TWO-DIMENSIONAL DISPLAY FOR MAGNETIC RESONANCE IMAGING

Abstract

Disclosed is a magnetic resonance imaging magnet assembly (102, 102′) configured for supporting a subject (118) within an imaging zone (108). The magnetic resonance imaging magnet assembly comprises a magnetic resonance imaging magnet (104), wherein the magnetic resonance imaging magnet is configured for generating a main magnetic field with the imaging zone. The magnetic resonance imaging magnet assembly further comprises an optical image generator (122) configured for generating a two-dimensional image. The magnetic resonance imaging magnet assembly further comprises an optical waveguide bundle (123) configured for coupling to the optical image generator. The magnetic resonance imaging magnet assembly further comprises a two-dimensional display (124) comprising pixels (600), wherein each of the pixels comprises a diffusor (602, 602′). Each of the pixels is optically coupled to at least one optical waveguide selected from the optical waveguide bundle, wherein the at least one optical waveguide of each of the pixels is configured for illuminating the diffusor. The optical waveguide bundle and the two-dimensional display are configured for displaying the two-dimensional image.

Claims

1. A magnetic resonance imaging magnet assembly configured for supporting a subject within an imaging zone, wherein the magnetic resonance imaging magnet assembly comprises: a magnetic resonance imaging magnet, wherein the magnetic resonance imaging magnet is configured for generating a main magnetic field with the imaging zone; an optical image generator configured for generating a two-dimensional image; an optical waveguide bundle configured for coupling to the optical image generator; a two-dimensional display comprising pixels, wherein each of the pixels comprises a diffusor, wherein the diffusor is a diffusor plate, wherein each of the pixels is optically coupled to at least one optical waveguide selected from the optical waveguide bundle, wherein the at least one optical waveguide of each of the pixels is configured for illuminating the diffusor, wherein the optical waveguide bundle and the two-dimensional display are configured for displaying the two-dimensional image.

2. The magnetic resonance imaging magnet assembly of claim 1, wherein the magnetic resonance imaging magnet assembly further comprises a subject support, wherein the optical waveguide bundle is integrated into the subject support.

3. The magnetic resonance imaging magnet assembly of claim 2, wherein the subject support comprises a support arch, wherein the two-dimensional display is attached to the support arch.

4. The magnetic resonance imaging magnet assembly of claim 1, wherein the magnetic resonance imaging magnet assembly comprises a gradient coil assembly, wherein the magnetic resonance imaging magnet assembly comprises a magnet cover encasing the magnetic resonance imaging magnet and the gradient coil assembly, wherein the two-dimensional display is any one of the following: integrated into the magnet cover and attached to the magnet cover, and wherein the optical waveguide bundle is attached to the magnet cover, wherein the optical waveguide bundle is between the gradient coil assembly and the magnet cover.

5. The magnetic resonance imaging magnet assembly of claim 4, wherein the magnetic resonance imaging magnet is a cylindrical magnet with a bore for receiving the subject, wherein the two-dimensional display is within the bore.

6. The magnetic resonance imaging magnet assembly of claim 5, wherein the optical image generator is attached to the magnetic resonance imaging magnet assembly, wherein the optical image generator is outside of bore.

7. The magnetic resonance imaging magnet assembly of claim 1, wherein the optical waveguide bundle is a three-dimensional printed optical waveguide bundle or formed from lithographically structured foils.

8. The magnetic resonance imaging magnet assembly of claim 1, wherein the optical waveguide bundle is formed from multiple optical fibers.

9. The magnetic resonance imaging assembly of claim 1, wherein optical waveguides of the optical wave guide bundle are configured for any one of the following: forming an optical coupling surface that abuts the diffusor of each voxel and forming the diffusor on an end surface of the optical wave guide

10. The magnetic resonance imaging assembly of claim 1, wherein the optical waveguides of the optical wave guide bundle comprise a reflective end surface, wherein the optical waveguides of the optical wave guide bundle are configured to couple to the diffusor using the reflective end surface.

11. A magnetic resonance imaging system comprising the magnetic resonance imaging magnet assembly of claim 1, wherein the magnetic resonance imaging system further comprises: a memory storing machine executable instructions and pulse sequence commands configured for controlling the magnetic resonance imaging system to acquire magnetic resonance imaging data (144); a processor configured for controlling the magnetic resonance imaging system, wherein execution of the machine executable instructions causes the processor to: acquire the magnetic resonance imaging data by controlling the magnetic resonance imaging system with the pulse sequence commands; and control the optical image generator to generate the two-dimensional image during the acquisition of the magnetic resonance imaging data.

12. The magnetic resonance imaging system of claim 11, wherein the magnetic resonance imaging system further comprises a subject motion detection system configured for acquiring subject motion during the acquisition of the magnetic resonance imaging data, wherein execution of the machine executable instructions further cause the processor to: control the subject motion detection system to acquire the subject motion data during the acquisition of the magnetic resonance imaging data; and control the optical image indicator to render a motion feedback indicator within the two-dimensional image using the subject motion data.

13. The magnetic resonance imaging system of claim 12, wherein the subject motion detection system comprises any one of the following: a body position sensor, a camera system, a respiration tube, a respiration monitor belt, a magnetic resonance imaging navigator, and combinations thereof.

14. The magnetic resonance imaging system of claim 12, wherein the optical image indicator is configured for displaying any one of the following: a breath hold indicator, a breathing state of the subject, a body position of the subject, and combinations thereof.

15. The magnetic resonance imaging system of claim 11, wherein execution of the machine executable instructions further causes the processor to control the optical image generator to perform any one of the following: render a chosen color pattern; render a chosen color gradient; render a chosen brightness gradient; and combinations thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In the following preferred embodiments of the invention will be described, by way of example only, and with reference to the drawings in which:

[0053] FIG. 1 illustrates an example of a magnetic resonance imaging system;

[0054] FIG. 2 illustrates a further example of a magnetic resonance imaging system:

[0055] FIG. 3 shows a flow chart which illustrates a method of operating either the magnetic resonance imaging system of FIG. 1 or FIG. 2;

[0056] FIG. 4 illustrates an example of a two-dimensional image which renders an example of a motion feedback indicator;

[0057] FIG. 5 illustrates a two-dimensional display integrated into a magnetic resonance imaging magnet;

[0058] FIG. 6 shows an alternative view of the two-dimensional display of FIG. 5;

[0059] FIG. 7 illustrates a method of coupling the optical wave guide bundle to the two-dimensional display;

[0060] FIG. 8 illustrates a further method of coupling the optical wave guide bundle to the two-dimensional display; and

[0061] FIG. 9 illustrates a further method of coupling the optical wave guide bundle to the two-dimensional display.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0062] Like numbered elements in these figures are either equivalent elements or perform the same function. Elements which have been discussed previously will not necessarily be discussed in later figures if the function is equivalent.

[0063] FIG. 1 illustrates an example of a magnetic resonance imaging system 100. The magnetic resonance imaging system 100 comprises a magnetic resonance imaging magnet assembly 102 and a computer system 126.

[0064] The magnetic resonance imaging magnet assembly 102 comprises a magnet 104. The magnet 104 is a superconducting cylindrical type magnet with a bore 106 through it. The use of different types of magnets is also possible; for instance it is also possible to use both a split cylindrical magnet and a so called open magnet. A split cylindrical magnet is similar to a standard cylindrical magnet, except that the cryostat has been split into two sections to allow access to the iso-plane of the magnet, such magnets may for instance be used in conjunction with charged particle beam therapy. An open magnet has two magnet sections, one above the other with a space in-between that is large enough to receive a subject: the arrangement of the two sections area similar to that of a Helmholtz coil. Open magnets are popular, because the subject is less confined. Inside the cryostat of the cylindrical magnet there is a collection of superconducting coils. Within the bore 106 of the cylindrical magnet 104 there is an imaging zone 108 where the magnetic field is strong and uniform enough to perform magnetic resonance imaging. A region of interest 109 is shown within the imaging zone 108. The magnetic resonance data is typically acquired for the region of interest. A subject 118 is shown as being supported by a subject support 120 such that at least a portion of the subject 118 is within the imaging zone 108 and the region of interest 109.

[0065] Within the bore 106 of the magnet there is also a set of magnetic field gradient coils 110 which is used for acquisition of preliminary magnetic resonance data to spatially encode magnetic spins within the imaging zone 108 of the magnet 104. The magnetic field gradient coils 110 connected to a magnetic field gradient coil power supply 112. The magnetic field gradient coils 110 are intended to be representative. Typically magnetic field gradient coils 110 contain three separate sets of coils for spatially encoding in three orthogonal spatial directions. A magnetic field gradient power supply supplies current to the magnetic field gradient coils. The current supplied to the magnetic field gradient coils 110 is controlled as a function of time and may be ramped or pulsed.

[0066] Adjacent to the imaging zone 108 is a radio-frequency coil 114 for manipulating the orientations of magnetic spins within the imaging zone 108 and for receiving radio transmissions from spins also within the imaging zone 108. The radio frequency antenna may contain multiple coil elements. The radio frequency antenna may also be referred to as a channel or antenna. The radio-frequency coil 114 is connected to a radio frequency transceiver 116. The radio-frequency coil 114 and radio frequency transceiver 116 may be replaced by separate transmit and receive coils and a separate transmitter and receiver. It is understood that the radio-frequency coil 114 and the radio frequency transceiver 116 are representative. The radio-frequency coil 114 is intended to also represent a dedicated transmit antenna and a dedicated receive antenna. Likewise the transceiver 116 may also represent a separate transmitter and receivers. The radio-frequency coil 114 may also have multiple receive/transmit elements and the radio frequency transceiver 116 may have multiple receive/transmit channels. For example if a parallel imaging technique such as SENSE is performed, the radio-frequency could 114 will have multiple coil elements.

[0067] Within the bore of the magnet 106 there can be seen that there is a two-dimensional display 124 that is attached to an interior surface. This for example may be attached to a magnet cover or embedded within it. The magnet cover is not shown in this Figure. There is an optical image generator 122 that is located out of the bore 106 of the magnet 104. Between the optical image generator 122 and the two-dimensional display 124 is an optical waveguide bundle 123. The optical waveguide bundle 123 couples the two-dimensional display 124 to the optical image generator 122. Details regarding the two-dimensional display 124 are discussed in later Figures.

[0068] The transceiver 116 and the gradient controller 112 are shown as being connected to a hardware interface 128 of a computer system 126. The computer system further comprises a processor 130 that is in communication with the hardware system 128, a memory 134, and a user interface 132. The memory 134 may be any combination of memory which is accessible to the processor 130. This may include such things as main memory, cached memory, and also non-volatile memory such as flash RAM, hard drives, or other storage devices. In some examples the memory 134 may be considered to be a non-transitory computer-readable medium.

[0069] The memory 134 is shown as containing machine-executable instructions 140. The machine-executable instructions 140 enable the processor 130 to control the operation and function of the magnetic resonance imaging system 100. The machine-executable instructions 140 may also enable the processor 130 to perform various data analysis and calculation functions. The computer memory 134 is further shown as containing pulse sequence commands 142.

[0070] The pulse sequence commands 142 enable the magnetic resonance imaging system to acquire magnetic resonance imaging data according to a magnetic resonance imaging protocol. The memory 134 is further shown as containing magnetic resonance imaging data 144 that has been acquired by controlling the magnetic resonance imaging system 100 with the pulse sequence commands 142. In the example shown in FIG. 1 there may be an optional subject motion detection system.

[0071] In this example the magnetic resonance imaging system 100 itself is the motion detection system. The pulse sequence commands 142 can be modified to also acquire navigator data 146. This may for example be useful for monitoring the breathing phase and/or heart phase of the subject 118. The memory 134 is shown as containing navigator data 146 that was acquired at the same time or interleaved with the acquisition of the magnetic resonance imaging data 144. The navigator data 146 may be the subject motion data and may be used to generate a motion feedback indicator 148. The motion feedback indicator 148 can be rendered on the two-dimensional display 124. This may be useful in the subject 118 controlling his or her position and/or breathing phase. The memory 134 is further shown as containing a magnetic resonance image 150 that was reconstructed from the magnetic resonance imaging data 144.

[0072] FIG. 2 illustrates a further example of a magnetic resonance imaging system 200. The magnetic resonance imaging system 200 is similar to the magnetic resonance imaging system 100 of FIG. 1 with several modifications. The magnetic resonance imaging magnet assembly 102′ has been modified such that the optical image generator 122 is located on or near to the subject support 120 and the optical waveguide bundle 123 is routed through or is attached to the subject support 120. The two-dimensional display 124 is supported above the head of the subject 118 by a support arch 202. This holds the two-dimensional display 124 in a fixed position with relation to the subject 118 even if the subject support 120 is moved in and out of the bore 106 of the magnet 104. There is optionally a camera 204 attached to the support arch 202. The camera 204 may be used to acquire camera data 146′ that in this case may be the subject motion data.

[0073] FIG. 3 shows a flowchart which illustrates a method of operating the magnetic resonance imaging system 100 of FIG. 1 or the magnetic resonance imaging system 200 of FIG. 2. First in step 300 the magnetic resonance imaging system 100, 200 is controlled with the pulse sequence commands 142. This causes the magnetic resonance imaging system 100, 200 to acquire the magnetic resonance imaging data 144. Next in step 302 the processor 130 controls the optical image generator 122 to generate the two-dimensional image during the acquisition of the magnetic resonance imaging data 144. For example, during the execution of the pulse sequence commands. The method then proceeds to step 304 which is optional. The subject motion detection system which in FIG. 1 is the magnetic resonance imaging system or in FIG. 2 the camera system 204, to acquire the subject motion data 146, 146′ during the acquisition of the magnetic resonance imaging data 144. The method then proceeds optionally onto step 306 which control the optical image indicator to render the motion feedback indicator 148 as the two-dimensional image using the subject motion data to control the motion feedback indicator.

[0074] FIG. 4 illustrates an example of a two-dimensional image 400 which renders an example of a motion feedback indicator 148. In this example there are two circles, 402, 404. The first circle 402 represents an initial position of the subject and the second circle 404 represents a current position of the subject 404. The distance between the centers of the circle may for example be used to represent a change in a breathing phase or a more complex measurement of the subject's position may be mapped to a change in both the distance and/or orientation of the circles 402, 404.

[0075] Examples may provide for a means to transfer an image (two-dimensional image) into the MRI bore through light guides in order to avoid any type of electromagnetic interference problems. This can be, for example, a bundle of glass fibers as shown in FIG. 5 below.

[0076] FIG. 5 illustrates an example of a two-dimensional display 124 such as would be present in the magnetic resonance imaging magnet assembly 102. Within the bore 106 of the magnet 104 the two-dimensional display 124 is shown as being integrated into a magnet cover 500. The optical waveguide bundle 123 is shown as going through the magnet cover 500 to the two-dimensional display 124. In this example the optical waveguide bundle 123 is a collection of fiber optic waveguides. In other examples the optical waveguide bundle 123 could be manufactured into or 3D printed into the magnet cover 500 or formed from lithographically structured foils.

[0077] FIG. 6 shows an example of a two-dimensional display 124 in greater detail. In this example the two-dimensional display 124 is again mounted on the magnet cover 500, however the same display could be mounted on the support arch 202. The two-dimensional display 124 comprises a number of pixels 600. Each pixel 600 comprises a diffuser 602 and at least one optical waveguide 604 which is coupled to it. The diffuser 602 takes light from the optical waveguide 604 and makes it appear uniform across the surface of the pixel. This for example enables the subject to see and interpret the two-dimensional display 124 even when the angle of the subject with respect to the two-dimensional display 124 is not optimal.

[0078] In the example of FIG. 5, one could project an image into one end of the fiber bundle. On the other end of the bundle, the fiber tips could make a bend and stick out into the MRI bore and are visible to the patient (see FIG. 9 below). Here, they can be arranged to form a two-dimensional display (see FIG. 7). The fiber diameter can be quite small, so in order to widen the pixels, one could terminate them with diffusor plates (FIGS. 7 and 8). FIGS. 7, 8 and 9 illustrate different ways of coupling the optical waveguide bundle to the two-dimensional display 124.

[0079] As an alternative to bending the fibers, one could also decouple the light by means of reflection at fiber ends honed and chamfered to 45°, This is illustrated in FIG. 7 below. Alternatively, instead of fibers, one could also use lithographically structured foil or a 3D printed waveguide structure.

[0080] FIG. 7 shows one example where an optical waveguide 604 has a reflective end 702. For example, the reflective end 702 could be polished and optionally coated with a mirror surface. This causes light 706 to be reflected through an optical coupler and then into the diffuser 602. The combination of the diffuser 602 and the coupler 704 forms one pixel 600 of the two-dimensional display 124. This may be replicated in other pixels 600. In this example the optical waveguide 604 was a fiber optic. Although a fiber optic is illustrated other types of waveguides such as a 3D-printed or polymer waveguide may also be used. The fiber optic 604 is shown as also optionally having a covering 700 for protecting the fiber 604. In some examples the optical coupler 604 is not used and the light 706 couples directly from the reflective end surface 702 to the diffuser 602.

[0081] FIG. 8 shows an alternative method of coupling light 706 into the diffusers 602 to form individual pixels 600. In the example the reflective end 702 is not used. Instead the fiber optic 604 is bent such that an optical coupling surface 800 abuts the diffuser 602 and the light 706 is then coupled.

[0082] FIG. 9 illustrates a further alternative for coupling the waveguides 604 to the two-dimensional display 124. In this example the waveguide 604 has a flaring structure 900 which transitions directly into the diffuser 602′. The structure illustrated in FIG. 9 may for example be representative of a system which is manufactured by three-dimensional printing. The diffuser 602′ could for example be a different material that is printed and then the flaring structure 900 is printed and then finally, the optical waveguide 604 that connect with it. In another alternative the flaring structure 900 has its surface treated for example the end region may be frosted and this may be used to form the diffuser 602′.

[0083] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments.

[0084] Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. A computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. Any reference signs in the claims should not be construed as limiting the scope.

LIST OF REFERENCE NUMERALS

[0085] 100 magnetic resonance imaging system

[0086] 102 magnetic resonance imaging magnet assembly

[0087] 102′ magnetic resonance imaging magnet assembly

[0088] 104 magnet

[0089] 106 bore of magnet

[0090] 108 imaging zone

[0091] 109 region of interest

[0092] 110 magnetic field gradient coils

[0093] 112 magnetic field gradient coil power supply

[0094] 114 radio-frequency coil

[0095] 116 transceiver

[0096] 118 subject

[0097] 120 subject support

[0098] 122 optical image generator

[0099] 123 optical waveguide bundle

[0100] 124 two-dimensional display

[0101] 126 computer system

[0102] 128 hardware interface

[0103] 130 processor

[0104] 132 user interface

[0105] 134 computer memory

[0106] 140 machine executable instructions

[0107] 142 pulse sequence commands

[0108] 144 magnetic resonance imaging data

[0109] 146 navigator data (subject motion data)

[0110] 146′ camera data (subject motion data)

[0111] 148 motion feedback indicator

[0112] 150 magnetic resonance image

[0113] 200 magnetic resonance imaging system

[0114] 202 support arch

[0115] 204 camera

[0116] 300 acquire the magnetic resonance imaging data by controlling the magnetic resonance imaging system with the pulse sequence commands

[0117] 302 control the optical image generator to generate the two-dimensional image during the acquisition of the magnetic resonance imaging data

[0118] 304 control the subject motion detection system to acquire the subject motion data during the acquisition of the magnetic resonance imaging data

[0119] 306 control the optical image indicator to render a motion feedback indicator within the two-dimensional image using the subject motion data

[0120] 400 two dimensional image

[0121] 402 initial position

[0122] 404 current position

[0123] 500 magnet cover

[0124] 600 pixel

[0125] 602 diffusor

[0126] 602′ diffusor

[0127] 604 optical waveguide

[0128] 700 optional covering

[0129] 702 reflective end

[0130] 704 optical coupler

[0131] 706 light coupled to diffusor

[0132] 800 optical coupling surface

[0133] 900 flaking