JPH01291851A - Magnetic resonance imaging device - Google Patents

Abstract

PURPOSE:To enable a measuring condition to be easily set by reading information of a card, which stores the measuring condition, and controlling a pulse sequence for nuclear magnetic resonance by this information. CONSTITUTION:A card 11, in which a proper measuring condition of pulse sequence or the like is stored in memory in addition to attribute information of every detected person, is created. The information, stored in memory in this card 11, is read by a card read/write device 6, and the measuring condition of pulse sequence or the like for a nuclear magnetic resonance phenomenon is transmitted to a control unit 8. Simultaneously, the information is displayed in a display 10. After this display is confirmed, an MRI unit 3 is actuated, obtaining a tomographic image.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic resonance imaging apparatus, and particularly to an operation control technique suitable for handling complex pulse sequences.

[Prior art]

Conventionally, in magnetic resonance imaging (hereinafter referred to as MRI), images with enhanced longitudinal relaxation time T1 and transverse relaxation time T2 are obtained by applying high-frequency pulses called 90'' and 180' pulses and gradient magnetic fields (hereinafter referred to as pulse sequence). Figure 4 shows the longitudinal relaxation time T of the human body. Figure 4 shows the relaxation when the amounts of each component are the same. Actually,
Since the abundance ratio of each component is different, it becomes even more complicated.

In Figure 4, fat (A) has a fast relaxation time.

It slows down in white matter (b) and gray matter (c), and slowest in cerebrospinal fluid (d). In other words, the measurement time (echo time T
It can be seen that the magnitude of the obtained tissue difference signal differs depending on which part of a, Tb, Tc) is taken.

A signal I□ obtained by the spin echo method (SE method) generally obtained by MRI is expressed by equation (1).

r,,=M, eXp (-TE/T2) [1-ex
p (-Ta/T1) ]"' (1) Mo=density T6: echo time T2: transverse relaxation time T: longitudinal relaxation time T,: repetition time In equation (1), if T is large, signal I.

It can be seen that depends on exp (-TE/T2).

Also, the signal 1□ by the inversion recovery method (IR method) is (2)
It is shown by the formula.

I, =M, exp (-T, /T2) [1-2e
xp (-TX/Tt)+exp(-T□/T□)]・
...(2) T, : Inversion time From equation (2), in the inversion recovery method, the signal is 8XP (
It can be seen that it depends on T r /T x ).

In addition to these two methods, there is also a saturation recovery method (SR method) that more closely reflects the density.

In this way, in MR imaging, the pulse sequences used for measurement (SE, IR, SR, etc.) and their parameters (diagnostic site, visual field, pulse repetition time (TR), echo time (TE), inversion time (TI), Depending on the number of measurement matrices, number of additions, slice thickness, number of slices, etc.
Since image density and contrast vary greatly, it is important to select the optimal pulse sequence depending on the nature of the lesion. These pulse sequences and parameters are manually selected and set one by one using a keyboard on the console.

[Problem to be solved by the invention]

However, with conventional devices, as mentioned above, the selection and setting of a large number of measurement conditions is manually set one by one using the keyboard each time the subject changes, which is time-consuming and can lead to input errors. There was a problem that. Further, there is a problem that the operation is complicated.

Furthermore, in MR imaging, the contrast of images is greatly influenced by measurement parameters.

It is necessary to select the optimal measurement parameters depending on the disease. For this reason, it is meaningful to set the previous measurement conditions for repeat patients, but conventional devices have a problem in that they cannot systematically handle information about each individual.

The present invention has been made to solve the above problems.

The object of the present invention is to provide a magnetic resonance imaging apparatus with:
The object of the present invention is to provide a technique that allows easy setting of a wide variety of complex measurement conditions for nuclear magnetic resonance.

Another object of the present invention is to provide a technique that can improve reliability in a magnetic resonance imaging apparatus without making any operational errors during input.

Another object of the present invention is to provide a technology that can easily handle optimal pulse sequences according to symptoms and can ensure reproducibility of optimal pulse sequences in a magnetic resonance imaging apparatus. It is in.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a static magnetic field.

In an MHI device that causes nuclear magnetic resonance in a subject using a gradient magnetic field and a high-frequency magnetic field, and receives this nuclear magnetic resonance signal to reconstruct an image, a card reading device installed on a console, etc., and a pulse sequence etc. The main features include a card storing measurement conditions and means for reading the information stored on the card and controlling the pulse sequence for nuclear magnetic resonance using this information.

Further, the present invention is characterized in that a card writing device is added to the card reading device to record measurement conditions such as the pulse sequence.

[Effect]

According to the above-mentioned means, for example, a card is created for each patient in which unique measurement conditions such as pulse sequences are stored in addition to the patient's attribute information, and the information stored in this card is read out from the card. The information is read by the device, and in addition to the attribute information of the subject, measurement conditions such as a pulse sequence for nuclear magnetic resonance (NMR) phenomena are transferred to the control device. At the same time, the relevant information is displayed on the operation desk for the inspector to confirm.

On the other hand, when it is necessary to change the parameters of the measurement conditions, the inspector changes them using the console.

As a result, the pulse sequence control device becomes 90' 1
Generation of an irradiation pulse of 80' pulse or X.

The generation of gradient magnetic fields in three directions of y and z is controlled to cause a desired nuclear magnetic resonance phenomenon. As a result, the saturated recovery image (SR)
Various tomographic images such as , T□, and T2 weighted images can be obtained.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be specifically described using the drawings.

In addition, in all the figures for explaining the embodiment, parts having the same functions are given the same reference numerals, and repeated explanations thereof will be omitted.

FIG. 1 is a block diagram showing a schematic system configuration of an MRI apparatus according to an embodiment of the present invention, and FIG. 2 is an external view showing the overall configuration of an MHI apparatus.

As shown in FIGS. 1 and 2, the MHI device of this embodiment includes a bed 1 for placing a patient, a magnetic circuit gantry section 2 that causes a nuclear magnetic resonance (NMR) phenomenon, a device that generates a high-frequency signal, The MRI unit 3 amplifies and detects the received weak signals and generates the gradient magnetic field signals necessary for imaging, and the pulse sequence control unit 3 performs image reconstruction calculations and controls the pulse sequence of nuclear magnetic resonance phenomena. It is composed of an image processing device 4. Reference numeral 5 is a multi-format camera for making a film of the reproduced image, 6 is a card reading/writing device, 7 is an operation console, 8 is a pulse sequence control device, 9 is an arithmetic device, and 10 is a CRT display.

In FIGS. 1 and 2, when performing an examination, the subject is placed on the patient bed 1, and the top plate of the patient bed 1 is placed inside the magnetic circuit. go. Place the area you want to photograph approximately in the center of the space with a uniform magnetic field. A card in which the measurement sequence and parameters to be photographed are stored is set in the card reading/writing device 6 on the operation console 7. Based on this data, the pulse sequence control device 8
The power supply of the high frequency magnetic field and gradient magnetic field in the IRI unit 3 is controlled to generate a desired high frequency magnetic field and gradient magnetic field in the examination space in the magnetic circuit gantry section 2. Thereby, a nuclear magnetic resonance (NMR) signal generated by the subject is detected by the receiving coil in the magnetic circuit gantry section 2, amplified and detected by the MHI unit 3, and sent to the arithmetic unit 9. Here, image reconstruction calculation processing is performed, and the reconstructed image is displayed on the CRT display 10.

As mentioned above, MRI images vary greatly depending on the pulse sequence used for measurement and its parameter conditions.
Symptom 9: It is necessary to set the optimal conditions for each condition depending on the tissue properties, etc.

In this embodiment, in order to set the pulse sequence conditions, as shown in FIG. Card 11 in which unique measurement conditions of
, and use the information stored in this card 11. That is, the information stored in the card 11 is
Reading or writing is performed by a card reading/writing device 6 on the pulse sequence control and image processing device 4.

Here, a specific example of the contents of the measurement conditions stored in the card 11 is shown in FIG. This card 11 uses, for example, a magnetic floppy disk, an optical disk, a nonvolatile random access memory (RAM), or the like.

In Figure 3, PNO is the protocol number (NO)
This can be applied to cases, etc. FOV
is the imaging field (+n+), THICK is the slice thickness (a+m), and GAP is the slice gap (mm).
, TR is the repetition time (ms) of the irradiation pulse,
~TE4 is multi-echo time (ms), TI is inversion time (ms), MULT is number of multi-slices, N
SA is the number of additions used for average addition, and MATRIX is the number of measurement projections.

Next, one embodiment of the pulse sequence control/image processing device 4 will be described in detail with reference to FIG.

In Figure 1, card reading/writing (read/write)
The device 6 performs reading/writing processing of information stored on the card 11 and transfers the information on the card 11 to the arithmetic device 9 . The information transferred to the arithmetic device 9 is sent to a CRT display 10 provided on the operation console, and displays information including the attributes of the patient and the measurement conditions of the pulse sequence. At the same time, the arithmetic device 9 transfers the pulse sequence measurement conditions sent from the card 11 to the pulse sequence control device 8. The pulse sequence control device 8 generates control signals for irradiation pulses and gradient magnetic fields according to the sent pulse sequence measurement conditions,
Transfer to MHI unit 3. The MRI unit 3 generates irradiation waveforms and gradient magnetic field waveforms based on the sent signals, and applies them to the irradiation coil and gradient magnetic field coil in the magnetic circuit gantry section 2 to generate irradiation magnetic fields and gradient magnetic fields, respectively. do.

The nuclear magnetic resonance (NMR) signal generated thereby is received by a receiving coil in the magnetic circuit gantry section 2,
Sent to MHI unit 3. In MHI unit 3,
This signal is amplified and sent to the arithmetic unit 9 for image reconstruction. The reconstructed image is sent to the CRT display 10 and displayed as a tomographic image.

Furthermore, when capturing an image with different measurement conditions, the examiner changes the measurement conditions displayed on the CRT display 10 from an operation console or the like. Even under these changed conditions, image reconstruction is performed using the same procedure as described above.

Further, after the measurement is completed, if the used pulse sequence is stored in the card 11 by the card reading/writing device 6, new measurement conditions can always be automatically set next time.

In the above-mentioned embodiment, a method was described in which the card 11 is controlled based on information that corresponds to each individual. It is also possible to store the measurement conditions for each person and the measurement conditions for each laboratory technician and use them for general purposes.

As can be seen from the above description, according to this embodiment, the card reading/writing device 6 is provided on the operation console 7, and the card reading/writing device 6 measures the pulse sequence etc. stored in the card 11. By providing the pulse sequence control/image processing device 4 that reads the conditions and controls the pulse sequence for magnetic resonance based on the measurement conditions,
The pulse sequence control/image processing device 4 is 90'1
The generation of irradiation pulses of 80' pulses and the generation of gradient magnetic fields in three directions of x, y, and z are controlled to cause a desired nuclear magnetic resonance phenomenon. The result is a saturated recovery image (SR).

T, various tomographic images such as 12-weighted images can be obtained.

This makes it possible to easily set a wide variety of complex measurement conditions for nuclear magnetic resonance.

Furthermore, reliability can be improved without any operational errors during input.

Further, it is possible to easily handle the optimum pulse sequence according to the symptom, and the reproducibility of the optimum pulse sequence can be ensured.

Although the present invention has been specifically described above based on examples, it goes without saying that the present invention can be modified in various ways without departing from the gist thereof.

〔Effect of the invention〕

As described above, according to the present invention, a wide variety of complicated measurement conditions for magnetic resonance can be easily set using a simple card.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a schematic system configuration of an MRI apparatus according to an embodiment of the present invention, FIG. 2 is an external view showing the overall configuration of the MHI apparatus shown in FIG. 1, and FIG. A diagram showing a specific example of the contents of the measurement conditions stored in the card shown in the figure, FIG.
FIG. 3 is a relaxation time explanatory diagram for explaining a problem with the device. In the figure, 1... Patient bed, 2... Magnetic circuit gantry section, 3... MRI unit, 4... Pulse sequence control/image processing device, 5... Multi-format camera, 6 ...Card reading/writing device, 7...
Operation console, 8...Pulse sequence control device, 9...
Arithmetic device, 10... CRT display, 11...
card.

Claims (2)

[Claims] (1) In a magnetic resonance imaging device that causes nuclear magnetic resonance in a subject using a static magnetic field, a gradient magnetic field, and a high-frequency magnetic field, and receives this nuclear magnetic resonance signal to reconstruct an image,
A card reading device installed on an operation console, a card storing measurement conditions such as a pulse sequence, and means for reading information stored in the card and controlling a pulse sequence for nuclear magnetic resonance using this information. A magnetic resonance imaging device comprising: (2) Adding a card writing device to the card reading device,
The magnetic resonance imaging apparatus according to claim 1, wherein measurement conditions such as the pulse sequence are stored.