JPH03121049A - Magnetic resonance imaging device - Google Patents

Abstract

PURPOSE:To take a photograph of an image which is useful in medical therapy by holding the variation characteristic data of the texture contrast due to the difference at least in the photographing condition or photographed part and displaying the variation characteristic data, together with the photographed image, at least either before or after photographing. CONSTITUTION:A data memory means 14 for holding the variation characteristic of the texture contrast due to the difference in either the photographing condition or the photographed part and a display means 12 for displaying the variation characteristic data, together with a photographed image either before or after photographing. Since an operator can inspect the variation characteristic data of the texture contrast due to the difference at least in either the photographing condition or photographed part, together with the photographed image either before or after photographing, the condition setting and image observation can be caried out after the photographing condition and the contrast in the texture are easily grasped.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to magnetic resonance (MR) technology.
The present invention relates to a magnetic resonance imaging method and apparatus for obtaining morphological information and functional information such as spectroscopy of a subject using the phenomenon (sonance).

(Prior art) Magnetic resonance is a phenomenon in which an atomic nucleus with non-zero spin and magnetic moment placed in a static magnetic field resonantly absorbs and emits only electromagnetic waves of a specific frequency. The angular frequency ω0 (ωo−2πν., ν0
; Larmor frequency).

ω0−γH.

Here, γ is the gyromagnetic ratio specific to the type of atomic nucleus,
Further, Ho is the static magnetic field strength.

An apparatus that performs biological diagnosis using the above-mentioned principle processes electromagnetic waves of the same frequency as the above induced after the above-mentioned resonance absorption, and calculates nuclear density, longitudinal relaxation time T7. Transverse relaxation time T2. Diagnostic information that reflects information such as flow and chemical shift, such as slice images of a subject, can be obtained non-invasively.

Collecting diagnostic information by magnetic resonance can excite all parts of a subject placed in a static magnetic field and collect signals, but there are limitations in the equipment configuration and clinical requirements for imaging images. Therefore, in an actual device, a specific part is excited and its signal is collected.

In this case, the specific region to be imaged is generally a sliced region with a certain thickness;
Magnetic resonance signals (MR multiplied signals) of echo signals and FID signals from this slice site are collected by performing a data encoding process many times, and these data groups are subjected to image reconstruction processing using, for example, a two-dimensional Fourier transform method. By doing so, an image of the specific slice region is generated.

When imaging each part of the subject, a group of tissue-specific parameters in magnetic resonance imaging (nuclear density, longitudinal relaxation time T1, transverse relaxation time T2, flow, chemical shift, etc.) and a parameter group under imaging conditions ( Imaging method, high frequency pulse, echo time TE, pulse repetition time TR
etc.), so depending on the imaging conditions and site selection,
The contrast of the captured image changes significantly.

For example, FIG. 4(a) is a schematic diagram of an axial image of the head when the pulse echo method is used, and the echo time T is 30 m5ec and the pulse repetition time TR is 250 m5ec. FIG. 2 is a schematic diagram of an axial image of the head when the pulse echo method is used and the echo time Tg is 30 msec and the pulse repetition time TR is 3000 m5ec. In this way, by changing the TR, the contrast of the photographed image changes significantly.

(Problem to be solved by the invention) Conventionally, in consideration of the above, clinical information has been obtained by envisioning the imaging conditions and tissue contrast in mind, or by performing imaging while looking at the imaging guide. . Therefore, there have been problems such as not being able to obtain satisfactory images due to lack of knowledge or unfamiliarity with the settings, and the inspection taking time.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a magnetic resonance imaging apparatus that can easily capture clinically useful images.

[Structure of the Invention] (Means for Solving the Problems) The present invention has a structure in which the following means are taken to solve the above problems and achieve the objects.

That is, a magnetic resonance phenomenon is caused in a specific part of the subject, and the magnetic resonance phenomena caused by the phenomenon are collected to determine nuclear density, longitudinal relaxation time T1. Transverse relaxation time T2. In a magnetic resonance imaging apparatus that generates and displays image information based on magnetic resonance parameters such as flow and chemical shift, data holding means holds data on changes in tissue contrast due to differences in at least one of imaging conditions and imaging regions; The present invention is characterized by comprising means for displaying the change characteristic data together with the photographed image at least one of prior to photographing and after photographing.

(Function) According to such a configuration, the operator can view tissue contrast change characteristic data due to differences in at least one of the imaging conditions and the imaging site together with the captured image at least one of prior to and after imaging. Therefore, it is possible to easily understand the imaging conditions and tissue contrast before setting conditions and observing images.

(Example) An example of a magnetic resonance imaging apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of the magnetic resonance imaging apparatus of this embodiment, and FIG. 2 is a pulse sequence diagram of the imaging method executed by the magnetic resonance imaging apparatus of this embodiment.
FIG. 3 is a diagram showing a display example, and FIGS. 5 and 6 are characteristic diagrams as changing characteristic data.

In FIG. 1, there is a static magnetic field magnet 2. A gradient magnetic field coil 1 that generates gradient magnetic fields along the X, Y, and Z axis directions, and a probe 4 having transmitting and receiving coils are incorporated, and a space (not shown) into which a subject is introduced is formed inside these. At the same time, the generated magnetic field within the space makes it possible to generate magnetic resonance phenomena and collect magnetic resonance signals.

Further, the gradient magnetic field coil 3 is driven by a gradient magnetic field controller 5 and an amplifier 6, and the probe 4 is driven by a transmitter 7.
．． It is driven by receiver 8. Gradient magnetic field controller 5
．． Transmitter 7. The receiver 8 is under the control of a sequencer 9, which in turn is under the control of a computer system 10.

And probe 4. The magnetic resonance signals obtained through the receiver 8 are transmitted to the computer system 1 via the memory 11.
0, where image reconstruction processing is performed using two-dimensional and three-dimensional Fourier transform methods, and display is performed on the display 12.

Further, the sequencer 9 can execute various imaging methods, such as the pulse echo method shown in FIG. 2, and the settings thereof can be performed using the console 13. It also has a data memory 14, in which characteristic diagrams as change characteristic data shown, for example, in FIGS. 5 and 6 are stored. FIG. 5 shows changes in the contrast of each tissue in the head when the pulse repetition time TR is varied while the echo time T8 is constant. FIG. 6 shows changes in the contrast of each tissue in the head when the pulse repetition time TR is constant and the echo time T8 is varied.

In the spin echo method shown in Figure 2, Gs represents a gradient magnetic field for slicing, G3 represents a gradient magnetic field for reading, GE represents a gradient magnetic field for phase encoding, and Hl represents a gradient magnetic field for phase encoding. H2 is a high frequency pulse for refocusing the magnetization during excitation, generally with a flip angle of around 90°, and H2 is a high frequency pulse for refocusing magnetization during excitation, generally with a flip angle of around 180°. It is something.

According to the configuration described above, the operator can view tissue contrast change characteristic data due to differences in at least one of the imaging conditions and the imaging site prior to imaging, and thereby the operator can check the imaging conditions and the tissue contrast. Conditions can be set based on an easy understanding of the

Furthermore, as shown in FIG. 3, after imaging, it is possible to view the change characteristic data GI together with the photographed image Sl, so it is possible to easily understand the imaging conditions and tissue contrast before observing the image.

This improves inspection efficiency.

In addition, various modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] As described above, the present invention provides a data holding means for holding tissue contrast change characteristic data due to differences in at least one of the imaging conditions and the imaging site, and a data storage means for holding the change characteristic data before and after imaging. By having a means for displaying at least one of the captured images together with the captured image, the operator can display tissue contrast change characteristic data due to differences in at least one of the capturing conditions and the captured region.
Since it can be viewed together with the photographed image at least one of prior to and after photographing, it is possible to easily grasp the photographing conditions and tissue contrast before setting conditions and observing the image.

Therefore, according to the present invention, it is possible to provide a magnetic resonance imaging apparatus that can easily capture clinically useful images.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the magnetic resonance imaging apparatus of the present invention, FIG. 2 is a pulse sequence diagram executed by the magnetic resonance imaging apparatus of this embodiment, and FIG. 3 is a display example. Figure 4 is a diagram showing that the contrast differs depending on the parameter, Figures 5 and 6 are
The figure is a characteristic diagram as change characteristic data. DESCRIPTION OF SYMBOLS 1... Main body, 2... Static magnetic field magnet, 3... Gradient magnetic field coil, 4... Probe, 5... Gradient magnetic field controller, 6... Amplifier, 7... Transmitter, 8・・・
-Receiver, 9...Sequencer, 10...Computer system, 11...Memory, 12...Display, 13...Console, 14...Data memory.

Claims (1)

[Claims] A magnetic resonance phenomenon is generated in a specific part of the subject, and the magnetic resonance phenomena generated by the phenomenon are collected to determine the nuclear density,
In a magnetic resonance imaging apparatus that generates and displays image information based on magnetic resonance parameters such as longitudinal relaxation time T_1, transverse relaxation time T_2, flow, and chemical shift, changes in tissue contrast due to differences in at least one of imaging conditions and imaging regions. A magnetic resonance imaging apparatus comprising: a data holding means for holding characteristic data; and a means for displaying the changing characteristic data together with a photographed image at least one of prior to and after photographing.