Magnetic resonance imaging apparatus and imaging management method

Abstract

An object of the present application is to assist highly efficient inspection. A magnetic resonance imaging apparatus according to an embodiment includes a calculation section and an input restriction section. The calculation section calculates a limit imaging condition based on one or more imaging parameters used to determine an imaging condition, the limit imaging condition becoming a limit with respect to a heat input to a superconducting magnet. The input restriction section restricts an input range of the imaging parameters from an operator based on the limit imaging condition.

Description

[0001] Citation of relevant applications

[0002] This application is based on and asserts the priority of Japanese Patent Application No. 2020-186611, filed on November 9, 2020, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] The embodiments of the present invention generally relate to magnetic resonance imaging apparatus and camera management method. Background Technology

[0004] In superconducting magnetic resonance imaging (MRI) devices, helium is used as a coolant for the superconducting coils. However, due to the soaring price of helium in recent years, the lifespan cost of MRI devices has been under pressure. Therefore, it is desirable to use a low-capacity coolant that minimizes the amount of helium used.

[0005] With the increasing focus on low-capacity refrigerants in recent years, the following phenomenon needs to be considered: the phenomenon of temperature rise within the superconducting magnet (GCIH) caused by the application of a gradient magnetic field during imaging, which induces a current in the superconducting coil. In other words, in MRI devices with ample helium capacity and sufficient refrigerant, the heat generated by the temperature rise in the superconducting coil is likely to be absorbed through refrigerant evaporation. However, with low-capacity refrigerants, the amount of refrigerant is insufficient to cope with the rapid increase in GCIH caused by imaging, increasing the likelihood of quenching due to heat intrusion from the outside.

[0006] Therefore, existing methods include predicting actions related to magnet quenching for each camera, and stopping before actual recording if the risk of quenching is high. However, since determining whether recording is possible during the recording phase after setting the recording conditions, the recording conditions need to be reset if it is determined that recording is not possible. Therefore, it may also be necessary to change the conditions and re-record, or wait until recording is possible, resulting in inefficient recording.

[0007] [Existing technical documents]

[0008] [Patent Document 1] US Patent No. 8058873 Specification Summary of the Invention

[0009] [The technical problem that the invention aims to solve]

[0010] One of the technical problems to be solved by the embodiments disclosed in this specification and accompanying drawings is to assist in efficient inspection. However, the technical problems to be solved by the embodiments disclosed in this specification and accompanying drawings are not limited to the above-mentioned technical problems. Technical problems corresponding to the effects of the various structures shown in the embodiments described below can also be identified as other technical problems.

[0011] The magnetic resonance imaging apparatus of this embodiment includes a calculation unit and an input limiting unit. The calculation unit calculates limiting imaging conditions based on one or more imaging parameters used to determine imaging conditions; these limiting imaging conditions constitute the permissible limit regarding thermal input to the superconducting magnet. The input limiting unit, based on these limiting imaging conditions, limits the input range of imaging parameters from the operator.

[0012] [The effects of the invention]

[0013] The purpose of this invention is to assist in efficient inspection. Attached Figure Description

[0014] Figure 1 This is a conceptual diagram illustrating the MRI apparatus of this embodiment.

[0015] Figure 2 This is a flowchart illustrating the camera management process of the MRI device in this embodiment.

[0016] Figure 3 This is a flowchart illustrating the detailed process of estimating the extreme imaging conditions in this embodiment.

[0017] Figure 4 This is a conceptual diagram illustrating a calculation example of the amount of heat required to generate the heat generation database in this embodiment.

[0018] Figure 5 This is a diagram illustrating an example of the transfer function in this embodiment.

[0019] Figure 6 This is a diagram showing an example of a user interface screen in this embodiment.

[0020] Figure 7 This is a diagram showing a first example of a user interface related to camera parameters.

[0021] Figure 8 This is a diagram showing a first example of a user interface related to camera parameters.

[0022] Explanation of reference numerals in the attached figures

[0023] 1 MRI device

[0024] 2 Magnet Management Unit

[0025] 20 Temperature Measurement Circuit

[0026] 21 Sensor Control Unit

[0027] 22 Computing Department

[0028] 61 MR images

[0029] Table 61

[0030] 63 Settings Window

[0031] 71 Slider

[0032] 72 cursors

[0033] 81 List Window

[0034] 101 Static Magnetic Field Magnet

[0035] 103 Gradient Magnetic Field Coil

[0036] 105 Gradient Magnetic Field Power Supply

[0037] 107 Examination Beds

[0038] 109 Examination Bed Control Circuit

[0039] 111 holes

[0040] 113 Transmitting Circuit

[0041] 115 Transmitting Coil

[0042] 117 Receiving Coil

[0043] 119 Receiver Circuit

[0044] 121 Sequence Control Circuit

[0045] 123 bus

[0046] 125 interface

[0047] 127 monitor

[0048] 129 Storage devices

[0049] 131 Processing Circuit

[0050] 1311 System Control Functions

[0051] 1313 Image generation function

[0052] 1315 Calculation Function

[0053] 1317 Input restriction function

[0054] 1319 User Interface Functions

[0055] 1321 Notification Function

[0056] 1323 Estimation function

[0057] 1325 Judgment Function Detailed Implementation

[0058] Hereinafter, the magnetic resonance imaging apparatus (MRI apparatus) and image management method of this embodiment will be described with reference to the accompanying drawings. In the following embodiments, the parts marked with the same reference numerals will be performed in the same manner, and repeated descriptions will be omitted where appropriate.

[0059] Figure 1 This is a conceptual diagram illustrating the MRI apparatus of this embodiment.

[0060] like Figure 1 As shown, the MRI device 1 includes a static magnetic field magnet 101, a magnet management unit 2, a gradient magnetic field coil 103, a gradient magnetic field power supply 105, an examination table 107, an examination table control circuit 109, a transmitting circuit 113, a transmitting coil 115, a receiving coil 117, a receiving circuit 119, a sequence control circuit 121, a bus 123, an interface 125, a display 127, a storage device 129, and a processing circuit 131. Alternatively, the MRI device 1 may also have a hollow cylindrical shim coil between the static magnetic field magnet 101 and the gradient magnetic field coil 103.

[0061] The static magnetic field magnet 101 is a magnet formed in a hollow, generally cylindrical shape. However, the static magnetic field magnet 101 is not limited to a generally cylindrical shape and can also be configured in an open shape. The static magnetic field magnet 101 generates a uniform static magnetic field within its internal space. In this embodiment, a superconducting magnet with a superconducting coil is assumed to be used as the static magnetic field magnet 101.

[0062] The gradient magnetic field coil 103 is a coil formed in the shape of a hollow cylinder. The gradient magnetic field coil 103 is disposed inside the static magnetic field magnet 101. The gradient magnetic field coil 103 is formed by combining three coils corresponding to the mutually orthogonal X, Y, and Z axes. The Z-axis direction is the same as the direction of the static magnetic field. Furthermore, the Y-axis direction is vertical, and the X-axis direction is perpendicular to both the Z and Y axes. The three coils in the gradient magnetic field coil 103 receive current from the gradient magnetic field power supply 105, generating a gradient magnetic field whose magnetic field strength varies along the X, Y, and Z axes.

[0063] The gradient magnetic fields along the X, Y, and Z axes generated by the gradient magnetic field coil 103 form, for example, a gradient magnetic field for frequency encoding (also called a readout gradient magnetic field), a gradient magnetic field for phase encoding, and a gradient magnetic field for slice selection. The gradient magnetic field for frequency encoding is used to change the frequency of the MR signal according to its spatial location. The gradient magnetic field for phase encoding is used to change the phase of the MR signal according to its spatial location. The gradient magnetic field for slice selection is used to determine the imaging cross-section.

[0064] The gradient magnetic field power supply 105 is a power supply device that supplies current to the gradient magnetic field coil 103 under the control of the sequence control circuit 121.

[0065] The examination table 107 is a device equipped with a top plate 1071 for placing the subject P. Under the control of the examination table control circuit 109, the examination table 107 inserts the top plate 1071 on which the subject P is placed into the hole 111. The examination table 107 is, for example, arranged in an examination room equipped with an MRI device 1, with its length direction parallel to the central axis of the static magnetic field magnet 101.

[0066] The examination bed control circuit 109 is a circuit that controls the examination bed 107. It drives the examination bed 107 by means of instructions from the operator via the interface 125, thereby causing the top plate 1071 to move along the long side and in the vertical direction.

[0067] The transmitting coil 115 is an RF coil disposed inside the gradient magnetic field coil 103. The transmitting coil 115 receives RF (Radio Frequency) pulses from the transmitting circuit 113 and generates a transmitted RF wave equivalent to a high-frequency magnetic field. The transmitting coil 115 is, for example, a whole-body coil. A whole-body coil can also be used as a transmitting / receiving coil. A cylindrical RF shield is provided between the whole-body coil and the gradient magnetic field coil 103 to magnetically separate these coils.

[0068] The transmitting circuit 113 supplies RF pulses corresponding to the Larmor frequency to the transmitting coil 115 under the control of the sequence control circuit 121.

[0069] The receiving coil 117 is an RF coil disposed inside the gradient magnetic field coil 103. The receiving coil 117 receives the MR signal emitted from the subject P by a high-frequency magnetic field. The receiving coil 117 outputs the received MR signal to the receiving circuit 119. The receiving coil 117 is, for example, a coil array having one or more coil elements, typically multiple coil elements. The receiving coil 117 is, for example, a phased array coil.

[0070] The receiving circuit 119, under the control of the sequence control circuit 121, generates digitized complex data, i.e., a digital MR signal, based on the MR signal output from the receiving coil 117. Specifically, the receiving circuit 119 performs various signal processing operations on the MR signal output from the receiving coil 117, and then performs analog-to-digital (A / D) conversion on the processed data. The receiving circuit 119 samples the A / D converted data. Thus, the receiving circuit 119 generates a digital MR signal (hereinafter referred to as MR data). The receiving circuit 119 outputs the generated MR data to the sequence control circuit 121.

[0071] The sequence control circuit 121 controls the gradient magnetic field power supply 105, the transmitting circuit 113, and the receiving circuit 119, etc., to image the subject P according to the inspection protocol output from the processing circuit 131. The inspection protocol has various pulse sequences (also called imaging sequences) corresponding to the inspection. The inspection protocol defines the magnitude of the current supplied by the gradient magnetic field power supply 105 to the gradient magnetic field coil 103, the timing of the current supplied by the gradient magnetic field power supply 105 to the gradient magnetic field coil 103, the magnitude of the RF pulse supplied by the transmitting circuit 113 to the transmitting coil 115, the timing of the RF pulse supplied by the transmitting circuit 113 to the transmitting coil 115, and the timing of the MR signal received by the receiving coil 117, etc.

[0072] Bus 123 is a data transmission path between interface 125, display 127, storage device 129, and processing circuit 131. Bus 123 can be appropriately connected to various biological signal detectors, external storage devices, and various modalities via networks or the like. For example, an electrocardiograph (not shown) is connected to the bus as a biological signal detector.

[0073] Interface 125 has circuitry for receiving various instructions and information inputs from the operator. Interface 125 may include circuitry related to pointing devices such as a mouse or input devices such as a keyboard. However, the circuitry of interface 125 is not limited to circuitry related to physical operating components such as a mouse or keyboard. For example, interface 125 may also include processing circuitry for receiving electrical signals corresponding to input operations from external input devices separately installed from the MRI device 1, and outputting the received electrical signals to various circuits.

[0074] Under the control of the system control function 1311 in the processing circuit 131, the display 127 displays various magnetic resonance images (MR images) generated by the image generation function 1313, as well as various information related to imaging and image processing. The display 127 is, for example, a CRT display, a liquid crystal display, an organic EL display, an LED display, a plasma display, or any other display, monitor, or other display device known in the art.

[0075] Storage device 129 stores MR data filled into the k-space via image generation function 1313, image data generated by image generation function 1313, etc. Storage device 129 stores imaging conditions including various inspection protocols and multiple imaging parameters specifying the inspection protocols. Storage device 129 stores programs corresponding to various functions executed by processing circuit 131. Storage device 129 can be, for example, a semiconductor memory element such as RAM (Random Access Memory), flash memory, a hard disk drive, a solid state drive, an optical disc, etc. Alternatively, storage device 129 can also be a drive device for reading and writing various information to removable storage media such as CD-ROM drives, DVD drives, and flash memory.

[0076] The magnet management unit 2 includes a temperature measuring circuit 20.

[0077] The temperature measuring circuit 20 measures the temperature of one or more superconducting coils of the static magnetic field magnet 101 that generates the static magnetic field using a temperature sensor.

[0078] The processing circuit 131 has a processor (not shown), ROM (Read-Only Memory) or RAM, or other memory as hardware resources to uniformly control the MRI device 1. The processing circuit 131 includes system control functions 1311, image generation functions 1313, calculation functions 1315, input restriction functions 1317, user interface functions 1319, prompting functions 1321, estimation functions 1323, and judgment functions 1325.

[0079] The various functions of the processing circuit 131 are stored in the storage device 129 in the form of computer-executable programs. The processing circuit 131 is a processor that implements the functions corresponding to each program by reading from the storage device 129 and executing the programs corresponding to these various functions. In other words, the processing circuit 131, having read the state of each program, has... Figure 1 The processing circuit 131 contains multiple functions, etc.

[0080] In addition, Figure 1In this paper, the various functions are described as being implemented by a single processing circuit 131. However, the processing circuit 131 can also be composed of multiple independent processors, with each processor executing a program to implement the function. In other words, the various functions described above are configured as programs, which can be either executed by a single processing circuit or have specific functions installed in dedicated independent program execution circuits.

[0081] Additionally, the term "processor" used in the above description refers to circuits such as CPU (Central Processing Unit), GPU (Graphics Processing Unit), or Application Specific Integrated Circuit (ASIC), programmable logic device (e.g., Simple Programmable Logic Device (SPLD), Complex Programmable Logic Device (CPLD), and Field Programmable Gate Array (FPGA)).

[0082] The processor performs various functions by reading and executing the program stored in the storage device 129. Alternatively, instead of storing the program in the storage device 129, the program can be directly programmed into the processor's circuitry. In this case, the processor performs the functions by reading and executing the program programmed into the circuitry. Furthermore, the examination bed control circuit 109, the transmitting circuit 113, the receiving circuit 119, the sequence control circuit 121, etc., are also composed of the aforementioned electronic circuitry such as the processor.

[0083] Processing circuit 131 controls MRI device 1 via system control function 1311. Specifically, processing circuit 131 reads the system control program stored in storage device 129 and expands it in memory, controlling each circuit of MRI device 1 according to the expanded system control program. For example, processing circuit 131 reads the examination protocol from storage device 129 based on the imaging conditions input by the operator via interface 125 through system control function 1311. Alternatively, processing circuit 131 may also generate an examination protocol based on the imaging conditions. Processing circuit 131 sends the examination protocol to sequence control circuit 121 to control the imaging of subject P.

[0084] The processing circuit 131 is controlled by the system control function 1311 to apply excitation pulses according to the excitation pulse sequence and to apply a gradient magnetic field. After executing the excitation pulse sequence through the system control function 1311, the processing circuit 131 collects MR signals from the subject P according to various data collection pulse sequences, i.e., data collection sequences, and generates MR data.

[0085] Processing circuit 131 fills MR data along the readout direction in k-space according to the strength of the readout gradient magnetic field using image generation function 1313. Processing circuit 131 performs a Fourier transform on the MR data filled in k-space, thereby generating an MR image. For example, processing circuit 131 can generate an absolute value (magnitude) image from complex MR data. Furthermore, processing circuit 131 can generate a phase image using the real and imaginary data in complex MR data. Processing circuit 131 outputs MR images, including the absolute value image and the phase image, to display 127 and storage device 129.

[0086] The processing circuit 131 calculates the permissible limit of heat for the superconducting magnet based on one or more imaging parameters used to determine the imaging conditions through the calculation function 1315.

[0087] The processing circuit 131 limits the input range of camera parameters from the operator based on camera limit conditions through an input limiting function.

[0088] The processing circuit 131 accepts input of one or more camera parameters for determining camera conditions through the user interface function 1319.

[0089] The processing circuit 131 prompts the operator with at least one of the extreme camera conditions and the transformed value obtained by transforming the extreme camera conditions into a risk-related value through the prompting function 1321.

[0090] Processing circuit 131 estimates, through estimation function 1323, characteristic quantities related to the thermal input of the static magnetic field magnet under imaging conditions.

[0091] The processing circuit 131 determines whether the feature quantity meets the extreme imaging conditions through the judgment function 1325.

[0092] Next, refer to Figure 2 The flowchart describes the image management process of the MRI device 1 in this embodiment. Figure 2 The process shown in the flowchart is assumed, for example, to be performed when determining the shooting conditions for a single shooting sequence.

[0093] In step S201, the processing circuit 131 calculates the limiting camera conditions for the camera parameters that can be set for the camera sequence using the calculation function 1315. For the calculation method of the limiting camera conditions, refer to... Figures 3 to 5 To be described later.

[0094] In step S202, the processing circuit 131 obtains the camera parameters related to the camera conditions, which are obtained by the operator through user interface function 1319, based on the user interface screen. At this time, the processing circuit 131, through input restriction function 1317, limits the input range of the camera parameters from the operator in the user interface screen based on extreme camera conditions. Specifically, for example, the input restriction function 1317 sets an upper or lower limit value for the camera parameters, restricting the input to values ​​larger than the upper limit and smaller than the lower limit, respectively.

[0095] In step S203, processing circuit 131 estimates a heat-related characteristic quantity through estimation function 1323. This heat is assumed to include the heat generated in the superconducting magnet under the imaging conditions obtained in step S202. The characteristic quantity includes the heat generated in the superconducting coil and its temperature change, as well as the amount of heat input to the superconducting coil, when the subject is imaged. Specifically, for example, a value associated with the risk of quenching failure after imaging can be estimated as a characteristic quantity.

[0096] In step S204, the processing circuit 131 determines, through the determination function 1325, whether the feature quantity estimated in step S203 meets the limit imaging conditions. If the feature quantity meets the limit imaging conditions, the process proceeds to step S207; otherwise, it proceeds to step S205.

[0097] In step S205, the processing circuit 131 determines, via the determination function 1325, whether to skip the current camera shot and proceed to the next camera shot. For example, if the operator provides input related to resetting the camera shot conditions, it determines that the conditions have changed and proceeds to step S206. On the other hand, if the operator receives an instruction to cancel the camera shot, it determines that the camera shot will not be performed, that is, it skips the current camera shot and proceeds to the next camera shot, thus ending the processing.

[0098] In step S206, the processing circuit 131 changes the camera conditions via the user interface function 1319. For example, the operator receives input related to the change of camera conditions. Alternatively, the processing circuit 131 can automatically set alternative camera conditions. Then, it returns to step S201 and repeats the same process.

[0099] In step S207, the processing circuit 131 determines the camera conditions obtained in step S202 because the camera conditions obtained in step S202 meet the limit camera conditions and there is no risk in the camera operation based on these camera conditions, for example, no loss of overshoot will occur.

[0100] In step S208, the MRI device 1 performs imaging based on the imaging conditions determined in step S205.

[0101] Furthermore, in step S202, the processing circuit 131 may, through the prompting function 1321, prompt the operator with at least one of the extreme imaging conditions and a transformed value obtained by converting the extreme imaging conditions into a risk-related value. For example, the extreme imaging condition may be displayed as the critical temperature at which the superconducting magnet will quench, and the transformed value may be displayed as the remaining temperature from the current temperature of the superconducting magnet to the critical temperature, or the percentage of the temperature at which the critical temperature will be reached. Thus, the operator can use this as a reference when inputting imaging conditions.

[0102] Alternatively, in step S202, the processing circuit 131 can also preset the camera conditions that meet the extreme camera conditions. Alternatively, the operator can confirm the preset camera parameters, and input them if necessary, such as corrections or additions. This saves input time by eliminating the need to input all camera parameters related to the camera conditions from the beginning.

[0103] Furthermore, steps S203 to S206 can be performed or omitted. That is, the imaging conditions obtained in step S202 are within the range of limit imaging conditions, so the imaging in step S208 can be performed after the processing in step S202.

[0104] Next, refer to Figure 3 The flowchart below explains the details of the estimation process for extreme camera conditions in step S201.

[0105] In step S301, the processing circuit 131 calculates the amount of heat that can be heated using the calculation function 1315. Specifically, it calculates the amount of heat that can be heated without quenching by using information such as the current temperature of the static magnetic field magnet, the thermal equilibrium temperature of the structure wound with the superconducting wire, the critical temperature at which the static magnetic field magnet loses quench, the heat capacity of the coil portion that generates the main magnetic field of the superconducting wire, the cooling capacity of the refrigerator, and the pressure of the refrigerant when using a refrigerant such as liquid helium.

[0106] In step S302, the processing circuit 131 calculates the limit values ​​of the imaging conditions, i.e., the extreme imaging conditions, based on the calorific value database using the calculation function 1315. The calorific value database is a database that stores the correspondence between imaging conditions and heat generation, for example, stored in the storage device 129 or an external storage device. Specifically, through the calculation function 1315, the processing circuit 131 calculates the limit values ​​of heat-related imaging conditions, such as TR (Repetition Time), slice thickness, and spatial resolution, based on the calorific value database, the heat that can be heated calculated in step S301, and information including the type of imaging and cross-sectional direction, as the extreme imaging conditions.

[0107] Next, refer to Figure 4 An example of calculating the calorific value required to generate the calorific value database is provided.

[0108] In MRI imaging, there are various imaging conditions, such as the types of imaging sequences, cross-sectional orientation, TR (transverse velocity), and slice thickness, which are considered according to the imaging purpose. On the other hand, since actual calorific value measurement takes a lot of time, it is impractical to actually measure calorific value under all assumed imaging conditions.

[0109] Therefore, in Figure 4 In step S401 shown, based on the type of camera sequence, the cross-sectional direction in the camera, and camera conditions such as TR and ST, three tilted magnetic field waveforms are generated relative to each direction of Gx, Gy, and Gz.

[0110] In step S402, time series data of three tilted magnetic field waveforms are obtained when the camera is captured along the camera sequence.

[0111] In step S403, Fourier transforms are performed on the time series data of the tilted magnetic field waveform to calculate the frequency component data of each tilted magnetic field waveform.

[0112] In step S404, the heat generation of the tilted magnetic field waveform is estimated based on the frequency component data of the gradient magnetic field waveform calculated in step S403, using a transfer function related to the heat generation relative to the pre-measured gradient magnetic field waveforms of Gx, Gy, and Gz. By storing the above results in a heat generation database, a heat generation database can be generated, and the heat generation corresponding to the imaging conditions can be calculated.

[0113] Next, refer to Figure 5 An example of the transfer function used in the calculation of heat generation in step S404 will be explained.

[0114] Figure 5This is a graph representing the amount of heat generated relative to the frequency components of the three gradient magnetic fields, Gx, Gy, and Gz. The vertical axis represents the amount of heat generated, and the horizontal axis represents the frequency components.

[0115] Regarding the transfer function, for example, the relationship between the heat generated when heating the superconductor and its support structure with respect to the frequency components, when a gradient magnetic field is pre-applied during the installation of MRI device 1 or when MRI device 1 is manufactured, is measured in the form of a transfer function using three gradient magnetic fields. To calculate the transfer function, the amount of heat generated relative to the assumed imaging conditions in actual imaging is calculated beforehand.

[0116] Furthermore, if the types of imaging sequences are the same, representative imaging conditions such as TR, number of slices, and spatial resolution have a simple correlation with heat generation. Therefore, by determining baseline imaging conditions for each imaging sequence and actually measuring the heat generation during imaging under those conditions in advance, it is possible to determine the limiting imaging conditions under which imaging can be performed without the risk of quenching by comparing them with the baseline imaging conditions.

[0117] Next, refer to Figures 6 to 8 An example of a user interface screen that is also used in user interface function 1319 will be explained.

[0118] Figure 6 It is a user interface screen that includes MR images 61 captured along the camera protocol, a table 62 indicating the types and order of camera sequences, and a setting window 63 for setting camera parameters.

[0119] in addition, Figure 6 The state of the image is as follows: the recording of the first recording sequence "T1WI" in Table 62 ends, and the recording parameters of the second recording sequence "T2WI" are set.

[0120] then, Figure 7 The first display example shows a user interface related to camera parameters. Figure 7 This is an enlarged view of the settings window 63. Here, we assume the operator inputs a value for the camera parameter "TR". For example, when the TR box is clicked, as a user interface, the slider 71 and the cursor 72 representing the current value are displayed in different windows.

[0121] With other imaging conditions such as the number of slices fixed, if TR increases, the period during which the tilted magnetic field is not output is prolonged, thus reducing the heat generation [W] per unit time. In the direction where TR shortens, a lower limit is set in a way that prevents the cursor 72 from sliding to a value that does not meet the limiting imaging conditions of the heat input surface, and this lower limit value is displayed so that the operator can understand the lower limit. Figure 7In the example, if the extreme imaging conditions of the hot input surface are not considered, the cursor 72 can be moved to "10ms". However, to avoid moving the cursor 72 to a position below the lower limit of the extreme imaging conditions of the hot input surface, "40ms", it is displayed in gray. Figure 7 The diagonal part is displayed.

[0122] Next, in Figure 8 The second display example shows a user interface related to camera parameters. Figure 8 This is also a magnified view of the settings window 63. Here, we assume the operator enters a value for the camera parameter "resolution". For example, if the "resolution" box is clicked, list window 81 is displayed as the user interface.

[0123] The smaller the resolution value, i.e., the higher the resolution, the greater the heat generated in the superconducting magnet. Therefore, a lower limit is set so that the direction of increasing heat input, i.e., values ​​with low resolution that do not meet the extreme imaging conditions, cannot be selected (input), and this is displayed so that the operator can understand the lower limit. Figure 8 In the example, when the extreme camera condition is set to "2mm", if the extreme camera condition is not considered, it is possible to select up to "1mm". However, to avoid selecting values ​​below the lower limit of "2mm" that constitutes the extreme camera condition, such as "1mm" and "0, 5mm", gray is used. Figure 8 The diagonal part is displayed.

[0124] Furthermore, when the processing circuit 131 receives a change in camera parameters from the operator through the input restriction function on the user interface screen, it can also update the input range of other camera parameters related to the camera conditions. For example, with Figure 7 as well as Figure 8 For example, based on extreme imaging conditions, when the resolution changes from "3mm" to "10mm", it is assumed that the limit of the heat input to the superconducting magnet is slightly mitigated. Therefore, it can be updated simply by changing the TR of the imaging parameters to "8000ms".

[0125] According to the embodiment described above, before determining the imaging conditions, limiting imaging conditions are calculated based on a calorific value database and one or more imaging parameters, and the input range of imaging parameters from the operator is limited based on these limiting imaging conditions. Therefore, the input imaging conditions are limited to the range where imaging is possible, and imaging can be performed under the input imaging conditions. Thus, during the imaging stage, there is no need to reset the imaging conditions or re-encode the imaging. As a result, efficient inspection can be assisted.

[0126] Furthermore, the functions of each implementation method can also be achieved by installing the programs that perform the processing in a computer such as a workstation and expanding them in memory. In this case, the programs that enable the computer to execute the method can also be stored in storage media such as disks (hard disks, etc.), optical discs (CD-ROMs, DVDs, Blu-ray discs, etc.), and semiconductor memories, and distributed.

[0127] Several embodiments have been described, but these embodiments are given by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other ways, and various omissions, substitutions, modifications, and combinations of embodiments are possible without departing from the spirit of the invention. These embodiments and their variations are included in the scope or spirit of the invention, as well as in the scope of the invention as described in the claims and its equivalents.

Claims

1. A magnetic resonance imaging device, comprising: The calculation unit calculates the limiting imaging conditions based on one or more imaging parameters used to determine the imaging conditions and based on a calorific value database that stores the correspondence between imaging conditions and heat generation. The limiting imaging conditions are the limits that can be tolerated for the heat input to the superconducting magnet and are based on the heat that does not cause quenching. The input limiting unit, based on the extreme imaging conditions, limits the input range of imaging parameters from the operator; and The user interface displays, based on the extreme imaging conditions, the remaining temperature from the current temperature of the superconducting magnet to the critical temperature, or the percentage of the temperature before reaching the critical temperature.

2. The magnetic resonance imaging device according to claim 1, wherein, It also includes a prompting unit that prompts the operator to at least one of the extreme camera conditions and a transformation value, the transformation value being obtained by transforming the extreme camera conditions into a risk-related value.

3. The magnetic resonance imaging apparatus according to claim 1 or 2, wherein, The input restriction unit sets an upper or lower limit value for one or more camera parameters based on the extreme camera conditions, and restricts the input by preventing values ​​larger than the upper limit value and values ​​smaller than the lower limit value from being entered.

4. The magnetic resonance imaging apparatus according to claim 1, wherein, The user interface receives input from the operator for one or more camera parameters used to determine camera conditions.

5. The magnetic resonance imaging apparatus according to claim 1, wherein, When the user interface receives a change in camera parameters from the operator, the input restriction unit changes the input range restricted to other camera parameters related to the camera conditions.

6. The magnetic resonance imaging apparatus according to claim 1, wherein, The user interface displays a slider that can be adjusted to the value of the object's camera parameters. The input limit is displayed and set on the slider in such a way that it cannot slide to a value that does not meet the limiting imaging conditions in the direction of increasing heat input related to the superconducting magnet.

7. A video surveillance management method, comprising the following steps: Based on one or more imaging parameters used to determine imaging conditions, and based on a calorific value database that stores the correspondence between imaging conditions and heat generation, the limiting imaging conditions are calculated. These limiting imaging conditions are the limits that can be tolerated for the heat input to the superconducting magnet, and are based on the heat that does not cause quenching. Based on the aforementioned extreme imaging conditions, the input range of imaging parameters from the operator is limited; and Based on the aforementioned extreme imaging conditions, the remaining temperature from the current temperature of the superconducting magnet to the critical temperature, or the percentage of the temperature remaining until the critical temperature is reached, is displayed.

Images