CN115079071A - Magnetic resonance apparatus and control method thereof - Google Patents

Abstract

The invention relates to a magnetic resonance apparatus comprising: a superconducting magnet having a magnet bore with a main coil therein capable of producing a homogeneous region having at least two scanning fields of view within the magnet bore; at least two gradient coils disposed in the magnet bore along an axial direction; and at least two radio frequency coils which are arranged in the magnet hole along the axial direction and respectively correspond to the at least two radio frequency coils. The superconducting magnet generates the uniform area with at least two scanning visual fields to match with the at least two radio frequency coils, so that the at least two scanning visual fields can respectively correspond to a plurality of imaging parts, the simultaneous scanning of the plurality of imaging parts is realized, or the one-time scanning of a larger imaging part is realized, the scanning speed and efficiency are improved, and the use is convenient.

Description

Magnetic resonance apparatus and control method thereof

Technical Field

The invention relates to the technical field of medical imaging equipment, in particular to magnetic resonance equipment and a control method thereof.

Background

Conventional nmr medical devices typically employ superconducting magnets to generate a steady background magnetic field in a space. For example, a superconducting magnet with a field strength of 0.35T to 7.0T can generally generate a steady magnetic field region with a considerable volume near the geometric center of the superconducting magnet, i.e., a region of interest for scanning imaging. The Z-direction (i.e., axial to the cylindrical magnet) magnetic field in this region is very uniform. In the constant magnetic field area, the gradient coil is matched to generate a gradient field and a radio frequency field generated by a corresponding radio frequency coil (comprising a transmitting coil and a receiving coil), and the components can scan and image the corresponding tissue part of a scanning object in the area under the control of the magnetic resonance controller.

In order to meet the requirements of scanning imaging of a magnetic resonance device, the uniformity of a magnetic field in the Z direction in the space of a central uniform area of a magnet, namely a constant magnetic field area, is very good, and the peak unevenness (the ratio of the difference value of the highest and the lowest magnetic fields in the area to the central field value), namely pk-pk (the peak uniformity of the magnetic field in the Z axis direction), does not exceed the level of 10ppm (parts per million) in the spherical uniform area. The space size of the central uniform region of the magnet is the key of the design of the superconducting magnet, and the larger central uniform region means that the larger scanning visual field is larger, the tissue range capable of being scanned by a single time is larger, and the imaging speed is higher.

However, at present, a magnetic resonance apparatus generally has a scanning field of view in a constant magnetic field region, and the scanning range of one scanning field of view is limited, so that only one imaging region or a smaller imaging region can be imaged. When the number of the imaging parts is at least two, or the volume of the imaging parts is large, a single scanning view cannot meet the scanning requirement, and the examination bed needs to be moved back and forth to drive the scanning object to move, so that the imaging parts of the scanning object are respectively aligned with the scanning views to perform imaging, the scanning speed and efficiency are reduced, and the use is inconvenient.

Disclosure of Invention

In view of the above, it is necessary to provide a magnetic resonance apparatus and a control method thereof capable of increasing a scanning speed, in order to solve a problem that a scanning speed is low due to a single scanning field.

A magnetic resonance apparatus comprising:

a superconducting magnet having main coils therein, the main coils forming a magnet bore and the main coils being capable of producing one or more homogeneous zones within the magnet bore;

at least one set of gradient coils disposed in the magnet bore in an axial direction; and

at least one group of radio frequency coils which are arranged in the magnet hole along the axial direction and are matched with the at least one group of gradient coils, wherein the at least one group of radio frequency coils can form at least two radio frequency fields;

the homogeneity zone cooperates with at least two of the radio frequency fields such that the magnetic resonance apparatus has at least two scanning fields of view.

In one embodiment, the number of homogeneous zones is one, and the extent of the homogeneous field region is greater than or equal to the extent of the at least two scan fields of view.

In one embodiment, two groups of gradient coils and two groups of radio frequency coils are arranged in the magnet hole at intervals respectively;

or two groups of radio frequency coils and one group of gradient coils which are distributed at intervals are arranged in the magnet hole.

In one embodiment, the uniform areas are arranged at intervals along the axial direction of the magnet hole, and the distance between every two adjacent uniform areas is 0.1-5 times the axial length of the uniform areas.

In one embodiment, the uniform regions are symmetrically distributed about a center of the superconducting magnet; alternatively, the uniform regions are asymmetrically distributed about a center of the superconducting magnet.

In one embodiment, the main coils of the superconducting magnet form two homogeneous regions, each homogeneous region corresponds to one scanning field of view, and each homogeneous region is respectively provided with a group of gradient coils and a group of radio frequency coils.

In one embodiment, the two gradient coils corresponding to different shim regions are of an integral structure, or the two gradient coils corresponding to different shim regions are arranged at intervals.

In one embodiment, the main coils include a first main coil located at an end of the magnet hole and a second main coil located at a central region of the magnet hole, and a size of the first main coil in a radial direction of the magnet hole is larger than a size of the second main coil in the radial direction of the magnet hole.

A control method of a magnetic resonance apparatus including a superconducting magnet, a gradient coil, and a radio frequency coil, the superconducting magnet including a plurality of sets of main coils arranged in an axial direction, the plurality of sets of main coils forming a magnet hole, the gradient coil and the radio frequency coil being arranged in the magnet hole;

the control method comprises the following steps:

exciting the multiple groups of main coils to generate a uniform field area in the magnet hole, wherein the uniform field area covers a first area and a second area;

driving the radio frequency coil while generating a first radio frequency field at the first region and a second radio frequency field at the second region; driving the gradient coils while generating a first gradient field in the first region and a second gradient field in the second region;

or, the radio frequency coil is driven to generate a first radio frequency field in the first area in a first period of time and generate a second radio frequency field in the second area in a second period of time; the gradient coils are driven to generate a first gradient field in the first region during a first period of time and a second gradient field in the second region during a second period of time.

In one embodiment, the magnetic resonance apparatus further includes a scanning bed, and the control method further includes:

driving the scanning bed to the first region in a first time period to perform imaging of a first scanning field of view;

driving the scanning bed to the second region in a second time period to perform imaging of a second scanning field of view;

alternatively, the scanning bed is driven into the first region and the second region, and imaging of the first scanning field of view and imaging of the second scanning field of view are performed.

After the technical scheme is adopted, the invention at least has the following technical effects:

according to the magnetic resonance equipment, the main coil of the superconducting magnet can generate a uniform area of a steady magnetic field in the magnet hole, and the uniform area can be used for at least two scanning visual fields and used for imaging. And, the radio frequency coils disposed in the magnet bore generate at least two (sets of) radio frequency fields in different regions, one for each scan field of view. At least two groups of radio frequency fields can be matched with the uniform area, so that the parts in at least two scanning fields can be scanned and imaged. The superconducting magnet generates the uniform region with at least two scanning visual fields to match with at least two groups of radio frequency fields, the problem that the scanning speed is influenced by the single scanning visual field is effectively solved, at least two scanning visual fields can respectively correspond to a plurality of imaging parts, the simultaneous scanning of the plurality of imaging parts is realized, or the one-time scanning of a large imaging part is realized, the scanning speed and the scanning efficiency are improved, and the use is convenient.

Drawings

Figure 1 is a schematic diagram of a magnetic resonance apparatus in accordance with a first embodiment of the invention;

FIG. 2 is a schematic diagram of two homogeneous zones produced by a superconducting magnet in the magnetic resonance apparatus shown in FIG. 1;

figure 3 is a diagrammatic illustration of a magnetic resonance apparatus in accordance with a second embodiment of the invention;

figure 4 is a diagrammatic view of a magnetic resonance apparatus in accordance with a third embodiment of the invention;

fig. 5 is a schematic diagram of an embodiment of the main coil in the magnetic resonance apparatus shown in fig. 1.

Wherein: 100. a magnetic resonance apparatus; 110. a superconducting magnet; 111. a main coil; 112. a uniform region; 120. a gradient coil; 130. a radio frequency coil; 131. a transmitting coil; 132. a receiving coil; 200. the object is scanned.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, embodiments accompanying figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, but are not intended to indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and are not to be construed as limiting the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless explicitly specified otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. As used herein, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like are for purposes of illustration only and do not denote a single embodiment.

Referring to fig. 1 to 4, the present invention provides a magnetic resonance apparatus 100. The magnetic resonance apparatus 100 is used for scanning an imaging region to obtain a magnetic resonance signal of the imaging region, and a medical staff can diagnose a scanned object 200 according to reconstructed image information of the magnetic resonance signal. Alternatively, the imaging region here mainly refers to a region to be imaged of the scanning object 200 or a region of interest of a doctor. The imaging site may be a tissue site of the head, brain, limbs, abdomen, spine, neck, chest, etc., of the scanning subject 200, or a human organ such as heart, kidney, lower limbs, bladder, etc.

It can be understood that, at present, a magnetic resonance apparatus usually has a scanning field of view in a steady magnetic field region, and the scanning range of one scanning field of view is limited, so that only one imaging region or a smaller imaging region can be imaged. When the number of the imaging parts is at least two, or the volume of the imaging parts is large, a single scanning view cannot meet the scanning requirement, and the examination bed needs to be moved back and forth to drive the scanning object to move, so that the imaging parts of the scanning object are respectively aligned with the scanning views to perform imaging, the scanning speed and efficiency are reduced, and the use is inconvenient.

To this end, the invention provides a novel magnetic resonance apparatus 100. The magnetic resonance device 100 can realize simultaneous scanning imaging of at least two imaging parts, or simultaneous scanning of two different regions at a time period to a larger imaging part, does not need multiple scanning, improves scanning speed and efficiency, and is convenient to use. The specific structure of the magnetic resonance apparatus 100 is described in detail below.

Referring to fig. 1-4, in an embodiment, a magnetic resonance apparatus 100 includes a superconducting magnet 110, at least one set of gradient coils 120, and at least one set of radio frequency coils 130. The superconducting magnet 110 has a main coil 111 and a shielding coil located outside the main coil 111, the main coil 111 can form one or more magnet holes, and the main coil 111 is excited to generate a uniform field region 112 in the magnet holes. At least one set of gradient coils 120 is disposed in the magnet bore along the axial direction, at least one set of radio frequency coils 130 is disposed in the magnet bore along the axial direction and is matched with the at least one set of gradient coils 120, and the at least one set of radio frequency coils 130 forms at least two radio frequency fields. The homogeneity zone 112 is matched to the at least two radio frequency fields such that the magnetic resonance apparatus 110 forms at least two scanning fields of view.

The superconducting magnet 110 is provided in a hollow cylindrical shape, and the hollow portion of the superconducting magnet 110 is a magnet hole extending in the axial direction. The superconducting magnet 110 has a main coil 111 inside thereof, the main coil 111 being capable of generating a uniform region 112 of a steady magnetic field in a magnet bore, and a shield coil for suppressing interference of external electromagnetic waves with the uniform region 112. When the magnetic resonance apparatus 100 is in use, the scanning bed can drive the scanning object 200 to move in the magnet hole, so that the imaging part of the scanning object 200 is located in the uniform region 112 of the magnet hole, so as to scan and image the imaging part.

Also, the superconducting magnet 110 forms the uniform region 112 through the main coil 111 after the magnet holes are formed, and the uniform region 112 can provide a scanning space for at least two scanning fields. It is worth mentioning that one scanning field of view can image one imaging part, and at least two scanning fields of view can scan and image at least two parts to be imaged. In this way, the magnetic resonance apparatus 100 can simultaneously image at least two imaging portions of the scan object 200 through the uniform region 112 of the superconducting magnet 110, thereby improving the scan efficiency and speed.

The gradient coil 120 is disposed at a side of the superconducting magnet 110 facing the magnet hole, i.e., the gradient coil 120 is located in the magnet hole of the superconducting magnet 110 and at an inner wall of the magnet hole of the superconducting magnet 110, and the gradient coil 120 is used for generating a gradient field in the magnet hole. The radio frequency coil 130 is disposed on a side of the superconducting magnet 110 facing the magnet bore, i.e., the radio frequency coil 130 is located in the magnet bore of the superconducting magnet 110, and the radio frequency coil 130 is located on an inner wall of the gradient coil 120 on a side away from the magnet bore, the radio frequency coil 130 being for generating a radio frequency field in the magnet bore. Furthermore, the superconducting magnet 110, the gradient coil 120 and the radio frequency coil 130 are coaxially fixedly assembled.

At least one set of gradient coils 120 is arranged in the axial direction of the magnet bore. The gradient coils 120 can thus correspond to the homogeneity region 112 produced by the main coil 111 in the magnet bore, so that the gradient field can cover the entire homogeneity region 112. It will be appreciated that the number of gradient coils 120 is in principle not limited, as long as it is ensured that the generated gradient field covers the homogeneity zone. At least one set of radio frequency coils 130 is disposed along the axial direction of the magnet bore and generates at least two radio frequency fields in the axial direction along the magnet bore. In this way, the radio frequency coil can correspond to the homogeneous region 112 created in the magnet bore by the main coil 111 such that the radio frequency field can cover the entire homogeneous region 112. It will be appreciated that the number of rf coils 130 is in principle not limited, as long as it is ensured that the generated rf field covers a uniform area.

Also, the radio frequency coils 130 are distributed to correspond to the gradient coils 120. That is, at least two radio frequency fields of the radio frequency coil 130 are in corresponding relation to the gradient coil 120. In this way, the radio frequency field generated by the radio frequency coil 130 and the gradient field generated by the gradient coil 120 can act together in the homogeneous region 112 generated by the main coil 111 to realize the imaging of the imaging part of the scanned object 200. In the uniform region 112, each rf field corresponds to a scanning field, and the number of the scanning fields is increased by the rf coil 130, so as to increase the scanning field, so as to simultaneously scan and image at least two imaging portions, thereby achieving parallel scanning and improving the scanning speed and efficiency.

The magnetic resonance apparatus 100 of the above embodiment generates the uniform region 112 with at least two scanning fields by the superconducting magnet 110, and cooperates with at least two radio frequency fields, so as to effectively solve the problem that the scanning speed is affected by the single scanning field, so that at least two scanning fields can respectively correspond to a plurality of imaging portions, thereby realizing simultaneous scanning of a plurality of imaging portions, or realizing one-time scanning of a larger imaging portion, improving the scanning speed and efficiency, and facilitating use.

In an embodiment, the number of gradient coils 120 is at least two, the at least two gradient coils 120 being arranged in the axial direction of the magnet bore. In this way, at least two gradient coils 120 can correspond to the homogeneous region 112 generated by the main coil 111 in the magnet bore, so that the gradient field can cover the entire homogeneous region 112. The number of the radio frequency coils 130 is also two, and at least two radio frequency coils 130 are arranged in the axial direction of the magnet bore. In this way, the at least two radio frequency coils 130 can correspond to the homogeneous region 112 generated by the main coil 111 in the magnet bore, such that the radio frequency field can cover the entire homogeneous region 112.

Also, at least two radio frequency coils 130 are distributed corresponding to the at least two gradient coils 120. That is, the radio frequency coil 130 is in a corresponding relationship with the gradient coil 120. In this way, the radio frequency field generated by the radio frequency coil 130 and the gradient field generated by the gradient coil 120 can be superimposed in the homogeneous region 112 generated by the main coil 111, so as to realize imaging of the imaging part of the scanned object 200. In the uniform region 112, each rf coil 130 corresponds to one scanning field, and the number of scanning fields is increased by the rf coils 130, so as to increase the scanning fields, so as to simultaneously perform scanning imaging on at least two imaging portions, thereby implementing parallel scanning and improving the scanning speed and efficiency.

In one embodiment, two sets of gradient coils 120 and two sets of radio frequency coils 130 are disposed in the magnet bore at spaced intervals, respectively. That is, the two sets of RF coils 130 generate two RF fields corresponding to the two gradient fields generated by the two sets of gradient coils 120, respectively, to form two scanning fields in the homogeneous region 112.

In one embodiment, two sets of RF coils 130 and one set of gradient coils 120 are spaced apart in the magnet bore. That is, two sets of RF coils 130 generate two RF fields, and the gradient fields generated by the gradient coils 120 can completely cover the two RF fields, so that the two RF fields form two scanning fields in a uniform region.

In one embodiment, the gradient fields of the gradient coils 120 and the radio frequency fields of the radio frequency coil 130 cooperate with the main magnetic field of the homogeneous region 112 in each scan field of view for imaging.

Referring to fig. 1-4, in an embodiment, a superconducting magnet 110 includes a cryostat and main coils 111 disposed in the cryostat. The cryostat is a multi-layer container structure comprising an outer container, an inner container and a shield. The outer container is provided with a through hole which extends along the containing cavity in the surrounding mode, the through hole is a magnet hole, the inner container is arranged in the containing cavity, and the shielding layer is arranged between the inner container and the outer container.

The inner container is surrounded by a shielding layer, which is a hollow and closed cylindrical structure. The inner vessel contains liquid helium and a superconducting magnetic coil is also disposed in the inner vessel. The main coil 111 is immersed in liquid helium to cool the main coil 111, reduce the temperature of the main coil 111, and ensure that the superconducting magnet 110 can reliably work. Of course, in another embodiment of the present invention, a cooling pipe may be provided on the outer periphery of the superconducting magnet 110, and a coolant may be introduced into the cooling pipe to cool the superconducting magnet 110. The shielding layer can shield heat radiated to the inner container, and heat leakage of the inner container is reduced, so that the aims of reducing evaporation and loss of the liquid helium are fulfilled.

The interlayer space between the outer wall of the inner container and the inner wall of the outer container is set to be a vacuum environment, so that the heat convection from the outside to the inner container is reduced, and meanwhile, the shielding layer is arranged in the mounting space to reduce the heat radiation to the inner container, so that the heat conduction from the outside environment to the inner container is reduced.

The outer container is a hollow and closed cylindrical structure, and the shielding layer is arranged in the outer container. The outer container is provided coaxially with the inner container and the shield layer. The inner container and the shielding layer are protected by the outer container, so that heat conduction from the external environment to the inner container is reduced, the evaporation capacity of liquid helium in the inner container is reduced, and the liquid helium can reliably cool the main coil 111.

Referring to fig. 1 and 4, in an embodiment, the number and/or size of homogeneous zones 112 of superconducting magnet 110 is adjusted by optimizing the number and/or location of main coils 111 in superconducting magnet 110. That is, the number and size of homogeneous regions 112 of superconducting magnet 110 may be achieved by optimizing main coils 111 such that homogeneous regions 112 can accommodate at least two scan fields of view.

The superconducting magnet 110 may include a plurality of groups of main coils, and each group of the main coils has main coil units of different sizes in the magnet aperture direction. In one embodiment, the main coils of the superconducting magnet 110 include a plurality of main coil units that surround to form a magnet bore, and the plurality of main coil units form two sets of coaxially disposed main coils with respect to a center of the magnet bore. Each group of the main coils may include two or more main coil units having different sizes in the radial direction of the magnet aperture, and a plurality of the main coil units belonging to the same group of the main coils are arranged in a staircase shape. In order to prevent the main magnetic field generated by the main coil units from receiving the interference of external electromagnetic waves, shielding coil units may be inserted at adjacent positions of the plurality of main coil units.

For convenience of explaining the influence of the positions of the coils in the main coil 111 on the number and size of the uniform regions 112, an example is added here for description, but the number and size of the uniform regions 112 are not limited to the positions of the coils in this example, and other coil positions may be used.

Fig. 5 is a schematic diagram of a set of main coils according to an embodiment of the present application, with the horizontal axis representing coordinates along the axial direction of the magnet bore and the vertical axis representing coordinates along the radial direction of the magnet bore. The group of main coils form a magnet hole with the central aperture of 0.9m, and another group of main coils are symmetrically distributed on the group of main coils and matched with the group of main coils to form a superconducting magnet 110 with the axial length of 2 meters. The group of main coils comprises six main coil units such as C2, C4-C8 and the like, and C1 and C3 are shielding coil units. Six main coil units such as C2 and C4-C8 are arranged at different positions along the radial direction of the magnet hole and are arranged in a ladder shape, C3 is arranged in the middle of each main coil unit, and C1 is arranged on the outer side of each main coil unit.

During excitation, the current directions of six main coil units such as C2, C4-C8 and the like are the same, and the current directions of two shielding coil units such as C1 and C3 are the same and are opposite to the current directions of C2 and C4-C8. Six main coil units C2, C4-C8, etc. have different coordinates in the magnet hole radial direction, and the main coil unit C2 (first main coil unit) located at the end of the magnet hole has a larger size in the magnet hole radial direction with respect to the main coil units C7, C8 (second main coil unit) located at the center region of the magnet hole. In this embodiment, eight coil units, C1-C8, are coaxially arranged along the magnet bore axis, respectively.

In the present example, two symmetrical uniform zones are created on opposite sides of a center distance of 0.35m, where pk-pk uniformity is 19ppm within a 0.4m sphere area; within a 0.3m sphere area, pk-pk homogeneity is 6ppm, which homogeneity region can be used to form an imaging field of view.

In this embodiment, the spacing L between C5 and C6 in the axial direction of the magnet bore ₅₆ Less than the spacing L between C2 and C4 in the axial direction of the magnet bore ₂₄ I.e. adjacent main coil units located in the homogeneous region have a smaller pitch with respect to adjacent main coil units located in the heterogeneous region.

The coordinate relationship of the positions of the coil units of the superconducting magnet in fig. 5 is detailed in the following table, in which a is the ordinate, z is the abscissa, the difference between the two abscissas is the width of the coil, and the difference between the two ordinates is the height of the coil.

C		a1	a2	z1	z2
						C 1		0.850196	0.864544	0.5834794	0.822623
C 2		0.482491	0.59606	0.9451404	0.990568
						C 3		0.49714	0.52162	0.8407204	0.92208
C 4		0.517215	0.53905	0.6752086	0.76255
						C 5		0.519606	0.54135	0.499499	0.553858
C 6		0.511569	0.523671	0.3233218	0.403998
						C 7		0.50401	0.51375	0.1400974	0.237504
C 8		0.495555	0.508005	0.00847	0.045246

Compared to the conventional superconducting magnet, the superconducting magnet 110 of the present invention has an increased number of main coils 111, an increased magnet size, and accordingly, an increased magnet cost.

In other embodiments of the present invention, a larger homogeneous region 112 is also formed in the magnet bore by optimizing the number and location of the primary coils 111, which also enables the homogeneous region 112 to accommodate at least two scanning fields of view.

Referring to fig. 4, in one embodiment, the number of homogeneous regions 112 is one, and the extent of homogeneous region 112 is equal to or greater than the extent of at least two scan fields of view. That is, the main coil 111 creates a single homogeneous region 112 near the geometric center of the superconducting magnet 110, but the homogeneous region 112 has certain axial and radial dimensions, i.e., the main coil 111 creates a larger homogeneous region 112 in the magnet bore. A larger uniform region 112 can accommodate at least two scanning fields of view simultaneously, thereby enabling parallel scanning of the imaged region, increasing scanning speed and small wheel. It is understood that one larger uniform region 112 in this embodiment can cover at least two smaller uniform regions 112 in the embodiments described below.

Referring to fig. 1 to 3, in an embodiment, the number of the uniform regions 112 is at least two, at least two uniform regions 112 are arranged at intervals along the axial direction of the magnet hole, and each uniform region 112 corresponds to the rf field of one rf coil 130. That is, at least two axially disposed homogeneous zones 112 can be formed in the magnet bore by optimizing the number and location of the main coils 111 in the superconducting magnet 110. Each uniformity region 112 accommodates at least one scan field of view. Furthermore, each homogeneity region 112 corresponds to the radio frequency field of one radio frequency coil 130 and the gradient field of the gradient coil 120. In this way, the magnetic resonance apparatus 100 can scan and image at least two imaging regions of the scan subject 200 in the homogeneous region 112 of the magnet bore by the cooperation of the gradient coil 120 and the radio frequency coil 130.

It will be appreciated that after the main coil 111 produces at least two homogeneous regions 112 in the magnet bore, the size of a single homogeneous region 112 is reduced compared to the current homogeneous region, however, the overall size of the at least two homogeneous regions 112 is much larger than the current homogeneous region to accommodate at least two scanning fields of view, enabling simultaneous scanning imaging of at least two imaging sites.

Alternatively, the uniform regions 112 may be spaced apart from one another. That is, there is a distance between adjacent homogeneous regions 112. Of course, in other embodiments of the present invention, two adjacent homogeneous regions 112 may be disposed in a fitting manner. Further, the uniform region 112 is circular or elliptical in shape.

In one embodiment, the distance between two adjacent uniform areas 112 is 0.1-5 times the axial length of the uniform areas 112. It is understood that the distance between two adjacent uniform regions 112 cannot be too large, and if the distance between two adjacent uniform regions 112 is too large, the axial dimension of the superconducting magnet 110 may be increased. Therefore, when the distance between two adjacent uniform regions 112 is 0.1 to 5 times the axial length of the uniform region 112, the imaging performance in the uniform region 112 can be ensured, and the axial dimension of the superconducting magnet 110 can be reduced.

Further, the uniform region 112 is disposed in an elliptical shape. Therefore, the radial size of the magnet hole can be reduced, and further the radial size of the superconducting magnet 110 is reduced, so that the overall volume of the magnetic resonance equipment 100 is small, the miniaturization design of the magnetic resonance equipment 100 is facilitated, and meanwhile, the cost can be reduced.

In an embodiment, the uniform regions 112 are symmetrically distributed about the center of the superconducting magnet 110; alternatively, the uniform regions 112 are asymmetrically distributed about the center of the superconducting magnet 110. When the number of the uniform regions 112 is one, the center of the uniform region 112 is located on the vertical axis of the superconducting magnet 110, that is, the uniform region 112 is symmetrical with respect to the vertical axis of the superconducting magnet 110, and the uniform regions 112 are symmetrically distributed with respect to the center of the superconducting magnet 110. The vertical axis here is the central axis of the superconducting magnet 110 in the vertical direction. Of course, the center of the uniform region 112 may also be offset from the vertical axis of the superconducting magnet 110, that is, the uniform region 112 is asymmetric about the vertical axis of the superconducting magnet 110, i.e., the uniform region 112 is asymmetrically distributed about the center of the superconducting magnet 110.

When the number of the uniform regions 112 is at least two, the number of the uniform regions 112 is exemplified as two. Two uniform regions 112 are located on either side of the vertical axis of the superconducting magnet 110. The two uniformity zones 112 may be symmetrical about the vertical axis or asymmetrical about the vertical axis. When the number of the uniform regions 112 is three, one of the uniform regions 112 is located at the middle position, and the other two uniform regions 112 are located at both sides of the middle uniform region 112. The three uniform regions 112 may or may not be symmetrical about the vertical axis. When the number of the uniform regions 112 is larger, the layout manner of the uniform regions 112 is substantially the same, and the description thereof is omitted here.

Optionally, the magnetic resonance apparatus 100 further comprises a controller electrically connected to the gradient coil 120 and the radio frequency coil 130, respectively. The controller can respectively control the at least two gradient coils 120 and the at least two radio frequency coils 130, etc., to respectively perform scan imaging on at least two imaging portions of the scan object 200 located in the homogeneous region 112, that is, the magnetic resonance apparatus 100 obtains at least two independent scan fields. Thus, the magnetic resonance apparatus 100 can scan at least two imaging sites simultaneously in a unit time at a scanning speed at least twice that of the conventional system.

Referring to fig. 1 and 3, in one embodiment, each rf coil 130 includes a transmitting coil 131 and a receiving coil 132, the receiving coil 132 is disposed inside the gradient coil 120, and the transmitting coil 131 is located between the gradient coil 120 and the receiving coil 132. Each transmitting coil 131 forms a radio frequency field. The transmitting coil 131 is located inside the gradient coil 120, and the receiving coil 132 is located inside the transmitting coil 131. The transmit coil 131 is used for transmitting magnetic resonance signals, and the receive coil 132 is used for receiving magnetic resonance signals passing through the scan object 200 to realize scan imaging of an imaging region.

When the number of the radio frequency coils 130 is at least two, the number of the transmitting coils 131 is at least two, the number of the receiving coils 132 is also at least two, and at least two transmitting coils 131 are disposed along the axial direction of the magnet hole, and at least two receiving coils 132 are disposed along the axial direction of the magnet hole. The receiving coil 132, the transmitting coil 131, the gradient coil 120, and the superconducting magnet 110 are sleeved in layers in the radial direction, the receiving coil 132 is located at the innermost layer, and the superconducting magnet 110 is located at the outermost layer.

Referring to fig. 1 and 3, in an embodiment, two transmitting coils 131 of two adjacent rf coils 130 are of a unitary structure, or two transmitting coils 131 are spaced apart. Optionally, two adjacent transmitting coils 131 are of a unitary structure, that is, two adjacent transmitting coils 131 form a whole, and the axial length of two adjacent transmitting coils 131 corresponds to at least two gradient coils 120 and at least two receiving coils 132. Of course, in other embodiments of the present invention, at least two transmitting coils 131 may be disposed at intervals. That is, two adjacent transmitting coils 131 are independent components, and have a certain distance therebetween in the axial direction.

It should be noted that both the two types of arrangement modes of the transmitting coil 131 can correspond to the uniform region 112 generated by the main coil 111 and match at least two scanning fields of view, so as to realize simultaneous scanning imaging of at least two imaging portions and improve scanning speed and efficiency.

Referring to fig. 1 and 3, in an embodiment, two receiving coils 132 of two adjacent rf coils 130 are of a unitary structure, or the two receiving coils 132 are spaced apart. Optionally, the two adjacent receiving coils 132 are of a unitary structure, that is, the two adjacent receiving coils 132 form a whole, and the axial length of the two adjacent receiving coils 132 corresponds to the at least two gradient coils 120 and the at least two transmitting coils 131. Of course, in other embodiments of the present invention, at least two receiving coils 132 may be disposed at intervals. That is, the adjacent two receiving coils 132 are independent components, and have a certain distance therebetween in the axial direction.

It should be noted that both the two types of arrangement modes of the transmitting coil 131 can correspond to the uniform region 112 generated by the main coil 111 and match at least two scanning fields of view, so as to realize simultaneous scanning imaging of at least two imaging portions and improve scanning speed and efficiency.

Referring to fig. 1 and 3, in one embodiment, in each rf coil 130, the receiving coil 132 and the transmitting coil 131 are of a single structure, or the receiving coil 132 and the transmitting coil 131 are separately disposed. Optionally, the receiving coil 132 and the transmitting coil 131 of the same radio frequency coil 130 are of a unitary construction. That is, the transmitting coil 131 and the receiving coil 132 of the same radio frequency coil 130 are integrated. Of course, in other embodiments of the present invention, the receiving coil 132 and the transmitting coil 131 of the same RF coil 130 can be separated from each other, and they are two independent components.

It can be understood that the transmitting coil 131 and the receiving coil 132 of the at least two rf coils 130, whether disposed integrally or separately, can correspond to the homogeneous region 112 generated by the main coil 111 and match the at least two scanning fields of view, thereby achieving simultaneous scanning imaging of at least two imaging regions and improving scanning speed and efficiency.

Referring to fig. 1 and 3, in an embodiment, two adjacent gradient coils 120 are of a unitary structure, or two adjacent gradient coils 120 are spaced apart. Optionally, at least two gradient coils 120 may also be provided at intervals. That is, two adjacent gradient coils 120 are independent components, and are spaced apart from each other in the axial direction. In this way, different scanning parameters and sequences can be respectively selected for at least two imaging parts according to different tissue characteristics of the imaging parts, thereby providing more possibilities for the application of magnetic resonance.

Of course, in other embodiments of the present invention, two adjacent gradient coils 120 are of a unitary structure, that is, two adjacent gradient coils 120 form a whole, and the axial length of two adjacent gradient coils 120 corresponds to at least two receiving coils 132 and at least two transmitting coils 131. When the linear uniform portion of the gradient coil 120 is large enough, a single gradient coil 120 can be used in cooperation with the uniform region 112, but the tissue of the imaging portion cannot be selected individually, and the scanning speed and efficiency can be improved as well as the simultaneous scanning imaging of at least two portions without moving the scanning bed.

It should be noted that both the two types of arrangement modes of the transmitting coil 131 can correspond to the uniform region 112 generated by the main coil 111 and match at least two scanning fields of view, so as to realize simultaneous scanning imaging of at least two imaging portions and improve scanning speed and efficiency.

Referring to fig. 1-4, in a particular embodiment, a homogeneous region 112 of a main coil 111 of a superconducting magnet 110 corresponds to two scanning fields of view. The number of radio frequency coils 130 is two, the number of gradient coils 120 is also two, one gradient coil 120 for each radio frequency coil 130, and one scan field of view for each radio frequency coil 130. That is, the magnetic resonance apparatus 100 can simultaneously scan and image two imaging portions of the scanned object 200, and the scanning speed is improved by at least two times compared with the current single scanning field of view.

In this particular embodiment, the number of radio frequency coils 130 and gradient coils 120 is two to match two scan fields of view. Of course, in other embodiments of the present invention, the number of the radio frequency coils 130 and the gradient coils 120 may also be three or more. The present invention is described by taking only two numbers of the rf coils 130 and the gradient coils 120 as an example, and the principle when the number of the rf coils 130 and the gradient coils 120 is more is substantially the same as the principle when the number of the rf coils 130 and the gradient coils 120 is two, but the overall size and the cost are increased, which is not repeated herein.

In this embodiment, the number of the uniform regions 112 formed by the main coil 111 may be one or two. Furthermore, the layout of the gradient coil 120, the transmitting coil 131 and the receiving coil 132 in the rf coil 130 can be adjusted accordingly. The following describes various aspects in detail.

In the first embodiment of the present invention, as shown in fig. 1, the main coils 111 of the superconducting magnet 110 form two homogeneous regions 112, each homogeneous region 112 corresponds to one scanning field of view, the number of the rf coils 130 is two, the number of the gradient coils 120 is two, and each rf coil 130 is disposed corresponding to one homogeneous region 112. Also, in this embodiment, the transmitting coils 131 of two adjacent rf coils 130 are spaced apart and respectively correspond to two uniform regions 112, the receiving coils 132 are spaced apart and respectively correspond to two uniform regions 112, and the gradient coils 120 are spaced apart and respectively correspond to two uniform regions 112.

To better illustrate the size of the homogeneity region 112, a magnet bore of 90cm aperture is used to illustrate the differences in homogeneity region of the magnetic resonance apparatus 100 of the present invention compared to current magnetic resonance apparatus. In the current magnetic resonance equipment, on a 1.5T superconducting magnet with an aperture of 90cm, the uniform area is generally a sphere of 50 cm; after the scheme is adopted, the main coil 111 is optimized on the premise of keeping the aperture of 90cm, two uniform areas 112 with the diameter of 40cm can be obtained, generally, the central axial gap of the two uniform areas 112 is not less than 40cm, and the sum of the axial lengths of the two uniform areas 112 is 80 cm. It is apparent that the spatial size of the individual homogeneous regions 112 is reduced, but the number and overall size of the homogeneous regions 112 is much larger than that of current superconducting magnets.

The controller of the magnetic resonance apparatus 100 can respectively control the two gradient coils 120 and the two radio frequency coils 130, etc., so as to respectively perform scan imaging on the imaging portions of the scan object 200 located in the two homogeneous regions 112, that is, the magnetic resonance apparatus 100 obtains two independent scan fields. Thus, the magnetic resonance apparatus 100 can scan two imaging sites simultaneously in a unit time at a scanning speed at least twice that of the conventional system. In addition, different scanning parameters and sequences can be respectively selected for the two imaging parts according to different tissue characteristics of the imaging parts, so that more possibilities are provided for the application of magnetic resonance.

In a third embodiment of the present invention, as shown in fig. 4, the main coil 111 of the superconducting magnet 110 forms a uniform region 112, the size of the uniform region 112 is large, the uniform region can correspond to the two gradient coils 120 and the two rf coils 130, respectively, and the uniform region 112 can match two scanning fields of view. Also, in this embodiment, the transmitting coils 131 of two adjacent rf coils 130 are spaced apart and respectively correspond to two uniform regions 112, the receiving coils 132 are spaced apart and respectively correspond to two uniform regions 112, and the gradient coils 120 are spaced apart and respectively correspond to two uniform regions 112.

The magnetic resonance apparatus 100 of the present invention generates the uniform region 112 capable of matching at least two scanning fields of view through the main coil 111 in the superconducting magnet 110, and performs simultaneous scanning imaging on at least two portions of the scanned object 200 to obtain image information of at least two imaged portions, thereby achieving the purposes of improving scanning speed and efficiency and facilitating use.

The invention also provides a method of controlling a magnetic resonance apparatus 100. The magnetic resonance apparatus 100 comprises a superconducting magnet 110, a gradient coil 120 and a radio frequency coil 130, the superconducting magnet 110 comprises a plurality of sets of coaxially arranged main coils 111, the plurality of sets of main coils 111 form a magnet bore, and each set of main coils 111 comprises two main coils 111 having different sizes in a radial direction of the magnet bore in which the gradient coil 120 and the radio frequency coil 130 are arranged;

the control method comprises the following steps:

exciting the multiple groups of the main coils 111 to generate a uniform field area in the magnet hole, wherein the uniform field area covers a first area and a second area;

driving the rf coil 130 while generating a first rf field in the first region and a second rf field in the second region; driving the gradient coil 120 while generating a first gradient field in the first region and a second gradient field in the second region;

or, the rf coil 130 is driven to generate a first rf field in the first region during a first period and a second rf field in the second region during a second period; the gradient coil 120 is driven to generate a first gradient field in the first region during a first period and a second gradient field in the second region during a second period.

When the magnetic resonance apparatus 100 simultaneously images a plurality of imaging portions, the magnetic resonance apparatus 100 excites the plurality of sets of main coils 111 and generates a shim field region in the magnet bore so that the shim field region covers the first region and the second region. Then, the radio frequency coil 130 is driven, and a first radio frequency field is generated in the first area and a second radio frequency field is generated in the second area simultaneously; the gradient coils 120 are re-driven while generating a first gradient field in the first region and a second gradient field in the second region. In this case, two scanning fields of view are formed in the first region and the second region of the magnet hole, and two imaging portions can be imaged at the same time.

Of course, after the magnetic resonance apparatus 100 excites the main coil 111, the rf coil 130 may be driven to generate a first rf field in the first region for a first period of time and a second rf field in the second region for a second period of time; the gradient coil 120 is driven to generate a first gradient field in the first region during a first period and a second gradient field in the second region during a second period. In this case, two scanning fields of view are formed in the first region and the second region of the magnet hole, and two imaging portions can be imaged at the same time.

In an embodiment, the magnetic resonance apparatus 100 further comprises a scanning bed, and the control method further comprises:

driving the scanning bed to the first region in a first time period to perform imaging of a first scanning field of view;

and driving the scanning bed to the second area in a second time interval so as to execute imaging of a second scanning visual field.

In one embodiment, the control method may include: the scanning bed is driven into a first region and a second region, a portion of the scanning bed being in the first region and another portion of the scanning bed being in the second region, and imaging of the first scanning field of view and imaging of the second scanning field of view are performed simultaneously.

When imaging the scan object 200, the scan object 200 is located on the scan bed, and the scan bed is controlled to move in and out of the first region or the second region. When the scanning bed drives the scanning object 200 to enter the first region or the second region, the scanning operation can be executed through the scanning visual field of the corresponding region, and the scanning imaging of the imaging part is realized.

In one embodiment, the magnetic resonance apparatus 100 includes a multi-nuclei driver including a multi-nuclei pulse sequencer, a transmission coil, a radio frequency amplification system, and the like, for driving the radio frequency coil to generate radio frequency pulse signals having a plurality of different frequencies, thereby obtaining magnetic resonance signals of the tissue under test under a plurality of nuclei. The multi-core pulse sequence generator is used for generating required radio frequency pulses, changing radio frequency phases, triggering sampling and accurately controlling the working time sequence among all parts in the multi-core radio frequency generation system; the transmitting coil is used for generating a plurality of radio frequency pulse signals with different Larmor frequency bands, the radio frequency pulse signals are amplified through the radio frequency amplifier to obtain high-energy radio frequency pulse signals, and the high-energy radio frequency pulse signals act on tissues and organs of a detection object to obtain nuclear magnetic resonance signals. In this embodiment, a first region may be provided with a transmitting coil 131 for generating a first radio frequency pulse, a second region may be provided with a transmitting coil 131 for generating a second radio frequency pulse, and the transmitting coils 131 of both regions are simultaneously connected to the multi-nuclei pulse sequencer. Correspondingly, the control method comprises the following steps: generating a first pulse having a frequency corresponding to a first type of nucleus in the first region; generating a second pulse having a frequency corresponding to a second type of nucleus in the second region; simultaneously receiving a first magnetic resonance signal excited by a first type of nucleus and a second magnetic resonance signal excited by a second type of nucleus; and generating multi-type magnetic resonance images corresponding to the multi-type atomic nuclei according to the first magnetic resonance signals and the second magnetic resonance signals. In the embodiment of the application, multi-nuclear magnetic resonance imaging can be realized simultaneously.

All possible combinations of the technical features of the above embodiments may not be described for the sake of brevity, but should be considered as within the scope of the present disclosure as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent should be subject to the appended claims.

Claims (10)

1. A magnetic resonance apparatus, characterized by comprising:

a superconducting magnet having a main coil therein, the main coil forming a magnet bore and capable of creating one or more homogeneous regions within the magnet bore;

at least one set of gradient coils disposed in the magnet bore in an axial direction; and

at least one group of radio frequency coils which are arranged in the magnet hole along the axial direction and are matched with at least one group of gradient coils, wherein at least one group of radio frequency coils can form at least two radio frequency fields;

the homogeneity region is coordinated with at least two of the radio frequency fields, so that the magnetic resonance apparatus has at least two scanning fields of view.

2. The magnetic resonance apparatus of claim 1, wherein the number of homogeneous zones is one and the extent of the homogeneous field region is greater than or equal to the extent of the at least two scan fields of view.

3. The magnetic resonance apparatus of claim 1, wherein two sets of the gradient coils and two sets of the radio frequency coils are disposed in the magnet bore at intervals;

or two groups of radio frequency coils and one group of gradient coils which are distributed at intervals are arranged in the magnet hole.

4. The magnetic resonance apparatus according to claim 1, wherein a plurality of the homogeneous zones are arranged at intervals in an axial direction of the magnet hole, and a distance between two adjacent homogeneous zones is 0.1 to 5 times an axial length of the homogeneous zone.

5. The MR apparatus according to claim 4, wherein the homogeneous regions are symmetrically distributed about a center of the superconducting magnet; alternatively, the uniform regions are asymmetrically distributed about a center of the superconducting magnet.

6. The mrd of claim 1, wherein the main coils of the superconducting magnet form two homogeneous regions, one for each field of view, and each homogeneous region is provided with a set of gradient coils and a set of rf coils.

7. The apparatus of claim 6, wherein the two gradient coils corresponding to different shim regions are of unitary construction or are spaced apart.

8. The magnetic resonance apparatus of claim 6, wherein the main coils include a first main coil located at an end of the magnet bore and a second main coil located at a central region of the magnet bore, and wherein a dimension of the first main coil in a radial direction of the magnet bore is larger than a dimension of the second main coil in the radial direction of the magnet bore.

9. A control method of a magnetic resonance apparatus, characterized in that the magnetic resonance apparatus includes a superconducting magnet, gradient coils, and radio frequency coils, the superconducting magnet includes a plurality of sets of main coils arranged in an axial direction, the plurality of sets of main coils form a magnet hole, and the gradient coils and the radio frequency coils are arranged in the magnet hole;

the control method comprises the following steps:

exciting the multiple groups of main coils to generate a uniform field area in the magnet hole, wherein the uniform field area covers a first area and a second area;

driving the radio frequency coil while generating a first radio frequency field at the first region and a second radio frequency field at the second region; driving the gradient coils while generating a first gradient field in the first region and a second gradient field in the second region;

or, the radio frequency coil is driven to generate a first radio frequency field in the first area in a first period of time and generate a second radio frequency field in the second area in a second period of time; the gradient coil is driven to generate a first gradient field in the first region during a first period and a second gradient field in the second region during a second period.

10. The method of controlling a magnetic resonance apparatus according to claim 9, further comprising a scanning bed, the method further comprising:

driving the scanning bed to the first region in a first time period to perform imaging of a first scanning field of view;

driving the scanning bed to the second region in a second time period to perform imaging of a second scanning field of view;

alternatively, the scanning bed is driven into the first and second regions and imaging of the first scanning field of view and imaging of the second scanning field of view are performed.

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