JPH06114033A - Magnetic resonance imaging device - Google Patents

Abstract

PURPOSE:To provide a magnetic resonance imaging device capable of shortening an imaging time including a scanning time and a pretreatment time. CONSTITUTION:A sequencer 10 capable of executing pulse sequence, a computer system 11 controlling the sequencer and performing the signal processing and display of a detection signal, a console 12 and a display device 13 are connected to a magnet assembly MA. The console 12 collects the magnetic resonance data related to the desired three-dimensional area of a subject by executing ultrahigh speed pulse sequence to form a three-dimensional image. A surface ROI is set to the three-dimensional image by the command from the console 12 and superposed on the three-dimensional image as an arbitrary cross section to be displayed on the display device 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to magnetic resonance (MR: magn).
The present invention relates to a magnetic resonance imaging apparatus that obtains a diagnostic image of a subject by utilizing the phenomenon of etic resonance).

[0002]

2. Description of the Related Art The magnetic resonance phenomenon is a phenomenon in which an atomic nucleus having a non-zero spin and magnetic moment placed in a static magnetic field resonantly absorbs and emits only an electromagnetic wave of a specific frequency. Angular frequency ω ₀ (ω ₀ = 2 shown in the following formula
Resonates at (πν ₀ , ν ₀ ; Larmor frequency). ω ₀ = γH ₀ where γ is the gyromagnetic ratio peculiar to the type of nucleus,
H ₀ is the static magnetic field strength.

An apparatus for performing a biomedical diagnosis using the above principle performs signal processing of an electromagnetic wave having the same frequency as that induced after the above-mentioned resonance absorption to obtain a nuclear density, a longitudinal relaxation time T ₁ , and a transverse relaxation time. Diagnostic information reflecting magnetic resonance parameters such as T ₂ , flow, chemical shift, etc., such as a slice image of a subject, is obtained non-invasively.

The collection of diagnostic information by magnetic resonance is capable of exciting all the parts of a subject placed in a static magnetic field and collecting signals. Due to the clinical requirement of the image, an actual apparatus is designed to perform excitation and signal acquisition for a specific site.

In this case, the specific portion to be imaged is generally a sliced portion having a certain thickness, and an echo signal or FI from this sliced portion is generally used.
The magnetic resonance signal (MR signal) of the D signal is collected by executing the data encoding process many times, and these data are collected.
An image reconstruction process is performed on the data group by, for example, a two-dimensional Fourier transform method to generate a tomographic image (slice image) of the specific slice region.

Conventionally, the spin echo method and the field echo method are typical examples of the technique for generating the slice image. With conventional techniques such as the spin echo method and the field echo method, in order to capture one image,
It takes a few seconds at the shortest. Therefore, it is not practical to image a fast-moving part such as the heart. Further, even if the conventional technique is used to perform heart imaging, heartbeat synchronization is required, which requires a longer imaging time, which is a problem. In addition, the time required to determine the photographing surface (cross section) as a pre-processing is also a factor that impedes shortening of photographing.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic resonance imaging apparatus capable of shortening an imaging time including a scanning time and a preprocessing time.

[0008]

In order to solve the above problems and achieve the object, the present invention adopts the following configurations. That is, the invention according to claim 1 causes a magnetic resonance phenomenon to occur in a specific region of the subject by causing a gradient magnetic field to act on the subject placed in a static magnetic field and applying a high-frequency pulse for excitation. In the magnetic resonance imaging apparatus for detecting the induced magnetic resonance signal to obtain the image information of the subject,

A three-dimensional image creating means for collecting magnetic resonance data of a three-dimensional region of a subject by executing an ultrafast pulse sequence to create a three-dimensional image of the three-dimensional region, and the three-dimensional image. A surface ROI creating means for creating at least one desired surface ROI set in the three-dimensional image created by the creating means;

A two-dimensional image of a cross section in the three-dimensional image corresponding to the surface ROI is created based on the three-dimensional image created by the three-dimensional image creating means.
A three-dimensional image creating means, and a display means for displaying an image in which the surface ROI is superimposed on the three-dimensional image and the two-dimensional image created by the two-dimensional image creating means.

According to a second aspect of the present invention, a magnetic resonance phenomenon occurs in a specific region of the subject by applying a gradient magnetic field to the subject placed in a static magnetic field and applying a high frequency excitation pulse. In the magnetic resonance imaging apparatus for obtaining the image information of the subject by detecting the induced magnetic resonance signal,

A three-dimensional image creating means for collecting magnetic resonance data of a three-dimensional region of a subject by executing an ultrafast pulse sequence to create a three-dimensional image of the three-dimensional region, and the three-dimensional image. A surface ROI creating means for creating at least one desired surface ROI set in the three-dimensional image created by the creating means, and a surface ROI moving means for moving the surface ROI.

When the surface ROI is moved by the surface ROI moving means, a two-dimensional image of the cross section in the three-dimensional image corresponding to the moving surface ROI is obtained.
Based on the three-dimensional image created by the three-dimensional image creating means, a two-dimensional image creating means that creates sequentially according to a predetermined movement condition, an image in which the surface ROI is superimposed on the three-dimensional image, and the two-dimensional image creating means. And a display unit for displaying the two-dimensional images sequentially created by.

[0014]

According to the inventions according to claims 1 and 2 configured as above, the three-dimensional region of the subject is scanned for a short time by executing the ultrafast pulse sequence. Then, since an image in which the surface ROI is superimposed on the three-dimensional image is displayed on the display means, the position of the surface ROI to be diagnosed can be easily recognized on the subject shown in the three-dimensional image. Then, under this recognition, the two-dimensional image corresponding to the surface ROI is displayed. In this way, the reduction of the scan time and the reduction of the preprocessing time accompanying the easy setting of the position of the surface ROI are realized.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the overall construction of a magnetic resonance imaging apparatus of the present invention. As shown in FIG. 1, a magnet assembly MA capable of accommodating a subject P therein is a normal-conducting or superconducting system 1 (may be a configuration using a permanent magnet) 1, A gradient magnetic field coil 2 of X, Y, and Z axes for generating a gradient magnetic field for providing position information of a magnetic resonance signal inducing portion,
An RF coil 3 for transmitting a rotating high frequency magnetic field (RF pulse) and detecting an induced magnetic resonance signal (MR signal: echo signal or FID signal). Also,
A static magnetic field control system 4 which controls energization and refrigerant supply control for the static magnetic field generator 1 is connected to the static magnetic field generator 1.

Further, a transmitter 5 for controlling the transmission of RF pulses, a receiver 6 for controlling the reception of induced MR signals, X,
X-axis, Y-axis and Z-axis gradient magnetic field power supplies 7, 8 and 9 for controlling excitation of the Y and Z-axis gradient magnetic field coils 2, respectively, and
A sequencer 10 capable of performing a pulse sequence for data acquisition, and a computer system 1 for controlling these and performing signal processing of a detection signal and display thereof.
1, a console 12 and a display device 13.

The details of the computer system 11 are shown in FIG.
Is shown in. That is, the computer system 11
Is a three-dimensional area position setter 110, a three-dimensional pulse sequence memory 111, and a surface ROI absolute coordinate calculator 112.
A high-definition pulse sequence memory 113, a three-dimensional image reconstruction device 114, a surface ROI display calculator 115, and
Dimensional image reconstruction device 116, first memory 117, second memory 118, third memory 119, and synthesizer 120
And a D / A converter 121. Three-dimensional area position setter 110 and three-dimensional pulse sequence memory 111
The surface ROI absolute coordinate calculator 112 and the high-definition pulse sequence memory 113 are activated by receiving a predetermined command from the console 12, respectively. That is, the console 12 collects magnetic resonance data of a desired three-dimensional region of the subject P by executing an ultrafast pulse sequence by an operation of an operator (not shown), and obtains a three-dimensional image of the three-dimensional region. OP1 which is a command for creating the three-dimensional area position setter 110
And the three-dimensional pulse sequence memory 111. By this command OP1, the operator can set a desired three-dimensional area of the subject P with the help of an illustration displayed on the display device 13, and a three-dimensional pulse sequence memory for three-dimensional imaging of the three-dimensional area. 1
The predetermined three-dimensional pulse sequence is called from 11,
This three-dimensional pulse sequence is given to the sequencer 10. As the three-dimensional pulse sequence, the three-dimensional echo planar method shown in FIGS. 3 and 4 can be adopted. These pulse sequences apply an RF pulse from the RF coil 3 to the subject P by driving the transmitter 5 and detect a magnetic resonance signal from the subject P. Further, the gradient magnetic field power supplies 7, 8 and 9 are driven to apply the gradient magnetic fields Gx, Gy and Gz from the gradient magnetic field coil 2 to the subject P, and the RF coil 3 collects a signal group from the three-dimensional region. And receiver 6
Is given to the three-dimensional image reconstructing device 114 via this, and the three-dimensional image is reconstructed by the data group in the three-dimensional image reconstructing device 114, and the first memory 117, the synthesizer 1
The three-dimensional image is displayed on the display device 13 via the digital camera 20 and the D / A converter 121. In the 3D echo planar method shown in FIGS. 3 and 4, it is assumed that a 3D image with a spatial resolution of 4 mm can be reconstructed into a 64 × 64 × 32 data matrix, and data collection is completed in about 0.5 sec. Shall be able to.

Further, the console 12 sets OP2, which is a command for creating at least one desired surface ROI set in the three-dimensional image, by an operator's operation (not shown), and calculates a surface ROI absolute coordinate calculator. Give to 112. By this command OP2, the operator can determine the surface ROI absolute coordinate calculator 112, the surface ROI display calculator 115, and the second memory 1.
18. The surface ROI can be set on the previously reconstructed three-dimensional image via the synthesizer 120 and the D / A converter 121.
For example, in the case of cardiac imaging, this plane ROI can be set to an arbitrary cross section such as a long axis cross section, a short axis cross section, or a four-chamber cross section. The plane ROI set by the operator is superimposed on the three-dimensional image as an arbitrary cross section, and the superimposed image is displayed on the display device 13. The surface ROI absolute coordinate calculator 112 also supplies the absolute coordinate data regarding the set surface ROI to the three-dimensional image reconstruction device 114. As a result, a data group (cross-section data) regarding the cross section of the set surface ROI is called from the three-dimensional image reconstructing device 114 and given to the two-dimensional image reconstructing device 116, and a two-dimensional image of the cross section is displayed. It is displayed on the device 13.

Further, the console 12 has the surface RO set by the command OP2 by an operation of an operator (not shown).
OP3, which is a command for collecting the magnetic resonance data of the cross section corresponding to I by executing the high-definition pulse sequence and creating a two-dimensional image of the cross section, is given to the high-definition pulse sequence memory 113. By this command OP3, a predetermined high-definition pulse sequence is called from the high-definition pulse sequence memory 113 to two-dimensionally image the cross section, and this high-definition pulse sequence is given to the sequencer 10. As the high-definition pulse sequence, a normal spin echo method or field echo method can be adopted in addition to the two-dimensional echo planar method which is the ultra-high speed imaging technique shown in FIG. These high-definition pulse sequences are driven by the transmitter 5
An RF pulse is applied from the F coil 3 to the subject P, and a magnetic resonance signal is detected from the subject P. Further, the gradient magnetic field power supplies 7, 8 and 9 are driven to apply the gradient magnetic fields Gx, Gy and Gz from the gradient magnetic field coil 2 to the subject P, and the RF coil 3 collects a signal group from the cross section, It is given to the two-dimensional image reconstructing device 116 via the receiver 6, and in the two-dimensional image reconstructing device 116, the two-dimensional image is reconstructed by the data group, and the third memory 119, the synthesizer 120, and The two-dimensional image is displayed on the display device 13 via the D / A converter 121. In the two-dimensional echo planar method shown in FIG. 5, it is assumed that a two-dimensional image having a spatial resolution of 2 mm in a 128 × 128 data matrix can be reconstructed, and the data acquisition can be completed in about 60 msec.

Next, the operation of the magnetic resonance imaging apparatus of the present embodiment configured as described above will be described with reference to the operation flow shown in FIG. That is, in step S1, the operator operates the console 11 and issues a command OP1 from the console 11. As a result, the operator designates a three-dimensional region of the subject P, for example, a heart region, with a cube.

In step S2, the operator operates the console 11 to issue a command OP2 from the console 11. As a result, the cubic region including the previously designated heart region is three-dimensionally scanned.

Thereafter, in step S3, the cubic area is reconstructed by the three-dimensional image reconstructing device 114,
A three-dimensional image 200 as shown in FIG. 7 is displayed on the display device 13.

In step S4, the surface RO is superimposed on the three-dimensional image 200 as shown in FIG.
I201 or a plurality of planes ROI 202, 203 are set. This surface ROI 201 or a plurality of surfaces ROI 202, 2
03 can be arbitrarily set up, down, left and right, rotated, and tilted, and for example, can be set to any cross section such as a long-axis cross section, a short-axis cross section, and a four-chamber cross section of the heart. At this time, in step S5, the coordinates of the surface ROI 201 are calculated, and the coordinate data is used in two ways. One use of the coordinate data is selecting two-dimensional data corresponding to the coordinate data from the three-dimensional image 200 in steps S6, S7, and S8. That is, the selection of this two-dimensional data is for creating a two-dimensional image of an arbitrary cross section based on a three-dimensional image with a spatial resolution of 4 mm, which is a data matrix of 64 × 64 × 32. This step S6, S7, S
The cross section 301 of the heart appeared by 8; 64 × 64 × 32
A tomographic image 250 based on a three-dimensional image having a spatial resolution of 4 mm as a data matrix of is displayed on the screen 13A of the display device 13. The other use of the coordinate data is, in steps S9, S10, and S11, the designation of a two-dimensional region in the subject P to be two-dimensionally imaged by the high-definition pulse sequence. That is, the designation of this two-dimensional area is for performing positioning for imaging a two-dimensional image with a spatial resolution of 2 mm in a 128 × 128 data matrix. This step S9, S10, S11
As a result, a tomographic image 251 that is a two-dimensional image with a spatial resolution of 2 mm in a 128 × 128 data matrix in which the heart cross section 301 appears is displayed on the screen 13A of the display device 13 instead of the tomographic image 250.

As described above, according to this embodiment, the three-dimensional region of the object P is
It will be scanned for a short time. Then, the screen 1 of the display device 13
An image in which the surface ROI 201 is superimposed on the three-dimensional image 200 is displayed on 3A, so that the position of the surface ROI 201 to be diagnosed can be easily recognized on the subject shown in the three-dimensional image 200. , Under this recognition, the surface RO
Two-dimensional images 250 and 251 corresponding to I201 are displayed. In this way, the surface RO
It is possible to shorten the preprocessing time associated with the ease of setting the position of I.

The present invention is not limited to the above embodiment. For example, when one or a plurality of plane ROIs are displayed and they are continuously moved, 3 for each cross section defined by this movement is displayed.
The two-dimensional image 250 based on the three-dimensional image may be reconstructed and displayed. In addition, the present invention can be variously modified and implemented without departing from the scope of the invention.

[0027]

As described above, the invention according to claim 1 is

A three-dimensional image creating means for collecting magnetic resonance data of a three-dimensional region of a subject by executing an ultrafast pulse sequence to create a three-dimensional image of the three-dimensional region, and the three-dimensional image. A surface ROI creating means for creating at least one desired surface ROI set in the three-dimensional image created by the creating means;

A two-dimensional image of a cross section in the three-dimensional image corresponding to the surface ROI is created based on the three-dimensional image created by the three-dimensional image creating means.
A magnetic resonance imaging apparatus comprising: a three-dimensional image creating means; and a display means for displaying an image in which the surface ROI is superimposed on the three-dimensional image and the two-dimensional image created by the two-dimensional image creating means,

The invention according to claim 2 is the same as that of the subject 3
A three-dimensional image creating means for collecting magnetic resonance data about a three-dimensional area by executing an ultrafast pulse sequence to create a three-dimensional image about the three-dimensional area;
Surface ROI creating means for creating at least one desired surface ROI set in the three-dimensional image created by the three-dimensional image creating means, and surface ROI for moving the surface ROI.
I transportation means,

When the surface ROI is moved by the surface ROI moving means, a two-dimensional image of the cross section in the three-dimensional image corresponding to the moving surface ROI is obtained.
Based on the three-dimensional image created by the three-dimensional image creating means, a two-dimensional image creating means that creates sequentially according to a predetermined movement condition, an image in which the surface ROI is superimposed on the three-dimensional image, and the two-dimensional image creating means. And a display unit for displaying the two-dimensional images sequentially created by the magnetic resonance imaging apparatus.

With such a configuration, the three-dimensional region of the subject is scanned for a short time by executing the ultrafast pulse sequence. Then, the surface ROI is set to 3 on the display means.
Since the image superimposed on the three-dimensional image is displayed, it is possible to easily recognize the position of the surface ROI to be diagnosed on the object shown by the three-dimensional image. A two-dimensional image corresponding to is displayed. In this way, the reduction of the scan time and the reduction of the preprocessing time accompanying the easy setting of the position of the surface ROI are realized. Therefore, according to the present invention, it is possible to provide a magnetic resonance imaging apparatus capable of shortening the imaging time including the scanning time and the preprocessing time.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a magnetic resonance imaging apparatus according to an embodiment of the present invention.

FIG. 2 is a detailed block diagram of the computer system in FIG.

FIG. 3 is a diagram showing an example of a pulse sequence of a three-dimensional echo planar method used in the same embodiment.

FIG. 4 is a diagram showing another example of the pulse sequence of the three-dimensional echo planar method used in the same embodiment.

FIG. 5 is a diagram showing an example of a pulse sequence of the two-dimensional echo planar method used in the same embodiment.

FIG. 6 is a flowchart showing the operation of the embodiment.

FIG. 7 is a schematic diagram showing a three-dimensional image in the same example.

FIG. 8 is a schematic diagram showing an example of an image in which a three-dimensional image and a surface ROI are superimposed in the example.

FIG. 9 is a schematic diagram showing another example of an image in which the three-dimensional image and the surface ROI are superimposed in the example.

FIG. 10 is a diagram showing an example in which an image in which a three-dimensional image and a surface ROI are superimposed and a two-dimensional image in the same embodiment are displayed on the same screen.

[Explanation of symbols]

MA ... Magnet assembly, 1 ... Static magnetic field generator,
2 ... X, Y, Z axis gradient magnetic field coils, 3 ... RF coil,
4 ... Static magnetic field control system, 5 ... Transmitter, 6 ... Receiver, 7 ... X-axis gradient magnetic field power supply, 8 ... Y-axis gradient magnetic field power supply, 9 ... Z-axis gradient magnetic field power supply, 10 ... Sequencer, 11 ... Computer system, 12 ... Console, 13 ... Display device, 13A
... Display surface, 110 ... Three-dimensional area position setter, 111 ... 3
-Dimensional pulse sequence memory, 112 ... Plane ROI absolute coordinate calculator, 113 ... High-definition pulse sequence memory, 11
4 ... 3D image reconstruction device, 115 ... Plane ROI display calculator, 116 ... 2D image reconstruction device, 117 ... First memory, 118 ... Second memory, 119 ... Third memory, 120
… Combiner, 121… D / A converter.

Claims (2)

[Claims] 1. A magnetic resonance phenomenon is caused in a specific region of the subject by applying a gradient magnetic field to the subject placed in a static magnetic field and applying a high-frequency pulse for excitation to induce the induced magnetic field. In a magnetic resonance imaging apparatus that obtains image information of a subject by detecting a resonance signal, magnetic resonance data for a three-dimensional region of the subject is collected by executing an ultrafast pulse sequence, and
A three-dimensional image creating means for creating a three-dimensional image of a three-dimensional area, and a surface ROI creating means for creating at least one desired surface ROI set in the three-dimensional image created by the three-dimensional image creating means. A two-dimensional image creating unit that creates a two-dimensional image of a cross section in the three-dimensional image corresponding to the surface ROI based on the three-dimensional image created by the three-dimensional image creating unit; A magnetic resonance imaging apparatus comprising: a display unit configured to display an image superimposed on a three-dimensional image and the two-dimensional image created by the two-dimensional image creating unit. 2. A magnetic resonance phenomenon is caused in a specific region of the subject by applying a gradient magnetic field to the subject placed in a static magnetic field and applying a high-frequency pulse for excitation to induce the induced magnetic field. In a magnetic resonance imaging apparatus that obtains image information of a subject by detecting a resonance signal, magnetic resonance data for a three-dimensional region of the subject is collected by executing an ultrafast pulse sequence, and
A three-dimensional image creating means for creating a three-dimensional image of a three-dimensional area, and a surface ROI creating means for creating at least one desired surface ROI set in the three-dimensional image created by the three-dimensional image creating means. A surface ROI moving means for moving the surface ROI, and a surface ROI moving means for moving the surface ROI,
Two-dimensional image for sequentially creating two-dimensional images of the cross-section in the three-dimensional image corresponding to the moving surface ROI based on the three-dimensional image created by the three-dimensional image creating means according to predetermined moving conditions. A magnetic resonance imaging apparatus comprising: a creating unit; and a displaying unit that displays an image in which the surface ROI is superimposed on the three-dimensional image and the two-dimensional image sequentially created by the two-dimensional image creating unit.