Objetivos: Avaliar as médias das velocidades e Índices Doppler das Artérias Cerebrais Médias (ACM) e Oftálmicas (AO) de tabagistas conforme o tempo de consumo do cigarro em função do sexo. Avaliar as relações entre a ACM e a AO. Métodos: Utilizou-se o método Doppler para a avaliação do Pico de Velocidade Sistólica (PSV), Velocidade Diastólica Final (VDF) e Velocidade Média (VM) na ACM e na AO. Foi realizada a coleta da VM na Artéria Carótida Interna (ICA) para a realização do Índice de Lindegaard (IL). Os Índices de Resistência (IR) e de Pulsatilidade (IP) também foram avaliados em ambos os vasos. O Segundo Pico de Velocidade Sistólica (P2) e a Relação P2/PVS (PR) foram avaliados na AO. As coletas foram realizadas com um intervalo mínimo de duas horas de abstinência ao cigarro (período tardio) e em até 10 minutos após fumar (período recente). Utilizaram-se os testes t de Student para medidas pareadas para avaliar as diferenças entre os períodos tardio e recentes de consumo (avaliação intragrupo) e o teste t de Student para a comparação entre os sexos (avaliação intergrupo). A diferença entre o período tardio e agudo foi expresso em porcentagens para a avaliação do efeito na AO e na ACM. A variação entre as velocidades intra arteriais da AO e da ACM foi estimada utilizando-se os testes ANOVA e Krukal-Walis. Consideramos significância a um nível de α ≤ 0,05 e um intervalo de confiança de 95% para todos os testes. Resultados: O grupo de estudo foi composto por 71 fumantes crônicos (34 homens e 37 mulheres). O PSV, a VDF e a VM mostraram um aumento de velocidade na AO e na ACM em ambos os vasos e sexos depois de fumar. O IR e o IP apresentaram uma diminuição em ambas as artérias depois de fumar com efeito quase exclusivo nas mulheres. O PR não se alterou em função do consumo dos cigarros, mas foi maior nas mulheres em ambos os períodos de consumo. Não houve variação do IL. Conclusões: Houve aumento das velocidades de fluxo após o consumo do cigarro em ambos os vasos e sexos, com a mesma direção de efeito, compatíveis com alterações transitórias e funcionais no leito arterial. Contudo, os achados sugerem que as mulheres apresentam maior resposta hemodinâmica ao consumo de cigarros. / Objectives: To evaluate the mean of Doppler velocities and indices of the Middle Cerebral Arteries (MCA) and Ophthalmic Arteries (OA) in chronic smokers according to the time of cigarette consumption as a function of sex. To evaluate the relations between the Middle Cerebral Artery and the Ophthalmic Artery. Methods: We used the Doppler method for assessing the Peak of Velocity Systolic (PVS), End Diastolic Velocity (EDV) and Mean Velocity (VM) in MCA and OA. MV was collected in the Internal Carotid Artery (ICA) to perform the Lindegaard Index (IL). Resistance Index (RI) and Pulsatility Index (IP) were performed in both arteries. Second Peak of Systolic Velocity (P2) and P2 / PVS (Peak Ratio _ PR) were evaluated only in the AO. The samples were collected with a minimum of two hours of cigarette withdrawal (late period) and up to 10 minutes after smoking (recent period). We used the paired t-test for the comparison between late and recent periods of cigarette consumption (intragroup assessment) and the unpaired t-test for the comparison between sexes (intergroup comparison). The difference between the late and recent period were expressed in percentages for the evaluation of the effect on the AO and the MCA were used. The variation between intra-arterial velocities in the AO and in the ACM was estimated using the ANOVA and Krukal-Walis tests. We considered significance at a level of α ≤ 0.05 and a 95% confidence interval for all tests. Results: The study group was composed by 71 chronic smokers (34 men and 37 women). The PVS, EDV and VM showed a velocity increase in OA and MCA in both sexes after smoking. RI and PI presented a decrease in both Arteries after smoking, with effect almost exclusively in women. PR was not changed after consumption of cigarettes in both sexes, but it was higher in women in both periods of consumption. There was no variation of IL. Conclusions: There was an increase in flow velocities after cigarette consumption in both arteries and sexes, presenting the same direction of effect, compatible with transient and functional alterations in the arterial bed. However, the findings suggest that women have a greater hemodynamic response to cigarette smoking. / Tese (Doutorado)

INTRODUÇÃO: Evidências relevantes acerca dos benefícios da hipotermia terapêutica provieram da utilização de técnicas de resfriamento sistêmico. Essas técnicas, no entanto, podem causar complicações graves que poderiam ser evitadas com métodos de hipotermia encefálica seletiva. O presente estudo objetiva: 1) verificar a viabilidade da hipotermia encefálica exclusiva através de um sistema de resfriamento nasofaríngeo concomitante ao de preservação da temperatura corpórea em suínos e 2) investigar os efeitos da hipotermia encefálica exclusiva nas variáveis fisiológicas sistêmicas e encefálicas. MÉTODOS: Dez suínos híbridos foram submetidos a resfriamento nasofaríngeo durante 60 minutos e subsequente reaquecimento espontâneo. Foram obtidos dados referentes a: pressão arterial média, débito cardíaco, temperatura encefálica, pressão parcial de oxigênio do tecido encefálico (PbtO2, do inglês, pressure of brain tissue O2), velocidade do fluxo sanguíneo nas artérias encefálicas, índice de resistência e índice de pulsatilidade. RESULTADOS: O resfriamento nasofaríngeo associou-se à um decréscimo gradual da temperatura encefálica, que foi mais marcante no hemisfério cerebral esquerdo (p < 0,01). Neste hemisfério, houve redução de 1,47 ± 0,86°C nos primeiros 5 minutos (p < 0,01), 2,45 ± 1,03°C aos 10 minutos e 4,45 ± 1,36°C após 1 hora (p < 0,01). A diferença entre as temperaturas cerebral sistêmica foi 4,57 ± 0,87°C (p < 0,01). As temperaturas centrais (retal, esofágica e da artéria pulmonar), assim como a hemodinâmica encefálica e sistêmica, mantiveram-se estáveis durante o procedimento. Houve diminuição significativa da PbtO2, concomitantemente ao decréscimo da temperatura encefálica. CONCLUSÕES: A indução de hipotermia encefálica exclusiva é possível através de resfriamento nasofaríngeo associado a medidas de preservação da temperatura sistêmica. O resfriamento encefálico exclusivo não influencia as funções hemodinâmicas sistêmicas e encefálicas, contudo reduz significativamente a PbtO2 / INTRODUCTION: Relevant evidences for the use of therapeutic hypothermia derive from studies using whole body cooling methods. These methods can lead to serious complications. To avoid such complications, selective brain cooling methods were developed. The objective of this study was: 1) to verify the feasibility of exclusive brain hypothermia by means of nasopharyngeal cooling along with measures of systemic temperature preservation in an experimental swine model, and 2) to investigate the influence of the exclusive brain cooling on cerebral and systemic hemodynamics as well as on cerebral oxygenation. METHODS: Ten hybrid swine underwent nasopharyngeal cooling for 60 minutes, followed by spontaneous rewarming. A number of physiological variables were monitored: arterial blood pressure, cardiac output, temperature in the right and left cerebral hemispheres, pressure of brain tissue O2, cerebral blood flow velocities, resistance index, and pulsatility index. RESULTS: Nasopharyngeal cooling was associated with decrease in brain temperature, which was more significant in the left cerebral hemisphere (p < 0,01). There was a reduction of 1.47 ± 0.86°C in the first 5 minutes (p < 0.01), 2.45 ± 1.03°C within 10 min, and 4.45 ± 1.36°C after 1 hour (p < 0.01). The brain-core gradient was 4.57 ± 0.87°C (p < 0,001). Rectal, esophageal, and pulmonary artery temperatures, as well as brain and systemic hemodynamics, remained stable during the procedure. PbtO2 values significantly decreased following the brain cooling. CONCLUSION: Achievement of exclusive brain hypothermia is feasible by means of nasopharyngeal cooling associated with measures of systemic temperature preservation. Selective brain cooling does not influence both systemic and cerebral hemodynamics, except PbtO2, which decreased significantly

Abstract The first aim of this randomized, placebo-controlled and double-blind study was to investigate whether low-dose aspirin therapy, started prior to controlled ovarian hyperstimulation, improves ovarian stimulation response, uterine haemodynamics and clinical pregnancy rates in unselected patients who underwent in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI). The second aim was to examine if the maternal serum placental proteome is different in IVF/ICSI pregnancies compared with spontaneous pregnancies, and whether low-dose aspirin modifies maternal serum placental protein expression and uteroplacental haemodynamics during the first half of pregnancy. Finally, the effect of low-dose aspirin therapy on the incidence of hypertensive pregnancy complications among women who became pregnant after IVF/ICSI was investigated. Low-dose aspirin therapy did not increase the number of oocytes retrieved, the total number of embryos or number of top-quality embryos, endometrial thickness or uterine haemodynamics on the day of embryo transfer (ET) or clinical pregnancy rates compared with placebo-treated IVF/ICSI women. On the day of ET, low-dose aspirin did not affect UtA vascular impedance, but the incidence of non-optimal uterine artery haemodynamics (UtA PI&#8805;3.0) was statistically significantly lower (p&#60;0.05) in the aspirin group compared with the placebo group. In the placebo-treated IVF/ICSI patients, maternal serum proteome analysis showed altered protein expression compared with women with spontaneous pregnancies. Between aspirin- and placebo-treated IVF/ICSI patients, proteome analysis showed a unique and distinct pattern of differentially expressed proteins including extra-cellular matrix, complement and transport proteins. At 6 weeks’ gestation, arcuate artery PI and at 18 weeks’ gestation, UtA PI values were lower (p&#60;0.05) in the aspirin group than in the placebo group. In conclusion, low-dose aspirin therapy, when started concomitantly with controlled ovarian hyperstimulation, did not improve ovarian responsiveness, uterine receptivity, pregnancy outcome in unselected IVF/ICSI women or affect UtA vascular impedance on the day of ET. Low-dose aspirin modified the early placentation process and reduced uteroplacental vascular impedance in mid-pregnancy, but did not decrease the incidence of hypertensive pregnancy complications. / Tiivistelmä Keinoalkuisten hedelmöityshoitojen seurauksena keskimäärin reilu kolmannes naisista tulee raskaaksi hoitokertaa kohti. Näissä raskauksissa äidin seerumista määritettyjen istukkaperäisten merkkiaineiden pitoisuuksissa on eroavaisuuksia verrattuna spontaanisti raskaaksi tulleiden naisten seerumipitoisuuksiin ensimmäisen ja toisen raskauskolmanneksen aikana. Pre-eklampsian eli raskausmyrkytyksen riski on myös lisääntynyt. Syyksi arvellaan istukan verisuonipuuston poikkeavaa kehitystä. Pre-eklampsiaan liitetään intravaskulaarisen prostasykliinin ja tromboksaanin epätasapaino, joka johtaa verihiutaleiden aggregaation lisääntymiseen ja verisuonten supistumiseen. Matala-annoksinen asetyylisalisyylihappo (ASA) vähentää tromboksaanituotantoa ja korjaa tromboksaani- ja prostasykliinituotannon epätasapainoa, mutta sen ei ole todettu merkittävästi vähentävän näiden raskauskomplikaatioiden esiintyvyyttä edes riskiryhmillä, kun lääkitys on aloitettu toisen raskauskolmanneksen aikana. Tämän satunnaistetun ja plasebo-kontrolloidun kaksoissokkotutkimuksen tavoitteena oli tutkia keinoalkuisia hedelmöityshoitoja saavilla naisilla matala-annoksisen ASA-hoidon (100 mg/vrk) merkitystä munasarjojen stimulaatiovasteeseen, alkion kiinnittymiseen, istukan muodostumiseen ja kehittymiseen sekä lääkehoidon vaikutusta kohdun, istukan ja sikiön verenkiertoon, kun lääkitys aloitettiin munasarjojen stimulaatiohoidon alkaessa. Lisätavoitteena oli selvittää, onko lapsettomuushoitoja saavien naisten raskauksissa todettavissa spesifinen istukkaproteomiikkalöydös (istukan tuottamat valkuaisaineet) verrattuna spontaanisti raskaaksi tulleisiin naisiin ja voidaanko siihen vaikuttaa matala-annoksisella ASA-hoidolla. Toisena lisätavoitteena oli selvittää matala-annoksisen ASA-hoidon vaikutus pre-eklampsian esiintyvyyteen loppuraskaudessa. Matala-annoksinen asetyylisalisyylihappo (ASA) ei paranna keinoalkuisten hedelmöityshoitojen hoitotuloksia eikä vaikuta kohdun verenkiertoon tai kohdun limakalvon paksuuteen ultraäänellä arvioituna alkion siirtopäivänä. Matala-annoksista ASA-hoitoa käyttäneiden potilaiden ryhmässä todettiin kuitenkin merkitsevästi vähemmän naisia, joilla oli huonoa hoitotulosta keinoalkuisissa hedelmöityshoidoissa ennakoiva korkea molemminpuolinen kohtuvaltimoiden verenvirtausvastus alkion siirtopäivänä verrattuna plasebo-ryhmään. Raskaaksi tulleilla naisilla, jotka käyttivät matala-annoksista ASA-hoitoa, todettiin kohdun verenvirtausvastus matalammaksi alku- ja keskiraskaudessa verrattuna plasebo-ryhmän naisiin. Istukkaproteomiikkatutkimusten mukaan varhaisistukan proteiinituotanto on erilainen keinoalkuisissa raskauksissa verrattuna spontaanisti alkaneisiin raskauksiin ja siihen voidaan vaikuttaa matala-annoksisella ASA-hoidolla. Pre-eklampsian ja sikiön kasvunhidastuman esiintyvyydessä ei ryhmien välillä todettu eroa. Matala-annoksinen ASA-hoito aloitettuna ennen raskautta munasarjojen stimulaatiohoidon alkaessa ei paranna munasarjojen vastetta lapsettomuushoidoissa käytettäville hormonihoidoille, raskauslukuja eikä kohdun verenkiertoa alkion siirtopäivänä. Hoidon todettiin kuitenkin vaikuttavan varhaisistukan kehittymiseen sekä parantavan kohdun verenkierto alku- ja keskiraskaudessa viitaten istukan verisuonipuuston parempaan kehittymiseen. Matala-annoksinen ASA-hoito ei vähentänyt istukkaperäisten raskauskomplikaatioiden esiintymistä.

Au sein des unités de médecine d'urgence, l'état de choc est une condition courante et par le fait même, une cause majeure de mortalité en Amérique du nord. Il est donc essentiel d'en rechercher rapidement les causes. Dans cette recherche, l'évaluation clinique, l'examen des signes vitaux et les tests de laboratoire se révèlent souvent imprécis car ils ne permettent pas d'évaluer de façon optimale le statut hémodynamique des patients instables. Or, le risque d'une évaluation insuffisante de l’état hémodynamique conduit à l'instauration d'un traitement inapproprié dont la conséquence peut être fatale. Une simple surestimation du besoin de remplissage vasculaire peut entraîner des complications telles que l'œdème pulmonaire et inversement, la sous-estimation peut avoir pour conséquence une hypovolémie persistante avec une hypoperfusion ou un état de choc non reconnu susceptible de générer une insuffisance des organes cibles. Actuellement, pour évaluer le statut hémodynamique, les méthodes les plus utilisées sont la pression veineuse centrale (PVC), les cathéters de Swan-Ganz et l’échocardiographie transoesophagienne. Bien que déjà difficiles à réaliser à l’urgence, toutes ces méthodes sont invasives et conservent un potentiel élevé de morbidité. Il existe toutefois des méthodes alternatives valides qui permettent d'obtenir une estimation non invasive de la pression moyenne de l'oreillette droite, entre autre l’échographie sous-costale avec les mesures échographiques de la collapsibilité de la veine cave inférieure (VCI) et les mesures de Doppler échographiques sur la veine hépatique (VH). Il convient cependant de noter que la mesure de la collapsibilité de la VCI n’a pas réussi à devenir un standard d’évaluation de la volémie parce qu’elle reste sujette à plusieurs facteurs confondants.   La mesure du flot de la VH, quant à elle, semble être une option plus intéressante pour mieux évaluer la pression de remplissage de l’oreillette droite. En effet, l'échographie Doppler de la veine hépatique reste donc un instrument potentiellement prometteur qui peut bien refléter les pressions de l’OD et donc de la pression veineuse centrale. Il importe de souligner que pour le patient instable, chaque minute est précieuse et qu’un gain de temps inestimable contribue à éliminer les facteurs susceptibles de compromettre le pronostic vital. L’objectif principal de notre étude, étant la mesure du temps nécessaire pour l’acquisition d’images ; nous avons comparé la durée de l'acquisition d'images entre l'échographie de la VCI et le Doppler de la VH chez des sujets sains. Le temps moyen d'acquisition d'images de la VCI était de 89,1 secondes et de 117,8 pour la VH. La différence de la moyenne de temps était de 28,6 secondes (IC95% -73,2 · +15,8 ; t=1.33, 24 dl ; p=0.196). La différence de délai pour le temps d’acquisition d’images était inférieure à 30 secondes. En pratique, nous pensons que cette différence peut être considérée comme cliniquement acceptable pour une prise de décision rapide. En ce qui concerne le taux d’échec entre les deux techniques, nous n’avons pas trouvé de différence significative : 1 échec pour la VCI et 5 échecs pour la VH avec une différence de 13% (0.133), p=0.09 ; alors que le taux de réussite est le même, soit 25 pour chacune. L’évaluation de la veine hépatique par échographie était faisable, simple et rapide dans la majorité des volontaires sélectionnés dans notre étude. Mots-clés : échographie Doppler, veine cave inférieure, veines hépatiques, état de choc, statut hémodynamique. / Shock is a common condition and a major cause of death in emergency units. Clinical evaluation, vital signs and laboratory tests can lack specificity to identify the cause of shock and do not allow an optimal evaluation of the hemodynamic status of unstable patients. A poor evaluation of the hemodynamic state could lead to inappropriate treatment and the consequence may be fatal. Overestimation of the need for vascular filling can lead to complications such as pulmonary edema; while underestimation may give rise to persistent hypovolemia with hypoperfusion or unrecognized shock resulting in multi-organ failure. The current methods used to assess hemodynamic status are central venous pressure, Swan-Ganz catheters, and trans-esophageal echocardiography. Although already difficult to perform in the emergency department, all of these methods are invasive and retain a high potential for morbidity. However, there are valid alternative methods for obtaining a non-invasive estimate of the average pressure of the right atrium, including subxiphoid ultrasound with measurements of the inferior vena cava (IVC) collapsibility and ultrasound Doppler measurements of the hepatic veins (HV). However, the measurement of the collapsibility of the IVC is subject to several confounding factors and has failed to become a standard of care for evaluating patients’ volemic status. Measuring the flow of the hepatic vein, on the other hand, seems to be a more interesting option for better assessing the filling pressure of the right atrium. Indeed, the Doppler ultrasound of hepatic veins remains a potentially promising instrument that may well reflect the pressures of the right atrium and thus of the central venous pressure. It is important to emphasize that for the unstable patient, every minute is precious and that saving time contributes to eliminate factors likely to compromise the vital prognosis.   The main objective of our study is to measure the time it takes to acquire images. We compared the duration of image acquisition between IVC ultrasound and HV Doppler in healthy volunteers. The average image acquisition time for the IVC and HV was 89.1 and 117.8 seconds respectively. The difference in mean time was 28.6 seconds (95% CI -73.2 · + 15.8, t = 1.33, 24 dL, p = 0.196). The difference for image acquisition time was less than 30 seconds. In practice, we believe that this difference can be considered clinically acceptable for rapid decision-making. Regarding the failure rate between the two techniques, we did not find any significant difference: 1 failure for IVC and 5 failures for HV with a difference of 13% (0.133), p = 0.09; while the success rate is the same, 25 for each. The evaluation of the hepatic vein by ultrasonography was feasible, simple and fast in the majority of volunteers selected in our study. Key words: Doppler ultrasonography, inferior vena cava, hepatic veins, shock, hemodynamic status

O interesse na medição do perfil de velocidade na área de fluidodinâmica tem crescido nos últimos anos devido a evolução das técnicas de medição. Nesse contexto, a técnica ultrassônica tem se destacado por ser não intrusiva, não invasiva e funcionar mesmo em fluidos opacos. Neste trabalho foi investigado a técnica de ultrassom Doppler para medição de perfis de velocidade, utilizando equipamentos ultrassônicos para ensaios-não-destrutivos (END). Tais equipamentos são mais acessíveis do que equipamentos convencionais de medição de velocidade por ultrassom. Também foi proposto o uso da técnica de autocorrelação estendida (EAM), para medição de velocidades além do limite de Nyquist. Essa restrição existe na grande maioria dos medidores, que utilizam a técnica convencional de autocorrelação (ACM). O EAM combina o ACM com o método da correlação cruzada (CCM), outro estimador amplamente conhecido, mas que não é muito utilizado devido a seu alto custo computacional. Desta forma, o EAM consegue medir velocidades maiores com um custo computacional intermediário, que não é tão baixo quanto o ACM e nem tão alto quanto o CCM. Para adquirir e processar os dados obtidos, foi desenvolvido um sistema para aquisição e processamento dos sinais baseado na linguagem LabView. O pulsador ultrassônico END e os estimadores de velocidade por EAM, CCM e ACM foram validados medindo o perfil de velocidade em um cilindro girante, capaz de fornecer velocidades controladas de fácil solução analítica. Os resultados mostram erros médios quadráticos abaixo de 2%, validando o equipamento e a técnica. O EAM também mediu velocidades acima no limite de Nyquist com um desempenho computacional de 9 vezes maior do que o CCM. Na segunda parte deste trabalho, a técnica ultrassônica de medição de velocidade foi aplicada para medição de escoamentos multifásicos em tubulações, tema de grande interesse da indústria de petróleo e gás. Um escoamento vertical líquido-gás-sólido foi analisado com o mesmo equipamento END. Primeiramente, o perfil de velocidade do escoamento liquido-sólido em regime laminar, foi medido e validado utilizando um equipamento Coriolis como referência. Em seguida, foram realizados testes adicionando gás ao escoamento. As velocidades superficiais de líquido e gás foram variadas para gerar os padrões de escoamento tipo bolhas dispersas, intermitente e intermitente aerado. Os resultados foram comparados a imagens de uma filmadora de alta velocidade. Foram obtidos parâmetros como perfil de velocidade das bolhas dispersas, velocidade do filme de líquido e velocidade da mistura dependendo do padrão de escoamento analisado. Assim, a medição de velocidade por ultrassom Doppler, utilizando um equipamento de END, foi aplicado com sucesso em dois problemas de fluidodinâmica. / Interest in knowing the instantaneous velocity profile in fluid dynamics has grown in recent years as new flow visualization techniques are improving. In this context, the ultrasonic Doppler velocity profiler (UVP) has desirable characteristics, as it is non-invasive, works with opaque liquids, and it is portable and easy to install if compared with other velocity profiler methods. In this work, the use of nondestructive ultrasonic devices in the UVP field is investigated. NDT systems are widely available and have lower cost if compared to traditional ultrasonic velocity profiler systems. The use of an extended autocorrelation method (EAM) for ultrasonic velocity estimation beyond Nyquist limit are also evaluated. The Nyquist limit causes a restriction on the maximum measurable velocity of the traditional autocorrelation method (ACM), present in most of ultrasonic velocity profiler systems. EAM combines the ACM technique with cross-correlation method (CCM) which is a well-established velocity estimator that does not suffer with Nyquist limit. However, the technique has a high computational cost that limits real time applications. EAM has the advantage of measure velocities beyond the Nyquist limit but with a lower computational cost than CCM. To evaluate the NDT device and the velocity estimation techniques ACM, CCM and EAM, a data acquisition system and a signal-processing unit based on LabView language were developed. The velocity profile of a rotating cylinder was used to validate all measurements. The techniques ACM, CCM and EAM successfully measured velocities within Nyquist limit with less than 2% deviation, validating the NDT system. EAM also measured velocities beyond Nyquist limit with a computational performance 9 times faster than CCM. The ultrasonic technique was also applied to measure the velocity profile of a multiphase flow in a pipeline, which are of great interest in oil and gas industry. Tests within a multiphase flow composed by different combinations of oil/sand/nylon-particles and gas were conducted in a vertical rig. A high-speed camera was used to validate the measurements. First the ultrasonic velocity profile measured was validated in a liquid-solid flow by using a Coriolis flowmeter as a reference. Next, superficial liquid and gas velocity were controlled to obtain different flow patterns such as bubbly flow and slug flow. The technique measured the bubbles velocity, the mixture velocity and the liquid film velocity depending on the flow pattern. Finally, the ultrasonic NDT system was successfully applied to investigate two different fluid engineering problems.

Conselho Nacional do Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Financiadora de Estudos e Projetos (FINEP) / Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do Paraná / Universidade Tecnológica Federal do Paraná (UTFPR) / Os sistemas de ultrassom para imagens médicas sempre estão em evolução. Na área de imagem Doppler, em que se pode observar o movimento do objeto, principalmente o fluxo sanguíneo, encontram-se algumas técnicas para obtenção de melhor qualidade de imagem. Os principais problemas da técnica Doppler são a complexidade e a quantidade de dados a serem processados para a formação das imagens. Este trabalho buscou avaliar dois métodos para processamento de imagens Doppler. Inicialmente, foram realizados estudos com o beamforming tradicional gerado pela plataforma de pesquisas ULTRA-ORS no laboratório de ultrassom. Após, foram realizados estudos com o equipamento Verasonics Vantage™ utilizando geração de onda de ultrassom planas, plane-wave, com um transdutor linear modelo L11-4v de 128 elementos. Os phantoms utilizados foram o CIRS Doppler String Phantom model 043 e o Doppler Flow Phantoms & Pumping Systems da ATS. Foram implementados algoritmos para reconstrução das imagens em modo B no Matlab® utilizando os métodos delay-and-sum e f-k migration, com a geração de imagens Doppler colorido e Power Doppler. Os dados para geração de imagem modo B com plane-wave foram adquiridos com variação de 1 a 75 ângulos, na faixa entre -8,88° e 8,88°, com passo de 0,24°. Os resultados obtidos com o f-k migration apresentaram maior resolução, com erros de 1,0 % e 0,8 % para as resoluções lateral e axial, respectivamente, enquanto o método DAS apresentou erros de 12,0 % para resolução lateral e 10,0 % para resolução axial. Para geração das imagens Doppler com plane-wave os dados foram adquiridos com variação de 1 a 21 ângulos, na faixa entre -15,0° e 15,0°, com passo de 1,5°. A estimação da velocidade através da técnica Doppler apresentou melhores resultados utilizando-se o método DAS, com erro de 8,3 %, enquanto o método f-k migration apresentou erro de 16,6 %. Analisando-se os resultados obtidos, foi possível verificar que a técnica plane-wave permite a geração de imagens com maior taxa de quadros por segundo do que os métodos tradicionais. Também pode se observar que o método f-k migration gera imagens de maior qualidade com menor número de ângulos de aquisição, cerca de 9 ângulos, porém possui pior desempenho para geração de imagens Doppler quando comparado ao DAS. / The medical ultrasound equipment is always evolving. In the field of Doppler imaging, which object movement and mainly blood flow of vessels can be measured, there are some techniques to improve image quality. The main problems of the Doppler technique are the complexity and the amount of data to be processed for the image reconstruction. The aim of this work was to evaluate two methods for Doppler images processing. Initially, studies were carried out with the traditional beamforming technique, generated by the research platform ULTRA-ORS in the ultrasound laboratory. Then, with the Verasonics Vantage™ equipment, it was generated ultrasound plane waves with a linear transducer L11-4v of 128 elements. Two Doppler phantoms were used, the CIRS Doppler String Phantom model 043 and the Doppler Flow Phantoms & Pumping Systems from ATS. Algorithms for B mode image reconstruction were developed in Matlab® using the methods Delay-and-Sum and f-k Migration to generate Color Doppler and Power Doppler images. The B mode images with plane-wave were generated from the data acquired with 1 to 75 angles, ranging from -8.88° to 8.88° and 0.24º step. The f-k migration’s results presented higher resolutions than DAS method, with errors of 1.0 % and 0.8 % for lateral and axial resolutions, respectively, while the DAS method presented errors of 12.0 % for lateral resolution and 10.0 % for axial resolution. The data for color Doppler images with plane-wave generation were acquired with 1 to 21 angles, ranging from -15.0° to 15.0°and 1.5° step. The Doppler velocity estimation using the DAS method showed better results (error of 8.3 %) than the f-k migration (error of 16.6 %). Analyzing the obtained results, it was possible to see that the plane wave imaging technique allows the improvement of the frame-rate, being faster than traditional methods. Additionally, it was verified that f-k migration method produces images with better quality using less steering angles, approximately 9 angles, but it shows worse performance when generating Doppler images.

yes / To determine whether jugular venous reflux (JVR) is associated with cerebral white matter changes (WMCs) in individuals with Alzheimer's disease (AD), we studied 12 AD patients 24 mild cognitive impairment (MCI) patients, and 17 elderly age- and gender-matched controls. Duplex ultrasonography and 1.5T MRI scanning was applied to quantify cerebral WMCs [T2 white matter (WM) lesion and dirty-appearing-white-matter (DAWM)]. Subjects with severe JVR had more frequently hypertension (p = 0.044), more severe WMC, including increased total (p = 0.047) and periventricular DAWM volumes (p = 0.008), and a trend for increased cerebrospinal fluid volumes (p = 0.067) compared with the other groups. A significantly decreased (65.8%) periventricular DAWM volume (p = 0.01) in the JVR-positive AD individuals compared with their JVR-negative counterparts was detected. There was a trend for increased periventricular and subcortical T2 WMC lesion volumes in the JVR-positive AD individuals compared with their JVR-negative counterparts (p = 0.073). This phenomenon was not observed in either the control or MCI groups. In multiple regression analysis, the increased periventricular WMC lesion volume and decreased DAWM volume resulted in 85.7% sensitivity and 80% specificity for distinguishing between JVR-positive and JVR-negative AD patients. These JVR-WMC association patterns were not seen in the control and MCI groups. Therefore, this pilot study suggests that there may be an association between JVR and WMCs in AD patients, implying that cerebral venous outflow impairment might play a role in the dynamics of WMCs formation in AD patients, particularly in the periventricular regions. Further longitudinal studies are needed to confirm and validate our findings.