INFORMATION PROCESSING APPARATUS AND ULTRASOUND SYSTEM

An information processing apparatus configured to process information acquired from a probe including a base having flexibility to bend along a surface of subject's body and a plurality of ultrasound transducers arranged on the base at predetermined intervals. The information processing apparatus includes a controller configured to acquire transmission information, which relates to ultrasound emitted from the ultrasound transducers of the probe whose base is attached to the subject along the surface of the subject's body, and first reception information, which relates to first reflection received by first ultrasound transducers of the ultrasound transducers after the ultrasound is reflected by a first target, and calculate parameters, which relate to a curve of the base, from the transmission information, the first reception information, and the predetermined intervals between the first ultrasound transducers.

TECHNICAL FIELD

The present disclosure relates to an information processing apparatus configured to process information acquired from a probe and an ultrasound system including the information processing apparatus.

BACKGROUND

Using ultrasound systems, condition of a blood vessel or blood flow volume through a blood vessel can be checked. In recent years, development of probes for ultrasound systems that are attachable to a surface of subject's body has been promoted. A probe disclosed in Patent Literature 1, for example, includes a flexible base attachable to the surface of subject's body and a plurality of ultrasound transducers arranged in a matrix on the base.

CITATION LIST

Patent Literature

SUMMARY

Technical Problem

It is preferable that ultrasound systems process information acquired from probes according to a shape of a surface of subject's body to which the probes are attached in order to reduce influence of the shape on the information for a highly accurate diagnosis.

The present disclosure provides an information processing apparatus and an ultrasound system in which information acquired from a probe whose base is attached to a subject along a surface of the subject's body is processed according to a shape of the surface of the subject's body.

Solution to Problem

An information processing apparatus of the present disclosure is configured to process information acquired from a probe including a base having flexibility to bend along a surface of subject's body and a plurality of ultrasound transducers arranged on the base at predetermined intervals. The information processing apparatus includes an information acquisition unit and a calculation unit. The information acquisition unit is configured to acquire transmission information, which relates to ultrasound emitted from the ultrasound transducers of the probe whose base is attached to the subject along the surface of the subject's body, and first reception information, which relates to first reflection received by first ultrasound transducers of the ultrasound transducers after the ultrasound is reflected by a first target. The calculation unit is configured to calculate parameters, which relate to a curve of the base, from the transmission information, the first reception information, and the predetermined intervals between the first ultrasound transducers.

Effects of Invention

In the information processing apparatus, the parameters, which relates to the curve of the base along the surface of the subject's body are calculated. Therefore, using the information processing apparatus, it becomes possible to process the information acquired from the probe according to the curve.

DESCRIPTION OF EMBODIMENTS

In the following, an ultrasound system according to an embodiment of the present disclosure will be described in detail with reference to the drawings. Dimensional ratios in the drawings may be different from actual ratios for the sake of convenience.

Configuration of Ultrasound System

FIG.1is a schematic diagram illustrating an exemplary configuration of an ultrasound system100according to the present embodiment. The ultrasound system100includes, for example, a probe110, an information processing apparatus120, and a cable130. The cable130is configured to convey electrical signals between the probe110and the information processing apparatus120. The cable130may be provided integrally with or detachable from the probe110. The cable130may include a connector and may be connected to the information processing apparatus120by inserting the connector into the information processing apparatus120. The probe110is attachable to a surface of a body of a subject200. Information that has been acquired from the probe110from the subject200is transmitted to the information processing apparatus120through the cable130. The information processing apparatus120may be, for example, a patient monitoring system or a defibrillator configured to acquire vital sign data, such as blood pressure, oxygen saturation, and respiratory rate, or a computer, such as a server and a personal computer.

FIG.2illustrates an example of how the probe110is attached to the subject200. The probe110is attachable to, for example, the surface of the body of the subject200. If the probe100is attached to the neck210of the subject200, information related to a vertebral artery201and a carotid artery202of the subject200can be acquired from the probe110. The carotid artery202is an example of a target.

FIG.3Ais a top view,FIG.3Bis a side view, andFIG.3Cis a perspective view of the probe110. The probe110includes, for example, a base111, a plurality of ultrasound transducers112, and a connector113.

The base111has flexibility to bend along the surface to which the base111is attached. The base111is, for example, a sheetlike member having a quadrangular shape as shown inFIG.3A. The base111is made of resin, such as polyimide resin and silicone.

The ultrasound transducers112are, for example, embedded in or mounted on the base111. Although 64 transducers112arranged in an 8×8 matrix are shown inFIGS.3A to3C, the number and the arrangement of the transducers112are not limited thereto. For example, 96 transducers may be arranged in a 3×32 matrix.

The transducers112may be arranged at regular intervals, and the intervals in the row direction may be equal to those in the column direction. The transducers112shown inFIG.3Aare arranged at regular intervals a in the row and the column directions. The intervals are not limited thereto as long as they are predetermined. The intervals in the row direction may be different from those in the column direction, and the intervals may vary according to the position in the base111.

Each of the transducers112includes, for example, a piezoelectric element and electrodes. The transducers112transmit ultrasound in response to transmission instructions sent from the information processing apparatus120via the cable130. When the transducers112receive the ultrasound (hereinafter, referred to as “reflection”) that has been reflected by blood vessels, bones, organs, or other tissues in the body of the subject200, signals are sent from the transducers112to the information processing apparatus120via the cable130.

A connector113electrically connects the transducers112to the cable130and may be, for example, a wiring board.

FIG.4is an exemplary block diagram of the information processing apparatus120. The information processing apparatus120includes: a central processing unit (CPU)121, or processing circuitry; a read-only memory (ROM)122; a random-access memory (RAM)123; a storage124; a communication interface125; and a display126. They can communicate with each other through a bus127.

The CPU121is configured to control them and to perform a variety of arithmetic processing according to programs stored in the ROM122or the storage124. The ROM122is configured to store programs and data. The RAM123is configured to store programs and data temporarily as a cache.

The storage124is configured to store programs including an operating system and data. For example, a program for exchanging a variety of information with the probe110and a program for analyzing information acquired from the probe110are stored in the storage124. If a machine learning model is used for analyzing the information acquired from the probe110, a trained model or data for training a model may be stored in the storage124.

The communication interface125is a wired or wireless interface for communicating with external devices. The cable130may be connected to the communication interface125.

The display126is, for example, a touch panel configured to receive a variety of input from a user. The display126is an example of an input reception unit. Using the display126, the user can select some of the transducers112to cause them to emit ultrasound. The input from the user is transmitted to the CPU121. The display126may be a combination of an input device and a display. In this case, the input device may be, for example, buttons, a mouse, or a keyboard.

FIG.5illustrates an exemplary functional configuration of the CPU121. The CPU121is configured to perform functionality of an instruction unit1211, an information acquisition unit1212, an image generation unit1213, a calculation unit1214, a compensation unit1215, and an output unit1216by performing processing according to a program loaded from the storage124.

The instruction unit1211is configured to give some of the transducers112selected by the user instructions, through the cable130, to emit ultrasound.

The acquisition unit1212is configured to acquire transmission information and reception information. The transmission information is information relating to ultrasound that has been emitted from some of the transducers112and includes, for example, a position, a drive voltage, a drive frequency, and a gain of the transducers112, a waveform of the ultrasound, and a starting time and duration of the emission. The reception information is information relating to reflection that was reflected by, for example, the carotid artery202and has been received by some of the transducers112and includes, for example, a frequency, a waveform, and an intensity of the reflection, and a time of the reception. When ultrasound has been transmitted from one of the transducers112, its reflection may be received by some or all of the transducers112.

The information acquisition unit1212is configured to acquire the transmission information from the instruction unit1211and to acquire the reception information from the transducers112via the communication interface125. The transmission information may be acquired from the transducers112that have emitted ultrasound. The information acquisition unit1212may further acquire information related to reflection that was reflected by blood vessels (for example, the vertebral artery201) other than the carotid artery202, bones, organs, or other tissues and has been received by the transducers112. That is, the information acquisition unit1212may acquire information related to reflection that was reflected by a plurality of targets and has been received by the transducers112. In this case, it becomes possible to calculate parameters to be described later with high accuracy.

The image generation unit1213is configured to generate image data of the vertebral artery201, the carotid artery202, and the like of the subject200based on the information acquired from the probe110. The transmission information and the reception information may be used for the generation of the image data. The image generation unit1213generates, for example, M-mode, B-mode, color Doppler mode, or pulsed wave Doppler mode images by processing the information acquired from the probe110.

The calculation unit1214is configured to calculate the parameters, which relate to the curve of the base111along the surface of the body of the subject200for reducing a warp of an image due to the curve.

The parameters are calculated from the transmission information, the reception information, and the intervals between the transducers112that has received reflection. The calculation unit1214calculates, for example, angles θ1121, θ1122, and θ1123shown inFIG.6Bas the parameters.

An example of how the angles are calculated by the calculation unit1214will be described with reference toFIGS.6A and6B.FIG.6Ais a perspective view of the probe110attached to the neck210, andFIG.6Bis a cross-sectional view taken along a line B-B shown inFIG.6A. Although the target in the following example is the carotid artery202, the target may be another blood vessel (for example, the vertebral artery201). If ultrasound u is emitted from a transducer1121of the transducers112and is then reflected by a wall of the carotid artery202, reflection r of the ultrasound u will be received by four adjacent transducers1121,1122,1123, and1124of the transducers112.

In this case, the calculation unit1214first calculates a propagation delay, which is a timelag between the emission of the ultrasound u from the ultrasound transducer1121and the reception of the reflection r by each of the transducers1121,1122,1123, and1124. The propagation delay is calculable from the transmission information and the reception information. In the following, t1121denotes the propagation delay of the transducer1121, t1122of the transducer1122, t1123of the transducer1123, and t1124of the transducer1124.

Next, the calculation unit1214calculate a distance between the wall of the carotid artery202and each of the transducers1121to1124from the propagation delays t1121to t1124and the velocity v of the ultrasound u in the body of the subject200. The distance di between the wall of the carotid artery202and the transducer i is calculable from Math. 1. The velocity v is, for example, 1540 m/s.

Next, the calculation unit1214calculates the angles from the distances d1121to d1124. Specifically, the calculation unit1214calculates: the angle θ1121between a straight line connecting the carotid artery202and the transducer1121and a straight line connecting the adjacent transducers1121and1122; the angle θ1122between a straight line connecting the carotid artery202and the transducer1122and a straight line connecting the adjacent transducers1122and1123; and the angle θ1123between a straight line connecting the carotid artery202and the transducer1123and a straight line connecting the adjacent transducer1123and1124. Given that the transducers1121to1124are arranged at the predetermined intervals as shown inFIG.6B, the calculation unit1214finally calculates the angles θ1121to θ1123from Math.2, which is derived from the law of cosines.

It is preferable that the number of the transducers112that have received the reflection r be not less than three when the calculation unit1214calculates the angles. The calculation unit1214may calculate angles between straight lines connecting the vertebral artery201(or another artery) and each of the transducers112.

The calculation unit1214may calculate radii of curvature of the curve as the parameters.

The radius of curvature R1121of the curve formed by the adjacent transducers1121and1122, which is shown inFIG.7B, the radius of curvature R1122of the curve formed by the adjacent transducers1122and1123, and the radius of curvature R1123of the curve formed by the adjacent transducers1123and1124are calculable from Math. 3.

The compensation unit1215is configured to compensate the image data generated by the image generation unit1213based on the parameters.

FIG.8Ais a schematic view illustrating uncompensated imaging regions112rassigned to the transducers112, andFIG.8Bis a schematic view illustrating an image of the carotid artery202generated based on the uncompensated imaging regions112r. In this case, since imaging processing is performed regardless of the curve, the imaging regions112rhaving overlaps shown by dotted lines inFIG.8Aare stretched as if the base111were attached to a flat surface. Therefore, if the base111is attached to a curved surface, the generated image of the carotid artery202is warped as shown inFIG.8B.

FIG.9Ais a schematic view illustrating the imaging regions112rcompensated by the compensation unit1215, andFIG.9Bis a schematic view illustrating an image of the carotid artery202generated based on the compensated imaging regions112r. Based on the parameters calculated by the calculation unit1214, it can be postulated that each of the imaging regions112rhas, for example, a fan shape or an isosceles triangular shape approximately. In this case, the overlaps shown by the dotted lines inFIG.8Aare eliminated, and the generated image reflects more exact shape of the carotid artery202.

The compensation unit1215may compensate, based on the parameters, a cross-sectional area of the carotid artery202that is calculable from its image data.

The output unit1216is configured to output the compensated image data, for example, to the display126. The output unit1216may further output the compensated cross-sectional area of the carotid artery202. The output unit1216may further output information related to blood flow volume through the carotid artery202that is calculable from its color Doppler or pulsed wave Doppler mode images or is calculable from its cross-sectional area and the blood flow velocity.

Processing Performed by Information Processing ApparatusFIG.10is an exemplary flowchart illustrating processing performed by the information processing apparatus120. The information processing apparatus120is configured to acquire information from, for example, the probe110attached to the neck210of the subject200.

First, the information processing apparatus120receives the input of the selection of the transducers112to be caused to emit ultrasound (step S101). For example, the user inputs the selection using the display126, and then the information processing apparatus120receives the selection. The user may view an uncompensated image of the carotid artery202displayed on the display while selecting, for example, the transducers112that are close to the carotid artery202

Next, the information processing apparatus120instructs the selected transducers112to emit ultrasound (step S102). The instructions are sent, for example, via the communication interface125.

Next, the information processing apparatus120acquires the transmission information and the reception information (step S103) and then generates the image data of the carotid artery202based on the information acquired from the probe110(step S104).

Next, the information processing apparatus120calculates the parameters (step S105).

Next, the information processing apparatus120compensates the image data generated in step S104based on the parameters calculated in step S105(step S106). Finally, the information processing apparatus120outputs the image data compensated in step S106(step S107) and ends the processing.

Advantageous Effects of Information Processing Apparatus and Ultrasound System

In the information processing apparatus120and the ultrasound system100of the present embodiment, the image data generated based on the reception information are compensated according to the parameters. Therefore, it becomes possible to reduce the influence of the shape on the image data output from the ultrasound system100for a highly accurate diagnosis.

As for rigid probes, since they do not bend when attached to the surface of subject's body, the shape of the surface to which they are attached have little or no influence on the output information. It is difficult, however, to attach such probes to the subject200.

On the other hand, since the probe110includes the base111, which has flexibility to bend along the surface of the subject200, the user can easily attach the probe110to the surface of the subject200.

The probe110has a problem, however, that the information acquired from the probe110may be affected by the curve. The information processing apparatus120calculates the parameters, which relates to the curve, and compensates the image data based on the parameters to reduce the influence of the shape on the information. Therefore, the ultrasound system100can output exact image data of the vertebral artery201, the carotid artery202, and the like.

FIG.11illustrates an experimental system for demonstrating effectiveness of the compensation. Imaging phantom301and an ultrasound reflector302embedded in the imaging phantom301were used in the experiment. The ultrasound reflector302was made of a metal. The imaging phantom301was mainly made of agar and had a curved surface having a uniform curvature. The probe110was attached to the imaging phantom301along its curved surface. One of the transducers112was caused to emit ultrasound.

In the uncompensated B-mode image ofFIG.12A, the surface corresponding to the bottom of the imaging phantom301is curved due to the curve of the base111. On the other hand, in the compensated B-mode image ofFIGS.12B and13, that surface is straighter than that in theFIG.12A. Therefore, it can be concluded that the compensation reduces the influence of the shape on the B-mode image.

It should be added that the parameters may also be used for other purposes, such as compensation of the blood flow velocity through the carotid artery202. In addition, the compensated image data may be used only for internal processing and do not have to be displayed.

As described above, in the information processing apparatus120and the ultrasound system100of the present embodiment, the information acquired from the probe110is processed according to the parameters. Therefore, it becomes possible to reduce the influence of the curve on the information output from the ultrasound system100for a highly accurate diagnosis.

Since the ultrasound system100enables doctors, nurses, or other persons to attach the probe110to a patient in a short time and to monitor blood flow volume or the like for a long time in a hands-free manner, the ultrasound system100is suitable for emergency medical care. For example, by monitoring the blood flow volume through the carotid artery202, the quality of chest compressions can be continuously checked.

In the following, some modifications of the ultrasound system100will be described. Descriptions of similar configurations will be omitted for the sake of simplicity.

First Modification

FIG.14is a cross-sectional view of a probe110according to a first modification. The probe110according to the first modification further includes an ultrasound reflector114, which is embedded in the base111.

The reflector114has acoustic impedance different from acoustic impedance of the base111and is provided at a predetermined position in the base111. The information processing apparatus120acquires ultrasound that was emitted from the transducers112and has been reflected by the reflector114. The information processing apparatus120calculates the parameters from the transmission information and the reception information. The reflector114is an example of the target.

The reflector114has, for example, a needlelike shape and extends substantially parallel to the base111. Although the reflector114can be made of any material as long as it has acoustic impedance different from that of the base111, it may be made of, for example, metal. The reflector114may be hollow inside. A plurality of reflector114may be provided in the base111.

Similarly to the embodiment described above, using the ultrasound system100including the probe110according to the first modification, it is possible to calculate the parameters to process the reception information acquired from the probe110based on the parameters. Further, by storing information relating to a position of the reflector114in advance in the information processing apparatus120, the information processing apparatus120can easily identify which transducers112are close to the reflector114and can cause some or all of them to emit ultrasound. In this case, since a time required to identify which transducers112are to be caused to emit ultrasound or to identify which transducers emitted ultrasound that has passed through the reflector114can be shortened, it becomes possible to calculate the parameters quickly.

Second Modification

FIG.15illustrates an exemplary functional configuration of a CPU121according to a second modification. The CPU121according to the second modification is configured to perform functionality of a transducer switching unit1218and a transducer specification unit1219in addition to the instruction unit1211, the information acquisition unit1212, the image generation unit1213, the calculation unit1214, the compensation unit1215, and the output unit1216.

The transducer switching unit1218is configured to successively switches the transducers112that are caused to emit ultrasound, for example, in a scanning manner in the row or the column direction of the matrix.

The transducer specification unit1219is configured to identify which transducers112are close to, for example, the carotid artery202. The transducer identification unit1219may identify such transducers112based on whether reflection that has been received by each of the transducers112follows a predetermined pattern or not (for example, a peculiar pattern of amplitude). For example, if one of the transducers112receives reflection following a pattern peculiar to that reflected by the carotid artery202, the transducer specification unit1219determines that that transducer112is close to the carotid artery202. If one of the transducers112receives the reflection that does not follow the pattern, the transducer specification unit1219determines that that transducer112is apart from the carotid artery202. The transducer specification unit1219may identify which transducers112are close to the reflector114, which is shown inFIG.14.

The instruction unit1211according to the second modification is configured to cause some or all of the transducers112that are determined to be close to the carotid artery202by the specification unit1219to emit ultrasound.

FIG.16is an exemplary flowchart illustrating processing performed by the information processing apparatus120including the CPU121according to the second modification.

First, the information processing apparatus120successively switches the transducers112that are caused to emit ultrasound (step S201). Next, the information processing apparatus120identifies which transducers112are close to, for example, the carotid artery202based on whether reflection that has been received by each of the transducers112, which are successively switched in step S201, follows the predetermined pattern or not (step S202). Next, the information processing apparatus120instructs some or all of the transducers112that are identified in step S202to emit ultrasound (step S203).

Next, the information processing apparatus120acquires the transmission information and the reception information (step S204) and generates the image data of the carotid artery202based on the reception information (step S205).

Next, the information processing apparatus120calculates the parameters (step S206) and compensates the image data generated in step S205based on the parameters calculated in step S206(step S207). Finally, the information processing apparatus120outputs the image data compensated in step S207(step S208) and ends the processing.

Similarly to the embodiment described above, using the ultrasound system100including the CPU121according to the second modification, it is possible to calculate the parameters to process the reception information based on the parameters. Further, since it is identified which transducers112are close to, for example, the carotid artery202, it becomes possible to diagnose the subject200or to monitor their vital signs more accurately.

Although some embodiments of the information processing apparatus of the present disclosure have been described, it goes without saying that addition, modification, or omission can be made as appropriate by those skilled in the art within the scope of the technical scope of the present disclosure.

For example, the target is not only the carotid artery202but also may be blood vessels, bones, organs, or other tissues that are anatomically noteworthy.

The probe110may be attached not only to the neck210of the subject200but also to other portions of the subject200. In addition, the probe110does not have to be fixed on the subject200continuously but may be pressed against the subject200intermittently.

The information processing apparatus120does not have to output image data and may output, for example, information related to a cross-sectional area of a blood vessel or blood flow volume through a blood vessel calculated based on the parameters.

The information processing apparatus120may generate compensated image data not only by compensating uncompensated image data based on the parameters but also by directly generating image data based on the parameters.

The parameters are not only angles or radii of curvature but also may be other parameters.

The functionality of the information processing apparatus120may be implemented using circuitry or processing circuitry that includes general-purpose processors, special-purpose processors, integrated circuits, application-specific integrated circuits, conventional circuitry, and/or combinations thereof that are configured or programmed to perform the disclosed functionality. Processors are considered circuitry or processing circuitry as they include transistors and other circuitry therein. In the present disclosure, the circuitry or units are hardware that carry out or are programmed to perform the recited functionality. The hardware may be any hardware disclosed herein or otherwise known that is programmed or configured to carry out the recited functionality. When the hardware is a processor that may be considered a type of circuitry, the circuitry or units are a combination of hardware and software, the software being used to configure the hardware and/or processor. The software may be provided using, for example, a non-transitory computer-readable medium, such as a compact disc read-only memory, or a network, such as the Internet. In this case, the software may be transferred to and stored in a memory or a hard disk drive. The software may be preloaded or to be installed timely.

Division of steps in the flowcharts is merely an example. Each step may be divided into more steps, and some steps may be united.

This application is based on Japanese Patent Application No. 2021-167888 filed on Oct. 13, 2021, the entire contents of which are incorporated herein by reference.