JP2003126061A - Image diagnostic apparatus with microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image diagnostic apparatus with a microscope which shows excellent operability and allows a simultaneous observation of an image by the image diagnostic apparatus and an image by the microscope. SOLUTION: The image diagnostic apparatus is equipped with a magnet 11 generating a static magnetic field, a unit 10 for generating a homogeneous magnetic field which has a gradient magnetic field coil 12 and a RF coil 13 and forms a homogeneous magnetic space necessary for imaging, a driving system 20 to drive each coil, an image processing system 30 which reconstructs an image by using signals detected by the RF coil and displays the image, and a supporting part 50 to support the unit 10 for generating magnetic field movably. The unit 10 is equipped with an optical unit penetrating through the center of the unit 10 and constituting the microscope 40. Since the microscope 40 is equipped with a half mirror 45, leading the image displayed by the image processing system to an ocular lens 44, between an optical system 42 and the ocular lens 44, the image displayed on a displaying part and an image by the microscope can be observed simultaneously.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image diagnostic apparatus for taking an image by utilizing a magnetic resonance phenomenon or electron spin resonance, and in particular, it is equipped with a microscope and observes a microscope image simultaneously with an image acquired by the image diagnostic apparatus. The present invention relates to an image diagnostic device that can

[0002]

2. Description of the Related Art Conventionally, a magnetic resonance imaging apparatus (hereinafter referred to as an MRI apparatus) using a cylindrical magnet capable of generating a relatively uniform and strong magnetic field has been widely used.
The MRI apparatus having such a configuration gives a patient a feeling of blockage and has a problem that access from the outside is extremely difficult. On the other hand, by applying the Helmholtz coil principle, an MRI apparatus in which two separated magnets are arranged facing each other with their central axes aligned and the space in which the patient is placed is open is proposed and put to practical use. Has become.

As such an open type MRI apparatus,
Depending on the arrangement direction of the magnets, there are vertical magnetic fields and horizontal magnetic fields. Among them, the one with a vertical magnetic field is used for simple surgery (interventional procedure, IVMR) such as biopsy using an MRI device as a monitor because it is easily accessible from the outside to the patient. On the other hand, surgery (microsurgery) using a microscope is widely performed in fields such as brain surgery, and there is a demand for the IVMR to be used in combination with a microscope.

However, the above-mentioned open type MRI apparatus has a structure in which a pair of magnets are arranged vertically or horizontally with a measurement space sandwiched, as shown in FIG. There are restrictions on the installation of the microscope.
In particular, in the vertical magnetic field type MRI apparatus as shown in FIG.
It is difficult to set up a space above the measurement space to operate the microscope. Therefore, in order to use the MRI image for the microsurgery, it is necessary to move the patient and perform the operation under the microscope after performing the imaging in the MRI apparatus, or to perform the operation in the reverse order. As a result, the MR image and the stereoscopic image under the microscope are temporally and spatially displaced from each other, which makes it impossible to effectively use the MR image. For the imaging by the MRI apparatus and the movement of the patient between the operating tables. There was a problem that the operation time was prolonged due to the time required.

To solve these problems, MRI
An MRI apparatus has been proposed in which two magnets of the apparatus are movable and one magnet is attached with a microscope (optical means) (Japanese Patent Laid-Open No. 10-43159). In this MRI apparatus, there is no limitation on the approach of the optical means to the patient, and since the imaging region of the MRI apparatus always exists on the optical center line of the optical means, there is an advantage that the surgical fields of the optical means and the MRI always match. is there.

[0006]

However, in this MRI apparatus, in order to position the optical means in an arbitrary direction with respect to the patient, one magnet equipped with the optical means and the other magnet are respectively moved, and Must be positioned so that the axes are aligned. At that time, in order to prevent the two magnets from approaching each other due to the electromagnetic attraction force, each magnet must be fixed by a strong fixing and holding means, and the moving operation cannot always be performed easily.

Further, in the conventional microsurgery using the MRI apparatus, since MR images are displayed on a monitor such as a CRT or a liquid crystal display, the operator separately separates the images displayed on these monitors from the microscopic images. It was necessary to observe, and the operability was not always good.

Therefore, an object of the present invention is to provide an image diagnostic apparatus with a microscope, which reduces a mechanical load on a fixing portion for fixing a magnet and is excellent in operability. It is another object of the present invention to provide an image diagnostic apparatus with a microscope that can obtain a good image of a target area and that can simultaneously observe the image and the microscope image.

[0009]

An image diagnostic apparatus with a microscope of the present invention which achieves the above object has a static magnetic field generating magnet, a gradient magnetic field coil and an RF coil, and forms a uniform magnetic field space necessary for imaging. One magnetic field generation unit, a drive system for driving each of the coils, an image processing system for reconstructing and displaying an image using a signal detected by the RF coil, and a support for movably supporting the magnetic field generation unit. An image diagnostic apparatus including a mechanism, wherein the magnetic field generation unit comprises:
An optical unit that constitutes the microscope is provided so as to penetrate the central portion.

According to this image diagnostic apparatus with a microscope, a single magnetic field generating unit is provided and a microscope is provided therein, so that the mechanical load on the support mechanism of the magnetic field generating unit is reduced and the magnetic field generating unit is integrated. It is possible to easily operate the modified microscope.

The image diagnostic apparatus with a microscope of the present invention is
The microscope is provided with an objective lens, an optical system and an eyepiece lens, and means for introducing an image displayed in the image processing system into the eyepiece lens is provided between the optical system and the eyepiece lens. According to this image diagnostic apparatus with a microscope, a microscope image of the object placed behind the objective lens and an image obtained by photographing the object with the image diagnostic apparatus are simultaneously superimposed through the eyepiece lens. Can be observed. Therefore, in the application of the present image diagnostic apparatus to microsurgery, the operator can proceed with imaging and image observation by the image diagnostic apparatus while continuing surgery.

Further, in the image diagnostic apparatus with a microscope of the present invention, the gradient magnetic field strength for determining the imaging cross section of the subject is set in association with the focal length of the microscope. As a result, it is possible to acquire and display a cross section including a site observed by a microscope in the microsurgery as an image.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which an image diagnostic apparatus with a microscope of the present invention is applied to an MRI apparatus will be described below with reference to the drawings.

FIG. 1 is a diagram showing the overall configuration of the MRI apparatus of this embodiment, and FIG. 2 is a diagram showing the essential parts thereof. As shown in the figure, this MRI apparatus includes a magnetic field generation unit 10 in which a static magnetic field generation magnet 11, a gradient magnetic field coil 12 and an RF coil 13 are integrated, and a gradient magnetic field power source 21 as a drive system 20 for these magnetic field generation units 10, An image processing system 30 that includes a synthesizer 22, a transmission system RF amplifier 23, and a sequencer 24, detects an NMR signal and forms an image, and a reception system RF amplifier 31 and an A / D.
It includes a converter 32, an image processing device 33, an image display device 34, and the like. Furthermore, this MRI apparatus is equipped with a magnetic field generation unit 10
Is provided with a microscope unit 40, which is supported by a support rod with a movable mechanism (not shown). In such a configuration, the magnetic field unit 10 to which the microscope unit 40 is fixed and the image display device 34 are installed in a magnetically shielded shield room / operating room, and other elements are elements in the shield room via cables. Is installed outside the shielded room.

As the static magnetic field generating magnet 11, a general MRI is used.
Although it is possible to use a permanent magnet, a normal conduction type, or a superconducting type static magnetic field generating magnet 11 used in the device,
A normal conducting static magnetic field generating magnet that is lightweight, has excellent operability, and can achieve high magnetic field homogeneity in a relatively narrow region is suitable. In the present embodiment, the gradient magnetic field coil 12 and the RF
A solenoid coil that generates a magnetic field parallel to the stacking direction with the coil 13 is adopted. Although not shown in FIG. 1, when a normal conducting coil is used, its driving power source is provided.

The gradient magnetic field coil 12 generates gradient magnetic fields Gx, Gy, Gz in the directions of three axes orthogonal to each other.
It is composed of two coils and is connected to the gradient magnetic field power source 21, respectively. Each of the three coils is formed in a flat plate shape,
They are insulated, laminated and integrated with each other. The imaging cross section of the subject can be arbitrarily selected by applying these gradient magnetic fields. In the MRI apparatus of this embodiment, the gradient magnetic field for selecting the cross section (slice) is set in association with the focal length of the microscope. This will be described later.

The RF coil 13 is a transmission / reception RF coil for irradiating the subject with an RF pulse which is an electromagnetic wave having a resonance frequency and for receiving an NMR signal emitted by the subject by nuclear magnetic resonance. The RF coil 13 from the synthesizer 22 is used as the RF coil. It is connected to a transmission system RF amplifier 23 that amplifies the pulse, and is also connected to a reception system RF amplifier 31 that amplifies the NMR signal received by the RF coil 13.

These static magnetic field generating magnet 11 and gradient magnetic field coil
The 12 and the RF coil 13 are mechanically integrated by stacking them in this order so that the gradient magnetic field coil 12 and the RF coil 13 are housed in the static magnetic field space generated by the static magnetic field generating magnet 11, and the center thereof is provided. The microscope 40 is fixed through the portion. The configuration of these magnetic field generation units 10 will be described later.

The drive system 20 drives the gradient magnetic field power source 21 and the synthesizer 22 in accordance with a command from the sequencer 24, and applies a predetermined gradient magnetic field and RF pulse to the subject through the gradient magnetic field coil 12 and the RF coil 13. To do. The timing of magnetic field application controlled by the sequencer 24 is called a pulse sequence, and various pulse sequences determined by the imaging method are pre-installed in the image processing device 33 as a program. The sequencer 24 is driven by a command from the image processing device 33.

The image processing system 30 amplifies the NMR signal received by the RF coil 13 by the RF amplifier 31, and then the A / D converter 3
In step 2, it is converted into a digital signal and sent to the image processing device 33. The image processing device 33 performs various calculations such as correction coefficient and image reconstruction on the digital signal, and causes the image display device 34 to display a calculation result such as an image showing a cross section of the subject. The image processing device 33 includes a keyboard for inputting imaging conditions,
An input device 35 such as a mouse, a monitor 36 for displaying a user interface image at the time of input and a calculation result, an external storage device (not shown), and the like are provided.

Next, the details of the magnetic field generating unit will be described with reference to FIG. As shown, the static magnetic field generating magnet 11 is
It is composed of a static magnetic field generating coil 11a and a magnetic correction ring 11b.
The magnetic correction ring 11b is a member for correcting the static magnetic field generated by the static magnetic field generating coil 11a in the vertical direction (arrow direction) in the figure to improve the homogeneity, and is made of a ferromagnetic material such as iron, It has a shape in which an outer peripheral ring protruding in a direction perpendicular to the disc surface is formed on the outer periphery. Microscope in the center of the disc
A hole through which 40 passes is provided. Static magnetic field generating coil 11
For example, a is provided outside the outer peripheral ring of the magnetic correction ring 11b or along the outer periphery of the disk.

The static magnetic field generating magnet 11 having such a structure prevents the magnetic flux formed by the static magnetic field generating coil 11a from spreading to the outside of the coil, and provides a uniform static magnetic field on the side where the outer peripheral ring is formed. Can occur. Specifically, when the diameter of the static magnetic field generating coil 11a is set to several tens of cm,
A uniform magnetic field that provides a field of view FOV of 5 to 10 cm can be formed below the magnetic field generation unit 10. M of the present invention
Since the RI apparatus images the magnetic field generation unit 10 in close proximity to the imaging site of the subject, a uniform static magnetic field region is formed in such a range, and thus a practical high-quality MR image is obtained. Can be obtained. Although only one static magnetic field generating coil 11a is shown in the drawing, a plurality of static magnetic field generating coils 11a including a shim coil can be provided, which can further improve the uniformity of the magnetic field and the image quality. Is.

The gradient magnetic field coil 12 and the RF coil 13 are arranged in the space inside the outer peripheral ring of the static magnetic field generating magnet 11 so that their central axes coincide with each other, and are fixed by fixing means (not shown). Also in the gradient magnetic field coil 12 and the RF coil 13,
A hole through which the microscope 40 penetrates is provided in the center.

The microscope 40 is provided with an objective lens 41, an optical system 42, a prism 43, and an eyepiece lens 44, as in a microscope generally used for medical purposes. Further, in the present invention, between the prism 43 and the eyepiece lens 44. A half mirror 45 is inserted in. The objective lens 41 and the optical system 42 are fixed in a hole penetrating the central portion of the magnetic field generation unit 10 so that their optical axes coincide with each other. The prism 43 is an optical path changing unit that guides the light beam from the objective lens 41 to the eyepiece lens 44.

The half mirror 45 is installed on the optical path between the prism 43 and the eyepiece lens 44 at an angle of 45 degrees with respect to the optical path, and guides the light incident perpendicularly to the optical path to the eyepiece lens 44 side. . In the vicinity of the half mirror 45, as shown in FIG.
The display surface of the image display device 34 is installed in a direction orthogonal to the optical path of the microscope. As a result, the MR image displayed on the image display device 34 and the light from the objective lens 41, that is, the microscope image of the surgical site of the patient can be simultaneously observed through the eyepiece lens 44.

The focal length of the microscope 40 is the objective lens 41.
It can be adjusted by adjusting the positional relationship between the optical system 42 and the optical system 42, and the focal length and the slice position to be imaged match. For example, when the slice plane is a plane orthogonal to the optical axis of the microscope, the gradient magnetic field strength that selects the slice plane including the imaging center is set as the default, and the slice position becomes the focal length. Set the position. When the focal length changes due to the adjustment of the focal position, the gradient magnetic field G
Also change the intensity of z.

The intensity of the gradient magnetic field can be changed by obtaining the amount of movement of the focal length from the mechanism for adjusting the focal length and inputting this amount of movement to the image processing device 33 which drives the gradient magnetic field power supply. The change of the gradient magnetic field strength may be completely linked with the focal length, but may be stepwise. For example, when the focal length moves within the slice thickness range, the slice gradient magnetic field is not changed, and when there is a focal length shift that exceeds the slice thickness, the slice gradient magnetic field is changed. Good. This makes it possible to display a cross section including a portion observed with a microscope as an MR image. The gradient magnetic field that determines the slice plane can be arbitrarily set through the input device 35 of the image processing device 33, in addition to the change associated with the focal length.

Next, an M with a microscope having such a configuration is provided.
A specific example of the operating table for microsurgery using the RI apparatus will be described with reference to FIGS. 3 and 4.

As shown in FIG. 3, a support rod 50 for supporting the magnetic field generating unit 10 to which the microscope 40 is fixed is installed near the operating table 60 installed in the operating room (shield room). There is. The support rod 50 is a fixed portion 51 fixed to the floor.
And a movable support arm 52 connected to the fixed portion 51 by a universal joint or the like, and the magnetic field generation unit 10 is fixed to the tip of the support arm 52 via the universal joint or the like. Although not shown, a mechanism for slicing the magnetic field generation unit 10 in the longitudinal direction of the support arm 52 may be provided. A cable connecting each coil constituting the magnetic field generation unit 10 to a drive system and an image processing system and a video cable connecting the image display device 34 to the image processing device 33 are housed in a space inside the support rod 50.

In order to advance the microsurgery in such a configuration, first, the surgical site is incised with the patient lying on the operating table, and if the relevant site is exposed, the magnetic field generating unit with microscope 10 is used. Moving to the upper part, the objective lens 41 of the microscope 40 is brought closer to bring the object into focus. At this time, the slice plane is determined in association with the adjustment of the optical system for focusing, and the MR image including the focus position can be acquired. In this state, the surgery is advanced while observing the microscope image, and MR imaging is performed if necessary. The imaging method is not particularly limited, but it is preferable to adopt a high-speed imaging method such as an EPI method or a high-speed spin echo method in order to enhance the real-time property of the displayed image.

The MR image thus captured is displayed on the image display device 34 in real time and can be viewed through the eyepiece lens 44 from the half mirror 45 of the microscope 40.
An example of the displayed image is shown in FIG. Fig. 5 (a) shows the MR image of a slice plane perpendicular to the optical axis of the microscope 40.
This is an example in which a microscopic image can be observed by superimposing it on the image A. Further, FIG. 5B shows the area around the field of view of the microscope image B or FIG.
This is an example in which another cross-sectional image C including an observation site (focal length), an image D different in slice depth direction, and the like are displayed around the same MR image A as in (a). As described above, it is possible to capture and display an arbitrary MR image that assists surgery depending on the method of displaying the MR image.

In this way, the operator can proceed with the operation by keeping reference to the MR image and keeping the surgical procedure by the microsurgery, without taking his eyes off the surgical site.
Further, since the center of imaging coincides with the focal point of the microscope 40, it is possible to obtain an MR image of the site that is the target of surgery.

Further, in the MRI apparatus with a microscope of the present embodiment, the static magnetic field generating means for forming a uniform magnetic field for imaging is housed in a single magnetic field generating unit, so that the supporting rod 50 serves as the magnetic field generating unit 10. Any mechanism can be used so long as it can withstand the weight, and the operation of the magnetic field generation unit 10 by the support arm 51 can be easily performed.

The embodiment of the present invention has been described above.
The present invention is not limited to the above embodiment, and various modifications can be made. For example, the image display device 34 may be provided at a fixed position with respect to the half mirror 45 of the microscope 40, but in order to enable observation of only the MR image separately from superimposition observation of the MR image and the microscope image. The display surface of the image display device 34 may be movable.

Further, in the present invention, the MRI apparatus having a structure capable of superposing and observing an MR image and a microscopic image is provided with a magnetic field generating unit 10 for independently forming a uniform magnetic field space necessary for photographing as a static magnetic field generating means. It is also possible to apply not only to the above, but also to an MRI apparatus configured to form a magnetic field space by combining with other static magnetic field generating means.

Further, in the above-mentioned embodiment, the MRI apparatus has been described as an image diagnostic apparatus, but the present invention can be similarly applied to an apparatus (ESR apparatus) for imaging a subject by utilizing electron spin resonance. The ESR apparatus may have a lower static magnetic field strength than the MRI apparatus, and thus can be easily realized. Also E
Since SR is excellent in depicting the surface state, it is possible to select MRI or ESR according to the purpose of microsurgery.

[0037]

According to the present invention, by incorporating a microscope into a single magnetic field generating unit, which is a magnetic field generating means of an image diagnostic apparatus, and making the microscope movable, the mechanical load on the movable portion can be minimized. It is possible to provide an image diagnostic apparatus with a microscope, which has excellent operability and is suitable for microsurgery. Further, according to the present invention, by providing a means for introducing light from the image display unit of the image diagnostic apparatus on the optical path of the microscope of the image diagnostic apparatus with a microscope, the image by the image diagnostic apparatus and the microscope image are superimposed or It can be observed in parallel at the same time. As a result, microsurgery that effectively uses the information of the image diagnostic apparatus becomes possible without extending the operation time.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of an MRI apparatus with a microscope of the present invention.

FIG. 2 is a diagram showing a main part of an embodiment of an MRI apparatus with a microscope of the present invention.

FIG. 3 is a view showing an installation state of an MRI apparatus with a microscope of the present invention in an operating room.

FIG. 4 is a diagram illustrating a microsurgery using the MRI apparatus with a microscope of the present invention.

FIG. 5 is a view exemplifying an image observed in the MRI apparatus with a microscope of the present invention.

FIG. 6 is a diagram showing a structure of a static magnetic field magnet of a conventional MRI apparatus.

[Explanation of symbols]

10 ... Magnetic field generation unit 11-Static magnetic field generating magnet 12: Gradient magnetic field coil 13 ... RF coil 20 ... Drive system 30: Image processing system 34. Image display device 40 ... Microscope 41 ... Objective lens 42 ... Optical system 44 ・ ・ ・ Eyepiece 45 ... Half mirror 50 ... Support rod

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H052 AB26 AD04 AD06 AF01 AF14                       AF22                 4C096 AA18 AA20 AB41 AB50 AC01                       AD19 AD23 BA41 BA42 CA05                       CA16 CA23 CA33 CA43 DB13                       DB20 DC18 DD20 FC20

Claims (4)

[Claims] 1. A static magnetic field generating magnet, a gradient magnetic field coil and R
A single magnetic field generation unit that has an F coil and forms a uniform magnetic field space necessary for imaging, a drive system that drives each of the coils, and an image is reconstructed and displayed using signals detected by the RF coil. An image diagnostic system including an image processing system that supports the magnetic field generating unit and a supporting unit that movably supports the magnetic field generating unit. An image diagnostic apparatus with a microscope, which is provided. 2. The microscope includes an objective lens, an optical system, and an eyepiece lens, and between the optical system and the eyepiece lens,
The image diagnostic apparatus with a microscope according to claim 1, further comprising means for introducing an image displayed in the image processing system into an eyepiece lens. 3. A static magnetic field generating magnet, a gradient magnetic field coil and R
A magnetic field generation unit having an F coil, a drive system for driving each coil, an image processing system for reconstructing and displaying an image using a signal detected by the RF coil, and a movable magnetic field generation unit. An image diagnostic apparatus having a supporting unit for supporting, wherein the magnetic field generation unit penetrates through a central portion thereof and is provided with an optical unit that constitutes a microscope, and the microscope is displayed in the image processing system. An image diagnostic apparatus with a microscope having means for introducing an image into an eyepiece. 4. The microscope according to claim 1, wherein the gradient magnetic field strength for determining the imaging cross section of the subject is set in association with the focal length of the microscope. Image diagnostic equipment.