JP4327313B2 - MRI equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention,Three-dimensional positioning display device capable of setting a cross section in an arbitrary direction in a three-dimensional image spaceEquipment incorporating MRIAbout.
[0002]
[Prior art]
In general, in a medical modality such as an MR imaging apparatus, it is often necessary to set a cross-section (or volume region) having a desired position and inclination in a three-dimensional space, for example, positioning of an imaging cross-section.
[0003]
Conventionally, such a method for setting a cross section has been implemented in the following manner. One of them captures a reference cross section and displays it as a two-dimensional image. Then, this two-dimensional image is used as a reference screen, and a region of interest section including the orthogonal vector is set. For example, a sagittal plane of a subject is first imaged to display a sagittal image as a reference image, an oblique plane tilted from the axial plane is set with respect to this image, and the oblique image is captured.
[0004]
Another setting method is to use MR continuous imaging (MR fluoroscopy) to rotate and move the two-dimensional reference screen to change the reference section itself or to set an orthogonal section to the reference image. However, this is a method for setting the imaging section in the same manner as the first setting method described above.
[0005]
Further, in the third setting method, a three-dimensional model is displayed in a three-dimensional space by a projection method (projection method), and a cross-sectional position is displayed in the model. Then, the cross section is moved by the first or second setting method described above, and the space grasp of the position is supported.
[0006]
[Problems to be solved by the invention]
However, in the conventional first to third cross-section setting methods described above, since the three-dimensional visibility is low, it is often very difficult to grasp the position on the screen. Currently, there is a case where it is not possible to know at which position the cross section is set or at which position it is going to be set.
[0007]
In particular, in the first setting method, when setting an inclined direction that is not orthogonal to the reference image, the part that intersects the reference section is displayed as a line segment, and the other part is a projected (projected) image. However, it is difficult to grasp spatially and accurate positioning cannot be performed. Further, even when the position of the three-dimensional space is indicated by the third setting method, the operator has to perform association with the two-dimensional image displayed at another place, so the cross section is set at the desired position. From the viewpoint of setting, this setting method is still a simple and easy-to-operate method.
[0008]
  The present invention has been made in view of the problems of the above-described conventional cross-sectional method, and accurately recognizes the spatial positional relationship between the subject and the area to be imaged, while bringing the cross-section into a desired three-dimensional position. Quick, accurate and easy to set upMRI equipmentThe purpose is to provide.
[0009]
  In addition, the present invention displays the image of the imaging region in real time for observation while performing such cross-sectional setting.An MRI apparatus capable of performingFor another purpose.
[0010]
[Means for Solving the Problems]
  To achieve the above object, the present inventionMRI apparatus related toIs at least one placed in the three-dimensional space set for the subject.Cross-sectionalRegion display means for displaying a region, and the subject of the subjectCross-sectionalThe image of the part corresponding to the areaCross sectionImage display means for displaying in a region, and the three-dimensional spaceCross-sectionalChange means for arbitrarily changing at least one of the direction and position of the area;Imaging means for obtaining at least two two-dimensional images by continuously imaging (fluoroscopy) a portion of the subject corresponding to the cross-sectional area;WithThe image display means has paste means for sequentially sticking the two-dimensional image updated corresponding to the cross-sectional area to the cross-sectional area displayed on the area display means.This is a basic feature.SuitableThe area display means is a means for displaying both the cross-sectional area and the three-dimensional absolute coordinate axis set in the three-dimensional space. The operator can easily position the region while viewing the region in the three-dimensional absolute coordinate.Further, the operator can set the position of the imaging section while grasping the spatial positional relationship between the subject and the imaging section.
[0012]
According to another preferable aspect, the image processing apparatus includes a reference image display unit that pastes the two-dimensional image captured at an arbitrary time on another cross-sectional area placed in the coordinate system as a reference image. Also good. By referring to this reference image, the operator can more easily grasp the spatial positional relationship between the subject and the imaging section, and can position the imaging section more accurately.
[0013]
Furthermore, according to one of the preferable aspects, a designation unit that designates a position in the three-dimensional space and a marker display unit that displays a marker corresponding to the designated position in the three-dimensional space are provided. For example, the marker display means is means for displaying the marker in a hue different from that of the two-dimensional image. Thereby, it is possible to make full use of a technique such as moving the cross section to be imaged to the position of the marker, and support the positioning of the imaging cross section.
[0014]
Furthermore, according to another preferable aspect, the position changing means is means for designating a desired three-dimensional position by moving, rotating, and moving the cross-sectional area. . As a result, a series of images can be taken by continuous rotation of the cross section with the offset.
[0015]
Further preferably, there is provided means for recording the three-dimensional position of the imaging region in time series and calling the recorded three-dimensional position. A means for reproducing the two-dimensional image corresponding to the called three-dimensional position in time series may be provided.
[0016]
Furthermore, in a preferred aspect, the position changing means is means for changing the position of the cross-sectional area with respect to the continuous imaging by a reserved routine operation. For example, in this routine operation, a macro description method using a function of time is used as a method for specifying the movement amount of the cross-sectional area. Further, as an example, the position changing unit is a unit that automatically sets a vector related to a moving direction of the position of the cross-sectional area with respect to the continuous imaging and automatically determines the position. Thereby, positioning can be performed by a simple operation.
[0017]
Further, as a preferred example, two-dimensional display means for two-dimensionally displaying the two-dimensional image, and mark display means for displaying a mark indicating the direction in which the two-dimensional image is observed in the three-dimensional space. And provided. Thereby, the support capability when determining the position of an imaging cross section increases.
[0018]
Further preferably, a designation unit that designates a slice direction for imaging the subject, and a plurality of two-dimensional images are obtained by continuously imaging the imaging target including the region of the subject along the slice direction. The image processing apparatus includes: a continuous imaging unit that generates; and a positioning image generation unit that generates a roughly three-dimensional positioning reference image of the imaging target from the plurality of two-dimensional images. For example, the positioning image generation means is means for extracting the contour of the imaging target from the plurality of images and generating the reference image from the contour data.
[0019]
Preferably, a signal detection means for detecting a signal representing physiological information of the subject, an imaging means for imaging an imaging target including the region of the subject as time elapses of the signal, Signal display means for displaying together with the signal a marker indicating at which timing of the signal the image captured by the imaging means corresponds, and the image display means displays the image displayed by the imaging means It may be a means for displaying in synchronization with the signal displayed by the signal display means. For example, the signal representing the physiological information of the subject is an ECG signal. Further, the signal display means and the image display means may be means that operate during reproduction while being imaged by the imaging means or after being imaged by the imaging means.
[0020]
Furthermore, as a preferred embodiment, an imaging unit that continuously images a plurality of parts including the region of the subject, and a locator that provides a plurality of locators using real-time images captured by the imaging unit Means. As an example, the region is a cross section, and the locator providing means provides a single cross section in which each locator is displayed by providing the image display means with a real-time image captured by the imaging means, and the cross section. , And another cross section to which the reference image is pasted.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, according to the present inventionMRI equipmentThe embodiment will be described with reference to the accompanying drawings.
[0023]
  (First embodiment)
  According to the first embodimentMRI equipmentThe basic feature is that an image of the cross section is displayed almost in real time while the cross section to be imaged in the three-dimensional space set for the subject is interactively three-dimensionally positioned. Specifically, this imaging method uses a technique called “intersecting two-section method” using a section to be imaged and a reference section that intersects the section.
[0025]
  Fig. 1 shows the MRI systemofConfiguration overviewTheShow.
[0026]
The MRI apparatus includes a substantially cylindrical static magnetic field magnet 1 installed in a gantry, and a gradient magnetic field coil 2 and an RF that are disposed around the subject P loosely inserted in the interior space of the magnet 1. A coil 3.
[0027]
The MRI apparatus further includes a gradient magnetic field power source 4 connected to the gradient coil 2, an RF generator 5 and a reception detector 6 connected to the RF coil 3. The gradient magnetic field power supply 4 sends a train of pulse currents corresponding to information on the pulse sequence of the gradient magnetic field provided from a sequence controller, which will be described later, to the gradient magnetic field coil (x, y, z coil) 2. The RF generator 5 generates an RF pulse current according to RF pulse sequence information given from a sequence controller described later, and supplies the RF pulse current to the RF coil 3.
[0028]
The MR signal generated in the subject is detected by the RF coil 3 and sent to the reception detector 6. The reception detection device 6 performs a predetermined reception process including detection on the received MR signal to convert it into digital MR data, and sends this to the arithmetic device 7. The arithmetic unit 7 is also part of the configuration of the MRI apparatus, and reconstructs the MR data in the frequency space that has been sent to generate image data in the real space.
[0029]
Further, the MRI apparatus is connected to the sequence controller 8 for controlling the gradient magnetic field power source 4, the RF generator 5, and the reception detector 6, and to the sequence controller 8 and the arithmetic unit 7 through the communication line 10. And a graphical user interface (GUI) 9 (hereinafter referred to as a user interface) for interactively displaying, editing, and analyzing processing between the user and the operator (user).
[0030]
The user interface 9 has a configuration in which a CPU 21, a memory 22, an input device 23, and a monitor 24 are connected to each other via a bus 25. The bus 25 is connected to the sequence controller 8 and the arithmetic unit 7 via the interface circuits 26 to 29 and the communication line 10.
[0032]
The CPU 21 executes various processes related to display, editing, and analysis described later between the user and the MRI apparatus main body. The memory 22 stores in advance a program necessary for the processing of the CPU 21 and can temporarily store necessary data being processed. The input device 23 is used by an operator to give necessary commands to the apparatus, and includes a mouse, a keyboard, and the like.
[0033]
The monitor 24 dynamically displays various images related to cross-section setting and various parameters and information for cross-section control. An example of this display screen is shown in FIG. As shown in the figure, the screen of the monitor 24 is a screen for providing a GUI function, and provides a display function, an editing function, and an analysis function in graphics. That is, this screen includes a captured image display window 400 that displays a currently collected image, a reference image display window 401 that displays a reference image, and a projection 3 that displays a projection position of a specified cross section in a three-dimensional absolute space. Various functions include a three-dimensional cross-section position display window 402 (hereinafter referred to as a cross-section position display window), a cross-section control edit window 403 for editing the rotation and shift of the cross section, a status display window 404 for displaying cross-section information, and the like. And a menu bar 405 that can be registered and used. These windows 401 to 404 form a positioning device (locator).
[0034]
The sequence controller 8 is configured to include computer elements such as a CPU and a memory in terms of hardware, and functionally, a data generation unit 201, a gradient magnetic field rotation unit 202, and a gradient magnetic field power supply control unit 203 by software processing. A frequency shift unit 205, an RF control unit 206, and a reception device control unit 208 (see FIG. 1).
[0035]
Using the position and viewpoint information of the section to be imaged (imaging section) designated by the operator, the control system rotates, moves, and enlarges / reduces the section, and MR images corresponding to the section are collected. When the operator inputs the position and viewpoint of the section to be imaged via the input device 23, the CPU 21 calculates the rotation enlargement / reduction and offset amount of the section corresponding to the information, and sends this to the sequence controller 8. The subsequent processing is left to the sequence controller 8.
[0036]
The sequence controller 8 receives the rotation, enlargement / reduction amount, and offset amount information sent from the user interface 9. In the sequence controller 8, the information is sent to the data generation unit 201 and converted into a rotation matrix and a frequency shift amount reflecting the information. In this rotation matrix generation process, a correction process by which a correction coefficient is applied is executed in order to correct enlargement / reduction and / or intensity variation between channels. The rotation matrix is sent to the gradient magnetic field rotation unit 202, and the offset amount is sent to the frequency shift unit 205.
[0037]
The gradient magnetic field rotating unit 202 converts the information of the rotation matrix sent to the corresponding control information, and sends this to the gradient magnetic field power supply control unit 203. The frequency shift unit 205 converts the transmitted offset amount into corresponding control information, and sends the control information to the RF control unit 206 and the reception device control unit 208. As a result, the gradient magnetic field power supply control unit 203 controls the pulse generation state of the gradient magnetic field power supply 4 according to the received control information and, for example, a pulse sequence of FE-based continuous imaging (fluoroscopy) specified in advance. Therefore, the gradient magnetic field strength superimposed on the static magnetic field is dynamically changed in real time. At the same time, the RF control unit 206 controls the RF pulse generation state of the RF generator 5 in accordance with the transmitted control information and a pre-designated pulse sequence of, for example, the FE system, so that the transmission RF The frequency of the pulse and its phase are dynamically changed in real time. As a result, as shown in, for example, US Pat. No. 4,830,012, an image of a specified cross-sectional region is almost realized in an asynchronous state in which both the timing change of the pulse sequence and the timing of image reconstruction are independent of data acquisition. MR continuous imaging (MR fluoroscopy) is performed in which images are continuously captured in time. Furthermore, the reception device control unit 208 changes the ADC detection frequency of the reception detection device 6 according to the transmitted control signal.
[0038]
In the present embodiment, the sequence controller 8, the arithmetic unit 7, the gradient magnetic field power supply 4, the RF generator 5, the reception detector 6, and an imaging unit capable of performing continuous imaging are configured.
[0039]
Note that an FE-based segmented EPI method or multi-shot EPI method may be used as a pulse sequence for continuous imaging (fluoroscopy).
[0040]
Thereby, the strength of the gradient magnetic field in each direction of slice, phase encoding, and readout generated from the gradient coil 2 is changed, and the frequency and phase of the transmission RF pulse transmitted from the RF coil 3 are changed. Accordingly, the cross-section to be imaged that is selectively excited is changed to an arbitrary position designated by the operator in substantially real time. The magnetic resonance signal due to the magnetization spin in the designated cross section is collected by the RF coil 3 as an echo signal and sent to the reception detector 6. The echo signal is subjected to a predetermined reception process by the reception detector 6 and is sent as echo data to the arithmetic unit 7 for reconfiguration processing or the like.
[0041]
On the other hand, an ECG sensor 41 attached to a subject P inserted into the gantry and an ECG unit 42 that inputs a sensor signal of the ECG sensor 41 and outputs an ECG signal are provided. This ECG detection means is provided as means for representing the cardiac cycle of the subject, but other detection means such as PPG may be used. This ECG signal is sent to the user interface 9 and taken into the CPU 21 via the interface circuit 29. The CPU 21 executes processing using the ECG signal as necessary.
[0042]
Hereinafter, examples of various display, editing, and analysis functions performed by the user interface 9 in this embodiment will be described.
[0043]
Here, the function of this user interface is suitable for use as a cross-sectional positioning device (locator) for imaging during continuous imaging (fluoroscopy). One or a plurality of functions may be selected and used in an appropriate order. Thus, for example, in imaging of a fast-moving heart part, a desired region of interest can be found out in a short time, and a cross section or volume region can be reliably set at that position.
[0044]
These functions are the following items a to s. When any of these items is instructed by the operator via the input device 23, the CPU 21 performs the following processing and presents it on the screen of the monitor 24 (see FIG. 3).
[0045]
a. Coordinate axis display and specified cross-section 3D display
When this function is activated, the three-dimensional physical (absolute) coordinate axis in the static magnetic field by the magnet 1 is displayed in the cross-section position display window 402, and the cross-section designated in the absolute three-dimensional coordinate space is shown as a cross section SEC1. As shown in FIG. Thereby, the positional relationship between the patient located in the bore of the magnet 1 and the cross section to be imaged is provided to the operator in an easily understandable manner. The position information of the designated cross section is transferred to the imaging means, and the part at the designated position is scanned almost in real time.
[0046]
b. Display of latest captured image and display of reference image
When this function is activated, the currently captured image is displayed in the captured image display window 400. The section of the specified cross section by the calculator 7ofEach time new image data is reconstructed, the image data is received and displayed on the window 400 as shown in FIG. For this reason, in the case of continuous imaging, the image displayed in the window 400 is updated almost in real time.
[0047]
In the reference image display window 401, the image selected as the reference image is displayed as shown in FIG. This reference image is a screen that is not updated until the next selection of the reference image.
[0048]
c. Paste the latest image to the specified section (watermarking)
With the activation of this function, the currently captured image is pasted on the cross section SEC1 displayed in the cross section position display window 402 as shown in FIG. This helps the operator to grasp the cross-sectional position three-dimensionally. The pasted image is preferably generated as a transparent image by watermark processing that can change the transparency of the image. As a result, objects existing behind the image are not hidden.
[0049]
d. Display reference section
By starting this function, another cross section (reference cross section) SEC2 presenting a reference image is displayed in the cross section position display window 402 as shown in FIG. This makes it easier to understand the positional relationship of the designated section SEC1 that is currently being imaged in the three-dimensional space within the subject. When a predetermined button on the menu bar 405 is clicked, the CPU 21 changes the current designated cross section (position) SEC1 to the reference cross section (position) SEC2 or processes to exchange them with each other. To do. This operation is very easy.
[0050]
e. Paste reference image to reference section (watermarking)
By activating this function, the reference image is pasted on the reference section SEC2. As a result, two-section images of the reference section SEC2 and the section SEC1 currently being imaged are displayed three-dimensionally in the section position display window 402 as shown in FIG. This two-section image makes it easier to grasp the three-dimensional position. At this time, preferably, one of the images located on the near side, such as a reference image, is processed into an image that is transparent in advance. This makes it possible to transparently observe the captured cross-sectional image and three-dimensional model image (when created and displayed as will be described later) located behind it.
[0051]
f. Section control (change of section position, change of display attribute)
As illustrated in FIG. 9, slide bar and buttons are presented in the cross-section control editing window 403, and the operation information is sent to the CPU 21 when the operator operates these operating bodies. Processing is executed. For this reason, the section control editing window 403 functionally provides means for instructing to change the position of the imaging section and means for instructing attribute change of the displayed image.
[0052]
In the case of this embodiment, a slide bar x, y, z that controls three-axis rotation of the imaging section, a slide bar offset that controls the center of rotation of the section, a slide bar zoom that controls enlargement / reduction, and 3 indicating the reference position. A check button ck for controlling the display / non-display of the dimension model, the coordinate axis, and the coordinate section is provided.
[0053]
A further feature of the cross-section control here relates to a method for instructing the three-axis rotation control of the designated cross-section (cross-section to be imaged) described above. As described above, the slide bars x, y, and z are provided for the three-axis rotation control. At the same time, as shown in FIG. 9, three circle bars A, B, and C, which are a kind of circular buttons, are provided. Is provided just above the slide bars x, y, z. Each of the circle bars A, B, and C corresponds to each of the three parameters of the three-axis rotation, and provides a rotation parameter that returns to 360 degrees. The values of the parameters set at that time are shown in real time inside the circles of the circle bars A, B, and C. When changing parameters, move the mouse pointer to each circle bar and click the left mouse button, for example. The angle formed between the clicked position and the radial line segment passing through the center point and a predetermined reference line forms a parameter value. This value is displayed in real time as a numerical value. As another method of parameter specification, the left mouse button can be held, and the parameter can be continuously changed by rotating the mouse pointer placed in the circle bar around the center. As described above, by using the circle bar to control the three rotation angles of the cross section to be imaged, an easier operation method can be provided. This circle bar can also be suitably used in controlling the viewpoint position according to the next g term.
[0054]
g. Section control (change of viewpoint position)
The section control editing window 403 provides means for easily changing the position of the viewpoint for observing the absolute coordinate axis as shown in FIG. As a result, the operator's line of sight observing the specified cross section (the cross section to be imaged) can be freely moved, and a state in which the operator confirms the cross-sectional position while moving around the subject can be virtually obtained. . This changing means includes a circle bar, a slide bar, and a CPU for operating the rotational coordinate system (φ, θ, r) of the viewpoint vector. Two parameters of the angle component of the viewpoint can be easily changed by the circle bar.
[0055]
h. Specifying the position on the image
It has a function of designating a position with an input device such as a mouse pointer on the image generated by the changing means described above. When this function is activated, the spatial position corresponding to the designated position is displayed as a point or line segment MK on the screen of the cross-section position display window 402 and in a hue different from the image (see FIG. 11). Since the display body by these points or line segments MK is fixedly displayed in the space even if the cross-sectional position is changed, and a plurality of display bodies can be displayed, it can be used as a marker. These markers are stored in a state where they can be edited (deleted, changed in attributes), and can be called at any time. Furthermore, a function that can move the designated cross section to the position of the marker is also added. In particular, in the case of a linear marker, the marker is moved so as to coincide with the axis in the cross section.
[0056]
i. Providing the reference position of the specified cross section
When this function is activated, a three-dimensional model of an object or an actual rendering three-dimensional image based on a captured image is displayed superimposed on the cross-section position display window 402, and the reference position of the designated cross-section (the cross-section to be imaged) is displayed. Provided to the operator. A rendering three-dimensional image can also be constructed by directly using an image captured by shifting the cross-sectional position. Further, in connection with this, the marker position placed by the operator on the above-described cross section is connected, and a function of rendering the object with polygons is also provided.
[0057]
j. Memory of display cross section position and return to memory position
This function provides means for recording the cross-sectional position displayed at an arbitrary time (see FIG. 12) and returning to the recorded position. This means includes a CPU 21 and a memory 22. In this stored information, a captured image captured at the recorded cross-sectional position and a reduced view of the image of the cross-sectional position display window 402 are presented as icons.
[0058]
k. Description of absolute position of specified section
The specified cross-section (the cross-section to be imaged) has an absolute position described with few parameters such as an enlargement factor, a movement vector, and Euler angle. As a result, the amount of data handled can be reduced.
[0059]
l. Specifying the section to be imaged
With this function, as means for the operator to specify the imaging section at the desired position, means for specifying the section position by Euler angle and means for specifying by rotation around the two rotation axes and the section orthogonal axis in the section are provided. Is done. The latter designation means is a designation method depending on the order of rotation, but the former designation means is uniquely determined with respect to rotation. These rotational sections can be displayed continuously with respect to one another.
[0060]
m. Gaze arrow display
By activating this function, an arrow AR indicating from which direction the image of the imaging section display window 400 is viewed is displayed in the section position display window 402 (see FIG. 13). Also, by inverting the image, a means for viewing the image from the opposite direction is also provided, and simultaneously with the inverting, the position of the arrow AR is attached to the opposite side of the cross section. As the display position in the window 402, a position such as the upper left is automatically selected, and the operator is quickly provided with the positional relationship between the screen and the cross section.
[0061]
A means for displaying the same arrow independently from the window 402 is also provided for the reference image display window 401. In this case, it is desirable to change the display color between the windows 401 and 402 so that the double arrows can be easily identified.
[0062]
n. Show / hide projected 3D display
With this function, display and non-display of the image displayed in the cross-section position display window 402 can be easily controlled from the cross-section control edit window 403. Thereby, overlapping of images in the window 402 can be avoided.
[0063]
o. Dynamic planning (macro function)
This feature allows a series of dynamic planning. This planning is realized by a macro function that describes a movement amount and a rotation angle as a function of time. As a result, a stylized cross-sectional shift or an omnidirectional rotation image at a certain position can be obtained by a simple operation. The operator can describe and register a desired procedure.
[0064]
p. Continuous scan using parameters
When this function is used, as shown in FIG. 14, a cylindrical object can be continuously scanned with few parameters by adding three translational degrees of freedom to three translational degrees of freedom and three degrees of freedom of rotation. These parameters may be continuously changed by the macro function described above. For example, as shown in FIG. 14, the fixed coordinate system xyz is translated by an amount that can be represented by a vector r0, then rotated by the coordinate system x′y′z ′, and further translated by an amount that can be represented by a vector r1. By continuously changing the rotation angle, cross sections such as s0, s1, and s2 can be obtained continuously. This method is suitable for continuously imaging a wall such as the heart. Further, by configuring the vector r1 to be automatically extracted from the image of the orthogonal cross section being processed, it is possible to capture the image of each cross section while automatically tracking the cross section around the heart wall.
[0065]
q. Continuous cross-sectional position recording and playback
This is a function of continuously recording and reproducing the cross-sectional position. In addition, this function includes a function capable of stopping recording during reproduction and recording by changing the cross-sectional position from the stopping position. At the time of reproducing the recorded information, the recorded position information of the cross section is sent to the control system as in the normal operation, and the image is automatically collected almost in real time.
[0066]
r. Enlarging / reducing function
With this enlargement / reduction function, the intensity of the gradient magnetic field and the state of the RF signal can be changed at an arbitrary time, and the ROI can be enlarged or reduced to a desired size.
[0067]
s. Automatic average operation
With this function, if the same position in the three-dimensional space is traced over a small range, the collected image is automatically averaged to improve the image quality.
[0068]
By appropriately selecting these various interface functions a to s and using them in an appropriate order, for example, in imaging of a fast-moving heart part, the operator can quickly find a desired region of interest while viewing the screen. Find and set a cross-section or volume area reliably at that location.
[0069]
In the above-described embodiment, the case of an MRI apparatus that performs continuous imaging has been described. However, the MRI apparatus may be used as an input device for specifying a cross-sectional position in MPR (cross-section conversion) processing of the MRI apparatus.
[0070]
For example, as shown in FIG. 15, when an operator inputs a cross-sectional position and a viewpoint position to be captured (step 100), the information is sent to a modality (image collection device), and the corresponding cross-sectional image and position are displayed. Information is obtained (step 101). The cross-sectional position and the viewpoint information are converted into a position in a three-dimensional space (step 102), and a projected three-dimensional image is calculated by MPR from three-dimensional image data collected in advance (step 103). This projected three-dimensional image is pasted on the cross section at the designated position viewed from the viewpoint (step 104), and is projected and displayed three-dimensionally (step 105). A two-dimensional image captured in parallel with this is also displayed (step 106). As a result, two types of images, that is, a two-dimensional image of the designated cross-sectional position and a projected three-dimensional image are displayed. By observing these images, it is easy to spatially grasp the cross-section to be imaged, and positioning the cross-section Can be performed easily and accurately.
[0071]
MPR three-dimensional image data may be provided on the MRI apparatus side or on the interface side. Further, the three-dimensional image data may be configured to use data collected by another type of modality such as a three-dimensional ultrasonic diagnostic apparatus.
[0072]
The gist of the present invention is not limited to the above-described embodiments and modifications, and those skilled in the art can further appropriately combine, change, and modify within the scope of the basic principle of the present invention. Yes, they can also be regarded as the invention and scope of the claims. For example, in terms of the above items, only the functions of the items a to c, e to h, m, and o to q may be combined.
[0073]
Further, FIG. 16 shows a function t that can be added to the items a to s described above. When this function t is activated, a substantially cylindrical three-dimensional body SY that schematically represents the static magnetic field space in the gantry is displayed when the designated section SEC1 and the reference section SEC2 related to the intersecting two-section method are displayed. The state in which the designated cross section SEC1 and the reference cross section SEC2 intersecting with the magnetic field center inside is positioned is displayed three-dimensionally. For example, the three-dimensional body SY and the two cross sections SEC1 and SEC2 are displayed with different color tones and projected. This image is displayed in the cross-section position display window 402. This helps to more easily grasp the positional relationship in the static magnetic field between the two cross sections SEC1 and SEC2.
[0074]
(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIGS.
[0075]
  According to the embodiment described aboveMRI equipmentAs one of the usage forms, there is a state in which a three-dimensional rendering image to be imaged is placed at the center of the coordinate axis and the inside thereof is positioned. However, a problem when performing this positioning is that it takes time to collect the three-dimensional image data to be imaged. The present embodiment improves such a situation.
[0076]
  According to the second embodimentMRI equipmentIt has a function of positioning a three-dimensional image at the coordinate center of the static magnetic field. This function is realized by software processing of the CPU 21, and its outline is shown in FIG.
[0077]
As shown in FIG. 17, the CPU 21 designates the slice direction DS of the imaging target OB based on, for example, operation information given from the input device 23 or automatically set information (step S31: see FIG. 18). Next, the CPU 21 instructs the imaging means to perform two-dimensional imaging (or continuous imaging) along the slice direction DS, and receives a two-dimensional image IM obtained as a result (steps S32 and S33). Then, the contour CT of the imaging target OB is extracted from the two-dimensional image IM (see step S34: FIG. 19). This series of processing is performed by a two-dimensional image IM (for example, IM₁~ IM₅: See FIG. 19) for a predetermined number of sheets (step S35). When this is completed, the CPU 21 uses the contour CT data of each 2D image IM to obtain a simple 3D image IM._simIs created (step S36). This creation processing uses, for example, MIP processing or volume rendering processing as long as the data processing time does not become extremely long. A simple three-dimensional image IM of the imaging target OB obtained in this way_simIs placed as a reference image at the coordinate center position as shown in FIG. 20 (step S37).
[0078]
This simple 3D image IM_simThe spatial position of the designated cross section is grasped from the relationship between the reference image based on the above and the position of the designated cross section for positioning. For this reason, the designated cross section can be positioned at a desired position, and an image of the cross section can be observed in real time as in the above-described embodiment.
[0079]
Thus, a simple three-dimensional image IM from a two-dimensional image continuously captured while slicing in a certain direction._simTherefore, the three-dimensional reference image of the imaging target OB can be obtained in a shorter time than when the imaging target OB is properly three-dimensionally scanned. Since this three-dimensional reference image is intended for positioning, an image created in this way is sufficient. As a result, the three-dimensional reference image IM_simWith the positioning using the designated cross section, the designated cross section position can be grasped more intuitively, and quick and accurate imaging can be performed.
[0080]
  (Third embodiment)
  According to this third embodimentMRI equipmentWill be described with reference to FIGS. This embodiment relates to an image display obtained by electrocardiographic synchronization mode imaging.
[0081]
  As described above, according to the first embodimentMRI equipmentTherefore, a method of using the region of interest while observing the three-dimensional position in the subject in real time is preferable. When this method is applied to a periodically moving organ such as the heart, it is necessary to perform positioning and observation at a high frame rate of several frames to several tens of frames per second. However, doing so sacrifices spatial resolution. . Therefore, once positioning is completed, an electrocardiographic synchronization method is used to switch to an imaging method with increased spatial resolution. However, there is a situation in which observation and diagnosis are hindered because it is not clear to which time phase of the electrocardiogram waveform each image corresponds to when the captured image is displayed simply by switching. The present embodiment improves such a situation.
[0082]
Specifically, the CPU 21 performs processing schematically shown in FIG. When a higher resolution image is required after positioning, the CPU 21 inputs an ECG signal, and determines whether or not the delay time from the R wave in the signal is a predetermined value that is updated in predetermined increments (for example, 100 msec). Judgment is made (steps S41 and S42). If the determination is YES, it is recognized that the delay time from the R wave has reached the ECG synchronization timing extended by, for example, 100 msec. Therefore, the CPU 21 instructs the imaging unit to perform imaging with higher resolution than before (step S43).
[0083]
In parallel with this high-resolution imaging, the CPU 21 instructs display processing (steps S44 to S46). That is, the two-dimensional image IM input from the computing unit 7 is received, and the synchronization timing (delay time) of the two-dimensional image IM is specified (step S44). Further, the data of the marker M is superimposed on the position corresponding to the synchronization timing on the ECG waveform data (step S45). Furthermore, the CPU 21 displays the ECG waveform on which the marker M is superimposed and the two-dimensional image IM on the monitor 24 in synchronization (step S46).
[0084]
As a result, as shown in FIG. 22, the captured image display window 400 formed on the screen of the monitor 24 has a two-dimensional image IM (IM₁~ IM₅) Is updated and displayed as time t elapses. In parallel with this, an ECG waveform is displayed with the passage of time t in the physiological information display window 406 formed on the same screen. A marker M is also superimposed on the ECG waveform at every synchronization timing. That is, the ECG waveform and its marker M are also updated in synchronization with the update of the image IM. The marker M corresponding to the imaging time of the currently displayed two-dimensional image IM is displayed with different brightness (or hue) from the past marker, for example. For example, in the example of FIG. 22, the currently displayed two-dimensional image IM₅The imaging timing is the time represented by the marker M ′ on the ECG waveform.
[0085]
In the above embodiment, the ECG waveform is synchronously displayed together with the collection of image data at the time of imaging, but the ECG waveform may be synchronously displayed when the image is reproduced after the imaging is completed.
[0086]
Thereby, even in the case of imaging using the electrocardiogram synchronization method, it becomes clear at a glance which time phase of the electrocardiogram waveform the displayed (or reproduced) image is.
[0087]
Note that the ECG waveform with the marker may be superimposed on the captured image display window 400.
[0088]
In this embodiment, the ECG signal is detected together with the imaging and the both are synchronously displayed. However, instead of such a signal, it depends on an electrocardiographic waveform based on pulse wave synchronization PPG (peripheral gating) and respiratory synchronization. The waveform may represent a physiological information such as a waveform.
[0089]
This MRI apparatus can also be applied to functional MRI (fMRI). In fMRI, a stimulus (input stimulus) such as light, sound, air, and electricity is given to a subject, and images and data reflecting the response state to the stimulus are collected. For this reason, such an input stimulus waveform is displayed in the physiological information display window 406 described above, and an image or data curve as an output is displayed in the captured image display window 400 in synchronization therewith.
[0090]
This method can also be applied to temperature measurement. For example, when a temperature curve in a region of interest of a real-time image obtained by continuous imaging is obtained by applying warming energy by a laser for treatment, a rectangular waveform indicating on / off of the laser output is displayed in the physiological information display window 406. Are displayed in the captured image display window 400 respectively.
[0091]
  (Fourth embodiment)
  According to this fourth embodimentMRI equipmentWill be described with reference to FIGS. This embodiment shows an example in which a plurality of locators (positioning devices) are mounted.
[0092]
  For each of the embodiments described aboveMRI equipmentBoth have described a configuration in which one locator is mounted. However, when observing a plurality of anatomically complex structures simultaneously, such as when observing a dissecting aorta, a single locator may not be sufficient. This embodiment improves this.
[0093]
Specifically, the screen presented on the monitor 24 by the user interface 9 includes a set of the captured image display window 400A and the reference image display window 401A formed in the same manner as described above, as shown in FIG. A set of captured image display window 400B and reference image display window 401B are formed. In either set, the captured image display window displays images collected by continuous imaging of the specified section (the section to be captured), while the reference image display window displays an image of an appropriate reference section. Is done.
[0094]
In the present embodiment, real-time images of two places displayed on both the captured image display windows 400A and 400B are alternately captured by one imaging unit, for example. For this reason, although the display rate for each one window is lower than when only one window is provided, it is possible to perform real-time imaging of different places.
[0095]
Accordingly, in the cross-section position display window 402, one locator (1): LC1 based on the cross-section 2 cross-section method with the designated cross-section SEC1A and the reference cross-section SEC2A is used. The other locator (2) based on: LC2 is formed respectively.
[0096]
The CPU 21 performs switching control shown in FIG. 24 for these two locators (1) and (2). The CPU 21 determines from the operation information whether or not to activate the locator (1) based on the real-time image (1) displayed on the one captured image display window 400A. If YES, the locator (1) is determined. On the contrary, the locator (2) based on the real-time image (2) displayed on the other captured image display window 400B is paused (steps S51 and S52). Subsequently, whether or not to activate the locator (2) is determined from the operation information. If YES, the locator (2) is activated and, on the contrary, the locator (1) to be relied upon is paused (steps S53 and S54). ).
[0097]
By repeating this series of switching processes, for example, every minute fixed time Δt, both locators (1) and (2) can be switched at an arbitrary timing. For example, when observing a site of a complicated structure such as a dissecting aorta, first, one locator (1) performs positioning (cross-section setting) of a desired location interactively, and then the other Similarly, the positioning (cross-section setting) of another place is performed interactively by the locator (2). Therefore, different locations can be observed in real time almost simultaneously with the images of the cross sections SEC1A and SEC1B determined by both locators (1) and (2).
[0098]
In the above-described embodiment, three or more sets based on the real-time image and the reference image may be provided to configure three or more locator units. In the above-described embodiment, the locators (1) and (2) are switched and used. However, a plurality of windows 402 may be provided independently and used independently.
[0099]
  In the above second to fourth embodimentsMRI equipmentAs a result, it is possible to perform the real-time positioning and the observation of the cross-section of the positioning section with respect to the three-dimensional data to be imaged at higher speed, easier to understand the positional relationship, and in an interactive real time.
[0100]
Although the present embodiment is as described above, the present invention is not limited to the configuration described in the above-described embodiment, and those skilled in the art will further appropriately perform the present invention without departing from the gist described in the claims. Various modified and modified configurations can be realized, and these configurations are also included in the present invention.
[0101]
【The invention's effect】
  As explained above, the present inventionAccording to the MRI apparatus related toFor example, continuous imagingInFor positioning of imaging area (cross-sectional area, etc.)LeaveWhile accurately recognizing the spatial positional relationship between the subject and the area to be imaged, the area (cross section, etc.) to be imaged can be set quickly and accurately and easily at a desired three-dimensional position, and the image of the imaging area Can be displayed in real time, and can be provided for observation and a novel positioning and image display method can be provided.
[Brief description of the drawings]
FIG. 1 relates to an embodiment of the present invention.MRI equipmentFIG.
FIG. 2 is a diagram showing a screen configuration of a graphical user interface according to the first embodiment.
FIG. 3 is a diagram illustrating various functions of a graphical user interface.
FIG. 4 is a diagram illustrating one function of a graphical user interface.
FIG. 5 is a diagram illustrating another function of the graphical user interface.
FIG. 6 is a diagram illustrating still another function of the graphical user interface.
FIG. 7 is a diagram illustrating still another function of the graphical user interface.
FIG. 8 is a diagram illustrating still another function of the graphical user interface.
FIG. 9 is a diagram illustrating still another function of the graphical user interface.
FIG. 10 is a diagram illustrating still another function of the graphical user interface.
FIG. 11 is a diagram illustrating still another function of the graphical user interface.
FIG. 12 is a diagram illustrating still another function of the graphical user interface.
FIG. 13 is a diagram illustrating still another function of the graphical user interface.
FIG. 14 is a diagram for explaining one of cross-section position designation methods in a three-dimensional space.
FIG. 15 is a schematic flowchart of processing showing an example used for MRR processing;
FIG. 16 is a diagram illustrating another function of the graphical user interface.
FIG. 17 is a schematic flowchart showing the processing of a CPU implemented in the second embodiment.
FIG. 18 is a diagram of two-dimensional scans performed a plurality of times along a designated slice direction, explaining generation of a simple 3D image.
FIG. 19 is a diagram illustrating a two-dimensional image captured by a plurality of two-dimensional scans along a designated slice direction.
FIG. 20 is a diagram illustrating a state in which a simple 3D image is displayed as a reference image.
FIG. 21 is a schematic flowchart showing the processing of a CPU implemented in the third embodiment.
FIG. 22 is a diagram for explaining synchronous display of an ECG waveform with a marker and an MR image.
FIG. 23 is a view for explaining two positioning devices (locators) realized by software processing according to the fourth embodiment.
FIG. 24 is a schematic flowchart for explaining the switching operation of two locators.
[Explanation of symbols]
1 Magnet
2 Gradient coil unit
3 RF coil
4 Gradient magnetic field power supply
5 RF generator
6 reception detector
7 Arithmetic unit
8 Sequence controller
9 Graphical user interface
10 Communication line
21 CPU
22 memory
23 Input device
24 Monitor
P subject

Claims (19)

Area display means for displaying at least one cross-sectional area placed in a three-dimensional space set for the subject;
Image display means for displaying an image of a portion corresponding to the cross-sectional area of the subject in the cross- sectional area;
Changing means for arbitrarily changing at least one of the direction and position of the cross-sectional area in the three-dimensional space ;
An imaging means that obtains at least two two-dimensional images by continuously imaging (fluoroscopy) a portion of the subject corresponding to the cross-sectional area ;
The MRI apparatus, wherein the image display unit includes a pasting unit that sequentially pastes the two-dimensional image updated corresponding to the cross-sectional area to the cross-sectional area displayed on the area display unit . 2. The MRI apparatus according to claim 1, wherein the area display means is a means for displaying both the cross-sectional area and a three-dimensional absolute coordinate axis set in the three-dimensional space. 2. The MRI according to claim 1, further comprising: a reference image display unit that pastes the two-dimensional image captured at an arbitrary time by the imaging unit as a reference image in another cross-sectional area placed in the three-dimensional space. Equipment . The MRI apparatus according to claim 1, further comprising: designation means for designating a position in the three-dimensional space; and marker display means for displaying a marker corresponding to the designated position on the three-dimensional space. The MRI apparatus according to claim 4, wherein the marker display unit is a unit that displays the marker in a hue different from that of the two-dimensional image. The MRI apparatus according to claim 2, wherein the position changing unit is a unit that designates a desired three-dimensional position by moving, rotating, and moving the cross-sectional area. The MRI apparatus according to claim 1, further comprising recording / calling means for recording a three-dimensional position of the area in the three-dimensional space in time series and calling the recorded three-dimensional position. 8. The MRI apparatus according to claim 7, further comprising reproduction means for reproducing the two-dimensional image corresponding to the called three-dimensional position in time series. The MRI apparatus according to claim 2, wherein the position changing unit is a unit that changes a position of the cross-sectional area with respect to the continuous imaging by a reserved routine operation. The MRI apparatus according to claim 9, wherein the routine operation uses a macro description method using a function of time as a method of designating a movement amount of the cross-sectional area. The MRI according to claim 9, wherein the position changing unit is a unit that automatically sets a vector related to a moving direction of the position of the cross-sectional area with respect to the continuous imaging and automatically determines the position by image processing. Equipment . And 2-dimensional display means for displaying the 2-dimensional images in two dimensions, according to claim 2 in which a and mark display means for displaying a mark indicating a direction in which to observe the two-dimensional image on the three-dimensional space The MRI apparatus according to 1 . Designation means for designating a slice direction for imaging the subject; and continuous imaging means for generating a plurality of two-dimensional images by continuously imaging an imaging target including the region of the subject along the slice direction; 2. The MRI apparatus according to claim 1, further comprising: a positioning image generation unit configured to generate a substantially three-dimensional positioning reference image of the imaging target from the plurality of two-dimensional images. The MRI apparatus according to claim 13, wherein the positioning image generation unit is a unit that extracts a contour of the imaging target from the plurality of images and generates the reference image from the contour data. Signal detection means for detecting a signal representing physiological information of the subject, imaging means for imaging an imaging target including the region of the subject as time elapses of the signal, and imaged by the imaging means Signal display means for displaying together with the signal a marker indicating at which timing of the signal the image to correspond to,
The MRI apparatus according to claim 1, wherein the image display unit is a unit that displays an image displayed by the imaging unit in synchronization with a signal displayed by the signal display unit . The MRI apparatus according to claim 15, wherein the signal representing physiological information of the subject is an ECG signal. The MRI apparatus according to claim 15, wherein the signal display means and the image display means are means that operate during reproduction after being imaged by the imaging means or after being imaged by the imaging means. Imaging means for successively imaging the plurality of portions including the area of the subject, according to claim 1 comprising a locator provided means for providing a plurality of locator using an image of the real time captured by the image pickup means The MRI apparatus according to 1 . The region is a cross-section;
The locator providing means is configured such that each locator crosses the cross section and pastes a reference image, which is displayed by giving the image display means the real time image picked up by the image pickup means. The MRI apparatus according to claim 18, comprising a single cross section.

Images