JP2003265432A - Magnetic resonance imaging method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic resonance imaging method and apparatus, capable of obtaining a sensitivity distribution of a plurality of RF coils and tomographic image by a plurality of RF coils having high S/N ratio by one time imaging. <P>SOLUTION: Raw data of the RF coils is added after the phase correction corresponding to the RF coil positions to re-configure an image, thereby obtaining uniform image information having uniform sensitivity, and the sensitivity distribution of image data in performing image synthesis processing is corrected using the uniform image information, whereby synthetic image information with high S/N ratio and good uniformity of sensitivity can be obtained by one time imaging. <P>COPYRIGHT: (C)2003,JPO

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 method and apparatus for receiving a plurality of magnetic resonance signals by a plurality of RF coils and synthesizing a tomographic image from the plurality of received signals.

[0002]

2. Description of the Related Art In recent years, a plurality of receiving RF coils are arranged and a new tomographic image is image-synthesized from a plurality of tomographic images obtained by Fourier transforming magnetic resonance signals from the plurality of receiving RF coils. Done. According to this, the S / N (signal to
The tomographic image information with a high noise ratio is acquired, and this S /
It is possible to acquire synthetic image information having a high S / N ratio by using tomographic image information having a high N ratio.

On the other hand, since a plurality of tomographic image information are combined into one composite image, if the tomographic image information having poor sensitivity uniformity is combined, the sensitivity uniformity of the combined image information is also deteriorated. Therefore, when the images are combined, the reception RF coil having a good uniformity, for example, a body coil incorporated in the main body of the magnetic resonance imaging apparatus, obtains the tomographic image information for the uniformity correction. Then, based on this tomographic image information, sensitivity distributions of the plurality of reception RF coils are obtained and corrected.

[0004]

However, according to the above conventional technique, it is necessary to acquire the tomographic image twice. That is, it is necessary to perform imaging with the body coil and imaging with a plurality of receiving RF coils.

In particular, performing the tomographic image acquisition twice is
This means that the imaging time becomes long, which not only imposes a heavy burden on the patient, but also causes the patient to move during imaging.
Further, since the patient moves during imaging, the imaging position of the patient changes, and the correction of the sensitivity distribution of the reception RF coil is also a factor causing an error.

From these facts, the sensitivity distributions of a plurality of RF coils and the plurality of Rs having a high S / N ratio can be obtained by one imaging.
How to realize a magnetic resonance imaging method and apparatus capable of acquiring a tomographic image by an F coil is extremely important.

The present invention has been made in order to solve the above-mentioned problems of the prior art.
An object of the present invention is to provide a magnetic resonance imaging method and apparatus capable of acquiring sensitivity distributions of a plurality of RF coils and tomographic images by the plurality of reception RF coils having a high S / N ratio.

[0008]

[Means for Solving the Problems]
In order to achieve the object, the magnetic resonance imaging method according to the invention of the first aspect provides a plurality of RFs that are not in magnetic coupling.
A magnetic resonance signal is received by the coil, the magnetic resonance signal is collected from the RF coil, Fourier transform is performed using the magnetic resonance signal information collected, and image information generated by the Fourier transform is further converted. A magnetic resonance imaging method for synthesizing images by data processing,
The data processing adds a plurality of the magnetic resonance signal information after phase correction, obtains sensitivity distribution information of the RF coil based on the added magnetic resonance signal information, and further, the sensitivity distribution information. Is used to correct the sensitivity distribution of the image information.

According to the invention of the first aspect, a plurality of magnetic resonance signal information are added after the phase correction by data processing, and the sensitivity distribution of the RF coil is based on the added magnetic resonance signal information. Since the information is acquired and the sensitivity distribution of the image information is corrected using this sensitivity distribution information, a plurality of RFs acquired by one imaging
From the magnetic resonance signal information of the coils, both the sensitivity distribution of each RF coil and the tomographic image information with a high S / N ratio can be acquired. By correcting the tomographic image information with the sensitivity distribution, the S / N It is possible to obtain tomographic image information having a high ratio and good sensitivity uniformity, and thus it is possible to obtain combined image information having a high S / N ratio and good sensitivity uniformity.

According to the magnetic resonance imaging apparatus of the invention of the second aspect, there are a plurality of Rs that are in a relationship of not being magnetically coupled.
An RF coil unit including an F coil, a data collection unit that collects a magnetic resonance signal received by the RF coil unit, a Fourier transform unit using the magnetic resonance signal information of the data collection unit, and a Fourier transform unit. A data processing unit having an image synthesizing unit for synthesizing the image information to be imaged, the data processing unit including a phase correcting unit for phase correcting a plurality of the magnetic resonance signal information; Using the sensitivity distribution information, the addition means for adding the phase-corrected magnetic resonance signal information, the sensitivity distribution acquisition means for obtaining the sensitivity distribution information of the RF coil based on the added magnetic resonance signal information, Sensitivity correction means for correcting the sensitivity distribution of the image information.

According to the invention of the second aspect, the data processing section causes the phase correcting means to phase-correct the plurality of magnetic resonance signal information, and the adding means adds the phase-corrected magnetic resonance signal information. Based on the added magnetic resonance signal information, the sensitivity distribution acquisition unit obtains the sensitivity distribution information of the RF coil, and the sensitivity correction unit corrects the sensitivity distribution of the image information using the sensitivity distribution information. ,
It is possible to acquire both the sensitivity distribution of each RF coil and the tomographic image information with a high S / N ratio from the magnetic resonance signal information of the plurality of RF coils acquired by one imaging. By performing correction based on the sensitivity distribution, it is possible to obtain tomographic image information having a high S / N ratio and good sensitivity uniformity, and thus obtain composite image information having a high S / N ratio and good sensitivity uniformity. it can.

Further, according to the magnetic resonance imaging apparatus of the invention of the third aspect, the phase correction means includes a plurality of Rs.
It is characterized in that the phase amount of the magnetic resonance signal information is corrected according to the reception position of the F coil.

According to the invention of the third aspect, since the phase correcting means corrects the phase amount of the magnetic resonance signal information according to the receiving positions of the plurality of RF coils, the RF coils having different positions are used. It is possible to perform phase correction on the magnetic resonance signal information of 1 to obtain magnetic resonance signal information of the same phase.

Further, according to the magnetic resonance imaging apparatus of the invention of the fourth aspect, the sensitivity distribution acquisition means is uniform image information generated by the Fourier transform from the magnetic resonance signal information obtained by the addition means. Is provided from the image information.

According to the invention of the fourth aspect, the sensitivity distribution acquisition means uses the sensitivity distribution computing means to convert the uniform image information generated by the Fourier transform of the magnetic resonance signal information obtained from the adding means into the image information. Therefore, it is possible to extract and obtain only the sensitivity distribution of the RF coil.

According to the magnetic resonance imaging apparatus of the invention of the fifth aspect, the sensitivity distribution acquisition means performs a low-pass filter processing on the magnetic resonance signal information obtained by the addition means. It is characterized by comprising means.

According to the invention of the fifth aspect, since the sensitivity distribution acquisition means performs the low-pass type filter processing on the magnetic resonance signal information obtained from the addition means by the filter processing means, It is possible to remove the noise component contained in the component or to separate the sensitivity distribution and the object information.

Further, according to the magnetic resonance imaging apparatus of the invention of the sixth aspect, the sensitivity correction means has the sensitivity distribution value having the same pixel position as the pixel position of the sensitivity distribution value. It is characterized by comprising a correction calculation means for dividing by a value.

According to the invention of the sixth aspect, the sensitivity correction means divides the sensitivity distribution value by the correction calculation means by the image information value having the same pixel position as the pixel position of the sensitivity distribution value. Therefore, the image information of each RF coil can have a uniform sensitivity distribution.

According to the magnetic resonance imaging apparatus of the seventh aspect of the present invention, the image synthesizing means synthesizes the image information corrected by the sensitivity correcting means.

According to the invention of the seventh aspect, since the image synthesizing means synthesizes the image information corrected by the sensitivity correcting means, it is possible to obtain a synthesized image having a uniform sensitivity distribution. .

According to the magnetic resonance imaging apparatus of the invention of the eighth aspect, the image synthesizing means synthesizes the image information by addition. According to the invention of the eighth aspect, since the image synthesizing means synthesizes the image information by addition, as shown in the phased array method, the tomographic image portions having a high S / N ratio are pasted together. It can be a single composite image.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the magnetic resonance imaging method and apparatus according to the present invention will be described below with reference to the accompanying drawings. The present invention is not limited to this. (Embodiment 1) First, the overall configuration of a magnetic resonance imaging apparatus according to Embodiment 1 of the present invention will be described. Figure 1
FIG. 1 is a block diagram showing an overall configuration of a magnetic resonance imaging apparatus which is Embodiment 1 of the present invention. In FIG. 1, the magnetic resonance imaging apparatus is a magnetic system (magne).
t system) 100. The magnet system 100 includes a main magnetic field coil unit 102, a gradient coil 106, a transmission coil 108 that is an RF coil, and a reception coil unit 110. Each of these coil portions has a substantially cylindrical shape and is arranged coaxially with each other.
The subject 1 to be imaged is placed in a cradle (cr) in a substantially cylindrical internal space (bore) of the magnet system 100.
It is carried in and carried out by a carrying means (not shown).

The main magnetic field coil 102 forms a static magnetic field in the internal space of the magnet system 100. The direction of the static magnetic field is substantially parallel to the direction of the body axis of the subject 1. That is, a so-called horizontal magnetic field is formed. The main magnetic field coil 102 is configured by using, for example, a superconducting coil. Needless to say, a normal conductive coil or the like may be used instead of the superconductive coil.

The gradient coil 106 generates three gradient magnetic fields for imparting gradients to the static magnetic field strength in the directions of three mutually perpendicular axes, ie, the slice axis, the phase axis and the frequency axis.

The transmitting coil 108 forms a high frequency magnetic field for exciting magnetic resonance in the body of the subject 1 in the static magnetic field space. In addition, the receiving coil unit 110 includes the cradle 1
The magnet system 1 is placed on the body 20 and is placed together with the subject 1.
00 is arranged at the center. This receiving coil unit 110
Receives the magnetic resonance signal excited in the body of the subject 1 by the transmission coil 108.

A gradient driver 130 is connected to the gradient coil 106. The gradient driver 130 includes the gradient coil 106.
A drive signal is applied to the to generate a gradient magnetic field. The gradient drive unit 130 has three-system drive circuits (not shown) corresponding to the three-system gradient coils in the gradient coil 106.

A transmission driver 140 is connected to the transmission coil 108. From the transmission driver 140 to the transmission coil 10
A drive signal is given to 8 to transmit an RF pulse, and the transmission coil 108 forms an RF magnetic field in the central portion of the magnet system 100 from the transmitted RF pulse to bring the subject 1 into an excited state of magnetic resonance.

The receiving coil section 110 includes a data collection section 1
50 is connected. The data collection unit 150 samples the reception signal received by the reception coil unit 110 (sa
capturing) and collect it as digital data. It also has a function of selecting signals from a plurality of receiving coils and adding them.

The gradient drive unit 130, the transmission drive unit 140, and the data collection unit 150 include a scan controller (sc).
An controller 160 is connected. Scan controller section 160 which is a reception control section
Controls the gradient driving unit 130 and the data collecting unit 150 to perform photographing.

The output side of the data collection unit 150 is connected to the data processing unit 170, and the data collected by the data collection unit 150 is input to the data processing unit 170. The data processing unit 170 is configured using, for example, a computer or the like. The data processing unit 170 has a memory (not shown), and this memory stores programs for the data processing unit 170 and various data.

The data processing section 170 is connected to the scan controller section 160. The data processing unit 170 is above the scan controller unit 160 and controls it. The function of this apparatus is realized by the data processing unit 170 executing a program stored in the memory.

The data processing section 170 includes a data collection section 15
0 stores the collected data in memory. A data space is formed in the memory, and this data space constitutes a two-dimensional Fourier space. Data processing unit 1
Reference numeral 70 reconstructs an image of the subject 1 by performing a two-dimensional Fourier transform on the data in the two-dimensional Fourier space.

A display unit 180 and an operation unit 190 are connected to the data processing unit 170. The display unit 180 includes a graphic display.
ay) and the like. The operation unit 190 includes a keyboard having a pointing device and the like.

The display section 180 displays the reconstructed image and various information output from the data processing section 170. The operation unit 190 is operated by the user and inputs various commands and information to the data processing unit 170. A user interactively operates the apparatus through the display unit 180 and the operation unit 190.

Next, a specific structure of the receiving coil section 110 shown in FIG. 1 will be described with reference to FIG. In FIG. 2, four rectangular coils 210 to 240 are connected to the coils 210 and 23.
The coil surface of 0 and the coil surfaces of the coils 220 and 240 are arranged on the cylindrical surface so as to face each other. The subject 1 is placed within a ring-shaped cross section composed of the coils 210 to 240. Here, the rectangular coils 210-2
Each of 40 has approximately 10% of adjacent coil and coil surface.
Overlapping. This eliminates the magnetic coupling generated between the adjacent coils.

Further, the magnetic resonance signals received by the coils 210 to 240 are received by the preamplifiers 212 to 242 having a low input impedance and sent to the data collecting section 150 via the cable. A parallel resonance circuit (not shown) is connected between the coils 210 to 240 and the preamplifiers 212 to 242, and the resonance frequency of the parallel resonance circuit is set to the resonance frequency when magnetically coupled to the opposing coil. ing. Therefore, the parallel resonance circuit is in a high impedance state at the resonance frequency, and magnetic coupling between the opposing coils can be eliminated.

Subsequently, the data collection unit 15 will be described with reference to FIG.
A specific configuration of 0 will be described. The data collection unit 150
The magnetic resonance signals received by the coils 210 to 240 of the receiving coil unit 110 are received via the preamplifiers 212 to 242. The magnetic resonance signals input from the preamplifiers 212 to 242 are received and amplified by the receivers 320 to 326, and are sent to the detector 330. The detection section 330 performs detection and shifts the resonance frequency component of the magnetic resonance signal to the low frequency side. After that, in the A / D conversion unit 340, the analog signal is converted into a digital signal, and then transferred to the data processing unit 170.

Subsequently, the data processing unit 17 will be described with reference to FIG.
A specific configuration of 0 will be described. The data processing unit 170
It has a central processing unit 410, a high-speed processing unit 420, an image memory 430, and a data bus 460. The central processing unit 410 receives the data processing unit 1 via the data bus 460.
Controls and controls the entire 70. Image memory 430
Stores the image information whose amount of information is enormous, for example, the image information received by the coils 210 to 240 is digitized by the A / D converter 340 and stored as raw data 610. The high-speed arithmetic processing unit 420 uses the image memory 430.
The uniform image information 620 and the sensitivity map information 63 from the raw data 610 accumulated in
0, image data 640, composite image information 650, etc. are generated by high-speed calculation and stored in the image memory 430.

The high-speed arithmetic processing unit 420 also performs phase correction on the raw data 610 stored in the image memory 430 according to the magnetic resonance signal reception positions of the coils 210 to 240. For example, the magnetic resonance signals received by the coils 210 to 240 are RF signals having a phase difference of π / 2 for each coil. Therefore, with respect to the raw data 610 of the coils 220 to 240, the phase angle of two orthogonal components is π /
By making a correction of 2 to 3π / 2, the coil 220 to
The raw data 610 of 240 are all received signals having the same phase as the coil 210.

Next, the operation of the data processing section 170 will be described with reference to the flowchart of FIG. 5 and the functional block diagram of the data processing section 170 shown in FIG. First,
The operator performs a scan (step S501) and acquires raw data 610, which is magnetic resonance signal information received by the coils 210 to 240 of the subject 1. Then, the acquired raw data 610 is stored in the image memory 430.

Thereafter, the central processing unit 410 carries out uniform image acquisition processing (step S502). By this processing, uniform image information 620 having a uniform sensitivity distribution of the subject 1 is generated from the four raw data 610 for each of the coils 210 to 240 shown in FIG.

After that, the central processing unit 410 performs a sensitivity distribution acquisition process (step S503). By this processing, the coils 210 to 2 are obtained from the four raw data 610 for each of the coils 210 to 240 shown in FIG. 6 and the uniform image information 620 obtained by the uniform image acquisition processing in step S502.
Sensitivity map information 630 indicating the sensitivity distribution for each 40 is generated.

After that, the central processing unit 410 carries out an image synthesizing process (step S504). By this process,
Image data 640 is generated from the four raw data 610 for each coil 210 to 240 shown in FIG. 6, and from this image data 640 and the sensitivity map information 630 obtained in step S503, combined image information 650 with good sensitivity uniformity. To generate.

After that, the central processing unit 410 displays the composite image information 650 generated in step S504 on the display unit 1.
It is displayed on 80 (step S505), and this entire process is terminated.

Next, the uniform image acquisition process of step S502 will be described with reference to the flowchart of FIG. First, the coils 210 to 10 existing in the image memory 430.
Filter processing is performed on the four raw data 610 received in 240 (step S701). This filtering is
It is performed using a Fermi filter and has a function of extracting only low frequency components existing near the center of the wave number space on the raw data 610.

After that, phase correction is performed on the four filtered raw data 610 (step S702). At this time, since the coils 210 to 240 are arranged at equal angular intervals so as to surround the cylindrical surface enclosing the subject 1, the phase angle π is set for the three raw data 610 received by the coils 220 to 240. / 2, π, 3π / 2 corrections are added.
As a result, the three raw data 610 received by the coils 220 to 240 become magnetic resonance signals having the same phase angle as the raw data 610 received by the coil 210. The phase angle does not have to match the coil 210, and may match any of the coils 220 to 240.

Then, the four phase-corrected raw data 6
10 is added (step S703). As a result, the added magnetic resonance signals are transmitted to the rectangular coils 210 to 24.
The signal is almost the same as that of a Bird Cage type coil having an element in the overlapping portion of 0. Therefore, by reconstructing an image of this magnetic resonance signal by Fourier transform (step S704), 4
Uniform image information 620 having a high degree of sensitivity uniformity, which is approximately the same as the bird cage coil of the element, is acquired.

Next, the sensitivity distribution acquisition process of step S503 will be described with reference to the flowchart of FIG. First, the coils 210 to 10 existing in the image memory 430.
Filter processing is performed on the four raw data 610 received at 240 (step S801). This filtering is
It is performed using a Fermi filter and has a function of extracting only low frequency components existing near the center of the wave number space on the raw data 610.

Thereafter, the four filtered raw data 610 are subjected to image reconstruction by Fourier transform (step S802) to generate image data. Each image data reflecting the sensitivity distribution of the coils 210 to 240 is divided by the uniform image information 620 obtained by the uniform image acquisition process of step S502 (step S803) to obtain the sensitivity map information 630 of the coils 210 to 240.
To get.

Next, the image synthesizing process of step S504 will be described with reference to the flowchart of FIG.
First, the coils 210 to 24 existing in the image memory 430
Filter processing is performed on the four raw data 610 received at 0 (step S901). This filter processing is performed using a Fermi filter and has a function of removing high frequency noise existing near the periphery of the wave number space on the raw data 610.

After that, the four filtered raw data 610 are subjected to image reconstruction by Fourier transform (step S902), and the image data 640 is generated. An image composition calculation is performed using the image data 640 and the sensitivity map information 630 obtained by the sensitivity distribution acquisition processing of step S503 (step S903). The image composition operation is
The image data 640, which is excellent in S / N ratio but inferior in sensitivity uniformity, is divided by the sensitivity map information 630 to improve the sensitivity uniformity, and the image data 640 for each coil 210 to 240 in which the sensitivity uniformity is further improved. Is added, the combined image information 650 having a wide range of excellent S / N ratio and good sensitivity uniformity is generated.

This image composition operation is performed by the coils 210 to 24.
The parameter (parameter) representing 0 is i,
When the number of receiving coils is n and the parameter expressing the pixel position on the image data 640 or the sensitivity map information 630 acquired from each receiving coil is j, it is expressed by the following equation.

[0054]

[Equation 1]

Note that P _j is the composite image value at the pixel position j (Magnetic Resonance I).
n Medicine 1999; 42: 952-96.
2, see formula (2)). In the case of the first embodiment, the number of receiving coils is n = 4.

As described above, according to the first embodiment, the raw data 610 of the coils 210 to 240 are added after the phase correction according to the position of the receiving coil, and the image reconstruction is performed. Since the uniform uniform image information 620 is acquired and the sensitivity distribution of the image data 640 when performing the image combining process is corrected using this uniform image information 620, the raw data acquired by one imaging is acquired. Using only 610, it is possible to acquire the combined image information 650 having a high S / N ratio and good sensitivity uniformity.

Further, in this embodiment, the coils 220-
The raw data 610 of 240 is subjected to phase correction of π / 2, π, 3π / 2, and image reconstruction is performed after addition, but the opposing coils 210 and 230 and the coil 22 are opposed to each other.
The raw data of 0 and 240 are added after the phase correction of π to generate two raw data. Then, it is also possible to obtain uniform image information 620 with uniform sensitivity by obtaining the sum of squares of the two generated image data after image reconstruction of these two raw data.

Further, in the present embodiment, the case where the horizontal magnetic field type main magnetic field coil 102 is used is shown, but the present invention can be similarly applied to the case where the vertical magnetic field type main magnetic field coil is used. When the main magnetic field coil of the vertical magnetic field type is used, for example, the receiving coil unit can be formed by using a plurality of solenoid coils, so that a composite image with a good S / N ratio can be obtained.

Further, in this embodiment, the coils 220-
Although it was decided to add the raw data 610 of 240 after phase correction, the magnetic resonance signal which is an RF signal is
It is also possible to obtain the raw data which is the basis of the uniform image information 620, by performing phase shift in an analog manner and adding them before the D conversion.

Further, in this embodiment, the transmitting coil 10
Although it is assumed that the data is transmitted from the reception coil unit 110 and is received by the reception coil unit 110, the reception coil unit 110 may be configured to perform the transmission. In this case, at the time of transmission, the receiving coil unit 1
According to the position of 10, the phase of the transmitted RF signal is corrected,
The subject 1 is excited so as to be uniformly excited. (Embodiment 2) By the way, in the above-mentioned Embodiment 1, the case where four rectangular receiving coils are arranged on the surface of a cylinder is shown. However, the receiving coils are arranged in a plane and operated. Good. In the second embodiment, the case where four rectangular receiving coils are arranged in a plane is shown.

FIG. 10 is a diagram showing a specific structure of the receiving coil unit 1000 according to the second embodiment. The receiving coil unit 1000 corresponds to the receiving coil unit 110 shown in FIG. 1, and the other configuration is the same as that shown in FIG. The description is omitted.

The receiving coil section 1000 shown in FIG.
The four rectangular coils 1010 to 1040 are arranged such that the coil surfaces are aligned on the same plane. Subject 1
Are placed on a plane composed of the coils 1010 to 1040. Here, rectangular coils 1010 to 1040
In each of the above, the coil surface and the coil surface adjacent to each other substantially overlap by 10%. This eliminates the magnetic coupling generated between the adjacent coils.

The magnetic resonance signals received by the four coils 1010 to 1040 are received by the four preamplifiers 1012 to 1042 having low input impedance,
It is sent to the data collection unit 150 via a cable. Coils 1010-1040 and preamplifiers 1012-1042
A parallel resonant circuit (not shown) is connected between the two, and the resonant frequency of the parallel resonant circuit is set to the resonant frequency when magnetically coupled to the second non-overlapping coil which is the second closest. . Therefore, the parallel resonant circuit is
It becomes a high impedance state at the resonance frequency, and the magnetic coupling between the coil that is the second closest can be eliminated.

Further, four coils 1010 to 1040
Are connected to the receiving units 320 to 326 of the data collecting unit 150. The coil 1010 is in the receiving unit 320, the coil 1020 is in the receiving unit 322, and the coil 1030 is in the receiving unit 3.
24, the coil 1040 is adapted to be connected to the receiver 326.

Next, the operation in the case of using the receiving coil unit 1000 will be described. Since the same processing as that of the flowchart shown in FIG. 5 is omitted without the uniform image acquisition processing, detailed description thereof will be omitted here. Then, the receiving coil unit 1000
Only the uniform image acquisition process of will be described.

FIG. 11 shows a flowchart of the uniform image acquisition process by the receiving coil unit 1000. First, the four raw data received by the coils 1010 to 1040 existing in the image memory 430 are filtered (step S1101). This filter processing is performed using a Fermi filter, and has a function of extracting only low-frequency components existing near the center of the wave number space on the raw data 610.

After that, the four raw data that have been filtered are subjected to phase addition (step S1102). By reconstructing an image of this magnetic resonance signal by Fourier transformation (step S1103), the coils 1010 to 1040 are reconstructed.
The uniform image information 620 having substantially the same sensitivity uniformity as that of the loop coil forming the outer circumference is acquired.

As described above, according to the second embodiment, the raw data of the planar coils 1010 to 1040 are phase-added and the image is reconstructed, so that the sensitivity is uniform up to the part away from the coil surface. Since the uniform image information 620 is acquired and the sensitivity distribution of the image data 640 when performing the image combining process is corrected using the uniform image information 620, the raw data 6 acquired by one-time imaging is used.
The composite image information 650 in which the S / N ratio is high and the sensitivity uniformity is good even at a site distant from the coil surface by using only 10
Can be obtained.

[0069]

As described above, according to the present invention,
The data processing unit performs phase correction of the plurality of magnetic resonance signal information by the phase correction unit, adds the phase-corrected magnetic resonance signal information by the addition unit, and adds the sensitivity distribution based on the added magnetic resonance signal information. Since the sensitivity distribution information of the RF coil is obtained using the acquisition means and the sensitivity distribution information is used to correct the sensitivity distribution of the image information by the sensitivity correction means, a plurality of RF coils acquired by one image pickup are acquired. From the magnetic resonance signal information of S, the sensitivity distribution of each RF coil and S /
Both tomographic image information with a high N ratio can be acquired,
By correcting this tomographic image information with the sensitivity distribution,
It is said that it is possible to obtain tomographic image information having a high S / N ratio and good sensitivity uniformity, and eventually obtain composite image information having a high S / N ratio and good sensitivity uniformity from a single imaging information. Produce an effect.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of a magnetic resonance imaging apparatus.

FIG. 2 is an external view showing a receiving coil unit according to the first embodiment.

FIG. 3 is a block diagram showing a data collection unit according to the first embodiment.

FIG. 4 is a block diagram showing a data collection unit according to the first embodiment.

FIG. 5 is a flowchart showing an operation of the data collection unit according to the first embodiment.

FIG. 6 is a functional block diagram of a data collection unit according to the first embodiment.

FIG. 7 is a flowchart showing a uniform image acquisition process according to the first embodiment.

FIG. 8 is a flowchart showing a sensitivity distribution acquisition process according to the first embodiment.

FIG. 9 is a flowchart showing an image synthesizing process according to the first embodiment.

FIG. 10 is an external view showing a receiving coil unit according to the second embodiment.

FIG. 11 is a flowchart showing a uniform image acquisition process according to the second embodiment.

[Explanation of symbols]

1 subject 100 magnet system 102 main magnetic field coil 106 gradient coil 108 transmitter coil 110 Receiver coil unit 120 cradle 130 Gradient drive 140 Transmission driver 150 Data Collection Department 160 Scan controller section 170 Data processing unit 180 Display 190 Operation part 210, 220, 230, 240 coils 212, 222, 232, 242 preamplifier 320, 322, 324, 326 Receiver 330 Detection unit 340 A / D converter 410 Central processing unit 420 High-speed processing unit 430 image memory 460 data bus 610 Raw data 620 Uniform image information 630 Sensitivity map information 640 image data 650 Composite image information 1000 receiver coil 1010, 1020, 1030, 1040 Coil 1012, 1022, 1032, 1042 Preamplifier

Continued front page    (72) Inventor Akira Nabeya             127, 4-7 Asahigaoka, Hino City, Tokyo             GE Yokogawa Medical System Co., Ltd.             Within F-term (reference) 4C096 AA20 AB05 AB09 AB20 AB34                       AD02 AD10 AD23 CC06 CC31                       CC38 CC40 DB09

Claims (8)

[Claims] 1. A magnetic resonance signal is received by a plurality of RF coils that are not magnetically coupled, data of the magnetic resonance signal is collected from the RF coil, and Fourier analysis is performed using the collected magnetic resonance signal information. A magnetic resonance imaging method of converting and further synthesizing image information of image information generated by the Fourier transform by data processing, wherein the data processing adds a plurality of the magnetic resonance signal information after phase correction, A magnetic resonance imaging method comprising: acquiring sensitivity distribution information of the RF coil based on the added magnetic resonance signal information, and further correcting the sensitivity distribution of the image information using the sensitivity distribution information. 2. An RF coil unit composed of a plurality of RF coils that are not magnetically coupled, a data collection unit that collects magnetic resonance signals received by the RF coil unit, and the magnetic resonance signal information of the data collection unit. And a data processing section having an image synthesizing means for synthesizing image information generated by the Fourier transforming means, wherein the data processing section comprises a plurality of magnetic fields. Phase correction means for phase-correcting resonance signal information, addition means for adding the phase-corrected magnetic resonance signal information, and sensitivity distribution information of the RF coil based on the added magnetic resonance signal information. And a sensitivity correction unit for correcting the sensitivity distribution of the image information by using the sensitivity distribution information. Magnetic resonance imaging apparatus. 3. The magnetic resonance imaging apparatus according to claim 2, wherein the phase correction unit corrects the phase amount of the magnetic resonance signal information according to the reception positions of the plurality of RF coils. 4. The sensitivity distribution acquisition means comprises sensitivity distribution calculation means for dividing uniform image information generated by the Fourier transform from the magnetic resonance signal information obtained by the addition means, from the image information. The magnetic resonance imaging apparatus according to claim 2, wherein the magnetic resonance imaging apparatus is a magnetic resonance imaging apparatus. 5. The magnetic resonance imaging apparatus according to claim 4, wherein the sensitivity distribution acquisition unit includes a filter processing unit that filters the magnetic resonance signal information obtained by the addition unit. 6. The sensitivity correction means comprises a correction calculation means for dividing the sensitivity distribution value by the image information value having the same pixel position as the pixel position of the sensitivity distribution value. The magnetic resonance imaging apparatus according to any one of 2 to 5. 7. The magnetic resonance imaging apparatus according to claim 2, wherein the image synthesizing unit synthesizes the image information corrected by the sensitivity correcting unit. 8. The magnetic resonance imaging apparatus according to claim 7, wherein the image synthesizing unit synthesizes the image information by addition.