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Sample records for al ecocardiograma doppler

  1. Avaliação do ventrículo direito pelo ecocardiograma com doppler tecidual na embolia pulmonar aguda

    Directory of Open Access Journals (Sweden)

    Ana Clara Tude Rodrigues

    2013-06-01

    Full Text Available FUNDAMENTO: A avaliação da função Ventricular Direita (VD pelo ecocardiograma em pacientes com Tromboembolismo Pulmonar (TEP é complexa, frequentemente qualitativa; o Doppler tecidual tem sido utilizado para avaliação semiquantitativa dessa câmara, com algumas limitações. OBJETIVO: Avaliar a função do VD no TEP pelo ecocardiograma com Doppler tecidual, complementando com o peptídeo atrial natriurético (BNP. MÉTODOS: Foram estudados pacientes com TEP pelo ecocardiograma com Doppler tecidual e BNP até 24 horas do diagnóstico, obtendo-se as velocidades miocárdicas (s', strain, strain rate e índice de performance miocárdica do VD; disfunção do VD foi iagnosticada por hipocinesia da câmara, movimento anormal septal e relação VD/VE >1. De acordo com o BNP os pacientes foram divididos em Grupo I, BNP 50 pg/mL. RESULTADOS: De 118 pacientes, 100 (60 homens, idade = 55 ± 17 anos foram analisados; observou-se disfunção do VD em 28%, mais frequentemente no grupo II (19 vs. 9 pacientes, p < 0,001. O grupo II era mais idoso (64 ± 19 vs. 50 ± 15 anos, apresentava menor velocidade de s' (10,5 ± 3,5 vs. 13,2 ± 3,1 cm/s e maior pressão pulmonar (48 ± 11 vs. 35 ± 11 mmHg, p < 0,001 para todos. O ponto de corte de s' para disfunção do VD foi de 10,8 cm/s (especificidade = 85%, sensibilidade = 54%, com moderada correlação entre o BNP e a onda s'(r = -0,39. CONCLUSÃO: No TEP, a disfunção do VD pelo ecocardiograma se acompanha de elevação do BNP; apesar confirmar adequadamente a presença de disfunção do VD, o Doppler tecidual apresenta sensibilidade limitada para este diagnóstico.

  2. Características cinefluoroscópicas de ocho modelos de prótesis mecánicas bivalvas implantadas en la República Argentina: su valor complementario al ecocardiograma Doppler color

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    Tomás F. Cianciulli

    2008-01-01

    Full Text Available Los diferentes modelos de prótesis valvulares mecánicas son numerosos y su reconocimiento por ecocardiografía es difícil. La cinefluoroscopia (CF puede complementar su identificación y su evaluación.Objetivos1 Describir las características cinefluoroscópicas de cada prótesis para su identificación. 2 Evaluar su función mediante la comparación de los gradientes del eco-Doppler con el ángulo de apertura de los discos basculantes en la CF. 3 Reconocer la capacidad de la CF para diferenciar prótesis normales de prótesis disfuncionantes.Material y métodosSe evaluaron prospectivamente 219 prótesis implantadas en 191 pacientes. Se excluyeron 14 prótesis debido a la coexistencia de disfunción sistólica ventricular izquierda grave. El análisis se realizó sobre 205 prótesis (142 aórticas y 63 mitrales.ResultadosA través de las características del anillo y de los discos, mediante la CF se logró identificar el modelo de la prótesis en el 100% de las válvulas. La movilidad de los discos permitió diferenciar prótesis normales de disfuncionantes (ángulo de apertura 79,3° ± 5,4° versus 58,7° ± 15°, respectivamente. En la CF no se pudieron perfilar los discos y/o el anillo en el 3,9% de las prótesis aórticas y en el 19,2% de las mitrales.De las 142 prótesis aórticas, el eco-Doppler identificó 112 normales y 30 disfuncionantes y de las 63 prótesis mitrales identificó 52 normales y 11 disfuncionantes.Al correlacionar ambos métodos, la sensibilidad, la especificidad, el valor predictivo positivo y el valor predictivo negativo de la fluoroscopia para diferenciar prótesis normales de disfuncionantes fueron del 71%, 93%, 67% y 94%, respectivamente.Conclusiones1 Cada modelo de prótesis valvular tiene características cinefluoroscópicas que permiten su identificación. 2 La cinefluoroscopia evalúa el funcionamiento de las prótesis mecánicas y distingue una normal de una disfuncionante. 3 Cuando hay gradientes altos y

  3. Síndrome do coração partido (Síndrome de Takotsubo induzida por ecocardiograma de estresse com dobutamina Síndrome del corazón roto (síndrome de Tako-Tsubo inducido por ecocardiograma de esfuerzo con dobutamina Dobutamine stress echocardiography-induced broken heart syndrome (Takotsubo Syndrome

    Directory of Open Access Journals (Sweden)

    Francisco Juarez Cruz de Vasconcelos Filho

    2009-07-01

    Full Text Available Relatamos um caso de síndrome de Takotsubo induzida por ecocardiograma de estresse com dobutamina em uma paciente de 76 anos, hipertensa com queixas clínicas de dor precordial, em consulta cardiológica eletiva. Para exclusão de dor torácica de etiologia coronariana foi solicitado ecocardiograma de estresse com dobutamina. O exame foi realizado e, no pico do esforço máximo, o ecocardiograma mostrou acinesia apical com o eletrocardiograma mostrando supradesnivelamento do segmento ST em D1, AVL e V2. A paciente foi internada e submetida a coronariografia, que mostrou coronárias normais e VE com balonamento apical. A paciente evoluiu estável com reversão do quadro 21 dias após o quadro inicial.Relatamos un caso de síndrome de Tako-Tsubo inducido por ecocardiograma de esfuerzo con dobutamina en una paciente de 76 años, hipertensa con quejas clínicas de dolor precordial, en consulta cardiológica electiva. Para exclusión de dolor torácico de etiología coronaria se solicitó ecocardiograma de esfuerzo con dobutamina. El examen fue realizado, y en el pico de esfuerzo máximo, el ecocardiograma mostró acinesia apical con el electrocardiograma mostrando supradesnivel del segmento ST en D1, AVL y V2. La paciente fue internada y sometida a coronariografía, que mostró coronarias normales y VI con abombamiento apical. La paciente evolucionó estable con reversión del cuadro 21 días después del cuadro inicial.We report a case of dobutamine stress echocardiography-induced Takotsubo syndrome in a 76-year-old hypertensive patient with clinical complaints of chest pain in an elective visit to the cardiologist. Dobutamine-stress-echocardiography was requested to rule out chest pain of coronary origin. During the test, at peak exercise, echocardiogram showed apical akinesia and electrocardiogram showed ST-segment elevation in D1, AVL, and V2. The patient was hospitalized and underwent coronary angiography, which showed normal coronary arteries

  4. Papel do ecocardiograma na avaliação ventricular do coração transplantado versus rejeição cardíaca

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    Gabriel Antonio Stanisci Miguel

    2012-11-01

    Full Text Available FUNDAMENTO: O Transplante Cardíaco (TC é uma alternativa para os indivíduos com doença cardíaca terminal. Na evolução pós-transplante, a ocorrência de episódios de Rejeição Cardíaca (RC é evento frequente que aumenta a morbimortalidade, sendo necessário o emprego de exame não invasivo com boa acurácia para seu diagnóstico, pois a Biópsia Endomiocárdica (BEM não é um procedimento isento de complicações. OBJETIVO: Comparar parâmetros obtidos com o princípio Doppler, entre os pacientes transplantados com RC (TX1 e os pacientes transplantados sem rejeição (TX0; utilizando como referência o Grupo Controle (GC e observando o comportamento da função sistodiastólica ventricular esquerda expressa por meio do Índice de Performance Miocárdica (IPM. MÉTODOS: Foram realizados ecocardiogramas transtorácicos no período de janeiro de 2006 a janeiro de 2008, para a avaliação prospectiva de 47 pacientes, subdivididos em GC (36,2%, TX0 (38,3% e TX1 (25,5%, comparando-se o IPM entre eles. Para a análise dos dados foram realizados os testes exato de Fisher e o não paramétrico de Kruskal-Wallis, ambos com nível de significância de 5%. RESULTADOS: Os grupos não diferiram em relação a idade, peso, altura e superfície corpórea. Quando comparado ao GC, TX0 e TX1 apresentaram alteração da função sistodiastólica ventricular esquerda, expressa como aumento do IPM, que foi mais intenso no TX1 [0,38 (0,29 - 0,44 X 0,47 (0,43 - 0,56 X 0,58 (0,52 - 0,74 p < 0,001]. CONCLUSÃO: O ecocardiograma mostrou-se como exame de boa acurácia na detecção das alterações da função sistodiastólica do coração transplantado; entretanto, não foi confiável como método substituto da BEM para o diagnóstico seguro de RC.

  5. Pre-precipitation studies in an Al-Zn alloy by positron Doppler broadening measurements

    International Nuclear Information System (INIS)

    Panchanadeeswaran, S.; Plichta, M.R.; Byrne, J.G.

    1984-01-01

    Positron annihilation studies using measurements of Doppler broadening of annihilation γ-rays have been carried out in an Al-8.5 wt% Zn alloy. More than 90% of positron trapping is believed to occur at GP zones formed on quenching the supersaturated solid solution. The dissolution of GP zones above 373 K was revealed by drastic narrowing of the Doppler energy spectrum for samples aged above 373 K. The kinetics of formation of GP zones at ambient temperatures is drastically reduced when the alloy containing GP zones formed during quenching from supersaturated solid solution was reverted at 403 K and reaged at ambient temperature. It was also observed that, even after long reageing, the total number of GP zones formed is much lower than in a directly quenched alloy. The kinetics of formation of GP zones are also reduced by quenching from a single phase to an intermediate temperature where GP zones are not stable, followed by ageing at ambient temperature. Transmission electron micrographs revealed the presence of dislocation loops in alloys quenched from temperature above 773 K. The sensitivity of positrons to the presence of dislocation loops was analysed using the R parameter analysis. (author)

  6. Electron Emission by Doppler-Mediated Formation of Doubly Excited H -** in Grazing Incidence of Protons on Clean Al(111)

    Czech Academy of Sciences Publication Activity Database

    Lörinčík, Jan; Šroubek, Zdeněk; Aumayr, H.; Winter, H. P.

    2001-01-01

    Roč. 54, č. 5 (2001), s. 633-639 ISSN 0295-5075 R&D Projects: GA AV ČR IAA1067801 Institutional research plan: CEZ:AV0Z4040901 Keywords : ion scattering from surfaces * Doppler-mediated formation * Al(111) Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.304, year: 2001

  7. Three-gamma annihilation of ortho-positronium in NiO/γ-Al2O3 catalysts detected by positron lifetime and coincidence Doppler broadening measurements

    International Nuclear Information System (INIS)

    Huang, S.H.; Chen, Z.Q.; Zhang, H.J.

    2012-01-01

    The pore structure of NiO/γ-Al 2 O 3 catalysts is characterized by positron lifetime and Doppler broadening measurements. A very long lifetime τ 4 of 92 ns is resolved from the positron lifetime spectrum measured for pure Al 2 O 3 , which could be attributed to the ortho-positronium (o-Ps) lifetime in large pores. It was also found that the fitted lifetime τ 4 and its corresponding intensity I 4 obtained from the lifetime spectra both decrease with narrowing energy window of the stop channel in the fast–fast coincidence lifetime measurement system. This suggests that the ultra long lifetime is primarily due to the self annihilation of o-Ps which emits three gamma-rays. Such 3γ annihilation is further evidenced by measuring the Doppler broadening of annihilation gamma rays in coincidence with the prompt gamma rays (1.28 MeV) emitted from the 22 Na positron source. In NiO/γ-Al 2 O 3 catalysts both the lifetime τ 4 and its intensity I 4 decreases with increasing NiO content (from 3 wt% to 40 wt%), which indicates decreasing of the number of 3γ events. The 3γ annihilation parameter analyzed from the coincidence Doppler broadening spectrum shows consistent decrease with increasing NiO content. - Highlights: ► Above paper reported study of the 3-gamma annihilation of o-Ps. ► 3γ annihilation was verified by varying the energy window of the lifetime system. ► A new coincidence Doppler broadening technique is also used to record 3γ events. ► 3γ parameter decreases with NiO content in NiO/γ-Al 2 O 3 catalysts.

  8. Disfunción diastólica asintomática en pacientes diabéticos tipo 2

    OpenAIRE

    Blanco Anesto, Jorge; Vázquez Vigoa, Alfredo; Bazán Milán, Manuel; Matilde Socarrás, María

    2003-01-01

    Se realizó un estudio descriptivo, de corte transversal, a un grupo de 38 pacientes diabéticos tipo 2, para determinar la frecuencia de disfunción diastólica asintomática y evaluar su posible asociación con otras variables. A todos se les realizó electrocardiograma, ecocardiograma, prueba ergométrica y ecocardiograma bidimensional y doppler pulsado para determinar la presencia de disfunción diastólica asintomática. Se les tomó una muestra de sangre para los indicadores de control metabólico. ...

  9. Betabloqueador tópico pode determinar resultados inconclusivos no ecocardiograma sob estresse com dobutamina em pacientes com glaucoma Topical betablocker use can result in inconclusive dobutamine stress echocardiography in patients with glaucoma

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    Adriana Cordovil

    2007-07-01

    Full Text Available O ecocardiograma sob estresse com dobutamina é um método bem estabelecido para avaliar doença arterial coronária, cuja sensibilidade tem sido potencializada pela adição de atropina no final do protocolo. Indivíduos com glaucoma, doença com alta prevalência em pacientes cardiopatas com mais de 40 anos, não podem se beneficiar do uso de atropina por ser contra-indicada neste grupo. Além disso, estes indivíduos são tratados freqüentemente com betabloqueadores tópicos (colírios, que podem exercer efeitos sistêmicos diminuindo a freqüência cardíaca, pressão arterial e capacidade pulmonar. O objetivo do nosso trabalho foi verificar se a ocorrência de um possível efeito sistêmico causado por estes colírios, causando baixa resposta cronotrópica, poderia determinar resultados inconclusivos no ecocardiograma sob estresse pela dobutamina nestes pacientes com glaucoma.Dobutamine stress echocardiography is a well-established method to assess coronary artery disease, of which sensitivity has been enhanced by adding atropine at the end of the protocol. Individuals with glaucoma, a disease with a high prevalence in patients with cardiac diseases older than 40 years, cannot benefit from the use of atropine as it is contraindicated for this group of patients. Additionally, these individuals are often treated with topical betablockers (eye drops, which can have systemic effects by decreasing cardiac frequency, blood pressure and pulmonary capacity. The aim of our study was to verify whether a possible systemic effect caused by the use of these eye drops, yielding a low chronotropic response, could result in inconclusive dobutamine stress echocardiography in patients with glaucoma.

  10. Coincidence Doppler broadening and 3DAP study of the pre-precipitation stage of an Al-Li-Cu-Mg-Ag alloy

    International Nuclear Information System (INIS)

    Honma, T.; Yanagita, S.; Hono, K.; Nagai, Y.; Hasegawa, M.

    2004-01-01

    Pre-precipitation solute clustering in Al-Li-Cu-Mg-Ag and Al-Cu-Mg-Ag alloys has been investigated by coincidence Doppler broadening (CDB) spectroscopy of positron annihilation and three-dimensional atom probe (3DAP) analysis. Although Ag-Mg co-clusters form in the Al-Cu-Mg-Ag alloy in the early stage of aging, no evidence for the co-cluster formation was obtained from the Li containing alloy using 3DAP. While CDB spectra indicated that vacancies are associated with Ag after aging for 15 s in the Al-Cu-Mg-Ag alloy, vacancy-Ag association is suppressed in the Li containing alloy. Based on the 3DAP and CDB results, the reasons for the completely different clustering behaviors observed in these two similar alloys are discussed

  11. Correlation between Spectral Index and Doppler Factor for a ...

    Indian Academy of Sciences (India)

    Abstract. Relativistic beaming effect is important for blazars. In a very recent work, γ-ray Doppler factors were calculated for a sample of Fermi blazars (Fan et al. 2013). In this work, we investigated the correlation between the Doppler factor and the effective spectral index, αOX, and found an anticorrelation between them.

  12. The use ofDoppler velocitnetry ofthe utnbilical artery before 24 ...

    African Journals Online (AJOL)

    growth retardation with umbilical artery Doppler ultrasonography. BM] 1989; 298: 631-635. 12. Schulman H, Winter D, Farmakides G, er al. Pregnancy surveil- lance with Doppler velocimerry of the uterine and umbilical arter- ies. Am] Obstet Gyneco11989; 160: 192-196. 13. Hanrerry KP, Primrose MH, Neilson JP, Whittle MJ.

  13. Lorentz invariance and the rotor Doppler shift experiments

    International Nuclear Information System (INIS)

    Rodrigues Junior, W.A.; Tiomno, J.

    1984-01-01

    It is shown that 'Rotor Doppler shift Experiments' provide a way to distinguish Einstein's Special Relativity (SR) from Lorentz's Aether Theory (LAT). Misconceptions in previous papers involving the Doppler shift experiments are examined. The theoretical and experimental data available on rotor Doppler shift experiments are analysed. Two models of SR violating theories are used to predict the output of a recently proposed experiment by Torr and Kolen. The first one corresponds to (strict) LAT and the other to an extended form of LAT Contrary to the first, the second theory leads to results in agreement with the preliminary experimental data of Torr et al indicating a breakdown both of SR and strict LAT. (Author) [pt

  14. Lorentz invariance and the rotor Doppler shift experiments

    International Nuclear Information System (INIS)

    Rodrigues Junior, W.A.; Tiomno, J.

    1984-01-01

    It is shown that 'Rotor Doppler shift Experiments' provide a way to distinguish Einstein's Special Relativity (SR) from Lorentz's Aether Theory (LAT). Misconceptions in previous papers involving the Doppler shift experiments are examined. The theoretical and experimental data available on rotor Doppler shift experiments are analysed. Two models of SR violating theories are used to predict the output of a recently proposed experiment by Torr and Kolen. The first one corresponds to (strict) LAT and the other to an extended form of LAT. Contrary to the first, the second theory leads to results in agreement with the preliminary experimental data of Torr et al indicating a breakdown both of SR and strict LAT. (Author) [pt

  15. A comparison of the doppler-broadened positron annihilation spectra of neutron irradiated Al 2O 3 and MgAl 2O 3

    Science.gov (United States)

    Jones, P. L.; Schaffer, J. P.; Cocks, F. H.; Clinard, F. W.; Hurley, G. F.

    1985-01-01

    Radiation damage studies of oxides and ceramics have become of increasing importance due to the projected use of these materials in thermonuclear fusion reactors as electronic insulators and first wall materials. In addition these materials are important in RAD waste disposal. As part of a study of the defect structure in radiation damaged ceramics Doppler-broadened positron annihilation spectra have been obtained for a series of single crystal sapphire (α-Al 2O 3) and polycrystal (1:1) and (1:2) magnesium aluminate spinel (MgO·Al 2O 3 and MgO-2Al 2O 3) samples. These samples were irradiated in EBR-II to a fluence of 3 × 10 25 n/m 2 (E > 0.1 MeV) at 740°C, and 2 × 10 26 n/m 2 (E > 0.1 MeV) at ~ 550°C respectively. Positron annihilation spectra lineshapes for the irradiated, annealed, and as-received samples of both materials were compared using S parameter analysis. These calculations were made on deconvoluted gamma ray spectra that were free of any instrumental broadening effects. In this way, absolute S parameter changes could be calculated. The observed changes in the S parameter are consistent with independent volume swelling measurements for both the α-A1 2O 3 and the (1:2) MgAl 2O 4 samples. However, the change in S parameter measured for the (1:1) spinel is contrary to the measured volume change. This apparent anomaly indicates a predominence of interstitial as opposed to vacancy type defects in this material.

  16. Síndrome de perfusión arterial invertida en un gemelo (acardia-acrania): Caso clínico

    OpenAIRE

    Bello B, Lucero; Sccucess M, María

    2001-01-01

    Se presenta el caso de un feto con acardia y acrania, producto de embarazo gemelar complicado con el síndrome de perfusión arterial invertida, cuyo diagnóstico se sospechó ecográficamente por el hallazgo de acrania y ausencia de actividad cardíaca y se confirmó con la aplicación del ultrasonido Doppler pulsado. El manejo perinatal consistió en la realización de ecocardiograma fetal y ecosonograma Doppler en forma periódica como recurso para controlar y pronosticar el grado de descompensación ...

  17. Endocarditis trombótica no bacteriana bivalvular asociada a cáncer y ecocardiograma transesofágico Bivalvular non bacterial thrombotic endocarditis associated with cancer and transesophageal echocardiography

    Directory of Open Access Journals (Sweden)

    Marcelo Zylberman

    2006-06-01

    Full Text Available La endocarditis trombótica no bacteriana es la causa más frecuente de accidente cerebrovascular isquémico en pacientes con cáncer. En estos pacientes se hallaron vegetaciones valvulares hasta en el 9% de las autopsias. Sin embargo, la afección bivalvular es poco frecuente, observándose en el 9% de las endocarditis trombóticas. Se presenta una paciente con cáncer de ovario que presentó afasia e imágenes compatibles con isquemia cerebral. El ecocardiograma transtorácico fue normal. El ecocardiograma transesofágico evidenció vegetaciones en las válvulas aórtica y mitral. Se enfatiza la importancia de sospechar endocarditis trombótica no bacteriana en enfermos con cáncer y embolismo sistémico y en la escasa frecuencia de afección bivalvular.Non bacterial thrombotic endocarditis is the most frequent cause of ischemic stroke in cancer patients. Up to 9% of autopsies of cancer patients show non infectious valvular masses. However, bivalvular involvement is not frequently occurring in 9% of non bacterial thrombotic endocarditis. We report a patient with ovarian cancer who presented aphasia. The MRI was compatible with cerebral ischemia. The transthoracic echocardiogram was normal and a transesophageal echocardiogram showed vegetations in aortic and mitral valves. We emphasize the importance of suspecting non bacterial thrombotic endocarditis in patients with cancer and systemic embolism and the low frequency of bivalvular involvement.

  18. An Observational Study of a Prefrontal Convective Rainband Using Tamex Single-and Dual-Doppler Data

    Science.gov (United States)

    1991-01-01

    integration from the surface. Other Doppler studies, e.g., Chong and Testud (1983), Lin et al. 37 (1986), etc, also showed similiar results. 4.3 Variational...Atmos. Sci., 39, 258- 279. Chong, M., and J. Testud , 1983: Three-Dimensional Wind Field Analysis from Dual-Doppler Radar Data. Part III: The Boundary

  19. Sub-Doppler spectroscopy

    International Nuclear Information System (INIS)

    Hansch, T.W.

    1983-01-01

    This chapter examines Doppler-free saturation spectroscopy, tunable cw sources, and Doppler-free two-photon spectroscopy. Discusses saturation spectroscopy; continuous wave saturation spectroscopy in the ultraviolet; and two-photon spectroscopy of atomic hydrogen 1S-2S. Focuses on Doppler-free laser spectroscopy of gaseous samples. Explains that in saturation spectroscopy, a monochromatic laser beam ''labels'' a group of atoms within a narrow range of axial velocities through excitation or optical pumping, and a Doppler-free spectrum of these selected atoms is observed with a second, counterpropagating beam. Notes that in two-photon spectroscopy it is possible to record Doppler-free spectra without any need for velocity selection by excitation with two counterpropagating laser beams whose first order Doppler shifts cancel

  20. Doppler Tomography

    Science.gov (United States)

    Marsh, T. R.

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

  1. Análisis de perforantes de la epigástrica inferior profunda con Angio TC 3D, Eco Doppler color y Doppler simple de ultrasonidos en colgajo DIEP: resultados preliminares Analysis of deep inferior epigastric perforating vessels with 3D CT angiography, color Doppler ultrasonography and Doppler in diep flaps: preliminary results

    Directory of Open Access Journals (Sweden)

    J. Castro García

    2008-09-01

    Full Text Available Nuestro objetivo es la validación de la Angio TC tridimensional como herramienta de planificación de los colgajos DIEP, comparándolo con el Doppler de ultrasonidos (US y eco Doppler color. Entre enero de 2006 y marzo de 2007 se realiza en 11 pacientes (13 DIEP un estudio comparativo prospectivo entre el Doppler de US, eco Doppler color y Angio TC con reconstrucción tridimensional, utilizando como dato de referencia los hallazgos intraoperatorios. En dicho proceso se localiza la mejor perforante que pueda servir como pedículo al colgajo DIEP en función de su localización, calibre, trayecto y relaciones anatómicas con respecto al músculo. La Angio TC con reconstrucción tridimensional, demuestra una especificidad del 100% (IC 95% 75.3-100 lo que le convierte en una prueba con un alto valor predictivo positivo y una excelente herramienta en la planificación de los colgajos de perforantes. El eco Doppler color determinó, que tan sólo en un 46,1% (IC 95% 19,2-74,9 de los pacientes, la perforante seleccionada por la prueba de forma preoperatoria, coincidía con la perforante elegida en quirófano. Con el Doppler de US, en un 30,8 % (IC 95% 9,1-61,4 de los colgajos estudiados, coincidía la mejor perforante escogida de forma preoperatoria, con los hallazgos obtenidos tras la disección del colgajo. En el presente estudio, la Angio TC tridimensional se ha mostrado como una técnica con una gran especificidad que proporciona valiosa información, sólo comparable con la disección anatómica y por delante de pruebas como el Doppler de ultrasonidos y el eco Doppler color.The aim of this report, is to validate the Angio-CT technique with three-dimentional reconstruction as a preoperative planning tool, after comparison with Doppler ultrasound and color- Duplex. Between january 2006 and march 2007, we studied 11 consecutive patients (13 DIEP in whom a prospective comparative followed up was performed comparing, the findings observed using

  2. Spin-Orbit Misalignments of Three Jovian Planets via Doppler Tomography

    Science.gov (United States)

    Johnson, Marshall C.; Cochran, William D.; Addison, Brett C.; Tinney, Chris G.; Wright, Duncan J.

    2017-10-01

    We present measurements of the spin-orbit misalignments of the hot Jupiters HAT-P-41 b and WASP-79 b, and the aligned warm Jupiter Kepler-448 b. We obtain these measurements with Doppler tomography, where we spectroscopically resolve the line profile perturbation during the transit due to the Rossiter-McLaughlin effect. We analyze time series spectra obtained during portions of five transits of HAT-P-41 b, and find a value of the spin-orbit misalignment of λ =-{22.1}-6.0{+0.8^\\circ }. We reanalyze the radial velocity Rossiter-McLaughlin data on WASP-79 b obtained by Addison et al. using Doppler tomographic methodology. We measure λ =-{99.1}-3.9{+4.1^\\circ }, consistent with but more precise than the value found by Addison et al. For Kepler-448 b we perform a joint fit to the Kepler light curve, Doppler tomographic data, and a radial velocity data set from Lillo-Box et al. We find an approximately aligned orbit (λ =-{7.1}-2.8{+4.2^\\circ }), in agreement with the value found by Bourrier et al. Through analysis of the Kepler light curve we measure a stellar rotation period of {P}{rot}=1.27+/- 0.11 days, and use this to argue that the full three-dimensional spin-orbit misalignment is small, \\psi ˜ 0^\\circ . Based in part on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Stanford University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen.

  3. AMSNEXRAD-Automated detection of meteorite strewnfields in doppler weather radar

    Science.gov (United States)

    Hankey, Michael; Fries, Marc; Matson, Rob; Fries, Jeff

    2017-09-01

    For several years meteorite recovery in the United States has been greatly enhanced by using Doppler weather radar images to determine possible fall zones for meteorites produced by witnessed fireballs. While most fireball events leave no record on the Doppler radar, some large fireballs do. Based on the successful recovery of 10 meteorite falls 'under the radar', and the discovery of radar on more than 10 historic falls, it is believed that meteoritic dust and or actual meteorites falling to the ground have been recorded on Doppler weather radar (Fries et al., 2014). Up until this point, the process of detecting the radar signatures associated with meteorite falls has been a manual one and dependent on prior accurate knowledge of the fall time and estimated ground track. This manual detection process is labor intensive and can take several hours per event. Recent technological developments by NOAA now help enable the automation of these tasks. This in combination with advancements by the American Meteor Society (Hankey et al., 2014) in the tracking and plotting of witnessed fireballs has opened the possibility for automatic detection of meteorites in NEXRAD Radar Archives. Here in the processes for fireball triangulation, search area determination, radar interfacing, data extraction, storage, search, detection and plotting are explained.

  4. Comparisons between PW Doppler system and enhanced FM Doppler system

    DEFF Research Database (Denmark)

    Wilhjelm, Jens E.; Pedersen, P. C.

    1995-01-01

    This paper presents a new implementation of an echo-ranging FM Doppler system with improved performance, relative to the FM Doppler system reported previously. The use of long sweeps provides a significant reduction in peak to average power ratio compared to pulsed wave (PW) emission. A PW Doppler...... system exploits the direct relationship between arrival time of the received signal and range from the transducer. In the FM Doppler systems, a similar relationship exists in the spectral domain of the demodulated received signals, so that range is represented by frequency. Thus, a shift in location...... of moving scatterers between consecutive emissions corresponds to a frequency shift in the spectral signature. The improvement relative to the earlier version of the FM Doppler system is attained by utilizing cross-correlation of real spectra rather than of magnitude spectra for assessing flow velocity...

  5. Avaliação da anastomose de artéria torácica interna esquerda com artéria interventricular anterior pela ecodopplercardiografia Evaluation of left internal thoracic artery anastomosis with left anterior descending coronary artery by Doppler echocardiography

    Directory of Open Access Journals (Sweden)

    Adelaide Arruda

    1997-12-01

    Full Text Available OBJETIVO: Avaliar o valor do ecocardiograma Doppler(ECO transtorácico na identificação de perviabilidade da anastomose entre artéria torácica interna esquerda (ATIE e interventricular anterior, realizada pela técnica de revascularização miocárdica pela minitoracotomia sem circulação extracorpórea. MÉTODOS: Estudaram-se os primeiros 12 pacientes, consecutivos, no período de pós-operatório intra-hospitalar pelo ECO, utilizando-se transdutores de 5MHz, pela via paraesternal esquerda, preferencialmente. Foram analisadas velocidades máximas e integrais de velocidade dos componentes sistólico e diastólico das curvas espectrais de fluxo Doppler. Todos pacientes foram submetidos à cinecoronariografia, enquanto hospitalizados. RESULTADOS: O ECO foi exeqüível em 93% dos pacientes. Nos com anastomose pérvia (6/7, observou-se ao estudo Doppler amplo componente diastólico (padrão A. Naqueles com anastomose obstruída (4/4 o padrão observado foi de predomínio sistólico (padrão B (p=0,003*. CONCLUSÃO: O ECO da ATIE anastomosada com a artéria interventricular anterior, após cirurgia de revascularização miocárdica pela técnica de minitoracotomia, permitiu caracterizar precocemente, com precisão, a perviabilidade da anastomose.PURPOSE: To study the value of Doppler echocardiography as a tool for the evaluation of left internal thoracic artery graft (LITAG patency in patients who underwent coronary revascularization using minimally invasive bypass surgery without extracorporeal circulation. METHODS: The first 12 consecutive patients were studied after coronary artery bypass surgery using a 5MHz Doppler transducer. Doppler signals for the systolic and diastolic flow velocities were preferably obtained in the second intercostal space. All patients underwent coronary angiography while hospitalized. RESULTS: The exam was feasible in 93% of patients. Doppler flow pattern was predominantly diastolic (pattern A in patients with patent

  6. Ultrasonography with color Doppler and power Doppler in the diagnosis of periapical lesions

    International Nuclear Information System (INIS)

    Goel, Sumit; Nagendrareddy, Suma Gundareddy; Raju, Manthena Srinivasa; Krishnojirao, Dayashankara Rao Jingade; Rastogi, Rajul; Mohan, Ravi Prakash Sasankoti; Gupta, Swati

    2011-01-01

    To evaluate the efficacy of ultrasonography (USG) with color Doppler and power Doppler applications over conventional radiography in the diagnosis of periapical lesions. Thirty patients having inflammatory periapical lesions of the maxillary or mandibular anterior teeth and requiring endodontic surgery were selected for inclusion in this study. All patients consented to participate in the study. We used conventional periapical radiographs as well as USG with color Doppler and power Doppler for the diagnosis of these lesions. Their diagnostic performances were compared against histopathologic examination. All data were compared and statistically analyzed. USG examination with color Doppler and power Doppler identified 29 (19 cysts and 10 granulomas) of 30 periapical lesions accurately, with a sensitivity of 100% for cysts and 90.91% for granulomas and a specificity of 90.91% for cysts and 100% for granulomas. In comparison, conventional intraoral radiography identified only 21 lesions (sensitivity of 78.9% for cysts and 45.4% for granulomas and specificity of 45.4% for cysts and 78.9% for granulomas). There was definite correlation between the echotexture of the lesions and the histopathological features except in one case. USG imaging with color Doppler and power Doppler is superior to conventional intraoral radiographic methods for diagnosing the nature of periapical lesions in the anterior jaws. This study reveals the potential of USG examination in the study of other jaw lesions

  7. Dual-Doppler Feasibility Study

    Science.gov (United States)

    Huddleston, Lisa L.

    2012-01-01

    When two or more Doppler weather radar systems are monitoring the same region, the Doppler velocities can be combined to form a three-dimensional (3-D) wind vector field thus providing for a more intuitive analysis of the wind field. A real-time display of the 3-D winds can assist forecasters in predicting the onset of convection and severe weather. The data can also be used to initialize local numerical weather prediction models. Two operational Doppler Radar systems are in the vicinity of Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS); these systems are operated by the 45th Space Wing (45 SW) and the National Weather Service Melbourne, Fla. (NWS MLB). Dual-Doppler applications were considered by the 45 SW in choosing the site for the new radar. Accordingly, the 45th Weather Squadron (45 WS), NWS MLB and the National Aeronautics and Space Administration tasked the Applied Meteorology Unit (AMU) to investigate the feasibility of establishing dual-Doppler capability using the two existing systems. This study investigated technical, hardware, and software requirements necessary to enable the establishment of a dual-Doppler capability. Review of the available literature pertaining to the dual-Doppler technique and consultation with experts revealed that the physical locations and resulting beam crossing angles of the 45 SW and NWS MLB radars make them ideally suited for a dual-Doppler capability. The dual-Doppler equations were derived to facilitate complete understanding of dual-Doppler synthesis; to determine the technical information requirements; and to determine the components of wind velocity from the equation of continuity and radial velocity data collected by the two Doppler radars. Analysis confirmed the suitability of the existing systems to provide the desired capability. In addition, it is possible that both 45 SW radar data and Terminal Doppler Weather Radar data from Orlando International Airport could be used to alleviate any

  8. Ultrasonography with color Doppler and power Doppler in the diagnosis of periapical lesions

    Science.gov (United States)

    Goel, Sumit; Nagendrareddy, Suma Gundareddy; Raju, Manthena Srinivasa; Krishnojirao, Dayashankara Rao Jingade; Rastogi, Rajul; Mohan, Ravi Prakash Sasankoti; Gupta, Swati

    2011-01-01

    Aim: To evaluate the efficacy of ultrasonography (USG) with color Doppler and power Doppler applications over conventional radiography in the diagnosis of periapical lesions. Materials and Methods: Thirty patients having inflammatory periapical lesions of the maxillary or mandibular anterior teeth and requiring endodontic surgery were selected for inclusion in this study. All patients consented to participate in the study. We used conventional periapical radiographs as well as USG with color Doppler and power Doppler for the diagnosis of these lesions. Their diagnostic performances were compared against histopathologic examination. All data were compared and statistically analyzed. Results: USG examination with color Doppler and power Doppler identified 29 (19 cysts and 10 granulomas) of 30 periapical lesions accurately, with a sensitivity of 100% for cysts and 90.91% for granulomas and a specificity of 90.91% for cysts and 100% for granulomas. In comparison, conventional intraoral radiography identified only 21 lesions (sensitivity of 78.9% for cysts and 45.4% for granulomas and specificity of 45.4% for cysts and 78.9% for granulomas). There was definite correlation between the echotexture of the lesions and the histopathological features except in one case. Conclusions: USG imaging with color Doppler and power Doppler is superior to conventional intraoral radiographic methods for diagnosing the nature of periapical lesions in the anterior jaws. This study reveals the potential of USG examination in the study of other jaw lesions. PMID:22223940

  9. Ultrasonography with color Doppler and power Doppler in the diagnosis of periapical lesions

    Directory of Open Access Journals (Sweden)

    Sumit Goel

    2011-01-01

    Full Text Available Aim: To evaluate the efficacy of ultrasonography (USG with color Doppler and power Doppler applications over conventional radiography in the diagnosis of periapical lesions. Materials and Methods: Thirty patients having inflammatory periapical lesions of the maxillary or mandibular anterior teeth and requiring endodontic surgery were selected for inclusion in this study. All patients consented to participate in the study. We used conventional periapical radiographs as well as USG with color Doppler and power Doppler for the diagnosis of these lesions. Their diagnostic performances were compared against histopathologic examination. All data were compared and statistically analyzed. Results: USG examination with color Doppler and power Doppler identified 29 (19 cysts and 10 granulomas of 30 periapical lesions accurately, with a sensitivity of 100% for cysts and 90.91% for granulomas and a specificity of 90.91% for cysts and 100% for granulomas. In comparison, conventional intraoral radiography identified only 21 lesions (sensitivity of 78.9% for cysts and 45.4% for granulomas and specificity of 45.4% for cysts and 78.9% for granulomas. There was definite correlation between the echotexture of the lesions and the histopathological features except in one case. Conclusions: USG imaging with color Doppler and power Doppler is superior to conventional intraoral radiographic methods for diagnosing the nature of periapical lesions in the anterior jaws. This study reveals the potential of USG examination in the study of other jaw lesions.

  10. Is Doppler prediction of anemia effective in the growth-restricted fetus?

    Science.gov (United States)

    Makh, D S; Harman, C R; Baschat, A A

    2003-11-01

    To evaluate the utility of middle cerebral artery (MCA) and umbilical artery (UA) Doppler to predict anemia in intrauterine growth restricted (IUGR) fetuses. Fetuses with an abdominal circumference complete blood count was determined from a peripheral venous sample drawn at delivery. Anemia was defined as a hemoglobin value of references ranges by Mari et al. and Kurmanavicius et al.) were related to hemoglobin using linear regression analysis. In addition, UA absent end-diastolic velocity (AEDV), brain sparing (MCA PI > 2 SDs below gestational age mean), low CPR (> 2 SDs below gestational age mean) and an elevated MCA PSV (> 2 SDs) were evaluated for their predictive accuracy for anemia. Of 97 IUGR neonates 23 were anemic (23.7%). The MCA PSV was significantly related to hemoglobin using either reference range (Mari et al., F = 22.1577, Kurmanavicius et al., F = 21.8188, P < 0.001, respectively). However, using categorical cut-offs as well as regression analysis none of the Doppler parameters could be identified to provide clinically useful prediction of anemia. Parameters of MCA and UA vascular impedance and MCA PSV are significantly related to anemia in IUGR neonates. Despite this relationship the predictive accuracy is unacceptable for the clinical application in the setting of IUGR. Altered cardiovascular dynamics in IUGR fetuses may be responsible for this effect. Copyright 2003 ISUOG. Published by John Wiley & Sons, Ltd.

  11. Comparison of power Doppler and color Doppler ultrasonography in the detection of intrasticular blood flow of normal infants

    International Nuclear Information System (INIS)

    Shin, Sung Ran; Lee, Ho Kyoung; Lee, Won Gyun; Youk, Dong Joon; Rho, Taek Soo; Lee, Min Jin; Lee, Sang Chun

    1999-01-01

    To compare color Doppler ultrasonography (US) and power Doppler US in the detection of intratesticular blood flow in normal infants and to asses the symmetry of blood flow. Testicular blood flow was assessed prospectively in 100 testes of 50 infants with both power and color Doppler US. We compared the power Doppler with color Doppler to detect intratesticular blood. When the flow was detected, intratesticular blood flow was graded as follows: grade 1: single intratesticular Doppler signal ; grade 2: multiple intratesticular Doppler signals. The symmetry of intratesticular flow was assessed by using the same method. Intratesticular flow was detected in 72 (72%) and 68 (68%) testes on power and color Doppler US, respectively. In 76 testes (76%), intratesticular flow was detected in either one or both techniques. On power Doppler US, grade 1 was seen in 40 tests and grade 2 in 32 testes. On color Doppler US, grade 1 was noted in 52 testes and grade 2 in 16 testes. Testicular blood flow was symmetric on both power and color Doppler US in each patient. There was no difference between power Doppler and color Doppler ultrasonography in detecting intratesticular blood flow in normal infants.

  12. Ultrasonic colour Doppler imaging

    DEFF Research Database (Denmark)

    Evans, David H.; Jensen, Jørgen Arendt; Nielsen, Michael Bachmann

    2011-01-01

    Ultrasonic colour Doppler is an imaging technique that combines anatomical information derived using ultrasonic pulse-echo techniques with velocity information derived using ultrasonic Doppler techniques to generate colour-coded maps of tissue velocity superimposed on grey-scale images of tissue...... anatomy. The most common use of the technique is to image the movement of blood through the heart, arteries and veins, but it may also be used to image the motion of solid tissues such as the heart walls. Colour Doppler imaging is now provided on almost all commercial ultrasound machines, and has been...... vectors. This review briefly introduces the principles behind colour Doppler imaging and describes some clinical applications. It then describes the basic components of conventional colour Doppler systems and the methods used to derive velocity information from the ultrasound signal. Next, a number of new...

  13. Gallblader varices in children with portal cavernoma: duplex-Doppler and color Doppler ultrasound studies

    International Nuclear Information System (INIS)

    Muro, D.; Sanguesa, C.; Lopez, A.

    1998-01-01

    To determine the prevalence of varices in the gallbladder wall, observed by duplex-Doppler and color Doppler ultrasound, in children with cavernoma of the portal vein. Nineteen patients with portal hypertension were studied prospectively by duplex-Doppler and color Doppler ultrasound: 12 of the patients had developed a cavernoma of the portal vein. The presence of peri vesicular varices was assessed in the group of patients with portal cavernoma. Duplex-Doppler and color Doppler ultrasound disclosed the presence of varices in gallbladder wall in nine of the 12 patients (75%). The varices appeared as anechoic and serpiginous areas, and Doppler ultrasound revealed slowed venous flow. However, the three patients in whom gallbldder varices were not detected presented collateral gastric ciculation and spontaneous splenorenal shunt. Gallbladder varices are common in children with portal vein cavernoma; they present hepatopetal flow. Their developments is not related to the size of the portal cavernoma, the presence of spontaneous portosystemic shunts, or endoscopic obliteration of gastric and esophageal varices. The detection of gallbladder varices in patients with portal hypertension who are to undergo biliary surgery is highly important for the surgeon, helping to avoid perioperative complications. (Author) 15 refs

  14. Contrast-enhanced power Doppler US in the characterization of renal masses; Power Doppler con mezzo di contrasto nella caratterizzazione delle masse renali

    Energy Technology Data Exchange (ETDEWEB)

    Ascenti, G.; Zimbaro, G.; Mazziotti, S.; Visalli, C.; Racchiusa, S.; Vinci, S.; Scribano, E. [Messina Univ., Messina (Italy). Ist. di Scienze Radiologiche

    2000-09-01

    Purpose of this work is to report the results of a prospective study investigating the potentials of contrast-enhanced power Doppler in the diagnosis of expansive renal lesions. From 1997 to October 30, 1999, it was studied the case of 59 expansive renal lesions (28 malignant, 31 benign) in 48 patients (mean age 55 years, range 10-79) with power Doppler US before and after the administration of an echo-enhancing agent (Levovist, Schering AG, Berlin Germany). Were found 5 patterns of vascular architecture of the lesions, both before and after contrast agent administration, following the classification by Jinzaki e Coll. Power Doppler US showed vascular structures in 34 patients. The administration of Levovist revealed vessels in 12/25 lesions which had none at baseline studies and in 6 cases vascularity was particularly evident. Color signals were enhanced in all the 34 vascularized lesions, which allowed better definition of vascular patterns. The characterization of vascular patterns with baseline power Doppler US helped improve diagnostic accuracy compared to gray-scale US (58% versus 32%) for hyperechoic lesions, complex cysts and pseudomasses. Independent of contrast agent administration, the integration of gray-scale and power Doppler modes increased diagnostic accuracy even further (76% correct diagnoses). In our series, the US contrast agent did not increase the diagnostic accuracy of power Doppler in the differential diagnosis of hyperechoic renal lesions; conversely, Levovist can be advantageous for the characterization of suspected pseudomasses and complex cysts. [Italian] Scopo di questo articolo e' quello di riportare i risultati di uno studio prospettico finalizzato ad individuare le potenzialita' del power Doppler con mdc ecografico nella caratterizzazione delle lesioni espansive del rene. Dal 1997 al 30 ottobre 1999 sono state studiate 59 lesioni renali (28 maligne, 31 benigne) in 48 pazienti (eta' media 55 anni, intervallo 10

  15. Avaliação dos tumores hepáticos ao Doppler Doppler evaluation of liver tumors

    Directory of Open Access Journals (Sweden)

    Márcio Martins Machado

    2004-10-01

    Full Text Available Os avanços recentes na ultra-sonografia têm ampliado a possibilidade de detecção de tumores hepáticos. Isto tem auxiliado na perspectiva de melhora do prognóstico destes pacientes, à medida que novas técnicas terapêuticas têm surgido. Neste artigo os autores relatam achados ao Doppler que podem auxiliar na identificação e caracterização dos tumores hepáticos, avaliando dados do Doppler colorido, pulsado e do Doppler de amplitude ("power Doppler". Fazem, também, referência a novas modalidades de imagem, como o uso da harmônica.Recent advances in ultrasound have optimized the detection of liver tumors and helped to improve the prognosis of patients with this condition as newly developed and improved therapeutic modalities have been established. The authors review important Doppler findings which may help in the identification and characterization of some hepatic tumors through the evaluation of color Doppler, pulsed Doppler and power Doppler features. New imaging methods such as the use of harmonics imaging are also reviewed.

  16. Doppler evaluation of valvular stenosis

    International Nuclear Information System (INIS)

    Kisslo, J.; Krafchek, J.; Adams, D.; Mark, D.B.

    1986-01-01

    One of the reasons why use of Doppler echocardiography is growing rapidly is because of its utility in detecting the presence of valvular stenosis and in estimating its severity. Detection of the presence of stenotic valvular heart disease using Doppler echocardiography was originally described over 10 years ago. It has been demonstrated that Doppler blood velocity data could be used to estimate the severity of a stenotic lesion. This chapter discusses the evaluation of valvular stenois using Doppler

  17. The Cognitive Doppler.

    Science.gov (United States)

    Kozoil, Micah E.

    1989-01-01

    Discusses the learning needs of students in the concrete operational stage in mathematics. Identifies the phenomenon of reduced cognitive performance in an out-of-class environment as the "Cognitive Doppler." Suggests methods of reducing the pronounced effects of the Cognitive Doppler by capitalizing on the students' ability to memorize…

  18. Doppler ultrasound exam of an arm or leg

    Science.gov (United States)

    Peripheral vascular disease - Doppler; PVD - Doppler; PAD - Doppler; Blockage of leg arteries - Doppler; Intermittent claudication - Doppler; Arterial insufficiency of the legs - Doppler; Leg pain and ...

  19. Doppler flowmetry in preeclampsia.

    Science.gov (United States)

    Zahumensky, J

    2009-01-01

    The purpose of this study was to summarize the new published data on the Doppler flowmetry in preeclampsia. We summarize the new published data on the Doppler flowmetry in uteroplacental, fetoplacental and fetal circulation in preeclampsia. The present review summarized the results of clinical research on the Doppler flowmetry in the screening of risk of preclampsia, in the diagnosis of preclampsia and in the fetal risk in preclampsia (Ref. 19). Full Text (Free, PDF) www.bmj.sk.

  20. Steerable Doppler transducer probes

    International Nuclear Information System (INIS)

    Fidel, H.F.; Greenwood, D.L.

    1986-01-01

    An ultrasonic diagnostic probe is described which is capable of performing ultrasonic imaging and Doppler measurement consisting of: a hollow case having an acoustic window which passes ultrasonic energy and including chamber means for containing fluid located within the hollow case and adjacent to a portion of the acoustic window; imaging transducer means, located in the hollow case and outside the fluid chamber means, and oriented to direct ultrasonic energy through the acoustic window toward an area which is to be imaged; Doppler transducer means, located in the hollow case within the fluid chamber means, and movably oriented to direct Doppler signals through the acoustic window toward the imaged area; means located within the fluid chamber means and externally controlled for controllably moving the Doppler transducer means to select one of a plurality of axes in the imaged area along which the Doppler signals are to be directed; and means, located external to the fluid chamber means and responsive to the means for moving, for providing an indication signal for identifying the selected axis

  1. Doppler radar flowmeter

    Science.gov (United States)

    Petlevich, Walter J.; Sverdrup, Edward F.

    1978-01-01

    A Doppler radar flowmeter comprises a transceiver which produces an audio frequency output related to the Doppler shift in frequency between radio waves backscattered from particulate matter carried in a fluid and the radiated radio waves. A variable gain amplifier and low pass filter are provided for amplifying and filtering the transceiver output. A frequency counter having a variable triggering level is also provided to determine the magnitude of the Doppler shift. A calibration method is disclosed wherein the amplifier gain and frequency counter trigger level are adjusted to achieve plateaus in the output of the frequency counter and thereby allow calibration without the necessity of being able to visually observe the flow.

  2. Spatial weighting of Doppler reactivity feedback

    International Nuclear Information System (INIS)

    Carew, J.F.; Diamond, D.J.; Todosow, M.

    1977-12-01

    The spatial weighting of the local Doppler feedback implicit in the determination of the core Doppler feedback reactivity has been investigated. Using a detailed planar PDQ7-II PWR model with local fuel-temperature feedback, the core Doppler spatial weight factor, S, has been determined for various control patterns and power levels. Assuming power-squared weighting of the local Doppler feedback, a simple analytic expression for S has been derived and, based on comparison with the PDQ7-II results, provides a convenient and accurate representation of the Doppler spatial weight factor. The sensitivity of these results to variations in the fuel rod heat transfer coefficients, fuel loading and the magnitude of the Doppler coefficient has also been evaluated. The dependence of the local Doppler coefficient on moderator temperature, boron concentration and control rod density has been determined and found to be weak. Selected comparisons with vendor analyses have been made and indicate general agreement

  3. Ultrasonic colour Doppler imaging

    DEFF Research Database (Denmark)

    Evans, David H; Jensen, Jørgen Arendt; Nielsen, Michael Bachmann

    2011-01-01

    Ultrasonic colour Doppler is an imaging technique that combines anatomical information derived using ultrasonic pulse-echo techniques with velocity information derived using ultrasonic Doppler techniques to generate colour-coded maps of tissue velocity superimposed on grey-scale images of tissue...... anatomy. The most common use of the technique is to image the movement of blood through the heart, arteries and veins, but it may also be used to image the motion of solid tissues such as the heart walls. Colour Doppler imaging is now provided on almost all commercial ultrasound machines, and has been...

  4. Doppler ultrasound monitoring technology.

    Science.gov (United States)

    Docker, M F

    1993-03-01

    Developments in the signal processing of Doppler ultrasound used for the detection of fetal heart rate (FHR) have improved the operation of cardiotocographs. These developments are reviewed and the advantages and disadvantages of the various Doppler and signal processing methods are compared.

  5. Differential doppler heterodyning technique

    DEFF Research Database (Denmark)

    Lading, Lars

    1971-01-01

    Measuring velocity without disturbing the moving object is possible by use of the laser doppler heterodyning technique. Theoretical considerations on the doppler shift show that the antenna property of the photodetector can solve an apparent conflict between two different ways of calculating...

  6. Mesospheric gravity wave momentum flux estimation using hybrid Doppler interferometry

    Directory of Open Access Journals (Sweden)

    A. J. Spargo

    2017-06-01

    Full Text Available Mesospheric gravity wave (GW momentum flux estimates using data from multibeam Buckland Park MF radar (34.6° S, 138.5° E experiments (conducted from July 1997 to June 1998 are presented. On transmission, five Doppler beams were symmetrically steered about the zenith (one zenith beam and four off-zenith beams in the cardinal directions. The received beams were analysed with hybrid Doppler interferometry (HDI (Holdsworth and Reid, 1998, principally to determine the radial velocities of the effective scattering centres illuminated by the radar. The methodology of Thorsen et al. (1997, later re-introduced by Hocking (2005 and since extensively applied to meteor radar returns, was used to estimate components of Reynolds stress due to propagating GWs and/or turbulence in the radar resolution volume. Physically reasonable momentum flux estimates are derived from the Reynolds stress components, which are also verified using a simple radar model incorporating GW-induced wind perturbations. On the basis of these results, we recommend the intercomparison of momentum flux estimates between co-located meteor radars and vertical-beam interferometric MF radars. It is envisaged that such intercomparisons will assist with the clarification of recent concerns (e.g. Vincent et al., 2010 of the accuracy of the meteor radar technique.

  7. Mesospheric gravity wave momentum flux estimation using hybrid Doppler interferometry

    Science.gov (United States)

    Spargo, Andrew J.; Reid, Iain M.; MacKinnon, Andrew D.; Holdsworth, David A.

    2017-06-01

    Mesospheric gravity wave (GW) momentum flux estimates using data from multibeam Buckland Park MF radar (34.6° S, 138.5° E) experiments (conducted from July 1997 to June 1998) are presented. On transmission, five Doppler beams were symmetrically steered about the zenith (one zenith beam and four off-zenith beams in the cardinal directions). The received beams were analysed with hybrid Doppler interferometry (HDI) (Holdsworth and Reid, 1998), principally to determine the radial velocities of the effective scattering centres illuminated by the radar. The methodology of Thorsen et al. (1997), later re-introduced by Hocking (2005) and since extensively applied to meteor radar returns, was used to estimate components of Reynolds stress due to propagating GWs and/or turbulence in the radar resolution volume. Physically reasonable momentum flux estimates are derived from the Reynolds stress components, which are also verified using a simple radar model incorporating GW-induced wind perturbations. On the basis of these results, we recommend the intercomparison of momentum flux estimates between co-located meteor radars and vertical-beam interferometric MF radars. It is envisaged that such intercomparisons will assist with the clarification of recent concerns (e.g. Vincent et al., 2010) of the accuracy of the meteor radar technique.

  8. Correction of Doppler broadening of {gamma}-ray lines induced by particle emission in heavy-ion induced fusion-evaporation reactions

    Energy Technology Data Exchange (ETDEWEB)

    Nyberg, J; Seweryniak, D; Fahlander, C; Insua-Cao, P [Uppsala Univ. (Sweden). Dept. of Radiation Sciences; Johnson, A; Cederwall, B [Manne Siegbahn Inst. of Physics, Stockholm (Sweden); [Royal Inst. of Tech., Stockholm (Sweden); Adamides, E; Piiparinen, M [National Centre for Scientific Research, Ag. Paraskevi, Attiki (Greece); Atac, A; Norlin, L O [Niels Bohr Inst., Copenhagen (Denmark); Ideguchi, E; Mitarai, S [Kyushu Univ., Fukuoka (Japan). Dept. of Physics; Julin, R; Juutinen, S; Tormanen, S; Virtanen, A [Jyvaeskylae Univ. (Finland). Dept. of Physics; Karczmarczyk, W; Kownacki, J [Warsaw Univ. (Poland); Schubart, R [Hahn-Meitner-Institut Berlin GmbH (Germany)

    1992-08-01

    The effect of particle emission on the peak shape of {gamma}-ray lines have been investigated using the NORDBALL detector system. By detecting neutrons, protons and {alpha} particles emitted in the {sup 32}S (95 MeV) + {sup 27}Al reaction, the energy and direction of emission of the residual nuclei could be determined and subsequently used for an event-by -event Doppler correction of the detected {gamma} rays. Extensive Monte Carlo simulations were performed to study how the different Doppler phenomena influence the peak shape and in particular which particle detector properties are important for the Doppler correction. (author). 2 refs., 1 tab., 4 figs.

  9. Burst Format Design for Optimum Joint Estimation of Doppler-Shift and Doppler-Rate in Packet Satellite Communications

    Directory of Open Access Journals (Sweden)

    Luca Giugno

    2007-05-01

    Full Text Available This paper considers the problem of optimizing the burst format of packet transmission to perform enhanced-accuracy estimation of Doppler-shift and Doppler-rate of the carrier of the received signal, due to relative motion between the transmitter and the receiver. Two novel burst formats that minimize the Doppler-shift and the Doppler-rate Cramér-Rao bounds (CRBs for the joint estimation of carrier phase/Doppler-shift and of the Doppler-rate are derived, and a data-aided (DA estimation algorithm suitable for each optimal burst format is presented. Performance of the newly derived estimators is evaluated by analysis and by simulation, showing that such algorithms attain their relevant CRBs with very low complexity, so that they can be directly embedded into new-generation digital modems for satellite communications at low SNR.

  10. Patient-exposure data for doppler ultrasound

    International Nuclear Information System (INIS)

    Stewart, H.F.; Silvis, P.X.; Smith, S.W.

    1986-01-01

    In recent years ultrasound imaging and Doppler blood flow measurements have become important tools for use in diagnostic medicine. Commercial pulse-echo imaging equipment was first introduced into commerce in 1963. The first commercial continuous wave Doppler unit was introduced to the marketplace in 1966. As equipment improved and applications developed, the industry experienced rapid growth in the 1970s. One of the more recent growth areas in the application of diagnostic ultrasound has been the use of pulsed Doppler equipment for cardiac applications. Prior to 1976, some continuous wave Doppler ultrasound was used for cardiovascular diagnosis. However, only a single manufacturer marketed a pulsed Doppler clinical instrument for cardiac or peripheral vascular diagnosis. Currently, many continuous wave and pulsed Doppler instruments are commercially available for both peripheral vascular and cardiac diagnosis. This chapter (1) briefly reviews current safety guidelines, regulations, and recommendations for diagnostic ultrasound; (2) discusses the patient-exposure intensities associated with Doppler ultrasound medical equipment and compare these levels of exposure with intensities from other medical ultrasound devices; and (3) considers some of the current information as it relates to the safety of diagnostic ultrasound

  11. Doppler tomography in fusion plasmas and astrophysics

    DEFF Research Database (Denmark)

    Salewski, Mirko; Geiger, B.; Heidbrink, W. W.

    2015-01-01

    Doppler tomography is a well-known method in astrophysics to image the accretion flow, often in the shape of thin discs, in compact binary stars. As accretion discs rotate, all emitted line radiation is Doppler-shifted. In fast-ion Dα (FIDA) spectroscopy measurements in magnetically confined plasma......, the Dα-photons are likewise Doppler-shifted ultimately due to gyration of the fast ions. In either case, spectra of Doppler-shifted line emission are sensitive to the velocity distribution of the emitters. Astrophysical Doppler tomography has lead to images of accretion discs of binaries revealing bright...... and limits, analogies and differences in astrophysical and fusion plasma Doppler tomography and what can be learned by comparison of these applications....

  12. Doppler-guided retrograde catheterization system

    Science.gov (United States)

    Frazin, Leon J.; Vonesh, Michael J.; Chandran, Krishnan B.; Khasho, Fouad; Lanza, George M.; Talano, James V.; McPherson, David D.

    1991-05-01

    The purpose of this study was to investigate a Doppler guided catheterization system as an adjunctive or alternative methodology to overcome the disadvantages of left heart catheterization and angiography. These disadvantages include the biological effects of radiation and the toxic and volume effects of iodine contrast. Doppler retrograde guidance uses a 20 MHz circular pulsed Doppler crystal incorporated into the tip of a triple lumen multipurpose catheter and is advanced retrogradely using the directional flow information provided by the Doppler waveform. The velocity detection limits are either 1 m/second or 4 m/second depending upon the instrumentation. In a physiologic flow model of the human aortic arch, multiple data points revealed a positive wave form when flow was traveling toward the catheter tip indicating proper alignment for retrograde advancement. There was a negative wave form when flow was traveling away from the catheter tip if the catheter was in a branch or bent upon itself indicating improper catheter tip position for retrograde advancement. In a series of six dogs, the catheter was able to be accurately advanced from the femoral artery to the left ventricular chamber under Doppler signal guidance without the use of x-ray. The potential applications of a Doppler guided retrograde catheterization system include decreasing time requirements and allowing safer catheter guidance in patients with atherosclerotic vascular disease and suspected aortic dissection. The Doppler system may allow left ventricular pressure monitoring in the intensive care unit without the need for x-ray and it may allow left sided contrast echocardiography. With pulse velocity detection limits of 4 m/second, this system may allow catheter direction and passage into the aortic root and left ventricle in patients with aortic stenosis. A modification of the Doppler catheter may include transponder technology which would allow precise catheter tip localization once the

  13. Doppler-Zeeman mapping of the magnetic CP star HD 215441

    Science.gov (United States)

    Khokhlova, V. L.; Vasilchenko, D. V.; Stepanov, V. V.; Tsymbal, V. V.

    1997-07-01

    The method of Vasilchenko et al. (1996) is used to obtain a Doppler-Zeeman map of the magnetic CP star HD 215441. The magnetic field is approximated by a magnetic dipole that is arbitrarily shifted from the star center. The solution of the inverse problem yields the dipole parameters and the maps of Si, Ti, Cr, and Fe abundance anomalies; the coordinates of local magnetic vectors on the star surface are computed. A comparison of the distribution of abundance anomalies and the magnetic-field configuration reveals that in the region where the magnetic-field lines are vertical (near the magnetic pole), Si, Ti and Cr are highly deficient, while the Fe enhancement is strongest. In the regions where the magnetic-field lines are horizontal (near the magnetic equator), Si, Ti and Cr show the greatest overabundance. In these regions, the Fe abundance is also slightly enhanced and exhibits, as it were, a secondary maximum. The factors that limit the accuracy of Doppler-Zeeman mapping are reviewed.

  14. Color doppler imaging of subclavian steal phenomenon

    International Nuclear Information System (INIS)

    Cho, Nari Ya; Chung, Tae Sub; Kim, Jai Keun

    1997-01-01

    To evaluate the characteristic color doppler imaging of vertebral artery flow in the subclavian steal phenomenon. The study group consisted of eight patients with reversed vertebral artery flow proved by color Doppler imaging. We classified this flow into two groups:(1) complete reversal;(2) partial reversal, as shown by Doppler velocity waveform. Vertebral angiography was performed in six of eight patients;color Doppler imaging and angiographic findings were compared. On color Doppler imaging, all eight cases with reversed vertebral artery flow showed no signal at the proximal subclavian or brachiocephalic artery. We confirmed shunting of six cases by performing angiography from the contralateral vertebral and basilar artery to the ipsilateral vertebral artery. On the Doppler spectrum, six cases showed complete reversal and two partial reversal. On angiography, one partial reversal case showed complete occlusion of the subclavian artery with abundant collateral circulation of muscular branches of the vertebral artery. On color Doppler imaging, a reversed vertebral artery suggests the subclavian steal phenomenon. In particular, partial reversal waveform may reflect collateral circulation

  15. Radar micro-doppler signatures processing and applications

    CERN Document Server

    Chen, Victor C; Miceli, William J

    2014-01-01

    Radar Micro-Doppler Signatures: Processing and applications concentrates on the processing and application of radar micro-Doppler signatures in real world situations, providing readers with a good working knowledge on a variety of applications of radar micro-Doppler signatures.

  16. Color doppler sonography in thickened gallbladder wall

    International Nuclear Information System (INIS)

    Han, Sang Suk; Choi, Seok Jin; Seo, Chang Hae; Eun, Choong Ki

    1996-01-01

    The thickening of the gallbladder wall is a valuable finding for the diagnosis of cholecystitis, but may be seen in non-cholecystic disease as well as in acute or chronic cholecystitis. The purpose of this study is to determine the value of color Doppler sonography in differentiating the causes of thickened gallbladder wall. Ninety eight patients with thickened gallbladder wall(more than 3mm) which was not due to gallbladder cancer were prospectively evaluated with color Doppler sonography. Sixty-six cases, confirmed by pathologic reports and clinical records, were analyzed for correlation between thickened gallbladder wall and color flow signal according to the underlying causes. Of the 66 patients, 28 cases were cholecystitis and 38 cases had non-cholecystic causes such as liver cirrhosis, ascites, hepatitis, pancreatitis, renal failure, and hypoalbuminemia. Of the 28 patients with cholecystitis(12 acute, 16 chronic), 23(82%) had color Doppler flow signals in the thickened gallbladder wall. Of the 38 patients with non-cholecystic causes, eight(21%) had color Doppler flow signals. There was a statistically significant difference of color Doppler flow signals between the cholecystitis and non-cholecystic groups(p=0.0001). No significant difference of color Doppler flow signals was found between cases of acute and chronic cholecystitis. Of the 23 patients with color Doppler flow signals in 28 cases of cholecystitis, 18(78.3%) showed a linear pattern and five(21.7%) showed a spotty pattern. Of the eight patients with color Doppler flow signals in the 38 non-cholecystic cases, four(50%) showed a linear pattern and four(50%) showed a spotty pattern. In cholecystitis, a linear color Doppler flow signal pattern is a much more frequent finding than a spotty pattern. Color Doppler sonography is a useful and adequate method for determining whether a thickened gallbladder wall is the result of cholecystitis or has non-cholecystic causes

  17. Pulse Doppler radar

    CERN Document Server

    Alabaster, Clive

    2012-01-01

    This book is a practitioner's guide to all aspects of pulse Doppler radar. It concentrates on airborne military radar systems since they are the most used, most complex, and most interesting of the pulse Doppler radars; however, ground-based and non-military systems are also included. It covers the fundamental science, signal processing, hardware issues, systems design and case studies of typical systems. It will be a useful resource for engineers of all types (hardware, software and systems), academics, post-graduate students, scientists in radar and radar electronic warfare sectors and milit

  18. CONSTRAINING HIGH-SPEED WINDS IN EXOPLANET ATMOSPHERES THROUGH OBSERVATIONS OF ANOMALOUS DOPPLER SHIFTS DURING TRANSIT

    International Nuclear Information System (INIS)

    Miller-Ricci Kempton, Eliza; Rauscher, Emily

    2012-01-01

    Three-dimensional (3D) dynamical models of hot Jupiter atmospheres predict very strong wind speeds. For tidally locked hot Jupiters, winds at high altitude in the planet's atmosphere advect heat from the day side to the cooler night side of the planet. Net wind speeds on the order of 1-10 km s –1 directed towards the night side of the planet are predicted at mbar pressures, which is the approximate pressure level probed by transmission spectroscopy. These winds should result in an observed blueshift of spectral lines in transmission on the order of the wind speed. Indeed, Snellen et al. recently observed a 2 ± 1 km s –1 blueshift of CO transmission features for HD 209458b, which has been interpreted as a detection of the day-to-night (substellar to anti-stellar) winds that have been predicted by 3D atmospheric dynamics modeling. Here, we present the results of a coupled 3D atmospheric dynamics and transmission spectrum model, which predicts the Doppler-shifted spectrum of a hot Jupiter during transit resulting from winds in the planet's atmosphere. We explore four different models for the hot Jupiter atmosphere using different prescriptions for atmospheric drag via interaction with planetary magnetic fields. We find that models with no magnetic drag produce net Doppler blueshifts in the transmission spectrum of ∼2 km s –1 and that lower Doppler shifts of ∼1 km s –1 are found for the higher drag cases, results consistent with—but not yet strongly constrained by—the Snellen et al. measurement. We additionally explore the possibility of recovering the average terminator wind speed as a function of altitude by measuring Doppler shifts of individual spectral lines and spatially resolving wind speeds across the leading and trailing terminators during ingress and egress.

  19. Impacto do ecocardiograma transesofágico intraoperatório na mortalidade em cirurgia de revascularização do miocárdio com circulação extracorpórea

    Directory of Open Access Journals (Sweden)

    Marcello Fonseca Salgado Filho

    Full Text Available OBJETIVO: avaliar as taxas de mortalidade e morbidade de doentes submetidos à revascularização do miocárdio (RVM com circulação extracorpórea (CEC que utilizaram rotineiramente o ecocardiograma transesofágico intraoperatório (ETEio. MÉTODOS: estudo retrospectivo, observacional com avaliação de prontuários de 360 doentes no período entre abril de 2010 a abril de 2012. Foram analisados: idade, peso, altura sexo, EUROscore, diabete melito, fração de ejeção e artérias acometidas. Os desfechos foram compilados no intra e no pós-operatório (infarto do miocárdio, acidente vascular cerebral, disfunção renal, hemodiálise, fibrilação atrial, tempo de internação no centro de tratamento intensivo. RESULTADOS: foram incluídos 53 doentes, com 27 recebendo a monitoração. Foram excluídos 307 porque não foram operados pela mesma equipe cirúrgica. Os dois grupos foram homogêneos quanto a idade, peso e sexo, porém, a fração ejeção foi menor no grupo que recebeu o ecotransesofágico (G ETEio: 56,3%; G Não ETEio: 65,9% ± 11; p=0,01. Nos doentes em que não foi utilizado o ETEio, a mortalidade foi maior (G ETEio: 0% e G Não ETEio: 7,6%; p=0,01. Não houve diferença significativa entre os grupos quanto à incidência de acidente vascular encefálico, infarto agudo do miocárdio, fibrilação atrial aguda e lesão renal. CONCLUSÃO: a utilização do ecocardiograma transesofágico intraoperatório em pacientes submetidos à revascularização do miocárdio, com circulação extracorpórea, diminuiu a mortalidade perioperatória; orientou quanto a utilização dos fármacos inotrópicos e vasodilatadores e contribuiu para uma melhor evolução dos doentes.

  20. The medical Doppler in hand surgery: its scientific basis, applications, and the history of its namesake, Christian Johann Doppler.

    Science.gov (United States)

    Ghori, Ahmer K; Chung, Kevin C

    2007-12-01

    The word Doppler is used synonymously in hand surgery for evaluating patency of vascular structures; however, the science and history behind the Doppler effect are not as well-known. We will present the theories behind the Doppler effect and the history of the person who made this discovery.

  1. Noncoherent Doppler tracking: first flight results

    Science.gov (United States)

    DeBoy, Christopher C.; Robert Jensen, J.; Asher, Mark S.

    2005-01-01

    Noncoherent Doppler tracking has been devised as a means to achieve highly accurate, two-way Doppler measurements with a simple, transceiver-based communications system. This technique has been flown as an experiment on the Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics (TIMED) spacecraft, (launched 7 December 2001), as the operational technique for Doppler tracking on CONTOUR, and is baselined on several future deep space missions at JHU/APL. This paper reports on initial results from a series of successful tests of this technique between the TIMED spacecraft and NASA ground stations in the Deep Space Network. It also examines the advantages that noncoherent Doppler tracking and a transceiver-based system may offer to small satellite systems, including reduced cost, mass, and power.

  2. Anomalous Doppler effects in bulk phononic crystal

    International Nuclear Information System (INIS)

    Cai Feiyan; He Zhaojian; Zhang Anqi; Ding Yiqun; Liu Zhengyou

    2010-01-01

    Doppler effects in simple cubic phononic crystal are studied theoretically and numerically. In addition to observing Doppler shifts from a moving source's frequencies inside the gap, we find that Doppler shifts can be multi-order, anisotropic, and the dominant order of shift depends on the band index that the source's frequency is in.

  3. Detection of Fast Moving and Accelerating Targets Compensating Range and Doppler Migration

    Science.gov (United States)

    2014-06-01

    TR–2978 UNCLASSIFIED the chirp bandwidth is changed from pulse to pulse to realise the range migration com- pensation. Also, Dai et. al. [11] proposed...injected at different closing velocities and acceleration values . Figure 1(a) shows the range-Doppler map of a non-accelarating target moving at 100 knots...increase the noise floor. Hence, consideration must be given to establish a criteria for the combination processing to achieve a net SNR improvement for a

  4. Positron annihilation studies of icosahedral quasicrystals and their approximants in the Al-Cu-Ru-(Si) alloy systems

    International Nuclear Information System (INIS)

    Uchiyama, H; Takahashi, T; Arinuma, K; Sato, K; Kanazawa, I; Hamada, E; Suzuki, T; Kirihara, K; Kimura, K

    2004-01-01

    The positron lifetimes for the icosahedral quasicrystal Al 62.4 Cu 25.4 Ru 12.2 and its cubic approximants (1/ 1-Al 58 Cu 31.5 Ru 10.5 , 1/ 1-Al 68 Cu 7 Ru 17 Si 8 , and 1/0-Al 55 Cu 15 Ru 20 Si 10 ), two-detector coincident Doppler broadening for the icosahedral quasicrystal Al 62.4 Cu 25.4 Ru 12.2 and its 1/ 1-Al 68 Cu 7 Ru 17 Si 8 cubic approximant, and the Doppler broadening obtained by making use of a slow positron beam for the 1/ 1-Al 58 Cu 31.5 Ru 10.5 cubic approximant have been measured. Structurally intrinsic trapping sites giving rise to saturation trapping were detected by lifetime measurements. The chemical environments of the trapping sites in the icosahedral quasicrystal Al 62.4 Cu 25.4 Ru 12.2 and the 1/ 1-Al 68 Cu 7 Ru 17 Si 8 cubic approximant were determined by coincident Doppler broadening techniques to be dominantly surrounded by Al atoms. The positron diffusion length in the 1/ 1-Al 58 Cu 31.5 Ru 10.5 cubic approximant derived from the measured S parameter measured by means of a slow positron beam was ∼ 180 A, which is clearly too short, probably due to the high concentration of trapping sites as described above. The atomic structures of the icosahedral quasicrystal Al 62.4 Cu 25.4 Ru 12.2 and its variety of approximants are discussed and compared to the present proposed model

  5. Estimating the Doppler centroid of SAR data

    DEFF Research Database (Denmark)

    Madsen, Søren Nørvang

    1989-01-01

    attractive properties. An evaluation based on an existing SEASAT processor is reported. The time-domain algorithms are shown to be extremely efficient with respect to requirements on calculations and memory, and hence they are well suited to real-time systems where the Doppler estimation is based on raw SAR......After reviewing frequency-domain techniques for estimating the Doppler centroid of synthetic-aperture radar (SAR) data, the author describes a time-domain method and highlights its advantages. In particular, a nonlinear time-domain algorithm called the sign-Doppler estimator (SDE) is shown to have...... data. For offline processors where the Doppler estimation is performed on processed data, which removes the problem of partial coverage of bright targets, the ΔE estimator and the CDE (correlation Doppler estimator) algorithm give similar performance. However, for nonhomogeneous scenes it is found...

  6. Power and color Doppler ultrasound settings for inflammatory flow

    DEFF Research Database (Denmark)

    Torp-Pedersen, Søren; Christensen, Robin; Szkudlarek, Marcin

    2015-01-01

    OBJECTIVE: To determine how settings for power and color Doppler ultrasound sensitivity vary on different high- and intermediate-range ultrasound machines and to evaluate the impact of these changes on Doppler scoring of inflamed joints. METHODS: Six different types of ultrasound machines were used....... On each machine, the factory setting for superficial musculoskeletal scanning was used unchanged for both color and power Doppler modalities. The settings were then adjusted for increased Doppler sensitivity, and these settings were designated study settings. Eleven patients with rheumatoid arthritis (RA......) with wrist involvement were scanned on the 6 machines, each with 4 settings, generating 264 Doppler images for scoring and color quantification. Doppler sensitivity was measured with a quantitative assessment of Doppler activity: color fraction. Higher color fraction indicated higher sensitivity. RESULTS...

  7. Evolution of voids in Al+-implanted ZnO probed by a slow positron beam

    International Nuclear Information System (INIS)

    Chen, Z.Q.; Maekawa, M.; Yamamoto, S.; Kawasuso, A.; Yuan, X.L.; Sekiguchi, T.; Suzuki, R.; Ohdaira, T.

    2004-01-01

    Undoped ZnO single crystals were implanted with aluminum ions up to a dose of 10 15 Al + /cm 2 . Vacancy defects in the implanted layers were detected using positron lifetime and Doppler broadening measurements with slow positron beams. It shows that vacancy clusters, which are close to the size of V 8 , are generated by implantation. Postimplantation annealing shows that the Doppler broadening S parameter increases in the temperature range from 200 deg. C to 600 deg. C suggesting further agglomeration of vacancy clusters to voids. Detailed analyses of Doppler broadening spectra show formation of positronium after 600 deg. C annealing of the implanted samples with doses higher than 10 14 Al + /cm 2 . Positron lifetime measurements further suggest that the void diameter is about 0.8 nm. The voids disappear and the vacancy concentration reaches the detection limit after annealing at 600-900 deg. C. Hall measurement shows that the implanted Al + ions are fully activated with improved carrier mobility after final annealing. Cathodoluminescence measurements show that the ultraviolet luminescence is much stronger than the unimplanted state. These findings also suggest that the electrical and optical properties of ZnO become much better by Al + implantation and subsequent annealing

  8. TCSP ER-2 DOPPLER RADAR (EDOP) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The TCSP ER-2 DOPPLER RADAR (EDOP) dataset was collected by the ER-2 Doppler radar (EDOP), which is an X-band (9.6 GHz) Doppler radar mounted in the nose of the ER-2...

  9. CAMEX-4 ER-2 DOPPLER RADAR V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The CAMEX-4 ER-2 Doppler Radar dataset was collected by the ER-2 Doppler radar (EDOP), which is an X-band (9.6 GHz) Doppler radar mounted in the nose of ER-2. The...

  10. Defect investigations of micron sized precipitates in Al alloys

    Science.gov (United States)

    Klobes, B.; Korff, B.; Balarisi, O.; Eich, P.; Haaks, M.; Kohlbach, I.; Maier, K.; Sottong, R.; Staab, T. E. M.

    2011-01-01

    A lot of light aluminium alloys achieve their favourable mechanical properties, especially their high strength, due to precipitation of alloying elements. This class of age hardenable Al alloys includes technologically important systems such as e.g. Al-Mg-Si or Al-Cu. During ageing different precipitates are formed according to a specific precipitation sequence, which is always directed onto the corresponding intermetallic equilibrium phase. Probing the defect state of individual precipitates requires high spatial resolution as well as high chemical sensitivity. Both can be achieved using the finely focused positron beam provided by the Bonn Positron Microprobe (BPM) [1] in combination with the High Momentum Analysis (HMA) [2]. Employing the BPM, structures in the micron range can be probed by means of the spectroscopy of the Doppler broadening of annihilation radiation (DBAR). On the basis of these prerequisites single precipitates of intermetallic phases in Al-Mg-Si and Al-Cu, i.e. Mg2Si and Al2Cu, were probed. A detailed interpretation of these measurements necessarily relies on theoretical calculations of the DBAR of possible annihilation sites. These were performed employing the DOPPLER program. However, previous to the DBAR calculation the structures, which partly contain vacancies, were relaxed using the ab-initio code SIESTA, i.e. the atomic positions in presence of a vacancy were recalculated.

  11. Defect investigations of micron sized precipitates in Al alloys

    Energy Technology Data Exchange (ETDEWEB)

    Klobes, B; Korff, B; Balarisi, O; Eich, P; Haaks, M; Kohlbach, I; Maier, K; Sottong, R [Helmholtz-Institut fuer Strahlen- und Kernphysik, Nussallee 14-16, D-53115 Bonn (Germany); Staab, T E M, E-mail: klobes@hiskp.uni-bonn.de [Fraunhofer ISC, Neunerplatz 2, D-97082 Wuerzburg (Germany)

    2011-01-01

    A lot of light aluminium alloys achieve their favourable mechanical properties, especially their high strength, due to precipitation of alloying elements. This class of age hardenable Al alloys includes technologically important systems such as e.g. Al-Mg-Si or Al-Cu. During ageing different precipitates are formed according to a specific precipitation sequence, which is always directed onto the corresponding intermetallic equilibrium phase. Probing the defect state of individual precipitates requires high spatial resolution as well as high chemical sensitivity. Both can be achieved using the finely focused positron beam provided by the Bonn Positron Microprobe (BPM) in combination with the High Momentum Analysis (HMA). Employing the BPM, structures in the micron range can be probed by means of the spectroscopy of the Doppler broadening of annihilation radiation (DBAR). On the basis of these prerequisites single precipitates of intermetallic phases in Al-Mg-Si and Al-Cu, i.e. Mg{sub 2}Si and Al{sub 2}Cu, were probed. A detailed interpretation of these measurements necessarily relies on theoretical calculations of the DBAR of possible annihilation sites. These were performed employing the DOPPLER program. However, previous to the DBAR calculation the structures, which partly contain vacancies, were relaxed using the ab-initio code SIESTA, i.e. the atomic positions in presence of a vacancy were recalculated.

  12. Direct Doppler auscultation of the carotid arteries

    International Nuclear Information System (INIS)

    Nix, L.

    1984-01-01

    The results of the carotid Doppler examinations and contrast arteriograms are presented. The overall sensitivity of the carotid Doppler examinations in detecting severe stenosis or occlusion of the carotid artery was 92%. The Doppler studies correctly differentiated these two conditions in 84% of the diseased vessels. In carotid arteries with stenosis greater than or equal to 50%, the sensitivity of the Doppler examinations was 90%, and these studies suggested stenosis in all but two of the 36 abnormal examinations. In two patent carotids with greater than 90% stenosis, a signal could not be elicited, presumably because of the low blood flow through the severely stenotic segment

  13. Recommendations for terminology and display for doppler echocardiography

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    Doppler echocardiography has recently emerged as a major noninvasive technique with many applications in cardiology. To a large extent, this has been based upon a combination of clinical and engineering advances which now make possible the use of quantitative Doppler echocardiography in combination with two-dimensional imaging for measurement of volume flows, transvalve gradients, and other physiologic flow parameters which reflect cardiac function. It was the purpose of this Committee to provide a glossary of terms which could be used in standard fashion for papers and discussions related to Doppler echocardiography. As part of its task, the Committee also undertook an attempt to recommend a standard for display of Doppler information which would be useful, both for manufacturers and for clinicians. The document, therefore, includes: Section I, the Committee's recommendations for Doppler display. Section II, the glossary of Doppler terms, related to engineering and to clinical applications

  14. Cognitive dysfunction in congestive heart failure: transcranial Doppler evidence of microembolic etiology Disfunção cognitiva na insuficiência cardíaca congestiva: evidência de etiologia microembólica ao Doppler transcraniano

    Directory of Open Access Journals (Sweden)

    Pedro A.P. Jesus

    2006-06-01

    Full Text Available Cognitive symptoms are common in patients with congestive heart failure (CHF and are usually attributed to low cerebral blood flow. In the present study, we aimed to evaluate global cognitive function (Mini Mental State Exam MMSE in relation to both cardiac function (evaluated by echocardiogram and cerebrovascular hemodynamics (evaluated by transcranial Doppler TCD in CHF patients. In 83 patients studied, no correlation was found between echocardiographic parameters and MMSE scores. In contrast, a significant correlation was found between right middle cerebral artery (RMCA mean flow velocity and MMSE score (r=0.231 p=0.039, as well as between RMCA pulsatility index and MMSE score (r s= -0.292 p=0.015. After excluding patients with a previous history of stroke, only RMCA pulsatility index correlated with MMSE score (r s=-0,314 p=0,007. The relationship between high cerebrovascular resistance and worse cognitive scores suggest that microembolism may be responsible for a significant proportion of cognitive symptoms in CHF patients.Sintomas cognitivos são comuns em pacientes com insuficiência cardíaca congestiva (ICC e são geralmente atribuídos a um regime de baixo fluxo sanguíneo cerebral. Neste estudo, objetivamos avaliar a função cognitiva global (Mini Exame do Estado Mental MEEM em pacientes com ICC e sua relação com o grau de disfunção cardíaca (avaliada pelo ecocardiograma e a hemodinâmica cerebral (avaliada pelo Doppler transcraniano DTC. Em 83 pacientes estudados, nenhuma correlação foi encontrada entre a pontuação no MEEM e parâmetros ecocardiográficos. Em contraste, uma correlação significativa foi encontrada entre a velocidade média na artéria cerebral média direita (ACMD e a pontuação no MEEM (r=0,231 p=0,039, assim como entre o índice de pulsatilidade na ACMD e a pontuação no MEEM (r s=-0,292 p=0,015. Após excluir pacientes com histórico prévio de acidente vascular encefálico, somente o índice de

  15. High-Frame-Rate Power Doppler Ultrasound Is More Sensitive than Conventional Power Doppler in Detecting Rheumatic Vascularisation

    NARCIS (Netherlands)

    M. van der Ven (Myrthe); J.J. Luime (Jolanda); van der Velden, L.L. (Levinia L.); J.G. Bosch (Hans); J.M.W. Hazes (Mieke); H.J. Vos (Rik)

    2016-01-01

    textabstractEarly recognition of joint inflammation will increase treatment efficacy in rheumatoid arthritis (RA). Yet, conventional power Doppler (PD) ultrasound might not be sufficiently sensitive to detect minor inflammation. We investigated the sensitivity of high-frame rate Doppler, combined

  16. Power doppler 'blanching' after the application of transducer pressure

    International Nuclear Information System (INIS)

    Joshua, F.; Edmonds, J.; Lassere, M.; De Carle, R.; Rayment, M.; Bryant, C.; Shnier, R.

    2005-01-01

    The aim of this study was to determine if transducer pressure modifies power Doppler assessments of rheumatoid arthritis synovium at the metacarpophalangeal joints and metatarsophalangeal joints. Five rheumatoid arthritis patients of varying degrees of 'disease activity' and damage were assessed with power Doppler ultrasound scanning of the dominant hand second to fifth metacarpophalangeal joints. Two rheumatoid arthritis patients had their dominant foot first to fifth metatarsophalangeal joints assessed with power Doppler ultrasound. Ultrasonography was performed with a high frequency transducer (14 MHz) with a colour mode frequency of 10 Mhz, and a standard colour box and gain. In the joint that showed the highest power Doppler signal, an image was made. A further image was taken after transducer pressure was applied. In all patients, there was increased flow to at least one joint. After pressure was applied, power Doppler signal intensity markedly reduced in all images and in some there was no recordable power Doppler signal. Increased transducer pressure can result in a marked reduction or obliteration in power Doppler signal. This power Doppler 'blanching' shows the need for further studies to evaluate sources of error and standardization before power Doppler ultrasound becomes a routine measure of 'disease activity' in rheumatoid arthritis. Copyright (2005) Blackwell Science Pty Ltd

  17. Development of the doppler electron velocimeter: theory.

    Energy Technology Data Exchange (ETDEWEB)

    Reu, Phillip L.

    2007-03-01

    Measurement of dynamic events at the nano-scale is currently impossible. This paper presents the theoretical underpinnings of a method for making these measurements using electron microscopes. Building on the work of Moellenstedt and Lichte who demonstrated Doppler shifting of an electron beam with a moving electron mirror, further work is proposed to perfect and utilize this concept in dynamic measurements. Specifically, using the concept of ''fringe-counting'' with the current principles of transmission electron holography, an extension of these methods to dynamic measurements is proposed. A presentation of the theory of Doppler electron wave shifting is given, starting from the development of the de Broglie wave, up through the equations describing interference effects and Doppler shifting in electron waves. A mathematical demonstration that Doppler shifting is identical to the conceptually easier to understand idea of counting moving fringes is given by analogy to optical interferometry. Finally, potential developmental experiments and uses of a Doppler electron microscope are discussed.

  18. Re-Normalization Method of Doppler Lidar Signal for Error Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Park, Nakgyu; Baik, Sunghoon; Park, Seungkyu; Kim, Donglyul [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Dukhyeon [Hanbat National Univ., Daejeon (Korea, Republic of)

    2014-05-15

    In this paper, we presented a re-normalization method for the fluctuations of Doppler signals from the various noises mainly due to the frequency locking error for a Doppler lidar system. For the Doppler lidar system, we used an injection-seeded pulsed Nd:YAG laser as the transmitter and an iodine filter as the Doppler frequency discriminator. For the Doppler frequency shift measurement, the transmission ratio using the injection-seeded laser is locked to stabilize the frequency. If the frequency locking system is not perfect, the Doppler signal has some error due to the frequency locking error. The re-normalization process of the Doppler signals was performed to reduce this error using an additional laser beam to an Iodine cell. We confirmed that the renormalized Doppler signal shows the stable experimental data much more than that of the averaged Doppler signal using our calibration method, the reduced standard deviation was 4.838 Χ 10{sup -3}.

  19. Maximisation of the Doppler effect in thermal reactors

    International Nuclear Information System (INIS)

    Bende, E.E.

    1998-03-01

    Increase of the fuel temperature in a nuclear reactor leads, or can lead, to (1) A Doppler broadening of the resonances of the nuclides in the fuel; (2) An expansion of the fuel; and (3) A shift of the Maxwellian part of the spectrum to higher energies. These processes together introduce a certain amount of reactivity, which can be expressed in the so-called fuel temperature reactivity coefficient. The reactivity effect of the third process is very small, because the Maxwell spectrum is to a major extent determined by the moderator temperature. Moreover, the reactivity effect due to an expansion of the fuel is small too, for most thermal systems. When the second and third processes can be neglected, the fuel temperature reactivity effect is fully determined by the Doppler effect. The fuel temperature reactivity coefficient is then called the Doppler coefficient of reactivity. The Doppler broadening of the resonances causes an increase of resonance absorption, due to a decrease of self-shielding. The competition between resonance fission at the one hand and resonance capture at the other hand determines the sign and magnitude of the reactivity induced by an increase of the fuel temperature. In well-designed nuclear reactors the Doppler effect due to resonance capture by fertile nuclides exceeds the Doppler effect due to resonance fission, which implies that an increase of the fuel temperature causes a negative reactivity effect and a correspondingly negative Doppler coefficient. Since the Doppler effect is a prompt effect, occurring simultaneously with the dissipation of kinetic energy of the fission products into temperature, it is very important in the study of rapid power transients. In this report, the Doppler coefficient of reactivity is defined in chapter 2. Chapter 3 discusses the geometry of the unit-cell for which the calculations are performed and describes the fuel types that have been investigated. In chapter 4 the 'Doppler efficiency' is introduced and

  20. Is Doppler ultrasound useful for evaluating gestational trophoblastic disease?

    Directory of Open Access Journals (Sweden)

    Lawrence H. Lin

    Full Text Available Doppler ultrasound is a non-invasive method for evaluating vascularization and is widely used in clinical practice. Gestational trophoblastic neoplasia includes a group of highly vascularized malignancies derived from placental cells. This review summarizes data found in the literature regarding the applications of Doppler ultrasound in managing patients with gestational trophoblastic neoplasia. The PubMed/Medline, Web of Science, Cochrane and LILACS databases were searched for articles published in English until 2014 using the following keywords: “Gestational trophoblastic disease AND Ultrasonography, Doppler.” Twenty-eight articles met the inclusion criteria and were separated into the 4 following groups according to the aim of the study. (1 Doppler ultrasound does not seem to be capable of differentiating partial from complete moles, but it might be useful when evaluating pregnancies in which a complete mole coexists with a normal fetus. (2 There is controversy in the role of uterine artery Doppler velocimetry in the prediction of development of gestational trophoblastic neoplasia. (3 Doppler ultrasound is a useful tool in the diagnosis of gestational trophoblastic neoplasia because abnormal myometrial vascularization and lower uterine artery Doppler indices seem to be correlated with invasive disease. (4 Lower uterine artery Doppler indices in the diagnosis of gestational trophoblastic neoplasia are associated with methotrexate resistance and might play a role in prognosis. CONCLUSION: Several studies support the importance of Doppler ultrasound in the management of patients with gestational trophoblastic neoplasia, particularly the role of Doppler velocimetry in the prediction of trophoblastic neoplasia and the chemoresistance of trophoblastic tumors. Doppler findings should be used as ancillary tools, along with human chorionic gonadotropin assessment, in the diagnosis of gestational trophoblastic neoplasia.

  1. Is Doppler ultrasound useful for evaluating gestational trophoblastic disease?

    Science.gov (United States)

    Lin, Lawrence H; Bernardes, Lisandra S; Hase, Eliane A; Fushida, Koji; Francisco, Rossana P V

    2015-12-01

    Doppler ultrasound is a non-invasive method for evaluating vascularization and is widely used in clinical practice. Gestational trophoblastic neoplasia includes a group of highly vascularized malignancies derived from placental cells. This review summarizes data found in the literature regarding the applications of Doppler ultrasound in managing patients with gestational trophoblastic neoplasia. The PubMed/Medline, Web of Science, Cochrane and LILACS databases were searched for articles published in English until 2014 using the following keywords: "Gestational trophoblastic disease AND Ultrasonography, Doppler." Twenty-eight articles met the inclusion criteria and were separated into the 4 following groups according to the aim of the study. (1) Doppler ultrasound does not seem to be capable of differentiating partial from complete moles, but it might be useful when evaluating pregnancies in which a complete mole coexists with a normal fetus. (2) There is controversy in the role of uterine artery Doppler velocimetry in the prediction of development of gestational trophoblastic neoplasia. (3) Doppler ultrasound is a useful tool in the diagnosis of gestational trophoblastic neoplasia because abnormal myometrial vascularization and lower uterine artery Doppler indices seem to be correlated with invasive disease. (4) Lower uterine artery Doppler indices in the diagnosis of gestational trophoblastic neoplasia are associated with methotrexate resistance and might play a role in prognosis. Several studies support the importance of Doppler ultrasound in the management of patients with gestational trophoblastic neoplasia, particularly the role of Doppler velocimetry in the prediction of trophoblastic neoplasia and the chemoresistance of trophoblastic tumors. Doppler findings should be used as ancillary tools, along with human chorionic gonadotropin assessment, in the diagnosis of gestational trophoblastic neoplasia.

  2. Gamma-ray induced doppler broadening

    International Nuclear Information System (INIS)

    Robinson, S.J.

    1992-01-01

    The ultra high resolving power of the GAMS4 double-flat crystal spectrometer (M.S. Dewey et al Nucl. Instrum. Methods A 284 (1989) 151.) has been used to observe the Doppler broadening of gamma-rays emitted by nuclei recoiling at speeds as low as 10 -6 c. Such recoils may be induced by the previous emission of gamma-radiation following thermal neutron capture. If the population mechanism of an excited state is known (or can be approximated) and the slowing down mechanism can be modeled, then this technique can be used to extract the lifetime of excited nuclear states. The combination of this technique and the neutron capture reaction allows the study of states which cannot necessarily be accessed by other means. This has allowed the resolution of a number of long standing questions in low-spin nuclear structure. The basis of the technique is discussed and a number of examples given

  3. Preliminary simulation study of doppler reflectometry

    International Nuclear Information System (INIS)

    Ishii, Yuta; Hojo, Hitoshi; Yoshikawa, Masashi; Ichimura, Makoto; Haraguchi, Yusuke; Imai, Tsuyoshi; Mase, Atsushi

    2010-01-01

    A preliminary simulation study of Doppler reflectometry is performed. The simulations solve Maxwell's equations by a finite difference time domain (FDTD) code method in two dimensions. A moving corrugated metal target is used as a plasma cutoff layer to study the basic features of Doppler reflectometry. We examined the effects of the full width at half maximum (FWHM) of the electromagnetic waves and the corrugation depth of the metal target. Furthermore, the effect of a nonuniform plasma is studied using this FDTD analysis. The Doppler shift and velocity are compared with those obtained from FDTD analysis of a uniform plasma. (author)

  4. Doppler speedometer for micro-organisms

    International Nuclear Information System (INIS)

    Penkov, F.; Tuleushev, A.; Lisitsyn, V.; Kim, S.; Tuleushev, Yu.

    1996-01-01

    Objective of Investigations: Development and creation of the Doppler speedometer for micro-organisms which allows to evaluate, in a real temporal scale, variations in the state of water suspension of micro-organisms under the effect of chemical, physical and other external actions. Statement of the Problem The main problem is absence of reliable, accessible for users and simple, in view of application, Doppler speedometers for micro-organisms. Nevertheless, correlation Doppler spectrometry in the regime of heterodyning the supporting and cell-scattered laser radiation is welt known. The main idea is that the correlation function of photo-current pulses bears an information on the averages over the assembly of cell velocities. For solving the biological problems, construction of auto-correlation function in the real-time regime with the delay time values comprising, function in the real-time regime with the delay time values comprising, nearly, 100 me (10 khz) or higher is needed. Computers of high class manage this problem using but the program software. Due to this, one can simplify applications of the proposed techniques provided he creates the Doppler speedometer for micro-organism on a base of the P entium . Expected Result Manufactured operable mock-up of the Doppler speedometer for micro-organisms in a form of the auxiliary computer block which allows to receive an information, in the real time scale, on the results of external effects of various nature on the cell assembly in transparent medium with a small volume of the studied cell suspension

  5. De-Dopplerization of Acoustic Measurements

    Science.gov (United States)

    2017-08-10

    accurate measurement of aircraft location to resample the time signal to account for the compression and expansion of acoustic wavefronts. Correcting...AFRL-RH-WP-TR-2017-0043 DE-DOPPLERIZATION OF ACOUSTIC MEASUREMENTS Frank Mobley, PhD 711 HPW/RHCB Wright-Patterson AFB OH...TITLE AND SUBTITLE DE-DOPPLERIZATION OF ACOUSTIC MEASUREMENTS 5a. CONTRACT NUMBER In-House 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER

  6. Calculation of the Doppler broadening function using Fourier analysis;Calculo da funcao de alargamento Doppler utilizando analise de Fourier

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, Alessandro da Cruz

    2010-07-01

    An efficient and precise method for calculation of Doppler broadening function is very important to obtain average group microscopic cross sections, self shielding factors, resonance integrals and others reactor physics parameter. In this thesis two different methods for calculation of Doppler broadening function and interference term will be presented. The main method is based on a new integral form for Doppler broadening function {psi}(x,{zeta}) which gives a mathematical interpretation of the approximation proposed by Bethe and Placzek, as the convolution of the Lorentzian function with a Gaussian function. This interpretation besides leading to a new integral form for {psi}(x,{zeta}), enables to obtain a simple analytic solution for the Doppler broadening function. (author)

  7. Alergia ao leite de vaca: achados do ultrassom com Doppler colorido em neonatos com hematoquezia

    Directory of Open Access Journals (Sweden)

    Matias Epifanio

    2013-12-01

    Full Text Available OBJETIVO: o ultrassom (US tem sido uma importante ferramenta de diagnóstico para identificar várias causas de hemorragia gastrointestinal. Neonatos com alergia ao leite de vaca (ALV podem apresentar hematoquezia, e a confirmação do diagnóstico pode ser difícil. O objetivo deste estudo é descrever achados com ultrassom em escala de cinza e com Doppler colorido em pacientes com ALV. MÉTODOS: estudamos, retrospectivamente, 13 neonatos com ALV. Todos eles apresentaram hematoquezia severa e dor abdominal e foram submetidos a um estudo com US, com o diagnóstico de colite alérgica. O diagnóstico teve como base os achados clínicos, a recuperação após a dieta de exclusão do neonato ou da mãe, no caso de amamentação exclusiva, e o teste de provocação oral positivo. RESULTADOS: a idade média variou de um a seis meses (média = 3,53. Sete dos 13 neonatos (53,8% passaram novamente por ultrassonografia em escala de cinza e com Doppler colorido após a dieta de exclusão. Dentre eles, 12 dos 13 (92,3% mostraram anormalidades no US e no ultrassom com Doppler colorido (USDC no início. Os achados positivos que sugeriram colite foram paredes intestinais espessas e aumento na vascularização, principalmente no cólon descendente e sigmoide. Os resultados da colonoscopia e histopatológicos foram compatíveis com colite alérgica. Após uma mudança na dieta, os 13 neonatos se recuperaram e seus testes de provocação oral foram positivos. CONCLUSÃO: o US com Doppler pode ser muito útil para diagnosticar a colite secundária, como a ALV, e para excluir várias outras doenças abdominais que podem imitar essa doença.

  8. New Approaches For Asteroid Spin State and Shape Modeling From Delay-Doppler Radar Images

    Science.gov (United States)

    Raissi, Chedy; Lamee, Mehdi; Mosiane, Olorato; Vassallo, Corinne; Busch, Michael W.; Greenberg, Adam; Benner, Lance A. M.; Naidu, Shantanu P.; Duong, Nicholas

    2016-10-01

    Delay-Doppler radar imaging is a powerful technique to characterize the trajectories, shapes, and spin states of near-Earth asteroids; and has yielded detailed models of dozens of objects. Reconstructing objects' shapes and spins from delay-Doppler data is a computationally intensive inversion problem. Since the 1990s, delay-Doppler data has been analyzed using the SHAPE software. SHAPE performs sequential single-parameter fitting, and requires considerable computer runtime and human intervention (Hudson 1993, Magri et al. 2007). Recently, multiple-parameter fitting algorithms have been shown to more efficiently invert delay-Doppler datasets (Greenberg & Margot 2015) - decreasing runtime while improving accuracy. However, extensive human oversight of the shape modeling process is still required. We have explored two new techniques to better automate delay-Doppler shape modeling: Bayesian optimization and a machine-learning neural network.One of the most time-intensive steps of the shape modeling process is to perform a grid search to constrain the target's spin state. We have implemented a Bayesian optimization routine that uses SHAPE to autonomously search the space of spin-state parameters. To test the efficacy of this technique, we compared it to results with human-guided SHAPE for asteroids 1992 UY4, 2000 RS11, and 2008 EV5. Bayesian optimization yielded similar spin state constraints within a factor of 3 less computer runtime.The shape modeling process could be further accelerated using a deep neural network to replace iterative fitting. We have implemented a neural network with a variational autoencoder (VAE), using a subset of known asteroid shapes and a large set of synthetic radar images as inputs to train the network. Conditioning the VAE in this manner allows the user to give the network a set of radar images and get a 3D shape model as an output. Additional development will be required to train a network to reliably render shapes from delay-Doppler

  9. Doppler radar physiological sensing

    CERN Document Server

    Lubecke, Victor M; Droitcour, Amy D; Park, Byung-Kwon; Singh, Aditya

    2016-01-01

    Presents a comprehensive description of the theory and practical implementation of Doppler radar-based physiological monitoring. This book includes an overview of current physiological monitoring techniques and explains the fundamental technology used in remote non-contact monitoring methods. Basic radio wave propagation and radar principles are introduced along with the fundamentals of physiological motion and measurement. Specific design and implementation considerations for physiological monitoring radar systems are then discussed in detail. The authors address current research and commercial development of Doppler radar based physiological monitoring for healthcare and other applications.

  10. The phenomenon of Doppler

    International Nuclear Information System (INIS)

    Stoll, I.; Seidlerova, I.; Schwippel, J.; Poss, O.; Solc, M.

    1992-01-01

    The book is devoted to the life and work of Christian Doppler and particularly to his links to Prague and to the Slovak town of Banska Stiavnica. Many historical facts concerning Doppler's activities as well as the history of physics and astronomy are collected. Information is also presented about the Czech Technical University, the Society of Czechoslovak Mathematicians and Physicists, the Czechoslovak Astronomical Society, the Czechoslovak Spectroscopic Society and the Czechoslovak Society for the History of Science and Technology. The publication is amply supplemented with historical pictorial material (M.D.). 92 figs., 82 refs

  11. Doppler ultrasound in obstetrics and gynecology. 2. rev. and enl. ed.

    International Nuclear Information System (INIS)

    Maulik, D.

    2005-01-01

    The second edition of Doppler Ultrasound in Obstetrics and Gynecology has been expanded and comprehensively updated to present the current standards of practice in Doppler ultrasound and the most recent developments in the technology. Doppler Ultrasound in Obstetrics and Gynecology encompasses the full spectrum of clinical applications of Doppler ultrasound for the practicing obstetrician-gynecologist, including the latest advances in 3D and color Doppler and the newest techniques in 4D fetal echocardiography. Written by preeminent experts in the field, the book covers the basic and physical principles of Doppler ultrasound; the use of Doppler for fetal examination, including fetal cerebral circulation; Doppler echocardiography of the fetal heart; and the use of Doppler for postdated pregnancy and in cases of multiple gestation. Chapters on the use of Doppler for gynecologic investigation include ultrasound in ectopic pregnancy, for infertility, for benign disorders and for gynecologic malignancies. (orig.)

  12. Doppler ultrasound in obstetrics and gynecology. 2. rev. and enl. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Maulik, D. [Winthrop Univ. Hospital, Mineola, NY (United States). Dept. of Obstetrics and Gynecology; Zalud, I. (eds.) [Kapiolani Medical Center for Women and Children, Honolulu, HI (United States)

    2005-07-01

    The second edition of Doppler Ultrasound in Obstetrics and Gynecology has been expanded and comprehensively updated to present the current standards of practice in Doppler ultrasound and the most recent developments in the technology. Doppler Ultrasound in Obstetrics and Gynecology encompasses the full spectrum of clinical applications of Doppler ultrasound for the practicing obstetrician-gynecologist, including the latest advances in 3D and color Doppler and the newest techniques in 4D fetal echocardiography. Written by preeminent experts in the field, the book covers the basic and physical principles of Doppler ultrasound; the use of Doppler for fetal examination, including fetal cerebral circulation; Doppler echocardiography of the fetal heart; and the use of Doppler for postdated pregnancy and in cases of multiple gestation. Chapters on the use of Doppler for gynecologic investigation include ultrasound in ectopic pregnancy, for infertility, for benign disorders and for gynecologic malignancies. (orig.)

  13. New Insights from Inside-Out Doppler Tomography

    Directory of Open Access Journals (Sweden)

    E. J. Kotze

    2015-02-01

    Full Text Available We present preliminary results from our investigation into using an “inside-out” velocity space for creating a Doppler tomogram. The aim is to transpose the inverted appearance of the Cartesian velocity space used in normal Doppler tomography. In a comparison between normal and inside-out Doppler tomograms of cataclysmic variables, we show that the inside-out velocity space has the potential to produce new insights into the accretion dynamics in these systems.

  14. Measurement of ventricular function using Doppler ultrasound

    International Nuclear Information System (INIS)

    Teague, S.M.

    1986-01-01

    Doppler has wide application in the evaluation of valvular heart disease. The need to know ventricular function is a much more common reason for an echocardiographic evaluation. Interestingly, Doppler examinations can assess ventricular function from many perspectives. Description of ventricular function entails measurement of the timing, rate and volume of ventricular filling and ejection. Doppler ultrasound examination reveals all of these aspects of ventricular function noninvasively, simply, and without great expense or radiation exposure, as described in this chapter

  15. MP3 compression of Doppler ultrasound signals.

    Science.gov (United States)

    Poepping, Tamie L; Gill, Jeremy; Fenster, Aaron; Holdsworth, David W

    2003-01-01

    The effect of lossy, MP3 compression on spectral parameters derived from Doppler ultrasound (US) signals was investigated. Compression was tested on signals acquired from two sources: 1. phase quadrature and 2. stereo audio directional output. A total of 11, 10-s acquisitions of Doppler US signal were collected from each source at three sites in a flow phantom. Doppler signals were digitized at 44.1 kHz and compressed using four grades of MP3 compression (in kilobits per second, kbps; compression ratios in brackets): 1400 kbps (uncompressed), 128 kbps (11:1), 64 kbps (22:1) and 32 kbps (44:1). Doppler spectra were characterized by peak velocity, mean velocity, spectral width, integrated power and ratio of spectral power between negative and positive velocities. The results suggest that MP3 compression on digital Doppler US signals is feasible at 128 kbps, with a resulting 11:1 compression ratio, without compromising clinically relevant information. Higher compression ratios led to significant differences for both signal sources when compared with the uncompressed signals. Copyright 2003 World Federation for Ultrasound in Medicine & Biology

  16. Analysis of Doppler effect with JAERI-Fast set

    International Nuclear Information System (INIS)

    Takano, Hideki; Matsui, Yasushi.

    1977-07-01

    Temperature dependence of group cross sections in the JAERI-Fast set versions I, IR, II and IIR has been tested from the analysis of Doppler experiments performed with two different methods. One is Doppler reactivity measurement for the whole core of SEFOR assembly, and the other sample Doppler reactivity measurement for natural UO 2 in FCA assemblies V-1, V-2, VI-1 and VI-2, ZPR-6-7, ZPR-3-47, and ZPPR-2 and 3. Doppler effects were calculated with one- and two-dimensional diffusion 1-st order perturbation code DOPP2D. The results calculated with the JAERI-Fast set versions II and IIR are in good agreement with the experimental ones. In these calculation, resonance heterogeneity effect, stainless-stell buffer effect and plate heterogeneity effect are considered, and these effects contribute significantly to Doppler effect. (auth.)

  17. Ecocardiografia por Doppler tecidual no diagnóstico de rejeição após transplante cardíaco Ecocardiografía con Doppler tisular en el diagnóstico de rechazo después de transplante cardíaco Tissue doppler echocardiography in the diagnosis of heart transplantation rejection

    Directory of Open Access Journals (Sweden)

    Marcos Valério Coimbra Resende

    2011-07-01

    Full Text Available FUNDAMENTO: A biópsia endomiocárdica (BEM é o método padrão-ouro para o diagnóstico de rejeição celular (RC após transplante cardíaco (TC. OBJETIVO: Testar a hipótese de que o exame de imagem por Doppler tecidual (IDT pode detectar RC > 3A e agregar informação diagnóstica, comparado ao Doppler convencional. MÉTODOS: Cinquenta e quatro pacientes com TC foram submetidos à BEM e estudo ecocardiográfico através de IDT em até 24 horas. Comparamos os pacientes com TC e RC > 3A com pacientes com TC e RC 3A em 39/129 (30,2% das BEM. O melhor preditor isolado para o diagnóstico de RC foi a a'LAT, com sensibilidade de 76,3%, especificidade de 73,8% (p = 0,001. Na análise multivariada, a a'LAT (p = 0,001, a'SEP (p = 0,002, relação e'/a' LAT (p = 0,006, relação e'Mitral/ e'LAT (p = 0,014, SINF (p = 0,009 foram preditores de RC > 3A. Obtivemos um escore com sensibilidade de 88,2%, acurácia de 79,6%, e valor preditivo negativo de 92,9% para diagnosticar RC > 3A. O Doppler convencional (fluxo mitral e pulmonar venoso não foi relevante para predizer a RC > 3A. CONCLUSÃO: O estudo de IDT agregou informação diagnóstica para predizer RC > 3A quando comparado ao Doppler convencional. O modelo baseado em IDT pode ser tornar um método em potencial para detectar RC > 3A após TC.FUNDAMENTO: La biopsia endomiocárdica (BEM es el método gold standard para el diagnóstico de rechazo celular (RC después de transplante cardíaco (TC. OBJETIVO: Testear la hipótesis de que el examen de imagen con Doppler tisular (IDT puede detectar RC > 3A y agregar información diagnóstica, comparado al Doppler convencional. MÉTODOS: Cincuenta y cuatro pacientes con TC fueron sometidos a BEM y estudio ecocardiográfico a través de IDT en hasta 24 horas. Comparamos los pacientes con TC y RC > 3A con pacientes con TC y RC 3A en 39/129 (30,2% de las BEM. El mejor predictor aislado para el diagnóstico de RC fue la a'LAT, con sensibilidad de 76

  18. Doppler ion program description

    International Nuclear Information System (INIS)

    Henline, P.

    1980-12-01

    The Doppler spectrometer is a conventional Czerny-Turner grating spectrometer with a 1024 channel multiple detector. Light is dispersed across the detector, and its output yields a spectrum covering approximately 200 A. The width of the spectral peak is directly proportional to the temperature of the emitting ions, and determination of the impurity ion temperature allows one to infer the plasma ion temperature. The Doppler ion software system developed at General Atomic uses a TRACOR Northern 1710-31 and an LSI-11/2. The exact configuration of Doublet III is different from TRACOR Northern systems at other facilities

  19. Complex regression Doppler optical coherence tomography

    Science.gov (United States)

    Elahi, Sahar; Gu, Shi; Thrane, Lars; Rollins, Andrew M.; Jenkins, Michael W.

    2018-04-01

    We introduce a new method to measure Doppler shifts more accurately and extend the dynamic range of Doppler optical coherence tomography (OCT). The two-point estimate of the conventional Doppler method is replaced with a regression that is applied to high-density B-scans in polar coordinates. We built a high-speed OCT system using a 1.68-MHz Fourier domain mode locked laser to acquire high-density B-scans (16,000 A-lines) at high enough frame rates (˜100 fps) to accurately capture the dynamics of the beating embryonic heart. Flow phantom experiments confirm that the complex regression lowers the minimum detectable velocity from 12.25 mm / s to 374 μm / s, whereas the maximum velocity of 400 mm / s is measured without phase wrapping. Complex regression Doppler OCT also demonstrates higher accuracy and precision compared with the conventional method, particularly when signal-to-noise ratio is low. The extended dynamic range allows monitoring of blood flow over several stages of development in embryos without adjusting the imaging parameters. In addition, applying complex averaging recovers hidden features in structural images.

  20. Cross-correlation Doppler global velocimetry (CC-DGV)

    Science.gov (United States)

    Cadel, Daniel R.; Lowe, K. Todd

    2015-08-01

    A flow velocimetry method, cross-correlation Doppler global velocimetry (CC-DGV), is presented as a robust, simplified, and high dynamic range implementation of the Doppler global/planar Doppler velocimetry technique. A sweep of several gigahertz of the vapor absorption spectrum is used for each velocity sample, with signals acquired from both Doppler-shifted scattered light within the flow and a non-Doppler shifted reference beam. Cross-correlation of these signals yields the Doppler shift between them, averaged over the duration of the scan. With presently available equipment, velocities from 0 ms-1 to over 3000 ms-1 can notionally be measured simultaneously, making the technique ideal for high speed flows. The processing routine is shown to be robust against large changes in the vapor pressure of the iodine cell, benefiting performance of the system in facilities where ambient conditions cannot be easily regulated. Validation of the system was performed with measurements of a model wind turbine blade boundary layer made in a 1.83 m by 1.83 m subsonic wind tunnel for which laser Doppler velocimetry (LDV) measurements were acquired alongside the CC-DGV results. CC-DGV uncertainties of ±1.30 ms-1, ±0.64 ms-1, and ±1.11 ms-1 were determined for the orthogonal stream-wise, transverse-horizontal, and transverse-vertical velocity components, and root-mean-square deviations of 2.77 ms-1 and 1.34 ms-1 from the LDV validation results were observed for Reynolds numbers of 1.5 million and 2 million, respectively. Volumetric mean velocity measurements are also presented for a supersonic jet, with velocity uncertainties of ±4.48 ms-1, ±16.93 ms-1, and ±0.50 ms-1 for the orthogonal components, and self-validation done by collapsing the data with a physical scaling.

  1. Editorial special issue on "Laser Doppler vibrometry"

    Science.gov (United States)

    Vanlanduit, Steve; Dirckx, Joris

    2017-12-01

    The invention of the laser in 1960 has opened up many opportunities in the field of measurement science and technology. Just a few years after the invention of the laser, a novel fluid flow measurement technique based on the Doppler effect was introduced: at that moment the laser Doppler anemometer or shortly LDA [1] was born. The technique enabled fluid velocity measurement by using the light of a He-Ne beam which was scattered by very small polystyrene spheres entrained in the fluid. Later on, in the late nineteen seventees it was recognized that the detection of the Doppler frequency shift that occurs when light is scattered by a moving surface can also be used to measure the vibration velocity of an object. The instrument to perform these vibration measurements was called the laser Doppler vibrometer or LDV [2]. In the last decades several technological advances were made in the field of laser Doppler vibrometry. The result is that nowadays, velocity measurements of fluids (using LDA) and vibrating objects (using LDV) are performed in many challenging applications in different fields (microelectronics, civil structures, biomedical engineering, material science, etc.).

  2. Glare Spot Phase Doppler Anemometry

    OpenAIRE

    Hespel, Camille; Ren, Kuan Fang; Gréhan, Gérard; Onofri, Fabrice

    2006-01-01

    International audience; The Phase Doppler anemometry has been developed to measure simultaneously the velocity and the size of droplets. The measurement of the refractive index is also necessary since it depends on the temperature and the composition of the particle and its measurement permits both to increase the quality of the diameter measurement and to obtain information on the temperature and/or the composition of the droplets. In this paper, we introduce a Glare Spot Phase Doppler Anemo...

  3. Radar Doppler Processing with Nonuniform Sampling.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-07-01

    Conventional signal processing to estimate radar Doppler frequency often assumes uniform pulse/sample spacing. This is for the convenience of t he processing. More recent performance enhancements in processor capability allow optimally processing nonuniform pulse/sample spacing, thereby overcoming some of the baggage that attends uniform sampling, such as Doppler ambiguity and SNR losses due to sidelobe control measures.

  4. Doppler echocardiography in pediatric cardiology

    International Nuclear Information System (INIS)

    Allen, H.D.; Marx, G.R.

    1986-01-01

    Congenital heart disease encompasses abnormalities in cardiac development which generally have in common either valve stenoses or connections between chambers or great vessels. Usually, abnormalities of intracardiac anatomy, and often, abnormalities of great vessel anatomy, can be unraveled by two-dimensional echocardiography. However, echocardiography offers little information regarding flow characteristics in the various congenital lesions. Addition of the Doppler principle, particularly when combined with the two-dimensional examination, can characterize the source of a flow disturbance, quantify gradients across a site of obstruction, and quantify flow volume across sites where flow is nonturbulent. These features make Doppler echocardiography unique for noninvasive accurate evaluation of children and adults with various forms of congenital heart disease. In this report, the authors discuss some of the present uses of Doppler echocardiography in congenital heart disease. Application of this technique requires greater understanding of certain physics principles than does routine echocardiography

  5. Doppler ultrasound scan during normal gestation: umbilical circulation; Ecografia Doppler en la gestacion normal: circulacion umbilical

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, T.; Sabate, J.; Martinez-Benavides, M. M.; Sanchez-Ramos, J. [Hospital Virgen Macarena. Sevilla (Spain)

    2002-07-01

    To determine normal umbilical circulation patterns by means of Doppler ultrasound scan in a healthy gestating population without risk factors and with normal perinatal results, and to evaluate any occurring modifications relative to gestational age by obtaining records kept during pregnancy. One hundred and sixteen pregnant women carrying a single fetus have been studied. These women had no risk factors, with both clinical and analytical controls, as well as ultrasound scans, all being normal. There were performed a total of 193 Doppler ultrasound scans between weeks 15 and 41 of gestation, with blood-flow analysis in the arteries and vein of the umbilical cord. The obtained information was correlated with parameters that evaluate fetal well-being (fetal monitoring and/or oxytocin test) and perinatal result (delivery type, birth weight, Apgar score). Statistical analysis was performed with the programs SPSS 6.0.1 for Windows and EPIINFO 6.0.4. With pulsed Doppler, the umbilical artery in all cases demonstrated a biphasic morphology with systolic and diastolic components and without retrograde blood flow. As the gestation period increased, there was observed a progressive decrease in resistance along with an increase in blood-flow velocity during the diastolic phase. The Doppler ultrasound scan is a non-invasive method that permits the hemodynamic study of umbilical blood circulation. A knowledge of normal blood-flow signal morphology, as well as of the normal values for Doppler indices in relation to gestational age would permit us to utilize this method in high-risk pregnancies. (Author) 30 refs.

  6. Longitudinal study of aortic isthmus Doppler in appropriately grown and small-for-gestational-age fetuses with normal and abnormal umbilical artery Doppler.

    LENUS (Irish Health Repository)

    Kennelly, M M

    2012-04-01

    To establish reference ranges using longitudinal data for aortic isthmus (AoI) Doppler indices in appropriate-for-gestational-age (AGA) fetuses and to document the longitudinal trends in a cohort of small-for-gestational-age (SGA) fetuses with normal umbilical artery Doppler and in fetuses with intrauterine growth restriction (IUGR) and abnormal umbilical artery Doppler.

  7. Musculoskeletal colour/power Doppler in sports medicine

    DEFF Research Database (Denmark)

    Boesen, M I; Boesen, M; Langberg, Henning

    2010-01-01

    This review article discusses the aspects of sports medicine where musculoskeletal Doppler ultrasound has valuable contribution in diagnosis and/or treatment of some of the typical musculoskeletal sports injuries. Also, conditions where the Doppler ultrasound has no value are discussed. Some...

  8. Chemical quenching of positronium in Fe2O3/Al2O3 catalysts

    International Nuclear Information System (INIS)

    Li, C.; Zhang, H.J.; Chen, Z.Q.

    2010-01-01

    Fe 2 O 3 /Al 2 O 3 catalysts were prepared by solid state reaction method using α-Fe 2 O 3 and γ-Al 2 O 3 nano powders. The microstructure and surface properties of the catalyst were studied using positron lifetime and coincidence Doppler broadening annihilation radiation measurements. The positron lifetime spectrum shows four components. The two long lifetimes τ 3 and τ 4 are attributed to positronium annihilation in two types of pores distributed inside Al 2 O 3 grain and between the grains, respectively. With increasing Fe 2 O 3 content from 3 wt% to 40 wt%, the lifetime τ 3 keeps nearly unchanged, while the longest lifetime τ 4 shows decrease from 96 ns to 64 ns. Its intensity decreases drastically from 24% to less than 8%. The Doppler broadening S parameter shows also a continuous decrease. Further analysis of the Doppler broadening spectra reveals a decrease in the p-Ps intensity with increasing Fe 2 O 3 content, which rules out the possibility of spin-conversion of positronium. Therefore the decrease of τ 4 is most probably due to the chemical quenching reaction of positronium with Fe ions on the surface of the large pores.

  9. Chemical quenching of positronium in Fe 2O 3/Al 2O 3 catalysts

    Science.gov (United States)

    Li, C.; Zhang, H. J.; Chen, Z. Q.

    2010-09-01

    Fe 2O 3/Al 2O 3 catalysts were prepared by solid state reaction method using α-Fe 2O 3 and γ-Al 2O 3 nano powders. The microstructure and surface properties of the catalyst were studied using positron lifetime and coincidence Doppler broadening annihilation radiation measurements. The positron lifetime spectrum shows four components. The two long lifetimes τ3 and τ4 are attributed to positronium annihilation in two types of pores distributed inside Al 2O 3 grain and between the grains, respectively. With increasing Fe 2O 3 content from 3 wt% to 40 wt%, the lifetime τ3 keeps nearly unchanged, while the longest lifetime τ4 shows decrease from 96 ns to 64 ns. Its intensity decreases drastically from 24% to less than 8%. The Doppler broadening S parameter shows also a continuous decrease. Further analysis of the Doppler broadening spectra reveals a decrease in the p-Ps intensity with increasing Fe 2O 3 content, which rules out the possibility of spin-conversion of positronium. Therefore the decrease of τ4 is most probably due to the chemical quenching reaction of positronium with Fe ions on the surface of the large pores.

  10. Temporal enhancement of two-dimensional color doppler echocardiography

    Science.gov (United States)

    Terentjev, Alexey B.; Settlemier, Scott H.; Perrin, Douglas P.; del Nido, Pedro J.; Shturts, Igor V.; Vasilyev, Nikolay V.

    2016-03-01

    Two-dimensional color Doppler echocardiography is widely used for assessing blood flow inside the heart and blood vessels. Currently, frame acquisition time for this method varies from tens to hundreds of milliseconds, depending on Doppler sector parameters. This leads to low frame rates of resulting video sequences equal to tens of Hz, which is insufficient for some diagnostic purposes, especially in pediatrics. In this paper, we present a new approach for reconstruction of 2D color Doppler cardiac images, which results in the frame rate being increased to hundreds of Hz. This approach relies on a modified method of frame reordering originally applied to real-time 3D echocardiography. There are no previous publications describing application of this method to 2D Color Doppler data. The approach has been tested on several in-vivo cardiac 2D color Doppler datasets with approximate duration of 30 sec and native frame rate of 15 Hz. The resulting image sequences had equivalent frame rates to 500Hz.

  11. Um Novo Indice de Doppler Tecidual para Prever Morte Cardiaca em Pacientes com Insuficiencia Cardiaca

    Directory of Open Access Journals (Sweden)

    Cristian Mornos

    2014-01-01

    Full Text Available Fundamento: Foi demonstrado que um novo índice de Doppler Tecidual, E/(E'×S', incluindo a proporção entre a velocidade diastólica precoce transmitral e a do anel mitral (E/E', e a velocidade sistólica do anel mitral (S', tem uma boa precisão como preditor da pressão de enchimento do ventrículo esquerdo. Objetivo: Investigar o valor de E/(E'×S' para prever a morte cardíaca em pacientes com insuficiência cardíaca. Métodos: Foi realizado sucessivamente o ecocardiograma em 339 pacientes hospitalizados com insuficiência cardíaca, em ritmo sinusal, após tratamento médico adequado, no momento e um mês depois da alta. O agravamento de E/(E'×S' foi definido como um aumento do valor padrão. O ponto final foi a morte cardíaca. Resultados: Durante o período de acompanhamento (35,2 ± 8,8 meses, ocorreu a morte cardíaca em 51 pacientes (15%. O melhor valor mínimo para E/(E'× S' inicial na previsão da morte cardíaca foi de 2,83 (76% de sensibilidade, 85% de especificidade. No momento da alta, 252 pacientes (74,3% apresentaram E/(E'×S' ≤ 2,83 (grupo I, e 87 (25,7% apresentaram E/(E'×S' > 2,83 (grupo II, respectivamente. A morte cardíaca foi significativamente maior no grupo II em relação ao grupo I (38 mortes, 43,7% contra 13 mortes, 5,15%, p 2,83 no momento da alta e com um agravamento após um mês apresentaram o pior prognóstico (todos p < 0,05. Conclusão: Em pacientes com insuficiência cardíaca a relação E/(E'×S' é um poderoso preditor da morte cardíaca, especialmente quando esta estiver associada com o seu agravamento.

  12. Doppler US evaluation of the hypertensive portal system

    International Nuclear Information System (INIS)

    Needleman, L.; Kurtz, A.B.; Bezzi, M.; Rifkin, M.D.; Pasto, M.E.; Pennell, R.G.; Baltarowich, O.H.; Goldberg, B.B.

    1986-01-01

    In patients with known portal hypertension, pulsed Doppler US was used for qualitative and directional evaluation of flow in the portal venous system and collateral vessels. Most patients had normal hepatopetal flow. Doppler US revealed the following abnormal blood flow patterns: hepatofugal portal flow, bidirectional portal flow, intrahepatic portal shunting, flow in portasystemic collaterals, and hepatic vein obstruction. Doppler US can provide important clinical information in the evaluation of portal hypertension

  13. The image of urachus adenocarcinoma on Doppler ultrasonography

    Energy Technology Data Exchange (ETDEWEB)

    Oyar, Orhan E-mail: o_oyar@hotmail.com; Yesildag, Ahmet; Gulsoy, Ufuk Kemal; Perk, Hakki

    2002-10-01

    Malignant urachal lesions are exceedingly rare and occur predominantly in adult life. In this case report, an adult patient with urachal carcinoma is presented with abdominal plain film, intravenous urography, gray-scale ultrasonography (US), Doppler US, and computed tomography (CT). Doppler US successfully showed the neovascularity with low resistive index value in the urachus tumor. We believe that Doppler US examination is helpful in the differential diagnosis of urachal carcinoma.

  14. Positron annihilation study of vacancy-type defects in fast-neutron-irradiated MgO·nAl2O3

    International Nuclear Information System (INIS)

    Rahman, Abu Zayed Mohammad Saliqur; Li, Zhuoxin; Cao, Xingzhong; Wang, Baoyi; Wei, Long; Xu, Qiu; Atobe, Kozo

    2014-01-01

    Highlights: •Detection of Al monovacancy by positron lifetime spectroscopy in fast neutron-irradiated MgO·nAl 2 O 3 (n=2). •Concentration of defects is also estimated for Al monovacancy. •O atom peak was observed by using coincidence Doppler broadening spectroscopy. -- Abstract: The positron lifetimes of fast-neutron-irradiated MgO·nAl 2 O 3 single crystals were measured to investigate the formation of cation vacancies. Al monovacancy was possibly observed in samples irradiated by fast neutrons at ultra-low temperatures. Additionally, vacancy-oxygen complex centers were possibly observed in samples irradiated at higher temperatures and fast neutron fluences. Coincidence Doppler broadening (CDB) spectra were measured to obtain information regarding the vicinity of vacancy-type defects. A peak at approximately 11 × 10 −3 m 0 c was observed, which may be due to the presence of oxygen atoms in the neighborhood of the vacancies

  15. Doppler coefficient measurements in Zebra Core 5

    International Nuclear Information System (INIS)

    Baker, A.R.; Wheeler, R.C.

    1965-11-01

    Measurements using a central hot loop in Zebra Core 5 are described. Results are given for the Doppler coefficients found in a number of assemblies with PuO 2 and 16% PuO 2 /84% depleted UO 2 pins, loaded with different combinations of steel, sodium or void pins. The mixed oxide results are in general about 20% more negative than was calculated using the FD2 data set, but agreement is good if the plutonium contributions in the calculations are omitted. The small positive Doppler coefficient calculated for Pu239 was not observed, and two measurements indicated instead a small negative effect. The Doppler effect in the mixed oxide systems was found to vary approximately as 1/T. The results from the empty loop and non-fissile assemblies indicate either a small negative Doppler effect in steel or alternatively the presence of an unexplained expansion effect. (author)

  16. Analysis of Radar Doppler Signature from Human Data

    Directory of Open Access Journals (Sweden)

    M. ANDRIĆ

    2014-04-01

    Full Text Available This paper presents the results of time (autocorrelation and time-frequency (spectrogram analyses of radar signals returned from the moving human targets. When a radar signal falls on the human target which is moving toward or away from the radar, the signals reflected from different parts of his body produce a Doppler shift that is proportional to the velocity of those parts. Moving parts of the body causes the characteristic Doppler signature. The main contribution comes from the torso which causes the central Doppler frequency of target. The motion of arms and legs induces modulation on the returned radar signal and generates sidebands around the central Doppler frequency, referred to as micro-Doppler signatures. Through analyses on experimental data it was demonstrated that the human motion signature extraction is better using spectrogram. While the central Doppler frequency can be determined using the autocorrelation and the spectrogram, the extraction of the fundamental cadence frequency using the autocorrelation is unreliable when the target is in the clutter presence. It was shown that the fundamental cadence frequency increases with increasing dynamic movement of people and simultaneously the possibility of its extraction is proportional to the degree of synchronization movements of persons in the group.

  17. Evaluating Peripheral Vascular Injuries: Is Color Doppler Enough for Diagnosis?

    Directory of Open Access Journals (Sweden)

    Mohd Lateef Wani

    2014-03-01

    Full Text Available Background:: Vascular injury poses a serious threat to limb and life. Thus, diagnosis should be made immediately with minimally invasive methods. Doppler is a good aid in diagnosis of vascular injury. Methods:: The present prospective study was conducted on 150 patients who presented with soft signs (the signs which are suggestive but not confirmatory of vascular injury. They were subjected to color Doppler examination before exploration. The patients with the features of vascular injury on color Doppler were subjected to exploration. On the other hand, those who had normal Doppler were subjected to CT- angiography. Then, the findings of the exploration were matched with those of color Doppler. The data were analyzed using the SPSS statistical software. Results:: Out of the 150 Doppler examinations, 110 (73.33% were reported as positive, while 40 were reported as negative for vascular injury. These were subjected to CT-angiography and seven of them had the features of vascular injury on CT-angiography. All the patients with positive Doppler or CT angiography findings were subjected to exploration. Doppler had a sensitivity of 94% and specificity of 82.5% in diagnosis of vascular injury using Binary classification test. Conclusions:: Color Doppler is an easily available, reliable, and handy method of diagnosing a vascular injury. It has a very high sensitivity and specificity in diagnosis of vascular injuries.

  18. Digital spectrometer for coincidence measurement of Doppler broadening of positron annihilation radiation

    International Nuclear Information System (INIS)

    Cizek, J.; Vlcek, M.; Prochazka, I.

    2010-01-01

    High-resolution digital coincidence Doppler broadening spectrometer equipped with two high-purity Ge detectors and two-channel 12-bit fast digitizer was developed and tested in this work. Two configurations were compared: (i) semi-digital setup which uses active analogue shaping of detector pulses prior to digitization to improve signal-to-noise ratio, and (ii) pure-digital setup which samples detector pulses directly. Software procedure developed for analysis of sampled waveforms, i.e. precise determination of energy of detected photon and rejection of distorted pulses, is described. Performance of digital coincidence spectrometer was compared with traditional analogue setup connected to the same detectors. It was found that digital spectrometer enables to achieve better energy resolution than in traditional analogue setup. Moreover, in digital configuration one has better control over shape of the signal. This allows efficient elimination of undesired distorted or damaged waveforms and to obtain spectrum of better clarity. The superior parameters of new digital coincidence Doppler broadening spectrometer are demonstrated by benchmark measurements of well defined Fe and Al specimens and also by the detection of rare annihilation in flight events.

  19. Avaliação ecocardiográfica em obesos graves assintomáticos

    OpenAIRE

    Rocha,Isaura Elaine Gonçalves Moreira; Victor,Edgar Guimarães; Braga,Maria Cynthia; Silva,Odwaldo Barbosa e; Becker,Mônica de Moraes Chaves

    2007-01-01

    OBJETIVO: Estudar a função sistólica e diastólica por meio da ecocardiografia Doppler em pacientes assintomáticos com obesidade grave. MÉTODOS: Foram avaliados, por meio de ecocardiograma transtorácico, 30 pacientes candidatos a cirurgia bariátrica, com IMC médio de 49,2±8,8 kg/m², sem história de cardiopatia prévia. RESULTADOS: Observou-se aumento de câmaras esquerdas em 42,9% da amostra, disfunção diastólica em 54,6%, hipertrofia ventricular esquerda em 82,1%, com padrão geométrico do tipo ...

  20. Sub-Doppler laser cooling of potassium atoms

    Energy Technology Data Exchange (ETDEWEB)

    Landini, M. [LENS and Dipartimento di Fisica e Astronomia, Universita di Firenze, I-50019 Sesto Fiorentino (Italy); INFN, Sezione di Firenze, I-50019 Sesto Fiorentino (Italy); Dipartimento di fisica, Universita di Trento, I-38123 Povo (Trento) (Italy); Roy, S.; Carcagni, L.; Trypogeorgos, D. [LENS and Dipartimento di Fisica e Astronomia, Universita di Firenze, I-50019 Sesto Fiorentino (Italy); Fattori, M.; Inguscio, M.; Modugno, G. [LENS and Dipartimento di Fisica e Astronomia, Universita di Firenze, I-50019 Sesto Fiorentino (Italy); INFN, Sezione di Firenze, I-50019 Sesto Fiorentino (Italy)

    2011-10-15

    We investigate the sub-Doppler laser cooling of bosonic potassium isotopes, whose small hyperfine splitting has so far prevented cooling below the Doppler temperature. We find instead that the combination of a dark optical molasses scheme that naturally arises in this kind of system and an adiabatic ramping of the laser parameters allows us to reach sub-Doppler temperatures for small laser detunings. We demonstrate temperatures as low as 25{+-}3 {mu}K and 47{+-}5 {mu}K in high-density samples of the two isotopes {sup 39}K and {sup 41}K, respectively. Our findings should find application to other atomic systems.

  1. Sub-Doppler laser cooling of potassium atoms

    International Nuclear Information System (INIS)

    Landini, M.; Roy, S.; Carcagni, L.; Trypogeorgos, D.; Fattori, M.; Inguscio, M.; Modugno, G.

    2011-01-01

    We investigate the sub-Doppler laser cooling of bosonic potassium isotopes, whose small hyperfine splitting has so far prevented cooling below the Doppler temperature. We find instead that the combination of a dark optical molasses scheme that naturally arises in this kind of system and an adiabatic ramping of the laser parameters allows us to reach sub-Doppler temperatures for small laser detunings. We demonstrate temperatures as low as 25±3 μK and 47±5 μK in high-density samples of the two isotopes 39 K and 41 K, respectively. Our findings should find application to other atomic systems.

  2. Methodology for obtaining wind gusts using Doppler lidar

    DEFF Research Database (Denmark)

    Suomi, Irene; Gryning, Sven-Erik; O'Connor, Ewan J.

    2017-01-01

    reduced the bias in the Doppler lidar gust factors from 0.07 to 0.03 and can be improved further to reduce the bias by using a realistic estimate of turbulence. Wind gust measurements are often prone to outliers in the time series, because they represent the maximum of a (moving-averaged) horizontal wind...... detection also outperformed the traditional Doppler lidar quality assurance method based on carrier-to-noise ratio, by removing additional unrealistic outliers present in the time series.......A new methodology is proposed for scaling Doppler lidar observations of wind gusts to make them comparable with those observed at a meteorological mast. Doppler lidars can then be used to measure wind gusts in regions and heights where traditional meteorological mast measurements are not available...

  3. Corruption of radio metric Doppler due to solar plasma dynamics: S/X dual-frequency Doppler calibration for these effects

    Science.gov (United States)

    Winn, F. B.; Reinbold, S. R.; Yip, K. W.; Koch, R. E.; Lubeley, A.

    1975-01-01

    Doppler data from Mariner 6, 7, 9, and 10 and Pioneer 10 and 11 were discussed and the rms noise level for various sun-earth-probe angles were shown. The noise levels of both S- and X-band Doppler data for sun-earth-probe angles smaller than 20 deg were observed to be orders of magnitude greater than nominal. Such solar plasma-related Doppler degradation reduced the Mariner 10-Mercury 11 encounter navigation accuracy by nearly a factor of 10. Furthermore, this degradation was shown to be indirectly related to plasma dynamics and not a direct measure of the dynamics.

  4. Doppler Velocity Signatures of Idealized Elliptical Vortices

    Directory of Open Access Journals (Sweden)

    Wen-Chau Lee

    2006-01-01

    Full Text Available Doppler radar observations have revealed a class of atmospheric vortices (tropical cyclones, tornadoes, dust devils that possess elliptical radar reflectivity signatures. One famous example is Typhoon Herb (1996 that maintained its elliptical reflectivity structure over a 40-hour period. Theoretical work and dual-Doppler analyses of observed tropical cyclones have suggested two physical mechanisms that can explain the formation of two types of elliptical vortices observed in nature, namely, the combination of a circular vortex with either a wavenumber two vortex Rossby wave or a deformation field. The characteristics of these two types of elliptical vortices and their corresponding Doppler velocity signatures have not been previously examined.

  5. TCSP ER-2 DOPPLER RADAR (EDOP) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The EDOP provides vertically profiled reflectivity and Doppler velocity at aircraft nadir along the flight track. The ER-2 Doppler radar (EDOP) is an X-band (9.6...

  6. Gold nanorods as a contrast agent for Doppler optical coherence tomography.

    Directory of Open Access Journals (Sweden)

    Bo Wang

    Full Text Available To investigate gold nanorods (GNRs as a contrast agent to enhance Doppler optical coherence tomography (OCT imaging of the intrascleral aqueous humor outflow.A serial dilution of GNRs was scanned with a spectral-domain OCT device (Bioptigen, Durham, NC to visualize Doppler signal. Doppler measurements using GNRs were validated using a controlled flow system. To demonstrate an application of GNR enhanced Doppler, porcine eyes were perfused at constant pressure with mock aqueous alone or 1.0×10(12 GNR/mL mixed with mock aqueous. Twelve Doppler and volumetric SD-OCT scans were obtained from the limbus in a radial fashion incremented by 30°, forming a circular scan pattern. Volumetric flow was computed by integrating flow inside non-connected vessels throughout all 12 scans around the limbus.At the GNR concentration of 0.7×10(12 GNRs/mL, Doppler signal was present through the entire depth of the testing tube without substantial attenuation. A well-defined laminar flow profile was observed for Doppler images of GNRs flowing through the glass capillary tube. The Doppler OCT measured flow profile was not statistically different from the expected flow profile based upon an autoregressive moving average model, with an error of -0.025 to 0.037 mm/s (p = 0.6435. Cross-sectional slices demonstrated the ability to view anterior chamber outflow ex-vivo using GNR-enhanced Doppler OCT. Doppler volumetric flow measurements were comparable to flow recorded by the perfusion system.GNRs created a measureable Doppler signal within otherwise silent flow fields in OCT Doppler scans. Practical application of this technique was confirmed in a constant pressure ex-vivo aqueous humor outflow model in porcine eyes.

  7. GRIP DOPPLER AEROSOL WIND LIDAR (DAWN) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GRIP Doppler Aerosol WiNd Lidar (DAWN) Dataset was collected by the Doppler Aerosol WiNd (DAWN), a pulsed lidar, which operated aboard a NASA DC-8 aircraft...

  8. Diabetic Nephropathy : Evaluation with Doppler Ultrasonography

    International Nuclear Information System (INIS)

    Sim, Jung Suk; Kim, Seung Hyup; Kang, Heung Sik; Park, Jae Hyung; Han, Man Chung

    1996-01-01

    To compare Doppler ultrasonography with laboratory tests in evaluation of diabetic nephropathy. Fifty-five patients (mean age = 60, M : F = 26 : 29) with diabetes mellitus underwent renal Doppler ultrasonography. Resistive indices were compared with degree of proteinuria, serum creatinine level, and creatinine clearance rate. Eighteen patients who showed no proteinuria or microscopic proteinuria had a mean resistive index (RI) of 0.72 (SD, 0.05), 16 patients with macroscopic proteinuria without nephrotic syndrome had a mean RI of 0.82 (SD, 0.13), and 21 patients with nephrotic syndrome had a mean RI of 0.90 (SD, 0.12). Renal RI correlated highly with serum creatinine level (r = 0.62) and creatinine clearance rate (r = -0.43). Renal Doppler ultrasonography provides a useful indication of renal function in diabetic nephropathy but cannot offer an advantage over conventional laboratory test

  9. Use of Doppler ultrasound for non-invasive urodynamic diagnosis

    Directory of Open Access Journals (Sweden)

    Hideo Ozawa

    2009-01-01

    Full Text Available Objectives: A totally non-invasive transperineal urodynamic technique using Doppler ultrasonography has been developed. Methods: Since normal urine does not have blood cells, urine was thought not to produce the Doppler effects. However, basic studies confirmed that the decrease of pressure at high velocity (Bernouilli effect caused dissolved gas to form microbubbles, which are detected by Doppler ultrasonography. Subjects sat and the probe was advanced via remote control to achieve gentle contact with the perineal skin. The digital uroflow data signals and the color Doppler ultrasound video images were processed on a personal computer. The flow-velocity curves from two sites; the distal prostatic urethra just above the external sphincter (V1 and the sphincteric urethra (V2 were plotted against time. The parameters of both the pressure-flow studies and the Doppler ultrasound urodynamic studies were compared in men who had various degrees of obstruction. Results: Functional cross-sectional area at prostatic urethra (A1, calculated by Q max /V1, was lower in the group of bladder outlet obstruction (BOO vs. control group. Velocity ratio (VR, which was calculated by V1/V2, was the parameter having the best correlation with BOO index, though A1 had a similar correlation. This method is viable to diagnose the degree of BOO. Conclusions: The development of non-invasive Doppler ultrasound videourodynamics (Doppler UDS will dramatically expand the information on voiding function.

  10. Wide Angle Michelson Doppler Imaging Interferometer (WAMDII)

    Science.gov (United States)

    Roberts, B.

    1986-01-01

    The wide angle Michelson Doppler imaging interferometer (WAMDII) is a specialized type of optical Michelson interferometer working at sufficiently long path difference to measure Doppler shifts and to infer Doppler line widths of naturally occurring upper atmospheric Gaussian line emissions. The instrument is intended to measure vertical profiles of atmospheric winds and temperatures within the altitude range of 85 km to 300 km. The WAMDII consists of a Michelson interferometer followed by a camera lens and an 85 x 106 charge coupled device photodiode array. Narrow band filters in a filter wheel are used to isolate individual line emissions and the lens forms an image of the emitting region on the charge coupled device array.

  11. Temporal Doppler Effect and Future Orientation: Adaptive Function and Moderating Conditions.

    Science.gov (United States)

    Gan, Yiqun; Miao, Miao; Zheng, Lei; Liu, Haihua

    2017-06-01

    The objectives of this study were to examine whether the temporal Doppler effect exists in different time intervals and whether certain individual and environmental factors act as moderators of the effect. Using hierarchical linear modeling, we examined the existence of the temporal Doppler effect and the moderating effect of future orientation among 139 university students (Study 1), and then the moderating conditions of the temporal Doppler effect using two independent samples of 143 and 147 university students (Studies 2 and 3). Results indicated that the temporal Doppler effect existed in all of our studies, and that future orientation moderated the temporal Doppler effect. Further, time interval perception mediated the relationship between future orientation and the motivation to cope at long time intervals. Finally, positive affect was found to enhance the temporal Doppler effect, whereas control deprivation did not influence the effect. The temporal Doppler effect is moderated by the personality trait of future orientation and by the situational variable of experimentally manipulated positive affect. We have identified personality and environmental processes that could enhance the temporal Doppler effect, which could be valuable in cases where attention to a future task is necessary. © 2016 Wiley Periodicals, Inc.

  12. Evaluation of Pulsed Doppler-Versus Tissue Doppler-Derived Tei Index of Right and Left Ventricle in Fetuses

    Directory of Open Access Journals (Sweden)

    Hamid Amoozgar

    2011-12-01

    Full Text Available Background: The myocardial performance index (MPI, also known as the Tei index, was introduced by Tei et al. to evaluate cardiac function in adults with dilated cardiomyopathy. This index is defined as the sum of isovolumic contraction time (ICT and isovolumic relaxation time (IRT, divided by ejection time (ET. Objectives: To determine the correlation between pulsed Doppler (PD- and tissue Doppler imaging (TDI-derived Tei indices in fetuses. Patients and Methods: Right and left ventricle PD and TDI echocardiographic data were obtained from 59 fetuses (11 pregnant women who were positive for anti-SSA-Ro or anti-SSB-La antibodies, 18 women who were referred due to dysrhythmia, and 30 women who had normal clinical findings. Results: Mean fetal gestational age was 27 ± 6.4 weeks. Mean PD Tei index of the mitral and tricuspid valve was 0.58 ± 0.05 and 0.53 ± 0.08, respectively. Mean TDI indices for the mitral and tricuspid valve were 0.56 ± 0.09 and 0.55 ± 0.08, respectively. There were no significant differences between mitral and tricuspid PD- and TDI-derived Tei indices (P = 0.87, P= 0.21, but the Bland-Altman diagrams showed no fine agreement between the indices (the mean difference ± 1 standard deviation of the right ventricular PD- and TDI-derived Tei indices was 0.24 ± 0.02 and 0.29 ± 0.04 for the left ventricle. There were no significant differences in PD- and TDI-derived Tei indexes between groups of evaluated fetuses (Mitral valve: PD-Tei P=0.69, TDI-Tei P=0.49; Tricuspid valve: PD-Tei P=0.41, TDI-Tei P=0.36. Conclusions: Although the mean values of the two indices did not differ significantly, the TDI-derived and PD-derived Tei indices did not have fine agreement.

  13. Calculation of the Doppler broadening function using Fourier analysis

    International Nuclear Information System (INIS)

    Goncalves, Alessandro da Cruz

    2010-01-01

    An efficient and precise method for calculation of Doppler broadening function is very important to obtain average group microscopic cross sections, self shielding factors, resonance integrals and others reactor physics parameter. In this thesis two different methods for calculation of Doppler broadening function and interference term will be presented. The main method is based on a new integral form for Doppler broadening function ψ(x,ζ) which gives a mathematical interpretation of the approximation proposed by Bethe and Placzek, as the convolution of the Lorentzian function with a Gaussian function. This interpretation besides leading to a new integral form for ψ(x,ζ), enables to obtain a simple analytic solution for the Doppler broadening function. (author)

  14. New clutter-rejection algorithm for Doppler ultrasound

    Science.gov (United States)

    Cloutier, Guy; Chen, Danmin; Durand, Louis-Gilles

    2002-04-01

    Several strategies, known as clutter or wall Doppler filtering, were proposed to remove the strong echoes produced by stationary or slow moving tissue structures from the Doppler blood flow signal. In this study, the matching pursuit (MP) method is proposed to remove clutter components. The MP method decomposes the Doppler signal into wavelet atoms that are selected in a decreasing energy order. Thus, the high-energy clutter components are extracted first. In the present study, the pulsatile Doppler signal s(n) was simulated by a sum of random-phase sinusoids. Two types of high-amplitude clutter signals were then superimposed on s(n): a time-varying low frequency component (type 1), covering systole and early diastole, and short transient clutter signals (type 2), distributed within the whole cardiac cycle. The Doppler signals were modeled with the MP method and the most dominant atoms were subtracted until the signal-to-clutter (S/C) ratio reached a maximum. For the type 1 clutter signal, the improvement in the S/C ratio was 19.0 +/- 0.6 dB, and 72.0 +/- 4.5 atoms were required to reach this performance. For the transient type 2 clutter signal, exactly 10 atoms were required and the maximum improvement in S/C ratio was 5.5 +/- 0.5 dB. These results suggest the possibility of using this signal processing approach to implement clutter rejection filters on ultrasound commercial instruments.

  15. Inline Ultrasonic Rheometry by Pulsed Doppler

    Energy Technology Data Exchange (ETDEWEB)

    Pfund, David M.; Greenwood, Margaret S.; Bamberger, Judith A.; Pappas, Richard A.

    2006-12-22

    This will be a discussion of the non-invasive determination of the viscosity of a non-Newtonian fluid in laminar pipe flow over the range of shear rates present in the pipe. The procedure used requires knowledge of the flow profile in and the pressure drop along a long straight run of pipe. The profile is determined by using a pulsed ultrasonic Doppler velocimeter. This approach is ideal for making non-invasive, real-time measurements for monitoring and control. Rheograms of a shear thinning, thixotropic gel will be presented. The operating parameters and limitations of the Doppler-based instrument will be discussed. The most significant limitation is velocity gradient broadening of the Doppler spectra near the walls of the pipe. This limitation can be significant for strongly shear thinning fluids (depending also on the ratio of beam to pipe diameter and the transducer's insertion angle).

  16. Molecules cooled below the Doppler limit

    Science.gov (United States)

    Truppe, S.; Williams, H. J.; Hambach, M.; Caldwell, L.; Fitch, N. J.; Hinds, E. A.; Sauer, B. E.; Tarbutt, M. R.

    2017-12-01

    Magneto-optical trapping and sub-Doppler cooling have been essential to most experiments with quantum degenerate gases, optical lattices, atomic fountains and many other applications. A broad set of new applications await ultracold molecules, and the extension of laser cooling to molecules has begun. A magneto-optical trap (MOT) has been demonstrated for a single molecular species, SrF, but the sub-Doppler temperatures required for many applications have not yet been reached. Here we demonstrate a MOT of a second species, CaF, and we show how to cool these molecules to 50 μK, well below the Doppler limit, using a three-dimensional optical molasses. These ultracold molecules could be loaded into optical tweezers to trap arbitrary arrays for quantum simulation, launched into a molecular fountain for testing fundamental physics, and used to study collisions and chemistry between atoms and molecules at ultracold temperatures.

  17. Doppler ultrasound imaging techniques for assessment of synovial inflammation

    Directory of Open Access Journals (Sweden)

    Filippucci E

    2013-09-01

    Full Text Available Emilio Filippucci,1 Fausto Salaffi,1 Marina Carotti,2 Walter Grassi1 1Rheumatology Department, Polytechnic University of the Marche, Ancona, Italy; 2Department of Radiology, Polytechnic University of the Marche, Ancona, Italy Abstract: Ultrasound is an evolving technique, and the rapid progress made in ultrasound technology over the past ten years has dramatically increased its range of applications in rheumatology. One of the most exciting advances is the use of Doppler ultrasound imaging in the assessment of blood flow abnormalities at the synovial tissue level in patients with chronic inflammatory arthritis. This review describes the Doppler techniques available and their main applications in patients with inflammatory arthritis, discusses the evidence supporting their use, and outlines the latest advances in hardware and software. Spectral, color, and power Doppler allow sensitive assessment of vascular abnormalities at the synovial tissue level. Use of contrast agents enhances visualization of the small synovial vessels using color or power Doppler ultrasound and allows for accurate characterization of the rheumatoid pannus. Doppler techniques represent a unique method for assessment of synovial inflammation, showing blood flow characteristics in real time. They are safe, noninvasive, cost-effective, and have high sensitivity in revealing and monitoring synovitis. However, several questions still need to be answered. In the near future, the Doppler techniques described here, together with upcoming hardware and software facilities, will be investigated further and a consensus will be reached on their feasibility and appropriate use in daily rheumatologic practice. Keywords: power and color Doppler techniques, ultrasound, contrast media, synovitis, rheumatoid arthritis

  18. Doppler Shift Compensation Schemes in VANETs

    Directory of Open Access Journals (Sweden)

    F. Nyongesa

    2015-01-01

    Full Text Available Over the last decade vehicle-to-vehicle (V2V communication has received a lot of attention as it is a crucial issue in intravehicle communication as well as in Intelligent Transportation System (ITS. In ITS the focus is placed on integration of communication between mobile and fixed infrastructure to execute road safety as well as nonsafety information dissemination. The safety application such as emergence alerts lays emphasis on low-latency packet delivery rate (PDR, whereas multimedia and infotainment call for high data rates at low bit error rate (BER. The nonsafety information includes multimedia streaming for traffic information and infotainment applications such as playing audio content, utilizing navigation for driving, and accessing Internet. A lot of vehicular ad hoc network (VANET research has focused on specific areas including channel multiplexing, antenna diversity, and Doppler shift compensation schemes in an attempt to optimize BER performance. Despite this effort few surveys have been conducted to highlight the state-of-the-art collection on Doppler shift compensation schemes. Driven by this cause we survey some of the recent research activities in Doppler shift compensation schemes and highlight challenges and solutions as a stock-taking exercise. Moreover, we present open issues to be further investigated in order to address the challenges of Doppler shift in VANETs.

  19. Comparison between Doppler Ultrasound and Biopsy Findings in ...

    African Journals Online (AJOL)

    Methods: We retrospectively studied a random sample of 188 kidney transplanted patients who had Doppler-ultrasound examination followed within two weeks by transplant biopsy. We evaluated the specificity and sensitivity of Doppler ultrasound in diagnosing rejection at different RI thresholds, using the reported biopsy ...

  20. Acute intrascrotal pathology in childhood: color Doppler study

    International Nuclear Information System (INIS)

    Cinta Sanguesa, C.; Muro, D.; Cortina, H.; Moreno, A.

    1997-01-01

    To asses the utility of color Doppler ultrasound in the study of acute intrascrotal pathology in childhood. Seventy-five boys with evidence of an acute intrascrotal abnormality were studied by means of color Doppler ultrasound. A 7.5 MHz linear transducer was used. The most common findings was inflammatory disease (60%) which was indicated by the presence of hyperemia in color Doppler. Of the nine boys with testicular torsion (12%) two presented extravaginal torsion, with a complete absence of intratesticular vascularization. Intravaginal torsion was observed in seven patients, six of whom presented reduced vascularization in the abnormal testicle with respect to the healthy testicle. There was one false negative in which testicular vascularization was normal but 360 degree centigree torsion was found at surgery. In addition, there were seven cases of hydatid torsion (9.33%), four of idiopathic scrotal swelling (5.3%). two cases of intermittent torsion (2.6%) and one case of Shcolein-Henoch purpura (1.3%). The ultrasound findings were completely nornal in seven boys. Color Doppler is a rapid, noninvasive method for assessing testicular blood flow. The elevated sensitivity and specificity (85.7 and 100%, respectively, in our series) for testicular torsion make Doppler ultrasound a highly reliable method for the study of this disorder. (Author) 18 refs

  1. Positron annihilation study of vacancy-type defects in fast-neutron-irradiated MgO·nAl{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Abu Zayed Mohammad Saliqur, E-mail: zayed82000@yahoo.com [Key Laboratory of Nuclear Analytical Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, 19B Yuquanlu Shijingshan District, Beijing 100049 (China); Li, Zhuoxin; Cao, Xingzhong; Wang, Baoyi; Wei, Long [Key Laboratory of Nuclear Analytical Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, 19B Yuquanlu Shijingshan District, Beijing 100049 (China); Xu, Qiu [Reactor Research Institute, Kyoto University 2, Asashiro-Nishi, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Atobe, Kozo [Nuclear Safety Technology Center, 9-15, 1-chome, Utsubohonmachi, Nishi Ku, Osaka 550-0004 (Japan)

    2014-09-15

    Highlights: •Detection of Al monovacancy by positron lifetime spectroscopy in fast neutron-irradiated MgO·nAl{sub 2}O{sub 3}(n=2). •Concentration of defects is also estimated for Al monovacancy. •O atom peak was observed by using coincidence Doppler broadening spectroscopy. -- Abstract: The positron lifetimes of fast-neutron-irradiated MgO·nAl{sub 2}O{sub 3} single crystals were measured to investigate the formation of cation vacancies. Al monovacancy was possibly observed in samples irradiated by fast neutrons at ultra-low temperatures. Additionally, vacancy-oxygen complex centers were possibly observed in samples irradiated at higher temperatures and fast neutron fluences. Coincidence Doppler broadening (CDB) spectra were measured to obtain information regarding the vicinity of vacancy-type defects. A peak at approximately 11 × 10{sup −3} m{sub 0}c was observed, which may be due to the presence of oxygen atoms in the neighborhood of the vacancies.

  2. Arm locking with Doppler estimation errors

    Energy Technology Data Exchange (ETDEWEB)

    Yu Yinan; Wand, Vinzenz; Mitryk, Shawn; Mueller, Guido, E-mail: yinan@phys.ufl.ed [Department of Physics, University of Florida, Gainesville, FL 32611 (United States)

    2010-05-01

    At the University of Florida we developed the University of Florida LISA Interferometer Simulator (UFLIS) in order to study LISA interferometry with hardware in the loop at a system level. One of the proposed laser frequency stabilization techniques in LISA is arm locking. Arm locking uses an adequately filtered linear combination of the LISA arm signals as a frequency reference. We will report about experiments in which we demonstrated arm locking using UFLIS. During these experiments we also discovered a problem associated with the Doppler shift of the return beam. The initial arm locking publications assumed that this Doppler shift can perfectly be subtracted inside the phasemeter or adds an insignificant offset to the sensor signal. However, the remaining Doppler knowledge error will cause a constant change in the laser frequency if unaccounted for. Several ways to circumvent this problem have been identified. We performed detailed simulations and started preliminary experiments to verify the performance of the proposed new controller designs.

  3. Low-Frequency Gravitational Wave Searches Using Spacecraft Doppler Tracking

    Directory of Open Access Journals (Sweden)

    Armstrong J. W.

    2006-01-01

    Full Text Available This paper discusses spacecraft Doppler tracking, the current-generation detector technology used in the low-frequency (~millihertz gravitational wave band. In the Doppler method the earth and a distant spacecraft act as free test masses with a ground-based precision Doppler tracking system continuously monitoring the earth-spacecraft relative dimensionless velocity $2 Delta v/c = Delta u/ u_0$, where $Delta u$ is the Doppler shift and $ u_0$ is the radio link carrier frequency. A gravitational wave having strain amplitude $h$ incident on the earth-spacecraft system causes perturbations of order $h$ in the time series of $Delta u/ u_0$. Unlike other detectors, the ~1-10 AU earth-spacecraft separation makes the detector large compared with millihertz-band gravitational wavelengths, and thus times-of-flight of signals and radio waves through the apparatus are important. A burst signal, for example, is time-resolved into a characteristic signature: three discrete events in the Doppler time series. I discuss here the principles of operation of this detector (emphasizing transfer functions of gravitational wave signals and the principal noises to the Doppler time series, some data analysis techniques, experiments to date, and illustrations of sensitivity and current detector performance. I conclude with a discussion of how gravitational wave sensitivity can be improved in the low-frequency band.

  4. Modeling streamflow from coupled airborne laser scanning and acoustic Doppler current profiler data

    Science.gov (United States)

    Norris, Lam; Kean, Jason W.; Lyon, Steve

    2016-01-01

    The rating curve enables the translation of water depth into stream discharge through a reference cross-section. This study investigates coupling national scale airborne laser scanning (ALS) and acoustic Doppler current profiler (ADCP) bathymetric survey data for generating stream rating curves. A digital terrain model was defined from these data and applied in a physically based 1-D hydraulic model to generate rating curves for a regularly monitored location in northern Sweden. Analysis of the ALS data showed that overestimation of the streambank elevation could be adjusted with a root mean square error (RMSE) block adjustment using a higher accuracy manual topographic survey. The results of our study demonstrate that the rating curve generated from the vertically corrected ALS data combined with ADCP data had lower errors (RMSE = 0.79 m3/s) than the empirical rating curve (RMSE = 1.13 m3/s) when compared to streamflow measurements. We consider these findings encouraging as hydrometric agencies can potentially leverage national-scale ALS and ADCP instrumentation to reduce the cost and effort required for maintaining and establishing rating curves at gauging station sites similar to the Röån River.

  5. Laser Doppler measurements in two-phase flows

    International Nuclear Information System (INIS)

    Durst, F.; Zare, M.

    1976-01-01

    Basic theory for laser-Doppler velocity measurements of large reflecting or refracting surfaces is provided. It is shown that the Doppler-signals contain information of the velocity and size of the large bodies, and relationships for transforming velocity and radius of curvature of moving spheres are presented. Preliminary experiments verified the analytical findings and demonstrated the applicability of the method to some two-phase flows

  6. Transversal Doppler-Fizeau effect

    International Nuclear Information System (INIS)

    Subacius, E.

    1981-01-01

    The relativistic calculation of the Doppler-Fizeau effect foresees a second grade redshift due to the proper time dilation of a moving object. The relevance of this relativistic effect on astrophysical observation is discussed, herein. (Auhor) [pt

  7. Operational Bright-Band Snow Level Detection Using Doppler Radar

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A method to detect the bright-band snow level from radar reflectivity and Doppler vertical velocity data collection with an atmospheric profiling Doppler radar. The...

  8. Distribution of Doppler Redshifts of Associated Absorbers of SDSS ...

    Indian Academy of Sciences (India)

    The authors searched all ... quasar, where the contribution of the Doppler motion is relatively small. ..... might contribute to the Doppler redshift distribution. 5. ... out accounting for the contamination of intervening absorption systems, which can.

  9. Settings and artefacts relevant for Doppler ultrasound in large vessel vasculitis

    DEFF Research Database (Denmark)

    Terslev, L; Diamantopoulos, A P; Døhn, U Møller

    2017-01-01

    Ultrasound is used increasingly for diagnosing large vessel vasculitis (LVV). The application of Doppler in LVV is very different from in arthritic conditions. This paper aims to explain the most important Doppler parameters, including spectral Doppler, and how the settings differ from those used...

  10. [Diagnostic value of power Doppler ultrasonography for Sirenomelia Seguence in prenatal].

    Science.gov (United States)

    Yan, Xia-yu; Yang, Tai-zhu; Luo, Hong; Tian, Yu; Yang, Fan

    2011-11-01

    To study and discuss the diagnostic value and ultrasonographic characteristics of power doppler ultrasound in the prenatal diagnosis of Sirenomelia Seguence. The abdominal aorta in two fetuses with sirenomelia seguence fetuses and in ten with nomal was reviewed and compared with two-dimensional power doppler ultrasound and three-dimensional power doppler ultrasound in prenatal. The abdominal aorta were showed to divid into renal arteries in the kidney level while two common iliac arteries in the pelvis in nomal fetuses with two-dimensional power doppler ultrasound and three-dimensional power doppler ultrasound; compared with the nomal, the abdominal aorta and whose branches in sirenomelia seguence were demonstrated as follows: 1) a large and deformed vascular coming from the high abdominal aorta, which was found to act as a umbilical artery by careful examination; 2) no bifurcation of renal arteries identified; 3) no bifurcation of two common iliac arteries identified; 4) the abdominal aorta changing into a narrow vascular after one deformed vascular separating from. Sirenomelia seguence fetuses has a characteristic change in two-dimensional power doppler ultrasound and three-dimensional power doppler ultrasound, which is helpful to improve the prenatal diagnosis of sirenomelia seguence.

  11. Doppler sonography of diabetic feet: Quantitative analysis of blood flow volume

    International Nuclear Information System (INIS)

    Seo, Young Lan; Kim, Ho Chul; Choi, Chul Soon; Yoon, Dae Young; Han, Dae Hee; Moon, Jeung Hee; Bae, Sang Hoon

    2002-01-01

    To analyze Doppler sonographic findings of diabetic feet by estimating the quantitative blood flow volume and by analyzing waveform on Doppler. Doppler sonography was performed in thirty four patients (10 diabetic patients with foot ulceration, 14 diabetic patients without ulceration and 10 normal patients as the normal control group) to measure the flow volume of the arteries of the lower extremities (posterior and anterior tibial arteries, and distal femoral artery. Analysis of doppler waveforms was also done to evaluate the nature of the changed blood flow volume of diabetic patients, and the waveforms were classified into triphasic, biphasic-1, biphasic-2 and monophasic patterns. Flow volume of arteries in diabetic patients with foot ulceration was increased witha statistical significance when compared to that of diabetes patients without foot ulceration of that of normal control group (P<0.05). Analysis of Doppler waveform revealed that the frequency of biphasic-2 pattern was significantly higher in diabetic patients than in normal control group(p<0.05). Doppler sonography in diabetic feet showed increased flow volume and biphasic Doppler waveform, and these findings suggest neuropathy rather than ischemic changes in diabetic feet.

  12. Doppler sonography of diabetic feet: Quantitative analysis of blood flow volume

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Young Lan; Kim, Ho Chul; Choi, Chul Soon; Yoon, Dae Young; Han, Dae Hee; Moon, Jeung Hee; Bae, Sang Hoon [Hallym University College of Medicine, Seoul (Korea, Republic of)

    2002-09-15

    To analyze Doppler sonographic findings of diabetic feet by estimating the quantitative blood flow volume and by analyzing waveform on Doppler. Doppler sonography was performed in thirty four patients (10 diabetic patients with foot ulceration, 14 diabetic patients without ulceration and 10 normal patients as the normal control group) to measure the flow volume of the arteries of the lower extremities (posterior and anterior tibial arteries, and distal femoral artery. Analysis of doppler waveforms was also done to evaluate the nature of the changed blood flow volume of diabetic patients, and the waveforms were classified into triphasic, biphasic-1, biphasic-2 and monophasic patterns. Flow volume of arteries in diabetic patients with foot ulceration was increased witha statistical significance when compared to that of diabetes patients without foot ulceration of that of normal control group (P<0.05). Analysis of Doppler waveform revealed that the frequency of biphasic-2 pattern was significantly higher in diabetic patients than in normal control group(p<0.05). Doppler sonography in diabetic feet showed increased flow volume and biphasic Doppler waveform, and these findings suggest neuropathy rather than ischemic changes in diabetic feet.

  13. Transesophageal color Doppler evaluation of obstructive lesions using the new "Quasar" technology.

    Science.gov (United States)

    Fan, P; Nanda, N C; Gatewood, R P; Cape, E G; Yoganathan, A P

    1995-01-01

    Due to the unavoidable problem of aliasing, color flow signals from high blood flow velocities cannot be measured directly by conventional color Doppler. A new technology termed Quantitative Un-Aliased Speed Algorithm Recognition (Quasar) has been developed to overcome this limitation. Employing this technology, we used transesophageal color Doppler echocardiography to investigate whether the velocities detected by the Quasar would correlate with those obtained by continuous-wave Doppler both in vitro and in vivo. In the in vitro study, a 5.0 MHz transesophageal transducer of a Kontron Sigma 44 color Doppler flow system was used. Fourteen different peak velocities calculated and recorded by color Doppler-guided continuous-wave Doppler were randomly selected. In the clinical study, intraoperative transesophageal echocardiography was performed using the same transducer 18 adults (13 aortic valve stenosis, 2 aortic and 2 mitral stenosis, 2 hypertrophic obstructive cardiomyopathy and 1 mitral valve stenosis). Following each continuous-wave Doppler measurement, the Quasar was activated, and a small Quasar marker was placed in the brightest area of the color flow jet to obtain the maximum mean velocity readout. The maximum mean velocities measured by Quasar closely correlated with maximum peak velocities obtained by color flow guided continuous-wave Doppler in both in vitro (0.53 to 1.65 m/s, r = 0.99) and in vivo studies (1.50 to 6.01 m/s, r = 0.97). We conclude that the new Quasar technology can accurately measure high blood flow velocities during transesophageal color Doppler echocardiography. This technique has the potential of obviating the need for continuous-wave Doppler.

  14. DOPPLER SIGNATURES OF THE ATMOSPHERIC CIRCULATION ON HOT JUPITERS

    International Nuclear Information System (INIS)

    Showman, Adam P.; Lewis, Nikole K.; Fortney, Jonathan J.; Shabram, Megan

    2013-01-01

    The meteorology of hot Jupiters has been characterized primarily with thermal measurements, but recent observations suggest the possibility of directly detecting the winds by observing the Doppler shift of spectral lines seen during transit. Motivated by these observations, we show how Doppler measurements can place powerful constraints on the meteorology. We show that the atmospheric circulation—and Doppler signature—of hot Jupiters splits into two regimes. Under weak stellar insolation, the day-night thermal forcing generates fast zonal jet streams from the interaction of atmospheric waves with the mean flow. In this regime, air along the terminator (as seen during transit) flows toward Earth in some regions and away from Earth in others, leading to a Doppler signature exhibiting superposed blueshifted and redshifted components. Under intense stellar insolation, however, the strong thermal forcing damps these planetary-scale waves, inhibiting their ability to generate jets. Strong frictional drag likewise damps these waves and inhibits jet formation. As a result, this second regime exhibits a circulation dominated by high-altitude, day-to-night airflow, leading to a predominantly blueshifted Doppler signature during transit. We present state-of-the-art circulation models including non-gray radiative transfer to quantify this regime shift and the resulting Doppler signatures; these models suggest that cool planets like GJ 436b lie in the first regime, HD 189733b is transitional, while planets hotter than HD 209458b lie in the second regime. Moreover, we show how the amplitude of the Doppler shifts constrains the strength of frictional drag in the upper atmospheres of hot Jupiters. If due to winds, the ∼2 km s –1 blueshift inferred on HD 209458b may require drag time constants as short as 10 4 -10 6 s, possibly the result of Lorentz-force braking on this planet's hot dayside.

  15. Doppler-musical instrument

    International Nuclear Information System (INIS)

    Sato, T.J.; Watanabe, N.

    2001-01-01

    We propose a possible ultra-high energy resolution backscattering spectrometer optimized to spallation neutron source. A combination of multi monochromator crystal and Doppler drive provides considerable neutron flux, together with the reasonable energy range -30 < E < 30 μeV, even when the ultra-high energy resolution of ΔE∼0.03 μeV is attained. (author)

  16. Doppler-musical instrument

    Energy Technology Data Exchange (ETDEWEB)

    Sato, T.J. [National Research Institute for Metals, Tsukuba, Ibaraki (Japan); Watanabe, N. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Shibata, K. [Institute for Materials Research, Tohoku Univ., Sendai, Miyagi (Japan)

    2001-03-01

    We propose a possible ultra-high energy resolution backscattering spectrometer optimized to spallation neutron source. A combination of multi monochromator crystal and Doppler drive provides considerable neutron flux, together with the reasonable energy range -30 < E < 30 {mu}eV, even when the ultra-high energy resolution of {delta}E{approx}0.03 {mu}eV is attained. (author)

  17. Trans-skull ultrasonic Doppler system aided by fuzzy logic

    Science.gov (United States)

    Hata, Yutaka; Nakamura, Masato; Yagi, Naomi; Ishikawa, Tomomoto

    2012-06-01

    This paper describes a trans-skull ultrasonic Doppler system for measuring the blood flow direction in brain under skull. In this system, we use an ultrasonic array probe with the center frequency of 1.0 MHz. The system determines the fuzzy degree of blood flow by Doppler Effect, thereby it locates blood vessel. This Doppler Effect is examined by the center of gravity shift of the frequency magnitudes. In in-vitro experiment, a cow bone was employed as the skull, and three silicon tubes were done as blood vessels, and bubble in water as blood. We received the ultrasonic waves through a protein, the skull and silicon tubes in order. In the system, fuzzy degrees are determined with respect to the Doppler shift, amplitude of the waves and attenuation of the tissues. The fuzzy degrees of bone and blood direction are calculated by them. The experimental results showed that the system successfully visualized the skull and flow direction, compared with the location and flow direction of the phantom. Thus, it detected the flow direction by Doppler Effect under skull, and automatically extracted the region of skull and blood vessel.

  18. Spectroscopic Doppler analysis for visible-light optical coherence tomography

    Science.gov (United States)

    Shu, Xiao; Liu, Wenzhong; Duan, Lian; Zhang, Hao F.

    2017-12-01

    Retinal oxygen metabolic rate can be effectively measured by visible-light optical coherence tomography (vis-OCT), which simultaneously quantifies oxygen saturation and blood flow rate in retinal vessels through spectroscopic analysis and Doppler measurement, respectively. Doppler OCT relates phase variation between sequential A-lines to the axial flow velocity of the scattering medium. The detectable phase shift is between -π and π due to its periodicity, which limits the maximum measurable unambiguous velocity without phase unwrapping. Using shorter wavelengths, vis-OCT is more vulnerable to phase ambiguity since flow induced phase variation is linearly related to the center wavenumber of the probing light. We eliminated the need for phase unwrapping using spectroscopic Doppler analysis. We split the whole vis-OCT spectrum into a series of narrow subbands and reconstructed vis-OCT images to extract corresponding Doppler phase shifts in all the subbands. Then, we quantified flow velocity by analyzing subband-dependent phase shift using linear regression. In the phantom experiment, we showed that spectroscopic Doppler analysis extended the measurable absolute phase shift range without conducting phase unwrapping. We also tested this method to quantify retinal blood flow in rodents in vivo.

  19. A study of doppler waveform using pulsatile flow model

    International Nuclear Information System (INIS)

    Chung, Hye Won; Chung, Myung Jin; Park, Jae Hyung; Chung, Jin Wook; Lee, Dong Hyuk; Min, Byoung Goo

    1997-01-01

    Through the construction of a pulsatile flow model using an artificial heart pump and stenosis to demonstrate triphasic Doppler waveform, which simulates in vivo conditions, and to evaluate the relationship between Doppler waveform and vascular compliance. The flow model was constructed using a flowmeter, rubber tube, glass tube with stenosis, and artificial heart pump. Doppler study was carried out at the prestenotic, poststenotic, and distal segments;compliance was changed by changing the length of the rubber tube. With increasing proximal compliance, Doppler waveforms show decreasing peak velocity of the first phase and slightly delayed acceleration time, but the waveform itself did not change significantly. Distal compliance influenced the second phase, and was important for the formation of pulsus tardus and parvus, which without poststenotic vascular compliance, did not develop. The peak velocity of the first phase was inversely proportional to proximal compliance, and those of the second and third phases were directly proportional to distal compliance. After constructing this pulsatile flow model, we were able to explain the relationship between vascular compliance and Doppler waveform, and also better understand the formation of pulsus tardus and parvus

  20. Response of a Doppler canceling system to plane gravitational waves

    International Nuclear Information System (INIS)

    Caporali, A.

    1982-01-01

    This paper discusses the interaction of long periodic gravitational waves with a three-link microwave system known as the Doppler canceling system. This system, which was developed for gravitational red-shift experiment, uses one-way and two-way Doppler information to construct the beat signal of two reference oscillators moving with respect to each other. The geometric-optics approximation is used to derive the frequency shift produced on a light signal propagating in a gravitational-wave space-time. The signature left on the Doppler-canceled beat by bursts and continuous gravitational waves is analyzed. A comparison is made between the response to gravitational waves of the Doppler canceling system and that of a (NASA) Doppler tracking system which employs two-way, round-trip radio waves. A threefold repetition of the gravitational wave form is found to be a common feature of the response functions of both systems. These two functions otherwise exhibit interesting differences

  1. Micro-Doppler Ambiguity Resolution Based on Short-Time Compressed Sensing

    Directory of Open Access Journals (Sweden)

    Jing-bo Zhuang

    2015-01-01

    Full Text Available When using a long range radar (LRR to track a target with micromotion, the micro-Doppler embodied in the radar echoes may suffer from ambiguity problem. In this paper, we propose a novel method based on compressed sensing (CS to solve micro-Doppler ambiguity. According to the RIP requirement, a sparse probing pulse train with its transmitting time random is designed. After matched filtering, the slow-time echo signals of the micromotion target can be viewed as randomly sparse sampling of Doppler spectrum. Select several successive pulses to form a short-time window and the CS sensing matrix can be built according to the time stamps of these pulses. Then performing Orthogonal Matching Pursuit (OMP, the unambiguous micro-Doppler spectrum can be obtained. The proposed algorithm is verified using the echo signals generated according to the theoretical model and the signals with micro-Doppler signature produced using the commercial electromagnetic simulation software FEKO.

  2. Korea-China Joint R and D on Doppler Lidar Technology

    International Nuclear Information System (INIS)

    Cha, Hyung Ki; Kim, D. H.; Kwon, S. O.; Yang, K. H.; Song, I. K.

    2009-03-01

    Doppler lidar technology is to monitor atmospheric wind velocity by measuring the light scattering signals between a laser and aerosol particles or molecules existing in the atmosphere. When the particles (or molecules) in the atmosphere are moving by wind force, the frequency of backscattering light is shifted by doppler effect, so that the wind velocity profile can be obtained by measurement of the shifted frequencies. When the laser radiation is scanned in four different direction, three dimensional wind profiles are obtained. The Anhui Institute of Optics and Fine Mechanics under the China Academy of Sciences has developed and operated the doppler lidar system for long time. In this project we want to developed a new technologies adopted to the chinese doppler system and to test the updated In the process of collaboration between China and Korea research teams, we want to learn the state-of-art technology involved in the doppler lidar system

  3. The effectiveness of Doppler controlled hemorrhoidal artery ligation ...

    African Journals Online (AJOL)

    In this work, we discuss the preliminary results of the effectiveness of the hemorrhoidal artery ligation under control Doppler as a new technique for the treatment of hemorrhoids. We report the results of patients with hemorrhoids we have followed over a period of one year who were treated with HAL Doppler. The intra-and ...

  4. Doppler ultrasonography of the lower extremity arteries: anatomy and scanning guidelines

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Ji Young [Dept. of Radiology, Ewha Womans University School of Medicine, Seoul (Korea, Republic of)

    2017-04-15

    Doppler ultrasonography of the lower extremity arteries is a valuable technique, although it is less frequently indicated for peripheral arterial disease than for deep vein thrombosis or varicose veins. Ultrasonography can diagnose stenosis through the direct visualization of plaques and through the analysis of the Doppler waveforms in stenotic and poststenotic arteries. To perform Doppler ultrasonography of the lower extremity arteries, the operator should be familiar with the arterial anatomy of the lower extremities, basic scanning techniques, and the parameters used in color and pulsed-wave Doppler ultrasonography.

  5. Doppler ultrasonography of the lower extremity arteries: anatomy and scanning guidelines

    Directory of Open Access Journals (Sweden)

    Ji Young Hwang

    2017-04-01

    Full Text Available Doppler ultrasonography of the lower extremity arteries is a valuable technique, although it is less frequently indicated for peripheral arterial disease than for deep vein thrombosis or varicose veins. Ultrasonography can diagnose stenosis through the direct visualization of plaques and through the analysis of the Doppler waveforms in stenotic and poststenotic arteries. To perform Doppler ultrasonography of the lower extremity arteries, the operator should be familiar with the arterial anatomy of the lower extremities, basic scanning techniques, and the parameters used in color and pulsed-wave Doppler ultrasonography.

  6. ISAR imaging using the instantaneous range instantaneous Doppler method

    CSIR Research Space (South Africa)

    Wazna, TM

    2015-10-01

    Full Text Available In Inverse Synthetic Aperture Radar (ISAR) imaging, the Range Instantaneous Doppler (RID) method is used to compensate for the nonuniform rotational motion of the target that degrades the Doppler resolution of the ISAR image. The Instantaneous Range...

  7. Scanning laser Doppler vibrometry

    DEFF Research Database (Denmark)

    Brøns, Marie; Thomsen, Jon Juel

    With a Scanning Laser Doppler Vibrometer (SLDV) a vibrating surface is automatically scanned over predefined grid points, and data processed for displaying vibration properties like mode shapes, natural frequencies, damping ratios, and operational deflection shapes. Our SLDV – a PSV-500H from...

  8. Avaliação ultra-sonográfica e ao Doppler dos TIPS (anastomose portossistêmica intra-hepática transjugular

    Directory of Open Access Journals (Sweden)

    Machado Márcio Martins

    2004-01-01

    Full Text Available A anastomose portossistêmica intra-hepática transjugular (TIPS compreende a técnica mais recente e mais popular para o alívio da hipertensão portal sintomática, especialmente para os casos com varizes e hemorragia digestiva alta, e menos comumente para o tratamento da ascite refratária. Os TIPS podem apresentar complicações após sua colocação, como as estenoses e oclusões. A ultra-sonografia e o Doppler permitem o estudo dos TIPS de uma forma não invasiva. Neste artigo os autores relatam os achados recentes à ultra-sonografia e ao Doppler nos casos de funcionamento normal e anormal (estenoses/oclusões dos TIPS.

  9. Three-dimensional power Doppler sonography in screening for carotid artery disease.

    Science.gov (United States)

    Keberle, M; Jenett, M; Beissert, M; Jahns, R; Haerten, R; Hahn, D

    2000-01-01

    Color Doppler sonography has gained considerable recognition as a noninvasive method to detect carotid artery disease and to assess the degree of carotid artery stenosis. However, results are highly operator-dependent and cannot be presented as survey images. The purpose of this study was to evaluate real-time 3-dimensional (3D) power Doppler sonography as a method for screening for atherosclerosis in the carotid arteries. We prospectively screened 75 patients for carotid artery disease using both conventional color Doppler sonography and 3D power Doppler sonography, and the results from the 2 modalities were compared. A total of 150 common carotid arteries, 150 internal carotid arteries, and 150 external carotid arteries were examined utilizing a 7.5-MHz linear-array transducer combined with tissue harmonic imaging. Color Doppler sonography detected 297 normal or atherosclerotic arteries without stenosis, 57 arteries with mild (1-49%) stenosis, 41 with moderate (50-69%) stenosis, 32 with severe (70-99%) stenosis, and 9 with occlusions. The degree of stenosis determined by color Doppler sonography correlated with that determined by 3D power Doppler sonography (r = 0.982-0.998). Moreover, there was a good correlation between the measurements for both the length of the lesion and its distance from the bulb as determined by the 3D volume surveys and by color Doppler sonography (r = 0.986). The interobserver variability rate was 3.7% +/- 0.5%. Generally, the acquisition and reconstruction of the 3D data took less than 5 minutes. 3D power Doppler sonography is easy to perform and is an accurate method in screening for atherosclerotic lesions of the carotid arteries. Moreover, it provides excellent 3D volume surveys that may be helpful in the planning of surgical treatment. Copyright 2000 John Wiley & Sons, Inc.

  10. Doppler electron velocimetry : notes on creating a practical tool.

    Energy Technology Data Exchange (ETDEWEB)

    Reu, Phillip L.; Milster, Tom (University of Arizona)

    2008-11-01

    The Doppler electron velocimeter (DEV) has been shown to be theoretically possible. This report attempts to answer the next logical question: Is it a practical instrument? The answer hinges upon whether enough electrons are available to create a time-varying Doppler current to be measured by a detector with enough sensitivity and bandwidth. The answer to both of these questions is a qualified yes. A target Doppler frequency of 1 MHz was set as a minimum rate of interest. At this target a theoretical beam current signal-to-noise ratio of 25-to-1 is shown for existing electron holography equipment. A detector is also demonstrated with a bandwidth of 1-MHz at a current of 10 pA. Additionally, a Linnik-type interferometer that would increase the available beam current is shown that would offer a more flexible arrangement for Doppler electron measurements over the traditional biprism.

  11. Micro-Doppler classification of riders and riderless horses

    Science.gov (United States)

    Tahmoush, David

    2014-05-01

    Micro-range Micro-Doppler can be used to isolate particular parts of the radar signature, and in this case we demonstrate the differences in the signature between a walking horse versus a walking horse with a rider. Using micro-range micro-Doppler, we can distinguish the radar returns from the rider as separate from the radar returns of the horse.

  12. Color Doppler flow mapping of stenotic and regurgitant natural heart valves

    International Nuclear Information System (INIS)

    Nanda, N.C.

    1986-01-01

    Color Doppler echocardiography has found widest application in reliable detection and assessment of severity of both atrio-ventricular and semi-lunar valve incompetence. The authors believe both the sensitivity and specificity of color Doppler for the detection of mitral and aortic regurgitation is very high in patients with adequate acoustic windows. In 82 patients with proven mitral regurgitation studied, the best correlations with angiography were noted when the maximum or average regurgitant jet are obtained by color Doppler from three standard 2-D echo planes (parasternal long and short axis and apical four chamber view) and expressed as a percentage of the left atrial area were considered. The criteria the authors used for assessment of tricuspid and pulmonary valve incompetence are similar to those used for mitral and aortic valve incompetence, but the lack of a good ''gold'' standard has hampered validation. The color Doppler technique also supplements conventional Doppler in the assessment of severity of stenotic lesions by facilitating parallel alignment of the continuous wave Doppler cursor line with the stenotic jet for accurate recording of maximal velocities and pressure gradients. The authors have found this method especially useful in the assessment of aortic stenosis. In conclusion, color Doppler flow mapping combined with conventional echocardiography provides, for the first time, a comprehensive noninvasive assessement of the severity of regurgitant and stenotic lesions

  13. Comparison of the Diagnostic Performance of Power Doppler Ultrasound and a New Microvascular Doppler Ultrasound Technique (AngioPLUS) for Differentiating Benign and Malignant Breast Masses.

    Science.gov (United States)

    Jung, Hae Kyoung; Park, Ah Young; Ko, Kyung Hee; Koh, Jieun

    2018-03-12

    This study was performed to compare the diagnostic performance of power Doppler ultrasound (US) and a new microvascular Doppler US technique (AngioPLUS; SuperSonic Imagine, Aix-en-Provence, France) for differentiating benign and malignant breast masses. Power Doppler US and AngioPLUS findings were available in 124 breast masses with confirmed pathologic results (benign, 80 [64.5%]; malignant, 44 [35.5%]). The diagnostic performance of each tool was calculated to distinguish benign from malignant masses using a receiver operating characteristic curve analysis and compared. The area under the curve showed that AngioPLUS was superior to power Doppler US in differentiating benign from malignant breast masses, but the difference was not statistically significant. © 2018 by the American Institute of Ultrasound in Medicine.

  14. Aplicação da ultrassonografia colorida doppler em programas de transferência de embriões equinos Potential use of doppler ultrasound in equine embryo transfer programs

    Directory of Open Access Journals (Sweden)

    Jair Camargo Ferreira

    2011-06-01

    Full Text Available Os programas comerciais de transferência de embriões em éguas existem por mais de três décadas e são hoje uma das biotécnias mais utilizadas na reprodução assistida de equinos. O exame ultrassonográfico nos períodos pré e pós-cobertura de doadoras de embriões, assim como a avaliação de receptoras no momento da inovulação é de vital importância para o êxito de um programa de transferência de embriões. A ultrassonografia Doppler é uma técnica não-invasiva que permite a avaliação em tempo real da hemodinâmica do trato reprodutivo de animais de grande porte. Por fornecer detalhes anatômicos e informações imediatas sobre a fisiologia do fluxo sanguíneo de tecidos e órgãos, o exame doppler permite a avaliação do potencial ovulatório de folículos e do status funcional de corpo lúteo e útero, além de ser uma técnica auxiliar para o diagnóstico de distúrbios na hemodinâmica do sistema reprodutivo. Alterações na perfusão sanguínea dos futuros folículos dominantes são detectáveis em diferentes fases de seu desenvolvimento, como na divergência folicular e no período pré-ovulatório. A partir dessas informações, é possível determinar o princípio da atividade sexual e o momento ideal para o início de tratamentos superovulatórios e indutores de ovulação, assim como o momento mais apropriado para a realização de coberturas de éguas doadoras de embriões. A avaliação através do modo-Doppler do corpo lúteo e útero de éguas receptoras é também um instrumento auxiliar para a seleção de animais com perfil sérico de progesterona e ambiente uterino adequados para a sobrevivência do embrião e manutenção da gestação. Essa técnica pode ser útil ainda ao se avaliar a interação concepto-maternal. Apesar da aplicabilidade da tecnologia doppler dentro de programas de transferência de embriões, novos estudos visando a determinar padrões de normalidade e posterior caracterização de

  15. Acute Effects of Lateral Thigh Foam Rolling on Arterial Tissue Perfusion Determined by Spectral Doppler and Power Doppler Ultrasound.

    Science.gov (United States)

    Hotfiel, Thilo; Swoboda, Bernd; Krinner, Sebastian; Grim, Casper; Engelhardt, Martin; Uder, Michael; Heiss, Rafael U

    2017-04-01

    Hotfiel, T, Swoboda, B, Krinner, S, Grim, C, Engelhardt, M, Uder, M, and Heiss, R. Acute effects of lateral thigh foam rolling on arterial tissue perfusion determined by spectral Doppler and power Doppler ultrasound. J Strength Cond Res 31(4): 893-900, 2017-Foam rolling has been developed as a popular intervention in training and rehabilitation. However, evidence on its effects on the cellular and physiological level is lacking. The aim of this study was to assess the effect of foam rolling on arterial blood flow of the lateral thigh. Twenty-one healthy participants (age, 25 ± 2 years; height, 177 ± 9 cm; body weight, 74 ± 9 kg) were recruited from the medical and sports faculty. Arterial tissue perfusion was determined by spectral Doppler and power Doppler ultrasound, represented as peak flow (Vmax), time average velocity maximum (TAMx), time average velocity mean (TAMn), and resistive index (RI), and with semiquantitative grading that was assessed by 4 blindfolded investigators. Measurement values were assessed under resting conditions and twice after foam rolling exercises of the lateral thigh (0 and 30 minutes after intervention). The trochanteric region, mid portion, and distal tibial insertion of the lateral thigh were representative for data analysis. Arterial blood flow of the lateral thigh increased significantly after foam rolling exercises compared with baseline (p ≤ 0.05). We detected a relative increase in Vmax of 73.6% (0 minutes) and 52.7% (30 minutes) (p power Doppler scores at all portions revealed increased average grading of 1.96 after intervention and 2.04 after 30 minutes compared with 0.75 at baseline. Our results may contribute to the understanding of local physiological reactions to self-myofascial release.

  16. 21 CFR 892.1550 - Ultrasonic pulsed doppler imaging system.

    Science.gov (United States)

    2010-04-01

    ... system. (a) Identification. An ultrasonic pulsed doppler imaging system is a device that combines the... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ultrasonic pulsed doppler imaging system. 892.1550... include signal analysis and display equipment, patient and equipment supports, component parts, and...

  17. Coherent optical transients observed in rubidium atomic line filtered Doppler velocimetry experiments

    Energy Technology Data Exchange (ETDEWEB)

    Fajardo, Mario E., E-mail: mario.fajardo@eglin.af.mil; Molek, Christopher D.; Vesely, Annamaria L. [Air Force Research Laboratory, Munitions Directorate, Ordnance Division, Energetic Materials Branch, AFRL/RWME, 2306 Perimeter Road, Eglin AFB, Florida 32542-5910 (United States)

    2015-10-14

    We report the first successful results from our novel Rubidium Atomic Line Filtered (RALF) Doppler velocimetry apparatus, along with unanticipated oscillatory signals due to coherent optical transients generated within pure Rb vapor cells. RALF is a high-velocity and high-acceleration extension of the well-known Doppler Global Velocimetry (DGV) technique for constructing multi-dimensional flow velocity vector maps in aerodynamics experiments [H. Komine, U.S. Patent No. 4,919,536 (24 April 1990)]. RALF exploits the frequency dependence of pressure-broadened Rb atom optical absorptions in a heated Rb/N{sub 2} gas cell to encode the Doppler shift of reflected near-resonant (λ{sub 0} ≈ 780.24 nm) laser light onto the intensity transmitted by the cell. The present RALF apparatus combines fiber optic and free-space components and was built to determine suitable operating conditions and performance parameters for the Rb/N{sub 2} gas cells. It yields single-spot velocities of thin laser-driven-flyer test surfaces and incorporates a simultaneous Photonic Doppler Velocimetry (PDV) channel [Strand et al., Rev. Sci. Instrum. 77, 083108 (2006)] for validation of the RALF results, which we demonstrate here over the v = 0 to 1 km/s range. Both RALF and DGV presume the vapor cells to be simple Beer's Law optical absorbers, so we were quite surprised to observe oscillatory signals in experiments employing low pressure pure Rb vapor cells. We interpret these oscillations as interference between the Doppler shifted reflected light and the Free Induction Decay (FID) coherent optical transient produced within the pure Rb cells at the original laser frequency; this is confirmed by direct comparison of the PDV and FID signals. We attribute the different behaviors of the Rb/N{sub 2} vs. Rb gas cells to efficient dephasing of the atomic/optical coherences by Rb-N{sub 2} collisions. The minimum necessary N{sub 2} buffer gas density ≈0.3 amagat translates into a

  18. Noise Studies of Externally Dispersed Interferometry for Doppler Velocimetry

    International Nuclear Information System (INIS)

    Erskine, D J; Edelstein, J; Lloyd, J; Muirhead, P

    2006-01-01

    Externally Dispersed Interferometry (EDI) is the series combination of a fixed-delay field-widened Michelson interferometer with a dispersive spectrograph. This combination boosts the spectrograph performance for both Doppler velocimetry and high resolution spectroscopy. The interferometer creates a periodic comb that multiplies against the input spectrum to create moire fringes, which are recorded in combination with the regular spectrum. Both regular and high-frequency spectral components can be recovered from the data--the moire component carries additional information that increases the signal to noise for velocimetry and spectroscopy. Here we present simulations and theoretical studies of the photon limited Doppler velocity noise in an EDI. We used a model spectrum of a 1600K temperature star. For several rotational blurring velocities 0, 7.5, 15 and 25 km/s we calculated the dimensionless Doppler quality index (Q) versus wavenumber v. This is the normalized RMS of the derivative of the spectrum and is proportional to the photon-limited Doppler signal to noise ratio

  19. Monolayer dispersion of CoO on Al2O3 probed by positronium atom

    International Nuclear Information System (INIS)

    Liu, Z.W.; Zhang, H.J.; Chen, Z.Q.

    2014-01-01

    CoO/Al 2 O 3 catalysts were prepared by wet impregnation method with CoO contents ranging from 0 wt% to 24 wt%. X-ray diffraction and X-ray photoelectron spectroscopy measurements suggest formation of CoO after calcined in N 2 . Quantitative X-ray diffraction analysis indicates monolayer dispersion capacity of CoO in CoO/Al 2 O 3 catalysts to be about 3 wt%. Positron annihilation lifetime and coincidence Doppler broadening measurements were performed to study the dispersion state of CoO on Al 2 O 3 . The positron lifetime measurements reveal two long lifetime components τ 3 and τ 4 , which correspond to ortho-positronium annihilation lifetime in microvoids and large pores, respectively. It was found that the positronium atom is very sensitive to the dispersion state of CoO on Al 2 O 3 . The presence of CoO significantly decreases both the lifetime and the intensity of τ 4 . Detailed analysis of the coincidence Doppler broadening measurements suggests that with the CoO content lower than the monolayer dispersion, spin conversion reaction of positronium is induced by CoO. When the cobalt content is higher than the monolayer dispersion capacity, inhibition of positronium formation becomes the dominate effect.

  20. Applications of Doppler in the first trimester

    International Nuclear Information System (INIS)

    Taylor, K.J.W.; Ramirez, B.; Grannum, P.

    1986-01-01

    Fifty patients have been studied by duplex Doppler US imaging in the first trimester. In normal gestations, luteal flow, characterized by a low pulsatility index (PI), can be seen in at least one ovary. Failure to detect luteal flow indicates a nonviable pregnancy. Six ectopic pregnancies demonstrated luteal flow and extrauterine heartbeat, detected by Doppler US. High PI values in the uterine artery are seen in the first trimester. Low PI values in the uterine arteries were found in patients with trophoblastic disease

  1. Christian Andreas Doppler--the man and his legacy.

    Science.gov (United States)

    Coman, I M

    2005-01-01

    Reminding the life and legacy of the Austrian Scientist who discovered the famous 'Doppler Effect'. C.A. Doppler was born the 29th of November 1803 in Salzburg. After studies in Linz and Vienna, he graduated in mathematics, became assistant at the University and later worked as a professor in Prague. Back to Vienna, he was appointed as professor at the Polytechnic School and --in 1850--as first director of the new Institute of Physics. C.A. Doppler did publish on magnetism, electricity, optics, and astronomy. He remains in the history of science due to the discovery presented (May 25, 1842) at the Royal Bohemian Society of Science entitled "On the colored light of the double stars and certain other stars of the heavens"; the paper described (applied to light) the shift of frequency which bears nowadays his name. The theory was later experimentally proven and--extended for any electromagnetic and acoustic waves--got myriads if applications in astronomy, physics, aviation, meteorology, and health science. Satomura in Japan (1955) published it's first ultrasound vascular application--with successive achievements in the next decades. Doppler ultrasonagraphy became the main noninvasive instrument for functional assesment of heart and vessels.

  2. Fetal Cardiac Doppler Signal Processing Techniques: Challenges and Future Research Directions

    Directory of Open Access Journals (Sweden)

    Saeed Abdulrahman Alnuaimi

    2017-12-01

    Full Text Available The fetal Doppler Ultrasound (DUS is commonly used for monitoring fetal heart rate and can also be used for identifying the event timings of fetal cardiac valve motions. In early-stage fetuses, the detected Doppler signal suffers from noise and signal loss due to the fetal movements and changing fetal location during the measurement procedure. The fetal cardiac intervals, which can be estimated by measuring the fetal cardiac event timings, are the most important markers of fetal development and well-being. To advance DUS-based fetal monitoring methods, several powerful and well-advanced signal processing and machine learning methods have recently been developed. This review provides an overview of the existing techniques used in fetal cardiac activity monitoring and a comprehensive survey on fetal cardiac Doppler signal processing frameworks. The review is structured with a focus on their shortcomings and advantages, which helps in understanding fetal Doppler cardiogram signal processing methods and the related Doppler signal analysis procedures by providing valuable clinical information. Finally, a set of recommendations are suggested for future research directions and the use of fetal cardiac Doppler signal analysis, processing, and modeling to address the underlying challenges.

  3. Doppler sonographic evaluation of ophthalmic arterial flow pattern in hypertensive patients

    International Nuclear Information System (INIS)

    Ryu, Dae Sik; Kim, Young Goo

    1994-01-01

    To compare the Doppler velocity waveform pattern of ophthalmic artery of hypertensive patients with that of normotensive subjects. Doppler velocity waveform was obtained from ophthalmic artery in 45 hypertensive patients and 60 normotensive subjects. Both hypertensives and normotensive subjects were classified according to age into those younger than and those older than 45 years. Doppler indices(pulsatility index(PI), resistance index(RI), the first systolic peak/the second systolic peak(S1/S2), the first systolic peak/diastolic peak(S1/D)) measured in hypertensive patients were compared with normotensive subjects. Among the various doppler indices, only S1/S2 showed significant difference(P < 0.05) between the hypertensive patients and normotensive subjects younger than 45 years. Doppler velocity waveform of hypertensive patients older than 45 years showed no significant difference from that of normotensive subjects with corresponding age. Doppler velocity waveform of ophthalmic artery in hypertensive patients younger than 45 years shows pattern with S2 higher than that of normotensive subjects. High S2 component(reflective-wave) may represent increased vascular impedance due to vasococonstriction of retinal arterioles in hypertensive patients

  4. Magnetic angioresonance of the carotid artery: correlation with color Doppler ultrasound

    International Nuclear Information System (INIS)

    Cotilla, J.; Miralles, M.; Cairols, M.C.; Dolz, J.L.; Vilanova, J.C.; Capdevila, A.

    1998-01-01

    To determine the value of magnetic angioresonance (MAR) in grading carotid stenosis, comparing it with color Doppler and intraarterial digital subtraction angiography (IADSA). A comparative study using color Doppler and MAR was carried out in 84 patients with coratid lesions. Fifty-two of the patients underwent angiographic study as well. The comparison of MAR versus arteriography in discriminating stenosis of more than 70%, expressed in terms of sensitivity specificity, overall precision and the kappa concordance index, gave values of 87.2, 90.8, 89.4 and 0.78%, respectively. When MAR was compared with color Doppler, the results were 86.8, 85.9, 86.3 and 0.72%, respectively. The results of the comparison between color Doppler and arteriography were 82.2, 86.2, 84.6 and 0.68%, respectively. The better correlation of MAR, as compares with angiography and color Doppler, with the grade of carotid stenosis indicates the high degree of reliability. The better correlation of MAR, as compares with angiography and color Doppler, with the grade of carotid stenosis indicates the high degree of reliability of this imaging technique. (Author) 29 refs

  5. Use of TRIGA-pulsed irradiations for high-temperature Doppler measurements

    Energy Technology Data Exchange (ETDEWEB)

    Foell, W K; Cashwell, R J; Bhattacharyya, S K [Argonne National Laboratory, Argonne, IL (United States); Russell, G J [Los Alamos Scientific Laboratory, University of California, Los Alamos, NM (United States)

    1974-07-01

    Conventional activation and reactivity measurements of the nuclear Doppler Effect have been limited to temperatures of about 2000{sup o}K because of problems with furnace equipment. There is a need for Doppler data at higher temperatures for design of reactors and analysis of reactor accidents. To fill this need, a novel technique using pulsed-mode operation of a TRIGA reactor has been developed at the University of Wisconsin. This new method, the Pulsed Activation Doppler (PAD) technique, has been used successfully for high temperature Doppler measurements of UO{sub 2} fuel pellets. In the PAD technique, UO{sub 2} test pellets were doped with varying amounts of U-235, with fissile enrichments varying from 0.22% to 12% by weight. The pellets were encapsulated in individual irradiation cells and electrically preheated to predetermined temperatures. Pyrofoam-graphite heaters were used to give preheat temperatures of up to 1720 deg. K. The cells were then positioned in the University of Wisconsin TRIGA reactor core and pulse-irradiated. During the rapid irradiation, adiabatic fission energy deposition occurred in the pellets and very high temperatures (over 3115 deg, K) were attained. Corresponding resonance neutron captures occurred at the elevated temperatures. The Doppler Ratio was deduced from the gamma activities of the Np-239 in the heated and unheated reference pellets. UO{sub 2} pellets of two nominal diameters, 210 mils (a surface-to-mass ratio, s/m = 1.1 cm{sup 2} /gm) and 360 mils (s/m = 0.63 cm{sup 2}/gm), were used for the experiments. For the 210 mil diameter pellets there was very good agreement between experimental results and Doppler ratios predicted both from extrapolations of the Hellstrand low-temperature resonance integral correlations and from GAROL calculations. Significantly, the agreement was good even for those pellets which experienced extensive melting. For the 360 mil diameter pellets the theoretical predictions were 10-15% lower than

  6. Doppler ultrasound scan during normal gestation: umbilical circulation

    International Nuclear Information System (INIS)

    Ruiz, T.; Sabate, J.; Martinez-Benavides, M. M.; Sanchez-Ramos, J.

    2002-01-01

    To determine normal umbilical circulation patterns by means of Doppler ultrasound scan in a healthy gestating population without risk factors and with normal perinatal results, and to evaluate any occurring modifications relative to gestational age by obtaining records kept during pregnancy. One hundred and sixteen pregnant women carrying a single fetus have been studied. These women had no risk factors, with both clinical and analytical controls, as well as ultrasound scans, all being normal. There were performed a total of 193 Doppler ultrasound scans between weeks 15 and 41 of gestation, with blood-flow analysis in the arteries and vein of the umbilical cord. The obtained information was correlated with parameters that evaluate fetal well-being (fetal monitoring and/or oxytocin test) and perinatal result (delivery type, birth weight, Apgar score). Statistical analysis was performed with the programs SPSS 6.0.1 for Windows and EPIINFO 6.0.4. With pulsed Doppler, the umbilical artery in all cases demonstrated a biphasic morphology with systolic and diastolic components and without retrograde blood flow. As the gestation period increased, there was observed a progressive decrease in resistance along with an increase in blood-flow velocity during the diastolic phase. The Doppler ultrasound scan is a non-invasive method that permits the hemodynamic study of umbilical blood circulation. A knowledge of normal blood-flow signal morphology, as well as of the normal values for Doppler indices in relation to gestational age would permit us to utilize this method in high-risk pregnancies. (Author) 30 refs

  7. Dispersed single-phase-step Michelson interferometer for Doppler imaging using sunlight.

    Science.gov (United States)

    Wan, Xiaoke; Ge, Jian

    2012-09-15

    A Michelson interferometer is dispersed with a fiber array-fed spectrograph, providing 59 Doppler sensing channels using sunlight in the 510-570 nm wavelength region. The interferometer operates at a single-phase-step mode, which is particularly advantageous in multiplexing and data processing compared to the phase-stepping mode of other interferometer spectrometer instruments. Spectral templates are prepared using a standard solar spectrum and simulated interferometer modulations, such that the correlation function with a measured 1D spectrum determines the Doppler shift. Doppler imaging of a rotating cylinder is demonstrated. The average Doppler sensitivity is ~12 m/s, with some channels reaching ~5 m/s.

  8. An elementary approach to the gravitational Doppler shift

    International Nuclear Information System (INIS)

    Wörner, C H; Rojas, Roberto

    2017-01-01

    In college physics courses, treatment of the Doppler effect is usually done far from the first introduction to kinematics. This paper aims to apply a graphical treatment to describe the gravitational redshift, by considering the Doppler effect in two accelerated reference frames and exercising the equivalence principle. This approach seems appropriate to discuss with beginner students and could serve to enrich the didactic processes. (paper)

  9. Magnetic Doppler imaging considering atmospheric structure modifications due to local abundances: a luxury or a necessity?

    Science.gov (United States)

    Kochukhov, O.; Wade, G. A.; Shulyak, D.

    2012-04-01

    Magnetic Doppler imaging is currently the most powerful method of interpreting high-resolution spectropolarimetric observations of stars. This technique has provided the very first maps of stellar magnetic field topologies reconstructed from time series of full Stokes vector spectra, revealing the presence of small-scale magnetic fields on the surfaces of Ap stars. These studies were recently criticised by Stift et al., who claimed that magnetic inversions are not robust and are seriously undermined by neglecting a feedback on the Stokes line profiles from the local atmospheric structure in the regions of enhanced metal abundance. We show that Stift et al. misinterpreted published magnetic Doppler imaging results and consistently neglected some of the most fundamental principles behind magnetic mapping. Using state-of-the-art opacity sampling model atmosphere and polarized radiative transfer codes, we demonstrate that the variation of atmospheric structure across the surface of a star with chemical spots affects the local continuum intensity but is negligible for the normalized local Stokes profiles except for the rare situation of a very strong line in an extremely Fe-rich atmosphere. For the disc-integrated spectra of an Ap star with extreme abundance variations, we find that the assumption of a mean model atmosphere leads to moderate errors in Stokes I but is negligible for the circular and linear polarization spectra. Employing a new magnetic inversion code, which incorporates the horizontal variation of atmospheric structure induced by chemical spots, we reconstructed new maps of magnetic field and Fe abundance for the bright Ap star α2 CVn. The resulting distribution of chemical spots changes insignificantly compared to the previous modelling based on a single model atmosphere, while the magnetic field geometry does not change at all. This shows that the assertions by Stift et al. are exaggerated as a consequence of unreasonable assumptions and

  10. Ultrasound and Doppler examination capabilities in adult portal hypertension type definition

    Directory of Open Access Journals (Sweden)

    N. V. Tumanskaya

    2015-08-01

    Full Text Available Early portal hypertension type diagnostics is an ultimate factor concerning kind and tactics of treatment. Aim. To objectify ultrasound examination capabilities, portal hemodynamics were studied in 97 patients using impulse and color doppler. Methods and results. It was ascertained that impulse and color doppler examination allows to visualize portal vein and its branches’ structural abnormalities, define subhepatic and intrahepatic types of portal hypertension, find thrombosis and characterize its stages. In cirrhosis patients with portal hypertension, homogenous doppler signal was received from the portal vessels lumen, while signs of intraluminar pathology were seen in the case of thrombosis of portal vein. Conclusion. This means that ultrasound examination of portal vein and its branches with impulse and color doppler is informative, non invasive method, which helps to define stages of portal hypertension. Doppler ultrasonography doesn’t have negative effect of ionizing radiation and can be used for the repeated research in the dynamics of disease.

  11. Superimposed noninterfering probes to extend the capabilities of phase Doppler anemometry.

    Science.gov (United States)

    Onofri, Fabrice; Lenoble, Anne; Radev, Stefan

    2002-06-20

    We propose using multiple superimposed noninterfering probes (SNIPs) of the same wavelength but different beam angles to extend the capabilities of phase Doppler anemometry. When a particle is moving in a SNIP the Doppler signals that are produced exhibit multiple Doppler frequencies and phase shifts. The resolution of the measurements of particle size (i.e., by fringe spacing and Doppler frequency) increases with beam angle. Then, with the solution proposed, even with only two detectors several measurements of size can be obtained for the same particle with increasing resolution if we consider higher frequencies in the signal. Several optical solutions to produce SNIPs as well as a signal-processing algorithm to treat the multiple-frequency Doppler signals are proposed. Experimental validations of the sizing of spherical and cylindrical particles demonstrate the applicability of this technique for particle measurement. We believe that this new technique can be of great interest when high resolution of size, velocity, and even refractive index is required.

  12. Technical Note: A new phantom design for routine testing of Doppler ultrasound.

    Science.gov (United States)

    Grice, J V; Pickens, D R; Price, R R

    2016-07-01

    The objective of this project is to demonstrate the principle and operation for a simple, inexpensive, and highly portable Doppler ultrasound quality assurance (QA) phantom intended for routine QA testing. A prototype phantom has been designed, fabricated, and evaluated. The phantom described here is powered by gravity alone, requires no external equipment for operation, and produces a stable fluid velocity useful for quality assurance. Many commercially available Doppler ultrasound testing systems can suffer from issues such as a lengthy setup, prohibitive cost, nonportable size, or difficulty in use. This new phantom design aims to address some of these problems and create a phantom appropriate for assessing Doppler ultrasound stability. The phantom was fabricated using a 3D printer. The basic design of the phantom is to provide gravity-powered flow of a Doppler fluid between two reservoirs. The printed components were connected with latex tubing and then seated in a tissue mimicking gel. Spectral Doppler waveforms were sampled to evaluate variations in the data, and the phantom was evaluated using high frame rate video to find an alternate measure of mean fluid velocity flowing in the phantom. The current system design maintains stable flow from one reservoir to the other for approximately 7 s. Color Doppler imaging of the phantom was found to be qualitatively consistent with laminar flow. Using pulsed spectral Doppler, the average fluid velocity from a sample volume approximately centered in the synthetic vessel was measured to be 56 cm/s with a standard deviation of 3.2 cm/s across 118 measurements. An independent measure of the average fluid velocity was measured to be 51.9 cm/s with a standard deviation of 0.7 cm/s over 4 measurements. The developed phantom provides stable fluid flow useful for frequent clinical Doppler ultrasound testing and attempts to address several obstacles facing Doppler phantom testing. Such an ultrasound phantom can make routine

  13. Application of coincidence Doppler-broadening spectroscopy to different carbon phases

    International Nuclear Information System (INIS)

    Ito, Y.; Djourelov, N.; Suzuki, T.; Kondo, K.; Ito, Y.; Shantarovich, V.; Onoe, J.

    2004-01-01

    Coincidence Doppler-broadening spectroscopy was applied to C60 and C70 fullerenes and other carbon phases, such as nanotubes and graphites. Remarkable differences were observed in the Doppler-broadening of the positron annihilation γ-rays in these materials, which reflect the different densities distribution of the momentum for electrons annihilated with positrons. This would be caused by the different composition of the π and σ electrons in annihilation with positrons. This result shows the sensitivity of the coincidence Doppler-broadening method to determine the density distribution of electrons sampled by positrons. (orig.)

  14. The Next Generation Airborne Polarimetric Doppler Radar

    Science.gov (United States)

    Vivekanandan, J.; Lee, Wen-Chau; Loew, Eric; Salazar, Jorge; Chandrasekar, V.

    2013-04-01

    NCAR's Electra Doppler radar (ELDORA) with a dual-beam slotted waveguide array using dual-transmitter, dual-beam, rapid scan and step-chirped waveform significantly improved the spatial scale to 300m (Hildebrand et al. 1996). However, ELDORA X-band radar's penetration into precipitation is limited by attenuation and is not designed to collect polarimetric measurements to remotely estimate microphysics. ELDORA has been placed on dormancy because its airborne platform (P3 587) was retired in January 2013. The US research community has strongly voiced the need to continue measurement capability similar to the ELDORA. A critical weather research area is quantitative precipitation estimation/forecasting (QPE/QPF). In recent years, hurricane intensity change involving eye-eyewall interactions has drawn research attention (Montgomery et al., 2006; Bell and Montgomery, 2006). In the case of convective precipitation, two issues, namely, (1) when and where convection will be initiated, and (2) determining the organization and structure of ensuing convection, are key for QPF. Therefore collocated measurements of 3-D winds and precipitation microphysics are required for achieving significant skills in QPF and QPE. Multiple radars in dual-Doppler configuration with polarization capability estimate dynamical and microphysical characteristics of clouds and precipitation are mostly available over land. However, storms over complex terrain, the ocean and in forest regions are not observable by ground-based radars (Bluestein and Wakimoto, 2003). NCAR/EOL is investigating potential configurations for the next generation airborne radar that is capable of retrieving dynamic and microphysical characteristics of clouds and precipitation. ELDORA's slotted waveguide array radar is not compatible for dual-polarization measurements. Therefore, the new design has to address both dual-polarization capability and platform requirements to replace the ELDORA system. NCAR maintains a C-130

  15. Assessment of ureterovesical jet dynamics in obstructed ureter by urinary stone with color Doppler and duplex Doppler examinations.

    Science.gov (United States)

    Jandaghi, Ali Babaei; Falahatkar, Siavash; Alizadeh, Ahmad; Kanafi, Alireza Rajabzadeh; Pourghorban, Ramin; Shekarchi, Babak; Zirak, Amin Keshavarz; Esmaeili, Samaneh

    2013-04-01

    This study was designed to evaluate ureterovesical jet dynamics in obstructed ureter and to compare it with those of contralateral unobstructed side. Forty-six patients with diagnosis of ureteral stone, based on imaging findings in computed tomography were enrolled in this study. The gray-scale ultrasound exam from both kidneys and urinary bladder was performed. Then, ureterovesical jet characteristics including ureteral jet frequency, duration and peak velocity were assessed by color Doppler and duplex Doppler studies in both obstructed and unobstructed ureters by a radiologist, 15-30 min after oral hydration with 750-1,000 mL of water. When compared with contralateral normal side, the ureterovesical jet in obstructed ureter showed less frequency (0.59 vs. 3.04 jets/min; P < 0.05), shorter duration (1.24 vs. 5.26 s; P < 0.05) and lower peak velocity (5.41 vs. 32.09 cm/s; P < 0.05). The cut-off points of 1.5 jets/min, 2.5 s and 19.5 cm/s for difference of ureteral jet frequency, duration and peak velocity between obstructed and contralateral normal ureters yielded sensitivities of 97.8, 95.6 and 100 % and specificities of 87, 87.9 and 97.8 %, respectively for diagnosis of ureteral obstruction. Given the safety of Doppler study and significant differences in flow dynamics of obstructed versus unobstructed ureters, our findings demonstrated the utility of Doppler ultrasound examination as a useful adjunct to gray-scale ultrasound by improving the accuracy of ultrasound exam in diagnosis of ureteral obstruction.

  16. Comparative analysis of pulsed doppler ultrasonography of portal vein vs indirect photography

    International Nuclear Information System (INIS)

    Chang, Jae Chun; Kwon, Huck Po; Hwang, Mi Soo; Kim, Sun Youn; Park, Bok Hwan; Lee, Hyun Ju; Kim, Hong Jin

    1990-01-01

    There are some limitation of interpretation in indirect photography via superior mesenteric artery. In order to supplement and predict indirect photography, we compared indirect photographic findings with pulsed doppler flowmetry in 38 hepatobiliary patients, and the results were as follow: 1. In case of normal main portal vein(MPV) filling, Pulsed Doppler always showed antegrade, continuous parabolic wave form and cases of abnormal MPV filling, showed unusual wave form and flow direction. 2. In normal filling case of proximal right portal vein, Pulsed Doppler almost showed normal continuous parabolic wave form but in normal filling cases of proximal left portal vein, occasionally showed undulating wave form. 3. In each side proximal portal vein abnormal filling case, we could observe abnormal doppler wave form and could obtain additional information using doppler wave form. 4. Mean portal flow velocity was significantly increased in higher photography grade(p=0.01) and congestion index was significantly decreased in higher photography grade(p=0.01). 5. We concluded that doppler ultrasonography could supplement incomplete indirect photography

  17. Color Doppler Ultrasonographic Findings of Vascular Leiomyoma: Pathologic Correlation

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Ji Young; Koh, Sung Hye; Min, Soo Kee; Choi, A Lam; Jang, Kyung Mi; Lee, Yul; Lee, Kwan Seop; Lee, Hyun; Sohn, Jeong Hee [Hallym University Sacred Heart Hospital, Anyang (Korea, Republic of); Kim, Sam Soo [Kangwon National University College of Medicine, Chuncheon (Korea, Republic of)

    2009-12-15

    To evaluate the distribution of color flow signals on color Doppler ultrasonography of vascular leiomyomas and to correlate them with pathologic findings. We retrospectively analyzed color Doppler ultrasonographic images and pathologic slides of six vascular leiomyomas. We classified the patterns of distribution of color flow signals into localized compact cluster types and non-cluster types, and the pathologic findings into three subtypes: solid, venous and cavernous. All cases showed well-defined homogenous hypoechoic subcutaneous masses on gray-scale ultrasonography. Three cases showed localized compact cluster types on color Doppler ultrasonography, one in each subtype (solid, venous and cavernous). For the three non-cluster types, again there was on in each subtype. In addition, on pathologic analysis the zone of the localized compact cluster of color flow signals coincided with a cluster of larger, vascular caliber masses. Localized compact clusters of color flow signals on color Doppler ultrasonography were seen in 50% of our cases and correlated with a cluster of larger vascular caliber in the mass. But the pattern of distribution of color flows didn't show a correlation with pathologic type

  18. Color Doppler Ultrasonographic Findings of Vascular Leiomyoma: Pathologic Correlation

    International Nuclear Information System (INIS)

    Ko, Ji Young; Koh, Sung Hye; Min, Soo Kee; Choi, A Lam; Jang, Kyung Mi; Lee, Yul; Lee, Kwan Seop; Lee, Hyun; Sohn, Jeong Hee; Kim, Sam Soo

    2009-01-01

    To evaluate the distribution of color flow signals on color Doppler ultrasonography of vascular leiomyomas and to correlate them with pathologic findings. We retrospectively analyzed color Doppler ultrasonographic images and pathologic slides of six vascular leiomyomas. We classified the patterns of distribution of color flow signals into localized compact cluster types and non-cluster types, and the pathologic findings into three subtypes: solid, venous and cavernous. All cases showed well-defined homogenous hypoechoic subcutaneous masses on gray-scale ultrasonography. Three cases showed localized compact cluster types on color Doppler ultrasonography, one in each subtype (solid, venous and cavernous). For the three non-cluster types, again there was on in each subtype. In addition, on pathologic analysis the zone of the localized compact cluster of color flow signals coincided with a cluster of larger, vascular caliber masses. Localized compact clusters of color flow signals on color Doppler ultrasonography were seen in 50% of our cases and correlated with a cluster of larger vascular caliber in the mass. But the pattern of distribution of color flows didn't show a correlation with pathologic type

  19. Moving Target Detection With Compact Laser Doppler Radar

    Science.gov (United States)

    Sepp, G.; Breining, A.; Eisfeld, W.; Knopp, R.; Lill, E.; Wagner, D.

    1989-12-01

    This paper describes an experimental integrated optronic system for detection and tracking of moving objects. The system is based on a CO2 waveguide laser Doppler ra-dar with homodyne receiver and galvanometer mirror beam scanner. A "hot spot" seeker consisting of a thermal imager with image processor transmits the coordinates of IR-emitting, i.e. potentially powered, objects to the laser radar scanner. The scanner addresses these "hot" locations operating in a large field-of-view (FOV) random ac-cess mode. Hot spots exhibiting a Doppler shifted laser signal are indicated in the thermal image by velocity-to-colour encoded markers. After switching to a small FOV scanning mode, the laser Doppler radar is used to track fast moving objects. Labora-tory and field experiments with moving objects including rotating discs, automobiles and missiles are described.

  20. Three-dimensional laser cooling at the Doppler limit

    Science.gov (United States)

    Chang, R.; Hoendervanger, A. L.; Bouton, Q.; Fang, Y.; Klafka, T.; Audo, K.; Aspect, A.; Westbrook, C. I.; Clément, D.

    2014-12-01

    Many predictions of Doppler-cooling theory of two-level atoms have never been verified in a three-dimensional geometry, including the celebrated minimum achievable temperature ℏ Γ /2 kB , where Γ is the transition linewidth. Here we show that, despite their degenerate level structure, we can use helium-4 atoms to achieve a situation in which these predictions can be verified. We make measurements of atomic temperatures, magneto-optical trap sizes, and the sensitivity of optical molasses to a power imbalance in the laser beams, finding excellent agreement with Doppler theory. We show that the special properties of helium, particularly its small mass and narrow transition linewidth, prevent effective sub-Doppler cooling with red-detuned optical molasses. This discussion can be generalized to identify when a given species is likely to be subject to the same limitation.

  1. Papel do ecocardiograma na avaliação ventricular do coração transplantado versus rejeição cardíaca Role of echocardiography in the ventricular assessment of the transplanted heart versus heart rejection

    Directory of Open Access Journals (Sweden)

    Gabriel Antonio Stanisci Miguel

    2012-11-01

    Full Text Available FUNDAMENTO: O Transplante Cardíaco (TC é uma alternativa para os indivíduos com doença cardíaca terminal. Na evolução pós-transplante, a ocorrência de episódios de Rejeição Cardíaca (RC é evento frequente que aumenta a morbimortalidade, sendo necessário o emprego de exame não invasivo com boa acurácia para seu diagnóstico, pois a Biópsia Endomiocárdica (BEM não é um procedimento isento de complicações. OBJETIVO: Comparar parâmetros obtidos com o princípio Doppler, entre os pacientes transplantados com RC (TX1 e os pacientes transplantados sem rejeição (TX0; utilizando como referência o Grupo Controle (GC e observando o comportamento da função sistodiastólica ventricular esquerda expressa por meio do Índice de Performance Miocárdica (IPM. MÉTODOS: Foram realizados ecocardiogramas transtorácicos no período de janeiro de 2006 a janeiro de 2008, para a avaliação prospectiva de 47 pacientes, subdivididos em GC (36,2%, TX0 (38,3% e TX1 (25,5%, comparando-se o IPM entre eles. Para a análise dos dados foram realizados os testes exato de Fisher e o não paramétrico de Kruskal-Wallis, ambos com nível de significância de 5%. RESULTADOS: Os grupos não diferiram em relação a idade, peso, altura e superfície corpórea. Quando comparado ao GC, TX0 e TX1 apresentaram alteração da função sistodiastólica ventricular esquerda, expressa como aumento do IPM, que foi mais intenso no TX1 [0,38 (0,29 - 0,44 X 0,47 (0,43 - 0,56 X 0,58 (0,52 - 0,74 p BACKGROUND: Heart transplantation is an alternative for individuals with end-stage heart disease. However, episodes of heart rejection (HR are frequent and increase morbidity and mortality, requiring the use of an accurate non-invasive exam for their diagnosis, since endomyocardial biopsy (EMB is not a complication-free procedure. OBJECTIVE: To compare the parameters obtained by use of Doppler echocardiography in a group of transplanted patients with HR (TX1 and another

  2. Color doppler ultrasound diagonosis in cesarean scar pregnancy

    International Nuclear Information System (INIS)

    Chen Shanshan; Xia Fei; Shen Zongji; Xu Jianyin; Gu Xinxian

    2010-01-01

    Objective: To study the sonographic characteristics of cesarean scar pregnancy(CSP), and the value of color Doppler in the diagnosis of CSP. Methods: Twelve cases of CSP were all confirmed by transabdominal and transvaginal ultrasound. Results: The ultrasonogram of CSP could be divided into gestational sac type and mixed mass type. Conclusion: Color Doppler can give guidance to the early diagnosis, treatment and following-up of CSP because of the sonographic specifity of CSP. (authors)

  3. Laser doppler perfusion imaging

    International Nuclear Information System (INIS)

    Waardell, K.

    1992-01-01

    Recording of tissue perfusion is important in assessing the influence of peripheral vascular diseases on the microcirculation. This thesis reports on a laser doppler perfusion imager based on dynamic light scattering in tissue. When a low power He-Ne laser beam sequentally scans the tissue, moving blood cells generate doppler components in the back-scattered light. A fraction of this light is detected by a photodetector and converted into an electrical signal. In the processor, a signal proportional to the tissue perfusion at each measurement site is calculated and stored. When the scanning procedure is completed, a color-coded perfusion image is presented on a monitor. To convert important aspects of the perfusion image into more quantitative parameters, data analysis functions are implemented in the software. A theory describing the dependence of the distance between individual measurement points and detector on the system amplification factor is proposed and correction algorithms are presented. The performance of the laser doppler perfusion imager was evaluated using a flow simulator. A linear relationship between processor output signal and flow through the simulator was demonstrated for blood cell concentrations below 0.2%. The median sampling depth of the laser beam was simulated by a Monte Carlo technique and estimated to 235 μm. The perfusion imager has been used in the clinic to study perfusion changes in port wine stains treated with argon laser and to investigate the intensity and extension of the cutaneous axon reflex response after electrical nerve stimulation. The fact that perfusion can be visualized without touching the tissue implies elimination of sterilization problems, thus simplifying clinical investigations of perfusion in association with diagnosis and treatment of peripheral vascular diseases. 22 refs

  4. [The value of Doppler sonography in the detection of fetal hypoxia].

    Science.gov (United States)

    Aranyosi, János; Zatik, János; Juhász, A Gábor; Fülesdi, Béla; Major, Tamás

    2002-10-27

    Doppler ultrasound has become a part of routine antenatal fetal surveillance during the past two decades. It provides insight into the utero-placental and fetal arterial, venous circulation non-invasively. Doppler examination has a key role in the detection of hypoxic risk since abnormal blood flow patterns can be demonstrated before the clinical manifestation of fetal disorder. Doppler velocimetry facilitates judgment in the diagnosis, monitoring fetal well-being during pregnancy and labor, scheduling antenatal tests and timing delivery. Authors review the effects of chronic and acute hypoxia on fetal hemodynamics. On the basis of the present knowledge and experience a brief summary is given about the role of Doppler velocimetry in the early detection of hypoxic fetal jeopardy during pregnancy and labor.

  5. Doppler Centroid Estimation for Airborne SAR Supported by POS and DEM

    Directory of Open Access Journals (Sweden)

    CHENG Chunquan

    2015-05-01

    Full Text Available It is difficult to estimate the Doppler frequency and modulating rate for airborne SAR by using traditional vector method due to instable flight and complex terrain. In this paper, it is qualitatively analyzed that the impacts of POS, DEM and their errors on airborne SAR Doppler parameters. Then an innovative vector method is presented based on the range-coplanarity equation to estimate the Doppler centroid taking the POS and DEM as auxiliary data. The effectiveness of the proposed method is validated and analyzed via the simulation experiments. The theoretical analysis and experimental results show that the method can be used to estimate the Doppler centroid with high accuracy even in the cases of high relief, instable flight, and large squint SAR.

  6. Doppler velocity measurements from large and small arteries of mice

    Science.gov (United States)

    Reddy, Anilkumar K.; Madala, Sridhar; Entman, Mark L.; Michael, Lloyd H.; Taffet, George E.

    2011-01-01

    With the growth of genetic engineering, mice have become increasingly common as models of human diseases, and this has stimulated the development of techniques to assess the murine cardiovascular system. Our group has developed nonimaging and dedicated Doppler techniques for measuring blood velocity in the large and small peripheral arteries of anesthetized mice. We translated technology originally designed for human vessels for use in smaller mouse vessels at higher heart rates by using higher ultrasonic frequencies, smaller transducers, and higher-speed signal processing. With these methods one can measure cardiac filling and ejection velocities, velocity pulse arrival times for determining pulse wave velocity, peripheral blood velocity and vessel wall motion waveforms, jet velocities for the calculation of the pressure drop across stenoses, and left main coronary velocity for the estimation of coronary flow reserve. These noninvasive methods are convenient and easy to apply, but care must be taken in interpreting measurements due to Doppler sample volume size and angle of incidence. Doppler methods have been used to characterize and evaluate numerous cardiovascular phenotypes in mice and have been particularly useful in evaluating the cardiac and vascular remodeling that occur following transverse aortic constriction. Although duplex ultrasonic echo-Doppler instruments are being applied to mice, dedicated Doppler systems are more suitable for some applications. The magnitudes and waveforms of blood velocities from both cardiac and peripheral sites are similar in mice and humans, such that much of what is learned using Doppler technology in mice may be translated back to humans. PMID:21572013

  7. Pulsed-wave transmitral Doppler do not diagnose moderate acute rejection after heart transplantation

    NARCIS (Netherlands)

    Mannaerts, H. F.; Simoons, M. L.; Balk, A. H.; Tijssen, J.; van der Borden, S. G.; Zondervan, P. E.; Mochtar, B.; Weimar, W.; Roelandt, J. R.

    1993-01-01

    The value of pulsed-wave transmitral Doppler for the diagnosis of moderate acute rejection was examined in a total of 347 Doppler recordings obtained in 32 consecutive cardiac allograft recipients. Serial Doppler examinations (median, 11 per patient; range, 1 to 23) were performed simultaneously

  8. PULSED-WAVE TRANSMITRAL DOPPLER DO NOT DIAGNOSE MODERATE ACUTE REJECTION AFTER HEART-TRANSPLANTATION

    NARCIS (Netherlands)

    MANNAERTS, HF; SIMOONS, ML; BALK, AH; TIJSSEN, J; VANDERBORDEN, SG; ZONDERVAN, PE; MOCHTAR, B; WEIMAR, W; ROELANDT, [No Value

    1993-01-01

    The value of pulsed-wave transmitral Doppler for the diagnosis of moderate acute rejection was examined in a total of 347 Doppler recordings obtained in 32 consecutive cardiac allograft recipients. Serial Doppler examinations (median, 11 per patient; range, 1 to 23) were performed simultaneously

  9. Compressive sensing for high resolution profiles with enhanced Doppler performance

    NARCIS (Netherlands)

    Anitori, L.; Hoogeboom, P.; Chevalier, F. Le; Otten, M.P.G.

    2012-01-01

    In this paper we demonstrate how Compressive Sensing (CS) can be used in pulse-Doppler radars to improve the Doppler performance while preserving range resolution. We investigate here two types of stepped frequency waveforms, the coherent frequency bursts and successive frequency ramps, which can be

  10. Study on Zero-Doppler Centroid Control for GEO SAR Ground Observation

    Directory of Open Access Journals (Sweden)

    Yicheng Jiang

    2014-01-01

    Full Text Available In geosynchronous Earth orbit SAR (GEO SAR, Doppler centroid compensation is a key step for imaging process, which could be performed by the attitude steering of a satellite platform. However, this zero-Doppler centroid control method does not work well when the look angle of radar is out of an expected range. This paper primarily analyzes the Doppler properties of GEO SAR in the Earth rectangular coordinate. Then, according to the actual conditions of the GEO SAR ground observation, the effective range is presented by the minimum and maximum possible look angles which are directly related to the orbital parameters. Based on the vector analysis, a new approach for zero-Doppler centroid control in GEO SAR, performing the attitude steering by a combination of pitch and roll rotation, is put forward. This approach, considering the Earth’s rotation and elliptical orbit effects, can accurately reduce the residual Doppler centroid. All the simulation results verify the correctness of the range of look angle and the proposed steering method.

  11. Precise Doppler shift compensation in the hipposiderid bat, Hipposideros armiger.

    Science.gov (United States)

    Schoeppler, Diana; Schnitzler, Hans-Ulrich; Denzinger, Annette

    2018-03-15

    Bats of the Rhinolophidae and Hipposideridae families, and Pteronotus parnellii, compensate for Doppler shifts generated by their own flight movement. They adjust their call frequency such that the frequency of echoes coming from ahead fall in a specialized frequency range of the hearing system, the auditory fovea, to evaluate amplitude and frequency modulations in echoes from fluttering prey. Some studies in hipposiderids have suggested a less sophisticated or incomplete Doppler shift compensation. To investigate the precision of Doppler shift compensation in Hipposideros armiger, we recorded the echolocation and flight behaviour of bats flying to a grid, reconstructed the flight path, measured the flight speed, calculated the echo frequency, and compared it with the resting frequency prior to each flight. Within each flight, the average echo frequency was kept constant with a standard deviation of 110 Hz, independent of the flight speed. The resting and reference frequency were coupled with an offset of 80 Hz; however, they varied slightly from flight to flight. The precision of Doppler shift compensation and the offset were similar to that seen in Rhinolophidae and P. parnellii. The described frequency variations may explain why it has been assumed that Doppler shift compensation in hipposiderids is incomplete.

  12. Renal Power Doppler Ultrasonographic Evaluation of Children With Acute Pyelonephritis

    Directory of Open Access Journals (Sweden)

    Ali Pahlusi

    2011-10-01

    Full Text Available Urinary tract infections are common in children. The available gold standard method for diagnosis, Tc-99m dimercaptosuccinic acid scan is expensive and exposes patients to considerable amount of radiation. This study was performed to compare and assess the efficacy of Power Doppler Ultrasound versus Tc-99m DMSA scan for diagnosis of acute pyelonephritis. A quasi experimental study was conducted on 34 children with mean age of 2.82.7 years who were hospitalized with their first episode of febrile urinary tract infection. All children were evaluated in the first 3 days of admission by Doppler Ultrasound and Tc-99m DMSA scan. Patients with congenital structural anomalies were excluded. Each kidney was divided into three zones. The comparison between efficacy of Doppler Ultrasound and DMSA scan was carried out based on number of patients and on classified renal units. Based on the number of patients enrolled; the sensitivity, specificity, positive and negative predictive values and accuracy of Doppler Ultrasound were 89%, 53%, 70%, 80% and 74%, respectively but based on the renal units, it was 66%, 81%, 46%, 91% and 79% , respectively. Although Doppler Ultrasound has the potential for identifying acute pyelonephritis in children, but it is still soon to replace DMSA scan.

  13. Endosonographic and color doppler flow imaging alterations observed within irradiated rectal cancer

    International Nuclear Information System (INIS)

    Alexander, Archie A.; Palazzo, Juan P.; Ahmad, Neelofur R.; Liu, J.-B.; Forsberg, Flemming; Marks, John

    1996-01-01

    Purpose: To correlate the endosonographic and color Doppler flow imaging alterations observed in irradiated rectal cancers with the pathologic features of radiation response, and to evaluate the potential impact of altered blood flow on the integrity of the surgical anastamosis. Methods and Materials: Endosonography with color and pulsed wave Doppler was performed on 20 rectal cancer masses before and after high dose preoperative radiation (XRT). Pre- and post-XRT observations included comparing alterations in tumor size, sonographic echotexture, color Doppler flow, and pulsatility indices. Comparisons were made with pathologic findings in the irradiated specimens and with the incidence of anastomotic failure. Results: Compared to pre-XRT observations, irradiated rectal cancers decreased in size and became either mixed in echogenicity with less apparent color Doppler flow (16 of 20) or unchanged in color Doppler flow and echotexture (4 of 20). Those with less flow (16 of 20) were imaged later (mean = 90.2 ± 12.1 days) than those without change in color Doppler flow (mean = 21.7 ± 2.7 days). Pathologically, the group of four without change in color Doppler signal had features of acute inflammation which were not observed in 16 of 20 imaged later. Based on pulsatility index measurements, both high and low resistance vessels were detected and confirmed by immunohistochemical staining, and features of postradiation obliterative vasculitis were observed. Only one primary anastomosis in 14 patients with decreased flow failed. Conclusions: The sonographic and color Doppler flow imaging alterations observed within irradiated rectal cancer correlated with changes of postradiation obliterative vasculitis. The apparent diminished local blood flow within high and low resistance vessels post-XRT did not result in an increased incidence of anastomotic failures

  14. Tissue Doppler echocardiography – A case of right tool, wrong use

    Directory of Open Access Journals (Sweden)

    Thomas George

    2004-08-01

    Full Text Available Abstract Background The developments in echocardiography or ultrasound cardiography (UCG have improved our clinical capabilities. However, advanced hardware and software capabilities have resulted in UCG facilities of dubious clinical benefits. Is tissue Doppler echocardiography (TDE is one such example? Presentation of the hypothesis TDE has been touted as advancement in the field of echocardiography. The striking play of colors, impressive waveforms and the seemingly accurate velocity values could be deceptive. TDE is a clear case of inappropriate use of technology. Testing the hypothesis To understand this, a comparison between flow Doppler and tissue Doppler is made. To make clinically meaningful velocity measurements with Doppler, we need prior knowledge of the line of motion. This is possible in blood flow but impossible in the complex myocardial motion. The qualitative comparison makes it evident that Doppler is best suited for flow studies. Implications of the hypothesis As of now TDE is going backwards using an indirect method when direct methods are better. The work on TDE at present is only debatable 'research and publication' material and do not translate into tangible clinical benefits. There are several advances like curved M-mode, strain rate imaging and tissue tracking in TDE. However these have been disappointing. This is due to the basic flaw in the application of the principles of Doppler. Doppler is best suited for flow studies and applying it to tissue motion is illogical. All data obtained by TDE is scientifically incorrect. This makes all the published papers on the subject flawed. Making diagnostic decisions based on this faulty application of technology would be unacceptable to the scientific cardiologist.

  15. Doppler-guided hemorrhoidal artery ligation in the management of symptomatic hemorrhoids Ligadura de las arterias hemorroidales guiada por Doppler en el tratamiento de las hemorroides sintomáticas

    Directory of Open Access Journals (Sweden)

    J. M. Ramírez

    2005-02-01

    Full Text Available Objective: the aim of this study is to clinically test the efficacy of a new approach for patients having symptomatic grade III and IV hemorrhoids. Material and method: 32 patients (17 females complaining of grade III or IV hemorrhoids were included in the study. A specially designed proctoscope coupled with a Doppler transducer on its tip was used to identify the hemorrhoidal arteries, which were afterwards suture ligated. Operating time as well as per- and post-operative complications were anlyzed. Follow-up was planned following discharge after 1 week, 1 month, 6 months and 1 year. Results: mean operation time was 27 (range 18-43 minutes, and 5 (range 4-7 arteries were located on average. No patient had severe or moderate postoperative pain, with anal discomfort being the main complaint. Rectal bleeding and tenesmus were the commonest post-operative complications. After one year of follow-up, 19 patients were free of symptoms and 6 of them had significant symptom relief. According to grade, the technique failed in just 3 grade III patients, but in as many as 4 grade IV hemorrhoid cases. Conclusions: doppler-guided hemorrhoid artery ligation is an easy-to-perform technique that is well accepted by patients and has good results for grade III hemorrhoids.Objetivo: el objetivo de este trabajo es valorar en la clínica la eficacia de una nueva técnica quirúrgica para el tratamiento de las hemorroides de grado III y IV. Material y método: se incluyen en el estudio 32 pacientes (17 mujeres, 27 presentaban hemorroides de grado III y 5 de grado IV. Para la técnica se utilizó un prostoscopio transparente que incorpora un transductor Doppler en su extremo para localizar las arterias hemorroidales que se ligan mediante puntos que engloban la mucosa y submucosa. Se analizó el tiempo de intervención y las complicaciones intra y postoperatorias, así como las recidivas. Los pacientes fueron controlados al alta, a la semana, mes, 6 meses y al año de

  16. Phylloedes tumor of breast: findings at mammography, sonography and color Doppler imaging

    International Nuclear Information System (INIS)

    Park, Kun Choon; Ahn, Sei Hyun; Kim, Young Hwan; Choi, Hye Yong; Baek, Seung Yon; Yoon, Jeong Hyun

    1994-01-01

    The phylloides tumor of the breast is rare. the purposes of this study were to find the characteristic findings at mammography, sonography, and color Doppler imaging and to evaluate the usefulness of color Doppler study as an additional modality in the diagnosis of phylloides tumor and differentiation between benign and malignant varieties. Eight cases, who were pathologically proven as pylloides tumors, were retrospectively studied. The findings at histologic examination suggested benign in five, malignantin two, and borderline in one. We analyzed the mammograms of all eight patients and sonogram and color Doppler images of four patients. Phylloides tumors were seen as dense masses with lobulated margins in mammograms. On sonography, they showed relatively well-defined masses with in homogenous internal echo pattern and central echogenic areas. They were characterized by the presence of arterial and venous flows in the center and periphery of the lesion on color Doppler imaging and spectral analysis. We conclude that mammographic, sonographic and even color Doppler findings are not predictive of benign or malignant nature of the phylloides tumor. However, mammography and sonography with color Doppler interrogation are helpful in the diagnosis of phylloides tumor

  17. TORSION TESTIS : ROLE OF COLOR DOPPLER : A STUDY OF 50 CASES

    Directory of Open Access Journals (Sweden)

    Anand

    2015-09-01

    Full Text Available BACKGROUND: T orsion testis is one of the catast r ophic conditions in children and young a d u lts. Traditionally the diagnosis was made clinical presentation and suspicion. Critical decision making is essential to save the testis . OBJECTIVE: To study the usefu lness and efficacy of Doppler ultrasound in correctly diagnosing acute scrotal conditions in children and young adults to save the testis and to avoid negative explorations. METHODS: Over a period of two years 50 patients with acute scrotum were admitted i n general surgery department who underwent Doppler ultrasound scrotum and its efficacy in correctly diagnosing the pathology was analysed. RESULTS: 50 patients with age group <25 years were included in study. Scrotal pain was the most frequent presenting s ymptom of acute scrotum (98% followed by Swelling of the hemiscrolum on the involved side present in 86% of the patients. Doppler ultrasound showed torsion of testis in 18 patients. On Scrotal exploration, torsion of spermatic cord was confirmed in 16 pat ients, one patient had torsion of appendix of testis and the other had Epididymo - orchitis. Thus the sensitivity and specificity of Doppler ultrasonography for testicular torsion was 86.9% and 92.6% respectively. 2 patients with equivocal Doppler findings, but strong clinical suspicion of testicular torsion were explored, and testis was found to be torsed in both two patients. Doppler ultrasonography showed Epididymo - orchitis in 22 patients, torsion of testicular appendage in 2 patients, Idiopathic scrotal edema in one, and in 5 pts no significant pathology found. All twenty patients of epididymo - orchitis, two patients of torsion of testicular appendage, and one patient of idiopathic scrotal edema were managed conservatively. At three weeks follow up, all th e patients were free of symptoms. The sensitivity and specificity of Doppler ultrasonography for epididymo - orchitis was 95% and 100% respectively. CONCLUSIONS: color

  18. High-frequency Doppler ultrasound transducer for the peripheral circulatory system

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Youngmin; Yang, Jeongwon; Kang, Uk; Kim, Guanghoon [Korea Electrotechnology Research Institute, Ansan (Korea, Republic of)

    2011-12-15

    A Doppler ultrasound transducer was designed and implemented to measure the blood flow velocity in tiny vessels near the skin of hands or feet. The geometric parameters of the transducer for defining the observation volume were derived and implemented with an acoustic window made of polystyrene. The observation volume designed in this study was located 6.5 mm from the transducer, which was comparable to the value predicted geometrically. The two-way insertion loss of the transducer was -11.3 dB on ultrasound frequency of 20 MHz, and the 3-dB bandwidth was approximately 2 MHz. In addition, the Doppler shift in the frequency measured by using a Doppler device composed of the transducer and a Doppler signal processing unit was proportional to the flow velocity generated by a homemade flowing system. Finally, we concluded that the transducer could be applied to measure the blood flow velocity in hands or feet.

  19. High-frequency Doppler ultrasound transducer for the peripheral circulatory system

    International Nuclear Information System (INIS)

    Bae, Youngmin; Yang, Jeongwon; Kang, Uk; Kim, Guanghoon

    2011-01-01

    A Doppler ultrasound transducer was designed and implemented to measure the blood flow velocity in tiny vessels near the skin of hands or feet. The geometric parameters of the transducer for defining the observation volume were derived and implemented with an acoustic window made of polystyrene. The observation volume designed in this study was located 6.5 mm from the transducer, which was comparable to the value predicted geometrically. The two-way insertion loss of the transducer was -11.3 dB on ultrasound frequency of 20 MHz, and the 3-dB bandwidth was approximately 2 MHz. In addition, the Doppler shift in the frequency measured by using a Doppler device composed of the transducer and a Doppler signal processing unit was proportional to the flow velocity generated by a homemade flowing system. Finally, we concluded that the transducer could be applied to measure the blood flow velocity in hands or feet.

  20. Proposed protocols for peripheral and renal Doppler

    International Nuclear Information System (INIS)

    Fonseca Portuguez, Adriana

    2009-01-01

    A literature review was performed in order to prepare a summary of the important concepts of Doppler and applications in peripheral vascular evaluation and renal. The normal characteristics are summarized and explained in each vascular system and diagnostic criteria of the disorders frequently encountered in practice. Requested more studies have been identified and proposed protocols and report sheets have been developed to standardize the methodology of realization of several Doppler studies. The variability between operators has been treated to reduce as much as possible and follow-up studies have provided in patients who need. (author) [es

  1. Doppler broadening of cross sections

    International Nuclear Information System (INIS)

    Buckler, P.A.C.; Pull, I.C.

    1962-12-01

    Expressions for temperature dependent cross-sections in terms of resonance parameters are obtained, involving generalisations of the conventional Doppler functions, ψ and φ. Descriptions of Fortran sub-routines, which calculate broadened cross-sections in accordance with the derived formulae, are included. (author)

  2. A simplified study of trans-mitral Doppler patterns

    Directory of Open Access Journals (Sweden)

    Thomas George

    2008-11-01

    Full Text Available Abstract Background Trans-mitral Doppler produces complex patterns with a great deal of variability. There are several confusing numerical measures and indices to study these patterns. However trans-mitral Doppler produces readymade data visualization by pattern generation which could be interpreted by pattern analysis. By following a systematic approach we could create an order and use this tool to study cardiac function. Presentation of the hypothesis In this new approach we eliminate the variables and apply pattern recognition as the main criterion of study. Proper terminologies are also devised to avoid confusion. In this way we can get some meaningful information. Testing the hypothesis Trans-mitral Doppler should be seen as patterns rather than the amplitude. The hypothesis can be proven by logical deduction, extrapolation and elimination of variables. Trans-mitral flow is also analyzed vis-à-vis the Starling's Law applied to the left atrium. Implications of the hypothesis Trans-mitral Doppler patterns are not just useful for evaluating diastolic function. They are also useful to evaluate systolic function. By following this schema we could get useful diagnostic information and therapeutic options using simple pattern recognition with minimal measurements. This simplified but practical approach will be useful in day to day clinical practice and help in understanding cardiac function better. This will also standardize research and improve communication.

  3. Radar Micro-Doppler Feature Extraction Using the Singular Value Decomposition

    NARCIS (Netherlands)

    Wit, J.J.M. de; Harmanny, R.I.A.; Molchanov, P.

    2014-01-01

    Abstract—The micro-Doppler spectrogram depends on parts of a target moving and rotating in addition to the main body motion (e.g., spinning rotor blades) and is thus characteristic for the type of target. In this study, the micro-Doppler spectrogram is exploited to distinguish between birds and

  4. Acoustic doppler methods for remote measurements of ocean flows - a review

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, A.

    The evolution of acoustic doppler methods for remote measurements of ocean flows has been briefly reviewed in historical perspective. Both Eulerian and profiling methods have been discussed. Although the first acoustic Doppler current meter has been...

  5. Developments in target micro-Doppler signatures analysis: radar imaging, ultrasound and through-the-wall radar

    OpenAIRE

    Clemente, C.; Balleri, A.; Woodbridge, K.; Soraghan, J. J.

    2013-01-01

    Target motions, other than the main bulk translation of the target, induce Doppler modulations around the main Doppler shift that form what is commonly called a target micro-Doppler signature. Radar micro-Doppler signatures are generally both target and action speci c and hence can be used to classify and recognise targets as well as to identify possible threats. In recent years, research into the use of micro-Doppler signatures for target classi cation to address many defence and security ch...

  6. Numerical stud of glare spot phase Doppler anemometry

    OpenAIRE

    Hespel , Camille; Ren , Kuan Fang; Gréhan , Gérard; Onofri , Fabrice

    2008-01-01

    International audience; The phase Doppler anemometry has (PDA) been developed to measure simultaneously the velocity and the size of droplets. When the concentration of particles is high, tightly focused beams must be used, as in the dual burst PDA. The latter permits an access to the refractive index of the particle, but the effect of wave front curvature of the incident beams becomes evident. In this paper, we introduce a glare spot phase Doppler anemometry which uses two large beams. The i...

  7. Transcranial Doppler ultrasound and cerebral angiography - alternative or complementary

    International Nuclear Information System (INIS)

    Bockenheimer, S.; Lorey, N.

    1985-01-01

    Transcranial Doppler ultrasound is a noninvasive method of recording the flow velocity of larger intracranial vessels. The impact on diagnosis of cerebravascular occlusive disease is not yet evaluated. We present 15 patients, age range 39-73 years, who suffered from completed stroke. The findings of transcranial Doppler ultrasound and of cerebral angiography are presented. The value of both methods in treatment strategy is discussed. (orig.) [de

  8. Predictable progressive Doppler deterioration in IUGR: does it really exist?

    LENUS (Irish Health Repository)

    Unterscheider, Julia

    2013-12-01

    An objective of the Prospective Observational Trial to Optimize Pediatric Health in IUGR (PORTO) study was to evaluate multivessel Doppler changes in a large cohort of intrauterine growth restriction (IUGR) fetuses to establish whether a predictable progressive sequence of Doppler deterioration exists and to correlate these Doppler findings with respective perinatal outcomes.

  9. [Doppler echocardiography of tricuspid insufficiency. Methods of quantification].

    Science.gov (United States)

    Loubeyre, C; Tribouilloy, C; Adam, M C; Mirode, A; Trojette, F; Lesbre, J P

    1994-01-01

    Evaluation of tricuspid incompetence has benefitted considerably from the development of Doppler ultrasound. In addition to direct analysis of the valves, which provides information about the mechanism involved, this method is able to provide an accurate evaluation, mainly through use of the Doppler mode. In addition to new criteria being evaluated (mainly the convergence zone of the regurgitant jet), some indices are recognised as good quantitative parameters: extension of the regurgitant jet into the right atrium, anterograde tricuspid flow, laminar nature of the regurgitant flow, analysis of the flow in the supra-hepatic veins, this is only semi-quantitative, since the calculation of the regurgitation fraction from the pulsed Doppler does not seem to be reliable; This accurate semi-quantitative evaluation is made possible by careful and consistent use of all the criteria available. The authors set out to discuss the value of the various evaluation criteria mentioned in the literature and try to define a practical approach.

  10. Contrast-enhanced power Doppler US in the characterization of renal masses

    International Nuclear Information System (INIS)

    Ascenti, G.; Zimbaro, G.; Mazziotti, S.; Visalli, C.; Racchiusa, S.; Vinci, S.; Scribano, E.

    2000-01-01

    Purpose of this work is to report the results of a prospective study investigating the potentials of contrast-enhanced power Doppler in the diagnosis of expansive renal lesions. From 1997 to October 30, 1999, it was studied the case of 59 expansive renal lesions (28 malignant, 31 benign) in 48 patients (mean age 55 years, range 10-79) with power Doppler US before and after the administration of an echo-enhancing agent (Levovist, Schering AG, Berlin Germany). Were found 5 patterns of vascular architecture of the lesions, both before and after contrast agent administration, following the classification by Jinzaki e Coll. Power Doppler US showed vascular structures in 34 patients. The administration of Levovist revealed vessels in 12/25 lesions which had none at baseline studies and in 6 cases vascularity was particularly evident. Color signals were enhanced in all the 34 vascularized lesions, which allowed better definition of vascular patterns. The characterization of vascular patterns with baseline power Doppler US helped improve diagnostic accuracy compared to gray-scale US (58% versus 32%) for hyperechoic lesions, complex cysts and pseudomasses. Independent of contrast agent administration, the integration of gray-scale and power Doppler modes increased diagnostic accuracy even further (76% correct diagnoses). In our series, the US contrast agent did not increase the diagnostic accuracy of power Doppler in the differential diagnosis of hyperechoic renal lesions; conversely, Levovist can be advantageous for the characterization of suspected pseudomasses and complex cysts [it

  11. Micro-Doppler Ambiguity Resolution for Wideband Terahertz Radar Using Intra-Pulse Interference.

    Science.gov (United States)

    Yang, Qi; Qin, Yuliang; Deng, Bin; Wang, Hongqiang; You, Peng

    2017-04-29

    Micro-Doppler, induced by micro-motion of targets, is an important characteristic of target recognition once extracted via parameter estimation methods. However, micro-Doppler is usually too significant to result in ambiguity in the terahertz band because of its relatively high carrier frequency. Thus, a micro-Doppler ambiguity resolution method for wideband terahertz radar using intra-pulse interference is proposed in this paper. The micro-Doppler can be reduced several dozen times its true value to avoid ambiguity through intra-pulse interference processing. The effectiveness of this method is proved by experiments based on a 0.22 THz wideband radar system, and its high estimation precision and excellent noise immunity are verified by Monte Carlo simulation.

  12. A Comprehensive Radial Velocity Error Budget for Next Generation Doppler Spectrometers

    Science.gov (United States)

    Halverson, Samuel; Ryan, Terrien; Mahadevan, Suvrath; Roy, Arpita; Bender, Chad; Stefansson, Guomundur Kari; Monson, Andrew; Levi, Eric; Hearty, Fred; Blake, Cullen; hide

    2016-01-01

    We describe a detailed radial velocity error budget for the NASA-NSF Extreme Precision Doppler Spectrometer instrument concept NEID (NN-explore Exoplanet Investigations with Doppler spectroscopy). Such an instrument performance budget is a necessity for both identifying the variety of noise sources currently limiting Doppler measurements, and estimating the achievable performance of next generation exoplanet hunting Doppler spectrometers. For these instruments, no single source of instrumental error is expected to set the overall measurement floor. Rather, the overall instrumental measurement precision is set by the contribution of many individual error sources. We use a combination of numerical simulations, educated estimates based on published materials, extrapolations of physical models, results from laboratory measurements of spectroscopic subsystems, and informed upper limits for a variety of error sources to identify likely sources of systematic error and construct our global instrument performance error budget. While natively focused on the performance of the NEID instrument, this modular performance budget is immediately adaptable to a number of current and future instruments. Such an approach is an important step in charting a path towards improving Doppler measurement precisions to the levels necessary for discovering Earth-like planets.

  13. Carotid Doppler ultrasound findings in patients with left ventricular assist devices.

    Science.gov (United States)

    Cervini, Patrick; Park, Soon J; Shah, Dipesh K; Penev, Irina E; Lewis, Bradley D

    2010-12-01

    Left ventricular assist devices (LVADs) have been used to treat advanced heart failure refractory to medical management, as bridge therapy to myocardial recovery, as bridge therapy to cardiac transplantation, or as destination therapy for patients with unfavorable transplant candidacy. Neurologic complications are some of the most common and devastating complications in these patients. Preoperative carotid ultrasound is, therefore, a standard evaluation in patients at risk for cerebrovascular disease. Postoperative carotid artery Doppler sonography is performed in those patients with neurologic symptoms. It is likely, therefore, that sonographers, radiologists, and other physicians working in a center where LVADs are implanted will likely encounter a carotid artery Doppler study in this patient group. To our knowledge, the carotid Doppler findings in these patients have never been published. We review the Doppler ultrasound findings in 6 patients after LVAD insertion.

  14. Narrowing of electromagnetically induced transparency resonance in a Doppler-broadened medium

    International Nuclear Information System (INIS)

    Javan, Ali; Kocharovskaya, Olga; Lee Hwang; Scully, Marlan O.

    2002-01-01

    We derive an analytic expression for the linewidth of electromagnetically induced transparency (EIT) resonance in a Doppler-broadened system. It is shown here that for relatively low intensity of the driving field the EIT linewidth is proportional to the square root of intensity and is independent of the Doppler width, similar to the laser-induced line narrowing effect described by Feld and Javan. In the limit of high intensity we recover the usual power-broadening case where the EIT linewidth is proportional to the intensity and inversely proportional to the Doppler width

  15. Theoretical study of electromagnetically induced transparency in a five-level atom and application to Doppler-broadened and Doppler-free Rb atoms

    International Nuclear Information System (INIS)

    Bhattacharyya, Dipankar; Ray, Biswajit; Ghosh, Pradip N

    2007-01-01

    We report theoretical studies of a Λ-type five-level atomic system. The density matrix equations are set up and solved numerically to obtain the probe absorption line shape of Rb D 2 transitions for cold (Doppler-free) and room temperature (Doppler-broadened) atoms. Simulated spectra for Doppler-broadened systems lead to four velocity-selective dips along with an electromagnetic induced transparency (EIT) peak as observed earlier from the co-propagating pump-probe spectroscopy of Rb D 2 transitions. Effects of pump power and spontaneous decay rate from the upper levels on the simulated spectra are also studied. For cold atoms a very pronounced EIT peak is observed when the pump frequency is on resonance with one allowed transition. We find that lower pump power leads to a much sharper EIT signal in this case. A simulated dispersion curve shows a rapid variation of the refractive index that may lead to a sharp reduction of the group velocity of photons

  16. Ultrasonic intrusion sensor using the Doppler effect; Choonpa Doppler hoshiki shinnyu sensor

    Energy Technology Data Exchange (ETDEWEB)

    Kani, H; Iwasaki, N; Goto, M [Nippon Soken, Inc., Tokyo (Japan); Tsuzuki, T; Nakamura, T [Denso Corp., Aichi (Japan)

    1997-10-01

    For vehicle anti-theft alarm systems which cope with vehicle and car component theft, EU initiated vehicle security regulations from Jan 1997. Also, the insurance industry has instituted the insurance certification of vehicle anti-theft alarm systems. We have developed an ultrasonic intrusion sensor using the doppler effect for vehicle anti-theft alarm systems specifically for these EU regulations and insurance certification. 2 refs., 7 figs., 1 tab.

  17. Imaging doppler lidar for wind turbine wake profiling

    Science.gov (United States)

    Bossert, David J.

    2015-11-19

    An imaging Doppler lidar (IDL) enables the measurement of the velocity distribution of a large volume, in parallel, and at high spatial resolution in the wake of a wind turbine. Because the IDL is non-scanning, it can be orders of magnitude faster than conventional coherent lidar approaches. Scattering can be obtained from naturally occurring aerosol particles. Furthermore, the wind velocity can be measured directly from Doppler shifts of the laser light, so the measurement can be accomplished at large standoff and at wide fields-of-view.

  18. Radar micro-Doppler of wind turbines : Simulation and analysis using rotating linear wire structures

    NARCIS (Netherlands)

    Krasnov, O.A.; Yarovoy, A.

    2015-01-01

    A simple electromagnetic model of wind-turbine's main structural elements as the linear wired structures is developed to simulate the temporal patterns of observed radar return Doppler spectra (micro-Doppler). Using the model, the micro-Doppler for different combinations of the turbines rotation

  19. Transthoracic Doppler echocardiography to predict optimal tube pulsing window for coronary artery CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Gang, E-mail: cjr.sungang@vip.163.com [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Li, Min, E-mail: limin22000@yahoo.com.cn [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Jiang, Xiang-sen, E-mail: jiangxiangsen123@126.com [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Li, Li, E-mail: leely1976@yahoo.com.cn [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Peng, Zhao-hui, E-mail: zhaohuipeng_R@163.com [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Mu, Nan-nan, E-mail: munannan22000@sohu.com [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China)

    2012-09-15

    Rationale and objective: To evaluate the feasibility of transthoracic Doppler echocardiography to determine the optimal pulsing windows for CT coronary angiography to narrow the pulsing windows further, especially in higher heart rate. Materials and methods: Doppler was performed on 135 patients before CT scanning. For Doppler, the intervals with minimal motion were evaluated during both systole and diastole integrating electrocardiogram (ECG) intervals. For CT scanning, the retrospective ECG-gating was applied and the optimal reconstruction intervals were determined. The accuracy of Doppler analysis to predict the optimal reconstruction intervals was tested. The predicted length of pulsing windows was compared between Doppler analysis and traditional prospective ECG-gating protocol (heart rate ≦ 65 bpm, 60–76%; 66–79 bpm, 30–77%; ≧80 bpm, 31–47%). Results: According to Doppler analysis, the mean length of intervals with minimal motion in systole was 106.4 ± 39.2 ms and 125.2 ± 92.0 ms in diastole. When the intervals with minimal motion during diastole > 90 ms, the optimal reconstruction intervals were located at diastole; otherwise, at systole (P < 0.001). The optimal reconstruction intervals in 93.8% (132/135) patients could be predicted accurately by Doppler analysis. If the optimal reconstruction intervals predicted by Doppler were applied as the exposure windows, the mean length of pulsing windows should has been 105.2 ± 69.4 ms (range: 26.9–510.3 ms), which was significantly shorter than that of traditional prospective ECG-gating protocol (232.0 ± 120.2 ms, range: 93.2–427.3 ms, P < 0.001). Conclusion: Doppler can help detecting the optimal pulsing windows accurately. Prospective ECG-gating incorporating Doppler analysis may narrow pulsing windows significantly while maintaining image quality.

  20. Transthoracic Doppler echocardiography to predict optimal tube pulsing window for coronary artery CT angiography

    International Nuclear Information System (INIS)

    Sun, Gang; Li, Min; Jiang, Xiang-sen; Li, Li; Peng, Zhao-hui; Mu, Nan-nan

    2012-01-01

    Rationale and objective: To evaluate the feasibility of transthoracic Doppler echocardiography to determine the optimal pulsing windows for CT coronary angiography to narrow the pulsing windows further, especially in higher heart rate. Materials and methods: Doppler was performed on 135 patients before CT scanning. For Doppler, the intervals with minimal motion were evaluated during both systole and diastole integrating electrocardiogram (ECG) intervals. For CT scanning, the retrospective ECG-gating was applied and the optimal reconstruction intervals were determined. The accuracy of Doppler analysis to predict the optimal reconstruction intervals was tested. The predicted length of pulsing windows was compared between Doppler analysis and traditional prospective ECG-gating protocol (heart rate ≦ 65 bpm, 60–76%; 66–79 bpm, 30–77%; ≧80 bpm, 31–47%). Results: According to Doppler analysis, the mean length of intervals with minimal motion in systole was 106.4 ± 39.2 ms and 125.2 ± 92.0 ms in diastole. When the intervals with minimal motion during diastole > 90 ms, the optimal reconstruction intervals were located at diastole; otherwise, at systole (P < 0.001). The optimal reconstruction intervals in 93.8% (132/135) patients could be predicted accurately by Doppler analysis. If the optimal reconstruction intervals predicted by Doppler were applied as the exposure windows, the mean length of pulsing windows should has been 105.2 ± 69.4 ms (range: 26.9–510.3 ms), which was significantly shorter than that of traditional prospective ECG-gating protocol (232.0 ± 120.2 ms, range: 93.2–427.3 ms, P < 0.001). Conclusion: Doppler can help detecting the optimal pulsing windows accurately. Prospective ECG-gating incorporating Doppler analysis may narrow pulsing windows significantly while maintaining image quality

  1. Principles of doppler tomography

    International Nuclear Information System (INIS)

    Juhlin, P.

    1992-08-01

    This paper shows how the radon transform can be used to determine vector fields. A scheme to determine the velocity field of a moving fluid by measurements with a continuous doppler signal is suggested. When the flow is confined to a bounded domain, as is the case in most applications, it can be uniquely decomposed into one gradiental and one rotational part. The former vanishes if the fluid is incompressible and source-free, and the latter can be completely reconstructed by the methods proposed in this paper if the domain is simply connected. Special attention is paid to laminar flow in a long cylindrical vessel with circular cross-section. Under such conditions the flow profile becomes parabolic, which makes the vessel recognizable as a typical 'N-shaped' pattern in an image describing the rotation of the velocity field. The vessel yields the same doppler tomographic pattern, no matter how it is sectioned. The ideas presented should be applicable also when studying the flow in blood vessels, even if the flow profile in these is not quite parabolic. The discrepancies only make the 'N-shape' somewhat distorted

  2. Analysis of Doppler effect measurement in FCA cores using JENDL-3.2 library

    International Nuclear Information System (INIS)

    Okajima, Shigeaki

    1996-01-01

    For the evaluation of the calculation accuracy of the 238 U Doppler effect using JENDL-3.2 library, the previously measured Doppler reactivity worths in the FCA were systematically analyzed. In the analysis the Doppler reactivity worth was calculated by a first order perturbation theory. The calculated results were compared with those using JENDL-3.1 library. The JENDL-3.2 calculation in MOX fuel mock-up cores agrees well with the experimental values within the experimental error. In U-235/Pu fuel cores, the JENDL-3.2 calculation gives 12-15% larger Doppler reactivity worths than the JENDL-3.1 calculation. (author)

  3. Development of Rayleigh Doppler lidar for measuring middle atmosphere winds

    Science.gov (United States)

    Raghunath, K.; Patra, A. K.; Narayana Rao, D.

    Interpretation of most of the middle and upper atmospheric dynamical and chemical data relies on the climatological description of the wind field Rayleigh Doppler lidar is one instrument which monitors wind profiles continuously though continuity is limited to clear meteorological conditions in the middle atmosphere A Doppler wind lidar operating in incoherent mode gives excellent wind and temperature information at these altitudes with necessary spectral sensitivity It observes atmospheric winds by measuring the spectral shift of the scattered light due to the motions of atmospheric molecules with background winds and temperature by spectral broadening The presentation is about the design and development of Incoherent Doppler lidar to obtain wind information in the height regions of 30-65 km The paper analyses and describes various types of techniques that can be adopted viz Edge technique and Fringe Imaging technique The paper brings out the scientific objectives configuration simulations error sources and technical challenges involved in the development of Rayleigh Doppler lidar The presentation also gives a novel technique for calibrating the lidar

  4. Color Doppler US of the penis

    Energy Technology Data Exchange (ETDEWEB)

    Bertolotto, Michele (ed.) [Trieste Univ. Ospedale di Cattinara (Italy). Dept. Radiology

    2008-07-01

    This book provides a comprehensive reference and practical guide on the application of US to penile diseases and conditions. After introductory chapters on technical requirements and penile anatomy, subsequent chapters offer a systematic overview of the diverse applications of color Doppler US. The topics covered include erectile dysfunction, Peyronie's disease, priapism, trauma, tumors, the postoperative penis, inflammation, and fibrosis. Each topic is introduced by a clinical overview with the purpose of clarifying the problems and elucidating what the urologist may expect from color Doppler US. Thereafter, performance of the US study is explained and the pathological anatomy reviewed. High-quality images obtained with high-end US equipment are included. Each chapter also contains a section on the diagnostic information provided by other imaging modalities, and in particular MRI. (orig.)

  5. Determination of intestinal viability by Doppler ultrasonography in venous infarction.

    Science.gov (United States)

    Cooperman, M; Martin, E W; Carey, L C

    1980-01-01

    The accuracy of Doppler ultrasound in predicting the viability of ischemic intestine secondary to venous obstruction was assessed. Twenty loops of ischemic intestine were created in dogs by temporarily obstructing venous return from the bowel. Doppler arterial flow signals within the intestine quickly disappeared following venous occlusion. In ten segments, arterial signals promptly returned following release of venous occlusion. Nine of these ten segments were viable at reoperation 24 hours later. In ten segments, no arterial signals could be detected following release of venous occlusion, and only one segment proved to be viable. Doppler ultrasound findings were far more accurate in distinguishing between viable and nonviable intestine thatn were clinical guides to intestinal viability. PMID:7352777

  6. Effectiveness of Pulse Oximetry Versus Doppler for Tourniquet Monitoring.

    Science.gov (United States)

    Wall, Piper L; Buising, Charisse M; Grulke, Lisa; Troester, Alexander; Bianchina, Nicholas; White, Shannon; Freymark, Rosemarie; Hassan, Ali; Hopkins, James W; Renner, Catherine Hackett; Sahr, Sheryl M

    Pulse oximeters are common and include arterial pulse detection as part of their methodology. The authors investigated the possible usefulness of pulse oximeters for monitoring extremity tourniquet arterial occlusion. Tactical Ratcheting Medical Tourniquets were tightened to the least Doppler-determined occluding pressure at mid-thigh or mid-arm locations on one limb at a time on all four limbs of 15 volunteers. A randomized block design was used to determine the placement locations of three pulse oximeter sensors on the relevant digits. The times and pressures of pulsatile signal absences and returns were recorded for 200 seconds, with the tourniquet being tightened only when the Doppler ultrasound and all three pulse oximeters had pulsatile signals present (pulsatile waveform traces for the pulse oximeters). From the first Doppler signal absence to tourniquet release, toe-located pulse oximeters missed Doppler signal presence 41% to 50% of the times (discrete 1-second intervals) and missed 39% to 49% of the pressure points (discrete 1mmHg intervals); fingerlocated pulse oximeters had miss rates of 11% to 15% of the times and 13% to 19% of the pressure points. On toes, the pulse oximeter ranges of sensitivity and specificity for Doppler pulse detection were 71% to 90% and 44% to 51%, and on fingers, the respective ranges were 65% to 77% and 78% to 83%. Use of a pulse oximeter to monitor limb tourniquet effectiveness will result in some instances of an undetected weak arterial pulse being present. If a pulse oximeter waveform is obtained from a location distal to a tourniquet, the tourniquet should be tightened. If a pulsatile waveform is not detected, vigilance should be maintained. 2017.

  7. The Doppler paradigm and the APEX-EPOS-ORANGE quandary

    International Nuclear Information System (INIS)

    Griffin, J.J.

    1995-01-01

    The experimental detection of the sharp lines of the (e + e - ) Puzzle is viewed as a struggle against Doppler broadening. Gedanken experiments which are realistic in zeroth order of detail are analyzed to show that the ORANGE and EPOS/I geometries select narrower slices of a Doppler broadened line than spherically inclusive (APEX and EPOS/II -like) apparati. Roughly speaking, the latter require event-by-event Doppler reconstruction simply to regain an even footing with the former. This suggests that APEX' or EPOS/II's coincident pair distributions must be statistically superior to those of EPOS/I or ORANGE in order to support a comparable inference about sharp structure. Under such circumstances, independent alternative data is invaluable. Therefore, a corroboration of Sakai's 330.1 keV ( + or e - bombardments of U and Th targets could prove crucial

  8. The duplex-Doppler colour echography of the scrotum and testicles in adults and boys. II. the contribution of the urgent study of acute scrotum symptoms; Ecografia duples-Doppler color del escroto y el testiculo en el adulto y el nino. II. Aportacion al estudio urgente del escroto agudo

    Energy Technology Data Exchange (ETDEWEB)

    Rangel-Villalobos, E.; Jimenez-Castellanos, R.; Bustos, C.; Linares, A.; Gonzalez-Prada, F. [Hospital Universitario Virgen Macarena. Sevilla (Spain)

    1999-07-01

    To analyse the findings, contributions and limitations of the Doppler echography for the urgent study of acute scrotum symptoms, both in adults and in boys. 60 patients (22 adults and 38 boys) with acute scrotal symptomatology were examined using B mode echography, followed by a colour duplex-Doppler (CDD) echography with a lineal 7.5 MHz transducer. We compared the findings obtained with those of the healthy contralateral testicle and with surgery or clinical-echographical evolution. The most common pathology was inflammation (27%) followed by ischemic (24%) and traumatic (17%). 12% of the patients had miscellaneous conditions. To conclude, in 20% of the cases the B mode and the Doppler examination was normal, the symptoms were resolved spontaneously. After carrying out the CDD only 14 (23%) of the cases needed immediate surgery and 3 (5%) delayed surgery, the remaining 43 (72%) patients responded to the traditional treatment. The CDD allows for a safe, quick and harmless diagnosis in practically all the acute scrotum cases, for both adults and boys. Its limitations in pre-puberty patients or in cases that were atypical are overcome when put in the hands of an expert radiologist, as they need a longer exploration time and suitable Doppler equipment. The main contribution to the urgent diagnosis of acute scrotum symptoms is that it accurately establishes which patients should be chosen for immediate surgery. (Author) 33 refs.

  9. Doppler reactivity uncertainties and their effect upon a hypothetical LOF accident

    International Nuclear Information System (INIS)

    Malloy, D.J.

    1976-01-01

    The statistical uncertainties and the major methodological errors which contribute to the Doppler feedback uncertainty were reviewed and investigated. Improved estimates for the magnitudes of each type of uncertainty were established. The generally applied reactivity feedback methodology has been extended by explicitly treating the coupling effect which exists between the various feedback components. The improved methodology was specifically applied to the coupling of Doppler and sodium void reactivities. In addition, the description of the temperature dependence of the Doppler feedback has been improved by the use of a two-constant formula on a global and regional basis. Feedback and coupling coefficients are presented as a first comparison of the improved and the currently applied methods. Further, the energy release which results from hypothetical disassembly accidents was simulated with a special response surface in the parametric safety evaluation code PARSEC. The impact of the improved feedback methodology and of Doppler coefficient uncertainties was illustrated by the usual parametric relationship between available work-energy and the Doppler coefficient. The work-energy was calculated with the VENUS-II disassembly code and was represented as a response surface in PARSEC. Additionally, the probability distribution for available work-energy, which results from the statistical uncertainty of the Doppler coefficient, was calculated for the current and the improved feedback methodology. The improved feedback description yielded about a 16 percent higher average value for the work-energy. A substantially larger increase is found on the high-yield end of the spectrum: the probability for work-energy above 500 MJ was increased by about a factor of ten

  10. Applications of Doppler-free saturation spectroscopy for edge physics studies (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Martin, E. H., E-mail: martineh@ornl.gov; Caughman, J. B. O.; Isler, R. C.; Bell, G. L. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Zafar, A. [Department of Nuclear Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2016-11-15

    Doppler-free saturation spectroscopy provides a very powerful method to obtain detailed information about the electronic structure of the atom through measurement of the spectral line profile. This is achieved through a significant decrease in the Doppler broadening and essentially an elimination of the instrument broadening inherent to passive spectroscopic techniques. In this paper we present the technique and associated physics of Doppler-free saturation spectroscopy in addition to how one selects the appropriate transition. Simulations of H{sub δ} spectra are presented to illustrate the increased sensitivity to both electric field and electron density measurements.

  11. The role of Doppler ultrasonography in the evaluation of the renal function

    International Nuclear Information System (INIS)

    Krasteva, R.; Kiperova, B.; Andreev, E.; Kostadinova, I.; Petrov, T.; Hadjidekov, V.; Simeonova, A.

    2008-01-01

    The purpose of the study was to evaluate Doppler ultrasonography in the detection of the renal function. Sixty six patients with unilateral kidney changes were enrolled in this prospective study. 16 had hypoplastic kidney, 24 had hypofunctioned kidney and 26 had afunctioned kidney. 15 healthy potential donors were controls. A dynamic renal scintigraphy was performed with 74-111 MBq 99mTc-MAG3. The Color, Pulsed and Power Doppler were performed. The Vp and δVp derived from the spectrum of the segmental arteries were measured during Pulsed Doppler examination. There are not any difference between kidneys of health and hypoplastic kidneys on color and Power Doppler. The hypofunctioning kidneys had reduced blood flow and afunctioning kidneys had markedly reduced blood flow. The Vp of donors (48.8±7.6) and Vp of hypoplastic kidneys (49.9±4.8) were significantly higher compared to Vp of hypofunctioning kidneys (31.6±10.0) and to Vp of afunctioning kidneys (26.6±9.1), (p 14.5 cm/s in 93%, and from hypofunctioning kidney by delta Vp>10.5 cm/s in 87%. The Doppler ultrasonography is very useful in the evaluation of renal function. The changes of the Doppler parameters accurately marked the loss of function which can not be detected by elevation of the creatinine level. (authors)

  12. Doppler derived gradient of ST Jude Mechanical Prosthesis, early postoperative assessment

    International Nuclear Information System (INIS)

    Shaikh, A.H.; Hanif, B.; Adil, A.; Hashimi, S.; Qazi, H.A.; Mujtaba, I.

    2010-01-01

    Objective: To determine the doppler derived mean gradients of St Jude mechanical prosthesis in early postoperative period in patients undergoing valve replacement at a tertiary care cardiac centre. Methods: Medical records of 190 consecutive patients who underwent 233 mitral, aortic or dual (mitral and aortic) valve replacement by St Jude bileaflet mechanical prosthesis at Tabba Heart Institute, between March 2006 to December 2008 were reviewed. Doppler derived mean gradients were assessed predischarge and recorded. Results: There were 98 (51.5%) males and 92 (48.5%) females in the study cohort. The mean age was 40 +- 14 years. Of the total, 101 (53%) had mitral, 46 (24.2%) had aortic and 43 (22.6%) patients had dual valve replacement. Doppler derived mean gradient was assessed across 144 mitral and 89 aortic St Jude mechanical prosthesis. Doppler derived mean gradient for St Jude mitral prosthesis was 3.5 mm Hg and for St Jude aortic prosthesis was 10.2 mm Hg. Conclusions: The study determines baseline gradients across mitral and aortic St Jude mechanical prosthesis in our population. These can be used as reference gradients to assess St Jude prosthetic valve function in patients who did not have early postoperative doppler assessment. (author)

  13. Analysis of placenta vascularization in patients with uterine altered artery Doppler flow velocity exams.

    Science.gov (United States)

    Gilio, Daniel Bruno; Miranda Corrêa, Rosana Rosa; Souza de Oliveira Guimarães, Camila; Peres, Luiz Cesar; Marques Salge, Ana Karina; Cavellani, Camila Lourencini; de Paula Antunes Teixeira, Vicente; Costa da Cunha Castro, Eumenia

    2009-08-01

    One of the frequent questions in obstetric practice is to determine placental vascular changes that may account for abnormal Doppler flow velocity alterations in maternal uterine vessels from women and fetuses without pregnancy pathology. A retrospective morphometric study was realized using 27 placentas from patients submitted for Doppler flow velocity exam during pregnancy. The placentas were morphologically examined using hematoxylin-eosin staining. Measurements of villi were made with the use of a video camera coupled to a common light microscope and a computer with automatic image analyzing software. Of the 27 placentas, 13 (48%) were of patients showing unaltered Doppler and 14 (52%) showing altered Doppler. The number of stem villi vessels was significantly larger in the placentas of patients with Doppler exam alterations (P = 0.003). This group also presented greater stem villi vessel thickness, although without significant difference. The number of intermediary and terminal villi vessels was greater in the placentas of patients with altered Doppler exams (P < 0.001), and a greater terminal villi area was observed in these cases (P < 0.001). The morphological proof that uterine artery Doppler flow velocity exam alterations are associated with placental vascular alterations demonstrates the importance of this exam during prenatal care, even in the absence of maternal-fetal alterations.

  14. Modeling and processing of laser Doppler reactive hyperaemia signals

    Science.gov (United States)

    Humeau, Anne; Saumet, Jean-Louis; L'Huiller, Jean-Pierre

    2003-07-01

    Laser Doppler flowmetry is a non-invasive method used in the medical domain to monitor the microvascular blood cell perfusion through tissue. Most commercial laser Doppler flowmeters use an algorithm calculating the first moment of the power spectral density to give the perfusion value. Many clinical applications measure the perfusion after a vascular provocation such as a vascular occlusion. The response obtained is then called reactive hyperaemia. Target pathologies include diabetes, hypertension and peripheral arterial occlusive diseases. In order to have a deeper knowledge on reactive hyperaemia acquired by the laser Doppler technique, the present work first proposes two models (one analytical and one numerical) of the observed phenomenon. Then, a study on the multiple scattering between photons and red blood cells occurring during reactive hyperaemia is carried out. Finally, a signal processing that improves the diagnosis of peripheral arterial occlusive diseases is presented.

  15. Endocarditis aórtica y pulmonar complicada con ictus hemorrágico: ¿cuál es el tiempo quirúrgico ideal?

    Directory of Open Access Journals (Sweden)

    Adrián Fernando Narvaez Muñoz

    2016-09-01

    Full Text Available Hombre de 77 años que presenta de forma súbita alteración del lenguaje y cambios de conducta; se realiza tomografía computarizada cerebral, en donde se observa hemorragia intraparenquimatosa frontal izquierda; su cuadro es acompañado de fiebre y hemocultivos positivos para Streptococcus bovis tipo i (gallolyticus. Se realiza un ecocardiograma transesofágico en donde se identifican vegetaciones a nivel de la válvula aortica y pulmonar; debido al contexto de su ictus hemorrágico, decidimos esperar al menos 4 semanas con tratamiento antibiótico antes de realizar cirugía. En la cirugía se resecó vegetación pulmonar y aórtica, realizándose recambio valvular aórtico metálico; la válvula pulmonar fue conservada. En el postoperatorio inmediato y mediato, el paciente presenta evolución favorable. El tratamiento antibiótico se continuó hasta la confirmación de los cultivos negativos de las válvulas extraídas. El ecocardiograma de control no mostró vegetaciones y el paciente fue dado de alta a su domicilio unos días después de su cirugía.

  16. Explanation of the Inverse Doppler Effect Observed in Nonlinear Transmission Lines

    International Nuclear Information System (INIS)

    Kozyrev, Alexander B.; Weide, Daniel W. van der

    2005-01-01

    The theory of the inverse Doppler effect recently observed in magnetic nonlinear transmission lines is developed. We explain the crucial role of the backward spatial harmonic in the occurrence of an inverse Doppler effect and draw analogies of the magnetic nonlinear transmission line to the backward wave oscillator

  17. Research on Fast-Doppler-Broadening of neutron cross sections

    International Nuclear Information System (INIS)

    Li, S.; Wang, K.; Yu, G.

    2012-01-01

    A Fast-Doppler-Broadening method is developed in this work to broaden Continuous Energy neutron cross-sections for Monte Carlo calculations. Gauss integration algorithm and parallel computing are implemented in this method, which is unprecedented in the history of cross section processing. Compared to the traditional code (NJOY, SIGMA1, etc.), the new Fast-Doppler-Broadening method shows a remarkable speedup with keeping accuracy. The purpose of using Gauss integration is to avoid complex derivation of traditional broadening formula and heavy load of computing complementary error function that slows down the Doppler broadening process. The OpenMP environment is utilized in parallel computing which can take full advantage of modern multi-processor computers. Combination of the two can reduce processing time of main actinides (such as 238 U, 235 U) to an order of magnitude of 1∼2 seconds. This new method is fast enough to be applied to Online Doppler broadening. It can be combined or coupled with Monte Carlo transport code to solve temperature dependent problems and neutronics-thermal hydraulics coupled scheme which is a big challenge for the conventional NJOY-MCNP system. Examples are shown to determine the efficiency and relative errors compared with the NJOY results. A Godiva Benchmark is also used in order to test the ACE libraries produced by the new method. (authors)

  18. Macroscopic effects in electromagnetically-induced transparency in a Doppler-broadened system

    International Nuclear Information System (INIS)

    Pei Li-Ya; Qu Yi-Zhi; Niu Jin-Yan; Wang Ru-Quan; Wu Ling-An; Fu Pan-Ming; Zuo Zhan-Chun

    2015-01-01

    We study the electromagnetically-induced transparency (EIT) in a Doppler-broadened cascaded three-level system. We decompose the susceptibility responsible for the EIT resonance into a linear and a nonlinear part, and the EIT resonance reflects mainly the characteristics of the nonlinear susceptibility. It is found that the macroscopic polarization interference effect plays a crucial role in determining the EIT resonance spectrum. To obtain a Doppler-free spectrum there must be polarization interference between atoms of different velocities. A dressed-state model, which analyzes the velocities at which the atoms are in resonance with the dressed states through Doppler frequency shifting, is employed to explain the results. (paper)

  19. Feasibility of UltraFast Doppler in Post-operative Evaluation of Hepatic Artery in Recipients following Liver Transplantation.

    Science.gov (United States)

    Kim, Se-Young; Kim, Kyoung Won; Choi, Sang Hyun; Kwon, Jae Hyun; Song, Gi-Won; Kwon, Heon-Ju; Yun, Young Ju; Lee, Jeongjin; Lee, Sung-Gyu

    2017-11-01

    To determine the feasibility of using UltraFast Doppler in post-operative evaluation of the hepatic artery (HA) after liver transplantation (LT), we evaluated 283 simultaneous conventional and UltraFast Doppler sessions in 126 recipients over a 2-mo period after LT, using an Aixplorer scanner The Doppler indexes of the HA (peak systolic velocity [PSV], end-diastolic velocity [EDV], resistive index [RI] and systolic acceleration time [SAT]) by retrospective analysis of retrieved waves from UltraFast Doppler clips were compared with those obtained by conventional spectral Doppler. Correlation, performance in diagnosing the pathologic wave, examination time and reproducibility were evaluated. The PSV, EDV, RI and SAT of spectral and UltraFast Doppler measurements exhibited excellent correlation with favorable diagnostic performance. During the bedside examination, the mean time spent for UltraFast clip storing was significantly shorter than that for conventional Doppler US measurements. Both conventional and UltraFast Doppler exhibited good to excellent inter-analysis consistency. In conclusion, compared with conventional spectral Doppler, UltraFast Doppler values correlated excellently and yielded acceptable pathologic wave diagnostic performance with reduced examination time at the bedside and excellent reproducibility. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  20. Testing the relativistic Doppler boost hypothesis for supermassive black hole binary candidates

    Science.gov (United States)

    Charisi, Maria; Haiman, Zoltán; Schiminovich, David; D'Orazio, Daniel J.

    2018-06-01

    Supermassive black hole binaries (SMBHBs) should be common in galactic nuclei as a result of frequent galaxy mergers. Recently, a large sample of sub-parsec SMBHB candidates was identified as bright periodically variable quasars in optical surveys. If the observed periodicity corresponds to the redshifted binary orbital period, the inferred orbital velocities are relativistic (v/c ≈ 0.1). The optical and ultraviolet (UV) luminosities are expected to arise from gas bound to the individual BHs, and would be modulated by the relativistic Doppler effect. The optical and UV light curves should vary in tandem with relative amplitudes which depend on the respective spectral slopes. We constructed a control sample of 42 quasars with aperiodic variability, to test whether this Doppler colour signature can be distinguished from intrinsic chromatic variability. We found that the Doppler signature can arise by chance in ˜20 per cent (˜37 per cent) of quasars in the nUV (fUV) band. These probabilities reflect the limited quality of the control sample and represent upper limits on how frequently quasars mimic the Doppler brightness+colour variations. We performed separate tests on the periodic quasar candidates, and found that for the majority, the Doppler boost hypothesis requires an unusually steep UV spectrum or an unexpectedly large BH mass and orbital velocity. We conclude that at most approximately one-third of these periodic candidates can harbor Doppler-modulated SMBHBs.

  1. Aortic isthmus Doppler velocimetry: role in assessment of preterm fetal growth restriction.

    LENUS (Irish Health Repository)

    Kennelly, M M

    2012-02-01

    Intrauterine fetal growth restriction (IUGR) is an important pregnancy complication associated with significant adverse clinical outcome, stillbirth, perinatal morbidity and cerebral palsy. To date, no uniformly accepted management protocol of Doppler surveillance that reduces mortality and cognitive morbidity has emerged. Aortic isthmus (AoI) evaluation has been proposed as a potential monitoring tool for IUGR fetuses. In this review, the current knowledge of the relationship between AoI Doppler velocimetry and preterm fetal growth restriction is reviewed. Relevant technical aspects and reproducibility data are reviewed as we discuss AoI Doppler and its place within the existing repertoire of Doppler assessments in placental insufficiency. The AoI is a link between the right and left ventricles which perfuse the lower and upper body, respectively. The clinical use of AoI waveforms for monitoring fetal deterioration in IUGR has been limited, but preliminary work suggests that abnormal AoI impedance indices are an intermediate step between placental insufficiency-hypoxemia and cardiac decompensation. Further prospective studies correlating AoI indices with arterial and venous Doppler indices and perinatal outcome are required before encorporating this index into clinical practice.

  2. Doppler-ultrasonographic finding of air in the portal vein: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ki Soon; Lee, Kwan Sup; Lee, Yul; Chung, Soo Young; Bae, Sang Hoon [College of Medicine, Hallym University, Seoul (Korea, Republic of)

    1994-03-15

    Classically air in the portal vein has been detected on plain radiography, but computed tomography and ultrasonography have been shown to be more sensitive. We report a case of air in the PV in a 10-day-old infant with pneumatosis intestinalis with its ultrasonographic and Doppler findings. The patient was a 10-day-old infant born by cesarean section at 41 weeks. Simple abdomen film revealed branching pattern of radiolucent air shadows within in contour of liver, gas distention of bowel loops and thickenod bowel walls with lincar intraluminal air shadows in abdomen, suggesting necrotizing enterocolitis. So we performed Doppler ultrasonography. Ultrasonography showed branching pattern of hyperechogenic dots and along the lumen of left portal vein. The color Doppler study revealed an aliasing duo to increased velocity and whirling pattern of blood flow, and the Duplex Doppler spectral display showed sharp, vertical bidirectional spikes by air in portal vein. Air in the portal vein can be easily diagnosed by the following signs: hyperechogenic dots in the portal vein on ultrasonography and vertical, sharp bidirectional spikes superimposed on the usual Doppler tracing of the portal vein on Duplex ultrasonography.

  3. Doppler-ultrasonographic finding of air in the portal vein: a case report

    International Nuclear Information System (INIS)

    Park, Ki Soon; Lee, Kwan Sup; Lee, Yul; Chung, Soo Young; Bae, Sang Hoon

    1994-01-01

    Classically air in the portal vein has been detected on plain radiography, but computed tomography and ultrasonography have been shown to be more sensitive. We report a case of air in the PV in a 10-day-old infant with pneumatosis intestinalis with its ultrasonographic and Doppler findings. The patient was a 10-day-old infant born by cesarean section at 41 weeks. Simple abdomen film revealed branching pattern of radiolucent air shadows within in contour of liver, gas distention of bowel loops and thickenod bowel walls with lincar intraluminal air shadows in abdomen, suggesting necrotizing enterocolitis. So we performed Doppler ultrasonography. Ultrasonography showed branching pattern of hyperechogenic dots and along the lumen of left portal vein. The color Doppler study revealed an aliasing duo to increased velocity and whirling pattern of blood flow, and the Duplex Doppler spectral display showed sharp, vertical bidirectional spikes by air in portal vein. Air in the portal vein can be easily diagnosed by the following signs: hyperechogenic dots in the portal vein on ultrasonography and vertical, sharp bidirectional spikes superimposed on the usual Doppler tracing of the portal vein on Duplex ultrasonography

  4. Ultrasonographic investigation of the Achilles tendon in elite badminton players using color Doppler.

    Science.gov (United States)

    Boesen, Morten Ilum; Boesen, Anders; Koenig, Merete Juhl; Bliddal, Henning; Torp-Pedersen, Soren

    2006-12-01

    The most frequent injuries in badminton players are in the lower extremities, especially in the Achilles tendon. The game of badminton may be related to abnormal intratendinous flow in the Achilles tendon as detected by color Doppler ultrasound. To a certain extent, this blood flow might be physiological, especially when examined after match. Cohort study (prevalence); Level of evidence, 3. Seventy-two elite badminton players were interviewed regarding Achilles tendon pain (achillodynia) in the preceding 3 years. Color Doppler was used to examine the tendons of 64 players before their matches and 46 players after their matches. Intratendinous color Doppler flow was graded from 0 to 4. The Achilles tendon was divided into dominant (eg, right side for right-handed players and vice versa) and nondominant side and classified as midtendon, preinsertional, and calcaneal areas. Of 72 players, 26 had experienced achillodynia in 34 tendons, 18 on the dominant side and 16 on the nondominant side. In 62% of the players with achillodynia, the problems had begun slowly, and the median duration of symptoms was 4 months (range, 0-36 months). Thirty-five percent had ongoing pain in their tendons for a median duration of 12 months (range, 0-12 months). Achillodynia was not associated with the self-reported training load or with sex, age, weight, singles or doubles players, or racket side. Forty-six players were scanned before and after match. At baseline, color Doppler flow was present in the majority of players, and only 7 (16%) players had no color Doppler flow in either tendon. After match, all players had some color Doppler flow in 1 or both tendons. Achillodynia and color Doppler flow were related in the nondominant Achilles tendon (chi-square, P = .008). The grades of Doppler flow also increased significantly after match in the preinsertional area in both the nondominant (P = .0002) and dominant (P = .005) side tendons. A large proportion of the players had experienced

  5. Effect of Doppler flow meter position on discharge measurement in surcharged manholes.

    Science.gov (United States)

    Yang, Haoming; Zhu, David Z; Liu, Yanchen

    2018-02-01

    Determining the proper installation location of flow meters is important for accurate measurement of discharge in sewer systems. In this study, flow field and flow regimes in two types of manholes under surcharged flow were investigated using a commercial computational fluid dynamics (CFD) code. The error in measuring the flow discharge using a Doppler flow meter (based on the velocity in a Doppler beam) was then estimated. The values of the corrective coefficient were obtained for the Doppler flow meter at different locations under various conditions. Suggestions for selecting installation positions are provided.

  6. Correlation between Doppler flow patterns in growth-restricted fetuses and neonatal circulation

    NARCIS (Netherlands)

    Tanis, J. C.; Boelen, M. R.; Schmitz, D. M.; Casarella, L.; van der Laan, M. E.; Bos, A. F.; Bilardo, C. M.

    Objectives To investigate whether prenatal Doppler parameters in growth-restricted fetuses are correlated with neonatal circulatory changes. Methods In 43 cases of suspected fetal growth restriction (FGR), serial Doppler measurements of umbilical artery (UA) and middle cerebral artery (MCA)

  7. Role of Doppler US and MRI in diagnosis of placenta accreta ...

    African Journals Online (AJOL)

    The aim of this work is to evaluate the role of Doppler US and MRI in the diagnosis of placenta accreta. Patients and methods: During period between 2012 to 2013, 120 pregnant patients with previous cesarean section were investigated by ultrasound and Doppler and then in suspected cases MRI was obtained (10 cases).

  8. Kan Doppler-ultralyd erstatte strain gauge til måling af systolisk ankelblodtryk?

    DEFF Research Database (Denmark)

    Sørensen, T L; Perner, A; Hansen, L

    1992-01-01

    Traditionally, strain gauge technique is used in Denmark to measure ankle blood pressure, a method requiring both time and well-trained personnel. In a study involving 90 limbs in 45 patients, this method was compared with ultrasonic technique using a portable 5 MHz Doppler. The reproducibility...... of Doppler ankle pressure measurement was similar to that found in strain gauge based studies. Two consecutive measurements may differ by 20 mmHg or in terms of ankle-brachial index by 0.15 before this is considered significant. No systematic variation was found between the two methods. Increasing...... difficulties were encountered with the Doppler technique at pressures below 50 mmHg. It is concluded that Doppler is a good alternative to strain gauge for measurement of ankle blood pressure....

  9. Transcranial Doppler Ultrasound in Peninsular Arab Patients With Sickle Cell Disease.

    Science.gov (United States)

    Adekile, Adekunle; Hassan, Meaad; Asbeutah, Akram; Al-Hinai, Mohamed; Trad, Omar; Farhan, Nayef

    2018-05-06

    Transcranial Doppler ultrasound is used to identify patients with sickle cell disease (SCD) at risk for stroke. We performed transcranial Doppler studies in patients from 4 countries in the Arabian Peninsula (Kuwait, Oman, Iraq, and United Arab Emirates) to document the prevalence of abnormal transcranial Doppler findings. The patients were recruited from outpatient clinics and studied in a steady state. Transcranial Doppler examinations were performed with standard equipment by experienced operators. The time-averaged maximum mean velocity (TAMMV) was documented in the arteries of the circle of Willis. The hemoglobin (Hb) genotype was confirmed, and the fetal Hb level and complete blood counts were determined. There were 415 patients in the study, aged 2 to 18 years (mean ± SD, 8.6 ± 3.5 years). None of the patients had an abnormal TAMMV (ie, > 200 cm/s), whereas only 13 (3.1%), all from Iraq, had conditional values (170-200 cm/s) in the right middle cerebral artery and 7 (1.7%) in the left middle cerebral artery. There were no consistent TAMMV differences among male and female patients or in patients with different Hb genotypes (sickle cell anemia, sickle cell β 0- thalassemia, and sickle D). The use of hydroxyurea was associated with a lower TAMMV, whereas a blood transfusion history had no influence. Total hemoglobin, reticulocyte count, serum bilirubin, and fetal Hb values showed varying degrees of association with the TAMMV in the different vessels. This study has demonstrated the rarity of abnormal transcranial Doppler findings among Peninsular Arab patients with SCD. The guidelines for transcranial Doppler screening in this population need further studies and recommendations. © 2018 by the American Institute of Ultrasound in Medicine.

  10. Doppler echocardiographic predictors of mortality in female rats after myocardial infarction.

    Science.gov (United States)

    Santos, Alexandra Alberta; Helber, Izzo; Flumignan, Ronald L G; Antonio, Ednei L; Carvalho, Antonio C; Paola, Angelo A; Tucci, Paulo J; Moises, Valdir A

    2009-03-01

    Doppler echocardiogram is useful for the evaluation of anatomical and functional changes in late myocardial infarction (MI) in rats. However, no studies have evaluated the prognostic value of echocardiographic parameters 1 week after MI. Doppler echocardiogram was performed in 84 female Wistar rats 1 week after MI to determine infarction size, left chambers dimensions, fractional area change (FAC) of the left ventricle (LV), mitral inflow and tissue Doppler, myocardial performance index (MPI), and signs of pulmonary hypertension. The 365-day follow-up showed 53.6% mortality rate. Nonsurvivors showed larger (P or=0.60 (RR 3.49, 95% CI, 1.80-6.76), LV systolic area >or=0.26 cm(2) (RR 4.38, 95% CI, 1.88-10.21), E/E' ratio >or=20.3 (RR 2.12, 95% CI, 1.15-4.34), and E/A ratio associated with FAC (RR 2.99, 95% CI, 1.44-6.18). Some diastolic and systolic Doppler echocardiographic parameters in rats may be able to predict late mortality risk after MI.

  11. Computer-assisted quantitative assessment of power Doppler US: effects of microbubble contrast agent in the differentiation of breast tumors

    International Nuclear Information System (INIS)

    Kettenbach, Joachim; Helbich, Thomas H.; Huber, Sabine; Zuna, Ivan; Dock, Wolfgang

    2005-01-01

    Rationale and objectives: To objectively quantify the effects of a microbubble contrast agent to differentiate breast tumors with power doppler ultrasound and to compare these results with color doppler ultrasound (CD US). Methods: In 47 patients a microbubble contrast agent was injected intravenously. Computer-assisted quantitative assessment of the color pixel density was performed to evaluate the increase in Doppler signals. Results were compared to previously published results of a color Doppler ultrasound study. Results: Peak color pixel density at contrast-enhanced power Doppler ultrasound was higher for carcinomas than for benign tumors (P < 0.03). Time to peak enhancement was shorter in carcinomas than in benign tumors (P < 0.01). For both parameters, diagnostic accuracy of power Doppler ultrasound was 69 and 78%, and for color Doppler ultrasound 62 and 76%, respectively. Conclusions: Quantitative assessment of contrast-enhanced power Doppler ultrasound showed significant differences in malignant and benign breast tumors. Diagnostic accuracy of contrast-enhanced power Doppler ultrasound was higher compared to color Doppler ultrasound

  12. Doppler effect measurement in FCA assemblies X-3 and XI-1

    International Nuclear Information System (INIS)

    Okajima, Shigeaki; Mukaiyama, Takehiko

    1984-05-01

    Doppler reactivity worths were measured in FCA assemblies X-3 (mock-up core for JOYO Mark II) and XI-1 (mock-up core for large scale LMFBR) for U-238 and stractural materials of core (iron, stainless steel and nickel). The sample oscillation technique was used to measure the Doppler effect when a sample is heated up to 800 0 C from room temperature. The analysis was made using the 70 group JFS-3-J2 data set, and compared with the measured results. For U-238 samples, the calculation underestimates Doppler effects by 10%, on the other hand for other samples, the agreement between calculated values and measured values is quite good. (author)

  13. Vesico-ureteral reflux: diagnosis and staging with voiding color doppler US Preliminary experience

    International Nuclear Information System (INIS)

    Farina, Renato; Arena, Carmela; Pennisi, Francesco; Di Benedetto, Vincenzo; Politi, Guido; Di Benedetto, Aurelio

    2000-01-01

    Introduction: The aim of this study is to assess the accuracy of a new US examination: 'voiding color Doppler US ' in the early diagnosis and staging of vesico-ureteral reflux (VUR). The contrast agent US was SH U 508A (Levovist, Schering, Berlin), which produces a chromatic accentuation of the signals picked up by the color Doppler US. Eighteen patients (10 females, eight males) were recruited for the study. In two patients a second examination was performed for follow-up after a VUR conservative therapy. All patients were taken under examination for the evaluation of possible VUR. In all patients the voiding color Doppler US was followed by voiding cystourethrography (VCUG) and the data obtained were compared. Materials and methods: A total of 18 patients aged between 3 months and 10 years, were recruited for the study. The results of the examination were the following: urinary tract infections, follow-up of VUR after conservative or surgical therapy, miscellaneous indications. Voiding color Doppler US was performed, followed by a VCUG. The voiding color Doppler US consists in the trans-catheter introduction of a contrast agent SHU 508 A (Levovist, Schering, Ag. Berlin) into the bladder and a subsequent test with the color Doppler US to show or exclude the presence of reflux into the ureters and/or into the pyelo-caliceal cavity of the kidneys. After the introduction of the contrast agent US the ultrasound scanning of the bladder, the ureters and the pyelo-caliceal cavity was performed to examine the reflux degree. The ultrasonographic investigations were perfomed with AU 590 asyncronus US (Esaote Biomedica, Genova) with a 3.5 MHz convex probe. Results: After the trans-catheter introduction of the contrast agent US, vesico-ureteral reflux occured in 13 patients (77.2%). The reflux degree was also measured by means of ultrasound and was later confirmed by VCUG. The mean times of each examination were as follows: initial US, 10 min; catheterization, 8 min; voiding

  14. Application of Energy Window Concept in Doppler Broadening of {sup 238}U Cross Section

    Energy Technology Data Exchange (ETDEWEB)

    Khassnov, Azamat; Choi, Soo Young; Lee, Deok Jung [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2014-10-15

    Currently, the NJOY code is used for construction and Doppler broadening of microscopic cross sections. There exist several methods or formalisms to produce microscopic cross sections and there are also different methods of Doppler broadening. In this paper, Multi-Level Breit-Wigner (MLBW) formalism and the Psi method are used for generation and Doppler broadening of the resonance cross section. Accuracy of the energy window concept applied MLBW (EW MLBW) Doppler broadened cross section was compared with that of the cross section generated by conventional MLBW (Con MLBW) formalism for {sup 2}38U isotope using MATLAB. The conventional method requires Doppler broadening of all resonances, including resonances far from the target energy point, which do not change much with respect to the temperature change. The energy window concept makes Doppler broadening possible with a smaller number of resonances neighboring to the energy point we are interested in, and just adds up 0 K temperature cross sections of other resonances. Multi-level Breit-Wigner formalism and the Doppler broadening method were used to construct microscopic cross sections of {sup 238}U at different temperatures. The energy window concept was applied only for the 1st resonance energy region (4.5∼11.2 eV). The energy window concept demonstrates high competitiveness because the relative differences were less than 0.0016% for all types of cross sections. The advantage of the energy window concept is that the number of resonances broadened for every energy point is significantly reduced, which allows a reduction of computation time by almost 45 % of Doppler broadening time of the cross section generation at temperatures higher than 0 K.

  15. On the Fly Doppler Broadening Using Multipole Representation

    International Nuclear Information System (INIS)

    Khassenov, Azamat; Choi, Sooyoung; Lee, Deokjung

    2015-01-01

    On the Fly Doppler broadening is the technique to avoid pre-generation of the microscopic cross section, in other words, reduce the amount of storage. Currently, there are different types of formalisms used by NJOY code to generate reaction cross section and accomplish its Doppler broadening. Single-Level Breit-Wigner (SLBW) formalism is limited to well-separated resonances, in other words, it does not consider interference between energy levels. Multi-Level Breit- Wigner formalism (MLBW) was tested as the candidate for the cross section generation in the Monte Carlo code, which is under development in UNIST. According to the results, MLBW method requires huge amount of computational time to produce cross section at certain energy point. Reich-Moore (RM) technique can generate only 0K cross section, which means that it cannot produce broaden cross section directly from resonance parameters. The first step was to convert resonance parameters given in nuclear data file into multipoles. MPR shows very high potential to be used as the formalism in the on-the-fly Doppler broadening module of MCS. One of the main reasons is that comparison of the time cost shown in Table IV supports application of multipole representation

  16. Doppler ultrasound study of penis in men with systemic sclerosis: a correlation with Doppler indices of renal and digital arteries.

    Science.gov (United States)

    Rosato, E; Barbano, B; Gigante, A; Cianci, R; Molinaro, I; Quarta, S; Digiulio, M A; Messineo, D; Pisarri, S; Salsano, F

    2013-01-01

    Erectile dysfunction (ED) prevalence in male systemic sclerosis (SSc) is high and its pathogenesis is unclear. The aim of the study is to assess correlation between Doppler ultrasound indices of penis and kidneys or digital arteries in male systemic sclerosis. Fourteen men with systemic sclerosis were enrolled in this study. Erectile function was investigated by the International Index of Erectile Function-5. Peak systolic velocity, end diastolic velocity, resistive index, pulsative index, and systolic/diastolic ratio were measured on the cavernous arteries at the peno-scrotal junction in the flaccid state, on the interlobar artery of both kidneys and all ten proper palmar digital arteries. Ten (71 percent) patients have an International Index of Erectile Function-5 less than 21. Reduction of penis peak systolic velocity was observed in all SSc subjects. Doppler indices of cavernous arteries correlate with the International Index of Erectile Function-5. The renal and digital arteries resistive index demonstrated a good correlation (p less than 0.0001) with International Index of Erectile Function-5. A positive correlation exists between penis and kidney arteries Doppler indices: end diastolic velocity (p less than 0.05, r=0.54), resistive index (p less than 0.0001, r=0.90), systolic/diastolic ratio (p less than 0.01, r=0.69). A positive correlation was observed between penis and digital arteries Doppler indices: peak systolic velocity (p less than 0.01, r=0.68), end diastolic velocity (p less than 0.01, r=0.75), resistive index (p less than 0.001, r=0.79), systolic/diastolic ratio (p less than 0.05, r=0.59). A correlation exists between arterial impairment of penis and renal or digital arteries.

  17. An ocean current inversion accuracy analysis based on a Doppler spectrum model

    Institute of Scientific and Technical Information of China (English)

    BAO Qingliu; ZHANG Youguang; LIN Mingsen; GONG Peng

    2017-01-01

    Microwave remote sensing is one of the most useful methods for observing the ocean parameters.The Doppler frequency or interferometric phase of the radar echoes can be used for an ocean surface current speed retrieval,which is widely used in spaceborne and airborne radars.While the effect of the ocean currents and waves is interactional.It is impossible to retrieve the ocean surface current speed from Doppler frequency shift directly.In order to study the relationship between the ocean surface current speed and the Doppler frequency shift,a numerical ocean surface Doppler spectrum model is established and validated with a reference.The input parameters of ocean Doppler spectrum include an ocean wave elevation model,a directional distribution function,and wind speed and direction.The suitable ocean wave elevation spectrum and the directional distribution function are selected by comparing the ocean Doppler spectrum in C band with an empirical geophysical model function (CDOP).What is more,the error sensitivities of ocean surface current speed to the wind speed and direction are analyzed.All these simulations are in Ku band.The simulation results show that the ocean surface current speed error is sensitive to the wind speed and direction errors.With VV polarization,the ocean surface current speed error is about 0.15 m/s when the wind speed error is 2 m/s,and the ocean surface current speed error is smaller than 0.3 m/s when the wind direction error is within 20° in the cross wind direction.

  18. Fresh look at the doppler changes in pregnancies with placental-based complications

    Directory of Open Access Journals (Sweden)

    S Dikshit

    2011-01-01

    Full Text Available Placental-based complications of pregnancy can be classified as acute and chronic. An example of acute placental complication is abruptio placenta. The chronic placental complications include pregnancy induced hypertension (PIH and idiopathic Intrauterine growth restriction (IUGR. The fetus is at risk for perinatal complications in both acute and chronic conditions. Here we take a look at the natural history of the Doppler parameters in chronic conditions. The techniques used for assessing the fetal well-being include, clinical methods, biophysical tests, conventional ultrasonography, and fetal Doppler studies. Arterial Doppler studies are used to assess the well-being of the fetus and to determine the timing of delivery. However, arterial Dopplers predict only the subset of fetuses at risk of having perinatal complications. Venous Dopplers have been used to improve upon the prognostication. However, by the time the commonly used venous Doppler signs, that is, ′A′ wave reversal in ductus venosus (DV is present, the fetus is likely to be already compromised. The fetus tries to adapt to the environment of deprivation by making a series of changes in the umbilical artery circulation, cerebral circulation, and hepatic circulation. As a result of these adaptations, the fetus overcomes the state of chronic hypoxia. This article takes a look at these changes and also the effect of these adaptations. It is suggested that serial comparisons of the venous flow characteristics of the DV and inferior vena cava (IVC can provide an early indication of the impending decompensation and can be used to predict the time the delivery.

  19. Doppler color flow mapping of peripheral vessels: Comparison of angiodynography with conventional duplex US

    International Nuclear Information System (INIS)

    Merritt, C.R.B.; Bluth, E.I.; Sullivan, M.A.

    1986-01-01

    A new Doppler color flow imager was compared to duplex US in the evaluation of carotid and peripheral vessels in 50 patients. A 7.5-MHz transducer permitted simultaneous high-resolution real-time imaging of Doppler flow and tissue. The system was found to have excellent image quality and Doppler sensitivity. Flow characteristics and velocity measurements obtained with this system correlated well with those obtained using the duplex scanner and were obtained more quickly than with the conventional system, allowing more complete assessment of flow characteristics. Color Doppler flow imaging appears to be an extremely promising method for the rapid and effective evaluation of peripheral vascular flow

  20. Contrast-enhanced power Doppler US of hepatocellular carcinomas: Quantitative analysis

    International Nuclear Information System (INIS)

    Kim, Ah Young; Choi, Byung Ihn; Kim, Tae Kyoung; Lee, Kyoung Ho; Han, Joon Koo

    1999-01-01

    To determine peak time and duration of contrast enhancement of nodular hepatocellular carcinoma (HCC) on contrast-enhancement power Doppler ultrasound (US) with Levovist by quantitative analysis. Twenty eight patients with nodular HCC were prospectively evaluated with power Doppler US by one examiner. Serial images were obtained before and after injection of 300 mg/mL US contrast agent (SH U 508 A, Levovist, Schering) with the injection rate of 0.2 mL/sec. Power Doppler signals on obtained digital images were quantified using 'Ultrasound Imaging Tool Version 1.0' (Seoul, Korea). The grade, peak time and duration of contrast enhancement of the tumors were analyzed. For nodular HCCs, mean peak enhancement time was 60 seconds after injection of Levovist (mean enhanced area 41.6 ± 28.6 %). These tumoral enhancement decreased from 90 seconds and returned to near baseline state at 5 minutes after injection of Levovist. Maximum enhanced areas (%) were variable at a range of 8-98.5% and mean maximum enhanced area was 46.4 ± 28.6%. On contrast-enhanced power Doppler US with Levovist, nodular HCCs showed peak contrast enhancement (41.6± 28.6) at 60 seconds after injection of contrast agent. This tumoral enhancement nearly disappeared at 5 minutes after injection of contrast agent.

  1. Method and system of doppler correction for mobile communications systems

    Science.gov (United States)

    Georghiades, Costas N. (Inventor); Spasojevic, Predrag (Inventor)

    1999-01-01

    Doppler correction system and method comprising receiving a Doppler effected signal comprising a preamble signal (32). A delayed preamble signal (48) may be generated based on the preamble signal (32). The preamble signal (32) may be multiplied by the delayed preamble signal (48) to generate an in-phase preamble signal (60). The in-phase preamble signal (60) may be filtered to generate a substantially constant in-phase preamble signal (62). A plurality of samples of the substantially constant in-phase preamble signal (62) may be accumulated. A phase-shifted signal (76) may also be generated based on the preamble signal (32). The phase-shifted signal (76) may be multiplied by the delayed preamble signal (48) to generate an out-of-phase preamble signal (80). The out-of-phase preamble signal (80) may be filtered to generate a substantially constant out-of-phase preamble signal (82). A plurality of samples of the substantially constant out-of-phase signal (82) may be accumulated. A sum of the in-phase preamble samples and a sum of the out-of-phase preamble samples may be normalized relative to each other to generate an in-phase Doppler estimator (92) and an out-of-phase Doppler estimator (94).

  2. Three-dimensional Doppler ultrasound findings in healthy wrist and finger tendon sheaths

    DEFF Research Database (Denmark)

    Ammitzboll-Danielsen, Mads; Janta, Iustina; Torp-Pedersen, Søren

    2016-01-01

    interpretation of Doppler signals when diagnosing tenosynovitis. Method Forty healthy participants (20 women and 20 men age 23-67 years) without prior history of arthritis, tendon diseases or present pain in their hands were included. Twenty participants had 3D Doppler US of the second and third finger...... participant. No significant difference in feeding vessels was seen between the radial and carpal level in the wrist (p = 0.06) or between the second and third flexor tendon sheath (p = 0.84). Conclusion Doppler findings in or in close proximity to the tendon sheaths were common in wrists and fingers...

  3. Laser sub-Doppler cooling of atoms in an arbitrarily directed magnetic field

    International Nuclear Information System (INIS)

    Chang, Soo; Kwon, Taeg Yong; Lee, Ho Seong; Minogin, V.G.

    2002-01-01

    We analyze the influence of an arbitrarily directed uniform magnetic field on the laser sub-Doppler cooling of atoms. The analysis is done for a (3+5)-level atom excited by a σ + -σ - laser field configuration. Our analysis shows that the effects of the magnetic field depend strongly on the direction of the magnetic field. In an arbitrarily directed magnetic field the laser cooling configuration produces both the main resonance existing already at zero magnetic field and additional sub-Doppler resonances caused by two-photon and higher-order multiphoton processes. These sub-Doppler resonances are, however, well separated on the velocity scale if the Zeeman shift exceeds the widths of the resonances. This allows one to use the main sub-Doppler resonance for an effective laser cooling of atoms even in the presence of the magnetic field. The effective temperature of the atomic ensemble at the velocity of the main resonance is found to be almost the same as in the absence of the magnetic field. The defined structure of the multiphoton resonances may be of importance for the sub-Doppler laser cooling of atoms, atomic extraction from magneto-optical traps, and applications related to the control of atomic motion

  4. Optimized variational analysis scheme of single Doppler radar wind data

    Science.gov (United States)

    Sasaki, Yoshi K.; Allen, Steve; Mizuno, Koki; Whitehead, Victor; Wilk, Kenneth E.

    1989-01-01

    A computer scheme for extracting singularities has been developed and applied to single Doppler radar wind data. The scheme is planned for use in real-time wind and singularity analysis and forecasting. The method, known as Doppler Operational Variational Extraction of Singularities is outlined, focusing on the principle of local symmetry. Results are presented from the application of the scheme to a storm-generated gust front in Oklahoma on May 28, 1987.

  5. Method and apparatus for Doppler frequency modulation of radiation

    Science.gov (United States)

    Margolis, J. S.; Mccleese, D. J.; Shumate, M. S.; Seaman, C. H. (Inventor)

    1980-01-01

    A method and apparatus are described for frequency modulating radiation, such as from a laser, for optoacoustic detectors, interferometers, heterodyne spectrometers, and similar devices. Two oppositely reciprocating cats-eye retroreflectors are used to Doppler modulate the radiation. By reciprocally moving both retroreflectors, the center of mass is maintained constant to permit smooth operation at many Hertz. By slightly offsetting the axis of one retroreflector relative to the other, multiple passes of a light beam may be achieved for greater Doppler shifts with the same reciprocating motion of the retroreflectors.

  6. Analysis of multiple scattering effects in optical Doppler tomography

    DEFF Research Database (Denmark)

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

    2005-01-01

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

  7. Calculation results and experimental testing of doppler feedback coefficients

    International Nuclear Information System (INIS)

    Yang Shunhai

    1989-01-01

    The Doppler feedback coefficients are calculated by the interpolation and group collapsing method from multigroup self-shielding factors and infinite dilution cross sections rather than effective resonance integrals by using resonance data base. Since many updated sets of multigroup data are in existence to be selected, the calculation process can be simplified. The heterogeneous effects are taken into account by equivalence relation. The computer code of Doppler feedback coefficients is created on computer CYBER-825 and PDP-11. The results calculated are in good agreement with the experiments

  8. The use of contrast-enhanced color doppler ultrasound in the differentiation of retinal detachment from vitreous membrane

    International Nuclear Information System (INIS)

    Han, Sang Suk; Chang, Seung Kook; Yoon, Jung Hee; Lee, Young Joon

    2001-01-01

    To compare the clinical utility of contrast-enhanced color Doppler US in the differentiation of retinal detachment (RD) from vitreous membrane (VM) with that of various conventional US modalities, and to analyze the enhancement patterns in cases showing an enhancement effect. In 32 eyes examined over a recent two-year period, RD (n=14) and VM (n=18) were confirmed by surgery (n=28) or clinical follow-up (n=4). In all cases, gray-scale, color Doppler, and power Doppler US were performed prior to contrast injection, and after the intravenous injection of Levovist (Schering, Berlin) by hand for 30 seconds at a dose of 2.5 g and a concentration of 300 mg/mL via an antecubital vein, contrast-enhanced color Doppler US was performed. At Doppler US, the diagnostic criterion for RD and VM was whether or not color signals were visualized in membranous structures. Diagnostic accuracy was 78% at gray-scale US, 81% at color Doppler US, 59% at power Doppler US, and 97% at contrast-enhanced color Doppler US. The sensitivity of color Doppler US to color signals in RD increased from 57% to 93% after contrast enhancement. The enhancement patterns observed were signal accentuation (n=3), signal extension (n=2), signal addition (n=3), and new signal visualization (n=5). Contrast-enhanced color Doppler US was the most accurate US modality for differentiating RD from VM, showing a significantly increased signal detection rate in RD

  9. Laser Doppler thermometry in flat flames

    NARCIS (Netherlands)

    Maaren, van A.; Goey, de L.P.H.

    1994-01-01

    Laser Doppler Velocimetry measurements are performed in flat flames, stabilized on a newly developed flat-flame burner. It is shown that the velocity component perpendicular to the main flow direction, induced by expansion in the reaction zone and buoyancy in the burnt gas, is significant. A method

  10. Renal duplex Doppler ultrasound findings in diabetics

    International Nuclear Information System (INIS)

    Shim, Hyang Yee; Kim, Young Geun; Kook, Cheol Keu; Yoon, Chong Hyun; Lee, Shin Hyung; Lee, Chang Joon

    1993-01-01

    The correlation between clinical-laboratory findings and renal duplex Doppler ultrasound findings was studied in 45 patients with diabetes mellitus to see the role of duplex Doppler ultrasound in the detection of diabetic nephropathy. The resistive indices in patients with elevated serum creatinine, BUN, proteinuria, and systolic blood pressure levels were statistically significantly higher than those in patients with normal levels (p<0.05). Also resistive indics in patients with retinopathy were higher than that in patients without retinopathy (p<0.05). But the ultrasound morphologic changes of kidney such as renal length, cortical eye-catching, and corticomedullarycontrast were not well correlated with clinical-laboratory data and resistive index. The resistive index of the kidney in conjunction with clinical-laboratory data in diabetics may be helpful in the evaluation of diabetic nephropathy

  11. Renal duplex Doppler ultrasound findings in diabetics

    Energy Technology Data Exchange (ETDEWEB)

    Shim, Hyang Yee; Kim, Young Geun; Kook, Cheol Keu; Yoon, Chong Hyun; Lee, Shin Hyung; Lee, Chang Joon [National Medical Center, Seoul (Korea, Republic of)

    1993-12-15

    The correlation between clinical-laboratory findings and renal duplex Doppler ultrasound findings was studied in 45 patients with diabetes mellitus to see the role of duplex Doppler ultrasound in the detection of diabetic nephropathy. The resistive indices in patients with elevated serum creatinine, BUN, proteinuria, and systolic blood pressure levels were statistically significantly higher than those in patients with normal levels (p<0.05). Also resistive indics in patients with retinopathy were higher than that in patients without retinopathy (p<0.05). But the ultrasound morphologic changes of kidney such as renal length, cortical eye-catching, and corticomedullarycontrast were not well correlated with clinical-laboratory data and resistive index. The resistive index of the kidney in conjunction with clinical-laboratory data in diabetics may be helpful in the evaluation of diabetic nephropathy

  12. The color Doppler ultrasonography in in the diagnosis of deep vein thrombosis

    International Nuclear Information System (INIS)

    Ameneiro Perez, Santiago; Alvarez Sanchez, Jose A.; Rodriguez Villalonga, Luis; Borras Migues, Marisela; Quinnones Castro, Mayda

    2004-01-01

    The paper was aimed at evaluating the accuracy of color Doppler ultrasonography, a noninvasive method, in the diagnosis of deep vein thrombosis of the lower limbs, comparing it to the results of the cruel and costly diagnostic g olden rule , that is, phlebography. Methods: Color Doppler ultrasonography served to assess 102 patients clinically suspected of deep vein thrombosis of the lower limbs, taking into account the following criteria: vein compressibility, echographic images, color, Vein Doppler signal modulation after several maneuvers and distal compression. Sensitivity, specificity, positive and negative predictive values and diagnostic efficacy were estimated for each criteria, taking the phlebography as a reference. Results: Total or partial lack of vein compressibility combined with the vein flow evaluation is the ultrasonographic criterion that reveals higher degree of sensitivity, specificity and efficacy (0,98; 0,95 and 0,97 respectively. Color Doppler ultrasonography is a highly effective noninvasive diagnostic method that detects deep vein thrombosis in proximal areas of the lower limbs

  13. Accuracy of doppler ultrasound in diagnosis of endometrial carcinoma

    International Nuclear Information System (INIS)

    Batool, S.; Raza, S.; Manzur, S.

    2013-01-01

    Objective: To determine the accuracy of Doppler ultrasound in the diagnosis of endometrial carcinoma in patients presenting with post-menopausal bleeding while taking histopathological findings as the gold standard. Methods: The cross-sectional study was done at the Department of Radiology, Bahawal Victoria Hospital, Bahawalpur, from April 1 to September 30, 2009, and comprised 128 patients above 50 years of age having history of post-menopausal bleeding and who were referred to the department. Name, age and hospital registration number were recorded on a proforma. Doppler ultrasound was performed and endometrial thickness and uterine artery resistive index were recorded on transabdominal ultrasonography. Patients with endometrial thickness of more than 5mm and uterine artery resistive index of less than 0.7 were considered to be having endometrial carcinoma. Histopathology findings were also recorded using the hospital registration number of the patient. The findings of Doppler ultrasound scan were validated with the findings of histopathology. Results: Of the 128 patients, 48 (37.5%) were between the ages of 51 and 55 years; 46 (35.93%) were in the 56-60 age group; and 34 (26.57%) were over 65 years. On the basis of Doppler ultrasound findings, 106 (82.8%) patients were diagnosed as having endometrial carcinoma, while 22 (17.19%) were declared negative. Ultrasonography results were compared with histopathology findings. The percentages of true positive, true negative, false positive and false negative were calculated. There were 103 (80.47%) true positive; 12 (9.37%) false positive; 10 (7.81%) true negative; and 3 (2.35%) false negative. Specificity, sensitivity, positive predictive value and negative predictive value were found to be 97.16%, 76%, 89.56% and 76.92% respectively. Conclusion: The use of Doppler ultrasonography in non-invasive diagnosis of endometrial carcinoma in patients presenting with post-menopausal bleeding was quite useful with good

  14. Operator auditory perception and spectral quantification of umbilical artery Doppler ultrasound signals.

    Directory of Open Access Journals (Sweden)

    Ann Thuring

    Full Text Available OBJECTIVE: An experienced sonographer can by listening to the Doppler audio signals perceive various timbres that distinguish different types of umbilical artery flow despite an unchanged pulsatility index (PI. Our aim was to develop an objective measure of the Doppler audio signals recorded from fetoplacental circulation in a sheep model. METHODS: Various degrees of pathological flow velocity waveforms in the umbilical artery, similar to those in human complicated pregnancies, were induced by microsphere embolization of the placental bed (embolization model, 7 lamb fetuses, 370 Doppler recordings or by fetal hemodilution (anemia model, 4 lamb fetuses, 184 recordings. A subjective 11-step operator auditory scale (OAS was related to conventional Doppler parameters, PI and time average mean velocity (TAM, and to sound frequency analysis of Doppler signals (sound frequency with the maximum energy content [MAXpeak] and frequency band at maximum level minus 15 dB [MAXpeak-15 dB] over several heart cycles. RESULTS: WE FOUND A NEGATIVE CORRELATION BETWEEN THE OAS AND PI: median Rho -0.73 (range -0.35- -0.94 and -0.68 (range -0.57- -0.78 in the two lamb models, respectively. There was a positive correlation between OAS and TAM in both models: median Rho 0.80 (range 0.58-0.95 and 0.90 (range 0.78-0.95, respectively. A strong correlation was found between TAM and the results of sound spectrum analysis; in the embolization model the median r was 0.91 (range 0.88-0.97 for MAXpeak and 0.91 (range 0.82-0.98 for MAXpeak-15 dB. In the anemia model, the corresponding values were 0.92 (range 0.78-0.96 and 0.96 (range 0.89-0.98, respectively. CONCLUSION: Audio-spectrum analysis reflects the subjective perception of Doppler sound signals in the umbilical artery and has a strong correlation to TAM-velocity. This information might be of importance for clinical management of complicated pregnancies as an addition to conventional Doppler parameters.

  15. Normal Doppler velocimetry of renal vasculature in Persian cats.

    Science.gov (United States)

    Carvalho, Cibele F; Chammas, Maria C

    2011-06-01

    Renal diseases are common in older cats. Decreased renal blood flow may be the first sign of dysfunction and can be evaluated by Doppler ultrasound. But previous studies suggest that the resistive index (RI) has a low sensitivity for detecting renal disease. Doppler waveforms of renal and intrarenal arteries demonstrate decreased blood flow before there are any changes in the RI. The purpose of this study was to evaluate the normal Doppler flowmetrics parameters of renal arteries (RAs), interlobar arteries (IAs) and abdominal aorta (AO) in adult healthy, Persian cats. Twenty-five Persian cats (13 females and 12 males with mean age of 30 months and an age range 12-60 months) with normal clinical examinations and biochemical tests and normal systemic blood pressure were given B-mode ultrasonographies in order to exclude all nephropathies, including polycystic kidney disease. All measurements were performed on both kidneys. Both kidneys (n=50) were examined by color mapping of the renal vasculature. Pulsed Doppler was used to examine both RAs, the IAs at cranial, middle and caudal sites, and the AO. The RI was calculated for all of the vessels. Early systolic acceleration (ESA) of RA and IA was obtained with Doppler spectral analysis. Furthermore, the ratio indices between RA/AO, and IA/RA velocities were calculated. The mean values of peak systolic velocity (PSV) and the diameter for AO were 53.17±13.46 cm/s and 0.38±0.08 cm, respectively. The mean RA diameter for all 50 kidneys was 0.15±0.02 cm. Considering the velocimetric values in both RAs, the mean PSV and RI that were obtained were 41.17±9.40 cm/s and 0.54±0.07. The RA had a mean ESA of 1.12±1.14 m/s(2) and the calculated upper limit of the reference value was 3.40 m/s(2). The mean renal-aortic ratio was 0.828±0.296. The IA showed PSV and RI values of 32.16±9.33 cm/s and 0.52±0.06, respectively. The mean ESA of all IAs was 0.73±0.61 m/s(2). The calculated upper limit of the reference value was 2.0m

  16. Evaluation of structural vacancies for 1/1-Al-Re-Si approximant crystals by positron annihilation spectroscopy

    Science.gov (United States)

    Yamada, K.; Suzuki, H.; Kitahata, H.; Matsushita, Y.; Nozawa, K.; Komori, F.; Yu, R. S.; Kobayashi, Y.; Ohdaira, T.; Oshima, N.; Suzuki, R.; Takagiwa, Y.; Kimura, K.; Kanazawa, I.

    2018-01-01

    The size of structural vacancies and structural vacancy density of 1/1-Al-Re-Si approximant crystals with different Re compositions were evaluated by positron annihilation lifetime and Doppler broadening measurements. Incident positrons were found to be trapped at the monovacancy-size open space surrounded by Al atoms. From a previous analysis using the maximum entropy method and Rietveld method, such an open space is shown to correspond to the centre of Al icosahedral clusters, which locates at the vertex and body centre. The structural vacancy density of non-metallic Al73Re17Si10 was larger than that of metallic Al73Re15Si12. The observed difference in the structural vacancy density reflects that in bonding nature and may explain that in the physical properties of the two samples.

  17. Levels of 31P from [alpha]-particle capture in 27Al

    NARCIS (Netherlands)

    Voigt, M.J.A. de; Regenboog, D.A.; Grootenhuis, J.; Leun, C. van der

    1971-01-01

    Resonance energies, strengths and decay schemes have been determined for seventeen 27Al(α, γ)31P resonances in the range Eα = 2.3–3.3 MeV. New levels of 31P are reported at Ex = 6503±3, 6792±3, 7117.7±1.0, 7441.4±1.0 and 8345.5±1.5 keV. The reaction Q-value is found as 9665.1 ±1.3 keV. Doppler-shift

  18. Low-frequency high-definition power Doppler in visualizing and defining fetal pulmonary venous connections.

    Science.gov (United States)

    Liu, Lin; He, Yihua; Li, Zhian; Gu, Xiaoyan; Zhang, Ye; Zhang, Lianzhong

    2014-07-01

    The use of low-frequency high-definition power Doppler in assessing and defining pulmonary venous connections was investigated. Study A included 260 fetuses at gestational ages ranging from 18 to 36 weeks. Pulmonary veins were assessed by performing two-dimensional B-mode imaging, color Doppler flow imaging (CDFI), and low-frequency high-definition power Doppler. A score of 1 was assigned if one pulmonary vein was visualized, 2 if two pulmonary veins were visualized, 3 if three pulmonary veins were visualized, and 4 if four pulmonary veins were visualized. The detection rate between Exam-1 and Exam-2 (intra-observer variability) and between Exam-1 and Exam-3 (inter-observer variability) was compared. In study B, five cases with abnormal pulmonary venous connection were diagnosed and compared to their anatomical examination. In study A, there was a significant difference between CDFI and low-frequency high-definition power Doppler for the four pulmonary veins observed (P low-frequency high-definition power Doppler was higher than that when employing two-dimensional B-mode imaging or CDFI. There was no significant difference between the intra- and inter-observer variabilities using low-frequency high-definition power Doppler display of pulmonary veins (P > 0.05). The coefficient correlation between Exam-1 and Exam-2 was 0.844, and the coefficient correlation between Exam-1 and Exam-3 was 0.821. In study B, one case of total anomalous pulmonary venous return and four cases of partial anomalous pulmonary venous return were diagnosed by low-frequency high-definition power Doppler and confirmed by autopsy. The assessment of pulmonary venous connections by low-frequency high-definition power Doppler is advantageous. Pulmonary venous anatomy can and should be monitored during fetal heart examination.

  19. Glare Spot Phase Doppler Anemometry

    Science.gov (United States)

    Hespel, Camille; Ren, Kuanfang; Gréhan, Gérard; Onofri, Fabrice

    2007-06-01

    The Phase Doppler anemometry has been developed to measure simultaneously the velocity and the size of droplets. The measurement of the refractive index would be also interesting since it depends on the temperature and the composition of the particle and its measurement permits both to increase the quality of the diameter measurement and to obtain information on the temperature and/or the composition of the droplets. In this paper, we introduce a Glare Spot Phase Doppler Anemometry which uses two large beams. In this case, the images of the particle formed by the reflected and refracted light, known as glare spots, are separated in space. When a particle passes in the probe volume, the two parts in a signal obtained by a detector in forward direction are then separated in time. If two detectors are used the phase differences between two signals, the distance and the intensity ratio of reflected and refracted parts can be obtained and they provide rich information about the particle diameter and its refractive index, as well as its velocity. This paper is devoted to the numerical study of such a configuration with two theoretical models: geometrical optics and rigorous electromagnetism solution.

  20. Influence of thin porous Al2O3 layer on aluminum cathode to the Hα line shape in glow discharge

    International Nuclear Information System (INIS)

    Steflekova, V.; Sisovic, N. M.; Konjevic, N.

    2009-01-01

    The results of the Balmer alfa line shape study in a plane cathode-hollow anode Grimm discharge with aluminum (Al) cathode covered with thin layer of porous Al 2 O 3 are presented. The comparison with same line profile recorded with pure Al cathode shows lack of excessive Doppler broadened line wings, which are always detected in glow discharge with metal cathode. The effect is explained by the lack of strong electric field in the cathode sheath region, which is missing in the presence of thin oxide layer in, so called, spray discharge.

  1. Two-dimensional intraventricular flow mapping by digital processing conventional color-Doppler echocardiography images.

    Science.gov (United States)

    Garcia, Damien; Del Alamo, Juan C; Tanne, David; Yotti, Raquel; Cortina, Cristina; Bertrand, Eric; Antoranz, José Carlos; Perez-David, Esther; Rieu, Régis; Fernandez-Aviles, Francisco; Bermejo, Javier

    2010-10-01

    Doppler echocardiography remains the most extended clinical modality for the evaluation of left ventricular (LV) function. Current Doppler ultrasound methods, however, are limited to the representation of a single flow velocity component. We thus developed a novel technique to construct 2D time-resolved (2D+t) LV velocity fields from conventional transthoracic clinical acquisitions. Combining color-Doppler velocities with LV wall positions, the cross-beam blood velocities were calculated using the continuity equation under a planar flow assumption. To validate the algorithm, 2D Doppler flow mapping and laser particle image velocimetry (PIV) measurements were carried out in an atrio-ventricular duplicator. Phase-contrast magnetic resonance (MR) acquisitions were used to measure in vivo the error due to the 2D flow assumption and to potential scan-plane misalignment. Finally, the applicability of the Doppler technique was tested in the clinical setting. In vitro experiments demonstrated that the new method yields an accurate quantitative description of the main vortex that forms during the cardiac cycle (mean error for vortex radius, position and circulation). MR image analysis evidenced that the error due to the planar flow assumption is close to 15% and does not preclude the characterization of major vortex properties neither in the normal nor in the dilated LV. These results are yet to be confirmed by a head-to-head clinical validation study. Clinical Doppler studies showed that the method is readily applicable and that a single large anterograde vortex develops in the healthy ventricle while supplementary retrograde swirling structures may appear in the diseased heart. The proposed echocardiographic method based on the continuity equation is fast, clinically-compliant and does not require complex training. This technique will potentially enable investigators to study of additional quantitative aspects of intraventricular flow dynamics in the clinical setting by

  2. Brazilian Guidelines for transcranial doppler in children and adolescents with sickle cell disease

    Directory of Open Access Journals (Sweden)

    Clarisse Lopes de Castro Lobo

    2011-02-01

    Full Text Available BACKGROUND: Sickle cell disease is the most common monogenic hereditary disease in Brazil. Although strokes are one of the main causes of morbidity and mortality in these patients, the use of transcranial Doppler to identify children at risk is not universally used. OBJECTIVE: To develop Brazilian guidelines for the use of transcranial Doppler in sickle cell disease children and adolescents, so that related health policies can be expanded, and thus contribute to reduce morbidity and mortality. METHODS: The guidelines were formulated in a consensus meeting of experts in transcranial Doppler and sickle cell disease. The issues discussed were previously formulated and scientific articles in databases (MEDLINE, SciELO and Cochrane were carefully analyzed. The consensus for each question was obtained by a vote of experts on the specific theme. RESULTS: Recommendations were made, including indications for the use of transcranial Doppler according to the sickle cell disease genotype and patients age; the necessary conditions to perform the exam and its periodicity depending on exam results; the criteria for the indication of blood transfusions and iron chelation therapy; the indication of hydroxyurea; and the therapeutic approach in cases of conditional transcranial Doppler. CONCLUSION: The Brazilian guidelines on the use of transcranial doppler in sickle cell disease patients may reduce the risk of strokes, and thus reduce the morbidity and mortality and improve the quality of life of sickle cell disease patients.

  3. Evaluation of factors influencing arterial Doppler waveforms in an in vitro flow phantom

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Chang Kyu [Dept. of Radiology, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, Seoul (Korea, Republic of); Lee, Kyoung Ho [Dept. of Radiology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam (Korea, Republic of); Kim, Seung Hyup [Dept. of Radiology and the Institute of Radiation Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2017-01-15

    The aim of this study was to investigate factors that influence arterial Doppler waveforms in an in vitro phantom to provide a more accurate and comprehensive explanation of the Doppler signal. A flow model was created using a pulsatile artificial heart, rubber or polyethylene tubes, a water tank, and a glass tube. Spectral Doppler tracings were obtained in multiple combinations of compliance, resistance, and pulse rate. Peak systolic velocity, minimum diastolic velocity, resistive index (RI), pulsatility index, early systolic acceleration time, and acceleration index were measured. On the basis of these measurements, the influences of the variables on the Doppler waveforms were analyzed. With increasing distal resistance, the RI increased in a relatively linear relationship. With increasing proximal resistance, the RI decreased. The pulsus tardus and parvus phenomenon was observed with a small acceleration index in the model with a higher grade of stenosis. An increase in the distal resistance masked the pulsus tardus and parvus phenomenon by increasing the acceleration index. Although this phenomenon occurred independently of compliance, changes in the compliance of proximal or distal tubes caused significant changes in the Doppler waveform. There was a reverse relationship between the RI and the pulse rate. Resistance and compliance can alter the Doppler waveforms independently. The pulse rate is an extrinsic factor that also influences the RI. The compliance and distal resistance, as well as proximal resistance, influence the pulsus tardus and parvus phenomenon.

  4. Ophthalmic artery color Doppler ultrasonography in mild-to-moderate preeclampsia

    International Nuclear Information System (INIS)

    Ayaz, Tunahan; Akansel, Gur.; Hayirlioglu, Alper; Arslan, Arzu; Suer, Necdet; Kuru, Ihsan

    2003-01-01

    Objective: To evaluate the hemodynamic changes in mild-moderate preeclampsia using ophthalmic artery Doppler ultrasonography technique. Methods: Ophthalmic artery pulsatility and resistivity indices were calculated in 30 mild-moderate preeclamptic women and 30 normotensive gravid women of matched gestational age. Student's t-test was performed to test the significance of difference. Results: Both indices of peripheral resistance were found to be significantly lower in the ophthalmic arteries of mild-moderately preeclamptic women than those measured in normotensive gravid women at similar stage of pregnancy. In a small number patients whose disease progressed to severe preeclampsia, both indices increased. Conclusion: In patients with mild-moderate preeclampsia, ophthalmic artery color Doppler ultrasonography detects hemodynamic changes that are not present in normotensive gravid women. Reversal of Doppler patterns in a small number of patients with progressive disease supports the hypotheses suggesting the presence of early vasodilation and late vasospasm in the etiology of preeclampsia

  5. 3D atom microscopy in the presence of Doppler shift

    Science.gov (United States)

    Rahmatullah; Chuang, You-Lin; Lee, Ray-Kuang; Qamar, Sajid

    2018-03-01

    The interaction of hot atoms with laser fields produces a Doppler shift, which can severely affect the precise spatial measurement of an atom. We suggest an experimentally realizable scheme to address this issue in the three-dimensional position measurement of a single atom in vapors of rubidium atoms. A three-level Λ-type atom-field configuration is considered where a moving atom interacts with three orthogonal standing-wave laser fields and spatial information of the atom in 3D space is obtained via an upper-level population using a weak probe laser field. The atom moves with velocity v along the probe laser field, and due to the Doppler broadening the precision of the spatial information deteriorates significantly. It is found that via a microwave field, precision in the position measurement of a single hot rubidium atom can be attained, overcoming the limitation posed by the Doppler shift.

  6. Airborne Doppler Wind Lidar Post Data Processing Software DAPS-LV

    Science.gov (United States)

    Beyon, Jeffrey Y. (Inventor); Koch, Grady J. (Inventor); Kavaya, Michael J. (Inventor)

    2015-01-01

    Systems, methods, and devices of the present invention enable post processing of airborne Doppler wind LIDAR data. In an embodiment, airborne Doppler wind LIDAR data software written in LabVIEW may be provided and may run two versions of different airborne wind profiling algorithms. A first algorithm may be the Airborne Wind Profiling Algorithm for Doppler Wind LIDAR ("APOLO") using airborne wind LIDAR data from two orthogonal directions to estimate wind parameters, and a second algorithm may be a five direction based method using pseudo inverse functions to estimate wind parameters. The various embodiments may enable wind profiles to be compared using different algorithms, may enable wind profile data for long haul color displays to be generated, may display long haul color displays, and/or may enable archiving of data at user-selectable altitudes over a long observation period for data distribution and population.

  7. [The use of intraoperative Doppler ultrasound in endoscopic transsphenoidal surgery].

    Science.gov (United States)

    Sharipov, O I; Kutin, M A; Kalinin, P L; Fomichev, D V; Lukshin, V A; Kurnosov, A B

    2016-01-01

    Doppler ultrasound (DUS) has been widely used in neurosurgical practice to diagnose various cerebrovascular diseases. This technique is used in transsphenoidal surgery to identify the localization of intracranial arteries when making an approach or during tumor resection. To identify the cavernous segment of the internal carotid artery (ICA) and/or basilar artery during endoscopic transsphenoidal surgery, we used a combined device on the basis of a click line curette («Karl Storz») and a 16 MHz Doppler probe (Lassamed). The technique was used in 51 patients during both standard transsphenoidal surgery (23 cases) and transsphenoidal tumor resection through an extended approach (28 cases). Doppler ultrasound was used in different situations: to determine a trajectory of the endonasal transsphenoidal approach in the absence of the normal anatomical landmarks (16 cases), to define the limits of safe resection of a tumor located in the laterosellar region (7), and to implement an extended transsphenoidal endoscopic approach (28). Intraoperative Doppler ultrasound enabled identification of the cavernous segment of the internal carotid artery in 45 cases and the basilar artery in 2 cases; a blood vessel was not found in 4 cases. Injury to the cavernous segment of the internal carotid artery was observed only in 1 case. The use of the described combined device in transsphenoidal surgery turned Doppler ultrasound into an important and useful technique for visualization of the ICA within the tumor stroma as well as in the case of the changed skull base anatomy. Its use facilitates manipulations in a deep and narrow wound and enables inspection of the entire surface of the operative field in various planes, thereby surgery becomes safer due to the possibility of maximum investigation of the operative field.

  8. Tissue doppler echocardiography for evaluating left ventricular functions in obese

    Directory of Open Access Journals (Sweden)

    Mecnun Çetin

    2013-03-01

    Full Text Available Objective: The aim of this study was to investigate theimpact of childhood obesity on ventricular functions usingtissue Doppler echocardiography.Materials and methods: The mitral tissue Doppler signalswere recorded in the apical four-chamber view, with thesample volume placed at the lateral walls of mitral annulus.The mitral flow was examined with the sample Pulse Dopplerpositioned parallely to flow just at the orifice of the mitralleaflets. Twenty obese (mean age, 161.5±25.8 monthsand 20 healthy children (mean age, 151.2±33.5 monthswere included to this study.Results: Body mass index (BMI was significantly higherin obese group (30.92±6.87. Isovolumic relaxation time(IVRT which is one of the left ventricular (LV diastolicfunction parameters was 66.10±7.30 ms in obese group,and 58.70±9.06 ms in the control group. IVRT was significantlyhigher in the obese group (p=0.007. In obesegroup, the mitral annulus tissue Doppler E velocity wasdecreased, flow velocity was increased and decrement inEm/Am ratio was significant. We found significant negativecorrelation between BMI and LV Em/Am ratio. Myocardialperformance index (MPI in obese group and control groupwas 0.50±0.07 and 0.41±0.04, respectively (p<0.001.Between MPI and LV Em/Am ratio there was a significantnegative correlation while MPI showed positive correlationwith BMI. In obese group septal and LV posterior wall thicknesswas shown to be significantly increased compared tothe control group (p<0.001.Conclusion: Our findings, may be important for determinationof the relationship between obesity and cardiovascularrisk factors in children. Tissue Doppler echocardiographicimaging may be useful in revealing this relationship.Key words: obesity, doppler echocardiography, ventricular dysfunction

  9. The Role of Color Doppler Ultrasonography in Characterization of Thyroid Tumors

    International Nuclear Information System (INIS)

    Kim, Hee Soo; Jeon, Pyong; Won, Jong Yoon; Na, Jae Beom; Lee, Hyang Mee; Yoo, Hyung Sik; Lee, Jong Tae; Park, Jeong Soo; Cho, Nam Hoon

    1995-01-01

    To assess the usefulness of color Doppler ultrasonography in the characterization of thyroid tumors, surgically proven 88 nodules in 85 patients were evaluated. Using 10 MHz linear array transducer, gray scale images were initially evaluated. Then, distribution pattern of color signals (marginal, intra-tumoral, mixed) and graded internal vascularity according to morphology of color signal (0:absence of internal signal, 1: spotty, 2: linear,3: branching) were observed on color doppler imaging. Pulsed doppler waves were analyzed with parameters including peak systolic velocity(PSV), resistive index(RI), and pulsatile index(PI). Significantly larger numbers of intra-tumoral type, 20 cases(62.5%), were observed in malignant nodules, whereas mixed forms were predominant in benign group, 37 cases (66%) In graded internal vascularity, malignant nodules tended to have grade 2 or 3 signals, whereas benign nodules tended to have grade 0 or 1 signals. Spectral wave analysis show no significant difference in the value of PSV, RI, and PI between malignancy and benignity group. In conclusion, color Doppler imaging has a potential role in the characterization of thyroid nodules as a supportive method for gray scale diagnosis

  10. Noticeable positive Doppler effect on optical bistability in an N-type active Raman gain atomic system

    International Nuclear Information System (INIS)

    Chang Zeng-Guang; Zhang Jing-Tao; Niu Yue-Ping; Gong Shang-Qing

    2012-01-01

    We theoretically investigate the Doppler effect on optical bistability in an N-type active Raman gain atomic system inside an optical ring cavity. It is shown that the Doppler effect can greatly enhance the dispersion and thus create the bistable behaviour or greatly increase the bistable region, which has been known as the positive Doppler effect on optical bistability. In addition, we find that a positive Doppler effect can change optical bistability from the hybrid dispersion-gain type to a dispersive type

  11. Current Perspectives in Hyperbaric Physiology, Ultrasonic Doppler Bubble Detection, and Mass Spectrometry,

    Science.gov (United States)

    1979-12-28

    Doppler sound made by a bubble passing through the inson- ified volume blood vessel resembles a very sharp truncated whistle , chirp or click depending...the Doppler ultrasound , suffered the "slings and arrows of outrageous criticism" to borrow and beat a phrase. It is not appropriate to go into this

  12. Aircraft Wake Vortex Measurement with Coherent Doppler Lidar

    Directory of Open Access Journals (Sweden)

    Wu Songhua

    2016-01-01

    Full Text Available Aircraft vortices are generated by the lift-producing surfaces of the aircraft. The variability of near-surface conditions can change the drop rate and cause the cell of the wake vortex to twist and contort unpredictably. The pulsed Coherent Doppler Lidar Detection and Ranging is an indispensable access to real aircraft vortices behavior which transmitting a laser beam and detecting the radiation backscattered by atmospheric aerosol particles. Experiments for Coherent Doppler Lidar measurement of aircraft wake vortices has been successfully carried out at the Beijing Capital International Airport (BCIA. In this paper, the authors discuss the Lidar system, the observation modes carried out in the measurements at BCIA and the characteristics of vortices.

  13. ANALISIS EFEK KECELAKAAN WATER INGRESS TERHADAP REAKTIVITAS DOPPLER TERAS RGTT200K

    Directory of Open Access Journals (Sweden)

    Zuhair Zuhair

    2015-03-01

    Full Text Available Dalam high temperature reactor, koefisien reaktivitas temperatur yang didesain negatif menjamin reaksi fisi dalam teras tetap berada di bawah kendali dan panas peluruhan tidak akan pernah melelehkan bahan bakar yang menyebabkan terlepasnya zat radioaktif ke lingkungan. Namun masuknya air (water ingress ke dalam teras reaktor akibat pecahnya tabung penukar panas generator uap, yang dikenal sebagai salah satu kecelakaan dasar desain, dapat mengintroduksi reaktivitas positif dengan potensi bahaya lainnya seperti korosi grafit dan kerusakan material struktur reflektor. Makalah ini akan menganalisis efek kecelakaan water ingress terhadap reaktivitas Doppler teras RGTT200K. Kapabilitas koefisien reaktivitas Doppler untuk mengkompensasi reaktivitas positif yang timbul selama kecelakaan water ingress akan diuji melalui serangkaian perhitungan dengan program MCNPX dan pustaka ENDF/B-VII untuk perubahan temperatur bahan bakar dari 800K hingga 1800K. Tiga opsi kernel bahan bakar UO2, ThO2/UO2 dan PuO2 dengan tiga model kisi bahan bakar pebble di teras reaktor diterapkan untuk kondisi water ingress dengan densitas air dari 0 hingga 1.000 kg/m3. Hasil perhitungan memperlihatkan koefisien reaktivitas Doppler tetap negatif untuk seluruh opsi bahan bakar yang dipertimbangkan bahkan untuk posibilitas water ingress yang besar. Efek water ingress lebih kuat pada model kisi dengan fraksi packing lebih rendah karena lebih banyak volume yang tersedia untuk air yang memasuki teras reaktor. Efek water ingress juga lebih kuat di teras uranium dibandingkan teras thorium dan plutonium sebagai konsekuensi dari fenomena Doppler dimana absorpsi neutron di daerah resonansi 238U lebih besar daripada 232Th dan 240Pu. Secara keseluruhan dapat disimpulkan bahwa, koefisien Doppler teras RGTT200K mampu mengkompensasi insersi reaktivitas yang diintroduksi oleh kecelakaan water ingress. Teras RGTT200K dengan bahan bakar UO2, ThO2/UO2 dan PuO2 dapat mempertahankan fitur keselamatan

  14. 3D power Doppler ultrasound in early diagnosis of preeclampsia.

    Science.gov (United States)

    Neto, R Moreira; Ramos, J G L

    2016-01-01

    Preeclampsia is a known cause of maternal, fetal and neonatal morbidity and mortality. Thus, evaluation of the predicting value of comparing 3D power Doppler indices (3DPD) of uteroplacental circulation (UPC) in the first and second trimester in patients who developed preeclampsia (PE) and those who did not and testing the hypothesis that the parameters of vascularization and placenta flow intensity, as determined by three-dimensional ultrasound (3D), are different in normal pregnancies compared with preeclampsia, could be a suitable screening method. A prospective observational study using 3D power Doppler were performed to evaluate the placental perfusion in 96 pregnant women who came to do the ultrasound routine between 11 and 14 weeks. The placental vascular index (VI), flow index (FI), blood vessels and blood flow index (VFI) by three-dimensional Doppler histogram were calculated. All patients repeated the exam between 16 and 20 weeks. The outcome was scored as normal or preeclamptic. Placental vascular indices including VI, FI and VFI were significantly lower in preeclamptic placentas compared with controls in the study performed in the second trimester (ppower Doppler assessment of placental vascular indices in the second trimester has the potential to detect women at risk for subsequent development of PE. Copyright © 2015 International Society for the Study of Hypertension in Pregnancy. Published by Elsevier B.V. All rights reserved.

  15. Gestational trophoblastic neoplasia: efficacy of color doppler ultrasound

    International Nuclear Information System (INIS)

    Song, Sun Wha; Jee, Won Hee; Choe, Bo Young; Byun, Jae Young; Choi, Byung Gil; Shinn, Kyung Sub

    1997-01-01

    To evaluate the efficacy of color Doppler ultrasound (US) in the diagnosis of gestational trophoblastic neoplasia (GTN). Intralesional color flows and resistive index (RI) on color Doppler US were prospectively analyzed in 21 consecutive suspected GTN cases. RI of the intralesional artery was investigated on the basis of the presence or absence of mass and metastasis. Correlation between RI of intralesional artery and urinary β-hCG was also investigated. Intralesional color flows were identified in 15 patients with GTN. On operation, intralesional color flows were observed in one of two patients in whom the presence of completely necrotic tissue was confirmed. Intralesional color flows, however, were not detected in four patients who were proved not to be GTN sufferers. Sensitivity, specificity, accuracy, positive and negative predictive values, and accuracy were 100%, 83%, 95%, 94% and 100%, respectively. Significant correlation between RI of the intralesional artery and urinary β-hCG was not established (p=0.49, r=0.19). RI of this artery was not substantially different between groups with and without mass, and between groups with and without metastasis (p=0.32, p=0.82). The current study demonstrates that color Doppler US is a sensitive and useful method for the diagnosis of GTN

  16. An intercomparison of methods for solving the stochastic collection equation with a focus on cloud radar Doppler spectra in drizzling stratocumulus

    Science.gov (United States)

    Lee, H.; Fridlind, A. M.; Ackerman, A. S.; Kollias, P.

    2017-12-01

    Cloud radar Doppler spectra provide rich information for evaluating the fidelity of particle size distributions from cloud models. The intrinsic simplifications of bulk microphysics schemes generally preclude the generation of plausible Doppler spectra, unlike bin microphysics schemes, which develop particle size distributions more organically at substantial computational expense. However, bin microphysics schemes face the difficulty of numerical diffusion leading to overly rapid large drop formation, particularly while solving the stochastic collection equation (SCE). Because such numerical diffusion can cause an even greater overestimation of radar reflectivity, an accurate method for solving the SCE is essential for bin microphysics schemes to accurately simulate Doppler spectra. While several methods have been proposed to solve the SCE, here we examine those of Berry and Reinhardt (1974, BR74), Jacobson et al. (1994, J94), and Bott (2000, B00). Using a simple box model to simulate drop size distribution evolution during precipitation formation with a realistic kernel, it is shown that each method yields a converged solution as the resolution of the drop size grid increases. However, the BR74 and B00 methods yield nearly identical size distributions in time, whereas the J94 method produces consistently larger drops throughout the simulation. In contrast to an earlier study, the performance of the B00 method is found to be satisfactory; it converges at relatively low resolution and long time steps, and its computational efficiency is the best among the three methods considered here. Finally, a series of idealized stratocumulus large-eddy simulations are performed using the J94 and B00 methods. The reflectivity size distributions and Doppler spectra obtained from the different SCE solution methods are presented and compared with observations.

  17. Transcranial Doppler sonography in familial hemiplegic migraine

    International Nuclear Information System (INIS)

    Pierelli, F.; Pauri, F.; Cupini, L.M.; Fiermonte, G.; Rizzo, P.A.

    1991-01-01

    A patient affected by familial hemiplegic migraine underwent transcranial Doppler sonography twice: the first during a spontaneous attack with right hemiparesis and aphasia, the second during a headachefree period. During the attack the following haemodynamic changes were seen: (a) bilateral increase in the middle cerebral artery and anterior cerebral artery blood flow velocities (this increase was more pronounced on the left side), (b) decreased systo-diastolic ratio and pulsatility index on the right side, (c) increased systo-diastolic ratio and pulsatility index on the left side. The results indicate that during the attack in this familial hemiplegic migraine patient, a diffuse vasoconstriction of the basal cerebral arteries developed. Moreover, transcranial Doppler sonography data suggest that a prolonged vasoconstriction of the peripheral arterioles could play a role in determining the neurological symptoms in this syndrome. 13 refs., 1 figs., 1 tab

  18. Transcranial Doppler sonography in familial hemiplegic migraine

    Energy Technology Data Exchange (ETDEWEB)

    Pierelli, F.; Pauri, F.; Cupini, L.M.; Fiermonte, G.; Rizzo, P.A. (Universita la Sapienza, Roma (Italy))

    1991-02-01

    A patient affected by familial hemiplegic migraine underwent transcranial Doppler sonography twice: the first during a spontaneous attack with right hemiparesis and aphasia, the second during a headachefree period. During the attack the following haemodynamic changes were seen: (a) bilateral increase in the middle cerebral artery and anterior cerebral artery blood flow velocities (this increase was more pronounced on the left side), (b) decreased systo-diastolic ratio and pulsatility index on the right side, (c) increased systo-diastolic ratio and pulsatility index on the left side. The results indicate that during the attack in this familial hemiplegic migraine patient, a diffuse vasoconstriction of the basal cerebral arteries developed. Moreover, transcranial Doppler sonography data suggest that a prolonged vasoconstriction of the peripheral arterioles could play a role in determining the neurological symptoms in this syndrome. 13 refs., 1 figs., 1 tab.

  19. Void effects on BWR Doppler and void reactivity feedback

    International Nuclear Information System (INIS)

    Hsiang-Shou Cheng; Diamond, D.J.

    1978-01-01

    The significance of steam voids and control rods on the Doppler feedback in a gadolinia shimmed BWR is demonstrated. The importance of bypass voids when determining void feedback is also shown. Calculations were done using a point model, i.e., feedback was expressed in terms of reactivity coefficients which were determined for individual four-bundle configurations and then appropriately combined to yield reactor results. For overpower transients the inclusion of the void effect of control rods is to reduce Doppler feedback. For overpressurization transients the inclusion of the effect of bypass void wil increase the reactivity due to void collapse. (author)

  20. Sub-Doppler cooling in reduced-period optical lattice geometries

    International Nuclear Information System (INIS)

    Berman, P.R.; Raithel, G.; Zhang, R.; Malinovsky, V.S.

    2005-01-01

    It is shown that sub-Doppler cooling occurs in an atom-field geometry that can lead to reduced-period optical lattices. Four optical fields are combined to produce a 'standing wave' Raman field that drives transitions between two ground state sublevels. In contrast to conventional Sisyphus cooling, sub-Doppler cooling to zero velocity occurs when all fields are polarized in the same direction. Solutions are obtained using both semiclassical and quantum Monte Carlo methods in the case of exact two-photon resonance. The connection of the results with conventional Sisyphus cooling is established using a dressed state basis

  1. Positron life time and annihilation Doppler broadening measurements on transition metal complexes

    International Nuclear Information System (INIS)

    Levay, B.; Burger, K.

    1982-01-01

    Positron life time and annihilation Doppler broadening measurements have been carried out on 44 solid coordination compounds. Several correlations have been found between the annihilation life time (tau 1 ) and line shape parameters (L) and the chemical structure of the compounds. Halide ligands were the most active towards positrons. This fact supports the assumption on the possible formation of [e + X - ] positron-halide bound state. The life time was decreasing and the annihilation energy spectra were broadening with the increasing negative character of the halides. The aromatic base ligands affected the positron-halide interaction according to their basicity and space requirement and thus they indirectly affected the annihilation parameters, too. In the planar and tetrahedral complexes the electron density on the central met--al ion affected directly the annihilation parameters, while in the octahedral mixed complexes it had only an ind--irect effect through the polarization of the halide ligands. (author)

  2. Collapse and revival of the Doppler-Rabi oscillations of a moving atom in a cavity

    International Nuclear Information System (INIS)

    Kozlovskii, A. V.

    2008-01-01

    Collapse and revival of the Doppler-Rabi oscillations of a two-level atom moving in a cavity electromagnetic field are analyzed. The coupled atom-field dynamics are predicted accurately by numerical calculation and approximately by using the stationary phase approximation combined with the Poisson summation formula. The collapse and revival patterns are shown to be qualitatively different in the cases of moving atom and atom at rest. In particular, quantum revivals of Doppler-Rabi oscillations occur with a period determined by the Doppler shift of the atomic transition frequency. This regime of Doppler-Rabi oscillations requires that the Rabi frequency and the Doppler shift satisfy the condition Ω R D . Under the inverse relation, the collapse- revival phenomenon generally does not occur. It is shown that even a small amount of atom-cavity detuning eliminates collapse-revival behavior. The analysis is performed for both coherent and thermal cavity fields

  3. The Assessment of Left Ventricular Time-Varying Radius Using Tissue Doppler Imaging

    Directory of Open Access Journals (Sweden)

    Fardin Mirbolouk

    2012-03-01

    Full Text Available Background: Left ventricular twist/torsion is believed to be a sensitive indicator of systolic and diastolic performance. To obtain circumferential rotation using tissue Doppler imaging, we need to estimate the time-varying radius of the left ventricle throughout the cardiac cycle to convert the tangential velocity into angular velocity. Objectives: The aim of this study was to investigate accuracy of measured LV radius using tissue Doppler imaging throughout the cardiac cycle compared to two-dimensional (2D imaging. Methods: A total of 35 subjects (47±12 years old underwent transthoracic echocardiographic standard examinations. Left ventricular radius during complete cardiac cycle measured using tissue Doppler and 2D-imaging at basal and apical short axis levels. For this reason, the 2D-images and velocity-time data derived and transferred to a personal computer for off-line analysis. 2D image frames analyzed via a program written in the MATLAB software. Velocity-time data from anteroseptal at basal level (or anterior wall at apical level and posterior walls transferred to a spreadsheet Excel program for the radius calculations. Linear correlation and Bland-Altman analysis were calculated to assess the relationships and agreements between the tissue Doppler and 2D-measured radii throughout the cardiac cycle. Results: There was significant correlation between tissue Doppler and 2D-measured radii and the Pearson correlation coefficients were 0.84 to 0.97 (P<0.05. Bland-Altman analysis by constructing the 95% limits of agreement showed that the good agreements existed between the two methods. Conclusion: It can be concluded from our experience that the tissue Doppler imaging can reasonably estimate radius of the left ventricle throughout the cardiac cycle.

  4. A Doppler Radar System for Sensing Physiological Parameters in Walking and Standing Positions

    Directory of Open Access Journals (Sweden)

    Malikeh Pour Ebrahim

    2017-03-01

    Full Text Available Doppler radar can be implemented for sensing physiological parameters wirelessly at a distance. Detecting respiration rate, an important human body parameter, is essential in a range of applications like emergency and military healthcare environments, and Doppler radar records actual chest motion. One challenge in using Doppler radar is being able to monitor several patients simultaneously and in different situations like standing, walking, or lying. This paper presents a complete transmitter-receiver Doppler radar system, which uses a 4 GHz continuous wave radar signal transmission and receiving system, to extract base-band data from a phase-shifted signal. This work reports experimental evaluations of the system for one and two subjects in various standing and walking positions. It provides a detailed signal analysis of various breathing rates of these two subjects simultaneously. These results will be useful in future medical monitoring applications.

  5. Ophthalmic artery color Doppler ultrasonography in mild-to-moderate preeclampsia

    Energy Technology Data Exchange (ETDEWEB)

    Ayaz, Tunahan; Akansel, Gur. E-mail: gakansel@superonline.com; Hayirlioglu, Alper; Arslan, Arzu; Suer, Necdet; Kuru, Ihsan

    2003-06-01

    Objective: To evaluate the hemodynamic changes in mild-moderate preeclampsia using ophthalmic artery Doppler ultrasonography technique. Methods: Ophthalmic artery pulsatility and resistivity indices were calculated in 30 mild-moderate preeclamptic women and 30 normotensive gravid women of matched gestational age. Student's t-test was performed to test the significance of difference. Results: Both indices of peripheral resistance were found to be significantly lower in the ophthalmic arteries of mild-moderately preeclamptic women than those measured in normotensive gravid women at similar stage of pregnancy. In a small number patients whose disease progressed to severe preeclampsia, both indices increased. Conclusion: In patients with mild-moderate preeclampsia, ophthalmic artery color Doppler ultrasonography detects hemodynamic changes that are not present in normotensive gravid women. Reversal of Doppler patterns in a small number of patients with progressive disease supports the hypotheses suggesting the presence of early vasodilation and late vasospasm in the etiology of preeclampsia.

  6. Doppler Wind Lidar Measurements and Scalability to Space

    Data.gov (United States)

    National Aeronautics and Space Administration — Global measurements of wind speed and direction from Doppler wind lidars, if available, would significantly improve forecasting of severe weather events such as...

  7. Laser Doppler flowmetry for measurement of laminar capillary blood flow in the horse

    Science.gov (United States)

    Adair, Henry S., III

    1998-07-01

    Current methods for in vivo evaluation of digital hemodynamics in the horse include angiography, scintigraphy, Doppler ultrasound, electromagnetic flow and isolated extracorporeal pump perfused digit preparations. These techniques are either non-quantifiable, do not allow for continuous measurement, require destruction of the horse orare invasive, inducing non- physiologic variables. In vitro techniques have also been reported for the evaluation of the effects of vasoactive agents on the digital vessels. The in vitro techniques are non-physiologic and have evaluated the vasculature proximal to the coronary band. Lastly, many of these techniques require general anesthesia or euthanasia of the animal. Laser Doppler flowmetry is a non-invasive, continuous measure of capillary blood flow. Laser Doppler flowmetry has been used to measure capillary blood flow in many tissues. The principle of this method is to measure the Doppler shift, that is, the frequency change that light undergoes when reflected by moving objects, such as red blood cells. Laser Doppler flowmetry records a continuous measurement of the red cell motion in the outer layer of the tissue under study, with little or no influence on physiologic blood flow. This output value constitutes the flux of red cells and is reported as capillary perfusion units. No direct information concerning oxygen, nutrient or waste metabolite exchange in the surrounding tissue is obtained. The relationship between the flowmeter output signal and the flux of red blood cells is linear. The principles of laser Doppler flowmetry will be discussed and the technique for laminar capillary blood flow measurements will be presented.

  8. Deep vein thrombosis of lower extremity: What is the most important finding in duplex Doppler sonography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yong Soo; Koh, Byung Hee; Cho, On Koo; Rhim, Hyun Chul; Seo, Heung Suk; Hahm, Chang Kok; Kwak, Jin Young [Hanyang University College of Medicine, Seoul (Korea, Republic of)

    1993-12-15

    The positive findings of deep vein thrombosis on duplex Doppler ultrasonography such as intraluminal clot,non-compressibility of the venous lumen and abnormal or absent Doppler shift signal are well known. However, relatively hypoechoic thrombus is not always seen in sonography, and the vein is frequently compressible in partial thrombosis. In order to evaluate the most common and important findings of deep vein thrombosis, we analysed the findings at duplex Doppler ultrasound in 19 patients and compared the results with those of contrast venography in 11 patients. Duplex Doppler ultrasound examination of the common femoral and popliteal veins was performed for one extremity in 14 patients, and for both extremities in 5 (total 24 extremities). Contrast venography was performed for one extremity in 7 patients, and for both sides in 4 (total 15 extremities).Thrombosis was seen in 45.8%, non-compressibility of lumen in 75%, absent or decreased Doppler signal from common femoral vein in 95.8%. Thrombosis was seen in 41.7%, non-compressibility of lumen in 70.8%, absent or decreased Doppler shift signal from popliteal vein in 95.8%. We conclude that abnormal or absent Doppler shift signal is the most sensitive and important finding of the deep vein thrombosis

  9. Verification of MC{sup 2}-3 Doppler Sample Models in ZPPR-15 D Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Min Jae; Hartanto, Donny; Kim, Sang Ji [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    In this paper, the change of reaction rate and broadened cross section were estimated by as-built MCNP models for metallic uranium sample in ZPPR-15D using ENDF/B-VII.0 library, and the results were compared with deterministic calculations provided in previous work. The Doppler broadening is an instant feedback mechanism that improves safety and stability for both thermal and fast reactors. Therefore, the accuracy of Doppler coefficient becomes an important parameter in reactor design as well as in the safety analysis. The capability of the Doppler worth calculation by a modern computer code suites such as MC2-3 and DIF3DVARIANT, has been validated against the Zero Power Physics Reactor-15 (ZPPR-15) Doppler worth measurement experiments. For the same experiments, our previous work suggested four different MC2-3 Doppler sample models for enhanced accuracy, which are combinations of heterogeneous models and the super cell approach. The MOC and MOC-SPC models showed the smallest error in estimating the U-238 total cross section of Doppler sample N-11, and the Doppler broadening effects are well applied to the cross section compared to other two models, HOM and SPC. The effects of the super cell approach can be hardly seen, since the broadened cross section is almost the same with and without the super cell approach. Comparing the transition of reaction density, MOC and MOC-SPC models also show similar behavior as MCNP's with minor errors. As a conclusion, we could obtain more consistent broadened cross section as well as reaction density transition by providing heterogeneous models from MC2-3's MOC module.

  10. Correção da origem anômala de artéria coronária esquerda com insuficiência mitral e hemólise mecânica Correction of anomalous origin of left coronary artery with mitral insufficiency and mechanical hemolisys

    Directory of Open Access Journals (Sweden)

    José Alberto Caliani

    2004-12-01

    Full Text Available Criança do sexo feminino, 2 meses de idade, apresentando quadro clínico de insuficiência cardíaca e sopro. Durante a investigação, foi realizado ecocardiograma e estudo cineangiocardiográfico que evidenciaram origem anômala da artéria coronária esquerda do tronco pulmonar e insuficiência mitral importante demonstrada ao doppler. A paciente foi submetida a tratamento cirúrgico com auxílio de circulação extracorpórea, que consistiu no reimplante da artéria coronária esquerda na aorta, associado à anuloplastia da valva mitral. No pós-operatório tardio, houve importante hemólise mecânica ocasionada pela plastia mitral. A paciente foi reoperada para remoção de retalho de pericárdio bovino. O ecocardiograma pós-operatório mostra insuficiência mitral leve e o paciente apresenta-se em classe funcional I (NYHA.A 2 months-old girl, presenting with heart failure and murmur was investigated using echocardiography and cardiac cathetherization revealing an anomalous left coronary artery origin from the pulmonary trunk and massive mitral regurgitation. The patient was submitted to surgery under cardiopulmonary bypass: the anomalous coronary was implanted in the aorta and the mitral valve repaired by annuloplasty. In the postoperative period the patient had important mechanical hemolysis caused by mitral annuloplasty. The patient underwent a second intervention to remove a piece of bovin pericardium. A postoperative echocardiogram revealed mild mitral insufficiency and the patient is free of symptoms.

  11. Uncertainty of Doppler reactivity worth due to uncertainties of JENDL-3.2 resonance parameters

    Energy Technology Data Exchange (ETDEWEB)

    Zukeran, Atsushi [Hitachi Ltd., Hitachi, Ibaraki (Japan). Power and Industrial System R and D Div.; Hanaki, Hiroshi; Nakagawa, Tuneo; Shibata, Keiichi; Ishikawa, Makoto

    1998-03-01

    Analytical formula of Resonance Self-shielding Factor (f-factor) is derived from the resonance integral (J-function) based on NR approximation and the analytical expression for Doppler reactivity worth ({rho}) is also obtained by using the result. Uncertainties of the f-factor and Doppler reactivity worth are evaluated on the basis of sensitivity coefficients to the resonance parameters. The uncertainty of the Doppler reactivity worth at 487{sup 0}K is about 4 % for the PNC Large Fast Breeder Reactor. (author)

  12. Spacecraft Doppler tracking with possible violations of LLI and LPI: a theoretical modeling

    International Nuclear Information System (INIS)

    Deng Xue-Mei; Xie Yi

    2014-01-01

    Currently two-way and three-way spacecraft Doppler tracking techniques are widely used and play important roles in control and navigation of deep space missions. Starting from a one-way Doppler model, we extend the theory to two-way and three-way Doppler models by making them include possible violations of the local Lorentz invariance (LLI) and the local position invariance (LPI) in order to test the Einstein equivalence principle, which is the cornerstone of general relativity and all other metric theories of gravity. After taking the finite speed of light into account, which is the so-called light time solution (LTS), we make these models depend on the time of reception of the signal only for practical convenience. We find that possible violations of LLI and LPI cannot affect two-way Doppler tracking under a linear approximation of LTS, although this approximation is sufficiently good for most cases in the solar system. We also show that, in three-way Doppler tracking, possible violations of LLI and LPI are only associated with two stations, which suggests that it is better to set the stations at places with significant differences in velocities and gravitational potentials to obtain a high level of sensitivity for the tests

  13. High-frequency dual mode pulsed wave Doppler imaging for monitoring the functional regeneration of adult zebrafish hearts

    OpenAIRE

    Kang, Bong Jin; Park, Jinhyoung; Kim, Jieun; Kim, Hyung Ham; Lee, Changyang; Hwang, Jae Youn; Lien, Ching-Ling; Shung, K. Kirk

    2015-01-01

    Adult zebrafish is a well-known small animal model for studying heart regeneration. Although the regeneration of scars made by resecting the ventricular apex has been visualized with histological methods, there is no adequate imaging tool for tracking the functional recovery of the damaged heart. For this reason, high-frequency Doppler echocardiography using dual mode pulsed wave Doppler, which provides both tissue Doppler (TD) and Doppler flow in a same cardiac cycle, is developed with a 30 ...

  14. Wayside Bearing Fault Diagnosis Based on a Data-Driven Doppler Effect Eliminator and Transient Model Analysis

    Science.gov (United States)

    Liu, Fang; Shen, Changqing; He, Qingbo; Zhang, Ao; Liu, Yongbin; Kong, Fanrang

    2014-01-01

    A fault diagnosis strategy based on the wayside acoustic monitoring technique is investigated for locomotive bearing fault diagnosis. Inspired by the transient modeling analysis method based on correlation filtering analysis, a so-called Parametric-Mother-Doppler-Wavelet (PMDW) is constructed with six parameters, including a center characteristic frequency and five kinematic model parameters. A Doppler effect eliminator containing a PMDW generator, a correlation filtering analysis module, and a signal resampler is invented to eliminate the Doppler effect embedded in the acoustic signal of the recorded bearing. Through the Doppler effect eliminator, the five kinematic model parameters can be identified based on the signal itself. Then, the signal resampler is applied to eliminate the Doppler effect using the identified parameters. With the ability to detect early bearing faults, the transient model analysis method is employed to detect localized bearing faults after the embedded Doppler effect is eliminated. The effectiveness of the proposed fault diagnosis strategy is verified via simulation studies and applications to diagnose locomotive roller bearing defects. PMID:24803197

  15. Outlier Detection in GNSS Pseudo-Range/Doppler Measurements for Robust Localization

    Directory of Open Access Journals (Sweden)

    Salim Zair

    2016-04-01

    Full Text Available In urban areas or space-constrained environments with obstacles, vehicle localization using Global Navigation Satellite System (GNSS data is hindered by Non-Line Of Sight (NLOS and multipath receptions. These phenomena induce faulty data that disrupt the precise localization of the GNSS receiver. In this study, we detect the outliers among the observations, Pseudo-Range (PR and/or Doppler measurements, and we evaluate how discarding them improves the localization. We specify a contrario modeling for GNSS raw data to derive an algorithm that partitions the dataset between inliers and outliers. Then, only the inlier data are considered in the localization process performed either through a classical Particle Filter (PF or a Rao-Blackwellization (RB approach. Both localization algorithms exclusively use GNSS data, but they differ by the way Doppler measurements are processed. An experiment has been performed with a GPS receiver aboard a vehicle. Results show that the proposed algorithms are able to detect the ‘outliers’ in the raw data while being robust to non-Gaussian noise and to intermittent satellite blockage. We compare the performance results achieved either estimating only PR outliers or estimating both PR and Doppler outliers. The best localization is achieved using the RB approach coupled with PR-Doppler outlier estimation.

  16. Spectral color Doppler in the diagnosis and follow-up of Graves' disease

    International Nuclear Information System (INIS)

    Sponza, Massimo; Bertolotto, Michele; Ricci, Claudio; Fabris, Bruno; Armini, Lorenzo

    1997-01-01

    Hyperthyroidism in Graves' disease is caused by the presence of circulating autoantibodies to the THS receptors on the thyroid cells. Thyroid-suppression therapy prevents hormone production directly, without affecting the pathogenetic process. They performed color Doppler US of the thyroid gland and pulsed Doppler analysis of thyroid artery flow in 21 patients with Graves' disease before and during medical treatment. US results were compared with those of a control group of 40 healthy subjects and correlated with the values of thyroid hormones, TSH and thyroid microsomal and thyroglobulin antibodies. The thyroid gland was hypo vascularized in the control group. Pulsed Doppler examination of the thyroid arteries exhibited peak systolic velocity of PSV 20 ± 4 cm/s, diastolic velocity of 8 ± 1 cm/s, and resistive index of 0.60 ± 0.04. The thyroid gland of Graves' disease patients was hyper vascularized. Pulsed Doppler examination of the thyroid arteries exhibited peak systolic velocity (PSV = 51 ± 12 cm/s), end diastolic velocity (VD = 15 ± 4 cm/s) and resistive index (RI = 0.71 ± 0.04) significantly higher than in normal subjects (p < 0.001). Circulating thyroid hormones and flow parameters normalized after 6-8 months of medical therapy (PSV = 20 ± 6 cm/s, VD = 9 ± 3 cm(s, RI = 0.58 ± 0.07). The color Doppler patterns normalized only in a patient with normal TSH and antibodies. Sampling of the thyroid arteries proved more repeatable than sampling of parenchymal vessels

  17. Effect of Casmo-5 cross-section data and doppler temperature definitions on LWR reactivity initiated accidents - 166

    International Nuclear Information System (INIS)

    Grandi, G.; Smith, K.; Xu, Z.; Rhodes, J.

    2010-01-01

    During LWR Reactivity Initiated Accidents (RIA), the accurate evaluation of the Doppler reactivity feedback depends on the Doppler coefficient computed by the lattice physics code (e.g. CASMO-5), and on the effective Doppler temperature computed by the transient code (e.g. SIMULATE-3K) using the non-uniform intra-pellet temperature profile. CASMO-5 has many new features compared with its predecessor. Among them, the replacement of the L-library (based primarily on ENDF/B IV data) by the latest available nuclear data (ENDF/B VII.0), and the Monte Carlo based resonance elastic scattering model to overcome deficiencies in NJOY modeling have a significant impact on the fuel temperature coefficient, and hence on LWR RIA. The Doppler temperature effect in thermal reactors is driven by the 238 U absorption. The different effective Doppler temperature definitions, available in the literature, try to capture the considerable self-shielding of the 238 U absorption that occurs in the pellet surface by defining an appropriate fuel temperature to compute cross-sections. In this work, we investigate the effect of the nuclear data generated by CASMO-5 on RIA, as well as the impact of different effective Doppler temperature definitions, including one proposed by the authors. It is concluded: 1) LWR RIA evaluated using CASMO-5 cross section data will be milder because the energy released is ∼10% smaller; 2) the prompt enthalpy rise is barely affected by the choice of the Doppler temperature definition; and 3) the peak fuel enthalpy is affected by the choice of the Doppler temperature definition, the under-prediction of the Doppler reactivity by the 'NEA' Doppler temperature results in a conservative estimate of the peak fuel enthalpy. (authors)

  18. Power Doppler sonography and ultrasound contrast agent in assessing rheumatoid synovitis

    Directory of Open Access Journals (Sweden)

    F. Salaffi

    2011-09-01

    Full Text Available Pannus formation is a fundamental event in the pathogenesis of rheumatoid arthritis and its hypervascularisation seems to be crucial to the development of joint damage. High-resolution greyscale ultrasonography is a safe, quick, and inexpensive imaging tool that allows an accurate detection of even minimal morphostructural changes in patients with rheumatoid arthritis, including joint effusion, thickening of synovial membrane and bone erosions. More recently, power Doppler sonography has proved to be a reliable tool for semiquantitative assessment of the vascularity of the synovial tissue. The contrast-enhanced power Doppler sonography seems to be a helpful adjunct in assessing synovitis and the therapeutic response to the different therapies in patients with rheumatoid arthritis. The aim of this radiological vignette was to show a representative example of use of power Doppler sonography with contrast agent in assessing rheumatoid synovitis.

  19. Pulsed and Color Doppler Sonographic Findings of Penile Mondor' Disease

    Energy Technology Data Exchange (ETDEWEB)

    Han, Hye Yeon; Chung, Dong Jin; Kim, Kum Won; Hwang, Cheol Mog [University of Konyang School of Medicine, Daejeon (Korea, Republic of)

    2008-04-15

    Penile Mondor's disease is a rare disease that's characterized by thrombosis in the dorsal vein of the penis. Doppler ultrasonography (US) clearly visualizes dorsal vein thrombosis and the associated hemodynamic alterations. Previous studies have demonstrated the typical color Doppler US findings of superficial dorsal vein thrombosis without the flow signals in this area, yet this is insufficient to understand the hemodynamics in penile Mondor's disease. We report here for the first time a cavernosal artery flow signal pattern in a penile Mondor's disease patient, in addition to its previously reported classic US findings. In conclusion, the Doppler US findings of thrombus without blood flow in the superficial dorsal vein and the low-flow, high resistance in the cavernosal artery may be suggestive of penile Mondor's disease.

  20. Evaluation of renal allograft rejection by Doppler sonography and MR imaging

    International Nuclear Information System (INIS)

    Steinberg, H.V.; Nelson, R.C.; Murphy, F.B.; Baumgartner, B.R.; Bourke, E.; Delaney, V.B.; Whelchel, J.B.; Bernardino, M.E.

    1986-01-01

    The authors prospectively studies the efficacy of Doppler sonography and MR imaging in evaluating renal allografts, with specific attention to transplant rejection. Based on study findings, we were unable to make a statement with respect to the appearance or accuracy of diagnosing cyclosporin toxicity or acute tubular necrosis by either modality due to concomitant rejection in the few patients so afflicted. Moreover, the ability to predict and diagnose the presence or absence of allograft rejection was not affected by different serum creatinine values. Most important, however, Doppler sonography was shown to be superior to MR imaging in evaluating for allograft rejection, as evidenced by its higher sensitivity (100% vs. 71%), specificity (88% vs. 75%), and accuracy (96% vs. 73%). Thus, because of its low cost and ease of accessibility, Doppler sonography should become the primary modality for renal transplant screening

  1. Discrimination between pleural thickening and minimal pleural effusion using color Doppler chest ultrasonography

    Directory of Open Access Journals (Sweden)

    Ali A. Hasan

    2013-07-01

    Conclusions: Application of color Doppler examination increases the accuracy of real time chest ultrasound to discriminate pleural thickening from minimal pleural effusion and hence color Doppler examination proved to be a useful diagnostic tool to real-time gray-scale ultrasound for diagnosis of minimal pleural effusion.

  2. Doppler broadening measurements in FRX-C/LSM

    International Nuclear Information System (INIS)

    Baron, M.H.; Chrien, R.E.

    1989-01-01

    Measurements obtained in situ during field reversed configuration (FRC) formation show that the Doppler broadening ion temperature T CV is larger by a factor of two or more than the ion temperature T i derived from pressure balance and Thomson scattering. After a time comparable to an ion-ion equilibrium time, T CV and T i come into agreement with each other. An exception to this picture occurs in the lowest fill pressure condition (2 mtorr), for which T CV > T i is maintained throughout the FRC lifetime. Earlier Doppler broadening measurements in FRX-B and FRX-C also showed persistent, anomalously high T CV at low fill pressure. The initially high values of T CV are probably caused by convective motion generated by the radial implosion. The low fill pressure results suggest an enhanced ohmic power input to the carbon ions. 7 refs., 3 figs

  3. Portal blood flow volume measurement in schistosomal patients: evaluation of Doppler ultrasonography reproducibility

    International Nuclear Information System (INIS)

    Leao, Alberto Ribeiro de Souza; Santos, Jose Eduardo Mourao; Moulin, Danilo Sales; Shigueoka, David Carlos; D'Ippolito, Giuseppe; Colleoni, Ramiro

    2008-01-01

    Objective: To evaluate the reproducibility of Doppler ultrasonography in the measurement of portal blood flow volume in schistosomal patients. Materials and methods: Prospective, transversal, observational and self-paired study evaluating 21 patients with hepatosplenic schistosomiasis submitted to Doppler ultrasonography performed by three independent observers for measurement of portal blood flow. Pairwise interobserver agreement was calculated by means of the intraclass correlation coefficient, paired t-test and Pearson's correlation coefficient. Results: Interobserver agreement was excellent. Intraclass correlation ranged from 80.6% to 93.0% (IC at 95% [65.3% ; 95.8%]), with the Pearson's correlation coefficient ranging between 81.6% and 92.7% with no statistically significant interobserver difference regarding the mean portal blood flow volume measured by Doppler ultrasonography (p = 0.954 / 0.758 / 0.749). Conclusion: Doppler ultrasonography has demonstrated to be a reliable method for measuring the portal blood flow volume in patients with portal hypertension secondary to schistosomiasis, with a good interobserver agreement. (author)

  4. Portal blood flow volume measurement in schistosomal patients: evaluation of Doppler ultrasonography reproducibility

    Energy Technology Data Exchange (ETDEWEB)

    Leao, Alberto Ribeiro de Souza; Santos, Jose Eduardo Mourao; Moulin, Danilo Sales; Shigueoka, David Carlos; D' Ippolito, Giuseppe [Universidade Federal de Sao Paulo (UNIFESP/EPM), SP (Brazil). Escola Paulista de Medicina. Dept. de Diagnostico por Imagem]. E-mail: ar.leao@uol.com.br; Colleoni, Ramiro [Universidade Federal de Sao Paulo (UNIFESP/EPM), SP (Brazil). Escola Paulista de Medicina. Dept. de Gastroenterologia

    2008-09-15

    Objective: To evaluate the reproducibility of Doppler ultrasonography in the measurement of portal blood flow volume in schistosomal patients. Materials and methods: Prospective, transversal, observational and self-paired study evaluating 21 patients with hepatosplenic schistosomiasis submitted to Doppler ultrasonography performed by three independent observers for measurement of portal blood flow. Pairwise interobserver agreement was calculated by means of the intraclass correlation coefficient, paired t-test and Pearson's correlation coefficient. Results: Interobserver agreement was excellent. Intraclass correlation ranged from 80.6% to 93.0% (IC at 95% [65.3% ; 95.8%]), with the Pearson's correlation coefficient ranging between 81.6% and 92.7% with no statistically significant interobserver difference regarding the mean portal blood flow volume measured by Doppler ultrasonography (p = 0.954 / 0.758 / 0.749). Conclusion: Doppler ultrasonography has demonstrated to be a reliable method for measuring the portal blood flow volume in patients with portal hypertension secondary to schistosomiasis, with a good interobserver agreement. (author)

  5. Changes in waveform on hepatic venous doppler in patients with chronic hepatic B: Correlation with histologic findings

    International Nuclear Information System (INIS)

    Ko, Joon Seok; Kim, Hak Soo; Chung, Dong Hae

    2001-01-01

    To evaluate changes of the waveform of the hepatic vein on doppler ultrasound (US) in patients with chronic hepatic B and to correlate them with histologic findings. Thirty three patients with chronic hepatic B were prospectively examined with doppler US, and liver biopsy was done at the same time. The right hepatic vein was examined on doppler US, and a liver biopsy was performed in the right lobe of the liver. Doppler waveform was considered abnormal if it showed either reduction in the amplitude of phasic oscillation without the reversed flow phase or the presence of completely flow. Specimens obtained from the biopsy were classified according to the predetermined histologic scoring criteria. It was technically possible to performed Doppler US of the right hepatic vein and liver biopsy simultaneously in all thirty three patients. Waveforms of the right hepatic vein were abnormal in fourteen (42.4%), biphasic in 12 (36.4%) and flat in two (6.0%) patients. Only the steatosis exhibited statistically significant correlation between changes of doppler waveform (p,0.05) of the normal and abnormal groups. Doppler US patterns of the hepatic vein in chronic hepatitis B were different from those of the normal group. The abnormal flow pattern on hepatic venous doppler appeared to be mainly influenced by the intrahepatic fat deposition rather than the degree of fibrosis.

  6. Power spectral density of velocity fluctuations estimated from phase Doppler data

    OpenAIRE

    Jicha Miroslav; Lizal Frantisek; Jedelsky Jan

    2012-01-01

    Laser Doppler Anemometry (LDA) and its modifications such as PhaseDoppler Particle Anemometry (P/DPA) is point-wise method for optical nonintrusive measurement of particle velocity with high data rate. Conversion of the LDA velocity data from temporal to frequency domain – calculation of power spectral density (PSD) of velocity fluctuations, is a non trivial task due to nonequidistant data sampling in time. We briefly discuss possibilities for the PSD estimation and specify limitations caused...

  7. Thermal Design for a Diffraction-Limited Doppler Spectrometer

    Data.gov (United States)

    National Aeronautics and Space Administration — The Univ. of Notre Dame is building a new high-resolution spectrometer named “iLocater” to achieve unprecedented radial velocity (RV) precision for stellar Doppler...

  8. Doppler-broadening of positron annihilation in a biological environment

    International Nuclear Information System (INIS)

    Torrisi, L.; La Mela, C.; Catania, Univ.

    1997-01-01

    The aim of this study was to investigate the Doppler effect of the 511 keV γ peak from positron annihilation in biological matter: The broadening of the annihilation peak is due to positron annihilation with electrons that have high momentum. In aqueous solutions annihilation depends on the temperature and it is linked positronium formation. Measurements in vivo, on human brain, were taken during the diagnosis of positron emission tomography (PET) on healthy patients by injecting them with the beta emitter of short lifetime 18F . The Doppler-broadening in biological tissues rich in water content decreased significantly compared to biological solutions and water

  9. Optical Doppler tomography based on a field programmable gate array

    DEFF Research Database (Denmark)

    Larsen, Henning Engelbrecht; Nilsson, Ronnie Thorup; Thrane, Lars

    2008-01-01

    We report the design of and results obtained by using a field programmable gate array (FPGA) to digitally process optical Doppler tomography signals. The processor fits into the analog signal path in an existing optical coherence tomography setup. We demonstrate both Doppler frequency and envelope...... extraction using the Hilbert transform, all in a single FPGA. An FPGA implementation has certain advantages over general purpose digital signal processor (DSP) due to the fact that the processing elements operate in parallel as opposed to the DSP. which is primarily a sequential processor....

  10. Doppler measurements of the ionosphere on the occasion of the Apollo-Soyuz test project. Part 1: Computer simulation of ionospheric-induced Doppler shifts

    Science.gov (United States)

    Grossi, M. D.; Gay, R. H.

    1975-01-01

    A computer simulation of the ionospheric experiment of the Apollo-Soyuz Test Project (ASTP) was performed. ASTP is the first example of USA/USSR cooperation in space and is scheduled for summer 1975. The experiment consists of performing dual-frequency Doppler measurements (at 162 and 324 MHz) between the Apollo Command Service Module (CSM) and the ASTP Docking Module (DM), both orbiting at 221-km height and at a relative distance of 300 km. The computer simulation showed that, with the Doppler measurement resolution of approximately 3 mHz provided by the instrumentation (in 10-sec integration time), ionospheric-induced Doppler shifts will be measurable accurately at all times, with some rare exceptions occurring when the radio path crosses regions of minimum ionospheric density. The computer simulation evaluated the ability of the experiment to measure changes of columnar electron content between CSM and DM (from which horizontal gradients of electron density at 221-km height can be obtained) and to measure variations in DM-to-ground columnar content (from which an averaged columnar content and the electron density at the DM can be deduced, under some simplifying assumptions).

  11. Sparse Representation Based Range-Doppler Processing for Integrated OFDM Radar-Communication Networks

    Directory of Open Access Journals (Sweden)

    Bo Kong

    2017-01-01

    Full Text Available In an integrated radar-communication network, multiuser access techniques with minimal performance degradation and without range-Doppler ambiguities are required, especially in a dense user environment. In this paper, a multiuser access scheme with random subcarrier allocation mechanism is proposed for orthogonal frequency division multiplexing (OFDM based integrated radar-communication networks. The expression of modulation Symbol-Domain method combined with sparse representation (SR for range-Doppler estimation is introduced and a parallel reconstruction algorithm is employed. The radar target detection performance is improved with less spectrum occupation. Additionally, a Doppler frequency detector is exploited to decrease the computational complexity. Numerical simulations show that the proposed method outperforms the traditional modulation Symbol-Domain method under ideal and realistic nonideal scenarios.

  12. The relationship between VHF radar auroral backscatter amplitude and Doppler velocity: a statistical study

    Directory of Open Access Journals (Sweden)

    B. A. Shand

    Full Text Available A statistical investigation of the relationship between VHF radar auroral backscatter intensity and Doppler velocity has been undertaken with data collected from 8 years operation of the Wick site of the Sweden And Britain Radar-auroral Experiment (SABRE. The results indicate three different regimes within the statistical data set; firstly, for Doppler velocities <200 m s–1, the backscatter intensity (measured in decibels remains relatively constant. Secondly, a linear relationship is observed between the backscatter intensity (in decibels and Doppler velocity for velocities between 200 m s–1 and 700 m s–1. At velocities greater than 700 m s–1 the backscatter intensity saturates at a maximum value as the Doppler velocity increases. There are three possible geophysical mechanisms for the saturation in the backscatter intensity at high phase speeds: a saturation in the irregularity turbulence level, a maximisation of the scattering volume, and a modification of the local ambient electron density. There is also a difference in the dependence of the backscatter intensity on Doppler velocity for the flow towards and away from the radar. The results for flow towards the radar exhibit a consistent relationship between backscatter intensity and measured velocities throughout the solar cycle. For flow away from the radar, however, the relationship between backscatter intensity and Doppler velocity varies during the solar cycle. The geometry of the SABRE system ensures that flow towards the radar is predominantly associated with the eastward electrojet, and flow away is associated with the westward electrojet. The difference in the backscatter intensity variation as a function of Doppler velocity is attributed to asymmetries between the eastward and westward electrojets and the geophysical parameters controlling the backscatter amplitude.

  13. The relationship between VHF radar auroral backscatter amplitude and Doppler velocity: a statistical study

    Directory of Open Access Journals (Sweden)

    B. A. Shand

    1996-08-01

    Full Text Available A statistical investigation of the relationship between VHF radar auroral backscatter intensity and Doppler velocity has been undertaken with data collected from 8 years operation of the Wick site of the Sweden And Britain Radar-auroral Experiment (SABRE. The results indicate three different regimes within the statistical data set; firstly, for Doppler velocities <200 m s–1, the backscatter intensity (measured in decibels remains relatively constant. Secondly, a linear relationship is observed between the backscatter intensity (in decibels and Doppler velocity for velocities between 200 m s–1 and 700 m s–1. At velocities greater than 700 m s–1 the backscatter intensity saturates at a maximum value as the Doppler velocity increases. There are three possible geophysical mechanisms for the saturation in the backscatter intensity at high phase speeds: a saturation in the irregularity turbulence level, a maximisation of the scattering volume, and a modification of the local ambient electron density. There is also a difference in the dependence of the backscatter intensity on Doppler velocity for the flow towards and away from the radar. The results for flow towards the radar exhibit a consistent relationship between backscatter intensity and measured velocities throughout the solar cycle. For flow away from the radar, however, the relationship between backscatter intensity and Doppler velocity varies during the solar cycle. The geometry of the SABRE system ensures that flow towards the radar is predominantly associated with the eastward electrojet, and flow away is associated with the westward electrojet. The difference in the backscatter intensity variation as a function of Doppler velocity is attributed to asymmetries between the eastward and westward electrojets and the geophysical parameters controlling the backscatter amplitude.

  14. Hepatic vein Doppler waveform in patients with diffuse fatty infiltration of the liver

    International Nuclear Information System (INIS)

    Oguzkurt, Levent; Yildirim, Tulin; Torun, Dilek; Tercan, Fahri; Kizilkilic, Osman; Niron, E. Alp

    2005-01-01

    Objective: To determine the incidence of abnormal hepatic vein Doppler waveform in patients with diffuse fatty infiltration of the liver (FIL). Materials and methods: In this prospective study, 40 patients with diffuse FIL and 50 normal healthy adults who served as control group underwent hepatic vein (HV) Doppler ultrasonography. The patients with the diagnosis of FIL were 23 men (57.5%) and 17 women aged 30-62 years (mean age ± S.D., 42 ± 12 years). Subjects in the control group were 27 men (54%) and 23 women aged 34-65 years (mean age ± S.D., 45 ± 14 years). The diagnosis of FIL was confirmed with computed tomography density measurements. The waveforms of HV were classified into three groups: regular triphasic waveform, biphasic waveform without a reverse flow, and monophasic or flat waveform. Etiological factors for FIL were diabetes mellitus (DM), hyperlipidemia and obesity (body mass index > 25). Serum lipid profile was obtained from all the patients with FIL. Results: Seventeen of the 40 patients (43%) with FIL had an abnormal HV Doppler waveform, whereas only one of the 50 (2%) healthy subjects had an abnormal waveform. The difference in the distribution of normal Doppler waveform pattern between the patients and the control group was significant (P 0.05). There was not any correlation between the degree of fat infiltration and the hepatic vein waveform pattern (P = 0.60). Conclusion: Patients with fatty liver has a high rate of an abnormal hepatic vein Doppler waveform pattern which can be biphasic or monophasic. We could not find a relation between the etiological factors for FIL and the occurrence of an abnormal HV Doppler waveform

  15. Doppler Sonographic Evaluation of Venogenic Extremity Swellings ...

    African Journals Online (AJOL)

    2017-09-14

    Sep 14, 2017 ... potentially lead to many complications including life-threatening pulmonary arterial thrombosis. Screening and confirmation ... and exclusion of acute lower extremity DVT. Duplex ultrasound is considered as the ... this study evaluates the role of Doppler sonography in the clinical management of suspected.

  16. [Postpartal ovarian thrombophlebitis. Value of Doppler ultrasonograph y].

    Science.gov (United States)

    Renaud-Giono, A; Giraud, J R; Poulain, P; Proudhon, J F; Grall, J Y; Moquet, P Y; Darnault, J P

    1996-01-01

    Thrombophlebitis of the ovarian vein is a well recognized but uncommon complication during the postpartum period. We report a small series and emphasize the contribution of color Doppler and the basic therapeutic measures.

  17. A micro-Doppler sonar for acoustic surveillance in sensor networks

    Science.gov (United States)

    Zhang, Zhaonian

    Wireless sensor networks have been employed in a wide variety of applications, despite the limited energy and communication resources at each sensor node. Low power custom VLSI chips implementing passive acoustic sensing algorithms have been successfully integrated into an acoustic surveillance unit and demonstrated for detection and location of sound sources. In this dissertation, I explore active and passive acoustic sensing techniques, signal processing and classification algorithms for detection and classification in a multinodal sensor network environment. I will present the design and characterization of a continuous-wave micro-Doppler sonar to image objects with articulated moving components. As an example application for this system, we use it to image gaits of humans and four-legged animals. I will present the micro-Doppler gait signatures of a walking person, a dog and a horse. I will discuss the resolution and range of this micro-Doppler sonar and use experimental results to support the theoretical analyses. In order to reduce the data rate and make the system amenable to wireless sensor networks, I will present a second micro-Doppler sonar that uses bandpass sampling for data acquisition. Speech recognition algorithms are explored for biometric identifications from one's gait, and I will present and compare the classification performance of the two systems. The acoustic micro-Doppler sonar design and biometric identification results are the first in the field as the previous work used either video camera or microwave technology. I will also review bearing estimation algorithms and present results of applying these algorithms for bearing estimation and tracking of moving vehicles. Another major source of the power consumption at each sensor node is the wireless interface. To address the need of low power communications in a wireless sensor network, I will also discuss the design and implementation of ultra wideband transmitters in a three dimensional

  18. Investigation of Doppler spectra of laser radiation scattered inside hand skin during occlusion test

    Science.gov (United States)

    Kozlov, I. O.; Zherebtsov, E. A.; Zherebtsova, A. I.; Dremin, V. V.; Dunaev, A. V.

    2017-11-01

    Laser Doppler flowmetry (LDF) is a method widely used in diagnosis of microcirculation diseases. It is well known that information about frequency distribution of Doppler spectrum of the laser radiation scattered by moving red blood cells (RBC) usually disappears after signal processing procedure. Photocurrent’s spectrum distribution contains valuable diagnostic information about velocity distribution of the RBC. In this research it is proposed to compute the indexes of microcirculation in the sub-ranges of the Doppler spectrum as well as investigate the frequency distribution of the computed indexes.

  19. Screening for aortoiliac lesions by visual interpretation of the common femoral Doppler waveform

    DEFF Research Database (Denmark)

    Eiberg, J P; Jensen, F; Grønvall Rasmussen, J B

    2001-01-01

    to study the accuracy of simple visual interpretation of the common femoral artery Doppler waveform for screening the aorto-iliac segment for significant occlusive disease.......to study the accuracy of simple visual interpretation of the common femoral artery Doppler waveform for screening the aorto-iliac segment for significant occlusive disease....

  20. Origin of short-period (30-300 s) Doppler frequency fluctuations of lower F region reflections in the equatorial electrojet region

    International Nuclear Information System (INIS)

    Sastri, J.H.; Ramesh, K.B.; Rao, J.V.S.V.; Somayajulu, V.V.

    1991-01-01

    Measurements of phase path P of lower F-region reflections at normal incidence at Kodaikanal revealed the ubiquitous presence of 30-300-s quasi-sinusoidal variations in the time rate of change of phase path, P (Doppler frequency shift) during day time. A study is made of the influence of the irregularities in the equatorial electrojet on the P fluctuations using simultaneous observations of F-region phase path at Kodaikanal and of equatorial electrojet with the VHF-backscatter radar at Thumba. It is shown that the spectral content of the Doppler fluctuations (quantified in terms of variance, sigma squared computed from P time series synthesized through FFT exp -1 (FFT) in the chosen period bands, 30-300 s/30-120 s of the FFT of original P times series) bears a significant positive linear relationship to the horizontal phase velocity of electrojet irregularities (3-m scale size) on a hourly basis. This result is in consonance with earlier findings (Sastri et al., 1990) of a significant linear relationship of sigma squared to the electrojet strength (estimated from H-field data) and a practical cessation of the P fluctuations at times of disappearance of Esq on ionograms (partial/complete counterelectrojet). The present work substantiates the interpretation that the short-period Doppler-frequency fluctuations are due to phase-path changes imposed on lower F region reflections by the refractive-index variations associated with the convective motions of plasma density irregularities (type I and II) in the daytime equatorial electrojet. 49 refs

  1. Power and color Doppler ultrasound settings for inflammatory flow: impact on scoring of disease activity in patients with rheumatoid arthritis.

    Science.gov (United States)

    Torp-Pedersen, Søren; Christensen, Robin; Szkudlarek, Marcin; Ellegaard, Karen; D'Agostino, Maria Antonietta; Iagnocco, Annamaria; Naredo, Esperanza; Balint, Peter; Wakefield, Richard J; Torp-Pedersen, Arendse; Terslev, Lene

    2015-02-01

    To determine how settings for power and color Doppler ultrasound sensitivity vary on different high- and intermediate-range ultrasound machines and to evaluate the impact of these changes on Doppler scoring of inflamed joints. Six different types of ultrasound machines were used. On each machine, the factory setting for superficial musculoskeletal scanning was used unchanged for both color and power Doppler modalities. The settings were then adjusted for increased Doppler sensitivity, and these settings were designated study settings. Eleven patients with rheumatoid arthritis (RA) with wrist involvement were scanned on the 6 machines, each with 4 settings, generating 264 Doppler images for scoring and color quantification. Doppler sensitivity was measured with a quantitative assessment of Doppler activity: color fraction. Higher color fraction indicated higher sensitivity. Power Doppler was more sensitive on half of the machines, whereas color Doppler was more sensitive on the other half, using both factory settings and study settings. There was an average increase in Doppler sensitivity, despite modality, of 78% when study settings were applied. Over the 6 machines, 2 Doppler modalities, and 2 settings, the grades for each of 7 of the patients varied between 0 and 3, while the grades for each of the other 4 patients varied between 0 and 2. The effect of using different machines, Doppler modalities, and settings has a considerable influence on the quantification of inflammation by ultrasound in RA patients, and this must be taken into account in multicenter studies. Copyright © 2015 by the American College of Rheumatology.

  2. Musculoskeletal colour/power Doppler in sports medicine: image parameters, artefacts, image interpretation and therapy

    DEFF Research Database (Denmark)

    Boesen, M I; Boesen, Mikael; Kønig, Merete Juhl

    2010-01-01

    This review article discusses the aspects of sports medicine where musculoskeletal Doppler ultrasound has valuable contribution in diagnosis and/or treatment of some of the typical musculoskeletal sports injuries. Also, conditions where the Doppler ultrasound has no value are discussed. Some...

  3. Musculoskeletal colour/power Doppler in sports medicine: image parameters, artefacts, image interpretation and therapy

    DEFF Research Database (Denmark)

    Boesen, M I; Boesen, Mikael; Kønig, Merete Juhl

    2011-01-01

    This review article discusses the aspects of sports medicine where musculoskeletal Doppler ultrasound has valuable contribution in diagnosis and/or treatment of some of the typical musculoskeletal sports injuries. Also, conditions where the Doppler ultrasound has no value are discussed. Some...

  4. Doppler Lidar Vertical Velocity Statistics Value-Added Product

    Energy Technology Data Exchange (ETDEWEB)

    Newsom, R. K. [DOE ARM Climate Research Facility, Washington, DC (United States); Sivaraman, C. [DOE ARM Climate Research Facility, Washington, DC (United States); Shippert, T. R. [DOE ARM Climate Research Facility, Washington, DC (United States); Riihimaki, L. D. [DOE ARM Climate Research Facility, Washington, DC (United States)

    2015-07-01

    Accurate height-resolved measurements of higher-order statistical moments of vertical velocity fluctuations are crucial for improved understanding of turbulent mixing and diffusion, convective initiation, and cloud life cycles. The Atmospheric Radiation Measurement (ARM) Climate Research Facility operates coherent Doppler lidar systems at several sites around the globe. These instruments provide measurements of clear-air vertical velocity profiles in the lower troposphere with a nominal temporal resolution of 1 sec and height resolution of 30 m. The purpose of the Doppler lidar vertical velocity statistics (DLWSTATS) value-added product (VAP) is to produce height- and time-resolved estimates of vertical velocity variance, skewness, and kurtosis from these raw measurements. The VAP also produces estimates of cloud properties, including cloud-base height (CBH), cloud frequency, cloud-base vertical velocity, and cloud-base updraft fraction.

  5. Evaluation of the patients with renovascular hypertension after percutaneous revascularization by Doppler ultrasonography

    International Nuclear Information System (INIS)

    Akan, Huseyin; Arik, Nurol; Saglam, Seher; Danaci, Murat; Incesu, Lutfi; Selcuk, Mustafa Bekir

    2003-01-01

    Objective: Evaluation of the effectiveness of percutaneous revascularization is based primarily on clinical criteria, and laboratory findings rather than direct investigation of luminal width. The purpose of this study was to evaluate the success of endovascular revascularization with serial Doppler ultrasound (US) examinations. Methods and material: 19 patients (14 were atherosclerotic, five were with fibromuscular dysplasia) with suspected renovascular hypertension treated by percutaneous revascularization were included in a prospective study. Patients had 23 renal artery stenoses reducing the diameter by more than 50%. Doppler US examinations were performed before intervention, and 1 day, 3 and 6 months after intervention. Results: Initial revascularization was technically successful in 21 of 23 stenoses (91.3%) (18 PTRA, three stent placement). Hypertension was cured in five atherosclerotic and in five fibromuscular dysplasia (FMD) patients, and improved in four atherosclerotic patients. Residual stenosis was determined in six patients and the others were evaluated as normal by initial postprocedure Doppler US. As based on Doppler US, restenosis (>60%-narrowing) was depicted in four of six (66.6%) renal arteries with residual stenosis, and one of 15 (6.6%) normal renal arteries at 1 year. This difference in restenosis rates (residual stenosis vs. normal) was significant (P<0.05). Conclusion: Positive predictor for recurrence was a residual renal artery stenosis documented by Doppler US 1 day after percutaneous revascularization in atherosclerotic cases

  6. Experimental verification of the inverse Doppler effect in negative-index material

    Science.gov (United States)

    Feng, Lie; Chen, Jiabi; Wang, Yan; Geng, Tao; Zhuang, Songlin

    2010-10-01

    μResearch of negative-index material (NIM) is a very hot developing research field in recent years. NIM is also called left-handed material (LHM), in which the electric field [see manuscript], the magnetic field [see manuscript] and the wave vector [see manuscript] are not composed of a set of right-handed coordinates but a set of left-handed coordinates. Thus the action of electromagnetic waves in both left-handed material and right-handed material is just the opposite, for instance, the negative refraction phenomenon, the inverse Doppler effect and so on. Here we report the explicit result of the inverse Doppler effect through a photonic crystal (PC) prism at 10.6m wavelength for the first time, and the result we get from the experiment is much similar to the theoretical analysis we have deduced before. During the experiment, the CO2 laser is used as a light source, and the PC prism is used as a sample, which can move a tiny distance (1mm) uniformly with a translating stage. Based on the method of optical heterodyne, we let the emergent light from the output surface of PC prism and the reference light from light source interfere at the surface of the detector. When the translating stage moves towards the detector, the optical paths in the PC prism will be changed, and then the Doppler frequency shift will be generated. Though several different samples have been tested repeatedly, the results we get are extraordinarily similar. So we can be sure that the inverse Doppler effect really exists in the NIM at optical frequencies. To our best knowledge, this is the only experimental verification of the inverse Doppler effect in the NIM at optical frequencies at home and aboard.

  7. Transcranial Doppler velocimetry in aneurysmal subarachnoid haemorrhage

    DEFF Research Database (Denmark)

    Staalsø, J M; Edsen, T; Romner, B

    2013-01-01

    -coded transcranial Doppler (TCCD), with the secondary aim of describing prediction of angiographic vasospasm and mortality. METHODS: /st>Sixty patients and 70 healthy controls were each examined in duplicate by alternating operators. A total of 939 measurements divided on 201 examination sets were conducted by four...

  8. Echobiometrics kidney and renal artery triplex doppler of canine fetuses

    Directory of Open Access Journals (Sweden)

    M.A.R. Feliciano

    2014-04-01

    Full Text Available The aim of this study was to assess the sogographic parameters and biometry of canine fetal kidneys using the B mode, and to determinate the vascular index of the fetal renal arteries using the Doppler Triplex. Twenty four Shi-tzu and Pug, weighting between 4 and 10kg, aging between 4 and 6 years old were evaluated. The B mode, the fetal renal echobiometry and regularity of the renal surface, echotexture and cortex:medular ratio were evaluated during the 5th, 6th, 7th and 8th weeks of pregnancy. At the same time point of the B mode evaluation, the Doppler Triplex was carried out to assess the sistolic peak velocity (SPV, end diastolic velocity (EDV, vascular resistive (RI and pulsatility index (PI. B mode revealed no fetal renal abnormalities and echobiometry showed important measurements during fetal development (P0.05. B mode and Doppler Triplex were important tools for the assessment of fetal renal development, using echobiometry and renal arterial index in canie fetuses.

  9. Study of retrobulbar hemodynamics in diabetes via color doppler ultrasound

    Directory of Open Access Journals (Sweden)

    Wei Chen

    2014-09-01

    Full Text Available AIM: To explore the changes of retrobulbar hemodynamics in diabetes via color doppler ultrasound. METHODS: Totally 80 patients(160 eyeswith eye diseases in type 2 diabetes from June 2010 to May 2013 in our hospital were enrolled as research group. By fundus photography and direct ophthalmoscopy, patients were assigned to diabetes without retinopathy group(DNR subgroup, non-proliferative diabetic retinopathy group(NPDR subgroupand proliferative diabetic retinopathy group(PDR subgroup. Of 60 healthy patients(120 eyesover the same period were chosen as control group. The doppler parameters of central retinal artery(CRA, posterior ciliary artery(PCAand ophthalmic artery(OAwere measured.RESULTS: There were significant differences on circulatory parameters of CRA, PCA and OA between both groups(PPPCONCLUSION: The monitoring of retinal blood flow and analysis of blood spectrum morphology via color doppler ultrasound can effectively evaluate the degree of diabetic retinopathy lesions, especially before DR vascular disease. Early detection can reveal the hemodynamic change pattern of DR, facilitating the prevention of diabetic eye complications and improvement of the quality of life.

  10. Adaptive OFDM Radar Waveform Design for Improved Micro-Doppler Estimation

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Satyabrata [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Engineering Science Advanced Research, Computer Science and Mathematics Division

    2014-07-01

    Here we analyze the performance of a wideband orthogonal frequency division multiplexing (OFDM) signal in estimating the micro-Doppler frequency of a rotating target having multiple scattering centers. The use of a frequency-diverse OFDM signal enables us to independently analyze the micro-Doppler characteristics with respect to a set of orthogonal subcarrier frequencies. We characterize the accuracy of micro-Doppler frequency estimation by computing the Cramer-Rao bound (CRB) on the angular-velocity estimate of the target. Additionally, to improve the accuracy of the estimation procedure, we formulate and solve an optimization problem by minimizing the CRB on the angular-velocity estimate with respect to the OFDM spectral coefficients. We present several numerical examples to demonstrate the CRB variations with respect to the signal-to-noise ratios, number of temporal samples, and number of OFDM subcarriers. We also analysed numerically the improvement in estimation accuracy due to the adaptive waveform design. A grid-based maximum likelihood estimation technique is applied to evaluate the corresponding mean-squared error performance.

  11. Direct measurement of Lorentz transformation with Doppler effects

    Science.gov (United States)

    Chen, Shao-Guang

    For space science and astronomy the fundamentality of one-way velocity of light (OWVL) is selfevident. The measurement of OWVL (distance/interval) and the clock synchronization with light-signal transfer make a logical circulation. This means that OWVL could not be directly measured but only come indirectly from astronomical method (Romer's Io eclipse and Bradley's sidereal aberration), furthermore, the light-year by definitional OWVL and the trigonometry distance with AU are also un-measurable. For to solve this problem two methods of clock synchronization were proposed: The direct method is that at one end of dual-speed transmissionline with single clock measure the arriving-time difference of longitudinal wave and transverse wave or ordinary light and extraordinary light, again to calculate the collective sending-time of two wave with Yang's /shear elastic-modulus ratio (E/k) or extraordinary/ordinary light refractive-index ratio (ne/no), which work as one earthquake-station with single clock measures first-shake time and the distance to epicenter; The indirect method is that the one-way wavelength l is measured by dual-counters Ca and Cb and computer's real-time operation of reading difference (Nb - Na) of two counters, the frequency f is also simultaneously measured, then l f is just OWVL. Therefore, with classical Newtonian mechanics and ether wave optics, OWVL can be measured in the Galileo coordinate system with an isotropic length unit (1889 international meter definition). Without any hypotheses special relativity can entirely establish on the metrical results. When a certain wavelength l is defined as length unit, foregoing measurement of one-way wavelength l will become as the measurement of rod's length. Let a rigidity-rod connecting Ca and Cb moves relative to lamp-house with velocity v, rod's length L = (Nb - Na) l will change follow v by known Doppler effect, i.e., L(q) =L0 (1+ (v/c) cos q), where L0 is the proper length when v= 0, v• r = v cos q

  12. The Doppler effect and the three most famous experiments for special relativity

    Directory of Open Access Journals (Sweden)

    Shukri Klinaku

    Full Text Available Using the general formula for the Doppler effect at any arbitrary angle, the three famous experiments for special theory of relativity will be examined. Explanation of the experiments of Michelson, Kennedy–Thorndike and Ives–Stilwell will be given in a precise and elegant way without postulates, arbitrary assumptions or approximations. Keywords: Doppler effect, Michelson experiment, Kennedy–Thorndike experiment, Ives–Stilwell experiment

  13. An assessment of methods of calculating Doppler effects in plutonium fuelled sodium cooled fast reactors

    International Nuclear Information System (INIS)

    Butland, A.T.D.; Reddell, G.

    1979-01-01

    After a survey of the requirements, an assessment of UK methods and data is made on the basis of the following work. First, the analysis of the SEFOR Doppler experiments, carried out using the UK FGL5 fine group nuclear data library, the MURAL cell code and whole reactor diffusion theory calculations of the neutron flux. Second, the analysis of some Japanese FCA central sample perturbation measurements of structural material Doppler effects. Third, an assessment of the accuracy of Doppler predictions in a sodium voided core using results from Zebra 5 and BIZET, and theoretical studies of additional effects relevant to power reactors and not covered by the above analyses, including the following, the calculation of Doppler effects at high temperature, fuel cycle and burn-up effects, and the heterogeneity effects of large fuelled subassemblies in pin geometry. The importance of crystalline binding effects in the fuel are discussed as is the importance of reactor material boundaries in the calculation of resonance shielding effects. Some suggestions for further Doppler studies are made. (U.K.)

  14. Three-dimensional power Doppler sonography: imaging and quantifying blood flow and vascularization.

    Science.gov (United States)

    Pairleitner, H; Steiner, H; Hasenoehrl, G; Staudach, A

    1999-08-01

    To assess the feasibility of imaging low-velocity blood flow in adnexal masses by transvaginal three-dimensional power Doppler sonography, to analyze three-dimensional power Doppler sonography data sets with a new computer-assisted method and to test the reproducibility of the technique. A commercially available 5-MHz Combison 530 ultrasound system was used to perform three-dimensional power Doppler sonography transvaginally. A cube (= volume of interest) was defined enclosing the vessels of the cyst and the Cartesian characteristics were stored on a hard disk. This cube was analyzed using specially designed software. Five indices representing vascularization (the vascularization index (VI) or blood flow (the flow index (FI)) or both (the vascularization-flow index (VFI)) were calculated. The intraobserver repeatability of cube definition and scan repetition was assessed using Hartley's test for homogeneous variances. Interobserver agreement was assessed by the Pearson correlation coefficient. Imaging of vessels with low-velocity blood flow by three-dimensional power Doppler sonography and cube definition was possible in all adnexal massed studied. In some cases even induced non-vascular flow related to endometriosis was detected. The calculated F value with intraobserver repeated Cartesian file-saving ranged from 0 to 18.8, with intraobserver scan repetition from 4.74 to 24.8 for VI, FI 1, FI 2 and VFI 1; for VFI 2 the calculated F value was 64. The interobserver correlation coefficient ranged between 0.83 and 0.92 for VI, FI 1, FI 2 and VFI 1; for VFI 2 the correlation coefficient was less than 0.75. Vessels with low-velocity blood flow can be imaged using three-dimensional power Doppler sonography. Induced non-vascular flow was detected in endometriotic cyst fluid. Three-dimensional power Doppler sonography combined with the cube method gave reproducible information for all indices except VFI 2. These indices might prove to be a new predictor in all fields of

  15. Full-wave Simulation of Doppler Reflectometry in the Presence of Turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Lechte, C. [Institut fur Plasmaforschung, Universitat Stuttgart, Stuttgart (Germany)

    2011-07-01

    Doppler reflectometry is a microwave plasma diagnostic well suited for density fluctuation measurement. A meaningful interpretation of Doppler reflectometry measurements necessitates the analysis of the wave propagation in the plasma using simulations methods. While the beam path can usually be reconstructed with beam tracing methods, the modeling of the scattering process demands the use of wave simulation codes. Furthermore, in the presence of strong density fluctuations, the response from the plasma is dominated by dispersion and multiple scattering, and hence becomes non-linear. IPF-FD3D is the finite difference time domain code used to investigate the dependence of the scattering efficiency on the various plasma conditions. It uses the full set of Maxwell equations and the electron equation of motion in a cold plasma. First results in slab geometry indicate a strong dependence of the scattering efficiency on the density gradient, the incident angle, and the wave polarisation. Further complications arise with the introduction of broadband turbulent fluctuations, where additional knowledge of the radial spectrum is necessary to reconstruct the full fluctuation spectrum from Doppler reflectometry measurements. This paper presents the reconstruction of the turbulent fluctuation spectrum from simulated Doppler reflectometry measurements in slab geometry. Two cases of analytical turbulence in slab geometry are presented where the fluctuation wavenumber spectrum was recovered. It is planned to extend these investigations to X mode polarization and to supplement actual fusion experiments

  16. Ambiguity Of Doppler Centroid In Synthetic-Aperture Radar

    Science.gov (United States)

    Chang, Chi-Yung; Curlander, John C.

    1991-01-01

    Paper discusses performances of two algorithms for resolution of ambiguity in estimated Doppler centroid frequency of echoes in synthetic-aperture radar. One based on range-cross-correlation technique, other based on multiple-pulse-repetition-frequency technique.

  17. Intratumoral vascularity of experimentally induced VX2 carcinoma : comparison of power doppler sonography and microangiography

    International Nuclear Information System (INIS)

    Park, Kil Sun; Won, Hyung Jin; Seo, Joon Beom; Kim, Tae Kyoung; Han, Joon Koo; Choi, Byung Ihn

    1997-01-01

    To evaluate the usefulness and limitations of power Doppler sonography in determining the tumor vascularity Power Doppler sonography was performed on VX2 carcinomas present in rabbit thighs, and the findings were compared with those of microangiography in an almost identical plane. Tumor vascularity was qualitatively analysed on the basis of tumor vessel distribution and density, and the presence of thick and thin vesels;for a comparison of tumor vascularity as seen on microangiography, tumor blood flow signals shown by power Doppler sonography were graded 3, 2, 1, 0. For quantitative analysis, a comparison was made of the percentage of tumor area occupied by vessels, as shown in each study. Data analysis utilized the Wilcoxon signed-rank test and Spearman correlation test. Mean tumor vascularity scores, as seen on power Doppler sonography and relating to tumor vessel distribution and density, and the presence of thick and thin vessels, were 2.87, 2.73, 2.93 and 2.73, respectively. The means and medians of the percentages of tumor area occupied by vessels were 22.7% and 23.5% and 36.4% and 34.7% on microangiography and power Doppler sonography, respectively. Thus, there was good correlation between these two modes. Power doppler sonography could demonstrate the tumor vascularity on microangiography relatively well but tend to overestimate it

  18. Prediction of cerebrovascular reserve by the MRI and doppler ultrasonography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hui Joong; Kim, Yong Sun [Kyungpook National University Hospital, Daegu (Korea, Republic of)

    2005-07-15

    We investigated acute stroke patterns on diffusion weighted images and with doppler ultrasonography studies of ICA and MCA steno-occlusive diseases in order to predict the cerbrovascular reserve (CVR), as was measured by acetazolamide (ACZ)-challenged Tc-99m ECD brain perfusion SPECT. A retrospective analysis was performed of 76 patients who underwent MRI/MRA, ACZ-challenged Tc-99m ECD brain perfusion SPECT, and carotid and vertebral artery Doppler sonography. After dividing these patients into four groups-MCA and ICA ateno-occlusions, we analyzed the relationship between the CVR and topologic MR patterns and the flow volume, as was measured by Doppler sonography. The CVRs were preserved in 26 of 76 patients. The CVRs were impaired in those cases of occlusion that were detected on MRA and also by the pattern of the territorial involvement on the diffusion weighted image ({rho} < 0.05, x{sup 2} test). Yet in cases of preserved CVRs, the flow volume of the contralateral ICA, the anterior circulation, and the total cerebral flow volume were increased, as was checked by Doppler sonography ({rho} < 0.05, t-test). As calculated by logistic regression analysis, the accuracy for predicting the preserved CVR by using the statistically significant variables was 78%. We believe that the MRI-SPECT correlation study was helpful for understanding the hemodynamics and topographic patterns of ischemia in patients with ICA and MCA steno-occlusive disease, and that the flow volume measurement, which was done by using duplex US, was useful for predicting the CVR.

  19. Power Doppler flow mapping and four-dimensional ultrasound for evaluating tubal patency compared with laparoscopy.

    Science.gov (United States)

    Soliman, Amr A; Shaalan, Waleed; Abdel-Dayem, Tamer; Awad, Elsayed Elbadawy; Elkassar, Yasser; Lüdders, Dörte; Malik, Eduard; Sallam, Hassan N

    2015-12-01

    To study the accuracy of four-dimensional (4D) ultrasound and power Doppler flow mapping in detecting tubal patency in women with sub-/infertility, and compare it with laparoscopy and chromopertubation. A prospective study. The study was performed in the outpatient clinic and infertility unit of a university hospital. The sonographic team and laparoscopic team were blinded to the results of each other. Women aged younger than 43 years seeking medical advice due to primary or secondary infertility and who planned to have a diagnostic laparoscopy performed, were recruited to the study after signing an informed consent. All of the recruited patients had power Doppler flow mapping and 4D hysterosalpingo-sonography by injecting sterile saline into the fallopian tubes 1 day before surgery. Registering Doppler signals, while using power Doppler, both at the tubal ostia and fimbrial end and the ability to demonstrate the course of the tube especially the isthmus and fimbrial end, while using 4D mode, was considered a patent tube. Out of 50 recruited patients, 33 women had bilateral patent tubes and five had unilateral patent tubes as shown by chromopertubation during diagnostic laparoscopy. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for two-dimensional power Doppler hysterosalpingography were 94.4%, 100%, 100%, 89.2%, and 96.2%, respectively and for 4D ultrasound were 70.4%, 100%, 100%, 70.4%, and 82.6%, respectively. Four-dimensional saline hysterosalpingography has acceptable accuracy in detecting tubal patency, but is surpassed by power Doppler saline hysterosalpingography. Power Doppler saline hysterosalpingography could be incorporated into the routine sub-/infertility workup. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  20. Ultrasonic Doppler color in glaucoma: Concordance study

    International Nuclear Information System (INIS)

    Uriza, Felipe; Useche, Nicolas

    2005-01-01

    Our study demonstrates that US color Doppler is a non invasive, reliable and reproducible method for the evaluation of the orbitary flow in normal and glaucomatous patients. However is suggested that every group evaluates the inter and intraobserver variability because of the lack of universal reference velocity measurements

  1. Aerosol distribution measurements by laser - Doppler - spectroscopy

    International Nuclear Information System (INIS)

    Baldassari, J.

    1977-01-01

    Laser-Doppler-Spectroscopy is used to study particle size distribution, especially sodium aerosols, in the presence of uncondensable gases. Theoretical basis are given, and an experimental technique is described. First theoretical results show reasonably good agreement with experimental data available; this method seems to be a promising one. (author)

  2. Doppler waveform study as indicator of change of portal pressure after administration of octreotide

    Science.gov (United States)

    Haider, Shahbaz; Hussain, Qurban; Tabassum, Sumera; Hussain, Bilal; Durrani, Muhammad Rasheed; Ahmed, Fayyaz

    2016-01-01

    Objective: To estimate the effect of portal pressure lowering drug ‘octreotide’, by observing the Doppler waveform before and after the administration of intravenous bolus of octreotide and thus to assess indirectly its efficacy to lower the portal pressure. Methods: This quassi experimental study was carried out in Medical Department in collaboration with Radiology Department of Jinnah Postgraduate Medical Center Karachi Pakistan from September 10, 2015 to February 5, 2016. Cases were selected from patients admitted in Medical Wards and those attending Medical OPD. Diagnosis of cirrhosis was confirmed by Clinical Examination and Lab & Imaging investigation in Medical Department. Doppler waveform study was done by experienced radiologist in Radiology Department before and after administration of octreotide. Doppler signals were obtained from the right hepatic vein. Waveform tracings were recorded for five seconds and categorized as ‘monophasic’, ‘biphasic’ and ‘triphasic’. Waveform changes from one waveform to other were noted and analyzed. Results: Significant change i.e. from ‘monophasic’ to ‘biphasic’ or ‘biphasic’ to ‘triphasic’ was seen in 56% cases while ‘monophasic’ to ‘triphasic’ was seen in 20% cases. No change was seen in 24% cases. Improvement in waveform reflects lowering of portal vein pressure. Conclusion: Non invasive Hepatic vein Doppler waveform study showed improvement in Doppler waveform after administration of octreotide in 76% cases. Doppler waveform study has the potential of becoming non invasive ‘follow up tool’ of choice for assessing portal pressure in patients having variceal bleed due to portal hypertension. PMID:27648043

  3. Color Doppler Ultrasonography-Targeted Perforator Mapping and Angiosome-Based Flap Reconstruction

    DEFF Research Database (Denmark)

    Gunnarsson, Gudjon Leifur; Tei, Troels; Thomsen, Jørn Bo

    2016-01-01

    Knowledge about perforators and angiosomes has inspired new and innovative flap designs for reconstruction of defects throughout the body. The purpose of this article is to share our experience using color Doppler ultrasonography (CDU)-targeted perforator mapping and angiosome-based flap reconstr......Knowledge about perforators and angiosomes has inspired new and innovative flap designs for reconstruction of defects throughout the body. The purpose of this article is to share our experience using color Doppler ultrasonography (CDU)-targeted perforator mapping and angiosome-based flap...

  4. Results of vardenafil mediated power Doppler ultrasound, contrast enhanced ultrasound and systematic random biopsies to detect prostate cancer.

    Science.gov (United States)

    Morelli, Girolamo; Pagni, Riccardo; Mariani, Chiara; Minervini, Riccardo; Morelli, Andrea; Gori, Francesco; Ferdeghini, Ezio Maria; Paterni, Marco; Mauro, Eva; Guidi, Elisa; Armillotta, Nicola; Canale, Domenico; Vitti, Paolo; Caramella, Davide; Minervini, Andrea

    2011-06-01

    We evaluated the ability of the phosphodiesterase-5 inhibitor vardenafil to increase prostate microcirculation during power Doppler ultrasound. We also evaluated the results of contrast and vardenafil enhanced targeted biopsies compared to those of standard 12-core random biopsies to detect cancer. Between May 2008 and January 2010, 150 consecutive patients with prostate specific antigen more than 4 ng/ml at first diagnosis with negative digital rectal examination and transrectal ultrasound, and no clinical history of prostatitis underwent contrast enhanced power Doppler ultrasound (bolus injection of 2.4 ml SonoVue® contrast agent), followed by vardenafil enhanced power Doppler ultrasound (1 hour after oral administration of vardenafil 20 mg). All patients underwent standard 12-core transrectal ultrasound guided random prostate biopsy plus 1 further sampling from each suspected hypervascular lesion detected by contrast and vardenafil enhanced power Doppler ultrasound. Prostate cancer was detected in 44 patients (29.3%). Contrast and vardenafil enhanced power Doppler ultrasound detected suspicious, contrast enhanced and vardenafil enhanced areas in 112 (74.6%) and 110 patients (73.3%), and was diagnostic for cancer in 32 (28.5%) and 42 (38%), respectively. Analysis of standard technique, and contrast and vardenafil enhanced power Doppler ultrasound findings by biopsy core showed significantly higher detection using vardenafil vs contrast enhanced power Doppler ultrasound and standard technique (41.2% vs 22.7% and 8.1%, p power Doppler ultrasound was 10% and 11.7% (p not significant). Vardenafil enhanced power Doppler ultrasound enables excellent visualization of the microvasculature associated with cancer and can improve the detection rate compared to contrast enhanced power Doppler ultrasound and the random technique. Copyright © 2011 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  5. The clinical study of 2D and power doppler ultrasound in esophagus varix

    International Nuclear Information System (INIS)

    Li Qiang; Zhou Liang; Zhang Yucheng; Yang Minghua; Ruan Fenglian; Lu Haixia; Li Yue

    2008-01-01

    Objective: To study the application of 2D and Power Doppler Ultrasound in diagnosing the abdominal esophageal varicose veins. Methods: 65 patients under suspicion with chronic hepatitis and cirrhosis for esophageal varicose at esophagus in abdomen section were examined by 2D and Power Doppler Ultrasound.Among them, 35 patients suffered from esophageal varicose veins proved by gastroscopy and the rest did not. Results: On the power doppler imaging map, colored blood stream signals were showed in varicose veins while without signals in non-varicose veins.The diagnostic sensitivity and specificity were 91.4% and 100% respectively. On the two-dimensional image chart, non-echoes were represented in varicose veins. The anteroposterior diameter, right-left diameter, as well as the thickness of esophagus wall were larger in patients with varicose veins than those in non varicose veins cases (P<0.01). Conclusion: 2D combined with Power Doppler Ultrasound was of non-invasive, safe, sensitive and high specificity, which is a valuable and practical tool in diagnosing the esophageal varicose veins. (authors)

  6. Ascitis fetal masiva idiopática aislada

    Directory of Open Access Journals (Sweden)

    Yolimar Navarro Briceño

    2016-08-01

    Full Text Available La ascitis fetal esta comúnmente asociada a malformaciones gastrointestinales y urinarias, anemia, infección y anomalías cromosómicas. La ascitis fetal masiva idiopática es rara. Se reporta un caso de una embarazada de 33 años referida a las 17 semanas después que se detectó ascitis en ausencia de anomalías estructurales. La evaluación cardiaca y las pruebas diagnósticas de infecciones virales fueron negativas. A las 28 semanas se detectó ascitis masiva sin otros signos de hidrops fetal. La velocidad sistólica pico de la arteria cerebral media fetal estaba elevada. El Doppler de la arteria umbilical, crecimiento fetal y volumen de líquido amniótico estaban normales. El ecocardiograma fetal estaba normal. Se realizó la amniocentesis con resultados normales del cariotipo. A pesar de la persistencia de la ascitis masiva durante el seguimiento, el crecimiento fetal y el volumen de líquido amniótico eran normales con valores elevados de la velocidad sistólica pico de la arteria cerebral media fetal. A las 33 semanas la paciente se realizó cesárea de emergencia por sufrimiento fetal agudo. Se obtuvo un recién nacido vivo femenino normal con valores normales de hemoglobina al nacer. El flujo vascular hepático, vesical y hepato-portal fueron normales. La ascitis se resolvió completamente al octavo día después del nacimiento y el recién nacido fue dado de alta a los 15 días.

  7. GPM GROUND VALIDATION DUAL-FREQUENCY DUAL-POLARIZED DOPPLER RADAR (D3R) IFLOODS V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GPM Ground Validation Dual-frequency Dual-polarized Doppler Radar (D3R) IFloodS data set contain radar reflectivity and doppler velocity measurements. The D3R...

  8. Can duplex Doppler ultrasound replace computerized tomography in staging patients with renal cell carcinoma?

    NARCIS (Netherlands)

    Bos, SD; Mensink, HJA

    The purpose of this study was to evaluate the accuracy and reliability of duplex Doppler ultrasound (US) and computerized tomography (CT) in staging patients with renal cell carcinoma (RCC). Sixty-six patients were evaluated pre-operatively with duplex Doppler ultrasound and CT. The results were

  9. Doppler echography and utilization of intravenous echo enhancer in the follow-up of hepato carcinoma with percutaneous radiological techniques; Ecografia Doppler y empleo del ecopotenciador intravenoso en el seguimiento del hepatocarcinoma con tecnicas radiologicas percutaneas

    Energy Technology Data Exchange (ETDEWEB)

    Forner, J; Flored de la Torre, M.; Senis, C; Lozano de Arnilla, M C; Ferrer, S; Celma, M I [Hospital General Universitario de Valencia. Valencia (Spain)

    2002-07-01

    To evaluate the utilization of Doppler ultrasound scan in conjunction with echographic enhancer in the follow-up of hepato carcinomas treated by means of radiological intervention techniques. We treated 20 hepatic nodules diagnosed with hepato carcinoma either by means of chemo embolization or percutaneously (either injection of acetic acid or radio-frequency thermo-ablation). Doppler ultrasound scan was performed before and after the treatment by means of sectorial and convex multifrequency probes. Evaluated were the absence, presence and degree of vascularisation, as well as its distribution and characteristics. In all cases, a contrast-en-handed spiral CT was performed. Both studies served as a pattern for comparison before and after treatment. In post-treatment enhanced-echo-Doppler controls of the 18 patients treated with acetic acid, vascularisation was not demonstrated in 7 cases, peripheral vascularisation was detected in 4 cases, perforation vascularisation in another four, and central vascularisation was detected in 3 cases. Contrast-enhanced spiral CT demonstrated superimposed findings, except in one cases, in which the spiral CT detected central capitation of the nodule.With enhanced echo-Doppler, peripheral vascularisation was detected. In both nodules treated by means of radio-frequency thermo ablation, there was detected neither vascularisation in the echo-Doppler nor captation of contrast media in the CT. Doppler ultrasound scan is a good method of follow-up for treated hepato carcinomas. The utilization of echoenhancers increases its ability to detect vascularization it being comparable to that of contrast-enhanced CT. As such, Doppler ultrasound scan together with echoenhancers can help us both in the selection of treatment and evaluation of therapeutic response. (Author) 35 refs.

  10. Laser doppler velocimetry and confined flows

    Directory of Open Access Journals (Sweden)

    Ilić Jelena T.

    2017-01-01

    Full Text Available Finding the mode, in which two component laser Doppler velocimetry can be applied to flows confined in cylindrical tubes or vessels, was the aim of this study. We have identified principle issues that influence the propagation of laser beams in laser Doppler velocimetry system, applied to flow confined in cylindrical tube. Among them, the most important are influences of fluid and wall refractive indices, wall thickness and internal radius ratio and beam intersection angle. In analysis of the degrees of these influences, we have applied mathematical model, based on geometrical optics. The separation of measurement volumes, that measure different velocity components, has been recognized as the main drawback. To overcome this, we propose a lens with dual focal length – primary focal length for the measurement of one velocity component and secondary focal length for the measurement of the other velocity component. We present here the procedure for calculating the optimal value of secondary focal length, depending on experimental set-up parameters. The mathematical simulation of the application of the dual focal length lens, for chosen cases presented here, confirmed the accuracy of the proposed procedure.

  11. Noncontact Detection and Analysis of Respiratory Function Using Microwave Doppler Radar

    Directory of Open Access Journals (Sweden)

    Yee Siong Lee

    2015-01-01

    Full Text Available Real-time respiratory measurement with Doppler Radar has an important advantage in the monitoring of certain conditions such as sleep apnoea, sudden infant death syndrome (SIDS, and many other general clinical uses requiring fast nonwearable and non-contact measurement of the respiratory function. In this paper, we demonstrate the feasibility of using Doppler Radar in measuring the basic respiratory frequencies (via fast Fourier transform for four different types of breathing scenarios: normal breathing, rapid breathing, slow inhalation-fast exhalation, and fast inhalation-slow exhalation conducted in a laboratory environment. A high correlation factor was achieved between the Doppler Radar-based measurements and the conventional measurement device, a respiration strap. We also extended this work from basic signal acquisition to extracting detailed features of breathing function (I : E ratio. This facilitated additional insights into breathing activity and is likely to trigger a number of new applications in respiratory medicine.

  12. Doppler ultrasonography of the anterior knee tendons in elite badminton players: colour fraction before and after match.

    Science.gov (United States)

    Koenig, M J; Torp-Pedersen, S; Boesen, M I; Holm, C C; Bliddal, H

    2010-02-01

    Anterior knee tendon problems are seldom reported in badminton players although the game is obviously stressful to the lower extremities. Painful anterior knee tendons are common among elite badminton players. The anterior knee tendons exhibit colour Doppler activity. This activity increases after a match. Painful tendons have more Doppler activity than tendons without pain. Cohort study. 72 elite badminton players were interviewed about training, pain and injuries. The participants were scanned with high-end ultrasound equipment. Colour Doppler was used to examine the tendons of 64 players before a match and 46 players after a match. Intratendinous colour Doppler flow was measured as colour fraction (CF). The tendon complex was divided into three loci: the quadriceps tendon, the proximal patellar tendon and the insertion on the tibial tuberosity. Interview: Of the 72 players, 62 players had problems with 86 tendons in the lower extremity. Of these 86 tendons, 48 were the anterior knee tendons. Ultrasound: At baseline, the majority of players (87%) had colour Doppler flow in at least one scanning position. After a match, the percentage of the knee complexes involved did not change. CF increased significantly in the dominant leg at the tibial tuberosity; single players had a significantly higher CF after a match at the tibial tuberosity and in the patellar tendon both before and after a match. Painful tendons had the highest colour Doppler activity. Most elite badminton players had pain in the anterior knee tendons and intratendinous Doppler activity both before and after match. High levels of Doppler activity were associated with self-reported ongoing pain.

  13. Biometric, B-mode and color Doppler ultrasound assessment of eyes in healthy dogs

    Directory of Open Access Journals (Sweden)

    Elzivânia G. Silva

    Full Text Available ABSTRACT: B-scan ultrasonography is an important diagnostic tool that allows characterization of internal organ anatomy and, when complemented by Doppler ultrasound, allows vascular hemodynamic assessment, increasing the diagnostic accuracy. Thus, the aim of the present study was the B-scan ultrasound characterization and measurement of the eyeball segments and assessment of the external ophthalmic artery by color and pulsed Doppler. Sixty eyeballs were assessed from 30 dogs of different breeds using an 8.5MHz microconvex transductor. First, biometry was performed by B-scan of the following segments: axial length (M1, anterior chamber depth (M2, lens thickness (M3, lens length (M4, vitreous chamber depth (M5, optical disc length (M6 and optic nerve diameter (M7. Colored Doppler identified the external ophthalmic article and pulsed Doppler assessed its flow, and the following were measured: systolic peak velocity (VPS, final diastolic velocity (VDF, resistivity index (IR and pulse index (IP. No statistical difference was observed for the biometric values of the eye segments between the right and left eyes (p>0.05. The vitreous chamber depth (M5 was shown to be the biometric variable with greatest bilateral symmetry, varying from 0.79 to 0.87cm and 0.78 to 0.86cm for the right and left eye, respectively. The ophthalmic artery was visualized over the optic nerve towards the eyeball, with flow stained red. There was no significant statistical difference between the Doppler velocimetric values for the ophthalmic artery between the right and left eye of the animals assessed (p>0.05. The mean resistivity index (RI showed average values equal to 0.63±0.03, bilaterally. The mean base velocity was 17.50cm/s and 18.18cm/s at the systolic peak and 6.21cm/s and 6.68cm/s at the end of the diastole, for the right and left eyes respectively. The anatomic, biometric and hemodynamic characterization using the ultrasound B-scan and the Doppler modalities

  14. A Wearable Transcranial Doppler Ultrasound Phased Array System.

    Science.gov (United States)

    Pietrangelo, Sabino J; Lee, Hae-Seung; Sodini, Charles G

    2018-01-01

     Practical deficiencies related to conventional transcranial Doppler (TCD) sonography have restricted its use and applicability. This work seeks to mitigate several such constraints through the development of a wearable, electronically steered TCD velocimetry system, which enables noninvasive measurement of cerebral blood flow velocity (CBFV) for monitoring applications with limited operator interaction. A highly-compact, discrete prototype system was designed and experimentally validated through flow phantom and preliminary human subject testing. The prototype system incorporates a custom two-dimensional transducer array and multi-channel transceiver electronics, thereby facilitating acoustic beamformation via phased array operation. Electronic steering of acoustic energy enables algorithmic system controls to map Doppler power throughout the tissue volume of interest and localize regions of maximal flow. Multi-focal reception permits dynamic vessel position tracking and simultaneous flow velocimetry over the time-course of monitoring. Experimental flow phantom testing yielded high correlation with concurrent flowmeter recordings across the expected range of physiological flow velocities. Doppler power mapping has been validated in both flow phantom and preliminary human subject testing, resulting in average vessel location mapping times testing. A wearable prototype CBFV measurement system capable of autonomous vessel search and tracking has been presented. Although flow phantom and preliminary human validation show promise, further human subject testing is necessary to compare velocimetry data against existing commercial TCD systems. Additional human subject testing must also verify acceptable vessel search and tracking performance under a variety of subject populations and motion dynamics-such as head movement and ambulation.

  15. The Doppler echocardiographic myocardial performance index predicts left-ventricular dilation and cardiac death after myocardial infarction

    DEFF Research Database (Denmark)

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

    2001-01-01

    To investigate the value of the Doppler-derived myocardial performance index to predict early left-ventricular (LV) dilation and cardiac death after a first acute myocardial infarction (AMI), Doppler echocardiography was performed within 24 h of hospital admission, on day 5, 1 and 3 months after...... AMI in 125 consecutive patients. The index measured on day 1 correlated well with the change in end-diastolic volume index observed from day 1 to 3 months following AMI (r = 0.66, p 0.0001). One-year survival in patients with Doppler index index > or = 0......, we conclude that the Doppler echocardiographic myocardial performance index is a predictor of LV dilation and cardiac death after a first AMI....

  16. Pulsed-wave tissue Doppler and color tissue Doppler echocardiography: calibration with M-mode, agreement, and reproducibility in a clinical setting

    DEFF Research Database (Denmark)

    Olsen, Niels Thue; Jons, Christian; Fritz-Hansen, Thomas

    2009-01-01

    BACKGROUND: Myocardial velocities can be measured with both pulsed-wave tissue Doppler (PWTD) and color tissue Doppler (CTD) echocardiography. We aimed to (A) to explore which of the two methods better approximates true tissue motion and (B) to examine the agreement and the reproducibility...... of the two methods in a routine clinical setting. METHODS: For Study A, the displacements of 63 basal myocardial segments from 13 patients were examined with M-mode and compared with the velocity-time integral of PWTD and CTD velocities. For Study B, the basal lateral segments from 58 patients were examined...... with PWTD and CTD, and the peak myocardial velocities during systole (Sm), early diastole (Em), and late diastole (Am) were measured. RESULTS: Study A: CTD-based measurements of displacement were 12% lower than M-mode measurements (95% CI: -18%; -6%). PWTD velocity-time integrals measured at the outer edge...

  17. An analytical model for the description of the full-polarimetric sea surface Doppler signature

    NARCIS (Netherlands)

    Fois, F.; Hoogeboom, P.; Le Chevalier, F.; Stoffelen, A.

    2015-01-01

    This paper describes an analytical model of the full-polarimetric sea surface scattering and Doppler signature. The model combines the small-slope-approximation theory (at the second order) with a weak nonlinear sea surface representation. Such a model is used to examine the variation of the Doppler

  18. Combination of serum angiopoietin-2 and uterine artery Doppler for prediction of preeclampsia.

    Science.gov (United States)

    Puttapitakpong, Ploynin; Phupong, Vorapong

    2016-02-01

    The aim of this study was to determine the predictive value of the combination of serum angiopoietin-2 (Ang-2) levels and uterine artery Doppler for the detection of preeclampsia in women at 16-18 weeks of gestation and to identify other pregnancy complications that could be predicted with these combined tests. Maternal serum Ang-2 levels were measured, and uterine artery Doppler was performed in 400 pregnant women. The main outcome was preeclampsia. The predictive values of this combination were calculated. Twenty-five women (6.3%) developed preeclampsia. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of uterine artery Doppler combined with serum Ang-2 levels for the prediction of preeclampsia were 24.0%, 94.4%, 22.2% and 94.9%, respectively. For the prediction of early-onset preeclampsia, the sensitivity, specificity, PPV and NPV were 57.1%, 94.1%, 14.8% and 99.2%, respectively. Patients with abnormal uterine artery Doppler and abnormal serum Ang-2 levels (above 19.5 ng ml(-1)) were at higher risk for preterm delivery (relative risk=2.7, 95% confidence interval 1.2-5.8). Our findings revealed that the combination of uterine artery Doppler and serum Ang-2 levels at 16-18 weeks of gestation can be used to predict early-onset preeclampsia but not overall preeclampsia. Thus, this combination may be a useful early second trimester screening test for the prediction of early-onset preeclampsia.

  19. Alveolar Echinococcosis of the Liver: Correlative Color Doppler US, CT, and MRI Study

    International Nuclear Information System (INIS)

    Cokun, A.; Oeztuerk, M.; Karahan, O.I.; Erdogan, N.; Ikin, S.; Guelec, M.

    2004-01-01

    Purpose: To determine and compare the imaging features of hepatic alveolar Echinococcosis using color Doppler US, CT, and MRI. Material and Methods: Abdominal CT and MRI with and without contrast agents and color Doppler US were performed on seven patients with hepatic alveolar Echinococcosis. The lesions were evaluated for location, features of echogenicity, intensity and density, calcification, and vascular, hilar, and perihepatic involvement. The diagnosis was confirmed histopathologically in all patients. Results: Six patients had solitary lesions, and one displayed multiple lesions. The lesions were generally seen as heterogeneous and hyper- or hypoechoic when imaged with color Doppler US, hypodense with CT, and hypointense with MRI, in comparison with the liver parenchyma. Calcification, central necrosis, and small peripheral cysts were observed in six, seven, and four patients, respectively. Vascular flow or contrast enhancement was not observed in any of the cases. A look at the respective advantages of each method reveals that calcification was best rendered visible via CT, small peripheral cysts with T2-weighted MRI, central necrosis with CT and MRI, and perihepatic invasion with multiplanar MRI. Vascular involvement was revealed by all methods. Conclusion: Color Doppler US, CT, and MR imaging function extremely well as complementary methods in the diagnosis of HAE. Color Doppler US should be performed in these patients owing to its ability to efficiently detect the disease. Knowledge of imaging characteristics makes it possible to radiologically ascertain an early diagnosis

  20. Fifty Years of HF Doppler Observations

    Directory of Open Access Journals (Sweden)

    T Ogawa

    2009-04-01

    Full Text Available High frequency Doppler observations of the ionosphere began in August of 1957 in Kyoto. The number of the observation points worldwide were about 40 in 1980 and are about 20 at present. By this method the movement of the ionosphere reflection height and electron density below the height can be observed. Such variations are occurred by a wide variety of sources.

  1. The Doppler Effect: A Consideration of Quasar Redshifts.

    Science.gov (United States)

    Gordon, Kurtiss J.

    1980-01-01

    Provides information on the calculation of the redshift to blueshift ratio introduced by the transverse Doppler effect at relativistic speeds. Indicates that this shift should be mentioned in discussions of whether quasars are "local" rather than "cosmological" objects. (GS)

  2. Time series analysis of continuous-wave coherent Doppler Lidar wind measurements

    DEFF Research Database (Denmark)

    Sjöholm, Mikael; Mikkelsen, Torben; Mann, Jakob

    2008-01-01

    The influence of spatial volume averaging of a focused 1.55 mu m continuous-wave coherent Doppler Lidar on observed wind turbulence measured in the atmospheric surface layer over homogeneous terrain is described and analysed. Comparison of Lidar-measured turbulent spectra with spectra simultaneou......The influence of spatial volume averaging of a focused 1.55 mu m continuous-wave coherent Doppler Lidar on observed wind turbulence measured in the atmospheric surface layer over homogeneous terrain is described and analysed. Comparison of Lidar-measured turbulent spectra with spectra...

  3. Color Doppler Score: A New Approach for Monitoring a Large Placental Chorioangioma

    Directory of Open Access Journals (Sweden)

    Maria Angelica Zoppi

    2014-01-01

    Full Text Available We employed color Doppler score as an innovative approach for the prenatal diagnosis and monitoring of a large placental chorioangioma case diagnosed at 26 weeks and the subjective semiquantitative assessment of the vascularization. The blood flow was assessed by a color Doppler score based on the intensity of the color signal with the following value ranges: (1 no flow, (2 minimal flow, (3 moderate flow, and (4 high vascular flow. Weekly examinations were programmed. Initially, a color Doppler score 3 was assigned, remaining unchanged at the following two exams and decreasing to Score 2 in the following 2 exams and to Score 1 thereafter. The ultrasonographic scan showed an increase of the mass size at the second and third exams and was followed by an arrest of the growth persisting for the rest of the pregnancy. Some hyperechogenic spots inside the mass appeared at the end. Expectant management was opted for, and the delivery was at 39, 2 weeks and maternal and fetal outcomes were favourable. The color Doppler score employed for assessment of vascularization in successive examinations proved to be an important tool for the prediction of the chorioangioma involution, and this new approach of monitoring allowed effective surveillance and successful tailored management.

  4. 99m-Tc DMSA scintigraphy and color/power doppler sonography for children pyelonephritis diagnosis and follow-up

    International Nuclear Information System (INIS)

    Hitzel, A.; Manrique, A.; Gardin, I.; Vera, P.; Hitzel, A.; Dacher, J.N.; Manrique, A.; Menard, J.F.; Gardin, I.; Vera, P.; Dacher, J.N.; Liard, A.; Menard, J.F.

    2004-01-01

    Early diagnosis of acute pyelonephritis is essential to avoid scarring development. This study was performed to evaluate capabilities of color/doppler sonography to detect pyelonephritis and to predict scarring when compared with 99m Tc-DMSA scintigraphy. Fifty-seven children were evaluated during pyelonephritis: biology (CRP, creatinine, blood formula), color/power doppler sonography and 99m Tc-DMSA scintigraphy (DMSA1). 7 ± 2 months later, follow-up consisted in biological tests and a 99m 'Tc-DMSA scintigraphy (DMSA2). During pyelonephritis, body temperature, CRP value and neutrophil counts were significantly higher in patients with an abnormal DMSA1 but not in patients with abnormal doppler sonography. When compared with DMSA1, doppler sonography sensitivity and specificity were 80% and 81% respectively. DMSA1 and doppler sonography were concordant in 86% of children with a pyelonephritis. At follow-up, all clinical et biological parameters were normalized. DMSA2 was abnormal in 51% of children. When compared with DMSA2, positive and negative predictive values for scarring of doppler sonography were 57% and 75% respectively. DMSA 1, positive and negative predictive values for scarring were 62% and 100%. In conclusion, color/power doppler sonography is a reliable tool for pyelonephritis diagnosis, but its predictive value for scarring is poor. Negative predictive value of DMSA scintigraphy is excellent. (author)

  5. Transthoracic Doppler echocardiography – noninvasive diagnostic window for coronary flow reserve assessment

    Directory of Open Access Journals (Sweden)

    Dimitrow Paweł

    2003-04-01

    Full Text Available Abstract This review focuses on transthoracic Doppler echocardiography as noninvasive method used to assess coronary flow reserve (CFR in a wide spectrum of clinical settings. Transthoracic Doppler echocardiography is rapidly gaining appreciation as popular tool to measure CFR both in stenosed and normal epicardial coronary arteries (predominantly in left anterior descending coronary artery. Post-stenotic CFR measurement is helpful in: functional assessment of moderate stenosis, detection of significant or critical stenosis, monitoring of restenosis after revascularization. In the absence of stenosis in the epicardial coronary artery, decreased CFR enable to detect impaired microvascular vasodilatation in: reperfused myocardial infarct, arterial hypertension with or without left ventricular hypertrophy, diabetes mellitus, hypercholesterolemia, syndrome X, hypertrophic cardiomyopathy. In these diseases, noninvasive transthoracic Doppler echocardiography allows for serial CFR evaluations to explore the effect of various pharmacological therapies.

  6. Spectral color Doppler in the diagnosis and follow-up of Graves` disease; Ruolo dell`eco color Doppler e dell`analisi flussimetrica nella diagnosi e nel follow-up della malattia dei Graves

    Energy Technology Data Exchange (ETDEWEB)

    Sponza, Massimo; Bertolotto, Michele; Ricci, Claudio [Ospedale di Cattinara, Trieste (Italy). Istituto di Medicina Clinica; Fabris, Bruno; Armini, Lorenzo [Ospedale di Cattinara, Trieste (Italy). Istituto di Radiologia

    1997-04-01

    Hyperthyroidism in Graves` disease is caused by the presence of circulating autoantibodies to the THS receptors on the thyroid cells. Thyroid-suppression therapy prevents hormone production directly, without affecting the pathogenetic process. They performed color Doppler US of the thyroid gland and pulsed Doppler analysis of thyroid artery flow in 21 patients with Graves` disease before and during medical treatment. US results were compared with those of a control group of 40 healthy subjects and correlated with the values of thyroid hormones, TSH and thyroid microsomal and thyroglobulin antibodies. The thyroid gland was hypo vascularized in the control group. Pulsed Doppler examination of the thyroid arteries exhibited peak systolic velocity of PSV 20 {+-} 4 cm/s, diastolic velocity of 8 {+-} 1 cm/s, and resistive index of 0.60 {+-} 0.04. The thyroid gland of Graves` disease patients was hyper vascularized. Pulsed Doppler examination of the thyroid arteries exhibited peak systolic velocity (PSV = 51 {+-} 12 cm/s), end diastolic velocity (VD = 15 {+-} 4 cm/s) and resistive index (RI = 0.71 {+-} 0.04) significantly higher than in normal subjects (p < 0.001). Circulating thyroid hormones and flow parameters normalized after 6-8 months of medical therapy (PSV = 20 {+-} 6 cm/s, VD = 9 {+-} 3 cm/s, RI = 0.58 {+-} 0.07). The color Doppler patterns normalized only in a patient with normal TSH and antibodies. Sampling of the thyroid arteries proved more repeatable than sampling of parenchymal vessels.

  7. Usefulness of color and pulsed Doppler's in the evaluation of surgical portosystemic shunts in pediatric patients; Utilidad del Doppler color y pulsado en la valoracion de los shunts portosistemicos quirurgicos en la edad pediatrica

    Energy Technology Data Exchange (ETDEWEB)

    Berrocal, T.; Prieto, C.; Cortes, P.; Rodriguez, R.; Pastor, I. [Hospital Universitario La Paz. Madrid (Spain)

    2003-07-01

    Portosystemic shunts are performed to relieve symptomatic portal hypertension symptomatic or removal pressure in hepatic vascularisation in patients with Budd-Chiari's syndrome. Most surgical portosystemic shunts can be suitably studied by means of ultrasound scan complemented by color and pulsed Dopplers, proved one understands the hemodynamics of the surgical procedures involved. This article demonstrates the usefulness and limitations of the ultrasound scan Duplex Doppler in the evaluation of portosystemic shunts performed on pediatric patients. Pulsed Doppler provides information regarding the nature and direction of blood flow. Color doppler is capable of directly revealing the shunt and, in most cases, permits the anastomosis to be located. The types of shunts that appear include proximal and distal spleno-renal, portocaval and mesocaval. Types of vascular connections are illustrated,s well as expected post-surgical blood flow direction in affected vessels. The ultrasound scanning technique is discussed, as well as the criteria for determining vascular permeability. Also highlighted are the advantages, limitations and diagnostic difficulties associated with the different forms of Doppler. (Author) 17 refs.

  8. Atomic stopping-power problems encountered in measurements of nuclear γ-ray lifetimes by the Doppler-shift-attenuation method

    International Nuclear Information System (INIS)

    Latta, B.M.; Scanlon, P.J.

    1976-01-01

    The value of the nuclear lifetime of the 3.34-MeV level in 22 Ne as determined by Broude et al. by the Doppler shift attenuation method exhibits variations depending on the atomic number Z 2 of the slowing down medium. The lifetime has been re-evaluated within the framework of the Lindhard-Winther stopping theory, assuming a simple approximate form for the density of electrons associated with an atom in a solid and an effective point charge for the projectile based on experimental stopping powers. Although there are still variations in the value of the lifetime the variations appear to be systematic through the region of the transition elements. (Auth.)

  9. Applications of doppler effect in navigation and oceanography

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, A.

    The Doppler effect is the change in frequency of the received sound waves/electromagnetic waves when there is a relative motion between the transmitter and the receiver of these waves. This effect is used for diverse applications in different areas...

  10. Tamizaje y prevención de pre-eclampsia guiado por Doppler de arterias uterinas: revisión sistemática de la literatura

    OpenAIRE

    Sáez O, Nicolás; Carvajal C, Jorge

    2012-01-01

    Antecedentes: La pre-eclampsia (PE) es una enfermedad grave asociada al embarazo con una prevalencia de ~3%. La identificación de las mujeres en riesgo podría mejorar el resultado materno y perinatal. La estimación de riesgo individual de PE permitiría ofrecer un tratamiento preventivo para ésta [ej: aspirina (AAS)]. Se ha descrito el Doppler de arterias uterinas (DAUt) en primer y segundo trimestre como un método de tamizaje de PE. Objetivo: Recopilar la evidencia disponible sobre el uso del...

  11. Doppler waveforms of the hepatic veins in children with diffuse fatty infiltration of the liver

    International Nuclear Information System (INIS)

    Uzun, Hakan; Yazici, Burhan; Erdogmus, Besir; Kocabay, Kenan; Buyukkaya, Ramazan; Buyukkaya, Ayla; Yazgan, Omer

    2009-01-01

    Objective: The aim of this study was to investigate the effect of fatty infiltration of the liver (FIL) on the Doppler waveform pattern in the hepatic veins of obese children. Methods: In this prospective study, 59 patients with diffuse FIL and 45 normal healthy children who served as control group underwent hepatic vein B-mod and duplex Doppler sonography. The Doppler sonography spectrum of the right hepatic vein was classified into three groups: triphasic waveform, biphasic waveform, and monophasic or flat waveform. Results: There was a statistically significant difference in the phasicity of hepatic venous flow between patients and control subjects (p < 0.001). The Doppler flow pattern in the right hepatic vein was triphasic in 28 (47.5%), biphasic in 28 (47.5%), and monophasic in 3 (5%) children with fatty liver, while it was triphasic in 43 (95.6%) and biphasic in 2 (4.4%) control subjects. There was an inverse correlation between the sonographic grade of fatty infiltration of the liver and the phasicity of hepatic venous flow (r = -0.479, p < 0.001). Conclusions: Abnormal right hepatic vein Doppler waveform, biphasic as well as monophasic, can be seen in healthy obese children with diffuse FIL.

  12. Local regulation of blood flow evaluated simultaneously by 133-xenon washout and laser Doppler flowmetry

    International Nuclear Information System (INIS)

    Engelhart, M.; Petersen, L.J.; Kristensen, J.K.

    1988-01-01

    The laser Doppler flowmeter and the 133-Xenon washout techniques of measuring cutaneous blood flow were compared for measuring the vasoconstrictor response of the hand during orthostatic maneuvres. Important discrepancies were detected for the two methods. When the hand was lowered by 40 cm a 40% decrease in blood flow was detected by the 133-Xenon method, while a 60% decrease was seen by the laser Doppler technique. Lowering the hand by 50 cm resulted in no further blood flow decrease when using the 133-Xenon method, but an 80% blood flow decrease was recorded with the laser Doppler method. A marked decrease in blood flow was recorded by the laser Doppler technique in hands that were sympathectomized or a hand that was subjected to a nerve blockade, strategies which should eliminate the orthostatic vasoconstrictor response of superficial cutaneous vessels. The 133-Xenon technique did not detect any blood flow changes in hands without sympathetic tone. We found the laser Doppler flowmetry technique unsatisfactory for measurement of blood flow changes that occur in nutritional vessels as this method measures total skin blood flow including non-capillary vessels

  13. The role of colour flow Doppler in the investigation of the salivary gland tumour

    International Nuclear Information System (INIS)

    Bradley, M.J.; Durham, L.H.; Lancer, J.M.

    2000-01-01

    AIMS: Ultrasound is a highly effective imaging technique to determine salivary gland tumours and may help to identify many benign lesions. The aim of this study is to evaluate whether colour Doppler is able to further differentiate the malignant tumour. METHODS: Fifty-six patients with salivary gland lesions were prospectively assessed using ultrasound imaging with colour flow and power Doppler. The peak systolic velocity (PSV) was measured and the pulsatility index (PI) and resistive index (RI) calculations were performed on the pulsed wave traces. The real time ultrasound morphology and the Doppler information were correlated with the histology. RESULTS: In 18 of the 56 patients, no internal colour flow or power Doppler changes could be detected. The real time ultrasound morphology diagnosed benign disease with sensitivity of 89.7% with specificity of 57.1%. The positive predictive value was 93.6%. There were no significant differences in the colour Doppler appearances in terms of vessel type or intratumour distribution which could separate benign from malignant conditions. However, there was statistical discrimination for PI and RI values (P = 0.0006, P = 0.0002, respectively). No malignant lesions were seen when the PI was less than 1.8 and RI was less than 0.8. The PSV was elevated in several cases (> 50 cm per s) but there was no statistical correlation with malignancy. CONCLUSION: The risk of malignancy increases by a third when the colour Doppler demonstrates increased intratumour vascular resistance (RI > 0.8 and PI > 1.8), with positive predictive value of 97.3% (sensitivity 75.5%, specificity 85.7%). Bradley, M.J. (2000). Clinical Radiology 55, 759-762

  14. Right Ventricular Doppler Echocardiographic Study of Indeterminate Form of Chagas Disease

    Directory of Open Access Journals (Sweden)

    Rogério Gomes Furtado

    2015-03-01

    Full Text Available Background: Patients with indeterminate form of Chagas disease/cardiac normality (ICD/CN exhibited normal electrocardiograms and chest X-rays; however, more sophisticated tests detected some degree of morphological and functional changes in the heart. Objective: To assess the prevalence of systolic and diastolic dysfunction of the right ventricle (RV in patients with ICD/CN. Methods: This was a case–control and prevalence study. Using Doppler two-dimensional echocardiography (2D, 92 patients were assessed and divided into two groups: group I (normal, n = 31 and group II (ICD/CN, n = 61. Results: The prevalence of RV systolic dysfunction in patients in groups I and II was as follows: fractional area change (0.0% versus 0.6%, mobility of the tricuspid annulus (0.0% versus 0.0%, and S-wave tissue Doppler (6.4% versus 26.0%, p = 0.016. The prevalence of global disorders such as the right myocardial performance index using tissue Doppler (16.1% versus 27.8%, p = 0.099 and pulsed Doppler (61.3% versus 68%, p = 0.141 and diastolic disorders such as abnormal relaxation (0.0% versus 6.0%, pseudonormal pattern (0.0% versus 0.0%, and restrictive pattern (0.0% versus 0.0% was not statistically different between groups. Conclusion: The prevalence of RV systolic dysfunction was estimated to be 26% (S wave velocity compared with other variables, suggesting incipient changes in RV systolic function in the ICD/CN group.

  15. Altered doppler flow patterns in cirrhosis patients: An overview

    Energy Technology Data Exchange (ETDEWEB)

    Iranpour, Pooya; Lall, Chandana; Houshyar, Roozbeh; Helmy, Mohammad; Yang, Albert; Ward, Garrett; Goodwin, Scott C. [Dept. of Radiology, University of California Irvine, Orange (United States); Choi, Joon Il [Dept. of Radiology, Seoul St. Mary' s Hospital, College of Medicine, The Catholic University of Korea, Seoul (Korea, Republic of)

    2016-01-15

    Doppler ultrasonography of the hepatic vasculature is an integral part of evaluating precirrhotic and cirrhotic patients. While the reversal of the portal venous flow is a well-recognized phenomenon, other flow patterns, although not as easily understood, may play an important role in assessing the disease status. This article discusses the different characteristic flow patterns observed from the portal vein, hepatic artery, and hepatic vein in patients with liver cirrhosis or related complications and procedures. Knowledge of these different flow patterns provides additional information that may reinforce the diagnosis of cirrhosis, help in staging, and offer prognostic information for determining the direction of therapy. Doppler ultrasonography is invaluable when liver transplantation is being considered and aids in the diagnosis of cirrhosis and portal hypertension.

  16. Role of uterine artery doppler ultrasound in predicting preeclampsia primigravida

    International Nuclear Information System (INIS)

    Awan, F.; Ullah, H.

    2016-01-01

    Objective: To find the accuracy of uterine artery diastolic notching during the second trimester of pregnancy in predicting pre-eclampsia in primigravida patients. Study Design: Descriptive cross sectional study. Place and Duration of Study: Armed Forces Institute of Radiology and Imaging (AFIRI) Rawalpindi; six months duration from 30 Nov 2012 to 31 May 2013. Material and Methods: This study included 199 primigravida women with singleton pregnancy having diastolic notch in uterine arteries between 20 to 23 weeks of gestation. All patients were examined by both grey scale and doppler ultrasonography. Uterine arteries were evaluated with doppler near the point where they crossed the external iliac arteries. The patient was included in study if the presence of diastolic notch was demonstrated. Clinical follow up in gynae and obs department continued throughout the pregnancy to see if they developed preeclampsia. The data were recorded on a previously prepared proforma and analyzed with SPSS 21. Results: The accuracy of uterine artery doppler ultrasound in identifying women who later developed preeclampsia was 48.24 percent. The frequency of pre-eclampsia with bilateral notch was significantly high in the primigravid of younger age as compare to the primigravid of the older group (p=0.001). The difference in frequency of developing pre-eclampsia with bilateral notch when compared among 20 to 21 week gestational age and 22 to 23 weeks gestational age was statistically insignificant. Conclusion: Uterine artery diastolic notching between 20 and 23 weeks of gestation is an important risk factor for developing pre-eclampsia. This doppler parameter should, therefore, be included in the risk evaluation for gestational hypertension. (author)

  17. Power Doppler ultrasonography and synovitis: correlating ultrasound imaging with histopathological findings and evaluating the performance of ultrasound equipments.

    Science.gov (United States)

    Koski, J M; Saarakkala, S; Helle, M; Hakulinen, U; Heikkinen, J O; Hermunen, H

    2006-12-01

    To examine the validity of power Doppler ultrasound imaging to identify synovitis, using histopathology as gold standard, and to assess the performance of ultrasound equipments. 44 synovial sites in small and large joints, bursae and tendon sheaths were depicted with ultrasound. A synovial biopsy was performed on the site depicted and a synovial sample was taken for histopathological evaluation. The performance of three ultrasound devices was tested using flow phantoms. A positive Doppler signal was detected in 29 of 35 (83%) of the patients with active histological inflammation. In eight additional samples, histological examination showed other pathological synovial findings and a Doppler signal was detected in five of them. No significant correlation was found between the amount of Doppler signal and histological synovitis score (r = 0.239, p = NS). The amount of subsynovial infiltration of polymorphonuclear leucocytes and surface fibrin correlated significantly with the amount of power Doppler signal: r = 0.397 (pultrasound devices differed in showing the smallest detectable flow. A negative Doppler signal does not exclude the possibility of synovitis. A positive Doppler signal in the synovium is an indicator of an active synovial inflammation in patients. A Doppler signal does not correlate with the extent of the inflammation and it can also be seen in other synovial reactions. It is important that the quality measurements of ultrasound devices are reported, because the results should be evaluated against the quality of the device used.

  18. Early complications of renal transplantation; Is duplex-Doppler US useful in the diagnosis of acute rejection. Valutazione delle complicanze precoci del trapianto renale; Qual'e' l'utilita' del Doppler-duplex nella diagnosi del rigetto acuto

    Energy Technology Data Exchange (ETDEWEB)

    Zompatori, M; Gavelli, G; Bernasconi, A; Rimondi, M R [Bologna Univ. (Italy). Ist. di Radiologia; Scolari, M P; D' Arcangelo, G L; Raimondi, C [Bologna Univ. (Italy). Cattedra di Nefrologia

    1991-01-01

    The authors studied with duplex-Doppler US28 renal transplant recipients in 31 clinically different episodes, during the early postoperative period. Morphological data were thus obtained, as well as hemodinamic information. According to the literature on the subject, a pulsatility index (PI) >1.5 was considered as abnormal. US diagnosis was retrospectively compared with final clinical diagnosis and with response to therapy. In one case, the kidney was surgically removed. We evaluated US sensitivity and specificity in the diagnosis of acute rejection with real-time US, Doppler alone and combined with duplex. A PI {>=}1.5 corresponded to acute rejection, with 60% sensitivity and 85.7% specificity. With a PI >1.8, sensitivity decreased to 50%, but specificity increased to100%. The severest changes in Doppler waveform had a bad prognostic significance. Besides poor specificity- which is so often emphasized in literature- our results chiefly demonstrated sensitivity limitations, partly corrigible with a real-time US signs, together with Doppler PI (sensitivity: 90%, specificity: 85.7%). Duplex-Doppler US, in spite of its well-known limitations, remains therefore a simple, rather reliable and non-invasive technique to study renal transplant complications. 31 Refs.

  19. Design And Analysis Of Doppler Radar-Based Vehicle Speed Detection

    Directory of Open Access Journals (Sweden)

    Su Myat Paing

    2015-08-01

    Full Text Available The most unwanted thing to happen to a road user is road accident. Most of the fatal accidents occur due to over speeding. Faster vehicles are more prone to accident than the slower one. Among the various methods for detecting speed of the vehicle object detection systems based on Radar have been replaced for about a century for various purposes like detection of aircrafts spacecraft ships navigation reading weather formations and terrain mapping. The essential feature in adaptive vehicle activated sign systems is the accurate measurement of a vehicles velocity. The velocities of the vehicles are acquired from a continuous wave Doppler radar. A very low amount of power is consumed in this system and only batteries can use to operate. The system works on the principle of Doppler Effect by detecting the Doppler shift in microwaves reflected from a moving object. Since the output of the sensor is sinusoidal wave with very small amplitude and needs to be amplified with the help of the amplifier before further processing. The purpose to calculate and display the speed on LCD is performed by the microcontroller.

  20. NAMMA NASA POLARIMETRIC DOPPLER WEATHER RADAR (NPOL) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The NAMMA NASA Polarimetric Doppler Weather Radar (NPOL) dataset used the NPOL, developed by a research team from Wallops Flight Facility, is a fully transportable...

  1. Nonlinear Suppression of Range Ambiguity in Pulse Doppler Radar

    National Research Council Canada - National Science Library

    Anderson, Jon

    2001-01-01

    ... ambiguities in Doppler and range. First introduced by Palermo in 1962 using two conjugate LFM pulses, the primary nonlinear suppression objective involves reducing range ambiguity, given the waveform is nominally unambiguous...

  2. Wind field measurement in the nonprecipitous regions surrounding storms by an airborne pulsed Doppler lidar system, appendix A

    Science.gov (United States)

    Bilbro, J. W.; Vaughan, W. W.

    1980-01-01

    Coherent Doppler lidar appears to hold great promise in contributing to the basic store of knowledge concerning flow field characteristics in the nonprecipitous regions surrounding severe storms. The Doppler lidar, through its ability to measure clear air returns, augments the conventional Doppler radar system, which is most useful in the precipitous regions of the storm. A brief description of the Doppler lidar severe storm measurement system is provided along with the technique to be used in performing the flow field measurements. The application of the lidar is addressed, and the planned measurement program is outlined.

  3. Spectral fine structure effects on material and doppler reactivity worth

    International Nuclear Information System (INIS)

    Greenspan, E.; Karni, Y.

    1975-01-01

    New formulations concerning the fine structure effects on the reactivity worth of resonances are developed and conclusions are derived following the extension to more general types of perturbations which include: the removal of resonance material at finite temperatures and the temperature variation of part of the resonance material. It is concluded that the flux method can overpredict the reactivity worth of resonance materials more than anticipated. Calculations on the Doppler worth were carried out; the results can be useful for asessing the contribution of the fine structure effects to the large discrepancy that exists between the calculated and measured small sample Doppler worths. (B.G.)

  4. Using microwave Doppler radar in automated manufacturing applications

    Science.gov (United States)

    Smith, Gregory C.

    Since the beginning of the Industrial Revolution, manufacturers worldwide have used automation to improve productivity, gain market share, and meet growing or changing consumer demand for manufactured products. To stimulate further industrial productivity, manufacturers need more advanced automation technologies: "smart" part handling systems, automated assembly machines, CNC machine tools, and industrial robots that use new sensor technologies, advanced control systems, and intelligent decision-making algorithms to "see," "hear," "feel," and "think" at the levels needed to handle complex manufacturing tasks without human intervention. The investigator's dissertation offers three methods that could help make "smart" CNC machine tools and industrial robots possible: (1) A method for detecting acoustic emission using a microwave Doppler radar detector, (2) A method for detecting tool wear on a CNC lathe using a Doppler radar detector, and (3) An online non-contact method for detecting industrial robot position errors using a microwave Doppler radar motion detector. The dissertation studies indicate that microwave Doppler radar could be quite useful in automated manufacturing applications. In particular, the methods developed may help solve two difficult problems that hinder further progress in automating manufacturing processes: (1) Automating metal-cutting operations on CNC machine tools by providing a reliable non-contact method for detecting tool wear, and (2) Fully automating robotic manufacturing tasks by providing a reliable low-cost non-contact method for detecting on-line position errors. In addition, the studies offer a general non-contact method for detecting acoustic emission that may be useful in many other manufacturing and non-manufacturing areas, as well (e.g., monitoring and nondestructively testing structures, materials, manufacturing processes, and devices). By advancing the state of the art in manufacturing automation, the studies may help

  5. Flow Profile Study using miniature Laser-Doppler velocimetry

    NARCIS (Netherlands)

    Booij, W.E.; Booij, W.E.; de Jongh, A.; de Mul, F.F.M.

    1995-01-01

    We present a physics experiment, in which laser - Doppler velocimetry is used to make first - year university physics students realize that the idealized solutions offered by standard text books seldom are applicable without corrections, which often are numerical. This is demonstrated by carefully

  6. Cloud fraction and cloud base measurements from scanning Doppler lidar during WFIP-2

    Science.gov (United States)

    Bonin, T.; Long, C.; Lantz, K. O.; Choukulkar, A.; Pichugina, Y. L.; McCarty, B.; Banta, R. M.; Brewer, A.; Marquis, M.

    2017-12-01

    The second Wind Forecast Improvement Project (WFIP-2) consisted of an 18-month field deployment of a variety of instrumentation with the principle objective of validating and improving NWP forecasts for wind energy applications in complex terrain. As a part of the set of instrumentation, several scanning Doppler lidars were installed across the study domain to primarily measure profiles of the mean wind and turbulence at high-resolution within the planetary boundary layer. In addition to these measurements, Doppler lidar observations can be used to directly quantify the cloud fraction and cloud base, since clouds appear as a high backscatter return. These supplementary measurements of clouds can then be used to validate cloud cover and other properties in NWP output. Herein, statistics of the cloud fraction and cloud base height from the duration of WFIP-2 are presented. Additionally, these cloud fraction estimates from Doppler lidar are compared with similar measurements from a Total Sky Imager and Radiative Flux Analysis (RadFlux) retrievals at the Wasco site. During mostly cloudy to overcast conditions, estimates of the cloud radiating temperature from the RadFlux methodology are also compared with Doppler lidar measured cloud base height.

  7. Development and validation of the fast doppler broadening module coupled within RMC code

    International Nuclear Information System (INIS)

    Yu Jiankai; Liang Jin'gang; Yu Ganglin; Wang Kan

    2015-01-01

    It is one of the efficient approach to reduce the memory consumption in Monte Carlo based reactor physical simulations by using the On-the-fly Doppler broadening for temperature dependent nuclear cross sections. RXSP is a nuclear cross sections processing code being developed by REAL team in Department of Engineering Physics in Tsinghua University, which has an excellent performance in Doppler broadening the temperature dependent continuous energy neutron cross sections. To meet the dual requirements of both accuracy and efficiency during the Monte Carlo simulations with many materials and many temperatures in it, this work enables the capability of on-the-fly pre-Doppler broadening cross sections during the neutron transport by coupling the Fast Doppler Broaden module in RXSP code embedded in the RMC code also being developed by REAL team in Tsinghua University. Additionally, the original OpenMP-based parallelism has been successfully converted into the MPI-based framework, being fully compatible with neutron transport in RMC code, which has achieved a vast parallel efficiency improvement. This work also provides a flexible approach to solve Monte Carlo based full core depletion calculation with many temperatures feedback in many isotopes. (author)

  8. Radar Micro-Doppler classification of Mini-UAVs

    NARCIS (Netherlands)

    Harmanny, R.L.A.; Prémel-Cabic, G.; Wit, J.J.M.

    2015-01-01

    The radar micro-Doppler signature of a target depends on its micro-motion, i.e., the motion of parts of a target relative to the motion of the target as a whole. These micro-motions are very characteristic considering different target classes, e.g., the slow pendulum-like motion of a bird’s wings

  9. Usefulness of color and pulsed Doppler's in the evaluation of surgical portosystemic shunts in pediatric patients

    International Nuclear Information System (INIS)

    Berrocal, T.; Prieto, C.; Cortes, P.; Rodriguez, R.; Pastor, I.

    2003-01-01

    Portosystemic shunts are performed to relieve symptomatic portal hypertension symptomatic or removal pressure in hepatic vascularisation in patients with Budd-Chiari's syndrome. Most surgical portosystemic shunts can be suitably studied by means of ultrasound scan complemented by color and pulsed Dopplers, proved one understands the hemodynamics of the surgical procedures involved. This article demonstrates the usefulness and limitations of the ultrasound scan Duplex Doppler in the evaluation of portosystemic shunts performed on pediatric patients. Pulsed Doppler provides information regarding the nature and direction of blood flow. Color doppler is capable of directly revealing the shunt and, in most cases, permits the anastomosis to be located. The types of shunts that appear include proximal and distal spleno-renal, portocaval and mesocaval. Types of vascular connections are illustrated,s well as expected post-surgical blood flow direction in affected vessels. The ultrasound scanning technique is discussed, as well as the criteria for determining vascular permeability. Also highlighted are the advantages, limitations and diagnostic difficulties associated with the different forms of Doppler. (Author) 17 refs

  10. Planetary Radio Interferometry and Doppler Experiment (PRIDE) for Planetary Atmospheric Studies

    Science.gov (United States)

    Bocanegra Bahamon, Tatiana; Cimo, Giuseppe; Duev, Dmitry; Gurvits, Leonid; Molera Calves, Guifre; Pogrebenko, Sergei

    2015-04-01

    The Planetary Radio Interferometry and Doppler Experiment (PRIDE) is a technique that allows the determination of the radial velocity and lateral coordinates of planetary spacecraft with very high accuracy (Duev, 2012). The setup of the experiment consists of several ground stations from the European VLBI Network (EVN) located around the globe, which simultaneously perform Doppler tracking of a spacecraft carrier radio signal, and are subsequently processed in a VLBI-style in phase referencing mode. Because of the accurate examination of the changes in phase and amplitude of the radio signal propagating from the spacecraft to the multiple stations on Earth, the PRIDE technique can be used for several fields of planetary research, among which planetary atmospheric studies, gravimetry and ultra-precise celestial mechanics of planetary systems. In the study at hand the application of this technique for planetary atmospheric investigations is demonstrated. As a test case, radio occultation experiments were conducted with PRIDE having as target ESA's Venus Express, during different observing sessions with multiple ground stations in April 2012 and March 2014. Once each of the stations conducts the observation, the raw data is delivered to the correlation center at the Joint Institute for VLBI in Europe (JIVE) located in the Netherlands. The signals are processed with a high spectral resolution and phase detection software package from which Doppler observables of each station are derived. Subsequently the Doppler corrected signals are correlated to derive the VLBI observables. These two sets of observables are used for precise orbit determination. The reconstructed orbit along with the Doppler observables are used as input for the radio occultation processing software, which consists of mainly two modules, the geometrical optics module and the ray tracing inversion module, from which vertical density profiles, and subsequently, temperature and pressure profiles of Venus

  11. Vascular response to ischemia in the feet of falanga torture victims and normal controls--color and spectral Doppler findings

    DEFF Research Database (Denmark)

    Torp-Pedersen, Søren; Amris, Kirstine; Holm, Christian Cato

    2009-01-01

    to controls. On color Doppler this would be seen as less color after ischemia and on spectral Doppler as elevated resistive index (RI). METHODS: Ten male torture victims from the Middle East and nine age, sex and ethnically matched controls underwent Doppler examination of the abductor hallucis and flexor...... digitorum brevis muscles before and after two minutes ischemia induced with a pressure cuff over the malleoli. The color Doppler findings were quantified with the color fraction (CF) before and after ischemia. On spectral Doppler the resistive index was measured once before and three consecutive times after....... However, the trend in RI still supports the hypothesis. The negative findings may be due to inadequate design where the CF and RI were measured in one setting, perhaps resulting in both methods being applied imperfectly. The response to ischemia seems short-lived and we suggest that the Doppler methods...

  12. Color Doppler Ultrasonographic Features of Hashimoto's Thyroiditis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Joo Hyuk; Kim, Mie Young; Rho, Eun Jin; Yi, Jeong Geun; Han, Chun Hwan [Kangnam General Hospital Public Corporation, Seoul (Korea, Republic of); Hwang, Hee Yong [Choong Ang Gil Hospital, Incheon (Korea, Republic of)

    1995-06-15

    Color Doppler ultrasonographic(US) features of 28 patients with Hashimato's thyroiditis were evaluated with regard to echo and color-flow patterns. Correlation of color-flow pattern with thyroid function was performed. All 28 patients showed varying degrees of diffuse enlargement of the thyroid gland and a heterogeneous echo pattern.Color-flow pattern of increased blood flow. Low to moderate, focally increased blood flow was seen in 26 patients(92.8%). Of these 26 patients, 24 patients showed subclinical hypothyroidism or euthyroidism. Two patients who showed hyperthyroidism showed several pieces of focally increased color flow, Which was noted during both systole and diastole. Diffuse, multifocal color-flow throughout thyroid gland was seen in two patients with Hashimato's thyroiditis: one with clinical hypothyroidism and the other with subclinical hypothyroidism. Even though Hashimoto's thyroiditis showed variable color-flow patterns, we believe that heterogenous parenchymal echopattern with low or moderately increased flow is a rather characteristic feature of Hashimoto's thyroiditis, and we suggest that color Doppler US provides additional information for evaluation of Hashimoto's thyroiditis

  13. Color Doppler Ultrasonographic Features of Hashimoto's Thyroiditis

    International Nuclear Information System (INIS)

    Lee, Joo Hyuk; Kim, Mie Young; Rho, Eun Jin; Yi, Jeong Geun; Han, Chun Hwan; Hwang, Hee Yong

    1995-01-01

    Color Doppler ultrasonographic(US) features of 28 patients with Hashimato's thyroiditis were evaluated with regard to echo and color-flow patterns. Correlation of color-flow pattern with thyroid function was performed. All 28 patients showed varying degrees of diffuse enlargement of the thyroid gland and a heterogeneous echo pattern.Color-flow pattern of increased blood flow. Low to moderate, focally increased blood flow was seen in 26 patients(92.8%). Of these 26 patients, 24 patients showed subclinical hypothyroidism or euthyroidism. Two patients who showed hyperthyroidism showed several pieces of focally increased color flow, Which was noted during both systole and diastole. Diffuse, multifocal color-flow throughout thyroid gland was seen in two patients with Hashimato's thyroiditis: one with clinical hypothyroidism and the other with subclinical hypothyroidism. Even though Hashimoto's thyroiditis showed variable color-flow patterns, we believe that heterogenous parenchymal echopattern with low or moderately increased flow is a rather characteristic feature of Hashimoto's thyroiditis, and we suggest that color Doppler US provides additional information for evaluation of Hashimoto's thyroiditis

  14. The role of colour Doppler sonography in the diagnosis of lower limb Klippel–Trénaunay syndrome

    International Nuclear Information System (INIS)

    Qi, H.T.; Wang, X.M.; Zhang, X.D.; Zhang, M.H.; Li, C.M.; Bao, S.G.; Yuan, H.

    2013-01-01

    Aim: To investigate the accuracy of colour Doppler sonography as compared to phlebography in patients with Klippel-Trénaunay syndrome (KTS). Materials and methods: From September 2004 to May 2012, 59 consecutive patients seen in Shandong medical imaging research institute with a clinical suggestion of KTS were included. Thirty-four were female and 25 were male, with a mean age of 28.4 years. Colour Doppler sonography was used to assess the lower limb veins. The main sonographic criteria for a positive diagnosis were visualization of the lateral vein or sciatic vein, capillary haemangioma, and abnormality of the deep veins. These data were compared with phlebography findings. The κ statistic was used to determine the level of agreement. The sensitivity, specificity, positive and negative predictive values, and accuracy of colour Doppler sonography as a diagnostic test were assessed. Results: Colour Doppler sonography findings were positive in 21 of 59 patients with a clinical suggestion of KTS. The diagnosis was confirmed using phlebography in 22 patients. There were two false-positive results and one false-negative result by colour Doppler sonography. The κ-value was 0.892. Sensitivity, specificity, positive and negative predictive values, and accuracy for colour Doppler sonography were 95.4, 94.6, 91.3, 97.2, and 94.9%, respectively. Conclusion: Colour Doppler sonography is an accurate, reliable, and non-invasive investigation in the assessment of patients with suspected KTS

  15. Central venous cannulation: are routine chest radiographs necessary after B-mode and colour Doppler sonography check?

    International Nuclear Information System (INIS)

    Lanza, Cecilia; Fabrizzi, Giancarlo; Russo, Marco

    2006-01-01

    After the insertion of a central venous catheter, a chest radiograph is usually obtained to ensure correct positioning of the catheter tip. To determine in a paediatric population whether B-mode and colour Doppler sonography after central venous access is useful to evaluate catheter position, thus obviating the need for a postprocedural radiograph. A prospective study of 107 consecutive central venous access procedures placed in a paediatric intensive care unit was performed. At the end of the procedure, B-mode and colour Doppler sonography were used to assess catheter position and check for complications. A postprocedural chest radiograph was obtained in all patients. In 96 patients postprocedural B-mode and colour Doppler sonography showed colour Doppler signals within the vena cava. Among the 11 patients predicted to have a potential complication, there was one pneumothorax and ten malpositions. Chest radiography showed a total of 13 complications - 1 pneumothorax and 12 malpositions. The concordance between colour Doppler sonography and chest radiography was 98.1% in the detection of catheter position; sonography had a sensitivity of 84.6% and a specificity of 100%. The close concordance between B-mode and colour Doppler sonography and chest radiography justifies the more frequent use of sonography to evaluate catheter position because ionizing radiation is eliminated. Chest radiography may then be performed only when there is suspected inappropriate catheter tip position after sonography. (orig.)

  16. Evaluation of the activity of synovitis in patients with rheumatoid arthritis: Value of power Doppler ultrasonography

    International Nuclear Information System (INIS)

    Ahn, Joong Mo; Lim, Hyo Keun; Kim, Seung Hoon; Kim, Sung Hyun; Koh, Eun Mi; Kim, Jin Seok; Cha, Hoon Suk

    2001-01-01

    To correlate the grades on power Doppler ultrasonography with clinical disease activity indices and acute phase reactant values for assessing the activity of synovitis in patients with rheumatoid arthritis. Twenty patients with rheumatoid arthritis diagnosed on the basis of American College of power Doppler ultrasonography. Two experienced radiologists evaluated, in consensus, the power Doppler signals as follows: grade I=no flow or minimal flow, grade 2=mild flow, grade 3=moderate flow and grade 4= marked flow. The clinical disease activity indices consisted of the counts of tender joints and swollen joints, patient's assessment of pain, patient's global assessment of disease activity, physician's globe assessment of disease activity and patient's assessment of physical function. Acute-phase reactants included CRP and ESR. The grades on power Doppler ultrasonography were correlated with clinical disease activity indices as well as acute-phases reactant values by a use of Spearman rank correlation coefficient. The grades on power Doppler ultrasonography showed a statistically significant correlation with tender joint count (rs=.835; p<.05), swollen joint count (rs=.833; p<.05), physician's global assessment of disease activity (rs=.857; p<.05), CRP (rs=.838; P<.05) and ESR (rs=.838; p<.05). The power Doppler ultrasonography is an useful diagnostic modality for assessing the activity of synovitis in patients with rheumatoid arthritis.

  17. Performance bounds on micro-Doppler estimation and adaptive waveform design using OFDM signals

    Science.gov (United States)

    Sen, Satyabrata; Barhen, Jacob; Glover, Charles W.

    2014-05-01

    We analyze the performance of a wideband orthogonal frequency division multiplexing (OFDM) signal in estimating the micro-Doppler frequency of a target having multiple rotating scatterers (e.g., rotor blades of a helicopter, propellers of a submarine). The presence of rotating scatterers introduces Doppler frequency modulation in the received signal by generating sidebands about the transmitted frequencies. This is called the micro-Doppler effects. The use of a frequency-diverse OFDM signal in this context enables us to independently analyze the micro-Doppler characteristics with respect to a set of orthogonal subcarrier frequencies. Therefore, to characterize the accuracy of micro-Doppler frequency estimation, we compute the Craḿer-Rao Bound (CRB) on the angular-velocity estimate of the target while considering the scatterer responses as deterministic but unknown nuisance parameters. Additionally, to improve the accuracy of the estimation procedure, we formulate and solve an optimization problem by minimizing the CRB on the angular-velocity estimate with respect to the transmitting OFDM spectral coefficients. We present several numerical examples to demonstrate the CRB variations at different values of the signal-to-noise ratio (SNR) and the number of OFDM subcarriers. The CRB values not only decrease with the increase in the SNR values, but also reduce as we increase the number of subcarriers implying the significance of frequency-diverse OFDM waveforms. The improvement in estimation accuracy due to the adaptive waveform design is also numerically analyzed. Interestingly, we find that the relative decrease in the CRBs on the angular-velocity estimate is more pronounced for larger number of OFDM subcarriers.

  18. Performance Bounds on Micro-Doppler Estimation and Adaptive Waveform Design Using OFDM Signals

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Satyabrata [ORNL; Barhen, Jacob [ORNL; Glover, Charles Wayne [ORNL

    2014-01-01

    We analyze the performance of a wideband orthogonal frequency division multiplexing (OFDM) signal in estimating the micro-Doppler frequency of a target having multiple rotating scatterers (e.g., rotor blades of a helicopter, propellers of a submarine). The presence of rotating scatterers introduces Doppler frequency modulation in the received signal by generating sidebands about the transmitted frequencies. This is called the micro-Doppler effects. The use of a frequency-diverse OFDM signal in this context enables us to independently analyze the micro-Doppler characteristics with respect to a set of orthogonal subcarrier frequencies. Therefore, to characterize the accuracy of micro-Doppler frequency estimation, we compute the Cram er-Rao Bound (CRB) on the angular-velocity estimate of the target while considering the scatterer responses as deterministic but unknown nuisance parameters. Additionally, to improve the accuracy of the estimation procedure, we formulate and solve an optimization problem by minimizing the CRB on the angular-velocity estimate with respect to the transmitting OFDM spectral coefficients. We present several numerical examples to demonstrate the CRB variations at different values of the signal-to-noise ratio (SNR) and the number of OFDM subcarriers. The CRB values not only decrease with the increase in the SNR values, but also reduce as we increase the number of subcarriers implying the significance of frequency-diverse OFDM waveforms. The improvement in estimation accuracy due to the adaptive waveform design is also numerically analyzed. Interestingly, we find that the relative decrease in the CRBs on the angular-velocity estimate is more pronounced for larger number of OFDM subcarriers.

  19. Analytical Model of Doppler Spectra of Light Backscattered from Rotating Convex Bodies of Revolution in the Global Cartesian Coordinate System

    International Nuclear Information System (INIS)

    Yan-Jun, Gong; Zhen-Sen, Wu; Jia-Ji, Wu

    2009-01-01

    We present an analytical model of Doppler spectra in backscattering from arbitrary rough convex bodies of revolution rotating around their axes in the global Cartesian coordinate system. This analytical model is applied to analyse Doppler spectra in backscatter from two cones and two cylinders, as well as two ellipsoids of revolution. We numerically analyse the influences of attitude and geometry size of objects on Doppler spectra. The analytical model can give contribution of the surface roughness, attitude and geometry size of convex bodies of revolution to Doppler spectra and may contribute to laser Doppler velocimetry as well as ladar applications

  20. Resolution and Micro-Doppler Effect in Bi-ISAR System (in English

    Directory of Open Access Journals (Sweden)

    Deng Dong-hu

    2013-06-01

    Full Text Available Compared to the monostatic radar, bistatic radar has many special characteristics because of its spatial complexity. Bistatic Inverse Synthetic Aperture Radar (Bi-ISAR can be employed as a radar imaging tool for obtaining non-cooperative target images. In this study, we first analyze the range and azimuth resolution of a Bi-ISAR system. To analyze this azimuth resolution and its spatial-variety characteristic, a definition called con-Doppler bandwidth is introduced, which helps overcome the difficulty of the target’s viewing angle diversity calculation. Then, a detailed investigation is conducted to study the micro-Doppler effect caused by the vibration and the rotation of the target in the Bi-ISAR system. By comparing the difference in the micro-Doppler effect between the Bi-ISAR system and the Mono-ISAR system, we modify the extended Hough transform to extract the real micro-motion features of the targets. Finally, we provide some simulation results to validate the theoretical derivation and to illustrate the effectiveness of the proposed method.

  1. [Vascular complications following kidney transplant: the role of color-Doppler imaging].

    Science.gov (United States)

    Granata, Antonio; Floccari, Fulvio; Lentini, Paolo; Vittoria, Salvatore; Di Pietro, Fabio; Zamboli, Pasquale; Fiorini, Fulvio; Fatuzzo, Pasquale

    2012-01-01

    The progressive decline in the incidence of graft rejection has made urological, surgical, parenchymal and vascular complications of kidney transplant more frequent. The latter, although accounting for only 5-10% of all post-transplant complications, are a frequent cause of graft loss. Ultrasonography, both in B-mode and with Doppler ultrasound, is an important diagnostic tool in case of clinical conditions which might impair kidney function. Even though ultrasonography is considered fundamental in the diagnosis of parenchymal and surgical complications of the transplanted kidney, its role is not fully understood in case of vascular complications of the graft. The specificity of Doppler ultrasound is very important in case of stenosis of the transplanted renal artery, pseudoaneurysms, arteriovenous fistulas, and thrombosis with complete or partial artery or vein occlusion. Doppler and color determinations present high diagnostic accuracy, which is higher in case of successive measurements performed during the follow-up of the graft. Modern techniques including contrast-enhanced ultrasound increase the diagnostic power of ultrasonography in case of vascular complications of the transplanted kidney, planted kidney.

  2. Doppler-Zeeman Mapping of the Rapidly Rotating Magnetic CP Star HD37776

    Science.gov (United States)

    Khokhlova, V. L.; Vasilchenko, D. V.; Stepanov, V. V.; Romanyuk, I. I.

    2000-03-01

    We present the results of our analysis of magnetic-field configuration and abundance anomalies on the surface of the rapidly rotating, chemically peculiar helium-strong variable B2 V star HD37776 with unresolved Zeeman components of spectral lines. Simultaneous inversion of the observed Stokes I and V profiles, which realizes the method of Doppler-Zeeman mapping (Vasilchenko et al. 1996), has been applied for the first time. Spectroscopic observations were carried out with the Main stellar spectrograph of the 6-m Special Astrophysical Observatory telescope equipped with a Zeeman analyzer and a CCD array, which allowed spectra in right- and left-hand circularly polarized light to be taken simultaneously at a signal-to-noise ratio S/N > 200 (Romanyuk et al. 1999). The profile width of winged spectral lines (reaching 5 A) is determined by Zeeman line splitting; however, the observed Zeeman components are blurred and unresolved because of the rapid stellar rotation. When solving the inverse problem, we sought for the magnetic-field configuration in the form of a combination of arbitrarily oriented dipole, quadrupole, and octupole placed at the stellar center. The observed Stokes I and V profiles for eight spectral lines of He, OII, AlIII, SiIII, and FeIII averaged over the visible stellar surface were used as input data. We constructed a model of the magnetic field from the condition of coincidence of magnetic maps obtained from different lines of different chemical elements and from the condition of a minimum profile residual. This model is a combination of centered coaxial dipole and quadrupole with the dominant quadrupole component at 30 deg < i < 50 deg, beta = 40 deg, and a maximum surface field strength H_s = 60 kG. A comparison of our abundance maps with the field configuration shows that the He concentration is at a maximum in the regions of maximum radial field, while the maximum concentrations of O, Al, Si, and Fe coincide with the regions of maximum

  3. Pulsed and Tissue Doppler Echocardiographic Changes in Patients with Thalassemia Major

    Directory of Open Access Journals (Sweden)

    Taysir S. Garadah

    2010-01-01

    Full Text Available Background Doppler echocardiographic studies of left ventricle (LV systolic and diastolic function in patients with β-Thalassemia Major (β-TM had shown different patterns of systolic and diastolic dysfunction. Aim This cross-sectional study was designed to study the LV systolic and diastolic function in patients with β-TM using Pulsed Doppler (PD and Tissue Doppler (TD echocardiography. Methods All patients were evaluated clinically and by echocardiography, The study included patients with β-TM (n = 38, age 15.7 ± 8.9 years compared with an age-matched control group (n = 38, age 15.9 ± 8.9 years. The pulse Doppler indices were normalized for age and heart rate. Results Compared with control patients, M-Mode showed that patients with β-TM have thicker LV septal wall index (0.659 ± 0.23 vs. 0.446 ± 0.219 cm, P ≤ 0.001, posterior wall index (0.659 ± 0.235 vs. 0.437 ± 0.214 cm, P ≤ 0.01, and larger LVEDD index is (3.99 ± 0.48 vs. 2.170 ± 0.57 mm. P = 0.035. Pulsed Doppler showed high LV trans-mitral E wave velocity (70.818 ± 10.139 vs. 57.532 ± 10.139, p = 0.027 and E/A ratio (1.54 vs. 1.23, P ≤ 0.01. The duration of Deceleration time (DT and isovolumic relaxation time (IVRT were significantly shorter in patients with β-TM (150.234 ± 20.0.23 vs. 167.123 ± 19.143 msec, P ≤ 0.01 and (60.647 ± 6.77 vs. 75.474 ± 5.83 msec, P ≤ 0.001, respectively. The ratio of transmitral E wave velocity to the tissue Doppler E wave at the basal septal mitral annulus E/Em – was significantly higher in β-TM group (14.024 ± 2.29 vs. 12.132 ± 1.82, P ≤ 0.01. The Tissue Doppler systolic velocity (Sm and the early diastolic velocity (Em were significantly lower in β-TM group compared to control (4.31 ± 1.2 cm/s vs. 6.95 ± 2.1, P ≤ 0.01 and 4.31 ± 2.7 cm/s vs. 5.82 ± 2.5, P ≤ 0.01 respectively. The tricuspid valve velocity was significantly higher than controls (2.993 ± 0.569 vs. 1.93 ± 0.471 m/sec, respectively, P ≤ 0

  4. Challenges in noise removal from Doppler spectra acquired by a continuous-wave lidar

    DEFF Research Database (Denmark)

    Angelou, Nikolas; Foroughi Abari, Farzad; Mann, Jakob

    2012-01-01

    are presented. A method for determining the background noise spectrum without interrupting the transmission of the laser beam is described. Moreover, the dependency between the determination of the threshold of a Doppler spectrum with low signal-to-noise ratios and the characteristics of the wind flow......This paper is focused on the required post processing of Doppler spectra, acquired from a continuous-wave coherent lidar at high sampling rates (400 Hz) and under rapid scanning of the laser beam. In particular, the necessary steps followed for extracting the wind speed from such Doppler spectra...... are investigated and a systematic approach for removing the noise is outlined. The suggested post processing procedures are applied to two sample time series acquired by a short-range WindScanner during one second each....

  5. Color doppler findings of gastric varices compared with findings on computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Takahiro; Yamazaki, Katsu; Toyota, Jouji; Karino, Yoshiyasu; Ohmura, Takumi; Suga, Toshihiro [Sapporo Kosei General Hospital (Japan)

    2002-08-01

    The aim of this study was to evaluate the hemodynamics of gastric varices. We evaluated the detection rates of gastric varices, inflowing vessels to gastric varices, and outflowing vessels from gastric varices in 24 patients with gastric varices, using color Doppler sonography, and compared these findings with computed tomography findings. Eighteen patients had F2-type varices and 6 had F3-type, classified according to the Japanese Research Society for Portal Hypertension. Fourteen patients had fundal varices, and 10 had cardiac and fundal varices. The detection rates of collateral veins using color Doppler sonography were as follows: gastric varices were detected in all 24 patients (100%); inflowing vessels, in 21 of the 24 patients (87.5%); and outflowing vessels, in 18 of the 24 patients (75.0%). The detection rates of collateral veins, using computed tomography, were: gastric varices were detected in all 24 patients (100%); inflowing vessels, in all 24 patients (100%); and outflowing vessles, in 21 of the 24 patients (87.5%). The color Doppler findings agreed perfectly with the computed tomography findings in 13 of the 24 patients (54.2%). Although color Doppler sonography is a useful, noninvasive modality for evaluating the hemodynamics of gastric varices, it falls short in visualizing the detailed hemodynamics of the inflowing and outflowing vessels of gastric varices in half of the patients when compared with computed tomography. (author)

  6. Parametric Investigation of Laser Doppler Microphones

    Science.gov (United States)

    Daoud, M.; Naguib, A.

    2002-11-01

    The concept of a Laser Doppler Microphone (LDM) is based on utilizing the Doppler frequency shift of a focused laser beam to measure the unsteady velocity of the center point of a flexible polymer diaphragm that is mounted on top of a hole and subjected to the unsteady pressure. Time integration of the velocity signal yields a time series of the diaphragm displacement, which can be converted to pressure from knowledge of the sensor's deflection sensitivity. In our APS/DFD presentation last year, the stringent frequency resolution requirement of these new sensors and methods to meet this requirement were discussed. Here, the dependence of the sensor characteristics (sensitivity, bandwidth, and noise floor) on various significant parameters is investigated in detail by calibrating the sensor in a plane wave tube in the frequency range of 50 - 5000 Hz. Parameters investigated include sensor diaphragm material and thickness, sensor size, damping of the diaphragm motion and laser beam spot size. The results shed light on the operating limits of the new sensor and demonstrate its ability to conduct high-spatial-resolution measurements in typical high-Reynolds-number test facilities. Moreover, calibrated LDM sensors were used to conduct measurements in a separating/reattaching flow and the results are compared to classical electret-type microphones with a similar sensing diameter.

  7. Angiosonography in suspicious breast lesions with non-diagnostic FNAC: comparison with power Doppler US.

    Science.gov (United States)

    Caumo, F; Carbognin, G; Casarin, A; Pinali, L; Vasori, S; D'Onofrio, M; Pozzi Mucelli, R

    2006-02-01

    The purpose of this study was to evaluate the accuracy of angiosonography in comparison with colour Doppler ultrasound (US) in the discrimination of suspicious breast lesions with nondiagnostic fine-needle aspiration cytology (FNAC). Pre-operative Power Doppler US and angiosonography were prospectively performed in 20 suspicious breast lesions with non-diagnostic FNAC. A second-generation US contrast agent was utilised with a high-frequency transducer and a contrast-specific algorithm (low acoustic pressure CnTI). The enhancement characteristics of all lesions were analysed using qualitative and quantitative parameters obtained from time-intensity curves with the different imaging modalities. The final diagnosis was confirmed at pathology in all cases. Microvessel density (MVD) was assessed in the surgical specimen using CD34. The correct assessment of biological behaviour was achieved in all cases by angiosonography (sensitivity of 100%; specificity of 91%) and colour Doppler US (45% sensitivity; 78% specificity). MVD correlated with the biological behaviour. Angiosonography is more accurate than colour Doppler US in the correct assessment of biological behaviour of suspicious breast lesions.

  8. An improvement of wind velocity estimation from radar Doppler spectra in the upper mesosphere

    Directory of Open Access Journals (Sweden)

    S. Takeda

    2001-08-01

    Full Text Available We have developed a new parameter estimation method for Doppler wind spectra in the mesosphere observed with an MST radar such as the MU radar in the DBS (Doppler Beam Swinging mode. Off-line incoherent integration of the Doppler spectra is carried out with a new algorithm excluding contamination by strong meteor echoes. At the same time, initial values on a least square fitting of the Gaussian function are derived using a larger number of integration of the spectra for a longer time and for multiple heights. As a result, a significant improvement has been achieved with the probability of a successful fitting and parameter estimation above 80 km. The top height for the wind estimation has been improved to around 95 km. A comparison between the MU radar and the High Resolution Doppler Imager (HRDI on the UARS satellite is shown and the capability of the new method for a validation of a future satellite mission is suggested.Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics – Radio science (remote sensing; signal processing

  9. The PARAFAC-MUSIC Algorithm for DOA Estimation with Doppler Frequency in a MIMO Radar System

    Directory of Open Access Journals (Sweden)

    Nan Wang

    2014-01-01

    Full Text Available The PARAFAC-MUSIC algorithm is proposed to estimate the direction-of-arrival (DOA of the targets with Doppler frequency in a monostatic MIMO radar system in this paper. To estimate the Doppler frequency, the PARAFAC (parallel factor algorithm is firstly utilized in the proposed algorithm, and after the compensation of Doppler frequency, MUSIC (multiple signal classification algorithm is applied to estimate the DOA. By these two steps, the DOA of moving targets can be estimated successfully. Simulation results show that the proposed PARAFAC-MUSIC algorithm has a higher accuracy than the PARAFAC algorithm and the MUSIC algorithm in DOA estimation.

  10. Evaluation of cutaneous blood flow responses by 133Xe washout and a laser-Doppler flowmeter

    International Nuclear Information System (INIS)

    Engelhart, M.; Kristensen, J.K.

    1983-01-01

    A new method for noninvasive measurement of cutaneous blood flow is laser-Doppler flowmetry. The technique is based on the fact that laser light is back-scattered from the moving red blood cells, with Doppler-shifted frequencies; these impulses lead to photodetectors and are converted to flow signals. In this work we used a new system with a low noise level. Comparison was made between this technique and the atraumatic epicutaneous 133 Xe technique for measurement of cutaneous blood flow during reactive hyperemia and orthostatic pressure changes. The laser-Doppler flowmeter seems to measure blood flow in capillaries as well as in arteriovenous anastomoses, while the 133 Xe method probably measures only capillary flow. A calibration of the laser-Doppler method against the 133 Xe method would appear to be impossible in skin areas where arteriovenous anastomoses are present. The changes in blood flow during reactive hyperemia, orthostatic pressure changes, and venous stasis were found to be parallel as measured by the two methods in skin areas without shunt vessels. The laser-Doppler flowmeter would appear to be a useful supplement to the 133Xe washout method in cutaneous vascular physiology, but it is important to keep in mind that different parameters may be measured

  11. Maternal hemodynamics, fetal biometry and Dopplers in pregnancies followed up for suspected fetal growth restriction.

    Science.gov (United States)

    Roberts, Llinos A; Ling, Hua Zen; Poon, Liona; Nicolaides, Kypros H; Kametas, Nikos A

    2018-04-01

    To assess whether in a cohort of patients with small for gestational age (SGA) foetuses with estimated fetal weight ≤10 th percentile, maternal hemodynamics, fetal biometry and Dopplers at presentation, can predict the subsequent development of abnormal fetal Dopplers or delivery with birthweight Cheetah), mean arterial pressure, fetal biometry, umbilical artery (UA), middle cerebral artery (MCA) and uterine artery (UT) pulsatility index (PI) and the deepest vertical pool (DVP) of amniotic fluid. Z-scores of these variables were calculated based on reported reference ranges and the values were compared between those with evidence of abnormal fetal Dopplers at presentation (group 1), those that developed abnormal Dopplers in subsequent visits (group 2) and those who did not develop abnormal Dopplers throughout pregnancy (group 3). Abnormal fetal Dopplers were defined as UAPI >95 th percentile, or MCA PI <5 th percentile. Differences in measured variables at presentation were also compared between pregnancies delivering a baby with birthweight <3 rd and ≥3 rd percentile. Multivariate logistic regression analysis was used to determine significant predictors of birthweight <3 rd percentile and evolution from normal fetal Dopplers to abnormal fetal Dopplers in groups 2 and 3. In the study population 14 (16%) cases were in group 1, 19 (22%) in group 2 and 53 (62%) in group 3. The birthweight was <3 rd percentile in 39 (45%) cases and ≥3 rd percentile in 47 (55%). In the study groups, compared to normal populations, there was decreased cardiac output and stroke volume and increased peripheral vascular resistance and mean arterial pressure (MAP) and the deviations from normal were most marked in group 1. Pregnancies with a birthweight <3 rd , compared to those ≥3 rd percentile, had higher deviations from normal in fetal biometry, maternal cardiac output, stroke volume, heart rate and peripheral vascular resistance and UT-PI. Multivariate logistic regression

  12. Detection of gravitational radiation by the Doppler tracking of spacecraft

    International Nuclear Information System (INIS)

    Mashhoon, B.

    1979-01-01

    It has been suggested that the residual Doppler shift in the precision electromagnetic tracking of spacecraft be used to search for gravitational radiation that may be incident on the Earth-spacecraft system. The influence of a gravitational wave on the Doppler shift is calculated, and it is found that the residual shift is dominated by two terms: one is due to the passage of electromagnetic waves through the gravitational radiation field, and the other depends on the change in the relative velocity of the Earth and the spacecraft caused by the external wave. A detailed analysis is given of the influence of gravitational radiation on a binary system with an orbital size small compared to the wavelength of the incident radiation. It is shown that, as a consequence of the interaction with the external wave, the system makes a transition from one Keplerian orbit into another which, in general, has a different energy and angular momentum. It is therefore proposed to search for such effects in the solar system. Observations of the orbit of an artificial Earth satellite, the lunar orbit, and especially the planetary orbits offer exciting possibilities for the detection of gravitational waves of various wavelengths. From the results of the lunar laser ranging experiment and the range measurement to Mars, certain interesting limits may be established on the frequency of incidence of gravitational waves of a given flux on the Earth-Moon and the Earth-Mars systems. This is followed by a brief and preliminary analysis of the possibility of detecting gravitational radiation by measuring a residual secular Doppler shift in the satellite-to-satellite Doppler tracking of two counterorbiting drag-free spacecraft around the Earth as in the Van Patten-Everitt experiment

  13. The effect of blood acceleration on the ultrasound power Doppler spectrum

    Science.gov (United States)

    Matchenko, O. S.; Barannik, E. A.

    2017-09-01

    The purpose of the present work was to study the influence of blood acceleration and time window length on the power Doppler spectrum for Gaussian ultrasound beams. The work has been carried out on the basis of continuum model of the ultrasound scattering from inhomogeneities in fluid flow. Correlation function of fluctuations has been considered for uniformly accelerated scatterers, and the resulting power Doppler spectra have been calculated. It is shown that within the initial phase of systole uniformly accelerated slow blood flow in pulmonary artery and aorta tends to make the correlation function about 4.89 and 7.83 times wider, respectively, than the sensitivity function of typical probing system. Given peak flow velocities, the sensitivity function becomes, vice versa, about 4.34 and 3.84 times wider, respectively, then the correlation function. In these limiting cases, the resulting spectra can be considered as Gaussian. The optimal time window duration decreases with increasing acceleration of blood flow and equals to 11.62 and 7.54 ms for pulmonary artery and aorta, respectively. The width of the resulting power Doppler spectrum is shown to be defined mostly by the wave vector of the incident field, the duration of signal and the acceleration of scatterers in the case of low flow velocities. In the opposite case geometrical properties of probing field and the average velocity itself are more essential. In the sense of signal-noise ratio, the optimal duration of time window can be found. Abovementioned results may contribute to the improved techniques of Doppler ultrasound diagnostics of cardiovascular system.

  14. [Comparison between two methods for hemodynamic measurement: thermodilution and oesophageal doppler].

    Science.gov (United States)

    Ferreira, Roberto Manara Victorio; do Amaral, José Luiz Gomes; Valiatti, Jorge Luís dos Santos

    2007-01-01

    Thermodilution (TD) is the "gold standard method" for hemodynamic monitoring. Some parameters can be measured by Oesophageal Doppler (OD), which is simpler and less invasive. To evaluate the accuracy of OD, we compared this method with TD in measurement of cardiac output (CO). One hundred and ninety two simultaneous measurements were made in 10 patients (5 male and 5 female) with different clinical situations, 8 with sepsis using vasoactive drugs and 2 monitored for laryngectomy and liver transplantation. Measurements were taken during 4 hours at 30 minute intervals. The two oesophageal dopplers used DeltexR and ArrowR, were introduced between 35 and 45 cm from the nose and located at the point of largest diameter of the descending aorta. In TD, we used the pulmonary artery catheter (Swan Ganz BaxterR) and the DX- 2001 monitorR positioning was confirmed with support of radiology and of pressures curves. Measurements of CO carried out by means of TD were achieved using an iced saline solution considering the mean of four measurements with less than a 5% difference. The statistical method used was the Bland-Altman scatter plot and dispersion graphic. No statistically significant difference was found between the two methods for hemodyamic measurement with a correlation coefficient of 0.8 for CO (Deltex DopplerR and Baxter Swan GanzR) and a correlation coefficient of 0.99 for CO (Arrow DopplerR and Baxter Swan GanzR). Homodynamic measurements with OD have the same accuracy as those with TD and were easily obtained in the 10 patients.

  15. Measurement of portal blood flow in healthy individuals: a comparison between magnetic resonance imaging and Doppler ultrasound

    International Nuclear Information System (INIS)

    Costa, Juliana Dantas da; Sebastiane, Patricia Moreno; Leao, Alberto Ribeiro de Souza; Santos, Jose Eduardo Mourao; Moulin, Danilo Sales; D'Ippolito, Giuseppe

    2008-01-01

    Objective: To evaluate the inter-observer agreement between Doppler ultrasonography and magnetic resonance imaging in the quantification of portal blood flow in healthy individuals, as well as evaluating the reproducibility of both methods. Materials and methods: A prospective, transverse, observational and self-paired study was developed evaluating 20 healthy volunteers whose portal blood flow was measured by means of Doppler ultrasonography and magnetic resonance imaging performed by two independent observers. Interobserver and inter method agreements were calculated using the intra class and Pearson's correlation coefficients. Results: The agreement between Doppler ultrasonography and magnetic resonance imaging was low (intra class coefficient: 1.9%-18.2%; Pearson's coefficient: 0.1%-13.7%; p=0.565). Mean values for the portal blood flow measured by Doppler ultrasonography and magnetic resonance imaging were respectively 0.768 l/min and 0.742 l/min. Interobserver agreement for quantification of the portal blood flow by Doppler ultrasonography and magnetic resonance imaging was respectively reasonable (intra class coefficient: 43.3%; Pearson's coefficient: 43.0%) and excellent (intra class coefficient: 91.4%; Pearson's coefficient: 93.4%). Conclusion: In the present study, magnetic resonance imaging demonstrated to be a reliable method for quantifying the portal blood flow, with a higher interobserver agreement than Doppler ultrasonography. The inter method agreement was low. (author)

  16. A Prospective Study of Doppler Velocimetry in Pregnancy-induced ...

    African Journals Online (AJOL)

    Mubeen

    In umbilical artery Doppler, when S/D ratio was abnormal, ... count, differential count, erythrocyte sedimentation rate, hemoglobin percentage ... uric acid, VDRL tests, Hepatitis B surface antigen, HIV), ..... We are planning for a larger project in.

  17. Doppler Lidar Wind Value-Added Product

    Energy Technology Data Exchange (ETDEWEB)

    Newsom, R. K. [DOE ARM Climate Research Facility, Washington, DC (United States); Sivaraman, C. [DOE ARM Climate Research Facility, Washington, DC (United States); Shippert, T. R. [DOE ARM Climate Research Facility, Washington, DC (United States); Riihimaki, L. D. [DOE ARM Climate Research Facility, Washington, DC (United States)

    2015-07-01

    Wind speed and direction, together with pressure, temperature, and relative humidity, are the most fundamental atmospheric state parameters. Accurate measurement of these parameters is crucial for numerical weather prediction. Vertically resolved wind measurements in the atmospheric boundary layer are particularly important for modeling pollutant and aerosol transport. Raw data from a scanning coherent Doppler lidar system can be processed to generate accurate height-resolved measurements of wind speed and direction in the atmospheric boundary layer.

  18. Using the global positioning satellite system to determine attitude rates using doppler effects

    Science.gov (United States)

    Campbell, Charles E. (Inventor)

    2003-01-01

    In the absence of a gyroscope, the attitude and attitude rate of a receiver can be determined using signals received by antennae on the receiver. Based on the signals received by the antennae, the Doppler difference between the signals is calculated. The Doppler difference may then be used to determine the attitude rate. With signals received from two signal sources by three antennae pairs, the three-dimensional attitude rate is determined.

  19. Ultrasonography and color Doppler in juvenile idiopathic arthritis

    DEFF Research Database (Denmark)

    Laurell, Louise; Court-Payen, Michel; Nielsen, Susan

    2011-01-01

    hypertrophy, effusion) and by color Doppler (synovial hyperemia) before and 4 weeks after US-guided steroid injection. Results US detected 121 compartments with active disease (joints, tendon sheaths and 1 ganglion cyst). Multiple compartments were involved in 80% of the ankle regions. The talo-crural joint...

  20. Structure of a swirl-stabilized spray flame by imaging, laser Doppler velocimetry, and phase Doppler anemometry

    Science.gov (United States)

    Edwards, C. F.; Rudoff, R. C.

    1991-01-01

    Data are presented which describe the mean structure of a steady, swirl-stabilized, kerosene spray flame in the near-injector region of a research furnace. The data presented include ensemble-averaged results of schlieren, luminosity, and extinction imaging, measurement of the gas phase velocity field by laser Doppler velocimetry, and characterization of the condensed phase velocity by phase Doppler anemometry. The results of these studies define six key regions in the flame: the dense spray region; the rich, two-phase, fuel jet; the main air jet; the internal product recirculation zone; the external product recirculation zone; and the gaseous diffusion flame zone. The first five of these regions form a conical mixing layer which prepares the air and fuel for combustion. The air and fuel jets comprise the central portion of this mixing layer and are bounded on either side by the hot product gases of the internal and external recirculation zones. Entrainment of these product gases into the air/fuel streams provides the energy required to evaporate the fuel spray and initiate combustion. Intermittency of the internal recirculation and spray jet flows accounts for unexpected behavior observed in the aerodynamics of the two phases. The data reported herein are part of the database being accumulated on this spray flame for the purpose of detailed comparison with numerical modeling.

  1. The Dependence of the Resonance Integral on the Doppler Effect

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, J

    1960-12-15

    The Doppler sensitive contributions to the resonance integral for metal and oxide cylinders have been calculated using tables compiled by Adler, Hinman and Nordheim. The temperatures 20, 200, 350, 500 and 650 deg C have been investigated for the pure metal and 20, 300, 600, 900 and 1200 deg C for the oxide. Contributions from the separate resonances in the resolved region and for certain energies in the unresolved region are accounted for in detail. Integration over adequate statistical distributions has been carried out for the resonance parameters in the unresolved region. The increase in the resonance integral at elevated temperatures due to the Doppler effect is given separately in tables and diagrams.

  2. Prenatal color Doppler ultrasonographic diagnosis of fetal tetralogy of Fallot

    International Nuclear Information System (INIS)

    Tan Buqiao

    2009-01-01

    Objective: To investigate the sonographic findings of tetralogy of Fallot in fetuses. Methods: The data of color Doppler ultrasonography and follow-up results of 5 fetal tetralogy of Fallot were analyzed retrospectively, and their abnormal ultrasound imaging characteristic were summarized. Results: Two cases were proved tetralogy of Fallot by autopsy, and three cases were confirmed to be tetralogy of Fallot by echocardiography after birth. The image features were the main aorta situated above the ventricular septal defect, pulmonary stenosis, no obvious thickening of the right wall. Conclusion: Fetal tetralogy of Fallot have characteristic ultrasound images, prenatal color Doppler ultrasonographic can diagnoses fetal tetralogy of Fallot correctly and has important clinical value. (authors)

  3. Magneto-optic Doppler analyzer: a new instrument to measure mesopause winds

    Science.gov (United States)

    Williams, Bifford P.; Tomczyk, Steven

    1996-11-01

    The magneto-optic Doppler analyzer (MODA) is a new type of passive optical instrument that one can use to measure the Doppler shift of the sodium nightglow emitted at approximately 91 km near the mesopause. From this measurement, horizontal wind signatures are inferred. The MODA is based on a sodium vapor magneto-optic filter that provides inherent wavelength stability at a low cost. The instrument has been used to take nightly zonal and meridional wind measurements since October 1994 at Niwot Ridge, Colorado (40 N, 105 W). We obtained an internally consistent wind signal and measured the semidiurnal tide for several seasons.

  4. Measurement of Doppler effect up to 2000degC at FCA. 1

    International Nuclear Information System (INIS)

    Oigawa, Hiroyuki; Okajima, Shigeaki; Mukaiyama, Takehiko; Satoh, Kunio; Hishida, Makoto; Hayano, Mutsuhiko; Kudogh, Fumio; Kasahara, Yoshiyuki.

    1994-03-01

    A new experimental device for the measurement of 238 U Doppler effect up to 2000degC was developed for the Fast Critical Assembly (FCA) of Japan Atomic Energy Research Institute with the intention to improve the Doppler effect analysis at high temperature in fast reactors. The measurement method consists of two different techniques; one is the reactivity worth measurement with using a small sample heated up to 1500degC, the other is the reaction rate measurement with using a foil heated up to 2000degC. In the present work, the development and measurement for the former technique is described. The technique itself had been used in critical assemblies around the world, including FCA, for the measurement up to 800degC. The present new device was developed by improving the old device throughouly to extend the sample temperature up to 1500degC which is hot enough for us to evaluate the Doppler effect in the MOX-fuel fast reactor. (author)

  5. Multipoint photonic doppler velocimetry using optical lens elements

    Science.gov (United States)

    Frogget, Brent Copely; Romero, Vincent Todd

    2014-04-29

    A probe including a fisheye lens is disclosed to measure the velocity distribution of a moving surface along many lines of sight. Laser light, directed to the surface and then reflected back from the surface, is Doppler shifted by the moving surface, collected into fisheye lens, and then directed to detection equipment through optic fibers. The received light is mixed with reference laser light and using photonic Doppler velocimetry, a continuous time record of the surface movement is obtained. An array of single-mode optical fibers provides an optic signal to an index-matching lens and eventually to a fisheye lens. The fiber array flat polished and coupled to the index-matching lens using index-matching gel. Numerous fibers in a fiber array project numerous rays through the fisheye lens which in turn project many measurement points at numerous different locations to establish surface coverage over a hemispherical shape with very little crosstalk.

  6. Power doppler ultrasound findings of renal infarct after experimental renal artery occlusion: comparison with spiral CT

    International Nuclear Information System (INIS)

    Jung, Seung Eun; Shinn, Kyung Sub; Kim, Hak Hee; Mun, Seok Hwan; Lee, Young Joon; Lee, Bae Young; Choi, Byung Gil; Lee, Jae Mun; Lee, Hee Jeong

    1999-01-01

    To evaluate the efficacy of power Doppler ultrasonography (PDUS) in depicting renal infarction in rabbits during experimental renal segmental arterial occlusion, and to compare the results with those of CT scanning. In 28 rabbits weighing 2.5 4kg, the segmental renal artery was occluded through the left main renal artery by embolization with Ivalon (Nycomed, Paris, France). Power Doppler ultrasonography and spiral CT scanning were performed before and at 2, 5, 8, 15, and 24 hours, and 3 and 7 days after occlusion of the segmental renal artery. The location of infarcted areas and collaterals, as seen on PDUS and CT scans, was evaluated by two radiologists. In all cases, as seen on power Doppler ultrasonography, infarcted areas-when compared with normal parenchyma, clearly demonstrated wedge-shaped perfusion defects in the kidney. The location of the lesion closely corresponded to the location seen during CT scanning. After renal arterial occlusion, transiently congested capsular arteries, which were named 'capsular sign', were seen in 63% of rabbits in the two and five-hour groups. No significant cortical rim sign was demonstrated on power Doppler ultrasonography, though it was noted on spiral CT at 15 and 24 hours, and 3 and 7 days after renal arterial occlusion. Power Doppler ultrasonography was useful for the diagnosis of renal infarction. Congested capsular artery seen in the early stage of renal infarction might be a characteristic finding of this condition, as seen on power Doppler ultrasonography

  7. Tissue Doppler Imaging in the evaluation of abdominal aortic pulsatility: a useful tool for the neonatologist.

    Science.gov (United States)

    Valerio, Enrico; Grison, Alessandra; Capretta, Anna; Golin, Rosanna; Ferrarese, Paola; Bellettato, Massimo

    2017-03-01

    Sonographic cardiac evaluation of newborns with suspected aortic coarctation (AoC) should tend to demonstrate a good phasic and pulsatile flow and the absence of pressure gradient along a normally conformed aortic arch from the modified left parasternal and suprasternal echocardiographic views; these findings, however, may not necessarily rule out a more distal coarctation in the descending aorta. For this reason, the sonographic exam of newborns with suspected AoC should always include a Doppler evaluation of abdominal aortic blood flow from the subcostal view. Occasionally, however, a clearly pulsatile Doppler flow trace in abdominal aorta may be difficult to obtain due to the bad insonation angle existing between the probe and the vessel. In such suboptimal ultrasonic alignment situation, the use of Tissue Doppler Imaging instead of classic Doppler flow imaging may reveal a preserved aortic pulsatility by sampling the aortic wall motion induced by normal flow. We propose to take advantage of the TDI pattern as a surrogate of a normal pulsatile Doppler flow trace in abdominal aorta when the latter is difficult to obtain due to malalignment with the insonated vessel.

  8. Doppler method leak detection for LMFBR steam generators. Pt. 3. Investigation of detection sensitivity and method

    International Nuclear Information System (INIS)

    Kumagai, Hiromichi; Kinoshita, Izumi

    2001-01-01

    To prevent the expansion of tube damage and to maintain structural integrity in the steam generators (SGs) of a fast breeder reactor (FBR), it is necessary to detect precisely and immediately any leakage of water from heat transfer tubes. Therefore, the Doppler method was developed. Previous studies have revealed that, in the SG full-sector model that simulates actual SGs, the Doppler method can detect bubbles of 0.4 l/s within a few seconds. However in consideration of the dissolution rate of hydrogen generated by a sodium-water reaction even from a small water leak, it is necessary to detect smaller leakages of water from the heat transfer tubes. The detection sensitivity of the Doppler method and the influence of background noise were experimentally investigated. In-water experiments were performed using the SG model. The results show that the Doppler method can detect bubbles of 0.01 l/s (equivalent to a water leak rate of about 0.01 g/s) within a few seconds and that the background noise has little effect on water leak detection performance. The Doppler method thus has great potential for the detection of water leakage in SGs. (author)

  9. Laser Doppler velocimetry based on the optoacoustic effect in a RF-excited CO{sub 2} laser

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Teaghee; Choi, Jong Woon [Department of Information and Communication, Honam University, Seobong-dong 59-1, Gwansan-gu, Gwangju 506-714 (Korea, Republic of); Kim, Yong Pyung [College of Electronics and Information, Kyunghee University, 1 Seocheon-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-701 (Korea, Republic of)

    2012-09-15

    We present a compact optoacoustic laser Doppler velocimetry method that utilizes the self-mixing effect in a RF-excited CO{sub 2} laser. A portion of a Doppler-shifted laser beam, produced by irradiating a single wavelength laser beam on a moving object, is mixed with an originally existing laser beam inside a laser cavity. The fine change of pressure in the laser cavity modulated by the Doppler-shifted frequency is detected by a condenser microphone in the laser tube. In our studies, the frequency of the Doppler signal due to the optoacoustic effect was detected as high as 50 kHz. Our measurements also confirmed that the signal varied linearly with the velocity of the external scatterer (the moving object) and the cosine of the angle between the laser beam and the velocity vector of the object.

  10. Clinical study of color Doppler sonography in Graves' disease blood flow changes after thyroid arteries embolization

    International Nuclear Information System (INIS)

    Zhuang Wenquan; Li Weiduo; Yang Jianyong; Chen Wei; Huang Yonghui; Guo Wenbo; Li Jiaping

    2003-01-01

    Objective: To study the color doppler image characteristics of thyroid arteries pre- and post-interventional procedure and to assess the clinical efficacy in Gnaves' disease. Methods: 11 from 31 patients diagnosed as Graves' disease undertaken thyroid arteries embolization, were analyzed. Color Doppler sonography was applied to monitor the pre-and post- procedure thyroid size and diameters of thyroid arteries. Power Doppler was used to detect the Vmax, Vmin, RI and blood flow. Results: After thyroid arteries embolization, the size and vascularity of thyroids were reduced. The thyroid arteries showed shrinkage and stoppage blood flow at the embolized site. The changes of RI, blood parameters of Vmax, Vmin and diameters of the thyroid arteries pre- and post-procedure turned out to be statistically significant for clinical restriction. Conclusion: The color Doppler sonography plays an important role for preoperative diagnosis and predicting the prognosis

  11. Transient basilar artery occlusion monitored by transcranial color Doppler presenting with a spectacular shrinking deficit: a case report

    Directory of Open Access Journals (Sweden)

    Del Sette Massimo

    2010-01-01

    Full Text Available Abstract Introduction We describe the case of a 79-year-old Caucasian Italian woman with a transient basilar occlusion monitored by transcranial Doppler, with subsequent recanalization and clinical shrinking deficit. This is the first case of transient basilar occlusive disease diagnosed and monitored by transcranial Doppler. This case is important and needs to be reported because transient basilar occlusion may be easily diagnosed if transcranial Doppler is performed. Case presentation A 79-year-old woman affected by chronic atrial fibrillation and not treated with oral anticoagulants, cardioverted to sinus rhythm during a gastric endoscopy. She then showed a sudden-onset loss of consciousness, horizontal and vertical gaze palsy, tetraparesis and bilateral miosis and coma. Two hours later, the symptoms resolved quickly, leaving no residual neurologic deficits. Transcranial Doppler examination showed a dampened flow in the basilar artery in the emergency examination and a restored flow when the symptoms resolved. Conclusion This is the first case of transient basilar occlusive disease diagnosed and monitored by transcranial Doppler. We believe that transcranial Doppler should be performed in all cases of unexplained acute loss of consciousness, in particular, if associated with signs of brainstem dysfunctions.

  12. Poststenotic flow disturbance in the dog aorta as measured with pulsed Doppler ultrasound.

    Science.gov (United States)

    Talukder, N; Fulenwider, J T; Mabon, R F; Giddens, D P

    1986-08-01

    Blood flow velocity was measured in the dog aorta distal to mechanically induced constrictions of various degrees of severity employing an 8-MHz pulsed Doppler ultrasound velocimeter and a phase-lock loop frequency tracking method for extracting velocity from the Doppler quadrature signals. The data were analyzed to construct ensemble average velocity waveforms and random velocity disturbances. In any individual animal the effect of increasing the degree of stenosis beyond approximately 25 percent area reduction was to produce increasing levels of random velocity disturbance. However, variability among animals was such that the sensitivity of random behavior to the degree of stenosis was degraded to the point that it appears difficult to employ Doppler ultrasound measurements of random disturbances to discriminate among stenoses with area reductions less than approximately 75 percent. On the other hand, coherent vortex structures in velocity waveforms consistently occurred distal to mild constrictions (25-50 percent area reduction). Comparison of the phase-lock loop Doppler ultrasound data with simultaneous measurements using invasive hot-film anemometry, which possesses excellent frequency response, demonstrates that the ultrasound method can reliably detect those flow phenomena in such cases. Thus, the identification of coherent, rather than random, flow disturbances may offer improved diagnostic capability for noninvasively detecting arteriosclerotic plaques at relatively early stages of development.

  13. [Current role of color Doppler ultrasound in acute renal failure].

    Science.gov (United States)

    Bertolotto, M; Quaia, E; Rimondini, A; Lubin, E; Pozzi Mucelli, R

    2001-01-01

    Acute Renal Failure (ARF) is characterized by a rapid decline of the glomerular filtration rate, due to hypotension (prerenal ARF), obstruction of the urinary tract (post-renal ARF) or renal parenchymal disease (renal ARF). The differential diagnosis among different causes of ARF is based on anamnesis, clinical symptoms and laboratory data. Usually ultrasound (US) is the only imaging examination performed in these patients, because it is safe and readily available. In patients with ARF gray scale US is usually performed to rule out obstruction since it is highly sensitive to recognize hydronephrosis. Patients with renal ARF have no specific changes in renal morphology. The size of the kidneys is usually normal or increased, with smooth margins. Detection of small kidneys suggests underlying chronic renal pathology and worse prognosis. Echogenicity and parenchymal thickness are usually normal, but in some cases there are hyperechogenic kidneys, increased parenchymal thickness and increased cortico-medullary differentiation. Evaluation of renal vasculature with pulsed Doppler US is useful in the differential diagnosis between prerenal ARF and acute tubular necrosis (ATN), and in the diagnosis of renal obstruction. Latest generation US apparatus allow color Doppler and power Doppler evaluation of renal vasculature up to the interlobular vessels. A significant, but non specific, reduction in renal perfusion is usually appreciable in the patients with ARF. There are renal pathologic conditions presenting with ARF in which color Doppler US provides more specific morphologic and functional information. In particular, color Doppler US often provides direct or indirect signs which can lead to the right diagnosis in old patients with chronic renal insufficiency complicated with ARF, in patients with acute pyelonephritis, hepatic disease, vasculitis, thrombotic microangiopathies, and in patients with acute thrombosis of the renal artery and vein. Contrast enhanced US is

  14. An Acoustic OFDM System with Symbol-by-Symbol Doppler Compensation for Underwater Communication.

    Science.gov (United States)

    MinhHai, Tran; Rie, Saotome; Suzuki, Taisaku; Wada, Tomohisa

    2016-01-01

    We propose an acoustic OFDM system for underwater communication, specifically for vertical link communications such as between a robot in the sea bottom and a mother ship in the surface. The main contributions are (1) estimation of time varying Doppler shift using continual pilots in conjunction with monitoring the drift of Power Delay Profile and (2) symbol-by-symbol Doppler compensation in frequency domain by an ICI matrix representing nonuniform Doppler. In addition, we compare our proposal against a resampling method. Simulation and experimental results confirm that our system outperforms the resampling method when the velocity changes roughly over OFDM symbols. Overall, experimental results taken in Shizuoka, Japan, show our system using 16QAM, and 64QAM achieved a data throughput of 7.5 Kbit/sec with a transmitter moving at maximum 2 m/s, in a complicated trajectory, over 30 m vertically.

  15. Renal Doppler Indices in Children with Nephrotic Syndrome ...

    African Journals Online (AJOL)

    Summary: The resistive and pulsatility indices are known tools for assessing renal function in kidney diseases, especially in proteinuric conditions like Paediatric Nephrotic syndrome (NS) which is a glomerular disease. However, there is a limited knowledge in the use of Doppler Resistive and pulsatility indices in the ...

  16. Effect of preload alternations on a new Doppler echocardiographic index of combined systolic and diastolic performance

    DEFF Research Database (Denmark)

    Møller, J E; Poulsen, S H; Egstrup, K

    1999-01-01

    The objective of the study was to assess the effect of preload alternations on a nongeometric Doppler index of combined systolic and diastolic myocardial performance (MPI). Doppler echocardiography was performed during Valsalva maneuver, passive leg lifting, and after sublingual administration of...

  17. Homogenization of Doppler broadening in spin-noise spectroscopy

    Science.gov (United States)

    Petrov, M. Yu.; Ryzhov, I. I.; Smirnov, D. S.; Belyaev, L. Yu.; Potekhin, R. A.; Glazov, M. M.; Kulyasov, V. N.; Kozlov, G. G.; Aleksandrov, E. B.; Zapasskii, V. S.

    2018-03-01

    The spin-noise spectroscopy, being a nonperturbative linear optics tool, is still reputed to reveal a number of capabilities specific to nonlinear optics techniques. The effect of the Doppler broadening homogenization discovered in this work essentially widens these unique properties of spin-noise spectroscopy. We investigate spin noise of a classical system—cesium atoms vapor with admixture of buffer gas—by measuring the spin-induced Faraday rotation fluctuations in the region of D 2 line. The line, under our experimental conditions, is strongly inhomogeneously broadened due to the Doppler effect. Despite that, optical spectrum of the spin-noise power has the shape typical for the homogeneously broadened line with a dip at the line center. This fact is in stark contrast with the results of previous studies of inhomogeneous quantum dot ensembles and Doppler broadened atomic systems. In addition, the two-color spin-noise measurements have shown, in a highly spectacular way, that fluctuations of the Faraday rotation within the line are either correlated or anticorrelated depending on whether the two wavelengths lie on the same side or on different sides of the resonance. The experimental data are interpreted in the frame of the developed theoretical model which takes into account both kinetics and spin dynamics of Cs atoms. It is shown that the unexpected behavior of the Faraday rotation noise spectra and effective homogenization of the optical transition in the spin-noise measurements are related to smallness of the momentum relaxation time of the atoms as compared with their spin-relaxation time. Our findings demonstrate abilities of spin-noise spectroscopy for studying dynamic properties of inhomogeneously broadened ensembles of randomly moving spins.

  18. Performance evaluation of a thermal Doppler Michelson interferometer system.

    Science.gov (United States)

    Mani, Reza; Dobbie, Steven; Scott, Alan; Shepherd, Gordon; Gault, William; Brown, Stephen

    2005-11-20

    The thermal Doppler Michelson interferometer is the primary element of a proposed limb-viewing satellite instrument called SWIFT (Stratospheric Wind Interferometer for Transport studies). SWIFT is intended to measure stratospheric wind velocities in the altitude range of 15-45 km. SWIFT also uses narrowband tandem etalon filters made of germanium to select a line out of the thermal spectrum. The instrument uses the same technique of phase-stepping interferometry employed by the Wind Imaging Interferometer onboard the Upper Atmosphere Research Satellite. A thermal emission line of ozone near 9 microm is used to detect the Doppler shift due to winds. A test bed was set up for this instrument that included the Michelson interferometer and the etalon filters. For the test bed work, we investigate the behavior of individual components and their combination and report the results.

  19. Micro-Doppler Signal Time-Frequency Algorithm Based on STFRFT

    Directory of Open Access Journals (Sweden)

    Cunsuo Pang

    2016-09-01

    Full Text Available This paper proposes a time-frequency algorithm based on short-time fractional order Fourier transformation (STFRFT for identification of a complicated movement targets. This algorithm, consisting of a STFRFT order-changing and quick selection method, is effective in reducing the computation load. A multi-order STFRFT time-frequency algorithm is also developed that makes use of the time-frequency feature of each micro-Doppler component signal. This algorithm improves the estimation accuracy of time-frequency curve fitting through multi-order matching. Finally, experiment data were used to demonstrate STFRFT’s performance in micro-Doppler time-frequency analysis. The results validated the higher estimate accuracy of the proposed algorithm. It may be applied to an LFM (Linear frequency modulated pulse radar, SAR (Synthetic aperture radar, or ISAR (Inverse synthetic aperture radar, for improving the probability of target recognition.

  20. Micro-Doppler Signal Time-Frequency Algorithm Based on STFRFT.

    Science.gov (United States)

    Pang, Cunsuo; Han, Yan; Hou, Huiling; Liu, Shengheng; Zhang, Nan

    2016-09-24

    This paper proposes a time-frequency algorithm based on short-time fractional order Fourier transformation (STFRFT) for identification of a complicated movement targets. This algorithm, consisting of a STFRFT order-changing and quick selection method, is effective in reducing the computation load. A multi-order STFRFT time-frequency algorithm is also developed that makes use of the time-frequency feature of each micro-Doppler component signal. This algorithm improves the estimation accuracy of time-frequency curve fitting through multi-order matching. Finally, experiment data were used to demonstrate STFRFT's performance in micro-Doppler time-frequency analysis. The results validated the higher estimate accuracy of the proposed algorithm. It may be applied to an LFM (Linear frequency modulated) pulse radar, SAR (Synthetic aperture radar), or ISAR (Inverse synthetic aperture radar), for improving the probability of target recognition.

  1. Doppler shift simulation of scattered HF signals during the Tromsø HF pumping experiment on 16 February 1996

    Directory of Open Access Journals (Sweden)

    T. D. Borisova

    2002-09-01

    Full Text Available Comparisons between bistatic scatter measurements and simulation results during the Tromsø HF pumping experiment on 16 February 1996 are made. Doppler measurements of an HF diagnostic signal scattered from the field-aligned irregularities (FAIs in the auroral E-region were carried out on the London – Tromsø – St. Petersburg path at 9410 kHz from 21:00 to 22:00 UT. The scattered signals were observed both from natural and artificial ionospheric irregularities located in the vicinity of Tromsø. To simulate the Doppler frequency shifts, fd , of scattered signals, a radio channel model, named CONE, was developed. The model allows for ray tracing, group and phase paths, and Doppler frequency shift calculations. The calculated Doppler shifts were analyzed for dependence on the magnitude and direction of plasma velocities in the scattering volume. It was found that the velocity components in the north-south direction are crucial for explaining the Doppler frequency shifts of the scattered diagnostic signals. To simulate fd , real velocities obtained from the EISCAT UHF radar at an altitude of 278 km and from the digital all-sky imager during the experiment were employed. The simulation results of Doppler frequency shift variations with time are in reasonable agreement with the experimental Doppler shifts of scattered signals on the London – Tromsø – St. Petersburg path.Key words. Ionosphere (active experiments; ionospheric irregularities Radio science (ionospheric propagation

  2. Carotid near-occlusion frequently has high peak systolic velocity on Doppler ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Khangure, Simon R.; Machnowska, Matylda; Fox, Allan J.; Hojjat, Seyed-Parsa; Aviv, Richard I. [Sunnybrook Health Sciences Centre, Department of Medical Imaging, Neuroradiology Division, Toronto, ON (Canada); University of Toronto, Department of Medical Imaging, Division of Neuroimaging, Toronto (Canada); Benhabib, Hadas [Sunnybrook Health Sciences Centre, Department of Medical Imaging, Neuroradiology Division, Toronto, ON (Canada); Groenlund, Christer [Umeaa University, Department of Radiation Sciences, Biomedical Engineering, Umeaa (Sweden); Herod, Wendy [Department of Surgery, Sunnybrook Health Sciences Centre, Toronto (Canada); Maggisano, Robert [Department of Surgery, Sunnybrook Health Sciences Centre, Toronto (Canada); University of Toronto, Division of Vascular Surgery, Department of Surgery, Toronto (Canada); Sjoeberg, Anders [Umeaa University, Department of Radiation Sciences, Biomedical Engineering, Umeaa (Sweden); Umeaa University, Department of Pharmacology and Clinical Neuroscience, Umeaa (Sweden); Wester, Per [Umeaa University, Department of Public Health and Clinical Medicine, Umeaa (Sweden); Karolinska Institutet Danderyds Hospital, Department of Clinical Sciences, Stockholm (Sweden); Hopyan, Julia [University of Toronto, Division of Neurology, Department of Medicine, Toronto (Canada); Johansson, Elias [Umeaa University, Department of Pharmacology and Clinical Neuroscience, Umeaa (Sweden); Umeaa University, Department of Public Health and Clinical Medicine, Umeaa (Sweden)

    2018-01-15

    Carotid near-occlusion is a tight atherosclerotic stenosis of the internal carotid artery (ICA) resulting in decrease in diameter of the vessel lumen distal to the stenosis. Near-occlusions can be classified as with or without full collapse, and may have high peak systolic velocity (PSV) across the stenosis, mimicking conventional > 50% carotid artery stenosis. We aimed to determine how frequently near-occlusions have high PSV in the stenosis and determine how accurately carotid Doppler ultrasound can distinguish high-velocity near-occlusion from conventional stenosis. Included patients had near-occlusion or conventional stenosis with carotid ultrasound and CT angiogram (CTA) performed within 30 days of each other. CTA examinations were analyzed by two blinded expert readers. Velocities in the internal and common carotid arteries were recorded. Mean velocity, pulsatility index, and ratios were calculated, giving 12 Doppler parameters for analysis. Of 136 patients, 82 had conventional stenosis and 54 had near-occlusion on CTA. Of near-occlusions, 40 (74%) had high PSV (≥ 125 cm/s) across the stenosis. Ten Doppler parameters significantly differed between conventional stenosis and high-velocity near-occlusion groups. However, no parameter was highly sensitive and specific to separate the groups. Near-occlusions frequently have high PSV across the stenosis, particularly those without full collapse. Carotid Doppler ultrasound does not seem able to distinguish conventional stenosis from high-velocity near-occlusion. These findings question the use of ultrasound alone for preoperative imaging evaluation. (orig.)

  3. High-frequency dual mode pulsed wave Doppler imaging for monitoring the functional regeneration of adult zebrafish hearts

    Science.gov (United States)

    Kang, Bong Jin; Park, Jinhyoung; Kim, Jieun; Kim, Hyung Ham; Lee, Changyang; Hwang, Jae Youn; Lien, Ching-Ling; Shung, K. Kirk

    2015-01-01

    Adult zebrafish is a well-known small animal model for studying heart regeneration. Although the regeneration of scars made by resecting the ventricular apex has been visualized with histological methods, there is no adequate imaging tool for tracking the functional recovery of the damaged heart. For this reason, high-frequency Doppler echocardiography using dual mode pulsed wave Doppler, which provides both tissue Doppler (TD) and Doppler flow in a same cardiac cycle, is developed with a 30 MHz high-frequency array ultrasound imaging system. Phantom studies show that the Doppler flow mode of the dual mode is capable of measuring the flow velocity from 0.1 to 15 cm s−1 with high accuracy (p-value = 0.974 > 0.05). In the in vivo study of zebrafish, both TD and Doppler flow signals were simultaneously obtained from the zebrafish heart for the first time, and the synchronized valve motions with the blood flow signals were identified. In the longitudinal study on the zebrafish heart regeneration, the parameters for diagnosing the diastolic dysfunction, for example, E/Em < 10, E/A < 0.14 for wild-type zebrafish, were measured, and the type of diastolic dysfunction caused by the amputation was found to be similar to the restrictive filling. The diastolic function was fully recovered within four weeks post-amputation. PMID:25505135

  4. Ultrasonography and color Doppler in juvenile idiopathic arthritis

    DEFF Research Database (Denmark)

    Laurell, Louise; Court-Payen, Michel; Nielsen, Susan

    2012-01-01

    The wrist region is one of the most complex joints of the human body. It is prone to deformity and functional impairment in juvenile idiopathic arthritis (JIA), and is difficult to examine clinically. The aim of this study was to evaluate the role of ultrasonography (US) with Doppler in diagnosis...

  5. A novel decision tree approach based on transcranial Doppler sonography to screen for blunt cervical vascular injuries.

    Science.gov (United States)

    Purvis, Dianna; Aldaghlas, Tayseer; Trickey, Amber W; Rizzo, Anne; Sikdar, Siddhartha

    2013-06-01

    Early detection and treatment of blunt cervical vascular injuries prevent adverse neurologic sequelae. Current screening criteria can miss up to 22% of these injuries. The study objective was to investigate bedside transcranial Doppler sonography for detecting blunt cervical vascular injuries in trauma patients using a novel decision tree approach. This prospective pilot study was conducted at a level I trauma center. Patients undergoing computed tomographic angiography for suspected blunt cervical vascular injuries were studied with transcranial Doppler sonography. Extracranial and intracranial vasculatures were examined with a portable power M-mode transcranial Doppler unit. The middle cerebral artery mean flow velocity, pulsatility index, and their asymmetries were used to quantify flow patterns and develop an injury decision tree screening protocol. Student t tests validated associations between injuries and transcranial Doppler predictive measures. We evaluated 27 trauma patients with 13 injuries. Single vertebral artery injuries were most common (38.5%), followed by single internal carotid artery injuries (30%). Compared to patients without injuries, mean flow velocity asymmetry was higher for single internal carotid artery (P = .003) and single vertebral artery (P = .004) injuries. Similarly, pulsatility index asymmetry was higher in single internal carotid artery (P = .015) and single vertebral artery (P = .042) injuries, whereas the lowest pulsatility index was elevated for bilateral vertebral artery injuries (P = .006). The decision tree yielded 92% specificity, 93% sensitivity, and 93% correct classifications. In this pilot feasibility study, transcranial Doppler measures were significantly associated with the blunt cervical vascular injury status, suggesting that transcranial Doppler sonography might be a viable bedside screening tool for trauma. Patient-specific hemodynamic information from transcranial Doppler assessment has the potential to alter

  6. Doppler Ultrasonographic Parameters for Predicting Cerebral Vascular Reserve in Patients with Acute Ischemic Stroke

    International Nuclear Information System (INIS)

    Jung, Han Young; Lee, Hui Joong; Kim, Hye Jung; Kim, Yong Sun; Kang, Duk Sik

    2006-01-01

    We investigated Doppler ultrasonographic (US) parameters of patients with acute stroke to predict the cerebral vascular reserve (CVR) measured by SPECT. We reviewed the flow velocity and cross-sectional area of the circular vessel at the common, external, and internal carotid arteries (ICA) and the vertebral arteries (VA) in 109 acute stroke patients who underwent SPECT. Flow volume (FV) of each artery was calculated as the product of the angle-corrected time averaged flow velocity and cross-sectional area of the circular vessel. Total cerebral FV (TCBFV) was determined as the sum of the FVs of the right and left ICA and VA. We compared the Doppler US parameters between 44 cases of preserved and 65 cases of impaired CVR. In the preserved CVR group, ICA FV, anterior circulating FV (ACFV) and TCBFV were higher than in the impaired CVR group (p < 0.05, independent t-test). In the impaired CVR group, the ROC curves showed ACFV and TCBFV were suitable parameters to predict CVR (p < 0.05). Doppler US was helpful for understanding the hemodynamic state of acute stroke. FV measurement by Doppler US was useful for predicting CVR

  7. Doppler ultrasound and magnetic resonance for evaluation of patients treated surgically for aortic coarctation

    International Nuclear Information System (INIS)

    Canteli, B.; Saez, F.; Garcia, F.; Cabrera, A.; Galdeano, J.M.; Rodriguez, O.

    1994-01-01

    Doppler ultrasound and magnetic resonance were performed in a series of 39 patients who had been treated surgically for aortic coarctation. The purpose was to assess the different Doppler gradients, comparing the findings with morphological data disclosed by magnetic resonance. The aortic caliber in the operative field was pathological in 7 patients (ratio between the caliber at the level of the lesion and that of descending aorta of less than 0.7). When the patients were considered as a group. Doppler ultrasound did not show satisfactory sensitivity (29%-43%), specificity (74%) or positive predictive value (17%-23%). Only the negative predictive value (85%-88%) presented more favorable results. When the Subgroup of patients without associated cardiac abnormalities or collateral circulation was studied alone, the following results were found: sensitivity, 100%; specificity, 81%-90%, positive predictive value, 33%-50%, negative predictive value, 100%, similar to those reported in the literature. Thus, we consider that Doppler ultrasound is a harmless and low cost diagnostic method that is highly suitable for follow-up of these patients, within certain limits. Magnetic resonance is the method of choice for the noninvasive assessment of aortic morphology. (Author)

  8. Reliability of laser Doppler, near-infrared spectroscopy and Doppler ultrasound for peripheral blood flow measurements during and after exercise in the heat.

    Science.gov (United States)

    Choo, Hui C; Nosaka, Kazunori; Peiffer, Jeremiah J; Ihsan, Mohammed; Yeo, Chow C; Abbiss, Chris R

    2017-09-01

    This study examined the test-retest reliability of near-infrared spectroscopy (NIRS), laser Doppler flowmetry (LDF) and Doppler ultrasound to assess exercise-induced haemodynamics. Nine men completed two identical trials consisting of 25-min submaximal cycling at first ventilatory threshold followed by repeated 30-s bouts of high-intensity (90% of peak power) cycling in 32.8 ± 0.4°C and 32 ± 5% relative humidity (RH). NIRS (tissue oxygenation index [TOI] and total haemoglobin [tHb]) and LDF (perfusion units [PU]) signals were monitored continuously during exercise, and leg blood flow was assessed by Doppler ultrasound at baseline and after exercise. Cutaneous vascular conductance (CVC; PU/mean arterial pressure (MAP)) was expressed as the percentage change from baseline (%CVC BL ). Coefficients of variation (CVs) as indicators of absolute reliability were 18.7-28.4%, 20.2-33.1%, 42.5-59.8%, 7.8-12.4% and 22.2-30.3% for PU, CVC, %CVC BL , TOI and tHb, respectively. CVs for these variables improved as exercise continued beyond 10 min. CVs for baseline and post-exercise leg blood flow were 17.8% and 10.5%, respectively. CVs for PU, tHb (r 2  = 0.062) and TOI (r 2  = 0.002) were not correlated (P > 0.05). Most variables demonstrated CVs lower than the expected changes (35%) induced by training or heat stress; however, minimum of 10 min exercise is recommended for more reliable measurements.

  9. CAMEX-4 MIPS 915 MHZ DOPPLER WIND PROFILER V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The University of Alabama in Huntsville (UAH) Mobile Integrated Profiling System (MIPS) is a mobile atmospheric profiling system. It includes a 915 MHz Doppler...

  10. Contrast-enhanced power Doppler endosonography and pathological assessment of vascularization in advanced gastric carcinomas--a feasibility study.

    Science.gov (United States)

    Iordache, Sevastiţa; Filip, Maria-Monalisa; Georgescu, Claudia-Valentina; Angelescu, Cristina; Ciurea, Tudorel; Săftoiu, Adrian

    2012-06-01

    Besides representing angiogenesis markers, microvascular density (MVD) and vascular endothelial growth factor (VEGF) are two important tools for the assessment of prognosis in patients with gastric cancer. The aim of our study was to assess the Doppler parameters (resistivity and pulsatility indexes) and vascularity index (VI) calculated by contrast-enhanced power Doppler endoscopic ultrasound (CEPD-EUS) in correlation with the expression of intra-tumoral MVD and VEGF in patients with gastric cancer. The study included 20 consecutive patients with advanced gastric carcinoma, but without distant metastasis at initial assessment. All the patients were assessed by contrast-enhanced power Doppler endoscopic ultrasound (EUS) combined with pulsed Doppler examinations in the late venous phase. The vascularity index (VI) was calculated before and after injection of second generation microbubble contrast specific agent (SonoVue 2.4 mL), used as a Doppler signal enhancer. Moreover, pulsed Doppler parameters (resistivity and pulsatility indexes) were further calculated. The correlation between power Doppler parameters and pathological/molecular parameters (MVD assessed through immunohistochemistry with CD31 and CD34, as well as VEGF assessed through real-time PCR) was assessed. Kaplan-Meier survival analysis was used for the assessment of prognosis. Significantly statistical correlations were found between post-contrast VI and CD34 (p=0.0226), VEGF (p=0.0231), VEGF-A (p=0.0464) and VEGF-B (p=0.0022) while pre-contrast VI was correlated only with CD34 expression. Pulsatility index and resistivity index were not correlated with MVD or VEGF expression. Survival analysis demonstrated that VEGF-A is an accurate parameter for survival rate (p=0.045), as compared to VEGF (p=0.085) and VEGF-B (p=0.230). We did not find any correlation between the survival rate and ultrasound parameters (RI, PI, pre-contrast VI or post-contrast VI). Assessment of tumor vascularity using contrast

  11. Evaluating the cardiac function of duchenne muscular dystrophy with Doppler Tei index

    International Nuclear Information System (INIS)

    Yao Fengjuan; Zheng Ju; Lu Kun; Liu Donghong; Wu Miaoling; Lin Hong; Zhang Cheng; Yu Hongkui

    2007-01-01

    Objective: To evaluate the cardiac function of early Duchenne muscular dystrophy (DMD) by left ventricular ejection fraction (LVEF) and pulse Doppler Tei index. Methods: Twenty-eight DMD patients and fifteen normal people were studied. LVEF, E/A and Tei index were measured and calculated by M-mode and Pulse wave Doppler respectively. Results: Compared with control group, Tei index and IRT were significantly high, and there were not significant difference in LVEF(%) and E/A. Conclusion: Tei index was valuable in assessing cardiac function of early DMD. (authors)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-12-31

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

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

    DEFF Research Database (Denmark)

    Kjærgaard, Jesper

    2012-01-01

    This thesis summarizes a series of studies performed in order to assess the clinical usefulness of a novel echocardiographic technology that allows non-invasive assessment of regional right ventricular myocardial velocities and deformation: tissue Doppler echocardiography. While the technology...... is a promising tool for improving our understanding of right ventricular hemodynamics, several aspects of the technology must be evaluated. The accuracy and reproducibility of the technology is evaluated in vitro, and normal values, impact of changes in loading of the right ventricle, response to exercise...... on right ventricular hemodynamics: pulmonary embolism, Arrhythmogenic right ventricular cardiomyopathy and pulmonary regurgitation, the latter in an animal model. The conclusions of the thesis are: Color tissue Doppler echocardiography accurately measures velocities, SR and strain in vitro. No systematic...

  14. Passive emitter location with Doppler frequency and interferometric measurements

    NARCIS (Netherlands)

    Groot, J.S.; Dam, F.A.M.; Theil, A.

    2008-01-01

    Ground based emitters can be located with a receiver installed on an airborne platform. This paper discusses techniques based on Doppler frequency and differential phase measurements (interferometry). Measurements of the first technique are provided, while we discuss and compare the theoretical

  15. Doppler ultrasound for diagnosis of soft tissue sarcoma: efficacy of ultrasound-based screening score

    Directory of Open Access Journals (Sweden)

    Nagano Satoshi

    2015-06-01

    Full Text Available Background. The utility of ultrasound imaging in the screening of soft-part tumours (SPTs has been reported. We classified SPTs according to their blood flow pattern on Doppler ultrasound and re-evaluated the efficacy of this imaging modality as a screening method. Additionally, we combined Doppler ultrasound with several values to improve the diagnostic efficacy and to establish a new diagnostic tool.

  16. An Acoustic OFDM System with Symbol-by-Symbol Doppler Compensation for Underwater Communication

    Directory of Open Access Journals (Sweden)

    Tran MinhHai

    2016-01-01

    Full Text Available We propose an acoustic OFDM system for underwater communication, specifically for vertical link communications such as between a robot in the sea bottom and a mother ship in the surface. The main contributions are (1 estimation of time varying Doppler shift using continual pilots in conjunction with monitoring the drift of Power Delay Profile and (2 symbol-by-symbol Doppler compensation in frequency domain by an ICI matrix representing nonuniform Doppler. In addition, we compare our proposal against a resampling method. Simulation and experimental results confirm that our system outperforms the resampling method when the velocity changes roughly over OFDM symbols. Overall, experimental results taken in Shizuoka, Japan, show our system using 16QAM, and 64QAM achieved a data throughput of 7.5 Kbit/sec with a transmitter moving at maximum 2 m/s, in a complicated trajectory, over 30 m vertically.

  17. Doppler-shift estimation of flat underwater channel using data-aided least-square approach

    Directory of Open Access Journals (Sweden)

    Weiqiang Pan

    2015-03-01

    Full Text Available In this paper we proposed a dada-aided Doppler estimation method for underwater acoustic communication. The training sequence is non-dedicate, hence it can be designed for Doppler estimation as well as channel equalization. We assume the channel has been equalized and consider only flat-fading channel. First, based on the training symbols the theoretical received sequence is composed. Next the least square principle is applied to build the objective function, which minimizes the error between the composed and the actual received signal. Then an iterative approach is applied to solve the least square problem. The proposed approach involves an outer loop and inner loop, which resolve the channel gain and Doppler coefficient, respectively. The theoretical performance bound, i.e. the Cramer-Rao Lower Bound (CRLB of estimation is also derived. Computer simulations results show that the proposed algorithm achieves the CRLB in medium to high SNR cases.

  18. Doppler-shift estimation of flat underwater channel using data-aided least-square approach

    Science.gov (United States)

    Pan, Weiqiang; Liu, Ping; Chen, Fangjiong; Ji, Fei; Feng, Jing

    2015-06-01

    In this paper we proposed a dada-aided Doppler estimation method for underwater acoustic communication. The training sequence is non-dedicate, hence it can be designed for Doppler estimation as well as channel equalization. We assume the channel has been equalized and consider only flat-fading channel. First, based on the training symbols the theoretical received sequence is composed. Next the least square principle is applied to build the objective function, which minimizes the error between the composed and the actual received signal. Then an iterative approach is applied to solve the least square problem. The proposed approach involves an outer loop and inner loop, which resolve the channel gain and Doppler coefficient, respectively. The theoretical performance bound, i.e. the Cramer-Rao Lower Bound (CRLB) of estimation is also derived. Computer simulations results show that the proposed algorithm achieves the CRLB in medium to high SNR cases.

  19. An Acoustic OFDM System with Symbol-by-Symbol Doppler Compensation for Underwater Communication

    Science.gov (United States)

    MinhHai, Tran; Rie, Saotome; Suzuki, Taisaku; Wada, Tomohisa

    2016-01-01

    We propose an acoustic OFDM system for underwater communication, specifically for vertical link communications such as between a robot in the sea bottom and a mother ship in the surface. The main contributions are (1) estimation of time varying Doppler shift using continual pilots in conjunction with monitoring the drift of Power Delay Profile and (2) symbol-by-symbol Doppler compensation in frequency domain by an ICI matrix representing nonuniform Doppler. In addition, we compare our proposal against a resampling method. Simulation and experimental results confirm that our system outperforms the resampling method when the velocity changes roughly over OFDM symbols. Overall, experimental results taken in Shizuoka, Japan, show our system using 16QAM, and 64QAM achieved a data throughput of 7.5 Kbit/sec with a transmitter moving at maximum 2 m/s, in a complicated trajectory, over 30 m vertically. PMID:27057558

  20. CAMEX-4 MIPS 915 MHZ DOPPLER WIND PROFILER V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The CAMEX-4 MIPS 915 MHZ Doppler Wind Profiler dataset was collected by the University of Alabama in Huntsville (UAH) Mobile Integrated Profiling System (MIPS),...