Magnetic resonance imaging device with concave field generating elements

Abstract

A magnetic resonance imaging device with a concave field generating unit is disclosed. The magnetic resonance imaging device (10) comprises a field generating unit (12) configured to provide a magnetic field in an imaging volume (30) of the magnetic resonance imaging device (10), wherein the field generating unit (12) comprises at least one magnet (13), and wherein a surface of the at least one magnet (13) oriented towards the imaging volume (30) comprises a concave shape, wherein an entry direction (16) to the imaging volume (30) is oriented substantially perpendicular to a main direction of magnetic field lines in the imaging volume (30).

Description

Technical Field

[0001] The present invention relates to a magnetic resonance imaging apparatus comprising a field generation unit configured to provide a magnetic field in an imaging volume of the magnetic resonance imaging apparatus, wherein the field generation unit comprises at least one magnet, and wherein the direction of entry into the imaging volume is oriented substantially perpendicular to the main direction of the magnetic field lines in the imaging volume. Background Technology

[0002] Magnetic resonance imaging (MRI) is a well-known imaging method used to acquire images of the interior of an object being examined. To perform MRI measurements, the object is typically positioned within a strong and homogeneous static magnetic field (B0 field) of the MRI apparatus. This static magnetic field can range in strength from 0.2 Tesla to 7 Tesla, causing the nuclear spins within the object to align along the field. To trigger so-called nuclear spin resonance, radio frequency (RF) excitation pulses are emitted into the object. Each RF pulse causes the nuclear spins within the object to magnetize, deviating from the static magnetic field by a certain amount, known as the flip angle. The RF pulses can include an alternating (electro) magnetic field whose frequency corresponds to a Larmor frequency at the given static magnetic field strength. The excited nuclear spins may exhibit rotating and decaying magnetization (nuclear magnetic resonance), which can be detected using a dedicated RF antenna. For spatial encoding of the measurement data, rapidly switching magnetic gradient fields are superimposed on the static magnetic field.

[0003] The received nuclear magnetic resonance (NMR) signals are typically digitized and stored as complex values ​​in a k-space matrix. This k-space matrix serves as the basis for reconstructing NMR images and determining spectral data. NMR images are usually reconstructed using a multidimensional Fourier transform of the k-space matrix.

[0004] During imaging examinations, patients are typically enclosed within the aperture or a pair of magnets of an MRI scanner. Due to the limited space within the area between the aperture or magnet pair, MRI offers limited use for surgical procedures or biopsies. Because the patient needs to be positioned inside the MRI scanner, the aperture size, as well as other dimensions of the scanner, are determined by the size of the human body. This can be unsatisfactory from a cost and / or space utilization perspective, especially if the examination is limited to a body area significantly smaller than the imaging volume provided by the MRI scanner. Furthermore, children and patients with claustrophobic conditions may not tolerate prolonged periods of confinement within the restricted imaging space associated with conventional MRI scanners. Summary of the Invention

[0005] Therefore, the object of the present invention is to provide a magnetic resonance imaging device with enhanced openness and / or accessibility for imaging specific body regions of a patient.

[0006] This objective is achieved by the magnetic resonance imaging apparatus according to the present invention. Further advantageous embodiments are described in detail in the technical solution of the present invention.

[0007] The magnetic resonance imaging apparatus of the present invention includes a field generation unit configured to provide a magnetic field in the imaging volume of the magnetic resonance imaging apparatus, wherein the field generation unit includes at least one magnet.

[0008] The field generation unit may include one or more magnets required to perform magnetic resonance measurements. For example, the field generation unit may include at least one magnet configured to generate a static magnetic field within the imaging volume of a magnetic resonance imaging apparatus. The static magnetic field may be the main magnetic field and / or the BO field of the magnetic resonance imaging apparatus. The static magnetic field may include a substantially uniform magnetic field or a predetermined magnetic gradient field. In another example, the field generation unit includes at least one gradient coil for generating a temporary magnetic gradient field within the imaging volume. It is also conceivable that the field generation unit includes at least one radio frequency (RF) antenna for transmitting RF excitation pulses within the power and frequency range of the magnetic resonance measurements to the image acquisition area of ​​the magnetic resonance imaging apparatus. The at least one RF antenna may also be configured to receive magnetic resonance signals (NMR) from the image acquisition area. In one embodiment, at least one magnet may be configured as a main magnet for generating a static magnetic field within the imaging volume. However, at least one magnet may also correspond to a gradient coil, a group of gradient coils, and / or an RF antenna of the magnetic resonance imaging apparatus.

[0009] The imaging volume can be characterized by a predefined magnetic field direction and / or a predefined magnetic field strength. For example, the imaging volume may include a volume with a substantially uniform magnetic field direction and / or magnetic field strength. Such a volume may be isocenter of a magnetic resonance imaging (MRI) device. It is also conceivable that the imaging volume includes a predefined magnetic gradient field. Such a magnetic gradient field can be used to spatially encode magnetic resonance signals acquired from an object located within the imaging volume.

[0010] At least one surface of the magnet oriented toward the imaging volume includes a concave shape.

[0011] The surface of at least one magnet oriented toward the imaging volume can be a pole face of the at least one magnet. The pole face can be characterized by a terminating surface of the at least one magnet. It is conceivable that the magnetic field strength is particularly high at the pole face of the at least one magnet. The pole face can also represent the side of the at least one magnet oriented toward or away from the imaging volume orientation. In the case of a permanent magnet, the pole face can be a terminating surface of the north and / or south poles. In particular, the surface of the at least one magnet oriented toward the imaging volume can relate to the surface of the magnetic material of the at least one magnet. In the case where the at least one magnet comprises resistance wire or superconducting wire, the pole face can relate to a surface that circumferentially surrounds the magnet as an imaginary film, imaginary envelope, or imaginary envelope curve.

[0012] The surface of at least one magnet oriented toward the imaging volume can be shaped such that the perpendicular distance between a line oriented along the principal direction of the magnetic field lines within the imaging volume and the surface of the at least one magnet oriented toward the imaging volume varies along the principal direction of the magnetic field lines. It is conceivable that the surface of the at least one magnet oriented toward the imaging volume is characterized by an arc or an ellipse. For example, the surface oriented toward the imaging volume can include a "U" shape or a "C" shape. In one embodiment, the imaging volume is positioned within a recess or depression provided by the concave surface of the at least one magnet oriented toward the imaging volume. The cross-section of the recess or depression can include the shape of a parabola, a hyperbola, or a portion of an ellipse or circle. In one embodiment, the topology or shape of the at least one magnet can correspond to a saddle. The at least one magnet can be designed to accommodate the pelvic region of a patient sitting on the surface of the at least one magnet oriented toward the imaging volume. According to another embodiment, the at least one magnet can include the shape of a curved beam or a hyperboloid. The curved beam can be oriented along the sagittal plane of a patient sitting on the surface of the at least one magnet oriented toward the imaging volume. Within the meaning of this invention, the shapes of 'U', 'C', and / or curved beams can be considered as saddle shapes. In one embodiment, the surface of at least one magnet oriented toward the imaging volume may include a concave shape along the anterior-posterior direction of the patient and a convex shape along the lateral direction of the patient. However, at least one magnet may also be designed to accommodate other body areas of the patient, such as the facial area, head area, limbs, breast area, etc.

[0013] The direction of entry into the imaging volume is oriented to be substantially perpendicular to the main direction of the magnetic field lines in the imaging volume.

[0014] The direction of entry to the imaging volume can be characterized by a basic straight line leading from any point in the environment (particularly the examination room) to the center of the imaging volume. Preferably, the trajectory defined by the line is not obstructed by components of the magnetic resonance imaging equipment. The direction of entry relates to the trajectory along which the patient can enter the imaging volume.

[0015] At least one magnet can restrict the imaging volume in at least one spatial direction in such a way that approaching or entering the imaging volume from a direction substantially corresponding to at least one spatial direction is impractical or impossible. For example, at least one magnet can prevent or block entry into the imaging volume in any direction oriented parallel to the principal direction of the magnetic field lines in the imaging volume. At least one magnet preferably provides entry into the imaging volume along at least two perpendicular spatial directions. The two perpendicular spatial directions can be oriented substantially perpendicular to the principal direction of the magnetic field lines in the imaging volume. The principal direction of the magnetic field lines in the imaging volume can be characterized by the average or mean direction of a plurality of magnetic field vectors within the imaging volume.

[0016] In one embodiment, the magnetic resonance imaging apparatus of the present invention includes a support structure configured to provide structural support to a field generation unit. The support structure may include a positioning unit configured to adjust the position and / or orientation of the field generation unit in at least one or at least two spatial directions. Specifically, the positioning unit may be configured to position the field generation unit along one axis or along two perpendicular axes of a Cartesian coordinate system. Preferably, the positioning unit is configured to position the field generation unit along three perpendicular axes of a Cartesian coordinate system. For example, the positioning unit may include a track system and / or a telescope system configured to transport the field generation unit along a predetermined trajectory.

[0017] The positioning unit may also include hinges and / or movable joints configured to adjust the orientation of the field generating unit. For example, the positioning unit may be configured to adapt the position and / or orientation of the field generating unit relative to the patient's target anatomical structure. When the field generating unit is positioned and / or oriented relative to the patient, the patient may be stationary in a predetermined posture, such as supine, sitting, or standing. Adjustment of the position and / or orientation of the field generating unit may involve adjusting the position of the imaging volume to cover at least a portion of the patient's target anatomical structure. The patient may also be placed on a patient positioning device configured to position the patient in a desired relative position and / or orientation relative to the magnetic resonance imaging apparatus. When providing the positioning unit, the position of the imaging volume of the magnetic resonance imaging apparatus can be advantageously adapted to cover the target anatomical structure of an immobile or disabled patient.

[0018] In another embodiment, the magnetic resonance imaging apparatus of the present invention may include a stray field containment unit configured to align the magnetic stray field of the field generation unit in such a way that the magnetic field strength and / or magnetic field uniformity at the center of the imaging volume is increased.

[0019] In one embodiment, the stray field containment unit includes a backplate attached to at least one magnet, wherein the backplate comprises a ferromagnetic material, and wherein the backplate is attached to a surface of the at least one magnet oriented away from the imaging volume. Preferably, the backplate completely surrounds or covers the surface of the at least one magnet oriented away from the imaging volume. In another embodiment, the stray field containment unit includes a yoke attached to at least one magnet, wherein the yoke comprises a ferromagnetic material. Examples of ferromagnetic materials include iron, cobalt, nickel, as well as lanthanides, gadolinium, etc. The ferromagnetic material can be deployed as a solid material or a fluid. In a preferred embodiment, the backplate and / or yoke are made of iron, iron alloys, or any other material with high magnetic permeability.

[0020] The yoke can represent at least a portion of the support structure. Therefore, the yoke can provide structural support to the field generation unit and / or maintain a predetermined shape for at least one magnet. Specifically, the yoke can be configured to counteract the magnetic attraction forces of multiple segments of the at least one magnet. It is conceivable that the yoke is attached to a surface of the at least one magnet oriented away from the imaging volume. The yoke and / or backplate can include concave shapes to match the concave surfaces of the at least one magnet oriented away from the imaging volume. In a preferred embodiment, the backplate and / or yoke serve as the support structure according to the above embodiments. In particular, the support structure, backplate, and / or magnetic yoke can be designed to enhance, confine, or shape the magnetic field of the magnetic resonance imaging apparatus of the present invention. When providing a stray field containment unit according to the above embodiments, alignment of the magnetic stray field can be advantageously achieved without restricting or impairing the accessibility of the imaging volume. As another advantage, the characteristics of the magnetic field within the imaging volume can be advantageously improved.

[0021] In another embodiment, the stray field containing unit further includes a shielding coil configured to align with the magnetic stray field of the field generating unit in a manner that increases the magnetic field strength and / or magnetic field uniformity at the center of the imaging volume. The shielding coil advantageously comprises one or more coils (which are wires) arranged in a curved surface corresponding to a concave shape of a surface of at least one magnet oriented toward the imaging volume. In a preferred embodiment, the shielding coil is positioned adjacent to the surface of at least one magnet oriented toward the imaging volume.

[0022] When at least one magnet with a concave surface oriented toward the imaging volume is provided, the openness of the field generation unit can be advantageously enhanced compared to conventional magnetic resonance imaging (MRI) devices. Therefore, access to the imaging volume can be facilitated while still providing sufficient coverage of the patient's diagnostically relevant body regions with magnetic material. In particular, the MRI device of the present invention can provide easy and / or optimized access to specific body regions of the patient to the imaging volume with limited trade-offs regarding image quality and / or image acquisition time. Another advantage of the MRI device of the present invention compared to conventional MRI devices can be comprised of reduced cost and / or weight.

[0023] According to one embodiment of the magnetic resonance imaging apparatus of the present invention, at least one magnet is designed to provide access to the imaging volume along at least two vertical spatial directions, wherein each of the two vertical spatial directions is oriented substantially perpendicular to the main direction of the magnetic field lines in the imaging volume.

[0024] For example, the imaging volume can be at least partially embedded within a recess or depression provided by a concave surface oriented toward the imaging volume via at least one magnet. In a preferred embodiment, the at least one magnet comprises a curved beam shape that at least partially surrounds the imaging volume along a trajectory defined by the concave surface oriented toward the imaging volume. The curved beam may include an arched profile or contour that at least partially surrounds the imaging volume. Preferably, the at least one magnet surrounds the imaging volume substantially along an arc of a cross-section of an imaginary sphere, wherein the center and volume of the imaginary sphere correspond to the center and volume of the imaging volume. Thus, it is advantageous to be accessible from at least two directions oriented perpendicular to the main direction of the magnetic field lines within the imaging volume. In an alternative embodiment, the surface of the at least one magnet oriented toward the imaging volume may also comprise a more three-dimensional shape, such as the inner surface of a cone or hemisphere. Thus, the at least one magnet may surround a large portion of the surface of the imaging volume. It is conceivable that a maximum of 75%, 60%, 45%, or 30% of the outer surface of the imaging volume is surrounded by at least one magnet.

[0025] By providing access to the imaging volume along at least two vertical spatial directions, multiple modes of access to the imaging volume can be provided to the patient. Therefore, the maximum number of body regions of a patient that can be imaged via the magnetic resonance imaging apparatus of the present invention can be advantageously increased. By providing multiple modes and / or directions of access to the imaging volume, different groups of patients (e.g., children, the elderly, and / or disabled persons) can advantageously access the imaging volume in the most comfortable manner.

[0026] In another embodiment of the magnetic resonance imaging device of the present invention, the shape of the imaging volume is adapted to the shape of the patient's target anatomical structure.

[0027] At least one magnet can be shaped to form an imaging volume that is non-spherical. Preferably, at least one magnet is shaped such that the shape of the imaging volume corresponds to the shape of the patient's target anatomical structure. The target anatomical structure may include, for example, the jaw region, jaw, eye region, eye, part of the spine, prostate, heart, brain, or other organs or anatomical structures. In particular, at least one magnet can be shaped such that the imaging volume provided via at least one magnet can take into account variations in the anatomical size, shape, and / or orientation of the target anatomical structure. For example, at least one magnet can be adapted to key variation parameters of the target anatomical structure. Thus, when the patient is correctly positioned relative to the magnetic resonance imaging apparatus of the present invention, the shape of the imaging volume provided via at least one magnet may differ from the actual shape of the target anatomical structure, but completely cover the target anatomical structure. It is also conceivable that the imaging volume provided via at least one magnet reduces the volume of any tissue that differs from the tissue of the target anatomical structure. Thus, the time required to perform magnetic resonance measurements of the target anatomical structure using the magnetic resonance imaging apparatus of the present invention can be advantageously reduced. In one embodiment, the imaging volume includes a disk-shaped, star-shaped, elliptical, oval, polyhedral shape, or any combination of these shapes.

[0028] Providing an imaging volume with a shape suitable for matching the target anatomical structure can advantageously facilitate and / or simplify the process of preparing magnetic resonance measurements. Furthermore, providing a field generation unit suitable for accommodating the target anatomical structure at a predetermined relative position can advantageously improve the efficiency of preparing and / or performing magnetic resonance measurements.

[0029] In another embodiment of the magnetic resonance imaging device of the present invention, at least one magnet is designed to accommodate a patient in a seated position on a surface oriented toward the imaging volume, wherein at least one magnet includes at least one recess configured to accommodate the legs of the patient positioned in a seated position.

[0030] In a preferred embodiment, the magnetic resonance imaging device of the present invention is a dedicated prostate scanner configured to acquire magnetic resonance signals from a patient's prostate region. For this purpose, the patient can sit on a surface oriented towards the imaging volume of at least one magnet. One of the patient's legs can be adjacent to at least one magnet from a first side, and the patient's second leg can be adjacent to at least one magnet from a second side different from the first side. Preferably, the first and second sides are oriented away from the imaging volume. The first and second sides can be oriented in substantially opposite spatial directions. It is conceivable that the first side of at least one magnet includes a first recess configured to accommodate one leg. The second side of at least one magnet may include a second recess configured to accommodate the patient's second leg. The shapes of the first and second recesses can substantially correspond to the shape and / or contour of the patient's leg. Preferably, the first and / or second recesses of at least one magnet are designed such that the angle and / or distance between the thigh of one leg and the thigh of the second leg of the patient sitting on the imaging volume-oriented surface of at least one magnet is reduced compared to embodiments without recesses. Of course, the first and second recesses can be designed as depressions within at least one magnet. The patient's sitting posture can correspond to the correct posture for performing magnetic resonance imaging measurements of the prostate.

[0031] When a recess or indentation is provided to accommodate the patient's legs, strain associated with expanding the patient's legs can be advantageously reduced or eliminated when the patient sits on the magnetic resonance imaging apparatus of the present invention for performing magnetic resonance measurements.

[0032] According to one embodiment, the magnetic resonance imaging apparatus of the present invention further includes a positioning aid configured to support the patient in the correct posture for performing magnetic resonance imaging measurements.

[0033] Positioning aids can be configured to support specific body regions of a patient. For example, positioning aids can be configured as footrests, backrests, headrests, armrests, handles, cushions, etc. According to one embodiment, the positioning aid surrounds at least a portion of the contour of the patient's body region. Therefore, the patient can be supported in three dimensions. The positioning aid can provide passive support to help the patient assume and / or maintain a correct posture. However, the positioning aid may also include an adjustment unit configured to actively adjust the position and / or orientation of the positioning aid relative to at least one magnet. The adjustment unit can allow the operator and / or patient of the magnetic resonance imaging device of the present invention to manually adjust the positioning aid. However, the adjustment unit may also include a actuator adapted to automatically adapt the position and / or orientation of the positioning aid. It is conceivable that the adjustment unit can be remotely controlled by the operator of the magnetic resonance imaging device of the present invention. Therefore, specific body regions or multiple specific body regions of the patient can be guided, positioned, and / or supported by controlling the position and / or orientation of the positioning aid. Preferably, the positioning aid supports specific body regions or multiple specific body regions of the patient in a manner that allows the patient to assume a correct posture.

[0034] Correct posture is characterized by a predefined relative position between the patient and the magnetic resonance imaging device, wherein when the patient is positioned in the correct posture, at least a portion of the patient’s diagnostically relevant body region is covered by the imaging volume.

[0035] For example, when the patient is positioned in the correct posture, the patient's prostate, jaw region, eye region, brain, or other target anatomical structures can be positioned within the imaging volume. The positioning aid can support the patient in a manner that maintains the relative position of the target anatomical structure and the magnetic resonance imaging apparatus of the present invention during magnetic resonance measurements through the target anatomical structure. However, the positioning aid can also be configured to align the position of the target anatomical structure with the position of the imaging volume during preparation for the magnetic resonance measurement. It is also conceivable that the positioning aid includes an adjustment unit that allows the patient and / or operator to align the position of the target anatomical structure with the position of the imaging volume.

[0036] Compared to conventional magnetic resonance imaging (MRI) devices, the MRI device of the present invention can provide significantly increased accessibility, thus increasing the risk of patient movement during MRI measurements. Providing positioning aids can advantageously restrict patient movement during MRI measurements, thereby improving the imaging quality of the MRI device of the present invention. Furthermore, the positioning aids advantageously facilitate and / or accelerate the process of matching the position of the target anatomical structure with the imaging volume of the MRI device of the present invention.

[0037] In a preferred embodiment, the positioning aid includes an adjustment unit and a processing unit, wherein the adjustment unit is configured to adjust the position and / or orientation of the positioning aid relative to at least one magnet, and wherein the processing unit is configured to receive patient information and control the adjustment unit to adapt the position and / or orientation of the positioning aid according to the patient information.

[0038] The processing unit may be the main processing unit of the magnetic resonance imaging apparatus of the present invention, configured to process magnetic resonance image data and / or reconstruct magnetic resonance images acquired during magnetic resonance measurement. However, the processing unit may also be separate from the main processing unit and / or include signal connections enabling communication with the main processing unit. The processing unit may be integrated within the control unit of the magnetic resonance imaging apparatus according to the present invention.

[0039] As described above, the adjustment unit may include a driver configured to adapt to the position and / or orientation of the positioning aid. Preferably, the processing unit may be configured to acquire patient information from a source and to automatically adapt the orientation and / or position of the positioning aid based on the acquired patient information by controlling the adjustment unit. The source may be a user interface, a radiology information system, a hospital information system, an internal or external storage unit, an electronic patient register, etc. The patient information may include any information about the patient in relation to the performance of the magnetic resonance imaging (MRI) measurement. For example, patient information may include information about age, weight, body size, sex, medical history, treatment duration, target anatomy, and other information about the patient.

[0040] When an adjustment unit and a processing unit are provided that are configured to automatically adjust the position and / or orientation of the positioning aid based on patient information, the patient can be advantageously positioned in the correct posture in a reproducible and / or robust manner. Furthermore, the time required to position the patient in the correct posture can be advantageously reduced.

[0041] According to another embodiment of the magnetic resonance imaging apparatus of the present invention, at least one surface of a magnet oriented toward the imaging volume is shaped to match the contour of a patient's body region, wherein the patient's body region includes at least one of the following:

[0042] o Spine region

[0043] o Facial area,

[0044] pelvic region

[0045] o breast area,

[0046] o Abdominal region,

[0047] limbs.

[0048] The contour of the patient's body region may be at least a segment of the circumference of an axial section of the patient's body or body part. For example, the contour of the patient's body region may be characterized by a segment of the contour line of an axial section of the patient's breast region, facial region, abdominal region, or limb (e.g., thigh or arm). The surface of at least one magnet oriented toward the imaging volume may correspond to the contour line of the patient's body region. Preferably, at least one magnet is shaped to resemble a saddle, matching the contour of the pelvic region of a patient sitting in the correct posture on at least one magnet. However, at least one magnet may also include a 'U' or 'C' shape configured to match the contour of the patient's facial region and / or other body regions.

[0049] By matching the shape of the surface of at least one magnet oriented toward the imaging volume to the contour of the patient's body region, the distance between at least one magnet and the patient's body surface can be advantageously reduced when the patient is positioned in the correct posture. Therefore, the cost and / or space requirements associated with providing a magnetic field and / or magnetic gradient field configured to operate at a higher distance from the patient can be advantageously reduced.

[0050] According to one embodiment of the magnetic resonance imaging apparatus of the present invention, the surface of at least one magnet oriented toward the imaging volume is shaped to match the contour of the patient's pelvic region and is designed to accommodate the patient in a seated position, wherein, when the patient is positioned in a seated position, at least a portion of the patient's prostate and / or lymph nodes adjacent to the prostate are positioned within the imaging volume.

[0051] As described above, at least one magnet can be shaped to resemble a saddle, matching the contour of the pelvic region of a patient sitting in the correct posture on the at least one magnet. The concave surface of the at least one magnet oriented towards the imaging volume can be shaped such that the pelvic region of the patient sitting on the at least one magnet automatically slides into the lowest region of the at least one magnet, thereby positioning at least a portion of the prostate within the imaging volume. The lowest region can be characterized by a recess and / or lowest segment of the concave surface of the at least one magnet oriented towards the imaging volume relative to the floor of the examination room. For example, the recess can be characterized by the minimum vertical distance between the surface of the at least one magnet oriented towards the imaging volume and the substantially flat surface of the examination room floor. It is also conceivable that at least one recess configured to accommodate the patient's legs supports the patient in adopting and / or maintaining the correct posture for performing MRI measurements of the patient's prostate and / or lymph nodes. In a preferred embodiment, the patient can adopt the correct posture when seated on the surface of the at least one magnet oriented towards the imaging volume. For this purpose, the patient can be supported by a positioning aid according to the above embodiment.

[0052] When a saddle magnet is provided, it can advantageously support the patient in adopting and / or maintaining the correct posture for magnetic resonance imaging (MRI) measurements. Furthermore, a saddle magnet designed to accommodate a sitting position can advantageously facilitate access to the imaging volume, particularly for the elderly or disabled, and / or allow children to maintain eye contact with their parents during MRI measurements.

[0053] According to one embodiment of the magnetic resonance imaging apparatus of the present invention, the field generation unit further includes an adjustment mechanism configured to adjust the position and / or orientation of at least a portion of the field generation unit and modify the properties of the magnetic field provided via the field generation unit, wherein the properties of the magnetic field include at least one of the shape of the imaging volume, the position of the imaging volume, the magnetic field strength and / or the direction of the magnetic field lines.

[0054] In a preferred embodiment, the adjustment mechanism may form part of a support structure attached to the field generation unit. The support structure may be configured according to the embodiments described above. For example, the adjustment mechanism may form part of a positioning unit. The positioning unit may be configured to modify the position and / or orientation of the field generation unit, thereby changing the position and / or orientation of the imaging volume. However, the adjustment mechanism may also be configured to modify the geometric arrangement of the field generation unit or components of the field generation unit, such as magnets, radio frequency antennas, gradient coils, shielding coils, yokes, backplates, etc. In particular, the adjustment mechanism may be configured to adjust the position and / or orientation of a magnet configured to provide and / or modify a static magnetic field within the imaging volume. The term imaging volume should be interpreted as a volume having approximately uniform magnetic field properties, rather than the sampling volume of the radio frequency antenna.

[0055] According to one embodiment, the adjustment mechanism includes a magnet (e.g., a permanent magnet, an electromagnet, and / or a superconducting magnet) configured to provide a secondary magnetic field or mechanically connected to a magnet configured to provide a secondary magnetic field. The secondary magnetic field can modify the properties of the magnetic field when the relative position between the field generating unit and the magnet changes and / or when current is fed through the magnet. The magnet can be positioned relative to other components of the field generating unit to modify the properties of the magnetic field, such as magnetic field strength, the orientation of magnetic field lines, and / or the shape of the imaging volume. For this purpose, the adjustment mechanism may include gears and / or mechanisms adapted to adjust the position and / or orientation of at least a portion of the field generating unit. The adjustment mechanism can be adjusted manually and / or automatically. For example, the adjustment mechanism can be adjusted by an actuator controlled via a processing unit of a magnetic resonance imaging device. However, the adjustment mechanism may also allow manual adjustment, for example, via a handle or joystick.

[0056] In a preferred embodiment, the adjustment mechanism includes an electromagnet comprising at least one resistance coil or at least one superconducting magnet, the at least one superconducting magnet comprising at least one superconducting coil, the at least one resistance coil or at least one superconducting coil being configured to generate a magnetic field when current is fed through the at least one resistance coil or at least one superconducting coil. In one example, the properties of the magnetic field can be modified by adjusting the position of the electromagnet or superconducting magnet relative to other components of the field generating unit. However, the properties of the magnetic field can also be modified by feeding current through the electromagnet or superconducting magnet.

[0057] When no current is applied to the electromagnet or superconducting magnet, the relative position between the electromagnet or superconducting magnet and other components of the field generating unit can be advantageously adjusted without having to overcome magnetic attraction. When providing the adjustment mechanism, the properties of the magnetic field provided via the field generating unit can be advantageously modified to match the position and / or shape of the patient's target anatomical structures.

[0058] In one embodiment of the magnetic resonance imaging device of the present invention, at least one magnet includes at least one of the following:

[0059] o permanent magnet,

[0060] Array of permanent magnets

[0061] o Resistor coil,

[0062] an array of resistor coils,

[0063] o High-temperature superconductor

[0064] o Low temperature superconductor, and

[0065] The surface of at least one magnet (13) oriented toward the imaging volume (30) corresponds to the pole face of at least one magnet (13) and / or the surface of the material of at least one magnet (13) configured to provide a magnetic field.

[0066] Permanent magnets can include magnetic materials such as AlNiCo (AlNiCo), NeFeB (Nedymium Iron Boron), or SmCo (Samarium Cobalt) alloys. Permanent magnets can include any desired shape. In one embodiment, the permanent magnet comprises a rod shape. The rod shape can include a cuboid rod shape, a cylindrical rod shape, or a rod shape with a polygonal cross-section, such as a prism. The rod-shaped permanent magnet can be bent to provide a concave surface oriented towards the imaging volume. The rod-shaped permanent magnet provides a low-cost solution for generating a magnetic field within the imaging volume. In another embodiment, the permanent magnet can consist of smaller stacked permanent magnets or an array of permanent magnets. The array of permanent magnets can include multiple magnets with variable magnetic field strength and / or magnetic orientation. In particular, the array of permanent magnets can be configured as a Halbach array. Using permanent magnets can advantageously avoid the cost and space required for cooling equipment typically associated with superconducting magnets and electromagnets.

[0067] At least one magnet may also be an electromagnet. The electromagnet may be a non-superconducting magnet. Specifically, the electromagnet may comprise a resistance coil (e.g., an electrical conductor) wound around a magnetic core made of, for example, a ferromagnetic or ferrimagnetic material. The axial cross-section of the magnetic core may include a cylindrical, cubic, prismatic, or any other desired shape. However, the magnetic core may be omitted. The resistance coil may be wound in a manner that provides a concave surface oriented toward the imaging volume. For this purpose, the resistance coil may be wound in a curved surface that corresponds in shape to the concave surface of the at least one magnet oriented toward the imaging volume. However, the resistance coil may also comprise a winding pattern extending through the three-dimensional volume of the at least one magnet. In another embodiment, the electromagnet comprises an array of resistance coils. It is also contemplated that the array of resistance coils be configured as a Hellbeck array. By using an electromagnet, the magnetic field strength can be advantageously increased compared to a permanent magnet of comparable size. A higher magnetic field strength can advantageously improve the quality and / or signal-to-noise ratio of magnetic resonance images acquired via the magnetic resonance imaging apparatus of the present invention.

[0068] A superconductor may include a coil of superconducting wire and / or magnetic segments of superconducting material. The superconductor may be a low-temperature superconductor or a high-temperature superconductor connected to a cryostat to maintain the superconductor's temperature below a predetermined value. Similar to resistance wire, the coil of the superconducting wire may be arranged to provide a concave surface oriented toward the imaging volume. The superconducting wire may be embedded in an electrical conductor (e.g., copper, gold, silver, etc.). However, a superconductor may also include one or more bulk magnetic segments made of superconducting material. Preferably, the magnetic segments form a concave surface oriented toward the imaging volume.

[0069] Low-temperature superconductors can include superconducting properties at temperatures around 4 K, while high-temperature superconductors can include superconducting properties in the range of 30 K to 90 K. Examples of high-temperature superconductors are barium copper oxides (e.g., YBCO, ReBCO), calcium copper oxides (e.g., BSCCO), and doped fullerenes (e.g., Cs₂RbC₂). 60 Examples of low-temperature superconducting materials include niobium-titanium alloys, niobium-tin alloys, and magnesium diboride. Compared to low-temperature superconductors, the efficiency of a cryostat configured for cooling at least one magnet can be advantageously improved when using high-temperature superconductors. Low-temperature superconductors are also cheaper and easier to handle. The magnetic field strength can be advantageously increased by using superconducting magnets compared to permanent magnets or electromagnets of equivalent size.

[0070] In particular, in the case of an electromagnet or a superconducting magnet, the surface of at least one magnet oriented toward the imaging volume can be characterized by a surface that circumferentially surrounds the resistance coil or superconducting wire, or a surface with a virtual envelope curve. Therefore, the term "the surface of at least one magnet oriented toward the imaging volume" can refer to the surface surrounding the virtual envelope of the electromagnet or superconducting magnet.

[0071] In another embodiment of the magnetic resonance imaging apparatus according to the invention, the surface of at least one magnet oriented toward the imaging volume includes a hole, wherein the hole is configured to provide access from the side of the at least one magnet away from the imaging volume orientation to the imaging volume.

[0072] The aperture can be designed in a manner that provides an unobstructed view through the magnetic resonance imaging apparatus of the present invention, enhances airflow to the imaging volume, and / or provides access to the imaging volume for interventional and / or therapeutic instruments. For example, the aperture can provide a gap for positioning a rectal coil when a patient is positioned correctly on the surface of at least one magnet oriented toward the imaging volume. However, the aperture can also provide a gap for positioning an intraoral coil when the patient's facial region is positioned within the imaging volume. Of course, other medical instruments associated with intervention and / or therapy can be guided through the aperture of at least one magnet. In cases where at least one magnet comprises an electromagnet or a superconductor, a resistive coil or superconducting wire can be wired around the aperture of at least one magnet. In one example, the aperture can comprise a cylindrical shape. However, the aperture can also comprise a conical and / or tapered shape. The axial cross-section of the aperture can be circular, elliptical, or polygonal.

[0073] When providing the aperture according to the above embodiments, the medical device and / or apparatus can advantageously be introduced from the back of at least one magnet. Therefore, the success rate of interventions or treatments accompanying magnetic resonance measurements and the image quality of the magnetic resonance imaging equipment can be advantageously enhanced. Furthermore, during magnetic resonance measurements of the patient's facial region and / or head, the aperture can provide an unobstructed view through at least one magnet. Therefore, it allows the patient to maintain eye contact with others in the examination room, reducing the risk of interrupting the magnetic resonance measurement due to discomfort.

[0074] In one embodiment of the magnetic resonance imaging apparatus of the present invention, the field generation unit includes a gradient field system comprising at least one gradient coil configured to provide a magnetic gradient field within the imaging volume.

[0075] A gradient field system may include at least one gradient coil, at least two gradient coils, or at least three gradient coils. Preferably, at least one gradient coil is configured to generate a magnetic gradient field within the imaging volume. The magnetic gradient field can be used for spatial encoding of magnetic resonance signals acquired during magnetic resonance measurements. At least one magnetic gradient coil may also include a subset of gradient coils configured to provide a magnetic gradient field within the imaging volume. In a preferred embodiment, the magnetic gradient field is oriented substantially perpendicular to the principal direction of the magnetic field lines within the imaging volume.

[0076] The surface of at least one gradient coil oriented toward the imaging volume includes a concave shape.

[0077] Preferably, at least one gradient coil is positioned between the concave surface of the at least one magnet oriented toward the imaging volume and the imaging volume. The shape of the at least one gradient coil may match the concave surface of the at least one magnet oriented toward the imaging volume.

[0078] At least one gradient coil is positioned adjacent to the surface of at least one magnet oriented toward the imaging volume.

[0079] It is conceivable that, when adopting the correct posture for performing magnetic resonance measurements, the patient sits on at least one gradient coil. However, the magnetic resonance imaging apparatus of the present invention may also include a radio frequency antenna and / or a pad positioned between at least one gradient coil and the imaging volume. Preferably, at least one gradient coil, radio frequency antenna, and / or pad includes a concave surface oriented toward the imaging volume to facilitate positioning the patient in the correct posture.

[0080] In one embodiment, the gradient field system includes a second gradient coil, wherein the surface of the second gradient coil oriented toward the imaging volume includes a concave shape, and wherein the second gradient coil is positioned adjacent to the imaging volume oriented surface of at least one magnet and / or the imaging volume oriented surface of at least one gradient coil.

[0081] The second gradient coil can be configured to generate a magnetic gradient field substantially oriented perpendicular to the principal direction of the magnetic field lines in the imaging volume. It is also conceivable that the field generation unit of the magnetic resonance imaging apparatus of the present invention includes a third gradient coil. The surface of the third gradient coil oriented toward the imaging volume may include a concave shape. Preferably, the third gradient coil is positioned adjacent to the imaging volume-oriented surface of at least one magnet and / or the imaging volume-oriented surface of the second gradient coil.

[0082] By providing a gradient coil positioned adjacent to at least one magnet and having a concave surface oriented toward the imaging volume, the spatial efficiency of field generation can be advantageously increased.

[0083] According to an alternative embodiment of the magnetic resonance imaging apparatus of the present invention, the field generation unit includes a gradient field system comprising at least one gradient coil, wherein the at least one gradient coil is recessed in a surface of at least one magnet oriented toward the imaging volume, and wherein the at least one gradient coil is configured to provide a magnetic gradient field within the imaging volume.

[0084] In one embodiment, at least one gradient coil may be recessed into the imaging volume-oriented surface of at least one magnet in such a way that the imaging volume-oriented surface of the at least one magnet is flush with the imaging volume-oriented surface of the at least one gradient coil. Preferably, the imaging volume-oriented surface of the at least one gradient coil includes a concave shape that matches the concave shape of the imaging volume-oriented surface of the at least one magnet. The at least one gradient coil may be at least partially embedded in the at least one magnet. However, it is also conceivable that, according to the embodiments of the magnetic resonance imaging system of the present invention described above, the at least one gradient coil is positioned within an aperture.

[0085] According to the above embodiments, the surface of at least one magnet oriented toward the imaging volume may correspond to the pole face of at least one magnet and / or the surface of the material of at least one magnet configured to provide a magnetic field.

[0086] When at least one gradient coil is recessed into the surface of at least one magnet oriented toward the imaging volume, the gap through which the patient enters the imaging volume can be advantageously increased.

[0087] In one embodiment of the magnetic resonance imaging device of the present invention, at least one gradient coil includes at least one recess, the at least one recess being configured to accommodate the patient's leg.

[0088] Similar to the embodiments described above, at least one gradient coil may include at least one recess for accommodating a patient's leg. It is contemplated that at least one recess of the gradient coil and at least one recess of the at least one magnet provide at least one common recess configured to accommodate one of the patient's legs. For this purpose, the position of at least one recess of the at least one gradient coil may coincide with the position of at least one recess of the at least one magnet in a manner that allows the patient to fit one leg into the at least one common recess provided via the at least one gradient coil and the at least one magnet. In a preferred embodiment, at least one gradient coil includes a second recess. The position of the second recess of the at least one gradient coil may coincide with the position of the second recess of the at least one magnet in a manner that allows the patient to fit a second leg into the second common recess provided via the at least one gradient coil and the at least one magnet. The wires or multiple wires of the at least one gradient coil may be wound in a manner that allows the wires or multiple wires to wrap around the at least one recess and / or the second recess.

[0089] When at least one gradient coil is provided, including a recess for accommodating the patient's legs, potential discomfort for the patient sitting on a surface oriented towards the imaging volume of the at least one gradient coil can be advantageously reduced or eliminated. Furthermore, by providing a recess for positioning the legs as a reference, it is advantageous to facilitate positioning the patient in the correct posture required for magnetic resonance imaging.

[0090] According to another embodiment of the magnetic resonance imaging apparatus of the present invention, the field generation unit includes a hole passing through at least one gradient coil and at least one magnet, wherein the hole is designed to provide access from the side of the at least one magnet oriented away from the imaging volume to the imaging volume.

[0091] At least one gradient coil can be positioned adjacent to or recessed into the imaging volume-oriented surface of at least one magnet. An aperture can pass through at least one gradient coil and at least one magnet in such a way that it can enter the imaging volume from the imaging volume-oriented surface of at least one magnet. The axial cross-section of the aperture can be elliptical or polygonal. The aperture passing through at least one magnet and at least one gradient coil can be configured according to the embodiment of the aperture passing through at least one magnet as described above.

[0092] With the aperture passing through at least one magnet and at least one gradient coil, a patient positioned in the correct posture can advantageously maintain eye contact with others in the examination room while facing a surface oriented toward the imaging volume of the field-generating unit. As another advantage, it significantly facilitates the entry of interventional or therapeutic instruments into the imaging volume.

[0093] In another embodiment of the magnetic resonance imaging apparatus of the present invention, at least one magnet includes a hyperboloid shape, wherein at least one magnet is configured to provide an annular imaging volume that circumferentially surrounds at least one magnet along at least a segment of the at least one magnet.

[0094] At least one magnet may comprise a hyperboloid shape. Preferably, at least one magnet is rotationally symmetric. The shape of at least one magnet may correspond to the shape of an hourglass. However, the shape of at least one magnet may also be characterized by two cones connected at their tips. In one embodiment, at least one magnet may comprise a portion or segment of a hyperboloid. The constricted or conical region of the hyperboloid may form at least one recess configured to accommodate at least one leg of a patient according to the above embodiments. It is conceivable that the imaging volume provided via at least one magnet is shaped as a toroidal body resembling at least one segment circumferentially surrounding at least one magnet. In one embodiment, the imaging volume may circumferentially surround at least one magnet along at least one segment of the rotational symmetry axis of at least one magnet. In a preferred embodiment, the position and / or shape of the toroidal imaging volume may be adapted to match the target anatomical structures, particularly the prostate or lymph nodes, of a patient sitting on the concave surface of the at least one magnet oriented toward the imaging volume. Of course, at least one magnet may be implemented according to the above embodiments.

[0095] Providing a hyperboloid shape advantageously facilitates the manufacturing process of at least one magnet. Therefore, the manufacturing cost of at least one magnet can be advantageously reduced. Furthermore, the efficiency of at least one magnet can be improved compared to a unilateral design. Due to the hyperboloid shape of at least one magnet, the imaging volume can be advantageously adapted to match the location of the prostate or lymph nodes of a patient sitting on the concave surface of at least one magnet. Attached Figure Description

[0096] Other advantages and details of the invention will become apparent from the embodiments described below and the accompanying drawings. The drawings show:

[0097] Figure 1 This is a schematic illustration of an embodiment of the magnetic resonance imaging device of the present invention.

[0098] Figure 2 This is a schematic illustration of an embodiment of the magnetic resonance imaging device of the present invention.

[0099] Figure 3 This is a schematic illustration of an embodiment of the magnetic resonance imaging device of the present invention.

[0100] Figure 4 This is a schematic illustration of an embodiment of the magnetic resonance imaging device of the present invention.

[0101] Figure 5 This is a schematic illustration of an embodiment of the magnetic resonance imaging device of the present invention.

[0102] Figure 6 This is a schematic illustration of an embodiment of the magnetic resonance imaging device of the present invention.

[0103] Figure 7 This is a schematic illustration of an embodiment of the magnetic resonance imaging device of the present invention.

[0104] Figure 8 This is a schematic illustration of an embodiment of the magnet in the magnetic resonance imaging device of the present invention.

[0105] Figure 9 This is an embodiment of the magnet in the magnetic resonance imaging device of the present invention.

[0106] Figure 10 This is a schematic illustration of an embodiment of the gradient coil of the magnetic resonance imaging device of the present invention;

[0107] Figure 11 These are schematic illustrations of an embodiment of the gradient coil in the magnetic resonance imaging apparatus of the present invention; and

[0108] Figure 12 This is a schematic illustration of an embodiment of the magnetic resonance imaging device of the present invention. Detailed Implementation

[0109] Figure 1 A schematic illustration of the magnetic resonance imaging (MRI) device 10 of the present invention is depicted, which is configured to perform magnetic resonance measurements on the mandibular region and / or eye region of a patient 15. The application of the MRI device 10 for imaging the mandibular region and / or eye region of a patient 15 should be understood as illustrative. The MRI device 10 of the present invention can also be configured to perform cardiac imaging, mammography, neurological imaging, urological imaging, orthopedic imaging, prostate imaging, or imaging of other body regions of a patient 15. The MRI device 10 of the present invention can also be configured to perform imaging on body regions of an animal.

[0110] In the depicted embodiment, the magnetic resonance imaging device 10 includes a field generation unit 12, which has a magnet 13. The magnet 13 is supported by a support structure 11 (see...). Figure 2The support structure 11 maintains the predefined shape of the magnet 13 and connects the magnet 13 to the positioning unit 29. The support structure 11 can be implemented as a yoke or backplate attached to a surface of the magnet 13 oriented away from the imaging volume 30. In one embodiment, the support structure 11 includes an adjustment mechanism (not shown) configured to modify the properties of the magnetic field (e.g., the primary magnetic field) provided via the field generation unit 12. Preferably, the adjustment mechanism includes or is mechanically connected to a magnet such as a permanent magnet, electromagnet, and / or superconducting magnet, configured to provide a secondary magnetic field. The secondary magnetic field can modify the properties of the primary magnetic field when the relative position between the field generation unit 12 and the magnet changes and / or when current is fed through the magnet. The relative position of the magnet can be adjusted manually and / or automatically via a suitable handle and / or dedicated actuator.

[0111] The cross-section of magnet 13 may include a 'U' or 'bell' shape providing access to imaging volume 30 in the X and / or Y directions (see [link]). Figure 2 The free volume between the two sides of the 'U'-shaped magnet 13 that restricts the imaging volume 30 can represent the image acquisition region 17 of the magnetic resonance imaging device 10. The image acquisition region 17 can be configured to receive a specific body region of an examination object 15, such as a patient 15 or an animal.

[0112] Patient 15 can be positioned within the image acquisition area 17 in an upright or standing posture. However, patient 15 can also be positioned within the image acquisition area 17 in a sitting or lying posture. In the latter case, a dedicated patient positioning device 34 can be used (see [link to device 15]). Figure 4 The positioning unit 29 is used to position the patient 15. However, the positioning unit 29 can also be configured to adjust the position and / or orientation of the field generating unit 12 relative to the patient 15. For example, the positioning unit 29 may include a rotary joint configured to rotate the field generating unit 12 along rotation directions WX, WZ, and / or WY. The position of the field generating unit 12 along the Y, X, and / or Z directions can be adjusted via a suitable telescope system and / or track system of the positioning unit 29. Of course, other embodiments of the support structure 11 and / or the positioning unit 29 are conceivable. In a preferred embodiment, the field generating unit 12 may be tilted via the positioning unit 29 to improve patient access and comfort.

[0113] In the example shown, magnet 13 is a main magnet configured to generate a static magnetic field in image acquisition region 17. Field generation unit 12 may also include a gradient coil 28 (see [link to example]). Figure 10 and Figure 11 The gradient field system 27 (see) Figures 4 to 6The at least one gradient coil is used to generate a magnetic gradient field for spatial encoding of the magnetic resonance signal acquired during magnetic resonance measurement. Preferably, the field generation unit 12 further includes at least one radio frequency antenna 19 (see...). Figures 4 to 6 The radio frequency system, wherein the at least one radio frequency antenna 19 is configured to transmit radio frequency excitation pulses into the image acquisition region 17. The at least one radio frequency antenna 19 may also be configured to receive magnetic resonance signals from the image acquisition region 17, particularly the imaging volume 30. In one embodiment, the at least one radio frequency antenna 19 may be configured as a local coil.

[0114] To control the field generation unit 12, the magnetic resonance imaging device 10 includes a control unit 20. The control unit 20 is configured to control the magnetic resonance imaging device 10 to perform magnetic resonance measurements on a body region of the patient 15 located within the imaging volume 30. For this purpose, the control unit 20 may include signal connections to a gradient control unit 21 and a radio frequency antenna control unit 22. It is also contemplated that the gradient control unit 21 and the radio frequency antenna control unit 22 are integrated within the control unit 20. Furthermore, the control unit 20 may include a processing unit 24 configured to coordinate the acquisition of magnetic resonance image data and / or the reconstruction of magnetic resonance image data acquired from the imaging volume 30. It is contemplated that the processing unit 24 is also configured to evaluate and / or process data, such as magnetic resonance signals and / or magnetic resonance image data. The control unit 20 may include a controller, microcontroller, analog circuitry, logic unit, etc. The processing unit 24 may include a processor, such as a CPU, GPU, etc. It is also conceivable that the control unit 20 and / or the processing unit 24 include memory and / or internal storage devices, such as RAM, ROM, PROM, EPROM, EEPROM, flash memory, and HDD, SSD, etc.

[0115] Control information (e.g., imaging parameters and / or magnetic resonance image data) may be displayed on output unit 25. Output unit 25 may include at least one monitor or screen configured to display control information and / or images acquired via magnetic resonance imaging device 10 to the operator of magnetic resonance imaging device 10. Magnetic resonance imaging device 10 may also include input unit 26 configured to receive information and / or parameters input by the operator during imaging examination. Preferably, output unit 25 and input unit 26 are part of user interface 23 configured to control and / or monitor information related to magnetic resonance measurements.

[0116] The magnetic resonance imaging (MRI) apparatus 10 shown may, of course, include other components typically included in an MRI apparatus 10. The general operating mode of the MRI apparatus 10 is well known to those skilled in the art. Therefore, further description of the general components or the sequence of MRI measurements is considered unnecessary.

[0117] A preferred embodiment of the magnetic resonance imaging device 10 is configured to perform:

[0118] • Neurological imaging of the spine of patient 15, thereby enhancing treatment and / or stimulation during the scan; Magnetic resonance imaging device 10 can be used in conjunction with other sensors such as EEG, thereby avoiding contraindications associated with deep brain stimulators, etc.

[0119] • Imaging of the prostate of patient 15, wherein the access to the imaging volume 30 is oriented in a manner that allows patient 15 to sit or lie on the magnetic resonance imaging device 10 and provides enhanced access to the prostate region, for example, with the opening 32 oriented upward (e.g., see...). Figure 2 , Figure 6 , Figure 7 ); Lymph node imaging can also be accomplished by repositioning the patient 15.

[0120] • Visualize body regions of animals, such as the limbs of large animals like horses or cattle; imaging volume 30 with opening 32 (see...). Figures 4 to 6 It can be oriented upwards to facilitate the placement of animals (such as cats, dogs, hamsters, etc.) on suitable positioning aids and mats.

[0121] Due to its enhanced openness, the magnetic resonance imaging apparatus 10 of the present invention can be easily combined with other imaging modalities such as platform or C-arm X-ray scanners, ultrasound scanners, and optical imaging devices. Other imaging modalities can even be used to improve the results of magnetic resonance measurements by providing high-resolution navigator signals and facilitate data fusion.

[0122] Figure 2An embodiment of the magnetic resonance imaging device 10 of the present invention is depicted, wherein a plurality of positioning aids 14a, 14b, 14c, and 14d (14a to 14d) support a patient 15 in the correct posture for magnetic resonance measurement of the prostate. Two positioning aids 14a and 14b are configured to support the patient 15’s arms and feet at predetermined positions during the magnetic resonance measurement. In the example shown, the position and / or orientation of the positioning aids 14a and 14b can be automatically adapted via a control unit 20. For this purpose, a processing unit 24 can receive height, weight, sex, age, and / or other patient information from a source (e.g., a hospital information system) and output control information to the control unit 20 based on the patient information. The control unit 20 can output control signals to a driver of an adjustment unit (not shown), which changes the position and / or orientation of the positioning aids 14 according to the control information. In contrast, positioning aids 14c and 14d can be pads that passively support the patient 15 to maintain the correct posture. Preferably, the positioning aids 14c and 14d comprise rigid foam to prevent the patient from moving during magnetic resonance imaging (MRI) measurements.

[0123] In the example shown, the field generation unit 12 includes a magnet 13 and a first gradient coil 28a and a second gradient coil 28b. The first gradient coil 28a and the second gradient coil 28b are positioned adjacent to the surface of the magnet 13 oriented toward the imaging volume 30. Figure 2 In the illustrated embodiment, the correct posture requires the patient 15 to sit on the surface of the gradient coil 28a oriented toward the imaging volume 30 in such a manner that the prostate and / or nearby lymph nodes are covered by the imaging volume 30. To increase patient comfort, the shapes of the surfaces of the magnet 13, gradient coil 28, and gradient coil 28b oriented toward the imaging volume 30 are preferably concave (“U-shaped”) in the anterior-posterior direction of the patient 15 and convex in the lateral direction of the patient 15. It is conceivable that the magnet 13 is tilted relative to the substantially horizontal floor of the examination room to support the patient 15 when entering the imaging volume 30 and / or maintaining the correct position.

[0124] Figure 3 It shows Figure 2 The diagram shows a top view of an alternative embodiment of the magnetic resonance imaging device 10 of the present invention. The magnet 13 includes two recesses 33a and 33b configured to accommodate the legs of a patient 15. The recesses 33a and 33b are offset relative to the imaging volume 30 along the Z-direction. Therefore, the legs protruding forward from the patient 15 can be comfortably positioned within the recesses 33a and 33b. Of course, the shape of the recesses 33a and 33b and / or their relative positions to the magnet 13 can be varied to consider specific groups of patients (e.g., children, women, men, the elderly) and / or different patient body shapes.

[0125] Figure 4 An embodiment of the magnetic resonance imaging apparatus 10 of the present invention is depicted, wherein a patient 15 is positioned to one side in a lateral decubitus position. Positioning the patient 15 in a lateral decubitus position has the advantage of providing a particularly comfortable and stable position for the patient 15 during magnetic resonance measurements. The patient 15 can be placed on a patient positioning device 34, which can be configured to adjust the relative position between the patient 15 and the field generation unit 12, at least along a horizontal line substantially parallel to the sagittal orientation of the patient 15. Therefore, the magnetic resonance imaging apparatus 10 of the present invention can be used to examine multiple target anatomical structures, such as the prostate, spine, and / or brain of the patient 15.

[0126] It is also conceivable that multiple target anatomical structures and / or multiple segments of a target anatomical structure can be examined in multiple steps, for example, by continuously or discontinuously changing the relative position between the patient 15 and the field generation unit 12 during magnetic resonance measurement. In a preferred embodiment, the patient 15 can be moved relative to the field generation unit 12 to continuously cover the target anatomical structure. Figure 4 As shown, the continuity of coverage can be achieved along the target anatomical structure in a cranial or caudal direction. However, the continuity of coverage can also be achieved in the anterior-posterior and lateral directions. It is also conceivable that the continuity of coverage may include, for example... Figure 1 The field generation unit 12 shown is tilted relative to the patient 15 along the WX, WY, and / or WZ directions. In one embodiment, the magnetic resonance imaging device 10 can be configured to perform multi-plate imaging, or more generally, multi-position imaging. Multi-plate or multi-position imaging may include performing magnetic resonance measurements on a volume or target anatomical structure larger than the imaging volume 30. For this purpose, the relative position between the field generation unit 12 and the imaging object can change continuously or discontinuously during the magnetic resonance measurement.

[0127] In the depicted embodiment, the field generation unit 12 includes a gradient field system 27, which includes one or more gradient coils 28 and a radio frequency antenna 19. The surface of the radio frequency antenna 19 oriented toward the imaging volume 30 may include a concave shape that matches the concave shape of the surface of the gradient field system 27 and / or the magnet 13 oriented toward the imaging volume 30.

[0128] Figure 5 An embodiment of the magnetic resonance imaging apparatus 10 of the present invention is shown, wherein the field generation unit 12 is relative to... Figure 4 The illustrated embodiment is tilted or rotated. It is conceivable that the positioning unit 29 (not shown) is configured to tilt or rotate the field generation unit 12 to facilitate the patient 15's entry into the imaging volume during magnetic resonance imaging and / or to increase the patient 15's comfort. Figure 5As shown, patient 15 can be placed on positioning aid 14 within the image acquisition area 17. However, it is also conceivable that patient 15 is placed on the surface of field generation unit 12 or on patient positioning device 34 positioned within image acquisition area 17 (see [reference]). Figure 4 )superior.

[0129] Figure 6 Another embodiment of the magnetic resonance imaging apparatus 10 of the present invention is shown. In this example, the opening of the magnet 13 is oriented upward (e.g., along the Y direction) so that the patient 15 can enter the imaging volume 30 along the Y and / or X directions. During the magnetic resonance measurement, the patient 15 can remain in a supine position. The patient 15 can enter the imaging volume 30 via, as shown in... Figure 2 and Figure 5 The positioning aid 14 shown is supported. The depicted posture of the patient 15 corresponds to the correct posture for performing magnetic resonance measurements of the patient 15's spine. The field generation unit 12 advantageously provides increased accessibility for the use of interventional and / or therapeutic instruments while performing magnetic resonance measurements. The increased accessibility of the field generation unit 12 also facilitates access to the imaging volume 30 and / or provides a stable and / or comfortable position that the patient 15 can easily maintain during magnetic resonance measurements. However, the magnet 13 can still surround the imaging volume 30 and / or the patient 15 in a manner that allows sufficient coverage of the imaging volume 30 and / or the patient 15 to be provided using magnetic materials and generates a suitable B0 magnetic field for performing magnetic resonance measurements.

[0130] Figure 7 An embodiment of the magnetic resonance imaging apparatus 10 of the present invention is shown, wherein the magnet 13 comprises a plurality of smaller permanent magnets 13i. In the depicted example, the permanent magnets 13i are bar magnets radially oriented relative to the center 31 of the imaging volume. The permanent magnets 13i are arranged to provide a concave surface oriented toward the imaging volume 30.

[0131] To generate a uniform main magnetic field within the imaging volume, it may be beneficial to increase the density of magnetic material (e.g., the number and / or density of permanent magnets, resistance coils, or superconducting materials) in the sides of the "U"-shaped magnet 13 compared to a concave area directly positioned below the imaging volume 30 along the Y direction. It is also conceivable that a reduction in magnetic material in the region below the imaging volume 30 (e.g., along the Y direction) will not excessively impair or constrain the provision of a uniform main magnetic field within the imaging volume 30. Therefore, the concept of increasing the density of magnetic material in the outer side of the concave or "U"-shaped magnet 13 can also represent a design standard for the gradient coil 28 and the radio frequency antenna 19 positioned adjacent to the magnet 13. Furthermore, when the design is configured to accommodate a concave or "U"-shaped magnet 13, the density of magnetic material in the sides of the "U"-shaped magnet 13 can also represent a design standard for the gradient coil 28 and the radio frequency antenna 19 positioned adjacent to the magnet 13. Figure 2When a patient 15 in a seated position is placed in the magnetic resonance imaging device 10 of the present invention, reducing the density of the magnetic material in the recess below the imaging volume 30 can advantageously facilitate the implementation of the recess 33 in the magnet 13, gradient coil 28, and / or radio frequency antenna 19 (see [link]). Figure 3 ).

[0132] As another advantage, the region with lower density magnetic material is well-suited for realizing the aperture 35 through the field generation unit 12. The aperture 35 can be used to introduce medical devices such as needles, catheters, and / or local coils from the back side of the magnet 13 into the imaging volume 30.

[0133] In one embodiment, the permanent magnets 13i of the magnet 13 are arranged to surround the recesses 33a and 33b for accommodating the leg of the patient 15. Furthermore, the surface area of ​​the concave surface oriented toward the imaging volume 30 may differ from, and in particular, be smaller than, the surface area of ​​the surface oriented away from the imaging volume 30. The cross-section of the permanent magnet 13i may gradually decrease in the direction from a point on the surface oriented away from the imaging volume 30 toward the center 31 of the imaging volume. It is also conceivable that the spacing between the individual permanent magnets 13i decreases in the same direction. Therefore, the density of the magnetic material may increase in the direction toward the imaging volume 30 and decrease in the direction toward the recess of the concave magnet 13.

[0134] Figure 8 An embodiment of a superconducting magnet 13, in which the magnet 13 is a coil comprising a superconducting wire 13i, is shown. The superconducting wire 13i may include a low-temperature superconductor or a high-temperature superconductor connected to a cryostat (not shown) to maintain the temperature of the superconducting magnet 13 below a predetermined value. The superconducting wire 13i is substantially arranged in a curved surface that provides a concave surface oriented toward the imaging volume 30. Furthermore, the superconducting wire 13i is arranged to surround two recesses 33a and 33b configured to accommodate the leg of a patient 15. The superconducting magnet 13 may also include an aperture 35, which may be located in a region of the recess in the concave surface of the magnet 13 (where the density of the superconducting wire 13i may be low). Thus, a medical device can be introduced into the imaging volume 30 from the surface of the magnet 13 that is oriented away from the imaging volume 30.

[0135] Figure 9 Alternative embodiments of the magnet 13 providing an imaging volume 30 with a complex three-dimensional shape are depicted. The shape of the imaging volume 30 is particularly suitable for performing magnetic resonance measurements of the jaw region and / or teeth of the patient 15 when the magnetic field lines follow the shape of the dental arch as they move in the Y direction from the center 31 of the imaging volume. However, the magnetic resonance imaging device 10 of the present invention may also include imaging volumes 30 of different shapes, such as elliptical, oval, or spherical imaging volumes.

[0136] The principal direction of the magnetic field lines (particularly those via the static magnetic field (BO field) provided by magnet 13) within the imaging volume 30 can be oriented along the Z direction. The patient 15 can choose to enter the imaging volume 30 along one of two perpendicular spatial directions, such as the X and Y directions. However, entry into the imaging volume 30 is not limited by these two spatial directions. The magnetic resonance imaging apparatus 10 according to the above embodiment also allows the patient 15 to enter the imaging volume 30 along three perpendicular spatial directions.

[0137] Figure 10 An embodiment of a gradient coil 28 positioned adjacent to a surface of magnet 13 oriented toward imaging volume 30 is depicted. As shown, the gradient coil 28 may include multiple coils or wires arranged in a curved surface. The depicted gradient coil 28 may be a first gradient coil (e.g., a Z-axis gradient coil) configured to provide a magnetic gradient field oriented along the Z-direction. Furthermore, the first gradient coil 28 may include two recesses 33a and 33b configured to accommodate... Figure 2 The correct posture shown is for positioning the legs of patient 15.

[0138] Figure 11 An embodiment of an alternative gradient coil 28 positioned adjacent to the surface of magnet 13 oriented toward imaging volume 30 and / or the surface of the first gradient coil 28 is depicted. Similar to... Figure 10 In the illustrated embodiment, the alternative gradient coil 28 may include a plurality of coils or wires arranged in a curved surface. The alternative gradient coil 28 may be a second gradient coil (e.g., an X-axis gradient coil) configured to provide a magnetic gradient field along the Y direction. The plurality of coils or wires of the second gradient coil 28 may be arranged such that they surround two recesses 33a and 33b configured to accommodate the leg of the patient 15.

[0139] about Figure 10 and Figure 11 The Z-axis and X-axis can be positioned such that the Z-axis gradient coil 28 and the X-axis gradient coil 28 are arranged symmetrically with respect to a plane oriented parallel to the X-axis and Y-axis. Instead of arranging the Z-axis gradient coil 28 and the X-axis gradient coil 28 such that one horizontal axis is oriented along the concave surface of the magnet 13 (e.g., along a U-shaped profile) and the other horizontal axis is oriented radially to the concave portion of the concave surface, rotating the coordinate system by 45° about the Z-direction allows for a more balanced gradient coil arrangement.

[0140] The magnetic resonance imaging apparatus 10 of the present invention may further include a third gradient coil (not shown) configured to provide a magnetic gradient field oriented along the Y direction (e.g., a Y-axis gradient coil). In one embodiment, the winding pattern of the third gradient coil may be similar to the winding pattern of the second gradient coil 28. However, compared with... Figure 11 Compared to the winding pattern of the second gradient coil 28 shown, the winding pattern of the third gradient coil can be reversed or reflected.

[0141] Further reference Figure 2 The order or sequence of the first gradient coil 28, the second gradient coil 28, and / or the third gradient coil relative to the distance to the imaging volume 30 (or to the distance to the surface of the magnet 13 oriented toward the imaging volume 30) can be arbitrary. For example, the first gradient coil 28 can be positioned on the surface of the magnet 13 oriented toward the imaging volume 30, while the second gradient coil 28 is positioned on the surface of the first gradient coil 28 oriented toward the imaging volume 30. It is also conceivable that the second gradient coil 28 is positioned on the surface of the magnet 13 oriented toward the imaging volume 30, while the first gradient coil 28 is positioned on the surface of the second gradient coil 28 oriented toward the imaging volume 30. The third gradient coil 28 can be positioned adjacent to the magnet 13, the first gradient coil 28, and / or the second gradient coil 28. Figure 6 The magnetic resonance imaging device 10 of the present invention may further include a radio frequency antenna 19. Preferably, the radio frequency antenna 19 is positioned (compared to the magnet 13 and / or gradient coil 28) closest to the patient 15 to enhance the signal-to-noise ratio of the magnetic resonance signal acquired from the imaging volume 30.

[0142] according to Figures 7 to 11 A region with reduced conductor or magnetic material density can be located in a recess below the imaging volume 30. This region can be advantageously used to provide an aperture 35 through the field generation unit 12 (e.g., each layer of magnet 13 and gradient coil 28 and / or radio frequency antenna 19). The aperture 35 can provide space for interventional devices and / or an additional diffusion gradient system (not shown) to generate a strong field for the diffusion pulse.

[0143] Figure 12 An embodiment in which the magnet 13 comprises a rotationally symmetric hyperboloid shape is shown. For example... Figure 12 As depicted, the constricted or conical region of the magnet 13 may form at least one recess 33 configured to accommodate the leg of the patient 15. The imaging volume 30 may circumferentially surround the magnet 13 along at least a portion of its rotational symmetry axis. In particular, the imaging volume 30 may include an annular shape.

[0144] The above embodiments should be considered as examples. Individual embodiments can be extended by features of other embodiments.

Claims

1. A magnetic resonance imaging apparatus (10), the magnetic resonance imaging apparatus (10) comprising a field generation unit (12), the field generation unit (12) being configured to provide a magnetic field in an imaging volume (30) of the magnetic resonance imaging apparatus (10), wherein, The field generating unit (12) includes at least one magnet (13). The surface of the at least one magnet (13) oriented toward the imaging volume (30) includes a concave shape, wherein the entry direction (16) to the imaging volume (30) is oriented substantially perpendicular to the main direction of the magnetic field lines in the imaging volume (30), and The at least one magnet (13) is designed to accommodate a patient (15) in a seated position on a surface oriented toward the imaging volume (30), and the at least one magnet (13) includes at least one recess (33) configured to accommodate the legs of the patient (15) in a seated position.

2. The magnetic resonance imaging apparatus (10) according to claim 1 further includes a positioning aid (14) configured to support the patient (15) in the correct posture for performing magnetic resonance imaging measurements, wherein, The correct posture is characterized by a predefined relative position between the patient (15) and the magnetic resonance imaging device (10), and wherein, when the patient (15) is positioned in the correct posture, at least a portion of the target anatomical structure of the patient (15) is covered by the imaging volume (30).

3. The magnetic resonance imaging device (10) according to claim 2, wherein, The positioning aid (14) includes an adjustment unit and a processing unit (24), wherein the adjustment unit is configured to adjust the position and / or orientation of the positioning aid (14) relative to the at least one magnet (13), and wherein the processing unit (24) is configured to receive patient information and control the adjustment unit to adapt the position and / or orientation of the positioning aid (14) according to the patient information.

4. The magnetic resonance imaging apparatus (10) according to any one of claims 1 to 3, wherein, The at least one magnet (13) is designed to provide access to the imaging volume (30) along at least two vertical spatial directions, and wherein each of the two vertical spatial directions is oriented substantially perpendicular to the main direction of the magnetic field lines in the imaging volume (30).

5. The magnetic resonance imaging apparatus (10) according to any one of claims 1 to 3, wherein, The surface of the at least one magnet (13) oriented toward the imaging volume (30) is shaped to match at least a portion of the contour of a body region of the patient (15), wherein the body region of the patient (15) includes at least one of the following: o Spine region o Facial area, pelvic region o breast area, o Abdominal region, limbs.

6. The magnetic resonance imaging device (10) according to claim 5, wherein, The surface of the at least one magnet (13) oriented toward the imaging volume (30) is shaped to match the contour of the pelvic region of the patient (15) and is designed to accommodate the patient (15) in a seated position, wherein, when the patient (15) is positioned in a seated position, at least a portion of the patient's (15) prostate and / or lymph nodes adjacent to the prostate are located within the imaging volume (30).

7. The magnetic resonance imaging apparatus (10) according to any one of claims 1 to 3, wherein, The field generation unit (12) includes an adjustment mechanism configured to adjust the position and / or orientation of at least a portion of the field generation unit (12) and modify the properties of the magnetic field provided by the field generation unit (12), wherein the properties of the magnetic field include at least one of the following: the shape of the imaging volume (30), the position of the imaging volume (30), the magnetic field strength and / or the direction of the magnetic field lines.

8. The magnetic resonance imaging apparatus (10) according to any one of claims 1 to 3, wherein, The at least one magnet (13) includes at least one of the following: o permanent magnet, Array of permanent magnets o Resistor coil, an array of resistance coils, o High-temperature superconductor, o Low temperature superconductor, and The surface of the at least one magnet (13) oriented toward the imaging volume (30) corresponds to the pole face of the at least one magnet (13) and / or the surface of the material of the at least one magnet (13) configured to provide a magnetic field.

9. The magnetic resonance imaging apparatus (10) according to any one of claims 1 to 3, wherein, The surface of the at least one magnet (13) oriented toward the imaging volume (30) includes a hole (35), wherein the hole (35) is configured to provide access to the imaging volume (30) from the side of the at least one magnet (13) oriented away from the imaging volume (30).

10. The magnetic resonance imaging apparatus (10) according to any one of claims 1 to 3, wherein, The field generation unit (12) includes a gradient field system (27) including at least one gradient coil (28) configured to provide a magnetic gradient field within the imaging volume (30), wherein the surface of the at least one gradient coil (28) oriented toward the imaging volume (30) includes a concave shape, and wherein the at least one gradient coil (28) is positioned adjacent to the surface of the at least one magnet (13) oriented toward the imaging volume (30).

11. The magnetic resonance imaging apparatus (10) according to any one of claims 1 to 3, wherein, The field generation unit (12) includes a gradient field system (27) including at least one gradient coil (28), wherein the at least one gradient coil (28) is recessed into a surface of the at least one magnet (13) oriented toward the imaging volume (30), and wherein the at least one gradient coil (28) is configured to provide a magnetic gradient field within the imaging volume (30), wherein the surface of the at least one magnet (13) oriented toward the imaging volume (30) corresponds to the pole face of the at least one magnet (13) and / or the surface of the at least one magnet (13) of a material configured to provide a magnetic field.

12. The magnetic resonance imaging device (10) according to claim 10, wherein, The at least one gradient coil (28) includes at least one recess (33) configured to accommodate the leg of the patient (15).

13. The magnetic resonance imaging device (10) according to claim 10, wherein, The field generation unit (12) includes an aperture (35) that passes through the at least one gradient coil (28) and the at least one magnet (13), wherein the aperture (35) is designed to provide access from the side of the at least one magnet (13) away from the imaging volume (30) to the imaging volume (30).

14. The magnetic resonance imaging apparatus (10) according to any one of claims 1 to 3, wherein, The at least one magnet (13) includes a hyperboloid shape, and wherein the at least one magnet (13) is configured to provide an annular imaging volume that circumferentially surrounds the at least one magnet (13) along at least a segment of the at least one magnet (13).

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