Vascular imaging method and apparatus

Abstract

The application discloses a blood vessel imaging method and device. In the method, after a blood vessel imaging device acquires a first echo image, a second echo image and a transverse relaxation image, the blood vessel imaging device can determine a reference echo image with the same echo time as the second echo image based on the first echo image and the transverse relaxation image, and subtract the reference echo image from the second echo image to obtain a target blood vessel image. Since the reference echo image is determined based on the first echo image and the transverse relaxation image, the amplitude of non-blood vessel information in the reference echo image is basically consistent with the amplitude of non-blood vessel information in the second echo image, and by subtracting the reference echo image from the second echo image, a blood vessel image with complete non-blood vessel information suppression can be obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical treatment, in particular to a blood vessel imaging method and device. BACKGROUND

[0002] Non-contrast-enhanced magnetic resonance angiography (NCE-MRA) is a non-enhanced blood vessel imaging technology, which is widely used in clinical practice due to its high safety and low cost.

[0003] In the related art, after the blood vessel imaging device acquires two echo images in one repetition period, the blood vessel imaging device can obtain a blood vessel image based on the two echo images by using a linear subtraction method. One of the two echo images contains non-blood vessel features and blood vessel features, and the other echo image contains blood vessel features.

[0004] However, due to the inconsistency of the amplitudes of the two echo images, the non-blood vessel features in the blood vessel image obtained by subtraction are not completely suppressed. SUMMARY

[0005] The present application aims to at least partially solve one of the technical problems in the related art. To this end, one object of the present application is to provide a blood vessel imaging method and device. In the method, after the blood vessel imaging device acquires a first echo image, a second echo image and a transverse relaxation image, the blood vessel imaging device can determine a reference echo image with the same echo time as the second echo image based on the first echo image and the transverse relaxation image, and subtract the reference echo image from the second echo image to obtain a target blood vessel image. Since the reference echo image is determined based on the first echo image and the transverse relaxation image, the amplitude of the non-blood vessel information in the reference echo image is basically consistent with the amplitude of the non-blood vessel information in the second echo image. By subtracting the reference echo image from the second echo image, a blood vessel image with complete non-blood vessel information suppression can be obtained.

[0006] In one aspect, a blood vessel imaging method is provided, the method comprising:

[0007] acquiring a first echo image and a second echo image with different echo times in the same repetition period, the first echo image containing blood vessel information and non-blood vessel information, and the second echo image containing non-blood vessel information;

[0008] acquiring a transverse relaxation image, the transverse relaxation image including blood vessel information and non-blood vessel information;

[0009] determining a reference echo image with the same echo time as the second echo image based on the first echo image and the transverse relaxation image;

[0010] Subtract the reference echo image from the second echo image to obtain a target blood vessel image.

[0011] Optionally, the transverse relaxation image is obtained by:

[0012] The third echo image and the fourth echo image are obtained, the third echo image and the fourth echo image being different in echo time and being in the same repetition period, and the transverse relaxation image is obtained based on the third echo image and the fourth echo image, the third echo image and the second echo image being in different repetition periods, and the third echo image and the fourth echo image both containing blood vessel information and non-blood vessel information.

[0013] Alternatively, the fifth echo image is obtained, and the transverse relaxation image is obtained based on the fifth echo image and the first echo image, the fifth echo image and the first echo image being in the same repetition period, the fifth echo image containing blood vessel information and non-blood vessel information, and the echo time of the fifth echo image being different from the echo time of the first echo image.

[0014] Optionally, the echo time of the fifth echo image and the echo time of the first echo image are both less than the echo time of the second echo image.

[0015] Optionally, the transverse relaxation image is obtained by:

[0016] A first ratio of a plurality of first amplitudes of the first target echo image to a plurality of second amplitudes of the second target echo image is determined.

[0017] A time difference value of the echo time of the second target echo image to the echo time of the first target echo image is determined.

[0018] For each first ratio, a transverse relaxation time of a pixel in the transverse relaxation image is determined based on the first ratio and the time difference value.

[0019] If the first target echo image includes the third echo image, the second target echo image includes the fourth echo image, if the first target echo image includes the fifth echo image, the second target echo image includes the first echo image, the transverse relaxation time is negatively correlated with the first ratio and positively correlated with the time difference value.

[0020] Optionally, the transverse relaxation time T2*i of the i-th pixel satisfies:

[0021] ΔTE is the time difference value, and Si is the i-th first ratio.

[0022] Optionally, the reference echo image with the same echo time as the second echo image is determined based on the first echo image and the transverse relaxation image, comprising:

[0023] A second ratio of the transverse relaxation time of each pixel in the transverse relaxation image to the time difference value is determined.

[0024] determine a plurality of fourth amplitudes of the reference echo image based on the plurality of third amplitudes and the plurality of second ratios;

[0025] wherein the fourth amplitudes are positively correlated with the third amplitudes and the second ratios.

[0026] Optionally, the ith fourth amplitude S22i satisfies:

[0027] S21i is the ith third amplitude, and T2*i is the transverse relaxation time of the ith pixel.

[0028] Optionally, the transverse relaxation time of each pixel in the transverse relaxation image indicates the transverse relaxation time of the blood vessel information and the non-blood vessel information of the pixel.

[0029] Optionally, the first echo image is acquired after flow velocity compensation, and the second echo image is acquired after flow velocity encoding.

[0030] In another aspect, a computer readable storage medium is provided, having stored thereon a blood vessel imaging program, which, when executed by a processor, implements the blood vessel imaging method of the above aspect.

[0031] In yet another aspect, a blood vessel imaging device is provided, comprising a memory, a processor, and a blood vessel imaging program stored on the memory and executable on the processor, wherein the processor implements the blood vessel imaging method of the above aspect when executing the blood vessel imaging program.

[0032] In yet another aspect, a blood vessel imaging apparatus is provided, the apparatus comprising:

[0033] a signal acquisition module configured to acquire a first echo image and a second echo image with different echo times within a same repetition period, the first echo image containing blood vessel information and non-blood vessel information, and the second echo image containing non-blood vessel information;

[0034] a first image acquisition module configured to acquire a transverse relaxation image, the transverse relaxation image including blood vessel information and non-blood vessel information;

[0035] a second image acquisition module configured to determine a reference echo image with the same echo time as the second echo image based on the first echo image and the transverse relaxation image, and subtract the reference echo image from the second echo image to obtain a target blood vessel image.

[0036] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 is a flowchart of a blood vessel imaging method provided by an embodiment of the present application;

[0038] Figure 2 is a flowchart of another blood vessel imaging method provided by an embodiment of the present application;

[0039] Figure 3 is a schematic diagram of echo images acquired in the same repetition period provided by an embodiment of the present application;

[0040] Figure 4 is a schematic diagram of another echo images acquired in the same repetition period provided by an embodiment of the present application;

[0041] Figure 5 is a schematic diagram of still another echo images acquired in the same repetition period provided by an embodiment of the present application;

[0042] Figure 6 is a schematic diagram of a transverse relaxation image provided by an embodiment of the present application;

[0043] Figure 7 is a schematic diagram of a SWI provided by an embodiment of the present application;

[0044] Figure 8 is a schematic diagram of a non-enhanced arterial and venous vessel image provided by an embodiment of the present application;

[0045] Figure 9 is a schematic diagram of another non-enhanced arterial and venous vessel image provided by an embodiment of the present application;

[0046] Figure 10 is a schematic diagram of still another non-enhanced arterial and venous vessel image provided by an embodiment of the present application;

[0047] Figure 11 is a schematic diagram of a blood vessel imaging device provided by an embodiment of the present application;

[0048] Figure 12 is a block diagram of a blood vessel imaging apparatus provided by an embodiment of the present application;

[0049] Figure 13 is a block diagram of a first image acquisition module provided by an embodiment of the present application. DETAILED DESCRIPTION

[0050] Embodiments of the present application are described in detail below with reference to the attached drawing figures, wherein the same or like reference numerals are used throughout the drawing figures to refer to the same or like elements or elements having the same or similar functionality. The embodiments described below are exemplary and are intended to be illustrative of the present application and are not to be construed as limiting thereof.

[0051] Magnetic resonance imaging (MRI) is one of the main imaging methods in modern medical imaging, and is widely used in medical imaging. Magnetic resonance angiography (MRA) is an important application in the practice of magnetic resonance imaging. Magnetic resonance angiography can include contrast-enhanced magnetic resonance angiography (CE-MRA) and NCE-MRA. The NCE-MRA is to use the information of the evolution of the blood vessel signal in magnetic resonance, and through the special sequence acquisition method, the contrast of the blood vessel signal is improved. Moreover, as a non-enhanced blood vessel imaging technology, NCE-MRA is widely used in clinical practice due to its high safety and low cost.

[0052] Among them, non-enhanced blood vessel imaging can include susceptibility weighted imaging (SWI), magnetic resonance angiography imaging (MRA), and magnetic resonance angiography and venography imaging (MRAV). SWI is mainly used for observing venous vessels, hemorrhage, calcification and iron deposition, etc. Arterial vessel imaging (MRA) or arterial and venous vessel imaging (MRAV) is mainly used for observing the distribution of arterial or venous vessels and pathological information.

[0053] In the related art, after the blood vessel imaging device acquires two echo images in one repetition period, a linear subtraction method can be used to obtain a blood vessel image based on the two echo images. Among them, one of the two echo images contains blood vessel features and non-blood vessel features, and the other echo image contains blood vessel features.

[0054] However, due to the inconsistency of the amplitudes of the two echo images, the non-blood vessel information of the blood vessel image obtained by linear subtraction is not completely suppressed. The non-blood vessel information can include static tissues (such as brain gray matter and white matter, skull, etc.), and the non-blood vessel information is not completely suppressed, which can cause the distribution and pathological information of the blood vessels to be unable to be clearly displayed, thereby interfering with clinical diagnosis.

[0055] In an example, the amplitude of one echo image is denoted by s1, and the amplitude of the other echo image is denoted by s2. Using the linear subtraction method, the amplitude S of the blood vessel image obtained based on the one echo image and the other echo image is sub S can satisfy: S sub = s1-λ×s2.

[0056] wherein λ is a constant, usually derived from experience, and the purpose is to increase the amplitude of non-vascular information in another echo image, ensure the same as the amplitude of non-vascular information in the one echo image, so as to achieve the purpose of suppressing non-vascular information and enhancing the contrast of blood vessels.

[0057] However, in clinical imaging, since the imaging region is not composed of a single component of non-vascular information, the blood vessel image obtained by using the above linear subtraction method cannot completely suppress the non-vascular information. For example, in the head NCE-MRA (determined based on the above linear subtraction method) image, the static tissue in the gray matter region of the brain tissue is usually completely suppressed, but the static tissue in the skull region of the brain is not completely suppressed.

[0058] Figure 1 is a flowchart of a blood vessel imaging method provided by an embodiment of the present application, as shown in Figure 1 The method comprises the following steps.

[0059] Step 101: acquiring a first echo image and a second echo image with different echo times in the same repetition period.

[0060] The blood vessel imaging device can acquire a first echo image and a second echo image with different echo times in the same repetition period, wherein the first echo image contains blood vessel information and non-vascular information, and the second echo image contains non-vascular information. It can be understood that, since the echo times of the first echo image and the second echo image are different, the non-vascular information in the first echo image and the non-vascular information in the second echo image have the same position but different signal intensities in the image. In the image domain, the position can include pixel coordinates. Different pixel positions in the image can represent the same or different tissues, and the tissues can include blood vessels and non-vascular parts in the present application. In the following, the understanding of the blood vessel information and the non-vascular information in different echo images can refer to this paragraph.

[0061] Step 102: acquiring a transverse relaxation image.

[0062] The blood vessel imaging device can further acquire a transverse relaxation image after acquiring the first echo image and the second echo image, wherein the transverse relaxation image can include blood vessel information and non-vascular information. It can be understood that the blood vessel information in the transverse relaxation image corresponds to the position of the blood vessel information in the first echo image in the image, but the meaning of each pixel is different, and the non-vascular information in the transverse relaxation image corresponds to the position of the non-vascular information in the first echo image (or the non-vascular information in the second echo image) in the image, but the meaning of each pixel is different.

[0063] Step 103: determining a reference echo image with the same echo time as the second echo image based on the first echo image and the transverse relaxation image.

[0064] The blood vessel imaging device can determine a reference echo image with the same echo time as the second echo image based on the first echo image and the transverse relaxation image. Since the reference echo image is determined based on the first echo image and the transverse relaxation image, the reference echo image contains the blood vessel information and the non-blood vessel information of the first echo image, and the difference between the amplitude of the non-blood vessel information in the reference echo image and the amplitude of the non-blood vessel information in the second echo image is less than the difference threshold.

[0065] It can be understood that in the case where the difference between the amplitude of the non-blood vessel information in the reference echo image and the amplitude of the non-blood vessel information in the second echo image is less than the difference threshold, the amplitude of the non-blood vessel information in the reference echo image is basically consistent with the amplitude of the non-blood vessel information in the second echo image.

[0066] Step 104, subtracting the reference echo image from the second echo image to obtain a target blood vessel image.

[0067] After the blood vessel imaging device determines the reference echo image, the reference echo image can be subtracted from the second echo image to obtain a target blood vessel image.

[0068] In summary, the embodiment of the present application provides a blood vessel imaging method. After the blood vessel imaging device obtains the first echo image, the second echo image and the transverse relaxation image, the blood vessel imaging device can determine a reference echo image with the same echo time as the second echo image based on the first echo image and the transverse relaxation image, and subtract the reference echo image from the second echo image to obtain a target blood vessel image. Since the reference echo image is determined based on the first echo image and the transverse relaxation image, the amplitude of the non-blood vessel information in the reference echo image is basically consistent with the amplitude of the non-blood vessel information in the second echo image. By subtracting the reference echo image from the second echo image, a blood vessel image with complete non-blood vessel information suppression can be obtained.

[0069] Figure 2 is a flowchart of another blood vessel imaging method provided by the embodiment of the present application, as shown in Figure 2 The method comprises the following steps:

[0070] Step 201, obtaining a first echo image and a second echo image with different echo times in the same repetition period.

[0071] The blood vessel imaging device can obtain a first echo image and a second echo image with different echo times in the same repetition period. The periods of the first echo image and the second echo image are the same, and the first echo image contains blood vessel information and non-blood vessel information, i.e., the first echo image is a magnetic resonance bright blood signal. The blood vessel information can include arterial blood vessel information and venous blood vessel information, and the non-blood vessel information can include venous tissue.

[0072] Optionally, the first echo image is acquired after flow velocity compensation processing, and the proton signals with flow characteristics are retained, so that the first echo image contains blood vessel information and non-blood vessel information.

[0073] The second echo image is acquired after flow velocity encoding processing, and the proton signals with flow characteristics are lost, so that the second echo image does not contain blood vessel information, i.e., the second echo image is a dark blood signal containing non-blood vessel information. Moreover, the echo time of the first echo image is less than the echo time of the second echo image.

[0074] Reference Figure 3 And Figure 4 In the same repetition period TR, a flow compensation (FC) module is applied before acquiring the first echo image echo 11, and a flow encoding (FE) module is applied before acquiring the second echo image echo 12.

[0075] In step 202, a transverse relaxation image is acquired.

[0076] The blood vessel imaging device can further acquire a transverse relaxation image after acquiring the first echo image and the second echo image.

[0077] In an optional implementation of an embodiment of the present application, the blood vessel imaging device can further acquire a third echo image and a fourth echo image in the same repetition period and with different echo times, and acquire a transverse relaxation image based on the third echo image and the fourth echo image. The third echo image is in a different repetition period from the second echo image, and the third echo image and the fourth echo image both contain blood vessel information and non-blood vessel information.

[0078] The first echo image and the second echo image are acquired in a first repetition period, and the blood vessel imaging device can acquire a third echo image and a fourth echo image in a second repetition period. The second repetition period and the first repetition period are different signal acquisition periods, i.e., the third echo image and the fourth echo image are in different repetition periods from the first echo image and the second echo image. The third echo image and the fourth echo image both contain blood vessel information and non-blood vessel information, i.e., the third echo image and the fourth echo image are both bright blood signals of magnetic resonance.

[0079] The third echo image and the fourth echo image are both acquired after flow velocity compensation processing, and the proton signals with flow characteristics are retained, so that the third echo image and the fourth echo image both contain blood vessel information and non-blood vessel information.

[0080] The echo time of the first echo image is the same as the echo time of the third echo image, the echo time of the second echo image is the same as the echo time of the fourth echo image, and the echo time of the fourth echo image is less than the echo time of the third echo image. The first echo image and the second echo image are acquired at a first flip angle, and the third echo image and the fourth echo image are acquired at a second flip angle.

[0081] With reference to Figure 3 and Figure 5 The first echo image echo11 and the second echo image echo12 are in a first repetition period and are acquired at a first flip angle θ1, and the third echo image echo21 and the fourth echo image echo22 are in a second repetition period and are acquired at a second flip angle θ2.

[0082] With reference to Figure 5 In the same repetition period TR, the flip angle is the second flip angle θ2, and a flow compensation (FC) module is applied before the third echo image echo21 and the fourth echo image echo22 are acquired, respectively.

[0083] In the embodiment of the present application, the blood vessel imaging device can perform homodyne filtering processing on the phase image of the fourth echo image to obtain a generated susceptibility weighted mask, and then multiply the susceptibility weighted mask by the amplitude image of the fourth echo image to generate an SWI image.

[0084] Since biological tissues contain certain metal elements, such as iron and calcium ions in blood. Under the action of an external magnetic field, a certain local magnetic field will be formed inside the imaging tissue, which will produce a certain disturbance to the external magnetic field, thereby reflecting the susceptibility distribution characteristics of the biological tissue. The blood vessels of the biological tissue contain rich magnetic ions, so the distribution of blood vessels and pathological characteristics of the biological tissue can be extracted from the susceptibility information.

[0085] In another alternative implementation manner of the embodiment of the present application, the blood vessel imaging device can acquire a fifth echo image, and acquire a transverse relaxation image based on the fifth echo image and the first echo image.

[0086] The fifth echo image and the first echo image are in the same repetition period, the fifth echo image contains blood vessel information and non-blood vessel information, and the echo time of the fifth echo image is different from the echo time of the first echo image. Moreover, the echo time of the fifth echo image and the echo time of the first echo image are both less than the echo time of the second echo image. The echo time of the fifth echo image is less than the echo time of the first echo image, and the echo time of the first echo image is less than the echo time of the second echo image.

[0087] With reference to Figure 4Within the same repetition cycle TR, a flow compensation (FC) module is applied before the acquisition of the third echo image echo13.

[0088] In the embodiment of the present application, the blood vessel imaging device can perform homodyne filtering processing on the phase image of the first echo image to obtain a susceptibility weighted mask, and then multiply the susceptibility weighted mask by the magnitude image of the first echo image to generate the SWI image.

[0089] In the embodiment of the present application, the process of obtaining the transverse relaxation image by the blood vessel imaging device includes the following steps:

[0090] A1, determining a first ratio of a plurality of first magnitudes in the first target echo image to a plurality of second magnitudes in the second target echo image.

[0091] Wherein the first ratio Si of the ith first magnitude S11i to the ith second magnitude S12i can satisfy:

[0092] If the first target echo image includes the third echo image, the second target echo image includes the fourth echo image, and if the first target echo image includes the fifth echo image, the second target echo image includes the first echo image. The plurality of first magnitudes can be the magnitudes of a plurality of pixels in the magnitude image of the first target echo image. The plurality of second magnitudes can be the magnitudes of a plurality of pixels in the magnitude image of the second target echo image.

[0093] It can be understood that the number of the plurality of first magnitudes is the same as the number of the plurality of second magnitudes, and the plurality of first magnitudes and the plurality of second magnitudes correspond one by one.

[0094] A2, determining a time difference value of the echo time of the second target echo image and the echo time of the first target echo image.

[0095] The blood vessel imaging device can also determine a time difference value of the echo time of the second target echo image and the echo time of the first target echo image, wherein the time difference value ΔTE can satisfy: ΔTE = TE2 - TE1, wherein TE2 refers to the echo time of the second target echo image, and TE1 refers to the echo time of the first target echo image.

[0096] A3, for each first ratio, determining a transverse relaxation time of a pixel in the transverse relaxation image based on the first ratio and the time difference value.

[0097] After the blood vessel imaging device determines the first ratio of the plurality of first magnitudes to the plurality of second magnitudes and the time difference value, for each first ratio, the blood vessel imaging device can determine the transverse relaxation time of the pixel in the transverse relaxation image based on the first ratio and the time difference value, so as to obtain the transverse relaxation image (i.e. T2 *The transverse relaxation time is negatively correlated with the first ratio and positively correlated with the time difference, the transverse relaxation image includes blood vessel information and non-blood vessel information, and each pixel in the transverse relaxation image is one-to-one corresponding to each pixel in the amplitude image of the echo image.

[0098] Optionally, the transverse relaxation time T2*i of the ith pixel can satisfy:

[0099] Since the first target echo image and the second target echo image both include blood vessel information and non-blood vessel information, the transverse relaxation image determined based on the first target echo image and the second target echo image also includes blood vessel information and non-blood vessel information, and the transverse relaxation time of each pixel represents the transverse relaxation time of the blood vessel information and the non-blood vessel information of the pixel. For example, if the pixel is located in a brain region, the non-blood vessel information of the pixel can include gray matter, white matter, skull and other tissues.

[0100] In step 203, a time difference is determined, and a second ratio of the transverse relaxation time of each pixel.

[0101] After determining the transverse relaxation image, the blood vessel imaging device can determine a reference echo image with the same echo time as the second echo image based on the first echo image and the transverse relaxation image.

[0102] Optionally, the blood vessel imaging device can determine a time difference and a second ratio of the transverse relaxation time of each pixel.

[0103] In step 204, a plurality of fourth amplitudes of the reference echo image are determined based on a plurality of third amplitudes in the first echo image and the transverse relaxation time of the plurality of pixels.

[0104] The blood vessel imaging device can determine a plurality of fourth amplitudes of the reference echo image based on a plurality of third amplitudes in the first echo image and the transverse relaxation time of the plurality of pixels. Wherein the fourth amplitude is positively correlated with the third amplitude and the transverse relaxation time respectively.

[0105] Optionally, the ith fourth amplitude S22i can satisfy S21i is the ith third amplitude.

[0106] In the embodiments of the present application, the plurality of third amplitudes can be amplitudes of a plurality of pixels in an amplitude image of the first echo image, and the plurality of fourth amplitudes are amplitudes of a plurality of pixels in an amplitude image of the reference echo image.

[0107] As known from the principle of imaging by magnetic resonance gradient echo sequence, the amplitude of the magnetic resonance signal exponentially decays with the increase of echo time, and the degree of decay is related to the transverse relaxation time T2* of the imaged tissue. For example, the amplitude S12 of the fourth echo image and the amplitude S11 of the third echo image satisfy: The amplitudes of the first echo image and the fifth echo image, and the amplitudes of the second echo image and the first echo image all satisfy the formula.

[0108] Therefore, the reference echo image obtained by the first echo image and the transverse relaxation image in the embodiments of the present application has the same echo time as the second echo image, contains the blood vessel information and non-blood vessel information of the first echo image, and the difference between the amplitude of the non-blood vessel information in the reference echo image and the amplitude of the corresponding non-blood vessel information in the second echo image is less than the difference threshold.

[0109] It can be understood that in the case where the difference between the amplitude of the non-blood vessel information in the reference echo image and the amplitude of the corresponding non-blood vessel information in the second echo image is less than the difference threshold, the amplitude of the non-blood vessel information in the reference echo image is basically consistent with the amplitude of the corresponding non-blood vessel information in the second echo image.

[0110] Step 205, subtracting the reference echo image from the second echo image to obtain a target blood vessel image.

[0111] After determining the reference echo image, the blood vessel imaging device can subtract the reference echo image from the second echo image to obtain a target blood vessel image.

[0112] Since the difference between the amplitude of the non-blood vessel information in the reference echo image and the amplitude of the non-blood vessel information in the second echo image is less than the difference threshold, subtracting the reference echo image from the second echo image can obtain a blood vessel image in which the non-blood vessel information is completely suppressed.

[0113] In the embodiments of the present application, the blood vessel imaging device can subtract each fourth amplitude in the reference echo image from the corresponding fifth amplitude in the second echo image to obtain a target blood vessel image. The number of the plurality of fifth amplitudes is the same as the number of the plurality of fourth amplitudes, and the plurality of fifth amplitudes and the plurality of fourth amplitudes correspond one-to-one.

[0114] Figures 6 to 8 In order, the transverse relaxation image, the SWI and the target blood vessel image in the embodiments of the present application. From Figure 8 It can be seen that the non-blood vessel information of the target blood vessel image is completely suppressed, and the suppression degree of the signal in the brain skull region and the gray matter region is basically consistent.

[0115] Figure 9 And Figure 10The target vessel image obtained by using a maximum intensity projection (MIP) algorithm and a multi-planar reformatting (MPR) algorithm is shown in the target vessel image (a) of FIG. 1. Figure 8

[0116] Figure 9 In the target vessel image after MIP, the contrast of the blood vessels is clear, and the background is completely suppressed, and in particular, the brain skull region and the surrounding small blood vessels are clearly displayed. Figure 10 The target vessel image after MPR also has good blood vessel contrast and good background suppression effect.

[0117] According to the principle of magnetic resonance, the signal formula of the phase-encoding gradient echo sequence is as follows:

[0118]

[0119] Wherein, S represents the amplitude in the echo image, θ represents the flip angle of the pulse sequence, ρ represents the proton density, Tr represents the repetition time of the pulse sequence, T1 represents the longitudinal relaxation time, and TE represents the echo time.

[0120] The amplitude of the third echo image acquired at the first flip angle is denoted by S11, and the amplitude of the fourth echo image is denoted by S12, for example.

[0121] The amplitude S11 of the third echo image satisfies:

[0122] The amplitude S12 of the fourth echo image satisfies:

[0123] From the above two formulas, it can be deduced that the transverse relaxation time T2* satisfies: Thus, the formula satisfied by the transverse relaxation time T2*i of the i-th pixel can be obtained.

[0124] In summary, the embodiment of the present application provides a blood vessel imaging method. After the blood vessel imaging device acquires the first echo image, the second echo image and the transverse relaxation image, the reference echo image with the same echo time as the second echo image can be determined based on the first echo image and the transverse relaxation image, and the target vessel image can be obtained by subtracting the reference echo image from the second echo image. Since the reference echo image is determined based on the first echo image and the transverse relaxation image, the amplitude of the non-blood vessel information in the reference echo image is basically consistent with the amplitude of the non-blood vessel information in the second echo image. By subtracting the reference echo image from the second echo image, a blood vessel image with complete non-blood vessel information suppression can be obtained. ​

[0125] This application provides a computer-readable storage medium storing a vascular imaging program thereon, which, when executed by a processor, implements the vascular imaging method described above. For example, Figure 1 or Figure 2 The vascular imaging method shown.

[0126] Figure 11 This is a schematic diagram of the structure of a vascular imaging device provided in an embodiment of this application, as shown below. Figure 11 As shown, the system includes a memory 1101, a processor 1102, and a vascular imaging program stored in the memory 1101 and executable on the processor 1102. When the processor 1102 executes the vascular imaging program, it implements the vascular imaging method described in the above embodiments. For example, Figure 1 or Figure 2 The vascular imaging method shown.

[0127] Figure 12 This is a block diagram of a vascular imaging device provided in an embodiment of this application, such as... Figure 12 As shown, the device includes:

[0128] The signal acquisition module 1201 is used to acquire a first echo image and a second echo image with different echo times within the same repetition cycle. The first echo image contains vascular information and non-vascular information, and the second echo image contains non-vascular information.

[0129] The first image acquisition module 1202 is used to acquire a lateral relaxation image, which includes vascular information and non-vascular information.

[0130] The second image acquisition module 1203 is used to determine a reference echo image with the same echo time as the second echo image based on the first echo image and the transverse relaxation image, and subtract the reference echo image from the second echo image to obtain the target blood vessel image.

[0131] In summary, this application provides a vascular imaging device. After acquiring a first echo image, a second echo image, and a transverse relaxation image, the vascular imaging device can determine a reference echo image with the same echo time as the second echo image based on the first echo image and the transverse relaxation image. The target vascular image is obtained by subtracting the reference echo image from the second echo image. Since the reference echo image is determined based on the first echo image and the transverse relaxation image, the amplitude of non-vascular information in the reference echo image is essentially the same as the amplitude of non-vascular information in the second echo image. By subtracting the reference echo image from the second echo image, a vascular image with thoroughly suppressed non-vascular information can be obtained.

[0132] refer to Figure 13 The first image acquisition module 1202 is used for:

[0133] The first image acquisition sub-module 12021 is configured to acquire a third echo image and a fourth echo image which are in a same repetition period and have different echo times;

[0134] The second image acquisition sub-module 12022 is configured to acquire a transverse relaxation image based on the third echo image and the fourth echo image, the third echo image and the second echo image being in different repetition periods, and the third echo image and the fourth echo image both containing blood vessel information and non-blood vessel information.

[0135] Alternatively, the first image acquisition sub-module 12021 is configured to acquire a fifth echo image, the fifth echo image and the first echo image being in a same repetition period, the fifth echo image containing blood vessel information and non-blood vessel information, and an echo time of the fifth echo image being different from an echo time of the first echo image.

[0136] The second image acquisition sub-module 12022 is configured to acquire a transverse relaxation image based on the fifth echo image and the first echo image.

[0137] Optionally, the echo time of the fifth echo image and the echo time of the first echo image are both less than the echo time of the second echo image.

[0138] Optionally, the second image acquisition sub-module 12022 is configured to:

[0139] determine a first ratio of a plurality of first amplitudes of a first target echo image to a plurality of second amplitudes of a second target echo image;

[0140] determine a time difference value of an echo time of the second target echo image to an echo time of the first target echo image;

[0141] for each first ratio, determine a transverse relaxation time of a pixel in the transverse relaxation image based on the first ratio and the time difference value;

[0142] wherein, if the first target echo image comprises the third echo image, the second target echo image comprises the fourth echo image, if the first target echo image comprises the fifth echo image, the second target echo image comprises the first echo image, the transverse relaxation time is negatively correlated with the first ratio and positively correlated with the time difference value.

[0143] Optionally, the transverse relaxation time T2*i of the i-th pixel satisfies:

[0144] ΔTE is the time difference value, and Si is the i-th first ratio.

[0145] Optionally, the second image acquisition module 1203 is configured to:

[0146] determining, based on the first echo image and the transverse relaxation image, a reference echo image with the same echo time as the second echo image, comprising:

[0147] determining a time difference value with the second ratio of the transverse relaxation time of each pixel in the transverse relaxation image;

[0148] determining, based on the plurality of third amplitudes of the first echo image and the plurality of second ratios, a plurality of fourth amplitudes of the reference echo image;

[0149] wherein the fourth amplitude is positively correlated with the third amplitude and the second ratio.

[0150] Optionally, the ith fourth amplitude S22i satisfies:

[0151] S21i is the ith third amplitude, and T2*i is the transverse relaxation time of the ith pixel.

[0152] Optionally, the transverse relaxation time of each pixel in the transverse relaxation image indicates the transverse relaxation time of the blood vessel information and the non-blood vessel information of the pixel.

[0153] Optionally, the first echo image is obtained after flow velocity compensation, and the second echo image is obtained after flow velocity encoding.

[0154] In summary, the embodiment of the present application provides a blood vessel imaging device. After the blood vessel imaging device obtains the first echo image, the second echo image and the transverse relaxation image, the blood vessel imaging device can determine, based on the first echo image and the transverse relaxation image, a reference echo image with the same echo time as the second echo image, and obtain the target blood vessel image by subtracting the reference echo image from the second echo image. Since the reference echo image is determined based on the first echo image and the transverse relaxation image, the amplitude of the non-blood vessel information in the reference echo image is basically consistent with the amplitude of the non-blood vessel information in the second echo image. By subtracting the reference echo image from the second echo image, a blood vessel image with complete non-blood vessel information suppression can be obtained.

[0155] It is to be appreciated that the above description and the examples that follow are intended to be illustrative only and that changes can be made to the description and examples without departing from the scope of the application. Note also that the use of particular brand names in the description is solely for illustration and should not be construed as an endorsement of such brands.

[0156] It should be understood that aspects of the application can be implemented in hardware, software, firmware or a combination thereof. In the above embodiments, various steps or methods can be implemented in software or firmware that is stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any of the following technologies, known in the art, can be used: a hybrid of the above technologies, a combination of any of the above technologies, etc.

[0157] In the description of the application, reference has been made to the use of terms such as "optional", "some embodiments", "an example", "a specific example" or "some examples" mean that a particular feature, structure, material, or characteristic being described is included in at least one embodiment or example of the application. The illustrative appearances of the above-mentioned terms in various places in the specification are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0158] In addition, the terms "first", "second", and the like used in the embodiments of the present application are only used for descriptive purposes, and can not be understood as indicating or implying relative importance, or implicitly indicating the number of technical features indicated in the embodiments. Therefore, the features defined by the terms "first", "second", and the like in the embodiments of the present application can explicitly or implicitly indicate that at least one of the features is included in the embodiments. In the description of the present application, the meaning of the word "multiple" is at least two or two or more, such as two, three, four, etc., unless otherwise specifically limited in the embodiments.

[0159] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and can not be understood as limiting the present application, and those of ordinary skill in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A method of blood vessel imaging, characterized by, The method comprises: acquiring a first echo image and a second echo image with different echo times in a same repetition period, the first echo image containing blood vessel information and non-blood vessel information, and the second echo image containing the non-blood vessel information; acquiring a transverse relaxation image, the transverse relaxation image including the blood vessel information and the non-blood vessel information; determining a reference echo image with the same echo time as the second echo image based on the first echo image and the transverse relaxation image; subtracting the reference echo image from the second echo image to obtain a target blood vessel image.

2. The method of claim 1, wherein, The acquiring of the transverse relaxation image comprises: acquiring a third echo image and a fourth echo image with different echo times in a same repetition period, and acquiring the transverse relaxation image based on the third echo image and the fourth echo image, the third echo image being in a different repetition period from the second echo image, and the third echo image and the fourth echo image both containing the blood vessel information and the non-blood vessel information; or, acquiring a fifth echo image, and acquiring the transverse relaxation image based on the fifth echo image and the first echo image, the fifth echo image and the first echo image being in a same repetition period, the fifth echo image containing the blood vessel information and the non-blood vessel information, and the echo time of the fifth echo image being different from the echo time of the first echo image.

3. The method of claim 2, wherein, The echo time of the fifth echo image and the echo time of the first echo image are both less than the echo time of the second echo image.

4. The method of claim 2, wherein, The acquiring of the transverse relaxation image further comprises: determining a first ratio of a plurality of first amplitudes of a first target echo image to a plurality of second amplitudes of a second target echo image; determining a time difference value of the echo time of the second target echo image to the echo time of the first target echo image; for each of the first ratio, determining a transverse relaxation time of a pixel in the transverse relaxation image based on the first ratio and the time difference value; wherein, if the first target echo image includes the third echo image, the second target echo image includes the fourth echo image, if the first target echo image includes the fifth echo image, the second target echo image includes the first echo image, the transverse relaxation time is negatively correlated with the first ratio and positively correlated with the time difference value.

5. The method of claim 4, wherein, The transverse relaxation time T2*i of an i-th pixel satisfies: said AT E is a time difference value, said Si is an i-th said first ratio.

6. The method of claim 4, wherein, The determining of the reference echo image with the same echo time as the second echo image based on the first echo image and the transverse relaxation image comprises: determining a second ratio of the time difference value to the transverse relaxation time of each pixel in the transverse relaxation image; determining a plurality of fourth amplitudes of the reference echo image based on a plurality of third amplitudes of the first echo image and a plurality of the second ratio; wherein, the fourth amplitude is positively correlated with the third amplitude and the second ratio.

7. The method of claim 6, wherein, An i-th fourth amplitude S22i satisfies: S21i is the i-th third amplitude, and T2*i is the transverse relaxation time of the i-th pixel.

8. The method according to any one of claims 1 to 7, characterized in that, The transverse relaxation time of each pixel in the transverse relaxation image indicates the transverse relaxation time of the blood vessel information and the non-blood vessel information of the pixel.

9. The method according to any one of claims 1 to 7, characterized in that, The first echo image is acquired after flow velocity compensation, and the second echo image is acquired after flow velocity encoding.

10. A computer-readable storage medium, characterized in that, A computer readable storage medium having stored thereon a vascular imaging program, the vascular imaging program, when executed by a processor, implementing the vascular imaging method according to any one of claims 1 to 9.

11. A blood vessel imaging apparatus, characterized by comprising: A computer including a memory, a processor, and a vascular imaging program stored on the memory and executable on the processor, the processor implementing the vascular imaging method according to any one of claims 1 to 9 when executing the vascular imaging program.

12. A blood vessel imaging apparatus, characterized by comprising: The device comprises: a signal acquisition module configured to acquire a first echo image and a second echo image with different echo times in a same repetition period, the first echo image containing blood vessel information and non-blood vessel information, and the second echo image containing the non-blood vessel information; a first image acquisition module configured to acquire a transverse relaxation image, the transverse relaxation image including the blood vessel information and the non-blood vessel information; a second image acquisition module configured to determine a reference echo image with the same echo time as the second echo image based on the first echo image and the transverse relaxation image, and subtract the reference echo image from the second echo image to obtain a target blood vessel image.

Images