JP3628158B2 - Ultrasonic diagnostic equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to transmission focus control.
[0002]
[Prior art]
In a conventional ultrasonic diagnostic apparatus, transmission focus is performed by adjusting the phase of a transmission signal supplied to each vibration element at the time of transmission, and reception is performed by adjusting the phase of the reception signal from each vibration element at the time of reception. Focus is performed. As one reception focus, reception multi-stage focus is known in which reception focus points are sequentially switched from a deep point to a shallow point in reception for transmission of one ultrasonic pulse. On the other hand, multistage transmission focus is also known, which performs transmission and reception at each transmission focus point.
[0003]
[Problems to be solved by the invention]
Therefore, if the transmission focus point is increased, the resolution is improved and the image quality of the ultrasonic image is improved. However, on the other hand, the number of transmission / reception increases, and the frame rate is lowered. In particular, in an ultrasound diagnosis that requires real-time characteristics such as the heart, a reduction in the frame rate must be avoided.
[0004]
Some conventional ultrasonic diagnostic apparatuses are configured such that the user can set the number and depth of transmission focus. However, the setting can be performed only for the entire beam scanning range. For this reason, if the number of focus points is increased in order to improve the image quality of a specific part, the number of focus points similarly increases at all beam addresses, resulting in a problem that the frame rate is significantly reduced. . In other words, in the conventional apparatus, a necessary number of focus points cannot be appropriately set where necessary.
[0005]
The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to improve the image quality of a site of interest by minimizing a decrease in frame rate as much as possible.
[0006]
Another object of the present invention is to make it possible to control transmission focus for each beam address.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides means for setting a frame rate condition, means for setting a ratio of the number of transmission focus points inside and outside the region of interest, and a region of interest for setting a region of interest on an ultrasound image. setting means and said frame rate conditions, the ratio of the number of the transmission focusing point, and, on the basis of the form of the region of interest, sent to set the number and depth of transmission focus point for each beam address of a transmission beam signal It comprises a setting means, and a transmission control means for controlling the formation of a transmission beam in accordance with the contents set by the transmission setting means. Desirably, the shape of the transmission beam is controlled according to the number of transmission focus points. Desirably, the shape of the transmission beam is controlled so that a beam address having only one transmission focus point is set to broad focus, and the beam address having a plurality of transmission focus points is set to strong focus. The shape of the transmission beam is controlled.
[0008]
According to the above configuration, the number and depth of transmission focus points can be freely set for each beam address, so that the resolution of a desired area can be improved. For example, if the number of transmission focus points is increased by the attention area, the frame rate can be prevented from being lowered as much as possible, and the image quality of the attention area can be improved. For example, even if the attention area exists along the oblique direction, the depth of the transmission focus point can be set along the direction of the attention area.
[0009]
In a preferred aspect of the present invention, the region of interest setting means for setting the region of interest on the ultrasound image is included, and at least one of the number of transmission focus points and the depth is set according to the region of interest. A region of interest (Region Of Interest (ROI)) is usually a region that the user wants to observe most, and a transmission focus is set based on the region. The region of interest is set manually or automatically.
[0010]
In a preferred aspect of the present invention, the region-of-interest setting means is means for causing the user to input the region of interest. For example, a keyboard or a trackball is used as the means.
[0012]
In a preferred aspect of the present invention, the transmission setting means includes transmission focus determination means for determining at least one of the number and depth of the focus points according to the form of the region of interest. That is, the most suitable transmission focus pattern is determined with reference to the form of the region of interest. Here, the region of interest is defined by, for example, a line segment or a two-dimensional region.
[0013]
Preferably, the transmission focus determination unit determines at least one of the number of focus points and the depth based on at least one of a width or a depth of the region of interest for each beam address of the transmission beam. For example, the focus point is set as the midpoint or equal point of the passing range on each beam address in the region of interest.
[0014]
Preferably, the transmission focus determination means sets a transmission focus point at a predetermined depth for a beam address that is out of the region of interest. According to this configuration, a decrease in the frame rate can be prevented as much as possible, and both the image quality and the frame rate of the region to be observed can be achieved.
[0015]
Preferably, the transmission focus determination means determines the number of the focus points according to a set frame rate condition. For example, the transmission focus point is automatically determined so that the actual frame rate is within the lower limit of the frame rate.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.
[0019]
FIG. 1 shows a preferred embodiment of an ultrasonic diagnostic apparatus according to the present invention, and FIG. 1 is a block diagram showing the overall configuration of the apparatus.
[0020]
The probe 10 is an ultrasonic probe used in contact with the surface of a living body or inserted into a body cavity, and ultrasonic waves are transmitted and received by the probe 10. The probe 10 has an array transducer composed of a plurality of transducer elements. An ultrasonic beam is formed by supplying a transmission signal with a predetermined delay amount to each vibration element constituting the array transducer, and the ultrasonic beam is electronically scanned. Similarly, a reception beam is formed by adding a predetermined delay amount to a reception signal from each vibration element constituting the array transducer and performing synthesis addition, and electronic scanning of the reception beam is performed. Incidentally, the present invention is applicable when linear scanning or sector scanning is performed. The present invention can also be applied when other electronic scanning methods are used.
[0021]
The transmission circuit 12 is a circuit that supplies a transmission signal to each vibration element that constitutes the array transducer, and performs predetermined delay control on each transmission signal in order to perform transmission focus as described above. .
[0022]
When a plurality of transmission focus points are set, transmission is performed for each focus point. This is the same as before. In the apparatus of the present embodiment, the number of transmission focus points and the depth thereof are controlled by the control unit 14. For this reason, focus point information is supplied from the control unit 14 to the transmission circuit 12.
[0023]
The number of transmission focus points and their depth are set manually or automatically. In the example shown in FIG. 1, the number and depth of transmission focus points are determined by the input device 16. The input device 16 is, for example, a keyboard or a trackball. The transmission focus control will be described in detail later.
[0024]
In the receiving circuit 18, delay control is performed on the received signals from the respective transducers constituting the array transducer in order to realize so-called reception dynamic focus. This is a known process. A reception signal output from the receiving circuit is input to the image forming circuit 20, and a B-mode tomographic image, a two-dimensional Doppler image, and the like are formed by the image forming circuit 20. The ultrasonic image formed in this way is displayed on the display device 22.
[0025]
The input device 16 also functions as ROI (region of interest) setting input means described later. Of course, the ROI setting may be automatically performed based on the ultrasonic image.
[0026]
In the ultrasonic diagnostic apparatus shown in FIG. 1, the number and depth of transmission focus points can be set individually for each beam address. Therefore, for example, a transmission focus point setting pattern as shown below can be constructed.
[0027]
FIG. 2 shows the ROI 32 set on the ultrasonic image 30. When setting the transmission focus point 34 for such an ROI 32, two transmission focus points 34 are set for each beam address only within the ROI 32. In the area other than the ROI 32, one transmission focus point 34 is set at a predetermined depth. Therefore, in the area other than the ROI 32, the transmission focus points 34 are set as few as possible, and two transmission focus points are set for each beam address in the ROI 32. Therefore, the resolution is improved only for the ROI 32 and the image quality is improved. Can be improved.
[0028]
Incidentally, the horizontal direction in the ultrasonic image 30 represents the beam scanning direction, and the vertical direction represents the depth direction. Each grid of the matrix represents a focus point that can be set.
[0029]
In the example shown in FIG. 3, the ROI 32 is formed with a certain region in an oblique direction. For such an ROI 32, for example, the transmission focus point 34 is set obliquely along the ROI 32. However, since the width in the depth direction of this ROI 32 is narrow, one transmission focus point 34 is set for each beam address. According to such a transmission focus point pattern, the image quality of the ROI 32 can be improved as in the example shown in FIG. Incidentally, the example shown in FIG. 3 has an advantage that the frame rate can be maintained.
[0030]
FIG. 4 shows a setting pattern of other transmission focus points 34 for the ROI 32 shown in FIG. In this example as well, it is possible to improve the image quality of only the ROI 32 while preventing the frame rate from being deteriorated as much as possible.
[0031]
In the example shown in FIG. 5, the ROI 32 is set by a line segment. A focus point 34 is set along the line segment 32. Note that the transmission focus point 34 is fixedly set at a predetermined depth in the beam direction that does not cross the ROI 32.
[0032]
In the example shown in FIG. 6, with respect to the transmission beam passing through the ROI 32 as a line segment, the transmission focus point 34 is set at a predetermined distance from the ROI 32 in the vertical direction. Such a setting has an advantage that the image quality can be improved up to the vicinity of the ROI 32.
[0033]
For example, when the ROI 32 is circular and the position of the transmission focus point 34 is automatically set on the basis of the form of the ROI 32, the methods shown in FIGS. 7 and 8 can be applied. In this example, two transmission focus points 34 are set in the ROI 32 for each beam address.
[0034]
As shown in FIG. 7, when attention is paid to a certain beam address, points A and B crossing the ROI 32 are specified, and a point M is specified as the midpoint thereof. Then, the depth of the transmission focus point 34 for each beam address is determined as the midpoints C and D of the line segment A-M and the line segment B-M. The state after the determination is shown in FIG. Of course, the methods shown in FIGS. 7 and 8 are examples, and various setting methods can be applied according to the form of the ROI 32.
[0035]
Next, the operation of the apparatus shown in FIG. 1 will be described with reference to FIGS.
[0036]
FIG. 9 is a flowchart showing an operation when a transmission focus point is set for each beam address manually.
[0037]
In S101, 1 is substituted for n as an initial value. In S102, the number of transmission focus points and the depth thereof are manually set for the nth beam address. In this case, the input device 16 shown in FIG. 1 is used. In S104, it is determined whether or not n has reached the maximum value, that is, whether or not the transmission focus point has been set up to the last beam address. If not, n is incremented by 1 in S103. The process is repeated.
[0038]
In S105, transmission / reception is executed in accordance with such a transmission focus point setting pattern, and in S106, an ultrasonic image formed by the transmission / reception is displayed on the display device.
[0039]
FIG. 10 is a flowchart showing the operation when the transmission focus point is automatically set.
[0040]
In S201, the lower limit of the frame rate is input by the user. In S202, the focus ratio inside and outside the ROI is input. In S203, the ROI shape is selected by the user. For example, a circular shape, a rectangular shape, or a line segment is prepared as the ROI shape. In S204, the ROI is set on the ultrasonic image using the shape selected as described above.
[0041]
In S205, the transmission focus point is automatically determined. In this case, the ROI set in S204, the number ratio of the focus points set in S202, and the lower limit of the frame rate set in S201 are taken into consideration. That is, in S205, under the condition that the frame rate is not lower than the lower limit of the frame rate, the number of focus points and the depth thereof are automatically calculated based on the shape of the ROI for each beam address with the focus point ratio inside and outside the ROI. Is set. For example, when 2 to 1 is set as the focus point ratio inside and outside the ROI, a transmission focus point setting pattern as shown in FIGS. 2 and 4 is formed. Alternatively, the transmission focus point setting pattern shown in FIG. 8 is formed.
[0042]
In S206, transmission / reception of ultrasonic waves is executed, and in S207, an ultrasonic image formed thereby is displayed as an image.
[0043]
In the embodiment shown in FIG. 10, the ROI shape is selected in S203. However, the ROI shape may be arbitrarily set by the user by a free curve. Further, the shape of the transmission beam may be variably controlled according to the number of transmission focus points. For example, broad focus control may be performed for a beam address for which only one transmission focus point is set, and strong focus may be performed for each focus point for a beam address for which a plurality of transmission focus points are set.
[0044]
In the above embodiment, the transmission focus point setting pattern is determined based on the ROI. However, the scanning range of the transmission beam is divided into a plurality without using such ROI, and the number and depth of the transmission focus points are divided for each division. It may be possible to set the length individually.
[0045]
【The invention's effect】
As described above, according to the present invention, it is possible to improve the image quality of a site of interest while minimizing the decrease in the frame rate. Further, according to the present invention, transmission focus can be controlled for each beam address.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of an ultrasonic diagnostic apparatus according to the present invention.
FIG. 2 is a diagram illustrating a transmission focus point setting pattern.
FIG. 3 is a diagram illustrating a transmission focus point setting pattern.
FIG. 4 is a diagram illustrating a transmission focus point setting pattern.
FIG. 5 is a diagram illustrating a transmission focus point setting pattern.
FIG. 6 is a diagram illustrating a transmission focus point setting pattern.
FIG. 7 is a diagram for explaining a method of automatically setting a transmission focus point.
FIG. 8 is a diagram for explaining a method for automatically setting a transmission focus point;
FIG. 9 is a flowchart showing the operation of the ultrasonic diagnostic apparatus.
FIG. 10 is a flowchart showing the operation of the ultrasonic diagnostic apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Probe, 12 Transmission circuit, 14 Control part, 16 Input device, 18 Reception circuit, 20 Image formation circuit, 22 Display apparatus, 30 Ultrasound image, 32 ROI (region of interest), 34 Transmission focus point.

Claims (4)

Means for setting frame rate conditions;
Means for setting the ratio of the number of transmission focus points inside and outside the region of interest;
A region of interest setting means for setting a region of interest on an ultrasound image;
The frame rate conditions, the ratio of the number of the transmission focusing point, and, with on the basis of the form of the region of interest, Shin setting means sending to set for each beam address of the transmission beam and the number and depth of transmission focus point,
Transmission control means for controlling the formation of the transmission beam according to the setting contents by the transmission setting means;
An ultrasonic diagnostic apparatus comprising: The apparatus of claim 1 .
The ultrasonic diagnostic apparatus, wherein the region of interest setting means is a means for allowing the user to input the region of interest. The apparatus of claim 1.
An ultrasonic diagnostic apparatus, wherein the shape of a transmission beam is controlled according to the number of transmission focus points. The apparatus of claim 3.
For a beam address for which only one transmission focus point is set, the shape of the transmission beam is controlled so as to be broad focus, and for a beam address for which a plurality of transmission focus points are set, the transmission beam is set to be strong focus. An ultrasonic diagnostic apparatus characterized in that the shape of the apparatus is controlled .

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