JP2004008398A - Medical image diagnostic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To display an access start position, and an intended position and direction in a real space when one is making an internal access to a living body with a treatment instrument such as a puncturing needle. <P>SOLUTION: A plurality of tomographic images captured from at least biaxial directions from among orthogonal triaxial directions of an examinee 1 are displayed with a medical image diagnostic apparatus capable of imaging and displaying a tomographic image in an optional section of the examinee 1 and an arbitrary position showing a target position such as a tumor is selected by using the plurality of tomographic images. A coordinate position in the real space is calculated from the selected arbitrary position. Laser light emitted from an x-direction display laser 21x, a y-direction display laser 21y and a z-direction display laser 21z controls the irradiation position and direction of each laser light so as to ensure that the calculated coordinate position is indicated. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a medical image diagnostic apparatus, and more particularly to a technique for assisting an operator with a start position, a target position, and a direction of access to a living body by a treatment tool such as a puncture needle.
[0002]
[Prior art]
2. Description of the Related Art A magnetic resonance imaging apparatus (referred to as an MRI apparatus) measures a nuclear spin density distribution, a relaxation time distribution, and the like at a desired examination site in a subject using a nuclear magnetic resonance (abbreviated as NMR) phenomenon. An arbitrary cross section of the subject is displayed as an image from the measurement data.
[0003]
The imaging sequence in the MRI apparatus includes, in addition to a basic imaging sequence such as a spin echo method and a gradient method, an echo planar (EPI: Echo Planar Imaging) method, a fast spin echo (FSE: Fast Spin Echo) method, and the like. A faster imaging sequence is known.
[0004]
As one of applications of these high-speed imaging sequences, a real-time dynamic imaging method called fluoroscopy (fluoroscopic imaging) is being clinically applied. In fluoroscopy, dynamic imaging of a body tissue is generated and displayed as if by X-ray fluoroscopy by repeating imaging and image reconstruction at a cycle of about 1 second or less. Recently, such fluoroscopy is being applied to intraoperative imaging, which is collectively referred to as interventional MRI (hereinafter, referred to as “I-MRI”) for the purpose of minimum invasiveness (Minimum Invasive). is there.
[0005]
The most promising use of fluoroscopy in I-MRI is monitoring when a puncture needle or catheter is guided to an affected area. The flow up to the start of treatment during an operation using a medical image diagnostic apparatus in such an I-MRI will be described. As shown in FIG. 8, imaging by the medical image diagnostic apparatus (step 401) and a target (such as a tumor) by the image are performed. (Step 402), perform a procedure (puncture, incision, etc.) in accordance with the purpose (Step S403), and confirm that an appropriate procedure has been performed (successful access to the target). The imaging was performed twice (step S404). Further, the above contents for a plurality of purposes are repeatedly performed (step S404), and the operation is performed while grasping the positional relationship of each.
[0006]
On the other hand, in cardiac imaging using an MRI apparatus, puncture monitoring at the time of surgery, and the like, there is a demand for arbitrarily setting an imaging section in real time, and technical development for this is being performed. As a technique for arbitrarily setting an imaging section, there is an example in which an MRI image is displayed, and a button on the screen is clicked to use a graphical user interface (GUI) for determining a next imaging section. (Magnetic Resonance in Medicine: Real-time interactive MRI on a conventional scanner; AB. Kerr et al., Vol. 38, pp. 355-367 (1997)), and a method using a three-dimensional mouse (USP-55112827).
[0007]
Further, there has been proposed an apparatus for determining an imaging section of an MRI apparatus using a position determining device. (USP-5365927: MRI apparatus is photographed using information from a position sensor), (USP-6026315: A photographed section is determined using a pointer composed of two infrared cameras and three reflecting spheres).
[0008]
An open type MRI apparatus is used for I-MRI used for surgery, puncture, and percutaneous treatment. Open MRI includes a double donut type, a C type, and an asymmetric two-post type. The double donut type has a structure in which two donut magnets that generate a horizontal magnetic field are arranged with a gap therebetween, and an image of an object is taken between the gaps. The most open type is an asymmetric two-post type, which can be accessed from three directions, that is, the left and right direction of the subject and the parietal side.
[0009]
When a patient is set on an MRI apparatus, a target portion is generally arranged at the center of a static magnetic field, and a method of displaying the position of the center of the static magnetic field includes a method of indicating the position using irradiation light from a projector. Irradiation light can be irradiated from three directions, and the position of the patient can be adjusted while visually observing irradiation light from three axial directions.
[0010]
[Problems to be solved by the invention]
However, the above-described method of arbitrarily selecting an imaging cross section has a merit that, although there is an advantage that an arbitrary imaging cross section can be drawn in real time, means for rapidly and accurately drawing a puncture start position, a target position, and a puncture direction. Because of the lack of treatment, it took an excessive amount of time to start treatment, placing a burden on the surgeon and the subject. In addition, since the exact direction is not known even during puncturing, puncturing may have been performed at a position deviated from a target portion due to an error (re-puncturing was necessary).
[0011]
Further, the irradiation light from the conventional projector is for indicating the position of the center of the magnetic field and the like.Since it is impossible to arbitrarily move the installation place of the projector, it is not used for the purpose of indicating an arbitrary position or direction. Had not been used.
[0012]
The present invention has been made in view of such circumstances, and displays an access start position, a target position, and a direction in a real space when accessing a living body with a treatment tool such as a puncture needle in a real space to assist an operator. It is an object of the present invention to provide a medical image diagnostic apparatus capable of performing the above.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 is a medical image diagnostic apparatus capable of capturing and displaying a cross-sectional image at an arbitrary cross-section of a subject. Display means for displaying a plurality of cross-sectional images taken from different directions, a selecting means for selecting an arbitrary position indicating the same site using the plurality of cross-sectional images, and an arbitrary position selected by the selecting means Calculating means for calculating a coordinate position of the position in the real space; light display means for irradiating the subject with a plurality of light beams; and the plurality of light beams defining the coordinate position based on the calculated coordinate position. Control means for controlling the light display means as indicated.
[0014]
That is, a plurality of cross-sectional images obtained by imaging the subject from at least two of the orthogonal three-axis directions are displayed on the display unit, and the plurality of cross-sectional images are used to display the same site (for example, a target such as a tumor). ) Is selected. From the arbitrary position selected in this way, the coordinate position of the position in the real space is calculated. Then, when irradiating the subject with a plurality of light beams from the light display means, by controlling the irradiation position and direction of the light beam, the calculated coordinate position is indicated by each light beam irradiated on the subject. Like that.
[0015]
In the selection means, an arbitrary position can be selected by moving or tilting a target line (solid line or broken line) for determining an imaging section displayed in the screen of the plurality of section images. . The coordinate position in the real space of the arbitrary position thus selected is automatically calculated and added to the control means in real time. The control means controls the light display means based on the coordinate position applied in real time, and moves the position indicated by the plurality of light beams emitted from the light display means.
[0016]
The light display means emits light harmless to the human body, such as a light emitting diode or a He-Ne laser, and has a function of turning on / off the light emission.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the medical image diagnostic apparatus according to the present invention will be described in detail with reference to the accompanying drawings.
[0018]
FIG. 1 is a schematic diagram showing the overall configuration of a medical image diagnostic apparatus according to the present invention, and particularly shows an MRI apparatus.
[0019]
An MRI apparatus measures the density distribution and relaxation time distribution of nuclear spins at a desired inspection site in a subject using the NMR phenomenon, and displays an arbitrary cross section of the subject from the measurement result as an image. It comprises a static magnetic field generating magnet 2, a gradient magnetic field generating system 3, a transmitting system 5, a receiving system 6, a signal processing system 7, a central processing unit (CPU) 8, and an optical display 21.
[0020]
The static magnetic field generating magnet 2 generates a uniform static magnetic field around the subject 1 in a body axis direction or a direction perpendicular to the body axis, and is a permanent magnet type, a normal conduction type, or a superconducting type magnetic field generating means. Consists of In the magnetic field space surrounded by the static magnetic field generating magnet 2, a gradient magnetic field coil 9 of the gradient magnetic field generating system 3, a high frequency coil 14a of the transmitting system 5, and a high frequency coil 14b of the receiving system 6, which will be described later, are installed.
[0021]
The gradient magnetic field generation system 3 includes a gradient magnetic field coil 9 wound in three directions of X, Y and Z, and a gradient magnetic field power supply 10 for driving the respective gradient magnetic field coils 9. By driving the gradient magnetic field power supplies 10 of the respective coils in accordance with the following formulas, gradient magnetic fields Gx, Gy, Gz in the three axes of X, Y, and Z are applied to the subject 1. The slice plane for the subject can be set by how to apply the gradient magnetic field.
[0022]
The sequencer 4 repeatedly applies a high-frequency magnetic field pulse that causes nuclear magnetic resonance to the nuclei of the atoms constituting the living tissue of the subject 1 in a predetermined pulse sequence. Various commands necessary for data collection of the tomographic image are transmitted to the transmission system 5, the gradient magnetic field generation system 3 and the reception system 6.
[0023]
The transmission system 5 irradiates a high-frequency magnetic field for causing the nuclei of the atoms constituting the living tissue of the subject 1 to undergo NMR under the control of the sequencer 4, and includes a high-frequency oscillator 11, a modulator 12, and a high-frequency amplifier. 13 and a transmitting high-frequency coil 14a. The high-frequency pulse output from the high-frequency oscillator 11 is amplitude-modulated by the modulator 12 in accordance with a command of the sequencer 4, and the high-frequency pulse subjected to the amplitude modulation is amplified by the high-frequency amplifier 13, and thereafter, the high-frequency pulse is disposed close to the subject 1. By supplying the electromagnetic wave to the coil 14a, the subject 1 is irradiated with the electromagnetic wave.
[0024]
The receiving system 6 detects an echo signal (NMR signal) emitted from the subject 1 by NMR of atomic nuclei of a living tissue, and includes a receiving-side high-frequency coil 14b disposed in close proximity to the subject 1 and an amplifier. 15, a quadrature detector 16, and an A / D converter 17. The echo signal detected by the high-frequency coil 14b on the receiving side is input to an A / D converter 17 via an amplifier 15 and a quadrature detector 16 and converted into a digital signal amount. The data is collected as two series of data sampled by the quadrature phase detector 16, and the signal is sent to the signal processing system 7.
[0025]
The signal processing system 7 includes a CPU 8, a recording device such as a magnetic disk 18 and a magnetic tape 19, and a display 20 such as a CRT. The signal from the receiving system 6 is subjected to Fourier transform, correction coefficient calculation, image reconstruction by the CPU 8. Is performed, and a signal intensity distribution of an arbitrary section or a distribution obtained by performing an appropriate operation on a plurality of signals is imaged and displayed on the display 20.
[0026]
Further, in the MRI apparatus, the signal processing system 7 has a function of performing difference processing and weighting on image data as functions of the CPU 8. These processes are performed on data obtained by performing measurement in the MRI apparatus. Means for selecting and setting these processes are provided as input means of the CPU 8. Further, the display 20 has a function of displaying a difference image or a cumulatively added image instead of or in addition to a normal image in accordance with the function of the signal processing system 7.
[0027]
Next, the optical display 21 according to the present invention will be described.
[0028]
The light indicator 21 indicates a predetermined portion (for example, a target such as a tumor) in the subject by a plurality of laser irradiation lights, and indicates a puncturing start position, a target position, and a direction when the puncture needle punctures the living body. These are displayed in real space, and as shown in FIG. 2, an x-direction display laser 21x such as a He-Ne laser, a pair of y-direction display lasers 21y, and a pair of z-direction display lasers 21z, Moving means for moving and rotating the laser three-dimensionally, respectively.
[0029]
Each laser is moved and rotated by the moving means so that the laser irradiation light shown by the dotted line can display three axes of a three-axis cross section arbitrarily defined in a GUI described later. . Incidentally, each laser is normally fixed at a fixed position so as to display three axes serving as references.
[0030]
Next, a method of irradiating a display screen and a predetermined portion in a subject with laser irradiation light using the medical image diagnostic apparatus having the above configuration will be described with reference to FIGS.
[0031]
As shown in FIG. 3, first, a tomographic image of a subject is captured by a medical image diagnostic apparatus (step 101). Subsequently, after image processing using MPR (Multi-Planer Reconstruction), MIP (Maximum Intensity Projection), volume rendering (Volume Rendering), or the like, a three-axis image (for example, a cross-sectional image orthogonal to the body axis of the subject) is displayed on the display 20. An axial image), a coronal image (coronal section image) and a sagittal image (sagittal section image) orthogonal to the axial image are displayed (step 103).
[0032]
FIG. 4 shows an example of a display screen of the display 20 that displays the above-described three-axis image and the like. An axial image is displayed on the display unit 201 of the four divided display units 201 to 204, and the display unit 202 Indicates a coronal image, a sagittal image is displayed on the display unit 203, and a real-time image such as fluoroscopy is displayed on the display unit 204. Dotted lines 206 to 208 that can be freely moved by dragging with a mouse or the like are displayed on the display units 201 to 203. These dotted lines 206 to 208 are used as a tool for selecting an arbitrary cross section.
[0033]
Returning to FIG. 3, the operator (user) operates the tool to select an arbitrary cross section (three axes) (step 104). As the arbitrary cross section, for example, a cross section including a puncture start position by a puncture needle and a desired site (such as a tumor) in a living body is selected.
[0034]
Subsequently, based on the arbitrary cross section (each cross section defined by the GUI) selected by the user, the coordinate position and the triaxial direction of the three-axis orthogonal point (desired part) in the real space are automatically calculated, and the coordinate position is calculated. The information is transmitted to the moving means of the optical display 21 as position information necessary for pointing by laser irradiation light from three axial directions (step 105).
[0035]
The moving means moves the laser 21x for displaying the x direction, the laser 21y for displaying the y direction, and the laser 21z for displaying the z direction of the optical display 21 for displaying the three axes based on the transmitted positional information ( Step 106). Then, when the laser irradiation light is irradiated (by turning on the light display 21) according to the user's intention (ON / OFF function of the light display 21), the laser irradiation light is received as shown by a solid line 205 in FIG. The sample is irradiated (step 107).
[0036]
With the aid of laser irradiation light emitted from each laser, processing / surgery (puncture, incision, etc.) according to the purpose is performed on the subject (step 108). In addition, the laser irradiation light emitted from each laser is such that only the spot light on the subject can be visually observed, and in this embodiment, five spot lights can be visually observed. The puncture start position by the puncture needle is shown. In addition, the puncturing direction can be grasped from the position of the spot light facing the spot light indicating the puncturing start position. Further, the user can predict the position of the intersection (depth to be punctured) where the laser light crosses when the laser light passes through the inside of the subject from the positions of these spot lights. The medical image diagnostic apparatus has a function of capturing / displaying the selected selected cross section (particularly, a cross section including the puncturing start position) in real time. For example, a real time image such as an MRI fluoroscopic image is displayed. No. 4 is displayed on the display unit 204 of the display screen of the display. The shooting sequence in this case is a sequence for fluoroscopy such as a GrE sequence or a multi-shot EPI. In these sequences, the image can be updated every 0.5 to 4 seconds, and monitoring of the puncture needle can be performed using this real-time image.
[0037]
On the other hand, when the display section is to be changed, the process returns to step 104, where a new arbitrary section is selected. When the target site is changed, the process returns to step 101, and the tomographic image including the target site is returned. Imaging is performed, and the above processing is repeated. This function is completed when the target is achieved by the operation support.
[0038]
In the embodiment shown in FIG. 4, an arbitrary cross section can be selected by moving the three reference axes in parallel. However, the present invention is not limited to this. On the display units 301 to 303 of the display 20 shown in FIG. , The solid lines 306 to 308 can be freely rotated, and the inclination of an arbitrary cross section can be selected by the solid lines 306 to 308. By automatically calculating the coordinate position and the three-axis directions of the desired part in the real space based on the arbitrary cross section selected in this manner, the subject is irradiated with laser irradiation light as shown by a solid line 305 in FIG. can do.
[0039]
The optical display is not limited to the one using the He-Ne laser, but may be one using other light emitting means (such as a light emitting diode) that emits light harmless to the human body. In this embodiment, the operator is instructed to select a measurement sequence in advance. However, when continuously acquiring data, the operator can freely change the sequence and settings even during measurement depending on the target site and conditions. It also has a mechanism. In addition, in the above description, the case where two-dimensional measurement data is used as the basic measurement data has been described. However, even with three-dimensional measurement data, any type of data can be obtained in the same manner, and the same effect can be obtained. .
[0040]
In this embodiment, an arbitrary section including a predetermined part is selected using a three-axis image. However, an arbitrary section may be selected using a two-axis image. Further, the medical image diagnostic apparatus according to the present invention is not limited to the MRI apparatus according to this embodiment, but may be an X-ray CT apparatus, an ultrasonic diagnostic apparatus, or the like.
[0041]
【The invention's effect】
As described above, according to the present invention, an access start position, a target position, and a direction at the time of accessing a living body with a treatment instrument such as a puncture needle can be displayed by a light beam in a real space, and an operator can be displayed. I can assist you.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing the overall configuration of a medical image diagnostic apparatus according to the present invention; FIG. 2 is a diagram used to explain the arrangement and configuration of the optical display shown in FIG. 1; FIG. FIG. 4 is a flowchart showing a procedure for displaying a target part during the operation of FIG. 4. FIG. 4 is a view showing an example of a display screen of the display shown in FIG. 1. FIG. 5 is based on an arbitrary cross section selected on the display screen of FIG. FIG. 6 is a view showing another example of a display screen of the display shown in FIG. 1; FIG. 7 is a view showing another example of the display screen of the display shown in FIG. 1 FIG. FIG. 8 is a view showing laser irradiation light whose position and irradiation direction are controlled. FIG. 8 is a flowchart used to explain a conventional method of displaying a target portion during surgery.
DESCRIPTION OF SYMBOLS 1 ... Subject, 2 ... Static magnetic field generation magnet, 3 ... Gradient magnetic field generation system, 4 ... Sequencer, 5 ... Transmission system, 6 ... Reception system, 7 ... Signal processing system, 8 ... CPU, 9 ... Gradient magnetic field coil, 10 ... Gradient magnetic field power supply, 14a ... High-frequency coil on transmission side, 14b ... High-frequency coil on reception side, 16 ... Quadrature detector, 20 ... Display, 21 ... Optical display, 21x ... Laser for x-direction display, 21y ... Y-direction Laser for display, laser for 21z ... z direction display

Claims (1)

In a medical image diagnostic apparatus capable of capturing and displaying a cross-sectional image at an arbitrary cross-section of a subject,
Display means for displaying a plurality of cross-sectional images of the subject taken in at least two of the orthogonal three-axis directions;
Selection means for selecting an arbitrary position indicating the same site using the plurality of cross-sectional images,
Calculating means for calculating a coordinate position of the position in the real space from an arbitrary position selected by the selecting means,
Light display means for irradiating the subject with a plurality of light beams,
Control means for controlling the light display means so that the plurality of light beams indicate the coordinate position based on the calculated coordinate position,
A medical image diagnostic apparatus comprising:

Images