 2015. s. 66-66 ISBN N. [Creating life in 3D. Conference on frontiers in materials and life sciences. 02.09.2015-04.09.2015, Brno] R&D Projects: GA MŠk(CZ) LO1219 Keywords : multi-purpose X-ray device * computed tomography * dual source CT (DSCT) Subject RIV: AL - Art, Architecture, Cultural Heritage http://www.ceitec.eu/a5-abstracts-book-3d/f33102

  5. Virtual monochromatic imaging in dual-source dual-energy CT: Radiation dose and image quality

    Yu, Lifeng; Christner, Jodie A.; Leng, Shuai; Wang, Jia; Fletcher, Joel G.; McCollough, Cynthia H.

    2011-01-01

    Purpose: To evaluate the image quality of virtual monochromatic images synthesized from dual-source dual-energy computed tomography (CT) in comparison with conventional polychromatic single-energy CT for the same radiation dose.

  6. Technical principles of dual source CT

    Petersilka, Martin [Siemens Health Care, Forchheim (Germany)], E-mail: martin.petersilka@siemens.com; Bruder, Herbert; Krauss, Bernhard; Stierstorfer, Karl [Siemens Health Care, Forchheim (Germany); Flohr, Thomas G. [Siemens Health Care, Forchheim (Germany); Department of Diagnostic Radiology, Eberhard-Karls-Universitaet, Tuebingen (Germany)

    2008-12-15

    During the past years, multi-detector row CT (MDCT) has evolved into clinical practice with a rapid increase of the number of detector slices. Today's 64 slice CT systems allow whole-body examinations with sub-millimeter resolution in short scan times. As an alternative to adding even more detector slices, we describe the system concept and design of a CT scanner with two X-ray tubes and two detectors (mounted on a CT gantry with a mechanical offset of 90 deg.) that has the potential to overcome limitations of conventional MDCT systems, such as temporal resolution for cardiac imaging. A dual source CT (DSCT) scanner provides temporal resolution equivalent to a quarter of the gantry rotation time, independent of the patient's heart rate (83 ms at 0.33 s rotation time). In addition to the benefits for cardiac scanning, it allows to go beyond conventional CT imaging by obtaining dual energy information if the two tubes are operated at different voltages. Furthermore, we discuss how both acquisition systems can be used to add the power reserve of two X-ray tubes for long scan ranges and obese patients. Finally, future advances of DSCT are highlighted.

  7. Flash imaging in dual source CT (DSCT)

    Bruder, H.; Petersilka, M.; Mehldau, H.; Heidinger, W.; Allmendinger, T.; Schmidt, B.,; Raupach, R.; Thierfelder, C.,; Stierstorfer, K.; Flohr, T.

    2009-02-01

    We present new acquisition modes of a recently introduced dual-source computed tomography (DSCT) system equipped with two X-ray tubes and two corresponding detectors, mounted onto the rotating gantry with an angular offset of typically 90°. Due to the simultaneous acquisition of complementary data, the minimum exposure time is reduced by a factor of two compared to a single-source CT system (SSCT). The correspondingly improved temporal resolution is beneficial for cardiac CT. Also, maximum table feed per rotation in a spiral mode can be increased by a factor of 2 compared to SSCT, which provides benefits both for cardiac CT and non-cardiac CT. In an ECG-triggered mode the entire cardiac volume can be scanned within a fraction of one cardiac RR-cycle. At a rotation time of 0.28s using a detector with 64×0.6 mm beam collimation, the scan time of the entire heart is less than 0.3s at a temporal resolution of 75 ms. It will be shown, that the extremely fast cardiac scan reduces the patient dose to a theoretical lowest limit: for a 120 kV scan the dose level for a typical cardiac CT scan is well below 2 mSv. Using further protocol optimization (scan range adaptation, 100kV), the radiation dose can be reduced below 1mSv.

  8. Thoracic applications of dual-source CT technology

    Boroto, Kahimano [Department of Thoracic Imaging, Hospital Calmette, University Center of Lille, Boulevard Jules Leclercq, 59037 Lille Cedex (France); Remy-Jardin, Martine [Department of Thoracic Imaging, Hospital Calmette, University Center of Lille, Boulevard Jules Leclercq, 59037 Lille Cedex (France)], E-mail: mremy-jardin@chru-lille.fr; Flohr, Thomas [Department of Research and Development, Siemens Medical Solutions, Siemensstr. 1, 91301 Forchheim (Germany); Faivre, Jean-Baptiste; Pansini, Vittorio; Tacelli, Nunzia [Department of Thoracic Imaging, Hospital Calmette, University Center of Lille, Boulevard Jules Leclercq, 59037 Lille Cedex (France); Schmidt, Bernhard [Department of Research and Development, Siemens Medical Solutions, Siemensstr. 1, 91301 Forchheim (Germany); Gorgos, Andrei; Remy, Jacques [Department of Thoracic Imaging, Hospital Calmette, University Center of Lille, Boulevard Jules Leclercq, 59037 Lille Cedex (France)

    2008-12-15

    Among the various imaging modalities available, CT has remained over time the core imaging technique for the evaluation of respiratory disorders. The recent advent of dual-source CT offers innovative approaches to investigate thoracic diseases, based on the use of one or two tubes as well as single or dual energy to scan the entire thorax. Two major options can be used in clinical practice with promising results. Dual source, single-energy scanning allows scanning of the entire thorax with ultra-high temporal resolution which opens the field of integrated cardiothoracic imaging without ECG gating as well as optimized evaluation of pediatric and adult patients with limited ability to cooperate. Dual-source, dual-energy acquisitions represent another very innovative means of investigating respiratory disorders, adding tissue characterization and functional analysis to morphological evaluation. The purpose of this review article is to provide results on preliminary experiences with the above-mentioned scanning conditions with dual-source CT and to envisage potential forthcoming applications in the field of thoracic imaging.

  9. Thoracic applications of dual-source CT technology

    Among the various imaging modalities available, CT has remained over time the core imaging technique for the evaluation of respiratory disorders. The recent advent of dual-source CT offers innovative approaches to investigate thoracic diseases, based on the use of one or two tubes as well as single or dual energy to scan the entire thorax. Two major options can be used in clinical practice with promising results. Dual source, single-energy scanning allows scanning of the entire thorax with ultra-high temporal resolution which opens the field of integrated cardiothoracic imaging without ECG gating as well as optimized evaluation of pediatric and adult patients with limited ability to cooperate. Dual-source, dual-energy acquisitions represent another very innovative means of investigating respiratory disorders, adding tissue characterization and functional analysis to morphological evaluation. The purpose of this review article is to provide results on preliminary experiences with the above-mentioned scanning conditions with dual-source CT and to envisage potential forthcoming applications in the field of thoracic imaging

  10. Drive Current Enhancement in TFET by Dual Source Region

    Zhi Jiang

    2015-01-01

    Full Text Available This paper presents tunneling field-effect transistor (TFET with dual source regions. It explores the physics of drive current enhancement. The novel approach of dual source provides an effective technique for enhancing the drive current. It is found that this structure can offer four tunneling junctions by increasing a source region. Meanwhile, the dual source structure does not influence the excellent features of threshold slope (SS of TFET. The number of the electrons and holes would be doubled by going through the tunneling junctions on the original basis. The overlap length of gate-source is also studied. The dependence of gate-drain capacitance Cgd and gate-source capacitance Cgs on gate-to-source voltage Vgs and drain-to-source voltage Vds was further investigated. There are simulation setups and methodology used for the dual source TFET (DS-TFET assessment, including delay time, total energy per operation, and energy-delay product. It is confirmed that the proposed TFET has strong potentials for VLSI.

  11. Cerebral artery evaluation of dual energy CT angiography with dual source CT

    MA Rui; LIU Cheng; DENG Kai; SONG Shao-juan; WANG Dao-ping; HUANG Ling

    2010-01-01

    Background Conventional computed tomography angiography (CTA) is time consuming, user-dependent and has poor image quality in skull base region. This study assessed the feasibility of a new method, dual energy CTA for depicting the cerebral artery.Methods Phantom scan was done with head CTA sequences on dual source CT and 64 spiral CT for radiation dose calculation. Dual energy CTA was done with dual source CT on 36 patients who were suspected of having cerebral vascular disease. Three series axial images in 0.75 mm thick, 0.4 mm increment were acquired, which were named with 80 kV, 140 kV and merged images; 80 kV and 140 kV images were transferred into dual energy software, and maximum intensity projection (MIP) image was generated quickly by dual energy bone remove (DEBR group); merged images were transferred into In Space software to acquire MIP image through manual conventional bone remove (CoBR group). Post processing time and reading time were compared. Image qualities of the two groups were compared, mainly focusing on skull base segments of internal carotid artery and bone subtraction. ANOVA and SNK tests were applied for radiation dose comparison. Student's t test and Wilcoxon rank sum test were applied for assessing differences between data for significance. Cohen's kappa was used for interobserver agreement. Results Radiation dose of phantom scan showed dual energy CTA was between digital bone subtraction and conventional CTA. The post processing time and reading time were much shorter in DEBR than CoBR, and image quality in skull base was much higher in DEBR than CoBR (P0.5). Interobserver agreement for all vessel segments was excellent (kappa=0.97). Conclusions Dual energy CTA is a reliable, new modality for depicting cerebral artery, overcoming the limitation of conventional CTA in the skull base region. It can save much time in post processing and reading than conventional CTA.

  12. Dual chamber laser ion source at LISOL

    Kudryavtsev, Yuri; Cocolios, Thomas Elias; Gentens, Johnny; Huyse, Marc; Ivanov, Oleg; Pauwels, Dieter; Sonoda, Tetsu; Van den Bergh, Paul; Van Duppen, Piet

    2009-01-01

    A new type of gas cell for the resonance ionization laser ion source at the Leuven Isotope Separator On Line (LISOL) has been developed and tested under off-line and on-line conditions. Two-step selective laser ionization is applied to produce purified beams of radioactive isotopes. The selectivity of the ion source has been increased by more than one order of magnitude by separation of the stopping and laser ionization regions. This allows the use of electrical fields for further ion purific...

  13. Dual radio frequency plasma source: Understanding via electrical asymmetry effect

    On the basis of the global model, the influences of driving voltage and frequency on electron heating in geometrically symmetrical dual capacitively coupled radio frequency plasma have been investigated. Consistent with the experimental and simulation results, non-monotonic behavior of dc self bias and plasma heating with increasing high frequency is observed. In addition to the local maxima of plasma parameters for the integer values of the ratio between the frequencies (ξ), ourstudies also predict local maxima for odd integer values of 2ξ as a consequence of the electrical asymmetry effect produced by dual frequency voltage sources.

  14. In vitro differentiation of renal stone composition using dual-source, dual-energy CT

    Objective: To evaluate the ability of dual-source. dual-energy CT in differentiating uric acid stones from non-uric acid stones with infrared spectroscopy as reference standard. Materials and Methods: Urinary calculus from 308 patients were scanned in first generation dual-source CT with dual-energy mode between July 2011 and June 2012. Renal Stone application was used to analyze their composition. The uric acid stones color were coded red and non-uric acid stones were blue. CT values were measured in 60 selective urinary calculus including 30 uric acid stones and 30 non-uric acid stones. The accuracy of dual energy CT to differentiate uric acid and no-uric acid stones was calculated. Results: Of 308 patients, 60 patients had uric acid stones and 248 non-uric acid stones. No difference was found for uric acid stone at 80 kV and 140 kV (375.8±69.2 HU vs. 374.1±69.4 HU; t=-0.217, P=0.830), while CT values of non-uric acid stones were higher at 80 kV than those at 140 kV (1455.1±312.4 HU vs. 1039.6±194.4 HU; t=-12.16. P<0.001). CT values of non-uric acid stones at 80 kV, 140 kV, and average weighted images (1455.1±312.4 HU, 1 039.6±194.4 HU, and 882.0±176.4 HU, respectively) were higher than those of uric acid stones (375.8±69.2 HU, 374.1±69.4 HU, and 366.3±80.1 HU, respectively; P<0.001). With infrared spectrum findings as reference standard, the accuracy of dual energy CT in differentiating uric acid stones from non-uric acid stones was 100%. Conclusions: Dual-source, dual-energy CT can accurately differentiate uric acid stones from non-uric acid stones, and plays an important role in treatment planning of renal stones. (authors)

  15. Preliminary study of single contrast enhanced dual energy heart imaging using dual-source CT

    Objective: To evaluate the feasibility and preliminary applications of single contrast enhanced dual energy heart imaging using dual-source CT (DSCT). Methods: Thirty patients underwent dual energy heart imaging with DSCT, of which 6 cases underwent SPECT or DSA within one week. Two experienced radiologists assessed image quality of coronary arteries and iodine map of myocardium. and correlated the coronary artery stenosis with the perfusion distribution of iodine map. Results: l00% (300/300) segments reached diagnostic standards. The mean score of image for all patients was 4.68±0.57. Mural coronary artery was present in 10 segments in S cases, atherosclerotic plaques in 32 segments in 12 cases, of which 20 segments having ≥50% stenosis, 12 segments ≤50% stenosis; dual energy CT coronary angiography was consistent with the DSA in 3 patients. 37 segmental perfusion abnormalities on iodine map were found in 15 cases, including 28 coronary blood supply segment narrow segment and 9 no coronary stenosis (including three negative segments in SPECD. Conclusion: Single contrast enhanced dual energy heart imaging can provide good coronary artery and myocardium perfusion images in the patients with appropriate heart rate, which has a potential to be used in the clinic and further studies are needed. (authors)

  16. Virtual monochromatic imaging in dual-source dual-energy CT: Radiation dose and image quality

    Purpose: To evaluate the image quality of virtual monochromatic images synthesized from dual-source dual-energy computed tomography (CT) in comparison with conventional polychromatic single-energy CT for the same radiation dose. Methods: In dual-energy CT, besides the material-specific information, one may also synthesize monochromatic images at different energies, which can be used for routine diagnosis similar to conventional polychromatic single-energy images. In this work, the authors assessed whether virtual monochromatic images generated from dual-source CT scanners had an image quality similar to that of polychromatic single-energy images for the same radiation dose. First, the authors provided a theoretical analysis of the optimal monochromatic energy for either the minimum noise level or the highest iodine contrast to noise ratio (CNR) for a given patient size and dose partitioning between the low- and high-energy scans. Second, the authors performed an experimental study on a dual-source CT scanner to evaluate the noise and iodine CNR in monochromatic images. A thoracic phantom with three sizes of attenuating rings was used to represent four adult sizes. For each phantom size, three dose partitionings between the low-energy (80 kV) and the high-energy (140 kV) scans were used in the dual-energy scan. Monochromatic images at eight energies (40 to 110 keV) were generated for each scan. Phantoms were also scanned at each of the four polychromatic single energy (80, 100, 120, and 140 kV) with the same radiation dose. Results: The optimal virtual monochromatic energy depends on several factors: phantom size, partitioning of the radiation dose between low- and high-energy scans, and the image quality metrics to be optimized. With the increase of phantom size, the optimal monochromatic energy increased. With the increased percentage of radiation dose on the low energy scan, the optimal monochromatic energy decreased. When maximizing the iodine CNR in

  17. Dual energy CTA of the supraaortic arteries: Technical improvements with a novel dual source CT system

    Objectives: Computed tomography angiography (CTA) is a well-accepted imaging modality to evaluate the supraaortic vessels. Initial reports have suggested that dual energy CTA (DE-CTA) can enhance diagnosis by creating bone-free data sets, which can be visualized in 3D, but a number of limitations of this technique have also been addressed. We sought to describe the performance of DE-CTA of the supraaortic vessels with a novel dual source CT system with special emphasis on image quality and post-processing related artifacts. Materials and methods: Thirty-three patients underwent carotid CT angiography on a second generation dual source CT system. Simultaneous acquisitions of 100 and 140 kV data sets in arterial phase were performed. Two examiners evaluated overall bone suppression with a 3-point scale (1 = poor; 3 = excellent) and image quality regarding integrity of the vessel lumen of different vessel segments (n = 26) with a 5-point scale (1 = poor; 5 = excellent), CTA source data served as the reference. Results: Excellent bone suppression could be achieved in the head and neck. Only minor bone remnants occurred, mean score for bone removal was 2.9. Mean score for vessel integrity was 4.3. Eight hundred fifty-seven vessel segments could be evaluated. Six hundred thirty-five segments (74%) showed no lumen alteration, 65 segments (7.6%) lumen alterations 10% resulting in a total luminal reduction 50%, and 113 segments (13.2%) showed a gap in the vessel course (100% total lumen reduction). Artificial gaps of the vessel lumen occurred in 28 vessel segments due to artifacts caused by dental hardware and in all but one (65) ophthalmic arteries. Conclusions: Excellent bone suppression could be achieved, DE imaging with 100 and 140 kV lead to improved image quality and vessel integrity in the shoulder region than previously reported. The ophthalmic artery still cannot be adequately visualized.

  18. Versatile compact atomic source for high resolution dual atom interferometry

    Müller, T; Gilowski, M; Jentsch, C; Rasel, E M; Ertmer, W

    2007-01-01

    We present a compact $^{87}$Rb atomic source for high precision dual atom interferometers. The source is based on a double-stage magneto-optical trap (MOT) design, consisting of a 2-dimensional (2D)-MOT for efficient loading of a 3D-MOT. The accumulated atoms are precisely launched in a horizontal moving molasses. Our setup generates a high atomic flux ($>10^{10}$ atoms/s) with precise and flexibly tunable atomic trajectories as required for high resolution Sagnac atom interferometry. We characterize the performance of the source with respect to the relevant parameters of the launched atoms, i.e. temperature, absolute velocity and pointing, by utilizing time-of-flight techniques and velocity selective Raman transitions.

  19. The utilization of dual source CT in imaging of polytrauma

    Despite the growing role of imaging, trauma remains the leading cause of death in people below the age of 45 years in the western industrialized countries. Trauma has been touted as the largest epidemic in the 20th century. The advent of MDCT has been the greatest advance in trauma care in the last 25 years. However, there are still challenges in CT imaging of the polytrauma individual including time restraints, diagnostic errors, radiation dose effects and bridging the gap between anatomy and physiology. This article will analyze these challenges and provide possible solutions offered by the unique design of the dual source CT scanner

  20. Dual-source CT cardiac imaging: initial experience

    The relation of heart rate and image quality in the depiction of coronary arteries, heart valves and myocardium was assessed on a dual-source computed tomography system (DSCT). Coronary CT angiography was performed on a DSCT (Somatom Definition, Siemens) with high concentration contrast media (Iopromide, Ultravist 370, Schering) in 24 patients with heart rates between 44 and 92 beats per minute. Images were reconstructed over the whole cardiac cycle in 10% steps. Two readers independently assessed the image quality with regard to the diagnostic evaluation of right and left coronary artery, heart valves and left ventricular myocardium for the assessment of vessel wall changes, coronary stenoses, valve morphology and function and ventricular function on a three point grading scale. The image quality ratings at the optimal reconstruction interval were 1.24±0.42 for the right and 1.09±0.27 for the left coronary artery. A reconstruction of diagnostic systolic and diastolic images is possible for a wide range of heart rates, allowing also a functional evaluation of valves and myocardium. Dual-source CT offers very robust diagnostic image quality in a wide range of heart rates. The high temporal resolution now also makes a functional evaluation of the heart valves and myocardium possible. (orig.)

  1. Dual energy CTA of the supraaortic arteries: Technical improvements with a novel dual source CT system

    Lell, Michael M., E-mail: Michael.lell@uk-erlangen.de [Department of Radiology, University Erlangen, Maximiliansplatz 1, 91054 Erlangen (Germany); Hinkmann, Fabian [Department of Radiology, University Erlangen, Maximiliansplatz 1, 91054 Erlangen (Germany); Nkenke, Emeka [Department of Maxillofacial Surgery, University Erlangen (Germany); Schmidt, Bernhard [Bayer-Schering Healthcare, Berlin (Germany); Seidensticker, Peter [Siemens Healthcare, CT-Division, Forchheim (Germany); Kalender, Willi A. [Institute of Medical Physics, University Erlangen (Germany); Uder, Michael [Department of Radiology, University Erlangen, Maximiliansplatz 1, 91054 Erlangen (Germany); Achenbach, Stephan [Department of Cardiology, University Erlangen (Germany)

    2010-11-15

    Objectives: Computed tomography angiography (CTA) is a well-accepted imaging modality to evaluate the supraaortic vessels. Initial reports have suggested that dual energy CTA (DE-CTA) can enhance diagnosis by creating bone-free data sets, which can be visualized in 3D, but a number of limitations of this technique have also been addressed. We sought to describe the performance of DE-CTA of the supraaortic vessels with a novel dual source CT system with special emphasis on image quality and post-processing related artifacts. Materials and methods: Thirty-three patients underwent carotid CT angiography on a second generation dual source CT system. Simultaneous acquisitions of 100 and 140 kV data sets in arterial phase were performed. Two examiners evaluated overall bone suppression with a 3-point scale (1 = poor; 3 = excellent) and image quality regarding integrity of the vessel lumen of different vessel segments (n = 26) with a 5-point scale (1 = poor; 5 = excellent), CTA source data served as the reference. Results: Excellent bone suppression could be achieved in the head and neck. Only minor bone remnants occurred, mean score for bone removal was 2.9. Mean score for vessel integrity was 4.3. Eight hundred fifty-seven vessel segments could be evaluated. Six hundred thirty-five segments (74%) showed no lumen alteration, 65 segments (7.6%) lumen alterations <10%, 27 segments (3.1%) lumen alterations >10% resulting in a total luminal reduction <50%, 17 segments (2%) lumen alterations of more than 10% resulting in a total luminal reduction >50%, and 113 segments (13.2%) showed a gap in the vessel course (100% total lumen reduction). Artificial gaps of the vessel lumen occurred in 28 vessel segments due to artifacts caused by dental hardware and in all but one (65) ophthalmic arteries. Conclusions: Excellent bone suppression could be achieved, DE imaging with 100 and 140 kV lead to improved image quality and vessel integrity in the shoulder region than previously

  2. Dual-source CT in chest pain diagnosis; Dual-source-CT in der Diagnostik des Thoraxschmerzes

    Johnson, Thorsten R.C.; Nikolaou, K.; Fink, C.; Rist, C.; Reiser, M.F.; Becker, C.R. [Klinikum Grosshadern der Ludwig-Maximilians-Universitaet Muenchen, Institut fuer Klinische Radiologie, Muenchen (Germany); Becker, A.; Knez, A. [Klinikum Grosshadern der Ludwig-Maximilians-Universitaet Muenchen, Abteilung Kardiologie, Medizinische Klinik I, Muenchen (Germany)

    2007-04-15

    With the depiction of pulmonary arteries, coronary arteries, and the aorta, CT angiography of the chest offers a comprehensive diagnostic work-up of unclear chest pain. The aim of this study was to assess the diagnostic accuracy of dual-source CT in this patient group. A total of 47 patients suffering from unclear chest pain were examined with a Siemens Somatom Definition. Volume and flow of contrast media (Ultravist, Schering) were adapted to the body weight. The examinations were evaluated with regard to image quality and contrast opacification and to the diagnostic accuracy with reference to the final clinical diagnosis. Adequate contrast opacification was achieved in all examinations. The depiction of the coronary arteries was diagnostic in all cases. The cause of chest pain could be identified in 41 cases. Among the diagnoses were coronary and myocardial pathologies, valvular disease, aortic aneurysms and dissections, pulmonary embolism, and pneumonic consolidation. DSCT angiography of the chest offers a very good image quality even at high heart rates so that a high diagnostic accuracy is achieved in patients with acute chest pain. (orig.) [German] Die EKG-getriggerte CT-Angiographie kann mit der Darstellung von Koronar-, Lungenarterien und Aorta eine umfassende Abklaerung des unklaren Thoraxschmerzes leisten. Ziel unserer Untersuchungen war es, die diagnostische Wertigkeit des Dual-source-CT in diesem Patientenkollektiv festzustellen. 47 Patienten mit unklarem Thoraxschmerz wurden an einem Siemens Somatom Definition untersucht. Menge und Injektionsgeschwindigkeit des Kontrastmittels (Ultravist, Schering) wurden auf das Koerpergewicht adaptiert. Die Untersuchungen wurden hinsichtlich der Bildqualitaet und Kontrastierung sowie der diagnostischen Genauigkeit im Vergleich zur endgueltigen klinischen Diagnose beurteilt. Bei allen Untersuchungen wurde eine ausreichende Kontrastierung erzielt. Die Darstellung der Koronararterien war in allen Faellen diagnostisch

  3. Dual energy CT with photon counting and dual source systems: comparative evaluation

    Atak, Haluk; Shikhaliev, Polad M.

    2015-12-01

    Recently, new dual energy (DE) computed tomography (CT) systems—dual source CT (DSCT) and photon counting CT (PCCT) have been introduced. Although these systems have the same clinical targets, they have major differences as they use dual and single kVp acquisitions and different x-ray detection and energy resolution concepts. The purpose of this study was theoretical and experimental comparisons of DSCT and PCCT. The DSCT Siemens Somatom Flash was modeled for simulation study. The PCCT had the same configuration as DSCT except it used a photon counting detector. The soft tissue phantoms with 20, 30, and 38 cm diameters included iodine, CaCO3, adipose, and water samples. The dose (air kerma) was 14 mGy for all studies. The low and high energy CT data were simulated at 80 kVp and 140 kVp for DSCT, and in 20-58 keV and 59-120 keV energy ranges for PCCT, respectively. The experiments used Somatom Flash DSCT system and PCCT system based on photon counting CdZnTe detector with 2  ×  256 pixel configuration and 1  ×  1 mm2 pixels size. In simulated general CT images, PCCT provided higher contrast-to-noise ratio (CNR) than DSCT with 0.4/0.8 mm Sn filters. The PCCT with K-edge filter provided higher CNR than the PCCT with a Cu filter, and DSCT with 0.4 mm Sn filter provided higher CNR than the DSCT with a 0.8 mm Sn filter. In simulated DE subtracted images, CNR of the DSCT was comparable to the PCCT with a Cu filter. However, DE PCCT with Ho a K-edge filter provided 30-40% higher CNR than the DE DSCT with 0.4/0.8 mm Sn filters. The experimental PCCT provided higher CNR in general imaging compared to the DSCT. In experimental DE subtracted images, the DSCT provided higher CNR than the PCCT with a Cu filter. However, experimental CNR with DE PCCT with K-edge filter was 15% higher than in DE DSCT, which is less than 30-40% increase predicted by the simulation study. It is concluded that ideal PCCT can provide substantial advantages over ideal

  4. Dual energy CT with photon counting and dual source systems: comparative evaluation

    Recently, new dual energy (DE) computed tomography (CT) systems—dual source CT (DSCT) and photon counting CT (PCCT) have been introduced. Although these systems have the same clinical targets, they have major differences as they use dual and single kVp acquisitions and different x-ray detection and energy resolution concepts. The purpose of this study was theoretical and experimental comparisons of DSCT and PCCT. The DSCT Siemens Somatom Flash was modeled for simulation study. The PCCT had the same configuration as DSCT except it used a photon counting detector. The soft tissue phantoms with 20, 30, and 38 cm diameters included iodine, CaCO3, adipose, and water samples. The dose (air kerma) was 14 mGy for all studies. The low and high energy CT data were simulated at 80 kVp and 140 kVp for DSCT, and in 20–58 keV and 59–120 keV energy ranges for PCCT, respectively. The experiments used Somatom Flash DSCT system and PCCT system based on photon counting CdZnTe detector with 2  ×  256 pixel configuration and 1  ×  1 mm2 pixels size. In simulated general CT images, PCCT provided higher contrast-to-noise ratio (CNR) than DSCT with 0.4/0.8 mm Sn filters. The PCCT with K-edge filter provided higher CNR than the PCCT with a Cu filter, and DSCT with 0.4 mm Sn filter provided higher CNR than the DSCT with a 0.8 mm Sn filter. In simulated DE subtracted images, CNR of the DSCT was comparable to the PCCT with a Cu filter. However, DE PCCT with Ho a K-edge filter provided 30–40% higher CNR than the DE DSCT with 0.4/0.8 mm Sn filters. The experimental PCCT provided higher CNR in general imaging compared to the DSCT. In experimental DE subtracted images, the DSCT provided higher CNR than the PCCT with a Cu filter. However, experimental CNR with DE PCCT with K-edge filter was 15% higher than in DE DSCT, which is less than 30–40% increase predicted by the simulation study. It is concluded that ideal PCCT can provide substantial advantages over

  5. Temporal resolution and motion artifacts in single-source and dual-source cardiac CT

    Schoendube, Harald; Allmendinger, Thomas; Stierstorfer, Karl; Bruder, Herbert; Flohr, Thomas [Siemens AG, Healthcare Sector, Computed Tomography, 91301 Forchheim (Germany)

    2013-03-15

    Purpose: The temporal resolution of a given image in cardiac computed tomography (CT) has so far mostly been determined from the amount of CT data employed for the reconstruction of that image. The purpose of this paper is to examine the applicability of such measures to the newly introduced modality of dual-source CT as well as to methods aiming to provide improved temporal resolution by means of an advanced image reconstruction algorithm. Methods: To provide a solid base for the examinations described in this paper, an extensive review of temporal resolution in conventional single-source CT is given first. Two different measures for assessing temporal resolution with respect to the amount of data involved are introduced, namely, either taking the full width at half maximum of the respective data weighting function (FWHM-TR) or the total width of the weighting function (total TR) as a base of the assessment. Image reconstruction using both a direct fan-beam filtered backprojection with Parker weighting as well as using a parallel-beam rebinning step are considered. The theory of assessing temporal resolution by means of the data involved is then extended to dual-source CT. Finally, three different advanced iterative reconstruction methods that all use the same input data are compared with respect to the resulting motion artifact level. For brevity and simplicity, the examinations are limited to two-dimensional data acquisition and reconstruction. However, all results and conclusions presented in this paper are also directly applicable to both circular and helical cone-beam CT. Results: While the concept of total TR can directly be applied to dual-source CT, the definition of the FWHM of a weighting function needs to be slightly extended to be applicable to this modality. The three different advanced iterative reconstruction methods examined in this paper result in significantly different images with respect to their motion artifact level, despite exactly the same

  6. Free Open Source Software and Dual-Use: Loophole or Dissent?

    Foutel, Nathalie

    2011-01-01

    The Free Open Source Software (FOSS) seem far from the military field but in some cases, some technologies normally used for civilian purposes may have military applications. These products and technologies are called dual-use. Can we manage to combine FOSS and dual-use products? On one hand, we have to admit that this kind of association exists - dual-use software can be FOSS and many examples demonstrate this duality - but on the other hand, dual-use software available under free licenses l...

  7. The study on dual-energy lung perfusion imaging in the diagnosis of pulmonary embolism using dual-source CT

    Objective: To explore the diagnostic values of dual energy lung perfusion in the diagnosis of pulmonary embolism by using dual-source CT (DSCT). Methods: Thirty patients with clinically suspected pulmonary embolism underwent dual-energy scanning with dual-source CT. The scanned data were integrated into three groups including 140, 80 kV and coefficient of 0.3. According to the CT pulmonary angiography (CTPA) of the fusion data, the patients were divided into pulmonary embolism group and normal group. The thin-slice reconstruction of data was analyzed using dual-energy perfusion imaging analysis software. The lung field was divided into upper, middle and lower part to make quantitative analysis of lung tissue perfusion. Paired t-tests were used in the normal patients to compare bilateral lungs, and, independent samples t-tests were applied to compare the embolism group and normal group, while minimum intensity projection images (MinIP) were utilized in the assessment of lung ventilation. Results: Dual energy CT showed symmetrical homogeneous perfusion in 16 normal cases, without significant perfusion defects. Quantitative analysis showed that left and right lung perfusion were (27±7) and (28±8) HU respectively, and no significant difference was found between the two sides (t=-1.73, P>0.05). Perfusion of the left upper, middle and lower lung was (23±6), (24±6), and (28±8) HU respectively, while the perfusion of right upper, middle and lower lung was (26±8), (27±8), and (28±9) HU respectively, showing no statistical significant difference between the two sides (t=-1.91, -1.96, -1.73, P>0.05). Angiography of pulmonary embolism group (14 cases) showed filling defects in the pulmonary trunk, segments and sub-segments. Pulmonary perfusion imaging showed low perfusion or defects in lung field that dominated by embolic vessels. Quantitative analysis showed that the perfusion of the whole lung and the middle and lower lung were (22±5), (22±8), and (21±8) HU in the

  8. Dual Z-Source Inverter With Three-Level Reduced Common-Mode Switching

    Gao, Feng; Loh, Poh Chiang; Blaabjerg, Frede;

    2007-01-01

    This paper presents the design of a dual Z-source inverter that can be used with either a single dc source or two isolated dc sources. Unlike traditional inverters, the integration of a properly designed Z-source network and semiconductor switches to the proposed dual inverter allows buck......-boost power conversion to be performed over a wide modulation range, with three-level output waveforms generated. The connection of an additional transformer to the inverter ac output also allows all generic wye-or delta-connected loads with three-wire or four-wire configuration to be supplied by the inverter....... Modulationwise, the dual inverter can be controlled using a carefully designed carrier-based pulsewidth-modulation (PWM) scheme that will always ensure balanced voltage boosting of the Z-source network while simultaneously achieving reduced common-mode switching. Because of the omission of dead-time delays in...

  9. Pancreatic dual-source dual-energy CT: Is it time to discard unenhanced imaging?

    Aim: To compare pancreatic virtual unenhanced (VUE) and true unenhanced (TUE) images and to calculate the potential dose reduction by omitting the conventional unenhanced scan. Materials and methods: Fifty-one patients with known or suspected pancreatic masses underwent contrast-enhanced computed-tomography (CT) during unenhanced and portal venous phases acquired in single-energy (SE) mode, and pancreatic parenchymal phase acquired in dual-energy (DE) mode. The image quality (IQ) and image noise (IN) of TUE and VUE images were evaluated. The effective dose of a combined DE/SE dual-phase protocol was compared with that of a theoretical standard SE triple-phase protocol. The results were tested for statistical significance using the Cohen’s k, the Wilcoxon’s signed rank test, and the paired t-test; p-values of less than 0.05 were considered significant. Results: Mean TUE and VUE IQ were 1.5 ± 0.6 and 1.6 ± 0.6 (k = 0.891), with no significant difference (p > 0.05). Mean TUE and VUE IN were 12.3 ± 1.6 and 10.3 ± 1.5 HU, and resulted significantly different (p < 0.001). Mean effective doses for a combined DE/SE dual-phase protocol and SE triple-phase protocol were 8.9 ± 2.4 mSv (range 4.8–16.2 mSv) and 12.1 ± 3.1 mSv (range 6.4–21.1 mSv). The calculated mean dose reduction achievable by omitting the unenhanced scan was 26.7 ± 9.7% (range 10–46.1; p < 0.001). Conclusion: VUE images are feasible for pancreatic abdominal CT. A combined DE/SE dual-phase protocol permits a significant reduction in dose exposure to patients.

  10. Dual-step prospective ECG-triggered 128-slice dual-source CT for evaluation of coronary arteries and cardiac function without heart rate control: a technical note

    To describe prospective ECG-triggered dual-source CT dual-step pulsing (pECGdualstep) for evaluation of coronary arteries and cardiac function. Fifty-one consecutive patients pre- or post-cardiovascular surgery were examined with adaptive sequential tube current modulated (pECGdual-step) 128-slice dual-source CT without heart rate control (main padding window: 40% RR interval >65 bpm/70% RR interval dual-step128-slice DSCT is feasible for the evaluation of coronary arteries and cardiac function without heart rate control in patients in stable sinus rhythm at a low radiation dose. (orig.)

  11. Dual sourcing : with arbitrary stochastic demand and stochastic lead times

    Schimpel, Ulrich

    2010-01-01

    Companies with high-performing supply chains enjoy essential competitive ad- vantages. However, supply chain management faces an environment of rising risk that endangers these competitive advantages. One of the reasons is to outsource parts of their business. This bears the risk of significantly increased lead times and lead time variability. It is the impact of lead time variability on inventory management that is the central aspect of this book. It describes a mathematical model for dual s...

  12. Dose levels at coronary CT angiography - a comparison of Dual Energy-, Dual Source- and 16-slice CT

    Kerl, J.M.; Bauer, Ralf W.; Maurer, Tobias B.; Aschenbach, Rene; Korkusuz, Huedayi; Lehnert, Thomas; Deseive, Simon; Vogl, Thomas J. [Johann Wolfgang Goethe-University, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany); HELIOS Clinics Erfurt, Department of Diagnostic and Interventional Radiology and Neuroradiology, Erfurt (Germany); Ackermann, Hanns [Johann Wolfgang Goethe-University, Department of Biomathematics, Frankfurt (Germany); HELIOS Clinics Erfurt, Department of Diagnostic and Interventional Radiology and Neuroradiology, Erfurt (Germany)

    2011-03-15

    To compare the dose estimates and image quality of Dual Energy CT (DECT), Dual Source CT (DSCT) and 16-slice CT for coronary CT angiography (cCTA). Sixty-eight patients were examined with 16 - slice MDCT (group 1), 68 patients with DSCT (group 2) and 68 patients using DSCT in dual energy mode (DECT group 3). CT dose index volume, dose length product, effective dose, signal-to-noise, and contrast-to-noise ratio were compared. Subjective image quality was rated by two observers, blinded to technique. The mean estimated radiation dose of all patients investigated on a 16 - slice MDCT was 12 {+-} 3.59 mSv, for DSCT in single energy 9.8 {+-} 4.77 mSv and for DECT 4.54 {+-} 1.87 mSv. Dose for CTA was significantly lower in group 3 compared to group 1 and 2. The image noise was significantly lower in Group 2 in comparison to group 1 and group 3. There was no significant difference in diagnostic image quality comparing DECT and DSCT. cCTA shows better dose levels at both DECT and DSCT compared to 16-slice CT. Further, DECT delivers significantly less dose than regular DSCT or single source single energy cCTA while maintaining diagnostic image quality. (orig.)

  13. Novel Hexagonal Dual-Mode Substrate Integrated Waveguide Filter with Source-Load Coupling

    Ziqiang Xu; Gen Zhang; Hong Xia; Meijuan Xu

    2014-01-01

    Hexagonal dual-mode cavity and its application to substrate integrated waveguide (SIW) filter are presented. The hexagonal SIW resonator which can combine flexibility of rectangular cavity and performance of circular cavity is convenient for dual-mode bandpass filters design. By introducing coupling between source and load, the filter not only has good selectivity due to two controllable transmission zeros, but also has a small size by the virtue of its single-cavity structure. A demonstratio...

  14. Application of dual-energy scanning technique with dual-source CT in pulmonary mass lesions

    Objective: To explore the feasibility of DSCT dual-energy technique in pulmonary mass lesions. Methods: A total of 100 patients with pulmonary masses underwent conventional plain CT scan and dual-energy enhanced CT scan. The virtual non-contrast (VNC) images were obtained at post-processing workstation.The mean CT value,enhancement value,signal to noise ratio (SNR), image quality and radiation dose of pulmonary masses were compared between the two scan techniques using F or t test and the detectability of lesions was compared using Wilcoxon test. Results: There was no statistically significant difference among VNC (A) (32.89 ± 12.58) HU,VNC (S) (30.86 ± 9.60) HU and conventional plain images (35.89 ± 9.99) HU in mean CT value of mass (F =2.08, P>0.05). There was statistically significant difference among VNC (A) (3.29 ± 1.45), VNC (S) (3.93 ± 1.49) and conventional plain image (4.61 ± 1.50) in SNR (F =6.01, P<0.05), which of conventional plain scan was higher than that of VNC.The enhancement value of mass in conventional enhanced scan (60.74 ± 13.9) HU and distribution of iodine from VNC (A) (58.26 ± 31.99) HU was no statistically significant difference (t=0.48, P>0.05), but there was a significant difference between conventional enhanced scan (56.51 ± 17.94) HU and distribution of iodine from VNC (S) (52.65 ± 16.78) HU (t=4.45, P<0.05). There was no statistically significant difference among conventional plain scan (4.69 ± 0.06) and VNC (A) (4.60 ± 0.09), VNC (S) (4.61 ±0.11) in image quality at mediastinal window (F=3.014, P>0.05). The appearance, size, internal features of mass (such as necrosis, calcification and cavity) were showed the same in conventional plain scan, VNC (A) and VNC (S). Of 41 patients with hilar mass, 18 patients were found to have lobular and segmental perfusion decrease or defect. Perfusion defect area was found in 59 patients with peripheral lung mass. The radiation dose of dual-energy enhanced scan was lower than that of

  15. Source book for planning nuclear dual-purpose electric/distillation desalination plants

    A source book on nuclear dual-purpose electric/distillation desalination plants was prepared to assist government and other planners in preparing broad evaluations of proposed applications of dual-purpose plants. The document is divided into five major sections. Section 1 presents general discussions relating to the benefits of dual-purpose plants, and spectrum for water-to-power ratios. Section 2 presents information on commercial nuclear plants manufactured by US manufacturers. Section 3 gives information on distillation desalting processes and equipment. Section 4 presents a discussion on feedwater pretreatment and scale control. Section 5 deals with methods for coupling the distillation and electrical generating plants to operate in the dual mode

  16. Truncus arteriosus:Diagnosis with dual-source computed tomography angiography and low radiation dose

    Mustafa; Koplay; Derya; Cimen; Mesut; Sivri; Osman; Güvenc; Derya; Arslan; Alaaddin; Nayman; Bulent; Oran

    2014-01-01

    Truncus arteriosus is an uncommon congenital cardiac abnormality which is characterized by a single arterial trunk origin from the heart that supplies both the systemic,pulmonary and coronary circulation.We present a preterm newborn female patient with type 2 truncusarteriosus,left superior vena cava and aberrant subclavian artery diagnosed with low dose dual-source cardiac computed tomography(CT).We discuss that low dose dual-source cardiac CT has more advantages than other imaging methods and it is an important modality for assessment of patients with conotruncal anomalies such as truncusarteriosus.

  17. Application of dual-source CT in evaluation of hepatocellular carcinoma after transarterial chemoembolization treatment

    Objective: To assess the diagnostic value of dual-energy dual-source CT in detecting the enhancement of hepatocellular cancer (HCC) after transarterial chemoembolization (TACE) treatment, Methods: Twenty-seven patients with HCC underwent dual-energy dual-source CT including nonenhanced, arterial, portal, and delayed phases scanning after TACE treatment. Arterial phases were acquired with the dual-energy mode for reconstruction of virtual nonenhanced images and color overlay images. DSAs were performed in all these patients. Two blinded and independent readers evaluated the data in 2 reading sessions: standard nonenhanced, arterial phase, portal phase, and delayed phase images were read in session A, and virtual nonenhanced, arterial phase, portal phase, and delayed phase images in session B. Sensitivity and specificity were calculated, with the DSA data set as the reference standard. The sensitivity and specificity were compared with Chi-square test. Results: DSA revealed 63 lesions in 27 patients, and 39 of them had blood supply. Overall sensitivity and specificity were 74.4% (29/39) and 83.3% (20/24) for session A, and 94.9% (37/39), 95.8% (23/24) for session B, respectively. The sensitivity of the two reading sessions was significantly different (χ2=6.303, P2=2.009, P>0.05). Conclusion: Compared with standard dynamic protocols, an arterial dual-energy dual-source CT scan with reconstruction of virtual nonenhanced and color overlay images enables detection of relapse and intrahepatic metastasis of HCC after TACE treatment with higher accuracy. (authors)

  18. Plasma Characteristics Using Superimposed Dual Frequency Inductively Coupled Plasma Source for Next Generation Device Processing.

    Lee, Seung Min; Lee, Chul Hee; Kim, Tae Hyung; Yeom, Geun Young; Kim, Kyong Nam

    2015-11-01

    U-shaped inductively coupled plasma (ICP) source was investigated as a linear plasma source for the next generation roll-to-toll flexible display processing. For the radio frequency power to the source, the dual frequency composed of 13.56 MHz and 2 MHz was used and the effect of dual frequency to the U-shaped ICP source on the plasma density, electron temperature, and plasma uniformity was investigated. As the operating condition, 200 mTorr Ar was used without operating turbo pumps. The use of superimposed dual frequency composed of 13.56 MHz + 2 MHz instead the single frequency of 13.56 MHz increased the plasma density slightly at the same total power. In addition, the addition of 2 MHz rf power to 0.4 kW while maintaining 1 kW 13.56 MHz rf power not only decreased electron temperature but also improved both the plasma uniformity and the process uniformity measured by photoresist etching. Therefore, by using the dual frequency to the U-shaped ICP source, not only the plasma density but also plasma uniformity could be improved in addition to the decrease of possible damage to the substrate. PMID:26726573

  19. Calcium scoring using 64-slice MDCT, dual source CT and EBT : a comparative phantom study

    Groen, Jaap M.; Greuter, Marcel J. W.; Vliegenthart, R.; Suess, C.; Schmidt, B.; Zijlstra, F.; Oudkerk, M.

    2008-01-01

    Purpose Assessment of calcium scoring (Ca-scoring) on a 64-slice multi-detector computed tomography (MDCT) scanner, a dual-source computed tomography (DSCT) scanner and an electron beam tomography (EBT) scanner with a moving cardiac phantom as a function of heart rate, slice thickness and calcium de

  20. Design of triode extraction system for a dual hollow cathode ion source

    WANG Jing-Hui; ZHU Kun; ZHAO Wei-Jiang; LIU Ke-Xin

    2011-01-01

    A triode extraction system is designed for a dual hollow cathode ion source being developed at the Institute of Heavy Ion Physics,Peking University.Basic parameters of the plasma are selected after examining the operation principle of the ion source,then the triode extraction system is designed and optimized by using software PBGUNS (for Particle Beam GUN Simulations).The physical design of the system is given in this paper.

  1. Mitigating Supply Risk: Dual Sourcing or Process Improvement?

    Yimin Wang; Wendell Gilland; Brian Tomlin

    2010-01-01

    Surveys suggest that supply chain risk is a growing issue for executives and that supplier reliability is of particular concern. A common mitigation strategy is for the buying firm to expend effort improving the reliability of its supply base. We explore a model in which a firm can source from multiple suppliers and/or exert effort to improve supplier reliability. For both random capacity and random yield types of supply uncertainty, we propose a model of process improvement in which improvem...

  2. Dual color x rays from Thomson or Compton sources

    Petrillo, V.; Bacci, A.; Curatolo, C.; Ferrario, M.; Gatti, G.; Maroli, C.; Rau, J. V.; Ronsivalle, C.; Serafini, L.; Vaccarezza, C.; Venturelli, M.

    2014-02-01

    We analyze the possibility of producing two-color x or γ radiation by Thomson/Compton backscattering between a high intensity laser pulse and a two-energy level electron beam, constituted by a couple of beamlets separated in time and/or energy obtained by a photoinjector with comb laser techniques and linac velocity bunching. The parameters of the Thomson source at SPARC_LAB have been simulated, proposing a set of realistic experiments.

  3. Adenosine in exercise adaptation.

    Simpson, R E; Phillis, J. W.

    1992-01-01

    By influencing the regulation of the mechanisms of angiogenesis, erythropoietin production, blood flow, myocardial glucose uptake, glycogenolysis, systolic blood pressure, respiration, plasma norepinephrine and epinephrine levels, adenosine may exert a significant effect on the body's adaptation response to exercise. However, adenosine's possible influence over the vasodilatory response to exercise in skeletal muscle is controversial and more research is required to resolve this issue. Variou...

  4. Dual versus single source models for estimating surface temperature of African savannah

    C. Huntingford

    2000-01-01

    Full Text Available Predictions of average surface temperature of a sparsely vegetated West-African savannah by both single and dual source models of surface energy partitioning are compared. Within the single source model, the ``excess resistance' to heat transfer away from the canopy (compared to momentum absorption is characterised by parameter kB-1, where k is the von Kármán constant and B is the Stanton number. Two values of this parameter are used; first kB-1 = 2 (a value often used within surface energy balance models but primarily applicable to permeable vegetation types and then 12.4 (a value applicable to the savannah in question, which consists more of bluff roughness elements. As expected, the latter parameterisation generates better predictions of surface temperature. To make accurate predictions of surface temperature using a dual source model, then that model’s in-canopy aerodynamic resistance must be increased. Information on this increase is found through direct model intercomparison with the single source model parameterised with kB-1 = 12.4. Keywords: Penman-Monteith equation; Surface temperature; Canopy resistance; Savannah; Dual-Source model

  5. Attenuation-based characterization of coronary atherosclerotic plaque: Comparison of dual source and dual energy CT with single-source CT and histopathology

    Objective: To compare different CT acquisition techniques regarding for attenuation-based characterization of coronary atherosclerotic plaques using histopathology as the standard of reference. Materials and methods: In a post mortem study 17 human hearts were studied with dual-source CT (DSCT) and dual energy CT (DECT) mode on a DSCT as well as with 16-slice single-source CT (SSCT). At autopsy, atherosclerotic lesions were cut at 5 μm sections. Histopathologic classification of the plaques according to the American Heart Association (AHA) criteria was performed by two pathologists. Attenuation values of all plaques were measured in DSCT, DECT and SSCT studies, respectively and classified based on attenuation according to modified AHA criteria. Results: 58 coronary plaques were identified at autopsy. Regardless of the CT technique only 52/58 plaques were found at CT (sensitivity = 89.6%). There was no significant difference between the mean attenuation values of different plaque types between DSCT, DECT, and SSCT: type IV: 11 HU/8 HU/19 HU; type Va: 44 HU/45 HU/52 HU; type Vb: 1088 HU/966 HU/1079 HU). The sensitivity for correct classification varied depending on the plaque type (type II = 0%, type III = 0%, type IV = 43%, type Va = 58%, Vb = 97%). Conclusion: Independent of the used acquisition technique, SSCT, DSCT and DECT show similar results for attenuation-based characterization of atherosclerotic coronary plaques.

  6. Correlation of radiation dose and heart rate in dual-source computed tomography coronary angiography

    Background: Computed tomography coronary angiography (CTCA) has been widely used since the introduction of 64-slice scanners and dual-source CT technology, but the relatively high radiation dose remains a major concern. Purpose: To evaluate the relationship between radiation exposure and heart rate (HR), in dual-source CTCA. Material and Methods: Data from 218 CTCA examinations, performed with a dual-source 64-slices scanner, were statistically evaluated. Effective radiation dose, expressed in mSv, was calculated as the product of the dose-length product (DLP) times a conversion coefficient for the chest (mSv = DLPx0.017). Heart rate range and mean heart rate, expressed in beats per minute (bpm) of each individual during CTCA, were also provided by the system. Statistical analysis of effective dose and heart rate data was performed by using Pearson correlation coefficient and two-sample t-test. Results: Mean HR and effective dose were found to have a borderline positive relationship. Individuals with a mean HR >65 bpm observed to receive a statistically significant higher effective dose as compared to those with a mean HR =65 bpm. Moreover, a strong correlation between effective dose and variability of HR of more than 20 bpm was observed. Conclusion: Dual-source CT scanners are considered to have the capability to provide diagnostic examinations even with high HR and arrhythmias. However, it is desirable to keep the mean heart rate below 65 bpm and heart rate fluctuation less than 20 bpm in order to reduce the radiation exposure

  7. Radiation dose estimates in dual-source computed tomography coronary angiography

    Stolzmann, Paul; Scheffel, Hans; Schertler, Thomas; Frauenfelder, Thomas; Leschka, Sebastian; Husmann, Lars; Marincek, Borut; Alkadhi, Hatem [University Hospital Zurich, Institute of Diagnostic Radiology, Zurich (Switzerland); Flohr, Thomas G. [Siemens Medical Solutions, Forchheim (Germany); Kaufmann, Philipp A. [Cardiovascular Center, Forchheim (Germany)

    2008-03-15

    The purpose of this study was to quantify radiation dose parameters of dual-source CT coronary angiography. Eighty patients underwent contrast-enhanced, retrospectively ECG-gated dual-source CT coronary angiography with heart rate-adapted ECG pulsing using two algorithms: In 40 patients, the tube current was reduced to 20% (A{sub min1}) of the normal tube current (A{sub max}) outside the pulsing window; in 40 patients tube current was reduced to 4% (A{sub min2}) of A{sub max}. Mean CTDI{sub vol} in the A{sub min1} group was 45.1 {+-} 3.6 mGy; the mean CTDI{sub vol} in the A{sub min2} group was 39.1 {+-} 3.2 mGy, with CTDI{sub vol} in the A{sub min2} group being significantly reduced when compared to the A{sub min1} group (P < 0.001). A significant negative correlation was found between CTDI{sub vol} and heart rate in group A{sub min1} (r = -0.82, P < 0.001), whereas no correlation was found between CTDI{sub vol} and heart rate in group A{sub min2} (r = -0.066). Using the conversion coefficient for the chest, dual-source CT coronary angiography resulted in an estimated mean effective dose of 8.8 mSv in the A{sub min1} group and 7.8 mSv in the A{sub min2}. Radiation exposure of dual-source CT coronary angiography using an ECG-pulsing protocol reducing the tube current to 20% significantly decreases with increasing heart rates, despite using wider pulsing windows at higher heart rates. When using a protocol with reduced tube current of 4%, the radiation dose is significantly lower, irrespective of the heart rate. (orig.)

  8. Calcium scoring using 64-slice MDCT, dual source CT and EBT: a comparative phantom study

    Groen, Jaap M.; Greuter, Marcel J. W.; Vliegenthart, R.; Suess, C.; Schmidt, B.; Zijlstra, F.; Oudkerk, M.

    2007-01-01

    Purpose Assessment of calcium scoring (Ca-scoring) on a 64-slice multi-detector computed tomography (MDCT) scanner, a dual-source computed tomography (DSCT) scanner and an electron beam tomography (EBT) scanner with a moving cardiac phantom as a function of heart rate, slice thickness and calcium density. Methods and materials Three artificial arteries with inserted calcifications of different sizes and densities were scanned at rest (0 beats per minute) and at 50–110 beats per minute (bpm) w...

  9. Case report: Intra-atrial course of right coronary artery: Evaluation by dual-source CT

    We report a case of an anomalous course of the right coronary artery (RCA) through the right atrium, which was evaluated using dual-source CT angiography. There have been a few cases described previously in literature, but most of them were found either during surgery or at autopsy. Although this variant is clinically benign, it has significant consequences during interventional procedures or bypass surgery

  10. Adenosine Receptors and Asthma

    Wilson, Constance N; Nadeem, Ahmed; Spina, Domenico; Brown, Rachel; Page, Clive P.; Jamal Mustafa, S.

    2009-01-01

    The pathophysiological processes underlying respiratory diseases like asthma are complex, resulting in an overwhelming choice of potential targets for the novel treatment of this disease. Despite this complexity, asthmatic subjects are uniquely sensitive to a range of substances like adenosine, thought to act indirectly to evoke changes in respiratory mechanics and in the underlying pathology, and thereby to offer novel insights into the pathophysiology of this disease. Adenosine is of partic...

  11. Investigating whether it is optimal to make replenishments simultaneously in dual source model

    Abginehchi, Soheil; Larsen, Christian

    In multiple sourcing, when supplier lead times are stochastic it makes sense to split any replenishment order into several smaller orders to pool lead time risks. In literature it is always assumed these orders are issued simultaneously to the suppliers. Here we let this simultaneousness assumption...... be relaxed. We study a dual source system with non-identical suppliers and model the problem as a semi-Markov decision model, allowing the decision maker the choice whether he will simultaneously issue two orders to both suppliers or he will issue the orders to suppliers at two different times....

  12. Performance analysis of air——water dual source heat pump water heater with heat recovery

    CHEN ZeShao; TAO WenQuan; ZHU YanWen; HU Peng

    2012-01-01

    A new air-water dual source heat pump water heater with heat recovery is proposed.The heat pump system can heat water by using a single air source,a single water source,or air-water dual sources.The water is first pre-heated by waste hot water,then heated by the heat pump.Waste heat is recovered by first preheating the cold water and as water source of the heat pump.According to the correlated formulas of the coefficient of performance of air-source heat pump and water-source heat pump,and the gain coefficient of heat recovery-preheater,the formulas for the coefficient of performance of heat pump in six operating modes are obtained by using the dimensionless correspondence analysis method.The system characteristics of heat absorption and release associated with the heat recovery-preheater are analyzed at different working conditions.The developed approaches can provide reference for the optimization of the operating modes and parameters.The results of analysis and experiments show that the coefficient of performance of the device can reach 4-5.5 in winter,twice as much as air source heat pump water heater.The utilization of waste heat in the proposed system is higher than that in the system which only uses waste water to preheating or as heat source.Thus,the effect of energy saving of the new system is obvious.On the other hand,the dimensionless correspondence analysis method is introduced to performance analysis of the heat pump,which also has theoretical significance and practical value.

  13. Novel hexagonal dual-mode substrate integrated waveguide filter with source-load coupling.

    Xu, Ziqiang; Zhang, Gen; Xia, Hong; Xu, Meijuan

    2014-01-01

    Hexagonal dual-mode cavity and its application to substrate integrated waveguide (SIW) filter are presented. The hexagonal SIW resonator which can combine flexibility of rectangular cavity and performance of circular cavity is convenient for dual-mode bandpass filters design. By introducing coupling between source and load, the filter not only has good selectivity due to two controllable transmission zeros, but also has a small size by the virtue of its single-cavity structure. A demonstration filter with a center frequency of 10 GHz and a 3 dB fractional bandwidth of 4% is designed and fabricated to validate the proposed structure. Measured results are in good agreement with simulated ones. PMID:24895669

  14. [Review of dual stable isotope technique for nitrate source identification in surface- and groundwater in China].

    Xu, Zhi-Wei; Zhang, Xin-Yu; Yu, Gui-Rui; Sun, Xiao-Min; Wen, Xue-Fa

    2014-08-01

    Water nitrate (NO3-) contamination is a world-wide environmental problem under the effects of intensive human activities. Sources identification of NO3- contamination in water is important for better management of water quality. Dual stable isotope data of nitrate nitrogen (delta15N) and nitrate oxygen (delta18O) combined with other stable isotopes and chemical analysis data have been frequently used to identify NO3- sources, differentiate percentage of the different NO3- sources and assess the nitrification/denitrification processes of surface water, groundwater and precipitation, respectively. This review summarized the analysis technique of nitrate delta15N and delta18O in domestic and abroad, assessed typical values of delta15N, delta18O from different NO3- sources and evaluated the progress in application of dual stable isotope of delta15N and delta18O technique to trace NO3- sources in surface- and ground-water. Both ion exchange-AgNO3 and bacteria denitrifying methods have been successfully used in tracing water nitrate sources nationwide. The comprehensive metadata analysis of nitrate sources showed that the delta15N values of sewage and manure, soil, precipitation, fertilizer ranged from 3 per thousand to 17 per thousand, 3 per thousand to 8 per thousand, - 9 per thousand to 9 per thousand, -2 per thousand to 4 per thousand, respectively. And the delta15N values of ammonium fertilizer ranged from - 4 per thousand to 2 per thousand. According to the stable isotope technique, sewage and manure were identified as the major nitrate sources of surface- and ground-water in China. This indicated that municipal sewage and aquaculture exerted serious influence on the nitrate pollution of surface water. In the future, long-term monitoring, dual stable isotope fingerprinting and hydro-chemical analysis should be applied together to quantitatively differentiate contribution of nitrate sources, and to assess seasonal dynamic of nitrate sources. It will provide useful

  15. A Metabolic Immune Checkpoint: Adenosine in Tumor Microenvironment

    Ohta, Akio

    2016-01-01

    Within tumors, some areas are less oxygenated than others. Since their home ground is under chronic hypoxia, tumor cells adapt to this condition by activating aerobic glycolysis; however, this hypoxic environment is very harsh for incoming immune cells. Deprivation of oxygen limits availability of energy sources and induces accumulation of extracellular adenosine in tumors. Extracellular adenosine, upon binding with adenosine receptors on the surface of various immune cells, suppresses pro-inflammatory activities. In addition, signaling through adenosine receptors upregulates a number of anti-inflammatory molecules and immunoregulatory cells, leading to the establishment of a long-lasting immunosuppressive environment. Thus, due to hypoxia and adenosine, tumors can discourage antitumor immune responses no matter how the response was induced, whether it was spontaneous or artificially introduced with a therapeutic intention. Preclinical studies have shown the significance of adenosine in tumor survival strategy by demonstrating tumor regression after inactivation of adenosine receptors, inhibition of adenosine-producing enzymes, or reversal of tissue hypoxia. These promising results indicate a potential use of the inhibitors of the hypoxia–adenosine pathway for cancer immunotherapy. PMID:27066002

  16. An adaptable dual species effusive source and Zeeman slower design demonstrated with Rb and Li

    Bowden, William; Gunton, Will; Semczuk, Mariusz; Dare, Kahan; Madison, Kirk W.

    2016-04-01

    We present a dual-species effusive source and Zeeman slower designed to produce slow atomic beams of two elements with a large mass difference and with very different oven temperature requirements. We demonstrate this design for the case of 6Li and 85Rb and achieve magneto-optical trap (MOT) loading rates equivalent to that reported in prior work on dual species (Rb+Li) Zeeman slowers operating at the same oven temperatures. Key design choices, including thermally separating the effusive sources and using a segmented coil design to enable computer control of the magnetic field profile, ensure that the apparatus can be easily modified to slow other atomic species. By performing the final slowing using the quadrupole magnetic field of the MOT, we are able to shorten our Zeeman slower length making for a more compact system without compromising performance. We outline the construction and analyze the emission properties of our effusive sources. We also verify the performance of the source and slower, and we observe sequential loading rates of 12 × 108 atoms/s for a Rb oven temperature of 140 °C and 1.1 × 108 atoms/s for a Li reservoir at 460 °C, corresponding to reservoir lifetimes for continuous operation of 10 and 4 years, respectively.

  17. A new compact self-coherent high power microwave source based on dual beams

    Yan, Xiaolu, E-mail: yanxl-dut@163.com; Zhang, Xiaoping; Li, Yangmei; Qi, Zumin; Dang, Fangchao [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

    2015-05-15

    In this paper, a compact self-coherent high power microwave source based on dual beams is presented. It consists of a two-cavity triaxial klystron amplifier (TKA) (noted as the outer sub-source below) and a multiwave Cerenkov generators (noted as the inner sub-source) inserted in the TKA's inner conductor. These two sub-sources share a common cathode and the magnetic field. The injected signals to the outer sub-source are leakage microwaves from the inner sub-source through the anode-cathode gap (A-K gap). Particle-in-cell simulation shows that when the diode voltage is 687 kV and the axial magnetic field is 0.8 T, two microwaves with power of 1.02 GW and 2.65 GW and the same frequency of 9.72 GHz are generated in the inner and the outer sub-source, respectively; the corresponding power efficiencies are 24% and 31%. Two sub-sources reach the phase locking at 23 ns with a phase difference fluctuation within ±3°. The fast and stable phase locking in the voltage ranging from 665 kV to 709 kV further suggests that the proposed source is promising for coherent power combination and to export a higher power of combined microwaves.

  18. Supercontinuum optimization for dual-soliton based light sources using genetic algorithms in a Grid platform

    Arteaga-Sierra, F R; Torres-Gómez, I; Torres-Cisneros, M; Moltó, G; Ferrando, A

    2014-01-01

    We present a numerical strategy to design fiber based dual pulse light sources exhibiting two predefined spectral peaks in the anomalous group velocity dispersion regime. The frequency conversion is based on the soliton fission and soliton self-frequency shift occurring during supercontinuum generation. The optimization process is carried out by a genetic algorithm that provides the optimum input pulse parameters: wavelength, temporal width and peak power. This algorithm is implemented in a Grid platform in order to take advantage of distributed computing. These results are useful for optical coherence tomography applications where bell-shaped pulses located in the second near-infrared window are needed.

  19. Dual-etalon cavity ring-down frequency-comb spectroscopy with broad band light source

    Chandler, David W; Strecker, Kevin E

    2014-04-01

    In an embodiment, a dual-etalon cavity-ring-down frequency-comb spectrometer system is described. A broad band light source is split into two beams. One beam travels through a first etalon and a sample under test, while the other beam travels through a second etalon, and the two beams are recombined onto a single detector. If the free spectral ranges ("FSR") of the two etalons are not identical, the interference pattern at the detector will consist of a series of beat frequencies. By monitoring these beat frequencies, optical frequencies where light is absorbed may be determined.

  20. Preliminary experimental investigation of a complex dual-band high power microwave source

    Zhang, Xiaoping, E-mail: zhangxiaoping@nudt.edu.cn; Li, Yangmei; Li, Zhiqiang; Zhong, Huihuang; Qian, Baoliang [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

    2015-10-15

    In order to promote the power conversion efficiency of a magnetically insulated transmission line oscillator (MILO) and obtain microwaves in dual bands, an axially extracted C-band virtual cathode oscillator (VCO) with multiple resonant cavities is introduced to partially utilize the load current of an S-band MILO. The formed novel dual-band high power microwave source called MILO and VCO is investigated with simulation and experimentally. A dual-band radiation antenna is designed to effectively radiate microwaves generated by the MILO and the VCO, respectively, while avoiding them being influenced by the microwave reflection and diffraction. The preliminary experimental results measured by the dual-band diagnostic system show that both the MILO and the VCO operate normally under repeated shots. A microwave of 2.1 GHz, 1.70 GW is generated from the MILO and a 0.37 GW microwave at frequencies of 4.1 GHz and 3.8 GHz is generated from the VCO under the condition of about 440 kV and 35 kA. Compared with a single MILO (10.6%), a MILO and VCO achieves higher total power and efficiency (13.4%) in both S and C bands, indicating that the load current of the MILO partially couples into the beam-wave interaction in the VCO and then contributes to the output microwaves. However, more works are needed regarding the spectrum purification of the VCO and promotion of the output power of both the MILO and the VCO.

  1. Preliminary experimental investigation of a complex dual-band high power microwave source

    In order to promote the power conversion efficiency of a magnetically insulated transmission line oscillator (MILO) and obtain microwaves in dual bands, an axially extracted C-band virtual cathode oscillator (VCO) with multiple resonant cavities is introduced to partially utilize the load current of an S-band MILO. The formed novel dual-band high power microwave source called MILO and VCO is investigated with simulation and experimentally. A dual-band radiation antenna is designed to effectively radiate microwaves generated by the MILO and the VCO, respectively, while avoiding them being influenced by the microwave reflection and diffraction. The preliminary experimental results measured by the dual-band diagnostic system show that both the MILO and the VCO operate normally under repeated shots. A microwave of 2.1 GHz, 1.70 GW is generated from the MILO and a 0.37 GW microwave at frequencies of 4.1 GHz and 3.8 GHz is generated from the VCO under the condition of about 440 kV and 35 kA. Compared with a single MILO (10.6%), a MILO and VCO achieves higher total power and efficiency (13.4%) in both S and C bands, indicating that the load current of the MILO partially couples into the beam-wave interaction in the VCO and then contributes to the output microwaves. However, more works are needed regarding the spectrum purification of the VCO and promotion of the output power of both the MILO and the VCO

  2. Preliminary experimental investigation of a complex dual-band high power microwave source

    Zhang, Xiaoping; Li, Yangmei; Li, Zhiqiang; Zhong, Huihuang; Qian, Baoliang

    2015-10-01

    In order to promote the power conversion efficiency of a magnetically insulated transmission line oscillator (MILO) and obtain microwaves in dual bands, an axially extracted C-band virtual cathode oscillator (VCO) with multiple resonant cavities is introduced to partially utilize the load current of an S-band MILO. The formed novel dual-band high power microwave source called MILO and VCO is investigated with simulation and experimentally. A dual-band radiation antenna is designed to effectively radiate microwaves generated by the MILO and the VCO, respectively, while avoiding them being influenced by the microwave reflection and diffraction. The preliminary experimental results measured by the dual-band diagnostic system show that both the MILO and the VCO operate normally under repeated shots. A microwave of 2.1 GHz, 1.70 GW is generated from the MILO and a 0.37 GW microwave at frequencies of 4.1 GHz and 3.8 GHz is generated from the VCO under the condition of about 440 kV and 35 kA. Compared with a single MILO (10.6%), a MILO and VCO achieves higher total power and efficiency (13.4%) in both S and C bands, indicating that the load current of the MILO partially couples into the beam-wave interaction in the VCO and then contributes to the output microwaves. However, more works are needed regarding the spectrum purification of the VCO and promotion of the output power of both the MILO and the VCO.

  3. Virtual Monochromatic Images from Dual-Energy Multidetector CT: Variance in CT Numbers from the Same Lesion between Single-Source Projection-based and Dual-Source Image-based Implementations.

    Mileto, Achille; Barina, Andrew; Marin, Daniele; Stinnett, Sandra S; Roy Choudhury, Kingshuk; Wilson, Joshua M; Nelson, Rendon C

    2016-04-01

    Purpose To determine the variance in virtual monochromatic computed tomography (CT) numbers from the same lesion, comparing the two clinically available dual-energy multidetector CT hardware implementations (single-source projection-based and dual-source image-based), in a phantom-based simulated abdominal environment. Materials and Methods This phantom-based study was exempt from institutional review board oversight. Polyethylene terephthalate spheres (15 and 18 mm) with two iodine-to-saline dilutions (0.8 and 1.2 mg of iodine per millilliter) were serially suspended in a cylindrical polypropylene bottle filled with diluted iodinated contrast material. The bottle was placed into a 36-cm-wide torso-shaped water phantom simulating the abdomen of a medium-sized patient. Dual-energy (80/140 kVp) and single-energy (100 and 120 kVp) scans were obtained with single-source and dual-source multidetector CT implementations. Virtual monochromatic images were reconstructed at energy levels of 40-140 keV (in 10-keV increments) in either the projection-space or image-space domain. A multivariate regression analysis approach was used to investigate the effect of energy level, lesion size, lesion iodine content, and implementation type on measured CT numbers. Results There were significant differences in the attenuation values measured in the simulated lesions with the single-source projection-based platform and the dual-source image-based implementation (P platforms respond differently to changes in investigated variables (P virtual monochromatic CT numbers from the same lesion examined with single-source projection-based and dual-source image-based implementations. The magnitude of the variance is a function of the selected energy level and the lesion iodine content. (©) RSNA, 2015 Online supplemental material is available for this article. PMID:26536403

  4. Adenosine and sleep

    Behavioral and biochemical approaches have been used to determine the relative contribution of endogenous adenosine and adenosine receptors to the sleep-wake cycle in the rat. Adenosine concentrations in specific areas of the rat brain were not affected by 24 hours of total sleep deprivation, or by 24 or 48 hours of REM sleep deprivation. In order to assess the effect of REM sleep deprivation on adenosine A1 receptors, 3H-L-PIA binding was measured. The Bmax values for 3H-L-PIA binding to membrane preparations of the cortices and corpus striata from 48 hour REM sleep-deprived animals were increased 14.8% and 23%, respectively. These increases were not maintained following the cessation of sleep deprivation and recovered within 2 hours. The results of a 96 hour REM deprivation experiment were similar to those of the 48 hour REM sleep deprivation experiment. However, these increases were not evident in similar structures taken from stress control animals, and conclusively demonstrated that the changes in 3H-L-PIA binding resulted from REM sleep deprivation and not from stress

  5. Adenosine and sleep

    Yanik, G.M. Jr.

    1987-01-01

    Behavioral and biochemical approaches have been used to determine the relative contribution of endogenous adenosine and adenosine receptors to the sleep-wake cycle in the rat. Adenosine concentrations in specific areas of the rat brain were not affected by 24 hours of total sleep deprivation, or by 24 or 48 hours of REM sleep deprivation. In order to assess the effect of REM sleep deprivation on adenosine A/sub 1/ receptors, /sup 3/H-L-PIA binding was measured. The Bmax values for /sup 3/H-L-PIA binding to membrane preparations of the cortices and corpus striata from 48 hour REM sleep-deprived animals were increased 14.8% and 23%, respectively. These increases were not maintained following the cessation of sleep deprivation and recovered within 2 hours. The results of a 96 hour REM deprivation experiment were similar to those of the 48 hour REM sleep deprivation experiment. However, these increases were not evident in similar structures taken from stress control animals, and conclusively demonstrated that the changes in /sup 3/H-L-PIA binding resulted from REM sleep deprivation and not from stress.

  6. The value of low kilovoltage of dual-source CT coronary angiography in overweight patients

    Objective: To investigate the image quality and the radiation dose of dual-source computed tomography coronary angiography by using low kilovoltage combination with low tube current in overweight patients. Methods: Sixty-six patients with body mass index (BMI) 25.0-30.0 kg/m2 and a body weight 0.05). Estimated ED in group B was significantly lower than that in group A [CTDIvol = (42.2±13.8) mGy, ED = (9.5±3.6) mSv in group A vs. CTDIvol = (20.2±6.5) mGy, ED = (4.8±1.7) mSv in group B; each P0.05). A total of 383 coronary artery segments were evaluated in group A and 490 segments in group B. The difference of grading quantity of coronary artery segment was no statistical significant between two groups. Conclusions: 100 kVp combination with ECG-pulsing and CARE Dose 4D of dual-source CTCA was valuable for patients with BMI ranging from 25 to 30 kg/m2 which have a better image quality and low radiation dose. (authors)

  7. Probabilistic conditional reasoning: Disentangling form and content with the dual-source model.

    Singmann, Henrik; Klauer, Karl Christoph; Beller, Sieghard

    2016-08-01

    The present research examines descriptive models of probabilistic conditional reasoning, that is of reasoning from uncertain conditionals with contents about which reasoners have rich background knowledge. According to our dual-source model, two types of information shape such reasoning: knowledge-based information elicited by the contents of the material and content-independent information derived from the form of inferences. Two experiments implemented manipulations that selectively influenced the model parameters for the knowledge-based information, the relative weight given to form-based versus knowledge-based information, and the parameters for the form-based information, validating the psychological interpretation of these parameters. We apply the model to classical suppression effects dissecting them into effects on background knowledge and effects on form-based processes (Exp. 3) and we use it to reanalyse previous studies manipulating reasoning instructions. In a model-comparison exercise, based on data of seven studies, the dual-source model outperformed three Bayesian competitor models. Overall, our results support the view that people make use of background knowledge in line with current Bayesian models, but they also suggest that the form of the conditional argument, irrespective of its content, plays a substantive, yet smaller, role. PMID:27416493

  8. A stochastic inventory management model for a dual sourcing supply chain with disruptions

    Iakovou, Eleftherios; Vlachos, Dimitrios; Xanthopoulos, Anastasios

    2010-03-01

    As companies continue to globalise their operations and outsource significant portion of their value chain activities, they often end up relying heavily on order replenishments from distant suppliers. The explosion in long-distance sourcing is exposing supply chains and shareholder value at ever increasing operational and disruption risks. It is well established, both in academia and in real-world business environments, that resource flexibility is an effective method for hedging against supply chain disruption risks. In this contextual framework, we propose a single period stochastic inventory decision-making model that could be employed for capturing the trade-off between inventory policies and disruption risks for an unreliable dual sourcing supply network for both the capacitated and uncapacitated cases. Through the developed model, we obtain some important managerial insights and evaluate the merit of contingency strategies in managing uncertain supply chains.

  9. Thermodynamic analysis and optimization of a novel dual-evaporator system powered by electrical and solar energy sources

    A novel dual-evaporator system with dual-source (renewable and electrical energies) is proposed to provide negative and positive evaporator temperatures. The system is a combination of the generator–absorber heat exchange (GAX), ejector-expansion transcritical CO2 refrigeration (EETC), Organic Rankin Cycle (ORC) and supercritical CO2 power cycles. The system is analyzed and optimized thermodynamically in detail. It is found that allocating the lower temperatures (−25 to −45 °C) for EETC evaporator and higher temperatures (5–10 °C) for GAX evaporator is more suitable. Detailed exergy analyses reveal that 19.89% and 5.92% of total input exergy, are useful in EETC evaporator and GAX evaporator, respectively. The ejector is found to be the highest source of irreversibility in the system. Moreover, the system performs better than dual-evaporator systems recently reported in literature. - Highlights: • A novel dual-evaporator dual-source system is proposed and analyzed, thermodynamically. • The system provides negative and positive evaporator temperatures, simultaneously. • The proposed refrigeration system energy source is two-fold; electrical and renewable energies

  10. Analysis of dual-source CT coronary angiography of congenital heart disease in children

    Objective: To analyze the image quality of coronary arteries by dual-source computed tomography (DSCT) in children with congenital heart disease (CHD). Methods: Image quality of coronary arteries were scored by two radiologists with an ordinal grading system. Score 3 or 4 was considered to be good image quality and diagnostic. Score differences among 3 groups of various baseline heart rate levels, 3 groups of various age levels and 4 coronary branches were analyzed by using ANOVA. Multiple linear regression analysis was used to test the effects of age, heart rate, tube voltage, tube current, pitch, contrast volume, contrast injection rate on the coronary image scores. Results: A total of 72 consecutive patients were enrolled. 71.2% (205/288) of coronary artery branches was good enough for diagnosis. Image quality of left main coronary artery (LM, score 3.64 ± 0.49), left anterior descending (LAD, score 2.97 ± 0.40), right coronary artery (RCA, score of 2.82 ± 0.70), left circumflex (LCX, score 2.76 ± 0.73) were in a descending order (F=29.00, P1--3 years old (2.81 ± 0.74), >3-14 years old (3.58 ± 0.52) were in an ascending order (F=20.16, P150 bpm (2.81 ± 0.63) were in a descending order (F=16.72, P<0.01). Multiple linearregression analysis demonstrated that multiple impact factors affected image quality of LM, LAD, LCX and RCA. Age(r=0.013, P<0.01)and contrast volume(r=0.292, P<0.01)had positive correlation with LM score. Age(r=0.509, P<0.01) and voltage (r=0.292, P=0.011) had positive correlation with LAD score. Heart rate(r=-0.179, P<0.05) had negative correlation with LAD score. Age (r=0.063, P< 0.01) had negative correlation with LCX score. Age (r=0.486, P<0.01) and voltage (r=0.220, P<0.05) had positive correlation with RCA score. Conclusions: Dual-source CT could clearly shows coronary arteries of children with CHD over the age of 3 or with heart rate less than 100 bpm. Limitations of Dual-source CT coronary angiography for CHD children included young

  11. The ascending aortic image quality and the whole aortic radiation dose of high-pitch dual-source CT angiography

    Liu, Ying; Xu, Jian; Jian LI; Ren, Jing; LIU, HONGTAO; Xu, Junqing; Wei, Mengqi; Hao, Yuewen; Zheng, Minwen

    2013-01-01

    Background Aortic dissection is a lift-threatening medical emergency associated with high rates of morbidity and mortality. The incidence rate of aortic dissection is estimated at 5 to 30 per 1 million people per year. The prompt and correct diagnosis of aortic dissection is critical. This study was to compare the ascending aortic image quality and the whole aortic radiation dose of high-pitch dual-source CT angiography and conventional dual-source CT angiography. Methods A total of 110 conse...

  12. Adenosine and Sleep

    Bjorness, Theresa E.; Greene, Robert W.

    2009-01-01

    Over the last several decades the idea that adenosine (Ado) plays a role in sleep control was postulated due in large part to pharmacological studies that showed the ability of Ado agonists to induce sleep and Ado antagonists to decrease sleep. A second wave of research involving in vitro cellular analytic approaches and subsequently, the use of neurochemical tools such as microdialysis, identified a population of cells within the brainstem and basal forebrain arousal centers, with activity t...

  13. A Dual Source Ion Mobility-Mass Spectrometer for Direct Comparison of ESI and MALDI Collision Cross Section Measurements

    Sundarapandian, Sevugarajan; May, Jody C.; McLean, John A.

    2010-01-01

    In this report, we describe a dual ionization source ion mobility-mass spectrometer (IM-MS) instrument platform for investigations that critically compare ion mobility collision cross section (CCS) measurements obtained from different ionization methods. The instrument incorporates both matrix-assisted laser desorption ionization (MALDI) and nano-electrospray ionization (nESI) sources. The nESI source incorporates a keyhole geometry ion funnel design which facilitates axial ion focusing, accu...

  14. A new debris sensor based on dual excitation sources for online debris monitoring

    Mechanical systems could be severely damaged by loose debris generated through wear processes between contact surfaces. Hence, debris detection is necessary for effective fault diagnosis, life prediction, and prevention of catastrophic failures. This paper presents a new in-line debris sensor for hydraulic systems based on dual excitation sources. The proposed sensor makes magnetic lines more concentrated while at the same time improving magnetic field uniformity. As a result the sensor has higher sensitivity and improved precision. This paper develops the sensor model, discusses sensor structural features, and introduces a measurement method for debris size identification. Finally, experimental verification is presented indicating that that the sensor can effectively detect 81 μm (cube) or larger particles in 12 mm outside diameter (OD) organic glass pipe. (paper)

  15. Integrated nanohole array surface plasmon resonance sensing device using a dual-wavelength source

    In this paper, we demonstrate a compact integrated nanohole array-based surface plasmon resonance sensing device. The unit includes a LED light source, driving circuitry, CCD detector, microfluidic network and computer interface, all assembled from readily available commercial components. A dual-wavelength LED scheme was implemented to increase spectral diversity and isolate intensity variations to be expected in the field. The prototype shows bulk sensitivity of 266 pixel intensity units/RIU and a limit of detection of 6 × 10−4 RIU. Surface binding tests were performed, demonstrating functionality as a surface-based sensing system. This work is particularly relevant for low-cost point-of-care applications, especially those involving multiple tests and field studies. While nanohole arrays have been applied to many sensing applications, and their suitability to device integration is well established, this is the first demonstration of a fully integrated nanohole array-based sensing device.

  16. New normative standards of conditional reasoning and the dual-source model.

    Singmann, Henrik; Klauer, Karl Christoph; Over, David

    2014-01-01

    There has been a major shift in research on human reasoning toward Bayesian and probabilistic approaches, which has been called a new paradigm. The new paradigm sees most everyday and scientific reasoning as taking place in a context of uncertainty, and inference is from uncertain beliefs and not from arbitrary assumptions. In this manuscript we present an empirical test of normative standards in the new paradigm using a novel probabilized conditional reasoning task. Our results indicated that for everyday conditional with at least a weak causal connection between antecedent and consequent only the conditional probability of the consequent given antecedent contributes unique variance to predicting the probability of conditional, but not the probability of the conjunction, nor the probability of the material conditional. Regarding normative accounts of reasoning, we found significant evidence that participants' responses were confidence preserving (i.e., p-valid in the sense of Adams, 1998) for MP inferences, but not for MT inferences. Additionally, only for MP inferences and to a lesser degree for DA inferences did the rate of responses inside the coherence intervals defined by mental probability logic (Pfeifer and Kleiter, 2005, 2010) exceed chance levels. In contrast to the normative accounts, the dual-source model (Klauer et al., 2010) is a descriptive model. It posits that participants integrate their background knowledge (i.e., the type of information primary to the normative approaches) and their subjective probability that a conclusion is seen as warranted based on its logical form. Model fits showed that the dual-source model, which employed participants' responses to a deductive task with abstract contents to estimate the form-based component, provided as good an account of the data as a model that solely used data from the probabilized conditional reasoning task. PMID:24860516

  17. New Normative Standards of Conditional Reasoning and the Dual-Source Model

    Henrik eSingmann

    2014-04-01

    Full Text Available There has been a major shift in research on human reasoning towards Bayesian and probabilistic approaches, which has been called a new paradigm. The new paradigm sees most everyday and scientific reasoning as taking place in a context of uncertainty, and inference is from uncertain beliefs and not from arbitrary assumptions. In this manuscript we present an empirical test of normative standards in the new paradigm using a novel probabilized conditional reasoning task. Our results indicated that for everyday conditional with at least a weak causal connection between antecedent and consequent only the conditional probability of the consequent given antecedent contributes unique variance to predicting the probability of conditional, but not the probability of the conjunction, nor the probability of the material conditional. Regarding normative accounts of reasoning, we found significant evidence that participants' responses were confidence preserving (i.e., p-valid in the sense of Adams, 1998 for MP inferences, but not for MT inferences. Additionally, only for MP inferences and to a lesser degree for DA inferences did the rate of responses inside the coherence intervals defined by mental probability logic (Pfeifer & Kleiter, 2005, 2010 exceed chance levels. In contrast to the normative accounts, the dual-source model (Klauer, Beller, & Hütter, 2010 is a descriptive model. It posits that participants integrate their background knowledge (i.e., the type of information primary to the normative approaches and their subjective probability that a conclusion is seen as warranted based on its logical form. Model fits showed that the dual-source model, which employed participants' responses to a deductive task with abstract contents to estimate the form-based component, provided as good an account of the data as a model that solely used data from the probabilized conditional reasoning task.

  18. Using a dual isotopic approach to trace sources and mixing of sulphate in Changjiang Estuary, China

    Li Siliang, E-mail: lisiliang@vip.skleg.cn [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Liu Congqiang; Patra, Sivaji [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Wang Fushun [Institute of Applied Radiation, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 201800 (China); Wang Baoli; Yue Fujun [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China)

    2011-06-15

    Highlights: > Changjiang Estuary plays an important role in transportation of the water and solute. > The dual isotopic method could be used to understand sulfate biogeochemistry in estuaries. > Mixing processes should be a major factor involved in the distribution of water and sulphate. > Sulphate in the Changjiang River mainly derived from atmospheric deposition, evaporite dissolution and sulphide oxidation. - Abstract: The dual isotopic compositions of dissolved SO{sub 4}{sup 2-} in aquatic systems are commonly used to ascertain SO{sub 4}{sup 2-} sources and possible biogeochemical processes. In this study, the physical parameters, major anions and isotopic compositions of SO{sub 4}{sup 2-} in water samples from Changjiang River (Nanjin) to the East Sea in Changjiang Estuary were determined. The salinity ranged from 0 per mille to 32.3 per mille in the estuary water samples. The Cl{sup -},SO{sub 4}{sup 2-} concentrations and {delta}{sup 18}O-H{sub 2}O values followed the salinity variations from freshwater to seawater, which indicated that mixing processes might be a major factor involved in the distribution of water and solutes. The contents and isotopic compositions of SO{sub 4}{sup 2-} suggested that atmospheric deposition, evaporite dissolution and sulphide oxidation were the major sources of dissolved SO{sub 4}{sup 2-} in the freshwater of Changjiang River. In addition, the mixing model calculated by contents and isotopic compositions of SO{sub 4}{sup 2-} indicated that the mixing of freshwater and sea water was the major factor involved in SO{sub 4}{sup 2-} distribution in Changjiang Estuary. However, slightly elevated {delta}{sup 18}O-SO{sub 4} values were observed in the turbidity maximum zone, which suggested that biological processes might affect the O isotopic compositions of SO{sub 4}{sup 2-} there.

  19. High-pitch dual-source CT coronary angiography with low volumes of contrast medium

    Lembcke, Alexander; Hein, Patrick A.; Knobloch, Gesine; Durmus, Tahir; Hamm, Bernd [Charite - University Medicine Berlin, Department of Radiology, Berlin (Germany); Schwenke, Carsten [SCO:SSiS - Schwenke Consulting, Berlin (Germany); Huppertz, Alexander [Charite - University Medicine Berlin, Department of Radiology, Berlin (Germany); ISI - Imaging Science Institute Charite, Berlin (Germany)

    2014-01-15

    To assess the effect of lower volumes of contrast medium (CM) on image quality in high-pitch dual-source computed tomography coronary angiography (CTCA). One-hundred consecutive patients (body weight 65-85 kg, stable heart rate ≤65 bpm, cardiac index ≥2.5 L/min/m{sup 2}) referred for CTCA were prospectively enrolled. Patients were randomly assigned to one of five groups of different CM volumes (G{sub 30}, 30 mL; G{sub 40}, 40 mL; G{sub 50}, 50 mL; G{sub 60}, 60 mL; G{sub 70}, 70 mL; flow rate 5 mL/s each, iodine content 370 mg/mL). Attenuation within the proximal and distal coronary artery segments was analysed. Mean attenuation for men and women ranged from 345.0 and 399.1 HU in G{sub 30} to 478.2 and 571.8 HU in G{sub 70}. Mean attenuation values were higher in groups with higher CM volumes (P < 0.0001) and higher in women than in men (P < 0.0001). The proportions of segments with attenuation of at least 300 HU in G{sub 30}, G{sub 40}, G{sub 50}, G{sub 60} and G{sub 70} were 89 %, 95 %, 98 %, 98 % and 99 %. CM volume of 30 mL in women and 40 mL in men proved to be sufficient to guarantee attenuation of at least 300 HU. In selected patients high-pitch dual-source CTCA can be performed with CM volumes of 40 mL in men or 30 mL in women. (orig.)

  20. Different cellular sources and different roles of adenosine: A1 receptor-mediated inhibition through astrocytic-driven volume transmission and synapse-restricted A2A receptor-mediated facilitation of plasticity

    Cunha, Rodrigo A.

    2008-01-01

    Adenosine is a prototypical neuromodulator, which mainly controls excitatory transmission through the activation of widespread inhibitory A1 receptors and synaptically located A2A receptors. It was long thought that the predominant A1 receptor-meditated modulation by endogenous adenosine was a homeostatic process intrinsic to the synapse. New studies indicate that endogenous extracellular adenosine is originated as a consequence of the release of gliotransmitters, namely ATP, which sets a glo...

  1. Clinical application of dual-source CT in diagnosis of coronary artery fistulas in children

    Objective: To explore the clinical application of low-dose dual-source CT (DSCT) angiography in diagnosis of coronary artery fistulas (CAF) in children. Methods: A total of 22 patients [mean age (3.2 ± 1.5) yrs,age range 1.2-6.0 yrs; male 12, female 10] with CAF who underwent DSCT angiography under free breathing were retrospectively reviewed. Surgery was performed in 9 patients,and transcatheter closure in 13 patients. The diagnostic accuracy of DSCT was evaluated based on the surgical or conventional cardiac angiography (CCA) findings. The subjective image quality was evaluated on a four-point scale by two radiologists. Radiation dose values were recorded. Interobserver agreement of subjective image quality grading was assessed by using Kappa statistics. Results: All images were diagnosable. The average subjective image quality score was 2.6 ± 0.7. Two radiologists made good agreement (K = 0.75, P<0.05). Twenty-five coronary artery fistulas in all patients were clearly displayed on DSCT images with accuracy of 100%. CAF arose from right coronary artery in 13 (59.1%) cases, from left coronary artery in 8 (36.4%) cases and from dual coronary arteries in 1 (4.5%) case. There were 4 patients associated with coronary artery aneurysms. The mean dose-length product (DLP) was (25 ± 4) mGy · cm resulting in an estimated mean effective radiation dose of (0.25 ± 0.07) mSv. Conclusion: Low-dose DSCT angiography provides accurate and reliable diagnosis for coronary artery fistulas in children. (authors)

  2. Driving Saturn's Magnetospheric Periodicities from the Upper Atmosphere/Ionosphere: Magnetotail Response to Dual Sources

    Jia, X.; Kivelson, M. G.

    2012-12-01

    Despite the high degree of axial symmetry of Saturn's internal magnetic field, rotation-associated periodicities are evident in Saturn's electromagnetic radiation, its magnetic perturbations and its particle populations. Although close to the mean rotation period of the cloud tops, the electromagnetic period drifts slightly over a time scale of years and, at high latitudes, differs in the north and south. The source of the periodicity remains a mystery. As an extension of an earlier model of Saturn's rotational periodicity [Jia et al., 2012, JGR, A04215], the model investigated here places the momentum source in the upper atmosphere/ionosphere with the wind patterns in both hemispheres rotating about the spin axis at different rates typical of the 2005-2006 southern summer for which Cassini data have been extensively analyzed. A source at low altitudes would account for the persistence of phase following solar wind disruption of magnetospheric flow patterns but might not produce appropriate magnetospheric responses. However, using a 3D magnetohydrodynamic simulation in which vortical winds in the ionosphere drive field-aligned currents into the magnetosphere, we show that the dual sources account nearly quantitatively for many measured magnetospheric responses. This paper focuses on the magnetotail where the model is shown to reproduce many well-documented results of data analysis including the features that appear distinctly at each of the two periods and those that appear as a carrier signal with amplitude modulation and phase shifts. In particular, the model accounts for current sheet flapping and modulation of the plasma sheet thickness and for the periodic structure of density enhancements at high latitudes at different periods in the north and the south.

  3. Sources and Transformations of Nitrate from Streams Draining Varying Land Uses: Evidence from Dual Isotope Analysis

    Burns, D. A.; Boyer, E. W.; Elliott, E. M.; Kendall, C.

    2008-12-01

    Dual isotope analysis revealed evidence of varying sources and processes that affect the transport of nitrate (NO3-) in six watersheds of different land uses in New York. Samples from two streams draining forested watersheds indicated that NO3- derived from nitrification was dominant at baseflow. Values of δ18ONO3 were greater than previously measured in forested watersheds in this region, a difference attributed to a new, more accurate sample preparation method. A watershed dominated by suburban land use, but with all waste water discharged outside the watershed had three δ18ONO3 values > 25‰ indicating a large direct contribution of atmospheric NO3- transported to the stream during some high flow periods. Two watersheds with large proportions of agricultural land use had many samples with δ15NNO3 > 9‰ suggesting a waste source consistent with direct application of manure to fields associated with dairy farming practices in the region. These data showed a linear seasonal pattern with a δ15NNO3:δ18ONO3 close to 1:2 consistent with seasonally-varying denitrification that peaked in late summer to early fall with the warmest temperatures and lowest streamflow of the year. The large annual range of δ18ONO3 (~ 10‰) in these streams suggests a large fractionation associated with denitrification, indicative of a dominance of denitrification outside of the stream environment. Mixing of two or more NO3- sources may also have affected the patterns observed in these two agricultural streams. At a larger basin scale in a mixed land use watershed that represented the average proportions of land uses in this study, none of the source and process patterns observed in the small streams were evident. These results emphasize that observations at small to medium size watersheds of a few to several hundred km2 may be necessary to adequately quantify the relative roles of various NO3- transport and process patterns that contribute to streamflow in large basins.

  4. Identifying diffused nitrate sources in a stream in an agricultural field using a dual isotopic approach

    Nitrate (NO3−) pollution is a severe problem in aquatic systems in Taihu Lake Basin in China. A dual isotope approach (δ15N-NO3− and δ18O-NO3−) was applied to identify diffused NO3− inputs in a stream in an agricultural field at the basin in 2013. The site-specific isotopic characteristics of five NO3− sources (atmospheric deposition, AD; NO3− derived from soil organic matter nitrification, NS; NO3− derived from chemical fertilizer nitrification, NF; groundwater, GW; and manure and sewage, M and S) were identified. NO3− concentrations in the stream during the rainy season [mean ± standard deviation (SD) = 2.5 ± 0.4 mg/L] were lower than those during the dry season (mean ± SD = 4.0 ± 0.5 mg/L), whereas the δ18O-NO3− values during the rainy season (mean ± SD = + 12.3 ± 3.6‰) were higher than those during the dry season (mean ± SD = + 0.9 ± 1.9‰). Both chemical and isotopic characteristics indicated that mixing with atmospheric NO3− resulted in the high δ18O values during the rainy season, whereas NS and M and S were the dominant NO3− sources during the dry season. A Bayesian model was used to determine the contribution of each NO3− source to total stream NO3−. Results showed that reduced N nitrification in soil zones (including soil organic matter and fertilizer) was the main NO3− source throughout the year. M and S contributed more NO3− during the dry season (22.4%) than during the rainy season (17.8%). AD generated substantial amounts of NO3− in May (18.4%), June (29.8%), and July (24.5%). With the assessment of temporal variation of diffused NO3− sources in agricultural field, improved agricultural management practices can be implemented to protect the water resource and avoid further water quality deterioration in Taihu Lake Basin. - Highlights: • The isotopic characteristics of potential NO3− sources were identified. • Mixing with atmospheric NO3− resulted in the high δ18O values in surface water.

  5. Dual diagnosis, as described by those who experience the disorder: using the Internet as a source of data.

    Edward, Karen-Leigh; Robins, Alan

    2012-12-01

    The complexity of providing treatment for people with dual diagnosis is well recognized. For the purpose of this paper, the World Health Organization definition of dual diagnosis was used; that is, a person diagnosed with an alcohol or drug use problem in addition to mental illness. This research explored the personal narratives of those who experience dual diagnosis using the Internet as a data source. An important consideration in using the Internet as a data source was that Web forums can offer a sense of anonymity, allowing people to share very detailed and personal information, and providing a rich source of qualitative data. The results produced five emergent themes: spiralling out of control - again!, getting help and giving support, treating both the addiction and mental illness, having meaning and being active, and being honest with self and others. The results indicate that individuals who experience dual diagnosis are often left to navigate their personal treatment requirements across two diverse systems, and were generally not satisfied with the conflictual advice received across these two systems (i.e. alcohol and other drug and mental health services). This study has produced valuable insights related to consumer-perceived service barriers and enablers. PMID:22830579

  6. Identifying diffused nitrate sources in a stream in an agricultural field using a dual isotopic approach.

    Ding, Jingtao; Xi, Beidou; Gao, Rutai; He, Liansheng; Liu, Hongliang; Dai, Xuanli; Yu, Yijun

    2014-06-15

    Nitrate (NO3(-)) pollution is a severe problem in aquatic systems in Taihu Lake Basin in China. A dual isotope approach (δ(15)NNO3(-) and δ(18)ONO3(-)) was applied to identify diffused NO3(-) inputs in a stream in an agricultural field at the basin in 2013. The site-specific isotopic characteristics of five NO3(-) sources (atmospheric deposition, AD; NO3(-) derived from soil organic matter nitrification, NS; NO3(-) derived from chemical fertilizer nitrification, NF; groundwater, GW; and manure and sewage, M&S) were identified. NO3(-) concentrations in the stream during the rainy season [mean±standard deviation (SD)=2.5±0.4mg/L] were lower than those during the dry season (mean±SD=4.0±0.5mg/L), whereas the δ(18)ONO3(-) values during the rainy season (mean±SD=+12.3±3.6‰) were higher than those during the dry season (mean±SD=+0.9±1.9‰). Both chemical and isotopic characteristics indicated that mixing with atmospheric NO3(-) resulted in the high δ(18)O values during the rainy season, whereas NS and M&S were the dominant NO3(-) sources during the dry season. A Bayesian model was used to determine the contribution of each NO3(-) source to total stream NO3(-). Results showed that reduced N nitrification in soil zones (including soil organic matter and fertilizer) was the main NO3(-) source throughout the year. M&S contributed more NO3(-) during the dry season (22.4%) than during the rainy season (17.8%). AD generated substantial amounts of NO3(-) in May (18.4%), June (29.8%), and July (24.5%). With the assessment of temporal variation of diffused NO3(-) sources in agricultural field, improved agricultural management practices can be implemented to protect the water resource and avoid further water quality deterioration in Taihu Lake Basin. PMID:24686140

  7. Dual-source dual-energy CT angiography with virtual non-enhanced images and iodine map for active gastrointestinal bleeding: Image quality, radiation dose and diagnostic performance

    Sun, Hao, E-mail: sunhao_robert@126.com [Department of Radiology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing 100730 (China); Hou, Xin-Yi, E-mail: hxy_pumc@126.com [Department of Radiology, Beijing Tiantan Hospital, Capital Medical University, Beijing (China); Xue, Hua-Dan, E-mail: bjdanna95@hotmail.com [Department of Radiology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing 100730 (China); Li, Xiao-Guang, E-mail: xglee88@126.com [Department of Radiology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing 100730 (China); Jin, Zheng-Yu, E-mail: zhengyu_jin@126.com [Department of Radiology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing 100730 (China); Qian, Jia-Ming, E-mail: qjiaming57@gmail.com [Department of Gastroenterology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing (China); Yu, Jian-Chun, E-mail: yu-jch@163.com [Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing (China); Zhu, Hua-Dong, E-mail: huadongzhu@hotmail.com [Department of Emergency, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing (China)

    2015-05-15

    Highlights: • GIB is a common gastrointestinal emergency with a high mortality rate. • Detection and localization of GIB source are important for imaging modality. • DSDECTA using a dual-phase scan protocol is clinically feasible. • DSDECTA with VNE and iodine map images can diagnose the active GIB source accurately. • DSDECTA can reduce radiation dose compared with conventional CT examination in GIB. - Abstract: Objectives: To evaluate the clinical feasibility of dual-source dual-energy CT angiography (DSDECTA) with virtual non-enhanced images and iodine map for active gastrointestinal bleeding (GIB). Methods: From June 2010 to December 2012, 112 consecutive patients with clinical signs of active GIB underwent DSDECTA with true non-enhanced (TNE), arterial phase with single-source mode, and portal-venous phase with dual-energy mode (100 kVp/230 mAs and Sn 140 kVp/178 mAs). Virtual non-enhanced CT (VNE) image sets and iodine map were reformatted from ‘Liver VNC’ software. The mean CT number, noise, signal to noise ratio (SNR), image quality and radiation dose were compared between TNE and VNE image sets. Two radiologists, blinded to clinical data, interpreted images from DSDECTA with TNE (protocol 1), and DSDECTA with VNE and iodine map (protocol 2) respectively, with discordant interpretation resolved by consensus. The standards of reference included digital subtraction angiography, endoscopy, surgery, or final pathology reports. Receiver–operating characteristic (ROC) analysis was undertaken and the area under the curve (AUC) calculated for CT protocols 1 and 2, respectively. Results: There was no significant difference in mean CT numbers of all organs (including liver, pancreas, spleen, kidney, abdominal aorta, and psoas muscle) (P > 0.05). Lower noise and higher SNR were found on VNE images than TNE images (P < 0.05). Image quality of VNE was lower than that of TNE without significant difference (P > 0.05). The active GIB source was identified

  8. Dual-source dual-energy CT angiography with virtual non-enhanced images and iodine map for active gastrointestinal bleeding: Image quality, radiation dose and diagnostic performance

    Highlights: • GIB is a common gastrointestinal emergency with a high mortality rate. • Detection and localization of GIB source are important for imaging modality. • DSDECTA using a dual-phase scan protocol is clinically feasible. • DSDECTA with VNE and iodine map images can diagnose the active GIB source accurately. • DSDECTA can reduce radiation dose compared with conventional CT examination in GIB. - Abstract: Objectives: To evaluate the clinical feasibility of dual-source dual-energy CT angiography (DSDECTA) with virtual non-enhanced images and iodine map for active gastrointestinal bleeding (GIB). Methods: From June 2010 to December 2012, 112 consecutive patients with clinical signs of active GIB underwent DSDECTA with true non-enhanced (TNE), arterial phase with single-source mode, and portal-venous phase with dual-energy mode (100 kVp/230 mAs and Sn 140 kVp/178 mAs). Virtual non-enhanced CT (VNE) image sets and iodine map were reformatted from ‘Liver VNC’ software. The mean CT number, noise, signal to noise ratio (SNR), image quality and radiation dose were compared between TNE and VNE image sets. Two radiologists, blinded to clinical data, interpreted images from DSDECTA with TNE (protocol 1), and DSDECTA with VNE and iodine map (protocol 2) respectively, with discordant interpretation resolved by consensus. The standards of reference included digital subtraction angiography, endoscopy, surgery, or final pathology reports. Receiver–operating characteristic (ROC) analysis was undertaken and the area under the curve (AUC) calculated for CT protocols 1 and 2, respectively. Results: There was no significant difference in mean CT numbers of all organs (including liver, pancreas, spleen, kidney, abdominal aorta, and psoas muscle) (P > 0.05). Lower noise and higher SNR were found on VNE images than TNE images (P < 0.05). Image quality of VNE was lower than that of TNE without significant difference (P > 0.05). The active GIB source was identified

  9. Descriptive anatomy of the dominant septal perforators using Dual Source Coronary CT Angiography.

    Brinjikji, Waleed; Harris, Scott R; Froemming, Adam T; Christensen, Kevin N; Lachman, Nirusha; Araoz, Philip A

    2010-01-01

    Although clinical outcomes for septal ablation in treating left ventricular outflow tract obstructions are generally favorable, a variety of complications have been reported including a high incidence of right bundle branch block. These complications may be attributed to anatomic variability of the dominant septal perforator. We used Dual Source CT Coronary Angiography (DS-CTA) to determine the location of the termination point of the dominant septal perforator as well as the distance of the termination point from the mitral annulus in patients undergoing DS-CTA. One-hundred-fourteen DS-CTA scans were retrospectively reviewed by two observers by consensus. The left ventricle was divided into anterior wall, anterioseptum, and inferioseptum. For each segment, the myocardium was divided into three layers (1) right ventricular side, (2) mid portion, and (3) left ventricular side. The zone of termination of the dominant septal perforator was identified as well as the distance of the termination point from the mitral annulus. The dominant septal perforator terminated in the right ventricular side of the anterioseptum in 86 of the 118 visualized terminations (73%) and in the left ventricular anterior wall in 6 visualized terminations (5%). On average, the dominant septal perforator terminated 26.3 +/- 8.6 mm from the mitral annulus. In the majority of cases, the dominant septal perforator terminates in the right ventricular side of anterioseptum. In addition, there is great variability in the distribution of the termination point of the dominant septal perforator from the mitral annulus. PMID:19918876

  10. Dual-source computed tomography in patients with acute chest pain: feasibility and image quality

    Schertler, Thomas; Scheffel, Hans; Frauenfelder, Thomas; Desbiolles, Lotus; Leschka, Sebastian; Stolzmann, Paul; Marincek, Borut; Alkadhi, Hatem [University Hospital Zurich, Department of Medical Radiology, Institute of Diagnostic Radiology, Zurich (Switzerland); Seifert, Burkhardt [University of Zurich, Department of Biostatistics, Zurich (Switzerland); Flohr, Thomas G. [Computed Tomography CTE PA, Siemens Medical Solutions, Forchheim (Germany)

    2007-12-15

    The aim of this study was to determine the feasibility and image quality of dual-source computed tomography angiography (DSCTA) in patients with acute chest pain for the assessment of the lung, thoracic aorta, and for pulmonary and coronary arteries. Sixty consecutive patients (32 female, 28 male, mean age 58.1{+-}16.3 years) with acute chest pain underwent contrast-enhanced electrocardiography-gated DSCTA without prior beta-blocker administration. Vessel attenuation of different thoracic vascular territories was measured, and image quality was semi-quantitatively analyzed by two independent readers. Image quality of the thoracic aorta was diagnostic in all 60 patients, image quality of pulmonary arteries was diagnostic in 59, and image quality of coronary arteries was diagnostic in 58 patients. Pairwise intraindividual comparisons of attenuation values were small and ranged between 1{+-}6 HU comparing right and left coronary artery and 56{+-}9 HU comparing the pulmonary trunk and left ventricle. Mean attenuation was 291{+-}65 HU in the ascending aorta, 334{+-}93 HU in the pulmonary trunk, and 285{+-}66 HU and 268{+-}67 HU in the right and left coronary artery, respectively. DSCTA is feasible and provides diagnostic image quality of the thoracic aorta, pulmonary and coronary arteries in patients with acute chest pain. (orig.)

  11. Cardiac spiral dual-source CT with high pitch: a feasibility study

    Ertel, Dirk; Kalender, Willi A. [University of Erlangen-Nuernberg, Institute of Medical Physics (IMP), Erlangen (Germany); Lell, Michael M. [University of Erlangen-Nuernberg, Department of Radiology, Erlangen (Germany); Harig, Frank [University of Erlangen-Nuernberg, Center of Cardiac Surgery, Erlangen (Germany); Flohr, Thomas; Schmidt, Bernhard [Siemens Healthcare, Forchheim (Germany)

    2009-10-15

    Increase of pitch in spiral CT decreases data acquisition time; dual-source CT (DSCT) systems provide improved temporal resolution. We evaluated the combination of these two features. Measurements were performed using a commercial DSCT system equipped with prototype software allowing pitch factors from p=0.35 to 3.0. We measured slice sensitivity profiles as a function of pitch to assess spatial resolution in the z-direction and the contrast of structures moved periodically to measure temporal resolution. Additionally we derived modulation transfer functions to provide objective parameters; both spatial and temporal resolution were essentially unchanged even at high pitch. CT of the cardiac region of three pigs was performed at p=3.0. In vivo CT images confirmed good image quality; direct comparison with standard low-pitch phase-correlated CT image datasets showed no significant difference. For a normalized z-axis acquisition of 12 cm, the corresponding effective dose value was 2.0 mSv for the high-pitch CT protocol. We conclude that spiral DSCT imaging with a pitch of 3.0 can provide unimpaired image quality with respect to spatial and temporal resolution. Applications to cardiac and thoracic imaging with effective dose below 1 mSv are possible. (orig.)

  12. Comparison of myocardial bridging by dual-source CT with conventional coronary angiography

    The diagnosis of myocardial bridging (MB) is of clinical importance because of the association between MB and compromised coronary flow. The aim of this study was to compare the ability of dual-source computed tomography (DSCT) and conventional coronary angiography (CAG) to detect MB. DSCT were performed in 53 patients and 4-dimensional (D) reconstruction was subsequently performed in 16 patients with MB for double-blinded comparison with the findings of CAG. The diameters at systole and diastole of the coronary segments proximal and distal to the MB and of the tunneled segment were measured. The relationship between the rate of stenosis of the tunneled artery and the ''milking'' effect on 4-D reconstruction was analyzed. Of the 53 patients, CAG and DSCT detected 4 MBs in 3 patients and 21 MBs in 16 patients, respectively (p<0.001). On a per-patient and per-MB basis, significant difference was found between both methods (p=0.001, p<0.001). The 4-D reconstruction showed the milking effect and abnormal blood flow, detecting more MBs than did CAG (p<0.001). The rate of stenosis of the tunneled artery was related to the milking effect on the 4-D reconstruction (r=0.640, p=0.006). In the present study, DSCT detected more MBs than CAG, suggesting its clinical application for diagnosis of this condition. (author)

  13. Multiphase Evaluation of Myocardial Bridging with Dual-Source Computed Tomography

    Long Jiang Zhang; Gui Fen Yang; Chang Sheng Zhou; Wei Huang; Guang Ming Lu (Dept. of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing Univ., Nanjing, Jiangsu Province (China)); Shiroishi, M.S. (Dept. of Radiology, Univ. of Southern California, Keck School of Medicine, Los Angeles, California (United States))

    2009-08-15

    Background: Myocardial bridging (MB), also known as a tunneled artery, is a congenital anomaly that can be readily diagnosed with multidetector-row computed tomography (MDCT). With the advent of dual-source CT (DSCT), it may be feasible to evaluate dynamic changes of MB throughout the entire cardiac cycle. Purpose: To determine the feasibility of dynamic evaluation of MB using DSCT. Material and Methods: Forty-eight patients with MB of the left anterior descending artery diagnosed with multiplanar reconstruction on DSCT were included in this study. Multiphase reconstructions were performed for every subject. Image quality was assessed using a four-point scale (4 excellent; 3 = good; 2 = adequate; 1 = not assessable). Systolic and diastolic images with optimal image quality were selected. Milking effect, defined as the narrowing of the tunneled artery during systole and its dilatation during diastole, was recorded. The stenosis rate of MB was computed. Results: The optimal systolic and diastolic phases occurred between 40% and 70% of the R-R interval (range 20-80% of R-R interval). The image quality scores of all segments in systole and diastole were higher than or equal to 3. Diameter changes of tunneled vessel under MB in systole and diastole indicated milking effect, visualized on conventional coronary angiography (CAG). Average percentage of narrowing of the MB was 36+-14%. Conclusion: High-quality systolic and diastolic images can be acquired using DSCT. Dynamic visualization of MB is possible, and milking effect can be quantified using DSCT

  14. Multiphase Evaluation of Myocardial Bridging with Dual-Source Computed Tomography

    Background: Myocardial bridging (MB), also known as a tunneled artery, is a congenital anomaly that can be readily diagnosed with multidetector-row computed tomography (MDCT). With the advent of dual-source CT (DSCT), it may be feasible to evaluate dynamic changes of MB throughout the entire cardiac cycle. Purpose: To determine the feasibility of dynamic evaluation of MB using DSCT. Material and Methods: Forty-eight patients with MB of the left anterior descending artery diagnosed with multiplanar reconstruction on DSCT were included in this study. Multiphase reconstructions were performed for every subject. Image quality was assessed using a four-point scale (4 excellent; 3 = good; 2 = adequate; 1 = not assessable). Systolic and diastolic images with optimal image quality were selected. Milking effect, defined as the narrowing of the tunneled artery during systole and its dilatation during diastole, was recorded. The stenosis rate of MB was computed. Results: The optimal systolic and diastolic phases occurred between 40% and 70% of the R-R interval (range 20-80% of R-R interval). The image quality scores of all segments in systole and diastole were higher than or equal to 3. Diameter changes of tunneled vessel under MB in systole and diastole indicated milking effect, visualized on conventional coronary angiography (CAG). Average percentage of narrowing of the MB was 36±14%. Conclusion: High-quality systolic and diastolic images can be acquired using DSCT. Dynamic visualization of MB is possible, and milking effect can be quantified using DSCT

  15. Dual-source CT coronary imaging in heart transplant recipients: image quality and optimal reconstruction interval

    Bastarrika, Gorka; Arraiza, Maria; Pueyo, Jesus C. [Clinica Universitaria, Universidad de Navarra, Department of Radiology, Pamplona (Spain); Cecco, Carlo N. de [Universita' di Roma ' ' Sapienza' ' -Ospedale Sant' Andrea, Department of Radiology, Rome (Italy); Ubilla, Matias; Mastrobuoni, Stefano; Rabago, Gregorio [Clinica Universitaria, Universidad de Navarra, Department of Cardiovascular Surgery, Pamplona (Spain)

    2008-09-15

    The image quality and optimal reconstruction interval for coronary arteries in heart transplant recipients undergoing non-invasive dual-source computed tomography (DSCT) coronary angiography was evaluated. Twenty consecutive heart transplant recipients who underwent DSCT coronary angiography were included (19 male, one female; mean age 63.1{+-}10.7 years). Data sets were reconstructed in 5% steps from 30% to 80% of the R-R interval. Two blinded independent observers assessed the image quality of each coronary segments using a five-point scale (from 0 = not evaluative to 4=excellent quality). A total of 289 coronary segments in 20 heart transplant recipients were evaluated. Mean heart rate during the scan was 89.1{+-}10.4 bpm. At the best reconstruction interval, diagnostic image quality (score {>=}2) was obtained in 93.4% of the coronary segments (270/289) with a mean image quality score of 3.04{+-} 0.63. Systolic reconstruction intervals provided better image quality scores than diastolic reconstruction intervals (overall mean quality scores obtained with the systolic and diastolic reconstructions 3.03{+-}1.06 and 2.73{+-}1.11, respectively; P<0.001). Different systolic reconstruction intervals (35%, 40%, 45% of RR interval) did not yield to significant differences in image quality scores for the coronary segments (P=0.74). Reconstructions obtained at the systolic phase of the cardiac cycle allowed excellent diagnostic image quality coronary angiograms in heart transplant recipients undergoing DSCT coronary angiography. (orig.)

  16. Assessment of thoracic aortic elasticity: a preliminary study using electrocardiographically gated dual-source CT

    To gain a new insight into the elastic properties of the thoracic aorta in patients without aortic diseases using electrocardiographically (ECG)-gated dual-source (DS) CT. 56 subjects with no cardiovascular disease, selected from 2,700 people undergoing ECG-gated DSCT examination, were divided into three groups according to their age. CT data were reconstructed in 5% step throughout the RR interval. Diameter and area were measured at the curve of the ascending aorta (AA) and at the same level of the descending aorta (DA). The pulsation and elasticity of the aorta were evaluated. Aortic diameter changes were noted throughout the cardiac cycle. The maximum average diameter was seen at an RR interval of 24.02 ± 4.99% for the AA and 25.63 ± 4.77% for the DA. The minimum was at 93.5 ± 4.04% for the AA and 96.6 ± 4.58% for the DA. There was an age-dependent decrease in elasticity, while different correlation coefficients were found between various age groups and different elastic parameters. The properties of aortic pulsation and wall elasticity could be well shown by ECG-gated DSCT. The new findings regarding segment difference and age relevance were significant and should be taken into account in clinical trials and treatments for the elasticity related cardiovascular diseases. (orig.)

  17. Dual-band optical coherence tomography using a single supercontinuum laser source

    Chen, Siyu; Shu, Xiao; Yi, Ji; Fawzi, Amani; Zhang, Hao F.

    2016-06-01

    We developed a simultaneous visible-light (Vis) and near-infrared (NIR) dual-band optical coherence tomography (OCT) system using a single supercontinuum laser source. The goal was to benchmark our newly developed Vis-OCT against the well-developed NIR-OCT. The Vis-OCT subsystem operated at 91 nm full-width-at-half-maximum (FWHM) bandwidth centered at 566 nm the NIR-OCT subsystem operated at 93 nm FWHM bandwidth centered at 841 nm. The axial resolutions were 1.8 and 4.4 μm in air for the Vis- and NIR-OCT subsystems, respectively. We compared the respective performances, including anatomical imaging, angiography, absolute retinal blood flow measurements, and spectroscopic analysis for retinal blood oxygen saturation (sO2), between the two subsystems in rodents in vivo. While demonstrating minor discrepancies related to operation wavelengths, both subsystems showed comparable performances in the first three tests. However, we were only able to retrieve sO2 using the Vis-OCT subsystem.

  18. Adaptive optics OCT using 1060nm swept source and dual deformable lenses for human retinal imaging

    Jian, Yifan; Lee, Sujin; Cua, Michelle; Miao, Dongkai; Bonora, Stefano; Zawadzki, Robert J.; Sarunic, Marinko V.

    2016-03-01

    Adaptive optics concepts have been applied to the advancement of biological imaging and microscopy. In particular, AO has also been very successfully applied to cellular resolution imaging of the retina, enabling visualization of the characteristic mosaic patterns of the outer retinal layers using flood illumination fundus photography, Scanning Laser Ophthalmoscopy (SLO), and Optical Coherence Tomography (OCT). Despite the high quality of the in vivo images, there has been a limited uptake of AO imaging into the clinical environment. The high resolution afforded by AO comes at the price of limited field of view and specialized equipment. The implementation of a typical adaptive optics imaging system results in a relatively large and complex optical setup. The wavefront measurement is commonly performed using a Hartmann-Shack Wavefront Sensor (HS-WFS) placed at an image plane that is optically conjugated to the eye's pupil. The deformable mirror is also placed at a conjugate plane, relaying the wavefront corrections to the pupil. Due to the sensitivity of the HS-WFS to back-reflections, the imaging system is commonly constructed from spherical mirrors. In this project, we present a novel adaptive optics OCT retinal imaging system with significant potential to overcome many of the barriers to integration with a clinical environment. We describe in detail the implementation of a compact lens based wavefront sensorless adaptive optics (WSAO) 1060nm swept source OCT human retinal imaging system with dual deformable lenses, and present retinal images acquired in vivo from research volunteers.

  19. Prevalence and morphology of coronary artery ectasia with dual-source CT coronary angiography

    To assess the prevalence and morphological characteristics of coronary artery ectasia (CAE) with CT coronary angiography (CTCA) in comparison to conventional catheterangiography (CCA). Dual-source CTCA examinations from 677 consecutive patients (223 women; median age 57 years) were retrospectively evaluated by two blinded observers for the presence of CAE defined as a diameter enlargement ≥1.5 times the diameter of adjacent normal coronary segments. Vessel diameters and contrast attenuation within and proximal to ectatic segments were measured. CCA was used to compare measurements obtained from CTCA with the coronary flow velocity by using the thrombolysis in myocardial infarction (TIMI) frame count. CTCA identified CAE in 20 of 677 (3%) patients. CCA was performed in ten of these patients. CAE diameter measurements with CTCA (10.0 ± 5.4 mm) correlated significantly (r = 0.92, p < 0.001) with the CCA measurements (8.8 ± 4.9 mm), but had higher diameters (levels of agreement: -1.0 to 3.4 mm). Contrast attenuation was significantly lower in the ectatic (343 ± 63 HU) than in the proximal (394 ± 60 HU) segments (p < 0.01). The attenuation difference significantly correlated with the CAE ratio (r = 0.67, p < 0.01) and the TIMI frame count (r = 0.58, p < 0.05). The prevalence of CAE in a population examined by CTCA is around 3%. Contrast attenuation measurements with CTCA correlate well with the flow alterations assessed with CCA. (orig.)

  20. Virtual monochromatic imaging in dual-source and dual-energy CT for visualization of acute ischemic stroke

    Hara, Hidetake; Muraishi, Hiroshi; Matsuzawa, Hiroki; Inoue, Toshiyuki; Nakajima, Yasuo; Satoh, Hitoshi; Abe, Shinji

    2015-07-01

    We have recently developed a phantom that simulates acute ischemic stroke. We attempted to visualize an acute-stage cerebral infarction by using dual-energy Computed tomography (DECT) to obtain virtual monochromatic images of this phantom. Virtual monochromatic images were created by using DECT voltages from 40 to 100 keV in steps of 10 keV and from 60 to 80 keV in steps of 1 keV, under three conditions of the tube voltage with thin (Sn) filters. Calculation of the CNR values allowed us to evaluate the visualization of acute-stage cerebral infarction. The CNR value of a virtual monochromatic image was the highest at 68 keV under 80 kV / Sn 140 kV, at 72 keV under 100 kV / Sn 140 kV, and at 67 keV under 140 kV / 80 kV. The CNR values of virtual monochromatic images at voltages between 65 and 75 keV were significantly higher than those obtained for all other created images. Therefore, the optimal conditions for visualizing acute ischemic stroke were achievable.

  1. Virtual monochromatic imaging in dual-source and dual-energy CT for visualization of acute ischemic stroke

    Hara, Hidetake; Matsuzawa, Hiroki; Inoue, Toshiyuki; Abe, Shinji; Satoh, Hitoshi; Nakajima, Yasuo

    2015-01-01

    We have recently developed a phantom that simulates acute ischemic stroke. We attempted to visualize acute-stage cerebral infarction by applying virtual monochromatic images to this phantom using dual-energy CT (DECT). Virtual monochromatic images were created using DECT from 40 to 100 keV at every 10 keV and from 60 to 80 keV at every 1 keV, under three energy conditions of tube voltages with thin (Sn) filters. Calculation of the CNR values allowed us to evaluate the visualization of acute-stage cerebral infarction. The CNR value of a virtual monochromatic image was the highest at 68 keV under 80 kV / Sn 140 kV, at 72 keV under 100 kV / Sn 140 kV, and at 67 keV under 140 kV / 80 kV. The CNR values of virtual monochromatic images between 65 and 75 keV were significantly higher than those obtained for all other created energy images. Therefore, optimal conditions for visualizing acute ischemic stroke were achievable.

  2. Identifying diffused nitrate sources in a stream in an agricultural field using a dual isotopic approach

    Ding, Jingtao [School of Environment, Beijing Normal University, Beijing 100875 (China); Xi, Beidou, E-mail: xbd100012@163.com [Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Gao, Rutai; He, Liansheng; Liu, Hongliang [Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Dai, Xuanli; Yu, Yijun [Changzhou Environmental Monitoring Center, Jiangsu 213001 (China)

    2014-06-01

    Nitrate (NO{sub 3}{sup −}) pollution is a severe problem in aquatic systems in Taihu Lake Basin in China. A dual isotope approach (δ{sup 15}N-NO{sub 3}{sup −} and δ{sup 18}O-NO{sub 3}{sup −}) was applied to identify diffused NO{sub 3}{sup −} inputs in a stream in an agricultural field at the basin in 2013. The site-specific isotopic characteristics of five NO{sub 3}{sup −} sources (atmospheric deposition, AD; NO{sub 3}{sup −} derived from soil organic matter nitrification, NS; NO{sub 3}{sup −} derived from chemical fertilizer nitrification, NF; groundwater, GW; and manure and sewage, M and S) were identified. NO{sub 3}{sup −} concentrations in the stream during the rainy season [mean ± standard deviation (SD) = 2.5 ± 0.4 mg/L] were lower than those during the dry season (mean ± SD = 4.0 ± 0.5 mg/L), whereas the δ{sup 18}O-NO{sub 3}{sup −} values during the rainy season (mean ± SD = + 12.3 ± 3.6‰) were higher than those during the dry season (mean ± SD = + 0.9 ± 1.9‰). Both chemical and isotopic characteristics indicated that mixing with atmospheric NO{sub 3}{sup −} resulted in the high δ{sup 18}O values during the rainy season, whereas NS and M and S were the dominant NO{sub 3}{sup −} sources during the dry season. A Bayesian model was used to determine the contribution of each NO{sub 3}{sup −} source to total stream NO{sub 3}{sup −}. Results showed that reduced N nitrification in soil zones (including soil organic matter and fertilizer) was the main NO{sub 3}{sup −} source throughout the year. M and S contributed more NO{sub 3}{sup −} during the dry season (22.4%) than during the rainy season (17.8%). AD generated substantial amounts of NO{sub 3}{sup −} in May (18.4%), June (29.8%), and July (24.5%). With the assessment of temporal variation of diffused NO{sub 3}{sup −} sources in agricultural field, improved agricultural management practices can be implemented to protect the water resource and avoid further water

  3. Dual activity of certain HIT-proteins: A. thaliana Hint4 and C. elegans DcpS act on adenosine 5'-phosphosulfate as hydrolases (forming AMP) and as phosphorylases (forming ADP).

    Guranowski, Andrzej; Wojdyła, Anna Maria; Zimny, Jarosław; Wypijewska, Anna; Kowalska, Joanna; Jemielity, Jacek; Davis, Richard E; Bieganowski, Paweł

    2010-01-01

    Histidine triad (HIT)-family proteins interact with different mono- and dinucleotides and catalyze their hydrolysis. During a study of the substrate specificity of seven HIT-family proteins, we have shown that each can act as a sulfohydrolase, catalyzing the liberation of AMP from adenosine 5'-phosphosulfate (APS or SO(4)-pA). However, in the presence of orthophosphate, Arabidopsis thaliana Hint4 and Caenorhabditis elegans DcpS also behaved as APS phosphorylases, forming ADP. Low pH promoted the phosphorolytic and high pH the hydrolytic activities. These proteins, and in particular Hint4, also catalyzed hydrolysis or phosphorolysis of some other adenylyl-derivatives but at lower rates than those for APS cleavage. A mechanism for these activities is proposed and the possible role of some HIT-proteins in APS metabolism is discussed. PMID:19896942

  4. Optimal image reconstruction phase at low and high heart rates in dual-source CT coronary angiography

    Araoz, Philip A; Kirsch, Jacobo; Primak, Andrew N.; Braun, Natalie N.; Saba, Osama; Williamson, Eric E.; Harmsen, W. Scott; Mandrekar, Jayawant N.; McCollough, Cynthia H.

    2009-01-01

    The purpose of this study was to determine the cardiac phase having the highest coronary sharpness for low and high heart rate patients scanned with dual source CT (DSCT) and to compare coronary image sharpness over different cardiac phases. DSCT coronary CT scans for 30 low heart rate (≤ 70 beats per minute- bpm) and 30 high heart rate (>70 bpm) patients were reconstructed into different cardiac phases, starting at 30% and increasing at 5% increments until 70%. A blinded observer graded imag...

  5. Giant coronary aneurysm caused by Kawasaki disease: consistency between catheter angiography and electrocardiogram gated dual-source computed tomography angiography

    Hwang, Eun-Ha; Ju, Jung-Ki; Cho, Min-Jung; Lee, Ji-Won; Lee, Hyoung-Doo

    2015-01-01

    We present the case of a 5-year-old child with coronary complications due to Kawasaki disease; this patient unintentionally underwent both dual-source computed tomography (DSCT) coronary angiography and invasive coronary angiographic examination in 2 months. This case highlights the strong consistency of the results between DSCT coronary angiography and invasive coronary angiography. Compared to conventional invasive coronary angiography, DSCT coronary angiography offered additional advantage...

  6. Giant coronary aneurysm caused by Kawasaki disease: consistency between catheter angiography and electrocardiogram gated dual-source computed tomography angiography.

    Hwang, Eun-Ha; Ju, Jung-Ki; Cho, Min-Jung; Lee, Ji-Won; Lee, Hyoung-Doo

    2015-12-01

    We present the case of a 5-year-old child with coronary complications due to Kawasaki disease; this patient unintentionally underwent both dual-source computed tomography (DSCT) coronary angiography and invasive coronary angiographic examination in 2 months. This case highlights the strong consistency of the results between DSCT coronary angiography and invasive coronary angiography. Compared to conventional invasive coronary angiography, DSCT coronary angiography offered additional advantages such as minimal invasiveness and less radiation exposure. PMID:26770226

  7. Performance of turbo high-pitch dual-source CT for coronary CT angiography: first ex vivo and patient experience

    Morsbach, Fabian; Gordic, Sonja; Husarik, Daniela; Frauenfelder, Thomas; Alkadhi, Hatem [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); Desbiolles, Lotus; Leschka, Sebastian [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); Kantonsspital St. Gallen, Divison of Radiology and Nuclear Medicine, St. Gallen (Switzerland); Schmidt, Bernhard; Allmendinger, Thomas [Siemens AG, Healthcare Sector, Forchheim (Germany); Wildermuth, Simon [Kantonsspital St. Gallen, Divison of Radiology and Nuclear Medicine, St. Gallen (Switzerland)

    2014-08-15

    To evaluate image quality, maximal heart rate allowing for diagnostic imaging, and radiation dose of turbo high-pitch dual-source coronary computed tomographic angiography (CCTA). First, a cardiac motion phantom simulating heart rates (HRs) from 60-90 bpm in 5-bpm steps was examined on a third-generation dual-source 192-slice CT (prospective ECG-triggering, pitch 3.2; rotation time, 250 ms). Subjective image quality regarding the presence of motion artefacts was interpreted by two readers on a four-point scale (1, excellent; 4, non-diagnostic). Objective image quality was assessed by calculating distortion vectors. Thereafter, 20 consecutive patients (median, 50 years) undergoing clinically indicated CCTA were included. In the phantom study, image quality was rated diagnostic up to the HR75 bpm, with object distortion being 1 mm or less. Distortion increased above 1 mm at HR of 80-90 bpm. Patients had a mean HR of 66 bpm (47-78 bpm). Coronary segments were of diagnostic image quality for all patients with HR up to 73 bpm. Average effective radiation dose in patients was 0.6 ± 0.3 mSv. Our combined phantom and patient study indicates that CCTA with turbo high-pitch third-generation dual-source 192-slice CT can be performed at HR up to 75 bpm while maintaining diagnostic image quality, being associated with an average radiation dose of 0.6 mSv. (orig.)

  8. Dual-source CT coronary angiography in patients with atrial fibrillation: Comparison with single-source CT

    Wang Yining [Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing (China)], E-mail: yiningpumc@hotmail.com; Zhang Zhuhua [Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing (China)], E-mail: yiningpumc@sina.com; Kong Lingyan [Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing (China)], E-mail: klyan78@hotmail.com; Song Lan [Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing (China)], E-mail: sallysonglan@sina.com; Merges, Reto D. [CT Research Collaboration, Siemens Ltd. (China)], E-mail: reto.merges@siemens.com; Chen Jiuhong [CT Research Collaboration, Siemens Ltd. (China)], E-mail: jiuhong.chen@siemens.com; Jin Zhengyu [Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing (China)], E-mail: jin_zhengyu@sina.com

    2008-12-15

    Objective: To evaluate the performance of dual-source computed tomography (DSCT) for the visualization of the coronary arteries in a population with atrial fibrillation (AF) compared to single-source CT (SSCT) and to explore the impact of patients' heart rate (HR) on image quality (IQ) and reconstruction timing. Methods: Thirty consecutive patients (11 male, 19 female; 69.0 {+-} 9.2 years old) with suspected coronary artery disease and permanent AF were examined on a DSCT scanner (120 kV, 400 mAs/rot, 0.33 s rotation time, 64 x 0.6 mm collimation, pitch 0.20-0.28, Siemens Somatom Definition). Patients were divided into two groups: low and medium HR group (HR {<=} 80 bpm, n = 14) and high HR group (HR > 80 bpm, n = 16). Five of the patients also underwent conventional coronary angiography (CAG). The raw data from both tube detector arrays were reconstructed as DSCT data using a routine algorithm (temporal resolution of 83 ms). The raw data from one tube detector array was reconstructed separately on the same system using a routine single source algorithm (temporal resolution of 83-165 ms) and defined as virtual SSCT data. Image quality was assessed using a four-point grading scale from excellent (1) to non-assessable (4). Results: IQ of the DSCT data was significantly better than that of the virtual SSCT data (mean score 1.33 {+-} 0.61 vs. 1.80 {+-} 1.02; Z = -8.755, P = 0.000). 98.6% of the segments shown in DSCT were diagnostic, compared with 89.9% of the segments in virtual SSCT, {chi}{sup 2} = 32.595, P = 0.000. In DSCT group, IQ of low HR group was also better than that of high HR group, although the difference was not as big (mean score 1.25 {+-} 0.52 vs. 1.38 {+-} 0.66; Z = -2.227, P = 0.026). The mean HR of low HR group and high HR group were 67.4 {+-} 8.5 beats per minute (bpm) and 94.2 {+-} 8.8 bpm (t = -8.499, P = 0.000). The range of the variation of HR was higher in high HR group than in low HR group (mean difference between maximum and minimum HR

  9. Dual-source CT coronary angiography in patients with atrial fibrillation: Comparison with single-source CT

    Objective: To evaluate the performance of dual-source computed tomography (DSCT) for the visualization of the coronary arteries in a population with atrial fibrillation (AF) compared to single-source CT (SSCT) and to explore the impact of patients' heart rate (HR) on image quality (IQ) and reconstruction timing. Methods: Thirty consecutive patients (11 male, 19 female; 69.0 ± 9.2 years old) with suspected coronary artery disease and permanent AF were examined on a DSCT scanner (120 kV, 400 mAs/rot, 0.33 s rotation time, 64 x 0.6 mm collimation, pitch 0.20-0.28, Siemens Somatom Definition). Patients were divided into two groups: low and medium HR group (HR ≤ 80 bpm, n = 14) and high HR group (HR > 80 bpm, n = 16). Five of the patients also underwent conventional coronary angiography (CAG). The raw data from both tube detector arrays were reconstructed as DSCT data using a routine algorithm (temporal resolution of 83 ms). The raw data from one tube detector array was reconstructed separately on the same system using a routine single source algorithm (temporal resolution of 83-165 ms) and defined as virtual SSCT data. Image quality was assessed using a four-point grading scale from excellent (1) to non-assessable (4). Results: IQ of the DSCT data was significantly better than that of the virtual SSCT data (mean score 1.33 ± 0.61 vs. 1.80 ± 1.02; Z = -8.755, P = 0.000). 98.6% of the segments shown in DSCT were diagnostic, compared with 89.9% of the segments in virtual SSCT, χ2 = 32.595, P = 0.000. In DSCT group, IQ of low HR group was also better than that of high HR group, although the difference was not as big (mean score 1.25 ± 0.52 vs. 1.38 ± 0.66; Z = -2.227, P = 0.026). The mean HR of low HR group and high HR group were 67.4 ± 8.5 beats per minute (bpm) and 94.2 ± 8.8 bpm (t = -8.499, P = 0.000). The range of the variation of HR was higher in high HR group than in low HR group (mean difference between maximum and minimum HR 79.5 ± 21.0 vs. 49.9 ± 21

  10. Quantitative assessment of pure aortic valve regurgitation with dual-source CT

    Aim: To assess the severity of pure aortic regurgitation by measuring regurgitation volumes (RV) and fractions (RF) with dual-source computed tomography (DSCT) as compared to magnetic resonance imaging (MRI) and echocardiography. Materials and methods: Thirty-eight patients (15 men, 23 women; mean age 46 ± 11 years) with isolated aortic valve regurgitation underwent retrospectively electrocardiogram (ECG)-gated DSCT, echocardiography, and MRI. Stroke volumes of the left and right ventricles were measured at DSCT and MRI. Thus, RVs and RFs were calculated and compared. The agreement between DSCT and MRI was tested by intraclass correlation coefficient and Bland–Altman analyses. Spearman’s rank order correlation and weighted κ tests were used for testing correlations of AR severity between DSCT results and corresponding echocardiographic grades. Results: The RV and RF measured by DSCT were not significantly different from those measured using MRI (p = 0.71 and 0.79). DSCT correlated well with MRI for the measurement of RV (rI = 0.86, pI =0.90, ps = 0.95, ps = 0.95, p<0.001). Inter-technique agreement between DSCT and two-dimensional transthoracic echocardiography (2DTTE) regarding the grading of the severity of AR was excellent (κ = 0.90), and good agreement was also obtained between MRI and 2DTTE assessments of the severity of AR (κ = 0.87). Conclusion: DSCT using a volume approach can be used to quantitatively determine the severity of pure aortic regurgitation when compared with MRI and echocardiography.

  11. Measurements of Coronary Artery Aneurysms Due to Kawasaki Disease by Dual-Source Computed Tomography (DSCT).

    Tsujii, Nobuyuki; Tsuda, Etsuko; Kanzaki, Suzu; Kurosaki, Kenichi

    2016-03-01

    Diameters of coronary artery aneurysms (CAAs) complicating acute phase KD can strongly predict the long-term prognosis of coronary artery lesions (CAL). Recently, computed tomographic angiography (CTA) has been used to detect CAL, and the purpose of this study was to determine whether coronary artery diameters measurements by CTA using dual-source computed tomography (DSCT) can be used instead of coronary angiogram (CAG) measurements. Twenty-five patients (22 males and three females) with CAL due to KD, who had undergone both CTA and CAG within one year, were retrospectively evaluated between 2007 and 2013. A prospective electrocardiogram-triggered CTA was performed on a DSCT (SOMATOM(®) Definition, Siemens Healthcare, Germany). Two pediatric cardiologists independently measured the diameters of CAAs twice in each maximum intensity projection (MIP), curved multiplaner reconstruction (MPR) and CAG. We measured 161 segments in total (segment 1-3, 5-7, 11, 13). Diagnostic accuracy was expressed as κ coefficient. A Bland-Altman analysis was also used to assess the intra-observer, inter-observer and inter-modality agreement. The diagnostic quality of CTA was excellent (κ = 0.93). Excellent inter-observer agreement for the diameters of CAAs was obtained for MIP, MPR and CAG and for the intra-observer agreement. The inter-modality agreement was also excellent in measurements of CAA (MPR-CAG: y = 0.9x + 0.40, r = 0.97, p < 0.0001 MIP-CAG: y = x + 0.1, r = 0.94, p < 0.0001). These values in normal coronary arteries were also obtained. We found a significant correlation between CTA and CAG in measuring the coronary arteries. We conclude that measuring coronary artery diameters by CTA is reliable and useful. PMID:26515298

  12. Dual-source CT in the detection of coronary artery disease: a Meta analysis

    Objective: To conduct a Meta analysis based evaluation of dual-source computed tomography (DSCT) in the diagnosis of coronary artery disease (CAD). Methods: Literatures published from January 2006 to July 2009, including in English or Chinese languages, were searched in Medline, China National Knowledge Infrastructure (CNKI), and Chinese Medical Association Digital Periodicals (CMADP). A study was enrolled if it: (1) used DSCT angiography as the diagnostic test for the detection of significant coronary stenosis ( ≥ 50% diameter stenosis) in patients with suspected CAD; (2) used coronary angiography as the reference standard. The pooled sensitivity and specificity of the 95% confidence interval (95% CI) were acquired based on the bivariate random-effects model. Hierarchical weighted symmetric summary receiver-operating curve (HSROC) was also estimated. The pooled likelihood ratios were calculated based on the pooled sensitivity and specificity. Combined with the pooled likelihood ratios, the clinical utility of the results was estimated according to Bayes' theory. Results: Total of ten articles enrolled in this study, included 1271 patients. The mean rate of non-evaluable patients and segments were 5.6% (33/590) and 2.3% (271/11 745), respectively. The pooled statistical results were as follows: the sensitivity and specificity were 99% (97%-99%) and 86% (79%-90%), respectively; the positive and negative likelihood ratio were 6.84 and 0.01, respectively. If a pre-test probability was below 84%, the likelihood of disease was less than 5% on a negative diagnosis of DSCT. If a pre-test probability was above 13%, the likelihood of' disease was more than 50% on a positive diagnosis of DSCT. Conclusions: DSCT angiography presents good diagnostic performance in the detection of CAD; however, it could not completely replace conventional coronary angiography. (authors)

  13. Contrast-enhanced coronary artery visualization by dual-source computed tomography-Initial experience

    Achenbach, Stephan [Department of Cardiology, University of Erlangen-Nuernberg, Ulmenweg 18, 91054 Erlangen (Germany) and Department of Radiology, Massachusetts General Hospital, Boston, MA (United States)]. E-mail: stephan.achenbach@med2.med.uni-erlangen.de; Ropers, Dieter [Department of Cardiology, University of Erlangen-Nuernberg, Ulmenweg 18, 91054 Erlangen (Germany); Kuettner, Axel [Institute for Diagnostic Radiology, University of Erlangen-Nuernberg, Erlangen (Germany); Flohr, Thomas [Siemens Medical Solutions, Forchheim (Germany); Ohnesorge, Bernd [Siemens Medical Solutions, Forchheim (Germany); Bruder, Herbert [Siemens Medical Solutions, Forchheim (Germany); Theessen, Heike [Siemens Medical Solutions, Forchheim (Germany); Karakaya, Meri [Institute of Medical Physics, University of Erlangen-Nuernberg, Erlangen (Germany); Daniel, Werner G. [Department of Cardiology, University of Erlangen-Nuernberg, Ulmenweg 18, 91054 Erlangen (Germany); Bautz, Werner [Institute for Diagnostic Radiology, University of Erlangen-Nuernberg, Erlangen (Germany); Kalender, Willi A. [Institute of Medical Physics, University of Erlangen-Nuernberg, Erlangen (Germany); Anders, Katharina [Institute for Diagnostic Radiology, University of Erlangen-Nuernberg, Erlangen (Germany)

    2006-03-15

    Multi-detector computed tomography (CT) scanners, by virtue of their high temporal and spatial resolution, permit imaging of the coronary arteries. However, motion artifacts, especially in patients with higher heart rates, can impair image quality. We thus evaluated the performance of a new dual-source CT (DSCT) with a heart rate independent temporal resolution of 83 ms for the visualization of the coronary arteries in 14 consecutive patients. Methods: Fourteen patients (mean age 61 years, mean heart rate 71 min{sup -1}) were studied by DSCT. The system combines two arrays of an X-ray tube plus detector (64 slices) mounted on a single gantry at an angle of 90{sup o} With a rotation speed of 330 ms, a temporal resolution of 83 ms (one-quarter rotation) can be achieved independent of heart rate. For data acquisition, intraveous contrast agent was injected at a rate of 5 ml/s. Images were reconstructed with 0.75 slice thickness and 0.5 mm increment. The data sets were evaluated concerning visibility of the coronary arteries and occurrence of motion artifact. Results: Visualization of the coronary arteries was successful in all patients. Most frequently, image reconstruction at 70% of the cardiac cycle provided for optimal image quality (50% of patients). Of a total of 226 coronary artery segments, 222 (98%) were visualized free of motion artifact. In summary, DSCT constitutes a promising new concept for cardiac CT. High and heart rate independent temporal resolution permits imaging of the coronary arteries without motion artifacts in a substantially increased number of patients as compared to earlier scanner generations. Larger and appropriately designed studies will need to determine the method's accuracy for detection of coronary artery stenoses.

  14. Dual-source CT assessment of ventricular function in healthy and infarcted myocardium: An animal study

    Mahnken, Andreas H., E-mail: mahnken@rad.rwth-aachen.de [Department of Diagnostic Radiology, University Hospital, RWTH Aachen University, Pauwelsstrasse 30, D-52074 Aachen (Germany); Applied Medical Engineering, Helmholtz Institute of Biomedical Engineering, RWTH Aachen University, Pauwelsstrasse 20, D-52074 Aachen (Germany); Bruners, Philipp [Department of Diagnostic Radiology, University Hospital, RWTH Aachen University, Pauwelsstrasse 30, D-52074 Aachen (Germany); Applied Medical Engineering, Helmholtz Institute of Biomedical Engineering, RWTH Aachen University, Pauwelsstrasse 20, D-52074 Aachen (Germany); Bornikoel, Christoph M. [Department of Diagnostic Radiology, University Hospital, RWTH Aachen University, Pauwelsstrasse 30, D-52074 Aachen (Germany); Flohr, Thomas; Schmidt, Bernhard [Siemens Healthcare, CTE, Siemensstrasse 1, D-91301 Forchheim (Germany); Voelk, Markus [MVZ Theresientor, Stadtgraben 10, D-94315 Straubing (Germany); Krombach, Gabriele A.; Guenther, Rolf W.; Muehlenbruch, Georg [Department of Diagnostic Radiology, University Hospital, RWTH Aachen University, Pauwelsstrasse 30, D-52074 Aachen (Germany)

    2011-03-15

    Purpose: To assess global and regional ventricular function in the presence of myocardial infarction (MI) using cardiac dual-source computed tomography (DSCT) in comparison to magnetic resonance (MR) imaging. Materials and methods: Fourteen pigs (58.6 {+-} 8.9 kg) were included in this study. In seven animals acute MI was induced by temporary balloon occlusion of the left circumflex artery. Thereafter, DSCT and MR imaging were performed with standardized examination protocols. Left (LV) and right ventricular (RV) volumes, ejection fraction (EF), peak filling rate (PFR), and peak ejection rate (PER) as well as LV myocardial mass were calculated. LV wall motion was visually assessed from cine loops. Data was analyzed using Bland-Altman plots, Lin's concordance-correlation coefficient ({rho}{sub c}) and weighted kappa statistics. Results: Ventricular volumes and mass as determined by DSCT correlated well with MR imaging. Mean LV-EF was 49.4 {+-} 16.5% on DSCT and 50.0 {+-} 16.1% on MR imaging ({rho}{sub c} = 0.9928). The corresponding mean RV-EF results were 45.9 {+-} 10.6% and 45.8 {+-} 10.6% ({rho}{sub c} = 0.9969), respectively. Bland-Altman plots revealed no systematic errors, but PER and PFR showed a relevant scattering. Regional wall motion scores agreed in 216/224 myocardial segments ({kappa} = 0.925). Conclusion: DSCT permits the reliable assessment of global and regional function in healthy and infarcted myocardium, but is not yet suited for the assessment of dynamic functional parameters like PER and PFR.

  15. Contrast-enhanced coronary artery visualization by dual-source computed tomography-Initial experience

    Multi-detector computed tomography (CT) scanners, by virtue of their high temporal and spatial resolution, permit imaging of the coronary arteries. However, motion artifacts, especially in patients with higher heart rates, can impair image quality. We thus evaluated the performance of a new dual-source CT (DSCT) with a heart rate independent temporal resolution of 83 ms for the visualization of the coronary arteries in 14 consecutive patients. Methods: Fourteen patients (mean age 61 years, mean heart rate 71 min-1) were studied by DSCT. The system combines two arrays of an X-ray tube plus detector (64 slices) mounted on a single gantry at an angle of 90o With a rotation speed of 330 ms, a temporal resolution of 83 ms (one-quarter rotation) can be achieved independent of heart rate. For data acquisition, intraveous contrast agent was injected at a rate of 5 ml/s. Images were reconstructed with 0.75 slice thickness and 0.5 mm increment. The data sets were evaluated concerning visibility of the coronary arteries and occurrence of motion artifact. Results: Visualization of the coronary arteries was successful in all patients. Most frequently, image reconstruction at 70% of the cardiac cycle provided for optimal image quality (50% of patients). Of a total of 226 coronary artery segments, 222 (98%) were visualized free of motion artifact. In summary, DSCT constitutes a promising new concept for cardiac CT. High and heart rate independent temporal resolution permits imaging of the coronary arteries without motion artifacts in a substantially increased number of patients as compared to earlier scanner generations. Larger and appropriately designed studies will need to determine the method's accuracy for detection of coronary artery stenoses

  16. Dual-source CT coronary angiography in patients with premature heart-beats: initial experience

    Objective: To evaluate the feasibility of dual-source computed tomography (DSCT) coronary angiography in a population with premature heart-beats. Methods: Seventy patients with suspected coronary artery disease and premature heart-beats were routinely imaged on a DSCT scanner (Somatom Definition, Siemens AG, Germany). The images were reconstmcted before and after ECG editing. Two readers independently assessed image quality of all coronary segments using a four-point grading scale from excellent (1) to non-assessable (4). The results of the two groups were compared with a paired t-test, and a P value of less than 0.05 was considered significant. Results: The mean heart rate during examination ranged from 49 to 111 bpm[ mean(70.7±12.4) bpm]. Twenty-eight of 70 patients with relatively small variability of the heart rate [(41.0±18.4) bpm] got diagnostic image quality without ECG editing. In other 42 patients with larger variability of the heart rate [(71.4±28.7) bpm], the mean image quality scores were 2.09±1.27 and 1.50±0.79 before and after ECG editing, there was a significant difference (t= 13.764, P2=121.846, P<0.01). Finally, the diagnostic image accounted 98.0% (1014/1035) in all segments of 70 patients. Conclusion: DSCT can provide diagnostic images for patients with premature heart-beats. The image quality in patients with larger variability of the heart rate can be significantly improved through ECG editing. (authors)

  17. Dual-source CT coronary imaging in heart transplant recipients: image quality and optimal reconstruction interval

    The image quality and optimal reconstruction interval for coronary arteries in heart transplant recipients undergoing non-invasive dual-source computed tomography (DSCT) coronary angiography was evaluated. Twenty consecutive heart transplant recipients who underwent DSCT coronary angiography were included (19 male, one female; mean age 63.1±10.7 years). Data sets were reconstructed in 5% steps from 30% to 80% of the R-R interval. Two blinded independent observers assessed the image quality of each coronary segments using a five-point scale (from 0 = not evaluative to 4=excellent quality). A total of 289 coronary segments in 20 heart transplant recipients were evaluated. Mean heart rate during the scan was 89.1±10.4 bpm. At the best reconstruction interval, diagnostic image quality (score ≥2) was obtained in 93.4% of the coronary segments (270/289) with a mean image quality score of 3.04± 0.63. Systolic reconstruction intervals provided better image quality scores than diastolic reconstruction intervals (overall mean quality scores obtained with the systolic and diastolic reconstructions 3.03±1.06 and 2.73±1.11, respectively; P<0.001). Different systolic reconstruction intervals (35%, 40%, 45% of RR interval) did not yield to significant differences in image quality scores for the coronary segments (P=0.74). Reconstructions obtained at the systolic phase of the cardiac cycle allowed excellent diagnostic image quality coronary angiograms in heart transplant recipients undergoing DSCT coronary angiography. (orig.)

  18. Diagnostic accuracy of dual-source CT coronary angiography in patients with atrial fibrillation: Meta analysis

    Sun, Gang, E-mail: cjr.sungang@vip.163.com [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Li, Min [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Jiang, Zhi-wei [Department of Health Statistics, School of Public Health, Fourth Military Medical University, No. 169, Changle West Road, Xi’an, Shaanxi 710032 (China); Xu, Lin [Department of Medical Cardiology, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Peng, Zhao-hui; Ding, Juan; Li, Li [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Jin, Zhi-tao [Department of Cardiology, General Hospital of the Second Artillery, Beijing 100088 (China)

    2013-10-01

    Rationale and objective: To synthesize the available data to underscore the diagnostic accuracy of dual-source CT (DSCT) coronary angiography in patients with atrial fibrillation (AF). Materials and methods: We searched in the electronic databases of PubMed for all published studies that examined patients with AF using DSCT. We used an exact binomial rendition of the bivariate mixed-effects regression model to synthesize the diagnostic data. Results: The positive and negative likelihood ratios (LRs) at the patient level were 6.0 (CI, 3.6–10.1) and 0.03(CI, 0.004–0.2), respectively. The negative predictive values higher than 90% were available for a CAD prevalence <78%. The pooled vessel- and segment-level estimates showed higher positive and negative LRs than the patient-level estimates (15.3 [CI, 9.8–23.9] and 0.1 [CI, 0.07–0.3]; 25.1 [CI, 10.8–58.5] and 0.2 [CI, 0.2–0.3], respectively). No statistically significant heterogeneity between studies and publication bias were found at the patient level estimate. A sensitivity analysis showed that no study influenced the pooled results larger than 0.02. Conclusions: Cardiac angiography with DSCT can be applied as an imaging test for ruling out CAD in patient with AF. However, DSCT angiography may be not an effective tool for risk stratification for the high negative LR at the artery and segment levels.

  19. Diagnostic accuracy of dual-source CT coronary angiography in patients with atrial fibrillation: Meta analysis

    Rationale and objective: To synthesize the available data to underscore the diagnostic accuracy of dual-source CT (DSCT) coronary angiography in patients with atrial fibrillation (AF). Materials and methods: We searched in the electronic databases of PubMed for all published studies that examined patients with AF using DSCT. We used an exact binomial rendition of the bivariate mixed-effects regression model to synthesize the diagnostic data. Results: The positive and negative likelihood ratios (LRs) at the patient level were 6.0 (CI, 3.6–10.1) and 0.03(CI, 0.004–0.2), respectively. The negative predictive values higher than 90% were available for a CAD prevalence <78%. The pooled vessel- and segment-level estimates showed higher positive and negative LRs than the patient-level estimates (15.3 [CI, 9.8–23.9] and 0.1 [CI, 0.07–0.3]; 25.1 [CI, 10.8–58.5] and 0.2 [CI, 0.2–0.3], respectively). No statistically significant heterogeneity between studies and publication bias were found at the patient level estimate. A sensitivity analysis showed that no study influenced the pooled results larger than 0.02. Conclusions: Cardiac angiography with DSCT can be applied as an imaging test for ruling out CAD in patient with AF. However, DSCT angiography may be not an effective tool for risk stratification for the high negative LR at the artery and segment levels

  20. Adenosine-Associated Delivery Systems

    Kazemzadeh-Narbat, Mehdi; Annabi, Nasim; Tamayol, Ali; Oklu, Rahmi; Ghanem, Amyl; Khademhosseini, Ali

    2016-01-01

    Adenosine is a naturally occurring purine nucleoside in every cell. Many critical treatments such as modulating irregular heartbeat (arrhythmias), regulation of central nervous system (CNS) activity, and inhibiting seizural episodes can be carried out using adenosine. Despite the significant potential therapeutic impact of adenosine and its derivatives, the severe side effects caused by their systemic administration have significantly limited their clinical use. In addition, due to adenosine’s extremely short half-life in human blood (less than 10 s), there is an unmet need for sustained delivery systems to enhance efficacy and reduce side effects. In this paper, various adenosine delivery techniques, including encapsulation into biodegradable polymers, cell-based delivery, implantable biomaterials, and mechanical-based delivery systems, are critically reviewed and the existing challenges are highlighted. PMID:26453156

  1. Xenon ventilation CT using dual-source and dual-energy technique in children with bronchiolitis obliterans: correlation of xenon and CT density values with pulmonary function test results

    Xenon ventilation CT using dual-source and dual-energy technique is a recently introduced, promising functional lung imaging method. To expand its clinical applications evidence of additional diagnostic value of xenon ventilation CT over conventional chest CT is required. To evaluate the usefulness of xenon ventilation CT using dual-source and dual-energy technique in children with bronchiolitis obliterans (BO). Seventeen children (age 7-18 years; 11 boys) with BO underwent xenon ventilation CT using dual-source and dual-energy technique. Xenon and CT density values were measured in normal and hyperlucent lung regions on CT and were compared between the two regions. Volumes of hyperlucent regions and ventilation defects were calculated with thresholds determined by visual and histogram-based analysis. Indexed volumes of hyperlucent lung regions and ventilation defects were correlated with pulmonary function test results. Effective doses of xenon CT were calculated. Xenon (14.6 ± 6.4 HU vs 26.1 ± 6.5 HU; P 25-75, (γ = -0.68-0.88, P ≤ 0.002). Volume percentages of xenon ventilation defects (35.0 ± 16.4%)] were not significantly different from those of hyperlucent lung regions (38.2 ± 18.6%). However, mismatches between the volume percentages were variable up to 21.4-33.3%. Mean effective dose of xenon CT was 1.9 ± 0.5 mSv. In addition to high-resolution anatomic information, xenon ventilation CT using dual-source and dual-energy technique demonstrates impaired regional ventilation and its heterogeneity accurately in children with BO without additional radiation exposure. (orig.)

  2. Analysis of Pulmonary Vein Antrums Motion with Cardiac Contraction Using Dual-Source Computed Tomography

    de Guise, Jacques; Vu, Toni; Chartrand-Lefebvre, Carl; Blais, Danis; Lebeau, Martin; Nguyen, Nhu-Tram; Roberge, David

    2016-01-01

    Purpose: The purpose of the study was to determine the extent of displacement of the pulmonary vein antrums resulting from the intrinsic motion of the heart using 4D cardiac dual-source computed tomography (DSCT). Methods: Ten consecutive female patients were enrolled in this prospective planning study. In breath-hold, a contrast-injected cardiac 4-dimensional (4D) computed tomography (CT) synchronized to the electrocardiogram was obtained using a prospective sequential acquisition method including the extreme phases of systole and diastole. Right and left atrial fibrillation target volumes (CTVR and CTVL) were defined, with each target volume containing the antral regions of the superior and inferior pulmonary veins. Four points of interest were used as surrogates for the right superior and inferior pulmonary vein antrum (RSPVA and RIPVA) and the left superior and inferior pulmonary vein antrum (LSPVA and LIPVA). On our 4D post-processing workstation (MIM Maestro™, MIM Software Inc.), maximum displacement of each point of interest from diastole to systole was measured in the mediolateral (ML), anteroposterior (AP), and superoinferior (SI) directions. Results: Median age of the enrolled patients was 60 years (range, 56-71 years). Within the CTVR, the mean displacements of the superior and inferior surrogates were 3 mm vs. 1 mm (p=0.002), 2 mm vs. 0 mm (p= 0.001), and 3 mm vs. 0 mm (p=0.00001), in the ML, AP, and SI directions, respectively. On the left, mean absolute displacements of the LSPVA vs. LIPVA were similar at 4 mm vs. 1 mm (p=0.0008), 2 mm vs. 0 mm (p= 0.001), and 3 mm vs. 1 mm (p=0.00001) in the ML, AP, and SI directions. Conclusion: When isolated from breathing, cardiac contraction is associated with minimal inferior pulmonary veins motion and modest (1-6 mm) motion of the superior veins. Target deformation was thus of a magnitude similar or greater than target motion, limiting the potential gains of cardiac tracking. Optimal strategies for cardiac

  3. Cardiac dual-source CT for the preoperative assessment of patients undergoing bariatric surgery

    Aim: To assess the diagnostic value of coronary dual-source computed tomography (DSCT) as a comprehensive, non-invasive tool in the preoperative cardiac evaluation of patients undergoing bariatric surgery. Materials and methods: Thirty consecutive obese [average body mass index (BMI): 45 ± 7.6, range: 35–59] patients (24 women; six men; median age: 52 ± 15 years) were enrolled in this institutional review board (IRB)-approved, Health Insurance Portability and Accountability Act of 1996 (HIPAA)-compliant prospective study. Calcium scoring (CaS) and electrocardiography (ECG)-gated images of the coronary arteries were obtained with a large body habitus protocol (120 kV; 430 mAs; 100 ml iodinated contrast medium at 7 ml/s injection rate) on a DSCT machine. Qualitative (four-point: 1 = excellent to 4 = not delineable) coronary segmental analysis, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) measurements were performed. The presence and degree of vascular disease (four-grade scale: mild to severe) was correlated with CaS and cardiovascular (CV) risk stratification blood tests. In patients with severe stenosis (>70%), findings were compared with cardiac nuclear medicine imaging (single photon-emission computed tomography; SPECT) imaging. Results: The average HR, enhancement, and quality score were 64 ± 7 beats/min, 288 ± 66 HU and 1.8 ± .5, respectively. Ninety-three percent (417/450) of the coronary segments were rated diagnostic. The SNRs and CNRs were 17 ± 9 and 12 ± 7 for the right coronary artery; 17 ± 8 and 12 ± 7 for the left main coronary artery; 16 ± 9 and 11 ± 7 for the left anterior descending coronary artery; and 15 ± 7 and 10 ± 6 for the left circumflex coronary artery. Ten of the 30 patients (33%) demonstrated coronary artery disease (CAD) of which two (6%) showed three-vessel disease. Four (13%) patients showed severe disease: in three of which the presence of significant stenosis was confirmed by SPECT and by catheter

  4. Assessment of left ventricular function and mass in dual-source computed tomography coronary angiography

    Jensen, Christoph J., E-mail: c.jensen@contilia.d [Department of Cardiology and Angiology, Elisabeth Hospital, Essen (Germany); Jochims, Markus [Department of Cardiology and Angiology, Elisabeth Hospital, Essen (Germany); Hunold, Peter; Forsting, Michael; Barkhausen, Joerg [Department of Diagnostic and Interventional Radiology and Neuroradiology, University of Essen (Germany); Sabin, Georg V.; Bruder, Oliver [Department of Cardiology and Angiology, Elisabeth Hospital, Essen (Germany); Schlosser, Thomas [Department of Diagnostic and Interventional Radiology and Neuroradiology, University of Essen (Germany)

    2010-06-15

    Purpose: To quantify left ventricular (LV) function and mass (LVM) derived from dual-source computed tomography (DSCT) and the influence of beta-blocker administration compared to cardiac magnetic resonance imaging (CMR). Methods: Thirty-two patients undergoing cardiac DSCT and CMR were included, where of fifteen received metoprolol intravenously before DSCT. LV parameters were calculated by the disc-summation method (DSM) and by a segmented region-growing algorithm (RGA). All data sets were analyzed by two blinded observers. Interobserver agreement was tested by the intraclass correlation coefficient. Results.: 1. Using DSM LV parameters were not statistically different between DSCT and CMR in all patients (DSCT vs. CMR: EF 63 {+-} 8% vs. 64 {+-} 8%, p = 0.47; EDV 136 {+-} 36 ml vs. 138 {+-} 35 ml, p = 0.66; ESV 52 {+-} 21 ml vs. 52 {+-} 22 ml, p = 0.61; SV 83 {+-} 22 ml vs. 87 {+-} 19 ml, p = 0.22; CO 5.4 {+-} 0.9 l/min vs. 5.7 {+-} 1.2 l/min, p = 0.09, LVM 132 {+-} 33 g vs. 132 {+-} 33 g, p = 0.99). 2. In a subgroup of 15 patients beta-blockade prior to DSCT resulted in a lower ejection fraction (EF), stroke volume (SV), cardiac output (CO) and increase in end systolic volume (ESV) in DSCT (EF 59 {+-} 8% vs. 62 {+-} 9%; SV 73 {+-} 17 ml vs. 81 {+-} 15 ml; CO 5.7 {+-} 1.2 l/min vs. 5.0 {+-} 0.8 l/min; ESV 52 {+-} 27 ml vs. 57 {+-} 24 ml, all p < 0.05). 3. Analyzing the RGA parameters LV volumes were not significantly different compared to DSM, whereas LVM was higher using RGA (177 {+-} 31 g vs. 132 {+-} 33 g, p < 0.05). Interobserver agreement was excellent comparing DSM values with best agreement between RGA calculations. Conclusion: Left ventricular volumes and mass can reliably be assessed by DSCT compared to CMR. However, beta-blocker administration leads to statistically significant reduced EF, SV and CO, whereas ESV significantly increases. DSCT RGA reliably analyzes LV function, whereas LVM is overestimated compared to DSM.

  5. Assessment of left ventricular function and mass in dual-source computed tomography coronary angiography

    Purpose: To quantify left ventricular (LV) function and mass (LVM) derived from dual-source computed tomography (DSCT) and the influence of beta-blocker administration compared to cardiac magnetic resonance imaging (CMR). Methods: Thirty-two patients undergoing cardiac DSCT and CMR were included, where of fifteen received metoprolol intravenously before DSCT. LV parameters were calculated by the disc-summation method (DSM) and by a segmented region-growing algorithm (RGA). All data sets were analyzed by two blinded observers. Interobserver agreement was tested by the intraclass correlation coefficient. Results.: 1. Using DSM LV parameters were not statistically different between DSCT and CMR in all patients (DSCT vs. CMR: EF 63 ± 8% vs. 64 ± 8%, p = 0.47; EDV 136 ± 36 ml vs. 138 ± 35 ml, p = 0.66; ESV 52 ± 21 ml vs. 52 ± 22 ml, p = 0.61; SV 83 ± 22 ml vs. 87 ± 19 ml, p = 0.22; CO 5.4 ± 0.9 l/min vs. 5.7 ± 1.2 l/min, p = 0.09, LVM 132 ± 33 g vs. 132 ± 33 g, p = 0.99). 2. In a subgroup of 15 patients beta-blockade prior to DSCT resulted in a lower ejection fraction (EF), stroke volume (SV), cardiac output (CO) and increase in end systolic volume (ESV) in DSCT (EF 59 ± 8% vs. 62 ± 9%; SV 73 ± 17 ml vs. 81 ± 15 ml; CO 5.7 ± 1.2 l/min vs. 5.0 ± 0.8 l/min; ESV 52 ± 27 ml vs. 57 ± 24 ml, all p < 0.05). 3. Analyzing the RGA parameters LV volumes were not significantly different compared to DSM, whereas LVM was higher using RGA (177 ± 31 g vs. 132 ± 33 g, p < 0.05). Interobserver agreement was excellent comparing DSM values with best agreement between RGA calculations. Conclusion: Left ventricular volumes and mass can reliably be assessed by DSCT compared to CMR. However, beta-blocker administration leads to statistically significant reduced EF, SV and CO, whereas ESV significantly increases. DSCT RGA reliably analyzes LV function, whereas LVM is overestimated compared to DSM.

  6. Impact of an advanced image-based monoenergetic reconstruction algorithm on coronary stent visualization using third generation dual-source dual-energy CT: a phantom study

    Mangold, Stefanie [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Eberhard-Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); Cannao, Paola M. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); University of Milan, Scuola di Specializzazione in Radiodiagnostica, Milan (Italy); Schoepf, U.J. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Medical University of South Carolina, Division of Cardiology, Department of Medicine, Charleston, SC (United States); Wichmann, Julian L. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany); Canstein, Christian [Siemens Medical Solutions, Malvern, PA (United States); Fuller, Stephen R.; Varga-Szemes, Akos [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); Muscogiuri, Giuseppe; De Cecco, Carlo N. [Medical University of South Carolina, Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Charleston, SC (United States); University of Rome ' ' Sapienza' ' , Department of Radiological Sciences, Oncology and Pathology, Rome (Italy); Nikolaou, Konstantin [Eberhard-Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany)

    2016-06-15

    To evaluate the impact of an advanced monoenergetic (ME) reconstruction algorithm on CT coronary stent imaging in a phantom model. Three stents with lumen diameters of 2.25, 3.0 and 3.5 mm were examined with a third-generation dual-source dual-energy CT (DECT). Tube potential was set at 90/Sn150 kV for DE and 70, 90 or 120 kV for single-energy (SE) acquisitions and advanced modelled iterative reconstruction was used. Overall, 23 reconstructions were evaluated for each stent including three SE acquisitions and ten advanced and standard ME images with virtual photon energies from 40 to 130 keV, respectively. In-stent luminal diameter was measured and compared to nominal lumen diameter to determine stent lumen visibility. Contrast-to-noise ratio was calculated. Advanced ME reconstructions substantially increased lumen visibility in comparison to SE for stents ≤3 mm. 130 keV images produced the best mean lumen visibility: 86 % for the 2.25 mm stent (82 % for standard ME and 64 % for SE) and 82 % for the 3.0 mm stent (77 % for standard ME and 69 % for SE). Mean DLP for SE 120 kV and DE acquisitions were 114.4 ± 9.8 and 58.9 ± 2.2 mGy x cm, respectively. DECT with advanced ME reconstructions improves the in-lumen visibility of small stents in comparison with standard ME and SE imaging. (orig.)

  7. Impact of an advanced image-based monoenergetic reconstruction algorithm on coronary stent visualization using third generation dual-source dual-energy CT: a phantom study

    To evaluate the impact of an advanced monoenergetic (ME) reconstruction algorithm on CT coronary stent imaging in a phantom model. Three stents with lumen diameters of 2.25, 3.0 and 3.5 mm were examined with a third-generation dual-source dual-energy CT (DECT). Tube potential was set at 90/Sn150 kV for DE and 70, 90 or 120 kV for single-energy (SE) acquisitions and advanced modelled iterative reconstruction was used. Overall, 23 reconstructions were evaluated for each stent including three SE acquisitions and ten advanced and standard ME images with virtual photon energies from 40 to 130 keV, respectively. In-stent luminal diameter was measured and compared to nominal lumen diameter to determine stent lumen visibility. Contrast-to-noise ratio was calculated. Advanced ME reconstructions substantially increased lumen visibility in comparison to SE for stents ≤3 mm. 130 keV images produced the best mean lumen visibility: 86 % for the 2.25 mm stent (82 % for standard ME and 64 % for SE) and 82 % for the 3.0 mm stent (77 % for standard ME and 69 % for SE). Mean DLP for SE 120 kV and DE acquisitions were 114.4 ± 9.8 and 58.9 ± 2.2 mGy x cm, respectively. DECT with advanced ME reconstructions improves the in-lumen visibility of small stents in comparison with standard ME and SE imaging. (orig.)

  8. Reduction of radiation dose with electrocardiogram-pulsing windows technique in dual-source CT coronary angiography

    Objective: To evaluate the value of reducing radiation dose with decreased size of ECG-pulsing windows and influence on image quality in dual-source CT coronary angiography. Methods: 120 patients with stable heart rate(HR) were divided into four groups according to HR and the rang of ECG-pulsing windows in dual-source CT coronary angiography: HR<70 bpm and 61%∼77% R-R interval of ECG-pulsing windows, HR<70 bpm and 25%∼80% R-R interval of ECG-pulsing windows, HR>80 bpm and 31%∼47% R-R interval of ECG-pulsing windows, and HR>80 bpm and 25%∼80% R-R interval of ECG-pulsing windows was employed, respectively. The radiation dose parameters were recorded and image quality scores were performed. The image quality and radiation dose between two slow HR groups and between two fast HR groups were compared respectively. Result: The effective doses were (7.06 ± 2.13), (11.34±3.65), (6.67±1.97) and (9.92±3.15) mSv for four groups, respectively.The effective dose was decreased by 37.74% for slow HR and by 32.76% for fast HR using narrow ECG-pulsing windows. There was no difference on image quality between two slow HR groups and two fast HR groups. Conclusions: The proper application of narrow ECG-pulsing windows can reduce radiation exposure significantly to stable slow or fast HR patients in dual-source CT coronary angiography without sacrificing the image quality. (authors)

  9. Dual-source CT in blunt trauma patients: elimination of diaphragmatic motion using high-pitch spiral technique.

    Liang, Teresa; McLaughlin, Patrick; Arepalli, Chesnal D; Louis, Luck J; Bilawich, Ana-Maria; Mayo, John; Nicolaou, Savvas

    2016-04-01

    The purpose of this study was to compare diaphragmatic motion on dual-source high-pitch (DS-HP) and conventional single-source (SS) CT scans in trauma patients. Seventy-five consecutive trauma patients who presented to a level one trauma center over a 6-month period were scanned with a standardized whole body trauma CT protocol including both DS-HP chest (pitch = 2.1-2.5) and SS abdominal CT scans. Subjective analysis of diaphragmatic motion was performed by two readers using a four-point motion scale in seven regions of the diaphragm on coronal and axial slices. An overall confidence score to exclude a diaphragmatic tear was determined (1 to 10, 10: completely confident and 1: impossible to exclude). Wilcoxon rank sum tests were used for statistical analysis, and p confidence score of 9.85 for DS-HP was significantly better than the mean score of 7.66 for SS images (p confidence to exclude a diaphragmatic tear (κ = 0.45). Dual-source high-pitch CT scanning is advantageous as it allows for significantly better evaluation of diaphragmatic structures by minimizing motion artifacts on images of freely breathing trauma patients. PMID:26637401

  10. Plug-and-play Integration of dual-model based Knowledge Artefacts into an Open Source Ehr System.

    Krexner, Rabea; Duftschmid, Georg

    2014-01-01

    In this paper we present our experiences with extending an existing approach for an archetype-compliant collection and export of data according to the openEHR specifications within the open source EHR system OpenMRS. It allows an automatic generation of forms from templates, which were introduced by openEHR as an extension of the dual-model approach. Data entered in these forms can be exported in form of standardized EHR extracts. The use of templates allowed us to solve problems reported for the original archetype-based version of the approach, which were caused by the high optionality within archetypes. PMID:25160154

  11. A diode-pumped Nd:YAlO3 dual-wavelength yellow light source

    Zhang, Jing; Fu, Xihong; Zhai, Pei; Xia, Jing; Li, Shutao

    2013-11-01

    We present what is, to the best of our knowledge, the first diode-pumped Nd:YAlO3 (Nd:YAP) continuous-wave (cw) dual-wavelength yellow laser at 593 nm and 598 nm, based on sum-frequency generation between 1064 and 1339 nm in a-axis polarization using LBO crystal and between 1079 and 1341 nm in c-axis polarization using PPKTP crystal, respectively. At an incident pump power of 17.3 W, the maximum output power obtained at 593 nm and 598 nm is 0.18 W and 1.86 W, respectively. The laser experiment shows that Nd:YAP crystal can be used for an efficient diode-pumped dual-wavelength yellow laser system.

  12. Virtual unenhanced second generation dual-source CT of the liver: Is it time to discard the conventional unenhanced phase?

    Introduction: Dual-energy dual source CT can almost simultaneously image patients using two different tube potentials, allowing material decomposition and creation of ‘virtual unenhanced’ (VU) images from post-contrast series. Methods: 75 patients undergoing triple-phase liver CT examinations were imaged using a second generation dual-source CT machine with tube potentials 140/100 kVp. Post-processing VU series were derived from arterial and portal phases. Regions-of-interest from liver parenchyma and within fat (‘noise’ assessment) were drawn to compare VU series to conventional unenhanced (CU) series. Subjective analysis assessed image quality and the suitability of VU to replace CU series. Results: Mean Hounsfield unit (HU) values of liver were higher in the VU series: portal 51.9 (SD = 10.29), arterial 51.1 (SD = 10.05), compared to the CU series 49.2 (SD = 9.11); P < 0.001. However, Pearson's correlation of the VU and CU series remained excellent: 0.838 (portal), 0.831 (arterial). Bland–Altman plots also showed good agreement between both VU and the CU datasets. Noise measurements were significantly lower in both VU series (P < 0.001). For subjective analysis, image quality was rated as very good/excellent in 100% of CU images, 93.3% of portal VU and 88.7% of arterial VU series. Overall, portal VU and arterial VU images were acceptable replacements for the CU series in 97.4% and 96.1%, respectively. Post-processing was noted to create a number of artefacts in VU images – knowledge of these is essential for interpretation. Conclusions: Portal and arterial-derived VU images objectively correlate to CU images and demonstrate good image quality and acceptability. VU image sets could replace the conventional unenhanced images in the vast majority of cases, significantly reducing radiation dose.

  13. Dynamic myocardial stress perfusion imaging using fast dual-source CT with alternating table positions: initial experience

    Bamberg, Fabian; Becker, Christoph R.; Wintersperger, Bernd J.; Reiser, Maximilian F. [Ludwig Maximilians University, Department of Clinical Radiology, Munich (Germany); Klotz, Ernst; Flohr, Thomas; Schmidt, Bernhard [Siemens Healthcare, Forchheim (Germany); Becker, Alexander [Ludwig Maximilians University, Department of Cardiology, Munich (Germany); Nikolaou, Konstantin [Ludwig Maximilians University, Department of Clinical Radiology, Munich (Germany); University of Munich - Grosshadern Campus, Department of Clinical Radiology, Munich (Germany)

    2010-05-15

    To detail the principles of using model-based determination of regional myocardial blood flow (MBF) by computed tomography (CT) and demonstrate its in vivo applicability. Dual-source CT was performed with a dynamic protocol comprising acquisition with alternating table positions in ECG-triggered end-systolic timing every second for 30 s. The results of two reconstructions were merged into one final image stack (coverage 73 mm), with low spatial frequency components from a 360 reconstruction and high spatial frequency components from a dual-source cardiac partial image reconstruction. A parametric deconvolution technique was used to fit the time-attenuation curves (TAC), the maximum slope of which was used to derive MBF. One study participant underwent dynamic myocardial stress perfusion imaging (9.6 mSv) followed by invasive coronary angiography and measurement of fractional flow reserve as the gold standard. MBF was 159 ml/100 ml/min in the non-ischaemic anterolateral and 86 ml/100 ml/min in the inferoseptal ischaemic wall. This first evaluation indicates that mathematical modelling of voxel TACs can potentially be used to quantify differences in MBF in a clinical setting. If confirmed in feasibility studies, cardiac CT may allow for parallel assessment of morphology and haemodynamic relevance of coronary artery disease. (orig.)

  14. Comparison of carotid and cerebrovascular disease between diabetic and non-diabetic patients using dual-source CT

    Purpose: To clarify the differences of the carotid and cerebrovascular disease between patients with and without type 2 diabetes using dual-source CT angiography. Materials and methods: Dual-source CT angiography of the carotid and cerebrovascular arteries was performed in 79 type 2 diabetic patients and 207 non-diabetic patients. The type, extent and distribution of plaques, and luminal stenosis were compared. Results: Compared with non-diabetic patients, diabetic patients had a higher overall incidence of plaque (p 0.05), as well as for the number of diseased segments and the distribution of plaques; both mainly involved the bilateral cavernous segment of the internal carotid artery. As for the stenosis, non-obstructive lesions were more common in diabetic patients (p 0.05). Conclusion: Diabetes is associated with a higher incidence of plaque and non-obstructive stenosis. However, no significant differences were observed in the type, extent and distribution of involved plaques between diabetic and non-diabetic patients.

  15. Volumetric evaluation of dual-energy perfusion CT by the presence of intrapulmonary clots using a 64-slice dual-source CT

    Okada, Munemasa; Nakashima, Yoshiteru; Kunihiro, Yoshie; Nakao, Sei; Matsunaga, Naofumi [Dept. of Radiology, Yamaguchi Univ. Graduate School of Medicine, Yamaguchi (Japan)], e-mail: radokada@yamaguchi-u.ac.jp; Morikage, Noriyasu [Medical Bioregulation Dept. of Organ Regulatory Surgery, Yamaguchi Univ. Graduate School of Medicine, Yamaguchi (Japan); Sano, Yuichi [Dept. of Radiology, Yamaguchi Univ. Hospital, Yamaguchi (Japan); Suga, Kazuyoshi [Dept. of Radiology, St Hills Hospital, Yamaguchi (Japan)

    2013-07-15

    Background: Dual-energy perfusion CT (DE{sub p}CT) directly represents the iodine distribution in lung parenchyma and low perfusion areas caused by intrapulmonary clots (IPCs) are visualized as low attenuation areas. Purpose: To evaluate if volumetric evaluation of DE{sub p}CT can be used as a predictor of right heart strain by the presence of IPCs. Material and Methods: One hundred and ninety-six patients suspected of having acute pulmonary embolism (PE) underwent DE{sub p}CT using a 64-slice dual-source CT. DE{sub p}CT images were three-dimensionally reconstructed with four threshold ranges: 1-120 HU (V{sub 120}), 1-15 HU (V{sub 15}), 1-10 HU (V{sub 10}), and 1-5 HU (V{sub 5}). Each relative ratio per V{sub 120} was expressed as the %V{sub 15}, %V{sub 10}, and %V{sub 5}. Volumetric data-sets were compared with D-dimer, pulmonary arterial (PA) pressure, right ventricular (RV) diameter, RV/left ventricular (RV/LV) diameter ratio, PA diameter, and PA/aorta (PA/Ao) diameter ratio. The areas under the ROC curves (AUCs) were examined for their relationship to the presence of IPCs. This study was approved by the local ethics committee. Results: PA pressure and D-dimer were significantly higher in the patients who had IPCs. In the patients with IPCs, V{sub 15}, V{sub 10}, V{sub 5}, %V{sub 15}, %V{sub 10}, and %V{sub 5} were also significantly higher than those without IPC (P = 0.001). %V{sub 5} had a better correlation with D-dimer (r = 0.30, P < 0.001) and RV/LV diameter ratio (r = 0.27, P < 0.001), and showed a higher AUC (0.73) than the other CT measurements. Conclusion: The volumetric evaluation by DE{sub p}CT had a correlation with D-dimer and RV/LV diameter ratio, and the relative ratio of volumetric CT measurements with a lower attenuation threshold might be recommended for the analysis of acute PE.

  16. Scheduling for dual-hop block-fading channels with two source-user pairs sharing one relay

    Zafar, Ammar

    2013-09-01

    In this paper, we maximize the achievable rate region of a dual-hop network with two sources serving two users independently through a single shared relay. We formulate the problem as maximizing the sum of the weighted long term average throughputs of the two users under stability constraints on the long term throughputs of the source-user pairs. In order to solve the problem, we propose a joint user-and-hop scheduling scheme, which schedules the first or second hop opportunistically based on instantaneous channel state information, in order to exploit multiuser diversity and multihop diversity gains. Numerical results show that the proposed joint scheduling scheme enhances the achievable rate region as compared to a scheme that employs multi-user scheduling on the second-hop alone. Copyright © 2013 by the Institute of Electrical and Electronic Engineers, Inc.

  17. Fire Source Localization Based on Distributed Temperature Sensing by a Dual-Line Optical Fiber System.

    Sun, Miao; Tang, Yuquan; Yang, Shuang; Li, Jun; Sigrist, Markus W; Dong, Fengzhong

    2016-01-01

    We propose a method for localizing a fire source using an optical fiber distributed temperature sensor system. A section of two parallel optical fibers employed as the sensing element is installed near the ceiling of a closed room in which the fire source is located. By measuring the temperature of hot air flows, the problem of three-dimensional fire source localization is transformed to two dimensions. The method of the source location is verified with experiments using burning alcohol as fire source, and it is demonstrated that the method represents a robust and reliable technique for localizing a fire source also for long sensing ranges. PMID:27275822

  18. Identification of the nitrate contamination sources of the Brusselian sands groundwater body (Belgium) using a dual-isotope approach

    Mattern, Samuel; Vanclooster, Marnik

    2010-05-01

    Knowledge of the groundwater pollution source is of primary importance to define appropriate remediation strategies. Yet, the identification of the contamination sources remains a complicated task. A dual isotope approach has been used to provide information for tracing sources of nitrate in water. In this study, we used the naturally occurring stable isotopic composition of groundwater nitrate (1) to evaluate the origin of nitrate in the Brussels sands aquifer (Belgium) and (2) to study the temporal dynamics of the isotope signature of groundwater nitrate in this region. Potential N sources sampled in the region, including e.g. ammonium and nitrate mineral fertilizers, sewage and rain, had isotopic signatures that fell within the corresponding typical ranges found in literature. Some of them however deviated from the isotopic ranges corresponding to typical N sources, illustrating the impact of processes affecting the isotopic signature of the nitrate sources. During a pluri-annual sampling campaign, groundwater samples were collected at 10 moments between June 2007 and February of 2009 over 9 monitoring stations located in the western part of the study area. The isotopic data time series suggest that, most of the time, N applied on the soil has been cycled in the soil by micro-organisms before leaching to the groundwater, while the isotopic data and the high nitrate concentrations strongly suggests that nitrate of the groundwater sampled in January 2008 principally originates from mineral fertilizers. The isotopic data measured at some of the 114 monitoring stations across the study area strongly suggests that the sources of nitrate are mineral fertilizers used in agriculture and golf courses, manure leaching from unprotected stockpiles in farms, domestic gardening practices, cesspools and probably cemeteries. Isotopic data are particularly helpful when associated with other information like historical data about monitoring stations, land use, chemical parameters

  19. Global Dual Sourcing: Tailored Base-Surge Allocation to Near- and Offshore Production

    Gad Allon; Jan A. Van Mieghem

    2010-01-01

    When designing a sourcing strategy in practice, a key task is to determine the average order rates placed to each source because that affects cost and supplier management. We consider a firm that has access to a responsive nearshore source (e.g., Mexico) and a low-cost offshore source (e.g., China). The firm must determine an inventory sourcing policy to satisfy random demand over time. Unfortunately, the optimal policy is too complex to allow a direct answer to our key question. Therefore, w...

  20. Xenon ventilation CT using dual-source and dual-energy technique in children with bronchiolitis obliterans: correlation of xenon and CT density values with pulmonary function test results

    Goo, Hyun Woo; Yang, Dong Hyun; Seo, Joon Beom; Chae, Eun Jin; Lee, Jeongjin [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Asan Medical Center, Songpa-gu, Seoul (Korea); Hong, Soo-Jong; Yu, Jinho; Kim, Byoung-Ju [University of Ulsan College of Medicine, Department of Pediatrics, Asan Medical Center, Seoul (Korea); Krauss, Bernhard [Siemens Medical Solutions AG-Computed Tomography, Forchheim (Germany)

    2010-09-15

    Xenon ventilation CT using dual-source and dual-energy technique is a recently introduced, promising functional lung imaging method. To expand its clinical applications evidence of additional diagnostic value of xenon ventilation CT over conventional chest CT is required. To evaluate the usefulness of xenon ventilation CT using dual-source and dual-energy technique in children with bronchiolitis obliterans (BO). Seventeen children (age 7-18 years; 11 boys) with BO underwent xenon ventilation CT using dual-source and dual-energy technique. Xenon and CT density values were measured in normal and hyperlucent lung regions on CT and were compared between the two regions. Volumes of hyperlucent regions and ventilation defects were calculated with thresholds determined by visual and histogram-based analysis. Indexed volumes of hyperlucent lung regions and ventilation defects were correlated with pulmonary function test results. Effective doses of xenon CT were calculated. Xenon (14.6 {+-} 6.4 HU vs 26.1 {+-} 6.5 HU; P < 0.001) and CT density (-892.8 {+-} 25.4 HU vs -812.3 {+-} 38.7 HU; P < 0.001) values were significantly lower in hyperlucent regions than in normal lung regions. Xenon and CT density values showed significant positive correlation for the entire lung in 16 children ({gamma} = 0.55 {+-} 0.17, P < 0.001 or =0.017) and for hyperlucent regions in 13 children ({gamma} = 0.44 {+-} 0.16, P < 0.001 or =0.001-0.019). Indexed volumes and volume percentages of hyperlucent lung regions and ventilation defects showed strong negative correlations with forced expiratory volume [FEV1, ({gamma} = -0.64-0.85, P {<=} 0.006)], FEV1/forced vital capacity [FVC, ({gamma} = -0.63-0.84, P {<=} 0.008)], and forced midexpiratory flow rate [FEF{sub 25-75}, ({gamma} = -0.68-0.88, P {<=} 0.002). Volume percentages of xenon ventilation defects (35.0 {+-} 16.4%)] were not significantly different from those of hyperlucent lung regions (38.2 {+-} 18.6%). However, mismatches between the

  1. Utilization of dual-source X-ray tomography for reduction of scanning time of wooden samples

    We present a novel dual-source/dual energy (DSCT/DECT) micro-tomography system including results of high-resolution DSCT reconstruction. The DSCT micro-tomography setup was designed as a multi-purpose X-ray imaging device equipped with two pairs of X-ray tubes and detectors in orthogonal arrangement with independent control of beam parameters. Both pairs (tube-detector) are mounted on a computer numerical control positioning system and can be independently set up to different geometries (e.g. with different magnification of each pair). In this work the simultaneous scanning of the object by two tube-detector pairs was used for approximately half reduction of tomography scanning time. The developed imaging procedure was applied for scanning of a wooden sample locally damaged during a semi-destructive test for assessment of wood quality. Prior to the tomography measurements the setup geometry was precisely adjusted in terms of magnification, horizontal and vertical tube-specimen-detector alignment of both pairs. DSCT measurements were carried out in sequence (2 × 90° for each tube) with identical 100μm image resolution. It was proven that the presented experimental setup combined with appropriate control technique significantly reduces tomography scanning time of materials with complex micro-structure

  2. Dual Solutions of MHD Boundary Layer Flow past an Exponentially Stretching Sheet with Non-Uniform Heat Source/Sink

    Raju CSK

    2016-01-01

    Full Text Available In this study we analyzed the momentum and heat transfer characteristics of MHD boundary layer flow over an exponentially stretching surface in porous medium in the presence of radiation, non-uniform heat source/sink, external pressure and suction/injection. Dual solutions are presented for both suction and injection cases. The heat transfer analysis is carried out for both prescribed surface temperature (PST and prescribed heat flux (PHF cases. The governing equations of the flow are transformed into system of nonlinear ordinary differential equations by using similarity transformation and solved numerically using bvp4c Matlab package. The impact of various non-dimensional governing parameters on velocity, temperature profiles for both PST and PHF cases, friction factor and rate of heat transfer is discussed and presented with the help of graphs and tables. Results indicate that dual solutions exist only for certain range of suction or injection parameters. It is also observed that the exponential parameter have tendency to increase the heat transfer rate for both PST and PHF cases.

  3. Why do premature newborn infants display elevated blood adenosine levels?

    Panfoli, Isabella; Cassanello, Michela; Bruschettini, Matteo; Colella, Marina; Cerone, Roberto; Ravera, Silvia; Calzia, Daniela; Candiano, Giovanni; Ramenghi, Luca

    2016-05-01

    Our preliminary data show high levels of adenosine in the blood of very low birth weight (VLBW) infants, positively correlating to their prematurity (i.e. body weight class). This prompted us to look for a mechanism promoting such impressive adenosine increase. We hypothesized a correlation with oxygen challenge. In fact, it is recognized that either oxygen lack or its excess contribute to the pathogenesis of the injuries of prematurity, such as retinopathy (ROP) and periventricular white matter lesions (PWMI). The optimal concentration of oxygen for resuscitation of VLBW infants is currently under revision. We propose that the elevated adenosine blood concentrations of VLBW infants recognizes two sources. The first could be its activity-dependent release from unmyelinated brain axons. Adenosine in this respect would be an end-product of the hypometabolic VLBW newborn unmyelinated axon intensely firing in response to the environmental stimuli consequent to premature birth. Adenosine would be eventually found in the blood due to blood-brain barrier immaturity. In fact, adenosine is the primary activity-dependent signal promoting differentiation of premyelinating oligodendrocyte progenitor cells (OPC) into myelinating cells in the Central Nervous System, while inhibiting their proliferation and inhibiting synaptic function. The second, would be the ecto-cellular ATP synthesized by the endothelial cell plasmalemma exposed to ambient oxygen concentrations due to premature breathing, especially in lung. ATP would be rapidly transformed into adenosine by the ectonucleotidase activities such as NTPDase I (CD39), and NT5E (CD73). An ectopic extra-mitochondrial aerobic ATP synthetic ability was reported in many cell plasma-membranes, among which endothelial cells. The potential implications of the cited hypotheses for the neonatology area would be great. The amount of oxygen administration for reviving of newborns would find a molecular basis for its assessment. VLBW

  4. Ultra-low-dose dual-source CT coronary angiography with high pitch: diagnostic yield of a volumetric planning scan and effects on dose reduction and imaging strategy

    Maurer, Martin; Hamm, B; Huppertz, A; Lembcke, A.

    2015-01-01

    OBJECTIVE To evaluate the role of an ultra-low-dose dual-source CT coronary angiography (CTCA) scan with high pitch for delimiting the range of the subsequent standard CTCA scan. METHODS 30 patients with an indication for CTCA were prospectively examined using a two-scan dual-source CTCA protocol (2.0 × 64.0 × 0.6 mm; pitch, 3.4; rotation time of 280 ms; 100 kV): Scan 1 was acquired with one-fifth of the tube current suggested by the automatic exposure control software [CareDose 4...

  5. Adenosine-induced activation of esophageal nociceptors.

    Ru, F; Surdenikova, L; Brozmanova, M; Kollarik, M

    2011-03-01

    Clinical studies implicate adenosine acting on esophageal nociceptive pathways in the pathogenesis of noncardiac chest pain originating from the esophagus. However, the effect of adenosine on esophageal afferent nerve subtypes is incompletely understood. We addressed the hypothesis that adenosine selectively activates esophageal nociceptors. Whole cell perforated patch-clamp recordings and single-cell RT-PCR analysis were performed on the primary afferent neurons retrogradely labeled from the esophagus in the guinea pig. Extracellular recordings were made from the isolated innervated esophagus. In patch-clamp studies, adenosine evoked activation (inward current) in a majority of putative nociceptive (capsaicin-sensitive) vagal nodose, vagal jugular, and spinal dorsal root ganglia (DRG) neurons innervating the esophagus. Single-cell RT-PCR analysis indicated that the majority of the putative nociceptive (transient receptor potential V1-positive) neurons innervating the esophagus express the adenosine receptors. The neural crest-derived (spinal DRG and vagal jugular) esophageal nociceptors expressed predominantly the adenosine A(1) receptor while the placodes-derived vagal nodose nociceptors expressed the adenosine A(1) and/or A(2A) receptors. Consistent with the studies in the cell bodies, adenosine evoked activation (overt action potential discharge) in esophageal nociceptive nerve terminals. Furthermore, the neural crest-derived jugular nociceptors were activated by the selective A(1) receptor agonist CCPA, and the placodes-derived nodose nociceptors were activated by CCPA and/or the selective adenosine A(2A) receptor CGS-21680. In contrast to esophageal nociceptors, adenosine failed to stimulate the vagal esophageal low-threshold (tension) mechanosensors. We conclude that adenosine selectively activates esophageal nociceptors. Our data indicate that the esophageal neural crest-derived nociceptors can be activated via the adenosine A(1) receptor while the placodes

  6. Dual isotope notch observer for isotope identification, assay and imaging with mono-energetic gamma-ray sources

    Barty, Christopher P.J.

    2013-02-05

    A dual isotope notch observer for isotope identification, assay and imaging with mono-energetic gamma-ray sources includes a detector arrangement consists of three detectors downstream from the object under observation. The latter detector, which operates as a beam monitor, is an integrating detector that monitors the total beam power arriving at its surface. The first detector and the middle detector each include an integrating detector surrounding a foil. The foils of these two detectors are made of the same atomic material, but each foil is a different isotope, e.g., the first foil may comprise U235 and second foil may comprise U238. The integrating detectors surrounding these pieces of foil measure the total power scattered from the foil and can be similar in composition to the final beam monitor. Non-resonant photons will, after calibration, scatter equally from both foils.

  7. Adenosine in inflammatory joint diseases

    Chan, E. S. L.; Fernandez, P.; Cronstein, B. N.

    2007-01-01

    Inflammatory joint diseases are a group of heterogeneous disorders with a variety of different etiologies and disease manifestations. However, there are features that are common to all of them: first, the recruitment of various inflammatory cell types that are attracted to involved tissues over the course of the disease process. Second, the treatments used in many of these diseases are commonly medications that suppress or alter immune function. The demonstration that adenosine has endogenous...

  8. Dual-source computed tomography: Estimation of radiation exposure of ECG-gated and ECG-triggered coronary angiography

    Ketelsen, Dominik [Department of Diagnostic and Interventional Radiology, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany)], E-mail: dominik.ketelsen@med.uni-tuebingen.de; Thomas, Christoph; Werner, Matthias; Luetkhoff, Marie H. [Department of Diagnostic and Interventional Radiology, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany); Buchgeister, Markus [Departments of Radiotherapy and Radiooncology, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany); Tsiflikas, Ilias; Reimann, Anja [Department of Diagnostic and Interventional Radiology, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany); Burgstahler, Christof [Department of Cardiology, University Hospital Tuebingen, Ottfried-Mueller-Strasse 10, 72076 Tuebingen (Germany); Brodoefel, Harald; Kopp, Andreas F.; Claussen, Claus D.; Heuschmid, Martin [Department of Diagnostic and Interventional Radiology, University Hospital Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany)

    2010-02-15

    Purpose: The aim of the study was to estimate radiation exposure of coronary calcium scoring and angiography using ECG-gated and ECG-triggered dual-source computed tomography. Materials and methods: An Alderson Rando phantom equipped with thermoluminescent dosimeters was used for all dose measurements. Effective dose was calculated according to ICRP 103. Radiation exposure was performed on a dual-source computed tomography (DSCT) scanner with standard protocols for calcium scoring (DSCT-Ca) and coronary angiography (DSCTA) at different heart rates (40-100 beats/min). Furthermore, a scanning protocol with ECG-triggering as well as a standard chest CT scan were evaluated. Results: Depending on gender, heart rate and ECG-pulsing, the effective dose of a complete cardiac DSCT (DSCT-Ca and DSCTA) scan varies from 10.2 to 32.6 mSv. The effective radiation dose increased significantly with lower heart rates (p < 0.035). ECG-pulsing reduced the radiation exposure significantly in DSCTA (p < 0.001). Due to breast tissue in the primary scan range, females' doses showed an increase up to 69.9% compared to males in scan protocols without ECG-pulsing. Prospective ECG-triggered DSCTA resulted in estimated effective doses from 2.8 mSv (males) to 4.1 mSv (females). Conclusion: The ECG-pulsing technique has proven its effectiveness to reduce effective dose in coronary CT angiography and is recommended for all patients with regular heart rates. The patient's heart rate influences the radiation exposure with a significant decrease at higher heart rates. Due to its lower dose, ECG-triggered DSCTA should be implemented for special indications, i.e. for diagnosis of pathologies of the aortic root and the ascending aorta.

  9. Dual-source 128-slice MDCT neck: Radiation dose and image quality estimation of three different protocols

    Purpose: To estimate the radiation dose and image quality of single-source (SSCT), high-pitch (HPCT), and dual-energy (DECT) protocols of a dual-source CT (DSCT) system for the examination of neck. Materials and methods: 180 patients were randomized to one of the three protocols: 60 patients (age: 55.4 ± 12 years; range: 44–84 years) were examined with a SSCT, other 60 (59.5 ± 16.4years; R: 40–85) with HPCT, and the last 60 (61.1 ± 14.9 years; R: 47–84) were examined with a DECT protocol. All examinations were performed using a DSCT system. The used protocols: Group-1 (SSCT: 120 kV; effective mAs: 185.4 ± 17.7), Group-2 (HPCT: 120 kV; eff. mAs: 97.7 ± 11.8), and Group-3 (DECT: 80 kV/140 kV with tin-filter; eff. mAs: 248.5 ± 25.7; 187 ± 21.2). A 100 ml iomeprol non-ionic contrast material was injected in to the patients during examination. Results: Insignificant results were yielded regarding SNR and CNR between the groups (group-1 vs. 2: 0.3125, group-1 vs. 0.6W: 0.6875, group-2 vs. 0.6W: 0.3125), except DECT-80 (group-1 vs. 80 kV: 0.04289, group-2 vs. 80 kV: 0.025, group-0.6W vs.80 kV: 0.04567) and 140 kV data, moreover, qualitative analysis yielded the same results. Mean effective-dose was significantly lower (p < 0.05) in group-2 (1.06 ± 0.16 mSv) compared to group-1 (2.05 ± 0.22 mSv) or group-3 (1.76 ± 0.2 mSv). Single- and dual-energy comparison showed a significant difference (group-1 vs. 3: p = 0.00001 and group-2 vs. 3: p = 0.00001) for CTDIvol (percent difference: 16%, 64%) or DLP (PD: 15.5%, 50.5%). Conclusion: Quantitative and qualitative analysis showed similar results for SSCT, HPCT, and DECT-0.6W datasets regarding quality. HPCT yielded lower dose compared to other groups, however, the DECT achieved a lower and significant dose difference from the SSCT protocol. HPCT and DECT can be used with similar image quality and lower radiation dose compared to SSCT for the scans and can be utilized to various clinical advantages

  10. Adenosine and the adenosine A2A receptor agonist, CGS21680, upregulate CD39 and CD73 expression through E2F-1 and CREB in regulatory T cells isolated from septic mice.

    Bao, Rui; Shui, Xianqi; Hou, Jiong; Li, Jinbao; Deng, Xiaoming; Zhu, Xiaoyan; Yang, Tao

    2016-09-01

    The number of regulatory T cells (Treg cells) and the expression of ectonucleoside triphosphate diphosphohydrolase 1 (ENTPD1; also known as CD39) and 5'-ectonucleotidase (NT5E; also known as CD73) on the Treg cell surface are increased during sepsis. In this study, to determine the factors leading to the high expression of CD39 and CD73, and the regulation of the CD39/CD73/adenosine pathway in Treg cells under septic conditions, we constructed a mouse model of sepsis and separated the Treg cells using a flow cytometer. The Treg cells isolated from the peritoneal lavage and splenocytes of the mice were treated with adenosine or the specific adenosine A2A receptor agonist, CGS21680, and were transfected with specific siRNA targeting E2F transcription factor 1 (E2F-1) or cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB), which are predicted transcription regulatory factors of CD39 or CD73. The regulatory relationships among these factors were then determined by western blot analysis and dual-luciferase reporter assay. In addition, changes in adenosine metabolism were measured in the treated cells. The results revealed that adenosine and CGS21680 significantly upregulated CD39 and CD73 expression (PTreg cell surface during sepsis. Adenosine and its A2A receptor agonist served as the signal transducer factors of the CD39/CD73/adenosine pathway, accelerating adenosine generation. Our study may benefit further research on adenosine metabolism for the treatment of sepsis. PMID:27430240

  11. Global dual sourcing and order smoothing: the impact of capacity and leadtimes

    Boute, Robert; Van Mieghem, Jan Albert

    2015-01-01

    After decades of offshoring production across the world, companies are rethinking their global networks. Local sourcing is receiving more attention, but it remains challenging to balance the offshore sourcing cost advantage against the increased inventories, because of its longer lead time, and against the cost and (volume) flexibility of each source’s capacity. To guide strategic allocation in this global network decision, this paper establishes reasonably simple prescriptions that capture t...

  12. Role of extracellular adenosine in Drosophila

    FENCKOVÁ, Michaela

    2011-01-01

    This thesis describes several aspects of the role for extracellular adenosine in Drosophila. Reverse genetic, molecular and microscopic methods together with the most forefront Drosophila research techniques have been applied to elucidate the role of adenosine signaling in the regulation of development, physiology and metabolism of Drosophila larvae. The thesis helps to establish the model for extracellular adenosine as a stress-signal for the release of energy stores. It also describes the e...

  13. A dual neutron/gamma source for the Fissmat Inspection for Nuclear Detection (FIND) system.

    Doyle, Barney Lee (Sandia National Laboratories, Albuquerque, NM); King, Michael; Rossi, Paolo (Sandia National Laboratories, Albuquerque, NM); McDaniel, Floyd Del (Sandia National Laboratories, Albuquerque, NM); Morse, Daniel Henry; Antolak, Arlyn J.; Provencio, Paula Polyak (Sandia National Laboratories, Albuquerque, NM); Raber, Thomas N.

    2008-12-01

    Shielded special nuclear material (SNM) is very difficult to detect and new technologies are needed to clear alarms and verify the presence of SNM. High-energy photons and neutrons can be used to actively interrogate for heavily shielded SNM, such as highly enriched uranium (HEU), since neutrons can penetrate gamma-ray shielding and gamma-rays can penetrate neutron shielding. Both source particles then induce unique detectable signals from fission. In this LDRD, we explored a new type of interrogation source that uses low-energy proton- or deuteron-induced nuclear reactions to generate high fluxes of mono-energetic gammas or neutrons. Accelerator-based experiments, computational studies, and prototype source tests were performed to obtain a better understanding of (1) the flux requirements, (2) fission-induced signals, background, and interferences, and (3) operational performance of the source. The results of this research led to the development and testing of an axial-type gamma tube source and the design/construction of a high power coaxial-type gamma generator based on the {sup 11}B(p,{gamma}){sup 12}C nuclear reaction.

  14. Numerical simulation of a dual-source supersonic plasma jet expansion process: continuum approach

    Expanding thermal plasma (ETP) is a versatile technology for thin film deposition process with directional plasma flux and high deposition rates. This process involves expansion of supersonic plasma jets through a steep pressure ratio into a chamber maintained at near vacuum. Usually the plasma jets deviate from chemical and thermal equilibrium and the continuum approach is insufficient to describe the phenomena. In the current work, the continuum approach based Navier-Stokes equations have been implemented to study and understand the jet expansion process in a typical dual-arc plasma deposition reactor. The numerical predictions have been compared against in-house experimental data obtained by thermocouple measurements. For the range of back pressures (6-200 Pa) considered, it was observed that the jet core is supersonic and transitions to a subsonic zone downstream without the formation of any Mach disc for the prevalent operating parameters. Indications of thick and smeared barrel shocks were however observed in the computed flow-thermal fields. The modelled fluid was assumed to be a perfect gas with temperature dependent specific heats, thermal conductivity and viscosity coefficients, with constant Prandtl number of order unity. The radial spreads of the jets increase with increasing pressure ratio thus leading to enhanced interactions within reduced distances downstream of the nozzle exit. The jet core Mach number also increases, but moderately, with decreasing backpressure. It is concluded that within reasonable accuracy, continuum approach based calculations are able to capture most of the important phenomena involved in compressible, high-temperature, supersonic jet expansion processes which are essential in designing chambers relevant to the mentioned processes

  15. Effect of Heart Rate and Coronary Calcification on the Diagnostic Accuracy of the Dual-Source CT Coronary Angiography in Patients with Suspected Coronary Artery Disease

    MENG, LINGDONG; CUI, LIANQUN; Cheng, Yuntao; Wu, Xiaoyan; Tang, Yuansheng; Wang, Yong; Xu, Fayun

    2009-01-01

    Objective To evaluate the diagnostic accuracy of a dual-source computed tomography (DSCT) coronary angiography, with a particular focus on the effect of heart rate and calcifications. Materials and Methods One hundred and nine patients with suspected coronary disease were divided into 2 groups according to a mean heart rate ( 400). Next, the effect of heart rate and calcification on th...

  16. Reduced striatal ecto-nucleotidase activity in schizophrenia patients supports the “adenosine hypothesis”

    Aliagas, Elisabet; Villar-Menéndez, Izaskun; Sévigny, Jean; Roca, Mercedes; Romeu, Miriam; Ferrer, Isidre; Martín-Satué, Mireia; Barrachina, Marta

    2013-01-01

    Schizophrenia (SZ) is a major chronic neuropsychiatric disorder characterized by a hyperdopaminergic state. The hypoadenosinergic hypothesis proposes that reduced extracellular adenosine levels contribute to dopamine D2 receptor hyperactivity. ATP, through the action of ecto-nucleotidases, constitutes a main source of extracellular adenosine. In the present study, we examined the activity of ecto-nucleotidases (NTPDases, ecto-5′-nucleotidase, and alkaline phosphatase) in the postmortem putame...

  17. Radio-chromatographic determination of plasmatic adenosine deaminase (A.D.)

    We were able, by using a radio-chromatographic method, to measure an adenosine deaminase activity in normal human heparinized platelet-poor plasma, which can degrade 0.016 μM adenosine. This activity suppressed by heating 56 C for 30 minutes is inhibited by high concentrations of urea and is proportional to the amount of plasma, source of enzyme, in the systems. (authors)

  18. Energy Efficient Routing Algorithms in Dynamic Optical Core Networks with Dual Energy Sources

    Wang, Jiayuan; Fagertun, Anna Manolova; Ruepp, Sarah Renée; Dittmann, Lars

    This paper proposes new energy efficient routing algorithms in optical core networks, with the application of solar energy sources and bundled links. A comprehensive solar energy model is described in the proposed network scenarios. Network performance in energy savings, connection blocking...

  19. DUHOCAMIS: a dual hollow cathode ion source for metal ion beams.

    Zhao, W J; Müller, M W O; Janik, J; Liu, K X; Ren, X T

    2008-02-01

    In this paper we describe a novel ion source named DUHOCAMIS for multiply charged metal ion beams. This ion source is derived from the hot cathode Penning ion gauge ion source (JINR, Dubna, 1957). A notable characteristic is the modified Penning geometry in the form of a hollow sputter electrode, coaxially positioned in a compact bottle-magnetic field along the central magnetic line of force. The interaction of the discharge geometry with the inhomogeneous but symmetrical magnetic field enables this device to be operated as hollow cathode discharge and Penning discharge as well. The main features of the ion source are the very high metal ion efficiency (up to 25%), good operational reproducibility, flexible and efficient operations for low charged as well as highly charged ions, compact setup, and easy maintenance. For light ions, e.g., up to titanium, well-collimated beams in the range of several tens of milliamperes of pulsed ion current (1 ms, 10/s) have been reliably performed in long time runs. PMID:18315181

  20. Closing in on the K Edge : Coronary CT Angiography at 100, 80, and 70 kV-Initial Comparison of a Second-versus a Third-Generation Dual-Source CT System

    Meyer, Mathias; Haubenreisser, Holger; Schoepf, U. Joseph; Vliegenthart, Rozemarijn; Leidecker, Christianne; Allmendinger, Thomas; Lehmann, Ralf; Sudarski, Sonja; Borggrefe, Martin; Schoenberg, Stefan O.; Henzler, Thomas

    2014-01-01

    Purpose: To prospectively evaluate radiation and contrast medium requirements for performing high-pitch coronary computed tomographic (CT) angiography at 70 kV using a third-generation dual-source CT system in comparison to a second-generation dual-source CT system. Materials and Methods: All patien

  1. Active induction balance method for metal detector sensing head utilizing transmitter-bucking and dual current source

    A central problem in a design of frequency domain electromagnetic induction sensors used in landmine detection is an effective suppression of a direct inductive coupling between the transmitter and the receiver coil (induction balance, IB). In sensing heads based on the transmitter-bucking configuration, IB is achieved by using two concentric transmitter coils with opposing exciter fields in order to create a central magnetic cavity for the receiver coil. This design has numerous advantages over other IB methods in terms of detection sensitivity, spatial resolution, sensor dimensions and suitability for model-based measurements. However, very careful design and precise sensing head geometry are required if a single excitation source is used for driving both transmitter coils. In this paper we analyze the IB sensitivity to small perturbations of geometrical properties of coils. We propose a sensor design with dual current source and active induction balance scheme which overcomes the limitations of geometry-based balancing and potentially provides more efficient compensation of soil effects.

  2. A Dirichlet-integral based dual-access collocation-kernel approach to point-source gravity-field modleing

    Rufty, A

    2006-01-01

    Problems in $\\mathbb{R}^3$ are addressed where the scalar potential of an associated vector field satisfies Laplace's equation in some unbounded external region and is to be approximated by unknown (point) sources contained in the complimentary subregion. Two specific field geometries are considered: $\\mathbb{R}^3$ half-space and the exterior of an $\\mathbb{R}^3$ sphere, which are the two standard settings for geophysical and geoexploration gravitational problems. For these geometries it is shown that a new type of kernel space exists, which is labeled a Dirichlet-integral dual-access collocation-kernel space (DIDACKS) and that is well suited for many applications. The DIDACKS examples studied are related to reproducing kernel Hilbert spaces and they have a replicating kernel (as opposed to a reproducing kernel) that has the ubiquitous form of the inverse of the distance between a field point and a corresponding source point. Underpinning this approach are three basic mathematical relationships of general int...

  3. 基于双源采购的供应应急管理分析%Analysis on Supply Emergency Management Based on Dual-Source

    张文杰; 骆建文

    2013-01-01

    The problem about manufacturer's supply emergency management strategy under emergencies was studied. Based on single-source, the effects of two different strategies including risky dual-source and mixed dual-source on responding to supply disruption risk were analyzed. The optimal ordering decision and expected profit of the manufacturer in two different procurement strategies were compared, and the factors that have the impact on the manufacturer's choice of emergency strategy were analyzed. Finally, some numerical examples were used to demonstrate the impact of supply disruption probability on the procurement decision and expected profit of the manufacturer. It is shown that dual-source strategy is better than single-source in the prevention of the risk of supply disruptions. The total ordered quantity by the manufacturer in mixed dual-source is equal to that of single-source, but less than that of risky dual-source. In the case of mixed dual-source strategy, the manufacturer will increase the use of reliable supplier as the disruption probability increases, even though bear a higher purchase cost.%研究了突发事件环境下制造商的供应应急管理策略问题.以单源采购策略为基准,分析了风险双源采购和混合双源采购2种不同应急策略防范突发事件导致的供应中断风险的有效性,比较了不同双源采购策略下制造商的最优订货和期望利润,分析了制造商对供应应急策略选择的影响因素.研究表明,双源采购策略在防范供应中断风险方面优于单源采购,制造商在单源采购与混合双源采购情形下的总订货量相等,但小于风险双源采购情形.混合双源采购时,随着风险供应商中断概率的增加,尽管要承担更高的采购成本,制造商仍将增加对可靠供应商的使用.

  4. First experience with single-source dual-energy computed tomography in six patients with acute arthralgia: a feasibility experiment using joint aspiration as a reference

    Diekhoff, Torsten; Kiefer, Tobias; Hamm, Bernd; Hermann, Kay-Geert A. [Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Freie Universitaet Berlin, Department of Radiology, Berlin (Germany); Ziegeler, Katharina; Feist, Eugen [Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Freie Universitaet Berlin, Department of Rheumatology and Clinical Immunology, Berlin (Germany); Mews, Juergen [Toshiba Medical Systems Europe, BV, Zoetermeer (Netherlands)

    2015-11-15

    Dual-energy computed tomography (DECT) is an emerging imaging technique for examining patients with suspected gout. Single-source dual-energy CT (S-DECT) is a new way of obtaining DECT information on conventional CT scanners rather than using special dual-source CT systems. We tested the feasibility of S-DECT (320-row CT; Aquilion ONE, Toshiba Medical Systems, Otawara, Japan) in 6 patients (5 men, 1 woman; mean age 61.3, range 48 to 69 years) with acute arthralgia and suspected gout, and compared the S-DECT findings with the results of joint aspiration. Three patients had a diagnosis of gouty arthritis with negatively birefringent crystals in synovial fluid, in addition to gouty tophi in S-DECT. Three patients had no detectable crystals by polarization microscopy and no tophi on DECT. Their final diagnoses were rheumatoid arthritis, activated osteoarthritis, and septic arthritis in one case each. This initial experience suggests that S-DECT might be a valuable alternative to dual-source CT. Hence, more patients may benefit from its additional diagnostic abilities in the future. (orig.)

  5. Energy Management of Dual-Source Propelled Electric Vehicle using Fuzzy Controller Optimized via Genetic Algorithm

    Khoobi, Saeed; Halvaei, Abolfazl; Hajizadeh, Amin

    2016-01-01

    EV relies too much on the expert experience and it may lead to sub-optimal performance. This paper develops an optimized fuzzy controller using genetic algorithm (GA) for an electric vehicle equipped with two power bank including battery and super-capacitor. The model of EV and optimized fuzzy......Energy and power distribution between multiple energy sources of electric vehicles (EVs) is the main challenge to achieve optimum performance from EV. Fuzzy inference systems are powerful tools due to nonlinearity and uncertainties of EV system. Design of fuzzy controllers for energy management of...

  6. Tracing the Nitrate Sources of the Yili River in the Taihu Lake Watershed: A Dual Isotope Approach

    Haiao Zeng

    2014-12-01

    Full Text Available As the third largest freshwater lake in China, Taihu Lake has experienced severe cyanobacterial blooms and associated water quality degradation in recent decades, threatening the human health and sustainable development of cities in the watershed. The Yili River is a main river of Taihu Lake, contributing about 30% of the total nitrogen load entering the lake. Tracing the nitrate sources of Yili River can inform the origin of eutrophication in Taihu Lake and provide hints for effective control measures. This paper explored the nitrate sources and cycling of the Yili River based on dual nitrogen (δ15N and oxygen (δ18O isotopic compositions. Water samples collected during both the wet and dry seasons from different parts of the Yili River permitted the analysis of the seasonal and spatial variations of nitrate concentrations and sources. Results indicated that the wet season has higher nitrate concentrations than the dry season despite the stronger dilution effects, suggesting a greater potential of cyanobacterial blooms in summer. The δ15N-NO3− values were in the range of 4.0‰–14.0‰ in the wet season and 4.8‰–16.9‰ in dry, while the equivalent values of δ18O were 0.5‰–17.8‰ and 3.5‰–15.6‰, respectively. The distribution of δ15N-NO3− and δ18O-NO3− indicated that sewage and manure as well as fertilizer and soil organic matter were the major nitrate sources of the Yili River. Atmospheric deposition was an important nitrate source in the upper part of Yili River but less so in the middle and lower reaches due to increasing anthropogenic contamination. Moreover, there was a positive relationship between δ18O-NO3− and δ15N-NO3− in the wet season, indicating a certain extent of denitrification. In contrast, the δ18O-δ15N relationship in the dry season was significantly negative, suggesting that the δ15N and δ18O values were determined by a mixing of different nitrate sources.

  7. Assessment of aortic stenosis after aortic valve replacement. Comparative evaluation of dual-source CT and echocardiography

    Purpose: To prospectively evaluate whether planimetric measurements of aortic valve area (AVA) with dual-source computed tomography (DSCT) correlate with measurements obtained by echocardiography and to correlate the amount of calcification of the aortic valve with AVA in a group of patients after aortic valve replacement. Materials and Method: 23 patients underwent dual-source computed tomography (DSCT) of the heart (Somatom Definition, Siemens Medical Solutions, Forchheim, Germany), without heart rate control (heart rate 52-113 beats/minute). All patients had undergone aortic valve replacement (homografts, mean time after surgery: 7±3 years). The AVA of the transplanted aortic valve graft was measured planimetrically by means of DSCT and compared with echocardiography as a standard of reference, to exclude post-surgical restenosis of the valve. Maximum AVA in systole planimetrically measured with CT was compared with calculated AVA values determined with the continuity equation, using transvalvular pressure gradients. The amount of calcification of the aortic valve was quantified and correlated (Spearman's R) with the AVA. To assess intra- and inter-reader reproducibility, the DCST data was re-analyzed by two readers 4 weeks after the initial review. Results: All DSCT datasets were of diagnostic image quality concerning valve depiction. The mean AVA as measured by DSCT was 2.7±0.9 cm2 compared to 1.8±0.5 cm2 by echocardiography (p<0.05). The planimetric evaluation of the CT data as compared to results of echocardiography showed a significant correlation of the results (Pearson's correlation coefficient R=0.78, p<0.001). Intra- and inter-reader reproducibility was good with intra-class correlation coefficients of 0.86 and 0.81, respectively (p<0.001). There was a significant negative correlation between the amount of aortic valve calcification and AVA as measured by echocardiography (R=-0.42; p<0.05) and as measured by DSCT (R=-0.67; p=0.001). (orig.)

  8. Optimal image reconstruction phase at low and high heart rates in dual-source CT coronary angiography.

    Araoz, Philip A; Kirsch, Jacobo; Primak, Andrew N; Braun, Natalie N; Saba, Osama; Williamson, Eric E; Harmsen, W Scott; Mandrekar, Jayawant N; McCollough, Cynthia H

    2009-12-01

    The purpose of this study was to determine the cardiac phase having the highest coronary sharpness for low and high heart rate patients scanned with dual source CT (DSCT) and to compare coronary image sharpness over different cardiac phases. DSCT coronary CT scans for 30 low heart rate (70 bpm) patients were reconstructed into different cardiac phases, starting at 30% and increasing at 5% increments until 70%. A blinded observer graded image sharpness per coronary segment, from which sharpness scores were produced for the right (RCA), left main (LM), left anterior descending (LAD), and circumflex (Cx) coronary arteries. For each coronary artery, the phase with maximal image sharpness was identified with repeated measures analysis of variance. Comparison of coronary sharpness between low and high heart rate patients was made using generalized estimating equations. For low heart rates the highest sharpness scores for all four vessels (RCA, LM, LAD, and Cx) were at the 65 or 70% phase, which are end-diastolic cardiac phases. For high heart rates the highest sharpness scores were between the 35 and 45% phases, which are end-systolic phases. Low heart rate patients had higher coronary sharpness at most cardiac phases; however, patients with high heart rates had higher coronary sharpness in the 45% phase for all four vessels (P < 0.0001). Using DSCT scanning, optimal image sharpness is obtained in end-diastole at low heart rates and in end-systole in high heart rates. PMID:19669664

  9. Detection of special nuclear material from delayed neutron emission induced by a dual-particle monoenergetic source

    Mayer, M.; Nattress, J.; Jovanovic, I.

    2016-06-01

    Detection of unique signatures of special nuclear materials is critical for their interdiction in a variety of nuclear security and nonproliferation scenarios. We report on the observation of delayed neutrons from fission of uranium induced in dual-particle active interrogation based on the 11B(d,n γ)12C nuclear reaction. Majority of the fissions are attributed to fast fission induced by the incident quasi-monoenergetic neutrons. A Li-doped glass-polymer composite scintillation neutron detector, which displays excellent neutron/γ discrimination at low energies, was used in the measurements, along with a recoil-based liquid scintillation detector. Time-dependent buildup and decay of delayed neutron emission from 238U were measured between the interrogating beam pulses and after the interrogating beam was turned off, respectively. Characteristic buildup and decay time profiles were compared to the common parametrization into six delayed neutron groups, finding a good agreement between the measurement and nuclear data. This method is promising for detecting fissile and fissionable materials in cargo scanning applications and can be readily integrated with transmission radiography using low-energy nuclear reaction sources.

  10. Tetralogy of Fallot Cardiac Function Evaluation and Intelligent Diagnosis Based on Dual-Source Computed Tomography Cardiac Images.

    Cai, Ken; Rongqian, Yang; Li, Lihua; Xie, Zi; Ou, Shanxing; Chen, Yuke; Dou, Jianhong

    2016-05-01

    Tetralogy of Fallot (TOF) is the most common complex congenital heart disease (CHD) of the cyanotic type. Studies on ventricular functions have received an increasing amount of attention as the development of diagnosis and treatment technology for CHD continues to advance. Reasonable options for imaging examination and accurate assessment of preoperative and postoperative left ventricular functions of TOF patients are important in improving the cure rate of TOF radical operation, therapeutic evaluation, and judgment prognosis. Therefore, with the aid of dual-source computed tomography (DSCT), cardiac images with high temporal resolution and high definition, we measured the left ventricular time-volume curve using image data and calculating the left ventricular function parameters to conduct the preliminary evaluation on TOF patients. To comprehensively evaluate the cardiac function, the segmental ventricular wall function parameters were measured, and the measurement results were mapped to a bull's eye diagram to realize the standardization of segmental ventricular wall function evaluation. Finally, we introduced a new clustering method based on auto-regression model parameters and combined this method with Euclidean distance measurements to establish an intelligent diagnosis of TOF. The results of this experiment show that the TOF evaluation and the intelligent diagnostic methods proposed in this article are feasible. PMID:26496001

  11. Comparison of diagnostic accuracy of dual-source CT and conventional angiography in detecting congenital heart diseases

    Cardiac dual-source computed tomography (DSCT) is primarily used for coronary arteries. There are limited studies about the application of DSCT for congenital heart diseases. The aim of this study was to determine the diagnostic value of DSCT in the cardiac anomalies. The images of DSCTs and conventional angiographies of 36 patients (21 male; mean age: 8.5 month) with congenital heart diseases were reviewed and the parameters of diagnostic value of these methods were compared. Cardiac surgery was the gold standard. A total of 105 cardiac anomalies were diagnosed at surgery. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of DSCT were 98.25%, 97.9%, 98.1%, 99.07%, and 98.2%, respectively. The corresponding values of angiography were 95.04%, 98.7%, 97.8%, 98.1%, and 98%, respectively. Only one atrial septal defect (ASD) and two patent ductus arteriosus (PDA) were missed by DSCT. Angiography missed two ASD and two PDA. DSCT also provided important additional findings (n=35) about the intrathoracic or intraabdominal organs. DSCT is a highly accurate diagnostic modality for congenital heart diseases, obviating the need for invasive modalities. Beside its noninvasive nature, the advantage of DSCT over the angiography is its ability to provide detailed anatomical information about the heart, vessels, lungs and intraabdominal organs

  12. Image quality analysis to reduce dental artifacts in head and neck imaging with dual-source computed tomography

    Ketelsen, D.; Werner, M.K.; Thomas, C.; Tsiflikas, I.; Reimann, A.; Claussen, C.D.; Heuschmid, M. [Tuebingen Univ. (Germany). Abt. fuer Diagnostische und Interventionelle Radiologie; Koitschev, A. [Tuebingen Univ. (Germany). Abt. fuer Hals-Nasen-Ohrenheilkunde

    2009-01-15

    Purpose: Important oropharyngeal structures can be superimposed by metallic artifacts due to dental implants. The aim of this study was to compare the image quality of multiplanar reconstructions and an angulated spiral in dual-source computed tomography (DSCT) of the neck. Materials and Methods: Sixty-two patients were included for neck imaging with DSCT. MPRs from an axial dataset and an additional short spiral parallel to the mouth floor were acquired. Leading anatomical structures were then evaluated with respect to the extent to which they were affected by dental artifacts using a visual scale, ranging from 1 (least artifacts) to 4 (most artifacts). Results: In MPR, 87.1 % of anatomical structures had significant artifacts (3.12 {+-} 0.86), while in angulated slices leading anatomical structures of the oropharynx showed negligible artifacts (1.28 {+-} 0.46). The diagnostic growth due to primarily angulated slices concerning artifact severity was significant (p < 0.01). Conclusion: MPRs are not capable of reducing dental artifacts sufficiently. In patients with dental artifacts overlying the anatomical structures of the oropharynx, an additional short angulated spiral parallel to the floor of the mouth is recommended and should be applied for daily routine. As a result of the static gantry design of DSCT, the use of a flexible head holder is essential. (orig.)

  13. Detection of Special Nuclear Material from Delayed Neutron Emission Induced by a Dual-Particle Monoenergetic Source

    Mayer, Michael F.; Nattress, J.; Jovanovic , I

    2016-06-30

    Detection of unique signatures of special nuclear materials is critical for their interdiction in a variety of nuclear security and nonproliferation scenarios. We report on the observation of delayed neutrons from fission of uranium induced in dual-particle active interrogation based on the 11B(d,n gamma)12C nuclear reaction. Majority of the fissions are attributed to fast fission induced by the incident quasi-monoenergetic neutrons. A Li-doped glass–polymer composite scintillation neutron detector, which displays excellent neutron/γ discrimination at low energies, was used in the measurements, along with a recoil-based liquid scintillation detector. Time- dependent buildup and decay of delayed neutron emission from 238U were measured between the interrogating beam pulses and after the interrogating beam was turned off, respectively. Characteristic buildup and decay time profiles were compared to the common parametrization into six delayed neutron groups, finding a good agreement between the measurement and nuclear data. This method is promising for detecting fissile and fissionable materials in cargo scanning applications and can be readily integrated with transmission radiography using low-energy nuclear reaction sources.

  14. Systolic prospectively ECG-triggered dual-source CT angiography for evaluation of the coronary arteries in heart transplant recipients

    Bastarrika, Gorka [Clinica Universidad de Navarra, Cardiac Imaging Unit, Pamplona (Spain); Clinica Universidad de Navarra, Department of Radiology, Pamplona (Spain); Broncano, Jordi; Arraiza, Maria; Simon-Yarza, Isabel; Pueyo, Jesus C.; Zubieta, Jose L. [Clinica Universidad de Navarra, Department of Radiology, Pamplona (Spain); Azcarate, Pedro M. [Clinica Universidad de Navarra, Cardiac Imaging Unit, Pamplona (Spain); Clinica Universidad de Navarra, Department of Cardiology, Pamplona (Spain); Levy Praschker, Beltran G.; Rabago, Gregorio [Clinica Universidad de Navarra, Department of Cardiovascular Surgery, Pamplona (Spain)

    2011-09-15

    To assess feasibility, image quality, and radiation dose of prospectively ECG-triggered coronary CT angiography (CTA) in orthotopic heart transplant (OHT) recipients. 47 consecutive OHT recipients (40 men, mean age 62.1{+-}10.9 years, mean heart rate 86.3{+-}14.4 bpm) underwent dual-source CTA to rule out coronary allograft vasculopathy in a prospectively ECG-triggered mode with data acquisition during 35% to 45% of the cardiac cycle. Two independent observers blindly assessed image quality on a per-segment and per-vessel basis using a four-point scale (1-excellent, 4-not evaluable). Scores 1-3 were considered acceptable for diagnosis. Multivariate analysis was performed to evaluate differences between image quality scores obtained at different reconstruction intervals. Effective radiation doses were calculated. 671 coronary segments were evaluated. Interobserver agreement on the image quality was {kappa}=0.75. Diagnostic image quality was observed in 93.9%, 95.5% and 93.3% of the segments at 35%, 40% and 45% reconstruction intervals. Mean image quality score was 1.5{+-}0.7 for the entire coronary tree, 1.4{+-}0.7 for the RCA, 1.6{+-}0.8 for the LCA and 1.6{+-}0.7 for the Cx at the best reconstruction interval. Estimated mean radiation dose was 4.5{+-}1.2 mSv. Systolic prospectively ECG-triggered CTA allows diagnostic image quality coronary angiograms in OHT recipients at low radiation doses. (orig.)

  15. Image quality analysis to reduce dental artifacts in head and neck imaging with dual-source computed tomography

    Purpose: Important oropharyngeal structures can be superimposed by metallic artifacts due to dental implants. The aim of this study was to compare the image quality of multiplanar reconstructions and an angulated spiral in dual-source computed tomography (DSCT) of the neck. Materials and Methods: Sixty-two patients were included for neck imaging with DSCT. MPRs from an axial dataset and an additional short spiral parallel to the mouth floor were acquired. Leading anatomical structures were then evaluated with respect to the extent to which they were affected by dental artifacts using a visual scale, ranging from 1 (least artifacts) to 4 (most artifacts). Results: In MPR, 87.1 % of anatomical structures had significant artifacts (3.12 ± 0.86), while in angulated slices leading anatomical structures of the oropharynx showed negligible artifacts (1.28 ± 0.46). The diagnostic growth due to primarily angulated slices concerning artifact severity was significant (p < 0.01). Conclusion: MPRs are not capable of reducing dental artifacts sufficiently. In patients with dental artifacts overlying the anatomical structures of the oropharynx, an additional short angulated spiral parallel to the floor of the mouth is recommended and should be applied for daily routine. As a result of the static gantry design of DSCT, the use of a flexible head holder is essential. (orig.)

  16. Diagnostic accuracy of dual-source CT coronary angiography: The effect of average heart rate, heart rate variability, and calcium score in a clinical perspective

    Background: Dual-source CT coronary angiography (CTCA) has been used to detect coronary artery disease; however, the factors with potential to affect its diagnostic accuracy remain to be defined. Purpose: To prospectively evaluate the accuracy of dual-source CTCA in diagnosing coronary artery stenosis according to conventional coronary angiography (CAG), and the effect of average heart rate, heart rate variability, and calcium score on the accuracy of CTCA. Material and Methods: A total of 113 patients underwent both dual-source CTCA and CAG. The results were used to evaluate the findings in dual-source CTCA to assess the accuracy in the diagnosis of =50% (significant stenosis) and >75% (severe stenosis) of coronary artery according to those by CAG. Patients were divided into subgroups according to their heart rate (HR), HR variability (HRV), and calcium score, and the accuracy of CTCA was further evaluated. The chi-square test was used to analyze the difference in sensitivity and specificity for the detection of =50% and >75% coronary stenosis among subgroups. The generalized estimation equation method was used in per-vessel analysis to adjust for within-patient correlation. Results: In all, 113 patients had 338 vessels and 1661 segments evaluated by CAG. Dual-source CTCA displayed 1527 segments (91.9%). Among them, 1468 segments (calcium score by CAG score 1, n=1018; score 2, n=270; score 3, n=180) were assessable in CTCA. On a per-patient analysis, the sensitivity and specificity of CTCA were 93.9% and 93.5% for significant stenosis and 86.9% and 98.1% for severe stenosis. On a per-vessel basis, the sensitivity and specificity were 90.2% and 97.1% for significant and 83.3% and 98.1% for severe stenosis. On a per-segment analysis, the sensitivity and specificity were 90.2% and 97.1% for significant and 83.3% and 98.1% for severe stenosis. Average HR had no effect on the sensitivity and specificity of CTCA (P>0.05); whereas HRV and calcium score had some effect on

  17. Automated attenuation-based tube voltage selection for body CTA: Performance evaluation of 192-slice dual-source CT

    To assess radiation dose and image quality in body CT-angiography (CTA) with automated attenuation-based tube voltage selection (ATVS) on a 192-slice dual-source CT (DSCT). Forty patients (69.5 ± 9.6 years) who had undergone body CTA with ATVS (ref.kVp 100, ref.mAs 90) using a 2x192-slice CT in single-source mode were retrospectively included. All patients had undergone prior CTA with a 2x128-slice CT and ATVS with identical imaging and contrast media protocols, serving for comparison. Images were reconstructed with iterative reconstruction at similar strength levels. Radiation dose was determined. Image quality was assessed semi-quantitatively (1:excellent, 5:non-diagnostic), aortic attenuation, noise and CNR were determined. As compared to 128-slice DSCT, 192-slice DSCT selected tube voltages were lower in 30 patients (75 %), higher in 3 (7.5 %), and similar in 7 patients (17.5 %). CTDIvol was lower with 192-slice DSCT (4.7 ± 1.9 mGy vs. 5.8 ± 2.1 mGy; p < 0.001). Subjective image quality, mean aortic attenuation (342 ± 67HU vs. 268 ± 67HU) and CNR (9.8 ± 2.5 vs. 8.2 ± 2.9) were higher with 192-slice DSCT (all p < 0.01), all datasets being diagnostic. Our study suggests that ATVS of 192-slice DSCT for body CTA is associated with an improved image quality and further radiation dose reduction of 19 % compared to 128-slice DSCT. (orig.)

  18. Automated attenuation-based tube voltage selection for body CTA: Performance evaluation of 192-slice dual-source CT

    Winklehner, Anna; Gordic, Sonja; Lauk, Eliane; Frauenfelder, Thomas; Alkadhi, Hatem; Husarik, Daniela B. [University Hospital Zurich, Institute for Diagnostic and Interventional Radiology, Zurich (Switzerland); Leschka, Sebastian [University Hospital Zurich, Institute for Diagnostic and Interventional Radiology, Zurich (Switzerland); Division of Radiology and Nuclear Medicine, St. Gallen (Switzerland)

    2015-08-15

    To assess radiation dose and image quality in body CT-angiography (CTA) with automated attenuation-based tube voltage selection (ATVS) on a 192-slice dual-source CT (DSCT). Forty patients (69.5 ± 9.6 years) who had undergone body CTA with ATVS (ref.kVp 100, ref.mAs 90) using a 2x192-slice CT in single-source mode were retrospectively included. All patients had undergone prior CTA with a 2x128-slice CT and ATVS with identical imaging and contrast media protocols, serving for comparison. Images were reconstructed with iterative reconstruction at similar strength levels. Radiation dose was determined. Image quality was assessed semi-quantitatively (1:excellent, 5:non-diagnostic), aortic attenuation, noise and CNR were determined. As compared to 128-slice DSCT, 192-slice DSCT selected tube voltages were lower in 30 patients (75 %), higher in 3 (7.5 %), and similar in 7 patients (17.5 %). CTDI{sub vol} was lower with 192-slice DSCT (4.7 ± 1.9 mGy vs. 5.8 ± 2.1 mGy; p < 0.001). Subjective image quality, mean aortic attenuation (342 ± 67HU vs. 268 ± 67HU) and CNR (9.8 ± 2.5 vs. 8.2 ± 2.9) were higher with 192-slice DSCT (all p < 0.01), all datasets being diagnostic. Our study suggests that ATVS of 192-slice DSCT for body CTA is associated with an improved image quality and further radiation dose reduction of 19 % compared to 128-slice DSCT. (orig.)

  19. Modeling of a residential house coupled with a dual source heat pump using TRNSYS software

    Highlights: • We simulate a residential house (type 56a on TRNSYS) coupled with heat pump system (type 20 on TRNSYS). • We examine the control function in the level of heat pump. • We study the temporal evolution of the temperature and the energy for 24 h operation in January and 4500 h operation in winter. • The system gives good results in all operating states. • The use of renewable energy and control function in the residential building is interesting. - Abstract: With the information technology revolution and the improving requirement for indoor air environment, energy consumption for air conditioning is increasing in Tunisia. In this research, a heating a residential house using the abundant and universal sources is proposed for a residential house in Tunisia. The effect of the incidence solar radiation in the coupling of a residential house and a heat pump system in all directions during the winter has been studied. The effect of ON–OFF technology in the level of the evaporator of the heat pump has been demonstrated. We present a mathematical description of the house on TRNSYS, as well as the numerical results of the simulation of coupling of the several components. The incidence solar radiation, the temperature distribution and the energy consumed and delivered, and its impact on air-conditioning load in rooms have been measured using the Tunisian climate. Numerical results have been obtained for 24 h in January and 4500 h operation in winter. Results show that the system may be satisfactorily used for residential building or greenhouse heating in the Mediterranean and region of Tunisia

  20. Effect of adenosine and adenosine analogs on [14C]aminopyrine accumulation by rabbit parietal cells

    Adenosine receptors that modulate adenylate cyclase activity have been identified recently in a number of tissues. Adenosine A2 receptor is stimulatory to adenylate cyclase, whereas adenosine A1 receptor is inhibitory to adenylate cyclase. We investigated the effect of adenosine and its analogs on [14C]aminopyrine accumulation by rabbit parietal cells. Rabbit gastric mucosal cells were isolated by enzyme digestion. Parietal cells were enriched by nonlinear percoll gradients. [14C]Aminopyrine accumulation was used as an indicator of acid secretion. The effect of 2-chloroadenosine on histamine-stimulated [14C]aminopyrine accumulation was studied. The effects of N-ethylcarboxamideadenosine, 2-chloroadenosine, stable analogs of adenosine, and adenosine on [14C]aminopyrine accumulation were assessed. Cyclic AMP content of parietal cells was determined by radioimmunoassay. Histamine and carbachol, known secretagogues, stimulated [14C]aminopyrine accumulation. 2-Chloroadenosine did not suppress histamine-stimulated [14C]aminopyrine accumulation. 2-Chloroadenosine, N-ethylcarboxamideadenosine, and adenosine dose dependently increased [14C]aminopyrine accumulation. The order of potency was N-ethylcarboxamideadenosine greater than 2-chloroadenosine greater than adenosine. 8-Phenyltheophylline and theophylline, adenosine-receptor antagonists, or cimetidine did not have significant effects on the increase of AP uptake induced by 2-chloroadenosine. Coadministration of dipyridamole, and adenosine uptake inhibitor, augmented the effect of adenosine on [14C]aminopyrine accumulation. 2-Chloroadenosine, N-ethylcarboxamideadenosine, and adenosine each induced a significant increase in cellular cyclic AMP. We conclude that there may be adenosine A2 receptors on rabbit parietal cells which modulate gastric acid secretion

  1. Optical Aptasensors for Adenosine Triphosphate

    Ng, Stella; Lim, Hui Si; Ma, Qian; Gao, Zhiqiang

    2016-01-01

    Nucleic acids are among the most researched and applied biomolecules. Their diverse two- and three-dimensional structures in conjunction with their robust chemistry and ease of manipulation provide a rare opportunity for sensor applications. Moreover, their high biocompatibility has seen them being used in the construction of in vivo assays. Various nucleic acid-based devices have been extensively studied as either the principal element in discrete molecule-like sensors or as the main component in the fabrication of sensing devices. The use of aptamers in sensors - aptasensors, in particular, has led to improvements in sensitivity, selectivity, and multiplexing capacity for a wide verity of analytes like proteins, nucleic acids, as well as small biomolecules such as glucose and adenosine triphosphate (ATP). This article reviews the progress in the use of aptamers as the principal component in sensors for optical detection of ATP with an emphasis on sensing mechanism, performance, and applications with some discussion on challenges and perspectives. PMID:27446501

  2. Clinical performance of dual-source computerized tomography (DSCT) in primary diagnostics of coronary heart diseases; Klinische Wertigkeit der Dual-Source-Computertomographie (DSCT) in der Primaerdiagnostik der koronaren Herzkrankheit

    Brunner, H.; Froehner, S.; Wagner, M.; Schmitt, R. [Herz- und Gefaessklinik GmbH, Bad Neustadt (Germany). Inst. fuer Diagnostische und Interventionelle Radiologie; Brunn, J.; Gietzen, F.H.; Kerber, S. [Herz- und Gefaessklinik GmbH, Bad Neustadt (Germany). Fachbereich Kardiologie

    2008-07-01

    Dual-source-CT-technology (DSCT) improves temporal resolution of cardiac computed tomography to 83 ms per heart-phase. In this study, the clinical performance of this new method is evaluated. Materials and Methods: In fifty patients (33 male, 17 female; age 50{+-}13 years) with suspected coronary heart disease, CT angiography (slice thickness 0,75 mm, contrast-agent 60-80 ml iomeprol) was performed with a Somatom Definition scanner. Based on the coronary 15-segment-model of the AHA, scores for image quality and lumen reduction were established to enable the observer, to give recommendations for further therapy. Results: Out of 750 possible AHA-segments, 655 were depicted (87,3%). 591 segments (90,2%) were assessed without any limitation of quality, 49 (7,5%) segments showed moderate, and 15 (2,3%) segments severe limitation in image quality. 508 (77,6%) segments were without pathological findings, 92 (14,0%) segments had minimal atherosclerotic lesions, 42 (6,4%) segments suffered from stenoses with lumen reduction less than 70%, and 13 (2,0%) showed significant stenoses of more than 70%. In 31 patients (62%), coronary heart disease was ruled out by CT angiography without any need for further non-invasive or invasive diagnostics. 8 patients (16%) underwent stress-testing for ischemia. In 11 (22%) patients coronary angiography was recommended, and DSCT findings were confirmed in 10 cases. Only one LCx stenosis was overestimated in DSCT. Conclusion: Contrast-enhanced DSCT is a powerful tool in diagnosis of coronary heart disease. 98% of coronary segments could be assessed in diagnostic quality, and at least 90% of haemodynamically significant coronary stenoses were detected. (orig.)

  3. Dual-source computed tomography. Effect on regional and global left ventricular function assessment compared to magnetic resonance imaging; Untersuchung der regionalen und globalen linksventrikulaeren Funktion mit der Dual-Source-Computertomografie im Vergleich zur Magnetresonanztomografie

    Lueders, F.; Seifarth, H.; Wessling, J.; Heindel, W.; Juergens, Kai Uwe [Inst. fuer Klinische Radiologie, Universitaetsklinikum Muenster (Germany); Fischbach, R. [Klinik fuer Radiologie, Nuklearmedizin und Neuroradiologie, Asklepios Klinik Altona (Germany)

    2009-10-15

    Purpose: to determine regional and global left ventricular (LV) functional parameters and to perform segmental wall thickness (SWT) and motion (WM) analysis of dual source CT (DSCT) with optimized temporal resolution versus MRI. Materials and Methods: 30 patients with known or suspected CAD, non-obstructive HCM, DCM, ARVCM, Fallot Tetralogy, cardiac sarcoidosis and cardiac metastasis underwent DSCT and MRI. The DSCT and MR images were evaluated: end-systolic (ESV), end-diastolic LV (EDV) volumes, stroke volume (SV), ejection fraction (EF), and myocardial mass (MM) as well as LV wall thickening and segmental WM applying the AHA model were obtained and statistically analyzed. Results: The mean LV-EDV (r = 0.96) and ESV (r = 0.98) as well as LV-EF (r = 0.97), SV (r = 0.83), and MM (r = 0.95) correlated well. Bland Altman analysis revealed little systematic underestimation of LV-EF (-1.1 {+-} 7.8%), EDV (-0.3 {+-} 18.2 ml), SV (-1.3 {+-} 16.7 ml) and little overestimation of ESV (1.1 {+-} 7.8 ml) and MM (12.8 {+-} 14.4 g) determined by DSCT. Systolic reconstruction time points correlated well (DSCT 32.2 {+-} 6.7 vs. MRI 35.6 {+-} 4.4% RR-interval). The LV wall thickness obtained by DSCT and MRI showed close correlation in all segments (diameter diff 0.42 {+-} 1 mm). In 413 segments (89%) WM abnormalities were equally rated, whereas DSCT tended to underestimate the degree of wall motion impairment. Conclusion: DSCT with optimized temporal resolution enables regional and global LV function analysis as well as segmental WM analysis in good correlation with MRI. However, the degree of WM impairment is slightly underestimated by DSCT. (orig.)

  4. Adenosine regulation of alveolar fluid clearance

    Factor, Phillip; Mutlu, Göskhan M.; Chen, Lan; Mohameed, Jameel; Akhmedov, Alexander T.; Meng, Fan Jing; Jilling, Tamas; Lewis, Erin Rachel; Johnson, Meshell D.; Xu, Anna; Kass, Daniel; Martino, Janice M.; Bellmeyer, Amy; Albazi, John S.; Emala, Charles

    2007-01-01

    Adenosine is a purine nucleoside that regulates cell function through G protein-coupled receptors that activate or inhibit adenylyl cyclase. Based on the understanding that cAMP regulates alveolar epithelial active Na+ transport, we hypothesized that adenosine and its receptors have the potential to regulate alveolar ion transport and airspace fluid content. Herein, we report that type 1 (A1R), 2a (A2aR), 2b (A2bR), and 3 (A3R) adenosine receptors are present in rat and mouse lungs and alveol...

  5. Development of vacuum ultraviolet absorption spectroscopy system for wide measurement range of number density using a dual-tube inductively coupled plasma light source

    A vacuum ultraviolet absorption spectroscopy system for a wide measurement range of atomic number densities is developed. Dual-tube inductively coupled plasma was used as a light source. The probe beam profile was optimized for the target number density range by changing the mass flow rate of the inner and outer tubes. This system was verified using cold xenon gas. As a result, the measurement number density range was extended from the conventional two orders to five orders of magnitude.

  6. Development of vacuum ultraviolet absorption spectroscopy system for wide measurement range of number density using a dual-tube inductively coupled plasma light source

    Kuwahara, Akira; Matsui, Makoto; Yamagiwa, Yoshiki

    2012-12-01

    A vacuum ultraviolet absorption spectroscopy system for a wide measurement range of atomic number densities is developed. Dual-tube inductively coupled plasma was used as a light source. The probe beam profile was optimized for the target number density range by changing the mass flow rate of the inner and outer tubes. This system was verified using cold xenon gas. As a result, the measurement number density range was extended from the conventional two orders to five orders of magnitude.

  7. A dual-inexact fuzzy stochastic model for water resources management and non-point source pollution mitigation under multiple uncertainties

    Dong, C.; Q. Tan; Huang, G.-H.; Cai, Y.-P.

    2014-01-01

    In this research, a dual-inexact fuzzy stochastic programming (DIFSP) method was developed for supporting the planning of water and farmland use management system considering the non-point source pollution mitigation under uncertainty. The random boundary interval (RBI) was incorporated into DIFSP through integrating fuzzy linear programming (FLP) and chance-constrained programming (CCP) approaches within an interval linear programming (ILP) framework. This developed method ...

  8. Carotid and cerebrovascular disease in symptomatic patients with type 2 diabetes: assessment of prevalence and plaque morphology by dual-source computed tomography angiography

    Deng Wen; Shao Heng; Dong Zhi-hui; Chu Zhi-gang; Yang Zhi-gang; He Ci; Chen Jing; Peng Li-qing; Tang Si-shi; Xiao Jia-he

    2010-01-01

    Abstract Background Plaque morphology directly correlates with risk of embolism and the recently developed dual-source computed tomography angiography (DSCTA) may help to detect plaques more precisely. The aim of our study was to evaluate the prevalence and morphology of carotid and cerebrovascular atherosclerotic plaques in patients with symptomatic type 2 diabetes mellitus (DM) by DSCTA. Methods From July 2009 to August 2010, DSCTA was prospectively performed in 125 consecutive patients wit...

  9. A fast neutron and dual-energy gamma-ray absorption method (NEUDEG) for investigating materials using a 252Cf source

    DEXA (dual-energy X-ray absorption) is widely used in airport scanners, industrial scanners and bone densitometers. DEXA determines the properties of materials by measuring the absorption differences of X-rays from a bremsstrahlung tube source with and without filtering. Filtering creates a beam with a higher mean energy, which causes lower material absorption. The absorption difference between measurements (those with a filter subtracted from those without a filter) is a positive number that increases with the effective atomic number of the material. In this paper, the concept of using a filter to create a dual beam and an absorption difference in materials is applied to radiation from a 252Cf source, called NEUDEG (neutron and dual-energy gamma absorption). NEUDEG includes absorptions for fast neutrons as well as the dual photon beams and thus an incentive for developing the method is that, unlike DEXA, it is inherently sensitive to the hydrogen content of materials. In this paper, a model for the absorption difference and absorption sum in NEUDEG is presented using the combined gamma ray and fast neutron mass attenuation coefficients. Absorption differences can be either positive or negative in NEUDEG, increasing with increases in the effective atomic number and decreasing with increases in the hydrogen content. Sample sets of absorption difference curves are calculated for materials with typical gamma-ray and fast neutron mass attenuation coefficients. The model, which uses tabulated mass attenuated coefficients, agrees with experimental data for porcelain tiles and polyethylene sheets. The effects of “beam hardening” are also investigated. - Highlights: • Creation of a dual neutron/gamma beam from 252Cf is described. • An absorption model is developed using mass attenuation coefficients. • A graphical method is used to show sample results from the model. • The model is successfully compared with experimental results. • The importance of

  10. Evaluation of high-pitch dual-source CT angiography for evaluation of coronary and carotid-cerebrovascular arteries

    Sun, Kai [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Li, Kuncheng, E-mail: cjr.likuncheng@vip.163.com [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Han, Ruijuan [Department of Cardiology, Chaoyang Hospital, Capital Medical University, Beijing 100020 (China); Li, Wenhuan; Chen, Nan; Yang, Qi; Du, Xiangying; Wang, Chen [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Liu, Guorong; Li, Yuechun [Department of Neurology Baotou Central Hospital, Inner Mongolia, Baotou 014040 (China); Zhou, Maorong [Department of Radiology, Baotou Central Hospital, Inner Mongolia, Baotou 014040 (China); Li, Ligang; Heidrun, Endt [CT BM Clinic Marketing, Siemens Healthcare, Beijing 100102 (China)

    2015-03-15

    Objectives: To explore the feasibility and diagnostic accuracy of a combined one-step high-pitch dual-source computed tomography angiography (CTA) technique for evaluation of coronary and carotid-cerebrovascular arteries. Materials and methods: 85 symptomatic patients suspected of coronary artery and cerebrovascular disease referred for simultaneous coronary and carotid-cerebrovascular CTA were included. Additional invasive angiography of the coronary and cerebral arteries was performed within 30 days in 23 and 13 patients, respectively. The objective parameters of image quality, the mean CT attenuations, image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were evaluated. The subjective image quality of vessels was also assessed by 2 independent radiologists blinded to the patients’ medical history and scan protocols. The diagnostic performance of CTA including sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for the detection or exclusion of significant artery stenosis was calculated using the chi-squared test of contingency and correlated with the results of invasive angiography representing the standard of reference. Results: Image quality was rated excellent (score 1) in 95.3% (1074/1127), good (score 2) in 3.3% (37/1127), adequate (score 3) in 1.0% (11/1127), and non-diagnostic (score 4) in 0.4% (5/1127) of coronary segments. Image quality of carotid and cerebral vessels was rated mostly excellent (score 1, 95.12% [78/82]; score 2, 3.66% [3/82]; score 3, 1.22% [1/82]). The sensitivity, specificity, PPV and NPV for the detection of coronary stenosis were 92.2% (81.1–97.7%), 95.2% (91.7–97.5%), 79.6% (67.1–89.1%) and 98.3% (95.8–99.5%), respectively. For the detection of carotid and cerebral artery stenosis, CTA demonstrated a sensitivity of 92.8% (80.5–98.4%), a specificity of 93.5% (88.3–96.8%), a PPV of 79.6% (65.6–89.7%) and a NPV of 97.9% (94.1–99.5%). The effective

  11. Coronary calcium screening with dual-source CT: reliability of ungated, high-pitch chest CT in comparison with dedicated calcium-scoring CT

    Hutt, Antoine; Faivre, Jean-Baptiste; Remy, Jacques; Remy-Jardin, Martine [CHRU et Universite de Lille, Department of Thoracic Imaging, Hospital Calmette (EA 2694), Lille (France); Duhamel, Alain; Deken, Valerie [CHRU et Universite de Lille, Department of Biostatistics (EA 2694), Lille (France); Molinari, Francesco [Centre Hospitalier General de Tourcoing, Department of Radiology, Tourcoing (France)

    2016-06-15

    To investigate the reliability of ungated, high-pitch dual-source CT for coronary artery calcium (CAC) screening. One hundred and eighty-five smokers underwent a dual-source CT examination with acquisition of two sets of images during the same session: (a) ungated, high-pitch and high-temporal resolution acquisition over the entire thorax (i.e., chest CT); (b) prospectively ECG-triggered acquisition over the cardiac cavities (i.e., cardiac CT). Sensitivity and specificity of chest CT for detecting positive CAC scores were 96.4 % and 100 %, respectively. There was excellent inter-technique agreement for determining the quantitative CAC score (ICC = 0.986). The mean difference between the two techniques was 11.27, representing 1.81 % of the average of the two techniques. The inter-technique agreement for categorizing patients into the four ranks of severity was excellent (weighted kappa = 0.95; 95 % CI 0.93-0.98). The inter-technique differences for quantitative CAC scores did not correlate with BMI (r = 0.05, p = 0.575) or heart rate (r = -0.06, p = 0.95); 87.2 % of them were explained by differences at the level of the right coronary artery (RCA: 0.8718; LAD: 0.1008; LCx: 0.0139; LM: 0.0136). Ungated, high-pitch dual-source CT is a reliable imaging mode for CAC screening in the conditions of routine chest CT examinations. (orig.)

  12. Influence of energy density of different light sources on knoop hardness of a dual-cured resin cement

    Evandro Piva

    2008-06-01

    Full Text Available The purpose of this study was to evaluate the Knoop hardness of a dual-cured resin-based luting cement irradiated with different light sources as well energy density through a ceramic sample. Three light-curing unit (LCUs were tested: tungsten halogen light (HAL, light-emitting diode (LED and xenon plasma-arc (PAC lamp. Disc-shaped specimens were fabricated from a resin-based cement (Enforce. Three energy doses were used by modifying the irradiance (I of each LCU and the irradiation time (T: 24 Jcm-2 (I/2x2T, 24 Jcm-2 (IxT and 48 Jcm-2 (Ix2T. Energy doses were applied through a 2.0-mm-thick ceramic sample (Duceram Plus. Three groups underwent direct irradiation over the resin cement with the different LCUs and a chemically-activated group served as a control. Thirteen groups were tested (n=10. Knoop hardness number (KHN means were obtained from cross-sectional areas. Two-way ANOVA and the Holm-Sidak method were used for statistical comparisons of activation mode and energy doses (a=5%. Application of 48 J.cm-2 energy dose through the ceramic using LED (50.5±2.8 and HAL (50.9±3.7 produced significantly higher KHN means (p<0.05 than the control (44.7±3.8. LED showed statistically similar performance to HAL. Only HAL showed a relationship between the increase of LCU energy dose and hardness increase.

  13. Intensive lipid-lowering therapy with rosuvastatin stabilizes lipid-rich coronary plaques. Evaluation using dual-source computed tomography

    Clinical studies using invasive modalities have reported that statin therapy stabilizes coronary plaque vulnerability. The serial changes of lipid-rich coronary plaques (LRCPs) during rosuvastatin treatment were evaluated non-invasively in patients with acute coronary syndrome (ACS) using dual-source computed tomography (DSCT). A total of 11 consecutive ACS patients, and 13 LRCPs were serially evaluated on DSCT before and 24 weeks after rosuvastatin treatment. Compared with the baseline, there was no change in post-treatment minimal lumen diameter, lumen volume, or longitudinal length of LRCPs. By contrast, the ratio of lipid core volume to plaque volume significantly decreased from 48.0±9.9% to 43.7±10.6% (P=0.04), and plaque volume decreased from 144.5±85.5 mm3 to 119.8±78.0 mm3 (P=0.07). The remodeling index of target LRCPs significantly decreased from 1.16±0.10 to 1.06±0.12 (P=0.02). Percent reduction of plaque volume was significantly greater in patients with a lower ratio of low-density lipoprotein to high-density lipoprotein (L/H ratio ≤1.5) at follow-up than patients with higher L/H ratio (>1.5; median -31.7% vs. -6.8%, P=0.03). Rosuvastatin therapy reduced the volume of lipid cores and LRCPs and increased the CT attenuation value of LRCPs. DSCT is an effective modality for the non-invasive evaluation of LRCPs in patients with ACS. (author)

  14. Multi-slice and dual-source CT in cardiac imaging. Principles - protocols - indications - outlook. 2. ed.

    Ohnesorge, B.M. [Siemens Medical Solutions Group China, Beijing (China); Flohr, T.G. [Siemens Medical Solutions, Forchheim (Germany). Div. CT Physics and Applications Development; Becker, C.R.; Reiser, M.F. [Muenchen Univ. Klinikum Grosshadern (Germany). Dept. of Clinical Radiology; Knez, A [Muenchen Univ. Klinikum Grosshadern (Germany). Section Head Imaging

    2007-07-01

    Cardiac diseases, and in particular coronary artery disease, are the leading cause of death and morbidity in industrialized countries. The development of non-invasive imaging techniques for the heart and the coronary arteries has been considered a key element in improving patient care. A breakthrough in cardiac imaging using CT occurred in 1998, with the introduction of multi-slice computed tomography (CT). Since then, amazing advances in performance have taken place with scanners that acquire up to 64 slices per rotation. This book discusses the state-of-the-art developments in multi-slice CT for cardiac imaging as well as those that can be anticipated in the future. It serves as a comprehensive work that covers all aspects of this technology, from the technical fundamentals and image evaluation all the way to clinical indications and protocol recommendations. This fully reworked second edition draws on the most recent clinical experience obtained with 16- and 64-slice CT scanners by world-leading experts from Europe and the United States. It also includes 'hands-on' experience in the form of 10 representative clinical case studies, which are included on the accompanying CD. As a further highlight, the latest results of the very recently introduced dual-source CT, which may soon represent the CT technology of choice for cardiac applications, are presented. This book will not only convince the reader that multi-slice cardiac CT has arrived in clinical practice, it will also make a significant contribution to the education of radiologists, cardiologists, technologists, and physicists-whether newcomers, experienced users, or researchers. (orig.)

  15. Systolic prospectively ECG-triggered dual-source CT angiography for evaluation of the coronary arteries in heart transplant recipients

    To assess feasibility, image quality, and radiation dose of prospectively ECG-triggered coronary CT angiography (CTA) in orthotopic heart transplant (OHT) recipients. 47 consecutive OHT recipients (40 men, mean age 62.1±10.9 years, mean heart rate 86.3±14.4 bpm) underwent dual-source CTA to rule out coronary allograft vasculopathy in a prospectively ECG-triggered mode with data acquisition during 35% to 45% of the cardiac cycle. Two independent observers blindly assessed image quality on a per-segment and per-vessel basis using a four-point scale (1-excellent, 4-not evaluable). Scores 1-3 were considered acceptable for diagnosis. Multivariate analysis was performed to evaluate differences between image quality scores obtained at different reconstruction intervals. Effective radiation doses were calculated. 671 coronary segments were evaluated. Interobserver agreement on the image quality was κ=0.75. Diagnostic image quality was observed in 93.9%, 95.5% and 93.3% of the segments at 35%, 40% and 45% reconstruction intervals. Mean image quality score was 1.5±0.7 for the entire coronary tree, 1.4±0.7 for the RCA, 1.6±0.8 for the LCA and 1.6±0.7 for the Cx at the best reconstruction interval. Estimated mean radiation dose was 4.5±1.2 mSv. Systolic prospectively ECG-triggered CTA allows diagnostic image quality coronary angiograms in OHT recipients at low radiation doses. (orig.)

  16. Effect of age and plaque morphology on diagnostic accuracy of dual source multidetector computed tomography coronary angiography

    Hamza Sunman; Giray Kabak; Lale Tokgzolu; Ali Oto; Kudret Aytemir; Hikmet Yorgun; Uur Canpolat; Ali Taher; Edis Demiri; Tuncay Hazrolan; Leventahiner; Ergn B.Kaya

    2014-01-01

    Background Multidetector computed tomography (MDCT) coronary angiography represents one of the most exciting technological revolutions in cardiac imaging and it has been increasingly used in the diagnosis of coronary artery disease. The purpose of this study is to investigate the effect of age and coronary plaque calcification on diagnostic accuracy of MDCT. Methods The patients were examined by using dual-source MDCT and conventional coronary angiography. MDCT results were analyzed with regard to the severity (>50%stenosis) and morphology (non-calcified, mixed, or calcified) of coronary atherosclerotic plaques evaluated in a 16-segment model. Results In total, 181 patients (94 men and 87 women) with 2,687 coronary artery segments were examined with MDCT. Ninety three patients were older than 65 years of age (group A, 42 men) and 88 were younger (group B, 52 men). Two-hundred nine coronary artery segments (7.2%) were ex-cluded because of small distal coronary vessel segments and/or motion artifacts. The overall number of segments with non-diagnostic image quality was similar in both groups of patients. Of the 2,687 evaluated segments, 157 (5.8%) were significantly diseased, and 144 of them were correctly detected by MDCT. Diagnostic evaluation showed that the sensitivity, positive predictive value, specificity, and negative pre-dictive value were 89.5%, 62.5%, 96.0%, and 99.2%, respectively in group A, and 95.2%, 64.8%, 97.5%, and 99.8%in group B, respectively. In addition, detailed segment-based analyses in coronary segments with non-calcified, mixed and calcified plaques in both groups were simi-lar diagnostic accuracy. Conclusions Very high diagnostic accuracy observed in this study suggests that MDCT coronary angiography could be a suitable diagnostic tool for not only younger patients but also for older patients.

  17. An individualized contrast material injection protocol with respect to patient-related factors for dual-source CT coronary angiography

    Aim: To optimize contrast media (CM) injection protocols by individually tailoring the dose to the patient's body weight (BW), body mass index (BMI) and heart rate (HR) at dual-source computed tomography coronary angiography (DSCT-CA). Materials and methods: A total of 423 patients were prospectively enrolled and were randomly assigned to four groups. The control group received 80 ml CM at 5 ml/s. For the HR-optimized group, the injection duration was the same as the scan duration plus 8 s. In the Body-optimized group, the dose of CM was tailored to BW and BMI. In the HR + Body-optimized group, CM protocols tailored to body size and scan duration were applied. Individual variability of arterial attenuation and incidence of arterial over-opacification (attenuation >500 HU) in the four groups were compared. Correlations between BW, BMI, HR, and arterial attenuations were evaluated in the four groups, respectively. Results: Reduced individual variability of arterial attenuation and a significantly lower incidence of arterial over-opacification were found in the Body-optimized group and HR + Body-optimized group. Arterial attenuation was inversely correlated with BW, BMI, and HR in the control group, inversely correlated with BW and BMI in the HR-optimized group, and inversely correlated with HR in the Body-optimized group. In the HR + Body-optimized group, arterial attenuation was not significantly correlated with BW, BMI, or HR respectively. Conclusion: CM protocols individually tailored to BW, BMI, and HR can lead to reduced individual variability and a lower incidence of over-opacification of arterial attenuation, but also can reduce the influence of BW, BMI, and HR on arterial attenuations at DSCT-CA

  18. Diagnostic accuracy of dual-source CT coronary angiography with prospective electrocardiography-triggering in patients with higher heart rate

    Objective: To evaluate the diagnostic accuracy of dual-source CT (DSCT) prospective ECG-triggering coronary angiography in patients with different heart rate (HR). Methods: One hundred and three patients with suspected coronary artery disease underwent DSCT prospective ECG-triggered coronary angiography and invasive coronary angiography (ICA). The patients were grouped by HR during CT scans: low HR ( 70 bpm, n= 33). Image quality was scored using a 4-point scale. The sensitivity and specificity of DSCT in detecting ? 50% stenosis were compared among subgroups where ICA was the gold standard. The differences were compared by using the χ2 test of contingency on a per-segment and per-vessel basis. Results: Image quality of 1580 coronary artery segments m 1648 (95.9%) met the requirements for diagnosis. The image quality scores were (3.1±0.3), (3.1±0.3) and (3.0±0.4) point for subgroups (χ2=2.80, P>0.05). Sensitivity and specificity were 82.8% (77/93) and 98.4% (428/435), 88.3% (91/103) and 98.7% (442/448), and 80.3% (57/71) and 98.6% (424/430) for different subgroups (χ2 were 0.69 and 0.13, all P>0.05). The overall area under the receiver operating characteristic (ROC) curve was 0.94 (95% CI=0.92-0.96). The average effective radiation dose was (3.60±1.60) mSv. Conclusion: DSCT coronary angiography with prospective ECG-triggering could be used for patients with high HR. And the diagnostic accuracy was not statistical significant between the patients with low HR and patients with medium to high HR. (authors)

  19. Imaging of pulmonary vein anatomy using low-dose prospective ECG-triggered dual-source computed tomography

    Blanke, Philipp; Baumann, Tobias; Langer, Mathias; Pache, Gregor [University Hospital Freiburg, Department of Diagnostic Radiology, Freiburg (Germany)

    2010-08-15

    To prospectively investigate the feasibility, image quality and radiation dose estimates for computed tomography angiography (CTA) of the pulmonary veins and left atrium using prospective electrocardiography (ECG)-triggered sequential dual-source (DS) data acquisition at end-systole in patients with paroxysmal atrial fibrillation undergoing radiofrequency ablation. Thirty-five patients (mean age 66.2 {+-} 12.6 years) with paroxysmal atrial fibrillation underwent prospective ECG-triggered sequential DS-CTA with tube current (250 mAs/rotation) centred 250 ms past the R-peak. Tube voltage was adjusted to the BMI (<25 kg/m{sup 2}: 100 kV, >25 kg/m{sup 2}: 120 kV). Presence of motion or stair-step artefacts was assessed. Effective radiation dose was calculated from the dose-length product. All data sets could be integrated into the electroanatomical mapping system. Twenty-two patients (63%) were in sinus rhythm (mean heart rate 69.2 {+-} 11.1 bpm, variability 1.0 {+-} 1.7 bpm) and 13 (37%) showed an ECG pattern of atrial fibrillation (mean heart rate 84.8 {+-} 16.6 bpm, variability 17.9 {+-} 7.5 bpm). Minor step artefacts were observed in three patients (23%) with atrial fibrillation. Mean estimated effective dose was 1.1 {+-} 0.3 and 3.0 {+-} 0.5 mSv for 100 and 120 kV respectively. Imaging of pulmonary vein anatomy is feasible using prospective ECG-triggered sequential data acquisition at end-systole regardless of heart rate or rhythm at the benefit of low radiation dose. (orig.)

  20. Characterization of coronary atherosclerosis by dual-source computed tomography and HU-based color mapping: a pilot study

    To assess HU-based color mapping for characterization of coronary plaque, using intravascular ultrasound virtual histology (IVUS-VH) as a standard of reference. Dual-source computed tomography and IVUS-VH were prospectively performed in 13 patients. In five lesions, HU thresholds of the color-coding software were calibrated to IVUS-VH. In a 15-lesion verification cohort, volumes of vessel, lumen and plaque or percentages of lipid, fibrous and calcified components were obtained through use of pre-set HU cut-offs as well as through purely visual adjustment of color maps. Calibrated HU ranges for fatty or fibrous plaque, lumen and calcification were -10-69, 70-158, 159-436 and 437+. Using these cut-offs, HU-based analysis achieved good agreement of plaque volume with IVUS (47.0 vs. 51.0 mm3). Visual segmentation led to significant overestimation of atheroma (61.6 vs. 51.0 mm3; P = 0.04) Correlation coefficients for volumes of vessel, lumen and plaque were 0.92, 0.87 and 0.83 with HU-based analysis or 0.92, 0.85 and 0.71 with visual evaluation. With both methods, correlation of percentage plaque composition was poor or insignificant. HU-based plaque analysis showed good reproducibility with intra-class correlation coefficients being 0.90 for plaque volume and 0.81, 0.94 or 0.98 for percentages of fatty, fibrous or calcified components. With use of optimized HU thresholds, color mapping allows for accurate and reproducible quantification of coronary plaque. (orig.)

  1. Adenosine triphosphate inhibition of yeast trehalase.

    Panek, A D

    1969-09-01

    Yeast trehalase has been found to be inhibited non-competitively by adenosine triphosphate. Such a biological control could explain the accumulation of trehalose during the stationary phase of the growth curve. PMID:5370287

  2. Role of adenosine receptors in caffeine tolerance

    Caffeine is a competitive antagonist at adenosine receptors. Receptor up-regulation during chronic drug treatment has been proposed to be the mechanism of tolerance to the behavioral stimulant effects of caffeine. This study reassessed the role of adenosine receptors in caffeine tolerance. Separate groups of rats were given scheduled access to drinking bottles containing plain tap water or a 0.1% solution of caffeine. Daily drug intake averaged 60-75 mg/kg and resulted in complete tolerance to caffeine-induced stimulation of locomotor activity, which could not be surmounted by increasing the dose of caffeine. 5'-N-ethylcarboxamidoadenosine (0.001-1.0 mg/kg) dose dependently decreased the locomotor activity of caffeine-tolerant rats and their water-treated controls but was 8-fold more potent in the latter group. Caffeine (1.0-10 mg/kg) injected concurrently with 5-N-ethylcarboxamidoadenosine antagonized the decreases in locomotor activity comparably in both groups. Apparent pA2 values for tolerant and control rats also were comparable: 5.05 and 5.11. Thus, the adenosine-antagonist activity of caffeine was undiminished in tolerant rats. The effects of chronic caffeine administration on parameters of adenosine receptor binding and function were measured in cerebral cortex. There were no differences between brain tissue from control and caffeine-treated rats in number and affinity of adenosine binding sites or in receptor-mediated increases (A2 adenosine receptor) and decreases (A1 adenosine receptor) in cAMP accumulation. These results are consistent with theoretical arguments that changes in receptor density should not affect the potency of a competitive antagonist. Experimental evidence and theoretical considerations indicate that up-regulation of adenosine receptors is not the mechanism of tolerance to caffeine-induced stimulation of locomotor activity

  3. Electrocardiographic profile of adenosine pharmacological stress testing

    Sun, Hao; TIAN, YUEQIN; ZHENG, LIHUI; Pan, Qingrong; XIE, BOQIA

    2015-01-01

    Adenosine stress testing in conjunction with radionuclide myocardial perfusion imaging has become a common approach for the detection of coronary artery diseases in patients who are unable to perform adequate levels of exercise. However, specific electrocardiographic alterations during the test have been rarely described. Using a Chinese population, the aim of the present study was to provide a detailed electrocardiographic profile of adenosine stress testing. The study population included 1,...

  4. Application of dual-source-computed tomography in pediatric cardiology in children within the first year of life; Einsatz der Dual-Source-Computertomografie in der Kinderkardiologie bei Kindern im ersten Lebensjahr

    Hausmann, P.; Stenger, A.; Dittrich, S.; Gloeckler, M. [Erlangen-Nuernberg Univ., Erlangen (Germany). Pediatric Cardiology; Cesnjevar, R.; Rueffer, A. [Erlangen-Nuernberg Univ., Erlangen (Germany). Congenital Heart Surgery; Hammon, M.; Uder, M.; Rompel, O. [Erlangen-Nuernberg Univ., Erlangen (Germany). Radiology

    2016-02-15

    To assess fields of application and value of dual source computed tomography (DSCT) for diagnostics and therapy in patients with congenital heart disease during their first year of life. Evaluation of image quality, surgical use and radiation exposure of 2nd and 3rd generation DSCT. DSCT was applied in 118 cases between January 2012 and October 2014 for diagnostics of congenital heart defects. 2nd generation was used in 91 cases until April 2014 and 3rd generation in 27 cases during the period thereafter. 3D reconstructions of the image data were created for clinical diagnostics and planning of interventions. Image quality was assessed using a 4-point-scale. The visibility of the mammary arteries was analyzed, and signal-to-noise-ratio (SNR) and contrast-to-noise-ratio (CNR) were calculated. The usefulness of 3D-reconstructions for surgical planning was rated using a 5-point-scale. Radiation exposure and contrast dye consumption were determined. All cases were analyzed retrospectively. DSCT was successfully used in 118 cases. All image data obtained were interpretable. More than 60 percent of cases did not show any artifacts. The mammary arteries were visible down to the diaphragmatic arch in more than 80 percent of cases. Diagnostic value and surgical benefit were evaluated as ''useful'' or as ''essential'' in all cases. Median radiation dose was 0.4 mSv and 0.27 mSv for the 2nd and 3rd generation DSCT, respectively. Consumption of contrast dye was 2 ml/kg in all cases. DSCT is a modern and extremely helpful technique for diagnostics and planning of interventions in patients with complex congenital heart defects. Extracardiac vascular structures in particular can be depicted three-dimensionally at high resolution. The use of iterative reconstruction with 3rd generation DSCT yielded image quality similar to that of 2nd generation DSCT at considerably reduced radiation exposure level compared to 2nd generation DSCT. 3rd

  5. The use of dual source CT in diagnosis of carotid body tumors%双源CT在颈动脉体瘤诊治中的应用

    曹罡; 郭婷; 周长圣; 张森林; 孟昭业; 杨震; 董震; 徐金科; 毛钊

    2011-01-01

    Objective To evaluate the value of dual source CT in diagnosis and treatment of carotid body tumors.Methods Between Sep, 2007 and April 2010, a total of 5 patients who were planed to be diagnosed as carotid body underwent dual source CT.The relationship of the tumour and the near vessels, and the character of the tumor were identified by analysis of clinical signs and imaging results.The risk factors and feasibility of operations were evaluated before done.The tumors were resected.Results The clear edge mass of soft tissue was shown in all 5 patients in dual source CT images at the bifurcation of the common carotid artery.The minors presented obviously enhanced high-density after contrast media administration.The tumors have plenty blood supply.4 patients with small tumor in only one side show especially “cup-sign”.One female patient with bilateral tumors didn't have“ cup-sign” and significant narrow blood vessel, however the tumors were much bigger.5 patients were all diagnosed by dual source CT.The tumonrs were resected and reserved common carotid artery and internal carotid artery.Couclusion Dual source CT is convenience, non-trauma.Its information can be composited.It can offer overall image information of the blood vessel disease such as CBT, which is very important for diagnosis, typing, evaluation the risk of the operation of CBT.So, dual source CT can be the first choice in the diagnosis of carotid body tumor.%目的 评价双源CT(dual source CT,DSCT)在颈动脉体瘤(carotid body tumor,CBT)诊断、治疗中的价值.方法 2007年9月至2010年4月对临床拟诊CBT的5例行颈部双源CT检查,根据临床体征及影像学检查确定肿瘤的性质及其与颈总、颈内、颈外动脉的关系,评估手术的风险及可行性.结果 5例DSCT检查结果均显示颈总动脉分叉处界线清晰的软组织实性肿块.增强扫描后病灶均呈明显强化,瘤体血供丰富.4例单侧瘤体较小CBT呈现典型的"高脚杯"征.1例双

  6. Dual energy virtual non-contrast technique of dual-source head CT angiography in diagnosis of meningiomas%双源CT双能量颅脑CTA虚拟平扫诊断脑膜瘤

    谢晓洁; 邓亚敏; 曾宪春; 康绍磊; 韩丹

    2012-01-01

    Objective To investigate the clinical value of the dual energy virtual non-contrast technique of dual-source head CT angiography (CTA) in preoperative examination of meningioma. Methods CT images of 49 patients with pathologically confirmed meningiomas were retrospectively analyzed. Conventional non-contrast (CNC) and dual energy CTA scan were performed, and virtual non-contrast (VNC) and iodine-enhanced images were obtained with postprocessed technology. The mean CT value, signal-to-noise ratio (SNR), image quality, lesions detectability and radiation dose were compared between VNC and CNC images. The supply artery of tumor and relationship between tumor and adjacent intracranial vessel were observed on head CTA image from head bone removal using dual energy technique. Results CT value, SNR, and image quality scores of CNC were higher than those of VNC (all P<0. 05). The image quality scores of VNC were all above 3, which could meet the diagnostic requirements. There was no statistical difference in the size, shape, intratumoral calcification, necrosis and peritumoral edema of lesions between CNC and VNC images. The ability of VNC to display calcification inside meningioma was somehow limited compared with CNC. The radiation dose of dual energy CTA was 1. 71 mSv (61. 07%) , lower than that of CNC and conventional enhancement scan. Conclusion Dual-source CT dual energy technique can obtain VNC, iodine-enhanced and CTA images by single enhanced scan, and is excellent in preoperative examination for meningioma.%目的 探讨双源CT(DSCT)双能量颅脑CTA虚拟平扫在脑膜瘤术前检查中的临床价值.方法 回顾性分析经手术病理证实的49例脑膜瘤患者的CT图像,包括常规平扫(CNC)及双能量增强图像,经处理得到虚拟平扫(VNC)图和碘图;对比两组平扫病灶平均CT值、SNR、图像质量评分、病灶形态及辐射剂量.应用双能去骨获得颅脑CTA图像,观察肿瘤与周围血管的关

  7. 双源CT双能量虚拟平扫在结直肠病变的应用%Preliminary Application of Dual-energy Dual-source CT Virtual Non-contrast Imaging in Colorectal Lesions

    王勇; 雷静; 韩丹; 赵卫; 杨石平; 熊倩

    2014-01-01

    Purpose To assess the feasibility of applying dual-energy dual-source CT virtual non-contrast (VNC) imaging in the diagnosis of colorectal diseases. Materials and Methods Eighty-ifve patients with clinically suspected colorectal lesions underwent abdominal CT scan as well as arterial and venous phase dual-energy enhanced scan, VCN images of arterial and venous phase were obtained using the dual-energy software, the differences of image quality, radiation dose and diagnostic coincidence rate between the true non-contrast scan and VNC images were compared. Results The radiation dose of two-phase dual-energy scan was 34.8%lower when compared with the conventional three-phase scans. The CT values of the intestinal lesions, metastasis lymph nodes and intestinal fat in VNC were lower than the true unenhanced scan (P0.05), and neither was the diagnostic coincidence rate for intestinal diseases (P>0.05). The noise level of images obtained from VNC was lower than that of the real non-contrast scan (P0.05). Conclusion For colorectal lesions, the virtual non-contrast images from the dual-energy dual-source CT scan can be used to reduce the radiation dose without effecting image quality and diagnosis accuracy.%目的:探讨双源CT双能量虚拟平扫(VNC)技术在结直肠病变诊断中应用的可行性。资料与方法对85例临床疑诊结直肠病变患者行腹部CT平扫及动、静脉期双能量增强扫描,经双能软件处理得到动、静脉期VNC图,比较真实平扫与VNC在图像质量、辐射剂量及诊断符合率方面的差异。结果双能双期扫描辐射剂量较常规三期扫描辐射剂量降低约34.8%。VNC CT值在肠道病变、转移淋巴结、肠周脂肪中低于真实平扫(P0.05)。真实平扫及动、静脉期VNC观察到的肠壁厚度、淋巴结大小、周围侵犯及肝转移差异无统计学意义(P>0.05),对肠道疾病的诊断符合率差异无统计学意义(P>0.05)。VNC

  8. Structure Parameter Optimization of Air-water Dual-source Compound Heat-exchanger%空气-水双热源复合换热器结构参数优化

    张超; 董家昀; 赵晓丹; 周光辉

    2012-01-01

    空气-水双热源复合换热器是太阳能-空气双热源复合热泵系统的核心部件,空气-水双热源复台换热器的结构参数对空气-水双热源复合换热器的换热性能以及太阳能-空气双热源复合热泵的系统性能具有重要影响.建立了太阳能-空气双热源复合热泵系统的数学模型,利用数学模拟的方法研究了空气-水双热源复合换热器结构参数对热泵系统能效比的影响,并确定了模拟工况下换热器结构参数的优化方案.%The air-water dual-source compound heat-exchanger is the key component of the solar-air dual-source compound heat pump system. The heat-exchanging performance of the air-water dual-source compound heat-exchanger and the system performance of the solar-air dual-source compound heat pump system are largely depended on the structure parameter of the air-water dual-source compound heat-exchanger. The mathematic model of the solar-air dual-source compound heat pump system has been established. The mathematic simulation method has been used to study the effect of the structure parameters of air-water dual-source compound heat-exchanger on the energy-efficiency ratio of the solar-air dual-source compound heat pump system, and the optimization scheme of the structure parameters under the simulating condition have been determined.

  9. Plasma characteristics of single- and dual-electrode ion source systems utilized in low-energy ion extraction

    Vasquez, M. R., E-mail: mrvasquez@upd.edu.ph [Department of Mining, Metallurgical, and Materials Engineering, College of Engineering, University of the Philippines, Diliman, Quezon City 1101 (Philippines); Tokumura, S.; Kasuya, T.; Wada, M. [Graduate School of Science and Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan)

    2014-02-15

    Discharge characteristics in the upstream as well as in the downstream regions of a 50-eV positive ion beam were measured along the beam axis. Single- and dual-electrode configurations made of 0.1-mm diameter tungsten wires were tested. By varying the upstream discharge parameters, the shape of the sheath edge around the extractors, which can either be “planar” or “cylindrical,” can be controlled. The sheath eventually affected the simultaneous extraction of ions and neutralizing electrons. The dual-electrode configuration at the lower discharge current, revealed a homogeneous discharge downstream. At this condition, the edge of the sheath can be inferred to be “planar” which allowed the uniform extraction and propagation of low-energy ions at longer distances. The dual-electrode configuration was capable of transmitting low-energy ions up to 70 mm downstream.

  10. 双源CT双能量肝脏虚拟平扫的临床应用%Clinical application of virtual non-contrast scans to liver with dual-source CT in dual-energy mode

    乐剑平; 刘东华; 梅尧; 文祥明; 赵君

    2014-01-01

    目的:研究双源CT双能量虚拟平扫技术在肝脏扫描中的应用价值。方法:对37例上腹部扫描患者行上腹部普通平扫及动脉期、门脉期双能量扫描。通过Liver VNC软件处理后,可以获得动脉期、门脉期虚拟平扫数据,并与普通平扫对比,比较其在平均CT值、信噪比( SNR)、病灶检出率、图像质量及辐射剂量上的差异。结果:虚拟平扫和普通平扫在病灶检出率上无明显差异(P>0.05)。虚拟平扫肝脏CT值高于普通平扫(P<0.05);虚拟平扫图像SNR高于普通平扫(P<0.05)。两组虚拟平扫之间差异无统计学意义(P>0.05)。虚拟平扫的图像质量均可满足临床诊断需求。应用虚拟平扫,可取消普通平扫,辐射剂量可降低34%。结论:双源CT的虚拟平扫技术在保证图像质量的前提下降低了辐射剂量,可取代普通平扫,具有临床应用的潜力。%Objective:To evaluate the diagnostic value of applying virtual non-contrast scanning to liver lesions with dual-source,dual-energy computed tomography( CT) .Methods:Conventional non-enhanced abdominal CT scanning was performed in 37 patients,followed by scans during the hepatic arterial phase and portal phase with dual-source in dual-energy mode.The images were generated with the built-in liver VNC program for the raw data during the hepatic arterial phase and portal phase in virtual non-contrasted manner,and the previous data were compared with those obtained by conventional non-en-hanced scans regarding the differences of mean CT value,signal-to-noise ratio(SNR),focal lesions detected,imaging quality and radiation dose.Results:Although the focal lesions detected remained relatively comparable by either virtual or conventional non-contrasted scanning(P>0.05),yet the CT Hu values for liver were higher on virtual non-contrast CT images than the conventional counterparts(P0.05),and generated sim-ilar diagnostic

  11. The impact of heart rate on image quality and reconstruction timing of dual-source CT coronary angiography

    Objective: To evaluate the impact of patient's heart rate (HR) on coronary CT angiography (CTA) image quality (IQ) and reconstruction timing in dual-source CT (DSCT). Methods Ninety-five patients with suspicion of coronary artery disease were examined with a DSCT scanner (Somatom Definition, Siemens) using 32 x 0.6 mm collimation. All patients were divided three groups according to the heart rate (HR): group 1, HR ≤ 70 beats per minute (bpm), n=26; group 2, HR >70 bpm to ≤90 bpm, n=37; group 3, HR > 90 bpm, n=32. No beta-blockers were taken before CT scan. 50- 60 ml of nonionic contrast agent were injected with a rate of 5 ml/s. Images were reconstructed from 10% to 100% of the R-R interval using single-segment reconstruction. Two readers independently assessed IQ of all coronary, segments using a 3-point scale from excellent (1) to non-assessable (3) for coronary segments and the relationship between IQ and the HR. Results: Overall mean IQ score was 1.31 ± 0.55 for all patients with 1.08 ± 0.27 for group 1, 1.32 ± 0.58 for group 2 and 1.47 ± 0.61 for group 3. The IQ was better in the LAD than the RCA and LCX (P<0.01). Only 1.4% (19/1386) of coronary artery segments were considered non-assessable due to the motion artifacts. Optimal image quality of all coronary segments in 74 patients (77.9%) can be achieved with one reconstruction data set. The best IQ was predominately in diastole (88.5%) in group 1, while the best IQ was in systole (84.4%) in group 3. Conclusions: DSCT can achieve the optimal IQ with a wide range of HR using single-segment reconstruction. With the increasing of HR, the timing of data reconstruction for the best IQ shifts from mid-diastole to systole. (authors)

  12. Quantitative assessment of left ventricular function with dual-source CT in comparison to cardiac magnetic resonance imaging: initial findings

    Cardiac magnetic resonance imaging and echocardiography are currently regarded as standard modalities for the quantification of left ventricular volumes and ejection fraction. With the recent introduction of dual-source computedtomography (DSCT), the increased temporal resolution of 83 ms should also improve the assessment of cardiac function in CT. The aim of this study was to evaluate the accuracy of DSCT in the assessment of left ventricular functional parameters with cardiac magnetic resonance imaging (MRI) as standard of reference. Fifteen patients (two female, 13 male; mean age 50.8 ± 19.2 years) underwent CT and MRI examinations on a DSCT (Somatom Definition; Siemens Medical Solutions, Forchheim, Germany) and a 3.0-Tesla MR scanner (Magnetom Trio; Siemens Medical Solutions), respectively. Multiphase axial CT images were analysed with a semiautomatic region growing algorithms (Syngo Circulation; Siemens Medical Solutions) by two independent blinded observers. In MRI, dynamic cine loops of short axis slices were evaluated with semiautomatic contour detection software (ARGUS; Siemens Medical Solutions) independently by two readers. End-systolic volume (ESV), end-diastolic volume (EDV), ejection fraction (EF) and stroke volume (SV) were determined for both modalities, and correlation coefficient, systematic error, limits of agreement and inter-observer variability were assessed. In DSCT, EDV and ESV were 135.8 ± 41.9 ml and 54.9 ± 29.6 ml, respectively, compared with 132.1 ± 40.8 ml EDV and 57.6 ± 27.3 ml ESV in MRI. Thus, EDV was overestimated by 3.7 ml (limits of agreement -46.1/+53.6), while ESV was underestimated by 2.6 ml (-36.6/+31.4). Mean EF was 61.6 ± 12.4% in DSCT and 57.9 ± 9.0% in MRI, resulting in an overestimation of EF by 3.8% with limits of agreement at -14.7 and +22.2%. Rank correlation rho values were 0.81 for EDV (P = 0.0024), 0.79 for ESV (P 0.0031) and 0.64 for EF (P = 0.0168). The kappa value of inter-observer variability were

  13. Evaluation of radiation dose in chest scan with enhanced dual-source computed tomography in children with congenital heart disease

    Objective: To evaluate the radiation dose from enhanced dual-source computed Tomography (DSCT) scan on children with congenital heart disease (CHD). Methods: Seventy children with CHD, age from 1 month to 8 years old, were scanned with enhanced DSCT. Children were divided by age into 5 years old group. The differences among three groups were tested by F test. Then, the SNK test was used to compare the difference between each group. Multiple linear regression analysis was used to test the relationship of dose length product (DLP) with the age, weight, voltage, current, pitch and scan sheet. Results: The average value of DLP was (144.46± 74.07) mGy·cm for all the 70 cases, and that of effective does (ED) was (4.68±2.34) mSv. There were significant differences of DLP among the 3 groups [ 5 years (208.00±73.87) mGy · cm, F=8.26, P=0.0009]. The SNK test showed statistical differences of DLP between 5 years old group (q=5.21, 6.52, P=0.009, 0.004). The difference of DLP between 1-5 years old group and > 5 years old group did not reach significant (q=0.28, P=0.48). The differences of ED was not statistically significant among the three groups [ 5 years (3.74±1.33) mSv, F=0.54, P=0.59]. DLP was positively correlated with age (4.3 years, r=0.54186, P=0.0008), weight (12.1 kg, r=0.56371, P=0.0004), voltage [(95.48±6.99) kV, r=0.63269, P<0.01], current [(138.55±40.67) mA, r=0.79608, P< 0.0001] and scan sheet (236.10±46.51, r=0.72192, P<0.01). DLP was negative correlated with pitch (0.48±0.03, r=-0.46693, P=0.0047). Conclusion: Higher DLP was observed in children over 1 year old under enhanced DSCT scan, but ED was not statistically significant among the three groups due to the higher K value in the children under 1 year old. (authors)

  14. Application of dual-source-computed tomography in pediatric cardiology in children within the first year of life

    To assess fields of application and value of dual source computed tomography (DSCT) for diagnostics and therapy in patients with congenital heart disease during their first year of life. Evaluation of image quality, surgical use and radiation exposure of 2nd and 3rd generation DSCT. DSCT was applied in 118 cases between January 2012 and October 2014 for diagnostics of congenital heart defects. 2nd generation was used in 91 cases until April 2014 and 3rd generation in 27 cases during the period thereafter. 3D reconstructions of the image data were created for clinical diagnostics and planning of interventions. Image quality was assessed using a 4-point-scale. The visibility of the mammary arteries was analyzed, and signal-to-noise-ratio (SNR) and contrast-to-noise-ratio (CNR) were calculated. The usefulness of 3D-reconstructions for surgical planning was rated using a 5-point-scale. Radiation exposure and contrast dye consumption were determined. All cases were analyzed retrospectively. DSCT was successfully used in 118 cases. All image data obtained were interpretable. More than 60 percent of cases did not show any artifacts. The mammary arteries were visible down to the diaphragmatic arch in more than 80 percent of cases. Diagnostic value and surgical benefit were evaluated as ''useful'' or as ''essential'' in all cases. Median radiation dose was 0.4 mSv and 0.27 mSv for the 2nd and 3rd generation DSCT, respectively. Consumption of contrast dye was 2 ml/kg in all cases. DSCT is a modern and extremely helpful technique for diagnostics and planning of interventions in patients with complex congenital heart defects. Extracardiac vascular structures in particular can be depicted three-dimensionally at high resolution. The use of iterative reconstruction with 3rd generation DSCT yielded image quality similar to that of 2nd generation DSCT at considerably reduced radiation exposure level compared to 2nd generation DSCT. 3rd

  15. Assessment of regional left ventricular function by Dual Source Computed Tomography: Interobserver variability and validation to laevocardiography

    Pflederer, T. [Department of Internal Medicine 2 (Cardiology), University of Erlangen (Germany)], E-mail: tobiaspflederer@web.de; Ho, K.T. [Department of Cardiology, Tan Tock Seng Hospital (Singapore)], E-mail: contact@ttsh.com.sg; Anger, T. [Department of Internal Medicine 2 (Cardiology), University of Erlangen (Germany)], E-mail: thomas.anger@uk-erlangen.de; Kraehner, R. [Department of Internal Medicine 2 (Cardiology), University of Erlangen (Germany)], E-mail: robert.kraehner@uk-erlangen.de; Ropers, D. [Department of Internal Medicine 2 (Cardiology), University of Erlangen (Germany)], E-mail: dieter.ropers@uk-erlangen.de; Muschiol, G. [Department of Internal Medicine 2 (Cardiology), University of Erlangen (Germany)], E-mail: gerd.muschiol@uk-erlangen.de; Renz, A. [Department of Internal Medicine 2 (Cardiology), University of Erlangen (Germany)], E-mail: alexandra.renz@uk-erlangen.de; Daniel, W.G. [Department of Internal Medicine 2 (Cardiology), University of Erlangen (Germany)], E-mail: werner.daniel@uk-erlangen.de; Achenbach, S. [Department of Internal Medicine 2 (Cardiology), University of Erlangen (Germany)], E-mail: stephan.achenbach@uk-erlangen.de

    2009-10-15

    Objective: Assessment of left ventricular function is possible in contrast-enhanced cardiac CT data sets. However, rapid ventricular motion especially in systole can lead to artifacts. Dual Source Computed Tomography (DSCT) has high temporal resolution which effectively limits motion artifact. We therefore assessed the accuracy of DSCT to detect regional left ventricular wall motion abnormalities in comparison to invasive cine angiocardiography. Methods: We analyzed DSCT data sets of 50 patients (39 male, 11 female, mean age: 61 {+-} 10 years) which were acquired after intravenous injection of 55-70 mL contrast agent (rotation time: 330 ms, collimation: 2 mm x 64 mm x 0.6 mm, 120 kV, 380 mAs, ECG-correlated tube current modulation). 10 data sets consisting of transaxial slices with a slice thickness of 1.5 mm, an increment of 1.0 mm and a matrix of 256 x 256 pixels were reconstructed at 10 time instants during the cardiac cycle (0-90% in 10% increments). The data sets were analyzed visually by two independent readers, using standard left ventricular planes, concerning regional wall motion abnormalities. DSCT was verified in a blinded fashion against cine ventriculography performed during cardiac catheterization (RAO and LAO projection), using a 7-segment model. Analysis was performed on a per-patient (presence of at least one hypo-, a- or dyskinetic segment) and on a per-segment basis. Results: Concerning the presence of a wall motion abnormality, the two observers agreed in 340/350 segments (97%) and 48/50 patients (96%). In invasive cine angiocardiography, 22 of 50 patients displayed at least one segment with abnormal contraction. To detect these patients, DSCT showed a sensitivity of 95% (21/22), specificity of 96% (27/28), positive predictive value of 95% and negative predictive value of 96%. Out of a total of 350 left ventricular segments, 66 segments had abnormal contraction in cine angiocardiography (34 hypokinetic, 26 akinetic, 6 dyskinetic). For detection

  16. Adenosine stress protocols for myocardial perfusion imaging

    Baškot Branislav

    2008-01-01

    Full Text Available Background/Aim. Treadmill test combined with myocardial perfusion scintigraphy (MPS is a commonly used technique in the assessment of coronary artery disease. There are many patients, however, who may not be able to undergo treadmill test. Such patients would benefit from pharmacological stress procedures combined with MPS. The most commonly used pharmacological agents for cardiac stress are coronary vasodilatators (adenosine, dipyridamol and catecholamines. Concomitant low-level treadmill exercise with adenosine pharmacologic stress (AdenoEX during MPS has become commonly used in recent years. A number of studies have demonstrated a beneficial impact of AdenoEX protocol. The aim of the study was, besides introducing into practice the two types of protocols of pharmatological stress test with adenosine, as a preparation for MPS, to compare and monitor the frequency of their side effects to quality, acquisition, as well as to standardize the onset time of acquisition (diagnostic imaging for both protocols. Methods. A total of 130 patients underwent pharmacological stress test with adenosine (vasodilatator. In 108 of the patients we performed concomitant exercise (AdenoEX of low level (50W by a bicycle ergometar. In 28 of the patients we performed Adenosine abbreviated protocol (AdenoSCAN. Side effects of adenosine were followed and compared between the two kinds of protocols AdenoEX and AdenoSCAN. Also compared were image quality and suggested time of acquisition after the stress test. Results. Numerous side effects were found, but being short-lived they did not require any active interventions. The benefit of AdenoEX versus AdenoSCAN included decreased side effects (62% vs 87%, improved safety and patients tolerance, improved target-to-background ratios because of less subdiaphragmatic activity, earlier acquisition, and improved sensitivity. Conclusion. The safety and efficacy of adenosine pharmacological stress is even better with concomitant

  17. Dual-source spiral CT with pitch up to 3.2 and 75 ms temporal resolution: Image reconstruction and assessment of image quality

    Flohr, Thomas G.; Leng Shuai; Yu Lifeng; Allmendinger, Thomas; Bruder, Herbert; Petersilka, Martin; Eusemann, Christian D.; Stierstorfer, Karl; Schmidt, Bernhard; McCollough, Cynthia H. [Siemens Healthcare, Computed Tomography, 91301 Forchheim, Germany and Department of Diagnostic Radiology, Eberhard-Karls-Universitaet, 72076 Tuebingen (Germany); Department of Radiology, Mayo Clinic, Rochester, Minnesota 55905 (United States); Siemens Healthcare, Computed Tomography, 91301 Forchheim (Germany); Department of Radiology, Mayo Clinic, Rochester, Minnesota 55905 (United States)

    2009-12-15

    Purpose: To present the theory for image reconstruction of a high-pitch, high-temporal-resolution spiral scan mode for dual-source CT (DSCT) and evaluate its image quality and dose. Methods: With the use of two x-ray sources and two data acquisition systems, spiral CT exams having a nominal temporal resolution per image of up to one-quarter of the gantry rotation time can be acquired using pitch values up to 3.2. The scan field of view (SFOV) for this mode, however, is limited to the SFOV of the second detector as a maximum, depending on the pitch. Spatial and low contrast resolution, image uniformity and noise, CT number accuracy and linearity, and radiation dose were assessed using the ACR CT accreditation phantom, a 30 cm diameter cylindrical water phantom or a 32 cm diameter cylindrical PMMA CTDI phantom. Slice sensitivity profiles (SSPs) were measured for different nominal slice thicknesses, and an anthropomorphic phantom was used to assess image artifacts. Results were compared between single-source scans at pitch=1.0 and dual-source scans at pitch=3.2. In addition, image quality and temporal resolution of an ECG-triggered version of the DSCT high-pitch spiral scan mode were evaluated with a moving coronary artery phantom, and radiation dose was assessed in comparison with other existing cardiac scan techniques. Results: No significant differences in quantitative measures of image quality were found between single-source scans at pitch=1.0 and dual-source scans at pitch=3.2 for spatial and low contrast resolution, CT number accuracy and linearity, SSPs, image uniformity, and noise. The pitch value (1.6{<=}pitch{<=}3.2) had only a minor impact on radiation dose and image noise when the effective tube current time product (mA s/pitch) was kept constant. However, while not severe, artifacts were found to be more prevalent for the dual-source pitch=3.2 scan mode when structures varied markedly along the z axis, particularly for head scans. Images of the moving

  18. Third-generation dual-source 70-kVp chest CT angiography with advanced iterative reconstruction in young children: image quality and radiation dose reduction

    Rompel, Oliver; Janka, Rolf; Lell, Michael M.; Uder, Michael; Hammon, Matthias [University Hospital Erlangen, Department of Radiology, Erlangen (Germany); Gloeckler, Martin; Dittrich, Sven [University Hospital Erlangen, Department of Pediatric Cardiology, Erlangen (Germany); Cesnjevar, Robert [University Hospital Erlangen, Department of Pediatric Cardiac Surgery, Erlangen (Germany)

    2016-04-15

    Many technical updates have been made in multi-detector CT. To evaluate image quality and radiation dose of high-pitch second- and third-generation dual-source chest CT angiography and to assess the effects of different levels of advanced modeled iterative reconstruction (ADMIRE) in newborns and children. Chest CT angiography (70 kVp) was performed in 42 children (age 158 ± 267 days, range 1-1,194 days). We evaluated subjective and objective image quality, and radiation dose with filtered back projection (FBP) and different strength levels of ADMIRE. For comparison were 42 matched controls examined with a second-generation 128-slice dual-source CT-scanner (80 kVp). ADMIRE demonstrated improved objective and subjective image quality (P <.01). Mean signal/noise, contrast/noise and subjective image quality were 11.9, 10.0 and 1.9, respectively, for the 80 kVp mode and 11.2, 10.0 and 1.9 for the 70 kVp mode. With ADMIRE, the corresponding values for the 70 kVp mode were 13.7, 12.1 and 1.4 at strength level 2 and 17.6, 15.6 and 1.2 at strength level 4. Mean CTDI{sub vol}, DLP and effective dose were significantly lower with the 70-kVp mode (0.31 mGy, 5.33 mGy*cm, 0.36 mSv) compared to the 80-kVp mode (0.46 mGy, 9.17 mGy*cm, 0.62 mSv; P <.01). The third-generation dual-source CT at 70 kVp provided good objective and subjective image quality at lower radiation exposure. ADMIRE improved objective and subjective image quality. (orig.)

  19. The study of diagnostic accuracy of prospectively electrocardiogram-triggered high-pitch spiral acquisition using Flash dual-sources CT for the assessment of coronary stenoses

    Objectives: To prospectively investigate the diagnostic accuracy,image quality and radiation doses of prospectively ECG-triggered high-pitch spiral acquisition computed tomography coronary angiography (CTCA) using Flash dual-source CT for the diagnosis of significant coronary stenoses. Methods: Seventy-three patients underwent both CTCA and CCA. CTCA was performed using a Flash dual-source CT system with data acquisition at a high-pitch of 3.4. CCA served as the standard of reference. Radiation dose values were calculated using the dose-length product. Results: There were 925 vessel segments in 73 patients. (1) Diagnostic accuracy: the sensitivity, specificity and positive and negative predictive values were 93.2% (164/176), 96.4% (722/749), 85.9% (164/191), 98.4% (722/734) for segment assessment and 98.4% (123/125), 87.4% (83/95), 91.1% (123/135), 97.6% (83/85) for vessel assessment and 100% (44/44), 89.7% (26/29), 93.6% (44/47), 100% (26/26) for patient assessment. (2) Image quality: there were 2 coronary segments of right coronary artery and one segment of left circumflex artery with non-diagnostic image quality. There was no non-diagnostic image quality in left anterior descending artery. (3) Radiation dose: the effective radiation dose was (1.14 ± 0.10) mSv. Conclusions: CTCA using the prospectively ECG-triggered high-pitch spiral mode of the Flash dual-source CT system is associated with high diagnostic accuracy for the assessment of coronary artery stenoses at low dose. (authors)

  20. Third-generation dual-source 70-kVp chest CT angiography with advanced iterative reconstruction in young children: image quality and radiation dose reduction

    Many technical updates have been made in multi-detector CT. To evaluate image quality and radiation dose of high-pitch second- and third-generation dual-source chest CT angiography and to assess the effects of different levels of advanced modeled iterative reconstruction (ADMIRE) in newborns and children. Chest CT angiography (70 kVp) was performed in 42 children (age 158 ± 267 days, range 1-1,194 days). We evaluated subjective and objective image quality, and radiation dose with filtered back projection (FBP) and different strength levels of ADMIRE. For comparison were 42 matched controls examined with a second-generation 128-slice dual-source CT-scanner (80 kVp). ADMIRE demonstrated improved objective and subjective image quality (P <.01). Mean signal/noise, contrast/noise and subjective image quality were 11.9, 10.0 and 1.9, respectively, for the 80 kVp mode and 11.2, 10.0 and 1.9 for the 70 kVp mode. With ADMIRE, the corresponding values for the 70 kVp mode were 13.7, 12.1 and 1.4 at strength level 2 and 17.6, 15.6 and 1.2 at strength level 4. Mean CTDIvol, DLP and effective dose were significantly lower with the 70-kVp mode (0.31 mGy, 5.33 mGy*cm, 0.36 mSv) compared to the 80-kVp mode (0.46 mGy, 9.17 mGy*cm, 0.62 mSv; P <.01). The third-generation dual-source CT at 70 kVp provided good objective and subjective image quality at lower radiation exposure. ADMIRE improved objective and subjective image quality. (orig.)

  1. Radio-chromatographic determination of plasmatic adenosine deaminase (A.D.); Determination radiochromatographique de l'adenosine deaminase (A.D.)

    Chivot, J.J.; Depernet, D.; Caen, J. [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes

    1970-07-01

    We were able, by using a radio-chromatographic method, to measure an adenosine deaminase activity in normal human heparinized platelet-poor plasma, which can degrade 0.016 {mu}M adenosine. This activity suppressed by heating 56 C for 30 minutes is inhibited by high concentrations of urea and is proportional to the amount of plasma, source of enzyme, in the systems. (authors) [French] Nous avons pu, en utilisant une methode radiochromatographique, mesurer une activite adenosine deaminasique dans le plasma humain pauvre en plaquettes heparine qui peut degrader 0,016 {mu}M d'adenosine. Cette activite qui est supprimee par chauffage a 56 degres pendant 30 minutes, est reduite par conservation a -20 C pendant une semaine, est inhibee par d'importantes concentrations d'uree et ne l'est pas, ni par le dipyridamol, ni par le pHMB. Cette activite est proportionnelle a la quantite de plasma, source d'enzyme, mise dans les differents systemes reactifs. (auteur)

  2. Screening for coronary artery disease in respiratory patients: comparison of single- and dual-source CT in patients with a heart rate above 70 bpm

    Pansini, Vittorio; Remy-Jardin, Martine; Tacelli, Nunzia; Faivre, Jean-Baptiste; Remy, Jacques [University Center of Lille, Department of Thoracic Imaging, Hospital Calmette, Lille cedex (France); Flohr, Thomas [Siemens Medical Solutions, Department of Research and Development, Forchheim (Germany); Deken, Valerie; Duhamel, Alain [University Center of Lille, Department of Medical Statistics, Lille (France)

    2008-10-15

    To evaluate the assessibility of coronary arteries in respiratory patients with high heart rates. This study was based on the comparative analysis of two paired populations of 54 patients with a heart rate >70 bpm evaluated with dual-source (group 1) and single-source (group 2) CT. The mean heart rate was 89.1 bpm in group 1 and 86.7 bpm in group 2 (P=0.26). The mean number of assessable segments per patient was significantly higher in group 1 compared to group 2 (P{<=}0.0001). The proportions of patients in whom proximal and mid-coronary segments were assessable (i.e., the anatomical level enabling screening for asymptomatic coronary artery disease) were 35.3% for heart rates <110 bpm, 35.6% for heart rates <100 bpm, 40% for heart rates <90 bpm, and 60% for heart rates <80 bpm in group 1 and 11.3, 12.2, 8.8, and 10% for the corresponding thresholds in group 2 (P<0.05). In both groups of patients, coronary artery imaging was obtained from standard CT angiograms of the chest. The improvement in coronary imaging with dual-source CT suggests that high heart rates should no longer be considered as contraindications for ECG-gated CT angiograms of the chest whenever clinically relevant. (orig.)

  3. Myocardial Bridging of the Left Anterior Descending Coronary Artery: Depiction Rate and Morphologic Features by Dual-Source CT Coronary Angiography

    Hwang, Jin Ho; Ko, Sung Min; Roh, Hong Gee; Song, Meong Gun; Shin, Je Kyoun; Chee, Hyun Kun; Kim, Joon Suk

    2010-01-01

    Objective To evaluate the depiction rate and morphologic features of myocardial bridging (MB) of the left anterior descending coronary artery (LAD) using dual-source CT (DSCT). Materials and Methods CT scans from a total of 1,353 patients who underwent DSCT were reviewed retrospectively for LAD-MB. Seventy-eight patients were excluded due to poor image quality or poor enhancement of the coronary artery. The length and depth of the MB were analyzed and classified as superficial or deep with re...

  4. A dual-plane co-RASOR technique for accurate and rapid tracking and position verification of an Ir-192 source for single fraction HDR brachytherapy

    de Leeuw, Hendrik; Moerland, Marinus A.; van Vulpen, Marco; Seevinck, Peter R.; Bakker, Chris J. G.

    2013-11-01

    Effective high-dose-rate (HDR) treatment requires accurate and independent treatment verification to ensure that the treatment proceeds as prescribed, in particular if a high dose is given, as in single fraction therapy. Contrary to CT imaging and fluoroscopy, MR imaging provides high soft tissue contrast. Conventional MR techniques, however, do not offer the temporal resolution in combination with the 3D spatial resolution required for accurate brachytherapy source localization. We have developed an MR imaging method (center-out RAdial Sampling with Off-Resonance (co-RASOR)) that generates high positive contrast in the geometrical center of field perturbing objects, such as HDR brachytherapy sources. co-RASOR generates high positive contrast in the geometric center of an Ir-192 source by applying a frequency offset to center-out encoded data. To obtain high spatial accuracy in 3D with adequate temporal resolution, two orthogonal center-out encoded 2D images are applied instead of a full 3D acquisition. Its accuracy in 3D is demonstrated by 3D MRI and CT. The 2D images show high positive contrast in the geometric center of non-radioactive Ir-192 sources, with signal intensities up to 160% of the average signal intensity in the surrounding medium. The accuracy with which the center of the Ir-192 source is located by the dual-plane MRI acquisition corresponds closely to the accuracy obtained by 3D MRI and CT imaging. The positive contrast is shown to be obtained in homogeneous and in heterogeneous tissue. The dual-plane MRI technique allows the brachytherapy source to be tracked in 3D with millimeter accuracy with a temporal resolution of approximately 4 s.

  5. Assessment of global left ventricular function with dual-source computed tomography in patients with valvular heart disease

    Background: Left ventricular (LV) function is a vital parameter for prognosis, therapy guidance, and follow-up of cardiovascular disease. Dual-source computed tomography (DSCT) provides an accurate analysis of global LV function. Purpose: To assess the performance of DSCT in the determination of global LV functional parameters in comparison with cardiovascular magnetic resonance (CMR) and two-dimensional transthoracic echocardiography (2D-TTE) in patients with valvular heart disease (VHD). Material and Methods: A total of 111 patients (58 men, mean age 49.9 years) with known VHD and who underwent DSCT, 2D-TTE, and CMR a period of 2 weeks before undergoing valve surgery were included in this study. LV end-systolic volume (ESV), end-diastolic volume (EDV), stroke volume (SV), and ejection fraction (EF) were calculated by DSCT using the threshold-based technique, by 2D-TTE using a modified Simpson's method, and by CMR using Simpson's method. Agreement for parameters of LV global function was determined with the Pearson's correlation coefficient (r) and Bland-Altman analysis. All the DSCT and CMR data-sets were assessed independently by two readers. Results: Fifty of the total 111 patients had aortic VHD, 29 patients had mitral VHD, and 32 patients had mixed aortic and mitral VHD. An excellent inter-observer agreement was seen for the assessment of global LV function using DSCT (r 0.910-0.983) and CMR (r = 0.854-0.965). An excellent or good correlation (r 0.93, 0.95, 0.87, and 0.71, respectively, P < 0.001) was noted between the DSCT and 2D-TTE values for EDV, ESV, SV, and EF. EDV (33.7 mL, P < 0.001), ESV (12.1 mL, P < 0.001), SV (21.2 mL, P < 0.001), and EF (1.6%, P = 0.019) were significantly overestimated by DSCT when compared with 2D-TTE. An excellent correlation (r = 0.96, 0.97, 0.91, and 0.94, respectively, P < 0.001) between DSCT and CMR was seen in the evaluation of EDV, ESV, SV, and EF. EDV (15.9 mL, P < 0.001), ESV (7.3 mL, P < 0.001), and SV (8.5 mL, P < 0

  6. Assessment of global left ventricular function with dual-source computed tomography in patients with valvular heart disease

    Bak, So Hyeon; Jeon, Hae Jeong (Dept. of Radiology, Konkuk Univ. Hospital, Konkuk Univ. School of Medicine, Seoul (Korea, Republic of)); Ko, Sung Min (Dept. of Radiology, Konkuk Univ. Hospital, Konkuk Univ. School of Medicine, Seoul (Korea, Republic of); Research Inst. of Medical Science, Konkuk Univ. Hospital, Konkuk Univ. School of Medicine, Seoul (Korea, Republic of)), Email: 20070437@kuh.ac.kr; Yang, Hyun Suk; Hwang, Hweung Kon (Dept. of Cardiology, Konkuk Univ. Hospital, Konkuk Univ. School of Medicine, Seoul (Korea, Republic of)); Song, Meong Gun (Dept. of Thoracic Surgery, Konkuk Univ. Hospital, Konkuk Univ. School of Medicine, Seoul (Korea, Republic of))

    2012-04-15

    Background: Left ventricular (LV) function is a vital parameter for prognosis, therapy guidance, and follow-up of cardiovascular disease. Dual-source computed tomography (DSCT) provides an accurate analysis of global LV function. Purpose: To assess the performance of DSCT in the determination of global LV functional parameters in comparison with cardiovascular magnetic resonance (CMR) and two-dimensional transthoracic echocardiography (2D-TTE) in patients with valvular heart disease (VHD). Material and Methods: A total of 111 patients (58 men, mean age 49.9 years) with known VHD and who underwent DSCT, 2D-TTE, and CMR a period of 2 weeks before undergoing valve surgery were included in this study. LV end-systolic volume (ESV), end-diastolic volume (EDV), stroke volume (SV), and ejection fraction (EF) were calculated by DSCT using the threshold-based technique, by 2D-TTE using a modified Simpson's method, and by CMR using Simpson's method. Agreement for parameters of LV global function was determined with the Pearson's correlation coefficient (r) and Bland-Altman analysis. All the DSCT and CMR data-sets were assessed independently by two readers. Results: Fifty of the total 111 patients had aortic VHD, 29 patients had mitral VHD, and 32 patients had mixed aortic and mitral VHD. An excellent inter-observer agreement was seen for the assessment of global LV function using DSCT (r 0.910-0.983) and CMR (r = 0.854-0.965). An excellent or good correlation (r 0.93, 0.95, 0.87, and 0.71, respectively, P < 0.001) was noted between the DSCT and 2D-TTE values for EDV, ESV, SV, and EF. EDV (33.7 mL, P < 0.001), ESV (12.1 mL, P < 0.001), SV (21.2 mL, P < 0.001), and EF (1.6%, P = 0.019) were significantly overestimated by DSCT when compared with 2D-TTE. An excellent correlation (r = 0.96, 0.97, 0.91, and 0.94, respectively, P < 0.001) between DSCT and CMR was seen in the evaluation of EDV, ESV, SV, and EF. EDV (15.9 mL, P < 0.001), ESV (7.3 mL, P < 0.001), and SV

  7. Imaging findings of coronary sinus with left atrium muscle connections on dual-source CT coronary angiography

    Objective: To investigate the morphologic features of coronary sinus (CS)-left atrium muscle connections,and evaluate the function and anatomical features of coronary sinus on dual-source CT coronary angiography (DSCTCA). Methods: Images of DSCTCA of 144 patients [control group consisted of 96 patients, and atrial fibrillation (AF) group consisted of 48 patients] were reviewed. The existence of coronary sinus-right atrium muscle connections was indirectly evaluated by measuring the cross-sectional area changes of the CS during atrial systole and atrial diastolic. The number, location, length of the CS-left atrium muscle connections and the relationship between CS-left atrium muscle connections and CS morphological characteristics were studied. The t test for continuous variables and Chi-square test for categorical variables were used in statistical analysis. Results: (1) The anatomic course of the CS in relation to the mitral ring was straight, mild curvature and high riding of 62, 16 and 18 cases in control group and 10, 8 and 30 cases in AF group,respectively. There was not statistical significance between the 2 group (χ2=0.093, P=0.954). (2) The CS length was (34.1 ±9.1), (33.8 ±8.9)mm in Control group and AF group,respectively. There was no statistical significance between the 2 group (t=-0.486, P=0.628). (3) Coronary sinus-left atrium muscle connections were seen in 131 of the 144 patients (91.0%). A single connection was seen in 103 of the 144 patients, with a mean length of (22.6 ± 12.7) mm within (6.3 ± 5.8) mm of the coronary sinus ostium. 28 patients had two connections; distal connections measured (13.2 ± 6.2) mm in length within (16.7 ± 6.8) mm of the coronary sinus ostium,and proximal connections measured (11.1 ± 3.6) mm in length within (2.1 ± 1.9) mm of the coronary sinus ostium.And there was no statistical difference the number and length of CS-left atrium connections in between Control group and AF group (P>0.05). (4) The CS narrowed 22

  8. Internalization and desensitization of adenosine receptors

    Klaasse, Elisabeth C.; IJzerman, Adriaan P.; de Grip, Willem J.; Beukers, Margot W.

    2007-01-01

    Until now, more than 800 distinct G protein-coupled receptors (GPCRs) have been identified in the human genome. The four subtypes of the adenosine receptor (A1, A2A, A2B and A3 receptor) belong to this large family of GPCRs that represent the most widely targeted pharmacological protein class. Since adenosine receptors are widespread throughout the body and involved in a variety of physiological processes and diseases, there is great interest in understanding how the different subtypes are re...

  9. 21 CFR 864.7040 - Adenosine triphosphate release assay.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Adenosine triphosphate release assay. 864.7040 Section 864.7040 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Adenosine triphosphate release assay. (a) Identification. An adenosine triphosphate release assay is...

  10. Study of Ectonucleotidases and Adenosine Deaminases in Drosophila

    PREUER, Kristina

    2013-01-01

    Extracellular adenosine triphosphate and extracellular adenosine are important regulatory molecules in the human immune system. The concentrations of these molecules are in turn regulated by ectonucleotidases and adenosine deaminases. In this thesis I attempt to test the gene silencing efficiency of RNA interference for three different genes coding for such enzymes in the model organism Drosophila melanogaster.

  11. Dual-source cardiac computed tomography angiography (CCTA) in the follow-up of cardiac transplant: comparison of image quality and radiation dose using three different imaging protocols

    To prospectively evaluate image quality (IQ) and radiation dose of dual-source cardiac computed tomography (CCTA) using different imaging protocols. CCTA was performed in 150 patients using the retrospective ECG-gated spiral technique (rECG) the prospective ECG-gated technique (pECG), or the prospective ECG-gated technique with systolic imaging and automated tube voltage selection (pECGsys). IQ was rated using a 16-segment coronary artery model. Techniques were compared for overall IQ, IQ of the large and the small coronary artery segments. Effective dose was used for comparison of radiation dose. Overall IQ and IQ of the large segments showed no differences between the groups. IQ analysis of the small segments showed lowered IQ in pECGsys compared to rECG (p = 0.02), but not to pECG (p = 0.6). Effective dose did not differ significantly between rECG and pECG (p = 0.13), but was significantly lower for pECGsys (p < 0.001 vs. rECG and pECG). Radiation dose of dual-source CCTA in heart transplant recipients is significantly reduced by using prospective systolic scanning and automated tube voltage selection, while overall IQ and IQ of the large coronary segments are maintained. IQ appears to be lower compared to retrospective techniques with regard to small coronary segments. (orig.)

  12. Image quality and radiation dose of low tube voltage 3rd generation dual-source coronary CT angiography in obese patients: a phantom study

    To assess the influence of tube potential on radiation dose and image quality of third-generation dual-source coronary CT angiography (CTA) in a phantom simulating an obese patient. A thoracic phantom was equipped with tubular inserts containing iodine solution and water. A soft-tissue-equivalent ring around the phantom simulated an obese patient. Images were acquired at tube potentials of 80, 100, 120 and 140 kV with second-generation dual-source CT (DSCT) and 70-150 kV (in 10-kV increments) with third-generation DSCT. Contrast-to-noise ratio (CNR) was calculated and CT dose index was recorded. With second-generation DSCT, CNR was highest for 120 kV (19.0) and decreased with lower tube potential (12.0 at 80 kV) owing to disproportionately increased image noise. With third-generation DSCT, 70- and 80-kV acquisitions showed a smaller increase in noise. CNRs for third-generation DSCT were highest for 70 and 80 kV (21.1 and 21.2, respectively). Compared to 120 kV, radiation dose was 68 % and 49 % lower at 70 kV and 80 kV, respectively. Third-generation DSCT enables one to perform coronary CTA at 70-80 kV in obese patients without compromising CNR and thus reduces radiation dose by 49-68 %. (orig.)

  13. Dual-source chest CT angiography with high temporal resolution and high pitch modes: evaluation of image quality in 140 patients

    Tacelli, Nunzia; Remy-Jardin, Martine; Faivre, Jean-Baptiste; Remy, Jacques [University Centre of Lille (EA 2694), Department of Thoracic Imaging, Hospital Calmette, Lille (France); Flohr, Thomas [Siemens Healthcare, Computed Tomography, Forchheim (Germany); Delannoy, Valerie; Duhamel, Alain [University Centre of Lille (EA 2694), Department of Biostatistics, Lille (France)

    2010-05-15

    To evaluate image quality of dual-source computed tomography (CT) angiograms acquired with high temporal resolution and high pitch modes. Two groups of 70 consecutive patients underwent chest CT angiography with dual-source, single-energy CT, with an 83-ms temporal resolution and a pitch of 2 (group 1) or a pitch of 3 (group 2). Subjective and objective image quality and the diagnostic value were assessed by two radiologists in consensus. The radiation dose was recorded. The image quality was always diagnostic in both groups, rated as excellent in 97% of group 1 (68/70) and 98.5% of group 2 (69/70) examinations. Although no statistically significant difference in subjective image noise was found between the two groups (p = 0.3055), objective noise was found to be statistically higher in group 2 (p<0.0001). The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were found to be significantly higher in group 1 than in group 2 (p=0.0014). The acquisition time was significantly shorter in group 2 than in group 1 (p<0.0001). The dose-length product was significantly lower in group 2 than in group 1 (p < 0.0001). High temporal resolution and high pitch modes provided standard CT angiographic examinations of excellent quality for thoracic applications in routine clinical practice. (orig.)

  14. Image quality and radiation dose of low tube voltage 3{sup rd} generation dual-source coronary CT angiography in obese patients: a phantom study

    Meinel, Felix G. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Ludwig-Maximilians-University Hospital, Institute for Clinical Radiology, Munich (Germany); Canstein, Christian [Siemens Medical Solutions USA, Malvern, PA (United States); Schoepf, U.J. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Medical University of South Carolina, Department of Medicine, Division of Cardiology, Charleston, SC (United States); Sedlmaier, Martin; Schmidt, Bernhard; Flohr, Thomas G. [Siemens Healthcare, Computed Tomography Division, Forchheim (Germany); Harris, Brett S. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); De Cecco, Carlo N. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); University of Rome ' ' Sapienza' ' , Department of Radiological Sciences, Oncology and Pathology, Polo Pontino, Latina (Italy)

    2014-07-15

    To assess the influence of tube potential on radiation dose and image quality of third-generation dual-source coronary CT angiography (CTA) in a phantom simulating an obese patient. A thoracic phantom was equipped with tubular inserts containing iodine solution and water. A soft-tissue-equivalent ring around the phantom simulated an obese patient. Images were acquired at tube potentials of 80, 100, 120 and 140 kV with second-generation dual-source CT (DSCT) and 70-150 kV (in 10-kV increments) with third-generation DSCT. Contrast-to-noise ratio (CNR) was calculated and CT dose index was recorded. With second-generation DSCT, CNR was highest for 120 kV (19.0) and decreased with lower tube potential (12.0 at 80 kV) owing to disproportionately increased image noise. With third-generation DSCT, 70- and 80-kV acquisitions showed a smaller increase in noise. CNRs for third-generation DSCT were highest for 70 and 80 kV (21.1 and 21.2, respectively). Compared to 120 kV, radiation dose was 68 % and 49 % lower at 70 kV and 80 kV, respectively. Third-generation DSCT enables one to perform coronary CTA at 70-80 kV in obese patients without compromising CNR and thus reduces radiation dose by 49-68 %. (orig.)

  15. Dual-source cardiac computed tomography angiography (CCTA) in the follow-up of cardiac transplant: comparison of image quality and radiation dose using three different imaging protocols

    Beitzke, D.; Berger-Kulemann, V.; Unterhumer, S.; Loewe, C.; Wolf, F. [Medical University Vienna, Department of Biomedical Imaging and Image Guided Therapy, Division of Cardiovascular and Interventional Radiology, Vienna (Austria); Schoepf, V. [Medical University Vienna, Department of Biomedical Imaging and Image Guided Therapy, Division of Neuroradiology and Musculoskeletal Radiology, Vienna (Austria); Spitzer, E. [Bern University Hospital, Department of Cardiology, Bern (Switzerland); Feuchtner, G.M. [Innsbruck Medical University, Department of Radiology II, Innsbruck (Austria); Gyoengyoesi, M. [Medical University Vienna, Department of Cardiology, Vienna (Austria); Uyanik-Uenal, K.; Zuckermann, A. [Medical University Vienna, Department of Cardiac Surgery, Vienna (Austria)

    2015-08-15

    To prospectively evaluate image quality (IQ) and radiation dose of dual-source cardiac computed tomography (CCTA) using different imaging protocols. CCTA was performed in 150 patients using the retrospective ECG-gated spiral technique (rECG) the prospective ECG-gated technique (pECG), or the prospective ECG-gated technique with systolic imaging and automated tube voltage selection (pECGsys). IQ was rated using a 16-segment coronary artery model. Techniques were compared for overall IQ, IQ of the large and the small coronary artery segments. Effective dose was used for comparison of radiation dose. Overall IQ and IQ of the large segments showed no differences between the groups. IQ analysis of the small segments showed lowered IQ in pECGsys compared to rECG (p = 0.02), but not to pECG (p = 0.6). Effective dose did not differ significantly between rECG and pECG (p = 0.13), but was significantly lower for pECGsys (p < 0.001 vs. rECG and pECG). Radiation dose of dual-source CCTA in heart transplant recipients is significantly reduced by using prospective systolic scanning and automated tube voltage selection, while overall IQ and IQ of the large coronary segments are maintained. IQ appears to be lower compared to retrospective techniques with regard to small coronary segments. (orig.)

  16. Internalization and desensitization of adenosine receptors.

    Klaasse, E.C.; IJzerman, A.P.; Grip, W.J. de; Beukers, M.W.

    2008-01-01

    Until now, more than 800 distinct G protein-coupled receptors (GPCRs) have been identified in the human genome. The four subtypes of the adenosine receptor (A(1), A(2A), A(2B) and A(3) receptor) belong to this large family of GPCRs that represent the most widely targeted pharmacological protein clas

  17. Effects of adenosine infusion into renal interstitium on renal hemodynamics

    This study was designed to investigate the hemodynamic effects of exogenous adenosine in the interstitium of the rat kidney. Adenosine or its analogues were infused into the renal interstitium by means of chronically implanted capsules. In fusion of adenosine decreased glomerular filtration rate (GFR) from 0.81 +/- 0.06 to 0.37 +/- 0.06 ml/min while having no effect on renal blood flow (RBF). The metabolically stable analogue, 2-chloradenosine (2-ClAdo), decreased GFR from 0.73 +/- 0.07 to 021 +/- 0.06 ml/min. Interstitial infusion of theophylline, an adenosine receptor antagonist, completely abolished the effects of adenosine and 2-ClAdo on GFR. The distribution of adenosine, when infused into the renal interstitium, was determined using radiolabeled 5'-(N-ethyl)-carboxamidoadenosine (NECA), a metabolically stable adenosine agonist. After continuous infusion, [3H]NECA was distributed throughout the kidney. The effects of NECA to reduce GFR were similar to those of adenosine and 2-ClAdo. They conclude that increased levels of adenosine in the renal interstitium markedly decrease GFR without affecting RBF in steady-state conditions. The marked effects of adenosine agonists during their infusion into the renal interstitium and the complete blockade of these effects by theophylline suggest an extracellular action of adenosine

  18. Adenosine: An immune modulator of inflammatory bowel diseases

    Jeff Huaqing Ye; Vazhaikkurichi M Rajendran

    2009-01-01

    Inflammatory bowel disease (IBD) is a common and lifelong disabling gastrointestinal disease. Emerging treatments are being developed to target inflammatory cytokines which initiate and perpetuate the immune response. Adenosine is an important modulator of inflammation and its anti-inflammatory effects have been well established in humans as well as in animal models. High extracellular adenosine suppresses and resolves chronic inflammation in IBD models. High extracellular adenosine levels could be achieved by enhanced adenosine absorption and increased de novo synthesis. Increased adenosine concentration leads to activation of the A2a receptor on the cell surface of immune and epithelial cells that would be a potential therapeutic target for chronic intestinal inflammation. Adenosine is transported via concentrative nucleoside transporter and equilibrative nucleoside transporter transporters that are localized in apical and basolateral membranes of intestinal epithelial cells, respectively. Increased extracellular adenosine levels activate the A2a receptor, which would reduce cytokines responsible for chronic inflammation.

  19. Conversion of the energy-subtracted CT number to electron density based on a single linear relationship: an experimental verification using a clinical dual-source CT scanner

    Tsukihara, Masayoshi; Noto, Yoshiyuki; Hayakawa, Takahide; Saito, Masatoshi

    2013-05-01

    In radiotherapy treatment planning, the conversion of the computed tomography (CT) number to electron density is one of the main processes that determine the accuracy of patient dose calculations. However, in general, the CT number and electron density of tissues cannot be interrelated using a simple one-to-one correspondence. This study aims to experimentally verify the clinical feasibility of an existing novel conversion method proposed by the author of this note, which converts the energy-subtracted CT number (ΔHU) to the relative electron density (ρe) via a single linear relationship by using a dual-energy CT (DECT). The ΔHU-ρe conversion was performed using a clinical second-generation dual-source CT scanner operated in the dual-energy mode with tube potentials of 80 kV and 140 kV with and without an additional tin filter. The ΔHU-ρe calibration line was obtained from the DECT image acquisition for tissue substitutes in an electron density phantom. In addition, the effect of object size on ΔHU-ρe conversion was also experimentally investigated. The plot of the measured ΔHU versus nominal ρe values exhibited a single linear relationship over a wide ρe range from 0.00 (air) to 2.35 (aluminum). The ΔHU-ρe conversion performed with the tin filter yielded a lower dose and more reliable ρe values that were less affected by the object-size variation when compared to the corresponding values obtained for the case without the tin filter.

  20. Lack of effect of adenosine on the function of rodent osteoblasts and osteoclasts in vitro.

    Hajjawi, Mark O R; Patel, Jessal J; Corcelli, Michelangelo; Arnett, Timothy R; Orriss, Isabel R

    2016-06-01

    Extracellular ATP, signalling through P2 receptors, exerts well-documented effects on bone cells, inhibiting mineral deposition by osteoblasts and stimulating the formation and resorptive activity of osteoclasts. The aims of this study were to determine the potential osteotropic effects of adenosine, the hydrolysis product of ATP, on primary bone cells in vitro. We determined the effect of exogenous adenosine on (1) the growth, alkaline phosphatase (TNAP) activity and bone-forming ability of osteoblasts derived from the calvariae of neonatal rats and mice and the marrow of juvenile rats and (2) the formation and resorptive activity of osteoclasts from juvenile mouse marrow. Reverse transcription polymerase chain reaction (RT-PCR) analysis showed marked differences in the expression of P1 receptors in osteoblasts from different sources. Whilst mRNA for the A1 and A2B receptors was expressed by all primary osteoblasts, A2A receptor expression was limited to rat bone marrow and mouse calvarial osteoblasts and the A3 receptor to rat bone marrow osteoblasts. We found that adenosine had no detectable effects on cell growth, TNAP activity or bone formation by rodent osteoblasts in vitro. The analogue 2-chloroadenosine, which is hydrolysed more slowly than adenosine, had no effects on rat or mouse calvarial osteoblasts but increased TNAP activity and bone formation by rat bone marrow osteoblasts by 30-50 % at a concentration of 1 μM. Osteoclasts were found to express the A2A, A2B and A3 receptors; however, neither adenosine (≤100 μM) nor 2-chloroadenosine (≤10 μM) had any effect on the formation or resorptive activity of mouse osteoclasts in vitro. These results suggest that adenosine, unlike ATP, is not a major signalling molecule in the bone. PMID:26861849

  1. Evaluation of dual-source parallel RF excitation for diffusion-weighted whole-body MR imaging with background body signal suppression at 3.0 T

    Muertz, Petra, E-mail: petra.muertz@ukb.uni-bonn.de [Department of Radiology, University of Bonn (Germany); Kaschner, Marius, E-mail: marius.kaschner@ukb.uni-bonn.de [Department of Radiology, University of Bonn (Germany); Traeber, Frank, E-mail: frank.traeber@ukb.uni-bonn.de [Department of Radiology, University of Bonn (Germany); Kukuk, Guido M., E-mail: guido.kukuk@ukb.uni-bonn.de [Department of Radiology, University of Bonn (Germany); Buedenbender, Sarah M., E-mail: sarah_m_buedenbender@yahoo.de [Department of Radiology, University of Bonn (Germany); Skowasch, Dirk, E-mail: dirk.skowasch@ukb.uni-bonn.de [Department of Medicine, University of Bonn (Germany); Gieseke, Juergen, E-mail: juergen.gieseke@philips.com [Philips Healthcare, Best (Netherlands); Department of Radiology, University of Bonn (Germany); Schild, Hans H., E-mail: hans.schild@ukb.uni-bonn.de [Department of Radiology, University of Bonn (Germany); Willinek, Winfried A., E-mail: winfried.willinek@ukb.uni-bonn.de [Department of Radiology, University of Bonn (Germany)

    2012-11-15

    Purpose: To evaluate the use of dual-source parallel RF excitation (TX) for diffusion-weighted whole-body MRI with background body signal suppression (DWIBS) at 3.0 T. Materials and methods: Forty consecutive patients were examined on a clinical 3.0-T MRI system using a diffusion-weighted (DW) spin-echo echo-planar imaging sequence with a combination of short TI inversion recovery and slice-selective gradient reversal fat suppression. DWIBS of the neck (n = 5), thorax (n = 8), abdomen (n = 6) and pelvis (n = 21) was performed both with TX (2:56 min) and with standard single-source RF excitation (4:37 min). The quality of DW images and reconstructed inverted maximum intensity projections was visually judged by two readers (blinded to acquisition technique). Signal homogeneity and fat suppression were scored as 'improved', 'equal', 'worse' or 'ambiguous'. Moreover, the apparent diffusion coefficient (ADC) values were measured in muscles, urinary bladder, lymph nodes and lesions. Results: By the use of TX, signal homogeneity was 'improved' in 25/40 and 'equal' in 15/40 cases. Fat suppression was 'improved' in 17/40 and 'equal' in 23/40 cases. These improvements were statistically significant (p < 0.001, Wilcoxon signed-rank test). In five patients, fluid-related dielectric shading was present, which improved remarkably. The ADC values did not significantly differ for the two RF excitation methods (p = 0.630 over all data, pairwise Student's t-test). Conclusion: Dual-source parallel RF excitation improved image quality of DWIBS at 3.0 T with respect to signal homogeneity and fat suppression, reduced scan time by approximately one-third, and did not influence the measured ADC values.

  2. SU-D-207-03: Development of 4D-CBCT Imaging System with Dual Source KV X-Ray Tubes

    Purpose: The purposes of this work are to develop 4D-CBCT imaging system with orthogonal dual source kV X-ray tubes, and to determine the imaging doses from 4D-CBCT scans. Methods: Dual source kV X-ray tubes were used for the 4D-CBCT imaging. The maximum CBCT field of view was 200 mm in diameter and 150 mm in length, and the imaging parameters were 110 kV, 160 mA and 5 ms. The rotational angle was 105°, the rotational speed of the gantry was 1.5°/s, the gantry rotation time was 70 s, and the image acquisition interval was 0.3°. The observed amplitude of infrared marker motion during respiration was used to sort each image into eight respiratory phase bins. The EGSnrc/BEAMnrc and EGSnrc/DOSXYZnrc packages were used to simulate kV X-ray dose distributions of 4D-CBCT imaging. The kV X-ray dose distributions were calculated for 9 lung cancer patients based on the planning CT images with dose calculation grid size of 2.5 x 2.5 x 2.5 mm. The dose covering a 2-cc volume of skin (D2cc), defined as the inner 5 mm of the skin surface with the exception of bone structure, was assessed. Results: A moving object was well identified on 4D-CBCT images in a phantom study. Given a gantry rotational angle of 105° and the configuration of kV X-ray imaging subsystems, both kV X-ray fields overlapped at a part of skin surface. The D2cc for the 4D-CBCT scans was in the range 73.8–105.4 mGy. Linear correlation coefficient between the 1000 minus averaged SSD during CBCT scanning and D2cc was −0.65 (with a slope of −0.17) for the 4D-CBCT scans. Conclusion: We have developed 4D-CBCT imaging system with dual source kV X-ray tubes. The total imaging dose with 4D-CBCT scans was up to 105.4 mGy

  3. SU-D-207-03: Development of 4D-CBCT Imaging System with Dual Source KV X-Ray Tubes

    Nakamura, M; Ishihara, Y; Matsuo, Y; Ueki, N; Iizuka, Y; Mizowaki, T; Hiraoka, M [Kyoto University Hospital, Kyoto, Kyoto (Japan)

    2015-06-15

    Purpose: The purposes of this work are to develop 4D-CBCT imaging system with orthogonal dual source kV X-ray tubes, and to determine the imaging doses from 4D-CBCT scans. Methods: Dual source kV X-ray tubes were used for the 4D-CBCT imaging. The maximum CBCT field of view was 200 mm in diameter and 150 mm in length, and the imaging parameters were 110 kV, 160 mA and 5 ms. The rotational angle was 105°, the rotational speed of the gantry was 1.5°/s, the gantry rotation time was 70 s, and the image acquisition interval was 0.3°. The observed amplitude of infrared marker motion during respiration was used to sort each image into eight respiratory phase bins. The EGSnrc/BEAMnrc and EGSnrc/DOSXYZnrc packages were used to simulate kV X-ray dose distributions of 4D-CBCT imaging. The kV X-ray dose distributions were calculated for 9 lung cancer patients based on the planning CT images with dose calculation grid size of 2.5 x 2.5 x 2.5 mm. The dose covering a 2-cc volume of skin (D2cc), defined as the inner 5 mm of the skin surface with the exception of bone structure, was assessed. Results: A moving object was well identified on 4D-CBCT images in a phantom study. Given a gantry rotational angle of 105° and the configuration of kV X-ray imaging subsystems, both kV X-ray fields overlapped at a part of skin surface. The D2cc for the 4D-CBCT scans was in the range 73.8–105.4 mGy. Linear correlation coefficient between the 1000 minus averaged SSD during CBCT scanning and D2cc was −0.65 (with a slope of −0.17) for the 4D-CBCT scans. Conclusion: We have developed 4D-CBCT imaging system with dual source kV X-ray tubes. The total imaging dose with 4D-CBCT scans was up to 105.4 mGy.

  4. Comparison of dual-source CT angiography and MR angiography in preoperative evaluation of intra- and extracranial vessels: a pilot study

    Besides the assessment of carotid artery stenosis, evaluation of the vascular anatomy and lesions within both the extra- and intracranial arteries is crucial for proper clinical evaluation, treatment choice and planning. The purpose of our study was to evaluate the potential of dual-source CTA and 3T-MRA. In 16 symptomatic CAS patients, contrast-enhanced DSCT and 3T-MRA examinations were performed. For DSCT a dual-energy protocol with a 64 x 0.6-mm collimation was applied. In 3T-MRA intracranial high-resolution unenhanced TOF and extracranial contrast-enhanced MRA were performed. All examinations were analyzed for relevant morphologic and pathologic features or anomalies, and a total of 624 vessel segments were scored. All examinations were of diagnostic image quality with good to excellent vessel visibility. Almost all intracranial arteries were significantly better visualized by MRA compared to CTA (five of six vessels, p < 0.05). DSCT however allowed for further morphological carotid stenosis description, especially with respect to calcification. Although MRA proved to be superior in visualization of smaller intracranial arteries, all pre-interventionally relevant information could be perceived from DSCT. DSCT and MRA may both be regarded as a reliable, fast, pre-interventional imaging investigation in patients with carotid artery stenosis. (orig.)

  5. Comparison of dual-source CT angiography and MR angiography in preoperative evaluation of intra- and extracranial vessels: a pilot study

    Muehlenbruch, Georg; Das, Marco; Mahnken, Andreas Horst; Guenther, Rolf W. [RWTH Aachen University, Department of Diagnostic and Interventional Radiology, Aachen (Germany); Mommertz, Gottfried; Langer, Stefan [RWTH Aachen University, Department of Vascular Surgery, Aachen (Germany); Schaaf, Meike; Thron, A.; Krings, Timo [RWTH Aachen University, Department of Neuroradiology, Aachen (Germany); Wildberger, Joachim Ernst [University Hospital Maastricht, Department of Radiology, Maastricht (Netherlands)

    2010-02-15

    Besides the assessment of carotid artery stenosis, evaluation of the vascular anatomy and lesions within both the extra- and intracranial arteries is crucial for proper clinical evaluation, treatment choice and planning. The purpose of our study was to evaluate the potential of dual-source CTA and 3T-MRA. In 16 symptomatic CAS patients, contrast-enhanced DSCT and 3T-MRA examinations were performed. For DSCT a dual-energy protocol with a 64 x 0.6-mm collimation was applied. In 3T-MRA intracranial high-resolution unenhanced TOF and extracranial contrast-enhanced MRA were performed. All examinations were analyzed for relevant morphologic and pathologic features or anomalies, and a total of 624 vessel segments were scored. All examinations were of diagnostic image quality with good to excellent vessel visibility. Almost all intracranial arteries were significantly better visualized by MRA compared to CTA (five of six vessels, p < 0.05). DSCT however allowed for further morphological carotid stenosis description, especially with respect to calcification. Although MRA proved to be superior in visualization of smaller intracranial arteries, all pre-interventionally relevant information could be perceived from DSCT. DSCT and MRA may both be regarded as a reliable, fast, pre-interventional imaging investigation in patients with carotid artery stenosis. (orig.)

  6. 双源CT双能量胸部虚拟平扫的应用价值%Application of dual energy virtual non-contrast CT of dual source CT in thorax

    江杰; 何波; 张俊; 韩丹

    2012-01-01

    To investigate the clinical feasibility of dual energy virtual non-contrast CT (VNC) of dual source CT in the thorax in comparison with conventional plain scan. Methods In total of 155 patients suspected with thorax diseases were performed conventional plain scan and dual energy enhanced scan. VNC images were obtained through post-processing. Mean CT values, SNR, image quality, detectability of lesions and radiation dosage were compared between the conventional plain scan and VNC. Results In VNC images, mean CT value in pulmonary artery trunk was higher than conventional plain scan (P0. 05). SNR of VNC was higher than that of conventional plain scan (P0. 05). VNC and conventional plain scan had similar performance for the detection of lesions, except some calcified lesions (6/21) and small lymph nodes (3/37) near the superior vena cava were not identified in VNC, while the other lesions can be shown. The radiation dosage of VNC were slightly higher than conventional plain scan (P<0. 05). Conclusion Dual energy enhanced scan in the thorax could get enhanced images and VNC images in one scan. VNC images could not affect image quality and detectability of lesions, significantly reduce the radiation dosage, which has a potential clinical value in the thorax.%目的 通过对比胸部常规平扫与双源CT双能量虚拟平扫(VNC),探讨VNC临床应用的可行性.方法 对155例怀疑胸部疾病的患者行常规CT平扫和双能CT增强扫描,后处理得到VNC图像,对VNC和常规平扫平均CT值、SNR、图像质量、病灶显示情况、辐射剂量等方面进行比较.结果 肺动脉干处平均CT值VNC高于常规平扫(P<0.05),而左心室及脊柱后方肌肉处差异均无统计学意义(P均>0.05). VNC ROI选在肺动脉干、左心室、脊柱后方肌肉的图像SNR均高于常规平扫(P<0.05). VNC图像质量与常规平扫比较差异无统计学意义(P>0.05).VNC的病灶显示情况类似,除部分钙化灶(6/21)

  7. Quantification of left and right ventricular function and myocardial mass: Comparison of low-radiation dose 2nd generation dual-source CT and cardiac MRI

    Objective: To prospectively evaluate the accuracy of left and right ventricular function and myocardial mass measurements based on a dual-step, low radiation dose protocol with prospectively ECG-triggered 2nd generation dual-source CT (DSCT), using cardiac MRI (cMRI) as the reference standard. Materials and methods: Twenty patients underwent 1.5 T cMRI and prospectively ECG-triggered dual-step pulsing cardiac DSCT. This image acquisition mode performs low-radiation (20% tube current) imaging over the majority of the cardiac cycle and applies full radiation only during a single adjustable phase. Full-radiation-phase images were used to assess cardiac morphology, while low-radiation-phase images were used to measure left and right ventricular function and mass. Quantitative CT measurements based on contiguous multiphase short-axis reconstructions from the axial CT data were compared with short-axis SSFP cardiac cine MRI. Contours were manually traced around the ventricular borders for calculation of left and right ventricular end-diastolic volume, end-systolic volume, stroke volume, ejection fraction and myocardial mass for both modalities. Statistical methods included independent t-tests, the Mann–Whitney U test, Pearson correlation statistics, and Bland–Altman analysis. Results: All CT measurements of left and right ventricular function and mass correlated well with those from cMRI: for left/right end-diastolic volume r = 0.885/0.801, left/right end-systolic volume r = 0.947/0.879, left/right stroke volume r = 0.620/0.697, left/right ejection fraction r = 0.869/0.751, and left/right myocardial mass r = 0.959/0.702. Mean radiation dose was 6.2 ± 1.8 mSv. Conclusions: Prospectively ECG-triggered, dual-step pulsing cardiac DSCT accurately quantifies left and right ventricular function and myocardial mass in comparison with cMRI with substantially lower radiation exposure than reported for traditional retrospective ECG-gating.

  8. Dual-source dual-energy CT for the differentiation of urinary stone composition: preliminary study%双源CT双能量成像对泌尿系统结石成分分析的初步研究

    杨琪放; 严景民; 张挽时; 孟利民; 时惠平; 王东; 毕永民; 李相生; 方红; 郭和清

    2011-01-01

    氨酸结石、混合尿酸结石与其他类型结石.%Objective To evaluate dual-source dual-energy CT(DSCT) for the differentiation of urinary stone composition in vitro. Methods Ninety-seven urinary stones were obtained by endoscopic lithotripsy and scanned using dual-source dual-energy CT. The stones were divided into six groups according to infrared spectroscopy stone analysis: uric acid ( UA ) stones ( n = 10 ), cystine stones ( n = 5 ), struvite stones( n = 6), calcium oxalate ( CaOx ) stones ( n = 22 ), mixed UA stones ( n=7 ) and mixed calcium stones(n=47). Hounsfield units (HU) of each stone were recorded for the 80 kV and the 140 kV datasets by hand-drawing method. HU difference, HU ratio and dual energy index ( DEI ) were calculated and compared among the stone groups with one-way ANOVA. Using dual energy software to determine the composition of all stones, results were compared to infrared spectroscopy analysis. Results There were statistical differences in HU difference [(-17±13), (229±34),(309 ±45), (512 ±97), (201±64)and (530±71) HU respectively], in HU ratio (0.96±0.03, 1.34 ±0.04, 1.41 ±0.03, 1.47 ±0.03,1.30±0.07, and 1.49 ±0.03 respectively), and DEI( -0.006 ±0.004, 0.064 ±0.007, 0.080 ±0. 007, 0. 108±0.011 ,0. 055 ±0.014 and 0. 112 ±0.008 respectively ) among different stone groups(F=124. 894,407.028, 322. 864 respectively, P <0. 01 ). There were statistical differences in HU difference,HU ratio and DE1 between UA stones and the other groups( P < 0. 01 ). There were statistical differences in HU difference, HU ratio and DEI between CaOx or mixed calcium stones and the other four groups (P<0. 01 ). There was statistical difference in HU ratio between cystine and struvite stones ( P < 0. 01 ). There were statistical differences in HU difference, HU ratio and DEI between struvite and mixed UA stones (P<0. 05 ). Dual energy software correctly characterized 10 UA stones, 4 cystine stones, 22 CaOx stones and 6 mixed UA

  9. Dual-frequency comb generation with differing GHz repetition rates by parallel Fabry–Perot cavity filtering of a single broadband frequency comb source

    Mildner, Jutta; Meiners-Hagen, Karl; Pollinger, Florian

    2016-07-01

    We present a dual-comb-generator based on a coupled Fabry–Perot filtering cavity doublet and a single seed laser source. By filtering a commercial erbium-doped fiber-based optical frequency comb with CEO-stabilisation and 250 MHz repetition rate, two broadband coherent combs of different repetition rates in the GHz range are generated. The filtering doublet consists of two Fabry–Perot cavities with a tunable spacing and Pound–Drever–Hall stabilisation scheme. As a prerequisite for the development of such a filtering unit, we present a method to determine the actual free spectral range and transmission bandwidth of a Fabry–Perot cavity in situ. The transmitted beat signal of two diode lasers is measured as a function of their tunable frequency difference. Finally, the filtering performance and resulting beat signals of the heterodyned combs are discussed as well as the optimisation measures of the whole system.

  10. The value of coronary artery calcium score assessed by dual-source computed tomography coronary angiography for predicting presence and severity of coronary artery disease

    Measuring coronary artery calcium score (CACS) using a dual-source CT scanner is recognized as a major indicator for assessing coronary artery disease. The present study aimed to validate the clinical significance of CACS in predicting coronary artery stenosis and its severity. This prospective study was conducted on 202 consecutive patients who underwent both conventional coronary angiography and dual-source (256-slice) computed tomography coronary angiography (CTA) for any reason in our cardiac imaging center from March to September 2013. CACS was measured by Agatston algorithm on non-enhanced CT. The severity of coronary artery disease was assessed by Gensini score on conventional angiography. There was a significant relationship between the number of diseased coronary vessels and mean calcium score, i.e. the mean calcium score was 202.25±450.06 in normal coronary status, 427.50±607.24 in single-vessel disease, 590.03±511.34 in two-vessel disease, and 953.35±1023.45 in three-vessel disease (p<0.001). There was a positive association between calcium score and Gensini score (r=0.636, p<0.001). In a linear regression model, calcium score was a strong determinant of the severity of coronary artery disease. Calcium scoring had an acceptable value for discriminating coronary disease from normal condition with optimal cutoff point of 350, yielding a sensitivity and specificity of 83% and 70%, respectively. Our study confirmed the strong relationship between the coronary artery calcium score and the presence and severity of stenosis in coronary arteries assessed by both the number of diseased coronary vessels and also by the Gnesini score