Magnetic resonance data collection device, magnetic resonance data collection method, and magnetic resonance data collection program storage medium

Abstract

The present invention addresses the problem of reducing dependency on an operator and reducing the influence of a fat signal on a frequency spectrum with high precision. A magnetic resonance data collection device according to an embodiment includes an acquisition unit, a generation unit, and a collection unit. The acquisition unit acquires a specified region of interest. The generation unit generates a pulse sequence for collecting magnetic resonance data multiple times while changing at least one of a collection region and a saturation pulse setting condition based on the region of interest. The collection unit collects a plurality of magnetic resonance data in accordance with the pulse sequence.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to a magnetic resonance data collection apparatus, a magnetic resonance data collection method, and a magnetic resonance data collection program storage medium BACKGROUND

[0002] In the collection of a magnetic resonance spectroscopy signal, if a fat signal is mixed in, analysis becomes difficult. Therefore, for example, a method of suppressing a signal band of fat by a saturation pulse or the like, a method of suppressing a region in which fat can exist by a saturation pulse or the like, or a method of adjusting a VOI so as to exclude a region in which fat can exist from a region of interest (VOI: Volume of Interest) is considered.

[0003] However, in the method of suppressing a signal band of fat by a saturation pulse, the influence of the suppression is not limited to a fat signal, but also causes an influence on a spectrum of a signal of a desired metabolite. In addition, in the method of suppressing a region in which fat can exist, or the method of adjusting a VOI so as to exclude from a VOI, fine adjustment needs to be made by a human, and there is a problem that a deviation in precision occurs depending on an empirical value, ability.

[0004] PRIOR ART DOCUMENTS

[0005] Patent Document 1: Japanese Patent Application Laid-Open (JP A) No. 2001-187038 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] One of the problems to be solved by the embodiments disclosed in the present specification and the drawings is to be able to reduce the influence of a fat signal on a spectrum with high precision and reduce dependence on an operator. However, the problems to be solved by the embodiments disclosed in the present specification and the drawings are not limited to the above problem. The problems corresponding to each effect of each configuration shown in the embodiments described later can also be positioned as other problems.

[0008] The magnetic resonance data collection apparatus of the present embodiment includes an acquisition unit, a generation unit, and a collection unit. The acquisition unit acquires a specified region of interest. The generation unit generates a pulse sequence for collecting magnetic resonance data a plurality of times while changing at least one of a collection region and a set condition of a saturation pulse with the region of interest as a reference. The collection unit collects a plurality of magnetic resonance data in accordance with the pulse sequence.

[0009] EFFECTS OF THE INVENTION

[0010] The present application is to be able to reduce the influence of a fat signal on a spectrum with high precision and reduce dependence on an operator.​ Attached Figure Description

[0011] Figure 1 This is a block diagram illustrating the magnetic resonance data collection apparatus of this embodiment.

[0012] Figure 2 This is a flowchart illustrating an example of the operation of a magnetic resonance data acquisition device.

[0013] Figure 3 This is a flowchart illustrating a detailed operational example of a magnetic resonance data acquisition device, including the first method of acquisition.

[0014] Figure 4 This is a diagram illustrating an example of setting the region of interest based on the first method.

[0015] Figure 5 This is a flowchart illustrating a detailed operational example of a magnetic resonance data acquisition device in the case of a acquisition method including the second method.

[0016] Figure 6 This is a diagram illustrating an example of setting the saturation pulse change mode for the second method.

[0017] Figure 7 This is a diagram showing an example of the spectrum of multiple MRS signals collected using the first method.

[0018] Figure 8 This is a diagram showing an example of the spectrum of multiple MRS signals collected using the second method.

[0019] Explanation of reference numerals in the attached figures

[0020] 1. Magnetic Resonance Data Acquisition Device

[0021] 11 racks

[0022] 13. Examination Bed

[0023] 21 Inclined Magnetic Field Power Supply

[0024] 23 Transmitting Circuit

[0025] 25. Receiving Circuit

[0026] 27. Examination bed drive unit

[0027] 29. Sequence Control Circuit

[0028] 30MR images

[0029] Areas of concern 31-33

[0030] 34 Search Directions

[0031] 41. Static magnetic field magnet

[0032] 43 Gradient coil

[0033] 45 Transmit coil

[0034] 47 Receive coil

[0035] 50 Medical information processing apparatus

[0036] 51 Processing circuitry

[0037] 53 Memory

[0038] 55 Display

[0039] 57 Input interface

[0040] 59 Communication interface

[0041] 61-63 Saturation pulses

[0042] 70 Frequency spectrum

[0043] 131 Ceiling

[0044] 133 Base

[0045] 511 Acquisition function

[0046] 512 Setting function

[0047] 513 Generation function

[0048] 514 Collection function

[0049] 515 Display control function

[0050] 516 Decision function DETAILED DESCRIPTION

[0051] Hereinafter, a magnetic resonance data collection apparatus, a magnetic resonance data collection method, and a magnetic resonance data collection program according to the present embodiment will be described with reference to the accompanying drawings. In the following embodiments, portions denoted by the same reference numerals perform the same actions, and repeated descriptions will be appropriately omitted. Hereinafter, an embodiment will be described with reference to the drawings.

[0052] Figure 1 is a block diagram showing a configuration example of the magnetic resonance data collection apparatus according to the present embodiment. As shown in Figure 1 , the magnetic resonance data collection apparatus 1 is, for example, a magnetic resonance imaging apparatus. It has a stand 11, a couch 13, a gradient magnetic field power supply 21, a transmit circuit 23, a receive circuit 25, a couch drive apparatus 27, a sequence control circuit 29, and a medical information processing apparatus (host computer) 50.

[0053] The stand 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 stand 11. A hole having a hollow shape is formed in the housing of the stand 11. A transmitting coil 45 and a receiving coil 47 are disposed in the hole of the stand 11.

[0054] The static magnetic field magnet 41 has a hollow substantially cylindrical shape, and generates a static magnetic field inside the substantially cylindrical shape. As the static magnetic field magnet 41, for example, a permanent magnet, a superconducting magnet, or a resistive magnet is used. Here, a central axis of the static magnetic field magnet 41 is defined as a Z axis, an axis orthogonal to the Z axis is defined as a Y axis, and an axis orthogonal to the Z axis horizontally is defined as an X axis. The X axis, the Y axis, and the Z axis constitute an orthogonal three-dimensional coordinate system.

[0055] The gradient magnetic field coil 43 is installed inside the static magnetic field magnet 41, and is a coil unit formed in a hollow substantially cylindrical shape. The gradient magnetic field coil 43 generates a gradient magnetic field by receiving supply of a current from the gradient magnetic field power supply 21. More specifically, the gradient magnetic field coil 43 has three coils corresponding to the X axis, the Y axis, and the Z axis orthogonal to each other. The three coils generate a gradient magnetic field in which a magnetic field strength varies along each of the X axis, the Y axis, and the Z axis. The gradient magnetic fields along each of the X axis, the Y axis, and the Z axis are synthesized to form a frequency encoding gradient magnetic field Gr, a phase encoding gradient magnetic field Gp, and a slice selection gradient magnetic field Gs orthogonal to each other in a desired direction. The frequency encoding gradient magnetic field Gr is used to vary a 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 vary a phase of the MR signal according to a spatial position. The slice selection gradient magnetic field Gs is used to arbitrarily decide a photographing cross section (slice). In addition, in the following description, it is assumed that a gradient direction of the frequency encoding gradient magnetic field Gr is the X axis, a gradient direction of the phase encoding gradient magnetic field Gp is the Y axis, and a gradient direction of the slice selection gradient magnetic field Gs is the Z axis.

[0056] The gradient magnetic field power supply 21 supplies a current to the gradient magnetic field coil 43 according to a sequence control signal from the sequence control circuit 29. The gradient magnetic field power supply 21 generates the gradient magnetic field along each of the X axis, the Y axis, and the Z axis by supplying the current to the gradient magnetic field coil 43. The gradient magnetic field overlaps the static magnetic field formed by the static magnetic field magnet 41 and is applied to the subject P.

[0057] The transmitting coil 45 is disposed, for example, inside the gradient magnetic field coil 43, and generates a high frequency pulse (hereinafter, referred to as an RF pulse) by receiving supply of a current from the transmitting circuit 23.

[0058] The transmission circuit 23 supplies a current to the transmission coil 45 in order to apply an RF pulse for exciting subject protons existing in the subject P to the subject P via the transmission coil 45. The RF pulse vibrates at a resonance frequency inherent to the subject protons, exciting the subject protons. An MR signal is generated from the excited subject protons, which is detected by the reception coil 47. The transmission coil 45 is, for example, a whole-body coil (WB coil). The whole-body coil can also be used as a transceiver coil.

[0059] The reception coil 47 receives an MR signal emitted from subject protons existing in the subject P under the action of an RF pulse. The reception coil 47 has a plurality of reception coil elements capable of receiving an MR signal. The received MR signal is supplied to the reception circuit 25 via wire or wireless. Although not illustrated in FIG. 1, the reception coil 47 has a plurality of reception channels installed in parallel. The reception channel has a reception coil element that receives an MR signal and an amplifier or the like that amplifies the MR signal. The MR signal is output per reception channel. The total number of reception channels can be the same as the total number of reception coil elements, can be more than the total number of reception coil elements, or can be less than the total number of reception coil elements. Figure 1

[0060] The reception circuit 25 receives an MR signal generated from the excited subject protons via the reception coil 47. The reception circuit 25 performs signal processing on the received MR signal to generate a digital MR signal. The digital MR signal can be expressed in k-space defined by spatial frequency. Therefore, hereinafter, the digital MR signal will be referred to as k-space data. The k-space data is an example of an MR collection signal. The k-space data is supplied to the medical information processing apparatus 50 via wire or wireless.

[0061] In addition, the above-described transmission coil 45 and reception coil 47 are merely an example. Instead of the transmission coil 45 and the reception coil 47, a transceiver coil having a transmission function and a reception function can be used. In addition, the transmission coil 45, the reception coil 47, and the transceiver coil can be combined.

[0062] The examination bed 13 is provided adjacent to the stand 11. The examination bed 13 has a top plate 131 and a base 133. The subject P is placed on the top plate 131. The base 133 supports the top plate 131 so as to be slidable along the X-axis, the Y-axis, and the Z-axis, respectively. The examination bed driving apparatus 27 is housed in the base 133. The examination bed driving apparatus 27 moves the top plate 131 in accordance with a control from the sequence control circuit 29. The examination bed driving apparatus 27 can include, for example, any motor such as a servo motor or a step motor.

[0063] ​The sequence control circuit 29 has a processor of a CPU (Central Processing Unit) or an MPU (Micro Processing Unit) and a memory such as a ROM (Read Only Memory) and a RAM (Random Access Memory) as hardware resources. The sequence control circuit 29 controls the gradient magnetic field power supply 21, the transmission circuit 23, and the reception circuit 25 in synchronization based on a data collection condition set by the processing circuit 51, implements data collection corresponding to the data collection condition on the subject P, and collects k-space data related to the subject P. The sequence control circuit 29 is an example of a sequence control unit.

[0064] The sequence control circuit 29 of the present embodiment performs data collection for a general MR image and data collection for magnetic resonance spectroscopy (hereinafter, referred to as MRS (Magnetic Resonance Spectroscopy)) which is one of chemical shift measurements. The data collection for the MR image is a general method, and thus detailed description is omitted. The chemical shift measurement is a technique of measuring a chemical shift which is a slight difference in resonance frequency of a target proton such as a hydrogen nucleus due to a difference in chemical environment. The MRS has a single voxel method of performing data collection for a single voxel or a multi-voxel method of performing data collection for a plurality of voxels, and the present embodiment can be applied to any method. The multi-voxel method is also referred to as chemical shift imaging (CSI: Chemical Shift Imaging) or MRS imaging (MRSI: MRS Imaging), or the like. In addition, a voxel of a measurement target region is also referred to as a voxel of interest (VOI: Voxel of Interest). In the present embodiment, a region including the voxel of interest is referred to as a region of interest (ROI).

[0065] The sequence control circuit 29 performs data collection for MRS on the subject P. By performing the data collection for MRS, a free induction decay (FID) signal or a spin echo signal is generated from the voxel of interest of the subject P. The reception circuit 25 receives the FID signal or the spin echo signal via the reception coil 47, performs signal processing on the received FID signal or spin echo signal, and collects k-space data related to the voxel of interest. The collected k-space data is digital data representing a signal intensity value emitted from the voxel of interest as a function of time. The number of pulse sequence repetitions (NEX: number of excitation) for MRS is repeated, and the k-space data of the number of accumulations is collected. Hereinafter, the k-space data collected by MRS is referred to as MRS k data. The MRS k data is an example of MRS signal.

[0066] Further, as the MRS pulse sequence, in the present embodiment, it is only necessary to be a pulse sequence for collecting MRS signals such as LASER (localization by adiabatic selective refocusing) method, ISIS method, Semi-LASER method, PRESS method.

[0067] As shown in FIG. 1, the medical information processing apparatus 50 is a computer having a processing circuit 51, a memory 53, a display 55, an input interface 57, and a communication interface 59. Figure 1

[0068] The processing circuit 51 has a processor such as a CPU as a hardware resource. The processing circuit 51 functions as a hub of the magnetic resonance data collection apparatus 1. For example, the processing circuit 51 realizes a obtaining function 511, a setting function 512, a generating function 513, a collecting function 514, a display control function 515, and a deciding function 516 by execution of various programs.

[0069] By the obtaining function 511, the processing circuit 51 obtains a specified region of interest.

[0070] By the setting function 512, the processing circuit 51 sets a collecting method for collecting a plurality of magnetic resonance data.

[0071] By the generating function 513, the processing circuit 51 generates a pulse sequence for collecting magnetic resonance data a plurality of times while changing at least one of a collecting region and a setting condition of a saturation pulse with the region of interest as a reference.

[0072] By the collecting function 514, the processing circuit 51 collects a plurality of magnetic resonance data in accordance with the pulse sequence.

[0073] By the display control function 515, the processing circuit 51 controls so as to display the plurality of magnetic resonance data on, for example, the display 55.

[0074] By the deciding function 516, the processing circuit 51 decides a region of interest or a setting condition of a saturation pulse in which an influence of a strong peak signal in a region of collection object is below a threshold value, from a plurality of magnetic resonance data. As the strong peak signal, for example, a fat signal, a signal mixed from outside the region of collection object, and the like can be cited.

[0075] ​The memory 53 is a storage device such as an HDD (Hard Disk Drive), an SSD (Solid State Drive), an integrated circuit storage device, or the like that stores various information. In addition, the memory 53 can also be a drive device or the like that reads and writes various information with a CD-ROM drive, a DVD drive, a flash memory, or the like. For example, the memory 53 stores medical data collected in the past, MRS signals, control programs, and the like.

[0076] 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 technical field can be appropriately used.

[0077] The input interface 57 includes an input device that receives various instructions from a user. As the input device, a keyboard, a mouse, various switches, a touch screen, a touch pad, or the like can be used. Furthermore, the input device is not limited to a device that has a physical operation member such as a mouse or a keyboard. For example, a processing circuit that accepts an electric signal corresponding to an input operation from an input device provided externally from the magnetic resonance data collection apparatus 1 and outputs the accepted electric signal to various circuits is also included in the example of the input interface 57. In addition, the input interface 57 can also be a voice recognition device that converts a voice signal collected by a microphone into an instruction signal.

[0078] The communication interface 59 is an interface that connects the magnetic resonance data collection apparatus 1 with a workstation, a PACS (Picture Archiving and Communication System), a HIS (Hospital Information System), a RIS (Radiology Information System), or the like via a LAN (Local Area Network) or the like. The communication interface 59 transmits and receives various information with the connected workstations, PACS, HIS, and RIS.

[0079] Next, the operation example of the magnetic resonance data collection apparatus 1 according to the present embodiment will be described with reference to FIG. 6. Figure 2 The operation example shown in FIG. 6 assumes that data based on an MRS signal is used as magnetic resonance data and assumes a process in a pre-stage of formally collecting an MRS signal. Specifically, it is a process for determining a position of a region of interest or a setting condition of a saturation pulse that reduces an influence of a strong peak signal when a design condition of the region of interest or the saturation pulse is determined. Furthermore, hereinafter, as an example of reducing an influence of a strong peak signal, a case of reducing an influence of fat is assumed. In addition, here, it is assumed that an MR image for the subject P is obtained in advance, and a region of interest is specified on the MR image. Figure 2 The operation example shown in FIG. 6 assumes that data based on an MRS signal is used as magnetic resonance data and assumes a process in a pre-stage of formally collecting an MRS signal. Specifically, it is a process for determining a position of a region of interest or a setting condition of a saturation pulse that reduces an influence of a strong peak signal when a design condition of the region of interest or the saturation pulse is determined. Furthermore, hereinafter, as an example of reducing an influence of a strong peak signal, a case of reducing an influence of fat is assumed. In addition, here, it is assumed that an MR image for the subject P is obtained in advance, and a region of interest is specified on the MR image.

[0080] In step SA1, the processing circuit 51 acquires the designated region of interest by the acquisition function 511. For example, the user can set a desired region of interest on an MR image taken with respect to the subject P. Alternatively, the processing circuit 51 can refer to a case of the subject P, a past history of imaging, and set the region of interest in advance.

[0081] In step SA2, the processing circuit sets the collection method by the setting function 512. The collection method can be set by user designation, for example. Specifically, it is set whether to use the first method of collecting multiple times by changing the collection region, the second method of collecting multiple times by changing the saturation pulse with respect to the periphery of the region of interest, or both the first and second methods.

[0082] For example, in a case where a portion close to the scalp in the brain is set as the region of interest, it is considered that a fat signal is easily mixed into the spectrum of metabolites, and thus it is considered to use the first method, search for a collection position where the MRS signal is obtained with the fat being most suppressed while shifting the collection region to the center side of the head, and collect. Alternatively, in a case where the position of the region of interest acquired in step SA1 is respected, it is also possible to determine what kind of saturation pulse is good to set in order to collect the MRS signal in the region of interest by using the second method.

[0083] Further, the method to be used can be set based on the position of the region of interest or information of the case. For example, if it is the head, it can be set to use the first method.

[0084] In step SA3, the processing circuit 51 generates a pulse sequence based on the collection method by the generation function 513. The processing of step SA3 is a generation process of a sequence for collecting the MRS signal multiple times in order to determine the influence of fat as a pre-scan. Therefore, a pulse sequence in which the number of accumulations (NEX) is set to "1" or the like, and the collection time of the MRS signal is shortened, is designed. For example, the repetition time (TR) of the pulse sequence involved in general formal collection is about 2000 ms, but here, for example, the TR can be set to be shorter, about 500 to 800 ms.

[0085] Further, it is also possible not to incorporate the water suppression pulse group into the pulse sequence, and in the case of incorporation into the pulse sequence, it is also possible to simplify compared to the formal collection. For example, it is also possible to change to not apply multiple pulses such as WET (water suppression enhanced through Tl effects), VAPOR (variable pulse power and optimized relaxation delays), but to apply one or two pulses.

[0086] In addition, it is also possible to widen the frequency band of the water suppression pulse. For example, normally, in the case where the frequency band of the spectrum to be suppressed by the water suppression pulse is 1 ppm, it is also possible to change to 2 ppm to widen the frequency band.

[0087] Further, compared to the formal collection, it is also possible to set the readout time to 1 / 2, 3 / 4 of the time, and the like. That is, as long as the TR becomes short, any method can be adopted.

[0088] In step SA4, by the collection function 514, the processing circuit 51 collects magnetic resonance data corresponding to the multiple collections, here, the multiple MRS signals, in accordance with the pulse sequence generated in step SA3.

[0089] In step SA5, by the display control function 515, the processing circuit 51 displays the spectrum corresponding to the collected multiple MRS signals respectively. It is also possible to arrange and display the corresponding collection region or collection condition together with the spectrum.

[0090] Next, the flowchart explanation is a detailed action example of the magnetic resonance data collection apparatus 1 in the case of the collection method including the first method. Figure 3

[0091] In step SB1, by the acquisition function 511, the processing circuit 51 acquires the specified region of interest.

[0092] In step SB2, by the setting function 512, the processing circuit 51 sets the collection method including the first method.

[0093] ​In step SB3, the processing circuit 51 decides the search direction of the region of interest by the setting function 512. The decision of the search direction can be made by the user designating the search direction, or can be automatically inferred. In the case of making an automatic inference, for example, the processing circuit 51 uses a learned model or pattern matching (Pattern matching) or the like, infers a direction perpendicular to the contour of the region of interest, and decides the direction as the search direction. Specifically, the direction perpendicular to the contour of the region of interest can be inferred using a learned model learned in such a manner that the region of interest is input and the direction perpendicular to the region of interest is inferred, or can be inferred by pattern matching.

[0094] In step SB4, the processing circuit 51 sets the pulse sequence based on the first method by the generation function 513. That is, the pulse sequence for collecting a plurality of times while moving the region of interest along the search direction is set.

[0095] In step SB5, the processing circuit 51 collects the MRS signals of the plurality of regions of interest respectively in accordance with the pulse sequence by the collection function 514.

[0096] In step SB6, the processing circuit 51 displays the spectra respectively corresponding to the plurality of collected MRS signals by the display control function 515.

[0097] In step SB7, the processing circuit 51 decides the region of interest desired by the user among the plurality of collected regions as the formal collection region of interest in accordance with the user's instruction by the decision function 516. Specifically, for example, the processing circuit 51 displays the plurality of regions of interest and the corresponding MRS signals on the display 55 by the display control function 515. The user selects the desired region of interest. The processing circuit 51 can decide the selected region of interest as the formal collection region of interest by the decision function 516 by taking the selection as the user's instruction. Alternatively, the processing circuit 51 can select the region of interest corresponding to the spectrum least affected by fat as the formal collection region of interest by the decision function 516. For example, the position of the region of interest corresponding to the spectrum whose peak value is below a threshold value can be decided as the formal collection region of interest.

[0098] In step SB8, the processing circuit 51 can perform formal collection with respect to the formal collection region of interest, and collect the MRS signal in which the influence of fat is reduced, by the collection function 514.

[0099] Further, as the display method of the spectrum based on the MRS signal, it is not limited to display the spectrum based on the plurality of MRS signals respectively. For example, by the decision function 516, the processing circuit 51 selects the region of interest in which the fat is most suppressed and the desired signal can be collected as one formal collection region of interest from among the plurality of collection regions of interest. In this case, the processing of the step SB6 can also be omitted, and the processing circuit 51 displays the selected one formal collection region of interest by the display control function 515.

[0100] Next, with reference to Figure 4 An example of setting the collection region based on the first method will be described.

[0101] Figure 4 In the example of setting the collection region of interest containing a plurality of regions of interest on the MR image 30 of the subject P. Along the search direction 34, a plurality of MRS signals are collected while moving the region of interest by every 1 TR. For example, in the case where the region of interest 31 is specified in the top of the head, the MRS signal can be collected by changing the frequency shift of the slice selection pulse (z-axis direction) while changing the region of interest by every 1 TR in the x-axis direction and the y-axis direction. Figure 4 In the example of FIG. 6, three regions of interest 31 to 33 are set as the collection region, and basically the MRS signal can be collected by changing the region of interest while changing the frequency shift of the slice selection pulse (z-axis direction) by every 1 TR. Further, by the setting function 512, the processing circuit 51 can set a plurality of collection regions of interest with the y-axis direction and the x-axis direction as the search direction.

[0102] Here, as the collection region along the search direction 34, an example of setting a plurality of regions of interest from the region of interest 31 toward the inside of the head is shown, but a plurality of regions of interest can also be set toward the outside of the head, and a plurality of regions of interest can also be set in the up-down direction (front-back direction) with the region of interest as a reference. For example, in the case where the specified region of interest is the region of interest 33, the region of interest 32 and the region of interest 31 can be set as the collection region toward the outside of the head.

[0103] In addition, the search direction 34 is not limited to the direction perpendicular to the set region of interest, and can be a tilted direction or a rotational direction. For example, the region of interest can be set in a manner of surrounding the periphery with the region of interest as the center, and the collection region can be set. That is, with the specified region of interest as a reference, the region of interest can be set in which there is no better candidate for the region of interest around the region of interest, or the region of interest can be set in which the search can be performed.

[0104] Further, the adjustment value of the shim is different for each position of the regions of interest 31 to 33, but for example, the region of interest in which the influence of the fat is considered to be small among the plurality of collection regions of interest can be targeted to adjust the shim value. In Figure 4 In the example of FIG. 6, the region of interest 33 has less influence of the fat than the region of interest 31, and thus the shim value can be adjusted with the region of interest 33 as the target.

[0105] Alternatively, the entire collection area can be treated as a single object to adjust the shimming value. That is, in Figure 4 In this case, the sum of the regions of interest (31-33) can be used as the object to adjust the shimming value. Furthermore, as a method for adjusting the shimming with higher precision, the shimming value can also be calculated for each of the multiple collection regions, and adjusted using the corresponding shimming value when collecting MRS signals from the region of interest of the object. That is, in Figure 4 In the process, the shim values ​​are pre-calculated in each region of interest 31 to 33, and then adjusted according to the corresponding shim values ​​during data collection.

[0106] Next, refer to Figure 5 The flowchart illustrates a detailed operational example of the magnetic resonance data acquisition device 1, including the second method of data acquisition.

[0107] In step SC1, the processing circuit 51 obtains the specified region of interest by acquiring function 511.

[0108] In step SC2, the processing circuit 51 sets a collection method including the second method by setting function 512.

[0109] In step SC3, the processing circuit 51 sets a change mode related to the position, angle, and number of saturation pulses relative to the region of interest through setting function 512. For example, if the position of the saturation pulse is changed, it can be set to the right side of the region of interest in the first collection and the left side in the second collection. Similarly, if the angle of the saturation pulse is changed, it can be set to 30 degrees in the first collection and 45 degrees in the second collection. If the number of saturation pulses is changed, it can be changed to 2 in the first collection and 3 in the second collection. Of course, changes to the position, angle, and number of saturation pulses can also be combined.

[0110] In step SC4, the processing circuit 51 generates a pulse sequence based on the changing pattern through the generation function 513.

[0111] In step SC5, through the collection function 514, the processing circuit 51 collects multiple MRS signals based on the pulse sequence, that is, according to the changing pattern of the saturation pulse, while changing the conditions of the saturation pulse.

[0112] In step SC6, the processing circuit 51 displays the spectrum based on the collected multiple MRS signals through the display control function 515.

[0113] In step SC7, through the decision function 516, the processing circuit 51 determines the user-desired condition among the conditions in the change mode as the official collection saturation pulse setting based on the user's instruction. Specifically, for example, through the display control function 515, the processing circuit 51 displays each condition in the change mode and the corresponding spectrum on the display 55. The user selects the desired saturation pulse change mode. Through the decision function 516, the processing circuit 51 obtains this selection as a user instruction and determines the selected saturation pulse change mode as the official collection saturation pulse setting. Alternatively, through the decision function 516, the processing circuit 51 can select the condition of obtaining the saturation pulse with the least influence of fat as the official collection saturation pulse setting. That is, the condition of selecting the saturation pulse corresponding to the spectrum where the peak value of fat is below a threshold is selected as the official collection saturation pulse setting. As a reference for setting the saturation pulse, the saturation pulse can be set in the region as close as possible to the intended region of interest. In addition, the condition can be set to suppress the mixing of fat signals relative to the region of interest as much as possible and to have a small number of saturation pulses.

[0114] In step SC8, through the collection function 514, the processing circuit 51 applies a saturation pulse based on the formal collection saturation pulse setting, performs formal collection through the pulse sequence involved in formal collection, and collects the MRS signal.

[0115] Next, refer to Figure 6 An example of setting the change mode of the saturation pulse based on the second method will be explained.

[0116] Figure 6 This example involves defining a region of interest 31 on the MR image 30 of the subject P, and applying saturation pulses 61 to 63 around the region of interest 31. Here, as a variation mode, conditions are set for applying saturation pulses: applying one saturation pulse 61, applying two saturation pulses 61 and saturation pulse 62, and applying three saturation pulses 61, saturation pulse 62, and saturation pulse 63. Since a short collection time is desired during formal data collection, the condition with the fewest number of saturation pulses among those that suppress fat (i.e., the effect of fat relative to the spectrum is below a threshold) is determined for the formal collection saturation pulse setting, based on the spectrum of the MRS data collected under each condition.

[0117] Furthermore, when the collection method includes both the first method and the second method, the combined execution is performed. Figure 3 as well as Figure 5 The processing shown is sufficient. For example, simply execute the following... Figure 4 The combination shown is as follows: setting saturation pulse 61 in the first collection of interest regions 31-33, and setting saturation pulses 61-62 in the second collection of interest regions 31-33.

[0118] Further, in the above example, a case where a single voxel is set as the region of interest by the single voxel method is assumed, but the same processing can be applied in a case where collection is performed by the multi-voxel method related to a plurality of voxels.

[0119] In the multi-voxel method, since the region of interest exists inside the FOV (Field of View), it is sufficient to collect the magnetic resonance data multiple times while changing at least one of the collection region and the saturation pulse as described above, with the region of interest inside the FOV as a reference. Further, it is also possible to collect the magnetic resonance data multiple times for the above-described fat determination, with the region of the entire FOV as a reference.

[0120] Further, it is also possible to collect the magnetic resonance data multiple times for the above-described fat determination, with a region of an intermediate size between the FOV and the region of interest as a reference. For example, when a single voxel size of 1 x 1 is taken as a reference, in a case where the FOV is a voxel size of 12 x 12 and the region of interest is a voxel size of 4 x 4, a region of a voxel size of 8 x 8 can be taken as a reference as an intermediate size. Further, in a case of collection based on the multi-voxel method, it is also possible to perform the above-described determination processing with any region inside the FOV as a reference.

[0121] Next, a display example of the display control function 515 will be described with reference to Figure 7 and Figure 8 The display example of the display control function 515 will be described.

[0122] Figure 7 is a display example of a spectrum of a plurality of MRS signals based on the first method of collection. The left side is a spectrum 70 based on the MRS signal, and the right side is the position of the region of interest set on the MR image 30 corresponding to the spectrum 70. Here, for three spectra, the positions of the regions of interest 31 to 33 are displayed in correspondence, respectively. Further, the spectrum 70 and the MR image 30 in which the region of interest is specified can also be displayed in different windows. The user can select the position of the desired region of interest.

[0123] In addition, the maximum number of times of collection of the MRS signal and the number of times of collection indicating the current number of times of collection can also be displayed in correspondence with the spectrum 70 or the MR image 30 containing the region of interest.

[0124] Further, the search direction and the movement amount from the region of interest serving as a reference can also be displayed in correspondence with the spectrum 70 or the MR image 30 including the region of interest. In addition, the processing circuit 51 can display one spectrum 70 and the corresponding MR image 30 on a screen and display the spectrum of each region of interest or each collection condition in a manner capable of being dynamically switched by scrolling of a mouse or the like by the display control function 515. Thus, the user can dynamically confirm the change in the spectrum corresponding to the change in the position of the region of interest or the collection condition.

[0125] The displayed MR image 30 can be a cross-sectional image in which a region of interest is set. In the present embodiment, since the influence of fat on the spectrum is determined, in the case where a region of interest is specified in the top of the head, for example, if it is a sagittal cross section, a part of the left and right brains of the head, an MR image of a coronal cross section or a horizontal cross section can be displayed.

[0126] As Figure 7 indicated, the obtained spectrum 70 is different in each of the plurality of regions of interest. For example, in the upper drawing of Figure 7 , the fat tissue located around the region of interest is excited, the influence of fat is large, and the spectrum of the metabolite cannot be detected. On the other hand, in the lower drawing of Figure 7 , the influence of fat is small, and the spectrum of the metabolite can also be visually grasped. The user can determine the region of interest corresponding to the spectrum not mixed with fat as an official collection region of interest.

[0127] Next, Figure 8 is a display example of a plurality of MR data of a collection method based on the second method.

[0128] The left side is a spectrum 70 based on MRS data, and the right side is a set condition of a saturation pulse corresponding to the spectrum, which is displayed in correspondence with the MR image as saturation pulses 61 to 63. Here, the conditions of the saturation pulses are displayed in correspondence with the three spectra 70, respectively. As in the case of Figure 7 , the user can select the best official collection saturation pulse setting for the saturation pulse by referring to the spectrum 70.

[0129] Further, the spectrum and the condition of the region of interest or the saturation pulse shown in Figure 7 and Figure 8 may also be switched and displayed in real time at the time of each collection. For example, the processing circuit 51 displays the spectrum 70 of the upper drawing of Figure 7 after the collection of the MRS signal is completed by the display control function 515, and displays the spectrum 70 of the lower drawing of Figure 7 after the image processing. When the collection of the next MRS signal is completed, the spectrum 70 of the middle drawing of Figure 7 Figure 7 is switched.

[0130] Further, in a case where the spectrum is displayed in real time, the collection of the MR data can also be discontinued halfway in a case where the user determines that the desired spectrum has been obtained. For example, in a case where the spectrum with the desired spectrum is displayed, the currently displayed region of interest or the condition of the saturation pulse can be determined as the setting for the formal collection of the region of interest or the formal collection of the saturation pulse by pressing or clicking a prescribed button. In addition, in a case where the magnetic resonance data apparatus automatically determines the setting for the formal collection of the region of interest or the formal collection of the saturation pulse, for example, the region of interest or the saturation pulse corresponding to the spectrum in which the peak of the fat is less than one-tenth of the peak of the metabolite NAA can be selected. The processing circuit 51 displays the spectrum related to the selection by the display control function 515, and thus the user can easily visually confirm the shape of the spectrum, and thus can confirm the spectrum that is the basis for the determination.

[0131] Further, in the above example, it is assumed that the magnetic resonance data is data based on the MRS signal, but the present embodiment is not limited thereto.

[0132] For example, in the CEST (Chemical Exchange Saturation Transfer) method in which a trace amount of molecules is imaged using the exchange phenomenon between the protons within the molecules and the protons within the body water, the determination processing of the magnetic resonance data collection apparatus of the present embodiment can also be utilized in order to achieve the effect of suppressing the fat signal.

[0133] According to the present embodiment shown above, the generation section generates a pulse sequence for collecting the magnetic resonance data multiple times while changing at least one of the collection region and the setting condition of the saturation pulse with reference to the region of interest. The collection section collects a plurality of magnetic resonance data in accordance with the pulse sequence. Thereby, the position of the region of interest in which the mixing of the fat signal into the magnetic resonance data is reduced and the setting condition of the saturation pulse that can be utilized in the formal collection can be determined based on the spectrum based on the plurality of magnetic resonance data. In either a case where the user makes the determination or a case where the determination is made automatically by the apparatus, the position of the plurality of regions of interest or the setting condition of the saturation pulse can be determined while being compared with reference to the spectrum, and thus the dependence on the operator can be reduced and the influence of the fat signal on the spectrum can be reduced with high precision.

[0134] Further, the term "processor" used in the above description, for example, refers to a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or an ASIC (Application Specific Integrated Circuit) for a specific purpose, a programmable logic device such as a SPLD (Simple Programmable Logic Device), a CPLD (Complex Programmable Logic Device), and an FPGA (Field Programmable Gate Array), and the like. In the case where the processor is a CPU, the processor realizes the function by reading out and executing a program stored in a storage circuit. On the other hand, in the case where the processor is an ASIC, instead of storing a program in a storage circuit, the function is directly incorporated into the circuit of the processor as a logic circuit. Further, each processor of the present embodiment is not limited to the case where each processor is configured as a single circuit, and a plurality of independent circuits can be combined to configure one processor to realize the function. Furthermore, a plurality of components in the drawing can be combined into one processor to realize the function.

[0135] Further, each function of the present embodiment can also be realized by installing a program that executes the above-described processing to a computer such as a workstation and spreading them on a memory. At this time, the program that enables the computer to execute the above-described method can also be stored in a storage medium such as a disk (hard disk or the like), an optical disk (CD-ROM, DVD, or the like), a semiconductor memory, and the like to be distributed.

[0136] Several embodiments have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in other various ways, and various omissions, substitutions, modifications, and combinations of the embodiments with each other can be made within the scope of the gist of the invention. These embodiments or modifications thereof are included in the scope or gist of the invention, and are also included in the scope of the invention and equivalents thereof recited in the claims.

Claims

1. A magnetic resonance data collection apparatus comprising: an acquisition unit that acquires a specified region of interest; a generation unit that generates a pulse sequence for collecting magnetic resonance data multiple times while changing at least one of a collection region and a setting condition of a saturation pulse with reference to the region of interest; and a collection unit that collects a plurality of magnetic resonance data in accordance with the pulse sequence.

2. The magnetic resonance data collection apparatus according to claim 1, further comprising: a determination unit that determines a region of interest or a setting condition of a saturation pulse in which an influence of fat in a region to be collected is below a threshold value, based on the plurality of magnetic resonance data.

3. The magnetic resonance data collection apparatus according to claim 1, further comprising: a display control unit that controls to display at least one of the collection region and the setting condition of the saturation pulse changed by the generation unit and corresponding magnetic resonance data; and a determination unit that determines a region of interest or a setting condition of a saturation pulse in which an influence of a strong peak signal in a region to be collected is below a threshold value, based on one collection region or one setting condition of a saturation pulse selected by a user.

4. The magnetic resonance data collection apparatus according to claim 1, wherein the generation unit generates a pulse sequence for collecting magnetic resonance data multiple times while shifting a position of the region of interest along a specified search direction, and the plurality of magnetic resonance data are data corresponding to each position of the region of interest after the shift.

5. The magnetic resonance data collection apparatus according to claim 1, wherein the generation unit generates a pulse sequence for collecting magnetic resonance data multiple times while changing at least one of a position, an angle, and a number of the saturation pulse, and the plurality of magnetic resonance data are data corresponding to each condition of the saturation pulse after the change.

6. The magnetic resonance data collection apparatus according to claim 1, wherein the generation unit generates a pulse sequence in which a repetition time is shorter than in a case of formal collection, in a case of collecting the magnetic resonance data multiple times.

7. A magnetic resonance data collection method comprising: acquiring a specified region of interest; generating a pulse sequence for collecting magnetic resonance data multiple times while changing at least one of a collection region and a setting condition of a saturation pulse with reference to the region of interest; and collecting a plurality of magnetic resonance data in accordance with the pulse sequence.

8. A storage medium storing a magnetic resonance data collection program that causes a computer to function as: an acquisition function that acquires a specified region of interest; a generation function that generates a pulse sequence for collecting magnetic resonance data multiple times while changing at least one of a collection region and a setting condition of a saturation pulse with reference to the region of interest; and a collection function that collects a plurality of magnetic resonance data in accordance with the pulse sequence. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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