Magnetic resonance data acquisition apparatus, magnetic resonance data acquisition method, and magnetic resonance data acquisition program

Abstract

To accurately reduce the influence of a fat signal on a spectrum while reducing dependence on an operator.SOLUTION: A magnetic resonance data collection device includes an acquisition unit, a generation unit, and a collection unit. The acquisition unit acquires a designated region of interest. The generating unit generates a pulse sequence for acquiring magnetic resonance data a plurality of times while changing at least one of an acquisition region and a setting condition of a saturation pulse with reference to the region of interest. The collection part collects a plurality of magnetic resonance data according to the pulse sequence.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The embodiments disclosed in this specification and the drawings relate to a magnetic resonance data acquisition device, a magnetic resonance data acquisition method, and a magnetic resonance data acquisition program. [Background technology]

[0002] When collecting magnetic resonance spectroscopy signals, analysis becomes difficult if fat signals are mixed in. Therefore, methods such as suppressing the fat signal band using saturation pulses, suppressing areas where fat is likely to exist using saturation pulses, or adjusting the volume of interest (VOI) to exclude areas where fat is likely to exist from the VOI can be considered. However, in the method of suppressing the fat signal band using a saturation pulse, the suppression affects not only the fat signal but also the spectrum of the desired metabolite signal. Furthermore, the method of suppressing the region where fat is likely to exist or the method of adjusting the VOI to remove it from the VOI requires manual fine-tuning, which causes the problem of variation in accuracy depending on the experience and ability of the operator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-187038 Summary of the Invention [Problem to be solved by the invention]

[0004] One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to accurately reduce the influence of fat signals on the spectrum while reducing dependency on the operator. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described below can also be positioned as other problems. [Means for solving the problem]

[0005] The magnetic resonance data acquisition apparatus according to this embodiment includes an acquisition unit, a generation unit, and an acquisition unit. The acquisition unit acquires a designated region of interest. The generation unit generates a pulse sequence for acquiring magnetic resonance data multiple times while changing at least one of an acquisition region and a setting condition of a saturation pulse based on the region of interest. The acquisition unit acquires multiple pieces of magnetic resonance data in accordance with the pulse sequence. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a block diagram showing a magnetic resonance data acquisition apparatus according to this embodiment. [Figure 2] FIG. 2 is a flowchart showing an example of the operation of the magnetic resonance data acquisition device. [Figure 3] FIG. 3 is a flowchart showing a detailed example of the operation of the magnetic resonance data acquisition device in the case of an acquisition method including the first technique. [Figure 4] FIG. 4 is a diagram showing an example of setting a region of interest according to the first method. [Figure 5] FIG. 5 is a flowchart showing a detailed example of the operation of the magnetic resonance data acquisition device in the case of an acquisition method including the second technique. [Figure 6] FIG. 6 is a diagram showing an example of setting a change pattern of saturation pulses according to the second method. [Figure 7] FIG. 7 is a diagram showing an example of displaying the spectra of a plurality of MRS signals based on the acquisition method according to the first technique. [Figure 8]FIG. 8 is a diagram showing an example of displaying the spectra of a plurality of MRS signals based on the acquisition method according to the second technique. DETAILED DESCRIPTION OF THE INVENTION

[0007] The magnetic resonance data acquisition device, magnetic resonance data acquisition method, and magnetic resonance data acquisition program according to the present embodiment will be described below with reference to the drawings. In the following embodiments, parts with the same reference numerals perform similar operations, and redundant explanations will be omitted as appropriate. One embodiment will be described below with reference to the drawings.

[0008] Fig. 1 is a block diagram showing an example of the configuration of a magnetic resonance data acquisition device according to this embodiment. As shown in Fig. 1, the magnetic resonance data acquisition device 1 is, for example, a magnetic resonance imaging device. It includes a gantry 11, a bed 13, a gradient magnetic field power supply 21, a transmission circuit 23, a reception circuit 25, a bed driving device 27, a sequence control circuit 29, and a medical information processing device (host computer) 50.

[0009] The gantry 11 has a static magnetic field magnet 41 and a gradient magnetic field coil 43. The static magnetic field magnet 41 and the gradient magnetic field coil 43 are housed in a housing of the gantry 11. A hollow bore is formed in the housing of the gantry 11. A transmitting coil 45 and a receiving coil 47 are arranged in the bore of the gantry 11.

[0010] The static magnetic field magnet 41 has a hollow, approximately cylindrical shape and generates a static magnetic field inside the approximately cylinder. For example, a permanent magnet, a superconducting magnet, or a normal-conducting magnet may be used as the static magnetic field magnet 41. Here, the central axis of the static magnetic field magnet 41 is defined as the Z axis, the axis perpendicular to the Z axis is defined as the Y axis, and the axis horizontally perpendicular to the Z axis is defined as the X axis. The X axis, Y axis, and Z axis form an orthogonal three-dimensional coordinate system.

[0011] The gradient coil 43 is a hollow, approximately cylindrical coil unit attached to the inside of the static magnetic field magnet 41. The gradient coil 43 generates a gradient magnetic field by receiving a current from the gradient power supply 21. More specifically, the gradient coil 43 has three coils corresponding to the X-axis, Y-axis, and Z-axis, which are orthogonal to each other. The three coils form gradient magnetic fields whose field strength varies along each of the X-axis, Y-axis, and Z-axis. The gradient magnetic fields along the X-axis, Y-axis, and Z-axis are combined to form a frequency encoding gradient magnetic field Gr, a phase encoding gradient magnetic field Gp, and a slice selection gradient magnetic field Gs, which are orthogonal to each other, in desired directions. The frequency encoding gradient magnetic field Gr is used to change the frequency of a magnetic resonance signal (hereinafter referred to as an MR signal) according to a spatial position. The phase encoding gradient magnetic field Gp is ​​used to change the phase of the MR signal according to a spatial position. The slice selection gradient magnetic field Gs is used to arbitrarily determine an imaging plane (slice). In the following description, the gradient direction of the frequency encoding gradient magnetic field Gr is the X axis, the gradient direction of the phase encoding gradient magnetic field Gp is ​​the Y axis, and the gradient direction of the slice selection gradient magnetic field Gs is the Z axis.

[0012] The gradient magnetic field power supply 21 supplies a current to the gradient magnetic field coil 43 in accordance with a sequence control signal from the sequence control circuit 29. The gradient magnetic field power supply 21 supplies a current to the gradient magnetic field coil 43, thereby causing the gradient magnetic field coil 43 to generate gradient magnetic fields along the X-axis, Y-axis, and Z-axis. The gradient magnetic fields are superimposed on the static magnetic field formed by the static magnetic field magnet 41 and applied to the subject P.

[0013] The transmission coil 45 is disposed, for example, inside the gradient magnetic field coil 43, and receives a current from the transmission circuit 23 to generate a radio frequency pulse (hereinafter referred to as an RF pulse).

[0014] The transmission circuitry 23 supplies a current to the transmission coil 45 to apply an RF pulse to the subject P via the transmission coil 45 to excite target protons present in the subject P. The RF pulse oscillates at a resonance frequency specific to the target protons, exciting the target protons. An MR signal is generated from the excited target protons and detected by the reception coil 47. The transmission coil 45 is, for example, a whole-body coil (WB coil). The whole-body coil may be used as a transmission / reception coil.

[0015] The receive coil 47 receives MR signals emitted from target protons present in the subject P in response to the action of RF pulses. The receive coil 47 has multiple receive coil elements capable of receiving MR signals. The received MR signals are supplied to the receiver circuit 25 via wire or wirelessly. Although not shown in FIG. 1 , the receive coil 47 has multiple receive channels implemented in parallel. Each receive channel has receive coil elements that receive MR signals and amplifiers that amplify the MR signals. MR signals are output for each receive channel. The total number of receive channels and the total number of receive coil elements may be the same, or the total number of receive channels may be greater or less than the total number of receive coil elements.

[0016] The receiving circuitry 25 receives MR signals generated from the excited target protons via the receiving coil 47. The receiving circuitry 25 processes the received MR signals to generate digital MR signals. The digital MR signals can be expressed in k-space defined by spatial frequencies. Therefore, hereinafter, the digital MR signals will be referred to as k-space data. The k-space data is an example of an MR acquisition signal. The k-space data is supplied to the medical information processing device 50 via a wired or wireless connection.

[0017] The above-described transmitting coil 45 and receiving coil 47 are merely examples. A transmitting / receiving coil having both transmitting and receiving functions may be used instead of the transmitting coil 45 and receiving coil 47. Furthermore, the transmitting coil 45, receiving coil 47, and transmitting / receiving coil may be combined.

[0018] A bed 13 is installed adjacent to the gantry 11. The bed 13 has a top plate 131 and a base 133. A subject P is placed on the top plate 131. The base 133 supports the top plate 131 so that it can slide along the X-axis, Y-axis, and Z-axis. A bed driving device 27 is housed in the base 133. The bed driving device 27 moves the top plate 131 under the control of a sequence control circuit 29. The bed driving device 27 may include any motor, such as a servo motor or a stepping motor.

[0019] The sequence control circuit 29 has, as hardware resources, a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit) and memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory). The sequence control circuit 29 synchronously controls the gradient magnetic field power supply 21, the transmission circuit 23, and the reception circuit 25 based on data acquisition conditions set by the processing circuit 51, and performs data acquisition on the subject P according to the data acquisition conditions to acquire k-space data related to the subject P. The sequence control circuit 29 is an example of a sequence control unit.

[0020] The sequence control circuit 29 according to this embodiment executes data acquisition for general MR images and data acquisition for magnetic resonance spectroscopy (hereinafter referred to as MRS (Magnetic Resonance Spectroscopy)), which is a type of chemical shift measurement. Data acquisition for MR images is a common technique, and therefore a detailed description thereof will be omitted. Chemical shift measurement is a technique for measuring chemical shifts, which are minute differences in the resonance frequencies of target protons, such as hydrogen nuclei, that occur depending on differences in chemical environment. MRS includes a single-voxel method for acquiring data for a single voxel and a multi-voxel method for acquiring data for multiple voxels. This embodiment is applicable to either method. The multi-voxel method is also called chemical shift imaging (CSI) or MRS imaging (MRSI). Note that voxels in the measurement target region are also called voxels of interest (VOI). In this embodiment, the region of interest (ROI) is a term that includes the voxels of interest.

[0021] The sequence control circuit 29 executes data acquisition for MRS on the subject P. By executing data acquisition for MRS, a free induction decay (FID) signal or a spin echo signal is generated from a voxel of interest in the subject P. The receiver circuit 25 receives the FID signal or spin echo signal via the receiver coil 47 and processes the received FID signal or spin echo signal to acquire k-space data for the voxel of interest. The acquired k-space data is digital data that represents the signal intensity value emitted from the voxel of interest as a function of time. The pulse sequence for MRS is repeated a number of times equal to the number of excitations (NEX), and k-space data corresponding to the number of excitations is acquired. Hereinafter, the k-space data acquired by MRS will be referred to as MRSk data. MRSk data is an example of an MRS signal.

[0022] In this embodiment, the MRS pulse sequence may be any pulse sequence used to acquire MRS signals, such as the LASER (localization by adiabatic selective refocusing) method, the ISIS method, the Semi-LASER method, or the PRESS method.

[0023] As shown in FIG. 1, the medical information processing device 50 is a computer having a processing circuit 51, a memory 53, a display 55, an input interface 57, and a communication interface 59.

[0024] The processing circuitry 51 has a processor such as a CPU as a hardware resource. The processing circuitry 51 functions as the core of the magnetic resonance data acquisition device 1. For example, the processing circuitry 51 realizes an acquisition function 511, a setting function 512, a generation function 513, a collection function 514, a display control function 515, and a determination function 516 by executing various programs.

[0025] The acquisition function 511 causes the processing circuit 51 to acquire the designated region of interest. The setting function 512 causes the processing circuitry 51 to set an acquisition method for acquiring magnetic resonance data multiple times. The generation function 513 causes the processing circuitry 51 to generate a pulse sequence for acquiring magnetic resonance data multiple times while changing at least one of the acquisition region and the setting conditions of the saturation pulse based on the region of interest. The acquisition function 514 causes the processing circuitry 51 to acquire a plurality of magnetic resonance data in accordance with a pulse sequence. The display control function 515 allows the processing circuitry 51 to control the display of a plurality of magnetic resonance data on, for example, a display 55 . The processing circuitry 51 determines, from the plurality of magnetic resonance data, the setting conditions for the region of interest or the saturation pulse such that the influence of a strong peak signal in the region to be acquired is equal to or less than a threshold value, using the determination function 516. Examples of the strong peak signal include fat signals and signals mixed in from outside the region to be acquired.

[0026] The memory 53 is a storage device such as an HDD (Hard Disk Drive), an SSD (Solid State Drive), or an integrated circuit storage device that stores various information. The memory 53 may also be a drive device that reads and writes various information from and to a portable storage medium such as a CD-ROM drive, a DVD drive, or a flash memory. For example, the memory 53 stores previously collected medical data, MRS signals, control programs, and the like.

[0027] The display 55 displays various information. As the display 55, for example, a CRT display, a liquid crystal display, an organic EL display, an LED display, a plasma display, or any other display known in the art can be appropriately used.

[0028] The input interface 57 includes input devices that accept various commands from the user. Examples of input devices that can be used include a keyboard, a mouse, various switches, a touch screen, and a touch pad. Note that the input devices are not limited to those equipped with physical operating parts such as a mouse and a keyboard. For example, an example of the input interface 57 also includes an electrical signal processing circuit that receives an electrical signal corresponding to an input operation from an external input device provided separately from the magnetic resonance data acquisition device 1 and outputs the received electrical signal to various circuits. The input interface 57 may also be a voice recognition device that converts a voice signal collected by a microphone into an instruction signal.

[0029] The communication interface 59 is an interface that connects the magnetic resonance data acquisition device 1 to a workstation, a PACS (Picture Archiving and Communication System), an HIS (Hospital Information System), a RIS (Radiology Information System), etc. via a LAN (Local Area Network), etc. The communication interface 59 transmits and receives various information to and from the connected workstation, PACS, HIS, and RIS.

[0030] Next, an example of the operation of the magnetic resonance data acquisition device 1 according to this embodiment will be described with reference to FIG. 2. The example of the operation shown in FIG. 2 assumes that the magnetic resonance data is data based on MRS signals, and assumes processing prior to the actual acquisition of MRS signals. Specifically, this is processing for determining the position of a region of interest or setting conditions for a saturation pulse, in which the influence of strong peak signals is reduced, when determining design conditions for the region of interest or saturation pulse. Note that, hereinafter, as an example of reducing the influence of strong peak signals, a case where the influence of fat is reduced is assumed. Also, here, it is assumed that an MR image of a subject P has been acquired in advance, and that a region of interest is specified on the MR image.

[0031] In step SA1, the processing circuitry 51 acquires the specified region of interest using the acquisition function 511. For example, a user may set a desired region of interest on an MR image acquired of the subject P. Alternatively, the processing circuitry 51 may set the region of interest in advance by referring to the case of the subject P or the past imaging history. In step SA2, the processing circuit sets the acquisition method using the setting function 512. The acquisition method may be set, for example, by a user. Specifically, the acquisition method is set to adopt a first method in which acquisition is performed multiple times by changing the acquisition region, a second method in which acquisition is performed multiple times by changing the saturation pulse around the region of interest, or both the first and second methods.

[0032] For example, when a region of the brain close to the scalp is set as the region of interest, it is considered that fat signals are likely to be contaminated with metabolite spectra, so it is possible to use the first method to shift the acquisition region toward the center of the head while searching for an acquisition position where MRS signals with the most fat suppression can be obtained. Alternatively, when the position of the region of interest acquired in step SA1 is respected, it is also possible to adopt the second method to determine what kind of saturation pulse should be set in order to acquire MRS signals in the region of interest. The method to be adopted may be set as a default, or may be set based on the position of the region of interest or case information. For example, if the subject is the head, the first method may be set to be adopted.

[0033] In step SA3, the processing circuitry 51 generates a pulse sequence based on the acquisition method using the generation function 513. The processing in step SA3 is a process for generating a sequence for acquiring MRS signals multiple times in order to determine the influence of fat as a pre-scan. Therefore, a pulse sequence is designed that shortens the acquisition time of MRS signals, for example by setting the number of integrations (NEX) to "1." For example, the repetition time (TR) of a pulse sequence for general main acquisition is about 2000 ms, but here the TR may be set to a shorter value, for example, about 500 to 800 ms.

[0034] Furthermore, the water suppression pulse does not need to be incorporated into the pulse sequence, or if incorporated into the pulse sequence, it may be simpler than the main acquisition. For example, instead of applying multiple pulses, such as WET (water suppression enhanced through T1 effects) or VAPOR (variable pulse power and optimized relaxation delays), it may be modified to apply one or two pulses. Alternatively, the bandwidth of the water suppression pulse may be widened. For example, if the spectral bandwidth to be suppressed by the water suppression pulse is normally 1 ppm, this may be changed to 2 ppm to widen the bandwidth. Furthermore, the readout time may be set to half or three-quarters of that in the case of main acquisition. In other words, any method may be adopted as long as it shortens the TR.

[0035] In step SA4, the processing circuitry 51 uses the acquisition function 514 to acquire magnetic resonance data corresponding to multiple acquisitions, here multiple MRS signals, in accordance with the pulse sequence generated in step SA3. In step SA5, the processing circuitry 51 displays spectra corresponding to the collected MRS signals using the display control function 515. The corresponding acquisition regions or acquisition conditions may be displayed alongside the spectra.

[0036] Next, a detailed example of the operation of the magnetic resonance data acquisition device 1 in the case of an acquisition method including the first technique will be described with reference to the flowchart of FIG. In step SB1, the processing circuit 51 acquires the designated region of interest using the acquisition function 511. In step SB2, the setting function 512 causes the processing circuitry 51 to set an acquisition method including the first technique.

[0037] In step SB3, the processing circuitry 51 determines the search direction of the region of interest using the setting function 512. The search direction may be determined by a user specifying the search direction or by automatic estimation. In the case of automatic estimation, the processing circuitry 51 may estimate the direction perpendicular to the contour of the region of interest using, for example, a trained model or pattern matching, and determine the direction as the search direction. Specifically, the region of interest may be input and the direction perpendicular to the contour of the region of interest may be estimated using a trained model trained to estimate the direction perpendicular to the region of interest, or the direction perpendicular to the contour of the region of interest may be estimated by pattern matching. In step SB4, the processing circuitry 51 sets a pulse sequence based on the first technique using the generation function 513. That is, a pulse sequence is set for acquiring data multiple times while moving the region of interest along the search direction.

[0038] In step SB5, the acquisition function 514 causes the processing circuitry 51 to acquire MRS signals for each of the multiple regions of interest in accordance with the pulse sequence. In step SB6, the display control function 515 causes the processing circuitry 51 to display a spectrum corresponding to each of the collected MRS signals.

[0039] In step SB7, the processing circuitry 51 determines, in response to a user instruction, a region of interest desired by the user from among the multiple acquisition regions as the main acquisition region of interest using the determination function 516. Specifically, for example, the processing circuitry 51 displays multiple regions of interest and corresponding MRS signals on the display 55 using the display control function 515. The user selects the desired region of interest. The processing circuitry 51 acquires the selection as a user instruction using the determination function 516 and determines the selected region of interest as the main acquisition region of interest. Alternatively, the processing circuitry 51 may use the determination function 516 to select, as the main acquisition region of interest, a region of interest corresponding to a spectrum with the least influence of fat. For example, the position of the region of interest corresponding to a spectrum in which the peak value of fat is equal to or less than a threshold value may be determined as the main acquisition region of interest. In step SB8, the acquisition function 514 allows the processing circuitry 51 to execute main acquisition on the main acquisition region of interest, thereby acquiring MRS signals with reduced fat. Note that the method of displaying a spectrum based on an MRS signal is not limited to displaying a spectrum based on each of a plurality of MRS signals. For example, the processing circuitry 51 may use the determination function 516 to select one of the plurality of acquisition regions from which fat is most suppressed and from which desired signals can be acquired as the main acquisition region of interest. In this case, the processing of step SB6 may be omitted, and the display control function 515 may cause the processing circuitry 51 to display the selected one main acquisition region of interest.

[0040] Next, an example of setting the collection region using the first method will be described with reference to FIG. FIG. 4 shows an example in which an acquisition region including multiple regions of interest is set on an MR image 30 of a subject P. Multiple MRS signals are acquired while the region of interest is moved every TR along a search direction 34. For example, when a region of interest 31 is specified in the vertex of the head, three regions of interest 31 to 33 are set as acquisition regions in the example of FIG. 4, and basically, MRS signals may be acquired by changing the region of interest every TR while changing the frequency shift of the slice selection pulse (in the z-axis direction). Note that the processing circuitry 51 may set multiple acquisition regions using the setting function 512 with the y-axis and x-axis directions as search directions.

[0041] Here, an example is shown in which multiple acquisition regions are set from region of interest 31 toward the inside of the head as acquisition regions along search direction 34, but multiple acquisition regions may be set toward the outside of the head, or multiple acquisition regions may be set in the up-down direction (front-back direction) based on the region of interest. For example, if the specified region of interest is region of interest 33, regions of interest 32 and 31 may be set as acquisition regions toward the outside of the head. Furthermore, the search direction 34 is not limited to a direction perpendicular to the set region of interest, but may be a diagonal direction or a rotational direction. For example, a region of interest may be set around the region of interest, and a collection region may be set around the region of interest. In other words, it is sufficient to set a region that can be searched for better candidate regions of interest around the specified region of interest.

[0042] Note that the shimming adjustment value differs for each position of the regions of interest 31 to 33, but for example, the shimming value may be adjusted for a region of interest that is considered to be less affected by fat among the multiple acquisition regions. In Fig. 4, the region of interest 33 is less affected by fat than the region of interest 31, so the shimming value may be adjusted for the region of interest 33. Alternatively, the shimming value may be adjusted for the entire acquisition region. That is, in FIG. 4, the shimming value may be adjusted for the sum of the regions of interest 31 to 33. Furthermore, as a method for adjusting shimming with higher precision, a shimming value may be calculated for each of a plurality of acquisition regions, and when acquiring MRS signals from the target regions of interest, adjustment may be made using the corresponding shimming value. That is, in FIG. 4, a shimming value may be calculated in advance for each of the regions of interest 31 to 33, and adjustment may be made by referring to the corresponding shimming value during acquisition.

[0043] Next, a detailed example of the operation of the magnetic resonance data acquisition device 1 in the case of an acquisition method including the second technique will be described with reference to the flowchart of FIG. In step SC1, the processing circuit 51 acquires the designated region of interest using the acquisition function 511. In step SC2, the setting function 512 causes the processing circuitry 51 to set an acquisition method including the second technique.

[0044] In step SC3, the processing circuitry 51 uses the setting function 512 to set a change pattern for the position, angle, and number of saturation pulses relative to the region of interest. For example, to change the position of the saturation pulse, a pattern can be set in which the saturation pulse position is set to the right of the region of interest in the first acquisition and to the left of the region of interest in the second acquisition. Similarly, to change the angle of the saturation pulse, a change can be set such as 30 degrees in the first acquisition and 45 degrees in the second acquisition. To change the number of saturation pulses, a change can be set such as two in the first acquisition and three in the second acquisition. Of course, changes in the position, angle, and number of saturation pulses may be combined. In step SC4, the processing circuitry 51 uses the generation function 513 to generate a pulse sequence based on the changed pattern.

[0045] In step SC5, the processing circuitry 51 acquires a plurality of MRS signals using the acquisition function 514 based on the pulse sequence, that is, while changing each saturation pulse condition according to the saturation pulse change pattern. In step SC6, the display control function 515 causes the processing circuitry 51 to display a spectrum based on the collected MRS signals.

[0046] In step SC7, the processing circuitry 51, via the determination function 516, determines, in response to a user instruction, the user's desired condition from among the conditions in the change pattern as the main acquisition saturation pulse setting. Specifically, for example, the display control function 515 causes the processing circuitry 51 to display each condition in the change pattern and the corresponding spectrum on the display 55. The user selects a desired saturation pulse change pattern. The determination function 516 causes the processing circuitry 51 to acquire the selection as a user instruction and determine the selected saturation pulse change pattern as the main acquisition saturation pulse setting. Alternatively, the determination function 516 may cause the processing circuitry 51 to select, as the main acquisition saturation pulse setting, the saturation pulse conditions that result in a spectrum with the least influence of fat. In other words, the main acquisition saturation pulse setting may be selected as the main acquisition saturation pulse setting, the saturation pulse conditions that correspond to a spectrum whose peak value of fat is below a threshold. The saturation pulse setting criterion is that the saturation pulse be set as close as possible to the intended region of interest without deviating from it. Furthermore, conditions may be set that minimize the contamination of fat signals into the region of interest and minimize the number of saturation pulses. In step SC8, the processing circuitry 51 applies a saturation pulse based on the main acquisition saturation pulse setting using the acquisition function 514, executes main acquisition using a pulse sequence related to main acquisition, and acquires MRS signals.

[0047] Next, an example of setting a change pattern of saturation pulses according to the second method will be described with reference to FIG. 6 shows an example in which a region of interest 31 is set on an MR image 30 of a subject P, and saturation pulses 61 to 63 are set around the region of interest 31. Here, the following change patterns are set: a condition for applying a saturation pulse, one saturation pulse 61, a condition for applying two saturation pulses 61 and 62, and a condition for applying three saturation pulses: 61, 62, and 63. Since a short acquisition time is also desirable for the actual acquisition, the spectra based on the MRS data acquired under each condition are referenced, and the condition with the fewest number of saturation pulses that achieves fat suppression, i.e., the influence of fat on the spectrum is below a threshold, can be determined as the actual acquisition saturation pulse setting. When the acquisition method includes both the first method and the second method, the processes shown in Fig. 3 and Fig. 5 may be performed in combination. For example, a combination may be performed in which a saturation pulse 61 is set in the first acquisition of the regions of interest 31-33 shown in Fig. 4, and saturation pulses 61-62 are set in the second acquisition of the regions of interest 31-33.

[0048] In the above example, it is assumed that a single voxel is set as the region of interest by the single voxel method, but the same processing can be applied even when collecting data by the multi-voxel method relating to a plurality of voxels.

[0049] In the multi-voxel method, since a region of interest exists within the FOV (Field of View), magnetic resonance data may be acquired multiple times while changing at least one of the acquisition region and the saturation pulse as described above, based on the region of interest within the FOV. Note that magnetic resonance data for fat determination as described above may also be acquired multiple times based on the entire FOV.

[0050] Furthermore, magnetic resonance data for the fat determination described above may be collected multiple times using an intermediate region between the FOV and the region of interest as a reference. For example, if a single voxel size of 1x1 is used as a reference, and the FOV has a voxel size of 12x12 and the region of interest has a voxel size of 4x4, an intermediate region of 8x8 voxel size may be used as a reference. In addition, when collecting data using the multi-voxel method, the above-mentioned determination process may be performed using any region within the FOV as a reference.

[0051] Next, examples of display by the display control function 515 will be described with reference to FIGS. FIG. 7 shows an example of a display of spectra of multiple MRS signals based on the acquisition method according to the first technique. The left side shows a spectrum 70 based on the MRS signals, and the right side shows the positions of the regions of interest set on the MR image 30 corresponding to the spectrum 70. Here, the positions of the regions of interest 31 to 33 are displayed in association with each other for three spectra. Note that the spectrum 70 and the MR image 30 with the regions of interest specified may be displayed in different windows. The user can select the position of the desired region of interest.

[0052] Furthermore, the maximum number of times MRS signals have been acquired and the number of times of acquisition indicating the current number of acquisitions may be displayed in association with the spectrum 70 or the MR image 30 including the region of interest. Furthermore, the search direction and the amount of movement from a reference region of interest may be displayed in association with the spectrum 70 or the MR image 30 including the region of interest. Alternatively, the processing circuitry 51 may use the display control function 515 to display one spectrum 70 and the corresponding MR image 30 on the screen, and dynamically switch between spectra for each region of interest or each acquisition condition by scrolling with a mouse, etc. This allows the user to dynamically confirm changes in the spectrum in response to changes in the position of the region of interest or the acquisition conditions.

[0053] The displayed MR image 30 may be a cross-sectional image in which a region of interest is set. In this embodiment, since the influence of fat on the spectrum is determined, for example, if the region of interest is specified at the vertex, a sagittal MR image may be displayed, and if it is part of the left or right hemisphere of the head, a coronal or horizontal MR image may be displayed.

[0054] As shown in FIG. 7, the spectrum 70 obtained differs for each of the multiple regions of interest. For example, in the upper diagram of FIG. 7, the adipose tissue surrounding the region of interest is excited, and the influence of fat is significant, making it impossible to detect the metabolite spectrum. On the other hand, in the lower diagram of FIG. 7, the influence of fat is small, and the metabolite spectrum can be visually grasped. The user can determine the region of interest corresponding to the spectrum that is not contaminated with fat as the region of interest for actual collection.

[0055] Next, FIG. 8 shows an example of displaying a plurality of MR data sets based on the acquisition method according to the second technique. The left side shows a spectrum 70 based on MRS data, and the right side shows the setting conditions for the saturation pulse corresponding to that spectrum, which are displayed in association with each other on the MR image as saturation pulses 61 to 63. Here, the saturation pulse conditions are displayed in association with each of the three spectra 70. As in the case of FIG. 7, the user can refer to the spectrum 70 to select the optimum main acquisition saturation pulse setting for the saturation pulse.

[0056] 7 and 8 and the region of interest or saturation pulse conditions may be switched for each acquisition and displayed in real time. For example, after the acquisition of the MRS signals shown in the upper diagram of FIG. 7 is completed, the processing circuitry 51, using the display control function 515, displays the image-processed spectrum 70 shown in the upper diagram of FIG. 7 on the screen. When the acquisition of the next MRS signal is completed, the spectrum 70 is switched to the spectrum 70 shown in the middle diagram of FIG. 7. In addition, when a spectrum is displayed in real time, if the user determines that the desired spectrum has been obtained, the MR data acquisition may be terminated midway. For example, when the desired spectrum is displayed, the currently displayed region of interest or saturation pulse conditions may be determined as the main acquisition region of interest or main acquisition saturation pulse setting by pressing or clicking a predetermined button. Furthermore, when the magnetic resonance data acquisition device automatically determines the main acquisition region of interest or main acquisition saturation pulse setting, for example, the region of interest or saturation pulse corresponding to the spectrum in which the fat peak is less than one-tenth of the peak value of the metabolite NAA may be selected. The display control function 515 causes the processing circuitry 51 to display the selected spectrum, allowing the user to easily visually recognize the shape of the spectrum and confirm the spectrum that served as the basis for the determination.

[0057] In the above example, it is assumed that the magnetic resonance data is data based on MRS signals, but this is not limiting. For example, in the CEST (Chemical Exchange Saturation Transfer) method, which images trace molecules by utilizing the proton exchange phenomenon between protons in molecules and bulk water in a living body, the determination process of the magnetic resonance data acquisition device according to this embodiment can be used to suppress fat signals.

[0058] According to the present embodiment described above, the generator generates a pulse sequence for acquiring magnetic resonance data multiple times while changing at least one of the acquisition region and the setting conditions of the saturation pulse based on the region of interest. The acquisition unit acquires multiple pieces of magnetic resonance data in accordance with the pulse sequence. This allows the position of the region of interest and the setting conditions of the saturation pulse, which can be used in the actual acquisition and reduce the contamination of the magnetic resonance data with fat signals, to be determined from a spectrum based on the multiple pieces of magnetic resonance data. Whether determined by a user or automatically by an apparatus, the position of the region of interest or the setting conditions of the saturation pulse can be determined while comparing multiple regions of interest with reference to the spectrum, thereby reducing dependency on the operator and accurately reducing the influence of fat signals on the spectrum.

[0059] The term "processor" used in the above description refers to a circuit such as a central processing unit (CPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), or a programmable logic device (e.g., a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), or a field programmable gate array (FPGA)). If the processor is a CPU, for example, the processor realizes its function by reading and executing a program stored in a memory circuit. On the other hand, if the processor is an ASIC, for example, instead of storing the program in a memory circuit, the function is directly incorporated into the processor circuit as a logic circuit. Note that each processor in this embodiment is not limited to being configured as a single circuit per processor, but may be configured as a single processor by combining multiple independent circuits to realize its function. Furthermore, multiple components in the diagram may be integrated into a single processor to realize its function.

[0060] In addition, each function according to the embodiment can be realized by installing a program that executes the above-described processes in a computer such as a workstation and expanding the program in memory. In this case, the program that causes the computer to execute the above-described method can be stored and distributed on a storage medium such as a magnetic disk (such as a hard disk), an optical disk (such as a CD-ROM or DVD), or a semiconductor memory.

[0061] Although several embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations of embodiments can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0062] 1. Magnetic resonance data acquisition device 11 Mounting stand 13 berths 21 Gradient magnetic field power supply 23 Transmitting circuit 25 Receiving circuit 27 Bed drive unit 29 Sequence control circuit 30 MR images 31-33 Areas of Interest 34 Search direction 41 Static magnetic field magnet 43 Gradient magnetic field coil 45 Transmitting coil 47 receiving coil 50 Medical information processing device 51 Processing circuit 53 Memory 55 Display 57 Input Interface 59 Communication Interface 61-63 Saturation pulse 70 Spectra 131 Top plate 133 Foundation 511 Acquisition Function 512 Setting Function 513 Generation function 514 Collection Function 515 Display Control Function 516 Decision Function

Claims

1. an acquisition unit that acquires a designated region of interest; a generator for generating a pulse sequence for acquiring magnetic resonance data a plurality of times while changing at least one of an acquisition region and a setting condition of a saturation pulse based on the region of interest; an acquisition unit that acquires a plurality of magnetic resonance data in accordance with the pulse sequence; A magnetic resonance data acquisition device comprising:

2. 2. The magnetic resonance data acquisition apparatus according to claim 1, further comprising a determination unit that determines, from the plurality of magnetic resonance data, setting conditions for a region of interest or a saturation pulse such that the influence of fat in the region to be acquired is equal to or less than a threshold.

3. a display control unit that controls to display at least one of the acquisition region and the setting condition of the saturation pulse changed by the generation unit, and corresponding magnetic resonance data; A determination unit that determines setting conditions for a region of interest or a saturation pulse, based on setting conditions for one acquisition region or one saturation pulse selected by a user, such that the influence of a strong peak signal in the acquisition target region is equal to or less than a threshold; 10. The magnetic resonance data acquisition device of claim 1, further comprising:

4. the generator generates a pulse sequence for acquiring magnetic resonance data a plurality of times while shifting the position of the region of interest along a specified search direction; The magnetic resonance data acquisition apparatus according to claim 1 , wherein the plurality of magnetic resonance data are data corresponding to each position of the changed region of interest.

5. the generating unit generates a pulse sequence for acquiring magnetic resonance data a plurality of times while changing at least one condition of a position, an angle, and the number of the saturation pulses; 2. The magnetic resonance data acquisition apparatus according to claim 1, wherein the plurality of magnetic resonance data are data corresponding to each of the conditions of the changed saturation pulse.

6. The magnetic resonance data acquisition apparatus according to claim 1 , wherein the generator generates a pulse sequence having a repetition time shorter than that of a main acquisition when the magnetic resonance data is acquired multiple times.

7. Get the specified region of interest, generating a pulse sequence for acquiring magnetic resonance data a plurality of times while changing at least one of an acquisition region and a setting condition of a saturation pulse based on the region of interest; A magnetic resonance data acquisition method for acquiring a plurality of magnetic resonance data in accordance with the pulse sequence.

8. On the computer, an acquisition function for acquiring a specified region of interest; a generation function for generating a pulse sequence for acquiring magnetic resonance data a plurality of times while changing at least one of an acquisition region and a setting condition of a saturation pulse based on the region of interest; and an acquisition function for acquiring a plurality of pieces of magnetic resonance data in accordance with the pulse sequence.

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