Patent Description:
In the related art, an ultrasound diagnostic apparatus has been known as an apparatus that obtains an image of the inside of a subject. In general, an ultrasound diagnostic apparatus includes an ultrasound probe provided with a transducer array in which a plurality of ultrasound transducers are arranged. The ultrasound probe transmits ultrasound beams from the transducer array toward the inside of the subject in a state of being in contact with a body surface of the subject, and receives ultrasound echoes from the subject by the transducer array. Thereby, an electric signal corresponding to the ultrasound echoes is acquired. Further, the ultrasound diagnostic apparatus generates an ultrasound image for the corresponding portion of the subject by processing the acquired electric signal.

By the way, a technique (so-called echo-guided puncture method) of inserting a so-called puncture needle into a blood vessel of a subject while observing the inside of the subject using an ultrasound diagnostic apparatus is known. In the echo-guided puncture method, an operator usually needs to recognize positions, shapes, and the like of blood vessels included in an ultrasound image by confirming the ultrasound image. However, in order to accurately recognize positions, shapes, and the like of blood vessels, a certain level of proficiency is required. For this reason, a technique of automatically detecting blood vessels included in an ultrasound image and presenting the detected blood vessels to an operator is proposed (refer to, for example, <CIT>). <CIT> relates to a diagnostic ultrasound apparatus, a control method and controller thereof. <CIT> relates to a method and systems for color flow imaging of arteries and veins. <CIT> relates to a ultrasound diagnosis device and a ultrasound diagnosis device control method.

In puncture, an operator needs to accurately determine whether a blood vessel is an artery or a vein based on the ultrasound image. Hereinafter, the determination will be referred to as artery/vein determination.

It is also considered to perform artery/vein determination of a blood vessel by information processing such as image analysis based on the ultrasound image. However, in a case where artery/vein determination is individually performed on the blood vessels, the determination is likely to be erroneous when shapes and the like of arteries and veins are similar.

An object of the technique of the present disclosure is to provide an information processing apparatus, an information processing method, and a program capable of improving accuracy of artery/vein determination of a blood vessel.

According to an aspect of the present disclosure, there is provided an information processing apparatus according to claim <NUM> that performs processing on an ultrasound image, which is generated by transmitting ultrasound beams from a transducer array toward the inside of a living body and receiving ultrasound echoes generated in the living body, the apparatus including: a blood vessel detection unit that detects a blood vessel region including a blood vessel from the ultrasound image; a structure detection unit that detects a structure other than a blood vessel from the ultrasound image; and an artery/vein determination unit that determines whether the blood vessel included in the blood vessel region is an artery or a vein based on a relative positional relationship between the blood vessel region and the structure.

Preferably, the information processing apparatus further includes: a highlight display unit that displays the blood vessel region in the ultrasound image displayed on a display device such that the blood vessel included in the blood vessel region is identified as an artery or a vein.

Preferably, the blood vessel detection unit determines whether the blood vessel included in the blood vessel region is an artery or a vein, in addition to detection of the blood vessel region.

Preferably, the information processing apparatus further includes: a correction unit that corrects a result of artery/vein determination by the blood vessel detection unit based on a result of artery/vein determination by the artery/vein determination unit.

Preferably, the correction unit compares reliability of artery/vein determination by the blood vessel detection unit with reliability of artery/vein determination by the artery/vein determination unit, and selects a determination result having higher reliability.

Preferably, the highlight display unit displays, on the display device, reliability on the determination result selected by the correction unit.

Preferably, the highlight display unit displays, on the display device, a message urging an operator to pay attention in a case where the reliability on the determination result selected by the correction unit is lower than a certain value.

According to another aspect of the present disclosure, there is provided an information processing method according to claim <NUM> for performing processing on an ultrasound image, which is generated by transmitting ultrasound beams from a transducer array toward the inside of a living body and receiving ultrasound echoes generated in the living body, the method including: detecting a blood vessel region including a blood vessel from the ultrasound image; detecting a structure other than a blood vessel from the ultrasound image; and determining whether the blood vessel included in the blood vessel region is an artery or a vein based on a relative positional relationship between the blood vessel region and the structure.

According to still another aspect of the present disclosure, there is provided a program causing a computer to execute a process for performing processing on an ultrasound image according to claim <NUM>, which is generated by transmitting ultrasound beams from a transducer array toward the inside of a living body and receiving ultrasound echoes generated in the living body, the process including: detecting a blood vessel region including a blood vessel from the ultrasound image; detecting a structure other than a blood vessel from the ultrasound image; and determining whether the blood vessel included in the blood vessel region is an artery or a vein based on a relative positional relationship between the blood vessel region and the structure.

According to the technique of the present disclosure, it is possible to provide an information processing apparatus, an information processing method, and a program capable of improving accuracy of artery/vein determination of a blood vessel.

Hereinafter, embodiments according to the technique of the present disclosure will be described with reference to the accompanying drawings. A description of components to be described below is based on a representative embodiment of the present invention. On the other hand, the technique of the present disclosure is not limited to such an embodiment.

<FIG> illustrates an example of a configuration of an ultrasound diagnostic apparatus <NUM> according to the technique of the present disclosure. The ultrasound diagnostic apparatus <NUM> according to the present embodiment includes an ultrasound probe <NUM> and an apparatus main body <NUM>. The ultrasound probe <NUM> is held by an operator and is brought into contact with a surface of a living body to be measured. The ultrasound probe <NUM> transmits and receives ultrasound beams UBs to and from the inside of the living body.

The apparatus main body <NUM> is, for example, a smartphone, a tablet terminal, or the like. By installing a program such as application software in the apparatus main body <NUM>, the apparatus main body <NUM> performs imaging of a signal or the like which is output from the ultrasound probe <NUM>. The ultrasound probe <NUM> and the apparatus main body <NUM> perform wireless communication with each other by, for example, WiFi or Bluetooth (registered trademark). The apparatus main body <NUM> is not limited to a mobile terminal such as a smartphone or a tablet terminal, and may be a personal computer (PC) or the like. The apparatus main body <NUM> is an example of an "information processing apparatus" according to the technique of the present disclosure.

The ultrasound probe <NUM> includes a housing <NUM>. The housing <NUM> is configured by an array housing part 11A and a grip portion 11B. The array housing part 11A houses a transducer array <NUM> (refer to <FIG>). The grip portion 11B is connected to the array housing part 11A, and is gripped by the operator. Here, for the sake of explanation, a direction from the grip portion 11B toward the array housing part 11A is defined as a +Y direction, a width direction of the ultrasound probe <NUM> orthogonal to the Y direction is defined as an X direction, and a direction orthogonal to the X direction and the Y direction (that is, a thickness direction of the ultrasound probe <NUM>) is defined as a Z direction.

An acoustic lens is disposed at an end portion of the array housing part 11A in the +Y direction. A so-called acoustic matching layer (not illustrated) is disposed on the transducer array <NUM>, and the acoustic lens is disposed on the acoustic matching layer. A plurality of transducers included in the transducer array <NUM> are linearly arranged along the X direction. That is, the ultrasound probe <NUM> according to the present embodiment has a linear type, and linearly transmits ultrasound beams UBs. The ultrasound probe <NUM> may have a convex type in which the transducer array <NUM> is disposed in a convex curved shape. In this case, the ultrasound probe <NUM> radially transmits ultrasound beams UBs. Further, the ultrasound probe <NUM> may have a sector type.

In addition, a linear guide marker M extending along the Y direction is attached to an outer peripheral portion of the array housing part 11A. The guide marker M is used as a guide when the operator brings the ultrasound probe <NUM> into contact with a living body.

The apparatus main body <NUM> includes a display device <NUM> for displaying an ultrasound image based on a signal transmitted from the ultrasound probe <NUM>. The display device <NUM> is, for example, a display device such as an organic electro-luminescence (organic EL) display or a liquid crystal display. A touch panel is incorporated in the display device <NUM>. The operator can perform various operations on the apparatus main body <NUM> by using the touch panel.

<FIG> is a diagram illustrating an example of an echo-guided puncture method. As illustrated in <FIG>, the ultrasound probe <NUM> is used when the operator punctures a puncture needle <NUM> into a blood vessel B in a living body <NUM> while checking an ultrasound image displayed on the apparatus main body <NUM>. The living body <NUM> is, for example, an arm of a person. In the ultrasound probe <NUM>, for example, the ultrasound probe <NUM> is brought into contact with the surface of the living body <NUM> such that the width direction (that is, the X direction) of the ultrasound probe <NUM> crosses a traveling direction of the blood vessel B. This procedure is called a short-axis method (or crossing method). A cross section of the blood vessel B is displayed in the ultrasound image. The operator punctures, for example, a vein of one or more blood vessels B displayed in the ultrasound image.

In addition to the blood vessel, an anatomical structure (hereinafter, simply referred to as a structure) is present in the living body <NUM>. The structure is, for example, a biological tissue such as a tendon, a bone, a nerve, or a muscle. The types and features of the structures included in the living body <NUM> differ depending on the parts (arms, legs, abdomen, and the like) of the living body <NUM>.

The apparatus main body <NUM> supports puncturing by the operator by detecting a blood vessel from the ultrasound image, performing artery/vein determination of the blood vessel, and displays a result of the artery/vein determination in the ultrasound image displayed on the display device <NUM>.

<FIG> illustrates an example of a configuration of the ultrasound diagnostic apparatus <NUM>. The ultrasound probe <NUM> includes a transducer array <NUM>, a transmission/reception circuit <NUM>, and a communication unit <NUM>. The transmission/reception circuit <NUM> includes a transmission circuit <NUM> and a reception circuit <NUM>. The transmission circuit <NUM> and the reception circuit <NUM> are respectively connected to the transducer array <NUM>. In addition, the transmission/reception circuit <NUM> transmits and receives signals to and from a processor <NUM> of the apparatus main body <NUM> via the communication unit <NUM>.

The transducer array <NUM> includes a plurality of transducers (not illustrated) which are arranged in one-dimensional manner or two-dimensional manner. Each of these transducers transmits ultrasound beams UBs in accordance with a drive signal supplied from the transmission circuit <NUM> and receives ultrasound echoes from the living body <NUM>. The transducer outputs a signal based on the received ultrasound echoes. The transducer is configured, for example, by forming electrodes at both ends of a piezoelectric body. The piezoelectric body includes a piezoelectric ceramic represented by lead zirconate titanate (PZT), a polymer piezoelectric element represented by poly vinylidene di fluoride (PVDF), a piezoelectric single crystal represented by lead magnesium niobate-lead titanate (PMN-PT), and the like.

The transmission circuit <NUM> includes, for example, a plurality of pulse generators. The transmission circuit <NUM> adjusts a delay amount of a drive signal based on a transmission delay pattern, which is selected according to a control signal transmitted from the processor <NUM> of the apparatus main body <NUM>, and supplies the adjusted delay amount of the drive signal to the plurality of transducers included in the transducer array <NUM>. The delay amount of the drive signal is adjusted by the transmission circuit <NUM> such that the ultrasound waves transmitted from the plurality of transducers form the ultrasound beams UBs. The drive signal is a pulsed or continuous voltage signal. In a case where the drive signal is applied, the transducers transmit pulsed or continuous ultrasound waves by expansion and contraction. By combining the ultrasound waves transmitted from the plurality of transducers, the ultrasound beams UBs as combined waves are formed.

In a case where the ultrasound beams UBs are transmitted into the living body <NUM>, the ultrasound beams UBs are reflected by a part such as a blood vessel B in the living body <NUM>. Thereby, ultrasound echoes are generated, and the ultrasound echoes propagate toward the transducer array <NUM>. The ultrasound echoes which propagate toward the transducer array <NUM> in this way are received by the plurality of transducers included in the transducer array <NUM>. In a case where the ultrasound echoes are received, the transducers generate electric signals by expansion and contraction. The electric signals generated by the transducers are output to the reception circuit <NUM>.

The reception circuit <NUM> generates a sound wave signal by processing the electric signals output from the transducer array <NUM> according to a control signal transmitted from the processor <NUM> of the apparatus main body <NUM>. As illustrated in <FIG> as an example, the reception circuit <NUM> is configured by connecting an amplification unit <NUM>, an analog to digital (A/D) conversion unit <NUM>, and a beam former <NUM> in series.

The amplification unit <NUM> amplifies the signal which is input from each of the plurality of transducers included in the transducer array <NUM>, and transmits the amplified signal to the A/D conversion unit <NUM>. The A/D conversion unit <NUM> converts the signal transmitted from the amplification unit <NUM> into digital reception data, and transmits the converted reception data to the beam former <NUM>. The beam former <NUM> adds a delay to the reception data converted by the A/D conversion unit <NUM> according to a sound velocity or a sound velocity distribution which is set based on a reception delay pattern selected according to a control signal transmitted from the processor <NUM> of the apparatus main body <NUM>. This addition processing is referred to as reception focus processing. By this reception focus processing, a sound wave signal, which is obtained by performing phasing addition on the reception data converted by the A/D conversion unit <NUM> and narrowing down a focus of the ultrasound echo, is acquired.

The apparatus main body <NUM> includes a display device <NUM>, an input device <NUM>, a communication unit <NUM>, a storage device <NUM>, and a processor <NUM>. The input device <NUM> is, for example, a touch panel or the like incorporated in the display device <NUM>. In a case where the apparatus main body <NUM> is a PC or the like, the input device <NUM> may be a keyboard, a mouse, a track ball, a touch pad, or the like. The communication unit <NUM> performs wireless communication with the communication unit <NUM> of the ultrasound probe <NUM>.

The input device <NUM> and the storage device <NUM> are connected to the processor <NUM>. The processor <NUM> and the storage device <NUM> are connected to each other so as to be able to bidirectionally exchange information.

The storage device <NUM> is a device that stores a program <NUM> or the like for operating the ultrasound diagnostic apparatus <NUM>, and is, for example, a flash memory, a hard disc drive (HDD), or a solid state drive (SSD). In a case where the apparatus main body <NUM> is a PC or the like, as the storage device <NUM>, a recording medium such as a flexible disc (FD), a magneto-optical (MO) disc, a magnetic tape, a compact disc (CD), a digital versatile disc (DVD), a secure digital (SD) card, or a Universal Serial Bus (USB) memory, a server, or the like can be used.

The processor <NUM> is, for example, a central processing unit (CPU). The processor <NUM> performs processing based on the program <NUM> in cooperation with a random access memory (RAM) (not illustrated) or the like, and thus the apparatus main body <NUM> functions as a main control unit <NUM>, an image generation unit <NUM>, a display control unit <NUM>, an image analysis unit <NUM>, and a highlight display unit <NUM>.

The processor <NUM> is not limited to the CPU. The processor <NUM> may be configured by a field programmable gate array (FPGA), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a graphics processing unit (GPU), or another integrated circuit (IC), or may be configured by a combination thereof.

The main control unit <NUM> controls each unit of the ultrasound diagnostic apparatus <NUM> based on an input operation by the operator via the input device <NUM>. The main control unit <NUM> transmits the above-described control signal to the ultrasound probe <NUM> via the communication unit <NUM>. The sound wave signal generated by the reception circuit <NUM> is input from the ultrasound probe <NUM> to the processor <NUM> via the communication unit <NUM>.

The image generation unit <NUM> acquires the sound wave signal which is input from the ultrasound probe <NUM> under a control of the main control unit <NUM>, and generates an ultrasound image U based on the acquired sound wave signal. As illustrated in <FIG> as an example, the image generation unit <NUM> is configured by connecting a signal processing unit <NUM>, a digital scan converter (DSC) <NUM>, and an image processing unit <NUM> in series.

The signal processing unit <NUM> performs, on the sound wave signal generated by the reception circuit <NUM>, correction of attenuation due to a distance according to a depth of a reflection position of the ultrasound wave, and then performs envelope detection processing on the corrected sound wave signal. Thereby, a B-mode image signal, which is tomographic image information on a tissue in the subject, is generated.

The DSC <NUM> converts (so-called raster-converts) the B mode image signal generated by the signal processing unit <NUM> into an image signal conforming to a normal television signal scanning method. The image processing unit <NUM> performs various image processing such as gradation processing on the B mode image signal which is input from the DSC <NUM>, and then outputs the B mode image signal to the display control unit <NUM> and the image analysis unit <NUM>. In the following, the B mode image signal obtained by performing image processing by the image processing unit <NUM> is simply referred to as an ultrasound image U.

The transmission/reception circuit <NUM> of the ultrasound probe <NUM> and the image generation unit <NUM> are controlled by the main control unit <NUM> such that the ultrasound image U is periodically generated at a constant frame rate. The transmission/reception circuit <NUM> and the image generation unit <NUM> function as an image acquisition unit that acquires the ultrasound image U.

Under the control of the main control unit <NUM>, the display control unit <NUM> performs predetermined processing on the ultrasound image U generated by the image generation unit <NUM>, and causes the display device <NUM> to display the processed ultrasound image U.

Under the control of the main control unit <NUM>, the image analysis unit <NUM> generates blood vessel information DB by performing image analysis on the ultrasound image U which is input from the image generation unit <NUM>, and outputs the generated blood vessel information DB to the highlight display unit <NUM>. The blood vessel information DB includes, for example, a detection result of a blood vessel region included in the ultrasound image U and a result of artery/vein determination of the detected blood vessel.

The highlight display unit <NUM> controls the display control unit <NUM> based on the blood vessel information DB which is input from the image analysis unit <NUM> under the control of the main control unit <NUM>. Thereby, the blood vessel region is highlighted and displayed in the ultrasound image U displayed on the display device <NUM>. In addition, the highlight display unit <NUM> displays the blood vessel region based on the artery/vein determination result such that the blood vessel included in the blood vessel region can be identified as an artery or a vein.

As illustrated in <FIG> as an example, the image analysis unit <NUM> includes a blood vessel detection unit <NUM>, a structure detection unit <NUM>, an artery/vein determination unit <NUM>, and a correction unit <NUM>. The ultrasound image U generated by the image generation unit <NUM> is input to the blood vessel detection unit <NUM> and the structure detection unit <NUM>.

The blood vessel detection unit <NUM> specifies a blood vessel region by individually detecting each blood vessel included in the ultrasound image U, and performs artery/vein determination of the blood vessel included in the blood vessel region. The blood vessel detection unit <NUM> outputs information including a detection result of a blood vessel region and an artery/vein determination result of the blood vessel region to the correction unit <NUM> and the artery/vein determination unit <NUM>, as blood vessel detection information D1. At least information on the blood vessel region detected by the blood vessel detection unit <NUM> may be input to the artery/vein determination unit <NUM>.

The structure detection unit <NUM> detects a structure region including a structure such as a tendon, a bone, a nerve, or a muscle based on the ultrasound image U, and outputs, as structure detection information D2, information representing the detected structure region to the artery/vein determination unit <NUM>.

The artery/vein determination unit <NUM> performs artery/vein determination of the blood vessel included in the blood vessel region based on an anatomical relative positional relationship between the blood vessel region included in the blood vessel detection information D1 and the structure region included in the structure detection information D2. In other words, the artery/vein determination unit <NUM> sets the structure region as a landmark, and performs artery/vein determination based on a relative positional relationship of the blood vessels when the landmark is set as a reference. The artery/vein determination unit <NUM> outputs, as artery/vein determination information D3, information representing a result of the artery/vein determination to the correction unit <NUM>.

The correction unit <NUM> corrects the artery/vein determination result included in the blood vessel detection information D1 based on the artery/vein determination information D3. The correction unit <NUM> outputs, as the above-described blood vessel information DB, the corrected blood vessel detection information D1 to the highlight display unit <NUM>.

<FIG> illustrates an example of blood vessel detection processing by the blood vessel detection unit <NUM>. The blood vessel detection unit <NUM> performs processing of detecting a blood vessel region Ra including a blood vessel B from the ultrasound image U by using a known algorithm, and performs artery/vein determination of the blood vessel B included in the blood vessel region Ra. In a case where the blood vessel region Ra includes a blood vessel B determined as an artery, the blood vessel region Ra is indicated by a broken line. In addition, in a case where the blood vessel region Ra includes a blood vessel B determined as a vein, the blood vessel region Ra is indicated by a solid line. The blood vessel region Ra illustrated in <FIG> includes a blood vessel B determined as an artery. In a case where the ultrasound image U includes a plurality of blood vessels B, the blood vessel detection unit <NUM> detects the blood vessel region Ra for each of the blood vessels B.

A "label" representing an artery/vein determination result and a "score" representing reliability (that is, certainty) of the artery/vein determination result are associated with the blood vessel region Ra. The label represents whether the blood vessel B included in the blood vessel region Ra is an "artery" or a "vein". The score is a value in a range equal to or larger than <NUM> and equal to or smaller than <NUM>. As the score is closer to <NUM>, the reliability is higher. The blood vessel region Ra associated with the label and the score corresponds to the above-described blood vessel detection information D1.

In the ultrasound image U illustrated in <FIG>, in addition to the blood vessel B, an extensor carpi radialis longus (hereinafter, referred to as ECRL) and an extensor carpi radialis brevis (hereinafter, referred to as ECRB), which are present in a human wrist joint, appear. The ECRL and the ECRB are examples of structures.

In the present embodiment, the blood vessel detection unit <NUM> performs blood vessel detection processing using a blood vessel detection model 71A (refer to <FIG>), which is a trained model generated by machine learning. The blood vessel detection model 71A is, for example, an object detection algorithm using deep learning. As the blood vessel detection model 71A, for example, an object detection model configured by regional CNN (R-CNN), which is a kind of convolutional neural network (CNN), can be used.

The blood vessel detection model 71A detects, as an object, a region including a blood vessel single-body from the ultrasound image U, and determines a label for the detected region. In addition, the blood vessel detection model 71A outputs information representing the detected blood vessel region Ra together with a label and a score.

<FIG> is a diagram illustrating an example of a training phase in which the blood vessel detection model 71A is trained by machine learning. The blood vessel detection model 71A performs training using training data TD1. The training data TD1 includes a plurality of training images P associated with correct answer labels L. The training image P included in the training data TD1 is a sample image of a blood vessel single-body (artery and vein). The training data TD1 includes various training images P in which blood vessels have different shapes, sizes, and the like.

In the training phase, the training image P is input to the blood vessel detection model 71A. The blood vessel detection model 71A outputs a determination result A of the training image P. Loss calculation is performed using a loss function based on the determination result A and the correct answer label L. In addition, update setting of various coefficients of the blood vessel detection model 71A is performed according to a result of the loss calculation, and the blood vessel detection model 71A is updated according to the update setting.

In the training phase, a series of processing, which includes inputting of the training image P to the blood vessel detection model 71A, outputting of the determination result A from the blood vessel detection model 71A, the loss calculation, the update setting, and updating of the blood vessel detection model 71A, is repeatedly performed. The repetition of the series of processing is ended in a case where detection accuracy reaches a predetermined setting level. The blood vessel detection model 71A of which the detection accuracy reaches the setting level is stored in the storage device <NUM>, and then is used by the blood vessel detection unit <NUM> in the blood vessel detection processing which is in an operation phase.

<FIG> illustrates an example of structure detection processing by the structure detection unit <NUM>. The structure detection unit <NUM> performs processing of detecting a structure region Rb including a structure from the ultrasound image U by using a known algorithm.

In the present embodiment, the structure detection unit <NUM> performs structure detection processing using a structure detection model 72A (refer to <FIG>), which is a trained model generated by machine learning. The structure detection model 72A is, for example, an object detection algorithm using deep learning. As the structure detection model 72A, for example, an object detection model configured by R-CNN, which is a kind of CNN, can be used.

The structure detection unit <NUM> detects, as an object, a structure region Rb including a structure from the ultrasound image U. The information representing the structure region Rb corresponds to the structure detection information D2 described above. In the example illustrated in <FIG>, the structure detection unit <NUM> detects, as the structure region Rb, a region including the ECRL and the ECRB. The structure detection unit <NUM> may individually detect, as the structure regions Rb, the region including the ECRL and the region including the ECRB.

<FIG> is a diagram illustrating an example of a training phase in which the structure detection model 72A is trained by machine learning. The structure detection model 72A performs training using training data TD2. The training data TD2 includes a plurality of training images P associated with correct answer labels L. The training image P included in the training data TD2 is a sample image of a structure. The training data TD2 includes training images P of various structures having different types (such as tendons, bones, nerves, or muscles), numbers, shapes, sizes, textures, and the like of biological tissues.

In the training phase, the training image P is input to the structure detection model 72A. The structure detection model 72A outputs a determination result A of the training image P. Loss calculation is performed using a loss function based on the determination result A and the correct answer label L. In addition, update setting of various coefficients of the structure detection model 72A is performed according to a result of the loss calculation, and the structure detection model 72A is updated according to the update setting.

In the training phase, a series of processing, which includes inputting of the training image P to the structure detection model 72A, outputting of the determination result A from the structure detection model 72A, the loss calculation, the update setting, and updating of the structure detection model 72A, is repeatedly performed. The repetition of the series of processing is ended in a case where detection accuracy reaches a predetermined setting level. The structure detection model 72A of which the detection accuracy reaches the setting level is stored in the storage device <NUM>, and then is used by the structure detection unit <NUM> in the structure detection processing which is in an operation phase.

<FIG> illustrates an example of artery/vein determination processing by the artery/vein determination unit <NUM>. The artery/vein determination unit <NUM> performs artery/vein determination of the blood vessel B included in the blood vessel region Ra based on an anatomical relative positional relationship between the blood vessel region Ra included in the blood vessel detection information D1 and the structure region Rb included in the structure detection information D2. The artery/vein determination unit <NUM> obtains, as a label for the blood vessel B, a score for each of "artery" and "vein", and selects the label having a higher score. The artery/vein determination unit <NUM> generates artery/vein determination information D3 by obtaining the label and the score for the blood vessel B included in the blood vessel region Ra.

The artery/vein determination unit <NUM> performs artery/vein determination processing by using, for example, a trained model obtained by performing training using training data representing an anatomical relative positional relationship between the blood vessel region Ra and the structure region Rb. The artery/vein determination unit <NUM> may perform artery/vein determination using known data representing an anatomical relative positional relationship.

The blood vessel region Ra illustrated in <FIG> is located on radialis (that is, a radius side) with respect to the structure region Rb including the ECRL and the ECRB, and thus the blood vessel B included in the blood vessel region Ra is determined as a vein (specifically, a cephalic vein). In this way, artery/vein determination of the blood vessel is performed using the anatomical relative positional relationship between the blood vessel and the structure, and thus accuracy of the artery/vein determination is improved.

<FIG> illustrates an example of correction processing performed by the correction unit <NUM>. The correction unit <NUM> compares, for the corresponding blood vessel B, the score included in the artery/vein determination information D3 with the score included in the blood vessel detection information D1, and selects the label having a higher score. For example, in the example illustrated in <FIG>, for the blood vessel B, the score (<NUM>) included in the artery/vein determination information D3 is higher than the score (<NUM>) included in the blood vessel detection information D1. Therefore, the correction unit <NUM> selects, as the label of the blood vessel B, the label (vein) included in the artery/vein determination information D3 instead of the label (artery) included in the blood vessel detection information D1.

In this way, in a case where the score included in the artery/vein determination information D3 is higher than the score included in the blood vessel detection information D1, the label included in the blood vessel detection information D1 is corrected.

The correction unit <NUM> outputs, as the above-described blood vessel information DB, the corrected blood vessel detection information D1 in which the label is corrected to the highlight display unit <NUM>. The blood vessel information DB includes position information of the blood vessel region Ra in the ultrasound image U, and the label and the score for the blood vessel region Ra.

<FIG> illustrates an example of highlight display processing by the highlight display unit <NUM>. The highlight display unit <NUM> displays the blood vessel region Ra in the ultrasound image U displayed on the display device <NUM> of the apparatus main body <NUM> based on the blood vessel information DB by using a rectangular frame. In addition, the highlight display unit <NUM> displays the blood vessel region Ra based on the artery/vein determination result such that the blood vessel included in the blood vessel region Ra can be identified as an artery or a vein. In the example illustrated in <FIG>, the blood vessel region Ra including a vein is indicated by a solid line, and the blood vessel region Ra including an artery is indicated by a broken line. The highlight display unit <NUM> may display the blood vessel region Ra such that the blood vessel region Ra can be identified according to a thickness of a line, a color of a line, brightness of a line, or the like without being limited to the line type.

Next, an example of an operation of the ultrasound diagnostic apparatus <NUM> will be described with reference to a flowchart illustrated in <FIG>. First, the main control unit <NUM> determines whether or not a start operation is performed by the operator using the input device <NUM> or the like (step S10). In a case where it is determined that a start operation is performed (YES in step S10), the main control unit <NUM> generates the ultrasound image U by operating the transmission/reception circuit <NUM> of the ultrasound probe <NUM> and the image generation unit <NUM> (step S <NUM>). The generated ultrasound image U is displayed on the display device <NUM> by the display control unit <NUM>.

At this time, as illustrated in <FIG>, the operator brings the ultrasound probe <NUM> into contact with the surface of the living body <NUM>. The ultrasound beams UBs are transmitted from the transducer array <NUM> into the living body <NUM> according to the drive signal which is input from the transmission circuit <NUM>. The ultrasound echo from the living body <NUM> is received by the transducer array <NUM>, and the received signal is output to the reception circuit <NUM>. The received signal which is received by the reception circuit <NUM> is processed via the amplification unit <NUM>, the A/D conversion unit <NUM>, and the beam former <NUM>, and thus a sound wave signal is generated. The sound wave signal is output to the apparatus main body <NUM> via the communication unit <NUM>.

The apparatus main body <NUM> receives the sound wave signal which is output from the ultrasound probe <NUM> via the communication unit <NUM>. The sound wave signal which is received by the apparatus main body <NUM> is input to the image generation unit <NUM>. In the image generation unit <NUM>, a B-mode image signal is generated by performing envelope detection processing on the sound wave signal by the signal processing unit <NUM>, and the B-mode image signal is subjected to the DSC <NUM> and the image processing unit <NUM>. Thus, an ultrasound image U is output to the display control unit <NUM>. Further, the ultrasound image U is output to the image analysis unit <NUM>.

In the image analysis unit <NUM>, the blood vessel detection processing (refer to <FIG>) is performed by the blood vessel detection unit <NUM> (step S12). The blood vessel detection information D1 generated by the blood vessel detection processing is output to the correction unit <NUM> and the artery/vein determination unit <NUM>.

In addition, step S13 is performed in parallel with step S12. In step S13, the structure detection processing (refer to <FIG>) is performed by the structure detection unit <NUM>. The structure detection information D2 generated by the structure detection processing is output to the artery/vein determination unit <NUM>. In step S14, the artery/vein determination processing (refer to <FIG>) is performed by the artery/vein determination unit <NUM>. The artery/vein determination information D3 generated by the artery/vein determination processing is output to the correction unit <NUM>.

Next, the correction processing (refer to <FIG>) is performed by the correction unit <NUM> (step S15). In the correction processing, the label for the blood vessel region Ra included in the blood vessel detection information D1 is corrected based on the artery/vein determination information D3. As a result of the correction processing, the blood vessel information DB is output to the highlight display unit <NUM>.

In addition, the highlight display processing (refer to <FIG>) is performed by the highlight display unit <NUM> (step S16). By the highlight display processing, the blood vessel region Ra is highlighted and displayed in the ultrasound image U displayed on the display device <NUM>. In addition, the blood vessel region Ra is displayed such that the blood vessel included in the blood vessel region Ra can be identified as an artery or a vein. In this way, by performing highlight display, the operator can accurately recognize the position of the blood vessel in the ultrasound image U, and can accurately recognize whether the blood vessel is an artery or a vein.

Next, the main control unit <NUM> determines whether or not an end operation is performed by the operator using the input device <NUM> or the like (step S17). In a case where it is determined that an end operation is not performed (NO in step S17), the main control unit <NUM> returns the processing to step S11. Thereby, a new ultrasound image U is generated. On the other hand, in a case where it is determined that an end operation is performed (YES in step S17), the main control unit <NUM> ends the operation of the ultrasound diagnostic apparatus <NUM>.

In the related art, a blood vessel is detected by blood vessel detection processing, and artery/vein determination is individually performed on the detected blood vessel. In such a method, an error often occurs in the artery/vein determination of the blood vessel, and a result of the artery/vein determination may change for each frame. In a case where the operator attempts to perform puncture based on the result of the artery/vein determination, the blood vessel to be punctured may be mistaken.

On the other hand, according to the technique of the present disclosure, artery/vein determination of the blood vessel is performed using the anatomical relative positional relationship between the blood vessel and the structure which are detected from the ultrasound image, and thus accuracy of the artery/vein determination is improved. Thereby, the operator can accurately recognize the blood vessel (for example, a vein) to be punctured.

Next, examples of blood vessel detection processing, structure detection processing, artery/vein determination processing, correction processing, and highlight display processing for an ultrasound image U different from the ultrasound image U illustrated in <FIG> will be described with reference to <FIG>.

As illustrated in <FIG>, two blood vessels B1 and B2 appear in the ultrasound image U according to the present example. In addition, in the ultrasound image U, an abductor pollicis longus (hereinafter, referred to as APL) and a radius styloid process (hereinafter, simply referred to as an apophysis) appear. The APL and the apophysis are examples of structures.

In the blood vessel detection processing, the blood vessel detection unit <NUM> detects, as the blood vessel region Ra, each of the region including the blood vessel B1 and the region including the blood vessel B2 in the ultrasound image U, and associates a label and a score with each of the blood vessel regions Ra. The two blood vessel regions Ra associated with the label and the score correspond to the above-described blood vessel detection information D1. In the present example, the labels of the blood vessels B1 and B2 are both determined as a "vein".

As illustrated in <FIG>, in the structure detection processing, the structure detection unit <NUM> detects, as the structure region Rb, each of the region including the APL and the region including the apophysis in the ultrasound image U. The information representing the two structure region Rb corresponds to the structure detection information D2 described above.

As illustrated in <FIG>, in the artery/vein determination processing, the artery/vein determination unit <NUM> performs artery/vein determination on each of the two blood vessel regions Ra based on an anatomical relative positional relationship between the blood vessel region and the two structure regions Rb. The artery/vein determination unit <NUM> generates artery/vein determination information D3 by obtaining the label and the score for each of the blood vessels B1 and B2.

As illustrated in <FIG>, in the correction processing, the correction unit <NUM> compares the score included in the artery/vein determination information D3 with the score included in the blood vessel detection information D1 for each of the blood vessels B1 and B2, and selects the label having a higher score. In the present example, for both the blood vessels B1 and B2, the score included in the artery/vein determination information D3 is higher than the score included in the blood vessel detection information D1, and thus the label included in the artery/vein determination information D3 is selected. In the present example, in the labels of the blood vessels B1 and B2 included in the blood vessel detection information D1, the label of the blood vessel B <NUM> is corrected from "vein" to "artery".

As illustrated in <FIG>, in the highlight display processing, the blood vessel region Ra is highlighted and displayed in the ultrasound image U based on the corrected label. In the present example, the blood vessel region Ra including the blood vessel B1 determined as "artery" is indicated by a broken line, and the blood vessel region Ra including the blood vessel B2 determined as "vein" is indicated by a solid line.

Hereinafter, various modification examples of the ultrasound diagnostic apparatus <NUM> according to the first embodiment will be described.

In the first embodiment, the artery/vein determination unit <NUM> obtains, as the label for the blood vessel B, a score for each of "artery" and "vein" in the artery/vein determination processing (refer to <FIG>), and selects the label having a higher score. Instead, for example, as illustrated in <FIG>, a threshold value for a score may be set, and a label having a score equal to or higher than the threshold value may be selected.

In addition, for example, as illustrated in <FIG>, in a case where the score is obtained for each of "artery" and "vein" as the label for the blood vessel B, both scores may be lower than the threshold value. This corresponds to low accuracy of the artery/vein determination based on the relative positional relationship between the blood vessel and the structure. In this case, it is difficult to perform label determination (that is, artery/vein determination). Thus, the artery/vein determination unit <NUM> may stop artery/vein determination. In such a case where it is difficult to perform artery/vein determination, the highlight display unit <NUM> may display the blood vessel region Ra in the ultrasound image U without distinguishing whether the blood vessel region Ra is an "artery" or a "vein". In this case, the highlight display unit <NUM> may simply display the blood vessel region Ra as a "blood vessel".

In addition, in a case where a structure is not found from the ultrasound image U by the structure detection processing, the highlight display unit <NUM> may display the blood vessel region Ra in the ultrasound image U without distinguishing whether the blood vessel region Ra is an "artery" or a "vein".

In addition, in a case where a structure is not found from the ultrasound image U by the structure detection processing, or in a case where accuracy of the artery/vein determination based on the relative positional relationship between the blood vessel and the structure is low, the highlight display unit <NUM> may perform highlight display based on the label included in the blood vessel detection information D1.

In addition, as illustrated in <FIG>, for example, the highlight display unit <NUM> may display the score for the label selected by the correction unit <NUM> (that is, reliability for the determination result selected by the correction unit <NUM>) in association with the blood vessel region Ra. Thereby, the operator can recognize the reliability of the artery/vein determination for each blood vessel.

In addition, as illustrated in <FIG>, for example, the highlight display unit <NUM> may display a message urging the operator to pay attention in a case where the score for the label selected by the correction unit <NUM> (that is, reliability for the determination result selected by the correction unit <NUM>) is lower than a certain value. Thereby, the operator can reliably recognize that reliability of the artery/vein determination is low and caution is required in the puncture.

In addition, the artery/vein determination unit <NUM> may change the criterion for the artery/vein determination according to a type or the like of the structure detected by the structure detection unit <NUM>. This is because, for example, in a case where the structure has anatomically typical features in relation to the blood vessel, there is a high possibility that the determination result is correct even when the score of the artery/vein determination is low. The artery/vein determination unit <NUM> changes the threshold value for the score (refer to <FIG>) according to, for example, a type or the like of the structure. Specifically, in a case where the structure has anatomically typical features in relation to the blood vessel, the threshold value is set to be lower than the threshold value in a case where the structure does not have anatomically typical features. The criterion for the artery/vein determination is not limited to the threshold value for the score, and may be changed by changing the algorithm for the artery/vein determination.

In addition, in the first embodiment, the labels for the blood vessel are two types of "artery" and "vein". On the other hand, the labels may be further subdivided. For example, "vein" is subdivided into a "cephalic vein", a "basilic vein", and the like. Thereby, the artery/vein determination unit <NUM> can specify the type of the blood vessel in addition to the artery/vein determination. In this case, the highlight display unit <NUM> may display the type of the blood vessel in association with the blood vessel region Ra.

In addition, in the first embodiment, the blood vessel detection unit <NUM> performs the artery/vein determination of the blood vessel. On the other hand, the blood vessel detection unit <NUM> may perform only detection of the blood vessel region Ra without performing the artery/vein determination. In this case, the correction unit <NUM> that corrects the result of the artery/vein determination by the blood vessel detection unit <NUM> is not required.

In addition, in the first embodiment, the blood vessel detection unit <NUM> and the structure detection unit <NUM> are respectively configured by individual object detection models. On the other hand, the blood vessel detection unit <NUM> and the structure detection unit <NUM> can be configured by one object detection model. In this case, the object detection model may be trained using training data including a training image of the blood vessel single-body and a training image of the structure. In addition, the blood vessel detection unit <NUM>, the structure detection unit <NUM>, and the artery/vein determination unit <NUM> can be configured by one object detection model. Further, the blood vessel detection unit <NUM>, the structure detection unit <NUM>, the artery/vein determination unit <NUM>, and the correction unit <NUM> can be configured by one object detection model.

In addition, in the first embodiment, the blood vessel detection unit <NUM> and the structure detection unit <NUM> are configured by an object detection model of a CNN. On the other hand, the object detection model is not limited to the CNN, and segmentation or another general detection model may be used.

In addition, the object detection model including the blood vessel detection unit <NUM> and the structure detection unit <NUM> may be configured by an identifier that identifies an object based on an image feature amount such as AdaBoost or a support vector machine (SVM). In this case, after the training image is converted into a feature amount vector, the identifier may be trained based on the feature amount vector.

In addition, the blood vessel detection unit <NUM> and the structure detection unit <NUM> are not limited to the object detection model by machine learning, and may perform object detection by template matching. In this case, the blood vessel detection unit <NUM> stores, as a template, typical pattern data of a blood vessel single-body in advance, and calculates a similarity to the pattern data while searching for the ultrasound images U by using the template. In addition, the blood vessel detection unit <NUM> specifies, as a blood vessel region Ra, a portion where the similarity is equal to or higher than a certain level and is maximized. Further, the structure detection unit <NUM> stores, as a template, typical pattern data of a structure in advance, and calculates a similarity to the pattern data while searching for the ultrasound images U by using the template. In addition, the structure detection unit <NUM> specifies, as a blood vessel region Ra, a portion where the similarity is equal to or higher than a certain level and is maximized. The template may be a part of an actual ultrasound image, or may be an image drawn by modeling a blood vessel or a structure.

Further, in order to calculate the similarity, in addition to simple template matching, for example, a machine learning method, which is described in <NPL>), or a general image recognition method using deep learning, which is described in <NPL>), can be used.

In the first embodiment, the ultrasound probe <NUM> and the apparatus main body <NUM> are connected by wireless communication. Instead, the ultrasound probe <NUM> and the apparatus main body <NUM> may be connected by wire.

Further, in the first embodiment, the image generation unit <NUM> that generates an ultrasound image U based on the sound wave signal is provided in the apparatus main body <NUM>. Instead, the image generation unit <NUM> may be provided in the ultrasound probe <NUM>. In this case, the ultrasound probe <NUM> generates an ultrasound image U and outputs the ultrasound image U to the apparatus main body <NUM>. The processor <NUM> of the apparatus main body <NUM> performs image analysis or the like based on the ultrasound image U which is input from the ultrasound probe <NUM>.

Further, in the first embodiment, the display device <NUM>, the input device <NUM>, and the ultrasound probe <NUM> are directly connected to the processor <NUM>. On the other hand, the display device <NUM>, the input device <NUM>, and the ultrasound probe <NUM> may be indirectly connected to the processor <NUM> via a network.

As an example, in the ultrasound diagnostic apparatus 2A illustrated in <FIG>, the display device <NUM>, the input device <NUM>, and the ultrasound probe 10A are connected to the apparatus main body 20A via a network NW. The apparatus main body 20A is obtained by removing the display device <NUM> and the input device <NUM> from the apparatus main body <NUM> according to the first embodiment and adding the transmission/reception circuit <NUM>, and is configured by the transmission/reception circuit <NUM>, the storage device <NUM>, and the processor <NUM>. The ultrasound probe 10A is obtained by removing the transmission/reception circuit <NUM> from the ultrasound probe <NUM> according to the first embodiment.

In this way, in the ultrasound diagnostic apparatus 2A, the display device <NUM>, the input device <NUM>, and the ultrasound probe 10A are connected to the apparatus main body 20A via the network NW, and thus the apparatus main body 20A can be used as a so-called remote server. Thereby, for example, the operator can prepare the display device <NUM>, the input device <NUM>, and the ultrasound probe 10A at the operator's hand, and thus convenience is improved. In addition, in a case where the display device <NUM> and the input device <NUM> are configured by a mobile terminal such as a smartphone or a tablet terminal, convenience is further improved.

As another example, in the ultrasound diagnostic apparatus 2B illustrated in <FIG>, the display device <NUM> and the input device <NUM> are provided in the apparatus main body 20B, and the ultrasound probe 10A is connected to the apparatus main body 20B via the network NW. In this case, the apparatus main body 20B may be configured by a remote server. In addition, the apparatus main body 20B can be configured by a mobile terminal such as a smartphone or a tablet terminal.

In the first embodiment, for example, the following various processors may be used as a hardware structure of processing units that perform various processing, such as the main control unit <NUM>, the image generation unit <NUM>, the display control unit <NUM>, the image analysis unit <NUM>, and the highlight display unit <NUM>. The various processors include, as described above, a CPU which is a general-purpose processor that functions as various processing units by executing software (program <NUM>), and a dedicated electric circuit which is a processor having a circuit configuration specifically designed to execute specific processing, such as a programmable logic device (PLD) or an ASIC that is a processor of which the circuit configuration may be changed after manufacturing such as a field programmable gate array (FPGA).

One processing unit may be configured by one of these various processors, or may be configured by a combination of two or more processors having the same type or different types (for example, a combination of a plurality of FPGAs and/or a combination of a CPU and an FPGA). Further, the plurality of processing units may be configured by one processor.

As an example in which the plurality of processing units are configured by one processor, firstly, as represented by a computer such as a client and a server, a form in which one processor is configured by a combination of one or more CPUs and software and the processor functions as the plurality of processing units may be adopted. Secondly, as represented by a system on chip (SoC) or the like, a form in which a processor that realizes the function of the entire system including the plurality of processing units by one IC chip is used may be adopted. As described above, the various processing units are configured by using one or more various processors as a hardware structure.

Further, as the hardware structure of the various processors, more specifically, an electric circuit (circuitry) in which circuit elements such as semiconductor elements are combined may be used.

The technique of the present disclosure can also appropriately combine the various embodiments and/or the various modification examples. In addition, the technique of the present disclosure is not limited to the embodiments, and various configurations may be adopted without departing from the scope of the present disclosure.

The described contents and the illustrated contents are detailed explanations of a part according to the technique of the present disclosure, and are merely examples of the technique of the present disclosure. For example, the descriptions related to the configuration, the function, the operation, and the effect are descriptions related to examples of a configuration, a function, an operation, and an effect of a part according to the technique of the present disclosure. Therefore, it goes without saying that, in the described contents and illustrated contents, unnecessary parts may be deleted, new components may be added, or replacements may be made without departing from the spirit of the technique of the present disclosure. Further, in order to avoid complications and facilitate understanding of the part according to the technique of the present disclosure, in the described contents and illustrated contents, descriptions of technical knowledge and the like that do not require particular explanations to enable implementation of the technique of the present disclosure are omitted.

Claim 1:
An information processing apparatus that performs processing on an ultrasound image (U), which is generated by transmitting ultrasound beams (UB) from a transducer array (<NUM>) toward the inside of a living body and receiving ultrasound echoes generated in the living body, the apparatus comprising:
a blood vessel detection unit (<NUM>) configured to detect a blood vessel region including a blood vessel (B, B1, B2) from the ultrasound image (U);
a structure detection unit (<NUM>) configured to detect a structure other than a blood vessel from the ultrasound image (U);
characterized by
an artery/vein determination unit (<NUM>) configured to determine whether the blood vessel included in the blood vessel region (Ra) is an artery or a vein based on a relative positional relationship between the blood vessel region (Ra) and the structure.