阅读说明：本技术 一种适用于人体肝脏脂肪核磁共振检测的单边磁体及核磁共振系统 (Single-sided magnet and nuclear magnetic resonance system suitable for human liver fat nuclear magnetic resonance detection ) 是由 陆荣生 张金翔 吴子岳 王伟谦 胡剑雄 于 2020-11-27 设计创作，主要内容包括：本发明涉及核磁共振技术领域,公开了一种适用于人体肝脏脂肪核磁共振检测的单边磁体及核磁共振系统,即通过将单边磁体设计为包括有由左上磁块、左下磁块、中央底部磁块、右下磁块和右上磁块依次相接触构成的U形主磁体结构,并使各磁块的充磁方向沿顺时针方向或逆时针方向依次设置,可一方面为目标区域提供足够大的磁感应强度,另一方面可改善磁场强度等势面/等势线的形状,使等势面/等势线避开人体皮下脂肪的位置,从而可减小来自皮下脂肪的核磁共振信号对来自肝脏脂肪的核磁共振信号所产生干扰影响。同时可使目标区域附近的磁场梯度为定值,而且梯度值较小,使得磁感应强度线性衰减,磁感应强度较高,均匀性较好,有利于测量。(The invention relates to the technical field of nuclear magnetic resonance, and discloses a single-side magnet and a nuclear magnetic resonance system suitable for detecting human liver fat nuclear magnetic resonance. Meanwhile, the magnetic field gradient near the target area is a fixed value, and the gradient value is small, so that the magnetic induction intensity is linearly attenuated, the magnetic induction intensity is high, the uniformity is good, and the measurement is facilitated.)

1. The single-sided magnet suitable for the human liver fat nuclear magnetic resonance detection is characterized by comprising a U-shaped main magnet structure formed by sequentially contacting an upper left magnet (1), a lower left magnet (2), a central bottom magnet (3), a lower right magnet (4) and an upper right magnet (5), wherein a U-shaped opening of the U-shaped main magnet structure is used for being inserted into the side part of a human body corresponding to the human liver;

the magnetizing direction of the upper left magnet (1), the magnetizing direction of the lower left magnet (2), the magnetizing direction of the central bottom magnet (3), the magnetizing direction of the lower right magnet (4) and the magnetizing direction of the upper right magnet (5) are sequentially arranged along the clockwise direction or the anticlockwise direction, wherein the magnetizing direction of the central bottom magnet (3) is horizontally arranged;

the upper left magnetic block (1) and the upper right magnetic block (5) are arranged in a bilateral symmetry mode and have the same material, shape and size, and the lower left magnetic block (2) and the lower right magnetic block (4) are arranged in a bilateral symmetry mode and have the same material, shape and size.

2. The single-sided magnet as defined in claim 1, wherein the upper left magnet (1) is a pentagonal magnetic steel having a vertical cross section consisting of an upper right trapezoid and a lower rectangle, the lower left magnet (2) is a first rectangular magnetic steel having a vertical cross section consisting of a rectangle, the central bottom magnet (3) is a second rectangular magnetic steel having a horizontal cross section consisting of a rectangle, wherein the top side of the upper right trapezoid is shorter than the bottom side and the oblique side is located on the right side, and the bottom surface of the upper left magnet (1) is in contact with the top surface of the lower left magnet (2) and has the same shape and size.

3. The single-sided magnet as claimed in claim 2, wherein the bottom surface of the lower left magnet block (2), the bottom surface of the central bottom magnet block (3) and the bottom surface of the lower right magnet block (4) are flush, and the top surface of the central bottom magnet block (3) is lower than the top surface of the lower left magnet block (2) and the top surface of the lower right magnet block (4), respectively, so that a space for mounting a radio frequency coil and a coil fixing device can be enclosed among the lower left magnet block (2), the central bottom magnet block (3) and the lower right magnet block (4).

4. The single-sided magnet as claimed in claim 2, wherein the central region of the top surface of the central bottom magnetic block (3) is provided with a through hole (301) for vibration test of the whole structure.

5. The single-sided magnet as claimed in claim 1, wherein the magnetizing direction of the upper left magnet (1) and the magnetizing direction of the upper right magnet (5) are respectively parallel to the vertical direction, the magnetizing direction of the lower left magnet (2) and the magnetizing direction of the lower right magnet (4) respectively form an included angle with the vertical direction, and the included angle is 40-50 degrees.

6. The single-sided magnet as claimed in claim 1, wherein the magnetizing direction of the upper left magnet (1) and the magnetizing direction of the upper right magnet (5) are not parallel to the vertical direction, the magnetizing direction of the lower left magnet (2) and the magnetizing direction of the lower right magnet (4) are arranged in bilateral symmetry with the vertical direction at an included angle, and are larger than or smaller than X degrees, wherein X is 40-50.

7. The single-sided magnet of claim 1, wherein the U-shaped main magnet structure is made of a permanent magnet material.

8. The single-sided magnet as claimed in claim 1, further comprising a U-shaped assembly housing structure formed by sequentially connecting a left-side top cover (601), a left-side holding plate (602), a base (603), a right-side holding plate (604), and a right-side top cover (605);

the base (603) is used for fixing the central bottom magnetic block (3) and the whole U-shaped main magnet structure, the left clamping plate (602) is fixed on the left side of the top surface of the base (603) through screws and is used for clamping and fixing the left lower magnetic block (2) and the left upper magnetic block (1), the right clamping plate (604) is fixed on the right side of the top surface of the base (603) through screws and is used for clamping and fixing the right lower magnetic block (4) and the right upper magnetic block (5), the left side top cover (601) is fixed on the upper part of the left side clamping plate (602) through screws and is used for covering and fixing the left upper magnetic block (1) and the left lower magnetic block (2), the right side top cover (605) is fixed on the upper part of the right side clamping plate (604) through screws and is used for covering and fixing the upper right magnetic block (5) and the lower right magnetic block (4).

9. The single-sided magnet of claim 8, wherein the U-shaped mounting shell structure is made of a non-magnetic material.

10. A nuclear magnetic resonance system is characterized by comprising a man-machine interaction device, an electronic control cabinet, a radio frequency coil and the single-sided magnet which is applicable to the nuclear magnetic resonance detection of the fat of the liver of a human body according to any one of claims 1 to 9;

the radio frequency coil is arranged at the bottom of the U-shaped opening of the unilateral magnet and used for transmitting a radio frequency excitation signal of a nuclear magnetic resonance measurement sequence and receiving a nuclear magnetic resonance signal under the control of the electronic control cabinet;

the electronic control cabinet is electrically connected with the radio frequency coil and is used for controlling the radio frequency coil to emit a radio frequency excitation signal of a nuclear magnetic resonance measurement sequence and analyzing the received nuclear magnetic resonance signal to obtain an analysis result;

and the human-computer interaction equipment is in communication connection with the electronic control cabinet and is used for displaying the analysis result.

Technical Field

The invention belongs to the technical field of nuclear magnetic resonance, relates to the fields of electromagnetism, medical diagnosis, screening and the like, and particularly relates to a single-sided magnet and a nuclear magnetic resonance system suitable for detecting fat in human liver by nuclear magnetic resonance.

Background

With the change of living habits, the incidence of fatty liver diseases is increasing year by year. The latest statistical results show that more than one fourth of adults worldwide have fatty liver, the prevalence rate of the fatty liver in China is as high as 27%, the onset age of the disease tends to be younger, and the number of the fatty liver of children is increasing. In patients with obesity, metabolic syndrome, type 2 diabetes, and prolonged excessive alcohol consumption, the prevalence of fatty liver is as high as 50% or more. Therefore, the method has important social value for preventing and treating the fatty liver. Currently, fatty liver examination mainly includes laboratory examination, Imaging examination, and liver biopsy pathology examination, and the Imaging examination includes real-time ultrasound (B-ultrasound), Computed Tomography (CT), Magnetic Resonance Imaging (MRI), and vibration-controlled transient elastography (VCTE). Laboratory examination mainly plays a role in auxiliary diagnosis and analysis assistance, liver biopsy pathology examination is invasive examination with injuries, and in imaging examination, MRI is higher in soft tissue resolution than CT examination, and the detection rate of early small liver cancer is higher. Proton density fat content determination based on MRI (MRI-PDFF) is a gold standard for noninvasive quantitative assessment of liver fat content and sensitive diagnosis of mild fatty liver, while real-time elastography (MRE) based on MRI quantitatively assesses liver fibrosis by elasticity values, and is not affected by obesity and ascites.

The nuclear magnetic resonance is used as a non-contact detection means, and has good application prospects in the aspects of biological detection, organic chemistry and medicine and pharmacology. The nuclear magnetic resonance system consists of the following parts: the magnetic resonance system comprises a magnet part, a coil part for transmitting and receiving signals and an electronic control part for signal analysis, wherein the performance of the magnet part directly determines the performance of the nuclear magnetic resonance system, so that the performance of the magnet is important. Compared with a superconducting magnet and an electromagnet, the permanent magnet type magnet has low requirement on the working environment, does not need to provide extra energy consumption, has the advantages of simple structure, low cost, convenience for miniaturization and the like, and is widely applied to the field of low and medium field nuclear magnetic resonance. For human body examination, the magnet needs to be placed on one side of the human body, so that the traditional closed permanent magnet structure cannot be adopted, and a unilateral open type magnet structure needs to be adopted.

However, when the existing single-side open magnet structure is used for nuclear magnetic resonance detection of human liver fat, the generated magnetic field equipotential surface can not effectively avoid human subcutaneous fat, so that nuclear magnetic resonance signals from the subcutaneous fat can generate interference influence on the nuclear magnetic resonance signals from the liver fat. Therefore, the research on the novel unilateral open magnet suitable for the nuclear magnetic resonance detection of the human liver fat has extremely important scientific research significance and social significance.

Disclosure of Invention

The invention aims to solve the problem that the existing unilateral open magnet structure is easily interfered by subcutaneous fat nuclear magnetic resonance signals when used for detecting the human liver fat nuclear magnetic resonance, and provides a novel unilateral magnet and a nuclear magnetic resonance system which are suitable for detecting the human liver fat nuclear magnetic resonance.

The technical scheme adopted by the first aspect of the invention is as follows:

a single-side magnet suitable for human liver fat nuclear magnetic resonance detection comprises a U-shaped main magnet structure formed by sequentially contacting an upper left magnet, a lower left magnet, a central bottom magnet, a lower right magnet and an upper right magnet, wherein a U-shaped opening of the U-shaped main magnet structure is used for being inserted into a human body side part corresponding to a human liver;

the magnetizing direction of the upper left magnetic block, the magnetizing direction of the lower left magnetic block, the magnetizing direction of the central bottom magnetic block, the magnetizing direction of the lower right magnetic block and the magnetizing direction of the upper right magnetic block are sequentially arranged along the clockwise direction or the anticlockwise direction, wherein the magnetizing direction of the central bottom magnetic block is horizontally arranged;

the upper left magnetic block and the upper right magnetic block are arranged in a bilateral symmetry mode and have the same material, shape and size, and the lower left magnetic block and the lower right magnetic block are arranged in a bilateral symmetry mode and have the same material, shape and size.

Based on the content of the invention, the single-sided magnet structure suitable for the nuclear magnetic resonance detection of the human liver fat is provided, namely, the single-sided magnet is designed to comprise a U-shaped main magnet structure formed by sequentially contacting a left upper magnet block, a left lower magnet block, a central bottom magnet block, a right lower magnet block and a right upper magnet block, and the magnetizing directions of the magnet blocks are sequentially arranged along the clockwise direction or the anticlockwise direction, so that on one hand, enough magnetic induction intensity can be provided for a target area, on the other hand, the shape of an equipotential surface/equipotential line of the magnetic field intensity can be improved, the equipotential surface/equipotential line is enabled to avoid the position of the human subcutaneous fat, and the interference influence of nuclear magnetic resonance signals from the subcutaneous fat on the nuclear magnetic resonance signals from the liver fat can be reduced. Meanwhile, the magnetic field gradient near the target area is a fixed value, the gradient value is small, the magnetic induction intensity is linearly attenuated, the magnetic induction intensity is high, the uniformity is good, the signal-to-noise ratio of measurement can be improved, and the measurement is facilitated. In addition, the U-shaped opening of the unilateral magnet structure can be attached to the geometric shape of the side face of a human body, so that the comfort is improved, the measurement is convenient, the overall structure has the advantages of light weight, small size and the like, and the portable measurement can be possible.

Preferably, the upper left magnetic block is pentagonal magnetic steel formed by an upper right trapezoid and a lower rectangle in a vertical section, the lower left magnetic block is rectangular first rectangular magnetic steel in the vertical section, the central bottom magnetic block is rectangular second rectangular magnetic steel in a horizontal section, the top edge of the upper right trapezoid is shorter than the bottom edge, the bevel edge of the upper right trapezoid is located on the right side, and the bottom surface of the upper left magnetic block is in contact with the top surface of the lower left magnetic block and has the same shape and size.

Preferably, the bottom surfaces of the left lower magnetic block, the central bottom magnetic block and the right lower magnetic block are flush, and the top surface of the central bottom magnetic block is lower than the top surfaces of the left lower magnetic block and the right lower magnetic block, so that a space for mounting a radio frequency coil and a coil fixing device can be enclosed among the left lower magnetic block, the central bottom magnetic block and the right lower magnetic block.

Preferably, the center area of the top surface of the central bottom magnetic block is provided with a through hole for carrying out vibration test of the whole structure.

Preferably, the magnetizing direction of the upper left magnetic block and the magnetizing direction of the upper right magnetic block are respectively parallel to the vertical direction, an included angle exists between the magnetizing direction of the lower left magnetic block and the magnetizing direction of the lower right magnetic block and the vertical direction, and the included angle is 40-50 degrees.

Optimally, the magnetizing direction of the upper left magnetic block and the magnetizing direction of the upper right magnetic block are not parallel to the vertical direction, the magnetizing direction of the lower left magnetic block and the magnetizing direction of the lower right magnetic block are arranged in bilateral symmetry with the vertical direction respectively and are larger than X degrees or smaller than X degrees, and X is a value between 40 and 50.

Preferably, the U-shaped main magnet structure is made of a permanent magnet material.

The optimized U-shaped assembly shell structure also comprises a U-shaped assembly shell structure formed by sequentially connecting a left top cover, a left clamping plate, a base, a right clamping plate and a right top cover;

the base is used for fixing bottom magnetic path of central authorities and whole U-shaped main magnet structure, the left side grip block passes through the fix with screw the top surface left side of base is used for the centre gripping to fix down the magnetic path on a left side with the magnetic path on a left side, the right side grip block passes through the fix with screw the top surface right side of base is used for the centre gripping to fix down the magnetic path on a right side with the magnetic path on a right side, the left side top cap passes through the fix with screw the upper portion of left side grip block just is used for covering fixedly the magnetic path on a left side with the magnetic path on a left side, the right side top cap passes through the fix with screw the upper portion of right side grip block just is.

Preferably, the U-shaped assembly shell structure is made of a non-magnetic material.

The second aspect of the invention adopts the technical scheme that:

a nuclear magnetic resonance system comprises human-computer interaction equipment, an electronic control cabinet, a radio frequency coil and a single-side magnet which is described in the first aspect and is suitable for detecting the nuclear magnetic resonance of the fat of the liver of a human body;

the radio frequency coil is arranged at the bottom of the U-shaped opening of the unilateral magnet and used for transmitting a radio frequency excitation signal of a nuclear magnetic resonance measurement sequence and receiving a nuclear magnetic resonance signal under the control of the electronic control cabinet;

the electronic control cabinet is electrically connected with the radio frequency coil and is used for controlling the radio frequency coil to emit a radio frequency excitation signal of a nuclear magnetic resonance measurement sequence and analyzing the received nuclear magnetic resonance signal to obtain an analysis result;

the human-computer interaction equipment is in communication connection with the electronic control cabinet and is used for displaying the analysis result

The invention has the beneficial effects that:

(1) the invention provides a single-side magnet structure and a nuclear magnetic resonance system suitable for detecting the nuclear magnetic resonance of the fat of the human liver, namely, the single-side magnet is designed into a U-shaped main magnet structure which is formed by sequentially contacting a left upper magnet block, a left lower magnet block, a central bottom magnet block, a right lower magnet block and a right upper magnet block, and the magnetizing directions of the magnet blocks are sequentially arranged along the clockwise direction or the anticlockwise direction, so that on one hand, enough magnetic induction intensity is provided for a target area, on the other hand, the shape of an equipotential surface/equipotential line of the magnetic field intensity can be improved, and the equipotential surface/equipotential line is enabled to avoid the position of the subcutaneous fat of the human body, thereby reducing the interference influence of nuclear magnetic resonance signals from the subcutaneous fat on the nuclear magnetic resonance signals from the fat of;

(2) the magnetic field gradient near the target area can be a fixed value, the gradient value is small, the magnetic induction intensity is linearly attenuated, the magnetic induction intensity is high, the uniformity is good, the signal-to-noise ratio of measurement can be improved, and the measurement is facilitated;

(3) the U-shaped opening of the unilateral magnet structure can be fitted with the geometric shape of the side face of a human body, so that the comfort is improved, the measurement is convenient, the overall structure has the advantages of light weight, small size and the like, and the portable measurement becomes possible;

(4) through U-shaped assembly shell structure, can fix the encapsulation U-shaped main magnet structure, ensure the steadiness of U-shaped main magnet structure in the use.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic perspective view of a U-shaped main magnet in a single-sided magnet according to the present invention.

Fig. 2 is a schematic view of the magnetization direction of the U-shaped main magnet in the single-sided magnet provided by the present invention.

Fig. 3 is a schematic view of an assembly structure of the U-shaped main magnet and the U-shaped assembling housing in the single-sided magnet according to the present invention.

Fig. 4 is a schematic diagram of a disassembled structure of the U-shaped assembly shell in the unilateral magnet provided by the invention.

FIG. 5 is an exemplary diagram of the shape of the equipotential lines of the magnetic field in the YOZ plane during a magnetic resonance examination using a single-sided magnet according to the present invention.

FIG. 6 is an exemplary diagram of the shape of the equipotential lines of the magnetic field in the XOZ plane during magnetic resonance examination using a single-sided magnet according to the present invention.

FIG. 7 is an exemplary graph of the constant gradient attenuation of magnetic induction near a target region during NMR examination using a single-sided magnet.

FIG. 8 is an exemplary illustration of an embodiment of a magnetic resonance system according to the present invention.

In the above drawings: 1-an upper left magnet; 2-a lower left magnetic block; 3-a central bottom magnet; 301-a through hole; 4-lower right magnetic block; 5-upper right magnetic block; 601-left side top cover; 602-left clamping plate; 603-a base; 604-right clamping plate; 605-right side cap.

Detailed Description

The invention is further described with reference to the following figures and specific embodiments. It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. Specific structural and functional details disclosed herein are merely illustrative of example embodiments of the invention. This invention may, however, be embodied in many alternate forms and should not be construed as limited to the embodiments set forth herein.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments of the present invention.

It should be understood that, for the term "and/or" as may appear herein, it is merely an associative relationship that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, B exists alone, and A and B exist at the same time; for the term "/and" as may appear herein, which describes another associative object relationship, it means that two relationships may exist, e.g., a/and B, may mean: a exists independently, and A and B exist independently; in addition, for the character "/" that may appear herein, it generally means that the former and latter associated objects are in an "or" relationship.

It will be understood that when an element is referred to herein as being "connected," "connected," or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may be present. Conversely, if a unit is referred to herein as being "directly connected" or "directly coupled" to another unit, it is intended that no intervening units are present. In addition, other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between … …" versus "directly between … …", "adjacent" versus "directly adjacent", etc.).

It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises," "comprising," "includes" and/or "including," when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, elements, components, and/or groups thereof.

It should also be noted that, in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may, in fact, be executed substantially concurrently, or the figures may sometimes be executed in the reverse order, depending upon the functionality/acts involved.

It should be understood that specific details are provided in the following description to facilitate a thorough understanding of example embodiments. However, it will be understood by those of ordinary skill in the art that the example embodiments may be practiced without these specific details. For example, systems may be shown in block diagrams in order not to obscure the examples in unnecessary detail. In other instances, well-known processes, structures and techniques may be shown without unnecessary detail in order to avoid obscuring example embodiments.

Example one

As shown in fig. 1-2, the single-sided magnet suitable for human liver fat nmr detection provided in this embodiment includes a U-shaped main magnet structure formed by sequentially contacting an upper left magnet 1, a lower left magnet 2, a central bottom magnet 3, a lower right magnet 4, and an upper right magnet 5, wherein a U-shaped opening of the U-shaped main magnet structure is used for inserting into a side of a human body corresponding to a human liver; the magnetizing direction of the upper left magnet 1, the magnetizing direction of the lower left magnet 2, the magnetizing direction of the central bottom magnet 3, the magnetizing direction of the lower right magnet 4 and the magnetizing direction of the upper right magnet 5 are sequentially arranged along a clockwise direction or an anticlockwise direction, wherein the magnetizing direction of the central bottom magnet 3 is horizontally arranged; the upper left magnetic block 1 and the upper right magnetic block 5 are arranged in a bilateral symmetry mode and have the same material, shape and size, and the lower left magnetic block 2 and the lower right magnetic block 4 are arranged in a bilateral symmetry mode and have the same material, shape and size.

As shown in fig. 1 and 2, in the specific structure of the unilateral magnet, when the unilateral open magnet structure is used for the mri of the fat of the human liver, the unilateral open magnet structure is placed at the right underarm part of the patient (i.e. the side part of the human body corresponding to the human liver), and the patient lifts the right arm upwards to leave a test space for the magnet part, so that the unilateral magnet is designed into a U-shaped main magnet structure, the side part of the human body can be placed in the U-shaped opening during the test, and the side surface of the human body can be tightly attached to the upper surface of the rf coil located in the middle of the bottom of the U-shaped opening, thereby maximally utilizing the space. As shown in fig. 2, the magnetizing direction of the upper left magnet block 1 (i.e. the magnetizing direction indicated by the arrow, the same below), the magnetizing direction of the lower left magnet block 2, the magnetizing direction of the central bottom magnet block 3, the magnetizing direction of the lower right magnet block 4 and the magnetizing direction of the upper right magnet block 5 are sequentially connected end to end along the clockwise direction, wherein, because the sizes of the upper left magnetic block 1, the lower left magnetic block 2, the lower right magnetic block 4 and the upper right magnetic block 5 are larger, can provide enough magnetic induction intensity for a target area, and the central bottom magnetic block 3 is relatively flat, it can improve the shape of the equipotential surface/equipotential line of the magnetic field intensity by the wider size on the horizontal plane, so that the equipotential surface/equipotential line avoids the position of subcutaneous fat of the human body, therefore, the interference effect of the nuclear magnetic resonance signal from the subcutaneous fat on the nuclear magnetic resonance signal from the liver fat can be reduced. As shown in fig. 5, when the single-sided magnet is used for magnetic resonance examination, the shape of the equipotential lines of the magnetic field in the YOZ plane is good, the equipotential lines at the middle are higher than the target area, the middle is concave, the two sides are convex, focusing is good, and the equipotential lines at the two sides are far away from the center, so that the equipotential lines at the two sides avoid the human body and subcutaneous fat, and the nuclear magnetic resonance signals of the liver fat cannot be interfered. As shown in fig. 6, when the single-sided magnet is used for magnetic resonance examination, the shape of the equipotential lines of the magnetic field in the XOZ plane is good, that is, the equipotential lines in the XOZ plane are bell-shaped, the upper portion is narrow, a target region can be better focused, the bottom portion is wide, the distance from the coil is far, subcutaneous fat of a human body can be avoided, and the interference influence of subcutaneous fat nuclear magnetic resonance signals on liver fat nuclear magnetic resonance signals is reduced. In addition, as shown in fig. 7, the gradient of the magnetic field near the target region is a fixed value, and the gradient value is small, so that the magnetic induction intensity is linearly attenuated, the uniformity is good, and the linearity is high.

Therefore, through the detailed structural description of the single-side magnet, the single-side magnet structure suitable for the nuclear magnetic resonance detection of the human liver fat is provided, namely, the single-side magnet is designed into a U-shaped main magnet structure formed by sequentially contacting an upper left magnet block, a lower left magnet block, a central bottom magnet block, a lower right magnet block and an upper right magnet block, and the magnetizing directions of the magnet blocks are sequentially arranged along the clockwise direction or the anticlockwise direction, so that on one hand, enough magnetic induction intensity can be provided for a target area, on the other hand, the shape of an equipotential surface/equipotential line of the magnetic field intensity can be improved, the equipotential surface/equipotential line is enabled to be away from the position of the human subcutaneous fat, and therefore the interference influence of nuclear magnetic resonance signals from the subcutaneous fat on the nuclear magnetic resonance signals from the liver fat can. Meanwhile, the magnetic field gradient near the target area is a fixed value, the gradient value is small, the magnetic induction intensity is linearly attenuated, the magnetic induction intensity is high, the uniformity is good, the signal-to-noise ratio of measurement can be improved, and the measurement is facilitated. In addition, the U-shaped opening of the unilateral magnet structure can be attached to the geometric shape of the side face of a human body, so that the comfort is improved, the measurement is convenient, the overall structure has the advantages of light weight, small size and the like, and the portable measurement can be possible.

Preferably, the upper left magnetic block 1 is pentagonal magnetic steel formed by an upper right trapezoid and a lower rectangle in vertical section, the lower left magnetic block 2 is rectangular first rectangular magnetic steel in vertical section, the central bottom magnetic block 3 is rectangular second rectangular magnetic steel in horizontal section, wherein the top edge of the upper right trapezoid is shorter than the bottom edge and the bevel edge is located on the right side, and the bottom surface of the upper left magnetic block 1 is in contact with the top surface of the lower left magnetic block 2 and has the same shape and size. Because the upper left magnetic block 1 and the upper right magnetic block 5 are arranged in bilateral symmetry, the top edge of an upper right trapezoid in the upper right magnetic block 5 is shorter than the bottom edge and the bevel edge is positioned on the left side, so that the whole U-shaped main magnet structure is in a wide U shape, the bevel edge of the U-shaped side can be attached to the side of the human body, and the measurement comfort is further improved. Preferably, a through hole 301 for performing a vibration test of the whole structure is formed in the central area of the top surface of the central bottom magnetic block 3.

Preferably, the bottom surfaces of the left lower magnetic block 2, the central bottom magnetic block 3 and the right lower magnetic block 4 are flush, and the top surface of the central bottom magnetic block 3 is lower than the top surfaces of the left lower magnetic block 2 and the right lower magnetic block 4, so that a space for installing a radio frequency coil and a coil fixing device can be enclosed among the left lower magnetic block 2, the central bottom magnetic block 3 and the right lower magnetic block 4. As shown in fig. 2, since a space for placing the rf coil and the coil fixing device is left in the middle of the bottom of the U-shaped opening of the U-shaped main magnet structure, the interference of the main magnet and the assembly housing to the magnetic field of the rf coil can be reduced, i.e., if the left space is too small, the rf coil will be tightly attached to the assembly housing, and the assembly housing will interfere with the measurement signal generated by the coil, thereby affecting the overall performance of the nmr system, so the space reserved for the rf coil in the middle is large enough, and deep enough in the depth direction. In addition, when detecting, the human side can go to the bottom flush with trapezoidal in the pentagonal magnet steel (be that upper left magnetic block 1 and upper right magnetic block 5) down, and the while is close to coil upper surface, can further practice thrift usage space, improves travelling comfort and convenience.

Preferably, the magnetizing direction of the upper left magnetic block 1 and the magnetizing direction of the upper right magnetic block 5 are respectively parallel to the vertical direction, the magnetizing direction of the lower left magnetic block 2 and the magnetizing direction of the lower right magnetic block 4 respectively form an included angle with the vertical direction, and the included angle is 40-50 degrees. As shown by solid arrows in fig. 2, the magnetizing directions of the upper left magnetic block 1 and the right magnetic block 5 are opposite, and because the magnetizing directions of the lower left magnetic block 2 and the right magnetic block 4 respectively form an angle of exactly 45 degrees with the vertical direction, the distribution shapes of the field intensity, the gradient and the magnetic field equipotential surface/equipotential line of the target area can be optimized at the angle.

Optimally, the magnetizing direction of the upper left magnetic block 1 and the magnetizing direction of the upper right magnetic block 5 can also be not parallel to the vertical direction respectively, at the moment, the magnetizing directions of the lower left magnetic block 2 and the right magnetic block 4 are arranged in bilateral symmetry with the vertical direction respectively, and are larger than X degrees or smaller than X degrees at the same time, wherein X takes a value between 40 and 50. As shown by a dotted arrow in fig. 2, for example, X is 45, when the magnetizing direction of the upper left magnetic block 1 and the magnetizing direction of the upper right magnetic block 5 are biased outward, the magnetic field strength of the target area decreases, and the magnetic field gradient decreases; when the magnetizing directions of the upper left magnetic block 1 and the right magnetic block 5 are inwards deviated, the magnetic field intensity of a target area is increased, and the magnetic field gradient is increased.

Preferably, the U-shaped main magnet structure is made of a permanent magnet material, such as, but not limited to, rubidium, iron, boron, samarium, cobalt, aluminum, nickel, cobalt, and the like.

Preferably, the device also comprises a U-shaped assembly shell structure formed by sequentially connecting a left top cover 601, a left clamping plate 602, a base 603, a right clamping plate 604 and a right top cover 605; the base 603 is used to fix the central bottom magnetic block 3 and the entire U-shaped main magnet structure, the left clamping plate 602 is fixed on the left side of the top surface of the base 603 through screws and is used for clamping and fixing the left lower magnetic block 2 and the left upper magnetic block 1, the right clamping plate 604 is fixed on the right side of the top surface of the base 603 through screws and is used for clamping and fixing the right lower magnetic block 4 and the right upper magnetic block 5, the left side top cover 601 is fixed on the upper part of the left side clamping plate 602 by a screw and is used for covering and fixing the left upper magnetic block 1 and the left lower magnetic block 2 (namely, by the clamping action of the left side top cover 601 and the base 603), the right top cover 605 is fixed on the upper portion of the right clamping plate 604 by screws and is used for covering and fixing the upper right magnetic block 5 and the lower right magnetic block 4 (i.e. by the clamping action of the right top cover 605 and the base 603). As shown in fig. 3 and 4, the U-shaped main magnet structure can be fixedly enclosed by the U-shaped assembly housing structure, ensuring the stability of the U-shaped main magnet structure during use. Preferably, the U-shaped assembly housing is made of a non-magnetic material, such as 6061 aluminum alloy subjected to oxidation treatment, but not limited to the above materials, so that the force strength of the assembly housing is sufficient to bear the magnetic force between the magnetic steels.

In summary, the single-sided magnet provided by the present embodiment has the following technical effects:

(1) the embodiment provides a single-side magnet structure suitable for human liver fat nuclear magnetic resonance detection, namely, the single-side magnet is designed to comprise a U-shaped main magnet structure formed by sequentially contacting an upper left magnet block, a lower left magnet block, a central bottom magnet block, a lower right magnet block and an upper right magnet block, and the magnetizing directions of the magnet blocks are sequentially arranged along the clockwise direction or the anticlockwise direction, so that on one hand, enough magnetic induction intensity is provided for a target area, on the other hand, the shape of an equipotential surface/equipotential line of the magnetic field intensity can be improved, and the equipotential surface/equipotential line is enabled to avoid the position of human subcutaneous fat, thereby reducing the interference influence of nuclear magnetic resonance signals from the subcutaneous fat on nuclear magnetic resonance signals from the liver fat;

(2) the magnetic field gradient near the target area can be a fixed value, the gradient value is small, the magnetic induction intensity is linearly attenuated, the magnetic induction intensity is high, the uniformity is good, the signal-to-noise ratio of measurement can be improved, and the measurement is facilitated;

(3) the U-shaped opening of the unilateral magnet structure can be fitted with the geometric shape of the side face of a human body, so that the comfort is improved, the measurement is convenient, the overall structure has the advantages of light weight, small size and the like, and the portable measurement becomes possible;

(4) through U-shaped assembly shell structure, can fix the encapsulation U-shaped main magnet structure, ensure the steadiness of U-shaped main magnet structure in the use.

Example two

The embodiment provides a nuclear magnetic resonance system using the single-sided magnet on the basis of the technical scheme of the single-sided magnet in the first embodiment, and the nuclear magnetic resonance system comprises human-computer interaction equipment, an electronic control cabinet, a radio frequency coil and the single-sided magnet which is described in the first embodiment and is suitable for detecting the nuclear magnetic resonance of the fat of the liver of a human body; the radio frequency coil is arranged at the bottom of the U-shaped opening of the unilateral magnet and used for transmitting a radio frequency excitation signal of a nuclear magnetic resonance measurement sequence and receiving a nuclear magnetic resonance signal under the control of the electronic control cabinet; the electronic control cabinet is electrically connected with the radio frequency coil and is used for controlling the radio frequency coil to emit a radio frequency excitation signal of a nuclear magnetic resonance measurement sequence and analyzing the received nuclear magnetic resonance signal to obtain an analysis result; and the human-computer interaction equipment is in communication connection with the electronic control cabinet and is used for displaying the analysis result.

As shown in fig. 8, the human-computer interaction device may be, but is not limited to, a computer device with a keyboard, a mouse, and a display, and the magnetic resonance principle of the electronic control cabinet and the radio frequency coil is the prior art, so that the technical effect of this embodiment can be directly derived from the embodiment, and is not described herein again.

The various embodiments described above are merely illustrative, and may or may not be physically separate, as they relate to elements illustrated as separate components; if reference is made to a component displayed as a unit, it may or may not be a physical unit, and may be located in one place or distributed over a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: modifications of the technical solutions described in the embodiments or equivalent replacements of some technical features may still be made. And such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Finally, it should be noted that the present invention is not limited to the above alternative embodiments, and that various other forms of products can be obtained by anyone in light of the present invention. The above detailed description should not be taken as limiting the scope of the invention, which is defined in the claims, and which the description is intended to be interpreted accordingly.