Ultrasound measurement device

Abstract

An ultrasound measurement device includes an array of a plurality of ultrasound sensor elements, each of which includes a transmission surface through which an ultrasound beam is transmitted and a housing that includes a reference surface and a plurality of holding portions each holding a corresponding one of the ultrasound sensor elements. The ultrasound sensor elements are arranged so that a projection thereof onto a plane parallel to the reference surface forms a two-dimensional array. At least two transmission surfaces of the ultrasound sensor elements face different directions such that a scan area defined by ultrasound beams transmitted from the ultrasound sensor elements is wider in both of vertical and horizontal directions than when the transmission surfaces of the ultrasound sensor elements face the same direction.

Description

ULTRASOUND MEASUREMENT DEVICECROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to U.S. Provisional Patent Applications No. 63 / 510,149 filed June 26, 2023 and No. 63 / 597,314 filed November 8, 2023, which are herein incorporated by reference in their entirety.TECHNICAL FIELD

[0002] Embodiments of the present disclosure generally relate to an ultrasound measurement device.BACKGROUND

[0003] Ultrasound technology is widely used in a medical setting. Compared to other imaging technologies, such as X-ray and computed tomography (CT), the measurement devices using ultrasound technology have simple mechanisms and can be portable for easy measurements. Typically, such ultrasound measurement devices are used to measure an internal organ of a patient, such as a bladder.

[0004] Ultrasound measurement devices used in a medical setting have an array of transducer or ultrasound sensor elements to obtain a wide imaging range. It is desirable for such a sensor array to be able to cover a wider range with smaller components to downsize the measurement device.SUMMARY

[0005] One embodiment provides an ultrasound measurement device that includes an array of a plurality of ultrasound sensor elements, each of which includes a transmission surface through which an ultrasound beam is transmitted and a housing that includes a reference surface and a plurality of holding portions each holding a corresponding one of the ultrasound sensor elements. The ultrasound sensor elements are arranged so that a projection thereof onto a plane parallel to the reference surface forms a two-dimensional array. At least two transmission surfaces of the ultrasound sensor elements face different directions such that a scan area defined by ultrasound beams transmitted from the ultrasound sensor elements is wider in both of vertical and horizontal directions than when the transmission surfaces of the ultrasound sensor elements face the same direction.

[0006] With this configuration, the ultrasound measurement device can measure an internal organ of a patient effectively with a small array or a small number of sensorelements. This configuration enables the ultrasound measurement device to be downsized and wearable. As a result, the patient can wear the ultrasound measurement device for measuring and monitoring the internal organ for a specified time period.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is a perspective view of an ultrasound measurement device according to one embodiment.

[0008] FIG. 2 is a perspective view of each component of the ultrasound measurement device.

[0009] FIG. 3 depicts an ultrasound sensor array of the ultrasound measurement device.

[0010] FIG. 4 is a hardware block diagram of an ultrasound measurement system according to one embodiment.

[0011] FIG. 5 is a schematic block diagram of the ultrasound measurement device according to one embodiment.

[0012] FIGS. 6 through 8 depict ultrasound sensor elements disposed at certain angles.

[0013] FIGS. 9 and 10 depict a scan area of an ultrasound sensor array.

[0014] FIGS. 11 and 12 depict ultrasound beams emitted from the ultrasound sensor elements.

[0015] FIGS. 13 through 15 depict holding portions for holding the ultrasound sensor elements.

[0016] FIG. 16 is a perspective view of a pad of the ultrasound measurement device.

[0017] FIGS. 17 through 20 depict variations of the pad.

[0018] FIGS. 21 and 22 depict the ultrasound measurement device with a mounting structure.

[0019] FIG. 23 is a perspective view of an ultrasound measurement device according to another embodiment.

[0020] FIG. 24 is a flowchart of an algorithm for evaluating a bladder volume.

[0021] FIG. 25 depicts an ultrasound sensor array according to another embodiment.

[0022] FIG. 26 depicts ultrasound beams emitted from the ultrasound sensor array.

[0023] FIG. 27 depicts transmission surfaces of ultrasound sensor elements accordingto another embodiment.

[0024] FIG. 28 depicts an ultrasound sensor array according to another embodiment.

[0025] FIG. 29 is a schematic diagram of ultrasound beams emitted from the ultrasound sensor array to a target organ.DETAILED DESCRIPTION

[0026] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In order to facilitate description, dimensional ratios in the drawings are exaggerated, and thus are different from actual ratios in some cases.

[0027] FIG. 1 and FIG. 2 are perspective views of an ultrasound measurement device 10 according to one embodiment. The measurement device 10 comprises a housing 100 that includes a transducer or ultrasound sensor array 110 (hereinafter simply referred to as the array 110), a controller 200 for controlling the array 110 and processing measurement data, and a pad 400 that is held by a frame 300 to contact a skin of a patient. For example, the controller 200 controls the array 110 to emit ultrasound beams towards a target organ of the patient, and execute various processes based on the echo signals for medical diagnosis. In one embodiment, the ultrasound measurement device 10 is wearable so that the pad 400 can continue to contact a skin of a wearer, i.e., a patient. The structure for attaching the ultrasound measurement device 10 to the wearer is described later.

[0028] As shown in FIG. 1 and FIG. 2, the housing 100 has a flat reference surface RS facing a target organ and a curved surface CS along which the array 110 is formed. The array 110 includes two or more transducer or ultrasound sensor elements 130 (hereinafter simply referred to as the elements 130), which are respectively held by holding portions 120 arranged along the curved surface CS.

[0029] In the example shown in FIG. 1, the housing 100 has both the flat reference surface RS and the curved surface CS, but the housing 100 may have only the curved surface CS. In such a case, the reference surface RS referred to in this disclosure means a plane that should face a patient when the measurement is performed. For example, the plane extends along an interface between the controller 200 and the housing 100 or the housing 100 and the frame 300. The plane may extend perpendicular to a direction that the central element 130 of the array 110 faces.

[0030] FIG. 3 shows three views of the array 110, i.e., a top view and two cross sectional views along the horizontal and vertical directions in the top view. As shownin FIG. 3, the central portion of the array 110 protrudes more than the edge portion thereof from the reference surface RS. In one embodiment, one of the vertical and horizontal curvatures can be greater than the other. Since the transmission surfaces 130S of the elements 130 are arranged or substantially arranged along the curved surface CS, the elements 130 can emit the ultrasound beams in different directions, and thus achieving a wider signal coverage compared to a conventional flat sensor array.

[0031] In one embodiment, the vertical curvature of the curved surface CS is greater than the horizontal curvature. As a result, the scan angle of the elements 130 in the vertical direction becomes greater than the scan angle of the elements 130 in the horizontal direction. For example, the difference of the scan angles is a range of 5 to 100 degrees. This is suitable for measuring an internal organ located in a lower body such as a bladder.

[0032] The pad 400 is, for example, a gel pad that has a wedge shape and includes a contact surface 400S that is inclined with respect to the reference surface RS. Because of this angle, when the contact surface 400S contacts a skin of a patient, the array 110 can face the target organ. In the example shown in FIG. 1 and FIG. 2, the contact surface 400S enables the array 110 to face an internal organ in a lower body such as a bladder. In one embodiment, the pad 400 is formed of a transparent or non-transparent, soft material such as silicone such that the coverage of the ultrasound beams can be enhanced due to the refraction thereof. In another embodiment, the pad 400 has a cuboid shape and does not have any inclined surface. The details and variations of the pad 400 will be described later.

[0033] FIG. 4 is a hardware block diagram of an ultrasound measurement system 1 according to one embodiment. In this embodiment, the ultrasound measurement system 1 includes the measurement device 10 and an external device 20 such as a smartphone or a computer. The controller 200 of the measurement device 10 includes a processing module 201, an accelerometer 204, a memory 205, a pulser 206, a multiplexer (MUX) 207, a receive amplifier 208, and an analog-to-digital converter (ADC) 209. Some of the components of the measurement device 10 are not shown in FIG. 4.

[0034] The processing module 201 includes a processor 202 for controlling each component of the controller 200 and a network interface (I / F) 203 for transmitting and receiving data to and from the external device 20. For example, the network I / F 203 is a wireless communication module such as a Bluetooth® module. During imaging operation, the processing module 201 controls the pulser 206 to generate pulses, which are multiplexed by the MUX 207 and emitted from the array 110 towards a target organas ultrasound beams. Upon receipt of echo signals by the array 110, those signals are amplified by the receive amplifier 208 and converted into digital signals by the ADC 209. The processing module 201 then processes the digital signals to generate echo images of the target organ. The generated images are stored in the memory 205 and / or transmitted to the external device 20. Generating the echo image or the image of the bladder may not only be generating an actual image to be displayed, but also be detecting of the walls or boundaries of the bladder from the reflected or echoed signals called A-mode signals, e.g. signal profiles. The detected walls or boundaries of the bladder show locations of the walls or boundaries of the bladder which can be displayed as a 3D image of the bladder, e.g., by volume rendering. Therefore, the term “image” in this invention includes a set of such detected walls or boundaries of the bladder from the signal profiles of the reflected echoes.

[0035] For example, the measurement device 10 is worn by a patient to monitor the change in a volume of the bladder and measure a urine volume therein. In such a case, the processor 202 calculates the volume of the bladder using the echo signals reflected by the bladder. The processor 202 controls the accelerometer 204 to detect the orientation change and starts measurement based on the output signal from the accelerometer 204. The processor 202 can also utilize the orientation and motion data to increase the accuracy of the volume estimates.

[0036] In one embodiment, the controller 200 is battery driven such that the measurement device 10 can be worn for a certain time period. To achieve this, the controller 200 further includes a charge management circuit 211, a charger I / F 212, a lamp 213 , a battery protection circuit 214, and a battery 215. The charge management circuit 211 detects power supplied from outside via the charger I / F 212 and manages charging operations for the battery 215. The charge management circuit 211 turns on the lamp 213 when the battery 215 is being charged. The battery protection circuit 214 protects the battery 215 from over-discharge and excessive charge or discharge currents. The charge management circuit 211 outputs a signal indicating a status of the battery 215, e.g., a battery charge level and a charging status, to the processing module 201. The controller 200 further includes a power regulation circuit 216 to regulate power to be supplied to the components of the controller 200. That is, the power regulation circuit 216 regulates power supplied from the battery 215 to provide correct power to the components of the controller 200.

[0037] One or more of the components shown in FIG. 4 may be omitted depending on the design of the ultrasound measurement system 1. For example, the memory 205 canbe omitted or embedded in the processing module 201. In such a case, image data is stored in an external memory. The lamp 213 can also be omitted when no visual indication for charging operations is necessary. The controller 200 may be connected to the external device 20 by wire. In such a case, the network I / F 203 can be any type of network interface circuit that allows the external device 20 to connect to the controller 200.

[0038] FIG. 5 is a schematic block diagram of the measurement device 10 according to another embodiment. For example, the measurement device 10 is used for measuring a target organ of a patient at time of need, e.g., during regular rounds in a hospital. The measurement device 10 need not to be wearable unlike the example shown in FIG. 4. In this embodiment, the measurement device 10 includes a sensor array module 221, a power supply 222, an isolation module 223, and a control device 224, each of which is an independent device or module with its own housing.

[0039] The sensor array module 221 includes the array 110 and is put on a skin of a patient for scanning an internal organ. For example, the sensor array module 221 further includes the above-described pulser 206, the MUX 207, the receive amplifier 208, and the ADC 209 so that the ultrasound signals can be emitted from the array 110 according to the instructions from the control device 224. The power supply 222 supplies power to the sensor array module 221. The isolation module 223 connects the power supply 222 to the sensor array module 221 and connects the sensor array module 221 to the control device 224. The isolation module 223 conveys the power supplied from the power supply 222 to the sensor array module 221 while protecting an operator of the measurement device 10 (e.g., a medical personnel) and equipment from electric shock. The isolated power supply 222 also protects the operator and equipment from potential power surge and electric shock. The control device 224 has the same function as the processing module 201 or the processor 202 to control the array 110 and collect data.

[0040] The control device 224 is, for example, a computer or a mobile terminal such as a smartphone or a tablet terminal. Any wireless communication technology such as Bluetooth® can be used for the sensor array module 221 and the control device 224 to communicate with each other. In such a case, the isolation module 223 need not to be connected to the control device 224.

[0041] Now the configuration of the elements 130 of the array 110 is described with reference to FIG. 6, FIG. 7, and FIG. 8. For example, the array 110 includes multiple elements 130 arranged along the horizontal and vertical directions when viewed above. In one embodiment, the total number of elements 130 is fifty-one, but embodiments ofthis disclosure are not limited thereto. Any number of elements 130 can be used in the array 110 depending on the organ to be measured by the measurement device 10.

[0042] Each of the elements 130 is, for example, a piezoelectric transducer with a diameter between 2 and 15 mm. The operating frequency of the element 130 is set to be between 0.5 and 10 MHz (e.g., 7 MHz) with a pulse repetition frequency between 500 Hz and 10,000 Hz and the total scan time below five seconds.

[0043] In one embodiment, the elements 130 are arranged in a 3 -6-7 -6-7 -6-7 -6-3 pattern as shown in FIG. 3. When the pattern is projected onto a plane, the elements 130 are arranged in a hexagonal, triangular, or rhombic lattice pattern. With this pattern, a lot of circular elements 130 can be packed in a limited space.

[0044] As illustrated in FIG. 3, the array 110 is curved in both horizontal and vertical directions such that the transmission surfaces 130S of at least two of the elements 130 face different directions. For example, the radii of the surface of the array 110 (i.e., the curved surface CS) are 80 mm in the horizontal direction and 60 mm in the vertical direction, but could vary from these specific dimensions and be larger or smaller or equal in both horizontal and vertical direction. The radii of the surface of the array 110 also do not need to be constant. The elements 130 may be arranged along an ellipsoid surface or a surface of arbitrary and varying curvature.

[0045] For the measurement device 10 to be wearable, it needs to be small and lightweight, resulting in the size of the array 110 being smaller than a target organ. Thus, the elements 130 are arranged in such a way that the smaller measurement device 10 can scan the entire volume of the target organ. The factors to be considered regarding the arrangement include: (1) how large of the area to be scanned, which dictates the angles and positions of the elements 130 (2) with what resolution, which dictates how many elements 130 should be packed into the space. The more elements 130, the higher resolution, and higher accuracy of the measurement, or the larger field of view (FOV) of the imaged area.

[0046] FIG. 6 is schematic diagram of two adjacent elements 130 that emit ultrasound beams BM from the transmission surfaces 130S towards a target organ OG, where a represents an ultrasound beam angle, represents a mounted angle of the two elements 130, L represents a length between the target organ OG and the elements 130, A represents a curvature radius of the array 110, and D represents a distance between the centers of the elements 130.

[0047] Here, a design strategy for downsizing the array 110 is described withreference to FIG. 6, FIG. 7, and FIG. 8. To downsize the array 110 effectively, the ultrasound beam angle a needs to be minimized. Increasing a diameter d of the element 130 is one way to decrease a. The choice of the diameter d to minimize a can be made using simulations.

[0048] The minimum angle between the elements 130, P, is a function of the diameter d and the radius R. One constraint of the design is that adjacent elements 130 cannot intersect one another:[Math. 1]

[0049] Using trigonometry, D is expressed as a function of R and fl'.[Math. 2]

[0050] The possible range of P can be derived by substitution:[Math. 3][Math. 4][Math. 5]

[0051] Note that this is the minimum allowable value of fl. A value higher than the minimum can be selected for other factors. For example, a larger value of fl results in a larger FOV. A larger FOV may be desirable for increasing the likelihood of imaging the entire target organ.

[0052] As described above, the elements 130 are arranged along the curved surface CS to form the array 110 according to selected parameters. FIG. 9 and FIG. 10 depict a scan area SAI defined by ultrasound beams BM transmitted from the elements 130, which is wider in both of vertical and horizontal directions than an assumed scan area SA2 defined by ultrasound beams transmitted from the elements 130 assumed to be arranged along a two-dimensional array AR when viewed from a normal line to the reference surface RS.

[0053] Overlap between beams from adjacent elements 130 may be desirable or undesirable depending on design goals. If it is desired to transmit ultrasound energy from multiple elements 130 towards a target organ OG simultaneously, overlappingbeams will cause crosstalk, with some signal irradiated from an element 130 being reflected toward an adjacent element 130, making it difficult to understand the true positions of anatomical structures. Multiple elements 130 may transmit the ultrasound beams BM1 through BM3 towards the target organ OG in sequence to prevent this crosstalk, as shown in FIG. 11.

[0054] On the other hand, as shown in FIG. 12, if one element 130 is used to transmit an ultrasound beam, but multiple elements 130 are used to receive echoes from this transmission, it may be possible to localize anatomical structures more accurately using receive beamforming. This can only be achieved if there is significant overlap between adjacent beams.

[0055] The elements 130 are disposed in the corresponding holding portions 120, which are arranged along the curved surface CS such that the transmission surface 130S of each element 130 faces the normal direction of the curved surface CS. However, the angles of the elements 130 do not need to be on the curved surface CS, as depicted in FIG. 13, FIG. 14, and FIG. 15. To illustrate this point, in FIG. 13, the elements 130 angled along the curvature are translated along their respective perpendicular axes to be lined up on a flat plane, whereas in FIG. 14, the elements 130 angled along the curvature are translated laterally in parallel to be lined up on a flat plane. FIG. 15 illustrates that the element angles do not need to be derived from the curvature but rather each element angle could be chosen to suit its purpose in aiming and measuring a target organ.

[0056] In the example shown in FIG. 13, FIG. 14, and FIG. 15, each holding portion 120 is a recess to hold a corresponding element 130 with inclining its ultrasound transmission surface 130S. This allows the array structure to be thinner than the array structure with the element 130 arranged on the curved surface CS. In one embodiment, each recess may be filled with a lens material which can conduct ultrasound from the element 130. From this, it is not necessary to prepare the pad 400 with protrusions and insert each of the protrusions into each recess.

[0057] On the other hand, there is an advantage of the arrangement of the elements 130 along the curved surface CS. If the transmission surfaces 130S of the elements 130 are arranged substantially along the outer curved surface CS of the array structure, it is not necessary to align protrusions of the pad 400 and recesses of the array structure to insert the protrusions into the recesses for the gel contacting with the transmission surfaces 130S of the elements 130, or to fill each recess with the lens material described above.

[0058] In one embodiment, unlike the examples of FIG. 13, FIG. 14, and FIG. 15, one or more of the elements 130 may protrude from the curved surface CS. In such a case, the pad 400 may have one or more recesses that fit with the protruding elements 130.

[0059] Now the pad 400 is described with reference to FIG. 16. The pad 400 is used as a coupling medium for ultrasound transmission between the scanning surface of the array 110 and a skin of a patient or wearer. Thus, the shape of the pad 400 conforms to the curvature of the array structure and the patient’s skin. The pad 400 is made of a material that transmits ultrasound beams with minimal reflection and attenuation. The pad 400 has a thickness that provides sufficient space to conform to the array 110 and the body surface and that increases the distance between the array 110 and the target organ for expanding the FOV.

[0060] The pad 400 has tunable acoustic properties governed by ratio of constituent parts. For example, the stiffness of the pad 400 can be tuned according to the ratio of constituent parts (e.g., the mineral oil / copolymer ratio). The shape of the pad 400 may have angled surfaces (e.g., wedge) to create a tilt that angles the entire array 110 to achieve better scanning angle to capture the entire target organ.

[0061] FIG. 17, FIG. 18, FIG. 19, and FIG. 20 depict various configurations for the pad 400 in contact with the housing 100 and the array 110. In all schematic side views, the pad 400 contacts a skin SK of a patient on the right side of each figure.

[0062] In one embodiment, as shown in FIG. 17, the shape of the pad 400 orients the array 110 perpendicular to the contact surface, i.e., the skin SK. In another embodiment, as shown in FIG. 18, the space tilts the array 110 such that it angles downward which may be advantageous in targeting an organ (e.g., a bladder) located below (i.e., inferior anatomically) the position of the array 110.

[0063] FIG. 19 shows the ultrasound beams BM refracting upon entering the tissue. The curvature at the interface between the array 110 and the pad 400 and the pad material may be determined based on Snell’s Law to promote the ultrasound beams to refract upon entering the tissue to enhance the FOV.

[0064] Alternatively, using the same principle of Snell’s Law, an additional layer 450 may be introduced between the pad 400 and the array 110 as depicted in FIG. 20 to create favorable refraction to enhance the FOV of the ultrasound. One possibility of the layer 450 is an acoustic lens material that is placed in front of the array 110 which produces the desired refraction of the ultrasound beams when combined with the pad 400. Another possibility of the layer 450 is an additional gel pad that produces the preferred ultrasoundbeam refraction when combined with the pad 400.

[0065] The refraction could also be used to narrow the FOV in order to enhance the resolution of the scan. Refraction could also be used to achieve more favorable ultrasound beam angles to allow the array 110 to look around obstructing anatomical structures.

[0066] FIG. 21 and FIG. 22 depict the measurement device 10 in one embodiment, which is designed to be wearable through a mounting structure 500. For example, the mounting structure 500 is a band, a strap, a belt, or a harness to be worn at the waist of the wearer such that the measurement device 10 is placed on the desired lower abdomen. The array 110 tilted by the pad 400 can transmit ultrasound beams toward a target organ such as a bladder located in the lower body.

[0067] FIG. 23 depicts the measurement device 10 in one embodiment, which has a cuboid shape in which the above-described components of the measurement device 10, i.e., the housing 100 including the array 110, the controller 200, the frame 300, and the pad 400 are incorporated. The pad 400 may or may not have the inclined contact surface 400S. The simple and compact form is more advantageous to be worn by a patient through the mounting structure 500 as shown in FIG. 21 and FIG. 22 and continuously monitor a target organ for a specified time period.

[0068] As described above, the measurement device 10 is wearable and capable of measuring an internal organ of the wearer. For example, the measurement device 10 can be used to measure a volume of the wearer’s bladder or the wearer’s urine output volume. Such a measurement device 10 can replace a conventional, urinary catheter or specimen collector that often causes infection, discomfort, pain or difficulties for patients.

[0069] When applied to urine output volume measurement, the measurement device 10 emits ultrasound beams to detect the wall of a bladder to estimate the urine volume inside the bladder. The measurement device 10 also utilizes a signal processing algorithm and built-in features such as the accelerometer 204 that can detect the orientation and the movement of the wearer, and the processor 201 that processes the data to determine the urine output volume over time. The algorithm requires a firm understanding of the anatomical and physiological characteristics of a human bladder.

[0070] FIG. 24 is a flowchart of an algorithm performed by the measurement device 10 to evaluate the bladder volume from the received ultrasound echoes in one embodiment. This is achieved using a “library” of existing bladder data to approximate the volume of the bladder being imaged. This library may be constructed frompreviously collected synthetic, in vitro and / or in vivo data with known bladder volumes. The data in the library may be compressed in a manner to extract fundamental bladder features, thus minimizing the computational time and required storage space in memory and maximizing the generalizability of the volume estimation approach.

[0071] At the beginning of the evaluation process, the processor 202 of the measurement device 10 controls the array 110 to emit ultrasound beams towards the bladder (S601). Then, using the echo signals from the bladder, the processor 202 determines the bladder wall locations (S602). During this step, the processor 202 can use a Bayesian statistical method to determine the bladder wall locations using known information about general bladder properties (e.g., a common bladder distance from the array 110, an expected bladder height, depth, and width, etc.). These properties may be extracted from the above-described data library.

[0072] After determining the bladder wall locations, the processor 202 accesses the bladder data library stored in the memory 205 or an external device through the network I / F 203 (S603), and finds matches between the determined bladder wall locations and the ones stored in the bladder data library (S604). Once the matches are found, the processor 202 determines the volume corresponding to the matched bladder wall locations (S605) as the volume of the target bladder.

[0073] The processing of the ultrasound data may include comparing ultrasound measurements to noise acquisitions assessed from the elements 130 of the measurement device 10. Bladder volume uncertainty estimates may be reported to express the accuracy of the measurements and algorithm. Multiple scans may be registered or “stitched” together to provide a more accurate depiction of the entire bladder. The latest measurement data may be used to update the known bladder information for later measurement.

[0074] Hereinafter, variations of the measurement device 10 are described. FIG. 25 and FIG. 26 show an array 110 with holding portions 120 and elements 130 arranged in a grid or lattice pattern according to another embodiment. Like the array 110 shown in FIG. 1, each element 130 is held by the holding portion 120 formed along the surface of the array 110. FIG. 26 shows a cross section A- A of the array 110 illustrated in FIG. 25. The elements 130 in the first row emit ultrasound beams downward, whereas the elements 130 in the other rows emit ultrasound beams radially like the elements 130 shown in FIG. 1. Because of this configuration, an internal organ located in a lower body such as a bladder can be scanned effectively even if the measurement device 10 contacts the body surface horizontally.

[0075] FIG. 27 and FIG. 28 depict another arrangement of the elements 130. FIG. 27 schematically shows the transmission surfaces 130S of the elements 130, and FIG. 28 shows the exterior of the array 110 with the elements 130 shown in FIG. 27. As illustrated, the transmission surfaces 130 of some elements 130 located along three sides (e.g., top, left, and right sides as shown in FIG. 27) of the array 110 face inward. The arrangement of the other elements 130 is similar to the one shown in FIG. 1. One or more of the other elements 130 may be arranged to face inward (e.g., the elements 130 in the second row and the second and sixth columns as shown in FIG. 27). This configuration can achieve wider scanning coverage even when the measurement device 10 is attached to a body surface at an improper angle. FIG. 29 shows how ultrasound beams are emitted from the elements 130 shown in FIG. 28 to a target organ. The left plane corresponds to the surface of the array 110. A darker color indicates a closer point on the target organ from the nearest beam. As illustrated in the figure, the organ can be effectively scanned by the measurement device 10 because of the orientations of the elements 130.

[0076] This disclosure describes embodiments and examples of an ultrasound measurement device to scan an internal organ of an organ effectively. The invention is not limited, however, to the precise embodiments, examples, and variations described. Various changes, modifications and equivalents can be effected by one skilled in the art without departing from the spirit and scope of the invention as defined in the accompanying claims. It is expressly intended that all such changes, modifications and equivalents which fall within the scope of the claims are embraced by the claims.

[0077] One or more embodiments are specified in the following paragraphs:1. An ultrasound measurement device comprising: an array of a plurality of ultrasound sensor elements, each of which includes a transmission surface through which an ultrasound beam is transmitted; and a housing that includes a reference surface and a plurality of holding portions each holding a corresponding one of the ultrasound sensor elements, wherein the ultrasound sensor elements are arranged in a two-dimensional array when projected onto a plane parallel to the reference surface, and at least two transmission surfaces of the ultrasound sensor elements face different directions such that a scan area defined by ultrasound beams transmitted from the ultrasound sensor elements is wider in both of vertical and horizontal directions than an assumed scan area defined by ultrasound beams transmitted from the ultrasound sensor elements assumed to be arranged in the two-dimensional array.2. The ultrasound measurement device according to paragraph 1, further comprising: amounting structure attached to the housing and attachable to a living body.3. The ultrasound measurement device according to paragraph 1, wherein a first scan angle of the ultrasound sensor elements in the vertical direction is different from a second scan angle of the ultrasound sensor elements in the horizontal direction.4. The ultrasound measurement device according to paragraph 3, wherein the first scan angle is greater than the second scan angle.5. The ultrasound measurement device according to paragraph 3, wherein an angle difference between the first and second scan angles is a range of 5 to 100 degrees.6. The ultrasound measurement device according to paragraph 1, wherein a scan angle between normal vectors of transmission surfaces of two of the ultrasound sensor elements disposed at both ends of the array in the vertical direction is larger than a scan angle between normal vectors of transmission surfaces of two of the ultrasound sensor elements disposed at both ends of the array in the horizontal direction.7. The ultrasound measurement device according to paragraph 1, wherein transmission surfaces of the ultrasound sensor elements are substantially disposed along a curved surface that has a first curvature radius in the vertical direction and a second curvature radius in the horizontal direction, and the first curvature radius is smaller than the second curvature radius.8. The ultrasound measurement device according to paragraph 1, wherein transmission surfaces of two or more of the ultrasound sensor elements arranged along the vertical or the horizontal direction face different directions.9. The ultrasound measurement device according to paragraph 1, wherein the array includes a first portion at a center thereof and a second portion surrounding the first portion, the ultrasound sensor elements include a first element disposed on the first portion and two or more second elements disposed on the second portion, and an angle between the transmission surface of the first element and each of the transmission surfaces of the second elements increases in a direction from the first portion to the second portion.10. The ultrasound measurement device according to paragraph 9, wherein the first portion protrudes more than the second portion from the reference surface.11. The ultrasound measurement device according to paragraph 1, wherein the housing includes a curved surface, the holding portions are recesses formed along the curved surface, and the transmission surfaces of the ultrasound sensor elements are arranged substantially along the curved surface.12. The ultrasound measurement device according to paragraph 1, further comprising: a pad attached to the housing and including a first surface that contacts the array and a second surface that is opposite to the second surface and inclined with respect to the first surface in the vertical direction.13. The ultrasound measurement device according to paragraph 1, further comprising: a pad attached to the housing and including a first surface that contacts the housing and a second surface that is opposite to the second surface, wherein the pad refracts the ultrasound beams in a direction from a center portion of the array to a peripheral portion thereof.14. The ultrasound measurement device according to paragraph 13, wherein the pad includes two layers formed of different materials and including a corresponding one of the first and second surfaces.15. The ultrasound measurement device according to paragraph 1, further comprising: a pad attached to the housing and including a first surface that contacts the housing and a second surface that is opposite to the second surface; and a frame attached to the housing and surrounding the pad.16. The ultrasound measurement device according to paragraph 1, wherein the ultrasound sensor elements include: a first element that projects onto a first row of the array located at an end thereof and faces a first direction, and a second element that projects onto a second row of the array adjacent to the first row and faces a second direction, and the first and second directions cross each other.17. The ultrasound measurement device according to paragraph 16, wherein the first row is located at an upper end of the array in the vertical direction.18. The ultrasound measurement device according to paragraph 16, wherein the first row is located at one end of the array in the horizontal direction, and the ultrasound sensor element include: a third element that projects onto a third row of the array located at the other end thereof in the horizontal direction and faces a third direction, and a fourth element that projects onto a fourth row of the array adjacent to the third row and faces a fourth direction, and the third and fourth directions cross each other.19. An ultrasound measurement device, comprising: a housing that includes a surface to face a living body to be measured; and a plurality of ultrasound sensor elements arranged along the surface of the housing and each including a transmission surface through which an ultrasound beam is transmitted, wherein a first transmission surface of one of the ultrasound sensor elements faces a first direction and a second transmissionsurface of another of the ultrasound sensor elements faces a second direction such that the first and second directions form a certain angle.20. The ultrasound measurement device according to paragraph 19, wherein the surface of the housing is a curved surface that has a first curvature radius in a third direction and a second curvature radius in a fourth direction perpendicular to the third direction, the first curvature radius being different from the second curvature radius.

Claims

CLAIMS1. An ultrasound measurement device comprising: an array of a plurality of ultrasound sensor elements, each of which includes a transmission surface through which an ultrasound beam is transmitted; and a housing that includes a reference surface and a plurality of holding portions each holding a corresponding one of the ultrasound sensor elements, wherein the ultrasound sensor elements are arranged so that a projection thereof onto a plane parallel to the reference surface forms a two-dimensional array, and at least two transmission surfaces of the ultrasound sensor elements face different directions such that a scan area defined by ultrasound beams transmitted from the ultrasound sensor elements is wider in both of vertical and horizontal directions than when the transmission surfaces of the ultrasound sensor elements face the same direction.

2. The ultrasound measurement device according to claim 1 , further comprising: a mounting structure attached to the housing and attachable to a living body.

3. The ultrasound measurement device according to claim 1 , wherein a first scan angle of the ultrasound sensor elements in the vertical direction is different from a second scan angle of the ultrasound sensor elements in the horizontal direction.

4. The ultrasound measurement device according to claim 3, wherein the first scan angle is greater than the second scan angle.

5. The ultrasound measurement device according to claim 3, wherein an angle difference between the first and second scan angles is a range of 5 to 100 degrees.

6. The ultrasound measurement device according to claim 1, wherein a scan angle between normal vectors of transmission surfaces of two of the ultrasound sensor elements disposed at both ends of the array in the vertical direction is larger than a scan angle between normal vectors of transmission surfaces of two of the ultrasound sensor elements disposed at both ends of the array in the horizontal direction.

7. The ultrasound measurement device according to claim 1, wherein transmission surfaces of the ultrasound sensor elements are substantially disposed along a curved surface that has a first curvature radius in the vertical direction and a second curvature radius in the horizontal direction, andthe first curvature radius is smaller than the second curvature radius.

8. The ultrasound measurement device according to claim 1, wherein transmission surfaces of two or more of the ultrasound sensor elements arranged along the vertical or the horizontal direction face different directions.

9. The ultrasound measurement device according to claim 1, wherein the array includes a first portion at a center thereof and a second portion surrounding the first portion, the ultrasound sensor elements include a first element disposed on the first portion and two or more second elements disposed on the second portion, and an angle between the transmission surface of the first element and each of the transmission surfaces of the second elements increases in a direction from the first portion to the second portion.

10. The ultrasound measurement device according to claim 9, wherein the first portion protrudes more than the second portion from the reference surface.

11. The ultrasound measurement device according to claim 1, wherein the housing includes a curved surface, the holding portions are recesses formed along the curved surface, and the transmission surfaces of the ultrasound sensor elements are arranged substantially along the curved surface.

12. The ultrasound measurement device according to claim 1, further comprising: a pad attached to the housing and including a first surface that contacts the array and a second surface that is opposite to the second surface and inclined with respect to the first surface in the vertical direction.

13. The ultrasound measurement device according to claim 1, further comprising: a pad attached to the housing and including a first surface that contacts the housing and a second surface that is opposite to the second surface, wherein the pad refracts the ultrasound beams in a direction from a center portion of the array to a peripheral portion thereof.

14. The ultrasound measurement device according to claim 13, wherein the pad includes two layers formed of different materials and including a corresponding one of the first and second surfaces.

15. The ultrasound measurement device according to claim 1, further comprising: a pad attached to the housing and including a first surface that contacts the housing and a second surface that is opposite to the second surface; and a frame attached to the housing and surrounding the pad.

16. The ultrasound measurement device according to claim 1, wherein the ultrasound sensor elements include: a first element that projects onto a first row of the array located at an end thereof and faces a first direction, and a second element that projects onto a second row of the array adjacent to the first row and faces a second direction, and the first and second directions cross each other.

17. The ultrasound measurement device according to claim 16, wherein the first row is located at an upper end of the array in the vertical direction.

18. The ultrasound measurement device according to claim 16, wherein the first row is located at one end of the array in the horizontal direction, and the ultrasound sensor element include: a third element that projects onto a third row of the array located at the other end thereof in the horizontal direction and faces a third direction, and a fourth element that projects onto a fourth row of the array adjacent to the third row and faces a fourth direction, and the third and fourth directions cross each other.

19. An ultrasound measurement device, comprising: a housing that includes a surface to face a living body to be measured; and a plurality of ultrasound sensor elements arranged along the surface of the housing and each including a transmission surface through which an ultrasound beam is transmitted, whereina first transmission surface of one of the ultrasound sensor elements faces a first direction and a second transmission surface of another of the ultrasound sensor elements faces a second direction such that the first and second directions form a certain angle.

20. The ultrasound measurement device according to claim 19, wherein the surface of the housing is a curved surface that has a first curvature radius in a third direction and a second curvature radius in a fourth direction perpendicular to the third direction, the first curvature radius being different from the second curvature radius.

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