JP2003144416A - Magnetic resonance imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set a labeled region into a suitable position allowing labeled bloodstream to be imaged at a portion of interest, with simple operation in a magnetic resonance imaging device. SOLUTION: This magnetic resonance imaging device magnetically labels a photographed object including a moving body in the labeled region in a photographed region by impressing specific high frequency pulse during the impression of the inclined magnetic field according to the prescribed pulse sequence, and acquires an image with the photographed object labeled by carrying out operation for collecting signals from the photographed region after a waiting time from the high frequency pulse. The device is provided with an MRA expert system 120 for displaying a mark for showing the labeled region, on a reference image; an input apparatus 113 for carrying out operation for moving the mark for showing the labeled region, into an optional position and deforming it into optional shape; and a computer 106 for editing pulse sequence according to the position and shape of the inputted labeled region.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic resonance imaging apparatus having an MR angiography (MRA) function.

[0002]

2. Description of the Related Art In magnetic resonance imaging, nuclear spins of a subject placed in a static magnetic field are excited by a high frequency signal of Larmor frequency, and FID (free induction decay) signal and echo signal generated by the excitation. Is a method of obtaining an image from.

One of the categories of magnetic resonance imaging is MR angiography for imaging the dynamics of blood. Furthermore, as one form of MR angiography, there is a method of locally labeling spins with an inversion pulse (high-frequency inversion pulse) to cause signal loss.

For example, a portion (label area) to be presaturated by the inversion pulse is set together with a time interval from the inversion pulse to the excitation pulse of the main scan, and a signal change (reduction of signal) is caused by the influence of the presaturation. A flow imaging method (bolus tracking method, Edelman, et.a.
l., Radiology, Vol.171,551-556,1989).

FIG. 9 shows a pulse sequence by this method, and FIG. 10 shows a conventional label area setting screen. First, the inversion pulse 1 is applied. At this time,
The slice selection gradient magnetic field 2 is applied so that the region (label region) assumed to be the source of inflow to the region of interest ROI is selectively inverted-excited, and the offset frequency corresponding to the position of the label region is applied. 3 is added to the inversion pulse 1. The label area can be set in any direction by applying it in the direction shown by the dotted line in FIG. 9, for example. For these setting methods, see Ma
tt Bernstein et.al., JMRI, Vol. 4, 105-108, 1994, etc.

After the waiting time (reversal time) TI [s] from the inversion pulse 1, the imaging section is excited by the excitation pulse 4. After applying the phase encode gradient magnetic field 5, the echo signal 6 is collected after the echo time TE. By repeating this series of operations by the number of encoding steps required for image reconstruction, one image capturing is completed.

Assuming that the echo time TE is sufficiently shorter than the inversion time TI, the blood flow presaturated in the label area 7 when the blood flow moves in a certain direction at the average velocity v [m / s] is It is captured at a position that has moved by approximately v × TI [m]. As a result, it is possible to observe the movement of the shooting target during shooting.

When this method is used for diagnosis, the setting of the location of the label area and the setting of the inversion time TI are the most important photographing parameters, but they are not intuitive to the operator and are difficult to use. there were.

For example, when it is desired to observe the dynamics of the blood flow in the vicinity of the region of interest ROI, the region of interest R is just when the presaturated blood flow applies the excitation pulse 4.
It is necessary to set the label area at a position upstream by an appropriate distance with respect to the ROI so that the OI is reached. This distance is determined depending on the blood flow velocity v and the inversion time TI. Therefore, in order to collect a target image, it is necessary to shoot while changing the inversion time TI variously, or to repeat shooting while moving the label area, which is very inconvenient. In particular, the range that can be set as the reversal time TI is limited due to circumstances such as the T1 value of the object to be photographed, and it may be difficult to set it.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to set a label region in a magnetic resonance imaging apparatus at a suitable position where a labeled blood flow can be visualized in a region of interest by a simple operation. Alternatively, it is to be able to set such a suitable inversion time by a simple operation.

[0011]

According to the present invention, an imaging including a moving object in a label area in an imaging area is performed by applying a specific high frequency pulse during application of a gradient magnetic field under a predetermined pulse sequence. A magnetic resonance imaging apparatus for labeling an object by a magnetic resonance phenomenon and, after waiting from the high frequency pulse, performing an operation for collecting a signal from the imaging region to obtain an image labeled with the imaging object. In, the mark representing the label area, means for displaying on the reference image, an input means for moving the mark representing the label area to an arbitrary position and deforming into an arbitrary shape, and the input label Means for editing the pulse sequence according to the position and shape of the region.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION A magnetic resonance imaging apparatus (MRI apparatus) according to the present invention will be described below with reference to the accompanying drawings. This MRI apparatus is characteristically a non-contrast MR that acquires an image representing, for example, the dynamics of blood flow as a moving object (moving body) in a subject without using a contrast agent.
It has a function of executing angiography (MRA). The pulse sequence for this non-contrast MRA includes:
A selective excitation harmonic inversion pulse is used.

FIG. 1 shows a schematic configuration of the MRI apparatus according to this embodiment. This MRI apparatus is used for patient P as a subject.
A bed part on which a magnetic field is placed, a static magnetic field generation part for generating a static magnetic field, a gradient magnetic field generation part for adding position information to the static magnetic field, a transmission / reception part for transmitting and receiving high frequency signals, control of the entire system and image reconstruction. And the control / arithmetic unit
An electrocardiographic measurement unit that measures an ECG signal as a signal representing the cardiac phase of the subject P is provided.

The static magnetic field generator comprises, for example, a superconducting magnet 101 and a static magnetic field power source 102 for supplying a current to the magnet 101, and a cylindrical opening (diagnostic space) into which the subject P is loosely inserted. The static magnetic field H ₀ is generated in the axial direction (Z-axis direction). A shim coil 114 is provided in this magnet section. A current for homogenizing the static magnetic field is supplied to the shim coil 114 from the shim coil power supply 115 under the control of the host computer 106. In the bed, the top plate on which the subject P is placed can be retractably inserted into the opening of the magnet 101.

The gradient magnetic field generator includes a gradient magnetic field coil unit 103 incorporated in the magnet 101. The gradient magnetic field coil unit 103 includes three sets (types) for generating gradient magnetic fields in the X, Y, and Z axis directions that are orthogonal to each other.
X, y, z coils 103x, 103y, 103z. The gradient magnetic field section also includes x, y, z coils 103x,
A gradient magnetic field power supply 4 for supplying current to 103y and 103z is provided. The gradient magnetic field power source 4 is a sequencer 5 described later.
X, y, z coils 103x, 103y,
A pulse current for generating a gradient magnetic field is supplied to 103z.

By controlling the pulse currents supplied from the gradient magnetic field power source 104 to the x, y, z coils 103x, 103y, 103z, the gradient magnetic fields in the three axes X, Y, Z, which are physical axes, are synthesized. , The slice direction gradient magnetic field Gs, the phase encoding direction gradient magnetic field Ge, and the readout direction (frequency encoding direction) gradient magnetic field Gr that are orthogonal to each other can be arbitrarily set and changed. The gradient magnetic fields in the slice direction, the phase encode direction, and the read direction are superimposed on the static magnetic field H ₀ .

The transmitting / receiving unit is an RF coil 107 arranged near the subject P in the imaging space inside the magnet 101, and a transmitter 108T and a receiver 1 connected to the RF coil 107.
08R and. This transmitter 108T and receiver 10
8R operates under the control of the sequencer 105. The transmitter 108T supplies an RF current pulse having a Larmor frequency for causing nuclear magnetic resonance (NMR) to the RF coil 10.
Supply to 7. The receiver 108R takes in the echo signal (high frequency signal) received by the RF coil 107, performs various kinds of signal processing such as preamplification, intermediate frequency conversion, phase detection, low frequency amplification, and filtering on the echo signal (A). / D conversion is performed to generate echo data (original data) of a digital amount corresponding to the echo signal.

The control / arithmetic unit includes a sequencer (also called a sequence controller) 105 and a host computer 10.
6, arithmetic unit 110, storage unit 111, display 112, input device 113, audio generator 116, and MR
An A expert system 120 is provided. Of these, the host computer 106 uses the stored software procedure to
It has a function of instructing the sequencer 105 of pulse sequence information and controlling the operation of the entire apparatus.

The host computer 106 carries out an imaging scan based on the pulse sequence subsequent to the preparatory work such as the positioning scan. This imaging scan is a scan that collects a set of echo data necessary for image reconstruction, and is set to a two-dimensional scan here. The imaging scan is performed by using the ECG gate method depending on the ECG signal together. The ECG gate method may not be used together depending on the case.

The pulse sequence is a three-dimensional (3D) scan or a two-dimensional (2D) scan. The form of the pulse train is SE (spin echo) method, FSE (fast SE) method, FASE (fast As
ymmetric SE) method (that is, an imaging method that combines the fast SE method and the half Fourier method), E
A PI (echo planar imaging) method or the like is used.

The sequencer 105 has a CPU and a memory, stores the pulse sequence information sent from the host computer 106, and controls the operations of the gradient magnetic field power source 104, the transmitter 108T, and the receiver 108R according to this information. At the same time, the echo data output from the receiver 108R is once input, and this is input to the arithmetic unit 1010.
Is configured to transfer to. Here, the pulse sequence information means the gradient magnetic field power source 104, the transmitter 108T, and the receiver 10 according to a series of pulse sequences.
It is all information necessary for operating the 8R, and includes, for example, information regarding the intensity of the pulse current applied to the x, y, z coils 103x, 103y, 103z, the application time, the application timing, and the like.

The arithmetic unit 110 also includes a receiver 10
Echo data output by 8R (original data or raw data)
Is input through a sequencer 105, echo data is arranged in Fourier space (also called k space or frequency space) on its internal memory, and this echo data is subjected to two-dimensional or three-dimensional Fourier transform for each set. Reconstruct image data in real space. In addition, the arithmetic unit can perform a combination process of data relating to an image, a difference calculation process, and the like as necessary.

In this synthesizing process, an adding process for adding image data of a plurality of two-dimensional frames for each corresponding pixel, 3
It includes maximum intensity projection (MIP) or minimum intensity (MIP) projection processing for selecting the maximum or minimum value in the line-of-sight direction for the dimension data. As another example of the combining process, the axes of a plurality of frames may be aligned in the Fourier space and the echo data may be combined as it is into one frame of echo data. Note that the addition processing includes simple addition processing, addition averaging processing, weighted addition processing, and the like.

The storage unit 111 can store not only the reconstructed image data but also the image data that has been subjected to the above-described combining processing and difference processing. The display 112 displays an image. Further, the operator can input information regarding an imaging condition, a pulse sequence, image synthesis and difference calculation desired by the operator to the host computer 106 via the input device 113.

Further, the electrocardiographic measurement unit is an ECG sensor 117 that is attached to the body surface of the subject to detect an ECG signal as an electrical signal, and various processing including digitization processing is performed on the sensor signal to perform host computer processing. 106 and an ECG unit 118 for outputting to the sequencer 105.
The measurement signal from the electrocardiography measurement unit is used by the sequencer 105 when executing the imaging scan. Thereby, the synchronization timing by the ECG gate method (electrocardiographic synchronization method) can be set appropriately, and the imaging scan of the ECG gate method based on the synchronization timing can be performed to collect data.

The MRA expert system 120 has a function of assisting the setting of the position of the label area and the waiting time (reversal time) TI from the inversion pulse to the excitation pulse. As the support function, a reference image acquired in advance for positioning of the imaging cross section and positioning of the label area is used, and a mark representing the label area and the blood flow labeled with the inversion pulse have an inversion time TI from the label area. After that, it is displayed on the display 112 together with the index indicating the position at which the excitation pulse is applied. In the present embodiment, two types are easily set as the support mode. The operator can selectively use the first and second types of support modes.

In the first support mode, a certain inversion time TI
And a plurality of arrival positions corresponding to various blood flow velocities v are presented under the assumed inversion time TI.
In the second support mode, a certain blood flow velocity v is assumed, and a plurality of arrival positions corresponding to various inversion times TI are presented under the assumed blood flow velocity v.

FIG. 2A shows an example of the label area setting support screen in the first support mode. The reference image 9 is an image acquired with a relatively low resolution specification by using a spin echo or an echo planar method before the main scan. In the setting scene of the label area, a rectangular mark 10 representing the label area is displayed on the reference image 9 by the MRA expert system 120, and the blood flow has various blood flow velocities from the label area after the assumed inversion time TI. A plurality of line marks 11 that represent a plurality of assumed positions that will be reached under v are indicated by dotted lines, the corresponding assumed flow velocity V, and the assumed inversion time TI are displayed. In FIG. 2, the three line marks 11 have corresponding flow velocities of 10 cm.
/ S, 20 cm / s, and 30 cm / s are displayed together with the sticky note. The relationship between the line marks 11 and the respective corresponding flow velocities can be set arbitrarily, and may be set numerically by the operator, or may be set as a default value according to the inspection site.

In each line mark 11, the corresponding flow velocity is v, and the image scale conversion distance of the distance obtained by multiplying them by the assumed inversion time TI is used as the label area mark 10.
Is arranged in parallel with the major axis of the label area mark 10 at a position separated from the end (or center) of the label area mark 10.

The operator confirms the region of interest ROI in the reference image 9 and refers to the line mark 11 for the position of the ROI, and the label region is formed by the mark 10 at a position suitable for the region of interest ROI. The inversion time TI can be set to a suitable time by changing the assumed inversion time TI with the label area fixed. Specifically, the operator operates a pointer such as a mouse of the input device 113 to move the mark 10 in the label area on the reference image 9 and changes its shape as necessary. Further, the operator taps the keyboard of the input device 113, for example, to change the assumed inversion time TI.

When the mark 10 in the label area is moved, the MRA expert system 120 uses the reference image 9
The position of the upper line mark 11 is recalculated, and the line mark 11 is displayed again at that position. As a result, the display position of the line mark 11 moves following the movement of the mark 10 in the label area.

When the assumed inversion time TI is changed, the MR
The A expert system 120 recalculates the position of the line mark 11 on the reference image 9 according to the changed inversion time TI, and redisplays the line mark 11 at that position (see FIG. 2B).

Further, the operator can select the mark 1 in the label area.
It is possible to rotate 0. FIG. 3 shows the mark 13 in the rotated label area. In order to maintain parallelism with the major axis of the mark 13 in the label area, MRA
The expert system 120 follows the rotation of the mark 13 in the label area and tilts the line mark 11. Since the object to be photographed may move in any direction from the label area, the line mark 14 is displayed as a dotted line both in parallel with the long axis of the mark 13 in the label area.

Further, the operator can select the mark 10 in the label area.
The shape of can be changed to a circle. FIG. 4 shows the mark 19 in the label area changed to a circle. To draw a concentric circle with the mark 13 in the label area,
The MRA expert system 120 changes the mark 20 indicating the arrival position of the labeled blood flow into a circle. The distance from the center or edge of the mark 13 in the label area to each mark 20 is set to a distance corresponding to TI × v, as in the case of the rectangle. For the method of inverse excitation of such a non-rectangular region, see PA Bottomtomley, et.al., Jo.
f Appl. Phys. Vol62, 4284, 1987 or CJ Har
dy, et.al., J.of Magn. Reso., Vol77, 233-250, 1988
Is shown in.

Next, the second support mode will be described. In the above-mentioned first support mode, the inversion time TI is assumed, and a plurality of arrival positions corresponding to various blood flow velocities v are presented under the inversion time TI. However, in the second support mode,
Assuming a certain blood flow velocity v, a plurality of arrival positions corresponding to various inversion times TI under the blood flow velocity v are presented.

FIG. 5A shows an example of the label area setting support screen in the second support mode. By the MRA expert system 120, a rectangular mark 15 representing the label area is displayed on the reference image 9 at a plurality of assumed positions at which blood flow flows out of the label area at an assumed flow velocity and arrives after various inversion times TI. A plurality of line marks 16 represented by dotted lines, corresponding inversion times TI, and an assumed flow velocity V are displayed.

In FIG. 5A, three line marks 16 are provided.
Are respectively corresponding inversion times TI 200 ms, 400
It is displayed together with the ms and 600 ms sticky notes. The relationship between the line mark 16 and the corresponding inversion time TI is
It can be arbitrarily set, and the operator may set a numerical value, or may be set as a default value according to the inspection site.

Each line mark 16 is separated from the end (or center) of the label area mark 15 at the scale of the image by a distance corresponding to the inversion time TI corresponding to the assumed flow velocity v. It is located at a position parallel to the long axis of the label area mark 15.

When the operator operates the pointer such as a mouse of the input device 113 to move the mark 15 in the label area on the reference image, the MRA expert system 120 follows the movement of the mark 15 in the label area. , Recalculate the position of the line mark 16 on the reference image,
The line mark 16 is displayed again at that position. As a result, the display position of the line mark 16 moves following the movement of the mark 15 in the label area. Further, when the estimated flow velocity v is changed by the operator, the MRA expert system 120 recalculates the position of the line mark 18 on the reference image according to the changed estimated flow velocity v and sets the line mark 18 at that position. It is displayed again (see FIG. 5B). Further, as in the first support mode, the mark 15 in the label area can be rotated, and the line mark 16 is tilted so that the mark 15 in the label area remains parallel to the long axis. It Further, when the shape of the mark 15 in the label area is changed to a circle, the mark 16 indicating the arrival position of the label blood flow is changed to a circle so as to draw a concentric circle with the mark 15 in the label area.

As described above, in this embodiment, the inversion time TI
The respective arrival positions at various flow velocities v are displayed as indices for position setting of the label region or adjustment of the reversal time TI, and conversely, various reversal times TI are assumed assuming the flow velocity v. By displaying the respective arrival positions in 1) as indexes for setting the position of the label area, it is possible to set the label area at a suitable position or set a suitable inversion time TI.

The MRA expert system 120 updates the standard pulse sequence and supplies the data to the sequencer 105 according to the position of the label area and the inversion time TI set as described above. Sequencer 105
According to the data of the supplied pulse sequence, the gradient magnetic field power source 104, the transmitter 108T and the receiver 108R.
The pulse sequence is executed by controlling.

Next, image data is generated by the arithmetic unit 110 from the MR data collected by the execution of the pulse sequence, and displayed on the display 112. The MRA expert system 120 has a function of providing diagnosis support information when displaying the image data.

FIG. 6 shows an example of an image display screen. 24 is a generated image, and on this image 24,
A mark 21 indicating the label area and a blood flow velocity scale 22
And are overlapped. In addition, 23 has shown the labeled blood-flow image. The velocity scale 22 is graduated with the distance on the image corresponding to the distance obtained by multiplying the inversion time TI of the pulse sequence used for imaging with various blood flow velocities v. With this scale 22, the flow path of the labeled blood flow 23 can be estimated.

Furthermore, the MRA expert system 12
0 has a function of calculating the average velocity of blood flow. FIG. 7 shows a screen when calculating the average velocity of blood flow. 25
Is a label area mark. The labeled blood flow 30 is displayed on the image together with the blood vessel image 31, for example, as a low signal. The operator operates the pointer 29 to approximately trace the path from the label area to the labeled blood flow 30 as the measurement target along the plurality of straight lines 27 at the joints (vertices) 26 according to the blood vessel image 31. Go. That is, the operator sequentially specifies the joints 26 by mouse clicking while tracing the route, which is considered to have moved the photographing target 30, with the pointer 29 from the lower end of the label area.

The MRA expert system 120 converts the distance L [m] of the polygonal line 27 into an actual distance and
The average speed is calculated by dividing the distance L by the inversion time TI [m / s], and the average speed is displayed as a numerical value 28.
As a result, the speed of the object to be imaged can be measured accurately and easily, which is convenient for the operator. If necessary, the velocity may be corrected by moving the imaging target during the echo time TE [s].

FIG. 8 shows the MRA expert system 12
0 shows the pulse sequence provided by 0. A
The part indicated by is the same as the conventional example shown in FIG. The portion indicated by B is a portion of the signal generation portion 40 in which the presaturation portion including the inversion pulse 1, the gradient magnetic field pulse for slice selection 2, and the frequency shift pulse 3 for the location of the label region is deleted from the portion A. It is a part. Functionally, only inversion pulse 1 may be deleted. The images of the A part and the B part are alternately photographed, and images are separately reconstructed to obtain two sets of image data.
By creating a difference image of the obtained image data, it is possible to suppress a signal from a non-moving part of the imaging target (here, blood flow). This makes it possible to more clearly depict a moving part. The velocity scale 22 in FIG. 6 is also displayed in the difference image in FIG. Further, the setting for calculating the average speed in FIG. 7 may be performed on the difference image in FIG.

The pulse sequence of FIG. 8 is after the pre-saturation part (inversion pulse 1, gradient magnetic field pulse for slice selection 2, frequency shift pulse 3 for location of the label region) and the signal generation part (actually). Before the imaging pulse train portion (40) of the slice pulse, the high frequency inversion pulse 1 is applied again without applying the slice selection gradient magnetic field pulse 2 and the frequency shift pulse 3 for the location of the label region.
The presaturating region may be set to a region other than the inversion excitation region of the A portion. That is, in the above method, the labeling is realized by lowering the signal in the label area with respect to the other areas. On the contrary, the label area is reduced by lowering the signal in areas other than the label area. May be extracted.

The actual imaging part shown by 40 in FIG. 8 shows the case of the FE method, but other pulse sequences such as the spin echo method,
Echo planar method, rare method (fast)
It is also possible with the true echo method and the true FISP method. In addition, the movement of the subject to be imaged is often related to the cardiac phase and body movement due to respiration, so the application of the high-frequency inversion pulse should be synchronized according to the waveforms such as ECG synchronization, pulse wave synchronization, and respiratory synchronization. You may collect it. After triggering the respiratory synchronization waveform, it may be acquired in synchronization with the first electrocardiographic waveform.

(Modification) The present invention is not limited to the above-described embodiment, but can be variously modified and implemented in the implementation stage without departing from the scope of the invention.
Further, the above embodiment includes various stages,
Various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, some constituent elements may be deleted from all the constituent elements shown in the embodiment.

[0050]

According to the present invention, the label region is set at a suitable position where the labeled blood flow can be visualized in the region of interest by a simple operation, or such a suitable reversal time is set by a simple operation. Can be set.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of magnetic resonance imaging according to the present invention.

FIG. 2 is a diagram showing an example of a label area setting screen including a flow velocity index by the MRA expert system of FIG.

FIG. 3 is a view showing another example of a label area setting screen including a flow velocity index by the MRA expert system of FIG.

FIG. 4 is a diagram showing still another example of the label area setting screen including the flow velocity index by the MRA expert system of FIG. 1.

FIG. 5: TI by the MRA expert system of FIG.
The figure which shows an example of the label area | region setting screen containing an index.

6 is a diagram showing an example of a label area mark and a flow velocity scale displayed together with a reconstructed image by the MRA expert system of FIG. 1;

FIG. 7 is a diagram showing an example of a setting screen for calculating an average speed by the MRA expert system of FIG.

FIG. 8: MR by the MRA expert system of FIG.
The figure which shows an example of the pulse sequence for A subtraction.

FIG. 9 is a diagram showing an example of a pulse sequence of a general flow imaging method.

FIG. 10 is a diagram showing a conventional label area setting screen.

[Explanation of symbols]

101 ... Magnet 102 ... Static magnetic field power supply 103 ... Gradient magnetic field coil unit 104 ... Gradient magnetic field power supply 105 ... Sequencer 106 ... Host computer 107 ... RF coil 108T ... Transmitter 108R ... Receiver 110 ... Arithmetic unit 111 ... Storage unit 112 ... Indicator 113 ... Input device 120 ... MRA expert system.

Claims (11)

[Claims] 1. An object to be imaged including a moving body in a label area in an imaging area is labeled by a magnetic resonance phenomenon by applying a specific high frequency pulse during application of a gradient magnetic field under a predetermined pulse sequence. A magnetic resonance imaging apparatus that acquires an image labeled with the imaging target by performing an operation for collecting a signal from the imaging region after a waiting time from the high-frequency pulse; A means for displaying on the reference image, an input means for moving the mark representing the label area to an arbitrary position and transforming it into an arbitrary shape, the pulse according to the position and shape of the input label area. A magnetic resonance imaging apparatus comprising: means for editing a sequence. 2. With a mark representing the label area,
The magnetic resonance imaging apparatus according to claim 1, wherein an index indicating an assumed position where the moving body arrives from the label area after the waiting time is displayed on the reference image. 3. A mark representing the label area,
The magnetic field according to claim 1, wherein indexes indicating a plurality of assumed positions at which the moving body arrives from the label area after a plurality of waiting times under an assumed flow velocity are displayed on the reference image. Resonance imaging device. 4. The magnetic resonance imaging apparatus according to claim 3, wherein the position of the index on the reference image changes according to the change of the assumed flow velocity. 5. Along with a mark representing the label area,
The index indicating a plurality of assumed positions that the moving body arrives from the label area under the waiting time under a plurality of assumed speeds is displayed on the reference image. Magnetic resonance imaging equipment. 6. The magnetic resonance imaging apparatus according to claim 5, wherein the position of the index on the reference image changes according to the change of the waiting time. 7. The mark representing the label area is displayed on the acquired image.
The described magnetic resonance imaging apparatus. 8. The magnetic resonance imaging apparatus according to claim 1, wherein a velocity or a time scale is displayed on the acquired image together with a mark representing the label area. 9. The moving distance or the average moving speed of the moving body moved during the waiting time is calculated based on the moving path of the moving body traced on the acquired image, and the moving distance or the average moving speed is calculated. The magnetic resonance imaging apparatus according to claim 1, further comprising means for displaying together with the image. 10. Under the first pulse sequence, a specific high-frequency pulse is applied during the application of the gradient magnetic field to magnetically label the imaging target including the moving body in the label area within the imaging area. A first labeled after the waiting time from the radio frequency pulse by performing an operation for collecting a signal from the imaging region,
Of the imaged object and performing an operation for collecting a signal from the imaging region without applying the specific high-frequency pulse under the second pulse sequence, A magnetic resonance imaging apparatus characterized by acquiring two images. 11. A difference image is generated by subtracting the first and second images from each other.
The described magnetic resonance imaging apparatus.