Patent ID: 6358206
Filing Date: 2002-03-19
Classification: A61B,G01S

Abstract:
An ultrasound process for the determination of the location of a local discontinuity of ultrasonic homogeneity forming a parietal surface situated in a tissue, including a step for the acquisition of a radio-frequency signal (y(z)) representing amplitudes of echoes which are returned by tissue scatterers as functions of their digital depths along an excitation line (Z) crossing the parietal surface, and are transmitted by a transducer coupled to the tissue and associated with an ultrasound apparatus,the process also comprising steps for the determination of the parietal surface digital depth on the excitation line, wherein: the radio-frequency signal is filtered so as to provide a tissue signal (e(z)) representative of the tissue scatterers, apart from the radio-frequency excitation signal, the tissue signal (e(z)) is filtered so as to provide a variance amplitude signal (S(z)) as a function of the digital depths on the excitation line, on the basis of which the location of the parietal surface is detected and the corresponding parietal surface digital depth on the excitation line is determined, wherein the filtering of the radio-frequency signal is carried out while using a one-step predictive filter, wherein the one-step predictive filtering operation is carried out while scanning the excitation line, in order to provide, at a given depth (n), a sample (y(n)) of the radio-frequency signal which is a linear function on the one hand of the samples previously determined by said scanning which is representative of the radio-frequency excitation signal (p(n)), and on the other hand of a prediction error (e(n)) which is representative of the tissue scatterers.