MAGNETIC RESONANCE APPARATUS AND OPERATING METHOD THEREFOR

Abstract

In a magnetic resonance (MR) apparatus and an operating method wherein the MR apparatus has a scanner with a patient table that can be moved into a patient receiving region of the scanner, the patient table is held in an extended loading position, and three-dimensional scanning data describing the surface of a patient positioned in the loading position on the patient table are recorded with a 3D camera, which has a field of view that covers the patient table in the loading position. For the determination of at least one patient-related recording parameter, the scanning data are evaluated for the subsequent recording MR data.

Claims

1. A method for operating a magnetic resonance (MR) apparatus, said MR apparatus comprising an MR data acquisition scanner and a patient table movable into a patient receiving region of the MR data acquisition scanner, said method comprising: prior to operating the MR data acquisition scanner in order acquire MR data from a patient, placing the patient on the patient table at a loading position at which said patient table is adjacent to said MR data acquisition scanner, but not yet moved into said patient receiving region; holding said patient table in said loading position and operating a 3D camera, having a field of view that covers the patient table in the loading position, to acquire three-dimensional scanning data representing a surface of the patient in the loading position on the patient table; providing said scanning data to a processor and, in said processor, determining from said scanning data at least one patient-related recording parameter; and emitting said patient-related recording parameter from said processor as an electronic signal in a form for use in subsequent operation of said MR data acquisition scanner to acquire MR data from the patient in the patient receiving region.

2. A method as claimed in claim 1 comprising positioning said 3D camera centrally above said patient table.

3. A method as claimed in claim 1 comprising selecting said 3D camera from the group consisting of time-of-flight cameras and terahertz cameras.

4. A method as claimed in claim 1 comprising, in said processor, prior to determining said at least one patient-related recording parameter, bringing a coordinate system of the 3D camera and a coordinate system of the MR data acquisition scanner into registration with each other.

5. A method as claimed in claim 4 comprising bringing said coordinate system of the 3D camera and the coordinate system of the MR data acquisition scanner into registration by acquiring, in said scanning data, at least one feature of the patient table that is recognizable in said scanning data and, in said processor, comparing a position of said at least one feature with a known position of said patient table.

6. A method as claimed in claim 4 comprising taking movement of the patient table into account when bringing said coordinate system of the 3D camera and the coordinate system of the MR data acquisition scanner into registration.

7. A method as claimed in claim 1 comprising taking movement of said patient table into account for determining said at least one patient-related recording parameter.

8. A method as claimed in claim 1 comprising determining a receiving position of the patient table as a recording parameter.

9. A method as claimed in claim 1 comprising evaluating said scanning data in said processor to determine or adapt a surface model of the patient.

10. A method as claimed in claim 9 comprising, from said surface model of the patient, determining at least one patient parameter selected from the group consisting of an extent of the patient in a selected direction, the volume of the patient, the weight of the patient, and the body mass index of the patient, and adapting or selecting said at least one patient-related recording parameter dependent on said at least one patient parameter.

11. A method as claimed in claim 9 comprising, in said processor, prior to determining said at least one patient-related recording parameter, bringing a coordinate system of the 3D camera and a coordinate system of the MR data acquisition scanner into registration with each other, and, from said registration, determining a position, selected from the group consisting of a position of the patient and a position of a region of interest within the patient, and using said position to determine said patient-related recording parameter as a recording parameter that defines said patient receiving region.

12. A method as claimed in claim 1 comprising, during a preparation period in which said patient is positioned on the patient table, continuously acquiring said scanning data with said 3D camera until fulfillment of a positioning criterion that indicates occurrence of a final positioning of the patient with no covering objects on the patient that cannot be penetrated by the 3D camera and, in said processor, automatically evaluating said final position of the patient for use in determining said at least one patient-related recording parameter.

13. A method as claimed in claim 1 comprising placing a local coil, to be used with said MR data acquisition scanner in order to acquire the MR data from the patient, on the patient on the patient table in said loading position, and operating said 3D camera so that said scanning data includes a representation of said local coil, and, in said processor, determining at least one item of coil information describing said local coil from said scanning data.

14. A method as claimed in claim 12 comprising detecting said at least one item of coil information from the group consisting of coil identification information and coil model information, by detecting at least one characterizing feature of said local coil by image processing.

15. A method as claimed in claim 12 comprising detecting coil position information as said at least one item of coil information.

16. A method as claimed in claim 10 comprising, in said processor, evaluating said at least one item of coil information in order to set at least one additional recording parameter for operating said MR data acquisition scanner in order to acquire said MR data from the patient.

17. A method as claimed in claim 10 comprising using said at least one item of coil information to generate a notification that designates an error associated with said local coil, and emitting said notification from said processor at a user interface in communication with said processor.

18. A method as claimed in claim 1 comprising providing said at least one patient-related recording parameter at a user interface in communication with said processor, as a variable pre-selection available to an operator of the MR data acquisition scanner.

19. A method as claimed in claim 1 comprising providing said processor with at least one item of examination information that describes an examination to be performed with respect to said patient in said MR data acquisition scanner, and determining said at least one patient-related recording parameter dependent on said at least one item of examination information.

20. A magnetic resonance (MR) apparatus, comprising: an MR data acquisition scanner and a patient table movable into a patient receiving region of the MR data acquisition scanner; prior to operating the MR data acquisition scanner in order acquire MR data from a patient, the patient table being moved to a loading position at which said patient table is adjacent to said MR data acquisition scanner, but not yet moved into said patient receiving region, with a patient being placed on the patient table at said loading position, and said patient table being held in said loading position; a 3D camera, having a field of view that covers the patient table in the loading position, configured to acquire three-dimensional scanning data representing a surface of the patient in the loading position on the patient table; a processor provided with said scanning data, said processor being configured to determine from said scanning data, at least one patient-related recording parameter; and said processor being configured to emit said patient-related recording parameter from said processor as an electronic signal in a form for use in subsequent operation of said MR data acquisition scanner to acquire MR data from the patient in the patient receiving region.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1 schematically illustrates a magnetic resonance apparatus according to the invention.

[0025] FIG. 2 is a flowchart of an exemplary embodiment of the method according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] FIG. 1 is a schematic illustration of a scanner 1 of a magnetic resonance apparatus according to the invention. In FIG. 1, a section through the center of the scanner 1 is shown so that the patient receiving region 3 is also clearly identifiable. In this case, the scanner 1 has in addition to the basic field magnet 2, other customary components (not shown), such as a radio-frequency coil arrangement surrounding the patient receiving region 3 and a gradient coil arrangement surrounding the patient receiving region 3 and a cooling computer for the scanner 1, in addition to further customary components.

[0027] A patient support (not shown in further detail) is used to move a patient table 4, which in the present case is shown in a loading position outside the patient receiving region 3, into the patient receiving region 3, and back out. One possible position 5 within the patient receiving region 3 is indicated by dashed lines.

[0028] As can be seen, a 3D camera 7 is situated on the ceiling 6 of a room containing the scanner 1, centrally above the patient table 4 in the loading position. The field of view 8 of the 3D camera 7 permits a complete coverage of patient table 4 in the loading position and a patient 9 positioned on the patient table 4. Objects covering parts of the surface of the patient 9, such as local coil 10 to be placed thereupon, can also be detected in the three-dimensional scanning data of the 3D camera 7, which is here a time-of-flight camera.

[0029] The 3D camera 7 supplies scanning data acquired thereby to a control computer 11, which controls the operation of the entire magnetic resonance apparatus and which is also programmed to implement the method according to the invention.

[0030] FIG. 2 is a flowchart of an exemplary embodiment of the method according to the invention. In this case, ideally the 3D camera 7 is incorporated in the workflow of a magnetic resonance examination. In a step S1, a check is performed as to whether the patient table 4 is located in the loading position and whether a magnetic resonance examination is upcoming, as can be determined for example from examination information which can be entered by an operator and/or obtained from an information system. If this is the case, in a step S2 scanning data of the patient table 4 and objects located thereupon are recorded continuously. Unless there is already anyway a registration of the coordinate system of the 3D camera 7 and the coordinate system of the magnetic resonance scanner 1 to a fixed, known positioning of the 3D camera 7, registration can then take place in step S2 using the features of the patient table 4 obtained in the scanning data. In some exemplary embodiments, markers can be provided on the patient table 4, in order to simplify this process. The evaluation of features of the patient table 4 can be used to update an existing registration. The registration enables known movements of the patient table 4, controlled by the control computer 11, to be incorporated in all calculations containing scanning data, or based thereon.

[0031] In a step S3, a check is performed as to whether a positioning criterion for the patient 9 on the patient table 4 has occurred. This requires a patient 9 to be actually positioned on the patient table 4, which can be achieved by corresponding image processing measures and classification of the patient 9 in the scanning data. Also, there must be indications that the patient 9 is located in the patient's final position to be used for the recording of magnetic resonance data. For this purpose, it is possible for a corresponding actuating element to be used by the operator. It is also possible for this to be determined by image analysis of the scanning data, for example detecting that covering objects such as blankets/sheets and/or local coils 10 are arranged on the patient 9, and/or that the patient has not been moved for a long time.

[0032] If the positioning criterion has occurred, in a step S4, initially, scanning data are selected that are to be evaluated with respect to the surface of the patient 9. In this case, the scanning data ideally represent the surface of the patient 9 as completely as possible, which means as few as possible or no covering objects through which the 3D camera 7 is unable to scan are present. In this case, it is possible to use scan data that were recorded at a time before the occurrence of the positioning criterion, since the scanning data are retained for a predetermined period. Obviously scanning data should be selected with which the patient 9 was already in the position present at the time of the fulfillment of the positioning criterion.

[0033] The scanning data are subsequently evaluated. To this end, a model instance of a patient model, which is also provided with/or linked to an anatomical atlas, is adapted as a surface model to the surface of the patient 9 described by the scanning data so that, ideally, the outer surface thereof is completely described by the surface model. Then, patient parameters, in particular at least one extent and/or one volume and/or one weight and/or one body mass index of the patient are determined therefrom. Since, the field of interest within the patient 9 at which the upcoming magnetic resonance examination is directed is also known from the examination information, in addition to a position of the patient 9, a position or location of the region of interest within the patient 9 is also determined. The anatomical atlas is used for this purpose. This patient information, i.e. the patient parameters, and the positions are then used to determine patient-related recording parameters for the future recording of magnetic resonance data. For example, the BMI of the patient can be used as the basis for the selection of magnetic resonance sequences optimized for fat/thin patients, in this way an oversampling can be determined such that no wrapping artifacts occur, the receiving region can be defined with reference to the region of interest and/or it is possible for gradient directions, for example the phase-encoding direction, to be defined.

[0034] The recording parameters determined in this way are offered as a preselection in a step S5 at a user interface for setting recording parameters so that they can be easily accepted by an operator or, if required, changed once again. In other exemplary embodiments, it is also possible to automatically use the recording parameters directly.

[0035] In a step S6, the scanning data is further evaluated with respect to the fulfillment of a repositioning criterion, i.e. a subsequent change in the position of the patient 9, and with respect to other objects, which are represented by the scanning data and for which useful information can be derived in the workflow. If the repositioning criterion is fulfilled, the method branches back to step S4 with at least one part of the recording parameters being updated/re-determined in order to take account of the new position of the patient 9.

[0036] If it is desired to determine information on further objects, for example the local coil 10, the scanning data relative to these objects are evaluated in more detail in a step S7. Relative to the local coil 10, the detection of at least one characterizing feature of the local coil 10 in image processing, for example, enables the determination of identification information and/or coil model information as coil information. It is also possible to determine coil position information. This can also be taken into account when setting recording parameters; however, it is also possible for the coil information to be evaluated with respect to outputting information to an operator, for example if the incorrect local coil 10 is present and/or if said coil is positioned unfavorably. It is also possible for scanning data to be evaluated in respect of further objects, for example in order to ensure that no unwanted objects are moved into the patient receiving region 3 with the patient table 4 and the patient 9.

[0037] As soon as the patient table 4 is moved into the patient receiving region 3, the recording of scanning data with the 3D camera 7 is terminated.

[0038] Although modifications and changes may be suggested by those skilled in the art, it is the intention of the Applicant to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of the Applicant's contribution to the art.