CN115381489A

CN115381489A - Method and device for measuring ultrasonic blood flow parameters and ocular vascular indexes

Info

Publication number: CN115381489A
Application number: CN202110567200.5A
Authority: CN
Inventors: 杜宜纲; 黄永; 林穆清; 杨雪梅
Original assignee: Shenzhen Mindray Bio Medical Electronics Co Ltd
Current assignee: Shenzhen Mindray Bio Medical Electronics Co Ltd
Priority date: 2021-05-24
Filing date: 2021-05-24
Publication date: 2022-11-25

Abstract

A method and a device for measuring ultrasonic blood flow parameters and ocular vascular indexes are provided, the method comprises the following steps: acquiring a first interest position and a second interest position on an ultrasonic image of a target blood vessel; determining a connecting line between the first interest position and the second interest position, wherein the connecting line comprises a plurality of divided intervals; for each interval, acquiring vector blood flow velocities at positions at two ends of the interval and interval length of the interval, and calculating a blood pressure difference between the positions at the two ends of the interval based on the vector blood flow velocities and the interval length; and displaying corresponding colors on different sections of the connecting line based on the magnitude of the blood pressure difference between the two end positions of each section so as to show the variation trend of the blood pressure difference between the first interested position and the second interested position. The local differential pressure calculation method and the local differential pressure calculation device can achieve accurate local differential pressure calculation.

Description

Method and device for measuring ultrasonic blood flow parameters and ocular vascular indexes

Technical Field

The application relates to the technical field of ultrasonic scanning, in particular to a method and a device for measuring blood flow parameters and ocular vascular indexes based on ultrasound.

Background

When a heart valve (including an aortic valve, a tricuspid valve, a mitral valve, a pulmonary valve and the like) is abnormal, the local blood pressure can be abnormally reduced after passing through the valve; arterial stenosis can cause a significant decrease in local blood pressure as blood flows through the stenosis; hypertension may be caused when baroreceptors of the carotid sinus and aortic arch become problematic; when the venous valve abnormally refluxes, the local blood pressure changes abnormally, so that blood refluxes and thrombus can be generated; excessive increase in intraocular pressure belongs to a more serious ocular disease, and studies show that retinal arteriosclerosis has a certain relationship with both blood pressure and intraocular pressure.

It follows that measurement of local blood pressure changes is of clinical value for diagnosis and study of many diseases. The needle can measure the intravascular pressure, but this is invasive. Common non-invasive methods are mainly intravascular pressure difference measurement methods based on Magnetic Resonance Imaging (MRI) or continuous doppler (CW). However, the MRI examination time is long, the cost is high, and CW lacks specific measurement position information. Therefore, in order to make accurate measurement of local blood pressure popular in clinical examinations, more advanced ultrasound measurement methods and techniques are also needed.

Disclosure of Invention

According to an aspect of the present application, there is provided a method of measuring an ultrasonic blood flow parameter, the method comprising: acquiring a first interest position and a second interest position on an ultrasonic image of a target blood vessel; determining a line between the first location of interest and the second location of interest, wherein the line comprises a plurality of partitioned intervals; for each interval, acquiring vector blood flow velocities at positions at two ends of the interval and an interval length of the interval, and calculating a blood pressure difference between the positions at the two ends of the interval based on the vector blood flow velocities and the interval length; displaying corresponding colors on different sections of the connecting line based on the magnitude of the blood pressure difference between the two end positions of each section so as to present the variation trend of the blood pressure difference between the first interest position and the second interest position.

According to another aspect of the present application, there is provided a method of measuring an ultrasonic blood flow parameter, the method comprising: acquiring a connecting line drawn on an ultrasonic image of a target blood vessel by a user, wherein the connecting line comprises a plurality of divided intervals; for each interval, acquiring vector blood flow velocities at positions at two ends of the interval and an interval length of the interval, and calculating a blood pressure difference between the positions at the two ends of the interval based on the vector blood flow velocities and the interval length; and displaying corresponding colors on different sections of the connecting line based on the magnitude of the blood pressure difference between the two end positions of each section so as to present the variation trend of the blood pressure difference on the connecting line.

According to yet another aspect of the present application, there is provided a method of measuring an ultrasonic blood flow parameter, the method comprising: transmitting ultrasonic waves to a target blood vessel along at least two different scanning angles, receiving echoes of the ultrasonic waves, and obtaining at least two groups of ultrasonic echo signals based on the echoes of the ultrasonic waves, wherein each group of ultrasonic echo signals is derived from the ultrasonic waves transmitted at one scanning angle; acquiring a first position of interest and a second position of interest on an ultrasound image of the target vessel, and a length between the first position of interest and the second position of interest; respectively obtaining at least two velocity components at the first interested position and at least two velocity components at the second interested position based on the at least two groups of ultrasonic echo signals, and synthesizing the at least two velocity components at each interested position to obtain a vector blood flow velocity at each interested position, wherein each velocity component is derived from one group of ultrasonic echo signals; calculating a blood pressure difference between the first location of interest and the second location of interest based on the vector blood flow velocity at the first location of interest, the vector blood flow velocity at the second location of interest, and the length between the first location of interest and the second location of interest.

According to still another aspect of the present application, there is provided a method of measuring an ocular vascular index, the method including: acquiring a blood pressure difference between a first interest position and a second interest position on an ultrasonic image of a target blood vessel, wherein the first interest position and the second interest position are respectively positioned in a common carotid artery and an internal carotid artery; obtaining blood flow parameters of an ocular vessel communicating with the internal carotid artery, the blood flow parameters including a peak systolic flow rate and an end diastolic flow rate; calculating a velocity difference between the peak systolic flow rate and the end diastolic flow rate, and calculating and outputting a ratio of the blood pressure difference to the velocity difference.

According to yet another aspect of the present application, there is provided an ultrasonic blood flow imaging apparatus comprising a transmitting circuit, a receiving circuit, an ultrasonic probe, a processor, and a display, wherein: the transmitting circuit is used for controlling the ultrasonic probe to transmit ultrasonic waves to a target part of a target object; the receiving circuit is used for controlling the ultrasonic probe to receive the echo of the ultrasonic wave and acquiring an ultrasonic echo signal from the echo of the ultrasonic wave; the processor is used for carrying out ultrasonic blood flow imaging based on the ultrasonic echo signal; the processor is also used for executing the ultrasonic blood flow parameter measuring method; the display is used for displaying the result output by the processor.

The method and the device for measuring the ultrasonic blood flow parameters and the ocular vascular indexes can realize accurate local pressure difference calculation, and are noninvasive and rapid; in addition, the method for measuring the ultrasonic blood flow parameters generates a pressure gradient map between two interested positions based on the vector blood flow velocities of a plurality of regions between the two interested positions on the target blood vessel ultrasonic image, so that the pressure difference change trend between the two interested positions can be visually presented, and the diagnosis of a doctor is better assisted; in addition, the method for measuring the ocular vascular index calculates parameters related to the ocular blood supply condition based on the pressure drop condition at the carotid sinus, and can provide clinical research and related guidance for ocular diseases, particularly ischemic ocular diseases for doctors.

Drawings

The above and other objects, features and advantages of the present application will become more apparent by describing in more detail embodiments of the present application with reference to the attached drawings. The accompanying drawings are included to provide a further understanding of the embodiments of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings, like reference numbers generally represent like parts or steps.

Fig. 1 shows a schematic flow diagram of a method of measuring an ultrasound blood flow parameter according to an embodiment of the present application.

Fig. 2 shows an exemplary schematic diagram of two locations of interest and a connection line between them in a method of measuring an ultrasound blood flow parameter according to an embodiment of the present application.

Fig. 3 shows an exemplary schematic diagram of two locations of interest and a connection line between them in a method of measuring an ultrasound blood flow parameter according to an embodiment of the present application.

Fig. 4 shows an exemplary schematic diagram of a variation trend of a blood pressure difference in a method of measuring an ultrasound blood flow parameter according to an embodiment of the present application.

Fig. 5 shows a schematic flow diagram of a method of measuring an ultrasound blood flow parameter according to another embodiment of the present application.

Fig. 6 shows a schematic flow diagram of a method of measuring an ultrasound blood flow parameter according to yet another embodiment of the present application.

Fig. 7 shows an exemplary schematic diagram of three locations of interest and the connecting lines between them in a method of measuring an ultrasound blood flow parameter according to yet another embodiment of the present application.

Fig. 8 shows a schematic flow diagram of a method of measuring an ultrasound blood flow parameter according to yet another embodiment of the present application.

Fig. 9 shows a schematic flow chart of a method of measuring an ocular vascular index according to yet another embodiment of the present application.

Fig. 10 shows exemplary diagrams of two locations of interest in a method of measuring ocular vascular index according to yet another embodiment of the present application.

Fig. 11 shows a schematic structural block diagram of an ultrasonic blood flow imaging apparatus according to an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, exemplary embodiments according to the present application will be described in detail below with reference to the accompanying drawings. It should be understood that the described embodiments are only some embodiments of the present application and not all embodiments of the present application, and that the present application is not limited by the example embodiments described herein. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the application described in the application without inventive step, shall fall within the scope of protection of the application.

First, a method of measuring an ultrasonic blood flow parameter according to an embodiment of the present application is described with reference to fig. 1. Fig. 1 shows a schematic flow diagram of a method 100 of measurement of ultrasound blood flow parameters according to an embodiment of the present application. As shown in fig. 1, the ultrasound blood flow parameter based measurement method 100 may include the steps of:

in step S110, a first location of interest and a second location of interest on an ultrasound image of a target vessel are acquired.

In an embodiment of the present application, the target vessel may be first ultrasonically imaged to obtain an ultrasound image of the target vessel, which is displayed to the user, and the user determines two locations of interest (e.g., via a user interface) from the ultrasound image where the differential pressure measurement is to be taken, namely a first location of interest and a second location of interest. Therefore, according to the user operation, the first interesting position and the second interesting position selected by the user can be obtained. In other examples, the two locations of interest may also be automatically selected by the ultrasound system in some cases, for example, by detecting that the system finds a possible problem somewhere in the blood vessel, the location at which the blood pressure difference is to be measured may be automatically determined.

Fig. 2 and 3 show two examples of two locations of interest within a blood vessel, respectively. Where fig. 2 shows a schematic view of a bifurcated vessel, such as a carotid bifurcation, two locations of interest, a first location of interest a and a second location of interest B as shown in fig. 2, may be determined automatically or manually by a user when it is desired to measure the blood pressure difference from the common carotid artery to the internal carotid artery. Fig. 3 shows a schematic view of a blood vessel with plaque, and when the system detects the plaque in a certain position of the blood vessel, the system can automatically determine the interested positions on two sides of the plaque, such as a first interested position A and a second interested position B shown in fig. 3, so as to measure the pressure drop of the blood after passing through the plaque. Of course, the two locations of interest shown in FIG. 3 may also be determined by the user.

In step S120, a connecting line between the first interest location and the second interest location is determined, wherein the connecting line includes a plurality of divided intervals.

In an embodiment of the present application, after the first interesting position and the second interesting position are obtained, a connection line between the first interesting position and the second interesting position may be determined, where the connection line is a continuous connection line respectively connected to the first interesting position and the second interesting position, and the connection line is divided into a plurality of intervals. The connecting line may be a straight line, a broken line, a curved line, or an irregularly shaped line, and is not particularly limited herein. The connecting line may be in the form of a line or a strip, that is, may have a certain thickness. In the embodiment of the present application, the dividing of the connecting line between the two interested locations into a plurality of intervals is to perform blood pressure difference calculation for each interval to obtain the trend of pressure difference change between the two interested locations, so as to more accurately realize the measurement of local blood pressure change, as will be described in steps S130 to S140 below.

Illustratively, a line between the first and second locations of interest (such as a line between the first and second locations of interest a and B as shown in fig. 2 and 3) may be divided into a plurality of line segments as a plurality of intervals (such as a line between the first and second locations of interest a and B as shown in fig. 4 divided into equally or unequally spaced segments). In one example, a line between the first and second locations of interest may be automatically generated from a trend of a blood vessel in which the first and second locations of interest are located such that the line approximately coincides with an axis of the blood vessel. In particular, points on the line are approximately equidistant from the anterior and posterior walls of the vessel, such that the line is approximately in the middle region of the vessel. The blood flow generally flows along the trend direction of the blood vessel, the general blood flow flowing path can be drawn by the method, particularly, the blood flow trend can be presented well for the blood vessel at the bifurcation, and the doctor can conveniently and quickly know the blood flow state of the local blood vessel by calculating the blood pressure difference of each section on the connecting line. In another example, a line between the first and second locations of interest may be generated from a blood flow path of a blood vessel in which the first and second locations of interest are located, such that the generated line is closer to a true flow path of the blood flow. Specifically, the blood flow path may be determined according to the vector blood flow velocity of the blood vessel in which the first interest position and the second interest position are located, for example, taking the blood inflow position (the first interest position or the second interest position) as a starting point, taking neighboring points based on the direction of the vector blood flow velocity of the starting point, continuing to find neighboring points based on the direction of the vector blood flow velocity of the neighboring points, and finally fitting the points to the connection line. The real flow direction of the blood flow can be accurately identified through the method, so that the flow path of the blood flow can be accurately described, more accurate positioning is provided for subsequent measurement of the blood pressure difference, and more accurate measurement indexes are provided for a doctor to judge the blood flow state of a local blood vessel. In another example, a line between the first location of interest and the second location of interest may be traced manually by the user, for example, by tracing the line on the ultrasound image through a user interaction interface.

In step S130, for each of the sections, a vector blood flow velocity at both end positions of the section and a section length of the section are acquired, and a blood pressure difference between both end positions of the section is calculated based on the vector blood flow velocity and the section length.

In an embodiment of the present application, for each interval into which a connection line between the first interest location and the second interest location is divided, a vector blood flow velocity at positions at both ends of the interval and a length of the interval may be acquired to calculate a blood pressure difference between the positions at both ends of the interval. By performing such calculation for each interval, the blood pressure difference between the two end positions of each interval can be obtained, and thus the pressure difference variation between the first interest position and the second interest position can be obtained. For example, for a connection line between the first interest location and the second interest location, the connection line may be automatically or manually divided into a plurality of line segments by a user, and for each line segment, the vector blood flow velocity between the end points at both ends of the line segment and the length of the line segment are calculated to calculate the blood pressure difference between the end points at both ends of the line segment, so as to obtain the pressure difference variation between the first interest location and the second interest location. Described with the example shown in fig. 4, the pressure differential change between the first location of interest a and the second location of interest B can be calculated by the following equation (1):

where i and j are two end points of any one section on a connecting line between the first interesting position a and the second interesting position B (e.g., the positions of two adjacent points on the connecting line between the first interesting position a and the second interesting position B), Δ p _ij Is the difference in blood pressure between the two endpoints i and j of the interval, v _i And v _j The vector blood flow velocity l at two end points i and j of the interval _ij For the length of this interval, ρ is the blood density (blood viscosity) and t is the time variable. When the pressure difference between two points of interest is calculated based on the formula (1), the influence of the blood viscosity is not ignored, and the velocity change between the points AB and AB is not ignored, and the most accurate calculation result of the local pressure difference can be obtained with respect to the calculation methods described in the later embodiments, such as the formula (3) and the formula (5). When the pressure difference between two interested positions is calculated based on the formula (1), the velocity of a plurality of points between the two interested positions is required to be integrated, and the accurate pressure difference calculation mode can be met only by the vector blood flow imaging technology. Therefore, the measurement method 100 based on ultrasonic blood flow imaging according to the embodiment of the present application calculates the local blood vessel pressure difference based on the vector blood flow velocity, can realize accurate local pressure difference calculation, and is noninvasive and fast.

In the embodiment of the present application, the vector blood flow velocity at the two end positions of each interval may be calculated by a speckle tracking method, a transverse wave oscillation method, or a multi-angle deflection transmitting and/or receiving method based on the doppler principle. The vector blood flow velocity may include velocity magnitude, and may also include velocity magnitude and direction.

Taking the example of obtaining the vector blood flow velocity by the multi-angle deflection transmitting/receiving method, the ultrasonic probe transmits ultrasonic waves to a target blood flow region along a first scanning angle, and receives ultrasonic echoes of the ultrasonic waves returned from the target blood flow region. Based on the ultrasonic echo, a first ultrasonic echo signal along the first scanning angle is obtained, and according to the first ultrasonic echo signal, a first blood flow velocity of a target position (also called target point) in the target blood flow region is obtained, wherein the first blood flow velocity is actually a projection component (also called velocity component) of a vector blood flow velocity of the target position on the first scanning angle. Similarly, by emitting ultrasound waves to the target blood flow region along a second scanning angle by the ultrasound probe, a second blood flow velocity of the target position can be obtained, and the second blood flow velocity is actually a projection component (also referred to as a velocity component) of the vector blood flow velocity of the target position on the second scanning angle. And carrying out angle synthesis on the first blood flow velocity and the second blood flow velocity to obtain the actual velocity magnitude and direction, namely the vector blood flow velocity.

As an example, the vector blood flow velocity may be obtained by a vector blood flow imaging method based on speckle tracking. Wherein vector blood flow velocity calculation for speckle tracking can be achieved using sum of absolute differences. The vector blood flow velocity with higher precision can be obtained based on a plane wave emission and spot tracking method.

As an example, the vector blood flow velocity may be obtained by a vector blood flow imaging method based on a transverse wave oscillation method. The method comprises the steps of obtaining longitudinal speed through a traditional calculation method based on a Doppler principle, obtaining transverse speed through an ultrasonic sound field generating transverse oscillation and calculating based on an autocorrelation method, and then combining the transverse speed and the longitudinal speed to obtain vector blood flow speed.

The vector blood flow velocity is the actual velocity of the blood flow (such as red blood cells in the blood flow), or is closer to the actual velocity of the blood flow (such as red blood cells in the blood flow); the velocity direction is the actual flow direction of the blood flow (e.g., red blood cells in the blood flow), or is closer to the actual flow direction of the blood flow (e.g., red blood cells in the blood flow); the direction of the vector blood flow velocity may be in the interval 0 ° to 360 ° in the imaging plane, which direction may characterize the actual flow direction of the blood flow.

Based on the vector blood flow velocities at the two end positions of each interval, a pressure gradient map between the first and second locations of interest may be generated to present a trend of change in the blood pressure difference between the first and second locations of interest, as will be described in step S140.

In step S140, displaying corresponding colors on different sections of the link based on the magnitude of the blood pressure difference between the two end positions of each of the sections to present the trend of the blood pressure difference between the first and second interest positions.

In an embodiment of the present application, after calculating the blood pressure difference between two end positions of each section of the connecting line between the first interest position and the second interest position, the blood pressure difference between two end positions of each section may be calculated in corresponding colors on different sections of the connecting line to generate a pressure gradient map reflecting the pressure drop variation trend between the first interest position and the second interest position, for example, as shown in fig. 4. In fig. 4, different intervals of different pressure drop values are presented in different colors. It should be noted here that the drawings in the patent application are not limited to color drawings, and fig. 4 shows a gray scale image, and in practical application, the color map in fig. 4 may be a color map to more clearly show the pressure drop trend between two interested positions. In the example shown in fig. 4, the trend of the pressure difference between the first interest position a and the second interest position B is displayed in different colors in each section of the connecting line between the first interest position a and the second interest position B, and the display mode is more capable of clearly and correspondingly displaying the pressure drop condition of each section. Furthermore, when the blood pressure difference of a certain section on the connecting line is larger than a preset threshold value, the blood flow corresponding to the certain section is prompted to be abnormal. For example, different colors represent different pressure difference sizes, green indicates that the blood pressure difference corresponding to the interval is small, blood flow is smooth, no obvious block or plaque exists, red indicates that the blood pressure difference corresponding to the interval is large, plaque may exist at the position, and a doctor can quickly identify the state of the blood vessel through color prompt, accurately position an abnormal position, and improve diagnosis efficiency. In other examples, the pressure gradient between two locations of interest may be plotted in other ways, such as in the form of a line plotting different pressure drops across different intervals.

In further embodiments of the present application, the method 100 may further comprise (not shown): in response to a selection operation of a blood pressure difference between both end positions of a certain section on the link, a corresponding blood pressure difference value is displayed. In the embodiment, the pressure gradient map can realize user interaction, and the blood pressure difference value between two end positions of any interval on a connecting line between two interested positions can be further presented through user selection, so that the user can know the pressure drop trend between the two interested positions, and simultaneously can obtain the pressure drop quantitative value result of any interval, and the diagnosis of a doctor is facilitated.

Generally, the method 100 for measuring ultrasonic blood flow parameters according to the embodiment of the present application calculates local blood vessel pressure difference based on vector blood flow velocity, can realize accurate local pressure difference calculation, and is noninvasive and fast; in addition, the method for measuring the ultrasonic blood flow parameters according to the embodiment of the application generates a pressure gradient map between two interested positions based on the vector blood flow velocities of a plurality of areas between the two interested positions on the target blood vessel ultrasonic image, the visual presentation of the pressure difference variation trend between the two interested positions can be realized, the abnormal position can be accurately positioned through different colors, and a doctor is prompted to pay attention to the abnormal position, so that the diagnosis of the doctor can be better assisted.

The above exemplarily illustrates a method for measuring an ultrasound blood flow parameter according to an embodiment of the present application. Methods of measuring ultrasonic blood flow parameters according to other embodiments of the present application are described below with reference to fig. 5 to 10.

Fig. 5 shows a schematic flow diagram of a method 500 of measuring an ultrasound blood flow parameter according to another embodiment of the present application. As shown in fig. 5, the method 500 for measuring ultrasound blood flow parameters may include the following steps:

in step S510, a first location of interest and a second location of interest on an ultrasound image of a target vessel are acquired.

In step S520, a connecting line between the first interest location and the second interest location is determined, wherein the connecting line includes a plurality of divided intervals.

In step S530, for each of the sections, the blood flow velocities at the both end positions of the section are acquired, and the blood pressure difference between the both end positions of the section is calculated based on the blood flow velocities.

In step S540, displaying corresponding colors on different sections of the link based on the magnitude of the blood pressure difference between the two end positions of each section to present the trend of the blood pressure difference between the first and second interest positions.

In an embodiment of the present application, the method 500 for measuring ultrasound blood flow parameters is partially similar to and partially different from the method 100 for measuring ultrasound blood flow parameters described above. Specifically, steps S510, S520, and S540 are the same as steps S110, S120, and S140, respectively, with some differences between step S530 and step S130. For the sake of brevity, the same parts between the method 500 for measuring ultrasound blood flow parameters herein and the method 100 for measuring ultrasound blood flow parameters described previously will not be described in detail, and only the different parts of both will be described.

In the embodiment of the present application, after determining the connection line between the first interest position and the second interest position and the plurality of intervals thereof, the method 100 for measuring an ultrasound blood flow parameter calculates the blood pressure difference between the two end positions of each interval based on the vector blood flow velocity and the interval length at the two end positions of each interval in step S130, and after determining the connection line between the first interest position and the second interest position and the plurality of intervals thereof, the method 500 for measuring an ultrasound blood flow parameter calculates the blood pressure difference between the two end positions of each interval based on the blood flow velocity at the two end positions of each interval (the blood flow velocity is not limited to the vector blood flow velocity or the blood flow velocity measured based on the pulse doppler, and the interval length does not need to be determined) in step S530. Described with the example shown in fig. 4, the blood pressure difference of any interval between the first position of interest a and the second position of interest B can be calculated by the following formula (2):

where i and j are two end points of any one section on a connecting line between the first interesting position A and the second interesting position B (e.g. positions of two adjacent points on the connecting line between the first interesting position A and the second interesting position B), Δ p _ij Is the blood pressure difference between the two endpoints i and j of the interval, v _i And v _j The blood flow velocities at the two endpoints i and j of the interval are respectively.

The blood pressure difference calculated based on the above formula ignores the influence of the blood viscosity, and the blood viscosity is assumed to be constant. Because, for blood, changes in blood flow velocity, while resulting in changes in blood viscosity, are relatively small and can be ignored. Such a calculation may be somewhat less accurate than the calculation in equation (1), but is simpler.

In an embodiment of the present application, the blood flow velocity acquired in step S530 may include a vector blood flow velocity or a blood flow velocity measured based on multi-point pulse doppler. The vector blood flow velocity may be calculated by a speckle tracking method, a transverse wave oscillation method, or a multi-angle deflection transmitting and/or receiving method based on the doppler principle, which is similar to the foregoing description and is not repeated here. Finally, a pressure gradient map between the first and second locations of interest may be generated based on the blood flow velocity at the two end positions of each interval.

Based on the above description, the method 500 for measuring an ultrasonic blood flow parameter according to the embodiment of the present application generates a pressure gradient map between two interested locations based on blood flow velocities at multiple locations in an area between the two interested locations on an ultrasonic image of a target blood vessel, and can achieve an intuitive presentation of a pressure difference variation trend between the two interested locations, thereby better assisting a doctor in diagnosis.

Fig. 6 shows a schematic flow diagram of a method 600 of measuring an ultrasound blood flow parameter according to yet another embodiment of the present application. As shown in fig. 6, the method 600 for measuring ultrasound blood flow parameters may include the following steps:

in step S610, ultrasound waves are transmitted to a target blood vessel along at least two different scanning angles, echoes of the ultrasound waves are received, and at least two sets of ultrasound echo signals are obtained based on the echoes of the ultrasound waves, wherein each set of ultrasound echo signals is derived from the ultrasound waves transmitted at one scanning angle.

In step S620, a first location of interest and a second location of interest on an ultrasound image of the target vessel and a length between the first location of interest and the second location of interest are acquired.

At step S630, at least two velocity components at the first location of interest and at least two velocity components at the second location of interest are obtained based on the at least two sets of ultrasound echo signals, respectively, and the at least two velocity components at each location of interest are synthesized to obtain a vector blood flow velocity at each location of interest, wherein each velocity component is derived from one set of ultrasound echo signals.

In step S640, a blood pressure difference between the first and second locations of interest is calculated based on the vector blood flow velocity at the first location of interest, the vector blood flow velocity at the second location of interest, and the length between the first and second locations of interest.

In the embodiment of the present application, the method 600 for measuring ultrasound blood flow parameters obtains the respective vector blood flow velocities of the first interested position and the second interested position on the ultrasound image of the target blood vessel by the multi-angle deflection transmitting/receiving method. The following description is given by way of example along two scan angles. Ultrasonic waves are transmitted to a target blood flow region along a first scanning angle by an ultrasonic probe, and ultrasonic echoes of the ultrasonic waves returned from the target blood flow region are received. Based on the ultrasound echoes, a first ultrasound echo signal along the first scan angle is obtained, and from the first ultrasound echo signal, a first blood flow velocity of a target location (including a first location of interest and a second location of interest in the present embodiment) within the target blood flow region is obtained, the first blood flow velocity being in fact a projection component (also referred to as a velocity component) of a vector blood flow velocity of the target location at the first scan angle. Similarly, a second blood flow velocity at the target position can be obtained by the ultrasound probe emitting ultrasound waves to the target blood flow region along a second scanning angle, and the second blood flow velocity is actually a projection component (also referred to as a velocity component) of the vector blood flow velocity at the target position on the second scanning angle. And carrying out angle synthesis on the first blood flow velocity and the second blood flow velocity to obtain the actual velocity magnitude and direction, namely the vector blood flow velocity. In the above manner, the vector blood flow velocity at the first location of interest and the vector blood flow velocity at the second location of interest may be obtained separately.

Based on the respective vector blood flow velocities of the first and second locations of interest and the length between these two locations, a blood pressure difference between the first and second locations of interest may be calculated. Similarly as described in the previous embodiments, a connecting line between the first interesting position and the second interesting position can be automatically generated according to the trend of the blood vessel in which the first interesting position and the second interesting position are located, and the length between the first interesting position and the second interesting position can be determined based on the connecting line; or generating a connecting line between the first interest position and the second interest position according to the blood flow path of the blood vessel in which the first interest position and the second interest position are positioned, and determining the length between the first interest position and the second interest position based on the connecting line; still alternatively, a connecting line drawn by the user between the first interest position and the second interest position is acquired, and the length between the first interest position and the second interest position is determined based on the connecting line. Described with the example shown in fig. 2, the blood pressure difference between the first location of interest a and the second location of interest B may be calculated by the following equation (3):

wherein, Δ p _AB Is the blood pressure difference, v, between a first location of interest A and a second location of interest B _A And v _B Vector blood flow velocities, l, for the first A and second B location of interest, respectively _AB P is the blood density and t is the time variable, being the length between the first and second location of interest.

Therefore, the method 600 for measuring ultrasound blood flow parameters according to the embodiment of the present application calculates vector blood flow velocities of two interested positions of an ultrasound image of a target blood vessel based on a multi-angle deflection transmitting and/or receiving method of the doppler principle, and calculates a blood pressure difference between the two interested positions based on the vector blood flow velocities between the two interested positions, so as to achieve accurate local pressure difference calculation, and be noninvasive and fast.

In a further embodiment of the present application, the method 600 of measuring an ultrasound blood flow parameter may further comprise the steps of (not shown): acquiring a third location of interest on an ultrasound image of the target vessel and a length between the first location of interest and the third location of interest; obtaining a vector blood flow velocity at the third location of interest based on the at least two sets of ultrasound echo signals; calculating a blood pressure difference between the first location of interest and the third location of interest as a second blood pressure difference based on the vector blood flow velocity at the first location of interest, the vector blood flow velocity at the third location of interest, and the length between the first location of interest and the third location of interest; calculating and outputting a difference between the first blood pressure difference and the second blood pressure difference, taking a blood pressure difference between the first interest location and the second interest location as a first blood pressure difference.

In this embodiment, a third location of interest on the ultrasound image of the target vessel is also obtained, as described below in connection with FIG. 7. As shown in fig. 7, a first location of interest a, a second location of interest B, and a third location of interest C are included on the ultrasound image of the target vessel. Wherein the blood pressure difference between the first location of interest a and the second location of interest B can be calculated as a first blood pressure difference in the manner described above (as shown in equation (3) above), and the blood pressure difference between the first location of interest a and the third location of interest C can be calculated as a second blood pressure difference in the same manner, as shown in equation (4) below:

wherein, Δ p _AC Is the blood pressure difference, v, between the first location of interest A and the third location of interest C _A And v _C Vector blood flow velocities, l, for the first A and third C location of interest, respectively _AC P is the blood density and t is the time variable, being the length between the first and third location of interest.

In the example shown in fig. 7, a schematic diagram of a bifurcated vessel is shown, such as a carotid bifurcation, where the first location of interest a is in the common carotid artery, the second location of interest B is in the internal carotid artery, and the third location of interest C is in the external carotid artery, therefore, the difference between the blood pressure difference between AB and the blood pressure difference between AC can provide more reference data for the physician, so that the physician knows the pressure drop contrast in the bifurcated vessel.

Fig. 8 shows a schematic flow diagram of a method 800 of measuring an ultrasound blood flow parameter according to yet another embodiment of the present application. As shown in fig. 8, the method 800 for measuring ultrasound blood flow parameters may include the following steps:

in step S810, ultrasound waves are transmitted to a target blood vessel along at least two different scanning angles, echoes of the ultrasound waves are received, and at least two sets of ultrasound echo signals are obtained based on the echoes of the ultrasound waves, wherein each set of ultrasound echo signals is derived from the ultrasound waves transmitted at one scanning angle.

In step S820, a first location of interest and a second location of interest on an ultrasound image of the target vessel are acquired.

In step S830, at least two velocity components at each of the interested locations are obtained based on the at least two sets of ultrasound echo signals, respectively, and the at least two velocity components at each of the interested locations are synthesized to obtain a vector blood flow velocity at each of the interested locations, wherein each velocity component is derived from a set of ultrasound echo signals.

In step S840, a blood pressure difference between the first location of interest and the second location of interest is calculated based on the vector blood flow velocity at the first location of interest and the vector blood flow velocity at the second location of interest.

In an embodiment of the present application, the method 800 of measuring an ultrasound blood flow parameter is partially similar and partially different from the method 600 of measuring an ultrasound blood flow parameter described above. Specifically, steps S810 and S830 are respectively different from steps S610 and S630, step S820 is different from step S620, and step S840 is different from step S640. For the sake of brevity, the same parts between the method 800 for measuring ultrasound blood flow parameters herein and the method 600 for measuring ultrasound blood flow parameters described previously will not be described in detail, and only the different parts of both will be described.

In the embodiment of the present application, after the step S620 acquires the first and second interest locations, the method 600 for measuring ultrasound blood flow parameters further needs to acquire the length between the first and second interest locations, and after the step S640 acquires the first and second interest locations, the method 800 for measuring ultrasound blood flow parameters calculates the blood pressure difference between the two interest locations based on the respective vector blood flow velocities at the two interest locations and the length between the two interest locations, and after the step S820 acquires the first and second interest locations, the method 800 for measuring ultrasound blood flow parameters calculates the blood pressure difference between the two interest locations based on the respective vector blood flow velocities at the two interest locations without acquiring the length between the first and second interest locations. Described with the example of fig. 2, the blood pressure difference between the first location of interest a and the second location of interest B may be calculated by the following equation (5):

wherein, Δ p _AB Is the blood pressure difference, v, between a first location of interest A and a second location of interest B _A And v _B The vector blood flow velocities of the first and second locations of interest a and B, respectively.

The blood pressure difference calculated based on the above formula ignores the influence of the blood viscosity, and the blood viscosity is assumed to be constant. Because, for blood, changes in blood flow velocity, while resulting in changes in blood viscosity, are relatively small and negligible. Such a calculation may be somewhat less accurate than the calculation in equation (3), but is simpler. Further, the blood pressure difference calculated based on the above formula ignores the blood flow velocity change between the two points AB, and therefore, there may be a little error with respect to the calculation method in formula (1), but it is simpler. When the pressure difference is calculated based on the formula (5), the blood flow velocities of two positions need to be measured simultaneously, the traditional pulse Doppler cannot be realized, and the blood flow velocities of different positions can be measured simultaneously only by adopting a multi-point pulse Doppler or vector blood flow imaging technology.

Based on the above description, the method 800 for measuring ultrasound blood flow parameters according to the embodiment of the present application calculates the respective vector blood flow velocities of two interested positions of an ultrasound image of a target blood vessel based on the multi-angle deflection transmitting and/or receiving method of the doppler principle, and calculates the blood pressure difference between the two interested positions based on the vector blood flow velocities between the two interested positions, so that accurate local pressure difference calculation can be realized, and is noninvasive and fast.

In a further embodiment of the present application, the method 800 of measuring an ultrasound blood flow parameter may further comprise the steps of (not shown): acquiring a third interest position on the ultrasonic image of the target blood vessel; obtaining a vector blood flow velocity at the third location of interest based on the at least two sets of ultrasound echo signals; calculating a blood pressure difference between the first location of interest and the third location of interest as a second blood pressure difference based on the vector blood flow velocity at the first location of interest and the vector blood flow velocity at the third location of interest; calculating and outputting a difference between the first blood pressure difference and the second blood pressure difference, taking a blood pressure difference between the first interest location and the second interest location as a first blood pressure difference.

In this embodiment, a third location of interest on the ultrasound image of the target vessel is also obtained, may still be described in connection with fig. 7. As shown in fig. 7, a first location of interest a, a second location of interest B, and a third location of interest C are included on the ultrasound image of the target vessel. Wherein the blood pressure difference between the first location of interest a and the second location of interest B can be calculated as a first blood pressure difference in the manner described above (as shown in equation (5) above), and the blood pressure difference between the first location of interest a and the third location of interest C can be calculated as a second blood pressure difference in the same manner, as shown in equation (6) below:

wherein, Δ p _AC Is the blood pressure difference, v, between the first location of interest A and the third location of interest C _A And v _C The vector blood flow velocities of the first and third locations of interest a and C, respectively.

In the example shown in fig. 7, a schematic view of a bifurcated vessel is shown, such as a carotid bifurcation, where the first location of interest a is in the common carotid artery, the second location of interest B is in the internal carotid artery, and the third location of interest C is in the external carotid artery, and therefore the difference between the blood pressure difference between AB and the blood pressure difference between AC can provide more reference data to the physician, so that the physician knows the pressure drop contrast in the bifurcated vessel.

FIG. 9 shows a schematic flow diagram of a method 900 for measuring ocular vascular index, in accordance with one embodiment of the present application. As shown in fig. 9, the method 900 for measuring ocular vascular index may include the steps of:

in step S910, a blood pressure difference between a first interest location and a second interest location on an ultrasound image of a target vessel is acquired, wherein the first interest location and the second interest location are located in a common carotid artery and an internal carotid artery, respectively.

In step S920, blood flow parameters of an ocular vessel communicating with the internal carotid artery are acquired, wherein the blood flow parameters include a peak systolic flow rate and an end diastolic flow rate.

In step S930, a velocity difference between the peak systolic flow rate and the end diastolic flow rate is calculated, and a ratio of the blood pressure difference to the velocity difference is calculated and output.

In the embodiment of the present application, the method 900 for measuring an ocular vascular index, which is combined with the internal carotid differential pressure to calculate the ocular vascular index, can provide a doctor with clinical research and related diagnosis of ocular diseases, especially ischemic ocular diseases, which will be described in detail later. Wherein the internal carotid differential pressure refers to the differential pressure between the inside of the common carotid artery and the inside of the internal carotid artery, the first and second locations of interest are thus obtained inside the common carotid artery and the internal carotid artery, respectively, and the calculation of the blood pressure difference between the first and second locations of interest can be as described in the previous embodiments.

In one embodiment, acquiring a blood pressure difference between the first interest position and the second interest position on the ultrasound image of the target blood vessel in step S910 may include: acquiring respective vector blood flow velocities at a first and a second location of interest on an ultrasound image of the target vessel, and a length between the first and second location of interest; calculating the blood pressure difference between the first and second locations of interest based on the vector blood flow velocity at the first location of interest, the vector blood flow velocity at the second location of interest, and the length between the first and second locations of interest, as shown in equation (3) above.

In another embodiment, the obtaining a blood pressure difference between the first interest position and the second interest position on the ultrasound image of the target blood vessel in step S910 may include: acquiring respective blood flow velocities of a first interest position and a second interest position on an ultrasonic image of the target blood vessel; calculating the blood pressure difference between the first and second locations of interest based on the blood flow velocity at the first and second locations of interest, as shown in equation (5) above.

In still another embodiment, the obtaining a blood pressure difference between the first interest position and the second interest position on the ultrasound image of the target blood vessel in step S910 may include: acquiring a blood flow velocity at a maximum stenosis of an internal carotid artery between a first interest position and a second interest position on an ultrasound image of the target vessel; calculating the blood pressure difference between the first and second locations of interest based on the blood flow velocity at the maximum stenosis of the internal carotid artery, which may be calculated as shown in equation (7):

where Δ p is the blood pressure difference between the first and second location of interest, v _max Is the blood flow velocity at the maximum narrowing of the internal carotid artery between the first and second locations of interest. The blood pressure difference calculated based on equation (7) ignores the effect of blood viscosity, assumes the blood viscosity as a constant, and also ignores the blood flow velocity change between the two locations of interest, based on the pressure difference measured by a certain assumption that the blood flow velocity at the stenosis of the vessel is much greater than that of the normal vessel. Such a calculation the accuracy of the above described calculation may be somewhat reduced, but it is simpler because only the maximum blood flow velocity has to be measured, which can be achieved by conventional pulse doppler.

Thus, in embodiments of the present application, the measurement method 900 based on ultrasound blood flow imaging may calculate the internal carotid artery pressure difference based on blood flow velocity measured by a conventional pulse doppler method, blood flow velocity measured by multi-point pulse doppler, or vector blood flow velocity (wherein the vector blood flow velocity is calculated by a speckle tracking method, a transverse wave oscillation method, or a multi-angle deflection transmitting and/or receiving method based on the doppler principle). Since the ophthalmic artery is a branch of the internal carotid artery, the blood supply to the distal ophthalmic artery may be affected when there is a large pressure drop in the carotid sinus, especially in the case of a large pressure difference from the common carotid artery to the internal carotid artery. Therefore, the method 900 for measuring the ocular vascular index can calculate a parameter related to the ocular blood supply condition based on the pressure drop condition at the carotid sinus. Described below in conjunction with fig. 10.

As shown in fig. 10, a carotid bifurcated vessel is shown with a first site of interest a in the common carotid artery and a second site of interest B in the internal carotid artery with a stenosis or plaque in the neck, the internal carotid artery in communication with the ophthalmic artery. The line AB crosses the internal carotid plaque, or crosses the internal carotid stenosis, and the pressure drop Δ p between AB is then obtained. Then, by measuring the blood flow velocity of the ocular vessels by means of ultrasound, such as based on a pulse doppler method, blood flow parameters of at least one of the ocular artery, the central retinal artery, the ciliary artery can be obtained, the blood flow parameters including peak systolic flow velocity (PSV) and end diastolic flow velocity (EDV). The new parameters can be calculated by the following equation (8):

wherein a higher Q value indicates a greater likelihood of ischemia in the ocular vessel and/or a greater correlation between the cause of ischemia and carotid stenosis. A lower Q value indicates a lower probability of ischemia in the ocular vessel or a lower influence of carotid stenosis.

In a further embodiment of the present application, the method 900 for measuring an ocular vascular index may further include the following steps (not shown): comparing the ratio (namely the Q value) with a preset threshold value, and outputting prompt information according to the comparison result; when the ratio is greater than a preset threshold, the prompt message includes: the ocular vessels are highly likely to have ischemia, and/or the cause of ischemia is highly correlated with carotid stenosis; when the ratio is smaller than a preset threshold, the prompt message includes: the ocular vessels are less likely to have ischemia, or the cause of ischemia is less associated with carotid stenosis.

Therefore, the method 900 for measuring the ocular vascular index according to the embodiment of the present application calculates a parameter related to the blood supply condition of the eye based on the pressure drop condition at the carotid sinus, and can provide a doctor with clinical research and related diagnosis of ocular diseases, especially ischemic ocular diseases.

The measurement methods of the ultrasonic blood flow parameters and the ocular vascular index according to the embodiments of the present application are exemplarily shown above. An ultrasonic blood flow imaging apparatus provided according to another aspect of the present application is described below in conjunction with fig. 11. Fig. 11 shows a schematic block diagram of an ultrasonic blood flow imaging apparatus 1100 according to an embodiment of the present application. As shown in fig. 11, the ultrasonic blood flow imaging apparatus 1100 includes a transmitting circuit 1120, a receiving circuit 1130, an ultrasonic probe 1110, a processor 1140, and a display 1150, wherein: the transmitting circuit 1120 is configured to control the ultrasound probe 1110 to transmit an ultrasound wave to a target portion of a target object; the receiving circuit 1130 is configured to control the ultrasonic probe 1110 to receive the echo of the ultrasonic wave, and acquire an ultrasonic echo signal from the echo of the ultrasonic wave; the processor 1140 is configured to perform ultrasonic blood flow imaging based on the ultrasonic echo signals, and is further configured to perform the aforementioned measurement method of the ultrasonic blood flow parameter or the ocular vascular index according to the embodiment of the present application; display 1150 is used to display the results output by processor 1140. The structure and operation of the ultrasonic blood flow imaging apparatus 1100 according to the embodiment of the present application can be understood by those skilled in the art with reference to the foregoing description of the method for measuring the ultrasonic blood flow parameter or the ocular vascular index according to the embodiment of the present application, and for brevity, detailed description of the detailed operations of the components of the ultrasonic blood flow imaging apparatus 1100 is omitted here.

Based on the above description, the method for measuring the ultrasonic blood flow parameters and the ocular vascular index and the ultrasonic blood flow imaging device according to the embodiment of the present application calculate the local vascular pressure difference based on the vector blood flow velocity, can realize accurate local pressure difference calculation, and are noninvasive and fast; in addition, the method for measuring the ultrasonic blood flow parameters generates a pressure gradient map between two interested positions based on the vector blood flow velocities of a plurality of regions between the two interested positions on the target blood vessel ultrasonic image, so that the pressure difference change trend between the two interested positions can be visually presented, and the diagnosis of a doctor is better assisted; in addition, the measuring method based on the ocular vascular index calculates a parameter related to the blood supply condition of the eye based on the pressure drop condition at the carotid sinus, and can provide clinical research and related diagnosis of ocular diseases, particularly ischemic ocular diseases for doctors.

Although the example embodiments have been described herein with reference to the accompanying drawings, it is to be understood that the above-described example embodiments are merely illustrative and are not intended to limit the scope of the present application thereto. Various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the scope or spirit of the present application. All such changes and modifications are intended to be included within the scope of the present application as claimed in the appended claims.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the technical solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described device embodiments are merely illustrative, and for example, the division of the units is only one logical functional division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another device, or some features may be omitted, or not executed.

In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the application may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

Similarly, it should be appreciated that in the description of exemplary embodiments of the present application, various features of the present application are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the application and aiding in the understanding of one or more of the various inventive aspects. However, the method of this application should not be construed to reflect the intent: this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this application.

It will be understood by those skilled in the art that all of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the processes or elements of any method or apparatus so disclosed, may be combined in any combination, except combinations where such features are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.

Furthermore, those skilled in the art will appreciate that while some embodiments described herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the application and form different embodiments. For example, in the claims, any of the claimed embodiments may be used in any combination.

The various component embodiments of the present application may be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. It will be appreciated by those skilled in the art that a microprocessor or Digital Signal Processor (DSP) may be used in practice to implement some or all of the functionality of some of the modules in an item analysis apparatus according to embodiments of the present application. The present application may also be embodied as ultrasound blood flow imaging apparatus programs (e.g., computer programs and computer program products) for performing a portion or all of the methods described herein. Such programs implementing the present application may be stored on a computer readable medium or may be in the form of one or more signals. Such a signal may be downloaded from an internet website or provided on a carrier signal or in any other form.

It should be noted that the above-mentioned embodiments illustrate rather than limit the application, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The application may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several ultrasonic blood flow imaging means, several of these ultrasonic blood flow imaging means may be embodied by one and the same item of hardware. The usage of the words first, second and third, etcetera do not indicate any ordering. These words may be interpreted as names.

The above description is only for the specific embodiments of the present application or the description thereof, and the protection scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope disclosed in the present application, and shall be covered by the protection scope of the present application. The protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method of measuring an ultrasonic blood flow parameter, the method comprising:

acquiring a first interest position and a second interest position on an ultrasonic image of a target blood vessel;

determining a line between the first location of interest and the second location of interest, wherein the line comprises a plurality of divided intervals;

for each interval, acquiring vector blood flow velocities at positions at two ends of the interval and an interval length of the interval, and calculating a blood pressure difference between the positions at the two ends of the interval based on the vector blood flow velocities and the interval length;

displaying corresponding colors on different sections of the connecting line based on the magnitude of the blood pressure difference between the two end positions of each section so as to present the variation trend of the blood pressure difference between the first interest position and the second interest position.

2. A method of measuring an ultrasonic blood flow parameter, the method comprising:

acquiring a connecting line drawn on an ultrasonic image of a target blood vessel by a user, wherein the connecting line comprises a plurality of divided intervals;

and displaying corresponding colors on different sections of the connecting line based on the magnitude of the blood pressure difference between the two end positions of each section so as to present the variation trend of the blood pressure difference on the connecting line.

3. The method according to claim 1 or 2, wherein the vector blood flow velocity is calculated by a speckle tracking method, a transverse wave oscillation method, or a multi-angle deflection transmitting and/or receiving method based on the doppler principle.

4. The method of claim 1, wherein determining the connection between the first location of interest and the second location of interest comprises:

and automatically generating a connecting line between the first interesting position and the second interesting position according to the trend of the blood vessel in which the first interesting position and the second interesting position are positioned.

5. The method of claim 1, wherein determining the connection between the first location of interest and the second location of interest comprises:

generating a connecting line between the first and second locations of interest from a blood flow path of a blood vessel in which the first and second locations of interest are located.

6. The method according to claim 1 or 2, characterized in that the method further comprises:

in response to a selected manipulation of the blood pressure difference for an interval on the line, a corresponding blood pressure difference value is displayed.

7. The method according to claim 1 or 2, wherein when the magnitude of the blood pressure difference of a certain interval on the connection line is larger than a preset threshold value, it is indicated that the blood flow corresponding to the certain interval is abnormal.

8. A method of measuring an ultrasonic blood flow parameter, the method comprising:

transmitting ultrasonic waves to a target blood vessel along at least two different scanning angles, receiving echoes of the ultrasonic waves, and obtaining at least two groups of ultrasonic echo signals based on the echoes of the ultrasonic waves, wherein each group of ultrasonic echo signals is derived from the ultrasonic waves transmitted at one scanning angle;

acquiring a first position of interest and a second position of interest on an ultrasound image of the target vessel, and a length between the first position of interest and the second position of interest;

obtaining at least two velocity components at the first interest position and at least two velocity components at the second interest position respectively based on the at least two groups of ultrasonic echo signals, and synthesizing the at least two velocity components at each interest position to obtain a vector blood flow velocity at each interest position, wherein each velocity component is derived from one group of ultrasonic echo signals;

calculating a blood pressure difference between the first location of interest and the second location of interest based on the vector blood flow velocity at the first location of interest, the vector blood flow velocity at the second location of interest, and the length between the first location of interest and the second location of interest.

9. The method of claim 8, wherein the obtaining a length between the first location of interest and the second location of interest comprises:

and automatically generating a connecting line between the first interest position and the second interest position according to the trend of the blood vessel in which the first interest position and the second interest position are positioned, and determining the length between the first interest position and the second interest position based on the connecting line.

10. The method of claim 8, wherein the obtaining a length between the first location of interest and the second location of interest comprises:

generating a connecting line between the first interest position and the second interest position according to the blood flow path of the blood vessel in which the first interest position and the second interest position are located, and determining the length between the first interest position and the second interest position based on the connecting line.

11. The method according to any one of claims 8-10, further comprising:

acquiring a third location of interest on an ultrasound image of the target vessel and a length between the first location of interest and the third location of interest;

obtaining a vector blood flow velocity at the third location of interest based on the at least two sets of ultrasound echo signals;

calculating a blood pressure difference between the first location of interest and the third location of interest as a second blood pressure difference based on the vector blood flow velocity at the first location of interest, the vector blood flow velocity at the third location of interest, and the length between the first location of interest and the third location of interest;

calculating and outputting a difference between the first blood pressure difference and the second blood pressure difference, taking a blood pressure difference between the first interest location and the second interest location as a first blood pressure difference.

12. A method of measuring an ocular vascular index, the method comprising:

acquiring a blood pressure difference between a first interest position and a second interest position on an ultrasonic image of a target blood vessel, wherein the first interest position and the second interest position are respectively positioned in a common carotid artery and an internal carotid artery;

obtaining blood flow parameters of an ocular vessel communicating with the internal carotid artery, the blood flow parameters including a peak systolic flow rate and an end diastolic flow rate;

calculating a velocity difference between the peak systolic flow rate and the end diastolic flow rate, and calculating and outputting a ratio of the blood pressure difference to the velocity difference.

13. The method of claim 12, wherein the obtaining a blood pressure difference between a first location of interest and a second location of interest on an ultrasound image of a target vessel comprises:

acquiring respective vector blood flow velocities at a first and a second location of interest on an ultrasound image of the target vessel, and a length between the first and second location of interest;

calculating a blood pressure difference between the first and second locations of interest based on the vector blood flow velocity at the first location of interest, the vector blood flow velocity at the second location of interest, and the length between the first and second locations of interest.

14. The method of claim 12, wherein the obtaining a blood pressure difference between a first location of interest and a second location of interest on an ultrasound image of a target vessel comprises:

simultaneously obtaining respective blood flow velocities at a first interest position and a second interest position on an ultrasonic image of the target blood vessel based on a multipoint pulse Doppler method;

calculating a blood pressure difference between the first and second locations of interest based on the blood flow velocity at the first and second locations of interest.

15. The method of claim 12, wherein the obtaining a blood pressure difference between a first location of interest and a second location of interest on an ultrasound image of a target vessel comprises:

acquiring a blood flow velocity at a maximum stenosis of an internal carotid artery between a first interest position and a second interest position on an ultrasound image of the target vessel;

calculating a blood pressure difference between the first and second locations of interest based on a blood flow velocity at the maximum narrowing of the internal carotid artery.

16. The method according to any one of claims 12 to 15, further comprising:

comparing the ratio with a preset threshold value, and outputting prompt information according to a comparison result;

when the ratio is greater than a preset threshold, the prompt message includes: the ocular vessels are highly likely to have ischemia, and/or the cause of ischemia is highly correlated with carotid stenosis;

when the ratio is smaller than a preset threshold, the prompt message includes: the ocular vessels are less likely to have ischemia, or the cause of ischemia is less associated with carotid stenosis.

17. The method of any one of claims 12 to 15, wherein the peak systolic flow rate and the end diastolic flow rate are blood flow velocities measured based on pulse doppler.

18. The method of any one of claims 12 to 15, wherein the ocular vessel comprises at least one of an ocular artery, a central retinal artery, a ciliary artery.

19. An ultrasonic blood flow imaging apparatus, comprising a transmitting circuit, a receiving circuit, an ultrasonic probe, a processor and a display, wherein:

the transmitting circuit is used for controlling the ultrasonic probe to transmit ultrasonic waves to a target part of a target object;

the receiving circuit is used for controlling the ultrasonic probe to receive the echo of the ultrasonic wave and acquiring an ultrasonic echo signal from the echo of the ultrasonic wave;

the processor is used for carrying out ultrasonic blood flow imaging based on the ultrasonic echo signal;

the processor is further configured to perform the method of measuring an ultrasound blood flow parameter of any one of claims 1-18;

the display is used for displaying the result output by the processor.