JPH034837A - Magnetic resonance device for diagnosis - Google Patents

Abstract

PURPOSE:To reduce an engineer's burden to the utmost at the time of controlling a scan operation of a device by starting the scan operation of the device by synchronizing with a stop of a body motion of a person to be examined, and stopping the scan operation, when the body motion of the person to be examined is restarted in the course of the scan operation. CONSTITUTION:At the time of performing a scan operation to a person to be examined and collecting a magnetic resonance signal, an instruction is given so as to stop its body motion by operating a voice generating device 18. When the person to be examined stops the body motion by the instruction, the state is detected by an air bag 14, converted to a body motion electric signal by a sensor 15, and thereafter, a gate signal is sent to a computer system 11 through a pre-amplifier 16 and a comparator 17, a sequencer 10 is turned on by synchronizing it with a rise of the gate signal and the scan operation is started. If the body motion of the person to be examined is restarted in the course of the scan operation, the gate signal is varied, and by using it as a trigger, the scan operation is stopped. In such a way, the data collection is performed very satisfactorily and a burden given to an engineer is reduced to the utmost.

Description

[Detailed description of the invention]. [Objective of the Invention] (Industrial Application Field) The present invention relates to a diagnostic magnetic resonance apparatus that images a specific atomic nuclear spin distribution state within a subject by utilizing the magnetic resonance (hereinafter referred to as MR) phenomenon. In particular, the present invention relates to a diagnostic magnetic resonance apparatus suitable for diagnosing a region that involves body movement of a subject.

(Prior Art) As is well known, when a diagnostic MR device collects MR data from a region of the subject that experiences body movement due to breathing, such as the abdomen, the collected data may contain artifact factors. As a result, the quality of the final reconstructed image deteriorates significantly. To deal with this, when collecting data on areas where there is such body movement, a so-called pose scan is generally performed in which the subject is asked to hold their breath. .

Figure 5 shows an example in which the pose scan described above is adopted under so-called 2D multi-slice acquisition, in which data is collected using a pulse sequence to which a two-dimensional Fourier transform method is applied to obtain multi-slice information about the subject. Shown below. That is, during one repetition period of the pulse sequence,
Data for multiple slices (N slices) is collected in time series, and these are phase encoded multiple times (NGE times edge encoded to collect N image data. Here, pose scan is performed for each slice data collection. Insertion is performed multiple times in the phase encoding direction (GE direction) in the middle.

(Problems to be Solved by the Invention) When performing the conventional pose scan described above, as shown in FIG. Smoke it...
...Please just stop. ” he instructs. Next, the condition of the patient is monitored using a monitor, monitoring window, etc., and after confirming that the patient has completed breath-holding, the scanning operation of the device is started at time tl, and for several seconds At time t4, the scanning operation is interrupted and the subject is made to relax by saying, "Please take it easy." The entire scanning operation is completed by repeating this operation a desired number of times.

However, according to the above-mentioned conventional means, the technician visually monitors the patient's breathing situation and starts the scanning operation of the device, so this starting time t1 is not always selected as the optimal time. do not have. Further, when the subject starts breathing during the scanning operation, the scanning operation cannot be stopped, and it becomes impossible to prevent an adverse effect on the reconstructed image. Furthermore, scanning operation control based on the technician's monitoring of the subject needs to be repeatedly performed extremely frequently, which imposes an extremely heavy burden on the technician.

This invention was made in view of the above-mentioned problems, and its purpose is to start the scanning operation of the device in synchronization with the stoppage of body movements of the subject, and to prevent the patient from moving while the device is scanning. An object of the present invention is to provide a magnetic resonance apparatus for diagnosis, which stops the scanning operation when the body movement of the patient resumes, and further reduces the burden imposed on the technician when controlling the scanning operation of the apparatus as much as possible.

[Structure of the Invention] (Means for Solving the Problem) In order to achieve the above object, the present invention performs a scanning operation for detecting magnetic resonance signals on a subject placed under magnetic resonance generation conditions. In a diagnostic magnetic resonance apparatus that performs a diagnosis on the subject based on a magnetic resonance signal detected by the scanning operation, a gate signal that detects body movement of the subject and synchronizes with this body movement. a body movement detection unit that outputs a signal, and a scan operation that is executed for a predetermined period of time when the body movement of the subject is stopped based on a gate signal output from the body movement detection unit, and The present invention is characterized by comprising a scan operation control section that stops the scan operation when the subject's body movement resumes during the scan operation.

(A1:) When collecting magnetic resonance signals by performing a scanning operation on a subject placed under magnetic resonance generation conditions, especially when the body movement of the subject becomes a problem, , are instructed to stop their body movements. When the subject stops his/her body movement according to this instruction, the output signal from the body movement detection section changes,
Using this as a trigger, a scanning operation that is executed over a predetermined period of time is started. Furthermore, when the subject's body movement resumes during this scanning operation, the output signal of the body movement detection section changes, and this is used as a trigger to stop the scanning operation. Note that these operations are automatically performed by the scan operation control section.

In this way, according to the present invention, it is possible to achieve the intended purpose.

(Embodiment) The configuration of an embodiment of the present invention will be described with reference to FIG. First, the magnet assembly includes a static magnetic field coil 1 that generates a static magnetic field, a gradient magnetic field coil 2 that generates a gradient magnetic field for imparting positional information at an induced site of a magnetic resonance (MR) signal, and transmits a rotating high-frequency excitation signal. It also includes a transmitting/receiving coil 3 for receiving the MR multiplied signal induced in the subject P.

The static magnetic field coil 1 includes a static magnetic field control system 4 including a static magnetic field power source, etc.
The X-axis gradient magnetic field power source 5, the Y-axis gradient magnetic field power source 6, and the Z-axis gradient magnetic field power source 7 are connected to each coil unit of the gradient magnetic field coil 2.

A transmitter 8 that generates various rotational high-frequency excitation signals and a receiver 9 that receives an MR multiplied signal from the subject P are connected in parallel to the transmitting and receiving coil 3. Further, a sequencer 10 is provided to perform pulse sequence control to be described later for each power source 5 to 7, transmitter 8, and receiver 9, and a computer system 11 is provided to control the entire system. Note that 12 is a display device on which a reconstructed image of the patient P is displayed. Further, the subject P is placed in a static magnetic field space generated by the static magnetic field coil 1 by means of the top plate 13 .

In order to detect body movements of the subject P, such as abdominal movements due to breathing, a body movement detector, such as an airbag 14, is wrapped around the relevant part. The internal pressure of this airbag fluctuates according to body movements, and a sensor 15 is provided to momentarily convert this internal pressure value into an electrical signal.

The output signal from this sensor 15 is fed to the computer system 11 via a preamplifier 16 and a comparator 17 as a gate signal synchronized with the stoppage of body movement. This computer system receives the gate signal and controls the operation of the sequencer 10 on and off as described below. Note that 18 is equipped with a speaker 19. This is a voice generating device that generates conversations as described below.

Next, the operation of the above configuration will be explained with further reference to FIGS. 2 to 4. Here, for example, the sequencer 10 will be described with reference to the timing chart shown in FIG. 2, assuming that the sequencer 10 implements a three-dimensional Fourier transform method. First, in the first slice of the first view, a slicing gradient magnetic field (Z
輔) is applied. Thereafter, first a first slicing gradient magnetic field is applied, then a first encoding gradient magnetic field is applied, and a read gradient magnetic field is applied. After these applications are completed, by applying the first slice gradient magnetic field along with the 180° pulse, an echo signal will be generated after a predetermined time has elapsed, and the echo signal will be collected by applying the read gradient magnetic field at this time. do.

From the second view to the Nth view, the encoding gradient magnetic field is applied to the second GE, the third GE,...the Nth GE.
Data collection for the first slice is performed by changing the magnetic field intensities to become smaller as shown in E.

Furthermore, data collection for each of the second slice to the Nth slice can be performed in the same manner as for the first slice. Furthermore, the slicing gradient magnetic field at the time of data acquisition for the second slice is smaller than that for the first slice, and similarly, it is smaller than that for the second slice. Apply the data and collect data for each slice.

During the data collection described above, the subject P holds his breath at the time when data collection for each slice is started, as shown in FIG. That is, the technician first operates the sound generating device 18 for the subject P, and then outputs the sound from the speaker 19.
Take a deep breath...and hold it. ” and hold the breath for an appropriate amount of time. This state is detected by the airbag 14, and the sensor 15 detects this state as shown in FIG.
After being converted into a body motion electrical signal as shown in FIG. 4(c), a gate signal is output via a preamplifier 16 and a comparator 17 in which the breathing hold period is at a high level and the breathing execution period is at a low level, as shown in FIG. 4(c). A signal is created.

When this gate signal is sent to the computer system 11, this system turns on the sequencer 10 in synchronization with the rise of the gate signal. When the sequencer 10 is turned on in this manner, the scanning operation by each component constituting the magnetic resonance apparatus is started according to the pulse sequence described earlier with reference to FIG. Data collection will be carried out. When this data collection is completed, the sound generator 18 outputs the speaker 19.
``Please start breathing and relax'' to prepare for data collection in the second slice.

After this, data collection from the second slice to the Nth slice can be performed by repeating the operation performed for the first slice described above. If the subject P starts breathing while collecting data for each slice, the gate signal changes from high to low, and the sequencer 10 is immediately turned off using this signal change as a trigger. The scanning operation by the device is stopped.

In this way, it is possible to prevent adverse effects on the collected data due to body movements of the subject P.

It should be noted that the present invention is not limited to the embodiments described above, and the design can be changed as appropriate without changing the gist of the invention. For example, instead of an air bag, a body motion detector based on other principles such as a thermistor or an optical cable can be used.

"Effects of the Invention" As described above, according to the diagnostic magnetic resonance apparatus of the present invention, the scanning operation of the apparatus starts in synchronization with the stoppage of body movement of the subject, and the patient is examined during the scanning operation of the apparatus. Since the scanning operation is stopped when the subject's body movements resume, data collection of the subject's body movements can be carried out extremely well, and the burden on the technician can be reduced as much as possible. can.

[Brief explanation of drawings]

FIG. 1 is a block diagram schematically showing the configuration of an embodiment of the present invention, FIG. 2 is a timing chart showing a pulse sequence by a sequencer in the same embodiment, and FIGS. 3 and 4 are respective diagrams of the same embodiment. Figures 5 and 6 for explaining the operation are diagrams for explaining the operation of the conventional example, respectively. 3... Transmission/reception coil, 4... Static magnetic field control system. 5...X-axis gradient magnetic field power supply, 6...Y-axis gradient magnetic field power supply. 7... Z-axis gradient magnetic field power supply, 8... Transmitter, 9...
receiver. 10...Sequencer, 11...Computer system. 14...Airbag, 15...Sensor. 16...Preamplifier, 17...Comparator. 18...Speech generator

Claims (2)

[Claims] (1) Performing a scanning operation for detecting magnetic resonance signals on a subject placed under magnetic resonance generation conditions, and diagnosing the subject based on the magnetic resonance signals detected by this scanning operation. A diagnostic magnetic resonance apparatus that detects body movements of the subject and outputs a gate signal synchronized with the body movements; Based on the scan operation, when the body movement of the subject is stopped, a scan operation to be executed for a predetermined period of time is started, and when the body movement of the subject is resumed during this scan operation, the scan operation is started. 1. A diagnostic magnetic resonance apparatus, comprising: a scan operation control section for stopping the scan operation. (2) The magnetic resonance apparatus for diagnosis according to claim 1, wherein the body movement detection section is mainly composed of an airbag.