Ultrasonic scanner and method for correcting ultrasonic signals in said ultrasonic scanner

Abstract

The present invention relates to an ultrasonic scanner. The ultrasonic scanner is a bladder scanner that uses mechanical rotation using a motor in one direction and manual rotation by an operator in the other direction. The ultrasonic scanner is configured to reduce a measurement error of the urine volume that may occur due to an undesired physical position movement of an ultrasonic transducer consisting of a single element when determining the urine volume in the bladder. The control unit of the ultrasonic scanner according to the present invention is characterized in that it receives an ultrasonic echo signal from the ultrasonic transducer, corrects coordinates for the ultrasonic echo signal considering a tilt angle of the ultrasonic probe due to manual operation, and obtains a fan-shaped two-dimensional ultrasonic image using the ultrasonic echo signal of the corrected coordinates.

Description

[Technical Field]

[0001] The present invention relates to a portable bladder scanner that uses a three-dimensional scanning ultrasound scanner to measure the volume of urine in the bladder. More specifically, the ultrasound scanner according to the present invention extracts physical position errors of the ultrasound transducer that occur during the ultrasound scanning process due to manual rotation by an operator, and uses the extracted errors to correct the coordinates of the ultrasound echo signal, thereby enabling accurate measurement of the volume of urine in the bladder. [Background technology]

[0002] Healthy individuals can sense a full bladder and spontaneously urinate when the bladder is filled with a certain amount of urine. However, patients with urinary disorders caused by various illnesses are unable to sense a full bladder, or are unable to spontaneously urinate even when they sense a full bladder. This can lead to an excessive amount of urine filling the bladder, which can lead to bladder-related complications. To care for such patients with urinary disorders, the volume of urine stored in the bladder must be measured periodically or whenever necessary. To measure a patient's urine volume, a handheld 3D ultrasound scanner is used.

[0003] In this specification, a special-purpose portable 3D ultrasound scanner for measuring the volume of urine in the bladder is referred to as a "bladder scanner." Unlike general medical ultrasound scanners, a bladder scanner's primary purpose is to measure the volume of urine in the bladder. Therefore, the primary function of a bladder scanner is to automatically segment the bladder region from a 3D ultrasound image, calculate the volume of the segmented bladder region, and numerically represent the calculated volume of the bladder region. A secondary function of a bladder scanner is to output the acquired ultrasound image to a display device. In particular, the bladder scanner is characterized by its minimized size and weight to make it portable for medical personnel. Therefore, a bladder scanner is specialized for measuring urine volume, and other secondary functions are generally omitted.

[0004] To reduce the manufacturing cost of a bladder scanner, the bladder scanner may be manufactured with a structure including a single-element ultrasound transducer and a motor for driving the transducer. Bladder scanners with this structure often use a method of scanning ultrasound beams while rotating the ultrasound transducer using a motor for fan-shaped scanning. To perform a three-dimensional ultrasound scan of the bladder, it is necessary to obtain multiple two-dimensional cross-sectional ultrasound images of the bladder by sequentially performing fan-shaped scanning of a single plane in multiple directions. To achieve this, the transducer must be scanned in two directions. To scan in two directions, two motors driven in different directions may be provided. However, ultrasound scanners with this structure have a problem in that the size and weight of the motor driving unit increase.

[0005] Therefore, a portable bladder scanner can be manufactured with a single motor to maximize its size and weight. Such a bladder scanner can be configured to rotate automatically in one direction using the motor and manually in the remaining directions using the operator's hand movements. The present invention relates to a method for reducing errors in urine volume measurement that can occur in ultrasound scanning bladder scanners that use manual rotation by the operator.

[0006] Bladder scanners are manufactured for simple measurement of bladder volume only, and are therefore characterized by their small size and low cost compared to general ultrasound scanners. To reduce the manufacturing cost of bladder scanners, they are generally equipped with a single-element ultrasound transducer. General ultrasound scanners are equipped with a phased array transducer, in which multiple transducers are arranged linearly or planarly, which makes them expensive and requires a complex driving method. Therefore, general ultrasound scanners have limitations that make them difficult to adopt as portable bladder scanners. For this reason, bladder scanners generally use a single-element ultrasound transducer. Bladder scanners using a single-element transducer require three-dimensional ultrasound scanning to obtain a volumetric image of the bladder. Bladder scanners generate three-dimensional ultrasound images using multiple two-dimensional cross-sectional ultrasound images acquired by performing multiple sector scans at multiple angles.

[0007] FIG. 1 is a structural diagram of a typical bladder scanner. Referring to FIG. 1, the typical bladder scanner 10 includes a control unit for controlling overall operation, an ultrasonic transducer 110, a first motor 120, a second motor 130, and a motor driver. The bladder scanner described above has an ultrasonic transducer 110 at its lower end. The thickness of the transducer is determined by the frequency of the ultrasound waves, which are typically around 2 to 3 MHz. The transducer is typically circular. The diameter of the transducer is determined based on the maximum depth of the bladder to be measured by ultrasound and is typically around 10 to 15 mm. The ultrasonic transducer 110 is mechanically connected to a motor driver 140. The motor driver drives the first and second motors to rotate the ultrasonic transducer in two different directions, thereby performing an ultrasound scan. The motor driver typically employs a sector scan method to acquire two-dimensional cross-sectional ultrasound images. The ultrasonic transducer 110, motor drive unit, ultrasonic drive circuit unit, etc. are disposed and fixed within a covering 140 of the bladder scanner.

[0008] Figure 2 is a schematic diagram showing the fan-shaped scanning used to rotate an ultrasonic transducer using a motor in a typical bladder scanner to acquire two-dimensional ultrasonic signals. As shown in Figure 2, when the ultrasonic transducer is rotated by an angle φ, the ultrasonic beam emitted from the transducer rotates by an angle φ with respect to the central axis y. At this time, the rotation axis of the ultrasonic transducer has a center point O on the lower end surface of the ultrasonic transducer.

[0009] 3A and 3B are diagrams illustrating the direction of rotation of the rotation axis of an ultrasound transducer in a conventional bladder scanner. When a motor driver rotates the transducer at a constant angular velocity, a fan scan as shown in FIG. 3A can be generated. In FIG. 3A, the number of scan lines is M+1, and the separation angle Δφ between adjacent scan lines is preferably constant. The angle of the fan scan must be set to scan the entire bladder, typically about 120°. One fan scan generates one two-dimensional cross-sectional image. Therefore, to obtain a three-dimensional image, fan scans must be performed repeatedly while changing the scan angle. A commonly used method is to perform fan scans as shown in FIG. 3A while rotating the transducer at a constant angular velocity around the central axis y-axis, as shown in FIG. 3B. In FIG. 3B, this rotation angle is denoted as θ. As shown in FIG. 3B, a three-dimensional scan trajectory can be generated by performing one fan scan, rotating it by Δθ, and then repeating the fan scan. By sequentially rotating the image by 180° along the θ direction, a three-dimensional volumetric image can be obtained.

[0010] Figure 4 is a schematic diagram showing the direction in which a bladder scanner equipped with two motors driven in different directions rotates to acquire a three-dimensional image. As shown in Figure 4, the bladder scanner is positioned on the patient's lower abdomen, i.e., on the surface of the abdomen where the bladder is located, and then the above-described three-dimensional scanning is performed to acquire a three-dimensional image of the area including the bladder. The three-dimensional scanning speed of a bladder scanner is much slower than that of a typical ultrasound scanner, typically on the order of a few seconds. The transducer transmits ultrasonic pulses while reciprocating at a constant angular velocity within a sector plane (S i (i = 0, 1, 2, . . . , N)) and receives ultrasonic echo signals reflected within the human body. A larger number of sector planes enables more precise three-dimensional scanning. However, a larger number of sector planes results in a longer measurement time for the bladder scanner. Therefore, the number of sector planes is typically around 10 to 20.

[0011] Thus, to perform three-dimensional scanning using a single-element ultrasound transducer, it is necessary to rotate the ultrasound transducer in two directions. Therefore, a scanning structure with two degrees of freedom is required. To achieve a scanning structure with two degrees of freedom, two motors are usually used, but this leads to the problem that the bladder scanner becomes large and heavy.

[0012] A plurality of 2D ultrasound images for different positions are acquired by performing sector scans in different directions including the bladder, and urine volume can be estimated using the acquired plurality of 2D ultrasound images. Algorithms for measuring urine volume from a plurality of 2D ultrasound images are well known, and various methods are used. In particular, urine volume measurement algorithms are specifically described in Korean Patent Nos. 10-0763453 and 10-1874613.

[0013] Ultrasonic pulses emitted from a transducer propagate through the human body, partially reflecting or scattering them and gradually attenuating their intensity. The degree to which an ultrasonic pulse is reflected or scattered is determined by the difference between the acoustic impedance of the region and the surrounding area. Typical biological tissues, such as muscle and visceral tissue, are composed of cells, so reflection and scattering occur even within the same biological tissue. However, urine in the bladder is a homogeneous liquid, with a more uniform acoustic impedance than biological tissue. Therefore, almost no reflection or scattering of ultrasound occurs within the urine. As a result, urine inside the bladder has low brightness in ultrasound images. Taking advantage of the high contrast between the urine inside the bladder and the surrounding biological tissue, a bladder region can be segmented in a 2D ultrasound image and then aligned three-dimensionally to obtain a 3D image of the bladder. Urine volume can be estimated from this 3D bladder image. As shown in Figure 3A, when performing an ultrasound scan, all scan lines for all cross sections begin at a single point O. Therefore, cross-sectional images obtained at all angles have the same magnification. That is, a cone-shaped coordinate system starting from point O can be applied to each cross-sectional image, which simplifies the calculation of urine volume.

[0014] As mentioned above, a bladder scanner can be equipped with only a single motor to reduce its size and weight. In a bladder scanner equipped with a single motor, rotation in a first direction is driven by the motor, and rotation in a second direction is performed by the operator's manual movement. Figure 5 is a schematic diagram showing rotation for acquiring a three-dimensional image in an existing bladder scanner equipped with a single motor. As shown in Figure 5, a bladder scanner equipped with a single motor can automatically rotate the transducer along the first direction using the motor to perform a fan-shaped scan while the operator manually tilts the bladder scanner along a second direction perpendicular to the first direction. The motor can generate uniform angular motion through electrical control. However, it is difficult to generate uniform angular motion when the operator manually rotates the bladder scanner. Therefore, it is necessary to attach sensors to the bladder scanner to measure the scanner angle.

[0015] After placing a bladder scanner on the surface of the human abdomen, when an operator manually rotates the scanner to perform ultrasound scanning, the starting point of the scan line does not converge to a single point. As shown in Figure 4, when the ultrasound scanner is driven by a motor, the exterior of the bladder scanner can be fixed to the surface of the patient's abdomen while scanning is performed. However, as shown in Figure 5, when the operator manually tilts the bladder scanner, the exterior surface of the bladder scanner moves along the surface of the patient's abdomen. In particular, because the surface of the probe covering, which is the exterior of the bladder scanner, and the ultrasound transducer are physically separated, the position of the ultrasound transducer moves as the bottom end of the probe covering moves. As a result, a problem occurs in that the position of the ultrasound transducer does not remain fixed but moves spatially during ultrasound scanning by manually rotating the scanner.

[0016] Therefore, when a bladder scanner acquires multiple two-dimensional ultrasound images through ultrasound scanning by manual rotation by the operator and uses these to calculate urine volume, there is a problem that errors occur due to undesired positional movement of the ultrasound transducer. Summary of the Invention [Problem to be solved by the invention]

[0017] In order to solve the above-mentioned problems, the present invention aims to provide a method that can reduce errors in measuring urine volume in a bladder scanner that uses mechanical rotation by a motor in one direction and manual rotation by an operator in the other direction.

[0018] Therefore, the bladder scanner according to the present invention is configured to correct the coordinates of the ultrasound echo signals to take into account undesired physical positional movement of the ultrasound transducer that occurs when determining the volume of urine in the bladder, and to reduce measurement errors in the urine volume through such coordinate correction. [Means for solving the problem]

[0019] According to an aspect of the present invention, there is provided an ultrasonic scanner that achieves the above-described technical objectives, comprising: an ultrasonic transducer that transmits ultrasonic signals to a measurement object and receives and provides ultrasonic echo signals reflected from the measurement object; a single motor connected to a central axis of the ultrasonic transducer; an ultrasonic probe having the ultrasonic transducer and the motor mounted therein; a tilt sensor attached to the central axis of the ultrasonic probe and that detects and provides a tilt angle of the ultrasonic probe with respect to a second direction; and a controller that acquires fan-shaped two-dimensional ultrasonic images at a plurality of tilt angles in response to a change in the tilt angle due to manual operation, the two-dimensional ultrasonic images being acquired by rotating the ultrasonic transducer along a first direction perpendicular to the second direction using the motor, wherein the controller receives ultrasonic echo signals from the ultrasonic transducer, corrects coordinates for the ultrasonic echo signals taking into account the tilt angle of the ultrasonic probe due to manual operation, and acquires the fan-shaped two-dimensional ultrasonic image using the ultrasonic echo signals of the corrected coordinates.

[0020] In the ultrasonic scanner having the above-mentioned features according to the present invention, it is preferable that the control unit comprises: a coordinate correction module that receives ultrasonic echo signals from the ultrasonic transducer and corrects coordinates of the ultrasonic echo signals in consideration of a tilt angle of the ultrasonic probe caused by manual operation; and a two-dimensional ultrasonic image acquisition module that drives a motor to rotate the ultrasonic transducer along a first direction, acquires ultrasonic echo signals in accordance with the rotational movement, corrects the coordinates of the ultrasonic echo signals using the coordinate correction module, and acquires a fan-shaped two-dimensional ultrasonic image using the ultrasonic echo signals whose coordinates have been corrected.

[0021] In the ultrasound scanner according to the above-described features, it is preferable that the control unit further includes a three-dimensional information extraction module that repeatedly drives the two-dimensional ultrasound image acquisition module in response to a change in tilt angle due to manual operation, thereby acquiring a plurality of two-dimensional ultrasound images at a plurality of tilt angles, and extracts predetermined three-dimensional information using the plurality of two-dimensional ultrasound images.

[0022] In the ultrasonic scanner according to the above-mentioned features, it is preferable that the coordinate correction module receives an ultrasonic echo signal from the ultrasonic transducer, obtains initial coordinates (x, y) for the ultrasonic echo signal based on an origin preset as a reference position of the ultrasonic transducer, calculates an error value (Δx, Δy) indicating the degree to which the ultrasonic transducer deviates from the origin using a tilt angle (θ) of the ultrasonic probe provided by the tilt sensor, corrects the initial coordinate for the ultrasonic echo signal using the error value, and provides corrected coordinates (x', y') for the ultrasonic echo signal. [Effects of the Invention]

[0023] Existing ultrasound scanners are configured to perform mechanical rotation using a motor in one direction and manual rotation by an operator in the other direction, which causes the ultrasound transducer to move away from the initial reference point, resulting in inaccurate calculation of the coordinates of the ultrasound echo signal.

[0024] Therefore, the ultrasonic scanner according to the present invention calculates an error value due to the positional deviation of the ultrasonic transducer and uses the calculated error value to correct the coordinates of the ultrasonic echo signal, thereby enabling the ultrasonic scanner according to the present invention to obtain accurate position coordinates for the ultrasonic echo signal, thereby minimizing distortion of the ultrasonic image.

[0025] Furthermore, the ultrasound scanner of the present invention can significantly reduce errors in measuring urine volume compared to conventional methods by minimizing distortion of ultrasound images. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 is a perspective view of a prior art bladder scanner configured to obtain three-dimensional images using two motors. [Figure 2] FIG. 2 is a diagram illustrating the rotation of an ultrasonic transducer for performing a sector scan in the bladder scanner of FIG. 1. [Figure 3A] FIG. 2 is a diagram showing a three-dimensional ultrasound scanning trajectory using sector scanning in the bladder scanner of FIG. 1. [Figure 3B] FIG. 2 is a diagram showing a three-dimensional ultrasound scanning trajectory using sector scanning in the bladder scanner of FIG. 1. [Figure 4] 2 is a schematic diagram showing the direction in which a motor rotates the bladder scanner of FIG. 1 to obtain a three-dimensional image. [Figure 5] FIG. 1 is a schematic diagram showing the directions in which an operator manually rotates a bladder scanner left and right in a conventional bladder scanner that obtains three-dimensional images using one motor. [Figure 6A] FIG. 6 is a diagram showing an ideal three-dimensional ultrasound scanning trajectory in the bladder scanner according to FIG. 5. [Figure 6B] FIG. 6 is a diagram showing an ideal three-dimensional ultrasound scanning trajectory in the bladder scanner according to FIG. 5. [Figure 7] 6 shows the trajectory of the ultrasound transducer in the bladder scanner of FIG. 5 when the operator tilts the bladder scanner by hand. [Figure 8] FIG. 6 is a diagram showing an actual scanning trajectory of the bladder scanner as moved by the operator's hand in the bladder scanner shown in FIG. 5. [Figure 9] 1 is a graph showing an example of an ultrasound echo signal. [Figure 10] 10 is a graph showing coordinates in a mechanical scanning method in which an ultrasonic transducer is rotated using a motor in a bladder scanner. [Figure 11] 6 is a graph showing coordinates in a scanning mode in which an operator manually rotates the bladder scanner in the bladder scanner shown in FIG. 5. [Figure 12A] 1 is a block diagram showing a schematic structure of an ultrasound scanner according to a preferred embodiment of the present invention; [Figure 12B] 1 is a block diagram showing a schematic structure of an ultrasound scanner according to a preferred embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, an ultrasonic scanner and a position correction method for the ultrasonic scanner according to preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

[0028] 12 is a block diagram showing an ultrasonic scanner according to a preferred embodiment of the present invention. Referring to FIG. 12, an ultrasonic scanner 90 according to the present invention includes an ultrasonic probe 93 and a controller 95. The ultrasonic probe 93 is equipped with a single-element ultrasonic transducer 91, a motor 92, and a tilt sensor 94. The controller is comprised of a microprocessor or the like and can be installed inside the ultrasonic probe or installed in a separate device and physically connected to the ultrasonic probe.

[0029] The ultrasonic transducer 91, which is composed of a single element, transmits an ultrasonic signal to an object to be measured and receives an ultrasonic echo signal reflected from the object to be measured. The motor 92 is connected to the central axis of the ultrasonic transducer and rotates the ultrasonic transducer along a first direction under the control of the control unit. The ultrasonic probe 93 is equipped with the ultrasonic transducer, a motor, and a tilt sensor. The tilt sensor 94 is attached to the central axis of the ultrasonic probe and detects the tilt angle of the ultrasonic probe with respect to a second direction. The second direction is perpendicular to the first direction.

[0030] The control unit 95 includes a coordinate correction module 950, a 2D ultrasound image acquisition module 952, and a 3D information extraction module 954. The control unit rotates the ultrasound transducer in a first direction using the motor to acquire a fan-shaped 2D ultrasound image. The control unit acquires a plurality of 2D ultrasound images at a plurality of tilt angles in response to changes in the tilt angle due to manual movement by the operator. The control unit extracts predetermined 3D information using the plurality of 2D ultrasound images. Here, the first direction and the second direction are perpendicular to each other. While the operator manually rotates the ultrasound probe in the second direction, the control unit drives the motor to repeatedly rotate the ultrasound transducer in the ultrasound probe in the first direction to scan and acquire a plurality of 2D ultrasound images. In particular, the control unit 95 receives ultrasound echo signals from the ultrasound transducer, corrects coordinates for the ultrasound echo signals taking into account the tilt angle of the ultrasound probe due to manual operation, and acquires a fan-shaped 2D ultrasound image using the ultrasound echo signals having the corrected coordinates.

[0031] The coordinate correction module 950 corrects a physical position error that occurs due to the physical separation between the lower end of the covering of the ultrasound probe, which contacts the measurement point, and the ultrasound transducer serving as a measurement sensor. The coordinate correction module 950 receives an ultrasound echo signal from the ultrasound transducer and obtains initial coordinates (x, y) for the ultrasound echo signal based on a preset origin as the reference position of the ultrasound transducer. Then, it calculates an error value (Δx, Δy) indicating the degree to which the ultrasound transducer deviates from the origin using the tilt angle θ of the ultrasound probe provided by the tilt sensor. Then, it corrects the initial coordinate for the ultrasound echo signal using the error value to provide corrected coordinates (x', y') for the ultrasound echo signal. The coordinates (x', y') corrected by the coordinate correction module according to the above process can be calculated using the following equation:

[0032]

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[0033]

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[0034]

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[0035]

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[0036]

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[0037] Here, (x, y) indicate the initial coordinates for the ultrasonic echo signal based on the origin, (x', y') indicate the corrected coordinates for the ultrasonic echo signal taking into account the tilt angle of the ultrasonic probe, Δd indicates the amount of axial movement of the ultrasonic probe, and R indicates the radius of the covering at the bottom end of the ultrasonic probe.

[0038] The two-dimensional ultrasound image acquisition module 952 drives a motor to rotate the ultrasound transducer along a first direction perpendicular to a second direction, acquires ultrasound echo signals according to the rotation, corrects coordinates for the ultrasound echo signals using the coordinate correction module, and acquires a fan-shaped two-dimensional ultrasound image using the ultrasound echo signals having the corrected coordinates.

[0039] The three-dimensional information extraction module 954 repeatedly drives the two-dimensional ultrasound image acquisition module in response to changes in the tilt angle caused by manual operation by the operator, thereby acquiring two-dimensional ultrasound images at multiple tilt angles. Next, the three-dimensional information extraction module 954 extracts predetermined three-dimensional information using the acquired multiple two-dimensional ultrasound images. The three-dimensional information is characterized by being urine volume calculated from the bladder volume.

[0040] The operation of the bladder scanner, which is an ultrasound scanner according to the present invention having the above-described configuration, will now be described in more detail. The bladder scanner according to the present invention performs ultrasound scanning by using a single motor to perform mechanical rotation in a first direction driven by the motor while rotating in a second direction by manual operation by an operator.

[0041] 5 is a schematic diagram showing the process of scanning while an operator manually rotates a bladder scanner having a single motor in the left and right direction according to the present invention. Referring to FIG. 5, the operator holds the bladder scanner in his / her hand and tilts it left and right to perform an ultrasound scan. The motor drive unit built into the bladder scanner performs a sectorial scan as in the conventional technology, but the sectorial scan is performed in the up and down direction.

[0042] Figures 6A and 6B show ideal three-dimensional ultrasound scan trajectories for a single-motor bladder scanner according to the present invention. When the tilt angle θ is manually rotated by the operator, a scan plane like that shown in Figure 6A is acquired. In Figure 6A, each fan-shaped scan plane is acquired by ultrasonic scanning using motor-driven rotation of the ultrasonic transducer. A set of scan planes can then be acquired by manual rotation by the operator. By representing the fan-shaped scan planes in Figure 6B as lines, a set of scan planes like that shown in Figure 6A can be obtained. In Figure 6B, one line corresponds to one scan plane in Figure 6A. The separation angle Δθ between adjacent scan planes is preferably constant. However, because it is difficult to manually rotate an ultrasound scanner at a constant angular velocity, the separation angle Δθ may vary for each scan plane. However, a volumetric ultrasound image can be obtained using the value of the separation angle Δθ. By attaching an angle sensor to the upper end of the bladder scanner, the scan angle θ when acquiring each fan-shaped scan plane can be determined, and therefore the separation angle Δθ between adjacent scan planes can also be determined.

[0043] In FIGS. 6A and 6B, each scanning plane is S i The number of scan planes is N+1. The more scan planes there are, the higher the resolution of the 3D volumetric image becomes, but the longer it takes to obtain the 3D volumetric image. Taking this into consideration, the number of scan planes is usually set to 10 to 20. In FIG. 6B, it is assumed that all scan lines originate from point O, but this is not the case in actual situations. Referring to FIG. 7, while a fan scan is performed by a motor mounted inside the probe of the bladder scanner, if the operator manually tilts the probe in a direction perpendicular to the fan scan, another fan scan is performed along the tilted direction.

[0044] Figure 7 shows the trajectory of the ultrasound transducer when the bladder scanner according to the present invention is manually tilted. Assume that a motorized fan scan is performed along the z-axis direction and the bladder scanner is manually rotated along the x-axis direction. Unlike motorized fan scans, tilting the ultrasound probe along the x-axis direction does not fix the position of the ultrasound transducer at point O but changes depending on the tilt angle θ. This is because tilting the bladder scanner causes the lower end of the hemispherical bladder scanner to move along the x-axis while maintaining contact with the surface of the patient's abdomen. In other words, the contact point between the lower end of the bladder scanner (i.e., the lower end of the covering of the ultrasound probe) and the surface of the patient's abdomen is not fixed but moves along the x-axis. It is important to maintain good contact between the lower end of the ultrasound probe and the surface of the patient's abdomen to prevent an air gap from forming. Otherwise, ultrasound waves will be excessively reflected from the air gap, making it difficult to obtain a good-quality ultrasound image.

[0045] When the operator manually tilts the bladder scanner, the transducer position not only moves in the x-axis (left and right) direction, but also changes in the y-axis (height) direction, as shown in Figure 7. This is because a certain distance is required between the ultrasound transducer and the probe covering for the motor-driven fan-shaped scan. This distance is typically several millimeters. Therefore, the transducer position (x, y) is not fixed but changes depending on the angle at which the operator manually tilts the probe. If ultrasound echo signals are collected under these conditions and an image is generated assuming an ideal fan-shaped scan as shown in Figure 6, the image will be distorted. If the image distortion is not severe, it may be difficult to detect with the naked eye. However, when estimating urine volume from collected ultrasound images, the estimation error can be very large. For example, if the distortion in one direction of the image is 2%, the error in volume calculation can be as large as the cube of the distortion, or 8%. Therefore, when calculating urine volume, the actual trajectory of the ultrasound scan must be taken into account.

[0046] In FIG. 7, when the ultrasound probe is tilted by θ, the amount of movement Δx of the ultrasound probe in the x-axis direction and the amount of movement Δd in the axial direction of the bladder scanner, i.e., the z' direction, are expressed by the following equations.

[0047]

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[0048]

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[0049] In the formula, R represents the radius of the lower end covering of the ultrasound probe, and θ represents the tilt angle of the ultrasound probe due to manual movement.

[0050] Figure 8 shows the actual scanning trajectory when the bladder scanner according to the present invention is manually moved by an operator. The scanning plane taking Δx and Δd into consideration is shown in Figure 8. Here, the ultrasound scanning plane does not converge to a single point O, but changes according to Equations 6 and 7 depending on the tilt angle θ. Because the convergence points of each sector-shaped scanning plane are different, this must be taken into consideration when obtaining a 3D volumetric image. By taking this into consideration, distortion of the ultrasound image can be eliminated, and bladder volume can be measured without error.

[0051] 9 shows the waveform of an ultrasonic echo signal received by an ultrasonic transducer in a bladder scanner according to the present invention. The ultrasonic echo signal received at a scan angle of θ is denoted as S θ The depth r at which the ultrasonic echo signal is generated satisfies Equation 8.

[0052]

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[0053] Here, c is the speed of sound inside the human body, which is approximately 1500 m / s in the soft tissues of the human body. Since there is a linear relationship between time t and depth r, the ultrasonic echo signal is a function of time as well as depth, and is expressed by Equation 9.

[0054]

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[0055] When mechanical scanning is performed as shown in FIG.

[0056] 10 shows coordinates in a mechanical scanning method, and shows scan lines collected at an angle θ. Since the scan lines correspond to polar coordinates on the xy plane, the ultrasound echo signal at a depth r corresponds to the ultrasound image I(x, y) on a rectangular coordinate system using Equation 10.

[0057]

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[0058] By converting the ultrasonic echo signals at all angles using Equation 10, an ultrasonic image in a rectangular coordinate system can be obtained.

[0059] In the case of ultrasonic scanning by manual rotation by the operator, as mentioned above, the scan lines do not converge to a single point but produce displacements of Δd and Δx. FIG. 11 shows the xy coordinate system for ultrasonic scanning by mechanical rotation and the x'y' coordinate system for ultrasonic scanning by manual rotation in the ultrasonic scanner according to the present invention. In ultrasonic scanning by mechanical rotation, the scan lines converge around point O, so the xy plane is fixed at all angles. However, in ultrasonic scanning by manual rotation by the operator, the x'y' plane moves in parallel depending on the angle. (x, y) and (x', y') can be expressed by Equations 11 to 13.

[0060]

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[0061]

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[0062]

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[0063] The ultrasonic echo signal obtained at the θ angle using the ultrasonic scanning method by manual rotation The ultrasonic image signal obtained by subjecting this ultrasonic echo signal to coordinate transformation is expressed by Equation 14.

[0064]

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[0065] Since the (x', y') coordinate system fluctuates depending on the angle, the final ultrasound image signal obtained by converting it into a fixed coordinate system (x, y) is expressed by Equation 15.

[0066]

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[0067] While the present invention has been described above with reference to its preferred embodiments, these are merely illustrative and are not intended to limit the scope of the present invention, and those skilled in the art will recognize that various modifications and applications not exemplified above are possible without departing from the essential characteristics of the present invention. Differences related to these modifications and applications should be construed as being included within the scope of the present invention as defined by the appended claims.

Claims

1. an ultrasonic transducer for transmitting ultrasonic signals to a measurement object and receiving ultrasonic echo signals reflected from the measurement object; a single motor coupled to a central axis of the ultrasonic transducer; an ultrasonic probe in which the ultrasonic transducer and a motor are mounted; a tilt sensor attached to a central axis of the ultrasonic probe and configured to detect a tilt angle of the ultrasonic probe with respect to a second direction; a control unit that acquires fan-shaped two-dimensional ultrasound images at a plurality of tilt angles in response to changes in the tilt angle caused by a manual operation, and acquires the two-dimensional ultrasound images by rotating the ultrasound transducer along a first direction perpendicular to a second direction using the motor; Equipped with The control unit a coordinate correction module; a two-dimensional ultrasound image acquisition module for acquiring a fan-shaped two-dimensional ultrasound image using ultrasound echo signals having the corrected coordinates; The coordinate correction module receiving an ultrasonic echo signal from the ultrasonic transducer; Obtaining initial coordinates (x, y) for the ultrasonic echo signal based on an origin that is preset as a reference position of the ultrasonic transducer; Calculating an error value (Δx, Δy) indicating the degree to which the ultrasonic transducer deviates from the origin using the tilt angle (θ) of the ultrasonic probe provided by the tilt sensor; correcting the initial coordinates for the ultrasonic echo signal using the error value; An ultrasound scanner that provides corrected coordinates (x', y') for ultrasound echo signals.

2. The two-dimensional ultrasound image acquisition module of the control unit includes:

2. The ultrasonic scanner of claim 1, further comprising: driving a motor to rotate the ultrasonic transducer along the first direction, acquiring ultrasonic echo signals according to the rotation, correcting coordinates of the ultrasonic echo signals using the coordinate correction module, and acquiring a fan-shaped two-dimensional ultrasonic image using the ultrasonic echo signals having the corrected coordinates.

3. The corrected coordinates (x', y') of the coordinate correction module are calculated by the following formula: 、 、 、 、 wherein (x, y) indicate initial coordinates for the ultrasonic echo signal based on the origin, (x', y') indicate corrected coordinates for the ultrasonic echo signal taking into account the tilt of the ultrasonic probe, Δd indicates the amount of movement of the ultrasonic probe in the axial direction, and R indicates the radius of the covering at the bottom end of the ultrasonic probe.

4. The control unit 2. The ultrasound scanner according to claim 1, further comprising a three-dimensional information extraction module that acquires a plurality of two-dimensional ultrasound images at a plurality of tilt angles by repeatedly executing the two-dimensional ultrasound image acquisition module in response to a change in tilt angle due to a manual operation, and extracts predetermined three-dimensional information using the plurality of two-dimensional ultrasound images.

5. The three-dimensional information extracted by the control unit is 5. The ultrasound scanner according to claim 4, wherein the urine volume is determined from the volume of the bladder.

Images