JP2007159781A - Ultrasound image diagnostic apparatus and noise removal processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonograph which can generated an ultrasonogram where influence of foreign noise is reduced. <P>SOLUTION: An ultrasound probe 1 is provided with: a first transducer 21a which detects an ultrasonic echo signal of a region to be diagnosed: and a second transducer 21x arranged at a position where the ultrasonic echo signal of the region to be diagnosed is not input. The detection signals of the first transducer 21a and the second transducer 21x are sent to a receiving circuit 23a through a signal wiring 22a, and converted into digital data by an A/D conversion circuit 24a. A subtracting circuit section 25 calculates a difference between digital data obtained from A/D conversion circuits 24a, 24b and 24c and digital data obtained from the A/D conversion circuit 24x. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ultrasonic diagnostic imaging apparatus that obtains an ultrasonic image based on a signal from an ultrasonic probe, and a noise removal method in the ultrasonic diagnostic imaging apparatus.

  In the ultrasonic diagnostic imaging apparatus, an ultrasonic wave is transmitted to the inside of the diagnostic object, the echo is received, and an ultrasonic image such as a tomographic image of the diagnostic object is obtained using the received ultrasonic echo signal. Various kinds of diagnostic information such as the beginning are generated. Transmission and reception of ultrasonic waves are performed using an ultrasonic transducer including an ultrasonic transducer. Usually, a plurality of ultrasonic transducers have a predetermined positional relationship (for example, a one-dimensional array shape) in an ultrasonic probe. Or a two-dimensional array). In general, an acoustic lens for converging the ultrasonic beam is provided on the ultrasonic radiation surface side of the transducer array of the ultrasonic probe. The acoustic lens has a substantially cylindrical shape having a convexly curved surface in the ultrasonic radiation direction.

  A signal from the ultrasonic probe is sent to the ultrasonic diagnostic imaging apparatus main body via a predetermined cable, and an ultrasonic image is generated using a digital signal obtained through processing such as amplification and A / D conversion. . The signal detected by the ultrasonic transducer of the ultrasonic probe is a minute signal, and various noises are superimposed at each stage until the digital signal is obtained. Therefore, the ultrasonic image based on the digital signal is also superimposed with noise. It becomes.

  As a method for removing noise of an ultrasonic image in an ultrasonic diagnostic imaging apparatus, a method described in Patent Document 1 has been proposed. In the method of Patent Document 1, when signals from a plurality of transducers are amplified and added by a plurality of stages of amplifiers, the input and output phases of the amplifiers in the middle of each stage are inverted and added to each of the plurality of signals. It cancels out noise.

  However, this noise removal method is intended for the case where external noise is similarly superimposed on the circuit pattern for processing each input signal, and cancels noise mixed in the power supply and ground of the transducer itself and the circuit for processing each input signal. I can't.

JP-A-7-136161

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an ultrasonic diagnostic imaging apparatus and a noise removal processing method capable of generating an ultrasonic image in which the influence of external noise is reduced.

  An ultrasonic diagnostic imaging apparatus according to the present invention is an ultrasonic diagnostic imaging apparatus that obtains an ultrasonic image based on a signal from an ultrasonic probe, and is disposed in the ultrasonic probe, and an ultrasonic echo signal of a diagnosis target part. , A second transducer disposed in the ultrasonic probe at a position where an ultrasonic echo signal of the diagnosis target is not input, a detection signal from the first transducer, and the A reception signal processing unit for obtaining echo information of the diagnosis target part based on a detection signal from the second transducer.

  According to the present invention, only the external noise can be detected by the second transducer, and an ultrasonic diagnostic image in which the influence of the external noise is reduced can be obtained.

  In the ultrasonic diagnostic imaging apparatus according to the present invention, the ultrasonic probe includes an acoustic lens that converges an ultrasonic echo signal of the diagnosis site, and the second transducer is disposed outside a convergence range of the acoustic lens. Including things. According to the present invention, the second transducer for detecting only external noise can be easily arranged in the ultrasonic probe.

  In the ultrasonic diagnostic imaging apparatus of the present invention, the reception signal processing unit receives a detection signal from each of the first transducer and the second transducer, and outputs each of the reception circuits from an A / D. Subtraction processing for obtaining a difference between an A / D conversion circuit to be converted, an output of the A / D conversion circuit corresponding to the first transducer, and an output of the A / D conversion circuit corresponding to the second transducer And the output of the subtraction processing unit includes echo information of the diagnosis site. According to the present invention, it is possible to reduce an external noise picked up by a cable or an A / D conversion circuit connected to an ultrasonic probe, and further obtain an ultrasonic diagnostic image in which the influence of the noise is reduced.

    The ultrasonic diagnostic imaging method of the present invention is a noise removal method in an ultrasonic diagnostic imaging apparatus that obtains an ultrasonic image based on a signal from an ultrasonic probe, and is a first transducer disposed in the ultrasonic probe. The ultrasonic echo signal of the diagnosis site is detected by the second transducer, and only the external noise is detected by the second transducer disposed in the ultrasonic probe at the position where the ultrasonic echo signal of the diagnosis site is not input. The noise removal is performed by calculating a difference between the detection signal from the first transducer and the detection signal from the second transducer.

  As is apparent from the above description, according to the present invention, it is possible to provide an ultrasonic diagnostic imaging apparatus and a noise removal processing method that can generate an ultrasonic image in which the influence of external noise is reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a functional block diagram of an ultrasonic diagnostic imaging apparatus according to an embodiment of the present invention. 1 includes an ultrasonic probe 1, a reception signal processing unit 2, a digital scan converter (DSC) 3, a display monitor 4, a cine memory 5, a cine memory read control unit 6, a three-dimensional image processing unit 7, and a cine memory. It comprises a write control unit 8, a system control unit 9, an input device 10, a cine memory read address counter 11, and a cine memory write address counter 12.

  The ultrasonic probe 1 converts an electrical signal into an ultrasonic wave and transmits it, receives an ultrasonic wave and converts it into an electric signal, and includes a plurality of ultrasonic transducers. The reception signal processing unit 2 converts the ultrasonic signal received by the ultrasonic probe 1 into a plurality of physically continuous echo information. More detailed configurations of the ultrasonic probe 1 and the reception signal processing unit 2 will be described later.

  The digital scan converter (DSC) 3 converts the received signal into a format for displaying as two-dimensional image information. Specifically, the received signal is converted into a format for displaying on the display monitor 4 as B-mode ultrasonic tomographic image frame data of an arbitrary cross section of the diagnosis site. The display monitor 4 is a display device such as a CRT.

  The cine memory 5 is a memory for recording a plurality of physically continuous echo information. The cine memory read control unit 6 controls reading of echo information recorded in the cine memory. The image processing unit 7 creates image information such as a three-dimensional image by using echo information read from the cine memory 5. The cine memory write control unit 8 writes the image information created by the image processing unit 7 to the cine memory 5. The cine memory read address count 11 and the cine memory write address counter 12 are circuits for generating the address of the cine memory 5.

  The system control unit 9 controls the entire ultrasonic diagnostic imaging apparatus. The input device 10 is for designating various conditions for creating image information such as a three-dimensional image.

  Next, a schematic operation of the ultrasonic diagnostic imaging apparatus shown in FIG. 1 will be described. When obtaining ultrasonic echo information of the diagnosis site, the ultrasonic probe 1 is moved in the direction (scanning direction) perpendicular to the ultrasonic cross section (the surface of the ultrasonic fan 1 sent from the ultrasonic probe 1). A sound echo signal is detected. When the ultrasonic transducers of the ultrasonic probe 1 are arranged in a two-dimensional array, physical movement scanning of the ultrasonic probe 1 is not necessary, and the ultrasonic transducer is scanned.

  The ultrasonic probe 1 transmits an ultrasonic wave (in FIG. 1, the block relating to transmission control is omitted), and receives an ultrasonic signal reflected from the diagnosis site. The received signal processing unit 2 performs signal processing such as amplification and detection, and records it as continuous echo information in the cine memory 5. The echo information recorded in the cine memory 5 is converted into B-mode ultrasonic tomographic image frame data by the digital scan converter 3, and the B-mode ultrasonic tomographic image is displayed on the display monitor 4. The cine memory read control unit 6 reads echo information from successive frames, and the image processing unit 7 creates a B-mode ultrasound image.

  As described above, various types of noise are superimposed on the signal from the ultrasonic probe 1. Next, noise removal processing in the ultrasonic diagnostic imaging apparatus of FIG. 1 will be described. FIG. 2 is a diagram illustrating a schematic configuration of the ultrasonic probe 1 and the reception signal processing unit 2.

  The ultrasonic probe 1 includes first transducers 21a, 21b, and 21c and a second transducer 21x. The first transducers 21a, 21b, and 21c transmit ultrasonic waves toward a diagnosis target and detect an ultrasonic echo signal of a diagnosis target part. Although three transducers 21a, 21b, and 21c are shown in FIG. 2, generally more transducers are arranged in a one-dimensional array or a two-dimensional array.

  The second transducer 21x has the same configuration as the first transducers 21a, 21b, and 21c, and is disposed in the ultrasonic probe 1 at a position where the ultrasonic echo signal of the diagnosis target part is not input. In order to prevent the ultrasonic echo signal of the site to be diagnosed from being input, for example, as shown in FIG. 2, a shielding member 20 that performs acoustic shielding is provided between the second transducer 21x and the diagnosis target. When the ultrasonic probe 1 includes an acoustic lens (not shown) that converges the ultrasonic echo signal of the diagnosis target part, the second transducer 21x may be disposed outside the convergence range of the acoustic lens.

  When the arrangement of the transducers in the ultrasonic probe 1 is performed in this manner, the electromagnetic transducer noise is mixed in the detection signals of the first transducers 21a, 21b, and 21c in addition to the ultrasonic echo signal of the diagnosis site. On the other hand, the second transducer 21x is acoustically separated from the first transformer transducers 21a, 21b, and 21c, and the ultrasonic echo signal of the diagnosis site is not input, so that the detection signal indicates only electromagnetic external noise. It will be a thing.

  The detection signals of the first transducers 21a, 21b, 21c and the second transducer 21x are received signal processing units 2 as signals of a plurality of channels in parallel via the signal wirings 22a, 22b, 22c, 22x of the ultrasonic probe cable 22. Sent to. Electromagnetic external noise mixed through the signal wirings 22a, 22b, 22c, and 22x is almost the same for each detection signal.

  The reception signal processing unit 2 includes reception circuits 23a, 23b, 23c, and 23x, A / D conversion circuits 24a, 24b, 24c, and 24x, a subtraction circuit unit 25, and a digital beamformer circuit 26.

  The reception circuits 23a, 23b, 23c, and 23x receive the detection signals of the first transducers 21a, 21b, and 21c and the second transducer 21x through the signal wirings 22a, 22b, 22c, and 22x. It has a configuration. The reception circuits 23a, 23b, 23c, and 23x may have an amplification function and a filter function. The A / D conversion circuits 24a, 24b, 24c, and 24x convert detection signals received by the reception circuits 23a, 23b, 23c, and 23x into digital data, and have the same function.

  Since the processing circuit at each stage until digital data is obtained is the same for all channels, the noise (mixing power of receiving circuits 23a, 23b, 23c, 23x and A / D conversion circuits 24a, 24b, 24c, 24x) is mixed. The noise mixed in the ground is also almost the same. Therefore, it can be considered that the noise components of the digital data obtained from the A / D conversion circuits 24a, 24b, 24c, and 24x are substantially the same.

  The subtraction circuit unit 25 includes a plurality of subtractors 25a, 25b, and 25c, and obtains a difference between digital data obtained from the A / D conversion circuits 24a, 24b, and 24c and digital data obtained from the A / D conversion circuit 24x. Is. The digital data obtained from the A / D conversion circuits 24a, 24b, and 24c is data in which the ultrasonic echo signals detected by the first transducers 21a, 21b, and 21c and the external noise are superimposed, and the A / D conversion circuit 24x. Since the digital data obtained from is data corresponding only to external noise, the digital data output from the subtractors 25a, 25b, and 25c are the ultrasonic echo signals detected by the first transducers 21a, 21b, and 21c, respectively. It becomes a thing corresponding to.

  Thus, the echo data in which noise is mixed at each point (outputs of the A / D conversion circuits 24a, 24b, and 24c) does not include echo data corresponding to the ultrasonic echo signal in the subtraction circuit unit 25. 23x output data (data having only noise components) is subtracted, echo data not including noise components is output to the digital beamformer circuit 26 at the subsequent stage. In FIG. 2, the difference calculation is performed by the plurality of subtracters 25a, 25b, and 25c corresponding to the respective channels. However, the difference calculation may be performed by reducing the number of subtractors.

  The digital beamformer circuit 26 digitally delay-synthesizes the echo signals of the transducers using the echo data from which the noise component has been removed to generate a synthesized echo signal.

  As described above, by using the ultrasonic probe 1 and the reception signal processing unit 2 as shown in FIG. 2, the ultrasonic probe 1 is mixed in the transducer, ultrasonic probe cable, reception circuit, and A / D conversion circuit. A B-mode image from which noise has been removed can be displayed.

  The ultrasonic diagnostic imaging apparatus of the present invention can remove noise from echo data mixed with noise and can generate an ultrasonic image in which the influence of external noise is reduced. Useful.

Functional block diagram of an ultrasonic diagnostic imaging apparatus according to an embodiment of the present invention The figure which shows schematic structure of the ultrasonic probe and the received signal processing part in the ultrasonic image diagnostic apparatus of embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ultrasonic probe 2 Reception signal processing part 3 Digital scan converter 4 Display monitor 5 Cine memory 6 Cine memory reading control part 7 Puncture needle image processing part 8 Cine memory writing control part 9 System control part 10 Input device 11 Cine memory reading address counter 12 Cine memory writing address Counter 20 Shielding member 21a, 21b, 21c First transducer 21x Second transducer 22 Ultrasonic probe cables 22a, 22b, 22c, 22x Signal wiring 23a, 23b, 23c, 23x Receiving circuits 24a, 24b, 24c, 24x A / D conversion circuit 25 Subtraction circuit units 25a, 25b, 25c Subtractor 26 Digital beam former circuit

Claims (4)

An ultrasound diagnostic imaging apparatus that obtains an ultrasound image based on a signal from an ultrasound probe,
A first transducer disposed within the ultrasonic probe and detecting an ultrasonic echo signal of a diagnosis site;
A second transducer disposed in the ultrasonic probe at a position where an ultrasonic echo signal of the diagnosis site is not input;
An ultrasonic diagnostic imaging apparatus comprising: a received signal processing unit that obtains echo information of the diagnosis target part based on a detection signal from the first transducer and a detection signal from the second transducer. The ultrasonic diagnostic imaging apparatus according to claim 1,
The ultrasonic probe includes an acoustic lens that converges an ultrasonic echo signal of the diagnosis site,
The ultrasonic image diagnostic apparatus, wherein the second transducer is disposed outside a convergence range of the acoustic lens. The ultrasonic diagnostic imaging apparatus according to claim 1 or 2,
The reception signal processing unit includes a reception circuit that receives detection signals from the first transducer and the second transducer, an A / D conversion circuit that performs A / D conversion on the output of the reception circuit, and A subtraction processing unit that obtains a difference between the output of the A / D conversion circuit corresponding to the first transducer and the output of the A / D conversion circuit corresponding to the second transducer; An ultrasonic diagnostic imaging apparatus for performing echo information of the diagnosis site. A noise removal method in an ultrasonic diagnostic imaging apparatus that obtains an ultrasonic image based on a signal from an ultrasonic probe,
An ultrasonic echo signal of a diagnosis site is detected by a first transducer disposed in the ultrasonic probe;
Only the extraneous noise is detected by the second transducer arranged in the ultrasonic probe at a position where the ultrasonic echo signal of the diagnosis site is not input,
A noise removal method for removing noise by performing a difference operation between a detection signal from the first transducer and a detection signal from the second transducer.

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