JPH0543379B2 - - Google Patents

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention collects a group of signals induced by executing a malus slicing method, and then performs reconstruction processing on the collected signal group. The present invention relates to a magnetic resonance imaging apparatus that obtains images, and particularly to a magnetic resonance imaging apparatus that is suitable for photographing a group of reconstructed images with a multiformat camera or the like.

(Prior art) Magnetic resonance (MR) is a phenomenon in which atomic nuclei with non-zero spin and magnetic moment placed in a static magnetic field resonantly absorb and emit only electromagnetic waves of a specific frequency. , this nucleus has an angular frequency ω ₀ (ω ₀ =2πν ₀ ,
It resonates at ν ₀ ; Larmor frequency).

ω ₀ =γH ₀ where γ is the gyromagnetic ratio specific to the type of atomic nucleus, and H ₀ is the static magnetic field strength.

The device that performs biological diagnosis using the above principles is
The electromagnetic waves (magnetic resonance signals: echo signals and FID signals) with the same frequency as above that are induced after the above-mentioned resonance absorption are signal-processed to obtain nuclear density, longitudinal relaxation time constant T1, transverse relaxation time constant T2, flow, and chemical Diagnostic information, such as a slice image of a subject, reflecting information such as shift, etc., is 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. from,
The actual device excites a specific region and collects its signals.

FIG. 3 is a diagram showing the overall configuration of an apparatus capable of implementing this type of magnetic resonance imaging method.

As shown in Fig. 3, a magnet assembly capable of accommodating a subject P therein includes a static magnetic field coil (a static magnetic field correction shim coil is added) using a normal conduction or superconducting method. ) 1, and a gradient magnetic field generating coil 2 for generating a gradient magnetic field (gradient magnetic field pulse) to provide positional information of the induced site of the magnetic resonance signal.
and a rotating high-frequency magnetic field (high-frequency pulse; RF pulse)
It has a probe 3 consisting of a coil, for example, which is a transmission/reception system for transmitting magnetic resonance signals (echo signals, etc.) and detecting the induced magnetic resonance signals (echo signals, etc.), and if it is a superconducting method, it also includes a refrigerant supply control system. a static magnetic field control system 4 that mainly controls the energization of the static magnetic field power source;
7. A transmitter 8, a receiver 9, a sequencer 10 capable of implementing an image data acquisition sequence using, for example, a Fourier transform method as an imaging method, and a computer system CS that controls these and performs signal processing of a detection signal and display thereof. It is configured.

Here, the receiver 9 includes a preamplifier that amplifies the signal from the receiving coil of the probe 3 to the extent that it can be applied to subsequent processing, and performs phase detection on the output of this preamplifier using a real part and an imaginary part, respectively. It includes a phase detector, an A/D converter that converts the output of the phase detector into a digital signal, and an interface that introduces the output of the A/D converter into the computer system CS.

The computer system CS also includes, via a data bus 12, a system controller 11 that performs overall control, and a hard disk magnetic storage device 13 that introduces data from the interface and prepares the data for subsequent reconfiguration processing. , a reconstruction device 14 that reads data from the hard disk magnetic storage device 13 and performs Fourier transform processing on the data to reconstruct images such as Schiano images, two-dimensional images, three-dimensional images, etc.; It is equipped with a man-machine for filing, playback, etc., a console for controlling the interface, a host computer 15 including a filing device, a display 16, and a multi-format camera 17.

With the above configuration, the imaging procedure is to place the subject P in a static magnetic field, operate the sequencer 10, and execute, for example, a spin echo method sequence as a pulse sequence for image data collection.

This drives the transmitter 8, applies an RF pulse (90° pulse) from the transmitting coil of the probe 3, drives the gradient magnetic field power supplies 5, 6, and 7, and generates gradient magnetic fields GX, GY, GZ
, a gradient magnetic field for slicing (GS), a gradient magnetic field for encoding (GS), and a gradient magnetic field for reading (GR), respectively.
In addition, the signal from the specific excitation site is collected by the receiving coil of probe 3 to obtain one line of data in the Fourier space plane.Then, in order to generate one screen, the sequence is repeated a predetermined number of times. The data obtained each time this sequence is executed is transmitted via a data bus 12 to a hard disk magnetic storage device 13 and a reconstruction device 14 to generate, for example, a two-dimensional image, and the reconstructed image is displayed on a display 16. .

The above-mentioned pulse sequence for image data collection is intended to be a sequence for obtaining an image of one slice region, but other pulse sequences for image data collection include multi-image acquisition for multiple regions. A sequence or multi-slice method can be performed to obtain the results.

In such a multi-slice method, for example, when performing N multi-slices on N parts and capturing a group of reconstructed images with a multi-format camera (imager), data collection is performed on N parts. , N echo signals from N locations are stored in the hard disk magnetic storage device 13. By repeating this for the number of reconstruction matrices, a data group from which N slice images can be reconstructed is obtained.

Next, as shown in FIG. 4, in the reconstruction process,
First, the first slice image is reconstructed, then the second slice image is reconstructed, . . . the Nth echo image is reconstructed, and is displayed on a display or stored magnetically.

In the above, the echo signal of the first slice, the echo signal of the second slice, the echo signal of the Nth slice, etc. each have different characteristics such as signal strength, and as a result, the image values also differ. be.

On the other hand, in addition to displaying the reconstructed image on a display or storing it magnetically, the reconstructed image may be photographed using a multi-format camera (imager) 17 or the like, and the photographed photograph may be used for interpretation or stored. In this case, when capturing multiple images using the multi-slice method, the image values of each image are different, so the screen contrast etc. are adjusted each time each image is displayed on the display. Images are taken at the same level and can be interpreted. That is, as shown in FIG.
After the first slice images have been reconstructed, the first slice image is displayed on a display, the contrast of the screen, etc. is adjusted, and then the adjusted image is photographed by the multi-format camera 17. During this photographing time, the next second slice image is displayed on the display, and after adjusting the screen cost and the like, this adjusted image is photographed by the multi-format camera 17. This is repeated up to the Nth slice image, and finally image capturing is completed in which N slice images are imprinted on one or more slice images.

(Problems to be Solved by the Invention) In this way, in the conventional technology, when capturing multiple images using the multi-slice method,
There is a problem in that the contrast of the screen and the like must be adjusted for each image displayed on the display only after a plurality of slice images have been reconstructed, which takes a very long time.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a magnetic resonance imaging apparatus that can reduce the time required to image a plurality of images using a multi-slice method and to file an image file.

[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, the magnetic resonance imaging apparatus according to the present invention is a magnetic resonance imaging apparatus that collects a signal group induced by executing the Mars slicing method and then performs reconstruction processing on the collected signal group to obtain an image. , means for holding screen adjustment values of reconstructed images; The present invention is characterized by comprising a control means for automatically setting screen adjustment based on adjustment values held in the means.

(Function) According to such a configuration, during reconstruction processing, the reconstruction processing for a specific slice region is executed with priority over other regions, and this reconstructed image is displayed on the display, and this first slice region is After adjusting the contrast, etc. of the screen of the slice part, this adjustment value is retained, so the screen adjustment of the reconstructed image of other parts is automatically set according to the retained adjustment value. Only the time and work needed to adjust the screen of the body part is required, and the screen is then automatically adjusted, and the screen-adjusted multi-slice image is captured and an image file is created.

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

The device of this embodiment includes a system controller 11,
A control program 15A is included in a host computer 15 that centrally controls the hard disk magnetic storage device 13 and the reconfiguration device 14.

This control program 15A is programmed so that when a pulse sequence of the multi-slice method is executed, during the reconstruction processing, the reconstruction processing for one specific slice region is executed with priority over other regions. .

The memory 18 is also provided, and this memory 1
8, the above-mentioned control program 15A is executed and the reconstructed image is displayed on the display 1 with priority.
6, and is designed to hold the adjustment value when the operator adjusts the conditions such as the contrast of the display screen to suit the conditions of image capturing.

Further, the control program 15A automatically adjusts conditions such as the contrast of each display screen based on the adjustment values stored in the memory 18 after executing the reconstruction process for other slice parts. has been programmed.

According to the device of this embodiment configured in this way,
When the pulse sequence of the multi-slice method is executed, the control program 15A causes the reconstruction process for a specific slice part to be executed with priority over other parts during the reconstruction process, as shown in FIG. Ru.

Then, this reconstructed image is displayed on the display 16, and when the operator adjusts the conditions such as the contrast of the display screen to match the conditions for image capturing, the adjusted values are held in the memory 18.

Next, as shown in FIG. 2, when reconstruction processing is performed on the sliced parts of other parts, the screen adjustment of the reconstructed image of the other parts is performed based on the adjustment stored in the memory 18. Automatically set depending on the value.

Therefore, according to the present embodiment, only the time and work needed to adjust the screen of the first slice region is required, and the screen is then automatically adjusted, and image capture for this screen-adjusted multi-slice image is performed. It will be done. Therefore, when capturing a plurality of images using the multi-slice method, it becomes possible to perform suitable image capturing while reducing time under approximately appropriate image capturing conditions.

The present invention is not limited to the above-mentioned embodiments, and the adjustment values held in the memory 18 may use empirical values instead of preferentially using measured values related to reconstructed images.

In addition, in the above example, before taking the image,
Although an example of adjusting the reconstructed image is described, it is also applicable to an example of adjusting the reconstructed image before converting it into an image file, and in this case,
This can be realized by changing the control target of the control program 15A to an image file device instead of the multi-format camera 17.

Furthermore, when applied to the three-dimensional Fourier transform method, which requires a long reconstruction time, as a reconstruction method,
It is even more advantageous.

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 includes a means for holding screen adjustment values of a reconstructed image, and a method for performing reconstruction processing for a specific slice region in priority over other regions during reconstruction processing. At the same time, by providing a control means for automatically setting the screen adjustment of reconstructed images of other parts based on the adjustment values stored in the means, it is possible to perform reconstruction processing for a specific slice part during reconstruction processing. , executes with priority over other parts, displays this reconstructed image on the display,
After adjusting the screen contrast etc. of this first slice area, this adjustment value is retained, so
Screen adjustments for reconstructed images of other regions are automatically set based on the retained adjustment values, so you only need time and work to adjust the screen of the first sliced region, and the screen adjustments will be made automatically thereafter. Then, image capturing and image file of this screen-adjusted multi-slice image are performed.

Therefore, according to the present invention, it is possible to provide a magnetic resonance imaging apparatus that can reduce the time required to image a plurality of images using the multi-slice method and to file an image file.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an embodiment of the magnetic resonance imaging apparatus according to the present invention, FIG. 2 is a diagram showing the operation of the same embodiment, FIG. 3 is a diagram showing the configuration of a conventional example, and FIG. FIG. 2 is a diagram showing the operation of the conventional example. 1... Static magnetic field coil, 2... Gradient magnetic field coil,
3... Probe, 4... Static magnetic field control system, 5, 6,
7...Gradient magnetic field power supply, 8...Transmitter, 9...Receiver, 10...Sequencer, 11...System controller, 12...Data bus, 13...Hard disk magnetic storage device, 14...Reconfiguration device ,1
5...Host computer, 15A...Control program, 16...Display, 17...Multi-format camera, 18...Memory.

Claims (1)

[Claims] 1. In a magnetic resonance imaging apparatus that obtains an image by performing reconstruction processing on the collected signal group after collecting a signal group induced by executing the Mars slicing method, screen adjustment values of the reconstructed image are retained. and an adjustment value held in the means for performing reconstruction processing for a particular slice region in priority over other regions during the reconstruction processing, and for adjusting a screen of a reconstructed image of the other region. A magnetic resonance imaging apparatus characterized by comprising a control means for automatically setting based on.