Assessment of Vasodilation Function in Diabetic Patients via Skin Temperature Variation Signals / 医用生物力学

Objective A program-controlled flexible multi-point temperature measurement device was self developed for collection and analysis of skin temperature signals of diabetic patients and healthy subjects under resting and heating conditions so as to assess vasodilation function of the microcirculation, Methods With reference to the endothelial regulation spectrum of human body, wavelet analysis was performed on skin temperature signals, and the temperature fluctuation amplitudes in diabetic group and healthy control group were compared at different time periods after thermal stimulation. Results The temperature fluctuation amplitude in endothelial spectrum of diabetic group was smaller than that of healthy control group, and the decrease in skin temperature fluctuation after the power-off of thermal stimulation was remarkably smaller than that of control group, indicating that the response to thermal stimulation for diabetic patients was slower. Conclusions Vasodilation function can be quantitatively evaluated by using the fluctuation of skin temperature signals in endothelial spectrum band. Skin temperature monitoring is a potentially easy-implemented method for the health management and early diagnosis of microvascular diseases in diabetic patients.

Impacts of El Niño Southern Oscillation on the dengue transmission dynamics in the Metropolitan Region of Recife, Brazil

ABSTRACT Background: This research addresses two questions: (1) how El Niño Southern Oscillation (ENSO) affects climate variability and how it influences dengue transmission in the Metropolitan Region of Recife (MRR), and (2) whether the epidemic in MRR municipalities has any connection and synchronicity. Methods: Wavelet analysis and cross-correlation were applied to characterize seasonality, multiyear cycles, and relative delays between the series. This study was developed into two distinct periods. Initially, we performed periodic dengue incidence and intercity epidemic synchronism analyses from 2001 to 2017. We then defined the period from 2001 to 2016 to analyze the periodicity of climatic variables and their coherence with dengue incidence. Results: Our results showed systematic cycles of 3-4 years with a recent shortening trend of 2-3 years. Climatic variability, such as positive anomalous temperatures and reduced rainfall due to changes in sea surface temperature (SST), is partially linked to the changing epidemiology of the disease, as this condition provides suitable environments for the Aedes aegypti lifecycle. Conclusion: ENSO may have influenced the dengue temporal patterns in the MRR, transiently reducing its main way of multiyear variability (3-4 years) to 2-3 years. Furthermore, when the epidemic coincided with El Niño years, it spread regionally and was highly synchronized.

Continuous wavelet transform methods for the simultaneous determinations and dissolution profiles of valsartan and hydrochlorothiazide in tablets

ABSTRACT Continuous wavelet transform (CWT) was proposed for the simultaneous determination and dissolution profiles of valsartan (VAL) and hydrochlorothiazide (HCT) in tablets, without the use of a chemical separation procedure. The CWT approach was applied to the original UV spectra and their ratio spectra in the optimal wavelength ranges. After testing several wavelet families, Mexican hat function-CWT and Daubechies7-CWT (mexh-CWT and db7-CWT, respectively) were found to be suitable for the transformation of the original UV spectra. In the following procedure, mexh-CWT and Coiflets3-CWT (coif3-CWT) were found to be appropriate for the signal analysis of ratio spectra (RS) of VAL/HCT and HCT/VAL. Calibration graphs for VAL and HCT were obtained by measuring db7-CWT and mexh-CWT amplitudes in the transformation of the original absorption spectra and RS-coif-CWT and RS-mexh-CWT amplitudes in the transformation of the ratio spectra. The validity and applicability of the proposed CWT methods were evaluated through the analysis of an independent set of synthetic binary mixtures consisting of VAL and HCT. The proposed signal processing methods were then successfully applied to the simultaneous quantitative evaluation and simultaneous dissolution profiles of the related drugs in commercial tablets, with good agreement reported for the experimental results.

Sistema de apoio ao diagnóstico da Doença de Chagas baseado em escalogramas e redes neurais auto-organizáveis / Computer-aided system for diagnosis of Chagas' disease based on scalograms and self-organizing neural networks

INTRODUÇÃO: A Doença de Chagas é uma endemia rural, prevalente em grande parte da América Central e América do Sul e, aproximadamente, metade dos pacientes contaminados com o parasita Trypanosoma cruzi não apresentam sinais clínicos, eletrocardiográficos e radiológicos de envolvimento cardíaco. Este trabalho, entretanto, propõe uma técnica de auxílio ao diagnóstico da Doença de Chagas baseada em sinais de eletrocardiografia, que extrai informações relevantes desses sinais. MÉTODOS: Duas abordagens são estudadas e implementadas. Ambas utilizam sinais de variabilidade da frequência cardíaca (VFC) e classificação por meio de rede neural, mais especificamente, o mapa auto-organizável de Kohonen. A VFC, que reflete a modulação neural autonômica simpática e parassimpática do coração, é avaliada com base em séries contínuas de intervalos RR do ECG convencional registradas durante 5 minutos. Na primeira abordagem, indicadores estatístico-temporais obtidos diretamente dos sinais de VFC são utilizados como entrada da rede neural para treinamento e teste do método de classificação. Na segunda proposta, são utilizados escalogramas wavelet com função de base DoG (derivative of Gaussian) para avaliação dos sinais de VFC. Indicadores obtidos dos escalogramas são utilizados como entrada da rede neural no treinamento e no teste do algoritmo. Os mapas topológicos de Kohonen são utilizados para comparar a capacidade dos indicadores calculados dos sinais de VFC em discriminar pacientes chagásicos cardiopatas, chagásicos indeterminados e indivíduos normais. Os indicadores temporais convencionais e os indicadores escalográficos são comparados. RESULTADOS: Os resultados mostram que os indicadores escalográficos têm poder discriminatório estatisticamente superior aos indicadores temporais convencionais. Em particular, a potência média da densidade de potência do escalograma na banda de altas frequências mostrou ser estatisticamente o indicador de maior poder discriminatório (p < 0,05 para os 3 casos). CONCLUSÃO: A metodologia proposta mostrou-se capaz de distinguir entre indivíduos normais, chagásicos cardiopatas e chagásicos indeterminados. Os índices escalográficos propostos mostraram maior capacidade classificatória que os índices temporais tradicionais.

INTRODUCTION: Chagas' disease is an endemic rural disease prevalent in much of Central America and South America, and approximately half of the patients infected with the parasite Trypanosoma cruzi show no clinical, electrocardiographic and radiological cardiac involvement. This paper, however, proposes a technique for the diagnosis of Chagas' disease based on ECG signals, which extracts relevant information from these signals. METHODS: Two approaches are studied and implemented. Both approaches use heart rate variability (HRV) signals, and classification by a neural network, more specifically, the Kohonen self-organizing map. The HRV, which reflects sympathetic and parasympathetic autonomic neural modulation of the heart, is evaluated based on continuous series of RR intervals, calculated from 5-minute records of conventional ECG. In the first approach, statistical/temporal indexes obtained directly from the HRV signals are used as neural network inputs for training and testing of the classification method. In the second approach, derivative of Gaussian (DoG) wavelet scalograms are used to evaluate the HRV signals. Scalographic indexes are used as neural network inputs for training and testing of the algorithm. Kohonen topological maps are used to compare the ability of these HRV indicators of discriminating between patients with Chagas heart disease, Chagas indeterminate heart disease, and normal subjects. Conventional temporal indicators and indicators obtained from DoG scalograms are compared. RESULTS: Results of the application of the proposed methods to HRV signal databases, and performance comparisons, are presented. The results show that scalographic indicators have superior discriminatory power than conventional time-domain indicators. Based on an analysis of statistical significance, we show that the average power of the high-frequency band of the scalogram power spectral density is the indicator with greatest discriminatory power (p < 0,05 for all 3 cases). CONCLUSION: The proposed method has the ability to discriminate between normal subjects, subjects with Chagas cardiomyopathy, and subjects with the indeterminate form of Chagas' disease. It was observed that scalographic neural networks present greater discrimination ability than temporal neural networks.

Sistema computacional para auxílio ao diagnóstico em exames de tuberculose animal / A computer software system to assist in the diagnosis of animal tuberculosis

The results obtained in evaluating the efficiency of a Neuro-Fuzzy System NEFCLASS (Neuro-Fuzzy Classification) in image classification of cattle tuberculosis, based on its texture features extracted using the wavelet transform are presented. For testing, images of animal tissues diagnosed with tuberculosis were used, as provided by the Tuberculosis Laboratory at the Instituto Biológico de São Paulo. The results of this study can serve as a basis for developing systems for diagnosis aimed at reducing human effort, by automating all or parts of the classification of images, helping lab technicians to sort amongst different pathologies.

Totais decendiais de precipitação pluvial em Campinas, SP: persistência temporal, periodicidades e tendências climáticas / Ten-day rainfall amounts at Campinas, State of São Paulo, Brazil: temporal persistence, periodicities, and climate trends

O objetivo do estudo foi descrever as componentes tendências, periodicidades e persistência temporal presentes nas séries decendiais de precipitação pluvial (PRE) na localidade de Campinas/SP, entre os anos de 1890 e 2009. A aplicação da função auto-correlação e do teste Run permitiu inferir a inexistência de significativas correlações seriais entre os totais decendiais de PRE. Análises espectrais conduzidas no domínio tempo-frequencia não possibilitaram a indicação de significativas periodicidades nos picos de variância do sinal temporal PRE. Com base em métodos não paramétricos e considerando as probabilidades máximas de ocorrência do erro tipo I, usualmente admitidas na literatura (10 e 5 por cento), não houve indicação de marcantes tendências climáticas nas séries analisadas. Contudo, observou-se concentração de casos de tendências de queda a partir do final da época seca regional (mês de agosto) até o início do mês de novembro (pertencente à estação chuvosa). Essa característica pode ser considerada um indício de mudança nos padrões do clima regional no sentido de atraso da retomada da estação chuvosa.

The aim of the study was to evaluate the presence of temporal persistence, periodicals components, and trends within the ten-day rainfall series (PRE), observed during 1890-2009 at the weather station of Campinas, State of São Paulo, Brazil. Based on the autocorrelation function and on the Run test it was observed no significant temporal persistence within the data sample. The spectral analysis carried on the time-frequency domain has shown no remarkable periodicity associated with the variance peaks in the temporal signal under evaluation. Based on non parametric methods and considering the significance levels commonly adopted in the scientific literature (10 and 5 percent) it was detected no important climate trend within the PRE series. However, during the end of the dry season and the beginning of the rainy season it was observed an unexpected high number of decreasing (negative) trends cases that may be an indication of changes in the climatic conditions observed during 1890-2009. This last feature may reveal a delay in the resumption of the rainy season.

An approach to automatically segment the media-adventitia borders in IVUS / Uma associação de técnicas para segmentação automática da fronteira da média-adventícia em IVUS

Por ser capaz de mostrar aspectos morfológicos e patológicos de ateroscleroses, o Ultrassom Intravascular (IVUS) se tornou uma das modalidades de imagens médicas mais confiáveis e empregadas em intervenções cardíacas. As características de sua imagem aumentam as chances de um bom diagnóstico, resultando em terapias mais precisas. O estudo de segmentação da fronteira média-adventícia, dentre muitas aplicações, é importante para o aprendizado das propriedades mecânicas e determinação de algumas medidas específicas (raio, diâmetro, etc.) em vasos e placas. Neste trabalho, uma associação de técnicas de processamento de imagens está sendo proposta para atingir alta acurácia na segmentação da borda média-adventícia. Para tanto, foi feita uma combinação das seguintes técnicas: Redução do Speckle por Difusão Anisotrópica (SRAD), Wavelet, Otsu e Morfologia Matemática. Primeiramente, é usado SRAD para atenuar os ruídos speckle. Posteriormente, é executada Transformada Wavelet para extração das características dos vasos e placas. Uma versão binarizada dessas características é criada na qual o limiar ótimo é definido por Otsu. Finalmente, é usada Morfologia Matemática para obtenção do formato da adventícia. O método proposto é avaliado ao segmentar 100 imagens de alta complexidade, obtendo uma média de Verdadeiro Positivo (TP(%)) = 92,83 ± 4,91, Falso Positivo (FP(%)) = 3,43 ± 3,47, Falso Negativo (FN(%)) = 7,17 ± 4,91, Máximo Falso Positivo (MaxFP(mm)) = 0,27 ± 0,22, Máximo Falso Negativo (MaxFN(mm)) = 0,31 ± 0,2. A eficácia do nosso método é demonstrada, comparando este resultado com outro trabalho recente na literatura.

By being able to show morphological and pathological aspects of atherosclerosis, the Intravascular Ultrasound (IVUS) be¬came one of the most reliable and employed medical imaging modality in cardiac interventions. Its image characteristics in¬crease the chances of a good diagnostic, resulting in a precise therapy. The study of media-adventitia borders segmentation in IVUS, among many applications, is important for learning about the mechanical properties and determining some specific measurements (radius, diameter, etc.) in vases and plaques. An approach is proposed to achieve high accuracy in media-adventitia borders segmentation, by making a combination of different image processing operations: Speckle Reducing Anisotropic Diffusion (SRAD), Wavelet, Otsu and Mathematical Morphology. Firstly, SRAD is applied to attenuate the speckle noise. Next, the vessel and plaque features are extracted by performing Wavelet Transform. Optimal thresholding is car¬ried out by Otsu method to create a binarized version of these features. Then, Mathematical Morphology operations are used to obtain an adventitia shape. The proposed approach is evaluated by segmenting 100 challenging images, obtaining an average of True Positive (TP(%)) = 92.83 ± 4.91, False Positive (FP(%)) = 3.43 ± 3.47, False Negative (FN(%)) = 7.17 ± 4.91, Max False Positive (MaxFP(mm)) = 0.27 ± 0.22, Max False Negative (MaxFN(mm)) = 0.31 ± 0.2. The effectiveness of our approach is demonstrated by comparing this result with another recent work in the literature.

Medical Image Coding Based on Lifting Wavelets Transform and SPIHT / 中国医学物理学杂志

Objective:It proposed a new arithmetic of medical image coding based on the lifting scheme wavelets and the set partitioning in hierarchical trees. Methods: Due to the computational complexity of the traditional wavelet, the lifting scheme, which could speed up the fast wavelet transform, was adopted instead of the traditional wavelet transform. With the comprehensive utilization of SPIHT and arithmetic coding, it could achieve to code medical images. Results: At a range of compression ratio, the peak signal to noise ratio was markedly improved, and it could ensure the quality of the reconstruction of medical image to meet the medical image data storage and transmission needs. Conclusions: The simulation experiments show that at the same bit rate, the peak signal to noise ratio is markedly improved.

Algoritmo híbrido para segmentação do ventrículo esquerdo em imagens de ecocardiografia bidimensional / Hybrid algorithm for segmentation of the left ventricle in two-dimensional echocardiography

Este trabalho apresenta uma técnica para segmentação automática da cavidade ventricular esquerda em ecocardiogramas bidimensionais. O algoritmo realiza a identificação e a extração das bordas do ventrículo esquerdo, que permite a obtenção de parâmetros clínicos utilizados no diagnóstico de diversas patologias cardíacas. O processo de extração de bordas é constituído de três etapas: o pré-processamento, a segmentação e a detecção do contorno. Na etapa de pré-processamento é realizada, primeiramente, a aplicação de um algoritmo de minimização do ruído mediante técnica que utiliza transformada de wavelets, seguida da aplicação de uma técnica de elevação do contraste, que prepara a imagem para a próxima etapa. Na etapa de segmentação é utilizada a técnica de watersheds. Na última etapa, procedimentos de morfologia matemática são utilizados para detecção e extração do contorno. A avaliação do desempenho da técnica apresentada foi realizada por meio da comparação dos resultados obtidos pela segmentação automática do ventrículo esquerdo com os resultados obtidos com segmentação manual, feita por um especialista. Os resultados obtidos foram também comparados com os resultdos de outras técnicas descritas na literatura. Para os testes do algoritmo foram descritas na literatura. Para os testes de algoritmo foram utilizadas 60 imagens de ecocardiogramas bidimensionais de pacientes atendidos no serviço de ecocardiolografia do Hospital Universitário de Brasília. Os resultados experimentais mostraram um bom desempenho do método, mesmo em imagens de baixa qualidade, sendo esses resultados superiores aos de outros métodos apresentados na literatura.

ECG real time monitoring system based on LabVIEW / 医疗卫生装备

This paper introduces an ECG real time monitoring system based on LabVIEW.With Wavelet transformation,the original ECG signals are processed to increase the accuracy of R peak detection.The feature of real time in this system is ensured by the application of simplified algorithm.The result panel offers various types of HRV information in time domain,including numerical and graphical displays which make the data more intuitional and more convenient to obtain.The system runs well in lab and the result is acceptable.

Application of multi-band wavelets to medical image retrieval / 医疗卫生装备

Along with the increasing medical image data,it is imperative to set up an effective system about medical image retrieval.Essentially,the image classification is crucial for medical image retrieval.As a distribution pattern of image gray scale,texture is an important character.Wavelet multi-scale decomposition is essentially multi-channel filtering and its multi-resolution analysis structure is identical with human visual system.So the extraction of texture feature under different resolutions after multi-band wavelets transform is of great benefit to image recognition and image retrieval.Consequently,this paper designs an image classification method based on eight-band wavelet.This method solves the key technology in the medical image retrieval,and it gains very high classification rate.