JP2006346161A - Ultrasonic diagnostic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To optimize a scan system corresponding to the setting of an ultrasonic condition. <P>SOLUTION: A reception circuit 13 is provided with reception channels composed of amplifiers 31 and delay circuits 32 for the same number as ultrasonic vibrators 11, an adder 33 for adding signals passed through the respective reception channels, and a multiplexer 34 for switching output from the ultrasonic vibrators 11 and inputting it to the reception channels. A control circuit 18 controls the multiplexer 34 so as to respectively send the respective reception signals from the ultrasonic vibrators 11 for a number less than a half of the number of the reception channels to two different reception channels and generate addition signals of signals delayed by the combination of two different delay time periods from the adder 33 when a shallow reception focus is set through a user interface 19, and controls the multiplexer 34 so as to input the reception signals from the respective ultrasonic vibrators 11 to one reception channel respectively when a deep reception focus is set. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ultrasonic diagnostic apparatus that receives ultrasonic waves into a subject and receives reflected waves to obtain data in the subject, and more particularly to an electronic scanning system that includes an ultrasonic probe including an ultrasonic transducer array. The present invention relates to an ultrasonic diagnostic apparatus that controls ultrasonic beam formation.

  Ultrasound diagnostic equipment transmits ultrasonic waves into a subject such as the human body that is a patient, receives ultrasonic waves that are reflected back inside the subject, and reflects the acoustic reflection coefficient and blood flow inside the subject. Data related to Doppler shift or the like due to an object having a certain movement is obtained. In an electronic scanning ultrasonic diagnostic apparatus, an ultrasonic probe that transmits and receives ultrasonic waves is composed of a transducer array in which a large number of ultrasonic transducers such as piezoelectric elements are arranged in a strip shape. Ultrasonic waves are transmitted and received while being in close contact with the subject surface. Then, by controlling the delay time of the ultrasonic frequency pulse applied to each ultrasonic transducer, a synthesized transmission ultrasonic beam is synthesized by synthesizing ultrasonic waves from each transducer in the acoustic medium (subject). Also for reception, an ultrasonic beam is synthesized by giving a controlled delay time to the received signals from the transducers and adding them.

  Referring to FIG. 3, a large number of ultrasonic transducers 11 are arranged to form an array, and a transmission circuit 12 and a reception circuit 13 are connected to each of the ultrasonic transducers 11 in the array. The The transmission circuit 12 is provided with a pulse generator 21 that generates a pulse having an ultrasonic frequency, and this pulse is sent to each of the drive channels including the delay circuit 22 and the drive circuit 23. A drive channel is provided for each transducer 11, and the pulse delayed by the delay circuit 22 is sent to the drive circuit 23, and each of the ultrasonic transducers 11 is pulse-driven by the drive circuit 23.

  By controlling the delay time in the delay circuit 22 of each drive channel, ultrasonic waves are emitted from each transducer 11 in a pulse shape at different timings. These emitted ultrasonic waves are synthesized in the propagation medium (subject), but the pulse applied to each transducer 11 is delayed and the timing of the drive pulse is controlled. The focus of the ultrasonic wave can be determined in the distance direction and the azimuth direction.

  The ultrasonic wave incident on the subject is reflected in the subject, returns to each ultrasonic transducer 11, enters the ultrasonic transducer 11, and a reception signal is generated from each transducer 11. The reception signal from each transducer 11 passes through the reception channel including the amplifier 31 and the delay circuit 32 in the reception circuit 13, and then is added by the adder 33. Also in the receiving circuit 13, the delay time of the delay circuit 32 is controlled, whereby the focus control in the distance direction and the azimuth direction can be performed with respect to the received ultrasonic wave.

By the way, as described in, for example, the following Patent Document 1, two-direction simultaneous reception is performed by simultaneously forming two reception ultrasonic beams adjacent on both sides for one transmission ultrasonic beam ( A technique for increasing the frame rate by performing parallel scan) is known. This is to form two received ultrasonic beams simultaneously by delaying and adding the same received signal obtained from each transducer with a combination of different delay times. That is, with reference to FIG. 4 showing only the receiving circuit 13, two circuits for amplifying, delaying, and adding the received signals from each transducer 11 are provided, and in each system, each received signal of the transducer 11 is provided. Is passed through each channel comprising the amplifier 31a and the delay circuit 32a and input to the adder 33a. In the other system, each received signal of the vibrator 11 is passed through each channel comprising the amplifier 31b and the delay circuit 32b. The data is input to the adder 33b. In this way, two received ultrasonic beams having different directions can be formed by giving different combinations of delay times to received signals from a large number of transducers 11 in the array and then adding them. Since reception ultrasonic beams in two directions are obtained by one reception, half the time is required to obtain the number of reception ultrasonic beams necessary for reconstructing an image, and the frame rate can be increased.
Japanese Patent Laid-Open No. 10-328185

  On the other hand, using the fact that the delay time of the received signal from each transducer of the ultrasonic transducer array is symmetric with respect to the center of the combined received ultrasonic beam, if the same delay time is given to the symmetrical transducer, For this reason, a technique of halving the reception channel that gives different delay amounts is also known. For example, as shown in FIG. 5 showing only the receiving circuit 13, for a pair of transducers 11 that only need to provide a symmetric (same) delay time, the outputs are combined and added, and then one amplifier 31 and one The signal is passed through a reception channel including the delay circuit 32. In this way, different delay times are given to the added reception signals of each pair, and the addition is performed by the adder 33. According to the technology using this symmetry, as can be seen from FIG. 5, the number of reception channels can be halved, which is advantageous in terms of cost. In addition, since reception signals from more transducers can be used with the same number of reception channels, reception ultrasound can be focused to a deeper position using reception signals from many transducers. This makes it possible to obtain an image with excellent image quality up to a deep location.

  However, although these parallel scanning techniques and techniques using symmetry are advantageous, as can be seen from FIGS. 4 and 5, they are not compatible in principle, and these advantages cannot be utilized simultaneously.

  In view of the above, an object of the present invention is to provide an improved ultrasonic diagnostic apparatus that can optimize a scanning method in accordance with the setting of ultrasonic conditions.

  In order to achieve the above object, in the ultrasonic diagnostic apparatus according to claim 1, a transducer array in which a large number of ultrasonic transducers are arranged, and each of these transducers is transmitted through an ultrasonic frequency through a delay unit. Transmitting means driven by a pulse of the above, signal switching means for switching received signals from each of the vibrators, amplifying means for amplifying each of the received signals that have passed through the signal switching means, and the amplification Receiving means including a delay means having the same number as the transducers and a signal adding means for adding the received signals passed through the delay means, and a delay means for each of the transmitting means and the receiving means. A first signal switching state in which the signal switching means of the receiving means is controlled and the received signals from the respective vibrators are switched to pass through one amplifying means and delay means respectively. And a control means for enabling selection of a second signal switching state in which received signals from each of the number of vibrators equal to or less than half are passed through two amplifying means and delay means, respectively. It has become.

  Further, in the ultrasonic diagnostic apparatus according to claim 2, a transducer array in which a large number of ultrasonic transducers are arranged, and transmission in which each of these transducers is driven by an ultrasonic frequency pulse that has passed through a delay means, respectively. Means, signal switching means for switching received signals from each of the vibrators, amplifying each of the received signals that have passed through the signal switching means, amplifying means for half of the vibrators, and received signals that have passed through the amplifying means. Receiving means including two delay means groups each of which is half the number of the transducers, and two signal adding means for adding the received signals that have passed through the two delay means groups for each set; In addition to controlling the delay means of each of the transmission means and the reception means, and controlling the signal switching means of the reception means, each of the reception signals from less than half of the vibrators is increased by one. The first signal switching state for switching to input to the means and the received signals from the two vibrators at positions symmetrical to the central axis of the received ultrasonic wave are combined and input to one amplifying means, respectively. It is characterized by comprising control means for enabling selection of the second signal switching state to be switched.

  2. The ultrasonic diagnostic apparatus according to claim 1, wherein the receiving means includes a signal switching means for switching a received signal from each of the vibrators, and amplifying each of the received signals that have passed through the signal switching means as many as the vibrators. Means, delay means having the same number as the transducers, and signal adding means for adding the received signals passed through the delay means. The signal switching means is controlled by the control means, and the first signal switching state and the second signal switching state can be selected.

  In the first signal switching state, switching is performed so that the received signals from the respective vibrators are respectively passed through one system of amplification means and delay means. In this case, the transducer and the system of the amplifying means and the delay means have a one-to-one correspondence, which is a normal scanning method. On the other hand, in the second signal switching state, switching is performed so that the received signals from each of the transducers of less than half the number are passed through the two systems of amplification means and delay means. As a result, a reception signal that has passed through two groups of delay means is obtained, and a combined signal obtained by adding the reception signals that have passed through each of these groups of delay means is obtained for each group. By controlling the delay time, a reception ultrasonic beam in two directions can be formed, and so-called parallel scanning becomes possible, so that the frame rate can be increased.

  Therefore, for example, when the focus is set to a deep position via the user interface, the control means sets the signal switching means to the first signal switching state and scans from all ultrasonic transducers by a normal scanning method. It is possible to effectively focus to a deep position using the received signal. In addition, when a focus is set at a shallow position via the user interface, the number of ultrasonic transducers used for both transmission and reception of ultrasonic waves is usually small. Therefore, when the number of ultrasonic transducers is small and the number of transducers less than half of the total number of elements is used for reception, the received signals from the respective transducers to be used are amplified by two systems respectively. By switching the signal switching means so as to pass through the delay means, parallel scanning can be performed and the frame rate of the ultrasonic image can be increased. Furthermore, when one ultrasonic image is picked up by transmission multi-focus, etc., when the shallow transmission focus area satisfies the above-mentioned conditions for parallel scanning, signals received from transducers that are less than half of the total number are received. A parallel scan is performed to improve the frame rate in that area, and in the deep transmission focus area, the reception signals from all ultrasonic transducers can be used to focus to a deep position. In this way, the present invention can also be applied to single ultrasonic imaging.

  In the ultrasonic diagnostic apparatus according to claim 2, the receiving unit includes a signal switching unit that switches a reception signal from each of the transducers, and a half of the transducers that amplify each of the reception signals that have passed through the signal switching unit. Amplifying means, two sets of delay means groups each of which is half the number of the above-mentioned transducers for delaying the received signals that have passed through the amplifying means, and two sets of received signals that have passed through the two sets of delay means groups for each set The signal adding means is included. Thus, since the amplification means may be half of the vibrator, the manufacturing cost can be reduced. The signal switching means is controlled by the control means, and the first signal switching state and the second signal switching state can be selected.

  In the first signal switching state, switching is performed so that received signals from half or less of all the vibrators are input to one amplifying means. In this case, the output of the amplifying means is Input to two sets of delay means. Therefore, both outputs of the two signal adding means for controlling the delay time of each of the delay means in both sets of these two sets of delay means and adding the received signals respectively passing through both sets of the delay means groups. If this is used, it is possible to form a reception ultrasonic beam in two directions, and so-called parallel scanning is possible, so that the frame rate can be increased.

  On the other hand, in the second signal switching state, the received signals from the two transducers that are symmetric with respect to the central axis of the received ultrasonic wave are combined and input to one amplifying unit, respectively. Can be switched. In this case, the output of the amplifying means is input to two groups of delay means, and the signal adding means for controlling the delay time of each of the delay means of one set and adding the received signals that have passed through the set of delay means. By using only the output of, it is possible to form a received ultrasonic beam using the symmetry of delay time, and focus the received ultrasonic wave to a deep position using received signals from a number of ultrasonic transducers. It can be effective.

  Therefore, for example, when the focus is set to a deep position via the user interface, the control means sets the signal switching means to the second signal switching state, and performs delay time control using symmetry, It is possible to effectively focus to a deep position using the received signal from the ultrasonic transducer. In addition, when a focus is set at a shallow position via the user interface, the number of ultrasonic transducers used for both transmission and reception of ultrasonic waves is usually small. Therefore, when the number of ultrasonic transducers is small and the number of transducers less than half of the total number of elements is used for reception, the control means uses the signal switching means as the first signal switching state. A reception signal from each transducer is input to one amplification unit. In this case, since the number of vibrators is less than half, the vibrator and the amplifying means are connected one-to-one, but the amplifying means and the delay means are connected one-to-two. A so-called parallel scan is performed using both of the two added signals of the received signals that have passed through both sets of delay means groups, and the frame rate of the ultrasonic image can be increased. Furthermore, when one ultrasonic image is picked up by transmission multi-focus, etc., when the shallow transmission focus area satisfies the above-mentioned conditions for parallel scanning, signals received from transducers that are less than half of the total number are received. One frame can be used to improve the frame rate in that area by performing parallel scan, and improve the focus to a deep position by performing reception ultrasonic synthesis using symmetry in the deep transmission focus area The present invention can also be applied to ultrasonic image capturing.

  Next, an ultrasonic diagnostic apparatus embodying the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the ultrasonic diagnostic apparatus according to the first embodiment of the present invention comprises an array in which a large number of ultrasonic transducers 11 are arranged, and this transducer array is housed in an ultrasonic probe. It is done. A transmission circuit 12 and a reception circuit 13 are connected to each of the ultrasonic transducers 11 in the array. The transmission circuit 12 is provided with a pulse generator 21 that generates a pulse having an ultrasonic frequency, and this pulse is sent to each of the drive channels including the delay circuit 22 and the drive circuit 23. A drive channel is provided for each transducer 11, and the pulse delayed by the delay circuit 22 is sent to the drive circuit 23, and each of the ultrasonic transducers 11 is pulse-driven by the drive circuit 23.

  The reception circuit 13 includes a multiplexer (signal switcher) 34, a large number of reception channels including an amplifier 31 and a delay circuit 32, and an adder 33. The reception signal output from the transducer 11 is switched by the multiplexer 34 and then added by the adder 33 through each of a number of reception channels including the amplifier 31 and the delay circuit 32. Here, the number of reception channels including the amplifier 31 and the delay circuit 32 is the same as the number of the ultrasonic transducers 11.

  The signal after the addition is sent to the signal processing circuit 14 and subjected to gain adjustment processing, quadrature detection processing, filter processing, log compression processing, dynamic range adjustment processing, enhancement processing, and the like, and then sent to the image processing circuit 15. For example, a B-mode image that is a tomographic image of a specific cross section of the patient's body is formed, and further sent to the image monitor device 17 via the display circuit 16, and the B-mode image or the like is displayed on the display screen of the image monitor device 17. Will be.

  A user interface 19 including an input device such as a keyboard is connected to the control circuit 18 so that ultrasonic scanning conditions and the like can be input. The control circuit 18 controls the delay times of the delay circuits 22 and 32 of the transmission circuit 12 and the reception circuit 13 according to the input conditions, and further controls the multiplexer 34 to switch the reception signal. Along with these, the signal processing circuit 14, the image processing circuit 15, the display circuit 16 and the like are controlled. The input conditions are an ultrasonic frequency, a focal length, a depth of field, and the like. The focal length and the visual field depth are determined according to the position / size of the region of interest within the subject. The ultrasonic frequency is set according to the desired azimuth / distance resolution by selecting a high frequency if high resolution is to be obtained and a low frequency if not so much.

  When the focal length is set shallow (short), the ultrasonic aperture length is usually shortened in order to keep the F value constant. That is, the control circuit 18 controls so that the number of ultrasonic transducers 11 to be used is reduced. In the case where the focal length is not reduced and is in a normal range, the control circuit 18 is controlled so that the total number of the ultrasonic transducers 11 is used. At this normal focal length, the multiplexer 34 is controlled so that the ultrasonic transducer 11 and the reception channel including the amplifier 31 and the delay circuit 32 are connected one-to-one. Therefore, in this case, a normal electronic scan is performed by the delay time control of each delay circuit 32.

  As described above, depending on the depth of focus, the ultrasonic transducer 11 may use only half or less of the total number, and half of the reception channels are not used. Therefore, when the number of transducers 11 to be used becomes half the number of reception channels in this way, the control circuit 18 responds to this by receiving two output signals for each transducer 11 to be used. The multiplexer 34 is controlled so as to be sent to the channel, and the adder 33 is controlled so as to obtain an addition output for each combination of delay times so that two signal receiving systems as shown in FIG. 4 are formed. That is, in this case, the adder 33 operates as two adders that respectively add the received signals that have passed through the two sets of delay circuit groups to obtain respective added outputs. As a result, it is possible to obtain the addition output added through the combination of the delay times on one side and the addition output added through the combination of the delay times on the other side. By appropriately determining the delay time group, so-called two-way simultaneous reception (parallel scan) can be performed.

  Further, when the number of ultrasonic transducers 11 to be used is ¼ or less of the total number, signal switching by the multiplexer 34 is performed so that the output signals of the transducers 11 to be used are sent to the four reception channels, respectively. In addition, the adder 33 can obtain an addition output for each group of the received signals that have passed through each of the four groups of delay circuits, thereby enabling simultaneous reception in four directions. Simultaneous reception in multiple directions is also possible.

  FIG. 2 is a block diagram showing an ultrasonic diagnostic apparatus according to the second embodiment of the present invention. Here, the receiving circuit 13 includes a multiplexer (signal switcher) 34, an amplifier group composed of half the amplifiers 31 of the ultrasonic transducer 11, and a first set of delay circuit groups composed of half delay circuits 32a. In addition to the first adder 33a, the second adder 33b includes a second set of delay circuits, each of which includes the half of the delay circuits 32b to which the output from the amplifier 31 is input. In addition, the configurations of the transmission circuit 12, the signal processing circuit 14, the image processing circuit 15, the display circuit 16, the image monitor device 17, the control circuit 18, the user interface 19, and the like are the same as those in FIG.

  In the configuration of FIG. 2, when only reception signals from half or less of the vibrators 11 are used, the control circuit is configured so that the reception signals from the half or less of the vibrators 11 are respectively input to one amplifier 31. 18, the multiplexer 34 is switched (first signal switching state). The output signal of each amplifier 31 is sent to a first set of delay circuits comprising a delay circuit 32a and a second set of delay circuits comprising a delay circuit 32b, and these first and second sets of delay circuits. The received signals that have passed through the above are added by each of the adders 33a and 33b for each set, and an addition output for each set is obtained.

  In this case, delay time control is performed for both of the delay circuits 32a and 32b belonging to the first and second sets of delay circuit groups, and a combined output of received signals delayed by a combination of different delay times is obtained, so-called Parallel scanning will be performed.

  Further, when the outputs of more than half of the total number of transducers 11 are used, the outputs of the two transducers 11 are combined and sent to one amplifier 31 under the control of the control circuit 18. The signal can be switched in the multiplexer 34 (second signal switching state).

  Therefore, when the focus is set to a shallow position via the user interface 19, the multiplexer 34 enters the first signal switching state, the parallel scan is performed, and the frame rate is improved.

  On the other hand, when the focal length is set deep (long), the multiplexer 34 enters the second signal switching state, and the ultrasonic transducer 11 positioned at a location symmetrical to the central axis of the received synthesized ultrasonic beam is set. The output signals of the pairs are added and each input to one amplifier 31. In this case, the output of each amplifier 31 is sent to a first set of delay circuits consisting of a delay circuit 32a and a second set of delay circuits consisting of a delay circuit 32b. The received signals that have passed through the respective circuit groups are added by each of the adders 33a and 33b for each set, and an added output for each set is obtained. One set (for example, the delay circuit 32a belongs). Only the delay time of the delay circuit group is controlled, and the signal is sent to the signal processing circuit 14 using only the output of the adder (for example, the adder 33a) that adds the received signals that have passed through the set of delay circuits. As a result, since a deep portion can be focused by delay time control using symmetry, the number of amplifiers 31 can be reduced to half of the total number of ultrasonic transducers 11, and the manufacturing cost can be reduced.

  In these first and second embodiments, when the user sets transmission multi-focus, the transmission synthesized ultrasonic wave has a wide focus area. Therefore, in this case, the control circuit 18 shown in FIGS. 1 and 2 can control the shallow focus area and the deep focus area so that different scanning methods are used. When the control circuit 18 determines that the shallow transmission focus area satisfies the above-described conditions for parallel scanning, the multiplexer 34 is switched to the second signal switching state in the configuration of FIG. 1, and the multiplexer 34 in the configuration of FIG. Are switched to the first signal switching state to perform parallel scanning. On the other hand, in the deep transmission focus region, the multiplexer 34 is in the first signal switching state in the configuration of FIG. 1 and normal electronic scanning is performed, and in the configuration of FIG. 2, the multiplexer 34 is in the second signal switching state. Since the delay time control using symmetry is performed and both the configurations of FIGS. 1 and 2 can be received using a large number of ultrasonic transducers 11, the focus can be improved to a deep position.

  The above description relates to one embodiment of the present invention, and it goes without saying that specific configurations and the like can be variously changed without departing from the spirit of the present invention.

  According to the ultrasonic diagnostic apparatus according to the present invention, the scanning method can be optimized according to the setting of the ultrasonic condition, the frame rate can be improved by parallel scanning according to the focus depth, or a small number of amplification means The focus can be improved to a deep position while reducing costs.

1 is a block diagram of an ultrasonic diagnostic apparatus according to a first embodiment of the present invention. The block diagram of the ultrasonic diagnosing device concerning 2nd Example of this invention. The block diagram of a prior art example. The block diagram of the receiving circuit which performs a parallel scan. The block diagram of the receiving circuit which performs the reception ultrasonic beam synthesis | combination using a symmetry.

Explanation of symbols

11 ………… Ultrasonic transducer 12 ………… Transmitting circuit 13 ………… Receiving circuit 14 ………… Signal processing circuit 15 ………… Image processing circuit 16 ………… Display circuit 17 ………… Image monitor device 18 Control circuit 19 User interface 21 Pulse generator 22, 32, 32a, 32b Delay circuit 23 Pulse drive circuit 31 Amplifiers 33, 33a, 33b... Adder 34.

Claims (2)

  A transducer array in which a large number of ultrasonic transducers are arranged, a transmission unit that drives each of these transducers with a pulse of an ultrasonic frequency that has passed through a delay unit, and a reception signal from each of the transducers described above Switching signal switching means, amplifying each of the received signals that have passed through the signal switching means, the same number of amplifying means as the vibrators, delaying the received signals that have passed through the amplifying means, respectively, and delaying means as many as the vibrators, and A receiving means including a signal adding means for adding the received signals that have passed through the delay means, and controlling the delay means of the transmitting means and the receiving means, and controlling the signal switching means of the receiving means, The received signal from each of the first signal switching state and the number of transducers less than half the number of the received signals is increased by two systems. Ultrasonic diagnostic apparatus characterized by comprising a control means for enabling selecting a second signal switching states for switching to pass the means and the delay means.   A transducer array in which a large number of ultrasonic transducers are arranged, a transmission unit that drives each of these transducers with a pulse of an ultrasonic frequency that has passed through a delay unit, and a reception signal from each of the transducers described above Signal switching means for switching, amplifying each of the reception signals that have passed through the signal switching means, amplifying means for half of the vibrator, and two sets of half of the vibrator for respectively delaying the reception signal that has passed through the amplification means The receiving means including two signal adding means for adding each of the delay means group and the received signals that have passed through the two sets of delay means groups for each set, and controlling the respective delay means of the transmitting means and the receiving means The first signal switching for switching so that the received signals from less than half of the vibrators are respectively input to one amplifying means by controlling the signal switching means of the receiving means. And a second signal switching state in which received signals from two transducers at symmetrical positions with respect to the central axis of the received ultrasonic wave are combined and switched so as to be input to one amplifying unit, respectively. And an ultrasonic diagnostic apparatus.

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