JP3911602B2 - Magnetic resonance imaging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic resonance imaging apparatus, and more particularly to a technique for controlling an imaging surface by following the movement of an invasive device such as a catheter inserted into a living body of a subject while performing continuous imaging.
[0002]
[Prior art]
A magnetic resonance imaging (MRI) apparatus excites nuclei at a desired measurement site in a living body, and forms an image of the measurement site in the living body based on a nuclear magnetic resonance signal (NMR signal) generated by the excitation. This device is used for diagnosis. Usually, to excite nuclei, a high frequency magnetic field pulse is irradiated in a state where a uniform static magnetic field is applied to a living body. In addition, in order to obtain a two-dimensional tomographic image of the measurement site, a gradient magnetic field having a gradient in the orthogonal three-axis directions is applied to give positional information of the two-dimensional space to the NMR signal. A control procedure for capturing an MR image of a desired part by controlling the timing of irradiation of these high-frequency magnetic field pulses, application of a gradient magnetic field, sampling of an NMR signal, and the strength of the gradient magnetic field is called a pulse sequence. It is determined by the imaging sequence.
[0003]
As such an imaging sequence, in addition to basic methods such as a spin echo method and a gradient echo method, an echo planer (EPI) method and a fast spin echo (FSE) method are used as a high-speed imaging method. , Etc. are proposed. This FSE method is a method realized as a practical high-speed sequence having an image quality close to that of the conventional SE method by dividing the conventional RARE method into a plurality of sequence sequences. Here, the RARE (rapid acquisition with relaxation enhancement) method is a method in which a large amount of echo signals (NMR signals) are generated by repeating inversion by radio frequency (RF) of transverse magnetization generated by excitation by a 90 ° pulse. This is an imaging sequence in which a multi-echo method for generating the image is applied and different phase encodings are given to the respective echo signals so that one image can be obtained at high speed. On the other hand, the EPI method is a method of acquiring a plurality of echo signals with one excitation pulse by inverting the readout gradient magnetic field at high speed without using RF inversion. According to this EPI method, high-speed imaging of several tens of ms is possible, but it is extremely sensitive to non-uniform static magnetic fields.
[0004]
By applying these high-speed imaging sequences, a real-time dynamic imaging method called fluoroscopy (perspective imaging) is being applied to clinical practice. Fluoroscopy repeats short-time imaging of about 1 second or less and real-time image reconstruction, and is used to visualize the dynamics of internal tissues and to insert an invasive device such as a catheter from outside into the body as if it were X-ray fluoroscopic imaging. It can be used for grasping the position of. In particular, recently, in order to minimize the invasiveness to a patient, an application in intraoperative imaging generally called an interventional MRI (I-MRI) is being performed.
[0005]
The most promising application of fluoroscopy in I-MRI is an imaging means for guiding an invasive device such as a puncture needle or a catheter to an affected area. Since normal two-dimensional imaging cannot detect the three-dimensional position of the catheter, it is difficult to obtain information such as the traveling direction. In this regard, a method for three-dimensionally detecting the position and direction of the catheter is described in the literature “Magnetic Resonance in Medicine 44, pp. 56-65 (2000), Active MR Guidance of Interventional Devices. With Target-Navigation ”. According to this, a plurality of RF receiving coils are embedded at intervals in the longitudinal direction of the catheter, the catheter approaching direction is detected based on the MR images of those coils, and the detected catheter approaching direction and the affected part, etc. MR images for navigation are performed by automatically determining a scan section including the position of the tissue. In other words, the imaging section is determined so as to always include the target tissue and the catheter, so that the catheter is not lost.
[0006]
[Problems to be solved by the invention]
However, the active guide method of the catheter described in the above document detects the position and direction of the catheter after imaging three orthogonal cross sections (for example, X, Y, and Z cross sections) twice, and then the target tissue. The actual scanning imaging is performed by determining the imaging section including the catheter and the catheter. That is, since the catheter tracking and the navigation image are divided into two stages and imaged by the time division method, there is a time lag until the catheter is detected, and there is a problem in the real-time property as navigation, which is not practical.
[0007]
An object of the present invention is to realize navigation with excellent real-time performance that can follow an invasive device to be tracked without losing sight.
[0008]
[Means for Solving the Problems]
The present invention solves the above problems by the following means. First, according to the present invention, an imaging sequence for collecting an echo signal generated by excitation by applying a high-frequency pulse and a gradient magnetic field to a subject placed in a static magnetic field space and collecting the echo signals generated by the excitation is collected. A magnetic resonance imaging apparatus that reconstructs a two-dimensional or three-dimensional image of a desired part of the subject based on an echo signal and continuously displays the reconstructed image on a display is used as a basic means.
[0009]
A feature of the present invention is based on a reconstructed image using an invasive device provided with at least two singular points that are separated from each other in the MR image at a distance in the longitudinal direction of the invasive device and become a unique image. In addition, a singular point of the invasive device to be inserted into the subject is detected, and a invasive device detecting means for detecting the position of the invasive device and the three-dimensional approach direction by obtaining the direction of the straight line connecting the two singular points is provided. There is.
[0010]
In the case of an imaging sequence that captures a two-dimensional image, the invasive device detection means can obtain the direction of a straight line connecting singular points by the three-axis cross-sectional image by capturing orthogonal three-axis cross-sectional images. Here, the triaxial cross-sectional image is, for example, a horizontal cross-section (COR), a vertical vertical cross-section (SAG), and a vertical cross-section (TRS) of a lying patient. By the way, if the approach direction does not change, it is possible to track with an orthogonal biaxial cross-sectional image, and there is no need to capture a triaxial cross-sectional image. Therefore, the imaging time can be shortened by switching the imaging sequence. In addition, by using a triaxial cross-sectional image, if an invasive device is detected in one axial cross-sectional image, the position information is fed back to correct the imaging region by the next imaging sequence, thereby improving the followability. It can be improved. That is, the invasive device is not lost at all, and if the approximate position is known, the detailed position can be understood from the axial cross-sectional image.
[0011]
In the case of an imaging sequence for imaging a three-dimensional image, the invasive device detection means can determine the direction of a straight line connecting singular points from a projection image obtained by projecting the three-dimensional image onto a plane including three orthogonal axes. The projection image can be obtained by a known maximum value projection process (MIP).
[0012]
As described above, according to the present invention, since the approach direction of the invasive device that changes three-dimensionally can be detected, the invasive device to be tracked can be detected even if the approach direction of the invasive device changes three-dimensionally. Follow without losing sight. In addition, since the invasive device is tracked by the same imaging sequence as the imaging scan, navigation with excellent real-time characteristics can be realized.
[0013]
In addition, the singular point is formed by, for example, embedding a small RF receiving coil in the distal end portion of the invasive device, or a marker made of a low signal material such as a magnetic material or a high signal material is mixed in the resin of the catheter. Can be formed.
[0014]
The magnetic resonance imaging apparatus of the present invention uses the position or traveling direction of the invasive device detected by the invasive device detection means to change to an imaging cross section or imaging region including the target site for invasive device guidance and the invasive device. Navigation means for changing the gradient magnetic field condition of the imaging sequence can be provided. In this case, without taking an image for detecting the position of the invasive device as in the conventional example, the tissue image and the blood vessel image are continuously captured, and the image information is fed back to detect the position and the traveling direction of the invasive device. can do. According to this, since the imaging time and the image processing time can be shortened, the real-time property of navigation for guiding the invasive device to the target site can be improved. In this case, a tissue image and a blood vessel image around the target site are captured and stored before surgery, and a tracking image of the invasive device is superimposed on the image to display the navigation image for guiding the invasive device to the target site. Real-time performance can be further improved.
[0015]
[Embodiment]
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram illustrating an embodiment for detecting a catheter approach direction which is an example of an invasive device using a triaxial cross-sectional image according to a feature of the present invention. FIG. 2 is an overall block diagram of a magnetic resonance imaging apparatus to which the present invention can be applied. FIG. 3 is a perspective view showing an example of a catheter. FIG. 4 is a schematic diagram showing a state of the catheter inserted into the blood vessel. FIG. 5 is a diagram showing an example of an imaging sequence used in the present invention.
[0016]
As shown in FIG. 2, the magnetic resonance imaging apparatus includes a static magnetic field generating magnet 2, a gradient magnetic field generating system 3, a sequencer 4, a transmitting system 5, a receiving system 6, a signal processing system 7, a central processing unit (CPU) 8, and the like. It is configured with. The static magnetic field generating magnet 2 generates a uniform static magnetic field in the space where the subject 1 is placed. The direction of the static magnetic field is usually the body axis direction of the subject 1 or the direction perpendicular to the body axis. The static magnetic field generating magnet 2 is formed by using a permanent magnet, a normal conducting material, or a superconducting magnet. In the static magnetic field space surrounded by the static magnetic field generating magnet 2, the gradient magnetic field coil 9 of the gradient magnetic field generating system 3, the high frequency coil 14a of the transmission system 5, and the high frequency coil 14b of the reception system 6 are installed. The gradient magnetic field generating system 3 includes a gradient magnetic field coil 9 that generates a gradient magnetic field in three orthogonal axes (X, Y, Z), and a gradient magnetic field power supply 10 that supplies a drive current for the gradient magnetic field coil 9. Has been. The gradient magnetic field power supply 10 applies gradient magnetic fields Gx, Gy, Gz in three orthogonal axes (X, Y, Z) directions to the subject 1 in accordance with instructions from the sequencer 4. The slice plane of the tomographic image can be set by applying this gradient magnetic field.
[0017]
The sequencer 4 operates under the control of the CPU 8 and repeatedly applies a high-frequency magnetic field pulse that causes nuclear magnetic resonance to the atomic nucleus constituting the living tissue of the subject 1 in accordance with an imaging sequence called a predetermined pulse sequence. Is. In addition, a command is sent to the gradient magnetic field generation system 3, the transmission system 5, the reception system 6, and the like, and the control necessary for capturing a tomographic image is executed.
[0018]
The transmission system 5 irradiates a high frequency magnetic field pulse to cause nuclear magnetic resonance to occur in the nucleus constituting the living tissue of the subject 1 under the control of the sequencer 4, and includes a high frequency oscillator 11, a modulator 12, a high frequency amplifier 13, and It has a high frequency coil 14a. Then, the transmission system 5 modulates the amplitude of the high frequency pulse output from the high frequency oscillator 11 by the modulator 12 and amplifies it by the high frequency amplifier 13 in accordance with an instruction from the sequencer 4, and then supplies the high frequency pulse to the high frequency irradiation coil 14a. The subject 1 is irradiated with a pulse (RF pulse).
[0019]
The receiving system 6 detects an echo signal (NMR signal) emitted by nuclear magnetic resonance of the nucleus of the living tissue of the subject 1, and receives the high-frequency coil 14b, the amplifier 15, the quadrature detector 16 and A on the receiving side. A / D converter 17 is provided. The magnetic resonance signal received by the high-frequency coil 14 b is amplified by the amplifier 15, detected by the quadrature detector 16, and then converted into digital signal measurement data by the A / D converter 17. The two series of measurement data sampled by the quadrature detector 16 at the timing controlled by the sequencer 4 is sent to the signal processing system 7. It should be noted that a plurality of receiving systems 6 are provided, the signals received by the respective receiving coils (high-frequency coils) are combined, and the image is reconstructed to improve the S / N ratio or to capture an image with a wide field of view. Can be possible.
[0020]
The signal processing system 7 includes a CPU 8, a magnetic disk 18, a magnetic tape 19, and a display 20 such as a CRT. The CPU 8 performs an image reconstruction process including a Fourier transform process on the measurement data input from the reception system 6, creates a signal intensity distribution of an arbitrary cross section or an image having a predetermined process, and displays it on the display 20 as a tomographic image. It is supposed to be. The magnetic disk 18 and the magnetic tape 19 record image data reconstructed by the CPU 8. The display 20 converts the image data stored in the magnetic disk 18 and the magnetic tape 19 into an image and displays it as a tomographic image. Further, the signal processing system 7 has a function of performing difference processing and weighting on image data as a function of the CPU 8. Selection and setting of these processes are performed via an input means (not shown) of the CPU 8. In addition, the display 20 has a function of displaying a difference image or a cumulative addition image instead of a normal image or in addition to a normal image, corresponding to the function of the signal processing system 7.
[0021]
In the present embodiment, the tracking function for tracking the catheter 21 which is an invasive device inserted into the body of the subject 1, which is the feature of the present invention, and the operator's insertion operation by displaying the tracking result on the image of the display 20. The CPU 8 has a navigation function for guiding. Further, in order to improve the drawing performance of the catheter, the catheter 21 is provided with two receiving coils 22a and 22b, and echo signals received by them are taken into the CPU 8 via the receiving system 23, and image In a process such as reconstruction, the image is combined with the image of the reception system 6.
[0022]
Next, the configuration related to the tracking and guidance of the catheter 21 using the magnetic resonance imaging apparatus of the above embodiment will be described together with the operation. FIG. 3 shows a schematic diagram of the catheter 21. The catheter 21 of the present embodiment is formed in a cylindrical shape that can be inserted into a blood vessel, and two receiving coils 22a and 22b are embedded at a distal end thereof with a space therebetween. The interval between the receiving coils 22a and 22b is typically 3 to 5 cm. The echo signals received by the receiving coils 22a and 22b are transmitted to the receiving system 23 through a signal line (not shown).
[0023]
The subject 1 is placed in the measurement space in the static magnetic field of the magnetic resonance imaging apparatus, and the catheter 21 is inserted through the blood vessel 25 to the required treatment site as shown in FIG. In the insertion process, for example, an MR image is acquired in accordance with an imaging sequence based on the multi-shot EPI method shown in FIG. FIG. 5 shows, in order from the top, a high-frequency pulse RF, a slice gradient magnetic field Gs, a phase encoding gradient magnetic field Gp, a readout gradient magnetic field Gr, and an echo signal Signal. The horizontal axis represents time, and the vertical axis represents intensity. As shown in the figure, this imaging sequence is excited by the radio frequency pulse RF101 while applying the slice gradient magnetic field pulse 102. The high-frequency pulse RF101 has an appropriate flip angle α ° of 90 ° or less. Next, after applying the phase encoding gradient magnetic field pulse 103 and the gradient magnetic field pulse 104 in the readout direction, the readout gradient magnetic field pulses 105, 106 and 107 are repeatedly applied while being inverted, and a plurality of echo signals 108, 109 and 110 are applied. measure. Also, blips 111 and 112 are applied in the phase encoding direction between the readout gradient magnetic field pulses 105 and 106 and between the readout gradient magnetic field pulses 106 and 107 to shift the phase encoding of those echo signals. Such an imaging sequence is repeated at a repetition time TR, and an echo signal necessary to form one image is measured. Now, TR is 10 ms, the echo interval TE is 4 ms, the FOV is 260 mm, the number of data in the readout direction is 128, the phase encoding amount is 120, the number of shots is 40, and the number of echo trains is 3 (108 to 110 in FIG. 6). When set, the update time of one two-dimensional image can be reduced to about 0.4 seconds (10 × 120/3 = 400 ms). Subsequently, the slice gradient magnetic field pulse 202 and the phase encode gradient magnetic field pulse 203 are applied and the gradient magnetic field pulse 204 in the readout direction is applied, and the imaging sequence for acquiring the next image is repeated.
[0024]
Such an EPI imaging sequence is repeatedly executed, and a two-dimensional or three-dimensional image is acquired by performing image reconstruction such as Fourier transform on the measured echo signal. Meanwhile, the signal processing system 7 stores the data of each echo signal in each frame memory, performs maximum value projection (MIP) processing in three-dimensional (3D) imaging, and continuously displays time-series images.
[0025]
Next, an embodiment for detecting the position and traveling direction of the catheter 21 based on the MR image captured as described above will be described. First, when the catheter 21 exists in the imaging region, a two-dimensional image as shown in FIG. 4 is displayed. However, the direction of the catheter 21 is not known from one two-dimensional image. Therefore, in the present embodiment, using the imaging sequence in FIG. 5, first, imaging is performed using a three-axis cross section, for example, a three cross section including the X axis, the Y axis, and the Z axis as slice axes. The time required for this imaging is 0.4 seconds × 3 cross sections = 1.2 seconds in the above example. A perspective view showing the concept of an image including the catheter 21 imaged in this way is shown in FIG. In FIG. 1, (A) is a TRS image 31 which is a tomographic image along the Z axis, (B) is a SAG image 32 which is a tomographic image along the Y axis, and (C) is a tomographic image along the X axis. A COR image 33 is shown. These drawings are shown in consideration of the slice thickness of the imaging region. As shown in these figures, in the obtained image, the portions corresponding to the receiving coils 22a and 22b of the catheter 21 are singular points P1 and P2 in the respective images, and are images with brightness significantly different from the other portions. Is displayed. Based on the three-axis cross-sectional image, the CPU 8 detects the position and the traveling direction of the catheter. For example, the inclination θx, θy, θz formed by the straight line connecting the singular point P1 and the singular point P2 in each image and each axis X, Y, Z is geometrically calculated, and these angles are combined to form a three-dimensional view. The direction of travel can be determined. When obtaining the three-dimensional traveling direction, it is convenient to use a well-known polar coordinate system or cylindrical coordinate system. In addition, the entire advancing direction of the catheter indicated by an arrow in the figure is detected by comparing images captured in time series.
[0026]
As described above, in the present embodiment, the three-dimensional cross-sectional image of the two-dimensional I-MRI image is captured by the same imaging sequence as the imaging scan, and the catheter position and traveling direction can be detected in three dimensions from these images. In addition, since it can be detected at intervals of 1.2 seconds, navigation with excellent real-time performance can be realized. That is, the CPU 8 outputs, for example, a command for automatically changing the imaging conditions such as the slice position and the slice direction to the sequencer 4 according to the detected catheter position and the traveling direction, so that the target is not lost on the image. It can be guided to the site.
[0027]
In the state where the traveling direction of the catheter does not change greatly, it is less likely that the catheter will be missed without taking a three-axis cross-sectional image. In this case, the detection time can be shortened and the real-time property can be further improved by detecting the position and traveling direction of the catheter based on the biaxial cross-sectional image. In addition, by using a triaxial cross-sectional image, if an invasive device is detected in one axial cross-sectional image, the position information is fed back to correct the imaging region by the next imaging sequence, thereby improving the followability. It can be improved. In other words, the invasive device is not lost at all, and if the approximate position is known, the detailed position is known from the axial cross-sectional image.
[0028]
Next, another embodiment of the present invention for detecting the position and traveling direction of the catheter 21 while capturing a three-dimensional I-MRI image will be described with reference to FIGS. FIG. 6 is an example of three-dimensional imaging of a target region including a catheter, and schematically shows a state where the catheter 21 is inserted into the blood vessel 25. Based on the image data of the three-dimensional image, the CPU 8 performs projection processing of a three-axis cross section, and performs maximum value projection processing (MIP) that constitutes an image with the maximum value pixels. Thereby, the COR image 41, the SAG image 42, and the TRS image 43 shown in FIGS. 7A, 7B, and 7C are obtained. FIG. 4D is an example of a composite image 44 in which the detected singular points P1 and P2 of the catheter are superimposed on the tomographic image including the target portion imaged before insertion of the catheter. These images are MPR (Multi Planar Projection) images.
[0029]
The CPU 8 detects the position and traveling direction of the catheter based on the COR image 41, the SAG image 42, and the TRS image 43 in FIG. For example, as shown in FIGS. 8A and 8B, the inclinations θx, θy, and θz formed by the straight lines connecting the singular points P1 and P2 in each image with the axes X, Y, and Z are geometrically represented. The three-dimensional traveling direction S (θx, θy, θz) can be obtained by calculating and synthesizing these angles. Here, for the sake of easy understanding, the description has been made using the orthogonal coordinate system, but it is generally convenient to use a known polar coordinate system when obtaining the three-dimensional traveling direction.
[0030]
Also in this embodiment, if the number of three-dimensional I-MRI imaging slabs (number of slices) is set to three, the MIP image of the catheter, the position, and the traveling direction every 1.2 seconds as in the above example. Can be continuously obtained and displayed. Moreover, you may obtain | require and display on the image the distance which the catheter advanced, and the advancing speed as needed.
[0031]
Also, if the user can variably set parameters such as TR / TE of the imaging sequence, slice direction, number of slabs, and other conditions to the CPU 8 via the input means, the measurement site and situation during I-MRI can be set. By the determination, for example, a navigation image having a preferred slice direction and contrast can be displayed.
[0032]
Further, in the above description, the description has focused on detecting the position and traveling direction of the catheter, but the present invention is not limited to this, and the imaging position is automatically changed according to the user's setting. Further, navigation imaging means for imaging while following the catheter can be provided. That is, navigation means for changing the gradient magnetic field condition of the imaging sequence is provided in order to change the imaging section or imaging region including the target site and the catheter using the detected position and traveling direction of the catheter. In this case, the tissue image can be continuously imaged without imaging for catheter position detection as in the conventional example, and the image information can be fed back to detect the catheter position and traveling direction. Therefore, since the imaging time and the time for image processing can be shortened, the real-time property of navigation for guiding the catheter to the target site can be improved. In particular, a tissue image around the target site is captured and stored before surgery, and the tracking image of the catheter is superimposed on the tissue image and displayed, thereby ensuring real-time navigation for guiding the catheter to the target site. Meanwhile, the visibility of the I-MR image can be improved.
[0033]
In the above embodiment, the receiving coil embedded in the catheter may be a small loop coil or a linear coil. Further, instead of the receiving coil, a marker made of a low signal material or a high signal material such as a magnetic material may be attached to the catheter or mixed with the catheter resin. In short, it is only necessary to provide at least two singular points that form a peculiar image that can be distinguished from other parts in the MR image with an interval in the longitudinal direction of the catheter.
[0034]
Further, the catheter has been described as an example of the invasive device. However, the present invention is not limited to this, and the present invention can be applied to tracking and navigation of a device that is inserted into the body such as a puncture needle.
[0035]
【The invention's effect】
As described above, according to the present invention, it is possible to follow the invasive device to be tracked without losing sight, and to realize navigation with excellent real-time properties.
[Brief description of the drawings]
FIG. 1 is a schematic diagram for explaining an embodiment in which a catheter approach direction, which is an example of an invasive device, is detected using a triaxial cross-sectional image according to a feature of the present invention.
FIG. 2 is an overall block diagram of a magnetic resonance imaging apparatus to which the present invention can be applied.
FIG. 3 is a perspective view showing an example of a catheter.
FIG. 4 is a schematic diagram showing a state of a catheter inserted into a blood vessel.
FIG. 5 is a diagram showing an example of an imaging sequence used in the present invention.
FIG. 6 is a perspective view schematically showing an I-MR image obtained by three-dimensional imaging of a target region including a catheter.
7 is an example of a composite image in which a COR image, a SAG image, a TRS image, and singular points P1 and P2 of a catheter obtained by performing a maximum value projection process on the three-dimensional image of FIG. 6 are displayed in an overlapping manner.
FIG. 8 is a schematic diagram for explaining an embodiment for detecting a catheter position and an approach direction based on a COR image, a SAG image, and a TRS image obtained by processing an image of three-dimensional imaging.
[Explanation of symbols]
21 Catheter 22a, 22b Reception coil 25 Blood vessel 31 TRS image 32 SAG image 33 COR image

Claims (8)

Control means for repeatedly executing an imaging sequence for measuring by adding spatial position information to a nuclear magnetic resonance signal generated by exciting the subject, and a magnetic resonance image related to the subject based on the nuclear magnetic resonance signal Image generating means for continuously generating and displaying, and the control means forms at least two pieces of specific image data provided in an invasive device inserted into the subject based on the magnetic resonance image detects the singular points, seeking direction of a straight line connecting said two singular points, with the invasive device detection means for detecting the traveling direction of the position and the three-dimensional of the invasive device, the invasive device detecting means, wherein A magnetic resonance imaging apparatus for detecting a three-dimensional traveling direction of the invasive device from an angle formed by a straight line connecting two singular points and three orthogonal axes . The magnetic resonance imaging apparatus according to claim 1 , wherein the singular point is a small receiving coil. The magnetic resonance imaging apparatus according to claim 2 , wherein the image forming unit includes a signal processing system that processes a signal from the small receiving coil as a signal processing system that processes a nuclear magnetic resonance signal. The magnetic resonance imaging apparatus according to claim 1, wherein the singular point is a marker made of a low signal material or a high signal material.   2. The imaging sequence includes an imaging sequence for imaging orthogonal three-axis cross-sectional images, and the invasive device detection unit obtains a direction of a straight line connecting the singular points by the three-axis cross-sectional images. A magnetic resonance imaging apparatus according to 1.   The imaging sequence includes an imaging sequence for imaging a three-dimensional image, and the invasive device detection means uses the projection image obtained by projecting the three-dimensional image on a plane including any two of three orthogonal axes. The magnetic resonance imaging apparatus according to claim 1, wherein a direction of a straight line connecting the points is obtained. Using the position or direction of travel of the invasive device detected by the invasive device detection means, the imaging is performed so as to change to an imaging section or imaging region including the target site to which the invasive device is to be guided and the invasive device. magnetic resonance imaging apparatus according to any one of claims 1 to 5, characterized in that a navigation means for changing the gradient conditions of the sequence. The control means, a magnetic resonance imaging apparatus according to any one of claims 1 to 6, characterized in that it comprises input means for variably setting a parameter of the imaging sequence.

Images