952 resultados para Echo Cancellation
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OBJECTIVE: The purpose of this study is to evaluate the impact of transeophageal echocardiography on management of patients at low-risk for cardiogenic embolism to prevent new potential cardiovascular sources of emboli. METHODS: We studied 69 patients with ischemic stroke at low-risk for cardiogenic embolism. Transeophageal echocardiography was performed to access: left atrium enlargement; communication or aneurysm of the interatrial septum; patent foramen ovale; spontaneous echo contrast or intracavitary thrombi; the presence of intraaortic atherosclerotic plaques or thrombi; significant valvar morphologic alteration or dysfunction; left ventricle enlargement, hypertrophy, or contractile abnormality. Transesophageal echocardiography altered clinical management, and we adopted anticoagulant therapy or another procedure apart from the use of acetylsalicylic acid. RESULTS: Transeophageal echocardiography detected at least one abnormality in 40 cases (58%). Clinical conduct was adjusted after the performance of transesophageal echocardiography in 11 patients (15.9%); anticoagulation was added in 10 cases and surgical correction in one patient. CONCLUSION: Transeophageal echocardiography was a very useful tool in the secondary prevention for stroke in patients at low risk for cardiogenic embolism.
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OBJECTIVE: To evaluate prior mitral surgical commissurotomy and echocardiographic score influence on the outcomes and complications of percutaneous mitral balloon valvuloplasty. METHODS: We performed 459 complete mitral valvuloplasty procedures. Four hundred thirteen were primary valvuloplasty and 46 were in patients who had undergone prior surgical commissurotomy. The prior commissurotomy group was older, had higher echo scores, and a tendency toward a higher percentage of atrial fibrillation. RESULTS: When the groups were compared with each other, no differences were found in pre- and postprocedure mean pulmonary artery pressure, mean mitral gradient, mitral valve area, and mitral regurgitation . Because we found no significant differences, we subdivided the entire group based on echo scores, those with echo scores <=8 and those with echo scores >8 the mitral valve area being higher in the <=8 echo score group 2.06±0.42 versus 1.90±0.40cm² (p=0.0090) in the >8 echo score group. CONCLUSION: Dividing the groups based on echo score revealed that the higher echo score group had smaller mitral valve areas postvalvuloplasty.
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OBJETIVO: Avaliar a associação entre a evolução do desempenho cognitivo e o prognóstico de idosos após compensação de insuficiência cardíaca avançada. MÉTODOS: Selecionados, consecutivamente, 31 pacientes internados com insuficiência cardíaca classe IV da New York Heart Association, com idade > 64 anos (68 ±7) e fração de ejeção < 0,45 (0,38 ± 0,06). Submetidos a testes cognitivos (digit span, digit symbol, letter cancellation, trail making A e B) e teste de caminhada de 6min, 4 dias antes da alta (T1) e 6 semanas após (T2), cujos desempenhos foram comparados pelo teste T. O valor prognóstico dos escores dos testes cognitivos foram analisados pela regressão logística e o valor de maior acurácia dos testes associado com o prognóstico determinado pela ROC curve. RESULTADOS: Após 24,7 meses, 17 (55%) pacientes faleceram. Os desempenhos ao teste de caminhada e maioria dos testes cognitivos melhoraram entre T1 e T2. O escore do digit span entre os sobreviventes variou de 3,9 para 5,2 (p=0,003), permanecendo inalterado entre os que faleceram (4,1para 3,9; p=0,496). Melhora < 0,75 pontos no escore foi associada à mortalidade (risco relativo de 8,1; p=0,011). CONCLUSÃO: Em idosos, após a compensação de insuficiência cardíaca avançada, a ausência de melhora evolutiva do desempenho cognitivo foi associada a pior prognóstico.
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OBJETIVO: Avaliar a correlação e concordância entre medidas ecocardiográficas das dimensões cardíacas, obtidas através do aplicativo Echo off-line (programa para obtenção de medidas de imagens digitalizadas em estação de trabalho dedicada), com as realizadas convencionalmente. MÉTODOS: Estudo transversal, contemporâneo, sendo randomizados 56 pacientes. Através do programa Echo off-line foram mensuradas as medidas ao modo M e 2D ao nível dos ventrículos, do átrio esquerdo e da aorta. Estas medidas foram comparadas às realizadas por outro profissional, através do teste de correlação de Pearson (r), com alfa crítico de 0,05 e pela análise de concordância (Bland e Altman). RESULTADOS: As mensurações realizadas no sistema Echo off-line demonstraram r de 0,85 a 0,98. A análise de concordância mostrou que, para a maioria das medidas, a diferença média entre os métodos foi aproximadamente zero. A variação de valores absolutos não apresentou, em média, significância clínica. O aplicativo Echo off-line permite uma redução de, aproximadamente, 30% no tempo para realização das medidas. CONCLUSÃO: Este trabalho demonstrou a acurácia do programa Echo off-line para mensurar as dimensões cardíacas em estação de trabalho dedicada, podendo ser utilizado rotineiramente nos laboratórios de ecocardiografia.
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Magnetic resonance imaging, diffusion-weighted imaging, image distortions, eddy currents, echo planar imaging
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AbstractBackground:Heart failure with preserved ejection fraction is a syndrome characterized by changes in diastolic function; it is more prevalent among the elderly, women, and individuals with systemic hypertension (SH) and diabetes mellitus. However, in its early stages, there are no signs of congestion and it is identified in tests by adverse remodeling, decreased exercise capacity and diastolic dysfunction.Objective:To compare doppler, echocardiographic (Echo), and cardiopulmonary exercise test (CPET) variables - ergospirometry variables - between two population samples: one of individuals in the early stage of this syndrome, and the other of healthy individuals.Methods:Twenty eight outpatients diagnosed with heart failure according to Framingham’s criteria, ejection fraction > 50% and diastolic dysfunction according to the european society of cardiology (ESC), and 24 healthy individuals underwent Echo and CPET.Results:The group of patients showed indexed atrial volume and left ventricular mass as well as E/E’ and ILAV/A´ ratios significantly higher, in addition to a significant reduction in peak oxygen consumption and increased VE/VCO2 slope, even having similar left ventricular sizes in comparison to those of the sample of healthy individuals.Conclusion:There are significant differences between the structural and functional variables analyzed by Echo and CPET when comparing two population samples: one of patients in the early stage of heart failure with ejection fraction greater than or equal to 50% and another of healthy individuals.
Frequency of Cardiovascular Involvement in Familial Amyloidotic Polyneuropathy in Brazilian Patients
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Background:Familial amyloidotic polyneuropathy (FAP) is a rare disease diagnosed in Brazil and worldwide. The frequency of cardiovascular involvement in Brazilian FAP patients is unknown.Objective:Detect the frequency of cardiovascular involvement and correlate the cardiovascular findings with the modified polyneuropathy disability (PND) score.Methods:In a national reference center, 51 patients were evaluated with clinical examination, electrocardiography (ECG), echocardiography (ECHO), and 24-hour Holter. Patients were classified according to the modified PND score and divided into groups: PND 0, PND I, PND II, and PND > II (which included PND IIIa, IIIb, and IV). We chose the classification tree as the statistical method to analyze the association between findings in cardiac tests with the neurological classification (PND).Results:ECG abnormalities were present in almost 2/3 of the FAP patients, whereas ECHO abnormalities occurred in around 1/3 of them. All patients with abnormal ECHO also had abnormal ECG, but the opposite did not apply. The classification tree identified ECG and ECHO as relevant variables (p < 0.001 and p = 0.08, respectively). The probability of a patient to be allocated to the PND 0 group when having a normal ECG was over 80%. When both ECG and ECHO were abnormal, this probability was null.Conclusions:Brazilian patients with FAP have frequent ECG abnormalities. ECG is an appropriate test to discriminate asymptomatic carriers of the mutation from those who develop the disease, whereas ECHO contributes to this discrimination.
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Magdeburg, Univ., Fak. für Naturwiss., Diss., 2012
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PURPOSE: To determine the value of applying finger trap distraction during direct MR arthrography of the wrist to assess intrinsic ligament and triangular fibrocartilage complex (TFCC) tears. MATERIALS AND METHODS: Twenty consecutive patients were prospectively investigated by three-compartment wrist MR arthrography. Imaging was performed with 3-T scanners using a three-dimensional isotropic (0.4 mm) T1-weighted gradient-recalled echo sequence, with and without finger trap distraction (4 kg). In a blind and independent fashion, two musculoskeletal radiologists measured the width of the scapholunate (SL), lunotriquetral (LT) and ulna-TFC (UTFC) joint spaces. They evaluated the amount of contrast medium within these spaces using a four-point scale, and assessed SL, LT and TFCC tears, as well as the disruption of Gilula's carpal arcs. RESULTS: With finger trap distraction, both readers found a significant increase in width of the SL space (mean Δ = +0.1mm, p ≤ 0.040), and noticed more contrast medium therein (p ≤ 0.035). In contrast, the differences in width of the LT (mean Δ = +0.1 mm, p ≥ 0.057) and UTFC (mean Δ = 0mm, p ≥ 0.728) spaces, as well as the amount of contrast material within these spaces were not statistically significant (p = 0.607 and ≥ 0.157, respectively). Both readers detected more SL (Δ = +1, p = 0.157) and LT (Δ = +2, p = 0.223) tears, although statistical significance was not reached, and Gilula's carpal arcs were more frequently disrupted during finger trap distraction (Δ = +5, p = 0.025). CONCLUSION: The application of finger trap distraction during direct wrist MR arthrography may enhance both detection and characterisation of SL and LT ligament tears by widening the SL space and increasing the amount of contrast within the SL and LT joint spaces.
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Projecte de recerca elaborat a partir d’una estada a la National Oceanography Centre of Southampton (NOCS), Gran Bretanya, entre maig i juliol del 2006. La possibilitat d’obtenir una estimació precissa de la salinitat marina (SSS) és important per a investigar i predir l’extensió del fenòmen del canvi climàtic. La missió Soil Moisture and Ocean Salinity (SMOS) va ser seleccionada per l’Agència Espacial Europea (ESA) per a obtenir mapes de salinitat de la superfície marina a escala global i amb un temps de revisita petit. Abans del llençament de SMOS es preveu l’anàlisi de la variabilitat horitzontal de la SSS i del potencial de les dades recuperades a partir de mesures de SMOS per a reproduir comportaments oceanogràfics coneguts. L’objectiu de tot plegat és emplenar el buit existent entre les fonts de dades d’entrada/auxiliars fiables i les eines desenvolupades per a simular i processar les dades adquirides segons la configuració de SMOS. El SMOS End-to-end Performance Simulator (SEPS) és un simulador adhoc desenvolupat per la Universitat Politècnica de Catalunya (UPC) per a generar dades segons la configuració de SMOS. Es va utilitzar dades d’entrada a SEPS procedents del projecte Ocean Circulation and Climate Advanced Modeling (OCCAM), utilitzat al NOCS, a diferents resolucions espacials. Modificant SEPS per a poder fer servir com a entrada les dades OCCAM es van obtenir dades de temperatura de brillantor simulades durant un mes amb diferents observacions ascendents que cobrien la zona seleccionada. Les tasques realitzades durant l’estada a NOCS tenien la finalitat de proporcionar una tècnica fiable per a realitzar la calibració externa i per tant cancel•lar el bias, una metodologia per a promitjar temporalment les diferents adquisicions durant les observacions ascendents, i determinar la millor configuració de la funció de cost abans d’explotar i investigar les posibiltats de les dades SEPS/OCCAM per a derivar la SSS recuperada amb patrons d’alta resolució.
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Semiotics is hardly known in German business literature and management practice, despite the fact that its methodological approaches to discourse analysis have already been broadly absorbed by management theory in France and the United States. The present contribution points out why the general echo of semiotic theory and its numerous applications to business administration has remained limited so far, especially when compared with its potential for describing and explaining management problems. It is important, then, to show what the object of semiotic research is, independent of any semiotic orientation or school. What tools have been developed so far, and which discourses in business administration were chosen to apply these tools? The problems limiting a broader use of semiotic instruments in business administration are explained in detail, and the research perspectives are illustrated. Die in der deutschsprachigen Betriebswirtschaftslehre (BWL) noch wenig bekannte Semiotik und die in ihrem Rahmen entwickelten methodologischen Ansätze zur Analyse von Diskursen haben insbesondere in Frankreich und in den USA schon eine weite Verbreitung gefunden. Das Echo, auf welches die Semiotik trifft, bleibt im Vergleich zum Beitrag, den sie hinsichtlich der Beschreibung und Erklärung betriebswirtschaftlicher Tatbestände leisten könnte, noch sehr beschränkt - und dies, obwohl ihre grundsätzliche wissenschaftliche Leistungsfähigkeit inzwischen an Hand zahlreicher Beispiele aus dem betriebswirtschaftlichen Bereich belegt werden konnte. Es ist deshalb wichtig und interessant zu zeigen, was der Forschungsgegenstand der Semiotik ist - und zwar unabhängig von den verschiedenen Schulen der Semiotik. Welche Instrumente hat sie entwickelt? Auf welche betriebswirtschaftlichen Diskurse sind diese Instrumente bereits angewandt worden? Zum Schluss werden die Probleme dargestellt, die einen breiteren Einsatz semiotischer Instrumente in der Betriebswirtschaftslehre behindern und dabei auch die verschiedenen Forschungsrichtungen erläutert.
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PURPOSE: To report the diffusion-weighted MRI findings in alveolar echinococcosis (AE) of the liver and evaluate the potential role of apparent diffusion coefficients (ADCs) in the characterisation of lesions. MATERIALS AND METHODS: We retrospectively included 22 patients with 63 AE liver lesions (≥1cm), examined with 3-T liver MRI, including a free-breathing diffusion-weighted single-shot echo-planar imaging sequence (b-values=50, 300 and 600s/mm(2)). Two radiologists jointly assessed the following lesion features: size, location, presence of cystic and/or solid components (according to Kodama's classification system), relative contrast enhancement, and calcifications (on CT). The ADCtotal, ADCmin and ADCmax were measured in each lesion and the surrounding liver parenchyma. RESULTS: Three type 1, 19 type 2, 17 type 3, three type 4 and 21 type 5 lesions were identified. The mean (±SD) ADCtotal, ADCmin and ADCmax for all lesions were 1.73±0.50, 0.76±0.38 and 2.63±0.76×10(-3)mm(2)/s, respectively. The mean ADCtotal for type 1, type 2, type 3, type 4 and type 5 lesions were 1.97±1.01, 1.76±0.53, 1.73±0.41, 1.15±0.42 and 1.76±0.44×10(-3)mm(2)/s, respectively. No significant differences were found between the five lesion types, except for type 4 (p=0.0363). There was a significant correlation between the presence of a solid component and low ADCmin (r=0.39, p=0.0016), whereas an inverse correlation was found between the relative contrast enhancement and ADCtotal (r=-0.34, p=0.0072). CONCLUSION: The ADCs of AE lesions are relatively low compared to other cystic liver lesions, which may help in the differential diagnosis. Although ADCs are of little use to distinguish between the five lesion types, their low value reflects the underlying solid component.
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PURPOSE: To evaluate the feasibility of visualizing the stent lumen using coronary magnetic resonance angiography in vitro. MATERIAL AND METHODS: Nineteen different coronary stents were implanted in plastic tubes with an inner diameter of 3 mm. The tubes were positioned in a plastic container filled with gel and included in a closed flow circuit (constant flow 18 cm/sec). The magnetic resonance images were obtained with a dual inversion fast spin-echo sequence. For intraluminal stent imaging, subtraction images were calculated from scans with and without flow. Subsequently, intraluminal signal properties were objectively assessed and compared. RESULTS: As a function of the stent type, various degrees of in-stent signal attenuation were observed. Tantalum stents demonstrated minimal intraluminal signal attenuation. For nitinol stents, the stent lumen could be identified, but the intraluminal signal was markedly reduced. Steel stents resulted in the most pronounced intraluminal signal voids. CONCLUSIONS: With the present technique, radiofrequency penetration into the stents is strongly influenced by the stent material. Thesefindings may have important implicationsforfuture stent design and stent imaging strategies.
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Experimentally renal tissue hypoxia appears to play an important role in the pathogenesis of chronic kidney disease (CKD) and arterial hypertension (AHT). In this study we measured renal tissue oxygenation and its determinants in humans using blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) under standardized hydration conditions. Four coronal slices were selected, and a multi gradient echo sequence was used to acquire T2* weighted images. The mean cortical and medullary R2* values ( = 1/T2*) were calculated before and after administration of IV furosemide, a low R2* indicating a high tissue oxygenation. We studied 195 subjects (95 CKD, 58 treated AHT, and 42 healthy controls). Mean cortical R2 and medullary R2* were not significantly different between the groups at baseline. In stimulated conditions (furosemide injection), the decrease in R2* was significantly blunted in patients with CKD and AHT. In multivariate linear regression analyses, neither cortical nor medullary R2* were associated with eGFR or blood pressure, but cortical R2* correlated positively with male gender, blood glucose and uric acid levels. In conclusion, our data show that kidney oxygenation is tightly regulated in CKD and hypertensive patients at rest. However, the metabolic response to acute changes in sodium transport is altered in CKD and in AHT, despite preserved renal function in the latter group. This suggests the presence of early renal metabolic alterations in hypertension. The correlations between cortical R2* values, male gender, glycemia and uric acid levels suggest that these factors interfere with the regulation of renal tissue oxygenation.
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A cardiac-triggered free-breathing three-dimensional (3D) balanced fast field-echo projection renal magnetic resonance (MR) angiographic sequence was investigated for in-stent lumen visualization of a dedicated metallic renal artery stent. Fourteen prototype stents were deployed in the renal arteries of six pigs (in two pigs, three stents were deployed). Projection renal MR angiography was compared with standard contrast material-enhanced 3D breath-hold MR angiography. Artifact-free in-stent lumen visualization was achieved with both projection MR angiography and contrast-enhanced MR angiography. These promising results warrant further studies for visualization of in-stent restenosis.