Multi-frequency narrowband tissue characterization

Characterization of the tissue of a thin layer (e.g. an artery wall) can be achieved by comparison of the spectra of the reflections from the boundaries of the tissue layer. To avoid problems that arise from the use of short (broadband) pulses, the method proposed uses long and almost monochromatic pulses. The frequency dependence of the acoustic parameters can be obtained by using different central emission frequencies. A deconvolution algorithm is used to separate overlapping reflections from closely spaced tissue interfaces. A Wiener-inverse filter allows adequate recovery of the temporal resolution, and a deconvolution algorithm based on l₁ deconvolution gives accurate estimates of the reflectivity values, even under noisy conditions