JP2003190117A - Medical operation support system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a medical operation support system in which the current state of a desired cross section can be imaged while performing the navigation of a medical operation using volume data imaged in the past. <P>SOLUTION: A processor 2 displays the tomograph of three cross sections including the coordinates of the distal end of a pointer 6 by using the volume data imaged by an MRI system 1 in the past. Besides, when a scan is instructed from an operator, a main control part 26 calculates a scan cross section from the coordinates of the distal end of the pointer 6 or from an instructed direction and requests imaging of the scan cross section to the MRI system 1. Corresponding to this request, a CPU 208 of the MRI system 2 controls imaging of the tomograph of the designated scan cross section. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a surgery support system using a magnetic resonance imaging apparatus.

[0002]

2. Description of the Related Art A magnetic resonance imaging apparatus (hereinafter referred to as "MR
"I device" is used to measure the density distribution of the nuclear spins and the time distribution of the nuclear spins at the desired inspection site in the subject using the nuclear magnetic resonance (NMR) phenomenon, and the measured data is used to determine the subject. This is an image display of an arbitrary cross section of.

As one of the applications of such an MRI apparatus,
Surgical navigation systems are known.

The surgical navigation system displays a position designated by a pointer or the like for a patient during a surgical operation on a tomographic image of the patient including the position and having three orthogonal planes as cross sections. This system is applied to high precision surgical operations such as neurosurgery.

Here, a tomographic image of a patient in such a surgical navigation system is generated in advance from volume data which is three-dimensional data imaged by an MRI apparatus. On the other hand, there are methods such as a mechanical method, an optical method, a magnetic method, and an ultrasonic method as a method of detecting the position of the pointer that is necessary to determine the designated position by the pointer.

Correspondence (registration) between the detected position of the pointer and the position in the volume data is performed by, for example, fixing a plurality of patient markers to the patient and imaging the patient marker in the volume. It is performed by imprinting it, and associating the detected position of the pointer at the time when the patient marker is pointed with the pointer with the patient marker position in the three-dimensional data. For information on such surgical navigation technology, see “Surgery Navigation in Neurosurgery: Surgery Vol.54 (12) P1674-168.
Detailed in 0, 2000 ”etc.

On the other hand, as another application of the MRI apparatus, a real-time moving body imaging method called fluoroscopy (fluoroscopic imaging) is known.

The fluoroscopy is a technique for displaying images as if they were fluoroscopic images of X-rays by repeating short-time imaging of about 1 second or less and image reconstruction. Where MRI
In the fluoroscopy in the apparatus, since it takes a long time to acquire all volume data, only one cross section is set as an imaging plane to ensure time resolution, and imaging and image reconstruction are repeated for only one imaging plane. Is being done.

As a technique for operating the imaging surface in such a fluoroscopy, a three-direction camera and an LED attached to a puncture needle are used to detect the approach direction of the needle and automatically detect the position and direction of the device, A technique called interactive scanning is known in which the imaging surface is operated according to the detected position and direction.

A technique known as partial phase encoding (partial encoding) that partially diverts past measurement data is known as a technique for ensuring good time resolution in fluoroscopy without significantly degrading image quality. ing. For example, Keyhole measurement, which is a typical method of partial encoding, uses the characteristic that the data in the central part of k-space predominantly determines the contrast, and measures only the data in the central part of k-space. , The time resolution is improved without significantly degrading the image quality. However, when the target moves, it is common to measure data outside the k space (spatial high frequency information) at a constant cycle.

Regarding the Keyho1e measurement, "Composite K-space windows (Keyhole Techniques)" by Brummer et al.
to improve temporal resolution in dynamic series
of image following contrast administration: SMRM P
roc., P4236, 1996 ", and other partial encoding measurements are also described in Mist11etta et al. (US Pat. No. 571335).
8 and 5830l43).

As a technique for high-speed imaging in the conventional magnetic resonance imaging apparatus, in addition to the spin echo method and the gradient echo method, which are basic imaging sequences, an echo planar (Echo Planar Imaging) method and a high-speed spin echo ( Techniques such as Fast Spin Echo) have been devised that enable faster image transfer.

The fast spin echo method applies a multi-echo method in which transverse magnetization generated by 90 ° pulse excitation is repeatedly inverted by RF to generate multiple echoes, and different phase encoding is applied to each echo signal. By dividing the RARE method, which can obtain l images at high speed, into a plurality of sequence sequences, an image quality similar to that of the spin echo method can be obtained.

On the other hand, in the echo planar method, the gradient magnetic field for reading is inverted at high speed without using the inversion by RF.
It is a method of acquiring multiple echoes with one excitation pulse,
Ultra-high speed imaging of tens of ms is possible, but it is extremely sensitive to static magnetic field inhomogeneity.

[0015]

Since the above-mentioned floroscopy technique reflects the condition in real time, if it is applied to the puncture guide as interventional MRI, it is effective in minimizing the invasion. However, since it is necessary to perform imaging in a short time to ensure real-time processing, even if the above-mentioned various techniques for speeding up imaging are applied, sufficient spatial resolution and S / N are still provided. It is difficult to obtain high quality images. Therefore, it may be difficult to perform a precise puncture guide or the like with this technique.

On the other hand, according to the above-mentioned surgical navigation technique, the volume data to be used is captured in the past, and the length of time required for this capturing does not matter so much. Although the navigation of the surgical operation such as the guide can be performed, the current state of the subject cannot be presented to the operator.

Therefore, it is an object of the present invention to provide a surgery support system capable of measuring the current state while performing surgery navigation using high-quality images.

[0018]

[Means for Solving the Problems] To achieve the above objects,
The present invention provides a surgical operation support system using a magnetic resonance imaging apparatus that measures tomographic data of a subject and volume data, which is a set of tomographic data, using a nuclear magnetic resonance phenomenon, and indicates a processing apparatus and an operation target. A volume data storage unit for storing the volume data of the object measured by the magnetic resonance imaging apparatus, a position detection unit for detecting the position of the indicator, and The position on the volume data space stored in the volume data storage unit that corresponds to the position detected by the position detection unit is the position on the tomographic image or the three-dimensional representation image generated from the volume data stored in the volume data storage unit. And the navigation means displayed as, and the scan according to the position detected by the position detection means. Set down section, provided a scanning means for requesting the measurement of scanning cross section is set to the magnetic resonance imaging apparatus, said magnetic resonance imaging apparatus,
The tomographic data of the requested scan section is measured.

Further, in such a surgery support system, the magnetic resonance imaging apparatus transfers the measured tomographic data of the scan section to the processing apparatus, and the scanning means of the processing apparatus transfers. The tomographic image of the scan section is displayed based on the tomographic data.

According to such a surgical operation support system, in parallel with the surgical navigation by the high quality image using the volume data photographed in the past, the setting of the scanning cross section, the measurement of the scanning cross section or the measurement and imaging is performed.
It is performed according to the operation of the pointer of the operator used in surgical navigation. Therefore, it is possible to perform surgical navigation using a high-quality image and to provide the operator with a tomographic image showing the current state of the desired cross section of the subject without imposing an extra burden.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

FIG. 1 shows the configuration of the surgery support system according to this embodiment. As shown in the figure, the present surgery support system includes an MRI device 1, a processing device 2, a display device 3, a position detection device 4, an input device 5, a pointer 6, and a patient marker fixed to a patient. 7 and a device marker 8 fixed to the MRI apparatus 1.

Further, the processing device 2 includes a volume data storage unit 21, a position detection processing unit 22, a tomographic image generation unit 23,
A volume rendering processing unit 24, a display processing unit 25,
It has a main control unit 26, a scan image storage unit 27, and a scan image generation unit 28.

Next, the structure of the MRI apparatus 1 is shown in FIG. As shown in the figure, the MRI apparatus obtains a tomographic image of a subject by utilizing a nuclear magnetic resonance (NMR) phenomenon, and includes a static magnetic field generating magnet 202, a gradient magnetic field generating system 203, a transmitting system 205,
Reception system 206, signal processing system 207, sequencer 20
4 and a central processing unit (CPU) 208.

The static magnetic field generating magnet 202 is used for the subject 20.
A uniform static magnetic field is generated around 1 in the body axis direction or in a direction orthogonal to the body axis, and a permanent magnet system, normal conduction system, or superconductivity system is provided in a space with a certain extent around the subject 201. The magnetic field generating means is arranged. The static magnetic field generating magnet 202 has an open structure with a wide frontage so that the subject 201 can be easily accessed.

The gradient magnetic field generating system 203 is composed of a gradient magnetic field coil 209 wound in three axial directions of X, Y and Z, and a gradient magnetic field power source 210 for driving each of the gradient magnetic field coils. The gradient magnetic field power source 210 of each coil is driven according to the command of X, Y,
Gradient magnetic fields Gx, Gy, and Gz in the triaxial directions of Z are applied to the subject 201. Here, the slice plane for the subject 201 can be arbitrarily set by the method of applying the gradient magnetic field.

The sequencer 204 performs control to repeatedly apply a high frequency magnetic field pulse that causes nuclear magnetic resonance to the atomic nuclei of the atoms constituting the biological tissue of the subject 201 in a predetermined pulse sequence. And sends various commands necessary for collecting data on the tomographic plane of the subject 201 to the transmission system 205 and the gradient magnetic field generation system 20.
3 and the reception system 206.

The transmission system 205 irradiates a high frequency magnetic field in order to cause nuclear magnetic resonance in the atomic nuclei of the atoms constituting the biological tissue of the subject 201 by the high frequency pulse sent from the sequencer 204.
1, a modulator 212, a high frequency amplifier 213 and a high frequency coil 214a on the transmission side. The high frequency pulse output from the high frequency oscillator 211 is output to the sequencer 20.
4 is amplitude-modulated by the modulator 212, the amplitude-modulated high-frequency pulse is amplified by the high-frequency amplifier 213, and then supplied to the high-frequency coil 214a arranged in the vicinity of the subject 201, thereby Is irradiated on the subject 201.

The receiving system 206 receives the echo signal (NM) emitted by the nuclear magnetic resonance of the atomic nuclei of the biological tissue of the subject 201.
R signal) is detected, and the high frequency coil 21 on the receiving side
4b, an amplifier 215, a quadrature detector 216, and an A / D converter 217. Then, the object 201 to be inspected by the electromagnetic wave emitted from the high-frequency coil 214a on the transmitting side.
The response electromagnetic wave (NMR signal) is detected by the high-frequency coil 214b arranged close to the subject 201, and the A / D converter 2 is passed through the amplifier 215 and the quadrature detector 216.
It is input to 17 and converted into a digital amount. Further, this digital amount is sent to the signal processing system 207 as two series of collected data sampled by the quadrature phase detector 216 at the timing according to the instruction from the sequencer 204.

The signal processing system 207 comprises a CPU 208, a recording device such as a magnetic disk 218 and a magneto-optical disk 219, and a display 220 such as a CRT.
At 08, processing such as Fourier transform and correction is performed to generate two-dimensional tomographic data and volume data that is a sequence of two-dimensional tomographic data, and using these, a tomographic image of an arbitrary cross section is appropriately displayed on the display 220. It is supposed to be displayed. In addition, the CPU 208 transfers the volume data and the tomographic image of the designated cross-section as described above to the processing device 2 in response to a request from the processing device 2, and transfers the captured tomographic data and volume data to the processing device 2. Perform processing to In FIG. 2, the high frequency coil 2 on the transmitting side and the receiving side
14a and 214b and the gradient magnetic field coil 209
1 is installed in the magnetic field space of the static magnetic field generating magnet 202 arranged in the space around 1.

The operation of such a surgery support system will be described below.

First, prior to surgery, a plurality of patient markers 7
The MRI apparatus 1 acquires the volume data of the patient whose position is fixed. The volume data acquired by the MRI apparatus 1 is transferred to the processing device 2 and stored in the volume data storage unit 21.

Next, when the operation is started, the main control unit 26 of the processing device 2 performs the following registration operation.

That is, when the operator instructs each patient marker 7 with the tip of the pointer 6 and gives an instruction for registration from the input device 5, the position detection processing section 22 which receives this instruction via the main control section 26. First, the relative coordinates of the tip of the pointer 6 with respect to the MRI apparatus 1 in the real space are calculated based on the apparatus marker 8.

Here, as a method of detecting the coordinates of the tip of the pointer 6, there are known methods such as a mechanical method, an optical method, a magnetic method, and an ultrasonic method. In the mechanical type, the pointer 6 is attached to the tip of an articulated arm, and the position of the tip of the pointer 6 is calculated from the angle of each arm. On the other hand, in the optical method, a marker (for example, a light source such as a light emitting diode) is provided on the pointer 6, and the position of the tip of the pointer 6 is detected from the position of each marker calculated from the images taken by a plurality of cameras having parallax. The reflected infrared light is photographed by a plurality of cameras having parallax, and the position of the tip of the pointer 6 is detected from the photographed image. The magnetic method creates an orthogonal magnetic field gradient, detects changes in the magnetic field strength in each direction, and detects the position of the tip of the pointer 6 from this. In the ultrasonic method, a sound source is provided on the pointer 6 and the sound from the sound source arrives at the microphone at three locations.
The position of the tip of the.

In the present embodiment, as an example, a case where the tip position of the pointer 6 is detected by an optical method will be described. The position detection device 4 includes a plurality of cameras 41 provided at intervals (with parallax), and a plurality of markers 61 are fixed to the pointer 6. Further, the device marker 8 fixed to the MRI apparatus 1 is also provided with a plurality of markers 81 such as a light source such as a light emitting diode and a reflecting sphere.

First, the position detection processing unit 22 initializes the position detection device 4 of each marker 81 from the displacement of the position of the marker 81 of the device marker 8 in each image taken by each camera of the position detection device 4. The coordinates on the defined detection space are obtained. Then, based on the coordinates of each marker 81, the definition of the detection space is corrected so as to match the measurement space defined in the MRI apparatus 1. That is, the coordinates in the detection space detected by the position detection processing unit 22 corresponding to the coordinates in the same real space are made to coincide with the coordinates in the measurement space used by the MRI apparatus 1.

The position detection processing section 22 calculates the coordinates in the detection space of each marker 61 and the coordinates of the tip of the pointer 6 from the displacement of the position of the marker 61 in each image taken by each camera of the position detection device 4. . Further, in the present embodiment, the position detection processing unit 22 also calculates the pointing direction of the pointer 6, that is, the direction of the pointer 6, from the coordinates of the markers 61 on the detection space.

Next, the position detection processing unit 22 calculates the volume data storage unit 2 from the coordinates of the detection space of the tip of the pointer 6 calculated for the state in which each patient marker 7 is being designated.
1. The relational expression between each coordinate of the volume data stored in 1 and the coordinate in the detection space, that is, the position of a certain part of the current patient in the detection space and the position where the part of the patient is imaged in the volume data. A relational expression for associating with is obtained and stored as a registration result. More specifically, for example, the calculated coordinates of the detection space of the tip of the pointer 6 are converted into the coordinates in the volume data of the patient marker 7 which is pointed by the tip of the pointer 6 at that time, or A coordinate conversion formula for performing the reverse conversion is obtained and stored as a registration result.

When the registration is completed as described above, the main control unit 26 of the processing device 2 then controls each unit and performs the following navigation operation.

That is, the position detection processing unit 22 detects the position of the tip of the pointer 6 and the pointing direction of the pointer 6, and determines the position of the leading end of the pointer 6 and the pointing direction of the pointer 6, for example, the leading end position of the pointer 6 or the pointer. A space where volume data exists is obtained as a designated position by advancing a predetermined distance in the designated direction of the pointer 6 from the tip position of 6, and the obtained designated position and the designated direction of the pointer 6 are calculated according to the relational expression of the previously obtained registration result. It is converted into an upper position (hereinafter referred to as “processing position”) and a direction (hereinafter referred to as “processing direction”).

The tomographic image generating unit 23 generates a tomographic image of a tomographic image including a processing position from each of the three orthogonal planes from the volume data stored in the volume data storage unit 21. In addition, at this time, a cross cursor indicating the processing position is included in each tomographic image.

A volume rendering image is also generated if necessary. In this case, the volume rendering processing unit 24 sets the processing direction as the line-of-sight direction with respect to the volume data stored in the volume data storage unit 21, and views a point at a predetermined distance from the center of the volume data in the direction opposite to the line-of-sight direction. Volume rendering is performed to generate a volume rendering image. At this time, the volume rendering image includes three planes that are orthogonal to each other as described above, that is, three cross sections of each tomographic image.
Include the display of planes. However, the position of the viewpoint may be a position that is determined with respect to the processing position on the line of sight line passing through the processing position, or a position that is determined with respect to the center of the volume data on the line of sight line direction that passes through the processing position. That is, the position of the viewpoint may be, for example, the processing position itself, a point that is a predetermined distance away from the processing position in the opposite direction to the line-of-sight direction of the line-of-sight direction that passes through the processing position, or the line-of-sight through the processing position. The point may be a predetermined distance away from the center of the volume data in the direction opposite to the line-of-sight direction on the direction line.

Next, the display processing unit 25 displays on the display device 3 the three tomographic images generated by the tomographic image generating unit 23 in each of the three orthogonal directions and the volume rendering image generated by the volume rendering processing unit 24. .

FIG. 3 shows a display example by the display processing unit 25. In the figure, a, b, and c are tomographic images, and the cross cursor in each tomographic image indicates the processing position. Also, d
Is a volume rendering image, and three planes in the figure represent cross sections of three tomographic images.

In addition to the operation of the surgical navigation as described above, the processing device 2 also performs the following operation as required.

That is, when there is a scanning instruction from the operator via the input device 5, the main control unit 26 receives the coordinates of the tip of the pointer 6 in the detection space detected by the position detection processing unit 22 at that time. The scan cross section (cross section to be imaged by the MRI apparatus) is calculated from the or direction.

Here, as the scan section, for example,
1) A plane perpendicular to the pointer pointing direction and the pointer tip, 2) A plane including the pointer tip parallel to the pointer pointing direction, 3) A plane crossing the pointer pointing direction and the pointer tip at a predetermined angle, 4) or more Instead of the pointer tip on the plane, a plane using a position slightly ahead of the pointer tip in the pointer pointing direction can be set. Such setting is performed via the input device 5.
The input device 5 can be integrated with the pointer 6.

When the scan section is set in this way,
The main control unit 26 requests the MRI apparatus 1 to image the determined scan section. The CPU 208 of the MRI apparatus 1 controls the imaging of the scan cross section designated according to this request by an imaging method capable of high-quality tomographic imaging similar to the imaging of volume data, and the tomography obtained as a result of the imaging. The data is transferred to the processing device 2. In the processing device 2, the transferred tomographic data is stored in the scan image storage unit 27.

The scan image generation unit 28 generates a tomographic image of the scan cross section from the tomographic data stored in the scan image storage unit 27, and displays it on the display device 3 via the display processing unit 25.

FIG. 4 shows a display example by the display processing section 25. In the figure, a, b, c and d have the same display as in FIG. 3, and e
Is a tomographic image of the scan section, and the cross cursor in the tomographic image of the scan section is the scan section and the pointer 6.
The intersection of the indicated directions of is shown.

Since the surgery support system of this embodiment has the navigation function and the occasional scanning function, a minimally invasive surgery can be realized by combining them. For example, first, a surgical site is searched while an image acquired in advance with high spatial resolution is displayed by the navigation function, and if an image including the surgical site can be specified, the scan function is used to sequentially set desired scan sections. Images can be captured and displayed, and an image that reflects the momentary changes due to surgery can be acquired.

However, the combination of the scan function and the navigation function is not limited to the above example, and the scan section may be set, imaged, and displayed at any time according to the instruction of the operator, or automatically at regular intervals. The setting of the scan section, the image pickup, and the update of the display may be performed.

In the above description, the tomographic data of the imaged scan section is stored in the scan image storage unit 27. However, instead of or together with this, the volume data stored in the volume data storage unit 21 is stored. The tomographic data corresponding to the scan section may be updated with the tomographic data of the imaged scan section. Also,
It is also possible to combine the imaged tomographic data of the scan section with the same tomographic data of the volume data stored in advance, or to reconstruct the image of the scan section by adding a part of the same tomographic data.

Further, in the above description, the imaging of the scan cross section is performed by the imaging method capable of high-quality tomographic imaging similar to the imaging of volume data, but high-speed imaging different from imaging of volume data is possible. You may carry out by a method etc.

As described above, according to the present embodiment, it is possible to perform the setting of the scan section, the measurement of the scan section, the imaging, etc. in accordance with the operation of the pointer by the operator in parallel with the surgical navigation. Therefore, for example, by inserting the surgical instrument to the target site using navigation with high-quality images based on the volume data captured in the past, and setting the scan section as it is to perform imaging, the current state of the target site is obtained. You will be able to get an accurate grasp of Further, according to the present embodiment, since surgical navigation is performed using previously captured volume data, it is necessary to have high time resolution and high real-time capability for imaging and imaging a scan section in a specific application. It is possible to reduce the number of images, and thereby, it is possible to perform imaging and imaging by the imaging method capable of forming a high-quality image of a scan section.

[0057]

As described above, according to the present invention, it is possible to provide a surgical operation support system capable of measuring the current state while performing surgical navigation with high quality images.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a surgery support system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of an MRI apparatus according to an embodiment of the present invention.

FIG. 3 is a diagram showing an example of a display performed by the surgery support system according to the embodiment of the present invention.

FIG. 4 is a diagram showing an example of a display performed by the surgery support system according to the embodiment of the present invention.

[Explanation of symbols]

1: MRI device, 2: processing device, 3: display device, 4: position detection device, 5: input device, 6: pointer, 7: patient marker, 8: device marker, 21: volume data storage unit,
22: position detection processing unit, 23: tomographic image generation unit, 24:
Volume rendering processing unit, 25: Display processing unit, 2
6: main control unit, 27: scan image storage unit, 28: scan image generation unit

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Miki Tachibana             1-chome 1-14-1 Kanda, Chiyoda-ku, Tokyo             Inside the Hitachi Medical Co. (72) Inventor Hiroshi Iseki             3-7-33 Nishi-nippori, Arakawa-ku, Tokyo Suwa             1st floor F term (reference) 4C096 AA12 AA18 AB41 AD06 AD07                       AD14 AD15 AD22 BA18 BB21                       DC32 DD13

Claims (3)

[Claims] 1. A magnetic resonance imaging apparatus for measuring tomographic data of a subject and volume data, which is a set of tomographic data, by utilizing a nuclear magnetic resonance phenomenon, a processing unit, and an indicator for pointing a surgical target. The processing device includes a volume data storage unit that stores the volume data of the subject measured by the magnetic resonance imaging apparatus, a position detection unit that detects the position of the indicator, and the position detection unit detects the position data. Navigation means for displaying a position in space defined by the volume data stored in the volume data storage means corresponding to the selected position as a position on a tomographic image or a three-dimensional representation image generated from the volume data; Set the scan cross section according to the position detected by the position detection means, and measure the set scan cross section. And a scanning means for requesting to the magnetic resonance imaging apparatus, the magnetic resonance imaging apparatus, the operation support system, characterized by measuring the tomographic data of the requested scanning cross section. 2. The surgery support system according to claim 1, wherein the magnetic resonance imaging apparatus transfers the measured tomographic data of the scan section to the processing apparatus, and the scanning unit of the processing apparatus transfers the tomographic data. A surgery support system, which displays a tomographic image of the scan section based on the obtained tomographic data. 3. The surgery support system according to claim 1, wherein the measurement of each tomographic data in the volume data and the measurement of the tomographic data of the scan section are performed by the same measuring method. Surgery support system.