JP5686836B2 - Magnetic resonance imaging system - Google Patents

Description

  The present invention relates to a magnetic resonance imaging apparatus that captures an image of a subject by collecting data related to the inside of the subject using a magnetic resonance phenomenon.

  Conventionally, a magnetic resonance imaging apparatus is an apparatus that images an arbitrary cross section of a subject such as a human body with various contrasts between tissues. In such a magnetic resonance imaging apparatus, a procedure called a pulse sequence (pulse sequence) is executed, in which events indicating the timing of applying a high-frequency pulse or a gradient magnetic field pulse or the timing of data collection are defined in time series. Thus, imaging is performed.

  An operator of the magnetic resonance imaging apparatus appropriately sets various imaging parameters prior to imaging, and obtains information such as contrast, SN ratio, spatial resolution, flow velocity, and diffusion required for the examination. The imaging parameters here include, for example, repetition time (TR), echo time (TE), number of matrices, imaging area (FOV: Field Of View), number of slices, slice thickness, and the like.

  FIG. 11 is a diagram showing an example of a user interface for editing imaging parameters in a conventional magnetic resonance imaging apparatus. This figure shows an imaging condition editing screen with various imaging parameters as edit items. For example, the operator sets values of necessary imaging parameters by inputting numerical values on the imaging condition editing screen shown in the figure or operating a user interface such as a slider or button.

  In addition to the imaging parameters exemplified above, the operator can also select imaging methods (pulse sequence types such as spin echo method and EPI (Echo Planar Imaging) method), types of prepulses such as fat suppression pulses and inversion pulses, The imaging condition is edited according to the purpose, such as the number, order, and slice excitation order. As a technique for confirming the spatial arrangement of these pre-pulses and imaging pulses, there is a technique for displaying a slice region on a positioning image (see, for example, Patent Document 1). The positioning image used in this technique is called “graphic locator” or the like.

JP 2003-290171 A

  However, in the conventional technique described above, the operator can confirm the spatial arrangement of the pre-pulse and the imaging pulse, but cannot confirm the temporal order of the pre-pulse and the imaging pulse. That is, in the conventional technology, when the operator changes the imaging condition, the timing at which the target imaging position is collected, what pre-pulse is applied, in what order and frequency, etc. Information that affects the resulting image cannot be obtained.

  The present invention has been made to solve the above-described problems caused by the prior art, and provides a magnetic resonance imaging apparatus in which an operator can easily confirm the influence on an image by changing imaging parameters. Objective.

To solve the above problems and achieve the object, the present invention provides a magnetic resonance imaging apparatus to gather data about utilizing a magnetic resonance phenomenon in the test body, the display unit the imaging condition editing screen is displayed on the display and imaging condition editing means for accepting the setting of the imaging parameters from the operator, an event that includes a collection of application and data flop Riparusu type, execution order, and a time chart showing the time interval on the display unit Chart display control means, and when the chart display control means accepts an imaging parameter setting change from an operator on the imaging condition editing screen during display of the time chart, the chart display control means displays based on the setting change. The inside time chart is changed .

Further, the present invention provides a magnetic resonance imaging apparatus to gather data about utilizing a magnetic resonance phenomenon in the test body, including imaging condition editing screen, as well as a collection of application and data pre-pulse events type, execution order, and time chart indicative of a time interval, and, a positioning image representing at least one of the position of the application region and collection region of the data pre-pulse, a display control unit that Ru is displayed on the display unit, the The display control means controls the display of the position of the pre-pulse application area or the data collection area in the positioning image and the display of the event in the time chart in association with each event during editing of the imaging condition. And

  According to the present invention, there is an effect that the operator can easily confirm the influence on the image due to the change of the imaging parameter.

1 is a diagram illustrating an overall configuration of an MRI apparatus according to a first embodiment. FIG. 3 is a functional block diagram illustrating a detailed configuration of the computer system according to the first embodiment. It is a figure for demonstrating the display of the time chart by an imaging condition edit / imaging positioning part. It is a figure for demonstrating the display of the time chart when a presat button is pushed. It is a figure for demonstrating the display of the time chart when an interleave button is pushed. 6 is a flowchart illustrating a processing procedure of a time chart display by the MRI apparatus according to the first embodiment. It is a figure which shows an example of the time chart regarding the coronary artery imaging combined with electrocardiogram synchronization. It is a figure which shows an example of the time chart regarding the imaging by a segment division | segmentation type | mold field echo method. It is a figure which shows an example of the time chart regarding the imaging by Time-SLIP method. It is a figure which shows an example of the time chart in the case of displaying the position in k space of collection data. It is a figure which shows an example of the user interface for editing the imaging parameter in the conventional magnetic resonance imaging apparatus.

  Exemplary embodiments of a magnetic resonance imaging apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. In the following embodiments, the magnetic resonance imaging apparatus is referred to as an “MRI (Magnetic Resonance Imaging) apparatus”.

  First, the overall configuration of the MRI apparatus according to the first embodiment will be described with reference to FIG. FIG. 1 is a diagram illustrating an overall configuration of the MRI apparatus according to the first embodiment. As shown in the figure, the MRI apparatus 100 according to the first embodiment includes a static magnetic field magnet 1, a gradient magnetic field coil 2, a gradient magnetic field power source 3, a bed 4, a bed control unit 5, a transmission RF coil 6, a transmission unit 7, A reception RF coil 8, a reception unit 9, and a computer system 10 are provided.

  The static magnetic field magnet 1 is a magnet formed in a hollow cylindrical shape, and generates a uniform static magnetic field in an internal space. As the static magnetic field magnet 1, for example, a permanent magnet, a superconducting magnet or the like is used.

  The gradient magnetic field coil 2 is a coil formed in a hollow cylindrical shape, and is disposed inside the static magnetic field magnet 1. The gradient magnetic field coil 2 is formed by combining three coils corresponding to the X, Y, and Z axes orthogonal to each other, and these three coils are individually supplied with current from a gradient magnetic field power source 3 to be described later. In response, a gradient magnetic field whose magnetic field strength changes along the X, Y, and Z axes is generated. The Z-axis direction is the same direction as the static magnetic field.

  Here, the gradient magnetic fields of the X, Y, and Z axes generated by the gradient magnetic field coil 2 correspond to, for example, the slice selection gradient magnetic field Gs, the phase encoding gradient magnetic field Ge, and the readout gradient magnetic field Gr, respectively. . The slice selection gradient magnetic field Gs is used to arbitrarily determine an imaging section. The phase encoding gradient magnetic field Ge is used to change the phase of the magnetic resonance signal in accordance with the spatial position. The readout gradient magnetic field Gr is used for changing the frequency of the magnetic resonance signal in accordance with the spatial position.

  The gradient magnetic field power supply 3 is a device that supplies a current to the gradient coil 2 based on pulse sequence execution data sent from the computer system 10.

  The couch 4 is a device including a couchtop 4a on which the subject P is placed, and the couchtop 4a is tilted in a state where the subject P is placed under the control of a couch controller 5 described later. The magnetic field coil 2 is inserted into the cavity (imaging port). Usually, the bed 4 is installed such that the longitudinal direction is parallel to the central axis of the static magnetic field magnet 1.

  The couch controller 5 is a device that controls the couch 4 and drives the couch 4 to move the top 4a in the longitudinal direction and the vertical direction.

  The transmission RF coil 6 is a coil disposed inside the gradient magnetic field coil 2 and receives a high frequency pulse from the transmission unit 7 to generate a high frequency magnetic field.

  The transmission unit 7 is a device that transmits a high-frequency pulse corresponding to the Larmor frequency to the transmission RF coil 6 based on the pulse sequence execution data transmitted from the computer system 10, and includes an oscillation unit, a phase selection unit, a frequency conversion unit, an amplitude A modulation unit, a high frequency power amplification unit, and the like are included. The oscillation unit generates a high-frequency signal having a resonance frequency unique to the target nucleus in the static magnetic field. The phase selection unit selects the phase of the high-frequency signal. The frequency conversion unit converts the frequency of the high-frequency signal output from the phase selection unit. The amplitude modulation unit modulates the amplitude of the high-frequency signal output from the frequency modulation unit according to, for example, a sinc function. The high frequency power amplification unit amplifies the high frequency signal output from the amplitude modulation unit. As a result of the operation of each of these units, the transmission unit 7 transmits a high-frequency pulse corresponding to the Larmor frequency to the transmission RF coil 6.

  The reception RF coil 8 is a coil disposed inside the gradient magnetic field coil 2 and receives a magnetic resonance signal radiated from the subject due to the influence of the high-frequency magnetic field. When receiving the magnetic resonance signal, the reception RF coil 8 outputs the magnetic resonance signal to the receiving unit 9.

  The receiving unit 9 is a device that generates magnetic resonance signal data based on the magnetic resonance signal output from the reception RF coil 8 based on the pulse sequence execution data sent from the computer system 10. When receiving the magnetic resonance signal data, the receiving unit 9 transmits the magnetic resonance signal data to the computer system 10.

  The computer system 10 is a device that performs overall control of the MRI apparatus 100, data collection, image reconstruction, and the like, and includes an interface unit 11, a data collection unit 12, a data processing unit 13, a storage unit 14, a display unit 15, and an input unit. 16 and a control unit 17.

  The interface unit 11 is connected to the gradient magnetic field power source 3, the bed control unit 5, the transmission unit 7, and the reception unit 9, and inputs and outputs signals that are exchanged between these connected units and the computer system 10. A processing unit to be controlled.

  The data collection unit 12 is a processing unit that collects magnetic resonance signal data transmitted from the reception unit 9 via the interface unit 11. When collecting the magnetic resonance signal data, the data collecting unit 12 stores the collected magnetic resonance signal data in the storage unit 14.

  The data processing unit 13 performs post-processing, that is, reconstruction processing such as Fourier transform, on the magnetic resonance signal data stored in the storage unit 14, thereby obtaining spectrum data of desired nuclear spins in the subject P or A processing unit that generates image data.

  The storage unit 14 is a storage unit that stores the magnetic resonance signal data collected by the data collection unit 12 and the image data generated by the data processing unit 13 for each subject P.

  The display unit 15 is a device that displays various information such as spectrum data or image data under the control of the control unit 17. As the display unit 15, a display device such as a liquid crystal display can be used.

  The input unit 16 is a device that receives various operations and information input from an operator. As the input unit 16, a pointing device such as a mouse or a trackball, a selection device such as a mode change switch, or an input device such as a keyboard can be used as appropriate.

  The control unit 17 includes a CPU, a memory, and the like (not shown), and is a processing unit that comprehensively controls the MRI apparatus 100.

  The overall configuration of the MRI apparatus 100 according to the first embodiment has been described above. Under such a configuration, in the MRI apparatus 100 according to the first embodiment, the computer system 10 determines at what timing the target imaging position is collected based on the set imaging condition, and what kind of prepulse By displaying on the display unit 15 a “time chart” indicating the order and frequency in which images are applied, the operator can easily confirm the influence on the image due to the change of the imaging parameter. I have to.

  Hereinafter, the functions of the computer system 10 will be specifically described. First, the detailed configuration of the computer system 10 according to the first embodiment will be described in detail with reference to FIG. FIG. 2 is a functional block diagram illustrating a detailed configuration of the computer system 10 according to the first embodiment. The figure shows the configuration of the display unit 15, the control unit 17, and the storage unit 14 that are particularly relevant to the present invention, and the interface unit 11, the storage unit 14, the display unit 15, the input unit 16, and the control unit 17. It shows the mutual relationship.

  As shown in the figure, the storage unit 14 stores inspection information 14a as information particularly relevant to the present invention. The inspection information 14a is information indicating imaging conditions corresponding to various types of imaging, and is set in various imaging parameters that constitute the imaging conditions, such as the type of imaging, the position of a slice (cross section), the slice thickness, and the number of slices. Contains a value.

  As shown in the figure, the display unit 15 includes an imaging condition edit display unit 15a, a positioning display unit 15b, and a time chart display unit 15c as functional units particularly relevant to the present invention.

  The imaging condition edit display unit 15a is a display unit that displays information regarding imaging conditions. Specifically, the imaging condition editing / display unit 15a is controlled by an imaging condition editing / imaging positioning unit 17a, which will be described later, from an area for inputting / outputting information on imaging conditions for each imaging parameter, or from an operator. An imaging condition editing screen having a user interface for receiving various operations is displayed.

  The positioning display unit 15b displays a positioning image that serves as a reference when determining the position of the slice to be imaged, and displays a graphic indicating the slice area on the positioning image based on the imaging conditions set by the operator. It is a display unit. The positioning display unit 15b changes the position and shape of the graphic indicating the slice area in conjunction with the display of the imaging condition by the imaging condition editing display unit 15a when the imaging condition is changed by the operator. .

  The time chart display unit 15c is a display unit that displays a time chart generated by an imaging condition editing / imaging positioning unit 17a described later.

  As shown in the figure, the control unit 17 has an imaging condition editing / imaging positioning unit 17a, an imaging parameter limit calculation unit 17b, and a pulse sequence execution data generation unit 17c as functional units particularly related to the present invention. doing.

  The imaging condition editing / imaging positioning unit 17a receives information relating to editing of imaging conditions and positioning of slices, and at the time of collecting magnetic resonance signal data based on examination information 14a generated by an imaging parameter limit calculation unit 17b described later. It is a processing unit that generates a time chart indicating the type and order of events to be executed and displays the time chart on the time chart display unit 15c.

  Specifically, when the imaging condition editing / imaging positioning unit 17a first receives a display request of the imaging condition editing screen 20 from the operator via the input unit 16, the imaging condition editing / displaying unit 15a The imaging condition editing screen 20 is displayed by controlling.

  When the imaging condition editing / imaging positioning unit 17a receives an operation for setting a value to the imaging parameter of the imaging condition editing screen 20 from the operator via the input unit 16, the imaging value editing / imaging positioning unit 17a uses the set value as the imaging parameter. Each time it is handed over to the imaging parameter limit calculator 17b. When the limit value of the imaging parameter is responded from the imaging parameter limit calculation unit 17b, the imaging condition editing / imaging positioning unit 17a controls the imaging condition editing display unit 15a to capture the responded limit value. Each parameter is displayed on the imaging condition editing screen 20.

  In addition, when the imaging condition editing / imaging positioning unit 17a receives a time chart display request from the operator via the input unit 16, the imaging condition editing / imaging positioning unit 17a reads and reads the inspection information 14a stored in the storage unit 14. Based on the inspection information 14a, a time chart representing the types of events executed at the time of data collection and the execution sequence in time series is generated.

  At this time, when the imaging condition editing / imaging positioning unit 17a generates the time chart, the imaging condition editing / imaging positioning unit 17a generates the time chart 30 so that the time interval of the event to be executed is represented. Then, the imaging condition editing / imaging positioning unit 17a controls the time chart display unit 15c to display the generated time chart.

  Here, the display of the time chart by the imaging condition editing / imaging positioning unit 17a will be described in detail with reference to FIG. FIG. 3 is a diagram for explaining display of a time chart by the imaging condition editing / imaging positioning unit 17a. FIG. 5A shows an example of the imaging condition editing screen 20 displayed by the imaging condition editing display unit 15a.

  As shown in the figure, for example, the imaging condition editing screen 20 displays an area for displaying values set for each imaging parameter such as “TR”, “number of slices”, “slice thickness”, “number of integrations”, and the like. Have. In this imaging condition editing screen 20, the maximum number of slices that can be imaged within the set repetition time is the other imaging conditions and other information (for example, patient weight and high frequency) stored in the storage unit 14 as examination information 14a. Calculated with reference to transmission power, etc.). The example in the figure shows a case where a two-dimensional spin echo image is collected by the multi-slice method, and shows a case where six slices are collected within a repetition time TR = 500 milliseconds.

  The imaging condition editing screen 20 includes, for example, a presat button 21, an interleave button 22, a sequence chart button 23, and the like as buttons for receiving various operations from the operator as shown in FIG. The presat button 21 is a button for accepting a setting request for a presaturation pulse for suppressing a signal from an unnecessary part to be imaged from an operator. The interleave button 22 is a button for accepting a request to change the slice collection order within the repetition time. The sequence chart button 23 is a button for accepting a time chart display request.

  In the imaging condition editing screen 20, when the sequence chart button 23 is pressed by the operator via the input unit 16, the imaging condition editing / imaging positioning unit 17a, as shown in FIG. For example, a time chart 30 in which graphics representing data collection for 6 slices are arranged in time series is generated. In the figure, “acq” represents data collection, and “S1” to “S6” represent slice numbers 1 to 6, respectively. This time chart 30 shows that data collection of each slice is performed in the order of slice numbers within the repetition time.

  The imaging condition editing / imaging positioning unit 17a controls the imaging parameter limit calculating unit 17b when the operator presses the presat button 21 on the imaging condition editing screen 20 via the input unit 16. After recalculating the number of slices, the display of the imaging condition editing screen 20 and the time chart 30 is changed based on the calculation result.

  Specifically, the imaging condition editing / imaging positioning unit 17a controls the imaging parameter limit calculation unit 17b to collect data for each slice when the operator presses the presat button 21 on the imaging condition editing screen 20. When the presaturation pulse is added immediately before, the number of slices that can be imaged within the repetition time is recalculated, and the recalculated number of slices is displayed on the imaging condition editing screen 20.

  FIG. 4 is a diagram for explaining the display of the time chart 30 when the presat button 21 is pressed. When the presat button 21 is pressed, the imaging condition editing / imaging positioning unit 17a changes the display of the number of slices from “6” to “5”, for example, as shown in FIG.

  Further, the imaging condition editing / imaging positioning unit 17a changes the display of the time chart 30 displayed on the time chart display unit 15c based on the number of slices recalculated by the imaging parameter limit calculation unit 17b.

  For example, the imaging condition editing / imaging positioning unit 17a changes the number of figures indicating data collection displayed on the time chart 30 from six to five as shown in FIG. A figure “p” representing a presaturation pulse is added immediately before “S1” to “S5” indicating collection.

  As described above, when the imaging condition editing / imaging positioning unit 17a changes the display of the time chart 30 when the operator presses the presat button 21, the operator can apply the presaturation pulse. In this case, the change of the pulse sequence, the process of decreasing the number of slices, the frequency of applying the presaturation pulse, etc. can be easily confirmed visually.

  The imaging condition editing / imaging positioning unit 17a controls the imaging parameter limit calculation unit 17b when the operator presses the interleave button 22 on the imaging condition editing screen 20 via the input unit 16. After changing the slice collection order within the repetition time, the unit changes the display of the time chart 30 based on the result.

  FIG. 5 is a diagram for explaining the display of the time chart 30 when the interleave button 22 is pressed. As shown in FIG. 6A, when the interleave button 22 is pressed, the imaging condition editing / imaging positioning unit 17a is displayed on the time chart 30 as shown in FIG. The slice collection order is switched from “S1”, “S2”, “S3”, “S4”, “S5” in the order of “S1”, “S3”, “S5”, “S2”, “S4”.

  Conventionally, a change in the slice collection order due to a change in the imaging parameter cannot be easily confirmed. However, according to the first embodiment, as shown in FIG. 4B, the time chart 30 indicates that the order of slice excitation has changed so that the odd number is collected first and the even number is collected later. Since it is clearly shown, the operator can easily confirm the change in the slice collection order by comparing with the state shown in FIG.

  Furthermore, in the first embodiment, the imaging condition editing / imaging positioning unit 17a links the display on the positioning image by the positioning display unit 15b with the display of the imaging condition editing screen 20 and the time chart 30 for each event. Thus, it is possible to more clearly notify the operator of the influence on the image due to the change of the imaging condition.

  For example, FIG.5 (c) has shown the example which plans the imaging position of the next cross section on the positioning image 40 of the sagittal section of the neck. In the figure, squares with numbers “1” to “5” represent the positions of slices (slice regions), respectively. Here, the slice 1 corresponds to the slice S1 of the time chart 30 shown in FIG. 2B, and the slice 2 also corresponds to the slice S2 of the time chart 30. Similarly, slices 3, 4, and 5 correspond to slices S3, S4, and S5 of the time chart 30, respectively.

  As described above, the imaging condition editing / imaging positioning unit 17a displays the slices in the time chart 30 and the slices in the positioning image 40 in association with the slice numbers, so that the operator can perform within one repetition time. Excitation of slices is performed every other sheet from the head side of the subject, and then it becomes possible to easily recognize that the slices in between are excited. In other words, when there is interference between slices due to the deviation of the slice characteristic from the ideal state, the operator can easily recognize that the excitation order is such that the interference is reduced.

  Further, the imaging condition editing / imaging positioning unit 17a displays a figure P1 indicating the position of the presaturation pulse on the positioning image 40 as shown in FIG. Thereby, the operator can grasp | ascertain easily the part excited before each slice data acquisition.

  In addition, the imaging condition editing / imaging positioning unit 17a corresponds to the slice 3 on the time chart 30 when, for example, the operator designates the slice 3 on the positioning image 40 via the input unit 16. The slice S3 to be highlighted is highlighted. On the other hand, for example, when the slice S3 is designated on the time chart 30 by the operator, the imaging condition editing / imaging positioning unit 17a corresponds to the slice corresponding to the slice 3 on the positioning image 40. S3 is highlighted.

  As described above, the imaging condition editing / imaging positioning unit 17a changes the display of the slice of the time chart 30 or the positioning image 40 so that the correspondence between the slice on the time chart 30 and the slice on the positioning image 40 is indicated. By doing so, the spatial arrangement and the temporal arrangement of data collection can be associated with each other and shown to the operator.

  Returning to FIG. 2, the imaging parameter limit calculation unit 17 b is a processing unit that generates examination information indicating imaging conditions related to calculation of limit values of imaging parameters and collection of magnetic resonance signal data. Specifically, when the imaging parameter limit calculation unit 17b receives the imaging parameter value from the imaging condition editing / imaging positioning unit 17a, the imaging parameter limit calculation unit 17b calculates a limit value of another imaging parameter depending on the imaging parameter value. .

  Then, the imaging parameter limit calculation unit 17b returns the calculated imaging parameter limit value to the imaging condition editing / imaging positioning unit 17a, and each time based on the delivered imaging parameter value and the calculated imaging parameter value. Thus, examination information 14a indicating imaging conditions related to collection of magnetic resonance signal data is generated and stored in the storage unit 14.

  The pulse sequence execution data generation unit 17 c is a processing unit that executes imaging using the examination information 14 a stored in the storage unit 14. Specifically, when the pulse sequence execution data generation unit 17c receives an imaging start instruction from the operator via the input unit 16, the imaging condition stored as the examination information 14a in the storage unit 14 Based on the above, the pulse sequence execution data 17d is generated, and the generated pulse sequence execution data 17d is transmitted via the interface unit 11, thereby causing the gradient magnetic field power source 3, the transmission unit 7, and the reception unit 9 to perform imaging.

  Next, a time chart display processing procedure performed by the MRI apparatus 100 according to the first embodiment will be described. FIG. 6 is a flowchart illustrating the processing procedure of the time chart display by the MRI apparatus 100 according to the first embodiment.

  As shown in the figure, in the MRI apparatus 100, when a display request for the imaging condition editing screen 20 is received from the operator, the imaging condition editing / imaging positioning unit 17a controls the imaging condition editing display unit 15a to control the imaging conditions. The editing screen 20 is displayed (step S101), and setting of imaging conditions is accepted (step S102).

  When the imaging condition is set from the imaging condition editing screen 20 by the operator, the imaging parameter limit calculation unit 17b generates the inspection information 14a based on the set imaging condition (step S103).

  Thereafter, when the sequence chart button 23 on the imaging condition editing screen 20 is pressed by the operator (Yes in step S104), the imaging condition editing / imaging positioning unit 17a is inspected by the imaging parameter limit calculating unit 17b. After generating the time chart 30 based on the information 14a, the time chart display unit 15c is controlled to display the generated time chart 30 (step S105).

  Here, when the presat button 21 on the imaging condition editing screen 20 is pressed by the operator (step S106, Yes), the imaging parameter limit calculation unit 17b recalculates the number of slices (step S107), and imaging is performed. The condition editing / imaging positioning unit 17a changes the display of the time chart 30 based on the recalculated number of slices (step S108).

  When the interleave button 22 on the imaging condition editing screen 20 is pressed by the operator (step S109, Yes), the imaging parameter limit calculation unit 17b switches the slice collection order (step S110), and edits the imaging condition / The imaging positioning unit 17a changes the display of the time chart 30 based on the replaced slice collection order (step S111).

  As described above, in the first embodiment, the imaging parameter limit calculation unit 17b generates the inspection information 14a indicating the imaging conditions regarding the collection of the magnetic resonance signal data, based on the imaging parameter value set by the operator. Then, the imaging condition editing / imaging positioning unit 17a represents the types of events and the time-series execution order executed when collecting the magnetic resonance signal data based on the examination information 14a generated by the imaging parameter limit calculation unit 17b. Since the time chart 30 is generated and displayed on the time chart display unit 15c, the operator can easily confirm the influence on the image due to the change of the imaging parameter.

  In the first embodiment, the display of the time chart 30 when a two-dimensional spin echo image is acquired by the multi-slice method has been described with reference to FIGS. It is not necessarily restricted to what was shown to -5, The display form suitable for every kind of imaging may be used. Therefore, in the following, as a second embodiment, a modification of the time chart 30 corresponding to the type of imaging will be described. In the second embodiment, the processing performed by the imaging condition editing / imaging positioning unit 17a will be mainly described.

(1) Coronary Artery Imaging Using ECG Synchronization First, display of a time chart regarding coronary imaging using ECG synchronization will be described. In coronary artery imaging combined with electrocardiogram synchronization, usually pre-pulses for imparting T2 contrast, data collection for detecting body motion and correcting motion, and suppressing unnecessary signals outside the region of interest Various pre-pulses such as a pre-saturation pulse, a pulse for suppressing a fat signal, and a dummy pulse for promoting a steady state are applied prior to actual data collection.

  Therefore, when the examination information 14a read out from the storage unit 14 indicates imaging conditions for coronary artery imaging combined with electrocardiogram synchronization, the imaging condition editing / imaging positioning unit 17a displays the various pre-pulses described above. The time chart is displayed on the time chart display unit 15c.

  FIG. 7 is a diagram illustrating an example of a time chart relating to coronary artery imaging combined with electrocardiogram synchronization. As shown in the figure, for example, the imaging condition editing / imaging positioning unit 17a collects a figure “T2prep” indicating a pre-pulse for imparting T2 contrast and data collection for detecting a body motion and correcting the motion. A figure “Nav”, a figure “p” showing a presaturation pulse for suppressing an unnecessary signal outside the region of interest, a figure “F” showing a pulse for suppressing a fat signal, and a steady state A time chart 130 in which a figure “D” indicating a dummy pulse or the like is arranged before “acq” indicating data collection is displayed on the time chart display unit 15c.

  Since coronary artery imaging combined with electrocardiogram synchronization is performed in synchronization with the subject's electrocardiogram waveform, each event always occurs at a relative time from the R wave. Therefore, the imaging condition editing / imaging positioning unit 17a displays a simulated electrocardiogram waveform on the time chart 130 as shown in the figure, and further displays the time of the RR interval (shown in the figure) in the simulated electrocardiogram waveform. “R−R = 950”) is displayed. Further, the imaging condition editing / imaging positioning unit 17a displays a delay time ("Td = 200" shown in the figure) from the R wave to the pre-pulse for providing the T2 contrast.

  Thus, the imaging condition editing / imaging positioning unit 17a displays the electrocardiogram waveform, the time of the RR interval, and the delay time from the R wave together with the time chart 130, so that the operator can start from the R wave. After the delay time of 200 milliseconds, each pre-pulse is applied for a predetermined period, and then a pulse sequence in which data collection is performed in a time phase corresponding to the expansion period after the dummy pulse is applied is visually observed. It can be easily confirmed.

  In coronary artery imaging combined with ECG synchronization, the factors that affect image quality are that data collection is performed in a diastole with relatively little movement of the heart, and the data collection time within one heartbeat is within the total imaging time. For example, the fat suppression pulse “F”, data collection “Nav” for detecting motion, and the like may be executed as close to the data collection “acq” as possible.

  Conventionally, it has been difficult for an operator to understand whether or not the imaging parameters that cause these factors are appropriately set only by the imaging condition setting screen. However, according to the present embodiment, the time chart 130 is displayed together with the electrocardiogram waveform, the time of the RR interval, and the delay time from the R wave to the pre-pulse for giving the T2 contrast. The operator can easily determine whether or not the parameters are set appropriately.

  Furthermore, the imaging condition editing / imaging positioning unit 17a may further enlarge and display a part specified by the operator in the displayed time chart 130 in detail. The chart enlarged view 131 shown in the figure shows an enlarged view of the data collection unit “acq”, and shows that “acq” is composed of four consecutive field echo collections.

  Usually, in the operation of setting the imaging conditions, it is not always required to know more detailed pulse sequence information than the enlarged chart 131 shown in FIG. However, the imaging condition editing / imaging positioning unit 17a further enlarges the enlarged chart 131 to display details (for example, a high-frequency pulse, a gradient magnetic field pulse for slice selection, a gradient magnetic field pulse for phase encoding, and a frequency encoding) (E.g., a pulse sequence is displayed for each type of pulse). In that case, the imaging condition editing / imaging positioning unit 17a controls, for example, how much detailed information is disclosed according to the qualification of the operator.

(2) Imaging by division type field echo method Next, a time chart regarding imaging by the segment division type field echo method in which k space is divided into a plurality of units called segments and prepulses are applied or ECG synchronization is performed for each segment. The display will be described.

  Specifically, when the examination information 14a read from the storage unit 14 indicates imaging conditions for imaging by the divided field echo method, the imaging condition editing / imaging positioning unit 17a includes a figure indicating a fat suppression prepulse, A time chart in which graphics indicating segments are alternately arranged is displayed on the time chart display unit 15c.

  FIG. 8 is a diagram showing an example of a time chart related to imaging by the segmented field echo method, and shows a case where a fat suppression prepulse is used together. As shown in FIG. 6A, for example, when the number of segments is 2, the imaging condition editing / imaging positioning unit 17a indicates “F” indicating a fat suppression pre-pulse and a graphic “Seg1” indicating the first segment. ", A time chart 230 in which" F "indicating a fat suppression pre-pulse and" Seg2 "indicating a second segment are arranged in order.

  For example, when the number of segments is changed to 8 by the operator, the imaging condition editing / imaging positioning unit 17a increases the figure indicating the segment to 8 as shown in FIG. The display of the time chart 230 is changed so that the fat suppression prepulse “F” is placed immediately before each of the figures “Seg1” to “Seg8” indicating the segments.

  As described above, the imaging condition editing / imaging positioning unit 17a changes the display of the time chart 230 based on the number of segments set by the operator, so that the operator can increase the number of fat suppression pulses as a result. Even if the imaging conditions other than the number are all the same, it is possible to easily confirm that the fat suppression effect is improved because the total imaging time is increased and the frequency of fat suppression pulses is increased instead.

  The influence on the imaging time and image quality due to such a change in imaging conditions can be explained only by showing the timing of the pulse sequence. This is usually described in the instruction manual of the device, etc., but as described above, when the imaging conditions are edited, the change in the imaging conditions is indicated at the same time, so that the operator has more influence on the image quality. Become able to understand well.

(3) Blood vessel imaging by ASL (Arterial Spin Labeling) Next, display of a time chart regarding blood vessel imaging by ASL will be described. Here, a method called Time-SLIP method, which is one method of the ASL method, will be described. The Time-SLIP method is a technique characterized in that a selective inversion pulse region is set independently of an imaging region in order to selectively depict only a specific blood vessel.

  Specifically, when the examination information 14a read from the storage unit 14 indicates imaging conditions for imaging by the Time-SLIP method, the imaging condition editing / imaging positioning unit 17a displays an inversion pulse, data collection, and the like. The time chart is displayed on the time chart display unit 15c.

  FIG. 9 is a diagram illustrating an example of a time chart regarding imaging by the Time-SLIP method. This figure shows a case where only arterial blood flowing into the imaging region is depicted by collecting data after a predetermined time has elapsed after applying the inversion pulse. Moreover, in the example of the same figure, in order to suppress the signal from the venous blood which flows in at the same time, the presaturation pulse is also applied to another region.

  As shown in FIG. 5A, for example, the imaging condition editing / imaging positioning unit 17a includes a graphic “IR” indicating an inversion pulse, a graphic “p” indicating a presaturation pulse, and “acq” indicating data collection. The previously arranged time chart 330 is displayed. The imaging condition editing / imaging positioning unit 17a also displays a simulated electrocardiogram waveform on the time chart 330, and further displays an RR interval time ("RR = 900" shown in the figure) on the simulated electrocardiogram waveform. ) And the time from the inversion pulse to the data collection (“TI = 600” shown in the figure).

  When rendering a specific blood vessel using the ASL method, it is important to set the imaging conditions appropriately taking into account all the travel of the blood vessel, the approximate blood flow velocity, and the timing and position of each pulse. According to the embodiment, together with the time chart 330, the electrocardiogram waveform, the time of the RR interval, and the time from the inversion pulse to the data collection are displayed together, so whether or not the imaging parameters are set appropriately. Can be easily determined by the operator.

  Note that when the time chart 330 displays the graphic “IR” indicating the inversion pulse, the graphic “P” indicating the pre-saturation pulse, and the graphic “acq” indicating the data collection, the imaging condition editing / imaging positioning unit 17 a You may make it display a figure with patterns, such as a different color, a gradation, or a shading for every kind. Then, the imaging condition editing / imaging positioning unit 17a shows the location on the positioning image 340 with the same color, gradation, and pattern as the graphics showing each pulse, as shown in FIG. (Here, a rectangle) may be displayed (in the example of FIG. 5B, the line type of the rectangle is changed instead of changing the color, gradation, and pattern). As a result, the operator can easily understand the correspondence between the spatial position of each pulse and the temporal order.

(4) Display of the position of the collected data in the k space In the MRI apparatus, the influence of the collected data on the image obtained by Fourier transform differs depending on the position of the collected data in the real space (called the k space). Specifically, a signal placed near the center of the k space, that is, in the low frequency region affects the contrast of the image, and the contour of the image is governed by a signal placed outside the k space, that is, in the high frequency region. It is well known that

  Therefore, in the imaging by the MRI apparatus, it may be important in what order the data arranged in the k space is collected. Therefore, the imaging condition editing / imaging positioning unit 17a may display the position of the collected data in the k space on the time chart display unit 15c together with the time chart.

  FIG. 10 is a diagram illustrating an example of a time chart when the position of the collected data in the k space is displayed. This figure shows an example of a time chart in so-called dynamic imaging in which imaging is continuously repeated after injecting a contrast medium from a vein.

  Specifically, the imaging condition editing / imaging positioning unit 17a sets the execution timing of continuous imaging, that is, data collection, when the inspection information 14a read from the storage unit 14 indicates the imaging conditions for dynamic imaging. A time chart displaying the indicated time is displayed on the time chart display unit 15c.

  For example, as shown in FIG. 5A, the imaging condition editing / imaging positioning unit 17a starts data collection for figures “ph.1” to “ph.5” indicating the width of data collection in five time phases. The time chart 430 arranged together with the time to be displayed is displayed. Here, when displaying “ph.1” to “ph.5”, the imaging condition editing / imaging positioning unit 17a has data included within a preset ratio (for example, 25%) from the center of the k space. The collected part is displayed in a different color, gradation or pattern from the other parts.

  The contrast of the image obtained by the Fourier transform is determined by the timing at which k-space center data is collected. Therefore, knowing the time from the start of contrast agent injection when data in the center of the k space is collected is as important as knowing the time of the entire data collection for each time phase in order to obtain an image with appropriate contrast. It is.

  According to the present embodiment, “ph.1” to “ph.5” indicating the width of data collection are displayed with time for each time phase in dynamic imaging, and further, “ph.1” to “ph.5” are displayed. Each displays the position of the collected data in the k space, so that it is possible to easily check whether or not the imaging conditions necessary for obtaining an appropriate contrast image are set correctly. .

  In FIG. 9A, an example is shown in which the collected data is divided into two areas, that is, an area within 25% of the center of the k-space and the other areas. However, the number of divided areas is two. It is not necessarily limited, and it may be divided more finely. In this case, the graphic display indicating the data collection width is more detailed as shown in FIG. FIG. 8C shows the position in the k space of the collected data indicated by the graphic shown in FIG.

  In the embodiment described above, the case where the time chart is displayed in the process of editing the imaging condition has been described. However, the present invention is not limited to this. When the inspection information is updated when is generated, the time chart may be displayed after the pulse sequence execution data is generated.

  As described above, the magnetic resonance imaging apparatus according to the present invention is useful for confirming the influence on the image due to the change of the imaging condition, and particularly for confirming the temporal order of the events executed at the time of data collection. Suitable for

DESCRIPTION OF SYMBOLS 1 Static magnetic field magnet 2 Gradient magnetic field coil 3 Gradient magnetic field power supply 4 Bed 4a Top plate 5 Bed control part 6 Transmission RF coil 7 Transmission part 8 Reception RF coil 9 Reception part 10 Computer system 11 Interface part 12 Data collection part 13 Data processing part 14 Storage unit 14a Inspection information 15 Display unit 15a Imaging condition editing display unit 15b Positioning display unit 15c Time chart display unit 16 Input unit 17 Control unit 17a Imaging condition editing / imaging positioning unit 17b Imaging parameter limit calculation unit 17c Pulse sequence execution data generation unit 17d Pulse sequence execution data 20 Imaging condition editing screen 21 Presat button 22 Interleave button 23 Sequence chart button 30, 130, 230, 330, 430 Time chart 40, 340 Positioning image 100 MRI apparatus (magnetic resonance image) Grayed equipment)
131 Chart enlarged view

Claims (13)

Using the magnetic resonance phenomenon to a magnetic resonance imaging apparatus to gather data about the test object,
To display the imaging condition editing screen on the display unit, and the imaging condition editing means for accepting the setting of the imaging parameters from the operator,
With the type of event, including a collection of application and data flop Riparusu, execution order, and a chart display control means for displaying the time chart on the display unit representing a time interval,
When the chart display control means receives a change in imaging parameter setting from an operator on the imaging condition editing screen while the time chart is being displayed, the chart display control means changes the displayed time chart based on the setting change. A magnetic resonance imaging apparatus.   The magnetic resonance imaging apparatus according to claim 1, wherein the chart display control unit changes a display form of the time chart according to a type of imaging. The magnetic resonance imaging apparatus according to claim 1, wherein the time chart is a time chart including application of a plurality of types of pre- pulses .   The multiple types of pre-pulses include a pre-pulse for imparting T2 contrast, a pre-pulse for detecting body movement and correcting motion, a pre-saturation pulse for suppressing unnecessary signals outside the region of interest, and a fat signal. The magnetic resonance imaging apparatus according to claim 3, wherein the magnetic resonance imaging apparatus is at least two of a pulse for performing a steady state and a dummy pulse for promoting a steady state. The time chart, the magnetic resonance imaging apparatus according to claim 3 or 4, characterized in that a plurality of kinds of time chart arranged information indicating the application of pre-pulse before the information indicating the acquisition of the data.   The chart display control means displays an electrocardiogram waveform together with the time chart when the imaging sequence is coronary artery imaging combined with electrocardiogram synchronization. The magnetic resonance imaging apparatus according to one.   The chart display control means displays the time of an R-R interval or a delay time from an R wave to a pre-pulse for giving a T2 contrast together on the electrocardiogram waveform. Magnetic resonance imaging device.   The magnetic resonance imaging apparatus according to claim 1, wherein the chart display control unit further enlarges and displays a part specified by the operator in the time chart in detail.   The magnetic resonance imaging apparatus according to claim 8, wherein the chart display control unit enlarges and displays the data collection unit as the event type in detail.   The magnetic resonance imaging apparatus according to claim 1, wherein the pre-pulse is an inversion pulse.   The magnetic resonance imaging apparatus according to claim 10, wherein the chart display control unit displays a time from the inversion pulse to data collection together on the time chart. The chart display control means to claim 10 or 11, characterized in that for displaying the time chart in conjunction with the shown to position-decided Me image at least one of the application region and collection region of the data of the inverted pulse The magnetic resonance imaging apparatus described. By utilizing a magnetic resonance phenomenon to a magnetic resonance imaging apparatus to gather data about the test object,
An imaging condition editing screen, a time chart representing the type of event including pre-pulse application and data collection , execution order , and time interval, and the position of at least one of the pre-pulse application area and the data collection area positioning image showing, a display control unit that Ru is displayed on the display unit,
The display control means controls the display of the position of the pre-pulse application area or the data collection area in the positioning image and the display of the event in the time chart in association with each event during editing of the imaging condition. A magnetic resonance imaging apparatus.