Ultrasound diagnosis device
View Patent ↗Disclosed is an ultrasound diagnosis device for creating an ultrasound image with a high contrast-to-tissue ratio. Said device sends a transmission pulse to the subject, uses an ultrasound probe to receive echoes reflected from an ultrasound contrast agent injected into the subject, and forms an image. The transmission pulse is sent such that nonlinear interactions between the constituent frequency components of said transmission pulse, as a result of the acoustic nonlinearity of the subject, do not produce sum and difference components in the frequency sensitivity range of the ultrasonic probe as the transmission pulse propagates across the subject.
1. An ultrasound device, comprising:
a transmitter that includes a waveform generator and an amplifier and generates a transmit signal;
an ultrasound probe that converts the transmit signal generated from the transmitter into an acoustic signal to transmit an ultrasound transmit pulse to a subject and receives a reflected echo from the subject; and
a signal processor that performs a signal processing of the received reflected echo,
wherein the transmitter generates the transmit signal so as to make a lower limit frequency of sum frequency components generated in the subject by the nonlinear interaction of acoustic waves of frequency components that form the transmit pulse and an upper limit frequency of a sensitivity frequency band of the ultrasound probe substantially equal, and so as to make an upper limit frequency of difference frequency components generated in the subject by the nonlinear interaction of acoustic waves of frequency components that form the transmit pulse and a lower limit frequency of a sensitivity frequency band of the ultrasound probe substantially equal, and
the signal processor suppresses a linear echo from the subject in the sensitivity frequency band of the ultrasound probe.
2. The ultrasound device according to claim 1 ,
wherein the ultrasound probe has a sensitivity frequency band of a center frequency f pc and a fractional bandwidth of B p and receives a first receive echo R 1 which transmits and receives a first transmit pulse P 1 which is a pulse having a center frequency which is equal to the center frequency f pc and a fractional bandwidth of (2−B p )/2 and
a second receive echo R 2 that transmits and receives a second transmit pulse P 2 which is a pulse obtained by multiplying 1/n where n>0, to an amplitude of the first transmit pulse P 1 on the same scanning line as the first transmit pulse P 1 from the ultrasound probe, and
the signal processor subtracts the first receive echo R 1 and a receive echo R 2 ′ obtained by multiplying n to the amplitude of the second receive echo R 2 to obtain a receive echo R on the scanning line.
3. The ultrasound device according to claim 2 , wherein the sensitivity frequency band of the ultrasound probe is an ultrasound frequency band which is transmittable and receivable by the ultrasound probe.
4. The ultrasound device according to claim 2 , wherein the n is represented by m-th power of 2 when m is an integer.
5. The ultrasound device according to claim 2 , wherein the n is 2.
6. The ultrasound device according to claim 2 , wherein when an amplitude of the first transmit pulse P 1 is P 0 , an amplitude of the second transmit pulse P 2 is P 0 /2.
7. The ultrasound device according to claim 2 , wherein conditions of the first transmit pulse P 1 and the second transmit pulse P 2 are determined based on the center frequency f pc and the fractional bandwidth B p obtained from the sensitivity frequency band of the ultrasound probe.
8. The ultrasound device according to claim 1 , wherein the sensitivity frequency band of the ultrasound probe is an ultrasound frequency band which is transmittable and receivable by the ultrasound probe.
9. An ultrasound device, comprising:
a transmitter that includes a waveform generator and an amplifier and generates a transmit signal;
an ultrasound probe that converts the transmit signal generated from the transmitter into an acoustic signal to transmit an ultrasound transmit pulse to a subject and receives a reflected echo from the subject; and
a signal processor that performs a signal processing of the received reflected echo,
wherein the transmitter generates the transmit signal so as to make a lower limit frequency of sum frequency components generated in the subject by the nonlinear interaction of acoustic waves of frequency components that form the transmit pulse and an upper limit frequency of a sensitivity frequency band of the transmit pulse substantially equal, and so as to make an upper limit frequency of difference frequency components generated in the subject by the nonlinear interaction of acoustic waves of frequency components that form the transmit pulse and a lower limit frequency of a sensitivity frequency band of the transmit pulse substantially equal, and
the signal processor extracts a band component corresponding to the frequency band of the transmit pulse from the reflected echo received by the ultrasound probe, and suppresses a linear echo from the subject in the sensitivity frequency band of the transmit pulse.