CN115956898B - Magnetic resonance imaging method, system and terminal capable of effectively inhibiting blood flow signals - Google Patents
Magnetic resonance imaging method, system and terminal capable of effectively inhibiting blood flow signals Download PDFInfo
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Abstract
The invention discloses a magnetic resonance imaging method capable of effectively inhibiting blood flow signals, which is applied to magnetic resonance imaging equipment and comprises the following steps: when the time for injecting the blood pool contrast agent into the object to be scanned reaches the preset image scanning time, transmitting a pulse sequence to the object to be scanned through a blood flow signal suppression module so as to suppress the blood flow signal of the object to be scanned; calculating the inversion time of the blood pool contrast agent; when the pulse sequence transmitting time length reaches the inversion time, acquiring a magnetic resonance signal of the suppressed blood flow signal through an image acquisition module; based on the acquired magnetic resonance signals, a magnetic resonance image is generated. The blood pool contrast agent is injected into the object to be scanned, and the calculated contrast agent inversion time is combined to acquire the magnetic resonance signals of the blood flow signals to be restrained, so that the restraint effect of the blood flow signals is controlled only with time and is not influenced by the blood flow velocity and the blood flow direction, and the image quality of the magnetic resonance imaging is improved.
Description
Technical Field
The invention relates to the technical field of image processing and digital medical treatment, in particular to a magnetic resonance imaging method, a system and a terminal capable of effectively inhibiting blood flow signals.
Background
In magnetic resonance nerve root imaging, cardiac black blood magnetic resonance imaging and magnetic resonance blood vessel wall imaging, the inhibition intensity and uniformity of flowing blood signals are key factors influencing the image quality. In the imaging system, the more complete the blood flow signal is inhibited, the more the contrast between nerve roots, cardiac muscles, blood vessel wall tissues and adjacent tissues can be enhanced, so that the better the image quality is. The double-reverse-magnetization recovery preparation pulse is a common blood flow signal suppression technique, but the suppression effect is greatly affected by the blood flow speed and direction. Since the systolic and diastolic periods of the heart and the period of the blood vessel of the scanned object are not uniform, there is caused a large heterogeneity in the flow velocity and direction of blood in the heart and the blood vessel, in which a blood flow signal having a relatively fast flow velocity is easily completely suppressed, but a slow blood flow signal is difficult to suppress completely. In the T2 weighted nerve root imaging, due to the relaxation characteristics of nerve tissue and blood and similar morphological shape, the blood signal slowly flowing in the vena cava accompanied by peripheral nerves is difficult to be inhibited, and the structural misjudgment is easily caused; in cardiac black blood magnetic resonance imaging and magnetic resonance vascular wall imaging, slow blood flow signals are also easily mistaken for thrombus or tumor tissue, resulting in false positive results.
Therefore, the search for a magnetic resonance blood flow signal suppression method which is not influenced by the blood flow speed and direction is important to improve the effects of magnetic resonance nerve root imaging, cardiac black blood magnetic resonance imaging and magnetic resonance blood vessel wall imaging.
Disclosure of Invention
The embodiment of the application provides a magnetic resonance imaging method, a system and a terminal capable of effectively inhibiting blood flow signals. The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosed embodiments. This summary is not an extensive overview and is intended to neither identify key/critical elements nor delineate the scope of such embodiments. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.
In a first aspect, an embodiment of the present application provides a magnetic resonance imaging method capable of effectively suppressing a blood flow signal, which is applied to a magnetic resonance imaging apparatus, where the magnetic resonance imaging apparatus includes a blood flow signal suppression module and an image acquisition module, and the method includes:
when the time for injecting the blood pool contrast agent into the object to be scanned reaches the preset image scanning time, transmitting a pulse to the object to be scanned through the blood flow signal suppression module so as to suppress the blood flow signal of the object to be scanned;
calculating the inversion time of the blood pool contrast agent;
when the pulse sequence transmitting time length reaches the inversion time, acquiring a magnetic resonance signal of the suppressed blood flow signal through an image acquisition module;
based on the acquired magnetic resonance signals, a magnetic resonance image of the object to be scanned is generated.
Optionally, the pulse sequence includes a double inversion recovery sequence and a short-time inversion recovery sequence;
transmitting a pulse sequence to a subject to be scanned to suppress a blood flow signal of the subject to be scanned, comprising:
transmitting double-inversion recovery pulse to the object to be scanned so as to inhibit the heart and great vessel black blood imaging blood flow signals of the object to be scanned;
a short-time inversion recovery pulse is transmitted to the subject to be scanned to suppress fat signals and blood flow signals imaged by nerve roots of the subject to be scanned.
Optionally, calculating the inversion time of the blood pool contrast agent includes:
acquiring a first longitudinal relaxation time of intravascular blood without injection of a blood pool contrast agent;
determining the injection concentration of the blood pool contrast agent according to the relaxation efficiency of the blood pool agent;
calculating a second longitudinal relaxation time after the blood pool contrast agent is injected according to the first longitudinal relaxation time, the relaxation efficiency and the injection concentration;
the inversion time of the blood pool contrast agent is calculated from the second longitudinal relaxation time.
Optionally, the second longitudinal relaxation time is calculated according to the formula:
the method comprises the steps of carrying out a first treatment on the surface of the Wherein (1)>
For the second longitudinal relaxation time, +.>
For the first longitudinal relaxation time, +.>
For relaxation efficiency, +.>
Is the injection concentration.
Optionally, the inversion time of the blood pool contrast agent is calculated as:
the method comprises the steps of carrying out a first treatment on the surface of the Wherein,,
for reversal time of blood pool contrast agent, +.>
For the second longitudinal relaxation time ln represents the logarithm of the base e, ++>
For the time interval of two transmit pulses, said +.>
Greater than the optimal echo time after injection of the blood pool contrast agent.
Optionally, the generating of the magnetic resonance image of the object to be scanned is participated in based on the acquired magnetic resonance signals, comprising:
filling the acquired magnetic resonance signals into a K space; wherein,,
the K space is a Fourier space, and the Fourier space is a filling space of original data of the magnetic resonance equipment signal with space positioning coding information;
obtaining K space image data after all tissue layers of an object to be scanned are completely scanned;
and carrying out image reconstruction on the K space image data to obtain a magnetic resonance image of the object to be scanned.
Optionally, image reconstruction is performed on the K-space image data to obtain a magnetic resonance image of the object to be scanned, including:
performing Fourier transform on the K space image data to decode space positioning coding information in the K space image data to obtain MR image data with different signal intensities;
MR image data with different signal intensities are distributed to the corresponding pixel space positions, so that a magnetic resonance image of an object to be scanned is obtained.
In a second aspect, embodiments of the present application provide a magnetic resonance imaging system effective to suppress blood flow signals, the system comprising:
the blood flow signal suppression module is used for transmitting pulses to the object to be scanned through the blood flow signal suppression module when the time for the object to be scanned to inject the blood pool contrast agent reaches the preset image scanning time so as to suppress blood flow signals of the object to be scanned;
the inversion time calculation module is used for calculating the inversion time of the blood pool contrast agent;
the magnetic resonance signal acquisition module is used for acquiring magnetic resonance signals of the suppressed blood flow signals through the image acquisition module when the pulse sequence transmitting duration reaches the inversion time;
the magnetic resonance image generation module is used for participating in generating a magnetic resonance image of the object to be scanned based on the acquired magnetic resonance signals.
In a third aspect, embodiments of the present application provide a terminal, which may include: a processor and a memory; wherein the memory stores a computer program adapted to be loaded by the processor and to perform the method steps described above.
The technical scheme provided by the embodiment of the application can comprise the following beneficial effects:
in the embodiment of the application, a magnetic resonance imaging system capable of effectively inhibiting blood flow signals firstly transmits a pulse sequence to an object to be scanned through a blood flow signal inhibition module when the time for injecting blood pool contrast agent into the object to be scanned is monitored to reach the preset image scanning time, so as to inhibit the blood flow signals of the object to be scanned, then calculates the inversion time of the blood pool contrast agent, secondly acquires magnetic resonance signals of the inhibited blood flow signals through an image acquisition module when the pulse sequence transmission time reaches the inversion time, and finally participates in generating magnetic resonance images based on the acquired magnetic resonance signals. The blood pool contrast agent is injected into the object to be scanned, and the calculated contrast agent inversion time is combined to acquire the magnetic resonance signals of the blood flow signals to be restrained, so that the restraint effect of the blood flow signals is controlled only with time and is not influenced by the blood flow velocity and the blood flow direction, and the image quality of the magnetic resonance imaging is improved.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.
Fig. 1 is a schematic flow chart of a magnetic resonance imaging method capable of effectively suppressing a blood flow signal according to an embodiment of the present application;
FIG. 2 is a schematic diagram of a magnetic resonance imaging system capable of effectively suppressing blood flow signals according to an embodiment of the present application;
fig. 3 is a schematic structural diagram of a terminal according to an embodiment of the present application.
Detailed Description
The following description and the drawings sufficiently illustrate specific embodiments of the invention to enable those skilled in the art to practice them.
It should be understood that the described embodiments are merely some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The implementations described in the following exemplary examples do not represent all implementations consistent with the invention. Rather, they are merely examples of systems and methods that are consistent with aspects of the invention as detailed in the accompanying claims.
In the description of the present invention, it should be understood that the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art. Furthermore, in the description of the present invention, unless otherwise indicated, "a plurality" means two or more. "and/or", describes an association relationship of an association object, and indicates that there may be three relationships, for example, a and/or B, and may indicate: a exists alone, A and B exist together, and B exists alone. The character "/" generally indicates that the context-dependent object is an "or" relationship.
The application provides a magnetic resonance imaging method, a system, a storage medium and a terminal capable of effectively inhibiting blood flow signals, so as to solve the problems in the related technical problems. In the technical scheme provided by the application, the blood pool contrast agent is injected into the object to be scanned, and the calculated contrast agent inversion time is combined to acquire the magnetic resonance signals of the blood flow signals to be restrained, so that the restraint effect of the blood flow signals is only controlled along with time and is not influenced by the blood flow velocity and the blood flow direction, the image quality of the magnetic resonance imaging is improved, and the method and the device are described in detail by adopting the exemplary embodiment.
The following describes in detail a magnetic resonance imaging method capable of effectively suppressing a blood flow signal according to an embodiment of the present application with reference to fig. 1. The method can be implemented by means of a computer program and can be operated on a magnetic resonance imaging system based on a von neumann system, and can effectively inhibit blood flow signals. The computer program may be integrated in the application or may run as a stand-alone tool class application.
Referring to fig. 1, a flow chart of a magnetic resonance imaging method capable of effectively suppressing a blood flow signal is provided for an embodiment of the present application, and the flow chart is applied to a magnetic resonance imaging device, where the magnetic resonance imaging device includes a blood flow signal suppression module and an image acquisition module. As shown in fig. 1, the method of the embodiment of the present application may include the following steps:
s101, when the time length of the blood pool contrast agent injected into the object to be scanned reaches the preset image scanning time length, transmitting a pulse sequence to the object to be scanned through a blood flow signal suppression module so as to suppress the blood flow signal of the object to be scanned;
wherein the object to be scanned is a tissue on a target for which magnetic resonance imaging is desired, such as the heart of a user. The blood pool contrast agent can be super-small superparamagnetism nano ferric oxide, and is subjected to 3.0T field intensity of the magnetic resonance imaging equipmentr 1 Relaxation efficiency of 9.5s -1 mM -1 ，r 2 Relaxation efficiency of 74.8s -1 mM -1 . The pulse sequence may be any pulse sequence for implementing black blood technique, such as a double inversion recovery sequence(DIR) short-time inversion recovery Sequence (STIR).
In the embodiment of the application, when a pulse sequence is transmitted to an object to be scanned to inhibit a blood flow signal of the object to be scanned, a double-inversion recovery sequence is transmitted to the object to be scanned to inhibit a blood flow signal of black blood imaging of hearts and great vessels of the object to be scanned, or a short-time inversion recovery sequence is transmitted to the object to be scanned to inhibit a fat signal and a blood flow signal of nerve roots imaging of the object to be scanned.
In one possible implementation, the method is based on blood pool contrast agent firstr 1 Relaxation efficiencyr 2 Relaxation efficiency and related usage regulations, set the concentration of blood pool contrast agent
And injection amount->
And injection speed +.>
Intravenous injection of blood pool contrast agent, such as super-small superparamagnetic nano ferric oxide, into the scanned object according to the above parameters, and then setting of scanning time point after blood pool contrast agent injection>
,
Greater than or equal to the blood pool plasma distribution equilibrium time and less than or equal to the blood pool plasma half-life, in this example,/->
More than or equal to 5 minutes after the blood pool contrast agent is injected, and less than or equal to 15 hours after the blood pool contrast agent is injected; finally, when the time period for monitoring the injection of the blood pool contrast agent into the object to be scanned reaches the preset image scanning time period, transmitting a series of radio frequency pulses to the object to be scanned through the blood flow signal suppression module, wherein the radio frequency pulses comprise but are not limited to 180 DEG selective or non-selective inverseThe pulse is turned over and pre-saturated to suppress the blood flow signal of the object to be scanned.
Further, a fat saturation pulse may be additionally applied to the scan subject while suppressing the fat signal.
S102, calculating the inversion time of the blood pool contrast agent;
in the embodiment of the application, when the inversion time of the blood pool contrast agent is calculated, first the first longitudinal relaxation time of blood in a blood vessel when the blood pool contrast agent is not injected is obtained, then the injection concentration of the blood pool contrast agent is determined according to the relaxation efficiency of the blood pool agent, then the second longitudinal relaxation time after the blood pool contrast agent is injected is calculated according to the first longitudinal relaxation time, the relaxation efficiency and the injection concentration, and finally the inversion time of the blood pool contrast agent is calculated according to the second longitudinal relaxation time.
Specifically, the calculation formula of the second longitudinal relaxation time is:
the method comprises the steps of carrying out a first treatment on the surface of the Wherein (1)>
For the second longitudinal relaxation time, +.>
For the first longitudinal relaxation time, +.>
For relaxation efficiency, +.>
Is the injection concentration. />
Specifically, the inversion time calculation formula of the blood pool contrast agent is as follows:
the method comprises the steps of carrying out a first treatment on the surface of the Wherein,,
for reversal time of blood pool contrast agent, +.>
For the second longitudinal relaxation time ln represents the logarithm of the base e, ++>
For the time interval of two transmit pulses, said +.>
Greater than the optimal echo time after injection of the blood pool contrast agent.
Specifically, after applying the blood flow signal suppression module to a certain layer in the tissue of the object to be scanned, the patient can wait for reaching the inversion time
The longitudinal magnetization vectors of the liquid in the blood pool of each flow direction and flow speed in a certain layer of the tissue of the object to be scanned are zero crossing points, and at the moment, the image acquisition module can be applied to the object to be scanned for signal acquisition. Wherein, because the blood pool contrast agent exists in the blood pool stably, the blood pool contrast agent does not permeate into the gaps around the tissues, the blood pool contrast agent is added with the blood pool contrast agent>
Longitudinal relaxation time of intravascular fluid after injection of blood pool>
And (5) determining. Thus can be according to +.>
Calculate->
。
Specifically, the time interval between two transmitted pulses
It is necessary to be greater than the optimal echo time after injection of blood pool agent +.>
And all tissue relaxation is recovered, so that mutual interference of adjacent tissue proton phase saturation is avoided; in this embodiment, <' > a->
89-169 ms;
Depending on the tissue relaxation properties of nerves, muscles, vessel walls, blood pools and fat, when the T2-STIR-FSE sequence is adopted for magnetic resonance nerve root imaging, under the FSE acquisition module, the system is subjected to +.>
And (3) applying fat inhibition pulse to enable fat to longitudinally relax through 0 point under the condition of adopting blood pool agent for 60-80 ms, and meanwhile, enabling the difference between blood pool signals and nerve tissue signals to be maximum so as to obtain optimal nerve-blood pool comparison and collecting nerve root reading signals under the optimal blood flow inhibition state. When T2 weighted half Fourier single excitation fast spin echo (HASTE) sequence is adopted to image the black blood of the great cardiac blood vessel, under the HASTE module,
for 57ms, magnetic resonance signals are acquired in the optimal blood flow suppression state of the scan layer. Adopts the STIR module to allow for->
250 to 255ms, but is not limited to the above-mentioned optimum value.
S103, when the pulse sequence transmitting time length reaches the inversion time, acquiring a magnetic resonance signal of the suppressed blood flow signal through an image acquisition module;
in the embodiment of the application, when the pulse sequence transmitting time length reaches the inversion time, the image acquisition module acquires the magnetic resonance signals of the suppressed blood flow signals. The image acquisition module adopts a spin echo Sequence (SE) which can be a fast spin echo sequence (FSE), a variable flip angle fast spin echo Sequence (SPACE) or a single excitation fast spin echo sequence (HASTE, SS-FSE, SSH-TSE).
S104, participating in generating a magnetic resonance image of the object to be scanned based on the acquired magnetic resonance signals.
In the embodiment of the application, when the generation of the magnetic resonance image of the object to be scanned is participated based on the acquired magnetic resonance signals, firstly, the acquired magnetic resonance signals are filled into a K space; the method comprises the steps of obtaining K space image data after all tissue layers of an object to be scanned are completely scanned, and finally carrying out image reconstruction on the K space image data to obtain a magnetic resonance image of the object to be scanned.
Wherein the object to be scanned can be seen as a cube, which is composed of multiple layers of tissue layers.
In one possible implementation, after all tissue layers are scanned, acquiring signals and filling the signals into a K space to obtain K space image data; illustratively, when the magnetic resonance apparatus uses a T2-STIR-FSE sequence for magnetic resonance nerve root imaging at a field strength of 3.0T, it is ensured that, with all tissue relaxation recovery including blood after injection of blood pool agent,
3000 ms; when T2-HASTE is used for cardiac black blood imaging, the method comprises the following steps of>
1 to 4s, but is not limited to the above-mentioned optimum value. Using prior art techniques for image reconstruction of K-space data, the best implementation techniques may employ, but are not limited to, parallel acquisition (GRAPPA) or parallel reconstruction algorithm (SENSE).
For example, when image reconstruction is performed on K-space image data to obtain a magnetic resonance image of an object to be scanned, fourier transformation is performed on the K-space image data to decode spatial positioning coding information in the K-space image data to obtain MR image data with different signal intensities, and then the MR image data with different signal intensities are distributed to pixel space positions corresponding to the MR image data to obtain the magnetic resonance image of the object to be scanned.
In the embodiment of the application, a magnetic resonance imaging system capable of effectively inhibiting blood flow signals firstly transmits a pulse sequence to an object to be scanned through a blood flow signal inhibition module when the time for injecting blood pool contrast agent into the object to be scanned is monitored to reach the preset image scanning time, so as to inhibit the blood flow signals of the object to be scanned, then calculates the inversion time of the blood pool contrast agent, secondly acquires magnetic resonance signals of the inhibited blood flow signals through an image acquisition module when the pulse sequence transmission time reaches the inversion time, and finally participates in generating magnetic resonance images based on the acquired magnetic resonance signals. The blood pool contrast agent is injected into the object to be scanned, and the calculated contrast agent inversion time is combined to acquire the magnetic resonance signals of the blood flow signals to be restrained, so that the restraint effect of the blood flow signals is controlled only with time and is not influenced by the blood flow velocity and the blood flow direction, and the image quality of the magnetic resonance imaging is improved.
The following are system embodiments of the present invention that may be used to perform method embodiments of the present invention. For details not disclosed in the system embodiments of the present invention, please refer to the method embodiments of the present invention.
Referring to fig. 2, a schematic diagram of a magnetic resonance imaging system capable of effectively suppressing blood flow signals according to an exemplary embodiment of the present invention is shown. The magnetic resonance imaging system that is effective in suppressing blood flow signals may be implemented as all or part of the terminal by software, hardware, or a combination of both. The system 1 comprises a blood flow signal suppression module 10, an inversion time calculation module 20, a magnetic resonance signal acquisition module 30 and a magnetic resonance image generation module 40.
The blood flow signal suppression module 10 is configured to transmit a pulse sequence to the object to be scanned through the blood flow signal suppression module when it is monitored that the time length of injecting the blood pool contrast agent into the object to be scanned reaches a preset image scanning time length, so as to suppress a blood flow signal of the object to be scanned;
a reversal time calculation module 20 for calculating a reversal time of the blood pool contrast agent;
a magnetic resonance signal acquisition module 30 for acquiring a magnetic resonance signal of the suppressed blood flow signal by the image acquisition module when the pulse sequence transmission duration reaches the inversion time;
a magnetic resonance image generation module 40 for participating in generating a magnetic resonance image of the object to be scanned based on the acquired magnetic resonance signals.
It should be noted that, when the magnetic resonance imaging system capable of effectively suppressing the blood flow signal provided in the above embodiment performs the magnetic resonance imaging method capable of effectively suppressing the blood flow signal, only the division of the above functional modules is used for illustration, and in practical application, the above functional allocation may be performed by different functional modules according to needs, that is, the internal structure of the apparatus is divided into different functional modules, so as to complete all or part of the functions described above. In addition, the magnetic resonance imaging system capable of effectively suppressing the blood flow signal and the magnetic resonance imaging method capable of effectively suppressing the blood flow signal provided in the above embodiments belong to the same concept, and detailed implementation processes of the embodiments are shown in the method embodiments, which are not described herein.
The foregoing embodiment numbers of the present application are merely for describing, and do not represent advantages or disadvantages of the embodiments.
In the embodiment of the application, a magnetic resonance imaging system capable of effectively inhibiting blood flow signals firstly transmits a pulse sequence to an object to be scanned through a blood flow signal inhibition module when the time for injecting blood pool contrast agent into the object to be scanned is monitored to reach the preset image scanning time, so as to inhibit the blood flow signals of the object to be scanned, then calculates the inversion time of the blood pool contrast agent, secondly acquires magnetic resonance signals of the inhibited blood flow signals through an image acquisition module when the pulse sequence transmission time reaches the inversion time, and finally participates in generating magnetic resonance images based on the acquired magnetic resonance signals. The blood pool contrast agent is injected into the object to be scanned, and the calculated contrast agent inversion time is combined to acquire the magnetic resonance signals of the blood flow signals to be restrained, so that the restraint effect of the blood flow signals is controlled only with time and is not influenced by the blood flow velocity and the blood flow direction, and the image quality of the magnetic resonance imaging is improved.
The present invention also provides a computer readable medium having stored thereon program instructions which, when executed by a processor, implement a magnetic resonance imaging method for effectively suppressing blood flow signals provided by the above-described method embodiments.
The invention also provides a computer program product comprising instructions which, when run on a computer, cause the computer to perform the magnetic resonance imaging method of the above-described method embodiments which is effective in suppressing blood flow signals.
Referring to fig. 3, a schematic structural diagram of a terminal is provided in an embodiment of the present application. As shown in fig. 3, terminal 1000 can include: at least one processor 1001, at least one network interface 1004, a user interface 1003, a memory 1005, at least one communication bus 1002.
Wherein the communication bus 1002 is used to enable connected communication between these components.
The user interface 1003 may include a Display screen (Display) and a Camera (Camera), and the optional user interface 1003 may further include a standard wired interface and a wireless interface.
The network interface 1004 may optionally include a standard wired interface, a wireless interface (e.g., WI-FI interface), among others.
Wherein the processor 1001 may include one or more processing cores. The processor 1001 connects various parts within the overall electronic device 1000 using various interfaces and lines, performs various functions of the electronic device 1000 and processes data by executing or executing instructions, programs, code sets, or instruction sets stored in the memory 1005, and invoking data stored in the memory 1005. Alternatively, the processor 1001 may be implemented in at least one hardware form of digital signal processing (Digital Signal Processing, DSP), field programmable gate array (Field-Programmable Gate Array, FPGA), programmable logic array (Programmable Logic Array, PLA). The processor 1001 may integrate one or a combination of several of a central processing unit (Central Processing Unit, CPU), an image processor (Graphics Processing Unit, GPU), and a modem, etc. The CPU mainly processes an operating system, a user interface, an application program and the like; the GPU is used for rendering and drawing the content required to be displayed by the display screen; the modem is used to handle wireless communications. It will be appreciated that the modem may not be integrated into the processor 1001 and may be implemented by a single chip.
The memory 1005 may include a random access memory (RandomAccess Memory, RAM) or a Read-only memory (Read-only memory). Optionally, the memory 1005 includes a non-transitory computer readable medium (non-transitory computer-readable storage medium). The memory 1005 may be used to store instructions, programs, code, sets of codes, or sets of instructions. The memory 1005 may include a stored program area and a stored data area, wherein the stored program area may store instructions for implementing an operating system, instructions for at least one function (such as a touch function, a sound playing function, an image playing function, etc.), instructions for implementing the above-described respective method embodiments, etc.; the storage data area may store data or the like referred to in the above respective method embodiments. The memory 1005 may also optionally be at least one storage system located remotely from the processor 1001. As shown in fig. 3, an operating system, a network communication module, a user interface module, and a magnetic resonance imaging application that is effective to suppress blood flow signals may be included in a memory 1005, which is a type of computer storage medium.
In terminal 1000 shown in fig. 3, user interface 1003 is mainly used for providing an input interface for a user, and acquiring data input by the user; and the processor 1001 may be configured to invoke a magnetic resonance imaging application stored in the memory 1005 that is effective to suppress blood flow signals, and specifically perform the following operations:
when the time for injecting the blood pool contrast agent into the object to be scanned reaches the preset image scanning time, transmitting a pulse sequence to the object to be scanned through a blood flow signal suppression module so as to suppress the blood flow signal of the object to be scanned;
calculating the inversion time of the blood pool contrast agent;
when the pulse sequence transmitting time length reaches the inversion time, acquiring a magnetic resonance signal of the suppressed blood flow signal through an image acquisition module;
based on the acquired magnetic resonance signals, a magnetic resonance image of the object to be scanned is generated.
In one embodiment, the processor 1001, when executing the transmission pulse sequence to the object to be scanned to suppress the blood flow signal of the object to be scanned, specifically performs the following operations:
transmitting a double-inversion recovery sequence to the object to be scanned so as to inhibit the heart and great vessel black blood imaging blood flow signals of the object to be scanned;
a short-time reversal recovery sequence is transmitted to the scanned subject to suppress fat signals and nerve root imaged blood flow signals of the subject to be scanned.
In one embodiment, the processor 1001, when performing the calculation of the inversion time of the blood pool contrast agent, specifically performs the following operations:
acquiring a first longitudinal relaxation time of intravascular blood without injection of a blood pool contrast agent;
determining the injection concentration of the blood pool contrast agent according to the relaxation efficiency of the blood pool agent;
calculating a second longitudinal relaxation time after the blood pool contrast agent is injected according to the first longitudinal relaxation time, the relaxation efficiency and the injection concentration;
the inversion time of the blood pool contrast agent is calculated from the second longitudinal relaxation time.
In one embodiment, the processor 1001, when executing the generation of a magnetic resonance image of the object to be scanned based on the acquired magnetic resonance signals, specifically performs the following operations:
filling the acquired magnetic resonance signals into a K space; wherein,,
the K space is a Fourier space, and the Fourier space is a filling space of original data of the magnetic resonance equipment signal with space positioning coding information;
obtaining K space image data after all tissue layers of an object to be scanned are completely scanned;
and carrying out image reconstruction on the K space image data to obtain a magnetic resonance image of the object to be scanned.
In one embodiment, the processor 1001, when performing image reconstruction of K-space image data to obtain a magnetic resonance image of an object to be scanned, specifically performs the following operations:
performing Fourier transform on the K space image data to decode space positioning coding information in the K space image data to obtain MR image data with different signal intensities;
MR image data with different signal intensities are distributed to the corresponding pixel space positions, so that a magnetic resonance image of an object to be scanned is obtained.
In the embodiment of the application, a magnetic resonance imaging system capable of effectively inhibiting blood flow signals firstly transmits a pulse sequence to an object to be scanned through a blood flow signal inhibition module when the time for injecting blood pool contrast agent into the object to be scanned is monitored to reach the preset image scanning time, so as to inhibit the blood flow signals of the object to be scanned, then calculates the inversion time of the blood pool contrast agent, secondly acquires magnetic resonance signals of the inhibited blood flow signals through an image acquisition module when the pulse sequence transmission time reaches the inversion time, and finally participates in generating magnetic resonance images based on the acquired magnetic resonance signals. The blood pool contrast agent is injected into the object to be scanned, and the calculated contrast agent inversion time is combined to acquire the magnetic resonance signals of the blood flow signals to be restrained, so that the restraint effect of the blood flow signals is controlled only with time and is not influenced by the blood flow velocity and the blood flow direction, and the image quality of the magnetic resonance imaging is improved.
Those skilled in the art will appreciate that implementing all or part of the above-described methods in the embodiments may be accomplished by computer programs to instruct related hardware, and that the program for effectively suppressing magnetic resonance imaging of blood flow signals may be stored in a computer readable storage medium, which when executed may include the steps of the embodiments of the methods described above. The storage medium of the magnetic resonance imaging program capable of effectively inhibiting the blood flow signal can be a magnetic disk, an optical disk, a read-only memory, a random access memory or the like.
The foregoing disclosure is only illustrative of the preferred embodiments of the present application and is not intended to limit the scope of the claims herein, as the equivalent of the claims herein shall be construed to fall within the scope of the claims herein.
Claims (8)
1. A magnetic resonance imaging method capable of effectively suppressing blood flow signals, which is applied to a magnetic resonance imaging device, and is characterized in that the magnetic resonance imaging device comprises a blood flow signal suppression module and an image acquisition module, and the method comprises the following steps:
when the time for injecting the blood pool contrast agent into the object to be scanned is monitored to reach the preset image scanning time, transmitting a pulse sequence to the object to be scanned through the blood flow signal suppression module so as to suppress the blood flow signal of the object to be scanned;
calculating the inversion time of the blood pool contrast agent; wherein,,
the calculating the inversion time of the blood pool contrast agent comprises:
acquiring a first longitudinal relaxation time of intravascular blood without injection of a blood pool contrast agent;
determining the injection concentration of the blood pool contrast agent according to the relaxation efficiency of the blood pool agent;
calculating a second longitudinal relaxation time after the blood pool contrast agent is injected according to the first longitudinal relaxation time, the relaxation efficiency and the injection concentration;
calculating a reversal time of the blood pool contrast agent from the second longitudinal relaxation time;
when the pulse sequence transmitting time length reaches the inversion time, acquiring a magnetic resonance signal of the suppressed blood flow signal through the image acquisition module;
and based on the acquired magnetic resonance signals, participating in generating a magnetic resonance image of the object to be scanned.
2. The method of claim 1, wherein the pulse sequence comprises a double inversion recovery sequence and a short inversion recovery sequence;
the transmitting a pulse sequence to the object to be scanned to inhibit the blood flow signal of the object to be scanned comprises:
transmitting a double-inversion recovery sequence to the object to be scanned so as to inhibit the heart and great vessel black blood imaging blood flow signals of the object to be scanned;
a short-time reversal recovery sequence is transmitted to the scanned object to suppress fat signals and nerve root imaged blood flow signals of the object to be scanned.
3. The method of claim 1, wherein the second longitudinal relaxation time is calculated as:
the method comprises the steps of carrying out a first treatment on the surface of the Wherein (1)>
For the second longitudinal relaxation time, +.>
For the first longitudinal relaxation time, +.>
For relaxation efficiency, +.>
Is the injection concentration.
4. The method of claim 1, wherein the inversion time of the blood pool contrast agent is calculated as:
the method comprises the steps of carrying out a first treatment on the surface of the Wherein (1)>
For reversal time of blood pool contrast agent, +.>
For the second longitudinal relaxation time ln represents the logarithm of the base e, ++>
For the time interval of two transmit pulses, said +.>
Greater than the optimal echo time after injection of the blood pool contrast agent.
5. The method according to claim 1, wherein the participating in generating the magnetic resonance image of the object to be scanned based on the acquired magnetic resonance signals comprises:
filling the acquired magnetic resonance signals into a K space; wherein,,
the K space is a Fourier space, and the Fourier space is a filling space of original data of magnetic resonance equipment signals with space positioning coding information;
obtaining K space image data after all tissue layers of the object to be scanned are completely scanned;
and carrying out image reconstruction on the K space image data to obtain a magnetic resonance image of the object to be scanned.
6. The method of claim 5, wherein performing image reconstruction on the K-space image data to obtain a magnetic resonance image of the object to be scanned comprises:
performing Fourier transform on the K space image data to decode space positioning coding information in the K space image data to obtain MR image data with different signal intensities;
MR image data with different signal intensities are distributed to the corresponding pixel space positions, so that a magnetic resonance image of an object to be scanned is obtained.
7. A magnetic resonance imaging system capable of effectively suppressing blood flow signals, which is applied to a magnetic resonance imaging device, characterized in that the magnetic resonance imaging device comprises a blood flow signal suppression module and an image acquisition module, the system comprises:
the blood flow signal suppression module is used for transmitting a pulse sequence to the object to be scanned through the blood flow signal suppression module when the time for detecting the injection of the blood pool contrast agent to the object to be scanned reaches the preset image scanning time so as to suppress the blood flow signal of the object to be scanned;
the inversion time calculation module is used for calculating the inversion time of the blood pool contrast agent; wherein,,
the inversion time calculation module is specifically configured to:
acquiring a first longitudinal relaxation time of intravascular blood without injection of a blood pool contrast agent;
determining the injection concentration of the blood pool contrast agent according to the relaxation efficiency of the blood pool agent;
calculating a second longitudinal relaxation time after the blood pool contrast agent is injected according to the first longitudinal relaxation time, the relaxation efficiency and the injection concentration;
calculating a reversal time of the blood pool contrast agent from the second longitudinal relaxation time;
the magnetic resonance signal acquisition module is used for acquiring magnetic resonance signals of the suppressed blood flow signals through the image acquisition module when the pulse sequence transmitting time length reaches the inversion time;
and the magnetic resonance image generation module is used for participating in generating the magnetic resonance image of the object to be scanned based on the acquired magnetic resonance signals.
8. A terminal, comprising: a processor and a memory; wherein the memory stores a computer program adapted to be loaded by the processor and to perform the method according to any of claims 1-6.
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