JP2012205660A - Magnetic resonance imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the position of a receiving coil to be detected without moving a cradle in such a manner that a detecting section which detects the position of the tag of the receiving coil is included in the cradle.SOLUTION: The tag 43 in which identification information ID1 has been stored is built in the receiving coil 4. In the meantime, a plurality of readers Wi (i=1 to 10) for reading the identification information ID1 of the tag 43 which has been built in the receiving coil 4 are built in the cradle 31. When the receiving coil 4 is installed in the cradle 31, the tag 43 of the receiving coil 4 enters the inside of the readable region R of the reader Wwhich has been built in the cradle 31. Therefore, the installation position of the receiving coil 4 can be detected depending on which reader from among the readers Wto Wreads the identification information ID1 of the tag 43.

Description

  The present invention relates to a magnetic resonance imaging apparatus for detecting the position of a coil.

  Conventionally, a method for detecting the position of a receiving coil is known (see Patent Document 1).

JP 2009-398

Patent Document 1 discloses a method for detecting the position of a receiving coil when performing multi-station positioning imaging processing. However, in this method, when detecting the position of the receiving coil, it is necessary to detect the marker (bar code) of the receiving coil while moving the bed and to determine the moving distance of the bed when the marker (bar code) is detected. There is a problem that the detection processing of the position of the receiving coil is complicated. Patent Document 1 also discloses a method of detecting the installation position of the reception coil before moving the bed. In this method, a connector for fixing the reception coil to the bed, and this connector are disclosed. Since it is necessary to provide a slide for moving the bed, there is a problem that the structure of the bed becomes complicated.
Therefore, it is desired that the position of the receiving coil can be detected by a simple method without complicating the bed structure.

One aspect of the present invention is a magnetic resonance imaging apparatus including a coil that receives a magnetic resonance signal of a subject, and a cradle on which the subject is placed.
The coil has a tag for storing identification information;
The cradle has a detection unit that reads the identification information by performing wireless communication with the tag, and detects a position of the tag.
The magnetic resonance imaging apparatus detects the position of the coil based on the position of the tag.

  Since the detection unit for detecting the position of the tag of the reception coil is provided in the cradle, the position of the reception coil can be detected without moving the cradle. Moreover, since the detection unit detects the position of the tag by wireless communication, it is not necessary to provide the cradle with a connector for connecting the coil, a slide for moving the connector, etc., and the structure of the cradle is simple. Can be.

1 is a schematic diagram of a magnetic resonance imaging apparatus according to a first embodiment. FIG. 3 is a diagram showing a positional relationship between a cradle 31 and a receiving coil 4. It is explanatory drawing of the structure of the receiving coil. 3 is an explanatory diagram of an internal structure of a cradle 31. FIG. Reader _W 1 _{to W-10} is a diagram showing a region R that is capable of reading the identification information ID1. 4 is a diagram showing a positional relationship between a receiving coil 4 and a cradle 31. FIG. 4 is a diagram showing a positional relationship between a receiving coil 4 and a cradle 31. FIG. It is a figure which shows a mode when the to-be-examined object 12 is laid in the cradle 31 and the receiving coil 4 is installed. FIG. 3 is a diagram illustrating a state in which a subject 12 is transported to a bore 21. It is a figure which shows a scanning area | region. 2 is a diagram showing a cradle 31 and a receiving coil 4 installed in the cradle 31. FIG. It is a figure when the upper surface 4a and the lower surface 4b of the receiving coil 4 are turned upside down. It is the figure which looked at the cradle 31 and the receiving coil 4 installed in the cradle 31 from the upper side. It is a figure when the receiving coil 4 is reversed right and left. It is a figure which shows the cradle 31 and the receiving coil 4 in a 4th form.

  Hereinafter, although the form for inventing is demonstrated, this invention is not limited to the following forms.

(1) First Embodiment FIG. 1 is a schematic diagram of a magnetic resonance imaging apparatus according to a first embodiment.

  A magnetic resonance imaging apparatus (hereinafter referred to as “MRI apparatus”. MRI: Magnetic Resonance Imaging) 100 includes a magnet 2, a table 3, a receiving coil 4, and the like.

  The magnet 2 has a bore 21 in which the subject 12 is accommodated, a superconducting coil 22, a gradient coil 23, and a transmission coil 24. The superconducting coil 22 applies a static magnetic field B0, the gradient coil 23 applies a gradient magnetic field, and the transmission coil 24 transmits an RF pulse. In place of the superconducting coil 22, a permanent magnet may be used.

  The table 3 has a cradle 31. The cradle 31 is configured to be movable into the bore 21. The subject 12 is transported to the bore 21 by the cradle 31.

  The reception coil 4 is attached to the back of the subject 12. The receiving coil 4 has a plurality of coil elements (see FIG. 3). In the first embodiment, the installation position of the receiving coil 4 can be automatically detected. This detection method will be described in detail later.

  The MRI apparatus 100 further includes a sequencer 5, a transmitter 6, a gradient magnetic field power supply 7, a receiver 8, a central processing unit 9, an operation unit 10, and a display unit 11.

  Under the control of the central processing unit 9, the sequencer 5 sends information for imaging the subject 12 to the transmitter 6 and the gradient magnetic field power supply 7.

  The transmitter 6 outputs a drive signal for driving the RF coil 24 based on the information sent from the sequencer 5.

  The gradient magnetic field power supply 7 outputs a drive signal for driving the gradient coil 23 based on the information sent from the sequencer 5.

  The receiver 8 performs signal processing on the magnetic resonance signal received by the receiving coil 4 and outputs data obtained by the signal processing to the central processing unit 9.

  The central processing unit 9 implements various operations of the MRI apparatus 100 such as transmitting necessary information to the sequencer 5 and the display unit 11 and reconstructing an image based on data received from the receiver 8. The operation of each unit of the MRI apparatus 100 is controlled. The central processing unit 9 is constituted by a computer, for example. The central processing unit 9 includes a coil element selection unit 91 and the like.

  The coil element selection unit 91 selects a coil element to be used for receiving a magnetic resonance signal from a plurality of coil elements included in the reception coil 4.

The operation unit 10 is operated by the operator 13 and inputs various information to the central processing unit 9. The display unit 11 displays various information.
The MRI apparatus 100 is configured as described above.

Next, a method for detecting the installation position of the receiving coil 4 will be described.
FIG. 2 is a diagram illustrating a positional relationship between the cradle 31 and the receiving coil 4.
FIG. 2A is a diagram viewed from the upper side of the receiving coil 4, and FIG. 2B is a diagram viewed from the side of the receiving coil 4.

  In the first embodiment, the receiving coil 4 can be installed at any position with respect to the position in the z direction. However, with respect to the position in the x direction and the y direction, the installation position of the receiving coil 4 is determined in advance. Suppose that it is a fixed position. Therefore, in the first embodiment, the case where the position of the receiving coil 4 is detected only in the z direction will be described.

FIG. 3 is an explanatory diagram of the structure of the receiving coil 4.
3A is a perspective view of the receiving coil 4, FIG. 3B is a view seen through the inside of the receiving coil 4, and FIG. 3C is a side view of the inside of the receiving coil 4. FIG. It is the figure seen through from.

  The receiving coil 4 has coil elements 41 and 42 for receiving magnetic resonance signals from the subject 12. When the receiving coil 4 receives a magnetic resonance signal from the subject 12, one of the two coil elements 41 and 42 is selected. A method for selecting the coil element will be described later. In FIG. 3, the number of coil elements included in the receiving coil 4 is two for convenience of explanation, but the number of coil elements is not limited to two and may be three or more. . Here, for convenience of explanation, the number of coil elements included in the receiving coil 4 is two.

  The receiving coil 4 includes a tag 43 that stores the identification information ID1 of the receiving coil 4. The tag 43 will also be described later.

Next, the internal structure of the cradle 31 will be described.
FIG. 4 is an explanatory diagram of the internal structure of the cradle 31.

  4A is a perspective view of the cradle 31, FIG. 4B is a view of the inside of the cradle 31 seen through from above, and FIG. 4C is a view of the inside of the cradle 31 seen from the side. FIG.

The cradle 31 has a detection unit 31a. The detection unit 31a performs wireless communication with the tag 43 (see FIG. 3) of the reception coil 4, thereby reading the identification information ID1 and detecting the position of the tag 43 (see FIG. 3). The detection unit 31a includes a plurality of readers W _i (i = 1 to 10) that read the identification information ID1 of the tag 43. In the first embodiment, ten readers W _{1 to} W ₁₀ are built in, but the number of readers can be changed as needed. The readers W _{1 to} W ₁₀ are arranged in the z direction.

FIG. 5 is a diagram illustrating a region R in which the readers W _{1 to} W ₁₀ can read the identification information ID 1.

Each of the readers W _{1 to} W ₁₀ has a readable area R (indicated by a one-dot chain line) from which the identification information ID 1 stored in the tag 43 can be read, and the tag 43 can be read. When entering inside the region R, the identification information ID1 of the tag 43 can be read.

For example, the receiving coil 4, when installed as shown in FIG. 6, the tag 43, because it enters the inside of the readable area R of the reader W _5, can reader W ₅ reads the identification information ID1 . The receiving coil 4, when installed as shown in FIG. 7, the tag 43, because it enters the inside of the readable area R of the leader W _7, can reader W ₇ reads the identification information ID1 . Therefore, since the reader that reads the identification information ID1 differs depending on the position of the receiving coil 4, the installation position of the receiving coil 4 can be detected.
Note that the frequency used when performing wireless communication between the cradle 31 and the tag 43 is set to be different from the frequency used by the magnet 2.

Next, a procedure for imaging the subject 12 in the first embodiment will be specifically described.
8-10 is explanatory drawing of the procedure at the time of image | photographing the test object 12. FIG.

First, the subject 12 is placed on the cradle 31 and the receiving coil 4 is installed (see FIG. 8).
FIG. 8 is a diagram illustrating a state where the subject 12 is placed on the cradle 31 and the receiving coil 4 is installed.

  8A is a view of the subject 12 laid on the cradle 31 and the magnet 2 as viewed from above, and FIG. 8B is a view of FIG. 8A as viewed from the side.

In the first embodiment, the following (A) and (B) are defined as installation conditions for the receiving coil 4.
(A) The lower surface 4b of the receiving coil 4 is directed toward the cradle 31, and the upper surface 4a of the receiving coil 4 is directed toward the subject 12.
(B) toward the side where the reader _W 1 _{to W-10} sides 4e of the receiving coil 4 is arranged to direct the sides 4f of the receiver coil 4 on the opposite side (side not arranged reader _W 1 _{to W-10} is) .

Therefore, the operator installs the receiving coil 4 according to this installation condition. When the receiving coil 4 is installed according to this installation condition, the tag 43 built in the receiving coil 4 is positioned on any one of the readers W _{1 to} W ₁₀ , so that the identification information ID 1 of the tag 43 is identified. Can be read. In Figure 8, the tag 43, because it enters the inside of the readable area R of the leader _{W 7,} the reader _{W 7} reads the identification information ID1 tags 43. Therefore, the detection unit 31a can detect the position of the tag 43 in the z direction. Since the tag 43 is built in the receiving coil 4, the position of the receiving coil 4 can be detected by detecting the position of the tag 43.

  After the subject 12 is laid down and the receiving coil 4 is installed as described above, the subject 12 is transported to the bore 21 (see FIG. 9).

FIG. 9 is a diagram illustrating a state where the subject 12 is transported to the bore 21.
The cradle 31 moves by a distance D, and the subject 12 is transported to the bore 21. In FIG. 9, the receiving coil 4 before the subject 12 is transported to the bore 21 is indicated by a one-dot chain line. When the subject 12 is conveyed to the bore 21, a positioning scan for positioning the scan area is executed. The operator sets a scan area based on the image data obtained by the positioning scan (see FIG. 10).

FIG. 10 is a diagram illustrating a scan area.
When the scan region SR is set by the operator, the coil element selection unit 91 selects a coil element at a position closest to the scan region SR among the coil elements 41 and 42 of the reception coil 4. Since the scan area SR is set by the operator based on the image data obtained by the positioning scan, the coil element selection means 91 can recognize the position of the scan area SR in the bore 21. Further, since the position of the receiving coil 4 is known, the coil element selection means 91 can know the positional relationship between the scan region SR and the coil elements 41 and 42. Therefore, the coil element selection means 91 can select the coil element closest to the scan region SR among the coil elements 41 and 42. In FIG. 9, since the coil element 42 is close to the scan region SR, the coil element selection unit 91 selects the coil element 42. When the coil element 42 is selected, the scan region SR is scanned, and a magnetic resonance signal is received using the coil element 42.

  In the first embodiment, since the cradle 31 includes the detection unit 31a that detects the position of the tag 43 of the reception coil 4, the position of the reception coil 4 can be detected without moving the cradle 31. . In addition, since the detection unit 31a detects the position of the tag 43 by wireless communication, it is not necessary to provide the cradle 31 with a connector for connecting the receiving coil 4, a slide for moving the connector, and the like. The structure of the cradle 31 can be simplified.

  Further, since the installation position of the receiving coil 4 can be detected, the positional relationship between the coil elements 41 and 42 and the scan region SR can be recognized. Therefore, a coil element suitable for imaging of the scan region SR can be selected regardless of which part of the subject 12 the scan region SR is set.

In the first embodiment, in order to detect the installation position of the receiver coil 4, tag 43 contained in the receiving coil 4, it is necessary to enter the inside of the readable area R of the leader W _7. Therefore, if the readable area R of each of the readers W _{1 to} W ₁₀ is made too narrow, even if the receiving coil 4 is installed in the cradle, the tag 43 does not enter the readable area R, and the identification information ID1 of the tag 43 Cannot be read. For this reason, the width of the readable region R needs to be set so that the tag 43 can enter the readable region R when the receiving coil 4 is installed in the cradle 31. On the other hand, if the readable area R of each reader is excessively widened, when the receiving coil 4 is installed in the cradle, two or more readers simultaneously read the identification information ID1 of the tag 43, and the position of the receiving coil 43 is accurately determined. Can no longer be detected. Therefore, when the readers W _{1 to} W ₁₀ are built in the cradle 31, when the receiving coil 4 is installed in the cradle 31, only one reader out of the _ten readers W _{1 to} W ₁₀ has the tag 43. It is necessary to adjust the interval between adjacent readers so as to read the identification information ID1.

(2) Second Mode In the first mode, the receiving coil 4 includes only one tag, but may include a plurality of tags. In the second embodiment, a case where the reception coil 4 includes a plurality of tags will be described. In the second embodiment, the configuration other than the receiving coil 4 is the same as that of the first embodiment. Therefore, in the description of the second embodiment, the receiving coil will be mainly described.

  FIG. 11 is a diagram illustrating the cradle 31 and the receiving coil 4 installed in the cradle 31.

  FIG. 11A is a view of the cradle 31 and the receiving coil 4 as viewed from above, and FIG. 11B is a view as viewed from the side.

  The receiving coil 4 includes two tags 43 and 44. The tag 43 stores identification information ID1 of the receiving coil 4, and the tag 44 stores identification information ID2 different from the identification information ID1.

In FIG. 11, the tag 43 enters the readable area R of the reader W ₇ , and the tag 44 enters the readable area R of the reader W ₄ . Therefore, the reader W ₇ reads the identification information ID 1 of the tag 43, and the reader W ₄ reads the identification information ID ₂ of the tag 44. Therefore, the detection unit 31a of the cradle 31 can detect the positions of the tags 43 and 44 in the z direction. Since the tags 43 and 44 are built in the receiving coil 4, the position of the receiving coil 4 can be detected by detecting the positions of the tags 43 and 44.

  In FIG. 11, the lower surface 4b of the receiving coil 4 is directed to the cradle 31 (see FIG. 11B), but the upper surface 4a and the lower surface 4b of the receiving coil 4 may be turned upside down (FIG. 12). reference).

  FIG. 12 is a diagram when the upper surface 4a and the lower surface 4b of the receiving coil 4 are turned upside down. FIG. 12A is a view of the cradle 31 and the receiving coil 4 as viewed from above, and FIG. 12B is a view as viewed from the side.

In FIG. 12, contrary to FIG. 11, the reader W ₄ reads the identification information ID1, and the reader W ₇ reads the identification information ID2, so that it is possible to detect that the receiving coil 4 is installed upside down. . Therefore, the coil element selection means 91 (see FIG. 1) can correctly recognize the positions of the coil elements 41 and 42 regardless of which of the upper surface 4a and the lower surface 4b of the receiving coil 4 is directed to the cradle 31. it can. For this reason, in the second embodiment, in addition to the effect obtained in the first embodiment, the operator can also install the reception coil 4 without worrying about the vertical direction of the reception coil 4. .
In the second embodiment, the number of tags is two, but three or more tags may be provided.

(3) Third Embodiment In the third embodiment, differences from the second embodiment will be mainly described.

  FIG. 13 is a view of the cradle 31 and the receiving coil 4 installed in the cradle 31 as viewed from above.

In a third embodiment, the detection portion 31a of the cradle 31, in addition to the reader _W 1 _{to W-10,} and further includes a reader _W 11 _{to W-20.} In Figure 13, similarly to FIG. 11, can be based on the identification information ID1 and ID2 read by the reader _{W 7} and _{W 4,} it detects the installation position of the receiver coil 4. Since the two tags 43 and 44 are provided, the positions of the coil elements 41 and 42 can be correctly recognized even when the receiving coil 4 is turned upside down, as in the second embodiment.

  Furthermore, in the third embodiment, the side surface 4e and the side surface 4f of the receiving coil 4 may be reversed left and right (see FIG. 14).

FIG. 14 is a diagram when the receiving coil 4 is reversed left and right.
In FIG. 14, the reader W ₁₇ reads the identification information ID1, and the reader W ₁₄ reads the identification information ID2. Therefore, it can be detected that the receiving coil 4 is installed upside down. Therefore, in the third embodiment, in addition to the effects obtained in the first and second embodiments, the operator can also install the reception coil 4 without worrying about the left and right orientation of the reception coil 4. It is done.

(4) Fourth Embodiment FIG. 15 is a diagram showing the cradle 31 and the receiving coil 4 in the fourth embodiment.

  In the fourth embodiment, the readers W are arranged in a matrix so as to be arranged in n rows and m columns (4 rows and 10 columns in FIG. 15). By arranging the readers W in this way, in the fourth embodiment, in addition to the effects obtained in the first to third embodiments, the position of the receiving coil 4 is detected even if the receiving coil 4 is installed obliquely. The effect that it can do is acquired. In FIG. 15, the readers W are arranged in 4 rows and 10 columns, but the number of rows and the number of columns are not limited to this.

2 Magnet 3 Table 4 Receiving coil 5 Sequencer 6 Transmitter 7 Gradient magnetic field power supply 8 Receiver 9 Central processing unit 10 Operation unit 11 Display unit 12 Subject 13 Operator 21 Bore 22 Superconducting coil 23 Gradient coil 24 Transmitting coil 31 Cradle 91 Coil Element selection means 100 MRI apparatus

Claims (9)

A magnetic resonance imaging apparatus having a coil for receiving a magnetic resonance signal of a subject and a cradle on which the subject is placed,
The coil has a tag for storing identification information;
The cradle has a detection unit that reads the identification information by performing wireless communication with the tag, and detects a position of the tag.
A magnetic resonance imaging apparatus that detects the position of the coil based on the position of the tag.   The magnetic resonance imaging apparatus according to claim 1, wherein the detection unit includes a plurality of readers that read the identification information. The coil is configured to be installed at an arbitrary position with respect to a predetermined direction,
The magnetic resonance imaging apparatus according to claim 2, wherein the plurality of readers are arranged in the predetermined direction. The coil is configured to be installed at an arbitrary position with respect to a predetermined direction,
3. The reader according to claim 2, wherein some of the plurality of readers are arranged in the predetermined direction, and the remaining readers are arranged in the predetermined direction at positions different from the some readers. Magnetic resonance imaging equipment.   The partial readers are arranged on a first side surface of the cradle, and the remaining readers are arranged on a second side surface opposite to the first side surface. 5. The magnetic resonance imaging apparatus according to 4.   The magnetic resonance imaging apparatus according to claim 2, wherein the plurality of readers are arranged in n rows and m columns. Each of the plurality of readers has a readable area capable of reading the identification information,
The identification information of the tag is read according to any one of claims 2 to 6, when the tag enters the readable area of any one of the plurality of readers. Magnetic resonance imaging device. The coil includes a plurality of the tags,
The magnetic resonance imaging apparatus according to claim 1, wherein the plurality of tags have different identification information. The coil has a plurality of coil elements for receiving magnetic resonance signals of a subject,
Coil element selection means for selecting a coil element for receiving a magnetic resonance signal of the scan area from the plurality of coil elements based on the position of the coil and the position of the scan area of the subject; The magnetic resonance imaging apparatus according to claim 1, comprising:

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