WorldWideScience

Sample records for echocardiography four-dimensional

  1. Three- and four-dimensional ultrasound in fetal echocardiography: an up-to-date overview.

    Science.gov (United States)

    Adriaanse, B M E; van Vugt, J M G; Haak, M C

    2016-09-01

    Congenital heart diseases (CHD) are the most commonly overlooked lesions in prenatal screening programs. Real-time two-dimensional ultrasound (2DUS) is the conventionally used tool for fetal echocardiography. Although continuous improvements in the hardware and post-processing software have resulted in a good image quality even in late first trimester, 2DUS still has its limitations. Four-dimensional ultrasound with spatiotemporal image correlation (STIC) is an automated volume acquisition, recording a single three-dimensional (3D) volume throughout a complete cardiac cycle, which results in a four-dimensional (4D) volume. STIC has the potential to increase the detection rate of CHD. The aim of this study is to provide a practical overview of the possibilities and (dis)advantages of STIC. A review of literature and evaluation of the current status and clinical value of 3D/4D ultrasound in prenatal screening and diagnosis of congenital heart disease are presented.

  2. Four-dimensional echocardiography area strain combined with exercise stress echocardiography to evaluate left ventricular regional systolic function in patients with mild single vessel coronary artery stenosis.

    Science.gov (United States)

    Deng, Yan; Peng, Long; Liu, Yuan-Yuan; Yin, Li-Xue; Li, Chun-Mei; Wang, Yi; Rao, Li

    2017-07-28

    The aim of this prospective study was to assess the diagnosis value of four-dimensional echocardiography area strain (AS) combined with exercise stress echocardiography to evaluate left ventricular regional systolic function in patients with mild single vessel coronary artery stenosis. Based on treadmill exercise load status, two-dimensional conventional echocardiography and four-dimensional echocardiography area strain were performed on patients suspected coronary artery disease before coronary angiogram. Thirty patients (case group) with mild left anterior descending coronary artery stenosis (stenosis coronary artery stenosis according to the coronary angiogram results were prospectively enrolled. All the patients had no left ventricular regional wall motion abnormality in two-dimensional echocardiography at rest and exercise stress. There was no significant difference in the 16 segmental systolic peak AS at rest between two groups. After exercise stress, the peak systolic ASrest-stress at mid anterior wall (-7.00%±10.90% vs 2.80%±23.69%) and mid anterolateral wall (-4.40%±18.81% vs 8.80%±19.16%) were decreased, while increased at basal inferolateral wall (14.00%±19.27% vs -5.60%±15.94%) in case group compared with control group (Pcoronary artery stenosis, the area strain was decreased at involved segments, while compensatory increased at noninvolved segments after exercise stress. Four-dimensional echocardiography area strain combined with exercise stress echocardiography could sensitively find left ventricular regional systolic function abnormality in patients with mild single vessel coronary artery stenosis, and locate stenosis coronary artery accordingly. © 2017, Wiley Periodicals, Inc.

  3. Four Dimensional Trace Space Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, M.

    2005-02-10

    Future high energy colliders and FELs (Free Electron Lasers) such as the proposed LCLS (Linac Coherent Light Source) at SLAC require high brightness electron beams. In general a high brightness electron beam will contain a large number of electrons that occupy a short longitudinal duration, can be focused to a small transverse area while having small transverse divergences. Therefore the beam must have a high peak current and occupy small areas in transverse phase space and so have small transverse emittances. Additionally the beam should propagate at high energy and have a low energy spread to reduce chromatic effects. The requirements of the LCLS for example are pulses which contain 10{sup 10} electrons in a temporal duration of 10 ps FWHM with projected normalized transverse emittances of 1{pi} mm mrad[1]. Currently the most promising method of producing such a beam is the RF photoinjector. The GTF (Gun Test Facility) at SLAC was constructed to produce and characterize laser and electron beams which fulfill the LCLS requirements. Emittance measurements of the electron beam at the GTF contain evidence of strong coupling between the transverse dimensions of the beam. This thesis explores the effects of this coupling on the determination of the projected emittances of the electron beam. In the presence of such a coupling the projected normalized emittance is no longer a conserved quantity. The conserved quantity is the normalized full four dimensional phase space occupied by the beam. A method to determine the presence and evaluate the strength of the coupling in emittance measurements made in the laboratory is developed. A method to calculate the four dimensional volume the beam occupies in phase space using quantities available in the laboratory environment is also developed. Results of measurements made of the electron beam at the GTF that demonstrate these concepts are presented and discussed.

  4. Four-Dimensional Graded Consciousness.

    Science.gov (United States)

    Jonkisz, Jakub; Wierzchoń, Michał; Binder, Marek

    2017-01-01

    Both the multidimensional phenomenon and the polysemous notion of consciousness continue to prove resistant to consistent measurement and unambiguous definition. This is hardly surprising, given that there is no agreement even as regards the most fundamental issues they involve. One of the basic disagreements present in the continuing debate about consciousness pertains to its gradational nature. The general aim of this article is to show how consciousness might be graded and multidimensional at the same time. We therefore focus on the question of what it is, exactly, that is or could be graded in cases of consciousness, and how we can measure it. Ultimately, four different gradable aspects of consciousness will be described: quality, abstractness, complexity and usefulness, which belong to four different dimensions, these being understood, respectively, as phenomenal, semantic, physiological, and functional. Consequently, consciousness may be said to vary with respect to phenomenal quality, semantic abstraction, physiological complexity, and functional usefulness. It is hoped that such a four-dimensional approach will help to clarify and justify claims about the hierarchical nature of consciousness. The approach also proves explanatorily advantageous, as it enables us not only to draw attention to certain new and important differences in respect of subjective measures of awareness and to justify how a given creature may be ranked higher in one dimension of consciousness and lower in terms of another, but also allows for innovative explanations of a variety of well-known phenomena (amongst these, the interpretations of blindsight and locked-in syndrome will be briefly outlined here). Moreover, a 4D framework makes possible many predictions and hypotheses that may be experimentally tested (We point out a few such possibilities pertaining to interdimensional dependencies).

  5. Two dimensional fermions in four dimensional YM

    CERN Document Server

    Narayanan, R

    2009-01-01

    Dirac fermions in the fundamental representation of SU(N) live on a two dimensional torus flatly embedded in $R^4$. They interact with a four dimensional SU(N) Yang Mills vector potential preserving a global chiral symmetry at finite $N$. As the size of the torus in units of $\\frac{1}{\\Lambda_{SU(N)}}$ is varied from small to large, the chiral symmetry gets spontaneously broken in the infinite $N$ limit.

  6. String Breaking in Four Dimensional Lattice QCD

    CERN Document Server

    Duncan, A; Thacker, H

    2001-01-01

    Virtual quark pair screening leads to breaking of the string between fundamental representation quarks in QCD. For unquenched four dimensional lattice QCD, this (so far elusive) phenomenon is studied using the recently developed truncated determinant algorithm (TDA). The dynamical configurations were generated on an Athlon 650 MHz PC. Quark eigenmodes up to 420 MeV are included exactly in these TDA studies performed at low quark mass on large coarse (but O($a^2$) improved) lattices. A study of Wilson line correlators in Coulomb gauge extracted from an ensemble of 1000 two-flavor dynamical configurations reveals evidence for flattening of the string tension at distances R $\\geq$ approximately 1 fm.

  7. Purely Four-dimensional Viable Anomaly Mediation

    CERN Document Server

    Harnik, R; Pierce, A T; Harnik, Roni; Murayama, Hitoshi; Pierce, Aaron

    2002-01-01

    Anomaly mediation of supersymmetry breaking solves the supersymmetric flavor problem thanks to its ultraviolet-insensitivity. However, it suffers from two problems: sleptons have negative masses-squared, and there are likely bulk moduli that spoil the framework. Here, we present the first fully ultraviolet-insensitive model of anomaly mediation with positive slepton masses-squared in a purely four-dimensional framework. Our model is based on the additional D-term contributions to the sparticle masses of Arkani-Hamed, Kaplan, HM, and Nomura, and the conformal sequestering mechanism of Luty and Sundrum.

  8. Four dimensional non-critical strings

    CERN Document Server

    Ferrari, F

    2002-01-01

    This is a set of lectures on the gauge/string duality and non-critical strings, with a particular emphasis on the discretized, or matrix model, approach. After a general discussion of various points of view, I describe the recent generalization to four dimensional non-critical (or five dimensional critical) string theories of the matrix model approach. This yields fully non-perturbative and explicit definition of string theories with eight (or more) supercharges that are related to four dimensional CFTs and their relevant deformations. The space-time as well as world-sheet dimensions of the supersymmetry preserving world-sheet couplings are obtained. Exact formulas for the central charge of the space-time supersymmetry algebra as a function of these couplings are calculated. They include infinite series of string perturbative contributions as well as all the non-perturbative effects. An important insight on the gauge theory side is that instantons yield a non-trivial 1/N expansion at strong coupling, and gene...

  9. N=3 four dimensional field theories

    CERN Document Server

    García-Etxebarria, Iñaki

    2015-01-01

    We introduce a class of four dimensional field theories constructed by quotienting ordinary $\\mathcal{N}=4$ $U(N)$ SYM by particular combinations of R-symmetry and $SL(2,\\mathbb{Z})$ automorphisms. These theories appear naturally on the worldvolume of D3 branes probing terminal singularities in F-theory, where they can be thought of as non-perturbative generalizations of the O3 plane. We focus on cases preserving only 12 supercharges, where the quotient gives rise to theories with coupling fixed at a value of order one. These constructions posses an unconventional large $N$ limit described by a non-trivial F-theory fibration with base $AdS_5\\times (S^5/\\mathbb{Z}_k)$. Upon reduction on a circle the $\\mathcal{N}=3$ theories flow to well-known $\\mathcal{N}=6$ ABJM theories.

  10. Four-dimensional unsubtraction with massive particles

    CERN Document Server

    Sborlini, German F R; Rodrigo, German

    2016-01-01

    We extend the four-dimensional unsubtraction method, which is based on the loop-tree duality (LTD), to deal with processes involving heavy particles. The method allows to perform the summation over degenerate IR configurations directly at integrand level in such a way that NLO corrections can be implemented directly in four space-time dimensions. We define a general momentum mapping between the real and virtual kinematics that accounts properly for the quasi-collinear configurations, and leads to an smooth massless limit. We illustrate the method first with an scalar toy example, and then analyse the case of the decay of a scalar or vector boson into a pair of massive quarks. The results presented in this paper are suitable for the application of the method to any multipartonic process.

  11. Chiral Four-Dimensional Heterotic Covariant Lattices

    CERN Document Server

    Beye, Florian

    2014-01-01

    In the covariant lattice formalism, chiral four-dimensional heterotic string vacua are obtained from certain even self-dual lattices which completely decompose into a left-mover and a right-mover lattice. The main purpose of this work is to classify all right-mover lattices that can appear in such a chiral model, and to study the corresponding left-mover lattices using the theory of lattice genera. In particular, the Smith-Minkowski-Siegel mass formula is employed to calculate a lower bound on the number of left-mover lattices. Also, the known relationship between asymmetric orbifolds and covariant lattices is considered in the context of our classification.

  12. Four-dimensional coherent electronic Raman spectroscopy

    Science.gov (United States)

    Harel, Elad

    2017-04-01

    The correlations between different quantum-mechanical degrees of freedom of molecular species dictate their chemical and physical properties. Generally, these correlations are reflected in the optical response of the system but in low-order or low-dimensionality measurement the signals are highly averaged. Here, we describe a novel four-dimensional coherent spectroscopic method that directly correlates within and between the manifold of electronic and vibrational states. The optical response theory is developed in terms of both resonant and non-resonant field-matter interactions. Using resonance to select coherences on specific electronic states creates opportunities to directly distinguish coherent dynamics on the ground and electronically excited potentials. Critically, this method is free from lower-order signals that have plagued other electronically non-resonant vibrational spectroscopies. The theory presented here compliments recent work on the experimental demonstration of the 4D spectroscopic method described. We highlight specific means by which non-trivial effects such as anharmonicity (diagonal and off-diagonal), mode-specific vibronic coupling, and curvature of the excited states manifest in different projections of the 4D spectrum.

  13. Four-Dimensional Spin Foam Perturbation Theory

    Directory of Open Access Journals (Sweden)

    João Faria Martins

    2011-10-01

    Full Text Available We define a four-dimensional spin-foam perturbation theory for the BF-theory with a B∧B potential term defined for a compact semi-simple Lie group G on a compact orientable 4-manifold M. This is done by using the formal spin foam perturbative series coming from the spin-foam generating functional. We then regularize the terms in the perturbative series by passing to the category of representations of the quantum group U_q(g where g is the Lie algebra of G and q is a root of unity. The Chain-Mail formalism can be used to calculate the perturbative terms when the vector space of intertwiners Λ⊗Λ→A, where A is the adjoint representation of g, is 1-dimensional for each irrep Λ. We calculate the partition function Z in the dilute-gas limit for a special class of triangulations of restricted local complexity, which we conjecture to exist on any 4-manifold M. We prove that the first-order perturbative contribution vanishes for finite triangulations, so that we define a dilute-gas limit by using the second-order contribution. We show that Z is an analytic continuation of the Crane-Yetter partition function. Furthermore, we relate Z to the partition function for the F∧F theory.

  14. General flat four-dimensional world pictures and clock systems

    Science.gov (United States)

    Hsu, J. P.; Underwood, J. A.

    1978-01-01

    We explore the mathematical structure and the physical implications of a general four-dimensional symmetry framework which is consistent with the Poincare-Einstein principle of relativity for physical laws and with experiments. In particular, we discuss a four-dimensional framework in which all observers in different frames use one and the same grid of clocks. The general framework includes special relativity and a recently proposed new four-dimensional symmetry with a nonuniversal light speed as two special simple cases. The connection between the properties of light propagation and the convention concerning clock systems is also discussed, and is seen to be nonunique within the four-dimensional framework.

  15. Successive superalgebraic truncations from the four-dimensional maximal supergravity

    CERN Document Server

    Kim, C H; Kim, K Y; Kim, Y; Kim, Chang Ho; Park, Young Jai; Kim, Kee Yong; Kim, Yongduk

    1994-01-01

    We study the four-dimensional {\\it N}=8 maximal supergravity in the context of Lie superalgebra SU(8/1). All possible successive superalgebraic truncations from four-dimensional {\\it N}=8 theory to {\\it N}=7, 6, \\cdots, 1 supergravity theories are systematically realized as sub-superalgebra chains of SU(8/1) by using the Kac-Dynkin weight techniques.

  16. Inverse Operation of Four-dimensional Vector Matrix

    Directory of Open Access Journals (Sweden)

    H J Bao

    2011-08-01

    Full Text Available This is a new series of study to define and prove multidimensional vector matrix mathematics, which includes four-dimensional vector matrix determinant, four-dimensional vector matrix inverse and related properties. There are innovative concepts of multi-dimensional vector matrix mathematics created by authors with numerous applications in engineering, math, video conferencing, 3D TV, and other fields.

  17. On the four-dimensional formulation of dimensionally regulated amplitudes

    Energy Technology Data Exchange (ETDEWEB)

    Fazio, A.R. [Universidad Nacional de Colombia, Departamento de Fisica, Bogota (Colombia); Mastrolia, P. [Universita di Padova, Dipartimento di Fisica e Astronomia, Padua (Italy); Max-Planck-Institut fuer Physik, Munich (Germany); INFN, Padova (Italy); Mirabella, E. [Max-Planck-Institut fuer Physik, Munich (Germany); Torres Bobadilla, W.J. [Universidad Nacional de Colombia, Departamento de Fisica, Bogota (Colombia); Universita di Padova, Dipartimento di Fisica e Astronomia, Padua (Italy); INFN, Padova (Italy)

    2014-12-01

    Elaborating on the four-dimensional helicity scheme, we propose a pure four-dimensional formulation (FDF) of the d-dimensional regularization of one-loop scattering amplitudes. In our formulation particles propagating inside the loop are represented by massive internal states regulating the divergences. The latter obey Feynman rules containing multiplicative selection rules which automatically account for the effects of the extra-dimensional regulating terms of the amplitude. We present explicit representations of the polarization and helicity states of the four-dimensional particles propagating in the loop. They allow for a complete, four-dimensional, unitarity-based construction of d-dimensional amplitudes. Generalized unitarity within the FDF does not require any higher-dimensional extension of the Clifford and the spinor algebra. Finally we show how the FDF allows for the recursive construction of d-dimensional one-loop integrands, generalizing the four-dimensional open-loop approach. (orig.)

  18. Interobserver agreement in detailed prenatal diagnosis of congenital heart disease by telemedicine using four-dimensional ultrasound with spatiotemporal image correlation

    NARCIS (Netherlands)

    Adriaanse, B.M.; Tromp, C.H.; Simpson, J.M.; Mieghem, T. van; Kist, W.J.; Kuik, D.J.; Oepkes, D.; Vugt, J.M. van; Haak, M.C.

    2012-01-01

    OBJECTIVE: To evaluate the clinical accuracy of four-dimensional (4D) echocardiography in the detailed prenatal diagnosis of congenital heart disease (CHD) in a telemedicine setting. METHODS: Ten second-trimester spatiotemporal image correlation (STIC) volumes were sent to three observers in differe

  19. Anisotropic Four-Dimensional NS-NS String Cosmology

    CERN Document Server

    Chen, C M; Mak, M K; Chen, Chiang-Mei

    2001-01-01

    An anisotropic (Bianchi type I) cosmology is considered in the four-dimensional NS-NS sector of low-energy effective string theory coupled to a dilaton and an axion-like $H$-field within a de Sitter-Einstein frame background. The time evolution of this Universe is discussed in both the Einstein and string frames.

  20. Teaching Life Cycles: The Four-Dimensional Organism.

    Science.gov (United States)

    Harper, G. H.

    1987-01-01

    Argues that life cycles and the concept of the four-dimensional organism should be the most important idea in teaching high school biology in the United Kingdom. Presents a set of concepts and terms with a view to improving the perceived confusion in present teaching situations. (TW)

  1. Gravitational and Axionic Backgrounds for Four-dimensional Superstrings

    CERN Document Server

    Lüst, Dieter

    1993-01-01

    We construct new four-dimensional superstring vacua with extended superconformal symmetries. A non-trivial dilaton background implies the existence of Abelian killing symmetries. These are used to construct dual equivalent backgrounds in a way preserving the N=2 superconformal invariance.

  2. A novel four-dimensional autonomous hyperchaotic system

    Institute of Scientific and Technical Information of China (English)

    Liu Chong-Xin; Liu Ling

    2009-01-01

    A novel four-dimensional autonomous hyperchaotic system is reported in this paper. Some basic dynamical properties of the new hyperchaotic system are investigated in detail by means of a continuous spectrum, Lyapunov hyperchaotic system are proved by not only performing numerical simulation and brief theoretical analysis but also by conducting an electronic circuit experiment.

  3. The scalar curvature problem on the four dimensional half sphere

    CERN Document Server

    Ben-Ayed, M; El-Mehdi, K

    2003-01-01

    In this paper, we consider the problem of prescribing the scalar curvature under minimal boundary conditions on the standard four dimensional half sphere. We provide an Euler-Hopf type criterion for a given function to be a scalar curvature for some metric conformal to the standard one. Our proof involves the study of critical points at infinity of the associated variational problem.

  4. Manual control displays for a four-dimensional landing approach

    Science.gov (United States)

    Silverthorn, J. T.; Swaim, R. L.

    1975-01-01

    Six instrument rated pilots flew a STOL fixed base simulator to study the effectiveness of three displays for a four dimensional approach. The three examined displays were a digital readout of forward position error, a digital speed command, and an analog display showing forward position error and error prediction. A flight director was used in all conditions. All test runs were for a typical four dimensional approach in moderate turbulence that included a change in commanded ground speed, a change in flight path angle, and two standard rate sixty degree turns. Use of the digital forward position error display resulted in large overshoot in the forward position error. Some type of lead (rate or prediction information) was shown to be needed. The best overall performance was obtained using the speed command display. It was demonstrated that curved approaches can be flown with relative ease.

  5. IDENTIFICATION OF ARCHITECTURAL FUNCTIONS IN A FOUR-DIMENSIONAL SPACE

    Directory of Open Access Journals (Sweden)

    Firza Utama Sjarifudin

    2012-05-01

    Full Text Available This research has explored the possibilities and concept of architectural space in a virtual environment. The virtual environment exists as a different concept, and challenges the constraints of the physical world. One of the possibilities in a virtual environment is that it is able to extend the spatial dimension higher than the physical three-dimension. To take the advantage of this possibility, this research has applied some geometrical four-dimensional (4D methods to define virtual architectural space. The spatial characteristics of 4D space is established by analyzing the four-dimensional structure that can be comprehended by human participant for its spatial quality, and by developing a system to control the fourth axis of movement. Multiple three-dimensional spaces that fluidly change their volume have been defined as one of the possibilities of virtual architectural space concept in order to enrich our understanding of virtual spatial experience.

  6. Aspects of the Supersymmetry Algebra in Four Dimensional Euclidean Space

    CERN Document Server

    McKeon, D G C

    1998-01-01

    The simplest supersymmetry (SUSY) algebra in four dimensional Euclidean space ($4dE$) has been shown to closely resemble the $N = 2$ SUSY algebra in four dimensional Minkowski space ($4dM$). The structure of the former algebra is examined in greater detail in this paper. We first present its Clifford algebra structure. This algebra shows that the momentum Casimir invariant of physical states has an upper bound which is fixed by the central charges. Secondly, we use reduction of the $N = 1$ SUSY algebra in six dimensional Minkowski space ($6dM$) to $4dE$; this reproduces our SUSY algebra in $4dE$. Moreover, this same reduction of supersymmetric Yang-Mills theory (SSYM) in $6dM$ reproduces Zumino's SSYM in $4dE$. We demonstrate how this dimensional reduction can be used to introduce additional generators into the SUSY algebra in $4dE$.

  7. Finding four dimensional symplectic maps with reduced chaos: Preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Weishi Wan; Cary, J.R.; Shasharina, S.G.

    1998-06-01

    A method for finding integrable four-dimensional symplectic maps is outlined. The method relies on solving for parameter values at which the linear stability factors of the fixed points of the map have the values corresponding to integrability. This method is applied to accelerator lattices in order to increase dynamic aperture. Results show a increase of the dynamic aperture after correction, which implies the validity of the method.

  8. Integrable four-dimensional symplectic maps of standard type

    CERN Document Server

    McLachlan, R I

    1993-01-01

    We search for rational, four-dimensional maps of standard type (x_{n+1} - 2x_n + x_{n-1} = eps f(x,eps)) possessing one or two polynomial integrals. There are no non-trivial maps corresponding to cubic oscillators, but we find a four-parameter family of such maps corresponding to quartic oscillators. This seems to be the only such example.

  9. Stress echocardiography

    NARCIS (Netherlands)

    A. Salustri (Alessandro)

    1993-01-01

    textabstractIn the studies reported in this thesis, stress echocardiography (either with exercise or with pharmacological agents) and myocardial perfusion scintigraphy have been performed in different groups of patients and in different clinical conditions. Some practical aspects on the protocols of

  10. Stress echocardiography

    NARCIS (Netherlands)

    A. Salustri (Alessandro)

    1993-01-01

    textabstractIn the studies reported in this thesis, stress echocardiography (either with exercise or with pharmacological agents) and myocardial perfusion scintigraphy have been performed in different groups of patients and in different clinical conditions. Some practical aspects on the protocols

  11. Temporal Parameter Optimization in Four-Dimensional Flash Trajectory Imaging

    Institute of Scientific and Technical Information of China (English)

    WANG Xin-Wei; ZHOU Yan; FAN Song-Tao; LIU Yu-Liang

    2011-01-01

    In four-dimensional fiash trajectory imaging, temporal parameters include time delay, laser pulse width, gate time, pulse pair repetition frequency and the frame rate of CCD, which directly impact on the acquisition of target trajectories over time. We propose a method of optimizing the temporal parameters of flash trajectory imaging. All the temporal parameters can be estimated by the spatial parameters of the volumes of interest, target scale and velocity, and target sample number. The formulae for optimizing temporal parameters are derived, and the method is demonstrated in an experiment with a ball oscillating as a pendulum.%In four-dimensional flash trajectory imaging,temporal parameters include time delay,laser pulse width,gate time,pulse pair repetition frequency and the frame rate of CCD,which directly impact on the acquisition of target trajectories over time.We propose a method of optimizing the temporal parameters of flash trajectory imaging.All the temporal parameters can be estimated by the spatial parameters of the volumes of interest,target scale and velocity,and target sample number.The formulae for optimizing temporal parameters are derived,and the method is demonstrated in an experiment with a ball oscillating as a pendulum.Four-dimensional flash trajectory imaging (FTI)based on time-delay-modulated range-gated viewing can directly image the trajectories of moving objects with backgrounds filtered and deduce target 3D positions over time,[1] which has potentials in astronomy,remote sensing and biomedical applications.[2 4] Temporal parameters are crucial for FTI.An unreasonable setting of temporal parameters will lead to failure in obtaining target trajectories.However,in the previous work,[1] the optimization of temporal parameters has not been discussed in detail.Therefore,in this Letter we give a method of estimating the temporal parameters of FTI.

  12. Local bifurcation analysis of a four-dimensional hyperchaotic system

    Institute of Scientific and Technical Information of China (English)

    Wu Wen-Juan; Chen Zeng-Qiang; Yuan Zhu-Zhi

    2008-01-01

    Local bifurcation phenomena in a four-dimensional continuous hyperchaotic system, which has rich and complex dynamical behaviours, are analysed. The local bifurcations of the system are investigated by utilizing the bifurcation theory and the centre manifold theorem, and thus the conditions of the existence of pitchfork bifurcation and Hopf bifurcation are derived in detail. Numerical simulations are presented to verify the theoretical analysis, and they show some interesting dynamics, including stable periodic orbits emerging from the new fixed points generated by pitchfork bifurcation, coexistence of a stable limit cycle and a chaotic attractor, as well as chaos within quite a wide parameter region.

  13. Four-dimensional optical manipulation of colloidal particles

    DEFF Research Database (Denmark)

    Rodrigo, P.J.; Daria, V.R.; Glückstad, J.

    2005-01-01

    We transform a TEM00 laser mode into multiple counterpropagating optical traps to achieve four-dimensional simultaneous manipulation of multiple particles. Efficient synthesis and dynamic control of the counterpropagating-beam traps is carried out via the generalized phase contrast method......, and a spatial polarization-encoding scheme. Our experiments genuinely demonstrate real-time, interactive particle-position control for forming arbitrary volumetric constellations and complex three-dimensional trajectories of multiple particles. This opens up doors for cross-disciplinary cutting-edge research...

  14. Four-Dimensional Gallant-Lambert-Vanstone Scalar Multiplication

    CERN Document Server

    Birkner, Peter

    2011-01-01

    The GLV method of Gallant, Lambert and Vanstone (CRYPTO 2001) computes any multiple $kP$ of a point $P$ of prime order $n$ lying on an elliptic curve with a low-degree endomorphism $\\Phi$ (called GLV curve) over $\\mathbb{F}_p$ as \\[kP = k_1P + k_2\\Phi(P), \\quad\\text{with} \\max\\{|k_1|,|k_2|\\}\\leq C\\sqrt n] for some explicit constant $C>0$. Recently, Galbraith, Lin and Scott (EUROCRYPT 2009) extended this method to all curves over $\\mathbb{F}_{p^2}$ which are twists of curves defined over $\\mathbb{F}_p$. These are examples of two-dimensional decompositions (with two new scalars), and the GLS approach shows that for curves with many automorphisms (cubic and quartic twists) one can achieve a four-dimensional decomposition as well. We show in this work how to merge the two approaches in order to get, for twists of any GLV curve over $\\mathbb{F}_{p^2}$, a four-dimensional decomposition together with fast endomorphisms $\\Phi, \\Psi$ over $\\mathbb{F}_{p^2}$ acting on the group generated by a point $P$ of prime order $...

  15. Four-dimensional black holes in Einsteinian cubic gravity

    Science.gov (United States)

    Bueno, Pablo; Cano, Pablo A.

    2016-12-01

    We construct static and spherically symmetric generalizations of the Schwarzschild- and Reissner-Nordström-(anti-)de Sitter [RN-(A)dS] black-hole solutions in four-dimensional Einsteinian cubic gravity (ECG). The solutions are characterized by a single function which satisfies a nonlinear second-order differential equation. Interestingly, we are able to compute independently the Hawking temperature T , the Wald entropy S and the Abbott-Deser mass M of the solutions analytically as functions of the horizon radius and the ECG coupling constant λ . Using these we show that the first law of black-hole mechanics is exactly satisfied. Some of the solutions have positive specific heat, which makes them thermodynamically stable, even in the uncharged and asymptotically flat case. Further, we claim that, up to cubic order in curvature, ECG is the most general four-dimensional theory of gravity which allows for nontrivial generalizations of Schwarzschild- and RN-(A)dS characterized by a single function which reduce to the usual Einstein gravity solutions when the corresponding higher-order couplings are set to zero.

  16. Platonic solids generate their four-dimensional analogues

    CERN Document Server

    Dechant, Pierre-Philippe

    2013-01-01

    In this paper, we show how regular convex 4-polytopes - the analogues of the Platonic solids in four dimensions - can be constructed from three-dimensional considerations concerning the Platonic solids alone. Via the Cartan-Dieudonne theorem, the reflective symmetries of the Platonic solids generate rotations. In a Clifford algebra framework, the space of spinors generating such three-dimensional rotations has a natural four-dimensional Euclidean structure. The spinors arising from the Platonic Solids can thus in turn be interpreted as vertices in four-dimensional space, giving a simple construction of the 4D polytopes 16-cell, 24-cell, the F_4 root system and the 600-cell. In particular, these polytopes have `mysterious' symmetries, that are almost trivial when seen from the three-dimensional spinorial point of view. In fact, all these induced polytopes are also known to be root systems and thus generate rank-4 Coxeter groups, which can be shown to be a general property of the spinor construction. These cons...

  17. Four-dimensional BPS-spectra via M-theory

    CERN Document Server

    Henningson, M

    1998-01-01

    We consider the realization of four-dimensional theories with N = 2 supersymmetry as M-theory configurations including a five-brane. Our emphasis is on the spectrum of massive states, that are realized as two-branes ending on the five-brane. We start with a determination of the supersymmetries that are left unbroken by the background metric and five-brane. We then show how the central charge of the N = 2 algebra arises from the central charge associated with the M-theory two-brane. This determines the condition for a two-brane configuration to be BPS-saturated in the four-dimensional sense. By imposing certain conditions on the moduli, we can give concrete examples of such two-branes. This leads us to conjecture that vectormultiplet and hypermultiplet BPS-saturated states correspond to two-branes with the topology of a cylinder and a disc respectively. We also discuss the phenomenon of marginal stability of BPS-saturated states.

  18. Decomposable medium conditions in four-dimensional representation

    CERN Document Server

    Lindell, Ismo V; Favaro, Alberto

    2011-01-01

    The well-known TE/TM decomposition of time-harmonic electromagnetic fields in uniaxial anisotropic media is generalized in terms of four-dimensional differential-form formalism by requiring that the field two-form satisfies an orthogonality condition with respect to two given bivectors. Conditions for the electromagnetic medium in which such a decomposition is possible are derived and found to define three subclasses of media. It is shown that the previously known classes of generalized Q-media and generalized P-media are particular cases of the proposed decomposable media (DCM) associated to a quadratic equation for the medium dyadic. As a novel solution, another class of special decomposable media (SDCM) is defined by a linear dyadic equation. The paper further discusses the properties of medium dyadics and plane-wave propagation in all the identified cases of DCM and SDCM.

  19. Four-dimensional black holes in Einsteinian cubic gravity

    CERN Document Server

    Bueno, Pablo

    2016-01-01

    We construct static and spherically symmetric generalizations of the Schwarzschild- and Reissner-Nordstr\\"om-(Anti) de Sitter (RN-(A)dS) black-hole solutions in four-dimensional Einsteinian cubic gravity (ECG). The solutions are determined by a single blackening factor which satisfies a non-linear second-order differential equation. Interestingly, we are able to compute independently the Hawking temperature $T$, the Wald entropy $\\mathsf{S}$ and the Abbott-Deser mass $M$ of the solutions analytically as functions of the horizon radius and the ECG coupling constant $\\lambda$. Using these we show that the first law of black-hole mechanics is exactly satisfied. Some of the solutions have positive specific heat, which makes them thermodynamically stable, even in the uncharged and asymptotically flat case.

  20. The effective action in four-dimensional CDT

    CERN Document Server

    Gizbert-Studnicki, Jakub

    2015-01-01

    We present recent results concerning the measurement and analysis of the effective action in four-dimensional Causal Dynamical Triangulations. The action describes quantum fluctuations of the spatial volume of the CDT universe (or alternatively the scale factor) after integrating out other degrees of freedom. We use the covariance of volume fluctuations to measure and parametrize the effective action inside the de Sitter phase, also called the C phase. We show that the action is consistent with a simple discretization of the minisuperspace action (with a reversed overall sign). We discuss possible subleading corrections and show how to construct a more complicated effective action comprising both integer and half-integer discrete proper time layers. We introduce a new method of the effective action measurement based on the transfer matrix. We show that the results of the new method are fully consistent with the covariance matrix method inside the de Sitter phase. We use the new method to measure the effective...

  1. An explicit four-dimensional variational data assimilation method

    Institute of Scientific and Technical Information of China (English)

    QIU ChongJian; ZHANG Lei; SHAO AiMei

    2007-01-01

    A new data assimilation method called the explicit four-dimensional variational (4DVAR) method is proposed. In this method, the singular value decomposition (SVD) is used to construct the orthogonal basis vectors from a forecast ensemble in a 4D space. The basis vectors represent not only the spatial structure of the analysis variables but also the temporal evolution. After the analysis variables are expressed by a truncated expansion of the basis vectors in the 4D space, the control variables in the cost function appear explicitly, so that the adjoint model, which is used to derive the gradient of cost function with respect to the control variables, is no longer needed. The new technique significantly simplifies the data assimilation process. The advantage of the proposed method is demonstrated by several experiments using a shallow water numerical model and the results are compared with those of the conventional 4DVAR. It is shown that when the observation points are very dense, the conventional 4DVAR is better than the proposed method. However, when the observation points are sparse, the proposed method performs better. The sensitivity of the proposed method with respect to errors in the observations and the numerical model is lower than that of the conventional method.

  2. An explicit four-dimensional variational data assimilation method

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new data assimilation method called the explicit four-dimensional variational (4DVAR) method is proposed. In this method, the singular value decomposition (SVD) is used to construct the orthogonal basis vectors from a forecast ensemble in a 4D space. The basis vectors represent not only the spatial structure of the analysis variables but also the temporal evolution. After the analysis variables are ex-pressed by a truncated expansion of the basis vectors in the 4D space, the control variables in the cost function appear explicitly, so that the adjoint model, which is used to derive the gradient of cost func-tion with respect to the control variables, is no longer needed. The new technique significantly simpli-fies the data assimilation process. The advantage of the proposed method is demonstrated by several experiments using a shallow water numerical model and the results are compared with those of the conventional 4DVAR. It is shown that when the observation points are very dense, the conventional 4DVAR is better than the proposed method. However, when the observation points are sparse, the proposed method performs better. The sensitivity of the proposed method with respect to errors in the observations and the numerical model is lower than that of the conventional method.

  3. The connection between polarization calculus and four-dimensional rotations

    CERN Document Server

    Karlsson, Magnus

    2013-01-01

    We review the well-known polarization optics matrix methods, i.e., Jones and Stokes-Mueller calculus, and show how they can be formulated in terms of four-dimensional (4d) rotations of the four independent electromagnetic field quadratures. Since 4d rotations is a richer description than the conventional Jones and Stokes-Mueller calculi, having six rather than four degrees of freedom (DOF), we propose an extension of those calculi to handle all six DOF. For the Stokes-Mueller analysis, this leads to a novel and potentially useful extension that accounts for the absolute phase of the optical field, and which can be valuable in the areas where the optical phase is of interest, e.g. interferometry or coherent communications. As examples of the usefulness we use the formalism to explain the Pancharatnam phase by parallel transport, and shows its connection with the Berry phase. In addition we show that the two extra DOF in the 4d description represents unphysical transformations, forbidden for propagating photons...

  4. Four-dimensional unsubtraction from the loop-tree duality

    CERN Document Server

    Sborlini, German F R; Hernandez-Pinto, Roger; Rodrigo, German

    2016-01-01

    We present a new algorithm to construct a purely four dimensional representation of higher-order perturbative corrections to physical cross-sections at next-to-leading order (NLO). The algorithm is based on the loop-tree duality (LTD), and it is implemented by introducing a suitable mapping between the external and loop momenta of the virtual scattering amplitudes with the external momenta of the real emission corrections. In this way, the sum over degenerate infrared states is performed at the integrand level and the cancellation of infrared divergences occurs locally without introducing subtraction counter-terms to deal with soft and final-state collinear singularities. The dual representation of ultraviolet counter-terms is also discussed in detail, in particular for self-energy contributions. The method is first illustrated with the scalar three-point function, before proceeding with the calculation of the physical cross-section for $\\gamma^* \\to q \\bar{q}(g)$, at its generalisation to multi-leg processes...

  5. Constraints on RG Flow for Four Dimensional Quantum Field Theories

    CERN Document Server

    Jack, I

    2013-01-01

    The response of four dimensional quantum field theories to a Weyl rescaling of the metric in the presence of local couplings and which involve $a$, the coefficient of the Euler density in the energy momentum tensor trace on curved space, is reconsidered. Previous consistency conditions for the anomalous terms, which implicitly define a metric $G$ on the space of couplings and give rise to gradient flow like equations for $a$, are derived taking into account the role of lower dimension operators. The results for infinitesimal Weyl rescaling are integrated to finite rescalings $e^{2\\sigma}$ to a form which involves running couplings $g_\\sigma$ and which interpolates between IR and UV fixed points. The results are also restricted to flat space where they give rise to broken conformal Ward identities. Expressions for the three loop Yukawa $\\beta$-functions for a general scalar/fermion theory are obtained and the three loop contribution to the metric $G$ for this theory are also calculated. These results are used ...

  6. Constraints on RG flow for four dimensional quantum field theories

    Science.gov (United States)

    Jack, I.; Osborn, H.

    2014-06-01

    The response of four dimensional quantum field theories to a Weyl rescaling of the metric in the presence of local couplings and which involve a, the coefficient of the Euler density in the energy momentum tensor trace on curved space, is reconsidered. Previous consistency conditions for the anomalous terms, which implicitly define a metric G on the space of couplings and give rise to gradient flow like equations for a, are derived taking into account the role of lower dimension operators. The results for infinitesimal Weyl rescaling are integrated to finite rescalings e2σ to a form which involves running couplings gσ and which interpolates between IR and UV fixed points. The results are also restricted to flat space where they give rise to broken conformal Ward identities. Expressions for the three loop Yukawa β-functions for a general scalar/fermion theory are obtained and the three loop contribution to the metric G for this theory is also calculated. These results are used to check the gradient flow equations to higher order than previously. It is shown that these are only valid when β→B, a modified β-function, and that the equations provide strong constraints on the detailed form of the three loop Yukawa β-function. N=1 supersymmetric Wess-Zumino theories are also considered as a special case. It is shown that the metric for the complex couplings in such theories may be restricted to a hermitian form.

  7. Four-dimensional unsubtraction from the loop-tree duality

    Science.gov (United States)

    Sborlini, Germán F. R.; Driencourt-Mangin, Félix; Hernández-Pinto, Roger J.; Rodrigo, Germán

    2016-08-01

    We present a new algorithm to construct a purely four dimensional representation of higher-order perturbative corrections to physical cross-sections at next-to-leading order (NLO). The algorithm is based on the loop-tree duality (LTD), and it is implemented by introducing a suitable mapping between the external and loop momenta of the virtual scattering amplitudes, and the external momenta of the real emission corrections. In this way, the sum over degenerate infrared states is performed at integrand level and the cancellation of infrared divergences occurs locally without introducing subtraction counter-terms to deal with soft and final-state collinear singularities. The dual representation of ultraviolet counter-terms is also discussed in detail, in particular for self-energy contributions. The method is first illustrated with the scalar three-point function, before proceeding with the calculation of the physical cross-section for {γ}^{ast}to qoverline{q}(g) , and its generalisation to multi-leg processes. The extension to next-to-next-to-leading order (NNLO) is briefly commented.

  8. Intracardiac echocardiography.

    Science.gov (United States)

    Bruce, C J; Friedman, P A

    2002-10-01

    This article describes currently available intracardiac ultrasound (ICE) technology contrasting it with intravascular ultrasound (IVUS) highlighting their differences. Clinical applications in the electrophysiologic and cardiac catheterization laboratory are discussed and current limitations addressed. Intracardiac echocardiography (ICE) is possible because lower frequency transducers (in contrast to higher frequency IVUS devices) have been miniaturized and mounted onto catheters capable of percutaneous insertion into the heart. These lower frequency transducers are capable of enhanced tissue penetration, permitting high-resolution 2D "whole heart" imaging. Also, with the introduction of the newest phased array transducer, Doppler hemodynamic data in addition to high resolution imaging can also be obtained. ICE facilitates electrophysiologic procedures by guiding transseptal catheterization, enabling endocardial anatomy visualization and targeting of arrhythmogenic substrate, ensuring optimal ablation electrode/tissue contact and promptly diagnosing procedural complications. Promising non-electrophysiologic applications include guidance of percutaneous closure of septal defects, percutaneous mitral balloon valvuloplasty and complex cardiac biopsy. Current limitations include monoplanar imaging, narrow field of view, and relatively large size of the catheter. Intra-cardiac imaging is now a clinical tool and has the potential to play an important role in diagnostic and therapeutic interventional procedures. Further refinement and miniaturization of these transducers, through continued technological progress, will make way for primary operator controlled, integrated ultrasound-guided interventional devices.

  9. EXISTENCE OF PERIODIC SOLUTIONS TO A PERTURBED FOUR-DIMENSIONAL SYSTEM

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Consider a k multiple closed orbit on an invariant surface of a four dimensional system, after a suitable perturbation, the closed orbit can generate periodic orbits and double-period orbits. Using bifurcation methods and techniques, sufficient conditions for the existence of periodic solutions to the perturbed four dimensional system are obtained, and the period-doubling bifurcations is discussed.

  10. A Note on Four-Dimensional Symmetry Algebras and Fourth-Order Ordinary Differential Equations

    Directory of Open Access Journals (Sweden)

    A. Fatima

    2013-01-01

    Full Text Available We provide a supplementation of the results on the canonical forms for scalar fourth-order ordinary differential equations (ODEs which admit four-dimensional Lie algebras obtained recently. Together with these new canonical forms, a complete list of scalar fourth-order ODEs that admit four-dimensional Lie algebras is available.

  11. American Society of Echocardiography

    Science.gov (United States)

    American Society of Echocardiography Join Ase Member Portal Log In Membership Member Portal Log In Join ASE Renew Benefits Rates FASE – Fellow of the American Society of Echocardiography Member Referral Program FAQs Initiatives Advocacy ...

  12. Four-dimensional computed tomography angiographic evaluation of cranial dural arteriovenous fistula before and after embolization

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Bing, E-mail: bing.tian@hotmail.com; Xu, Bing, E-mail: aishanli0102@126.com; Lu, Jianping, E-mail: tianbing2003@163.com; Liu, Qi, E-mail: liuqimd@126.com; Wang, Li, E-mail: wangli_changhai@163.com; Wang, Minjie, E-mail: cjr.wangminjie@vip.163.com

    2015-06-15

    Highlights: • 4D CTA showed excellent agreement with DSA with regard to identification of feeding arteries and drainage veins. • The most important finding was 4D CTA in determining the impact of DAVF treatment with transarterial embolization. • 4D CTA provides images similar to those obtained with DSA both before and after treatment. - Abstract: Purpose: This study aimed to evaluate the usefulness of four-dimensional CTA before and after embolization treatment with ONYX-18 in eleven patients with cranial dural arteriovenous fistulas, and to compare the results with those of the reference standard DSA. Patients and Methods: Eleven patients with cranial dural arteriovenous fistulas detected on DSA underwent transarterial embolization with ONYX-18. Four-dimensional CTA was performed an average of 2 days before and 4 days after DSA. Four-dimensional CTA and DSA images were reviewed by two neuroradiologists for identification of feeding arteries and drainage veins and for determining treatment effects. Interobserver and intermodality agreement between four-dimensional CTA and DSA were assessed. Results: Forty-two feeding arteries were identified for 14 fistulas in the 11 patients. Of these, 36 (85.71%) were detected on four-dimensional CTA. After transarterial embolization, one patient got partly embolized, and the fistulas in the remaining 10 patients were completely occluded. The interobserver agreement for four-dimensional CTA and intermodality agreement between four-dimensional CTA and DSA were excellent (κ = 1) for shunt location, identification of drainage veins, and fistula occlusion after treatment. Conclusion: Four-dimensional CTA images are highly accurate when compared with DSA images both before and after transarterial embolization treatment. Four-dimensional CTA can be used for diagnosis as well as follow-up of cranial dural arteriovenous fistulas in clinical settings.

  13. Construction of a Class of Four-Dimensional Piecewise Affine Systems with Homoclinic Orbits

    Science.gov (United States)

    Wu, Tiantian; Yang, Xiao-Song

    2016-06-01

    Based on mathematical analysis, this paper provides a methodology to ensure the existence of homoclinic orbits in a class of four-dimensional piecewise affine systems. In addition, an example is provided to illustrate the effectiveness of the method.

  14. Improving the Horizontal Transport in the Lower Troposphere with Four Dimensional Data Assimilation

    Science.gov (United States)

    The physical processes involved in air quality modeling are governed by dynamically-generated meteorological model fields. This research focuses on reducing the uncertainty in the horizontal transport in the lower troposphere by improving the four dimensional data assimilation (F...

  15. Chaotic behaviour of nonlinear coupled reaction–diffusion system in four-dimensional space

    Indian Academy of Sciences (India)

    Li Zhang; Shutang Liu; Chenglong Yu

    2014-06-01

    In recent years, nonlinear coupled reaction–diffusion (CRD) system has been widely investigated by coupled map lattice method. Previously, nonlinear behaviour was observed dynamically when one or two of the three variables in the discrete system change. In this paper, we consider the chaotic behaviour when three variables change, which is called as four-dimensional chaos. When two parameters in the discrete system are unknown, we first give the existing condition of the chaos in four-dimensional space by the generalized definitions of spatial periodic orbits and spatial chaos. In addition, the chaotic behaviour will vary with the parameters. Then we propose a generalized Lyapunov exponent in four-dimensional space to characterize the different effects of parameters on the chaotic behaviour, which has not been studied in detail. In order to verify the chaotic behaviour of the system and the different effects clearly, we simulate the dynamical behaviour in two- and three-dimensional spaces.

  16. Covariant Four-Dimensional Scattering Equations for the NN- πNNSystem

    Science.gov (United States)

    Phillips, D. R.; Afnan, I. R.

    1996-04-01

    We derive a set of coupled four-dimensional integral equations for theNN-πNNsystem using our modified version of the Taylor method of classification-of-diagrams. These equations are covariant, obey two- and three-body unitarity and contain subtraction terms which eliminate the double-counting present in some previous four-dimensionalNN-πNNequations. The equations are then recast into a from convenient for computation by grouping the subtraction terms together and obtaining a set of two-fragment scattering equations for the amplitudes of interest.

  17. Covariant four-dimensional scattering equations for the NN - {pi}NN system

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, D.R.; Afnan, I.R. [Flinders Univ. of South Australia, Adelaide (Australia)

    1996-04-10

    The authors derive a set of coupled four-dimensional integral equations for the NN - {pi}NN system using their modified version of the Taylor method of classification-of-diagrams. These equations are covariant, obey two- and three-body unitarity and contain subtraction terms which eliminate the double-counting present in some previous four-dimensional NN - {pi}NN equations. The equations are then recast into a form convenient for computation by grouping the subtraction terms together and obtaining a set of two-fragment scattering equations for the amplitudes of interest. 43 refs., 20 figs.

  18. Randers metrics of Berwald type on four-dimensional hypercomplex Lie groups

    Energy Technology Data Exchange (ETDEWEB)

    Moghaddam, H R Salimi [Department of Mathematics, Shahrood University of Technology, Shahrood (Iran, Islamic Republic of)], E-mail: hrsalimi@shahroodut.ac.ir

    2009-03-06

    In the present paper we study Randers metrics of Berwald type on simply connected four-dimensional real Lie groups admitting invariant hypercomplex structure. On these spaces, the Randers metrics arising from invariant hyper-Hermitian metrics are considered. Then we give explicit formulae for computing the flag curvature of these metrics. By this study we construct two four-dimensional Berwald spaces, one of them with a non-negative flag curvature and the other one with a non-positive flag curvature.

  19. Experimental measurement of the four-dimensional coherence function for an undulator x-ray source.

    Science.gov (United States)

    Tran, C Q; Williams, G J; Roberts, A; Flewett, S; Peele, A G; Paterson, D; de Jonge, M D; Nugent, K A

    2007-06-01

    A full measurement of the four-dimensional coherence function from an undulator beam line is reported. The analysis is based on the observation that the data are consistent with a coherence function that is mathematically separable. The effective source size can be altered by changing the width of the exit slit, and the complete coherence function is presented for two settings. We find, to within experimental error, that the four-dimensional complex degree of coherence can be described as a real Gaussian function that depends only on the difference of the spatial coordinates.

  20. A Calogero formulation for four-dimensional black-hole microstates

    Directory of Open Access Journals (Sweden)

    Olaf Lechtenfeld

    2016-02-01

    Full Text Available We extract the leading-order entropy of a four-dimensional extremal black hole in N=2 ungauged supergravity by formulating the CFT1 that is holographically dual to its near-horizon AdS2 geometry, in terms of a rational Calogero model with a known counting formula for the degeneracy of states in its Hilbert space.

  1. M-theory resolution of four-dimensional cosmological singularities via U-duality

    NARCIS (Netherlands)

    Feinstein, A.; Vazquez-Mozo, M.A.

    2000-01-01

    We consider cosmological solutions of string and M-theory compactified to four dimensions by giving a general prescription to construct four-dimensional modular cosmologies with two commuting Killing vectors from vacuum solutions. By lifting these solutions to higher dimensions we analyze the existe

  2. Some Aspects of Four Dimensional Black Hole Solutions in Gauss-Bonnet Extended String Gravity

    OpenAIRE

    Alexeyev, S. O.; Sazhin, M. V.

    1997-01-01

    An internal singularity of a string four-dimensional black hole with second order curvature corrections is discussed. A restriction to a minimal size of a neutral black hole is obtained in the frame of the model considered. Vacuum polarization of the surrounding space-time caused by this minimal-size black hole is also discussed.

  3. The ambiguity-free four-dimensional Lorentz-breaking Chern-Simons action

    Energy Technology Data Exchange (ETDEWEB)

    Brito, F.A. [Departamento de Fisica, Universidade Federal de Campina Grande, Caixa Postal 10071, 58109-970 Campina Grande, Paraiba (Brazil); Nascimento, J.R.; Passos, E. [Departamento de Fisica, Universidade Federal da Paraiba, Caixa Postal 5008, 58051-970 Joao Pessoa, Paraiba (Brazil); Petrov, A.Yu. [Departamento de Fisica, Universidade Federal da Paraiba, Caixa Postal 5008, 58051-970 Joao Pessoa, Paraiba (Brazil)], E-mail: petrov@fisica.ufpb.br

    2008-06-12

    The four-dimensional Lorentz-breaking finite and determined Chern-Simons like action is generated as a one-loop perturbative correction via an appropriate Lorentz-breaking coupling of the gauge field with the spinor field. Unlike the known schemes of calculations, within this scheme this term is found to be regularization independent.

  4. Effect of four-dimensional variational data assimilation in case of nonlinear instability

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The effect of four-dimensional variational data assimilation on the reduction of the forecast errors is investigated for both stable and unstable flows. Numerical results show that the effect is generally positive. Particularly,its effect is much more significant in the presence of nonlinear instability

  5. Achievable Rates for Four-Dimensional Coded Modulation with a Bit-Wise Receiver

    CERN Document Server

    Alvarado, Alex

    2013-01-01

    We study achievable rates for four-dimensional (4D) constellations for spectrally efficient optical systems based on a (suboptimal) bit-wise receiver. We show that PM-QPSK outperforms the best 4D constellation designed for uncoded transmission by approximately 1 dB. Numerical results using LDPC codes validate the analysis.

  6. Integrable and superintegrable Hamiltonian systems with four dimensional real Lie algebras as symmetry of the systems

    Energy Technology Data Exchange (ETDEWEB)

    Abedi-Fardad, J., E-mail: j.abedifardad@bonabu.ac.ir [Department of Mathematics, Bonab University, Tabriz (Iran, Islamic Republic of); Rezaei-Aghdam, A., E-mail: rezaei-a@azaruniv.edu [Department of Physics, Azarbaijan Shahid Madani University, 53714-161 Tabriz (Iran, Islamic Republic of); Haghighatdoost, Gh., E-mail: gorbanali@azaruniv.edu [Department of Mathematics, Bonab University, Tabriz (Iran, Islamic Republic of); Department of Mathematics, Azarbaijan Shahid Madani University, Tabriz (Iran, Islamic Republic of)

    2014-05-15

    We construct integrable and superintegrable Hamiltonian systems using the realizations of four dimensional real Lie algebras as a symmetry of the system with the phase space R{sup 4} and R{sup 6}. Furthermore, we construct some integrable and superintegrable Hamiltonian systems for which the symmetry Lie group is also the phase space of the system.

  7. Clinical Stress Echocardiography

    NARCIS (Netherlands)

    S.E. Karagiannis

    2007-01-01

    textabstractTwo-dimensional echocardiography is a commonly used non-invasive method for the assessment of left ventricular function. It provides precise information on both global and segmental myocardial function by displaying endocardial motion and wall thickening. Dobutamine stress

  8. Four-dimensional optical coherence tomography imaging of total liquid ventilated rats

    Science.gov (United States)

    Kirsten, Lars; Schnabel, Christian; Gaertner, Maria; Koch, Edmund

    2013-06-01

    Optical coherence tomography (OCT) can be utilized for the spatially and temporally resolved visualization of alveolar tissue and its dynamics in rodent models, which allows the investigation of lung dynamics on the microscopic scale of single alveoli. The findings could provide experimental input data for numerical simulations of lung tissue mechanics and could support the development of protective ventilation strategies. Real four-dimensional OCT imaging permits the acquisition of several OCT stacks within one single ventilation cycle. Thus, the entire four-dimensional information is directly obtained. Compared to conventional virtual four-dimensional OCT imaging, where the image acquisition is extended over many ventilation cycles and is triggered on pressure levels, real four-dimensional OCT is less vulnerable against motion artifacts and non-reproducible movement of the lung tissue over subsequent ventilation cycles, which widely reduces image artifacts. However, OCT imaging of alveolar tissue is affected by refraction and total internal reflection at air-tissue interfaces. Thus, only the first alveolar layer beneath the pleura is visible. To circumvent this effect, total liquid ventilation can be carried out to match the refractive indices of lung tissue and the breathing medium, which improves the visibility of the alveolar structure, the image quality and the penetration depth and provides the real structure of the alveolar tissue. In this study, a combination of four-dimensional OCT imaging with total liquid ventilation allowed the visualization of the alveolar structure in rat lung tissue benefiting from the improved depth range beneath the pleura and from the high spatial and temporal resolution.

  9. Three-dimensional echocardiography

    Energy Technology Data Exchange (ETDEWEB)

    Buck, Thomas [University Hospital Essen (Germany). West German Heart Center; Franke, Andreas [Klinikum Region Hannover - Klinikum Siloah, Hannover (Germany). Dept. of Cardiology, Angiology and Intensive Care Medicine; Monaghan, Mark J. (eds.) [King' s College Hospital, London (United Kingdom)

    2011-07-01

    Presents tips and tricks for beginners and experts Provides educational material for 3D training courses Features comprehensively illustrated cases Includes an accompanying DVD with video clips of all sample cases Three-dimensional echocardiography is the most recent fundamental advancement in echocardiography. Since real-time 3D echocardiography became commercially available in 2002, it has rapidly been accepted in echo labs worldwide. This book covers all clinically relevant aspects of this fascinating new technology, including a comprehensive explanation of its basic principles, practical aspects of clinical application, and detailed descriptions of specific uses in the broad spectrum of clinically important heart disease. The book was written by a group of well-recognized international experts in the field, who have not only been involved in the scientific and clinical evolution of 3D echocardiography since its inception but are also intensively involved in expert training courses. As a result, the clear focus of this book is on the practical application of 3D echocardiography in daily clinical routine with tips and tricks for both beginners and experts, accompanied by more than 150 case examples comprehensively illustrated in more than 800 images and more than 500 videos provided on a DVD. In addition to an in-depth review of the most recent literature on real-time 3D echocardiography, this book represents an invaluable reference work for beginners and expert users of 3D echocardiography. - Tips and tricks for beginners and experts - Educational material for 3D training courses - Comprehensively illustrated cases - DVD with video clips of all sample cases.

  10. A symplectic rearrangement of the four dimensional non-geometric scalar potential

    CERN Document Server

    Shukla, Pramod

    2015-01-01

    We present a symplectic rearrangement of the effective four-dimensional non-geometric scalar potential resulting from the type IIB superstring compactification on Calabi Yau orientifolds. The strategy has two main steps. In the first step, we rewrite the four dimensional scalar potential utilizing some interesting flux combinations which we call {\\it new generalized flux orbits}. After invoking a couple of non-trivial symplectic relations, in the second step, we further rearrange all the pieces of scalar potential into a completely `symplectic-formulation' which involves only the symplectic ingredients (such as period matrix etc.) without the need of knowing Calabi Yau metric. Moreover, the scalar potential under consideration is induced by a generic tree level K\\"{a}hler potential and (non-geometric) flux superpotential for arbitrary numbers of complex structure moduli, K\\"ahler moduli and odd-axions. Finally, we exemplify our symplectic formulation for the two well known toroidal examples based on type IIB ...

  11. Novel four-dimensional autonomous chaotic system generating one-, two-, three- and four-wing attractors

    Institute of Scientific and Technical Information of China (English)

    Yu Fei; Wang Chun-Hua; Yin Jin-Wen; Xu Hao

    2011-01-01

    In this paper,we propose a novel four-dimensional autonomous chaotic system.Of particular interest is that this novel system can generate one-,two,three- and four-wing chaotic attractors with the variation of a single parameter,and the multi-wing type of the chaotic attractors can be displayed in all directions.The system is simple with a large positive Lyapunov exponent and can exhibit some interesting and complicated dynamical behaviours.Basic dynamical properties of the four-dimensional chaotic system,such as equilibrium points,the Poincaré map,the bifurcation diagram and the Lyapunov exponents are investigated by using either theoretical analysis or numerical method.Finally,a circuit is designed for the implementation of the multi-wing chaotic attractors.The electronic workbench observations are in good agreement with the numerical simulation results.

  12. On the blow-up of four dimensional Ricci flow singularities

    CERN Document Server

    Máximo, Davi

    2012-01-01

    In this paper we prove a conjecture by Feldman-Ilmanen-Knopf in \\cite{FIK} that the gradient shrinking soliton metric they constructed on the tautological line bundle over $\\CP^1$ is the uniform limit of blow-ups of a type I Ricci flow singularity on a closed manifold. We use this result to show that limits of blow-ups of Ricci flow singularities on closed four dimensional manifolds do not necessarily have non-negative Ricci curvature.

  13. Exact four-dimensional dyonic black holes and Bertotti-Robinson spacetimes in string theory

    Science.gov (United States)

    Lowe, David A.; Strominger, Andrew

    1994-09-01

    Conformal field theories corresponding to two-dimensional electrically charged black holes and to two-dimensional anti-de Sitter space with a covariantly constant electric field are simply constructed as SL(2,openR)/openZ Wess-Zumino-Witten coset models. Four-dimensional spacetime solutions are obtained by tensoring these two-dimensional theories with SU(2)/Z(m) coset models. These describe a family of dyonic black holes and the Bertotti-Robinson universe.

  14. Poisson structure and Casimir functions for a noncentral dynamical system in four-dimensional phase space

    Institute of Scientific and Technical Information of China (English)

    Lou Zhi-Mei; Chen Zi-Dong; Wang Wen-Long

    2005-01-01

    In this paper, we express the differential equations of a noncentral dynamical system in Ermakov formalism to obtain the Ermakov invariant. In term of Hamiltonian theories and using the Ermakov invariant as the Hamiltonian,the Poisson structure of a noncentral dynamical system in four-dimensional phase space are constructed. The result indicates that the Poisson structure is degenerate and the noncentral dynamical system possesses four invariants: the Hamiltonian, the Ermakov invariant and two Casimir functions.

  15. Four-Dimensional Screening Anti-Counterfeiting Pattern by Inkjet Printed Photonic Crystals.

    Science.gov (United States)

    Hou, Jue; Zhang, Huacheng; Su, Bin; Li, Mingzhu; Yang, Qiang; Jiang, Lei; Song, Yanlin

    2016-10-06

    A four-dimensional screening anti-counterfeiting QR code composed of differently shaped photonic crystal (PC) dots has been fabricated that could display four images depending on different lighting conditions. By controlling the rheology of poly(dimethylsiloxane) (PDMS), three kinds of PC dots could be sequentially integrated into one pattern using the layer-by-layer printing strategy. The information can be encoded and stored in shapes and read out by the difference in optical properties.

  16. Haunted Kaluza universe with four-dimensional Lorentzian flat, Kerr, and Taub-NUT slices

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Rossen I. [Department of Pure and Applied Mathematics, Trinity College, University of Dublin (Ireland) and Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, 72 Tsarigradsko Chaussee, Sofia 1784 (Bulgaria)]. E-mail: ivanovr@tcd.ie; Prodanov, Emil M. [School of Physical Sciences, Dublin City University, Glasnevin (Ireland)]. E-mail: prodanov@physics.dcu.ie

    2005-03-03

    The duality between the original Kaluza's theory and Klein's subsequent modification is duality between slicing and threading decomposition of the five-dimensional spacetime. The field equations of the original Kaluza's theory lead to the interpretation of the four-dimensional Lorentzian Kerr and Taub-NUT solutions as resulting from static electric and magnetic charges and dipoles in the presence of ghost matter and constant dilaton, which models Newton's constant.

  17. Non-diagonal four-dimensional cohomogeneity-one Einstein metrics in various signatures

    CERN Document Server

    Dunajski, Maciej

    2016-01-01

    Most known four-dimensional cohomogeneity-one Einstein metrics are diagonal in the basis defined by the left-invariant one-forms, though some essentially non-diagonal ones are known. We consider the problem of explicitly seeking non-diagonal Einstein metrics, and we find solutions which in some cases exhaust the possibilities. In particular we construct new examples of neutral signature non--diagonal Bianchi type VIII Einstein metrics with self--dual Weyl tensor.

  18. Fast GPU based adaptive filtering of 4D echocardiography.

    Science.gov (United States)

    Broxvall, Mathias; Emilsson, Kent; Thunberg, Per

    2012-06-01

    Time resolved three-dimensional (3D) echocardiography generates four-dimensional (3D+time) data sets that bring new possibilities in clinical practice. Image quality of four-dimensional (4D) echocardiography is however regarded as poorer compared to conventional echocardiography where time-resolved 2D imaging is used. Advanced image processing filtering methods can be used to achieve image improvements but to the cost of heavy data processing. The recent development of graphics processing unit (GPUs) enables highly parallel general purpose computations, that considerably reduces the computational time of advanced image filtering methods. In this study multidimensional adaptive filtering of 4D echocardiography was performed using GPUs. Filtering was done using multiple kernels implemented in OpenCL (open computing language) working on multiple subsets of the data. Our results show a substantial speed increase of up to 74 times, resulting in a total filtering time less than 30 s on a common desktop. This implies that advanced adaptive image processing can be accomplished in conjunction with a clinical examination. Since the presented GPU processor method scales linearly with the number of processing elements, we expect it to continue scaling with the expected future increases in number of processing elements. This should be contrasted with the increases in data set sizes in the near future following the further improvements in ultrasound probes and measuring devices. It is concluded that GPUs facilitate the use of demanding adaptive image filtering techniques that in turn enhance 4D echocardiographic data sets. The presented general methodology of implementing parallelism using GPUs is also applicable for other medical modalities that generate multidimensional data.

  19. Four-dimensional computed tomographic imaging in the wrist: proof of feasibility in a cadaveric model

    Energy Technology Data Exchange (ETDEWEB)

    Tay, Shian-Chao; Berger, Richard A. [Mayo Clinic College of Medicine, Orthopedics Biomechanics Laboratory, Rochester, MN (United States); Primak, Andrew N.; Amrami, Kimberly K. [Mayo Clinic College of Medicine, Department of Radiology, Rochester, MN (United States); Fletcher, Joel G.; McCollough, Cynthia H. [Mayo Clinic College of Medicine, Department of Radiology, Rochester, MN (United States); Mayo Clinic College of Medicine, CT Innovation Center, Rochester, MN (United States); Schmidt, Bernhard [Siemens Medical Solutions, Forchheim (Germany)

    2007-12-15

    High-resolution real-time three-dimensional (3D) imaging of the moving wrist may provide novel insights into the pathophysiology of joint instability. The purpose of this work was to assess the feasibility of using retrospectively gated spiral computed tomography (CT) to perform four-dimensional (4D) imaging of the moving wrist joint. A cadaver forearm from below the elbow was mounted on a motion simulator which performed radioulnar deviation of the wrist at 30 cycles per minute. An electronic trigger from the simulator provided the ''electrocardiogram'' (ECG) signal required for gated reconstructions. Four-dimensional and 3D images were compared by a blinded observer for image quality and presence of artifacts. Image quality of 4D images was found to be excellent at the extremes of radial and ulnar deviation (end-motion phases). Some artifacts were seen in mid-motion phases. 4D CT musculoskeletal imaging is feasible. Four-dimensional CT may allow clinicians to assess functional (dynamic) instabilities of the wrist joint. (orig.)

  20. Higher-order gravity in higher dimensions: geometrical origins of four-dimensional cosmology?

    Energy Technology Data Exchange (ETDEWEB)

    Troisi, Antonio [Universita degli Studi di Salerno, Dipartimento di Fisica ' ' E.R. Caianiello' ' , Salerno (Italy)

    2017-03-15

    Determining the cosmological field equations is still very much debated and led to a wide discussion around different theoretical proposals. A suitable conceptual scheme could be represented by gravity models that naturally generalize Einstein theory like higher-order gravity theories and higher-dimensional ones. Both of these two different approaches allow one to define, at the effective level, Einstein field equations equipped with source-like energy-momentum tensors of geometrical origin. In this paper, the possibility is discussed to develop a five-dimensional fourth-order gravity model whose lower-dimensional reduction could provide an interpretation of cosmological four-dimensional matter-energy components. We describe the basic concepts of the model, the complete field equations formalism and the 5-D to 4-D reduction procedure. Five-dimensional f(R) field equations turn out to be equivalent, on the four-dimensional hypersurfaces orthogonal to the extra coordinate, to an Einstein-like cosmological model with three matter-energy tensors related with higher derivative and higher-dimensional counter-terms. By considering the gravity model with f(R) = f{sub 0}R{sup n} the possibility is investigated to obtain five-dimensional power law solutions. The effective four-dimensional picture and the behaviour of the geometrically induced sources are finally outlined in correspondence to simple cases of such higher-dimensional solutions. (orig.)

  1. Advanced Three-Dimensional Echocardiography

    NARCIS (Netherlands)

    B. Ren (Ben)

    2014-01-01

    markdownabstract__Abstract__ During the development of echocardiography, 3D echocardiography imaging represents a major innovation in cardiovascular ultrasound (Figure 1). Advancements in computer and transducer technologies permit real-time 3D acquisition and presentation of cardiac

  2. Clinical Stress Echocardiography

    NARCIS (Netherlands)

    S.E. Karagiannis

    2007-01-01

    textabstractTwo-dimensional echocardiography is a commonly used non-invasive method for the assessment of left ventricular function. It provides precise information on both global and segmental myocardial function by displaying endocardial motion and wall thickening. Dobutamine stress echocardiograp

  3. Non-critical string duals of four-dimensional CFTs with fundamental matter

    Energy Technology Data Exchange (ETDEWEB)

    Bigazzi, F. [LPTHE, Universites Paris VI et VII, 4 Place Jussieu, 75252 Paris cedex 05 (France); INFN, Piazza dei Caprettari, 70, 00186 Roma (Italy); Casero, R.; Paredes, A. [CPHT, Ecole Polytechnique, UMR de CNRS 7644, 91128 Palaiseau (France); Cotrone, A.L. [Departament ECM, Facultat de Fisica, Universitat de Barcelona and Institut de Fisica d' Altes Energies, Diagonal 647, 08028 Barcelona (Spain)

    2006-05-04

    The two-derivative approximation to non-critical strings is used as a qualitative tool to find solutions dual to four dimensional CFTs with matter in the fundamental. Two solutions are discussed: an AdS{sub 5} x S{sup 3}, which is dual to an N=1 SCFT only for a ratio of N{sub f}/N{sub c} and an AdS{sub 5} which is proposed to be dual to N=0 QCD in the conformal window. All solutions have curvatures of the order of the string scale. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  4. A Note On The Semiclassical Formulation Of BPS States In Four-Dimensional N=2 Theories

    CERN Document Server

    Brennan, T Daniel

    2016-01-01

    Vector spaces of (framed) BPS states of Lagrangian four-dimensional N=2 field theories can be defined in semiclassical chambers in terms of the $L^2$-cohomology of Dirac-like operators on monopole moduli spaces. This was spelled out previously for theories with only vectormultiplets, taking into account only a subset of the possible half-supersymmetric 't Hooft-Wilson line defects. This note completes the discussion by describing the modifications needed when including matter hypermultiplets together with arbitrary 't Hooft-Wilson line defects. Two applications of this extended discussion are given.

  5. Gravitational matter-antimatter asymmetry and four-dimensional Yang-Mills gauge symmetry

    Science.gov (United States)

    Hsu, J. P.

    1981-01-01

    A formulation of gravity based on the maximum four-dimensional Yang-Mills gauge symmetry is studied. The theory predicts that the gravitational force inside matter (fermions) is different from that inside antimatter. This difference could lead to the cosmic separation of matter and antimatter in the evolution of the universe. Moreover, a new gravitational long-range spin-force between two fermions is predicted, in addition to the usual Newtonian force. The geometrical foundation of such a gravitational theory is the Riemann-Cartan geometry, in which there is a torsion. The results of the theory for weak fields are consistent with previous experiments.

  6. Four-dimensional dose evaluation using deformable image registration in radiotherapy for liver cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hoon Jung, Sang; Min Yoon, Sang; Ho Park, Sung; Cho, Byungchul; Won Park, Jae; Jung, Jinhong; Park, Jin-hong; Hoon Kim, Jong; Do Ahn, Seung [Departments of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul 138-736 (Korea, Republic of)

    2013-01-15

    Purpose: In order to evaluate the dosimetric impact of respiratory motion on the dose delivered to the target volume and critical organs during free-breathing radiotherapy, a four-dimensional dose was evaluated using deformable image registration (DIR). Methods: Four-dimensional computed tomography (4DCT) images were acquired for 11 patients who were treated for liver cancer. Internal target volume-based treatment planning and dose calculation (3D dose) were performed using the end-exhalation phase images. The four-dimensional dose (4D dose) was calculated based on DIR of all phase images from 4DCT to the planned image. Dosimetric parameters from the 4D dose, were calculated and compared with those from the 3D dose. Results: There was no significant change of the dosimetric parameters for gross tumor volume (p > 0.05). The increase D{sub mean} and generalized equivalent uniform dose (gEUD) for liver were by 3.1%{+-} 3.3% (p= 0.003) and 2.8%{+-} 3.3% (p= 0.008), respectively, and for duodenum, they were decreased by 15.7%{+-} 11.2% (p= 0.003) and 15.1%{+-} 11.0% (p= 0.003), respectively. The D{sub max} and gEUD for stomach was decreased by 5.3%{+-} 5.8% (p= 0.003) and 9.7%{+-} 8.7% (p= 0.003), respectively. The D{sub max} and gEUD for right kidney was decreased by 11.2%{+-} 16.2% (p= 0.003) and 14.9%{+-} 16.8% (p= 0.005), respectively. For left kidney, D{sub max} and gEUD were decreased by 11.4%{+-} 11.0% (p= 0.003) and 12.8%{+-} 12.1% (p= 0.005), respectively. The NTCP values for duodenum and stomach were decreased by 8.4%{+-} 5.8% (p= 0.003) and 17.2%{+-} 13.7% (p= 0.003), respectively. Conclusions: The four-dimensional dose with a more realistic dose calculation accounting for respiratory motion revealed no significant difference in target coverage and potentially significant change in the physical and biological dosimetric parameters in normal organs during free-breathing treatment.

  7. A Four-Dimensional Continuum Theory of Space-Time and the Classical Physical Fields

    Directory of Open Access Journals (Sweden)

    Suhendro I.

    2007-10-01

    Full Text Available In this work, we attempt to describe the classical physical fields of gravity, electromagnetism, and the so-called intrinsic spin (chirality in terms of a set of fully geometrized constitutive equations. In our formalism, we treat the four-dimensional space-time continuum as a deformable medium and the classical fields as intrinsic stress and spin fields generated by infinitesimal displacements and rotations in the space-time continuum itself. In itself, the unifying continuum approach employed herein may suggest a possible unified field theory of the known classical physical fields.

  8. The violation of the No-Hair Conjecture in four-dimensional ungauged Supergravity

    CERN Document Server

    Bueno, Pablo

    2013-01-01

    By choosing a particular, String Theory inspired, Special K\\"ahler manifold, we are able to find a N=2 four-dimensional ungauged Supergravity model that contains supersymmetric black hole solutions that violate the folk uniqueness theorems that are expected to hold in ungauged Supergravity. The black hole solutions are regular in the sense that they have a positive mass and a unique physical singularity hidden by an event horizon. In contradistinction to the examples already known in the literature, we find our solutions in a theory without scalar potential, gaugings or higher order curvature terms.

  9. Exact four-dimensional dyonic black holes and Bertotti-Robinson spacetimes in string theory

    Energy Technology Data Exchange (ETDEWEB)

    Lowe, D.A.; Strominger, A. (Department of Physics, University of California, Santa Barbara, California 93106-9530 (United States))

    1994-09-12

    Conformal field theories corresponding to two-dimensional electrically charged black holes and to two-dimensional anti-de Sitter space with a covariantly constant electric field are simply constructed as SL(2,[ital openR])/[ital openZ] Wess-Zumino-Witten coset models. Four-dimensional spacetime solutions are obtained by tensoring these two-dimensional theories with SU(2)/[ital Z]([ital m]) coset models. These describe a family of dyonic black holes and the Bertotti-Robinson universe.

  10. An accessible four-dimensional treatment of Maxwell's equations in terms of differential forms

    Science.gov (United States)

    Sá, Lucas

    2017-03-01

    Maxwell’s equations are derived in terms of differential forms in the four-dimensional Minkowski representation, starting from the three-dimensional vector calculus differential version of these equations. Introducing all the mathematical and physical concepts needed (including the tool of differential forms), using only knowledge of elementary vector calculus and the local vector version of Maxwell’s equations, the equations are reduced to a simple and elegant set of two equations for a unified quantity, the electromagnetic field. The treatment should be accessible for students taking a first course on electromagnetism.

  11. Six-dimensional Methods for Four-dimensional Conformal Field Theories II: Irreducible Fields

    CERN Document Server

    Weinberg, Steven

    2012-01-01

    This note supplements an earlier paper on conformal field theories. There it was shown how to construct tensor, spinor, and spinor-tensor primary fields in four dimensions from their counterparts in six dimensions, where conformal transformations act simply as SO(4,2) Lorentz transformations. Here we show how to constrain fields in six dimensions so that the corresponding primary fields in four dimensions transform according to irreducible representations of the four-dimensional Lorentz group, even when the irreducibility conditions on these representations involve the four-component Levi-Civita tensor $\\epsilon_{\\mu\

  12. Four-dimensional (4D) tracking of high-temperature microparticles

    Science.gov (United States)

    Wang, Zhehui; Liu, Q.; Waganaar, W.; Fontanese, J.; James, D.; Munsat, T.

    2016-11-01

    High-speed tracking of hot and molten microparticles in motion provides rich information about burning plasmas in magnetic fusion. An exploding-wire apparatus is used to produce moving high-temperature metallic microparticles and to develop four-dimensional (4D) or time-resolved 3D particle tracking techniques. The pinhole camera model and algorithms developed for computer vision are used for scene calibration and 4D reconstructions. 3D positions and velocities are then derived for different microparticles. Velocity resolution approaches 0.1 m/s by using the local constant velocity approximation.

  13. A four-dimensional description of five-dimensional N-brane models

    CERN Document Server

    Bloomfield, Jolyon K

    2010-01-01

    We propose a new method for obtaining the four-dimensional effective gravitational theory for five-dimensional braneworld models with arbitrary numbers of branes in a low energy regime, based on a two-lengthscale expansion. The method is straightforward and computationally efficient, and is applicable to both compactified and uncompactified models. Particular emphasis is placed on the behavior of the radion modes of the model, while the massive effective fields are automatically truncated. Generally, the radion modes are found to form a (N-1)-dimensional nonlinear sigma model. We illustrate the method for a N-brane model in an uncompactified extra dimension.

  14. Bifurcation structures and transient chaos in a four-dimensional Chua model

    Energy Technology Data Exchange (ETDEWEB)

    Hoff, Anderson, E-mail: hoffande@gmail.com; Silva, Denilson T. da; Manchein, Cesar, E-mail: cesar.manchein@udesc.br; Albuquerque, Holokx A., E-mail: holokx.albuquerque@udesc.br

    2014-01-10

    A four-dimensional four-parameter Chua model with cubic nonlinearity is studied applying numerical continuation and numerical solutions methods. Regarding numerical solution methods, its dynamics is characterized on Lyapunov and isoperiodic diagrams and regarding numerical continuation method, the bifurcation curves are obtained. Combining both methods the bifurcation structures of the model were obtained with the possibility to describe the shrimp-shaped domains and their endoskeletons. We study the effect of a parameter that controls the dimension of the system leading the model to present transient chaos with its corresponding basin of attraction being riddled.

  15. Quasinormal modes of four-dimensional topological nonlinear charged Lifshitz black holes

    Energy Technology Data Exchange (ETDEWEB)

    Becar, Ramon [Universidad Cato lica de Temuco, Departamento de Ciencias Matematicas y Fisicas, Temuco (Chile); Gonzalez, P.A. [Universidad Diego Portales, Facultad de Ingenieria, Santiago (Chile); Vasquez, Yerko [Universidad de La Serena, Departamento de Fisica, Facultad de Ciencias, La Serena (Chile)

    2016-02-15

    We study scalar perturbations of four- dimensional topological nonlinear charged Lifshitz black holes with spherical and plane transverse sections, and we find numerically the quasinormal modes for scalar fields. Then we study the stability of these black holes under massive and massless scalar field perturbations. We focus our study on the dependence of the dynamical exponent, the nonlinear exponent, the angular momentum, and the mass of the scalar field in the modes. It is found that the modes are overdamped, depending strongly on the dynamical exponent and the angular momentum of the scalar field for a spherical transverse section. In contrast, for plane transverse sections the modes are always overdamped. (orig.)

  16. Non-critical holography and four-dimensional CFT's with fundamentals

    CERN Document Server

    Bigazzi, F; Cotrone, A L; Kiritsis, E; Paredes, A

    2005-01-01

    We find non-critical string backgrounds in five and eight dimensions, holographically related to four-dimensional conformal field theories with N=0 and N=1 supersymmetries. In the five-dimensional case we find an AdS_5 background metric for a string model related to non-supersymmetric, conformal QCD with large number of colors and flavors and discuss the conjectured existence of a conformal window from the point of view of our solution. In the eight-dimensional string theory, we build a family of solutions of the form AdS_5 x \\tilde{S}^3 with \\tilde{S}^3 a squashed three-sphere. For a special value of the ratio N_f/N_c, the background can be interpreted as the supersymmetric near-horizon limit of a system of color and flavor branes on R^{1,3} times a known four-dimensional generalization of the cigar. The N=1 dual theory with fundamental matter should have an IR fixed point only for a fixed ratio N_f/N_c. General features of the string/gauge theory correspondence for theories with fundamental flavors are also...

  17. Non-critical holography and four-dimensional CFT's with fundamentals

    Energy Technology Data Exchange (ETDEWEB)

    Bigazzi, Francesco [LPTHE, Universites Paris VI et VII, 4 place Jussieu, 75252 Paris cedex 05 (France); INFN, Piazza dei Caprettari 70, I-00186 Rome (Italy); Casero, Roberto [CPHT, Ecole Polytechnique, UMR du CNRS 7644, 91128 Palaiseau (France); Cotrone, Aldo Lorenzo [Departament ECM, Facultat de Fisica, Universitat de Barcelona, and Institut de Fisica d' Altes Energies, Diagonal 647, E-08028 Barcelona (Spain); Kiritsis, Elias [CPHT, Ecole Polytechnique, UMR du CNRS 7644, 91128 Palaiseau (France); Department of Physics, University of Crete, 71003 Heraklion (Greece); Paredes, Angel [CPHT, Ecole Polytechnique, UMR du CNRS 7644, 91128 Palaiseau (France)

    2005-10-15

    We find non-critical string backgrounds in five and eight dimensions, holographically related to four-dimensional conformal field theories with N 0 and N = 1 supersymmetries. In the five-dimensional case we find an AdS{sub 5} background metric for a string model related to non-supersymmetric, conformal QCD with large number of colors and flavors and discuss the conjectured existence of a conformal window from the point of view of our solution. In the eight-dimensional string theory, we build a family of solutions of the form AdS{sub 5} x S-tilde {sup 3} with S-tilde {sup 3} a squashed three-sphere. For a special value of the ratio N{sub f}/N{sub c}, the background can be interpreted as the supersymmetric near-horizon limit of a system of color and flavor branes on R{sup 1,3} times a known four-dimensional generalization of the cigar. The N = 1 dual theory with fundamental matter should have an IR fixed point only for a fixed ratio N{sub f}/N{sub c}. General features of the string/gauge theory correspondence for theories with fundamental flavors are also addressed.

  18. Current status of fetal neurodevelopmental assessment: Four-dimensional ultrasound study.

    Science.gov (United States)

    Hata, Toshiyuki

    2016-10-01

    With the latest advent of four-dimensional (4-D) ultrasound, fetal neurobehavioral or neurodevelopmental assessment can be easily and readily performed. Using this technique, typical fetal movements and behavioral patterns have become apparent in all three trimesters of pregnancy. In twin pregnancy, 4-D ultrasound facilitates the precise evaluation of inter-twin contact and intra-pair stimulation. New fetal neurobehavioral assessment tests, such as Kurjak's Antenatal Neurodevelopmental Test and the Fetal Observable Movement System, may reflect the normal and abnormal neurological development of the fetus, and will facilitate more precise assessments of fetal neurobehavior or neurodevelopment, and fetal brain and central nervous system functions. In this review article, I also discuss interesting topics regarding maternal and fetal stress, fetal pain, and fetal consciousness. Four-dimensional ultrasound has opened the door to new scientific fields, such as 'fetal neurology' and 'fetal psychology,' and fetal neurobehavioral science is at the dawn of a new era. Knowledge on fetal neurobehavior and neurodevelopment will be advanced through fetal behavioral research using this technique.

  19. Three- and four-dimensional visualization of magnetic resonance imaging data sets in pediatric cardiology.

    Science.gov (United States)

    Vick, G W

    2000-01-01

    The purpose of medical imaging technology in pediatric cardiology is to provide clear representations of the underlying anatomy and physiology of the cardiovascular system--representations that are easily understood and that facilitate clinical decision making. However, standard projective and tomographic imaging methods often yield results that are intelligible only to imaging specialists. Three- and four-dimensional reconstructions from projective and tomographic data sets are an alternative form of image display. Often, these reconstructions are more readily comprehensible as representations of the reality apparent in the operating room or the pathology laboratory than are the original data sets. Furthermore, viewing of these reconstructions is much more time efficient than viewing hundreds of separate tomographic images. Magnetic resonance imaging inherently provides three-, four-, and even higher dimensional data, and magnetic resonance data sets are commonly used to generate volumetric reconstructions. This review will focus on the practical application of magnetic resonance imaging to yield three- and four-dimensional reconstructions of pediatric cardiovascular disorders.

  20. A novel four-dimensional analytical approach for analysis of complex samples.

    Science.gov (United States)

    Stephan, Susanne; Jakob, Cornelia; Hippler, Jörg; Schmitz, Oliver J

    2016-05-01

    A two-dimensional LC (2D-LC) method, based on the work of Erni and Frei in 1978, was developed and coupled to an ion mobility-high-resolution mass spectrometer (IM-MS), which enabled the separation of complex samples in four dimensions (2D-LC, ion mobility spectrometry (IMS), and mass spectrometry (MS)). This approach works as a continuous multiheart-cutting LC system, using a long modulation time of 4 min, which allows the complete transfer of most of the first - dimension peaks to the second - dimension column without fractionation, in comparison to comprehensive two-dimensional liquid chromatography. Hence, each compound delivers only one peak in the second dimension, which simplifies the data handling even when ion mobility spectrometry as a third and mass spectrometry as a fourth dimension are introduced. The analysis of a plant extract from Ginkgo biloba shows the separation power of this four-dimensional separation method with a calculated total peak capacity of more than 8700. Furthermore, the advantage of ion mobility for characterizing unknown compounds by their collision cross section (CCS) and accurate mass in a non-target approach is shown for different matrices like plant extracts and coffee. Graphical abstract Principle of the four-dimensional separation.

  1. Four-dimensional conversion for spiritual leadership development: A missiological approach for African churches

    Directory of Open Access Journals (Sweden)

    Kalemba Mwambazambi

    2014-04-01

    Full Text Available The process of a four-dimensional conversion and/or transformation strives in helping the leadership of an organisation, especially such as the church, with practical ways that may lead to the development of an effective leadership by observing the four important aspects of human spirituality as elaborated on in the article. The spiritual, intellectual, moral and socio-political dimensions of the transformation can be catered for so that the complete inner being of humans, as well as their social and political attitudes and behaviours, can equally be transformed to maximum spiritual, personal and socio-political profitability. Mutombo-Mukendi demonstrates that the need for a spiritual leadership that can contribute to an effective transformation of Africa is dire, both for the church and the larger community. The real challenge is how to develop such leadership. This article provides intentional and practical ways that may lead to the development of the needed leadership. Four-dimensional transformation of people can be planned and carried out both in the church arena and in the surrounding communities. Skills development and transfer can also take place when skilled people from the church work with unskilled people from the community.

  2. On the existence of bifocal heteroclinic cycles in a class of four-dimensional piecewise affine systems

    Science.gov (United States)

    Wu, Tiantian; Yang, Xiao-Song

    2016-05-01

    Based on mathematical analysis, this paper provides a methodology to ensure the existence of heteroclinic cycles in a class of four-dimensional piecewise affine systems. In addition, examples are provided to illustrate the effectiveness of the method.

  3. Classification of four-dimensional real Lie bialgebras of symplectic type and their Poisson-Lie groups

    Science.gov (United States)

    Abedi-Fardad, J.; Rezaei-Aghdam, A.; Haghighatdoost, Gh.

    2017-01-01

    We classify all four-dimensional real Lie bialgebras of symplectic type and obtain the classical r-matrices for these Lie bialgebras and Poisson structures on all the associated four-dimensional Poisson-Lie groups. We obtain some new integrable models where a Poisson-Lie group plays the role of the phase space and its dual Lie group plays the role of the symmetry group of the system.

  4. Quasinormal modes of a four-dimensional Lifshitz Black Hole in Conformal Gravity

    CERN Document Server

    Catalan, Marcela; Gonzalez, P A; Vasquez, Yerko

    2014-01-01

    We study the quasinormal modes of scalar perturbations for a four-dimensional asymptotically Lifshitz black hole in conformal gravity with dynamical exponent $z=0$ and spherical topology for the transverse section, and we find analytically the quasinormal modes for scalar fields for some special cases that depend of $Q$, where $Q=r_+^2/r_-^2$. One of them are the quasinormal modes for massive scalar fields for the mode with lowest angular momentum $(\\kappa=0)$, where we show that the Klein-Gordon equation can be written as a Riemann differential equation, and the quasinormal frequencies associated guarantees the stability of these black holes under scalar field perturbations for $Q>1$. Other case correspond to $Q=\\pm\\infty$, where the quasinormal frequencies guarantees the unstability of these black holes under scalar field perturbations. Finally, for the extremal case, that is $Q=1$, we show the absence of the quasinormal modes.

  5. Commissioning and quality assurance of Calypso four-dimensional target localization system in linear accelerator facility.

    Science.gov (United States)

    Muralidhar, K R; Komanduri, Krishna; Rout, Birendra Kumar; Ramesh, K K D

    2013-07-01

    Four dimensional (4D) target localization system (Calypso System) was installed at our hospital, which is equipped with Beacon Transponders, Console, Electromagnetic Array, Optical System, Tracking Station, Treatment table overlay, and Calypso kVue Couch top. The objective of this presentation is to describe the results of commissioning measurements carried out on the Calypso System to verify the manufacturer specifications and also to evolve a quality assurance (QA) procedure which can be used to test its performance routinely. The QA program consists of a series of tests (QA for checking the calibration or system accuracy, Camera Calibration with L-frame fixture, Camera Calibration with T-frame fixture, System calibration Fixture targets test, Localization, and Tracking). These tests were found to be useful to assess the performance of the Calypso System.

  6. Automated four-dimensional Monte Carlo workflow using log files and real-time motion monitoring

    Science.gov (United States)

    Sibolt, P.; Cronholm, R. O.; Heath, E.; Andersen, C. E.; Behrens, C. F.

    2017-05-01

    With emerging techniques for tracking and gating methods in radiotherapy of lung cancer patients, there is an increasing need for efficient four-dimensional Monte Carlo (4DMC) based quality assurance (QA). An automated and flexible workflow for 4DMC QA, based on the 4DdefDOSXYZnrc user code, has been developed in python. The workflow has been tested and verified using an in-house developed dosimetry system comprised of a dynamic thorax phantom constructed for plastic scintillator dosimetry. The workflow is directly compatible with any treatment planning system and can also be triggered by the appearance of linac log files. It has minimum user interaction and, with the use of linac log files, it provides a method for verification of the actually delivered dose in the patient geometry.

  7. Modeling lung motion using consistent image registration in four-dimensional computed tomography for radiation therapy

    Science.gov (United States)

    Lu, Wei; Song, Joo Hyun; Christensen, Gary E.; Parikh, Parag J.; Bradley, Jeffrey D.; Low, Daniel A.

    2006-03-01

    Respiratory motion is a significant source of error in conformal radiation therapy for the thorax and upper abdomen. Four-dimensional computed tomography (4D CT) has been proposed to reduce the uncertainty caused by internal respiratory organ motion. A 4D CT dataset is retrospectively reconstructed at various stages of a respiratory cycle. An important tool for 4D treatment planning is deformable image registration. An inverse consistent image registration is used to model lung motion from one respiratory stage to another during a breathing cycle. This diffeomorphic registration jointly estimates the forward and reverse transformations providing more accurate correspondence between two images. Registration results and modeled motions in the lung are shown for three example respiratory stages. The results demonstrate that the consistent image registration satisfactorily models the large motions in the lung, providing a useful tool for 4D planning and delivering.

  8. Berry curvature and four-dimensional monopoles in the relativistic chiral kinetic equation.

    Science.gov (United States)

    Chen, Jiunn-Wei; Pu, Shi; Wang, Qun; Wang, Xin-Nian

    2013-06-28

    We derive a relativistic chiral kinetic equation with manifest Lorentz covariance from Wigner functions of spin-1/2 massless fermions in a constant background electromagnetic field. It contains vorticity terms and a four-dimensional Euclidean Berry monopole which gives an axial anomaly. By integrating out the zeroth component of the 4-momentum p, we reproduce the previous three-dimensional results derived from the Hamiltonian approach, together with the newly derived vorticity terms. The phase space continuity equation has an anomalous source term proportional to the product of electric and magnetic fields (FσρF[over ˜]σρ∼EσBσ). This provides a unified interpretation of the chiral magnetic and vortical effects, chiral anomaly, Berry curvature, and the Berry monopole in the framework of Wigner functions.

  9. Portraying entanglement between molecular qubits with four-dimensional inelastic neutron scattering

    Science.gov (United States)

    Garlatti, E.; Guidi, T.; Ansbro, S.; Santini, P.; Amoretti, G.; Ollivier, J.; Mutka, H.; Timco, G.; Vitorica-Yrezabal, I. J.; Whitehead, G. F. S.; Winpenny, R. E. P.; Carretta, S.

    2017-01-01

    Entanglement is a crucial resource for quantum information processing and its detection and quantification is of paramount importance in many areas of current research. Weakly coupled molecular nanomagnets provide an ideal test bed for investigating entanglement between complex spin systems. However, entanglement in these systems has only been experimentally demonstrated rather indirectly by macroscopic techniques or by fitting trial model Hamiltonians to experimental data. Here we show that four-dimensional inelastic neutron scattering enables us to portray entanglement in weakly coupled molecular qubits and to quantify it. We exploit a prototype (Cr7Ni)2 supramolecular dimer as a benchmark to demonstrate the potential of this approach, which allows one to extract the concurrence in eigenstates of a dimer of molecular qubits without diagonalizing its full Hamiltonian. PMID:28216631

  10. Flame four-dimensional deflection tomography with compressed-sensing-revision reconstruction

    Science.gov (United States)

    Zhang, Bin; Zhao, Minmin; Liu, Zhigang; Wu, Zhaohang

    2016-08-01

    Deflection tomography with limited angle projections was investigated to visualize a premixed flame. A projection sampling system for deflection tomography was used to obtain chronological deflectogram arrays at six view angles with only a pair of gratings. A new iterative reconstruction algorithm with deflection angle compressed-sensing revision was developed to improve reconstruction-distribution quality from incomplete projection data. Numerical simulation and error analysis provided a good indication of algorithm precision and convergence. In the experiment, 150 fringes were processed, and temperature distributions in 20 cross-sections were reconstructed from projection data in four instants. Four-dimensional flame structures and temperature distributions in the flame interior were visualized using the visualization toolkit. The experimental reconstruction was then compared with the result obtained from computational fluid dynamic analysis.

  11. Structures of larger proteins in solution: Three- and four-dimensional heteronuclear NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gronenborn, A.M.; Clore, G.M. [National Institutes of Health, Bethesda, MD (United States)

    1994-12-01

    Complete understanding of a protein`s function and mechanism of action can only be achieved with a knowledge of its three-dimensional structure at atomic resolution. At present, there are two methods available for determining such structures. The first method, which has been established for many years, is x-ray diffraction of protein single crystals. The second method has blossomed only in the last 5 years and is based on the application of nuclear magnetic resonance (NMR) spectroscopy to proteins in solution. This review paper describes three- and four-dimensional NMR methods applied to protein structure determination and was adapted from Clore and Gronenborn. The review focuses on the underlying principals and practice of multidimensional NMR and the structural information obtained.

  12. New classes of bi-axially symmetric solutions to four-dimensional Vasiliev higher spin gravity

    CERN Document Server

    Sundell, Per

    2016-01-01

    We present new infinite-dimensional spaces of bi-axially symmetric asymptotically anti-de Sitter solutions to four-dimensional Vasiliev higher spin gravity, obtained by modifications of the Ansatz used in arXiv:1107.1217, which gave rise to a Type-D solution space. The current Ansatz is based on internal semigroup algebras (without identity) generated by exponentials formed out of the bi-axial symmetry generators. After having switched on the vacuum gauge function, the resulting generalized Weyl tensor is given by the sum of two generalized Petrov type-D tensors, and the twistor space connections are smooth in twistor space over finite regions of spacetime. We provide evidence for that the linearized twistor space connection can be brought to Vasiliev gauge.

  13. Transformation of general astigmatic Gaussian beams in a four-dimensional phase space

    Institute of Scientific and Technical Information of China (English)

    Baoxin Chen

    2006-01-01

    @@ A phase space model of two-dimensional (2D) Gaussian beam propagation is generalized for threedimensional (3D) general astigmatic Gaussian beam passing through first-order optical system. The general astigmatic Gaussian beam is represented by a four-dimensional (4D) phase super-ellipsoid that defined by an associated 4 × 4 real matrix, then the transformation formula of the phase super-ellipsoid of the beam through first-order optical system is derived. In particular, in the phase space framework, the beam propagation factor M2 value is proved to be a ratio of phase area of real beam to ideal beam, and a novel approach for a qualitative examination of the properties of fractional Fourier transform (FRT) for the beam is also provided.

  14. Impact on four dimensional dose accumulation using deformable image registration in liver stereotactic body radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Seong Hee; Kim, Tae Ho; Kim, Dong Su; Seong, Cheon Keum; Cho, Min Seok; Kim, Kyeong Hyeon; Suh, Tae Suk [Dept of. Biomedical Engineering, Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul (Korea, Republic of); Park, So Hyun [Dept. of Radiation Oncology, Uijeongbu ST Mary' s Hospital, the Catholic University of Korea, Uijeongbu (Korea, Republic of); Kim, Si Yong [Dept. of Radiation Oncology, Virginia Commonwealth University, Richmond (United States)

    2014-11-15

    This study aims to evaluate the dosimetric effect of four-dimensional dose accumulation (4D dose) compared to 3D dose in liver stereotactic body radiotherapy (SBRT). Currently, SBRTT has been widely used to deliver highly conformal dose to target while sparing normal tissue. So, SBRT need accurate target delineation, dose calculation and motion management techniques such as breath-hold or abdominal compressor. In spite of the benefits about these techniques, there are still deformation and movement which could lead to reduce the probability for tumor control, imprecise prediction of normal tissue complication. 4D dose accumulation which can consider dosimetric effect of respiratory motion has a possibility to predict the more accurate delivered dose to target and normal organs and improve treatment accuracy.

  15. A pure Dirac's analysis for a four dimensional BF-like theory with a compact dimension

    CERN Document Server

    Escalante, Alberto

    2013-01-01

    In the context of extra dimensions, we perform a detailed Dirac's canonical analysis for a topological four dimensional BF-like theory. By performing the compactification process a la Kaluza-Klein, we find out the relevant symmetries of the theory, namely, the full structure of the constraints and the extended action. We show that the extended Hamiltonian is a linear combination of first class constraints, which means that the general covariance of the theory is not affected by the compactification process. Furthermore, in order to carry out the correct counting of physical degrees of freedom, we show that must be taken into account the reducibility conditions among the first class constraints associated to the excited KK modes. Finally, we perform the Hamiltonian analysis of Maxwell theory written as a $BF$-like theory, we analyze the constraints of the theory and the results obtained are compared with those found in the literature.

  16. Four-dimensional (4D) image reconstruction strategies in dynamic PET: beyond conventional independent frame reconstruction.

    Science.gov (United States)

    Rahmim, Arman; Tang, Jing; Zaidi, Habib

    2009-08-01

    In this article, the authors review novel techniques in the emerging field of spatiotemporal four-dimensional (4D) positron emission tomography (PET) image reconstruction. The conventional approach to dynamic PET imaging, involving independent reconstruction of individual PET frames, can suffer from limited temporal resolution, high noise (especially when higher frame sampling is introduced to better capture fast dynamics), as well as complex reconstructed image noise distributions that can be very difficult and time consuming to model in kinetic parameter estimation tasks. Various approaches that seek to address some or all of these limitations are described, including techniques that utilize (a) iterative temporal smoothing, (b) advanced temporal basis functions, (c) principal components transformation of the dynamic data, (d) wavelet-based techniques, as well as (e) direct kinetic parameter estimation methods. Future opportunities and challenges with regards to the adoption of 4D and higher dimensional image reconstruction techniques are also outlined.

  17. The a-theorem for the four-dimensional gauged vector model

    CERN Document Server

    Schnitzer, Howard J

    2014-01-01

    The discussion of renormalization group flows in four-dimensional conformal field theories has recently focused on the a-anomaly. It has recently been shown that there is a monotonic decreasing function which interpolates between the ultraviolet and infrared fixed points such that \\Delta a = a_UV - a_IR > 0. The analysis has been extended to weakly relevant and marginal deformations, though there are few explicit examples involving interacting theories. In this paper we examine the a-theorem in the context of the gauged vector model which couples the usual vector model to the Banks-Zaks model. We consider the model to leading order in the 1/N expansion, all orders in the coupling constant \\lambda, and to second order in g^2. The model has both an IR and UV fixed point, and satisfies \\Delta a > 0.

  18. Weak constraint four-dimensional variational data assimilation in a model of the California Current System

    Science.gov (United States)

    Crawford, William J.; Smith, Polly J.; Milliff, Ralph F.; Fiechter, Jerome; Wikle, Christopher K.; Edwards, Christopher A.; Moore, Andrew M.

    2016-12-01

    A new approach is explored for computing estimates of the error covariance associated with the intrinsic errors of a numerical forecast model in regions characterized by upwelling and downwelling. The approach used is based on a combination of strong constraint data assimilation, twin model experiments, linear inverse modeling, and Bayesian hierarchical modeling. The resulting model error covariance estimates Q are applied to a model of the California Current System using weak constraint four-dimensional variational (4D-Var) data assimilation to compute estimates of the ocean circulation. The results of this study show that the estimates of Q derived following our approach lead to demonstrable improvements in the model circulation estimates and isolate regions where model errors are likely to be important and that have been independently identified in the same model in previously published work.

  19. Four-dimensional data assimilation with optimized viscosity using High Resolution Doppler Lidar observations

    Science.gov (United States)

    Chai, Tianfeng; Lin, Ching-Long

    2001-11-01

    We present a four-dimensional variational data assimilation (4D-Var) technique with optimized eddy viscosity for the retrieval of the detailed atmospheric boundary-layer structures from High-Resolution Doppler Lidar (HRDL) radial velocity observations. The 4D-Var is based on the calculus of variations and optimal control theory to recover complete and dynamically consistent data set by minimizing the difference between limited observations and corresponding model predictions. To reflect the nature of the atmospheric boundary layer under various stability conditions, eddy viscosity is treated as part of control variables to be optimized in the 4D-Var model. The mathematical formulation for optimizing eddy viscosity is presented. The model is validated by conducting numerical experiments that utilize synthetic observations. We then apply the 4D-Var to the HRDL data measured under convective and stable conditions.

  20. On the existence of rigid spheres in four-dimensional spacetime manifolds

    CERN Document Server

    Gittel, Hans-Peter; Kijowski, Jerzy

    2015-01-01

    This paper deals with the generalization of usual round spheres in the flat Minkowski spacetime to the case of a generic four-dimensional spacetime manifold $M$. We consider geometric properties of sphere-like submanifolds in $M$ and introduce conditions on external curvature and torsion, which lead to a definition of a {\\em rigid sphere}. The main result is a local existence theorem concernig such spheres. For this purpose we apply the surjective implicit function theorem. The proof is based on a detailed analysis of the linearized problem and leads to an eight-parameter family of solutions in case when the metric tensor $g$ of $M$ is from a certain neighbourhood of the flat Minkowski metric. This contribution continues the study of rigid spheres in (Class. Quantum Grav. \\textbf{30} (2013), 175010, doi:10.1088/0264-9381/30/17/175010, 18 pp.).

  1. The transfer matrix method in four-dimensional causal dynamical triangulations

    CERN Document Server

    Ambjorn, J; Goerlich, A T; Jurkiewicz, J; Loll, R

    2013-01-01

    The Causal Dynamical Triangulation model of quantum gravity (CDT) is a proposition to evaluate the path integral over space-time geometries using a lattice regularization with a discrete proper time and geometries realized as simplicial manifolds. The model admits a Wick rotation to imaginary time for each space-time configuration. Using computer simulations we determined the phase structure of the model and discovered that it predicts a de Sitter phase with a four-dimensional spherical semi-classical background geometry. The model has a transfer matrix, relating spatial geometries at adjacent (discrete lattice) times. The transfer matrix uniquely determines the theory. We show that the measurements of the scale factor of the (CDT) universe are well described by an effective transfer matrix where the matrix elements are labelled only by the scale factor. Using computer simulations we determine the effective transfer matrix elements and show how they relate to an effective minisuperspace action at all scales.

  2. Nanomechanics and intermolecular forces of amyloid revealed by four-dimensional electron microscopy.

    Science.gov (United States)

    Fitzpatrick, Anthony W P; Vanacore, Giovanni M; Zewail, Ahmed H

    2015-03-17

    The amyloid state of polypeptides is a stable, highly organized structural form consisting of laterally associated β-sheet protofilaments that may be adopted as an alternative to the functional, native state. Identifying the balance of forces stabilizing amyloid is fundamental to understanding the wide accessibility of this state to peptides and proteins with unrelated primary sequences, various chain lengths, and widely differing native structures. Here, we use four-dimensional electron microscopy to demonstrate that the forces acting to stabilize amyloid at the atomic level are highly anisotropic, that an optimized interbackbone hydrogen-bonding network within β-sheets confers 20 times more rigidity on the structure than sequence-specific sidechain interactions between sheets, and that electrostatic attraction of protofilaments is only slightly stronger than these weak amphiphilic interactions. The potential biological relevance of the deposition of such a highly anisotropic biomaterial in vivo is discussed.

  3. Preventing Data Ambiguity in Infectious Diseases with Four-Dimensional and Personalized Evaluations.

    Directory of Open Access Journals (Sweden)

    Michelle J Iandiorio

    Full Text Available Diagnostic errors can occur, in infectious diseases, when anti-microbial immune responses involve several temporal scales. When responses span from nanosecond to week and larger temporal scales, any pre-selected temporal scale is likely to miss some (faster or slower responses. Hoping to prevent diagnostic errors, a pilot study was conducted to evaluate a four-dimensional (4D method that captures the complexity and dynamics of infectious diseases.Leukocyte-microbial-temporal data were explored in canine and human (bacterial and/or viral infections, with: (i a non-structured approach, which measures leukocytes or microbes in isolation; and (ii a structured method that assesses numerous combinations of interacting variables. Four alternatives of the structured method were tested: (i a noise-reduction oriented version, which generates a single (one data point-wide line of observations; (ii a version that measures complex, three-dimensional (3D data interactions; (iii a non-numerical version that displays temporal data directionality (arrows that connect pairs of consecutive observations; and (iv a full 4D (single line-, complexity-, directionality-based version.In all studies, the non-structured approach revealed non-interpretable (ambiguous data: observations numerically similar expressed different biological conditions, such as recovery and lack of recovery from infections. Ambiguity was also found when the data were structured as single lines. In contrast, two or more data subsets were distinguished and ambiguity was avoided when the data were structured as complex, 3D, single lines and, in addition, temporal data directionality was determined. The 4D method detected, even within one day, changes in immune profiles that occurred after antibiotics were prescribed.Infectious disease data may be ambiguous. Four-dimensional methods may prevent ambiguity, providing earlier, in vivo, dynamic, complex, and personalized information that facilitates both

  4. Toward four-dimensional image-guided adaptive brachytherapy in locally recurrent endometrial cancer.

    Science.gov (United States)

    Fokdal, Lars; Ørtoft, Gitte; Hansen, Estrid S; Røhl, Lisbeth; Pedersen, Erik Morre; Tanderup, Kari; Lindegaard, Jacob Christian

    2014-01-01

    To evaluate clinical outcome and feasibility of a four-dimensional image-guided adaptive brachytherapy concept in patients with locally recurrent endometrial cancer. Forty-three patients with locally recurrent endometrial cancer were included. Treatment consisted of conformal external beam radiotherapy followed by a boost using pulsed-dose-rate brachytherapy (BT). Large tumors were treated with MRI-guided interstitial BT. Small tumors were treated with CT-guided intracavitary BT. The planning aim (total external beam radiotherapy and BT) for high-risk clinical target volume was D90 > 80 Gy, whereas constraints for organs at risk were D2cc ≤ 90 Gy for bladder and D2cc ≤ 70 Gy for rectum, sigmoid, and bowel in terms of equivalent dose in 2 Gy fractions. Median high-risk clinical target volume was 18 cm(3) (range, 0-91). D90 was 82 Gy (range, 77-88). D2cc to bladder, rectum, and sigmoid were 67 Gy (range, 50-81), 67 Gy (range, 51-77), and 55 Gy (range, 44-68), respectively. Median followup was 30 months (6-88). Two-year local control rate was 92% (standard error [SE], 5). Disease-free survival rate and overall survival rate was 59% (SE, 8) and 78% (SE, 7), respectively. Patients with low- to intermediate-risk for recurrence had a 2-year disease-free survival rate of 72% (SE, 9) compared with 42% (SE, 12) in patients with high risk for recurrence (p = 0.04). Late morbidity Grade 3 was recorded in 5 (12%) patients. Four-dimensional image-guided adaptive brachytherapy is feasible in locally recurrent endometrial cancer. Local control rate is good. Systemic control remains a problem in patients with high risk for recurrence. Copyright © 2014 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  5. Spatial heterogeneity of four-dimensional relative pressure fields in the human left ventricle.

    Science.gov (United States)

    Eriksson, Jonatan; Bolger, Ann F; Carlhäll, Carl-Johan; Ebbers, Tino

    2015-12-01

    To assess the spatial heterogeneity of the four-dimensional (4D) relative pressure fields in the healthy human left ventricle (LV) and provide reference data for normal LV relative pressure. Twelve healthy subjects underwent a cardiac MRI examination where 4D flow and morphological data were acquired. The latter data were segmented and used to define the borders of the LV for computation of relative pressure fields using the pressure Poisson equation. The LV lumen was divided into 17 pie-shaped segments. In the normal left ventricle, the relative pressure in the apical segments was significantly higher relative to the basal segments (P pressure than the opposite basal inferolateral segment during both E-wave (P Relative pressure in the left ventricle is heterogeneous. During diastole, the main pressure differences in the LV occur along the basal-apical axis. However, pressure differences were also found in the short axis direction and may reflect important aspects of atrioventricular coupling. Additionally, this study provides reference data on LV pressure dynamics for a group of healthy subjects. © 2014 Wiley Periodicals, Inc.

  6. Four-dimensional address topology for circuits with stacked multilayer crossbar arrays.

    Science.gov (United States)

    Strukov, Dmitri B; Williams, R Stanley

    2009-12-01

    We present a topological framework that provides a simple yet powerful electronic circuit architecture for constructing and using multilayer crossbar arrays, allowing a significantly increased integration density of memristive crosspoint devices beyond the scaling limits of lateral feature sizes. The truly remarkable feature of such circuits, which is an extension of the CMOL (Cmos + MOLecular-scale devices) concept for an area-like interface to a three-dimensional system, is that a large-feature-size complimentary metal-oxide-semiconductor (CMOS) substrate can provide high-density interconnects to multiple crossbar layers through a single set of vertical vias. The physical locations of the memristive devices are mapped to a four-dimensional logical address space such that unique access from the CMOS substrate is provided to every device in a stacked array of crossbars. This hybrid architecture is compatible with digital memories, field-programmable gate arrays, and biologically inspired adaptive networks and with state-of-the-art integrated circuit foundries.

  7. Four-dimensional IMRT treatment planning using a DMLC motion-tracking algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Yelin [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA (United States); Sawant, Amit; Venkat, Raghu; Keall, Paul J [Department of Radiation Oncology, Stanford University, 875 Black Wilbur Drive, Stanford, CA 94305-5847 (United States)], E-mail: ysuh@stanford.edu

    2009-06-21

    The purpose of this study is to develop a four-dimensional (4D) intensity-modulated radiation therapy (IMRT) treatment-planning method by modifying and applying a dynamic multileaf collimator (DMLC) motion-tracking algorithm. The 4D radiotherapy treatment scenario investigated is to obtain a 4D treatment plan based on a 4D computed tomography (CT) planning scan and to have the delivery flexible enough to account for changes in tumor position during treatment delivery. For each of 4D CT planning scans from 12 lung cancer patients, a reference phase plan was created; with its MLC leaf positions and three-dimensional (3D) tumor motion, the DMLC motion-tracking algorithm generated MLC leaf sequences for the plans of other respiratory phases. Then, a deformable dose-summed 4D plan was created by merging the leaf sequences of individual phase plans. Individual phase plans, as well as the deformable dose-summed 4D plan, are similar for each patient, indicating that this method is dosimetrically robust to the variations of fractional time spent in respiratory phases on a given 4D CT planning scan. The 4D IMRT treatment-planning method utilizing the DMLC motion-tracking algorithm explicitly accounts for 3D tumor motion and thus hysteresis and nonlinear motion, and is deliverable on a linear accelerator.

  8. Four-Dimensional Ultrafast Electron Microscopy: Insights into an Emerging Technique

    KAUST Repository

    Adhikari, Aniruddha

    2016-12-15

    Four-dimensional ultrafast electron microscopy (4D-UEM) is a novel analytical technique that aims to fulfill the long-held dream of researchers to investigate materials at extremely short spatial and temporal resolutions by integrating the excellent spatial resolution of electron microscopes with the temporal resolution of ultrafast femtosecond laser-based spectroscopy. The ingenious use of pulsed photoelectrons to probe surfaces and volumes of materials enables time-resolved snapshots of the dynamics to be captured in a way hitherto impossible by other conventional techniques. The flexibility of 4D-UEM lies in the fact that it can be used in both the scanning (S-UEM) and transmission (UEM) modes depending upon the type of electron microscope involved. While UEM can be employed to monitor elementary structural changes and phase transitions in samples using real-space mapping, diffraction, electron energy-loss spectroscopy, and tomography, S-UEM is well suited to map ultrafast dynamical events on materials surfaces in space and time. This review provides an overview of the unique features that distinguish these techniques and also illustrates the applications of both S-UEM and UEM to a multitude of problems relevant to materials science and chemistry.

  9. Four-dimensional reconstruction of cultural heritage sites based on photogrammetry and clustering

    Science.gov (United States)

    Voulodimos, Athanasios; Doulamis, Nikolaos; Fritsch, Dieter; Makantasis, Konstantinos; Doulamis, Anastasios; Klein, Michael

    2017-01-01

    A system designed and developed for the three-dimensional (3-D) reconstruction of cultural heritage (CH) assets is presented. Two basic approaches are presented. The first one, resulting in an "approximate" 3-D model, uses images retrieved in online multimedia collections; it employs a clustering-based technique to perform content-based filtering and eliminate outliers that significantly reduce the performance of 3-D reconstruction frameworks. The second one is based on input image data acquired through terrestrial laser scanning, as well as close range and airborne photogrammetry; it follows a sophisticated multistep strategy, which leads to a "precise" 3-D model. Furthermore, the concept of change history maps is proposed to address the computational limitations involved in four-dimensional (4-D) modeling, i.e., capturing 3-D models of a CH landmark or site at different time instances. The system also comprises a presentation viewer, which manages the display of the multifaceted CH content collected and created. The described methods have been successfully applied and evaluated in challenging real-world scenarios, including the 4-D reconstruction of the historic Market Square of the German city of Calw in the context of the 4-D-CH-World EU project.

  10. Almost conformal transformation in a four dimensional Riemannian manifold with an additional structure

    CERN Document Server

    Dokuzova, Iva

    2011-01-01

    We consider a four dimensional Riemannian manifold M with a metric g and affinor structure q. The local coordinates of these tensors are circulant matrices. Their first orders are (A, B, C, B), A, B, C\\in FM and (0, 1, 0, 0), respectively. We construct another metric \\tilde{g} on M. We find the conditions for \\tilde{g} to be a positively defined metric, and for q to be a parallel structure with respect to the Riemannian connection of g. Further, let x be an arbitrary vector in T_{p}M, where p is a point on M. Let \\phi and \\phi be the angles between x and qx, x and q^{2}x with respect to g. We express the angles between x and qx, x and q^{2}x with respect to $\\tilde{g}$ with the help of the angles $\\phi$ and \\phi. Also,we construct two series {\\phi_{n}}and {\\phi_{n}}. We prove that every of it is an increasing one and it is converge.

  11. Coupling Ensemble Kalman Filter with Four-dimensional Variational Data Assimilation

    Institute of Scientific and Technical Information of China (English)

    Fuqing ZHANG; Meng ZHANG; James A. HANSEN

    2009-01-01

    This study examines the performance of coupling the deterministic four-dimensional variational assimilation system (4DVAR) with an ensemble Kalman filter (EnKF) to produce a superior hybrid approach for data assimilation. The coupled assimilation scheme (E4DVAR) benefits from using the state-dependent uncertainty provided by EnKF while taking advantage of 4DVAR in preventing filter divergence: the 4DVAR analysis produces posterior maximum likelihood solutions through minimization of a cost function about which the ensemble perturbations are transformed, and the resulting ensemble analysis can be propagated forward both for the next assimilation cycle and as a basis for ensemble forecasting. The feasibility and effectiveness of this coupled approach are demonstrated in an idealized model with simulated observations. It is found that the E4DVAR is capable of outperforming both 4DVAR and the EnKF under both perfect-and imperfect-model scenarios. The performance of the coupled scheme is also less sensitive to either the ensemble size or the assimilation window length than those for standard EnKF or 4DVAR implementations.

  12. Combining four dimensional variational data assimilation and particle filtering for estimating volcanic ash emissions

    Science.gov (United States)

    Franke, Philipp; Elbern, Hendrik

    2016-04-01

    Estimating volcanic ash emissions is a very challenging task due to limited monitoring capacities of the ash plume and nonlinear processes in the atmosphere, which renders application of source strength and injection height estimations difficult. Most models, which estimate volcanic ash emissions, make strong simplifications of the dispersion of volcanic ash and corresponding atmospheric processes. The objective of this work is to estimate volcanic ash emissions and simulate the ensuing dispersion applying a full chemistry transport model in a hybrid approach by using its adjoint as well as an ensemble of model runs to quantify forecast uncertainties. Therefore, the four dimensional variational data assimilation version of the EURAD-IM chemistry transport model is extended to include a Sequential Importance Resampling Smoother (SIRS), introducing novel weighting and resampling strategies. In the main SIRS step the ensemble members exchange high rated emission patterns while rejecting emission patterns with low value for the forecast. The emission profiles of the ensemble members are perturbed afterwards to guarantee different emissions for all ensemble members. First identical twin experiments show the ability of the system to estimate the temporal and vertical distribution of volcanic ash emissions. The 4D-var data assimilation algorithm of the new system additionally provides quantitative emission estimation.

  13. Four-Dimensional Ultrafast Electron Microscopy: Insights into an Emerging Technique.

    Science.gov (United States)

    Adhikari, Aniruddha; Eliason, Jeffrey K; Sun, Jingya; Bose, Riya; Flannigan, David J; Mohammed, Omar F

    2017-01-11

    Four-dimensional ultrafast electron microscopy (4D-UEM) is a novel analytical technique that aims to fulfill the long-held dream of researchers to investigate materials at extremely short spatial and temporal resolutions by integrating the excellent spatial resolution of electron microscopes with the temporal resolution of ultrafast femtosecond laser-based spectroscopy. The ingenious use of pulsed photoelectrons to probe surfaces and volumes of materials enables time-resolved snapshots of the dynamics to be captured in a way hitherto impossible by other conventional techniques. The flexibility of 4D-UEM lies in the fact that it can be used in both the scanning (S-UEM) and transmission (UEM) modes depending upon the type of electron microscope involved. While UEM can be employed to monitor elementary structural changes and phase transitions in samples using real-space mapping, diffraction, electron energy-loss spectroscopy, and tomography, S-UEM is well suited to map ultrafast dynamical events on materials surfaces in space and time. This review provides an overview of the unique features that distinguish these techniques and also illustrates the applications of both S-UEM and UEM to a multitude of problems relevant to materials science and chemistry.

  14. A four-dimensional virtual hand brain-machine interface using active dimension selection

    Science.gov (United States)

    Rouse, Adam G.

    2016-06-01

    Objective. Brain-machine interfaces (BMI) traditionally rely on a fixed, linear transformation from neural signals to an output state-space. In this study, the assumption that a BMI must control a fixed, orthogonal basis set was challenged and a novel active dimension selection (ADS) decoder was explored. Approach. ADS utilizes a two stage decoder by using neural signals to both (i) select an active dimension being controlled and (ii) control the velocity along the selected dimension. ADS decoding was tested in a monkey using 16 single units from premotor and primary motor cortex to successfully control a virtual hand avatar to move to eight different postures. Main results. Following training with the ADS decoder to control 2, 3, and then 4 dimensions, each emulating a grasp shape of the hand, performance reached 93% correct with a bit rate of 2.4 bits s-1 for eight targets. Selection of eight targets using ADS control was more efficient, as measured by bit rate, than either full four-dimensional control or computer assisted one-dimensional control. Significance. ADS decoding allows a user to quickly and efficiently select different hand postures. This novel decoding scheme represents a potential method to reduce the complexity of high-dimension BMI control of the hand.

  15. NOTE: Conceptual formulation on four-dimensional inverse planning for intensity modulated radiation therapy

    Science.gov (United States)

    Lee, Louis; Ma, Yunzhi; Ye, Yinyu; Xing, Lei

    2009-07-01

    Four-dimensional computed tomography (4DCT) offers an extra dimension of 'time' on the three-dimensional patient model with which we can incorporate target motion in radiation treatment (RT) planning and delivery in various ways such as in the concept of internal target volume, in gated treatment or in target tracking. However, for all these methodologies, different phases are essentially considered as non-interconnected independent phases for the purpose of optimization, in other words, the 'time' dimension has yet to be incorporated explicitly in the optimization algorithm and fully exploited. In this note, we have formulated a new 4D inverse planning technique that treats all the phases in the 4DCT as one single entity in the optimization. The optimization is formulated as a quadratic problem for disciplined convex programming that enables the problem to be analyzed and solved efficiently. In the proof-of-principle examples illustrated, we show that the temporal information of the spatial relation of the target and organs at risk could be 'exchanged' amongst different phases so that an appropriate weighting of dose deposition could be allocated to each phase, thus enabling a treatment with a tight target margin and a full duty cycle otherwise not achievable by either of the aforementioned methodologies. Yet there are practical issues to be solved in the 4D RT planning and delivery. The 4D concept in the optimization we have formulated here does provide insight on how the 'time' dimension can be exploited in the 4D optimization process.

  16. Four-dimensional measurement by a single-frame structured light method.

    Science.gov (United States)

    Sitnik, Robert

    2009-06-20

    A four-dimensional [4D--three-dimensional (3D) shape varying in time] shape measurement system is described. A single 3D shape of an object is calculated from only one frame. The projected pattern is composed of sinusoidal intensity fringes and one color-encoded stripe, the analysis of which allows us to find the absolute coordinates of the measured object. During measurement, the position of the stripe changes due to the improvement of the quality of spatiotemporal unwrapping. The fringes deformed by the shape of the object are captured by a CCD camera and processed by an adaptive spatial carrier phase-shifting algorithm. The use of an algorithm based on fast Fourier transformation is proposed to approximate the local period of fringes. A new phase-unwrapping routine based on the spatiotemporal information is presented as well. All these features make the 3D shape measurement of an object in motion possible with the additional advantage of using a low-cost system. Experimental results of the developed method together with a preliminary assessment of measurement uncertainty are presented to show the validity of the method.

  17. Quantum Mechanics and Black Holes in Four-Dimensional String Theory

    CERN Document Server

    Ellis, Jonathan Richard; Nanopoulos, Dimitri V

    1992-01-01

    In previous papers we have shown how strings in a two-dimensional target space reconcile quantum mechanics with general relativity, thanks to an infinite set of conserved quantum numbers, ``W-hair'', associated with topological soliton-like states. In this paper we extend these arguments to four dimensions, by considering explicitly the case of string black holes with radial symmetry. The key infinite-dimensional W-symmetry is associated with the $\\frac{SU(1,1)}{U(1)}$ coset structure of the dilaton-graviton sector that is a model-independent feature of spherically symmetric four-dimensional strings. Arguments are also given that the enormous number of string {\\it discrete (topological)} states account for the maintenance of quantum coherence during the (non-thermal) stringy evaporation process, as well as quenching the large Hawking-Bekenstein entropy associated with the black hole. Defining the latter as the measure of the loss of information for an observer at infinity, who - ignoring the higher string qua...

  18. Four-dimensional model of the lower extremity after total hip arthroplasty.

    Science.gov (United States)

    Otake, Yoshito; Suzuki, Naoki; Hattori, Asaki; Hagio, Keisuke; Sugano, Nobuhiko; Yonenobu, Kazuo; Ochi, Takahiro

    2005-12-01

    We have developed a four-dimensional (4D) model of the lower extremities after total hip arthroplasty in patients. The model can aid in preventing complications such as dislocation and wearing of the sliding surface. The skeletal structure and implant alignment were obtained from CT data. We applied registration method using CAD data to estimate accurate implant alignment from scattered CT data. The reconstructed three-dimensional (3D) skeletal model was combined with motion capture data that were acquired by an optical tracking system. We displayed the patient's skeletal movement and analyzed several parameters that relate to complications. The patient's skeletal model was superimposed onto video footage that was taken by a synchronized and calibrated digital video camera. For validation of the measurement error in this system, we used open MRI to evaluate the relative movement between skin markers and bones. This system visually represents not only the 3D anatomical structure, but also 4D dynamic functions that include the time sequential transitions of components and their positions. The open MRI results indicated that the average error in hip angle was within 5 degrees for each static posture. This system enables clinicians to analyze patient's motions on the basis of individual differences. We found that our system was an effective tool in providing precise guidance of daily postoperative motions that was individualized for each patient. This system will be applicable for surgical planning, assessment of postoperative activities, and the development of new surgical techniques, materials, and prosthetic designs.

  19. Four-Dimensional Coded Modulation with Bit-wise Decoders for Future Optical Communications

    CERN Document Server

    Alvarado, Alex

    2014-01-01

    Coded modulation (CM) is the combination of forward error correction (FEC) and multilevel constellations. Coherent optical communication systems result in a four-dimensional (4D) signal space, which naturally leads to 4D-CM transceivers. A practically attractive design paradigm is to use a bit-wise decoder, where the detection process is (suboptimally) separated into two steps: soft-decision demapping followed by binary decoding. In this paper, bit-wise decoders are studied from an information-theoretic viewpoint. 4D constellations with up to 4096 constellation points are considered. Metrics to predict the post-FEC bit-error rate (BER) of bit-wise decoders are analyzed. The mutual information is shown to fail at predicting the post-FEC BER of bit-wise decoders and the so-called generalized mutual information is shown to be a much more robust metric. It is also shown that constellations that transmit and receive information in each polarization and quadrature independently (e.g., PM-QPSK, PM-16QAM, and PM-64QA...

  20. Estimate of the Critical Exponent of the Anderson Transition in the Three and Four-Dimensional Unitary Universality Classes

    Science.gov (United States)

    Slevin, Keith; Ohtsuki, Tomi

    2016-10-01

    Disordered non-interacting systems are classified into ten symmetry classes, with the unitary class being the most fundamental. The three and four-dimensional unitary universality classes are attracting renewed interest because of their relation to three-dimensional Weyl semi-metals and four-dimensional topological insulators. Determining the critical exponent of the correlation/localisation length for the Anderson transition in these classes is important both theoretically and experimentally. Using the transfer matrix technique, we report numerical estimations of the critical exponent in a U(1) model in three and four dimensions.

  1. [Stress echocardiography: development and significance].

    Science.gov (United States)

    Attenhofer, C; Ritter, M; Jenni, R

    1994-08-27

    Exercise electrocardiography is still the primary method used in the non-invasive assessment of coronary artery disease. Stress echocardiography is now being increasingly used as a more sensitive adjunct technique to assess ischemia. Ischemia provoked by stress can induce reversible wall motion abnormalities which are disclosed by cross-sectional 2-dimensional echocardiography and standard projections. The types of stress used are physical exercise (bicycle, treadmill), atrial pacing or pharmacologic stimulation. In the latter, the catecholamine dobutamine has emerged as preferable to the vasodilators dipyridamole and adenosine. The diagnostic accuracy of dobutamine stress echocardiography is comparable to that of bicycle or treadmill exercise echocardiography, but dobutamine stress echocardiography is technically simpler and can be performed in patients unable to exercise. Its sensitivity in diagnosing ischemic or viable myocardium is comparable to that of nuclear methods, MRI or PET. In contrast to nuclear methods, stress echocardiography is however free of radiation. In the assessment of patients with coronary artery disease, stress echocardiography has been shown to be valuable for diagnosis, preoperative risk stratification and determination of prognosis. Furthermore, low dose dobutamine echocardiography can be used to detect viable myocardium. Despite these very promising aspects of the method, there are recognized disadvantages and limitations: stress echocardiography is very time-consuming and operator-dependent; its sensitivity correlates strongly with the number of studies performed; analysis of wall motion is performed qualitatively on a purely subjective level, and hence lacks the objectivity of a quantitative approach. These factors emphasize the need for intensive research to render stress echocardiographic analysis more objective. Automatic boundary detection of left ventricular endocardium, color-Doppler-based tissue imaging and three

  2. An automated method for comparing motion artifacts in cine four-dimensional computed tomography images.

    Science.gov (United States)

    Cui, Guoqiang; Jew, Brian; Hong, Julian C; Johnston, Eric W; Loo, Billy W; Maxim, Peter G

    2012-11-08

    The aim of this study is to develop an automated method to objectively compare motion artifacts in two four-dimensional computed tomography (4D CT) image sets, and identify the one that would appear to human observers with fewer or smaller artifacts. Our proposed method is based on the difference of the normalized correlation coefficients between edge slices at couch transitions, which we hypothesize may be a suitable metric to identify motion artifacts. We evaluated our method using ten pairs of 4D CT image sets that showed subtle differences in artifacts between images in a pair, which were identifiable by human observers. One set of 4D CT images was sorted using breathing traces in which our clinically implemented 4D CT sorting software miscalculated the respiratory phase, which expectedly led to artifacts in the images. The other set of images consisted of the same images; however, these were sorted using the same breathing traces but with corrected phases. Next we calculated the normalized correlation coefficients between edge slices at all couch transitions for all respiratory phases in both image sets to evaluate for motion artifacts. For nine image set pairs, our method identified the 4D CT sets sorted using the breathing traces with the corrected respiratory phase to result in images with fewer or smaller artifacts, whereas for one image pair, no difference was noted. Two observers independently assessed the accuracy of our method. Both observers identified 9 image sets that were sorted using the breathing traces with corrected respiratory phase as having fewer or smaller artifacts. In summary, using the 4D CT data of ten pairs of 4D CT image sets, we have demonstrated proof of principle that our method is able to replicate the results of two human observers in identifying the image set with fewer or smaller artifacts.

  3. Novel Assessment of Renal Motion in Children as Measured via Four-Dimensional Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Pai Panandiker, Atmaram S., E-mail: atmaram.pai-panandiker@stjude.org [Department of Radiological Sciences, St. Jude Children' s Research Hospital, Memphis, TN (United States); Sharma, Shelly; Naik, Mihir H. [Department of Radiological Sciences, St. Jude Children' s Research Hospital, Memphis, TN (United States); Wu, Shengjie [Department of Biostatistics, St. Jude Children' s Research Hospital, Memphis, TN (United States); Hua, Chiaho; Beltran, Chris; Krasin, Matthew J.; Merchant, Thomas E. [Department of Radiological Sciences, St. Jude Children' s Research Hospital, Memphis, TN (United States)

    2012-04-01

    Objectives: Abdominal intensity-modulated radiation therapy and proton therapy require quantification of target and organ motion to optimize localization and treatment. Although addressed in adults, there is no available literature on this issue in pediatric patients. We assessed physiologic renal motion in pediatric patients. Methods and Materials: Twenty free-breathing pediatric patients at a median age of 8 years (range, 2-18 years) with intra-abdominal tumors underwent computed tomography simulation and four-dimensional computed tomography acquisition (slice thickness, 3 mm). Kidneys and diaphragms were contoured during eight phases of respiration to estimate center-of-mass motion. We quantified center of kidney mass mobility vectors in three dimensions: anteroposterior (AP), mediolateral (ML), and superoinferior (SI). Results: Kidney motion decreases linearly with decreasing age and height. The 95% confidence interval for the averaged minima and maxima of renal motion in children younger than 9 years was 5-9 mm in the ML direction, 4-11 mm in the AP direction, and 12-25 mm in the SI dimension for both kidneys. In children older than 9 years, the same confidence interval reveals a widening range of motion that was 5-16 mm in the ML direction, 6-17 mm in the AP direction, and 21-52 mm in the SI direction. Although not statistically significant, renal motion correlated with diaphragm motion in older patients. The correlation between diaphragm motion and body mass index was borderline (r = 0.52, p = 0.0816) in younger patients. Conclusions: Renal motion is age and height dependent. Measuring diaphragmatic motion alone does not reliably quantify pediatric renal motion. Renal motion in young children ranges from 5 to 25 mm in orientation-specific directions. The vectors of motion range from 5 to 52 mm in older children. These preliminary data represent novel analyses of pediatric intra-abdominal organ motion.

  4. A New Global Four-Dimensional Variational Ocean Data Assimilation System and Its Application

    Institute of Scientific and Technical Information of China (English)

    LIU Juan; WANG Bin; LIU Hailong; YU Yongqiang

    2008-01-01

    A four-dimensional variational data assimilation (4DVar) system of the LASG/IAP Climate Ocean Model, version 1.0 (LICOM1.0), named LICOM-3DVM, has been developed using the three-dimensional variational data assimilation of mapped observation (3DVM), a 4DVar method newly proposed in the past two years. Two experiments with 12-year model integrations were designed to validate it. One is the as- similation run, called ASSM, which incorporated the analyzed weekly sea surface temperature (SST) fields from Reynolds and Smith (OISST) between 1990 and 2001 once a week by the LICOM-3DVM. The other is the control run without any assimilation, named CTL. ASSM shows that the simulated temperatures of the upper ocean (above 50 meters), especially the SST of equatorial Pacific, coincide with the Tropic Atmo- sphere Ocean (TAO) mooring data, the World Ocean Atlas 2001 (WOA01) data and the Met Office Hadley Centre's sea ice and sea surface temperature (HadISST) data. It decreased the cold bias existing in CTL in the eastern Pacific and produced a Nino index that agrees with observation well. The validation results suggest that the LICOM-3DVM is able to effectively adjust the model results of the ocean temperature, although it's hard to correct the subsurface results and it even makes them worse in some areas due to the incorporation of only surface data. Future development of the LICOM-3DVM is to include subsurface in situ observations and satellite observations to further improve model simulations.

  5. Four-Dimensional Printing Hierarchy Scaffolds with Highly Biocompatible Smart Polymers for Tissue Engineering Applications.

    Science.gov (United States)

    Miao, Shida; Zhu, Wei; Castro, Nathan J; Leng, Jinsong; Zhang, Lijie Grace

    2016-10-01

    The objective of this study was to four-dimensional (4D) print novel biomimetic gradient tissue scaffolds with highly biocompatible naturally derived smart polymers. The term "4D printing" refers to the inherent smart shape transformation of fabricated constructs when implanted minimally invasively for seamless and dynamic integration. For this purpose, a series of novel shape memory polymers with excellent biocompatibility and tunable shape changing effects were synthesized and cured in the presence of three-dimensional printed sacrificial molds, which were subsequently dissolved to create controllable and graded porosity within the scaffold. Surface morphology, thermal, mechanical, and biocompatible properties as well as shape memory effects of the synthesized smart polymers and resultant porous scaffolds were characterized. Fourier transform infrared spectroscopy and gel content analysis confirmed the formation of chemical crosslinking by reacting polycaprolactone triol and castor oil with multi-isocyanate groups. Differential scanning calorimetry revealed an adjustable glass transition temperature in a range from -8°C to 35°C. Uniaxial compression testing indicated that the obtained polymers, possessing a highly crosslinked interpenetrating polymeric networks, have similar compressive modulus to polycaprolactone. Shape memory tests revealed that the smart polymers display finely tunable recovery speed and exhibit greater than 92% shape fixing at -18°C or 0°C and full shape recovery at physiological temperature. Scanning electron microscopy analysis of fabricated scaffolds revealed a graded microporous structure, which mimics the nonuniform distribution of porosity found within natural tissues. With polycaprolactone serving as a control, human bone marrow-derived mesenchymal stem cell adhesion, proliferation, and differentiation greatly increased on our novel smart polymers. The current work will significantly advance the future design and development of

  6. A novel system of four-dimensional motion analysis after total hip arthroplasty.

    Science.gov (United States)

    Hagio, Keisuke; Sugano, Nobuhiko; Nishii, Takashi; Miki, Hidenobu; Otake, Yoshito; Hattori, Asaki; Suzuki, Naoki; Yonenobu, Kazuo; Yoshikawa, Hideki; Ochi, Takahiro

    2004-05-01

    We have developed a novel system of four-dimensional motion analysis after total hip arthroplasty (THA) that can aid in preventing dislocation by assessing safe range of motion for patients in several daily activities. This system uses skeletal structure data from CT and motion capture data from an infrared position sensor. A 3-D model reconstructed from CT data is combined with the motion capture data. Using this system, we analyzed hip motion when getting up from and sitting down in a chair or picking up an object while sitting in a chair in 17 patients (26 hips) who underwent THA. To assess the accuracy of this system's measurements, open MRI was used to evaluate positions of skin markers against bones in five healthy volunteers in various postures. No impingement between bones and/or implants was found in any subjects during any activities. However, mean angle at the point of maximum hip flexion was different for each patient. The open MRI results indicated that average error in hip angle of the present system was within 5 degrees for each static posture. The functional position of the pelvis during daily activities must be taken into account when assessing the real risk of dislocation. The present system enables dynamic analysis involving not only alignment of components and bones of each patient, but also individual differences in characteristics of daily motions. Further investigation using this system can help determine safe ranges of motion for preventing hip dislocation, improving the accuracy of individualized guidance for patients regarding postoperative activities.

  7. Impact of four-dimensional data assimilation (FDDA) on urban climate analysis

    Science.gov (United States)

    Pan, Linlin; Liu, Yubao; Liu, Yuewei; Li, Lei; Jiang, Yin; Cheng, Will; Roux, Gregory

    2015-12-01

    This study investigates the impact of four-dimensional data assimilation (FDDA) on urban climate analysis, which employs the NCAR (National Center for Atmospheric Research) WRF (the weather research and forecasting model) based on climate FDDA (CFDDA) technology to develop an urban-scale microclimatology database for the Shenzhen area, a rapidly developing metropolitan located along the southern coast of China, where uniquely high-density observations, including ultrahigh-resolution surface AWS (automatic weather station) network, radio sounding, wind profilers, radiometers, and other weather observation platforms, have been installed. CFDDA is an innovative dynamical downscaling regional climate analysis system that assimilates diverse regional observations; and has been employed to produce a 5 year multiscale high-resolution microclimate analysis by assimilating high-density observations at Shenzhen area. The CFDDA system was configured with four nested-grid domains at grid sizes of 27, 9, 3, and 1 km, respectively. This research evaluates the impact of assimilating high-resolution observation data on reproducing the refining features of urban-scale circulations. Two experiments were conducted with a 5 year run using CFSR (climate forecast system reanalysis) as boundary and initial conditions: one with CFDDA and the other without. The comparisons of these two experiments with observations indicate that CFDDA greatly reduces the model analysis error and is able to realistically analyze the microscale features such as urban-rural-coastal circulation, land/sea breezes, and local-hilly terrain thermal circulations. It is demonstrated that the urbanization can produce 2.5 k differences in 2 m temperatures, delays/speeds up the land/sea breeze development, and interacts with local mountain-valley circulations.

  8. Pacing stress echocardiography

    Directory of Open Access Journals (Sweden)

    Agrusta Marco

    2005-12-01

    Full Text Available Abstract Background High-rate pacing is a valid stress test to be used in conjunction with echocardiography; it is independent of physical exercise and does not require drug administration. There are two main applications of pacing stress in the echo lab: the noninvasive detection of coronary artery disease through induction of a regional transient dysfunction; and the assessment of contractile reserve through peak systolic pressure/ end-systolic volume relationship at increasing heart rates to assess global left ventricular contractility. Methods The pathophysiologic rationale of pacing stress for noninvasive detection of coronary artery disease is obvious, with the stress determined by a controlled increase in heart rate, which is a major determinant of myocardial oxygen demand, and thereby tachycardia may exceed a fixed coronary flow reserve in the presence of hemodynamically significant coronary artery disease. The use of pacing stress echo to assess left ventricular contractile reserve is less established, but promising. Positive inotropic interventions are mirrored by smaller end-systolic volumes and higher end-systolic pressures. An increased heart rate progressively increases the force of ventricular contraction (Bowditch treppe or staircase phenomenon. To build the force-frequency relationship, the force is determined at different heart rate steps as the ratio of the systolic pressure (cuff sphygmomanometer/end-systolic volume index (biplane Simpson rule. The heart rate is determined from ECG. Conclusion Two-dimensional echocardiography during pacing is a useful tool in the detection of coronary artery disease. Because of its safety and ease of repeatability noninvasive pacing stress echo can be the first-line stress test in patients with permanent pacemaker. The force-frequency can be defined as up- sloping (normal when the peak stress pacing systolic pressure/end-systolic volume index is higher than baseline and intermediate stress

  9. Do Human Fetuses Anticipate Self-Oriented Actions? A Study by Four-Dimensional (4D) Ultrasonography

    Science.gov (United States)

    Myowa-Yamakoshi, Masako; Takeshita, Hideko

    2006-01-01

    Using four-dimensional (4D) ultrasonography, arm and hand movements toward the face were examined in 27 human fetuses at 19 to 35 weeks of gestation, thereby enabling the continuous monitoring of their faces and other surface features such as the extremities. More than half of the observed arm movements resulted in the hand touching the mouth…

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

    Science.gov (United States)

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

    2017-01-01

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

  11. Four dimensional variational data assimilation of species-resolved satellite-retrieved aerosol optical thickness

    Science.gov (United States)

    Nieradzik, Lars Peter; Elbern, Hendrik

    2010-05-01

    Aerosols play an increasingly important role in atmospheric modelling. They have a strong influence on the radiative transfer balance and a significant impact on human health. Their origin is various and so are its effects. Most of the measurement sites in Europe only account for an integrated aerosol load PMx (Particulate Matter of less than x μm in diameter) which does not give any qualitative information on the composition of the aerosol. Since very different constituents like mineral dust derived from desert storms and sea salt contribute to PMx it is necessary to make aerosol forcasts not only of load, but also type resolved. The source of information chosen for this study is the aerosol retrieval system SYNAER (SYNergetic AErosol Retrieval) from DLR-DFD that retrieves BLAOT (Boundary Layer Aerosol Optical Thickness) making use of both AATSR/SCIAMACHY and AVHRR/GOME-2 data respectively. Its strengths are a large spatial coverage, near real-time availability, and the classification of five intrinsic aerosol species, namely water-solubles, water-insolubles, soot, sea salt, and mineral dust which are furthermore size resolved in terms of modes. A widely known technique to enhance forecast skills of CTMs (Chemistry-Transport-Models) by ingesting in-situ and, especially, remote-sensing measurements is the method of four dimensional variational data assimilation (4Dvar). The EURAD-IM (EURopean Air pollution Dispersion - Inverse Model), containing a full adjoint gas-phase model, has been expanded with an adjoint of the MADE (Modal Aerosol Dynamics model for Europe) to optimise initial and boundary values for aerosols using 4Dvar. A forward and an adjoint radiative transfer model is driven by the EURAD-IM as mapping between BLAOT and internal aerosol species. Furthermore, its condensation scheme has been bypassed by an HDMR (High-Dimensional-Model-Representation) to ensure differentiability, and a time saving online NMC-module for the generation of the background

  12. Four dimensional variational assimilation of in-situ and remote-sensing aerosol data

    Science.gov (United States)

    Nieradzik, L. P.; Elbern, H.

    2012-04-01

    Aerosols play an increasingly important role in atmospheric modelling. They have a strong influence on the radiative transfer balance and a significant impact on human health. Their origin is various and so are its effects. Most of the measurement sites in Europe account for an integrated aerosol load PMx (Particulate Matter of less than x μm in diameter) which does not give any qualitative information on the composition of the aerosol. Since very different constituents contribute to PMx, like e.g. mineral dust derived from desert storms or sea salt, it is necessary to make aerosol forecasts not only of load, but also type resolved. The method of four dimensional variational data assimilation (4Dvar) is a widely known technique to enhance forecast skills of CTMs (Chemistry-Transport-Models) by ingesting in-situ and, especially, remote-sensing measurements. The EURAD-IM (EURopean Air pollution Dispersion - Inverse Model), containing a full adjoint gas-phase model, has been expanded with an adjoint of the MADE (Modal Aerosol Dynamics model for Europe) to optimise initial and boundary values for aerosols using 4Dvar. A forward and an adjoint radiative transfer model is driven by the EURAD-IM as mapping between BLAOT (Boundary Layer Aerosol Optical Thickness) and internal aerosol species. Furthermore, its condensation scheme has been bypassed by an HDMR (High-Dimensional-Model-Representation) to ensure differentiability. In this study both in-situ measured PMx as well as satellite retrieved aerosol optical thicknesses have been assimilated and the effect on forecast performance has been investigated. The source of BLAOT is the aerosol retrieval system SYNAER (SYNergetic AErosol Retrieval) from DLR-DFD that retrieves AOT by making use of both AATSR/SCIAMACHY and AVHRR/GOME-2 data respectively. Its strengths are a large spatial coverage, near real-time availability, and the classification of five intrinsic aerosol species, namely water-solubles, water-insolubles, soot

  13. A novel four-dimensional radiotherapy planning strategy from a tumor-tracking beam's eye view.

    Science.gov (United States)

    Li, Guang; Cohen, Patrice; Xie, Huchen; Low, Daniel; Li, Diana; Rimner, Andreas

    2012-11-21

    To investigate the feasibility of four-dimensional radiotherapy (4DRT) planning from a tumor-tracking beam's eye view (ttBEV) with reliable gross tumor volume (GTV) delineation, realistic normal tissue representation, high planning accuracy and low clinical workload, we propose and validate a novel 4D conformal planning strategy based on a synthesized 3.5D computed tomographic (3.5DCT) image with a motion-compensated tumor. To recreate patient anatomy from a ttBEV in the moving tumor coordinate system for 4DRT planning (or 4D planning), the centers of delineated GTVs in all phase CT images of 4DCT were aligned, and then the aligned CTs were averaged to produce a new 3.5DCT image. This GTV-motion-compensated CT contains a motionless target (with motion artifacts minimized) and motion-blurred normal tissues (with a realistic temporal density average). Semi-automatic threshold-based segmentation of the tumor, lung and body was applied, while manual delineation was used for other organs at risk (OARs). To validate this 3.5DCT-based 4D planning strategy, five patients with peripheral lung lesions of small size (form deformable image registration (DIR). The DVH(3.5D) (for the 3.5DCT plan) was compared with both iDVH(4D) and DVH(4D). To quantify the DVH difference between the 3.5DCT plan and the 4DCT plan, two methods were used: relative difference (%) of the areas underneath the DVH curves and the volumes receiving more than 20% (V20) and 50% (V50) of prescribed dose of these 4D plans. The volume of the delineated GTV from different phase CTs varied dramatically from 24% to 112% among the five patients, whereas the GTV from 3.5DCT deviated from the averaged GTV in 4DCT by only -6%±6%. For planning tumor volume (PTV) coverage, the difference between the DVH(3.5D) and iDVH(4D) was negligible (equivalent to the 4DCT plan with <1% dose difference to the PTV and negligible dose difference in OARs. The 3.5DCT approach simplifies 4D planning and provides accurate dose

  14. Finite-size scaling relations for a four-dimensional Ising model on Creutz cellular automatons

    Science.gov (United States)

    Merdan, Z.; Güzelsoy, E.

    2011-06-01

    The four-dimensional Ising model is simulated on Creutz cellular automatons using finite lattices with linear dimensions 4 ≤ L ≤ 8. The temperature variations and finite-size scaling plots of the specific heat and the Binder parameter verify the theoretically predicted expression near the infinite lattice critical temperature for 7, 14, and 21 independent simulations. Approximate values for the critical temperature of the infinite lattice of Tc(∞) = 6.6965(35), 6.6961(30), 6.6960(12), 6.6800(3), 6.6801(2), 6.6802(1) and 6.6925(22) (without the logarithmic factor), 6.6921(22) (without the logarithmic factor), 6.6909(2) (without the logarithmic factor), 6.6822(13) (with the logarithmic factor), 6.6819(11) (with the logarithmic factor), and 6.6808(8) (with the logarithmic factor) are obtained from the intersection points of the specific heat curves, the Binder parameter curves, and straight line fits of specific heat maxima for 7, 14, and 21 independent simulations, respectively. As the number of independent simulations increases, the results, 6.6802(1) and 6.6808(8), are in very good agreement with the results of a series expansion of Tc(∞), 6.6817(15) and 6.6802(2), the dynamic Monte Carlo value Tc(∞) = 6.6803(1), the cluster Monte Carlo value Tc(∞) = 6.680(1), and the Monte Carlo value using the Metropolis-Wolff cluster algorithm Tc(∞) = 6.6802632 ± 5 . 10-5. The average values calculated for the critical exponent of the specific heat are α =- 0.0402(15), - 0.0393(12), - 0.0391(11) with 7, 14, and 21 independent simulations, respectively. As the number of independent simulations increases, the result, α =- 0.0391(11), agrees with the series expansions result, α =- 0.12 ± 0.03 and the Monte Carlo result using the Metropolis-Wolff cluster algorithm, α ≥ 0 ± 0.04. However, α =- 0.0391(11) is inconsistent with the renormalization group prediction of α = 0.

  15. GPU-based four-dimensional general-relativistic ray tracing

    Science.gov (United States)

    Kuchelmeister, Daniel; Müller, Thomas; Ament, Marco; Wunner, Günter; Weiskopf, Daniel

    2012-10-01

    This paper presents a new general-relativistic ray tracer that enables image synthesis on an interactive basis by exploiting the performance of graphics processing units (GPUs). The application is capable of visualizing the distortion of the stellar background as well as trajectories of moving astronomical objects orbiting a compact mass. Its source code includes metric definitions for the Schwarzschild and Kerr spacetimes that can be easily extended to other metric definitions, relying on its object-oriented design. The basic functionality features a scene description interface based on the scripting language Lua, real-time image output, and the ability to edit almost every parameter at runtime. The ray tracing code itself is implemented for parallel execution on the GPU using NVidia's Compute Unified Device Architecture (CUDA), which leads to performance improvement of an order of magnitude compared to a single CPU and makes the application competitive with small CPU cluster architectures. Program summary Program title: GpuRay4D Catalog identifier: AEMV_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEMV_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 73649 No. of bytes in distributed program, including test data, etc.: 1334251 Distribution format: tar.gz Programming language: C++, CUDA. Computer: Linux platforms with a NVidia CUDA enabled GPU (Compute Capability 1.3 or higher), C++ compiler, NVCC (The CUDA Compiler Driver). Operating system: Linux. RAM: 2 GB Classification: 1.5. External routines: OpenGL Utility Toolkit development files, NVidia CUDA Toolkit 3.2, Lua5.2 Nature of problem: Ray tracing in four-dimensional Lorentzian spacetimes. Solution method: Numerical integration of light rays, GPU-based parallel programming using CUDA, 3D

  16. Dose and Position Measurements using a Novel Four-Dimensional In Vivo Dosimetry System

    Science.gov (United States)

    Cherpak, Amanda

    This work presents a comprehensive characterization of the dosimetric and position measurement characteristics as well as clinical implementation of a novel four-dimensional in vivo dosimetry system, RADPOS. Preliminary dose and position measurements were first conducted to evaluate any deviation from known characteristics of metal-oxide semiconductor field-effect transistors, MOSFETs, and electromagnetic positioning systems when they are used alone. The system was then combined with a deformable tissue equivalent lung phantom to simulate respiratory-induced tumour motion and lung deformation and to evaluate the potential use of the system as an effective quality assurance tool for 4D conformal radiotherapy. The final phase of testing involved using the RADPOS 4D in vivo dosimetry system in two different clinical trials. The first involved characterizing the breathing patterns of lung cancer patients throughout the course of treatment and measuring inter-fraction variations in skin dose. Within this framework, the feasibility of general use of the RADPOS system on patients during daily treatment fractions was also assessed. The second trial involved a modified RADPOS detector that contained a MOSFET array, allowing for dose measurements at five different points. This detector was used to measure dose and position in the prostatic urethra throughout seed implantation for transperineal interstitial permanent prostate brachytherapy. It has been found that the dosimetric response is similar to that of a microMOSFET, when used alone, aside from a slightly higher variation in angular response. Position measurements can be obtained with an uncertainty of +/- 2 mm when the detector remains within a specific optimal volume with respect to the magnetic field transmitter and when interfering metal objects are kept at least 200 mm away. Combining the RADPOS system with a deformable lung equivalent phantom allowed for efficient quality assurance of 4D radiation therapy, as

  17. T2-weighted four dimensional magnetic resonance imaging with result-driven phase sorting

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yilin; Yin, Fang-Fang; Cai, Jing, E-mail: jing.cai@duke.edu [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27710 and Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Czito, Brian G. [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Bashir, Mustafa R. [Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 (United States)

    2015-08-15

    Purpose: T2-weighted MRI provides excellent tumor-to-tissue contrast for target volume delineation in radiation therapy treatment planning. This study aims at developing a novel T2-weighted retrospective four dimensional magnetic resonance imaging (4D-MRI) phase sorting technique for imaging organ/tumor respiratory motion. Methods: A 2D fast T2-weighted half-Fourier acquisition single-shot turbo spin-echo MR sequence was used for image acquisition of 4D-MRI, with a frame rate of 2–3 frames/s. Respiratory motion was measured using an external breathing monitoring device. A phase sorting method was developed to sort the images by their corresponding respiratory phases. Besides, a result-driven strategy was applied to effectively utilize redundant images in the case when multiple images were allocated to a bin. This strategy, selecting the image with minimal amplitude error, will generate the most representative 4D-MRI. Since we are using a different image acquisition mode for 4D imaging (the sequential image acquisition scheme) with the conventionally used cine or helical image acquisition scheme, the 4D dataset sufficient condition was not obviously and directly predictable. An important challenge of the proposed technique was to determine the number of repeated scans (N{sub R}) required to obtain sufficient phase information at each slice position. To tackle this challenge, the authors first conducted computer simulations using real-time position management respiratory signals of the 29 cancer patients under an IRB-approved retrospective study to derive the relationships between N{sub R} and the following factors: number of slices (N{sub S}), number of 4D-MRI respiratory bins (N{sub B}), and starting phase at image acquisition (P{sub 0}). To validate the authors’ technique, 4D-MRI acquisition and reconstruction were simulated on a 4D digital extended cardiac-torso (XCAT) human phantom using simulation derived parameters. Twelve healthy volunteers were involved

  18. Physical performance evaluation of a 256-slice CT-scanner for four-dimensional imaging.

    Science.gov (United States)

    Mori, Shinichiro; Endo, Masahiro; Tsunoo, Takanori; Kandatsu, Susumu; Tanada, Shuji; Aradate, Hiroshi; Saito, Yasuo; Miyazaki, Hiroaki; Satoh, Kazumasa; Matsushita, Satoshi; Kusakabe, Masahiro

    2004-06-01

    We have developed a prototype 256-slice CT-scanner for four-dimensional (4D) imaging that employs continuous rotations of a cone-beam. Since a cone-beam scan along a circular orbit does not collect a complete set of data to make an exact reconstruction of a volume [three-dimensional (3D) image], it might cause disadvantages or artifacts. To examine effects of the cone-beam data collection on image quality, we have evaluated physical performance of the prototype 256-slice CT-scanner with 0.5 mm slices and compared it to that of a 16-slice CT-scanner with 0.75 mm slices. As a result, we found that image noise, uniformity, and high contrast detectability were independent of z coordinate. A Feldkamp artifact was observed in distortion measurements. Full width at half maximum (FWHM) of slice sensitivity profiles (SSP) increased with z coordinate though it seemed to be caused by other reasons than incompleteness of data. With regard to low contrast detectability, smaller objects were detected more clearly at the midplane (z = 0 mm) than at z = 40 mm, though circular-band like artifacts affected detection. The comparison between the 16-slice and the 256-slice scanners showed better performance for the 16-slice scanner regarding the SSP, low contrast detectability, and distortion. The inferiorities of the 256-slice scanner in other than distortion measurement (Feldkamp artifact) seemed to be partly caused by the prototype nature of the scanner and should be improved in the future scanner. The image noise, uniformity, and high contrast detectability were almost identical for both CTs. The 256-slice scanner was superior to the 16-slice scanner regarding the PSF, though it was caused by the smaller transverse beam width of the 256-slice scanner. In order to compare both scanners comprehensively in terms of exposure dose, noise, slice thickness, and transverse spatial resolution, K=Dsigma2ha3 was calculated, where D was exposure dose (CT dose index), sigma was magnitude of

  19. Four-dimensional cone beam CT reconstruction and enhancement using a temporal nonlocal means method

    Energy Technology Data Exchange (ETDEWEB)

    Jia Xun; Tian Zhen; Lou Yifei; Sonke, Jan-Jakob; Jiang, Steve B. [Center for Advanced Radiotherapy Technologies and Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California 92037 (United States); School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30318 (United States); Department of Radiation Oncology, Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Plesmanlaan 121, 1066 CX Amsterdam (Netherlands); Center for Advanced Radiotherapy Technologies and Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, California 92037 (United States)

    2012-09-15

    Purpose: Four-dimensional cone beam computed tomography (4D-CBCT) has been developed to provide respiratory phase-resolved volumetric imaging in image guided radiation therapy. Conventionally, it is reconstructed by first sorting the x-ray projections into multiple respiratory phase bins according to a breathing signal extracted either from the projection images or some external surrogates, and then reconstructing a 3D CBCT image in each phase bin independently using FDK algorithm. This method requires adequate number of projections for each phase, which can be achieved using a low gantry rotation or multiple gantry rotations. Inadequate number of projections in each phase bin results in low quality 4D-CBCT images with obvious streaking artifacts. 4D-CBCT images at different breathing phases share a lot of redundant information, because they represent the same anatomy captured at slightly different temporal points. Taking this redundancy along the temporal dimension into account can in principle facilitate the reconstruction in the situation of inadequate number of projection images. In this work, the authors propose two novel 4D-CBCT algorithms: an iterative reconstruction algorithm and an enhancement algorithm, utilizing a temporal nonlocal means (TNLM) method. Methods: The authors define a TNLM energy term for a given set of 4D-CBCT images. Minimization of this term favors those 4D-CBCT images such that any anatomical features at one spatial point at one phase can be found in a nearby spatial point at neighboring phases. 4D-CBCT reconstruction is achieved by minimizing a total energy containing a data fidelity term and the TNLM energy term. As for the image enhancement, 4D-CBCT images generated by the FDK algorithm are enhanced by minimizing the TNLM function while keeping the enhanced images close to the FDK results. A forward-backward splitting algorithm and a Gauss-Jacobi iteration method are employed to solve the problems. The algorithms implementation on

  20. The Value of Contrast Echocardiography

    Directory of Open Access Journals (Sweden)

    Shannon C. Treiber

    2016-01-01

    Full Text Available Purpose: There is much evidence-based research proving the effectiveness of contrast echocardiography, but there are still questions and concerns about its specific uses. This study tested the effectiveness of contrast echocardiography in defining the left ventricular endocardial border. Methods: From 30 patients, a total of 60 echocardiograms –– 30 with and 30 without use of contrast –– were retrospectively reviewed by four blinded cardiologists with advanced training in echocardiography. No single cardiologist reviewed contrast and noncontrast images of the same patient. Each set of 30 echocardiograms was then studied for wall-motion scoring. Visualization of left ventricular wall segments and a global visualization confidence level of interpretation were recorded. Results: Of all wall segments (N = 510, 91% were visualized in echocardiograms with use of contrast, whereas 75% of the walls were visualized in echocardiograms without contrast (P < 0.001. Of 30 examinations, 17 contrast echocardiograms were read with high confidence compared to 6 without contrast use (P = 0.004. The number of walls visualized with contrast was increased in 18 patients (60%, whereas noncontrast echocardiograms yielded more visualized walls in 6 patients (20%, P = 0.002. Conclusions: This study demonstrates that contrast is valuable to echocardiographic imaging. Its use should be supported throughout echocardiography clinics and encouraged in certain patients for whom resting and stress echocardiography results without contrast often prove uninterpretable.

  1. Four-dimensional optical multiband-OFDM for beyond 1.4 Tb/s serial optical transmission.

    Science.gov (United States)

    Djordjevic, Ivan; Batshon, Hussam G; Xu, Lei; Wang, Ting

    2011-01-17

    We propose a four-dimensional (4D) coded multiband-OFDM scheme suitable for beyond 1.4 Tb/s serial optical transport. The proposed scheme organizes the N-dimensional (ND) signal constellation points in the form of signal matrix; employs 2D-inverse FFT and 2D-FFT to perform modulation and demodulation, respectively; and exploits both orthogonal polarizations. This scheme can fully exploit advantages of OFDM to deal with chromatic dispersion, PMD and PDL effects; and multidimensional signal constellations to improve OSNR sensitivity of conventional optical OFDM. The improvement of 4D-OFDM over corresponding polarization-multiplexed QAM (with the same number of constellation points) ranges from 1.79 dB for 16 signal constellation point-four-dimensional-OFDM (16-4D-OFDM) up to 4.53 dB for 128-4D-OFDM.

  2. A novel four-dimensional radiotherapy planning strategy from a tumor-tracking beam's eye view

    Science.gov (United States)

    Li, Guang; Cohen, Patrice; Xie, Huchen; Low, Daniel; Li, Diana; Rimner, Andreas

    2012-11-01

    To investigate the feasibility of four-dimensional radiotherapy (4DRT) planning from a tumor-tracking beam's eye view (ttBEV) with reliable gross tumor volume (GTV) delineation, realistic normal tissue representation, high planning accuracy and low clinical workload, we propose and validate a novel 4D conformal planning strategy based on a synthesized 3.5D computed tomographic (3.5DCT) image with a motion-compensated tumor. To recreate patient anatomy from a ttBEV in the moving tumor coordinate system for 4DRT planning (or 4D planning), the centers of delineated GTVs in all phase CT images of 4DCT were aligned, and then the aligned CTs were averaged to produce a new 3.5DCT image. This GTV-motion-compensated CT contains a motionless target (with motion artifacts minimized) and motion-blurred normal tissues (with a realistic temporal density average). Semi-automatic threshold-based segmentation of the tumor, lung and body was applied, while manual delineation was used for other organs at risk (OARs). To validate this 3.5DCT-based 4D planning strategy, five patients with peripheral lung lesions of small size (<5 cm3) and large motion range (1.2-3.5 cm) were retrospectively studied for stereotactic body radiotherapy (SBRT) using 3D conformal radiotherapy planning tools. The 3.5DCT-based 4D plan (3.5DCT plan) with 9-10 conformal beams was compared with the 4DCT-based 4D plan (4DCT plan). The 4DCT plan was derived from multiple 3D plans based on all phase CT images, each of which used the same conformal beam configuration but with an isocenter shift to aim at the moving tumor and a minor beam aperture and weighting adjustment to maintain plan conformality. The dose-volume histogram (DVH) of the 4DCT plan was created with two methods: one is an integrated DVH (iDVH4D), which is defined as the temporal average of all 3D-phase-plan DVHs, and the other (DVH4D) is based on the dose distribution in a reference phase CT image by dose warping from all phase plans using the

  3. Why is the World four-dimensional? Hermann Weyl’s 1955 argument and the topology of causation

    Science.gov (United States)

    De Bianchi, Silvia

    2017-08-01

    This paper approaches the question of space dimensionality by discussing a neglected argument proposed by Hermann Weyl in 1955. In Why is the World Four-Dimensional? (1955), Weyl offered a different argument from the one generally attributed to him and presented in Raum-Zeit-Materie. In the first sections of the paper, this new argument and its features are spelled-out, and in the last section, I shall develop some useful remarks on the concept of topology of causation that can still inform our reflection on the dimensionality of the world.

  4. Hemodynamic Measurement Using Four-Dimensional Phase-Contrast MRI: Quantification of Hemodynamic Parameters and Clinical Applications

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Hojin [POSTECH Biotech Center, Pohang University of Science and Technology, Pohang 37673 (Korea, Republic of); Kim, Guk Bae [Asan Institute of Life Science, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Kweon, Jihoon [Department of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Lee, Sang Joon [POSTECH Biotech Center, Pohang University of Science and Technology, Pohang 37673 (Korea, Republic of); Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang 37673 (Korea, Republic of); Kim, Young-Hak [Department of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Lee, Deok Hee; Yang, Dong Hyun [Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Kim, Namkug [Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of); Department of Convergence Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505 (Korea, Republic of)

    2016-11-01

    Recent improvements have been made to the use of time-resolved, three-dimensional phase-contrast (PC) magnetic resonance imaging (MRI), which is also named four-dimensional (4D) PC-MRI or 4D flow MRI, in the investigation of spatial and temporal variations in hemodynamic features in cardiovascular blood flow. The present article reviews the principle and analytical procedures of 4D PC-MRI. Various fluid dynamic biomarkers for possible clinical usage are also described, including wall shear stress, turbulent kinetic energy, and relative pressure. Lastly, this article provides an overview of the clinical applications of 4D PC-MRI in various cardiovascular regions.

  5. Hemodynamic measurement using four-dimensional phase-contrast MRI: Quantification of hemodynamic parameters and clinical applications

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Ho Jin; Lee, Sang Joon [POSTECH Biotech Center, Pohang University of Science and Technology, Pohang (Korea, Republic of); Kim, Guk Bae; Kweon, Ji Hoon; Kim, Young Hak; Lee, Deok Hee; Yang, Dong Hyun; KIm, Nam Kug [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    2016-07-15

    Recent improvements have been made to the use of time-resolved, three-dimensional phase-contrast (PC) magnetic resonance imaging (MRI), which is also named four-dimensional (4D) PC-MRI or 4D flow MRI, in the investigation of spatial and temporal variations in hemodynamic features in cardiovascular blood flow. The present article reviews the principle and analytical procedures of 4D PC-MRI. Various fluid dynamic biomarkers for possible clinical usage are also described, including wall shear stress, turbulent kinetic energy, and relative pressure. Lastly, this article provides an overview of the clinical applications of 4D PC-MRI in various cardiovascular regions.

  6. Four-dimensional anti-de Sitter black holes from a three-dimensional perspective Full complexity

    CERN Document Server

    Zanchin, V T; Lemos, J P S

    2002-01-01

    The dimensional reduction of black hole solutions in four-dimensional (4D) general relativity is performed and new 3D black hole solutions are obtained. Considering a 4D spacetime with one spacelike Killing vector, it is possible to split the Einstein-Hilbert-Maxwell action with a cosmological term in terms of 3D quantities. Definitions of quasilocal mass and charges in 3D spacetimes are reviewed. The analysis is then particularized to the toroidal charged rotating anti-de Sitter black hole. The reinterpretation of the fields and charges in terms of a three-dimensional point of view is given in each case, and the causal structure analyzed.

  7. Phantom-based evaluations of two binning algorithms for four-dimensional CT reconstruction in lung cancer radiation therapy

    Institute of Scientific and Technical Information of China (English)

    Fuli Zhang; Huayong Jiang; Weidong Xu; Yadi Wang ; Qingzhi Liu; Na Lu; Diandian Chen; Bo Yao

    2014-01-01

    Objective: The purpose of this study was to evaluate the performance of the phase-binning algorithm and am-plitude-binning algorithm for four-dimensional computed tomography (4DCT) reconstruction in lung cancer radiation therapy. Methods: Quasar phantom data were used for evaluation.Aphantom of known geometry was mounted on a four-dimensional (4D) motion platform programmed with twelve respiratory waves (twelve lung patients trajectories) and scanned with a Philips Bril iance Big bore 16-slice CT simulator. The 4DCT images were reconstructed using both phase- and amplitude-binning algorithms. Internal target volumes (ITVs) of the phase- and amplitude-binned image sets were compared by evaluation of shape and volume distortions. Results: The phantom experiments il ustrated that, as expected, maximum inhalation occurred at the 0% amplitude and maximum exhalation occurred at the 50% amplitude of the amplitude-binned 4DCT image sets. The amplitude-binned algorithm rendered smal er ITV than the phase-binning algorithm. Conclusion: The amplitude-binning algorithm for 4DCT reconstruction may have a potential advantage in reducing the margin and protecting normal lung tissue from unnecessary irradiation.

  8. Motion of particles on a Four-Dimensional Asymptotically AdS Black Hole with Scalar Hair

    CERN Document Server

    Gonzalez, P A; Vasquez, Yerko

    2015-01-01

    Motivated by black hole solutions with matter fields outside their horizon, we study the effect of these matter fields in the motion of massless and massive particles. We consider as background a four-dimensional asymptotically AdS black hole with scalar hair. The geodesics are studied numerically and we discuss about the differences in the motion of particles between the four-dimensional asymptotically AdS black holes with scalar hair and their no-hair limit, that is, Schwarzschild AdS black holes. Mainly, we found that there are bounded orbits like planetary orbits in this background. However, the periods associated to circular orbits are modified by the presence of the scalar hair. Besides, we found that some classical tests such as perihelion precession, deflection of light and gravitational time delay have the standard value of general relativity plus a correction term coming from the cosmological constant and the scalar hair. Finally, we found a specific value of the parameter associated to the scalar h...

  9. Motion of particles on a four-dimensional asymptotically AdS black hole with scalar hair

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, P.A.; Olivares, Marco [Universidad Diego Portales, Facultad de Ingenieria, Santiago (Chile); Vasquez, Yerko [Universidad de La Serena, Departamento de Fisica, Facultad de Ciencias, La Serena (Chile)

    2015-10-15

    Motivated by black hole solutions with matter fields outside their horizon, we study the effect of these matter fields on the motion of massless and massive particles. We consider as background a four-dimensional asymptotically AdS black hole with scalar hair. The geodesics are studied numerically and we discuss the differences in the motion of particles between the four-dimensional asymptotically AdS black holes with scalar hair and their no-hair limit, that is, Schwarzschild AdS black holes. Mainly, we found that there are bounded orbits like planetary orbits in this background. However, the periods associated to circular orbits are modified by the presence of the scalar hair. Besides, we found that some classical tests such as perihelion precession, deflection of light, and gravitational time delay have the standard value of general relativity plus a correction term coming from the cosmological constant and the scalar hair. Finally, we found a specific value of the parameter associated to the scalar hair, in order to explain the discrepancy between the theory and the observations, for the perihelion precession of Mercury and light deflection. (orig.)

  10. An explicit four-dimensional variational data assimilation method based on the proper orthogonal decomposition: Theoretics and evaluation

    Institute of Scientific and Technical Information of China (English)

    TIAN XiangJun; XIE ZhengHui

    2009-01-01

    The proper orthogonal decomposition (POD) method is used to construct a set of basis functions for spanning the ensemble of data in a certain least squares optimal sense. Compared with the singular value decomposition (SVD), the POD basis functions can capture more energy in the forecast ensemble space and can represent its spatial structure and temporal evolution more effectively. After the analysis variables are expressed by a truncated expansion of the POD basis vectors in the ensemble space, the control variables appear explicitly in the cost function, so that the adjoint model, which is used to de-rive the gradient of the cost function with respect to the control variables, is no longer needed. The application of this new technique significantly simplifies the data assimilation process. Several as-similation experiments show that this POD-based explicit four-dimensional variational data assimila-tion method performs much better than the usual ensemble Kalman filter method on both enhancing the assimilation precision and reducing the computation cost. It is also better than the SVD-based ex-plicit four-dimensional assimilation method, especially when the forecast model is not perfect and the forecast error comes from both the noise of the initial filed and the uncertainty of the forecast model.

  11. Investigating the Impact on Modeled Ozone Concentrations Using Meteorological Fields From WRF With and Updated Four-Dimensional Data Assimilation Approach”

    Science.gov (United States)

    The four-dimensional data assimilation (FDDA) technique in the Weather Research and Forecasting (WRF) meteorological model has recently undergone an important update from the original version. Previous evaluation results have demonstrated that the updated FDDA approach in WRF pr...

  12. Maternal psychological impact of fetal echocardiography.

    Science.gov (United States)

    Sklansky, Mark; Tang, Alvin; Levy, Denis; Grossfeld, Paul; Kashani, Iraj; Shaughnessy, Robin; Rothman, Abraham

    2002-02-01

    The maternal psychological impact of fetal echocardiography may be deleterious in the face of newly diagnosed congenital heart disease. This questionnaire-based study prospectively examined the psychological impact of both normal and abnormal fetal echocardiography. Normal fetal echocardiography decreased maternal anxiety, increased happiness, and increased the closeness women felt toward their unborn children. In contrast, when fetal echocardiography detected congenital heart disease, maternal anxiety typically increased, and mothers commonly felt less happy about being pregnant. However, among women who had recently delivered infants with congenital heart disease, those who had had fetal echocardiography during the pregnancy felt less responsible for their infants' defects and tended to have improved their relationships with the infants' fathers after the prenatal diagnosis of congenital heart disease. Further study of the psychological and medical impact of fetal echocardiography will be necessary to define and optimize the clinical value of this powerful diagnostic tool.

  13. Four-dimensional symmetry from a broad viewpoint. II Invariant distribution of quantized field oscillators and questions on infinities

    Science.gov (United States)

    Hsu, J. P.

    1983-01-01

    The foundation of the quantum field theory is changed by introducing a new universal probability principle into field operators: one single inherent and invariant probability distribution P(/k/) is postulated for boson and fermion field oscillators. This can be accomplished only when one treats the four-dimensional symmetry from a broad viewpoint. Special relativity is too restrictive to allow such a universal probability principle. A radical length, R, appears in physics through the probability distribution P(/k/). The force between two point particles vanishes when their relative distance tends to zero. This appears to be a general property for all forces and resembles the property of asymptotic freedom. The usual infinities in vacuum fluctuations and in local interactions, however complicated they may be, are all removed from quantum field theories. In appendix A a simple finite and unitary theory of unified electroweak interactions is discussed without assuming Higgs scalar bosons.

  14. Energy analysis of four dimensional extended hyperbolic Scarf I plus three dimensional separable trigonometric noncentral potentials using SUSY QM approach

    Science.gov (United States)

    Suparmi, A.; Cari, C.; Deta, U. A.; Handhika, J.

    2016-11-01

    The non-relativistic energies and wave functions of extended hyperbolic Scarf I plus separable non-central shape invariant potential in four dimensions are investigated using Supersymmetric Quantum Mechanics (SUSY QM) Approach. The three dimensional separable non-central shape invariant angular potential consists of trigonometric Scarf II, Manning Rosen and Poschl-Teller potentials. The four dimensional Schrodinger equation with separable shape invariant non-central potential is reduced into four one dimensional Schrodinger equations through variable separation method. By using SUSY QM, the non-relativistic energies and radial wave functions are obtained from radial Schrodinger equation, the orbital quantum numbers and angular wave functions are obtained from angular Schrodinger equations. The extended potential means there is perturbation terms in potential and cause the decrease in energy spectra of Scarf I potential.

  15. Prostate displacement during transabdominal ultrasound image-guided radiotherapy assessed by real-time four-dimensional transperineal monitoring

    DEFF Research Database (Denmark)

    Baker, Mariwan; Behrens, Claus F.

    2015-01-01

    Background. Transabdominal ultrasound (TAUS) imaging is currently available for localizing the prostate in daily image-guided radiotherapy (IGRT). The aim of this study was to determine the induced prostate displacement during such TAUS imaging. The prostate displacement was monitored using a novel...... transperineal four-dimensional (4D) US (TPUS) system. Material and methods. Ten prostate cancer patients, with a mean age of 68 years (58/76), were US scanned in the computed tomography (CT) room utilizing the Clarity 4D TPUS monitoring system. The patients were asked to comply with a moderate bladder fi lling...... a TAUS scan. The time dependent prostate displacements induced by the 2D probe pressure were recorded for the three orthogonal directions. In total 42 monitoring curves with applied 2D probe were recorded. Results. Data analysis of 42 US scans resulted in pressure induced prostate displacements with mean...

  16. Solving the four-dimensional {ital NN}-{pi}{ital NN} equations for scalars below the meson-production threshold

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, D.R.; Afnan, I.R. [Department of Physics, The Flinders University of South Australia, GPO Box 2100, Adelaide 5001 (Australia)

    1996-10-01

    The four-dimensional {ital NN}-{pi}{ital NN} equations are adapted to the case of scalar particles with a {phi}{sup 2}{sigma} interaction Lagrangian and solved for energies below the {sigma}-production threshold. This is achieved in the approximation where {phi}{sigma} scattering is dominated by the {ital s}-channel {phi}-pole term. The importance of the removal of double counting is investigated and a detailed comparison of the results of a covariant coupled-channel formulation and the Bethe-Salpeter equation in the ladder and ladder plus crossed-box approximations is presented. A brief discussion of the extension of the method to energies above the {sigma}-production threshold is given. {copyright} {ital 1996 The American Physical Society.}

  17. Solving the four-dimensional NN-πNN equations for scalars below the meson-production threshold

    Science.gov (United States)

    Phillips, D. R.; Afnan, I. R.

    1996-10-01

    The four-dimensional NN-πNN equations are adapted to the case of scalar particles with a φ2σ interaction Lagrangian and solved for energies below the σ-production threshold. This is achieved in the approximation where φσ scattering is dominated by the s-channel φ-pole term. The importance of the removal of double counting is investigated and a detailed comparison of the results of a covariant coupled-channel formulation and the Bethe-Salpeter equation in the ladder and ladder plus crossed-box approximations is presented. A brief discussion of the extension of the method to energies above the σ-production threshold is given.

  18. Measuring working memory is all fun and games: a four-dimensional spatial game predicts cognitive task performance.

    Science.gov (United States)

    Atkins, Sharona M; Sprenger, Amber M; Colflesh, Gregory J H; Briner, Timothy L; Buchanan, Jacob B; Chavis, Sydnee E; Chen, Sy-Yu; Iannuzzi, Gregory L; Kashtelyan, Vadim; Dowling, Eamon; Harbison, J Isaiah; Bolger, Donald J; Bunting, Michael F; Dougherty, Michael R

    2014-01-01

    We developed a novel four-dimensional spatial task called Shapebuilder and used it to predict performance on a wide variety of cognitive tasks. In six experiments, we illustrate that Shapebuilder: (1) Loads on a common factor with complex working memory (WM) span tasks and that it predicts performance on quantitative reasoning tasks and Ravens Progressive Matrices (Experiment 1), (2) Correlates well with traditional complex WM span tasks (Experiment 2), predicts performance on the conditional go/no go task (Experiment 3) and N-back (Experiment 4), and showed weak or nonsignificant correlations with the Attention Networks Task (Experiment 5), and task switching (Experiment 6). Shapebuilder shows that it exhibits minimal skew and kurtosis, and shows good reliability. We argue that Shapebuilder has many advantages over existing measures of WM, including the fact that it is largely language independent, is not prone to ceiling effects, and take less than 6 min to complete on average.

  19. Sensitivity of the model error parameter specification in weak-constraint four-dimensional variational data assimilation

    Science.gov (United States)

    Shaw, Jeremy A.; Daescu, Dacian N.

    2017-08-01

    This article presents the mathematical framework to evaluate the sensitivity of a forecast error aspect to the input parameters of a weak-constraint four-dimensional variational data assimilation system (w4D-Var DAS), extending the established theory from strong-constraint 4D-Var. Emphasis is placed on the derivation of the equations for evaluating the forecast sensitivity to parameters in the DAS representation of the model error statistics, including bias, standard deviation, and correlation structure. A novel adjoint-based procedure for adaptive tuning of the specified model error covariance matrix is introduced. Results from numerical convergence tests establish the validity of the model error sensitivity equations. Preliminary experiments providing a proof-of-concept are performed using the Lorenz multi-scale model to illustrate the theoretical concepts and potential benefits for practical applications.

  20. Non-critical, near extremal AdS6 background as a holographic laboratory of four dimensional YM theory

    Science.gov (United States)

    Kuperstein, S.; Sonnenschein, J.

    2004-11-01

    We study certain properties of the low energy regime of a theory which resembles four dimensional YM theory in the framework of a non-critical holographic gravity dual. We use for the latter the near extremal AdS6 non-critical SUGRA. We extract the glueball spectra that associates with the fluctuations of the dilaton, one form and the graviton and compare the results to those of the critical near extremal D4 model and lattice simulations. We show an area law behavior for the Wilson loop and screening for the 't Hooft loop. The Luscher term is found to be -(3π/24L). We derive the Regge trajectories of glueballs associated with the spinning folded string configurations.

  1. Testing a four-dimensional variational data assimilation method using an improved intermediate coupled model for ENSO analysis and prediction

    Science.gov (United States)

    Gao, Chuan; Wu, Xinrong; Zhang, Rong-Hua

    2016-07-01

    A four-dimensional variational (4D-Var) data assimilation method is implemented in an improved intermediate coupled model (ICM) of the tropical Pacific. A twin experiment is designed to evaluate the impact of the 4D-Var data assimilation algorithm on ENSO analysis and prediction based on the ICM. The model error is assumed to arise only from the parameter uncertainty. The "observation" of the SST anomaly, which is sampled from a "truth" model simulation that takes default parameter values and has Gaussian noise added, is directly assimilated into the assimilation model with its parameters set erroneously. Results show that 4D-Var effectively reduces the error of ENSO analysis and therefore improves the prediction skill of ENSO events compared with the non-assimilation case. These results provide a promising way for the ICM to achieve better real-time ENSO prediction.

  2. Four Dimensional Graphene

    CERN Document Server

    Drissi, L B; Bousmina, M

    2011-01-01

    Mimicking pristine 2D graphene, we revisit the BBTW model for 4D lattice QCD given in ref.[5] by using the hidden SU(5) symmetry of the 4D hyperdiamond lattice H_4. We first study the link between the H_4 and SU(5); then we refine the BBTW 4D lattice action by using the weight vectors \\lambda_1, \\lambda_2, \\lambda_3, \\lambda_4, \\lambda_5 of the 5-dimensional representation of SU(5) satisfying {\\Sigma}_i\\lambda_i=0. After that we study explicitly the solutions of the zeros of the Dirac operator D in terms of the SU(5) simple roots \\alpha_1, \\alpha_2, \\alpha_3, \\alpha_4 generating H_4; and its fundamental weights \\omega_1, \\omega_2, \\omega_3, \\omega_4 which generate the reciprocal lattice H_4^\\ast. It is shown, amongst others, that these zeros live at the sites of H_4^\\ast; and the continuous limit D is given by ((id\\surd5)/2) \\gamma^\\muk_\\mu with d, \\gamma^\\mu and k_\\mu standing respectively for the lattice parameter of H_4, the usual 4 Dirac matrices and the 4D wave vector. Other features such as differences ...

  3. Four-dimensional graphene

    Science.gov (United States)

    Drissi, L. B.; Saidi, E. H.; Bousmina, M.

    2011-07-01

    Mimicking pristine 2D graphene, we revisit the BBTW model for 4D lattice QCD given in [P. F. Bedaque , Phys. Rev. DPRVDAQ1550-7998 78, 017502 (2008)10.1103/PhysRevD.78.017502] by using the hidden SU(5) symmetry of the 4D hyperdiamond lattice H4. We first study the link between the H4 and SU(5); then we refine the BBTW 4D lattice action by using the weight vectors λ1, λ2, λ3, λ4, and λ5 of the five-dimensional representation of SU(5) satisfying ∑iλi=0. After that, we study explicitly the solutions of the zeros of the Dirac operator D in terms of the SU(5) simple roots α1, α2, α3, and α4 generating H4; and its fundamental weights ω1, ω2, ω3 ω4 which generate the reciprocal lattice H4*. It is shown, among others, that these zeros live at the sites of H4*; and the continuous limit D is given by (id5)/(2) γμkμ with d, γμ, and kμ standing, respectively, for the lattice parameter of H4, the usual 4 Dirac matrices and the 4D wave vector. Other features, such as differences with BBTW model as well as the link between the Dirac operator following from our construction and the one suggested by Creutz using quaternions, are also given.

  4. Investigation of four-dimensional computed tomography-based pulmonary ventilation imaging in patients with emphysematous lung regions.

    Science.gov (United States)

    Yamamoto, Tokihiro; Kabus, Sven; Klinder, Tobias; Lorenz, Cristian; von Berg, Jens; Blaffert, Thomas; Loo, Billy W; Keall, Paul J

    2011-04-07

    A pulmonary ventilation imaging technique based on four-dimensional (4D) computed tomography (CT) has advantages over existing techniques. However, physiologically accurate 4D-CT ventilation imaging has not been achieved in patients. The purpose of this study was to evaluate 4D-CT ventilation imaging by correlating ventilation with emphysema. Emphysematous lung regions are less ventilated and can be used as surrogates for low ventilation. We tested the hypothesis: 4D-CT ventilation in emphysematous lung regions is significantly lower than in non-emphysematous regions. Four-dimensional CT ventilation images were created for 12 patients with emphysematous lung regions as observed on CT, using a total of four combinations of two deformable image registration (DIR) algorithms: surface-based (DIR(sur)) and volumetric (DIR(vol)), and two metrics: Hounsfield unit (HU) change (V(HU)) and Jacobian determinant of deformation (V(Jac)), yielding four ventilation image sets per patient. Emphysematous lung regions were detected by density masking. We tested our hypothesis using the one-tailed t-test. Visually, different DIR algorithms and metrics yielded spatially variant 4D-CT ventilation images. The mean ventilation values in emphysematous lung regions were consistently lower than in non-emphysematous regions for all the combinations of DIR algorithms and metrics. V(HU) resulted in statistically significant differences for both DIR(sur) (0.14 ± 0.14 versus 0.29 ± 0.16, p = 0.01) and DIR(vol) (0.13 ± 0.13 versus 0.27 ± 0.15, p Jac) resulted in non-significant differences for both DIR(sur) (0.15 ± 0.07 versus 0.17 ± 0.08, p = 0.20) and DIR(vol) (0.17 ± 0.08 versus 0.19 ± 0.09, p = 0.30). This study demonstrated the strong correlation between the HU-based 4D-CT ventilation and emphysema, which indicates the potential for HU-based 4D-CT ventilation imaging to achieve high physiologic accuracy. A further study is needed to confirm these results.

  5. Theoretical study of different features of the fission process of excited nuclei in the framework of the modified statistical model and four-dimensional dynamical model

    Science.gov (United States)

    Eslamizadeh, H.

    2017-02-01

    Evaporation residue cross section, fission probability, anisotropy of fission fragment angular distribution, mass and energy distributions of fission fragments and the pre-scission neutron multiplicity for the excited compound nuclei {}168{{Y}}{{b}}, {}172{{Y}}{{b}}, {}178{{W}} and {}227{{P}}{{a}} produced in fusion reactions have been calculated in the framework of the modified statistical model and multidimensional dynamical model. In the dynamical calculations, the dynamics of fission of excited nuclei has been studied by solving three- and four-dimensional Langevin equations with dissipation generated through the chaos-weighted wall and window friction formula. Three collective shape coordinates plus the projection of total spin of the compound nucleus to the symmetry axis, K, were considered in the four-dimensional dynamical model. A non-constant dissipation coefficient of K, {γ }k, was applied in the four-dimensional dynamical calculations. A comparison of the results of the three- and four-dimensional dynamical models with the experimental data showed that the results of the four-dimensional dynamical model for the evaporation residue cross section, fission probability, anisotropy of fission fragment angular distribution, mass and energy distributions of fission fragments and the pre-scission neutron multiplicity are in better agreement with the experimental data. It was also shown that the modified statistical model can reproduce the above-mentioned experimental data by choosing appropriate values of the temperature coefficient of the effective potential, λ , and the scaling factor of the fission-barrier height, {r}s.

  6. Pediatric echocardiography laboratory organization and clinical productivity.

    Science.gov (United States)

    Lai, Wyman W; Srivastava, Shubhika; Cohen, Meryl S; Frommelt, Peter C; Allada, Vivek

    2013-10-01

    The American Society of Echocardiography's Committee on Pediatric Echocardiography Laboratory Productivity (C-PELP) was formed to study the organizational and productivity issues particular to academic pediatric echocardiography laboratories. After much deliberation, the committee chose studies per physician full-time equivalent per day --the average number of studies interpreted per day by a full-time echocardiography physician dedicated to the laboratory -as the primary measure of physician productivity. A survey was sent to 74 North American pediatric echocardiography laboratory directors. The aims of the survey were to (1) determine the annual laboratory volume and types of echocardiographic studies performed, (2) define the average number of studies performed by a pediatric cardiac sonographer in a year, (3) assess the productivity of echocardiography physicians, and (4) identify factors (programmatic or laboratory related) that affect clinical productivity. There were 54 responses to the C-PELP 2011 survey. The average number of studies per physician full-time equivalent per day was 15.0 + 4.5 (median, 13.8; range, 6.2 -27.1), and the average number of studies performed per year by a sonographer was 1,297 + 326 (median, 1,279; range 717 -2,475). These figures were not adjusted for case complexity, time requirement for transesophageal echocardiography, level of expertise, or availability of sonographer assistance. Moreover, the issues of study quality and accuracy were not addressed. The C-PELP 2011 survey gathered important information on the current organization and staffing of academic pediatric echocardiography laboratories, but the committee did not attempt to craft guidelines or recommendations on staffing requirements. The results of the survey, however, should provide a framework for additional investigation into the optimal structure and staffing of pediatric echocardiography laboratories. Copyright © 2013 American Society of Echocardiography

  7. Clocking the anisotropic lattice dynamics of multi-walled carbon nanotubes by four-dimensional ultrafast transmission electron microscopy

    Science.gov (United States)

    Cao, Gaolong; Sun, Shuaishuai; Li, Zhongwen; Tian, Huanfang; Yang, Huaixin; Li, Jianqi

    2015-02-01

    Recent advances in the four-dimensional ultrafast transmission electron microscope (4D-UTEM) with combined spatial and temporal resolutions have made it possible to directly visualize structural dynamics of materials at the atomic level. Herein, we report on our development on a 4D-UTEM which can be operated properly on either the photo-emission or the thermionic mode. We demonstrate its ability to obtain sequences of snapshots with high spatial and temporal resolutions in the study of lattice dynamics of the multi-walled carbon nanotubes (MWCNTs). This investigation provides an atomic level description of remarkable anisotropic lattice dynamics at the picosecond timescales. Moreover, our UTEM measurements clearly reveal that distinguishable lattice relaxations appear in intra-tubular sheets on an ultrafast timescale of a few picoseconds and after then an evident lattice expansion along the radial direction. These anisotropic behaviors in the MWCNTs are considered arising from the variety of chemical bonding, i.e. the weak van der Waals bonding between the tubular planes and the strong covalent sp2-hybridized bonds in the tubular sheets.

  8. String or brane-like solutions in four-dimensional Einstein gravity in the presence of cosmological constant

    CERN Document Server

    Lee, Youngone; Kim, Hyeong-Chan; Lee, Jungjai

    2011-01-01

    We investigate string or brane-like solutions for four-dimensional vacuum Einstein equations in the presence of cosmological constant. For the case of negative cosmological constant, the BTZ black string is the only warped stringlike solution. The general solutions for non-warped branelike configurations are found and they are characterized by the ADM mass density and two tensions. Interestingly, the sum of these tensions is equal to the minus of the mass density. Other than the well known black 2-brane and AdS soliton spacetimes, all the static solutions possess naked singularities. The time-dependent solutions can be regarded as the AdS extension of the well-known Kasner solutions. The speciality of those static regular solutions and the implication of singular solutions are also discussed in the context of cylindrical matter collapse. For the case of positive cosmological constant, the Kasner-de Sitter spacetime appears as time-dependent solutions and all static solutions are found to be naked singular.

  9. Restoration of four-dimensional diffeomorphism covariance in canonical general relativity: An intrinsic Hamilton-Jacobi approach

    Science.gov (United States)

    Salisbury, Donald; Renn, Jürgen; Sundermeyer, Kurt

    2016-02-01

    Classical background independence is reflected in Lagrangian general relativity through covariance under the full diffeomorphism group. We show how this independence can be maintained in a Hamilton-Jacobi approach that does not accord special privilege to any geometric structure. Intrinsic space-time curvature-based coordinates grant equal status to all geometric backgrounds. They play an essential role as a starting point for inequivalent semiclassical quantizations. The scheme calls into question Wheeler’s geometrodynamical approach and the associated Wheeler-DeWitt equation in which 3-metrics are featured geometrical objects. The formalism deals with variables that are manifestly invariant under the full diffeomorphism group. Yet, perhaps paradoxically, the liberty in selecting intrinsic coordinates is precisely as broad as is the original diffeomorphism freedom. We show how various ideas from the past five decades concerning the true degrees of freedom of general relativity can be interpreted in light of this new constrained Hamiltonian description. In particular, we show how the Kuchař multi-fingered time approach can be understood as a means of introducing full four-dimensional diffeomorphism invariants. Every choice of new phase space variables yields new Einstein-Hamilton-Jacobi constraining relations, and corresponding intrinsic Schrödinger equations. We show how to implement this freedom by canonical transformation of the intrinsic Hamiltonian. We also reinterpret and rectify significant work by Dittrich on the construction of “Dirac observables.”

  10. The finite-size scaling study of four-dimensional Ising model in the presence of external magnetic field

    Science.gov (United States)

    Merdan, Ziya; Kürkçü, Cihan; Öztürk, Mustafa K.

    2014-12-01

    The four-dimensional ferromagnetic Ising model in external magnetic field is simulated on the Creutz cellular automaton algorithm using finite-size lattices with linear dimension 4 ≤ L ≤ 8. The critical temperature value of infinite lattice, Tc χ ( ∞ ) = 6 , 680 (1) obtained for h = 0 agrees well with the values T c ( ∞ ) ≈ 6.68 obtained previously using different methods. Moreover, h = 0.00025 in our work also agrees with all the results obtained from h = 0 in the literature. However, there are no works for h ≠ 0 in the literature. The value of the field critical exponent (δ = 3.0136(3)) is in good agreement with δ = 3 which is obtained from scaling law of Widom. In spite of the finite-size scaling relations of | M L ( t ) | and χ L ( t ) for 0 ≤ h ≤ 0.001 are verified; however, in the cases of 0.0025 ≤ h ≤ 0.1 they are not verified.

  11. An Alternative View of the Universe Structure (on the invalidity of the four dimensional space-time concept)

    CERN Document Server

    Hovsepian, Felix

    2007-01-01

    The model of the Universe in this paper uses equations of the unperturbed Keplerian motion. They have been updated, complementied and generalized when the solution of these equations is the characteristic function of a random value from the theory of probabilities. Argument of the differential equation in this case is any more time, an interval of time between sections of a random stationary prosess. In this paper this time interval is referred to as flexible (elastic) time due to its many non-trivial properties. It is proved flexible time does not depend on the space which makes invalid the four dimensional space-time concept. The Universe becomes stationary and Eucledian. It is proved: 1. the advavce of Mercury's perihelion versus the predictions in accordance with the universal gravity law results inequality of the coefficients in the correlation equations of Keplerian moution along axes x, y and z; 2. the velocity of propagation of harmonic oscillation in the Uneverse is not constant; 3. long-range intera...

  12. Quantification of left and right atrial kinetic energy using four-dimensional intracardiac magnetic resonance imaging flow measurements.

    Science.gov (United States)

    Arvidsson, Per M; Töger, Johannes; Heiberg, Einar; Carlsson, Marcus; Arheden, Håkan

    2013-05-15

    Kinetic energy (KE) of atrial blood has been postulated as a possible contributor to ventricular filling. Therefore, we aimed to quantify the left (LA) and right (RA) atrial blood KE using cardiac magnetic resonance (CMR). Fifteen healthy volunteers underwent CMR at 3 T, including a four-dimensional phase-contrast flow sequence. Mean LA KE was lower than RA KE (1.1 ± 0.1 vs. 1.7 ± 0.1 mJ, P energy better than nonrotational flow did. The KE increase in early diastole was higher in the LA (P < 0.001). Systolic KE correlated with the combination of atrial volume and systolic velocity of the atrioventricular plane displacement (r(2) = 0.57 for LA and r(2) = 0.64 for RA). Early diastolic KE of the LA correlated with left ventricle (LV) mass (r(2) = 0.28), however, no such correlation was found in the right heart. This suggests that LA KE increases during early ventricular diastole due to LV elastic recoil, indicating that LV filling is dependent on diastolic suction. Right ventricle (RV) relaxation does not seem to contribute to atrial KE. Instead, RA KE generated during ventricular systole may be conserved in a hydraulic "flywheel" and transferred to the RV through helical flow, which may contribute to RV filling.

  13. Four-Dimensional Variational Data Assimilation Experiments for a Heavy Rain Case During the 2002 IOP in China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lin; NI Yunqi

    2005-01-01

    A heavy rainfall event along the mei-yu front during 22-23 June 2002 was chosen for this study. To assess the impact of the routine and additional IOP (intensive observation period) radiosonde observations on the mesoscale heavy rainfall forecast, a series of four-dimensional variational (4DVAR) data assimilation and model simulation experiments was conducted using nonhydrostatic mesoscale model MM5 and the MM5 4DVAR system. The effects of the intensive observations in the different areas on the heavy rainfall forecast were also investigated. The results showed that improvement of the forecast skill for mesoscale heavy rainfall intensity was possible from the assimilation of the IOP radiosonde observations. However,the impact of the IOP observations on the forecast of the rainfall pattern was not significant. Initial conditions obtained through the 4DVAR experiments with a 12-h assimilation window were capable of improving the 24-h forecast. The simulated results after the assimilation showed that it would be best to perform the intensive radiosonde observations in the upstream of the rainfall area and in the moisture passageway area at the same time. Initial conditions created by the 4DVAR led to the low-level moisture convergence over the rainfall area, enhanced frontogenesis and upward motion within the mei-yu front,and intensified middle- and high-level unstable stratification in front of the mei-yu front. Consequently,the heavy rainfall forecast was improved.

  14. Four-dimensional Cone Beam CT Reconstruction and Enhancement using a Temporal Non-Local Means Method

    CERN Document Server

    Jia, Xun; Lou, Yifei; Sonke, Jan-Jakob; Jiang, Steve B

    2012-01-01

    Four-dimensional Cone Beam Computed Tomography (4D-CBCT) has been developed to provide respiratory phase resolved volumetric imaging in image guided radiation therapy (IGRT). Inadequate number of projections in each phase bin results in low quality 4D-CBCT images with obvious streaking artifacts. In this work, we propose two novel 4D-CBCT algorithms: an iterative reconstruction algorithm and an enhancement algorithm, utilizing a temporal nonlocal means (TNLM) method. We define a TNLM energy term for a given set of 4D-CBCT images. Minimization of this term favors those 4D-CBCT images such that any anatomical features at one spatial point at one phase can be found in a nearby spatial point at neighboring phases. 4D-CBCT reconstruction is achieved by minimizing a total energy containing a data fidelity term and the TNLM energy term. As for the image enhancement, 4D-CBCT images generated by the FDK algorithm are enhanced by minimizing the TNLM function while keeping the enhanced images close to the FDK results. A...

  15. Fluctuation in measurements of pulmonary nodule under tidal volume ventilation on four-dimensional computed tomography: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Tateishi, Ukihide [National Cancer Center Hospital, Division of Diagnostic Radiology, Chuo-ku, Tokyo (Japan); Tsukagoshi, Shinsuke; Inokawa, Hiroyasu; Okumura, Miwa [Toshiba Medical Systems Corporation, CT Systems Development, Otawara (Japan); Moriyama, Noriyuki [National Cancer Center, Division of Cancer Screening, Research Center for Cancer Prevention and Screening, Tokyo (Japan)

    2008-10-15

    The present study aimed to assess the feasibility of four-dimensional (4D) chest computed tomography (CT) under tidal volume ventilation and the impact of respiratory motion on quantitative analysis of CT measurements. Forty-four pulmonary nodules in patients with metastatic disease were evaluated. CT examinations were performed using a 256 multidetector-row CT (MDCT) unit. Volume data were obtained from the lower lung fields (128 mm) above the diaphragm during dynamic CT acquisition. The CT parameters used were 120 kV, 100 or 150 mA, 0.5 s{sup -1}, and 0.5 mm collimation. Image data were reconstructed every 0.1 s during one respiratory cycle by a 180 reconstruction algorithm for four independent fractions of the respiratory cycle. Pulmonary nodules were measured along their longest and shortest axes using electronic calipers. Automated volumetry was assessed using commercially available software. The diameters of long and short axes in each frame were 9.0-9.6 mm and 7.1-7.5 mm, respectively. There was fluctuation of the long axis diameters in the third fraction. The mean volume in each fraction ranged from 365 to 394 mm{sup 3}. Statistically significant fluctuation was also found in the third fraction. 4D-CT under tidal volume ventilation is feasible to determine diameter or volume of the pulmonary nodule. (orig.)

  16. Four-dimensional cardiac reconstruction from rotational x-ray sequences: first results for 4D coronary angiography

    Science.gov (United States)

    Hansis, Eberhard; Schomberg, Hermann; Erhard, Klaus; Dössel, Olaf; Grass, Michael

    2009-02-01

    The tomographic reconstruction of the beating heart requires dedicated methods. One possibility is gated reconstruction, where only data corresponding to a certain motion state are incorporated. Another one is motioncompensated reconstruction with a pre-computed motion vector field, which requires a preceding estimation of the motion. Here, results of a new approach are presented: simultaneous reconstruction of a three-dimensional object and its motion over time, yielding a fully four-dimensional representation. The object motion is modeled by a time-dependent elastic transformation. The reconstruction is carried out with an iterative gradient-descent algorithm which simultaneously optimizes the three-dimensional image and the motion parameters. The method was tested on a simulated rotational X-ray acquisition of a dynamic coronary artery phantom, acquired on a C-arm system with a slowly rotating C-arm. Accurate reconstruction of both absorption coefficient and motion could be achieved. First results from experiments on clinical rotational X-ray coronary angiography data are shown. The resulting reconstructions enable the analysis of both static properties, such as vessel geometry and cross-sectional areas, and dynamic properties, like magnitude, speed, and synchrony of motion during the cardiac cycle.

  17. Generation and visualization of four-dimensional MR angiography data using an undersampled 3-D projection trajectory.

    Science.gov (United States)

    Liu, Jing; Redmond, Michael J; Brodsky, Ethan K; Alexander, Andrew L; Lu, Aiming; Thornton, Francis J; Schulte, Michael J; Grist, Thomas M; Pipe, James G; Block, Walter F

    2006-02-01

    Time-resolved contrast-enhanced magnetic resonance (MR) angiography (CE-MRA) has gained in popularity relative to X-ray Digital Subtraction Angiography because it provides three-dimensional (3-D) spatial resolution and it is less invasive. We have previously presented methods that improve temporal resolution in CE-MRA while providing high spatial resolution by employing an undersampled 3-D projection (3D PR) trajectory. The increased coverage and isotropic resolution of the 3D PR acquisition simplify visualization of the vasculature from any perspective. We present a new algorithm to develop a set of time-resolved 3-D image volumes by preferentially weighting the 3D PR data according to its acquisition time. An iterative algorithm computes a series of density compensation functions for a regridding reconstruction, one for each time frame, that exploit the variable sampling density in 3D PR. The iterative weighting procedure simplifies the calculation of appropriate density compensation for arbitrary sampling patterns, which improve sampling efficiency and, thus, signal-to-noise ratio and contrast-to-noise ratio, since it is does not require a closed-form calculation based on geometry. Current medical workstations can display these large four-dimensional studies, however, interactive cine animation of the data is only possible at significantly degraded resolution. Therefore, we also present a method for interactive visualization using powerful graphics cards and distributed processing. Results from volunteer and patient studies demonstrate the advantages of dynamic imaging with high spatial resolution.

  18. The effects of discontinuities in the Betts Miller cumulus convection scheme on four-dimensional variational data assimilation

    Science.gov (United States)

    Zupanski, Dušanka

    1993-10-01

    A tangent linear and an adjoint of the large-scale precipitation and the cumulus convection processes in the National Meteorological Center's NMC/ETA regional forecast model are developed. The effects of discontinuities in the Betts Miller cumulus convection scheme are examined and applicability of derivative minimization methods in four-dimensional variational (4D VAR) data assimilation is considered. It is demonstrated that discontinuities present in the control Betts Miller cumulus convection scheme increase linearization errors to a large extent and have adverse effects on 4D VAR data assimilation. In the experiments performed, discontinuities in the cumulus convection scheme have the most serious effect in low layers. These problems can be reduced by modifying the scheme to make it more continuous in low layers. Positive effects of inclusion of cumulus convection in 4D VAR data assimilation are found in upper layers, especially in humidity fields. The "observations" used are optimal interpolation analyses of temperature, surface pressure, wind and specific humidity. By inclusion of other data, more closely related to the convective processes, such as precipitation and clouds, more benefits should be expected. Even with the difficulties caused by discontinuities, derivative minimization techniques appear to work for the data assimilation problems. In order to get more general conclusions, more experiments are needed with different synoptic situations. The inclusion of other important physical processes such as radiation, surface friction and turbulence in the forecast and the corresponding adjoint models could alter the results since they may reinforce the effects of discontinuities.

  19. Validation of the four-dimensional symptom questionnaire (4DSQ) and prevalence of psychological symptoms in orthopedic shoulder patients.

    Science.gov (United States)

    Koorevaar, Rinco C T; Terluin, Berend; van 't Riet, Esther; Madden, Kim; Bulstra, Sjoerd K

    2016-04-01

    Psychological problems are common in shoulder patients. A validated psychological questionnaire measuring clinically relevant psychological symptoms (including distress, depression, anxiety, and somatization) in shoulder patients is lacking. The Four-Dimensional Symptom Questionnaire (4DSQ) is a self-report questionnaire to identify distress, depression, anxiety, and somatization which has been validated in primary care populations. The aim of this study was to validate the 4DSQ in orthopedic shoulder patients. We assessed whether the 4DSQ measures these four constructs the same way in an orthopedic population with shoulder problems compared to a general practice population. We also investigated the prevalence of psychological symptoms in shoulder patients. The shoulder group consisted of 200 consecutive patients and the general practice group comprised 368 patients, matched for gender and age. Differential item functioning analysis showed that the 4DSQ measures the different psychological symptoms in orthopedic shoulder patients the same way as in general practice patients. The shoulder patients tended to score higher on the somatization scale, resulting in a new cut-off point for somatization. The prevalence of distress, somatization, anxiety, and depression in the shoulder group was 23%, 14%, 10%, and 8%, respectively. It can be concluded from this study that the 4DSQ in orthopedic shoulder patients measures the same constructs as in general practice patients and can therefore be used in orthopedic practice to measure psychological symptoms in patients with shoulder complaints.

  20. Fast and exact method for computing a stack of images at various focuses from a four-dimensional light field

    Science.gov (United States)

    Mhabary, Ziv; Levi, Ofer; Small, Eran; Stern, Adrian

    2016-07-01

    This paper presents an efficient method for computing a stack of images digitally focused at various lengths from a four-dimensional light field (LF). The main contribution of this work is a fast and algebraically exact method that does not require interpolation in the frequency or spatial domains as alternative methods do. The proposed imaging operator combines two-dimensional (2-D) fast Fourier transform with 2-D fractional Fourier transform and has computational complexity of O(N log N), where N is the number of pixels in the LF tesseract of dimension N=nx×ny×nu×nv. The whole method consists of unitary vector-based operations; therefore, parallel implementation is easy and can contribute additional speed up. While current state of the art methods suffer from inherent tradeoff between the reconstruction quality and computational complexity, the proposed method benefits of both low-computational complexity and high-reconstruction quality. We also offer a solution for refocusing at distances that are not included in the reconstructed images stack. For such a case, we provide a modified version of our method, which is also algebraically exact and has lower computational complexity than other exact methods.

  1. Inflow hemodynamics evaluated by using four-dimensional flow magnetic resonance imaging and the size ratio of unruptured cerebral aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Futami, Kazuya [Matto-Ishikawa Central Hospital, Department of Neurosurgery, Hakusan, Ishikawa (Japan); Nambu, Iku; Kitabayashi, Tomohiro; Sano, Hiroki; Misaki, Kouichi; Uchiyama, Naoyuki; Nakada, Mitsutoshi [Kanazawa University School of Medicine, Department of Neurosurgery, Kanazawa, Ishikawa (Japan)

    2017-04-15

    Prediction of the rupture risk is critical for the identification of unruptured cerebral aneurysms (UCAs) eligible for invasive treatments. The size ratio (SR) is a strong morphological predictor for rupture. We investigated the relationship between the inflow hemodynamics evaluated on four-dimensional (4D) flow magnetic resonance (MR) imaging and the SR to identify specific characteristics related to UCA rupture. We evaluated the inflow jet patterns and inflow hemodynamic parameters of 70 UCAs on 4D flow MR imaging and compared them among 23 aneurysms with an SR ≥2.1 and 47 aneurysms with an SR ≤2.0. Based on the shape of inflow streamline bundles with a velocity ≥75% of the maximum flow velocity in the parent artery, the inflow jet patterns were classified as concentrated (C), diffuse (D), neck-limited (N), and unvisualized (U). The incidence of patterns C and N was significantly higher in aneurysms with an SR ≥2.1. The rate of pattern U was significantly higher in aneurysms with an SR ≤2.0. The maximum inflow rate and the inflow rate ratio were significantly higher in aneurysms with an SR ≥2.1. The SR affected the inflow jet pattern, the maximum inflow rate, and the inflow rate ratio of UCAs. In conjunction with the SR, inflow hemodynamic analysis using 4D flow MR imaging may contribute to the risk stratification for aneurysmal rupture. (orig.)

  2. Four-Dimensional (4D) Printing: A New Evolution in Computed Tomography-Guided Stereolithographic Modeling. Principles and Application.

    Science.gov (United States)

    Chae, Michael P; Hunter-Smith, David J; De-Silva, Inoka; Tham, Stephen; Spychal, Robert T; Rozen, Warren Matthew

    2015-07-01

    Over the last decade, image-guided production of three-dimensional (3D) haptic biomodels, or rapid prototyping (RP), has transformed the way surgeons conduct preoperative planning. In contrast to earlier RP techniques such as stereolithography, 3D printing has introduced fast, affordable office-based manufacturing. We introduce the concept of 4D printing for the first time by introducing time as the fourth dimension to 3D printing. The bones of the thumb ray are 3D printed during various movements to demonstrate four-dimensional (4D) printing. Principles and validation studies are presented here. 4D computed tomography was performed using "single volume acquisition" technology to reduce the exposure to radiation. Three representative scans of each thumb movement (i.e., abduction, opposition, and key pinch) were selected and then models were fabricated using a 3D printer. For validation, the angle between the first and the second metacarpals from the 4D imaging data and the 4D-printed model was recorded and compared. We demonstrate how 4D printing accurately depicts the transition in the position of metacarpals during thumb movement. With a fourth dimension of time, 4D printing delivers complex spatiotemporal anatomical details effortlessly and may substantially improve preoperative planning. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  3. Four-dimensional (4D) Motion Detection to Correct Respiratory Effects in Treatment Response Assessment Using Molecular Imaging Biomarkers

    Science.gov (United States)

    Schreibmann, Eduard; Crocker, Ian; Schuster, David M.; Curran, Walter J.; Fox, Tim

    2014-01-01

    Observing early metabolic changes in positron emission tomography (PET) is an essential tool to assess treatment efficiency in radiotherapy. However, for thoracic regions, the use of three-dimensional (3D) PET imaging is unfeasible because the radiotracer activity is smeared by the respiratory motion and averaged during the imaging acquisition process. This motion-induced degradation is similar in magnitude with the treatment-induced changes, and the two occurrences become indiscernible. We present a customized temporal-spatial deformable registration method for quantifying respiratory motion in a four-dimensional (4D) PET dataset. Once the motion is quantified, a motion-corrected (MC) dataset is created by tracking voxels to eliminate breathing-induced changes in the 4D imaging scan. The 4D voxel-tracking data is then summed to yield a 3D MC-PET scan containing only treatment-induced changes. This proof of concept is exemplified on both phantom and clinical data, where the proposed algorithm tracked the trajectories of individual points through the 4D datasets reducing motion to less than 4 mm in all phases. This correction approach using deformable registration can discern motion blurring from treatment-induced changes in treatment response assessment using PET imaging. PMID:24000982

  4. A novel color image encryption algorithm based on genetic recombination and the four-dimensional memristive hyperchaotic system

    Science.gov (United States)

    Chai, Xiu-Li; Gan, Zhi-Hua; Lu, Yang; Zhang, Miao-Hui; Chen, Yi-Ran

    2016-10-01

    Recently, many image encryption algorithms based on chaos have been proposed. Most of the previous algorithms encrypt components R, G, and B of color images independently and neglect the high correlation between them. In the paper, a novel color image encryption algorithm is introduced. The 24 bit planes of components R, G, and B of the color plain image are obtained and recombined into 4 compound bit planes, and this can make the three components affect each other. A four-dimensional (4D) memristive hyperchaotic system generates the pseudorandom key streams and its initial values come from the SHA 256 hash value of the color plain image. The compound bit planes and key streams are confused according to the principles of genetic recombination, then confusion and diffusion as a union are applied to the bit planes, and the color cipher image is obtained. Experimental results and security analyses demonstrate that the proposed algorithm is secure and effective so that it may be adopted for secure communication. Project supported by the National Natural Science Foundation of China (Grant Nos. 61203094 and 61305042), the Natural Science Foundation of the United States (Grant Nos. CNS-1253424 and ECCS-1202225), the Science and Technology Foundation of Henan Province, China (Grant No. 152102210048), the Foundation and Frontier Project of Henan Province, China (Grant No. 162300410196), the Natural Science Foundation of Educational Committee of Henan Province, China (Grant No. 14A413015), and the Research Foundation of Henan University, China (Grant No. xxjc20140006).

  5. Measurement of the transverse four-dimensional beam rms-emittance of an intense uranium beam at 11.4 MeV/u

    Science.gov (United States)

    Xiao, C.; Groening, L.; Gerhard, P.; Maier, M.; Mickat, S.; Vormann, H.

    2016-06-01

    Knowledge of the transverse four-dimensional beam rms-parameters is essential for applications that involve lattice elements that couple the two transverse degrees of freedom (planes). Usually pepper-pots are used for measuring these beam parameters. However, for ions their application is limited to energies below 150 keV/u. This contribution is on measurements of the full transverse four-dimensional second-moments beam matrix of high intensity uranium ions at an energy of 11.4 MeV/u. The combination of skew quadrupoles with a slit/grid emittance measurement device has been successfully applied.

  6. The echocardiography of replacement heart valves

    Science.gov (United States)

    2016-01-01

    This is a practical description of how replacement valves are assessed using echocardiography. Normal transthoracic appearances including normal variants are described. The problem of differentiating normal function, patient–prosthesis mismatch and pathological obstruction in aortic replacement valves with high gradients is discussed. Obstruction and abnormal regurgitation is described for valves in the aortic, mitral and right-sided positions and when to use echocardiography in suspected infective endocarditis. The roles of transoesophageal and stress echocardiography are described and finally when other imaging techniques may be useful. PMID:27600454

  7. Four Dimensional CO2 Data Assimilation of GOSAT Observation Data Using a Local Ensemble Transform Kalman Filter (LETKF)

    Science.gov (United States)

    Maki, T.; Sekiyama, T. T.; Miyoshi, T.; Nakamura, T.; Iwasaki, T.

    2015-12-01

    Impacts of CO2 concentration data obtained from satellite (GOSAT TIR L2 Ver. 1.0) measurements on the estimation of global surface CO2 fluxes have been investigated using an ensemble-based four-dimensional data assimilation system (LETKF). An online atmospheric transport model (MJ98-CDTM) is employed in the data assimilation system to optimize surface CO2 fluxes from real observations at spatial and temporal resolutions of 6 days and about 2.8° (T42), respectively. The features of GOSAT TIR L2 Ver. 1.0 data are their larger data number than that of SWIR L2 (about 10 times) and smaller standard deviation than their former version (TIR L2 Ver. 0.01). These points are the advantageous features to CO2 data assimilation. One of the most important issues in satellite data assimilation is a bias correction technique. Therefore, we have tested 4 types of satellite bias correction experiments (w/o bias correction, monthly mean bias correction, all data bias correction and globally constant bias correction) using independent CO2 concentration analysis (JMA CO2 distribution) in our data assimilation system. Our results showed that estimated CO2 concentration and fluxes are significantly sensitive to bias correction scheme. The reason may come from that model biases are important issue on data assimilation. In conclusion, suitable satellite data bias correction allows obtaining realistic CO2 concentration field and modifying surface CO2 flux almost entire earth surface. In addition, this satellite bias correction scheme makes it possible to use multiple satellite observation data simultaneously in CO2 data assimilation.

  8. Scapholunate kinematics of asymptomatic wrists in comparison with symptomatic contralateral wrists using four-dimensional CT examinations: initial clinical experience

    Energy Technology Data Exchange (ETDEWEB)

    Demehri, Shadpour; Hafezi-Nejad, Nima; Morelli, John N.; Thakur, Uma; Eng, John [Johns Hopkins University, Musculoskeletal Radiology, Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); Lifchez, Scott D.; Shores, Jaimie T. [Johns Hopkins University, Department of Plastic and Reconstructive Surgery, Baltimore, MD (United States); Means, Kenneth R. [MedStar Union Memorial Hospital, The Curtis National Hand Center, Baltimore, MD (United States)

    2016-04-15

    Using four-dimensional CT scan (4DCT), we aimed at showing the kinematics of scapholunate (SL) interval in asymptomatic wrists in comparison with symptomatic contralateral wrists with inconclusive radiographic findings. This is an IRB approved, HIPPA compliant, retrospective study. Patients suspected of SL interosseous ligament (SLIL) injuries were referred for further evaluation of chronic wrist pain (>3 months). Twelve wrists (11 subjects) with chronic symptoms and inconclusive plain radiographs and 10 asymptomatic wrists (in 10 different subjects) were scanned using 4DCT. The minimum SL interval was measured during three wrist motions: relaxed-to-clenched fist, flexion-to-extension, and radial-to-ulnar-deviation. Changes were recorded using double-oblique multiplanar reformation technique. We extracted the normal limits of the SL interval as measured by dynamic CT scanning during active motion in asymptomatic wrists. In asymptomatic wrists, the average SL interval was observed to be smaller than 1 mm during all motions. In symptomatic wrists, during exams performed with clenched fist (SL interval (mean ± SD) = 2.53 ± 1.19 mm), extension (2.54 ± 1.48 mm) or ulnar deviation (2.06 ± 1.12 mm), the average SL interval was more than 2 mm. In contrast to symptomatic wrists, no significant change in SL interval measurements was detected during wrist motions in asymptomatic wrists. There was a mild to moderate correlation between SL interval change and presence/absence of symptoms (point-biserial correlation coefficients: 0.29-0.55). In patients with wrist pain suspicious for SLIL injury and inconclusive radiographs, SL interval increase can be detected with 4DCT in the symptomatic wrist compared to the asymptomatic wrist. (orig.)

  9. A four-dimensional motion field atlas of the tongue from tagged and cine magnetic resonance imaging

    Science.gov (United States)

    Xing, Fangxu; Prince, Jerry L.; Stone, Maureen; Wedeen, Van J.; El Fakhri, Georges; Woo, Jonghye

    2017-02-01

    Representation of human tongue motion using three-dimensional vector fields over time can be used to better understand tongue function during speech, swallowing, and other lingual behaviors. To characterize the inter-subject variability of the tongue's shape and motion of a population carrying out one of these functions it is desirable to build a statistical model of the four-dimensional (4D) tongue. In this paper, we propose a method to construct a spatio-temporal atlas of tongue motion using magnetic resonance (MR) images acquired from fourteen healthy human subjects. First, cine MR images revealing the anatomical features of the tongue are used to construct a 4D intensity image atlas. Second, tagged MR images acquired to capture internal motion are used to compute a dense motion field at each time frame using a phase-based motion tracking method. Third, motion fields from each subject are pulled back to the cine atlas space using the deformation fields computed during the cine atlas construction. Finally, a spatio-temporal motion field atlas is created to show a sequence of mean motion fields and their inter-subject variation. The quality of the atlas was evaluated by deforming cine images in the atlas space. Comparison between deformed and original cine images showed high correspondence. The proposed method provides a quantitative representation to observe the commonality and variability of the tongue motion field for the first time, and shows potential in evaluation of common properties such as strains and other tensors based on motion fields.

  10. Dynamic measurement of the optical properties of bovine enamel demineralization models using four-dimensional optical coherence tomography

    Science.gov (United States)

    Aden, Abdirahman; Anthony, Arthi; Brigi, Carel; Merchant, Muhammad Sabih; Siraj, Huda; Tomlins, Peter H.

    2017-07-01

    Dental enamel mineral loss is multifactorial and is consequently explored using a variety of in vitro models. Important factors include the presence of acidic pH and its specific ionic composition, which can both influence lesion characteristics. Optical coherence tomography (OCT) has been demonstrated as a promising tool for studying dental enamel demineralization. However, OCT-based characterization and comparison of demineralization model dynamics are challenging without a consistent experimental environment. Therefore, an automated four-dimensional OCT system was integrated with a multispecimen flow cell to measure and compare the optical properties of subsurface enamel demineralization in different models. This configuration was entirely automated, thus mitigating any need to disturb the specimens and ensuring spatial registration of OCT image volumes at multiple time points. Twelve bovine enamel disks were divided equally among three model groups. The model demineralization solutions were citric acid (pH 3.8), acetic acid (pH 4.0), and acetic acid with added calcium and phosphate (pH 4.4). Bovine specimens were exposed to the solution continuously for 48 h. Three-dimensional OCT data were obtained automatically from each specimen at a minimum of 1-h intervals from the same location within each specimen. Lesion dynamics were measured in terms of the depth below the surface to which the lesion extended and the attenuation coefficient. The net loss of surface enamel was also measured for comparison. Similarities between the dynamics of each model were observed, although there were also distinct characteristic differences. Notably, the attenuation coefficients showed a systematic offset and temporal shift with respect to the different models. Furthermore, the lesion depth curves displayed a discontinuous increase several hours after the initial acid challenge. This work demonstrated the capability of OCT to distinguish between different enamel demineralization

  11. Dissipation of the tilting degree of freedom in heavy-ion-induced fission from four-dimensional Langevin dynamics

    Science.gov (United States)

    Nadtochy, P. N.; Ryabov, E. G.; Cheredov, A. V.; Adeev, G. D.

    2016-10-01

    A stochastic approach based on four-dimensional Langevin fission dynamics is applied to the calculation of a wide set of experimental observables of excited compound nuclei from 199Pb to 248Cf formed in reactions induced by heavy ions. In the model under investigation, the tilting degree of freedom ( K coordinate) representing the projection of the total angular momentum onto the symmetry axis of the nucleus is taken into account in addition to three collective shape coordinates introduced on the basis of {c,h,α} parametrization. The evolution of the K coordinate is described by means of the Langevin equation in the overdamped regime. The friction tensor for the shape collective coordinates is calculated under the assumption of the modified version of the one-body dissipation mechanism, where the reduction coefficient ks of the contribution from the "wall" formula is introduced. The calculations are performed both for the constant values of the coefficient ks and for the coordinate-dependent reduction coefficient ks(q) which is found on the basis of the "chaos-weighted wall formula". Different possibilities of the deformation-dependent dissipation coefficient (γK) for the K coordinate are investigated. The presented results demonstrate that an impact of the ks and γK parameters on the calculated observable fission characteristics can be selectively probed. It was found that it is possible to describe the experimental data consistently with the deformation-dependent γK(q) coefficient for shapes featuring a neck, which predicts quite small values of γK=0.0077 (MeV zs)-1/2 and constant γK=0.1-0.4 (MeV zs)-1/2 for compact shapes featuring no neck.

  12. Detecting cause of dislocation after total hip arthroplasty by patient-specific four-dimensional motion analysis.

    Science.gov (United States)

    Miki, Hidenobu; Sugano, Nobuhiko; Yonenobu, Kazuo; Tsuda, Kosuke; Hattori, Maki; Suzuki, Naoki

    2013-02-01

    Dislocation is a major complication after total hip arthroplasty. Prosthesis impingement is considered to be an important cause of dislocation because impingement marks are more frequently found on retrieved cups or liners in patients who have undergone revision surgery because of dislocation (80%-94%) than in those who have undergone reoperation for other reasons (51%-56%). However, it remains a question whether impingement marks are the cause of dislocation or are instead its result. To clarify the issue, it is necessary to confirm noninvasively whether the point of impingement matches the patient's hip position when dislocation occurs. Using four-dimensional patient-specific analysis, we recorded prosthesis impingement in 10 hips with instability after primary total hip arthroplasty when the patients reproduced the dislocation-causing motion. We found prosthesis impingement to be related to at least instability in 6 of 10 hips with dislocation after primary total hip arthroplasty and in 4 of 4 hips that underwent revision surgery for recurrent dislocation. All impingements occurred between the anterior wall of the liner and the stem neck in posterior dislocation and between the posterior wall of the liner and the stem neck in anterior dislocation. Revision surgery in 1 of those 4 hips revealed 2 impingement marks on the retrieved liner that closely matched the prosthesis impingement point and the dislocation pathway of the metal head on the liner that were detected earlier during motion analysis. Prosthesis impingement is an important factor in dislocation after total hip arthroplasty. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. To what extent does the anxiety scale of the Four-Dimensional Symptom Questionnaire (4DSQ) detect specific types of anxiety disorder in primary care? A psychometric study

    NARCIS (Netherlands)

    Terluin, B.; Oosterbaan, D.B.; Brouwers, E.P.; Straten, A. van; Ven, P.M. van de; Langerak, W.; Marwijk, H.W.J. van

    2014-01-01

    BACKGROUND: Anxiety scales may help primary care physicians to detect specific anxiety disorders among the many emotionally distressed patients presenting in primary care. The anxiety scale of the Four-Dimensional Symptom Questionnaire (4DSQ) consists of an admixture of symptoms of specific anxiety

  14. 四维彩超输卵管造影流程的规范与优化%Standardization and optimization of four-dimensional ultrasound hysterosalpinography process

    Institute of Scientific and Technical Information of China (English)

    杨曦; 张靖; 孟洁; 陈俊雅; 张潇潇; 汪京萍; 李琛; 郑潇潇; 白文佩

    2014-01-01

    In four-dimensional ultrasound hysterosalpinography micro bubble ultrasound contrast agent -sonovueis is injected into the uterine cavity to distend uterine cavity and fallopian for four-dimensional imaging .Four-dimensional ultrasound hysterosalpinography is mainly performed for the evaluation of uterine tubal patency and diagnosis of intrauterine lesions to analyze the causes of female infertility . It is accurate, safe, non-invasive, efficient and therapeutic.A detailed description of standard process of four-dimensional ultrasound hysterosalpinography was described in this paper .%四维彩超输卵管造影检查术是将微气泡超声造影剂———声诺维注入到宫腔,使原本闭合的宫腔和输卵管扩张,然后进行四维成像,主要用于评价输卵管通畅性和诊断子宫宫腔病变,用以诊断女性不孕的原因,具有准确、安全、无创伤、快捷及治疗作用。该文详细叙述了四维彩超输卵管造影的规范流程。

  15. The Hawking temperature in the context of dark energy for four-dimensional asymptotically AdS black holes with scalar hair

    Science.gov (United States)

    Naji, J.

    2016-01-01

    In this paper, we considered new solutions for four-dimensional asymptotically AdS black holes with scalar hair and discuss about Hawking temperature in the context of dark energy by using the tunneling method. We obtain modification of the Hawking temperature due to presence of the dark energy.

  16. Fetal echocardiography in ectopia cordis.

    Science.gov (United States)

    Repondek-Liberska, M; Janiak, K; Wloch, A

    2000-01-01

    Ectopia cordis is an extremely rare congenital abnormality occurring in 5.5 to 7.9 per 1 million live births with high lethality. Between January 1995 and October 1997 eight cases of ectopia cordis were diagnosed at our institute before birth. On the basis of echocardiography the fetal heart anatomy was categorized as either normal heart anatomy (NHA; n = 3) or congenital heart defect (CHD; n = 5). In the majority of cases (seven of eight) other abnormalities were present. Some reports have described ectopia cordis being diagnosed in the first trimester of pregnancy. In our study group the average gestational age at diagnosis was 26 weeks. The prenatal diagnosis of isolated ectopia cordis is easy; counseling the patient, the perinatal management including term, place, and method of delivery, and optimal care of the newborn are more difficult. Ectopia cordis is a malformation that pediatricians rarely encounter, even at pediatric cardiology centers. Much more frequently it is a problem for sonographers and obstetricians; however, pediatric cardiologists should be aware of diagnostic algorithm for such cases, especially when additional abnormalities are present.

  17. Transoesophageal echocardiography during liver transplantation

    Institute of Scientific and Technical Information of China (English)

    Lesley; De; Pietri; Federico; Mocchegiani; Chiara; Leuzzi; Roberto; Montalti; Marco; Vivarelli; Vanni; Agnoletti

    2015-01-01

    Liver transplantation(LT) has become the standard of care for patients with end stage liver disease. The allocation of organs, which prioritizes the sickest patients, has made the management of liver trans-plant candidates more complex both as regards their comorbidities and their higher risk of perioperative complications. Patients undergoing LT frequently display considerable physiological changes during the pro-cedures as a result of both the disease process and the surgery. Transoesophageal echocardiography(TEE), which visualizes dynamic cardiac function and overall contractility, has become essential for perioperative LT management and can optimize the anaesthetic management of these highly complex patients. More-over, TEE can provide useful information on volume status and the adequacy of therapeutic interventions and can diagnose early intraoperative complications, such as the embolization of large vessels or development of pulmonary hypertension. In this review, directed at clinicians who manage TEE during LT, we show why the procedure merits a place in challenging anaesthetic environment and how it can provide essential information in the perioperative management of compromised patients undergoing this very complex surgical procedure.

  18. Effect of tumor volume on the enhancement pattern of parathyroid adenoma on parathyroid four-dimensional CT

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Kyoung [Seoul National University Medical Research Center, Institute of Radiation Medicine, Seoul (Korea, Republic of); Dongguk University Ilsan Hospital, Department of Radiology, Goyang-si (Korea, Republic of); Yun, Tae Jin; Kim, Ji-hoon; Kang, Koung Mi; Choi, Seung Hong; Sohn, Chul-Ho [Seoul National University Medical Research Center, Institute of Radiation Medicine, Seoul (Korea, Republic of); Seoul National University Hospital, Department of Radiology, Jongno-gu, Seoul (Korea, Republic of); Lee, Kyu Eun; Kim, Su-jin [Seoul National University Hospital, Department of Surgery, Seoul (Korea, Republic of); Won, Jae-Kyung [Seoul National University Hospital, Department of Pathology, Seoul (Korea, Republic of)

    2016-05-15

    The purpose of this study is to assess the effect of tumor volume on the enhancement pattern of parathyroid adenoma (PTA) on four-dimensional computed tomography (4D-CT). We analyzed the enhancement patterns of PTA on four-phase 4D-CT in 44 patients. Dependency of the changes of Hounsfield unit values (ΔHU) on the tumor volumes and clinical characteristics was evaluated using linear regression analyses. In addition, an unpaired t test was used to compare ΔHU of PTAs between PTA volume ≥1 cm{sup 3} and <1 cm{sup 3}, thyroid gland, and lymph node. PTA volume based on CT was the strongest factor on the ΔHU{sub Pre} {sub to} {sub Arterial} and ΔHU{sub Arterial} {sub to} {sub Venous} and ΔHU{sub Arterial} {sub to} {sub Delayed} (R {sup 2} = 0.34, 0.25, and 0.32, respectively, P < 0.001 for both). PTA ≥1 cm {sup 3} had statistically significant greater enhancement between the unenhanced phase and the arterial phase than PTA <1 cm {sup 3} (mean values ± standard deviations (SDs) of ΔHU{sub Pre} {sub to} {sub Arterial}, 102.7 ± 33.7 and 57.5 ± 28.8, respectively, P < 0.001). PTA ≥1 cm {sup 3} showed an early washout pattern on the venous phase, whereas PTA <1 cm {sup 3} showed a progressive enhancement pattern on the venous phase (mean values ± SDs of ΔHU{sub Arterial} {sub to} {sub Venous}, -13.2 ± 31.6 and 14.4 ± 32.7, respectively; P = 0.009). The enhancement pattern of PTA on 4D-CT is variable with respect to PTA volume based on CT. Therefore, the enhancement pattern of PTA on 4D-CT requires careful interpretation concerning the tumor volume, especially in cases of PTA <1 cm {sup 3}. (orig.)

  19. SU-C-207-01: Four-Dimensional Inverse Geometry Computed Tomography: Concept and Its Validation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K; Kim, D; Kim, T; Kang, S; Cho, M; Shin, D; Suh, T [The Catholic University of Korea, Seoul (Korea, Republic of)

    2015-06-15

    Purpose: In past few years, the inverse geometry computed tomography (IGCT) system has been developed to overcome shortcomings of a conventional computed tomography (CT) system such as scatter problem induced from large detector size and cone-beam artifact. In this study, we intend to present a concept of a four-dimensional (4D) IGCT system that has positive aspects above all with temporal resolution for dynamic studies and reduction of motion artifact. Methods: Contrary to conventional CT system, projection data at a certain angle in IGCT was a group of fractionated narrow cone-beam projection data, projection group (PG), acquired from multi-source array which have extremely short time gap of sequential operation between each of sources. At this, for 4D IGCT imaging, time-related data acquisition parameters were determined by combining multi-source scanning time for collecting one PG with conventional 4D CBCT data acquisition sequence. Over a gantry rotation, acquired PGs from multi-source array were tagged time and angle for 4D image reconstruction. Acquired PGs were sorted into 10 phase and image reconstructions were independently performed at each phase. Image reconstruction algorithm based upon filtered-backprojection was used in this study. Results: The 4D IGCT had uniform image without cone-beam artifact on the contrary to 4D CBCT image. In addition, the 4D IGCT images of each phase had no significant artifact induced from motion compared with 3D CT. Conclusion: The 4D IGCT image seems to give relatively accurate dynamic information of patient anatomy based on the results were more endurable than 3D CT about motion artifact. From this, it will be useful for dynamic study and respiratory-correlated radiation therapy. This work was supported by the Industrial R&D program of MOTIE/KEIT [10048997, Development of the core technology for integrated therapy devices based on real-time MRI guided tumor tracking] and the Mid-career Researcher Program (2014R1A2A1A

  20. Improving thoracic four-dimensional cone-beam CT reconstruction with anatomical-adaptive image regularization (AAIR).

    Science.gov (United States)

    Shieh, Chun-Chien; Kipritidis, John; O'Brien, Ricky T; Cooper, Benjamin J; Kuncic, Zdenka; Keall, Paul J

    2015-01-21

    Total-variation (TV) minimization reconstructions can significantly reduce noise and streaks in thoracic four-dimensional cone-beam computed tomography (4D CBCT) images compared to the Feldkamp-Davis-Kress (FDK) algorithm currently used in practice. TV minimization reconstructions are, however, prone to over-smoothing anatomical details and are also computationally inefficient. The aim of this study is to demonstrate a proof of concept that these disadvantages can be overcome by incorporating the general knowledge of the thoracic anatomy via anatomy segmentation into the reconstruction. The proposed method, referred as the anatomical-adaptive image regularization (AAIR) method, utilizes the adaptive-steepest-descent projection-onto-convex-sets (ASD-POCS) framework, but introduces an additional anatomy segmentation step in every iteration. The anatomy segmentation information is implemented in the reconstruction using a heuristic approach to adaptively suppress over-smoothing at anatomical structures of interest. The performance of AAIR depends on parameters describing the weighting of the anatomy segmentation prior and segmentation threshold values. A sensitivity study revealed that the reconstruction outcome is not sensitive to these parameters as long as they are chosen within a suitable range. AAIR was validated using a digital phantom and a patient scan and was compared to FDK, ASD-POCS and the prior image constrained compressed sensing (PICCS) method. For the phantom case, AAIR reconstruction was quantitatively shown to be the most accurate as indicated by the mean absolute difference and the structural similarity index. For the patient case, AAIR resulted in the highest signal-to-noise ratio (i.e. the lowest level of noise and streaking) and the highest contrast-to-noise ratios for the tumor and the bony anatomy (i.e. the best visibility of anatomical details). Overall, AAIR was much less prone to over-smoothing anatomical details compared to ASD-POCS and did

  1. Four-dimensional distribution of the 2010 Eyjafjallajökull volcanic cloud over Europe observed by EARLINET

    Directory of Open Access Journals (Sweden)

    G. Pappalardo

    2012-11-01

    Full Text Available The eruption of the Icelandic volcano Eyjafjallajökull in April/May 2010 represents a "natural experiment" to study the impact of volcanic emissions on a continental scale. For the first time, quantitative data about the presence, altitude, and layering of the volcanic cloud, in conjunction with optical information, are available for most parts of Europe derived from the observations by the European Aerosol Research Lidar NETwork (EARLINET. Based on multi-wavelength Raman lidar systems EARLINET is the only instrument worldwide that is able to provide dense time series of high-quality optical data to be used for aerosol typing and for the retrieval of particle microphysical properties as a function of altitude.

    In this work we show the four-dimensional (4-D distribution of the Eyjafjallajökull volcanic cloud over Europe as observed by EARLINET during the entire volcanic event (15 April–26 May 2010. All optical properties directly measured (backscatter, extinction, and particle linear depolarization ratio are stored in the EARLINET database available at http://www.earlinet.org. A specific relational database providing the volcanic mask over Europe, realized ad hoc for this specific event, has been developed and is available on request at http://www.earlinet.org.

    During the first days after the eruption, volcanic particles were detected over Central Europe within a wide range of altitudes, from the lower stratosphere down to the local Planetary Boundary Layer (PBL. After 19 April 2010, volcanic particles were detected over South and South Eastern Europe. During the first half of May (5–15 May, material emitted by the Eyjafjallajökull volcano was detected over Spain and Portugal and then over the Mediterranean and the Balkans. Last observations of the event were recorded until 25 May in Central Europe and in the Eastern

  2. Comparison of planning target volumes based on three-dimensional and four-dimensional CT imaging of thoracic esophageal cancer.

    Science.gov (United States)

    Wang, Wei; Li, Jianbin; Zhang, Yingjie; Shao, Qian; Xu, Min; Fan, Tingyong; Wang, Jinzhi

    2016-01-01

    To investigate the definition of planning target volumes (PTVs) based on four-dimensional computed tomography (4DCT) compared with conventional PTV definition and PTV definition using asymmetrical margins for thoracic primary esophageal cancer. Forty-three patients with esophageal cancer underwent 3DCT and 4DCT simulation scans during free breathing. The motions of primary tumors located in the proximal (group A), middle (group B), and distal (group C) thoracic esophagus were obtained from the 4DCT scans. PTV3D was defined on 3DCT using the tumor motion measured based on 4DCT, PTV conventional (PTVconv) was defined on 3DCT by adding a 1.0 cm margin to the clinical target volume, and PTV4D was defined as the union of the target volumes contoured on the ten phases of the 4DCT images. The centroid positions, volumetric differences, and dice similarity coefficients were evaluated for all PTVs. The median centroid shifts between PTV3D and PTV4D and between PTVconv and PTV4D in all three dimensions were groups. The median size ratios of PTV4D to PTV3D were 0.80, 0.88, and 0.71, and PTV4D to PTVconv were 0.67, 0.73, and 0.76 (χ (2)=-3.18, -2.98, and -3.06; P=0.001, 0.003, and 0.002) for groups A, B, and C, respectively. The dice similarity coefficients were 0.87, 0.90, and 0.81 between PTV4D and PTV3D and 0.80, 0.84, and 0.83 between PTV4D and PTVconv (χ (2) =-3.18, -2.98, and -3.06; P=0.001, 0.003, and 0.002) for groups A, B, and C, respectively. The difference between the degree of inclusion of PTV4D in PTV3D and that of PTV4D in PTVconv was groups. Compared with PTVconv, the amount of irradiated normal tissue for PTV3D was decreased by 11.81% and 11.86% in groups A and B, respectively, but was increased by 2.93% in group C. For proximal and middle esophageal cancer, 3DCT-based PTV using asymmetrical margins provides good coverage of PTV4D; however, for distal esophageal cancer, 3DCT-based PTV using conventional margins provides ideal conformity with PTV4D.

  3. Hyperpolarized (3)He magnetic resonance imaging: comparison with four-dimensional x-ray computed tomography imaging in lung cancer.

    Science.gov (United States)

    Mathew, Lindsay; Wheatley, Andrew; Castillo, Richard; Castillo, Edward; Rodrigues, George; Guerrero, Thomas; Parraga, Grace

    2012-12-01

    Pulmonary functional imaging using four-dimensional x-ray computed tomographic (4DCT) imaging and hyperpolarized (3)He magnetic resonance imaging (MRI) provides regional lung function estimates in patients with lung cancer in whom pulmonary function measurements are typically dominated by tumor burden. The aim of this study was to evaluate the quantitative spatial relationship between 4DCT and hyperpolarized (3)He MRI ventilation maps. Eleven patients with lung cancer provided written informed consent to 4DCT imaging and MRI performed within 11 ± 14 days. Hyperpolarized (3)He MRI was acquired in breath-hold after inhalation from functional residual capacity of 1 L hyperpolarized (3)He, whereas 4DCT imaging was acquired over a single tidal breath of room air. For hyperpolarized (3)He MRI, the percentage ventilated volume was generated using semiautomated segmentation; for 4DCT imaging, pulmonary function maps were generated using the correspondence between identical tissue elements at inspiratory and expiratory phases to generate percentage ventilated volume. After accounting for differences in image acquisition lung volumes ((3)He MRI: 1.9 ± 0.5 L ipsilateral, 2.3 ± 0.7 L contralateral; 4DCT imaging: 1.2 ± 0.3 L ipsilateral, 1.3 ± 0.4 L contralateral), there was no significant difference in percentage ventilated volume between hyperpolarized (3)He MRI (72 ± 11% ipsilateral, 79 ± 12% contralateral) and 4DCT imaging (74 ± 3% ipsilateral, 75 ± 4% contralateral). Spatial correspondence between 4DCT and (3)He MRI ventilation was evaluated using the Dice similarity coefficient index (ipsilateral, 86 ± 12%; contralateral, 88 ± 12%). Despite rather large differences in image acquisition breathing maneuvers, good spatial and significant quantitative agreement was observed for ventilation maps on hyperpolarized (3)He MRI and 4DCT imaging, suggesting that pulmonary regions with good lung function are similar between modalities in this small group of patients with

  4. Four-dimensional variational inversion of black carbon emissions during ARCTAS-CARB with WRFDA-Chem

    Directory of Open Access Journals (Sweden)

    J. J. Guerrette

    2017-06-01

    Full Text Available Biomass burning emissions of atmospheric aerosols, including black carbon, are growing due to increased global drought, and comprise a large source of uncertainty in regional climate and air quality studies. We develop and apply new incremental four-dimensional variational (4D-Var capabilities in WRFDA-Chem to find optimal spatially and temporally distributed biomass burning (BB and anthropogenic black carbon (BC aerosol emissions. The constraints are provided by aircraft BC concentrations from the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites in collaboration with the California Air Resources Board (ARCTAS-CARB field campaign and surface BC concentrations from the Interagency Monitoring of PROtected Visual Environment (IMPROVE network on 22, 23, and 24 June 2008. We consider three BB inventories, including Fire INventory from NCAR (FINN v1.0 and v1.5 and Quick Fire Emissions Database (QFED v2.4r8. On 22 June, aircraft observations are able to reduce the spread between a customized QFED inventory and FINNv1.0 from a factor of 3. 5 ( × 3. 5 to only × 2. 1. On 23 and 24 June, the spread is reduced from × 3. 4 to × 1. 4. The posterior corrections to emissions are heterogeneous in time and space, and exhibit similar spatial patterns of sign for both inventories. The posterior diurnal BB patterns indicate that multiple daily emission peaks might be warranted in specific regions of California. The US EPA's 2005 National Emissions Inventory (NEI05 is used as the anthropogenic prior. On 23 and 24 June, the coastal California posterior is reduced by × 2, where highway sources dominate, while inland sources are increased near Barstow by × 5. Relative BB emission variances are reduced from the prior by up to 35 % in grid cells close to aircraft flight paths and by up to 60 % for fires near surface measurements. Anthropogenic variance reduction is as high as 40 % and is similarly

  5. Four-dimensional variational inversion of black carbon emissions during ARCTAS-CARB with WRFDA-Chem

    Science.gov (United States)

    Guerrette, Jonathan J.; Henze, Daven K.

    2017-06-01

    Biomass burning emissions of atmospheric aerosols, including black carbon, are growing due to increased global drought, and comprise a large source of uncertainty in regional climate and air quality studies. We develop and apply new incremental four-dimensional variational (4D-Var) capabilities in WRFDA-Chem to find optimal spatially and temporally distributed biomass burning (BB) and anthropogenic black carbon (BC) aerosol emissions. The constraints are provided by aircraft BC concentrations from the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites in collaboration with the California Air Resources Board (ARCTAS-CARB) field campaign and surface BC concentrations from the Interagency Monitoring of PROtected Visual Environment (IMPROVE) network on 22, 23, and 24 June 2008. We consider three BB inventories, including Fire INventory from NCAR (FINN) v1.0 and v1.5 and Quick Fire Emissions Database (QFED) v2.4r8. On 22 June, aircraft observations are able to reduce the spread between a customized QFED inventory and FINNv1.0 from a factor of 3. 5 ( × 3. 5) to only × 2. 1. On 23 and 24 June, the spread is reduced from × 3. 4 to × 1. 4. The posterior corrections to emissions are heterogeneous in time and space, and exhibit similar spatial patterns of sign for both inventories. The posterior diurnal BB patterns indicate that multiple daily emission peaks might be warranted in specific regions of California. The US EPA's 2005 National Emissions Inventory (NEI05) is used as the anthropogenic prior. On 23 and 24 June, the coastal California posterior is reduced by × 2, where highway sources dominate, while inland sources are increased near Barstow by × 5. Relative BB emission variances are reduced from the prior by up to 35 % in grid cells close to aircraft flight paths and by up to 60 % for fires near surface measurements. Anthropogenic variance reduction is as high as 40 % and is similarly limited to sources close to observations. We

  6. Four-dimensional dose reconstruction through in vivo phase matching of cine images of electronic portal imaging device.

    Science.gov (United States)

    Yoon, Jihyung; Jung, Jae Won; Kim, Jong Oh; Yi, Byong Yong; Yeo, Inhwan

    2016-07-01

    A method is proposed to reconstruct a four-dimensional (4D) dose distribution using phase matching of measured cine images to precalculated images of electronic portal imaging device (EPID). (1) A phantom, designed to simulate a tumor in lung (a polystyrene block with a 3 cm diameter embedded in cork), was placed on a sinusoidally moving platform with an amplitude of 1 cm and a period of 4 s. Ten-phase 4D computed tomography (CT) images of the phantom were acquired. A planning target volume (PTV) was created by adding a margin of 1 cm around the internal target volume of the tumor. (2) Three beams were designed, which included a static beam, a theoretical dynamic beam, and a planning-optimized dynamic beam (PODB). While the theoretical beam was made by manually programming a simplistic sliding leaf motion, the planning-optimized beam was obtained from treatment planning. From the three beams, three-dimensional (3D) doses on the phantom were calculated; 4D dose was calculated by means of the ten phase images (integrated over phases afterward); serving as "reference" images, phase-specific EPID dose images under the lung phantom were also calculated for each of the ten phases. (3) Cine EPID images were acquired while the beams were irradiated to the moving phantom. (4) Each cine image was phase-matched to a phase-specific CT image at which common irradiation occurred by intercomparing the cine image with the reference images. (5) Each cine image was used to reconstruct dose in the phase-matched CT image, and the reconstructed doses were summed over all phases. (6) The summation was compared with forwardly calculated 4D and 3D dose distributions. Accounting for realistic situations, intratreatment breathing irregularity was simulated by assuming an amplitude of 0.5 cm for the phantom during a portion of breathing trace in which the phase matching could not be performed. Intertreatment breathing irregularity between the time of treatment and the time of planning CT was

  7. Measuring interfraction and intrafraction lung function changes during radiation therapy using four-dimensional cone beam CT ventilation imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kipritidis, John, E-mail: john.kipritidis@sydney.edu.au; Keall, Paul J. [Radiation Physics Laboratory, Sydney Medical School, University of Sydney, Sydney NSW 2006 (Australia); Hugo, Geoffrey; Weiss, Elisabeth; Williamson, Jeffrey [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298 (United States)

    2015-03-15

    Purpose: Adaptive ventilation guided radiation therapy could minimize the irradiation of healthy lung based on repeat lung ventilation imaging (VI) during treatment. However the efficacy of adaptive ventilation guidance requires that interfraction (e.g., week-to-week), ventilation changes are not washed out by intrafraction (e.g., pre- and postfraction) changes, for example, due to patient breathing variability. The authors hypothesize that patients undergoing lung cancer radiation therapy exhibit larger interfraction ventilation changes compared to intrafraction function changes. To test this, the authors perform the first comparison of interfraction and intrafraction lung VI pairs using four-dimensional cone beam CT ventilation imaging (4D-CBCT VI), a novel technique for functional lung imaging. Methods: The authors analyzed a total of 215 4D-CBCT scans acquired for 19 locally advanced non-small cell lung cancer (LA-NSCLC) patients over 4–6 weeks of radiation therapy. This set of 215 scans was sorted into 56 interfraction pairs (including first day scans and each of treatment weeks 2, 4, and 6) and 78 intrafraction pairs (including pre/postfraction scans on the same-day), with some scans appearing in both sets. VIs were obtained from the Jacobian determinant of the transform between the 4D-CBCT end-exhale and end-inhale images after deformable image registration. All VIs were deformably registered to their corresponding planning CT and normalized to account for differences in breathing effort, thus facilitating image comparison in terms of (i) voxelwise Spearman correlations, (ii) mean image differences, and (iii) gamma pass rates for all interfraction and intrafraction VI pairs. For the side of the lung ipsilateral to the tumor, we applied two-sided t-tests to determine whether interfraction VI pairs were more different than intrafraction VI pairs. Results: The (mean ± standard deviation) Spearman correlation for interfraction VI pairs was r{sup -}{sub Inter

  8. Comparison of planning target volumes based on three-dimensional and four-dimensional CT imaging of thoracic esophageal cancer

    Directory of Open Access Journals (Sweden)

    Wang W

    2016-08-01

    Full Text Available Wei Wang, Jianbin Li, Yingjie Zhang, Qian Shao, Min Xu, Tingyong Fan, Jinzhi Wang Department of Radiation Oncology, Shandong Cancer Hospital Affiliated to Shandong University, Shandong Academy of Medical Sciences, Shandong, People’s Republic of China Background and purpose: To investigate the definition of planning target volumes (PTVs based on four-dimensional computed tomography (4DCT compared with conventional PTV definition and PTV definition using asymmetrical margins for thoracic primary esophageal cancer. Materials and methods: Forty-three patients with esophageal cancer underwent 3DCT and 4DCT simulation scans during free breathing. The motions of primary tumors located in the proximal (group A, middle (group B, and distal (group C thoracic esophagus were obtained from the 4DCT scans. PTV3D was defined on 3DCT using the tumor motion measured based on 4DCT, PTV conventional (PTVconv was defined on 3DCT by adding a 1.0 cm margin to the clinical target volume, and PTV4D was defined as the union of the target volumes contoured on the ten phases of the 4DCT images. The centroid positions, volumetric differences, and dice similarity coefficients were evaluated for all PTVs. Results: The median centroid shifts between PTV3D and PTV4D and between PTVconv and PTV4D in all three dimensions were <0.3 cm for the three groups. The median size ratios of PTV4D to PTV3D were 0.80, 0.88, and 0.71, and PTV4D to PTVconv were 0.67, 0.73, and 0.76 (χ2=–3.18, –2.98, and –3.06; P=0.001, 0.003, and 0.002 for groups A, B, and C, respectively. The dice similarity coefficients were 0.87, 0.90, and 0.81 between PTV4D and PTV3D and 0.80, 0.84, and 0.83 between PTV4D and PTVconv (χ2=–3.18, –2.98, and –3.06; P=0.001, 0.003, and 0.002 for groups A, B, and C, respectively. The difference between the degree of inclusion of PTV4D in PTV3D and that of PTV4D in PTVconv was <2% for all groups. Compared with PTVconv, the amount of irradiated normal tissue

  9. Three-dimensional versus four-dimensional dose calculation for volumetric modulated arc therapy of hypofractionated treatments

    Energy Technology Data Exchange (ETDEWEB)

    Ehrbar, Stefanie; Lang, Stephanie; Stieb, Sonja; Riesterer, Oliver; Stark, Luisa Sabrina; Guckenberger, Matthias; Kloeck, Stephan [University Hospital Zuerich (Switzerland). Dept. of Radiation Oncology

    2016-05-01

    Purpose: Respiratory motion is a non-negligible source of uncertainty in radiotherapy. A common approach is to delineate the target volume in all respiratory phases (ITV) and to calculate a treatment plan using the average reconstruction of the four-dimensional computed tomography (4DCT) scans. In this study the extent of the interplay effect caused by interaction between dynamic dose delivery and respiratory tumor motion, as well as other motion effects were investigated. These effects are often ignored when the ITV concept is used. Methods and Materials: Nine previously treated patients with in ten abdominal or thoracic cancer lesions (3 liver, 3 adrenal glands and 4 lung lesions) were selected for this planning study. For all patients, phase-sorted respiration-correlated 4DCT scans were taken, and volumetric modulated arc therapy (VMAT) treatments were planned using the ITV concept. Margins from ITV to planning target volume (PTV) of 3-10 mm were used. Plans were optimized and dose distributions were calculated on the average reconstruction of the 4DCT. 4D dose distributions were calculated to evaluate motion effects, caused by the interference of dynamic treatment delivery with respiratory tumor motion and inhomogeneously planned target dose. These calculations were performed on the phase-sorted CT series with a respiration-correlated assignment of the treatment plan's monitor units (MU) to the respiration phases of the 4DCT. The 4D dose was accumulated with rigid as well as deformable registrations of the CT series and compared to the original 3D dose distribution. Maximum, minimum and mean doses to ITV and PTV, and maximum or mean doses to organs at risk (OAR), were compared after rigid accumulation. The dose variation in the gross tumor volume (GTV) was compared after deformable registration. Results: Using rigid registrations, variations in the investigated dose parameters between 3D and 4D dose calculations were found to be within -2.1% to 1.4% for

  10. 2010 Canadian Cardiovascular Society/Canadian Society of Echocardiography Guidelines for Training and Maintenance of Competency in Adult Echocardiography.

    Science.gov (United States)

    Burwash, Ian G; Basmadjian, Arsene; Bewick, David; Choy, Jonathan B; Cujec, Bibiana; Jassal, Davinder S; MacKenzie, Scott; Nair, Parvathy; Rudski, Lawrence G; Yu, Eric; Tam, James W

    2011-01-01

    Guidelines for the provision of echocardiography in Canada were jointly developed and published by the Canadian Cardiovascular Society and the Canadian Society of Echocardiography in 2005. Since their publication, recognition of the importance of echocardiography to patient care has increased, along with the use of focused, point-of-care echocardiography by physicians of diverse clinical backgrounds and variable training. New guidelines for physician training and maintenance of competence in adult echocardiography were required to ensure that physicians providing either focused, point-of-care echocardiography or comprehensive echocardiography are appropriately trained and proficient in their use of echocardiography. In addition, revision of the guidelines was required to address technological advances and the desire to standardize echocardiography training across the country to facilitate the national recognition of a physician's expertise in echocardiography. This paper summarizes the new Guidelines for Physician Training and Maintenance of Competency in Adult Echocardiography, which are considerably more comprehensive than earlier guidelines and address many important issues not previously covered. These guidelines provide a blueprint for physician training despite different clinical backgrounds and help standardize physician training and training programs across the country. Adherence to the guidelines will ensure that physicians providing echocardiography have acquired sufficient expertise required for their specific practice. The document will also provide a framework for other national societies to standardize their training programs in echocardiography and will provide a benchmark by which competency in adult echocardiography may be measured.

  11. Three-dimensional Echocardiography in Valvular Heart Disease.

    Science.gov (United States)

    Kurklinsky, Andrew; Mankad, Sunil

    2012-01-01

    Recent technologic advances in 3-dimensional (3D) echocardiography, using parallel processing to scan a pyramidal volume, have allowed for a superior ability to describe valvular anatomy using both transthoracic and transesophageal echocardiography. Although still in evolution and at an early phase of adaptation with respect to its clinical application, 3D echocardiography has emerged as an important clinical tool in the assessment of valvular heart disease. Three-dimensional echocardiography provides unique perspectives of valvular structures by presenting "en face" views of valvular structures, allowing for a better understanding of the topographical aspects of pathology, and a refined definition of the spatial relationships of intracardiac structures. Three-dimensional echocardiography makes available indices not described by 2D echocardiography and has been demonstrated to be superior to 2D echocardiography in a variety of valvular disease scenarios. The information gained from 3D echocardiography has especially made an impact in guiding clinical decisions in the evaluation of mitral valve (MV) disease. The decision of early surgery in degenerative MV disease is based on the suitability of repair, and the suitability of repair is generally based on echocardiography. The superior understanding of MV anatomy afforded by 3D echocardiography has been shown to be quite valuable in this setting. This review will describe the contemporary use of 3D echocardiography in the assessment of valvular heart disease, including MV, aortic, tricuspid, and prosthetic valve abnormalities. This article illustrates how 3D echocardiography can complement current echocardiography techniques in the management of valvular heart disease.

  12. Advanced techniques in echocardiography in small animals.

    Science.gov (United States)

    Chetboul, Valérie

    2010-07-01

    Transthoracic echocardiography has become a major imaging tool for the diagnosis and management of canine and feline cardiovascular diseases. During the last decade, more recent advances in ultrasound technology with the introduction of newer imaging modalities, such as tissue Doppler imaging, strain and strain rate imaging, and 2-dimensional speckle tracking echocardiography, have provided new parameters to assess myocardial performance, including regional myocardial velocities and deformation, ventricular twist, and mechanical synchrony. An outline of these 4 recent ultrasound techniques, their impact on the understanding of right and left ventricular function in small animals, and their application in research and clinical settings are given in this article.

  13. Three-dimensional echocardiography in valve disease.

    Science.gov (United States)

    Colombo, Chiara; Tamborini, Gloria; Pepi, Mauro; Alimento, Marina; Fiorentini, Cesare

    2007-01-01

    This review covers the role of three-dimensional (3D) echocardiography in the diagnosis of heart valve disease. Several factors have contributed to the evolution of this technique, which is currently a simple and routine method: rapid evolution in probe and computer technologies, demonstration that 3D data sets allowed more complete and accurate evaluation of cardiac structures, emerging clinical experience indicating the strong potential particularly in valve diseases, volume and function of the two ventricle measurements and several other fields. This report will review current and future applications of 3D echocardiography in mitral, aortic and tricuspid valve diseases underlying both qualitative (morphologic) and quantitative advantages of this technique.

  14. Simulation for transthoracic echocardiography of aortic valve

    Science.gov (United States)

    Nanda, Navin C.; Kapur, K. K.; Kapoor, Poonam Malhotra

    2016-01-01

    Simulation allows interactive transthoracic echocardiography (TTE) learning using a virtual three-dimensional model of the heart and may aid in the acquisition of the cognitive and technical skills needed to perform TTE. The ability to link probe manipulation, cardiac anatomy, and echocardiographic images using a simulator has been shown to be an effective model for training anesthesiology residents in transesophageal echocardiography. A proposed alternative to real-time reality patient-based learning is simulation-based training that allows anesthesiologists to learn complex concepts and procedures, especially for specific structures such as aortic valve. PMID:27397455

  15. Automated analysis of 3D echocardiography

    NARCIS (Netherlands)

    Stralen, Marijn van

    2009-01-01

    In this thesis we aim at automating the analysis of 3D echocardiography, mainly targeting the functional analysis of the left ventricle. Manual analysis of these data is cumbersome, time-consuming and is associated with inter-observer and inter-institutional variability. Methods for reconstruction o

  16. Dynamic 3D echocardiography in virtual reality.

    NARCIS (Netherlands)

    A.E. van den Bosch (Annemien); A.H.J. Koning (Anton); F.J. Meijboom (Folkert); J.S. McGhie (Jackie); M.L. Simoons (Maarten); P.J. van der Spek (Peter); A.J.J.C. Bogers (Ad)

    2005-01-01

    textabstractBACKGROUND: This pilot study was performed to evaluate whether virtual reality is applicable for three-dimensional echocardiography and if three-dimensional echocardiographic 'holograms' have the potential to become a clinically useful tool. METHODS: Three-dimensional echocardiographic d

  17. Transesophageal echocardiography assessment of severe ostial left main coronary stenosis

    Science.gov (United States)

    Firstenberg, M. S.; Greenberg, N. L.; Lin, S. S.; Garcia, M. J.; Alexander, L. A.; Thomas, J. D.

    2000-01-01

    Doppler echocardiography is commonly used in the assessment of stenotic valvular orifices. We describe the application of transesophageal echocardiography for the detection of a critical ostial left main coronary stenosis. Because preoperative coronary angiography often is not routinely performed in young patients undergoing valve surgery, application of Doppler echocardiography can potentially prevent catastrophic complications, particularly in atypical cases.

  18. Recent advances in echocardiography for valvular heart disease.

    Science.gov (United States)

    Hahn, Rebecca

    2015-01-01

    Echocardiography is the imaging modality of choice for the assessment of patients with valvular heart disease. Echocardiographic advancements may have particular impact on the assessment and management of patients with valvular heart disease. This review will summarize the current literature on advancements, such as three-dimensional echocardiography, strain imaging, intracardiac echocardiography, and fusion imaging, in this patient population.

  19. Dobutamine stress echocardiography: a review and update

    Directory of Open Access Journals (Sweden)

    Gilstrap LG

    2014-04-01

    Full Text Available Lauren Gray Gilstrap,1 R Sacha Bhatia,2 Rory B Weiner,3 David M Dudzinski3 1Division of Cardiology, Brigham and Women's Hospital, Boston, MA, USA; 2Institute for Health Systems Solutions, Women's College Hospital, Toronto, ON, Canada; 3Cardiology Division, Massachusetts General Hospital, Boston, MA, USA Abstract: Stress echocardiography is a noninvasive cardiovascular diagnostic test that provides functional and hemodynamic information in the assessment of a number of cardiac diseases. Performing stress echocardiography with a pharmacologic agent such as dobutamine allows for simulation of increased heart rate and increased myocardial physiologic demands in patients who may be unable to exercise due to musculoskeletal or pulmonary comorbidities. Dobutamine stress echocardiography (DSE, like exercise echocardiography, has found its primary application in ischemic heart disease, with roles in identification of obstructive epicardial coronary artery disease, detection of viable myocardium, and assessment of the efficacy of anti-ischemic medical therapy in patients with known coronary artery disease. DSE features prominently in the evaluation and management of valvular heart disease by helping to assess the effects of mitral and aortic stenoses, as well as a specific use in differentiating true severe valvular aortic stenosis from pseudostenosis that may occur in the setting of left ventricular systolic dysfunction. DSE is generally well tolerated, and its side effects and contraindications generally relate to consequences of excess inotropic and/or chronotropic stimulation of the heart. The aim of this paper is to review the indications, contraindications, advantages, disadvantages, and risks of DSE. Keywords: stress echocardiography, dobutamine, coronary artery disease, myocardial ischemia

  20. Speckle Tracking Imaging in Normal Stress Echocardiography.

    Science.gov (United States)

    Leitman, Marina; Tyomkin, Vladimir; Peleg, Eli; Zyssman, Izhak; Rosenblatt, Simcha; Sucher, Edgar; Gercenshtein, Vered; Vered, Zvi

    2017-04-01

    Exercise stress echocardiography is a widely used modality for the diagnosis and follow-up of patients with coronary artery disease. During the last decade, speckle tracking imaging has been used increasingly for accurate evaluation of cardiac function. This work aimed to assess speckle-tracking imaging parameters during nonischemic exercise stress echocardiography. During 2011 to 2014 we studied 46 patients without history of coronary artery disease, who completed exercise stress echocardiography protocol, had normal left ventricular function, a nonischemic response, and satisfactory image quality. These exams were analyzed with speckle-tracking imaging software at rest and at peak exercise. Peak strain and time-to-peak strain were measured at rest and after exercise. Clinical follow-up included a telephone contact 1 to 3 years after stress echo exam, confirming freedom from coronary events during this time. Global and regional peak strain increased following exercise. Time-to-peak global and regional strain and time-to-peak strain adjusted to the heart rate were significantly shorter in all segments after exercise. Rest-to-stress ratio of time-to-peak strain adjusted to the heart rate was 2.0 to 2.8. Global and regional peak strain rise during normal exercise echocardiography. Peak global and regional strain occur before or shortly after aortic valve closure at rest and after exercise, and the delay is more apparent at the basal segments. Time-to-peak strain normally shortens significantly during exercise; after adjustment to heart rate it shortens by a ratio of 2.0 to 2.8. These data may be useful for interpretation of future exercise stress speckle-tracking echocardiography studies. © 2016 by the American Institute of Ultrasound in Medicine.

  1. The relationship between four-dimensional θ = π Yang-Mills theory and the two-dimensional Wess-Zumino-Novikov-Witten model

    Institute of Scientific and Technical Information of China (English)

    寇谡鹏

    2002-01-01

    Used the dimensional reduction in the sense of Parisi and Sourlas, the gauge fixing term of the four-dimensionalYang-Mills field without the theta term is reduced to a two-dimensional principal chiral model. By adding the θ term(θ = π), the two-dimensional principal chiral model changes into the two-dimensional level 1 Wess-Zumino-Novikov-Witten model. The non-trivial fixed point indicates that Yang-Mills theory at θ = π is a critical theory without massgap and confinement.

  2. Application of a Four-dimensional Mathematical Model in the Establishment of an Early Post-burn Cerebral Oedema Model in Severely Burned Dogs

    OpenAIRE

    Haitao, L.; Dajun, Y.; Kaifa, W.; Xiuwu, B.; Jiansen, S.; Zongchen, Y.

    2005-01-01

    The aim of this study was to explore the spatiotemporal development of cerebral oedema in the early stage of severe burn (50% TBSA, third degree), using a four-dimensional (4D) mathematical model. Twenty-six male mongrel dogs were randomly divided into control and 6, 12, 18, and 24 post-burn hour (PBH) groups. The manifestation of magnetic resonance imaging (MRI) and histopathology, changes of brain water content, and intracranial pressure were observed in each group respectively. A 4D mathem...

  3. Artifacts in three-dimensional transesophageal echocardiography.

    Science.gov (United States)

    Faletra, Francesco Fulvio; Ramamurthi, Alamelu; Dequarti, Maria Cristina; Leo, Laura Anna; Moccetti, Tiziano; Pandian, Natesa

    2014-05-01

    Three-dimensional (3D) transesophageal echocardiography (TEE) is subject to the same types of artifacts encountered on two-dimensional TEE. However, when displayed in a 3D format, some of the artifacts appear more "realistic," whereas others are unique to image acquisition and postprocessing. Three-dimensional TEE is increasingly used in the setting of percutaneous catheter-based interventions and ablation procedures, and 3D artifacts caused by the metallic components of catheters and devices are particularly frequent. Knowledge of these artifacts is of paramount relevance to avoid misinterpretation of 3D images. Although artifacts and pitfalls on two-dimensional echocardiography are well described and classified, a systematic description of artifacts in 3D transesophageal echocardiographic images and how they affect 3D imaging is still absent. The aim of this review is to describe the most relevant artifacts on 3D TEE, with particular emphasis on those occurring during percutaneous interventions for structural heart disease and ablation procedures.

  4. Exercise echocardiography for structural heart disease.

    Science.gov (United States)

    Izumo, Masaki; Akashi, Yoshihiro J

    2016-03-01

    Since the introduction of transcatheter structural heart intervention, the term "structural heart disease" has been widely used in the field of cardiology. Structural heart disease refers to congenital heart disease, valvular heart disease, and cardiomyopathy. In structural heart disease, valvular heart disease is frequently identified in the elderly. Of note, the number of patients who suffer from aortic stenosis (AS) and mitral regurgitation (MR) is increasing in developed countries because of the aging of the populations. Transcatheter aortic valve replacement and percutaneous mitral valve repair has been widely used for AS and MR, individually. Echocardiography is the gold standard modality for initial diagnosis and subsequent evaluation of AS and MR, although the difficulties in assessing patients with these diseases still remain. Here, we review the clinical usefulness and prognostic impact of exercise echocardiography on structural heart disease, particularly on AS and MR.

  5. Application of Contrast Echocardiography in Invasive Cardiology

    Directory of Open Access Journals (Sweden)

    Mustafa Bulut

    2010-12-01

    Full Text Available Contrast echocardiography by rendering better imaging of the borders of cardiac chambers is a useful tool for evaluating cardiac function, mass, myocardial vascularization, microvascular structure (small vessel vasculature and viability. Contrast was first started to be used for patients with suboptimal image quality. It can be used in detecting defects in myocardial blood supply in patients with chest pain and determining the success of interventionalprocedures. It can also be of help in demonstrating myocardial viability after reperfusion treatment in patients who had myocardial infarction. It is expected to be used more widely in invasive cardiology for decision making, guiding and determining the success of the procedures. Advances in imaging techniques , development of contrast materials for evaluation of left system, contrast echocardiography may become a routine clinical practice.

  6. Simulation-based training in echocardiography.

    Science.gov (United States)

    Biswas, Monodeep; Patel, Rajendrakumar; German, Charles; Kharod, Anant; Mohamed, Ahmed; Dod, Harvinder S; Kapoor, Poonam Malhotra; Nanda, Navin C

    2016-10-01

    The knowledge gained from echocardiography is paramount for the clinician in diagnosing, interpreting, and treating various forms of disease. While cardiologists traditionally have undergone training in this imaging modality during their fellowship, many other specialties are beginning to show interest as well, including intensive care, anesthesia, and primary care trainees, in both transesophageal and transthoracic echocardiography. Advances in technology have led to the development of simulation programs accessible to trainees to help gain proficiency in the nuances of obtaining quality images, in a low stress, pressure free environment, often with a functioning ultrasound probe and mannequin that can mimic many of the pathologies seen in living patients. Although there are various training simulation programs each with their own benefits and drawbacks, it is clear that these programs are a powerful tool in educating the trainee and likely will lead to improved patient outcomes. © 2016, Wiley Periodicals, Inc.

  7. Echocardiography diagnosis of myocardial infarction complications

    Directory of Open Access Journals (Sweden)

    N.D. Oryshchyn

    2016-03-01

    Full Text Available Diagnosis and management of myocardial infarction complications are discussed in this article. These complications are associated with high level of mortality and surgery is a main treatment method. High level of suspicion and early diagnosis are essential for appropriate treatment and improvement of prognosis. Echocardiography is a main diagnostic method. Analysis of literature about contemporary management of mechanical complications of myocardial infarction has been performed, case reports are presented.

  8. Application of Contrast Echocardiography in Invasive Cardiology

    OpenAIRE

    2010-01-01

    Contrast echocardiography by rendering better imaging of the borders of cardiac chambers is a useful tool for evaluating cardiac function, mass, myocardial vascularization, microvascular structure (small vessel vasculature) and viability. Contrast was first started to be used for patients with suboptimal image quality. It can be used in detecting defects in myocardial blood supply in patients with chest pain and determining the success of interventionalprocedures. It can also be of help in de...

  9. Dobutamine stress echocardiography: a review and update

    OpenAIRE

    Gilstrap LG; Bhatia RS; Weiner RB; Dudzinski DM

    2014-01-01

    Lauren Gray Gilstrap,1 R Sacha Bhatia,2 Rory B Weiner,3 David M Dudzinski3 1Division of Cardiology, Brigham and Women's Hospital, Boston, MA, USA; 2Institute for Health Systems Solutions, Women's College Hospital, Toronto, ON, Canada; 3Cardiology Division, Massachusetts General Hospital, Boston, MA, USA Abstract: Stress echocardiography is a noninvasive cardiovascular diagnostic test that provides functional and hemodynamic information in the assessment of a number of cardiac...

  10. Vocal cord dysfunction diagnosed by four-dimensional dynamic volume computed tomography in patients with difficult-to-treat asthma: A case series.

    Science.gov (United States)

    Cheng, Wei-Tso; Chen, Huan-Wen; Su, I-Hao; Fang, Ji-Tseng; Kuo, Han-Pin; Huang, Chien-Da

    2015-12-01

    Patients with asthma may also have vocal cord dysfunction (VCD), which leads to poor control of the asthma. Once patients are diagnosed with difficult-to-treat asthma with poor control, VCD should be excluded or treated accordingly. The gold standard for diagnosis of VCD is to perform a laryngoscopy. However, this procedure is invasive and may not be suitable for patients with difficult-to-treat asthma. Four-dimensional (4D) dynamic volume computed tomography (CT) is a noninvasive method for quantification of laryngeal movement, and can serve as an alternative for the diagnosis of VCD. Herein, we present a series of five cases with difficult-to-treat asthma patients who were diagnosed with VCD by 4D dynamic volume CT. Clinicians should be alert to the possibility of VCD when poor control is noted in patients with asthma. Early diagnosis by noninvasive 4D dynamic volume CT can decrease excessive doses of inhaled corticosteroids.

  11. Rotationally acquired four-dimensional optical coherence tomography of embryonic chick hearts using retrospective gating on the common central A-scan

    DEFF Research Database (Denmark)

    Happel, Christoph M.; Thommes, Jan; Thrane, Lars;

    2011-01-01

    We introduce a new method of rotational image acquisition for four-dimensional (4D) optical coherence tomography (OCT) of beating embryonic chick hearts. The rotational axis and the central A-scan of the OCT are identical. An out-of-phase image sequence covering multiple heartbeats is acquired...... at every angle of an incremental rotation of the deflection mirrors of the OCT system. Image acquisition is accomplished after a rotation of 180◦. Comparison of a displayed live M-mode of the central A-scan with a reference M-mode allows instant detection of translational movements of the embryo....... For calculation of 4D data sets, we apply an imagebased retrospective gating algorithm using the phase information of the common central A-scan present in all acquired images. This leads to cylindrical three-dimensional data sets for every time step of the cardiac cycle that can be used for 4D visualization...

  12. Development of Four Dimensional Human Model that Enables Deformation of Skin, Organs and Blood Vessel System During Body Movement - Visualizing Movements of the Musculoskeletal System.

    Science.gov (United States)

    Suzuki, Naoki; Hattori, Asaki; Hashizume, Makoto

    2016-01-01

    We constructed a four dimensional human model that is able to visualize the structure of a whole human body, including the inner structures, in real-time to allow us to analyze human dynamic changes in the temporal, spatial and quantitative domains. To verify whether our model was generating changes according to real human body dynamics, we measured a participant's skin expansion and compared it to that of the model conducted under the same body movement. We also made a contribution to the field of orthopedics, as we were able to devise a display method that enables the observer to more easily observe the changes made in the complex skeletal muscle system during body movements, which in the past were difficult to visualize.

  13. Four-dimensional (4D) flow of the whole heart and great vessels using real-time respiratory self-gating

    DEFF Research Database (Denmark)

    Uribe, Sergio; Beerbaum, Philipp; Sørensen, Thomas Sangild

    2009-01-01

    Four-dimensional (4D) flow imaging has been used to study flow patterns and pathophysiology, usually focused on specific thoracic vessels and cardiac chambers. Whole-heart 4D flow at high measurement accuracy covering the entire thoracic cardiovascular system would be desirable to simplify...... and improve hemodynamic assessment. This has been a challenge because compensation of respiratory motion is difficult to achieve, but it is paramount to limit artifacts and improve accuracy. In this work we propose a self-gating technique for respiratory motion-compensation integrated into a whole-heart 4D...... flow acquisition that overcomes these challenges. Flow components are measured in all three directions for each pixel over the complete cardiac cycle, and 1D volume projections are obtained at certain time intervals for respiratory gating in real time during the acquisition. The technique was tested...

  14. The use of echocardiography in acute cardiovascular care

    DEFF Research Database (Denmark)

    Lancellotti, Patrizio; Price, Susanna; Edvardsen, Thor

    2014-01-01

    of echocardiography in acute cardiovascular care. In this document, we describe the practical applications of echocardiography in patients with acute cardiac conditions, in particular with acute chest pain, acute heart failure, suspected cardiac tamponade, complications of myocardial infarction, acute valvular heart...... disease including endocarditis, acute disease of the ascending aorta and post-intervention complications. Specific issues regarding echocardiography in other acute cardiovascular care scenarios are also described....

  15. The use of echocardiography in acute cardiovascular care

    DEFF Research Database (Denmark)

    Lancellotti, Patrizio; Price, Susanna; Edvardsen, Thor

    2015-01-01

    of echocardiography in acute cardiovascular care. In this document, we describe the practical applications of echocardiography in patients with acute cardiac conditions, in particular with acute chest pain, acute heart failure, suspected cardiac tamponade, complications of myocardial infarction, acute valvular heart...... disease including endocarditis, acute disease of the ascending aorta and post-intervention complications. Specific issues regarding echocardiography in other acute cardiovascular care scenarios are also described....

  16. The use of echocardiography in acute cardiovascular care

    DEFF Research Database (Denmark)

    Lancellotti, Patrizio; Price, Susanna; Edvardsen, Thor

    2015-01-01

    of echocardiography in acute cardiovascular care. In this document, we describe the practical applications of echocardiography in patients with acute cardiac conditions, in particular with acute chest pain, acute heart failure, suspected cardiac tamponade, complications of myocardial infarction, acute valvular heart...... disease including endocarditis, acute disease of the ascending aorta and post-intervention complications. Specific issues regarding echocardiography in other acute cardiac care scenarios are also described....

  17. Echocardiography as a Research and Clinical Tool in Veterinary Medicine

    OpenAIRE

    Allen, D G

    1982-01-01

    Echocardiography is the accepted term for the study of cardiac ultrasound. Although a relatively new tool for the study of the heart in man it has already found wide acceptance in the area of cardiac research and in the study of clinical cardiac disease. Animals had often been used in the early experiments with cardiac ultrasound, but only recently has echocardiography been used as a research and clinical tool in veterinary medicine. In this report echocardiography is used in the research of ...

  18. Establishment of Rural Sports Combined System of "Four-Dimensional Health"%农村体育"四维健康"组合体系的构建

    Institute of Scientific and Technical Information of China (English)

    伊向仁; 李强

    2009-01-01

    根据农村传统习惯和场地特征,结合农民的生活规律、劳动特点,构建具有农村特色、切实可行的农村体育"四维健康"组合体系.包括农村体育身体健康服务体系;农村体育心理健康服务体系;农村体育社会健康服务体系;农村体育环境健康服务体系.通过政府组织、经济杠杆、体育文化、职业教育、法律法规意识引导等,建立农村体育"四维健康"长期引导机制.%Based on rural traditional habits and playground features and combined with peasants' life law and working characteristics, it established a distinctive-rural-feature-having and feasible rural sports combined system of "Four-dimensional Health", which included the service system of rural sport and physical health, the service system of peasants' sport and mental health, the service system of rural sport and social health as well as the service system of rural sport and environment health, and meanwhile proposed to set up a long-term guiding mechanism of "Four-dimensional Health" of rural sport through the guidances from government departments, economic lever, science and technology, sports culture, vocational education, consciousness of law and statutes and so forth.

  19. Recent advances in echocardiography for nuclear medicine physician

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Geu Ru; Shin, Dong Gu [Yeungnam University College of Medicine, Daegu (Korea, Republic of)

    2005-10-15

    Echocardiography is one of the most frequently used techniques for diagnosing cardiovascular diseases. Over the last twenty years, technological advances have enabled the application of high-quality imaging. Important recent developments have occurred in echocardiography that are already being used clinically. Equipment and hardware is now available to produce real time three-dimensional and contrast enhanced imaging. Tissue Doppler and stress echocardiography have provided potential benefit to analyze hemodynamic information of heart. This review discusses each of these new developments and their potential impact on the practice of echocardiography and cardiology in general.

  20. Echocardiography is dispensable in uncomplicated Staphylococcus aureus bacteremia

    National Research Council Canada - National Science Library

    Khatib, Riad; Sharma, Mamta

    2013-01-01

    Current Staphylococcus aureus bacteremia (SAB) practice guidelines stratify treatment duration according to the likelihood of complications and recommend transesophageal echocardiography (TEE) in all cases...

  1. Predicting and measuring fluid responsiveness with echocardiography

    Directory of Open Access Journals (Sweden)

    Ashley Miller

    2016-06-01

    Full Text Available Echocardiography is ideally suited to guide fluid resuscitation in critically ill patients. It can be used to assess fluid responsiveness by looking at the left ventricle, aortic outflow, inferior vena cava and right ventricle. Static measurements and dynamic variables based on heart–lung interactions all combine to predict and measure fluid responsiveness and assess response to intravenous fluid esuscitation. Thorough knowledge of these variables, the physiology behind them and the pitfalls in their use allows the echocardiographer to confidently assess these patients and in combination with clinical judgement manage them appropriately.

  2. Therapeutic implications of transesophageal echocardiography after transthoracic echocardiography on acute stroke patients

    Directory of Open Access Journals (Sweden)

    Tiago Tribolet de Abreu

    2008-02-01

    Full Text Available Tiago Tribolet de Abreu, Sonia Mateus, Cecilia Carreteiro, Jose CorreiaLaboratorio de Ultrasonografia Cardiaca e Neurovascular, Hospital do Espirito Santo-Evora, E. P. E., PortugalBackground: The role of transesophageal echocardiography (TEE in the evaluation of acute stroke patients is still ill-defined. We conducted a prospective observational study to find the prevalence of TEE findings that indicate anticoagulation as beneficial, in acute ischemic stroke patients without indication for anticoagulation based on clinical, electrocardiographic and transthoracic echocardiography (TTE findings.Methods: We prospectively studied all patients referred to our laboratory for TTE and TEE. Patients were excluded if the diagnosis was not acute ischemic stroke or if they had an indication for anticoagulation based on clinical, electrocardiographic, or TTE data. Patients with TEE findings that might indicate anticoagulation as beneficial were identified.Results: A total of 84 patients with acute ischemic stroke and without indication for anticoagulation based on clinical and electrocardiographic or TTE data were included in the study. Findings indicating anticoagulation as beneficial were found in 32.1%: spontaneous echo contrast (1.2%, complex aortic atheroma (27.4%, thrombus (8.3%, and simultaneous patent foramen ovale and atrial septal aneurysm (2.4%.Conclusions: The results of our study show that TEE can have therapy implications in 32.1% of ischemic stroke patients in sinus rhythm and with TTE with no indication for anticoagulation.Keywords: acute ischemic stroke, transesophageal echocardiography, transthoracic echocardiography, therapy

  3. Four-dimensional electron microscopy.

    Science.gov (United States)

    Zewail, Ahmed H

    2010-04-09

    The discovery of the electron over a century ago and the realization of its dual character have given birth to one of the two most powerful imaging instruments: the electron microscope. The electron microscope's ability to resolve three-dimensional (3D) structures on the atomic scale is continuing to affect different fields, including materials science and biology. In this Review, we highlight recent developments and inventions made by introducing the fourth dimension of time in electron microscopy. Today, ultrafast electron microscopy (4D UEM) enables a resolution that is 10 orders of magnitude better than that of conventional microscopes, which are limited by the video-camera rate of recording. After presenting the central concept involved, that of single-electron stroboscopic imaging, we discuss prototypical applications, which include the visualization of complex structures when unfolding on different length and time scales. The developed UEM variant techniques are several, and here we illucidate convergent-beam and near-field imaging, as well as tomography and scanning-pulse microscopy. We conclude with current explorations in imaging of nanomaterials and biostructures and an outlook on possible future directions in space-time, 4D electron microscopy.

  4. Four dimensional trace space measurement

    CERN Document Server

    Hernández, M E; Winick, Herman; Smith, T

    2003-01-01

    Future high energy colliders and FELs (Free Electron Lasers) such as the proposed LCLS (Linac Coherent Light Source) at SLAC require high brightness electron beams. In general a high brightness electron beam will contain a large number of electrons that occupy a short longitudinal duration, can be focused to a small transverse area while having small transverse divergences. Therefore the beam must have a high peak current and occupy small areas in transverse phase space and so have small transverse emittances. Additionally the beam should propagate at high energy and have a low energy spread to reduce chromatic effects. The requirements of the LCLS for example are pulses which contain 1010 electrons in a temporal duration of 10 ps FWHM with projected normalized transverse emittances of 1π mm mrad. Currently the most promising method of producing such a beam is the RF photoinjector. The GTF (Gun Test Facility) at SLAC was constructed to produce and characterize laser and electron beams which fulfill the...

  5. Four-Dimensional Golden Search

    Energy Technology Data Exchange (ETDEWEB)

    Fenimore, Edward E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-02-25

    The Golden search technique is a method to search a multiple-dimension space to find the minimum. It basically subdivides the possible ranges of parameters until it brackets, to within an arbitrarily small distance, the minimum. It has the advantages that (1) the function to be minimized can be non-linear, (2) it does not require derivatives of the function, (3) the convergence criterion does not depend on the magnitude of the function. Thus, if the function is a goodness of fit parameter such as chi-square, the convergence does not depend on the noise being correctly estimated or the function correctly following the chi-square statistic. And, (4) the convergence criterion does not depend on the shape of the function. Thus, long shallow surfaces can be searched without the problem of premature convergence. As with many methods, the Golden search technique can be confused by surfaces with multiple minima.

  6. Transesophageal echocardiography: Instrumentation and system controls

    Directory of Open Access Journals (Sweden)

    Mahesh Prabhu

    2012-01-01

    Full Text Available Transesophageal echocardiography (TEE is a semi-invasive, monitoring and diagnostic tool, which is used in the perioperative management of cardiac surgical and hemodynamically unstable patients. The low degree of invasiveness and the capacity to visualize and assimilate dynamic information that can change the course of the patient management is an important advantage of TEE. Although TEE is reliable, comprehensive, credible, and cost-effective, it must be performed by a trained echocardiographer who understands the indications and the potential complications of the procedure, and has the ability to achieve proper acquisition and interpretation of the echocardiographic data. Adequate knowledge of the physics of ultrasound and the TEE machine controls is imperative to optimize image quality, reduce artifacts, and prevent misinterpretation of diagnosis. Two-dimensional (2D and Motion (M mode imaging are used for obtaining anatomical information, while Doppler and Color Flow imaging are used for information on blood flow. 3D technology enables us to view the cardiac structures from different perspectives. Despite the recent advances of 3D TEE, a sharp, optimized 2D image is pivotal for the reconstruction. This article describes the relevant underlying physical principles of ultrasound and focuses on a systematic approach to instrumentation and use of controls in the practical use of transesophageal echocardiography.

  7. A novel platform device for rodent echocardiography.

    Science.gov (United States)

    Kutschka, Ingo; Sheikh, Ahmad Y; Sista, Ramachandra; Hendry, Stephen L; Chun, Hyung J; Hoyt, Grant; Kutschka, Werner; Pelletier, Marc P; Quertermous, Tom; Wu, Joseph C; Robbins, Robert C

    2007-06-06

    Acquisition of echocardiographic data from rodents is subject to wide variability due to variations in technique. We hypothesize that a dedicated imaging platform can aid in standardization of technique and improve the quality of images obtained. We constructed a device consisting of a boom-mounted steel platform frame (25 x 35 x 3 cm) on which a transparent polyethylene membrane is mounted. The animal is placed onto the membrane and receives continual inhaled anesthesia via an integrated port. The membrane allows for probe positioning from beneath the animal to obtain standard echo-views in left lateral decubitus or prone positions. The frame can be set at any desired angle ranging from 0 to 360 degrees along either the long or short axis. Adult male Sprague-Dawley rats (n = 5) underwent echocardiography (General Electric, Vivid 7, 14 MHz) using the platform. The device allowed for optimal positioning of animals for a variety of standard echocardiographic measurements. Evaluations among all animals showed minimal variability between two different operators and time points. We tested the feasibility of the device for supporting the assessment of cardiac function in a disease model by evaluating a separate cohort of adult male spontaneously hypertensive rats (n = 5) that underwent left anterior descending coronary artery ligation. Serial echocardiography demonstrated statistically significant decreases of fractional shortening and ejection fraction (p rats. Future studies will focus on improving this technology to allow for standardized high-throughput echocardiographic analysis in small animal models of disease.

  8. Generalized tetany: an unusual complication during dobutamine stress echocardiography.

    Science.gov (United States)

    Abbas, Amr E; Loftis, Rochelle; Lester, Steven J; Crawford, Michael B; Appleton, Christopher P

    2002-11-01

    Dobutamine stress echocardiography is a frequently used noninvasive method for the evaluation of inducible myocardial ischemia, myocardial viability, and preoperative cardiac risk. Although its clinical safety has been validated, side effects and complications especially with the coadministration of atropine can occur. We report a case of generalized tetany in a 49-year-old woman undergoing dobutamine stress echocardiography.

  9. Advanced quantitative echocardiography in arrhythmogenic right ventricular cardiomyopathy

    DEFF Research Database (Denmark)

    Kjaergaard, Jesper; Hastrup Svendsen, Jesper; Sogaard, Peter

    2007-01-01

    of global and regional function, but the diagnostic potential remains to be assessed. METHODS: Twenty patients with previously established ARVC were evaluated by 3-dimensional echocardiography and DTI, and compared with 32 age- and sex-matched control subjects. RESULTS: Using 3-dimensional echocardiography...

  10. Color M-mode and pulsed wave tissue Doppler echocardiography

    DEFF Research Database (Denmark)

    Møller, J E; Søndergaard, E; Poulsen, S H;

    2001-01-01

    To assess the association between color M-mode flow propagation velocity and the early diastolic mitral annular velocity (E(m)) obtained with tissue Doppler echocardiography and to assess the prognostic implications of the indexes, echocardiography was performed on days 1 and 5, and 1 and 3 months...

  11. Automated analysis of three-dimensional stress echocardiography

    NARCIS (Netherlands)

    K.Y.E. Leung (Esther); M. van Stralen (Marijn); M.G. Danilouchkine (Mikhail); G. van Burken (Gerard); M.L. Geleijnse (Marcel); J.H.C. Reiber (Johan); N. de Jong (Nico); A.F.W. van der Steen (Ton); J.G. Bosch (Johan)

    2011-01-01

    textabstractReal-time three-dimensional (3D) ultrasound imaging has been proposed as an alternative for two-dimensional stress echocardiography for assessing myocardial dysfunction and underlying coronary artery disease. Analysis of 3D stress echocardiography is no simple task and requires considera

  12. Advances in the Evaluation of Cardiovascular Function by Echocardiography

    NARCIS (Netherlands)

    A. Nemes (Attila)

    2007-01-01

    textabstractThe aim of this thesis was to study the advances in the evaluation of cardiovascular function by 2D and real-time 3D stress echocardiography and vascular stiffness measurements. Stress echocardiography is a widely used non-invasive stress modality for the detection of coronary artery dis

  13. MODERN POSSIBILITIES OF SPECKLE TRACKING ECHOCARDIOGRAPHY IN CLINICAL PRACTICE

    Directory of Open Access Journals (Sweden)

    V. S. Nikiforov

    2017-01-01

    Full Text Available Speckle-tracking echocardiography is promising modern technique for evaluation of structural and functional changes in the myocardium. It evaluates the indicator of global longitudinal myocardial deformation, which is more sensitive than ejection fraction to early changes of left ventricular contractility. The diagnostic capabilities of speckle tracking echocardiography are reflected in clinical recommendations and consensus statements of European Society of Cardiology (ESC, European Association of Cardiovascular Imaging (EACVI and American Society of Echocardiography (ASE. The aim of this paper is describe basic principles of speckle tracking echocardiography and clinical applications of this new technology. Attention is paid to the use of speckle tracking echocardiography in such heart pathologies as heart failure, coronary heart disease and myocardial infarction, left ventricular hypertrophy in arterial hypertension, hypertrophic cardiomyopathy and amyloidosis of the heart, valvular heart disease, constrictive pericarditis and cancer therapy-induced cardiotoxicity.

  14. Application of Echocardiography on Transgenic Mice with Cardiomyopathies

    Directory of Open Access Journals (Sweden)

    G. Chen

    2012-01-01

    Full Text Available Cardiomyopathies are common cardiac disorders that primarily affect cardiac muscle resulting in cardiac dysfunction and heart failure. Transgenic mouse disease models have been developed to investigate the cellular mechanisms underlying heart failure and sudden cardiac death observed in cardiomyopathy cases and to explore the therapeutic outcomes in experimental animals in vivo. Echocardiography is an essential diagnostic tool for accurate and noninvasive assessment of cardiac structure and function in experimental animals. Our laboratory has been among the first to apply high-frequency research echocardiography on transgenic mice with cardiomyopathies. In this work, we have summarized our and other studies on assessment of systolic and diastolic dysfunction using conventional echocardiography, pulsed Doppler, and tissue Doppler imaging in transgenic mice with various cardiomyopathies. Estimation of embryonic mouse hearts has been performed as well using this high-resolution echocardiography. Some technical considerations in mouse echocardiography have also been discussed.

  15. The Value of Down Syndrome Screening Combined with Four Dimensional Colour Doppler Ultrasound in Prenatal Diagnosis%唐氏筛查联合四维彩超在产前诊断中的价值

    Institute of Scientific and Technical Information of China (English)

    邓玲; 汤辉; 黎兴盛; 郭平

    2015-01-01

    Objective:To explore the application value of Down syndrome screening combined with four dimensional colour doppler ultrasound in prenatal diagnosis.Method:From January 2011 to December 2014, 2578 cases of pregnant women for 14 to 24 weeks were selected in maternity clinics in our hospital,they were examined by Down syndrome screening and four dimensional colour doppler ultrasound.Result:2578 cases of pregnant women were all examined by Down syndrome screening and four dimensional colour doppler ultrasound. Positive rate of Down syndrome screening was 4.84%,positive rate of was four dimensional colour doppler ultrasound was 0.96%,positive rate of combined examination was 5.81%, positive rate between Down syndrome screening and combined examination had no statistical significance (P>0.05),positive rate between four dimensional colour doppler ultrasound and combined examination had statistical significance(P0.05),与四维彩超筛查比较差异有统计学意义(P<0.05).结论:唐氏筛查联合四维彩超在产前筛查中的意义重大,可提高唐氏儿和其他染色体病儿及各种畸形的诊断率,及时做出判断是否终止妊娠,为家庭和社会减轻了沉重的负担.

  16. Technical Note: Four-dimensional variational data assimilation for inverse modelling of atmospheric methane emissions: method and comparison with synthesis inversion

    Directory of Open Access Journals (Sweden)

    J. F. Meirink

    2008-06-01

    Full Text Available A four-dimensional variational (4D-var data assimilation system for inverse modelling of atmospheric methane emissions is presented. The system is based on the TM5 atmospheric transport model. It can be used for assimilating large volumes of measurements, in particular satellite observations and quasi-continuous in-situ observations, and at the same time it enables the optimization of a large number of model parameters, specifically grid-scale emission rates. Furthermore, the variational method allows to estimate uncertainties in posterior emissions. Here, the system is applied to optimize monthly methane emissions over a 1-year time window on the basis of surface observations from the NOAA-ESRL network. The results are rigorously compared with an analogous inversion by Bergamaschi et al. (2007, which was based on the traditional synthesis approach. The posterior emissions as well as their uncertainties obtained in both inversions show a high degree of consistency. At the same time we illustrate the advantage of 4D-Var in reducing aggregation errors by optimizing emissions at the grid scale of the transport model. The full potential of the assimilation system is exploited in Meirink et al. (2008, who use satellite observations of column-averaged methane mixing ratios to optimize emissions at high spatial resolution, taking advantage of the zooming capability of the TM5 model.

  17. Assimilating surface observations in a four-dimensional variational Doppler radar data assimilation system to improve the analysis and forecast of a squall line case

    Science.gov (United States)

    Chen, Xingchao; Zhao, Kun; Sun, Juanzhen; Zhou, Bowen; Lee, Wen-Chau

    2016-10-01

    This paper examines how assimilating surface observations can improve the analysis and forecast ability of a fourdimensional Variational Doppler Radar Analysis System (VDRAS). Observed surface temperature and winds are assimilated together with radar radial velocity and reflectivity into a convection-permitting model using the VDRAS four-dimensional variational (4DVAR) data assimilation system. A squall-line case observed during a field campaign is selected to investigate the performance of the technique. A single observation experiment shows that assimilating surface observations can influence the analyzed fields in both the horizontal and vertical directions. The surface-based cold pool, divergence and gust front of the squall line are all strengthened through the assimilation of the single surface observation. Three experiments—assimilating radar data only, assimilating radar data with surface data blended in a mesoscale background, and assimilating both radar and surface observations with a 4DVAR cost function—are conducted to examine the impact of the surface data assimilation. Independent surface and wind profiler observations are used for verification. The result shows that the analysis and forecast are improved when surface observations are assimilated in addition to radar observations. It is also shown that the additional surface data can help improve the analysis and forecast at low levels. Surface and low-level features of the squall line—including the surface warm inflow, cold pool, gust front, and low-level wind—are much closer to the observations after assimilating the surface data in VDRAS.

  18. Real-Space Imaging of Carrier Dynamics of Materials Surfaces by Second-Generation Four-Dimensional Scanning Ultrafast Electron Microscopy

    KAUST Repository

    Sun, Jingya

    2015-09-14

    In the fields of photocatalysis and photovoltaics, ultrafast dynamical processes, including carrier trapping and recombination on material surfaces, are among the key factors that determine the overall energy conversion efficiency. A precise knowledge of these dynamical events on the nanometer (nm) and femtosecond (fs) scales was not accessible until recently. The only way to access such fundamental processes fully is to map the surface dynamics selectively in real space and time. In this study, we establish a second generation of four-dimensional scanning ultrafast electron microscopy (4D S-UEM) and demonstrate the ability to record time-resolved images (snapshots) of material surfaces with 650 fs and ∼5 nm temporal and spatial resolutions, respectively. In this method, the surface of a specimen is excited by a clocking optical pulse and imaged using a pulsed primary electron beam as a probe pulse, generating secondary electrons (SEs), which are emitted from the surface of the specimen in a manner that is sensitive to the local electron/hole density. This method provides direct and controllable information regarding surface dynamics. We clearly demonstrate how the surface morphology, grains, defects, and nanostructured features can significantly impact the overall dynamical processes on the surface of photoactive-materials. In addition, the ability to access two regimes of dynamical probing in a single experiment and the energy loss of SEs in semiconductor-nanoscale materials will also be discussed.

  19. Dimensional Reduction of N=1, E_8 SYM over SU(3)/U(1) x U(1) x Z_3 and its four-dimensional effective action

    CERN Document Server

    Irges, Nikos; Zoupanos, George

    2011-01-01

    We present an extension of the Standard Model inspired by the E_8 x E_8 Heterotic String. In order that a reasonable effective Lagrangian is presented we neglect everything else other than the ten-dimensional N=1 supersymmetric Yang-Mills sector associated with one of the gauge factors and certain couplings necessary for anomaly cancellation. We consider a compactified space-time M_4 x B_0 / Z_3, where B_0 is the nearly-Kaehler manifold SU(3)/U(1) x U(1) and Z_3 is a freely acting discrete group on B_0. Then we reduce dimensionally the E_8 on this manifold and we employ the Wilson flux mechanism leading in four dimensions to an SU(3)^3 gauge theory with the spectrum of a N=1 supersymmetric theory. We compute the effective four-dimensional Lagrangian and demonstrate that an extension of the Standard Model is obtained with interesting features including a conserved baryon number and fixed tree level Yukawa couplings and scalar potential. The spectrum contains new states such as right handed neutrinos and heavy ...

  20. Four-dimensional magnetic resonance imaging for the determination of tumour movement and its evaluation using a dynamic porcine lung phantom

    Energy Technology Data Exchange (ETDEWEB)

    Remmert, G [Department of Medical Physics in Radiation Oncology, German Cancer Research Centre (DKFZ), 69120 Heidelberg (Germany); Biederer, J [Department of Radiology, German Cancer Research Centre (DKFZ), 69120 Heidelberg (Germany); Lohberger, F [Department of Medical Physics in Radiology, German Cancer Research Centre (DKFZ), 69120 Heidelberg (Germany); Fabel, M [Department of Radiology, German Cancer Research Centre (DKFZ), 69120 Heidelberg (Germany); Hartmann, G H [Department of Medical Physics in Radiation Oncology, German Cancer Research Centre (DKFZ), 69120 Heidelberg (Germany)

    2007-09-21

    A method of four-dimensional (4D) magnetic resonance imaging (MRI) has been implemented and evaluated. It consists of retrospective sorting and slice stacking of two-dimensional (2D) images using an external signal for motion monitoring of the object to be imaged. The presented method aims to determine the tumour trajectories based on a signal that is appropriate for monitoring the movement of the target volume during radiotherapy such that the radiation delivery can be adapted to the movement. For evaluation of the 4D-MRI method, it has been applied to a dynamic lung phantom, which exhibits periodic respiratory movement of a porcine heart-lung explant with artificial pulmonary nodules. Anatomic changes of the lung phantom caused by respiratory motion have been quantified, revealing hysteresis. The results demonstrate the feasibility of the presented method of 4D-MRI. In particular, it enables the determination of trajectories of periodically moving objects with an uncertainty in the order of 1 mm. (note)

  1. Four-dimensional magnetic resonance imaging for the determination of tumour movement and its evaluation using a dynamic porcine lung phantom.

    Science.gov (United States)

    Remmert, G; Biederer, J; Lohberger, F; Fabel, M; Hartmann, G H

    2007-09-21

    A method of four-dimensional (4D) magnetic resonance imaging (MRI) has been implemented and evaluated. It consists of retrospective sorting and slice stacking of two-dimensional (2D) images using an external signal for motion monitoring of the object to be imaged. The presented method aims to determine the tumour trajectories based on a signal that is appropriate for monitoring the movement of the target volume during radiotherapy such that the radiation delivery can be adapted to the movement. For evaluation of the 4D-MRI method, it has been applied to a dynamic lung phantom, which exhibits periodic respiratory movement of a porcine heart-lung explant with artificial pulmonary nodules. Anatomic changes of the lung phantom caused by respiratory motion have been quantified, revealing hysteresis. The results demonstrate the feasibility of the presented method of 4D-MRI. In particular, it enables the determination of trajectories of periodically moving objects with an uncertainty in the order of 1 mm.

  2. Three-dimensional electrode displacement elastography using the Siemens C7F2 fourSight four-dimensional ultrasound transducer.

    Science.gov (United States)

    Bharat, Shyam; Fisher, Ted G; Varghese, Tomy; Hall, Timothy J; Jiang, Jingfeng; Madsen, Ernest L; Zagzebski, James A; Lee, Fred T

    2008-08-01

    Because ablation therapy alters the elastic modulus of tissues, emerging strain imaging methods may enable clinicians for the first time to have readily available, cost-effective, real-time guidance to identify the location and boundaries of thermal lesions. Electrode displacement elastography is a method of strain imaging tailored specifically to ultrasound-guided electrode-based ablative therapies (e.g., radio-frequency ablation). Here tissue deformation is achieved by applying minute perturbations to the unconstrained end of the treatment electrode, resulting in localized motion around the end of the electrode embedded in tissue. In this article, we present a method for three-dimensional (3D) elastographic reconstruction from volumetric data acquired using the C7F2 fourSight four-dimensional ultrasound transducer, provided by Siemens Medical Solutions USA, Inc. (Issaquah, WA, USA). Lesion reconstruction is demonstrated for a spherical inclusion centered in a tissue-mimicking phantom, which simulates a thermal lesion embedded in a normal tissue background. Elastographic reconstruction is also performed for a thermal lesion created in vitro in canine liver using radio-frequency ablation. Postprocessing is done on the acquired raw radio-frequency data to form surface-rendered 3D elastograms of the inclusion. Elastographic volume estimates of the inclusion compare reasonably well with the actual known inclusion volume, with 3D electrode displacement elastography slightly underestimating the true inclusion volume.

  3. Application of a Four-dimensional Mathematical Model in the Establishment of an Early Post-burn Cerebral Oedema Model in Severely Burned Dogs.

    Science.gov (United States)

    Haitao, L; Dajun, Y; Kaifa, W; Xiuwu, B; Jiansen, S; Zongchen, Y

    2005-06-30

    The aim of this study was to explore the spatiotemporal development of cerebral oedema in the early stage of severe burn (50% TBSA, third degree), using a four-dimensional (4D) mathematical model. Twenty-six male mongrel dogs were randomly divided into control and 6, 12, 18, and 24 post-burn hour (PBH) groups. The manifestation of magnetic resonance imaging (MRI) and histopathology, changes of brain water content, and intracranial pressure were observed in each group respectively. A 4D mathematical model was established on the basis of the results of MRI scanning. Two turning points (6 and 18 PBH) and three phases of pathological change were displayed by the 4D mathematical model of cerebral oedema in the early stage of severe burn. The first phase was in the subclinical period, and effective treatment should therefore be performed as quickly as possible in order to prevent deterioration of post-burn cerebral oedema. The second phase (6-18 PBH), with pathological characteristics of cytotoxic cerebral oedema, was in the apoptosis period. The third stage (18-24 PBH) was the danger period of cerebral oedema. Intracranial pressure increased rapidly owing to the limitation of the cranial cavity. As a result, cerebral hernia could easily occur. An S-shape curve in the pathological process of cerebral oedema occurred in the early post-burn stage following severe burn.

  4. Stress echocardiography in patients with morbid obesity

    Directory of Open Access Journals (Sweden)

    Benoy N Shah

    2016-06-01

    Full Text Available The incidence of significant obesity is rising across the globe. These patients often have a clustering of cardiovascular risk factors and are frequently referred for noninvasive cardiac imaging tests. Stress echocardiography (SE is widely used for assessment of patients with known or suspected coronary artery disease (CAD, but its clinical utility in morbidly obese patients (in whom image quality may suffer due to body habitus has been largely unknown. The recently published Stress Ultrasonography in Morbid Obesity (SUMO study has shown that SE, when performed appropriately with ultrasound contrast agents (whether performed with physiological or pharmacological stress, has excellent feasibility and appropriately risk stratifies morbidly obese patients, including identification of patients who require revascularization. This article reviews the evidence supporting the use of echocardiographic techniques in morbidly obese patients for assessment of known or suspected CAD and briefly discusses other noninvasive modalities, including magnetic resonance and nuclear techniques, comparing and contrasting these techniques against SE.

  5. Atherosclerotic Aortic Plaques Detected by Transesophageal Echocardiography

    Institute of Scientific and Technical Information of China (English)

    赵云; 朱文玲; 倪超; 郭丽琳; 曾勇; 方理刚

    2002-01-01

    Objective To evaluate the predictive value of atherosclerotic aortic plaques in coronary artery disease (CAD) Methods In 50patients with suspected coronary artery disease, transesophageal echocardiography was performed to examine their thoracic aortas 2 weeks before or after coronary angiography. In the cases of coronary angiography studied, stenosis of the coronary artery ≥ 50 % was considered to be due to coronary artery disease,whereas the thickness of the intima ≥ 1.3 mm was taken to be the criteria for the presence of an atherosclerotic aortic plaque on the transesophageal echocardiographic test. Results Among the 50 patients, 37 cases were diagnosed as CAD and 13 cases were considered to be normal. The plaques of the thoracic aorta were observed in 34cases in the CAD group and 3 cases in the normal group. The sensitivity and specificity of aortic plaques for CAD were 91.9 % and 76.9%, respectively. The positive and negative predictive values of the aortic plaques for CAD were 91.9% and 76.9%, respectively. The accuracy was 88.0%. 80 percent of the patients with single- yes sel disease had thoracic aortic plaques, 92 percent of the patients with two-vessel disease and 100 percent of the patients with three-vessel disease had thoracic aortic plaques. There was a significant difference in the thickness of aortic intimas between the normal group and the CAD group. Conclusions Detectingatherosclerotic plaques in the thoracic aorta with transesophageal echocardiography may be of great value in predicting the presence and extent of coronary artery disease.

  6. Optimization of acquisition parameters and accuracy of target motion trajectory for four-dimensional cone-beam computed tomography with a dynamic thorax phantom.

    Science.gov (United States)

    Shimohigashi, Yoshinobu; Araki, Fujio; Maruyama, Masato; Nakaguchi, Yuji; Nakato, Kengo; Nagasue, Nozomu; Kai, Yudai

    2015-01-01

    Our purpose in this study was to evaluate the performance of four-dimensional computed tomography (4D-CBCT) and to optimize the acquisition parameters. We evaluated the relationship between the acquisition parameters of 4D-CBCT and the accuracy of the target motion trajectory using a dynamic thorax phantom. The target motion was created three dimensionally using target sizes of 2 and 3 cm, respiratory cycles of 4 and 8 s, and amplitudes of 1 and 2 cm. The 4D-CBCT data were acquired under two detector configurations: "small mode" and "medium mode". The projection data acquired with scan times ranging from 1 to 4 min were sorted into 2, 5, 10, and 15 phase bins. The accuracy of the measured target motion trajectories was evaluated by means of the root mean square error (RMSE) from the setup values. For the respiratory cycle of 4 s, the measured trajectories were within 2 mm of the setup values for all acquisition times and target sizes. Similarly, the errors for the respiratory cycle of 8 s were <4 mm. When we used 10 or more phase bins, the measured trajectory errors were within 2 mm of the setup values. The trajectory errors for the two detector configurations showed similar trends. The acquisition times for achieving an RMSE of 1 mm for target sizes of 2 and 3 cm were 2 and 1 min, respectively, for respiratory cycles of 4 s. The results obtained in this study enable optimization of the acquisition parameters for target size, respiratory cycle, and desired measurement accuracy.

  7. Cerebral blood flow in a healthy Circle of Willis and two intracranial aneurysms: computational fluid dynamics versus four-dimensional phase-contrast magnetic resonance imaging.

    Science.gov (United States)

    Berg, Philipp; Stucht, Daniel; Janiga, Gábor; Beuing, Oliver; Speck, Oliver; Thévenin, Dominique

    2014-04-01

    Computational fluid dynamics (CFD) opens up multiple opportunities to investigate the hemodynamics of the human vascular system. However, due to numerous assumptions the acceptance of CFD among physicians is still limited in practice and validation through comparison is mandatory. Time-dependent quantitative phase-contrast magnetic resonance imaging PC-MRI measurements in a healthy volunteer and two intracranial aneurysms were carried out at 3 and 7 Tesla. Based on the acquired images, three-dimensional (3D) models of the aneurysms were reconstructed and used for the numerical simulations. Flow information from the MR measurements were applied as boundary conditions. The four-dimensional (4D) velocity fields obtained by CFD and MRI were qualitatively as well as quantitatively compared including cut planes and vector analyses. For all cases a high similarity of the velocity patterns was observed. Additionally, the quantitative analysis revealed a good agreement between CFD and MRI. Deviations were caused by minor differences between the reconstructed vessel models and the actual lumen. The comparisons between diastole and systole indicate that relative differences between MRI and CFD are intensified with increasing velocity. The findings of this study lead to the conclusion that CFD and MRI agree well in predicting intracranial velocities when realistic geometries and boundary conditions are provided. Due to the considerably higher temporal and spatial resolution of CFD compared to MRI, complex flow patterns can be further investigated in order to evaluate their role with respect to aneurysm formation or rupture. Nevertheless, special care is required regarding the vessel reconstruction since the geometry has a major impact on the subsequent numerical results.

  8. Four-dimensional noise reduction using the time series of medical computed tomography datasets with short interval times: a static-phantom study

    Directory of Open Access Journals (Sweden)

    Tatsuya Nishii

    2016-02-01

    Full Text Available Backgrounds. This study examines the hypothesis that four-dimensional noise reduction (4DNR with short interval times reduces noise in cardiac computed tomography (CCT using “padding” phases. Furthermore, the capability of reducing the reduction dose in CCT using this post-processing technique was assessed. Methods. Using base and quarter radiation doses for CCT (456 and 114 mAs/rot with 120 kVp, a static phantom was scanned ten times with retrospective electrocardiogram gating, and 4DNR with short interval times (50 ms was performed using a post-processing technique. Differences in the computed tomography (CT attenuation, contrast-to-noise ratio (CNR and spatial resolution with modulation transfer function in each dose image obtained with and without 4DNR were assessed by conducting a Tukey–Kramer’s test and non-inferiority test. Results. For the base dose, by using 4DNR, the CNR was improved from 1.18 ± 0.15 to 2.08 ± 0.20 (P = 0.001, while the CT attenuation and spatial resolution of the image of 4DNR did not were significantly inferior to those of reference image (P < 0.001. CNRs of the quarter-dose image in 4DNR also improved to 1.28 ± 0.11, and were not inferior to those of the non-4DNR images of the base dose (P < 0.001. Conclusions. 4DNR with short interval times significantly reduced noise. Furthermore, applying this method to CCT would have the potential of reducing the radiation dose by 75%, while maintaining a similar image noise level.

  9. Detection of residual brain arteriovenous malformations after radiosurgery: diagnostic accuracy of contrast-enhanced four-dimensional MR angiography at 3.0 T

    Science.gov (United States)

    Lim, H K; Choi, C G; Kim, S M; Kim, J L; Lee, D H; Kim, S J; Suh, D C

    2012-01-01

    Objective To evaluate the diagnostic accuracy of four-dimensional MR angiography (4D-MRA) at 3.0 T for detecting residual arteriovenous malformations (AVMs) after Gamma Knife® (Elekta Instrument AB, Stockholm, Sweden) radiosurgery (GKRS). Methods We assessed 36 angiographically confirmed AVMs in 36 patients who had been treated with GKRS. 4D-MRA was performed after GKRS and the time intervals were 39.4±26.0 months [mean±standard deviation (SD)]. 4D-MRA was obtained at 3.0 T after contrast injection, with a measured voxel size of 1×1×1 mm and a temporal resolution of 1.1 s (13 patients) or a voxel size of 1×1×2 mm and a temporal resolution of 0.98 s (23 patients). X-ray angiography was performed as the standard reference within 53±47 days (mean±SD) after MRA. To determine a residual AVM, the 4D-MRA results were independently reviewed by two readers blinded to the X-ray angiography results. We evaluated diagnostic sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of 4D-MRA for detection of a residual AVM. Results A residual AVM was identified in 13 patients (13/36, 36%) on X-ray angiography. According to Readers 1 and 2, 4D-MRA had a sensitivity of 79.6% and 64.3%, a specificity of 90.9% and 100%, a PPV of 84.6% and 100% and an NPV of 90% and 81.5%, respectively, and a diagnostic accuracy of 86.1% for Readers 1 and 2, for detecting residual AVMs after GKRS. Conclusion The diagnostic accuracy of 4D-MRA at 3.0 T seems high, but there is still the possibility of further improving the spatiotemporal resolution of this technique. PMID:22294705

  10. To what extent does the anxiety scale of the Four-Dimensional Symptom Questionnaire (4DSQ) detect specific types of anxiety disorder in primary care? A psychometric study

    Science.gov (United States)

    2014-01-01

    Background Anxiety scales may help primary care physicians to detect specific anxiety disorders among the many emotionally distressed patients presenting in primary care. The anxiety scale of the Four-Dimensional Symptom Questionnaire (4DSQ) consists of an admixture of symptoms of specific anxiety disorders. The research questions were: (1) Is the anxiety scale unidimensional or multidimensional? (2) To what extent does the anxiety scale detect specific DSM-IV anxiety disorders? (3) Which cut-off points are suitable to rule out or to rule in (which) anxiety disorders? Methods We analyzed 5 primary care datasets with standardized psychiatric diagnoses and 4DSQ scores. Unidimensionality was assessed through confirmatory factor analysis (CFA). We examined mean scores and anxiety score distributions per disorder. Receiver operating characteristic (ROC) analysis was used to determine optimal cut-off points. Results Total n was 969. CFA supported unidimensionality. The anxiety scale performed slightly better in detecting patients with panic disorder, agoraphobia, social phobia, obsessive compulsive disorder (OCD) and post traumatic stress disorder (PTSD) than patients with generalized anxiety disorder (GAD) and specific phobia. ROC-analysis suggested that ≥4 was the optimal cut-off point to rule out and ≥10 the cut-off point to rule in anxiety disorders. Conclusions The 4DSQ anxiety scale measures a common trait of pathological anxiety that is characteristic of anxiety disorders, in particular panic disorder, agoraphobia, social phobia, OCD and PTSD. The anxiety score detects the latter anxiety disorders to a slightly greater extent than GAD and specific phobia, without being able to distinguish between the different anxiety disorder types. The cut-off points ≥4 and ≥10 can be used to separate distressed patients in three groups with a relatively low, moderate and high probability of having one or more anxiety disorders. PMID:24761829

  11. Temporal averaging for analysis of four-dimensional whole-heart computed tomography perfusion of the myocardium: proof-of-concept study.

    Science.gov (United States)

    Feger, S; Shaban, A; Lukas, S; Kendziorra, C; Rief, M; Zimmermann, E; Dewey, M

    2017-03-01

    To assess the feasibility of four-dimensional (4D) whole-heart computed tomography perfusion (CTP) of the myocardium and the added value of temporal averaging of consecutive 3D datasets from different heartbeats for analysis. We included 30 patients with suspected or known coronary artery disease (CAD) who underwent 320-row coronary CT angiography (CTA) and myocardial CTP. Out of these, 15 patients underwent magnetic resonance myocardial perfusion imaging (MR MPI). All CTP examinations were initiated after 3 min of intravenous infusion of adenosine (140 µg/kg/min) and were performed dynamically covering the entire heart every heart beat over a period of 20 ± 3 heart beats. Temporal averaging for dynamic CTP visualisation was analysed for the combination of two, three, four, six, and eight consecutive 3D datasets. Input time attenuation curves (TAC) were delivered from measurement points in the centre of the left ventricle. In all 30 patients, myocardial 4D CTP was feasible and temporal averaging was successfully implemented for all planned combinations of 3D datasets. Temporal averaging of three consecutive 3D datasets showed best performance in the analysis of all CTP image quality parameters: noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), subjective image quality, and diagnostic accuracy with an improvement of SNR and CNR by a factor of 2.2 ± 1.3 and 1.3 ± 0.9. With increasing level of temporal averaging, the input TACs became smoother, but also shorter. Out of the 11 perfusion defects detected with MR MPI, 9 defects were also visible on the 4D CTP images. Whole-heart CTP of the myocardium is feasible and temporal averaging of dynamic datasets improves quantitative image quality parameters and visualization of perfusion defects while further studies are needed to assess its added value for quantification of perfusion parameters.

  12. MR selective flow-tracking cartography: a postprocessing procedure applied to four-dimensional flow MR imaging for complete characterization of cranial dural arteriovenous fistulas.

    Science.gov (United States)

    Edjlali, Myriam; Roca, Pauline; Rabrait, Cécile; Trystram, Denis; Rodriguez-Régent, Christine; Johnson, Kevin M; Wieben, Oliver; Turski, Patrick; Meder, Jean-François; Naggara, Olivier; Oppenheim, Catherine

    2014-01-01

    To assess the feasibility of a selective flow-tracking cartographic procedure applied to four-dimensional (4D) flow imaging and to demonstrate its usefulness in the characterization of dural arteriovenous fistulas (DAVFs). Institutional review board approval was obtained, and all patients provided written informed consent. Eight patients (nine DAVFs) underwent 3.0-T magnetic resonance (MR) imaging and digital subtraction angiography (DSA). Imaging examinations were performed within 24 hours of each other. 4D flow MR imaging was performed by using a 4D radial phase-contrast vastly undersampled isotropic projection reconstruction pulse sequence with an isotropic spatial resolution of 0.86 mm (5 minutes 35 seconds). Two radiologists independently reviewed images from MR flow-tracking cartography and reported the location of arterial feeder vessels and the venous drainage type and classified DAVFs according to the risk of rupture (Cognard classification). These results were compared with those at DSA. Quadratic weighted κ statistics with their 95% confidence intervals (CIs) were used to test intermodality agreement in the identification of arterial feeder vessels, draining veins, and Cognard classification. Interreader agreement for shunt location on MR images was perfect (κ = 1), with good-to-excellent interreader agreement for arterial feeder vessel identification (κ = 0.97; 95% CI = 0.92, 1.0), and matched in all cases with shunt location defined at DSA. There was good-to-excellent agreement between MR cartography and DSA in the definition of the main feeding arteries (κ = 0.92; 95% CI = 0.83, 1.0), presence of retrograde flow in dural sinuses (κ = 1), presence of retrograde cortical venous drainage (κ = 1), presence of venous ectasia (κ = 1), and final Cognard classification of DAVFs (κ = 1, standard error = 0.35). MR selective flow-tracking cartography enabled the noninvasive characterization of cranial DAVFs. © RSNA, 2013.

  13. Clinical assessment of transthoracic echocardiography skills: a generalizability study

    DEFF Research Database (Denmark)

    Nielsen, Dorte Guldbrand; O'Neill, Lotte; Jensen, Signe

    2015-01-01

    Context: Transthoracic echocardiography (TTE) is a widely used cardiac imaging technique that all cardiologists should be able to perform competently. Traditionally, TTE competence has been assessed by unstructured observation or in test situations separated from daily clinical practice. An objec...

  14. Intra-cardiac echocardiography in alcohol septal ablation

    DEFF Research Database (Denmark)

    Cooper, Robert M; Shahzad, Adeel; Newton, James;

    2015-01-01

    Alcohol septal ablation (ASA) in hypertrophic obstructive cardiomyopathy reduces left ventricular outflow tract gradients. A third of patients do not respond; inaccurate localisation of the iatrogenic infarct can be responsible. Transthoracic echocardiography (TTE) using myocardial contrast can b...

  15. Trans-esophageal echocardiography for tricuspid and pulmonary valves

    Directory of Open Access Journals (Sweden)

    Prabhu Mahesh

    2009-01-01

    Full Text Available Transesophageal echocardiography has been shown to provide unique information about cardiac anatomy, function, hemodynamics and blood flow and is relatively easy to perform with a low risk of complications. Echocardiographic evaluation of the tricuspid and pulmonary valves can be achieved with two-dimensional and Doppler imaging. Transesophageal echocardiography of these valves is more challenging because of their complex structure and their relative distance from the esophagus. Two-dimensional echocardiography allows an accurate visualization of the cardiac chambers and valves and their motion during the cardiac cycle. Doppler echocardiography is the most commonly used diagnostic technique for detecting and evaluating valvular regurgitation. The lack of good quality evidence makes it difficult to recommend a validated quantitative approach but expert consensus recommends a clinically useful qualitative approach. This review ennumerates probe placement, recommended cross-sectional views, flow patterns, quantitative equations including the clinical approach to the noninvasive quantification of both stenotic and regurgitant lesions.

  16. Speckle tracking echocardiography in acute lupus myocarditis: comparison to conventional echocardiography

    Directory of Open Access Journals (Sweden)

    Riëtte Du Toit

    2017-07-01

    Full Text Available Aims: Lupus myocarditis occurs in 5–10% of patients with systemic lupus erythematosus (SLE. No single feature is diagnostic of lupus myocarditis. Speckle tracking echocardiography (STE can detect subclinical left ventricular dysfunction in SLE patients, with limited research on its utility in clinical lupus myocarditis. We report on STE in comparison to conventional echocardiography in patients with clinical lupus myocarditis. Methods and results: A retrospective study was done at a tertiary referral hospital in South Africa. SLE patients with lupus myocarditis were included and compared to healthy controls. Echocardiographic images were reanalyzed, including global longitudinal strain through STE. A poor echocardiographic outcome was defined as final left ventricular ejection fraction (LVEF <40%. 28 SLE patients fulfilled the criteria. Global longitudinal strain correlated with global (LVEF: r = −0.808; P = 0.001 and regional (wall motion score: r = 0.715; P < 0.001 function. In patients presenting with a LVEF ≥50%, global longitudinal strain (P = 0.023, wall motion score (P = 0.005 and diastolic function (P = 0.004 were significantly impaired vs controls. Following treatment, LVEF (35–47% (P = 0.023 and wall motion score (1.88–1.5 (P = 0.017 improved but not global longitudinal strain. Initial LVEF (34%; P = 0.046 and global longitudinal strain (−9.5%; P = 0.095 were lower in patients with a final LVEF <40%. Conclusions: This is the first known report on STE in a series of patients with clinical lupus myocarditis. Global longitudinal strain correlated with regional and global left ventricular function. Global longitudinal strain, wall motion score and diastolic parameters may be more sensitive markers of lupus myocarditis in patients presenting with a preserved LVEF ≥50%. A poor initial LVEF and global longitudinal strain were associated with a persistent LVEF <40%. Echocardiography is a non-invasive tool with diagnostic and

  17. Avoiding transthoracic echocardiography and transesophageal echocardiography for patients with variable body mass indexes in infective endocarditis

    Directory of Open Access Journals (Sweden)

    Robert Sogomonian

    2016-04-01

    Full Text Available Background: Echocardiography has been a popular modality used to aid in the diagnosis of infective endocarditis (IE with the modified Duke criteria. We evaluated the necessity between the uses of either a transthoracic echocardiography (TTE or transesophageal echocardiography (TEE in patients with a body mass index (BMI greater than or equal to 25 kg/m2 and less than 25 kg/m2. Methods: A single-centered, retrospective study of 198 patients between 2005 and 2012 diagnosed with IE based on modified Duke criteria. Patients, required to be above age 18, had undergone an echocardiogram study and had blood cultures to be included in the study. Results: Among 198 patients, two echocardiographic groups were evaluated as 158 patients obtained a TTE, 143 obtained a TEE, and 103 overlapped with TEE and TTE. Out of these patients, 167 patients were included in the study as 109 (65% were discovered to have native valve vegetations on TEE and 58 (35% with TTE. TTE findings were compared with TEE results for true negatives and positives to isolate valvular vegetations. Overall sensitivity of TTE was calculated to be 67% with a specificity of 93%. Patients were further divided into two groups with the first group having a BMI ≥25 kg/m2 and the subsequent group with a BMI <25 kg/m2. Patients with a BMI ≥25 kg/m2 who underwent a TTE study had a sensitivity and specificity of 54 and 92%, respectively. On the contrary, patients with a BMI < 25 kg/m2 had a TTE sensitivity and specificity of 78 and 95%, respectively. Conclusions: Patients with a BMI <25 kg/m2 and a negative TTE should refrain from further diagnostic studies, with TEE strong clinical judgment is warranted. Patients with a BMI ≥ 25 kg/m2 may proceed directly to TEE as the initial study, possibly avoiding an additional study with a TTE.

  18. Dobutamine stress echocardiography in healthy adult male rats

    OpenAIRE

    Couet Jacques; Roussel Élise; Drolet Marie-Claude; Lachance Dominic; Plante Eric; Arsenault Marie

    2005-01-01

    Abstract Background Dobutamine stress echocardiography is used to investigate a wide variety of heart diseases in humans. Dobutamine stress echocardiography has also been used in animal models of heart disease despite the facts that the normal response of healthy rat hearts to this type of pharmacological stress testing is unknown. This study was performed to assess this normal response. Methods 15 normal adult male Wistar rats were evaluated. Increasing doses of dobutamine were infused intra...

  19. Minimally invasive cardiac surgery and transesophageal echocardiography

    Directory of Open Access Journals (Sweden)

    Ajay Kumar Jha

    2014-01-01

    Full Text Available Improved cosmetic appearance, reduced pain and duration of post-operative stay have intensified the popularity of minimally invasive cardiac surgery (MICS; however, the increased risk of stroke remains a concern. In conventional cardiac surgery, surgeons can visualize and feel the cardiac structures directly, which is not possible with MICS. Transesophageal echocardiography (TEE is essential during MICS in detecting problems that require immediate correction. Comprehensive evaluation of the cardiac structures and function helps in the confirmation of not only the definitive diagnosis, but also the success of surgical treatment. Venous and aortic cannulations are not under the direct vision of the surgeon and appropriate positioning of the cannulae is not possible during MICS without the aid of TEE. Intra-operative TEE helps in the navigation of the guide wire and correct placement of the cannulae and allows real-time assessment of valvular pathologies, ventricular filling, ventricular function, intracardiac air, weaning from cardiopulmonary bypass and adequacy of the surgical procedure. Early detection of perioperative complications by TEE potentially enhances the post-operative outcome of patients managed with MICS.

  20. Biplane transesophageal echocardiography in the normal cat.

    Science.gov (United States)

    Kienle, R D; Thomas, W P; Rishniw, M

    1997-01-01

    Eight healthy, adult cats were examined with biplane transesophageal echocardiography (TEE). Cats were sedated with a combination of diazepam and propofol and were examined using a 5 mm x 80 cm pediatric biplane TEE probe. Consistent images were obtained at three imaging depths within the esophagus. The caudal position provided satisfactory short-axis images of the left ventricle and heart base. The middle position provided the best long-axis views of the left atrium, left ventricle, and aorta and allowed Doppler examination of transmitral left ventricular inflow. The cranial position provided satisfactory imaging of the aorta and pulmonary artery and allowed Doppler examination of right ventricular and left ventricular outflow. Biplane TEE provides an additional method of imaging the feline heart which is complimentary to other imaging techniques and the images obtained were similar to those reported for dogs. Although TEE offers a slight advantage over transthorcic imaging for Doppler examination, the quality of the images of heart base structures was not as consistently superior to transthoracic images in cats as reported in dogs.

  1. Transoesophageal echocardiography: What a neuroanaesthesiologist should know?

    Directory of Open Access Journals (Sweden)

    Minati Choudhury

    2015-01-01

    Full Text Available Transoesophageal echocardiography (TEE is a semi invasive imaging modality rapidly gained credence and popularity in the cardiothoracic centers worldwide by mid 1990s. It has also been found to be useful in some noncardiac surgical procedures, in particular in the management of neurosurgical patients and haemodynamically unstable patients in intensive care units (ICUs. The principal goal of basic transoesophageal echocardiographic examination encompass a broad range of anatomic imaging including the diagnosis of air embolism, causes of haemodynamic instability, ventricular size and function, volume status, and complications from invasive procedures, as well as the clinical impact or etiology of pulmonary dysfunction in ICU. TEE is relatively cheap and semi-invasive, but it should not be used as a stand-alone device but as a tool which provides data in addition to the data acquired from other forms of monitoring. The establishment of TEE in perioperative neuro anaesthetic care though recent, may result in a significant change in the role of the anaesthetsiologist who, using TEE can provide new information which may change the course and the outcome of surgical procedures.

  2. Echocardiography in chronic liver disease: systematic review.

    Science.gov (United States)

    Mota, Vitor Gomes; Markman Filho, Brivaldo

    2013-04-01

    Doppler echocardiography (Echo) is a non-invasive method of excellent accuracy to screen portopulmonary hypertension (PPH) and to assess intrapulmonary shunts (IPS) in chronic liver disease (CLD). In the past decade, Echo proved to play a fundamental role in the diagnosis of cirrhotic cardiomyopathy (CCM). To perform a systematic review of relevant articles on the subject 'Echo in CLD'. In November 2011, a systematic review was performed in the PubMed, LILACS and SciELO databases, and the characteristics of the studies selected were reported. The search based on descriptors and free terms obtained 204 articles (179 in Pubmed, 21 in LILACS, and 1 in SciELO). Of those 204 articles, 22 were selected for systematic review. A meta-analysis could not be performed because of the heterogeneity of the articles. Echo should be part of CLD stratification for screening PPH, IPS and CCM, because, most of the time, such complications are diagnosed only when patients are already waiting for a liver transplant.

  3. Dynamic 3D echocardiography in virtual reality

    Directory of Open Access Journals (Sweden)

    Simoons Maarten L

    2005-12-01

    Full Text Available Abstract Background This pilot study was performed to evaluate whether virtual reality is applicable for three-dimensional echocardiography and if three-dimensional echocardiographic 'holograms' have the potential to become a clinically useful tool. Methods Three-dimensional echocardiographic data sets from 2 normal subjects and from 4 patients with a mitral valve pathological condition were included in the study. The three-dimensional data sets were acquired with the Philips Sonos 7500 echo-system and transferred to the BARCO (Barco N.V., Kortrijk, Belgium I-space. Ten independent observers assessed the 6 three-dimensional data sets with and without mitral valve pathology. After 10 minutes' instruction in the I-Space, all of the observers could use the virtual pointer that is necessary to create cut planes in the hologram. Results The 10 independent observers correctly assessed the normal and pathological mitral valve in the holograms (analysis time approximately 10 minutes. Conclusion this report shows that dynamic holographic imaging of three-dimensional echocardiographic data is feasible. However, the applicability and use-fullness of this technology in clinical practice is still limited.

  4. Microlesions induced by microcavitation during contrast echocardiography

    Science.gov (United States)

    Miller, Douglas; Li, Peng; Gordon, David; Armstrong, William

    2001-05-01

    The purpose of this study was to search for histologically identifiable lesions associated with myocardial contrast echocardiography (MCE) in rats. Diagnostic ultrasound scans with 1:4 end-systolic triggering provided a short-axis view of the left ventricle in rats at 1.5 MHz with 1.45-μs pulses of 1.7 Mechanical Index. Two relatively high doses (500 μl/kg) of OptisonTM ultrasound contrast agent were given 5 min apart during 10 min of MCE. One day after scanning, rats were sacrificed and the hearts fixed for histology. Slides were scored blind by a pathologist, and photomicrographs in the anterior half of the heart sections were characterized by digital image analysis. Microlesions identified by inflammatory infiltrates were scattered primarily over the anterior half of the sections. Pathologically, there was inflammatory cell infiltration in areas of 0.6+/-0.5% of the sections for shams and 3.6+/-3.6% for MCE (P<0.01). Analysis of the photographs from the anterior wall found microlesion areas of 0.5+/-0.8% for shams and 7.4+/-5.0% for MCE (P<0.02). Diagnostic MCE at high Mechanical Index has a potential for causing microscale lesions in the myocardium by nucleation of microcavitation. [Work supported by NIH Grant EB0338.

  5. Comparison of low-dose sequences of dual-source CT and echocardiography for preoperative evaluation of aortic valve disease

    Institute of Scientific and Technical Information of China (English)

    FENG Juan; WANG Xi-ming; JI Xiao-peng; LI Hai-ou; LI Qiao; GUO Wen-bin; WANG Zheng-jun

    2013-01-01

    Background Accurate evaluation of coronary artery,aortic valve annulus diameter (AVAD),and cardiac function in patients with aortic valve disease is of great significance for surgical strategy.In this study,we explored the preoperative evaluation of low-dose sequence (MinDose sequence) scan of dual-source CT (DSCT) for those patients.Methods Forty patients suspected for aortic valve disease (the experimental group) underwent MinDose sequence of DSCT to observe coronary artery,AVAD,and left ventricular ejection fraction (LVEF).Another 33 subjects suspected for coronary artery disease (the control group) underwent conventional retrospective electrocardiographically-gated sequence of DSCT.Two-dimensional transthoracic echocardiography (2D-TTE) and four-dimensional transthoracic echocardiography (4D-TTE) were applied in the experimental group to measure AVAD and LVEF and compared with MinDose-DSCT.Results There was a strong correlation between LVEFs measured by 2D-TTE and MinDose-DSCT (r=0.87,P <0.01),as well as between 4D-TTE and MinDose-DSCT (r=0.90,P <0.01).AVAD measured by MinDose-DSCT was in good agreement with corresponding measurements by 2D-TTE (r=0.90,P <0.01).The effective dose in the experimental group was 63.54% lower than that in the control group.Conclusions MinDose sequence of DSCT with a low radiation dose serving as a one-stop preoperative evaluation makes effective assessment of the coronary artery,AVAD,and LVEF for patients with aortic valve disease.

  6. Usefulness and limitations of transthoracic echocardiography in heart transplantation recipients

    Directory of Open Access Journals (Sweden)

    Galderisi Maurizio

    2008-01-01

    Full Text Available Abstract Transthoracic echocardiography is a primary non-invasive modality for investigation of heart transplant recipients. It is a versatile tool which provides comprehensive information about cardiac structure and function. Echocardiographic examinations can be easily performed at the bedside and serially repeated without any patient's discomfort. This review highlights the usefulness of Doppler echocardiography in the assessment of left ventricular and right ventricular systolic and diastolic function, of left ventricular mass, valvular heart disease, pulmonary arterial hypertension and pericardial effusion in heart transplant recipients. The main experiences performed by either standard Doppler echocardiography and new high-tech ultrasound technologies are summarised, pointing out advantages and limitations of the described techniques in diagnosing acute allograft rejection and cardiac graft vasculopathy. Despite the sustained efforts of echocardiographic technique in predicting the biopsy state, endocardial myocardial biopsies are still regarded as the gold standard for detection of acute allograft rejection. Conversely, stress echocardiography is able to identify accurately cardiac graft vasculopathy and has a recognised prognostic in this clinical setting. A normal stress-echo justifies postponement of invasive studies. Another use of transthoracic echocardiography is the monitorisation and the visualisation of the catheter during the performance of endomyocardial biopsy. Bedside stress echocardiography is even useful to select appropriately heart donors with brain death. The ultrasound monitoring is simple and effective for monitoring a safe performance of biopsy procedures.

  7. SU-E-J-110: Dosimetric Analysis of Respiratory Motion Based On Four-Dimensional Dose Accumulation in Liver Stereotactic Body Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kang, S; Kim, D; Kim, T; Kim, K; Cho, M; Shin, D; Suh, T [The Catholic University of Korea College of Medicine, Seoul (Korea, Republic of); Kim, S [Virginia Commonwealth University, Richmond, VA (United States); Park, S [Uijeongbu St.Mary’s Hospital, GyeongGi-Do (Korea, Republic of)

    2015-06-15

    Purpose: Respiratory motion in thoracic and abdominal region could lead to significant underdosing of target and increased dose to healthy tissues. The aim of this study is to evaluate the dosimetric effect of respiratory motion in conventional 3D dose by comparing 4D deformable dose in liver stereotactic body radiotherapy (SBRT). Methods: Five patients who had previously treated liver SBRT were included in this study. Four-dimensional computed tomography (4DCT) images with 10 phases for all patients were acquired on multi-slice CT scanner (Siemens, Somatom definition). Conventional 3D planning was performed using the average intensity projection (AIP) images. 4D dose accumulation was calculated by summation of dose distribution for all phase images of 4DCT using deformable image registration (DIR) . The target volume and normal organs dose were evaluated with the 4D dose and compared with those from 3D dose. And also, Index of achievement (IOA) which assesses the consistency between planned dose and prescription dose was used to compare target dose distribution between 3D and 4D dose. Results: Although the 3D dose calculation considered the moving target coverage, significant differences of various dosimetric parameters between 4D and 3D dose were observed in normal organs and PTV. The conventional 3D dose overestimated dose to PTV, however, there was no significant difference for GTV. The average difference of IOA which become ‘1’ in an ideal case was 3.2% in PTV. The average difference of liver and duodenum was 5% and 16% respectively. Conclusion: 4D dose accumulation which can provide dosimetric effect of respiratory motion has a possibility to predict the more accurate delivered dose to target and normal organs and improve treatment accuracy. This work was supported by the Radiation Technology R&D program (No. 2013M2A2A7043498) and the Mid-career Researcher Program (2014R1A2A1A10050270) through the National Research Foundation of Korea funded by the

  8. Real-time respiration monitoring using the radiotherapy treatment beam and four-dimensional computed tomography (4DCT)--a conceptual study.

    Science.gov (United States)

    Lu, Weiguo; Ruchala, Kenneth J; Chen, Ming-Li; Chen, Quan; Olivera, Gustavo H

    2006-09-21

    Real-time knowledge of intra-fraction motion, such as respiration, is essential for four-dimensional (4D) radiotherapy. Surrogate-based and internal-fiducial-based methods may suffer from one or many drawbacks such as false correlation, being invasive, delivering extra patient radiation, and requiring complicated hardware and software development and implementation. In this paper we develop a simple non-surrogate, non-invasive method to monitor respiratory motion during radiotherapy treatments in real time. This method directly utilizes the treatment beam and thus imposes no additional radiation to the patient. The method requires a pre-treatment 4DCT and a real-time detector system. The method combines off-line processes with on-line processes. The off-line processes include 4DCT imaging and pre-calculating detector signals at each phase of the 4DCT based on the planned fluence map and the detector response function. The on-line processes include measuring detector signal from the treatment beam, and correlating the measured detector signal with the pre-calculated signals. The respiration phase is determined as the position of peak correlation. We tested our method with extensive simulations based on a TomoTherapy machine and a 4DCT of a lung cancer patient. Three types of simulations were implemented to mimic the clinical situations. Each type of simulation used three different TomoTherapy delivery sinograms, each with 800 to 1000 projections, as input fluences. Three arbitrary breathing patterns were simulated and two dose levels, 2 Gy/fraction and 2 cGy/fraction, were used for simulations to study the robustness of this method against detector quantum noise. The algorithm was used to determine the breathing phases and this result was compared with the simulated breathing patterns. For the 2 Gy/fraction simulations, the respiration phases were accurately determined within one phase error in real time for most projections of the treatment, except for a few

  9. Development of an ultrasmall C-band linear accelerator guide for a four-dimensional image-guided radiotherapy system with a gimbaled x-ray head.

    Science.gov (United States)

    Kamino, Yuichiro; Miura, Sadao; Kokubo, Masaki; Yamashita, Ichiro; Hirai, Etsuro; Hiraoka, Masahiro; Ishikawa, Junzo

    2007-05-01

    We are developing a four-dimensional image-guided radiotherapy system with a gimbaled x-ray head. It is capable of pursuing irradiation and delivering irradiation precisely with the help of an agile moving x-ray head on the gimbals. Requirements for the accelerator guide were established, system design was developed, and detailed design was conducted. An accelerator guide was manufactured and basic beam performance and leakage radiation from the accelerator guide were evaluated at a low pulse repetition rate. The accelerator guide including the electron gun is 38 cm long and weighs about 10 kg. The length of the accelerating structure is 24.4 cm. The accelerating structure is a standing wave type and is composed of the axial-coupled injector section and the side-coupled acceleration cavity section. The injector section is composed of one prebuncher cavity, one buncher cavity, one side-coupled half cavity, and two axial coupling cavities. The acceleration cavity section is composed of eight side-coupled nose reentrant cavities and eight coupling cavities. The electron gun is a diode-type gun with a cerium hexaboride (CeB6) direct heating cathode. The accelerator guide can be operated without any magnetic focusing device. Output beam current was 75 mA with a transmission efficiency of 58%, and the average energy was 5.24 MeV. Beam energy was distributed from 4.95 to 5.6 MeV. The beam profile, measured 88 mm from the beam output hole on the axis of the accelerator guide, was 0.7 mm X 0.9 mm full width at half maximum (FWHM) width. The beam loading line was 5.925 (MeV)-Ib (mA) X 0.00808 (MeV/mA), where Ib is output beam current. The maximum radiation leakage of the accelerator guide at 100 cm from the axis of the accelerator guide was calculated as 0.33 cGy/min at the rated x-ray output of 500 cGy/min from the measured value. This leakage requires no radiation shielding for the accelerator guide itself per IEC 60601-2-1.

  10. The Four-Dimensional Symptom Questionnaire (4DSQ: a validation study of a multidimensional self-report questionnaire to assess distress, depression, anxiety and somatization

    Directory of Open Access Journals (Sweden)

    van Balkom Anton JLM

    2006-08-01

    Full Text Available Abstract Background The Four-Dimensional Symptom Questionnaire (4DSQ is a self-report questionnaire that has been developed in primary care to distinguish non-specific general distress from depression, anxiety and somatization. The purpose of this paper is to evaluate its criterion and construct validity. Methods Data from 10 different primary care studies have been used. Criterion validity was assessed by comparing the 4DSQ scores with clinical diagnoses, the GPs' diagnosis of any psychosocial problem for Distress, standardised psychiatric diagnoses for Depression and Anxiety, and GPs' suspicion of somatization for Somatization. ROC analyses and logistic regression analyses were used to examine the associations. Construct validity was evaluated by investigating the inter-correlations between the scales, the factorial structure, the associations with other symptom questionnaires, and the associations with stress, personality and social functioning. The factorial structure of the 4DSQ was assessed through confirmatory factor analysis (CFA. The associations with other questionnaires were assessed with Pearson correlations and regression analyses. Results Regarding criterion validity, the Distress scale was associated with any psychosocial diagnosis (area under the ROC curve [AUC] 0.79, the Depression scale was associated with major depression (AUC = 0.83, the Anxiety scale was associated with anxiety disorder (AUC = 0.66, and the Somatization scale was associated with the GPs' suspicion of somatization (AUC = 0.65. Regarding the construct validity, the 4DSQ scales appeared to have considerable inter-correlations (r = 0.35-0.71. However, 30–40% of the variance of each scale was unique for that scale. CFA confirmed the 4-factor structure with a comparative fit index (CFI of 0.92. The 4DSQ scales correlated with most other questionnaires measuring corresponding constructs. However, the 4DSQ Distress scale appeared to correlate with some other

  11. WE-D-BRA-03: Four-Dimensional Dose Reconstruction Through Retrospective Phase Determination Using Cine Images of Electronic Portal Imaging Device

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, J; Jung, J [East Carolina University, Greenville, NC (United States); Yi, B [Univ. of Maryland School Of Medicine, Baltimore, MD (United States); Kim, J [University of Pittsburgh Medical Center, Pittsburgh, PA (United States); Yeo, I [Loma Linda Univ Medical Center, Loma Linda, CA (United States)

    2015-06-15

    Purpose: To test a method to reconstruct a four-dimensional (4D) dose distribution using the correlation of pre-calculated 4D electronic portal imaging device (EPID) images and measured cine-EPID images. Methods: 1. A phantom designed to simulate a tumor in lung (a polystyrene block with 3.0 cm diameter embedded in cork) was placed on a sinusoidally moving platform with 2 cm amplitude and 4 sec/cycle. Ten-phase 4D CT images were acquired for treatment planning and dose reconstruction. A 6MV photon beam was irradiated on the phantom with static (field size=5×8.5 cm{sup 2}) and dynamic fields (sliding windows, 10×10 cm{sup 2}, X1 MLC closing in parallel with the tumor movement). 2. 4D and 3D doses were calculated forwardly on PTV (1 cm margin). 3. Dose images on EPID under the fields were calculated for 10 phases. 4. Cine EPID images were acquired during irradiation. 5. Their acquisition times were correlated to the phases of the phantom at which irradiation occurred by inter-comparing calculated “reference” EPID images with measured images (2D gamma comparison). For the dynamic beam, the tumor was hidden under MLCs during a portion of irradiation time; the correlation performed when the tumor was visible was extrapolated. 6. Dose for each phase was reconstructed on the 4D CT images and summed over all phases. The summation was compared with forwardly calculated 4D and 3D dose distributions. Monte Carlo methods were used for all calculations. Results: For the open and dynamic beams, the 4D reconstructed doses showed the pass rates of 92.7 % and 100 %, respectively, at the isocenter plane given 3% / 3 mm criteria. The better agreement of the dynamic beam was from its dose gradient which blurred the otherwise sharp difference between forward and reconstructed doses. This also contributed slightly better agreement in DVH of PTV. Conclusion: The feasibility of 4D reconstruction was demonstrated.

  12. TU-F-17A-09: Four-Dimensional Cone Beam CT Ventilation Imaging Can Detect Interfraction Lung Function Variations for Locally Advanced Lung Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Kipritidis, J; Keall, P [Radiation Physics Laboratory, University of Sydney, Sydney NSW 2006 Australia (Australia); Hugo, G; Weiss, E; Williamson, J [Department of Radiation Oncology, Virginia Commonwealth University, Richmond VA (United States)

    2014-06-15

    Purpose: Four-dimensional cone beam CT ventilation imaging (4D-CBCT VI) is a novel functional lung imaging modality requiring validation. We hypothesize that 4D-CBCT VI satisfies a necessary condition for validity: that intrafraction variations (e.g. due to poor 4D-CBCT image quality) are substantially different to interfraction variations (e.g. due to changes in underlying function). We perform the first comparison of intrafraction (pre/post fraction) and interfraction (week-to-week) 4D-CBCT VIs for locally advanced non small cell lung cancer (LA NSCLC) patients undergoing radiation therapy. Methods: A total of 215 4D-CBCT scans were acquired for 19 LA NSCLC patients over 4-6 weeks of radiation therapy, including 75 pairs of pre-/post-fraction scans on the same day. 4D-CBCT VIs were obtained by applying state-of-the-art, B-spline deformable image registration to obtain the Jacobian determinant of deformation between the end-exhale and end-inhale phases. All VIs were deformably registered to the corresponding first day scan, normalized between the 10th and 90th percentile values and cropped to the ipsilateral lung only. Intrafraction variations were assessed by computing the mean and standard deviation of voxel-wise differences between all same-day pairs of pre-/post-fraction VIs. Interfraction differences were computed between first-day VIs and treatment weeks 2, 4 and 6 for all 19 patients. We tested the hypothesis by comparing cumulative distribution functions (CDFs) of intrafraction and interfraction ventilation differences using two-sided Kolmogorov-Smirnov goodness-of-fit tests. Results: The (mean ± std. dev.) of intrafraction differences was (−0.007 ± 0.079). Interfraction differences for weeks 2, 4 and 6 were (−0.035 ± 0.103), (−0.006 ± 0.094) and (−0.019 ± 0.127) respectively. For week 2, the changes in CDFs for intrafraction and interfraction differences approached statistical significance (p=0.099). Conclusion: We have shown that 4D-CBCT VI

  13. FETAL ECHOCARDIOGRAPHY: A STUDY OF CLINICAL OUTCOME

    Directory of Open Access Journals (Sweden)

    Rajanish

    2014-01-01

    Full Text Available BACKGROUND : S tructural abnormalities of the heart and great vessels are fairly common congenital lab normalities with the incidenceof8 in 1000 live births. With the advent of real time scanners fetal cardia can atomy can be analyze d echocardiographically. The earlier diagnosis will make an impact on clinical management of fetus with congenital heart disease. It helps intimely triage and optimal management of specific congenital heart disease either structural , functional orarrhythmia . OBJECTIVES : This study was conducted to note the spectrum of congenital heart diseases detected on fetal echo in pregnant mothers referred with high risk for CHD sand to assess the outcome of prenatally detected congenital heart diseases. MATERIAL S AND METHODS : T he study is aprospective descriptive study conducted in a tertiary care pediatric hospital in Mumbai over period of one year . P regnant mothers were referred for fetal echo , where pregnancy was considered as high risk for CHDs due to maternal , fetalfactorsorabnormallevel 1 scan.Fetal echowas performed by a trained pediatric cardiologistat 18 to 20 week of gestation using HP sonos 2000 echocardiographicmachinewith3/3.5 Hz transducer. Cardiac lesionsandoutcome of pregnancy was noted by postnatal follow - up of patients. RESULTS : A total of 170 patients underwent fetal echo , 13 patients have not delivered and 48 were lost to follow - up. Fetal echo was normal in 130(76.4% and abnormalities were detected in 40(23.5%.Structural anomalies were seen in 24(14.1% , arrhythmia in 5(2.9% and functional abnormalities in 11(6.4%.On outcome analysis84 (77.1% arealive , IUD /terminationof pregnancyoccurred in 18(16.5% , neonatal death in 6 (5.5% , infant death in 1 (0.9%. CONCLUSIONS : All ranges of CHDs can be diagnosed by fetal echocardiography . O utcome of prenatally detected complex congenital heart disease is poor ; nonetheless earlier detection provides a n opportunity for early interventions and

  14. Modifications of Oxygen Saturation During Transesophageal Echocardiography.

    Science.gov (United States)

    Macor, Franco; Zottarel, Gabriella; Antonini-Canterin, Francesco; Mimo, Renata; Pavan, Daniela; Cervesato, Eugenio; Nicolosi, Gianluigi; Zanuttini, Domenico

    1997-05-01

    The present study was designed: (1) to establish the effects of transesophageal echocardiography (TEE) on arterial oxygen saturation (SAO(2)%); (2) to verify the possible clinical consequences of this phenomenon; and (3) to study the possibility of predicting modifications of SAO(2)% by clinical or hemodynamic variables or by specific factors related to the TEE procedure. We prospectively studied 116 unselected patients, aged 61 +/- 12 years, who underwent diagnostic TEE for various clinical indications. Thirty-seven patients had mitral valve disease, 19 aortic valve disease, 14 combined mitroaortic disease, 8 congenital heart disease, and 38 other cardiovascular diseases. Eight patients were affected by chronic obstructive pulmonary disease. Ninety-seven patients were sedated by 4 +/- 2 mg of diazepam IV SAO(2)% (5-min average) (Ohmeda Biox 3700 pulse oxymeter finger probe), heart rate (HR), and blood pressure (BP) were considered during baseline transthoracic examination, after pharmacological sedation but before the introduction of the probe, and finally during TEE. Neither clinical complications nor major arrhythmias were observed. Baseline SAO(2)%, HR and BP were, respectively, 93.6 +/- 3.3%, 76 +/- 14 beats/min, and 129 +/- 20/75 +/- 10 mmHg. Pharmacological sedation did not modify SAO(2)%, HR, and BP (P > 0.1). During TEE a small but significant reduction in SAO(2)% by an average of 1.2 +/- 3.2% was observed (P 0.1 for both systolic and diastolic). The changes of SAO(2)% and HR were not interrelated and were not related to the duration of the procedure and to any of the clinical and hemodynamic variables taken into consideration. TEE can induce a small but significant drop in SAO(2)% and a small increase in HR even without any clinical relevance. No clinical or hemodynamic variable or specific factors related to the TEE procedure were related to these changes.

  15. Digital tele-echocardiography: a look inside

    Directory of Open Access Journals (Sweden)

    Daniele Giansanti

    2009-12-01

    Full Text Available Digital tele-echocardiography (T-E has the potentiality to allow relevant change in health care organization. The purpose of the paper is to analyze the scientific development around the digital T-E to explore the successful applications and individuate the limits which hamper the routine introduction in the National Health Care System (NHCS. A literature review was carried out by searching for studies from 1988 to 2008. The studies have been investigated according to four crucial issues: a the employment of the digital T-E versus the traditional videotape registrations; b the evolution of the telecommunication network and T-E; c the quality assessment of the images after transmission; d the economical legal and social impact of the T-E. The analysis showed a generalized increased diffusion of the digital T-E thanks to the wonderful development of the information technology. This diffusion was sometimes also accompanied by investigation studies on the diagnostic accuracy and on cost-benefit analysis with special care to the economical and social impact. The study examined some points which need to be improved to allow a better introduction of the T-E in the NHCS as a routine exam. Among these two were the most important. The first was the lacking of an easy and automatic methodology for the image quality assessment alternative to the currently used methods which are highly complex, expensive and needing a long time to be applied. The second was the lacking of a properly designed methodology for the health technology assessment in T-E, the latter, as it is well known is a very complex and heterogeneus system embedding parts from telematics, bioengineering, and medical physics.

  16. Digital tele-echocardiography: a look inside.

    Science.gov (United States)

    Giansanti, Daniele; Morelli, Sandra

    2009-01-01

    Digital tele-echocardiography (T-E) has the potentiality to allow relevant change in health care organization. The purpose of the paper is to analyze the scientific development around the digital T-E to explore the successful applications and individuate the limits which hamper the routine introduction in the National Health Care System (NHCS). A literature review was carried out by searching for studies from 1988 to 2008. The studies have been investigated according to four crucial issues: a) the employment of the digital T-E versus the traditional videotape registrations; b) the evolution of the telecommunication network and T-E; c) the quality assessment of the images after transmission; d) the economical legal and social impact of the T-E. The analysis showed a generalized increased diffusion of the digital T-E thanks to the wonderful development of the information technology. This diffusion was sometimes also accompanied by investigation studies on the diagnostic accuracy and on cost-benefit analysis with special care to the economical and social impact. The study examined some points which need to be improved to allow a better introduction of the T-E in the NHCS as a routine exam. Among these two were the most important. The first was the lacking of an easy and automatic methodology for the image quality assessment alternative to the currently used methods which are highly complex, expensive and needing a long time to be applied. The second was the lacking of a properly designed methodology for the health technology assessment in T-E, the latter, as it is well known is a very complex and heterogeneous system embedding parts from telematics, bioengineering, and medical physics.

  17. SU-F-303-13: Initial Evaluation of Four Dimensional Diffusion- Weighted MRI (4D-DWI) and Its Effect On Apparent Diffusion Coefficient (ADC) Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y [Duke University Medical Physics Program (United States); Yin, F; Czito, B; Bashir, M; Palta, M; Cai, J [Duke University Medical Center, Durham, NC (United States); Zhong, X; Dale, B [Siemens Healthcare, Durham, NC (United States)

    2015-06-15

    Purpose: Diffusion-weighted imaging(DWI) has been shown to have superior tumor-to-tissue contrast for cancer detection.This study aims at developing and evaluating a four dimensional DWI(4D-DWI) technique using retrospective sorting method for imaging respiratory motion for radiotherapy planning,and evaluate its effect on Apparent Diffusion Coefficient(ADC) measurement. Materials/Methods: Image acquisition was performed by repeatedly imaging a volume of interest using a multi-slice single-shot 2D-DWI sequence in the axial planes and cine MRI(served as reference) using FIESTA sequence.Each 2D-DWI image were acquired in xyz-diffusion-directions with a high b-value(b=500s/mm2).The respiratory motion was simultaneously recorded using bellows.Retrospective sorting was applied in each direction to reconstruct 4D-DWI.The technique was evaluated using a computer simulated 4D-digital human phantom(XCAT),a motion phantom and a healthy volunteer under an IRB-approved study.Motion trajectories of regions-of-interests(ROI) were extracted from 4D-DWI and compared with reference.The mean motion trajectory amplitude differences(D) between the two was calculated.To quantitatively analyze the motion artifacts,XCAT were controlled to simulate regular motion and the motions of 10 liver cancer patients.4D-DWI,free-breathing DWI(FB- DWI) were reconstructed.Tumor volume difference(VD) of each phase of 4D-DWI and FB-DWI from the input static tumor were calculated.Furthermore, ADC was measured for each phase of 4D-DWI and FB-DWI data,and mean tumor ADC values(M-ADC) were calculated.Mean M-ADC over all 4D-DWI phases was compared with M-ADC calculated from FB-DWI. Results: 4D-DWI of XCAT,the motion phantom and the healthy volunteer demonstrated the respiratory motion clearly.ROI D values were 1.9mm,1.7mm and 2.0mm,respectively.For motion artifacts analysis,XCAT 4D-DWI images show much less motion artifacts compare to FB-DWI.Mean VD for 4D-WDI and FB-DWI were 8.5±1.4% and 108±15

  18. Estimation of circumferential fiber shortening velocity by echocardiography.

    Science.gov (United States)

    Ruschhaupt, D G; Sodt, P C; Hutcheon, N A; Arcilla, R A

    1983-07-01

    The M-mode and two-dimensional echocardiograms of 40 young patients were analyzed to compare the mean circumferential fiber shortening velocity (Vcf) of the left ventricle calculated separately by two methods. The mean circumferential fiber shortening velocity was derived from the M-mode echocardiogram as minor axis shortening/ejection time and derived from the two-dimensional echocardiogram as actual circumference change/ejection time. With computer assistance, circumference was determined from the short-axis two-dimensional echocardiographic images during end-diastole and end-systole. Good correlations were obtained between the left ventricular diameter derived by M-mode echocardiography and the vertical axis during end-diastole (r = 0.79) and end-systole (r = 0.88) derived by two-dimensional echocardiography. Likewise, high correlations were noted between diameter and circumference in end-diastole (r = 0.89) and end-systole (r = 0.88). However, comparison of Vcf obtained by M-mode echocardiography with that obtained by two-dimensional echocardiography showed only fair correlation (r = 0.68). Moreover, the diameter/circumference ratio determined in end-diastole and end-systole differed significantly (p less than 0.001), possibly owing to the change in geometry of the ventricular sector image during systole. Although Vcf derived by M-mode echocardiography is a useful index of left ventricular performance, it does not truly reflect the circumference change during systole.

  19. Application of echocardiography in resynchronization treatment of heart failure patients

    Institute of Scientific and Technical Information of China (English)

    DAI Hai-long; GUANG Xue-feng; XIAO Zhi-cheng; ZHANG Ming

    2012-01-01

    Objective To review the updated research progress about the application of echocardiography in resynchronization treatment of chronic heart failure patients.Data sources The data used in this review were from PubMed,published in English and using the key terms "heart failure","echocardiography" and "cardiac resynchronization therapy".Study selection Relevant articles were reviewed and selected to address the stated purpose.Results Increasing numbers of studies have suggested the importance of echocardiography in resynchronization treatment of chronic heart failure patients.Echocardiography can evaluate atrioventricular,inter- and intra-ventricular mechanical dyssynchrony before cardiac resynchronization therapy (CRT),as a guidance to assess the optimal left ventricular (LV) pacing location,optimize the atrioventricular and interventricular delays and predict response to CRT.Conclusions Echocardiography is both non invasive and easily repeatable,and plays a crucial role in appraisal of heart synchronism,instruction of actuator placement,optimization of the device procedure,and prediction of the response to CRT.Chin Med J 2012; 125(19):3548-3555

  20. What every radiologist should know about paediatric echocardiography

    Energy Technology Data Exchange (ETDEWEB)

    Sorantin, Erich, E-mail: erich.sorantin@medunigraz.at [Division of Pediatric Radiology, Department of Radiology, Medical University Graz, Auenbruggerplatz 34, A-8036 Graz (Austria); Heinzl, Bernd [Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine, Medical University Graz, Auenbruggerplatz 34, A-8036 Graz (Austria)

    2014-09-15

    Congenital heart defects (CHD) occur in less than one percent of all newborns. Echocardiography represents the imaging modality of choice for morphological and functional assessment. In childhood the different CHD types can be diagnosed trustfully and can be performed bedside. In the follow-up of CHD cross sectional imaging plays an important role and therefore it is essential for the radiologist to know the features, challenges and limitations of echocardiography. Within this review article a systematic approach for morphological and functional assessment of the heart will is given along with representative example images. In addition, typical echocardiographic findings in common CHD is presented. In older children, adolescents and grown-ups with CHD (GUCH) echocardiography suffers from limitations – partially due to skeletal deformations and lung emphysema. In particular right ventricular function assessment is not always possible by echocardiography. Therefore strengths and limitations of echocardiography will be discussed the role of cardiac magnetic resonance imaging (cMRI) and cardiac computed tomography (cCT) emphasized.

  1. Electrocardiography and echocardiography in athletic heart imagining

    Directory of Open Access Journals (Sweden)

    D Biały

    2003-03-01

    Full Text Available The aim of the study was evaluation of electrocardiographic and echocardiographic parameters in athletes. „Athletic heart” characteristics were compared with fit persons’ heart. 96 athletes participated in the study. Sportsmen were divided into: static (S, dynamic (D and composite (SD exercise groups and Polish (I, European (II, World (III champions. 30 students from Sport Academy formed the control group (K. Electrocardiographic and echocardiographic examination were performed in everyone. As regards the type of exercise, the end-systolic left ventricular (LV dimension was smaller in S in comparison with D and SD (28.9 vs 32.2 and 32.68 mm; P<0.05. LV mass was bigger in D in comparison with K (273.2 vs 218.6 g; P<0.05. Medium Pulmonary Artery Pressure (MPAP in S and SD was lower in respect to D and K (11.75; 11.08 vs 15.52; 17.43 mm Hg; P<0.05. We observed lower heart rate in D, SD in comparison with K (58.64; 60.54 vs 68.8; P<0.05, bigger R wave amplitude in V5 (RV5 (21.65; 23.5 vs 15.03 mm; P<0.05 and V6 (RV6 (23.5 vs 15.3 mm; P<0.05 in group S in respect to K. LV mass was bigger in III than in K (261.3 vs 218.6 g; P<0.05. MPAP was lower in I and II in comparison with K (11.42; 13.13 vs 17.43 mmHg; P<0.05. HR was lower in categories I, II than in K (61.32; 60.13 vs 68.8; P<0.05, RV5 was bigger in I in comparison with K (19.5 vs 15.03 mm; P<0.05. The electrocardiography and echocardiography proves to find some significant differences between athletic and fit persons’ heart especially as concerns MPAP, RV5, RV6 values.

  2. Unified treatment of one-range addition theorems for integer and non-integer n-STO, -GTO and-generalized exponential type orbitals with hyperbolic cosine in position, momentum and four-dimensional spaces

    Institute of Scientific and Technical Information of China (English)

    I. I. Guseinov

    2012-01-01

    Simpler formulas are derived for one-range addition theorems for the integer and noninteger n generalized exponential type orbitals,momentum space orbitals,and hyperspherical harmonics with hyperbolic cosine (GETO HC,GMSO HC,and GHSH HC) in position,momentum and four-dimensional spaces,respectively.The final results are expressed in terms of one-range addition theorems of complete orthonormal sets of ψα-exponential type orbitals,(φ)α-momentum space orbitals and zα-hyperspherical harmonics.We notice that the one-range addition theorems for integer and noninteger n-Slater type orbitals and Gaussian type orbitals in position,momentum and four dimensional spaces are special cases of GETO HC,GMSO HC,and GHSH HC.The theorems presented can be useful in the accurate study of the electronic structure of atomic and molecular systems.

  3. The Clinical Value of Four-dimensional Ultrasound in Pregnancy Diagnosis of Cleft Lip and Palate%分析四维超声在中孕期胎儿唇腭裂诊断中的临床价值

    Institute of Scientific and Technical Information of China (English)

    李妍钰

    2016-01-01

    Objective To assess the prenatal diagnosis of fetal cleft lip and palate in promoting the clinical effectiveness of four-dimensional ultrasound solutions. Methods A total of 17 958 cases of fetus during pregnancy were randomly selected from April 2014 to December 2015, the late confirms 40 cases of fetal cleft lip and palate, all take the four-dimensional ultrasound, observe all the fetal diagnosis. Results In the fetus, the four dimensional ultrasonic testing found that fetal cleft lip and palate, a total of 39 cases, the coincidence rate of 97.50% (P>0.05). Conclusion In the prenatal diagnosis of fetal cleft lip and palate, promote the four-dimensional ultrasound has the feasibility, the operation is convenient, is worth promoting.%目的:评定中孕期胎儿唇腭裂诊断中推行四维超声方案的临床有效性。方法随机选择我院2014年4月~2015年12月接收的中孕期胎儿共17958例,后期证实唇腭裂胎儿40例,均接受四维超声方案,观察所有入选胎儿诊断结果。结果入选的胎儿中,四维超声检测发现唇腭裂胎儿共39例,其符合率97.50%,与后期追踪结果对比差异无统计学意义(P >0.05)。结论在中孕期胎儿唇腭裂诊断中,推行四维超声方案具有可行性,操作便捷。

  4. 四维超声检查对胎儿唇腭裂的诊断价值%Four dimensional ultrasound in diagnosis of fetal cleft lip and cleft palate

    Institute of Scientific and Technical Information of China (English)

    莫慧端; 吴忠明; 蔡碧琼; 曾思惠

    2015-01-01

    Objective To investigate the value of four-dimensional color Doppler in diagnosis of fetal cleft lip and cleft palate.Methods The four-dimensional color Doppler for 24-28weeks of pregnancy in 13 548 pregnant women by prenatal ultrasound.Results Found 21 cases of fetal cleft lip and cleft palate,2 cases were missed,were confirmed.Conclusion Four dimensional color Doppler dynamic continuous observation of the fetal activity,plays an important role in diagnosis of fetal cleft lip and cleft palate and typing,which can increase the detection rate of fetal cleft lip and palate.%目的 探讨四维彩色多普勒诊断胎儿唇腭裂畸形的价值.方法 采用四维彩色多普勒对孕24~28周13 548例孕妇进行产前超声检查.结果 发现唇腭裂畸形胎儿21例,漏诊2例,均得以证实.结论 四维彩色多普勒动态连续观察胎儿的活动,对胎儿唇腭裂畸形的诊断及分型具有重要意义,能提高胎儿唇腭裂的检出率.

  5. Technology update: intracardiac echocardiography – a review of the literature

    Directory of Open Access Journals (Sweden)

    Vitulano N

    2015-05-01

    Full Text Available Nicola Vitulano, Vincenzo Pazzano, Gemma Pelargonio, Maria Lucia Narducci Institute of Cardiology, Department of Cardiovascular Sciences, Catholic University of the Sacred Heart, Rome, Italy Abstract: The development of new imaging tools helps in better investigation of cardiac structures and function by showing detailed images during interventional procedures. Intracardiac echocardiography plays a pivotal role as an intraoperative real-time imaging tool during invasive cardiac procedures. Initially, this echocardiographic technique was particularly useful when transthoracic image quality was insufficient and to avoid general anesthesia for transesophageal imaging. Nowadays, intracardiac echocardiography is routinely used in several cardiac invasive laboratories to support several types of procedures, such as extraction and implantation of cardiac devices, electrophysiological mapping, ablation, and endomyocardial biopsies. This review gives an overview of the basic principles of intracardiac echocardiography and examines its applications in the different settings of invasive cardiology. Keywords: ICE, cardiovascular imaging, electrophysiology, invasive cardiology

  6. Assessment of right ventricular systolic function by tissue Doppler echocardiography

    DEFF Research Database (Denmark)

    Kjærgaard, Jesper

    2012-01-01

    myocardial velocities, but no changes in SR, strain or isovolumic acceleration could be observed [II and III]. Tissue Doppler echocardiography of the RV free wall in non-massive pulmonary embolism quantifies degree of RV dysfunction, and supports the existence of the McConnell sign of mid-ventricular RV...... structure including significant dilatation, but is well tolerated with only mild reduction in measures of global RV systolic function as estimated by 2D echocardiography in an experimental animal model. Regional RV myocardial function is also only mildly reduced. Also no differences in global or regional RV......This thesis summarizes a series of studies performed in order to assess the clinical usefulness of a novel echocardiographic technology that allows non-invasive assessment of regional right ventricular myocardial velocities and deformation: tissue Doppler echocardiography. While the technology...

  7. Recommendations for fetal echocardiography in twin pregnancy in 2016

    Directory of Open Access Journals (Sweden)

    Leszczyńska Katarzyna

    2016-01-01

    Full Text Available Progress in the fields of fetal cardiology and fetal surgery have been seen not only in singleton pregnancies but also in multiple pregnancies. Proper interpretation of prenatal echocardiography is critical to clinical decision making, family counseling and perinatal management for obstetricians, maternal fetal medicine specialists, neonatologists and pediatric cardiologists. Fetal echocardiography is one of the most challenging and time-consuming prenatal examinations to perform, especially in multiple gestations. Performing just the basic fetal exam in twin gestations may take an hour or more. Thus, it is not practical to perform this exam in all cases of multiple gestations. Therefore our review and recommendations are related to fetal echocardiography in twin gestation.

  8. The Optimum Level of Sevoflurane in Pediatric Echocardiography.

    Science.gov (United States)

    Conghai, Fan; Fengchao, Zhang; Chengjing, Shan; Cheng, Wen; Yunji, Wang; Xiaobo, Li

    2015-11-01

    Sevoflurane is shown to be safe and effective in pediatric echocardiography. This study explores the optimum level in pediatric echocardiography. One hundred and twenty children, with an age range of 35 days-3 years, were included in this study. The children with severe cyanotic congenital heart disease or severe pneumonia, which was Grade I or II according to the American College of Physicians Guideline Grading, were excluded. All children received the anesthesia with sevoflurane. The inhalation anesthesia level decreased from 2.5 to 1.0 %, with a decrement of 0.5 %. The induction time (T0), echocardiography time (T1), and time to awakening (T2) in each child were recorded, and the changes in the blood pressure, heart rate, breath, and oxygen saturation in each child were also monitored. The Ramsay scale scoring during anesthesia and the case number of failure in echocardiography in each group were also recorded. When the level of sevoflurane inhalation was maintained at 1.0 %, the childrens' scores were low, including 8 incompliant children, and p sevoflurane inhalation level increased. When the sevoflurane inhalation increased to 1.5 %, the children could sleep with stable blood pressure, and no dysphoria occurred during the echocardiography. When the sevoflurane inhalation level increased to 2.5 %, the Ramsay scores did not increase. However, the T2 significantly increased (p blood pressure and heart rate in each group did not change significantly. With the premise of safety and efficacy in children, the optimum level of sevoflurane in pediatric echocardiography was 1.5-2.0 %.

  9. Acute right ventricular dysfunction: real-time management with echocardiography.

    Science.gov (United States)

    Krishnan, Sundar; Schmidt, Gregory A

    2015-03-01

    In critically ill patients, the right ventricle is susceptible to dysfunction due to increased afterload, decreased contractility, or alterations in preload. With the increased use of point-of-care ultrasonography and a decline in the use of pulmonary artery catheters, echocardiography can be the ideal tool for evaluation and to guide hemodynamic and respiratory therapy. We review the epidemiology of right ventricular failure in critically ill patients; echocardiographic parameters for evaluating the right ventricle; and the impact of mechanical ventilation, fluid therapy, and vasoactive infusions on the right ventricle. Finally, we summarize the principles of management in the context of right ventricular dysfunction and provide recommendations for echocardiography-guided management.

  10. Stress echocardiography in valvular heart disease: a current appraisal.

    Science.gov (United States)

    Naji, Peyman; Patel, Krishna; Griffin, Brian P; Desai, Milind Y

    2015-03-01

    Stress echocardiography is increasingly used in the management of patients with valvular heart disease and can aid in evaluation, risk stratification and clinical decision making in these patients. Evaluation of symptoms, exercise capacity and changes in blood pressure can be done during the exercise portion of the test, whereas echocardiographic portion can reveal changes in severity of disease, pulmonary artery pressure and left ventricular function in response to exercise. These parameters, which are not available at rest, can have diagnostic and prognostic importance. In this article, we will review the indications and diagnostic implications, prognostic implications, and clinical impact of stress echocardiography in decision making and management of patients with valvular heart disease.

  11. Role of Speckle Tracking Echocardiography in Dilated Cardiomyopathy: A Review

    Science.gov (United States)

    Virk, Hafeez Ul Hasan; Khalid, Muhammad; Rahman, Zia; Sitwala, Puja; Schoondyke, Jeffrey; Al-Balbissi, Kais

    2017-01-01

    Dilated cardiomyopathy (DCM) is an important cause of the heart failure. Timely diagnosis and optimal management decrease morbidity and mortality in heart failure patients. Although transthoracic echocardiography is used as the diagnostic test of choice in these patients, new modalities like speckle tracking echocardiography (STE) have promising results in diagnosing these patients in the earlier course of the disease. Advancements in cardiac imaging are expected as more clinical studies on the role of STE in different cardiac diseases that emerge. In this review article, we will discuss the basics of STE and its role in diagnosing DCM. PMID:28744419

  12. 基于四维CT的肺体积及呼吸运动分析%Four-dimensional CT in the study of lung volume and respiratory movement

    Institute of Scientific and Technical Information of China (English)

    孙宗文; 黄晓延; 包勇; 张黎; 黄劭敏; 樊卫; 陈明; 邓小武

    2008-01-01

    Objective To evaluate the respiratory movement of the both lungs with four-dimensional CT(4DCT), and determine the optimal respiratory phase series CT images for radiation dose calculation. Methods From November 2005 to November 2006,thirty patients with lung cancer who received 4DCT scan were enrolled,including 15 left and 15 right lung cancer cases,25 men and 5 women. The media age was 55 (35-78) years old. After 4DCT scanning, the image was treated with Advantage 4D workstation,and then transmitted into Pinnacle station( Adac 7.4). The both lungs were automatically outlined using Pinnacle station with CT recognition value of-900 to-200 Hu. Then-the same physician examined the unreasonable parts and revised them. After the delineation was completed,the volume of 10 respiratory phases of lung was obtained. Results The average respiratory phase in inspiratory and expiratory phases was 78.87%±2.71% and 26.32%±3.17% in the tumor located lung,77.55%±2.81% and 24.73%±2.55% in the healthy lung. The maximum and minimum mean volume was 106.48%±3.00% and 94.23%±2.78% in the tumor located lung,107.47%±2.43% and 93.65%±2.32% in the healthy lung. The volume at the end of inspiratory and expiratory was 106.43%±3.07% and 94.63%±2.71% in the tumor located lung, 107.37%±4.62% and 93.98%±2.34% in the healthy lung. Conclusions The series CT images scan on 20% ,30% and 80% respiratory phases are reasonable for radiation dose calculation. The maximum and minimum average lung volumes are almost equal to those at the end of inspiratory and expiratory.%目的 应用四维CT(4DCT)评价肺癌患者肺的运动,并初步选择适合进行剂量计算的呼吸时相.方法 选择30例在中山大学肿瘤医院接受4DCT扫描的肺癌患者,左、右肺患者均为15例;男25例、女5例;中位年龄55岁(35~78岁).CT扫描完成后所得到的影像资料经4D软件处理后传至Pinnacle工作站,应用该软件自动勾画功能勾画双侧肺轮廓,自动怪勾画

  13. 四维彩超检查在胎儿先心病诊断中的临床应用%Clinical Application of Four-dimensional Color Doppler Ultrasonography in the Diagnosis of Fetal Congenital Heart Disease

    Institute of Scientific and Technical Information of China (English)

    谢广平; 贾立娟; 杜学谦

    2016-01-01

    ABSTRACT:Objective To analyze the application value of four-dimensional color Doppler ultrasonography in the diagnosis of fetal congenital heart disease, and to provide a reliable reference for clinical practice. Methods The research subjects in this study were 90 cases of fetus,whose gestational age were 25 to 40 weeks. All subjects were examined by four-dimensional color Doppler ultrasound. The results of four-dimensional color Doppler ultrasound examination of these studies subjects were retrospective analyzed,such as fetal heart rate, the four chamber view, the lfow of the chamber, etc..At the same time, the results of follow-up were retrospectively analyzed. The follow-up results and contrast the four-dimensional color Doppler ultrasound examination results were compared.The accuracy of the four-dimensional color Doppler ultrasound examination for diagnosis of fetal congenital heart disease were calculated ,in order to investigate the application value of four-dimensional color Doppler ultrasonography in the diagnosis of fetal congenital heart disease. Results In the study, 6 cases were diagnosed as congenital heart disease by four-dimensional color Doppler ultrasonography. Follow up results showed that 8 cases were eventually diagnosed as congenital heart disease in the study. By comparing the four-dimensional color Doppler ultrasound examination results and follow-up results, the diagnosis rate of four-dimensional color Doppler ultrasound examination was 75%, 1 cases was misdiagnosis, 1 cases was missed diagnosis. Conclusion Prenatal four-dimensional color Doppler ultrasound examination can improve the diagnostic rate of fetal congenital heart disease, and provide a reliable reference for the early intervention of congenital heart disease. Four-dimensional color Doppler ultrasound examination can be widely used in the diagnosis of fetal congenital heart disease, can provide referenc e for the early diagnosis and intervention of congenital heart disease

  14. Exercise echocardiography in asymptomatic survivors of childhood cancer treated with anthracyclines

    DEFF Research Database (Denmark)

    Sieswerda, Elske; Kremer, Leontien C M; Vidmar, Suzanna

    2010-01-01

    BACKGROUND: Exercise echocardiography reveals abnormalities in asymptomatic childhood cancer survivors who previously have been treated with anthracyclines. We determined the added value of monitoring childhood cancer survivors with exercise echocardiography compared to monitoring with resting ec...

  15. Association of heart failure hospitalizations with combined electrocardiography and echocardiography criteria for left ventricular hypertrophy

    DEFF Research Database (Denmark)

    Gerdts, Eva; Okin, Peter M; Boman, Kurt

    2012-01-01

    The value of performing echocardiography in hypertensive patients with electrocardiographic left ventricular hypertrophy (LVH) is uncertain.......The value of performing echocardiography in hypertensive patients with electrocardiographic left ventricular hypertrophy (LVH) is uncertain....

  16. The Role of Focused Echocardiography in Pediatric Intensive Care: A Critical Appraisal

    Directory of Open Access Journals (Sweden)

    Heloisa Amaral Gaspar

    2015-01-01

    Full Text Available Echocardiography is a key tool for hemodynamic assessment in Intensive Care Units (ICU. Focused echocardiography performed by nonspecialist physicians has a limited scope, and the most relevant parameters assessed by focused echocardiography in Pediatric ICU are left ventricular systolic function, fluid responsiveness, cardiac tamponade and pulmonary hypertension. Proper ability building of pediatric emergency care physicians and intensivists to perform focused echocardiography is feasible and provides improved care of severely ill children and thus should be encouraged.

  17. Exercise stress echocardiography in patients with valvular heart disease.

    Science.gov (United States)

    Sharma, Vishal; Newby, David E; Stewart, Ralph A H; Lee, Mildred; Gabriel, Ruvin; Van Pelt, Niels; Kerr, Andrew J

    2015-09-01

    Stress echocardiography is recommended for the assessment of asymptomatic patients with severe valvular heart disease (VHD) when there is discrepancy between symptoms and resting markers of severity. The aim of this study is to determine the prognostic value of exercise stress echocardiography in patients with common valve lesions. One hundred and fifteen patients with VHD (aortic stenosis (n=28); aortic regurgitation (n=35); mitral regurgitation, (n=26); mitral stenosis (n=26)), and age- and sex-matched controls (n=39) with normal ejection fraction underwent exercise stress echocardiography. The primary endpoint was a composite of death or hospitalization for heart failure. Asymptomatic VHD patients had lower exercise capacity than controls and 37% of patients achieved 60 mmHg) was associated with an increased risk of death or hospital admission (14% vs 1%, P<0.0001). The assessment of contractile reserve did not offer additional predictive value. In conclusion, an abnormal stress echocardiogram is associated with death and hospitalization with heart failure at 2 years. Stress echocardiography should be considered as part of the routine follow-up of all asymptomatic patients with VHD.

  18. Stress-echocardiography in idiopathic dilated cardiomyopathy: instructions for use

    Directory of Open Access Journals (Sweden)

    Neskovic Aleksandar N

    2005-02-01

    Full Text Available Abstract A number of studies have suggested that stress-echocardiography may be used for prognostic stratification in patients with idiopathic dilated cardiomyopathy. There is no consensus on which protocol or which measurements of left ventricular contractile reserve to use. The most frequently used protocol is low-dose dobutamine stress-echocardiography, and most commonly used measures of left ventricular systolic performance are ejection fraction, wall motion score index and cardiac power output. Stress-echocardiography has been shown to predict improvement in cardiac function in patients with recently diagnosed dilated cardiomyopathy, as well as to predict which patients will benefit from the treatment with beta-blockers. Most importantly, stress-echocardiography can identify patients with worse prognosis in terms of cardiac death and need for transplantation. Additionally, contractile reserve is closely correlated with maximal oxygen consumption and can even be used for further stratification in patients with maximal oxygen consumption between 10 and 14 ml/kg/min. Future studies are needed for head-to-head comparison of various protocols in an attempt to make standardization in the assessment of patients with dilated cardiomyopathy.

  19. Differential Diagnosis of Cardiac Malposition by Fetal Echocardiography

    Institute of Scientific and Technical Information of China (English)

    Ying WU; Feng TAO; Tao LIU; Ling ZANG; Shi-long LIU

    2009-01-01

    Objectives To explore the method and operating skill of fetal echocardiography in diagnosing cardiac malposition. Methods 91 consecutive fetuses were studied (control: 50 cases, cardiac malposition : 41 cases) between 2003 and 2008. The position of fetal heart was evaluated according to the fetal posture and the visceral situs by fetal routine scan-ning. The detailed echocardiography should be performed in the differential diagnosis of cardiac lesions when the heart was found to be abnormal position. Results In the control group, all fetuses were levocardia. 39 cases of cardiac mal-positions were detected by fetal echocardiography, included 25 fetuses with dextrocardia, 6 mesocard, 5 with levover-sion of heart, 3 common heart of conjoined twins and 2 extrathorax heart. Two of dextroversion were missed by fetal routine scanning, but found by autopsy or operation after birth. Conclusions When the abnormal visceral situs was found by fetal routine scanning, there is exceedingly high incidence of cardiac malpositions. Proficiently operating skill of fetal echocardiography is helpful to detect abnormal fetal cardiac position.

  20. Low-dose adenosine stress echocardiography: Detection of myocardial viability

    Directory of Open Access Journals (Sweden)

    Nedeljkovic Milan

    2003-06-01

    Full Text Available Abstract Objective The aim of this study was to evaluate the diagnostic potential of low-dose adenosine stress echocardiography in detection of myocardial viability. Background Vasodilation through low dose dipyridamole infusion may recruit contractile reserve by increasing coronary flow or by increasing levels of endogenous adenosine. Methods Forty-three patients with resting dyssynergy, due to previous myocardial infarction, underwent low-dose adenosine (80, 100, 110 mcg/kg/min in 3 minutes intervals echocardiography test. Gold standard for myocardial viability was improvement in systolic thickening of dyssinergic segments of ≥ 1 grade at follow-up. Coronary angiography was done in 41 pts. Twenty-seven patients were revascularized and 16 were medically treated. Echocardiographic follow up data (12 ± 2 months were available in 24 revascularized patients. Results Wall motion score index improved from rest 1.55 ± 0.30 to 1.33 ± 0.26 at low-dose adenosine (p Conclusion Low-dose adenosine stress echocardiography test has high diagnostic potential for detection of myocardial viability in the group of patients with left ventricle dysfunction due to previous myocardial infarction. Low dose adenosine stress echocardiography may be adequate alternative to low-dose dobutamine test for evaluation of myocardial viability.

  1. Update of the echocardiography core syllabus of the European Association of Cardiovascular Imaging (EACVI).

    Science.gov (United States)

    Cosyns, Bernard; Garbi, Madalina; Separovic, Jadranka; Pasquet, Agnes; Lancellotti, Patrizio

    2013-09-01

    The update of the Echocardiography Core Syllabus of European Association of Cardiovascular Imaging (EACVI) is now available online. The Echocardiography Core Syllabus enumerates the elements of knowledge to be taught, represents a framework for the development of local training curricula and provides expected learning outcomes to the echocardiography learner.

  2. Computer-based training in two-dimensional echocardiography using an echocardiography simulator.

    Science.gov (United States)

    Weidenbach, Michael; Wild, Florentine; Scheer, Kathrin; Muth, Gerhard; Kreutter, Stefan; Grunst, Gernoth; Berlage, Thomas; Schneider, Peter

    2005-04-01

    Two-dimensional (2D) echocardiography is a user-dependent technique that poses some inherent problems to the beginner. The first problem for beginners is spatial orientation, especially the orientation of the scan plane in reference to the 3-dimensional (3D) geometry of the heart. The second problem for beginners is steering of the ultrasound probe. We have designed a simulator to teach these skills. On a computer screen a side-by-side presentation of a 3D virtual reality scene on the right side and a 2D echocardiographic view on the left side is given. The virtual scene consists of a 3D heart and an ultrasound probe with scan plane. The 2D echocardiographic image is calculated from 3D echocardiographic data sets that are registered with the heart model to achieve spatial and temporal congruency. The displayed 2D echocardiographic image is defined and controlled by the orientation of the virtual scan plane. To teach hand-eye coordination we equipped a dummy transducer with a 3D tracking system and placed it on a dummy torso. We have evaluated the usability of the simulator in an introductory course for final-year medical students. The simulator was graded realistic and easy to use. According to a subjective self-assessment by a standardized questionnaire the aforementioned skills were imparted effectively.

  3. Low-dose adenosine stress echocardiography: Detection of myocardial viability

    Science.gov (United States)

    Djordjevic-Dikic, Ana; Ostojic, Miodrag; Beleslin, Branko; Nedeljkovic, Ivana; Stepanovic, Jelena; Stojkovic, Sinisa; Petrasinovic, Zorica; Nedeljkovic, Milan; Saponjski, Jovica; Giga, Vojislav

    2003-01-01

    Objective The aim of this study was to evaluate the diagnostic potential of low-dose adenosine stress echocardiography in detection of myocardial viability. Background Vasodilation through low dose dipyridamole infusion may recruit contractile reserve by increasing coronary flow or by increasing levels of endogenous adenosine. Methods Forty-three patients with resting dyssynergy, due to previous myocardial infarction, underwent low-dose adenosine (80, 100, 110 mcg/kg/min in 3 minutes intervals) echocardiography test. Gold standard for myocardial viability was improvement in systolic thickening of dyssinergic segments of ≥ 1 grade at follow-up. Coronary angiography was done in 41 pts. Twenty-seven patients were revascularized and 16 were medically treated. Echocardiographic follow up data (12 ± 2 months) were available in 24 revascularized patients. Results Wall motion score index improved from rest 1.55 ± 0.30 to 1.33 ± 0.26 at low-dose adenosine (p < 0.001). Of the 257 segments with baseline dyssynergy, adenosine echocardiography identified 122 segments as positive for viability, and 135 as necrotic since no improvement of systolic thickening was observed. Follow-up wall motion score index was 1.31 ± 0.30 (p < 0.001 vs. rest). The sensitivity of adenosine echo test for identification of viable segments was 87%, while specificity was 95%, and diagnostic accuracy 90%. Positive and negative predictive values were 97% and 80%, respectively. Conclusion Low-dose adenosine stress echocardiography test has high diagnostic potential for detection of myocardial viability in the group of patients with left ventricle dysfunction due to previous myocardial infarction. Low dose adenosine stress echocardiography may be adequate alternative to low-dose dobutamine test for evaluation of myocardial viability. PMID:12812523

  4. Can simulation help to answer the demand for echocardiography education?

    Science.gov (United States)

    Clau-Terré, Fernando; Sharma, Vivek; Cholley, Bernard; Gonzalez-Alujas, Teresa; Galiñanes, Manuel; Evangelista, Artur; Fletcher, Nick

    2014-01-01

    There has been a recent explosion of education and training in echocardiography in the specialties of anesthesiology and critical care. These devices, by their impact on clinical management, are changing the way surgery is performed and critical care is delivered. A number of international bodies have made recommendations for training and developed examinations and accreditations.The challenge to medical educators in this area is to deliver the training needed to achieve competence into already over-stretched curricula.The authors found an apparent increase in the use of simulators, with proven efficacy in improving technical skills and knowledge. There is still an absence of evidence on how it should be included in training programs and in the accreditation of certain levels.There is a conviction that this form of simulation can enhance and accelerate the understanding and practice of echocardiography by the anesthesiologist and intensivists, particularly at the beginning of the learning curve.

  5. Entropy-based straight kernel filter for echocardiography image denoising.

    Science.gov (United States)

    Rajalaxmi, S; Nirmala, S

    2014-10-01

    A new filter has been proposed with the aim of eliminating speckle noise from 2D echocardiography images. This speckle noise has to be eliminated to avoid the pseudo prediction of the underlying anatomical facts. The proposed filter uses entropy parameter to measure the disorganized occurrence of noise pixel in each row and column and to increase the image visibility. Straight kernels with 3 pixels each are chosen for the filtering process, and the filter is slided over the image to eliminate speckle. The peak signal-to-noise ratio (PSNR) is obtained in the range of 147 dB, and the root mean square error (RMSE) is very low of approximately 0.15. The proposed filter is implemented on 36 echocardiography images, and the filter has the competence to illuminate the actual anatomical facts without degrading the edges.

  6. Role of echocardiography in the treatment of cardiac tamponade.

    Science.gov (United States)

    Chandraratna, P A N; Mohar, Dilbahar S; Sidarous, Peter F

    2014-08-01

    Accumulation of fluid within the pericardial sac results in elevation of intrapericardial pressure with consequent cardiac compression or tamponade. Cardiac tamponade is a life-threatening condition which requires urgent evacuation of pericardial effusion (PE). Current pericardial evacuation techniques and approaches are varied. Echocardiography provides valuable insights into identifying patients who are suitable candidates and further facilitates pericardiocentesis by improving guidance techniques. Several previous publications have provided excellent reviews of the pathophysiology of cardiac tamponade. We review the clinical presentation and role of echocardiography for diagnosis of tamponade. We focus on medical and surgical approaches for the removal of PE. Moreover, as the clinical and hemodynamic consequences of PE depend on the volume and the rate of accumulation of PE, we review the various scenarios of "small" PE resulting in cardiac tamponade.

  7. The Interplay between Fasting Glucose, Echocardiography, and Biomarkers

    DEFF Research Database (Denmark)

    Pareek, Manan

    2017-01-01

    preventive setting, remains incomplete. Phenotypical heterogeneity may be even greater among subjects with hyperglycemic conditions, i.e., prediabetes and diabetes, which is worrisome, given the dramatic global rise in mean fasting glucose levels, and the strong association with adverse cardiovascular...... subclinical changes to manifest disease include echocardiography and circulating biomarkers. Objectives 1) To examine whether greater fasting plasma glucose (FPG) levels were associated with left ventricular mass (LVM), geometric pattern, diastolic function, and concentrations of N-terminal prohormone...... from the three categories defined by baseline FPG, i.e., normal fasting glucose, impaired fasting glucose, and diabetes, including use of anti-diabetic medication. Blood samples for cardiovascular biomarker assessments were drawn at the time of echocardiography and kept frozen until analysis. Outcome...

  8. Portopulmonary hypertension: Improved detection using CT and echocardiography in combination

    Energy Technology Data Exchange (ETDEWEB)

    Devaraj, Anand [Royal Brompton and Harefield NHS Foundation Trust, Department of Radiology, London (United Kingdom); Loveridge, Robert; Bernal, William; Willars, Christopher; Wendon, Julia A.; Auzinger, Georg [King' s College Hospital NHS Foundation Trust, The Institute of Liver Studies, King' s Health Partners, King' s College London, London (United Kingdom); Bosanac, Diana; Stefanidis, Konstantinos; Desai, Sujal R. [King' s College Hospital NHS Foundation Trust, Department of Radiology, King' s Health Partners, King' s College London, London (United Kingdom)

    2014-10-15

    To establish the relationship between CT signs of pulmonary hypertension and mean pulmonary artery pressure (mPAP) in patients with liver disease, and to determine the additive value of CT in the detection of portopulmonary hypertension in combination with transthoracic echocardiography. Forty-nine patients referred for liver transplantation were retrospectively reviewed. Measured CT signs included the main pulmonary artery/ascending aorta diameter ratio (PA/AA{sub meas}) and the mean left and right main PA diameter (RLPA{sub meas}). Enlargement of the pulmonary artery compared to the ascending aorta was also assessed visually (PA/AA{sub vis}). CT measurements were correlated with right-sided heart catheter-derived mPAP. The ability of PA/AA{sub vis} combined with echocardiogram-derived right ventricular systolic pressure (RVSP) to detect portopulmonary hypertension was tested with ROC analysis. There were moderate correlations between mPAP and both PA/AA{sub meas} and RLPA{sub meas} (r{sub s} = 0.41 and r{sub s} = 0.42, respectively; p < 0.005). Compared to transthoracic echocardiography alone (AUC = 0.59, p = 0.23), a diagnostic algorithm incorporating PA/AA{sub vis} and transthoracic echocardiography-derived RVSP improved the detection of portopulmonary hypertension (AUC = 0.8, p < 0.0001). CT contributes to the non-invasive detection of portopulmonary hypertension when used in a diagnostic algorithm with transthoracic echocardiography. CT may have a role in the pre-liver transplantation triage of patients with portopulmonary hypertension for right-sided heart catheterisation. (orig.)

  9. Pacemaker optimization guided by echocardiography in cardiac resynchronization therapy

    Directory of Open Access Journals (Sweden)

    Trifunović Danijela

    2009-01-01

    Full Text Available Introduction. Cardiac resynchronization therapy (CRT or biventricular pacing is a contemporary treatment in the management of advanced heart failure. Echocardiography plays an evolving and important role in patient selection for CRT, follow-up of acute and chronic CRT effects and optimization of device settings after biventricular pacemaker implantation. In this paper we illustrate usefulness of echocardiography for successful AV and VV timing optimization in patients with CRT. A review of up-to-date literature concerning rationale for AV and VV delay optimization, echocardiographic protocols and current recommendations for AV and VV optimization after CRT are also presented. Outline of Cases. The first case is of successful AV delay optimization guided by echocardiography in a patient with dilated cardiomyopathy treated with CRT is presented. Pulsed blood flow Doppler was used to detect mitral inflow while programming different duration of AV delay. The AV delay with optimal transmittal flow was established. The optimal mitral flow was the one with clearly defined E and A waves and maximal velocity time integral (VTI of the mitral flow. Improvement in clinical status and reverse left ventricle remodelling with improvement of ejection fraction was registered in our patient after a month. The second case presents a patient with heart failure caused by dilated cardiomyopathy; six months after CRT implantation the patient was still NYHA class III and with a significantly depressed left ventricular ejection fraction. Optimization of VV interval guided by echocardiography was undertaken measuring VTI of the left ventricular outflow tract (LVOT during programming of different VV intervals. The optimal VV interval was determined using a maximal LVOT VTI. A month after VV optimization our patient showed improvement in LV ejection fraction. Conclusion. Optimal management of patients treated with CRT integrate both clinical and echocardiographic follow

  10. How standard transesophageal echocardiography views change with dextrocardia.

    Science.gov (United States)

    Raut, Monish S; Maheshwari, Arun; Shad, Sujay; Rachna, G

    2013-01-01

    Dextrocardia with situs inversus is a rare condition. Situs inversus with dextrocardia is also called as "situs inversus totalis". Transesophageal echocardiography (TEE) views in dextrocardia patient are not discussed in the literature. The cardiac position and the cardiac chambers are mirror image of the normal anatomy. Because of this positional change, certain TEE probe and multiplane angle manipulations are required to obtain the recommended views.

  11. Usefulness of echocardiography in preparticipation screening of competitive athletes.

    Science.gov (United States)

    Grazioli, Gonzalo; Merino, Beatriz; Montserrat, Silvia; Vidal, Bàrbara; Azqueta, Manel; Pare, Carles; Sarquella-Brugada, Georgia; Yangüas, Xavier; Pi, Ramon; Til, Lluis; Escoda, Jaume; Brugada, Josep; Sitges, Marta

    2014-09-01

    Despite the established diagnostic value of the electrocardiogram in preparticipation screening of athletes, some cardiac structural changes can be missed, particularly in early disease stages. The aim of this study was to evaluate the prevalence of cardiac structural changes via the systematic use of echocardiography in preparticipation screening of competitive athletes. Professional athletes or participants in a competitive athletic program underwent a screening that included family and personal medical history, physical examination, electrocardiography, exercise testing, and Doppler echocardiography. A total of 2688 athletes (67% men; mean age [standard deviation], 21 [10] years) were included. Most of the echocardiographic evaluations (92.5%) were normal and only 203 (7.5%) showed changes; the most frequent change was left ventricular hypertrophy, seen in 50 athletes (1.8%). Cessation of athletic activity was indicated in 4 athletes (0.14%): 2 for hypertrophic cardiomyopathy (electrocardiography had shown changes that did not meet diagnostic criteria), 1 pectus excavatum with compression of the right ventricle, and 1 significant pulmonary valve stenosis; the rest of the changes did not entail cessation of athletic activity and only indicated periodic monitoring. Although rare, some cardiac structural changes can be missed on physical examination and electrocardiography; in contrast, they are easily recognized with echocardiography. These findings suggest the use of echocardiography in at least the first preparticipation screening of competitive athletes to improve the effectiveness of programs aimed at preventing sudden death in athletes. Copyright © 2013 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

  12. Dobutamine stress echocardiography in healthy adult male rats

    Directory of Open Access Journals (Sweden)

    Couet Jacques

    2005-10-01

    Full Text Available Abstract Background Dobutamine stress echocardiography is used to investigate a wide variety of heart diseases in humans. Dobutamine stress echocardiography has also been used in animal models of heart disease despite the facts that the normal response of healthy rat hearts to this type of pharmacological stress testing is unknown. This study was performed to assess this normal response. Methods 15 normal adult male Wistar rats were evaluated. Increasing doses of dobutamine were infused intravenously under continuous imaging of the heart by a 12 MHz ultrasound probe. Results Dobutamine stress echocardiography reduced gradually LV diastolic and systolic dimensions. Ejection fraction increased by a mean of +24% vs. baseline. Heart rate increased progressively without reaching a plateau. Changes in LV dimensions and ejection fraction reached a plateau after a mean of 4 minutes at a constant infusion rate. Conclusion DSE can be easily performed in rats. The normal response is an increase in heart rate and ejection fraction and a decrease in LV dimensions. A plateau in echocardiographic measurements is obtained after 4 minutes of a constant infusion rate in most animals.

  13. Intracardiac Echocardiography during Catheter-Based Ablation of Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Jürgen Biermann

    2012-01-01

    Full Text Available Accurate delineation of the variable left atrial anatomy is of utmost importance during anatomically based ablation procedures for atrial fibrillation targeting the pulmonary veins and possibly other structures of the atria. Intracardiac echocardiography allows real-time visualisation of the left atrium and adjacent structures and thus facilitates precise guidance of catheter-based ablation of atrial fibrillation. In patients with abnormal anatomy of the atria and/or the interatrial septum, intracardiac ultrasound might be especially valuable to guide transseptal access. Software algorithms like CARTOSound (Biosense Webster, Diamond Bar, USA offer the opportunity to reconstruct multiple two-dimensional ultrasound fans generated by intracardiac echocardiography to a three-dimensional object which can be merged to a computed tomography or magnetic resonance imaging reconstruction of the left atrium. Intracardiac ultrasound reduces dwell time of catheters in the left atrium, fluoroscopy, and procedural time and is invaluable concerning early identification of potential adverse events. The application of intracardiac echocardiography has the great capability to improve success rates of catheter-based ablation procedures.

  14. Role of echocardiography in diagnosis of pulmonary hypertension

    Directory of Open Access Journals (Sweden)

    Srbinovska Kostovska Elizabeta

    2013-07-01

    Full Text Available Pulmonary hypertension (PH is a progressive process that leads to right ventricular (RV overload, hypertrophy, dilatation and RV failure. In cases with chronic heart failure, this condition is associated with more severe symptoms and worse outcomes.Transthoracic echocardiography can give several parameters which correlate with right heart haemodynamics, and should be performed in a case of suspected PH. Several parameters are important for estimation of the RV function, which can be reason for poor outcome: right atrial and ventricular dimensions and volumes, functional area changes, tricuspid annular plane systolic excursion (TAPSE, myocardial performance index, infe- rior vena cava size and collapsibility, S velocity estimated by Tissue Doppler Imaging, and additional information obtained from the advance echocardiograpic techniques, like strain, strain rate, three-dimensional echocardiography. Estimation of PH based on Doppler echo- cardiography measurements is not suitable for screening of mild, asymptomatic PH. Echocardiography can be recommended as a screening tool for specific diseases, follow up PH, and assessment when right heart catheterization is indicated.

  15. The use of echocardiography in the critically ill; the role of FADE (Fast Assessment Diagnostic Echocardiography) training.

    Science.gov (United States)

    Marum, Susan; Price, Susanna

    2011-08-01

    Echocardiography (echo) is a powerful technique that permits direct visualization and assessment of all the cardiac structures and assessment of the patients' haemodynamic status at the bedside. Echo allows detection of valvular disease, evaluation of ventricular function and the pericardium, detection of intracardiac/intrapulmonary shunts, and can be used to calculate flows and relative pressures between the cardiac chambers. This rapid point-of-care haemodynamic evaluation provides information to guide therapeutic interventions, including volume resuscitation, instigation of vasoactive therapy and/or referral for specialist cardiac/surgical intervention. Although there is abundant evidence in the cardiology literature regarding the use of echo, data in the critical care arena is less well defined, but emerging. The use of echo by intensive care doctors is likely to become routine, and therefore training for intensivists in this technique needs to be developed and supported. The Portuguese Working Group on Echocardiography has developed a skill-based program, FADE (Focused Assessment Diagnostic Echocardiography) in order to train clinicians in the use of bedside ultrasound as a diagnostic and monitoring tool for the critically ill.

  16. CMTO Four-dimensional Analysis Method of Competitive Intelligence and Its Application%竞争情报分析的CMTO四维分析法及其应用

    Institute of Scientific and Technical Information of China (English)

    苗红; 宋昱晓; 黄鲁成; 娄岩; 王晓宇

    2015-01-01

    Competitive intelligence analysis method is the key way to acquire the most accurate competitive intelligence It is also the basis of competitive intelligence application to be realized. This paper proposes a"Capability-Market-Time-Opportunity" four-dimensional a-nalysis method ( hereinafter referred to as CMTO four-dimensional analysis method) , which offsets the deficiency of the CMT three-di-mensional analysis for lack of direction caused by negligence of competitive opportunities analysis . And this method augments the amount of information in competitive intelligence analysis. This paper carries out empirical study on the application of CMTO four-dimensional a-nalysis method by taking wearable technology. For example,this method verifies the feasibility and superiority of CMTO. Research results show that the following fields are more competitive in the future:carrier and material, measurement, battery and circuit, etc. CMTO can help enterprises by providing fairly comprehensive, valuable intelligence information.%竞争情报分析方法是获取竞争情报最精准、最有价值的关键途径,也是竞争情报应用得以实现的基础。提出一种“市场-能力-时间-机会”四维分析方法(简称CMTO四维分析法),弥补了CMT三维分析法未考虑分析竞争机会而缺乏方向性的不足,增加了竞争情报分析的信息量。并用可穿戴技术验证了该方法的可行性及优越性。研究表明未来竞争机会较大的技术领域集中在载体和材料、测量、电池和电路装置等,为辅助企业决策提供了较为全面而有价值的情报信息。

  17. 四维彩超在胎儿先天性畸形中的临床诊断价值%Four-dimensional color Doppler ultrasound in examination in prenatal screening of fetal malformation

    Institute of Scientific and Technical Information of China (English)

    罗妙云

    2014-01-01

    目的 探讨四维彩超在胎儿先天性畸形中的诊断价值.方法 随机观察我院2012年1月至2014年1月孕中晚期孕妇1200例产前常规超声检查结果,所有孕妇均进行了二维超声和四维超声检查,并随访至产后1个月,比较二维超声和四维超声诊断胎儿先天性畸形的准确性.结果 经产后临床证实,共发现先天性胎儿畸形34例,其中神经管畸形10例,心脏畸形8例,唇腭裂7例,泌尿系畸形3例,四肢畸形3例,腹部畸形1例,其他2例.四维超声检出畸形31例,与产后符合率91.17%;漏诊3例,其中多指畸形1例,脊柱裂2例.二维超声检出畸形26例,符合率76.47%;漏诊8例,其中唇腭裂2例,多指畸形2例,脊柱裂3例,足内翻1例.二维和四维超声的诊断符合率比较差异具有统计学意义(P<0.05).结论 四维超声更能多方位、多切面观察胎儿宫内发育情况,对诊断胎儿体表畸形具有更直观和准确的判断,具有较高的临床价值.%Objective To investigate the diagnostic value of four-dimensional (4D) color Doppler ultrasound examination in prenatal screening of fetal malformation.Methods 1200 pregnant women were observed and detected by four-dimensional color Doppler and two dimensional ultrasound.The results were compared with the results confirmed by clinical pathology.Results 34 cases were detected with congenital defects; among which,10 got defects in nervous system,8 heart deformity,7 cheilopalatognathus,3 urinary tract malformation,3 limb deformity,1 abdominal deformity,and the other 2 cases.31 cases were detected with deformity by four-dimensional color Doppler,with a postpartum coincidence rate of 91.17%; and 3 cases were misdiagnosed,of which 1 case had polydactyly deformity and 2 cases spina bifida.26 cases were detected with deformity by two-dimensional ultrasony,with a postpartum coincidence rate of 76.47%; and 8 cases were misdiagnosed,of which 2 cases had cleft lip and palate,2 case polydactyly

  18. 科技社团绩效评价四维框架模型研究%A four-dimensional model for the performance evaluations of science and technology associations

    Institute of Scientific and Technical Information of China (English)

    赵立新

    2011-01-01

    The connotation of science and technology association performance evaluations is analyzed,the main elements of society are explored,and a four-dimensional model for science and technology association performance evaluation is built.Finally,the performance evaluation index system of modern science and technology associations is proposed.%本文剖析了现代科技社团绩效评价的内涵,探讨了科技社团评价的主体要素,构建了科技社团绩效评价四维模型,提出了现代科技社团绩效评价的指标体系。

  19. 从授权研究方法到授权途径的探索--基于高校教师的调查%An Analysis of Working Status of University Teachers Based on the Four Dimensional Psychological Empowerment

    Institute of Scientific and Technical Information of China (English)

    王瑞文; 刘金兰

    2014-01-01

    通过对不同视角下授权研究方法的梳理,建立了以结构授权为环境、领导授权为条件、心理授权为目标的实现有效授权的模型,并通过结构方程对796名高校教师数据样本进行授权途径的模型拟合,结果表明:结构授权对领导授权和心理授权四个维度起重要的正向影响作用;领导授权对心理授权的工作意义维度起正向影响作用,对影响力维度起负向影响作用;心理授权作为授权途径的最终环节,是进行有效授权的目标。%Based on the survey of 796 university teachers' self-evaluations of their jobs and psychological empowerment, this study establishes a structural equation model to investigate the influence of the four dimensional psychological empowerment on teaching, scientific research and social service. The results show that the four dimensional paradigm has positive impacts on the working states of the teachers, among which competence greatly influenced teaching, scientific research and social service, and significance have positive impact only on teaching. This paper analyzes the internal factors that would influence the working stair of teachers in order to provide theoretical support for the performance improvement and extend the organizational context of psychological empowerment as well.

  20. Speckle-tracking echocardiography: a new technique for assessing myocardial function

    National Research Council Canada - National Science Library

    Mondillo, Sergio; Galderisi, Maurizio; Mele, Donato; Cameli, Matteo; Lomoriello, Vincenzo Schiano; Zacà, Valerio; Ballo, Piercarlo; D'Andrea, Antonello; Muraru, Denisa; Losi, Mariangela; Agricola, Eustachio; D'Errico, Arcangelo; Buralli, Simona; Sciomer, Susanna; Nistri, Stefano; Badano, Luigi

    2011-01-01

    Speckle-tracking echocardiography has recently emerged as a quantitative ultrasound technique for accurately evaluating myocardial function by analyzing the motion of speckles identified on routine...

  1. Preventing complicated transseptal puncture with intracardiac echocardiography: case report

    Directory of Open Access Journals (Sweden)

    Temesvári András

    2005-03-01

    Full Text Available Abstract Background Recently, intracardiac echocardiography emerged as a useful tool in the electrophysiology laboratories for guiding transseptal left heart catheterizations, for avoiding thromboembolic and mechanical complications and assessing the ablation lesions characteristics. Although the value of ICE is well known, it is not a universal tool for achieving uncomplicated access to the left atrium. We present a case in which ICE led to interruption of a transseptal procedure because several risk factors for mechanical complications were revealed. Case presentation A case of a patient with paroxysmal atrial fibrillation and atrial flutter, and distorted intracardiac anatomy is presented. Intracardiac echocardiography showed a small oval fossa abouting to an enlarged aorta anteriorly. A very small distance from the interatrial septum to the left atrial free wall was seen. The latter two conditions were predisposing to a complicated transseptal puncture. According to fluoroscopy the transseptal needle had a correct position, but the intracardiac echo image showed that it was actually pointing towards the aortic root and most importantly, that it was virtually impossible to stabilize it in the fossa itself. Based on intracardiac echo findings a decision was made to limit the procedure only to ablation of the cavotricuspid isthmus and not to proceed further so as to avoid complications. Conclusion This case report illustrates the usefulness of the intracardiac echocardiography in preventing serious or even fatal complications in transseptal procedures when the cardiac anatomy is unusual or distorted. It also helps to understand the possible mechanisms of mechanical complications in cases where fluoroscopic images are apparently normal.

  2. Feasibility of diagnosis of postcardiotomy tamponade by miniaturized transesophageal echocardiography.

    Science.gov (United States)

    Hirose, Hitoshi; Gupta, Shreya; Pitcher, Harrison; Miessau, Joseph; Yang, Qiong; Yang, Jenny; Cavarocchi, Nicholas

    2014-07-01

    Pericardial tamponade after cardiac surgery is a critical diagnosis that can be difficult to diagnose using conventional cardiac monitoring. Transesophageal echocardiography can provide comprehensive information to make the diagnosis but is not always available, whereas transthoracic echocardiography has its utility limited because of the body habitus or other surgical effects. New monitoring devices, miniaturized hemodynamic transesophageal echocardiography (hTEE), which allows point of care assessment of cardiac filling and functions, may aid in diagnosis of postcardiotomy tamponade. From May 2011 to July 2013, 21 patients underwent hTEE to rule out pericardial tamponade for clinical suspicion of tamponade after open heart surgery. The hTEE images were reviewed, and the patient outcomes were analyzed. Nine patients showed no evidence of pericardial collection and did not require reexploration. Two patients showed a presence of small hematoma without ventricular compression and also did not undergo exploration. Ten patients were positive for pericardial tamponade (effusion or hematoma with ventricular compression); eight of these cases underwent emergent surgical exploration. Of the two patients who did not undergo immediate reoperation, one was managed by chest tube manipulation and the other patient underwent subsequent surgical exploration after his extensive coagulopathy was corrected by medical treatment. The diagnosis of pericardial tamponade postcardiotomy is feasible using a disposable hTEE based on our limited experience. We avoided unnecessary explorations while concomitantly made prompt diagnosis in emergent situations. The hTEE device was a valuable tool in hemodynamic management in the intensive care unit, allowing rapid evaluations. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Reliability of quantitative echocardiography in adult sheep and goats

    Directory of Open Access Journals (Sweden)

    Hallowell Gayle D

    2012-09-01

    Full Text Available Abstract Background Echocardiography is a non-invasive method for assessment of the ovine and caprine heart. Complete reference ranges for cardiac dimensions and time indices for both species are not currently available and reliability of these measurements has not been evaluated. The objectives for this study are to report reliability, normal cardiac dimensions and time indices in a large group of adult sheep and goats. Fifty-one adult sheep and forty adult goats were recruited. Full echocardiographic examinations were performed in the standing unsedated animal. All animals underwent echocardiography four times in a 72-hour period. Echocardiography was performed three times by one author and once by another. Images were stored and measured offline. Technique and measurement repeatability and reproducibility and any differences due to animal or day were evaluated. Reference ranges (mean ± 2 standard deviations were calculated for both species. Results Majority of the images obtained were of good to excellent quality. Image acquisition was straightforward with 5.4% of animals demonstrating a small scanning window. Reliability was excellent for majority of dimensions and time indices. There was less variation in repeatability when compared with reproducibility and differences were greater for technique than for measurements. Dimensions that were less reliable included those for right ventricular diameter and left ventricular free wall. There were many differences in cardiac dimensions between sheep and goats. Conclusions This study has demonstrated that specific reference ranges are required for these two species. Repeatability and reproducibility were excellent for the majority of cardiac dimensions and time indices suggesting that this technique is reliable and valuable for examination of clinical cases over time and for longitudinal research studies.

  4. Evaluation of diastolic function in hypertensive using echocardiography

    Directory of Open Access Journals (Sweden)

    Yamini Lavanya

    2015-09-01

    Results: The trans-mitral inflow parameters on Doppler echocardiography such as E wave deceleration time (DT, isovolumetric relaxation time (IVRT and early to late transmitral peak flow velocities ratio (E/A were significantly different in hypertensive subjects on treatment having normal ejection fraction, when compared to normotensive subjects. We observed a decrease in E/A ratio and increase in DT, IVRT with hypertension. Conclusions: From the present study it can be concluded that hypertension is significantly associated with diastolic dysfunction of heart, even in subjects with normal systolic function. [Int J Res Med Sci 2015; 3(9.000: 2274-2279

  5. Echocardiography for the Assessment of Congenital Heart Defects in Calves.

    Science.gov (United States)

    Mitchell, Katharyn Jean; Schwarzwald, Colin Claudio

    2016-03-01

    Congenital heart disease should be considered when evaluating calves with chronic respiratory signs, failure to thrive, poor growth, or if a murmur is heard on physical examination. Echocardiography is currently the gold standard for diagnosing congenital heart defects. A wide variety of defects, either alone or in combination with a ventricular septal defect, are possible. A standardized approach using sequential segmental analysis is required to fully appreciate the nature and severity of more complex malformations. The prognosis for survival varies from guarded to poor and depends on the hemodynamic relevance of the defects and the degree of cardiac compensation.

  6. Three-dimensional transesophageal echocardiography: Principles and clinical applications

    Directory of Open Access Journals (Sweden)

    Annette Vegas

    2016-01-01

    Full Text Available A basic understanding of evolving 3D technology enables the echocardiographer to master the new skills necessary to acquire, manipulate, and interpret 3D datasets. Single button activation of specific 3D imaging modes for both TEE and transthoracic echocardiography (TTE matrix array probes include (a live, (b zoom, (c full volume (FV, and (d color Doppler FV. Evaluation of regional LV wall motion by RT 3D TEE is based on a change in LV chamber subvolume over time from altered segmental myocardial contractility. Unlike standard 2D TEE, there is no direct measurement of myocardial thickening or displacement of individual segments.

  7. Speckle tracking echocardiography in mature Irish Wolfhound dogs

    DEFF Research Database (Denmark)

    Westrup, Ulrik; McEvoy, Fintan

    2013-01-01

    Two-dimensional strain measurements obtained by speckle tracking echocardiography (STE) have been reported in both humans and dogs. Incorporation of this technique into canine clinical practice requires the availability of measurements from clinically normal dogs, ideally of the same breed, taken...... under normal clinical conditions.The aims of this prospective study were to assess if it is possible to obtain STE data during a routine echocardiographic examination in Irish Wolfhound dogs and that these data will provide reference values and an estimation of measurement error....

  8. Four-dimensional ultrafast electron microscopy.

    Science.gov (United States)

    Lobastov, Vladimir A; Srinivasan, Ramesh; Zewail, Ahmed H

    2005-05-17

    Electron microscopy is arguably the most powerful tool for spatial imaging of structures. As such, 2D and 3D microscopies provide static structures with subnanometer and increasingly with angstrom-scale spatial resolution. Here we report the development of 4D ultrafast electron microscopy, whose capability imparts another dimension to imaging in general and to dynamics in particular. We demonstrate its versatility by recording images and diffraction patterns of crystalline and amorphous materials and images of biological cells. The electron packets, which were generated with femtosecond laser pulses, have a de Broglie wavelength of 0.0335 angstroms at 120 keV and have as low as one electron per pulse. With such few particles, doses of few electrons per square ångstrom, and ultrafast temporal duration, the long sought after but hitherto unrealized quest for ultrafast electron microscopy has been realized. Ultrafast electron microscopy should have an impact on all areas of microscopy, including biological imaging.

  9. Recent developments in four-dimensional supergravity

    Science.gov (United States)

    Sharpe, Eric

    2011-10-01

    I will summarize recent work on gauge theories in supergravity, specifically concerning the `Fayet-Iliopoulos' parameter. In rigidly supersymmetric gauge theories, this parameter also appears and can vary continuously. In supergravity old lore held that it should always vanish. I will discuss recent developments showing that in fact it can be nonzero, but is quantized, and will explore various ramifications of that result.

  10. Four-dimensional CDT with toroidal topology

    Directory of Open Access Journals (Sweden)

    J. Ambjørn

    2017-09-01

    Full Text Available 3+1 dimensional Causal Dynamical Triangulations (CDT describe a quantum theory of fluctuating geometries without the introduction of a background geometry. If the topology of space is constrained to be that of a three-dimensional torus we show that the system will fluctuate around a dynamically formed background geometry which can be understood from a simple minisuperspace action which contains both a classical part and a quantum part. We determine this action by integrating out degrees of freedom in the full model, as well as by transfer matrix methods.

  11. Multidirectional four-dimensional shape measurement system

    Science.gov (United States)

    Lenar, Janusz; Sitnik, Robert; Witkowski, Marcin

    2012-03-01

    Currently, a lot of different scanning techniques are used for 3D imaging of human body. Most of existing systems are based on static registration of internal structures using MRI or CT techniques as well as 3D scanning of outer surface of human body by laser triangulation or structured light methods. On the other hand there is an existing mature 4D method based on tracking in time the position of retro-reflective markers attached to human body. There are two main drawbacks of this solution: markers are attached to skin (no real skeleton movement is registered) and it gives (x, y, z, t) coordinates only in those points (not for the whole surface). In this paper we present a novel multidirectional structured light measurement system that is capable of measuring 3D shape of human body surface with frequency reaching 60Hz. The developed system consists of two spectrally separated and hardware-synchronized 4D measurement heads. The principle of the measurement is based on single frame analysis. Projected frame is composed from sine-modulated intensity pattern and a special stripe allowing absolute phase measurement. Several different geometrical set-ups will be proposed depending on type of movements that are to be registered.

  12. A Four-Dimensional Product Innovativeness Typology

    DEFF Research Database (Denmark)

    Rosenø, Axel

    2005-01-01

    Product innovativeness is a key moderating variable for the study of innovationmanagement (Song & Montoya-Weiss 1998, p. 124). For this reason, some empiricalstudies of innovation management examine new product processes, critical successfactors, and market learning practices for incremental versus......) typology with four newproduct types; Leonard-Barton's (1995) five product types; and Veryzer's (1998a)four types in a two-by-two matrix.Interestingly, these two meta-perspectives on product innovativeness (i.e. 1. new tothe market and/or new to the company and 2. technological and/or marketnewness...... discontinuous newproduct projects (Song & Montoya-Weiss 1998; Atuahene-Gima 1995; Veryzer 1998a;Lynn et al. 1996; O'Connor 1998; Rice et al. 1998). By looking at both these types ofnew product development projects, empirical observations are likely to be morerealistic than those of studies that do...

  13. Potential applications for transesophageal echocardiography in hypertrophic cardiomyopathies.

    Science.gov (United States)

    Widimsky, P; Ten Cate, F J; Vletter, W; van Herwerden, L

    1992-01-01

    The purpose of the present study was to evaluate the potential advantages of transesophageal echocardiography (TEE) in comparison with transthoracic echocardiography (TTE) in selected patients with hypertrophic cardiomyopathy. Ten patients with previously established or suspected diagnosis of hypertrophic cardiomyopathy were examined by TEE to solve specific clinical questions. TEE was well tolerated by all patients; no arrhythmias were seen during the procedure. The comparison of TTE and TEE showed the following: Advantages of TTE--better assessment of the left ventricle, myocardial thickness measurements available in all regions and sufficient for the diagnosis of hypertrophic cardiomyopathy in nine out of 10 patients; advantages of TEE--precise assessment of mitral valve morphology and regurgitant jets, detailed evaluation of systolic anterior motion, and subaortic membrane (not seen by TTE) recognized in one patient. Clinically, in three patients TEE influenced the management (mitral leaflet perforation, subaortic membrane, and residual mitral regurgitation after valvuloplasty). Thus TEE enables more precise diagnosis in some patients with hypertrophic cardiomyopathy and has the potential to influence their surgical management. However, for medical treatment of hypertrophic cardiomyopathy, TTE is sufficient.

  14. Healed perivalvular abscess: Incidental finding on transthoracic echocardiography

    Directory of Open Access Journals (Sweden)

    Vishnu Datt

    2014-01-01

    Full Text Available A 36-year-old male patient presented with the complaints of palpitations and breathlessness. Preoperative transthoracic echocardiography (TTE revealed a bicuspid aortic valve; severe aortic regurgitation with dilated left ventricle (LV and mild LV systolic dysfunction (ejection fraction 50%. He was scheduled to undergo aortic valve replacement. History was not suggestive of infective endocarditis (IE. Preoperative TTE did not demonstrate any aortic perivalvular abscess. Intraoperative transesophageal echocardiography (TEE examination using the mid-esophageal (ME long-axis view, showed an abscess cavity affecting the aortic valve, which initially was assumed to be a dissection flap, but later confirmed to be an abscess cavity by color Doppler examination. The ME aortic valve short-axis view showed two abscesses; one was at the junction of the non-coronary and left coronary commissure and the other one above the right coronary cusp. Intraoperatively, these findings were confirmed by the surgeons. The case report demonstrates the superiority of TEE over TTE in diagnosing perivalvular abscesses.

  15. EchoComTEE - a simulator for transoesophageal echocardiography.

    Science.gov (United States)

    Weidenbach, M; Drachsler, H; Wild, F; Kreutter, S; Razek, V; Grunst, G; Ender, J; Berlage, T; Janousek, J

    2007-04-01

    Transoesophageal echocardiography (TOE) requires extensive hands-on training, and it is for this purpose we have designed EchoComTEE, a simulator for TOE. It consists of a manikin and dummy probe; according to the position of the dummy probe (tracked by an electromagnetic sensor), two-dimensional (2D) images are calculated from three-dimensional (3D) data sets. Echocardiographic images are presented side-by-side with a virtual scene consisting of a 3D heart, probe tip and image plane. In this way the trainee is provided with visual feed-back of the relationship between echocardiogram and image plane position. We evaluated the simulator using a standardised questionnaire. Twenty-five experts and 31 novice users participated in the study. Most experts graded the simulator as realistic and all recommended its use for training. Most novice users felt the simulator supported spatial orientation during TOE and, as anaesthetists often do not have training in transthoracic echocardiography, in this group the TOE simulator might be particularly useful.

  16. Advanced echocardiography and clinical surrogates to risk stratify and manage patients with structural heart disease

    NARCIS (Netherlands)

    Debonnaire, Philippe Jean Marc Rita

    2016-01-01

    Part I focuses on the potential role of 3-dimensional echocardiography. At first a clinical risk score model for prediction of outcome in patients undergoing TAVI is presented (Chapter 2). Second the role of 3D-echocardiography is explored in depth in patients with mitral valve disease. Different no

  17. Advanced echocardiography and clinical surrogates to risk stratify and manage patients with structural heart disease

    NARCIS (Netherlands)

    Debonnaire, Philippe Jean Marc Rita

    2016-01-01

    Part I focuses on the potential role of 3-dimensional echocardiography. At first a clinical risk score model for prediction of outcome in patients undergoing TAVI is presented (Chapter 2). Second the role of 3D-echocardiography is explored in depth in patients with mitral valve disease. Different

  18. Strain Echocardiography Improves Risk Prediction of Ventricular Arrhythmias After Myocardial Infarction

    DEFF Research Database (Denmark)

    Haugaa, Kristina H; Grenne, Bjørnar L; Eek, Christian H;

    2013-01-01

    The aim of this study was to test the hypothesis that strain echocardiography might improve arrhythmic risk stratification in patients after myocardial infarction (MI).......The aim of this study was to test the hypothesis that strain echocardiography might improve arrhythmic risk stratification in patients after myocardial infarction (MI)....

  19. The best of 2005 in echocardiography back from EuroEcho 9 – Florence, Italy

    Directory of Open Access Journals (Sweden)

    Sicari Rosa

    2006-02-01

    Full Text Available Abstract The ninth edition of the congress of the European Association of Echocardiography (EAE (former working group of Echocardiography held in Florence has just finished with a great success of participant attendance (2.842 and abstract submissions. Hot topics at EuroEcho 9 were: 1-live 3-dimensional echocardiography and surgical decision making; in pediatric cardiology; in resynchronization therapy 2- stress echocardiography beyond wall motion: from valve diseases to contractility to coronary flow reserve to diastolic function; 3- pulmonary cardiogenic interstitial thickening recognized by ultrasonic lung comets; 4- the "proven clinical inefficacy" of the many technologies sold as breakthrough: color kinesis, tissue characterization, strain rate, tissue Doppler, applied to stress echocardiography.

  20. The diagnostic ability of echocardiography for infective endocarditis and its associated complications.

    Science.gov (United States)

    Vilacosta, Isidre; Olmos, Carmen; de Agustín, Alberto; López, Javier; Islas, Fabián; Sarriá, Cristina; Ferrera, Carlos; Ortiz-Bautista, Carlos; Sánchez-Enrique, Cristina; Vivas, David; San Román, Alberto

    2015-11-01

    Echocardiography, transthoracic and transoesophageal, plays a key role in the diagnosis and prognosis assessment of patients with infective endocarditis. It constitutes a major Duke criterion and is pivotal in treatment guiding. Seven echocardiographic findings are major criteria in the diagnosis of infective endocarditis (IE) (vegetation, abscess, pseudoaneurysm, fistulae, new dehiscence of a prosthetic valve, perforation and valve aneurysm). Echocardiography must be performed as soon as endocarditis is suspected. Transoesophageal echocardiography should be done in most cases of left-sided endocarditis to better define the anatomic lesions and to rule out local complications. Transoesophageal echocardiography is not necessary in isolated right-sided native valve IE with good quality transthoracic examination and unequivocal echocardiographic findings. Echocardiography is a very useful tool to assess the prognosis of patients with IE at any time during the course of the disease. Echocardiographic predictors of poor outcome include presence of periannular complications, prosthetic dysfunction, low left ventricular ejection fraction, pulmonary hypertension and very large vegetations.

  1. Reduction of N=1, E{sub 8} SYM over SU(3)/U(1)xU(1)xZ{sub 3} and its four-dimensional effective action

    Energy Technology Data Exchange (ETDEWEB)

    Irges, Nikos, E-mail: irges@mail.ntua.g [Department of Physics, National Technical University of Athens, Zografou Campus, GR-15780 Athens (Greece); Zoupanos, George [Institut fuer Theoretische Physik, Universitaet Heidelberg, Philosophenweg 16, D-69120 Heidelberg (Germany); Department of Physics, National Technical University of Athens, Zografou Campus, GR-15780 Athens (Greece)

    2011-04-04

    We propose an extension of the Standard Model inspired by the E{sub 8}xE{sub 8} Heterotic String. In order that a reasonable effective Lagrangian is presented we neglect everything else other than the ten-dimensional N=1 supersymmetric Yang-Mills sector associated with one of the gauge factors and certain couplings necessary for anomaly cancellation. We consider a compactified space-time M{sub 4}xB{sub 0}/Z{sub 3}, where B{sub 0} is the nearly Kaehler manifold SU(3)/U(1)xU(1) and Z{sub 3} is a freely acting discrete group on B{sub 0}. Then we reduce dimensionally the E{sub 8} on this manifold and we employ the Wilson flux mechanism leading in four dimensions to an SU(3){sup 3} gauge theory with the spectrum of a N=1 supersymmetric theory. We compute the effective four-dimensional Lagrangian and demonstrate that an extension of the Standard Model is obtained with interesting features including a conserved baryon number and fixed tree level Yukawa couplings and scalar potential. The spectrum contains new states such as right-handed neutrinos and heavy vector-like quarks.

  2. Increased clutter level in echocardiography due to specular reflection

    Science.gov (United States)

    Fatemi, Ali; Torp, Hans; Aakhus, Svend; Rodriguez-Molares, Alfonso

    2017-03-01

    State-of-the-art echocardiography allows to correctly diagnose most of cardiovascular diseases. An unknown source of clutter, however, hinders the visualization of the heart in some cases. We believe this clutter is caused by the ultrasound beam being partially reflected by the ribs into the elevation direction, so that structures outside the imaging plane are displayed on top of the heart image as clutter noise. We conducted in vitro experiments in a water tank using a synthetic ventricle and pig ribs. By partially blocking the probe with the ribs in the elevation direction, objects outside the imaging plane were rendered in the B-mode image, which confirms that the ribs can behave as specular reflectors. In addition, we succeeded in reproducing clutter noise using a piece of polystyrene to simulate the reflections from the lungs. This indicates that the origin of the clutter noise in echocardiograms can be reverberation coming from the lungs via specular reflection at the ribs.

  3. Echocardiography and heart failure: a glimpse of the right heart.

    Science.gov (United States)

    Pleister, Adam; Kahwash, Rami; Haas, Garrie; Ghio, Stefano; Cittadini, Antonio; Baliga, Ragavendra R

    2015-01-01

    The catastrophic consequences for patients in the settings of certain clinical conditions such as acute right ventricular infarction or massive pulmonary embolism with right heart failure illustrate the essential role that the right ventricle plays in sustaining life. With the development of more sophisticated diagnostic imaging technologies at the end of the last century and the dawn of this century, the importance of the right ventricle has been clearly demonstrated. The continued and evolving nature of our understanding of the right ventricle was emphasized in 2006, when the National Heart, Blood, and Lung Institute formed a working group focused on developing a better understanding of the right ventricle in both healthy and disease states. The objective of this review paper is to examine the right ventricle structure and function and describe the role of echocardiography in the evaluation of the right ventricle and right heart failure. Special focus will be on echocardiographic images and major society guidelines. © 2014, Wiley Periodicals, Inc.

  4. Hypnosis for sedation in transesophageal echocardiography: a comparison with midazolam.

    Science.gov (United States)

    Eren, Gulay; Dogan, Yuksel; Demir, Guray; Tulubas, Evrim; Hergunsel, Oya; Tekdos, Yasemin; Dogan, Murat; Bilgi, Deniz; Abut, Yesim

    2015-01-01

    Transesophageal echocardiography (TEE), being a displeasing intervention, usually entails sedation. We aimed to compare the effects of hypnosis and midazolam for sedation in TEE. A prospective single-blinded study conducted on patients scheduled for TEE between April 2011 and July 2011 at a university in Istanbul, Turkey. A total of 41 patients underwent sedation using midazolam and 45 patients underwent hypnosis. Patients were given the State-Trait Anxiety Inventory (STAI) test for anxiety and continuous performance test (CPT) for alertness before and after the procedure. The difficulty of probing and the overall procedure rated by the cardiologist and satisfaction scores of the patients were also documented. Anxiety was found to be less and attention more in the hypnosis group, as revealed by STAI and CPT test scores (P Hypnosis proved to be associated with positive therapeutic outcomes for TEE with regard to alleviation of anxiety and maintenance of vigilance, thus providing more satisfaction compared to sedation with midazolam.

  5. Imaging Aortic Regurgitation: The Incremental Benefit of Speckle Tracking Echocardiography

    Science.gov (United States)

    Garg, Pankaj; Yassin, Firas; Leischik, Roman

    2015-01-01

    Aortic regurgitation (AR) affects global left ventricular mechanics. However, limited literature is available on how it may affect regional longitudinal strain. We present a case where severe AR jet is thrashing the anterior-septal wall and reducing its overall longitudinal performance most likely secondary to increased wall shear stress in diastole. This new insight into patho-physiological process using deformation study may have supplementary impact in decision making for surgical intervention. Transthoracic echocardiography is the primary imaging modality for the assessment of AR as it offers evaluation of severity of AR, aetiology of AR, left ventricular (LV) dilatation, LV systolic function, left ventricular mass, diastolic function and global strain. This case highlights the regional disturbances in longitudinal strain in eccentric AR. PMID:27006711

  6. [Peculiarities of the transesophageal echocardiography in octogenarian patients].

    Science.gov (United States)

    Canale, Jesús M; Cardoza-Encinas, Rubén; Canale-Segovia, Andrés

    The growing trend in the absolute and relative number of elderly in the population scheme, the increasing prevalence of heart disease as people get older and the impressive technological development of ultrasound devices have all together recently contributed to promote an increasing number of transesophageal echocardiograms in older patients, however, the already published information about the distinguishing features of this diagnostic methodology in elderly patients is still scarce and seems to be insufficient. This review focuses on the already published methodological and diagnostic features related to the transesophageal echocardiography in the octogenarian -or even older patient- in order to show them in an orderly and systematic manner to provide elements that induce useful clinical criteria for the physician who attends patients in this age group in whom this diagnostic modality is now increasingly requested. Copyright © 2016 Instituto Nacional de Cardiología Ignacio Chávez. Publicado por Masson Doyma México S.A. All rights reserved.

  7. Transesophageal echocardiography in patients with cryptogenic cerebral ischemia

    Directory of Open Access Journals (Sweden)

    Dreger Henryk

    2009-03-01

    Full Text Available Abstract Background In about one third of all patients with cerebral ischemia, no definite cause can be identified (cryptogenic stroke. In many patients with initially suspected cryptogenic stroke, however, a cardiogenic etiology can eventually be determined. Hence, the aim of this study was to describe the prevalence of abnormal echocardiographic findings in a large number of these patients. Method Patients with cryptogenic cerebral ischemia (ischemic stroke, IS, and transient ischemic attack, TIA were included. The initial work-up included a neurological examination, EEG, cCT, cMRT, 12-lead ECG, Holter-ECG, Doppler ultrasound of the extracranial arteries, and transthoracic echocardiography. A multiplane transeophageal echocardiography (TEE, including i.v. contrast medium application [Echovist], Valsalva maneuver was performed in all patients Results 702 consecutive patients (380 male, 383 IS, 319 TIA, age 18–90 years were included. In 52.6% of all patients, TEE examination revealed relevant findings. Overall, the most common findings in all patients were: patent foramen ovale (21.7%, previously undiagnosed valvular disease (15.8%, aortic plaques, aortic valve sclerosis, atrial septal aneurysms, regional myocardial dyskinesia, dilated left atrium and atrial septal defects. Older patients (> 55 years, n = 291 and patients with IS had more relevant echocardiographic findings than younger patients or patients with TIA, respectively (p = 0.002, p = 0.003. The prevalence rates of PFO or ASD were higher in younger patients (PFO: 26.8% vs. 18.0%, p = 0.005, ASD: 9.6% vs. 4.9%, p = 0.014. Conclusion A TEE examination in cryptogenic stroke reveals contributing cardiogenic factors in about half of all patients. Younger patients had a higher prevalence of PFO, whereas older patients had more frequently atherosclerotic findings. Therefore, TEE examinations seem indicated in all patients with cryptogenic stroke – irrespective of age – because of

  8. Low Prevalance of Major Events Adverse to Exercise Stress Echocardiography

    Science.gov (United States)

    Andrade, Stephanie Macedo; Telino, Caio José Coutinho Leal; Sousa, Antônio Carlos Sobral; de Melo, Enaldo Vieira; Teixeira, Carla Carolina Cardoso; Teixeira, Clarissa Karine Cardoso; Santana, Jaquiele Santos; Mota, Igor Larchert; de Matos, Carlos José Oliveira; Oliveira, Joselina Luzia Menezes

    2016-01-01

    Background: Stress echocardiography is well validated for diagnosis and risk stratification of coronary artery disease. Exercise stress echocardiography (ESE) has been shown to be the most physiological among the modalities of stress, but its safety is not well established. Objective: To study the complications related to ESE and clinical and echocardiographic variables most commonly associated with their occurrence. Methods: Cross-sectional study consisting of 10250 patients submitted to ESE for convenience, from January 2000 to June 2014. Cardiac Arrhythmias (CA) were the most frequent complications observed during the examination. The volunteers were divided into two groups according to the occurrence of CA during ESE: G1 group, composed of patients who have CA, and G2 formed by individuals who did not show such complication. Results: Group G1, consisting of 2843 patients (27.7%), and Group G2 consisting of 7407 patients (72.3%). There was no death, acute myocardial infarction, ventricular fibrillation or asystole. Predominant CAs were: supraventricular extrasystoles (13.7%), and ventricular extrasystoles (11.5%). G1 group had a higher mean age, higher frequency of hypertension and smoking, larger aortic roots and left atrium (LA) and lower ejection fraction than G2. G1 group also had more ischemic changes (p < 0.001). The predictor variables were age (RR 1.04; [CI] 95% from 1.038 to 1.049) and LA (RR 1.64; [CI] 95% from 1.448 to 1.872). Conclusion: ESE proved to be a safe modality of stress, with non-fatal complications only. Advanced age and enlargement of the left atrium are predictive of cardiac arrhythmias. PMID:27355587

  9. Repeated bedside echocardiography in children with respiratory failure

    Directory of Open Access Journals (Sweden)

    Jehlicka Petr

    2011-04-01

    Full Text Available Abstract Background The aim of this study was to verify the benefits and limitations of repeated bedside echocardiographic examinations in children during mechanical ventilation. For the purposes of this study, we selected the data of over a time period from 2006 to 2010. Methods A total of 235 children, average age 3.21 (SD 1.32 years were included into the study and divided into etiopathogenic groups. High-risk groups comprised: Acute lung injury and acute respiratory distress syndrome (ALI/ARDS, return of spontaneous circulation after cardiopulmonary resuscitation (ROSC, bronchopulmonary dysplasia (BPD, cardiomyopathy (CMP and cardiopulmonary disease (CPD. Transthoracic echocardiography was carried out during mechanical ventilation. The following data were collated for statistical evaluation: right and left ventricle myocardial performance indices (RV MPI; LV MPI, left ventricle shortening fraction (SF, cardiac output (CO, and the mitral valve ratio of peak velocity of early wave (E to the peak velocity of active wave (A as E/A ratio. The data was processed after a period of recovery, i.e. one hour after the introduction of invasive lines (time-1 and after 72 hours of comprehensive treatment (time-2. The overall development of parameters over time was compared within groups and between groups using the distribution-free Wilcoxons and two-way ANOVA tests. Results A total of 870 echocardiographic examinations were performed. At time-1 higher average values of RV MPI (0.34, SD 0.01 vs. 0.21, SD 0.01; p Conclusion Echocardiography complements standard monitoring of valuable information regarding cardiac load in real time. Chest excursion during mechanical ventilation does not reduce the quality of the acquired data.

  10. On-orbit prospective echocardiography on International Space Station crew.

    Science.gov (United States)

    Hamilton, Douglas R; Sargsyan, Ashot E; Martin, David S; Garcia, Kathleen M; Melton, Shannon L; Feiveson, Alan; Dulchavsky, Scott A

    2011-05-01

    A prospective trial of echocardiography was conducted on six crew members onboard the International Space Station. The main objective was to determine the efficacy of remotely guided tele-echocardiography, including just-in-time e-training methods and determine what is "space normal" echocardiographic data. Each crew member operator (n = 6) had 2-hour preflight training. Baseline echocardiographic data were collected 55-167 days preflight. Similar equipment was used in each 60-minute in-flight session (mean microgravity exposure--114 days [34--190]). On-orbit ultrasound (US) operators used an e-learning system within 24 hours of these sessions. Expert assistance was provided using US video downlink and two-way voice. Testing was repeated 5-16 days after landing. Separate ANOVA was used on each echocardiographic variable (n = 33). Within each ANOVA, three tests were made: (a) effect of mission phase (preflight, in-flight, postflight); (b) effect of echo technician (two technicians independently analyzed the data); (c) interaction between mission phase and technician. Eleven rejections of the null hypothesis (mission phase or technician or both had no effect) were found that could be considered for possible follow up. Of these, eight rejections were for significant technician effects, not space flight. Three rejections of the null hypothesis (aortic valve time velocity integral, mitral E-wave velocity, and heart rate) were attributable to space flight but determine to not be clinically significant. No rejections were due to the interaction between technician and space flight. Thus, we found no consistent clinically significant effects of long-duration space flight on echocardiographic variables of the given group of subjects. © 2011, Wiley Periodicals, Inc.

  11. 4-D flow magnetic resonance imaging: blood flow quantification compared to 2-D phase-contrast magnetic resonance imaging and Doppler echocardiography

    Energy Technology Data Exchange (ETDEWEB)

    Gabbour, Maya [Ann and Robert H. Lurie Children' s Hospital of Chicago, Department of Medical Imaging 9, Chicago, IL (United States); Schnell, Susanne [Northwestern University Feinberg School of Medicine, Department of Radiology, Chicago, IL (United States); Jarvis, Kelly [Northwestern University, Department of Biomedical Engineering, McCormick School of Engineering, Evanston, IL (United States); Robinson, Joshua D. [Ann and Robert H. Lurie Children' s Hospital of Chicago, Department of Pediatrics, Division of Pediatric Cardiology, Chicago, IL (United States); Northwestern University Feinberg School of Medicine, Department of Pediatrics, Chicago, IL (United States); Markl, Michael [Northwestern University Feinberg School of Medicine, Department of Radiology, Chicago, IL (United States); Northwestern University, Department of Biomedical Engineering, McCormick School of Engineering, Evanston, IL (United States); Rigsby, Cynthia K. [Ann and Robert H. Lurie Children' s Hospital of Chicago, Department of Medical Imaging 9, Chicago, IL (United States); Northwestern University Feinberg School of Medicine, Department of Radiology, Chicago, IL (United States)

    2015-06-15

    Doppler echocardiography (echo) is the reference standard for blood flow velocity analysis, and two-dimensional (2-D) phase-contrast magnetic resonance imaging (MRI) is considered the reference standard for quantitative blood flow assessment. However, both clinical standard-of-care techniques are limited by 2-D acquisitions and single-direction velocity encoding and may make them inadequate to assess the complex three-dimensional hemodynamics seen in congenital heart disease. Four-dimensional flow MRI (4-D flow) enables qualitative and quantitative analysis of complex blood flow in the heart and great arteries. The objectives of this study are to compare 4-D flow with 2-D phase-contrast MRI for quantification of aortic and pulmonary flow and to evaluate the advantage of 4-D flow-based volumetric flow analysis compared to 2-D phase-contrast MRI and echo for peak velocity assessment in children and young adults. Two-dimensional phase-contrast MRI of the aortic root, main pulmonary artery (MPA), and right and left pulmonary arteries (RPA, LPA) and 4-D flow with volumetric coverage of the aorta and pulmonary arteries were performed in 50 patients (mean age: 13.1 ± 6.4 years). Four-dimensional flow analyses included calculation of net flow and regurgitant fraction with 4-D flow analysis planes similarly positioned to 2-D planes. In addition, 4-D flow volumetric assessment of aortic root/ascending aorta and MPA peak velocities was performed and compared to 2-D phase-contrast MRI and echo. Excellent correlation and agreement were found between 2-D phase-contrast MRI and 4-D flow for net flow (r = 0.97, P < 0.001) and excellent correlation with good agreement was found for regurgitant fraction (r = 0.88, P < 0.001) in all vessels. Two-dimensional phase-contrast MRI significantly underestimated aortic (P = 0.032) and MPA (P < 0.001) peak velocities compared to echo, while volumetric 4-D flow analysis resulted in higher (aortic: P = 0.001) or similar (MPA: P = 0.98) peak

  12. The search for endocarditis in patients with candidemia: a systematic recommendation for echocardiography? A prospective cohort.

    Science.gov (United States)

    Fernández-Cruz, A; Cruz Menárguez, M; Muñoz, P; Pedromingo, M; Peláez, T; Solís, J; Rodríguez-Créixems, M; Bouza, E

    2015-08-01

    Most current guidelines do not recommend systematic screening with echocardiography in patients with candidemia, as Candida infective endocarditis (CIE) is considered an uncommon disease. During the study period, we recommended echocardiography systematically to all candidemic patients that did not have contraindications and accepted to participate in the study. We intended to assess the incidence of unrecognized CIE in adult patients with candidemia. Our institution is a tertiary teaching hospital in which we follow all patients with candidemia. From January 2007 to October 2012, echocardiography was systematically recommended to suitable candidates. We recorded 263 cases of candidemia in adult patients. Echocardiography was not performed in 76 of these patients for the following reasons: patients had died when blood cultures became positive (17), patients were critically or terminally ill (38), or the patient or physician refused the procedure (21). The remaining 187 patients constitute the basis of this report. CIE was diagnosed in 11 cases (4.2 % of the whole candidemic population and 5.9 % of the population with echocardiographic study). The results of transthoracic echocardiography (TTE) suggested infective endocarditis (IE) in 5/172 patients (2.9 %), and the result of transesophageal echocardiography (TEE) was positive in 10/87 (11.5 %). Among 11 confirmed cases of CIE, the disease was clinically unsuspected in three patients. At least 4.2 % of all candidemic patients have CIE. CIE is frequently clinically unsuspected and echocardiography is required to demonstrate a high proportion of cases.

  13. Saline contrast echocardiography for the detection of patent foramen ovale in hypoxia: a validation study using intracardiac echocardiography.

    Science.gov (United States)

    Fenster, Brett E; Curran-Everett, Douglas; Freeman, Andrew M; Weinberger, Howard D; Kern Buckner, J; Carroll, John D

    2014-04-01

    Although the "3 beat rule" is widely utiized to discriminate patent foramen ovale (PFO)-mediated right-to-left shunt (RTLS) from intrapulmonary RTLS using saline contrast transthoracic echocardiography (SCE), SCE diagnostic performance has yet to be validated using an invasive intracardiac standard. Percutaneous PFO occluder placement was recently shown to ameliorate hypoxia in patients with suspected PFO-mediated RTLS. We evaluated the ability of SCE to predict PFO presence and size using intracardiac echocardiography (ICE) as a gold standard in a hypoxic cohort. Sixty-three hypoxic patients with suspected PFO-mediated RTLS who underwent SCE at rest, with Valsalva maneuver, and with cough prior to ICE were evaluated retrospectively. PFO RTLS was defined by ICE findings including PFO anatomy, RTLS by saline contrast and color Doppler, and probe patency. SCE shunt severity and timing of left heart saline target appearance were compared to the presence of ICE-defined PFO RTLS. Forty-seven patients (75%) met criteria for PFO-mediated RTLS. A 4 beat cutoff for resting SCE provided optimal diagnostic performance for detection of PFO-mediated RTLS with a 71% sensitivity, 94% specificity, and 97% positive predictive value (PPV). Valsalva and cough maneuvers improved sensitivity compared to rest SCE (89% and 80%, respectively). Valsalva SCE shunt severity more accurately predicted PFO size than resting SCE. In contrast to the widely accepted "3 beat rule," resting SCE for the detection of PFO RTLS in a hypoxic population performs optimally using a 4-cycle cutoff with both excellent specificity and PPV. © 2013, Wiley Periodicals, Inc.

  14. DOBUTAMINE STRESS-ECHOCARDIOGRAPHY: POSSIBILITY OF CLINICAL USAGE IN CARDIOLOGY PRACTICE

    Directory of Open Access Journals (Sweden)

    M. A. Saidova

    2016-01-01

    Full Text Available Currently stress-echocardiography or so-called burden echocardiography is essential method of patient examination to reveal latent ischemic heart disease (IHD. That is one of the mostly informative non-invasive methods of IHD diagnosis as well as efficacy evaluation of coronary angioplasty, surgical and pharmacological treatments of IHD. Dobutamine usage as a stress-agent at burden echocardiography allows evaluating not only ischemia but a myocardial vitality in post infarction area as well as clarify severity of valve stenosis, pulmonary hypertension and extent of latent obstruction of exhaust duct of the left ventricle. Method possibilities are presented as well as test protocol, main indications and contraindications.

  15. 3-dimensional echocardiography and its role in preoperative mitral valve evaluation.

    Science.gov (United States)

    Andrawes, Michael N; Feinman, Jared W

    2013-05-01

    Echocardiography plays a key role in the preoperative evaluation of mitral valve disease. 3-dimensional echocardiography is a relatively new development that is being used more and more frequently in the evaluation of these patients. This article reviews the available literature comparing the use of this new technology to classic techniques in the assessment of mitral valve pathology. The authors also review some of the novel insights learned from 3-dimensional echocardiography and how they may be used in surgical decision making and planning.

  16. Targeted neonatal echocardiography services: need for standardized training and quality assurance.

    LENUS (Irish Health Repository)

    Finan, Emer

    2014-10-01

    Targeted neonatal echocardiography refers to a focused assessment of myocardial performance and hemodynamics directed by a specific clinical question. It has become the standard of care in many parts of the world, but practice is variable, and there has been a lack of standardized training and evaluation to date. Targeted neonatal echocardiography was first introduced to Canada in 2006. The purpose of this study was to examine the characteristics of targeted neonatal echocardiography practice and training methods in Canadian neonatal intensive care units (NICUs).

  17. Respiratory influence on left atrial volume calculation with 3D-echocardiography

    DEFF Research Database (Denmark)

    Sørgaard, Mathias; Linde, Jesper J; Ismail, Hafsa;

    2016-01-01

    BACKGROUND: Left atrial volume (LAV) estimation with 3D echocardiography has been shown to be more accurate than 2D volume calculation. However, little is known about the possible effect of respiratory movements on the accuracy of the measurement. METHODS: 100 consecutive patients admitted...... with chest pain were examined with 3D echocardiography and LAV was quantified during inspiratory breath hold, expiratory breath hold and during free breathing. RESULTS: Of the 100 patients, only 65 had an echocardiographic window that allowed for 3D echocardiography in the entire respiratory cycle. Mean...

  18. Comparison of Transesophageal and Transthoracic Contrast Echocardiography for Detection of a Patent Foramen Ovale

    Science.gov (United States)

    Siostrzonek, Peter; Zangeneh, Massoud; Gossinger, Heinz; Lang, Wilfried; Rosenmayr, Georg; Heinz, Gottfried; Stumpflen, Andreas; Zeiler, Karl; Schwarz, Martin; Mosslacher, Herbert

    1991-01-01

    Presence of a patent foramen ovale may indicate paradoxic embolism in patients with otherwise unexplained embolic disease. Transthoracic contrast echocardiography has been used as a simple technique for detecting patent foramen ovale. However, particularly in patients with poor transthoracic image quality, presence of a patent foramen ovale might be missed. Transesophageal contrast echocardiography provides superior visualization of the atrial septum and therefore is believed to improve diagnostic accuracy. The present study investigates the influence of image quality on the detection of a patent foramen ovale by both transthoracic and transesophageal contrast echocardiography.

  19. DOBUTAMINE STRESS-ECHOCARDIOGRAPHY: POSSIBILITY OF CLINICAL USAGE IN CARDIOLOGY PRACTICE

    Directory of Open Access Journals (Sweden)

    M. A. Saidova

    2009-01-01

    Full Text Available Currently stress-echocardiography or so-called burden echocardiography is essential method of patient examination to reveal latent ischemic heart disease (IHD. That is one of the mostly informative non-invasive methods of IHD diagnosis as well as efficacy evaluation of coronary angioplasty, surgical and pharmacological treatments of IHD. Dobutamine usage as a stress-agent at burden echocardiography allows evaluating not only ischemia but a myocardial vitality in post infarction area as well as clarify severity of valve stenosis, pulmonary hypertension and extent of latent obstruction of exhaust duct of the left ventricle. Method possibilities are presented as well as test protocol, main indications and contraindications.

  20. Usefulness of three-dimensional echocardiography in the assessment of valvular involvement in Loeffler endocarditis.

    Science.gov (United States)

    Hernandez, Carlos M; Arisha, Mohammed J; Ahmad, Amier; Oates, Ethan; Nanda, Navin C; Nanda, Anil; Wasan, Anita; Caleti, Beda E; Bernal, Cinthia L P; Gallardo, Sergio M

    2017-07-01

    Loeffler endocarditis is a complication of hypereosinophilic syndrome resulting from eosinophilic infiltration of heart tissue. We report a case of Loeffler endocarditis in which three-dimensional transthoracic and transesophageal echocardiography provided additional information to what was found by two-dimensional transthoracic echocardiography alone. Our case illustrates the usefulness of combined two- and three-dimensional echocardiography in the assessment of Loeffler endocarditis. In addition, a summary of the features of hypereosinophilic syndrome and Loeffler endocarditis is provided in tabular form. © 2017, Wiley Periodicals, Inc.

  1. Four-dimensional Map based Ni-MH battery' s SOC estimation method%基于4维Map图的镍氢电池SOC估计方法

    Institute of Scientific and Technical Information of China (English)

    胡志坤; 王文祥; 林勇; 孙岩

    2012-01-01

    A battery' s state of charge (SOC) estimation method based on the four-dimensional Map was proposed to solve the problems of current SOC estimation methods which accuracy was too low or too sensitive to data or model parameters that can not be used in practice. A Map which reflects the relation a-mong the Nickel-Metal Hydride(Ni-MH) battery's temperature, current, voltage and its SOC was established with a large number of experimental data. The approach was inspired by the finding that the adjacent charge-discharge character curves with different current, and temperature conditions are in parallel with each other within the work-interval (20% ≤Ysoc≤80% ) of the battery. Therefore, the four-dimen sional Map model of SOC, with current, temperature and voltage as its parameters, was established by interpolating in the current and temperature directions through moving the curves which is based on the relation between SOC and terminal voltage. Some experiments were conducted to verify the Map model and the result indicate that the SOC estimation error of the model is less than 3%. The SOC estimation method based on the four-dimensional Map can meet the requirements of industrial production both in accuracy and ensy realization.%针对现有镍氢电池荷电状态(SOC)估计方法因精确度太低或者对数据、模型参数要求太高而难以实用的问题,提出一种基于4维Map图的电池SOC估计方法.通过大量实验数据,建立镍氢电池SOC与温度、电流和端电压之间的基本Map图,发现在其工作区间20%≤YSOC≤80%内,不同电流、温度条件下的相邻充放电特性曲线基本相互平行.以SOC与端电压之间的关系为基础,分别在电流和温度方向上采用曲线平移的方式插值得到SOC与电流、温度、电压之间的4维Map图模型.利用试验数据进行SOC估计试验,试验结果表明,利用4维Map图模型的SOC估计误差在3%以内,基于4维Map图的

  2. 基于四维顾客价值的航空客运市场细分模型研究%Research on Market Segmentation Model of Air Passenger Transport Based on the Four-dimensional Customer Value

    Institute of Scientific and Technical Information of China (English)

    王悦; 曾小舟; 陈桥

    2015-01-01

    旨在根据航空运输行业特点以及以顾客价值为导向的市场销售特征,摒弃传统细分变量以及细分方法的使用,从Kotler四维顾客总价值角度构建航空客运市场细分模型;继而形成施测问卷,获取样本数据;将因子分析与经典的K-Means相结合,最终获得四类差距明显的子市场.研究结果表明,依据构建的市场细分模型能够获得较为满意的市场细分结果,验证了模型的有效性,可作为航空客运主体细分市场的依据之一.%According to the industry features of the civil aviation and its customer-oriented marketing characteris-tics, this paper established an efficient model of market segmentation (MS) based on Kotler's four-dimensional to-tal customer value (TCV), casting away the traditional segmentation variables and methods. On the basis of the es-tablished model, a questionnaire was formed and the correspondent data were collected. Combining the factor anal-ysis and the classic K-Means algorithm, this paper finally obtained four segmented markets with significant differ-ences. Results demonstrated that according to the constructed model, a desirable segmentation result was ac-quired, which might verify the validity of the model and thus could be the reference for MS of the operational sub-jects in civil aviation.

  3. The Effect of the Number of Simulations on the Exponents Obtained by Finite-Size Scaling Relations of the Order Parameter and the Magnetic Susceptibility for the Four-Dimensional Ising Model on the Creutz Cellular Automaton

    Science.gov (United States)

    Merdan, Z.; Güzelsoy, E.

    2012-05-01

    The four-dimensional Ising model is simulated on the Creutz cellular automaton using finite-size lattices with linear dimension 4≤ L≤8. The exponents in the finite-size scaling relations for the order parameter and the magnetic susceptibility at the finite-lattice critical temperature are computed to be β=0.49(7), β=0.49(5), β=0.50(1) and γ=1.04(4), γ=1.03(4), γ=1.02(4) for 7, 14, and 21 independent simulations, respectively. As the number of independent simulations increases, the obtained results are consistent with the renormalization group predictions of β=0.5 and γ=1. The values for the critical temperature of the infinite lattice T c (∞)=6.6788(65), T c (∞)=6.6798(69), T c (∞)=6.6802(70) are obtained from the straight-line fit of the magnetic susceptibility maxima using 4≤ L≤8 for 7, 14, and 21 independent simulations, respectively. As the number of independent simulations increases, the obtained results are in very good agreement with the series expansion results of T c (∞)=6.6817(15), T c (∞)=6.6802(2), the dynamic Monte Carlo result of T c (∞)=6.6803(1), the cluster Monte Carlo result of T c (∞)=6.680(1) and the Monte Carlo using Metropolis and Wolff-cluster algorithm result of T c (∞)=6.6802632±5×10-5.

  4. Four-dimensional spatio-temporal image correlation technology in detection of fetal heart malformation at early-second trimester%四维超声STIC技术检测中孕早期胎儿心脏畸形

    Institute of Scientific and Technical Information of China (English)

    赵艳春; 吕国荣; 李敏; 谢婧娴; 凌乐文

    2013-01-01

    目的 探讨四维超声时空关联成像(STIC)技术筛查中孕早期胎儿先天性心脏病的临床价值.方法 连续性选取70胎14~17+6周高危妊娠胎儿,先行二维超声筛查,再应用四维超声STIC技术采集胎儿心脏容积数据;由同1名超声医师采用单盲法进行分析,并将二维超声和四维超声STIC技术的诊断结果与随访结果进行比较.结果 58胎高危胎儿获得随访结果,其中心脏异常16胎,心脏正常42胎.STIC技术正确诊断率为86.21%(50/58),3胎诊断不完整,漏诊2胎,误诊3胎;二维超声正确诊断率为91.38%(53/58),1胎诊断不完整,漏诊1胎,误诊3胎;两者正确诊断率差异无统计学意义(x2 =0.78,P>0.05).四维超声STIC联合二维超声后正确诊断率96.55%(56/58),明显高于单独应用STIC技术(x2 =3.94,P<0.0S).结论 四维超声STIC技术可用于诊断中孕早期胎儿先天性心脏病;将其纳入胎儿心脏二维超声产前早期筛查,可提高正确诊断率.%Objective To investigate the clinical value of four-dimensional spatio-temporal image correlation (STIC) technology in detection of fetal congenital heart disease (CHD) at early second trimester. Methods A cross-sectional study was performed on high-risk fetuses (n=70) from 14 to 17+6 gestational age. The data of fetal heart volume were acquired with STIC, and postprocessed after routine two-dimensional ultrasonography (2D US) was performed on all fetuses. The results were analyzed by one independent examiner who was blind to the fetal outcomes. Then the prenatal diagnosis value of STIC and 2D US were evaluated according to postnatal detailed follow-up. Results A total of 58 fetuses who had detailed postnatal following-up data were included, 42 of them had normal cardiac structure, 16 were found with CHD. The accurate diagnostic rate of prenatal STIC was 86. 21% (50/58). Prenatal STIC incompletedly diagnosed 3 fetuses, missed 2 fetuses, misdiagnosed 3 fetuses. The accurate

  5. Guidelines for the provision of echocardiography in Canada: recommendations of a joint Canadian Cardiovascular Society/Canadian Society of Echocardiography Consensus Panel.

    Science.gov (United States)

    Sanfilippo, Anthony J; Bewick, David; Chan, K L; Cujec, Bibiana; Dumesnil, J G; Honos, George; Munt, Brad; Sasson, Zion; Tam, James; Tomlinson, Charles; Aboguddah, Ayman; Ahmed, Shaheeda; Ali, Mohamed; Arsenault, Marie; Ascah, Kathryn; Ashton, Tom; Baird, Michael; Basmadjian, Arsene; Beique, Francois; Blakeley, Michael; Blais, Marie-Josee; Burggraf, Gary; Burwash, Ian; Cochrane, Jessica; Fagan, Susan; Giannoccaro, Peter; Hughes, William; Jones, Alan; Jue, John; Koilpillai, Chris; Leblanc, Marie-Helene; Londry, Colleen; Morgan, Dennis; O'Reilly, Michael; Sawchuk, Corey; Siu, Samuel; Sochowski, Randy; Tremblay, Guy; Welikovitch, Lisa; Yu, Eric

    2005-07-01

    Recognizing the central role of echocardiographic examinations in the assessment of most cardiac disorders and the need to ensure the provision of these services in a highly reliable, timely, economical and safe manner, the Canadian Cardiovascular Society and Canadian Society of Echocardiography undertook a comprehensive review of all aspects influencing the provision of echocardiographic services in Canada. Five regional panels were established to develop preliminary recommendations in the five component areas, which included the echocardiographic examination, the echocardiographic laboratory and report, the physician, the sonographer and indications for examinations. Membership in the panels was structured to recognize the regional professional diversity of individuals involved in the provision of echocardiography. In addition, a focus group of cardiac sonograhers was recruited to review aspects of the document impacting on sonographer responsibilities and qualification. The document is intended to be used as a comprehensive and practical reference for all of those involved in the provision of echocardiography in Canada.

  6. Clinical utility of digital dobutamine stress echocardiography in the noninvasive evaluation of coronary artery disease.

    Science.gov (United States)

    Madu, E C; Ahmar, W; Arthur, J; Fraker, T D

    1994-05-23

    Exercise electrocardiography is an established mode of evaluation for patients with suspected coronary artery disease. It also provides prognostic information and guides therapeutic management in patients with established disease. However, some patients are unable to exercise because of orthopedic problems, neurologic diseases, peripheral vascular disease, or deconditioning. In the past, these patients have been referred for angiography to help assess their disease. Recently, however, new techniques to assess myocardial perfusion and/or function, including stress echocardiography, have been used in the noninvasive assessment of coronary artery disease in this group of patients. Echocardiography has been used in combination with different drugs, including dobutamine, dipyridamole, and adenosine. Dobutamine is probably the single most studied drug for stress echocardiography. Dobutamine stress echocardiography is a safe, feasible, and valuable technique for evaluating coronary artery disease.

  7. The role of 3D and speckle tracking echocardiography in cardiac amyloidosis: a case report.

    Science.gov (United States)

    Nucci, E M; Lisi, M; Cameli, M; Baldi, L; Puccetti, L; Mondillo, S; Favilli, R; Lunghetti, S

    2014-01-01

    Cardiac amyloidosis (CA) is a disorder characterized by amyloid fibrils deposition in cardiac interstitium; it results in a restrictive cardiomyopathy with heart failure (HF) and conduction abnormalities. The "gold standard" for diagnosis of CA is myocardial biopsy but possible sampling errors and procedural risks, limit it's use. Magnetic resonance (RMN) offers more information than traditional echocardiography and allows diagnosis of CA but often it's impossible to perform. We report the case of a man with HF and symptomatic bradyarrhythmia that required an urgent pacemaker implant. Echocardiography was strongly suggestive of CA but wasn't impossible to perform an RMN to confirm this hypothesis because the patient was implanted with a definitive pacemaker. So was performed a Speckle Tracking Echocardiography (STE) and a 3D echocardiography: STE allows to differentiate CA from others hypertrophic cardiomyopathy by longitudinal strain value eco 3D and STE for early diagnosis of CA, especially when RMN cannot be performed.

  8. Prevalence of infective endocarditis in patients with Staphylococcus aureus bacteraemia: the value of screening with echocardiography

    DEFF Research Database (Denmark)

    Rasmussen, Rasmus V; Høst, Ulla; Arpi, Magnus;

    2011-01-01

    Staphylococcus aureus infective endocarditis (IE) is a critical medical condition associated with a high morbidity and mortality. In the present study, we prospectively evaluated the importance of screening with echocardiography in an unselected S. aureus bacteraemia (SAB) population....

  9. The Role of Echocardiography in Coronary Artery Disease and Acute Myocardial Infarction

    Directory of Open Access Journals (Sweden)

    Maryam Esmaeilzadeh

    2015-10-01

    Full Text Available Echocardiography is a non-invasive diagnostic technique which provides information regarding cardiac function and hemodynamics. It is the most frequently used cardiovascular diagnostic test after electrocardiography and chest X-ray. However, in a patient with acute chest pain, Transthoracic Echocardiography is essential both for diagnosing acute coronary syndrome, zeroing on the evaluation of ventricular function and the presence of regional wall motion abnormalities, and for ruling out other etiologies of acute chest pain or dyspnea, including aortic dissection and pericardial effusion.Echocardiography is a versatile imaging modality for the management of patients with chest pain and assessment of left ventricular systolic function, diastolic function, and even myocardial and coronary perfusion and is, therefore, useful in the diagnosis and triage of patients with acute chest pain or dyspnea.This review has focused on the current applications of echocardiography in patients with coronary artery disease and myocardial infarction

  10. [Nursing care for patients undergoing pharmacological stress echocardiography: implications for clinical practice].

    Science.gov (United States)

    de Goes, Marta Georgina Oliveira; Lautert, Liana; Lucena, Amália Fátima

    2012-06-01

    The study aim was both to identify signs and symptoms previous to and during the pharmacological stress echocardiography test and to describe the nurse's role and nursing care principles for this exam. This is a descriptive study, carried out in cardiac care unit in a University Hospital in Porto Alegre, RS. Two hundred forty-six records of patients submitted to stress echocardiography were retrospectively reviewed, according to four different pharmacological schedules. The statistical comparison showed that signs and symptoms were related to the type of drug used during the exam, namely: typical angina, precordial ache, tiredness, headache and premature complexes. These results enabled a better understanding of pharmacological stress echocardiography and the instrumentalization of nurses in order to plan individualized and qualified nursing care assistance. Aside from helping develop nursing practices for the pharmacological stress echocardiography test this knowledge could also be used by nurses who carry out their activities in institutions that use this diagnostic method.

  11. Noninvasive myocardial strain measurement by speckle tracking echocardiography: validation against sonomicrometry and tagged magnetic resonance imaging

    National Research Council Canada - National Science Library

    Amundsen, Brage H; Helle-Valle, Thomas; Edvardsen, Thor; Torp, Hans; Crosby, Jonas; Lyseggen, Erik; Støylen, Asbjørn; Ihlen, Halfdan; Lima, João A C; Smiseth, Otto A; Slørdahl, Stig A

    2006-01-01

    The aim of this study was to validate speckle tracking echocardiography (STE) as a method for angle-independent measurement of regional myocardial strain, using sonomicrometry and magnetic resonance imaging (MRI...

  12. Comparison of echocardiography and angiography in determining the cause of severe aortic regurgitation.

    Science.gov (United States)

    DePace, N L; Nestico, P F; Kotler, M N; Mintz, G S; Kimbiris, D; Goel, I P; Glazier-Laskey, E E; Ross, J

    1984-01-01

    To assess the accuracy of echocardiography in determining the cause of aortic regurgitation M mode and cross sectional echocardiography were compared with angiography in 43 patients with predominant aortic regurgitation. Each patient had all three investigations performed during the same admission to hospital. In each instance, the cause of aortic regurgitation was confirmed at surgery or necropsy. Seventeen patients had rheumatic aortic valve disease, 13 bacterial endocarditis with a perforated or partially destroyed cusp, five a bicuspid aortic valve (four with a history of endocarditis), and eight aortic regurgitation secondary to aortic root dilatation or aneurysm. Overall sensitivity of echocardiography and aortography was 84% in determining the cause of aortic regurgitation. Thus, rheumatic valve disease and endocarditis appear to be the most common causes of severe aortic regurgitation in this hospital based population. Furthermore, echocardiography is a sensitive non-invasive technique for determining the cause of aortic regurgitation and allows differentiation of valvular from root causes of aortic regurgitation.

  13. Transesophageal echocardiography. 3. rev. and enl. ed.; Transoesophageale Echokardiografie. Lehrbuch und Altlas zur Untersuchungstechnik und Befundinterpretation

    Energy Technology Data Exchange (ETDEWEB)

    Lambertz, Heinz [ECHOECUCT-Akademie, Wiesbaden (Germany); Lethen, Harald (eds.) [Internistische Intensivmedizin, Wiesbaden (Germany). Innere Medizin/Kardiologie

    2013-02-01

    The book on transesophageal echocardiography covers the following issues: Development of transesophageal echocardiography, technical advances; indications and contraindication for transesophageal echocardiography; systematic of the medical examination process; cardiac valves and valve prostheses; mitral and aortic valvuloplasty, TAVI and interventional treatment of mitral regurgitation; infectious endocarditis; one-way and effluence disturbances of the left and right ventricle; diseases of the thoracic aorta; undefined right ventricle enlargement; lung embolism, acute infarct complications; TEE during anesthesia and perioperative intensive medicine, cardiac sources of embolism; cardiac tumors, mediastinal lymph nodes; pericardiac diseases; congenital heart diseases in childhood and adulthood; catheter interventions and heart valve reconstruction; surgically corrected congenital cardiac defects; intracavitary versus transesophageal echocardiography; three-dimensional TEE; coronary diagnostics; ischemia and vitality diagnostics.

  14. Retrieval of a Dislodged Catheter Using Combined Fluoroscopy and Intracardiac Echocardiography

    Directory of Open Access Journals (Sweden)

    Gus Mitsopoulos

    2015-01-01

    Full Text Available This report details a method of percutaneous, transluminal retrieval of an intracardiac foreign body using fluoroscopy in combination with intracardiac echocardiography. During retrieval, intracardiac echocardiography (ICE provided real-time anatomic localization of a constantly moving, almost radiolucent micropuncture coaxial dilator fragment with respect to the tricuspid and pulmonary valves. This method may serve as a crucial aid in retrieval of intracardiac foreign bodies that are difficult to see with fluoroscopy and which may be adjacent to cardiac valves.

  15. Mycotic aneurysm of the descending thoracic aorta: the role of transesophageal echocardiography.

    Science.gov (United States)

    Joffe, I I; Emmi, R P; Oline, J; Jacobs, L E; Owen, A N; Ioli, A; Najjar, D; Kotler, M N

    1996-01-01

    Mycotic aneurysms of the aorta are prone to rupture. Thus rapid and accurate diagnosis is essential so that surgical repair can be undertaken. We report a case of mycotic aortic aneurysm caused by mitral valve endocarditis. The aneurysm situated at the junction of the thoracoabdominal aorta was readily detected by transesophageal echocardiography. Computed tomography and aortography were complementary to transesophageal echocardiography in establishing the diagnosis. The patient underwent successful repair and acute inflammation of the aneurysm was present at histologic examination.

  16. Papillary muscle rupture caused by bacterial endocarditis: role of transesophageal echocardiography.

    Science.gov (United States)

    Habib, G; Guidon, C; Tricoire, E; Djiane, V; Monties, J R; Luccioni, R

    1994-01-01

    A 22-year-old man had severe pulmonary congestion and required mechanical ventilation. Endocarditis was suspected because a 2/6 systolic murmur was heard at the apex and because Osler nodes were present. Transthoracic and transesophageal echocardiography allowed correct diagnosis of papillary muscle rupture causing massive mitral regurgitation. To our knowledge, this is the first reported case of papillary muscle rupture caused by bacterial endocarditis diagnosed by transthoracic and transesophageal echocardiography.

  17. The potential role and limitations of echocardiography in acute respiratory distress syndrome.

    Science.gov (United States)

    Lazzeri, Chiara; Cianchi, Giovanni; Bonizzoli, Manuela; Batacchi, Stefano; Peris, Adriano; Gensini, Gian Franco

    2016-04-01

    Bedside use of Doppler echocardiography is being featured as a promising, clinically useful tool in assessing the pulmonary circulation in patients with acute respiratory distress syndrome (ARDS). The present review is aimed at summarizing the available evidence obtained with echocardiography on right ventricle (RV) function and pulmonary circulation in ARDS and to highlight the potential of this technique in clinical practice (only articles in English language were considered). According to the available evidence on echocardiographic findings, the following conclusions can be drawn: (a) echocardiography (transthoracic and transesophageal) has a growing role in the management ARDS patients mainly because of the strict interactions between the lung (and ventilation) and the RV and pulmonary circulation; (b) there may be a continuum of alterations in RV size and function and pulmonary circulation which may end in the development of acute cor pulmonale, probably paralleling ARDS disease severity; and (c) the detection of acute cor pulmonale should prompt intensivists to tailor their ventilatory strategy to the individual patient depending on the echocardiography findings. Bearing in mind the clinical role and growing importance of echocardiography in ARDS and the available evidence on this topic, we present a flow chart including the parameters to be measured and the timing of echo exams in ARDS patients. Despite the important progress that echocardiography has gained in the evaluation of patients with ARDS, several open questions remain and echocardiography still appears to be underused in these patients. A more systematic use of echocardiography (mainly through shared protocols) in ARDS could help intensivists to tailor the optimal treatment in individual patients as well as highlighting the limits and potential of this methodology in patients with ALI.

  18. ["Introduction to transthoracic, transesophageal and real time 3Dimensional transesophageal echocardiography"].

    Science.gov (United States)

    Erb, Joachim; Mukherjee, Chirojit; Knebel, Fabian; Ender, Jörg

    2014-12-01

    Echocardiography allows assessment of cardiac anatomy and function. A tailored approach to echocardiographic assessment is essential in hemodynamic unstable patients. Standard views allow comprehensive examination and also reduce the chances to oversee unexpected findings. TTE should be first choice in emergency and intensive care medicine. TEE is standard of care in intraoperative setting. 3 D echocardiography is valuable in specific situations. Written reporting of examination is mandatory.

  19. Echocardiographic Evaluation of Cardiac Function in Ischemic Rats: Value of M-Mode Echocardiography

    OpenAIRE

    Darbandi Azar, Amir; Tavakoli, Fatemeh; Moladoust, Hassan; Zare, Asghar; Sadeghpour, Anita

    2014-01-01

    Background: Echocardiography is a well-established diagnostic tool for a safe, reproducible and accurate evaluation of cardiac anatomy, hemodynamics and function in clinical practice. Objectives: We sought to demonstrate the efficacy and feasibility of M-mode echocardiography to evaluate cardiac structure and function in normal and MI-induced adult rats. Materials and Methods: All animal procedures were approved by the ethics committee of Tehran University of Medical Sciences and the investig...

  20. Doxorubicin Cardiotoxicity and Cardiac Function Improvement After Stem Cell Therapy Diagnosed by Strain Echocardiography

    OpenAIRE

    Oliveira, Maira S.; Melo, Marcos B; Carvalho, Juliana L; Melo, Isabela M; Lavor, Mario SL; Gomes, Dawidson A.; Goes, Alfredo M.; Melo, Marilia M

    2013-01-01

    Doxorubicin (Dox) is one of the most effective chemotherapeutic agents; however, it causes dose-dependent cardiotoxicity. Evaluation of left ventricular function relies on measurements based on M-mode echocardiography. A new technique based on quantification of myocardial motion and deformation, strain echocardiography, has been showed promising profile for early detection of cardiac dysfunction. Different therapy strategies, such as flavonoid plant extracts and stem cells, have been investig...

  1. Transesophageal echocardiography in the management of burn patients.

    Science.gov (United States)

    Maybauer, Marc O; Asmussen, Sven; Platts, David G; Fraser, John F; Sanfilippo, Filippo; Maybauer, Dirk M

    2014-06-01

    A systematic review was conducted to assess the level of evidence for the use of transesophageal echocardiography (TEE) in the management of burn patients. We searched any article published before and including June 30, 2013. Our search yielded 118 total publications, 11 met the inclusion criteria of burn injury and TEE. Available studies published in any language were rated and included. At the present time, there are no available systematic reviews/meta-analyses published that met our search criteria. Only a small number of clinical trials, all with a limited number of patients were available. Therefore, a meta-analysis on outcome parameters was not performed. However, the major pathologic findings in burn patients were reduced left ventricular (LV) systolic and diastolic function, mitral valve vegetation, pulmonary hypertension, pericardial effusion, fluid overload, and right heart failure. The advantages of TEE include offering direct assessment of cardiac valve competency, myocardial contractility, and most importantly real time assessment of adequacy of hemodynamic resuscitation and preload in the acute phase of resuscitation, with minimal additional risk. TEE serves multiple diagnostic purposes and is being used to better understand the fluid status and cardiac physiology of the critically ill burn patient. Randomized controlled trials especially on fluid resuscitation and cardiac performance in acute burns are warranted to potentially further improve outcome.

  2. Dobutamine Stress Echocardiography Safety in Chagas Disease Patients

    Directory of Open Access Journals (Sweden)

    Daniela do Carmo Rassi

    Full Text Available Abstract Background: A few decades ago, patients with Chagas disease were predominantly rural workers, with a low risk profile for obstructive coronary artery disease (CAD. As urbanization has increased, they became exposed to the same risk factors for CAD of uninfected individuals. Dobutamine stress echocardiography (DSE has proven to be an important tool in CAD diagnosis. Despite being a potentially arrhythmogenic method, it is safe for coronary patients without Chagas disease. For Chagas disease patients, however, the indication of DSE in clinical practice is uncertain, because of the arrhythmogenic potential of that heart disease. Objectives: To assess DSE safety in Chagas disease patients with clinical suspicion of CAD, as well as the incidence of arrhythmias and adverse events during the exam. Methods: Retrospective analysis of a database of patients referred for DSE from May/2012 to February/2015. This study assessed 205 consecutive patients with Chagas disease suspected of having CAD. All of them had their serology for Chagas disease confirmed. Results: Their mean age was 64±10 years and most patients were females (65.4%. No patient had significant adverse events, such as acute myocardial infarction, ventricular fibrillation, asystole, stroke, cardiac rupture and death. Regarding arrhythmias, ventricular extrasystoles occurred in 48% of patients, and non-sustained ventricular tachycardia in 7.3%. Conclusion: DSE proved to be safe in this population of Chagas disease patients, in which no potentially life-threatening outcome was found.

  3. Esophageal rupture: a severe complication of transesophageal echocardiography

    Directory of Open Access Journals (Sweden)

    Fernando Peixoto Ferraz de Campos

    2012-12-01

    Full Text Available Since when the first transesophageal echocardiography (TEE was undertaken in 1975, technological advances have made this diagnostic modality more reliable. TEE indications became widespread in cardiac and non-cardiac surgeries, intensive care units, and ambulatory clinics. The procedure is generally considered a safe diagnostic tool, but occasionally complications do occur. The insertion and manipulation of the ultrasound probe can cause oropharyngeal, esophageal, or gastric trauma. Although rare, these complications may present a mortality rate of up to 56% depending on the treatment approach and the elapsed time to the diagnosis. The authors report a case of a 65-year-old woman submitted to attempt a TEE in order to better study or diagnose an inter-atrial communication. After 3 days of the procedure, the patient was admitted to the hospital with edema, hyperemia of the anterior face of the neck, accompanied by systemic symptoms. The imaging diagnostic work-up evidenced signs of esophageal rupture and upper mediastinal involvement, the former confirmed by upper gastrointestinal endoscopy. The patient was treated with antibiotics and cervical and mediastinal drainage, with a favorable outcome.

  4. Soluble Suppression of Tumorigenicity 2 and Echocardiography in Sepsis.

    Science.gov (United States)

    Yang, Hyun Suk; Hur, Mina; Kim, Hanah; Magrini, Laura; Marino, Rossella; Di Somma, Salvatore

    2016-11-01

    Soluble suppression of tumorigenicity 2 (sST2) has emerged as a biomarker of cardiac stretch or remodeling, and has demonstrated a role in acutely decompensated heart failure. However, its role in sepsis-induced cardiac dysfunction is still unknown. We explored whether sST2 serum concentration reflects either systolic or diastolic dysfunction as measured by Doppler echocardiography. In a total of 127 patients with sepsis, correlations between sST2 and blood pressure, left ventricular (LV) ejection fraction, LV diastolic filling (ratio of early transmitral flow velocity to early diastolic mitral annulus velocity), and resting pulmonary arterial pressure were evaluated. Correlations between sST2 and other sepsis biomarkers (high-sensitivity C-reactive protein [hs-CRP] and procalcitonin) were also examined. sST2 showed a moderate correlation with mean arterial pressure (r=-0.3499) but no correlation with LV ejection fraction, diastolic filling, or resting pulmonary hypertension. It showed moderate correlations with hs-CRP and procalcitonin (r=0.2608 and r=0.3829, respectively). sST2 might have a role as a biomarker of shock or inflammation, but it cannot reflect echocardiographic findings of LV ejection fraction or diastolic filling in sepsis.

  5. COMPARISON OF CARDIAC BIOMARKERS AND ECHOCARDIOGRAPHY IN DIAGNOSING MYOCARDITIS

    Directory of Open Access Journals (Sweden)

    Nimi Bharathan

    2017-03-01

    Full Text Available BACKGROUND Conventional methods used to diagnose or rule out myocarditis is not useful in detecting cardiac myocyte injury in clinically suspected cases. Endomyocardial biopsy and histopathological examination is not feasible in most government hospitals in India. Sensitive parameters have yet to be found out. The study was conducted to find out whether diagnosis of myocarditis in clinically suspected cases can be done by measurement of serum levels of cardiac troponinI (cTnI and MB isoform of creatine kinase (CK-MB. MATERIALS AND METHODS 19 patients with clinically suspected myocarditis were screened for CK-MB activity and cTnI. Echocardiography, ECG and IgM for leptospirosis were also checked in these patients. RESULTS cTnI was elevated in 10 out of 19 patients with clinically suspected myocarditis. CK-MB was elevated in 7 patients. CONCLUSION Elevation of cTnI level in blood can be taken as an indicator of cardiac muscle cell injury in suspected cases of myocarditis.

  6. Complications during pharmacological stress echocardiography: a video-case series

    Directory of Open Access Journals (Sweden)

    Bigi Riccardo

    2005-09-01

    Full Text Available Abstract Background Stress echocardiography is a cost-effective tool for the modern noninvasive diagnosis of coronary artery disease. Several physical and pharmacological stresses are used in combination with echocardiographic imaging, usually exercise, dobutamine and dipyridamole. The safety of a stress is (or should be a major determinant in the choice of testing. Although large scale single center experiences and multicenter trial information are available for both dobutamine and dipyridamole stress echo testing, complications or side effects still can occur even in the most experienced laboratories with the most skilled operators. Case presentation We decided to present a case collection of severe complications during pharmacological stress echo testing, including a ventricular tachycardia, cardiogenic shock, transient ischemic attack, torsade de pointe, fatal ventricular fibrillation, and free wall rupture. Conclusion We believe that, in this field, every past complication described is a future complication avoided; what happens in your lab is more true of what you read in journals; and Good Clinical Practice is not "not having complications", but to describe the complications you had.

  7. Dobutamine Stress Echocardiography Safety in Chagas Disease Patients

    Science.gov (United States)

    Rassi, Daniela do Carmo; Vieira, Marcelo Luiz Campos; Furtado, Rogerio Gomes; Turco, Fabio de Paula; Melato, Luciano Henrique; Hotta, Viviane Tiemi; Nunes, Colandy Godoy de Oliveira; Rassi Jr., Luiz; Rassi, Salvador

    2017-01-01

    Background A few decades ago, patients with Chagas disease were predominantly rural workers, with a low risk profile for obstructive coronary artery disease (CAD). As urbanization has increased, they became exposed to the same risk factors for CAD of uninfected individuals. Dobutamine stress echocardiography (DSE) has proven to be an important tool in CAD diagnosis. Despite being a potentially arrhythmogenic method, it is safe for coronary patients without Chagas disease. For Chagas disease patients, however, the indication of DSE in clinical practice is uncertain, because of the arrhythmogenic potential of that heart disease. Objectives To assess DSE safety in Chagas disease patients with clinical suspicion of CAD, as well as the incidence of arrhythmias and adverse events during the exam. Methods Retrospective analysis of a database of patients referred for DSE from May/2012 to February/2015. This study assessed 205 consecutive patients with Chagas disease suspected of having CAD. All of them had their serology for Chagas disease confirmed. Results Their mean age was 64±10 years and most patients were females (65.4%). No patient had significant adverse events, such as acute myocardial infarction, ventricular fibrillation, asystole, stroke, cardiac rupture and death. Regarding arrhythmias, ventricular extrasystoles occurred in 48% of patients, and non-sustained ventricular tachycardia in 7.3%. Conclusion DSE proved to be safe in this population of Chagas disease patients, in which no potentially life-threatening outcome was found. PMID:28099588

  8. Augmented reality simulator for training in two-dimensional echocardiography.

    Science.gov (United States)

    Weidenbach, M; Wick, C; Pieper, S; Quast, K J; Fox, T; Grunst, G; Redel, D A

    2000-02-01

    In two-dimensional echocardiography the sonographer must synthesize multiple tomographic slices into a mental three-dimensional (3D) model of the heart. Computer graphics and virtual reality environments are ideal to visualize complex 3D spatial relationships. In augmented reality (AR) applications, real and virtual image data are linked, to increase the information content. In the presented AR simulator a 3D surface model of the human heart is linked with echocardiographic volume data sets. The 3D echocardiographic data sets are registered with the heart model to establish spatial and temporal congruence. The heart model, together with an animated ultrasound sector represents a reference scenario, which displays the currently selected two-dimensional echocardiographic cutting plane calculated from the volume data set. Modifications of the cutting plane within the echocardiographic data are transferred and visualized simultaneously and in real time within the reference scenario. The trainee can interactively explore the 3D heart model and the registered 3D echocardiographic data sets by an animated ultrasound probe, whose position is controlled by an electromagnetic tracking system. The tracking system is attached to a dummy transducer and placed on a plastic puppet to give a realistic impression of a two-dimensional echocardiographic examination.

  9. The Preoperative Evaluation of Infective Endocarditis via 3-Dimensional Transesophageal Echocardiography.

    Science.gov (United States)

    Yong, Matthew S; Saxena, Pankaj; Killu, Ammar M; Coffey, Sean; Burkhart, Harold M; Wan, Siu-Hin; Malouf, Joseph F

    2015-08-01

    Transesophageal echocardiography continues to have a central role in the diagnosis of infective endocarditis and its sequelae. Recent technological advances offer the option of 3-dimensional imaging in the evaluation of patients with infective endocarditis. We present an illustrative case and review the literature regarding the potential advantages and limitations of 3-dimensional transesophageal echocardiography in the diagnosis of complicated infective endocarditis. A 51-year-old man, an intravenous drug user who had undergone bioprosthetic aortic valve replacement 5 months earlier, presented with prosthetic valve endocarditis. Preoperative transesophageal echocardiography with 3D rendition revealed a large abscess involving the mitral aortic intervalvular fibrosa, together with a mycotic aneurysm that had ruptured into the left atrium, resulting in a left ventricle-to-left atrium fistula. Three-dimensional transesophageal echocardiography enabled superior preoperative anatomic delineation and surgical planning. We conclude that 3-dimensional transesophageal echocardiography can be a useful adjunct to traditional 2-dimensional transesophageal echocardiography as a tool in the diagnosis of infective endocarditis.

  10. Teles-operated echocardiography using a robotic arm and an internet connection.

    Science.gov (United States)

    Arbeille, Philippe; Provost, Romain; Zuj, Kathryn; Dimouro, Dominique; Georgescu, Monica

    2014-10-01

    The objective was to design and validate a method of tele-operated echocardiography. The method was tested in a hospital facility with an expert sonographer located in a room 10 m away from the patient. An ultrasound probe, fixed to a motorized probe holder, was located on the patient by a non-sonographer and was remotely controlled by the expert sonographer via an Internet connection. Scans were performed on 41 cardiac patients. The quality of the cardiac views obtained using tele-echocardiography was lower than that of reference echocardiography, but generated similar measurements in 93%-100% of the cases. Bland-Altman plots and statistical comparison of tele- and reference echocardiography measures revealed no differences (p > 0.05). Of the 71 valve leaks or aortic stenoses present, 61 (86%) were detected using tele-echocardiography. These results indicate that tele-echocardiography provided reliable diagnoses and acceptable measurements in 86% and 93% of cases, respectively, with no false-positive diagnoses being reported. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  11. Thromboembolism Prevention via Transcatheter Left Atrial Appendage Closure with Transeosophageal Echocardiography Guidance

    Directory of Open Access Journals (Sweden)

    John Palios

    2014-01-01

    Full Text Available Atrial fibrillation (AF is an independent risk factor for stroke. Anticoagulation therapy has a risk of intracerebral hemorrhage. The use of percutaneous left atrial appendage (LAA closure devices is an alternative to anticoagulation therapy. Echocardiography has a leading role in LAA closure procedure in patient selection, during the procedure and during followup. A comprehensive echocardiography study is necessary preprocedural in order to identify all the lobes of the LAA, evaluate the size of the LAA ostium, look for thrombus or spontaneous echo contrast, and evaluate atrial anatomy, including atrial septal defect and patent foramen ovale. Echocardiography is used to identify potential cardiac sources of embolism, such as atrial septal aneurysm, mitral valve disease, and aortic debris. During the LAA occlusion procedure transeosophageal echocardiography provides guidance for the transeptal puncture and monitoring during the release of the closure device. Procedure-related complications can be evaluated and acceptable device release criteria such as proper position and seating of the occluder in the LAA, compression, and stability can be assessed. Postprocedural echocardiography is used for followup to assess the closure of the LAA ostium. This overview paper describes the emerging role of LAA occlusion procedure with transeosophageal echocardiography guidance as an alternative to anticoagulation therapy in patients with AF.

  12. [Value and indications of transesophageal echocardiography before cardioversion of atrial fibrillation].

    Science.gov (United States)

    Lesbre, J P

    2003-09-01

    Transoesophageal echocardiography is essential for the diagnosis of left atrial thrombosis and its precursors (dense spontaneous contrast--reduced auricular emptying velocities) and for the diagnosis of complex aortic atheroma. The sensitivity and specificity of transoesophageal echocardiography for the diagnosis of left atrial thrombus are about 100% and about 90% for that of aortic atheroma. The formal indications for transoesophageal echocardiography before cardioversion are: atrial fibrillation complicated by stroke or a recent systemic embolism: atrial fibrillation complicated by mitral valve disease as the thrombo-embolic risk is major in this context: atrial fibrillation with a high thromboembolic risk: a history of stroke, presence of cardiac failure, diabetes, permanent hypertension, a very dilated left atrium (> or = 50 mm): apparently isolated atrial fibrillation for which long term anticoagulant therapy is hoped to be avoided. On the other hand, in recent, uncomplicated, non-valvular atrial fibrillation, a common fallacy should be corrected: transoesophageal echocardiography does not improve the safety of electrical cardioversion. With similar durations of prior anticoagulant therapy. Over a 3 week period, the frequency of thromboembolic complications is the same whether or not transoesophageal echocardiography is performed before cardioversion (0.8% in both groups of the SEIDL study). With short periods of anticoagulant therapy before cardioversion, there is a higher thromboembolic complication and mortality rate (ACUTE study). The safety of cardioversion is not related to the practice of prior transoesophageal echocardiography but to strict and efficacious anticoagulation for a period of 3 weeks before cardioversion.

  13. Detecting depressive and anxiety disorders in distressed patients in primary care; comparative diagnostic accuracy of the Four-Dimensional Symptom Questionnaire (4DSQ and the Hospital Anxiety and Depression Scale (HADS

    Directory of Open Access Journals (Sweden)

    Verhaak Peter FM

    2009-08-01

    Full Text Available Abstract Background Depressive and anxiety disorders often go unrecognized in distressed primary care patients, despite the overtly psychosocial nature of their demand for help. This is especially problematic in more severe disorders needing specific treatment (e.g. antidepressant pharmacotherapy or specialized cognitive behavioural therapy. The use of a screening tool to detect (more severe depressive and anxiety disorders may be useful not to overlook such disorders. We examined the accuracy with which the Four-Dimensional Symptom Questionnaire (4DSQ and the Hospital Anxiety and Depression Scale (HADS are able to detect (more severe depressive and anxiety disorders in distressed patients, and which cut-off points should be used. Methods Seventy general practitioners (GPs included 295 patients on sick leave due to psychological problems. They excluded patients with recognized depressive or anxiety disorders. Patients completed the 4DSQ and HADS. Standardized diagnoses of DSM-IV defined depressive and anxiety disorders were established with the Composite International Diagnostic Interview (CIDI. Receiver Operating Characteristic (ROC analyses were performed to obtain sensitivity and specificity values for a range of scores, and area under the curve (AUC values as a measure of diagnostic accuracy. Results With respect to the detection of any depressive or anxiety disorder (180 patients, 61%, the 4DSQ and HADS scales yielded comparable results with AUC values between 0.745 and 0.815. Also with respect to the detection of moderate or severe depressive disorder, the 4DSQ and HADS depression scales performed comparably (AUC 0.780 and 0.739, p 0.165. With respect to the detection of panic disorder, agoraphobia and social phobia, the 4DSQ anxiety scale performed significantly better than the HADS anxiety scale (AUC 0.852 versus 0.757, p 0.001. The recommended cut-off points of both HADS scales appeared to be too low while those of the 4DSQ anxiety

  14. Three-dimensional echocardiography in congenital heart disease : an expert consensus document from the European Association of Cardiovascular Imaging and the American Society of Echocardiography

    NARCIS (Netherlands)

    Simpson, John; Lopez, Leo; Acar, Philippe; Friedberg, Mark; Khoo, Nee; Ko, Helen; Marek, Jan; Marx, Gerald; McGhie, Jackie; Meijboom, Folkert|info:eu-repo/dai/nl/136537367; Roberson, David; Van den Bosch, Annemien; Miller, Owen; Shirali, Girish

    2016-01-01

    Three-dimensional echocardiography (3DE) has become important in the management of patients with congenital heart disease (CHD), particularly with pre-surgical planning, guidance of catheter intervention, and functional assessment of the heart. 3DE is increasingly used in children because of good

  15. Three-dimensional Echocardiography in Congenital Heart Disease : An Expert Consensus Document from the European Association of Cardiovascular Imaging and the American Society of Echocardiography

    NARCIS (Netherlands)

    Simpson, John; Lopez, Leo; Acar, Philippe; Friedberg, Mark K; Khoo, Nee S; Ko, Helen; Marek, Jan; Marx, Gerald; McGhie, Jackie S; Meijboom, Folkert|info:eu-repo/dai/nl/136537367; Roberson, David; van den Bosch, Annemien E; Miller, Owen; Shirali, Girish

    2017-01-01

    Three-dimensional echocardiography (3DE) has become important in the management of patients with congenital heart disease (CHD), particularly with pre-surgical planning, guidance of catheter intervention, and functional assessment of the heart. 3DE is increasingly used in children because of good

  16. Three-dimensional Echocardiography in Congenital Heart Disease : An Expert Consensus Document from the European Association of Cardiovascular Imaging and the American Society of Echocardiography

    NARCIS (Netherlands)

    Simpson, John; Lopez, Leo; Acar, Philippe; Friedberg, Mark K; Khoo, Nee S; Ko, Helen; Marek, Jan; Marx, Gerald; McGhie, Jackie S; Meijboom, Folkert; Roberson, David; van den Bosch, Annemien E; Miller, Owen; Shirali, Girish

    2017-01-01

    Three-dimensional echocardiography (3DE) has become important in the management of patients with congenital heart disease (CHD), particularly with pre-surgical planning, guidance of catheter intervention, and functional assessment of the heart. 3DE is increasingly used in children because of good ac

  17. Three-dimensional echocardiography in congenital heart disease : an expert consensus document from the European Association of Cardiovascular Imaging and the American Society of Echocardiography

    NARCIS (Netherlands)

    Simpson, John; Lopez, Leo; Acar, Philippe; Friedberg, Mark; Khoo, Nee; Ko, Helen; Marek, Jan; Marx, Gerald; McGhie, Jackie; Meijboom, Folkert|info:eu-repo/dai/nl/136537367; Roberson, David; Van den Bosch, Annemien; Miller, Owen; Shirali, Girish

    2016-01-01

    Three-dimensional echocardiography (3DE) has become important in the management of patients with congenital heart disease (CHD), particularly with pre-surgical planning, guidance of catheter intervention, and functional assessment of the heart. 3DE is increasingly used in children because of good ac

  18. Three-dimensional echocardiography in congenital heart disease : an expert consensus document from the European Association of Cardiovascular Imaging and the American Society of Echocardiography

    NARCIS (Netherlands)

    Simpson, John; Lopez, Leo; Acar, Philippe; Friedberg, Mark; Khoo, Nee; Ko, Helen; Marek, Jan; Marx, Gerald; McGhie, Jackie; Meijboom, Folkert; Roberson, David; Van den Bosch, Annemien; Miller, Owen; Shirali, Girish

    2016-01-01

    Three-dimensional echocardiography (3DE) has become important in the management of patients with congenital heart disease (CHD), particularly with pre-surgical planning, guidance of catheter intervention, and functional assessment of the heart. 3DE is increasingly used in children because of good ac

  19. Assessment of Myocardial Perfusion and Systolic Function in Patients with Coronary Artery Disease after Coronary Artery Bypass Surgery by Myocardial Contrast Echocardiography and Two-dimensional Strain Echocardiography

    Institute of Scientific and Technical Information of China (English)

    Rong LIU; Youbin DENG; Xiaojun BI; Yani LIU; Li XIONG; Liuping CHEN

    2009-01-01

    The clinically applied value of myocardial perfusion and systolic function in patients with coronary artery disease after coronary artery bypass surgery using real-time myocardial contrast echo-cardiography (RT-MCE) combined with two-dimensional strain echocardiography was assessed.Twenty patients underwent intravenous RT-MCE by intravenous injections of Sono Vue before and after coronary artery bypass surgery. Two-dimensional images were recorded from the left ventricular four-chamber view, two-chamber view and the apical view before, and two weeks and three months af-ter coronary artery bypass surgery, and the peak systolic longitudinal strain was measured. The results showed that myocardial perfusion was significantly increased after coronary artery bypass surgery in about 71.6% segments. In the group that myocardial perfusion was improved, the peak systolic longitu-dinal strain three months after bypass surgery was significantly higher than that before operation [(-15.78±5.91)% vs (-10.45±8.31)%, P0.05]. It was con-cluded that whether or not the improvement of myocardial perfusion can mirror the recovery trend of regional systolic function, two-dimensional strain echocardiography can observe dynamic change of re-gional systolic function. The combination of myocardial perfusion with two-dimensional strain echocar-diography can more accurately assess the curative effectiveness of coronary artery bypass surgery.

  20. Cancer therapy and cardiotoxicity: The need of serial Doppler echocardiography

    Directory of Open Access Journals (Sweden)

    Pardo Moira

    2007-01-01

    Full Text Available Abstract Cancer therapy has shown terrific progress leading to important reduction of morbidity and mortality of several kinds of cancer. The therapeutic management of oncologic patients includes combinations of drugs, radiation therapy and surgery. Many of these therapies produce adverse cardiovascular complications which may negatively affect both the quality of life and the prognosis. For several years the most common noninvasive method of monitoring cardiotoxicity has been represented by radionuclide ventriculography while other tests as effort EKG and stress myocardial perfusion imaging may detect ischemic complications, and 24-hour Holter monitoring unmask suspected arrhythmias. Also biomarkers such as troponine I and T and B-type natriuretic peptide may be useful for early detection of cardiotoxicity. Today, the widely used non-invasive method of monitoring cardiotoxicity of cancer therapy is, however, represented by Doppler-echocardiography which allows to identify the main forms of cardiac complications of cancer therapy: left ventricular (systolic and diastolic dysfunction, valve heart disease, pericarditis and pericardial effusion, carotid artery lesions. Advanced ultrasound tools, as Integrated Backscatter and Tissue Doppler, but also simple ultrasound detection of "lung comet" on the anterior and lateral chest can be helpful for early, subclinical diagnosis of cardiac involvement. Serial Doppler echocardiographic evaluation has to be encouraged in the oncologic patients, before, during and even late after therapy completion. This is crucial when using anthracyclines, which have early but, most importantly, late, cumulative cardiac toxicity. The echocardiographic monitoring appears even indispensable after radiation therapy, whose detrimental effects may appear several years after the end of irradiation.

  1. An Experimental Study of Myocardial Viability with Myocardial Contrast Echocardiography

    Institute of Scientific and Technical Information of China (English)

    张稳柱; 查道刚; 成官迅; 杨绍青; 刘伊丽

    2001-01-01

    Background Myocardial blood flow(MBF) can be quantified with myocardial contrast echocardiography (MCE) during a venous in fusion of microbubble. A minimal MBF is required to maintain cell membrane integrity and myocardial viability in ischemic condition. Thus, we hypothesized that MCE could be used to assess myocardial viability by the determination of MBF. Methods and Results MCE was performed at 4 hours after ligation of proximal left anterior descending coronary artery in 7dogs with constant venous infusions of microbubbles.The video intensity versus pulsing interval plots derived from each myocardial pixel were fitted to an exponential function: y=A(1-e-βt), where y is Ⅵ at pulsing interval t, A reflects rnicrovascular cross- sectional area (or myocardial blood volume), and β reflects mean myocardial microbubble velocity. The product of A · β represents MBF. MBF was also obtained by radiolabeled microsphere method servered as reference.MBF derived by radiolabeled microsphere- method in the regions of normal, ischemia and infarction was 1.5±0.3, 0.7±0.3, 0.3±0.2mL·min-1· g-1respectively. The product of A · β obtained by MCE in those regions was 52. 46 ± 15.09, 24.36 ± 3.89, 3.74± ± 3.80 respectively. There was good correlation between normalized MBF and the normalized A · β (r =0. 81, P = 0. 001 ). Conclusions MCE has an ability to determine myocardial viability in myocardial in farction canine model.

  2. Improving on the diagnostic characteristics of echocardiography for pulmonary hypertension.

    Science.gov (United States)

    Broderick-Forsgren, Kathleen; Davenport, Clemontina A; Sivak, Joseph A; Hargett, Charles William; Foster, Michael C; Monteagudo, Andrew; Armour, Alicia; Rajagopal, Sudarshan; Arges, Kristine; Velazquez, Eric J; Samad, Zainab

    2017-09-01

    This retrospective study evaluated the diagnostic characteristics of a combination of echocardiographic parameters for pulmonary hypertension (PH). Right ventricular systolic pressure (RVSP) estimation by echocardiography (echo) is used to screen for PH. However, the sensitivity of this method is suboptimal. We hypothesized that RVSP estimation in conjunction with other echo parameters would improve the value of echo for PH. The Duke Echo database was queried for adult patients with known or suspected PH who had undergone both echo and right heart catheterization (RHC) within a 24 h period between 1/1/2008 and 12/31/2013. Patients with complex congenital heart disease, heart transplantation, ventricular assist device, or on mechanical ventilation at time of study were excluded. Diagnostic characteristics of several echo parameters (right atrial enlargement, pulmonary artery (PA) enlargement, RV enlargement, RV dysfunction, and RVSP) for PH (mean PA pressure 25 mmHg on RHC) were evaluated among 1007 patients. RVSP ≥40 had a sensitivity of 77% (accuracy 77), while RVSP ≥35 had the highest sensitivity at 88% (81% accuracy). PA enlargement had the lowest sensitivity at 17%. The area under the curve (AUC) for RVSP was 0.844. A model including RVSP, RA, PA, RV enlargement and RV dysfunction had a higher AUC (AUC = 0.87) than RVSP alone. The value of echo as a screening test for PH is improved by a model incorporating a lower RVSP in addition to other right heart parameters. These findings need to be validated in prospective cohorts.

  3. [Multiplane transesophageal echocardiography for the monitoring of cardiac surgery].

    Science.gov (United States)

    Pepi, M; Barbier, P; Doria, E; Tamborini, G; Berti, M; Muratori, M; Guazzi, M; Maltagliati, A; Alimento, M; Celeste, F

    1994-08-01

    Multiplane transesophageal echocardiography (TEE) allows visualization of the heart and great vessels through an infinite number of imaging planes and improves the diagnostic capabilities of mono and biplane TEE. This study was undertaken to test whether MTEE is a useful intraoperative monitoring method during cardiac surgery. Intraoperative multiplane TEE was performed in 200 patients (mean age 56 +/- 19 years) as a part of the routine clinical care. We systematically acquired cardiac images from the gastric fundus (short and long axes of the ventricles), lower esophagus (four-chamber, two-chamber, and long axis), upper esophagus (13 views concerning the aorta, pulmonary artery, left and right atrium, systemic and pulmonary veins, coronary arteries, right ventricular outflow tract), and searched for complete views of the thoracic descending aorta. All views analyzed in the preoperative (immediately before cardiopulmonary bypass), intraoperative and postoperative phases evaluating: the angle between current and 0 degree at which each view was obtained; the success rate of each view; the usefulness of the different views in providing essential additional clinical information compared to 0 degrees and 90 degrees of the traditional biplane TEE. Most views of the heart and great vessels were visualized in oblique planes, and other views were significantly improved thanks to slight angle corrections. Multiplane TEE was particularly useful in the preoperative and postoperative phases of aortic dissection (11 cases), mitral valve repair (13 cases), left ventricular aneurysmectomy (9 cases), right atrial thrombosis (1 case), positioning of left ventricular hemopump (2 cases), mitral-aortic endocarditis (3 cases), bleeding from proximal suture of an aortic heterograft (1 case).(ABSTRACT TRUNCATED AT 250 WORDS)

  4. Live three-dimensional transesophageal echocardiography in mitral valve surgery

    Institute of Scientific and Technical Information of China (English)

    MA Ning; LI Zhi-an; MENG Xu; YANG Ya

    2008-01-01

    Background Live three-dimensional transesophageal echocardiography (live-3D-TEE) is a new technique, but its clinical value is unclear at present. This study aimed to investigate the feasibility, imaging quality and accuracy of live-3D-TEE for assessing mitral valve morphology to determine if live-3D-TEE has important value in mitral valve surgery.Methods Twenty-four patients with mitral valve disease (mean age (47.1 rdiography (2D-TEE) before and after mitral valve surgery. Sensitivity, specificity, and total consistency rates of live-3D-TEE for diagnosing ruptured chordae were calculated and compared to surgeon's findings. We also compared the diagnostic accuracy of mitral valve disease between live-3D-TEE and 2D-TEE.Results Live-3D-TEE allowed visualization of the anatomic structure of the heart online and clearly identified the valvular apparatus and their defects. Sensitivity and specificity for the detection of ruptured chordae by live-3D-TEE were 87.5% and 100% respectively, and the total consistency rate was 95.8%. Additional defects not diagnosted by 2D-TEE were found in three cases (12.5%) preoperatively by live-3D-TEE. Live-3D-TEE could evaluate the function of prosthetic or native valves immediately after operation. One case was re-repaired (4.2%) using guidance by live-3D-TEE. Conclusion Live-3D-TEE enabled evaluation of mitral valve function and provided adequate valuable information before and after mitral valve surgery. We conclude that live-3D-TEE can play an important role in mitral valve surgery.

  5. Student tutors for hands-on training in focused emergency echocardiography – a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Kühl Matthias

    2012-10-01

    Full Text Available Abstract Background Focused emergency echocardiography performed by non-cardiologists has been shown to be feasible and effective in emergency situations. During resuscitation a short focused emergency echocardiography has been shown to narrow down potential differential diagnoses and to improve patient survival. Quite a large proportion of physicians are eligible to learn focused emergency echocardiography. Training in focused emergency echocardiography usually comprises a lecture, hands-on trainings in very small groups, and a practice phase. There is a shortage of experienced echocardiographers who can supervise the second step, the hands-on training. We thus investigated whether student tutors can perform the hands-on training for focused emergency echocardiography. Methods A total of 30 volunteer 4th and 5th year students were randomly assigned to a twelve-hour basic echocardiography course comprising a lecture followed by a hands-on training in small groups taught either by an expert cardiographer (EC or by a student tutor (ST. Using a pre-post-design, the students were evaluated by an OSCE. The students had to generate two still frames with the apical five-chamber view and the parasternal long axis in five minutes and to correctly mark twelve anatomical cardiac structures. Two blinded expert cardiographers rated the students’ performance using a standardized checklist. Students could achieve a maximum of 25 points. Results Both groups showed significant improvement after the training (p Conclusions Hands-on training by student tutors led to a significant gain in echocardiography skills, although inferior to teaching by an expert cardiographer.

  6. Physical Stress Echocardiography: Prediction of Mortality and Cardiac Events in Patients with Exercise Test showing Ischemia

    Directory of Open Access Journals (Sweden)

    Ana Carla Pereira de Araujo

    2014-11-01

    Full Text Available Background: Studies have demonstrated the diagnostic accuracy and prognostic value of physical stress echocardiography in coronary artery disease. However, the prediction of mortality and major cardiac events in patients with exercise test positive for myocardial ischemia is limited. Objective: To evaluate the effectiveness of physical stress echocardiography in the prediction of mortality and major cardiac events in patients with exercise test positive for myocardial ischemia. Methods: This is a retrospective cohort in which 866 consecutive patients with exercise test positive for myocardial ischemia, and who underwent physical stress echocardiography were studied. Patients were divided into two groups: with physical stress echocardiography negative (G1 or positive (G2 for myocardial ischemia. The endpoints analyzed were all-cause mortality and major cardiac events, defined as cardiac death and non-fatal acute myocardial infarction. Results: G2 comprised 205 patients (23.7%. During the mean 85.6 ± 15.0-month follow-up, there were 26 deaths, of which six were cardiac deaths, and 25 non-fatal myocardial infarction cases. The independent predictors of mortality were: age, diabetes mellitus, and positive physical stress echocardiography (hazard ratio: 2.69; 95% confidence interval: 1.20 - 6.01; p = 0.016. The independent predictors of major cardiac events were: age, previous coronary artery disease, positive physical stress echocardiography (hazard ratio: 2.75; 95% confidence interval: 1.15 - 6.53; p = 0.022 and absence of a 10% increase in ejection fraction. All-cause mortality and the incidence of major cardiac events were significantly higher in G2 (p < 0. 001 and p = 0.001, respectively. Conclusion: Physical stress echocardiography provides additional prognostic information in patients with exercise test positive for myocardial ischemia.

  7. Exercise echocardiography and multidetector computed tomography for the evaluation of acute chest pain.

    Science.gov (United States)

    Mas-Stachurska, Aleksandra; Miró, Oscar; Sitges, Marta; de Caralt, Teresa M; Perea, Rosario J; López, Beatriz; Sánchez, Miquel; Paré, Carles; Bosch, Xavier; Ortiz-Pérez, José T

    2015-01-01

    Up to 4% of patients with acute chest pain, normal electrocardiogram, and negative troponins present major adverse cardiac events as a result of undiagnosed acute coronary syndrome. Our aim was to compare the diagnostic performance of multidetector computed tomography and exercise echocardiography in patients with a low-to-intermediate probability of coronary artery disease. We prospectively included 69 patients with acute chest pain, normal electrocardiogram, and negative troponins who underwent coronary tomography angiography and exercise echocardiography. Patients with coronary stenosis ≥ 50% or Agatston calcium score ≥ 400 on coronary tomography angiography or positive exercise echocardiography, or with inconclusive results, were admitted to rule out acute coronary syndrome. An acute coronary syndrome was confirmed in 17 patients (24.6%). This was lower than the suspected 42% based on coronary tomography angiography (P<.05) and not significantly different than the suspected 29% based on the results of exercise echocardiography (P=.56). Exercise echocardiography was normal in up to 37% of patients with pathological findings on coronary tomography angiography. The latter technique provided a higher sensitivity (100% vs 82.3%; P=.21) but lower specificity (76.9% vs 88.4%; P=.12) than exercise echocardiography for the diagnosis of acute coronary syndrome, although without reaching statistical significance. Increasing the stenosis cutoff point to 70% increased the specificity of coronary tomography angiography to 88.4%, while maintaining high sensitivity. Coronary tomography angiography offers a valid alternative to exercise echocardiography for the diagnosis of acute coronary syndrome among patients with low-to-intermediate probability of coronary artery disease. A combination of both techniques could improve the diagnosis of acute coronary syndrome. Copyright © 2014 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

  8. Modern Use of Echocardiography in Transcatheter Aortic Valve Replacement: an Up-Date.

    Science.gov (United States)

    Caldararu, Cristina; Balanescu, Serban

    2016-12-01

    Echocardiography is the cornerstone in the diagnosis of any valvular heart disease. The accurate diagnosis of aortic stenosis, the left ventricle function and the other heart valves evaluation are currently done by ultrasound alone. Prosthetic valve choice and dimensions prior to implantation can be done solely by proper use of echocardiography. The emergence of new methods to cure aortic stenosis such as trans-catheter aortic valve replacement (TAVR) emphasized the diagnostic value of cardiac ultrasound. The usefulness of echocardiography in TAVR can be divided in the baseline assessment (common to patients treated by conventional surgery), intra-procedural guidance of valve deployment and post-procedural follow-up. In the baseline diagnostic work-up echocardiography should allow proper assessment of low-gradient severe aortic stenosis and especially of "low-flow, low-gradient" aortic stenosis, as far the benefit of any valve intervention in these cases may be overshadowed by persistent ventricular dysfunction. "Classic" TAVR is performed with a trans-esophageal echocardiography probe in place, but recently intracardiac echocardiography (ICE) was advocated to reduce the need for general anesthesia. "Minimalist TAVR approach" recommends no echo-guidance and valve implantation by angiography alone. Post-TAVR echo assessment should allow prompt recognition of early complications and the severity of para-valvular leaks. Long term follow-up by echocardiography assesses prosthetic valve function, left ventricular functional recovery and the impact of the procedure on associated conditions (mitral regurgitation, pulmonary hypertension or tricuspid regurgitation). This article emphasizes the role of the cardiologist with ultrasound skills in the assessment of patients addressed to TAVR.

  9. Analysis of the Effect of the Application of Four-dimensional Color Doppler Ultrasound in Prenatal Screening of Fetal Malformation%产前胎儿畸形筛查中四维彩超的应用效果分析

    Institute of Scientific and Technical Information of China (English)

    纪亚梅; 王文俊

    2016-01-01

    目的:探讨产前胎儿畸形筛查中四维彩超的应用效果。方法方便选取2013年1月—2016年2月在该院进行产前筛查的2200例中晚期孕妇作为研究对象,分别对其进行二维彩超及四维彩超检查,根据胎儿出生后情况或引产结果对二维彩超及四维彩超的检出率进行比较。结果二维彩超对胎儿畸形的检出率为76.92%(40/52),四维彩超对胎儿畸形的检出率为96.15%(50/52),四维彩超对胎儿畸形的检出率明显高于二维彩超(P﹤0.01)。结论与二维彩超相比,四维彩超在胎儿畸形检出方面具有明显优势,值得临床推广应用。%Objective To investigate the application effect of four dimensional color Doppler ultrasound in prenatal screen-ing of fetal malformation. Methods 2 200 cases of advanced pregnant women from January 2013 to February 2016 in our hospital were selected as research subjects. Two dimensional color Doppler ultrasound and four-dimensional color Doppler ultrasound examination were carried out on them. According to the results of the fetus after birth or induction of labor, the detection rate of two-dimensional color Doppler ultrasound and four-dimensional color Doppler ultrasound were compared. Results The detection rate of two-dimensional color Doppler ultrasound for fetal malformation was 76.92%(40/52), while that of four-dimensional color Doppler ultrasound was 96.15%(50/52). Thus the detection rate of four-dimensional color Doppler ultrasound was obviously higher than that of two-dimensional color Doppler ultrasound(P﹤0.01). Conclusion Com-pared with two-dimensional ultrasound, four-dimensional color Doppler ultrasound in the detection of fetal abnormalities has obvious advantages, which is worth clinical application.

  10. Echocardiography practice, training and accreditation in the intensive care: document for the World Interactive Network Focused on Critical Ultrasound (WINFOCUS

    Directory of Open Access Journals (Sweden)

    Catena Emanuele

    2008-10-01

    Full Text Available Abstract Echocardiography is increasingly used in the management of the critically ill patient as a non-invasive diagnostic and monitoring tool. Whilst in few countries specialized national training schemes for intensive care unit (ICU echocardiography have been developed, specific guidelines for ICU physicians wishing to incorporate echocardiography into their clinical practice are lacking. Further, existing echocardiography accreditation does not reflect the requirements of the ICU practitioner. The WINFOCUS (World Interactive Network Focused On Critical UltraSound ECHO-ICU Group drew up a document aimed at providing guidance to individual physicians, trainers and the relevant societies of the requirements for the development of skills in echocardiography in the ICU setting. The document is based on recommendations published by the Royal College of Radiologists, British Society of Echocardiography, European Association of Echocardiography and American Society of Echocardiography, together with international input from established practitioners of ICU echocardiography. The recommendations contained in this document are concerned with theoretical basis of ultrasonography, the practical aspects of building an ICU-based echocardiography service as well as the key components of standard adult TTE and TEE studies to be performed on the ICU. Specific issues regarding echocardiography in different ICU clinical scenarios are then described. Obtaining competence in ICU echocardiography may be achieved in different ways – either through completion of an appropriate fellowship/training scheme, or, where not available, via a staged approach designed to train the practitioner to a level at which they can achieve accreditation. Here, peri-resuscitation focused echocardiography represents the entry level – obtainable through established courses followed by mentored practice. Next, a competence-based modular training programme is proposed: theoretical

  11. Role of Echocardiography in the Diagnostic Assessment and Etiology of Heart Failure in Older Adults: Opacify, Quantify, and Rectify.

    Science.gov (United States)

    Gupta, Vedant A; Nanda, Navin C; Sorrell, Vincent L

    2017-07-01

    Echocardiography allows the assessment of systolic and diastolic function and identifies many of the common causes of heart failure (HF). Patients with minimally symptomatic or unsuspected left ventricular systolic dysfunction may be identified and receive the benefits of angiotensin-converting enzyme inhibitor therapy. Echocardiography is also for assessing prognosis and can be used serially to evaluate treatment. Ventricular filling pressures, pulmonary artery pressures, and cardiac output can be sequentially determined. The authors believe that all patients with HF should receive careful assessment echocardiography. The authors believe using echocardiography is especially valuable in the elderly. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Four-dimensional computed tomography based assessment and analysis of lung tumor motion during free-breathing respiration%基于四维CT影像肺内肿瘤运动度的测量与分析

    Institute of Scientific and Technical Information of China (English)

    王彦; 包勇; 张黎; 樊卫; 邓小武; 陈明

    2010-01-01

    目的 以四维CT(4DCT)影像量化肺内肿瘤因呼吸导致的运动,分析其影响因素,寻找运动度大的肿瘤特征.方法 在平静呼吸状态下接受4DCT扫描的肺内肿瘤患者43例,肺内可测量病灶44个.由同一位医生在4DCT各时相数据集卜勾画肿瘤GTV,分别测量GTV中心点在上下、左右、前后三维方向上的运动幅度.对与运动度可能相关的临床变量和解剖学因素进行统计学分析.以任意方向运动幅度>5 mm作为分界点,分析此类肿瘤特征.结果 肺内肿瘤运动度与T分期、GTV体积、肺内所处上下位置、与固定组织(如胸壁、纵隔、脊柱)粘连程度相关.10例患者肺内肿瘤的运动幅度>5 mm,均位于胸腔下部及后部,上下方向运动度最大,最大值为14.4 mm.95%肺内肿瘤的运动幅度在上下方向<11.8 mm,前后方向<4.6 mm,左右方向<2.7 mm.结论 呼吸导致的肺内肿瘤运动度受肿瘤位置、体积、T分期及粘连程度等因素影响.下叶肺内孤立肿瘤的运动度最大,主要发生在上下方向,上叶后段肿瘤的运动度次之.%Objective To quantify the amplitudes of lung tumor motion during free-breathing using four dimensional computed tomography (4DCT), and seek the characteristics of tumors with large motion. Methods Respiratory-induced tumor motion was analyzed for 44 tumors from 43 patients. All patients un-derwent 4DCT during free-breathing before treatment. Gross tumor volumes (GTV) on ten respiratory phases were contoured by the same doctor. The eentroids of GTVs were autoplaeed with treatment software (ADAC Pinnacle 7.4f), then the amplitudes of tumor motion were assessed. The various clinical and anatomic fac-tors associated with GTV motion were analyzed. The characteristics of tumors with motion greater than 5 mm in any direction were explored. Results The tumor motion was found to be associated with T stage, GTV size, the superior-inferior (SI) tumor location in the lung, and the attachment

  13. Left Atrial Dysfunction in the Pathogenesis of Cryptogenic Stroke: Novel Insights from Speckle-Tracking Echocardiography.

    Science.gov (United States)

    Leong, Darryl P; Joyce, Emer; Debonnaire, Philippe; Katsanos, Spyridon; Holman, Eduard R; Schalij, Martin J; Bax, Jeroen J; Delgado, Victoria; Marsan, Nina Ajmone

    2017-01-01

    Myocardial strain analysis by speckle-tracking echocardiography, which can detect subtle abnormalities in left atrial (LA) function, may offer unique insights into LA pathophysiology in patients with cryptogenic stroke (CS). The aim of this study was to investigate whether LA reservoir strain by speckle-tracking echocardiography, as a measure of LA compliance, is impaired in patients with CS and no history of atrial fibrillation. A retrospective case-control study of 742 patients (mean age, 59 ± 13 years; 54% men; 371 with CS and 371 control subjects) was conducted. LA reservoir strain was quantified using speckle-tracking echocardiography. LA strain was significantly lower among patients with CS than control subjects (30 ± 7.3% vs 34 ± 6.7%, P speckle-tracking echocardiography, is associated with CS independent of other cardiovascular risk factors. These findings suggest a potential role for LA strain to risk-stratify patients in the prevention of stroke. Copyright © 2016 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

  14. Detection of heart disease by open access echocardiography: a retrospective analysis of general practice referrals.

    Science.gov (United States)

    Chambers, John; Kabir, Saleha; Cajeat, Eric

    2014-02-01

    Heart disease is difficult to detect clinically and it has been suggested that echocardiography should be available to all patients with possible cardiac symptoms or signs. To analyse the results of 2 years of open access echocardiography for the frequency of structural heart disease according to request. Retrospective database analysis in a teaching hospital open access echocardiography service. Reports of all open access transthoracic echocardiograms between January 2011 and December 2012 were categorised as normal, having minor abnormalities, or significant abnormalities according to the indication. There were 2343 open access echocardiograms performed and there were significant abnormalities in 29%, predominantly valve disease (n = 304, 13%), LV systolic dysfunction (n = 179, 8%), aortic dilatation (n = 80, 3%), or pulmonary hypertension (n = 91, 4%). If echocardiography had been targeted at a high-risk group, 267 with valve disease would have been detected (compared to 127 with murmur alone) and 139 with LV systolic dysfunction (compared to 91 with suspected heart failure alone). Most GP practices requested fewer than 10 studies, but 6 practices requested over 70 studies. Open access echocardiograms are often abnormal but structural disease may not be suspected from the clinical request. Uptake by individual practices is patchy. A targeted expansion of echocardiography in patients with a high likelihood of disease is therefore likely to increase the detection of clinically important pathology.

  15. Evaluation of Myocardial Viability after Myocardial Infarction with Intravenous Real-time Myocardial Contrast Echocardiography

    Institute of Scientific and Technical Information of China (English)

    Weihui SHENTU; Yuhan WU; Youbin DENG; Runqing HUANG; Peng LI; Xiang WEI; Haoyi YANG; Yun ZHANG; Li XIONG; Fen YU

    2008-01-01

    The myocardial viability after myocardial infarction was evaluated by intravenous myocardial contrast echocardiography. Intravenous real-time myocardial contrast echocardiography was performed on 18 patients with myocardial infarction before coronary revascularization. Follow-up echocardiography was performed 3 months after coronary revascularization. Segmental wall motion was assessed using 18-segment LV model and classified as normal, hypokinesis, akinesis and dyskinesis. Viable myocardium was defined by evident improvement of segmental wall motion 3 months after coronary revascularization. Myocardial perfusion was assessed by visual interpretation and divided into 3 conditions: homogeneous opacification; partial or reduced opaciflcation or subendocardial contrast defect; contrast defect. The former two conditions were used as the standard to define the viable myocardium. The results showed that 109 abnormal wall motion segments were detected among 18 patients with myocardial infarction, including 47 segments of hypokinesis, 56 segments of akinesis and 6 segments of dyskinesis. The wall motion of 2 segments with hypokinesis before coronary revascularization which showed homogeneous opacification, 14 of 24 segments with hypokinese and 20 of 24 segments with akinese before coronary revascularization which showed partial or reduced opaciflcation or subendocardial contrast defect was improved 3 months after coronary revascularization. In our study, the sensitivity and specificity of evaluation of myocardial viability after myocardial infarction by intravenous real-time myocardial contrast echocardiography were 94.7% and 78.9%, respectively. It was concluded that intravenous real-time myocardial contrast echocardiography could accurately evaluate myocardial viability after myocardial infarction.

  16. Multidetector CT evaluation of total anomalous pulmonary venous connections: comparison with echocardiography

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Ki Ho; Choo, Ki Seok [Pusan National University Hospital, Department of Radiology, Medical Institute, Pusan (Korea); Lim, Soo Jin [Kim Hae Joong Ang Hospital, Department of Cardiology, Kimhae (Korea); Lee, Hyoung Doo; Park, Ji Ae; Jo, Min Jung [Pusan National University Hospital, Department of Paediatrics, Pusan (Korea); Sung, Si Chan; Chang, Yun Hee [Pusan National University Hospital, Department of Thoracic and Cardiovascular Surgery, Pusan (Korea); Jeong, Dong Wook [Pusan National University Hospital, Department of Family Medicine, Pusan (Korea); Kim, Siho [Dong-A University Hospital, Department of Thoracic and Cardiovascular Surgery, Pusan (Korea)

    2009-09-15

    Although echocardiography is the first-line imaging modality in the diagnosis of total anomalous pulmonary venous connection (TAPVC), multidetector CT (MDCT) could have advantages in the diagnosis of TAPVC in certain cases. To compare MDCT with echocardiography in the evaluation of TAPVC. Enrolled in the study were 23 patients with surgically proven TAPVC. The echocardiography and MDCT findings were independently interpreted by a paediatric cardiologist and cardiac radiologist in terms of: (1) the drainage site of the common pulmonary vein, (2) stenosis of the vertical vein, and (3) the course of the atypical vessel into the systemic vein in the case of vertical vein stenosis. The findings from both modalities were correlated with the results obtained at surgery (n=22) or autopsy (n=1). In all patients, MDCT correctly depicted the drainage site of the common pulmonary vein, stenosis of the vertical vein and the course of the atypical vessel into the systemic vein (sensitivity 100%, specificity 100%). The specificity of echocardiography was 100% for the three defined findings. The sensitivity of echocardiography, however, was 87%, 71% and 0%, respectively. MDCT can facilitate the diagnosis of TAPVC in certain cases. (orig.)

  17. Simplified single plane echocardiography is comparable to conventional biplane two-dimensional echocardiography in the evaluation of left atrial volume: a study validated by three-dimensional echocardiography in 143 individuals.

    Science.gov (United States)

    Vieira-Filho, Normando G; Mancuso, Frederico J N; Oliveira, Wercules A A; Gil, Manuel A; Fischer, Cláudio H; Moises, Valdir A; Campos, Orlando

    2014-03-01

    The left atrial volume index (LAVI) is a biomarker of diastolic dysfunction and a predictor of cardiovascular events. Three-dimensional echocardiography (3DE) is highly accurate for LAVI measurements but is not widely available. Furthermore, biplane two-dimensional echocardiography (B2DE) may occasionally not be feasible due to a suboptimal two-chamber apical view. Simplified single plane two-dimensional echocardiography (S2DE) could overcome these limitations. We aimed to compare the reliability of S2DE with other validated echocardiographic methods in the measurement of the LAVI. We examined 143 individuals (54 ± 13 years old; 112 with heart disease and 31 healthy volunteers; all with sinus rhythm, with a wide range of LAVI). The results for all the individuals were compared with B2DE-derived LAVIs and validated using 3DE. The LAVIs, as determined using S2DE (32.7 ± 13.1 mL/m(2)), B2DE (31.9 ± 12.7 mL/m(2)), and 3DE (33.1 ± 13.4 mL/m(2)), were not significantly different from each other (P = 0.85). The S2DE-derived LAVIs correlated significantly with those obtained using both B2DE (r = 0.98; P < 0.001) and 3DE (r = 0.93; P < 0.001). The mean difference between the S2DE and B2DE measurements was <1.0 mL/m(2). Using the American Society of Echocardiography criteria for grading LAVI enlargement (normal, mild, moderate, severe), we observed an excellent agreement between the S2DE- and B2DE-derived classifications (κ = 0.89; P < 0.001). S2DE is a simple, rapid, and reliable method for LAVI measurement that may expand the use of this important biomarker in routine echocardiographic practice.

  18. Fetal cardiac ventricular volume, cardiac output, and ejection fraction determined with four-dimensional ultrasound using Spatio-Temporal Image Correlation (STIC) and Virtual Organ Computed-aided AnaLysis (VOCAL™)

    Science.gov (United States)

    Hamill, Neil; Yeo, Lami; Romero, Roberto; Hassan, Sonia S.; Myers, Stephen A.; Mittal, Pooja; Kusanovic, Juan Pedro; Balasubramaniam, Mamtha; Chaiworapongsa, Tinnakorn; Vaisbuch, Edi; Espinoza, Jimmy; Gotsch, Francesca; Goncalves, Luis F.; Lee, Wesley

    2011-01-01

    Objective To quantify fetal cardiovascular parameters with Spatio-Temporal Image Correlation (STIC) and Virtual Organ Computed-aided AnaLysis (VOCAL™) utilizing the sub-feature: “Contour Finder: Trace”. Study Design A cross-sectional study was designed consisting of patients with normal pregnancies between 19 and 40 weeks of gestation. After STIC datasets were acquired, analysis was performed offline (4DView) and the following cardiovascular parameters were evaluated: ventricular volume in end systole and end diastole, stroke volume, cardiac output, and ejection fraction. To account for fetal size, cardiac output was also expressed as a function of head circumference, abdominal circumference, or femoral diaphysis length. Regression models were fitted for each cardiovascular parameter to assess the effect of gestational age and paired comparisons were made between the left and right ventricles. Results 1) Two hundred and seventeen patients were retrospectively identified, of whom 184 had adequate STIC datasets (85% acceptance); 2) ventricular volume, stroke volume, cardiac output, and adjusted cardiac output increased with gestational age; whereas, the ejection fraction decreased as gestation advanced; 3) the right ventricle was larger than the left in both systole (Right: 0.50 ml, IQR: 0.2 – 0.9; vs. Left: 0.27 ml, IQR: 0.1 – 0.5; p<0.001) and diastole (Right: 1.20 ml, IQR: 0.7 – 2.2; vs. Left: 1.03 ml, IQR: 0.5 – 1.7; p<0.001); 4) there were no differences between the left and right ventricle with respect to stroke volume, cardiac output, or adjusted cardiac output; and 5) the left ventricular ejection fraction was greater than the right (Left: 72.2%, IQR: 64 – 78; vs. Right: 62.4%, IQR: 56 – 69; p<0.001). Conclusion Fetal echocardiography, utilizing STIC and VOCAL™ with the sub-feature: “Contour Finder: Trace”, allows assessment of fetal cardiovascular parameters. Normal fetal cardiovascular physiology is characterized by ventricular

  19. Assessment of Left Ventricular Myocardial Viability by 3-Dimensional Speckle-Tracking Echocardiography in Patients With Myocardial Infarction.

    Science.gov (United States)

    Ran, Hong; Zhang, Ping-Yang; Zhang, You-Xiang; Zhang, Jian-Xin; Wu, Wen-Fang; Dong, Jing; Ma, Xiao-Wu

    2016-08-01

    To determine whether 3-dimensional (3D) speckle-tracking echocardiography could provide a new way to assess myocardial viability in patients with myocardial infarction (MI). Forty-five patients with MI underwent routine echocardiography, 2-dimensional (2D) speckle-tracking echocardiography, and 3D speckle-tracking echocardiography. Radionuclide myocardial perfusion/metabolic imaging was used as a reference standard to define viable and nonviable myocardia. Among 720 myocardial segments in 45 patients, 368 showed abnormal motion on routine echocardiography; 204 of 368 were categorized as viable on single-photon emission computed tomography/positron emission tomography (SPECT/PET), whereas 164 were defined as nonviable; 300 normal segments on SPECT/PET among 352 segments without abnormal motion on routine echocardiography were categorized as a control group. The radial, longitudinal, 3D, and area strain on 3D speckle-tracking echocardiography had significant differences between control and nonviable groups (P speckle-tracking echocardiography between viable and nonviable groups. Although there was no significant difference in circumferential strain between the groups, radial and longitudinal strain from 3D speckle-tracking echocardiography decreased significantly in the nonviable group. Moreover, 3D and area strain values were lower in the nonviable segments than the viable segments. By receiver operating characteristic analysis, radial strain from 3D speckle-tracking echocardiography with a cutoff of 11.1% had sensitivity of 95.1% and specificity of 53.4% for viable segments; longitudinal strain with a cutoff of 14.3% had sensitivity of 65.2% and specificity of 65.7%; 3D strain with a cutoff of 17.4% had sensitivity of 70.6% and specificity of 77.2%; and area strain with a cutoff of 23.2% had sensitivity of 91.5% and specificity of 82.8%. Three-dimensional speckle-tracking echocardiography might have potential for detection of myocardial viability in patients with

  20. Transthoracic Doppler echocardiography – noninvasive diagnostic window for coronary flow reserve assessment

    Directory of Open Access Journals (Sweden)

    Dimitrow Paweł

    2003-04-01

    Full Text Available Abstract This review focuses on transthoracic Doppler echocardiography as noninvasive method used to assess coronary flow reserve (CFR in a wide spectrum of clinical settings. Transthoracic Doppler echocardiography is rapidly gaining appreciation as popular tool to measure CFR both in stenosed and normal epicardial coronary arteries (predominantly in left anterior descending coronary artery. Post-stenotic CFR measurement is helpful in: functional assessment of moderate stenosis, detection of significant or critical stenosis, monitoring of restenosis after revascularization. In the absence of stenosis in the epicardial coronary artery, decreased CFR enable to detect impaired microvascular vasodilatation in: reperfused myocardial infarct, arterial hypertension with or without left ventricular hypertrophy, diabetes mellitus, hypercholesterolemia, syndrome X, hypertrophic cardiomyopathy. In these diseases, noninvasive transthoracic Doppler echocardiography allows for serial CFR evaluations to explore the effect of various pharmacological therapies.

  1. CLINICAL ASSESSMENT OF BIPLANAR TRANSESOPHAGEAL ECHOCARDIOGRAPHY- A REPORT OF 125 CASES

    Institute of Scientific and Technical Information of China (English)

    王国干; 孟宪强; 樊朝美; 张辉; 刘醒; 刘汉英; 蔡如升

    1994-01-01

    One hundred and twenty-five patients with cardiovascular disease were examined by biplanar transesophageal echocardiography(BTEE),including 67 with rheumatic heart disease(7 monitored during operation),22 with aortic diseases,20 with congenital heart diseases,and 16 with other kinds of heart disease.The results showed that BTEE was not influenced by corpulent and pulmonary emphysema and was better than transthoracic echocardiography at imaging the interatrial septum.left atrium and left atrial appendage,thoracic aorta,and mitral artificial valve and at intraoperative monitoring.BTEE was also better than single-plane transesophageal echocardiography,because BTEE could be used to observe the heart and thoracic aorta in transverse and longitudinal planes,thus englarging the transmission"window" as well as allowing the entire lesin to be imaged.

  2. Predicting Cardiotoxic Effects of Carbon Monoxide Poisoning Using Speckle Tracking Echocardiography.

    Science.gov (United States)

    Saraçoğlu, Erhan; Vuruşkan, Ertan; Kılıç, Salih; Çekici, Yusuf; Onur, Bahaeddin; Arslan, Yavuz; Kılıç, Ertuğrul; Aykut, Ömer

    2017-10-06

    Carbon monoxide (CO) poisoning could cause significant cardiac injury. This study aimed to evaluate patients with CO poisoning by using speckle tracking echocardiography (STE), a potentially more sensitive technique, to identify left systolic ventricular dysfunction for the first time in the literature. Seventy-two patients who were exposed to CO poisoning were studied. Blood collection and echocardiography were performed at admission and after patients' discharge on days 10-15 (mean 12 days). Global longitudinal strain (GLS) and global circumferential strain (GCS) were calculated using STE. In order to find the normal strain levels and to compare it to the patient with CO poisoning, 35 healthy subjects were included in the study. Left ventricular ejection fraction was analyzed according to Simpson's method. Patients were divided into two groups based on their LVEF values. LVEF Speckle tracking echocardiography has the potential of demonstrating subtle LV systolic dysfunction even in CO poisoning patients with preserved EF.

  3. Echocardiography-based left ventricular mass estimation. How should we define hypertrophy?

    Science.gov (United States)

    Foppa, Murilo; Duncan, Bruce B; Rohde, Luis E P

    2005-06-17

    Left ventricular hypertrophy is an important risk factor in cardiovascular disease and echocardiography has been widely used for diagnosis. Although an adequate methodologic standardization exists currently, differences in measurement and interpreting data is present in most of the older clinical studies. Variability in border limits criteria, left ventricular mass formulas, body size indexing and other adjustments affects the comparability among these studies and may influence both the clinical and epidemiologic use of echocardiography in the investigation of the left ventricular structure. We are going to review the most common measures that have been employed in left ventricular hypertrophy evaluation in the light of some recent population based echocardiographic studies, intending to show that echocardiography will remain a relatively inexpensive and accurate tool diagnostic tool.

  4. Echocardiography-based left ventricular mass estimation. How should we define hypertrophy?

    Directory of Open Access Journals (Sweden)

    Rohde Luis EP

    2005-06-01

    Full Text Available Abstract Left ventricular hypertrophy is an important risk factor in cardiovascular disease and echocardiography has been widely used for diagnosis. Although an adequate methodologic standardization exists currently, differences in measurement and interpreting data is present in most of the older clinical studies. Variability in border limits criteria, left ventricular mass formulas, body size indexing and other adjustments affects the comparability among these studies and may influence both the clinical and epidemiologic use of echocardiography in the investigation of the left ventricular structure. We are going to review the most common measures that have been employed in left ventricular hypertrophy evaluation in the light of some recent population based echocardiographic studies, intending to show that echocardiography will remain a relatively inexpensive and accurate tool diagnostic tool.

  5. Identification of viable myocardium early after acute myocardial infarction under beta-blockade by enoximone echocardiography.

    Science.gov (United States)

    Natale, E; Minardi, G; Wang, F; Tubaro, M; Giovannini, E; Vajola, S F; Milazzotto, F

    1997-04-01

    The influence of the beta-blocker metoprolol on the capacity either of low-dose dobutamine echocardiography or the recently introduced enoximone echocardiography to detect viable dysfunctioning myocardium after myocardial infarction was investigated. Initial clinical experience would suggest that the phosphodiesterase III inhibitor enoximona could be an alternative pharmacological stimulation, inducing an increase in contractility in the presence or absence of beta-receptor stimulation. Ten patients with a baseline low-dose dobutamine-echocardiographic test (up to 10 micrograms/kg/min) positive for myocardial viability in > or = 1 segment(s), performed 4-5 days after a first acute myocardial infarction treated with rtPA, were randomized after the administration of intravenous metoprolol (15 mg in three 5-mg boluses) either to dobutamine (up to 15 micrograms/kg/min) or to an enoximone intravenous bolus (1 mg/kg over 5 min) under echocardiographic monitoring, in a crossover sequence, with a 24-h interval. The infarct related artery was patent (TIMI grade 2 o 3) in all the patients. Follow-up echocardiograms were performed 5-7 weeks later. Resting asynergy was found in 40 segments; of these, 17 were viable. All the viable segments remained unresponsive during the post-metoprolol dobutamine infusion, while improved their contractility during enoximone echocardiography. Two patients suffering from early post-infarction angina underwent coronary angioplasty successfully. Eight out of ten patients (2 revascularized and 6 not) showed contractile recovery in a total of 14 segments at the follow-up echocardiogram. Sensitivity, specificity and overall accuracy in predicting reversible dysfunction after acute myocardial infarction for enoximone echocardiography were 93, 85, and 88%, respectively. Our results support the value of enoximone echocardiography in the identification of myocardial viability after myocardial infarction, in patients treated with beta-blockers, which

  6. Echocardiography integrated ACLS protocol versus con-ventional cardiopulmonary resuscitation in patients with

    Directory of Open Access Journals (Sweden)

    Chardoli Mojtaba

    2012-11-01

    Full Text Available 【Abstract】Objective: To examine the utility of bedside echocardiography in detecting the reversible causes of pulseless electrical activity (PEA cardiac arrest and pre-dicting the resuscitation outcomes. Methods: In this prospective interventional study, pa-tients presenting with PEA cardiac arrest were randomized into two groups. In Group A, ultrasound trained emergency physicians performed echocardiography evaluating cardiac activity, right ventricle dilation, left ventricle function, peri-cardial effusion/tamponade and IVC size along with the ad-vanced cardiac life support (ACLS protocol. Patients in Group B solely underwent ACLS protocol without applying echocardiography. The presence or absence of mechanical ventricular activity (MVA and evidences of PEA reversible causes were recorded. The return of spontaneous circulation (ROSC and death were evaluated in both groups. Results: One hundred patients with the mean age of (58±6.1 years were enrolled in this study. Fifty patients (Group A had echocardiography detected in parallel with cardiopulmonary resuscitation (CPR. Among them, 7 pa-tients (14% had pericardial effusion, 11 (22% had hypovolemia, and 39 (78% were revealed the presence of MVA. In the pseudo PEA subgroup (presence of MVA, 43% had ROSC (positive predictive value and in the true PEA subgroup with cardiac standstill (absence of MVA, there was no recorded ROSC (negative predictive value. Among patients in Group B, no reversible etiology was detected. There was no significant difference in resuscitation results between Groups A and B observed (P=0.52. Conclusion: Bedside echocardiography can identify some reversible causes of PEA. However, there are no sig-nificant changes in survival outcome between the echo group and those with traditional CPR. Key words: Heart arrest; Echocardiography; Car-diopulmonary resuscitation

  7. Three-dimensional Echocardiography of Right Ventricular Function Correlates with Severity of Pediatric Pulmonary Hypertension.

    Science.gov (United States)

    Jone, Pei-Ni; Patel, Sonali S; Cassidy, Courtney; Ivy, David Dunbar

    2016-12-01

    Right ventricular function and biomarkers of B-type natriuretic peptide (BNP) and N-Terminal pro-BNP (NT pro-BNP) are used to determine the severity of right ventricular failure and outcomes from pulmonary hypertension. Real-time three-dimensional echocardiography (3DE) is a novel quantitative measure of the right ventricle and decreases the geometric assumptions from conventional two-dimensional echocardiography (2DE). We correlated right ventricular functional measures using 2DE and single-beat 3DE with biomarkers and hemodynamics to determine the severity of pediatric pulmonary hypertension. We retrospectively evaluated 35 patients (mean age 12.67 ± 5.78 years) with established pulmonary hypertension who had echocardiograms and biomarkers on the same day. Ten out of 35 patients had hemodynamic evaluation within 3 days. 2DE evaluation included tricuspid annular plane systolic excursion (TAPSE), right ventricular myocardial performance index from tissue Doppler imaging (RV TDI MPI), and right ventricular fractional area change (FAC). Three-dimensional echocardiography evaluation included right ventricular ejection fraction (EF), end-systolic volume, and end-diastolic volume. The quality of the 3DE was graded as good, fair, or poor. Pearson correlation coefficients were utilized to evaluate between biomarkers and echocardiographic parameters and between hemodynamics and echocardiography. Three-dimensional echocardiography and FAC correlated significantly with BNP and NT pro-BNP. TAPSE and RV TDI MPI did not correlate significantly with biomarkers. 3D right ventricular EF correlated significantly with hemodynamics. Two-dimensional echocardiography did not correlate with hemodynamics. Single-beat 3DE is a noninvasive, feasible tool in the quantification of right ventricular function and maybe more accurate than conventional 2DE in evaluating severity of pulmonary hypertension. © 2016 Wiley Periodicals, Inc.

  8. Abnormal echocardiography in patients with type 2 diabetes and relation to symptoms and clinical characteristics

    DEFF Research Database (Denmark)

    Jørgensen, Peter Godsk; Jensen, Magnus Thorsten; Mogelvang, Rasmus

    2016-01-01

    OBJECTIVES: We aimed to determine the prevalence of echocardiographic abnormalities and their relation to clinical characteristics and cardiac symptoms in a large, contemporary cohort of patients with type 2 diabetes. RESULTS: A total of 1030 patients with type 2 diabetes participated....... Echocardiographic abnormalities were present in 513 (49.8%) patients, mainly driven by a high prevalence of diastolic dysfunction 178 (19.4%), left ventricular hypertrophy 213 (21.0%) and left atrial enlargement, 200 (19.6%). The prevalence increased markedly with age from 31.1% in the youngest group (... with abnormal echocardiography along with dyspnoea and characteristic chest pain (p patients with abnormal echocardiography. CONCLUSION: Echocardiographic abnormalities...

  9. Clinical application of echocardiography in detection of foetal arrhythmia:a retrospective study of 451 foetuses

    Institute of Scientific and Technical Information of China (English)

    赵博文; 张松英; 潘美; 徐海珊; 寿金朵; 吕江红; 汤富刚; 范妙英; 范晓明; 林莎

    2004-01-01

    @@Foetal arrhythmia is defined as any irregular foetal cardiac rhythm or regular rhythm at a rate outside the reference range of 120 to 160 beats/minute. Foetal echocardiography permits accurate determination of the structural characteristics and the nature of the arrhythmia in foetuses. It is particularly indicated for mothers from high-risk groups. Management of diagnosed heart disease, including foetal arrhythmia, leads either to the termination of pregnancy or to optimal postnatal care of baby and mother. This retrospective study examined the application of foetal echocardiography in the diagnosis of foetal arrhythmia and its clinical significance.

  10. The Heart of the Matter: Increasing Quality and Charge Capture from Intraoperative Transesophageal Echocardiography.

    Science.gov (United States)

    Sanford, Joseph A; Kadry, Bassam; Oakes, Daryl; Macario, Alex; Schmiesing, Cliff

    2016-04-15

    Although transesophageal echocardiography is routinely performed at our institution, there is no easy way to document the procedure in the electronic medical record and generate a bill compliant with reimbursement requirements. We present the results of a quality improvement project that used agile development methodology to incorporate intraoperative transesophageal echocardiography into the electronic medical record. We discuss improvements in the quality of clinical documentation, technical workflow challenges overcome, and cost and time to return on investment. Billing was increased from an average of 36% to 84.6% when compared with the same time period in the previous year. The expected recoupment of investment for this project is just 18 weeks.

  11. Dobutamine Stress Echocardiography Safety in Chagas Disease Patients.

    Science.gov (United States)

    Rassi, Daniela do Carmo; Vieira, Marcelo Luiz Campos; Furtado, Rogerio Gomes; Turco, Fabio de Paula; Melato, Luciano Henrique; Hotta, Viviane Tiemi; Nunes, Colandy Godoy de Oliveira; Rassi, Luiz; Rassi, Salvador

    2017-02-01

    A few decades ago, patients with Chagas disease were predominantly rural workers, with a low risk profile for obstructive coronary artery disease (CAD). As urbanization has increased, they became exposed to the same risk factors for CAD of uninfected individuals. Dobutamine stress echocardiography (DSE) has proven to be an important tool in CAD diagnosis. Despite being a potentially arrhythmogenic method, it is safe for coronary patients without Chagas disease. For Chagas disease patients, however, the indication of DSE in clinical practice is uncertain, because of the arrhythmogenic potential of that heart disease. To assess DSE safety in Chagas disease patients with clinical suspicion of CAD, as well as the incidence of arrhythmias and adverse events during the exam. Retrospective analysis of a database of patients referred for DSE from May/2012 to February/2015. This study assessed 205 consecutive patients with Chagas disease suspected of having CAD. All of them had their serology for Chagas disease confirmed. Their mean age was 64±10 years and most patients were females (65.4%). No patient had significant adverse events, such as acute myocardial infarction, ventricular fibrillation, asystole, stroke, cardiac rupture and death. Regarding arrhythmias, ventricular extrasystoles occurred in 48% of patients, and non-sustained ventricular tachycardia in 7.3%. DSE proved to be safe in this population of Chagas disease patients, in which no potentially life-threatening outcome was found. Até poucas décadas atrás, os pacientes chagásicos eram predominantemente trabalhadores rurais, com baixo perfil de risco para doença obstrutiva coronária. Com a crescente urbanização, passaram a ter os mesmos fatores de risco para doença aterosclerótica que indivíduos não infectados. O ecocardiograma sob estresse com dobutamina (EED) é uma importante ferramenta no diagnóstico de coronariopatia. É referido, porém, como um método potencialmente arritmogênico, mas

  12. Effect of catheter-based renal denervation on left ventricular function, mass and (un)twist with two-dimensional speckle tracking echocardiography

    NARCIS (Netherlands)

    L. Feyz (Lida); B.M. van Dalen (Bas); M.L. Geleijnse (Marcel); N.M. van Mieghem (Nicolas); R.T. van Domburg (Ron); J. Daemen (Joost)

    2017-01-01

    markdownabstractBackground: Speckle tracking echocardiography (STE) is an echocardiography modality that is able to measure left ventricular (LV) characteristics, including rotation, strain and strain rate. Strain measures myocardial fibre contraction and relaxation. This study aims to assess the

  13. Computed tomography and echocardiography in patients with acute pulmonary embolism: part 1: correlation of findings of right ventricular enlargement.

    Science.gov (United States)

    Wake, Nicole; Kumamaru, Kanako K; George, Elizabeth; Bedayat, Arash; Ghosh, Nina; Gonzalez Quesada, Carlos; Rybicki, Frank J; Gerhard-Herman, Marie

    2014-01-01

    To evaluate the correlation between the computed tomography (CT)-derived right ventricle (RV) to left ventricle (LV) diameter ratio and the RV size determined by echocardiography in patients with acute pulmonary embolism. Consecutive CT pulmonary angiography examinations (August 2003 to May 2010) from a single, large, urban teaching hospital were retrospectively reviewed. For a cohort of 777 subjects who underwent echocardiography within 48 hours of the CT acquisition, the qualitative RV size (divided into 5 categories) extracted from the echocardiography report was correlated with the CT-derived RV/LV diameter ratio. There was moderate correlation (Spearman rank correlation coefficient=0.54, Psize as determined by echocardiography. The correlation coefficient and the concordance rate were inversely related to the time difference between the acquisitions of the 2 modalities. CT and echocardiography findings to assess the RV size after acute pulmonary embolism have moderate correlation.

  14. Manual Skill Acquisition During Transesophageal Echocardiography Simulator Training of Cardiology Fellows : A Kinematic Assessment

    NARCIS (Netherlands)

    Matyal, Robina; Montealegre-Gallegos, Mario; Mitchell, John D.; Kim, Han; Bergman, Remco; Hawthorne, Katie M.; O'Halloran, David; Wong, Vanessa; Hess, Phillip E.; Mahmood, Feroze

    2015-01-01

    Objective: To investigate whether a transesophageal echocardiography (TEE) simulator with motion analysis can be used to impart proficiency in TEE in an integrated curriculum-based model. Design: A prospective cohort study. Setting: A tertiary-care university hospital. Participants: TEE-naive cardio

  15. Right Atrial Appendage Aneurysm in a Newborn Diagnosed with Fetal Echocardiography

    Science.gov (United States)

    Yartaşı Tik, Elif; Öztarhan, Kazım; Dedeoğlu, Reyhan; Çetinkaya, Merih

    2016-01-01

    Right atrial appendage aneurysm is a very rare condition which can be asymptomatic or can cause arrhythmia or life-threatening thromboembolism. We report a case of newborn with right atrial appendage aneurysm who was diagnosed with fetal echocardiography. Anticoagulant therapy was applied to prevent thromboembolism and he is still going on follow-up without any complaint. PMID:27703828

  16. Left atrial ball thrombus with acute mesenteric ischemia: Anesthetic management and role of transesophageal echocardiography

    Directory of Open Access Journals (Sweden)

    Neeti Makhija

    2014-01-01

    Full Text Available A 62 year old female with severe mitral stenosis, large left atrial ball thrombus and acute mesenteric ischemia emergently underwent mitral valve replacement, left atrial clot removal and emergency laparotomy for mesenteric ischemia. Peri-operative management issues, particularly, the anesthetic challenges and the role of transesophageal echocardiography are discussed.

  17. The influence of transoesophageal echocardiography on intra-operative decision making - A European multicentre study

    NARCIS (Netherlands)

    Kolev, N; Brase, R; Swanevelder, J; Oppizzi, M; Riesgo, MJ; van der Maaten, JMAA; Abiad, MG; Guarracino, F; Zimpfer, M

    1998-01-01

    The role of transoesophageal echocardiography (TOE) in anaesthesia remains controversial because it is a rapidly evolving technique with few proven benefits and considerable cost. Recently, the Society of Cardiovascular Anaesthesiologists has published practice guidelines for the use of peri-operati

  18. Off-pump atrial septostomy with thoracoscopic scissors under transesophageal echocardiography guidance

    Directory of Open Access Journals (Sweden)

    Raj R Benedict

    2013-01-01

    Full Text Available Selected children with congenital heart defects undergoing palliative closed heart procedures require a cardiopulmonary bypass (CPB run only for the purpose of creating an inter-atrial communication. We report a simple technique of atrial septostomy using thoracoscopy scissors under transesophageal echocardiography guidance without the need for CPB.

  19. The Role of Stress Echocardiography in Valvular Heart Disease: A Current Appraisal.

    Science.gov (United States)

    Gentry Iii, James L; Phelan, Dermot; Desai, Milind Y; Griffin, Brian P

    2017-04-11

    Stress echocardiography is a widely available, safe, low-cost, versatile imaging modality which is becoming increasingly recognized as a valuable tool in the assessment of patients with native and prosthetic left-sided valvular heart disease. It provides a quantitative assessment to help guide clinical decision-making when discordance exists between symptoms and severity of valve disease. Exercise (treadmill or bicycle) remains the preferred stress modality, but pharmacological augmentation with dobutamine can be used if needed. Low-dose dobutamine stress echocardiography is specifically valuable in patients with low-flow, low-gradient aortic stenosis when attempting to differentiate true severe aortic stenosis from pseudo-severe aortic stenosis. Stress echocardiography not only identifies high-risk features that indicate need for earlier surgery, it also provides useful information for the peri- and postoperative period, including long-term outcome, risk stratification to guide monitoring frequency, and offers guidance for eligibility in competitive sports participation. As research continues to expand the utility of stress echocardiography in the management of patients with valvular heart disease, future research should focus on the recognition of newer parameters identifying high-risk features including subsequent validation in a large population.

  20. Ekhokardiografi Endokardiosis Penyakit Katup Mitral Jantung Anjing (ECHOCARDIOGRAPHY OF ENDOCARDIOSIS MITRAL VALVE HEART DISEASE IN DOGS

    Directory of Open Access Journals (Sweden)

    Deni Noviana

    2013-08-01

    Full Text Available Endocardiosis is a disease commonly found in Pomeranian dog characterized by progressive myxomatousdegeneration of the atrio-ventricular valves especially in the mitral valve. The purpose of this study was todefine the diagnose and severeity of this disease on the Pomeranian by using brightness mode, motion mode,dan color flow Doppler echocardiography technique. Echocardiography was performed on 8 Pomeranianconsisting of 6 males and 2 females with age range of 2-14 years. Brightness mode echocardiography wasused to see the echotexture of endocardium, mitral valve, and the valve movement. The results showedendocardium thickening, along with chronic fibrosis and nodular thickening of the anterior and posteriormitral valve leaflet. Three out of seven cases showed prolapsed of the mitral valve. Motion modeechocardiography was performed in order to measure left ventricle internal dimension, myocardium thickness,fractional shortening, left atrial and aortic dimension. The results showed myocardium thickening, alongwith left atrial enlargement. Color flow Doppler echocardiography was used to confirm the mitral valveregurgitation. Three of seven cases showed the presence of regurgitation signed by turbulence color of theprolapsed mitral valve. Based on the degree of severity, scoring system used in this study, endocardiosis canbe divided into three types that are mild, moderate and severe.

  1. Assessment of quantitative hypertrophy scores in hypertrophic cardiomyopathy : Magnetic resonance imaging versus echocardiography

    NARCIS (Netherlands)

    Posma, JL; Blanksma, PK; vanderWall, EE; Hamer, HPM; Mooyaart, EL; Lie, KI

    1996-01-01

    To compare the diagnostic value of spin-echo magnetic resonance (MR) imaging and transthoracic echocardiography in quantitative assessment of the extent of hypertrophy in patients with hypertrophic cardiomyopathy (HCM), we examined 52 consecutive patients with HCM. The Spirito-Maron and Wigle hypert

  2. Assessment of myocardial strain and strain rate by tissue doppler echocar-diography

    Directory of Open Access Journals (Sweden)

    Ekimova N.A.

    2013-03-01

    Full Text Available The objective of the article is to review the current data on the method of quantitative evaluation of cardiac mechanics — assessment of myocardial strain and strain rate according to the results of the tissue Doppler echocardiography and prospects of its clinical application.

  3. The influence of transoesophageal echocardiography on intra-operative decision making - A European multicentre study

    NARCIS (Netherlands)

    Kolev, N; Brase, R; Swanevelder, J; Oppizzi, M; Riesgo, MJ; van der Maaten, JMAA; Abiad, MG; Guarracino, F; Zimpfer, M

    1998-01-01

    The role of transoesophageal echocardiography (TOE) in anaesthesia remains controversial because it is a rapidly evolving technique with few proven benefits and considerable cost. Recently, the Society of Cardiovascular Anaesthesiologists has published practice guidelines for the use of peri-operati

  4. Influence of arterial compliance on presence and extent of ischaemia during stress echocardiography

    Science.gov (United States)

    Haluska, B A; Matthys, K; Fathi, R; Rozis, E; Carlier, S G; Marwick, T H

    2006-01-01

    Objective To seek an association between total arterial compliance (TAC) and the extent of ischaemia at stress echocardiography. Design Cohort study. Setting Regional cardiac centre. Methods 255 consecutive patients (147 men; mean (SD) age 58 (8)) presenting for stress echocardiography for clinical indications were studied. Wall motion score index (WMSI) was calculated and ischaemia was defined by an inducible or worsening wall motion abnormality. Peak WMSI was used to reflect the extent of dysfunction (ischaemia or scar), and ΔWMSI was indicative of extent of ischaemia. TAC was assessed at rest by simultaneous radial applanation tonometry and pulsed wave Doppler in all patients. Results Ischaemia was identified by stress echocardiography in 65 patients (25%). TAC was similar in the groups with negative and positive echocardiograms (1.08 (0.41) v 1.17 (0.51) ml/mm Hg, not significant). However, the extent of dysfunction was associated with TAC independently of age, blood pressure, risk factors, and use of a β blocker. Moreover, the extent of ischaemia was determined by TAC, risk factors, and use of a β blocker. Conclusion While traditional cardiovascular risk factors are strong predictors of ischaemia on stress echocardiography, TAC is an independent predictor of the extent of ischaemia. PMID:16365349

  5. A maximum likelihood approach to diffeomorphic speckle tracking for 3D strain estimation in echocardiography

    NARCIS (Netherlands)

    A.H. Curiale (Ariel H.); G. Vegas-Sanchez-Ferrero (Gonzalo); J.G. Bosch (Hans); S. Aja-Fernández (Santiago)

    2015-01-01

    textabstractThe strain and strain-rate measures are commonly used for the analysis and assessment of regional myocardial function. In echocardiography (EC), the strain analysis became possible using Tissue Doppler Imaging (TDI). Unfortunately, this modality shows an important limitation: the angle

  6. Acute myocarditis with normal wall motion detected with 2D speckle tracking echocardiography

    Directory of Open Access Journals (Sweden)

    Thomas Sturmberger

    2016-05-01

    Full Text Available We present the case of a 26-year-old male with acute tonsillitis who was referred for coronary angiography because of chest pain, elevated cardiac biomarkers, and biphasic T waves. The patient had no cardiovascular risk factors. Echocardiography showed no wall motion abnormalities and no pericardial effusion. 2D speckle tracking revealed distinct decreased regional peak longitudinal systolic strain in the lateral and posterior walls. Ischemic disease was extremely unlikely in view of his young age, negative family history regarding coronary artery disease, and lack of regional wall motion abnormalities on the conventional 2D echocardiogram. Coronary angiography was deferred as myocarditis was suspected. To confirm the diagnosis, cardiac magnetic resonance tomography (MRT was performed, showing subepicardial delayed hyperenhancement in the lateral and posterior walls correlating closely with the strain pattern obtained by 2D speckle tracking echocardiography. With a working diagnosis of acute myocarditis associated with acute tonsillitis, we prescribed antibiotics and nonsteroidal anti-inflammatory drugs. The patient’s clinical signs resolved along with normalization of serum creatine kinase (CK levels, and the patient was discharged on the third day after admission. Learning points: • Acute myocarditis can mimic acute coronary syndromes. • Conventional 2D echocardiography lacks specific features for detection of subtle regional wall motion abnormalities. • 2D speckle tracking expands the scope of echocardiography in identifying myocardial dysfunction derived from edema in acute myocarditis.

  7. Evaluation of Subclinical Left Ventricular Systolic Dysfunction in Chronic Asymptomatic Alcoholics by Speckle Tracking Echocardiography

    Directory of Open Access Journals (Sweden)

    Murathan Kucuk

    2017-01-01

    Full Text Available By using two-dimensional speckle tracking echocardiography, we aimed to investigate the structural and functional changes on myocardium in chronic asymptomatic alcoholics without any cardiovascular disease. Forty-one consecutive asymptomatic male alcoholics who were admitted to the outpatient alcoholism unit and 30 age matched healthy male volunteers selected as the control group were enrolled in the study. The study group were investigated by using standard two-dimensional echocardiography and speckle tracking echocardiography. The left ventricular (LV global longitudinal strain and LV global circumferential strain were significantly lower in alcoholics when compared with control subjects. There was no difference in global radial strain between the two groups. To demonstrate the effect of total life time dose of ethanol (TLDE on echocardiographic abnormalities, we assessed the correlation analysis. There was a nonsignificant weak correlation between global LV circumferential strain and TLDE (r=0.27, p=0.083. Speckle tracking echocardiography derived left ventricular systolic function was impaired in chronic alcoholic patients when compared with healthy controls.

  8. Cardiovascular Complications in Chronic Obstructive Pulmonary Disease with Reference to 2D Echocardiography Findings

    Directory of Open Access Journals (Sweden)

    Vikram B Vikhe

    2013-08-01

    Results: Emphysema and chronic bronchitis was present in 38% and 62% respectively. Echocardiographic evidence of cor-pulmonale and pulmonary hypertension was found in 70% of the patients. Conclusions: Echocardiography is more sensitive than electrocardiography in detecting PAH and right ventricular dysfunction in COPD. [Natl J Med Res 2013; 3(4.000: 385-388

  9. Comparison of magnetic resonance imaging and echocardiography in determination of cardiac dimensions in normal subjects.

    Science.gov (United States)

    Friedman, B J; Waters, J; Kwan, O L; DeMaria, A N

    1985-06-01

    No data exist regarding the ability of magnetic resonance imaging to assess cardiac size and performance in human beings. Therefore, measurements of cardiac dimensions by magnetic resonance imaging were compared with those obtained by two-dimensional echocardiography in 21 normal subjects. Magnetic resonance transverse cardiac sections were obtained during electrocardiographic gating using a spin echo pulse sequence. In normal subjects, magnetic resonance imaging yielded a range of values for cardiac dimensions having a similar standard deviation as that of two-dimensional echocardiography. Diastolic measurements of the aorta, left atrium, left ventricle and septum obtained by magnetic resonance imaging correlated well with those obtained by two-dimensional echocardiography (r = 0.82, 0.78, 0.81 and 0.75, respectively). The correlation coefficient of r = 0.35 observed for the posterior wall thickness was not surprising in view of the narrow range of normal values. Only a general correlation (r = 0.53) existed for the right ventricular diastolic dimension; this was probably related to the difficulty in obtaining representative measurements due to the complex geometry of this chamber. Failure of systolic dimension measurements by magnetic resonance imaging to correlate with those obtained by echocardiography is probably related to limitations of electrocardiographic gating, especially of determining the exact end-systolic frame. Although technically complex at present, magnetic resonance imaging does provide an additional noninvasive technique for measurement of cardiac size.

  10. Comparison of septal strain patterns in dyssynchronous heart failure between speckle tracking echocardiography vendor systems

    NARCIS (Netherlands)

    van Everdingen, Wouter M; Paiman, Marie-Louise; van Deursen, Caroline J M; Cramer, MJ; Vernooy, Kevin; Delhaas, Tammo; Prinzen, Frits W

    2015-01-01

    AIM: To analyze inter-vendor differences of speckle tracking echocardiography (STE) in imaging cardiac deformation in patients with dyssynchronous heart failure. METHODS AND RESULTS: Eleven patients (all with LBBB, median age 60.7 years, 9 males) with implanted cardiac resynchronization therapy devi

  11. A maximum likelihood approach to diffeomorphic speckle tracking for 3D strain estimation in echocardiography

    NARCIS (Netherlands)

    A.H. Curiale (Ariel H.); G. Vegas-Sanchez-Ferrero (Gonzalo); J.G. Bosch (Johan); S. Aja-Fernández (Santiago)

    2015-01-01

    textabstractThe strain and strain-rate measures are commonly used for the analysis and assessment of regional myocardial function. In echocardiography (EC), the strain analysis became possible using Tissue Doppler Imaging (TDI). Unfortunately, this modality shows an important limitation: the angle b

  12. Modified transesophageal echocardiography of the dissected thoracic aorta; A novel diagnostic approach

    NARCIS (Netherlands)

    Jansen Klomp, Wouter W.; Peelen, Linda M.; Brandon Bravo Bruinsma, George J.; Van'T Hof, Arnoud W J; Grandjean, Jan G.; Nierich, Arno P.

    2016-01-01

    Background: Transesophageal echocardiography (TEE) is a key diagnostic modality in patients with acute aortic dissection, yet its sensitivity is limited by a "blind-spot" caused by air in the trachea. After placement of a fluid-filled balloon in the trachea visualization of the thoracic aorta become

  13. The role of echocardiography in Staphylococcus aureus bacteraemia at Auckland City Hospital.

    Science.gov (United States)

    Gow, Nicholas; Lowe, Boris S; Freeman, Joshua; Roberts, Sally

    2015-06-12

    Current guidelines recommend echocardiography in all episodes of Staphylococcus aureus bacteraemia (SAB). This study aimed to determine whether a very low-risk group of patients with SAB could be found in whom echocardiography was of no incremental diagnostic value for the diagnosis of infective endocarditis. Using the ANZCOSS dataset, we identified 574 eligible episodes of adult SAB at Auckland District Health Board (ADHB) between 2007 and 2012, and retrospectively obtained additional microbiological and clinical data. Prevalence of IE was determined using the modified Duke's criteria for diagnosis of IE. Multivariate logistic regression analysis was used to determine whether risk factors were independently associated with IE, and we also assessed their negative predictive value (NPV). Transthoracic and/or transoesophageal echocardiography was performed in 370 (65%) episodes of SAB. The prevalence of clinically definite and clinically possible IE was 5.6% and 8.5%, respectively. Thirty day all-cause mortality was 11.7%. The factors with the highest NPV when absent in hospital-acquired SAB were non central venous line-associated bacteraemia (100%), persistent bacteraemia (96%), and presence of a prosthetic valve or cardiac rhythm management (CRM) device (95%). When none of these three criteria were present the NPV was 100% (99-100%). A group of very low risk patients was found in our study: central line-associated SAB without prosthetic valves / CRM devices and without persistent bacteraemia. These patients had no episodes of IE and echocardiography is of no incremental diagnostic benefit.

  14. Dynamic three-dimensional reconstruction of the heart by transesophageal echocardiography

    Directory of Open Access Journals (Sweden)

    Veiga Maria de Fátima

    1999-01-01

    Full Text Available OBJECTIVE: To evaluate echocardiography accuracy in performing and obtaining images for dynamical three-dimensional (3D reconstruction. METHODS: Three-dimensional (3D image reconstruction was obtained in 20 consecutive patients who underwent transesophageal echocardiography. A multiplanar 5 MHz transducer was used for 3D reconstruction. RESULTS: Twenty patients were studied consecutively. The following cardiac diseases were present: valvar prostheses-6 (2 mitral, 2 aortic and 2 mitral and aortic; mitral valve prolapse- 3; mitral and aortic disease - 2; aortic valve disease- 5; congenital heart disease- 3 (2 atrial septal defect- ASD - and 1 transposition of the great arteries -TGA; arteriovenous fistula- 1. In 7 patients, color Doppler was also obtained and used for 3D flow reconstruction. Twenty five cardiac structures were acquired and 60 reconstructions generated (28 of mitral valves, 14 of aortic valves, 4 of mitral prostheses, 7 of aortic prostheses and 7 of the ASD. Fifty five of 60 (91.6% reconstructions were considered of good quality by 2 independent observers. The 11 reconstructed mitral valves/prostheses and the 2 reconstructed ASDs provided more anatomical information than two dimensional echocardiography (2DE alone. CONCLUSION: 3D echocardiography using a transesophageal transducer is a feasible technique, which improves detection of anatomical details of cardiac structures, particularly of the mitral valve and atrial septum.

  15. Assessment of quantitative hypertrophy scores in hypertrophic cardiomyopathy : Magnetic resonance imaging versus echocardiography

    NARCIS (Netherlands)

    Posma, JL; Blanksma, PK; vanderWall, EE; Hamer, HPM; Mooyaart, EL; Lie, KI

    1996-01-01

    To compare the diagnostic value of spin-echo magnetic resonance (MR) imaging and transthoracic echocardiography in quantitative assessment of the extent of hypertrophy in patients with hypertrophic cardiomyopathy (HCM), we examined 52 consecutive patients with HCM. The Spirito-Maron and Wigle hypert

  16. Gunshot-Induced Aorto-Left Atrial Fistula Diagnosed by Intraoperative Transesophageal Echocardiography.

    Science.gov (United States)

    Nandate, Koichiro; Krishnamoorthy, Vijay; McIntyre, Lisa K; Verrier, Edward D; Mackensen, G Burkhard

    2016-02-01

    Aorto-left atrial fistula (AAF) is rarely encountered in clinical practice, and the early diagnosis can be very challenging. This report describes a unique case of AAF caused by a gunshot injury and the pivotal role of transesophageal echocardiography for diagnosis and assessment.

  17. Effect of Jaw Thrust on Transesophageal Echocardiography Probe Insertion and Concomitant Oropharyngeal Injury.

    Science.gov (United States)

    Chang, Jee-Eun; Min, Seong-Won; Kim, Chong-Soo; Lee, Jung-Man; No, Hyunjoung; Hwang, Jin-Young

    2015-10-01

    The aim of this study was to evaluate the effect of jaw thrust on transesophageal echocardiography probe insertion and concomitant oropharyngeal injury. A prospective, randomized study Medical center governed by a university hospital Forty-two adult patients undergoing cardiovascular surgery were included. After the induction of anesthesia, a transesophageal echocardiography probe was inserted using an anterior jaw lift technique (conventional group, n = 21) or a jaw thrust-assisted technique (jaw thrust group, n = 21). The incidence of oropharyngeal injury, number of insertion attempts, blood on the probe tip, and presence of persistent oropharyngeal bleeding were evaluated. In the conventional group, oropharyngeal injury occurred more frequently than in the jaw-thrust group (52.4% v 9.5%, respectively; p = 0.006). Regarding transesophageal echocardiography probe insertion, the conventional group required more attempts than the jaw-thrust group (p = 0.043). The incidence of blood on the probe tip was higher in the conventional group than in the jaw-thrust group (p = 0.020), but the presence of persistent oropharyngeal bleeding was similar between the 2 groups. The jaw-thrust maneuver facilitated the insertion of the transesophageal echocardiography probe and reduced concomitant oropharyngeal injury. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. [Digital revolution in the echocardiography laboratory. Current status and future perspectives] .

    Science.gov (United States)

    Badano, L P; Di Chiara, A; Werren, M; Sabbadini, C; Fioretti, P M

    2000-12-01

    Echocardiography is changing from an operative modality in which most images are stored in analog fashion on videotape into one with most data stored digitally. This transition is accelerating today, fueled by several factors. First, there is widespread recognition of the value of digital storage of echocardiograms, including random access to studies as well as to images within a study, side-by-side comparison with prior studies, easier quantification, and multiplication and remote transmission of images without degradation. Second, continuous improvement of the cost/performance ratio of modern computers makes routine digital echocardiography both feasible and affordable. Finally, the formulation and acceptance within the industry of the DICOM image formatting standard for echocardiography. The acceptance of this standard allows the echo-labs around the world to be free to choose individual echo-machines on the basis of their individual merits for their laboratories with the assurance that these machines will be able to communicate with each other by an internationally agreed upon standard. Advantages of digital echocardiography are overwhelming and there is little doubt that this approach will be essential for the proper utilization of this technique. The technology will undoubtedly continue to change. Those who are waiting for it to be perfected may be waiting for a long time.

  19. Is pre-discharge echocardiography indicated for asymptomatic neonates with a heart murmur? A retrospective analysis.

    Science.gov (United States)

    Al-Ammouri, Iyad; Ayoub, Fares; Dababneh, Rima

    2016-08-01

    The purpose of this study was to determine whether a murmur detected on routine pre-discharge examination of asymptomatic newborn children in the first 48 hours of life warrants further investigation with echocardiography. We conducted a retrospective review of all echocardiography studies of neonates born at Jordan University Hospital between August, 2007 and June, 2014. Findings on physical examination as well as the indication of the echocardiographic studies were reviewed. We included asymptomatic neonates for whom echocardiographic studies were carried out due to the sole indication of a heart murmur on routine pre-discharge neonatal physical examination. Of 309 asymptomatic newborns with murmurs on pre-discharge examination, echocardiography revealed 68 (22%) cases of CHD, with 18 (6%) designated as significant heart disease with anticipated intervention during infancy or childhood. The most common abnormality was ventricular septal defect occurring in 36 cases. Critical heart diseases detected included hypoplastic left heart syndrome in two and aortic valve stenosis in four newborns. Although most asymptomatic neonates with heart murmurs have normal hearts, a small percentage may have significant heart disease. The decision to refer an asymptomatic newborn with a murmur for echocardiography before discharge from the hospital remains controversial and must be supported by other evidence such as murmur characteristics and local trends in parental compliance with follow-up well-baby visits.

  20. Incremental Value of Three-Dimensional Transesophageal Echocardiography over the Two-Dimensional Technique in the Assessment of a Thrombus in Transit through a Patent Foramen Ovale.

    Science.gov (United States)

    Thind, Munveer; Ahmed, Mustafa I; Gok, Gulay; Joson, Marisa; Elsayed, Mahmoud; Tuck, Benjamin C; Townsley, Matthew M; Klas, Berthold; McGiffin, David C; Nanda, Navin C

    2015-05-01

    We report a case of a right atrial thrombus traversing a patent foramen ovale into the left atrium, where three-dimensional transesophageal echocardiography provided considerable incremental value over two-dimensional transesophageal echocardiography in its assessment. As well as allowing us to better spatially characterize the thrombus, three-dimensional transesophageal echocardiography provided a more quantitative assessment through estimation of total thrombus burden.