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Tese de Doutorado

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Abstract of Thesis presented to UFSC<br />

as a partial fulfillment of the requirements for the <strong>de</strong>gree of<br />

Doctor in Electrical Engineering<br />

AQUISIÇÃO E PROCESSAMENTO DE SONS CREPITANTES<br />

PARA AUXÍLIO AO DIAGNÓSTICO DE ENFERMIDADES<br />

PULMONARES<br />

Daniel Ferreira da Ponte<br />

Junho/2011<br />

This paper discusses the <strong>de</strong>velopment and implementation of<br />

a system of acquisition of lung sounds of low-cost techniques to<br />

investigate the acquisition and processing of crackling sounds that are<br />

present in patients with cystic fibrosis, pneumonia and congestive heart<br />

failure (CHF). The goal is to capture sounds that carry more diagnostic<br />

information and analyze them to better <strong>de</strong>fine diagnostic criteria<br />

proposed in the literature. Therefore aims to contribute to the<br />

achievement of quantitative parameters that may assist the diagnosis and<br />

monitoring of clinical status of patients. The results showed that using<br />

high-pass filter and allow a<strong>de</strong>quate returns the record sounds with<br />

higher maximum frequency. It also discussed the effect of attenuation<br />

caused by the sound path between the lungs and chest area<br />

compromising the analysis of crackling, because it alters the<br />

morphological and spectral those signals. To recover the signal<br />

subjected to the effect of channel equalization techniques have been<br />

applied FLSI (Fir Least Square Inverse) and EVA (Eigenvector<br />

Approach) and raising the maximum frequency and morphology of<br />

recovering the signal. This work also shows that the use of techniques<br />

and DPWD (Pseudo Discrete Wigner-Ville Distribution) and MGM<br />

(Modified Geometric Method) appropriate to non-stationary signal, the<br />

crackling allows the objective <strong>de</strong>tection of its maximum frequency in<br />

different diseases, enabling the differentiation of patients with fibrosis<br />

and pneumonia among patients with fibrosis and congestive heart<br />

failure. With the technique it was possible to estimate the maximum<br />

frequency higher in the studied illnesses reported in the literature. The<br />

variation of relative volume and respiratory rate measured in these rates<br />

did not change the estimate of the maximum frequency was statistically<br />

significantly so.<br />

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