A dual-plane ultrasonic transducer probe and a method for setting the transducer position thereof

Abstract

The present invention relates to a transducer probe of a dual-plane puncture ultrasound guidance system and a method for setting the transducer position thereof. A dual-plane probe having two transducers is constructed by transforming the position of a single-plane transducer in a three-dimensional coordinate system, wherein the position transformation includes a horizontal movement transformation and an angle transformation in three directions, so that the angle between the two transducers of the probe is adjustable, and the two angles with the horizontal plane are adjustable. The optimal dual-plane puncture probe can be designed according to the puncture requirements of the body part. The scanning planes of the two transducers intersect on the needle insertion path, so that the needle insertion process of the puncture needle can be displayed from different dimensions, and the deviation of the puncture needle in the passive aperture direction of each transducer can be corrected in real time, and all angle relationships are mutually converted through mathematical expressions, and according to different application scenarios, the design of the dual-plane transducer probe is guided, and the transducer parameters can be quickly and automatically accurately set to match the specific puncture target, thereby improving the accuracy of puncture guidance.

Description

Technical Field

[0001] The present invention relates to the technical field of ultrasonic transducers, and in particular to a dual-plane ultrasonic transducer probe and a method for setting the position of the transducer therein. Background Art

[0002] In order to solve the problem of accurate positioning of the needle or needle tip during puncture guidance, researchers at home and abroad have proposed a dual-plane ultrasonic transducer. The two ultrasonic transducers of a traditional dual-plane ultrasonic transducer are arranged in a T-shape or L-shape. Whether it is a T-shape or L-shape dual-plane ultrasonic transducer, their two linear array transducers maintain a completely vertical relative position relationship, so the two imaging planes of the T-shape or L-shape dual-plane ultrasonic transducer remain vertical. Figure 1 The imaging plane of the T-type dual-plane ultrasound probe is shown. The imaging plane of transducer 1 corresponds to the in-plane view. The outline of the puncture instrument can be fully displayed in this imaging plane, but the relative position relationship between the puncture instrument and the surrounding tissue in the cross section cannot be displayed. The imaging plane of transducer 2 corresponds to the out-of-plane view, which is orthogonal to the in-plane view, so the relative position relationship between the puncture instrument and the surrounding tissue in the cross section can be displayed in this imaging plane. When a T-type or L-type dual-plane ultrasound transducer is used for puncture guidance, the puncture needle first appears in the imaging plane corresponding to transducer 1. The puncture needle may not be observed in the imaging plane due to the partial volume effect or the needle tip of the puncture needle runs out of the sound beam scanning range of transducer 1. The sound field of the ultrasonic transducer in the passive aperture direction is not a strict "slice" but a slice with a certain thickness. Therefore, the image displayed on the ultrasound imaging plane is a superposition of information perpendicular to the imaging plane direction and within a certain range, which is called the partial volume effect in the field of medical ultrasound. When the puncture needle continues to be inserted until it appears in the corresponding imaging plane of the transducer 2, the positional relationship between the puncture needle and the surrounding tissue can be determined. At this time, if the puncture needle deviates, it must be re-punctured. This process increases the puncture time and puncture failure rate and may cause damage to the surrounding tissue. Therefore, the traditional T-type or L-type dual-plane ultrasonic transducer does not have the ability to correct the puncture needle insertion path in real time.

[0003] In the prior art, dual-plane ultrasonic imaging can be achieved by using a full-surface array transducer. Although the effect is good, the array of tens of thousands of channels and the imaging cost limit its widespread popularization.

[0004] There are other ways of improvement in the prior art. For example, utility model patent 202122239361.X discloses a dual-plane ultrasonic transducer probe device, which can see the puncture needle at the same time in each plane to guide the puncture by changing the angle between the two transducers and the angle between the transducer and the base. However, it can only change the angle between the two transducers and the angle between the transducer and the base, and cannot accurately change the angle according to the puncture requirements, which will cause some targets to be unable to puncture; and the angle between the two transducers and the angle between the transducer and the base depend on experience. When using it, the doctor needs to stick the probe to the inspected part to try and adjust it manually, which makes it very inconvenient to use; at the same time, the angle between the two transducers and the angle between the transducer and the base are adjusted independently, and there is no correlation between the two. It also makes it difficult for doctors to find a probe setting that matches their specific puncture target in actual use, which reduces the accuracy of puncture guidance and increases the possibility of puncture failure.

[0005] In order to solve the above problems, the present invention proposes a novel method for constructing a dual-plane ultrasonic transducer probe, by transforming the position of a single-plane transducer in a three-dimensional coordinate system to construct a dual-plane probe with two transducers, wherein the position transformation includes a horizontal movement transformation and an angle transformation in three directions, so that the angle between the two transducers of the probe is adjustable, and the two angles with the horizontal plane are adjustable. The optimal dual-plane puncture probe can be designed according to the puncture requirements of the body part. The scanning planes of the two transducers intersect on the needle insertion path, so that the needle insertion process of the puncture needle can be displayed from different dimensions, and the deviation of the puncture needle in the passive aperture direction of each transducer can be corrected in real time, and all angle relationships are converted to each other through mathematical expressions, and according to different application scenarios, the design of the dual-plane transducer probe is guided, and the transducer parameters can be quickly and automatically set accurately to match the specific puncture target, thereby improving the accuracy of puncture guidance. Summary of the invention

[0006] The present invention proposes a dual-plane ultrasonic transducer probe and a method for setting the position of the transducer therein. By transforming the position of a single-plane transducer in a three-dimensional coordinate system, a dual-plane ultrasonic transducer probe with two transducers is constructed. The scanning planes of the two transducers intersect on the needle insertion path, so that the needle insertion process of the puncture needle can be displayed from different dimensions and the deviation of the puncture needle in the passive aperture direction of each transducer can be corrected in real time.

[0007] A method for setting the position of a transducer in a dual-plane ultrasonic transducer probe is based on a single-plane ultrasonic transducer facing human tissue and attached to the skin, and the position of the single-plane ultrasonic transducer in a three-dimensional coordinate system is transformed to calculate the positions of two transducers in the dual-plane ultrasonic transducer probe, characterized in that the method comprises the following steps:

[0008] s1: Place the single-plane ultrasonic transducer at a position facing the human tissue and fitting the skin, and establish a plane rectangular coordinate system with the skin surface as the xoy plane, so that one vertex of the single-plane ultrasonic transducer is located at the origin, its long axis is located in the positive direction of the x-axis, and its short axis is located in the negative direction of the y-axis, where the long axis of the ultrasonic transducer is its long side, that is, the active aperture direction, and the short axis is the wide side of the ultrasonic transducer, that is, the passive aperture direction. The position of the single-plane ultrasonic transducer is the initial position (x, y, z);

[0009] s2: The ultrasonic transducer at the initial position is translated by δ along the negative direction of the y-axis. The coordinates of the ultrasonic transducer after translation are (x, y-δ, z) T ;

[0010] s3: Rotate the ultrasonic transducer clockwise around the short axis by α degrees. At this time, the short axis coincides with the y-axis. The transducer coordinates corresponding to this change are equal to the right-hand multiplication of the transducer coordinates after translation by the rotation matrix R around the y-axis. y , R y The expression is:

[0011]

[0012] s4: Rotate the transducer β degrees around the long axis. This rotation can be decomposed into the following process: first rotate the transducer around the y-axis so that one of its long sides coincides with the x-axis, then rotate the transducer β degrees clockwise around the x-axis, and finally obtain the coordinates of the transducer P1 by the inverse transformation of the rotation around the y-axis. The total transformation matrix H of this series of transformations is as follows:

[0013]

[0014]

[0015]

[0016] in YesR y1 The inverse matrix of

[0017] s5: Mirror the position of ultrasonic transducer P1 to obtain the geometric position of transducer P2. The mirror plane is perpendicular to the xoy plane and the angle between it and the projection of the long axis of P1 on the xoy plane (i.e., the angle with the x-axis) is At this time, the unit normal vector of the mirror plane is The unit normal vector of the mirror plane is The corresponding mirror matrix is

[0018]

[0019] Right now

[0020]

[0021] The coordinates of transducer P1 are right-multiplied by Q to obtain the coordinates of transducer P2;

[0022] S6: Use ultrasonic transducers P1 and P2 as two transducer components of a dual-plane ultrasonic transducer probe.

[0023] Preferably, the ultrasonic transducers P1 and P2 can be linear transducers, convex array transducers, or phased array transducers, respectively.

[0024] Preferably, the parameters δ, α, β, and γ of the dual-plane ultrasonic transducer are adjusted according to the blind area depth and the needle insertion angle.

[0025] Preferably, the parameter range of the dual-plane ultrasonic transducer is δ≥4 mm, α≤10°, β≤20°, and γ is around 90°.

[0026] Preferably, when the biplane ultrasonic transducer is used for kidney puncture biopsy, its parameters are set to δ=4 mm, α=10°, β=20° and γ=90°.

[0027] The present invention also proposes a dual-plane ultrasonic transducer probe, comprising two ultrasonic transducers, wherein the positions of the two ultrasonic transducers are set using the method for setting the transducer positions in the dual-plane ultrasonic transducer probe as described above, and the intersection of the scanning planes of the two transducers is the guide line of the needle insertion path. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] These and / or other aspects of the present invention will become apparent and more easily understood from the following description of embodiments in conjunction with the accompanying drawings, in which:

[0029] Figure 1 Figure 1 shows the imaging planes of a T-shaped biplane ultrasound probe.

[0030] Figure 2 It is the geometric relationship between the L / T type dual-plane ultrasonic transducer and the new dual-plane ultrasonic transducer.

[0031] Figure 3 It is a new type of dual-plane ultrasonic transducer geometry.

[0032] Figure 4 It is the construction process of a dual-plane ultrasonic transducer.

[0033] Figure 5 It is a schematic diagram of the blind spot depth and needle insertion angle of the puncture path under ultrasound puncture guidance.

[0034] Figure 6 It is the influence of the structural parameters of the biplane ultrasonic transducer on the needle insertion path. DETAILED DESCRIPTION

[0035] Figure 2 The geometric relationship between the traditional L-type or T-type biplane ultrasonic transducer and the new biplane ultrasonic transducer is shown. The main transducer and the auxiliary transducer of the L / T probe together form the L / T biplane ultrasonic transducer, while the main transducer and the auxiliary transducer of the improved probe together form the new biplane ultrasonic transducer. The green line in the figure represents the needle insertion path. The L / T biplane ultrasonic transducer and the new biplane ultrasonic transducer assist in guiding the puncture needle on this needle insertion path. The purple ball represents the puncture target, and the blue arrows on both sides represent the relative offset between the puncture needle and the puncture target. For the L / T biplane ultrasonic transducer, the scanning plane corresponding to the main transducer can observe the entire needle insertion process of the puncture needle, but the auxiliary transducer of the L / T probe can only display a point where the needle insertion path intersects with its scanning plane, and corrects the deviation between the puncture needle and the puncture target in the passive aperture direction of the main transducer according to the position of this point in the ultrasonic imaging of the auxiliary transducer. This imaging method of the L / T type dual-plane ultrasound transducer does not fully utilize the auxiliary transducer to bring more information about the position of the puncture needle in different dimensions. Based on this understanding, a new design idea of ​​a dual-plane probe is proposed. The auxiliary transducer of the L / T type probe in the figure changes its position to the auxiliary transducer of the improved probe after geometric transformation, and it intersects with the scanning plane corresponding to the main transducer on the needle insertion path. At this time, the auxiliary transducer can also observe the puncture needle during the entire needle insertion process like the main transducer. The auxiliary transducer and the main transducer display the puncture needle insertion process from different dimensions, and can correct the deviation of the puncture needle in the passive aperture direction of each transducer in real time.

[0036] because Figure 2 The auxiliary transducer of the new ultrasonic probe shown in the figure has already invaded the human tissue when the main transducer is facing the human tissue and close to the skin, which is physically impossible. Therefore, based on the design idea of ​​the dual-plane ultrasonic transducer proposed above, the dual-plane ultrasonic transducer is rotated as a whole to obtain Figure 3 The new dual-plane ultrasonic transducer shown in FIG. It consists of two mirror-symmetrical transducers, and the intersection of the scanning planes of the two transducers is used as the needle insertion path.

[0037] Figure 3The design method of obtaining a novel dual-plane ultrasound probe geometric structure from a single transducer is demonstrated: based on a single-plane transducer facing human tissue and fitting the skin, the transducer is translated and rotated in pitch and roll degrees of freedom to obtain transducer 1, and then transducer 1 is mirror-symmetric about a mirror plane to obtain the position of transducer 2, and the mirror plane is at a certain yaw angle with transducer 1. Through the above geometric transformation operations, the geometric configuration of the two transducers of the dual-plane transducer can be obtained.

[0038] The specific construction process of the dual-plane ultrasonic transducer will be given below. For the convenience of discussion, the parameters used in the geometric transformation of the ultrasonic transducer are first defined. The long axis is defined as the long side of the ultrasonic transducer, that is, the active aperture direction, and the short axis is defined as the wide side of the ultrasonic transducer, that is, the passive aperture direction, where the long axis and short axis of the transducer are denoted as a and b respectively. A plane rectangular coordinate system is established with the skin surface as the xoy plane, and the coordinates of any position of the transducer are marked as (x, y, z) T Transducer 1 of the biplanar ultrasonic transducer is denoted as P1 and transducer 2 is denoted as P2. Figure 4 In the described geometric transformation, the rectangle surrounded by black lines represents the initial state of the ultrasonic transducer plane, one of its vertices is located at the origin, the major axis is located in the positive direction of the x-axis, and the minor axis is located in the negative direction of the y-axis. In each step of the geometric transformation, the transducer translates a distance δ along the negative direction of the y-axis in step 1, the pitch angle of rotation around the minor axis in step 2 is α, and the roll angle of rotation around the major axis in step 3 is β. The ultrasonic transducer in the initial state obtains the position of transducer P1 by steps 1 to 3 of the geometric transformation. In step 4, the position of transducer P2 is obtained after the P1 transducer is mirrored about the mirror plane, where the mirror plane is perpendicular to the xoy plane and has a yaw angle with the transducer. The yaw angle is defined as the angle between the mirror plane and the projection of the transducer's long axis onto the xoy plane.

[0039] In order to facilitate mathematical analysis, the geometric transformation matrix is ​​used to quantitatively describe the geometric transformation process from a single-plane transducer to a new dual-plane ultrasonic transducer, as follows:

[0040] 1) First, the transducer at the initial position is translated by δ along the negative direction of the y-axis. At this time, the coordinates of the transducer at any position after translation are (x, y-δ, z) T .

[0041] 2) The transducer rotates α degrees clockwise around the minor axis. At this time, the minor axis coincides with the y-axis, so the transducer coordinates corresponding to this change are equal to the transducer coordinates after translation multiplied by the rotation matrix R around the y-axis. y , R y The expression is:

[0042]

[0043] 3) After rotating around the short axis, the transducer then rotates β degrees around the long axis. This rotation can be decomposed into the following process: first rotate the transducer around the y-axis so that one of its long sides coincides with the x-axis, then rotate the transducer clockwise around the x-axis by β degrees, and finally obtain the transducer P1 by the inverse transformation of restoring the rotation around the y-axis. The total transformation matrix H of this series of transformations is as follows:

[0044]

[0045]

[0046]

[0047] in YesR y1 The inverse matrix of .

[0048] 4) Transducer P1 is mirrored to obtain the geometric position of transducer P2. The mirror plane is perpendicular to the xoy plane and the angle between it and the projection of the long axis of P1 on the xoy plane (i.e., the angle with the x-axis) is At this time, the unit normal vector of the mirror plane is The unit normal vector of the mirror plane is The corresponding mirror matrix is

[0049]

[0050] Right now

[0051]

[0052] The coordinates of transducer P1 are multiplied by Q to obtain the coordinates of transducer P2. The two transducers will be Figure 3 Place it according to the geometric relationship.

[0053] By combining the transformation steps in the form of matrix multiplication, we can obtain the transformation matrix from the initial state of the single-plane transducer to the P1 transducer and P2 after translation, which is called the construction matrix R P1 and R P2 , the expressions of the two matrices are:

[0054]

[0055] R P2 =QR P1

[0056] It can be seen that when two single-plane ultrasonic transducers are given, the dual-plane ultrasonic transducer is determined by the parameters δ, α, β, and γ.

[0057] In addition to solving the problem of precise positioning of the puncture needle under ultrasound guidance, it is also necessary to consider the additional design requirements of the practicality of the biplane ultrasonic transducer. Different application scenarios require different transducer geometries, such as linear transducers for superficial applications and convex array transducers for the abdomen. In order to simplify the problem and evaluate the effectiveness of the project, the biplane ultrasonic transducer will be designed with renal puncture biopsy as the application scenario, so the biplane ultrasonic transducer should meet the requirements of renal puncture biopsy. The following summarizes the design requirements of the biplane ultrasonic transducer, and the subsequent biplane ultrasonic transducer will be developed around these requirements.

[0058] 1) The transducer should fit the skin surface as closely as possible.

[0059] 2) The blind area depth of needle insertion should be less than the target depth.

[0060] 3) The size of the transducer must meet the placement requirements of the puncture part.

[0061] 4) Try to reduce the length of the needle insertion path to reduce the harm of puncture to the human body.

[0062] 5) Biplane ultrasound transducer is suitable for renal puncture biopsy.

[0063] 6) The planned puncture path should ensure that the puncture target is close to the middle of the transducer imaging area.

[0064] Figure 5 The geometric relationship between the puncture needle, the target and the human skin and some important geometric parameters during the ultrasonic puncture process are shown. In the design process of the ultrasonic probe, the main issues that need to be considered are. During the puncture process, due to the scanning angle limitation of the ultrasonic transducer and the distance between the puncture needle and the transducer, the puncture instrument will not be covered by the ultrasonic energy and displayed in the imaging until the needle has entered a certain distance. This area that cannot be monitored by ultrasonic imaging is the blind spot on the needle insertion path, and the depth of the blind spot should be significantly smaller than the target depth. The needle insertion angle refers to the angle between the needle insertion path of the puncture instrument and the skin surface. When the puncture target depth is fixed, the larger the needle insertion angle, the smaller the length the puncture needle needs to travel in the human tissue. On the other hand, for puncture targets with a fixed depth, if the needle insertion angle is too large, the target will deviate excessively from the center of the transducer scanning plane, which is not conducive to the display of the puncture target by the ultrasonic probe.

[0065] In biplane ultrasound imaging, the intersection of the two scanning planes passing through the center of the short axis is used as the insertion path of the puncture needle. The insertion path of the biplane ultrasound transducer can be calculated based on the construction principle and geometric parameters of the biplane ultrasound transducer, and then the blind area depth and the insertion angle of the insertion path can be obtained. In order to facilitate the analysis of the influence of the construction parameters δ, α, β, and γ of the biplane ultrasound transducer on the insertion path, the control variable method is used to analyze the insertion path of the biplane ultrasound transducer. When considering the influence of one of the parameters on the insertion path, the other parameters remain unchanged. The parameter settings when the parameters remain unchanged are shown in the table below.

[0066] Table 1 Geometric parameters of biplane ultrasonic transducer

[0067]

[0068] Figure 6 The changes of blind area depth and needle angle of the needle insertion path when the parameters δ, α, β, and γ change are described respectively. As can be seen from the figure, the α parameter has little effect on the needle insertion path. At the same time, since α is the pitch angle of the transducer rotating around the short axis, it cannot make a large angle, so the adjustment range of the α parameter is limited. The β parameter mainly affects the needle insertion angle. A smaller β parameter can achieve a large needle insertion angle, but a too large β parameter will lead to a too large needle insertion angle, which is not conducive to the display of the puncture target in the center of the scanning plane. A too small γ parameter will lead to a too large blind area depth, and a too large γ parameter will also lead to a too large needle insertion angle. For fit considerations, the two transducers on the dual-plane probe need to be staggered at a certain distance, and the corresponding δ parameter cannot be too small. On the other hand, while ensuring fit, continuing to increase the δ parameter will lead to an unnecessary increase in the blind area depth. At the same time, in the fit test of the dual-plane ultrasound probe, it was found that when δ≥4mm, α≤10°, β≤20°, and γ was near 90°, the probe could maintain good tissue fit.

[0069] In order to simplify the problem and evaluate the effectiveness of the project, the biplane ultrasonic transducer will be designed with renal puncture biopsy as the application scenario. The depth of the lesion in renal puncture is generally between 30mm and 100mm. In order to reduce the length of the puncture path as much as possible and make the blind area depth much smaller than the lesion depth of renal puncture, based on the above parameter analysis, it is determined that the δ of the biplane ultrasonic transducer is equal to 4mm, α is equal to 10°, β is equal to 20° and γ is equal to 90°. At this time, the blind area depth of the biplane ultrasonic transducer is 9mm, and the needle insertion angle is 64.5°, where the blind area depth is much smaller than the lesion depth of renal puncture.

[0070] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for setting the position of a transducer in a dual-plane ultrasonic transducer probe, based on a single-plane ultrasonic transducer facing human tissue and attached to the skin, transforming the position of the single-plane ultrasonic transducer in a three-dimensional coordinate system to calculate the positions of two transducers in the dual-plane ultrasonic transducer probe, characterized in that The following steps are involved: s1: Place the single-plane ultrasonic transducer at a position facing the human tissue and fitting the skin, and establish a plane rectangular coordinate system with the skin surface as the xoy plane, so that one vertex of the single-plane ultrasonic transducer is located at the origin, its long axis is located in the positive direction of the x-axis, and its short axis is located in the negative direction of the y-axis, where the long axis of the ultrasonic transducer is its long side, that is, the active aperture direction, and the short axis is the wide side of the ultrasonic transducer, that is, the passive aperture direction. The position of the single-plane ultrasonic transducer is the initial position (x, y, z); s2: The ultrasonic transducer at the initial position is translated by δ along the negative direction of the y-axis. The coordinates of the ultrasonic transducer after translation are (x, y-δ, z) T ; s3: Rotate the ultrasonic transducer clockwise around the short axis by α degrees. At this time, the short axis coincides with the y-axis. The transducer coordinates corresponding to this change are equal to the right-hand multiplication of the transducer coordinates after translation by the rotation matrix R around the y-axis. y , R y The expression is: s4: Rotate the transducer β degrees around the long axis. This rotation can be decomposed into the following process: first rotate the transducer around the y-axis so that one of its long sides coincides with the x-axis, then rotate the transducer β degrees clockwise around the x-axis, and finally obtain the coordinates of the transducer P1 by the inverse transformation of the rotation around the y-axis. The total transformation matrix H of this series of transformations is as follows: in, in YesR y1 The inverse matrix of s5: Mirror the position of ultrasonic transducer P1 to obtain the geometric position of transducer P2. The mirror plane is perpendicular to the xoy plane and the angle between it and the projection of the long axis of P1 on the xoy plane, that is, the angle with the x-axis, is At this time, the unit normal vector of the mirror plane is The unit normal vector of the mirror plane is The corresponding mirror matrix is Right now The coordinates of transducer P1 are right-multiplied by Q to obtain the coordinates of transducer P2; S6: Use ultrasonic transducers P1 and P2 as two transducer components of a dual-plane ultrasonic transducer probe.

2. The method for setting the transducer position in a dual-plane ultrasonic transducer probe as described in claim 1, wherein the ultrasonic transducers P1 and P2 are linear transducers or convex array transducers or phased array transducers.

3. The method for setting the transducer position in a dual-plane ultrasonic transducer probe as described in claim 1, wherein the parameters δ, α, β, and γ of the dual-plane ultrasonic transducer are adjusted according to the blind area depth and the needle insertion angle.

4. The method for setting the transducer position in a dual-plane ultrasonic transducer probe as described in claim 3, wherein the parameter range of the dual-plane ultrasonic transducer is δ≥4mm, α≤10°, β≤20°, and γ=90°.

5. The method for setting the transducer position in a dual-plane ultrasonic transducer probe as described in claim 3, wherein when the dual-plane ultrasonic transducer is used for renal puncture biopsy, its parameters are set to δ=4mm, α=10°, β=20° and γ=90°.

6. A dual-plane ultrasonic transducer probe, comprising two ultrasonic transducers, wherein the positions of the two ultrasonic transducers are set using the method for setting the transducer positions in a dual-plane ultrasonic transducer probe as described in any one of claims 1 to 5, and the intersection of the scanning planes of the two transducers is the guide line of the needle insertion path.

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