WorldWideScience

Sample records for achromatic lesions

  1. The Achromatic Interfero Coronagraph

    Rabbia, Yves; Rivet, Jean-Pierre

    2007-01-01

    We report on the Achromatic Interfero Coronagraph, a focal imaging device which aims at rejecting the energy contribution of a point-like source set on-axis, so as to make detectable its angularly-close environment (applicable to stellar environment: circumstellar matter, faint companions, planetary systems, but also conceivably to Active Galatic Nucleii and multiple asteroids). With AIC, starlight rejection is based on destructive interference, which allows exploration of the star's neighbouring at angular resolution better than the diffraction limit of the hosting telescope. Thanks to the focus crossing property of light, rejection is achromatic thus yielding a large spectral bandwidth of work. Descriptions and comments are given regarding the principle, the device itself, the constraints and limitations, and the theoretical performance. Results are presented which demonstrate the close-sensing capability and which show images of a companion obtained in laboratory and 'on the sky' as well. A short pictorial...

  2. The Achromatic Interfero Coronagraph

    Rabbia, Yves; Gay, Jean; Rivet, Jean-Pierre

    2007-01-01

    We report on the Achromatic Interfero Coronagraph, a focal imaging device which aims at rejecting the energy contribution of a point-like source set on-axis, so as to make detectable its angularly-close environment (applicable to stellar environment: circumstellar matter, faint companions, planetary systems, but also conceivably to Active Galatic Nucleii and multiple asteroids). With AIC, starlight rejection is based on destructive interference, which allows exploration of the star's neighbou...

  3. The Achromatic Interfero Coronagraph

    Rabbia, Yves; Gay, Jean; Rivet, Jean-Pierre

    2007-04-01

    We report on the Achromatic Interfero Coronagraph, a focal imaging device which aims at rejecting the energy contribution of a point-like source set on-axis, so as to make detectable its angularly-close environment (applicable to stellar environment: circumstellar matter, faint companions, planetary systems, but also conceivably to Active Galactic Nucleii and multiple asteroïds). With AIC, starlight rejection is based on destructive interference, which allows exploration of the star's neighbourhood at an angular resolution better than the diffraction limit of the hosting telescope. Thanks to the focus crossing property of light, rejection is achromatic thus yielding a large spectral bandwidth of work. Descriptions and comments are given regarding the principle, the device itself, the constraints and limitations, and the theoretical performance. Results are presented which demonstrate the close-sensing capability and which show images of a companion obtained in laboratory and ‘on the sky’ as well. A short pictorial description of the alternative AIC concepts, CIAXE and Open-Air CIAXE, currently under study, is given. To cite this article: Y. Rabbia et al., C. R. Physique 8 (2007).

  4. Achromatic optical diode in fiber optics

    Berent, Michal; Vitanov, Nikolay V

    2013-01-01

    We propose a broadband optical diode, which is composed of one achromatic reciprocal quarter-wave plate and one non-reciprocal quarter-wave plate, both placed between two crossed polarizers. The presented design of achromatic wave plates relies on an adiabatic evolution of the Stokes vector, thus, the scheme is robust and efficient. The possible simple implementation using fiber optics is suggested.

  5. Achromatic and Uncoupled Medical Gantry

    Tsoupas, N.; Kayran, D.; Litvinenko, V.

    One of the functions of a medical gantry is to irradiate a tumor from different angles to reduce the dose received by the healthy tissue which surrounds the tumor. The rotation of the gantry rotates also its quadrupoles that focus the beam, as a result the beam is "coupled" in the sense that the horizontal motion of the beam particles is affected by the vertical motion and vice-versa therefore the beam spot size at the tumor may vary with the angular orientation of the gantry. Although such a beam-coupling is inevitable in a rotated gantry in which the horizontal plane is not the symmetry plane of the quadrupoles, it is possible to find a solution that the optics of the gantry"appears uncoupled" at any angular orientation of the gantry. As we show in the paper, the condition of an uncoupled gantry is equivalent to an uncoupled linear-beam-transport-matrix which is independent of the angular orientation of the gantry, therefore the beam spot size at the location of the tumor is independent of the orientation of the gantry. In this paper we present the theoretical basis to generate the beam optics for a gantry which is constrained to provide uncoupled and also achromatic beamtransport to the location of the tumor. In addition we present the layout of the magnetic elements and the optics of a medical gantrywhich satisfies the achromaticity and uncoupled conditions.

  6. Tunable Achromats and CLIC Applications

    D'Amico, T E

    2000-01-01

    It is imperative for linear colliders that the bunch length be adjustable. In most cases bunch compression is required, but recently, in the design of the Compact LInear Collider (CLIC) RF Power Source, it was shown that bunch stretching may also be necessary. In some situations, both modes may be needed, which implies the need for tunable magnetic insertions. This is even more essential in a test facility, to span a wide experimental range. In addition, flexible tuning provides a better control of the stability of an isochronous insertion. To start a numerical search for a tunable insertion from scratch is very uncertain because the related phase space is very uneven. However, a starting point obtained with an analytical approximation is often sufficient to ensure convergence. Another advantage of the analytical treatment described in this paper is that it sheds light on the shape of the entire phase space. To achieve this the isochronous achromat developed previously has been given tuning capabilities by ex...

  7. Diffraction theory for an achromatic Fourier transformation

    A three-lens achromatic Fourier transform system is analyzed in the contex of parazial Fresnel diffraction theory. From the analysis a general solution for the required wavelength dependence of the various lenses is found. A particular arrangement of the general system is then considered. Using first-order lens design principles, it is shown that each dispersive lens cand be fabricated using a holographic zone lens and glas element cascade. The parazial chromatic aberrations of the resulting system are calculated. It is found that this system design yields an achromatic transformation that is well corrected (parazially) over the entire visible spectrum

  8. Achromatic Breaks for Swift GRBs: Any Evidence?

    S. Covino(INAF - Oss. Astronomico di Brera); Malesani, D.; Tagliaferri, G.; Vergani, S.D.; Chincarini, G.; Kann, D. A.; A. Moretti(Fermilab, Batavia, IL, USA); Stella, L.

    2006-01-01

    The availability of multi-wavelength high-quality data of gamma-ray burst afterglows in the Swift era, contrary to the expectations, did not allow us to fully confirm yet one of the most fundamental features of the standard afterglow picture: the presence of an achromatic break in the decaying light curve. We briefly review the most interesting cases identified so far.

  9. Achromatic X-ray lenses; Achromatische Roentgenlinsen

    Umbach, Marion

    2009-07-01

    This thesis presents first results on the development of achromatic refractive X-ray lenses which can be used for scientific experiments at synchrotron sources. First of all the different requirements for achromatic X-ray lenses have been worked out. There are different types of lenses, one type can be used for monochromatized sources when the energy is scanned while the spot size should be constant. The other type can be used at beamlines providing a broad energy band. By a combination of focusing and defocusing elements we have developed a lens system that strongly reduces the chromatic aberration of a refractive lens in a given energy range. The great challenge in the X-ray case - in contrast to the visible range - the complex refractive index, which is very similar for the possible materials in the X-ray spectrum. For precise studies a numerical code has been developed, which calculates the different rays on their way through the lenses to the detector plane via raytracing. In this numerical code the intensity distribution in the detector plane has been analyzed for a chromatic and the corresponding achromatic system. By optimization routines for the two different fields of applications specific parameter combinations were found. For the experimental verification an achromatic system has been developed, consisting of biconcave SU-8 lenses and biconvex Nickel Fresnel lenses. Their fabrication was based on the LIGA-process, including a further innovative development, namely the fabrication of two different materials on one wafer. In the experiment at the synchrotron source ANKA the energy was varied in a specific energy range in steps of 0.1 keV. The intensity distribution for the different energies was detected at a certain focal length. For the achromatic system a reduction of the chromatic aberration could be clearly shown. Achromatic refractive X-ray lenses, especially for the use at synchrotron sources, have not been developed so far. As a consequence of the

  10. Analytic second- and third-order achromat designs

    An achromat is a transport system that carries a beam without distorting its transverse phase space distribution. In this study, we apply the Lie algebraic technique to a repetitive FODO array to make it either a second-order or a third-order achromat. (Achromats based on reflection symmetries are not studied here.) We consider third-order achromats whose unit FODO cell layout is shown. The second-order achromat layout is the same, except the octupoles are absent. For the second-order achromats, correction terms (due to the finite bending of the dipoles) to the well-known formulae for the sextupole strengths are derived. For the third-order achromats, analytic expressions for the five octupole strengths are given. The quadrupole, sextupole and octupole magnets are assumed to be thin-lens elements. The dipoles are assumed to be sector magnets filling the drift spaces. More details of the analysis have been reported elsewhere

  11. Adjustable hybrid diffractive/refractive achromatic lens

    Valley, Pouria; Savidis, Nickolaos; Schwiegerling, Jim; Dodge, Mohammad Reza; Peyman, Gholam; N. Peyghambarian

    2011-01-01

    We demonstrate a variable focal length achromatic lens that consists of a flat liquid crystal diffractive lens and a pressure-controlled fluidic refractive lens. The diffractive lens is composed of a flat binary Fresnel zone structure and a thin liquid crystal layer, producing high efficiency and millisecond switching times while applying a low ac voltage input. The focusing power of the diffractive lens is adjusted by electrically modifying the sub-zones and re-establishing phase wrapping po...

  12. Achromatic optical correlator for white light pattern recognition

    Chao, Tien-Hsin; Liu, Hua-Kuang; Chen, Ming; Cai, Luzhong

    1987-01-01

    An achromatic optical correlator using spatially multiplexed achromatic matched spatial filters (MSFs) for white light optical pattern recognition is presented. The MSF array is synthesizd using a monochromatic laser and its achromaticity is achieved by adjusting the scale and spatial carrier frequency of each MSF to accommodate the wavelength variations in white light correlation detections. Systems analysis and several experimental results showing the correlation peak intensity using white-light illumination are presented.

  13. Integrated Optics Achromatic Nuller for Stellar Interferometry

    Ksendzov, Alexander

    2012-01-01

    This innovation will replace a beam combiner, a phase shifter, and a mode conditioner, thus simplifying the system design and alignment, and saving weight and space in future missions. This nuller is a dielectric-waveguide-based, four-port asymmetric coupler. Its nulling performance is based on the mode-sorting property of adiabatic asymmetric couplers that are intrinsically achromatic. This nuller has been designed, and its performance modeled, in the 6.5-micrometer to 9.25-micrometer spectral interval (36% bandwidth). The calculated suppression of starlight for this 15-cm-long device is 10(exp -5) or better through the whole bandwidth. This is enough to satisfy requirements of a flagship exoplanet-characterization mission. Nulling interferometry is an approach to starlight suppression that will allow the detection and spectral characterization of Earth-like exoplanets. Nulling interferometers separate the light originating from a dim planet from the bright starlight by placing the star at the bottom of a deep, destructive interference fringe, where the starlight is effectively cancelled, or nulled, thus allowing the faint off-axis light to be much more easily seen. This process is referred to as nulling of the starlight. Achromatic nulling technology is a critical component that provides the starlight suppression in interferometer-based observatories. Previously considered space-based interferometers are aimed at approximately 6-to-20-micrometer spectral range. While containing the spectral features of many gases that are considered to be signatures of life, it also offers better planet-to-star brightness ratio than shorter wavelengths. In the Integrated Optics Achromatic Nuller (IOAN) device, the two beams from the interferometer's collecting telescopes pass through the same focusing optic and are incident on the input of the nuller.

  14. Achromatic beam transport of High Current Injector

    Kumar, Sarvesh; Mandal, A.

    2016-02-01

    The high current injector (HCI) provides intense ion beams of high charge state using a high temperature superconducting ECR ion source. The ion beam is accelerated upto a final energy of 1.8 MeV/u due to an electrostatic potential, a radio frequency quadrupole (RFQ) and a drift tube linac (DTL). The ion beam has to be transported to superconducting LINAC which is around 50 m away from DTL. This section is termed as high energy beam transport section (HEBT) and is used to match the beam both in transverse and longitudinal phase space to the entrance of LINAC. The HEBT section is made up of four 90 deg. achromatic bends and interconnecting magnetic quadrupole triplets. Two RF bunchers have been used for longitudinal phase matching to the LINAC. The ion optical design of HEBT section has been simulated using different beam dynamics codes like TRACEWIN, GICOSY and TRACE 3D. The field computation code OPERA 3D has been utilized for hardware design of all the magnets. All the dipole and quadrupole magnets have been field mapped and their test results such as edge angles measurements, homogeneity and harmonic analysis etc. are reported. The whole design of HEBT section has been performed such that the most of the beam optical components share same hardware design and there is ample space for beam diagnostics as per geometry of the building. Many combination of achromatic bends have been simulated to transport the beam in HEBT section but finally the four 90 deg. achromatic bend configuration is found to be the best satisfying all the geometrical constraints with simplified beam tuning process in real time.

  15. Achromatic THz absorption of conductive nanofilms

    Qiang Yin

    2015-10-01

    Full Text Available According to the theory, an ultrathin conductive film can achromatically dissipate electromagnetic waves with frequency ranging from radio to terahertz. A moderate absorption effect, which gives rise to a maximal absorbance of 50%, can be found if an impedance matching condition is satisfied. We have experimentally demonstrated the frequency-irrelevant, maximal absorption by employing a conductive nanofilm and launching terahertz waves at Brewster angle when the sheet (square resistance of the film meets the impedance matching condition. In the entire terahertz spectral range covered by our experiments, the frequency-independent optical properties were consistent with the theoretical calculations.

  16. An analytical study of double bend achromat lattice

    Fakhri, Ali Akbar, E-mail: fakhri@rrcat.gov.in; Kant, Pradeep; Singh, Gurnam; Ghodke, A. D. [Raja Ramanna Centre for Advanced Technology, Indore 452 013 (India)

    2015-03-15

    In a double bend achromat, Chasman-Green (CG) lattice represents the basic structure for low emittance synchrotron radiation sources. In the basic structure of CG lattice single focussing quadrupole (QF) magnet is used to form an achromat. In this paper, this CG lattice is discussed and an analytical relation is presented, showing the limitation of basic CG lattice to provide the theoretical minimum beam emittance in achromatic condition. To satisfy theoretical minimum beam emittance parameters, achromat having two, three, and four quadrupole structures is presented. In this structure, different arrangements of QF and defocusing quadruple (QD) are used. An analytical approach assuming quadrupoles as thin lenses has been followed for studying these structures. A study of Indus-2 lattice in which QF-QD-QF configuration in the achromat part has been adopted is also presented.

  17. An analytical study of double bend achromat lattice

    In a double bend achromat, Chasman-Green (CG) lattice represents the basic structure for low emittance synchrotron radiation sources. In the basic structure of CG lattice single focussing quadrupole (QF) magnet is used to form an achromat. In this paper, this CG lattice is discussed and an analytical relation is presented, showing the limitation of basic CG lattice to provide the theoretical minimum beam emittance in achromatic condition. To satisfy theoretical minimum beam emittance parameters, achromat having two, three, and four quadrupole structures is presented. In this structure, different arrangements of QF and defocusing quadruple (QD) are used. An analytical approach assuming quadrupoles as thin lenses has been followed for studying these structures. A study of Indus-2 lattice in which QF-QD-QF configuration in the achromat part has been adopted is also presented

  18. An analytical study of double bend achromat lattice

    Fakhri, Ali Akbar; Kant, Pradeep; Singh, Gurnam; Ghodke, A. D.

    2015-03-01

    In a double bend achromat, Chasman-Green (CG) lattice represents the basic structure for low emittance synchrotron radiation sources. In the basic structure of CG lattice single focussing quadrupole (QF) magnet is used to form an achromat. In this paper, this CG lattice is discussed and an analytical relation is presented, showing the limitation of basic CG lattice to provide the theoretical minimum beam emittance in achromatic condition. To satisfy theoretical minimum beam emittance parameters, achromat having two, three, and four quadrupole structures is presented. In this structure, different arrangements of QF and defocusing quadruple (QD) are used. An analytical approach assuming quadrupoles as thin lenses has been followed for studying these structures. A study of Indus-2 lattice in which QF-QD-QF configuration in the achromat part has been adopted is also presented.

  19. First multi-bend achromat lattice consideration

    The first proposed lattice for a ‘diffraction-limited light source’ is reported. This approach has now more or less been used for the MAX IV project. By the beginning of 1990, three third-generation synchrotron light sources had been successfully commissioned in Grenoble, Berkeley and Trieste (ESRF, ALS and ELETTRA). Each of these new machines reached their target specifications without any significant problems. In parallel, already at that time discussions were underway regarding the next generation, the ‘diffraction-limited light source (DLSR)’, which featured sub-nm rad electron beam emittance, photon beam brilliance exceeding 1022 and the potential to emit coherent radiation. Also, at about that time, a first design for a 3 GeV DLSR was developed, based on a modified multiple-bend achromat (MBA) design leading to a lattice with normalized emittance of ∊x = 0.5 nm rad. The novel feature of the MBA lattice was the use of seven vertically focusing bend magnets with different bending angles throughout the achromat cell to keep the radiation integrals and resulting beam emittance low. The baseline design called for a 400 m ring circumference with 12 straight sections of 6 m length. The dynamic aperture behaviour of the DLSR lattice was estimated to produce > 5 h beam lifetime at 100 mA stored beam current

  20. A near-infrared zero-order achromatic retarder

    Arijit Saha; Kallol Bhattacharya; Ajoy Kumar Chakraborty

    2011-10-01

    Phase retarders normally show strong wavelength dependence. Achromatic retarders which exhibit nearly identical characteristics over a wide wavelength spectrum is used in polychromatic light. The present investigation deals with a technique to design and study the characteristics of an achromatic combination of birefringent plates in 800–2000 nm range. The retarder has been designed using calcite, crystalline quartz and ADP. The thicknesses of the plates are 19.38 m, 446.14 m and 12.57 m respectively. The new arrangement of three birefringent plates proposed has the promise of producing a zero-order quarter wave achromatic combination with fairly good accuracy.

  1. Achromatic Metasurface Lens at Telecommunication Wavelengths.

    Khorasaninejad, Mohammadreza; Aieta, Francesco; Kanhaiya, Pritpal; Kats, Mikhail A; Genevet, Patrice; Rousso, David; Capasso, Federico

    2015-08-12

    Nanoscale optical resonators enable a new class of flat optical components called metasurfaces. This approach has been used to demonstrate functionalities such as focusing free of monochromatic aberrations (i.e., spherical and coma), anomalous reflection, and large circular dichroism. Recently, dielectric metasurfaces that compensate the phase dispersion responsible for chromatic aberrations have been demonstrated. Here, we utilize an aperiodic array of coupled dielectric nanoresonators to demonstrate a multiwavelength achromatic lens. The focal length remains unchanged for three wavelengths in the near-infrared region (1300, 1550, and 1800 nm). Experimental results are in agreement with full-wave simulations. Our findings are an essential step toward a realization of broadband flat optical elements. PMID:26168329

  2. Achromat with linear space charge for bunched beams

    The standard definition for an achromat is a transport line having zero values for the spatial dispersion (R16) and the angular dispersion (RZ6). For a bunched beam with linear space charge this definition of achromaticity does not hold. The linear space charge in the presence of a bend provides coupling between (a) bunch spatial width and bunch length (R1.5) and (b) bunch angular spread and bunch length (R25). Therefore, achromaticity should be redefined as a line having zero values of the spatial dispersion (R16), the angular dispersion (R26), and matrix elements R15 and R25. These additional conditions (R15=R25=0) can be achieved, for example, with two small RF cavities at appropriate locations in the achromat, to cancel space charge effects. An example of the application of this technique to the Spallation Neutron Source (SNS) high energy beam transport line is presented

  3. Achromatic Fresnel Lens with Improved Efficiency for PV Systems

    Mario González Montes; Juan Carlos Martínez-Antón; Daniel Vázquez Moliní; Antonio Álvarez Fernandez-Balbuena; Bernabeu, E.

    2014-01-01

    This work is aimed to design and evaluate different achromatic Fresnel lens solutions capable of operating as concentrators aimed at photovoltaic cells systems. Throughout this study, the theoretical parametric design of the achromatic lens will be shown together with a series of simulations to verify the performance of each lens topology. The results will be compared with a standard Fresnel lens to ascertain the validity and effectiveness of the obtained design. Finally, a novel kind of hybr...

  4. Principle of a coaxial Achromatic Interfero Coronagraph

    Gay, J.; Fressin, F.; Rivet, J.-P.

    We describe here the principle of a new type of coronagraph, based on the incident flux division with pupil reversal and phase shift on one beam, then recombination with destructive interferences at the center orf the field. This concept of nulling has already been used in the Interferometrical Achromatic Interfero-Coronagraph (AIC, Gay & Rabbia [CITE]), which lies on a Michelson interferometer interferomùetry which does not allow an easy insertion in the focal facility of a telescope. The variant under consideration has a completely coaxial design with an original and very compact optical combination. It is based upon two coaxial thick lenses in the same medium, stuck one to each other with a very narrow gap in between and a proper coating of the interfaces. The very geometry of the device ensures moreover the permanent and rigorous cophasing of the interferometer. The optical combination which fulfills this problem is unique and presents a range of properties which ease its insertion in the focal instrumentation of existing telescopes or next generation ones.

  5. Fully achromatic nulling interferometer (FANI) for high SNR exoplanet characterization

    Henault, Francois

    2015-01-01

    Space-borne nulling interferometers have long been considered as the best option for searching and characterizing extra-solar planets located in the habitable zone of their parent stars. Solutions for achieving deep starlight extinction are now numerous and well demonstrated. However they essentially aim at realizing an achromatic central null in order to extinguish the star. In this communication is described a major improvement of the technique, where the achromatization process is extended to the entire fringe pattern. Therefore higher Signal-to-noise ratios (SNR) and appreciable simplification of the detection system should result. The basic principle of this Fully achromatic nulling interferometer (FANI) consists in inserting dispersive elements along the arms of the interferometer. Herein this principle is explained and illustrated by a preliminary optical system design. The typical achievable performance and limitations are discussed and some initial tolerance requirements are also provided

  6. Design and laboratory demonstration of an achromatic vector vortex coronagraph.

    Murakami, Naoshi; Hamaguchi, Shoki; Sakamoto, Moritsugu; Fukumoto, Ryohei; Ise, Akitoshi; Oka, Kazuhiko; Baba, Naoshi; Tamura, Motohide

    2013-03-25

    A vector vortex coronagraph (VVC) is one of promising means for imaging extremely faint objects around bright stars such as exoplanets. We present a design of an achromatic VVC, in which an axially-symmetric half-wave plate (AHP) is placed between crossed polarization filters (circular polarizer and analyzer). The circular polarizer and the analyzer are both composed of a polarizer and a quarter-wave plate (QWP). We demonstrate, via Jones calculus and Fourier analysis, that the achromatic stellar elimination can theoretically be realized by optimal polarization filters, even when chromatic AHP and QWPs are used. We carried out laboratory demonstrations of the designed VVC using a photonic-crystal AHP. As a result, we observed achromatic coronagraphic performance, a light suppression level of 7 × 10(-5), over a wavelength from 543 nm to 633 nm. PMID:23546123

  7. Canonical description of a second-order achromat

    Kheifets, S.A.; Fieguth, T.H.; Ruth, R.D.

    1988-03-01

    Charged particle motion in second-order magnetic optical achromat is described using a canonical perturbation theory. Necessary and sufficient conditions for the existence of such a device are presented. Given these conditions, the second-order matrix elements at the end of the achromat are found explicity. It is shown that all geometric matrix elements are equal to zero and all chromatic matrix elements are either also equal to zero or proportional to the corresponding chromaticity. Thus all second-order matrix elements vanish simultaneously when the two chromaticities are made to be equal to zero 13 refs., 1 tab.

  8. An Investigation of the Eighteenth-Century Achromatic Telescope

    Jaecks, Duane H.

    2010-01-01

    The optical quality and properties of over 200 telescopes residing in museums and private collections have been measured and tested with the goal of obtaining new information about the early development of the achromatic lens (1757-1770). Quantitative measurements of the chromatic and spherical aberration of telescope objective lenses were made…

  9. Achromatic metasurface optical components by dispersive phase compensation

    Aieta, Francesco; Genevet, Patrice; Capasso, Federico

    2014-01-01

    The replacement of bulk refractive elements with flat ones enables the miniaturization of optical components required for integrated optical systems. This process comes with the limitation that planar optics suffers from large chromatic aberrations due to the dispersion of the phase accumulated by light during propagation. We show that this limitation can be overcome by compensating the dispersion of the propagation phase with the wavelength-dependent phase shift imparted by a metasurface. We demonstrate dispersion-free multi-wavelength dielectric metasurface deflectors in the near-infrared and design an achromatic flat lens in the same spectral region. Our design is based on low-loss coupled dielectric resonators, which introduce a dense spectrum of modes to enable dispersive phase compensation. Achromatic metasurfaces will find applications as multi-band-pass filters, lightweight collimators, and chromatically-corrected imaging lenses.

  10. Improved achromatization of phase mask coronagraphs using colored apodization

    N'Diaye, M; Cuevas, S; Soummer, R; Sánchez-Pérez, C; Zamkotsian, F

    2011-01-01

    For direct imaging of exoplanets, a stellar coronagraph helps to remove the image of an observed bright star by attenuating the diffraction effects caused by the telescope aperture of diameter D. The Dual Zone Phase Mask (DZPM) coronagraph constitutes a promising concept since it theoretically offers a small inner working angle (IWA \\sim \\lambda_0/D), good achromaticity and high starlight rejection, typically reaching a 1e6 contrast at 5 \\lambda_0/D from the star over a spectral bandwidth \\Delta\\lambda/\\lambda_0 of 25% (similar to H-band). This last value proves to be encouraging for broadband imaging of young and warm Jupiter-like planets. Contrast levels higher than 1e6 are however required for the observation of older and/or less massive companions over a finite spectral bandwidth. An achromatization improvement of the DZPM coronagraph is therefore mandatory to reach such performance. In its design, the DZPM coronagraph uses a grey (or achromatic) apodization. We propose to replace it by a colored apodizat...

  11. Improved achromatization of phase mask coronagraphs using colored apodization

    N'diaye, M.; Dohlen, K.; Cuevas, S.; Soummer, R.; Sánchez-Pérez, C.; Zamkotsian, F.

    2012-02-01

    Context. For direct imaging of exoplanets, a stellar coronagraph helps to remove the image of an observed bright star by attenuating the diffraction effects caused by the telescope aperture of diameter D. The dual zone phase mask (DZPM) coronagraph constitutes a promising concept since it theoretically offers a small inner working angle (IWA ~ λ0/D where λ0 denotes the central wavelength of the spectral range Δλ), good achromaticity, and high starlight rejection, typically reaching a 106 contrast at 5 λ0/D from the star over a spectral bandwidth Δλ/λ0 of 25% (similar to H-band). This last value proves to be encouraging for broadband imaging of young and warm Jupiter-like planets. Aims: Contrast levels higher than 106 are, however, required for observing older and/or less massive companions over a finite spectral bandwidth. An achromatization improvement of the DZPM coronagraph is therefore mandatory to reach such good performance. Methods: In its design, the DZPM coronagraph uses a gray (or achromatic) apodization. We replaced it by a colored apodization to increase the performance of this coronagraphic system over a wide spectral range. This innovative concept, called colored apodizer phase mask (CAPM) coronagraph, is defined to reach the highest contrast in the exoplanet search area. Once this has been done, we study the performance of the CAPM coronagraph in the presence of different errors to evaluate the sensitivity of our concept. Results: A 2.5 contrast gain is estimated from the performance provided by the CAPM coronagraph with respect to that of the DZPM coronagraph. A 2.2 × 10-8 intensity level at 5 λ0/D separation is then theoretically achieved with the CAPM coronagraph in the presence of a clear circular aperture and a 25% bandwidth. In addition, our studies show that our concept is less sensitive to low than to high-order aberrations for a given value of rms wavefront errors.

  12. Design of achromatic bending systems in the presence of space charge

    The usual conditions for achromaticity of a dispersive system are shown to be inadequate when space-charge effects are included. Using a matrix formulation describing linear space-charge forces, we give generalized criteria necessary for a system to be achromatic. Additionally, these conditions are necessary for conservation of transverse emittances. An example of such a system is given

  13. The Achromatic Telescopic Squeezing (ATS) MD part III

    Fartoukh, S; Goddard, B; Hofle, W; Jacquet, D; Kruk, G; Lamont, M; de Maria, R; Miyamoto, R; Mueller, G; Pojer, M; Ponce, L; Redaelli, S; Ryckx, N; Steinhagen, R; Strzelczyk, M; Vanbavinckhove, G; Wenninger, J

    2011-01-01

    This note highlights the results obtained during the third so-called ATS MD which took place in 2011. The goal of this MD was extremely challenging, targeting a pre-squeezed beta* of 40 cm in ATLAS and CMS, followed by a telescopic squeeze of these two insertions to finally reach a beta* of 10 cm both at IP1 and IP5. Due to the rather poor machine availability during the MD period, the time initially allocated to the ATS studies was hardly cut by a factor of 2, and "only" the achromatic pre-squeeze down to beta*=40 cm was demonstrated with beam.

  14. Multiplexing schemes for an achromatic programmable diffractive lens

    Millan, M S; Perez-Cabre, E; Oton, J [Technical University of Catalonia, Dep. Optics and Optometry, Terrassa-Barcelona, 08222 (Spain)], E-mail: millan@oo.upc.edu

    2008-11-01

    A multiplexed programmable diffractive lens, displayed on a pixelated liquid crystal device under broadband illumination, is proposed to compensate for the severe chromatic aberration that affects diffractive elements. The proposed lens is based on multiplexing a set of sublenses with a common focal length for different wavelengths. We consider different types of integration of the optical information (spatial only, temporal only and hybrid spatial-temporal) combined with a proper selection of the spectral bandwidth. The properties and limits of the achromatic programmable multiplexed lens are described. Experimental results are presented and discussed.

  15. Multiplexing schemes for an achromatic programmable diffractive lens

    A multiplexed programmable diffractive lens, displayed on a pixelated liquid crystal device under broadband illumination, is proposed to compensate for the severe chromatic aberration that affects diffractive elements. The proposed lens is based on multiplexing a set of sublenses with a common focal length for different wavelengths. We consider different types of integration of the optical information (spatial only, temporal only and hybrid spatial-temporal) combined with a proper selection of the spectral bandwidth. The properties and limits of the achromatic programmable multiplexed lens are described. Experimental results are presented and discussed.

  16. Use achromatic beam line for Hall C beam energy measurement

    There are several different methods to measure accelerator beam energy, for example, from frequency spectrum measurement and calculation of orbit length from accurate measurement of magnetic field in a reference dipole magnet from high precision floating wire analogue, and from detecting the synchrotron radiation emitted from kicker magnets. In this report an achromatic spectrometer method combined with calibrating a reference magnet and determining the deflection angle of spectrometer is proposed. The similar method will be used to measure beam energy in Bates Linear Accelerator Center, a 10-3 accuracy of beam energy measurement is expected

  17. Metrology of achromatic diffractive features on chalcogenide lenses

    Scordato, M.; Nelson, J.; Schwertz, K.; Mckenna, P.; Bagwell, J.

    2015-10-01

    Achromatic diffractive features on lenses are widely used in industry for color correction, however there is not a welldefined standard to quantify the performance of the lenses. One metric used to qualify a lens is the sag deviation from the nominal lens profile. Imperfections in the manufacturing of the diffractive feature may cause scattering and performance loss. This is not reflected in sag deviation measurements, therefore performance measurements are required. There are different quantitative approaches to measuring the performance of an achromatic diffractive lens. Diffraction efficiency, a measure of optical power throughput, is a common design metric used to define the percent drop from the modulation transfer function (MTF) metric. The line spread function (LSF) shows a layout of the intensity with linear distance and an ensquared energy specification can be implemented. The MTF is a common analysis tool for assemblies and can be applied to a single element. These functional tests will be performed and compared with diffractive lenses manufactured by different tool designs. This paper displays the results found with various instruments. Contact profilometry was used to inspect the profile of the diffractive elements, and a MTF bench was used to characterize lens performance. Included will be a discussion comparing the results of profile traces and beam profiles to expected diffraction efficiency values and the effects of manufacturing imperfections.

  18. Size, weight, and power reduction regimes in achromatic gradient-index singlets.

    Campbell, Sawyer D; Brocker, Donovan E; Nagar, Jogender; Werner, Douglas H

    2016-05-01

    By analyzing the limitations that achromatic gradient-index (GRIN) lens solutions in the radial and axial extremes place on lens thickness and surface curvature, a radial-axial hybrid GRIN theory is developed in order to overcome these restrictions and expose a larger solution space. With the achromatic hybrid GRIN theory, the trade-offs between thickness, curvature, and GRIN type can be directly studied in the context of size, weight, and power (SWaP) reduction. Finally, the achromatic solution space of a silicon-germanium-based material system is explored, and several designs are verified with ray tracing. PMID:27140376

  19. A Second-Order Achromat Design Based on FODO Cell

    Sun, Yipeng; /SLAC

    2011-08-19

    Two dipole doglegs are widely used to translate the beam axis horizontally or vertically. Quadrupoles are placed between the two consecutive dipoles to match first order dispersion and provide betatron focusing. Similarly a four dipole chicane is usually employed to form a bypass region, where the beam axis is transversely shifted first, then translated back to the original axis. In order to generate an isochronous section, quadrupoles are again needed to tune the first order transfer matrix element R{sub 56} equaling zero. Usually sextupoles are needed to correct second order dispersion in the bending plane, for both the dogleg optics and the chicane (with quad) optics. In this paper, an alternative optics design is introduced, which is based on a simple FODO cell and does not need sextupoles assistance to form a second-order achromat. It may provide a similar function of either a dogleg or a bypass, by using 2 or 4 of such combined supercells.

  20. Symmetric Achromatic Low-Beta Collider Interaction Region Design Concept

    We present a new symmetry-based concept for an achromatic low-beta collider interaction region design. A specially-designed symmetric Chromaticity Compensation Block (CCB) induces an angle spread in the passing beam such that it cancels the chromatic kick of the final focusing quadrupoles. Two such CCB?s placed symmetrically around an interaction point allow simultaneous compensation of the 1st-order chromaticities and chromatic beam smear at the IP without inducing significant 2nd-order aberrations. We first develop an analytic description of this approach and explicitly formulate 2nd-order aberration compensation conditions at the interaction point. The concept is next applied to develop an interaction region design for the ion collider ring of an electron-ion collider. We numerically evaluate performance of the design in terms of momentum acceptance and dynamic aperture. The advantages of the new concept are illustrated by comparing it to the conventional distributed-sextupole chromaticity compensation scheme

  1. Symmetric achromatic low-beta collider interaction region design concept

    Morozov, V S; Lin, F; Johnson, R P

    2012-01-01

    We present a new symmetry-based concept for an achromatic low-beta collider interaction region design. A specially-designed symmetric Chromaticity Compensation Block (CCB) induces an angle spread in the passing beam such that it cancels the chromatic kick of the final focusing quadrupoles. Two such CCBs placed symmetrically around an interaction point allow simultaneous compensation of the 1st-order chromaticities and chromatic beam smear at the IP without inducing significant 2nd-order aberrations to the particle trajectory. We first develop an analytic description of this approach and explicitly formulate 2nd-order aberration compensation conditions at the interaction point. The concept is next applied to develop an interaction region design for the ion collider ring of an electron-ion collider. We numerically evaluate performance of the design in terms of momentum acceptance and dynamic aperture. The advantages of the new concept are illustrated by comparing it to the conventional distributed-sextupole chr...

  2. Quasi-achromatic Fresnel zone lens with ring focus.

    Vijayakumar, A; Bhattacharya, Shanti

    2014-03-20

    The phase of a standard Fresnel zone lens (FZL) is periodically modulated in the radial direction using the phase of a binary fraxicon. The resulting element (rf-FZL) focuses light into a ring. The ring is found to be quasi-achromatic, in that the diameter is wavelength independent but its location is not. The binary rf-FZL is fabricated using electron beam direct writing. Experimental results confirm the generation of a wavelength-independent ring pattern at the focus of the rf-FZL. An efficiency of 24% was obtained. The variation in radius of ring pattern was reduced from 61 μm to less than 10 nm for a corresponding wavelength variation from 532 to 633 nm. PMID:24663478

  3. Psychophysical Evaluation of Achromatic and Chromatic Vision of Workers Chronically Exposed to Organic Solvents

    Luiz Carlos de Lima Silveira; Dora Fix Ventura; Lauro José Barata de Lima; Cláudio Eduardo Correa Teixeira; Anderson Raiol Rodrigues; Eliza Maria da Costa Brito Lacerda; Monica Gomes Lima

    2012-01-01

    The purpose of this paper was to evaluate achromatic and chromatic vision of workers chronically exposed to organic solvents through psychophysical methods. Thirty-one gas station workers (31.5 ± 8.4 years old) were evaluated. Psychophysical tests were achromatic tests (Snellen chart, spatial and temporal contrast sensitivity, and visual perimetry) and chromatic tests (Ishihara's test, color discrimination ellipses, and Farnsworth-Munsell 100 hue test—FM100). Spatial contrast sensitivities of...

  4. CIAXE: co-axial achromatic interferential coronagraph: first laboratory results

    Allouche, Fatmé; Gay, Jean; Rabbia, Yves; Assus, Pierre

    2010-07-01

    In 1996, Jean Gay and Yves Rabbia presented their Achromatic Interferential Coronagraph (AIC) for detecting and imaging faint companions (ultimately exoplanets) in the neighboring of a star. As presented then, the Michleson-like Interferometer configuration of the AIC hardens its insertion into an existing (coaxial) optical train, the output beam of the AIC being delivered at right angle from the input beam. To overcome this, they reconfigured the AIC into a compact and fully axial coronagraph, the CIAXE, which main feature consists of using two thick lenses machined in the same optical material. For the CIAXE to deliver the output beam along the same axis as the input beam, the two lenses are coaxially disposed on the optical axis and are separated, at their common spherical contact surface by a thin air gap acting like a beam splitter. We have set up a laboratory experiment aiming at validating the principle of the concept. Our first step was to equalize the thicknesses of the two lenses, so as to make zero the optical path difference between both arms. For this, the (residual) value of the OPD has been evaluated and then the lenses have been re-machined so as to decrease as far as technologically possible, the thicknesses mismatch. As a second step, a micro-controlled rotation around the common curvature center of the spherical surfaces of the lenses is applied. This allows a fine tuning of the residual OPD at the required accuracy level. Are presented here test bench, steps and results.

  5. Edge detection depends on achromatic channel in Drosophila melanogaster.

    Zhou, Yanqiong; Ji, Xiaoxiao; Gong, Haiyun; Gong, Zhefeng; Liu, Li

    2012-10-01

    Edges represent important information in object recognition, and thus edge detection is crucial for animal survival. Various types of edges result from visual contrast, such as luminance contrast and color contrast. So far, the molecular and neural mechanisms underlying edge detection and the relationship between different edge information-processing pathways have been largely undemonstrated. In the present study, using a color light-emitting-diode-based Buridan's paradigm, we demonstrated that a blue/green demarcation is able to generate edge-orientation behavior in the adult fly. There is a blue/green intensity ratio, the so-called point of equal luminance, at which wild-type flies did not show obvious orientation behavior towards edges. This suggests that orientation behavior towards edges is dependent on luminance contrast in Drosophila. The results of mutants ninaE(17) and sev(LY3);rh5(2);rh6(1) demonstrated that achromatic R1-R6 photoreceptor cells, but not chromatic R7/R8 photoreceptor cells, were necessary for orientation behavior towards edges. Moreover, ectopic expression of rhodopsin 4 (Rh4), Rh5 or Rh6 could efficiently restore the edge-orientation defect in the ninaE(17) mutant. Altogether, our results show that R1-R6 photoreceptor cells are both necessary and sufficient for orientation behavior towards edges in Drosophila. PMID:22735352

  6. Achromatic Focal Plane Mask for Exoplanet Imaging Coronagraphy

    Newman, Kevin Edward; Belikov, Ruslan; Guyon, Olivier; Balasubramanian, Kunjithapatham; Wilson, Dan

    2013-01-01

    Recent advances in coronagraph technologies for exoplanet imaging have achieved contrasts close to 1e10 at 4 lambda/D and 1e-9 at 2 lambda/D in monochromatic light. A remaining technological challenge is to achieve high contrast in broadband light; a challenge that is largely limited by chromaticity of the focal plane mask. The size of a star image scales linearly with wavelength. Focal plane masks are typically the same size at all wavelengths, and must be sized for the longest wavelength in the observational band to avoid starlight leakage. However, this oversized mask blocks useful discovery space from the shorter wavelengths. We present here the design, development, and testing of an achromatic focal plane mask based on the concept of optical filtering by a diffractive optical element (DOE). The mask consists of an array of DOE cells, the combination of which functions as a wavelength filter with any desired amplitude and phase transmission. The effective size of the mask scales nearly linearly with wavelength, and allows significant improvement in the inner working angle of the coronagraph at shorter wavelengths. The design is applicable to almost any coronagraph configuration, and enables operation in a wider band of wavelengths than would otherwise be possible. We include initial results from a laboratory demonstration of the mask with the Phase Induced Amplitude Apodization coronagraph.

  7. Broadband Achromatic Phase Shifter for a Nulling Interferometer

    Bolcar, Matthew R.; Lyon, Richard G.

    2011-01-01

    Nulling interferometry is a technique for imaging exoplanets in which light from the parent star is suppressed using destructive interference. Light from the star is divided into two beams and a phase shift of radians is introduced into one of the beams. When the beams are recombined, they destructively interfere to produce a deep null. For monochromatic light, this is implemented by introducing an optical path difference (OPD) between the two beams equal to lambda/2, where lambda is the wavelength of the light. For broadband light, however, a different phase shift will be introduced at each wavelength and the two beams will not effectively null when recombined. Various techniques have been devised to introduce an achromatic phase shift a phase shift that is uniform across a particular bandwidth. One popular technique is to use a series of dispersive elements to introduce a wavelength-dependent optical path in one or both of the arms of the interferometer. By intelligently choosing the number, material and thickness of a series of glass plates, a nearly uniform, arbitrary phase shift can be introduced between two arms of an interferometer. There are several constraints that make choosing the number, type, and thickness of materials a difficult problem, such as the size of the bandwidth to be nulled. Several solutions have been found for bandwidths on the order of 20 to 30 percent (Delta(lambda)/lambda(sub c)) in the mid-infrared region. However, uniform phase shifts over a larger bandwidth in the visible regime between 480 to 960 nm (67 percent) remain difficult to obtain at the tolerances necessary for exoplanet detection. A configuration of 10 dispersive glass plates was developed to be used as an achromatic phase shifter in nulling interferometry. Five glass plates were placed in each arm of the interferometer and an additional vacuum distance was also included in the second arm of the interferometer. This configuration creates a phase shift of pi radians with

  8. Achromatic and isochronous lattice design of P2DT bending section in RAON accelerator

    Jin, Hyunchang, E-mail: hcjin@ibs.re.kr; Jang, Ji-Ho; Jang, Hyojae; Hong, In-Seok; Jeon, Dong-O

    2015-09-21

    In RAON heavy ion accelerator, generally, the In-flight Fragmentation (IF) and Isotope Separation On-Line (ISOL) systems are employed in order to produce various isotope beams. Out of the isotope beams, the beams generated by the ISOL system are transported from the low energy linac SCL3 to the high energy driver linac SCL2. The post-accelerator to the driver linac transport (P2DT) section that consists of the charge stripper section, the 180° bending section, and the SCL2 matching section is placed between the SCL3 and the SCL2. In this P2DT section, however, the transverse and longitudinal emittance growth can aggravate the beam acceptance of the SCL2. Besides, the growth at the P2DT 180° bending section is considered a significant issue because of the unexpected achromatic effect. Therefore an achromatic and isochronous lattice design should be devised to prevent the transverse and longitudinal emittance from increasing while the multi-charge beams flow through the bending section. This study reports an improved design for the achromatic and isochronous lattice up to the second-order. After satisfying the first-order achromatic and isochronous condition by adjusting the field strength of quadrupoles with this design, the simple and efficient method will be utilized with the aim of getting the minimum number of sextupoles. The research on the collimator for the charge selection at the bending section will be also represented by using the designed lattice.

  9. Achromatic and isochronous lattice design of P2DT bending section in RAON accelerator

    In RAON heavy ion accelerator, generally, the In-flight Fragmentation (IF) and Isotope Separation On-Line (ISOL) systems are employed in order to produce various isotope beams. Out of the isotope beams, the beams generated by the ISOL system are transported from the low energy linac SCL3 to the high energy driver linac SCL2. The post-accelerator to the driver linac transport (P2DT) section that consists of the charge stripper section, the 180° bending section, and the SCL2 matching section is placed between the SCL3 and the SCL2. In this P2DT section, however, the transverse and longitudinal emittance growth can aggravate the beam acceptance of the SCL2. Besides, the growth at the P2DT 180° bending section is considered a significant issue because of the unexpected achromatic effect. Therefore an achromatic and isochronous lattice design should be devised to prevent the transverse and longitudinal emittance from increasing while the multi-charge beams flow through the bending section. This study reports an improved design for the achromatic and isochronous lattice up to the second-order. After satisfying the first-order achromatic and isochronous condition by adjusting the field strength of quadrupoles with this design, the simple and efficient method will be utilized with the aim of getting the minimum number of sextupoles. The research on the collimator for the charge selection at the bending section will be also represented by using the designed lattice

  10. New Light on an Old Question: Who Invented the Achromatic Telescope?

    Rudd, M. Eugene; Jaecks, Duane H.; Willach, Rolf; Sorrenson, Richard; Abrahams, Peter

    A discussion of the events leading up to the invention of the achromatic telescope, including topics on spherical aberration and Franciscus Maurolycus, the discovery of chromatic aberration, Issac Newton, John Dollond and his experiments, Samuel Klingenstierna, patent trials, and letters from Dollond and Ramsden.

  11. Wide-angle and high-efficiency achromatic metasurfaces for visible light

    Deng, Zi-Lan; Wang, Guo Ping

    2016-01-01

    Recently, an achromatic metasurface was successfully demonstrated to deflect light of multiple wavelengths in the same direction and it was further applied to the design of planar lenses without chromatic aberrations [Science, 347, 1342(2015)]. However, such metasurface can only work for normal incidence and exhibit low conversion efficiency. Here, we present an ultrawide-angle and high-efficiency metasurface without chromatic aberration for wavefront shaping in visible range. The metasurface is constructed by multiple metallic nano-groove gratings, which support enhanced diffractions for an ultrawide incident angle range from 10o to 80o due to the excitations of localized gap plasmon modes at different resonance wavelengths. Incident light at these resonance wavelengths can be efficiently diffracted into the same direction with complete suppression of the specular reflection. This approach is applied to the design of an achromatic flat lens for focusing light of different wavelengths into the same position. ...

  12. Measurements of emittance growth through the achromatic bend at the BNL Accelerator Test Facility

    Measurements of emittance growth in a high peak current beam as it passes through an achromatic double bend are summarized. Experiments were performed using the ATF at Brookhaven National Laboratory by X.J. Wang and D. Kehne as a collaboration resulting from the proposal attached at the end of the document. The ATF consists off an RF gun (1 MeV), two sections of linac (40-75 MeV), a diagnostic section immediately following the linac, a 20 degree bend magnet, a variable aperture slit at a high dispersion point, 5 quadrupoles, then another 20 degree bend followed by another diagnostic section. The TRANSPORT deck describing the region from the end of the linac to the end of the diagnostic line following the achromatic bends is attached to the end of this document. Printouts of the control screens are also attached

  13. Psychophysical Evaluation of Achromatic and Chromatic Vision of Workers Chronically Exposed to Organic Solvents

    The purpose of this paper was to evaluate achromatic and chromatic vision of workers chronically exposed to organic solvents through psychophysical methods. Thirty-one gas station workers (31.5 ± 8.4 years old) were evaluated. Psychophysical tests were achromatic tests (Snellen chart, spatial and temporal contrast sensitivity, and visual perimetry) and chromatic tests (Ishihara's test, color discrimination ellipses, and Farnsworth-Munsell 100 hue test FM100). Spatial contrast sensitivities of exposed workers were lower than the control at spatial frequencies of 20 and 30 cpd whilst the temporal contrast sensitivity was preserved. Visual field losses were found in 10-30 degrees of eccentricity in the solvent exposed workers. The exposed workers group had higher error values of FM100 and wider color discrimination ellipses area compared to the controls. Workers occupationally exposed to organic solvents had abnormal visual functions, mainly color vision losses and visual field constriction

  14. Feasibility analysis of an achromatic quarter wave plate in a static polarizing wind imaging interferometer

    A modified static polarizing wind imaging interferometer (SPWII) for measuring the upper atmospheric wind and temperature is presented. The atmospheric temperature and wind velocity can be derived by observing multiple emission lines. The principle of the SPWII is described. The effects of the dispersion of the quarter wave plates on the derived results are analyzed. Using a simulated annealing algorithm, some multilayer achromatic quarter wave plates (AQWPs) are designed to suppress the errors introduced by the dispersion. Two alternative AQWPs (six- and ten-layer) are obtained. The transmission loss of the interferometer and the measurement errors of atmospheric temperature and wind velocity introduced through dispersion can, through the use of achromatic QWPs, be reduced to below 0.2%, 0.15 K and 0.03 m s−1, respectively. (paper)

  15. Tests of achromatic phase shifters performed on the SYNAPSE test bench: a progress report

    Gabor, Pavel; Schuller, Peter A.; Chazelas, Bruno; Decaudin, Michel; Labèque, Alain; Duret, Philippe; Rabbia, Yves; Launhardt, Ralf; Gay, Jean; Sodnik, Zoran; Barillot, Marc; Brachet, Frank; Laurent, Thomas; Jacquinod, Sophie; Vandormael, Denis

    2008-01-01

    The achromatic phase shifter (APS) is a component of the Bracewell nulling interferometer studied in preparation for future space missions (viz. Darwin/TPF-I) focusing on spectroscopic study of Earth-like exo-planets. Several possible designs of such an optical subsystem exist. Four approaches were selected for further study. Thales Alenia Space developed a dielectric prism APS. A focus crossing APS prototype was developed by the OCA, Nice, France. A field reversal APS prototype was prepared ...

  16. Demonstration of Achromatic Cold-Neutron Microscope Utilizing Axisymmetric Focusing Mirrors

    Liu, D.; Hussey, D; Gubarev, M. V.; Ramsey, B. D.; Jacobson, D.; Arif, M.; Moncton, D.E.; Khaykovich, B.

    2013-01-01

    An achromatic cold-neutron microscope with magnification 4 is demonstrated. The image-forming optics is composed of nested coaxial mirrors of full figures of revolution, so-called Wolter optics. The spatial resolution, field of view, and depth of focus are measured and found consistent with ray-tracing simulations. Methods of increasing the resolution and magnification are discussed, as well as the scientific case for the neutron microscope. In contrast to traditional pinhole-camera neutron i...

  17. Uncoupled achromatic condition of a dog-leg system with the presence of RF cavities

    Geng, Huiping

    2013-01-01

    To merge the beam from either of the two injectors to the main linac, a dog-leg system will be employed in the second Medium Energy Beam Transport (MEBT2) line of the China ADS driving accelerator. The achromatic condition has to be guaranteed to avoid beam center excursion against energy jitter. RF cavities were found indispensable to control the bunch length growth in the dog-leg system of MEBT2. The full uncoupling between transverse and longitudinal plane is desired to minimize the growth of projected rms emittances. The uncoupled achromatic condition of this dogleg system with the presence of RF bunching cavities will be deduced using the method of transfer matrixes. It is found that to fulfil the uncoupling condition, the distance between the bunching cavities is uniquely determined by the maximum energy gain of the RF cavities. The theoretical analysis is verified by the simulation code TraceWin. The space charge effect on the uncoupled achromatic condition and the beam emittance growth will also be di...

  18. Chromatic-achromatic perimetry in four clinic cases: Glaucoma and diabetes

    Inmaculada Cabezos

    2015-01-01

    Full Text Available Background: Some diseases that affect the visual system may show loss of chromatic-achromatic sensitivity before obvious physical signs appear in the usual examination of the eye′s posterior segment. A perimetric study has been conducted with four typical patients with glaucoma and diabetes, at different stages of the disease. Materials and Methods: In addition to the standard white-on-white (standard automated perimetry [SAP], a test battery has been used to study patient′s contrast sensitivity, using stimuli with different chromatic, spatial, and temporal content (multichannel perimetry. The choice of stimuli tries to maximize the response of different visual mechanisms: Achromatic (parvocellular and magnocellular origin; chromatic red-green (parvocellular origin; and chromatic blue-yellow (koniocellular origin. Results: The results seem to indicate losses in the achromatic-parvocellular perimetry and both chromatic perimetry tests, undetected by conventional SAP. Conclusions: Our results illustrate that our patients without visible retinal alterations show signs of suspicion in multichannel perimetry.

  19. Super-achromatic microprobe for ultrahigh-resolution endoscopic OCT imaging at 800 nm (Conference Presentation)

    Yuan, Wu; Alemohammad, Milad; Yu, Xiaoyun; Yu, Shaoyong; Li, Xingde

    2016-03-01

    In this paper, we report a super-achromatic microprobe made with fiber-optic ball lens to enable ultrahigh-resolution endoscopic OCT imaging. An axial resolution of ~2.4 µm (in air) can be achieved with a 7-fs Ti:Sapphire laser. The microprobe has minimal astigmatism which affords a high transverse resolution of ~5.6 µm. The miniaturized microprobe has an outer diameter of ~520 µm including the encasing metal guard and can be used to image small luminal organs. The performance of the ultrahigh-resolution OCT microprobe was demonstrated by imaging rat esophagus, guinea pig esophagus, and mouse rectum in vivo.

  20. The Achromatic Telescopic Squeezing Scheme: Basic Principles and First Demonstration at the LHC

    Fartoukh, S; Hofle, W; Lamont, M; de Maria, R; Miyamoto, R; Muller, G; Ponce, L; Redaelli, S; Steinhagen, R; Strzelczyk, M; Tomas, R; Vanbavinckhove, G; Wenninger, J

    2012-01-01

    The Achromatic Telescopic Squeezing (ATS) scheme is a novel squeezing mechanism enabling the production of very low β* in circular colliders. The basic principles of the ATS scheme will be reviewed together with its strong justification for the High-Luminosity LHC Project. In this context, a few dedicated experiments with beam were meticulously prepared and took place at the LHC in 2011. The results obtained will be highlighted, demonstrating the potential of the ATS scheme for any upgrade project relying on a strong reduction of β*.

  1. Opto-thermo-mechanical numerical simulations of 3 different concepts of infrared achromatic phase shifters

    Chazelas, Bruno; Valette, Claude; Lépine, Thierry; Barillot, Marc; Brachet, Frank; Dervaux, Sebastien; Fressin, François; Gay, Jean; Gadret, Gregory; Labèque, Alain; Launhardt, Ralph; Mangin, Jacques; Mawet, Dimitri; Ollivier, Marc; Rabbia, Yves

    2004-01-01

    The Darwin/TPF mission aims at detecting directly extra solar planets. It is based on the nulling interferometry, concept proposed by Bracewell in 1978, and developed since 1995 in several European and American laboratories. One of the key optical devices for this technique is the achromatic phase shifter (APS). This optical component is designed to produce a π phase shift over the whole Darwin spectral range (i.e. 6-18 μm), and will be experimentally tested on the NULLTIMATE consortium nulli...

  2. Modular Organization of Mechanisms of Achromatic Vision in Human and Animals

    Aleksander M. Chernorizov

    2011-01-01

    Full Text Available Psychophysiological research into achromatic vision in humans and vertebrates displays that light intensity is coded by a two-dimensional "excitation vector". The components of that vector are responses of brightness and darkness neurons (or, according to another classification, on- and o/f-neurons. It means that a current sensation of brightness is determined by a corresponding interrelation between activities of those two systems responding in opponent way to set. The present research is devoted to testing of a hypothesis asserting that two-module organization of achromatic vision is a universal principle of brightness coding in a wide raw of animals including invertebrates. The paper represents certain results of registration and analysis of electroretinogram and total activity of the optical nerve in snail Helix lucorum to diffuse light flashes of different intensities. The obtained experimental data, along with the already existing reference data, allow us to assume that on- and off-systems may constitute the neural basis for brightness coding in the invertebrates. The peculiarity of on- and o/f-systems in vertebrates is that they are formed already at the photoreceptor level.

  3. Ion beam transport and focus for LMF using an achromatic solenoidal lens system

    The light ion LMF (Laboratory Microfusion Facility) requires an ion beam transport length for bunching and standoff to be about four meters from the diode to the target. The baseline LMF transport scheme uses an achromatic two lens system consisting of the diode (a self-field lens) and a solenoidal lens. Charge and current neutralization are provided by a background gas. A detailed analysis of this system is presented here. The effects of additional magnetic fields are examined, including those produced by non-zero net currents, applied B effects near the diode, and diamagnetic effects in the solenoidal lens. Instabilities are analyzed including the filamentation instability, the two-stream instability (beam ions, plasma electrons), the plasma two-stream instability (plasma electrons, plasma ions), and the ion acoustic instability. Scattering in the foil and gas are shown to be negligible. Gas breakdown processes are analyzed in detail, including ion impact ionization, electron avalanching, and ohmic heating. Special diode requirements are examined, including voltage accuracy, energy spread, and aiming tolerances. The neutral gas and gas pressure are chosen to satisfy several constraints, one being that the net current must be small, and another being that the filamentation instability should be avoided. With the present choice of 1 Torr He, it is concluded that the complete achromatic lens system appears to be viable, simple, and efficient transport and focusing system for LMF

  4. The nature of the late achromatic bump in GRB 120326A

    Melandri, A; Guidorzi, C; Bernardini, M G; Kobayashi, S; Mundell, C G; Gomboc, A; Dintinjana, B; Hentunen, V -P; Japelj, J; Kopač, D; Kuroda, D; Morgan, A N; Steele, I A; Quadri, U; Arici, G; Arnold, D; Girelli, R; Hanayama, H; Kawai, N; Mikuž, H; Nissinen, M; Salmi, T; Smith, R J; Strabla, L; Tonincelli, M; Quadri, A

    2014-01-01

    The long ${\\it Swift}$ gamma-ray burst GRB 120326A at redshift $z=1.798$ exhibited a multi-band light curve with a striking feature: a late-time, long-lasting achromatic rebrightening, rarely seen in such events. Peaking in optical and X-ray bands $\\sim 35$ ks ($\\sim 12.5$ ks in the GRB rest frame) after the 70-s GRB prompt burst, the feature brightens nearly two orders of magnitude above the underlying optical power-law decay. Modelling the multiwavelength light curves, we investigate possible causes of the rebrightening in the context of the standard fireball model. We exclude a range of scenarios for the origin of this feature: reverse-shock flash, late-time forward shock peak due to the passage of the maximal synchrotron frequency through the optical band, late central engine optical/X-ray flares, interaction between the expanding blast wave and a density enhancement in the circumburst medium and gravitational microlensing. Instead we conclude that the achromatic rebrightening may be caused by a refreshed...

  5. Predispersor-achromat as an imput chamber for an electron energy analyzer

    To improve characteristics of the Yuz-Rozhanskij electron energy analyzer, it is suggested to equip it with a preliminary monochromatization chamber which presents a spherical Lukirskij capacitor with three grids. The chamber permits to focus on the analyzer slit, from the whole flux, only a portion of the electrons with the energies within e#betta# Vsub(r) - of a slight excess over the value corresponding to the retarding potential, Vsub(r). In that case, during the spectrum scanning by means of the Vsub(r) potential, the conditions of focusing on the analyzer slit prove to be independent of the electron intrinsic energy, and the apparatus function - to be achromatic. The spectra recorded following the new technique are presented with the 0.2 eV resolution. The spectra are quite free from background resulting from the electron scattering in the analyzer

  6. Achromatic approach to phase-based multi-modal imaging with conventional X-ray sources.

    Endrizzi, Marco; Vittoria, Fabio A; Kallon, Gibril; Basta, Dario; Diemoz, Paul C; Vincenzi, Alessandro; Delogu, Pasquale; Bellazzini, Ronaldo; Olivo, Alessandro

    2015-06-15

    Compatibility with polychromatic radiation is an important requirement for an imaging system using conventional rotating anode X-ray sources. With a commercially available energy-resolving single-photon-counting detector we investigated how broadband radiation affects the performance of a multi-modal edge-illumination phase-contrast imaging system. The effect of X-ray energy on phase retrieval is presented, and the achromaticity of the method is experimentally demonstrated. Comparison with simulated measurements integrating over the energy spectrum shows that there is no significant loss of image quality due to the use of polychromatic radiation. This means that, to a good approximation, the imaging system exploits radiation in the same way at all energies typically used in hard-X-ray imaging. PMID:26193618

  7. Achromatic Low-Beta Interaction Region Design For An Electron-Ion Collider

    An achromatic Interaction Region (IR) design concept is presented with an emphasis on its application at an electron-ion collider. A specially-designed symmetric Chromaticity Compensation Block (CCB) induces an angle spread in the passing beam such that it cancels the chromatic kick of the final focusing quadrupoles. Two such CCB's placed symmetrically around an interaction point (IP) allow simultaneous compensation of the 1st-order chromaticities and chromatic beam smear at the IP without inducing significant 2nd-order aberrations. Special attention is paid to the difference in the electron and ion IR design requirements. We discuss geometric matching of the electron and ion IR footprints. We investigate limitations on the momentum acceptance in this IR design.

  8. Achromatic flat optical components via compensation between structure and material dispersions

    Li, Yang; Li, Xiong; Pu, Mingbo; Zhao, Zeyu; Ma, Xiaoliang; Wang, Yanqin; Luo, Xiangang

    2016-01-01

    Chromatism causes great quality degradation of the imaging system, especially for diffraction imaging. The most commonly method to overcome chromatism is refractive/diffractive hybrid optical system which, however, sacrifices the light weight and integration property of diffraction elements. A method through compensation between the structure dispersion and material dispersion is proposed to overcome the chromatism in flat integrated optical components. This method is demonstrated by making use of silver nano-slits waveguides to supply structure dispersion of surface plasmon polaritons (SPP) in metal-insulator-metal (MIM) waveguide to compensate the material dispersion of metal. A broadband deflector and lens are designed to prove the achromatic property of this method. The method demonstrated here may serve as a solution of broadband light manipulation in flat integrated optical systems.

  9. Suppression of the emittance growth induced by coherent synchrotron radiation in triple-bend achromat

    Huang, Xiyang; Cui, Xiaohao; Xu, Gang

    2014-01-01

    Coherent synchrotron radiation (CSR) effect at a bending path plays an important role in transverse emittance dilution in high-brightness light sources and linear colliders, where the electron beams are of short bunch length and of high peak current. Suppression of the emittance growth induced by CSR is essential and critical to preserve the beam quality and to help improve the machine performance. To evaluate the CSR effect analytically, we have proposed a novel method, which enabled us to obtain generic conditions of cancelling the CSR linear effect in a two-dipole achromat. In this paper, it illustrates that with this method the CSR-cancellation condition can be obtained for a TBA with symmetric layout, which is independent of concrete element parameters, and to a large extent, the initial beam distribution. Implementation of found condition in concrete optics design of a TBA is discussed, and the proposed condition is verified through numerical simulations.

  10. Achromatic polarization manipulation by dispersion management of anisotropic meta-mirror with dual-metasurface.

    Guo, Yinghui; Yan, Lianshan; Pan, Wei; Luo, Bin

    2015-10-19

    A dual-metasurface-based reflective device ("meta-mirror") has been proposed for broadband polarization manipulation, which is composed of orthogonal metallic cut-wire arrays separated from a grounded plane with different distances. The reflective phases of orthogonally linearly-polarized components can be independently adjusted by changing the dimensions of the cut-wire pairs. Benefiting from the fully released dispersion management ability in both dimensions, achromatic (i.e., ultra-broadband) polarization manipulation can be achieved. The suggested approach has been numerically verified in both microwave and optical band. Moreover, experimental characterization in microwave regime has demonstrated the broadband polarization manipulation ability within 5 - 30 GHz. The underlying physical mechanism of dispersion engineering was explained in general equivalent circuit theory and transmission line model. PMID:26480416

  11. Design study for achromatic and isochronous 1800 bending systems for PIGMI

    A Pion Generator for Medical Irradiation (PIGMI) possessing many technical innovations is being developed at the Los Alamos Scientific Laboratory. The heart of the PIGMI facility is a linear accelerator designed to provide a 650-MeV beam of protons at a beam current of 100 μA. The accelerator will be 120 m long and suitable for installation at major hospital sites. Obviously, a shorter machine may be more convenient to the medical profession. One possibility of reducing the total length of the facility is to bend the linac back on itself at the halfway point. However, the 1800 bending system used for this purpose must have the very special properties of being both achromatic and isochronous in order to transport the proton beam without destroying the transverse or longitudinal dimensions of the bunch. The design of two such possible systems is dicussed

  12. Visible–infrared achromatic imaging by wavefront coding with wide-angle automobile camera

    Ohta, Mitsuhiko; Sakita, Koichi; Shimano, Takeshi; Sugiyama, Takashi; Shibasaki, Susumu

    2016-09-01

    We perform an experiment of achromatic imaging with wavefront coding (WFC) using a wide-angle automobile lens. Our original annular phase mask for WFC was inserted to the lens, for which the difference between the focal positions at 400 nm and at 950 nm is 0.10 mm. We acquired images of objects using a WFC camera with this lens under the conditions of visible and infrared light. As a result, the effect of the removal of the chromatic aberration of the WFC system was successfully determined. Moreover, we fabricated a demonstration set assuming the use of a night vision camera in an automobile and showed the effect of the WFC system.

  13. Tests of achromatic phase shifters performed on the SYNAPSE test bench: a progress report

    Gabor, Pavel; Chazelas, Bruno; Decaudin, Michel; Labèque, Alain; Duret, Philippe; Rabbia, Yves; Launhardt, Ralf; Gay, Jean; Sodnik, Zoran; Barillot, Marc; Brachet, Frank; Laurent, Thomas; Jacquinod, Sophie; Vandormael, Denis; Loicq, Jérôme; Mawet, Dimitri; Ollivier, Marc; Léger, Alain; 10.1117/12.789269

    2008-01-01

    The achromatic phase shifter (APS) is a component of the Bracewell nulling interferometer studied in preparation for future space missions (viz. Darwin/TPF-I) focusing on spectroscopic study of Earth-like exo-planets. Several possible designs of such an optical subsystem exist. Four approaches were selected for further study. Thales Alenia Space developed a dielectric prism APS. A focus crossing APS prototype was developed by the OCA, Nice, France. A field reversal APS prototype was prepared by the MPIA in Heidelberg, Germany. Centre Spatial de Li\\`ege develops a concept based on Fresnel's rhombs. This paper presents a progress report on the current work aiming at evaluating these prototypes on the SYNAPSE test bench at the Institut d'Astrophysique Spatiale in Orsay, France.

  14. Achromatization of conical diffraction: application to the generation of a polychromatic optical vortex.

    Fallet, Clement; Sirat, Gabriel Y

    2016-02-15

    Vortex beams are plagued by the intrinsic chromaticity of the physical phenomenon used to generate them. To the authors' best knowledge, attempts to generate them in a broad spectral range remain quite scarce and limited in their results. Crystal optics and especially conical diffraction (CD) (or refraction) intrinsically create achromatic vortices. The vortex is created by a wavelength-independent topological charge, embedded directly in the Fresnel equations. However, for biaxial crystals of low crystallographic symmetry, which includes all crystals used practically for CD, the dispersion of the binormal axis creates a chromaticity effect. In this Letter, we propose a new way to compensate this dispersion of the binormal axis of a biaxial crystal in order to generate white-light vortex beams by CD in a 250 nm spectral range, covering almost all the visible range. The advantages of the ability to use CD in a wide spectral range vastly exceed the sole generation of vortex beams. PMID:26872184

  15. Design of a triple-bend isochronous achromat with minimum coherent-synchrotron-radiation-induced emittance growth

    Venturini, M.

    2016-06-01

    Using a 1D steady-state free-space coherent synchrotron radiation (CSR) model, we identify a special design setting for a triple-bend isochronous achromat that yields vanishing emittance growth from CSR. When a more refined CSR model with transient effects is included in the analysis, numerical simulations show that the main effect of the transients is to shift the emittance growth minimum slightly, with the minimum changing only modestly.

  16. Design and imaging performance of achromatic diffractive/refractive X-ray and Gamma-ray Fresnel lenses

    Skinner, Gerald K.

    2004-01-01

    Achromatic combinations of a diffractive Phase Fresnel Lens and a refractive correcting element have been proposed for X-ray and gamma-ray astronomy and for microlithography, but considerations of absorption often dictate that the refractive component be given a stepped profile, resulting in a double Fresnel lens. The imaging performance of corrected Fresnel lenses, with and without `stepping' is investigated and the trade-off between resolution and useful bandwidth in different circumstances...

  17. Patterned dual-layer achromatic micro-quarter-wave-retarder array for active polarization imaging.

    Zhao, Xiaojin; Pan, Xiaofang; Fan, Xiaolei; Xu, Ping; Bermak, Amine; Chigrinov, Vladimir G

    2014-04-01

    In this paper, we present a liquid-crystal-polymer (LCP)-based dual-layer micro-quarter-wave-retarder (MQWR) array for active polarization image sensors. The proposed MQWRs, for the first time, enable the extraction of the incident light's circularly polarized components in the whole visible regime, which correspond to the fourth parameter of Stokes vector. Compared with the previous implementations, our proposed MQWRs feature high achromaticity, making their applications no longer limited to monochromatic illumination. In addition, the presented thin structure exhibits an overall thickness of 2.43μm, leading to greatly alleviated optical cross-talk between adjacent photo-sensing pixels. Moreover, the reported superior optical performance (e.g. minor transmittance, extinction ratio) validates our optical design and optimization of the proposed MQWRs. Furthermore, the demonstrated simple fabrication recipe offers a cost-effective solution for the monolithic integration between the proposed MQWR array and the commercial solid-state image sensors, which makes the multi-spectral full Stokes polarization imaging system on a single chip feasible. PMID:24718177

  18. Achromatic registration of quadrature components of the optical spectrum in spectral domain optical coherence tomography

    We have thoroughly investigated the method of simultaneous reception of spectral components with the achromatised quadrature phase shift between two portions of a reference wave, designed for the effective suppression of the 'mirror' artefact in the resulting image obtained by means of spectral domain optical coherence tomography (SD OCT). We have developed and experimentally tested a phase-shifting element consisting of a beam divider, which splits the reference optical beam into the two beams, and of delay lines being individual for each beam, which create a mutual phase difference of π/2 in the double pass of the reference beam. The phase shift achromatism over a wide spectral range is achieved by using in the delay lines the individual elements with different dispersion characteristics. The ranges of admissible adjustment parameters of the achromatised delay line are estimated for exact and inexact conformity of the geometric characteristics of its components to those calculated. A possibility of simultaneous recording of the close-to-quadrature spectral components with a single linear photodetector element is experimentally confirmed. The suppression of the artefact mirror peak in the OCT-signal by an additional 9 dB relative to the level of its suppression is experimentally achieved when the air delay line is used. Two-dimensional images of the surface positioned at an angle to the axis of the probe beam are obtained with the correction of the 'mirror' artefact while maintaining the dynamic range of the image. (laser biophotonics)

  19. A mid-infrared Mueller ellipsometer with pseudo-achromatic optical elements

    Garcia-Caurel, E; Ndong, G; Al-Bugami, B; Bernon, C; Al-Qahtani, E; Rengnez, F; De Martino, A

    2015-01-01

    The purpose of this article is to present a new broadband Mueller ellipsometer designed to work in the mid-infrared range, from 3 to 14 microns. The Mueller ellipsometer, which can be mounted in reflection or in transmission configuration, consists of a polarization state generator (PSG), a sample holder, and a polarization state analyzer (PSA). The PSG consists in one linear polarizer and a retarder sequentially rotated to generate a set of four optimal polarization states. The retarder consists in a bi-prism made of two identical Fresnel rhombs disposed symmetrically and joined by optical contact, giving the ensemble a "V" shape. Retardation is induced by the four total internal reflections that the beam undergoes when it propagates through the bi-prism. Total internal reflection allows to generate a quasi-achromatic retardation. The PSA is identical to the PSG, but with its optical elements mounted in reverse order. After a measurement run, the instrument yields a set of sixteen independent values, which i...

  20. Experiments for the isotope separation of secondary beams with the momentum-loss achromat

    In the past the use of an intermediate energy absorber in combination with the two-stage magnetic system LISE and GANIL has proven to be a very powerful method for the isotropic separation of projectile-like reaction products in the intermediate energy range. At relativistic energies, the use of thicker targets allows us to increase the production rates, and the ambiguities in the selection caused by the occurrence of not completely stripped ions are considerably reduced. Cross contaminants due to parasitic nuclear interactions of the secondary beam in the energy absorber which were foreseen as the main disadvantage in using relativistic beams proved to be unimportant. The very good separation of the method demonstrated in these experiments at SATURNE is to a large extent due to the fact that the momentum spread caused by the fragmentation process decreases in relative terms with increasing beam energy. This leads to a comparatively effective separation already in the first section of the separator. In these experiments the momentum-loss achromat was able to produce very pure secondary beams of lighter ions. Any specific isotope could be selected by the choice of the ion-optical parameters. The authors expect this device to be suited also for the separation of heavy-ion beams up to uranium, whereby high-resolution magnetic systems are needed in order to reach the separation limit given by the energy straggling in the intermediate energy absorber

  1. All-prism achromatic phase matching for tunable second-harmonic generation.

    Richman, B A; Bisson, S E; Trebino, R; Sidick, E; Jacobson, A

    1999-05-20

    Achromatic phase matching (APM) involves dispersing the light entering a nonlinear optical crystal so that a wide range of wavelengths is simultaneously phase matched. We constructed an APM apparatus consisting of six prisms, the final dispersion angle of which was optimized to match to second order in wavelength the type I phase-matching angle of beta barium borate (BBO). With this apparatus, we doubled tunable fundamental light from 620 to 700 nm in wavelength using a 4-mm-long BBO crystal. An analogous set of six prisms after the BBO crystal, optimized to second order in second-harmonic wavelength, realigned the output second-harmonic beams. Computer simulations predict that adjustment of a single prism can compensate angular misalignment of any or all the prisms before the crystal, and similarly for the prisms after the crystal. We demonstrated such compensation with the experimental device. The simulations also indicate that the phase-matching wavelength band can be shifted and optimized for different crystal lengths. PMID:18319927

  2. Elemental mapping in achromatic atomic-resolution energy-filtered transmission electron microscopy

    Forbes, B.D. [School of Physics, University of Melbourne, Parkville, VIC 3010 (Australia); Houben, L. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Gruenberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany); Mayer, J. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Gruenberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany); Central Facility for Electron Microscopy, RWTH Aachen University, D-52074 Aachen (Germany); Dunin-Borkowski, R.E. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Gruenberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany); Allen, L.J., E-mail: lja@unimelb.edu.au [School of Physics, University of Melbourne, Parkville, VIC 3010 (Australia)

    2014-12-15

    We present atomic-resolution energy-filtered transmission electron microscopy (EFTEM) images obtained with the chromatic-aberration-corrected FEI Titan PICO at the Ernst-Ruska Centre, Jülich, Germany. We find qualitative agreement between experiment and simulation for the background-subtracted EFTEM images of the Ti–L{sub 2,3} and O–K edges for a specimen of SrTiO{sub 3} oriented down the [110] zone axis. The simulations utilize the transition potential formulation for inelastic scattering, which permits a detailed investigation of contributions to the EFTEM image. We find that energy-filtered images of the Ti–L{sub 2,3} and O–K edges are lattice images and that the background-subtracted core-loss maps may not be directly interpretable as elemental maps. Simulations show that this is a result of preservation of elastic contrast, whereby the qualitative details of the image are determined primarily by elastic, coherent scattering. We show that this effect places a constraint on the range of specimen thicknesses which could theoretically yield directly useful elemental maps. In general, interpretation of EFTEM images is ideally accompanied by detailed simulations. - Highlights: • Achromatic atomic-resolution EFTEM images were obtained for STO 〈110〉. • Simulations were in qualitative agreement with Ti–L{sub 2,3} and O–K edge maps. • The experimental EFTEM maps are not directly interpretable as elemental maps. • Image intensities are strongly determined by preservation of elastic contrast. • Interpretation of EFTEM images is ideally accompanied by detailed simulations.

  3. Modification of the code BEAMCORR, and some simulation results of the magnet and achromat misalignments for the SLC South Arc

    An important decision has been made regarding the correction scheme for the arcs leading to the adoption of the so called scheme I. In this scheme the beam position data are collected from single-plane x and y Beam Position Monitors (BPMs), which are placed in the drift spaces adjacent to the downstream D- and F-magnets correspondingly. Similarly, single-plane x and y correctors are used for moving the upstream end of the corresponding magnets. In the present simulation this scheme is used exclusively. The first order calculations performed by means of TRANSPORT appear to be unsatisfactory from the point of view of the beam spotsize at the interaction point (IP). In this note we describe the modification to our program BEAMCORR which employs second order calculations by means of the program TURTLE. We also present the results of the following simulations: (a) study of the effects of two different levels of magnet misalignment on the beam spotsize at IP, and comparison of the results with those obtained by means of the program DINGBAT; (b) study of disjoints between achromats (both the displacement of the adjacent ends and angular discontinuity between achromats)

  4. Design and imaging performance of achromatic diffractive/refractive X-ray and Gamma-ray Fresnel lenses

    Skinner, G K

    2004-01-01

    Achromatic combinations of a diffractive Phase Fresnel Lens and a refractive correcting element have been proposed for X-ray and gamma-ray astronomy and for microlithography, but considerations of absorption often dictate that the refractive component be given a stepped profile, resulting in a double Fresnel lens. The imaging performance of corrected Fresnel lenses, with and without `stepping' is investigated and the trade-off between resolution and useful bandwidth in different circumstances is discussed. Provided the focal ratio is large, correction lenses made of low atomic number materials can be used with X-rays in the range approximately 10--100 keV without stepping. The use of stepping extends the possibility of correction to higher aperture systems, to energies as low as a few kilo electron volts and to gamma-rays of $\\sim$ mega electron volt energy.

  5. Periodontal bone lesions

    In the course of life the periodontum is subject to changes which may be physiological or pathological. Intraoral radiographs give insight into the hard structures of the dentomaxillar region and provides information on lesions in the bone of the periodontum in that they show radiopacities and radiolucencies caused by such lesions. In this thesis the relation is investigated between the true shape and dimensions of periodontal bone lesions and their radiographic images. A method is developed and tested of making standardized and reproducible radiographs suitable for longitudinal studies of periodontal lesions. Also the possibility is demonstrated of an objective and reproducible interpretation of radiographic characteristics of periodontal bone lesions. (Auth.)

  6. Lesion activity assessment

    Ekstrand, K R; Zero, D T; Martignon, S;

    2009-01-01

    This chapter focusses on the probability of a caries lesion detected during a clinical examination being active (progressing) or arrested. Visual and tactile methods to assess primary coronal lesions and primary root lesions are considered. The evidence level is rated as low (R(w)), as there are...... response to cariogenic plaque as well as lesion arrest. Based on this understanding, different clinical scoring systems have been developed to assess the severity/depth and activity of lesions. A recent system has been devised by the International Caries Detection and Assessment System Committee. The...... literature suggests that there is a fair agreement between visual/tactile external scripts of caries and the severity/depth of the lesion. The reproducibility of the different systems is, in general, substantial. No single clinical predictor is able to reliably assess activity. However, a combination of...

  7. Plasmonic color-graded nanosystems with achromatic sub-wavelength architectures for light filtering and advanced SERS detection

    Proietti Zaccaria, Remo

    2016-03-09

    Plasmonic colour-graded systems are devices featuring a spatially variable plasmonic response over their surface. They are widely used as nanoscale colour filters; their typical size is small enough to allow integration with miniaturized electronic circuits paving the way to realize novel nanophotonic devices. Currently, most plasmonic colour-graded systems are intrinsically discrete, as their chromatic response exploits the tailored plasmon resonance of micro-architectures characterized by different size and/or geometry for each target colour. Here we report the realization of multifunctional plasmon-graded devices where continuously-graded chromatic response is achieved by smoothly tuning the composition of the resonator material while simultaneously maintaining an achromatic nanoscale geometry. The result is a new class of versatile materials: we show their application as plasmonic filters with a potential pixel size smaller than half of the exciting wavelength, but also as multiplexed surface-enhanced Raman spectroscopy (SERS) substrates. Many more implementations, like photovoltaic efficiency boosters or colour routers await, and will benefit from the low fabrication cost and intrinsic plasmonic flexibility of the presented systems.

  8. Imaging Pediatric Vascular Lesions.

    Nguyen, Tuyet A; Krakowski, Andrew C; Naheedy, John H; Kruk, Peter G; Friedlander, Sheila Fallon

    2015-12-01

    Vascular anomalies are commonly encountered in pediatric and dermatology practices. Most of these lesions are benign and easy to diagnose based on history and clinical exam alone. However, in some cases the diagnosis may not be clear. This may be of particular concern given that vascular anomalies may occasionally be associated with an underlying syndrome, congenital disease, or serious, life-threatening condition. Defining the type of vascular lesion early and correctly is particularly important to determine the optimal approach to management and treatment of each patient. The care of pediatric patients often requires collaboration from a multitude of specialties including pediatrics, dermatology, plastic surgery, radiology, ophthalmology, and neurology. Although early characterization of vascular lesions is important, consensus guidelines regarding the evaluation and imaging of vascular anomalies does not exist to date. Here, the authors provide an overview of pediatric vascular lesions, current classification systems for characterizing these lesions, the various imaging modalities available, and recommendations for appropriate imaging evaluation. PMID:26705446

  9. Imaging Pediatric Vascular Lesions

    Nguyen, Tuyet A.; Krakowski, Andrew C.; Naheedy, John H.; Kruk, Peter G.

    2015-01-01

    Vascular anomalies are commonly encountered in pediatric and dermatology practices. Most of these lesions are benign and easy to diagnose based on history and clinical exam alone. However, in some cases the diagnosis may not be clear. This may be of particular concern given that vascular anomalies may occasionally be associated with an underlying syndrome, congenital disease, or serious, life-threatening condition. Defining the type of vascular lesion early and correctly is particularly important to determine the optimal approach to management and treatment of each patient. The care of pediatric patients often requires collaboration from a multitude of specialties including pediatrics, dermatology, plastic surgery, radiology, ophthalmology, and neurology. Although early characterization of vascular lesions is important, consensus guidelines regarding the evaluation and imaging of vascular anomalies does not exist to date. Here, the authors provide an overview of pediatric vascular lesions, current classification systems for characterizing these lesions, the various imaging modalities available, and recommendations for appropriate imaging evaluation. PMID:26705446

  10. Reversible focal splenial lesions

    Gallucci, Massimo; Limbucci, Nicola [University of L' Aquila, Department of Radiology, S. Salvatore Hospital, L' Aquila (Italy); Paonessa, Amalia [Loreto Nuovo Hospital, Department of Neuroradiology, Napoli (Italy); Caranci, Ferdinando [Federico II University, Department of Neurological Sciences, Napoli (Italy)

    2007-07-15

    Reversible focal lesions in the splenium of the corpus callosum (SCC) have recently been reported.They are circumscribed and located in the median aspect of the SCC. On MRI, they are hyperintense on T2-W and iso-hypointense on T1-W sequences, with no contrast enhancement. On DWI, SCC lesions are hyperintense with low ADC values, reflecting restricted diffusion due to cytotoxic edema. The common element is the disappearance of imaging abnormalities with time, including normalization of DWI. Clinical improvement is often reported. The most established and frequent causes of reversible focal lesions of the SCC are viral encephalitis, antiepileptic drug toxicity/withdrawal and hypoglycemic encephalopathy. Many other causes have been reported, including traumatic axonal injury. The similar clinical and imaging features suggest a common mechanism induced by different pathological events leading to the same results. Edema and diffusion restriction in focal reversible lesions of the SCC have been attributed to excitotoxic mechanisms that can result from different mechanisms; no unifying relationship has been found to explain all the pathologies associated with SCC lesions. In our opinion, the similar imaging, clinical and prognostic aspects of these lesions depend on a high vulnerability of the SCC to excitotoxic edema and are less dependent on the underlying pathology. In this review, the relevant literature concerning reversible focal lesions in the SCC is analyzed and hypotheses about their pathogenesis are proposed. (orig.)

  11. Oral Lesions in Neonates

    Rao, Roopa S; Majumdar, Barnali; Jafer, Mohammed; Maralingannavar, Mahesh; Sukumaran, Anil

    2016-01-01

    ABSTRACT Oral lesions in neonates represent a wide range of diseases often creating apprehension and anxiety among parents. Early examination and prompt diagnosis can aid in prudent management and serve as baseline against the future course of the disease. The present review aims to enlist and describe the diagnostic features of commonly encountered oral lesions in neonates. How to cite this article: Patil S, Rao RS, Majumdar B, Jafer M, Maralingannavar M, Sukumaran A. Oral Lesions in Neonates. Int J Clin Pediatr Dent 2016;9(2):131-138. PMID:27365934

  12. Managing Carious Lesions

    Schwendicke, F; Frencken, J E; Bjørndal, L;

    2016-01-01

    The International Caries Consensus Collaboration undertook a consensus process and here presents clinical recommendations for carious tissue removal and managing cavitated carious lesions, including restoration, based on texture of demineralized dentine. Dentists should manage the disease dental...... caries and control activity of existing cavitated lesions to preserve hard tissues and retain teeth long-term. Entering the restorative cycle should be avoided as far as possible. Controlling the disease in cavitated carious lesions should be attempted using methods which are aimed at biofilm removal or...... permanent teeth,selective removal to soft dentineshould be performed, although in permanent teeth,stepwise removalis an option. The evidence and, therefore, these recommendations support less invasive carious lesion management, delaying entry to, and slowing down, the restorative cycle by preserving tooth...

  13. Diffuse cavitary lung lesions

    Grunzke, Mindy; Garrington, Timothy [University of Colorado Denver, Department of Pediatrics, Aurora, CO (United States); The Children' s Hospital, Rick Wilson Center for Cancer and Blood Disorders, Aurora, CO (United States); Hayes, Kari [The Children' s Hospital, Pediatric Radiology, Aurora, CO (United States); Bourland, Wendy [Children' s Hospital at St. Francis, Warren Clinic, Inc., Tulsa, OK (United States)

    2010-02-15

    An 11-year-old girl presented with a 2-month history of progressively worsening cough, daily fevers, and weight loss. A chest radiograph revealed multiple cystic cavitary lung lesions. An extensive infectious work-up was negative. Chest CT verified multiple cavitary lung lesions bilaterally, and [F-18]2-fluoro-2-deoxy-D-glucose ({sup 18}F-FDG) positron emission tomography with CT (PET/CT) showed increased uptake in the lung lesions as well as regional lymph nodes. Subsequent biopsy of an involved lymph node confirmed classical Hodgkin lymphoma, nodular sclerosis type. This case represents an unusual presentation for a child with Hodgkin lymphoma and demonstrates a role for {sup 18}F-FDG PET/CT in evaluating a child with cavitary lung lesions. (orig.)

  14. Hypervascular liver lesions.

    Kamaya, Aya; Maturen, Katherine E; Tye, Grace A; Liu, Yueyi I; Parti, Naveen N; Desser, Terry S

    2009-10-01

    Hypervascular hepatocellular lesions include both benign and malignant etiologies. In the benign category, focal nodular hyperplasia and adenoma are typically hypervascular. In addition, some regenerative nodules in cirrhosis may be hypervascular. Malignant hypervascular primary hepatocellular lesions include hepatocellular carcinoma, fibrolamellar carcinoma, and peripheral cholangiocarcinoma. Vascular liver lesions often appear hypervascular because they tend to follow the enhancement of the blood pool; these include hemangiomas, arteriovenous malformations, angiosarcomas, and peliosis. While most gastrointestinal malignancies that metastasize to the liver will appear hypovascular on arterial and portal-venous phase imaging, certain cancers such as metastatic neuroendocrine tumors (including pancreatic neuroendocrine tumors, carcinoid, and gastrointestinal stromal tumors) tend to produce hypervascular metastases due to the greater recruitment of arterial blood supply. Finally, rare hepatic lesions such as glomus tumor and inflammatory pseudotumor may have a hypervascular appearance. PMID:19842564

  15. Lesiones deportivas Sports injuries

    Isabel Cristina Gallego Ching; Santiago Patiño Giraldo; Elkín Arango V.; Mónica Paola Clavijo Rodríguez; Jorge Alberto Osorio Ciro

    2007-01-01

    El estrés generado por la práctica deportiva ha originado una mayor probabilidad de que los atletas presenten lesiones agudas y crónicas. En el ámbito mundial existen diferentes investigaciones acerca de la incidencia de lesiones deportivas. La comparación de sus resultados es difícil por las diferencias en las características de la población y en la forma de reportar los datos, que varía ampliamente entre los estudios (proporciones o tasas de incidencia o tasas por cada 100 ó 1.000 participa...

  16. Relations among traumatic subdural lesions.

    Lee, K. S.; Doh, J. W.; Bae, H. G.; Yun, I. G.

    1996-01-01

    Acute subdural hematoma (ASDH), chronic subdural hematoma (CSDH) and subdural hygroma (SDG) occur in the subdural space, usually after trauma. We tried to find a certain relationship among these three traumatic subdural lesions in 436 consecutive patients. We included all subdural lesions regardless of whether they were main or not. We evaluated the distribution, age incidence and interval from injury to diagnosis of these lesions, and the frequency of new subdural lesions in each lesion. ASD...

  17. Genital lesions following bestiality

    Mittal A; Shenoi Shrutakirthi; Kumar K; Sharma PS

    2000-01-01

    A 48-year-old man presented with painful genital lesions with history of bestiality and abnor-mal sexual behaviour. Examination revealed multiple irregular tender ulcers and erosions, with phimosis and left sided tender inguinal adenopathy. VDRL, TPHA, HIV-ELISA were negative. He was treated with ciprofloxacin 500mg b.d. along with saline compresses with complete resolution.

  18. Genital lesions following bestiality

    Mittal A

    2000-01-01

    Full Text Available A 48-year-old man presented with painful genital lesions with history of bestiality and abnor-mal sexual behaviour. Examination revealed multiple irregular tender ulcers and erosions, with phimosis and left sided tender inguinal adenopathy. VDRL, TPHA, HIV-ELISA were negative. He was treated with ciprofloxacin 500mg b.d. along with saline compresses with complete resolution.

  19. Morel-Lavallee lesion

    Li Hui; Zhang Fangjie; Lei Guanghua

    2014-01-01

    Objective To review current knowledge of the Morel-Lavallee lesion (MLL) to help clinicians become familiar with this entity.Familiarization may decrease missed diagnoses and misdiagnoses.It could also help steer the clinician to the proper treatment choice.Data sources A search was performed via PubMed and EMBASE from 1966 to July 2013 using the following keywords:Morel-Lavallee lesion,closed degloving injury,concealed degloving injury,Morel-Lavallee effusion,Morel-Lavallee hematoma,posttraumatic pseudocyst,posttraumatic soft tissue cyst.Study selection Chinese and English language literatures relevant to the subject were collected.Their references were also reviewed.Results Morel-Lavallee lesion is a relatively rare condition involving a closed degloving injury.It is characterized by a filled cystic cavity created by separation of the subcutaneous tissue from the underlying fascia.Apart from the classic location over the region of the greater trochanter,MLLs have been described in other parts of the body.The natural history of MLL has not yet been established.The lesion may decrease in volume,remain stable,enlarge progressively or show a recurrent pattern.Diagnosis of MLL was often missed or delayed.Ultrasonography,computed tomography,and magnetic resonance imaging have great value in the diagnosis of MLL.Treatment of MLL has included compression,local aspiration,open debridement,and sclerodesis.No standard treatment has been established.Conclusions A diagnosis of MLL should be suspected when a soft,fluctuant area of skin or chronic recurrent fluid collection is found in a region exposed to a previous shear injury.Clinicians and radiologists should be aware of both the acute and chronic appearances to make the correct diagnosis.Treatment decisions should base on association with fractures,the condition of the lesion,symptom and desire of the patient.

  20. Demyelinative chiamal lesions.

    Spector, R H; Glaser, J S; Schatz, N J

    1980-12-01

    To clarify the clinical syndrome of demyelinative chiasmal involvement, six case histories were analyzed and the literature was reviewed. This entitity is characterized by especial predilection for women in the third to fifth decades; visual deficites of a chiasmal pattern that may be modest to marked, with a generallly good prognosis for functional recovery; and other signs and symptoms, not necessarily severe, of scattered lesions of the neuraxis. Neuroradiological studies, especially laminography of the sellar area and computerized tomography, must be employed to rule out a suprasellar mass lesion. The efficacy of systemic corticosteroid therapy is moot, but it seems reasonable to use such agents during acute stages, especially where vision is severely reduced on both sides. PMID:7447764

  1. Asymptomatic ischemic cerebral lesions

    For the purpose of studying the incidence, pathomorphology and etiology of asymptomatic ischemic cerebral lesions, we carried out a brain MRI study on 65 patients with diabetes mellitus accompanied with hypertension who are thought to belong to a high risk group of ischemic cerebrovascular diseases. Excluding the abnormality of tendon reflex due to diabetic neuropathy, sixty percent of the total patients had some mild neurological signs and symptoms, most of them was discrepancy in tendon reflex. The percentage of the patients in whom MRI disclosed some abnormalities was as high as 70%, they were lacunar stroke, multiple lacunar state, cortical infarct, and patchy high signal lesions visible only in the T2 weighted image. Lacunes or these patchy high signal lesions (considered to be the dilatation of the perivascular space or true lacunes) tended to be found along the border zone or the terminal zone. These results indicate that asymptomatic patients in whom MRI discloses the abnormalities should be considered as candidates for the future onset of multi-infarct. (author)

  2. Atypical idiopathic inflammatory demyelinating lesions

    Wallner-Blazek, Mirja; Rovira, Alex; Fillipp, Massimo; Rocca, Mara A; Miller, Andrew David; Schmierer, Klaus; Frederiksen, Jette; Gass, Achim; Gama, Hugo; Tilbery, Charles P; Rocha, Antonio J; Flores, José; Barkhof, Frederik; Seewann, Alexandra; Palace, Jacqueline; Yousry, Tarek; Montalban, Xavier; Enzinger, Christian; Fazekas, Franz

    2013-01-01

    Atypical lesions of a presumably idiopathic inflammatory demyelinating origin present quite variably and may pose diagnostic problems. The subsequent clinical course is also uncertain. We, therefore, wanted to clarify if atypical idiopathic inflammatory demyelinating lesions (AIIDLs) can be class...

  3. A disappearing neonatal skin lesion.

    Hawkes, Colin Patrick

    2012-01-31

    A preterm baby girl was noted at birth to have a firm, raised, non-tender skin lesion located over her right hip. She developed three similar smaller lesions on her ear, buttock and right knee. All lesions had resolved by 2 months of age.

  4. Lesiones deportivas Sports injuries

    Isabel Cristina Gallego Ching

    2007-04-01

    Full Text Available El estrés generado por la práctica deportiva ha originado una mayor probabilidad de que los atletas presenten lesiones agudas y crónicas. En el ámbito mundial existen diferentes investigaciones acerca de la incidencia de lesiones deportivas. La comparación de sus resultados es difícil por las diferencias en las características de la población y en la forma de reportar los datos, que varía ampliamente entre los estudios (proporciones o tasas de incidencia o tasas por cada 100 ó 1.000 participantes o tasas por horas de juego o por número de partidos jugados. Las tasas varían entre 1,7 y 53 lesiones por 1.000 horas de práctica deportiva, entre 0,8 y 90,9 por 1.000 horas de entrenamiento, entre 3,1 y 54,8 por 1.000 horas de competición y de 6,1 a 10,9 por 100 juegos. La gran variación entre las tasas de incidencia se explica por las diferencias existentes entre los deportes, los países, el nivel competitivo, las edades y la metodología empleada en los estudios. Se ha definido la lesión deportiva como la que ocurre cuando los atletas están expuestos a la práctica del deporte y se produce alteración o daño de un tejido, afectando el funcionamiento de la estructura. Los deportes de contacto generan mayor riesgo de presentar lesiones; se destacan al respecto los siguientes: fútbol, rugby, baloncesto, balonmano, artes marciales y jockey. Las lesiones ocurren con mayor probabilidad en las competencias que en el entrenamiento. Stress generated by sports practice has increased the probability that athletes suffer from acute and chronic injuries. Worldwide, there have been many different investigations concerning the incidence of sport injuries. The different ways in which results have been presented makes it difficult to compare among them. Rates of sports injuries vary between 1.7 and 53 per 1.000 hours of sports practice; 0.8 and 90.9 per 1.000 hours of training; 3.1 and 54.8 per 1.000 hours of competition, and 6.1 and 10.9 per 100

  5. Study of genital lesions

    Anand Kumar B

    2003-03-01

    Full Text Available A total of one hundred patients (75 males and 25 females age ranged from 17-65 years with genital lesions attending the STD clinic of Bowring and LC Hospitals Bangalore constituted the study group. Based on clinical features, the study groups were classified as syphilis (39, chancroid (30, herpes genitolis (13, condylomato lato (9, LGV (7t condylomata acuminata (5, genital scabies (3, granuloma inguinole (2 and genital candidiasis (1. In 68% microbiological findings confirmed the clinical diagnosis. Of the 100 cases 13% and 2% were positive for HIV antibodies and HbsAg respectively.

  6. Lesiones en corredores amateurs

    Natale, Vanesa

    2011-01-01

    Se realizó un estudio tomando como muestra a 100 corredores amateurs de la ciudad de Mar del Plata, en la cual el objetivo general fue determinar cuáles son las patologías más frecuentes en corredores. Correr no es solo un deporte en si mismo sino que tiene elementos de otras actividades deportivas, es decir, que las lesiones de los corredores también son comunes en otros tipos de deportes. El número de deportistas aumenta diariamente y al mismo tiempo aumentan el número de per...

  7. Mycetoma: Nonvenereal perineal lesions

    Gupta Shweta

    2010-01-01

    Full Text Available Mycetoma is a chronic, granulomatous disease of the skin, and subcutaneous tissue, which sometimes involves muscle, bones, and neighboring organs. It is characterized by tumefaction, abscess formation, and fistulae with discharge of grains from sinuses. Mycetoma can be caused by various species of fungi (eumycetoma and aerobic actinomycetes (actinomycetoma, which occur as saprophytes in soil or plants. A tentative diagnosis sufficient to initiate treatment may be made on the basis of grain color. For instance, melanoid grains are always caused by fungi and ochroid or pale grains by actinomycetes. Although this is not the thumbrule, there are exceptional reports too. As trauma favors infection, most lesions are on the foot and lower leg but they may occur anywhere on the body mimicking actinomycosis. However, lab investigations and culture are important tool to differentiate apart from the clinical picture. We are reporting atypical case with unusual site of presentation (perineum and thigh of mycetoma.

  8. Cystic lesions of the liver

    Rosado, E.; J Pereira; Bouchaibi, S; Bali, M

    2014-01-01

    LEARNING OBJECTIVES: To present the CT and MRI features of the cystic liver lesions, with emphasis on the differential diagnosis. BACKGROUND: Cystic liver lesions are a frequent finding in abdominal imaging and may represent a broad spectrum of entities, ranging from benign developmental cysts to malignant neoplasms. Radiological features of various cystic liver lesions frequently overlap. Therefore, it is necessary to integrate imaging with clinical and laboratorial findings. The most imp...

  9. Pigmented Lesions of the Vulva

    Gürol Açıkgöz; Çağlayan Çağdaş Demirci; Ercan Arca

    2012-01-01

    Pigmented lesions on the vulva are rare and their non specific features cause difficulties in their diagnosis and differential diagnosis. Because of their localization, it is difficult to follow up vulvar lesions, which are generally noticed coincidentally by patients. Vulvar pigmented lesions are classified clinically as macules/papules and patches/plaques to provide ease of the diagnosis. Nevi, angiokeratomas, seborrheic keratosis, melanoma, basal cell carcinoma and squamous cell carcinoma ...

  10. Microbiological aspects of endoperiodontal lesion

    Cristiane Tokunaga; Bruno Monguilhott Crozeta; Mariangela Schmitt Bonato; Beatriz Serrato Coelho; Flares Baratto-Filho; Flávia Sens Fagundes Tomazinho

    2013-01-01

    Introduction: The endoperiodontal lesion occurs when a tooth undergoing endodontic disease is united to a periodontal lesion with apical progression. Many times, the differential diagnosis between the endodontic and periodontal disease can be of difficult execution and the correct diagnosis and planing of the treatment is of main importance for a good prognosis Objective: To identify the main microorganisms within the lesion of endodontic and periodontal origin and correlate them with the en...

  11. Radio-induced brain lesions

    Gorgan Mircea Radu

    2014-03-01

    Full Text Available Introduction : Radiotherapy, an important tool in multimodal oncologic treatment, can cause radio-induced brain lesion development after a long period of time following irradiation.

  12. MALIGNANCY IN LARGE COLORECTAL LESIONS

    Carlos Eduardo Oliveira dos SANTOS

    2014-09-01

    Full Text Available Context The size of colorectal lesions, besides a risk factor for malignancy, is a predictor for deeper invasion Objectives To evaluate the malignancy of colorectal lesions ≥20 mm. Methods Between 2007 and 2011, 76 neoplasms ≥20 mm in 70 patients were analyzed Results The mean age of the patients was 67.4 years, and 41 were women. Mean lesion size was 24.7 mm ± 6.2 mm (range: 20 to 50 mm. Half of the neoplasms were polypoid and the other half were non-polypoid. Forty-two (55.3% lesions were located in the left colon, and 34 in the right colon. There was a high prevalence of III L (39.5% and IV (53.9% pit patterns. There were 72 adenomas and 4 adenocarcinomas. Malignancy was observed in 5.3% of the lesions. Thirty-three lesions presented advanced histology (adenomas with high-grade dysplasia or early adenocarcinoma, with no difference in morphology and site. Only one lesion (1.3% invaded the submucosa. Lesions larger than 30 mm had advanced histology (P = 0.001. The primary treatment was endoscopic resection, and invasive carcinoma was referred to surgery. Recurrence rate was 10.6%. Conclusions Large colorectal neoplasms showed a low rate of malignancy. Endoscopic treatment is an effective therapy for these lesions.

  13. IATROGENIC BILIARY LESIONS

    J. M. Schiappa

    2007-10-01

    Full Text Available Iatrogenic bile duct injury carries a high rate of morbidity. After the introduction of laparoscopiccholecystectomy the incidence of these injuries has at least doubled, and even after the learningcurve, the incidence has remained of about 0.5%. Etiology of the iatrogenic biliary injuries is theresult of the anatomical conditions (biliary or vascular anomalies, pathology (acute cholecystitis,adhesions, technical equipment, surgeon (the lerning curve. The type of the injuries, thediagnostic procedures and therapeutic approach are discussed. Most of the minor bile duct injuries,including cystic duct leaks and bile duct strictures, are well treatable with endoscopic techniques,whereas most of the major injuries require operative treatment, which at optimal circumstancesgives good results. Interdisciplinary cooperation and early referral to an experienced center iscrucial in the management of these iatrogenic lesions. The best „treatment” for this iatrogenicpathology is prevention: surgical access adapted to morphology, good exposure of the hepatoduodenalspace, good identification of structures before tying, appropriate dissection, selectivecholangiography, great care with the use of electrosurgery.

  14. Nonsurgical management of periapical lesions

    Fernandes Marina

    2010-01-01

    Full Text Available Periapical lesions develop as sequelae to pulp disease. They often occur without any episode of acute pain and are discovered on routine radiographic examination. The incidence of cysts within periapical lesions varies between 6 and 55%. The occurrence of periapical granulomas ranges between 9.3 and 87.1%, and of abscesses between 28.7 and 70.07%. It is accepted that all inflammatory periapical lesions should be initially treated with conservative nonsurgical procedures. Studies have reported a success rate of up to 85% after endodontic treatment of teeth with periapical lesions. A review of literature was performed by using electronic and hand searching methods for the nonsurgical management of periapical lesions. Various methods can be used in the nonsurgical management of periapical lesions: the conservative root canal treatment, decompression technique, active nonsurgical decompression technique, aspiration-irrigation technique, method using calcium hydroxide, Lesion Sterilization and Repair Therapy, and the Apexum procedure. Monitoring the healing of periapical lesions is essential through periodic follow-up examinations.

  15. Design and development of an ambient-temperature continuously-rotating achromatic half-wave plate for CMB polarization modulation on the POLARBEAR-2 experiment

    Hill, Charles A; Chinone, Yuji; Goeckner-Wald, Neil; Hazumi, Masashi; Keating, Brian; Kusaka, Akito; Lee, Adrian T; Matsuda, Frederick; Plambeck, Richard; Suzuki, Aritoki; Takakura, Satoru

    2016-01-01

    We describe the development of an ambient-temperature continuously-rotating half-wave plate (HWP) for study of the Cosmic Microwave Background (CMB) polarization by the POLARBEAR-2 (PB2) experiment. Rapid polarization modulation suppresses 1/f noise due to unpolarized atmospheric turbulence and improves sensitivity to degree-angular-scale CMB fluctuations where the inflationary gravitational wave signal is thought to exist. A HWP modulator rotates the input polarization signal and therefore allows a single polarimeter to measure both linear polarization states, eliminating systematic errors associated with differencing of orthogonal detectors. PB2 projects a 365-mm-diameter focal plane of 7,588 dichroic, 95/150 GHz transition-edge-sensor bolometers onto a 4-degree field of view that scans the sky at $\\sim$ 1 degree per second. We find that a 500-mm-diameter ambient-temperature sapphire achromatic HWP rotating at 2 Hz is a suitable polarization modulator for PB2. We present the design considerations for the PB...

  16. The Impact of the Spectral Response of an Achromatic Half-Wave Plate on the Measurement of the Cosmic Microwave Background Polarization

    Bao, C; Baccigalupi, C; Didier, J; Hanany, S; Jaffe, A; Johnson, B R; Leach, S; Matsumura, T; Miller, A; O'Dea, D

    2011-01-01

    We study the impact of the spectral dependence of the linear polarization rotation induced by an achromatic half-wave plate on measurements of cosmic microwave background polarization in the presence of astrophysical foregrounds. We focus on the systematic effects induced on the measurement of inflationary gravitational waves by uncertainties in the polarization and spectral index of Galactic dust. We find that for the experimental configuration and noise levels of the balloon-borne EBEX experiment, which has three frequency bands centered at 150, 250, and 410 GHz, a crude dust subtraction process mitigates systematic effects to below detectable levels for 10% polarized dust and tensor to scalar ratio of as low as r = 0.01. We also study the impact of uncertainties in the spectral response of the instrument. With a top-hat model of the spectral response for each band, characterized by band-center and band-width, and with the same crude dust subtraction process, we find that these parameters need to be determi...

  17. PHAEOHYPHOMYCOSIS: CUTANEOUS, SUBCUTANEOUS, NASOPHARYNGEAL LESIONS

    M. Rasoolinejad

    1999-06-01

    Full Text Available Phaeohyphomycosis is an amalgam of clinical diseases caused by a wide variety of dematiaceous fungi. We are reporting on a 16 year-old patient from Amol with subcutaneous cervical nodes and nasopharyngeal lesions of phaeohypho"nmycosis that were confirmed by pathological examination, direct smear, and culture. After treatment with an oral triazole (Itraconazole for 4 months, all nodes and lesions disappeared and treatment was stopped A new lesion appeared on his chest wall 8 months, therapy with itraconazole was restarted and commuted for a long time.

  18. Factitious lesions of the hand

    Ricardo Kaempf de Oliveira

    2013-08-01

    Full Text Available OBJECTIVE: The presence of a lesion with atypical presentation, obscure clinical history, which does not improve with classic treatments, shall raise the red flag of the medical team. In such cases, the hypothesis of a factitious lesion shall be considered. Many times the correct diagnosis on the initial assessment may avoid high-cost diagnostic tests, unnecessary treatments, and time consumption of the medical team. We present here two classic cases of factitious lesions that, similar to those described in the literature, is difficult to diagnose and difficult to treat.

  19. Nerve lesioning with direct current

    Ravid, E. Natalie; Shi Gan, Liu; Todd, Kathryn; Prochazka, Arthur

    2011-02-01

    Spastic hypertonus (muscle over-activity due to exaggerated stretch reflexes) often develops in people with stroke, cerebral palsy, multiple sclerosis and spinal cord injury. Lesioning of nerves, e.g. with phenol or botulinum toxin is widely performed to reduce spastic hypertonus. We have explored the use of direct electrical current (DC) to lesion peripheral nerves. In a series of animal experiments, DC reduced muscle force by controlled amounts and the reduction could last several months. We conclude that in some cases controlled DC lesioning may provide an effective alternative to the less controllable molecular treatments available today.

  20. Differential diagnosis of sacral lesions

    The authors reviewed the teaching files of Temple University Hospital and Children's Hospital of Philadelphia and selected the best representative cases of various lesions of the sacrum. They selected the following lesions: metastasis, chondrosarcoma, chrodoma, plasmacytoma, giant cell tumor, osteogenic sarcoma, Ewing sarcoma, neuroblastoma, neurofibrosarcoma, hemangiopericytoma, osteoblastoma, ossifying fibroma, eosinophilic granuloma, aneurysmal bone cyst, sacrococcygeal teratoma, anterior meningocele, endodermal sinus tumor, and stress fracture. The authors illustrate, for each lesion, the likely age range, sights of predilection, likelihood of occurrence in the sacrum, and radiographic findings helpful in limiting the differential diagnosis. They demonstrate the value of bone scintigraphy in detecting, and CT in confirming, stress fractures of the sacrum

  1. Traumatic lesions of pulmonary parenchyma

    Five cases of post-traumatic pulmonary lesions (contusion, laceration and hematoma) are presented. The pathophysiology, radiological aspects and differential diagnosis are reviewed. The benign evolution showing the absorption in short time, without medical interference is emphasized. (Author)

  2. Post-radiotherapeutic heart lesions

    Heart structures have traditionally been considered radioresistant. In fact all tissues subjected to radiotherapy can develop lesions. Possible damage includes: - pericardiac fibrosis, the commonest and best individualized, associated with a constriction this leads to a stoppage pattern usually occurring late, around the 18th month. Its frequency depends directly on the total radiation dose; - fibrous myocarditis by direct damage to the heart muscle; - stenosis type lesions of the large coronary trunks; - in exceptional cases lesions of the aorta: hyperplastic degenerescence of the intima and adventitia or of the aortic sigmoid valvules and the mitral valves. Three observations are reported, concerning a coronary, a pericardiac and a coronary, myocardiac and pericardiac lesion. Following this account the irradiation techniques and main experimental data are reviewed and the prophylactic and therapeutic consequences to be derived from our observations and those of the literature are examined

  3. MRI of Focal Liver Lesions.

    Albiin, Nils

    2012-05-01

    Magnetic resonance imaging, MRI has more advantages than ultrasound, computed tomography, CT, positron emission tomography, PET, or any other imaging modality in diagnosing focal hepatic masses. With a combination of basic T1 and T2 weighted sequences, diffusion weighted imaging, DWI, and hepatobiliary gadolinium contrast agents, that is gadobenate dimeglumine (Gd-BOPTA) and gadoxetic acid (Gd-EOB), most liver lesions can be adequately diagnosed. Benign lesions, as cyst, hemangioma, focal nodular hyperplasia, FNH or adenoma, can be distinguished from malignant lesions. In a non-cirrhotic liver, the most common malignant lesions are metastases which may be hypovascular or hypervascular. In the cirrhotic liver hepatocellular carcinoma, HCC, is of considerable importance. Besides, intrahepatic cholangiocarcinoma and other less common malignancies has to be assessed. In this review, the techniques and typical MRI features are presented as well as the new algorithm issued by American Association for the Study of the Liver Diseases (AASLD). PMID:23049491

  4. Rosacea with extensive extrafacial lesions

    Pereira, TM; Vieira, AP; Sousa-Basto, A.

    2008-01-01

    Rosacea is a very common skin disorder in the clinical practice that primarily affects the convex areas of the face. Extrafacial rosacea lesions have occasionally been described, but extensive involvement is exceptional. In the absence of its typical clinical or histological features, the diagnosis of extrafacial rosacea may be problematic. We describe an unusual case of rosacea with very exuberant extrafacial lesions, when compared with the limited involvement of the face.

  5. Cutaneous lesions of the nose

    Altmeyer Peter; Paech Volker; Thrandorf Christina; Sand Daniel; Sand Michael; Bechara Falk G

    2010-01-01

    Abstract Skin diseases on the nose are seen in a variety of medical disciplines. Dermatologists, otorhinolaryngologists, general practitioners and general plastic and dermatologic surgeons are regularly consulted regarding cutaneous lesions on the nose. This article is the second part of a review series dealing with cutaneous lesions on the head and face, which are frequently seen in daily practice by a dermatologic surgeon. In this review, we focus on those skin diseases on the nose where su...

  6. Unusual lesions of the mediastinum

    Fatima Shamsuddin

    2015-01-01

    Full Text Available Objectives: To study unusual lesions in the mediastinum, which do not originate from the thymus, lymph nodes, neural tissues or germ cells, and tissues that normally engender pathologic lesions in the mediastinum. Materials and Methods: Of the 65 cases seen, 12 unusual lesion were encountered in a 5½ year period from 2006 to 2011. Results: Two cases of nodular colloid goiter and one each of the mediastinal cyst, undifferentiated carcinoma, and Langerhans cell histiocytosis (LCH affected the anterosuperior mediastinum. In the middle mediastinum, one case each of the mesothelioma, malignant gastrointestinal stromal tumor (GIST, squamous cell carcinoma (SCC, solitary fibrous tumor (SFT, and pleomorphic sarcoma (PS was seen. One case of meningeal melanocytoma (Mme and primary pleural liposarcoma (PL involved the posterior mediastinum. Persistent disease was seen in LCH after 2 years. Of all the cases with malignant lesions, only the patient with SCC was alive after 1 year. Conclusion: The cases of primary and SCC, LCH, melanocytoma, liposarcoma and PS, and GIST are unexpected and very rarely have paradigms in the mediastinum. Radiologic impression and knowledge of the compartment where these lesions arose from hardly assisted in arriving at a definitive opinion as the lesions were not typical of this location. A high index of suspicion and the immunohistochemical profile facilitated the final diagnosis.

  7. Simulation of spiculated breast lesions

    Elangovan, Premkumar; Alrehily, Faisal; Pinto, R. Ferrari; Rashidnasab, Alaleh; Dance, David R.; Young, Kenneth C.; Wells, Kevin

    2016-03-01

    Virtual clinical trials are a promising new approach increasingly used for the evaluation and comparison of breast imaging modalities. A key component in such an assessment paradigm is the use of simulated pathology, in particular, simulation of lesions. Breast mass lesions can be generally classified into two categories based on their appearance; nonspiculated masses and spiculated masses. In our previous work, we have successfully simulated non-spiculated masses using a fractal growth process known as diffusion limited aggregation. In this new work, we have extended the DLA model to simulate spiculated lesions by using features extracted from patient DBT images containing spiculated lesions. The features extracted included spicule length, width, curvature and distribution. This information was used to simulate realistic looking spicules which were attached to the surface of a DLA mass to produce a spiculated mass. A batch of simulated spiculated masses was inserted into normal patient images and presented to an experienced radiologist for review. The study yielded promising results with the radiologist rating 60% of simulated lesions in 2D and 50% of simulated lesions in DBT as realistic.

  8. Cystic parotid gland lesion evaluation

    We evaluated differential diagnoses of cystic parotid gland lesions and the efficacy of preoperative diagnosis. Of 191 parotid gland nodules resected between January 2003 and October 2008, 167 (87%) were benign and 24 (13%) malignant. Thirty-five parotid gland nodules whose components were almost cystic were enrolled in this study. All cystic lesions were retrospectively evaluated with respect to preoperative diagnostic examinations and histopathological confirmed diagnosis. Cystic components in surgical specimens were also evaluated histopathologically. The relationships with magnetic resonance imaging (MRI) findings and histopathological confirmed diagnosis were studied. Of 35 cystic lesions, 11 were complete cystic masses and had no mural nodules, while remaining 24 were incomplete and had mural nodules. Histopathological examinations showed that 5 were nonneoplastic, 27 were cystic degenerations of benign tumors, and 3 were cystic degenerations of malignant tumors. In the 11 complete cysts, preoperative diagnosis could not be made using any modality, whether with fine needle aspiration cytology (FNAC), salivary scintigraphy, or 67-gallium citrate scintigraphy. Of 24 incomplete cysts, only 9 cystic Warthin tumors were diagnosed correctly before surgery. Studies of cystic components in MRI and histopathology suggested that hemorrhagic degeneration of malignant tumors should be kept in mind for cystic lesions showing hemorrhagic portions. Cystic parotid gland lesions are difficult to diagnose correctly before surgery, but the evaluation of cystic components by MRI and FNAC is helpful in differentiating between benign and malignant tumors. (author)

  9. Renal lesions of nondomestic felids.

    Newkirk, K M; Newman, S J; White, L A; Rohrbach, B W; Ramsay, E C

    2011-05-01

    To comprehensively evaluate the occurrence of renal lesions in a variety of nondomestic felids, necropsy cases from 1978 to 2008 were reviewed from a municipal zoo and a large cat sanctuary for those in which the kidneys were examined histologically. Seventy exotic felids were identified (25 tigers, 18 lions, 6 cougars, 5 leopards, 3 snow leopards, 3 clouded leopards, 3 Canadian lynx, 2 ocelots, 2 bobcats, 2 cheetahs, 1 jaguar), and their histologic renal lesions were evaluated and compared. The most common lesion was tubulointerstitial nephritis (TIN); 36 of 70 (51%) cats were affected to some degree. Lymphocytic interstitial nephritis was the most common lesion in the tigers (9 of 25, 36%) and was rarely seen in other species. Although the renal pelvis was not available for all cats, 28 of 47 (60%) had some degree of lymphocytic pyelitis. There was no significant association between the presence of pyelitis and that of TIN. Only 1 cat had pyelonephritis. Renal papillary necrosis was present in 13 of 70 (19%) cats and was significantly associated with historical nonsteroidal anti-inflammatory drug treatment (odds ratio, 7.1; 95% confidence interval, 1.9 to 26.8). Only 1 cat (lion) had amyloid accumulation, and it was restricted to the corticomedullary junction. Primary glomerular lesions were absent in all cats. Intraepithelial pigment was identified in many of the cats but was not correlated with severity of TIN. Despite several previous reports describing primary glomerular disease or renal amyloidosis in exotic felids, these lesions were rare to absent in this population. PMID:20876911

  10. Lesions of juxtacortical origin (surface lesions of bone)

    Kenan, S. (Dept. of Orthopaedics, Mount Sinai School of Medicine, New York, NY (United States)); Abdelwahab, I.F. (Dept. of Radiology, Mount Sinai School of Medicine, New York, NY (United States)); Klein, M.J. (Dept. of Pathology, Mount Sinai School of Medicine, New York, NY (United States)); Hermann, G. (Dept. of Radiology, Mount Sinai School of Medicine, New York, NY (United States)); Lewis, M.M. (Dept. of Orthopaedics, Mount Sinai School of Medicine, New York, NY (United States))

    1993-01-01

    A large variety of tumor and tumor-like conditions have been shown to originate from the surface of bone. Most surface lesions are associated with periosteal reaction. The periosteum is a multipotential membrane. Its cellular composition may give rise to a variety of both neoplasms and tumor-like conditions. To avoid misinterpretation, the orthopedist, radiologist, and pathologist should be familiar with the entire spectrum of surface lesions. A better understanding of the natural history and biological behavior at different lesional maturity stages and correlation of the history with the radiographic and pathological findings is essential to establish the correct diagnosis. A history of injury of blunt trauma is very important. A stress fracture may produce a periosteal reaction acd callus that can be difficult to distinguish from osteosarcoma. In this review article, the authors wish to describe and define each term by its anatomy and radiographic features while discussing the entire spectrum of surface lesions. All the illustrative cases in this review article have been proven histologically. (orig.)

  11. Localized lesions in secondary syphillis

    The clinical manifestations of secondary syphilis are variable and can mimic many skin diseases, mostly being generalized and symmetrical in distribution. Localized lesions of secondary syphilis are rarely seen in dermatology clinics. We report an unusual presentation wherein a patient had localized lesions over face and soles only. There is a need for increased awareness on the part of physicians to recognize new patterns of syphilitic infection, together with a willingness to consider the diagnosis of syphilis in patients with unusual clinical features. (author)

  12. Lesion detectability in digital radiography

    Gagne, Robert M.; Boswell, Jonathan S.; Myers, Kyle J.; Peter, Guillaume

    2001-06-01

    The usefulness of Fourier-based measures of imaging performance has come into question for the evaluation of digital imaging systems. Figures of merit such as detective quantum efficiency are relevant for linear, shift-invariant systems with stationary noise. However, no digital imaging system is shift invariant, and realistic images do not satisfy the stationarity condition. Our methods for task- based evaluation of imaging systems, based on lesion detectability, do not require such assumptions. We have computed the performance of Hotelling and nonprewhitening matched-filter observers for the task of lesion detection in digital radiography.

  13. The Essex-Lopresti lesion

    Wegmann, K.; Dargel, J; Burkhart, K. J.; Brüggemann, G. P.; Müller, L. P.

    2012-01-01

    The Essex-Lopresti lesion represents a severe injury of the forearm unit. In the 1940s, it’s pathology and consequences have already been mentioned by several authors. Over the course of time, the pathophysiology of the lesion was displayed in more detail. Therefore, an intensive analysis of the involved anatomic structures was done. The interosseous membrane was shown to play a major role in stabilising the forearm unit, in the situation of a fractured radial head, which is the primary stabi...

  14. Lesiones frecuentes en atletas profesionales

    Doyel, Crevecoer

    2015-01-01

    Durante la práctica del atletismo frecuentemente ocurren lesiones, afectando principalmente a los miembros inferiores. Las causas que las originan son muy diversas y tienen diferentes características de acuerdo al tipo de modalidad realizada dentro del atletismo. Objetivo: Analizar las características de las lesiones más frecuentes en miembros inferiores, en atletas corredores profesionales, de diferentes distancias, de ambos sexos, de entre 18 y 40 años de edad, que practican atletismo en...

  15. Flexibilidad y lesiones de futbolistas

    Gocebate, Verónica

    2014-01-01

    Cabe destacar que en deporte se requiere de una correcta preparación física y el caso del fútbol no es diferente a cualquier otro. Este es un deporte en equipo que genera un desgaste físico y mental en cada partido en el cual se pueden sufrir diferentes lesiones. Son varios los factores que predisponen a que se produzcan lesiones, por lo que es importante un correcto entrenamiento diario. Objetivo: Determinar la relación entre los niveles de flexibilidad de la cadena muscula...

  16. Disseminated paracoccidioidomycosis diagnosis based on oral lesions

    Liana Preto Webber

    2014-01-01

    Full Text Available Paracoccidioidomycosis (PCM is a deep mycosis with primary lung manifestations that may present cutaneous and oral lesions. Oral lesions mimic other infectious diseases or even squamous cell carcinoma, clinically and microscopically. Sometimes, the dentist is the first to detect the disease, because lung lesions are asymptomatic, or even misdiagnosed. An unusual case of PCM with 5 months of evolution presenting pulmonary, oral, and cutaneous lesions that was diagnosed by the dentist based on oral lesions is presented and discussed.

  17. Imaging inflammatory acne: lesion detection and tracking

    Cula, Gabriela O.; Bargo, Paulo R.; Kollias, Nikiforos

    2010-02-01

    It is known that effectiveness of acne treatment increases when the lesions are detected earlier, before they could progress into mature wound-like lesions, which lead to scarring and discoloration. However, little is known about the evolution of acne from early signs until after the lesion heals. In this work we computationally characterize the evolution of inflammatory acne lesions, based on analyzing cross-polarized images that document acne-prone facial skin over time. Taking skin images over time, and being able to follow skin features in these images present serious challenges, due to change in the appearance of skin, difficulty in repositioning the subject, involuntary movement such as breathing. A computational technique for automatic detection of lesions by separating the background normal skin from the acne lesions, based on fitting Gaussian distributions to the intensity histograms, is presented. In order to track and quantify the evolution of lesions, in terms of the degree of progress or regress, we designed a study to capture facial skin images from an acne-prone young individual, followed over the course of 3 different time points. Based on the behavior of the lesions between two consecutive time points, the automatically detected lesions are classified in four categories: new lesions, resolved lesions (i.e. lesions that disappear completely), lesions that are progressing, and lesions that are regressing (i.e. lesions in the process of healing). The classification our methods achieve correlates well with visual inspection of a trained human grader.

  18. Secondary syphilis lesions resembling pityriasis

    This case report describes a male patient who presented with generalized, centrally-ulcerated papules with crusts and hypopigmented macules. Initially, differential diagnostic considerations included pityriasis lichenoides but the serology for syphilis was positive and there was a rapid response to penicillin with clearing of the lesions at the end of three weeks treatment. (author)

  19. Odontogenic lesions in pediatric patients.

    Fang, Qi-Gen; Shi, Shuang; Sun, Chang-Fu

    2014-05-01

    The purpose was to evaluate our 20-year experience of pediatric odontogenic lesions. Pediatric patients with a diagnosis of odontogenic lesion were identified. Three hundred ten patients were odontogenic; dentigerous cyst was seen in 62.0% of the cases. Most (70.2%) of them occurred in mixed dentition period, and it had a male preponderance. Odontogenic keratocystic tumor occurred in the permanent dentition period. It had an equal site distribution. Odontoma was seen in 20.0% of the cases. Its site of predilection was the mandible. Ameloblastoma was the most common odontogenic tumor. Most of the cases occurred in the permanent dentition period. It affected the male and female equally. Calcifying epithelioma odontogenic tumor was seen in 11.8% of the cases. All the lesions occurred in the primary dentition period. It had no sex or site preponderance. Myxoma was seen in 3.6% of the cases. It was most common in the permanent dentition period, and it was more frequent in the male. Iliac crest bone graft was successfully performed in 28 patients, postoperative infection occurred in 2 patients, and no donor-site dysfunctions were reported. The observed differences in lesion type and distribution in this study compared with previous researches may be attributable to genetic and geographic variation in the populations studied. Iliac crest bone graft was suggested for pediatric mandible reconstruction. PMID:24785745

  20. Pigmented Lesions of the Vulva

    Gürol Açıkgöz

    2012-06-01

    Full Text Available Pigmented lesions on the vulva are rare and their non specific features cause difficulties in their diagnosis and differential diagnosis. Because of their localization, it is difficult to follow up vulvar lesions, which are generally noticed coincidentally by patients. Vulvar pigmented lesions are classified clinically as macules/papules and patches/plaques to provide ease of the diagnosis. Nevi, angiokeratomas, seborrheic keratosis, melanoma, basal cell carcinoma and squamous cell carcinoma are classified under the macules/papules, and post-inflammatory hyperpigmentation, physiological hyperpigmentation, melanosis and acanthosis nigricans are classified under the patch/plaque. Dermatoscopic examination, which is increasing recently, is very valuable for avoiding possible cosmetic and functional complications of surgical procedures. However, epidermal pigmentations such as vulvar melanosis and vulvar intraepitelyal neoplazi are dermatoscopically indistinguishable. It may also be difficult to diagnose vulvar melanoma clinically and dermatoscopically. Histological examination is the gold standard for the diagnosis of pigmented vulvar lesions, which are clinically and dermatoscopically indistinguishable. (Turk J Dermatol 2012; 6: 39-44

  1. Microbiological aspects of endoperiodontal lesion

    Cristiane Tokunaga

    2013-06-01

    Full Text Available Introduction: The endoperiodontal lesion occurs when a tooth undergoing endodontic disease is united to a periodontal lesion with apical progression. Many times, the differential diagnosis between the endodontic and periodontal disease can be of difficult execution and the correct diagnosis and planing of the treatment is of main importance for a good prognosis Objective: To identify the main microorganisms within the lesion of endodontic and periodontal origin and correlate them with the endoperiodontal lesion. Literature review: The search strategy comprised the electronic studies of databases such as PubMed and Cochrane on the microbiology of the endodontic and periodontal systems through employing the following keywords: microbiology, endodontics, periodontal pocket. Results: There were similarities in the endodontic and periodontal microflora. However, the number of microorganisms within the cross infection is limited, including Bacteroides, Eubacteria, Fusobacteria, spirochaetes, Wolinella. The bacterias forming the red complex are closely related to the severity of the periodontal disease and can also participate in the pathogenesis of the periradicular abscesses. Conclusion: There are many communication routes between the periodontium and pulpal tissue, therefore the contamination from um tissue to another can occur, existing a microbiological inter-relationship between these tissues.

  2. Stereotactic lesioning for mental illness

    The authors report stereotactically created lesioning by radiofrequency or Cyberknife radiosurgery for patients with mental illness. Since 1993, thirty-eight patients have undergone stereotactic psychosurgery for medically intractable mental illnesses. Two patients had aggressive behavior. Twenty-five patients suffered from Obsessive-Compulsive Disorder (OCD) and ten patients had depression. Another patient suffered from atypical psychosis. Bilateral amygdalotomy and subcaudate tractotomy were done for aggressive behavior. Limbic leucotomy or anterior cingulotomy was done for CCD and subcaudate tractotomy with or without cingulotomy was done for depression. In twenty-three patients, the lesions were made by a radiofrequency (RF) lesion generator. In fifteen cases, the lesions were made with Cyberknife Radiosurgery (CKRS). The Overt Aggression Scale (OAS) declined from 8 to 2 with clinical improvement during follow up period. With long-term follow up (meaning 57 months) in 25 OCDs, the mean Yale Brown Obsessive Compulsive Score (YBOCS) declined from 34 to 13 (n = 25). The Hamilton Depression scale (HAMD) for ten patients with depression declined from 38.5 to 10.5 (n = 10). There was no operative mortality and no significant morbidity except one case with transient urinary incontinence. Authors suggest that stereotactic psychosurgery by RF and CKRS could be a safe and effective means of treating some medically intractable mental illnesses. (author)

  3. Imaging of Chest Wall Lesions in Children

    A. Hekmatnia

    2008-01-01

    Full Text Available Chest wall lesions in childhood include a wide range of pathologies; Benign lesions include lipoma, neurofibroma, lymphangioma, hemangioma, and mesenchymal hamartoma."nMalignant lesions include Neuroblastoma, Rhabdo-myosarcoma, Ewing sarcoma, and Askin tumor."nSystemic diseases such as leukemia, lymphoma, Langerhans cell histiocytosis, and also infections such as tuberculosis, and actinomycosis may also cause chest wall lesions."nThe imaging characteristics of these lesions are re-viewed, but only a minority of the lesions shows diagnostic imaging features, and most of lesions re-quire biopsy and histopathological examination for "ndefinitive diagnosis."nThe role of different modalities is discussed with an emphasis on magnetic resonance imaging for demonstrating lesion morphology and local spread. Computed tomography and neuclear medicine being used mainly to assess remote disease."nIn this lecture, we discuss about imaging of chest wall lesions in children.

  4. Petrous apex lesions in the pediatric population

    Radhakrishnan, Rupa [University of Cincinnati College of Medicine, Department of Radiology, Cincinnati, OH (United States); Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Son, Hwa Jung [University of Cincinnati College of Medicine, Department of Otolaryngology-Head and Neck Surgery, Cincinnati, OH (United States); Koch, Bernadette L. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States)

    2014-03-15

    A variety of abnormal imaging findings of the petrous apex are encountered in children. Many petrous apex lesions are identified incidentally while images of the brain or head and neck are being obtained for indications unrelated to the temporal bone. Differential considerations of petrous apex lesions in children include ''leave me alone'' lesions, infectious or inflammatory lesions, fibro-osseous lesions, neoplasms and neoplasm-like lesions, as well as a few rare miscellaneous conditions. Some lesions are similar to those encountered in adults, and some are unique to children. Langerhans cell histiocytosis (LCH) and primary and metastatic pediatric malignancies such as neuroblastoma, rhabomyosarcoma and Ewing sarcoma are more likely to be encountered in children. Lesions such as petrous apex cholesterol granuloma, cholesteatoma and chondrosarcoma are more common in adults and are rarely a diagnostic consideration in children. We present a comprehensive pictorial review of CT and MRI appearances of pediatric petrous apex lesions. (orig.)

  5. Lethal, potentially lethal lesion model

    Curtis, S.B.

    1983-07-01

    A theoretical framework to describe the formation of lethal mutations by radiation is presented. Lesions that are repaired (and misrepaired) in each type of experiment described (delayed plating and split dose) are assumed to be the same. In this model the same (potentially lethal) lesions cause both sublethal and potentially lethal damage. Potentially lethal damage is defined as damage which may be modified by alterations in postirradiation conditions. Sublethal damage is cellular damage whose accumulation may lead to lethality. A crucial consideration in the expression of the damage is the kind of medium in which the cells are placed during the repair period. Fresh or growth medium (F-medium) is assumed to cause fixation of damage after about 3 hours, while no fixation (only misrepair) occurs in conditioned medium (C-medium).

  6. Cytologic diagnosis of pulmonary lesions.

    Rossi, Esther Diana; Mulè, Antonino; Maggiore, Claudia; Miraglia, Antonella; Lauriola, Libero; Vecchio, Fabio Maria; Fadda, Guido

    2004-01-01

    The major types of cytologic preparations used in most laboratories to detect the lesions of the lower respiratory tract (LRT) are examined. These methods include sputum, bronchial washing, bronchial brushing, bronchoalveolar lavage (BAL) and fine-needle aspiration biopsy (FNAB). Sputum represents the simplest and most cost-effective sampling method even though fiberoptic bronchoscopy and radiologic guided FNAB are superseding it as the first diagnostic choice in most cases. There are advantages and disadvantages associated with each technique:bronchial brushing and FNABs tend to preserve both the cellular details and their architectural arrangement whereas sputum and bronchial washing often cause a variable degree of cellular degeneration and fragmentation. As a result, most pulmonary lesions may be detected and correctly diagnosed if multiple techniques are used to acquire diagnostic material. CT-guided FNAB represents the most effective method to achieve a correct diagnosis in pulmonary tumors. PMID:15852720

  7. Implant periapical lesion. Case report

    Gregory Venetis, Fotis Iordanidis, Paraskevi Giovani, Lambros Zouloumis

    2011-01-01

    Ιmplant periapical lesion (IPL) is probably not a uniform entity in all cases presented in the literature. Asseptic bone necrosis may be a cause for some of the IPLs, whilst the presence of microorganisms is not always detectable with conventional methods. A case of IPL in a male patient who underwent an extraction of 12 tooth and an immediate implantation at this site is presented. Eight months postoperatively, an IPL was revealed on radiologic examination. After surgical exploration, the IP...

  8. Cystic Lesions in Autoimmune Pancreatitis

    Gompertz, Macarena; Morales, Claudia; Aldana, Hernán; Castillo, Jaime; Berger, Zoltán

    2015-01-01

    Autoimmune pancreatitis (AIP) can be chronic or recurrent, but frequently completely reversible after steroid treatment. A cystic lesion in AIP is a rare finding, and it can mimic a pancreatic cystic neoplasm. Difficulties in an exact diagnosis interfere with treatment, and surgery cannot be avoided in some cases. We report the history of a 63-year-old male presenting with jaundice and pruritus. AIP was confirmed by imaging and elevated IgG4 blood levels, and the patient completely recovered ...

  9. Symmetrical thalamic lesions in infants.

    Eicke, M.; Briner, J; Willi, U; Uehlinger, J; Boltshauser, E

    1992-01-01

    Clinical observations and findings on imaging are reported in six newborns with symmetrical thalamic lesions (STL). In three cases the diagnosis was confirmed by postmortem examination. Characteristic observations in this series and 17 previously reported cases include no evidence of perinatal asphyxia, high incidence of polyhydramnios, absent suck and swallow, absent primitive reflexes, appreciable spasticity at or within days of birth, lack of psychomotor development, and death within days ...

  10. Radiological diagnosis of adrenal lesions

    Among all the radiological examination techniques, CT is today, besides scintigraphy, the method of choice as far as the detection of functional adrenal lesions is concerned. In primary aldosteronism, CT classification of the syndrome is based on the detection of an adenoma which can be reliably detected in adenoma sizes up to 8-10 mm. Thus, 70 to 80% of Conn's syndromes can be classified. In adrenal Cushing's syndrome, the distinction between adenoma and carcinoma of the adrenal gland is up to CT and can usually be easily made due to the characteristic morphology of each type of lesion. In case of a typcial adrenal or juxtaadrenal tumor location, detection of a pheochromocytoma is likewise easy. In ectopic and multiple pheochromocytomas or such as occur as part of a MEN-syndrome, the situation is quite different. If lesions of the adrenal gland are found by accident in examinations otherwise indicated, the question arises whether the process is malignant or benign. In this respect, all the traditional imaging methods, including CT, involve a considerable factor or uncertainity, especially if a malignant tumor is anamnestically known and the question of metastases arises. According to recent information, MR-imaging seems to be advantageous concerning this difficult differential diagnosis. (orig.)

  11. Surgical treatment of gallbladder polypoid lesions

    Pejić Miljko A.; Milić Dragan J.

    2003-01-01

    INTRODUCTION Polypoid lesions of the gallbladder can be divided into benign and malignant categories. Malignant polypoid lesions include carcinomas of the gallbladder, which is the fifth most common malignancy of the gastrointestinal tract and the most common malignancy of the biliary tract. Benign polypoid lesions of the gallbladder are divided into true tumors and pseudotumors. Pseudotumors account for most of polypoid lesions of the gallbladder, and include polyps, hyperplasia, and other m...

  12. Lytic clavicular lesions in fibromatosis colli

    Two patients with fibromatosis colli (congenital torticollis) presented with lytic lesions in the clavicle at the insertion of the fibrosed clavicular head of the sternocleidomastoid muscle. Biopsy of one lesion showed intraosseous fibrosis. These lesions are probably not uncommon but radiographs are rarely performed in uncomplicated cases. (orig.)

  13. Lytic clavicular lesions in fibromatosis colli

    Sartoris, D.J.; Parker, B.R.; Mochizuki, R.M.

    1983-06-01

    Two patients with fibromatosis colli (congenital torticollis) presented with lytic lesions in the clavicle at the insertion of the fibrosed clavicular head of the sternocleidomastoid muscle. Biopsy of one lesion showed intraosseous fibrosis. These lesions are probably not uncommon but radiographs are rarely performed in uncomplicated cases.

  14. CLASSIFYING NODULAR LESIONS OF ORAL CAVITY

    Sumit Bhateja

    2013-01-01

    Diagnosis of many lesions of the oral cavity is challenging to most cliniciansbecause of their uncommon prevalence. A number of cystic, osteodystrophic,microbial, tumor and tumor like lesions of the oral cavity are present withcharacteristic exophytic/raised surface; which makes their diagnosis and studysimpler. The present article is attempted at classifying the common nodular lesions ofthe oral cavity.

  15. Achromatic orbital angular momentum generator

    Bouchard, Frédéric; Mirhosseini, Mohammad; Karimi, Ebrahim; Boyd, Robert W

    2014-01-01

    We describe a novel approach for generating light beams that carry orbital angular momentum (OAM) by means of total internal reflection in an isotropic medium. A continuous space-varying cylindrically symmetric reflector, in the form of \\textit{two glued hollow axicons}, is used to introduce a nonuniform rotation of polarisation into a linearly polarised input beam. This device acts as a full spin-to-orbital angular momentum convertor. It functions by switching the helicity of the incoming beam's polarisation, and by conservation of total angular momentum thereby generates a well-defined value of OAM. Our device is broadband, since the phase shift due to total internal reflection is nearly independent of wavelength. We verify the broad-band behaviour by measuring the conversion efficiency of the device for three different wavelengths corresponding to the RGB colours, red, green and blue. An average conversion efficiency of $95\\%$ for these three different wavelengths is observed. %, which confirms its wavelen...

  16. Achromatic orbital angular momentum generator

    We describe a novel approach for generating light beams that carry orbital angular momentum (OAM) by means of total internal reflection in an isotropic medium. A continuous space-varying cylindrically symmetric reflector, in the form of two glued hollow axicons, is used to introduce a nonuniform rotation of polarization into a linearly polarized input beam. This device acts as a full spin-to-orbital angular momentum convertor. It functions by switching the helicity of the incoming beam's polarization, and by conservation of total angular momentum thereby generates a well-defined value of OAM. Our device is broadband, since the phase shift due to total internal reflection is nearly independent of wavelength. We verify the broad-band behaviour by measuring the conversion efficiency of the device for three different wavelengths corresponding to the RGB colours, red, green and blue. An average conversion efficiency of 95% for these three different wavelengths is observed. This device may find applications in imaging from micro- to astronomical systems where a white vortex beam is needed. (paper)

  17. Achromatic orbital angular momentum generator

    Bouchard, Frédéric; Mand, Harjaspreet; Mirhosseini, Mohammad; Karimi, Ebrahim; Boyd, Robert W

    2014-01-01

    We describe a novel approach for generating light beams that carry orbital angular momentum (OAM) by means of total internal reflection in an isotropic medium. A continuous space-varying cylindrically symmetric reflector, in the form of \\textit{two glued hollow axicons}, is used to introduce a nonuniform rotation of polarisation into a linearly polarised input beam. This device acts as a full spin-to-orbital angular momentum convertor. It functions by switching the helicity of the incoming be...

  18. Structure and mechanism for DNA lesion recognition

    Wei Yang

    2008-01-01

    A fundamental question in DNA repair is how a lesion is detected when embedded in millions to billions of normal base pairs. Extensive structural and functional studies reveal atomic details of DNA repair protein and nucleic acid interactions. This review summarizes seemingly diverse structural motifs used in lesion recognition and suggests a general mechanism to recognize DNA lesion by the poor base stacking. After initial recognition of this shared struc-tural feature of lesions, different DNA repair pathways use unique verification mechanisms to ensure correct lesion identification and removal.

  19. Theory of pairwise lesion interaction

    A comparison between repair time constants measured both at the molecular and cellular levels has shown that the DNA double strand break is the molecular change of key importance in the causation of cellular effects such as chromosome aberrations and cell inactivation. Cell fusion experiments provided the evidence that it needs the pairwise interaction between two double strand breaks - or more exactly between the two ''repair sites'' arising from them in the course of enzymatic repair - to provide the faulty chromatin crosslink which leads to cytogenetic and cytolethal effects. These modern experiments have confirmed the classical assumption of pairwise lesion interaction (PLI) on which the models of Lea and Neary were based. It seems worthwhile to continue and complete the mathematical treatment of their proposed mechanism in order to show in quantitative terms that the well-known fractionation, protraction and linear energy transfer (LET) irradiation effects are consequences of or can at least be partly attributed to PLI. Arithmetic treatment of PLI - a second order reaction - has also the advantage of providing a prerequisite for further investigations into the stages of development of misrepair products such as chromatin crosslinks. It has been possible to formulate a completely arithmetic theory of PLI by consequently applying three biophysically permitted approximations - pure first order lesion repair kinetics, dose-independent repair time constants and low yield of the ionization/lesion conversion. The mathematical approach will be summarized here, including several formulae not elaborated at the time of previous publications. We will also study an application which sheds light on the chain of events involved in PLI. (author)

  20. Pancreatic Lesion: Malignancy or Abscess?

    Shulik, Oleg; Cavanagh, Yana; Grossman, Matthew

    2016-01-01

    BACKGROUND Pancreatic abscesses are rare. They may be seen in patients with pancreatic inflammation or pancreatitis. Patients with pancreatic abscesses may have abdominal pain, fever, chills, and nausea/vomiting or an inability to eat. Presentation with alternate symptomatology is extremely unusual. CASE REPORT A 67-year-old Asian male presented with painless, afebrile obstructive jaundice and a CA 19-9 of 1732 IU. He was found to have a 3.1×2.4 cm low-density lesion in the head of the pancreas and the right lobe of the liver, suggesting malignancy. Surgical management was considered, however additional diagnostic workup, including an endoscopic retrograde cholangiopancreatography (ERCP), was performed to complete staging of the presumed mass. A smooth, 3-cm-long, tapering stricture was found it the common bile duct. It was stented from the common hepatic duct to the duodenum. Subsequent endoscopic ultrasound (EUS) evaluation of the pancreatic head lesion revealed a drainable fluid collection that was aspirated and found to contain pyogenic material on pathology. The patient's symptoms resolved, and he was subsequently managed conservatively. A repeat ERCP confirmed complete resolution of the previously visualized cystic lesion. Interestingly, laboratory values showed concomitant normalization of CA 19-9 to 40 IU. CONCLUSIONS EUS-guided biopsy is not widely regarded as a required step before surgery, in the management of patients with pancreatic masses. It is generally reserved for determination of resectability or staging, and only utilized when clinically indicated. However, this practice may be associated with an inherently significant risk of misdiagnosis and subsequent unnecessary surgery, as illustrated by this case. Malignancy was initially suspected in our patient and surgical resection was recommended. Endoscopic measures were only pursued to complete staging. We propose that EUS-guided biopsy may be a crucial diagnostic step in the management algorithm

  1. Self-inflicted skin lesions

    Ring, Hans Christian; Smith, Matthias Nybro; Jemec, Gregor B E

    2014-01-01

    The current literature on the management of self-inflicted skin lesions points to an overall paucity of treatments with a high level of evidence (randomized controlled trials, controlled trials, or meta-analyses). In order to improve the communication between dermatologists and mental health...... professionals, the European Society for Dermatology and Psychiatry (ESDaP) recently proposed a classification of psychodermatological terms in order to establish a coherent use of terms across the medical fields involved. We reviewed current and previous psychodermatological diagnoses in order to clarify how...

  2. STUDY OF OVARIAN LESIONS IN CHILDREN

    Nagarjuna

    2015-11-01

    Full Text Available : AIM: To study ovarian lesions in paediatric patients. MATERIALS AND METHODS: All cases of ovarian lesions presenting to Niloufer Hospital during the study period spanning 7 years were included in the study. All cases were clinically examined and evaluated with serum markers like α-fetoprotein and β-HCG, ultrasonography of abdomen and pelvis and contrast enhanced computed tomography of abdomen and pelvis. The cases were managed either conservatively or surgically depending on the diagnosis. RESULTS: A total of 36 cases of ovarian lesions presented to Niloufer Hospital during the study period. The age of the patients ranged from newborn to 14 years. The most common presenting symptom was an abdominal or pelvic mass. The most common ultrasound character of the non-neoplastic ovarian lesion was cystic whereas that of a neoplastic ovarian lesion was complex or mixed. Non neoplastic lesions were present in 22 patients. Neoplastic lesions were seen in 14 patients. CONCLUSION: Physiological or functional ovarian cysts are the commonest ovarian lesions seen in the paediatric age group. Ultrasonogram is accurate and very reliable in distinguishing neoplastic from non-neoplastic and malignant from benign ovarian lesions. Non-neoplastic lesions can be managed conservatively in about 40% of cases. Neoplastic lesions in children require a less radical approach in order to preserve ovarian function.

  3. Dieulafoy's lesion of duodenum: a case report

    Wagholikar Gajanan D

    2003-01-01

    Full Text Available Abstract Background Dieulafoy's lesion is an uncommon but important cause of recurrent upper gastrointestinal bleeding. Extragastric location of Dieulafoy's lesion is rare. We report two cases of Dieulafoy's lesion of the duodenum and discuss the management of this extremely uncommon entity. Case presentation Two cases of massive upper gastro-intestinal bleeding in young adults due to Dieulafoy's lesion of the duodenum are reported. Endoscopic diagnosis was possible in both cases. Hemostasis was achieved successfully by endoscopic adrenaline injection. The endoscopic appearance, pitfalls in the diagnosis and management of this rare lesion are discussed. Conclusions Endoscopic diagnosis of extragastric Dieulafoy's lesion can be difficult because of the small size and obscure location of the lesion. Increased awareness and careful and early endoscopic evaluation following the bleeding episode are the key to accurate diagnosis. Adrenaline injection is one of the important endoscopic modalities for control of bleeding.

  4. Cutaneous lesions in new born

    Sachdeva Meenakshi

    2002-11-01

    Full Text Available Five hundred unselected newborn babies delivered in the Department of Obstetrics and Gynaecology, Unit II of SGBT Hospital attached to Government Medical College, Amritsar during April 2000 to October 2000 were examined for cutaneous lesions daily for the first five days after birth. Different cutaneous lesions were seen in 474(94. 8% newborns. The physiological skin changes observed in order of frequency were Epstein pearls in 305(61%, Mongolian spot in 301(60. 2%, superficial cutaneous desquamation in 200(40%, icterus in 128(25. 6%, milia in 119(23. 8%, sebaceous gland hyperplasia in 107 (21. 4%, occipital alopecia in 94(18. 8%, lanugo in 72(14. 4%, peripheral cyanosis in 47(9. 4%, breast hypertrophy in 29(5. 8% and miniature puberty in 28(5. 6% newborns. Of the transient non-infective skin diseases, erythema toxicum neonatorum was observed most commonly in 105(21 %, followed by miliaria rubra in 103(20. 6% and acne neonatorum in 27(5. 4% newborns. The naevi and other developmental defects in the descending order were salmon patch in 69(13. 8%, congenital melanocytic noevi in 10(2%, accessory tragi in 3(0.6%, spina bifida in 2(0.4%, hydrocephalus in 1(0.2% and poliosis in 1(0.2% newborns. Cradle cap was the only dermatitis observed in 50(10% newborns. One (0.2% case each of Harlequin ichthyosis and labial cyst was seen.

  5. Benign Lesions of The Vocal Fold

    Ozgur Surmelioglu

    2013-02-01

    Full Text Available Benign lesions of vocal folds are common disorders. Fifty percent of patients who have sound complaints are found to have these lesions after endoscopic and stroboscopic examinations. Benign vocal fold diseases are primarily caused by vibratory trauma. However they may also occur as a result of viral infections and congenital causes. These lesions are often presented with the complaints of dysphonia. [Archives Medical Review Journal 2013; 22(1.000: 86-95

  6. Radiologic aspects of the Galeazzi lesion

    In lesions of the forearm that included a fracture of the distal two thirds of the radial shaft, a concomitant disruption of the distal radio-ulnar joint was found in 20 out of 38 cases. In 15 cases a typical Galeazzi lesion was present. Dislocation of the distal radio-ulnar joint frequently goes unrecognized. The clinical significance of a lesion in the distal radio-ulnar joint is related to its prognostic value. (orig.)

  7. Management of Anal Squamous Intraepithelial Lesions

    Pineda, Carlos E.; Welton, Mark L.

    2009-01-01

    Anal squamous intraepithelial lesions include both low-grade squamous intraepithelial lesions (LSIL) and high-grade squamous intraepithelial lesions (HSIL) and are caused by chronic infection with the human papillomavirus (HPV). The disease is increasing in both incidence and prevalence, especially among patients with the following risk factors: homosexual men, acquired or iatrogenic immunosuppression, and presence of other HPV-related diseases. Although the natural history of the disease is ...

  8. Thermophysical lesions caused by HZE particles

    This paper deals with a type of damage caused by heavy particles that may occur in subcellular structures. These lesions are called thermophysical radiation injury and are similar to damage produced in solids by HZE particles. This chapter summarizes some of the experimental evidence for the presence of these lesions in certain mammalian tissues including the retina, brain, cornea, lens of mice and seeds of corn. Of all tissues examined, only the cornea exhibited a type of lesion which would fulfill the criteria of thermophysical lesions

  9. Gastrointestinal Polypoid Lesions: The Albanian Reality

    Gentiana Cekodhima

    2015-12-01

    Full Text Available Background: Gastrointestinal polypoid lesions are a well-known cause of possible future malignant lesions. Screening for these lesions, especially for colon polyps, has reduced morbidity and mortality from malignant tumors. To our best knowledge, no screening program on gastrointestinal polypoid lesions exists in Albania and no former study has been performed to check the distribution of these lesions. Therefore, our aim was to study the distribution of gastrointestinal polypoid lesions in a symptomatic outpatient population. Methods: This study included five hundred seventy five consecutive patients referred to perform an endoscopic examination, regardless of their specific complains and of their possible diagnosis, to one of the two Endoscopy Centers in Tirana in the period between January 1st 2008 and December 31st 2013. At least one polyp was resected and histologically examined in all included patients. Results: A total of 575 patients, of which 345 males (60.0%, aged 51.9 years (standard deviation 16.97 years, were examined and their data inserted in the statistical analysis. In total, 88 cases were identified with malignant pathologies of which 50 cases (56.8% were males. No case of malignancy was diagnosed among the nine esophageal specimens, but among the specimens resected from the stomach, small intestine and large intestine, were respectively diagnosed 21 (20.0%, 9 (40.9% and 58 (13.2% malignant lesions. Patients with malignant lesions were older (57.4 ± 16.8 years old in contrast to those with benign lesions (50.5 ± 17.0 years old (p = 0.004. Conclusion: Our study is the first one to offer figures on the polypoid lesions distribution and characteristics in the Albanian population. Large intestine is the main site where such lesions occur, but anyhow the small intestine presented a larger proportion of malignancy.

  10. Localization of lesions in aphasia, (2)

    The relationship between the focus and the extent of the lesions and the various symptoms was investigated. 1. Broca aphasics: More than 80% of the group with obvious anarthric components had lesions of the third frontal gyrus involving Broca's area and the lower part of the precental gyrus as well as opercular and insular regions. The size of the lesions of this group was significantly larger than that of the group without marked anarthric components, and the latter was proved to have little localizing value. 2. Wernicke aphasics: The group with poor reading comprehension had cortical and/or subcortical lesions, involving posterior parts of both superior and middle temporal gyri as well as the supramarginal gyrus. On the other hand, lesions of the group with poor auditory comprehension were more anteriorly located and localized in the deep structures. Lesions of the group with poor Token test scores were large and scattered more anteriorly and/or posteriorly compared with those of the group with good Token test scores. 3. Amnestic aphaiscs: The group with poor naming scores had somewhat larger lesions than the group with good naming scores, and the lesions were scattered about the left hemisphere. The finding has proved that both groups had little localizing value. 4. Conduction aphasics: Lesions of the non-fluent type were significantly larger than those of the fluent type and distributed more anteriorly. However, highly involved lesions were located in the supramarginal gyrus and posterior parts of superior and/or middle temporal gyri. 5. Global aphasics: Lesions of the group with good articulation and prosody were observed to distribute more posteriorly in comparison with those of the other global aphasics. (J.P.N.)

  11. Simulating the mammographic appearance of circumscribed lesions

    Optimization performance of digital image post-processing techniques in mammography requires controlled conditions of data sets permitting quantitative representation of image characteristics of pathological findings. Digital test objects, although objective and quantitative, do not mimic mammographic appearance and clinical data sets do not provide adequate sets of values of the various pathological finding characteristics. This can be overcome by digital simulation of pathological findings and superimposition on mammographic images. A simple method for simulation of mammographic appearance of radiopaque and/or radiolucent circumscribed lesions is presented. Circumscribed lesions are simulated using grey-level transformation functions which shift and compress the range of the initial pixel grey-level values in a region of interest (ROI) of a digitized mammographic image, according to grey-level analysis in 200 ROIs of real circumscribed lesions from digitized mammographic images. Simulation addresses lesion image characteristics, such as elliptical shape, orientation, halo sign for radiopaque lesions and capsule for radiolucent lesions, and is implemented in a user-driven PC-based interactive application. The appearance of the lesions is evaluated by six radiologists on a sample of 60 real and 60 simulated radiopaque lesions with the use of receiver operating characteristic (ROC) analysis. The area under the ROC curve, pooling the responses of the observers, was 0.55±0.03 indicating no statistically significant difference between real and simulated lesions (p>0.05). The method adequately simulates the mammographic appearance of circumscribed lesions and could be used to generate circumscribed lesion data sets for performance evaluation of image processing techniques, as well as education purposes. (orig.)

  12. Lesiones del ligamento cruzado anterior

    Alejandro Álvarez López

    2015-01-01

    Full Text Available Fundamento: el ligamento cruzado anterior desempeña un papel muy importante en la estabili-dad de la rodilla. La incidencia de esta afección es alta en pacientes que practican deportes de contacto y de no ser tratados de forma adecuada, los resultados son desfavorables. Objetivo: profundizar en los factores necesarios para el tratamiento adecuado de enfermos con esta lesión y evitar las complicaciones. Método: se realizó una revisión bibliográfica de un total de 300 artículos publicados en Pubmed, Hinari y Medline mediante el localizador de información Endnote, de ellos se utilizaron 52 citas selecciona-das para realizar la revisión, 48 de ellas de los últimos cinco años donde se incluyeron seis libros. Desarrollo: se discuten los aspectos relacionados con el diagnóstico clínico e imaginológico. Se aborda la clasificación de esta lesión en cuanto a varios aspectos como: tiempo, lesión de ligamentos u ósea, aislada o combinada y parcial o total. Se mencionan los parámetros para obtener resultados satisfac-torios al considerar factores como la edad del enfermo, lesiones asociadas y tiempo de la lesión. Se relacio-nan los requisitos para la selección del implante y se mostró las ventajas y desventajas de cada tipo de in-jerto. Las complicaciones de esta cirugía están relacionadas con la técnica quirúrgica y médicas. Conclusiones: las lesiones del ligamento son entidades traumáticas que afectan por lo general a pacientes jóvenes. Para lograr un resultado satisfactorio en el tratamiento es necesario el conocimiento de su anatomía, clasificación, tipo de injerto a emplear según sus ventajas y desventajas.

  13. Transarterial chemoembolization of liver lesions

    Full text: TACE is an image-guided, non-surgical procedure that is used to treat malignant lesions in the liver (mostly hepatocellular carcinoma). the procedure uses a catheter to deliver both chemotherapy medication and embolization materials into the blood vessels that lead to the tumor. This allows doctors to treat tumors that are not accessible using conventional surgery or radiation treatments. TACE derives its beneficial effect by two primary mechanisms. Most tumors within the liver are supplied by the proper hepatic artery, so arterial embolization preferentially interrupts the tumor’s blood supply and stalls growth until neovascularization. Secondly, focused administration of chemotherapy allows for delivery of a higher dose to the tissue while simultaneously reducing systemic exposure, which is typically the dose limiting factor. this effect is potentiated by the fact that the chemotherapeutic drug is not washed out from the tumor vascular bed by blood flow after embolization. Effectively, this results in a higher concentration of drug to be in contact with the tumor for a longer period of time. We are presenting our experience with TACE

  14. Cerebral CT of ischaemic lesions

    Aulich, A.

    1981-11-25

    The diagnosis of stroke must first be established by clinical examination. CT has proved useful for confirmation of the diagnosis and provides a global intracranial picture of morphological changes in cerebral vascular diseases. A hemorrhage can be recognized with certainty at the first CT examination as the cause of the stroke, but in the detection of a lesion due to ischemia an important role is played by the correct choice of the time of examination, and in some cases also of the check-up with contrast medium. The differential diagnosis between infarct in the acute stage and encephalitis or gliomas of low-grade malignity can be difficult. A decision can often only be made after a series of examinations. Postmalacial conditions are often difficult to differentiate from defects due to other causes, such as hemorrhage, head injury, postoperative states and after encephalitis. A knowledge of the anamnesis and the clinical findings is indispensable for CT evaluation. In assessing the prognosis before vascular surgery on the extracranial brain-supplying vessels the performance of a CT examination should be advised. A warning is given against the use of CT as a screening method.

  15. [Mandibular lesions in multiple myeloma].

    Scutellari, P N; Orzincolo, C

    1992-03-01

    A review was made of 237 cases of multiple myeloma seen at the Institute of Radiology and Hematology of the Ferrara University from 1984 through 1990. The results showed skeletal involvement of the mandible to be present in 25 patients (10.54%). The diagnosis of multiple myeloma was based on the following criteria: 1) increased number of abnormal, atypical or immature plasma cells in the bone marrow; 2) the presence of a monoclonal protein in the serum or urine; 3) bone lesions consistent with those of myeloma. Symptoms include pain and swelling of the oral cavity, tooth mobility and loss, numbness along the inferior dental nerve, and paresthesia of the lower lip. The typical radiographic appearance is a well-defined "punched-out" lytic defect, solitary or multiple; sometimes, the defect enlarges and appears "bubbly" or septated. Permeative lytic areas, with blurred outlines, are a rare pattern, which is radiologically indistinguishable from skeletal metastases. The involvement of the oral cavity and jaw in multiple myeloma has been often reported in literature: nevertheless, if radiographs of the jaws had been systematically taken in all the cases, its incidence would probably have been much higher than previously suspected. PMID:1579669

  16. Imaging granulomatous lesions with optical coherence tomography

    Banzhaf, Christina; Jemec, Gregor B E

    2012-01-01

    To investigate and compare the presentation of granulomatous lesions in optical coherence tomography (OCT) images and compare this to previous studies of nonmelanoma skin tumors.......To investigate and compare the presentation of granulomatous lesions in optical coherence tomography (OCT) images and compare this to previous studies of nonmelanoma skin tumors....

  17. White Matter Lesion Progression in LADIS

    Schmidt, Reinhold; Berghold, Andrea; Jokinen, Hanna; Gouw, Alida A; van der Flier, Wiesje M; Barkhof, Frederik; Scheltens, Philip; Petrovic, Katja; Madureira, Sofia; Verdelho, Ana; Ferro, Jose M; Waldemar, Gunhild; Wallin, Anders; Wahlund, Lars-Olof; Poggesi, Anna; Pantoni, Leonardo; Inzitari, Domenico; Fazekas, Franz; Erkinjuntti, Timo

    2012-01-01

    BACKGROUND AND PURPOSE: White matter lesion (WML) progression has been advocated as a surrogate marker in intervention trials on cerebral small vessel disease. We assessed the rate of visually rated WML progression, studied correlations between lesion progression and cognition, and estimated samp...

  18. Cathepsin Protease Inhibition Reduces Endometriosis Lesion Establishment.

    Porter, Kristi M; Wieser, Friedrich A; Wilder, Catera L; Sidell, Neil; Platt, Manu O

    2016-05-01

    Endometriosis is a gynecologic disease characterized by the ectopic presence of endometrial tissue on organs within the peritoneal cavity, causing debilitating abdominal pain and infertility. Current treatments alleviate moderate pain symptoms associated with the disorder but exhibit limited ability to prevent new or recurring lesion establishment and growth. Retrograde menstruation has been implicated for introducing endometrial tissue into the peritoneal cavity, but molecular mechanisms underlying attachment and invasion are not fully understood. We hypothesize that cysteine cathepsins, a group of powerful extracellular matrix proteases, facilitate endometrial tissue invasion and endometriosis lesion establishment in the peritoneal wall and inhibiting this activity would decrease endometriosis lesion implantation. To test this, we used an immunocompetent endometriosis mouse model and found that endometriotic lesions exhibited a greater than 5-fold increase in active cathepsins compared to tissue from peritoneal wall or eutopic endometrium, with cathepsins L and K specifically implicated. Human endometriosis lesions also exhibited greater cathepsin activity than adjacent peritoneum tissue, supporting the mouse results. Finally, we tested the hypothesis that inhibiting cathepsin activity could block endometriosis lesion attachment and implantation in vivo. Intraperitoneal injection of the broad cysteine cathepsin inhibitor, E-64, significantly reduced the number of attached endometriosis lesions in our murine model compared to vehicle-treated controls demonstrating that cathepsin proteases contribute to endometriosis lesion establishment, and their inhibition may provide a novel, nonhormonal therapy for endometriosis. PMID:26482207

  19. Infiltrating/sealing proximal caries lesions

    Martignon, S; Ekstrand, K R; Gomez, J;

    2012-01-01

    significant differences in lesion progression between infiltration and placebo (P = 0.0012) and between sealing and placebo (P = 0.0269). The study showed that infiltration and sealing are significantly better than placebo treatment for controlling caries progression on proximal lesions. No significant...... difference was seen between infiltration and sealing (ClinicalTrials.gov number NCT01417832)....

  20. Pediatric multifocal liver lesions evaluated by MRI

    Majed Almotairi

    2015-01-01

    Full Text Available Objective: The purpose of this study is to present our experience with MRI evaluation of multifocal liver lesions in children and describe the MRI characteristics of these lesions. Patients and Methods: A retrospective review of consecutive MRI exams performed for the evaluation of multiple liver lesions between 1 January 2007 and 31 December 2012 was done to note the number of lesions, the size of the largest lesion, MR signal characteristics, and background liver. Final diagnosis was assigned to each case based on pathology in the available cases and a combination of clinical features, imaging features, and follow-up in the remaining cases. Results: A total of 48 children (22 boys, 26 girls; age between 3 months and 18 years with average age 10.58 years and median age 11 years were included in the study. Totally 51 lesion diagnoses were seen in 48 children that included 17 focal nodular hyperplasia (FNH, 8 hemangiomas, 7 metastases, 6 regenerative nodules, 3 adenomas, 3 abscesses, and one each of angiomyolipoma, epithelioid hemangioendothelioma, focal fatty infiltration, hepatocellular carcinoma, hepatic infarction, nodular regenerative hyperplasia, and hepatic cyst. Background liver was normal in 33, cirrhotic in 10, fatty in 3, and siderotic in 2 children. Most FNH, hemangiomas, and regenerative nodules showed characteristic MRI features, while metastases were variable in signal pattern. Conclusion: Many commonly seen multifocal liver lesions in children have characteristic MRI features. MRI can help to arrive at reasonable differential diagnoses for multifocal liver lesions in children and guide further investigation and management.

  1. Principal component analysis of psoriasis lesions images

    Maletti, Gabriela Mariel; Ersbøll, Bjarne Kjær

    2003-01-01

    A set of RGB images of psoriasis lesions is used. By visual examination of these images, there seem to be no common pattern that could be used to find and align the lesions within and between sessions. It is expected that the principal components of the original images could be useful during future...

  2. Cystic ovarian lesions in SSFP diffusion imaging

    MR assessments of ovarian cystic lesions are usually based on morphological features, signal intensities and enhancement with contrast media. This study was performed to evaluate the usefulness of the steady-state free precession (SSFP) diffusion imaging of cystic ovarian lesions for analyzing cystic contents. Sixty-one ovarian cystic lesions in 37 patients were examined. The diffusion-related coefficient (DRC) and the ratio of the relative apparent diffusion coefficient of the lesion to that of subcutaneous fat tissue (rADCL/rADCF) were calculated from SSFP diffusion images. The DRCs and the rADCL /rADCF ratios in endometrial cysts and in the fatty parts of dermoid cysts were significantly lower than in other cystic tumors. SSFP diffusion imaging can be included in clinical practice to analyze ovarian cystic lesions within a short scan time; the DRC and the rADCL /rADCF ratio are useful for evaluating cystic contents. (author)

  3. MRI examination on microcalcification lesions on mammography

    With a recent increase of patients who are pointed out microcalcification on mammography (MMG) but otherwise normal, we have increasingly difficulties in making diagnosis. In this paper we examined magnetic resonance imaging (MRI) findings and diagnosis of microcalcification lesions. Out of consecutive patients who visited our hospital for close exploration of calcification on MMG from July 2006 to March 2009, 124 patients who were performed MRI were enrolled in this study. The morphology and enhancement kinetics of their lesions visualized by MRI were classified with reference to the breast imaging reporting and data system (BIRADS)-MRI and were compared with outcomes of histological diagnoses. As a result, all lesions in which no abnormal enhancement was seen on MRI were benign. Malignant lesions accounted for about 80.0% in mass patterns, and about more than half in non-mass like enhancement. About 30% of the lesions were malignant in the Focus/Foci pattern which designates lesions with the size of less than 5 mm. MRI is capable of predicting whether the microcalcification lesion is malignant or benign in some degree in patients with positive findings, and we can omit Stereotactic Mammotome biopsy (ST-MTB) in those with negative findings. Accordingly MRI is considered to be an extremely useful modality. (author)

  4. Nora's lesion, a distinct radiological entity?

    To describe the radiological findings of ''Bizarre parosteal osteochondromatous proliferation''(BPOP) - otherwise known as Nora's lesion, to describe the natural evolution of BPOP and to assess radiologically if BPOP is indeed part of a spectrum of reactive lesions including florid reactive periostitis and turret exostosis. Four experienced musculoskeletal radiologists studied plain radiographs and other imaging documents of histologically-proven Nora's lesions, looking for soft-tissue changes, periosteal reaction/calcification and calcified/ossified pseudotumours, and compared those findings with findings on pathology reviewed by a peer group of pathologists. Twenty-four Nora's lesions originating from a series of 200 consecutive, histologically-verified bone (pseudo)tumours of the hand, seen by the ''Netherlands Committee on Bone Tumours'' for review and second opinion. Nora's lesions have a recognised presentation on radiographs without specific MR characteristics. Natural evolution could be assessed retrospectively in four cases. Recurrent lesions were seen in seven cases and are difficult to differentiate from primary Lesions. (orig.)

  5. Sport lesions caused by athletics practice

    José Ernandes Feitoza

    2008-06-01

    Full Text Available Being a highly physical demanding sports, athletics depends on efficient training to overcome all physical demands without lesions. The aim of the present study was to analyze the types of lesions and their causes. The sample was constituted by forty-three athletes, sixteen males and twenty-seven females, 23.2 years of average age. A questionnaire containing five open questions and five closed questions was used as an instrument to determine the major lesions caused by athletics practice. The results showed that 84% of the athletes had already had some kind of lesions: 77% of which occurred during training and 23% during contest. The most frequent lesions were distension, tendinitis, twisting, contraction and inflammation. Legs were the most affected parts: 85% for jumpers, 85% for runners and 60% for throwers. When the lesions occurred, 76% of the jumpers, 84% of the runners and 85% of the throwers had no other health problem, but 52.7% of the athletes were in a state of anxiety before the contest and 13.8% had difficulties in concentrating on the contest. As for treatment 55.5% went to see a physiotherapist, and 16.6% went to see the medical doctor and the physiotherapist. The consequences of the lesions for the athletes’ performance were the following: 75% missed important contest events and 70% missed training for several months while they recuperated from their lesions. The results led to the conclusion that the best means to prevent lesions is to use adequate sites and equipments, efficient and individualized training coached by qualified specialists.

  6. Acquired CNS lesions in fetal MRI

    Acquired central nervous system (CNS) lesions are often subtle; therefore, the prenatal diagnosis of these lesions is extremely important. The fetal ultrasound examination and magnetic resonance imaging (MRI) are two important imaging methods that give an insight into these types lesions. The method of choice during pregnancy is still fetal ultrasound; however, fetal MRI is important when there are certain pathologies, e.g. periventricular leukomalacia (PVL) or malformations of the vein of Galen. In this manner clinicians can plan further therapy after childbirth in advance (e.g. cerebral angiography or embolization). (orig.)

  7. Multiple sclerosis with caudate lesions on MRI.

    Hashiguchi, S; Ogasawara, N; Mine, H; Kawachi, Y

    2001-04-01

    A 31-year-old woman displayed sleepiness and impairment of recent memory. T2-weighted MRI revealed high signal intensity lesions in the bilateral basal ganglia, thalamus, and brainstem. Although remission was achieved with corticosteroid therapy, she again displayed memory dysfunction and emotional disturbance one year later, at which time MRI disclosed new lesions in the right caudate nucleus and left frontal white matter. Corticosteroid therapy lead to improvement, and she suffered no recurrence on maintenance steroid therapy. These findings suggest that caudate lesions do occur in multiple sclerosis, the manifestations of which can be abulia and memory dysfunction, as in the present case. PMID:11334400

  8. Tibial cortical lesions: A multimodality pictorial review

    Tyler, P.A., E-mail: philippa.tyler@rnoh.nhs.uk [Department of Radiology, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore HA7 4LP (United Kingdom); Mohaghegh, P., E-mail: pegah1000@gmail.com [Department of Radiology, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore HA7 4LP (United Kingdom); Foley, J., E-mail: jfoley1@nhs.net [Department of Radiology, Glasgow Royal Infirmary, 16 Alexandra Parade, Glasgow G31 2ES (United Kingdom); Isaac, A., E-mail: amandaisaac@doctors.org.uk [Department of Radiology, King' s College Hospital, Denmark Hill, London SE5 9RS (United Kingdom); Zavareh, A., E-mail: ali.zavareh@gmail.com [Department of Radiology, North Bristol NHS Trust, Frenchay, Bristol BS16 1LE (United Kingdom); Thorning, C., E-mail: cthorning@doctors.org.uk [Department of Radiology, East Surrey Hospital, Canada Avenue, Redhill, Surrey RH1 5RH (United Kingdom); Kirwadi, A., E-mail: anandkirwadi@gmail.com [Department of Radiology, Manchester Royal Infirmary, Oxford Road, Manchester M13 9WL (United Kingdom); Pressney, I., E-mail: ipressney@hotmail.com [Department of Radiology, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore HA7 4LP (United Kingdom); Amary, F., E-mail: fernanda.amary@rnoh.nhs.uk [Department of Histopathology, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore HA7 4LP (United Kingdom); Rajeswaran, G., E-mail: grajeswaran@gmail.com [Department of Radiology, Chelsea and Westminster Hospital, 369 Fulham Road, London SW10 9NH (United Kingdom)

    2015-01-15

    Highlights: • Multimodality imaging plays an important role in the investigation and diagnosis of shin pain. • We review the multimodality imaging findings of common cortically based tibial lesions. • We also describe the rarer pathologies of tibial cortical lesions. - Abstract: Shin pain is a common complaint, particularly in young and active patients, with a wide range of potential diagnoses and resulting implications. We review the natural history and multimodality imaging findings of the more common causes of cortically-based tibial lesions, as well as the rarer pathologies less frequently encountered in a general radiology department.

  9. Macromolecular lesions and cellular radiation chemistry

    Our studies of the interaction of densely ionizing particles with macromolecules in the living cell may be divided into four parts: characterization of lesions to cellular DNA in the unmodified Bragg ionization curve; characterization of lesions to cellular DNA in the spread Bragg curve as used in radiation therapy; elucidation of the cellular radiation chemistry characteristic of high vs. low LET radiation qualities; and the introduction of novel techniques designed to give a better understanding of the fundamental properties of induction of lesions and their repair potentials in high LET radiation

  10. Lesion Contrast Enhancement in Medical Ultrasound Imaging

    Stetson, Paul F.; Sommer, F.G.; Macovski, A.

    1997-01-01

    Methods for improving the contrast-to-noise ratio (CNR) of low-contrast lesions in medical ultrasound imaging are described. Differences in the frequency spectra and amplitude distributions of the lesion and its surroundings can be used to increase the CNR of the lesion relative to the background....... Automated graylevel mapping is used in combination with a contrast-weighted form of frequency-diversity speckle reduction. In clinical studies, the techniques have yielded mean CNR improvements of 3.2 dB above ordinary frequency-diversity imaging and 5.6 dB over sharper conventional images, with no post...

  11. Pulmonary lesions mimicking pericardial effusion on ultrasonography

    Two children with right middle lobe lesions mimicking pericardial effusion on ultrasonography are presented. They were admitted with fever and chest radiographs showed atelectasis or consolidation of the middle lobe of the right lung along the right heart border. A low-echogenic layer suggesting pericardial fluid was seen on ultrasonography, but with a spatial distribution closely corresponding to the lesions seen on the chest radiographs. If the possibility that a lung lesion adjacent to the heart can simulate pericardial fluid on ultrasonography is kept in mind, the correct diagnosis should not be difficult to make. (orig.)

  12. Tibial cortical lesions: A multimodality pictorial review

    Highlights: • Multimodality imaging plays an important role in the investigation and diagnosis of shin pain. • We review the multimodality imaging findings of common cortically based tibial lesions. • We also describe the rarer pathologies of tibial cortical lesions. - Abstract: Shin pain is a common complaint, particularly in young and active patients, with a wide range of potential diagnoses and resulting implications. We review the natural history and multimodality imaging findings of the more common causes of cortically-based tibial lesions, as well as the rarer pathologies less frequently encountered in a general radiology department

  13. Oncocytic lesions of the ophthalmic region

    Østergaard, Jens; Prause, Jan U; Heegaard, Steffen

    2011-01-01

    Purpose: This study aimed to make a nationwide clinicopathological study of oncocytic lesions in the ophthalmic region and to characterize their cytokeratin (CK) expression. Methods: All histologically diagnosed oncocytic lesions in the ophthalmic region registered in Denmark over a 25-year period...... expression. Basal-type oncocytic cells reacted with antibodies against CK 5/6, CK 7, CK 8, CK 13, CK 14, CK 17, CK 18 and CK 19, and suprabasal cells with CK 4, CK 7, CK 8, CK 18 and CK 19. Antibodies against CK 1+10 and CK 20 showed no reaction. Conclusions: Oncocytic lesions of the ophthalmic region most...

  14. Lesion Expansion in Experimental Demyelination Animal Models and Multiple Sclerosis Lesions.

    Große-Veldmann, René; Becker, Birte; Amor, Sandra; van der Valk, Paul; Beyer, Cordian; Kipp, Markus

    2016-09-01

    Gray matter pathology is an important aspect of multiple sclerosis (MS) pathogenesis and disease progression. In a recent study, we were able to demonstrate that the higher myelin content in the white matter parts of the brain is an important variable in the neuroinflammatory response during demyelinating events. Whether higher white matter myelination contributes to lesion development and progression is not known. Here, we compared lesion size of intra-cortical vs. white matter MS lesions. Furthermore, dynamics of lesion development was compared in the cuprizone and lysophosphatidylcholine models. We provide clear evidence that in the human brain, white matter lesions are significantly increased in size as compared to intra-cortical gray matter lesions. In addition, studies using the cuprizone mouse model revealed that the autonomous progression of white matter lesions is more severe compared to that in the gray matter. Focal demyelination revealed that the application of equal amounts of lysophosphatidylcholine results in more severe demyelination in the white compared to the gray matter. In summary, lesion progression is most intense in myelin-rich white matter regions, irrespective of the initial lesion trigger mechanism. A better understanding of myelin debris-triggered lesion expansion will pave the way for the development of new protective strategies in the future. PMID:26363796

  15. Keloidal granuloma faciale with extrafacial lesions

    Verma Rajesh

    2005-01-01

    Full Text Available Granuloma faciale (GF is a rare cutaneous disorder characterized by one to several soft, erythematous to livid papules, plaques or nodules, usually occurring on the face. Extrafacial lesions are uncommon. A 52-year-old lady with multiple asymptomatic, variously sized brownish-black colored, firm, sharply circumscribed plaques resembling keloids on both cheeks and extrafacial lesions on the right arm and the right breast is presented for its unusual keloidal appearance and typical histopathological findings. She failed to respond to oral dapsone 100 mg daily administered for 3 months. Local infiltration of triamcinolone combined with cryotherapy led to only partial flattening of the lesions. All the skin lesions were excised surgically followed by flap transfer grafting on both cheeks. The cosmetic outcome was highly satisfactory.

  16. Keloidal granuloma faciale with extrafacial lesions.

    Verma, Rajesh; Das, A L; Vaishampayan, S S; Vaidya, Sachin

    2005-01-01

    Granuloma faciale (GF) is a rare cutaneous disorder characterized by one to several soft, erythematous to livid papules, plaques or nodules, usually occurring on the face. Extrafacial lesions are uncommon. A 52-year-old lady with multiple asymptomatic, variously sized brownish-black colored, firm, sharply circumscribed plaques resembling keloids on both cheeks and extrafacial lesions on the right arm and the right breast is presented for its unusual keloidal appearance and typical histopathological findings. She failed to respond to oral dapsone 100 mg daily administered for 3 months. Local infiltration of triamcinolone combined with cryotherapy led to only partial flattening of the lesions. All the skin lesions were excised surgically followed by flap transfer grafting on both cheeks. The cosmetic outcome was highly satisfactory. PMID:16394461

  17. Arthroscopy in the diagnosis of meniscus lesions

    Taser, Omer

    2004-01-01

    Approaches and their specialities in diagnostic arthroscopy have been presented. The things which should be noticed in the inspection of the menisci during arthroscopy have been put formend and indirect signs of meniscus lesion and their importance have been emphasized.

  18. Approximate Lesion Localization in Dermoscopy Images

    Celebi, M Emre; Schaefer, Gerald; Stoecker, William V; 10.1111/j.1600-0846.2009.00357.x

    2010-01-01

    Background: Dermoscopy is one of the major imaging modalities used in the diagnosis of melanoma and other pigmented skin lesions. Due to the difficulty and subjectivity of human interpretation, automated analysis of dermoscopy images has become an important research area. Border detection is often the first step in this analysis. Methods: In this article, we present an approximate lesion localization method that serves as a preprocessing step for detecting borders in dermoscopy images. In this method, first the black frame around the image is removed using an iterative algorithm. The approximate location of the lesion is then determined using an ensemble of thresholding algorithms. Results: The method is tested on a set of 428 dermoscopy images. The localization error is quantified by a metric that uses dermatologist determined borders as the ground truth. Conclusion: The results demonstrate that the method presented here achieves both fast and accurate localization of lesions in dermoscopy images.

  19. FNAC ACCURACY IN DIAGNOSIS OF BREAST LESIONS

    Venugopal; Pratap; Nikshita

    2014-01-01

    BACKGROUND: Malignancy of breast imposes significant reduction in life span. The prognosis of breast cancer is primarily dependent on the extent of disease and also early diagnosis in important. FNAC is a widely accepted cytological technique in the early diagnosis of palpable breast lesions. There have been many studies of accuracy of FNAC, which has been shown to be high in many centres. AIMS: To compare cytological and histopathological diagnosis of breast lesions and to ...

  20. Laser Treatment of Pediatric Vascular Lesions

    Cole, Patrick D.; Sonabend, Michael L.; Levy, Moise L.

    2007-01-01

    Since its introduction in 1967, laser therapy has benefited patients and physicians alike. After the first clinical application by Goldman (Anderson RR, Parrish JA. Science 1983;220:524–527), laser therapy has become indispensable in the management of vascular birthmarks. In selecting a proper balance of wavelength, pulse duration, and energy density (fluence), the physician can mold laser energy to effectively manage lesions once considered untreatable. Now, the vast array of lesions amenabl...

  1. Focal lesions in the central nervous system

    This report reviews the animal and human studies currently in progress at LBL with heavy-ion beams to induce focal lesions in the central nervous system, and discusses the potential future prospects of fundamental and applied brain research with heavy-ion beams. Methods are being developed for producing discrete focal lesions in the central nervous system using the Bragg ionization peak to investigate nerve pathways and neuroendocrine responses, and for treating pathological disorders of the brain

  2. The enigma of reversible spinal lesions

    Shalendra Kumar Misser

    2010-03-01

    Full Text Available Abstract Focal reversible lesions of the splenium of the corpus callosum have been described in a number of clinical paradigms. Epilepsy and related conditions are the most commonly reported underlying clinical association. Sudden anti-epileptic therapy withdrawal or seizure activity may be presumed to be the predisposing cause, however an individual susceptibility must also be considered. Herein, we present the findings in two patients with similar, completely reversible splenial lesions.

  3. Keloidal granuloma faciale with extrafacial lesions

    Verma Rajesh; Das A; Vaishampayan S.; Vaidya Sachin

    2005-01-01

    Granuloma faciale (GF) is a rare cutaneous disorder characterized by one to several soft, erythematous to livid papules, plaques or nodules, usually occurring on the face. Extrafacial lesions are uncommon. A 52-year-old lady with multiple asymptomatic, variously sized brownish-black colored, firm, sharply circumscribed plaques resembling keloids on both cheeks and extrafacial lesions on the right arm and the right breast is presented for its unusual keloidal appearance and typical histopathol...

  4. Common Adult Skin and Soft Tissue Lesions.

    Trost, Jeffrey G; Applebaum, Danielle S; Orengo, Ida

    2016-08-01

    A strong foundational knowledge of dermatologic disease is crucial for a successful practice in plastic surgery. A plastic surgeon should be able to identify and appreciate common dermatologic diseases that may require medical and/or surgical evaluation and management. In this article, the authors describe epidermal/dermal, infectious, pigmented, and malignant cutaneous lesions that are commonly encountered in practice. Descriptions include the epidemiology, pathogenesis, clinical course, and management options for each type of lesion. PMID:27478418

  5. Fine Needle Aspiration Cytology of Parathyroid Lesions

    Heo, Ilyeong; Park, Sunhoo; Jung, Chang Won; Koh, Jae Soo; Lee, Seung-Sook; Seol, Hyesil; Choi, Hee Seung; Cho, Soo Youn

    2013-01-01

    Background There has been an increase in the use of fine needle aspiration cytology (FNAC) for the diagnosis of parathyroid lesions (PLs). Differentiation between a thyroid lesion and a PL is not easy because of their similar features. We reviewed parathyroid aspirates in our institution and aimed to uncover trends in diagnostic criteria. Methods We selected 25 parathyroid aspirates (from 6 men and 19 women) confirmed surgically or immunohistochemically from 2006 to 2011. Results Major archit...

  6. Bone marrow lesions: A systematic diagnostic approach

    Filippo Del Grande

    2014-01-01

    Full Text Available Bone marrow lesions on magnetic resonance (MR imaging are common and may be seen with various pathologies. The authors outline a systematic diagnostic approach with proposed categorization of various etiologies of bone marrow lesions. Utilization of typical imaging features on conventional MR imaging techniques and other problem-solving techniques, such as chemical shift imaging and diffusion-weighted imaging (DWI, to achieve accurate final diagnosis has been highlighted.

  7. STUDY OF OVARIAN LESIONS IN CHILDREN

    Nagarjuna; Srinivas,; Ramesh Reddy; Lavanya; Inugala

    2015-01-01

    : AIM: To study ovarian lesions in paediatric patients. MATERIALS AND METHODS: All cases of ovarian lesions presenting to Niloufer Hospital during the study period spanning 7 years were included in the study. All cases were clinically examined and evaluated with serum markers like α-fetoprotein and β-HCG, ultrasonography of abdomen and pelvis and contrast enhanced computed tomography of abdomen and pelvis. The cases were managed either conservatively or surgically depending on...

  8. Photoacoustic Characterization of Radiofrequency Ablation Lesions

    Bouchard, Richard; Dana, Nicholas; Di Biase, Luigi; Natale, Andrea; Emelianov, Stanislav

    2012-01-01

    Radiofrequency ablation (RFA) procedures are used to destroy abnormal electrical pathways in the heart that can cause cardiac arrhythmias. Current methods relying on fluoroscopy, echocardiography and electrical conduction mapping are unable to accurately assess ablation lesion size. In an effort to better visualize RFA lesions, photoacoustic (PA) and ultrasonic (US) imaging were utilized to obtain co-registered images of ablated porcine cardiac tissue. The left ventricular free wall of fresh ...

  9. Papillary lesions of the breast diagnosed using core needle biopsies

    TOKINIWA, HIDEAKI; Horiguchi, Jun; TAKATA, DAISUKE; Kikuchi, Mami; ROKUTANDA, NANA; NAGAOKA, RIN; Sato, Ayako; Odawara, Hiroki; TOZUKA, KATSUNORI; Oyama, Tetsunari; Takeyoshi, Izumi

    2011-01-01

    Papillary lesions of the breast include a broad spectrum of lesions, from benign papillomas to papillary carcinomas. It is difficult to determine whether a lesion is benign or malignant based on the fragmented material of a core needle biopsy (CNB). This study evaluated patients with papillary lesions examined using CNB. We retrospectively reviewed 31 papillary lesions diagnosed using CNB between 2004 and 2007. The clinical findings of benign and malignant papillary lesions were compared. The...

  10. Computerized lesion detection on breast ultrasound.

    Drukker, Karen; Giger, Maryellen L; Horsch, Karla; Kupinski, Matthew A; Vyborny, Carl J; Mendelson, Ellen B

    2002-07-01

    We investigated the use of a radial gradient index (RGI) filtering technique to automatically detect lesions on breast ultrasound. After initial RGI filtering, a sensitivity of 87% at 0.76 false-positive detections per image was obtained on a database of 400 patients (757 images). Next, lesion candidates were segmented from the background by maximizing an average radial gradient (ARD) index for regions grown from the detected points. At an overlap of 0.4 with a radiologist lesion outline, 75% of the lesions were correctly detected. Subsequently, round robin analysis was used to assess the quality of the classification of lesion candidates into actual lesions and false-positives by a Bayesian neural network. The round robin analysis yielded an Az value of 0.84, and an overall performance by case of 94% sensitivity at 0.48 false-positives per image. Use of computerized analysis of breast sonograms may ultimately facilitate the use of sonography in breast cancer screening programs. PMID:12148724

  11. Skin conditions: benign nodular skin lesions.

    Nguyen, Tam; Zuniga, Ramiro

    2013-04-01

    Benign subcutaneous lesions are a common reason that patients visit family physicians. Lipomas are the most common of these lesions; they most often occur on the trunk and proximal extremities. Recent data show that as many as half of the fat cells in lipomas are atypical. Ultrasound is used increasingly to confirm lipoma diagnosis, but deep lesions should be evaluated with magnetic resonance imaging study or computed tomography scan to exclude involvement of underlying structures and/or liposarcoma. Small lesions can sometimes be managed with serial injections of midpotency steroids. Larger lesions (larger than 5 cm), those compressing other structures, or those suspicious for malignancy should be excised using standard surgical excision or, when possible, the newer minimal-scar segmental extraction technique. Ganglion cysts are another common lesion, the presence of which often is confirmed with ultrasound if the diagnosis is not clinically apparent. Management includes splinting, aspiration, and/or injection of steroids, with or without hyaluronidase. Epidermal inclusion cysts, also called sebaceous cysts, typically are asymptomatic unless they become infected. Ultrasound can aid in diagnosis. The only definitive management is surgical excision with complete removal of the cyst wall or capsule, using minimal-scar segmental extraction or conventional surgical removal. PMID:23600336

  12. Texture feature based liver lesion classification

    Doron, Yeela; Mayer-Wolf, Nitzan; Diamant, Idit; Greenspan, Hayit

    2014-03-01

    Liver lesion classification is a difficult clinical task. Computerized analysis can support clinical workflow by enabling more objective and reproducible evaluation. In this paper, we evaluate the contribution of several types of texture features for a computer-aided diagnostic (CAD) system which automatically classifies liver lesions from CT images. Based on the assumption that liver lesions of various classes differ in their texture characteristics, a variety of texture features were examined as lesion descriptors. Although texture features are often used for this task, there is currently a lack of detailed research focusing on the comparison across different texture features, or their combinations, on a given dataset. In this work we investigated the performance of Gray Level Co-occurrence Matrix (GLCM), Local Binary Patterns (LBP), Gabor, gray level intensity values and Gabor-based LBP (GLBP), where the features are obtained from a given lesion`s region of interest (ROI). For the classification module, SVM and KNN classifiers were examined. Using a single type of texture feature, best result of 91% accuracy, was obtained with Gabor filtering and SVM classification. Combination of Gabor, LBP and Intensity features improved the results to a final accuracy of 97%.

  13. Bizarre Parosteal Osteochondromatous Proliferation (Nora’s Lesion) of the Mandible. A Rare Bony Lesion

    Dashti, H. M.; Reith, J. D.; Schlott, B. J.; Lewis, E L; Cohen, D M; Bhattacharyya, I.

    2011-01-01

    Bizarre parosteal osteochondromatous proliferation (BPOP) also eponymically called “Nora’s lesion”, is a rare benign reactive bone lesion first reported in 1983. BPOP occurs classically on the bones of the hands and feet and long bones. This lesion can easily be confused, both clinically and microscopically, with other benign and malignant lesions of bone, including osteochondroma, parosteal osteosarcoma, myositis ossificans and reactive periostitis. BPOP has been reported to have a high rate...

  14. Abfraction lesions: etiology, diagnosis, and treatment options

    Nascimento, Marcelle M; Dilbone, Deborah A; Pereira, Patricia NR; Duarte, Wagner R; Geraldeli, Saulo; Delgado, Alex J

    2016-01-01

    Abfraction is a type of noncarious cervical lesion (NCCL) characterized by loss of tooth tissues with different clinical appearances. Evidence supports that abfraction lesions, as any NCCLs, have a multifactorial etiology. Particularly, the cervical wear of abfraction can occur as a result of normal and abnormal tooth function and may also be accompanied by pathological wear, such as abrasion and erosion. The interaction between chemical, biological, and behavioral factors is critical and helps to explain why some individuals exhibit more than one type of cervical wear mechanism than others. In an era of personalized dentistry, patient risk factors for NCCLs must be identified and addressed before any treatment is performed. Marked variations exist in dental practice concerning the diagnosis and management of these lesions. The lack of understanding about the prognosis of these lesions with or without intervention may be a major contributor to variations in dentists’ management decisions. This review focuses on the current knowledge and available treatment strategies for abfraction lesions. By recognizing that progressive changes in the cervical area of the tooth are part of a physiologically dynamic process that occurs with aging, premature and unnecessary intervention can be avoided. In cases of asymptomatic teeth, where tooth vitality and function are not compromised, abfraction lesions should be monitored for at least 6 months before any invasive procedure is planned. In cases of abfraction associated with gingival recession, a combined restorative-surgical approach may be performed. Restorative intervention and occlusal adjustment are not indicated as treatment options to prevent further tooth loss or progression of abfraction. The clinical decision to restore abfraction lesions may be based on the need to replace form and function or to relieve hypersensitivity of severely compromised teeth or for esthetic reasons. PMID:27217799

  15. Radiologic appearance of primary jaw lesions in children

    Gupta, Malini; Kaste, Sue C. [Department of Diagnostic Imaging, St. Jude Children' s Research Hospital, Memphis, TN (United States); Hopkins, Kenneth P. [Department of Surgery, Division of Dentistry, St. Jude Children' s Research Hospital, Memphis, TN (United States)

    2002-03-01

    Background: The jaw (an unusual site of primary tumors in children and adolescents) has lesions often found incidentally by dentists on routine panoramic radiographs or during examination of a child who has swelling or tooth pain. Objective: This pictorial seeks to familiarize pediatric radiologists with the radiographic appearance of a variety of primary jaw lesions. Materials and methods: We retrospectively searched institutional records for cases of primary jaw lesions in children and adolescents. Jaw lesions were characterized as: I, well-circumscribed radiolucent lesions; II, lesions with mixed or variable appearance; III, poorly circumscribed radiolucent lesions; and IV, radiopaque lesions. Results: Although most oral and maxillofacial lesions in children are benign, a broad spectrum of tumors was identified; lesions may occur in patients with unrelated prior malignancy. Conclusion: Because radiologic studies may identify jaw lesions and direct further care, familiarity with the appearance of these entities is prudent. (orig.)

  16. Radiologic appearance of primary jaw lesions in children

    Background: The jaw (an unusual site of primary tumors in children and adolescents) has lesions often found incidentally by dentists on routine panoramic radiographs or during examination of a child who has swelling or tooth pain. Objective: This pictorial seeks to familiarize pediatric radiologists with the radiographic appearance of a variety of primary jaw lesions. Materials and methods: We retrospectively searched institutional records for cases of primary jaw lesions in children and adolescents. Jaw lesions were characterized as: I, well-circumscribed radiolucent lesions; II, lesions with mixed or variable appearance; III, poorly circumscribed radiolucent lesions; and IV, radiopaque lesions. Results: Although most oral and maxillofacial lesions in children are benign, a broad spectrum of tumors was identified; lesions may occur in patients with unrelated prior malignancy. Conclusion: Because radiologic studies may identify jaw lesions and direct further care, familiarity with the appearance of these entities is prudent. (orig.)

  17. Venocentric lesions: an MRI marker of MS?

    Matthew P. Quinn

    2013-07-01

    Full Text Available From the earliest descriptions of MS, the venocentric characteristic of plaques was noted. Recently, numerous MRI studies have proposed this finding as a prospective biomarker for MS, which might aid in differentiating MS from other diseases with similar MRI findings. High field MRI studies have shown that penetrating veins can be detected in most MS lesions using T2* weighted or susceptibility weighted imaging. Future studies must address the feasibility of imaging such veins in a clinically practical context. The specificity of this biomarker has been studied only in a limited capacity. Results in microangiopathic lesions are conflicting, whereas asymptomatic white matter hyperintensities as well as lesions of NMO are less frequently venocentric compared to MS plaques. Prospective studies have shown that the presence of venocentric lesions at an early clinical presentation is highly predictive of future MS diagnosis. This is very promising, but work remains to be done to confirm or exclude lesions of common MS mimics, such as ADEM, as venocentric. A number of technical challenges must be addressed before the introduction of this technique as a complementary tool in current diagnostic procedures.

  18. Computer detection of stellate lesions in mammograms

    Kegelmeyer, W. Philip, Jr.

    1992-06-01

    The three primary signs for which radiologists search when screening mammograms for breast cancer are stellate lesions, microcalcifications, and circumscribed lesions. Stellate lesions are of particular importance, as they are almost always associated with a malignancy. Further, they are often indicated only by subtle architectural distortions and so are in general easier to miss than the other signs. We have developed a method for the automatic detection of stellate lesions in digitized mammograms, and have tested them on image data where the presence or absence of malignancies is known. We extract image features from the known images, use them to grow binary decision trees, and use those trees to label each pixel of new mammograms with its probability of being located on an abnormality. The primary feature for the detection of stellate lesions is ALOE, analysis of local oriented edges, which is derived from an analysis of the histogram of edge orientations in local windows. Other features, based on the Laws texture energy measures, have been developed to respond to normal tissue, and so improve the false alarm performance of the entire system.

  19. Evaluation of various hepatic lesions with PET

    When a liver lesion is found in a PET image, differential diagnosis and analysis of the lesion is very important. We tried to analyze hepatic lesions found in PET. 53 patients with focal liver lesions (13 patients with HCC, 8 patients with cholangiocarcinoma (CC), 20 patients with liver metastasis, 5 patients with hemangioma, 7 patients with liver abscess, including 1 patient with liver candidiasis) were examined. Definitely high FDG uptake pattern were observed in 54% (7/13) of HCC, 100% (8/8) of CC, 95% (19/20) of metastatic liver cancer and 100% (7/7) of liver abscess. Therefore, PET was partially useful in the diagnosis of HCC, but it was very useful in the diagnosis of CC or liver metastasis or liver abscess. The contrast between lesions and surrounding liver background was very conspicuous in PET images of CC or liver metastasis or liver abscess, which suggests that PET might be used for the follow up and assessment of treatment response of these diseases

  20. [Pigmented lesions of the oral cavity].

    Brocheriou, C; Kuffer, R; Verola, O

    1985-01-01

    Pigmented lesions of the oral cavity are of multiple origin. They can be subdivided as follows: non tumoral pigmentations, non melanin pigmented tumors or tumor-like lesions, benign melanin pigmented tumors and malignant melanomas. Among non tumoral pigmented lesions, some of them show melanin deposits: they can be associated with a systemic disease (Peutz Jeghers syndrome, Addison's disease) or have a medicamentous origin, or belong to a lichen migricans. Non tumoral and non melanin pigmentations are principally due to a heavy metal accumulation or an accidental tatoo arising after tooth treatment. Peripheral giant cell granuloma, so-called giant cell epulis is the major non pigmented non melanin pseudotumoral lesion; pigmentation is due to hemosiderin deposits. In the oral cavity nevi are principally of the intramucosal type. Blue nevus, the second type in frequency, is usually located on the hard palate. Primary malignant melanomas are rare in the oral cavity, but it is--because its very bad prognosis--the most important lesion. In order to improve the survival it is necessary to do the diagnosis as early as possible. PMID:3833244

  1. Evaluation of various hepatic lesions with PET

    Han, Chul Ju

    2000-12-01

    When a liver lesion is found in a PET image, differential diagnosis and analysis of the lesion is very important. We tried to analyze hepatic lesions found in PET. 53 patients with focal liver lesions (13 patients with HCC, 8 patients with cholangiocarcinoma (CC), 20 patients with liver metastasis, 5 patients with hemangioma, 7 patients with liver abscess, including 1 patient with liver candidiasis) were examined. Definitely high FDG uptake pattern were observed in 54% (7/13) of HCC, 100% (8/8) of CC, 95% (19/20) of metastatic liver cancer and 100% (7/7) of liver abscess. Therefore, PET was partially useful in the diagnosis of HCC, but it was very useful in the diagnosis of CC or liver metastasis or liver abscess. The contrast between lesions and surrounding liver background was very conspicuous in PET images of CC or liver metastasis or liver abscess, which suggests that PET might be used for the follow up and assessment of treatment response of these diseases.

  2. Petrous apex lesions outcome in 21 cases

    Hekmatara M

    1997-09-01

    Full Text Available Petrous apex lesions of temporal bone progress slowly. Most of the time not only destruct this area but also involve neighbouring element. The symptoms of the neighbouring neuro-vasculare involvement we can recognize these lesions. The most common symptoms of involvement of the petrous apex are: headache, conductive hearing loss or sensorineural type, paresthesia and anesthesia of the trigeminal nerve, paresia and paralysis of the facial nerve, abducent nerve. In retrospective study which has been in the ENT and HNS wards of Amiralam hospital, 148 patients have been operated due to temporal bone tumor; from these numbers, 21 (13.6% patients had petrous apex lesions of temporal bone. Eleven (52.9% patients of these 21 persons were men and the remaining 10 (47-6% were women. The average age of the patients was 37 years. The common pathology of these patients were glomus jugulare tumors, hemangioma, schwannoma, meningioma, congenital cholesteatoma, giant cell granuloma. The kind of operations that have been done on these patients were: infratemporal, translabyrinthine and middle fossa approaches. The conclusion of this study shows that petrous apex area is an occult site. The symptoms of this lesion are not characteristic, meticulous attention to the history and physical examination are very helpful to recognition of these lesions and it's extention.

  3. Producing Uniform Lesion Pattern in HIFU Ablation

    Zhou, Yufeng; Kargl, Steven G.; Hwang, Joo Ha

    2009-04-01

    High intensity focused ultrasound (HIFU) is emerging as a modality for treatment of solid tumors. The temperature at the focus can reach over 65° C denaturing cellular proteins resulting in coagulative necrosis. Typically, HIFU parameters are the same for each treated spot in most HIFU control systems. Because of thermal diffusion from nearby spots, the size of lesions will gradually become larger as the HIFU therapy progresses, which may cause insufficient treatment of initial spots, and over-treatment of later ones. It is found that the produced lesion pattern also depends on the scanning pathway. From the viewpoint of the physician creating uniform lesions and minimizing energy exposure are preferred in tumor ablation. An algorithm has been developed to adaptively determine the treatment parameters for every spot in a theoretical model in order to maintain similar lesion size throughout the HIFU therapy. In addition, the exposure energy needed using the traditional raster scanning is compared with those of two other scanning pathways, spiral scanning from the center to the outside and from the outside to the center. The theoretical prediction and proposed algorithm were further evaluated using transparent gel phantoms as a target. Digital images of the lesions were obtained, quantified, and then compared with each other. Altogether, dynamically changing treatment parameters can improve the efficacy and safety of HIFU ablation.

  4. Rare Infraglottic Lesions in Magnetic Resonance Imaging

    Primary pathological laryngeal lesions occur rarely in infraglottic space. Modern possibilities of diagnostic imaging of infraglottic space include computed tomography (CT) and magnetic resonance (MR). Diagnostic imaging was performed in potential lesions in this area: inflammatory process – cicatrical pemphigoid, benign neoplastic process – chondroma, malignant neoplastic – squamous cell carcinoma. The aim of the paper is to present clinical and radiographical characteristics of selected lesions located in infraglottic space in MRI examination. Three patients examined at the Department of Radiology and Diagnostic Imaging of University Hospital No. 1 in Lodz (SPZOZ USK nr 1) from 2010–2011 with a pathological mass in infraglottic space. Standard imaging protocol for MRI of the neck was used in all patients: field of 1.5 T, slice thickness 3 mm, the distance between the scans 10–20%, FOV – 3 mm, sequences: T1 (TR/TE 455/9, 7 ms, T2 (TR/TE 5300/67 ms), T1 + Gd-DTPA (contrast agent Gd-DTPA at 0.2 mmol/kg). 1. It is possible to determine characteristic signal pattern for rare lesions of the infraglottic space in MRI. 2. MRI is a valuable complementary modality for the diagnostics and differentiation of lesions in infraglottic space, the evaluation of their advancement and treatment planning

  5. Oral White Lesions: Presentation and Comparison of Oral Submucous Fibrosis with Other Lesions

    Objective: To compare oral submucous fibrosis with other white oral lesions for presentation and associated factors. Study Design: Cross-sectional study. Place and Duration of Study: The Departments of Oral Medicine and Oral and Maxillofacial Surgery, Dr. Ishrat-ul-Ibad Institute of Oral Health Sciences (DIKIOHS), Karachi, from May 2008 to May 2009. Methodology: Patients presenting with oral white lesions were selected by consecutive non-purposive sampling and clinico-demographic data was collected. For patients with oral submucous fibrosis (OSF), additional information like duration of habits, maximal incisal opening (MIO), presence of any other associated lesion were noted. OSF was compared with other white lesions for any association between characteristic of subjects. Chi-square and independent t-tests for determining the statistical significance at p < 0.05. Results: OSF was present in 59.6% (n = 106) of the 178 patients; other white lesions were 40.4% (n = 72). The mean age of patients with OSF was 34 +- 12.7 years and 45.81 +- 16.2 years in patients with other white lesions, (p < 0.0001). Items containing areca nut were consumed more by patients with OSF, with a significant (p < 0.0001) compared to patients with other white lesions. Conclusion: OSF was the predominant white lesion in patients examined at DIKIOHS. Areca nut was found to be chewed more by patients with OSF and still longer by patients with SCC. (author)

  6. Lesions in nerves and plexus after radiotherapy

    Apart from the typical, radiation-induced changes in the skin, common secondary findings were oedemas, radiation-induced ulceration, fibroses of the mediastinum and lungs, pleura adhesions, and osteoradionecroses. In one patient with radiogenic paresis of the plexus brachialis, irradiation of the spinal cord because of epidural metastases of a mammary carcinoma resulted in radiation myelopathy which was verified by laminectomy. Observations of radiogenic lesions of the plexus brachialis show that the usual site of the lesion in the vasomotoric nerve bundle is the axilla. The lesion is assumed to be caused mainly by an overlapping of the axillary, infraclavicular and supraclavicular fields of irradiation which results in a dose peak in the axilla. (orig./AJ) 891 AJ/orig.- 892 MKO

  7. Morgellons Disease Presenting As an Eyelid Lesion.

    Sandhu, Rasanamar K; Steele, Eric A

    2016-01-01

    Morgellons disease is characterized by complaints of uncomfortable skin sensations and fibers emanating from nonhealing skin lesions. Morgellons disease is well-known in the dermatology and psychiatry literature, where it is typically considered a subtype of delusional parasitosis, but it has not yet been described in the ophthalmology literature. A patient with self-reported Morgellons disease is presented, who was referred for evaluation of left lower eyelid ectropion. She reported that her skin was infested with fibers that were "trying to get down into the eyelid." On examination, she had ectropion of the left lower eyelid, broken cilia, and an ulcerated left upper eyelid lesion concerning for carcinoma. Biopsy of the lesion was consistent with excoriation. Treatment of her ectropion was deferred out of concern for wound dehiscence, given the patient's aggressive excoriation behavior. This case is presented to make the ophthalmologist aware of this disorder and to highlight the appropriate clinical management. PMID:25192328

  8. Blue light hazards for ocular lesions

    The blue light range (400-500 nm) of visible radiation stimulates specifically cones and rods of the retina. The carried energy by these wavelengths is absorbed and transferred to specific pigments. Their energy is sufficient to produce free radicals and singlet form of oxygen. Intense sources, rich in blue light radiation, may induce, in the retina, photo-toxic lesions either limited or short-lived or photothermal lesions more or less definitive. Repeated photo-toxic lesions should be the root for the age-related maculo-pathy (A.R.M.) also called late macular degeneration (A.M.D.). As a consequence, the attention should be drawn on the potential risk linked to modern lighting as 'daylight' lamp, compact fluorescent lamps, energy saving (C.F.L.) and light-emitting diodes (L.E.D.) for which a specific vigilance should be enforced. (author)

  9. Endoscopic management of orbital apex lesions.

    Sethi, D S; Lau, D P

    1997-01-01

    Lesions of the orbital apex often present a diagnostic dilemma. Clinical assessment and imaging studies are helpful but a tissue biopsy is often required. The morbidity associated with transcranial approaches to the orbital apex may outweigh the benefits of obtaining a biopsy by these routes. Fine needle aspiration cytology of orbital apex lesions can be performed but there are disadvantages with this method. We describe a transnasal endoscopic technique to biopsy the orbital apex. The technique was used successfully to obtain a tissue diagnosis in six patients with orbital apex lesions. This enabled commencement of definitive treatment. There were no significant complications. The transnasal approach to the orbital apex using the endoscopes is reliable. Endoscopes provide excellent illumination, magnification, and a panoramic view of the operative field. PMID:9438058

  10. Imaging of Retrosternal Space Lesions – A Pictorial Review

    Chandrashekhara, S.H.; Rahul, Kumar; Handa, Nayha; Panda, Ananya

    2016-01-01

    Summary The retrosternal region (RSS) can be involved by diverse lesions. The RSS is the region behind the sternum and anterior to the ascending aorta. It normally is less than 3 cm deep. Chest X-ray is usually the first imaging modality to raise a suspicion of RSS pathology; however computed tomography is the mainstay to delineate and characterize lesions in this location. Lesions in this location include thyroid, thymic and lymph node lesions; germ cell tumors and vascular lesions. Lesions arising from the sternum, lungs as well as the pleura can also involve this space. The pictorial review depicts the diverse spectrum of lesions in this location. PMID:27504144

  11. Imaging of Retrosternal Space Lesions - A Pictorial Review.

    Chandrashekhara, S H; Rahul, Kumar; Handa, Nayha; Panda, Ananya

    2016-01-01

    The retrosternal region (RSS) can be involved by diverse lesions. The RSS is the region behind the sternum and anterior to the ascending aorta. It normally is less than 3 cm deep. Chest X-ray is usually the first imaging modality to raise a suspicion of RSS pathology; however computed tomography is the mainstay to delineate and characterize lesions in this location. Lesions in this location include thyroid, thymic and lymph node lesions; germ cell tumors and vascular lesions. Lesions arising from the sternum, lungs as well as the pleura can also involve this space. The pictorial review depicts the diverse spectrum of lesions in this location. PMID:27504144

  12. CT diagnosis of cystic ovarian lesions

    CT was undertaken and CT numbers were measured in 47 patients with cystic ovarian lesions. CT features particularly for chocolate cyst revealed the uniform thickness of the whole cystic wall, findings suggesting adhesion to the surrounding organs, circular or oval shape, and higher CT numbers within the cyst than those in the other cystic ovarian lesions. However, because these features are not always observed in cases of chocolate cyst, one should not rely solely on CT findings in the diagnosis of chocolate cyst. (Namekawa, K.)

  13. Non-infectious inflammatory genital lesions.

    Andreassi, Lucio; Bilenchi, Roberta

    2014-01-01

    The genitalia may be the site of non-infectious inflammatory lesions that are generally manifested as balanoposthitis and vulvovaginitis. In men, these forms constitute 50% of all balanoposthitis forms, and in women, vulvovaginitis frequency is even higher. They consist of genital locations of general skin diseases, such as psoriasis, lichen planus, lichen sclerosus, and other clinical entities with their own physiognomy, such as Zoon's balanitis-vulvitis. Diagnosis of genital non-infectious inflammatory lesions is usually made on clinical criteria. A biopsy is only necessary for the identification of clinical conditions that may simulate inflammatory form but are actually premalignant processes. PMID:24559568

  14. MR findings of the spinal epidural lesions

    Kim, Dong Hun; Lee, Ho Kyu; Shin, Ji Hoon; Choi, Choong Gon; Suh, Dae Chul; Shin, Myung Jin; Rhim, Seung Chul [Ulsan Univ. College of Midicine, Seoul (Korea, Republic of); Park, Sung Tae [Dongguk Univ. College of Midicine, Kyungju (Korea, Republic of)

    2001-04-01

    The spinal canal takes the form of a series of cylinders designated by their relationship to the meninges and is divided by the dura mater into the epidural or extradural space and intradural space. The epidural space is composed of spinal ligaments, connective and areolar tissue, the epidural venous plexus, lymphatic channels and supporting elements, and various pathologic entities are found there. MR imaging can accurately depict the extent and characteristics of lesions, and in some cases specific diagnosis is possible. In this pictorial essay, we illustrate a variety of spinal epidural lesions and their MR findings.

  15. Treatment of calcified coronary artery lesions.

    Farag, Mohamed; Costopoulos, Charis; Gorog, Diana A; Prasad, Abhiram; Srinivasan, Manivannan

    2016-06-01

    Heavily calcified coronary plaques represent a complex lesion subset and a challenge to the interventional cardiologist, as they are often resistant to simple plaque modification with conventional balloon angioplasty. Inadequate plaque modification can lead to stent underdeployment, which itself predisposes to in-stent restenosis and stent thrombosis. Over the years, a number of mechanical devices ranging from modified angioplasty balloons to atherectomy devices have become available in order to tackle such lesions. Here we review these devices concentrating on the evidence behind their use. PMID:26924773

  16. Post-traumatic contrast enhancing brain lesion

    Kim, Dae Jung; Kim, Hyun Sook; Jeong, Min Sun; Kim, Deok Ryeong; Cho, Young Kwon; Choi, Yun Sun [Eulji Hospital, Eulji University College of Medicine, Seoul (Korea, Republic of)

    2014-10-15

    Only a few studies have been reported on the MR contrast enhancement and the apparent diffusion coefficient (ADC) findings of the post-traumatic lesion of the brain. We report a case of the venous ischemia in the left frontal lobe observed in the MRI obtained one day after the incidence of trauma. Considering the presented slight increase in the ADC, the vasogenic edema was thought to be the major mechanism of the venous ischemia and excitotoxic injury. In spite of a slight increase in the ADC, the hyperintensity in the diffusion weighted imaging and contrast-enhanced areas eventually changed into hemorrhagic lesions.

  17. Human papillomavirus in oral lesions Virus papiloma humano en lesiones orales

    Joaquín V. Gónzalez

    2007-08-01

    Full Text Available Growing evidence suggests a role for human papillomavirus (HPV in oral cancer; however its involvement is still controversial. This study evaluates the frequency of HPV DNA in a variety of oral lesions in patients from Argentina. A total of 77 oral tissue samples from 66 patients were selected (cases; the clinical-histopathological diagnoses corresponded to: 11 HPV- associated benign lesions, 8 non-HPV associated benign lesions, 33 premalignant lesions and 25 cancers. Sixty exfoliated cell samples from normal oral mucosa were used as controls. HPV detection and typing were performed by polymerase chain reaction (PCR using primers MY09, 11, combined with RFLP or alternatively PCR using primers GP5+, 6+ combined with dot blot hybridization. HPV was detected in 91.0% of HPV- associated benign lesions, 14.3% of non-HPV associated benign lesions, 51.5% of preneoplasias and 60.0% of cancers. No control sample tested HPV positive. In benign HPV- associated lesions, 30.0% of HPV positive samples harbored high-risk types, while in preneoplastic lesions the value rose to 59.9%. In cancer lesions, HPV detection in verrucous carcinoma was 88.9% and in squamous cell carcinoma 43.8%, with high-risk type rates of 75.5% and 85.6%, respectively. The high HPV frequency detected in preneoplastic and neoplastic lesions supports an HPV etiological role in at least a subset of oral cancers.Crecientes evidencias sugieren que el virus Papiloma humano (HPV tiene un rol en el cáncer oral; sin embargo su participación es todavía controvertida. Este estudio evalúa la frecuencia de ADN de HPV en una variedad de lesiones orales de pacientes de Argentina. Se seleccionaron 77 muestras de tejido oral de 66 pacientes (casos; el diagnóstico histo-patológico correspondió a: 11 lesiones benignas asociadas a HPV, 8 lesiones benignas no asociadas a HPV, 33 lesiones premalignas y 25 cánceres. Como controles se usaron 60 muestras de células exfoliadas de mucosa oral normal. La

  18. The wide spectrum of hyperechoic lesions of the breast

    Linda, A., E-mail: annalinda33@gmail.co [Institute of Diagnostic Radiology, University of Udine, Azienda Ospedaliero-Universitaria Santa Maria della Misericordia, Udine (Italy); Zuiani, C.; Lorenzon, M.; Furlan, A.; Londero, V. [Institute of Diagnostic Radiology, University of Udine, Azienda Ospedaliero-Universitaria Santa Maria della Misericordia, Udine (Italy); Machin, P. [Institute of Pathology, Ospedale De Gironcoli, Conegliano (Italy); Bazzocchi, M. [Institute of Diagnostic Radiology, University of Udine, Azienda Ospedaliero-Universitaria Santa Maria della Misericordia, Udine (Italy)

    2011-06-15

    Although breast lesions are commonly detected because of their hypoechogenicity, some lesions may present with hyperechogenicity due to their histological components. Hyperechogenicity has been shown to be highly predictive of benignity; however, hyperechoic lesions can occasionally be malignant. This article reviews hyperechoic lesions of the breast, describes the underlying histological causes associated with hyperechogenicity, and the sonographic features useful for the differential diagnosis between benign and malignant hyperechoic lesions.

  19. Benign Proliferative Breast Lesions and Risk of Cancer

    Serap Erel

    2010-01-01

    Benign breast lesions (BBL) includes a wide variety of histologic entities, which have been broadly classified into non-proliferative lesions, proliferative lesions without atypia, and hyperplasia with atypia. With the increased use of mammography, more benign lesions are being detected, and in order to estimate the risk of breast cancer for specific histologic categories is of great importance to guide clinical management. Women with proliferative lesions without atypia are at slightly incre...

  20. The comparison of excisionel biopsies between wire-guided and radioguided occult lesion localization in nonpalpable breast lesions

    Kağan Karabulut

    2011-01-01

    The development of breast imaging methodsincreased frequent of nonpalpable breast lesions.Consequently, diagnosis of early breast cancer increasedand breast cancer mortality decreased. Several techniqueswere described for excisional biopsy of nonpalpablebreast lesions. Wire guided localization is currentlythe most commonly used localization method for nonpalpablebreast lesions. ROLL is a possible alternative tothe commonly used wire guided localization of non palpablebreast lesions and ROLL i...

  1. Surgical treatment of gallbladder polypoid lesions

    Pejić Miljko A.

    2003-01-01

    Full Text Available INTRODUCTION Polypoid lesions of the gallbladder can be divided into benign and malignant categories. Malignant polypoid lesions include carcinomas of the gallbladder, which is the fifth most common malignancy of the gastrointestinal tract and the most common malignancy of the biliary tract. Benign polypoid lesions of the gallbladder are divided into true tumors and pseudotumors. Pseudotumors account for most of polypoid lesions of the gallbladder, and include polyps, hyperplasia, and other miscellaneous lesions. Adenomas are the most common benign neoplasms of the gallbladder. Cholesterol polyps are the most common pseudotumors of the gallbladder. The polyps can be single or multiple, usually less than 10 mm in size. They have no predilection for any particular gallbladder site, and usually are attached to the gallbladder wall by a delicate, narrow pedicle. No malignant potential has been identified for this type of pseudotumor. Adenomas are the most common benign neoplasms of the gallbladder. They have no predilection site in the gallbladder, and may also be associated with gallstones or cholecystitis. The premalignant nature of adenomas remains controversial. Ultrasonography (US has been demonstrated to be significantly better in detecting polypoid lesions of the gallbladder as compared with computed tomography and cholecystography. A mass fixed to the gallbladder wall of normal thickness, without shadowing, is seen in case of gallbladder polyp. Since gallbladder cancers usually present as polypoid lesions, differentiation between benign polypoid lesion and malignant lesion can be very difficult, even with high-resolution imaging techniques. PATIENTS AND METHODS Retrospectively we have analyzed 38 patients with ultrasonographicaly detected gallbladder polyps during the period from January 1995 to December 2000, who were treated at surgical department of Health Centre in Uzice and at Surgical clinic of Clinical Centre in Nis. We have analyzed

  2. Classification of breast lesions presenting as mass and non-mass lesions

    Gallego-Ortiz, Cristina; Martel, Anne L.

    2014-03-01

    We aim to develop a CAD system for robust and reliable di erential diagnosis of breast lesions, in particular non-mass lesions. A necessary prerequisite for the development of a successful CAD system is the selection of the best subset of lesion descriptors. But an important methodological concern is whether the selected features are in uenced by the model employed rather than by the underlying characteristic distribution of descriptors for positive and negative cases. Another interesting question is how a particular classi er exploits the relationships between descriptors to increase the accuracy of the classi cation. In this work we set to: (1) Characterize kinetic, morphological and textural features among mass and non-mass lesions; (2) Examine feature spaces and compare selection of subset of features based on similarity of feature importance across feature rankings; (3) Compare two classi er performances namely binary Support Vector Machines (SVM) and Random Forest (RF) for the task of di erentiating between positive and negative cases when using binary classi cation for mass and non-mass lesions separately or when employing a multi-class classi cation. Breast MRI datasets consists of 243 (173 mass and 70 non-mass) lesions. Results show that RF variable importance used with RF-binary based classi cation optimized for mass and non-mass lesions separately o ers the best classi cation accuracy.

  3. MRI of fetal acquired brain lesions

    Acquired fetal brain damage is suspected in cases of destruction of previously normally formed tissue, the primary cause of which is hypoxia. Fetal brain damage may occur as a consequence of acute or chronic maternal diseases, with acute diseases causing impairment of oxygen delivery to the fetal brain, and chronic diseases interfering with normal, placental development. Infections, metabolic diseases, feto-fetal transfusion syndrome, toxic agents, mechanical traumatic events, iatrogenic accidents, and space-occupying lesions may also qualify as pathologic conditions that initiate intrauterine brain damage. MR manifestations of acute fetal brain injury (such as hemorrhage or acute ischemic lesions) can easily be recognized, as they are hardly different from postnatal lesions. The availability of diffusion-weighted sequences enhances the sensitivity in recognizing acute ischemic lesions. Recent hemorrhages are usually readily depicted on T2 (*) sequences, where they display hypointense signals. Chronic fetal brain injury may be characterized by nonspecific changes that must be attributable to the presence of an acquired cerebral pathology. The workup in suspected acquired fetal brain injury also includes the assessment of extra-CNS organs that may be affected by an underlying pathology. Finally, the placenta, as the organ that mediates oxygen delivery from the maternal circulation to the fetus, must be examined on MR images

  4. Circumscribed lytic lesions of the thalassaemic skull

    Orzincolo, C.; Corcione, S.; Castaldi, G.; Bariani, L.; Franceschini, F.; Scutellari, P.N.

    1988-07-01

    Solitary or multiple circumscribed osteolytic areas are described in seven patients, selected from 250 patients with homozygous ..beta..-thalassaemia (Cooley's anaemia). On X-ray examinations, these areas appear as purely osteolytic lesions with well-defined margins not associated with sclerosis. The possible mechanisms are discussed.

  5. Scoliosis secondary to an unusual rib lesion.

    Burke, N G

    2012-04-01

    Tumours of the chest wall are uncommon and are usually malignant. A bone haemangioma is a rare benign vascular neoplasm, which more commonly occurs in middle-aged patients. We present the case of a scoliosis caused by a rib haemangioma in an adolescent male. Other causes of scoliosis secondary to rib lesions are discussed.

  6. Roentgenologic diagnostics of capsular ligament lesions

    Wirth, C.J.; Jaeger, M.

    1981-10-01

    The X-ray diagnostic is of obvious importance and relevance in the detection of acute or old capsular ligament lesions of the limb joint. On the one hand it serves as the plain radiograph (roentgenogram without contrast medium) for the assessment of osseous secondary lesions, for the documentation of luxationary positions of the joint partners, and in old capsular ligament lesions for the detection of an already existing arthrosis. On the other hand the X-ray images are of main importance, which are made from the hand-held limb in order to permit a comparison of the two sides, and which beyond the clinical detection of a joint instability indicate the extent and the direction of this instability and which also document it, and which allow in adolescents to recognize a separation of the epiphysis as an alternative to the capsular ligament rupture. Only in particular cases arthrography can provide some additional information, so for example in the case of an isolated syndesmosis rupture, ruptures of the rosette of the rotator muscle or of a damaged triangular disk in the hand. Angiography is only required in cases of traumatic luxations of the knee in order to exclude an intimal lesion of the popliteal artery.

  7. DEGENERATED SOFT TISSUE LESION RESEMBLING A CHONDROMA

    Alba

    2014-08-01

    Full Text Available A 42 year old male fisherman presented with a tender mass in the right side groin/root of the thigh. The entire episode followed a trauma. A biopsy specimen revealed a chondroma like lesion with necrosis. The final diagnosis made was Necrosis of Tendon.

  8. International Consensus for ultrasound lesions in gout

    Gutierrez, Marwin; Schmidt, Wolfgang A; Thiele, Ralf G;

    2015-01-01

    OBJECTIVE: To produce consensus-based definitions of the US elementary lesions in gout and to test their reliability in a web-based exercise. METHODS: The process consisted of two steps. In the first step a written Delphi questionnaire was developed from a systematic literature review and expert ...

  9. Assessing Elementary Lesions in Gout by Ultrasound

    Terslev, Lene; Gutierrez, Marwin; Christensen, Robin;

    2015-01-01

    OBJECTIVE: To test the reliability of the consensus-based ultrasound (US) definitions of elementary gout lesions in patients. METHODS: Eight patients with microscopically proven gout were evaluated by 16 sonographers for signs of double contour (DC), aggregates, erosions, and tophi in the first...

  10. Lesion mapping of social problem solving

    Aron K Barbey; Colom, Roberto; Paul, Erick J.; Chau, Aileen; Solomon, Jeffrey; Grafman, Jordan H.

    2014-01-01

    Barbey et al. investigate the neurobiology of social problem solving and its relation to psychometric intelligence, emotional intelligence, and personality in 144 patients with focal lesions. Results reveal the neural architecture of social problem solving and provide an integrative framework for understanding the social, psychometric, and emotional foundations of human intelligence.