JPS5855740A - Inspecting device using nuclear magnetic resonance - Google Patents

Abstract

PURPOSE:To obtain an immage having improved space resolving power with simple operation without prolonging signal processing time by performing data measuring samplings by plural data measuring samplings of different phases. CONSTITUTION:Coils 1, 4x, 4y, 5, 3 for generating static magnetic fields, inclined magnetic fields and high-frequency magnetic fields, a coil 3 for detecting the nuclear magnetic resonance signal from an object 2 to be examined, a calculator 9 which calculates the detection signal of the coil 3, and an outputting means 16 for the calculated results of the calculator are provided. The data measuring sampling by the coil 3 is performed by plural data measuring sampling point arrays of different phases, and a display image is formed by the combination thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention #i relates to an inspection device using nuclear magnetic resonance, and in particular uses nuclear magnetic resonance with improved spatial resolution by using a plurality of measurement point sequences with different sampling phases. -Regarding an inspection device.

Traditionally, OT and ultrasonic imaging devices have been widely used as methods for non-destructively inspecting the internal structure of the human body. Attempts to perform these tests have been successful, and it has become clear that it is difficult to obtain information that could not be obtained using XSO'R or ultrasound imaging devices.

An inspection device using magnetic resonance uses the nuclear magnetic resonance phenomenon to determine the density distribution of nuclear spins in a target object.

By nondestructively determining the relaxation time distribution, etc.,
This method constructs and outputs a cross-sectional image of a desired inspection part of a target object using a method similar to that of 〒.

To detect the density distribution and relaxation time distribution of nuclear spins in an inspection device using nuclear magnetic resonance, pulsed NMN is usually used.
law is used. That is, a high-frequency magnetic field is applied in a pulsed manner L1, thereby generating a free induction signal (F
D) is a method of observing. An example of the free guidance signal is shown in No. 111(A).

As is clear from the figure, the free-guided signal decreases exponentially, so its observation time! There is a problem that is determined by noise mixed in the detection system.

In addition, what is meant by the 7-Lier transform of the free induction signal is data that is projected in a certain direction of the nuclear spin distribution, depending on the sequence of the magnetic field until the free induction signal is generated. Or it is either one-line data of the nuclear spin distribution itself. 1st v! ! An example of the 7-lier transformed waveform of the free guided signal is shown in J@. In any case, it is the 7-lier transformed waveform of the free guided signal that determines the spatial resolution of the final image. The sampling interval Δf (see Figure 1) is the sampling interval Δf in the waveform obtained.

The sampling interval Δr and the observation time of the free induction signal mentioned above! Since there is a Δt −1/2T null HIA between the two, there is a problem in that the spatial resolution of the image depends on the detection system &/N.

However, to improve the spatial resolution of images,
There is a limit to adjusting the B/N of the detection system because it increases the data measurement time.

The purpose of the present invention is to provide an inspection device using nuclear magnetic resonance (hereinafter simply referred to as "inspection device") that is capable of obtaining images with improved spatial resolution through simple operations. It's there.

The above object of the present invention is to provide magnetic field generating means for a static magnetic field, a gradient magnetic field, and a high-frequency magnetic field, a signal detecting means for detecting a nuclear magnetic resonance signal from an examination object, a computer for calculating the detection signal, and a computer for calculating the detected signal. In an inspection apparatus having a calculation result output means, data measurement sampling by the signal detection means is performed using a plurality of data measurement sampler point sequences in phase 1IL1, and these are combined to form an image. This is achieved by using a new inspection device.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 shows the configuration of an inspection device that is an embodiment of the present invention. In the figure, a coil for generating an IFi static magnetic field, 2
The object to be inspected (in this case, the human body), the coil that generates the high-frequency magnetic field, the 4-piece,! , tj, respectively, in the X and Y directions (refer to the arrows on the right side of Figure 2 in the directions; however, in the X direction, the structure is shown vertically above the paper. The arrows in the figure indicate the direction of the current. The filter 41 that generates a gradient magnetic field in the Y direction is the coil 4 structure shown in Figure 3.
is rotated 90 degrees around 2@. Also,
5 is a coil that generates a gradient magnetic field in two directions, and each of the coils 4! , 4Y, and 5 are fill drive devices.

The high-frequency magnetic field generation coil 3a has the function of generating a high-frequency magnetic field and at the same time detecting the nuclear magnetic resonance signal generated from the target object 2, and uses a coil such as a rectangular shape, a solenoid shape, and a circular ring shape. . As the coil 6, a circular ring wired so that current flows in opposite directions is used.

The fill drive devices 6, 7.8 are operated by signals from the computer O. Further, the strength of the gradient magnetic field generated by the coils 4 and 6 can be changed by a command from the device 11 for detecting the size of the target object 2 or the operator of this device.

Next, the signal transmission system will be explained. The high-frequency magnetic field that excites the nuclear spins is generated by shaping and power-amplifying the high-frequency waves generated by the synthesizer 12 by the modulator 13, and by supplying current to the coil 3. Static magnetic field H
A target object 2 inserted into a coil 1 that generates 0
The high debris wave magnetic field and gradient magnetic field are applied to 1.
The signal from the target object 2 is received by the coil δ, passes through the amplifier 14, is orthogonally detected by the detector 1δ, and is input to the computer 9. After processing the signal, the computer 0 displays an image corresponding to the Hori spin distribution or the Hori spin relaxation time distribution on the OR1 display 16.
As shown in Fig. 4, a data point sequence with a smaller sampling interval is created from two data point sequences with different sampling phases, thereby obtaining an image with improved spatial resolution. In Figure 4, there are two data point sequences with a sampling phase of 180 Ilk (→ and (b)
, the data point sequence (6) with half the sprinter interval is
Data point sequence (→.

(1) is obtained by rearranging the data alternately.Here, reversing the sampling phase means inverting the static magnetic field by ΔH-t/r(Δf). How to do it.

(2) Two methods are possible: changing the frequency of the high-frequency magnetic field by Δt/2. Here, Δf is a sampling interval in the 7-lier transformed waveform of the free induction signal.

FIG. 6 shows an example of a method embodying the above-mentioned method (2), that is, the method of changing the static magnetic field 50! showed success.

The static magnetic field mentioned above■. A free induction signal of a subject 26 placed in the test object 26 is detected by a detection coil 20, subjected to MuD conversion by a MuD converter 21, subjected to 7-Lier transformation by a computer 22, and then stored in a memory 25. This data corresponds to the above-mentioned @4 diagram (&).

Next, according to a signal from the computer 22, the static magnetic field is changed to the above ΔH.
△H generation coil 19 and power supply 2 to change the
4 is closed to generate Δ■.
The data at this time is stored in memory 2 in the same sequence as before.
Store in 5. This data corresponds to the above-mentioned data.

Here, two data strings are extracted from the memory 25, arranged alternately to create data corresponding to the above-mentioned FIG. 4(a), and stored again in the memory 2δ.

FIG. 6 shows the configuration of an apparatus embodying the method (2) of changing the frequency of the high-frequency magnetic field.

In this device, a signal from a highly stable oscillator 28 is amplified by a pulse amplifier 27 and applied to a subject 26 by a high-frequency magnetic field applying coil 20, and the resulting free induction signal is detected by the coil 20. The converter 21 performs D conversion, and the computer 22 performs 7-D conversion, and then stores it in the memory 25.Next, based on the signal from the computer 22, the frequency of the oscillator 28 is changed to Δt/2. Shift and store the data at this time in the memory 25 in the same sequence as before 0 Then, take out the two data strings from the memo 92 and rearrange them alternately. Since only the parts directly related to the operation are shown, the overall configuration is %IIh''C
'Catfish See Figure 112 above.

In the apparatus shown in FIG. 6, the Δ■ generating coil 19 is used to change the static magnetic field (■), but in this case, the Δ■ generating coil 19 is not provided. , the static magnetic field generating coil l (see FIG. 2) may be adjusted.

As described above, according to the present invention, magnetic field generating means for a static magnetic field, a gradient magnetic field, and a high-frequency magnetic field, a signal detecting means for detecting a nuclear magnetic resonance signal from an examination object, and a computer for calculating the detected signal are provided. and an output means for outputting the calculation result by the computer, the data measurement sampling by the signal detection means is performed using a plurality of data measurement sampling point sequences having different phases, and these are combined to form an image. With simple operation,
This has the remarkable effect of making it possible to realize an inspection apparatus that can obtain images with improved spatial resolution without extending signal processing time.

[Brief explanation of the drawing]

Figure 1 shows the welfare freedom guidance signal, where @ shows an example of its Fourier transform wave carving, and Figure 2 shows *I of the embodiment device of the present invention.
rt, FIG. 3 is a diagram showing the gradient magnetic field generation filter, FIG. 4 is a diagram showing the operation of the device of this embodiment, and FIGS. FIG. 3 is a diagram showing the device configuration. 1: Coil for generating static magnetic field, 2: Object to be inspected, 3: Coil for generating high frequency magnetic field, cow! : X-direction gradient magnetic field generation coil, 4Y: Y-direction gradient magnetic field generation coil, 6: Z-direction gradient magnetic field generation coil, 6,7° 8: Coil drive device 19
: Computer, 10: Coil drive device for static magnetic field generation. Figure 1 Figure 4 Figure 3

Claims (1)

[Claims] A magnetic field generating means for a static magnetic field, a gradient magnetic field, and a high-frequency magnetic field, a signal detecting means for detecting a nuclear magnetic resonance signal from an examination object, a computer for calculating the detection signal, and a means for outputting the calculation result by the computer. An inspection apparatus using nuclear magnetic resonance characterized in that data measurement sampling by the signal detection means is performed by a plurality of data measurement sampling point sequences having different phases. Inspection equipment.