Comparação do cálculo de dose com os algoritmos Analytical Anisotropic Algorithm e Pencil Beam Convolution na patologia de pulmão

Mestrado em Radioterapia.

Endocardite infecciosa e acidente vascular cerebral: mecanismos fisiopatológicos e avaliação ultrassonográfica

Uma das mais graves complicações da endocardite infecciosa é o acidente vascular cerebral isquémico, responsável por uma alta taxa de mortalidade e morbilidade nos países desenvolvidos. Embora não seja o mecanismo dominante, o cardioembolismo é responsável por cerca de 20% dos enfartes cerebrais isquémicos. Sabe-se que o embolismo cerebral afeta mais de 40% dos pacientes com endocardite infecciosa, uma vez que a embolização da vegetação resultante da infeção das estruturas intracardíacas para a circulação arterial pode levar à oclusão das artérias cerebrais, dando origem, assim, a enfarte por ausência de aporte sanguíneo. O desenvolvimento de técnicas não invasivas baseadas na ultrassonografia tem potenciado um amplo estudo destas patologias, quer a nível cardíaco, quer vascular, promovendo uma melhor compreensão dos mecanismos fisiopatológicos que as envolvem. A ecocardiografia e o Doppler transcraniano detêm um papel central, respetivamente, no diagnóstico e predição do risco de fenómenos embólicos em pacientes com endocardite infecciosa e na avaliação inicial, prognóstico e follow-up de um episódio de acidente vascular cerebral.

Global and local detection of liver steatosis from ultrasound

Liver steatosis is a common disease usually associated with social and genetic factors. Early detection and quantification is important since it can evolve to cirrhosis. Steatosis is usually a diffuse liver disease, since it is globally affected. However, steatosis can also be focal affecting only some foci difficult to discriminate. In both cases, steatosis is detected by laboratorial analysis and visual inspection of ultrasound images of the hepatic parenchyma. Liver biopsy is the most accurate diagnostic method but its invasive nature suggest the use of other non-invasive methods, while visual inspection of the ultrasound images is subjective and prone to error. In this paper a new Computer Aided Diagnosis (CAD) system for steatosis classification and analysis is presented, where the Bayes Factor, obatined from objective intensity and textural features extracted from US images of the liver, is computed in a local or global basis. The main goal is to provide the physician with an application to make it faster and accurate the diagnosis and quantification of steatosis, namely in a screening approach. The results showed an overall accuracy of 93.54% with a sensibility of 95.83% and 85.71% for normal and steatosis class, respectively. The proposed CAD system seemed suitable as a graphical display for steatosis classification and comparison with some of the most recent works in the literature is also presented.

Chronic liver disease staging classification based on ultrasound, clinical and laboratorial data

In this work the identification and diagnosis of various stages of chronic liver disease is addressed. The classification results of a support vector machine, a decision tree and a k-nearest neighbor classifier are compared. Ultrasound image intensity and textural features are jointly used with clinical and laboratorial data in the staging process. The classifiers training is performed by using a population of 97 patients at six different stages of chronic liver disease and a leave-one-out cross-validation strategy. The best results are obtained using the support vector machine with a radial-basis kernel, with 73.20% of overall accuracy. The good performance of the method is a promising indicator that it can be used, in a non invasive way, to provide reliable information about the chronic liver disease staging.

Actualities on Nuclear Medicine Applications in Sports Medicine

Aims: This paper aims to address some of the main possible applications of actual Nuclear Medicine Imaging techniques and methodologies in the specific context of Sports Medicine, namely in two critical systems: musculoskeletal and cardiovascular. Discussion: At the musculoskeletal level, bone scintigraphy techniques proved to be a mean of diagnosis of functional orientation and high sensibility compared with other morphological imaging techniques in the detection and temporal evaluation of pathological situations, for instance allowing the acquisition of information of great relevance in athletes with stress fractures. On the other hand, infection/inflammation studies might be of an important added value to characterize specific situations, early diagnose of potential critical issues – so giving opportunity to precise, complete and fast solutions – while allowing the evaluation and eventual optimization of training programs. At cardiovascular system level, Nuclear Medicine had proved to be crucial in differential diagnosis between cardiac hypertrophy secondary to physical activity (the so called "athlete's heart") and hypertrophic cardiomyopathy, in the diagnosis and prognosis of changes in cardiac function in athletes, as well as in direct - and non-invasive - in vivo visualization of sympathetic cardiac innervation, something that seems to take more and more importance nowadays, namely in order to try to avoid sudden death episodes at intense physical effort. Also the clinical application of Positron Emission Tomography (PET) has becoming more and more widely recognized as promising. Conclusions: It has been concluded that Nuclear Medicine can become an important application in Sports Medicine. Its well established capabilities to early detection of processes involving functional properties allied to its high sensibility and the actual technical possibilities (namely those related with hybrid imaging, that allows to add information provided by high resolution morphological imaging techniques, such as CT and/or MRI) make it a powerful diagnostic tool, claiming to be used on an each day higher range of clinical applications related with all levels of sport activities. Since the improvements at equipment characteristics and detection levels allows the use of smaller and smaller doses, so minimizing radiation exposure it is believed by the authors that the increase of the use of NM tools in the Sports Medicine area should be considered.

Estudo e desenvolvimento de eléctrodos de superfície para electrocardiografia

Mestrado em Engenharia Electrotécnica e de Computadores – Ramo Automação e Sistemas.

Does the intake of LC-PUFAS during pregnancy affect the body composition of term neonates? Preliminary results

Background: The effect of the intake of polynsaturated long chain fatty acids (LCPUFAs) during pregnancy on fetal body composition has been assessed by studies using mostly neonatal anthropometry. Their results have been inconsistent, probably because neonatal anthropometry has several validity limitations. Air displacement plethismography (ADP) is a recently validated non-invasive method for assessing body composition in neonates. Objective: To determine the effect of the intake of LCPUFAs during pregnancy on the body composition of term neonates, measured by ADP. Methods: Cross-sectional study of a convenience sample of healthy full-term neonates and their mothers. The diet during pregnancy was assessed using a validated semi-quantitative food frequency questionnaire; Food Processor Plus® was used to convert food intake into nutritional values. Body composition was estimated by anthropometry and measured by ADP using Pea Pod™ Life Measurements Inc (fat mass - FM, fat-free mass and %FM) within the first 72h after birth. Univariate and multivariate analysis (linear regression model) were performed. Results: 54 mother-neonate pairs were included. Multivariate analysis adjusted to the maternal body mass index shows positive association between LCPUFAs intake and neonatal mid-arm circumference (= 0,610, p = 0,019) and negative association between n-6:n-3 ratio intake and neonatal %FM (= -2,744, p=0,066). Conclusion: To the best of our knowledge, this is the first study on this subject using ADP and showing a negative association between LCPUFAs n-6:n-3 ratio intake in pregnancy and neonatal %FM. This preliminary finding requires confirmation increasing the study power with a greater sample and performing interventional studies.

Morfometria do trato vocal por ressonância magnética: simulação de padrões patológicos articulatórios

Introdução – A análise da forma ou morfometria de estruturas anatómicas, como o trato vocal, pode ser efetuada a partir de imagens bidimensionais (2D) como de aquisições volumétricas (3D) de ressonância magnética (RM). Esta técnica de imagem tem vindo a ter uma utilização crescente no estudo da produção da fala. Objetivos – Demonstrar como pode ser efetuada a morfometria do trato vocal a partir da imagem por ressonância magnética e ainda apresentar padrões anatómicos normais durante a produção das vogais [i a u] e dois padrões articulatórios patológicos em contexto simulado. Métodos – As imagens consideradas foram recolhidas a partir de aquisições 2D (Turbo Spin-eco) e 3D (Flash Gradiente-Eco) de RM em quatro sujeitos durante a produção das vogais em estudo; adicionalmente procedeu-se à avaliação de duas perturbações articulatórias usando o mesmo protocolo de RM. A morfometria do trato vocal foi extraída com recurso a técnicas manuais (para extração de cinco medidas articulatórias) e automáticas (para determinação de volumes) de processamento e análise de imagem. Resultados – Foi possível analisar todo o trato vocal, incluindo a posição e a forma dos articuladores, tendo por base cinco medidas descritivas do posicionamento destes órgãos durante a produção das vogais. A determinação destas medições permitiu identificar quais as estratégias mais comummente adotadas na produção de cada som, nomeadamente a postura articulatória e a variação de cada medida para cada um dos sujeitos em estudo. No contexto de voz falada intersujeitos, foi notória a variabilidade nos volumes estimados do trato vocal para cada som e, em especial, o aumento do volume do trato vocal na perturbação articulatória de sigmatismo. Conclusão – A imagem por RM é, sem dúvida, uma técnica promissora no estudo da fala, inócua, não-invasiva e que fornece informação fiável da morfometria do trato vocal.

Ventilação não invasiva durante o exercício em pacientes com DPOC: revisão sistemática com meta-análise

Mestrado em Fisioterapia

Severe stress urinary incontinence: pelvic floor muscle training program

International guidelines recommend a first line therapy in the treatment of female stress urinary incontinence (SUI), the pelvic floor muscle (PFM) training. This case report assesses the effects of the PFM training program in treating women with severe SUI. The urodynamic parameters allow diagnosed intrinsic sphincter deficiency and urethral hypermobility. The subjective and objective parameters were assessed at the beginning and after six-month of PFM training program. This case report confirms the efficiency of the intensive training program in severe SUI. The medical implications of the PFM training as first treatment option reflect favourable individual results and additionally contribute to the selection of the non-invasive treatment, the reduction of the incidence collateral effects, low costs and that does not prevent future treatment options.

A reliable M-mode ultrasound protocol for the assessment of diaphragm motion

Diaphragm is the principal inspiratory muscle. Different techniques have been used to assess diaphragm motion. Among them, M-mode ultrasound has gain particular interest since it is non-invasive and accessible. However it is operator-dependent and no objective acquisition protocol has been established. Purpose: to establish a reliable method for the assessment of the diaphragmatic motion via the M-mode ultrasound.

Enhancing Multimodal Silent Speech Interfaces With Feature Selection

In research on Silent Speech Interfaces (SSI), different sources of information (modalities) have been combined, aiming at obtaining better performance than the individual modalities. However, when combining these modalities, the dimensionality of the feature space rapidly increases, yielding the well-known "curse of dimensionality". As a consequence, in order to extract useful information from this data, one has to resort to feature selection (FS) techniques to lower the dimensionality of the learning space. In this paper, we assess the impact of FS techniques for silent speech data, in a dataset with 4 non-invasive and promising modalities, namely: video, depth, ultrasonic Doppler sensing, and surface electromyography. We consider two supervised (mutual information and Fisher's ratio) and two unsupervised (meanmedian and arithmetic mean geometric mean) FS filters. The evaluation was made by assessing the classification accuracy (word recognition error) of three well-known classifiers (knearest neighbors, support vector machines, and dynamic time warping). The key results of this study show that both unsupervised and supervised FS techniques improve on the classification accuracy on both individual and combined modalities. For instance, on the video component, we attain relative performance gains of 36.2% in error rates. FS is also useful as pre-processing for feature fusion. Copyright © 2014 ISCA.

Ventilação não invasiva com altas pressões pode ser mais eficaz do que com baixas pressões no tratamento da atelectasia pós-operatória de cirurgia cardíaca?

Mestrado em Fisioterapia

Uranium glass in museum collections

Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Conservação e Restauro Área de especialização – Vidro

The effects of clinical support surfaces on pressure as a risk factor in the development of pressure ulcers, from a radiographical perspective: a narrative literature review

Purpose: Pressure ulcers are a high cost, high volume issue for health and medical care providers, having a detrimental effect on patients and relatives. Pressure ulcer prevention is widely covered in the literature, but little has been published regarding the risk to patients in the radiographical setting. This review of the current literature is to identify findings relevant to radiographical context. Methods: Literature searching was performed using Science Direct and Medline databases. The search was limited to articles published in the last ten years to remain current and excluded studies containing participants less than 17 years of age. In total 14 studies were acquired; three were excluded as they were not relevant. The remaining 11 studies were compared and reviewed. Discussion: Eight of the studies used ‘healthy’ participants and three used symptomatic participants. Nine studies explored interface pressure with a range of pressure mat technologies, two studies measured shear (MRI finite element modelling, and a non-invasive instrument), and one looked at blood flow and haemoglobin oxygenation. A range of surfaces were considered from trauma, nursing and surgical backgrounds for their ability to reduce pressure including standard mattresses, high specification mattresses, rigid and soft layer spine boards, various overlays (gel, air filled, foam). Conclusion: The current literature is not appropriate for the radiographic patient and cannot be extrapolated to a radiologic context. Sufficient evidence is presented in this review to support the need for further work specific to radiography in order to minimise the development of PU in at risk patients.