JPH0435647A - Magnetic resonance imaging (mri) device - Google Patents

Abstract

PURPOSE:To set a slice easily and accurately by providing a control means or the like to control an inclined magnetic field wave form and an RF signal wave form depending on the set slice. CONSTITUTION:When an instruction is delivered to correct the direction, the position, and the like of a slice, by operating a keyboard device 43 and a mouse 44, a slice figure to show the slice after correction is displayed on the screen of a CRT display device 42. And by repeating such an operation, optimum and accurate slice setting can be made. And when a number of slice setting relating to the left and the right optic nerves are finished, inclined magnetic field wave forms and RF signal wave forms corresponding to a number of setting are found by a computer 41, and they are set in wave form generating circuits 31 and 33. After that, by carrying out a multi-angle scanning, the data of the set numerous slices are collected, and picture images as to the set numerous slices can be obtained simultaneously.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an MRI apparatus that obtains images using nuclear magnetic resonance (NMR).

[Conventional technology]

2. Description of the Related Art Conventionally, in MRI apparatuses, an imaging method (usually referred to as multi-angle scan) has been used in which data is collected from a plurality of non-parallel slices at once and images thereof are obtained. This multi-angle scan is very useful because it allows data to be collected from multiple non-parallel slices at once. In other words, even for a large number of regions of interest in the human body that are not necessarily parallel, such as intervertebral discs, images of the large number of intervertebral discs can be obtained at once with a -degree scan.
Imaging time is shortened, making it extremely useful. In this case, conventionally, for each large number of slices, the direction
The position, thickness, etc. are set.For example, the settings for each slice are made by displaying the MR image positioning image obtained in advance on the screen and moving the slice shape etc. on the image. .

[Problem to be solved by the invention]

However, setting the direction, position, thickness, etc. for each slice as in the conventional method is inefficient and takes time. In view of the above, it is an object of the present invention to provide an improved MRI apparatus that allows slice settings to be easily and accurately performed by focusing on the fact that slice settings can be categorized for each diagnostic site.

[Means to solve the problem]

In order to achieve the above object, the MRI apparatus according to the present invention includes a static magnetic field generating means, a means for generating a gradient magnetic field of a predetermined waveform, a means for exciting an RF multiplied signal of a predetermined waveform to the subject, and means for receiving an NMR signal of;
means for configuring an image by processing data obtained from the received NMR signal; an image display means for displaying the image; and a storage means for storing initial values regarding predetermined slices for each diagnostic region. , reads out this initial value, displays it as a slice figure corresponding to the slice on the screen of the image display means, overlaps it with the positioning image, corrects the displayed slice figure by correcting the above initial value, and determines the position of the slice. - It is characterized by having a slice setting means for setting the direction and thickness, and a control means for controlling the above-mentioned gradient magnetic field waveform and RF signal waveform based on the set slice.

[For production]

When displaying a positioning image and setting a large number of slices in order to perform a multi-angle scan of a certain region, the initial value of the set slice for that region is read from the storage means, and a figure representing the slice indicated by the initial value information is read out. is displayed superimposed on the positioning image. When a modification regarding a set slice is instructed, the initial value is modified and the slice figure is modified to represent the modified slice. Therefore, by observing this,
You can check whether the slices have been set optimally. If the slice settings are not optimal, a modification is instructed again, the modified slice figure is displayed, and by repeating this process, the optimal slice settings can be easily reached. The initial values regarding the set slices are determined in advance and stored in the storage means so that only slight modifications are required when setting a large number of slices for each region. Therefore, only a small amount of modification is required, which facilitates complex setting work for a large number of slices for multi-angle scanning, and enables accurate setting.

【Example】

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an MRI apparatus according to an embodiment of the present invention, in which a subject 1 is placed in a static magnetic field space created by a static magnetic field generating magnet 21. A gradient magnetic field generating coil 22 and a transmitting/receiving coil 23 are arranged in this space. A current is supplied to the gradient magnetic field generation coil 22 from a gradient magnetic field power supply 32, and a gradient magnetic field for slice selection, a gradient magnetic field for reading (frequency coding), and a gradient magnetic field for phase coding are generated. Signals from the waveform generation circuit 31 are sent to a gradient magnetic field power supply 32 to determine the waveforms of these gradient magnetic fields. On the other hand, an RF multiplied signal having an envelope according to the waveform sent from the waveform generating circuit 33 is sent from the RF transmitting circuit 34.
The signal is sent to the transmitting/receiving coil 23, and the subject 1 is irradiated with an RF signal. The NMR signal generated in the subject 1 is received by the transmitting/receiving coil 23, detected by the receiving/detecting circuit 35, and then
The signal is sampled by the A/D converter 36 and converted into a digital signal, which is then input to the computer 41. This computer 41 controls gradient magnetic field waveforms and RF signal waveforms, controls gradient magnetic field and RF signal generation timing, controls data sampling timing, etc., and processes the captured data to form an image. Connected to the computer 41 are a CR7 display device 42, a keyboard device 43, and a mouse 44 (or other position input device such as a trackball). The above obtained image is displayed by the CR7 display device 42. This computer 41 also includes a slice setting memory 4.
5 is connected. This slice setting memory 45 stores initial value information regarding slice settings for each scheduled diagnosis site. In other words, the areas imaged by multi-angle scanning are usually the vertebrae, left and right optic nerves, knee joints, etc. The settings for the many slices in these can be categorized as shown in Figure 2 for the vertebrae. In the case of the left and right optic nerves, the results are as shown in Figure 3, and in the case of the knee joints, the results are as shown in Figure 4. Therefore, information on the initial values (such as those shown in Figures 2, 3, and 4) regarding the slices set for each region is obtained in advance, and these are stored in the memory 4.
It is stored in 5. These initial values are required so that slice settings for each region can be easily performed with only slight modifications later. Here, assuming that a multi-angle scan is performed to diagnose the left and right optic nerves, the slice settings will be explained. First, as shown in FIG. 5, the transverse image of the head obtained in advance with this MRI apparatus is
2, and then the slice setting program is started on the computer 41. And memory 45
The initial slice setting value for the optic nerve (FIG. 3) is read from , and the slice figure representing the slice indicated by the information is displayed on the screen of the CR7 display device 42 as shown in FIG. 5. An instruction is given to modify the direction, position, etc. of the slice by operating the keyboard device 43 or the mouse 44. Information regarding the modified slice is then stored in another section of the memory 45, and along with this, the modified slice A slice figure representing the left and right optic nerves appears on the screen of the CR7 display device 42. By repeating this process, optimal and accurate slice settings can be made. Gradient magnetic field waveforms and RF signal waveforms corresponding to the settings are determined and set in the waveform generation circuits 31 and 33. Thereafter, when a multi-angle scan is executed, data is collected for the large number of slices set. , images of a large number of set slices can be obtained simultaneously. Also, when imaging the vertebrae by multi-angle scanning, the sagittal image of the male portion obtained in advance is
After displaying it on the screen of the display device 42, the initial value information of the set slice as shown in FIG. , make the same modifications as above and set the optimal slice. When performing imaging of the M joint using multi-angle scanning, the transverse image of the knee joint obtained in advance is
After displaying it on the screen of the R7 display device 42, the initial value information of the set slice as shown in FIG. 4 is read from the memory 45, and the slice figure corresponding to the slice is displayed superimposed on the sagittal image of the male part Then, make corrections in the same way as above to set the optimal slice. Note that here, the operator reads out the initial value information of the set slice from the memory 45 according to the part to be imaged.
The corresponding initial value information may be configured to be automatically read. Additionally, in the process of imaging various parts using multi-angle scanning, it is also possible to retain the set slice information and store it as an initial value when you want to use it later. It is. This allows the operator to collect and save initial values that are actually useful when setting slices. [Effects of the Invention] According to the MRI apparatus of the present invention, complicated setting work regarding a large number of slices for multi-angle scanning can be facilitated, and moreover, accurate setting can be made. the result,
Overall, the time for imaging can be shortened, the burden on the patient and the operator can be reduced, and the patient throughput of the MRI apparatus can be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIGS. 2, 3, and 4 are diagrams showing initial values of set slices, and FIG.
The figure is a diagram showing the CRT display screen when setting slices. 1... Subject, 21... Static magnetic field generation magnet,
22... Gradient magnetic field generation coil, 23... Transmission/reception coil, 31... Gradient magnetic field waveform generation circuit, 32...
Gradient magnetic field power supply, 33...RF signal waveform generation circuit, 3
4...RF transmission circuit, 35...Reception/detection circuit, 3
6...A/D converter, 41...computer,
42...CRT display device, 43...keyboard device, 44...mouse, 45...slice setting memory.

Claims (1)

[Claims] (1) A static magnetic field generating means, a means for generating a gradient magnetic field with a predetermined waveform, a means for exciting a subject with an RF signal of a predetermined waveform, a means for receiving an NMR signal from the subject, and a received NMR signal. means for configuring an image by processing data obtained from the image processing, and image display means for displaying the image.
a storage means storing initial values regarding set slices predetermined for each diagnostic region; and a storage means for reading out the initial values and displaying them as slice figures corresponding to the slices on the screen of the image display means and superimposing them on the positioning image. , a slice setting means for modifying the displayed slice figure by modifying the initial value and setting the position, direction, and thickness of the slice; An MRI apparatus characterized by having a control means for controlling.