JP6518559B2 - Magnetic resonance imaging apparatus and method - Google Patents

Description

  The present invention relates to a magnetic resonance imaging apparatus, and more particularly to a processing technique for reducing image quality deterioration caused by a step between echoes and the like.

  A fast spin echo (hereinafter FSE) sequence, which is one imaging method in a magnetic resonance imaging (hereinafter MRI) apparatus, emits a plurality of echo signals by irradiating refocusing RF pulses at regular intervals after one excitation RF pulse irradiation. Is a high-speed sequence that can continuously collect The drawback of this sequence is that the intensity of the nuclear magnetic resonance (hereinafter NMR) signal collected for each refocusing RF pulse causes a signal attenuation as shown by the following equation due to the T2 value of the imaging tissue.

  Therefore, it is known that a point spread function (hereinafter referred to as PSF) of a Lorentzian shape is superimposed on the image space to cause blurring and ring-down artifacts.

  As a countermeasure, echo arrangement on k-space (k-space) is reversed in time direction in even numbered shooting in even numbered shooting, and then signal addition with odd numbered data cancels out effects such as T2 attenuation. , And a method of reducing the amount have been reported (see Patent Document 1).

JP-A-11-318847

  In the above-mentioned prior art, even number addition is assumed, and in the case of multiple addition of an odd number of times such as 3, 5 etc., even-odd pairs can not be formed, so there is a problem that sufficient effects can not be obtained. is there.

  With respect to this subject, optimum weighting processing is performed for each data obtained by multiple addition imaging, amplification is performed after missing MR signals, and addition processing is performed to reduce image quality deterioration caused by T2 attenuation and the like. In the case of this method, the noise processing is also amplified by the weighting processing, and there is a problem that the SNR is deteriorated.

  An object of the present invention is to provide an MRI apparatus and a processing method capable of solving the above-mentioned problems and reducing deterioration of image quality without deterioration of SNR even in odd-numbered additive imaging.

  In order to achieve the above object, in the present invention, an MRI apparatus is provided with a control unit that controls measurement of echo signals according to a pulse sequence, and the control unit performs imaging at even and odd imagings in addition imaging. An MRI apparatus is provided which performs a process of reversing the order of echo filling of data into k space and a process of adding data obtained by inverting the complex conjugate to surplus imaging data in which even-odd pairs can not be formed at the time of addition imaging.

  Further, in order to achieve the above object, according to the present invention, there is provided a processing method of an MRI apparatus comprising a control unit for controlling measurement of an echo signal according to a pulse sequence, the control unit comprising even and odd times in addition imaging. Processing method of the MRI apparatus which reverses the echo filling order to the k space of the imaging data, and adds the self-inverted data obtained by inverting the complex conjugate to surplus imaging data for which even-odd pairs can not be formed at addition imaging I will provide a.

  According to the MRI apparatus of the present invention, it is possible to obtain an image quality deterioration reduction effect equivalent to even-numbered addition imaging not only for even-numbered addition imaging but for even-numbered addition imaging without deterioration of the SNR.

FIG. 1 is a block diagram showing an entire configuration of an MRI apparatus according to a first embodiment. FIG. 7 is a sequence diagram showing an example of an FSE according to the first embodiment. The figure which showed the example of the signal attenuation and PSF in NEX1 imaging | photography based on Example 1. FIG. The figure which showed the example of the signal attenuation and PSF in NEX2 imaging | photography based on Example 1. FIG. The figure which showed the example of the signal attenuation at the time of adding the imaging data of NEX1 and NEX2 based on Example 1, and PSF. The figure which showed the example of the signal attenuation at the time of adding the imaging data of NEX1, NEX2, and NEX3 based on Example 1, and PSF. FIG. 8 is a diagram showing an example of surplus imaging data at the time of odd-numbered addition imaging according to the first embodiment. FIG. 7 is a diagram for explaining cancellation of signal fluctuation due to T2 attenuation or the like due to surplus imaging data and self-inversion data according to the first embodiment. FIG. 8 is a flowchart of an example of creation of self-inversion addition data according to the first embodiment; FIG. 5 is a flowchart of an example of phase correction according to the first embodiment. FIG. 7 is a diagram showing signal attenuation of self-inversion addition data according to the first embodiment. The figure which showed the signal attenuation | damping of NEX1 + NEX2 + self-inversion addition data based on Example 1. FIG. FIG. 13 is a diagram for explaining a mismatch when self-inverted data is created when k 1 space is asymmetric according to the second embodiment. FIG. 13 is a diagram for explaining the elimination of the inconsistency by combined use of half estimation processing and the like according to the second embodiment. FIG. 14 is a diagram for explaining an application example to Parallel Imaging according to the third embodiment.

  Hereinafter, preferred embodiments of the MRI apparatus of the present invention will be described in detail with reference to the attached drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments of the present invention, and the repetitive description thereof will be omitted.

  The first embodiment is an MRI apparatus including a control unit that controls measurement of an echo signal according to a pulse sequence, and the control unit is configured to fill the echo space of imaging data into k space in the even and odd imagings in addition imaging. They are an MRI apparatus which performs the process which reverses the order, and the process which adds the data which reversed the complex conjugate to the excessive imaging | photography data which can not form even-odd pair at the time of addition imaging | photography, and the processing method.

First, an MRI apparatus commonly used in all the embodiments will be described based on FIG.
FIG. 1 is a block diagram showing an entire configuration of an embodiment of an MRI apparatus. This MRI apparatus obtains a tomographic image of the subject 101 by utilizing the NMR phenomenon, and as shown in FIG. 1, the static magnetic field generating magnet 102, the gradient magnetic field coil 103 and the gradient magnetic field power supply 109, and the RF transmission coil A top plate on which the object 104 is mounted, the RF transmitting unit 110, the RF receiving coil 105, the signal processing unit 107, the measurement control unit 111, the overall control unit 112, the display unit 108, the operation unit 118, and And a bed 106 for taking in and out the inside of the static magnetic field generating magnet 102. In the present specification, the measurement control unit 111 and the overall control unit 112 are collectively referred to as a control unit.

  The static magnetic field generating magnet 102 generates a uniform static magnetic field in the direction perpendicular to the body axis of the subject 101 in the case of the vertical magnetic field type, and in the body axis direction in the case of the horizontal magnetic field type. A static magnetic field generation source of a permanent magnet system, a normal conduction system or a superconducting system is arranged around the.

  The gradient magnetic field coil 103 is a coil wound in three axial directions of X, Y and Z which is a real space coordinate system (static coordinate system) of the MRI apparatus, and each gradient magnetic field coil is a gradient magnetic field for driving it. A power supply 109 is connected to supply current. Specifically, the gradient magnetic field power supplies 109 of the respective gradient magnetic field coils are driven according to an instruction from the measurement control unit 111 described later, and supply current to the respective gradient magnetic field coils. Thereby, gradient magnetic fields Gx, Gy, Gz are generated in the three axial directions of X, Y, Z. The gradient magnetic field coil 103 and the gradient magnetic field power supply 109 constitute a gradient magnetic field generation unit.

  At the time of imaging of a two-dimensional slice plane, a slice gradient magnetic field pulse (Gs) is applied in a direction orthogonal to the slice plane (imaging cross section) to set a slice plane with respect to the subject 101. Phase encode gradient magnetic field pulses (Gp) and frequency encode (readout) gradient magnetic field pulses (Gf) are applied in the remaining two directions to encode position information of each direction in the nuclear magnetic resonance signal (echo signal). Ru.

  The RF transmission coil 104 is a coil that irradiates the subject 101 with an RF pulse, and is connected to the RF transmission unit 110 to be supplied with a high frequency pulse current. Thereby, an NMR phenomenon is induced in the spins of the atoms constituting the living tissue of the subject 101. Specifically, the RF transmission unit 110 is driven in accordance with an instruction from the measurement control unit 111 described later, amplitude-modulates the high frequency pulse, amplifies it, and then amplifies the RF transmission coil 104 disposed close to the subject 101. By supplying the RF pulse, the subject 101 is irradiated with the RF pulse. The RF transmitting coil 104 and the RF transmitting unit 110 constitute an RF pulse generating unit.

  The RF receiving coil 105 is a coil for receiving an echo signal emitted by the NMR phenomenon of the spins constituting the living tissue of the subject 101, and the echo signal received by being connected to the signal processing unit 107 is transmitted to the signal processing unit 107. Sent.

  The signal processing unit 107 performs detection processing of the echo signal received by the RF receiving coil 105. Specifically, the signal processing unit 107 amplifies the received echo signal according to an instruction from the measurement control unit 111 described later, divides it into two orthogonal signals by quadrature phase detection, For example, 128, 256, 512, etc.) sampling, A / D converting each sampling signal and converting it into a digital quantity. Accordingly, the echo signal is obtained as echo data which is time-series digital data consisting of a predetermined number of sampling data. Then, the signal processing unit 107 performs various processing on the echo data, and sends the processed echo data to the measurement control unit 111.

  The measurement control unit 111 mainly transmits various commands for echo data acquisition necessary for reconstruction of a tomographic image of the object 101 to the gradient power supply 109, the RF transmission unit 110, and the signal processing unit 107. Control unit to control these. Specifically, the measurement control unit 111 operates under the control of the general control unit 112 described later, and based on control data of a predetermined pulse sequence, the gradient magnetic field power supply 109, the RF transmission unit 110, and the signal processing unit 107. The control is repeatedly performed to irradiate an RF pulse to the subject 101 and apply a gradient magnetic field pulse, and to detect an echo signal from the subject 101, thereby reconstructing an image of the imaging region of the subject 101. Control the acquisition of the required echo data. At the time of repetition, in the case of two-dimensional imaging, the application amount of the phase encoding gradient magnetic field is changed, and in the case of three-dimensional imaging, the application amount of the slice encoding gradient magnetic field is also changed. The number of phase encodings is usually selected as 128, 256, 512, etc. per image, and the number of slice encodings is usually selected as 16, 32, 64 etc. The echo data from the signal processing unit 107 is output to the overall control unit 112 by these controls.

  The overall control unit 112 performs control of the measurement control unit 111 and control of various data processing and display and storage of processing results, and includes an arithmetic processing unit (CPU) 114, a memory 113, and a magnetic disk. And the like, and a network IF 116 that interfaces with an external network. In addition, an external storage unit 117 such as an optical disk may be connected to the overall control unit 112.

  Specifically, the measurement control unit 111 causes the execution of the imaging sequence to collect echo data, and when the echo data from the measurement control unit 111 is input, the arithmetic processing unit 114 uses the encoded information applied to the echo data. Based on this, it is stored in an area corresponding to the k 1 space in the memory 113. Hereinafter, the description to arrange echo data in the k 1 space means that the echo data is stored in an area corresponding to the k 1 space in the memory 113. Further, the echo data group stored in the area corresponding to the k 1 space in the memory 113 is also referred to as k 2 space data.

  Then, the arithmetic processing unit 114 executes processing such as signal processing and image reconstruction by Fourier transform on the k space data, and causes the display unit 108 described later to display the image of the subject 101 as a result of the processing. It is recorded in the internal storage unit 115 or the external storage unit 117, or transferred to an external device via the network IF 116.

  The display unit 108 displays the reconstructed image of the subject 101. The operation unit 118 includes a track ball, a mouse, a keyboard, and the like for inputting various control information of the MRI apparatus and control information of processing performed by the overall control unit 112. The operation unit 118 is disposed close to the display unit 108, and the operator interactively controls various processes of the MRI apparatus via the operation unit 118 while looking at the display unit 108.

FIG. 2 shows an example of a pulse sequence of FSE (Fast Spin Echo) method for acquiring a plurality of echo signals, which is executed by control of the control unit of the MRI apparatus of the present embodiment.
In this figure, RF, Gs, Gp, Gr, A / D and Signal respectively apply RF pulse, apply slice selection gradient magnetic field pulse, apply phase encode gradient magnetic field pulse, apply frequency encode gradient magnetic field pulse, analog Represents an axis showing digital conversion, acquisition of echo signal. Here, as an example, an FSE sequence for acquiring an echo signal 220 group by the A / D conversion 219 for each of a plurality of inverted RF pulses 213 for one 90 ° excitation RF pulse 208 is shown.

  In the FSE sequence, first, a slice selection gradient magnetic field pulse 209 is applied together with a 90 ° excitation RF pulse 208 for applying a high frequency magnetic field to spins in the imaging plane, and then a phase dispersion by the slice selection gradient magnetic field 209 is converged. A focus gradient magnetic field pulse 210 is applied. Thereafter, the 180 ° inversion RF pulse 213 for inverting the spin in the slice plane is repeatedly applied. As described above, in order to acquire the echo signal 220 group in each DA period 219 for one 90 ° excitation RF pulse 208, the 180 ° inversion RF pulse 213 is repeatedly applied a plurality of times. Then, every time the 180 ° reverse RF pulse 213 is applied, a slice encoding gradient magnetic field pulse 216, a phase encoding gradient magnetic field pulse 217, and a frequency encoding gradient magnetic field pulse 218 for selecting a slice are periodically applied. In the figure, reference numeral 211 denotes a frequency dephase gradient magnetic field, and 221 and 222 denote rewind gradient magnetic fields.

  This FSE sequence is a sequence for measuring a plurality of echo data after excitation by one RF pulse and arranging the echo data in one k space. The measured echo data are arranged and filled in the k-space in the same order as the measured echo order for each echo number. The imaging target nuclide of the MRI apparatus at present is a hydrogen nucleus (proton) which is a main constituent substance of a subject, as widely used in clinical practice. By imaging information on the spatial distribution of the proton density and the spatial distribution of the relaxation time of the excited state, the form or function of the human head, abdomen, limbs, etc. can be imaged two-dimensionally or three-dimensionally.

  Subsequently, in the MRI apparatus of this embodiment, a PSF which is convoluted on an image by T2 attenuation or the like in an FSE sequence or the like will be described with reference to the drawings.

  The first shooting data NEX (Number of Excitation) of the Echo array in which the k space is filled in ascending order in Echo Numbers 129 to 394 and in descending order in Echo Numbers 1 to 64 and 395 to 512 in the lower part of FIG. 1 shows the signal attenuation of the time domain and the PSF of the image domain, respectively. The second imaging data NEX2 is as shown in FIG. 4 because the echo arrangement is inverted in the time direction. The shooting data of NEX1 and the shooting data of NEX2 are also inverted in the time direction in the time domain, and there is no difference in the PSF of the image domain. FIG. 5 shows the result of adding both, ie, adding even, as a solid line. As shown in the upper part of the figure, the signal change of the Time domain is gradual, and as shown in the lower part of the figure, the PSF of the image domain also has an improvement in narrowing of the line width.

  Here, FIG. 6 shows results of PSF and the like in the case where the same addition processing is performed when the number of additions is an odd number 3. As shown in the figure, the signal attenuation after the addition processing changes more than in the case of the even number addition, and the PSF of the image domain after the addition has a wider line width. As described above, in order to take measures against this, in the case of odd-numbered additive imaging, it is considered that weighting processing is performed on even-numbered captured images, and addition is performed after matching the intensity with odd-numbered captured data Be As a result, it is possible to suppress the change in signal attenuation even during odd-numbered photographing as in even-numbered addition, and thus image quality deterioration can be reduced. However, since noise components are also raised by weighting processing, SNR is deteriorated.

  Therefore, in the configuration of the MRI apparatus of the present embodiment, the signal attenuation is improved by the self-inversion data addition processing. Here, assuming that the odd-numbered addition shooting specified by the user interface such as the operation unit 118 is 2N + 1 (N is zero), as shown in FIG. 7, even-numbered addition data obtained by adding N even-odd pairs. , And can be divided into one surplus imaging data 119. Therefore, if the influence of the signal attenuation can be canceled from the surplus imaging data 119, the image quality deterioration can be reduced. For this reason, in the configuration of this embodiment, as shown in FIG. 8, self-inverted data 120 for canceling out signal fluctuation that is the influence of T2 attenuation etc. is generated from surplus photographed data 119 itself. Be a pair. That is, after adding the extra shot data 119 and the generated self-inversion data 120, by adding it to the even-numbered addition data, it is possible to obtain a good image quality deterioration reduction effect even in the odd-numbered addition shooting.

FIG. 9 shows a flow chart of a method of realizing addition imaging in the MRI apparatus of the present embodiment described above. First, excess imaging data Mi (kx, ky) 119 from the k-space self inversion data M _FC simulating the data filled in reverse order (kx, ky) to create a 120. The self-inverted data 120 is obtained by calculating the complex conjugate from the surplus imaging data 119 and inverting it vertically and horizontally. Incidentally, when the surplus imaging data 119 and the self-inversion data 120 are subjected to 2D Fourier transformation, the absolute value image is the same but the phase is inverted due to the conjugate symmetry of the k space. This self-inverted data 120 can be thought of as filling the k-space in reverse order with respect to the surplus imaging data 119, so by adding these to obtain self-inverted added data, the effects such as T2 attenuation are offset. can do. Also, due to the nature of the absolute value image being the same, there is no degradation of SNR even if it is added.

However, due to a slight deviation between the center of the k space and the echo peak in the surplus imaging data 119, when added with the self-inverted data 120, the low frequency phase interferes and becomes shading. Therefore, the phase corrections 121 and 122 are performed, the phase of the low frequency band is removed from each image, M_Cori (x, y) and M_Cor _FCC (x, y) are added, and then added to make self-inversion addition data M_out. (x, y) 123 can be obtained to suppress shading. One specific example of the phase corrections 121 and 122 is shown in FIG. The phase corrections 121 and 122 have the same configuration, and the input data and the phase correction data are indicated by Min (kx, ky) and p ^* (x, y) Min (x, y), respectively. Here, p ^* (x, y) = exp (-iangle {M _Low (x, y)}).

  According to the configuration of the present embodiment described above, it is possible to create self-inversion addition data 123 with reduced image quality deterioration due to T2 attenuation or the like from surplus photographed data 119 itself.

  FIG. 11 shows the improvement results of the influence of T2 attenuation etc. of even-numbered addition data (NEX1 + NEX 2), surplus imaging data (NEX 1), and self anti-addition data (NEX1 + self-inversion data) in the addition frequency NEX3. In the self-inversion addition data, an improvement in which the signal change of the surplus imaging data becomes gentle as in the even-numbered addition data is recognized. As shown in FIG. 12, an even number such as (NEX1 + NEX2 + NEX3) can be obtained by adding the even-numbered addition data (NEX1 + NEX2) obtained above and the self-inversion addition data (NEX3 + self-inversion data). Even in the case of the time-addition shooting 2N + 1, the reduction effect of the image quality deterioration due to the T2 attenuation and the like can be obtained. In addition, since the present invention does not include processing for raising noise, there is no deterioration in SNR. Although the surplus imaging data has been described as 2N + 1, any imaging data may be treated as the surplus imaging data as long as it is the odd-numbered imaging data.

  In the above description of the first embodiment, even in the case of single shooting of N = 0, that is, NEX = 1, as odd-numbered addition shooting with odd-numbered addition shooting is 2N + 1 (N starts from 0). The calculation process of the self-inversion addition data of this embodiment can be used. In this case, there is no even-numbered addition data. That is, the photographing is one odd number of times of photographing, and the control unit performs processing of adding self-inverted data obtained by inverting the complex conjugate to the photographed data obtained in the first time. You can get the effect.

  Further, it is needless to say that the calculation processing of the self-inversion addition data of the present embodiment can be used for every shooting data for the number of additions specified by the UI. In this case, image quality deterioration due to T2 attenuation and the like is reduced for each set of shooting data, and then all shooting data is added.

  According to the present embodiment described above, image quality deterioration due to T2 attenuation and the like can be reduced equally in the case of even-numbered imaging without deterioration in SNR even in odd-numbered additive imaging.

  The second embodiment is an embodiment of an MRI apparatus which applies calculation processing of self-inversion addition data at the time of half scan and half echo imaging. That is, the imaging data of the MRI apparatus of the present embodiment is data obtained by half scan imaging or partial echo imaging, and the control unit adds self-inverted data obtained by inverting the complex conjugate to the imaging data. It is an Example of the MRI apparatus of the structure which performs a process.

  During Half Scan, in which only a part of phase encoding is filled in, or in partial echo photography, in which echo is sampled partially during frequency encoding, the imaging data is arranged asymmetrically with respect to k space, so the complex conjugate is inverted as it is And, as shown in FIG. 13, a mismatch occurs at the filling point. In this case, it is possible to use the above-described calculation process of the self-inversion addition data by creating non-filling data by the half estimation process and creating symmetrical imaging data in the k 2 space. FIG. 14 shows an example of producing self-inverted data 126 by inverting the complex conjugate and up and down, left and right, after obtaining the estimated surplus imaging data 125 by half estimation with respect to the redundancy imaging data 124 obtained by half scan. The half estimation process may be performed after the self-inverted data is generated. Further, as the algorithm of the half estimation process, a commonly used algorithm may be used.

  Example 3 is an example of an MRI apparatus that uses calculation processing of self-inversion addition data in the case of parallel imaging (Parallel Imaging). That is, in the MRI apparatus of this embodiment, the imaging data is data obtained by parallel imaging, and the control unit performs processing of adding self-inverted data obtained by inverting the complex conjugate to the imaging data. It is an embodiment of an MRI apparatus.

  In the present embodiment, the self-inversion / addition process may be applied to either before or after the expansion of data obtained by parallel imaging. FIG. 15 shows a schematic configuration when self-reversal processing is performed on the developed image of this embodiment. Since the phase of the self-inversion addition data is lost due to the above-described phase correction processing, it is necessary to consider the phase correction to be restored depending on the Parallel Imaging algorithm when applying it before expansion. . That is, 2D FFT and various corrections are performed on each of a plurality of thinned data 126 obtained by Parallel Imaging, and the obtained data 127 is subjected to SENSE expansion to create an expanded image 128, and self-inversion processing is performed, and self-inversion is performed. The addition data 129 can be obtained. For Parallel Imaging, a commonly used algorithm may be used.

  The fourth embodiment is an embodiment using calculation processing of self-inversion addition data in 3D measurement. That is, in the present embodiment, it is data obtained by imaging the imaging data by 3D measurement, and the control unit inverts the complex conjugate of the surplus imaging data for each slice axis, phase axis, and frequency axis of 3Dk space. This is an embodiment of an MRI apparatus configured to create self-inverted data. In the case of 3D measurement, the complex conjugate of the obtained surplus imaging data is subjected to space inversion so that inversion is performed for each slice axis, phase axis and frequency axis of 3Dk space including slice axes. . Alternatively, the present invention may be applied to a 2D cross section composed of a slice axis and a phase axis, or a slice axis and a frequency axis.

  The fifth embodiment is an embodiment in which calculation processing of self-inversion addition data is used when addition is performed after excluding image data whose image quality degradation is severe due to the movement of body and the like in multiple addition imaging of a body trunk and the like. is there.

  In such applications where image data with severe deterioration in image quality is excluded due to the influence of body movement etc. in multiple addition shooting, there is one surplus shooting data for which even / odd pairs can not be created with shooting data remaining after exclusion There may be more than one. For example, when the image quality deterioration is severe in all the odd-numbered imaging data, removing them may leave only the even-numbered imaging data and may not create even or odd pairs. In the present embodiment, processing is performed to add data obtained by inverting the complex conjugate to surplus imaging data in which even-odd pairs can not be formed during such addition imaging.

  As described above, in this embodiment, the calculation processing of the self-inversion addition data is used not only in the case of odd-numbered addition imaging but also in the case where even-odd pairs can not be formed. In the case of this embodiment, it is considered that one or more surplus imaging data exist in imaging data with less image quality deterioration, self inversion data is created using the surplus imaging data, and each is added as an even-odd pair. . That is, in the present embodiment, since the surplus imaging data is used as self-inversion addition data by using self-inversion data, addition processing is performed after image quality deterioration due to T2 attenuation or the like is reduced.

  The present invention is not limited to the embodiments described above, but includes various modifications. For example, although the FSE sequence of the MRI apparatus has been described as an example in the description of the above embodiment, the present invention is not limited to the FSE sequence, and image quality deterioration occurs due to echo etc. such as EPI (Echo Planer Imaging) sequence. The same applies to sequences. Also, the above-described embodiments have been described in detail for a better understanding of the present invention, and are not necessarily limited to those having all the configurations of the description. In addition, part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. In addition, with respect to a part of the configuration of each embodiment, it is possible to add, delete, and replace other configurations.

  Furthermore, although each configuration, function, processor, etc. mentioned above explained the example which creates the program run with CPU which realizes a part or all of those, a part or all of them are designed by an integrated circuit, for example It goes without saying that the present invention may be realized by hardware as well.

101 subjects
102 Static magnetic field generating magnet
103 gradient coil
104 RF transmitter coil
105 RF receiver coil
106 beds
107 Signal processing unit
108 Display
109 Gradient field power supply
110 RF transmitter
111 Measurement control unit
112 General control unit
113 memory
114 arithmetic processing unit (CPU)
115 Internal storage unit
116 Network IF
117 External storage unit
118 Operation unit
119, 124 surplus shooting data
120, 126 Self-inverted data
121, 122 phase correction
123, 129 Self-inversion addition data
127 Thinning data
128 unfolded image
208 90 ° excitation RF pulse
209, 214 slice selection gradient magnetic field pulse
210, 215 refocusing gradient magnetic field pulse
211 frequency dephasing gradient magnetic field
212 crusher gradient magnetic field pulse
213 180 ° Inverted RF Pulse
216 slice encode gradient magnetic field pulse
217 phase encoding gradient magnetic field pulse
218 frequency encoding gradient pulses
219 A / D period
220 echo signal
221, 222 rewind gradient magnetic field pulse

Claims (7)

A magnetic resonance imaging (MRI) apparatus comprising a control unit that controls measurement of an echo signal according to a pulse sequence,
The control unit
A process of reversing the order of echo filling of the imaging data into the k space in the even-numbered and odd-numbered imaging in additive imaging;
A process of creating self-inverted data obtained by inverting the complex conjugate of surplus imaging data in which even-odd pairs can not be formed at the time of the addition imaging ;
After phase correction of each of the surplus imaging data and the self-inversion data, a process of adding the self-inversion addition data is performed.
MRI apparatus characterized by The MRI apparatus according to claim 1,
The addition shooting is 2N + 1 (N is an integer starting from 0) times of addition shooting,
The control unit
Performing processing of adding self-inverted data obtained by inverting the complex conjugate to the imaging data obtained at the 2N + 1 (N is an integer starting from 0) times;
MRI apparatus characterized by The MRI apparatus according to claim 1,
The imaging data is data obtained by half scan imaging or partial echo imaging,
The control unit
Wherein Taking the shadow data, it performs a process of adding the self-inverting data obtained by inverting the complex conjugate,
MRI apparatus characterized by The MRI apparatus according to claim 1,
The imaging data is data obtained by parallel imaging,
The control unit
Wherein Taking the shadow data, it performs a process of adding the self-inverting data obtained by inverting the complex conjugate,
MRI apparatus characterized by The MRI apparatus according to claim 1,
It is data obtained by shooting the shooting data by 3D measurement,
The control unit
The complex conjugate is inverted for each slice axis, phase axis, and frequency axis of the 3D k space with respect to the surplus imaging data to create the self-inverted data.
MRI apparatus characterized by The MRI apparatus according to claim 1,
The surplus imaging data is the corresponding odd-numbered imaging data when the even-numbered imaging data is data with image quality deterioration,
The control unit generates and adds the self-inversion data from the odd-numbered photographing data.
MRI apparatus characterized by What is claimed is: 1. A processing method of an MRI apparatus comprising: a control unit that controls measurement of an echo signal according to a pulse sequence,
The control unit reverses the order in which echo data is filled in the k space of imaging data in even-numbered and odd-numbered imaging in additive imaging,
Create self-inverted data by inverting the complex conjugate of surplus imaging data that can not form even-odd pairs during additive imaging ,
After phase correction each of the surplus imaging data and the self-inversion data, they are added to obtain self-inversion addition data .
Processing method of the MRI apparatus characterized by the above.

Images