JP2006212171A - Magnetic resonance imaging system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To generate images of high contrast and to improve the quality of the images. <P>SOLUTION: A magnetic resonance imaging system collects a first magnetic resonance signal MR1 obtained in first echo time TE1, a second magnetic resonance signal MR2 obtained in second echo time TE2 shorter than the first echo time TE1, and a third magnetic resonance signal MR3 obtained in third echo time TE3 longer than the first echo time TE1 by the difference value t of the first echo time TE1 and the second echo time TE2. Then, a first image I1, a second image I2, and a third image I3 are generated on the basis of the first magnetic resonance signal MR1, the second magnetic resonance signal MR2, and the third magnetic resonance signal MR3, a fourth image I4 is generated by averaging the second image I2 and the third image I3, and the first image I1 and the fourth image I4 are displayed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a magnetic resonance imaging apparatus.

  Magnetic resonance imaging (MRI) apparatuses are used in various fields such as medical applications and industrial applications.

The magnetic resonance imaging apparatus excites the spin of the subject in the static magnetic field space by a nuclear magnetic resonance (NMR) phenomenon, and based on the magnetic resonance (MR) signal generated along with the excitation, An image of the slice is generated (see, for example, Patent Document 1 and Patent Document 2).
JP 2001-178700 A JP 2003-61928 A

  When imaging a subject using a magnetic resonance imaging apparatus, the subject is imaged by various imaging methods depending on the purpose of imaging. For example, for the purpose of enhancing T2 * attenuation, or for the purpose of comparing an image when water and fat in the subject are in phase with an image when the phase is opposite, a gradient echo is used. According to the method, two echoes are collected at different echo times within a repetition time (TR), and two images are taken.

  However, when the gradient echo method is used to image an enhanced image for T2 * attenuation as in the prior art, an image with sufficient contrast cannot be obtained because of being affected by T2 attenuation. In some cases, it is difficult to improve image quality. Similarly, when imaging both an image in the case where water and fat in the subject are in phase and an image in the case of opposite phase, the contrast is sufficient because it is close to the T1 contrast. In some cases, it is difficult to improve image quality. For this reason, conventionally, it has been difficult to improve the diagnostic efficiency.

  Accordingly, an object of the present invention is to provide a magnetic resonance imaging apparatus capable of improving the quality of an image of a subject and improving diagnostic efficiency.

  In order to achieve the above object, the magnetic resonance imaging apparatus of the present invention transmits an RF pulse to a subject in a static magnetic field, applies a gradient magnetic field to the subject, and a transmitter for exciting the spin of the subject. , A gradient magnetic field application unit that encodes a magnetic resonance signal from a spin excited by the RF pulse, a data collection unit that collects the magnetic resonance signal encoded by the gradient magnetic field, and a data collection unit An image generation unit that generates an image of the subject based on the magnetic resonance signal, wherein the data collection unit includes a first magnetic resonance signal obtained at a first echo time; A second magnetic resonance signal obtained at a second echo time shorter than the first echo time, and a time interval between the first echo time and the second echo time. Each third magnetic resonance signals obtained in the long third echo signal than the first echo time to the corresponding collected as the magnetic resonance signal.

  In order to achieve the above object, the magnetic resonance imaging apparatus of the present invention transmits an RF pulse to a subject in a static magnetic field, applies a gradient magnetic field to the subject, and a transmitter for exciting the spin of the subject. , A gradient magnetic field application unit that encodes a magnetic resonance signal from a spin excited by the RF pulse, a data collection unit that collects the magnetic resonance signal encoded by the gradient magnetic field, and a data collection unit An image generation unit that generates an image of the subject based on the magnetic resonance signal, wherein the data collection unit includes a first magnetic resonance signal obtained at a first echo time; Each of the second magnetic resonance signal obtained at a second echo time different from the first echo time is converted into the magnetic resonance signal by a spin echo method. To collect Te.

  In order to achieve the above object, the magnetic resonance imaging apparatus of the present invention transmits an RF pulse to a subject in a static magnetic field, applies a gradient magnetic field to the subject, and a transmitter for exciting the spin of the subject. , A gradient magnetic field application unit that encodes a magnetic resonance signal from a spin excited by the RF pulse, a data collection unit that collects the magnetic resonance signal encoded by the gradient magnetic field, and a data collection unit An image generation unit that generates an image of the subject based on the magnetic resonance signal, wherein the data collection unit sends a 90 ° RF pulse to the transmission unit by a spin echo method. Transmitting to the subject and sending a 180 ° refocusing pulse to the subject to the subject after a lapse of a first time from the 90 ° RF pulse. In addition, a 90 ° RF pulse is transmitted to the subject by the first magnetic resonance signal obtained at the echo time after the first time has elapsed from the 180 ° refocusing pulse and the spin echo method, and the subject is transmitted. After the 90 ° RF pulse has passed a second time different from the first time, the same time as the echo time at which the first magnetic resonance signal was collected after causing the transmitter to transmit a 180 ° refocusing pulse to the subject. Each of the second magnetic resonance signals obtained at the echo time is collected as the magnetic resonance signal.

  According to the present invention, it is possible to provide a magnetic resonance imaging apparatus capable of improving the quality of an image of a subject and improving diagnostic efficiency.

  Hereinafter, an example of an embodiment according to the present invention will be described with reference to the drawings.

<Embodiment 1>
FIG. 1 is a configuration diagram illustrating a configuration of the magnetic resonance imaging apparatus according to the first embodiment.

  As shown in FIG. 1, the magnetic resonance imaging apparatus includes a static magnetic field magnet unit 12, a gradient coil unit 13, an RF coil unit 14, an RF drive unit 22, a gradient drive unit 23, a data collection unit 24, The control unit 25, the cradle 26, the data processing unit 31, the operation unit 32, and the display unit 33 are included.

  Hereinafter, each component will be sequentially described.

  The static magnetic field magnet unit 12 is constituted by a pair of permanent magnets, for example, and forms a static magnetic field in the imaging space 11 in which the subject 40 is accommodated. Here, the static magnetic field magnet unit 12 forms a static magnetic field such that the direction of the static magnetic field is along the direction Z perpendicular to the body axis direction of the subject 40. The static magnetic field magnet unit 12 may be composed of a superconducting magnet.

  The gradient coil unit 13 forms a gradient magnetic field in the imaging space 11 in which a static magnetic field is formed, and adds position information to the magnetic resonance signal received by the RF coil unit 14. Here, the gradient coil unit 13 includes three systems, and forms gradient magnetic fields in each of the frequency encoding direction, the phase encoding direction, and the slice selection direction according to the imaging conditions. Specifically, the gradient coil unit 13 applies a gradient magnetic field in the slice selection direction of the subject 40 and the RF coil unit 14 selects a slice of the subject 40 to be excited by transmitting an RF pulse. The gradient coil 13 applies a gradient magnetic field in the phase encoding direction of the subject 40, and phase encodes the magnetic resonance signal from the slice excited by the RF pulse. The gradient coil unit 13 applies a gradient magnetic field in the frequency encoding direction of the subject 40, and frequency encodes the magnetic resonance signal from the slice excited by the RF pulse.

  As shown in FIG. 1, the RF coil unit 14 is disposed so as to surround the imaging region of the subject 40. In the imaging space 11 where the static magnetic field is formed by the static magnetic field magnet unit 12, the RF coil unit 14 transmits an RF pulse that is an electromagnetic wave to the subject 40 to form a high-frequency magnetic field, and in the imaging region of the subject 40. Excites proton spin. The RF coil unit 14 receives electromagnetic waves generated from the excited protons in the subject 40 as magnetic resonance signals.

  The RF drive unit 22 drives the RF coil unit 14 to transmit RF pulses in the imaging space 11 to form a high frequency magnetic field. The RF drive unit 22 includes a gate modulator (not shown), an RF power amplifier (not shown), and an RF oscillator (not shown). Based on the control signal from the control unit 25, the RF drive unit 22 modulates the signal from the RF oscillator into a signal having a predetermined timing and a predetermined envelope using a gate modulator. Then, after the signal modulated by the gate modulator is amplified by the RF power amplifier, the signal is output to the RF coil unit 14 to transmit the RF pulse.

  The gradient driving unit 23 applies a gradient pulse to the gradient coil unit 13 based on a control signal from the control unit 25 to drive the gradient coil unit 13 to generate a gradient magnetic field in the imaging space 11 in which a static magnetic field is formed. The gradient drive unit 23 includes three systems of drive circuits (not shown) corresponding to the three systems of gradient coil units 13.

  The data collection unit 24 collects magnetic resonance signals received by the RF coil unit 14 based on a control signal from the control unit 25 and outputs the magnetic resonance signals to the data processing unit 31. The data collecting unit 24 collects the magnetic resonance signals subjected to the phase encoding and the frequency encoding so as to correspond to the k space. Here, after the phase detector detects the magnetic resonance signal received by the RF coil unit 14 using the output of the RF oscillator of the RF drive unit 22 as a reference signal, the data collection unit 24 then outputs the magnetic resonance signal of the analog signal. An A / D converter converts it into a digital signal. Then, the collected magnetic resonance signals are stored in the memory and then output to the data processing unit 31.

  The control unit 25 includes a computer and a program that causes each unit to execute a predetermined pulse sequence using the computer. Then, based on the operation signal input from the operation unit 32 via the data processing unit 31, the control unit 25 applies a predetermined pulse sequence to each of the RF drive unit 22, the gradient drive unit 23, and the data collection unit 24. Control is performed by outputting a control signal for executing.

  The cradle 26 has a table on which the subject 40 is placed. The cradle unit 26 moves between the inside and the outside of the imaging space 11 based on a control signal from the control unit 25.

  The data processing unit 31 includes a computer and a program that executes predetermined data processing using the computer. The data processing unit 31 is connected to the operation unit 32 and receives an operation signal from the operation unit 32. The data processing unit 31 is connected to the control unit 25 and outputs an operation signal input to the operation unit 32 by the operator to the control unit 25. Further, the data processing unit 31 is connected to the data collecting unit 24, acquires the magnetic resonance signal collected by the data collecting unit 24, performs image processing on the acquired magnetic resonance signal, and performs an object test. Generate an image for 40 slices. For example, the data processing unit 31 performs an Fourier transform process on the magnetic resonance signal converted into a digital signal, and generates an image of the subject 40. Then, the data processing unit 31 outputs the generated image to the display unit 33.

  The operation unit 32 is configured by operation devices such as a keyboard and a mouse. The operation unit 32 is operated by an operator and outputs an operation signal corresponding to the operation to the data processing unit 31. Here, the operation unit 32 is configured so that the operator can select and input a plurality of pulse sequences according to the imaging purpose.

  The display unit 33 is configured by a display device such as a CRT. The display unit 33 displays an image of the slice of the subject 40 generated based on the magnetic resonance signal from the subject 40.

  In the magnetic resonance imaging apparatus of the above embodiment, the gradient coil unit 13 corresponds to the gradient magnetic field application unit of the present invention. Further, the RF coil unit 14 of the present embodiment corresponds to a transmission unit of the present invention. Further, the data collection unit 24 of the present embodiment corresponds to the data collection unit of the present invention. Further, the data processing unit 31 of the present embodiment corresponds to the image generation unit of the present invention. The display unit 33 of the present embodiment corresponds to the display unit of the present invention.

  Hereinafter, a magnetic resonance imaging method for imaging a slice of the subject 40 using the magnetic resonance imaging apparatus of the present embodiment will be described.

  First, after placing the subject 40 on the cradle 26, the RF coil unit 14 is installed so as to correspond to the imaging region of the subject 40. Here, the RF coil unit 14 is installed so as to image the liver portion of the subject 40. Based on the imaging conditions input to the operation unit 32 by the operator, the operation unit 32 outputs an operation signal to the control unit 25 via the data processing unit 31.

  Next, based on the imaging conditions input to the operation unit 32, the control unit 25 moves the cradle 26 on which the subject 40 is placed into the imaging space 11 where the static magnetic field is formed. Control.

  Next, based on the operation signal, the control unit 25 outputs a control signal to each of the RF drive unit 22, the gradient drive unit 23, and the data collection unit 24, and outputs an RF pulse and a gradient magnetic field to the subject 40. The magnetic resonance signals generated from the subject 40 are collected every time.

  FIG. 2 is a pulse sequence diagram illustrating a procedure in which the control unit 25 controls each unit in 1TR. FIG. 2 shows an RF pulse RF, a gradient magnetic field Gs in the slice selection direction, a gradient magnetic field Gp in the phase encoding direction, a gradient magnetic field Gr in the frequency encoding direction, and a magnetic resonance signal MR. Here, the vertical axis represents intensity, and the horizontal axis represents time.

  As shown in FIG. 2, the control unit 25 controls each unit so as to capture an image of the subject 40 by the spin echo method. That is, after the RF coil unit 14 transmits the 90 ° RF pulse for exciting the spin for the slice of the subject 40 to be a flip angle of 90 ° to the subject 40, the control unit 25 transmits the 90 ° pulse. Control is performed so that the RF coil unit 14 transmits a 180 ° refocusing pulse, which is an RF pulse that refocuses spins excited and phase-dispersed by the RF pulse, to the subject 40.

  Here, based on the imaging method input to the operation unit 32 by the operator and the imaging conditions such as the first echo time TE1, the control unit 25 transmits a 90 ° RF pulse and a 180 ° refocus pulse to the subject 40. The time points to be calculated are calculated and controlled so as to correspond to each.

  Specifically, the control unit 25 controls the 90 ° RF pulse so that the first echo time TE1 is twice the time interval τ between the transmission time of the 90 ° RF pulse and the transmission time of the 180 ° refocusing pulse. The transmission time point and the 180 ° refocusing pulse transmission time point are calculated and controlled.

  Then, as shown in FIG. 2, the control unit 25 controls the data collection unit 24 to collect the first magnetic resonance signal MR1 obtained at the first echo time TE1 as the magnetic resonance signal MR. Further, the second magnetic resonance signal MR2 obtained at the second echo time TE2 shorter than the first echo time TE is controlled so that the data collecting unit 24 collects it as the magnetic resonance signal MR. Further, the third magnetic resonance signal MR3 obtained in the third echo signal TE3 longer than the first echo time TE1 so as to correspond to the difference value t between the first echo time TE1 and the second echo time TE2 is represented by data Control is performed so that the collecting unit 24 collects the magnetic resonance signal MR.

  Here, the control unit 25 calculates the second echo time TE2 and the third echo time TE3 based on the imaging conditions input to the operation unit 32 by the operator and the imaging conditions of the first echo time TE1, respectively. Control to correspond to.

  In the present embodiment, the second time shorter than the first echo time TE1 by the time Tout in which the magnetic resonance signal from the water of the subject 40 and the magnetic resonance signal from the fat of the subject 40 are in opposite phases. At the echo time TE2, the control unit 25 sets the second echo time TE2 so that the data collection unit 24 collects the second magnetic resonance signal MR2. That is, a time Tout in which magnetic resonance signals from the first tissue and the second tissue having different resonance frequencies, such as water and fat of the subject 40, are in opposite phases, the first echo time TE1, and the first echo time TE1. The second echo time TE2 is set so that the difference value t with the two echo times TE2 is the same. The time Tout (mSec) at which the magnetic resonance signals of water and fat are in opposite phases is the static magnetic field strength B0 (T), the rotational magnetic ratio γ (MHz / T), and a positive integer N (N = 1, 2). , 3..., Tout = {(2N−1) / 2} × 1000 / (3.5 · γ · B0). Therefore, based on this relational expression, for example, when the static magnetic field strength is 1.5T, the control unit 25 has a time shorter by 2.3 milliseconds than the first echo time TE1. A second echo time TE2 is set. Then, the control unit 25 causes the third echo time TE3 so that the data collecting unit 24 collects the third magnetic resonance signal MR3 obtained at the third echo time TE3 longer than the first echo time TE1. Set. Here, the first time Tout corresponding to the difference value t between the first echo time TE1 and the second echo time TE2, the time Tout corresponding to the respective phases of the magnetic resonance signals of water and fat of the subject 40 are reversed. The third echo time TE3 is set longer than the one echo time TE1. For example, when the static magnetic field strength is 1.5T, the third echo time TE3 is set so as to be 2.3 milliseconds longer than the first echo time TE1.

  Then, the control unit 25 controls the application of the RF pulse and the gradient magnetic field to the subject 40 for each TR based on the imaging conditions set as described above, and the magnetic force generated from the subject 40. The resonance signal is collected by the data collection unit 24. Here, as described above, the data collection unit 24 performs the first magnetic resonance signal MR1 obtained at the first echo time TE1, the second magnetic resonance signal MR2 obtained at the second echo time TE2, and the third echo time. Each of the third magnetic resonance signals MR3 obtained in TE3 is collected as a magnetic resonance signal MR.

  Next, the data processing unit 31 generates an image of the slice of the subject 40 based on the magnetic resonance signal MR collected by the data collecting unit 24. The data processing unit 31 performs a Fourier transform process on the magnetic resonance signal MR converted into a digital signal by the data collection unit 24 to generate an image of the subject 40.

  Here, the data processing unit 31 performs the first image I1, the second image I2, and the third image I3 based on the first magnetic resonance signal MR1, the second magnetic resonance signal MR2, and the third magnetic resonance signal MR3, respectively. Each is generated as an intensity image. That is, the data processing unit 31 generates the first image I1 based on the first magnetic resonance signal MR1, generates the second image I2 based on the second magnetic resonance signal MR2, and based on the third magnetic resonance signal MR3. The third image I3 is generated. Thereafter, the data processing unit 31 averages the second image I2 and the third image I3 to generate a fourth image I4. That is, the second image I2 and the third image I3 are configured such that each pixel is constituted by an average value of the pixel of the second image I2 and the pixel of the third image I3 corresponding to the pixel of the second image I2. A fourth image I4 is generated by averaging pixel values among the images.

  Next, the display unit 33 displays the first image I1 and the fourth image I4 generated by the data processing unit 31.

  FIG. 3 is a diagram showing the first image I1 and the fourth image I4 displayed by the display unit 33. As shown in FIG. FIG. 3 shows a first image I1 and a fourth image I4 that display the liver A, fat B, and other organs C in the subject 40.

  As shown in FIG. 3, the first image I1 corresponds to an image in which water and fat are in phase, so that the fat B portion is displayed with high luminance. On the other hand, since the fourth image I4 is generated by averaging the second image I2 and the third image I3 corresponding to the images in the case where water and fat are in opposite phases, the fat B portion has a low luminance. It is displayed as follows. Then, the display unit 33 displays the first image I1 and the fourth image I4 thus generated side by side.

  As described above, in the present embodiment, the first magnetic resonance signal MR1 obtained at the first echo time TE1, the second magnetic resonance signal MR2 obtained at the second echo time TE2 shorter than the first echo time TE1, Each of the third magnetic resonance signals MR3 obtained at the third echo time TE3 longer than the first echo time TE1 so as to correspond to the difference value between the first echo time TE1 and the second echo time TE2 is expressed as a magnetic resonance signal. As MR, the data collection part 24 collects by the spin echo method. Here, the data collection unit 24 collects the first magnetic resonance signal MR1 obtained at the first echo time TE1, which is twice the time interval τ between the transmission time of the 90 ° RF pulse and the transmission time of the 180 ° refocusing pulse. To do. Then, the data collection unit 24 outputs the second magnetic resonance signal MR2 at the second echo time TE2 that is shorter than the first echo time TE1 corresponding to the time Tout when the water and fat signals of the subject 40 are in opposite phases. collect. Then, the data collection unit 24 outputs the third magnetic resonance signal MR3 at a third echo time TE3 longer than the first echo time TE1 corresponding to the time Tout when the signals of water and fat of the subject 40 are in opposite phases. collect. Then, the data processing unit 31 generates the first image I1 based on the first magnetic resonance signal MR1, generates the second image I2 based on the second magnetic resonance signal MR2, and based on the third magnetic resonance signal MR3. The third image I3 is generated, and the second image I2 and the third image I3 are averaged to generate the fourth image I4. The display unit 33 displays the first image I1 as an image when water and fat are in phase, and displays the fourth image I4 as an image when water and fat are in opposite phases. For this reason, in the present embodiment, both an image in the case where the water and fat in the subject 40 are in phase and an image in the opposite phase are obtained with sufficient contrast. In particular, in the present embodiment, the second image I2 and the third image I3 have the same T2 * attenuation added to the first image I1 in the second image I2 and the third image I3. As with the first image I1, the fourth image I4 generated by averaging is reduced in the influence of T2 attenuation. Therefore, this embodiment can obtain an image with a sufficient contrast and can improve the image quality.

<Embodiment 2>
The magnetic resonance imaging apparatus according to the second embodiment of the present invention will be described below.

  In the magnetic resonance imaging apparatus of the present embodiment, the second echo time TE2 and the third echo time TE3 operate so as to be different from those in the first embodiment. In the present embodiment, the liver portion of the subject 40 to which SPIO (Super Paramagnetic Iron Oxide) is administered is imaged. Except for this point, the present embodiment is the same as the first embodiment. For this reason, description is abbreviate | omitted about the overlapping location.

  In the present embodiment, unlike the first embodiment, the control unit 25 is set to be longer than the first echo time TE1 by the time Tin during which the magnetic resonance signals from the water and fat of the subject 40 are in phase. The second echo time TE2 is set so as to be shorter. That is, the difference value t between the first echo time TE1 and the second echo time TE2 is set to be the same as the time Tin when the water and fat magnetic resonance signals of the subject 40 are in phase. The time Tin at which the magnetic resonance signals of water and fat each have the same phase depends on the static magnetic field strength B0, the rotational magnetic ratio γ, and a positive integer N (N = 1, 2, 3...). N / (3.5 · γ · B0). For this reason, the control unit 25 of the present embodiment, based on the above relational expression, for example, when the static magnetic field strength is 1.5T, a time shorter by 4.6 milliseconds than the first echo time TE1. The second echo time TE2 is set so that

  Then, the first resonance time TE1 and the second echo time TE2 correspond to the difference value t, and the first and second phases of the magnetic resonance signals of the water 40 and the fat of the subject 40 are in phase with each other. The third echo time TE3 is set so as to be longer than one echo time TE1. For example, when the static magnetic field strength is 1.5T, the third echo time TE3 is set to be 4.5 milliseconds longer than the first echo time TE1.

  Then, the control unit 25 controls the application of the RF pulse and the gradient magnetic field to the subject 40 for each TR based on the imaging conditions set as described above, and the magnetic force generated from the subject 40. The resonance signal MR is collected by the data collection unit 24. Here, as in the first embodiment, the data collection unit 24 includes the first magnetic resonance signal MR1 obtained at the first echo time TE1, the second magnetic resonance signal MR2 obtained at the second echo time TE2, and the third Each of the third magnetic resonance signal MR3 obtained at the echo time TE3 is collected as a magnetic resonance signal MR.

  Next, the data processing unit 31 generates an image of the slice of the subject 40 based on the magnetic resonance signal MR collected by the data collecting unit 24.

  Here, as in the first embodiment, the data processing unit 31 generates the first image I1 based on the first magnetic resonance signal MR1, and generates the second image I2 based on the second magnetic resonance signal MR2. A third image I3 is generated based on the third magnetic resonance signal MR3. After that, the data processing unit 31 generates the fourth image I4 by averaging the second image I2 and the third image I3 for each pixel.

  Next, the display unit 33 displays the first image I1 and the fourth image I4 generated by the data processing unit 31.

  FIG. 4 is a diagram showing the first image I1 and the fourth image I4 displayed by the display unit 33. As shown in FIG. In FIG. 4, a first image I1 and a fourth image I4 displaying the liver A, fat B, other organ C, and tumor D of the subject 40 are shown.

  As shown in FIG. 4, since the first image I1 corresponds to an image in the case where water and fat are in the same phase as in the first embodiment, the first image I1 is displayed so that the portion of fat B has high luminance. . On the other hand, the fourth image I4 is generated by averaging the second image I2 and the third image I3 corresponding to the images in the case where water and fat have the same phase, and thus is displayed as a T2 * emphasized image. . That is, in this embodiment, the portion of the liver A other than the tumor D is displayed so as to have a low luminance due to the influence of T2 * attenuation because SPIO is deposited. The tumor D is displayed so as not to attenuate because the SPIO is not deposited and to have a higher luminance than the liver A.

  As described above, in the present embodiment, the data collection unit 24 has the second echo time TE2 shorter than the first echo time TE1 corresponding to the time Tin when the water and fat signals of the subject 40 are in phase. Collects the second magnetic resonance signal MR2. Then, the data collection unit 24 outputs the third magnetic resonance signal MR3 at a third echo time TE3 longer than the first echo time TE1 corresponding to the time Tin when the water and fat signals of the subject 40 are in phase. collect. As in the first embodiment, the data processing unit 31 generates the first image I1 and the fourth image I4, and the display unit 33 displays the first image I1 and the fourth image I4. For this reason, the present embodiment generates an enhanced image for T2 * attenuation so as not to be affected by T2 attenuation, and a sufficient contrast is obtained, so that the image quality can be improved.

<Embodiment 3>
The magnetic resonance imaging apparatus according to the third embodiment of the present invention will be described below.

  In the magnetic resonance imaging apparatus of the present embodiment, the data processing unit 31 operates differently from the second embodiment. Except for this point, the present embodiment is the same as the second embodiment. For this reason, description is abbreviate | omitted about the overlapping location.

  In the present embodiment, as in the second embodiment, after the first magnetic resonance signal MR1, the second magnetic resonance signal MR2, and the third magnetic resonance signal MR3 are collected by the data collection 24, the data processing unit 31 performs the first image. I1 and the fourth image I4 are generated.

  In the present embodiment, unlike the second embodiment, the data processing unit 31 calculates the difference between the fourth image I4 and the first image I1 to generate the fifth image I5. That is, the fifth pixel I5 is generated by performing subtraction processing on the corresponding pixels between the fourth image I4 and the first image I1.

  Then, the display unit 33 displays the first image I1 and the fifth image I5 generated by the data processing unit 31.

  FIG. 5 is a diagram showing the first image I1 and the fifth image I5 displayed by the display unit 33. As shown in FIG. FIG. 5 shows a first image I1 and a fifth image I5 displaying the liver A, fat B, other organ C, and tumor D of the subject 40.

  As shown in FIG. 5, since the first image I1 corresponds to an image in the case where water and fat are in the same phase as in the second embodiment, the first image I1 is displayed so that the portion of fat B has high luminance. . On the other hand, since the fifth image is a difference image between the first image I1 and the fourth image I4, it is displayed as a T2 * emphasized image. That is, the tumor D is displayed to have a lower luminance than the liver A, contrary to the second embodiment.

  As described above, in this embodiment, after the data processing unit 31 generates the fifth image I5 that is a difference image between the first image I1 and the fourth image I4, the display unit 33 performs the first image I1 and the fifth image I5. The image I5 is displayed. For this reason, this embodiment can improve the image quality because an enhanced image for T2 * attenuation can be obtained with sufficient contrast, as in the second embodiment.

<Embodiment 4>
The magnetic resonance imaging apparatus according to the fourth embodiment of the present invention will be described below.

  In the magnetic resonance imaging apparatus of the present embodiment, the control unit 25 operates differently from the first embodiment. Except for this point, the present embodiment is the same as the first embodiment. For this reason, description is abbreviate | omitted about the overlapping location.

  FIG. 6 is a pulse sequence diagram illustrating a procedure in which the control unit 25 controls each unit in 1TR. FIG. 6 shows an RF pulse RF, a gradient magnetic field Gr in the frequency encoding direction, and a magnetic resonance signal MR. In FIG. 6, two types of pulse sequences having different gradient magnetic fields Gr in the frequency encoding direction are shown side by side so as to correspond to the time axis, and the gradient magnetic field Gr1 in the frequency encoding direction corresponding to the first pulse sequence is shown. And the first magnetic resonance signal MR1 collected in this case, the gradient magnetic field Gr2 in the frequency encoding direction corresponding to the second pulse sequence, and the second magnetic resonance signal MR2 collected in this case. ing. Note that the gradient magnetic field Gs in the slice selection direction and the gradient magnetic field Gp in the phase encoding direction are the same as in the first embodiment.

  In the present embodiment, as illustrated in FIG. 6, the control unit 25 controls each unit so that an image of the subject 40 is captured by the first pulse sequence and the second pulse sequence based on the spin echo method.

  First, the control unit 25 controls each unit to capture an image of the subject 40 so as to correspond to the first pulse sequence. Thereafter, the control unit 25 controls each unit to capture an image of the subject 40 so as to correspond to the second pulse sequence.

  When performing the first pulse sequence, as shown in FIG. 6, the control unit 25 causes the data collection unit 24 to collect the first magnetic resonance signal MR1 obtained at the first echo time TE1 as the magnetic resonance signal MR. Control. Here, the data collection unit 24 collects the first magnetic resonance signal MR1 obtained at the first echo time TE1, which is twice the time interval τ between the transmission time of the 90 ° RF pulse and the transmission time of the 180 ° refocusing pulse. Control to do.

  When the second pulse sequence is performed, the data collection unit 24 collects the second magnetic resonance signal MR2 obtained at the second echo time TE2 longer than the first echo time TE as the magnetic resonance signal MR. To control. Here, as in the first embodiment, the control unit 25 calculates and controls the second echo time TE2 based on the imaging condition of the imaging method input to the operation unit 32 by the operator and the first echo time TE1. . In the present embodiment, a time longer than the first echo time TE1 by a time Tout in which the magnetic resonance signal from the water of the subject 40 and the magnetic resonance signal from the fat of the subject 40 are in opposite phases. The control unit 25 sets the second echo time TE2 so that the data collection unit 24 collects the second magnetic resonance signal MR2 at the two echo time TE2. For example, when the static magnetic field strength is 1.5T, the second echo time TE2 is set so as to be 2.3 milliseconds longer than the first echo time TE1.

  Then, based on the imaging conditions set as described above, the control unit 25 controls the subject 40 to apply the RF pulse and the gradient magnetic field for each TR, and magnetic resonance generated from the subject 40. The signal is collected by the data collecting unit 24. That is, the data collection unit 24 collects the first magnetic resonance signal MR1 obtained at the first echo time TE1 and the second magnetic resonance signal MR2 obtained at the second echo time TE2 as the magnetic resonance signal MR.

  Next, the data processing unit 31 generates an image of the slice of the subject 40 based on the magnetic resonance signal MR collected by the data collecting unit 24. Here, the data processing unit 31 performs a Fourier transform process on the magnetic resonance signal MR converted into a digital signal by the data acquisition unit 24 to generate an image of the subject 40. Specifically, based on the first magnetic resonance signal MR1 and the second magnetic resonance signal MR2, the data processing unit 31 generates the first image I1 and the second image I2 as intensity images. That is, the data processing unit 31 generates the first image I1 based on the first magnetic resonance signal MR1, and generates the second image I2 based on the second magnetic resonance signal MR2.

  Next, the display unit 33 displays the first image I1 and the second image I2 generated by the data processing unit 31.

  FIG. 7 is a diagram showing the first image I1 and the second image I2 displayed by the display unit 33. As shown in FIG. FIG. 7 shows a first image I1 and a second image I2 that display the liver A, fat B, and other organs C in the subject 40.

  As shown in FIG. 7, the first image I1 corresponds to an image in the case where water and fat are in phase, so that the fat B portion is displayed with high luminance. On the other hand, since the second image I2 corresponds to an image in which water and fat are in opposite phases, the fat B portion is displayed with low luminance.

  As described above, in the present embodiment, each of the first magnetic resonance signal MR1 obtained at the first echo time TE1 and the second magnetic resonance signal MR2 obtained at the second echo time TE2 different from the first echo time TE1. Is collected as a magnetic resonance signal MR by the data collection unit 24 by a spin echo method. Here, the data collection unit 24 collects the first magnetic resonance signal MR1 obtained at the first echo time TE1, which is twice the time interval τ between the transmission time of the 90 ° RF pulse and the transmission time of the 180 ° refocusing pulse. To do. Then, the data collection unit 24 outputs the second magnetic resonance signal MR2 at the second echo time TE2 longer than the first echo time TE1 corresponding to the time Tout in which the water and fat signals of the subject 40 are in opposite phases. collect. Then, the data processing unit 31 generates the first image I1 based on the first magnetic resonance signal MR1, and generates the second image I2 based on the second magnetic resonance signal MR2. The display unit 33 displays the first image I1 as an image when water and fat are in the same phase, and displays the second image I2 as an image when water and fat are in opposite phases. Thus, since this embodiment images the 1st image I1 so that there is no influence of T2 * attenuation using the magnetic resonance signal collected after the phase was rewound by the spin echo method, Both the first image I1 when the water and the fat in the subject 40 are in phase and the second image I2 when the phase is opposite to each other can be obtained with sufficient contrast, and the image quality can be improved. it can.

<Embodiment 5>
The magnetic resonance imaging apparatus according to the fifth embodiment of the present invention will be described below.

  In the magnetic resonance imaging apparatus of the present embodiment, the second echo time TE2 operates so as to be different from that of the fourth embodiment. In the present embodiment, as in the second embodiment, the liver portion of the subject 40 to which SPIO has been administered is imaged. Except for this point, the present embodiment is the same as the fourth embodiment. For this reason, description is abbreviate | omitted about the overlapping location.

  In the present embodiment, unlike the fourth embodiment, the control unit 25 is set to be longer than the first echo time TE1 by the amount of time Tin when the magnetic resonance signals from the water and fat of the subject 40 are in phase. The second echo time TE2 is set to be longer. That is, the difference value t between the first echo time TE1 and the second echo time TE2 is set to be the same as the time Tin when the water and fat magnetic resonance signals of the subject 40 are in phase. For example, when the static magnetic field strength is 1.5T, the second echo time TE2 is set so as to be 4.6 milliseconds longer than the first echo time TE1.

  Then, the control unit 25 controls the application of the RF pulse and the gradient magnetic field to the subject 40 for each TR based on the imaging conditions set as described above, and the magnetic force generated from the subject 40. The resonance signal MR is collected by the data collection unit 24. Here, as in the fourth embodiment, the data collection unit 24 calculates the first magnetic resonance signal MR1 obtained at the first echo time TE1 and the second magnetic resonance signal MR2 obtained at the second echo time TE2. Collected as a magnetic resonance signal MR.

  Next, the data processing unit 31 generates an image of the slice of the subject 40 based on the magnetic resonance signal MR collected by the data collecting unit 24.

  Here, as in the fourth embodiment, the data processing unit 31 generates the first image I1 based on the first magnetic resonance signal MR1, and generates the second image I2 based on the second magnetic resonance signal MR2.

  Next, the display unit 33 displays the first image I1 and the second image I2 generated by the data processing unit 31.

  FIG. 8 is a diagram showing the first image I1 and the second image I2 displayed by the display unit 33. As shown in FIG. FIG. 8 shows a first image I1 and a second image I2 that display the liver A, fat B, other organ C, and tumor D of the subject 40.

  As shown in FIG. 8, since the first image I1 corresponds to an image in the case where water and fat are in the same phase as in the fourth embodiment, the first image I1 is displayed so that the fat B portion has high luminance. . On the other hand, the second image I2 is displayed as a T2 * emphasized image. That is, in this embodiment, as in the second embodiment, the portion of the liver A other than the tumor D is displayed so as to have a low luminance due to the influence of T2 * attenuation because the SPIO is deposited. The tumor D is displayed so as not to attenuate because the SPIO is not deposited and to have a higher brightness than the liver A.

  As described above, in the present embodiment, the data collection unit 24 has the second echo time TE2 longer than the first echo time TE1 corresponding to the time Tin when the water and fat signals of the subject 40 are in phase. A second magnetic resonance signal MR2 is collected. As in the fourth embodiment, the data processing unit 31 generates the first image I1 and the second image I2, and the display unit 33 displays the first image I1 and the second image I2. For this reason, since the emphasis image about T2 * attenuation is obtained with sufficient contrast, this embodiment can improve image quality.

<Embodiment 6>
The magnetic resonance imaging apparatus according to the sixth embodiment of the present invention will be described below.

  In the magnetic resonance imaging apparatus of the present embodiment, the data processing unit 31 operates differently from the fifth embodiment. Except for this point, the present embodiment is the same as the fifth embodiment. For this reason, description is abbreviate | omitted about the overlapping location.

  In the present embodiment, as in the fifth embodiment, after the data collection 24 collects the first magnetic resonance signal MR1 and the second magnetic resonance signal MR2, the data processing unit 31 executes the first image I1 and the second image I2. Is generated.

  In this embodiment, unlike the fifth embodiment, the data processing unit 31 calculates the difference between the second image I2 and the first image I1 to generate the third image I3.

  Then, the display unit 33 displays the first image I1 and the third image I3 generated by the data processing unit 31.

  FIG. 9 is a diagram showing the first image I1 and the third image I3 displayed by the display unit 33. As shown in FIG. FIG. 5 shows a first image I1 and a third image I3 displaying the liver A, fat B, other organ C, and tumor D of the subject 40.

  As shown in FIG. 9, since the first image I1 corresponds to an image in the case where water and fat are in the same phase as in the fifth embodiment, the first image I1 is displayed so that the portion of fat B has high luminance. . On the other hand, since the third image I3 is a difference image between the first image I1 and the second image I2, it is displayed as a T2 * emphasized image. That is, the tumor D is displayed to have a lower luminance than the liver A, contrary to the fifth embodiment.

  As described above, in the present embodiment, after the data processing unit 31 generates the third image I3 that is a difference image between the first image I1 and the second image I2, the display unit 33 performs the first image I1 and the third image I3. The image I3 is displayed. For this reason, this embodiment can improve the image quality because an enhanced image for T2 * attenuation can be obtained with sufficient contrast, as in the fifth embodiment.

<Embodiment 7>
The magnetic resonance imaging apparatus according to the seventh embodiment of the present invention will be described below.

  In the magnetic resonance imaging apparatus of the present embodiment, the control unit 25 operates differently from the fourth embodiment. Except for this point, the present embodiment is the same as the fourth embodiment. For this reason, description is abbreviate | omitted about the overlapping location.

  FIG. 10 is a pulse sequence diagram illustrating a procedure in which the control unit 25 controls each unit in 1TR. FIG. 10 shows an RF pulse RF, a gradient magnetic field Gr in the frequency encoding direction, and a magnetic resonance signal MR. In FIG. 10, two types of pulse sequences having different RF pulses RF are shown side by side so as to correspond to the time axis, and the RF pulse RF1 corresponding to the first pulse sequence and collected in this case The first magnetic resonance signal MR1 is shown, and the RF pulse RF2 corresponding to the second pulse sequence and the second magnetic resonance signal MR2 collected in this case are shown. Note that the gradient magnetic field Gs in the slice selection direction and the gradient magnetic field Gp in the phase encoding direction are the same as in the first embodiment.

  In the present embodiment, as illustrated in FIG. 6, the control unit 25 controls each unit so that an image of the subject 40 is captured by the first pulse sequence and the second pulse sequence based on the spin echo method.

  First, the control unit 25 controls each unit to capture an image of the subject 40 so as to correspond to the first pulse sequence. Thereafter, the control unit 25 controls each unit to capture an image of the subject 40 so as to correspond to the second pulse sequence.

  In performing the first pulse sequence, as shown in FIG. 10, the 90 ° RF pulse is transmitted to the subject to the RF coil unit 14 and 180 ° after the first time τ 1 has elapsed from the 90 ° RF pulse. After the refocusing pulse is transmitted to the subject through the RF coil unit 14, the first magnetic resonance signal MR1 obtained at the echo time TE after the elapse of the first time τ1 from the 180 ° refocusing pulse is obtained as the data collecting unit 24. Is collected as a magnetic resonance signal MR. That is, in order to collect the first magnetic resonance signal MR1 at the spin echo timing, it is twice the first time τ1, which is the time interval between the transmission time of the 90 ° RF pulse and the transmission time of the 180 ° refocusing pulse. Control is performed so that the data collection unit 24 collects the first magnetic resonance signal MR1 obtained at the echo time TE.

  When performing the second pulse sequence, as shown in FIG. 10, the 90 ° RF pulse is transmitted to the subject to the RF coil unit 14, and the 90 ° RF pulse is different from the first time τ1 from the 90 ° RF pulse. The second magnetic resonance signal obtained at the same echo time TE as the echo time TE at which the first magnetic resonance signal was collected after the 180 ° refocusing pulse was transmitted to the subject by the RF coil unit 14 after the elapse of 2 hours τ2. The MR 2 is controlled so that the data collecting unit 24 collects it as a magnetic resonance signal. That is, control is performed so that the second magnetic resonance signal MR2 is collected at a timing deviating from the spin echo timing. Here, based on the imaging condition of the imaging method and the echo time TE input to the operation unit 32 by the operator, the control unit 25 transmits the 90 ° RF pulse transmission time and the 180 ° refocus pulse in the second pulse sequence. A second time τ2, which is a time interval from the transmission time, is calculated and controlled. In the present embodiment, in the first pulse sequence, a short second time τ2 is obtained by a predetermined time dτ from the first time τ1, which is the time interval between the transmission time of the 90 ° RF pulse and the transmission time of the 180 ° refocus pulse. In the second pulse sequence, the control unit 25 controls the data collection unit 24 so as to collect the second magnetic resonance signal MR2.

  Then, based on the imaging conditions set as described above, the control unit 25 controls the subject 40 to apply the RF pulse and the gradient magnetic field for each TR, and magnetic resonance generated from the subject 40. The signal is collected by the data collecting unit 24. That is, the data collection unit 24 collects each of the first magnetic resonance signal MR1 obtained in the first pulse sequence and the second magnetic resonance signal MR2 obtained in the second pulse sequence as the magnetic resonance signal MR.

  Next, the data processing unit 31 generates an image of the slice of the subject 40 based on the magnetic resonance signal MR collected by the data collecting unit 24. Here, as in the fourth embodiment, the data processing unit 31 performs a Fourier transform process on the magnetic resonance signal MR converted into a digital signal by the data collection unit 24 to generate an image of the subject 40. Specifically, based on the first magnetic resonance signal MR1 and the second magnetic resonance signal MR2, the data processing unit 31 generates the first image I1 and the second image I2 as intensity images. That is, the data processing unit 31 generates the first image I1 based on the first magnetic resonance signal MR1, and generates the second image I2 based on the second magnetic resonance signal MR2.

  Next, the display unit 33 displays the first image I1 and the second image I2 generated by the data processing unit 31.

  Note that, similarly to the fifth and sixth embodiments, the present invention is also applicable to the case where an image is generated and displayed.

  As described above, in the present embodiment, a 90 ° RF pulse is transmitted to the subject by the spin echo method, and a 180 ° refocusing pulse is transmitted to the subject after the first time τ1 has elapsed from the 90 ° RF pulse. After that, the data collection unit 24 collects the first magnetic resonance signal MR1 obtained at the echo time TE after the lapse of the first time τ1 from the 180 ° refocusing pulse. Further, a 90 ° RF pulse is transmitted to the subject by spin echo method, and a 180 ° refocusing pulse is transmitted to the subject after a lapse of a second time τ2 shorter than the first time τ1 from the 90 ° RF pulse. Later, the data collection unit 24 collects the second magnetic resonance signal MR2 obtained at the same echo time TE as the echo time TE from which the first magnetic resonance signal MR1 was collected. Then, the data processing unit 31 generates the first image I1 based on the first magnetic resonance signal MR1, and generates the second image I2 based on the second magnetic resonance signal MR2. The display unit 33 displays the first image I1 and the second image I2. Thus, this embodiment uses the magnetic resonance signal collected after the phase is rewound by the spin echo method in the first pulse sequence, and the first image I1 is not affected by T2 * attenuation. Since the imaging is performed, it is possible to generate the first image I1 when water and fat in the subject 40 have the same phase. On the other hand, in the second pulse sequence, the influence of T2 * attenuation is added unlike the first image I1 by changing the transmission timing of the 180 ° refocusing pulse with respect to the first pulse sequence. By making the sequence and the echo time TE the same, it is possible to generate the second image I2 in which the influence of T2 attenuation is the same as that of the first image I1. Therefore, in the present embodiment, both the first image I1 and the second image I2 can be obtained with sufficient contrast, and the image quality can be improved and the diagnostic efficiency can be improved.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be employed.

  FIG. 11 is a pulse sequence diagram illustrating a procedure in which the control unit 25 controls each unit in 1TR in a modification of the present invention. FIG. 11 shows an RF pulse RF and a gradient magnetic field Gr in the frequency encoding direction. Note that the description of the gradient magnetic field Gs in the slice selection direction and the gradient magnetic field Gp in the phase encoding direction is omitted.

  For example, as shown in FIG. 11A, the first echo time TE1 is acquired so that each of the first magnetic resonance signal MR1 and the second magnetic resonance signal MR2 in the fourth to sixth embodiments is collected in the same TR. And the second echo time TE2 may be set to image the subject. Specifically, the subject may be imaged by setting the second echo time TE2 to be longer than the first echo time TE1.

  Also, for example, as shown in FIG. 11 (b), contrary to FIG. 11 (a), the second echo time TE2 is set to be shorter than the first echo time TE1, and the subject is imaged. Also good.

  Further, for example, as shown in FIG. 11C, gradient magnetic field lobes may be applied to the first to third embodiments based on the flow rate correction method (Flow Compensation). FIG. 11C shows a case where a gradient magnetic field lobe is added in the frequency encoding direction so as to correspond to a primary flow, that is, a constant velocity flow. In the fourth to seventh embodiments, similarly, gradient magnetic field lobes may be applied based on the flow velocity correction method.

  For example, as shown in FIG. 11 (d), the application of the gradient magnetic field Gr in the frequency encoding direction in the first to third embodiments may be applied to the gradient echo method to image the subject.

  In addition, in the present invention, the reception frequency is not limited, and the reception frequency may be changed in the first echo time TE1, the second echo time TE2, and the third echo time TE3. Further, the bandwidth may be adjusted so that the S / N ratio is the same at the first echo time TE1, the second echo time TE2, and the third echo time TE3.

  In the above description, the case of collecting magnetic resonance signals corresponding to three echo times is shown, but the present invention is not limited to this, and may be four or more. In order to suppress the influence of the body movement of the subject, the magnetic resonance signal is collected in a state where the breath is held, or the magnetic resonance signal is collected so as to be synchronized with the heartbeat or breathing. Good. Further, a fast spin echo method may be applied. It may be applied to the case of T2 weighting or proton density weighting.

FIG. 1 is a configuration diagram showing the configuration of the magnetic resonance imaging apparatus according to the first embodiment of the present invention. FIG. 2 is a pulse sequence diagram illustrating a procedure in which the control unit controls each unit in 1TR in the first embodiment according to the present invention. FIG. 3 is a diagram illustrating a first image and a fourth image displayed by the display unit in the first embodiment according to the present invention. FIG. 4 is a diagram showing a first image and a fourth image displayed by the display unit in the second embodiment according to the present invention. FIG. 5 is a diagram illustrating a first image and a fifth image displayed by the display unit in the third embodiment according to the present invention. FIG. 6 is a pulse sequence diagram illustrating a procedure in which the control unit controls each unit in 1TR in the fourth embodiment according to the present invention. FIG. 7 is a diagram showing a first image and a second image displayed by the display unit in the fourth embodiment according to the present invention. FIG. 8 is a diagram showing a first image and a second image displayed by the display unit in the fifth embodiment according to the present invention. FIG. 9 is a diagram showing a first image and a second image displayed by the display unit in the sixth embodiment according to the present invention. FIG. 10 is a pulse sequence diagram illustrating a procedure in which the control unit controls each unit in 1TR in the seventh embodiment according to the present invention. FIG. 11 is a pulse sequence diagram illustrating a procedure in which the control unit controls each unit in 1TR in a modification according to the present invention.

Explanation of symbols

11: imaging space,
12: Static magnetic field magnet section,
13: Gradient coil part (gradient magnetic field application part),
14: RF coil part (transmission part),
22: RF drive unit,
23: Gradient drive unit,
24: Data collection unit (data collection unit),
25: Control unit,
26: Cradle,
31: Data processing unit (image generation unit),
32: Operation unit,
33: Display unit (display unit)

Claims (19)

A transmitter for transmitting an RF pulse to a subject in a static magnetic field and exciting the spin of the subject;
A gradient magnetic field applying unit that applies a gradient magnetic field to the subject and encodes a magnetic resonance signal from a spin excited by the RF pulse;
A data collection unit for collecting the magnetic resonance signal encoded by the gradient magnetic field;
An image generation unit that generates an image of the subject based on the magnetic resonance signals collected by the data collection unit,
The data collection unit
A difference between the first magnetic resonance signal obtained at the first echo time, the second magnetic resonance signal obtained at the second echo time shorter than the first echo time, and the first echo time and the second echo time. A magnetic resonance imaging apparatus that collects each of the third magnetic resonance signals obtained at a third echo time longer than the first echo time so as to correspond to the value as the magnetic resonance signal. A display unit for displaying an image generated by the image generation unit;
The image generation unit generates a first image based on the first magnetic resonance signal, generates a second image based on the second magnetic resonance signal, and generates a third image based on the third magnetic resonance signal. And generating a fourth image by averaging the second image and the third image,
The magnetic resonance imaging apparatus according to claim 1, wherein the display unit displays the first image and the fourth image. The data collection unit includes a second echo shorter than the first echo time so as to correspond to a time in which the magnetic resonance signal from the water of the subject and the magnetic resonance signal from the fat of the subject are in opposite phases. The magnetic resonance imaging apparatus according to claim 2, wherein the second magnetic resonance signal is collected over time. The data collection unit includes a second echo shorter than the first echo time so as to correspond to a time when the magnetic resonance signal from the water of the subject and the magnetic resonance signal from the fat of the subject are in phase. The magnetic resonance imaging apparatus according to claim 2, wherein the second magnetic resonance signal is collected over time. A display unit for displaying an image generated by the image generation unit;
The image generation unit generates a first image based on the first magnetic resonance signal, generates a second image based on the second magnetic resonance signal, and generates a third image based on the third magnetic resonance signal. And generating a fourth image by averaging the second image and the third image, and then calculating a difference between the fourth image and the first image to generate a fifth image. And
The magnetic resonance imaging apparatus according to claim 1, wherein the display unit displays the first image and the fifth image. The data collection unit includes a second echo shorter than the first echo time so as to correspond to a time when the magnetic resonance signal from the water of the subject and the magnetic resonance signal from the fat of the subject are in phase. The magnetic resonance imaging apparatus according to claim 5, wherein the second magnetic resonance signal is collected over time. The magnetic resonance unit according to claim 1, wherein the data collection unit collects each of the first magnetic resonance signal, the second magnetic resonance signal, and the third magnetic resonance signal within the same repetition time. Imaging device. The magnetic resonance imaging apparatus according to claim 1, wherein the data collection unit collects the magnetic resonance signal obtained by a spin echo method. The transmitter transmits an RF pulse for exciting the spin of the subject to the subject, and then transmits a refocusing pulse for refocusing the spin excited by the RF pulse and phase-dispersed to the subject. ,
The said data acquisition part collects the 1st magnetic resonance signal acquired in the said 1st echo time which becomes twice the time interval of the transmission time of the said RF pulse and the transmission time of the said refocusing pulse. Magnetic resonance imaging equipment. The magnetic resonance imaging apparatus according to claim 1, wherein the data collection unit collects the magnetic resonance signal obtained by a gradient echo method. A transmitter for transmitting an RF pulse to a subject in a static magnetic field and exciting the spin of the subject;
A gradient magnetic field applying unit that applies a gradient magnetic field to the subject and encodes a magnetic resonance signal from a spin excited by the RF pulse;
A data collection unit for collecting the magnetic resonance signal encoded by the gradient magnetic field;
An image generation unit that generates an image of the subject based on the magnetic resonance signals collected by the data collection unit,
The data collection unit
A first magnetic resonance signal obtained at a first echo time and a second magnetic resonance signal obtained at a second echo time different from the first echo time are collected as the magnetic resonance signal by a spin echo method. Resonance imaging device. A display unit for displaying an image generated by the image generation unit;
The image generation unit generates a first image based on the first magnetic resonance signal, generates a second image based on the second magnetic resonance signal,
The magnetic resonance imaging apparatus according to claim 11, wherein the display unit displays the first image and the second image. The data collection unit includes a second echo shorter than the first echo time so as to correspond to a time in which the magnetic resonance signal from the water of the subject and the magnetic resonance signal from the fat of the subject are in opposite phases. The magnetic resonance imaging apparatus according to claim 12, wherein the second magnetic resonance signal is collected over time. The data collection unit includes a second echo shorter than the first echo time so as to correspond to a time when the magnetic resonance signal from the water of the subject and the magnetic resonance signal from the fat of the subject are in phase. The magnetic resonance imaging apparatus according to claim 12, wherein the second magnetic resonance signal is collected over time. A display unit for displaying an image generated by the image generation unit;
The image generation unit generates a first image based on the first magnetic resonance signal, generates a second image based on the second magnetic resonance signal, and outputs the first image and the second image. Calculate the difference to generate the third image,
The magnetic resonance imaging apparatus according to claim 11, wherein the display unit displays the first image and the third image. The data collection unit includes a second echo shorter than the first echo time so as to correspond to a time when the magnetic resonance signal from the water of the subject and the magnetic resonance signal from the fat of the subject are in phase. The magnetic resonance imaging apparatus according to claim 15, wherein the second magnetic resonance signal is collected over time. The magnetic resonance imaging apparatus according to claim 11, wherein the data collection unit collects each of the first magnetic resonance signal and the second magnetic resonance signal within the same repetition time. The transmitter transmits an RF pulse for exciting the spin of the subject to the subject, and then transmits a refocusing pulse for refocusing the spin excited by the RF pulse and phase-dispersed to the subject. ,
The data collection unit collects a first magnetic resonance signal obtained at the first echo time that is twice the time interval between the transmission time of the RF pulse and the transmission time of the refocusing pulse. A magnetic resonance imaging apparatus according to any one of the above. A transmitter for transmitting an RF pulse to a subject in a static magnetic field and exciting the spin of the subject;
A gradient magnetic field applying unit that applies a gradient magnetic field to the subject and encodes a magnetic resonance signal from a spin excited by the RF pulse;
A data collection unit for collecting the magnetic resonance signal encoded by the gradient magnetic field;
An image generation unit that generates an image of the subject based on the magnetic resonance signals collected by the data collection unit,
The data collection unit
Using a spin echo method, a 90 ° RF pulse was transmitted to the subject by the transmitter, and a 180 ° refocusing pulse was transmitted to the subject by the transmitter after a lapse of a first time from the 90 ° RF pulse. Later, a 90 ° RF pulse is transmitted to the subject by the first magnetic resonance signal obtained at an echo time after the first time has elapsed from the 180 ° refocusing pulse and the spin echo method, and the subject is transmitted. After the 90 ° RF pulse has passed a second time different from the first time, the same time as the echo time at which the first magnetic resonance signal was collected after the 180 ° refocusing pulse was transmitted to the subject by the transmitter. A magnetic resonance imaging apparatus that collects each of the second magnetic resonance signals obtained at the echo time as the magnetic resonance signal.

Images