JP5645628B2 - Ultrasonic diagnostic equipment - Google Patents

Description

  The present invention relates to an ultrasonic diagnostic apparatus and an ultrasonic image generation method, and in particular, an ultrasonic wave used for accurately and accurately displaying a distal end portion of a puncture device such as a puncture needle on an ultrasonic image when performing a puncture operation. The present invention relates to a diagnostic apparatus and an ultrasonic image generation method.

Conventionally, in the medical field, an ultrasonic diagnostic apparatus using an ultrasonic image has been put into practical use. In general, this type of ultrasonic diagnostic apparatus has an ultrasonic probe with a built-in transducer array and an apparatus main body connected to the ultrasonic probe, and ultrasonic waves are directed toward the subject from the ultrasonic probe. , The ultrasonic echo from the subject is received by the ultrasonic probe, and the received signal is electrically processed by the apparatus main body to generate an ultrasonic image.
The ultrasonic diagnostic apparatus is also used when a doctor performs a puncture operation for collecting a tissue sample by puncturing a puncture device, for example, a puncture needle, into a desired site for cell tissue diagnosis.

In puncture, the doctor makes sure that the puncture needle reaches the target object or target site in advance so that a predetermined puncture path (path through which the puncture needle is inserted into the subject) while viewing the ultrasound image. Insert the puncture needle into the street.
When such puncture is performed, the puncture needle is made to reach the treatment target such as the target site or target object, and excess liquid is drained from the treatment target (drainage), or liquid is injected into the treatment target (PEIT ) Etc., it is important that the puncture needle, particularly its tip, can be confirmed reliably, accurately and appropriately on the monitor (ultrasonic image).

Therefore, in the ultrasonic imaging technique disclosed in Patent Document 1, in order to accurately detect the tip position of the puncture needle inserted into the subject, a vibration applying mechanism is attached to the proximal end of the puncture needle, and the puncture needle is mechanically attached. The puncture needle is imaged on the basis of the Doppler signal, and the puncture needle is converted into a Doppler image on the basis of the Doppler signal and displayed on the B-mode image.
In the ultrasonic diagnostic apparatus disclosed in Patent Literature 2, B-mode ultrasonic tomographic image frame data obtained by an ultrasonic probe is accumulated in a memory, and the difference between the previously accumulated frame data and the currently obtained frame data is stored. And a spatial change is obtained as digital data, and this is added to the currently obtained frame data to display a desired puncture needle image on the B-mode ultrasound image. As a result, in Patent Document 2, the vibration applying mechanism and Doppler mode processing necessary for the ultrasonic imaging technique disclosed in Patent Document 1 are unnecessary, and a clear puncture needle image is displayed only from B-mode ultrasonic tomographic image frame data. I can do it.

  Further, in the ultrasonic guided puncture system disclosed in Patent Document 3, a reception signal from an ultrasonic probe from a subject into which a puncture needle is inserted is processed to generate a B-mode image signal, and a B-mode image is generated. Based on the signal, a B-mode ultrasonic tomogram is displayed on the display device, a portion having a higher luminance than the displayed ultrasonic image and the luminance is greatly changed is extracted, and the extracted portion is colored, The colored extraction part is displayed superimposed on the latest ultrasonic tomographic image. As a result, Patent Document 3 states that an ultrasonic guided puncture system that can perform treatment and examination reliably and satisfactorily without losing sight of the needle tip of a puncture needle once inserted into a patient can be provided at low cost.

Patent No. 4030644 JP 2001-269339 A JP 2000-107178 A

By the way, the technique disclosed in Patent Document 1 requires a special mechanism for mechanically vibrating the puncture needle, which increases the size of the apparatus and increases the cost. When performing, there exists a problem that the Doppler signal from a blood vessel and the Doppler signal from a puncture needle cannot be isolate | separated.
Here, in the puncture technique, the thinner the puncture needle is, the less burden on the patient and the less invasiveness, so the puncture needle as thin as possible is selected according to the risk. However, as the puncture needle becomes thinner, the drawing output on the ultrasonic image also decreases, and the puncture needle is drawn intermittently, and there is a problem that the position or shape of the puncture needle cannot be clearly displayed.

The technique disclosed in Patent Document 2 can solve the above-described problems of the technique disclosed in Patent Document 1, and can display a clear puncture needle image only from B-mode ultrasonic tomographic image frame data.
However, as described above, when a thin puncture needle is used, the B-mode ultrasonic tomographic image frame data itself is data that is difficult to clearly display the position or shape of the puncture needle. There is a problem that only accurate spatial change data due to needle insertion cannot be obtained, and an accurate puncture needle image cannot be obtained.
Furthermore, when the puncture needle is inserted into a subject such as a patient, not only the case where only the puncture needle changes spatially, but the subject moves according to the movement of the patient or the like, causing a spatial change, Since the sample itself may change in accordance with the insertion of the puncture needle to cause a spatial change, in this case, the difference data in Patent Document 2 includes not only the insertion of the puncture needle but also the movement of the subject. And spatial change data due to changes in the subject itself are included, and there is a problem that it is not possible to separate only the spatial change data due to insertion of the puncture needle and not only the puncture needle image. In addition, since the B-mode ultrasound tomographic image frame data itself includes noise, the difference data also includes data due to the noise, and the process for separating the data due to the noise is not performed. As long as there is a problem that only obtaining a puncture needle image cannot be separated.

Further, in the technique disclosed in Patent Document 3, as in the technique disclosed in Patent Document 2, the latest image data is compared with the image data one screen before this, and the change in the high-luminance portion of the ultrasonic tomographic image is changed. The extracted part is colored and displayed as the needle tip of the puncture needle, but the part with the change in the high-intensity part is not only the change in the high-intensity part caused by the insertion of the puncture needle. It may exist as a change in the specimen, a change in the subject itself, or a change in the high luminance part due to noise. In this case, only the movement of the needle tip of the puncture needle due to insertion cannot be separated, and the needle of the puncture needle There is a problem that only the front part cannot be separated.
In the technique disclosed in Patent Document 3, the high-intensity part of the ultrasonic tomographic image is a puncture needle, but it is difficult to determine what high-intensity part corresponds to the puncture needle. As described above, when a thin puncture needle is used, it is not possible to extract only a high-intensity portion corresponding to the puncture needle in an ultrasonic tomographic image in which it is difficult to clearly display the position or shape of the puncture needle. There is also a problem.

  An object of the present invention is to eliminate the above-mentioned problems of the prior art and perform puncture without using a special mechanism or Doppler mode processing for mechanically vibrating a puncture device such as a puncture needle when performing puncture. An object of the present invention is to provide an ultrasonic diagnostic apparatus and an ultrasonic image generation method capable of accurately, accurately, and easily displaying the tip of an instrument on an ultrasonic image.

  In order to achieve the above object, an ultrasonic diagnostic apparatus of the present invention transmits an ultrasonic wave to a subject into which a puncture device is inserted and receives a reflected wave of the ultrasonic wave from the subject and the puncture device. An ultrasonic transmission / reception unit that generates an echo signal of a time-series frame based on the received reflected wave; and an ultrasonic that generates an ultrasonic image of the subject based on the echo signal generated by the ultrasonic transmission / reception unit A sound wave image generating means; an image display means for displaying the ultrasonic image generated by the ultrasonic image generating means; and a difference for generating a differential echo signal between time series frames from the echo signals of a plurality of time series frames. Based on the echo signal generating means and the differential echo signal generated by the differential echo signal generating means, tip detection processing is performed, and one or more tip candidates including the tip of the puncture device are obtained. A tip candidate detection unit that outputs and a tip that performs display enhancement processing on the tip candidate of the puncture device detected by the tip candidate detection unit, and generates a tip image in which the tip candidate of the puncture device is displayed and emphasized Candidate processing means, wherein the image display means converts the tip image of the puncture device subjected to display enhancement processing by the tip candidate processing means to the ultrasound image generated by the ultrasound image generation means. It is characterized by being displayed in an overlapping manner.

Here, it is preferable that the tip candidate detection unit detects the tip candidate of the puncture device based on a luminance difference of the differential echo signal generated by the differential echo signal generation unit as the tip detection processing. .
Further, it is preferable that the tip candidate processing means performs display enhancement processing on the tip candidate of the puncture device detected by the tip candidate detecting means according to the sign of the luminance difference of the differential echo signal.
Further, the tip candidate processing unit generates a color tip image by coloring the tip candidate of the puncture device detected by the tip candidate detecting unit as the display enhancement processing, or brightness of the tip candidate It is preferable to increase the brightness to generate a high-luminance tip image, or to color the tip candidate and increase the brightness to generate a high-luminance color tip image.
The tip candidate detecting means further determines the sign of the luminance difference of the differential echo signal, and the tip candidate processing means determines whether the luminance difference of the differential echo signal determined by the tip candidate detecting means is positive or negative. Accordingly, it is preferable to change the hue and brightness for display enhancement processing of the tip candidate of the puncture device detected by the tip candidate detecting means.

The differential echo signal generation means further generates a differential image based on the generated differential echo signal, and the tip candidate detection means is the differential image generated by the differential echo signal generation means. Furthermore, it is preferable that the tip detection process is performed to detect the tip candidate of the puncture device.
In addition, the tip candidate detection unit performs a process of extracting a portion having a predetermined luminance difference or more on the difference image generated by the difference echo signal generation unit as the tip detection process, and the tip candidate of the puncture device Is preferably detected.
In addition, the tip candidate detecting means may extract a portion of the difference image that is greater than or equal to a predetermined luminance difference from the difference image generated by the difference echo signal generating means as the tip detection process. It is preferable to perform look-up table processing using a look-up table for performing adjustment processing and detect the tip candidate of the puncture device.
The look-up table used in the look-up table processing by the tip candidate detecting means is preferably adjusted according to at least one of the ultrasonic image and the difference image.

Further, the tip candidate detecting means detects the tip candidate of the puncture device based on the difference in luminance of the difference image and the size and density of the area detected by the luminance difference as the tip detection process. It is preferable.
Further, it is preferable that the tip candidate detecting unit performs tip enhancement filter processing on the difference image as the tip detection processing to detect the tip candidate of the puncture device.
Further, the tip candidate detecting means performs a median filtering process on the difference image as the tip detecting process, or a filter process for obtaining a luminance sum of pixels near a predetermined point and emphasizing only a portion where the luminance sum is large. Preferably, the tip candidate of the puncture device is detected.
Further, the tip candidate detecting means searches for a region near the tip candidate of the puncture device detected at a time earlier than the frame displayed on the image display means, and from the difference image based on the display frame, It is preferable to detect the tip candidate of the puncture device.
Further, the tip candidate detecting means searches for a neighborhood region of a straight line connecting the tip candidates of the puncture device detected at the past two times from the frame displayed on the image display means, and based on the display frame It is preferable to detect the tip candidate of the puncture device from the difference image.

Moreover, it is preferable that the said difference echo signal production | generation means is equipped with the function which can adjust the time difference between the said time-sequential frames which produce the said difference image.
Further, it is preferable that the differential echo signal generation means uses a plurality of frames two or more frames before as the past frame for generating the differential image.
In addition, the differential echo signal generation means, as pre-processing, signal processing for reducing speckle patterns, signal processing for blurring in the direction of the puncture device, and / or a signal for connecting the puncture device to the time-series echo signal It is preferable to generate the differential echo signal after performing the processing.
Further, it is preferable that the image display means also displays an image of the tip candidate of the puncture device detected at a past time, and displays a puncture locus of the puncture device.
Further, the tip candidate processing means performs display enhancement processing on the tip candidate of the puncture device detected by the tip candidate point detection means, and displays a tip emphasized image obtained by performing display enhancement processing on the tip candidate of the puncture device. And the image display means generates the tip-enhanced image in which the tip candidate of the puncture device generated by the tip candidate processing means is subjected to display enhancement processing, and the ultrasound generated by the ultrasound image generation means. It is preferable to display it superimposed on the image.
Further, the tip image on which the tip candidate of the puncture device generated by the tip candidate processing unit is subjected to display emphasis processing is synthesized so as to be superimposed on the ultrasound image generated by the ultrasound image generating unit. It is preferable that the image display unit display a composite image synthesized by the image composition unit.

According to the present invention, when performing a puncture, the tip of the puncture device can be accurately converted into an ultrasonic image without using a special mechanism for mechanically vibrating the puncture device such as a puncture needle or Doppler mode processing. And can be displayed accurately and easily.
As a result, according to the present invention, even when a puncture device such as a thin puncture needle is used, the distal end portion of the puncture device can surely reach the target site.

1 is a block diagram schematically showing a configuration of an embodiment of an ultrasonic diagnostic apparatus of the present invention. FIG. 2 is a block diagram showing details of an embodiment of a puncture needle tip detection unit of a composite image generation unit of the ultrasonic diagnostic apparatus shown in FIG. 1. It is a figure showing an example of the difference image obtained by the difference image generation part of the synthetic | combination image generation part of the ultrasonic diagnosing device shown in FIG. It is a figure showing an example of the ultrasonic image which displayed the insertion locus | trajectory of a puncture needle. (A) And (B) is a figure showing an example of the tip emphasis filter applied to the difference image and difference image which are respectively used by the puncture needle tip detection part shown in FIG. It is a block diagram which shows one Example of the time-sequential frame difference image generation part of the synthesized image generation part shown in FIG. It is a functional block diagram which shows one Example of the puncture needle process part of the time series frame difference image generation part shown in FIG. (A), (B), and (C) are one-frame ultrasonic images processed by the filter application processing unit of the puncture needle processing unit shown in FIG. 7, the applied puncture needle enhancement filter, and the processed puncture needle It is a figure showing an example of an emphasis ultrasonic picture. It is a functional block diagram which shows the other Example of the puncture needle process part of the time series frame difference image generation part shown in FIG. FIG. 10 is a functional block diagram showing a detailed configuration of a puncture needle region specifying unit and a puncture needle tip position specifying unit of the puncture needle processing unit shown in FIG. 9. (A) is a B-mode image according to the present invention, (B) is an edge image obtained by performing threshold processing on the B-mode image shown in (A), and (C) is a Hough transform into an edge image shown in (B). (D) is a diagram showing an example of an edge image in which a puncture needle presence region is superimposed and displayed on the edge image shown in (C). (A) is a schematic diagram showing a tip position specifying method in the puncture needle presence region shown in FIG. 11 (D), and (B) is a straight line connecting the tip position of the puncture needle and the start point of the puncture needle according to (A). It is a schematic diagram showing. It is a flowchart which shows an example of the principal part of the ultrasonic image generation method of this invention. (A) and (B) are ultrasonic images of two time-series frames, (C) is a difference image of ultrasonic images shown in (A) and (B), and (D) is in (C). (E) is a figure showing an example of the look-up table process image of the difference image shown to (C). It is a figure showing an example of the Gaussian filter used as a base which determines the filter coefficient of the tip emphasis filter shown in Drawing 14 (D). It is a figure showing distribution of the tip candidate point of the puncture needle after the binarization processing of the difference image shown in Drawing 14 (C). It is a flowchart which shows another example of the principal part of the ultrasonic image generation method of this invention. It is a block diagram which shows typically the structure of other embodiment of the diagnostic apparatus main body of the ultrasonic diagnosing device of this invention.

  An ultrasonic diagnostic apparatus and an ultrasonic image generation method according to the present invention will be described below in detail based on preferred embodiments shown in the accompanying drawings.

FIG. 1 is a block diagram schematically showing a configuration of an embodiment of an ultrasonic diagnostic apparatus of the present invention that implements the ultrasonic image generation method of the present invention. FIG. 2 is an ultrasonic diagnostic apparatus shown in FIG. It is a block diagram which shows the detail of one Example of the puncture needle front-end | tip detection part of the synthetic | combination image generation part.
As shown in FIG. 1, the ultrasonic diagnostic apparatus 10 of the present invention irradiates (transmits) ultrasonic waves to a subject, particularly a subject into which a puncture device such as a puncture needle is inserted. An apparatus for generating and displaying an ultrasonic image from an echo signal obtained by receiving an ultrasonic wave (echo) reflected from the instrument, in particular, an ultrasonic image obtained by synthesizing the tip of the puncture instrument, and providing for ultrasonic image diagnosis And it has the ultrasonic probe 12 and the diagnostic apparatus main body 14 to which this ultrasonic probe 12 is connected. Hereinafter, a puncture needle will be described as a representative example of the puncture device, but the present invention is not limited to this.

The ultrasonic probe 12 is also called a probe, is used by being pressed against a subject, transmits / receives ultrasonic waves, and outputs a received echo signal to the diagnostic apparatus main body 14. And a puncture adapter 20.
The probe main body 16 is a converter that converts an electrical signal into an ultrasonic wave and irradiates (transmits), and receives an ultrasonic wave reflected from a subject and converts it into an electrical signal (echo signal). In addition, it is a known ultrasonic probe, and may be any type of ultrasonic probe such as a linear scan method, a convex scan method, and a sector scan method.
The detailed configuration of the probe body 16 will be described later.

The probe body 16 has an ultrasonic transmission / reception surface (not shown) for transmitting and receiving ultrasonic waves, and a communication cable 18 is connected to the opposite side of the ultrasonic transmission / reception surface, and one of the ultrasonic transmission / reception surfaces. A puncture adapter 20 is disposed on the side surface of the.
The communication cable 18 is for transmitting an echo signal from the probe main body 16 to the diagnostic apparatus main body 14.

The puncture adapter 20 serves as a guide for inserting a puncture device such as a puncture needle into a subject when performing puncture using the ultrasonic diagnostic apparatus 10. The puncture adapter 20 is formed with a guide groove for allowing the puncture needle to be inserted into the subject at a certain angle, and the puncture needle is inserted along the guide groove so that the subject is fixed to the subject. It is inserted at an angle of. That is, the angle at which the puncture needle is inserted into the subject (hereinafter referred to as the insertion angle) is determined by the angle of the guide groove of the puncture adapter 20 with respect to the subject. The guide groove of the puncture adapter 20 can change the angle with respect to the subject, and can adjust the insertion angle.
The puncture adapter 20 is preferably not only physically connected to the probe body 16 but also electrically connected. In this case, the puncture adapter 20 can hold information regarding the insertion angle. When such a puncture adapter 20 is physically connected to the probe body 16, the puncture adapter 20 is also electrically connected, so that a signal representing the insertion angle can be output to the probe body 16. Further, the puncture adapter 20 can output a signal representing the current insertion angle to the probe body 16 every time the angle of the groove with respect to the subject is changed.

As shown in FIG. 1, the probe main body 16 includes a plurality of ultrasonic transducers 34, a plurality of reception signal processing units 36, a transmission drive unit 38, a transmission control unit 40, a reception control unit 42, and a probe control unit. 44.
The plurality of ultrasonic transducers 34 constitute a one-dimensional or two-dimensional transducer array, and a plurality of reception signal processing units 36 are connected to each of the plurality of transducers 34. Further, a transmission control unit 40 is connected to the plurality of transducers 34 via the transmission drive unit 38, a reception control unit 42 is connected to the plurality of reception signal processing units 36, and a probe is connected to the transmission control unit 40 and the reception control unit 42. A control unit 44 is connected.
The reception signal processing unit 36 is connected to the data storage unit 46 of the diagnostic apparatus main body 14, and the probe control unit 44 is connected to the main body control unit 54 via a communication cable.

The plurality of transducers 34 transmit ultrasonic waves to the subject according to the drive signals supplied from the transmission drive unit 38, respectively, receive ultrasonic echoes from the subject, and output reception signals. Each transducer 34 is a vibration in which electrodes are formed on both ends of a piezoelectric body made of, for example, a piezoelectric ceramic represented by PZT (lead zirconate titanate) or a polymer piezoelectric element represented by PVDF (polyvinylidene fluoride). Consists of children.
When a pulse or continuous wave voltage is applied to the electrodes of such a vibrator, the piezoelectric body of the vibrator expands and contracts, and pulse or continuous wave ultrasonic waves are generated from the respective vibrators. An ultrasonic beam is formed by combining the above. In addition, each transducer generates an electric signal by expanding and contracting by receiving propagating ultrasonic waves, and these electric signals are output as ultrasonic reception signals.

  The transmission drive unit 38 includes, for example, a plurality of pulsers, and ultrasonic waves transmitted from the plurality of transducers 34 pass through the tissue area in the subject based on the transmission delay pattern selected by the transmission control unit 40. The delay amount of each drive signal is adjusted so as to form a wide ultrasonic beam to be covered and supplied to the plurality of transducers 34.

The reception signal processing unit 36 of each channel performs amplification and digital (A / D) conversion processing on the reception signal output from the corresponding transducer 34 under the control of the reception control unit 42, and further performs quadrature detection processing. Alternatively, a complex baseband signal is generated by performing orthogonal sampling processing, and sample data including information on the area of the tissue is generated by sampling the complex baseband signal. The reception signal processing unit 36 may generate sample data by performing data compression processing for high-efficiency encoding on data obtained by sampling the complex baseband signal.
In this specification, a signal is also used as a thing that mainly represents a signal level (signal value) in hardware, and data is processed in software and represents a magnitude (data value). Also used as a thing.
The probe control unit 44 controls each part of the probe main body 16 based on various control signals transmitted from the diagnostic apparatus main body 14.

On the other hand, as shown in FIG. 1, the diagnostic apparatus main body 14 includes a data storage unit 46, a composite image generation unit 48, a display control unit 50, a display unit 52, a main body control unit 54, an operation unit 56, And a storage unit 58.
In the diagnostic device main body 14, a composite image generation unit 48 is connected to the data storage unit 46, and a plurality of reception signal processing units 36 of the probe main body 16 are connected. A display unit 52 is connected to the composite image generation unit 48 via a display control unit 50. A main body control unit 54 is connected to the composite image generation unit 48 and the display control unit 50. Furthermore, an operation unit 56 and a storage unit 58 are connected to the main body control unit 54.

The data storage unit 46 includes a memory, a hard disk, or the like, and stores at least one frame of sample data transmitted in time series from the reception signal processing unit 36 of the ultrasonic probe 12 via the communication cable 18.
The composite image generation unit 48 performs reception focus processing on the sample data for each frame read from the data storage unit 46 to perform image data (B-mode image signal) of an ultrasonic image that is a B-mode image of one frame, particularly Image data (image signal) of an ultrasound diagnostic image such as a synthesized ultrasound image in which a tip image with the tip of the puncture needle displayed and emphasized is synthesized is generated.
Note that in this specification, an image can be regarded as an aggregate of image data or image signals of each pixel, and therefore an aggregate of image data or image signals representing an image is also simply referred to as an image.
Details of the composite image generation unit 48 will be described later.

The display control unit 50 displays, on the display unit 52, an ultrasound image, particularly an ultrasound diagnostic image in which the tip of the puncture needle is displayed and emphasized, based on the image signal of the ultrasound image generated by the composite image generation unit 48. It has a DSC (digital scan converter). In this DSC, the display control unit 50 converts (raster conversion) an image signal of an ultrasonic image into an image signal in accordance with a normal television signal scanning method, and performs necessary image processing such as gradation processing. Then, it is converted into a display image signal to be displayed on the display unit 52.
The display unit 52 is for displaying an ultrasonic image based on the display image signal converted by the display control unit 50 and includes, for example, a display device such as an LCD and a monitor. Under the control, the tip portion of the puncture needle subjected to the display enhancement process is displayed so as to be superimposed on the ultrasonic image.

The operation unit 56 is used for an operator to perform an input operation for operating the ultrasonic diagnostic apparatus 10, and is a part for setting an imaging menu, imaging conditions, and the like and instructing imaging of a subject. The operation unit 56 is provided with input means such as an input key for setting a shooting menu, shooting conditions, and the like, a dial button, a trackball, and a touch panel.
The operation unit 56 also has a function for inputting an instruction to input / set the position of the target (target site) and set the insertion angle. Furthermore, the operation unit 56 may have a function of inputting an instruction for the insertion position of the puncture needle. The operation unit 56 supplies the input target position setting instruction, insertion angle setting instruction, and insertion position instruction to the main body control unit 54.

The main body control unit 54 controls each part in the diagnostic apparatus main body 14 including the composite image generation unit 48 and the display control unit 50. The main body control unit 54 is connected to the probe control unit 44 of the probe main body 16 via the communication cable 18 and supplies a control signal for controlling the operation of the probe main body 16 to the probe control unit 44.
The storage unit 58 is configured by a memory, a hard disk, or the like, and stores an operation program for operating each unit in the diagnostic apparatus main body 14 including the composite image generation unit 48 and the display control unit 50 controlled by the main body control unit 54. To do. The main body control unit 54 reads out an operation program for operating each unit in the diagnostic device main body 14 from the storage unit 58 as necessary, and operates each unit in the diagnostic device main body 14 according to the read operation program.

The composite image generation unit 48 includes an image generation unit 64, a time-series frame image storage unit (hereinafter also simply referred to as an image storage unit) 66, and a time-series frame difference image generation unit (hereinafter also simply referred to as a difference image generation unit). 68, a puncture needle tip detection unit (hereinafter also simply referred to as a tip detection unit) 70, and an image composition unit 72.
The image generation unit 64 is for generating a B-mode image signal that is tomographic image information from the sample data for each frame read from the data storage unit 46, and includes a phasing addition unit 60 and an image processing unit 62. Have.
The phasing / adding unit 60 selects one reception delay pattern from a plurality of reception delay patterns stored in advance according to the reception direction set in the main body control unit 54, and sets the selected reception delay pattern. On the basis of a plurality of complex baseband signals represented by the sample data for each frame read from the data storage unit 46, and by adding the respective phases after adjusting the phases (phased addition), Receive focus processing (beam forming) is performed. The phasing addition unit 60 generates a baseband signal (sound ray signal) in which the focus of the ultrasonic echo is narrowed for each frame, that is, a so-called echo signal for each frame, by this reception focus processing.

The image processing unit 62 generates a B-mode image signal, which is tomographic image information related to the tissue in the subject, based on the echo signal (sound ray signal) for each frame generated by the phasing addition unit 60. The image processing unit 62 includes a high-frequency amplifier, a logarithmic amplifier, a luminance converter, and the like including a band-pass filter and an STC (self-correction timing control) unit.
Here, the band pass filter changes the pass band according to the propagation time of the ultrasonic echo to improve the S / N ratio. The STC unit of the high-frequency amplifier controls the gain to be amplified according to the propagation time, and corrects the attenuation due to the distance according to the depth of the reflection position of the ultrasonic wave with respect to the echo signal (sound ray signal). The logarithmic amplifier compresses and amplifies the fluctuation range of the amplitude of the echo signal that fluctuates over a wide range. The luminance converter generates a B-mode image signal for each frame, which is tomographic image information, by converting the amplitude into luminance and displaying the echo signal with one bright line subjected to luminance modulation.

The time-series frame image storage unit 66 is a memory that stores a B-mode image signal representing a plurality of frames of images as a time-series frame image in a time-series manner. Consists of.
The time-series frame difference image generation unit 68 obtains a difference between two time-series frame images (B-mode image signals) stored in the image storage unit 66 and generates a difference image (difference image signal).
A preferable detailed configuration of the difference image generation unit 68 will be described later.

The puncture needle tip detection unit 70 is the most characteristic part of the present invention, and performs tip detection processing from the difference image generated by the difference image generation unit 68. For example, the luminance difference of each pixel of the difference image is used. One or more tip candidates including the tip portion of the puncture needle are detected, display enhancement processing is performed on the detected tip candidate, and a tip image subjected to display enhancement processing is generated.
As shown in FIG. 3, when the puncture needle 102 to be inserted is generated in the difference image 100, the tip detection unit 70 obtains the moved portion of the tip 104 of the puncture needle 102 as a difference. Only the most important tip 104 can be detected by puncturing. It is most preferable that the tip detection unit 70 detects only one tip candidate 106 corresponding to the tip 104 of the puncture needle 102. Usually, however, the difference image 100 shows movement or noise of the puncture target other than the puncture needle 102. As described above, a plurality of tip candidates 106 are detected, and it is not always possible to detect only one tip candidate corresponding to the tip portion 104 of the puncture needle 102.

Therefore, in the present invention, when the number of tip candidates detected by the tip detection unit 70 is one or a predetermined number, for example, six or less, for example, coloring is performed on the tip candidates as display enhancement processing. It is preferred to process and / or increase brightness to generate a color and / or high brightness tip image. In addition, when there are many tip candidates detected by the tip detector 70, for example, when there are more than six, it is preferable to narrow down to one or more tip candidates except for tip candidates with low accuracy. It is most preferable to narrow down to one tip candidate, and it is preferable to similarly perform display enhancement processing on the narrowed tip candidates to generate a color and / or high brightness tip image.
The detailed configuration of the tip detection unit 70 will be described later.

The image synthesis unit 72 synthesizes the tip image (puncture needle tip portion emphasis image) generated by the tip detection unit 70 with the ultrasound image that is the B-mode image generated by the image processing unit 62 and combines the ultrasound image. Is generated.
Thus, the synthesized ultrasonic image (image signal) generated by the image synthesis unit 72 is transmitted to the display control unit 50.

In the diagnostic apparatus main body 14 of the illustrated ultrasonic diagnostic apparatus 10, the display control unit 50 is provided with a DSC, and the combined ultrasonic image (image signal) combined by the image combining unit 72 is displayed on the display unit 52. However, the present invention is not limited to this, and the image synthesis unit 72 is provided with a DSC, and in this DSC, a synthesized ultrasound image synthesized by the image synthesis unit 72 ( Even if a B-mode image signal for monitor display is generated by converting the image signal) into an image signal in accordance with a normal television signal scanning method (raster conversion) and performing necessary image processing such as gradation processing. good.
In addition, the image processing unit 62 is provided with a DSC, and in this DSC, an echo signal (sound ray signal) corrected by the STC unit and a luminance-modulated B-mode image signal are scanned with a normal television signal. A monitor display B-mode image signal may be generated by performing conversion (raster conversion) to an image signal conforming to the method and performing necessary image processing such as gradation processing. In this case, if the display image signal is used to detect the tip of the puncture needle, the display controller 50 and the image compositing unit 72 may not be provided with a DSC.

Next, a detailed configuration of the puncture needle tip detection unit 70, which is the most characteristic feature of the present invention, will be described.
As shown in FIG. 2, the puncture needle tip detection unit 70 includes a tip candidate detection unit 74, a tip candidate processing unit 76, a tip candidate storage unit 78, a puncture needle information and condition storage unit (hereinafter simply referred to as an information storage unit). 80).
The tip candidate detection unit 74 performs tip detection processing on the difference image generated by the difference image generation unit 68 and detects one or more tip candidates including the tip portion of the puncture needle. An extraction processing unit (hereinafter also referred to as an extraction processing unit) 82 and a tip candidate specifying processing unit (hereinafter also referred to as a specific processing unit) 84 are included.

As one of the tip detection processes, the candidate point extraction processing unit 82 first has a point having a luminance difference value of a predetermined condition based on the luminance difference or luminance value of the difference image, for example, binarization processing, filtering processing, Perform LUT (look-up table) processing for gradation processing, etc., and perform areas or portions (a set of pixels) that are greater than or less than a predetermined luminance difference or greater than or less than a predetermined luminance value with respect to the luminance of peripheral portions. Is extracted as a tip candidate point of the puncture needle.
In the extraction processing unit 82, it is preferable to select and extract the tip candidates of the puncture needle based on the tip candidate points and the density and size of the regions detected according to the luminance difference in the difference image. Specifically, a median filtering process, a luminance sum of pixels near a predetermined point is obtained, a portion where the luminance sum is large, or a portion exceeding a predetermined threshold may be extracted as a tip candidate point, good.

Further, the extraction processing unit 82 refers to the position of the tip candidate detected in the past and is stored in the tip candidate storage unit 78 to set the tip candidate extraction region in advance, and then performs the LUT process. Is preferred. In particular, the extraction processing unit 82 extracts a region having a certain luminance difference or more as a puncture needle tip candidate point from a region in the vicinity of a straight line connecting two or more puncture needle tip candidates detected in the past. Alternatively, it may be detected as a tip candidate.
By doing so, it is possible to search for a tip candidate point and a tip candidate in consideration of the movement and direction of the puncture needle, so that more accurate tip candidate point extraction processing and tip candidate detection processing can be performed.

When a plurality of tip candidate points of the puncture needle are extracted by the extraction processing unit 82, the tip candidate specifying processing unit 84 performs processing for removing tip candidate points with low accuracy as one of tip detection processing, for example, By specifying only the center point of the highly correlated area as the tip candidate, the number of tip candidate points is narrowed down to a predetermined number, for example, one to six, most preferably one, and narrowed tip candidates A point is identified as a tip candidate to be detected.
As a process of removing the tip candidate points having such low accuracy, when a plurality of tip candidate points remain after the LUT processing by the extraction processing unit 82, the specific processing unit 84 detects a plurality of tips detected in the past. It is preferable to narrow the tip candidate point from the point where the distance from the candidate position point is the minimum. That is, a plurality of past puncture needle tip candidate detection results are stored in the tip candidate storage unit 78. For example, as shown in FIG. 4, five frames of detection result points (tip candidates) and the current detection are detected. Among the candidate tip candidates, the candidate point with the smallest distance between the two points may be the current detection result. As shown in FIG. 4, such a method is effective when narrowing down the tip candidate points by the specific processing unit 84 when a plurality of tip candidate points are extracted in the simple tip candidate point extraction by the extraction processing unit 82. It is.

If the tip candidate points of the puncture needle extracted by the extraction processing unit 82 are a predetermined number, for example, 1 or more and 6 or less as described above, the specific processing unit 84 uses the candidate points as they are. It may be specified as a tip candidate of a puncture needle to be detected, or may be narrowed down to a smaller number, preferably one.
When the number of tip candidate points extracted by the extraction processing unit 82 is always smaller than the predetermined number of tip candidates to be detected by the tip candidate detecting unit 74, for example, the number is one or more and six or less. In this case, the specific processing unit 84 may not be provided.

As a result of the LUT processing by the extraction processing unit 82, when no tip candidate points of the puncture needle have been extracted, the tip candidates stored in the tip candidate storage unit 78 and detected in the previous time or the past are stored. May be extracted as a tip candidate point to be detected this time, or may be detected as a tip candidate, or a new tip candidate point or tip candidate may be estimated from tip candidates detected in the past. The tip candidate points extracted or estimated by the extraction processing unit 82 are specified by the specification processing unit 84 as tip candidates to be detected this time. In addition, the specification processing unit 84 may specify the tip candidates themselves detected in the past or the estimated tip candidates directly as tip candidates to be detected this time.
In such a case, it is assumed that there has been no movement due to the insertion of the puncture needle, so it can be seen that the tip candidates detected in the previous time or in the past may be used.

Further, even when the tip candidate detection unit 74 cannot detect an optimum tip candidate in the current frame, the tip candidate detection unit 74 displays the past detection result stored in the tip candidate storage unit 78 on the display unit 52. May be. For example, if there are a plurality of past detection results, the straight line formula and the puncture speed of the puncture needle are also obtained, so the point estimated from these two may be displayed as the tip candidate. Alternatively, the point when the tip candidate detection unit 74 succeeds in the last detection may be continuously displayed as the tip candidate.
In this way, the tip candidate detection unit 74 detects a predetermined number, for example, 1 to 6 tip candidates. In the present invention, the number of tip candidates detected by the tip candidate detecting unit 74 is preferably six. If the inventor detects at least six tip candidates, the number of tip candidates is six. This is because it is confirmed that there is a high probability that the tip of the puncture needle is included in the puncture needle.

In the above-described example, the extraction processing unit 82 and the specific processing unit 84 perform LUT processing such as binarization processing, filter processing, and gradation processing as leading edge detection processing. Without limitation, in order to set the number of tip candidate points of the puncture needle extracted by the extraction processing unit 82 to the above-mentioned predetermined number, LUT processing such as gradation processing is performed after binarization processing, and the luminance difference is larger A predetermined number may be selected.
Further, the LUT used for the LUT processing of the extraction processing unit 82 or the specific processing unit 84 is at least one of an ultrasonic image (B mode image) generated by the image generation unit 64 and a difference image generated by the difference image generation unit 68. You may adjust according to. That is, in the LUT process, it is preferable to use a tip emphasis filter having a size including a puncture needle tip portion weighted in the insertion direction of the puncture needle. Since such a tip enhancement filter is applied to the difference image, it can be said to be a filter that detects the movement of the puncture needle.
As such a tip emphasis filter, the filter shape is a stepped shape, and the filter is in a form in which pixels in the direction in which the puncture needle is inserted is used for weighted addition, or the filter shape is rectangular and the puncture needle is inserted. It is possible to use a filter that performs weighted addition in which the filter coefficient of a pixel in a certain direction is large.

Here, FIG. 5A and FIG. 5B show an example of the tip emphasis filter used in the LUT process applied to the difference image including the image of the tip of the puncture needle and the difference image in the tip detection unit 70.
The tip emphasis filter having a size of 81 × 81 shown in FIG. 5B is weighted in the insertion direction of the puncture needle in the difference image shown in FIG. 5A and includes the tip of the puncture needle. This is a rectangular filter having a (size) and performing weighted addition with a large filter coefficient of a pixel in the insertion direction.
Such a tip enhancement filter is an odd-numbered pixel both vertically and horizontally so that the target pixel comes to the center, and the filter coefficient of each pixel can be determined by applying a Gaussian function expressed by the following equation (1). . That is, the tip enhancement filter shown in FIG. 5B is a filter generated by applying the Gaussian function shown in the following equation (1).

Here, f (x, y) is a filter coefficient, μx and μy are averages in the x and y directions, σ _x and σ _y are x and y direction variances, ρ is a correlation value, and μx = μy = 0, σ _x ² = σ _y ² = 40, ρ = 0.9. FIG. 5B shows the magnitude of the filter coefficient of the filter by the density of the density. In this way, it is possible to create a filter coefficient that increases the filter coefficient for a pixel in the direction in which the puncture needle is inserted.
In FIG. 5B, the closer to the center, the larger the filter coefficient, and the same filter coefficient on a concentric ellipse centered on the center pixel. In FIG. 5B, for ease of understanding, concentric ellipses are drawn with a boundary, but it goes without saying that the boundary as shown does not exist. The longitudinal direction of the ellipse is the same direction as the insertion direction of the puncture needle. That is, by increasing the filter coefficient in the insertion direction of the puncture needle, weighted addition is performed with the filter coefficient of a pixel at a position where the possibility of the presence of the puncture needle is high.

The tip emphasis filter having the aspect ratio corresponding to the insertion angle thus created is stored in the information storage unit 80.
In the present invention, the tip enhancement filter to be used is determined according to the insertion angle, stored in the information storage unit 80, and the tip candidate detection unit 74 stores the difference image in the information storage unit 80. By performing the tip emphasis process that performs weighted addition with surrounding pixels using the tip emphasis filter that has been used, a tip candidate that is a highly accurate candidate for the tip of the puncture needle can be detected.

When obtaining the density and size of the region detected in the difference image, a filter having a size including the tip of the puncture needle as shown in FIG. 5B is used as follows. Can be created.
The size including the tip of the puncture needle of the filter is plural, for example, “large, medium, small” according to the thickness of the puncture needle, and “10 °, 30 °” according to the insertion angle of the puncture needle. A plurality of types may be prepared between 10 ° and 60 ° such as “60 °”. Also, the size of the puncture needle (G), puncture purpose (FNA (Fine Needle Aspiration Cytology), CNB (Core Needle Biopsy), RFA (Radiofrequency Ablation), etc.), The size may be determined using puncture information such as the insertion angle.
Further, as described above, a Gaussian function or the like may be used for filter weighting. In this case, the weight ratio may be prepared as a parameter that allows the user to change the average, variance, correlation, and the like.

Further, the change of the filter size and the weight of the weighting filter may be selected by the user in advance on the setting screen, or a function is assigned to a function key or the like, and can be changed during scanning of the ultrasonic probe 12. You may do it.
As the tip emphasis filter used in the present invention, for example, described in 2010-216512 Patent Application No. a copending application of the present applicant "ultrasonic image generating apparatus and an ultrasonic image generating method" Various puncture device emphasizing filters used for the puncture device emphasis process performed can be mentioned.

In addition, when extracting the tip candidate point of the puncture needle and detecting the tip candidate by performing the LUT processing in the extraction processing unit 82 and the specific processing unit 84, the size to which the tip enhancement filter of the puncture needle is applied from the difference image The tip candidate point periphery may be colored. By doing so, it is possible to detect a tip candidate point in the colored region as a tip candidate, and it is possible to increase the accuracy and probability that the detected tip candidate is the tip portion of the puncture needle.
Further, the extraction processing unit 82 and / or the specific processing unit 84 of the tip candidate detecting unit 74 may detect the tip candidate of the puncture needle detected at a past time from the display frame in the difference image based on the frame displayed on the display unit 52. , Preferably a region near the straight line connecting the tip candidates of the puncture needle detected at the past two times from the display frame, and detecting the tip candidate of the puncture needle from the difference image based on the display frame It is also preferable. By doing so, it is possible to detect a tip candidate having a high probability of being the tip of the puncture needle in consideration of the movement, that is, movement of the puncture needle inserted into the target site.

The tip candidate processing unit 76 emphasizes display on one or more predetermined number of tip candidates detected by the tip candidate detecting unit 74 or their coordinates so that the surgeon can easily identify them when displayed on the display unit 52. Processing is performed to generate an image of the tip candidate of the puncture needle whose display is highlighted, that is, a tip image in which the tip candidate of the puncture needle is displayed and emphasized.
In the tip candidate processing unit 76, it is preferable to color the tip candidates of the puncture needle detected by the tip candidate detecting unit 74 and generate a color tip image for color display as display enhancement processing. It is preferable to generate a high-luminance tip image by increasing the luminance of the image, or to generate a high-luminance color tip image by increasing the luminance after coloring the tip candidates.

The number of tip candidates and their coordinates to be colored or increased in brightness is preferably one, but may be two or more, or tip candidates detected in the past and their coordinates may be used. Also, as shown in FIG. 4, the tip candidate processing unit 76 displays the tip image of the puncture needle detected at the past time in a highlighted manner and is superimposed on the display unit 52 so that the locus of the puncture needle is displayed. Anyway.
The tip candidate of the puncture needle and the region for coloring or increasing the brightness of the coordinate may be the tip candidate region itself, or an arbitrary region of the tip candidate coordinate, for example, a rectangle, an ellipse, It may be an area such as a perfect circle or a square. Further, the size of the area can be set in advance, and may be changed during scanning of the ultrasonic probe 12 by assignment of a function key or the like.
Furthermore, for the region to be colored or increased in luminance, weighting by a tip emphasis filter when the tip candidate detection unit 74 detects a tip candidate may be used.

Here, the tip candidate detection unit 74 determines whether the luminance difference of the difference image is positive or negative, and the tip candidate processing unit 76 determines whether the tip of the difference image is positive or negative according to the positive or negative of the difference in luminance of the difference image. It is preferable to perform display emphasis processing on the tip candidates of the puncture needle detected by the candidate detection unit 74, and more preferably, the hue and brightness for display enhancement processing of the tip candidates of the puncture needle detected by the tip candidate detection unit 74 are changed. Good to do. In this way, by changing the hue and luminance of the tip candidate subjected to display enhancement processing and displaying it on the display unit 52, for example, when the difference in luminance of the difference image is positive, the puncture needle is inserted at the time of insertion into the target region. the tip portion can be visually recognized, if negative, you have the effect that it is possible to visually recognize the distal end of the puncture needle when pulling out the puncture needle.
Further, the tip candidate detection unit 74 does not determine whether the luminance difference of the difference image is positive or negative, and the tip candidate processing unit 76 generates and displays a color tip image colored or increased in brightness with the absolute value of the luminance difference. You may display on the part 52. FIG.

The tip candidate storage unit 78 is configured by a memory, a hard disk, or the like, and stores tip candidates (its position (coordinates), size, and the like) detected by the tip candidate detection unit 74. The tip candidate storage unit 78 may store a plurality of tip candidates at past times.
The tip candidate storage unit 78 uses a plurality of tip candidates stored in the past time for use in detection by the tip candidate detection unit 74, such as an extraction processing unit 82 or a specific processing unit of the tip candidate detection unit 74. And output to the tip candidate processing unit 76 for display enhancement processing in the tip candidate processing unit 76 and display on the display unit 52.

  The puncture needle information and condition storage unit 80 is configured by a memory, a hard disk, or the like, and information on the puncture needle, detection conditions for detecting a tip candidate in the tip candidate detection unit 74, processing conditions for detection processing, tip candidate processing This is a storage unit for storing processing conditions for display enhancement processing in the unit 76. Here, the information about the puncture needle includes the type, thickness, insertion position (position where the puncture needle is inserted into the subject), and insertion angle (the puncture needle is inserted into the subject). Angle), insertion path, puncture target (object or part), and the like. Further, the detection conditions and processing conditions are specifically the extraction conditions of the tip candidate points extracted by the tip candidate detection unit 74, for example, the luminance difference of the difference image, the size of the luminance value, the density and size of the extraction points. Conditions such as threshold values, various filters such as various LUTs and tip emphasis filters used for extraction, conditions such as size and weight, coloring of tip candidates of tip candidates in the tip candidate processing unit 76, This is the processing conditions such as the content of the tip candidate display enhancement processing such as increasing the brightness and increasing the brightness, and the size and shape of the target tip candidate region.

The information storage unit 80 acquires and stores information related to the puncture needle and detection conditions and processing conditions of the tip candidate through the main body control unit 54 by input from the user via the operation unit 56, and stores the stored information and conditions. Is output to the extraction processing unit 82 and the specific processing unit 84 of the tip candidate detection unit 74 and also to the tip candidate processing unit 76.
The tip detection unit 70 is basically configured as described above.

Next, a preferable configuration of the difference image generation unit 68 shown in FIG. 1 will be described.
FIG. 6 is a block diagram illustrating an embodiment of the time-series frame difference image generation unit of the composite image generation unit illustrated in FIG.
As shown in FIG. 6, the difference image generation unit 68 includes a preprocessing unit 86 and a difference processing unit 88. The preprocessing unit 86 includes a speckle noise removal unit 90, a layer structure removal unit 92, and the like. And a puncture needle processing unit 94.

The preprocessing unit 86 generates the puncture needle in the difference image before generating the difference image between the B-mode image signals of the two time-series frames generated by the image generation unit 64 and stored in the frame image storage unit 66. In order to increase the accuracy of detection of the front end portion, noise or layer structure removal processing is performed on a B-mode image signal (frame image) of at least one frame out of two time-series frames to be subjected to difference processing, Preprocessing such as puncture needle emphasis processing and puncture needle image connection processing is performed. Signal processing such as puncture needle emphasis processing and puncture needle image connection processing is performed to clarify the puncture needle with respect to the B-mode image signal after noise removal.
By the way, the pre-processing unit 86 preferably includes all of the speckle noise removing unit 90 , the layer structure removing unit 92 , and the puncture needle processing unit 94, but may include at least one.

The difference processing unit 88 obtains a difference between the B-mode image signals (images) of the two time-series frames from which the speckle noise and the layer structure are removed, and generates a difference image (difference image signal).
Here, the difference processing unit 88 has a function of adjusting the time difference between two time-series frames for creating a difference image because the insertion speed of the puncture needle changes depending on the procedure of the examiner or operator. It is preferable that the frame interval of the time series frame can be arbitrarily set. In addition, it is preferable to use a plurality of frames two or more frames before as the past frame for creating the difference image. Note that the difference image (pixel signal) may also include the absolute value of the difference value.
Note that the difference image generation unit 68 preferably includes the preprocessing unit 86 and the difference processing unit 88, but if the difference processing unit 88 is included, the preprocessing unit 86 may not be included.

The speckle noise removing unit 90 performs the B processing as a pre-process of the difference processing of the B-mode image signals (frame images) of two time-series frames generated by the image generating unit 64 and stored in the image storage unit 66. Signal processing is performed to reduce the speckle pattern of the mode image signal, and speckle noise is removed. For example, a median filter is preferably applied to the speckle noise removal process, but a spatial compound method, a frequency compound method, a morphology process, or the like may be applied.
The layer structure removal unit 92 performs a layer structure removal process on the B-mode image signal from which speckle noise has been removed by the speckle noise removal unit 90, and removes bright lines extending in the direction of the puncture needle. For example, CFAR (Constant False Alarm Rate) processing and MIP (Maximum intensity projection) processing are performed. As the CFAR process, a method described in JP-A-2006-305337 can be used.
In this way, by performing the layer structure removing process in the layer structure removing unit 92, the connecting portion other than the puncture needle can be removed in the subsequent signal processing by the puncture needle processing unit 94.

Further, the puncture needle processing unit 94 performs signal processing for connecting the puncture needle by blurring in the direction of the puncture needle and signal processing for connecting the puncture needle from the characteristic points of the puncture needle in order to clarify the puncture needle of the frame image. . Therefore, the puncture needle processing unit 94 is a puncture needle emphasis processing unit 94a that performs signal processing to blur the puncture needle in the direction of the puncture needle, and a puncture needle connection process that performs signal processing to connect the puncture needle from the characteristic points of the puncture needle At least one of the part 94b is provided.
FIG. 7 shows a puncture needle enhancement processing unit which is an embodiment of the puncture needle processing unit of the time-series frame difference image generation unit shown in FIG.
The puncture needle enhancement processing unit 94a includes a filter application processing unit 96 and an edge enhancement processing unit 98, as shown in FIG.

  The filter application processing unit 96 applies a blur filter to the B-mode image signal from which noise such as speckle noise or layer structure has been removed by the layer structure removing unit 92 or the speckle noise removing unit 90. That is, the filter application processing unit 96 identifies a blur filter to be used based on the insertion angle stored in the information storage unit 80 and reads it from the information storage unit 80. For example, when the insertion angle is 10 degrees, Then, the blur filter for the insertion angle of 10 degrees is read, and the read blur filter is applied to the B-mode image data after noise removal. Since the blur filter used here is a filter that matches the puncture angle of the puncture needle, it is possible to blur the image in the direction in which the puncture needle is inserted and to improve the connection of the puncture needle image that has been interrupted. it can.

  The edge enhancement processing unit 102 performs edge enhancement processing of the B mode image on the B mode image data to which the blur filter is applied. Thereafter, for example, a one-dimensional edge enhancement process in the vertical direction is performed on the puncture needle to emphasize the edge of the puncture needle. Before output to the difference processing unit 88, the B-mode image (image data) after emphasizing the edge and the original B-mode image (image data), which are better connected in the direction in which the puncture needle is inserted, are used. May be combined to generate a composite frame image (image data). Thereby, the frame image in which the whole image of the puncture needle in the tissue is clarified can be output to the difference processing unit 88.

Note that the blur filter used for the signal processing to blur the direction of the puncture needle in the filter application processing unit 96 is similar to the tip emphasis filter filter used in the tip detection unit 70 described above, and the shape of the puncture needle is stepped. A filter in a form that uses pixels in the insertion direction for weighted addition, or a filter that performs weighted addition in which the filter shape is rectangular and the filter coefficient of the pixel in the direction in which the puncture needle is inserted is large Can be used. Here, when such a filter is used as a blurring filter, the tip emphasis filter used in the tip detection unit 70 is weighted in the insertion direction of the puncture needle in the frame image so as to have a size including the puncture needle. It is necessary to create a puncture needle emphasis filter.
That is, in the filter application processing unit 96, as shown in FIG. 5B, as the blurring filter, a weighted addition is performed in which the filter shape is rectangular and the filter coefficient of the pixel in the direction in which the puncture needle is inserted is large. The puncture needle emphasis filter of the aspect to perform can also be used.

FIG. 8 shows an example in which such a puncture needle enhancement filter is applied to a B-mode image (frame image) of one frame in accordance with the insertion direction or the insertion angle of the puncture needle.
8A, 8B, and 8C show a frame image (B-mode image), a puncture needle enhancement filter, and a puncture needle enhancement image, respectively.
Here, the frame image shown in FIG. 8 (A) is an ultrasonic image (B) of one frame that is processed by the filter application processing unit 96 of the puncture needle processing unit 94a shown in FIG. Mode image).
The puncture needle enhancement filter shown in FIG. 8B is a puncture needle enhancement filter having a size of 55 pixels vertically and 6 pixels horizontally, which is applied to the one-frame image shown in FIG. 8A.
The puncture needle enhancement image shown in FIG. 8C is a puncture needle enhancement ultrasound image obtained by applying a puncture needle enhancement filter to the frame image in accordance with the insertion direction or the insertion angle of the puncture needle. Yes, the B-mode image before the puncture needle enhancement processing is an image that is blurred in the insertion angle direction. Therefore, as shown in FIG. 8C, the puncture needle is connected and displayed in the obtained puncture needle emphasized image.
In FIGS. 8A and 8C, speckle noise removal, layer structure removal, and edge enhancement are not performed in order to make the difference between the puncture needle enhancement filter processes easier to understand.

As described above, the puncture needle emphasis filter shown in FIG. 8B is based on the tip emphasis filter shown in FIG. 5B and linearly interpolates so as to be the size of the puncture needle emphasis filter. Filter coefficients used for the filter can be generated. That is, a puncture needle having a size of 55 pixels vertically and 6 pixels horizontally shown in FIG. 8B by linearly interpolating a filter having a size of 81 × 81 shown in FIG. 5B. Emphasis filters can be created. The puncture needle emphasis filter having a size of 55 pixels in the vertical direction and 6 pixels in the horizontal direction thus obtained is a puncture needle emphasis filter when the insertion angle is 10 degrees. The aspect ratio by linear interpolation is determined according to the insertion angle. Also in this puncture needle emphasis filter, the filter coefficient at the center is the largest, and then the filter coefficient is widely distributed along the direction in which the puncture needle is inserted. The target pixel at the center is weighted and added using 55 pixels in the vertical direction and 6 pixels in the horizontal direction centering on the target pixel. A value obtained by multiplying the value of each pixel by the filter coefficient of the puncture needle emphasis filter and performing weighted addition becomes the value of the target pixel. The puncture needle emphasis filter having an aspect ratio corresponding to the insertion angle created in this way is stored in the information storage unit 80.

In the present embodiment, a puncture needle emphasis filter to be used is determined according to the puncture angle, and puncture needle emphasis processing is performed for all pixels using the determined puncture needle emphasis filter to perform weighted addition with surrounding pixels. And an image obtained by emphasizing the puncture needle can be generated.
Note that, here, the case of converting to a size of 55 pixels in the vertical direction and 6 pixels in the horizontal direction has been described as an example. However, in the puncture needle emphasis filter having different sizes, the vertical 81 × horizontal shown in FIG. By performing linear interpolation on a filter having a size of 81, a filter coefficient corresponding to the size of each puncture needle emphasis filter can be generated.

Such a blur filter such as a puncture needle emphasis filter is preferably of a size large enough to include an interval at which the puncture needle is interrupted. The blur filter has a plurality of sizes, for example, “large, medium, small” according to the thickness of the puncture needle, and “10 °, 30 °, 60 °” according to the insertion angle of the puncture needle. A plurality of types may be prepared between 10 ° and 60 °. Multiple types may be prepared. Alternatively, the size may be determined using puncture information such as the puncture needle size (G), puncture purpose (FNA, CNB, RFA, etc.), and puncture angle.
Further, a Gaussian filter or the like may be used as a weighting filter used for signal processing to blur in the direction of the puncture needle. In this case, the weight ratio may be prepared as a parameter that allows the user to change the average, variance, correlation, and the like.

The blur filter size and the weight of the weighting filter may be changed in advance by the user on the setting screen, or a function is assigned to a function key or the like and changed during scanning of the ultrasonic probe 12. You may be able to do it.
As the blur filter, for example, it has been puncture device enhancement processing described 2010-216512 Patent Application No. a copending application of the present applicant "ultrasonic image generating apparatus and an ultrasonic image generating method" Various puncture device emphasis filters used in the above can be mentioned.
The signal processing for blurring in the direction of the puncture needle by the filter application processing unit 96 includes puncture needle enhancement processing using a puncture needle enhancement filter as a blurring filter. For example, the above-mentioned Japanese Patent Application No. 2010-216512 it can be applied to the puncture device enhancement processing described in "ultrasonic imaging apparatus and an ultrasonic image generating method."

That is, as the blurring filter, a puncture device emphasis filter in which the filter shape is stepped and pixels in the direction in which the puncture needle is inserted is used for weighted addition can be used. That is, a puncture needle emphasis filter that weights and adds a value (image data) of a target pixel (hereinafter referred to as target pixel) to be subjected to puncture needle emphasis processing to a value (image data) of a specific pixel around the target pixel is used. be able to. At this time, the filter application processing unit 96 sequentially changes the position of the target pixel, and puncture needle emphasis by the puncture needle emphasis filter determined according to the puncture angle is performed on the image data of all the pixels in the B-mode image. Process.
As such a puncture needle emphasis filter, a plurality of filter elements are arranged in one row, and a plurality of rows are connected in a staircase pattern while shifting the rows in accordance with the insertion angle. A filter having a filter coefficient that increases or decreases on both sides with respect to the filter coefficient of the target pixel can be given as a target pixel having an element at the center or substantially at the center.
The filter coefficient of such a puncture needle emphasis filter is generated using, for example, a Gaussian filter expressed by the following equation (2).

Here, μ is the average, σ ² is the variance, and x is the position of the pixel in the vertical direction of the drawing when the central element is 0. For example, x = −1 and x = 1 are the positions of adjacent pixels before and after the central element or on the left and right. As described above, by determining the filter coefficient of each pixel using the Gaussian filter, it is possible to perform weighted addition in which the filter coefficient of the pixel near the target pixel is further increased.

FIG. 9 shows a puncture needle connection processing unit which is an embodiment of the puncture needle processing unit of the time-series frame difference image generation unit shown in FIG.
The puncture needle connection processing unit 94b performs signal processing for connecting the puncture needle from the feature point of the puncture needle. As such signal processing, for example, a process of displaying a straight line by using a feature point of a puncture needle and using a Hough transform or the like, a process of fitting a straight line with a least square error using a feature point of a puncture needle, For example, the position coordinates of the feature point representing the tip of the puncture needle can be stored in the memory for an arbitrary period and connected by straight lines or curves passing through all the points.
As shown in FIG. 9, the puncture needle connection processing unit 94b includes a puncture needle candidate point extraction unit 100, a candidate point position storage unit 102, a puncture needle region specifying unit 104, and a puncture needle tip position specifying unit 106. And a puncture needle image generation unit 108 and a puncture needle connection image generation unit 110.

  The puncture needle feature point extraction unit (hereinafter referred to as the feature point extraction unit) 100 uses the information on the puncture needle stored in the information storage unit 80 and the layer structure removal unit 92 and the speckle noise removal unit 90 to perform speckle noise and layer structure. A feature point of the puncture needle is extracted using B-mode image data from which noise such as the above has been removed. Specifically, an edge extraction filter is applied to the B-mode image data, threshold processing is performed to create edge image data, and feature points on the puncture needle are extracted from the edge image data. Since the puncture needle has a smooth surface and is difficult to scatter ultrasonic waves, the puncture needle is displayed in an intermittent manner in the B-mode image. Therefore, if threshold processing is performed on B-mode image data in which a puncture needle is present, feature points representing a part of the puncture needle that has been interrupted can be extracted. The time interval for extracting the feature points of the puncture needle can be changed by the user. In the B-mode image, there are also high-luminance points derived from other than the puncture needle such as tissue, so that the feature points extracted by the threshold processing are not only those derived from the puncture needle. The puncture needle feature point derived from tissue or the like becomes noise when the position of the puncture needle is specified based on the edge image.

A feature point position storage unit (hereinafter referred to as a position storage unit) 102 stores the positions of all puncture needle feature points extracted by the feature point extraction unit 100, and the positions of the puncture needle feature points are determined as a puncture needle region specifying unit ( (Hereinafter referred to as area specifying unit) 104.
The area specifying unit 104 generates a straight line (puncture needle candidate straight line) representing the puncture needle and an extension line of the puncture needle based on the distribution of the plurality of puncture needle feature points stored in the position storage unit 102. The area specifying unit 104 specifies an area including the generated straight line as an area where the puncture needle is present.
A puncture needle tip position specifying unit (hereinafter referred to as a position specifying unit) 106 specifies the tip position of the puncture needle based on luminance information of a region where the puncture needle specified by the region specifying unit 104 is likely to exist, The identified tip position is output to the puncture needle image generation unit 108.

The puncture needle image generation unit 108 selects the puncture needle based on the puncture needle generated by the region specifying unit 104 and the straight line representing the extension line of the puncture needle and the tip position of the puncture needle specified by the position specifying unit 106. An image to be represented is generated and output to a puncture needle connected image generation unit (hereinafter referred to as a connected image generation unit) 110. The user can select an image representing the puncture needle from various forms. For example, there are a form in which the puncture needle is represented by a straight line, a form in which the outline of the puncture needle is represented, a form in which the puncture needle is represented as a set of points, and the like. Here, when expressing the outline of the puncture needle, the outline of the puncture needle is generated by reading out the puncture needle information from the information storage unit 80. Further, the brightness representing the puncture needle can be set by the user. For example, the luminance of the image representing the puncture needle may be the luminance that the user likes, or may be the same level as the luminance of the portion that appears to be the puncture needle in the B-mode image.
The connected image generation unit 110 combines the B-mode image data output from the layer structure removal unit 92 with the combined B-mode image data generated by the puncture needle image generation unit 108 and superimposed on the image representing the connected puncture needle. Is generated. The connected image generation unit 110 outputs the composite B mode image data to the difference processing unit 88.

FIG. 10 is a functional block diagram showing a more detailed configuration of puncture needle region specifying unit 104 and puncture needle tip position specifying unit 106 shown in FIG.
The region specifying unit 104 includes a puncture needle straight line generation unit 112 and a puncture needle region generation unit 114.
A puncture needle straight line generation unit (hereinafter referred to as a straight line generation unit) 112 performs Hough transform on the puncture needle feature points distributed in the B-mode image output from the position storage unit 102 to generate a puncture needle candidate straight line. . The puncture needle candidate straight line is a straight line that passes through the most puncture needle feature points. The straight line generation unit 112 outputs the position coordinates of the points on the generated puncture needle candidate straight line to a puncture needle region generation unit (hereinafter referred to as a region generation unit) 114.

The region generation unit 114 expands the puncture needle candidate straight line generated by the straight line generation unit 112 to a predetermined width, and specifies the region included in the puncture needle candidate straight line as a region where the puncture needle exists (puncture needle presence region). The region generation unit 114 outputs the position coordinates of the points included in the specified puncture needle presence region to the position specifying unit 106.
The position specifying unit 106 includes an average luminance calculating unit 116, a maximum luminance specifying unit 118, a minimum luminance specifying unit 120, and a puncture needle tip position calculating unit 122.

A method for obtaining the tip position of the puncture needle from the B-mode image and a method for generating an image representing the puncture needle will be described in more detail with reference to FIGS. 11 (A) to 11 (D) and FIGS. 12 (A) to 12 (B). A function of each component of the position specifying unit 106 will also be described.
In FIG. 11A, XY with the upper left corner of the B mode image as the origin, the horizontal axis from the upper left corner to the upper right corner as the X axis, and the vertical axis from the upper left corner to the lower left corner as the Y axis. Consider a case where an image is located in an orthogonal coordinate system. The direction from the upper left end of the B mode image to the upper right end is the positive direction of the X axis, and the direction from the upper left end of the B mode image to the lower left end of the B mode image is the positive direction of the Y axis. Hereinafter, unless otherwise specified, the definition of the XY orthogonal coordinate system for images is the same.

FIG. 11A shows a B-mode image of a subject including a puncture needle. The puncture needle in FIG. 11 (A) is displayed in an intermittent manner, and it is difficult to understand the exact position of the puncture needle. Therefore, the puncture needle connection processing unit 94b first identifies an area where the puncture needle is likely to exist from the B-mode image as shown in FIG. 11A, and the linear intensity including the puncture needle in the area. The tip position of the puncture needle is specified from the distribution. The puncture needle connection processing unit 94b generates an image representing the puncture needle based on the tip position of the puncture needle, superimposes it on the B-mode image, and outputs it to the difference processing unit 88.
The feature point extraction unit 100 applies an edge extraction filter (weighted addition filter) corresponding to the puncture angle of the puncture needle to the B-mode image shown in FIG. Improve image connection. Further, the feature point extraction unit 100 performs threshold processing on the B-mode image to which the edge extraction filter is applied, and an edge image in which only feature points (puncture needle feature points) having a luminance equal to or higher than the threshold value remain white (FIG. 11). (See (B)). The straight line generation unit 112 obtains the position of the puncture needle candidate straight line from the distribution of the puncture needle feature points in the edge image.

  In the edge image shown in FIG. 11B, a plurality of puncture needle feature points displayed with high luminance in the B-mode image are distributed. Each puncture needle feature point distributed in the edge image is a point derived from the puncture needle mainly at the position where the puncture needle is present, and appears on the entire screen regardless of the position where the puncture needle is present. This is a point derived from something other than a puncture needle such as tissue. The puncture needle feature point derived from tissue or the like becomes noise when the position of the puncture needle is specified based on the edge image. Accordingly, the straight line generation unit 112 performs Hough transform on the edge image including noise as illustrated in FIG. 11B, and generates a puncture needle candidate straight line that passes through the most puncture needle feature points derived from the puncture needle. To do. Even if the edge image contains noise, the puncture needle feature point derived from the puncture needle has a linear connection, so a straight line along the linear connection by the puncture needle feature point derived from the puncture needle is generated by the Hough transform. it can. An image obtained by superimposing the generated puncture needle candidate straight line 130 on the edge image data is shown in FIG. A puncture needle candidate straight line 130 in FIG. 11C represents the puncture needle and an extension line of the puncture needle.

  Since the puncture needle and the puncture needle candidate straight line 130 representing the extension of the puncture needle are unclear on the boundary between the puncture needle and the non-puncture needle, the boundary between the puncture needle and the non-puncture needle portion on the puncture needle candidate straight line 130 The position, that is, the tip position of the puncture needle is obtained. FIG. 11D shows an edge image in which the puncture needle candidate straight line 130 generated by the Hough transform is expanded to a predetermined width by the region generation unit 114 and the region 132 is superimposed and displayed. Region 132 is a region including puncture needle candidate straight line 130. The region generation unit 114 identifies the region 132 as a puncture needle presence region where a puncture needle is present. Since the puncture needle candidate straight line 130 extracted by the Hough transform is a straight line that passes through many puncture needle feature points derived from the puncture needle, an area including many puncture needle feature points is specified as the puncture needle presence area 132. The puncture needle connection processing unit 94b creates the region 132 in this way, and narrows down the region where the puncture needle is likely to exist. Here, the predetermined width for expanding the puncture needle candidate straight line 130 may be the thickness of the puncture needle read from the information storage unit 80, or may be set by the user while viewing the B-mode image or the edge image.

  Next, the average luminance calculation unit 116 of the position specifying unit 106 rotates the edge image shown in FIG. 11D until the longitudinal direction of the region 132 becomes horizontal, and the longitudinal direction of the region 132 is the X ′ axis and the region 132. The X′Y ′ orthogonal coordinate system is defined with the short direction of Y ′ as the Y ′ axis. The average luminance calculation unit 116 performs addition averaging of points arranged in the Y ′ coordinate direction (points having the same X ′ coordinate value) in the region 132. FIG. 12A shows a method of specifying the tip position from the region 132, and therefore, the region 132 in the edge image and the straight line including the puncture needle in the region 132 (the value of the X ′ coordinate in the region 132 is the same) It is the figure which matched and showed the graph which shows distribution of the average brightness | luminance of the area | region 132) which became one-dimensional as a result of carrying out the addition average of the point. The graph shown in FIG. 12A represents an average luminance distribution viewed from the scanning direction (X ′ direction) in the region 132, with the horizontal axis representing the position on the X ′ coordinate and the vertical axis representing the average luminance. The maximum brightness specifying unit 118 and the minimum brightness specifying unit 120 obtain the maximum value and the minimum value of the average brightness based on the graph shown in FIG. Note that the graph shown in FIG. 12A is simplified for easy understanding.

  The puncture needle tip position calculation unit (hereinafter referred to as position calculation unit) 122 calculates the X ′ coordinate with respect to the graph representing the relationship between the position on the X ′ coordinate and the average luminance in the region 132 shown in FIG. The average luminance value is examined from the maximum value side toward the origin side, and the tip position of the puncture needle is specified. Specifically, the position calculation unit 122 increases the average luminance, which is a value near the minimum value because there is no puncture needle, greatly increases, and is 80% luminance for the first time with respect to the difference between the maximum value and the minimum value. The resulting point 134 is specified as the tip position of the puncture needle. Here, the reason for examining from the maximum value side of the X ′ coordinate is that a significant change in luminance can be specified as the tip position of the puncture needle by examining from the side where the puncture needle is expected not to exist. . When examined from the origin side, there is a possibility that the average luminance shows a value near the minimum value at a position where the puncture needle is interrupted, and then the point where the puncture needle is detected is identified as the tip. Here, 80% of the difference between the maximum value and the minimum value is empirically desirable as the point at which the tip of the puncture needle can be substantially specified. It may not be 80%. However, if a point that is very close to the minimum value side of the average brightness is set, noise may be set as the tip position. Therefore, a point that is 50% or more of the difference between the maximum value and the minimum value of the average brightness is desirable.

  Within the area 132, the average luminance of the area where no puncture needle is present is approximately zero. Therefore, when the average luminance value is examined from the maximum value side of the X ′ coordinate where there is no puncture needle toward the 0 side, the value near 0 continues for a while. When entering the region where the puncture needle is present from the region where the puncture needle is not present, the average luminance increases rapidly. This is because the puncture needle is detected with high brightness. The position calculation unit 122 identifies the point 134 that is the tip position of the puncture needle based on such a change in average luminance due to the presence or absence of the puncture needle. The puncture needle tip position calculation unit 122 that has identified the point 134 that is the tip position of the puncture needle converts the X′Y ′ orthogonal coordinate system to the XY orthogonal coordinate system, and obtains the X coordinate and Y coordinate of the point 134.

  The puncture needle image generation unit 108 generates a straight line representing the puncture needle based on the puncture needle candidate straight line 130 and the tip position 134 of the puncture needle. Specifically, the puncture needle candidate straight line 130 is punctured as a line segment from the position of the X coordinate 0 to the point 136 on the puncture needle candidate straight line 130 having the same X coordinate as the X coordinate of the tip position 134 of the puncture needle. A line segment 140 that is a straight line representing the needle is generated. FIG. 12B is a schematic diagram depicting a line segment 140 generated by the puncture needle image generation unit 108. A point 138 in FIG. 12B is a point where the puncture needle candidate straight line 130 intersects the left side of the edge image.

The puncture needle connection processing unit 94b repeats detection of the tip position of the puncture needle and generation of an image representing the puncture needle at predetermined time intervals, and superimposes the image representing the most recently generated puncture needle on the B-mode image, The data is output to the difference processing unit 88. The puncture needle connection processing unit 94b identifies the tip position of the puncture needle, and superimposes the generated puncture needle image (an image representing the puncture needle) on the B-mode image, whereby the position of the puncture needle is clarified. Can be output to the difference processing unit 88.
The puncture instrument connecting process for connecting the puncture needle is described in, for example, Japanese Patent Application No. 2010-216764 “Sound image generation apparatus and ultrasonic image generation method” which is a continuation application simultaneously filed by the present applicant. A puncture needle connection process can be applied.
The puncture needle connection processing performed in the puncture needle connection processing unit 94b may be performed as the LUT processing performed in the tip detection unit 70.
The ultrasonic diagnostic imaging apparatus of the present invention is basically configured as described above.

The operation of the ultrasonic diagnostic imaging apparatus of the present invention and the ultrasonic image generation method of the present invention will be described below.
FIG. 13 is a flowchart showing an example of a main part of the ultrasonic image generation method of the present invention, and a composite image in which a tip image in which a tip candidate of a puncture needle is colored from the difference image generation step is superimposed on a B-mode image. This shows up to the generation step.
First, the operator contacts the ultrasonic transmission / reception surface of the ultrasonic probe 12 with the surface of the subject. In this state, ultrasonic waves are transmitted from the plurality of transducers 34 in accordance with the drive signal supplied from the transmission drive unit 38 of the probe main body 16, and the reception signals output from the transducers 34 that have received the ultrasonic echoes from the subject are Sample data is generated by being supplied to the corresponding reception signal processing unit 36, transmitted to the diagnostic apparatus main body 14 via the communication cable 18, and stored in the data storage unit 46. Further, the sample data for each frame is read from the data storage unit 46, the B-mode image data for each frame is generated by the image generation unit 64 of the composite image generation unit 48, and the B-mode image data of the time-series frame is It is stored in the frame image storage unit 66.

Next, according to FIG. 13, a composite image is generated in which the tip image in which the tip candidate of the puncture needle is colored as display enhancement processing is superimposed on the B-mode image.
As shown in FIG. 13, first, in step S10, two time series of a frame before and the current frame shown in FIGS. 14A and 14B read from the frame image storage unit 66 are displayed. The difference image generation unit 68 performs difference processing from the B-mode image data of the frame to generate a frame difference image shown in FIG.

Next, in step S12, the candidate point extraction unit 82 of the tip candidate detection unit 74 of the tip detection unit 70 performs LUT processing to which the tip enhancement filter shown in FIG. 14D is applied, and extracts tip candidate points. The tip emphasis filter shown in FIG. 14D is a rectangular filter of 15 pixels in the vertical direction and 27 pixels in the horizontal direction for blurring along the insertion direction of the puncture needle. The Gaussian filter shown in FIG. Has filter coefficients weighted along the direction. FIG. 14E shows an LUT-processed image that has been subjected to the LUT process using the tip enhancement filter.
FIG. 16 shows the distribution of the tip candidate points of the puncture needles in the rectangular area including the puncture needle tips in the processed image obtained by performing the binarization process using the luminance difference on the difference image of the frame shown in FIG. Show. As can be seen from the figure, after the binarization process, there are a plurality of puncture needle tip candidate points other than the vicinity of the puncture needle tip.

Subsequently, in step S14, the tip candidate specifying processing unit 84 specifies only the center point of the tip candidate point of the puncture needle, particularly the region having a high correlation with the tip portion, as the tip candidate.
In step 16, it is determined whether or not the extraction / specification of the tip candidate in the difference image has been completed by the tip candidate specification processing unit 84, and if it has not ended, the process returns to step S <b> 14 and continues to extract and specify the tip candidate. If completed, the process proceeds to step S18.
In step S18, the tip candidate processing unit 76 colors the tip candidates specified in step S14 to generate a tip image.
Next, in step S20, the image combining unit 72 combines the tip image generated in step S18 and the ultrasonic image (B-mode image) of the current frame, and the tip candidate colored by the tip candidate processing unit 76. Is superimposed on the ultrasonic image of the current frame.
Next, in step 22, it is determined whether or not the composite image generation processing has been completed by the image composition unit 72. If not, the process returns to step S 10 to generate the composite image in step S 20 from the difference image generation. The process is repeated until the process is completed.

Thereafter, the synthesized image synthesized by the image synthesizing unit 72 is sent to the display control unit 50, converted into a synthesized image signal for display, and the colored tip candidates are converted into an ultrasonic image of the current frame on the display unit 52. The superimposed composite image is displayed.
As described above, the ultrasonic image generation method of the present invention is implemented.
The example illustrated in FIG. 13 is an example in which the tip candidate is always detected from the difference image, but naturally includes a case where the tip candidate is not detected. Therefore, processing including a case where the tip candidate is not detected will be described below.

FIG. 17 is a flowchart illustrating an example including a case where a tip candidate is not detected in the ultrasonic image generation method of the present invention.
First, in step S30, difference image data for the current frame is generated by subtracting B-mode image data for the current frame from frame B-mode image data before the current frame.
Next, in step S32, LUT processing and tip candidate specification processing are performed on the difference image data to detect a tip candidate of the puncture needle.
In step 34, it is determined whether or not the tip candidate of the puncture needle has been detected in step S32. If detected, the process proceeds to step 36 as a successful detection, and if not detected, the process proceeds to step 46.

In step S36, the detection information including information on the tip candidate of the puncture needle detected in step S32 is stored in the memory (tip candidate storage unit 78) and saved.
In step S38, the detected tip candidate is read from the memory, the read tip candidate is colored, and a tip image of the puncture needle is generated.
In step S40, the tip image generated in step S38 is superimposed on the ultrasound image (B-mode image) of the current frame to generate a composite image in which the colored tip candidates are superimposed on the ultrasound image of the current frame. .
In step 42, a composite image in which the colored tip candidates are superimposed on the ultrasonic image of the current frame is displayed on the display unit 52.
Next, in step 44, it is determined whether or not to continue detection of the tip candidate of the puncture needle and display of the composite image. If so, the process returns to step S30 to generate the composite image of step S42 from the generation of the difference image data. The process is repeated until the display of, and if not continued, this process ends.

On the other hand, if it is determined in step 34 that the detection of the tip candidate of the puncture needle is unsuccessful, it is determined in step 46 whether or not the detection information of the tip candidate of the past puncture needle in the memory is used. If it is used, the process proceeds to step 48, and if it is not used, the process proceeds to step 50.
In step 48, using the detection information read from the memory, the past tip candidates of the puncture needle are colored to generate a tip image of the puncture needle, and the process proceeds to step S40. In step S40, the tip image of the puncture needle generated in step 48 is superimposed on the ultrasonic image (B-mode image) of the current frame to generate a composite image.
In step 50, since there is no detection information and no tip candidate exists in step 50, the ultrasonic image of the current frame is displayed on the display unit 52, and the process proceeds to step S44. In step 44, as described above, it is determined whether or not the detection is continued, the detection is continued according to the determination, and the process is ended.

  In the embodiment shown in FIG. 1, as described above, based on the B-mode image signal generated by the image processing unit 62 of the image generation unit 64, the generation of the difference image of the two frames, the detection of the tip candidate, and the tip image Are generated, and the leading edge image and the ultrasonic image (B mode image) of the current frame are superimposed and synthesized. However, the present invention is not limited to this, and instead of the B mode image signal, as shown in FIG. In addition, based on the baseband signal (sound ray signal) that has been subjected to the beam forming processing in the phasing addition unit 60 of the image generation unit 64, that is, the echo signal for each frame, the generation of the difference image of the two frames, the tip candidate Detection, generation of the tip image, and superposition synthesis of the tip image and the ultrasonic image of the current frame may be performed. Therefore, in the present invention, any signal between the frame echo signal and the B-mode image signal may be used.

FIG. 18 is a block diagram schematically showing the configuration of another embodiment of the diagnostic apparatus main body of the ultrasonic diagnostic apparatus of the present invention.
The diagnostic apparatus main body 14a shown in the figure has a data storage unit 46, a composite image generation unit 48a, and a display unit 52. Further, although not shown, a main body control unit, an operation unit, as in FIG. And a storage unit. The composite image generation unit 48a includes an image generation unit 64, a time-series frame echo signal storage unit (hereinafter also referred to as an echo signal storage unit) 66a, and a time-series frame difference echo signal generation unit (hereinafter simply referred to as a differential echo signal). 68a, a puncture needle tip detection unit (tip detection unit) 70a, and an image composition unit 72a.
The echo signal storage unit 66a, the differential echo signal generation unit 68a, the tip detection unit 70a, and the image synthesis unit 72a of the composite image generation unit 48a of the diagnostic device main body 14a shown in FIG. The image storage unit 66, the difference image generation unit 68, the tip detection unit 70, and the image synthesis unit 72 of the composite image generation unit 48 perform processing of each element based on the echo signal, or based on the B-mode image signal The only difference is in whether each element is processed, that is, only the signal (data) to be processed is different, and the contents of each process are substantially the same. The detailed description is omitted.

The echo signal storage unit 66a is a memory that stores echo signals representing images of a plurality of frames in time series.
The differential echo signal generation unit 68a obtains a difference between the echo signals of two time-series frames stored in the echo signal storage unit 66a, and generates a differential echo signal.
The tip detection unit 70a is the most characteristic part of the present invention, and performs tip detection processing from the differential echo signal generated by the differential echo signal generation unit 68a to obtain one or more tip candidates including the tip of the puncture needle. Detection is performed, display enhancement processing is performed on the detected tip candidate, and a tip image subjected to display enhancement processing is generated. It should be noted that the tip candidate detected from the differential echo signal is subjected to conversion processing similar to that of the image processing unit 62 to obtain a B-mode image signal, and the tip image is represented by the B-mode image signal. Is preferred.

The image synthesis unit 72a synthesizes the tip image (puncture needle tip portion emphasized image) generated by the tip detection unit 70a with the ultrasound image of the current frame that is the B-mode image generated by the image processing unit 62 and synthesizes it. An ultrasonic image is generated.
When the tip image generated by the tip detection unit 70a is not represented by the B-mode image signal, the image composition unit 72a performs the same conversion process as the image processing unit 62 on the tip image. After the B-mode image signal, the tip image is superimposed and synthesized on the ultrasonic image of the current frame that is the B-mode image.
In addition, when the ultrasonic image of the current frame, which is a B-mode image generated by the image processing unit 62, is represented by a display image signal that has been scan-converted by DSC, the tip converted into a B-mode image The image also needs to be scan-converted by DSC so as to be represented by the display image signal.
It should be noted that B-mode image signal conversion and scan conversion of signals and data to be processed may be performed at any stage as long as they are the same when combined by the image combining unit 72a. Of course, when the scan conversion is performed by the display control unit 50, it is not necessary to perform the scan conversion in the composite image generation unit 48a.

Each configuration in the present invention is mainly configured by a central processing unit (CPU) and software for causing the CPU to perform various processes, but may be configured by a digital circuit or an analog circuit. These software are stored in an internal memory.
The algorithm of the ultrasonic image generation method according to the present invention is described in a programming language, compiled as necessary, and the ultrasonic image generation method program is stored in a memory (recording medium) to process information in other apparatuses. If executed, the same function as the ultrasonic diagnostic apparatus according to the present invention can be realized. That is, it goes without saying that a program for causing a computer (CPU) to execute the ultrasonic image generation method of the present invention or a recording medium recording the program are included in the embodiment of the present invention. .

  As described above, the ultrasonic diagnostic apparatus and the ultrasonic image generation method according to the present invention have been described with reference to various embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the present invention. Of course, improvements and changes may be made.

DESCRIPTION OF SYMBOLS 10 Ultrasonic diagnostic apparatus 12 Ultrasonic probe 14, 14a Diagnostic apparatus main body 16 Probe main body 18 Communication cable 20 Puncture adapter 34 Ultrasonic transducer 36 Reception signal processing part 38 Transmission drive part 40 Transmission control part 42 Reception control part 44 Probe control part 46 Data storage unit 48, 48a Composite image generation unit 50 Display control unit 52 Display unit 54 Main body control unit 56 Operation unit 58 Storage unit 60 Phased addition unit 62 Image processing unit 64 Image generation unit 66 Time-series frame image storage unit (image storage) Part)
66a Time-series frame echo signal storage unit (echo signal storage unit)
68 Time-series frame difference image generation unit (difference image generation unit)
68a Time-series frame differential echo signal generation unit (differential echo signal generation unit)
70, 70a Puncture needle tip detection unit (tip detection unit)
72, 72a Image composition unit 74 Tip candidate detection unit 76 Tip candidate processing unit 78 Tip candidate storage unit 80 Puncture needle information and condition storage unit (information storage unit)
82 Candidate point extraction processing unit (extraction processing unit)
84 Tip candidate identification processing unit (specific processing unit)

Claims (20)

Transmits ultrasonic waves to the subject into which the puncture device is inserted, receives the reflected waves of the ultrasonic waves from the subject and the puncture device, and generates echo signals of time series frames based on the received reflected waves Ultrasonic transmission / reception means,
Ultrasonic image generation means for generating an ultrasonic image of the subject based on the echo signal generated by the ultrasonic transmission / reception means;
Image display means for displaying the ultrasonic image generated by the ultrasonic image generation means;
Differential echo signal generating means for generating a differential echo signal between time series frames from the echo signals of a plurality of time series frames;
Tip candidate detection means for performing tip detection processing based on the differential echo signal generated by the differential echo signal generation means and detecting one or more tip candidates including the tip of the puncture device;
Tip candidate processing means for generating a tip image in which the tip candidate of the puncture device is subjected to display enhancement processing by performing display enhancement processing on the tip candidate of the puncture device detected by the tip candidate detection means. ,
The image display means displays the tip image of the puncture device subjected to display enhancement processing by the tip candidate processing means so as to be superimposed on the ultrasound image generated by the ultrasound image generation means. Ultrasonic diagnostic equipment.   2. The tip candidate detection unit according to claim 1, wherein the tip candidate detection unit detects the tip candidate of the puncture device based on a luminance difference of the differential echo signal generated by the differential echo signal generation unit as the tip detection process. Ultrasonic diagnostic equipment.   The super tip candidate processing means performs display emphasis processing on the tip candidate of the puncture device detected by the tip candidate detecting means according to whether the difference in luminance of the differential echo signal is positive or negative. Ultrasonic diagnostic equipment.   The tip candidate processing unit generates a color tip image by coloring the tip candidate of the puncture device detected by the tip candidate detection unit or increases the brightness of the tip candidate as the display enhancement processing. The ultrasonic diagnostic apparatus according to claim 1, wherein a high-luminance tip image is generated, or a process of generating a high-luminance color tip image by increasing the luminance after coloring the tip candidates. . The tip candidate detection means further determines the sign of the luminance difference of the differential echo signal,
The tip candidate processing means performs display enhancement processing on the tip candidate of the puncture device detected by the tip candidate detection means according to the sign of the luminance difference of the differential echo signal determined by the tip candidate detection means. The ultrasonic diagnostic apparatus according to claim 1, wherein the hue and brightness are changed. The differential echo signal generation means further generates a differential image based on the generated differential echo signal,
6. The tip candidate detection unit according to claim 1, wherein the tip candidate detection unit performs the tip detection process on the difference image generated by the differential echo signal generation unit and detects the tip candidate of the puncture device. Ultrasonic diagnostic equipment.   The tip candidate detection unit detects the tip candidate of the puncture device by performing a process of extracting a portion having a predetermined luminance difference or more from the difference image generated by the difference echo signal generation unit as the tip detection process. The ultrasonic diagnostic apparatus according to claim 6.   The tip candidate detection means performs gradation processing on the difference image in order to extract a portion having a predetermined luminance difference or more in the difference image generated by the difference echo signal generation means as the tip detection processing. The ultrasonic diagnostic apparatus according to claim 6, wherein a look-up table process using a look-up table is performed to detect the tip candidate of the puncture device.   The ultrasonic diagnostic apparatus according to claim 8, wherein the lookup table used in the lookup table processing by the tip candidate detection unit is adjusted according to at least one of the ultrasound image and the difference image. .   The tip candidate detecting means detects the tip candidate of the puncture device based on a luminance difference of the difference image and a size and density of a region detected by the luminance difference as the tip detection processing. The ultrasonic diagnostic apparatus in any one of 6-9.   The ultrasonic diagnostic apparatus according to claim 6, wherein the tip candidate detection unit performs tip enhancement filter processing on the difference image as the tip detection processing to detect the tip candidate of the puncture device. .   The tip candidate detection means performs a median filter process on the difference image as the tip detection process, or a filter process for emphasizing only a portion where the brightness sum is large by calculating a brightness sum of pixels near a predetermined point, The ultrasonic diagnostic apparatus according to claim 6, wherein the tip candidate of the puncture device is detected.   The tip candidate detecting means searches for a region near the tip candidate of the puncture device detected at a time earlier than the frame displayed on the image display means, and the puncture device from the difference image based on the display frame The ultrasonic diagnostic apparatus according to claim 6, wherein the tip candidate is detected.   The tip candidate detecting means searches for a neighborhood region of a straight line connecting the tip candidates of the puncture device detected at two past times from the frame displayed on the image display means, and the difference based on the display frame The ultrasonic diagnostic apparatus according to claim 6, wherein the tip candidate of the puncture device is detected from an image.   The ultrasonic diagnostic apparatus according to claim 6, wherein the differential echo signal generation unit has a function of adjusting a time difference between the time-series frames for creating the differential image.   The ultrasonic diagnostic apparatus according to any one of claims 6 to 15, wherein the differential echo signal generation unit uses a plurality of frames two or more frames before as a past frame for generating the differential image.   The differential echo signal generation means includes, as preprocessing, signal processing for reducing speckle patterns, signal processing for blurring the puncture device, and / or signal processing for connecting the puncture device to the time-series echo signal. The ultrasonic diagnostic apparatus according to claim 1, wherein the differential echo signal is generated after being performed.   The ultrasonic diagnostic apparatus according to claim 1, wherein the image display unit also displays an image of the tip candidate of the puncture device detected at a past time, and displays a puncture locus of the puncture device. . Further, the tip image on which the tip candidate of the puncture device generated by the tip candidate processing unit is subjected to display emphasis processing is synthesized so as to be superimposed on the ultrasound image generated by the ultrasound image generating unit. An image composition means for generating a composite image,
The ultrasonic diagnostic apparatus according to claim 1, wherein the image display unit displays the combined image combined by the image combining unit. Transmits ultrasonic waves to the subject into which the puncture device is inserted, receives the reflected waves of the ultrasonic waves from the subject and the puncture device, and generates echo signals of time series frames based on the received reflected waves Ultrasonic transmission / reception means,
Ultrasonic image generation means for generating an ultrasonic image of the subject based on the echo signal generated by the ultrasonic transmission / reception means;
Image display means for displaying the ultrasonic image generated by the ultrasonic image generation means;
Difference image generation means for generating a difference image between time series frames from the ultrasound images of a plurality of time series frames generated by the ultrasound image generation means;
Tip candidate detection means for performing tip detection processing based on the difference image generated by the difference image generation means, and detecting one or more tip candidates including the tip of the puncture device;
Tip candidate processing means for generating a tip image in which the tip candidate of the puncture device is subjected to display enhancement processing by performing display enhancement processing on the tip candidate of the puncture device detected by the tip candidate detection means. ,
The image display means displays the tip image of the puncture device subjected to display enhancement processing by the tip candidate processing means so as to be superimposed on the ultrasound image generated by the ultrasound image generation means. Ultrasonic diagnostic equipment.