阅读说明：本技术 一种超声彩色血流成像控制方法 (Ultrasonic color blood flow imaging control method ) 是由 杨姣姣 何蕾 于 2021-09-08 设计创作，主要内容包括：为了提高超声彩色血流的帧频,并输出分辨力不受损的血流速度图,发明了一种超声彩色血流成像技术。首先,基于发射扫描密度参数设置彩色血流发射控制方式,即随着扫描密度等级的变化,形成一种对应的控制发射工作方式。其中,扫描密度设置为多级可调,每一级对应一种发射工作方式,不同的工作方式具有不同的发射扫描线间距离。然后,针对接收的回波数据,根据对应的发射扫描线间距离,构造虚拟接收线数据形成新的接收数据组。最后,对新的接收数据进行相应的后处理并插值输出图像。经实验验证,特别是对于一些逻辑资源、存储资源和传输速率受限的平台,一种增加发射扫描线间距离并构造虚拟接收线数据的方法,不仅能够提高彩色血流成像帧率,而且能够保证图像的分辨力不受影响。(In order to improve the frame frequency of the ultrasonic color blood flow and output a blood flow velocity map without damaging the resolution, the invention provides an ultrasonic color blood flow imaging technology. Firstly, a color blood flow emission control mode is set based on an emission scanning density parameter, namely, a corresponding emission control working mode is formed along with the change of the scanning density grade. The scanning density is set to be adjustable in multiple stages, each stage corresponds to one emission working mode, and different working modes have different distances between emission scanning lines. Then, for the received echo data, virtual receiving line data is constructed according to the distance between the corresponding transmitting scanning lines to form a new receiving data group. And finally, carrying out corresponding post-processing on the new received data and carrying out interpolation to output an image. Experiments prove that particularly for platforms with limited logic resources, storage resources and transmission rates, the method for increasing the distance between the transmitting scanning lines and constructing the virtual receiving line data can not only improve the color blood flow imaging frame rate, but also ensure that the resolution of the image is not influenced.)

1. An ultrasonic color blood flow imaging control method comprises the following characteristics:

the emission scanning density of ultrasonic color blood flow imaging is set to be multistage adjustable, each stage corresponds to the distance between one emission scanning line, emission of each scanning line is completed by controlling emission scanning according to the distance between the scanning lines and the number of the array elements at intervals, so that the emission time of each frame is controllable, and particularly, when higher frame frequency is required, the level of the scanning density can be increased and the number of the array elements at intervals of the scanning lines can be increased;

the emission control unit reduces the emission scanning lines by increasing the distance between the emission lines, so that the relative resource requirement is lower, the phenomenon of reducing resource power consumption is realized, and the data transmission is reduced while the logic control task amount is reduced, so that the emission control unit can adapt to some devices with limited transmission rate and storage resources;

calculating the average power coefficient of real received echo data corresponding to different physical positions in each working mode according to the physical distance between the color blood flow image and the corresponding two-dimensional mode and the physical position relation of each line sequence, and forming a compensation coefficient template to be stored in equipment;

based on each frame of received original data, virtual receiving line data are constructed and correspondingly compensated, expansion reconstruction of the original data is formed, and uniformity of the data is guaranteed.

2. The ultrasound color flow imaging control method according to claim 1, characterized by controlling the operation mode of the emission control unit, specifically:

the emission scanning density is set to be multistage adjustable, the number of the set levels can be set according to the available resource quantity and the imaging quality requirement of a detected image, and when the available resource is limited, the emission scanning density grade can be improved, namely the distance between the emission scanning lines is increased; when a receptor image to be detected shows more details, the received data is required not to lose echo information, namely, the inter-line distance of the transmitting scanning lines cannot be too large and generally does not exceed 4 times of the array element spacing of the ultrasonic probe;

the distance between the emission scanning lines is not limited to integral multiples of the array element spacing of the probe, and specifically, the distance can be set to be selectable in multiple stages according to requirements and resource conditions, wherein each stage corresponds to an emission scanning working mode.

3. The ultrasound color flow imaging control method according to claim 2, characterized in that the emission occupancy duration and resource requirements are changed according to the control of the operating mode of the generation control unit, in particular for resource-constrained platforms, specifically: the distance between the transmitting lines is increased to reduce the transmitting scanning lines, so that fewer scanning lines are adopted for scanning a frame of image, the data transmission quantity is reduced, the requirements of logic resources and storage resources are reduced, even the transmission rate is not high, the transmitting time is saved, the frame frequency is improved, and the method has stronger applicability to platforms with limited logic resources, storage resources and transmission rate.

4. The method of claim 1, wherein the compensation coefficient template is formed by calculating an average power coefficient based on echo data of the receive lines at different physical locations under different transmit modes.

5. The method according to claim 1, wherein the generation control unit is configured to construct corresponding virtual receive line data according to an operation mode setting, and the compensation coefficient is searched according to the scan density to compensate the virtual receive line data, so as to form a new receive data set, specifically:

constructing virtual receiving line data based on original receiving data in an interpolation reconstruction mode according to the distance between transmitting scanning lines, the physical distance between the lines corresponding to the two-dimensional mode and the physical position relationship of the scanning line sequence, searching a product of a compensation coefficient and the virtual receiving line data for compensation, and then recombining the compensation coefficient and the original receiving data to form new dimension expanded receiving data;

the interpolation method is not limited to bilinear interpolation and spline interpolation, and the interpolation coefficient needs to be calculated based on the physical distance between the original colorful blood flow data lines and the physical position relation between the corresponding two-dimensional lines, so that the distance between the data lines after virtual reconstruction is not more than the distance between the corresponding B modes, and even is approximate to half of the distance between the corresponding B modes.

6. An ultrasound color flow imaging control method, characterized in that, the method comprises the steps of controlling the multistage working mode of the emission control unit and expanding and reconstructing the received data, and the ultrasound blood flow imaging control method according to any one of claims 1 to 5 is realized for an ultrasound blood flow imaging system, and the purpose is to enable a platform with limited resources to realize a high frame rate of ultrasound color flow imaging without influencing the resolution.

7. An ultrasound color flow imaging control method, characterized by a processor and a memory, said memory having a computer program thereon, said computer program, when executed by said processor, implementing the ultrasound flow imaging control method according to any of claims 1-5.

8. A computer storage medium having a computer control program stored thereon, wherein the computer control program, when executed by a processor, implements the ultrasound color flow imaging control method of any of claims 1-5 by controlling an ultrasound imaging system.

Technical Field

The invention relates to the field of ultrasonic color blood flow imaging, in particular to a front-end control transmitting working mode of ultrasonic color blood flow and expansion reconstruction of received data, aiming at improving the frame frequency of color blood flow imaging and simultaneously keeping the resolution of an original image.

Background

As one of four medical imaging technologies, the ultrasonic imaging technology is widely applied due to the advantages of non-invasive property, safety, convenience for real-time detection of patients and the like. Ultrasound imaging relies on a powerful imaging system. The ultrasonic imaging system mainly comprises an ultrasonic probe, a high-voltage pulse transmitting unit, a receiving sound beam forming unit, a system overall control unit, a transmission and cache unit, an echo post-processing unit, an image display unit and a related processing unit. Wherein, the emission control is that short pulse mechanical waves (1-16 MHz) are generated by an emitting unit and then ultrasonic waves are emitted to a receptor through an ultrasonic probe. The ultrasonic wave is reflected when entering the body of the receptor and meets the tissue of the receptor, and the reflected signal is received by the ultrasonic probe and then converted into an electric signal which is processed by the receiving control module to form received echo data. The ultrasound image can be output and displayed by carrying out a series of post-processing on the echo data.

As an important ultrasound imaging technology, ultrasound color blood flow imaging combines B-mode ultrasound imaging and doppler blood flow detection technology, and superimposes a color-coded blood flow velocity map on a two-dimensional grayscale image reflecting the structure of a detected receptor object, so that the blood flow velocity distribution in a region of interest can be visually displayed in real time, which has become an indispensable part in current ultrasound diagnostic equipment. Unlike B-mode ultrasound imaging, ultrasound color flow imaging has significant technical differences in the transmit control unit, the receive processing unit, and the post-processing module. At the transmit control unit, ultrasound color flow imaging requires the transmission of short-time pulses at certain time intervals (pulse interval periods, PRI). In the receiving control unit, multiple times of echo data need to be received sequentially at the same scanning line position (the transmission times are set to be 8-16 times by a common ultrasonic imaging diagnostic system). In the post-processing unit, the ultrasonic color flow imaging is based on the Doppler imaging technology to calculate the average phase change of the slow-time signal.

With the improvement of the current ultrasound imaging technology, the B mode is often the first mode for medical applications due to its higher resolution and frame rate. Ultrasound color flow imaging also has irreplaceable medical assistance diagnostic value. However, the ultrasound color flow imaging exists in that the same scanning line is transmitted for a plurality of times at certain time intervals, so that the transmission time consumption becomes a main factor for reducing the frame rate. Multiple emission according to a certain time interval is the key of color blood flow imaging, and even in order to improve the blood flow detection capability, more emission times are needed for the same scanning line, so that the emission takes longer time. In order to meet different detection requirements and make the imaging frame frequency adjustable, a method for controlling the emission occupation time based on the scanning density is necessary.

So-called control of emission scan density, that is, control of inter-line distance of emission scan lines. For a set detection interest area, when the distance between scanning lines is larger, less scanning lines can be used for completing scanning of a frame of image, the emission scanning time is reduced, the frame frequency is improved, but the scanning lines are also more sparse, partial blood flow echo information can be omitted, and the detail resolution of the original image is lost. As the distance between scan lines is smaller, more scan lines are required to complete the scan, which increases scan time, decreases imaging frame rate, and may not even meet diagnostic requirements. It can be seen that scan density has a large influence on the imaging frame rate and image resolution.

At present, although various methods for improving the frame frequency and resolution of ultrasound imaging are diversified, the methods mostly have tedious control flows and complex calculation models, which also have high requirements on equipment resources and increase the resource cost to a certain extent. For some platforms with limited resources, especially for some devices with limited logic resources, storage resources and transmission rates, the method can not only improve the ultrasonic color blood flow imaging frame frequency, but also ensure that the image resolution is not affected, and has a simple and feasible control flow.

Disclosure of Invention

In order to solve the above problems, particularly for some devices with limited logic resources, storage resources, and transmission rates, the present invention provides an ultrasound color flow imaging control technique, which is intended to improve the color flow imaging frame rate and ensure that the resolution of image details is not affected.

In order to achieve the technical purpose, the technical scheme for controlling the ultrasonic color blood flow imaging provided by the invention comprises the following implementation steps.

The emission scanning density of the ultrasonic color blood flow imaging is set to be adjustable in multiple stages, and each stage corresponds to different distances between scanning lines. For example, the emission scan density is set to be adjustable in 4 steps, wherein the distance between the emission scan lines corresponding to the 1 st step, the 2 nd step, the 3 rd step and the 4 th step is 1 time, 2 times, 3 times and 4 times of the array element spacing of the ultrasonic probe.

The gradation setting regarding the emission scan density and the inter-scan line distance setting include, but are not limited to, the above examples.

The working mode of the transmitting unit is controlled according to the set scanning density level, when the ultrasonic color blood flow imaging needs a very high frame rate, the scanning density level can be set to be maximum, the transmitting control unit controls the transmitting scanning lines to transmit according to the set maximum array element interval, after the repeated transmission (transmitting repetition frequency, PRF) of one scanning line is completed, the repeated transmission of the next scanning line is started according to the set maximum array element interval, and all array elements corresponding to the interest area are traversed in sequence.

Through the control mode, the number of the transmitting scanning lines can be reduced, the transmitting time is also saved, the detail resolution of an original image is lost even possibly due to the omission of blood flow echo information in order to avoid the situation that the echo data is too sparse, and the distance between the transmitting scanning lines is generally not more than 4 times of the array element distance of the ultrasonic probe.

And starting scanning according to the set transmitting working mode, finishing beam forming of the received data by the receiving control module to form original received data, and transmitting and caching the original received data.

Each scanning line is provided with multiple corresponding echo data, and the inter-line distance between the scanning lines can be calculated through transmitting the number of interval array elements to obtain the inter-line physical distance Lc.

And calculating the inter-line physical distance Lb of the region of interest corresponding to the B mode.

And calculating the number of the receiving virtual lines required to be constructed according to the distance Lb between the B-mode lines and the distance Lc between the color blood flow lines, so that the distance between the reconstructed color blood flow lines is not more than Lb and even equal to half of Lb.

According to the steps, the original receiving echo data of the ultrasonic color blood flow is subjected to receiving line data interpolation by a method based on linear interpolation, so that the total receiving line number in the interest area is not less than or even more than 2 times of the corresponding B mode line number. A reorganization of the virtual data and the original data can be obtained. And the virtual receiving line data is compensated based on the template compensation coefficient, so that the uniformity of the corresponding color blood flow data in the interest area is better. And the template compensation coefficient is obtained by calculation according to the power relation of the echo data of the receiving line corresponding to each physical position in the same transmission working mode.

The compensation coefficient template is constructed by calculating an average power coefficient list of received echo data corresponding to each physical position under the same transmission working mode, namely, the compensation coefficient values corresponding to different physical receiving positions are calculated according to the set transmission working mode and stored in the equipment as template parameters, and the template is searched by looking up the table through the transmission scanning density grade, so that the recombined data distribution of the virtual receiving line data and the original data is more uniform. In particular, in order to make the output line data more uniform, appropriate optimization adjustment can be performed without changing the magnitude relation of the template compensation values.

The constructed template compensation coefficient is an average power relation coefficient of echo data of the receiving line corresponding to each physical position obtained by detecting a standard uniform tissue body membrane under the condition of the same transmission working mode, and the value of the average power relation coefficient is generally larger than 1. For example, when the scan lines are transmitted at an interval of one array element, and virtual 2 pieces of receive data are needed between two pieces of real receive line data, and the physical positions corresponding to the 2 pieces of receive data are all aligned with the center of the array element cutting gap, the average power coefficient is calculated to be 1.8, and the compensation coefficients of the corresponding 2 pieces of virtual receive line data under the condition can be set to be all. In practice, this example is included but not limiting, and the example is not intended to limit the invention.

For any constructed raw data of a receiving virtual line, multiple times of corresponding receiving echo data need to be constructed, that is, each virtual receiving line has multiple times of corresponding receiving echoes.

That is to say, the dimensions of the slow signals corresponding to the reconstructed color blood flow data in the region of interest are the same, and the dimension of the fast signals is not less than the dimension of the fast signals corresponding to the B mode in the region, or even more than 2 times of the number of lines of the B mode corresponding to the fast signals.

In the above, the slow signal dimension refers to the number of times of repeated emission of each scan line, and the fast signal dimension refers to the number of scan lines.

And carrying out post-processing on the reconstructed blood flow data, including filtering wall motion, calculating autocorrelation, acquiring a blood flow characteristic diagram, carrying out smooth optimization processing, interpolating a blood flow velocity diagram, mapping color codes, controlling noise suppression and outputting and displaying.

The method for filtering the wall includes, but is not limited to, high-pass filtering, regression, feature space decomposition and the like, the blood flow feature map includes a blood flow velocity map, a blood flow power map and a blood flow variance map, optimization processing relates to removing abnormity, smoothing, enhancing boundary, continuity and the like, the blood flow velocity map interpolation method can adopt bilinear interpolation, cubic spline interpolation and the like, noise suppression control can be controlled based on two-dimensional structure information and relevant threshold values, and color coding mapping is required before output and display.

The present invention focuses on a transmission control scheme based on scan line density and a method of constructing virtual receive line data by which the imaging frame rate can be improved to a certain extent without losing detail resolution of the image.

The invention relates to a method for expanding and reconstructing received data, which utilizes the distance relation between data lines and the average power coefficient of echo signals of each physical position, thereby not only increasing the data density and ensuring the uniformity between the data lines, but also ensuring no loss of the image resolution obtained by post-processing the reconstructed data.

Drawings

Fig. 1 is a system block composition for ultrasound color flow imaging.

Fig. 2 is a flowchart of an ultrasound color blood flow imaging control method provided by the present invention.

Fig. 3 and fig. 4 are exemplary diagrams of a method for constructing virtual receive line data according to the present invention.

Fig. 5 is an example of a template compensation coefficient list of virtual receive line data according to the present invention.

Fig. 6 is a diagram illustrating resource occupation and comparison of the ultrasound color blood flow imaging control method provided by the present invention. The left light colored bar is an embodiment of the present invention that constructs the percentage of the resource usage of 3 virtual receive lines between real receive lines as exemplified in fig. 5. The right side dark columnar bar is the percentage of the occupied resource when the emission working mode is the same, but the actual number of receiving lines is 4 times; the exemplary figures are only intended to illustrate one resource usage scenario implemented in accordance with the present invention and are not intended to limit the present invention.

Fig. 7 is an exemplary diagram of a target point obtained by an ultrasonic blood flow imaging control method according to the present invention, in which a detection receptor is a standard body membrane, an upper image is an example of an output two-dimensional image of the present invention, and a lower image is an example of a contrast image, both of which are two-dimensional grayscale images obtained based on ultrasonic blood flow echo data. In particular, the present exemplary image is for explanation of the present invention only and is not intended to limit the present invention.

Detailed Description

In order to more intuitively describe the method of the present invention, the following will be further described in detail with reference to the implementation flow chart and implementation example of the present invention. The embodiments described herein are merely illustrative of the present invention and are not to be construed as limiting the invention.

Examples of the implementation

Referring to fig. 2, an example of the present invention provides an ultrasound color blood flow imaging control method, which will be referred to as the present method hereinafter, and the implementation includes the following steps.

Step 1, setting the emission scanning density of ultrasonic color blood flow in a region of interest as level 2.

And 2, setting the interval distance between the scanning lines to be 2 times of the array element interval of the probe by the emission control unit according to the set emission scanning density.

And 3, carrying out emission control according to the set emission working mode, and setting the Pulse Repetition Frequency (PRF) of multiple emission of a single scanning line as an empirical value for detecting the receptor.

And 4, sequentially receiving the echo data of each scanning line to form a frame of received data, wherein the number of the scanning lines is nL 0.

And 5, calculating the physical distance Lc between lines of each frame of blood flow echo data, calculating the corresponding distance Lb between lines of the B mode, and calculating the number of virtual lines required to be constructed and the total receiving line number nL1 after data reconstruction.

And 6, interpolating the original data with the number of nL0 lines in each frame based on the line sequence physical position to enable the number of the interpolated data lines to be nL1, and compensating the virtual receiving line data based on the template compensation coefficient to form new reconstructed receiving data. The virtual receive line data is also volumetric data, with a slow signal dimension that is uniformly cross-distributed with the original data in the scan dimension. The interpolation method can adopt, but is not limited to, linear interpolation, the compensation coefficient template is an average power coefficient calculated based on the entity echo data and is stored in the device, and the virtual receiving line data is compensated by multiplying the virtual receiving line data by the template compensation coefficient corresponding to the line sequence. As shown in fig. 3, for example, the interval is 2 array element intervals, 1 piece of virtual receiving line data is constructed between lines, a compensation coefficient template is searched, and the compensation coefficient is obtained according to fig. 5. As an example in fig. 4, the data is obtained by constructing 3 virtual receiving lines between lines at intervals of 2 array element intervals, the physical positions of the left and right virtual receiving lines are aligned with the center of the gap between the array elements, the middle of the virtual receiving lines is aligned with the center of the array element, the compensation coefficient template in fig. 5 is searched, and the obtained compensation coefficients are sequentially sum from left to right.

And 7, performing post-processing on the reconstructed received data after interpolation, wherein the post-processing comprises wall motion filtering, autocorrelation calculation, blood flow velocity diagram and power diagram calculation, blood flow velocity diagram optimization enhancement, blood flow velocity diagram noise suppression based on a characteristic threshold, blood flow velocity diagram interpolation based on pixels, blood flow velocity diagram color coding mapping and blood flow color image output display, as shown in fig. 1.

In particular, based on the emission control method of the method, after one frame of original blood flow echo data is buffered by transmission, the output images of the two processing methods are implemented and analyzed, as shown in fig. 7. Firstly, virtual receiving line data is constructed according to the method, a new receiving data group is formed, and then corresponding post-processing is carried Out to obtain a two-dimensional gray scale output image Out1 of color blood flow data. Second, the received frame data is directly processed to obtain a two-dimensional gray scale output image Out2 of color blood flow data without constructing virtual receive line data. It can be considered that the resolution of Out1 is stronger than that of Out 2.

Particularly, for some devices with limited logic resources, storage resources and transmission rates, by implementing the method, the ultrasonic color blood flow frame frequency can be improved, the image resolution can be ensured, and the auxiliary diagnosis requirement can be met under the condition of limited resource configuration.

The above-described embodiments of the present invention, including but not limited to the examples, do not limit the scope of the present invention. Any other various corresponding changes and modifications made according to the technical idea of the present invention are included in the scope of the claims.