Non-cylindrical gradient coil unit

Abstract

The invention relates to a gradient coil unit comprising a first conductor structure arranged within a first shaped portion, a second conductor structure arranged within a second shaped portion, wherein - the first conductor structure and the second conductor structure together are configured for generating a magnetic field gradient along a first direction, - the first shaped portion and the second shaped portion are arranged non-intersectingly, opposite to each other and separated by a cavity, and - the first shaped portion has a circular arc segment as a cross section.

Description

TECHNICAL FIELD

[0001] The invention relates to a non-cylindrical gradient coil unit configured for fitting into a hollow cylindrical magnet unit of a magnetic resonance device and to a magnetic resonance device comprising such a non-cylindrical gradient coil unit. BACKGROUND

[0002] In a magnetic resonance device, a body of an examination subject, in particular a patient, to be examined is subjected to a relatively high main magnetic field, for example 1.5 or 3 or 7 Tesla, by means of a magnet unit. Additionally, gradient pulses are output by means of a gradient coil unit. Then, by means of a suitable antenna device, high-frequency pulses, for example excitation pulses, are emitted via a radio-frequency antenna unit, which cause the nuclear spins of certain atoms resonantly excited by the high-frequency pulses to tilt by a defined flip angle with respect to the magnetic field lines of the main magnetic field. Upon relaxation of the nuclear spins, high-frequency signals, so-called magnetic resonance signals, are emitted, which are received by means of a suitable radio-frequency antenna and then further processed. Finally, from the raw data thus acquired, the desired image data can be reconstructed. The gradient coil unit is usually designed for generating a magnetic field gradient in at least one spatial direction. The magnet unit and the gradient coil unit are each typically configured in a hollow cylindrical manner, and the gradient coil unit is arranged within the cavity of the magnet unit. Within the gradient coil unit, there is usually a patient receiving region in which the examination subject is supported during recording of the magnetic resonance signals. It is known that a larger patient receiving region is associated with greater comfort for the examination subject and higher costs for manufacturing the magnetic resonance device. SUMMARY

[0003] It was an object underlying the present invention to specify a gradient coil unit and a magnetic resonance device which enable a high comfort for the examination subject to be realized at low costs. This object is achieved by the gradient coil unit and the magnetic resonance device according to the invention. Advantageous design embodiments are described in the following.

[0004] The gradient coil unit according to the invention is configured for fitting into a hollow cylindrical magnet unit having an inner radius and a magnet length along a cylinder axis of the magnetic resonance device. The gradient coil unit according to the invention comprises a first conductor structure arranged within a first shape portion and a second conductor structure arranged within a second shape portion, wherein

[0005] the first conductor structure and the second conductor structure together are configured for generating a magnetic field gradient along a first direction,

[0006] the first shape portion and the second shape portion are arranged non-intersectingly, opposite to each other and separated by a cavity, and

[0007] The first shape portion has a circular arc segment as a cross section perpendicular to the cylinder axis.

[0008] The conductor structure, in particular the first conductor structure and / or the second conductor structure, generally comprises an electrical conductor. The geometrical arrangement of the electrical conductor can be referred to as the conductor structure.

[0009] The first conductor structure together with the second conductor structure is configured for generating a magnetic field gradient along a first direction. The first direction is generally a spatial direction, preferably parallel and / or perpendicular to the cylinder axis of the magnetic resonance device and / or horizontal and / or vertical. The first conductor structure and the second conductor structure are generally actuated by applying a current in the first conductor structure and the second conductor structure. The electrical conductor generally connects the first conductor structure with the second conductor structure. The first conductor structure and the second conductor structure can be connected to each other in series, in particular by using the electrical conductor. The first conductor structure and the second conductor structure can also be connected to each other by a parallel circuit. Actuating the conductor structure, in particular the first conductor structure and the second conductor structure, comprised by the gradient coil unit for generating a magnetic field gradient is generally achieved by applying a current in the conductor structure. The conductor structure generally comprises copper and / or aluminum and / or another low-resistance material.

[0010] The first conductor structure is generally surrounded and / or encircled by the first shape portion. The first conductor structure can be embedded and / or injected into the first shape portion. The first conductor structure is generally spatially fixed by the first shape portion. The first shape portion can comprise a resin and / or a plastic and / or at least one fiber reinforcement. The second conductor structure is generally surrounded and / or encircled by the second shape portion. The second conductor structure can be embedded and / or injected into the second shape portion. The second conductor structure is generally spatially fixed by the second shape portion. The second shape portion can comprise a resin and / or a plastic and / or at least one fiber reinforcement. The first conductor structure and / or the second conductor structure can be configured in a spiral and / or saddle shape and / or as a segmented coil. The first conductor structure and the second conductor structure are preferably together configured for generating a linear magnetic field gradient along a first direction. The first conductor structure and the second conductor structure can also together be configured for generating a non-linear and / or non-uniform magnetic field gradient, referred to in the specialist literature as Patloc and / or Flatloc. The first conductor structure and the second conductor structure generally together form a primary coil. In order to shield the magnetic field gradient generated by the first conductor structure and the second conductor structure, which is located outside the patient receiving region, in particular outside the cavity, the gradient coil unit preferably comprises a secondary coil, which can comprise a secondary first conductor structure and a secondary second conductor structure. The secondary first conductor structure and the secondary second conductor structure can be arranged radially outside the first conductor structure and the second conductor structure.

[0011] The first and second shaped portions are non-intersecting and preferably have no spatial overlap in this regard. At least the first shaped portion preferably has a circular arc segment as a cross section perpendicular to the cylinder axis in a plane defined by a vertical line and a horizontal line. The profile of the circular arc segment typically comprises a circular arc and a circular chord. The radius defining the circular arc is typically at most 20%, preferably at most 10%, particularly preferably at most 5% smaller than the inner radius of the hollow cylindrical magnet unit. The circular chord typically defines the side of the first shaped portion facing the examination object. The circular arc typically defines the side of the first shaped portion facing the magnet unit. The first and second shaped portions are typically configured for fitting into the interior of the hollow cylindrical magnet unit, in particular into its hollow region. The cavity between the first and second shaped portions typically comprises the examination region and is designed for at least partially accommodating the examination object. The cylinder axis typically extends through the cavity and / or is located outside the first and / or second shaped portion.

[0012] Compared to conventional hollow cylindrical gradient coil units, the non-cylindrical gradient coil unit according to the application requires less space and / or is shaped such that the hollow cylindrical region of the magnet unit is utilized by the first and second shaped portions at locations where the comfort of the examination object is only slightly impaired. In particular, the locations can be adapted to the anatomy of the examination object by the first and second shaped portions. This improves the comfort of the examination object at low cost in case the inner radius of the magnet unit is unchanged. Likewise, the inner radius of the magnet unit can be reduced at the same comfort of the examination object, whereby the magnet unit and thus also the magnetic resonance device can be manufactured at low cost.

[0013] One embodiment of the gradient coil unit proposes that the profile of the cross section of the second shaped portion perpendicular to the cylinder axis has a circular arc with an inner radius. The second shaped portion preferably has a circular arc segment as a cross section perpendicular to the cylinder axis in a plane defined by a vertical line and a horizontal line. The profile of the circular arc segment typically comprises a circular arc and a circular chord. The radius defining the circular arc is typically at most 20%, preferably at most 10%, particularly preferably at most 5% smaller than the inner radius of the hollow cylindrical magnet unit. The circular chord typically defines the side of the second shaped portion facing the examination object. The circular arc typically defines the side of the second shaped portion facing the magnet unit. Such a gradient coil unit particularly in the opposite arrangement of the first and second shaped portions separated by the cavity according to the application achieves a particularly good adaptation to the anatomy of the examination object, in particular when the examination region comprises the torso.

[0014] One embodiment of the gradient coil unit proposes that the circular arc of the first shape portion is horizontally oriented and that the first shape portion is arranged below the second shape portion. Preferably, the first shape portion is arranged below the cylinder axis and the second shape portion is arranged above the cylinder axis. According to this embodiment, the examination object can be arranged lying on the planar side of the first shape portion with the second shape portion arranged above the examination object. Thereby, the non-cylindrical gradient coil unit proposes a cavity whose horizontal extension perpendicular to the cylinder axis is larger than its vertical extension. This cavity is particularly well and comfortably suited for examination regions comprising the torso or limbs.

[0015] One embodiment of the gradient coil unit proposes that the second shape portion has a circular arc segment as a cross section perpendicular to the cylinder axis, which circular arc segment has a circular chord in the horizontal direction. Thereby, this non-cylindrical gradient coil unit provides a cavity which is bounded in the upper and lower part by two horizontal planes and in the side by the inner radius of the magnet unit. This cavity is particularly well and comfortably suited for examination regions comprising the torso or limbs.

[0016] One embodiment of the gradient coil unit proposes that the first shape portion has a greater arc height perpendicular to the cylinder axis than the second shape portion. The first arc height of the first shape portion is typically at least 10%, preferably at least 20%, more preferably at least 30% larger than the second arc height of the second shape portion. Thereby, the horizontal plane parallel to the cylinder axis defined by the first shape portion is at a smaller distance from the cylinder axis than the horizontal plane of the second shape portion. As long as the first arc height is smaller than the inner radius, the horizontal plane parallel to the cylinder axis defined by the first shape portion increases with increasing first arc height. The horizontal plane parallel to the cylinder axis defined by the first shape portion can define a support surface for the examination object. The larger the support surface, the higher the comfort for the examination object. Thereby, this embodiment achieves a particularly high comfort.

[0017] One embodiment of the gradient coil unit proposes that the second shape portion has a crescent cross section perpendicular to the cylinder axis. The crescent cross section generally has an outer circular arc and an inner circular arc. The radius defining the outer circular arc is generally up to 20 %, preferably up to 10 %, particularly preferably up to 5 % smaller than the inner radius of the hollow cylindrical magnet unit. The radius defining the inner circular arc is generally at least 5 %, preferably at least 10 %, particularly preferably at least 15 % larger than the inner radius of the hollow cylindrical magnet unit. The inner circular arc can also be described by an ellipse having a horizontal main axis. This gradient coil unit enables the examination object to be conveniently positioned on a horizontal plane defined by the first shape portion and the large cavity, which is defined in particular by the inner radius and can thus be largest for the defined magnet unit in the horizontal direction. The crescent shape also enables the height of the cavity and thus the examination region along the vertical line to be maximized, which can in particular contribute to preventing claustrophobia.

[0018] One embodiment of the gradient coil unit proposes that the circular chord of the first shape portion is oriented vertically, while the second shape portion has a circular arc segment as a cross section perpendicular to the cylinder axis, which has a circular chord in the vertical direction. This embodiment is particularly suitable when the spatial extension of the examination region and / or of the examination object surrounding the examination region in the vertical direction is not smaller than in the horizontal direction. In particular, this embodiment is advantageous if the examination region includes the head and / or has no shoulder region and / or no torso. The gradient coil unit laterally reduces the inner radius of the magnet unit, in particular at the ears of the head of the examination object, wherein the cavity and thus also the field of view are not limited along the vertical direction, i.e. from the field of view of the examination object upwards. This enables the geometry of the gradient coil unit to be ideally adapted to the shape of the head, whereby the examination object can be comfortably measured even in the case of a small inner radius of the magnet unit of, for example, 25 cm. In particular, this embodiment enables an unobstructed view of a screen positioned in front of the examination object, which enables comfortable entertainment and / or research in the field of functional MR imaging. According to this embodiment, the examination region is generally between 10 cm x 10 cm x 10 cm and 25 cm x 25 cm x 25 cm.

[0019] One embodiment of the gradient coil unit proposes that the first shape portion parallel to the cylinder axis has an upper edge that is longer than a lower edge. The second shape portion parallel to the cylinder axis preferably has an upper edge that is longer than a lower edge.

[0020] In the lying position, the shoulder region of the examination object has a greater horizontal extension and a smaller vertical extension than the neck and / or the head. If the first and / or second shape portion is shorter in the lower region, i.e. in the shoulder region, than in the upper region, a particularly good adaptation to the anatomy can be achieved. In particular, this increases the comfort and nevertheless achieves a good spatial coverage of the head. The upper edge and the lower edge of the first and / or second shape portion are preferably flush at the peripheral end of the gradient coil unit, i.e. at the end facing away from the examination object.

[0021] One embodiment of the gradient coil unit proposes that the projection of the first and / or second shape portion in a plane parallel to the cylinder axis is trapezoidal. The projection of the first and / or second shape portion in a plane parallel to the cylinder axis is preferably a right-angled trapezoid, wherein the upper edge and the lower edge of the first and / or second shape portion are preferably flush at the peripheral end. This embodiment can be realized particularly simply and cost-effectively.

[0022] One embodiment of the gradient coil unit proposes that the projection of the first and / or second shape portion in a plane parallel to the cylinder axis has a curvature between the upper edge and the lower edge on at least one side. The upper edge and the lower edge of the first and / or second shape portion are preferably flush at the peripheral end. Thus, the first and / or second shape portion can be particularly well adapted to the torso and / or shoulder region.

[0023] One embodiment of the gradient coil unit comprises a third conductor structure arranged within a third shape portion, wherein

[0024] The first conductor structure, the second conductor structure and the third conductor structure together constitute a magnetic field gradient generator for generating a magnetic field gradient along a first direction,

[0025] and the third shape portion has a circular arc segment as a cross section perpendicular to the cylinder axis, which circular arc segment has a circular chord in the horizontal direction.

[0026] The third conductor structure is generally surrounded and / or surrounded by the third shape portion. The third conductor structure can be embedded and / or injected into the third shape portion. The third conductor structure is generally spatially fixed by the third shape portion. The third shape portion can contain a resin and / or a plastic and / or at least one fiber reinforcement.

[0027] The third conductor structure can be constituted helically and / or saddle-like and / or constitute a segmented coil. The first conductor structure, the second conductor structure and the third conductor structure together preferably constitute a magnetic field gradient generator for generating a linear magnetic field gradient along a first direction. The first conductor structure, the second conductor structure and the third conductor structure can also together constitute a magnetic field gradient generator for generating a non-linear and / or indefinite magnetic field gradient, which is referred to in the specialist literature as Patloc and / or Flatloc.

[0028] The first and third shaped portions are preferably configured such that they intersect at right angles to their chords. The first and third shaped portions can overlap. The second and third shaped portions are preferably configured such that they intersect at right angles to their chords. The second and third shaped portions can overlap. The first, second, and third shaped portions preferably surround the inspection area from three sides. The inspection object is preferably positioned on and / or parallel to the horizontal plane of the third shaped portion. The first, second, and third shaped portions can be mutually non-intersecting. The first, second, and third shaped portions can form a unit together, particularly without intersecting surfaces. The first, second, and third conductor structures can be potted together, preferably by means of a potting compound such as resin. Then, the first, second, and third shaped portions can form an integral shape portion surrounding the first, second, and third conductor structures.

[0029] This implementation allows for a free field of view and makes good use of the cavity beneath the object being inspected, which is positioned in a flat position, for the third conductor structure. This enables the generation of a particularly precise magnetic field gradient while providing maximum comfort for the object being inspected.

[0030] One embodiment of the gradient coil unit proposes that the spatial extension of the first and / or second shaped portions parallel to the cylinder axis is less than the length of the magnet. This enables compact manufacturing and simple installation. In particular, the hollow region is occupied by the gradient coil unit to a minimum.

[0031] One embodiment of the gradient coil unit proposes that the gradient coil unit is axially symmetrical with respect to the vertical line along with the axis of the cylinder. This symmetry reflects the symmetry of the object being inspected. Furthermore, symmetrical gradient coil units can be designed and manufactured with particular simplicity. The gradient coil unit can also be axially symmetrical with respect to the horizontal line along with the axis of the cylinder, that is, it is also point-symmetrical with respect to the axis of the cylinder. In particular, the symmetry between the first and second shape portions makes the gradient coil unit particularly robust.

[0032] One embodiment of the gradient coil unit includes an electrical conductor and a connecting unit that connects the first conductor structure, the second conductor structure, and the gradient amplifier unit, wherein the connecting unit is disposed at the peripheral end of the magnet unit outside the cavity. This enables simple simultaneous manipulation of the first and second conductor structures, especially with the aid of conventional gradient amplifier units, without the cavity being limited by the electrical conductor or the connecting unit. The gradient coil unit can also include another gradient amplifier unit. The gradient amplifier unit can be connected to the first conductor structure, and / or the other gradient amplifier unit can be connected to the second conductor structure, and / or the first and second conductor structures can also be interconnected via a parallel circuit.

[0033] Furthermore, the application is based on a magnetic resonance device comprising a hollow-cylindrical magnet unit having an inner radius and a magnet length along the cylinder axis, and a gradient coil unit according to the application, wherein the gradient coil unit is arranged inside the inner radius of the magnet unit. The magnetic resonance device preferably comprises a radio frequency antenna unit for transmitting and receiving high-frequency signals and in particular magnetic resonance signals. Such a radio frequency antenna unit can be integrated into the gradient coil unit. Such a radio frequency antenna unit can be designed separately from the gradient coil unit, in particular as a local and combined transmit and receive coil. The radio frequency antenna unit preferably surrounds an examination region of an examination object at a distance of at most 20 cm, particularly preferably at most 7 cm. The embodiments of the magnetic resonance device according to the application are constituted analogously to the embodiments of the gradient coil unit according to the application. The magnetic resonance device can have further components for which the integration of the gradient coil unit is necessary and / or advantageous.

[0034] The advantages of the magnetic resonance device according to the application essentially correspond to the advantages of the gradient coil unit according to the application, which have been specified in detail above. The features, advantages or alternative embodiments mentioned in this context can likewise be transferred to the other claimed subject matters and vice versa. BRIEF DESCRIPTION OF DRAWINGS

[0035] Further advantages, features and details of the application result from the embodiments described hereinafter and by means of the drawings. The drawings show:

[0036] Figure 1 schematic diagram of a magnetic resonance device according to the application in a first embodiment is shown in a first view;

[0037] Figure 2 schematic diagram of a first embodiment of a gradient coil unit according to the application is shown in a second view;

[0038] Figure 3 schematic diagram of a second embodiment of a gradient coil unit according to the application is shown in a second view;

[0039] Figure 4 schematic diagram of a third embodiment of a gradient coil unit according to the application is shown in a second view;

[0040] Figure 5 schematic diagram of a magnetic resonance device according to the application in a second embodiment is shown in a first view;

[0041] Figure 6 schematic diagram of a fourth embodiment of a gradient coil unit according to the application is shown in a second view;

[0042] Figure 7 Fig. 1 shows a schematic view of a magnetic resonance apparatus according to the application in a first embodiment;

[0043] Figure 8 Fig. 5 shows a schematic view of a fifth embodiment of a gradient coil unit according to the application in a second view. DETAILED DESCRIPTION

[0044] Figure 1 A schematic view of a magnetic resonance apparatus 11 according to the application is shown. The magnetic resonance apparatus 11 comprises a magnet unit 17 for generating a strong and in particular constant main magnetic field 18. The magnet unit 17 is hollow-cylindrically constructed with an inner radius r i and a magnet length l m along the cylinder axis z m of the magnetic resonance apparatus 11. The magnetic resonance apparatus 11 further has a gradient coil unit 19 for position encoding during imaging. The gradient coil unit 19 is fitted into the region which is hollow-cylindrically surrounded by the magnet unit 17 with an inner radius r i .

[0045] The gradient coil unit 19 comprises a first conductor structure 41 arranged in a first shape portion 51 and a second conductor structure 42 arranged in a second shape portion 52, wherein the first conductor structure 41 and the second conductor structure 42 together are configured for generating a magnetic field gradient along a first direction. The first shape portion 51 and the second shape portion 52 are disjoint and arranged opposite to each other and separated by a cavity, in particular a patient receiving region 14. The first shape portion 51 has a circular arc segment as a cross section perpendicular to the cylinder axis z m .

[0046] According to this embodiment, a spatial extension of the first shape portion 51 and / or the second shape portion 52 parallel to the cylinder axis z m is shorter than the magnet length l m , and / or the gradient coil unit 19 is constructed axisymmetrically with respect to a vertical line together with the cylinder axis z m .

[0047] The gradient coil unit 19 can comprise electrical conductors 32 connecting the first conductor structure 41 with the second conductor structure 42 and a gradient amplifier unit 28 and / or a connection unit 33. The connection unit 33 is preferably arranged peripherally at a head end of the magnet unit 17. The gradient amplifier unit 28 can comprise a gradient control unit by means of which the gradient coil unit 19 is steerable.

[0048] Furthermore, the magnetic resonance apparatus 11 has a cylindrical patient receiving region 14 for accommodating the examination object 15, wherein the patient receiving region 14 is cylindrically surrounded in the peripheral direction by the magnet unit 17 and the gradient coil unit 19. The examination object 15 can be pushed into the patient receiving region 14 by means of a patient support device 16 of the magnetic resonance apparatus 11. To this end, the patient support device 16 has a patient table which is movably arranged within the magnetic resonance apparatus 11.

[0049] Furthermore, the magnetic resonance apparatus 11 has a radio frequency antenna unit 20 which in the case shown is embodied as a local, flexibly positionable body coil, and a radio frequency antenna control unit 29 for exciting polarization which occurs in the main magnetic field 18 generated by the magnet unit 17. The radio frequency antenna unit 20 is operated by the radio frequency antenna control unit 29 and radiates high-frequency pulses of high frequency into the examination room which is essentially formed by the patient receiving region 14.

[0050] The magnetic resonance apparatus 11 has a control unit 24 to control the magnet unit 17, the gradient amplifier unit 28 and the radio frequency antenna control unit 29. The control unit 24 centrally controls the magnetic resonance apparatus 11, for example, to execute MR control sequences. Furthermore, the control unit 24 has a reconstruction unit which is not shown in detail, for reconstructing medical image data detected during a magnetic resonance examination. The magnetic resonance apparatus 11 has a display unit 25. Control information, for example, control parameters as well as reconstructed image data can be displayed for a user on the display unit 25, for example, on at least one monitor. Furthermore, the magnetic resonance apparatus 11 has an input unit 26 by means of which information and / or control parameters can be input by a user during a measurement process. The control unit 24 can comprise the gradient amplifier unit 28 and / or the radio frequency antenna control unit 29 and / or the display unit 25 and / or the input unit 26.

[0051] Inner radius r i Typically between 22 cm and 38 cm, preferably between 25 cm and 35 cm, particularly preferably between 27 cm and 32 cm. Magnet length l m Typically between 70 cm and 110 cm, preferably between 80 cm and 100 cm, particularly preferably between 85 cm and 95 cm. Spatial extension of the first shape 51 and / or the second shape 52 parallel to the cylinder axis z m Typically between 35 cm and 70 cm, preferably between 40 cm and 60 cm, particularly preferably between 45 cm and 55 cm.

[0052] The illustrated magnetic resonance device 11 can obviously comprise further components which a magnetic resonance device 11 usually has. The general mode of functioning of a magnetic resonance device 11 is furthermore known to the person skilled in the art, so that the further components are not described in detail.

[0053] Figure 2 A schematic diagram of a first embodiment of a gradient coil unit 19 according to the application is shown in a second view. The second view is orthogonal to the first view, in particular perpendicular to the cylinder axis z m . According to this embodiment, the first shape portion 51 comprising the first conductor structure 41 has a circular arc segment as a cross section perpendicular to the cylinder axis z m . According to this embodiment, the circular chord of the first shape portion 51 is oriented horizontally and the first shape portion 51 is arranged below the second shape portion 52. According to this embodiment, the second shape portion 52 comprising the second conductor structure 42 has a circular arc segment as a cross section perpendicular to the cylinder axis z m , wherein the profile of the cross section has a circular arc with an inner radius r i and the circular chord of the circular arc segment is oriented along a horizontal direction. The sagittal height sagl of the first shape portion 51 perpendicular to the cylinder axis is preferably between 5 cm and 20 cm, in particular preferably between 10 cm and 15 cm. The sagittal height sag2 of the second shape portion 52 perpendicular to the cylinder axis is preferably between 5 cm and 20 cm, in particular preferably between 10 cm and 15 cm.

[0054] Figure 3 A schematic diagram of a second embodiment of a gradient coil unit 19 according to the application is shown in a second view. The second embodiment of a gradient coil unit 19 according to the application differs from the first embodiment in that the first shape portion 51 has a greater sagittal height sagl perpendicular to the cylinder axis than the second shape portion 52 with the sagittal height sag2.

[0055] Figure 4 A schematic diagram of a third embodiment of a gradient coil unit 19 according to the application is shown in a second view. The third embodiment of a gradient coil unit 19 according to the application differs from the first embodiment in that the second shape portion 52 has a crescent-shaped cross section perpendicular to the cylinder axis.

[0056] Figure 5 A schematic diagram of a magnetic resonance device 11 according to the application in a second embodiment is shown in a first view. The second embodiment of a magnetic resonance device 11 according to the application preferably differs from the first embodiment in its size, in particular with regard to the inner radius r i and / or the magnet length l mand / or the size of the patient accommodation region 14. The patient accommodation region 14 is preferably configured for accommodating a head region of the examination object 15 and not the whole body of the examination object 15. The inner radius r of the patient accommodation region 14 is also indirectly defined, in particular i is typically smaller than the inner radius in the first embodiment. In particular, the patient accommodation region 14 is preferably configured for accommodating a head of the examination object 15 and not its whole body.

[0057] The inner radius r of the second embodiment of the magnetic resonance apparatus 11 according to the application is typically between 18 cm and 35 cm, preferably between 20 cm and 31 cm, particularly preferably between 22 cm and 28 cm. i The magnet length l is typically between 40 cm and 90 cm, preferably between 50 cm and 80 cm, particularly preferably between 60 cm and 70 cm. The spatial extension of the first shape portion 51 and / or the second shape portion 52 parallel to the cylinder axis z is typically between 30 cm and 60 cm, preferably between 40 cm and 50 cm, particularly preferably between 42 cm and 48 cm. m The magnet length l is typically between 40 cm and 90 cm, preferably between 50 cm and 80 cm, particularly preferably between 60 cm and 70 cm. The spatial extension of the first shape portion 51 and / or the second shape portion 52 parallel to the cylinder axis z is typically between 30 cm and 60 cm, preferably between 40 cm and 50 cm, particularly preferably between 42 cm and 48 cm. m The magnet length l is typically between 40 cm and 90 cm, preferably between 50 cm and 80 cm, particularly preferably between 60 cm and 70 cm. The spatial extension of the first shape portion 51 and / or the second shape portion 52 parallel to the cylinder axis z is typically between 30 cm and 60 cm, preferably between 40 cm and 50 cm, particularly preferably between 42 cm and 48 cm.

[0058] The second embodiment of the magnetic resonance apparatus 11 according to the application differs from the first embodiment in that it comprises a gradient coil unit 19. According to this embodiment, the first shape portion 51 comprising the first conductor structure 41 comprised by the gradient coil unit 19 has a circular arc segment as a cross section perpendicular to the cylinder axis z. m According to this embodiment, the circular chord of the first shape portion 51 is oriented vertically.

[0059] According to this embodiment, the second shape portion 52 comprising the second conductor structure 42 comprised by the gradient coil unit 19 has a circular arc segment as a cross section perpendicular to the cylinder axis z. m According to this embodiment, the circular chord of the second shape portion 52 is oriented vertically. According to this embodiment, the profile of the cross section of the first shape portion 51 and the second shape portion 52 has a circular arc with an inner radius r. i

[0060] Preferably, the first shape portion 51 parallel to the cylinder axis has an upper edge which is longer than a lower edge. In particular, the projection of the first shape portion 51 in a plane parallel to the cylinder axis can be trapezoidal, in particular right-angled trapezoidal. The second embodiment of the magnetic resonance apparatus 11 according to the application typically also has the other features shown in Figure 1 , for example the radio frequency antenna unit 20, and other components which are typically important for the functional mode of the magnetic resonance apparatus 11 and known to the person skilled in the art. For the sake of overview, a detailed description and views of the other components are omitted. ​

[0061] Figure 6 A schematic diagram of a fourth embodiment of a gradient coil unit 19 according to the application is shown in a second view. The fourth embodiment of a gradient coil unit 19 according to the application differs from the first embodiment in that the chord of the first shape portion 51 and the chord of the second shape portion 52 are oriented vertically. Figure 5 The fourth embodiment of a gradient coil unit 19 according to the application can be shown in a first view. However, the fourth embodiment of a gradient coil unit 19 according to the application can also be designed such that the projection of the first shape portion 51 in a plane parallel to the cylinder axis is rectangular.

[0062] Figure 7 A schematic diagram of a magnetic resonance apparatus 11 according to the application in a third embodiment is shown in a first view. The third embodiment differs from the second embodiment of a magnetic resonance apparatus 11 generally in that the projection of the first shape portion 51 in a plane parallel to the cylinder axis z m , in particular in a vertical plane, has a curvature between an upper edge and a lower edge on at least one side, wherein the upper edge is preferably longer than the lower edge. Likewise, the projection of the second shape portion 52 in a plane parallel to the cylinder axis z m , in particular in a vertical plane, has a curvature between an upper edge and a lower edge on at least one side, wherein the upper edge is preferably longer than the lower edge.

[0063] Figure 8 A schematic diagram of a fifth embodiment of a gradient coil unit 19 according to the application is shown in a second view. The fifth embodiment of a gradient coil unit 19 differs from the fourth embodiment preferably in that it comprises a third conductor structure 43 arranged within a third shape portion 53.

[0064] The first conductor structure 41, the second conductor structure 42 and the third conductor structure 43 together constitute a magnetic field gradient generator for generating a magnetic field gradient along a first direction. The third shape portion 53 has a circular arc segment as a cross section perpendicular to the cylinder axis z m , which has a chord in a horizontal direction. The profile of the circular arc segment preferably comprises a circular arc having an inner radius r i . There can be an overlap of the third shape portion 53 with the first shape portion 51 and / or the second shape portion 52, wherein the overlap region preferably comprises less than 20%, in particular preferably less than 10%, of the third shape portion 53.

[0065] Although the details of the application have been illustrated and described by means of preferred embodiments, the application is not limited to the examples disclosed and other variants can be derived therefrom by a person skilled in the art without departing from the scope of protection of the application.

Claims

1. A gradient coil unit configured for fitting into a hollow cylindrical magnet unit of a magnetic resonance device, the magnet unit having an inner radius and a magnet length along a cylinder axis of the magnetic resonance device, the gradient coil unit comprising a first conductor structure arranged within a first shape portion, a second conductor structure arranged within a second shape portion, wherein the first conductor structure and the second conductor structure together are configured for generating a magnetic field gradient along a first direction, the first shape portion and the second shape portion are arranged non-intersectingly, opposite to each other and separated by a cavity, and the first shape portion has a circular arc segment as a cross section perpendicular to the cylinder axis, wherein a chord of the first shape portion is horizontally oriented and the first shape portion is arranged below the second shape portion, the second shape portion has a circular arc segment as a cross section perpendicular to the cylinder axis, the circular arc segment having a chord in horizontal direction, wherein the first shape portion has a greater arc height perpendicular to the cylinder axis than the second shape portion.

2. The gradient coil unit according to claim 1, wherein a profile of the cross section of the second shape portion perpendicular to the cylinder axis has a circular arc with an inner radius.

3. The gradient coil unit according to claim 1 or 2, wherein a spatial extension of the first shape portion and / or the second shape portion parallel to the cylinder axis is smaller than the magnet length.

4. The gradient coil unit according to claim 1 or 2, wherein the gradient coil unit is axisymmetric with respect to a vertical line together with the cylinder axis.

5. The gradient coil unit according to claim 3, wherein the gradient coil unit is axisymmetric with respect to a vertical line together with the cylinder axis.

6. A gradient coil unit configured for fitting into a hollow cylindrical magnet unit of a magnetic resonance device, the magnet unit having an inner radius and a magnet length along a cylinder axis of the magnetic resonance device, the gradient coil unit comprising a first conductor structure arranged within a first shape portion, a second conductor structure arranged within a second shape portion, wherein the first conductor structure and the second conductor structure together are configured for generating a magnetic field gradient along a first direction, the first shape portion and the second shape portion are arranged non-intersectingly, opposite to each other and separated by a cavity, and the first shape portion has a circular arc segment as a cross section perpendicular to the cylinder axis, wherein a chord of the first shape portion is vertically oriented, whereas the second shape portion has a circular arc segment as a cross section perpendicular to the cylinder axis, the circular arc segment having a chord in vertical direction, wherein the first shape portion has a longer upper edge than a lower edge parallel to the cylinder axis.

7. The gradient coil unit according to claim 6, wherein a projection of the first shape portion in a plane parallel to the cylinder axis is a trapezoid. ​ ​ ​ ​ ​ ​ ​ ​ 8. The gradient coil unit as defined in claim 6, wherein a projection of the first shaped portion in a plane parallel to the cylinder axis has a curvature between an upper edge and a lower edge on at least one side.

9. The gradient coil unit as defined in claim 7, wherein a projection of the first shaped portion in a plane parallel to the cylinder axis has a curvature between an upper edge and a lower edge on at least one side.

10. The gradient coil unit as defined in any one of claims 6 to 9, wherein a spatial extension of the first shaped portion and / or the second shaped portion parallel to the cylinder axis is smaller than the magnet length.

11. The gradient coil unit as defined in any one of claims 6 to 9, wherein the gradient coil unit is axisymmetric with respect to a vertical line together with the cylinder axis.

12. The gradient coil unit as defined in claim 10, wherein the gradient coil unit is axisymmetric with respect to a vertical line together with the cylinder axis.

13. A gradient coil unit configured for fitting into a hollow cylindrical magnet unit of a magnetic resonance device, the magnet unit having an inner radius and a magnet length along a cylinder axis of the magnetic resonance device, the gradient coil unit comprising a first conductor structure arranged within a first shaped portion, a second conductor structure arranged within a second shaped portion, wherein - the first conductor structure and the second conductor structure together are configured for producing a magnetic field gradient along a first direction, - the first shaped portion and the second shaped portion are arranged non-intersectingly, opposite to each other and separated by a cavity, and - the first shaped portion has a circular arc segment as a cross section perpendicular to the cylinder axis, wherein a chord of the first shaped portion is oriented vertically, and the second shaped portion has a circular arc segment as a cross section perpendicular to the cylinder axis, the circular arc segment having a chord in a vertical direction, wherein the gradient coil unit comprises a third conductor structure arranged within a third shaped portion, wherein the first conductor structure, the second conductor structure and the third conductor structure together are configured for producing a magnetic field gradient along a first direction, and the third shaped portion has a circular arc segment as a cross section perpendicular to the cylinder axis, the circular arc segment having a chord in a horizontal direction.

14. The gradient coil unit as defined in claim 13, wherein a spatial extension of the first shaped portion and / or the second shaped portion parallel to the cylinder axis is smaller than the magnet length.

15. The gradient coil unit as defined in claim 13 or 14, wherein the gradient coil unit is axisymmetric with respect to a vertical line together with the cylinder axis.

16. A magnetic resonance device comprising a hollow cylindrical magnet unit having an inner radius and a magnet length along a cylinder axis, and a gradient coil unit as defined in any one of claims 1 to 15, wherein the gradient coil unit is arranged inside the inner radius of the magnet unit.

Images