Wavelet analysis of stress wave propagation in inflated lungs

This study is based on a linear elastic model of lung parenchyma as an elastic half-space with a taut elastic membrane (pleura) in smooth or welded contact with it. Wavelet analysis was used to calculate time delay and frequency character of the wave that is propagated on the surface of 4 excised horse lungs. The cut-off frequency, f/sub 0/ that exists due to a sufficiently high surface tension T, in a layered model of the lung, is verified by the wavelet analysis. The continuous wavelet analysis that was used in this study utilized a Morlet basis. The analysis verified previous results ascertaining the model, and for the first time, showed other modes of propagation beyond the Rayleigh-type surface wave cut-off frequency.