Abstract: A description is given of a method of spectral analysis of a radio frequency ultrasonic signal reflected by a structure subjected to echographic examination, comprising the steps of: a) transmitting an ultrasonic excitation signal into a portion of said structure under examination; b) receiving a radio frequency response signal from said structure; c) applying a time-frequency transform to said radio frequency response signal, dividing the radio frequency response signal into a plurality of frequency bands; d) calculating a local spectral parameter from the values of the time-frequency transform.

Abstract: The method decomposes the radio frequency signal into sub-bands by filtering, for example with a time-frequency transform. From the coefficients acquired through decomposition a matrix of spectral coefficients is obtained, from which local estimators are obtained, constituted in particular by the coefficients of the interpolating polynomials. The statistical distribution of the local estimators is evaluated in windows overlaid on the ultrasound frame. The conformation of the distribution histograms of the spectral coefficients provides a parameter which, combined with the local estimators, provides weighted local estimators, which contain spectral information useful in the identification of specific structures in the organ subjected to ultrasound analysis.

Abstract: What is described is an echographic examination method, in which an echographic contrast medium or agent, injected into a blood vessel and comprising a plurality of microbubbles, is sent by means of the blood circulation to a part of a living body under investigation and said part is struck by an ultrasonic excitation signal at an excitation frequency (f0), and in which the microbubbles struck by the ultrasonic excitation signal generate an echo signal at a frequency different from the excitation frequency, said signal being used to, generate an image. The excitation signal exerts a pressure of 30 kPa to 1 MPa on said microbubbles, the microbubbles emitting a stable signal at not less than one subharmonic of the excitation frequency, said stable signal being processed to generate images.

Abstract: A description is given of a method of spectral analysis of a radio frequency ultrasonic signal reflected by a structure subjected to echographic examination, comprising the steps of: a) transmitting an ultrasonic excitation signal into a portion of said structure under examination; b) receiving a radio frequency response signal from said structure; c) applying a time-frequency transform to said radio frequency response signal, dividing the radio frequency response signal into a plurality of frequency bands; d) calculating a local spectral parameter from the values of the time-frequency transform.