Apparatus, system and method for performing magnetic resonance measurements of a full dentition

Abstract

The invention relates to an antenna array for receiving radio frequency signals in the frequency range and power range of a magnetic resonance device, comprising at least one signal conductor and a carrier element connected with the antenna array. The carrier element contours at least a part of the full dentition of an examination object and can be connected in a position-dependent form-fitting manner with the full dentition of a patient. The invention also relates to a system comprising a magnetic resonance device and an antenna array, wherein the magnetic resonance device has a signal connection with the antenna array and is configured to receive radio frequency signals of the antenna array and to create image data of the full dentition of an examination object. The invention also relates to a method for performing a magnetic resonance measurement of the full dentition of an examination object using an antenna array, the method having the steps of orienting the carrier element with the antenna array relative to the full dentition of an examination object, connecting the carrier element with the full dentition of an examination object, and performing a magnetic resonance measurement of the full dentition of an examination object.

Description

TECHNICAL FIELD

[0001] The invention relates to an antenna array for receiving radio frequency signals in the frequency range and power range of a magnetic resonance device, comprising at least one signal conductor and a carrier element, which is connected with the antenna array, wherein the carrier element contours at least a part of the full dentition of an examination object and can be connected in a position-dependent form-fitting manner with the full dentition of the examination object. The invention further relates to a system comprising a magnetic resonance device and an antenna array, wherein the magnetic resonance device has a signal connection to the antenna array, and a method for performing a magnetic resonance measurement on the full dentition of an examination object with the antenna array, wherein the antenna array is connected in a predetermined relative position with the full dentition of the examination object. BACKGROUND

[0002] Diagnosis and treatment of the jaw region and the tooth region are currently mainly based on X-ray imaging methods, which potentially expose the patient to ionizing radiation. By using magnetic resonance-based imaging methods, this radiation burden of the patient can be avoided. However, this approach is so far associated with technical challenges that make widespread application difficult.

[0003] On the one hand, the region to be shown, for example teeth, tooth roots or tooth defects, has a relatively small volume available for signal generation. On the other hand, the patient's mouth, including the tongue region, the jaw region and the cheek region, is a region of large human motion, which can lead to image artifacts, for example diffuse image noise or ghosting, in the usual measurement duration of a magnetic resonance measurement. Here, the patient's involuntary tongue movements and swallowing movements are the main problem, since they cannot always be arbitrarily stopped for a longer period of time. For this reason, the measurement duration of a magnetic resonance measurement of the mouth should be kept as short as possible.

[0004] In order to compensate for the low signal volume, the receiving antenna must be guided very close to the patient's anatomical region to be examined. Conventional volume coils and surface coils, for example head coils and paving coils, are placed externally at the patient and have a relatively large spacing from the patient's mouth. The achievable spacing is often too high to obtain high-quality images. In addition, patient movements within the mouth cannot be limited by an external antenna system. In a measurement duration of a few minutes, it can be expected that anatomical structures in the imaging region move, for example due to swallowing movements or tensioning of the jaw muscles.

[0005] In order to provide an economically interesting alternative to X-ray-based imaging methods, magnetic resonance devices with low field strength are also required, which generally have a lower signal-to-noise ratio, making operation with external antenna systems difficult.

[0006] A potential solution is an intraoral antenna system which can be introduced into the mouth of a patient and locally positioned at the anatomical structure to be examined. Thereby a lower signal-to-noise ratio of a magnetic resonance device with a low field strength can be partially compensated. However, positioning an antenna system in the mouth of a patient can cause adverse reactions of the patient, such as gagging, increased salivation and involuntary sweeping with the tongue. Without further measures, the reactions lead to image artifacts, in particular due to the tongue being in close proximity to the imaging signal conductors of the antenna system. Furthermore, the mouth with the dental arch and the tongue provides a complex spatial geometry which is also exhibited by soft tissue like tongue muscles and cheeks. This makes a stable positioning of the signal conductors mainly in regions with a high soft tissue fraction difficult. Furthermore, the geometry of the jaw bones and the full set of teeth can vary greatly from patient to patient, so that the development of a prototype in this field is associated with an individual adaptation of the antenna to the full set of teeth of the examinee. In medical applications, this would mean a high cost and a high effort which hinders the widespread use of magnetic resonance methods as imaging of the jaw region and the dental region. SUMMARY

[0007] It is therefore the object underlying the present invention to provide a method and a device which improve the image quality of a magnetic resonance examination of the dental region and the jaw region and which are applicable to a large number of patients.

[0008] The object is achieved by the antenna array according to the invention, the system according to the invention and the method according to the invention as described in accordance with the embodiments of the invention.

[0009] The antenna array according to the invention for receiving radio frequency signals in the frequency range and power range of a magnetic resonance device comprises a signal conductor which constitutes a radio frequency signal for receiving an alternating magnetic field and which transmits the radio frequency signal to a magnetic resonance device, and a carrier element which is connected to the signal conductor.

[0010] The antenna array for receiving radio frequency signals can be a coupling element between a guided electromagnetic wave or alternating magnetic field in a conductor and an unguided, i.e. in free space. The antenna array preferably constitutes a radio frequency signal for receiving electromagnetic waves in the range of the magnetic resonance frequencies of different magnetic resonance active atomic nuclei. For example, electromagnetic waves with frequencies between 1 MHz and 500 MHz, preferably between 10 MHz and 300 MHz, are considered as radio frequency signals. The magnetic resonance signals of the common atomic nuclei to be examined can have a low power of several micro- to several milliwatts.

[0011] The signal conductor is preferably an electrically conductive wire in which an electric current is induced by an alternating magnetic field. The wire of the signal conductor can have any elliptical or polygonal cross section suitable for the permanent transmission of the above-mentioned power. It is likewise conceivable for the signal conductor to be embodied as a printed conductor on a circuit board and to have an approximately rectangular cross section. The signal conductor is preferably composed of copper. However, other electrically conductive metals, such as gold or aluminum, and combinations thereof, such as a silver-plated or gold-plated signal conductor composed of copper, are also conceivable. The signal conductor and / or the antenna array preferably has a contact protection which protects the examination object from voltage and / or burns. To this end, the antenna array and / or the signal conductor can, for example, have a cover and / or a shield made of plastic. Suitable plastics are, for example, polytetrafluoroethylene (PTFE) or various silicones.

[0012] In order to transmit the received magnetic resonance signals to the magnetic resonance device, the signal conductor is preferably electrically connected to the magnetic resonance device. It is conceivable for the connection between the antenna array and the magnetic resonance device to take place via an electrical connection line which electrically connects the antenna array to the magnetic resonance device. Such an electrical connection line can be, for example, a coaxial cable which has a shield in order to avoid electromagnetic interference from the environment. The electrical connection line is preferably connected to a corresponding physical interface of the receiver. However, it is also conceivable for the antenna array to be connected wirelessly to the magnetic resonance device. To this end, the antenna array can have a transmitter which transmits the measured magnetic resonance signals to the magnetic resonance device by means of the emission of electromagnetic or acoustic waves. The magnetic resonance device can have a corresponding receiver which is suitable for receiving the signals of the transmitter of the antenna array.

[0013] It is also conceivable for the antenna array to have an electronic circuit which is connected to the signal conductor. The electronic circuit can comprise a combination of one or more electronic components, such as transistors, resistors, capacitors, diodes, printed conductors, etc. The electronic circuit can, inter alia, have a protection circuit which is suitable for protecting the antenna array from overloads. In order to avoid magnetic attractive forces, standing waves, heating and similar undesirable effects, the electronic circuit can have a high proportion of non-magnetic materials and corresponding sheath current barriers and / or Baluns. The electronic circuit preferably has a printed circuit board (PCB) or a similar carrier structure which is suitable for accommodating the electronic components in predetermined positions relative to one another.

[0014] The carrier element preferably provides a holder for the signal conductor and / or the antenna array and is mechanically connected thereto. The mechanical connection can be made by means of any form fit, force fit and / or material fit connection. It is conceivable, for example, that the antenna array is glued or screwed to the carrier element. However, it is also possible that the signal conductor and / or the antenna array is hung, clamped, inserted into or welded to the carrier element. By means of the connection to the carrier element, the structural stability of the signal conductor and / or the antenna array can be improved. The carrier element is preferably made of a shape-stable electrically insulating material for this purpose. It is also conceivable that the material of the carrier element is non-magnetic or has a low interaction with magnetic fields. Since the carrier element can be connected in a form fit to the full dentition of the examination object in the position according to the application, the material of the carrier element preferably also has a high biocompatibility. A material having a high biocompatibility is characterized, inter alia, by a high cell and blood compatibility and is preferably histopathologically harmless. Possible materials are, for example, plastics, such as silicone, polyether, polyamide, polycarbonate, but also polymers of various natural substances, such as proteins, sugars, peptides, etc. Furthermore, ceramics are also conceivable, such as aluminum oxide, gypsum, hydroxyapatite, etc. For example, a mammal, preferably a primate, particularly preferably a human being, is considered to be the examination object.

[0015] The carrier element of the antenna array is shaped to at least a part of the full dentition of the examination object, wherein the carrier element can be connected in a form fit to the full dentition of the examination object in the position according to the application in order to position the signal conductor of the antenna array on the full dentition of the examination object.

[0016] When the carrier element is connected to the full dentition of the examination object in a form-fitting manner, there is preferably a position of the carrier element according to the application. It is conceivable that the spacing between the full dentition and the carrier element is smallest in the position of the carrier element according to the application, so that the signal conductors of the antenna array are positioned as close as possible to the full dentition of the examination object. The connection between the carrier element and the full dentition is here form-fitting. This can mean that the shape of the carrier element and the shape of the full dentition match each other or engage with each other, so that the movement play of the carrier element in the position according to the application is limited at least in one spatial direction by the full dentition. It is likewise conceivable that at least one degree of freedom of movement, for example a rotational movement or a translational movement, is limited by the full dentition. The full dentition can here comprise a part of the teeth, the interdental space, one tooth, a plurality of teeth, one dental arch or a plurality of dental arches. The full dentition can also be edentulous, i.e. represent a part of a dental arch or an entire dental arch without teeth. The dental arch usually has the periodontal tissue (Zahnhalteapparat) or a part of the periodontal tissue with the full teeth or a part of the teeth of the upper jaw or the lower jaw. The full dentition and the carrier element preferably touch at least at one point in the position according to the application. However, it is desirable that the carrier element and the full dentition touch at a plurality of points in the position of the carrier element according to the application in order to limit the movement play of the carrier element. The outer configuration of the carrier element is preferably shaped in such a way that the carrier element can be introduced into the open mouth of the examination object, in particular a person.

[0017] By using a carrier element which copies the full dentition of the examination object, the positioning of the antenna array according to the application can be simplified in an advantageous manner. Furthermore, the signal-to-noise ratio and the image quality of the magnetic resonance examination can be improved in an advantageous manner by positioning the antenna array in the oral cavity near the anatomical structures relevant for imaging.

[0018] Further advantageous embodiments are explained in the following.

[0019] In one embodiment of the antenna array according to the application, the antenna array constitutes a means for emitting radio frequency signals in the frequency range and power range of a magnetic resonance device into an examination object. The antenna array can for this purpose have one or a plurality of dedicated signal conductors for transmitting the radio frequency signals. However, it is likewise conceivable that one or a plurality of signal conductors are used alternately for transmitting and for receiving the radio frequency signals. In order to excite nuclear spins in the examination object, the transmission power of the antenna array can usually be in the power range of several watts to several kilowatts depending on the static magnetic field of the magnetic resonance device. The cross section of the signal conductors of the antenna array, the contact protection and / or the electronic circuit are preferably coordinated with the transmission power of the antenna array and can permanently provide said transmission power.

[0020] It is conceivable that the antenna array generates an alternating magnetic field B1 which briefly deflects the orientation of the atomic nuclei in the examination object from the orientation with the static magnetic field B0. It is likewise conceivable that the antenna array receives magnetic resonance signals of the atomic nuclei deflected by the alternating magnetic field B1 and transmits them to the magnetic resonance device. The signal conductors for transmitting the radio frequency signals can be arranged on the carrier element and positioned at the application-dependent locations on the full dentition of the examination object. It is however also conceivable that the signal conductors for transmitting the radio frequency signals are arranged outside the mouth and have a signal connection to the antenna array. The external arrangement of the corresponding signal conductors can at least partially enclose the head of the examination object. The external arrangement preferably has a cage (English: birdcage) or drum structure which generates a circularly polarized or linearly polarized magnetic field inside.

[0021] By using the antenna array for transmitting and receiving the radio frequency signals, the alternating magnetic field can be generated and detected locally and specifically. Thereby, a low signal volume in the mouth of the examination object can be displayed with a higher sensitivity in an advantageous manner.

[0022] According to one embodiment of the antenna array according to the application, the signal conductors of the antenna array are embedded in the material of the carrier element. The signal conductors are here preferably embedded along the surface of the carrier element such that the spacing from the surface of the full dentition is as small as possible at the application-dependent locations of the carrier element on the full dentition. The signal conductors can completely enter the material of the carrier element or can partially protrude from the surface of the carrier element. The signal conductors are here preferably surrounded by the material of the carrier element. It is conceivable that the material of the carrier element establishes a contact protection of the signal conductors for the examination object.

[0023] It is also conceivable that at least a part of the electronic circuit of the antenna array is embedded in the carrier element.

[0024] By embedding the signal conductors in the material of the carrier element, a contact protection of the antenna array can be provided by the carrier element in an advantageous manner. Furthermore, the signal conductors and / or the circuit of the antenna array in the carrier element can be protected from the aggressive effects of the commonly used disinfection and cleaning methods, such that the antenna array can be cleaned and reused in an advantageous manner.

[0025] In a further embodiment of the antenna array, the signal conductor of the antenna array has a loop which contours at least a portion of the dental arch of the examination object. The loop is for example a section of the signal conductor which is approximately ring-shaped. However, the loop can also have a further shape. For example, an elliptical shape, a polygonal shape and any geometric deformation of the mentioned shapes are conceivable. It is also conceivable that the loop has the shape of a figure eight, or can be obtained from the mentioned shapes by twisting, folding and / or twisting. Here, at least a portion of the loop contours a portion of the dental arch of the examination object. This can mean that the loop at least on one section of the dental arch follows a trajectory which follows the dental arch. The loop preferably follows the trajectory of the dental arch at least along half of the dental arch. However, it is also conceivable that the loop follows the entire dental arch and ends with the end of the dental arch. For example, the end of the dental arch can be the tooth which is located at the end in the direction of the pharynx of the examination object. However, the end of the dental arch can also be the incisor, which is the first tooth of the dental arch in the direction of the open mouth of the examination object. It is also conceivable that the signal conductor of the loop leads over one or more sections of the dental arch.

[0026] The loop-shaped signal conductor can generally be manufactured cost-advantageously. Due to the simple design, the loop can be adapted to the carrier element and / or integrated into the carrier element in an advantageous manner. Thereby, the manufacturing effort of the antenna array can be reduced.

[0027] In a further embodiment of the antenna array according to the application, the antenna array has a signal conductor array, wherein the signal conductor array contours at least a portion of the dental arch. The signal conductor array preferably comprises a plurality of signal conductors which are connected to the magnetic resonance device and / or to the electronic circuitry. It is especially conceivable that each signal conductor of the plurality of signal conductors is electrically connected to a reception channel of the magnetic resonance device. Furthermore, signal conductors of the plurality of signal conductors can also be connected to each other.

[0028] The signal conductors can have a loop according to one of the above-mentioned shapes. The loops of the signal conductors preferably have an elliptical shape. The loops can for example be arranged in a matrix next to each other or partially overlapping, which matrix contours at least a portion of the dental arch. Furthermore, the matrix can have a regular or irregular arrangement of the plurality of signal conductors. Furthermore, it is conceivable that a plurality of signal conductor grids are arranged in the matrix.

[0029] By using the signal conductor array, the coverage of the relevant anatomy with the signal conductors can be improved in an advantageous manner. Thereby, the signal-to-noise ratio can be increased and the image quality of the magnetic resonance examination can be improved. Furthermore, when using a plurality of reception channels, parallel imaging algorithms can be used which reconstruct image data of the examination object from undersampled k-space data and enable a reduction of the measurement duration of the magnetic resonance measurement.

[0030] According to a further embodiment of the antenna array according to the application, at least a portion of the signal conductor array is oriented along a plane of the occlusal surface of the examination object. The signal conductor array can have a matrix of adjacent or partially overlapping loops as described above. The signal conductor array preferably has a shape which fits to the dental arch of the examination object, for example a U-shape or a horseshoe shape. It is conceivable that the signal conductor array between the dental arch of the upper jaw and the dental arch of the lower jaw can be positioned along the plane of the occlusal surface of the dental arch. The signal conductor array here preferably has an approximately planar extension which enables imaging in an approximately occlusal position of the dental arch. Preferably, at least a portion of the dental arch which is relevant for imaging is covered by the antenna array along the occlusal surface. However, it is also conceivable that the signal conductor together with the carrier element is arranged in a position which is selected according to the application in contact with the dental arch of the upper jaw or the lower jaw of the examination object.

[0031] By positioning the signal conductor array along the occlusal surface of the dental arch, the sensitivity distribution of the antenna array in the area of the teeth and / or the dental neck can be improved. At the same time, the sensitivity distribution of the antenna array in the area of the movable cheek and tongue can be reduced, thereby suppressing image artifacts in an advantageous manner. Furthermore, the improved sensitivity distribution in the area of the teeth and / or the dental neck in the occlusal position of the full set of teeth can be used in an advantageous manner for imaging of both dental arches of the examination object.

[0032] In a further embodiment of the antenna array according to the application, at least a portion of the signal conductor array is oriented in an orientation perpendicular to the plane of the occlusal surface at the inner side of the teeth of the dental arch. The orientation perpendicular to the plane of the occlusal surface can point, for example, in the direction of the hyoid bone of the examination object or in the direction of the palate of the examination object from the plane of the occlusal surface. It is conceivable that the signal conductor array in the position of the carrier element according to the application is positioned on the inner side of the teeth of the examination object on the full set of teeth of the examination object. The inner side of the teeth of the dental arch is preferably at least partially surrounded here by the signal conductor array. The signal conductor array can also protrude a portion of the gum of the examination object. It is thus conceivable that the signal conductor array surrounds the entire inner side of the teeth of the dental arch from the plane of the occlusal surface up to the protrusion of the gum, but also a portion of the gum. The signal conductor array is preferably oriented approximately parallel to the inner side of the teeth. The dental arch here can be either the dental arch of the lower jaw or the dental arch of the upper jaw. It is also conceivable that the signal conductor array in the position of the carrier element according to the application is positioned both on the inner side of the teeth of the upper jaw and on the inner side of the teeth of the lower jaw.

[0033] By positioning the signal conductor array on the inner tooth surface of the examination object, the full set of teeth of the examination object can be surrounded by the signal conductors from multiple sides in an advantageous manner. The signal-to-noise ratio of the magnetic resonance measurement can thereby be increased, and the image quality can be improved. Furthermore, by positioning the signal conductor array on the inner tooth surface, a minimum spacing from the full set of teeth can be established with as large a spacing as possible from the movable cheek. By positioning the signal conductor array on the inner tooth surface, the freedom of movement of the tongue can be further limited, whereby image artifacts due to movement of the tongue are reduced in an advantageous manner.

[0034] In a further embodiment of the antenna array according to the application, at least a portion of the signal conductor array is oriented in an orientation perpendicular to the plane of the occlusal surface on the outer side of the dental arch. It is conceivable that the signal conductor array in the position of the carrier element according to the application is positioned on the full set of teeth of the examination object on the outer side of the teeth of the examination object. The outer side of the teeth is preferably at least partially surrounded here by the signal conductor array. The signal conductor array can also protrude from a portion of the gum of the examination object. The signal conductor array is preferably oriented approximately parallel to the outer tooth surface. It is conceivable that the signal conductor array is molded around the entire outer tooth surface of the dental arch from the plane of the occlusal surface up to the protrusion of the gum, but also beyond the outer tooth surface. The dental arch can here be either the dental arch of the lower jaw portion or the dental arch of the upper jaw portion. It is likewise conceivable that the signal conductor array in the position of the carrier element according to the application is positioned both on the outer tooth surface of the upper jaw portion and on the outer tooth surface of the lower jaw portion.

[0035] By positioning the signal conductor array on the outer tooth surface of the examination object, the full set of teeth of the examination object can be surrounded by the signal conductors from multiple sides in an advantageous manner. The signal-to-noise ratio of the magnetic resonance measurement can thereby be increased, and the image quality can be improved. Furthermore, compared to the inner tooth surface, the outer tooth surface generally has a larger and / or more uniform surface, which enables an advantageous distribution of the signal conductor array. Thereby, an improved signal reconstruction can be achieved when using accelerated parallel imaging methods, such as iPAT (integrated parallel acquisiton techniques) or SMS (simultaneous multi slicing).

[0036] According to one embodiment of the antenna array according to the application, the carrier element at least along the tooth side on which the signal conductor or the signal conductor array is positioned, in the position according to the application, encloses the dental arch of the examination object. The tooth side can be, for example, the inner tooth side, the outer tooth side, the bite side of the dental arch or a part of the dental arch. It is conceivable that the carrier element encloses the dental arch on all sides on which the signal conductor or the signal conductor array is positioned. The carrier element preferably extends approximately parallel along the tooth side here. This can mean that at least a part of the carrier element is oriented parallel to the bite side, the inner tooth side and / or the outer tooth side of the dental arch. It is likewise conceivable that the carrier element contours the dental arch by enclosing the dental arch from one, two or more sides of the dental arch. The signal conductor or the signal conductor array is preferably stabilized or supported by means of the connection to the carrier element along the tooth side.

[0037] In the described embodiment, the signal conductor or the signal conductor array is positioned on a side of the carrier element which, in the position according to the application, faces the dental arch. This can mean that the signal conductor or the signal conductor array is positioned on a side of the carrier element which contours the full set of teeth of the examination object. As described above, the signal conductor or the signal conductor array can be connected to the carrier element here in an arbitrary manner, form-fitting, force-fitting or material-fitting. It is likewise conceivable that the signal conductor or the signal conductor array is inserted into the carrier element and clamps between the dental arch and the carrier element when connected to the full set of teeth.

[0038] By enclosing one or more sides of the dental arch by the carrier element, a form-fitting connection between the carrier element and the full set of teeth of the examination object can be achieved in an advantageous manner. Furthermore, the signal conductor or the signal conductor array can be fastened in the position according to the application on the full set of teeth of the examination object in an advantageous manner form-stable by the connection to the carrier element and can prevent the examination object from moving during the magnetic resonance examination.

[0039] According to a further embodiment of the antenna array according to the application, the carrier element has a plastic block on the side facing the dental arch in the position according to the application, which can be deformed upon contact with the full set of teeth of the examination object. The plastic block is preferably plastically deformable. This can mean that the plastic block permanently retains the shape obtained as a result of the deformation. The plastic block can be deformed permanently or within a predetermined time window. For example, it is conceivable that the plastic block hardens within a predetermined time by contact with air oxygen or by the addition of a hardening component. The plastic block can be produced by mixing, for example, prior to the magnetic resonance examination. Preferably, the plastic block has a deformation resistance that is sufficiently low to enable manual deformation and / or deformation by the full set of teeth of the examination object at temperatures between 15°C and 40°C. The material of the plastic block is preferably biocompatible. In addition to the materials mentioned above, plastic blocks based on plaster, wax, hydrocolloids, silicone and polyether are primarily conceivable. The plastic block preferably molds the dental arch in the position according to the application of the carrier element. This can mean that the plastic block deforms three-dimensionally upon connection with the dental arch and surrounds the dental arch from multiple sides. It is conceivable that the plastic block surrounds the dental arch via a continuous section or at multiple discontinuous locations. It is likewise conceivable that the plastic block surrounds the entire dental arch. The plastic block can be connected with the dental arch of the mandible, with the dental arch of the maxilla or with both dental arches in the position according to the application of the carrier element.

[0040] It is conceivable that the plastic block coats the surface of the carrier element facing the dental arch in the position according to the application of the carrier element. The signal conductor of the antenna array can here be positioned, for example, between the dental arch and the plastic block or between the plastic block and the carrier element. It is however likewise conceivable that the plastic block is the carrier element or a part of the carrier element with which the antenna array is connected in the position according to the application with the full set of teeth of the examination object. In this case, the signal conductor can be positioned both between the dental arch and the plastic block and on the side of the plastic block facing away from the dental arch.

[0041] By using a plastic block, the carrier element can be connected in a favorable manner in positive engagement with an arbitrarily shaped full set of teeth. Thereby the effort to manufacture individually adapted carrier elements can be reduced.

[0042] In a further embodiment of the antenna array according to the application, the carrier element has a recess for accommodating the dental arch and a holding device for fastening the signal conductor or the array of signal conductors, wherein the signal conductor or the array of signal conductors is supported above the recess by means of the holding device and is molded onto the full set of teeth of the examination object by being positionable according to the application of the carrier element on the full set of teeth of the examination object.

[0043] The recess can be, for example, a recess, a flexure or a depression in the carrier element, which has a suitable geometry to accommodate the dental arch of the examination subject. A suitable geometry is, in particular, a recess having a "U"-shaped cross section, a "V"-shaped cross section, a "C"-shaped cross section or a recess having an arbitrary shaped cross section, which can be obtained by a twisting or a deformation of the mentioned shapes. The recess is preferably configured circumferentially in the carrier element, so that at least a portion of the dental arch is accommodated by the recess in a position depending on the application.

[0044] The holding device can be any connecting element suitable for fastening the signal conductor or the array of signal conductors. Possible examples of holding devices are hangers, such as hooks or eyelets, as well as adhesive connections, hook-and-loop fasteners, locking devices and the like. The holding device preferably has a releasable connecting element, which enables a reversible connection of the signal conductor or the array of signal conductors to the carrier element.

[0045] The signal conductor or the array of signal conductors is preferably connected to the holding device at least at two points. The holding device is preferably positioned on the carrier element, so that the signal conductor or the array of signal conductors is supported above the recess of the carrier element by the application-dependent connection to the holding device.

[0046] It is conceivable that the signal conductor or the array of signal conductors is fastened to the holding device with an elastic element, for example a spring or a rubber band. Thereby, the signal conductor or the array of signal conductors can be deflected from a portion of the dental arch into the recess of the carrier element under strain of the elastic element, when the carrier element is positioned on the dental arch depending on the application. By means of a pulling force exerted by the extension of the elastic element, the signal conductor or the array of signal conductors is preferably molded onto the occlusal surface, the inner tooth surface and the outer tooth surface of the dental arch, so that the signal conductor or the array of signal conductors arranged in the recess surrounds the dental arch from all sides. The signal conductor or the array of signal conductors preferably has sufficient plastic and / or elastically deformable properties here. To this end, the signal conductor or the array of signal conductors can comprise elastic, movable and / or movable relative to each other elements.

[0047] Furthermore, the signal conductor or the array of signal conductors and / or the holding device can also have a rolling or folding mechanism, which constitutes a deflection of the signal conductor or the array of signal conductors when coming into contact with the dental arch. Furthermore, the holding device can also have any elastic system, for example a pneumatic or hydraulic spring system, for fastening the signal conductor or the array of signal conductors.

[0048] By using the elastic fastening of the signal conductor or the array of signal conductors, the antenna array can be advantageously molded onto the dental arch when connecting the carrier element to the full set of teeth of the examination subject. Thereby, the spacing between the signal conductor or the array of signal conductors and the dental arch can be advantageously reduced. In this way, an improved signal-to-noise ratio of the magnetic resonance measurement can be achieved.

[0049] In a further embodiment of the antenna array according to the application, at least a portion of the antenna array is positioned along a portion of the palate and / or hyoid bone of the examination object in a position according to the application. It is conceivable that, as described above, the antenna array at least surrounds a portion of the gingiva of the examination object. The antenna array can in a similar manner surround the inner side of the teeth from the bite surface of the examination object up to the palate and / or hyoid bone of the examination object. It is particularly conceivable that the carrier element has an arc-shaped structure which is profiled to the palate and / or hyoid bone of the examination object and is connected to the palate and / or hyoid bone in a position of the carrier element according to the application. The arc-shaped structure can have a flexible material, for example an elastomer based on rubber or silicone, which can be molded onto the palate and / or hyoid bone when the carrier element is connected to the full set of teeth.

[0050] The arc-shaped structure of the carrier element can be connected to a signal conductor or to an array of signal conductors and positions it at least along a portion of the palate and / or hyoid bone. It is conceivable that the signal conductor or the array of signal conductors is deformable as described above and adapts to the shape of the palate or hyoid bone of the examination object. The signal conductor or the array of signal conductors can also be molded onto the palate and / or hyoid bone of the examination object by means of the tongue of the test object. The tongue can lie both against the palate and against the hyoid bone of the examination object in a natural resting position and mold the deformable signal conductor or the deformable array of signal conductors onto the palate and / or hyoid bone. The carrier element preferably has a recess at least in the region of the floor of the mouth and / or the base of the tongue in order to avoid a tightening or constriction of the tongue.

[0051] By positioning the signal conductor or the array of signal conductors in the region of the palate and / or hyoid bone of the examination object, the sensitive region of the antenna array can in an advantageous manner extend to the entire region of the oral cavity.

[0052] According to a further embodiment of the antenna array according to the application, the antenna array has at least one electrically conductive shield which is positioned between the antenna array and the soft tissue of the examination object in a position of the antenna array according to the application and constitutes a radio frequency signal for shielding from the direction of the soft tissue.

[0053] The electrically conductive shield preferably has an electrically conductive metal, for example gold, silver or aluminum. It is likewise conceivable that the electrically conductive shield has a base body of any non-magnetic material which is coated or electroplated with an electrically conductive material. The electrically conductive shield particularly constitutes a radio frequency signal for shielding from the direction of the soft tissue towards the antenna array.

[0054] The soft tissue can be, for example, the tongue, the cheek or the lips of the examination object. The radio frequency signals of the soft tissue are preferably guided away by the electrically conductive shield in order to reduce the interaction of such signals with the antenna array. The electrically conductive shield is positioned for this purpose between the antenna array and the soft tissue. This can mean, for example, that the electrically conductive shield is positioned in the intermediate space between the tooth outer side of the dental arch and the cheek of the examination object. It is likewise conceivable that the electrically conductive shield is positioned between the tooth inner side of the examination object and the tongue.

[0055] The electrically conductive shield can be connected in one piece with the carrier element of the antenna array or fastened on the carrier element. The electrically conductive shield can also have an electrical connection to the antenna array and / or to the ground of the magnetic resonance device. It is likewise conceivable that the electrically conductive shield is separated from the antenna array and / or from other electrically conductive components in the position according to the application.

[0056] By using the electrically conductive shield, radio frequency signals from movable regions of the oral cavity, for example the cheeks or the tongue of the examination object, can be shielded in an advantageous manner. Image artifacts can thereby be avoided and the quality of the image data is improved.

[0057] The system according to the application comprises a magnetic resonance device and an antenna array, wherein the magnetic resonance device has a signal connection to the antenna array and constitutes a means for receiving radio frequency signals of the antenna array and creating image data of the full dentition of an examination object. The signal connection between the antenna array and the magnetic resonance device is preferably implemented as a shielded electrical connection line. The electrical connection line can furthermore have further components, for example electronic circuits, receivers and / or amplifiers. It is likewise conceivable that the signal connection between the antenna array and the magnetic resonance device is implemented wirelessly. For this purpose, the antenna array can have a transmitter, as described above, which communicates with a corresponding receiver of the magnetic resonance device. The communication can take place here via directional or non-directional electromagnetic waves. Possible transmission methods can include, for example, transmission via radio or optical directional radio. It is also conceivable that the antenna array is positioned, recognized and / or initialized by means of a wireless signal connection. The corresponding signal connection can be realized, for example, via an RFID system.

[0058] The magnetic resonance device preferably has a holding element with which the antenna array and / or the carrier element is held in the position according to the application on the full dentition of the examination object. According to one of the above-mentioned embodiments, the holding element can also be connected with the carrier element here. The holding element preferably has an adjustment mechanism with which the orientation of the antenna array and / or the carrier element can be changed in at least two spatial directions.

[0059] It is also conceivable that the magnetic flux density and / or the orientation of the main magnetic field B0is coordinated with the antenna array. This can mean, in particular, that the antenna array and / or the signal conductor or signal conductor array is oriented approximately orthogonally to the orientation of the main magnetic field B0in the position according to the application.

[0060] Image data of a magnetic resonance measurement can be obtained by means of a multiple Fourier transformation of measurement data (k-space data) of an examination object. For the recording of k-space data, the orientation of atomic nuclei in an examination object is modulated with respect to a static magnetic field Bo in the x-direction, the y-direction and the z-direction, and radio frequency signals of the atomic nuclei are detected by means of at least one signal conductor. By means of a modulation in the z-direction, the atomic nuclei of individual layers of the examination object can be assigned a specific radio frequency pulse which can be used for layer selection. The modulation in the x-direction and the y-direction can impose an additional frequency gradient and a phase gradient on the atomic nuclei, so that the received radio frequency signals can be associated with volume elements in the examination object. Usually, the sum signal of the horizontal spatial frequencies is then entered into the horizontal rows of a matrix, while the sum signal of the vertical spatial frequencies is entered into the vertical columns of the matrix. The matrix is usually referred to as k-space and represents the measurement data of a magnetic resonance measurement.

[0061] By combining a magnetic resonance device and an antenna array in a system according to the application, an improved signal transmission and an improved mechanical and / or electrical integration of the antenna array with the magnetic resonance device can be achieved. When using a dedicated holder for the antenna array and / or the carrier element, the positioning of the antenna coil in the imaging region of the magnetic resonance device can be provided in an advantageous manner which is optimized with respect to the geometry of the magnetic resonance device.

[0062] In a further embodiment of the system according to the application, the magnetic resonance device comprises a plurality of receiving channels having a plurality of signal connections to the signal conductor array. For example, the plurality of receiving channels can mean that the receiver of the magnetic resonance device has a plurality of physical interfaces which are electrically connected to the antenna array or to the signal conductor array of the antenna array. It is conceivable that exactly one signal conductor of the signal conductor array is connected to exactly one receiving channel of the receiver of the magnetic resonance device. However, it is also conceivable that a plurality of signal conductors are connected to one receiving channel.

[0063] By using a plurality of receiving channels for receiving the magnetic resonance signals of the signal conductor array, the signal-to-noise ratio of the magnetic resonance measurement can be improved in an advantageous manner. Furthermore, methods for reconstructing image data from reduced k-space data can be used, which reduce the measurement duration required for recording the image data in an advantageous manner.

[0064] In a method for performing a magnetic resonance measurement of a full dentition of an examination object with an antenna array according to the application, the antenna array is connected to the full dentition of the examination object in a predetermined relative position.

[0065] In one step of the method according to the application, the carrier element with the antenna array is oriented relative to the full set of teeth in the oral cavity of the examination object, wherein the side of the carrier element which is shaped to the full set of teeth of the examination object is oriented in the direction towards the full set of teeth. As mentioned above, the carrier element has at least one side which is shaped to the shape of the dental arch of the examination object. The side of the carrier element which is shaped to the full set of teeth is oriented in the direction towards the full set of teeth can be understood as meaning that the carrier element is placed in an orientation which at least approximately coincides with the position according to the application on the full set of teeth of the examination object. The orientation can here deviate from the position according to the application in each spatial direction in order to make it easier for the carrier element to be introduced into the oral cavity and / or for the carrier element to be positioned in the oral cavity of the examination object. It is conceivable, for example, that the carrier element is twisted or turned relative to the position according to the application in order to make the introduction into the oral cavity easier.

[0066] By using a carrier element which is shaped to the full set of teeth, the carrier element can be connected to the full set of teeth only in a predetermined orientation. The positioning according to the application of the carrier element can be determined from the outer configuration of the carrier element, whereby an incorrect positioning of the antenna array is advantageously avoided.

[0067] In a further step of the method according to the application, the carrier element is connected to the full set of teeth of the examination object in the position according to the application. The connection is made by bringing the side of the carrier element which is shaped to the full set of teeth of the examination object into contact with the full set of teeth.

[0068] It is conceivable that the carrier element plastically deforms upon connection with the full set of teeth in order to obtain a form-fit connection with the full set of teeth. However, it is also conceivable that a part of the deformation of the carrier element is an elastic deformation. By means of the elastic deformation of the carrier element, an elastic restoring force of the carrier element can act on the surface of the full set of teeth and force-fit the carrier element to the full set of teeth. As mentioned above, the carrier element preferably has a recess for accommodating the dental arch. The recess can engage with the dental arch in the position of the carrier element according to the application in order to limit the relative movement between the carrier element and the dental arch along the plane of the occlusal surface. However, it is also conceivable that the cross section of the recess is smaller than the corresponding cross section of the dental arch, so that the carrier element deforms upon connection with the full set of teeth. By means of the deformation of the carrier element, a form-fit connection of the carrier element to the full set of teeth can be obtained, as mentioned above. The deformation can also have an elastic part which can realize a force-fit connection to the full set of teeth. The at least one signal conductor of the antenna array can be positioned on the side of the carrier element which faces the full set of teeth in the position of the carrier element according to the application. Thereby, the at least one signal conductor can be positioned with as small a distance as possible with respect to the full set of teeth of the examination object. Instead of the at least one signal conductor, the antenna array can also have an array of signal conductors according to one of the above-mentioned embodiments. Upon connection of the carrier element to the full set of teeth, the signal conductor or the array of signal conductors is preferably positioned in the position according to the application along the occlusal surface, the inner side of the teeth and / or the outer side of the teeth, as mentioned above.

[0069] By contacting the side of the carrier element which is shaped to the full set of teeth with the full set of teeth of the examination object, it is possible in an advantageous manner to avoid an elaborate positioning of the antenna array on the full set of teeth of the examination object. Thereby, the duration of the preparation of the magnetic resonance measurement can be reduced and the comfort of the examination object can be increased.

[0070] In a further step of the method according to the application, a magnetic resonance measurement is performed on the full dentition of the examination object, wherein the antenna array detects radio frequency signals by means of the at least one signal conductor and transmits the radio frequency signals to a receiver of the magnetic resonance device. Performing the magnetic resonance measurement preferably comprises implementing an imaging sequence adapted for imaging of the teeth. Possible imaging sequences can for example have a very short echo time in order to compensate for the short T2 relaxation time of the spins of the dentin or the enamel of the teeth and to display the regions in the image data in a signal intensity manner. The very short echo time can for example be less than 150 μβ or less than 70 μβ. Possible imaging sequences are for example FLASH (fast low-angle shot) or UTE (ultra-short echo time) sequences. However, it is also conceivable to use imaging sequences with a longer echo time, for example TSE (turbo spin echo) sequences. In the case of such sequences, the magnetic resonance signals of the enamel or the dentin can be avoided from being detected. In the image data of such imaging sequences, the teeth can for example be distinguished by the missing signal intensity in contrast to the surrounding tissue. In imaging sequences with both a short echo time and a longer echo time, the antenna array is preferably positioned by means of the carrier element immediately adjacent to the medically relevant anatomical structure in order to detect the magnetic resonance signals of the low-signal volume of the oral cavity of the examination object. The antenna array can here have both a single signal conductor and an array of signal conductors. When the carrier element is connected to the full dentition of the examination object, the signal conductor or the array of signal conductors is preferably positioned such that a high coverage of the signal volume of the relevant anatomical structure is achieved.

[0071] By positioning the antenna array immediately adjacent to the relevant anatomical structure of the examination object, it is also possible in an advantageous manner to utilize the antenna array for detecting small signals and for using them for image reconstruction when performing the magnetic resonance measurement.

[0072] In one embodiment of the method according to the application, the plastic block of the carrier element is deformed when connected to the full dentition and constitutes a form-fitting connection to the full dentition of the examination object, which reversibly fastens the carrier element on the full dentition. As mentioned above, the carrier element can have a plastic block on the side facing the dental arch in the position according to the application, which molds the dental arch of the examination object. The plastic block is here preferably coated in a recess of the carrier element, which constitutes a recess for surrounding the dental arch of the examination object from at least one side. Thereby, the plastic block can be supported on at least one side by the carrier element, so that the plastic block can mold at least one side of the dental arch.

[0073] It is also conceivable that the plastic block is the carrier element. In this case, the signal conductor or the array of signal conductors can be positioned on the side of the plastic block which, in the position according to the application, faces towards the dental arch or away from the dental arch. Furthermore, the signal conductor or the array of signal conductors can also be embedded in the plastic block. The plastic block can surround the entire dental arch in the position according to the application or be connected to the dental arch point by point, i.e. at individual discontinuities. The plastic block preferably copies the shape of the dental arch. This can mean that the plastic block already has a U-shaped or horseshoe-shaped configuration before being connected to the full set of teeth of the examination object.

[0074] The plastic block is preferably reversibly connected to the full set of teeth of the examination object and, after the typical duration of a magnetic resonance examination, for example 5 minutes, 10 minutes, 15 minutes or 30 minutes, can be detached from the full set of teeth manually or with suitable apparatus. It is conceivable that the plastic block comprises one of the materials mentioned above.

[0075] By using the plastic block, the carrier element can be molded to the individual geometry of the full set of teeth of the examination object. In this way, it can be advantageously avoided that the carrier element is laboriously adapted to different bite sizes. Furthermore, by molding the plastic block to the full set of teeth of the examination object, a form-fitting connection to the full set of teeth can be obtained, which advantageously avoids relative movements between the antenna array and the full set of teeth of the examination object, for example due to involuntary movements of the tongue, cheek or jaw of the examination object.

[0076] In one embodiment, the method according to the application has a further step in which the carrier element is detached from the full set of teeth of the examination object and a positive mold of the full set of teeth of the examination object is created on the basis of the plastic block of the carrier element. The positive mold can be a true model of the full set of teeth of the examination object, which can be used, for example, as a tooth impression for the manufacture of a denture. It is conceivable that the positive mold of the full set of teeth is obtained from a negative mold of the plastic block of the carrier element. To this end, the plastic block, which has an impression of the full set of teeth of the examination object after being molded onto the full set of teeth of the examination object, can be removed from the full set of teeth of the examination object and filled with an arbitrary molding compound.

[0077] By using the plastic block for connecting the carrier element to the full set of teeth of the examination object, a magnetic resonance measurement can be combined with the creation of a tooth impression in an advantageous manner. By creating image data of the examination object and a tooth impression in parallel, the workflow of a dental practice can be optimized in an advantageous manner and treatment costs can be reduced.

[0078] In another embodiment of the method according to the application, the signal conductor or the signal conductor array is supported above the recess of the carrier element by means of a holding device, and is deflected in the direction of the recess of the carrier element by at least a portion of the dental arch when the carrier element is connected with the full set of teeth, wherein the at least a portion of the dental arch is surrounded by the signal conductor or the signal conductor array along the free surface.

[0079] In said embodiment, as mentioned above, the signal conductor or the signal conductor array can have deformable or movable elements relative to one another, which allow molding onto the dental arch of the examination object. The holding device preferably also has elastically deformable elements on which the signal conductor or the signal conductor array is supported or suspended. It is conceivable that the signal conductor or the signal conductor array is stretched over the free surface of the dental arch when deflected in the direction of the recess, so that the signal conductor or the signal conductor array surrounds the dental arch. The free surface of the dental arch can for example be the tooth contour following the tooth surface along the inner tooth side, the bite surface and the outer tooth side.

[0080] As mentioned above, the signal conductor or the signal conductor array preferably has a coating and / or a shielding made of electrically and / or thermally insulating material in order to avoid damaging the teeth or injuring the examination object.

[0081] It is conceivable that the signal conductor or the signal conductor array is permanently pressed into the recess of the carrier element by means of the bite force of the examination object. Preferably, however, the reset force of the jaw muscles of the examination object is utilized in order to hold the signal conductor or the signal conductor array in the recess of the carrier element. To this end, the two dental arches of the examination object can be spaced apart from one another by means of the carrier element to such an extent that the natural reset force of the jaw muscles pulls the two dental arches onto one another and presses the signal conductor or the signal conductor array into the recess of the carrier element. The spacing apart between the two dental arches can for example be realized by means of an arbitrary shaped spacing holder positioned between the two dental arches. The spacing holder is preferably connected in one piece with the carrier element. However, a separate embodiment of the spacing holder from the carrier element is also conceivable.

[0082] By stretching the signal conductor or the signal conductor array over the dental arch of the examination object, the antenna array can be adapted in an advantageous manner to the arbitrary geometry of the dental arch. Thereby it can be avoided that the carrier element is expensively adapted to a plurality of possible full set of teeth shapes.

[0083] In another embodiment of the method according to the application, the magnetic resonance measurement is performed with a plurality of receiving channels which receive the magnetic resonance signals from the signal conductor array, wherein in order to reduce the measurement duration of the magnetic resonance measurement, a reduced number of k-space data is detected, and a parallel imaging method is used in order to reconstruct the image data of the full set of teeth from the reduced number of k-space data.

[0084] It is conceivable that a plurality of receiving channels simultaneously detect a plurality of magnetic resonance signals of the signal conductor array. The individual signal conductors in the signal conductor array preferably have different spatial sensitivities here, which can be used as additional encoding for reconstructing the image data. The detection of a reduced number of k-space data is preferably achieved by reducing the number of phase-encoding steps in the imaging sequence. This can result in a reduction of the imaging region at constant image resolution. Anatomical structures having a size greater than the reduced imaging region can here cause a roll-off artifact, which can be removed by using a reconstruction method for parallel imaging. It is conceivable that a reconstruction method using the data of the reconstructed k-space is used. Possible reconstruction methods are, for example, SMASH (simultaneous acquisition of spatial harmonics), GRAPPA (generalized auto-calibrating partially parallel acquisitions), PILS (parallel imaging with localized sensitivities) and SENSE (sensitivity encoding). However, it is equally conceivable that the reconstruction method comprises a Fourier transformation of the k-space data. Furthermore, it is also possible to use an SMS (simultaneous multi-slice) imaging method in order to accelerate the detection of the k-space data.

[0085] By receiving a plurality of magnetic resonance signals of the signal conductor array by means of a plurality of receiving channels, the number of detected k-space data can be reduced and the image data can be reconstructed by means of a parallel imaging method. Thereby, the measurement duration of the magnetic resonance measurement can be reduced in an advantageous manner. This can improve the comfort of the examination object and can improve the economic efficiency and the execution of the magnetic resonance-based imaging method compared to existing systems based on ionizing radiation. BRIEF DESCRIPTION OF DRAWINGS

[0086] Further advantages and details result from the following description of embodiments in conjunction with the attached drawings. In the principle diagram:

[0087] Figure 1 One possible embodiment of a system according to the application is shown,

[0088] Figure 2 One possible embodiment of an antenna array with plastic blocks according to the application is shown,

[0089] Figure 3 One possible embodiment of an antenna array with plastic blocks according to the application is shown,

[0090] Figure 4 A possible embodiment of an antenna array according to the application is shown,

[0091] Figure 5 A possible embodiment of an antenna array according to the application is shown,

[0092] Figure 6 A possible embodiment of an antenna array according to the application is shown,

[0093] Figure 7 A possible embodiment of an antenna array according to the application is shown,

[0094] Figure 8 A possible embodiment of an antenna array according to the application is shown,

[0095] Figure 9 A possible embodiment of an antenna array according to the application is shown,

[0096] Figure 10 A possible embodiment of an antenna array according to the application is shown,

[0097] Figure 11 A possible embodiment of an antenna array according to the application is shown,

[0098] Figure 12 A possible flow chart of a method according to the application is shown. DETAILED DESCRIPTION

[0099] In the following description of the figures, a human patient is referred to as the examination object, since this is a common application case for magnetic resonance-based imaging methods. Of course, this does not exclude the above-mentioned examples of examination objects.

[0100] In Figure 1 An embodiment of a system with a magnetic resonance device 10 and an antenna array 26 is shown schematically in Fig. 1. The magnetic resonance device 10 comprises a magnet unit 11, for example with a permanent magnet, an electromagnet or a superconducting main magnet 12 for generating a strong and in particular uniform main magnetic field 13 (static magnetic field Bo). Furthermore, the magnetic resonance device 10 comprises a patient receiving area 14 for accommodating a patient. In the present embodiment, the patient receiving area 14 is cylindrically configured and is surrounded in the circumferential direction by the magnet unit 11. However, a different configuration of the patient receiving area 14 than the example described is also conceivable in principle.

[0101] A patient can be positioned in the patient receiving area 14 by means of a patient support device 16 of the magnetic resonance device 10. The patient support device 16 for this has an examination bed 17 which is configured to be movable within the patient receiving area 14. The magnet unit 11 also has gradient coils 18 for generating magnetic field gradients, which are used for position encoding during imaging. The gradient coils 18 are actuated by means of a gradient control unit 19 of the magnetic resonance device 10. The magnet unit 11 can also comprise a radio frequency antenna, which in the present embodiment is embodied as a body coil 20 which is fixedly integrated into the magnetic resonance device 10. The body coil 20 is designed for exciting atomic nuclei which are in a main magnetic field 13 generated by a main magnet 12. The body coil 20 is actuated by a radio frequency unit 21 of the magnetic resonance device 10 and emits radio frequency signals into an examination space which is essentially formed by the patient receiving area 14 of the magnetic resonance device 10. The body coil 20 also constitutes a receiver for receiving magnetic resonance signals.

[0102] For controlling the main magnet 12, the gradient control unit 19 and for controlling the radio frequency unit 21, the magnetic resonance device 10 has a control unit 22. The control unit 22 constitutes a control unit for controlling the execution of sequences, for example imaging gradient echo sequences, TSE sequences or UTE sequences. Furthermore, the control unit 22 comprises an evaluation unit 28 for evaluating digitized magnetic resonance signals detected during a magnetic resonance examination. The evaluation unit can likewise constitute a reconstruction method for reconstructing image data from a reduced number of k-space data when using parallel imaging methods.

[0103] Furthermore, the magnetic resonance device 10 comprises a user interface 23 which has a signal connection to the control unit 22. Control information, for example imaging parameters and reconstructed magnetic resonance images, can be displayed for a user on a display unit 24 of the user interface 23, for example on at least one monitor. Furthermore, the user interface 23 has an input unit 25 by means of which parameters of a magnetic resonance measurement can be input by a user. Furthermore, the magnetic resonance device 10 has an antenna array 26 which is positioned on the full dentition of the examination object 15 and transmits magnetic resonance signals from the oral cavity to the magnetic resonance device 10. The antenna array 26 preferably has an electrical connection line 27 which provides a signal connection to the radio frequency unit 21 and to the control unit 22. Like the body coil 20, the antenna array 26 can also constitute a receiver for receiving magnetic resonance signals. For this, the antenna array 26 can in particular have a cylindrical configuration which encloses the head of the patient 15. For emitting radio frequency signals, the antenna array 26 is actuated by the radio frequency unit 21.

[0104] The illustrated magnetic resonance device 10 can of course comprise further components which are generally present in a magnetic resonance device. It is likewise conceivable for the magnetic resonance device 10 to have a C-shaped configuration, a triangular configuration or an asymmetric configuration instead of a cylindrical configuration with the components for generating the magnetic field. The magnetic resonance device 10 can in particular be configured for performing a magnetic resonance examination of a patient 15 in a standing or sitting position.

[0105] Figure 2 One embodiment of the antenna array 26 is shown in which the antenna array 26 is connected to the dental arch 31 of the upper jaw of the patient 15 by means of a plastic block 34. In the example shown, a suitably shaped applicator 35 is used in order to connect the antenna array 26 with the plastic block 34 to the dental arch 31 of the patient 15 in a position which is dependent on the application. The plastic block 34 here represents a carrier element which connects the antenna array 26 to the full set of teeth 30 of the patient in a form-fitting manner. For this purpose, the plastic block 34 is applied at a plurality of interrupted locations of the antenna array 26. In the embodiment shown, the antenna array 26 has a horseshoe shape which imitates the shape of the dental arch 31. In order to protect the patient 15, the antenna array 26 is covered with an electrically and thermally insulating material.

[0106] Figure 3 One alternative embodiment of the antenna array 26 is shown in which the antenna array 26 is connected to the dental arch 31 of the upper jaw and the lower jaw of the patient 15 by means of a plastic block 34. In the example shown, the antenna array 26 is fastened on a holder 33 which has adjustment mechanisms for adapting the orientation of the antenna array 26 in all three spatial directions. Not only the applicator 35 but also the holder 33 can be suitable for guiding the signal conductors of the antenna array 26 out of the oral cavity 32 of the patient 15 and / or for providing a connection to the electrical connection line 27. For this purpose, for example, strain relief for the electrical connection line 27 and / or the signal conductors of the antenna array 26 can be proposed.

[0107] Figure 4An embodiment of an antenna array 26 is shown with a non-plastic carrier element 36. The carrier element 36 contours the dental arch 31 of the patient 15 and has a surrounding wall 38 which in the position according to the application is positioned on the tooth outer side of the dental arch 31 and limits the movement of the carrier element 36 along the plane of the occlusal surface. The carrier element 36 also has a recess 39 which in the position according to the application accommodates the dental arch 31 of the patient. An arc-shaped structure 40 of the carrier element 36 in the position according to the application is located on the palate of the patient 15 and limits the movement of the carrier element 36 in the direction towards the tooth inner side of the dental arch 31. In the shown example, the carrier element 36 contours the dental arch 31 of the patient 15 and thus a form-fitting connection of the antenna array 26 to the full set of teeth 30 of the patient 15 can be achieved. It is conceivable that the recess 39 additionally has a plastic block 34 which improves the form-fitting connection between the dental arch 31 and the antenna array 26. In the shown example, the antenna array 26 has a single loop of signal conductors 37 which extend along the recess 39 and in the position according to the application are positioned on the occlusal surface of the dental arch 31.

[0108] Figure 5 An alternative embodiment of an antenna array 26 is shown in which the carrier element 36 surrounds a portion of the dental arch 31. In the shown example, the carrier element 36 surrounds a quarter of the dental arch 31 which generally comprises two incisors, one canine and the premolar and molar teeth. Other configurations of the carrier element 36 are conceivable which surround individual sections of one or more quarters of the dental arch 31, in addition to the shown example. As in the embodiment shown in Figure 4 The loop of signal conductors 37 is placed into the recess 39 in the embodiment shown in. The loop has a deflection of 180° on the side of the carrier element 36 which in the direction according to the application is towards the throat of the patient 15, so that the signal conductors 37 are placed into the recess 39 in a double line. This can improve the sensitivity of the antenna array 26 in the area of the dental arch 31 which is surrounded. But it is also conceivable that sections of the signal conductors 37 are guided back into the recess 39 or outside of the carrier element 36 in order to close the loop.

[0109] Figure 6One embodiment of the antenna array 26 is shown, in which the signal conductor array 40 is positioned in the recess 39 of the carrier element 36. In the example shown, the signal conductor array 40 has an array or matrix of circular rings which are adjacent to one another and partially overlap. However, the signal conductor array 40 can also have a grid structure and any linear or nonlinear arrangement of the signal conductors 37. In the embodiment shown, a portion of the signal conductor array 40 is positioned on the wall 38 of the carrier element 36 which, in the position according to the application, lies against the inner side of the teeth of the dental arch 31. The sensitivity of the signal conductor array 40 along the inner side of the teeth of the dental arch 31 is thereby increased. It is conceivable that the wall 38 of the carrier element 36 which is positioned on the outer side of the teeth also has a signal conductor array 40, so that the dental arch 31 of the patient 15 is surrounded with signal conductors 37 along the inner side of the teeth, the occlusal surface and the outer side of the teeth.

[0110] Figure 7 One alternative embodiment of the antenna array 26 shown in Figure 6 surrounds a quarter of the dental arch 31 of the patient 15. The signal conductor array 40 is inserted into the recess 39 of the carrier element 36, similar to the embodiment in Figure 6 , and is positioned on the occlusal surface and on the inner side of the dental arch 31 of the patient 15 in the position according to the application of the carrier element 36.

[0111] Figure 4 to Figure 7 The embodiments shown in

[0112] Figure 8 A schematic cross section through a portion of the carrier element 36 of the antenna array 26 with a holding device 51 is shown. The cross section shows the recess 39 of the carrier element 36 which accommodates the tooth 41 of the patient 15. The carrier element 36 of the antenna array 26 is guided for this purpose along a connection direction 53 onto the tooth 41, wherein the signal conductor array 40 is deflected in the direction of the recess 39 and is shaped over the tooth 41. The signal conductor array 40 is supported here by means of the elastic element 52 of the holding device 51. In the example shown, the elastic element 52 is a spring which, in the position according to the application, tensions the signal conductor array 40 over the tooth 41. Instead of the signal conductors 37, the antenna array 26 can also have a single signal conductor 37. In the embodiment, the signal conductor 37 or the signal conductor array 40 is at least deformable or flexible, so that it can be fitted without damage to the surface profile of the tooth 41. For this purpose, asFigure 8 The diagram shows that the signal conductor array 40 can have flexible and / or movable elements relative to each other.

[0113] Figure 9 Show Figure 8 In one embodiment, the carrier element 36 is positioned on the dental arch 31 of the patient 15 according to the location of the application. Figure 8 Compared to the illustration, the elastic element 52 elastically deflects and tensions the signal conductor array 40 over the tooth 41. The tooth 41 is thus surrounded by the signal conductor array 40 along its free surface. Consequently, the signal conductor array 40 is positioned on the inner, occlusal, and outer surfaces of the tooth 41. In the illustrated embodiment, a portion of the carrier element 36 protrudes beyond the gingiva 42 of the patient 15. The signal conductor array 40 preferably has a cladding and / or shielding (not shown) providing thermal and electrical insulation between the signal conductor 37 and the tooth 41.

[0114] Figure 10 An embodiment of an antenna array 26 with a retaining device 51 is shown, which is positioned on the dental arch 31 of the patient 15 in the mandible, depending on the application. In the illustrated embodiment, multiple arrays of signal conductors 37 are respectively connected to the retaining device 51 on both sides of the dental arch 31. The multiple arrays of signal conductors 37 may be positioned side-by-side or partially overlapping. It is conceivable that a signal conductor array 40 is provided for each tooth 41. However, the signal conductor array 40 may also surround any portion of the dental arch 31, such as multiple teeth.

[0115] Figure 11One embodiment of an antenna array 26 with electrically conductive shields 54 is shown. In the example shown, the carrier element 36 is implemented in one piece and has a surrounding recess 39 for accommodating the dental arches 31 of the upper and lower jaw, respectively. The electrically conductive shields 54 are positioned between the cheeks 62 of the patient 15 and the tooth outer sides and shield the antenna array 26 from radio frequency signals from the direction of the cheeks 62. In the example shown, two electrically conductive shields 54 are positioned on both cheeks of the patient 15. It is conceivable that the antenna array 26 also has electrically conductive shields 54 between the tooth inner sides and the tongue 61 of the patient 15. The electrically conductive shields can be connected with the carrier element 36 or separate from the carrier element 36, for example. Preferably, the electrically conductive shields 54 for shielding the tongue 61 from magnetic resonance signals are constructed circumferentially on the tooth inner sides of the dental arches 31. In the embodiment shown, the carrier element 36 also has spacing holders 55 which establish a predetermined spacing between the two dental arches 31 in the position of the carrier element 36 according to the application. The spacing is dimensioned such that the jaw muscles of the patient 15 are stretched and exert a resetting force on the carrier element 36 which presses the dental arches 31 into the recesses 39 of the carrier element 36 against the elastic pulling force of the elastic elements 52.

[0116] The embodiment shown also has an array of signal conductors 37 which are positioned arcuately on the palate 63 and the hyoid bone 64 of the patient 15. The array of signal conductors 37 is connected here with the arcuate structure on the palate and on the hyoid bone of the carrier element 36. It is conceivable that the side of the carrier element 36 facing the tongue 61 also has electrically conductive shields 54 along the palate 63 and the hyoid bone 64 in order to shield the array of signal conductors 37 on the palate 63 and on the hyoid bone 64 from radio frequency signals of the movable tongue 61.

[0117] Figure 12 A possible flow chart of a method according to the application for performing a magnetic resonance measurement on the full set of teeth 30 of a patient 15 is shown. The step of positioning the antenna array 26 on the full set of teeth 30 of the patient 15 in the position according to the application can be carried out automatically or in a remote-controlled manner with a corresponding device, for example.

[0118] In step S1 of the method according to the application, the carrier element 36 is oriented with respect to the full complement of teeth 30 of the patient 15 using the antenna array 26, wherein the side of the carrier element 36 which imitates the full complement of teeth 30 is oriented in the direction of the full complement of teeth 30 of the patient 15. The orientation of the carrier element 36 is here carried out outside the mouth of the patient 15. The orientation of the carrier element 36 can be determined on the basis of the shape of the carrier element 36, which imitates the full complement of teeth 30 of the patient 15. For example, the plane defined by the recesses 39 is oriented with a small angle with respect to the plane of the occlusal surface of the dental arch 31 of the patient 15, or the plane of the occlusal surface of the dental arch 31 of the patient 15 is oriented with respect to the plane defined by the recesses 39. The orientation of the antenna array can be carried out, for example, in a camera-supported manner, in that the image data of one or more cameras are used to calculate the orientation of the carrier element 36 with respect to the full complement of teeth 30 of the patient 15.

[0119] In a further step S2 of the method according to the application, the carrier element 36 is connected with the full complement of teeth 30 of the patient 15 in the position according to the application by the side imitating the full complement of teeth 30 being brought into contact with the full complement of teeth 30. The carrier element 36 forms a form-fitting connection with the full complement of teeth 30 in the position according to the application, such that relative movements of the antenna array 26 with respect to the full complement of teeth 30 of the patient 15 during the magnetic resonance examination are avoided. By positioning the carrier element 36 in the position according to the application, the freedom of movement of the tongue and / or the jaw of the patient 15 is restricted in order to reduce image artifacts caused by movements of the patient 15.

[0120] In an embodiment of the method according to the application, the carrier element 36 has plastic blocks 34 in the recesses 39 of the dental arch 31 of the patient 15, which mold the dental arch 31 of the patient 15 when the carrier element 36 is connected with the full complement of teeth 30. Here, the plastic blocks 34 form a form-fitting connection with the dental arch 31 and reversibly fasten the antenna array 26 on the full complement of teeth 30 of the patient 15. The distribution of the plastic blocks 34 on the dental arch 31 can be supported here by the circumferential walls 38 on the inner and / or outer side, which press the plastic blocks onto the free surfaces of the teeth 41, such that the interdental spaces are also filled with the plastic blocks 34.

[0121] According to a further embodiment of the method according to the application, the signal conductor array 40 of the antenna array 26 is supported above the recess 39 of the carrier element 36 by means of the holding device 51 and is deflected from at least one portion of the dental arch 31 in the direction of the carrier element 36 towards the recess 39 when the carrier element 36 is connected with the full set of teeth 30. The dental arch 31 is guided here in the connection direction 53 into the recess 39 of the carrier element 36 in order to establish the position of the antenna array 26 according to the application at the full set of teeth 30 of the patient 15. By means of the resilient element 52 of the holding device 51, the signal conductor array 40 is tensioned by the dental arch 31 of the patient 15 over the free surface of the dental arch 31 when deflected, so that the inner sides of the teeth, the biting surface and the outer sides of the teeth of the dental arch are surrounded by the signal conductor array 40.

[0122] In step S3 of the method according to the application, a magnetic resonance measurement is carried out on the full set of teeth 30 of the patient 15, wherein the antenna array 26 detects radio frequency signals by means of the at least one signal conductor 37 and transmits the radio frequency signals to a receiver of the magnetic resonance device. The transmission of the radio frequency signals can take place wired or wirelessly as described above. In the wired embodiment, the antenna array is connected via the electrical connection line 27 with the radio frequency unit 21, which is the receiver of the magnetic resonance device.

[0123] The imaging sequence serves to carry out the magnetic resonance measurement, which allows a good differentiation of the full set of teeth 30 from the surrounding tissue. Here, as described above, imaging sequences with very short echo times or very long echo times can be used, which show the dentin and the tooth enamel of the patient 15 in the image data in terms of signal strength or without signal.

[0124] In a possible embodiment of the method according to the application, the radio frequency signals of the signal conductor array 40 are detected with a plurality of receiving channels, which enables the use of parallel imaging methods. Here, a reduction of the measurement duration of the magnetic resonance measurement is achieved by recording a reduced number of k-space data, in particular by reducing the number of phase encoding steps. The k-space data are then reconstructed by the evaluation unit 28 of the magnetic resonance device 10 using a reconstruction method in order to generate image data of the full set of teeth 30 of the patient 15.

[0125] In an optional step S4 of the method according to the application, the carrier element 36 with the plastic block 34 is detached from the full dentition of the patient 15 and serves for creating a positive model of the full dentition 30. To this end, as described above, the plastic block 34 with the impression of the full dentition 30 of the patient 15 is filled with molding material. After the molding material has hardened, the carrier element 36 is detached from the molding material in order to obtain a positive model of the full dentition 30 of the patient 15. The positive model can be used, for example, as a model for creating a denture for the patient 15. However, it is equally conceivable that the positive model is used for exclusively creating an adapted antenna array 26 for further magnetic resonance examinations.

[0126] Of course, the order of the above-described method steps is not fixed. Individual steps, for example the creation of a positive model of the full dentition 30 of the patient 15, can also be performed in a different order than described herein.

[0127] Although the details of the application have been illustrated and described by means of preferred embodiments, the application is not restricted to the disclosed examples and can be varied in many ways by a person skilled in the art without departing from the scope of the application.

Claims

1. An antenna array (26) for receiving radio frequency signals in a frequency range and a power range of a magnetic resonance device (10), the antenna array (26) comprising: at least one signal conductor (37) which constitutes a radio frequency signal for receiving an alternating magnetic field and transmitting the radio frequency signal to the magnetic resonance device (10), and a carrier element (36) which is mechanically connected to the signal conductor (37), characterized in that the carrier element (36) contours at least a portion of the full complement of teeth (30) of an examination object (15), wherein the carrier element (36) can be connected in a form-fitting manner to the full complement of teeth (30) of the examination object in a position according to the application in order to position the signal conductor (37) on the full complement of teeth (30) of the examination object (15), wherein the antenna array (26) has a signal conductor array (40), wherein the signal conductor array (40) contours at least a portion of a dental arch (31), wherein at least a portion of the signal conductor array (40) is oriented in an orientation perpendicular to the plane of the occlusal surface on the inner and / or outer side of the teeth of the dental arch (31), wherein the carrier element (36) has a recess (39) for accommodating the dental arch (31) and a holding device (51) for fastening the signal conductor (37) or the signal conductor array (40), wherein the signal conductor or the signal conductor array is fastened on the holding device with a resilient element, and wherein the signal conductor array is positioned such that the signal conductor or the signal conductor array surrounds the dental arch of the examination object along the free surface of the teeth from the inner side of the teeth via the occlusal surface to the outer side of the teeth.

2. Antenna array (26) according to claim 1, wherein the antenna array (26) constitutes a radio frequency signal in the frequency range and power range of the magnetic resonance device (10) for emitting into the examination object (15).

3. Antenna array (26) according to claim 1 or 2, wherein the signal conductor (37) is embedded in the material of the carrier element (36).

4. Antenna array (26) according to claim 1 or 2, wherein the signal conductor (37) has a loop which contours at least a portion of the dental arch (31) of the examination object (15).

5. Antenna array (26) according to claim 1, wherein at least a portion of the signal conductor array (40) is oriented along the plane of the occlusal surface of the examination object (15).

6. Antenna array (26) according to claim 1 or 2, wherein the carrier element (36) surrounds the dental arch (31) of the examination object (15) at least along the tooth side on which the signal conductor (37) or the signal conductor array (40) is positioned in a position according to the application, wherein the signal conductor (37) or the signal conductor array (40) is positioned on a side of the carrier element (36) which, in a position according to the application, faces the dental arch (31).

7. Antenna array (26) according to claim 1 or 2, wherein the carrier element (36) has a plastic block (34) on the side facing the dental arch (31) in the position according to the application, which plastic block (34) can be deformed upon contact with the full set of teeth (30) of the examination object (15).

8. Antenna array (26) according to claim 6, wherein the signal conductor (37) or the signal conductor array (40) is supported above the recess (39) by means of the holding device (51) and can be molded onto the full set of teeth (30) of the examination object (15) by positioning the carrier element (36) according to the application on the full set of teeth (30) of the examination object (15).

9. Antenna array (26) according to claim 1 or 2, wherein at least a part of the antenna array (26) is designed to be positioned along a part of the palate (63) and / or the hyoid bone (64) of the examination object (15) in the position according to the application.

10. Antenna array (26) according to claim 1 or 2, wherein the antenna array (26) has at least one electrically conductive shield (54), which is positioned between the antenna array (26) and the soft tissue of the examination object (15) in the position according to the application of the antenna array (26) and constitutes a radio frequency signal for shielding from the direction of the alternating magnetic field from soft tissue.

11. System comprising a magnetic resonance device (10) and an antenna array (26) according to claim 1, wherein the magnetic resonance device (10) has a signal connection to the antenna array (26) and constitutes a radio frequency signal for receiving the antenna array (26) and creating image data of the full set of teeth (30) of the examination object (15).

12. System according to claim 11, wherein the magnetic resonance device (10) comprises a plurality of receiving channels, which have a plurality of signal connections to the signal conductor array (40).

13. Method for performing a magnetic resonance measurement on a full set of teeth (30) of an examination object (15) with an antenna array (26) according to claim 1, wherein the antenna array (26) is connected to the full set of teeth (30) of the examination object (15) in a predetermined relative position, the method having the following steps: - orienting (SI) a carrier element (36) with the antenna array (26) relative to the full set of teeth (30) in the mouth of the examination object (15), wherein the side of the carrier element (36) which is shaped to the full set of teeth (30) is oriented in the direction towards the full set of teeth (30) of the examination object (15), - connecting (S2) the carrier element (36) to the full set of teeth (30) of the examination object (15) in the position according to the application by means of bringing the side of the carrier element (36) which is shaped to the full set of teeth (30) of the examination object (15) into contact with the full set of teeth (30). - performing (S3) a magnetic resonance measurement of the full dentition (30) of the examination object (15), wherein the antenna array (26) detects radio frequency signals by means of the at least one signal conductor (37) and transmits the radio frequency signals to a receiver of the magnetic resonance device (10).

14. The method according to claim 13, using the system according to claim 11 and the antenna array (26) according to claim 7, wherein the plastic block (34) of the carrier element (36) is deformed upon connection (S2) with the full dentition (30) and constitutes a form-fit connection with the full dentition (30) of the examination object (15), which reversibly fastens the carrier element (36) on the full dentition (30).

15. The method according to claim 14, further having the following step: - detaching the carrier element (36) from the full dentition (30) of the examination object (15) and creating a positive mold of the full dentition (30) of the examination object (15) based on the plastic block (34) of the carrier element (36).

16. The method according to claim 13, using the system according to claim 11 and the antenna array (26) according to claim 8, wherein the signal conductor (37) or signal conductor array (40) is supported above the recess (39) of the carrier element (36) by means of a holding device (51) and, upon connection (S2) of the carrier element (36) with the full dentition (30), is deflected from at least a portion of the dental arch (31) in a direction of the carrier element (36) towards the recess (39), wherein at least a portion of the dental arch (31) is surrounded by the signal conductor (37) or signal conductor array (40) along a free surface.

17. The method according to claim 13, using the system according to claim 12, wherein the magnetic resonance measurement is performed (S3) in one step using a plurality of receiving channels, which receive magnetic resonance signals from the signal conductor array (40), wherein, in order to reduce a measurement duration of the magnetic resonance measurement, a reduced number of K-space data is detected and a parallel imaging method is used in order to reconstruct image data of the full dentition (30) from the reduced number of K-space data.

Images