Pulse offset ultrasonic imaging
View Patent ↗A diagnostic ultrasound image of a region of interest (ROI) of a body is formed by transmitting into the ROI at least a first and a second ultrasound pulse, in which the second pulse is phase-shifted relative to the first pulse by an amount other than 0 or 180 degrees. Discretized receive signals from the pulses are interleaved to form a resultant operating signal that is detected and beamformed as the operating signal.
1. A method for creating an image of a region of interest of a body comprising:
transmitting a first ultrasonic pulse into the region of interest;
sensing first receive signals corresponding to ultrasonic energy from the first ultrasonic pulse reflected from within the region of interest;
transmitting a second ultrasonic pulse into the region of interest;
sensing second receive signals corresponding to ultrasonic energy from the second ultrasonic pulse reflected from within the region of interest;
creating the image of the region of interest as a function of the first and second receive signals;
interleaving discretized representations of the first and second receive signals to form a resultant operating signal; and
creating the image as a function of the resultant operating signal;
wherein the second ultrasonic pulse is phase-shifted relative to the first ultrasonic pulse by an amount greater than zero degrees and less than 180 degrees, wherein K receive signals, corresponding to echo signals from respective, relatively phase-offset transmitted ultrasonic pulses, are discretized and interleaved to form the resultant operating signal, wherein the K receive signals include at least the first and second receive signals, and wherein:
K is two or greater;
the phase shift is chosen such that the second ultrasonic pulse is transmitted with a time delay of 1/K·f s ; and
the receive signals are discretized with an initial sampling rate of f s .
2. The method of claim 1 , further comprising:
extracting a nonlinear component from the operating signal; and
beamforming the nonlinear component to generate a scan line, whereby a series of scan lines form the image.
3. The method of claim 1 , in which K is greater than two.
4. The method of claim 1 , wherein amplitudes of the K ultrasonic pulses are weighted by corresponding weight coefficients.
5. The method of claim 4 , wherein the weight coefficient for the amplitude of a k th ultrasonic pulse is
cos
(
2
π
(
k
-
1
)
K
·
α
)
,
k
=
1
,
2
…
K
α is positive integer and
the center frequency of the linear component is moved to αf s .
6. The method of claim 5 , wherein the (K, α) is selected from any one of groups of (2, 1) and (6, 2).
7. A system for creating an image of a region of interest of a body comprising:
an ultrasound transducer configured to transmit a first ultrasonic pulse and at least a second ultrasonic pulse into the region of interest;
the ultrasound transducer configured to sense first and second receive signals corresponding to ultrasonic energy from the first and second ultrasonic pulses, respectively, from within the region of interest;
transmit control circuitry configured to provide control signals to the ultrasound transducer to generate the second ultrasonic pulse phase-shifted relative to the first ultrasonic pulse by an amount greater than zero degrees and less than 180 degrees;
reception circuitry configured to create the image of the region of interest as a function of the first and second receive signals;
interleaving circuitry configured to interleave discretized representations of K receive signals to form a resultant operating signal, wherein the K receive signals include at least the first and second receive signals; and
detection and beamforming circuitry configured to create the image as a function of the resultant operating signal;
wherein the phase shift is chosen such that the second ultrasonic pulse is transmitted with a time delay of 1/K·f s ; and
wherein the receive signals are discretized with an initial sampling rate of f s .
8. The system of claim 7 , in which the detection and beamforming circuitry comprises:
a detector configured to extract a nonlinear component from the operating signal for each group of ultrasonic pulses and to generate a resultant of the nonlinear component for each group of transmitted ultrasonic pulses; and
a beamformer configured to beamform the resultant of the nonlinear component for each group of ultrasonic pulses to generate a scan line, whereby a series of scan lines form the image.
9. The system of claim 7 , wherein amplitudes of K ultrasonic pulses are weighted by corresponding weight coefficients, wherein the K ultrasonic pulses include at least the first and second ultrasonic pulses.
10. The system of claim 9 , wherein the weight coefficient for the amplitude of a k th ultrasonic pulse is
cos
(
2
π
(
k
-
1
)
K
·
α
)
,
k
=
1
,
2
…
K
;
α is positive integer; and
the center frequency of the linear component is moved to αf s .