Ultrasonic imaging system for accurately collecting heart section under any body position

Abstract

The invention discloses an ultrasonic imaging system for accurately acquiring a heart section under any body position. The ultrasonic imaging system comprises a plurality of two-dimensional ultrasonic arrays, a multi-channel ultrasonic signal acquisition module and a three-dimensional ultrasonic imaging module, wherein the spatial positions of the two-dimensional ultrasonic arrays are randomly distributed; the plurality of two-dimensional ultrasonic arrays, the multi-channel ultrasonic signal acquisition module and the three-dimensional ultrasonic imaging module are connected in sequence; wherein the plurality of two-dimensional ultrasonic arrays comprise: a plurality of ultrasonic transducer arrays form regional line scanning or regional surface scanning or cross surface scanning; according to the invention, more detailed images are provided for doctors, so that the lesion can be more accurately positioned and evaluated; the problems that in wearable ultrasonic heart imaging, correct imaging sections are difficult to collect, and the imaging sections change in movement can be solved. The device is not only suitable for heart, but also suitable for brain, liver, kidney, bladder, aorta abdominalis, inferior vena cava and other human tissues and parts.

Description

Technical Field

[0001] The invention relates to the technical field of ultrasonic imaging, and in particular to an ultrasonic imaging system for accurately acquiring cardiac sections in any body position. Background Art

[0002] With the advancement of medical technology and the increase in demand for disease monitoring, instant heart detection can no longer meet the development of modern medicine. Precision medicine, telemedicine, intensive care, intraoperative navigation, etc. have put forward new requirements for cardiac imaging technology. Continuous, non-invasive, and high-precision monitoring of cardiac activity has become an inevitable trend in the development of medicine. The development of wearable cardiac ultrasound technology and the realization of non-invasive high-resolution visualization monitoring technology of deep tissues are urgent needs for the diagnosis and monitoring of modern heart disease.

[0003] In vitro transthoracic cardiac ultrasound requires acoustic emission and reception from a specific intercostal window, which restricts the applicable detection acoustic window and ultrasonic transducer size of transthoracic ultrasound. At present, transthoracic cardiac ultrasound generally has four commonly used detection windows, including the suprasternal fossa, the left parasternal, the apex, and the subxiphoid process. The commonly used acquisition sections include the parasternal left ventricular long axis section, the parasternal left ventricular short axis section, the apical four-chamber section, the subxiphoid four-chamber section, and the aortic arch long axis section. Existing wearable ultrasound technology faces the problems of limited imaging range and fixed imaging angle. It often cannot acquire complete cardiac images, or cannot accurately acquire the correct cardiac sections with clinical value, thus restricting the actual clinical application of wearable ultrasound technology. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to provide an ultrasonic imaging system for accurately acquiring cardiac sections in any body position, so as to solve the problem of inaccurate imaging sections encountered in current wearable cardiac ultrasonic imaging.

[0005] Technical solution: The ultrasonic imaging system for accurately capturing cardiac cross-sections in any body position described in the present invention comprises a plurality of two-dimensional ultrasonic arrays, a multi-channel ultrasonic signal acquisition module and a three-dimensional ultrasonic imaging module randomly distributed in spatial positions; the plurality of two-dimensional ultrasonic arrays, the multi-channel ultrasonic signal acquisition module and the three-dimensional ultrasonic imaging module are connected in sequence; wherein the plurality of two-dimensional ultrasonic arrays comprise: a plurality of ultrasonic transducer arrays forming a divided area line scan or a divided area surface scan or a cross surface scan.

[0006] Furthermore, the two-dimensional ultrasonic array receives a pulsed high-voltage driving signal and converts it into an ultrasonic signal. After collecting the ultrasonic echo signal, it is converted into an electrical signal again and transmitted to the three-dimensional ultrasonic imaging module; the two-dimensional ultrasonic array is fixed to the target imaging area by medical ultrasonic tape, or fixed by other clamps or mechanical arm structures; the two-dimensional ultrasonic array and human skin tissue are coupled with sound waves by ultrasonic glue or other solid or solid-liquid two-phase materials, and the other end is connected to the multi-channel ultrasonic signal transmission and acquisition module and the host computer through a probe for data transmission.

[0007] Furthermore, the multi-channel ultrasound signal acquisition module is used to acquire signals from the ultrasound array.

[0008] Furthermore, the three-dimensional ultrasonic imaging module is used to obtain a three-dimensional image through a three-dimensional ultrasonic imaging algorithm.

[0009] Furthermore, the two-dimensional ultrasound array is made of piezoelectric ceramics, piezoelectric single crystals or prepared by micro-electromechanical methods, and can be in the form of a thin wearable hard ultrasound patch, a thin wearable flexible ultrasound patch or a handheld ultrasound array.

[0010] Furthermore, the three-dimensional ultrasound imaging algorithm uses an optical three-dimensional camera to capture a three-dimensional image of the chest covered by all ultrasound arrays to obtain the relative spatial positions between the arrays; based on the spatial position of each array, the three-dimensional images of the local parts of the heart collected are combined into a large-scale three-dimensional image using coordinate transformation.

[0011] Furthermore, the position of the ultrasound array in space is determined by binocular vision calibration. The conversion relationship between the pixel coordinate system and the world coordinate system is obtained by coordinate system transformation, and the formula is as follows:

[0012]

[0013] Among them, Zc represents the coordinate of the space point in the Z direction in the camera coordinate system, f x and f y are the equivalent focal lengths of the camera in the x and y directions, respectively, x and c y Represents the pixel coordinates of the center of the image. (u,v) and (X w ,Y w ,Z w ) represent the coordinates in the pixel coordinate system and the world coordinate system respectively.

[0014] Furthermore, the three-dimensional ultrasonic imaging module adopts ultrasonic B-mode imaging or Doppler mode.

[0015] Furthermore, after acquiring a large-scale three-dimensional cardiac image, a specific section is intercepted from the large-scale three-dimensional cardiac image to obtain an accurately acquired cardiac section in any body position.

[0016] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: it can obtain local three-dimensional images of the heart from multiple angles, and can collect more heart information than traditional ultrasonic imaging technology. It can be combined into a large-scale three-dimensional image of the heart using a three-dimensional image registration method, providing doctors with more detailed images, which helps to more accurately locate and evaluate lesions; it can solve the problems of difficulty in collecting correct imaging sections and changes in imaging sections during movement in wearable ultrasonic cardiac imaging; it is not only applicable to the heart, but also to human tissues and parts such as the brain, liver, kidneys, bladder, abdominal aorta, and inferior vena cava. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is the overall architecture diagram of the present invention;

[0018] Figure 2 It is a schematic diagram of fixing the ultrasound array;

[0019] Figure 3 A schematic diagram of a process for positioning an ultrasound array using an optical three-dimensional camera and registering multiple ultrasound images;

[0020] Figure 4 Schematic diagram of binocular vision calibration method;

[0021] Figure 5 It is a schematic diagram of the conversion between the ultrasound array coordinate system and the world coordinate system;

[0022] Figure 6 It is a schematic diagram of the acoustic field scanning method of a multi-ultrasound array;

[0023] Figure 7 Schematic diagram of ultrasound array beamforming.

[0024] Among them, 1. Ultrasonic array; 2. Signal line; 3. 3D optical camera; 4. Ultrasonic array; 5. Ultrasonic glue or non-volatile liquid; 6. Thin film medical tape; 7. Coupling media such as water bag or hydrogel; 8. Skin; 9. Ultrasonic array. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0026] like Figure 1-Figure 7As shown, an embodiment of the present invention provides an ultrasound imaging system for accurately capturing cardiac sections in any body position. According to the position of the heart, multiple ultrasound arrays 1 are generally selected at the positions of the 2nd to 5th intercostal spaces to be fixed. Multiple two-dimensional ultrasound arrays 1 are connected to a multi-channel ultrasound signal acquisition module via a data line 2 to obtain an ultrasound image of each ultrasound array. The ultrasound image is transmitted to a three-dimensional ultrasound imaging module to align the three-dimensional ultrasound images of multiple perspectives to obtain a large-scale three-dimensional image of the heart, and finally the desired section can be accurately obtained therefrom.

[0027] Apply an appropriate amount of ultrasound glue or other non-volatile liquid on the sound wave emitting surface of the ultrasound array and the skin surface, use a water bag or hydrogel as the acoustic coupling medium, press the water bag or hydrogel block between the ultrasound array and the skin, and then fix the ultrasound array with airtight medical tape. Figure 2 The corresponding schematic diagram of ultrasound array fixation is shown.

[0028] The chest area is photographed using a binocular three-dimensional optical imaging method, and all ultrasound arrays are covered to obtain the high-precision relative spatial position of the ultrasound array and the orientation angle in three-dimensional space. Subsequently, simple and fast preliminary image alignment can be achieved through coordinate transformation. Figure 3 Show the corresponding process.

[0029] The position of the ultrasound array in space can be determined by binocular vision calibration. Figure 4 As shown in the figure, through the coordinate system transformation, the conversion relationship between the pixel coordinate system and the world coordinate system can be obtained as follows:

[0030]

[0031] Zc represents the coordinate of the space point in the Z direction in the camera coordinate system, f x and f y are the equivalent focal lengths of the camera in the x and y directions, respectively, x and c y Represents the pixel coordinates of the center of the image. (u,v) and (X w ,Y w ,Z w ) represent the coordinates in the pixel coordinate system and the world coordinate system respectively.

[0032] In the above formula,

[0033]

[0034] The intrinsic parameter matrix M1 depends on the camera specifications and is generally a known or calibrable parameter. The extrinsic parameter matrix M2 is determined based on the rotation matrix R and the translation matrix T between the world coordinate system and the camera coordinate system. Specifically, if the camera coordinate system rotates around the world coordinate system X w Axis, Y wAxis and Z w The angles of the axes are α, β, γ, and the offset is T x ,T y ,T z , then R and T can be expressed as

[0035]

[0036] In the case of binocular positioning, there are two sets of pixel coordinate systems PCS1 and PCS2. Through the least squares method, the accurate coordinates (X w ,Y w ,Z w )for

[0037]

[0038] H and U represent two sets of parameter matrices and augmented pixel coordinates, respectively.

[0039] When two sets of pixel coordinates are known, the specific position of the ultrasound array can be obtained. The ultrasound array coordinate system can be determined in the following way. First, determine the center position of the super array according to the above formula, and construct the ultrasound array coordinate system with the long axis of the array as the x-axis, the short axis as the y-axis, and the axis perpendicular to the plane of the array as the z-axis. In the world coordinate system, the vectors corresponding to the x and y axes can be determined by taking any two points, and the vector corresponding to the z axis can be determined by the outer product of the above two vectors.

[0040] like Figure 5 As shown, when the relative spatial position of the ultrasound array and the orientation angle in three-dimensional space are known, the conversion relationship between the two sets of coordinates can be obtained:

[0041]

[0042] The rotation matrix and translation matrix R Xx and T Xx The solution of is similar to that of the external parameter matrix M2. Xx Indicates the coordinates of the array center in the world coordinate system.

[0043] like Figure 6As shown, the two-dimensional ultrasonic array includes regional line scanning, regional surface scanning, and cross-surface scanning. The first method is to divide the entire scanning area into several lines, and each line is scanned in turn, which is suitable for the spatial arrangement of multiple arrays parallel or perpendicular to each other; the second method is to divide the entire scanning area into several sub-areas, and each sub-area is scanned block by block, which is suitable for the arrangement of multiple arrays parallel to each other. The plane wave composite imaging method can obtain a higher frame rate, but there are certain requirements for the array arrangement; the third method is to divide the scanning area into several cross-surfaces, each of which has a certain overlap, and obtain complete three-dimensional data through multiple scans. It is suitable for the situation where multiple arrays have to be arranged cross-wise, but due to the inevitable overlap of sound fields, it may face strong sound field mutual interference.

[0044] The multi-channel ultrasound signal acquisition module collects ultrasound signals from each array and reconstructs a three-dimensional heart image through beamforming. Figure 7 As shown, the three-dimensional area below the two-dimensional ultrasonic array is scanned and imaged using a spatial composite plane wave acoustic field method. The plane wave forms an angle θ with the y-axis. The ultrasonic signal collected by the nth unit of the array is p n (t), its spatial position is (x n ,y n ), then the acoustic emission transmission time between the spatial position (x, y, z) in the imaging area and the nth array element is

[0045] t em =(z·cosθ+y·sinθ) / c,

[0046] The sound reflection transmission time is

[0047]

[0048] Therefore, the total time delay between transmission and reception is

[0049]

[0050] c is the speed of sound in the tissue. By superimposing the acoustic signals transmitted and received by N piezoelectric units and plane waves at M angles, the pixel value at the (x, y, z) position can be determined as:

[0051]

[0052] According to the above algorithm, the local three-dimensional ultrasound image of the heart corresponding to each ultrasound array is obtained, and then the coordinate conversion formula is used

[0053]

[0054] The pixel value at the position (Xw, Yw, Zw) can be obtained

[0055] p(X w , Y w , Z w )=p(R Xx -1 x+T Xx )

[0056] θ1, θ2, θ3 represent the x-axis and X-axis, respectively. w axis, y-axis and Y w axis and z-axis with Z w The angle between the axes, T X , T Y , T Z Indicates the position of the array center in the world coordinate system.

[0057] The real-time three-dimensional ultrasound image of the human body can be regarded as the superposition of images obtained by multiple adjusted ultrasound arrays. Under K ultrasound arrays, the real-time three-dimensional image can be expressed as

[0058]

[0059] Cut out specific cardiac slices from a large range of cardiac 3D images to accurately obtain the required cardiac slice. Determine the required cardiac slice position, and the slice can be expressed by a plane equation

[0060] AX w +BY w +CZ w +D=0

[0061] A, B, and C are the components of the plane normal vector, and D is the distance between the plane and the origin.

[0062] Determine the plane normal vector n = [A, B, C] and a known point P0 = [x0, y0, z0] on the tangent plane, and substitute them into the above formula to calculate D

[0063]

[0064] Traverse all the pixels of the 3D image and determine whether each pixel is on the plane according to the plane equation:

[0065] |AX wi +BY wi +CZ wi +D|<ε

[0066] The pixel values ​​of the points that meet the above conditions are extracted to generate a two-dimensional cross-sectional image.

[0067] The present invention fixes multiple ultrasonic arrays in the 2nd to 5th intercostal spaces, and ensures stable contact between the array and the skin through acoustic coupling media and medical tape. A binocular three-dimensional optical imaging method is used to obtain the relative spatial position and three-dimensional spatial orientation angle of the ultrasonic array, and preliminary image registration is achieved through coordinate transformation to obtain the conversion relationship between the pixel coordinate system and the world coordinate system. A high-voltage pulse is applied to the ultrasonic array by circuit control, and the sound beam shape and direction of multiple ultrasonic arrays are precisely controlled by precisely controlling the excitation delay of the piezoelectric unit, and performing regional line scanning, regional surface scanning and cross-surface scanning. A three-dimensional heart image is reconstructed through a beamforming method, and finally a specific section is intercepted from a large-scale 3D heart image using a spatial geometry algorithm to generate a two-dimensional section image, thereby achieving precise acquisition of a specific section of the heart.

Claims

1. An ultrasonic imaging system for accurately acquiring cardiac sections in any body position, characterized in that: It includes multiple two-dimensional ultrasonic arrays, multi-channel ultrasonic signal acquisition modules and three-dimensional ultrasonic imaging modules randomly distributed in spatial positions; the multiple two-dimensional ultrasonic arrays, multi-channel ultrasonic signal acquisition modules and three-dimensional ultrasonic imaging modules are connected in sequence; wherein the multiple two-dimensional ultrasonic arrays include: multiple ultrasonic transducer arrays form regional line scanning or regional surface scanning or cross-surface scanning.

2. The ultrasonic imaging system for accurately acquiring cardiac sections in any body position according to claim 1, characterized in that: The two-dimensional ultrasonic array receives a pulsed high-voltage driving signal and converts it into an ultrasonic signal. After collecting the ultrasonic echo signal, it is converted into an electrical signal again and transmitted to the three-dimensional ultrasonic imaging module. The two-dimensional ultrasonic array is fixed to the target imaging area by medical ultrasonic tape, or fixed by other clamps or mechanical arm structures. One end of the two-dimensional ultrasonic array is coupled to the human skin tissue by ultrasonic glue or other solid or solid-liquid two-phase materials, and the other end is connected to the multi-channel ultrasonic signal transmission and acquisition module and the host computer for data transmission.

3. The ultrasonic imaging system for accurately acquiring cardiac sections in any body position according to claim 1, characterized in that: The multi-channel ultrasonic signal acquisition module is used to acquire signals from the ultrasonic array.

4. The ultrasonic imaging system for accurately acquiring cardiac sections in any body position according to claim 1, characterized in that: The three-dimensional ultrasonic imaging module is used to obtain a three-dimensional image through a three-dimensional ultrasonic imaging algorithm.

5. The ultrasonic imaging system for accurately acquiring cardiac sections in any body position according to claim 1, characterized in that: The two-dimensional ultrasound array is made of piezoelectric ceramics, piezoelectric single crystals or prepared by micro-electromechanical methods, and is in the form of a thin wearable hard ultrasound patch, a thin wearable flexible ultrasound patch or a handheld ultrasound array.

6. The ultrasonic imaging system for accurately acquiring cardiac sections in any body position according to claim 1, characterized in that: The three-dimensional ultrasound imaging algorithm uses an optical three-dimensional camera to capture a three-dimensional image of the chest covered by all ultrasound arrays to obtain the relative spatial positions between the arrays; based on the spatial position of each array, the three-dimensional images of the local parts of the heart are combined into a large-scale three-dimensional image using coordinate transformation.

7. The ultrasonic imaging system for accurately acquiring cardiac sections in any body position according to claim 6, characterized in that: The position of the ultrasound array in space is determined by binocular vision calibration. The conversion relationship between the pixel coordinate system and the world coordinate system is obtained by coordinate system transformation. The formula is as follows: Among them, Zc represents the coordinate of the space point in the Z direction in the camera coordinate system, f x and f y are the equivalent focal lengths of the camera in the x and y directions, respectively, x and c y Represents the pixel coordinates of the center of the image. (u,v) and (X w ,Y w ,Z w ) represent the coordinates in the pixel coordinate system and the world coordinate system respectively.

8. The ultrasonic imaging system for accurately acquiring cardiac sections in any body position according to claim 1, characterized in that: The three-dimensional ultrasound imaging module adopts ultrasound B-mode imaging or Doppler mode.

9. The ultrasonic imaging system for accurately acquiring cardiac sections in any body position according to claim 1, characterized in that: After acquiring a large-scale three-dimensional cardiac image, a specific section is intercepted from the large-scale three-dimensional cardiac image to obtain an accurately acquired cardiac section in any body position.

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