Ultrasonic imaging device
An ultrasonic imaging device for transmitting/receiving ultrasonic pulses to/from a living body in which microbubbles for contrast are introduced and forming a contrast image of the inside of the living body by using the microbubble for contrast, wherein transmitting/receiving operations are performed N times (N=an integer of three or greater) by using transmission pulse waves having a common envelope signal while varying carrier waves in phase by 360°/N from one wave to another under the same transmission/reception wave focus condition, and by summing N pieces of time-series reception echo signals obtained by the N times of transmitting/receiving operations to obtain a summed signal, thereby forming the contrast image.
1. An ultrasonic imaging device for transmitting/receiving ultrasonic pulse to/from a living body in which microbubbles for contrast are introduced, and forming a contrast image of the inside of the living body, comprising:
a transmit beamformer for generating a transmit pulse;
a receive beamformer for generating a time-series reception echo signal with adding receive signals, to each of which a delay time is given for generating receiving sensitivity having directivity;
an adder for summing the time-series reception echo signals; and
a transmit/receive sequence controller for controlling the transmit beamformer and the receive beamformer;
wherein the transmit/receive sequence controller controls the transmit beamformer and the receive beamformer to perform transmitting/receiving operations N times (N=an integer of three or greater) by controlling N pieces of transmission pulse waves having a common envelope signal and different waveforms under a transmission/reception wave focus condition, and controlling carrier waves of the transmission pulse waves so to vary in phase by 360°/N from one wave to a next wave, and receiving returned ultrasonic waves as N pieces of the time-series reception echo signals; and
wherein said adder sums the N pieces of the time-series reception echo signals so at to output an output signal as a signal indicative of a spatial distribution of the microbubbles.
2. The ultrasonic imaging device according to claim 1 , wherein the adder includes a band pass filter for eliminating noise components and outputting said signal indicative of the spatial distribution of the microbubbles as the output signal.
3. The ultrasonic imaging device according to claim 1 , wherein the output signal of the adder obtains transmission/reception sensitivity to an ultrasonic echo signal from the microbubbles with suppressing transmission/reception sensitivity to components form a fundamental wave to a harmonic wave of the ultrasonic echo signal from a soft tissue in the living body.
4. The ultrasonic imaging device according to claim 3 , wherein the components to be suppressed are the components from the fundamental wave to the (N−1)th-order harmonic wave of an ultrasonic echo signal from the soft tissue in the living body.
5. The ultrasonic imaging device according to claim 1 , wherein an amplitude of a sum signal of N pieces of transmission pulse waves is smaller than an amplitude of each of the N pieces of transmission pulse waves.
6. The ultrasonic imaging device according to claim 1 , wherein a signal indicative of a position and a form of the soft tissue in the living body is obtained based on a part of the received signals.
7. The ultrasonic imaging device according to claim 6 , wherein the signal indicative of the position and the form of the soft tissue in the living body is obtained from a part of the time-series reception echo signals.