ULTRASOUND DIAGNOSTIC APPARATUS AND METHOD OF CONTROLLING ULTRASOUND DIAGNOSTIC APPARATUS

An ultrasound diagnostic apparatus includes an ultrasound probe (2) that scans a subject with an ultrasound beam, an image acquisition unit (8) that acquires ultrasound images of a plurality of frames corresponding to a plurality of different tomographic planes in the subject using the ultrasound probe (2), an image memory (9) that keeps the acquired ultrasound images of the plurality of frames, a bladder extraction unit (10) that extracts a bladder region from each of the ultrasound images of the plurality of frames, a feature value calculation unit (11) that calculates a feature value regarding the bladder region extracted in each of the ultrasound images of the plurality of frames, and a scanning success/failure determination unit (12) that analyzes change in feature value between frames continuous in time series and determines whether or not scanning of a bladder of the subject with an ultrasound beam is successful.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an ultrasound diagnostic apparatus and a method of controlling an ultrasound diagnostic apparatus, and in particular, to an ultrasound diagnostic apparatus and a method of controlling an ultrasound diagnostic apparatus that measure a urine volume in a bladder of a subject.

2. Description of the Related Art

Hitherto, in a medical field, an ultrasound diagnostic apparatus using an ultrasound image has come into practical use. In general, this kind of ultrasound diagnostic apparatus has an ultrasound probe that incorporates a transducer array, and an apparatus body connected to the ultrasound probe. The ultrasound probe transmits ultrasonic waves toward a subject and receives ultrasound echoes from the subject, and the apparatus body electrically processes reception signals to generate an ultrasound image.

A bladder of the subject is observed using such an ultrasound diagnostic apparatus, and a urine volume in the observed bladder is measured. In general, the urine volume in the bladder of the subject is substantially equal to the volume of the bladder of the subject, and thus, the volume of the bladder of the subject is measured as the urine volume. Although the volume of the bladder of the subject can be calculated, for example, using the maximum diameter in a longitudinal direction, the maximum diameter in the lateral direction, and the maximum diameter in a depth direction of the bladder while regarding the bladder as an ellipsoid, normally, to obtain the maximum diameters of the bladder in the longitudinal direction, the lateral direction, and the depth direction, the user needs to move the ultrasound probe to observe a tomographic image of the bladder in which a diameter of the bladder in the longitudinal direction is maximized and a tomographic image of the bladder in which a diameter of the bladder in the lateral direction is maximized, and to manually measure the diameter of the bladder.

Accordingly, to save labor of the user to manually measure the diameter of the bladder on the tomographic image, as disclosed in JP2017-109074A, an ultrasound diagnostic apparatus that automatically extracts a bladder region in an ultrasound image in acquired ultrasound images of a plurality of frames, measures a diameter of the extracted bladder region, and measures the volume of a bladder of a subject based on the measured diameter of the bladder region.

SUMMARY OF THE INVENTION

However, in the ultrasound diagnostic apparatus of JP2017-109074A, for example, in a case where the bladder region is incorrectly extracted for the reason that an ultrasound image where the bladder of the subject is not clearly shown is included in the acquired ultrasound images of the plurality of frames, or the like, there is a problem regarding measurement accuracy of the urine volume, such as a case where an incorrect value is calculated on the volume of the bladder, that is, the urine volume.

The invention has been accomplished to solve the problem in the related art, and an object of the invention is to provide an ultrasound diagnostic apparatus and a method of controlling an ultrasound diagnostic apparatus capable of measuring a urine volume in a bladder of a subject with excellent accuracy.

To achieve the above-described object, an ultrasound diagnostic apparatus according to an aspect of the invention comprises an ultrasound probe that is brought into contact with a subject and scans the subject with an ultrasound beam, an image acquisition unit that acquires ultrasound images of a plurality of frames corresponding to a plurality of different tomographic planes in the subject using the ultrasound probe, an image memory that keeps the ultrasound images of the plurality of frames acquired by the image acquisition unit, a bladder extraction unit that extracts a bladder region from each of the ultrasound images of the plurality of frames, a feature value calculation unit that calculates a feature value regarding the bladder region extracted by the bladder extraction unit in each of the ultrasound images of the plurality of frames, and a scanning success/failure determination unit that analyzes change in the feature value calculated by the feature value calculation unit between frames continuous in time series and determines whether or not scanning of a bladder of the subject with the ultrasound beam is successful based on an analysis result.

It is preferable that the ultrasound images of the plurality of frames are ultrasound images that are acquired by the image acquisition unit while changing a tilt angle of the ultrasound probe over a given angle range with respect to the subject while a contact position of the ultrasound probe with the subject is fixed.

It is preferable that the ultrasound diagnostic apparatus further comprises a maximum diameter measurement unit that measures a maximum diameter of the bladder region using the ultrasound images of the plurality of frames in a case where the scanning success/failure determination unit determines that the scanning with the ultrasound beam is successful.

The ultrasound images of the plurality of frames may be ultrasound images that are acquired by the image acquisition unit in a case where a plurality of times of scanning of the bladder of the subject with the ultrasound beam are performed.

In this case, the scanning success/failure determination unit may determine whether or not each of the plurality of times of scanning with the ultrasound beam is successful.

It is preferable that the ultrasound diagnostic apparatus further comprises a maximum diameter measurement unit that measures a maximum diameter of the bladder region using only ultrasound images of a plurality of frames acquired by scanning with the ultrasound beam determined to be successful by the scanning success/failure determination unit among the plurality of times of scanning with the ultrasound beam.

It is preferable that the feature value is an area or a diameter of the bladder region extracted by the bladder extraction unit in the ultrasound image.

In this case, the scanning success/failure determination unit may determine whether or not the scanning of the bladder of the subject with the ultrasound beam is successful by analyzing continuity of change in the feature value between frames continuous in time series.

More specifically, the scanning success/failure determination unit may determine that the scanning with the ultrasound beam is successful in a case where a difference value of the feature values between any frames continuous in time series in the ultrasound images of the plurality of frames is smaller than a given threshold value, and may determine that the scanning with the ultrasound beam fails in a case where a difference value of the feature values in at least one frame continuous in time series in the ultrasound images of the plurality of frames is equal to or greater than the threshold value.

Alternatively, the ultrasound images of the plurality of frames may be ultrasound images that are acquired by the image acquisition unit while changing the tilt angle of the ultrasound probe at a constant speed while the contact position of the ultrasound probe with the subject is fixed, and in this case, the scanning success/failure determination unit may determine that the scanning with the ultrasound beam is successful in a case where a difference value of the feature values between any frames continuous in time series in the ultrasound images of the plurality of frames is smaller than a given threshold value, and symmetry of a distribution of the feature values with respect to a time axis is acknowledged, and may determine that the scanning with the ultrasound beam fails in a case where a difference value of the feature values in at least one frame continuous in time series in the ultrasound images of the plurality of frames is equal to or greater than the threshold value or in a case where the symmetry of the distribution of the feature values with respect to the time axis is not acknowledged.

For example, the scanning success/failure determination unit may determine that the symmetry of the distribution of the feature values with respect to the time axis is acknowledged in a case where a position where the feature value is maximized is positioned in a middle point of a pair of positions where the feature value is minimized, on the time axis, and may determine that the symmetry of the distribution of the feature values with respect to the time axis is not acknowledged in a case where the position where the feature value is maximized deviates from the middle points of the pair of positions where the feature value is minimized, on the time axis.

The ultrasound diagnostic apparatus may further comprise a tilt angle sensor that measures the tilt angle of the ultrasound probe, and the scanning success/failure determination unit may determine that the scanning with the ultrasound beam is successful in a case where a difference value of the feature values between any frames continuous in time series in the ultrasound images of the plurality of frames is smaller than a given threshold value, and a position where the feature value indicates an extreme value is acknowledged to coincide with a position where the tilt angle measured by the tilt angle sensor indicates an extreme value, on a time axis, and may determine that the scanning with the ultrasound beam fails in a case where a difference value of the feature values in at least one frame continuous in time series is equal to or greater than the threshold value or the position where the feature value with respect to the time axis indicates the extreme value is not acknowledged to coincide with the position where the tilt angle measured by the tilt angle sensor indicates the extreme value.

In this case, the ultrasound diagnostic apparatus may further comprise a target distance estimation unit that estimates a distance between a center of the bladder of the subject and the contact position of the ultrasound probe with the subject in a direction along a body surface of the subject based on an ultrasound image of a frame representing a tomographic plane passing the center of the bladder of the subject among the ultrasound images of the plurality of frames acquired by the image acquisition unit and the tilt angle of the ultrasound probe measured by the tilt angle sensor, and a probe movement guidance unit that guides a user to position the ultrasound probe directly above the center of the bladder of the subject by moving the ultrasound probe along the body surface of the subject by the distance estimated by the target distance estimation unit.

The feature value may be a position of the bladder region extracted by the bladder extraction unit in the ultrasound image.

For example, the feature value may be a position of a center of gravity of the bladder region extracted by the bladder extraction unit in the ultrasound image, and in this case, the scanning success/failure determination unit may determine that the scanning with the ultrasound beam is successful in a case where a distance between the centers of gravity of the bladder regions in frames continuous in time series is smaller than a given threshold value, and may determine that the scanning with the ultrasound beam fails in a case where the distance between the centers of gravity of the bladder regions in the frames continuous in time series is equal to or greater than the given threshold value.

The scanning success/failure determination unit may determine that the scanning with the ultrasound beam is successful in a case where a ratio of an area of a region where the bladder regions overlap each other to an area of a region occupied by at least one of the bladder regions in the frames continuous in time series is equal to or greater than a given threshold value, and may determine that the scanning of the ultrasound beam fails in a case where the ratio of the area of the region where the bladder regions overlap each other to the area of the region occupied by at least one of the bladder regions in the frames continuous in time series is smaller than the given threshold value.

The ultrasound diagnostic apparatus may further comprise a notification unit that, in a case where the scanning success/failure determination unit determines that the scanning of the ultrasound beam fails, notifies a user that the scanning of the ultrasound beam fails.

It is preferable that the image acquisition unit acquires a first group of ultrasound images of a plurality of frames corresponding to the plurality of tomographic planes of the bladder of the subject along a lateral direction and a second group of ultrasound images of a plurality of frames corresponding to the plurality of tomographic planes of the bladder of the subject along a longitudinal direction, the bladder extraction unit extracts the bladder region from each of the first group of the ultrasound images of the plurality of frames and the second group of the ultrasound images of the plurality of frames, the feature value calculation unit calculates the feature value from each of the first group of the ultrasound images of the plurality of frames and the second group of the ultrasound images of the plurality of frames, and the scanning success/failure determination unit determines whether or not the scanning of the bladder of the subject with the ultrasound beam is successful for each of the first group of the ultrasound images of the plurality of frames and the second group of the ultrasound images of the plurality of frames.

In this case, it is preferable that the ultrasound diagnostic apparatus further comprises a bladder volume calculation unit that calculates a volume of the bladder based on a maximum diameter of the bladder region measured from the first group of the ultrasound images of the plurality of frames in the lateral direction, a maximum diameter of the bladder region measured from the second group of the ultrasound images of the plurality of frames in the longitudinal direction, and a maximum diameter of the bladder region measured from the first group of the ultrasound images of the plurality of frames or the second group of the ultrasound images of the plurality of frames in a depth direction.

A method of controlling an ultrasound diagnostic apparatus according to another aspect of the invention comprises acquiring ultrasound images of a plurality of frames corresponding to a plurality of different tomographic planes in a subject using an ultrasound probe that is brought into contact with the subject and scans the subject with an ultrasound beam, keeping the acquired ultrasound images of the plurality of frames, extracting a bladder region from each of the ultrasound images of the plurality of frames, calculating a feature value regarding the bladder region extracted in each of the ultrasound images of the plurality of frames, and analyzing change in the calculated feature value between frames continuous in time series and determining whether or not scanning of a bladder of the subject with the ultrasound beam is successful based on an analysis result.

The ultrasound diagnostic apparatus according to the aspect of the invention comprises the bladder extraction unit that extracts the bladder region from each of the ultrasound images of the plurality of frames, the feature value calculation unit that calculates the feature value regarding the bladder region extracted by the bladder extraction unit in each of the ultrasound images of the plurality of frames, and the scanning success/failure determination unit that analyzes change in feature value calculated by the feature value calculation unit between the frames continuous in time series and determines whether or not the scanning of the bladder of the subject with the ultrasound beam is successful based on the analysis result. Therefore, it is possible to measure the urine volume in the bladder of the subject with excellent accuracy.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of the invention will be described referring to the accompanying drawings.

The description of constituent elements described below is provided based on a representative embodiment of the invention, but the invention is not limited to such an embodiment.

FIG. 1shows an ultrasound diagnostic apparatus1according to Embodiment 1 of the invention. The ultrasound diagnostic apparatus1comprises an ultrasound probe2that incorporates a transducer array2A, and a transmission unit3and a reception unit4are connected to the transducer array2A. An image generation unit5, a display controller6, and a display unit7are sequentially connected to the reception unit4. Here, the transmission unit3, the reception unit4, and the image generation unit5configure an image acquisition unit8. An image memory9is connected to the image generation unit5, and a bladder extraction unit10, a feature value calculation unit11, and a scanning success/failure determination unit12are sequentially connected to the image memory9. A maximum diameter measurement unit13and a notification unit14are connected to the scanning success/failure determination unit12. The image memory9and a bladder volume calculation unit15are connected to the maximum diameter measurement unit13, and a display controller6is connected to the bladder volume calculation unit15. The display controller6is connected to the notification unit14.

An apparatus controller16is connected to the display controller6, the image acquisition unit8, the bladder extraction unit10, the feature value calculation unit11, the scanning success/failure determination unit12, the maximum diameter measurement unit13, the notification unit14, and the bladder volume calculation unit15, and an input device17and a storage unit18are connected to the apparatus controller16. Here, the apparatus controller16and the storage unit18are connected to be transferrable information in two directions.

The display controller6, the image acquisition unit8, the bladder extraction unit10, the feature value calculation unit11, the scanning success/failure determination unit12, the maximum diameter measurement unit13, the notification unit14, the bladder volume calculation unit15, and the apparatus controller16configure a processor19.

The transducer array2A of the ultrasound probe2shown inFIG. 1has a plurality of transducers arranged in a one-dimensional or two-dimensional manner. The transducers transmit ultrasonic waves in compliance with drive signals supplied from the transmission unit3, receive ultrasound echoes from a subject, and output reception signals. Each transducer is configured by forming electrodes at both ends of a piezoelectric body made of, for example, piezoelectric ceramic represented by lead zirconatetitanate (PZT), a polymer piezoelectric element represented by poly vinylidene di fluoride (PVDF), piezoelectric single crystal represented by lead magnesium niobate-lead titanate (PMN-PT), or the like.

The transmission unit3of the image acquisition unit8includes, for example, a plurality of pulse generators, and adjusts a delay amount of each drive signal based on a transmission delay pattern selected in response to a control signal from the apparatus controller16such that the ultrasonic waves transmitted from a plurality of transducers of the transducer array2A form an ultrasound beam, and supplies the drive signals to a plurality of transducers. In this way, in a case where a pulsed or continuous-wave voltage is applied to the electrodes of each of a plurality of transducers of the transducer array2A, the piezoelectric body expands and contracts to generate a pulsed or continuous-wave ultrasonic wave from each of the transducers. An ultrasound beam is formed from a combined wave of the ultrasonic waves.

The transmitted ultrasound beam is reflected by, for example, a target, such as a part of the subject, and propagates toward the transducer array2A of the ultrasound probe2. The ultrasound echo propagating toward the transducer array2A is received by each transducer configuring the transducer array2A. In this case, each transducer configuring the transducer array2A expands and contracts with reception of the propagating ultrasound echo to generate an electrical signal, and outputs the electrical signal to the reception unit4.

The reception unit4of the image acquisition unit8executes processing of the signals output from the transducer array2A in compliance with a control signal from the apparatus controller16. As shown inFIG. 2, the reception unit4has a configuration in which an amplification unit20and an analog-digital (AD) conversion unit21are connected in series. The amplification unit20amplifies the signal input from each transducer configuring the transducer array2A and transmits the amplified signal to the AD conversion unit21. The AD conversion unit21converts the signal transmitted from the amplification unit20into a digitized reception signal and sends the converted data to the image generation unit5of the image acquisition unit8.

As shown inFIG. 3, the image generation unit5of the image acquisition unit8has a configuration in which a signal processing unit22, a digital scan converter (DSC)23, and an image processing unit24are sequentially connected in series. The signal processing unit22executes reception focus processing of giving each delay to each piece of data of the reception signal based on a reception delay pattern in response to a control signal from the apparatus controller16and performs addition (phasing addition). With the reception focus processing, a sound ray signal in which the focus of the ultrasound echo is narrowed to one scanning line is generated. The signal processing unit22performs correction of attenuation due to a propagation distance on the generated sound ray signal corresponding to a depth of a position where the ultrasonic wave is reflected, and then, executes envelope detection processing to generate a B mode image signal representing a tissue in the subject. The B mode image signal generated in this way is output to the DSC23.

The DSC23of the image generation unit5raster-converts the B mode image signal into an image signal compliant with a normal television signal scanning system to generate an ultrasound image. The image processing unit24of the image generation unit5executes various kinds of image processing, such as brightness correction, gradation correction, sharpness correction, and color correction, on the ultrasound image obtained in the DSC23, and then, outputs the ultrasound image to the display controller6and the image memory9.

The image memory9sequentially keeps the ultrasound images obtained by the image acquisition unit8. As the image memory9, a recording medium, such as a flash memory, a hard disc drive (HDD), a solid state drive (SSD), a flexible disc (FD), a magneto-optical disc (MO disc), a magnetic tape (MT), a random access memory (RAM), a compact disc (CD), a digital versatile disc (DVD), a secure digital card (SD card), or a universal serial bus memory (USB memory), a server, or the like can be used.

The bladder extraction unit10extracts a bladder region from each of ultrasound images of a plurality of frames generated by the image generation unit5of the image acquisition unit8. The bladder extraction unit10can use, for example, a method using deep learning described in Krizhevsk et al.: ImageNet Classification with Deep Convolutional Neural Networks, Advances in Neural Information Processing Systems 25, pp. 1106-1114 (2012). The bladder extraction unit10can use known methods, such as graph-cut (Y. Boykov and V. Kolmogorov, “An experimental comparison of min-cut/max-flow algorithm for energy minimization in vision”, IEEE Transactions on Pattern Analysis and Machine Intelligence, 26, 9, pp. 1123-1137, 2004.), Snakes (A. W. Michael Kass and D. Terzopoulos: “Snakes: Active contour models”, Int. J. Computer Vision, 1, 4, pp. 321-331, 1988.), and LevelSets (M. Sussman, P. Smereka and S. Osher: “A level set approach for computing solutions to incompressible two-phase flow”, J. Comput. Phys, 114, 1, pp. 146-159, 1994), as other methods to extract the bladder region.

The feature value calculation unit11calculates a feature value regarding the extracted bladder region in each of the ultrasound images of the plurality of frames from which the bladder region is extracted by the bladder extraction unit10. The feature value calculation unit11can calculate, for example, an area, a diameter, a position, or the like of the extracted bladder region as a feature value.

The scanning success/failure determination unit12analyzes change in feature value calculated by the feature value calculation unit11between frames continuous in time series and determines whether or not scanning of a bladder of the subject with an ultrasound beam is successful based on an analysis result. For example, the scanning success/failure determination unit12can determine whether or not the scanning of the bladder of the subject with the ultrasound beam is successful by analyzing continuity of change in feature value between frames continuous in time series. More specifically, for example, the scanning success/failure determination unit12determines that the scanning of the bladder of the subject with the ultrasound beam is successful in a case where a difference value of the feature values between any frames continuous in time series is smaller than a given threshold value, and determines that the scanning with the ultrasound beam fails in a case where a difference value of the feature values in at least one frame continuous in time series is equal to or greater than the threshold value.

Here, for example, as shown inFIG. 4, as the ultrasound probe2is positioned directly above a bladder B of a subject S and the ultrasound probe2is rotated over a given angle range A around a rotation axis R parallel to an arrangement direction of the transducer array2A while a contact position of the ultrasound probe2with the subject S is fixed, that is, the ultrasound probe2is rotated using a so-called swing method, ultrasound images of a plurality of frames can be acquired by the image acquisition unit8while changing a tilt angle W of the ultrasound probe2.

Here, the arrangement direction of the transducer array2A and an extension direction of the rotation axis R are perpendicular to the paper surface inFIG. 4. As the ultrasound probe2rotates around the rotation axis R, as shown inFIG. 5, a scanning plane PS1extending from the ultrasound probe2into the subject S also rotates around the rotation axis R.

The tilt angle W of the ultrasound probe2represents an angle at which the ultrasound probe2is tilted from a state in which a normal direction of the transducer array2A is directed in a direction perpendicular to a body surface of the subject S at the center of the transducer array2A of the ultrasound probe2. That is, it is assumed that the tilt angle W indicates 0 degrees in the ultrasound probe2in a state in which the direction normal to the transducer array2A is directed in the direction perpendicular to the body surface of the subject S, and has a greater value as the ultrasound probe2is further tilted from the state. In an example shown inFIGS. 4 and 5, the tilt angle W is represented as a rotation angle between the scanning plane PS1directed in the direction perpendicular to the body surface of the subject S and a scanning plane PS2in a state in which the ultrasound probe2is tilted.

The given angle range A is an angle range such that the scanning plane extending from the transducer array2A of the ultrasound probe2into the subject S passes through at least a center C of the bladder B of the subject S, and more preferably, a range of the tilt angle W of the ultrasound probe2such that the scanning plane extending from the transducer array2A of the ultrasound probe2into the subject S passes through the whole of the bladder B of the subject S.

In a case where the tilt angle W of the ultrasound probe2changes at a substantially constant speed, and a bladder region is clearly visualized in all the ultrasound images of the plurality of frames, for example, as shown inFIG. 6, the feature values calculated by the feature value calculation unit11in the ultrasound images of the plurality of frames continuously changes in compliance with change in time. In an example shown inFIG. 6, the area of the bladder region in the ultrasound image is calculated as the feature value. In this way, in a case where change in feature value is continuous with respect to a time axis, the difference value of the feature values between any frames continuous in time series is smaller than the given threshold value. Thus, the scanning success/failure determination unit12determines that the scanning of the bladder B of the subject S with the ultrasound beam is successful.

In a case where the tilt angle W of the ultrasound probe2changes extremely, in a case where the bladder region visualized in the ultrasound image is unclear, or the like, for example, as shown inFIGS. 7 and 8, the feature values calculated by the feature value calculation unit11in the ultrasound images of the plurality of frames have a portion where a change amount is discontinuous in time series. In an example shown inFIG. 7, the area of the bladder region in the ultrasound image is calculated as the feature value, and includes a change point CP1where the feature value changes extremely between frames continuous in time series. A change amount of the area of the bladder region at the change point CP1is discontinuous. A difference between the area at the change point CP1and the area of each bladder region in ultrasound images of frames preceding and following a frame corresponding to the change point CP1is equal to or greater than the given threshold value. Thus, the scanning success/failure determination unit12determines that the scanning of the bladder B of the subject S with the ultrasound beam fails.

In an example shown inFIG. 8, the area of the bladder region in the ultrasound image is calculated as the feature value, and the calculated area of the bladder region includes change points CP2and CP3where the feature value changes extremely between frames continuous in time series. In this case, both a difference between the area at the change point CP2and the area of two bladder regions in an ultrasound image of a frame following a frame corresponding to the change point CP2and a difference between the area at the change point CP3and the area of two bladder regions in an ultrasound image of a frame preceding a frame corresponding to the change point CP3are equal to or greater than the given threshold value. Thus, the scanning success/failure determination unit12determines that the scanning of the bladder B of the subject S with the ultrasound beam fails.

In a case where the scanning success/failure determination unit12determines that the scanning of the bladder B of the subject S with the ultrasound beam is successful, the maximum diameter measurement unit13measures a diameter of the bladder B of the subject S that is used by the bladder volume calculation unit15to calculate the volume of the bladder B of the subject S. In general, since the bladder B has a substantially ellipsoid shape, the volume of the bladder B is calculated as the volume of the ellipsoid. As shown inFIG. 9, an ellipsoid E has a shape symmetric with respect to an XY plane, a YZ plane, and an XZ plane, and in a case where the maximum diameter of the ellipsoid E in the X direction is LX, the maximum diameter of the ellipsoid E in the Y direction is LY, the maximum diameter of the ellipsoid E in the Z direction is LZ, and a circular constant is π, the volume of the ellipsoid E can be calculated by (LX×LY×LZ)/(6π).

Accordingly, in a case of calculating the volume of the bladder B of the subject S, for example, as shown inFIG. 10, each of three directions of a lateral direction D1in a case of facing the subject S from the front, a longitudinal direction D2along a height direction of the subject S, and a depth direction (not shown) perpendicular to both the lateral direction D1and the longitudinal direction D2is regarded any of the X direction, the Y direction, or the Z direction in the ellipsoid E, and the ultrasound probe2is disposed at each of a first contact position PP1for observing a tomographic plane of the bladder B along the lateral direction D1of the subject S and a second contact position PP2for observing a tomographic plane of the bladder B along the longitudinal direction D2of the subject S to generate ultrasound images of a plurality of frames. Each of the first contact position PP1and the second contact position PP2inFIG. 10indicates that the ultrasound probe2is brought into contact with the body surface of the subject S such that the arrangement direction of the transducer array2A of the ultrasound probe2extends along the lateral direction D1and the longitudinal direction D2.

The maximum diameter measurement unit13measures the maximum diameter of a bladder region in a first group of ultrasound images of a plurality of frames corresponding to a plurality of tomographic planes along the lateral direction D1of the subject S and the maximum diameter of a bladder region in a second group of ultrasound images of a plurality of frames corresponding to a plurality of tomographic planes along the longitudinal direction D2of the subject S. Here, for example, the maximum diameter measurement unit13selects a representative frame where the area of the bladder region is maximized, among the first group of the ultrasound images of the plurality of frames corresponding to the plurality of tomographic plane along the lateral direction D1of the subject S, and as shown inFIG. 11, measures the maximum diameter of a bladder region BR1in an ultrasound image U1of the selected representative frame, that is, the maximum diameter of the bladder B in the lateral direction D1of the subject S. In this case, for example, the maximum diameter measurement unit13can measure the maximum diameter of the bladder region in the ultrasound image U1by disposing a measurement line ML1having the maximum length with two points on the contour of the bladder region BR1as endpoints on the ultrasound image U1and measuring the length of the disposed measurement line ML1. In an example shown inFIG. 11, the measurement line ML1corresponding to the maximum diameter of the bladder region BR1in a horizontal direction of the ultrasound image U1is disposed on the ultrasound image U1.

For example, the maximum diameter measurement unit13selects a representative frame where the area of the bladder region is maximized, among the second group of the ultrasound images of the plurality of frames corresponding to the plurality of tomographic planes along the longitudinal direction D2of the subject S, and as shown inFIG. 12, measures the maximum diameter of a bladder region BR2in the longitudinal direction of the subject S and the maximum diameter of the bladder region BR2in the depth direction of the subject S from an ultrasound image U2of the selected representative frame. In this case, for example, the maximum diameter measurement unit13can dispose a measurement line ML2having the maximum length with two points on the contour of the bladder region BR1as endpoints and a measurement line ML3having the maximum length in a direction perpendicular to the measurement line ML2with two points on the contour of the bladder region BR1as endpoints on the ultrasound image U2, can measure the length of the disposed measurement line ML2as the maximum diameter of the subject S in the longitudinal direction D2, and can measure the length of the measurement line ML3as the maximum diameter of the subject S in the depth direction.

Here, as shown inFIG. 12, in the ultrasound image U2representing the tomographic plane along the longitudinal direction D2of the subject S, the bladder region BR2is visualized in a tilted state due to a posture of the subject S and the tilt angle W of the ultrasound probe2; however, the maximum diameter measurement unit13can obtain the maximum diameters of the bladder B in the depth direction and the longitudinal direction D2of the subject S with excellent accuracy by setting the two measurement lines ML2and ML3perpendicular to each other for the bladder region BR2and measuring the lengths of the set measurement lines ML2and ML3.

The bladder volume calculation unit15calculates the volume of the bladder B of the subject S by applying each of the maximum diameters in the three directions of the bladder region BR1or BR2measured by the maximum diameter measurement unit13, that is, the maximum diameter of the bladder B in the lateral direction D1of the subject S, the maximum diameter of the bladder B in the longitudinal direction D2of the subject S, and the maximum diameter of the bladder B in the depth direction of the subject S to any of the maximum diameter LX in the X direction, the maximum diameter LY in the Y direction, or the maximum diameter LZ in the Z direction of the ellipsoid E shown inFIG. 9and calculating (LX×LY×LZ)/(6π). The bladder volume calculation unit15displays the calculated volume of the bladder B of the subject S as a urine volume in the bladder B on the display unit7.

The notification unit14notifies a user of a determination result of the scanning success/failure determination unit12, and the like. For example, in a case where determination is made that the scanning of the bladder B of the subject S with the ultrasound beam fails, the notification unit14notifies the user that the scanning with the ultrasound beam fails. In this case, the notification unit14may notify the user that the bladder B of the subject S is imaged again, along with the effect that the scanning of the bladder B of the subject S with the ultrasound beam fails. For example, in a case where the scanning of the bladder B of the subject S with the ultrasound beam is successful, the notification unit14may notify the user that the scanning with the ultrasound beam is successful. In a case where only one of the tomographic plane along the lateral direction or the tomographic plane along the longitudinal direction of the bladder B of the subject S is imaged, the notification unit14may notify the user that another tomographic plane of the bladder B is imaged.

The notification unit14can display information representing the notification to the user on the display unit7through the display controller6. For example, in a case where the ultrasound diagnostic apparatus1comprises a speaker (not shown), the notification unit14can give notification to the user by generating voice through a speaker.

The apparatus controller16controls each unit of the ultrasound diagnostic apparatus1based on a program stored in advance in the storage unit18or the like and an input operation of the user through the input device17.

The display controller6displays the ultrasound image generated by the image generation unit5of the image acquisition unit8, and the like on the display unit7under the control of the apparatus controller16.

The display unit7displays the ultrasound image generated by the image acquisition unit8, and the like, and includes, for example, a display device, such as a liquid crystal display (LCD) or an organic electroluminescence display (organic EL display).

The input device17is provided for the user to perform an input operation, and can comprise a keyboard, a mouse, a trackball, a touch pad, a touch panel, and the like.

The storage unit18stores an operation program and the like of the ultrasound diagnostic apparatus1, and a recording medium, such as a flash memory, an HDD, an SSD, an FD, an MO disc, an MT, a RAM, a CD, a DVD, an SD card, or a USB memory, a server, or the like can be used.

The processor19having the display controller6, the image acquisition unit8, the bladder extraction unit10, the feature value calculation unit11, the scanning success/failure determination unit12, the maximum diameter measurement unit13, the notification unit14, the bladder volume calculation unit15, and the apparatus controller16is configured of a central processing unit (CPU) and a control program causing the CPU to execute various kinds of processing. However, the processor19may be configured using a field programmable gate array (FPGA), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a graphics processing unit (GPU), or other integrated circuits (ICs) or may be configured by combining the ICs.

The display controller6, the image acquisition unit8, the bladder extraction unit10, the feature value calculation unit11, the scanning success/failure determination unit12, the maximum diameter measurement unit13, the notification unit14, the bladder volume calculation unit15, and the apparatus controller16of the processor19can be configured to be partially or wholly integrated into one CPU or the like.

Next, the operation of the ultrasound diagnostic apparatus1in Embodiment 1 will be described in detail referring to a flowchart ofFIG. 13.

First, in Step S1, as shown inFIG. 10, the ultrasound probe2is disposed at the first contact position PP1of the subject S, and the ultrasound probe2is brought into contact with the body surface of the subject S by the user such that the ultrasound image U1representing the tomographic plane of the bladder B along the lateral direction D1of the subject S is acquired. The ultrasound beam is emitted from the ultrasound probe2into the subject S, and the first group of the ultrasound images U1representing the tomographic plane of the bladder B along the lateral direction D1of the subject S is acquired by the image acquisition unit8. Subsequently, the first group of the ultrasound images U1is continuously sequentially acquired by the image acquisition unit8.

In Step S2, determination is made whether or not storage of the ultrasound image U1acquired at present by the image acquisition unit8in the image memory9is started. For example, as a command to store the ultrasound image U1acquired at present in the image memory9is issued by the user through the input device17, the storage of the ultrasound image U1is started. In a case where determination is made in Step S2that the storage of the ultrasound image U1is not started because the command to store the ultrasound image U1is not issued by the user, or the like, the determination of Step S2is performed again. In Step S2, in a case where determination is made that the storage of the ultrasound image U1is started, the process progresses to Step S3.

In Step S3, the image generation unit5of the image acquisition unit8sends the first group of the generated ultrasound images U1to the image memory9under the control of the apparatus controller16. The image memory9stores the first group of the ultrasound images U1sent from the image generation unit5.

In subsequent Step S4, determination is made whether or not the storage of the ultrasound image U1in the image memory9ends. For example, as a command to end the storage of the ultrasound image U1at present is issued by the user through the input device17, the storage of the ultrasound image U1ends. In a case where determination is made in Step S4that the storage of the ultrasound image U1does not end and is continued because the command to end the storage of the ultrasound image U1is not issued by the user, or the like, the process returns to Step S3, and the first group of the ultrasound image U1newly acquired by the image acquisition unit8is stored in the image memory9. In this manner, in Step S4, until determination is made that the storage of the ultrasound image U1ends, the first group of the ultrasound image U1is continuously stored in the image memory9.

Here, while the first group of the ultrasound image U1is continuously stored in the image memory9, as shown inFIG. 4, the user changes the tilt angle W of the ultrasound probe2over the given angle range A with respect to the subject S while the contact position of the ultrasound probe2with the subject S is fixed at the first contact position PPE With this, the first group of the ultrasound images U1of the plurality of frames corresponding to the different tilt angles W of the ultrasound probe2is stored in the image memory9.

In Step S4, in a case where determination is made that the storage of the ultrasound image U1ends, the process progresses to Step S5.

In Step S5, the bladder extraction unit10extracts the bladder region BR1from each of the first group of the ultrasound images U1of the plurality of frames stored in the image memory9with the repetition of Steps S3and S4. The bladder extraction unit10can extract bladder region BR1in the ultrasound image U1using, for example, a so-called pattern matching method.

In subsequent Step S6, the feature value calculation unit11calculates the feature value regarding the extracted bladder region BR1on the first group of the ultrasound images U1of the plurality of frames from which the bladder region BR1is extracted in Step S5. For example, the feature value calculation unit11can calculate the area of the extracted bladder region BR1as the feature value.

In Step S7, the scanning success/failure determination unit12analyzes change in feature value calculated in Step S6between frames continuous in time series and determines whether or not the scanning of the bladder of the subject with the ultrasound beam is successful based on an analysis result. For example, in a case where the area of the bladder region BR1is calculated as the feature value in Step S6, the scanning success/failure determination unit12determines that the scanning of the bladder B of the subject S with the ultrasound beam is successful in a case where a difference value of the areas of the bladder regions BR1between any frames continuous in time series is smaller than a given threshold value, and determines that the scanning with the ultrasound beam fails in a case where a difference value of the feature values in at least one frame continuous in time series is equal to or greater than the threshold value.

That is, as shown inFIG. 6, in a case where the area of the bladder region BR1calculated in Step S6has continuity with respect to the time axis, the scanning success/failure determination unit12determines that the scanning of the bladder B of the subject S with the ultrasound beam is successful, and as shown inFIGS. 7 and 8, in a case where there are the change point CP1, CP2, or CP3where the area of the bladder region BR1calculated in Step S6changes extremely between frames continuous in time series, the scanning success/failure determination unit12determines that the scanning with the ultrasound beam fails.

In Step S7, in a case where determination is made that the scanning of the bladder B of the subject S with the ultrasound beam fails, the process progresses to Step S8. In Step S8, the notification unit14notifies the user that the scanning of the bladder B of the subject S with the ultrasound beam fails. For example, as shown inFIG. 14, the notification unit14can display a guide panel G1including information representing the effect that scanning fails and the effect that the tomographic plane of the bladder B of the subject S is imaged again, on the display unit7. In an example shown inFIG. 14, the guide panel G1includes text data “Scanning fails. Please image lateral tomographic plane of bladder again.” and is displayed on the display unit7to be superimposed on the ultrasound image U1.

In this manner, in a case where the processing of Step S8is completed, the process returns to Step S2, and determination is made whether or not the storage of the ultrasound image U1is newly started. In a case where determination is made in Step S2that the storage of the ultrasound image U1is started, the process progresses to Step S3, the first group of ultrasound images U1is newly stored in the image memory9. In subsequent Step S4, Steps S3and S4are repeated until determination is made that the storage of the ultrasound image U1ends, and the first group of the ultrasound images U1of the plurality of frames is newly stored in the image memory9.

In a case where determination is made in Step S4that the storage of the ultrasound image U1ends, the process progresses to Step S5, and the bladder region BR1is extracted in the first group of the ultrasound images U1of the plurality of frames newly stored in the image memory9by the repetition of Steps S3and S4. In subsequent Step S6, the feature value regarding the bladder region BR1extracted in the first group of the ultrasound images U1of the plurality of frames is calculated, in Step S7, change in feature value between continuous frames of the first group of the ultrasound images U1of the plurality of frames is analyzed, and determination is made whether or not the scanning of the bladder B of the subject S with the ultrasound beam is successful based on an analysis result. In Step S7, in a case where determination is made that the scanning of the bladder B of the subject S with the ultrasound beam fails, the process progresses to Step S8, the user is notified that the scanning with the ultrasound beam fails, and the process returns to Step S2.

In this way, in Step S7, until determination is made that the scanning of the bladder B of the subject S with the ultrasound beam is successful, the processing of Steps S2to S8is repeated, and determination is made whether or not new scanning of the bladder B of the subject S with the ultrasound beam is successful. With this, the first group of the ultrasound images U1of the plurality of frames with the bladder region BR1clearly shown in all the whole ultrasound images U1is obtained.

In Step S7, in a case where determination is made that the scanning of the bladder B of the subject S with the ultrasound beam is successful, the process progresses to Step S9. In Step S9, determination is made whether or not both the scanning with the ultrasound beam in the tomographic plane along the lateral direction of bladder B of the subject S and the scanning with the ultrasound beam in the tomographic plane along the longitudinal direction of the bladder B are completed. At the moment, only the scanning with the ultrasound beam in the tomographic plane along the lateral direction of the bladder B of the subject S is completed, the scanning with the ultrasound beam in the tomographic plane along the longitudinal direction of the bladder B of the subject S is not completed. Thus, in Step S9, determination is made that the scanning of the ultrasound beam in two tomographic planes of the tomographic plane along the lateral direction and the tomographic plane along the longitudinal direction of the bladder B of the subject S is not completed, and the process progresses to Step S10.

In Step S10, the notification unit14gives a command to the user to the effect that the scanning of the ultrasound beam is not completed and the scanning with the ultrasound beam in the remaining tomographic plane is performed. For example, as shown inFIG. 15, the notification unit14can display a guide panel G2including information representing the effect that scanning is successful and the effect that the remaining tomographic plane is imaged, on the display unit7. In an example shown inFIG. 15, the guide panel G2includes text data “Scanning is successful. Please image longitudinal tomographic plane of bladder.” and is displayed on the display unit7to be superimposed on the ultrasound image U1.

In compliance with the command by the notification unit14in Step S10, as shown inFIG. 10, the user disposes the ultrasound probe2at the second contact position PP2of the subject S and brings the ultrasound probe2into contact with the body surface of the subject S such that a second group of an ultrasound image U2representing a tomographic plane along the longitudinal direction of the bladder B of the subject, that is, a tomographic plane of the bladder B along the longitudinal direction D2of the subject S is acquired. In this state, the ultrasound beam is emitted from the ultrasound probe2into the subject S, and the second group of the ultrasound image U2representing the tomographic plane of the bladder B along the longitudinal direction D2of the subject S is acquired by the image acquisition unit8.

In this manner, the process returns from Step S10to Step S2, and the processing of Steps S2to S8is executed using the ultrasound probe2disposed at the second contact position PP2of the subject S. In regards to Steps S2to S8, similarly to a case where the scanning with the ultrasound beam is performed in the tomographic plane of the bladder B along the lateral direction D1of the subject S, the second group of the ultrasound images U2of the plurality of frames is newly stored in the image memory9, and the bladder region BR2is extracted in the second group of the ultrasound images U2of the plurality of frames newly stored in the image memory9.

The feature value regarding the extracted bladder region BR2is calculated, determination is made whether or not the scanning of the bladder B of the subject S with the ultrasound beam is successful based on change in calculated feature value between continuous frames, and the processing of Steps S2to S8is repeated until determination is made that the scanning with the ultrasound beam is successful. With this, the second group of the ultrasound images U2of the plurality of frames with the bladder region BR2clearly shown in all the ultrasound images U2is obtained.

In Step S7, in a case where determination is made that the scanning with the ultrasound beam in the tomographic plane of the bladder B along the longitudinal direction D2of the subject S is successful, the process progresses to Step S9.

In Step S9, determination is made whether or not both the scanning with the ultrasound beam in the tomographic plane of the bladder B along the lateral direction D1of the subject S and the scanning with the ultrasound beam in the tomographic plane of the bladder B along the longitudinal direction of the subject S are completed. At the moment, both the scanning with the ultrasound beam in the tomographic plane of the bladder B along the lateral direction D1of the subject S and the scanning with the ultrasound beam in the tomographic plane of the bladder B along the longitudinal direction D2of the subject S are completed, and thus, the process progresses to Step S11.

In Step S11, the maximum diameter measurement unit13measures the maximum diameter of the bladder region BR1in the first group of the ultrasound images U1of the plurality of frames corresponding to the plurality of tomographic planes of the bladder B along the lateral direction D1of the subject S and the maximum diameter of the bladder region BR2in the second group of the ultrasound images U2of the plurality of frames corresponding to the plurality of tomographic planes of the bladder B along the longitudinal direction D2of the subject S.

For example, in a case where the area of the bladder region BR1is calculated as the feature value in Step S6, the maximum diameter measurement unit13selects a representative frame where the area of the bladder region BR1is maximized, among the first group of the ultrasound images U1of the plurality of frames corresponding to the plurality of tomographic planes along the lateral direction of the subject S, for example, with reference to the area of the bladder region BR1calculated in Step S6, and as shown inFIG. 11, measures the maximum diameter of the bladder region BR1in the lateral direction of the ultrasound image U1of the selected representative frame as the maximum diameter of the bladder B of the subject S in the lateral direction D1of the subject S. In this case, the maximum diameter measurement unit13can measure the maximum diameter of the bladder region BR1in the ultrasound image U1, for example, by disposing the measurement line ML1having the maximum length in the lateral direction D1with the two points on the contour of the bladder region BR1as endpoints on the ultrasound image U1and measuring the length of the disposed measurement line ML1.

The maximum diameter measurement unit13selects a representative frame where the area of the bladder region BR2is maximized, among the second group of the ultrasound images U2of the plurality of frames corresponding to the plurality of tomographic planes along the longitudinal direction of the subject S, for example, with reference to the area of the bladder region BR2calculated in Step S6, and as shown inFIG. 12, measures the maximum diameter of the bladder B in the longitudinal direction D2of the subject S and the maximum diameter of the bladder B in the depth direction of the subject S from the bladder region BR2in the ultrasound image U2of the selected representative frame. In this case, for example, the maximum diameter measurement unit13can dispose the measurement line ML2having the maximum length with the two points on the contour of the bladder region BR2as endpoints and the measurement line ML3having the maximum length in the direction perpendicular to the measurement line ML2with the two points on the contour of the bladder region BR2as endpoints on the ultrasound image U2, can measure the length of the disposed measurement line ML2as the maximum diameter of the bladder B in the longitudinal direction D2of the subject S, and can measure the length of the measurement line ML3as the maximum diameter of the bladder B in the depth direction of the subject S.

In subsequent Step S12, the bladder volume calculation unit15calculates the volume of the bladder B of the subject S by applying the maximum diameters of the bladder B in the lateral direction D1, the longitudinal direction D2, and the depth direction of the subject S measured in Step S11to the maximum diameter LX in the X direction, the maximum diameter LY in the Y direction, and the maximum diameter LZ in the Z direction of the ellipsoid E shown inFIG. 9, denoting the circular constant as7E, and calculating (LX×LY×LZ)/(6π). Though not shown, the bladder volume calculation unit15displays the calculated volume of the bladder B of the subject S as the urine volume of the bladder B of the subject S on the display unit7.

In a case where the processing of Step S12is completed, the operation of the ultrasound diagnostic apparatus1ends.

From the above description, since the scanning success/failure determination unit12determines whether or not the scanning of the bladder B of the subject S with the ultrasound beam is successful, the maximum diameter measurement unit13measures the maximum diameters in the lateral direction D1, the longitudinal direction D2, and the depth direction of the subject S from the first group of the ultrasound images U1of the plurality of frames with the bladder region BR1clearly visualized in all the ultrasound images U1and the second group of the ultrasound images U2of the plurality of frames with the bladder region BR2clearly visualized in all the ultrasound images U2with excellent accuracy, and the bladder volume calculation unit15calculates the volume of the bladder B of the subject S as the urine volume in the bladder B based on the measured maximum diameters in the lateral direction, the longitudinal direction, and in the depth direction of the bladder B of the subject S. For this reason, with the ultrasound diagnostic apparatus1according to Embodiment 1 of the invention, it is possible to measure the urine volume in the bladder B of the subject S with excellent accuracy.

In Step S2, although an example where the storage of the ultrasound image U1or U2in the image memory9is started with the command to store the ultrasound image U1or U2issued by the user through the input device17as a trigger, and in Step S4, the storage of the ultrasound image U1or U2ends with the command to end the storage of the ultrasound image U1or U2issued by the user through the input device17as a trigger has been exemplified, the trigger for starting the storage of the ultrasound image U1or U2and the trigger for ending the storage of the ultrasound image U1or U2are not limited thereto.

For example, in Step S2, the storage of the ultrasound image U1or U2can be automatically started instead of performing determination about whether or not the storage of the ultrasound image U1or U2is started.

The storage of the ultrasound image U1or U2may end in a case where a given time, for example, 15 seconds elapse after the storage of the ultrasound image U1or U2is started in Step S2.

Alternatively, for example, a probe contact determination unit that analyzes the acquired ultrasound image U1or U2to determine whether or not the ultrasound probe2is in contact with the subject S or is apart from the subject S may be provided in the ultrasound diagnostic apparatus1, the storage of the ultrasound image U1or U2may start with determination by the probe contact determination unit that the ultrasound probe2is in contact with the subject S, as a trigger, and the storage of the ultrasound image U1or U2may end with determination by the probe contact determination unit that the ultrasound probe2is apart from the subject S, as a trigger.

In a case where determination is made in Step S7that the scanning of the bladder B of the subject S with the ultrasound beam fails, the effect that the scanning with the ultrasound beam fails is notified in Step S8, the process returns to Step S2, and determination is made whether or not to newly store the ultrasound image U1or U2; however, even in a case where determination is made that the scanning with the ultrasound beam fails, the urine volume in the bladder B of the subject S may be calculated using the ultrasound image U1or U2of the plurality of frames already stored in the image memory9.

For example, in a case where the area of the bladder region BR1or BR2is calculated as the feature value by the feature value calculation unit11, as shown inFIG. 16, the maximum diameter measurement unit13can select a frame where the area is maximized, as a representative frame from the ultrasound images U1or U2of a plurality of frames excluding ultrasound images of frames corresponding to a section T1between a change point CP4and a change point CP5where the calculated area changes extremely with respect to the time axis, to measure the maximum diameter of the bladder region BR1or BR2. The bladder volume calculation unit15calculates the volume of the bladder B of the subject S as the urine volume in the bladder B of the subject S based on the maximum diameters of the bladder region BR1or BR2calculated by the maximum diameter measurement unit13in this manner.

With this, it is possible to calculate the urine volume in the bladder B of the subject S using only the ultrasound images U1or U2of the plurality of frames where the feature value changes continuously, and thus, it is possible to improve the measurement accuracy of the urine volume.

Although an example where the feature value calculation unit11calculates the area of the bladder region BR1or BR2in the ultrasound image U1or U2as the feature value has been exemplified, the feature value calculation unit11may calculate the diameter of the bladder region BR1or BR2as the feature value. For example, in a case where the ultrasound probe2is disposed at the first contact position PP1shown inFIG. 10and the tomographic plane of the bladder B along the lateral direction D1of the subject S is visualized in the ultrasound image U1, as shown inFIG. 11, the feature value calculation unit11can calculate a diameter of the bladder region BR1represented by the measurement line ML1as the diameter of the bladder region BR1. Here, the diameter of the bladder region BR1represented by the measurement line ML1is the maximum diameter of the bladder region BR1in the lateral direction of the ultrasound image U1and corresponds to the maximum diameter of the bladder B of the subject S in the lateral direction D1of the subject S.

For example, in a case where the ultrasound probe2is disposed at the second contact position PP2shown inFIG. 10, and the tomographic plane of the bladder B along the longitudinal direction D2of the subject S is visualized in the ultrasound image U2, as shown inFIG. 12, the feature value calculation unit11can calculate a diameter of the bladder region BR2represented by the measurement line ML2or a diameter of the bladder region BR2represented by the measurement line ML3as the diameter of the bladder region BR2. Here, the diameter of the bladder region BR2represented by the measurement line ML2is the maximum diameter of the bladder region BR2, and corresponds to the maximum diameter of the bladder B of the subject S in the depth direction of the subject S. The diameter of the bladder region BR2represented by the measurement line ML3is the maximum diameter of the bladder region BR2in the direction perpendicular to the measurement line ML2, and corresponds to the maximum diameter of the bladder B of the subject S in the longitudinal direction D2of the subject S.

For example, in a case where the feature value calculation unit11calculates the diameter of the bladder region BR1or BR2in the ultrasound image U1or U2as the feature value, the scanning success/failure determination unit12can determine that the scanning of the bladder B of the subject S with the ultrasound beam is successful in a case where a difference of the diameters of the bladder region BR1or BR2between frames continuous in time series is smaller than a given threshold value, and can determine that the scanning with the ultrasound beam fails in a case where the difference of the diameters of the bladder region BR1or BR2in at least one frame continuous in time series is equal to or greater than the threshold value. The maximum diameter measurement unit13can select a frame where the diameter of the bladder region BR1or BR2is maximized, as the representative frame among the ultrasound images of the plurality of frames, for example, with reference to the diameter of the bladder region BR1or BR2calculated by the feature value calculation unit11, and can set the diameters measured from the bladder region BR1or BR2in the ultrasound image of the selected frame as the maximum diameters of the bladder B of the subject S in the lateral direction D1, the longitudinal direction D2, and the depth direction of the subject S. The bladder volume calculation unit15calculates the volume of the bladder B as the urine volume in the bladder B based on the maximum diameters of the bladder B in the lateral direction D1, the longitudinal direction D2, and the depth direction of the subject S measured by the maximum diameter measurement unit13.

In this way, even in a case where the feature value calculation unit11calculates the diameter of the bladder region BR1or BR2in the ultrasound image U1or U2as the feature value, similarly to the case where the area of the bladder region BR1or BR2is calculated as the feature value, the scanning success/failure determination unit12determines whether or not the scanning of the bladder B of the subject S with the ultrasound beam is successful, and the urine volume in the bladder B of the subject S is calculated from the ultrasound images U1or U2of the plurality of frames where the scanning with the ultrasound beam is successful. Thus, it is possible to measure the urine volume in the bladder B of the subject S with excellent accuracy.

For example, the feature value calculation unit11may calculate a position of the bladder region BR1or BR2in the ultrasound image U1or U2as a feature value. For example, as shown inFIG. 17, the feature value calculation unit11can calculate a position of a center of gravity CG1of a bladder region BR3in an ultrasound image U3as a feature value. In this case, from an ultrasound image U3and an ultrasound image U4continuous in time series, the scanning success/failure determination unit12can calculate an inter-center-of-gravity distance LG between a center of gravity CG1of a bladder region BR3of the ultrasound image U3and a center of gravity CG2of a bladder region BR4of the ultrasound image U4. Here, inFIG. 17, for description, although the ultrasound image U3and the ultrasound image U4are disposed to slightly deviate from each other, actually, the inter-center-of-gravity distance LG between the center of gravity CG1of the bladder region BR3and the center of gravity CG2of the bladder region BR4is calculated in a state in which the ultrasound image U3and the ultrasound image U4are disposed to overlap each other without deviating from each other.

The scanning success/failure determination unit12can determine that the scanning of the bladder B of the subject S with the ultrasound beam is successful in a case where the inter-center-of-gravity distance LG between any frames continuous in time series is smaller than a given threshold value, and can determine that the scanning with the ultrasound beam fails in a case where the inter-center-of-gravity distance LG in at least one frame continuous in time series is equal to or greater than the given threshold value. For example, as shown inFIG. 18, in a case where there is the inter-center-of-gravity distance LG equal to or greater than a given threshold value H1among a plurality of inter-center-of-gravity distances LG calculated from the ultrasound images of the plurality of frames, the scanning success/failure determination unit12determines that the scanning of the bladder B of the subject S with the ultrasound beam fails.

The scanning success/failure determination unit12may perform both of a success/failure determination regarding the scanning with the ultrasound beam using the inter-center-of-gravity distance LG between the frames continuous in time series and a success/failure determination regarding the scanning with the ultrasound beam using the difference of the areas of the bladder region BR3or the difference of the diameters of the bladder region BR3between the frames continuous in time series, may make final determination that the scanning with the ultrasound beam is successful in a case where determination is made that the scanning with the ultrasound beam is successful through both the success/failure determinations, and may make final determination that the scanning with the ultrasound beam fails in a case where determination is made that the scanning with the ultrasound beam fails through at least one success/failure determination. With this, it is possible to acquire ultrasound images U3and U4of a plurality of frames where the scanning of the bladder B of the subject S with the ultrasound beam is successful, with excellent accuracy, and thus, it is possible to improve the measurement accuracy of the urine volume in the bladder B of the subject S.

Even in a case where the scanning success/failure determination unit12determines that the scanning of the bladder B of the subject S with the ultrasound beam fails, for example, as shown inFIG. 18, the maximum diameter measurement unit13may measure the maximum diameter of the bladder B in the lateral direction D1, the longitudinal direction D2, and the depth direction of the subject S from the ultrasound images of the plurality of frames other than frames in a section T2where the inter-center-of-gravity distance LG is greater than the given threshold value HE In this case, the bladder volume calculation unit15calculates the volume of the bladder B of the subject S using only the ultrasound images of the frames where the scanning with the ultrasound beam is successful, and thus, it is possible to improve the measurement accuracy of the urine volume in the bladder B.

For example, as shown inFIG. 19, the feature value calculation unit11may calculate the areas and the positions of the bladder regions BR3and BR4in the ultrasound images U3and U4as the feature value. In this case, the scanning success/failure determination unit12can calculate a ratio of an area of a region RB where the bladder region BR3and the bladder region BR4overlap each other to an area of a region RA occupied by at least one of the bladder region BR3in the ultrasound image U3or the bladder region BR4in the ultrasound image U4from the ultrasound image U3and the ultrasound image U4continuous in time series. Here, inFIG. 19, for description, although the ultrasound image U3and the ultrasound image U4are disposed to slightly deviate from each other, actually, the ratio of the area of the region RB to the area of the region RA is calculated in a state in which the ultrasound image U3and the ultrasound image U4overlap each other without deviating from each other.

Here, as shown inFIG. 4, while the ultrasound probe2is tilted in the given angle range A, in a case where the ultrasound probe2is tilted from a state in which the scanning plane PS1passes through the center C of the bladder B of the subject S, the scanning plane PS1is gradually apart from the center C of the bladder B. In this case, the areas of the bladder regions BR3and BR4in the ultrasound images U3and U4gradually decrease and approach 0. For this reason, in a case where the ultrasound probe2is tilted such that the tilt angle W of the ultrasound probe2changes from a lower limit value to an upper limit value of the angle range A, for example, as shown inFIG. 20, the ratio of the area of the region RB to the area of the region RA has minimum values PA and PB and change points CP6and CP7in both end portions in time series. For this reason, the scanning success/failure determination unit12determines that the scanning of the bladder B of the subject S with the ultrasound beam is successful, for example, in a case where the ratio of the area of the region RB to the area of the region RA is equal to or greater than a given threshold value H2in a section T3between the change point CP6and the change point CP7of both end portions in time series as shown inFIG. 20, and can determine that the scanning with the ultrasound beam fails in a case where the ratio of the area of the region RB to the area of the region RA is smaller than the given threshold value H2as shown inFIG. 21.

The scanning success/failure determination unit12can perform both of a success/failure determination regarding the scanning with the ultrasound beam using the ratio of the area of the region RB to the area of the region RA between the frames continuous in time series and a success/failure determination regarding the scanning with the ultrasound beam using the difference of the areas of the bladder region BR3or the difference of the diameters of the bladder region BR3between the frames continuous in time series, can make final determination that the scanning with the ultrasound beam is successful in a case where determination is made that the scanning with the ultrasound beam is successful through both the success/failure determinations, and can make final determination that the scanning with the ultrasound beam fails in a case where determination is made that the scanning with the ultrasound beam fails. With this, it is possible to acquire ultrasound images U3and U4of a plurality of frames where the scanning of the bladder B of the subject S with the ultrasound beam is successful, with excellent accuracy, and thus, it is possible to improve the measurement accuracy of the urine volume in the bladder B of the subject S.

Even in a case where the scanning success/failure determination unit12determines that the scanning of the bladder B of the subject S with the ultrasound beam fails, for example, as shown inFIG. 21, the maximum diameter measurement unit13may measure the maximum diameters of the bladder B in the lateral direction D1, the longitudinal direction D2, and the depth direction of the subject S from the ultrasound images of the plurality of frames other than frames in a section T4where the ratio of the area of the region RB to the area of the region RA is smaller than the given threshold value. In this case, the bladder volume calculation unit15calculates the volume of the bladder B of the subject S using only the ultrasound images of the frames where the scanning with the ultrasound beam is successful, and thus, it is possible to improve the measurement accuracy of the urine volume in the bladder B.

In Embodiment 1, although, first, to obtain the first group of the ultrasound images U1for visualizing the tomographic plane of the bladder B along the lateral direction D1of the subject S, as shown inFIG. 10, the ultrasound probe2is disposed at the first contact position PP1, and next, to obtain the second group of the ultrasound images U2for visualizing the tomographic plane of the bladder B along the longitudinal direction D2of the subject S, the ultrasound probe2is disposed at the second contact position PP2, first, the ultrasound probe2may be disposed at the second contact position PP2to acquire the second group of the ultrasound images U2, and next, the ultrasound probe2may be disposed at the first contact position PP1to acquire the first group of the ultrasound images U1.

For example, in starting the operation of the ultrasound diagnostic apparatus1, the notification unit14may notify that the tomographic plane of the bladder B in the lateral direction D1of the subject S is imaged or that the tomographic plane of the bladder B in the longitudinal direction D2of the subject S is imaged. Though not shown, for example, the notification unit14can display information representing that the tomographic plane of the bladder B in the lateral direction D1of the subject S is imaged or information representing that the tomographic plane of the bladder B in the longitudinal direction D2of the subject S is imaged, on the display unit7.

In Embodiment 1, as shown inFIG. 4, although the single scanning with the ultrasound beam is performed in which the tilt angle W of the ultrasound probe2is changed from the lower limit value to the upper limit value or from the upper limit value to the lower limit value of the given angle range A by rotating the ultrasound probe2around the rotation axis R while the contact position of the ultrasound probe2with the subject S is fixed, a plurality of times of scanning with the ultrasound beam may be continuously performed.

Even in this case, similarly to a case where only the single scanning with the ultrasound beam is performed, the scanning success/failure determination unit12determines that a plurality of times of the scanning of the bladder B of the subject S with the ultrasound beam are successful in a case where change in feature value calculated by the feature value calculation unit11in the ultrasound images U1or U2of the plurality of frames is continuous in time series, and determines that the plurality of times of the scanning with the ultrasound beam fail in a case where the change in feature value calculated in the ultrasound images U1or U2of the plurality of frames is discontinuous in time series.

For example, in a case where the feature value calculation unit11calculates the area of the bladder region BR1or BR2in the ultrasound images U1or U2of the plurality of frames, the scanning success/failure determination unit12can determine that the plurality of times of the scanning of the bladder B of the subject S with the ultrasound beam are successful in a case where the value of the area is continuous with respect to the time axis and the difference value of the areas of the bladder region BR1or BR2between any frames continuous in time series is smaller than the given threshold value, as shown inFIG. 22. The scanning success/failure determination unit12can determine that the plurality of times of the scanning of the bladder B of the subject S with the ultrasound beam fail in a case where change in area of the bladder region BR1or BR2in time series is discontinuous and the difference value of the areas of the bladder region BR1or BR2in at least one frame continuous in time series is equal to or greater than the threshold value, as shown inFIG. 23. In an example shown inFIG. 23, the area of the bladder region BR1or BR2of the ultrasound images U1or U2of the plurality of frames has change points CP8and CP9where the difference of the areas of the bladder region BR1or BR2between preceding and following frames is equal to or greater than a given threshold value.

In this manner, even in a case where the plurality of times of the scanning with the ultrasound beam are performed, similarly to a case where only the single scanning with the ultrasound beam is performed, the scanning success/failure determination unit12determines whether or not the scanning of the bladder B of the subject S with the ultrasound beam is successful. Therefore, the urine volume in the bladder B of the subject S is measured using only the ultrasound images U1or U2of the frames where the scanning with the ultrasound beam is successful, and thus, it is possible to improve the measurement accuracy of the urine volume in the bladder B.

Although the scanning success/failure determination unit12determines whether or not the plurality of times of the scanning with the ultrasound beam are successful depending on whether or not the ultrasound images U1or U2of the plurality of frames acquired by the image acquisition unit8while the plurality of times of the scanning of the bladder B of the subject S with the ultrasound beam are performed are continuous as a whole, the scanning success/failure determination unit12may perform determination about whether or not the scanning with the ultrasound beam is successful for each scanning with the ultrasound beam among the plurality of times of the scanning with the ultrasound beam.

In this case, for example, in a case where the feature value calculation unit11calculates the area of the bladder region BR1or BR2in the ultrasound images U1or U2of the plurality of frames, as shown inFIG. 22, the scanning success/failure determination unit12detects minimum values P1, P2, P3, and P4the area of the bladder region BR1or BR2smaller than a given threshold value H3, and estimates each of a section T5between a position on the time axis indicating the minimum value P1and a position on the time axis indicating the minimum value P2, a section T6between a position on the time axis indicating the minimum value P2and a position on the time axis indicating the minimum value P3, and a section T7between a position on the time axis indicating the minimum value P3and a position on the time axis indicating the minimum value P4as a section where the single scanning with the ultrasound beam is performed. The scanning success/failure determination unit12determines whether or not the scanning of the bladder B of the subject S with the ultrasound beam is successful on each of the sections T5, T6, and T7estimated in this manner. In an example shown inFIG. 22, the area of the bladder region BR1or BR2is continuous with respect to the time axis in all the sections T5, T6, and T7, and thus, the scanning success/failure determination unit12determines that the scanning with the ultrasound beam is successful on each of the sections T5, T6, and T7.

In this case, the maximum diameter measurement unit13can select an ultrasound image of one representative frame where the area of the bladder region BR1or BR2is maximized, among the ultrasound images U1or U2of a plurality of frames corresponding to the sections T5, T6, and T7, for example, and measure the maximum diameter of the bladder region BR1or BR2from the selected ultrasound image of the representative frame. The maximum diameter measurement unit13can select an ultrasound image of a first representative frame where the area of the bladder region BR1or BR2is maximized, in the ultrasound images of a plurality of frames corresponding to the section T5, an ultrasound image of a second representative frame where the area of the bladder region BR1or BR2is maximized in the ultrasound images of a plurality of frames corresponding to the section T6, and an ultrasound image of a third representative frame where the area of the bladder region BR1or BR2is maximized, in the ultrasound images of a plurality of frames corresponding to the section T7, and can measure the maximum diameter of the bladder region BR1or BR2from each of the ultrasound images of the selected first, second, and third representative frames. The maximum diameter measurement unit13can measure the final maximum diameter of the bladder region BR1or BR2by averaging the maximum diameters of the bladder region BR1or BR2measured from the ultrasound images of the first, second, and third representative frames.

For example, as shown inFIG. 23, in a case where the scanning success/failure determination unit12estimates four sections T5, T6, T7, and T8, the area of the bladder region BR1or BR2is continuous with respect to the time axis in the sections T6and T8, and the change of the area of the bladder region BR1or BR2in time series is discontinuous in the sections T5and T7, the scanning success/failure determination unit12determines that the scanning with the ultrasound beam is successful on the sections T6and T8, and determines that the scanning with the ultrasound beam fails on the sections T5and T7.

In this case, the maximum diameter measurement unit13can measure the maximum diameter of the bladder region BR1or BR2using the ultrasound images U1or U2of the plurality of frames corresponding to the sections T6and T8where the scanning success/failure determination unit12determines that the scanning of the bladder B of the subject S with the ultrasound beam is successful, among the ultrasound images U1or U2of the plurality of frames corresponding to the sections T5, T6, T7, and T8. For example, the maximum diameter measurement unit13can select an ultrasound image of one representative frame where the area of the bladder region BR1or BR2is maximized, among the ultrasound images U1or U2of the plurality of frames corresponding to the sections T6and T8, and can measure the maximum diameter of the bladder region BR1or BR2from the selected ultrasound image of the representative frame.

The maximum diameter measurement unit13can select an ultrasound image of a first representative frame where the area of the bladder region BR1or BR2is maximized, among the ultrasound images U1or U2of a plurality of frames corresponding to the section T6and an ultrasound image of a second representative frame where the area of the bladder region BR1or BR2is maximized, among the ultrasound images U1or U2of a plurality of frames corresponding to the section T8, and can measure the maximum diameter of the bladder region BR1or BR2from each of the ultrasound images of the first and second representative frames. The maximum diameter measurement unit13can measure the final maximum diameter of the bladder region BR1or BR2by averaging the maximum diameters of the bladder region BR1or BR2measured from the ultrasound images of the first and second representative frames.

In this manner, the scanning success/failure determination unit12estimates the sections T5to T8on the time axis each corresponding to the single scanning with the ultrasound beam from the plurality of times of the scanning with the ultrasound beam, and determines whether or not the scanning of the bladder B of the subject S with the ultrasound beam is successful on each of the estimated sections T5to T8. Accordingly, for example, even in a case where the change in feature value is discontinuous in the ultrasound images U1or U2of the plurality of frames acquired while the plurality of times of the scanning with the ultrasound beam are performed, it is possible to measure the urine volume in the bladder B of the subject S using only the ultrasound images U1or U2of a plurality of frames where the bladder region BR1or BR2is clearly visualized.

In Embodiment 2, although the scanning success/failure determination unit12determines whether or not the scanning of the bladder B of the subject S with the ultrasound beam is successful based on the change in area of the bladder region BR1or BR2in the ultrasound image U1or U2between the frames continuous in time series, the scanning success/failure determination unit12may determine whether or not the scanning with the ultrasound beam is successful based on the inter-center-of-gravity distance LG of the bladder region BR1or BR2between the frames continuous in time series. The scanning success/failure determination unit12may determine whether or not the scanning with the ultrasound beam is successful based on the ratio of the area of the region RB where the bladder regions BR1or BR2overlap each other between the frames continuous in time series to the area of the region RA occupied by at least one of the bladder regions BR1or BR2. Even in such cases, it is possible to measure the urine volume in the bladder B of the subject S using only the ultrasound images U1and U2of the plurality of frames where the bladder region BR1or BR2is clearly visualized.

As the bladder B is regarded as the ellipsoid E shown inFIG. 9, the volume of the bladder B of the subject S is calculated based on the maximum diameters of the bladder B in the lateral direction D1, the longitudinal direction D2, and the depth direction of the subject S corresponding to the maximum diameter LX in the X direction, the maximum diameter LY in the Y direction, and the maximum diameter LZ in the Z direction of the ellipsoid E. Thus, in a case where the scanning with the ultrasound beam is performed, to measure the maximum diameter of the bladder B in the lateral direction D1, the longitudinal direction D2, and the depth direction of the subject S with excellent accuracy and to calculate the volume of the bladder B with excellent accuracy, as shown inFIG. 4, it is desirable that the ultrasound probe2is positioned directly above the center C of the bladder B of the subject S.

In this way, in a case where the ultrasound probe2is positioned directly above the center of the bladder B of the subject S, and the ultrasound probe2is tilted at a constant speed over the given angle range A, for example, the area of the bladder region BR1or BR2calculated as the feature value by the feature value calculation unit11in the ultrasound images U1or U2of the plurality of frames has symmetry in a time axis direction as shown inFIG. 24. For this reason, in a case where a distribution of the feature values in the ultrasound images U1or U2of the plurality of frames with respect to the time axis has symmetry in the time axis direction, determination can be made that the ultrasound probe2is positioned directly above the center C of the bladder B of the subject S.

In Embodiments 1 and 2, although the scanning success/failure determination unit12determines whether or not the scanning of the bladder B of the subject S with the ultrasound beam is successful depending on whether or not the feature value, such as the area of the bladder region BR1or BR2, calculated by the feature value calculation unit11in the ultrasound images U1or U2of the plurality of frames is continuous in time series, the scanning success/failure determination unit12can further determine whether or not the distribution of the feature values in the ultrasound images U1and U2of the plurality of frames with respect to the time axis has symmetry with respect to the time axis direction, and can determine whether or not the scanning with the ultrasound beam is successful in consideration of the symmetry of the feature values in the ultrasound images U1or U2of the plurality of frames with respect to the time axis.

For example, in a case where the feature value calculation unit11calculates the area of the bladder region BR1or BR2in the ultrasound images U1or U2of the plurality of frames as the feature value, as shown inFIG. 24, the scanning success/failure determination unit12detects minimum values P6and P7smaller than a given threshold value H4and detects a maximum value MP1greater than a given threshold value H5in the area of the bladder region BR1or BR2. The scanning success/failure determination unit12acknowledges that the distribution of the areas of the bladder region BR1or BR2in the ultrasound images U1or U2of the plurality of frames has symmetry in the time axis direction in a case where a duration of a section T9between a position on the time axis indicating the minimum value P6and a position on the time axis indicating the maximum value MP1is equal to a duration of a section T10between a position on the time axis indicating the maximum value MP1and a position on the time axis indicating the minimum value P7, and acknowledges that the distribution of the areas of the bladder region BR1or BR2in the ultrasound images U1or U2of the plurality of frames is asymmetrical in the time axis direction in a case where the duration of the section T9is different from the duration of the section T10.

Here, the state in which the duration of the section T9is equal to the duration of the section T10means that the duration of the section T9substantially coincides with the duration of the section T10. That is, in a case where the difference between the duration of the section T9and the duration of the section T10is within a given range, this means that the duration of the section T9is equal to the duration of the section T10. In a case where the difference between the duration of the section T9and the duration of the section T10is outside the given range, this means that the duration of the section T9is different from the duration of the section T10.

In an example shown inFIG. 24, the duration of the section T9is equal to the duration of the section T10, and thus, the scanning success/failure determination unit12acknowledges that the distribution of the areas of the bladder region BR1or BR2in the ultrasound images U1or U2of the plurality of frames has symmetry in the time axis direction. In a case where the area of the bladder region BR1or BR2in the ultrasound images U1or U2of the plurality of frames is continuous with respect to the time axis, the scanning success/failure determination unit12determines that the scanning of the bladder B of the subject S with the ultrasound beam is successful.

In this case, the maximum diameter of the bladder region BR1or BR2is calculated from the ultrasound images U1or U2of the plurality of frames that are acquired by the image acquisition unit8in a state in which the ultrasound probe2is positioned directly above the center C of the bladder B of the subject S and in which the bladder B of the subject S is clearly visualized, and the volume of the bladder B of the subject S is measured as the urine volume in the bladder B based on the measured maximum diameter of the bladder region BR1or BR2. Thus, the measurement accuracy of the urine volume is improved.

Even in a case where the distribution of the area of the bladder region BR1or BR2in the ultrasound images U1or U2of the plurality of frames is acknowledged to have symmetry in the time axis direction, for example, in a case where there is a change point where the area of the bladder region BR1or BR2in the ultrasound images U1or U2of the plurality of frames changes extremely, the scanning success/failure determination unit12determines that the scanning with the ultrasound beam fails.

As shown inFIG. 25, in a case where the ultrasound probe2is disposed at a position deviating from directly above the center of the bladder B of the subject S, and the ultrasound probe is tilted at a constant speed over the given angle range A, the distribution of the areas of the bladder region BR1or BR2calculated as the feature value by the feature value calculation unit11in the ultrasound images U1and U2of the plurality of frames is asymmetrical in the time axis direction as shown inFIG. 26.

In an example shown inFIG. 26, a duration of a section T11between a position on the time axis indicating minimum value P8of the area of the bladder region BR1or BR2smaller than the given threshold value H4and a position on the time axis indicating a maximum value MP2of the area of the bladder region BR1or BR2greater than the given threshold value H5is different from a duration of a section T12between the position on the time axis indicating the maximum value MP2and a position on the time axis indicating a minimum value P9of the area of the bladder region BR1or BR2smaller than the given threshold value H4. For this reason, the scanning success/failure determination unit12does not acknowledge that the distribution of the areas of the bladder region BR1or BR2in the ultrasound images U1or U2of the plurality of frames has symmetry in the time axis direction, and determines that the scanning of the bladder B of the subject S with the ultrasound beam fails.

From the above description, with the ultrasound diagnostic apparatus according to Embodiment 3 of the invention, the scanning success/failure determination unit12determines whether or not the scanning of the bladder B of the subject S with the ultrasound beam is successful further in consideration of the symmetry of the distribution of the feature values in the ultrasound images U1or U2of the plurality of frames in the time axis direction. Thus, it is possible to further improve the measurement accuracy of the urine volume in the bladder B of the subject S.

In Embodiment 3, although the scanning success/failure determination unit12determines that the ultrasound probe2is positioned directly above the center C of the bladder B of the subject S in a case where the distribution of the feature values with respect to the time axis is acknowledged to have symmetry in the time axis direction, and determines that the ultrasound probe2is positioned at a position deviating from directly above the center C of the bladder B of the subject S in a case where the symmetry of the distribution of the feature values with respect to the time axis is not acknowledged, a method of determining whether or not the ultrasound probe2is positioned directly above the center C of the bladder B of the subject S is not limited thereto.

FIG. 27shows the configuration of an ultrasound diagnostic apparatus1A according to Embodiment 4 of the invention. The ultrasound diagnostic apparatus1A is different from the ultrasound diagnostic apparatus1of Embodiment 1 shown inFIG. 1in that a scanning success/failure determination unit12A is provided instead of the scanning success/failure determination unit12, an apparatus controller16A is provided instead of the apparatus controller16, and a tilt angle sensor2B, a target distance estimation unit25, and a probe movement guidance unit26are newly added.

In the ultrasound diagnostic apparatus1A, the tilt angle sensor2B is incorporated in the ultrasound probe2, and the scanning success/failure determination unit12A and the target distance estimation unit25are connected to the tilt angle sensor2B. The feature value calculation unit11and the probe movement guidance unit26are connected to the target distance estimation unit25. The display controller6is connected to the probe movement guidance unit26.

The display controller6, the image acquisition unit8, the bladder extraction unit10, the feature value calculation unit11, the scanning success/failure determination unit12A, the maximum diameter measurement unit13, the notification unit14, the bladder volume calculation unit15, the apparatus controller16A, the target distance estimation unit25, and the probe movement guidance unit26configure a processor19A.

The tilt angle sensor2B measures the tilt angle W of the ultrasound probe2shown inFIGS. 4 and 5. For example, the tilt angle sensor2B includes a so-called gyro sensor, an acceleration sensor, a magnetic sensor, and the like, and converts electrical signals obtained from the gyro sensor, the acceleration sensor, the magnetic sensor, and the like into the tilt angle W of the ultrasound probe2using a known calculation method or the like. Here, it is assumed that the tilt angle W of the ultrasound probe2indicates 0 degrees in the ultrasound probe2in a state in which a direction normal to the transducer array2A is directed in a direction perpendicular to the body surface of the subject S, and has a greater value as the ultrasound probe2is tilted from the state.

The tilt angle sensor2B is incorporated in the ultrasound probe2, but may be mounted on the ultrasound probe2instead of being incorporated in the ultrasound probe2.

Here, as shown inFIG. 4, in a case where the ultrasound probe2is positioned directly above the center C of the bladder B of the subject S, the feature value, such as the area or the diameter of the bladder region BR1or BR2, calculated by the feature value calculation unit11is maximized in a state in which the direction normal to the transducer array2A at the center of the transducer array2A of the ultrasound probe2is directed in the direction perpendicular to the body surface of the subject S. For this reason, for example, at a time at which the tilt angle of the ultrasound probe2measured by the tilt angle sensor2B is 0 degrees, determination can be made whether or not the ultrasound probe2is positioned directly above the center C of the bladder B of the subject S depending on whether or not the feature value, such as the area or the diameter of the bladder region BR1or BR2, is maximized.

Accordingly, the scanning success/failure determination unit12A determines whether or not the scanning of the bladder B of the subject S with the ultrasound beam is successful in consideration of a relationship between the tilt angle W of the ultrasound probe2measured by the tilt angle sensor2B and the distribution of the feature values calculated by the feature value calculation unit11in the ultrasound images U1or U2of the plurality of frames with respect to the time axis. For example, in a case where the feature value calculation unit11calculates the area of the bladder region BR1or BR2in the ultrasound images U1or U2of the plurality of frames as the feature value, the scanning success/failure determination unit12A determines that the scanning with the ultrasound beam is successful in a case where the difference value of the areas of the bladder region BR1or BR2between any frames continuous in time series is smaller than the given threshold value, and as shown inFIG. 28, a position where the area of the bladder region BR1or BR2indicates the maximum value is acknowledged to coincide with a position where the tilt angle W measured by the tilt angle sensor2B indicates the minimum value, on the time axis.

In an example shown inFIG. 28, at a time Q1and a time Q3, the area of the bladder region BR1or BR2has a minimum value and the tilt angle W of the ultrasound probe2has a maximum value. At a time Q2, the area of the bladder region BR1or BR2has a maximum value MP3and the tilt angle W of the ultrasound probe2has a minimum value A1.

Here, the state in which the position where the area of the bladder region BR1or BR2indicates the maximum value coincides with the position where the tilt angle W measured by the tilt angle sensor2B indicates the minimum value means that the position where the area of the bladder region BR1or BR2indicates the maximum value substantially coincides with the position where the tilt angle W measured by the tilt angle sensor2B indicates the minimum value. That is, in a case where a time interval corresponding to a section between the position where the area of the bladder region BR1or BR2indicates the maximum value and the position where the tilt angle W measured by the tilt angle sensor2B indicates the minimum value is within a given range, this means that the position where the area of the bladder region BR1or BR2indicates the maximum value coincides with the position where the tilt angle W measured by the tilt angle sensor2B indicates the minimum value. In a case where a time interval corresponding to a section between the position where the area of the bladder region BR1or BR2indicates the maximum value and the position where the tilt angle W measured by the tilt angle sensor2B indicates the minimum value is outside the given range, this means that the position where the area of the bladder region BR1or BR2indicates the maximum value does not coincide with the position where the tilt angle W measured by the tilt angle sensor2B indicates the minimum value.

For example, while the difference value of the areas of the bladder region BR1or BR2in at least one frame continuous in time series is equal to or greater than the given threshold value, as shown inFIG. 29, in a case where the position where the area of the bladder region BR1or BR2indicates the maximum value is not acknowledged to coincide with the position where the tilt angle W measured by the tilt angle sensor2B indicates the minimum value, on the time axis, the scanning success/failure determination unit12A determines that the scanning with the ultrasound beam fails.

In an example shown inFIG. 29, a time Q4at which the area of the bladder region BR1or BR2has a maximum value MP4does not coincide with a time Q at which the tilt angle W of the ultrasound probe2has a minimum value A2.

The target distance estimation unit25estimates a distance between the center C of the bladder B of the subject S and the contact position of the ultrasound probe2with the subject S in a direction along the body surface of the subject S based on an ultrasound image of a frame representing a tomographic plane passing through the center C of the bladder B of the subject S among the ultrasound images U1or U2of the plurality of frames acquired by the image acquisition unit8and the tilt angle W of the ultrasound probe2measured by the tilt angle sensor2B.

For example, as shown inFIG. 30, the target distance estimation unit25selects a frame where the area or the diameter of the bladder region BR1in the ultrasound image U1is maximized, among the ultrasound images U1of the plurality of frames as a frame where a scanning plane PS3from the ultrasound probe2passes through the center C of the bladder B of the subject S, that is, an ultrasound image representing the tomographic plane passing through the center C of the bladder B of the subject S. The target distance estimation unit25measures a distance DC1between the contact position of the ultrasound probe2with the subject S and the center C of the bladder B of the subject S from the ultrasound image of the selected frame.

The target distance estimation unit25can estimate a distance DC2between the center C of the bladder B of the subject S and the contact position of the ultrasound probe2with the subject S in the direction along the body surface of the subject S, that is, the distance DC2between the contact position of the ultrasound probe2with the subject S and the position directly above the bladder B of the subject S by calculating DC1×sin(W) using the measured distance DC1and the tilt angle W of the ultrasound probe2measured by the tilt angle sensor2B.

The probe movement guidance unit26guides the user to position the ultrasound probe2directly above the center C of the bladder B of the subject S by moving the ultrasound probe2along the body surface of the subject S by the distance DC2estimated by the target distance estimation unit25. For example, as shown inFIG. 31, the probe movement guidance unit26can display information for moving the ultrasound probe2along the body surface of the subject S by the distance estimated by the target distance estimation unit25on the display unit7. In an example shown inFIG. 31, a guide panel G3including text data “Please move probe to left by XX cm.” is displayed on the display unit7to be superimposed on the ultrasound image U1.

Though not shown, in a case where the ultrasound diagnostic apparatus1A comprises a speaker, the probe movement guidance unit26can perform guidance to the user by voice through the speaker.

From the above description, with the ultrasound diagnostic apparatus1A according to Embodiment 4, determination is made whether or not the scanning of the bladder B of the subject S with the ultrasound beam is successful in consideration of whether or not a position where a feature value calculated by the feature value calculation unit11indicates an extreme value coincides with a position where the tilt angle W measured by the tilt angle sensor2B indicates an extreme value, on the time axis. Thus, it is possible to further improve the measurement accuracy of the urine volume in the bladder B of the subject S.

In a case where the position where the feature value calculated by the feature value calculation unit11indicates the extreme value does not coincide with the position where the tilt angle W measured by the tilt angle sensor2B indicates the extreme value, on the time axis, the target distance estimation unit25estimates the distance DC2between the contact position of the ultrasound probe2with the subject S and the position directly above the bladder B of the subject S, and the probe movement guidance unit26guides the user to move the ultrasound probe2along the body surface of the subject S by the estimated distance DC2based on the estimated distance DC2. Thus, the user easily disposes the ultrasound probe2at the position directly above the bladder B of the subject S, whereby it is possible to further improve the measurement accuracy of the urine volume in the bladder B of the subject S.

Although the ultrasound diagnostic apparatus1according to Embodiment 1 has a configuration in which the ultrasound probe2, the display unit7, and the input device17are connected directly to the processor19, for example, the ultrasound probe2, the display unit7, and the input device17may be connected directly through a network.

As shown inFIG. 32, an ultrasound diagnostic apparatus1B according to Embodiment 5 has a configuration in which the ultrasound probe2, the display unit7, and the input device17are connected to a diagnostic apparatus body BD through a network NW. The diagnostic apparatus body BD has a configuration in which the ultrasound probe2, the display unit7, and the input device17are removed in the ultrasound diagnostic apparatus1of Embodiment 1 shown inFIG. 1.

Here, in a case where the ultrasound beam is transmitted from the transducer array2A of the ultrasound probe2into the subject S in a case where the ultrasound probe2is pressed to the subject S by the user, the transducer array2A receives an ultrasound echo reflected inside the subject S and generates a reception signal. The ultrasound probe2transmits the generated reception signal to the diagnostic apparatus body BD through the network NW. The image acquisition unit8of the processor19of the diagnostic apparatus body BD receives the reception signal transmitted from the ultrasound probe2in this manner through the network NW, and the image acquisition unit8generates an ultrasound image U1or U2based on the reception signal.

The ultrasound image U1or U2generated by the image acquisition unit8is sent to the display controller6and the image memory9. The display controller6executes predetermined processing on the ultrasound image U1or U2received from the image acquisition unit8and further transmits the ultrasound image U1or U2subjected to the predetermined processing to the display unit7through the network NW. In this manner, the display unit7receives and displays the ultrasound image U1or U2transmitted from the display controller6of the processor19of the diagnostic apparatus body BD through the network NW.

The bladder extraction unit10of the processor19extracts a bladder region BR1or BR2representing the bladder B of the subject S from the ultrasound images of a plurality of frames stored in the image memory9.

The feature value calculation unit11calculates a feature value, such as the area of the bladder region BR1or BR2, representing the feature of the bladder region BR1or BR2extracted by the bladder extraction unit10in the ultrasound images U1or U2of the plurality of frames.

The scanning success/failure determination unit12determines whether or not scanning of the bladder B of the subject S with an ultrasound beam is successful based on the feature value calculated by the feature value calculation unit11in the ultrasound images U1and U2of the plurality of frames.

The maximum diameter measurement unit13measures the maximum diameter of the bladder region BR1or BR2from the ultrasound images U1or U2of the plurality of frames stored in the image memory9in a case where the scanning success/failure determination unit12determines that the scanning with the ultrasound beam is successful.

The bladder volume calculation unit15calculates the volume of the bladder B of the subject S as the urine volume of the bladder B based on the maximum diameter of the bladder region BR1or BR2measured by the maximum diameter measurement unit13. Information representing the urine volume in the bladder B calculated in this manner is sent to the display controller6, and is further transmitted from the display controller6to the display unit7through the network NW. The display unit7receives and displays information representing the urine volume in the bladder B of the subject S.

As described above, with the ultrasound diagnostic apparatus1B according to Embodiment 5 of the invention, even in a case where the ultrasound probe2, the display unit7, the input device17, and the diagnostic apparatus body BD are connected through the network NW, similarly to the ultrasound diagnostic apparatus1of Embodiment 1, the scanning success/failure determination unit12determines whether or not the scanning of the bladder B of the subject S with the ultrasound beam is successful. Thus, the urine volume in the bladder B of the subject S is measured using only the ultrasound image U1or U2of the frames where the scanning with the ultrasound beam is successful, and the measurement accuracy of the urine volume in the bladder B can be improved.

The ultrasound probe2, the display unit7, and the input device17are connected to the diagnostic apparatus body BD through the network, and thus, the diagnostic apparatus body BD can be used as a so-called remote server. With this, the user can perform ultrasonography of the subject S by preparing only the ultrasound probe2, the display unit7, and the input device17at hand, and thus, convenience in ultrasonography can be improved.

For example, in a case where a portable thin computer, called a tablet, is used as the display unit7and the input device17, it is possible to allow the user to more easily perform ultrasonography of the subject S, and to further improve convenience in ultrasonography.

Although the ultrasound probe2, the display unit7, and the input device17are connected to the diagnostic apparatus body BD through the network NW, the ultrasound probe2, the display unit7, the input device17, and the diagnostic apparatus body BD may be connected to the network NW in a wired manner or a wireless manner.

Although an example where the aspect of Embodiment 5 is applied to Embodiment 1 has been described, the aspect of Embodiment 5 can be similarly applied to Embodiments 2, 3, and 4.

EXPLANATION OF REFERENCES