Mean scatterer space estimation from ultrasound signals combining singular spectral analysis and entropy

AbstractIntroduction: Ultrasound (US) is a nonionizing radiation capable of real time imaging at low cost. Its most attractive application is quantitative tissue characterization with the objective of differentiating normal tissues from diseased tissues. In this study, an automated method using singular spectrum analysis (SSA) to estimate the mean scatterer space (MSS) of US signals is proposed. Methods Entropy was used to determine the optimal number of components for the SSA. Subsequently, this number was compared with the results using a fixed number of components. A method based on the spectrum of the original signal was also used for comparison. The method was evaluated by using 24,000 simulated US signals, i.e., echoes and jitters backscattered from samples with different ratios of regular-to-irregular structure, as well as with 152 signals obtained from a phantom made of nylon wires. Results For the simulated signals, the proposed method for estimating the MSS presented results similar to the other methods that were tested. However, the magnitude-of-the-spectrum method loses the phase information, and hence, does not allow the characterization of irregular structures. For the signals recorded from the phantom, the methods using SSA and entropy achieved better results. Conclusion In this study, the combination of SSA with entropy to estimate the MSS of a periodic or quasi-periodic medium was proposed. The proposed method achieved similar or better results compared with two other methods found in the scientific literature. The novelty of the proposed method is the application of entropy as a quantitative criterion for selecting the SSA periodic components, allowing it to become independent of heuristic criteria.

Comparative study of periodicity estimation methods using ultrasonic signals

Abstract Introduction Various signal-processing techniques have been proposed to extract quantitative information about internal structures of tissues from the original radio frequency (RF) signals instead of an ultrasound image. The quantifiable parameter called the mean scatterer spacing (MSS) can be useful to detect changes in the quasi-periodic microstructure of tissues such as the liver or the spleen, using ultrasonic signals. Methods We evaluate and compare the performance of three classic methods of spectral estimation to calculate the MSS without operator intervention: Tufts-Kumaresan, SAC (Spectral Autocorrelation) and MUSIC (MUltiple SIgnal Classification). Initially the evaluations were performed with 10,000 signals simulated from a model in which the variables of interest are controlled, and then, real signals from sponge phantoms were used. Results For the simulated signals, the performance of all three methods decreased with increasing Ad or jitter levels. For the sponges, none of the methods accurately estimated the pore size. Conclusion For the simulated signals, Tufts-Kumaresan had the lowest performance, whereas SAC and MUSIC had similar results. For sponges, only Tufts-Kumaresan was able to detect the increase in the size of the pores of the sponge, although most often, it estimated sizes larger than expected.

Paratecnicidade Pré-Intermissiva / Pre-Intermissive Paratechnicity / Paratecnicidad Pre-Intermisiva

Este artigo tem por objetivo discutir a importância da autoqualificação durantea pré-intermissão através do uso planejado da Paratecnologia. O líder assistencialprecisa qualificar-se energeticamente, psicossomaticamente e mentalsomaticamentepara conseguir realizar resgates extrafísicos de compassageiros do passado commaior taxa de êxito, através da paratecnicidade e do planejamento do tempo pré-intermissivo. O artigo ressalta a postura técnica necessária para otimizar o tempopré-intermissivo, aumentar o domínio do psicossoma e das energias, mantendoa prevalência da atuação pelo mentalsoma, promovendo o rapport assistencial semacumpliciamentos, e mantendo o exemplarismo evolutivo teático. Os métodos depesquisa utilizados foram a análise de revisão bibliográfica de técnicas conscienciológicase a migração metodológica da gestão de projetos no paradigma da ciênciaconvencional para a Conscienciologia. A pesquisa foi realizada entre o período deprimeiro de agosto de 2013 a 31 de janeiro de 2014(AU)

The objective of this article is to discuss the importance of self-qualificationduring pre-intermission by the planned use of Paratechnology. The interassistencialleader must qualify himself energetically, psicossomaticly and mentalsomaticly forachieving extraphysical rescues of past co-passengers with greater success rates, byusing paratechnicity and pre-intermission planning time. The article emphasizes theneed optimize pre-intermission time, improve psicossoma and energy control, whilemantaining the prevalence of performance by mentalsoma, promoting the assistencialrapport without accomplicing, while mantaining the teatical-evolutionaryexemplarism. The research methods used were the literature review of constientiologictechniques and the methodological migration of project management from theconventional science paradigm to Conscientiology. The research was done betweenthe period of august 1, 2013, to january 31, 2014(AU)

Este artículo tiene por objetivo discutir la importancia de la autocalificacióndurante la pre intermisión través del uso planeado de Paratecnología. El líder asistencialnecesita cualificarse energéticamente, psicosomaticamente e mentalsomaticamentepara lograr realizar los rescates extrafísicos de compañeros del pasado con mayor índice de éxito, a través de la paratecnicidad y del planeamiento del tiempode preintermisión. El artículo resalta la postura técnica necesaria para optimizar eltiempo pre-intermisivo, aumentar el dominio del psicosoma y de las energías, manteniendola prevalencia de actuación por el mentalsoma, promoviendo el rapportasistencial sin acomplicidades, y manteniendo el ejemplarizo evolutivo teático. Losmétodos de investigación utilizados fueran el análisis de revisión bibliográfica detécnicas conscienciológicas e la migración metodológica de la gestión de proyectosen el paradigma de la ciencia convencional para la Concienciologia. La investigaci-ón fue realizada entre el periodo del primer de agosto de 2013 a 31 de enero de2014(AU)

Depressive symptoms and sleep: a population-based polysomnographic study.

The goals of the present study were to determine the prevalence of depression in the adult population of Sao Paulo, Brazil and to explore the relationship among sociodemographic, physical and psychological factors, sleep-related symptoms and polysomnography parameters. Participants of a cross-sectional study (N = 1101) were administered questionnaires and submitted to polysomnography. A score > 20 in the Beck Depression Inventory was used to describe depression. Results revealed that the prevalence of depression was 10.9%. Estimates were higher in women and were significantly higher among housewives, non-workers and individuals with lower education and income. A combination of sleep-related symptoms and impaired quality of life was 2.5 times more frequent among depressed than non-depressed. Co-morbid insomnia and anxiety were positively associated to depressive symptomatology. There were no alterations in the polysomnography parameters, in either group. The occurrence of sleep apnea with values on the apnea-hypopnea index ≥ 5 was similar and frequent in both groups (around 30%). The findings suggest that depressive symptoms were associated with low education, low income, severe comorbid symptomatology, and impaired quality of life. Considering the high prevalence of sleep apnea, these results point to potential social and financial burdens associated with the depressive symptomatology and various sleep diagnoses.

Paratecnogenia Aplicada à Autopesquisa / Paratechnogenics Applied to Self-Research / Paratecnogenía Aplicada a la Autoinvestigación

Considerando a Paratecnologia a área responsável pela sistematização das pesquisasdos fenômenos parapsíquicos e das autopesquisas enquanto sustentáculos daConscienciologia no planeta, os pesquisadores do Colégio Invisível da Paratecnologiaelaboraram este artigo com o objetivo de apresentar métodos de paratecnogenia e deexposição de técnicas autopesquisísticas. O método utilizado partiu da teática pessoalde cada autor no decorrer de seus processos de autopesquisa, utilizando ferramentasexpostas no desenvolvimento do texto. Foi também realizada revisão bibliográfica dotema. São apresentados os argumentos e as fundamentações, evidenciando comoa Paratecnologia contribui para otimizar a evolução de todos e a consecução da maxiproéxisgrupal e, para elucidação, apresenta-se exemplo prático de aplicação. Na conclusãosão tecidas considerações quanto à contribuição da paratecnogenia para ampliara capacidade interassistencial e sustentação de verpons conscienciológicas(AU)

Considering Para-technology the area responsible for systematic research of parapsychicphenomena and self-research while supporting Conscientiology on the planet,the researchers of the Invisible School of Para-technology developed this articlewith the objective of presenting paratechnogenic methods and exposition of self-researchtechniques. The method used was based on the personal theorice of each authorin the course of their self-research processes, using tools exposed in the text. It wasalso performed a bibliographical revision of the theme. The arguments and groundsare presented, evidencing how Para-technology contributes to optimize the developmentand achievement of everyone’s and in-group maxi-existential program execution,and for elucidation, it is presented a practical application example. In the conclusionit weaves considerations with regards the paratechnogenics contribution toenlarge the interassistance capacity and sustentation of conscientiological leading--edge truths(AU)

Considerando la Paratecnología como la área responsable por la sistematizaciónde las investigaciones de los fenómenos parapsíquicos y de las autoinvestigaciones encuanto sustentáculos de la Concienciología en el planeta, los investigadores del Cole gio Invisible de la Paratecnología elaboraron este artículo con el objetivo de presentarmétodos de paratecnogenía y de exposición de técnicas autoinvestigativas. El métodoutilizado partió de la teática personal de cada autor en el recorrer de sus procesos deautoinvestigación, utilizando herramientas expuestas en el desenvolvimiento del texto.Fue también realizada revisión bibliográfica del tema. Son presentados los argumentosy las fundamentaciones, evidenciando como la Paratecnología contribuyepara optimizar la evolución de todos y la consecución de la maxiproexis grupal,y para elucidación, se presenta ejemplo práctico de aplicación. En la conclusión tejeconsideraciones cuanto a la contribución de la paratecnogenía para ampliar la capacidadinterasistencial y sustentación de verpones concienciológicas(AU)

Detecção automática do espaçamento médio de meios periódicos por sinais ultrassônicos retroespalhados / Automatic detection algorithms for mean scatterer space estimation using ultrasound backscattered signals

A interpretação da imagem ultrassônica, por ocorrer de modo visual e qualitativa, traz uma variação inter e intra-observador importante. A adoção de métodos quantitativos é uma forma de diminuir esta dependência. Entre tais métodos está a quantificação do espaçamento médio entre espalhadores (Mean Scatterer Spacing - MSS), que pode ser útil para detectar mudanças na microestrutura quasi-periódica de tecidos como o hepático ou o esplênico. Neste trabalho foram avaliados três métodos clássicos de estimação espectral para cálculo do MSS (sem intervenção do operador): BURG, WIENER e MUSIC. O intuito é comparar suas potencialidades para a estimação automática de espaçamento médio de espalhadores ultrassônicos. Inicialmente as avaliações foram realizadas com 10.000 sinais simulados a partir de um modelo em que se tem controle das variáveis de interesse, e em seguida foram utilizados sinais reais de phantoms de fios de nylon imersos em água. O método de BURG não conseguiu estimar adequadamente o espaçamento em sinais de phantom, tendo apresentado resultados equivalentes aos outros métodos deste trabalho somente para sinais simulados. O método de WIENER para os sinais simulados apresentou resultados de menor percentual de acerto, ficando em segundo lugar, para os sinais dos phantoms. O método de subespaço MUSIC apresentou melhor desempenho global em relação a BURG e WIENER, com resultados de 100% de acerto para o phantom de fio de nylon de 1,2 mm e 91,45% para 0,8 mm considerando uma janela de acerto de 10%.

The interpretation of ultrasound imaging is essentially visual and qualitative, so there are important inter and intra-observer variations. Quantification methods aim at decreasing this dependency. Among those, the quantification of the Mean Scatterer Spacing (MSS) can be useful to detect changes in the microstructure of quasi-periodic tissues, such as liver or spleen. This study evaluated the following methods of spectral estimation for calculating the MSS (without requiring operator intervention): BURG, WIENER and MUSIC. The aim is to compare their potential for automatic estimation of MSS from ultrasonic scattering signals. Initially, the evaluation has been carried out using 10,000 simulated signals, with the aim of studying the behavior of the methods using a model in which the variables of interest can be controlled. Then, the methods have been applied to real signals of nylon phantoms immersed in water. The BURG method could not estimate the spacing of US phantom signals, presenting results similar to the other methods only for simulated signals. The WIENER method for the simulated signals was in second place in terms of percentage of success, when considering signals from the phantoms. The subspace method MUSIC had the best performance from all three methods.

A double-blind, placebo-controlled, crossover study of sildenafil in obstructive sleep apnea.

BACKGROUND: Sildenafil prolongs the action of cyclic guanosine monophosphate and nitric oxide by inhibiting cyclic guanosine monophosphate-specific phosphodiesterase 5. It is largely used for erectile dysfunction, a highly prevalent condition in obstructive sleep apnea. Because nitric oxide promotes upper airway congestion, muscle relaxation, and pulmonary vasodilation, the aim of this study was to establish the impact of a single 50-mg dose of sildenafil on the sleep of patients with severe obstructive sleep apnea. METHODS: Thirteen [corrected] middle-aged men with severe obstructive sleep apnea were consecutively selected for this double-blind, placebo-controlled, crossover study. Exclusion criteria were obesity, cardiovascular and/or respiratory disease, and conditions that interfere with sleep. All-night polysomnography was preceded by a single 50-mg dose of sildenafil or matching placebo randomly administered at bedtime, after a washout period of 1 week. RESULTS: In comparison to placebo, a single 50-mg dose of sildenafil significantly increased the percentage of total sleep time with an arterial oxygen saturation of less than 90% (mean +/- SD, 15.6% +/- 9.6% vs 7.9% +/- 3.3%, [corrected] P < .01), without a difference in the nadir of oxygen desaturation. The mean arterial oxygen saturation also decreased (92.1% +/- 1.9% vs 93.8% +/- 1.3%, P = .03), [corrected] and the desaturation index increased (30.3 +/- 14.5 [corrected] events per hour vs 18.5 +/- 9.1 [corrected] events per hour, P < .001). There was an increase in apnea-hypopnea index (48.1 +/- 20.8 [corrected] events per hour vs 32.3 +/- 11.3 [corrected] events per hour, P = .001), [corrected] involving mostly obstructive events. CONCLUSION: In patients with severe obstructive sleep apnea, a single 50-mg dose of sildenafil at bedtime worsens respiratory and desaturation events.

Integraçäo de detector e classificador de complexos QRS / Integration of detector and classifying of QRS complexes

Este trabalho apresenta a integração e a avaliação conjunta de um detector e um classificador de complexos QRS, desenvolvidos separadamente. O detector foi avaliado com sinais de 47 pacientes, obtendo-se 0,20 por cento de falsos positivos e 0,26 por cento de falsos negativos. O algoritmo de classificação foi desenvolvido com 32 destes sinais, sendo avaliado com os 15 restantes, obtendo-se um índice de 97,84 por cento de classificação correta.

Abstract - This work presents the integration and evaluation of a detector and a classifier of QRS complexes. developed separately. The detector was evaluated using data from 47 patients. giving 0.20% false positives and 0,26% false negatives. The classifier was developed using 32 signals and evaluated with the remaining 15, giving 97,84% correct classification