CN115444450A

CN115444450A - Ultrasonic imaging equipment, ultrasonic imaging method and shear wave detection method

Info

Publication number: CN115444450A
Application number: CN202110638941.8A
Authority: CN
Inventors: 李双双
Original assignee: Shenzhen Mindray Bio Medical Electronics Co Ltd
Current assignee: Shenzhen Mindray Bio Medical Electronics Co Ltd
Priority date: 2021-06-08
Filing date: 2021-06-08
Publication date: 2022-12-09

Abstract

According to the ultrasonic imaging equipment, the ultrasonic imaging method and the shear wave detection method, at least one target array element group is selected in an ultrasonic probe according to the depth and the width of an interested area in target tissues, and the focus position and the emission aperture corresponding to the selected at least one target array element group are determined, so that a sound field formed by the at least one target array element group can completely cover the interested area in the target tissues; the sound field is in a divergence shape towards the target tissue, and the focus corresponding to the target array element group is positioned on the other side of the at least one target array element group opposite to the sound field. Because the sound field is divergent towards the target tissue, the region of interest wider than the emission aperture can be covered, and the field of view of the small-size probe is improved. The formed sound field can completely cover the region of interest, so splicing is not needed, the detection speed of the small-size probe for detecting the shear wave is improved, and the accuracy of shear wave capture is improved.

Description

Ultrasonic imaging equipment, ultrasonic imaging method and shear wave detection method

Technical Field

The invention relates to the field of medical instruments, in particular to an ultrasonic imaging device, an ultrasonic imaging method and a shear wave detection method.

Background

Ultrasound elastography is one of the hot spots concerned by clinical research in recent years, mainly reflects elasticity or hardness of tissues, and is increasingly applied to the aspects of auxiliary detection of tissue cancer lesions, benign and malignant discrimination, prognosis recovery evaluation and the like.

Ultrasound elastography mainly images elasticity-related parameters in a region of interest, reflecting the softness and hardness of tissues. Over the last two decades, a number of different elastography methods have emerged, such as quasi-static elastography based on strain caused by the probe pressing against the tissue, shear wave elastography or elastometry based on acoustic radiation force to generate shear waves, transient elastography based on external vibrations to generate shear waves, etc.

Among them, the ultrasonic shear wave elastography method reflects the hardness difference between tissues mainly by a method of generating the propagation of shear waves inside the tissues and detecting the propagation parameters (such as the propagation velocity) thereof. For isotropic elastic tissue, the following relationship exists between the propagation velocity of the shear wave and the elastic modulus of the tissue: young's modulus E =3 ρ Cs ² . It can be seen that there is a one-to-one relationship between shear wave velocity and elastic modulus. Because the method can obtain quantitative hardness measurement results, the diagnosis of doctors is more convenient and objective, and the method is widely concerned and welcomed by the doctors.

In order to accurately calculate the propagation velocity of the shear wave in the region of interest, the system usually needs to obtain the ultrasonic echo information at each time quickly and continuously within a period of time to accurately capture the arrival position of the shear wave at each time, which requires the system to obtain the entire information of the complete range in the region of interest in a very short time. In the conventional ultrasonic imaging detection method, the detectable range of the ultrasonic echo transmitted and received once is narrow, the requirement is difficult to meet, and the detection range is usually widened by transmitting and splicing the echo for multiple times, so that the detection speed is sacrificed and the shear wave capture precision is further influenced.

Some prior arts try to reduce or avoid splicing by using methods such as multi-beam receiving, ultra-wide sound field focusing, plane wave transmitting and receiving, so as to improve the detection speed, but for the case of a small size of the probe itself, such as a micro linear array, a micro small convex, an intracavity probe, a phased array, etc., even if the methods such as multi-beam receiving, ultra-wide sound field focusing, plane wave transmitting and receiving, etc., are adopted, splicing is still needed, so for the small size probe, the detection speed of the shear wave is still not high, thereby affecting the accuracy of final shear wave capture.

Disclosure of Invention

The invention mainly provides an ultrasonic imaging device, an ultrasonic imaging method and a shear wave detection method, which are used for improving the ultrasonic detection speed of a small-size probe.

An embodiment provides a method of detecting shear waves, comprising:

generating shear waves within the target tissue;

selecting at least one target array element group in an ultrasonic probe according to the depth and the width of the region of interest in the target tissue, and determining a focus position and a transmitting aperture corresponding to the at least one selected target array element group, so that a sound field formed by the at least one target array element group can completely cover the region of interest in the target tissue; wherein the sound field diverges toward a target tissue, and the focal point is located on the other side of the at least one target array element group opposite the sound field;

determining the relative delay of the time for transmitting the ultrasonic waves between the array elements in the at least one target array element group, and controlling the array elements in the at least one target array element group to transmit the ultrasonic waves according to the corresponding relative delay, so that the ultrasonic waves transmitted by the array elements in the at least one target array element group are equivalent to be transmitted from the corresponding focuses thereof at the same time, and the sound field is formed;

receiving ultrasonic echoes fed back from the region of interest to obtain echo information of different positions in the region of interest;

transmitting ultrasonic waves for multiple times within the duration time and receiving ultrasonic wave echoes fed back from the region of interest to obtain echo information of different positions in the region of interest corresponding to different moments;

and obtaining the shear wave information corresponding to the interested region according to the echo information of different positions in the interested region corresponding to different moments.

An embodiment provides a method of detecting shear waves, comprising:

generating shear waves within the target tissue;

according to the depth and the width of an interested area in a target tissue, selecting at least one target array element group in an ultrasonic probe in array convex arrangement, and determining a focus position and an emission aperture corresponding to the at least one selected target array element group, so that a sound field formed by the at least one target array element group can completely cover the interested area in the target tissue; the sound field is divergent towards a target tissue, and the focus is positioned at the position of a virtual circle center of a physical area formed by the convex arrangement of the array;

controlling each array element in the at least one target array element group to simultaneously transmit ultrasonic waves to form the sound field;

In the detection method of an embodiment, a width of the region of interest is larger than a width of an ultrasound probe.

In the detection method of an embodiment, a left boundary of the sound field exceeds a central angle of a sector area formed by a portion of the region of interest, and a proportion of the central angle of the sector area formed by the sound field is between 0% and 2.5%; the right boundary of the sound field exceeds the central angle of a sector area formed by the part of the region of interest, and the percentage of the central angle of the sector area formed by the sound field is between 0 and 2.5 percent.

In the detection method of an embodiment, a central angle of a sector area formed by the sound field does not exceed 100 °.

In the method for detecting a light source of an embodiment,

the number of the target array elements selected in the ultrasonic probe is one, and the focus is positioned on the symmetry axis of the region of interest; or,

a plurality of target array elements are selected from the ultrasonic probe, and the symmetry axis of the focus position corresponding to the plurality of target array elements is superposed with the symmetry axis of the region of interest; or,

selecting one target array element group from the ultrasonic probe, wherein the focus corresponding to the target array element group is not positioned on the symmetry axis of the region of interest; or,

the ultrasonic probe comprises a plurality of target array elements, the focus corresponding to each target array element is positioned on the same straight line, and the straight line is a horizontal line or an oblique line.

In the detection method of an embodiment, the selecting at least one target array element group in the ultrasound probe according to the depth and the width of the region of interest in the target tissue includes:

according to the depth and the width of a region of interest in target tissue, only selecting array elements of all pointing angles in an ultrasonic probe towards the region of interest to form at least one target array element group.

In the detection method of an embodiment, before the receiving the ultrasonic echo derived from the feedback of the region of interest and obtaining echo information at different positions in the region of interest, the method further includes:

obtaining a first emission parameter according to the at least one target array element group, the emission aperture thereof and the corresponding focus position;

controlling each array element in the at least one target array element group to transmit a first ultrasonic wave according to the first transmission parameter;

adjusting at least one of the emission deflection angle, the emission aperture and the corresponding focus position of the at least one target array element group to obtain a second emission parameter;

controlling each array element in the at least one target array element group to transmit a second ultrasonic wave according to the second transmission parameter;

the receiving of the ultrasonic echo from the region of interest feedback, and the obtaining of the echo information at different positions in the region of interest includes:

and weighting the echo of the first ultrasonic wave and the echo of the second ultrasonic wave, and acquiring echo information of different positions in the region of interest according to the weighting result.

In the detection method of an embodiment, the receiving the ultrasonic echo derived from the region of interest feedback includes:

receiving ultrasonic echoes fed back by each transverse position of the region of interest at a preset receiving density; the beam spacing corresponding to the receiving density is one of 0.2mm-1 mm.

An embodiment provides an ultrasound imaging method, comprising:

sequentially emitting ultrasonic waves to different transverse positions of a target tissue, wherein a sound field formed by the ultrasonic waves emitted each time is in a divergent shape towards the target tissue, and a focus corresponding to the sound field is positioned on the other side of an ultrasonic probe opposite to the sound field, or the focus corresponding to the sound field is positioned at a virtual circle center position of a physical region formed by convex arrangement of an array of the ultrasonic probes;

and receiving the echoes of the ultrasonic waves, splicing and processing to generate an ultrasonic image.

An embodiment provides a method of ultrasound imaging comprising:

determining a region of interest in the target tissue;

according to the depth and the width of an interested area in a target tissue, selecting at least one target array group in an ultrasonic probe, and determining a focus position corresponding to the at least one selected target array group and the emission aperture of each target array group, so that a sound field formed by the at least one target array group can completely cover the interested area in the target tissue;

controlling each array element in the at least one target array element group to emit ultrasonic waves to form the sound field, receiving ultrasonic wave echoes from the region of interest feedback, and obtaining echo information of different positions in the region of interest;

generating an ultrasonic image according to the echo information;

wherein the sound field diverges toward a target tissue, and the focal point is located on the other side of the at least one target array element group opposite the sound field; or the depth of the focus is deeper than that of the region of interest; or, a plurality of target array elements are selected from the ultrasonic probe, the depth of the focus position corresponding to each target array element does not exceed the depth of the region of interest, and the width formed by arranging all the focuses along the width direction is larger than the width of the region of interest; or the focus is positioned at the position of a virtual circle center of a physical area formed by the convex arrangement of the array of the ultrasonic probe.

An embodiment provides an ultrasound imaging apparatus comprising:

an ultrasonic probe;

the transmitting/receiving control circuit is used for controlling the ultrasonic probe to transmit ultrasonic waves to a region of interest and receive echoes of the ultrasonic waves;

a memory for storing a program;

a processor for executing the program in the memory to implement the method as described above.

An embodiment provides a computer readable storage medium having a program stored thereon, the program being executable by a processor to implement a method as described above.

According to the ultrasonic imaging device, the ultrasonic imaging method and the shear wave detection method of the embodiment, at least one target array element group is selected in the ultrasonic probe according to the depth and the width of the region of interest in the target tissue, and the focus position and the emission aperture corresponding to the selected at least one target array element group are determined, so that the region of interest in the target tissue can be completely covered by a sound field formed by the at least one target array element group; wherein the sound field diverges towards the target tissue and the focus is on the other side of the at least one target array element from the sound field. Because the sound field is divergent towards the target tissue, the region of interest wider than the emission aperture can be covered, and the field of view of the small-size probe is improved. The formed sound field can completely cover the region of interest, so splicing is not needed, the detection speed of the small-size probe for detecting the shear wave is improved, and the accuracy of shear wave capture is improved.

Drawings

FIG. 1 is a flow chart of one embodiment of a method for detecting shear waves according to the present invention;

FIG. 2 is a schematic diagram of a target array group emitting ultrasonic waves to form a sound field detection region of interest in the shear wave detection method provided by the present invention;

FIG. 3 is a schematic diagram of a target array group emitting ultrasonic waves to form a sound field detection region of interest in the shear wave detection method provided by the present invention;

fig. 4 is a schematic diagram of a target array element group emitting ultrasonic waves to form a sound field detection region of interest in the shear wave detection method provided by the present invention;

FIG. 5 is a schematic diagram of a target array group emitting ultrasonic waves to form a sound field detection region of interest in the shear wave detection method provided by the present invention;

FIG. 6 is a schematic diagram of a plurality of target array elements emitting ultrasonic waves to form a sound field detection region of interest in the shear wave detection method provided by the present invention;

FIG. 7 is a flow chart of an embodiment of step 3 of the method for detecting shear waves according to the present invention;

fig. 8 is a schematic diagram of the transmission delay of each array element in the shear wave detection method provided in the present invention;

fig. 9 is a schematic diagram of ultra-wide beam reception in the shear wave detection method according to the present invention;

fig. 10 is a schematic diagram of ultra-wide beam reception in the shear wave detection method according to the present invention;

FIG. 11 is a flow chart of an embodiment of step 3 of the method for detecting shear waves according to the present invention;

FIG. 12 is a schematic diagram of a region of interest for detecting a sound field formed by transmitting ultrasonic waves with a first transmission parameter in a shear wave detection method according to the present invention;

FIG. 13 is a schematic diagram of a region of interest for detecting a sound field formed by transmitting ultrasonic waves with a second transmission parameter in the method for detecting shear waves provided by the present invention;

FIG. 14 is a flow chart of one embodiment of a method of ultrasound imaging provided by the present invention;

FIG. 15 is a flow chart of one embodiment of a method of ultrasound imaging provided by the present invention;

fig. 16 is a block diagram of an ultrasound imaging apparatus according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the following detailed description and accompanying drawings. Wherein like elements in different embodiments are numbered with like associated elements. In the following description, numerous details are set forth in order to provide a better understanding of the present application. However, those skilled in the art will readily recognize that some of the features may be omitted or replaced with other elements, materials, methods in different instances. In some instances, certain operations related to the present application have not been shown or described in detail in order to avoid obscuring the core of the present application from excessive description, and it is not necessary for those skilled in the art to describe these operations in detail, so that they may be fully understood from the description in the specification and the general knowledge in the art.

Furthermore, the described features, operations, or characteristics may be combined in any suitable manner to form various embodiments. Also, the various steps or actions in the method descriptions may be transposed or transposed in order, as will be apparent to one of ordinary skill in the art. Thus, the various sequences in the specification and drawings are for the purpose of describing certain embodiments only and are not intended to imply a required sequence unless otherwise indicated where such sequence must be followed.

The numbering of the components as such, e.g., "first", "second", etc., is used herein only to distinguish the objects as described, and does not have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings).

The ultrasonic imaging equipment and the shear wave detection method provided by the invention have the advantages that after shear wave propagation is generated in a target area, ultrasonic waves are continuously transmitted and detected to tissues and echo signals of the ultrasonic waves are received in sequence within a certain time, at the moment, transmitting focusing parameters are set according to the size and the position of an interested area, a negative focusing point positioned behind a probe is formed, a fan-shaped ultrasonic transmitting sound field which completely covers or exceeds the width of the interested area is formed, ultrasonic echo data of ultra-wide wave beams are received, and shear wave propagation information in the large-range interested area is rapidly obtained. By the method, the ultrasonic detection range can greatly exceed the width range corresponding to the size of the probe, the method is very suitable for detecting the shear wave of a large interested target by a small-size probe, and the system detection frame rate can be effectively improved, so that the shear wave propagation process is detected at a higher time sampling rate, and the shear wave propagation speed is more accurately calculated. Of course, the method of the present invention can also be applied to other imaging modes, and the frame rate of ultrasonic imaging is improved.

As shown in fig. 1, the method for detecting shear waves provided by the present invention includes the following steps:

step 1, generating shear waves in target tissues. The generated shear wave can generate transverse propagation of the shear wave in the target tissue through an acoustic radiation force effect, and can also generate the shear wave longitudinally transmitted to the target tissue at a certain depth from the body surface in an external vibration mode. In either method, the range of propagation of shear waves in tissue is relatively wide. Especially when the size of the ultrasonic probe is small, the propagation range of the shear wave tends to exceed the width corresponding to the size of the probe. However, since the region of interest through which the shear wave propagates can be theoretically detected as the target of interest, the region of interest in which the shear wave is detected is also generally set to a wide range. The core of the invention is to provide an innovative detection technology, so as to realize the rapid detection of the region of interest exceeding the size of the probe.

The region of interest may be determined automatically or manually, for example, before or after generating shear waves inside the target tissue (before step 2), and further includes step S1':

controlling an ultrasonic probe to emit ultrasonic waves to target tissues and receiving echoes of the ultrasonic waves; generating an ultrasonic image according to the echo of the ultrasonic wave and displaying the ultrasonic image; the region of interest may be automatically determined according to the ultrasound image, or may be determined based on an input operation of a user (for example, the user frames the region of interest on the ultrasound image through a human-computer interaction device).

And 2, selecting at least one target array element group in the ultrasonic probe according to the depth and the width of the region of interest in the target tissue, and determining a focus position and a transmitting aperture corresponding to the at least one selected target array element group, so that a sound field formed by the at least one target array element group can completely cover the region of interest in the target tissue. The invention is suitable for the condition that the sum of the emission apertures of all target array element groups is smaller than the width of the interested area, and a large emission aperture is generally selected as much as possible, so that the width of the interested area is usually larger than the width of the ultrasonic probe, and the whole sound field formed by all the target array element groups is divergent towards the target tissue. The ultrasonic probe can adopt full aperture transmission to maximize the sound field; certainly, in some cases, considering that the shape curvature of some ultrasound probes is large, when the angle difference of each array element of the probe is large, due to the limitation of the pointing angle of the array element, the full aperture is not the best choice, and the remote array elements may not only enhance the sound field intensity but also increase the noise, so that only the array elements of all pointing angles towards the region of interest in the ultrasound probe may be selected to form at least one target array element group according to the depth and width of the region of interest in the target tissue (as shown in fig. 5). For a convex array or a concave array, part of array elements may face the region of interest, and for a planar array, all the array elements face the region of interest, so the planar array can select a full aperture.

As shown in fig. 2 to 6, in the present embodiment, the target array element group is divided by the focal point, that is, one or more array elements forming a focal point are one target array element group; in other words, one target array group has only one focal point (black dots in the figure), which is located on the other side of the at least one target array group opposite to the sound field, i.e. the sound field is located on one side of the target array group, and the focal point is located on the other side of the target array group. From the direction of the array elements emitting ultrasonic waves, the sound field is in front of the target array element group, and the focus is behind the target array element group. Since the focus is located behind the target array group, the focus is a virtual focus, and the sound field formed by the ultrasonic waves emitted by the target array group is equivalent to the sound field formed by the ultrasonic waves emitted from the focus, in other words, the sound field formed by the ultrasonic waves emitted by the target array group is focused reversely on the focus.

In the same transmission, according to the information of the position, the depth, the width and the like of the region of interest, the focus position of each selected target array group and the corresponding transmission aperture are determined, and the final purpose is to ensure that the region of interest is completely covered by the range of the whole transmission sound field. The selection(s) of the target array element group, the emission parameters such as the emission aperture and the focus position are not limited to one combination, and the sound field covering the region of interest may be formed by several combinations, as shown in fig. 2 to 6. The ultrasonic imaging equipment can set an optimal rule in advance according to experience so as to ensure that the sound field in the region of interest reaches a comprehensive optimal state in the aspects of energy intensity, width, uniformity and the like. The following is a detailed description of several combinations:

as shown in fig. 2-5, only one target array element may be selected in the ultrasound probe. As shown in fig. 2, full aperture transmission (i.e., using all probe elements) can be selected to boost the transmit energy. As shown in fig. 3 and fig. 5, non-full aperture transmission may also be selected, and for example, as shown in fig. 5, partial array elements aligned with the region of interest may be selected as much as possible to form a target array element group to participate in transmission. As shown in fig. 2, 3 and 5, the focus corresponding to the target array element group is located on the symmetry axis of the region of interest, so that the energy distribution of the sound field in the region of interest is as uniform as possible, and if the ultrasound probe is located right above the region of interest, the focus is also located on the symmetry axis of the ultrasound probe. Of course, as shown in fig. 4, the focal point corresponding to the target array element group is not located on the symmetry axis of the region of interest. The height position of the focal point is related to the transmit aperture, with higher focal points (further from the probe) having larger transmit apertures (as in fig. 2) and lower focal points (closer to the probe) having smaller transmit apertures (as in fig. 3). The horizontal position of the focal point affects the symmetry of the sound field with the region of interest, as shown in fig. 3 and 4.

In some embodiments, a more complex focusing approach may be used in order to maximize the uniformity within the fan-shaped acoustic field, as shown in fig. 6. Multiple focal points are used, i.e. the array elements within the entire transmit aperture are further divided into groups, forming multiple target array elements (3 in fig. 6), i.e. there are multiple focal points. Generally speaking, the focuses corresponding to each target array element group are distributed on the same straight line, and if the focuses corresponding to each target array element group are symmetrical about the symmetry axis of the region of interest, that is, the symmetry axis of each focus coincides with the symmetry axis of the region of interest, the straight line is a horizontal line; of course, the straight line may also be set as a diagonal line, so that the entire sound field is not symmetrical to the region of interest.

Whether the target array element group or a plurality of target array element groups are adopted, in the whole formed fan-shaped sound field, the energy of the part close to the boundary of the sound field is relatively weaker and is distributed unevenly, so that the range of the boundary of the sound field is controlled to be slightly larger than that of the region of interest, namely, the left boundary and the right boundary of the sound field both exceed the region of interest, the energy in the region of interest can be ensured to be higher as much as possible so as to ensure the detection sensitivity, and the signal attenuation wave of the edge of the sound field and the region of interest are avoided. Of course, as shown in fig. 4, the sector-shaped sound field described herein is not necessarily an absolute sector shape, but is substantially sector-shaped due to the influence of the focal position and the probe morphology.

In one embodiment, as shown in fig. 2, the ratio of the central angle of the sector area formed by the part of the left boundary of the sound field exceeding the region of interest to the central angle of the sector area of less than 2 in the sector area formed by the sound field is between 0% and 2.5%. The central angle < 3 of a sector area formed by the part of the right boundary of the sound field exceeding the region of interest, and the ratio of the central angle < 1 of the sector area formed by the sound field is between 0% and 2.5%. The central angle 1 of a sector area formed by the whole sound field is not more than 100 degrees. Thus, a good balance between the field energy intensity and uniformity can be achieved.

And 3, controlling each array element in the at least one target array element group to transmit ultrasonic waves to form the sound field, and receiving ultrasonic wave echoes fed back from the region of interest to obtain echo information of different positions in the region of interest.

If the ultrasonic probe is a planar array (as shown in fig. 2-4), a concave array or a convex array but the focus is not located at the focus of the convex array, in order to achieve the effect of virtual emission of ultrasonic waves from the focus, the time for transmitting the ultrasonic waves by each array element needs to be adjusted, specifically as shown in fig. 7, step 3 includes:

step 321, determining the relative delay (i.e. the transmission sequence, the relative time interval, etc.) of the transmission time of the ultrasonic wave between each array element in the at least one target array element group. For example, according to the geometric form of the ultrasound probe, the time difference of the ultrasonic wave emitted from the focal point to reach each array element (that is, the time difference of the ultrasonic wave emitted from each array element to reach the focal point position) is calculated according to the distance between each array element in each target array element group and the corresponding focal point, and of course, the ultrasonic wave emitted from the actual array element does not reach the focal point, and the calculation is performed in an assumed manner here; compensating the transmission start time of the array elements according to the calculated time difference to make the time lengths of the ultrasonic waves transmitted by the array elements from the focal point consistent, thereby determining the relative delay of the ultrasonic wave transmission time between the array elements in the at least one target array element group, as shown in fig. 8.

And 322, controlling each array element in the at least one target array element group to transmit ultrasonic waves according to the corresponding relative delay, so that the ultrasonic waves transmitted by each array element in the at least one target array element group are transmitted from the corresponding focus at the same time to form the sound field, thereby causing the effect of negative transmission and aggregation. It can be seen that in contrast to conventional positive focusing, the central array element is transmitted first and the edge-wise array elements are transmitted later. It is also noted that the ultrasound waves do not actually reach the negative focus position.

And 323, receiving the ultrasonic echoes fed back by each transverse position of the region of interest at a preset receiving density. The receiving density can be set according to requirements, and generally, the receiving density corresponds to one of the beam spacing of 0.2mm-1 mm.

As shown in fig. 5, if the ultrasonic probe adopts a convex array, that is, the array elements are arranged in a convex manner, and the focal point is located at a virtual center position of a physical region formed according to the convex arrangement of the array, for example, the circular arc array, and the center position of the circular arc array is also the position of the focal point, then there is no need to transmit in a delayed manner, each array element in the at least one target array element group is controlled to transmit ultrasonic waves at the same time, so as to form the sound field, and ultrasonic echoes fed back from the region of interest are received, so as to obtain echo information at different positions in the region of interest, and the specific process of receiving can be synchronized at step 323.

Since the transmitted energy covers the entire range of the region of interest, the ultrasound probe can perform ultra-wide beam reception at various lateral positions of the region of interest, as shown in fig. 9 and 10, shear waves laterally propagate through the region of interest, and the received beams obtained by one transmission contain ultrasound echo signals from multiple lateral positions in the region of interest. Although the emitted sound field is fan-shaped, the receiving positions may be arranged in a fan-shaped arrangement (as shown in fig. 10) or in a regular parallel arrangement (such as a vertical straight arrangement as shown in fig. 9). The number of receiving positions (in the lateral direction) may be determined as required by the calculation. In order to accurately capture the propagation position of the shear wave, it is preferable to use a high-density (i.e., the width interval between beams is set to be small) reception method, for example, the beam interval is set to be 0.2mm. Of course, in order to reduce the amount of calculation, the spacing between the beams may be enlarged as needed, such as 0.4mm, 0.6mm, 1mm, etc. The detection beams represent the ultrasound echo signals obtained at the corresponding positions, which may be arranged in parallel (see fig. 9) or in a fan shape (see fig. 10). When the fan-shaped arrays are arranged, the spacing between the detection beams is angularly separated, for example, by 1 degree, 0.6 degree, etc. It can be seen that when the shear wave propagates in the region of interest, the overall position of the shear wave in the region of interest can be calculated by one transmission and reception.

In addition, in order to further improve the quality of the received echo signal, different deflection angles, different transmitting apertures, or transmitting focuses at different positions can be sequentially selected during transmitting, and weighting processing can be performed on the echo signals obtained under different parameter settings, so as to improve the signal-to-noise ratio of the echo signals. Specifically, in an embodiment, as shown in fig. 11, step 3 specifically includes:

and 31, obtaining a first transmission parameter according to the at least one target array element group, the transmission aperture thereof and the corresponding focus position. The first transmission parameters comprise transmission deflection angle, relative time delay and the like. The specific process of obtaining the relative delay is shown in step 321, which is not described herein.

And step 32, controlling each array element in the at least one target array element group to transmit a first ultrasonic wave according to the first transmission parameter to form the sound field, and receiving an ultrasonic wave echo from the region of interest feedback. As shown in fig. 12, the specific process is shown in

steps

322 and 323, which are not described herein.

And step 33, adjusting at least one of the emission deflection angle, the emission aperture and the corresponding focus position of the at least one target array element group (for example, adjusting the focus position in fig. 13), and obtaining a second emission parameter. Similarly, the second transmission parameter includes a transmission deflection angle, a relative delay time, and the like. The specific process of obtaining the relative delay is shown in step 321, which is not described herein.

And step 34, controlling each array element in the at least one target array element group to transmit a second ultrasonic wave according to the second transmission parameter to form the sound field, and receiving an ultrasonic wave echo from the region of interest feedback. The specific process is shown in

steps

322 and 323, which are not described herein.

And step 35, performing weighting processing on the echo of the first ultrasonic wave and the echo of the second ultrasonic wave, and obtaining echo information of different positions in the region of interest according to the result of the weighting processing. As can be seen from fig. 12 and 13, the echo signals obtained from two different focus positions and the emission deflection direction are accumulated, so that the signal quality is effectively improved.

And 4, transmitting ultrasonic waves for multiple times and receiving ultrasonic wave echoes fed back from the region of interest within the duration time to obtain echo information of different positions in the region of interest corresponding to different moments. In one embodiment, each of the plurality of transmissions may be achieved by repeating step 3. For example, if step 3 does not adopt a weighting form, the transmission parameters of each transmission in this step may be the same; namely, each emission in the multiple emissions transmits the ultrasonic wave according to the relative delay of the ultrasonic wave transmitting time among the array elements in the at least one target array element group. If the step 3 adopts a weighting mode, repeating the step 3 for a plurality of times within the duration, and finally obtaining the echo information of different positions of the interested region within a preset duration.

Due to the ultra-wide transmitting sound field and the wide beam receiving mode, the time interval of adjacent 2 times of repeated transmitting and receiving (detecting) is as small as possible, so that the dynamic capturing precision of the shear wave is improved as much as possible, and the shear wave signals in the region of interest can be captured timely and comprehensively no matter whether the tissue is soft or hard (corresponding to the slow or fast propagation speed of the shear wave).

And 5, obtaining shear wave information (such as the propagation speed, young modulus and/or shear modulus and the like) corresponding to the region of interest according to the echo information. Specifically, the shear wave information corresponding to the region of interest is obtained according to the echo information of different positions in the region of interest corresponding to different times. When step 4 is performed with repeated detection on the region of interest for a period of time (for example, several ms or several tens ms) (the ultrasound transmitting and receiving process is repeated on the same target, and the change of the target tissue within a period of time is recorded), the change of the position of the shear wave in the region of interest at different moments can be obtained, or the time difference of the shear wave in the region of interest passing through any two transverse positions can be obtained, so as to calculate the propagation velocity of the shear wave at each position in the region of interest. Since there is a specific relationship between the propagation speed Cs of shear waves in tissue and the elastic modulus of tissue: young modulus E =3 rho Cs ^2, and shear modulus G = rho Cs ^2, wherein rho is tissue density, and imaging or calculating the elasticity characteristic quantity of the tissue can be further realized. So that shear wave information can be displayed on the display. And generating and displaying a corresponding ultrasonic image according to the echo information.

The invention has great innovation value for rapidly detecting the shear wave propagation of a large-range region of interest under a small-size probe. The calculation method of the negative focusing enables the ultrasonic imaging equipment to conveniently calculate focusing related parameters according to the position of the region of interest relative to the probe, the size of the region of interest and the like, and a proper sound field is formed. The invention belongs to an innovative ultrasonic emission detection method, which is not only suitable for a shear wave imaging mode, but also suitable for other imaging modes, such as B-type imaging, color blood flow and other imaging. The following is a detailed description of ultrasound imaging.

The negative focusing mode of the present invention can be adopted to perform ultrasonic imaging by combining splicing, as shown in fig. 14, and the ultrasonic imaging method provided by the present invention comprises the following steps:

step 1', sequentially transmitting ultrasonic waves to different transverse positions of a target tissue, wherein a sound field formed by the ultrasonic waves transmitted each time is in a divergent shape (namely a fan-shaped sound field with a focus) towards the target tissue, and the focus corresponding to the sound field is positioned on the other side of an ultrasonic probe opposite to the sound field, or the focus corresponding to the sound field is positioned at the position of a virtual circle center of a physical region formed by the convex arrangement of the array of the ultrasonic probe.

And 2', receiving the echo of the ultrasonic wave, splicing, generating an ultrasonic image and displaying the ultrasonic image on a display.

For example, in a B image, it is usually necessary to sequentially transmit ultrasonic waves to different lateral positions in the field of view of the probe and to perform processing such as stitching on ultrasonic echoes to obtain a complete image. According to the invention, because the range of the tissue information acquired by single transmission and reception is larger, the transmission times required for obtaining a complete frame image are reduced, and the imaging frame rate is effectively improved.

For example, in C-type imaging, it is usually necessary to sequentially transmit a plurality of ultrasonic waves to different lateral positions in a region of interest and receive ultrasonic echoes to calculate the blood flow velocity of the corresponding position, and then perform processing such as stitching on velocity results calculated at the positions to obtain a complete frame of color blood flow image. According to the invention, because the range of the tissue information acquired by single transmission and reception is larger, the transmission times required for obtaining a complete frame image are reduced, and the imaging frame rate is effectively improved.

Of course, the ultrasound imaging may also be performed without using a splicing method, as shown in fig. 15, the ultrasound imaging method provided by the present invention includes the following steps:

step 1', a region of interest in a target tissue is determined. The region of interest can be determined automatically or manually, for example, an ultrasonic probe is controlled to transmit ultrasonic waves to the target tissue and receive echoes of the ultrasonic waves; generating an ultrasonic image according to the echo of the ultrasonic wave and displaying the ultrasonic image; the region of interest may be automatically determined according to the ultrasound image, or may be determined based on an input operation of a user (for example, the user frames the region of interest on the ultrasound image through a human-computer interaction device).

Step 2', at least one target array element group is selected in the ultrasonic probe according to the depth and the width of the region of interest in the target tissue, and the focus position corresponding to the at least one selected target array element group and the emission aperture of each target array element group are determined, so that the region of interest in the target tissue can be completely covered by the sound field formed by the at least one target array element group. In the embodiment shown in fig. 15, the focal point may be a positive focal point (where the ultrasonic waves are actually focused) of the ultrasonic wave focusing, or may be a focal point in the above-described embodiment of the reverse focusing. For a positive focus, the depth may be deeper than the depth of the region of interest, so that the sound field completely covers the region of interest. Of course, when a plurality of target array elements are selected in the ultrasound probe, the depth of the focal position corresponding to each target array element does not exceed the depth of the region of interest, and the width formed by arranging all the focal points along the width direction is greater than the width of the region of interest, so that the sound field can completely cover the region of interest. For the case that the focal point is the focal point in the above embodiment, as shown in fig. 2 to 6, the sound field is divergent toward the target tissue, and the focal point is located on the other side of the at least one target array element group opposite to the sound field, or the focal point is located at the virtual center position of the physical region formed according to the array convex arrangement of the ultrasonic probe, which is specifically referred to the above embodiment of shear wave detection, and is not described herein again.

And 3', controlling each array element in the at least one target array element group to transmit ultrasonic waves to form the sound field, and receiving ultrasonic wave echoes fed back from the region of interest to obtain echo information of different positions in the region of interest. For the focus, the specific process is the same as step 3, which is not described herein.

And 4', generating an ultrasonic image according to the echo information and displaying the ultrasonic image on a display.

Therefore, the imaging method can cover the whole region of interest by one-time emission, improve the imaging frame rate, and particularly enlarge the coverage area of a sound field by forming a fan-shaped sound field, so that the probe with insufficient emission aperture can also cover the whole region of interest, and the use scene of the probe is enlarged.

The various methods described above may be implemented by an ultrasound imaging apparatus, as shown in fig. 16, comprising: an ultrasound probe 30, a transmit/receive control circuit 40, a processor 20, a memory 80 and a human-computer interaction device 70.

The ultrasonic probe 30 includes a transducer (not shown) composed of a plurality of array elements arranged in an array, the plurality of array elements are arranged in a row to form a linear array, or are arranged in a two-dimensional matrix to form an area array, and the plurality of array elements may also form a convex array. The array elements are used for transmitting ultrasonic waves according to the excitation electric signals or converting the received ultrasonic waves into electric signals. Each array element can be used to convert the electrical pulse signal and the ultrasonic wave into each other, so that the ultrasonic wave can be transmitted to the object to be imaged, and the echo of the ultrasonic wave reflected by the tissue can be received. In the ultrasonic detection, it can be controlled by the transmission control circuit 410 and the reception control circuit 420 which array elements are used for transmitting ultrasonic waves and which array elements are used for receiving ultrasonic waves, or the time slots of the array elements are controlled for transmitting ultrasonic waves or receiving echoes of ultrasonic waves. The array elements participating in ultrasonic wave transmission can be simultaneously excited by the electric signals, so that the ultrasonic waves are transmitted simultaneously; or the array elements participating in the ultrasonic wave transmission can be excited by a plurality of electric signals with certain time intervals, so that the ultrasonic waves with certain time intervals are continuously transmitted.

The array elements, for example, using piezoelectric crystals, convert the electrical signals into ultrasound signals according to a transmit sequence transmitted by the transmit control circuitry 410, which may include one or more scan pulses, one or more reference pulses, one or more push pulses, and/or one or more doppler pulses, depending on the application. The ultrasonic signals include focused waves, plane waves, divergent waves, and the like according to the morphology of the waves.

The user transmits ultrasonic waves to an object to be imaged (generally, a region of interest in biological tissue) 10 by moving the ultrasonic probe 30 to select an appropriate position and angle, receives echoes of the ultrasonic waves returned by the object to be imaged 10, and outputs ultrasonic echo signals, which are channel analog electrical signals formed by taking the receiving array elements as channels and carry amplitude information, frequency information and time information.

The transmission control circuit 410 is configured to generate a transmission sequence according to the control of the processor 20, where the transmission sequence is configured to control some or all of the plurality of array elements to transmit ultrasonic waves to the object to be imaged, and the transmission sequence parameters include the position of the array element for transmission, the number of array elements, and ultrasonic beam transmission parameters (such as amplitude, frequency, transmission times, transmission interval, transmission angle, wave pattern, focusing position, etc.). In some cases, the transmit control circuitry 410 is further configured to phase delay the transmitted beams so that different transmit elements transmit ultrasound at different times. In different operation modes, such as a B image mode, a C image mode, and a D image mode (doppler mode), the parameters of the transmit sequence may be different, and the echo signals received by the receive control circuit 420 and processed by the subsequent modules and corresponding algorithms may generate a B image reflecting the anatomical structure of the tissue, a C image reflecting the blood flow information, and a D image reflecting the doppler spectrum image.

The receiving control circuit 420 is configured to receive the ultrasonic echo signal from the ultrasonic probe 30 and process the ultrasonic echo signal. The receive control circuit 420 may include one or more amplifiers, analog-to-digital converters (ADCs), and the like. The amplifier is used for amplifying the received echo signal after proper gain compensation, and the amplifier is used for sampling the analog echo signal according to a preset time interval so as to convert the analog echo signal into a digitized echo signal, wherein amplitude information, frequency information and phase information are still reserved in the digitized echo signal. The data output by the reception control circuit 420 may be output to the processor 20 for processing or output to the memory 80 for storage.

The processor 20 may be in signal connection with the receiving control circuit 420, and is configured to perform beamforming processing such as delaying and weighted summing on the echo signals, where due to different distances from the ultrasonic receiving point in the measured tissue to the receiving array elements, channel data of the same receiving point output by different receiving array elements has a delay difference, and needs to be delayed, phase-aligned, and weighted summing on different channel data of the same receiving point, so as to obtain beamformed ultrasound image data, which is also referred to as radio frequency data (RF data).

The processor 20 may also remove the signal carrier by IQ demodulation, extract the tissue structure information contained in the signal, and perform filtering to remove noise, where the acquired signal is referred to as a baseband signal (IQ data pair).

The processor 20 may be configured as a central controller Circuit (CPU), one or more microprocessors, a graphics controller circuit (GPU), or any other electronic component capable of processing input data according to specific logic instructions, which may perform control of peripheral electronic components according to the input instructions or predetermined instructions, or perform data reading and/or saving on the memory 80, or may process input data by executing programs in the memory 80, such as performing one or more processing operations on acquired ultrasound data according to one or more operating modes, including but not limited to adjusting or defining the form of ultrasound waves emitted by the ultrasound probe 30, generating various image frames for display by a display of a subsequent human machine interaction device 70, or adjusting or defining the content and form of display on the display, or adjusting one or more image display settings (e.g., ultrasound images, interface components, regions of interest) displayed on the display.

The acquired ultrasound data may be processed by the processor 20 in real time during the scan as the echo signals are received, or may be temporarily stored on the memory 80 and processed in near real time in an online or offline operation.

In this embodiment, the processor 20 controls the operations of the transmission control circuit 410 and the reception control circuit 420, for example, controls the transmission control circuit 410 and the reception control circuit 420 to operate alternately or simultaneously. The processor 20 may also determine an appropriate operation mode according to the selection of the user or the setting of the program, form a transmission sequence corresponding to the current operation mode, and send the transmission sequence to the transmission control circuit 410, so that the transmission control circuit 410 controls the ultrasound probe 30 to transmit the ultrasound wave using the appropriate transmission sequence.

The processor 20 is also configured to process the ultrasound echo signals to generate a gray scale image of the signal intensity variations over the scan range, which reflects the anatomical structure inside the tissue, referred to as a B-image. The processor 20 may output the B image to a display of the human-computer interaction device 70 for display.

The human-computer interaction device 70 is used for performing human-computer interaction, namely outputting visual information and receiving input of a user; the input of the user can be received by a keyboard, an operating button, a mouse, a track ball, a touch pad and the like, and a touch screen integrated with a display can also be adopted; the display can be used for outputting visual information.

In the present invention, the processor 20 may execute a program in memory to implement the above-described method by controlling the ultrasound imaging device. For example, in step 1, the processor 20 may control the ultrasonic probe or the vibrating head to vibrate to generate the shear wave, and may also control the ultrasonic probe to emit the ultrasonic wave to focus, so as to generate the transverse propagation of the shear wave inside the target tissue through the acoustic radiation force effect. For example, in

steps

3, 4, 1', 2', and 3", the processor 20 controls the ultrasound probe 30 to transmit ultrasound waves and receive echoes through the transmit/receive control circuit 40. The other steps of the method described above may then be performed directly by the processor 20. The specific processes of performing ultrasound imaging and detecting shear waves by the ultrasound imaging device are described in detail in the above method embodiments, and are not described herein again.

In summary, in the shear wave imaging, after the shear wave generated in the tissue propagates, the ultrasonic imaging apparatus sequentially and continuously transmits a series of detection ultrasonic waves to the region of interest within a certain time period, receives corresponding echo signals, and obtains and displays the elastic characteristic quantity in the region of interest through a shear wave elastography calculation link. In the transmission and reception of the detection ultrasonic waves, the system transmits the ultrasonic waves to the human body through special transmission focusing control parameters to form a negative focusing point behind the probe, forms an ultra-wide sound field (for example, the width is larger than the size of the probe) in an interested area, and receives corresponding ultrasonic echo signals to obtain the human body information in an ultra-wide range. The invention can obtain a large range of human body information by using less emission times, which is equivalent to greatly improving the detection frame rate, so that the target tissue information at each moment can be obtained within the detection time with higher time resolution, thereby accurately calculating the propagation position of the shear wave at each moment and finally calculating the propagation speed at each position.

Reference is made herein to various exemplary embodiments. However, those skilled in the art will recognize that changes and modifications may be made to the exemplary embodiments without departing from the scope hereof. For example, the various operational steps, as well as the components used to perform the operational steps, may be implemented in differing ways depending upon the particular application or consideration of any number of cost functions associated with operation of the system (e.g., one or more steps may be deleted, modified or incorporated into other steps).

Additionally, as will be appreciated by one skilled in the art, the principles herein may be reflected in a computer program product on a computer readable storage medium, which is pre-loaded with computer readable program code. Any tangible, non-transitory computer-readable storage medium may be used, including magnetic storage devices (hard disks, floppy disks, etc.), optical storage devices (CD-ROMs, DVDs, blu Ray disks, etc.), flash memory, and/or the like. These computer program instructions may be loaded onto a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions which execute on the computer or other programmable data processing apparatus create means for implementing the functions specified. These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including means for implementing the function specified. The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified.

While the principles herein have been illustrated in various embodiments, many modifications of structure, arrangement, proportions, elements, materials, and components and otherwise, used in the practice of the disclosure, which are particularly adapted to specific environments and operative requirements, may be employed without departing from the principles and scope of the present disclosure. The above modifications and other changes or modifications are intended to be included within the scope of this document.

The foregoing detailed description has been described with reference to various embodiments. However, one skilled in the art will recognize that various modifications and changes may be made without departing from the scope of the present disclosure. Accordingly, the disclosure is to be considered in an illustrative and not a restrictive sense, and all such modifications are intended to be included within the scope thereof. Also, advantages, other advantages, and solutions to problems have been described above with regard to various embodiments. However, the benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential. As used herein, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, system, article, or apparatus. Furthermore, the term "coupled," and any other variation thereof, as used herein, refers to a physical connection, an electrical connection, a magnetic connection, an optical connection, a communicative connection, a functional connection, and/or any other connection.

Those skilled in the art will recognize that many changes may be made to the details of the above-described embodiments without departing from the underlying principles of the invention. Accordingly, the scope of the invention should be determined from the following claims.

Claims

1. A method of detecting shear waves, comprising:

generating shear waves within the target tissue;

2. A method of detecting shear waves, comprising:

generating shear waves inside the target tissue;

according to the depth and the width of an interested area in target tissue, selecting at least one target array element group in the ultrasonic probe arranged in an array convex mode, and determining a focus position and a transmitting aperture corresponding to the at least one selected target array element group, so that a sound field formed by the at least one target array element group can completely cover the interested area in the target tissue; the sound field is in a divergence shape towards a target tissue, and the focus is located at the position of a virtual circle center of a physical area formed according to the convex arrangement of the array;

controlling each array element in the at least one target array element group to simultaneously transmit ultrasonic waves so as to form the sound field;

3. A method of testing as claimed in claim 1 or 2, wherein the width of the region of interest is greater than the width of an ultrasound probe.

4. The detection method according to claim 1 or 2, characterized in that the left border of the sound field exceeds the central angle of a sector formed by the part of the region of interest, and the percentage of the central angle of the sector formed by the sound field is between 0% and 2.5%; the right boundary of the sound field exceeds the central angle of a sector area formed by the part of the region of interest, and the percentage of the central angle of the sector area formed by the sound field is between 0 and 2.5 percent.

5. The detection method according to claim 1 or 2, wherein the central angle of a sector area formed by the acoustic field is not more than 100 °.

6. The detection method according to claim 1,

one target array element group is selected from the ultrasonic probe, and the focus is positioned on the symmetry axis of the region of interest; or,

a plurality of target array elements are selected from the ultrasonic probe, and the symmetry axes of the focuses corresponding to the plurality of target array elements are superposed with the symmetry axis of the region of interest; or,

7. The detection method as claimed in claim 2, wherein said selecting at least one target array element group in the ultrasound probe according to the depth and width of the region of interest in the target tissue comprises:

8. The method for detecting according to claim 1 or 2, wherein before receiving the ultrasonic echo derived from the feedback of the region of interest and obtaining echo information of different positions in the region of interest, the method further comprises:

9. The method for detecting according to claim 1 or 2, wherein said receiving an ultrasonic echo derived from said region of interest feedback comprises:

receiving ultrasonic echoes fed back by each transverse position of the region of interest at a preset receiving density; the beam spacing corresponding to the receiving density is one of 0.2mm to 1 mm.

10. An ultrasound imaging method, comprising:

sequentially emitting ultrasonic waves to different transverse positions of a target tissue, wherein a sound field formed by the ultrasonic waves emitted each time is in a divergent shape towards the target tissue, and a focus corresponding to the sound field is positioned on the other side of an ultrasonic probe opposite to the sound field, or the focus corresponding to the sound field is positioned at a virtual circle center position of a physical region formed according to convex array arrangement of the ultrasonic probes;

11. An ultrasound imaging method, comprising:

determining a region of interest in the target tissue;

selecting at least one target array element group in an ultrasonic probe according to the depth and the width of the region of interest in the target tissue, and determining a focus position corresponding to the at least one selected target array element group and a transmitting aperture of each target array element group, so that a sound field formed by the at least one target array element group can completely cover the region of interest in the target tissue;

controlling each array element in the at least one target array element group to emit ultrasonic waves to form the sound field, and receiving ultrasonic wave echoes fed back from the region of interest to obtain echo information of different positions in the region of interest;

generating an ultrasonic image according to the echo information;

12. An ultrasound imaging apparatus, comprising:

an ultrasonic probe;

a memory for storing a program;

a processor for executing a program in a memory to implement the method of any one of claims 1 to 11.

13. A computer-readable storage medium, characterized in that the medium has stored thereon a program which is executable by a processor to implement the method of any one of claims 1 to 11.