JPH0438419B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Field of Industrial Application) The present invention is directed to magnetic resonance (MR).
The present invention relates to a magnetic resonance diagnostic apparatus that utilizes the resonance phenomenon to obtain diagnostic information that can be used for medical diagnosis, such as slice images of a subject, and particularly relates to a magnetic resonance diagnostic apparatus that can improve diagnostic efficiency.

(Prior art) Magnetic resonance 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. If H ₀ is the static magnetic field strength, then this nucleus resonates at the angular frequency ω ₀ shown in the following equation.

The method of performing biological diagnosis using the principle of ω ₀ = γH ₀ or more is as follows:
The electromagnetic waves of the same frequency as those induced after the above-mentioned resonance absorption are subjected to signal processing to obtain, for example, a tomographic image of the subject.

In this case, the collection of diagnostic information by magnetic resonance is
Although it is possible to excite and collect signals from all parts of a subject placed in a static magnetic field, due to limitations in the device configuration and clinical requirements for imaging images, in reality it is only possible to excite and collect signals from specific slice parts. I am trying to collect signals.

Next, a specific imaging operation in such a magnetic resonance diagnostic apparatus will be described with reference to an example in which screening diagnosis of the abdomen is performed. That is,
The subject is set on the bed, and the tabletop is moved to place the subject's abdomen in the diagnosable area within the magnetic pedestal. Then, the surgeon sets the imaging area such as slice position and slice thickness by key-in etc. on the console, and also sets the imaging pulse sequence such as SE method, SR method, IR method and its time by key-in etc. on the console. Set and further 128×128, 128×
Set the matrix number, such as 256, 256×256, 512×512, etc., by keying in on the console.

When the setting of these imaging parameters is completed, the surgeon turns on the imaging switch.
As a result, photographing is performed using the photographing parameters set above. Then, the slice image is displayed on the display after the data collection time and reconstruction time corresponding to the imaging parameters have elapsed.

Next, in order to change the imaging area such as the slice position and slice thickness, the operator sets a new imaging area such as the slice position and slice thickness by key-in or the like on the console. At this time, the operator turns on the imaging switch when he has completed setting imaging parameters different from the previous one by changing the imaging pulse sequence or changing the number of matrices as necessary.

As a result, imaging is performed using imaging parameters different from the previous imaging. Then, after the data acquisition time and reconstruction time corresponding to the new imaging parameters have elapsed, the slice image is displayed on the display. By repeating this procedure,
It will be possible to perform screening diagnosis.

As described above, in the conventional magnetic resonance diagnostic apparatus, the imaging parameters once set before starting imaging cannot be changed during imaging, which poses a problem in terms of imaging efficiency.

That is, let us consider an example of a photographing operation in which the photographing area is sequentially changed, the photographed image is observed, and the next photographing area is set based on the observation result. In this example, we are using a typical image capture system where the imaging time (the time required from applying the magnetic field to displaying the image) is several minutes or more.
In a scan that executes an imaging pulse sequence using the SE method, the previous imaging that is the basis for changing the imaging parameters is one that lasts for more than ten minutes, and the "imaging time>> imaging parameters are set. "The time required to do so." For this reason, it is not necessary to change the shooting parameters during shooting, and even if you change them after shooting, it takes a long time to shoot in the first place, so the time required to set shooting parameters is added. Even if this happens, it does not pose much of a problem in terms of imaging efficiency per unit time.

However, when performing real-time scanning, which has been developed recently, as soon as you set the shooting parameters and operate the shooting switch, you can obtain an image from the previous shooting that serves as the basis for changing the shooting parameters. The fact that the parameters cannot be changed during imaging is a problem because imaging takes a short time, and if the time required to set the imaging parameters is added, the imaging efficiency per unit time decreases, which is a problem.

(Problem to be Solved by the Invention) In the conventional technology, the shooting parameters once set before starting shooting cannot be changed during shooting. In this case, the photographing efficiency per unit time decreases, which is a problem.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a magnetic resonance diagnostic apparatus that improves imaging efficiency per unit time.

[Structure of the Invention] (Means for Solving the Problems) The present invention is characterized by taking the following measures in order to solve the above problems and achieve the object. That is, the present invention provides a gradient magnetic field for providing position information and a gradient magnetic field for providing position information to a subject placed in a static magnetic field by activating a controller based on imaging parameters that define at least one of an imaging area and an imaging pulse sequence. In a magnetic resonance diagnostic apparatus that applies a high-frequency magnetic field for excitation and collects the induced magnetic resonance signals in a data acquisition system to generate a slice image and display it on a display, the imaging parameters are transmitted to the data acquisition system. The present invention is characterized in that it includes an imaging parameter input means that can be set sequentially by a manual operation of an operator independently of the controller, and the controller is sequentially activated according to the imaging parameters set by this means.

(Function) According to this configuration, the imaging parameters can be set sequentially by the operator manually operating the imaging parameter input means, and the controller is sequentially activated according to the sequentially set imaging parameters, so that the imaging parameters can be set sequentially during imaging. This makes it possible to prepare for photographing with desired photographic parameters even when the camera is in use.

(Embodiment) An embodiment of the magnetic resonance diagnostic apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of a magnetic resonance diagnostic apparatus according to this embodiment.

As shown in FIG. 1, the magnet mount 1 includes a static magnetic field magnet 2 made of either a superconducting magnet, a normal conducting magnet, or a permanent magnet for generating a static magnetic field, and an X, Y, It has a gradient magnetic field coil 3 that generates a gradient magnetic field along the Z-axis direction, and a probe coil 4 that generates a high frequency magnetic field for excitation. In addition, a bed (not shown) is provided, and the patient P is set on this bed, and the top board is moved so that the desired imaging region of the patient P, for example, the abdomen, is placed in the uniform static magnetic field within the magnet mount 1. It is now possible to place it in a diagnosable area of space.

Also, a static magnetic field control system 5 that performs excitation control and coolant supply control for the static magnetic field magnet 2, and a gradient magnetic field coil 3.
A gradient magnetic field power supply 6 supplies excitation current to the coils for each of the X, Y, and Z axes, and a high-frequency current for excitation is supplied when the probe coil 4 functions as a transmitting coil, and a high-frequency current for excitation is supplied when the probe coil 4 functions as a receiving coil. It includes a transceiver 7 that receives and processes detected magnetic resonance signals.

The gradient magnetic field power supply 6 and the transmitter/receiver 7 are driven by a sequencer 8, and this sequencer 8 is used to perform imaging pulse sequences such as the normal SE method.
It is now possible to execute a real-time imaging pulse sequence with an imaging time of a few seconds or less.

The computer system 9 is connected to the console 10, and gives commands to the sequencer 8 to drive the gradient magnetic field power supply 6 and the transceiver 7 based on certain imaging parameters based on the imaging command given by the surgeon, and also to the transceiver 7. The magnetic resonance signals received by the scanner are collected and a slice image or the like is generated using an image reconstruction method such as a Fourier transform method. Here, the imaging parameters include imaging parameters related to the imaging region such as slice position and slice thickness, and imaging parameters related to the imaging pulse sequence.

The console 10 includes, for example, a display 10A capable of performing multi-frame display, and a trackball 10B for setting slice positions by parallel translation in this example as imaging parameters, and the slice position which is a feature of this embodiment. It is now possible to perform arbitrary settings and normal operation commands. The display 10A and the track ball 10B are arranged, for example, in close proximity so that the same operator can observe and operate them. Also, track ball 10B
Instead, it is possible to use a coordinate input device such as a joy stick or a mouse that is easy to operate and allows continuous coordinate input.

When the trackball 10B for setting the slice position is operated, the analog output S is generated at each predetermined interval.
is captured as parallel movement distance data of the slice position, and the imaging parameter setting unit 11 that has received this data generates data corresponding to the parallel movement distance of the slice position. The computer system 9 updates only the imaging parameters related to the slice position that have been changed and creates new imaging parameters (the imaging parameters related to the slice position are updated, the imaging parameters related to slice thickness are unchanged, and the imaging parameters related to the imaging pulse sequence are updated. (without any change) and provides this to the sequencer 8.

The operation of this embodiment configured as described above is performed as an example of performing abdominal screening diagnosis, that is, as shown in FIG.
4. An example in which slice images are continuously captured and displayed in S5 will be described. That is, the subject is set on the bed, and the tabletop is moved to place the abdomen of the subject P in the diagnosable area within the magnetic pedestal 1.

Then, the operator sets the slice thickness by key-in etc. on the console 10, sets the slice position (initial setting S1) by key-in etc. on the console 10, and sets the real-time imaging pulse sequence on the console 10. The number of matrices is set by key-in or the like on the console 10.

When the setting of these imaging parameters is completed, the surgeon turns on the imaging switch.
As a result, photographing is performed using the photographing parameters set above. Then, the gradient magnetic field power source 6 and the transmitter/receiver 7 are activated according to the real-time imaging pulse sequence, and the
A gradient magnetic field along the Y and Z axes and a high-frequency magnetic field for excitation are applied to the subject P, and the magnetic resonance signal from the position S1 of the subject P shown in FIG. 2 is received and processed, and the display is displayed. A slice image is displayed on 10A.

When the operator rolls the track ball 10B to the other side, for example, with the intention of observing the slice image at this position S1 and the slice images at other positions, as shown in FIG. A trackball output S appears. The imaging parameter setting unit 11 captures the data by time sampling, for example, and recognizes the captured output as parallel movement distance data of the slice position. That is, the parallel movement distance data h1 is obtained after a time Δt, and the parallel movement distance data h2 is obtained after a time T corresponding to the photographing time is set and then a time Δt. By performing this sequentially, the parallel movement distance data h1, h2, h3,
h4 can be obtained.

This parallel movement distance data h1, h2, h3, h
The computer system 9 that has received the data h1, h2, h3, and h4 calculates imaging parameters regarding slice positions indicating positions S2, S3, S4, and S5 in FIG. 2 in correspondence with the data h1, h2, h3, and h4. Here, only the imaging parameters related to the changed slice position are updated and new imaging parameters are created (imaging parameters related to the slice position are updated, imaging parameters related to slice thickness are unchanged, and imaging parameters related to the imaging pulse sequence are unchanged). and gives it to the sequencer 8.

As a result, positions S1, S2, S3, and
Slice images S4 and S5 are displayed as multi-slices on the display 10A.

In the above, the shooting parameter setting section 11 captures the trackball output S by time sampling to obtain parallel movement distance data. In this case, as shown in FIG. The period of time T during which the photographing parameters are not changed is a period during which the photographing parameters are prohibited, and the time T corresponding to the same photographing time is the period during which photographing is being performed, as shown in FIG. 3c.

As described above, according to this embodiment, the imaging parameters regarding the slice position can be sequentially changed by operating the track ball 10B, and the imaging parameters changed by this operation can be sequentially executed. Therefore, it becomes possible to change the imaging parameters related to the slice position even during imaging. Therefore, it becomes possible to set the desired slice image at any position while observing the displayed image. In particular, when an image is displayed immediately after shooting starts, such as in real-time scanning, the shooting operation and parameter setting operation operate independently.
It becomes possible to display slice images at desired positions one after another, which improves imaging efficiency per unit time, which is advantageous.

Of course, even if you execute a shooting pulse sequence that takes more than ten minutes of shooting time instead of a real-time shooting pulse sequence, you can change the shooting parameters during shooting, so even if the shooting time is long, This is almost equivalent to not adding the time required to set the imaging parameters for each unit of imaging, so the imaging efficiency per unit time is improved.

In the above example, it is assumed that the unit imaging is to obtain one slice image, but when data of multiple slice images is obtained and the data is averaged to obtain one slice image. It may be.
In this case, it is necessary to set the number of additional images when setting the initial shooting parameters.

In the above embodiment, the imaging parameters to be changed are specified only to the parallel movement of the slice position. The imaging parameters related to the imaging pulse sequence including the above may be sequentially changed as desired by the operator.
In this case, instead of providing a coordinate input device for each imaging parameter that needs to be changed, a single coordinate input device may be provided and the coordinate input device may be switched and used as appropriate.

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 is equipped with an imaging parameter input means that can sequentially set imaging parameters by manual operation of the operator independently of the data collection system, and the imaging parameters set by this means are By configuring the controller to be activated sequentially, the imaging parameters can be set sequentially by the operator manually operating the imaging parameter input means, and the controller is activated sequentially based on the sequentially set imaging parameters, so that there are no errors during imaging. Even if there is a problem, it is possible to prepare for photographing using desired photographing parameters.

Therefore, according to the present invention, it is possible to provide a magnetic resonance diagnostic apparatus that improves imaging efficiency per unit time.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an embodiment of the magnetic resonance diagnostic apparatus according to the present invention, FIG. 2 is a diagram showing an example of an imaging operation, and FIG. 3 is a diagram illustrating an operation for changing imaging parameters in the same embodiment. This is a diagram. DESCRIPTION OF SYMBOLS 1... Magnet mount, 2... Static magnetic field magnet, 3... Gradient magnetic field coil, 4... Probe coil, 5... Static magnetic field control system, 6... Gradient magnetic field power supply, 7... Transmitter/receiver, 8... Sequencer, 9...computer system, 10...console, 10A...display, 10B...track ball, 11...imaging parameter setting unit.

Claims (1)

[Claims] 1. A gradient magnetic field for imparting position information to a subject placed in a static magnetic field by activating a controller based on imaging parameters that define at least one of an imaging area and an imaging pulse sequence. and a magnetic resonance diagnostic apparatus in which a high-frequency magnetic field for excitation is applied and the induced magnetic resonance signals are collected by a data acquisition system to generate a slice image and displayed on a display, the imaging parameters are determined by the data acquisition system. A magnetic resonance diagnosis characterized in that the controller is configured to include an imaging parameter input means that can be set sequentially by a surgeon's manual operation independently of the system, and to sequentially activate the controller according to the imaging parameters set by this means. Device. 2. The magnetic resonance diagnostic apparatus according to claim 1, wherein the display and the imaging parameter input means are arranged in such a manner that they can be observed and operated by the same person. 3. The magnetic resonance diagnosis according to claim 1 or 2, wherein the controller is configured to be able to execute a real-time imaging pulse sequence in which the time required from application of a magnetic field to image display is approximately several seconds or less. Device.