JP2018138270A - Ultrasound diagnostic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasound diagnostic device capable of improving the quality of a medical image generated by setting a raster count and the number of planes using raster density and plane density with regard to condition setting in performing volume scan.SOLUTION: In some embodiments, an ultrasound diagnostic device has an ultrasound probe, an operation unit, an ultrasound transmission/reception unit, and a medical image generation unit. The ultrasound probe transmits/receives ultrasound to do scanning in mutually crossing first and second directions. An operation unit acquires information on a portion to be scanned, and on the basis of the acquired information on the portion, sets a scan angle for each of the first and second directions. The ultrasound transmission/reception unit transmits/receives ultrasound, using the number of rasters and the number of planes based on the scan angles determined by the operation unit. The medical image generation unit generates a medical image on the basis of the ultrasound received by the ultrasound transmission/reception unit.SELECTED DRAWING: Figure 2

Description

  Embodiments described herein relate generally to an ultrasonic diagnostic apparatus.

  The ultrasound diagnostic apparatus obtains a two-dimensional tomographic image of a subject by transmitting and receiving ultrasound to and from the subject via an ultrasound probe and converting the amplitude of the received reflected wave into luminance. Furthermore, in the case of volume scanning, a plurality of two-dimensional tomographic images scanned at spatially different positions are obtained by moving the ultrasonic probe in a direction orthogonal to the two-dimensional tomographic image obtained at this time. Can be obtained. By arranging these two-dimensional tomographic images three-dimensionally, a three-dimensional image can be displayed on the ultrasonic diagnostic apparatus.

  In order to perform volume scanning, for example, scanning conditions such as scanning angle, swing angle, or volume rate, scanning depth, focus, pulse repetition frequency (prf) transmission frequency, or sound field are used. It is necessary to set various parameters such as transmission / reception conditions. For example, scan conditions, transmission / reception conditions, and the like are stored (set) in the ultrasonic diagnostic apparatus in advance, and are read and used when actually scanning the subject.

JP 2012-005601 A

  However, the invention disclosed in Patent Document 1 does not give consideration to the following points.

  That is, the number of rasters in the scanning direction and the number of planes in the swinging direction necessary for performing the volume scan must be set for each of the above-described scanning conditions, transmission / reception conditions, and the like, and the processing is complicated.

  In addition, since the ratio between the number of rasters and the number of planes is set in advance, when the subject is scanned based on the result of the setting process, the image quality of the medical image displayed as a result of the scan in some cases However, there may be a case where the medical staff who is the operator of the ultrasonic diagnostic apparatus cannot maintain the level originally planned.

  Further, coupled with the automatic setting of the number of rasters and the number of planes, the operator often cannot perform an operation to balance the resolution of each section in the scanning direction and the swinging direction. For this reason, depending on the part to be scanned, an appropriate medical image may not be generated and the medical image may be difficult for the operator to view.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to set the number of rasters and the number of planes using the raster density and the plane density with respect to setting conditions for performing the volume scan. Accordingly, it is possible to improve the image quality of the generated medical image.

  The ultrasonic diagnostic apparatus in the embodiment includes an ultrasonic probe, a calculation unit, an ultrasonic transmission / reception unit, and a medical image generation unit. The ultrasonic probe transmits and receives ultrasonic waves so that the ultrasonic waves are scanned in a first direction and a second direction intersecting each other. The calculation unit acquires information about a part to be scanned, and sets each scan angle in the first direction and the second direction based on the acquired information about the part. The ultrasonic transmission / reception unit transmits and receives ultrasonic waves using the number of rasters and the number of planes based on the scan angle obtained by the calculation unit. The medical image generation unit generates a medical image based on the ultrasonic waves received by the ultrasonic transmission / reception unit.

It is a block diagram which shows the internal structure of the ultrasonic diagnosing device in embodiment. It is a block diagram which shows the internal structure of the calculating part of an ultrasonic diagnosing device. 5 is a flowchart illustrating a flow of calculating a raster number and a plane number and generating a medical image in the ultrasonic diagnostic apparatus. It is explanatory drawing for demonstrating the concept about the number of rasters and the number of planes. It is explanatory drawing for demonstrating that the volume data required for every site | part used as a scanning object differ. It is explanatory drawing for demonstrating that the volume data required for every site | part used as a scanning object differ. It is an example of a screen which shows the example of the medical image displayed on the display part of an ultrasonic diagnosing device. 6 is a screen example illustrating a display example of a medical image generated without using the number of rasters and the number of planes calculated in the embodiment. 6 is a flowchart showing a flow of generating a medical image by calculating the number of rasters and the number of planes in the ultrasonic diagnostic apparatus after setting the raster density and the plane density to 1: 1. 10 is a screen example illustrating a display example of a medical image generated using the number of rasters and the number of planes calculated in the embodiment. 6 is a flowchart showing a flow of generating a medical image by calculating the number of rasters and the number of planes using another method in the ultrasonic diagnostic apparatus. 12 is a screen example illustrating a display example of a medical image generated according to the flow of the flowchart illustrated in FIG. 11. 6 is a flowchart showing a flow of generating a medical image by calculating the number of rasters and the number of planes using still another method in the ultrasonic diagnostic apparatus. 6 is a flowchart showing a flow of generating a medical image by calculating the number of rasters and the number of planes in order to maintain the image quality when changing the volume rate in the ultrasonic diagnostic apparatus. 6 is a screen example illustrating a display example of a medical image generated without using the number of rasters and the number of planes calculated in the embodiment. 10 is a screen example illustrating a display example of a medical image generated using the number of rasters and the number of planes calculated in the embodiment.

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

  FIG. 1 is a block diagram showing an internal configuration of an ultrasonic diagnostic apparatus 1 in the embodiment. In the ultrasonic diagnostic apparatus 1, a CPU (Central Processing Unit) 1a, a ROM (Read Only Memory) 1b, a RAM (Random Access Memory) 1c, and an input / output interface 1d are connected via a bus 1e. An input unit 1f, a display unit 1g, a communication control unit 1h, and a storage unit 1i are connected to the input / output interface 1d.

  The input / output interface 1d transmits / receives an ultrasonic beam between the driving unit control unit 1j that controls each driving unit constituting the ultrasonic diagnostic apparatus 1 and the subject via the ultrasonic probe P. An ultrasonic transmission / reception unit 1k is connected to a medical image generation unit 1l that generates a medical image based on the transmitted / received ultrasonic beam.

  Further, a calculation unit 10 is connected to calculate the number of rasters and the number of planes necessary for scanning the subject.

  The CPU 1a reads out and executes a boot program for starting the ultrasonic diagnostic apparatus 1 from the ROM 1b based on an input signal from the input unit 1f, and reads out various operating systems stored in the storage unit 1i. The CPU 1a controls various devices based on input signals from an external device not shown in FIG. 1 via the input unit 1f and the input / output interface 1d.

  Further, the CPU 1a reads a program and data stored in the RAM 1c, the storage unit 1i, and the like, loads them into the RAM 1c, and implements a series of processing such as filter processing based on a program command read from the RAM 1c. It is.

  The input unit 1f is configured by an input device such as a keyboard and a dial through which a medical worker who is an operator of the ultrasonic diagnostic apparatus 1 inputs various operations, and creates an input signal based on the operation of the medical worker And transmitted to the CPU 1a via the bus 1e. The ultrasonic diagnostic apparatus 1 may be provided with a dedicated operation panel as well as a keyboard and the like.

  The display unit 1g is a liquid crystal display, for example, and receives an output signal from the CPU 1a via the bus 1e, for example. The display unit 1g is a means for displaying a medical image generated based on data obtained via the ultrasonic probe P, a processing result of the CPU 1a, and the like.

  The communication control unit 1h is a means such as a LAN card or a modem, and is a means that enables the ultrasonic diagnostic apparatus 1 to be connected to a communication network such as the Internet or a LAN. Data transmitted / received to / from the communication network via the communication control unit 1h is transmitted / received to / from the CPU 1a via the input / output interface 1d and the bus 1e as an input signal or an output signal.

  The storage unit 1i is composed of a semiconductor or a magnetic disk, and stores programs and data executed by the CPU 1a. For example, the storage unit 1 i stores various conditions that are set when the subject is scanned using the ultrasonic diagnostic apparatus 1 such as scanning conditions and transmission / reception conditions. An arithmetic expression for calculating the number of rasters and the number of planes based on these conditions is also stored.

  In the ultrasound diagnostic apparatus 1 according to the embodiment of the present invention, an ultrasound image generation program is stored in, for example, the storage unit 1i. The program is installed in the ultrasonic diagnostic apparatus 1 by being read and executed by the CPU 1a.

  The ultrasonic transmission / reception unit 1k executes an ultrasonic scan on the subject via an ultrasonic probe P described later under the control of the CPU 1a. Examples of the ultrasonic scan to be executed include a B mode scan, a color Doppler mode scan, and a Doppler mode scan. Although not shown in FIG. 1, for example, a preamplifier, an analog / digital converter, a reception delay circuit, an adder, and the like are provided in the ultrasonic transmission / reception unit 1 k.

  An ultrasonic probe P that is in direct contact with the subject and acquires information inside the subject through reflection of the ultrasonic wave is connected to the ultrasonic transmission / reception unit 1k. The ultrasonic probe P includes an ultrasonic transducer that transmits and receives ultrasonic waves, and the ultrasonic transducer is driven based on an instruction from the ultrasonic transmission / reception unit 1k. The internal information about the subject collected by the ultrasonic probe P is received as an ultrasonic beam by the ultrasonic transmission / reception unit 1k and sent to the medical image generation unit 1l.

  As the ultrasonic probe P, for example, a mechanical 4D probe or a matrix array probe can be used.

  Although the illustration of the internal configuration of the medical image generation unit 1l is omitted in FIG. 1, the medical image generation unit 11 includes a signal processing unit, an image configuration unit, and an image generation unit therein, and includes an ultrasonic probe P and an ultrasonic transmission / reception unit 1k. A medical image is generated on the basis of the information acquired through the process.

  The signal processing unit performs various signal processing based on the signal received by the reception unit of the ultrasonic transmission / reception unit 1k. Specifically, signal processing corresponding to the above-described scan mode is performed. In the signal processing unit, for example, devices such as an echo data detector, a logarithmic compressor, and a digital filter in the depth, scanning line, and frame directions are provided.

  The image construction unit receives the signal transmitted from the signal processing unit, converts the coordinates of the beam data aligned in the depth direction in the signal processing unit, and converts it to pixel data aligned in the line direction for display. Acts as a scan converter to convert. By performing the processing, image data that is the basis for generating an ultrasonic image is generated.

  The image generation unit generates, for example, a medical image displayed as a two-dimensional image based on the image data generated by the image configuration unit, and generates a three-dimensional medical image based on the two-dimensional medical image. Generate.

  The calculation unit 10 calculates the number of rasters and the number of planes necessary for scanning the subject using the ultrasonic diagnostic apparatus 1. Although details will be described later, the calculation unit 10 calculates the number of rasters and the number of planes based on the raster density and the plane density.

  FIG. 2 is a block diagram illustrating an internal configuration of the calculation unit 10 according to the embodiment. The calculation unit 10 receives a processing request that triggers calculation of the number of rasters and the number of planes, a density calculation unit 12 that calculates raster density and plane density, a determination unit 13, and the calculated raster density and plane. The calculation unit 14 calculates the number of rasters and the number of planes using the density, and the transmission unit 15 transmits the calculated number of rasters and the number of planes to the CPU 1a, for example, so as to use them as scanning conditions.

  The functions and functions of these units will be described in the flow of generating a medical image by scanning the subject based on these conditions after calculating the number of rasters and the number of planes described later.

  Next, a flow in which a medical image is generated based on the calculation of the number of rasters and the number of planes required when scanning the subject using the ultrasonic diagnostic apparatus 1 and the scan performed using the conditions. Will be described below.

  FIG. 3 is a flowchart showing a flow of generating a medical image by calculating the number of rasters and the number of planes in the ultrasonic diagnostic apparatus 1. It is assumed that the ultrasonic probe P used here is a mechanical 4D probe.

  A medical worker who uses the ultrasonic diagnostic apparatus 1 inputs various conditions (parameters) such as a scanning condition and a transmission / reception condition for performing a scan before scanning the subject. The contents of the input information about these parameters are grasped (ST1).

  Here, the medical staff may input all the parameters, or the parameters may be set by using or changing the parameters stored in the storage unit 1i.

  When parameters are input, for example, a medical worker uses a keyboard or the like constituting the input unit 1f, and the input content is displayed on the display unit 1g. When the parameter input is started in this manner, the ultrasonic diagnostic apparatus 1 knows that fact, and therefore, the calculation unit 10 is instructed to input parameters in advance.

  The calculation unit 10 receives the input and confirmed parameters, and calculates the density in the scan direction and the density in the swing direction based on the parameters (ST2). The density in the scan direction is the raster density, and the density in the swing direction is the plane density.

  Here, the meaning of words such as raster (scanning line) and plane (tomographic image) will be described with reference to the drawings. FIG. 4 is an explanatory diagram for explaining the concept of the number of rasters and the number of planes. First, in FIG. 4, a region shown in the front and having an arc shape on the upper and lower sides and a substantially trapezoidal shape is a scan region performed using the ultrasonic diagnostic apparatus 1.

  A raster (scanning line) X is indicated by a solid arrow in this region. A plane Y is generated as one medical image by transmitting and receiving the raster X so as to form a scan region within the range of the scan angle θ1. That is, the shape shown in the substantially trapezoidal shape in FIG. 4 indicates a plane (tomographic image) Y. The number of rasters X transmitted / received when generating one plane Y is the number of rasters.

  A plurality of planes Y can be obtained by scanning with the ultrasonic probe P shifted little by little. The angle at which the ultrasonic probe P is displaced in this way is called the swing angle, and is indicated by the symbol θ2 in FIG. By obtaining volume data that only generates a plurality of planes Y within the range of the swing angle θ2, it is possible to generate a three-dimensional medical image. Here, the number of planes Y generated within the swing angle θ2 is expressed as the number of planes.

  By performing the scan in this way, it is possible to acquire volume data of a part to be examined of the subject. However, the shape of the volume data acquired may differ depending on the part to be examined.

  FIG. 5 and FIG. 6 are explanatory diagrams for explaining that the volume data required for each part to be scanned is different.

  For example, when the examination target is a uterus or a fetal spine, the required volume data has a wide and narrow (thin) shape as shown in FIG. Accordingly, the volume data obtained is such that the scan angle θ1 is larger than the swing angle θ2.

  On the other hand, when the test object is, for example, a fetal heart, the shape shown by the same width and thickness as shown in FIG. For this reason, the obtained volume data has substantially the same scan angle θ1 and swing angle θ2.

  The volume data obtained in this way is displayed on the display unit 1g of the ultrasonic diagnostic apparatus 1. FIG. 7 is a screen example showing an example of a medical image displayed on the display unit 1 g of the ultrasonic diagnostic apparatus 1.

  As shown in FIG. 7, the display unit 1g is divided into four display areas, and four types of images are displayed. Among these, the volume image obtained is the image displayed in the lower right. The images displayed in the other three regions are cross-sectional views shown by cutting the volume image along a certain cross section.

  In the explanatory view shown in FIG. 4, a raster X and a plurality of planes Y are shown. Here, the scanning direction which is the direction of the raster X is represented by A, and the direction in which a plurality of planes Y are photographed perpendicular to the scanning direction A, that is, the swinging direction is B. Further, a direction orthogonal to the scanning direction A and the swinging direction B is represented as C.

  In the display unit 1g shown in FIG. 7, a tomographic image shown by cutting the volume image in each direction is displayed. That is, the tomographic image (A surface) in the scanning direction A is displayed in the upper left display area of the display unit 1g in FIG. 7, and the tomographic image (B surface) in the swing direction B is displayed in the upper right display area. . In the lower left area, a tomographic image (plane C) obtained by cutting in the direction C shown in FIG. 4 is displayed.

  It should be noted that the medical staff using the ultrasound diagnostic apparatus 1 can arbitrarily set the layout including the size of each display area of the display unit 1g and what image to display in which display area. Is possible.

  When the density calculation unit 12 calculates the density of the raster X in the scanning direction A (raster density) and the density of the plane Y in the swinging direction B (plane density), the calculation result is transmitted to the determination unit 13, and the density of both is calculated. Is determined to be 1: 1 (ST3). That is, here, the image quality of the display image is improved by adjusting the raster density and the plane density to be 1: 1.

  If it is determined that the calculated raster density and plane density are in a ratio of 1: 1 (YES in ST3), that fact is sent to the calculation unit 14, and the raster is calculated using these calculated densities. The number and the number of planes are calculated (ST4). The calculation unit 14 calculates the number of rasters, the number of planes, and the time required to acquire one volume data when performing a volume scan using the following formula 1 as a basic formula.

  Here, assuming that the number of rasters in the scanning direction is X1, the number of planes in the swinging direction B is X2, the pulse transmission interval is t, and the time α to be taken into account for switching the vibration direction is one when performing volume scanning. A time T necessary for acquiring the volume data can be calculated. Then, the number of rasters X1 and the number of planes X2 necessary for calculating this time T are calculated using the equations shown in equation (1). In the embodiment of the present invention, the raster density k1 or the plane density k2 is used for calculating the number of rasters X1 or the number of planes X2.

  Here, the scan angle is θ1, the swing angle is θ2, the raster density is k1, the plane density is k2, and the correction function is f (y). In the process of generating and displaying a volume image, the correction function f (y) is, for example, in view of the fact that there is a process that cannot accurately represent the number of rasters using only the volume rate and prf, such as a compound process. The purpose is to correct in such cases.

  The subject is scanned using the raster number X1 and the plane number X2 calculated in this way (ST5). As a result of scanning, a volume image, which is a medical image, is generated in the medical image generation unit 11 (ST6) and displayed on the display unit 1g. The display unit 1g displays not only a volume image but also a cross-sectional view showing a state cut along the A-plane, B-plane, and C-plane as shown in FIG.

  By looking at the generated and displayed medical images, the medical staff who is the operator confirms whether or not the image intended by himself / herself is displayed. In other words, the medical staff looks at the displayed image and determines whether or not the setting of the displayed image, and thus the parameters (raster density, plane density) for image generation, is appropriate. In the ultrasonic diagnostic apparatus 1, for example, whether a displayed image is appropriate by displaying a confirmation screen such as a pop-up that asks a medical worker whether the image is an appropriate image and causing the medical worker to select it. It is determined whether or not (ST7).

  In the ultrasonic diagnostic apparatus 1, for example, it is detected that a medical worker has performed a process for confirming the determination on the confirmation screen, and it is determined whether or not the displayed medical image is appropriate. If it is displayed (YES in ST7), the shooting is continued as it is (ST8). If the image is not appropriate (NO in ST7), various parameters are input again. The raster density and the plane density are calculated again.

  FIG. 7 is a screen example showing an example of a medical image displayed on the display unit 1g of the ultrasonic diagnostic apparatus 1 as described above. The tomographic image shown here is in a state where the raster density and the plane density are approximately 1: 1. Therefore, when viewing the screen example, the tomographic image of the A plane displayed in the upper left and the upper right are displayed. The B-plane tomographic image is displayed with good image quality. In addition, since the tomographic images displayed on the A and B planes have good image quality, they are displayed in a balanced manner when the entire screen is viewed.

  On the other hand, when the determination unit 13 confirms the ratio between the raster density and the plane density and the density is not 1: 1 (NO in ST3), a medical image with good image quality is generated as it is. It is judged that it is not possible.

  FIG. 8 is a screen example showing a display example of a medical image generated without using the number of rasters and the number of planes calculated in the embodiment. That is, it is an example of a screen when there is a difference in image quality between the tomographic image showing the A plane and the tomographic image showing the B plane.

  In the case of the screen example shown in FIG. 8, since the plane density is higher than the raster density, the resolution of the B plane is higher than the resolution of the A plane. Therefore, unlike the screen example shown in FIG. 7, if the ratio between the raster density and the plane density is in an unbalanced state, for example, the tomographic image on the B surface is clearly displayed, but the tomographic image on the A surface has a rough image quality. It will be displayed. Of course, it is possible to improve only the image quality of either side, but considering the generation of tomographic images for the necessary area of the normal volume image, the image quality of at least the A-side and B-side tomographic images is generally uniform. It is easier to see.

  The visibility is such that the raster density and the plane density are well balanced, that is, close to 1: 1, so that the number of rasters and the number of planes are set appropriately and then scanned and displayed. Achieved by: Therefore, the calculation unit 10 of the ultrasonic diagnostic apparatus 1 corrects the scan angle θ1 and the swing angle θ2 that are one of the parameters so that the raster density and the plane density are 1: 1 (ST9), As a result, the raster density and the plane density are 1: 1. Of course, even if the correction is automatically performed, the parameter input by the medical staff or the like is not fundamentally corrected.

  As described above, as shown in the screen example of FIG. 8, the raster density and the plane density are set to 1: 1 by eliminating the imbalance in the tomographic image and appropriately correcting the parameters input by the ultrasonic diagnostic apparatus 1. Explained the process of approaching.

  On the other hand, instead of correcting the input parameters, the ratio of the raster density to the plane density is automatically set to 1: 1 by the ultrasonic diagnostic apparatus 1, and the number of rasters and the plane are set under the conditions. A process for calculating the number of sheets is also conceivable.

  FIG. 9 is a flowchart showing a flow of generating a medical image by calculating the number of rasters and the number of planes in the ultrasonic diagnostic apparatus 1 after setting the raster density and the plane density to 1: 1. In the flowchart shown in FIG. 9, the same steps as those in the flowchart shown in FIG.

  First, the values of various parameters input in the ultrasonic diagnostic apparatus 1 are grasped (ST1). The determination unit 13 extracts the scan angle and the swing angle from the input parameters (ST11). Then, the angle between the two is confirmed (ST12). Here, the scan angle and the rocking angle are confirmed when the two are greatly different from each other, the raster density and the plane density are different from each other. As a result, the tomographic image in the scan direction displayed on the display unit 1g. This is because there is a possibility that the image quality of the (A surface) and the tomographic image (B surface) in the swing direction may be unbalanced.

  If the determination unit 13 confirms the scan angle and the swing angle and the two angles are greatly different (YES in ST12), the values of the raster density k1 and the plane density k2 are obtained in advance as shown in Equation (2). Is set to be equal (ST13).

  Then, if the relationship of the formula (2) is reflected in the above-described formula (1), the following formula (3) can be obtained.

  By using equation (3) using the set raster density k1 and plane density k2, the number of rasters X1 and the number of planes X2 are calculated from the scan time T and the pulse repetition frequency (prf) t. (ST14). The subject is scanned based on the raster number X1 and the plane number X2 calculated in this way, and a medical image is generated (ST5, ST6). The subsequent processing is as described above.

  In this way, by automatically setting the raster density k1 and the plane density k2 so that k1 = k2, for example, the imbalance between the A side and the B side shown in the screen example of FIG. 8 is eliminated. be able to.

  Here, FIG. 10 is a screen example illustrating a display example of a medical image generated using the number of rasters and the number of planes calculated in the embodiment. That is, when compared with the screen example shown in FIG. 8, there is no imbalance between the quality of the screens of the A side and the B side, and the A side is displayed with the same image quality as the B side. become. This is because the unbalance between the scan angle and the swing angle is taken into account in the equation (3).

  If the determination unit 13 compares the scan angle with the swing angle and there is no significant difference between the two angles (NO in ST12), the raster density k1 and the plane are based on the parameters input as before. The density k2 is calculated (ST2), and the number of rasters and the number of planes are calculated using the density (ST14 and later).

  Next, another method of calculating the number of rasters and the number of planes using the raster density k1 and the plane density k2 as described above will be described.

  FIG. 11 is a flowchart showing a flow of generating a medical image by calculating the number of rasters and the number of planes using another method in the ultrasonic diagnostic apparatus 1. In the flowchart shown in FIG. 11, the same number of steps is shown for the same processing as the flowcharts shown so far.

  Here, an appropriate number of rasters and the number of planes are obtained based on the absolute values of the calculated raster density k1 and plane density k2. The specific flow of calculating the number of rasters and the number of planes is as follows.

  First, the values of various parameters input by a medical worker or the like are grasped, and the density calculation unit 12 calculates the raster density and the plane density using these values (ST1, ST2). These processes are as described above.

  The determination unit 13 receives the values of the calculated raster density and plane density and grasps the absolute values of both (ST21). After that, the absolute values of the two densities thus grasped are compared with a reference absolute value (ST22). The absolute value used as a reference here is a value that can generate an appropriate medical image with image quality maintained by calculating the number of rasters and the number of planes using the value as a density. The lower limit is shown as the density that can maintain the image quality. Therefore, the reference absolute value is preset in the storage unit 1i, for example. The determination unit 13 compares the calculated raster density with the plane density using the reference absolute value.

  As a result, if the absolute values of the calculated raster density and plane density do not take a value greater than or equal to the reference absolute value (NO in ST23), the reference absolute value is used instead of the calculated density absolute value. (ST24).

  In other words, if a value smaller than the reference absolute value is adopted as the raster density or plane density, the image quality cannot be maintained, for example, the screen becomes rough, or the image quality of the A side and the B side becomes unbalanced. Will get. Therefore, the reference absolute value set so that the minimum image quality can be maintained is used as the density when calculating the number of rasters and the number of planes.

  On the other hand, as a result of comparing the calculated density with the reference absolute value by the determination unit 13, if the calculated density value indicates a value greater than or equal to the reference absolute value (YES in ST23), the density calculation unit 12 Using the raster density k1 and plane density k2 calculated in step 1, the number of rasters and the number of planes are calculated.

  Thereafter, using the selected or calculated raster density k1 and plane density k2, the number of rasters and the number of planes are calculated using the above-described equations (ST15), and the scan of the subject is performed based on the values. Is done. As a result, based on the obtained volume data, a volume image and a tomographic image at a set cross section are displayed on the display unit 1g (ST5 and below).

  FIG. 12 is a screen example showing a display example of a medical image generated according to the flow of the flowchart shown in FIG. Normally, when the volume rate is increased, the screen display becomes rough and the image quality is lowered. However, even if the volume rate is increased by performing the above-described processing using the absolute values of the raster density and the plane density. The same image quality as when the volume rate is low can be maintained.

  For example, in the images shown in FIGS. 7 and 10, the volume rate is set to 2 vps (volume per second). From this state, the volume rate is simply increased to, for example, 6 vps, and the same processing is performed so far. When an image is displayed, the image quality decreases.

  However, as described above, using the processing flow shown in FIG. 11 to calculate the number of rasters and the number of planes based on the absolute values of the raster density and the plane density and perform scanning, the volume rate is increased. Nevertheless, as in the image shown in FIG. 12, it is possible to maintain an image quality comparable to that of the image before increasing the volume rate shown in FIG. 7 or FIG.

  Here, the absolute values of both the raster density and the plane density are compared with the reference absolute value. The advantages of adopting this processing method are as described above, but the balance between the image quality of the A-side image affected by the number of rasters and the B-side image affected by the number of planes is not considered. Therefore, for example, by performing processing as follows, it is possible to prevent both the A side and the B side from being unbalanced in image quality.

  FIG. 13 is a flowchart showing a flow of generating a medical image by calculating the number of rasters and the number of planes using still another method in the ultrasonic diagnostic apparatus 1. Here, there is a point in the processing when the raster density and the plane density do not take values exceeding the reference absolute value. In the flowchart shown in FIG. 13, the same number of steps is shown for the same processing as the flowcharts shown so far.

  That is, when the raster density and the plane density are smaller than the reference absolute value, the reference absolute value is used instead of the calculated density when calculating the number of rasters and the number of planes (ST24). However, in such a case, when both the raster density and the plane density are smaller than the reference absolute value, or when either the raster density or the plane density is smaller than the reference absolute value. , Both can be considered.

  If both the raster density and the plane density are smaller than the reference absolute value, the reference absolute value is selected for both densities, so it is considered that the density of both is unbalanced. Hateful. On the other hand, if one of the values is smaller than the reference absolute value, but the other has a value greater than or equal to the reference absolute value, the density of the two may be unbalanced.

  Therefore, the determination unit 13 confirms whether or not the raster density and the plane density both have selected absolute values (ST31). As a result of the determination, when either the raster density or the plane density is selected as an absolute value (NO in ST31), by adjusting both values (ST32), when a medical image is generated, It is possible to avoid displaying the image quality unbalanced. Specifically, for example, the following processing is performed.

  For example, the absolute value of the raster density k1 is 20, and the absolute value of the plane density k2 is 8. The reference absolute value is set to 10. In this case, the value of the plane density k2 is smaller than the reference absolute value. Therefore, according to the above-described processing, the reference absolute value of 10 is set as the density (k2 = 10). On the other hand, since the raster density k1 has a value (20) that is equal to or greater than the reference absolute value, the calculated value of the raster density k1 is used as it is.

  However, in addition to the process of using the calculated value as it is, for example, the value before the plane density k2 is set as the reference absolute value, that is, the calculated plane density k2 and the calculated raster You may perform the process which adjusts the value of the raster density k1 so that a ratio with the density k1 may be maintained.

  Alternatively, not only maintaining the displayed image quality, but also considering the balance between the image quality of the A-side image affected by the number of rasters and the B-side image affected by the number of planes, for example, In contrast, the value of the raster density k1 having a value equal to or greater than the reference absolute value is not used as it is, but an adjustment method in which the value of the raster density k1 is set to 18, for example, is adopted in consideration of the value of the plane density k2. be able to.

  In this way, when there is a possibility that an imbalance in image quality may appear when either the raster density or the plane density is selected as an absolute value, the value is adjusted after adjusting the balance between the two. Then, processing is performed to calculate the number of rasters and the number of planes (ST33).

  On the other hand, if an absolute value is selected for both (YES in ST31), processing is performed so as to calculate the number of rasters and the number of planes with that value (ST33).

  As described above, the density value calculated not only by simply comparing the value of the raster density k1 and the value of the plane density k2 with the reference absolute value but also considering the balance between them is the reference absolute value. In spite of the above values, adjustment is made such that the value is lowered to balance the image quality of the A-side image affected by the number of rasters and the B-side image affected by the number of planes. be able to.

  As described above, when the processing is performed so that the raster density k1 and the plane density k2 are as close as possible to 1: 1, the image of the A surface affected by the number of rasters and the image of the B surface affected by the number of planes are reduced. Image quality can be improved. On the other hand, when the volume rate is increased, the scan time T per volume is shortened. Therefore, it is impossible to obtain a sufficient number of rasters to generate one volume image. Therefore, by taking the absolute values of the raster density k1 and the plane density k2 and comparing them with the reference absolute value, the same image quality as before can be maintained even when the volume rate is set high.

  The above processing is performed on the premise that, for example, the scanning lines are isotropically, that is, the scanning lines are evenly emitted in the scanning direction A or the swinging direction B (the density is made uniform). However, depending on the inspection, for example, there may be a case where it is desired to increase the number of scanning lines in a specific direction in the scanning direction A and perform scanning.

  For example, when the above-described setting for increasing the volume rate is made, if there is no allowance under the condition that the raster density k1 is isotropic, the image on the A plane and the number of planes affected by the number of rasters will be There may be a case where the image quality of the affected B-side image is poor and a medical worker cannot obtain a resolution necessary for diagnosis. Therefore, as one of the allowances, it is possible to maintain and improve the image quality under the condition that the raster density k1 is isotropic by performing the processing using the absolute value as described above.

  The allowance is not limited to this method, and another method is conceivable. That is, the processing method described below maintains and improves image quality in the same manner even when scanning is performed with intentionally increasing the number of scanning lines in a specific direction without making the raster density k1 isotropic, for example. The effect of aiming can be obtained.

  FIG. 14 is a flowchart showing a flow of generating a medical image by calculating the number of rasters and the number of planes in order to maintain the image quality when the volume rate is changed in the ultrasonic diagnostic apparatus 1. Here, the description will be made on the assumption that the raster density k1 is intentionally changed instead of the plane density k2. Further, in the flowchart shown in FIG. 14, the same number of steps is shown for the same processing as the flowcharts shown so far.

  A characteristic point in the processing described here is that an upper limit value and a lower limit value of density are provided in advance, and the set upper limit value and lower limit value are respectively compared with the calculated raster density k1 and plane density k2. .

  The flowchart shown in FIG. 14 will be described. First, the parameters input to the ultrasonic diagnostic apparatus 1 by a medical worker or the like are grasped, and the density (raster in the scan direction A) is used by the calculation unit 10 using the parameters. The density k1) and the density in the swing direction B (plane density k2) are calculated (ST1, ST2).

  Next, the raster density k1 and the plane density k2 calculated by the density calculation unit 12 are compared with an upper limit value kmax and a lower limit value kmin that are determined in advance by the determination unit 13 (ST41). These upper limit value kmax and lower limit value kmin are stored in advance in the storage unit 1i, for example.

  As a result of comparison, when the values of the raster density k1 and the plane density k2 exceed the threshold value that is the upper limit value kmax or the lower limit value kmin (YES in ST42), the determination unit 13 then determines which surface, that is, the scan direction. In the upper right display area of the tomographic image (A surface) in A, it is confirmed which resolution of which surface of the tomographic image (B surface) in the swing direction B is important (ST43).

  Here, the determination unit 13 determines which resolution of the A-plane and B-plane is important by comparing the magnitudes of the scan angle θ1 and the swing angle θ2 (ST44). In other words, the fact that the angle shows a large value means that the medical staff wants to see a wider range, and therefore the image quality in such a tomographic image is improved.

  For example, when the shape of the volume data acquired by scanning is a wide and narrow (thin) shape as shown in FIG. 5, the scan angle θ1 is larger than the swing angle θ2. Therefore, in such a case, it can be inferred that the A plane that is the tomographic image in the scanning direction A is the tomographic image that the medical staff wants to see rather than the B plane that is the tomographic image in the swinging direction B. Processing is performed to increase the resolution of the tomographic image. In the following, a specific tomographic image that places importance on resolution is referred to as “tomographic image α” for convenience, and other tomographic images are referred to as “tomographic image β” for convenience.

  Then, as a result of the determination unit 13 comparing the scan angle θ1 and the swing angle θ2 to determine which surface is important for resolution, the density of the tomographic image β on the surface with a smaller angle is determined as the lower limit. The value kmin is set (ST45).

  The calculation unit 14 obtains the number of rasters X1 and the number of planes X2 based on the density set by the determination unit 13 (ST46). The formula used at this time is the following formula (4).

  By using Expression (4), the number of rasters X1 and the number of planes X2 can be obtained using the density of the tomographic image β on the surface having a smaller angle set as the lower limit value kmin. The subject is scanned using the calculated number of rasters X1 and the number of planes X2, and a medical image is generated based on the acquired information (ST6, ST7). The generated medical image is displayed on the display unit 1g, and after confirmation by the medical staff (ST8), the raster density k1 and the plane density k2 are set again, or imaging is continued as it is (ST9). .

  Here, FIG. 15 is a screen example showing a display example of a medical image generated without using the number of rasters and the number of planes calculated in the embodiment. On the other hand, FIG. 16 is a screen example showing a display example of a medical image generated using the number of rasters and the number of planes calculated in the embodiment.

  As is clear from the screen example shown in FIG. 15, if the processing for increasing the volume rate is performed without taking care of it, the image quality on the A and B surfaces deteriorates, and the resolution necessary for diagnosis can be obtained. Absent.

  On the other hand, when a medical image is generated and displayed using the number of rasters X1 and the number of planes X2 calculated using the above-described equation (4), as shown in the screen example of FIG. The resolution of the surface has increased significantly. As described above, this is because the resolution of the A plane is more important than the B plane of the tomographic image β. However, with respect to the resolution of the B surface, as the resolution of the A surface is improved, a higher resolution than the B surface of the screen example shown in FIG. 15 can be obtained.

  Here, the determination of which resolution of the A-plane and B-plane is important is performed by comparing the scan angle θ1 and the swing angle θ2, but a method for selecting a tomographic image α that emphasizes resolution is used. For example, it may be determined by using image recognition technology whether the resolution increases when more scanning lines are output in any direction.

  In addition, the ultrasonic diagnostic apparatus 1 can automatically adjust the density balance between the tomographic image α that emphasizes the resolution and the tomographic image β that does not so, based on instructions from the medical staff, and perform the adjustment. Thus, a more balanced image quality can be obtained on the screen. In the case of an instruction by a medical worker, for example, a plurality of types of patterns indicating the ratio of the respective plane densities may be set in advance, and the pattern may be selected from the patterns.

  As described above, regarding the setting of conditions for performing a volume scan, it is possible to improve the image quality of a generated medical image by setting the number of rasters and the number of planes using the raster density and plane density. An ultrasonic diagnostic apparatus can be provided.

  Further, by combining the processing for balancing the displayed tomographic images, it is possible to generate and display a medical image in consideration of the display balance of the entire screen in addition to improving the image quality.

  Furthermore, the description has been made on the assumption that the ultrasonic probe P used in the ultrasonic diagnostic apparatus 1 is a mechanical 4D probe. However, the ultrasonic probe P is not limited to a mechanical 4D probe, and for example, a matrix array probe can also be used. When the matrix array probe is used, the scanning direction when using the mechanical 4D probe is the azimuth direction and the swinging direction is the elevation direction, but the processing flow and contents are as described above. That is, by setting the number of rasters and the number of planes using the raster density and the plane density, the image quality for the generated medical image can be improved.

  So far, the description has been given of improving the image quality of a generated medical image by automatically setting the number of rasters and the number of planes using the raster density and the plane density. However, for example, the optimum raster density and plane density for the part to be scanned may be set in the ultrasonic diagnostic apparatus 1 for each part in advance. In this case, the optimal raster density and plane when the selected part is scanned, for example, by selecting a part icon displayed on the display unit in consideration of the part to be scanned by the medical staff. Density can be set.

  Although an embodiment of the present invention has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. This embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Ultrasonic diagnostic apparatus 10 Operation part 11 Reception part 12 Density calculation part 13 Judgment part 14 Calculation part 15 Transmission part

Claims (3)

An ultrasonic probe that transmits and receives the ultrasonic waves so as to scan in a first direction and a second direction in which the ultrasonic waves intersect each other;
A calculation unit that acquires information about a part to be scanned, and sets each scan angle in the first direction and the second direction based on the acquired information about the part;
An ultrasonic transmission / reception unit that transmits and receives ultrasonic waves using the number of rasters and the number of planes based on the scan angle obtained by the calculation unit;
A medical image generation unit that generates a medical image based on the ultrasonic wave received by the ultrasonic transmission / reception unit;
An ultrasonic diagnostic apparatus comprising:   The ultrasonic diagnostic apparatus according to claim 1, wherein scanning in the first direction and the second direction is performed by two-dimensionally arranged ultrasonic transducers.   The ultrasonic diagnostic apparatus according to claim 1, wherein scanning in the first direction and the second direction is performed by swinging a one-dimensionally arranged ultrasonic transducer in a direction orthogonal to the arrangement direction.