JP2011045472A - Ultrasonic diagnostic apparatus and method of controlling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic diagnostic apparatus, more equally disposing ultrasonic beams in a three-dimensional space to generate a three-dimensional image of a heart in a shorter time. <P>SOLUTION: This ultrasonic diagnostic apparatus includes: an ultrasonic probe in which a one-dimensional array is rotatably constructed to an axis passing the center of the one-dimensional array and orthogonal to the array surface of ultrasonic vibrators; a beam scanning part for scanning the ultrasonic beams in two dimensions during the rotation of the one-dimensional array; and an image generating part, which generates two-dimensional beam data and synthesizes a plurality of two-dimensional beam data obtained by rotating the one-dimensional array to further generate a three-dimensional image. The beam scanning part scans the ultrasonic beams so that a difference between the array density of ultrasonic beams in a space near the axis of rotation of the one-dimensional array and the array density of the ultrasonic beams in a space radially distant from the space near the axis of rotation is made smaller in a three-dimensional space obtained by the rotation of the one-dimensional array and two-dimensional scanning. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an ultrasonic diagnostic apparatus and a control method thereof, and more particularly to an ultrasonic diagnostic apparatus capable of acquiring three-dimensional data and a control method thereof.

  One of the ultrasonic probes used in an ultrasonic diagnostic apparatus capable of acquiring three-dimensional data is a multi-plane TEE (TransEsophageal Echocardiography) ultrasonic probe (hereinafter simply referred to as a TEE probe). Reference 1).

  The TEE probe is an ultrasound probe that is orally inserted into the upper digestive tract such as the esophagus and stomach, and images the heart and the like with ultrasound. Ultrasonic transducers are arranged as a one-dimensional array at the tip of the TEE probe, and a sector-like tomographic image (two-dimensional image) can be taken with respect to the heart or the like by sector scanning of the ultrasonic beam. .

  In the TEE probe, the one-dimensional array can be rotated by a motor or the like with respect to an axis that passes through the center of the one-dimensional array and is orthogonal to the ultrasonic transducer surface. A tomographic image can be taken. By synthesizing a plurality of tomographic images obtained while rotating the one-dimensional array, for example, 180 degrees, a three-dimensional image of the heart or the like can be obtained.

JP 2007-159930 A

  In a conventional ultrasonic diagnostic apparatus using a TEE probe, when performing sector scanning of an ultrasonic beam, scanning is performed so that the intervals of the ultrasonic beams are equal to each other. The ultrasonic beam is scanned with a uniform density.

  However, when an attempt is made to rotate a one-dimensional array and combine a plurality of tomographic images to obtain a three-dimensional image, the density (distribution) of the ultrasonic beam in the three-dimensional space is not uniform. Looking at the arrangement of the ultrasonic beams in the three-dimensional space in the circumferential direction of rotation, the ultrasonic beams are arranged at a close interval in a region near the rotation center, and are arranged at a coarse interval in a region away from the rotation center. become. That is, in the three-dimensional image obtained by the conventional ultrasonic diagnostic apparatus using the TEE probe, the arrangement interval of the ultrasonic beams is not uniform between the region near the rotation center of the one-dimensional array and the region away from the rotation center. As a result, a three-dimensional image with greatly different resolutions is obtained.

  On the other hand, the heart repeats expansion and contraction every cardiac cycle. When a one-dimensional array of TEE probes is rotated 180 degrees to synthesize a three-dimensional image, the heart is rotated while the one-dimensional array is rotated 180 degrees. Repeats dilatation and contraction several times, and the shape of the heart fluctuates periodically in synchronization with the cardiac cycle. For this reason, when synthesizing a three-dimensional image from a two-dimensional image, it is necessary to extract and synthesize a two-dimensional image having the same expanded state (or contracted state), that is, the same time phase (cardiac time phase) with respect to the cardiac cycle. There is.

  As a method for extracting a two-dimensional image of the same cardiac phase, there is a conventional method using an ECG trigger signal obtained from a subject's electrocardiogram waveform (also referred to as an ECG (Electrocardiogram) waveform). The heart cycle varies to some extent even in a healthy person, and the cycle of the ECG trigger signal is not constant. Therefore, in the conventional ultrasonic diagnostic apparatus using the TEE probe, when one ECG trigger signal is input, the one-dimensional array is rotated by a predetermined angle (for example, 10 degrees), and then the rotation is temporarily stopped. When another ECG trigger signal is input, a method of rotating the same angle and then stopping the rotation is used. According to this method, two-dimensional images having the same cardiac time phase are spatially equidistant images.

  However, this method repeats the rotation and stop of the one-dimensional array, which increases the time required to obtain a three-dimensional image.

  The present invention has been made in view of the above circumstances, and in an ultrasonic diagnostic apparatus that generates a three-dimensional image while rotating a one-dimensional array, the arrangement of ultrasonic beams in a three-dimensional space is made more uniform. It is another object of the present invention to provide an ultrasonic diagnostic apparatus capable of generating a three-dimensional image of a beating heart in a shorter time and a control method thereof.

In order to solve the above problems, an ultrasonic diagnostic apparatus according to the present invention includes a one-dimensional array in which ultrasonic transducers are arranged one-dimensionally, and the arrangement of the ultrasonic transducers passes through the center of the one-dimensional array. An ultrasonic probe configured such that the one-dimensional array is rotatable with respect to an axis orthogonal to a plane;
A two-dimensional beam data is generated from a beam scanning unit that two-dimensionally scans the ultrasonic beam formed by the one-dimensional array while the one-dimensional array is rotating, and an echo signal obtained by the two-dimensional scanning, An image generation unit that further generates a three-dimensional image by combining a plurality of the two-dimensional beam data obtained by rotating the two-dimensional array, and the beam scanning unit rotates the one-dimensional array and performs the two-dimensional scanning. In the three-dimensional space obtained by the above, the arrangement density of the ultrasonic beams in the space near the rotation axis of the one-dimensional array and the arrangement density of the ultrasonic beams in a space farther in the radial direction than the space near the rotation axis The ultrasonic beam is scanned so as to reduce the difference.

  Also, the control method of the ultrasonic diagnostic apparatus according to the present invention uses an ultrasonic probe including a one-dimensional array in which ultrasonic transducers are arranged one-dimensionally, and passes through the center of the one-dimensional array. The one-dimensional array is rotated with respect to an axis orthogonal to the array plane of the transducers, and the ultrasonic beam formed by the one-dimensional array is scanned two-dimensionally during the rotation of the one-dimensional array, and the two-dimensional scanning is performed. Generating the two-dimensional beam data from the echo signal obtained by the step (1), combining the plurality of the two-dimensional beam data obtained by the rotation of the one-dimensional array, and further generating a three-dimensional image. In the three-dimensional space obtained by the rotation of the one-dimensional array and the two-dimensional scanning, the ultrasonic beam in the space near the rotation axis of the one-dimensional array And column density, said that the difference between the arrangement density of the ultrasonic beams in the space farther radially than the spatial axis of rotation near the smaller, the scanning an ultrasonic beam, characterized in that.

  According to the ultrasonic diagnostic apparatus and the control method thereof according to the present invention, in the ultrasonic diagnostic apparatus that generates a three-dimensional image while rotating the one-dimensional array, the arrangement of the ultrasonic beams in the three-dimensional space is made more uniform. And a three-dimensional image of the beating heart can be generated in a shorter time.

The block diagram which shows the structural example of an ultrasound diagnosing device. The figure which shows the structural example of an ultrasonic probe (TEE probe) front-end | tip part. The figure which shows an example of the two-dimensional scan (sector scan) of the ultrasonic probe performed conventionally. Explanatory drawing which shows typically the relationship between the two-dimensional beam data obtained while rotating a one-dimensional array 180 degree | times, and a cardiac time phase. The figure explaining the method to synthesize | combine the three-dimensional image of the same cardiac time phase using STIC method. (A) is a figure which shows the conventional beam scanning example as a comparative example, (b) is a figure which shows the beam scanning example (1st Example) which concerns on this embodiment stomach. (A) is a figure which shows the conventional beam scanning example as a comparative example, (b) is a figure which shows the beam scanning example (2nd Example) which concerns on this embodiment stomach. The figure explaining the method to synthesize | combine the three-dimensional image of the same cardiac time phase using ECG method. The figure which shows the processing example of ECG method in case a cardiac cycle is not constant.

  Embodiments of the present invention will be described with reference to the accompanying drawings.

(1) Configuration and Basic Operation of Ultrasonic Diagnostic Device FIG. 1 is a block diagram illustrating a configuration example of the ultrasonic diagnostic device 1. The ultrasonic diagnostic apparatus 1 includes an ultrasonic probe 10, a transmission / reception unit 20, a signal processing unit 30, an image generation unit 40, a beam scanning unit 50, an ECG detection unit 60, an operation unit 70, a system control unit 80, a display control unit 90, and the like. It is configured with.

  The ultrasonic probe 10 generates an ultrasonic pulse based on the transmission pulse signal output from the transmission unit 21 of the transmission / reception unit 20 and transmits the ultrasonic pulse toward the subject. 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 probe 10 performs two-dimensional scanning of the ultrasonic beam based on the beam scanning control signal output from the beam scanning unit 50.

  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 beam scanning unit 50. 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 beam scanning unit 50.

  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 beam scanning unit 50, 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 includes a two-dimensional data generation unit 41, an image extraction unit 42, a three-dimensional image generation unit 43, a cardiac cycle estimation unit 44, and the like as its internal configuration. Although the specific operation of each part will be described later, the following general processing is performed.

  The two-dimensional data generation unit 41 generates two-dimensional beam data corresponding to the two-dimensional scanning with the ultrasonic probe 10, and sequentially stores them in the internal storage unit 41a. Based on the information on the estimated cardiac cycle output from the cardiac cycle estimation unit 44 and the ECG trigger signal output from the ECG detection unit 60, the image extraction unit 42 converts the two-dimensional beam data of the same cardiac phase into two-dimensional data. Extracted from the storage unit 41 a of the generation unit 41 and outputs a plurality of two-dimensional beam data of the same cardiac time phase to the three-dimensional image generation unit 43.

  The three-dimensional image generation unit 43 arranges the two-dimensional beam data in the three-dimensional coordinate space based on the rotation angle information of the one-dimensional array 12 when each two-dimensional beam data is obtained, and generates the three-dimensional beam data. To do. Further, the three-dimensional image generation unit 43 performs rendering processing on the generated three-dimensional beam data, and performs a three-dimensional image viewed from an arbitrary angle, a single cross-sectional image cut at an arbitrary surface, or MPR ( Multi-plane Reconstructed Image) is generated and output to the display unit 201 via the display control unit 90. Similarly, three-dimensional beam data is generated for each cardiac phase, and a three-dimensional image of each cardiac phase can be generated.

  The display control unit 90 can output these images to the display unit 201 in real time as a moving image during diagnosis. However, the display control unit 90 temporarily stores the image data in an appropriate memory and outputs the moving image offline after diagnosis. It is also possible to cut out a part of the moving image and output a still image. Furthermore, desired image condition data, patient information, an electrocardiogram waveform, and the like can be added to the display image and displayed on the display unit 201.

  The display unit 201 is a display device configured by, for example, a liquid crystal display device, and displays an image output from the display control unit 90.

  The ECG detection unit 60 generates an ECG trigger signal from the ECG signal (R wave) output from the electrocardiograph 200 and outputs the ECG trigger signal to the image extraction unit 42.

  The operation unit 70 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 system control unit 80 performs overall control of the ultrasonic diagnostic apparatus 1 based on the diagnosis mode and various parameters set by the operation unit 80.

  Several kinds of ultrasonic probes can be attached to the apparatus, and one of them is an ultrasonic probe 10 called a TEE probe. The ultrasound probe 10 can be inserted orally into the upper digestive tract such as the esophagus and stomach, and the heart and the like can be imaged with ultrasound.

  2A and 2B are diagrams schematically showing the configuration of the distal end portion of the ultrasonic probe 10. A one-dimensional array 12 in which a plurality of ultrasonic transducers 11 are arranged one-dimensionally is provided at the tip of the ultrasonic probe 10. The one-dimensional array 12 is configured to be rotatable about a rotation axis S that passes through the center of the array and is orthogonal to the arrangement surface of the ultrasonic transducers 11. For example, it can be rotated by a motor (not shown) in the direction of arrow A as shown in FIG. The rotation angle information of the one-dimensional array 12 is output from the ultrasonic probe 10 to the image forming unit 40.

  3A and 3B are diagrams illustrating an example of two-dimensional scanning (sector scanning) of the ultrasonic probe 10 conventionally performed. As shown in FIG. 3A, the ultrasonic beam is scanned in a line along the arrangement direction of the one-dimensional array 12.

  FIG. 3B is a diagram schematically showing the positional relationship between a heart as a subject and an ultrasonic beam scanned with respect to the heart. Two-dimensional beam data of one cut surface of the heart can be obtained by sector scanning of the ultrasonic probe 10. On the other hand, as described above, since the one-dimensional array 12 rotates about the rotation axis S, the cut surface of the heart also rotates. When the one-dimensional array 12 is rotated 180 degrees, a plurality of two-dimensional beam data covering the entire subject is obtained. By synthesizing the plurality of two-dimensional beam data based on the rotation angle information when the respective two-dimensional beam data is obtained, a three-dimensional image of the subject can be generated.

(2) Generation of heart image The heart repeatedly expands and contracts every cardiac cycle, and its shape is constant even while trying to synthesize a three-dimensional image by rotating a one-dimensional array of ultrasonic probes 10 by 180 degrees. There is no change. For this reason, if two-dimensional beam data in the same expanded state (or contracted state) are not synthesized, an image that is spatially distorted is obtained. The expanded state (or contracted state) within the cardiac cycle is called the cardiac phase, and when combining 3D images from 2D beam data, it is necessary to combine and combine 2D beam data of the same cardiac phase There is.

  FIG. 4 is an explanatory view schematically showing the relationship between the two-dimensional beam data obtained while rotating the one-dimensional array 12 180 degrees and the cardiac time phase. The illustrative example shown in FIG. 4 shows four times during which the one-dimensional array 12 rotates 180 degrees from angle A to angle B, from angle B to angle C, from angle C to angle D, and from angle D to angle A. It is shown that the expansion and contraction states in each cardiac cycle are obtained as two-dimensional beam data of eight states from the cardiac phase 1 to the cardiac phase 8.

  In the example of FIG. 4, the number of the two-dimensional beam data (the cut surface of the heart) of the same cardiac time phase is obtained only for the whole heart, and when a three-dimensional image is synthesized, a coarse image is obtained. FIG. 4 is illustrated from the viewpoint of explanation such as ease of viewing of the figure, and more two-dimensional beam data is actually synthesized. Also, the number of cardiac phases is not limited to eight as in the present example of description, and in fact, more cardiac phases can be taken.

  Hereinafter, a method for synthesizing a three-dimensional image having the same cardiac phase will be described in detail based on the example shown in FIG. There are two methods for synthesizing three-dimensional images of the same cardiac time phase: a method that does not use an electrocardiogram waveform (ECG signal) called a STIC (Spatiotemporal Image Correlation) method, Called). Any method can be used in the ultrasonic diagnostic apparatus 1 according to the present embodiment.

(3) STIC Method The STIC method is a method developed mainly for 4D imaging (three dimensions of space and one dimension of time) of the fetal heart. Since an electrocardiogram waveform cannot be obtained from the fetus, a method capable of generating a 4D image without using the electrocardiogram waveform has been developed, and this is the STIC method.

  FIG. 5 is a diagram for explaining a method of synthesizing a three-dimensional image having the same cardiac phase using the STIC method. FIG. 5A shows the two-dimensional beam data (frame data) generated by the two-dimensional data generation unit 41 and stored in the storage unit 41a in time series. Each of “*” shown in FIG. 5A represents two-dimensional beam data (frame data) obtained by one sector scan (the same applies hereinafter).

  In the STIC method, attention is paid to a change in luminance of a region of interest in two-dimensional beam data input continuously in time. The luminance signal is subjected to frequency analysis such as FFT and autocorrelation function calculation to obtain a fluctuation cycle, and the fluctuation cycle is estimated to be the average cardiac cycle T.

  Thereafter, as shown in FIG. 5B, the continuous two-dimensional beam data is divided by the estimated average cardiac cycle T. Then, for the two-dimensional beam data included in each of the divided areas, the cardiac phase numbers are assigned in order from the top, such as cardiac phase 1 and cardiac phase 2.

  The example shown in FIG. 5 (c) corresponds to FIG. 4, and in this example, the cardiac phase 1 to the cardiac phase 8 correspond to the two-dimensional beam data of the respective areas divided by the period T. Assigned. Further, the array rotation angle information such as “angle A” and “angle B” attached to FIG. 5C corresponds to the example of FIG.

  The image extraction unit 42 extracts two-dimensional beam data of the same cardiac time phase and generates a three-dimensional image by spatially synthesizing these data based on the array rotation angle information. This three-dimensional image corresponds to the number of cardiac time phases. In the example shown in FIGS. 4 and 5, eight three-dimensional images corresponding to eight cardiac time phases are generated.

  Further, by continuously outputting these three-dimensional images to the display unit 201 at the time interval t of the cardiac phase, it is possible to display a moving image of the heart updated at the frame rate t.

(4) Beam scanning method By the way, in the conventional ultrasonic diagnostic apparatus using the TEE probe, as shown in FIG. 3 and FIG. Are scanned at equal angles, and the ultrasonic beam is scanned at a uniform density in the scanning direction as far as one tomographic image is concerned.

  However, when the one-dimensional array 12 is rotated and the beam data of a plurality of tomographic planes are combined to obtain a three-dimensional image, the density (distribution) of the ultrasonic beam in the three-dimensional space is not uniform. Absent. When the arrangement state of the ultrasonic beam is viewed in a three-dimensional space, the conventional scanning method is arranged radially about the rotation axis S as shown in FIG. In the space in the vicinity of the rotation axis S, the ultrasonic beams are arranged at a dense interval (the interval between adjacent ultrasonic beams in the circumferential direction is narrow), whereas in an area away from the rotation axis S in the radial direction, the ultrasonic beam is coarse (circumferential direction). (The interval between the ultrasonic beams adjacent to each other is wide). That is, in the three-dimensional image obtained by the conventional ultrasonic diagnostic apparatus using the TEE probe, the arrangement interval of the ultrasonic beams is not uniform between the region near the rotation center of the one-dimensional array and the region away from the rotation center. As a result, a three-dimensional image with greatly different resolutions is obtained.

  Therefore, in the ultrasonic diagnostic apparatus 1 according to the present embodiment, the arrangement density of the ultrasonic beams in the space near the rotation axis S of the one-dimensional array 12 and the ultrasonic beam in a space farther in the radial direction than the space near the rotation axis S. The ultrasonic beam is two-dimensionally scanned so that the difference from the arrangement density of the two becomes small.

  FIG. 6B is a diagram showing a first embodiment of beam scanning, in which an ultrasonic beam is scanned with a non-uniform interval between the ultrasonic beams on the scanning surface of the sector scanning while the sector scanning is performed. Yes. More specifically, the ultrasonic beam is scanned in a region far from the center of sector scanning at a finer interval than the region near the center.

  As a result, the non-uniformity in the arrangement interval of the ultrasonic beams in the region in the vicinity of the rotation axis S of the one-dimensional array 12 and the region away from the region in the radial direction is reduced compared to the conventional case, and the difference in resolution is also increased. Will be reduced.

  FIG. 7B is a diagram showing a second embodiment of beam scanning (FIG. 7A is a diagram showing a conventional example for comparison).

  In the beam scanning according to the second embodiment, two-dimensional scanning is performed a plurality of times so as to share the range of one sector scanning that has been conventionally performed by a plurality of partial sector scans, thereby cutting the three-dimensional space radially. The number of dimension scan planes is increased. In the specific example shown in FIG. 7 (b), one sector scan P (see FIG. 7 (a)) that has been conventionally performed is divided into three partial sector scans P1, P2, and P3, and one conventional sector scan is performed. The space scanned by scanning is scanned by three two-dimensional scans. As a result, the number of two-dimensional scanning planes that radially cut the three-dimensional space is increased, and in the circumferential space where the conventional ultrasonic beam could not be scanned in a region away from the rotation axis S in the radial direction. In contrast, the ultrasonic beam can be arranged, and the uniformity of the arrangement interval of the ultrasonic beam is further improved as compared with the first embodiment.

  In the partial sector scans P2 and P3, an ultrasonic beam is arranged in a region radially away from the rotation axis S, and in the partial sector scan P1, the ultrasonic beam is emitted from the vicinity of the rotation axis S to the middle in the radial direction. It is arranged. In this way, in the plurality of partial sector scans P1, P2, and P3 that share one sector scan P and perform two-dimensional scan, the ultrasonic beams are arranged so as to be uniformly distributed in the radial direction of the three-dimensional space as a whole. This also improves the uniformity of the arrangement interval of the ultrasonic beams.

  In the beam scanning according to the second embodiment, the number of ultrasonic beams included in one conventional sector scan P and the total number of ultrasonic beams included in a plurality of partial sector scans to be shared are as follows. Scanning to be equal. In the example of FIG. 7B, the number of beams scanned by the partial sector scans P2 and P3 is 4, the number of beams scanned by the partial sector scan P1 is 8, and the total number of beams is 16. This is the same as the number of beams 16 included in one conventional sector scan P. This is because the beam scanning according to the second embodiment does not change the scanning range of the entire subject including the depth of the subject and the entire scanning time, that is, the basic necessary for diagnosis. This means that it is possible to increase the number of two-dimensional scanning planes that radiately cut a three-dimensional space without changing the various specifications, and as a result, the spatial uniformity can be improved. ing.

(5) ECG Method FIG. 8 is a diagram illustrating a method for synthesizing a three-dimensional image of the same cardiac phase using the ECG method. FIG. 8A illustrates an electrocardiographic waveform (ECG signal) input from an external electrocardiograph 200. FIG.

  The electrocardiogram waveform is input to the ECG detection unit 60 of the ultrasound diagnostic apparatus 1, and an ECG trigger signal (FIG. 8B) synchronized with the R wave of the electrocardiogram waveform is generated. The period of the ECG trigger signal corresponds in real time to the cardiac cycle of the heart under examination.

  On the other hand, the one-dimensional array 12 is continuously rotated while performing sector scanning, and two-dimensional beam data (frame data) (see FIG. 8B) is stored in the storage unit 41a of the two-dimensional data generation unit 41. It is memorized continuously. Each two-dimensional beam data can be associated with the rotation angle of the one-dimensional array 12 when it is acquired. For example, each two-dimensional beam data and rotation angle information are stored in the storage unit 41a in association with each other. You may let them.

  Each two-dimensional beam data can be associated with the time when it is acquired, and similarly, each two-dimensional beam data and the acquisition time may be stored in association with each other in the storage unit 41a. Alternatively, each beam data may be stored in association with position information in the three-dimensional space and acquisition time / acquisition time phase.

  The image extraction unit 42 divides continuous two-dimensional beam data (frame data) based on the ECG trigger signal (see FIG. 8D). Further, the cardiac phase number is assigned sequentially from the frame image immediately after the ECG trigger signal, and the number is assigned again from the cardiac phase 1 when the next ECG trigger signal appears.

  Subsequent processing is the same as in the STIC method, and two-dimensional beam data having the same cardiac time phase is extracted and spatially synthesized based on the array rotation angle information to generate a three-dimensional image. Similarly to the STIC method, it is possible to display a moving image of the heart updated at the frame rate t by continuously outputting these three-dimensional images to the display unit 201 at the time interval t of the cardiac phase. It is.

  Further, in this ECG method, the beam scanning method according to the first embodiment shown in FIG. 6B and the beam scanning method according to the second embodiment shown in FIG. The ultrasonic beam is reduced so that the difference between the arrangement density of the ultrasonic beams in the space near the rotation axis S of the two-dimensional array 12 and the arrangement density of the ultrasonic beams in the space farther in the radial direction than the space near the rotation axis S is small. Two-dimensional scanning is performed.

  By the way, in the ECG method, two-dimensional beam data having the same time phase is extracted based on the ECG trigger signal, but the cardiac cycle varies to some extent even in a healthy person, and the cycle of the ECG trigger signal is not constant. FIG. 9 is a diagram illustrating a processing example of the ECG method when the cardiac cycle is not constant.

  In the example shown in FIG. 9, the leftmost cardiac cycle is the longest, and eleven frame images (cardiac cycle 1 to cardiac cycle 11) are output within this cardiac cycle. On the other hand, the second cardiac cycle from the left is the shortest, and eight frame images (cardiac cycle 1 to cardiac cycle 8) are output. In the third cardiac cycle from the left, ten frame images (cardiac cycle 1 to cardiac cycle). Period 10) is output.

  In this way, when the cardiac cycle is not constant, it is impossible to align the cardiac phase numbers in all cardiac cycles in cardiac phases with a large number. In such a case, a method of forcibly aligning with the largest number of cardiac phases or a method of forcibly aligning with the smallest number of cardiac phases can be considered.

  In the former method, in the cardiac cycle in which the number of cardiac phases is insufficient, the two-dimensional beam data having the insufficient cardiac phase number is supplemented by using the two-dimensional beam data having the largest cardiac phase number in the cardiac cycle, etc. Can be considered.

  In the latter method, in the cardiac cycle in which the number of cardiac time phases is excessive, processing such as discarding the two-dimensional beam data having the excessive cardiac phase number can be considered. FIG. 9E shows the latter method, that is, the process of discarding the two-dimensional beam data having the extra cardiac phase number.

  As a method for extracting the two-dimensional beam data of the same phase, there has conventionally been a method itself using an ECG trigger signal obtained from an electrocardiogram waveform (also referred to as an ECG waveform) of a subject. In a conventional ultrasonic diagnostic apparatus using a TEE probe, when one ECG trigger signal is input, the one-dimensional array is rotated by a predetermined angle (for example, 10 degrees), and then the rotation is temporarily stopped. Thereafter, another ECG is stopped. When a trigger signal is input, a method of further rotating the same angle and then stopping the rotation is used. According to this method, two-dimensional beam data of the same time phase becomes spatially equidistant images.

  However, this method repeats the rotation and stop of the one-dimensional array, and the stop period is one cycle or more of the ECG trigger signal. For this reason, it takes a long time to obtain a three-dimensional image.

  On the other hand, in the ECG method in the ultrasonic diagnostic apparatus 1 according to the present embodiment, as described above, the one-dimensional array 12 is always continuously rotated, two-dimensional beam data generated during the continuous rotation, and the A three-dimensional image is synthesized based on the rotation angle information of the one-dimensional array 12 when the two-dimensional beam data is obtained. For this reason, it is possible to generate a three-dimensional image of the entire subject in a shorter time than the conventional method described above.

  As described above, according to the ultrasonic diagnostic apparatus 1 and the control method thereof according to the present embodiment, in the ultrasonic diagnostic apparatus that generates a three-dimensional image while rotating a one-dimensional array, the ultrasonic diagnosis in a three-dimensional space is performed. The arrangement of the sound beam can be made more uniform, and a three-dimensional image of the beating heart can be generated in a shorter 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 constituent elements 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.

DESCRIPTION OF SYMBOLS 1 Ultrasonic diagnostic apparatus 10 Ultrasonic probe 12 One-dimensional array 40 Image generation part 41 Two-dimensional data generation part 42 Image extraction part 43 Three-dimensional image generation part 44 Heart cycle estimation part 50 Beam scanning part 60 ECG detection part

Claims (14)

An ultrasonic transducer is provided with a one-dimensional array in which the ultrasonic transducer is arranged one-dimensionally, and the one-dimensional array is configured to be rotatable with respect to an axis that passes through the center of the one-dimensional array and is orthogonal to the arrangement plane of the ultrasonic transducer. An ultrasonic probe,
A beam scanning unit that two-dimensionally scans the ultrasonic beam formed by the one-dimensional array during rotation of the one-dimensional array;
An image generation unit that generates two-dimensional beam data from echo signals obtained by the two-dimensional scanning, and further generates a three-dimensional image by combining a plurality of the two-dimensional beam data obtained by rotation of the one-dimensional array; With
In the three-dimensional space obtained by the rotation of the one-dimensional array and the two-dimensional scanning, the beam scanning unit has an arrangement density of the ultrasonic beams in a space near the rotation axis of the one-dimensional array, and Scanning the ultrasonic beam so that the difference from the arrangement density of the ultrasonic beam in a space farther in the radial direction than the space is reduced,
An ultrasonic diagnostic apparatus. The beam scanning unit performs sector scanning with the ultrasonic beam, and scans with an interval between the ultrasonic beams on a scanning surface of the sector scanning being non-uniform.
The ultrasonic diagnostic apparatus according to claim 1. The beam scanning unit scans the ultrasonic beam in a region away from the center of the sector scan at a closer interval than a region near the center.
The ultrasonic diagnostic apparatus according to claim 2. The beam scanning unit performs two-dimensional scanning a plurality of times so that one sector scanning range is shared by a plurality of partial sector scans, thereby increasing the number of two-dimensional scanning planes that radially cut the three-dimensional space. ,
The ultrasonic diagnostic apparatus according to claim 1. The beam scanning unit scans the ultrasonic beam so as to be uniformly distributed in the radial direction of the three-dimensional space in the plurality of partial sector scans in which the one sector scan is shared and two-dimensionally scanned. To
The ultrasonic diagnostic apparatus according to claim 4. The beam scanning unit performs scanning so that the number of beams of the ultrasonic beam included in the one sector scan is equal to the total number of beams of the ultrasonic beam included in the plurality of partial sector scans.
The ultrasonic diagnostic apparatus according to claim 4. The image generation unit
Can generate a three-dimensional image of a living heart,
The cardiac cycle is obtained from the periodic variation of the two-dimensional beam data,
Extracting a plurality of two-dimensional beam data of the same cardiac time phase based on the cardiac cycle from a plurality of two-dimensional beam data obtained by rotating the one-dimensional array, and extracting the extracted two-dimensional beam of the same cardiac time phase Combining the beam data to generate the three-dimensional image;
The ultrasonic diagnostic apparatus according to claim 1, wherein the ultrasonic diagnostic apparatus is characterized in that The image generation unit
Can generate a three-dimensional image of a living heart,
Generating a trigger signal synchronized with a cardiac cycle from an electrocardiographic waveform obtained from the living body,
Based on the trigger signal, a plurality of two-dimensional beam data having the same cardiac phase are extracted from a plurality of two-dimensional beam data obtained by rotating the one-dimensional array, and a plurality of two-dimensional beams having the same cardiac phase extracted. Combining the beam data to generate the three-dimensional image;
The ultrasonic diagnostic apparatus according to claim 1, wherein the ultrasonic diagnostic apparatus is characterized in that The image generation unit
The extracted two-dimensional beam data of the same cardiac time phase are arranged and synthesized according to rotation angle information of the one-dimensional array when each two-dimensional beam data is obtained, and the three-dimensional image is generated.
The ultrasonic diagnostic apparatus according to claim 8. The image generation unit
Generating a moving image of the heart as a three-dimensional image by sequentially outputting the three-dimensional images of different cardiac phases in time series;
The ultrasonic diagnostic apparatus according to claim 7. The image generation unit
Generating a moving image of the heart as a three-dimensional image by sequentially outputting the three-dimensional images of different cardiac phases in time series;
The ultrasonic diagnostic apparatus according to claim 8. Using an ultrasonic probe having a one-dimensional array in which ultrasonic transducers are arranged in a one-dimensional manner, the one-dimensional configuration with respect to an axis passing through the center of the one-dimensional array and perpendicular to the arrangement plane of the ultrasonic transducers The array rotates,
Two-dimensional scanning of the ultrasonic beam formed by the one-dimensional array during rotation of the one-dimensional array;
Generating two-dimensional beam data from echo signals obtained by the two-dimensional scanning, and further generating a three-dimensional image by combining the plurality of two-dimensional beam data obtained by rotation of the one-dimensional array,
In the two-dimensional scanning step, in the three-dimensional space obtained by the rotation of the one-dimensional array and the two-dimensional scanning, the array density of the ultrasonic beams in the space near the rotation axis of the one-dimensional array, and the rotation axis Scanning the ultrasonic beam so that a difference with the arrangement density of the ultrasonic beam in a space farther in the radial direction than a nearby space is small;
A method for controlling an ultrasonic diagnostic apparatus. The step of generating the three-dimensional image can generate a three-dimensional image of a living heart,
The cardiac cycle is obtained from the periodic variation of the two-dimensional beam data,
Based on the cardiac cycle, a plurality of two-dimensional beam data having the same cardiac phase are extracted from a plurality of two-dimensional beam data obtained by rotating the one-dimensional array. Combining the beam data to generate the three-dimensional image;
The method according to claim 12, further comprising a step. The step of generating the three-dimensional image can generate a three-dimensional image of a living heart,
Generating a trigger signal synchronized with a cardiac cycle from an electrocardiographic waveform obtained from the living body,
Based on the trigger signal, a plurality of two-dimensional beam data having the same cardiac phase are extracted from a plurality of two-dimensional beam data obtained by rotating the one-dimensional array, and a plurality of two-dimensional beams having the same cardiac phase extracted. Combining the beam data to generate the three-dimensional image;
The method for controlling an ultrasonic diagnostic apparatus according to claim 12, further comprising a step.

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