JP7123629B2 - MAGNETIC RESONANCE IMAGING DEVICE AND CONDUCTIVITY CONFIRMATION METHOD - Google Patents

Description

TECHNICAL FIELD Embodiments of the present invention relate to a magnetic resonance imaging apparatus and a conduction confirmation method.

Conventionally, a magnetic resonance imaging apparatus includes a receiving coil for receiving a magnetic resonance signal generated from a subject, a receiving circuit for generating magnetic resonance signal data on which an image is based from the magnetic resonance signal received by the receiving coil, A bed or the like on which the subject is placed is provided. In such a magnetic resonance imaging apparatus, a bed is generally provided with a port for inputting a magnetic resonance signal received by a receiving coil, and a transmission path is provided between the port and the receiving circuit. magnetic resonance signals are transmitted through.

JP 2009-276236 A JP 2017-185128 A

The problem to be solved by the present invention is to easily confirm continuity of a transmission line between a port of a bed and a receiving circuit.

A magnetic resonance imaging apparatus according to an embodiment includes a receiving coil, a bed, a receiving circuit, an image generating section, and a specifying section. The receiving coil has a plurality of coil elements, and each coil element receives a magnetic resonance signal generated from the subject. The bed has a port to which the receiving coil is connected, and the subject is placed thereon. The receiving circuit generates magnetic resonance signal data based on the magnetic resonance signal input from the port. The image generator generates an image based on the magnetic resonance signal data. The specifying unit specifies a continuity state between the port and the receiving circuit. The port has a plurality of terminals for inputting magnetic resonance signals received by the plurality of coil elements. The port and the receiving circuit are connected by a plurality of transmission paths for transmitting magnetic resonance signals input from the plurality of terminals. The image generator generates an image for each of some of the plurality of transmission paths. The identification unit identifies a transmission line in which disconnection has occurred among the plurality of transmission lines based on the image generated for each of the partial transmission lines.

FIG. 1 is a diagram showing a configuration example of a magnetic resonance imaging (MRI) apparatus according to this embodiment. FIG. 2 is a diagram showing a configuration example of a bed according to this embodiment. FIG. 3 is a diagram showing an example of connection between the ports of the bed and the local coils according to the present embodiment. FIG. 4 is a diagram showing an example of a transmission line between the port of the bed and the receiving circuit according to this embodiment. FIG. 5 is a diagram showing an example of transmission path identification by the image generation function and the identification function according to the present embodiment. FIG. 6 is a diagram showing an example of TDR measurement by a TDR (Time Domain Reflectometry) measuring instrument according to this embodiment. FIG. 7 is a diagram showing an example of transmission line switching by the switching function according to the present embodiment. FIG. 8 is a flow chart showing the flow of the conduction confirmation method according to this embodiment.

Hereinafter, embodiments of a magnetic resonance imaging apparatus and a conduction confirmation method will be described in detail with reference to the drawings.

(embodiment)
FIG. 1 is a diagram showing a configuration example of an MRI apparatus according to this embodiment.

For example, as shown in FIG. 1, the MRI apparatus 100 according to the present embodiment includes a static magnetic field magnet 1, a gradient magnetic field coil 2, a gradient magnetic field power supply 3, a whole body (WB) coil 4, a bed 5, and a transmission circuit 6. , a local coil 7, a distribution board 8, a receiving circuit 9, a high frequency shield 10, a pedestal 11, an interface 12, a display 13, a memory circuit 14, a bed control board 15, and processing circuits 16-18.

The static magnetic field magnet 1 generates a static magnetic field in an imaging space in which the subject S is arranged. Specifically, the static magnetic field magnet 1 is formed in a hollow, substantially cylindrical shape (including one having an elliptical cross-sectional shape perpendicular to the central axis of the cylinder), and an imaging space arranged in the cylinder. to generate a static magnetic field. For example, the static magnetic field magnet 1 has a substantially cylindrical cooling container and a magnet such as a superconducting magnet immersed in a coolant (for example, liquid helium) filled in the cooling container. Here, for example, the static magnetic field magnet 1 may use a permanent magnet to generate a static magnetic field.

The gradient magnetic field coil 2 is arranged inside the static magnetic field magnet 1 and generates gradient magnetic fields along a plurality of axial directions in an imaging space where the subject S is arranged. Specifically, the gradient magnetic field coil 2 is formed in a hollow, substantially cylindrical shape (including one having an elliptical cross-sectional shape perpendicular to the central axis of the cylinder), and an imaging space arranged in the cylinder. , a gradient magnetic field is generated along each of the X-axis, Y-axis, and Z-axis, which are orthogonal to each other. Here, the X-axis, Y-axis, and Z-axis constitute an apparatus coordinate system unique to the MRI apparatus 100 . For example, the Z axis coincides with the axis of the cylinder of the gradient coil 2 and is set along the magnetic flux of the static magnetic field generated by the static magnetic field magnet 1 . The X-axis is set along the horizontal direction perpendicular to the Z-axis, and the Y-axis is set along the vertical direction perpendicular to the Z-axis.

The gradient magnetic field power supply 3 supplies a current to the gradient magnetic field coil 2 to generate a gradient magnetic field in the space inside the gradient magnetic field coil 2 along each of the X-axis, Y-axis, and Z-axis directions. In this way, the gradient magnetic field power supply 3 generates gradient magnetic fields along the respective axial directions of the X-axis, the Y-axis and the Z-axis. can be generated.

Here, each axis along the readout direction, phase encoding direction, and slice direction constitutes a logical coordinate system for defining a slice region or volume region to be imaged. Hereinafter, the gradient magnetic field along the readout direction is called the readout gradient magnetic field, the gradient magnetic field along the phase encode direction is called the phase encode gradient magnetic field, and the gradient magnetic field along the slice direction is called the slice gradient magnetic field. .

Specifically, each of the readout gradient magnetic field, the phase-encoding gradient magnetic field, and the slice gradient magnetic field is superimposed on the static magnetic field generated by the static magnetic field magnet 1, and the magnetic resonance generated from the subject S (Magnetic Resonance: MR) to give spatial position information to the signal. The readout gradient magnetic field changes the frequency of the MR signal according to the position in the readout direction, thereby imparting positional information along the readout direction to the MR signal. The phase-encoding gradient magnetic field changes the phase of the MR signal along the phase-encoding direction, thereby imparting position information in the phase-encoding direction to the MR signal. The slice gradient magnetic field imparts positional information along the slice direction to the MR signal. For example, if the imaging region is a slice region, the slice gradient magnetic field is used to determine the direction, thickness, and number of slice regions. is used to change the phase of the MR signal.

The WB coil 4 is arranged inside the gradient magnetic field coil 2, and has the function of a transmission coil that applies a high-frequency magnetic field to the imaging space in which the subject S is placed, and the effect of the high-frequency magnetic field generated from the subject S. It is a radio frequency coil that has the function of a receiving coil for receiving MR signals. Specifically, the WB coil 4 is formed in a hollow, substantially cylindrical shape (including one having an elliptical cross-sectional shape perpendicular to the central axis of the cylinder), and the high-frequency pulse supplied from the transmission circuit 6 is applied to the WB coil 4 . Based on the signal, a high frequency magnetic field is applied to the imaging space arranged within the cylinder. The WB coil 4 also receives MR signals generated from the subject S under the influence of the high-frequency magnetic field, and outputs the received MR signals to the receiving circuit 9 .

The bed 5 includes a tabletop 51 on which the subject S is placed, and when the subject S is imaged, the tabletop 51 on which the subject S is placed is moved to the imaging space. For example, the bed 5 is installed so that its longitudinal direction is parallel to the central axis of the static magnetic field magnet 1 .

The transmission circuit 6 outputs to the WB coil 4 a high-frequency pulse signal corresponding to the Larmor frequency specific to the target nucleus placed in the static magnetic field. Specifically, the transmission circuit 6 has a pulse generator, a high frequency generator, a modulator, and a high frequency amplifier. A pulse generator generates a waveform of a high frequency pulse signal. A radio frequency generator generates a radio frequency signal at a resonance frequency. The modulator generates a high frequency pulse signal by modulating the amplitude of the high frequency signal generated by the high frequency generator with the waveform generated by the pulse generator. The high frequency amplifier amplifies the high frequency pulse signal generated by the modulator and outputs it to the WB coil 4 .

The local coil 7 is a high frequency coil having the function of a receiving coil for receiving MR signals generated from the subject S. Specifically, the local coil 7 is attached to the subject S placed inside the WB coil 4, and receives MR signals generated from the subject S under the influence of the high-frequency magnetic field applied by the WB coil 4, It outputs the received MR signal to the receiving circuit 9 . Note that the local coil 7 may further have a function of a transmission coil that applies a high-frequency magnetic field to the subject S. In that case, the local coil 7 is connected to the transmission circuit 6 and applies a high frequency magnetic field to the subject S based on the high frequency pulse signal supplied from the transmission circuit 6 .

The distribution board 8 outputs the MR signals output from the WB coil 4 and the local coil 7 to the receiving circuit 9 for each coil.

The receiving circuit 9 generates MR signal data based on the MR signals received by the WB coil 4 and the local coil 7 and outputs the generated MR signal data to the processing circuit 16 . Specifically, the receiving circuit 9 has a preamplifier, a detector, and an A/D (Analog/Digital) converter. The preamplifier amplifies the MR signal output from the distribution board 8 . The detector detects an analog signal obtained by subtracting the resonance frequency component from the MR signal amplified by the preamplifier. The A/D converter converts the analog signal detected by the detector into a digital signal to generate MR signal data, and outputs the generated MR signal data to the processing circuit 16 .

The high-frequency shield 10 is arranged between the gradient magnetic field coil 2 and the WB coil 4 and shields the gradient magnetic field coil 2 from the high-frequency magnetic field generated by the WB coil 4 . Specifically, the high-frequency shield 10 is formed in a hollow, substantially cylindrical shape (including one having an elliptical cross-sectional shape perpendicular to the central axis of the cylinder), and is positioned on the inner peripheral side of the gradient coil 2. It is arranged in the space so as to cover the outer peripheral surface of the WB coil 4 .

The pedestal 11 accommodates the static magnetic field magnet 1 , the gradient magnetic field coil 2 , the WB coil 4 and the high frequency shield 10 . Specifically, the frame 11 has a cylindrical hollow bore B, and the static magnetic field magnet 1, the gradient magnetic field coil 2, the WB coil 4, and the high frequency shield 10 are arranged so as to surround the bore B. Each of them is housed in the same state. Here, the space inside the bore B of the gantry 11 serves as an imaging space in which the subject S is arranged when the subject S is imaged.

Here, an example in which the MRI apparatus 100 has a so-called tunnel configuration in which the static magnetic field magnet 1, the gradient magnetic field coil 2, and the WB coil 4 are each formed in a substantially cylindrical shape will be described. is not limited to this. For example, the MRI apparatus 100 has a so-called open configuration in which a pair of static magnetic field magnets, a pair of gradient magnetic field coils, and a pair of high-frequency coils are arranged to face each other across an imaging space in which the subject S is arranged. You may have

The interface 12 receives various instructions and various information input operations from the operator. Specifically, the interface 12 is connected to the processing circuit 18 , converts an input operation received from the operator into an electrical signal, and outputs the electrical signal to the processing circuit 18 . For example, the interface 12 includes a trackball, a switch button, a mouse, a keyboard, a touch pad for performing input operations by touching the operation surface, a display screen, and the like for setting imaging conditions and regions of interest (ROI). It is realized by a touch screen integrated with a touch pad, a non-contact input circuit using an optical sensor, an audio input circuit, and the like. In this specification, the interface 12 is not limited to having physical operation parts such as a mouse and a keyboard. For example, the interface 12 also includes an electrical signal processing circuit that receives an electrical signal corresponding to an input operation from an external input device provided separately from the device and outputs the electrical signal to the control circuit.

The display 13 displays various information and various images. Specifically, the display 13 is connected to the processing circuit 18 and converts various information and image data sent from the processing circuit 18 into electrical signals for display and outputs the electrical signals. For example, the display 13 is realized by a liquid crystal monitor, a CRT (Cathode Ray Tube) monitor, a touch panel, or the like.

The storage circuit 14 stores various data. Specifically, the storage circuit 14 stores MR signal data and image data. For example, the storage circuit 14 is implemented by a semiconductor memory device such as a RAM (Random Access Memory), a flash memory, a hard disk, an optical disk, or the like.

The bed control board 15 is provided on the bed 5 and controls the operation of the bed 5 by outputting electrical signals for control to the bed 5 . For example, the bed control board 15 receives an instruction from the operator via the interface 12 to move the table top 51 in the longitudinal direction, the vertical direction, or the horizontal direction. The movement mechanism of the top board 51 which 5 has is operated.

The processing circuitry 16 has a data collection function 161 . The data acquisition function 161 acquires MR signal data of the subject S by driving the gradient magnetic field power supply 3, the transmission circuit 6, and the reception circuit 9. FIG.

Specifically, the data acquisition function 161 acquires MR signal data by executing various pulse sequences based on sequence execution data output from the processing circuit 18 . Here, the sequence execution data is information defining a pulse sequence indicating a procedure for acquiring MR signal data. Specifically, the sequence execution data includes the timing and strength of the current supplied by the gradient magnetic field power supply 3 to the gradient magnetic field coil 2, the strength of the high-frequency pulse signal supplied to the WB coil 4 by the transmission circuit 6, and the supply voltage. This information defines the timing, the detection timing at which the receiving circuit 9 detects the MR signal, and the like.

Then, the data acquisition function 161 receives MR signal data from the receiving circuit 9 as a result of executing various pulse sequences, and stores the received MR signal data in the storage circuit 14 . The set of MR signal data received by the data acquisition function 161 is arranged two-dimensionally or three-dimensionally according to the positional information provided by the readout magnetic field gradient, the phase encoding magnetic field gradient, and the slice magnetic field gradient. Thus, it is stored in the storage circuit 14 as data forming the k-space.

The processing circuitry 17 has an image generation function 171 . The image generation function 171 generates an image based on the MR signal data stored in the storage circuit 14. FIG. Specifically, the image generation function 171 reads the MR signal data stored in the storage circuit 14 by the data collection function 161, and performs post-processing, that is, reconstruction processing such as Fourier transform on the read MR signal data. to generate the image. The image generation function 171 also causes the storage circuit 14 to store the image data of the generated image.

Processing circuitry 18 has a main control function 181 . The main control function 181 performs overall control of the MRI apparatus 100 by controlling each component of the MRI apparatus 100 . For example, the main control function 181 receives input of imaging conditions from the operator via the interface 12 . Then, the main control function 181 generates sequence execution data based on the received imaging conditions, and transmits the sequence execution data to the processing circuit 16 to execute various pulse sequences. Further, for example, the main control function 181 reads image data from the storage circuit 14 and outputs it to the display 13 in response to a request from the operator.

Here, the processing circuits 16 to 18 described above are implemented by, for example, processors. In this case, the processing functions of each processing circuit are stored in the storage circuit 14 in the form of a computer-executable program, for example. Each processing circuit reads and executes each program from the storage circuit 14, thereby realizing a function corresponding to each program. Here, each processing circuit may be composed of a plurality of processors, and each processor may implement each processing function by executing a program. Also, the processing functions of each processing circuit may be appropriately distributed or integrated in a single or a plurality of processing circuits. Also, although the single memory circuit 14 stores the programs corresponding to the respective processing functions here, a plurality of memory circuits may be distributed and arranged so that the processing circuits correspond to the individual memory circuits. A configuration for reading a program may be used.

The overall configuration of the MRI apparatus 100 according to this embodiment has been described above. Based on such a configuration, in this embodiment, the local coil 7 has a plurality of coil elements, and the MR signals generated from the subject S are received by each coil element. Note that the local coil 7 is an example of a receiving coil.

In addition, in this embodiment, the bed 5 has a port 52 to which the local coil 7 is connected, and the port 52 inputs MR signals received by a plurality of coil elements included in the local coil 7. It has multiple terminals.

FIG. 2 is a diagram showing a configuration example of the bed 5 according to this embodiment.

For example, as shown in FIG. 2, the bed 5 has a top plate 51, first to ninth ports 521 to 529, a bed base 53, and a retractor .

The first to ninth ports 521 to 529 are provided on the top plate 51 and connected to the local coils 7, respectively. For example, the first port 521, the second port 522, the eighth port 528, and the ninth port 529 are located at the end of the top plate 51 in the longitudinal direction near the pedestal 11 (left side in FIG. 2). is provided. The third to seventh ports 523 to 527 are provided at the end of the top plate 51 in the longitudinal direction farther from the pedestal 11 (right side in FIG. 2). Here, each port is capable of multi-channel reception, and is connected to the receiving circuit 9 via an individual transmission line.

The bed base 53 supports the tabletop 51 from below, and moves the tabletop 51 on which the subject S is placed to the inside of the bore B of the gantry 11 when the subject S is imaged. Here, the bed base 53 incorporates a movement mechanism for the top plate 51, and the movement mechanism moves the top plate 51 up and down, and longitudinally, back and forth, and left and right.

The retractor 54 is arranged between the top plate 51 and the bed base portion 53, and guides the movement of the plurality of transmission lines connected to the first to ninth ports 521 to 529 when the top plate 51 moves. . For example, the retractor 54 is a flexible cylindrical member that accommodates transmission lines connected to respective ports. The retractor 54 is bent inside a groove formed in the upper part of the bed base 53 along the movement direction of the top plate 51, and when the top plate 51 moves, the retractor 54 is bent. By transforming while changing, each transmission line is moved collectively.

FIG. 3 is a diagram showing an example of connection between the port 52 of the bed 5 and the local coil 7 according to this embodiment.

For example, as shown in FIG. 3, various local coils 7 prepared for each part of the subject S are connected to each port of the bed 5 . For example, the first port 521 is connected with the local coil 71 for the head, and the second port 522 is connected with the local coil 72 for the upper body. Also, for example, the third port 523 and the fourth port 524 are connected with the local coil 74 for the spine, and the fifth port 525 is connected with the local coil 73 for the lower body. Also, for example, general-purpose local coils 75 and 76 are connected to the sixth port 526 and the seventh port 527, respectively. Also, for example, linear coils 77 and 78 are connected to the eighth port 528 and the ninth port 529, respectively.

Here, each local coil has a plurality of coil elements 7a, and the MR signals generated from the subject S are received by each coil element 7a. Also, the linear coils 77 and 78 are composed of a single coil element 7a.

Each port of the bed 5 has a plurality of terminals for inputting MR signals received by a plurality of coil elements 7 a included in the local coil 7 . For example, the first port 521 has the same number of terminals as the number of coil elements 7a included in the local coil 71 for the head so that the local coil 71 for the head can be connected. Also, for example, the second through seventh ports 522-527 may be configured as upper torso local coils 72, lower torso local coils 73, spine local coils 74, or general purpose local coils 75 or 76, respectively. has the same number of terminals as the number of coil elements 7a that each local coil has so that each local coil can be connected. Also, for example, the eighth port 528 and the ninth port 529 each have one terminal so that the linear coils 77 or 78 can be connected.

In this embodiment, the port 52 of the bed 5 and the receiving circuit 9 are connected by a plurality of transmission paths for transmitting MR signals input from a plurality of terminals of the port 52 .

FIG. 4 is a diagram showing an example of a transmission line between the port 52 of the bed 5 and the receiving circuit 9 according to this embodiment.

For example, as shown in FIG. 4, the second port 522 of the bed 5 has 16 terminals T1 to T16. connected by Although the second port 522 will be described here as an example, the terminals of the other ports are similarly connected to the receiving circuit 9 via individual transmission paths.

Here, the plurality of transmission lines connected to the terminals T1 to T16 of the second port 522 pass through the retractor 54, the bed control board 15 provided on the bed 5, and the distribution board 8 provided on the pedestal 11. is connected to the receiving circuit 9 via the . As a result, the MR signals input from each terminal of each port of the bed 5 pass through the transmission path in the retractor 54 and gather in the bed control board 15, and then are transmitted to the receiving circuit 9 via the distribution board 8. be done.

Specifically, each transmission line includes a first cable C1 connecting between each terminal and the bed control board 15, and a second cable C2 connecting between the bed control board 15 and the distribution board 8. , and a third cable C3 connecting the distribution board 8 and the receiving circuit 9. FIG.

One end of the first cable C1 is connected to a terminal of the port 52, and the other end is connected to an input connector provided for each transmission line on the bed control board 15. . One end of the second cable C2 is connected to an output connector provided for each transmission line on the bed control board 15, and the other end is connected to the distribution board 8 for each transmission line. connected to the connector for the input. One end of the third cable C3 is connected to an output connector provided for each transmission line on the distribution board 8, and the other end is connected to an input connector provided on the receiving circuit 9. connected to the connector.

As described above, in the MRI apparatus 100 according to this embodiment, there are many long cables and many connectors between each port of the bed 5 and the receiving circuit 9 .

Normally, when an MRI apparatus having such a configuration is installed at an installation site such as a hospital, after all cables are connected, continuity confirmation is performed for all transmission lines in order to ensure quality. In addition, even after the MRI system has started operating, if a problem such as a disconnection of a connector or disconnection of a cable occurs, an investigation using a handy tester or the like will be conducted to identify the location of the problem. will be However, as mentioned above, when there are many long cables and many connectors, it is necessary to work by multiple workers to check the continuity of them, or until the location of the problem is identified. It may take time to start the operation of the MRI apparatus.

For this reason, the MRI apparatus 100 according to the present embodiment is configured such that it is possible to easily confirm continuity of the transmission line between the port 52 of the bed 5 and the receiving circuit 9 .

Specifically, in this embodiment, the processing circuitry 18 has a specific function 182 that identifies the state of continuity between the port 52 of the bed 5 and the receiving circuitry 9 . Note that the specific function 182 is an example of a specific unit.

More specifically, in this embodiment, the image generating function 171 generates an image for each of some of the plurality of transmission paths connecting between the port 52 of the bed 5 and the receiving circuit 9. . Note that the image generation function 171 is an example of an image generation unit.

The identification function 182 then identifies a transmission line in which disconnection has occurred among the plurality of transmission lines based on the image generated for each of the partial transmission lines.

Here, in this embodiment, the specific function 182 divides all or part of the transmission lines included in the plurality of transmission lines connecting between the port 52 of the bed 5 and the receiving circuit 9 into a plurality of groups. The images generated for each group are compared, and the darkest image is selected to narrow down the transmission paths, thereby specifying the transmission path in which the disconnection has occurred.

FIG. 5 is a diagram showing an example of transmission path identification by the image generation function 171 and the identification function 182 according to this embodiment.

For example, when starting the operation of the MRI apparatus, a reference image is picked up as a comparison target when a problem occurs, and stored in the MRI apparatus (for example, the storage circuit 14 or the like). For example, if the port 52 to be checked for conduction is connected to transmission lines ch1 to ch16 of 16 channels, an image generated using all the transmission lines ch1 to ch16 or a transmission Store multiple images, such as images generated for each road.

For example, when the port 52 to be checked for conduction is connected to 16 channels of transmission lines ch1 to ch16, first, the image generating function 171 generates an image based on the MR signal data of ch1 to ch16. Generate. A specific function 182 then compares the generated image to a reference image. Here, the reference image is, for example, an image generated based on MR signals acquired by connecting the local coil 7 to a normal port 52 in which disconnection has not occurred in advance.

Here, as shown in (a) of FIG. 5, when the images of ch1 to ch16 are darker than the reference image, the specific function 182 divides ch1 to ch16 into groups of ch1 to ch8 and ch9, for example. It is divided into a group of ~ch16. After that, the image generation function 171 generates an image based on the MR signal data of ch1 to ch8 and an image based on the MR signal data of ch9 to ch16. Then, the specific function 182 compares the image based on the MR signal data of ch1 to ch8 with the reference image based on the MR signal data of ch1 to ch8, and compares the image based on the MR signal data of ch9 to ch16 with the image based on the MR signal data of ch9 to ch16. are compared with a reference image based on the MR signal data, and the darker image as a result of comparison with the reference image is selected.

Here, for example, as shown in FIG. 5B, if the images of ch9 to ch16 are darker than the images of ch1 to ch8, the specific function 182 selects the images of ch9 to ch16. and further divides ch9 to ch16 into a group of ch9 to ch12 and a group of ch13 to ch16. After that, the image generating function 171 generates an image based on the MR signal data of ch9 to ch12 and an image based on the MR signal data of ch13 to ch16. Then, the specific function 182 compares the image based on the MR signal data of ch9 to ch12 with the reference image based on the MR signal data of ch9 to ch12, and the image based on the MR signal data of ch13 to ch16 and the image based on the MR signal data of ch13 to ch16. are compared with a reference image based on the MR signal data, and the darker image as a result of comparison with the reference image is selected.

Here, for example, as shown in (c) of FIG. 5, when the images of ch9 to ch12 are darker than the images of ch13 to ch16, the specific function 182 selects the images of ch9 to ch12. and further divides ch9-ch12 into a group of ch9-ch10 and a group of ch11-ch12. After that, the image generation function 171 generates an image based on the MR signal data of ch9-ch10 and an image based on the MR signal data of ch11-ch12. Then, the specific function 182 compares the image based on the MR signal data of ch9 to ch10 with the reference image based on the MR signal data of ch9 to ch10, and the image based on the MR signal data of ch11 to ch12 and the image based on the MR signal data of ch11 to ch12. are compared with a reference image based on the MR signal data, and the darker image as a result of comparison with the reference image is selected.

Here, for example, as shown in (d) of FIG. 5, when the images of ch11 to ch12 are darker than the images of ch9 to ch10, the specific function 182 selects the images of ch11 to ch12. , and further divides ch11 to ch12 into ch11 and ch12. After that, the image generation function 171 generates an image based on the ch11 MR signal data and an image based on the ch12 MR signal data. Then, the specifying function 182 compares the image based on the MR signal data of ch11 and the reference image based on the MR signal data of ch11, and the image based on the MR signal data of ch12 and the reference image based on the MR signal data of ch12. and select the darker image compared with the reference image.

Here, for example, as shown in (e) of FIG. 5, when the ch12 image is darker than the ch11 image, the specific function 182 selects the ch12 image to narrow down the transmission path, The last remaining channel, ch12, is identified as the transmission line in which disconnection has occurred.

After that, for example, the identification function 182 displays on the display 13 information indicating the transmission line identified as having a disconnection.

The image selection described here may be automatically performed by the MRI apparatus 100, or may be manually performed by an operator. In the case of automatic processing, for example, the specific function 182 determines the darker image by comparing the average brightness values of the pixels included in each image. In the case of manual operation, for example, the specific function 182 displays images to be compared on the display 13 and receives an operation of selecting a darker image from the operator.

Also, here, an example in which the specific function 182 divides the transmission lines into two groups has been described, but the number of groups into which the transmission lines are divided is not limited to two, and may be three or more. All transmission lines may be compared collectively. In that case, the specifying function 182 narrows down the transmission path by selecting the darkest image among the images generated for each group.

Returning to FIG. 1, in the present embodiment, the MRI apparatus 100 performs TDR measurement on the terminal of the port corresponding to the transmission line identified by the identifying function 182 as having a disconnection. It further has a TDR instrument 20 that performs Here, TDR instrument 20 is connected to processing circuitry 18 . Then, the identification function 182 identifies the disconnection position in the transmission line based on the result of the TDR measurement performed by the TDR measuring instrument 20 .

Here, the TDR measurement is a technique of applying a high-speed pulse signal or step signal to a transmission line to be measured and observing the waveform of the returned reflected wave. The waveform of the reflected wave obtained by TDR measurement indicates the change in the characteristic impedance of the transmission line. Therefore, by analyzing the shape of the waveform, it is possible to determine whether the transmission line is open (disconnected) or shorted (connected). It can be determined whether Further, by measuring the time until the waveform of the reflected wave is observed, the distance to the change point of the characteristic impedance can be calculated with high accuracy, so that an abnormal point in the transmission line can be identified.

FIG. 6 is a diagram showing an example of TDR measurement by the TDR measuring instrument 20 according to this embodiment.

For example, in the example shown in Figure 6, the port 52 of the couch 5 (middle of Figure 6) has 32 terminals, as indicated by the labels "A" through "R" and "1" through "14". is doing. Here, terminals "A" to "P" are terminals for inputting MR signals ("Sig1 to Sig16" in the table shown on the right side of FIG. 6) received by the coil element 7a of the local coil 7. FIG. In addition, the terminals “Q”, “R” and “1” to “14” are signals received or transmitted with devices other than the local coil 7 (“TX” in the table shown on the right side of FIG. 6, "ID1" to "ID8", etc.), and a terminal for grounding ("GND" in the table shown on the right side of FIG. 6).

In this case, the TDR measuring instrument 20 performs TDR measurement on the terminal connected to the transmission line identified by the identification function 182 as having a disconnection among the terminals “A” to “P”. conduct. At this time, the TDR measuring instrument 20 is connected to the terminal of the port 52 of the bed 5 via the transmission line 21 with the known characteristic impedance _Z0 .

Then, the identifying function 182 identifies the disconnection position in the transmission line identified as being disconnected based on the result of the TDR measurement performed by the TDR measuring instrument 20 . For example, the specific function 182 measures the time from when the pulse signal or step signal is applied by the TDR measuring instrument 20 to when the reflected wave is observed. Then, the identifying function 182 identifies the disconnection position by calculating the position where the reflection occurs from the measured time and the speed of the pulse signal or step signal.

After that, for example, the specifying function 182 displays on the display 13 information indicating the position of the disconnection in the transmission line in addition to the information indicating the transmission line identified as having the disconnection.

The terminals "Q", "R" and "1" to "14" can also be used to identify the defective portion.

Note that the TDR measurement described here may be automatically performed by the MRI apparatus 100, or may be manually performed by an operator. When it is performed automatically, for example, the TDR measuring instrument 20 is connected in advance to all the terminals of the target port 52 before the continuity check is performed, and the specific function 182 detects the transmission in which the disconnection has occurred. After identification, the TDR measurement for the transmission line is performed by controlling the TDR measuring instrument 20 . In the case of manual operation, for example, after the specified function 182 specifies the transmission line in which the disconnection has occurred, the worker connects the TDR measuring instrument 20 to the terminal corresponding to the transmission line, and the TDR Measurements are taken.

Returning to FIG. 1, in this embodiment, the processing circuit 18 has a switching function of switching a broken transmission line to a non-broken transmission line based on the broken line position specified by the specifying function 182. 183 further. Note that the switching function 183 is an example of a switching unit.

FIG. 7 is a diagram showing an example of switching of transmission paths by the switching function 183 according to this embodiment.

For example, in the example shown in FIG. 7, the bed control board 15 does not disconnect each of the plurality of transmission lines connecting between the port 52 of the bed 5 and the receiving circuit 9. It has a switching circuit 151 for switching to another transmission line. Here, the other transmission line to be switched to is, for example, a transmission line connected to a terminal of another port 25 different from the port 52 including the terminal connected to the transmission line to be switched. Alternatively, the other transmission line to be switched to may be, for example, a transmission line connected to an unused terminal among terminals in the same port 52 as the terminal connected to the transmission line to be switched. . Although the switching circuit 151 provided in the first transmission channel ch, which is one of the plurality of transmission channels, will be described here, the switching circuits 151 connected to other transmission channels have the same configuration. have.

For example, the switching circuit 151 provided in the first transmission line ch includes a first fuse 1511 inserted in the first transmission line ch1 and a second fuse 1511 inserted in another transmission line chx as a switching destination. and a fuse 1512 . Further, the switching circuit 151 includes a first switch 1513 provided between the input terminal of the first fuse 1511 and the input terminal of the second fuse 1512, and the output terminal of the first fuse 1511 and the second switch. It has a second switch 1514 provided between the output end of the fuse 1512 and a third switch 1515 provided between one end of the first switch 1513 and one end of the second switch 1514 . ing.

Here, when there is no disconnection in the first transmission line ch1, the switching circuit 151 causes the first fuse 1511 and the second fuse 1512 to conduct and the first The switch 1513, the second switch 1514, and the third switch 1515 are turned off. As a result, the path ahead of the bed control board 15 in the first transmission line ch1 is connected to the path ahead of the bed control board 15 in the first transmission line ch1 via the first fuse 1511 .

Then, for example, the specifying function 182 specifies that the first transmission line ch1 is broken, and the position of the break in the first transmission line ch1 specified by the specifying function 182 is earlier than the bed control board 15. , the switching function 183 switches the state of the switching circuit 151 so that the first transmission line ch1 is connected to the other transmission line chx.

Specifically, the switching function 183 disconnects the first fuse 1511 and the second fuse 1512 and turns on the first switch 1513 and the third switch 1515, as shown in the lower part of FIG. . As a result, the path on the front side of the bed control board 15 in the first transmission line ch1 passes through the first switch 1513 and the third switch 1515, and the path ahead of the bed control board 15 in the other transmission line chx. connected to As a result, the MR signal input from the terminal of the port 52 corresponding to the first transmission line ch1 is transmitted to the receiving circuit 9 via the other transmission line chx.

The switching of the transmission line described here may be automatically performed by the MRI apparatus 100, or may be manually performed by an operator. When it is performed automatically, for example, the transmission line is switched by controlling the switching function 183 after the specifying function 182 specifies the disconnection position in the transmission line. In the case of manual operation, for example, after the specified function 182 specifies the broken transmission line, the switching function 183 accepts an operator's operation to specify the transmission line to be switched. Switch the transmission line.

FIG. 8 is a flow chart showing the flow of the conduction confirmation method according to this embodiment.

The conduction confirmation method described here is performed, for example, after the cables are connected when the MRI apparatus 100 is installed. Also, the conduction confirmation method described here is performed as one of the inspection tasks that are periodically performed after the MRI apparatus 100 starts operating, for example.

For example, as shown in FIG. 8, in the conduction confirmation method according to the present embodiment, first, the main control function 181 receives a signal from an operator while the local coil 7 is connected to the port 52 to be confirmed for conduction. MR signal data is acquired according to the start instruction (step S101).

At this time, for example, the main control function 181 acquires MR signal data by executing a preset pulse sequence for continuity confirmation. Here, the collected MR signal data are stored in the storage circuit 14 for each transmission path connected to the port 52 .

After that, the image generation function 171 reads the MR signal data of all the transmission lines from the storage circuit 14 and generates an image based on the read MR signals (step S102).

Subsequently, the specifying function 182 compares the image generated by the image generating function 171 with the reference image (step S103). Here, if the generated image is the same as the reference image (step S104, No), the specific function 182 terminates the conduction confirmation process.

On the other hand, if the generated image is darker than the reference image (step S104, Yes), the specific function 182 sets all the transmission lines as the target transmission lines for operation check (step S105), and selects a plurality of target transmission lines. (step S106).

After that, the image generation function 171 generates an image for each group based on the MR signal data (step S107).

Subsequently, the identification function 182 compares the images generated by the image generation function 171 (step S108) and selects the darkest image (step S109). Then, the specifying function 182 sets the transmission line of the selected image as the transmission line to be checked for continuity (step S110).

If a plurality of target transmission lines are set (step S111, No), the specifying function 182 again divides the target transmission lines into a plurality of groups (returns to step S106), The above-described processing is repeated until there is only one target transmission line (steps S107 to S110).

Then, when there is only one target transmission line (step S111, Yes), the specifying function 182 specifies the target transmission line set at that time as the transmission line in which disconnection has occurred (step S112).

Thereafter, the TDR measuring instrument 20 performs TDR measurement on the terminal of the port corresponding to the transmission line identified by the identifying function 182 as having a disconnection (step S113). Then, the identification function 182 identifies the disconnection position in the transmission line based on the result of the TDR measurement performed by the TDR measuring device 20 (step S114).

After that, the switching function 183 switches the transmission line identified as having a disconnection to a transmission line having no disconnection based on the disconnection position identified by the identifying function 182 (step S115).

Here, an example of narrowing down a plurality of transmission lines in stages while dividing them into groups has been described, but the embodiment is not limited to this. For example, the image generation function 171 does not generate an image for each transmission line group, but for the number of transmission lines connected to the port 52 to be checked for continuity, that is, for each transmission line. You may In this case, the identification function 182 compares the images generated for each transmission line, selects the darkest image, and identifies the transmission line of the selected image as the transmission line in which disconnection has occurred.

As described above, in this embodiment, the image generation function 171 generates an image for each of some of the plurality of transmission paths. Then, the identification function 182 identifies a transmission line in which disconnection has occurred among the plurality of transmission lines based on the image generated for each part of the transmission lines. According to such a configuration, by generating an image from the MR signals collected for each transmission line, it is possible to identify the transmission line in which disconnection has occurred. be able to. In addition, the connection state of the transmission line is simplified, making it possible to improve work efficiency. Therefore, according to the present embodiment, it is possible to easily confirm continuity of the transmission line between the port 52 of the bed 5 and the receiving circuit 9 .

Further, in this embodiment, the specifying function 182 divides all or part of the transmission paths included in the plurality of transmission paths into a plurality of groups, compares the images generated for each group, and compares the darkest images. While narrowing down the transmission lines by selecting images, the transmission line in which the disconnection has occurred is specified. According to such a configuration, compared with the case of generating an image for each transmission line, the number of times of image generation can be reduced, and the transmission line in which the disconnection has occurred can be efficiently identified in a short time. can be done.

Further, in the present embodiment, the identifying function 182 determines, for a transmission line identified as having a disconnection, based on the results of TDR measurement performed on the port terminal corresponding to the transmission line, Identify the disconnection position in the road. According to such a configuration, it is possible to accurately identify the disconnection position in the transmission line by using the TDR measurement.

Further, in the present embodiment, the switching function 183 switches a disconnected transmission line to a non-disconnected transmission line based on the disconnection position specified by the specifying function 182 . According to such a configuration, even if there is a transmission line with disconnection, the port connected to the transmission line can be used continuously.

In addition, the term "processor" used in the above description is, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or an application specific integrated circuit (ASIC), a programmable logic device (eg, Simple Programmable Logic Device (SPLD), Complex Programmable Logic Device (CPLD), and Field Programmable Gate Array (FPGA)). Instead of storing the program in the memory circuit, the program may be directly incorporated in the circuit of the processor. In this case, the processor implements its functions by reading and executing the program embedded in the circuit. Further, each processor of the present embodiment is not limited to being configured as a single circuit for each processor, but may be configured as one processor by combining a plurality of independent circuits to realize its function. good. Furthermore, a plurality of components in FIG. 1 may be integrated into one processor to realize its functions.

Here, the program to be executed by the processor is provided by being pre-installed in, for example, a ROM (Read Only Memory), a storage circuit, or the like. This program is a file in a format that can be installed in these devices or a file in a format that can be installed on a computer such as CD (Compact Disk)-ROM, FD (Flexible Disk), CD-R (Recordable), DVD (Digital Versatile Disk), etc. may be recorded on a readable storage medium and provided. Also, this program may be provided or distributed by being stored on a computer connected to a network such as the Internet and downloaded via the network. For example, this program is composed of modules including each functional unit described above. As actual hardware, the CPU reads out a program from a storage medium such as a ROM and executes it, so that each module is loaded onto the main storage device and generated on the main storage device.

According to at least one embodiment described above, it is possible to easily confirm continuity of the transmission line between the port of the bed and the receiving circuit.

While several embodiments of the invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, as well as the scope of the invention described in the claims and equivalents thereof.

100 magnetic resonance imaging (MRI) device 7 local coil 5 bed 9 receiving circuit 17 processing circuit 171 image generation function 18 processing circuit 182 specific function 183 switching function

Claims (5)

a receiving coil having a plurality of coil elements, each coil element receiving a magnetic resonance signal generated from a subject;
a bed having a port to which the receiving coil is connected and on which the subject is placed;
a receiving circuit that generates magnetic resonance signal data based on the magnetic resonance signal input from the port;
an image generator that generates an image based on the magnetic resonance signal data;
a specifying unit that specifies a conduction state between the port and the receiving circuit;
The port has a plurality of terminals for inputting magnetic resonance signals received by the plurality of coil elements,
The port and the receiving circuit are connected by a plurality of transmission paths for transmitting magnetic resonance signals input from the plurality of terminals,
The image generating unit generates an image for each of some of the plurality of transmission paths,
The identifying unit identifies a transmission line in which disconnection has occurred among the plurality of transmission lines based on the image generated for each of the partial transmission lines.
Magnetic resonance imaging equipment. The specifying unit divides all or part of the transmission paths included in the plurality of transmission paths into a plurality of groups, compares images generated for each group, and selects the darkest image. identifying the transmission line in which the disconnection occurs while narrowing down the transmission lines;
The magnetic resonance imaging apparatus according to claim 1. For the transmission path identified as having the disconnection, the identification unit determines the transmission to identify the position of the disconnection in the road,
3. The magnetic resonance imaging apparatus according to claim 1 or 2. further comprising a switching unit that switches the broken transmission line to a non-broken transmission line based on the position of the broken line identified by the identifying unit;
4. A magnetic resonance imaging apparatus according to claim 3. a receiving coil having a plurality of coil elements, each coil element receiving a magnetic resonance signal generated from a subject;
a bed having a port to which the receiving coil is connected and on which the subject is placed;
a receiving circuit that generates magnetic resonance signal data based on the magnetic resonance signal input from the port ;
The port has a plurality of terminals for inputting magnetic resonance signals received by the plurality of coil elements,
In a magnetic resonance imaging apparatus, wherein the port and the receiving circuit are connected by a plurality of transmission paths for transmitting magnetic resonance signals input from the plurality of terminals,
A continuity confirmation method for identifying a continuity state between the port and the receiving circuit,
generating an image for each of some of the plurality of transmission channels based on the magnetic resonance signal data;
and identifying a transmission line in which disconnection has occurred among the plurality of transmission lines based on the image generated for each of the partial transmission lines.

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