JP5209351B2 - Ultrasonic diagnostic apparatus and control method thereof - Google Patents

Description

  The present invention relates to an ultrasonic diagnostic apparatus and a control method thereof, and more particularly, an ultrasonic diagnostic apparatus that performs three-dimensional scanning with ultrasonic waves in a subject using a trigger signal generated from an electrocardiogram signal, and the like, and It relates to a control method.

  In recent years, development of an ultrasonic diagnostic apparatus capable of displaying a three-dimensional image as a moving image has been rapidly advanced, and a wide range of diagnostic images can be displayed with higher resolution than conventional two-dimensional images. It has become.

  However, since the ultrasonic diagnostic apparatus generates a diagnostic image using ultrasonic waves propagating in the living body, the time until the reflected wave from the living body is received after transmitting the ultrasonic pulse is three-dimensional ultrasonic waves. Even a diagnostic apparatus is basically the same as a two-dimensional ultrasonic diagnostic apparatus. Therefore, when scanning the three-dimensional spatial range in the living body with high resolution, the number of scanning beams increases, and the time required for scanning the predetermined range is longer than that of the two-dimensional ultrasonic diagnostic device. It is generally longer. That is, assuming the same spatial resolution, the frame rate of the 3D image obtained by the 3D ultrasound device (update frequency of the 3D image) is compared with the frame rate of the 2D image obtained by the 2D ultrasound diagnostic device. In principle, it becomes lower.

  In order to solve this problem, various methods have been studied conventionally (Patent Document 1, Patent Document 2, etc.). The basic idea is that the entire range to be diagnosed (hereinafter referred to as a full volume) is divided into a plurality of small areas (hereinafter referred to as subvolumes), and image data obtained by scanning the three-dimensional space of the subvolume at a high frame rate. Are combined to obtain a full volume three-dimensional image. In this method, since the observation time of the sub-volume is different for each sub-volume, it is important to ensure temporal continuity with respect to the joining of the sub-volumes.

  On the other hand, depending on the diagnostic site, the diagnostic site varies depending on breathing and heartbeat. For this reason, for example, Patent Literature 1 discloses a technique for acquiring a plurality of image data in a sub-volume in synchronization with the motion of the heart. The technique disclosed in Patent Document 1 and the like relates to a technique for generating a three-dimensional image of the heart in real time as a moving image, and is roughly the following technique.

  An electrocardiogram signal, that is, an ECG (ElectroCardioGram) signal is used as a signal synchronized with the motion of the heart. More specifically, an R wave signal generated at the end diastole of the heart is used as an ECG trigger signal.

  The entire three-dimensional region (full volume) of the heart to be observed is divided into four sub-volumes, and image data for one heartbeat is collected at a timing synchronized with the ECG trigger signal for each sub-volume. The image data for one heartbeat is composed of a plurality of frame images. For example, 20 frame images are collected per heartbeat. In this case, assuming that the cycle of the heartbeat is 1 second, the frame rate of the image data obtained for each subvolume is 20 fps (frames per second), which is a value that is almost sufficient to capture the motion of the heart as a moving image.

On the other hand, when combining full-volume image data by stitching together the image data obtained in each sub-volume, the same “time phase” frame image is selected from each of the plurality of frame images obtained in the sub-volume. Extract from volume and stitch together to create full volume frame image. Here, the “time phase” is a delay amount based on the generation time of the ECG trigger signal. Normally, the contraction and expansion movements of the heart are periodic movements in synchronization with the ECG trigger signal. Therefore, if the same “time phase” frame images are extracted from the respective sub-volumes and connected, the spatial continuity between the sub-volumes is almost ensured. Further, the frame images are joined to each of a plurality of (for example, 20) frame images having different “time phases”. As a result, the number of joined frame images is, for example, 20 per ECG trigger signal, and the frame rate of the full volume image is the same as the frame rate of the sub-volume. That is, for example, a full-volume moving image having a frame rate of 20 fps can be generated.
US Pat. No. 6,544,175 JP 2007-20908 A

  As described above, in the related art disclosed in Patent Document 1 and the like, one subvolume is repeatedly scanned a plurality of times for each ECG trigger signal, and one frame image (a subvolume frame image is obtained by one scan. ) Here, the number of repeated scans in the sub-volume is determined in advance from the ECG trigger signal before starting diagnosis with a three-dimensional image.

  However, the human heart cycle is not always constant, and it is said that even a healthy human will vary by about 10%. In the case of a patient having a disease such as arrhythmia, the amount of variation is further increased. Therefore, the cycle of the ECG trigger signal does not become constant as the heartbeat cycle varies.

  As a result, a situation may occur in which the number of repeated scans in the subvolume determined before the diagnosis is started cannot be ensured. In particular, when a state in which the cycle of the ECG trigger signal is shortened (this state is called an early trigger state) occurs, the next ECG trigger signal is output before the scan immediately before the ECG trigger signal is completed. The number of repeated scans cannot be ensured. This means that a frame image of the heart immediately before the ECG trigger signal is lost, and when a full-volume image is generated by joining the corresponding frame images of the same phase, one or a plurality of sub-volumes may be generated. This frame image becomes a missing tooth state, discontinuous in time and is difficult to see, and thus hinders image diagnosis.

  If the predetermined number of repeated scans has not been reached, the sub-volume scan may be repeated again after waiting for the ECG trigger signal period to change in a longer direction. However, if the early trigger state continues, the data of the corresponding subvolume cannot be collected any time, and the data collection time becomes unpredictable as a whole.

  In addition, a method of setting the margin period immediately before the ECG trigger signal in advance of the occurrence of an early trigger state, that is, a method of setting a small number of repeated scans within one heartbeat is conceivable. According to this method, although the instability of the generated image and the predictability of the acquisition time due to the periodic fluctuation of the ECG trigger signal are improved, the heart image immediately before the ECG trigger signal cannot always be obtained. It is not preferable.

  The present invention has been made in view of the above circumstances, and can stably acquire three-dimensional heart images in all states within one heartbeat without losing the heart image immediately before the ECG trigger signal. An object of the present invention is to provide an ultrasonic diagnostic apparatus that is capable of acquiring image data at a constant acquisition time and a control method thereof.

In order to solve the above-described problems, an ultrasonic diagnostic apparatus according to the present invention includes ultrasonic transducers arranged two-dimensionally, and scans an ultrasonic beam in the main scanning direction and the sub-scanning direction to reflect from within the subject. A scanning start trigger signal is generated from an ultrasonic probe that collects signals and a trigger signal that is output every heartbeat period, and a desired diagnostic region of the subject is divided into a predetermined number of divided regions. The scanning control unit that repeatedly scans the ultrasonic beam a plurality of times in synchronization with the scanning start trigger signal from the scanning start trigger signal to the next scanning start trigger signal, and the repeated scanning for each divided region an image generator for generating an image of the entire stitching the diagnosis region in association based on a portion of the data in the order of the repeating scanning to be, and wherein said scanning control unit, the Generates the scanning start trigger signal by decimating the trigger signal by a predetermined number, based on the period of the scan start trigger signal, determines the number N of repetitions scanning of the divided region, the period of the trigger signal Based on this, the number M of data to be stitched together to generate an image of the entire diagnosis area is determined, and the image generation unit is previously acquired from N data acquired by N repeated scans. The M data are extracted, and the extracted M data are connected to generate an image of the entire diagnostic region .

  According to the ultrasonic diagnostic apparatus and the control method thereof according to the present invention, three-dimensional heart images in all states within one heartbeat can be stably acquired without losing the heart image immediately before the ECG trigger signal. Image data can be collected at a constant collection time.

  Embodiments of an ultrasonic diagnostic apparatus and a control method thereof according to the present invention will be described with reference to the accompanying drawings.

(1) General and Configuration FIG. 1 is a diagram schematically illustrating a scanning state of an ultrasonic beam by the ultrasonic diagnostic apparatus 1 according to the present embodiment. In the ultrasonic diagnostic apparatus 1, a thin ultrasonic beam is formed by an ultrasonic probe 10 in which a plurality of ultrasonic transducers 11 are two-dimensionally arranged. This ultrasonic beam is emitted toward a desired diagnostic region of the subject, and the range of the diagnostic region is electronically scanned in the main scanning direction and the sub-scanning direction. Three-dimensional information in the main scanning direction, the sub-scanning direction, and the distance direction is obtained from the reflection signal of the diagnostic region.

  The scanning range of the conventional one-dimensional ultrasonic probe in which the ultrasonic transducers are arranged one-dimensionally is a planar range, whereas the scanning range of the two-dimensional ultrasonic probe 10 as in this embodiment is as follows. It becomes a three-dimensional solid range. In addition, since an ultrasonic beam having a narrow beam width is scanned, high-resolution three-dimensional information can be acquired from a wider diagnostic region. From the acquired three-dimensional information, a three-dimensional image viewed from an arbitrary direction or a cross-sectional image cut out at an arbitrary cross-section can be generated.

  On the other hand, since the ultrasonic beam is scanned in the main scanning direction and the sub-scanning direction, the number of beams for scanning the entire diagnostic region (full volume) is greatly increased with respect to the planar scanning range. As a result, if the range of the full volume is simply scanned sequentially from end to end, the time for scanning the full volume once increases. For this reason, the frame rate of a full volume image becomes low.

  Therefore, as described above, in the ultrasonic diagnostic apparatus 1 according to the present embodiment, the full volume is divided into a plurality of (for example, four) subvolumes, and each subvolume is scanned at a high frame rate (for example, 20 fps). In this method, the frame images obtained from the respective sub-volumes are combined and joined to synthesize a full-volume frame image. Since the frame rate of the full-volume image can be as high as the frame rate of the sub-volume (for example, 20 fps), it is possible to generate a three-dimensional moving image in real time even for a diagnostic region with motion such as the heart. It becomes possible.

  FIG. 2 is a block diagram illustrating a configuration example of the ultrasonic diagnostic apparatus 1. The ultrasonic diagnostic apparatus 1 includes, for example, an ultrasonic probe 10, a transmission / reception unit 20, a signal processing unit 30, an image generation unit 40, a display unit 50, a system control unit 60, a scanning control unit 70, an operation unit 80, and the like. Has been.

  The ultrasonic probe 10 includes a plurality of ultrasonic transducers 11 arranged in a lattice pattern, generates an ultrasonic pulse based on a transmission pulse signal output from the transmission unit 21 of the transmission / reception unit 20, Send to the specimen. In addition, the ultrasonic reflection signal reflected from the subject is converted into an electrical signal and output to the reception unit 22 of the transmission / reception unit 20. Further, the ultrasonic beam is scanned in the main scanning direction and the sub-scanning direction based on the beam scanning control signal output from the scanning control unit 70.

  The transmission unit 21 of the transmission / reception unit 20 generates a transmission pulse to be supplied to each ultrasonic transducer 11 based on the timing signal generated by the scanning control unit 70. Similarly, the delay amount of each transmission pulse is set in order to determine the scanning direction of the ultrasonic beam for transmission based on the beam scanning control signal generated by the scanning control unit 70.

  In the receiving unit 22 of the transmitting / receiving unit 20, the reflected signal from the subject output from each ultrasonic transducer 11 is amplified and converted from an analog signal to a digital signal. Further, based on the beam scanning control signal generated by the scanning control unit 70, a delay amount for determining the scanning direction of the ultrasonic beam for reception is set in the reflected signal of each ultrasonic transducer 11, and then added. The added signal is output to the signal processing unit 30 as a beam-formed reflection signal.

  In the signal processing unit 30, the reflected signal output from the receiving unit 22 is subjected to signal processing such as filtering processing, and is output to the image generation unit 40.

  The image generation unit 40 generates three-dimensional image data from the reflected signal in correspondence with the beam scanning position. In particular, in the ultrasonic diagnostic apparatus 1 according to the present embodiment, image data is generated for each sub-volume, and processing for synthesizing full-volume three-dimensional image data from each sub-volume image is performed. This combining process is a process linked to the operation of the scanning control unit 70, and details will be described later.

  The image generation unit 40 performs rendering processing on the synthesized full-volume three-dimensional image data, generates a three-dimensional image viewed from an arbitrary angle, a cross-sectional image cut at an arbitrary surface, and the like, and displays the display unit Output to 70. For example, the three-dimensional image data can provide a moving image that is updated every frame time of 20 fps. Although it is possible to output a moving image to the display unit 70 in real time during diagnosis, the image data is temporarily stored in an appropriate memory, and the moving image is output offline after diagnosis, or a part of the moving image is cut out to be a still image. Can also be output.

  The display unit 70 is a display device configured by, for example, a liquid crystal display device, and displays an image output from the image generation unit 40.

  The operation unit 80 is a so-called man-machine interface, and can set various diagnostic modes and various parameters associated with the diagnostic mode for the ultrasonic diagnostic apparatus 1. The ultrasonic diagnostic apparatus 1 according to the present embodiment is characterized by a diagnostic mode (hereinafter referred to as a triggered three-dimensional diagnostic mode) capable of displaying a heart motion beating based on an ECG trigger signal as a three-dimensional moving image. However, other conventional two-dimensional diagnostic modes can also be operated. Setting and switching of these diagnostic modes are performed via the operation unit 80.

  The system control unit 60 controls the entire ultrasound diagnostic apparatus 1 based on the diagnosis mode and various parameters set by the operation unit 80.

  The scanning control unit 70 performs beam management of ultrasonic beams and transmission / reception time management according to the diagnostic mode. In particular, in the triggered three-dimensional diagnostic mode, a trigger signal is generated from the ECG signal (R wave) output from the electrocardiograph 100, and the beam scanning position (main scanning direction and sub-scan) for each sub-volume is synchronized with this trigger signal. The scanning direction) and specifications regarding repeated scanning in the sub-volume are determined and output to the transmission / reception unit 20 and the image generation unit 40. Also, transmission pulse specifications such as a transmission pulse repetition frequency (prf) of the ultrasonic beam are determined, and various timing signals based on the transmission pulse specifications are also generated by the scanning control unit 70.

(2) Operation in Triggered Three-Dimensional Diagnosis Mode The operation of the ultrasonic diagnostic apparatus 1 configured as described above, particularly the operation in the triggered three-dimensional diagnostic mode will be described.

  FIG. 3 is a diagram for explaining the operation principle of the triggered three-dimensional diagnosis mode, which is a technique disclosed in Patent Document 1, for example. The triggered three-dimensional diagnosis mode is a diagnosis mode in which the heart is mainly targeted for diagnosis, and the heart motion that changes due to the heartbeat is displayed as a three-dimensional moving image. In the triggered three-dimensional diagnosis mode, an electrocardiogram signal (ECG signal) that changes according to the heartbeat of the patient is input from the electrocardiograph 100, and a pulse signal called an ECG trigger signal is generated. As the ECG signal, a pulsed R-wave signal (see FIG. 3A) output in the vicinity of the end diastole of the heart is often used. This ECG signal is input to the scanning control unit 70, and an appropriate threshold value is applied to generate an ECG trigger signal (see FIG. 3B). The ECG trigger signal is a signal synchronized with the heartbeat, and when the heartbeat is 60 times per second, the cycle of the ECG trigger signal is 1 second.

  In the triggered three-dimensional diagnosis mode, the entire diagnosis area (full volume) is divided into a plurality of subvolumes (divided areas), and each subvolume is scanned for each ECG trigger signal. For example, as illustrated in FIG. 3F, the full volume is divided into four sub-volumes A, B, C, and D. Then, the sub-volumes A, B, C, and D are scanned in order in accordance with the inputs of the triggers 0, 1, 2, and 3 of the ECG trigger signal.

  At this time, instead of scanning each subvolume only once, scanning is repeated a plurality of times (N times). FIG. 3 shows an example in which repeated scanning is performed four times (N = 4). Since one scanning time T for each sub-volume corresponds to the moving image frame time (reciprocal of the frame rate) as described later, in order to obtain a moving image with smooth motion, for example, 50 ms (= 1/20 fps) ) Before, after, or less is preferable. Assuming that the period of the ECG trigger signal is 1 second and that one scan time is 50 ms, the number of repeated scans N for each sub-volume is 20. FIG. 3 shows an example in which the number of repeated scans N for each subvolume is 4 for convenience of explanation.

  Even if the same sub-volume is scanned repeatedly, the heart is beating periodically, so that the delay time from the ECG trigger, that is, the image data generated from each repeated scan differs if the time phase is different. It will be.

  The time phase numbers shown in FIG. 3C are obtained by dividing the time phase in units of one scanning time, and are numbered as “0”, “1”, “2”, “3” from the closest to the ECG trigger signal. It is attached. In FIG. 3D, the time numbers “0”, “1”, “2”, and “3” and the sub-volumes A, B, C, and D are assigned “A0” to “A3”, “ The scanning order of the ultrasonic beams is arranged in time series in association with each other as “B0” to “B3”, “C0” to “C3”, and “D0” to “D3”.

  From the signal processing unit 30, the reflected signal from the subject subjected to the signal processing is output to the image generation unit 40 in real time according to the scanning order.

  FIG. 3E is a diagram illustrating a full volume composition method performed by the image generation unit 40. In the image generation unit 40, data of the same time phase number is extracted from the data of each subvolume identified by the time phase number, and the subvolumes A, B, C, and D are connected and combined. Even when the sub-volume data has the same time phase number, the time when they are actually acquired is different for each period of the ECG trigger signal. However, since the change in the shape of the heart is considered to have the same periodicity as that of the ECG trigger signal, the spatial continuity of the full volume image obtained by connecting the sub-volumes of the same time phase number is It will be almost secured.

  At the time when the data of the subvolume “D0” corresponding to the time phase number 0 is acquired, the data of the subvolumes “A0”, “B0”, and “C0” have already been acquired. A full volume image corresponding to 0 is generated.

  Next, at the time when the data of the subvolume “D1” corresponding to the time phase number 1 is acquired, the data of the subvolumes “A1”, “B1”, and “C1” have already been acquired, and the time phase number A full volume image corresponding to 1 is generated. In the same manner, full-volume images with time phase numbers 2 and 3 are formed.

  When the scanning “D3” of the sub-volume D is completed, the scanning returns to the sub-volume A and scanning is performed. At this time, the scan data “A0” obtained first is replaced with “A0” of the full volume data of time phase number 0 that was generated one time before, and a new full volume image of time phase number 0 is updated. Will be.

  Thus, a full volume image is generated or updated in units of one scanning time T for each subvolume.

  This means that even if the scanning time for the entire full volume is actually long, it can be seen as if the entire full volume has been scanned with the scanning time for one subvolume. That is, it means that the frame rate of the sub-volume image and the frame rate of the full-volume image can be made the same in a pseudo manner.

  For example, it is assumed that the frame rate of a full-volume image can be achieved only by 5 fps due to scanning time restrictions in the normal method. Even in this case, by dividing the full volume into four sub-volumes, the scanning time of each sub-volume becomes ¼ of the full volume, and the frame rate of the sub-volume image is 20 times as high as 20 fps. . In the triggered three-dimensional diagnosis mode, the frame rate of the sub-volume image becomes the frame rate of the full-volume image as it is, so that a frame rate that is four times higher than that of the normal method can be obtained.

  In this way, the triggered 3D diagnostic mode produces high-resolution images at a high frame rate even for a wide 3D diagnostic area, so it generates real-time videos even for diagnostic objects with motion such as the heart. Is possible.

  By the way, in general, a human heartbeat cycle is not necessarily constant. It is said that even a healthy person has a fluctuation in heart rate cycle of about 10%. In patients with heart disease, the fluctuations in the heart cycle are even greater. Due to this heartbeat cycle variation, the conventional triggered three-dimensional diagnosis mode has a problem that it is difficult to obtain image data for a certain period immediately before the ECG trigger signal.

  FIG. 4 is a diagram for explaining this problem. 4A shows an ECG trigger signal, FIG. 4B shows a scanning order of ultrasonic beams, and FIG. 4C shows a state in which a full volume image is generated from subvolume data. FIG. 4D is a diagram showing the relationship between the full volume and the sub-volume.

  Also in FIG. 4, the number of sub-volumes is 4 as in FIG. 3, and is indicated by sub-volumes A, B, C, and D, respectively. On the other hand, the number of repeated scans N for each sub-volume is different from that in FIG. 3, and 16 repeated scans are performed in FIG. The order of repeated scanning in the sub-volume is related to the time phase number as in FIG. 3, and the last two digits of the 3-digit number are the time phase numbers in FIG. For example, “A000” represents the scan data of time phase number 0 in the subvolume A, and “B001” represents the scan data of time phase number 1 in the subvolume B.

  FIG. 4B is a diagram specifically showing the problems of the conventional triggered three-dimensional diagnosis mode, in which scanning data immediately before the ECG trigger signal indicated by dark hatching (scanning data corresponding to time phase number 15) is shown. Indicates that it cannot be obtained. Even the scan data in the period immediately before the ECG trigger signal is one scan data in a series of heart movements. The inability to acquire scan data during this period is an obstacle to diagnosis. The reason why such an unacquired period occurs will be described below.

  In general, before starting diagnosis (image generation and display) in the triggered three-dimensional diagnosis mode, an ECG waveform signal is acquired in advance and the heartbeat period T is measured. Based on the measured heartbeat period T (ECG trigger signal period), the number N of repeated scans per sub-volume is determined. At this time, if the number of repeated scans N is too small, the period during which data cannot be acquired immediately before the ECG trigger signal increases, which is not preferable. Conversely, if the number of repeated scans N is too large, the entire period of repeated scans will exceed the heartbeat period T.

  Therefore, the number of repeated scans N is determined so that the maximum number of repeated scans can be secured within a range not exceeding the heartbeat period T. For example, as shown in FIG. 4, the number of repeated scans N is determined to be 16 so that the entire scanning period fits within the ECG trigger interval. However, since the heartbeat period T varies, it may occur that the next ECG trigger signal arrives before the determined number of repeated scans N is reached. In this case, the corresponding subvolume is repeatedly scanned again. Here, when the next ECG trigger signal arrives again before reaching the determined number N of repeated scans, the same subvolume is repeatedly scanned again. When the cycle of the ECG trigger signal varies, the determined number of repeated scans N is ensured, so that the next sub-volume scan can be performed, but this is a long time while the cycle of the ECG trigger signal is shortened. If it continues, there may occur a situation in which it is not possible to shift to the next sub-volume scan indefinitely. When such a situation occurs, not only does the data acquisition time extend, but there is a problem that the data acquisition period cannot be predicted.

  In order to avoid such a situation, it is unavoidable to provide a margin period in advance immediately before the ECG trigger signal and repeatedly determine the number of scans N on the assumption that this margin period exists. This margin period is a period corresponding to the time phase number 15 indicated by dark hatching in FIG.

  Since scanning data is not acquired during this margin period, as shown by dark hatching in FIG. 4C, when a full-volume image is generated as a moving image, a certain period immediately before trigger 4 or immediately before trigger 8 The image is not updated for a certain period of time. This is not simply a problem in image display, but because data for that period is not acquired in the first place, it can be a serious problem in image diagnosis. The above is the problem of the conventional triggered three-dimensional diagnosis mode.

  In order to solve the above problem, in the ultrasonic diagnostic apparatus 1 according to the present embodiment, a part of the ECG trigger signal is thinned out to newly generate a scan start trigger, and the scan of each sub-volume is scanned by this scan start trigger signal. The control method to start is adopted. Hereinafter, this control method will be described.

  FIG. 5 is a flowchart showing a processing example of the control method of the ultrasonic diagnostic apparatus 1 according to the present embodiment, and FIG. 6 is an operation explanatory diagram thereof. FIG. 6 is a diagram corresponding to FIG. 4 showing the conventional problems.

  First, in step ST1 (FIG. 5), an electrocardiogram waveform (R wave) is input to generate an ECG trigger signal. Next, every other ECG trigger signal is thinned out to generate a scan start trigger (step ST2). FIG. 6A shows an ECG trigger signal, and FIG. 6B shows a scan start trigger generated by thinning out every other ECG trigger signal.

  Next, the sub-volume A is repeatedly scanned using the scan start trigger as a start signal (step ST3). At this time, the number of repeated scans for each sub-volume is determined based on the scan start trigger cycle, not the ECG trigger signal cycle. When every other sampling is thinned out, the scanning start trigger cycle is twice as long as the ECG trigger cycle, so the number of repeated scans according to the present embodiment is approximately twice that of the conventional repeated scan number. In the conventional example of FIG. 4, the repeated scanning number N is set to 15 (14 in the time phase number excluding the margin period), whereas in the example of FIG. 6 according to the present embodiment, the repeated scanning number N is set. 31 (30 in the time phase number) is set. However, the scanning start trigger cycle also varies with the ECG trigger cycle variation. Therefore, also in this embodiment, a margin period (a dark hatching period in FIG. 6C) is provided in the period immediately before the scanning start trigger so as to absorb the fluctuation of the scanning start trigger.

  When the repetitive scanning of the sub-volume A reaches a predetermined number (31 in this case), the repetitive scanning of the sub-volume B is started using the next scanning start trigger as a start signal. In the same manner, a predetermined number of repeated scans are performed up to the sub-volume D. When scanning of all sub-volumes is completed (YES in step ST4), the process proceeds to step ST5, where the scan data of the sub-volumes having the same time phase number are connected to generate a full volume image.

  The processing in step ST5 is basically the same as the conventional method, but the maximum value of the time phase number is not the maximum value that can be taken within the scan start trigger period, but the maximum value that can be taken within the ECG trigger period. Value. That is, “A00” to “A015” are used for the synthesis of the full volume as the scan data of the sub-volume A, and the remaining scan data from “A016” to “A30” are discarded.

  According to this method, since it is not necessary to provide a margin period immediately before the trigger 1 in the repeated scanning with respect to the sub-volume A, scanning data is acquired without omission over the entire period of the heartbeat from time phase number 00 to time phase number 15. It becomes possible.

  Further, the period variation of the scan start trigger can be absorbed by the immediately preceding margin period. In FIG. 6C, a period corresponding to one scanning time is set as the margin period. However, in practice, a longer margin period than the period from the trigger 1 to the trigger 2 can be taken. For this reason, even if a considerably large period fluctuation occurs, the fluctuation can be absorbed in a long margin period. For this reason, the situation where scanning data acquisition is repeated many times due to periodic fluctuations does not occur, and stable data acquisition is always possible within a fixed time.

  Similar processing is performed on the sub-volumes B, C, and D, and the scan data having the same time phase number is connected to generate a full-volume image. As a result, as shown in FIG. 6D, it is possible to generate a continuous full volume image without missing in the time direction.

  The generated three-dimensional full volume image is rendered into a two-dimensional image viewed from a desired angle, or converted into a two-dimensional cross-sectional view cut out at a desired cross-section and output to the display unit 50.

  Although it takes time for eight ECG triggers to generate a full volume image for the first time (in the conventional method, it takes four ECG triggers to generate a full volume image for the first time). Once a full-volume image has been generated, the update period is the scanning time for one sub-volume. In the method according to the present embodiment, the number of repeated scans per subvolume is increased compared to the conventional method, but the scanning time per subvolume is not different from the conventional method. Therefore, a moving image having the same high frame rate as that of the conventional method can be generated.

  In the above description, the example in which the scanning start trigger signal is generated by thinning out every other ECG trigger signal has been described, but the number of thinning out may be two or more. Further, the thinning number may be set and changed from the operation unit 80 or the like.

  As described above, according to the ultrasonic diagnostic apparatus 1 and the control method thereof according to the present embodiment, all states within one heartbeat can be obtained without losing the heart image immediately before the ECG trigger signal. A three-dimensional heart image can be acquired stably, and image data can always be acquired with a fixed acquisition time.

  Note that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, the constituent elements over different embodiments may be appropriately combined.

The figure which shows typically the beam scanning of a three-dimensional ultrasonic diagnostic apparatus. 1 is a block diagram showing a configuration example of an ultrasonic diagnostic apparatus according to the present invention. General operation concept explanatory drawing of triggered 3D diagnostic mode. The figure explaining the problem of the conventional triggered 3D diagnostic mode. The flowchart which shows the operation processing example of the triggered 3D diagnostic mode in the ultrasonic diagnosing device which concerns on this invention. Operation | movement explanatory drawing of triggered 3D diagnostic mode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ultrasonic diagnostic apparatus 10 Ultrasonic probe 11 Ultrasonic transducer 20 Transmission / reception part 30 Signal processing part 40 Image generation part 50 Display part 60 System control part 70 Scan control part 80 Operation part

Claims (8)

An ultrasonic probe in which an ultrasonic transducer is two-dimensionally arranged and scans an ultrasonic beam in a main scanning direction and a sub-scanning direction to collect a reflection signal from the inside of the subject;
A scan start trigger signal is generated from a trigger signal output for each heartbeat cycle, and the next diagnosis region of the subject is divided into a predetermined number, and each of the divided regions is divided into the following from the scan start trigger signal. A scanning control unit that repeatedly scans the ultrasonic beam a plurality of times in synchronization with the scanning start trigger until a scanning start trigger signal;
An image generation unit that generates an image of the entire diagnosis region by associating and joining a part of data acquired by repeated scanning for each divided region based on the order of the repeated scanning;
With
The scanning control unit
Generating the scan start trigger signal by thinning out the trigger signal by a predetermined number ;
Based on the period of the scan start trigger signal, determine the number N of repeated scans in the divided area,
Based on the period of the trigger signal, the number M of data to be joined to generate an image of the entire diagnostic region is determined,
The image generation unit
Extracting the M data acquired previously from N data acquired by the N repeated scans, and connecting the extracted M data to generate an image of the entire diagnostic region;
An ultrasonic diagnostic apparatus. The scanning control unit generates the scanning start trigger signal by thinning out every other trigger signal.
The ultrasonic diagnostic apparatus according to claim 1. The scanning control unit is configured to be able to change the thinning number of the trigger signal by setting from the outside.
The ultrasonic diagnostic apparatus according to claim 1. (A) Scanning the ultrasonic beam in the main scanning direction and the sub-scanning direction to collect reflection signals from within the subject,
(B) generating a scanning start trigger signal from a trigger signal output for each heartbeat cycle;
(C) For each of the divided regions obtained by dividing the desired diagnostic region of the subject into a predetermined number, the scan start trigger signal is synchronized with the scan start trigger during the period from the scan start trigger signal to the next scan start trigger signal. The ultrasonic beam is scanned repeatedly several times,
(D) A part of data acquired by repeated scanning for each of the divided regions is associated and linked based on the order of the repeated scanning to generate an image of the entire diagnostic region.
With steps,
In step (b)
Generating the scan start trigger signal by thinning out the trigger signal by a predetermined number ;
Based on the period of the scan start trigger signal, determine the number N of repeated scans in the divided area,
Based on the period of the trigger signal, the number M of data to be joined to generate an image of the entire diagnostic region is determined,
In step (d),
Extracting the M data acquired previously from N data acquired by the N repeated scans, and connecting the extracted M data to generate an image of the entire diagnostic region;
A method for controlling an ultrasonic diagnostic apparatus. In step (b), every other trigger signal is thinned to generate the scan start trigger signal.
The method of controlling an ultrasonic diagnostic apparatus according to claim 4. In step (b), the number of thinned out trigger signals can be changed by setting from the outside.
The method of controlling an ultrasonic diagnostic apparatus according to claim 4. A margin period is provided before the scan start trigger,
The ultrasonic diagnostic apparatus according to claim 1. A margin period is provided before the scan start trigger,
The method of controlling an ultrasonic diagnostic apparatus according to claim 4.

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