JP3516420B2 - Magnetic resonance imaging system - Google Patents

Magnetic resonance imaging system

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Publication number
JP3516420B2
JP3516420B2 JP16787795A JP16787795A JP3516420B2 JP 3516420 B2 JP3516420 B2 JP 3516420B2 JP 16787795 A JP16787795 A JP 16787795A JP 16787795 A JP16787795 A JP 16787795A JP 3516420 B2 JP3516420 B2 JP 3516420B2
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Prior art keywords
parameters
image quality
parameter
display
image
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JPH08336504A (en
Inventor
悦慈 上遠野
安彦 奈良
孝治 梶山
周子 森分
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株式会社日立メディコ
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Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic resonance imaging apparatus.
(Hereinafter, referred to as an MRI apparatus), particularly an MRI apparatus.
Characteristics of the image obtained by capturing the image with the
Related to display technology. [0002] An MRI apparatus utilizes a nuclear magnetic resonance phenomenon.
To image the inside of the subject. Imaging with MRI equipment
The image is obtained by placing the subject in a static magnetic field and applying RF
A pulse and a gradient magnetic field in two or three directions
NM generated within the subject by applying in accordance with the sequence
Detect the R signal and image it. Of the resulting image
Factors that determine the quality of image quality include spatial resolution and control.
Last, S / N ratio, spatial resolution,
Images with good trust and SN ratio are essential for medical diagnosis
You. In an MRI apparatus, prior to imaging,
It is necessary to set various parameters for imaging.
Here, the factors that determine the image quality are referred to as image quality parameters.
Parameters to be determined prior to imaging.
Data, but there is a deep relationship between them. photograph
The parameter includes, for example, F representing the size of the imaging visual field.
OV (short for Field of View), a pulse system that is performed repeatedly
Sequence repetition time (TR)
The time from excitation to the generation of an NMR echo signal,
That is, the echo time (TE), the thickness of the cross section of the object to be imaged.
Thickness, ie slice thickness, required for one image configuration
Number of NMR signals (Projection) and NM of the same encoding
There is the number of additions (NSA) of the R signal, and the like. [0004] Prior to photographing, the operator needs to take the above-mentioned photographing parameters.
The meter is input.
Set image quality while imagining image quality based on conventional imaging experience
That is the current situation. [0005] Therefore, the imaging experience
To set shooting parameters for poor operators
Spends considerable time reducing diagnostic efficiency
There was a problem. Also, as described above, the image quality parameter
Greatly depends on the shooting parameters.
To change the image quality parameter
How the data changes can only be done by a very skilled person.
If it is difficult to understand immediately,
First notice of mistake in setting shooting parameters
In many cases, improvement was desired. Accordingly, the present invention has been made in view of the above problems.
The first object of the present invention is to provide an MRI apparatus.
Of the image quality parameters and shooting parameters
The relationship is displayed on the display device, and the shooting parameter settings are
Make it easier by referring to the display of
It is in. A second object of the present invention is to provide an MRI apparatus.
, When the shooting parameters are changed,
How the image quality parameter changes depending on
To be able to inform the operator prior to imaging.
You. [0007] The above-mentioned first object is achieved.
Therefore, the present invention provides a photographing parameter necessary for photographing an MR image.
Data and an image quality parameter indicating the image quality characteristics of the MR image.
Storage means for storing in a fixed format, and this storage means
Display means for displaying the content read from the
The image quality parameter displayed on the display means of
At least one of the shooting parameters
Input means for selectively inputting data, and
Therefore, parameters related to the specified parameters are found.
So that only relevant parameters can be identified
Identification information adding means for adding identification information to the output of the storage means
A step is added to the MRI apparatus. The present invention achieves the second object.
Setting and setting of parameter values required for MR image capture
A photographing parameter inputting means for inputting a change of a fixed value;
An image quality parameter indicating the image capturing parameter values and the image quality characteristics of the MR image.
Storage means for storing parameters in a predetermined format
And a display for displaying the contents read from the storage means.
Play means and the relationship between shooting parameters and image quality parameters
Provided with calculation software for the
Image quality parameters for the meter and shooting parameters after the change
The image quality parameters for the
Image quality parameters for the current shooting parameters
The changed state is compared, and the format in the storage means is determined.
Computing means for outputting a signal for writing the change state to
This is added to the MRI apparatus. According to the first aspect of the present invention, the storage means is provided.
Image quality parameters and shooting parameters stored in a fixed format
The meter is read out and displayed on the display means.
While referring to this display screen, the image quality
At least one of parameters or imaging parameters
When the input is selectively specified,
The separate information adding means is a parameter associated with the designated parameter.
Parameters and determine only relevant parameters
Contents stored in storage means so that they can be identified from parameters
, Identification information, for example, a luminance difference or a hue difference. this
The contents of the storage means provided with the identification information are read out and
Displayed on the display means. This allows the operator to
The relationship between parameters can be easily grasped. According to the second aspect of the present invention, the storage means
Image quality parameters and shooting parameters are
And stored from the camera parameter input means.
When the parameters are set, the format is set.
Is displayed on the display means
You. Here, the shooting parameter is set by the shooting parameter input means.
When the meter is changed and input, the calculation means
Image quality parameters for the shooting parameters before change
And image quality parameters for the changed shooting parameters
In addition, the change state is obtained, and the
Then, a signal for writing the change state is output. others
Therefore, from the storage unit, the changed state is written
Format display signal is output,
Displayed on the column. This allows the operator to set the shooting parameters
Before viewing the captured image.
Can be Embodiments of the present invention will be described below with reference to the drawings.
You. FIG. 6 is a schematic diagram of the entire MRI apparatus embodying the present invention.
It is a block diagram showing composition. RMI device shown in FIG.
Are roughly divided into a central processing unit (CPU) 1 and a sequencer.
2, a transmission system 3, a static magnetic field generating magnet 4, and a gradient magnetic field generating device.
Raw system 5, receiving system 6, signal processing / display system 7,
8. The CPU 1 has a keyboard 8 of the console 8.
Measurement pulse sequence input from an input device such as
Sequencer 2, transmission system 3, tilt according to shooting parameters
Controls gradient magnetic field generation system 5, reception system 6, signal processing / display system 7
The sequencer 2 is controlled by the CPU 1
Based on the command, the pulse sequence and shooting parameters
Measurement data for obtaining a tomographic image of the subject 100 according to the data
Sends various commands necessary for data collection to transmission system 3 and generation of gradient magnetic field
These are output to the system 5 and the receiving system 6. The transmitting system 3 includes a synthesizer 31 and a modulator.
32, a high frequency amplifier 33, and an electromagnetic wave (R
F pulse) and an irradiation coil 34 for irradiating
High frequency output by the synthesizer 31 in response to a command from the
The wave pulse is amplitude-modulated by the modulator 32.
The amplified high-frequency pulse is amplified by the high-frequency amplifier 33 and irradiated.
To the subject 100 from the irradiation coil 34.
It is designed to emit magnetic waves. The static magnetic field generating magnet 4 accommodates the subject 100
That generate a uniform static magnetic field in a predetermined direction in a moving space
Of superconducting type, normal conducting type or permanent magnet type
Either type of magnet can be used. And gradient magnetic
The field generating system 5 includes a gradient magnetic field power supply 51 and this gradient magnetic field power supply.
51 and three sets of gradient coils 52 connected to
The gradient magnetic field power supply 51
A gradient magnetic field is generated by supplying a current from the
As a result, the static magnetic field and the gradient
It generates a magnetic field. In addition, three sets of gradient magnetic field coils
The slice direction, the phase encode direction, and the frequency
It is used corresponding to the code (read) direction. The receiving system 6 includes an NM generated from the subject 100.
A receiving coil 61 for receiving the R signal;
An amplifier for amplifying the output signal;
Signal is orthogonally detected by the reference signal from the synthesizer 31.
Quadrature detector 63 and the output of quadrature detector 63
An A / D converter 64 for A / D converting the force signal,
Fourier processing of the detected NMR signal by the signal processing / display system 7
The image is converted and output so that the image can be reconstructed. The signal processing / display system 7 is a part of the CPU 1.
And external storage devices such as a magnetic disk 71 and an optical disk 72.
And a display 73 such as a CRT.
The CPU 1 calculates and processes the signal from the receiving system 6
Reconstruction processing and display the result on the display 73
At the same time, it is stored in the external storage device 70.
The console 8 includes a keyboard 81 and a mouse 82
And an input device consisting of various pushbutton switches and a display
I have. Next, the image quality parameter and the photographing parameter
The relationship will be described. First of all, used in MRI equipment
Spin Eco
The pulse sequence of the method (SE method) will be described with reference to FIG.
You. The SE method is applied to a subject 100 placed in a static magnetic field.
In the state where the slice-direction gradient magnetic field 201 is applied,
Frequency and band according to chair position and slice thickness (Thickness)
A high-frequency pulse (RF pulse) 101 in the region is applied. R
The F pulse 101 is called a 90 ° RF pulse.
Nuclear spin in the subject is measured by RF pulse
It is an amount that falls by 90 ° to the direction. This allows
Only nuclear spins in the set slice of sample 100 are selected.
It is selectively excited. Following this slice selection, the selection
Align the phase of the excited nuclear spins in the slice direction.
For this purpose, a slice-direction gradient magnetic field 202 is applied. This
The applied amount of the gradient magnetic field 202 is the applied amount of the gradient magnetic field 201a.
It is assumed to be equal to. Next, tilt at right angles to the slice direction.
Gradient magnetic fields 301 and 401 are applied. The gradient magnetic field 301
Tilt applied in one of two orthogonal directions in the slice plane
At the end of the application to the nuclear spin in that direction in the magnetic field
Since it is applied for the purpose of giving a phase difference,
This is called a gradient magnetic field. This phase encoding gradient magnetic field 301
Indicates a stepped intensity according to the repetition of the pulse sequence.
And applied. This number of steps is
It corresponds to the number of pixels in the encoding direction. That is, the phase
To obtain an image of 256 pixels in the code direction, 256 pixels
It is necessary to perform step phase encoding. Meanwhile, inclined
The magnetic field 401 is applied in the phase encode direction in the slice plane.
A gradient magnetic field applied in a direction perpendicular to the direction
Phase shift (Dephasi
ng). This gradient magnetic field 40
Since the direction in which 1 is applied is the read direction, the read direction
To identify the gradient magnetic field or readout signal by frequency
Also called a frequency encoding gradient magnetic field. Following the application of the gradient magnetic field in these two directions,
To apply the slice-direction gradient magnetic field 203 again.
At the same time, an RF pulse 102 is applied. RF pulse 10
2 further reduces nuclear spins in the 90 ° excited slices by 18
Excitation (inversion) by 0 °. And this 180 ゜ RF pal
Following the scan 102, the readout gradient magnetic field 402 is marked.
Add. The readout gradient magnetic field 402 is a normal gradient magnetic field.
Double the amount of the field 401 is applied, and the echo signal is
Is the largest. From the application of the RF pulse 101 to the gradient magnetic field 4
The elapsed time up to the center of 02 is called an echo time TE.
6 together with the application of the readout gradient magnetic field 402.
In the receiving system shown, the NMR signal is detected by the receiving coil 61
Then, the A / D converter 64 samples the signal.
The number of pixels in the image reading direction is a signal from the A / D converter.
Corresponds to the number of samplings. After measuring the echo signal, 90 ° RF
Pulse 103 is applied together with slice direction gradient magnetic field 204
I do. Thus, the second start of the pulse sequence
It becomes. 90 ° RF pulse 101 and 103 application time
The interval is called a pulse sequence repetition time TR. the above
To obtain one image by the SE method, use the pulse sequence described above.
Run multiple times. The number of times to execute
The number of pixels in the phase encoding direction and the S / N ratio
Involved. Here, the SN ratio is related to the number of times.
Signal obtained by pulse sequence of same phase encoding
Can be improved by averaging
According to Therefore, as the addition is performed twice and the addition is performed three times, SN
Ratio is improved, but at the same time
The number of rows also increases in proportion. The average number of times is NSA
If the number of steps of the phase encoding is N, one
The measurement time (Time) for obtaining an image is as follows: Time = TR · N · NSA (1) Next, the image quality parameter and the photographing parameter of the present invention will be described.
An apparatus configuration for displaying the relationship between the meters will be described with reference to FIG.
You. In FIG. 1, reference numeral 11 denotes a measurement data memory, and FIG.
Output signal of the A / D converter 64, ie, digital
For sequentially storing the converted NMR signals, 12 is a microphone
B Processor unit (hereinafter referred to as MPU)
With software stored in the built-in memory.
Fourier transform for the contents stored in the measurement data memory 11
Also, calculating image quality parameters and shooting parameters
Reference numeral 13 denotes an image memory, which is an image output from the MPU 12.
For storing image data, 14 is a graphic memory
To the image output from the image memory 13
And shooting conditions, etc., are displayed in characters and numbers and superimposed.
15 is an image synthesizing circuit.
For synthesizing the contents of the graphic memory 14 with an image, 7
Reference numeral 3 denotes a display comprising the CRT shown in FIG.
The output of the circuit 15 is converted into an analog signal by the D / A converter 74.
Input and display images. Reference numeral 8 denotes a console shown in FIG.
In addition to the keyboard 81 and the mouse 82, the illustration of the rule 8 is omitted.
While equipped with various switches and indicators that were
The screen displayed on the display 73 is obtained by imaging the subject.
Images or image quality and shooting parameters
Display switching switch to switch the screen to
The switch 83 is provided. Reference numeral 84 denotes a parameter display memory, which is preferably
Or a plurality of frame memories.
The relationship between data and shooting parameters is recorded in a predetermined format.
The contents are read by external input.
Can be read out and rewritten
I have. The contents of the parameter display memory 84 are
In order to selectively supply and display on the display 73,
A changeover switch 85 is provided. Note that the measurement data
Memory 11, MPU 12, image memory 13, graphics
The memory 14 is a component of the CPU 1 in FIG. Next, the data is stored in the parameter display memory 84.
The relationship between the image quality parameter and the shooting parameter
FIG. 2 shows the display format. In FIG. 2, 81
0 is an image quality parameter, and the SN ratio (S / N) 811,
Trust (Contrast) 812, spatial resolution (Resolution)
813. In the present embodiment, the spatial
Time resolution with respect to resolution
I can't say, but the shooting time is deeply related to the shooting parameters
(Time) 814 is arranged in the same row as the image quality parameter.
You. Alphabet for each image quality parameter and shooting time
And the circular display portions 811a to 811a
814a. On the right side of the display area of the image quality parameter 810,
Is provided with a display area for shooting parameters 820.
You. The imaging parameter 820 is a field of view (FOV) 82
1, pulse sequence repetition time (TR) 822
Koh time (TE) 823, slice thickness (Thickness) 8
24, the number of projections (Projection) 825, signal
Alphabet sentence consisting of additive numbers (NSA) 826
Display and circular display units 821a to 826a on the left side
And display units 821b to 826b by numbers.
The above display format is the parameter display menu shown in FIG.
It is stored in the memory 84. Next, the image quality parameter 810 and the shooting parameters
The display related to the data 820 will be described. The operator
Turn on the power of the MRI system and switch the display of the console 8
When the switch 83 is turned on, the imaging region and the pulse
The type of sequence is input from the keyboard 81. Do
In the input imaging region and pulse sequence used
The table shown in FIG. 2 including standard shooting parameters 830
The display format is displayed on the display 73. display
Standard parameters are sequenced via MPU12.
If the measurement is started in this state, it will be displayed.
Images of the selected shooting parameters
You. Prior to photographing, the operator gives priority to the SN ratio.
It is assumed that a photographed image is taken. In this case,
The author moves the cursor with the mouse 82 on the S / N of the display screen.
Take it to 811 and click. Then, in FIG.
As shown, the S / N 811 frame has a brightness difference with respect to other portions.
Or 811a to 8
The inside of all the left circles of 16a is the same as other parts
It is displayed as if the lamp was lit with a difference or hue.
In this display, a signal from the mouse 82 is input to the MPU 12
Processing by software embedded in the MPU 12
The output is stored in the parameter display memory.
This is performed by inputting the information to the key 84. As a result, the SN ratio becomes
(FOV) 821, (TR) 822, (TE) 823, (T
hickness) 824, (Projection) 825 and (NS
A) It is related to all parameters of 826
Recognized by the operator. Next, taking priority to the contrast of the image,
Assume that the operator wishes to shadow. At this time, the operator
(Contrast) 812 is selected using the mouse 82. You
Then, the frame of (Contrast) 812 as shown in FIG.
And the circles on the left of (TR) 822 and (TE) 823
The other parts are displayed with a luminance difference or a hue. This
As a result, the contrast of the image is repeated in the pulse sequence.
It is necessary for the operator to relate the return time and the echo time.
Understand. Further, the resolution of the image depends on
If the operator wants to know whether or not
Use to select (Resolution) 813. Then, FIG. 3 (c)
As shown in the figure, (Resolution) 813 and (FO)
V) Luminance difference between circles to the left of 821 and (Projection) 825
Alternatively, a hue is given and displayed. This allows you to
Resolution is related to FOV and number of projections
You can see that. In the above, the image quality parameter is specified, and
Displays the relevant shooting parameters and recognizes them by the operator
Although it is possible to do so,
Display which image quality parameters are
This will increase the convenience for the operator. In other words,
Parameters can be set arbitrarily by the operator within the specifications of the device
However, the operator can determine which shooting parameters are
It is difficult to judge instantaneously whether or not it is related.
The embodiment described below takes this measure into consideration.
You. The format shown in FIG.
Until it is displayed in step 3, the procedure proceeds in the same manner as in the previous embodiment.
Run. Here, as an example, the operator is asked to enter the mark shown in FIG.
(FOV) 8 of the standard shooting parameter value group 830
If the user tries to reset 21, the shooting parameter F
OV indicates which of the image quality parameters to shoot
FIG. 4 shows what can be known.
You. The operator looks at the display screen shown in FIG.
Of the shooting parameter (FOV) 821 using the
Select. Output signal of mouse 82 is for parameter display
Input to the memory 84 and input to the MPU 12.
Then, the MPU 12 makes the built-in software based on the input signal.
Image quality related to FOV of shooting parameters from software
Find the parameters, (S / N) 811 and (Resolution)
In the circle to the left of 813, that is, 811a and 813a
Alternatively, a signal for distinguishing from other parts by the hue is output. Ma
Similarly, the luminance difference is also set within the frame of (FOV) 821.
Alternatively, a hue is given. As a result, the display 73
A format as shown in FIG. 4 is displayed on the screen. The above example is based on the FOV shooting parameters.
Display of image quality parameters was explained, but other shooting parameters
The same display is possible for data, and for (TR)
Is not (S / N), (Contrast) and image quality parameters
Is (Time) and (S / N) and (Cont) for (TE).
rast), (S / N) for (Thickness), and (Rr
ojection) for (S / N) and (Resolution)
(Time), (S / N) and (Time) for (NSA)
To be displayed in association with each other. These associations
Can be performed by software embedded in MPU12.
it can. As described above, the image quality parameter and the photographing parameter
Can be displayed in a convenient way for the operator.
It will be clear that the device has been improved over the conventional device. But
If the shooting parameters are changed with respect to the set values,
What the quality will be is unknown from the above example. So
Here, what is the image quality when changing the shooting parameters?
Hereinafter, an embodiment for displaying whether it is changed to will be described. Parameter display format in this embodiment
Is shown in FIG. In the upper part of FIG.
Display section 810 and a bar graph display section 8 for qualitatively indicating the height thereof.
Indicates the image quality parameter display format consisting of 40
In the lower part, a photographing parameter table similar to that of the above embodiment is provided.
To the display format 820, 830
Shooting parameter display format with a rough display unit 850
Is shown. To display these formats
The configuration of the device is the same as that of the above-described embodiment.
Data display memory 84, MPU 12 and software
Components. Next, the operation and display operation of this embodiment will be described.
You. The operator turns on the power of the MRI apparatus and
8 is turned on and the photographing unit is turned on.
Input the position, type of pulse sequence, etc. from the keyboard 81.
Power. Then, a parameter is displayed on the display 73.
The format shown in FIG.
Is shown. At this time, set each of the shooting parameters.
Standard for defined imaging site and pulse sequence type
The numerical value is displayed. These displayed shooting parameters
Not only is displayed, but the actual shooting can be started
Is set to the device as follows. Each bar graph (81) in the image quality parameter display section
1c to 814c) has a dividing line 815 at the center.
You. The dividing line 815 is used to set the above-mentioned initially set photographing parameter.
Indicates the level of image quality by the meter. Therefore, the initial setting
For certain shooting parameters, the bar graphs
This is indicated by the dashed line. This display mode includes a partition line 81
5 is displayed with a certain thickness,
A bar-shaped object having a certain length may be displayed. On the other hand, a bar graph 8 in the photographing parameter display section
Reference numeral 50 denotes each imaging parameter due to a limitation from the specifications of the MRI apparatus.
Indicates the settable range of the meter, for example, (FOV) 8
The FOV is 5 for 50 and 300 in the bar graph 821c of 21.
Set within the range of 0 × 50 (mm) to 300 × 300 (mm).
The initial setting value 250 is within the range.
Is shown. Next, in order to change the image quality parameter,
A case when the photographing parameters are operated will be described. Operation
Let's get an image with better spatial resolution than the default value
First, operate the mouse 82 of the console 8
And select and specify (Resolution) 813 on the screen. You
Then, as shown in FIG.
(FOV) 821 and (Projection) 825
Displayed with the difference or hue given to other parts
You. The spatial resolution R is the phase resolution R p When,
Frequency direction resolution R f And the slice direction resolution R s And in
In the formula, R = R p ・ R f ・ R s ... (2), and these are R p = Projection / FOV ... (3) R f = Sample / FOV ... (4) R s = K / Thickness (5) Here, Sample can be expressed as a sampling number. Therefore, the initial setting values of the photographing parameters
On the other hand, the MPU 12 performs the above (2), (3), (4),
Calculates the spatial resolution R using the equation and holds the value.
You. From this state, the operator changes the spatial resolution,
(FOV), (Projection), and (Thickness) data to the right
While referring to the settable range of
Input is performed using the board 81 and the mouse 82. As an example
The (FOV) is 200 (mm) and the (Projection) is 25
It is assumed that 3 (mm) is input to (Thickness) with 6 being kept.
Assuming that the number of samples is the
You. When these settings are updated on the display screen,
The data is input to the CPU 1. And MP of CPU1
In U12, empty based on the above formulas (2) to (5).
The calculation of the inter-resolution R is performed. In this case, the spatial resolution R is
(250/200) Two × (5/3) better than the initial setting
Up. The MPU 12 compares this calculation result with the held value.
The MPU 12 compares the parameter display memory 84
Bar graph 813c against (Resolution) is drawn to the right
Rewrite it to be stretched and displayed. This rewritten
The contents of the stored parameter display memory 84 are read out and
When displayed on the spray 73, it becomes as shown in FIG. Next, the case of contrast will be described. Ko
Trust is determined by TR and T as described in the previous embodiment.
Related to E. This is explained from the following. I
The image contrast C is C∝ [S 1 -S Two ] / [S 1 + S Two ] (6) where S 1 : Signal strength S of tissue 1 Two : Signal intensity of the tissue 2 []: Represented by an absolute value symbol. And again, S 1 ∝Sd 1 ・ P X ・ P Y ・ P Z … (7) S Two ∝Sd Two ・ P X ・ P Y ・ P Z (8) where Sd 1 : Signal Sd of tissue 1 by pulse sequence Two : Signal P of tissue 2 by pulse sequence X : Pixel size P in X direction Y : Pixel size P in Y direction Z : Pixel size in the Z direction. And furthermore, the pulse sequence
Is the SE method, Sd 1 And Sd Two Can be expressed as
You. Sd 1 ∝ρ 1 ・ Exp (-TE / T twenty one ) ・ [1-exp (-TR / T 11 )]… (9) Sd Two ∝ρ Two ・ Exp (-TE / T twenty two ) ・ [1-exp (-TR / T 12 )] ... (10) where ρ 1 : Proton density ρ of tissue 1 Two : Proton density T of tissue 2 11 : Vertical relaxation time T of organization 1 12 : Vertical relaxation time T of organization 2 twenty one : Lateral relaxation time T of organization 1 twenty two : Transverse relaxation time of tissue 2 Therefore, the proton density ρ of the tissue and the set
Weave longitudinal relaxation time T 1 And the lateral relaxation time T of the organization Two The biological
Measure in advance for representative tissues, such as muscle and fat
And memorize it to correspond to the input TR and TE.
Sd 1 And Sd Two But then S 1 And S Two And estimated
The contrast changes TR and TE according to equation (6).
MPU12 calculates whether or not it will rise
obtain. The MPU 12 generates a parameter table based on the result.
The bar graph in the display memory 84 is rewritten, and the rewritten
The displayed contents are displayed on the display 73. Further, in the case of the SN ratio, the display is as follows.
Is done. The S / N ratio is, as described in the above-described embodiment,
(FOV), (TR), (TE), (Thickness), (Projecti
on) and (NSA). This is
Can be explained as follows. That is, first, the SN ratio is
Assuming that the degree is S, the SN ratio ∝S (11), and the signal strength S is S∝Sd · P X ・ P Y ・ P Z (12) where, Sd: tissue signal P by pulse sequence X : Pixel size P in X direction Y : Pixel size P in Y direction Z : Represented by the pixel size in the Z direction. The pixel size in the X, Y, and Z directions is assumed to be X
Direction is slice direction, Y direction is phase encode direction, Z direction
If the direction is the frequency encoding direction, P X ∝Thickness… (13) P Y ∝FOV / Projection… (14) P Z ∝FOV / Sample (15) When the pulse sequence is the SE method,
Sd∝ρ · exp (−TE / T) as shown in the equations (9) and (10). Two ) ・ [1-exp (-TR / T 1 )] (16) where, ρ: proton density T 1 : Vertical relaxation time T Two : Transverse relaxation time TR: repetition time TE: echo time. Further, as described above, the SN ratio∝NSA (17). Therefore, the photographing parameters of the initial set values
Only desired shooting parameters for SN ratio for group
Whether or not the SN ratio when the input is changed becomes higher depends on the above.
Parameters changed from (11) to (17) are related
It can be determined using a calculation formula. This operation and
The display resolution and contrast
This can be performed in the same manner as described above. The parameter display format shown in FIG.
The number of slices 827 not shown in the example shown in FIG.
Including shooting time [Time] 814
You. Is this shooting time longer or shorter depending on the shooting parameters?
It becomes cloudy. This is clear from equation (1). This implementation
In the example, it is a shooting parameter that determines the image quality,
When you change the shooting parameters related to
According to the equation (1), the shooting time is longer than before the change.
MPU12 calculates whether it will be shorter or shorter and displays it as a bar graph
As shown. This calculation and display method are also described above.
Obviously it can be done in the same way as the method
Therefore, detailed description is omitted. The present invention has been described based on the embodiments.
However, the present invention can be variously modified without departing from the gist.
It is. For example, in the embodiment shown in FIG.
The change status of the image quality parameter for the shooting parameter
Not a qualitative thing like a graph, a numerical display, for example
It can also be done quantitatively like percentage display
It is. Also, the imaging parameters for one subject many times
When shooting with different settings,
Changes the image quality parameters for shooting parameters
Displayed only for the specified time, and after the specified time, the changed parameter
The image quality parameter bar graph
Displayed on the partition line to prepare for the next change of shooting parameters
You may do it. In this embodiment, the shooting parameters are
FOV, TR, TE, slice thickness, projection
Although the explanation has been given with reference to the number of
If the data is related to image quality other than these,
It is also possible to carry out additionally. In addition, image quality parameters
As a calculation formula to estimate the relationship between
Can be applied to anything other than those shown in (2) to (17).
It is possible. As described above, according to the present invention, the image quality
Parameters and shooting parameters in a predetermined format.
Display on the display and select and specify a certain parameter
And the parameters related to the specified parameter
The parameter settings are displayed so that they can be identified.
It is easily possible. Also, image quality parameters and shooting parameters
Data on the display in a predetermined format
Also, if you change the shooting parameters,
Display how the image quality parameter has changed
Therefore, the operator does not need to look at the actual image
The change in image quality of images captured from
Become.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a circuit configuration relating to parameter display according to an embodiment of the present invention. FIG. 2 is a diagram showing a display format of a first embodiment of a parameter display method according to the present invention. FIG. 3 is an exemplary view showing a screen during operation of the display format shown in FIG. 2; FIG. 4 is an exemplary view showing a screen at the time of operation in a mode opposite to the display shown in FIG. 3; FIG. 5 is a diagram showing a display format and a screen during operation according to a second embodiment of the parameter display method of the present invention. FIG. 6 is a block diagram showing a schematic configuration of an MRI apparatus. FIG. 7 is an SE pulse sequence diagram used in the MRI apparatus. [Description of Signs] 8 Console 12 MPU 73 Display 81 Keyboard 82 Mouse 83 Display switch 84 Parameter display memory

Continuation of the front page (56) References JP-A-3-37044 (JP, A) JP-A-6-90926 (JP, A) JP-A-5-176911 (JP, A) (58) Fields studied (Int) .Cl. 7 , DB name) A61B 5/055

Claims (1)

  1. (57) [Claim 1] Storage means for storing, in a predetermined format, imaging parameters necessary for imaging of an MR image and image quality parameters indicating image quality characteristics of the MR image, and reading from the storage means. Display means for displaying the displayed contents, input means for selectively designating and inputting at least one of image quality parameters or photographing parameters displayed on the display means, and parameters designated by the input means. A magnetic resonance imaging apparatus comprising: identification information providing means for obtaining related parameters and adding identification information to the contents of the storage means so that only the related parameters can be identified. 2. An imaging parameter input means for inputting setting of parameter values required for imaging of an MR image and a change of the set values, and an image quality parameter indicating an image quality characteristic of the MR image in a predetermined format. Storage means for storing, display means for displaying contents read out from the storage means, and software for calculating the relationship between the shooting parameters and the image quality parameters, wherein the image quality parameters for the set shooting parameters and the changed shooting parameters And calculating means for determining the image quality parameter with respect to the image quality parameter and comparing the image quality parameter with the changed image quality parameter as compared with the setting, and outputting a signal for writing the changed state in a format in the storage means. A magnetic resonance imaging apparatus comprising:
JP16787795A 1995-06-12 1995-06-12 Magnetic resonance imaging system Expired - Fee Related JP3516420B2 (en)

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DE102004026616B4 (en) * 2004-06-01 2007-09-20 Siemens Ag Method for measuring an examination area with a magnetic resonance apparatus
JP4822397B2 (en) * 2005-04-05 2011-11-24 株式会社日立メディコ Magnetic resonance imaging device
JP4822435B2 (en) * 2006-10-13 2011-11-24 株式会社日立メディコ Magnetic resonance imaging apparatus having imaging parameter setting support function
JP5294230B2 (en) * 2007-02-23 2013-09-18 独立行政法人産業技術総合研究所 Identification and quantification method of marbling and non-invasive measuring apparatus of marbling
JP5127310B2 (en) * 2007-06-11 2013-01-23 株式会社日立メディコ Magnetic resonance imaging system
JP5280116B2 (en) * 2008-06-26 2013-09-04 ジーイー・メディカル・システムズ・グローバル・テクノロジー・カンパニー・エルエルシー Scan condition determining apparatus, medical system, and scan condition determining method
JP5498339B2 (en) * 2009-11-05 2014-05-21 株式会社東芝 Magnetic resonance imaging system
JP5635254B2 (en) * 2009-11-09 2014-12-03 ジーイー・メディカル・システムズ・グローバル・テクノロジー・カンパニー・エルエルシー Scan condition setting device and medical device
US10132899B2 (en) 2012-10-10 2018-11-20 Hitachi, Ltd. Magnetic resonance imaging apparatus with voxel size control based on imaging parameters and magnetic susceptibility
JP6063363B2 (en) * 2013-09-11 2017-01-18 株式会社日立製作所 Magnetic resonance imaging apparatus, imaging parameter determination method, and imaging parameter determination program
DE102014210460B4 (en) 2014-06-03 2016-02-04 Siemens Aktiengesellschaft Evaluation of automatically set parameters of an MR system
DE102014211586B3 (en) 2014-06-17 2015-10-22 Siemens Aktiengesellschaft Use dependency records when deploying and / or reviewing MR measurement sequences
KR101788742B1 (en) * 2015-12-28 2017-10-20 삼성전자주식회사 Device and method for outputting parameter information for shooting medical images

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