JP2004024918A - Method for scanning positioning for magnetic resonance, and magnetic resonance imaging equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for positioning scanning by which a voxel size can securely be decided while viewing without depending on tuition in magnetic resonance spectroscopy. <P>SOLUTION: The method for magnetic resonance positioning scanning sets one of a plurality of sheets of a tomogram as a standard image, displays the standard image, designates a two-dimensional area at a desired position on the standard image according to input from outside, and moreover, sets an ROI (region of interesting) passing through the two-dimensional area on the standard image according to input from outside. Furthermore, this method edits image data of a cross section passing through this ROI and orthogonal to the standard image from three-dimensional image data and displays the edited image data of the cross section as a reference image. Moreover, a range in a depth direction to the two-dimensional area is designated on the reference image according to the input from outside. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to scan positioning performed in an MR (magnetic resonance) apparatus, and more particularly, to appropriately setting a data acquisition area based on three-dimensional image data composed of a plurality of tomographic images of different slice positions of a subject. TECHNICAL FIELD The present invention relates to a magnetic resonance scan positioning method and a magnetic resonance imaging apparatus suitable for MR spectroscopy that can be set to the following.

Conventionally, a positioning scan in MRI includes a method using a light projector and a method using a reference image for positioning. Among these methods, the method using the reference image includes one-positioning using one reference image and two-positioning using two reference images.

In the single-sheet positioning scan, as shown in FIG. 18, one tomographic image (for example, an axial image) is used as a reference image, and an arbitrary linear position is set on this reference image using a linear ROI (region of interest): Ra. By designating, a slice plane that passes through the straight line position and perpendicular to the reference image can be designated. On the other hand, by designating a slice position that is parallel to the slice plane, imaging parallel to the slice plane can be designated. Here, the linear region of interest refers to a region in which a straight line position can be designated, and includes, for example, an elongated rectangular region of interest.

In the two-sheet positioning scan, as shown in FIG. 19, the first and second two parallel tomographic images (for example, axial images) are used as reference images, and each of the first and second images has a linear shape. By specifying a straight line position by the ROIs: Rb, Rc, the slice plane at the time of imaging is a cross section connecting the two ROIs: Rb, Rc. That is, the positioning is such that the slices can be sliced in any direction from the two parallel first and second images.

On the other hand, local excitation data collection in conventional magnetic resonance spectroscopy is performed by the ISIS method or the like. For the positioning of this data acquisition, one reference image (also referred to as a parent image) is prepared, a two-dimensional acquisition range is designated by a rectangular ROI on the reference image, and the range in the depth direction is directly manipulated by hand. A value was specified by input, and the voxel size was determined by this.

However, in both the single-image positioning and the two-image positioning described above, the portion that can be visually confirmed by the operator at the time of positioning is only the end of the slice surface at the time of actual imaging, and the slice surface to be actually imaged is I can't see it in advance. For this reason, for example, the operator must rely on intuition such that the image between the ROIs b and c in FIGS. 19A and 19B must rely on intuition. Become. Therefore, depending on the imaging result, it is necessary to perform positioning and imaging again, such as when the position of the lesion is shifted, and this often leads to a situation where the efficiency of the imaging operation is reduced. In order to prevent such a decrease in work efficiency, considerable experience and skill are required for the positioning skill of the operator.

Furthermore, when positioning by the above-described conventional method, even though the position of the slice plane at the time of imaging is directly displayed by the region of interest, the angle is not displayed in an illustration, so that the slice angle is set accurately. It was very difficult to do.

On the other hand, in the case of local excitation data collection in conventional spectroscopy, there is no problem because the reference image is displayed in the two-dimensional collection range, but the collection range in the depth direction must rely on intuition. For this reason, it is difficult to determine the exact voxel size, for example, a necessary part falls out of the voxel size or a part that is not to be collected is included in the voxel data a lot, which causes frequent data re-collection. And the collection time was long.

The present invention has been made in view of such a problem of the conventional method, and it is an object of the present invention to provide a magnetic resonance spectroscopy capable of accurately determining a voxel size visually without depending on intuition. And

In order to achieve the above object, according to one aspect of the present invention, there is provided a magnetic resonance imaging apparatus that determines a scan position using three-dimensional image data composed of data of a plurality of tomographic images prepared in advance of a diagnostic site of a subject. In the scan positioning method, a reference image setting step of setting one of the plurality of tomographic images as a reference image, a reference image display step of displaying the reference image, and the reference image in response to an external input A two-dimensional area designating step of designating a two-dimensional area at a desired position above, an ROI setting step of setting an ROI passing through the two-dimensional area on the reference image according to an external input, and A cross-section editing step of editing image data of a cross section orthogonal to the reference image from the three-dimensional image data; and A reference image display step of displaying Te, characterized in that it comprises a and a depth range specifying step of specifying the depth direction of the range for the two-dimensional region on the reference image in response to an input from the outside.

According to another aspect of the present invention, there is provided a magnetic resonance apparatus configured to determine a scan position using three-dimensional image data including data of a plurality of tomographic images prepared in advance of a diagnostic site of a subject. An imaging device is provided. The magnetic resonance imaging apparatus includes: a reference image setting unit that sets one of the plurality of tomographic images as a reference image; a reference image display unit that displays the reference image; A two-dimensional region designating unit for designating a two-dimensional region; a ROI setting unit for setting an ROI passing through the two-dimensional region on the reference image; and an image data of a cross section passing through the ROI and orthogonal to the reference image. Cross-section editing means for editing from three-dimensional image data, reference image display means for displaying the image data of the edited cross-section as a reference image, and a depth for specifying a range in the depth direction for the two-dimensional area on the reference image. And a range designating means.

According to the magnetic resonance scan positioning method and the magnetic resonance imaging apparatus according to the present invention, the cross-sectional image (reference image) including the actual affected part can be determined without depending on the voxel size of local excitation data acquisition in magnetic resonance spectroscopy. You can also set the collection range in the depth direction while watching. That is, the voxel size can be more accurately determined by visual confirmation. As a result, the collection time can be kept to a necessary minimum, and the number of times of collection is reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(1st Embodiment)
1st Embodiment is described based on FIGS.

The magnetic resonance imaging apparatus shown in FIG. 1 includes a magnet unit for generating a static magnetic field, a gradient magnetic field unit for generating a gradient magnetic field for giving positional information to the static magnetic field, and transmission / reception for magnetic excitation and reception of NMR signals. Unit and a control / calculation unit.

Specifically, the magnet unit includes, for example, a superconducting magnet 1 and a static magnetic field power supply 2 for supplying a current to the magnet 1, and generates a static magnetic field H0 in the z-axis direction of the opening where the subject P enters. Let it. The gradient magnetic field section includes three pairs of gradient magnetic field coils 4... 4 (only some of which are shown) in the x, y, and z directions incorporated in the magnet 1 and supplies current to these gradient magnetic field coils 4. And a gradient magnetic field power supply comprising a gradient magnetic field control device 6. The gradient magnetic field control device 6 operates the drive circuit 5 according to the pulse sequence supplied from the main control device 7. Accordingly, in order to impart positional information for imaging, by superimposing a linear magnetic field in the static magnetic field H _0, the gradient magnetic field is formed. The transmission / reception unit includes a transmission coil 8a and a reception coil 8b disposed facing the subject P in the opening of the magnet 1, and a transmitter 9 individually connected to the transmission coil 8a and the reception coil 8b. And a receiver 10. The transmitter 9 generates a high-frequency pulse for exciting the NMR based on a command from the control device 7. The receiver 10 detects and amplifies the NMR signal obtained by the coil 8b, and sends the NMR signal to the storage device 11 based on a command from the control device 7.

Further, the control / arithmetic unit gives an operation command to the control device 7 connected to the transmitter 9, the receiver 10, and the gradient magnetic field control device 6, a storage device 11 for storing NMR signals, and the control device 7. , A processing device 12 for processing a storage signal of the storage device 11, and a display device 13 for display. An input device 14 such as a keyboard is connected to the arithmetic unit 12. The arithmetic unit 12 generates image data by subjecting the acquired NMR signal to an enormous amount of arithmetic processing including Fourier transform. This image data is displayed on the display device 13 as needed.

The procedure shown in FIG. 2 which can control from the positioning to the main scan is stored as one of the fixed data in the storage device 11, and the procedure is called in the work area of the arithmetic unit 12 when the system is started. And the process is started.

Next, the operation and effect of this embodiment will be described with reference to FIGS.

First, when the setup and registration of the patient are completed and the system is started, the processing shown in FIG.

In step 20 of FIG. 2, first, for example, a command for multi-slice imaging is sent to the control device 7, and a plurality of different positions of the affected part are continuously sliced by a pulse sequence commanded by the control device 7. IM1... IMn are obtained as shown in FIG. That is, three-dimensional image data of the affected part for positioning is obtained.

Next, in step 21, one tomographic image IMi of the plurality of tomographic images IM1... IMn is designated as a reference image for positioning. This designation is made based on the position information designated by the operator via the input device 14, but it is also possible to designate a tomographic image at a preset position (for example, the tomographic image IM1 at the head position) as the reference image. Good. Next, the processing shifts to the processing of step 22, and the designated reference image IMi is displayed on the TV monitor of the display device 13, for example, as shown in FIG.

Therefore, in step 23, the operator gives two linear ROIs (regions of interest): Rd and Re (first linear ROIs) from the input device 14 so that two linear ROIs are displayed on the image of the TV monitor. The position is designated, for example, as shown in FIG. Here, of the linear ROIs: Rd, Re, one ROI: Rd specifies the cross section in the horizontal direction of the reference image IMi as viewed from the operator, and the other ROI: Re is orthogonal to the previous ROI: Rd. The vertical section is specified. However, the two ROIs: Rd and Re may be specified to be oblique to each other.

Next, proceeding to step 24, the arithmetic unit 12 assumes two cross sections orthogonal to the reference image IMi through the linear position specified by ROI: Rd, Re, and corresponds to each pixel forming the two cross sections. The image data to be edited is edited from the three-dimensional image data described above. Next, in step 25, the image data of the two orthogonal cross sections edited in step 24 are separately displayed as a cross-sectional image IMx and a vertical cross-sectional image IMy (reference image) as shown in FIG.

Next, the process proceeds to step 26, where elongated rectangular ROIs: Rf and Rg (second linear ROIs) are designated by the operator on the horizontal sectional image IMx and the vertical sectional image IMy, respectively, as shown in FIG. That is, the operator specifies the straight line positions of the cross-sectional image IMx and the vertical cross-sectional image IMy so that the cross-section passing through the ROIs: Rf and Rg becomes the cross-section to be scanned while viewing the cross-sectional image IMx and the vertical cross-sectional image IMy.

Next, in step 27, it is determined whether or not the cross section passing through the ROIs: Rf, Rg is twisted. If there is a twist, a message is displayed in step 28 indicating that the image data cannot be collected as described below because of the twist. In this case, the process returns to step 26 again to reset the ROIs: Rf and Rg.

場合 If there is no such twist, then go to step 29. In step 29, the image data corresponding to the pixel of the cross section passing through the straight line positions of the two ROIs: Rf and Rg set in step 26 is edited from the above-described three-dimensional image data. For example, a slice section that passes straight through two ROIs: Rf and Rg, both of which are oblique and designated in FIG. 4D, has the head obliquely in the front-back direction and the left-right direction as shown in FIG. Obtains a sliced, twist-free oblique image. That is, depending on the set angles of the two ROIs: Rf and Rg, not only the axial image, the sagittal image, and the coronal image but also the position of the oblique image (oblique image without twist) at any angle can be freely specified.

(4) In step 30, the image IMob of the image data edited in step 29 is divided and displayed as shown in FIG. As a result, an oblique image having the same cross-section (not actually sliced) as sliced as shown in FIG. 5 is obtained as a predicted image IMob at the time of scanning on the divided screen. This predicted image IMob has a meaning that when a cross section specified by the two ROIs: Rf and Rg is actually scanned, it is photographed as such, and an approximate scan screen is provided to the operator in advance. Is what you do. As described above, since the prediction screen IMob is formed by re-editing the three-dimensional image data once photographed as described above, the amount of diagnostic information is lower than the original image data, but the morphological information is still lower. A screen having considerable accuracy and including slice angle information can be provided to the operator.

For this reason, the operator visually checks the predicted image IMob in step 31 and determines whether or not the currently displayed predicted image is good. If the image is good (OK), the cross-sectional position of the predicted image (ie, , A slice plane position), and in step 33, an actual scan is performed. If it is determined in step 31 that the positioning needs to be corrected, the process returns to step 21 and the above-described processing may be repeated.

As described above, this embodiment utilizes the processing technology of the cross-section conversion processing (MPR), and the state of the cross-section to be actually photographed can be visually checked in advance. Disappears. In addition, when the predicted image is not the desired image, it can be easily reset before the actual scan is performed. For this reason, the skill required of the operator is eased, and the positioning operation is facilitated. On the other hand, the entire operation from the positioning to the scanning has to be performed again due to a positioning error or the like. Is greatly reduced, so that the total throughput of the positioning scan in MRI is remarkably improved.

{Circle around (2)} In particular, a method of displaying a predicted image sequentially through a two-dimensional reference image and a reference image, and not a method of directly processing three-dimensional image data. Thus, in the present embodiment, the calculation load applied to the calculation device at one time can be reduced, and the ROI setting can be visually and sequentially performed without any doubt as to which cross section to look at first. By specifying a slice plane with high accuracy, a predicted image can be obtained.

On the other hand, in the above-described embodiment, the processing steps of specifying the first linear ROIs: Rd and Re to obtain the cross-sectional image IMx and the vertical cross-sectional image IMy, respectively (see FIGS. 4B and 4C) The process for setting the second ROI: Rf, Rg (see FIG. 4D) is equivalent to the conventional single-sheet positioning, and the conventional two-sheet positioning technique is applied. For this reason, processing equivalent to the conventional one-sheet positioning and two-sheet positioning can also be easily executed (in the case of one-sheet positioning, for example, only a cross-sectional view is displayed, and in the case of two-sheet positioning, the reference is made. This is limited to designating two parallel ROIs: Rd and Re in the image IMi), and a system that controls the entire positioning in the positioning scan can be developed.

構成 Functional components and processes in the above embodiment are as follows. The process of step 21 in FIG. 2 forms the main part of the reference image setting means, the process of step 22 in FIG. 2 forms the main part of the first display means, and the process of step 23 in FIG. The main part of the ROI setting means is formed. Also, the processing of steps 24, 25, and 26 in FIG. 3 form the main parts of the first image data editing means, the second display means, and the second ROI setting means, respectively. Furthermore, the processing of step 27 in FIG. 17 forms a twist determining means, and the processing of steps 29 and 30 form the main parts of the second image data editing means and the third display means, respectively. Further, the processing in step 31 in FIG. 14 forms an image determining unit, and the processing in step 32 in FIG. 14 forms a unit for providing the position of the diagnostic site corresponding to the predicted image to the scan plan. FIG. 6 shows the connection between these means.

In the first embodiment, when the reference image is displayed (step 22), whether or not the reference image is desired, and when the cross-sectional image as the reference image is displayed (step 25), It is determined whether or not the reference image is the desired image. If the image is the desired image, the process proceeds to the next step. If not, the above process may be performed again. This makes it possible to check the images one by one in the course of displaying the predicted image, which is convenient.

(2nd Embodiment)
A second embodiment will be described with reference to FIGS. In the following embodiments, the same components as those in the above-described first embodiment will be denoted by the same reference numerals, and description thereof will be omitted or simplified.

In the second embodiment, instead of limiting the setting method of the two first linear ROIs and the two second linear ROIs used in the first embodiment, the twist judgment is not required. It is.

The hardware configuration of the magnetic resonance imaging apparatus according to the second embodiment is the same as that of the first embodiment, and the arithmetic unit 12 executes a series of positioning scan processes shown in FIG.

In the process of FIG. 7, first, the processes of steps 40 to 42 are sequentially performed. These processes are the same as steps 20 to 22 in FIG. 2 described above. Thereby, one of the tomographic images constituting the three-dimensional image data IM1... IMn of the affected part is displayed on the display device 13 as the reference image IMi (for example, an axial image of the head) (see FIG. 8A).

Next, in step 43, it is determined whether or not the designation of the reference image IMi is sufficient by reading the operation information from the operator provided through the input device 14. If the user wants to change the reference image to another one (NO), the process returns to step 41 and the designation operation is repeated. When the reference image IMi can be specified (YES), the processing of steps 44 to 46 is sequentially performed.

In step 44, two parallel elongated first ROIs R1a and R1b are set at desired positions on the reference image IMi based on the ROI designation signal from the operator. The first ROIs R1a and R1b are set obliquely and parallel on an axial image as the reference image IMi, for example, as shown in FIG.

Next, at step 45, data of two orthogonal sections passing through the position specified by the first ROI: R1a, R1b and orthogonal to the reference image IMi are converted into three-dimensional image data in the same manner as at step 24 of FIG. Edited from. Accordingly, in step 46, the edited image data of the two orthogonal cross sections is individually displayed as reference images IMa and IMb. The reference images IMa and IMb are, for example, tomographic images obtained by slicing the head vertically at the positions of the first ROIs: R1a and R1b, as shown in FIG. 8C.

Next, the arithmetic unit 12 shifts the processing to step 47. In step 47, it is determined whether or not the reference images IMa and IMb are desired based on operation information from the operator. If not (NO), the flow returns to step 44 to return to the first ROI: R1a and R1b can be reset. If the reference images IMa and IMb are the desired ones (YES), the processing of steps 48 to 50 is performed.

Of these, in step 48, based on the ROI designation information from the operator, as shown in FIG. 8D, two elongated rectangular second ROIs: R2a and R2b are set in the reference images IMa and IMb, respectively. You. Here, when the slice directions of the reference images IMa and IMb are aligned, the second ROIs R2a and R2b are set to be parallel to each other.

Further, in Steps 49 and 50, similarly to Steps 29 and 30 in FIG. 2 described above, the image data of the cross section connecting the second ROIs: R2a and R2b is edited, and a predicted image IMob is generated based on the image data in FIG. It is displayed as shown in (e). Thus, an oblique image at an arbitrary angle as well as an axial surface, a sagittal surface, and a coronal surface is provided as the predicted image IMob.

(4) Next, in step 51, it is determined whether or not the displayed predicted image IMob has a desired cross section. If the operator wants to display another predicted image (NO), the process returns to step 48 to reset only the second ROIs: R2a and R2b. If the currently displayed predicted image IMob is acceptable (YES), the processing of steps 52 and 53 is performed. In step 52, as in the first case, a scan plan such as the number of slices and imaging conditions is made, and in step 53, a scan based on the scan plan is performed.

As described above, the same effects as those of the first embodiment can be obtained by the second embodiment. In addition, by setting the first ROIs: R1a and R1b and the second ROIs: R2a and R2b in parallel with each other, a predicted image can be obtained. It is not necessary to determine whether or not the cross section is twisted, and the processing is simplified. In the middle of a series of positioning, whether the reference image IMi is sufficient (step 43 in FIG. 7), whether the reference images IMa and IMb are appropriate (step 47 in FIG. 7), and whether the prediction image IMob is appropriate (FIG. 7). Since the judgment in step 51) has been made, the process proceeds while checking each image. In the present embodiment, even when the final predicted image IMob is changed to another one, it is possible to start over from the reference images IMa and IMb, and the change is facilitated.

In the second embodiment, a configuration in which some or all of the determination steps of steps 43, 47, and 51 are omitted is also possible.

(Third embodiment)
A third embodiment will be described with reference to FIGS. In the third embodiment, the number of the first linear ROI and the number of the second linear ROI used in the second embodiment are each one.

The hardware configuration of the magnetic resonance imaging apparatus according to the third embodiment is the same as that of the first embodiment, and the arithmetic unit 12 executes a series of positioning scan processes shown in FIG.

In the process of FIG. 9, first, the processes of steps 60 to 63 are sequentially performed. These processes are the same as steps 40 to 43 in FIG. Thus, the reference image IMi (for example, an axial image of the head) is displayed on the display device 13 and determined (see FIG. 10A).

Next, in step 64, the first elongated ROI R1: R1 is set at a desired position on the reference image IMi based on the ROI designation signal from the operator (see FIG. 10B). Next, in step 65, data of one orthogonal cross section passing through the position specified by the first ROI: R1 and orthogonal to the reference image IMi is edited from the three-dimensional image data. Thus, in step 66, the edited image data of the orthogonal cross section is displayed as the reference image IMref (see FIG. 10C).

Next, in step 67, it is confirmed whether or not the reference image IMref is sufficient as in the second embodiment.

Thereafter, the process proceeds to step 68, and based on the ROI designation signal from the operator, as shown in FIG. 10D, the second rectangular ROI: R2 having an elongated rectangular shape is set at an arbitrary position on the reference image IMref. Is done.

Therefore, in the next step 69, the image data of the cross section passing through the position of the second ROI: R2 and orthogonal to the reference image IMref is edited from the three-dimensional image data. In step 70, a predicted image IMob is displayed based on the image data as shown in FIG. Thereby, an oblique image at an arbitrary angle as well as the axial surface, the sagittal surface, and the coronal surface is provided as the predicted image IMob.

(5) Next, in step 71, it is confirmed whether or not the displayed predicted image IMob has a desired cross section. Next, a scan plan is made by the processing of steps 72 and 73, and a scan based on the scan plan is performed.

As described above, in the third embodiment, since the first and second ROIs R1 and R2 are each one, the setting of the ROI is simplified and the data processing is also simplified. Further, the number of reference images in the process of obtaining the final predicted image IMob is smaller than that in the first and second embodiments, and tomographic image information for positioning is reduced by that amount, but this can withstand positioning. An accurate prediction image can be obtained. Further, similarly to the second embodiment, the positioning can be advanced while confirming the reference image IMi, the reference image IMref, and the predicted image IMob each time, and a reliable positioning scan can be executed. Furthermore, when it is desired to change the final predicted image IMob to another one, the change is easy.

(Fourth embodiment)
A fourth embodiment will be described with reference to FIGS. The fourth embodiment is different from the above-described embodiment in that the number of positioning processes is reduced from two to one.

The hardware configuration of the magnetic resonance imaging apparatus according to the fourth embodiment is the same as that of the first embodiment, and the arithmetic unit 12 executes the positioning scan processing shown in FIG.

処理 The processing in steps 80 to 85 in FIG. 11 is the same as the processing in steps 60 to 65 in FIG. 9 according to the third embodiment. That is, one ROI: R1 is set in an arbitrary direction on the reference image IMi (see FIGS. 12A and 12B), and image data of a cross section passing through the ROI: R1 and orthogonal to the reference image IMi is obtained. Edited.

Next, in step 86, the image data edited in step 85 is directly displayed as the predicted image IMob (see FIG. 12C).

後 Thereafter, the processing of steps 87 to 89 is performed in the same manner as in the above-described embodiments.

According to the fourth embodiment, a cross-sectional image orthogonal to the reference image can be predicted and displayed, and the process of generating the predicted image is significantly shortened as compared with the above-described embodiments. There is an advantage that there is.

In this embodiment, the processing of step 80 in FIG. 11 forms the main part of the image data preparation means, the processing of step 81 in FIG. 11 forms the main part of the reference image setting means, and the processing of step 82 in FIG. The main part of the image display means is formed, and the processing of step 84 in the figure forms the main part of the ROI setting means. Also, the processing of steps 85 and 86 in the figure form the main parts of the image data editing means and the predicted image display means, respectively. Further, the processing of step 87 in FIG. 9 forms an image determining means, and the processing of step 88 in FIG. 11 forms means for providing the position of the diagnostic site corresponding to the predicted image to the scan plan. FIG. 13 shows the connection between these means.

(Fifth embodiment)
A fifth embodiment will be described with reference to FIGS. In the fifth embodiment, two reference images are used while the process for positioning is one stage.

The hardware configuration of the magnetic resonance imaging apparatus according to the fifth embodiment is the same as that of the first embodiment, and the arithmetic unit 12 executes the positioning scan processing shown in FIG.

When the process in FIG. 14 starts, three-dimensional image data is obtained in step 90. Next, the routine proceeds to step 91, where two desired tomographic images IMi and IMj are designated as reference images from a plurality of tomographic images IM1... IMn forming three-dimensional image data (for example, the first and last axial images). Image is specified). The two designated reference images IMi and IMj are displayed in the next step 92 (see FIG. 15A). In step 93, it is determined whether or not these two reference images IMi and IMj are satisfactory.

When the two reference images IMi and IMj are determined, two elongated rectangular ROIs R1a and R1b are set on the reference images IMi and IMj in step 94 (see FIG. 15B). At this time, the ROIs R1a and R1b are set in parallel. In step 95, the image data of the cross section connecting the two ROIs: R1a and R1b is edited from the three-dimensional image data. Further, in step 96, the image data of the cross section is directly displayed as a predicted image IMob as shown in FIG.

Next, the processing of steps 97 to 99 is performed similarly.

According to the fifth embodiment, it is possible to predict and display an arbitrary cross section including an oblique image other than an image of a cross section in the same direction as the reference image, and also to obtain cross section information because the number of reference images is larger than in the fourth embodiment. As a result, it is possible to obtain a more accurate predicted image while performing simple one-stage positioning.

(Sixth embodiment)
A sixth embodiment will be described with reference to FIGS. The sixth embodiment is applied to voxel data collection of magnetic resonance spectroscopy.

The hardware configuration of the spectroscopy magnetic resonance imaging apparatus according to the sixth embodiment is the same as that of the first embodiment, and the arithmetic unit 12 executes the positioning scan processing shown in FIG.

When the process of FIG. 16 starts, the processes of steps 100 to 103 are sequentially performed. This processing is the same as in each of the above-described embodiments. Thus, for example, as shown in FIG. 17A, an axial image of the head is displayed as the reference image IMi.

(4) After the reference image IMi is determined in step 103, the process proceeds to step 104, where a two-dimensional collection range is set on the reference image IMi by a rectangular ROI: Rrec (see FIG. 17B).

Next, the routine proceeds to step 105, in which the linear ROI: Rn formed by the line ROI or the elongated rectangular ROI is used, and the linear ROI: Rn is set to pass through the rectangular ROI: Rrec (FIG. 17 (c-1)). Or (c-2): as in this example, the linear ROI: Rn may pass vertically or horizontally through the rectangular ROI: Rrec, or may pass obliquely.

Next, in step 106, the image data of the cross section passing through the linear ROI: Rn and orthogonal to the reference image IMi is edited from the three-dimensional image data. The image of this orthogonal cross section is displayed in step 107 (see FIG. 17 (d-1) or (d-2)). Thereafter, in step 108, it is determined whether or not the displayed orthogonal cross-sectional image IMtm (reference image) is a desired one based on operation information from an operator. Returning to the processing, the setting of the linear ROI is redone.

と き If the determination in step 108 is the desired one (YES), the process proceeds to step 109. In step 109, a range in the depth direction is set by the ROI on the displayed orthogonal cross-sectional image IMtm. For example, as shown in FIG. 17 (e-1), the affected part may be sandwiched between two lines ROI: Rm1 and Rm2, and the range in the depth direction may be set, or as shown in FIG. 17 (e-2). As described above, the range in the depth direction may be set by two points ROI: Rs1 and Rs2.

When the two-dimensional acquisition range and the depth direction range are determined in this way, a scan plan based on the information is set in step 110, and local excitation data collection is performed in step 111 by, for example, the ISIS method.

As described above, the acquisition range in the depth direction can be set while observing the cross-sectional image (reference image) including the actual affected part without depending on the voxel size of the local excitation data acquisition in the magnetic resonance spectroscopy. That is, the voxel size can be more accurately determined by visual confirmation. As a result, the collection time can be kept to a necessary minimum, and the number of times of collection is reduced.

FIG. 1 is a block diagram of a magnetic resonance imaging apparatus according to an embodiment of the present invention. 4 is a schematic flowchart illustrating positioning according to the first embodiment. FIG. 3 is an explanatory diagram illustrating a configuration of three-dimensional image data. (A)-(e) is explanatory drawing explaining the mode of the divided screen along the positioning procedure. FIG. 4 is an explanatory diagram illustrating an example of a cross-sectional position of an oblique image obtained by positioning. Claim correspondence diagram of the magnetic resonance imaging apparatus of the invention of claims 14-17. 9 is a schematic flowchart illustrating positioning according to the second embodiment. (A)-(e) is an image figure explaining the positioning procedure in 2nd Embodiment. 9 is a schematic flowchart illustrating positioning according to the third embodiment. (A)-(e) is an image figure explaining the positioning procedure in 3rd Embodiment. 14 is a schematic flowchart illustrating positioning according to the fourth embodiment. (A)-(c) is an image figure explaining the positioning procedure in 4th Embodiment. Claim correspondence diagram of the magnetic resonance imaging apparatus of the invention according to claims 12 and 13. 15 is a schematic flowchart illustrating positioning according to the fifth embodiment. (A)-(c) is an image figure explaining the positioning procedure in 5th Embodiment. 16 is a schematic flowchart illustrating positioning according to the sixth embodiment. (A)-(e-1), (e-2) is an image figure explaining the positioning procedure in 6th Embodiment. Explanatory drawing explaining the conventional one-sheet positioning. Explanatory drawing explaining the conventional two-sheet positioning.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Magnet 2 Static magnetic field power supply 4 Gradient magnetic field coil 5 Drive circuit 6 Gradient magnetic field control device 7 Control device 8a, 8b Transmitting coil and receiving coil 9 Transmitter 10 Receiver 11 Storage device 12 Operation device 13 Display device 14 Input device

Claims (2)

In a magnetic resonance scan positioning method for determining a scan position using three-dimensional image data composed of data of a plurality of tomographic images prepared in advance of a diagnostic site of a subject,
A reference image setting step of setting one of the plurality of tomographic images as a reference image, a reference image display step of displaying the reference image, and a desired position on the reference image in response to an external input. A two-dimensional region designating step of designating a two-dimensional region; a ROI setting step of setting an ROI passing through the two-dimensional region on the reference image in response to an external input; A cross-section editing step of editing the image data of the cross-section to be performed from the three-dimensional image data, a reference image display step of displaying the edited cross-section image data as a reference image, and A depth range designation step of designating a range in the depth direction with respect to the two-dimensional region. In a magnetic resonance imaging apparatus configured to determine a scan position using three-dimensional image data composed of data of a plurality of tomographic images prepared in advance of a diagnostic site of a subject,
Reference image setting means for setting one of the plurality of tomographic images as a reference image, reference image display means for displaying the reference image, and designating a two-dimensional area at a desired position on the reference image. Dimensional area designating means, ROI setting means for setting an ROI passing through the two-dimensional area on the reference image, and editing image data of a cross section passing through the ROI and orthogonal to the reference image from the three-dimensional image data Cross-section editing means, reference image display means for displaying the image data of the edited cross-section as a reference image, and depth range specification means for specifying a range in the depth direction with respect to the two-dimensional area on the reference image. A magnetic resonance imaging apparatus comprising:

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