Moving ultrasonic echographic locality exploration apparatus, in particular for the flow of blood or organs such as the heart

Claim 1

An apparatus for scanning moving objects by means of ultrasonic echography, which apparatus comprises a stage for the periodic transmission of ultrasonic pulse signals to the object to be scanned, a stage for receiving and processing echographic signals returned by said object, a circuit for suppressing fixed echoes in order to eliminate those returned signals which correspond to fixed objects within the object being scanned and to select the signals corresponding to the moving objects, a storage, scan conversion and colour encoding device, and a device for the display of flow parameters associated locally with each point of the object scanned, characterized in that it comprises a circuit (330) for estimating flow parameters by correlation of said signals associated with moving objects for two successive emissions of periodic signals, and also comprises a discriminator circuit (360) which itself comprises: - means for selecting a difference signal between signals associated with moving objects for two successive emissions of periodic signals; - means for calculating the local energy as a function of the part of said difference signal which corresponds to each region of the object examined; - means for comparing the energy thus calculated with a predetermined threshold in order to eliminate the estimated flow parameters associated with a given region if said energy is below said threshold.

Claim 3

An apparatus as claimed in any one of the Claims 1 and 2, characterized in that the parameter estimation circuit performs the estimation of the local velocity in the object scanned, the discriminator circuit also comprising means for comparing said local velocity with a predetermined threshold in order to eliminate the locally estimated flow parameters if said velocity is below said threshold.

Claim 4

An apparatus as claimed in any one of the Claims 1 to 3, characterized in that the circuit for estimating flow parameters comprises on the one hand a cross-correlation circuit which supplies, on the basis of said difference signals relating to two successive echographic lines, a given number of correlation function values, and on the other hand an interpolation circuit which supplies, on the basis of said values, parameters which are representative of the velocity of the objects scanned along the axis of propagation of the ultrasonic waves.

Claim 5

An apparatus as claimed in any one of the Claims 1 to 3, characterized in that the circuit for estimating flow parameters comprises on the one hand a cross-correlation circuit which supplies, on the basis of said difference signals relating to two successive echographic lines, three correlation function values, and on the other hand an arithmetic unit which supplies, on the basis of said values, parameters which are representative of the velocity of the objects scanned along the axis of propagation of the ultrasonic waves.

Claim 6

An apparatus as claimed in any one of the Claims 1 to 6, characterized in that it also comprises means for locally suppressing flow parameters when the local estimated velocity in said relevant region is below a predetermined threshold.