Abstract
Purpose: Many diseases such as bronchial asthma or pneumonia are detected by chest auscultation with a stethoscope. However, there are no obvious criteria for evaluating the chest auscultation findings. In the present study, chest auscultation findings were evaluated by digital computer analysis.
Material and method: "Crackle" was evaluated among abnormal respiratory sounds. Crackles with very short duration were extracted from recorded respiratory sounds, and FFT (Fast Fourier Transform) analysis was used.
Result: Spike-like waves could be recognized visually in the time-amplitude plot of respiratory sounds. The durations of each crackle ranged between 12.6 and 31.3 msec. The high/low-pitched sound ratio calculated by FFT analysis ranged between 0.059 and 3.24.
Conclusion: The characteristics of crackles could be evaluated objectively by computer analysis. The high/low-pitched sound ratio correlated with the computed tomography (CT) findings and the ratio is useful for differential diagnosis of the disease.
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