Time delay calculation of stress waves using wavelet analysis application in canine edematous lungs

We examined the relationship between stress wave velocities and the lung density. The discrete cubic spline wavelet was used to calculate time delay and frequency characteristics of the wave that is propagated on the surface of 3 canine lungs. The analysis verified previous results ascertaining the linear elastic model. As the vascular volume, extra vascular lung water and lung density increased, the wave velocities were decreased; that is the wave velocities were inversely proportional to the square root of the lung density. The analysis verified the exact time-frequency relationship for the dominant stress wave velocity (i.e., shear or Rayleigh-type surface wave velocity) and showed other transit times besides the previously observed short and long ones are not valid