Method of and device for scanning objects by means of ultrasound echography

Claim 1

A method of ultrasound echographic scanning which determines local values of the scatter coefficient in an object comprising the steps of: repeatedly transmitting pulses of ultrasound energy into the object; receiving echographic A-lines which correspond to principal obstacles encountered by the pulses as they propagate through the object; storing an A-line in a memory; (a) determining the power frequency spectrum of a portion of the A-line which corresponds to a selected volume within the object; (b) correcting the power frequency spectrum for the effects of ultrasound diffraction; and (c) further correcting the power frequency spectrum for the effects of attenuation in the object; whereby the corrected power spectrum characterizes the scatter coefficient in the selected volume of the object.

Claim 2

A method of ultrasound echographic scanning which determines local values of the scatter coefficient in an object comprising the steps of: repeatedly transmitting pulses of ultrasound energy into the object; receiving echographic A-lines which correspond to principal obstacles encountered by the pulses as they propagate through the object; storing an A-line in a memory; (a) determining the power frequency spectrum of a portion of the A-line which corresponds to a selected volume within the object; (b) correcting the power frequency spectrum for the effects of ultrasound diffraction; and (c) further correcting the power frequency spectrum for the effects of attenuation in the object; whereby the corrected power spectrum characterizes the scatter coefficient in the selected volume of the object.

Claim 5

A device for scanning an object by means of ultrasound echography to determine local values of the scatter coefficient therein comprising: an ultrasound transducer; transmitter means connected to the transducer which cause repeated transmission of ultrasound signals into the object; receiver means connected to the transducer which receive ultrasound echoes which correspond to principal obstacles of propagation through the object, wherein the receiver means include (a) memory means which store signals which correspond to the echoes along an echographic A-line; (b) power spectrum determination means connected to process the A-line signal from the memory which include, in cascade, selection means which select a portion of the A-line which corresponds to a selected observation depth in the object; Fourier transformer means which calculate the Fourier transform of the selected portion of the A-line; first arithmetic means connected to the output of the Fourier transformation means which calculate the square of the Fourier transform of the selected portion of the A-line; first means which compensate the output of the first arithmetic means for the effects of ultrasonic diffraction in the object; and second means which compensate the output of the first means which compensate for the frequency dependent effects of ultrasonic attenuation in the object; and (c) means which receive the output of the second means which compensate, which display and/or store the scatter function in the object comprising, in cascade, logarithmic converter means and second arithmetic means which determine the scatter function in the selected region from a predetermined functional relationship of the scatter function as a function of frequency.

Claim 6

A device for scanning an object by means of ultrasound echography to determine local values of the scatter coefficient therein comprising: an ultrasound transducer; transmitter means connected to the transducer which cause repeated transmission of ultrasound signals into the object; receiver means connected to the transducer which receive ultrasound echoes which correspond to principal obstacles of propagation through the object, wherein the receiver means include (a) memory means which store signals which correspond to the echoes along an echographic A-line; (b) power spectrum determination means connected to process the A-line signal from the memory which include, in cascade, selection means which select a portion of the A-line which corresponds to a selected observation depth in the object; Fourier transformer means which calculate the Fourier transform of the selected portion of the A-line; first arithmetic means connected to the output of the Fourier transformation means which calculate the square of the Fourier transform of the selected portion of the A-line; first means which compensate the output of the first arithmetic means for the effects of ultrasonic diffraction in the object; and second means which compensate the output of the first means which compensate for the frequency dependent effects of ultrasonic attenuation in the object; and (c) means which receive the output of the second means which compensate, which display and/or store the scatter function in the object comprising, in cascade, logarithmic converter means and second arithmetic means which determine the scatter function in the selected region from a predetermined functional relationship of the scatter function as a function of frequency.