MAGNETIC RESONANCE ELASTOGRAPHY DEVICE

Description

[0001] The present invention relates to a magnetic resonance elastography device comprising a magnetic resonance device and an elastography device.

[0002] Tumor tissue and healthy tissue, especially tumor-free tissue, exhibit different vibration properties and / or different excitation behavior when subjected to vibration. Diagnostic imaging, particularly elastography, utilizes these differing vibration properties and / or excitation behaviors between different tissue types, especially healthy tissue and tumor tissue. This differing behavior can be visualized in a magnetic resonance elastogram using magnetic resonance imaging (MRI) and used for diagnosis.

[0003] During magnetic resonance elastography examinations, the generation of a drive torque for the elastography device can lead to undesirable disturbances and / or interference with a high-frequency antenna unit of the magnetic resonance device.

[0004] Wolfgang Loew et al.: "A Dedicated 3 Tesla Prostate Coil for Magnetic Resonance Elastography, Imaging, and Tracking", Proceedings of the International Society for Magnetic Resonance in Medicine, ISMRM, Joint Annual Meeting ISMRM-ESMRMB, Milan, Italy, 10-16 May 2014, No. 2180, 25 April 2014 (2014-04-25), XP040663249, discloses a system with a magnetic resonance device and an elastography device, in which parts of the elastography device are arranged in an RF-shielded Faraday cage.

[0005] From JP 2002 010991 A a device is known which comprises a vibration-generating device (elastography device) and a magnetic resonance device.

[0006] Another magnetic resonance device with an elastography device is described, for example, in Qite Chen et al.: "The Design of Shear Wave Drive Device in Magnetic Resonance Elastography", Bioinformatics and Biomedical Engineering, (ICBBE) 2011 5th International Conference, IEEE, May 10, 2011 (2011-05-10), pages 1-4, XP031878910, DOI: 10.1109 / ICBBE.2011.5780456, ISBN: 978-1-4244-5088-6.

[0007] US patent 2015 / 148663A1 discloses an oscillation applicator for MR rheology. The oscillation applicator comprises a transducer that generates a back-and-forth motion at a specific frequency and a strap mechanically coupled to the transducer, which can be wrapped around a patient's body.

[0008] The present invention is based in particular on the objective of providing an elastography device that can be operated without interference together with a magnetic resonance device. This objective is achieved by the features of the independent claim. Advantageous embodiments are described in the dependent claims.

[0009] The invention relates to a magnetic resonance elastography device comprising a magnetic resonance device and an elastography device, wherein the magnetic resonance device comprises: a scanner unit, a patient reception area at least partially surrounded by the scanner unit, and a patient table designed for the insertion of a patient into the patient reception area, the elastography device includes: a drive unit, a vibration applicator positioned on the patient for magnetic resonance elastography examination, and a force transmission unit designed to transmit a drive torque from the drive unit to the vibration applicator.

[0010] Furthermore, the elastography device comprises an EMC-tight shielded housing with a cylindrical high-frequency waveguide (HF waveguide), wherein the drive unit is arranged inside the high-frequency waveguide. According to the invention, the high-frequency waveguide comprises a length and a diameter, wherein the ratio of the length to the diameter is tuned to a vibration spectrum generated by the drive unit in such a way as to achieve attenuation of electromagnetic waves and thus also prevent unwanted interaction between the elastography device and the magnetic resonance device.

[0011] The magnetic resonance device preferably comprises a medical and / or diagnostic magnetic resonance device designed and / or configured for acquiring medical and / or diagnostic image data, in particular medical and / or diagnostic magnetic resonance image data, of a patient. The scanner unit of the magnetic resonance device preferably comprises a detector unit, in particular a magnet unit, for acquiring the medical and / or diagnostic image data, in particular magnetic resonance image data. The scanner unit, in particular the magnet unit, comprises a base magnet, a gradient coil unit, and a radio frequency antenna unit. The radio frequency antenna unit is fixedly arranged within the scanner unit. Furthermore, the magnetic resonance device may also include local radio frequency coils arranged around the area of ​​the patient being examined for acquiring magnetic resonance data.

[0012] The base magnet is designed to generate a homogeneous base magnetic field with a defined magnetic field strength, such as 0.55 T, 1.5 T, 3 T, 7 T, etc. In particular, the base magnet is designed to generate a strong, constant, and homogeneous base magnetic field. The homogeneous base magnetic field is preferably located and / or present within a patient acquisition area of ​​the magnetic resonance imaging (MRI) device. The gradient coil unit is designed to generate magnetic field gradients used for spatial encoding during imaging.

[0013] For a magnetic resonance imaging (MRI) scan, the patient, and in particular the area of ​​the patient to be examined, is positioned within a patient acquisition area of ​​the MRI scanner. The patient acquisition area is at least partially surrounded by the scanner unit, preferably in a cylindrical shape. A field of view (FOV) and / or an isocenter of the MRI scanner is preferably arranged and / or located within the patient acquisition area. The FOV preferably comprises a detection area of ​​the MRI scanner within which the conditions for acquiring medical image data, in particular MRI image data, are present, such as a homogeneous background magnetic field.The isocenter of the magnetic resonance device preferably comprises the region and / or point within the magnetic resonance device that exhibits the optimal and / or ideal conditions for acquiring medical image data, in particular magnetic resonance image data. In particular, the isocenter comprises the most homogeneous magnetic field region within the magnetic resonance device.

[0014] For positioning the patient, and in particular the area of ​​the patient to be examined, within the patient acquisition area, the magnetic resonance imaging (MRI) device has a patient table that is movable within this area. For an MRI scan, the patient is first positioned on the patient table of the patient positioning device, and then the patient table, along with the patient, is moved into the patient acquisition area until the area of ​​the patient to be examined is positioned within the isocenter.

[0015] The drive unit of the elastography device is designed to generate a drive torque, which is preferably transmitted to the vibration applicator. For this purpose, the drive unit can include a motor unit, for example, a stepper motor. The drive unit can also include a motor control unit.

[0016] The vibration applicator of the elastography device is specifically designed to generate vibrations and / or pressure waves and to transmit these vibrations and / or pressure waves to and / or onto the patient. Preferably, the vibration applicator is positioned close to the patient, particularly near the area of ​​the patient being examined. For example, the vibration applicator is placed against the area of ​​the patient being examined. During a magnetic resonance elastography examination, the vibration applicator is therefore located within the patient's field of view, specifically within the field of view.

[0017] The power transmission unit comprises a power transmission element, preferably designed to be magnetic resonance compatible, so that no interference is caused by the power transmission unit during magnetic resonance elastography examinations. The power transmission element can include a magnetic resonance compatible shaft, in particular a flexible shaft, thus enabling simple and flexible arrangement of the vibration applicator relative to the drive unit.

[0018] The EMC (electromagnetic compatibility)-tight shielding housing prevents unwanted interaction between the drive unit and the scanner unit, particularly the high-frequency antenna unit of the scanner unit of the magnetic resonance device. An EMC-tight shielding housing has the property of shielding unwanted electrical or electromagnetic effects. In particular, such electrical or electromagnetic effects of the drive unit of the elastography device can be advantageously shielded. Preferably, the cylindrical RF waveguide has a circular and / or round cross-section. It is particularly advantageous for the RF waveguide to be rotationally symmetrical with respect to a longitudinal axis, which preferably runs through the center of the RF waveguide.

[0019] The invention offers the advantage that the elastography device can be operated interference-free with the magnetic resonance device for magnetic resonance elastography examinations. This also enables simple integration of the elastography device with a magnetic resonance device. Furthermore, the drive unit can be positioned at any location in the vicinity of the magnetic resonance device thanks to the EMC-shielded housing. This embodiment of the invention also offers the advantage that a simple geometric design of the RF waveguide provides advantageous filtering and / or shielding. In particular, the RF waveguide can achieve advantageous attenuation of electromagnetic waves, thereby preventing unwanted interaction between the elastography device, especially the drive unit of the elastography device, and the magnetic resonance device.

[0020] In an advantageous embodiment of the magnetic resonance elastography device according to the invention, the drive unit may include a motor control unit, the motor control unit being arranged within the EMC-shielded housing. The motor control unit is preferably configured to control the motor, for example, a stepper motor, of the elastography device. Furthermore, the motor control unit may also be coupled to the magnetic resonance device to enable data exchange between the magnetic resonance device and the elastography device, for example, during a magnetic resonance elastography examination. This embodiment of the invention has the advantage of allowing a particularly compact arrangement of the entire drive unit within the EMC-shielded housing.

[0021] In an advantageous embodiment of the magnetic resonance elastography device according to the invention, the drive unit, together with the EMC-shielded housing, can be arranged outside the patient acquisition area. In particular, the drive unit, together with the EMC-shielded housing, is arranged outside the patient acquisition area during a magnetic resonance elastography examination. The drive unit, together with the EMC-shielded housing, can, for example, be arranged and / or positioned at one end of the patient table. Furthermore, the drive unit, together with the EMC-shielded housing, can also be arranged and / or positioned next to the patient table during patient preparation and / or the magnetic resonance elastography examination, and remain there during the magnetic resonance elastography examination.This embodiment of the invention has the advantage that sufficient space is available for the patient within the patient admission area during a magnetic resonance elastography examination.

[0022] According to the invention, the high-frequency waveguide comprises a length and a diameter, wherein a ratio of the length to the diameter is tuned to a vibration spectrum generated by the drive unit in such a way as to achieve damping of electromagnetic waves and thus also prevent an unwanted interaction between the elastography device and the magnetic resonance device.

[0023] In an advantageous embodiment of the magnetic resonance elastography device according to the invention, the high-frequency waveguide may comprise a non-magnetic, metallic tube, thereby achieving advantageous shielding against electromagnetic interference. Preferably, the RF waveguide comprises an aluminum tube.

[0024] In an advantageous embodiment of the magnetic resonance elastography device according to the invention, the high-frequency waveguide may have two end regions arranged on opposite sides along its length, with at least one end region being open. This allows for a structurally simple shielding of the drive unit. Furthermore, the open design of the RF waveguide makes it particularly easy to route a power transmission element, for example, a drive shaft, from the power transmission unit to the outside. If the RF waveguide is open at both ends, the drive unit should be positioned in the center of the RF waveguide to achieve effective attenuation and / or shielding.The drive unit should be positioned within the RF waveguide at an equal distance from both end sections. If, however, the RF waveguide is open at only one end section, its length can be halved compared to a design open at both ends to achieve the same attenuation and / or shielding performance, provided the drive unit is located within the closed end section of the RF waveguide. The RF waveguide may include a cover that seals the closed end section. This cover must be securely attached to the end section of the RF waveguide, for example, by welding, riveting, or other fastening methods deemed appropriate by a person skilled in the art.

[0025] In an advantageous embodiment of the magnetic resonance elastography device according to the invention, the elastography device may include a signal transmission unit for transmitting signals to the drive unit arranged within the RF waveguide, wherein the signal transmission unit comprises at least one optical fiber cable. The signal transmission unit can advantageously provide signals, in particular data signals, for example control signals, and / or a power supply, for the drive unit and / or for powering the drive unit within the RF waveguide. Preferably, the signal transmission unit is designed such that a filter effect and / or attenuation effect generated by the RF waveguide is not impaired by the signal lines of the signal transmission unit but is maintained.The optical fiber cable can, for example, comprise a glass fiber cable and / or polymer optical waveguides, etc. The use of optical fiber cables has the advantage that electrically invisible cables can be used for signal transmission and / or data transmission. Furthermore, this prevents metallic cable components from being inserted into the EMC-tight shielded housing, especially into the RF waveguide, where they could, for example, act as an antenna.

[0026] In an advantageous embodiment of the magnetic resonance elastography device according to the invention, the signal transmission unit may comprise at least one pass-through filter and / or feed-through filter. The pass-through filter can advantageously provide power to the drive unit and / or other units arranged within the EMC-tight shielded housing, particularly within the RF waveguide. Preferably, the at least one pass-through filter is arranged within the RF waveguide with contact to the RF waveguide, for example, via a common contact surface.

[0027] Further advantages, features and details of the invention will become apparent from the exemplary embodiments described below and from the drawings.

[0028] They show: Fig. 1 a magnetic resonance elastography device according to the invention with a magnetic resonance device and an elastography device in a schematic representation, and Fig. 2 a first embodiment of an RF waveguide of the elastography device, and Fig. 3 a second embodiment of an RF waveguide of the elastography device.

[0029] In Fig. 1 Figure 10 schematically depicts a magnetic resonance elastography device. The magnetic resonance elastography device 10 comprises a magnetic resonance device 11 and an elastography device 30.

[0030] The magnetic resonance imaging (MRI) device 11 comprises a scanner unit 12 formed by a magnetic unit. The MRI device 11 also has a patient acquisition area 13 for scanning a patient 14. In the present embodiment, the patient acquisition area 13 is cylindrical and is surrounded in a cylindrical shape in one circumferential direction by the scanner unit 12, in particular by the magnetic unit. However, a different configuration of the patient acquisition area 13 is conceivable. The patient 14 can be moved and / or advanced into the patient acquisition area 13 by means of a patient positioning device 15 of the MRI device 11. For this purpose, the patient positioning device 15 includes a patient table 16 that is movable within the patient acquisition area 13.In particular, the patient table 16 is mounted in a way that allows movement in the direction of a longitudinal extension of the patient reception area 13 and / or in the z-direction.

[0031] The scanner unit 12, in particular the magnet unit, comprises a superconducting base magnet 17 for generating a strong and, in particular, constant base magnetic field 18. Furthermore, the scanner unit 12, in particular the magnet unit, includes a gradient coil unit 19 for generating magnetic field gradients, which are used for spatial encoding during imaging. The gradient coil unit 19 is controlled by a gradient control unit 20 of the magnetic resonance device 11. The scanner unit 12, in particular the magnet unit, further comprises a high-frequency antenna unit 21 for exciting a polarization that is established in the base magnetic field 18 generated by the base magnet 17.The high-frequency antenna unit 21 is controlled by a high-frequency antenna control unit 22 of the magnetic resonance device 11 and transmits high-frequency magnetic resonance sequences into the patient acquisition area 13 of the magnetic resonance device 11.

[0032] The magnetic resonance device 11 includes a system control unit 23 for controlling the base magnet 17, the gradient control unit 19, and the high-frequency antenna control unit 21. The system control unit 23 centrally controls the magnetic resonance device 11, for example, by performing a predetermined imaging gradient echo sequence. The system control unit 23 also includes an evaluation unit (not shown) for evaluating medical image data acquired during the magnetic resonance examination.

[0033] Furthermore, the magnetic resonance device 11 includes a user interface 24, which is connected to the system control unit 23. Control information, such as imaging parameters, as well as reconstructed magnetic resonance images, can be displayed and / or output to a medical operator on an output unit 25, for example, on at least one monitor. The user interface 24 also includes an input unit 26, by means of which information and / or parameters can be entered by the medical operator during a measurement procedure.

[0034] The elastography device 30 comprises a vibration applicator 31, which includes a vibration generator unit. The vibration applicator 31 is positioned directly on the patient 14, in particular on the area of ​​the patient 14 to be examined, during a magnetic resonance elastography examination.

[0035] Furthermore, the elastography device 30 includes a drive unit 32. The drive unit 32 is designed and / or configured to generate a drive torque for the vibration generator unit during an elastography examination. To prevent interference and / or undesired interactions between the drive unit 32 and the scanner unit 12, in particular the high-frequency antenna unit 21, the elastography device 30 also includes an EMC-shielded housing 33 in which the drive unit 32 is located. During a magnetic resonance elastography examination, the drive unit 32, together with the EMC-shielded housing 33, is located outside the patient acquisition area 13 of the magnetic resonance device 11.

[0036] To transmit a drive torque from the drive unit 32 to the vibration applicator 31, the elastography device 30 has a force transmission unit 34. The force transmission unit 34 has at least one force transmission element 35, which is preferably designed as a flexible and magnetic resonance-compatible shaft.

[0037] In Fig. 2 A first embodiment of the elastography device 30, in particular the drive unit 32 and the EMC-tight shielded housing 33 of the elastography device 30, is shown in more detail. The drive unit 32 comprises a motor unit 36, which is designed, for example, as a stepper motor, and a motor control unit 37. Both the motor unit 36 ​​and the motor control unit 37 are arranged within the EMC-tight shielded housing 33.

[0038] The EMC-tight shielded housing 33 comprises a cylindrical high-frequency waveguide (HF waveguide 38). The HF waveguide 38 comprises a non-magnetic tube. Preferably, the HF waveguide 38, and in particular the tube, has a round and / or circular cross-section. The HF waveguide 38 also comprises a metallic tube, such as an aluminum tube.

[0039] In order to achieve advantageous shielding and / or damping, the RF waveguide 38 has a diameter 39 and a length 40, wherein a ratio of the length 40 to the diameter 39 of the RF waveguide 38 is matched to a vibration spectrum generated by the drive unit 32.

[0040] The RF waveguide 38 also has two end regions 41, 42, which are arranged longitudinally along the RF waveguide 38 at opposite sides and / or ends. In the present embodiment, both end regions 41, 42 of the RF waveguide 38 are open. In this embodiment, the drive unit 32 is preferably arranged in the center of the RF waveguide 38, particularly longitudinally along the RF waveguide 38, so that there is as equal a distance as possible to both end regions 41, 42 of the RF waveguide 38 in order to ensure effective attenuation and / or shielding of electromagnetic waves. The power transmission element 35, in particular the drive shaft, is guided outwards from the RF waveguide 38 through a first end region 41 of the two end regions 41, 42.

[0041] The elastography device 30 further comprises a signal transmission unit 43 for transmitting signals to the drive unit 32, in particular the motor unit 36 ​​and the motor control unit 37, which is arranged within the RF waveguide 38. The signal transmission unit 43 can advantageously provide signals, in particular data signals, for example control signals, and / or a power supply, to the drive unit 32 and / or to power the drive unit 32. The signal transmission unit 43 includes at least one optical fiber cable 44. The at least one optical fiber cable 44 can, for example, comprise a fiber optic cable and / or polymer optical waveguides, etc. The at least one optical fiber cable 44 is designed for data transmission and / or a power supply.The signal transmission unit 43 can also have more than one optical fiber cable 44 for data transmission and / or for supplying power to the drive unit 32. For example, two optical fiber cables 44 can be available for supplying power to the drive unit 32.

[0042] Furthermore, the signal transmission unit 43 has at least one pass-through filter 45 and / or a feed-through filter for a power supply, in particular a power supply for the drive unit 32, especially the motor unit 36. The pass-through filter 45 and / or the feed-through filter is arranged within the RF waveguide 38 in contact with it. In the present embodiment, the pass-through filter 45 and / or the feed-through filter has a contact surface with the RF waveguide 38.

[0043] In Fig. 3 Figure 1 shows an alternative embodiment of the elastography device 100, in particular of an RF waveguide 101 of the elastography device 100. Essentially identical components, features, and functions are generally numbered with the same reference numerals. The following description is essentially limited to the differences from the embodiment in Figure 1. Fig. 1 and 2 , whereby with regard to unchanged components, features and functions, reference is made to the description of the exemplary embodiment in the Fig. 1 and 2 is referred.

[0044] The elastography device 100 in Fig. 3 differs from the elastography device 100 in Fig. 2 in a training of the RF waveguide 101. A further embodiment of the elastography device 100 corresponds to the to Fig. 2 The presented and described explanations.

[0045] The elastography device 100 also includes an RF waveguide 101, within which the drive unit 32 is arranged. The RF waveguide 101 has two end sections 102, 103, which are arranged longitudinally along the RF waveguide 101 at opposite sides and / or ends. In the present embodiment, only one end section 102 of the two end sections 102, 103 of the RF waveguide 101 is open. Through the open end section 102, the force transmission element 35, in particular the shaft, is guided outwards from the RF waveguide 101. The other end section 103 of the two end sections 102, 103, on the other hand, is closed.The closed end region 103 has a cover 104 which is firmly connected to the end region 103 of the RF waveguide 101, for example by welding and / or riveting to the end region 103 and / or by other fastening methods that appear sensible to a person skilled in the art.

[0046] In such a configuration of the RF waveguide 101, the drive unit 32, in particular the motor unit 36 ​​and the motor control unit 37, can be arranged in this closed end region 103 of the RF waveguide 101. This also makes it possible for the RF waveguide 101 to have the length required for shielding and / or attenuation of electromagnetic waves in only one direction.

[0047] The further design of the RF waveguide 101 and also of the signal transmission unit 43 for transmitting signals and / or data into the RF waveguide 101 corresponds to the explanations regarding Fig. 2 , to which reference is hereby made.

[0048] The in the Fig. 1 bis 3 The magnetic resonance elastography devices 10 shown may, of course, include further components that magnetic resonance elastography devices 10 typically possess. Furthermore, the general operating principle of a magnetic resonance elastography device 10 is known to those skilled in the art, so a detailed description of the further components is omitted.

[0049] Although the invention has been illustrated and described in detail by the preferred embodiment, the invention is not limited by the disclosed examples and other variations can be derived by the person skilled in the art without leaving the scope of protection of the invention.

Claims

1. Magnetic resonance elastography apparatus (10) with a magnetic resonance apparatus (11) and an elastography apparatus (30, 100), wherein the magnetic resonance apparatus (11) comprises: - a scanner unit (12), - a patient receiving region (13) surrounded at least partially by the scanner unit (12), and - a patient couch (16), which is embodied to introduce a patient (14) into the patient receiving region (13), wherein the elastography apparatus (30, 100) comprises: - a drive unit (32), - a vibration applicator (31), which is arranged on the patient (14) for a magnetic resonance elastography examination, and - a force transmission unit (34), which is embodied to transmit a drive moment from the drive unit (32) to the vibration applicator (31), wherein the elastography apparatus comprises an EMC-tight shield housing (33) with a cylindrical radiofrequency hollow conductor (38, 101), wherein the drive unit (32) is arranged within the radiofrequency hollow conductor (38, 101), wherein the radiofrequency hollow conductor (38, 101) comprises a length (40) and a diameter (39), characterised in that a ratio of the length (40) to the diameter (39) is matched to an oscillation spectrum produced by the drive unit (32) so that an attenuation of electromagnetic waves is achieved and an unwanted interaction between the elastography apparatus and the magnetic resonance apparatus is also prevented.

2. Magnetic resonance elastography apparatus (10) according to claim 1, characterised in that the drive unit (32) has a motor control unit (37), wherein the motor control unit (37) is arranged within the EMC-tight shield housing (33).

3. Magnetic resonance elastography apparatus (10) according to one of the preceding claims, characterised in that the drive unit (32) together with the EMC-tight shield housing (33) is arranged outside of the patient receiving region (13).

4. Magnetic resonance elastography apparatus (10) according to one of the preceding claims, characterised in that the radiofrequency hollow conductor (38, 101) comprises a non-magnetic, metallic tube.

5. Magnetic resonance elastography apparatus (10) according to one of the preceding claims, characterised in that the radiofrequency hollow conductor (38, 101) has two end regions (41, 42, 102, 103), which are arranged in the longitudinal direction of the radiofrequency hollow conductor (38, 101) on opposite sides, wherein at least one end region (41, 42, 102) of the radiofrequency hollow conductor (38, 101) is embodied to be open.

6. Magnetic resonance elastography apparatus (10) according to one of the preceding claims, characterised in that the elastography apparatus (30, 100) comprises a signal transmission unit (43), in order to transmit signals to the drive unit (32) arranged within the radiofrequency hollow conductor (38, 101), wherein the signal transmission unit (43) comprises at least one fiber optic cable (44).

7. Magnetic resonance elastography apparatus (10) according to claim 6, characterised in that the signal transmission unit (43) comprises at least one through filter (45).

8. Magnetic resonance elastography apparatus (10) according to claim 7, characterised in that the at least one through filter (45) is arranged in contact with the radiofrequency hollow conductor (38, 101) within the radiofrequency hollow conductor (38, 101).