Magnetic Resonance Imaging Apparatus and Magnetic Resonance Imaging Method

Abstract

A magnetic resonance imaging apparatus and a magnetic resonance imaging method capable of improving the imaging direction consistency between oblique images with the same type of oblique position and different imaging protocols. The magnetic resonance imaging apparatus of the present invention includes: an image acquisition unit that acquires three-dimensional volume data of a pilot image that is easy to identify anatomical structures for an imaging region of a subject; a geometric parameter generation unit that generates geometric parameters including the imaging direction of the oblique image based on feature points detected from the three-dimensional volume data of the pilot image; an oblique image determination unit that determines the imaging protocol of the oblique image and the type of oblique position corresponding to each imaging protocol according to an examination instruction for the imaging region; and an oblique image generation unit that generates multiple types of oblique images corresponding to the determined imaging protocol and the type of oblique position using the geometric parameters for one or more formal three-dimensional volume data acquired by the image acquisition unit.

Description

Technical Field

[0001] Embodiments of the present invention relate to a magnetic resonance imaging apparatus and a magnetic resonance imaging method. Background Art

[0002] When obtaining medical images by a magnetic resonance imaging apparatus, for different body parts, it is usually necessary to obtain oblique images suitable for observing each body part.

[0003] Oblique images can be classified into multiple oblique types such as oblique sagittal, oblique coronal, and oblique axial according to the imaging direction, and the uses of each oblique type are also different. Taking the knee as an example, an oblique sagittal image parallel to the outer edge of the femoral condyle is suitable for observing the posterior cruciate ligament (PCL), and both an oblique sagittal image parallel to the line passing through multiple epicondyles and an oblique coronal image are suitable for observing the anterior cruciate ligament (ACL). The oblique axial image can clearly depict the anteromedial bundle (AM bundle) and the posterolateral bundle (PL bundle) of the anterior cruciate ligament, and can separately evaluate the anteromedial bundle and the posterolateral bundle.

[0004] In addition, when using a magnetic resonance imaging apparatus to obtain oblique images, depending on the imaging site and imaging purpose, one or more of multiple imaging protocols including T1 weighted image (T1WI), T2 weighted image (T2WI), proton density weighted image (PDWI), fluid attenuated IR (FLAIR), diffusion weighted image (DWI), and perfusion weighted image (PWI) are usually used to obtain the oblique image of the target imaging site.

[0005] Conventionally, there has been a magnetic resonance imaging apparatus that directly obtains a two-dimensional image as an oblique image. In such a magnetic resonance imaging apparatus, it is usually necessary to separately obtain oblique images of different oblique types for each predetermined imaging protocol. Therefore, the number of imaging times of the oblique images is the sum of the numbers of oblique types corresponding to each imaging protocol. Assuming that there are 3 imaging protocols to be executed for a certain body part and 2 oblique types corresponding to each imaging protocol, then the total number of imaging times of the oblique images is 6 times in total, which will result in an excessively long total imaging time of the oblique images.

[0006] In addition, there is also a medical image processing apparatus that obtains three-dimensional volume data and performs post-processing to generate oblique images. In such a medical image processing apparatus, for different three-dimensional volume data corresponding to different imaging protocols, feature points (landmarks) are respectively detected, and imaging geometric parameters such as the imaging direction and the field of view (FOV) of the oblique image are determined based on the detected feature points, and then one or more oblique images of the oblique types corresponding to the imaging protocol are generated.

[0007] However, when detecting feature points for different three-dimensional volume data, since the feature points that can be obtained by different imaging protocols are different, there are cases where it is difficult to detect the desired feature points in the three-dimensional volume data of some imaging protocols. As a result, the imaging directions of the oblique images generated for different imaging protocols may be different, and there is a problem of inconsistent imaging directions between oblique images with the same oblique type and different imaging protocols. SUMMARY OF THE INVENTION

[0008] In view of the problems existing in the prior art, the present invention provides a magnetic resonance imaging apparatus and a magnetic resonance imaging method, which can improve the consistency of the imaging directions between oblique images with the same oblique type and different imaging protocols.

[0009] The magnetic resonance imaging apparatus of the present invention is characterized in that it has: an image acquisition unit that acquires leading image three-dimensional data that is easy to identify anatomical structures for an imaging part of a subject; a geometric parameter generation unit that generates geometric parameters including the imaging direction of an oblique image based on feature points detected from the leading image three-dimensional data; an oblique image determination unit that determines an imaging protocol of the oblique image and the oblique types corresponding to each of the imaging protocols according to an examination instruction for the imaging part; and an oblique image generation unit that generates multiple types of oblique images corresponding to the determined imaging protocol and the oblique types for one or more formal three-dimensional data acquired by the image acquisition unit by using the geometric parameters.

[0010] In the magnetic resonance imaging device, the geometric parameters include one or more imaging direction parameters, and the one or more imaging direction parameters respectively correspond to one or more of the oblique plane types. For each formal three-dimensional volume data respectively corresponding to each imaging protocol, the oblique plane image generation unit uses the geometric parameters including the imaging direction parameters to generate one or more oblique plane images of the oblique plane types corresponding to the imaging protocol.

[0011] In the magnetic resonance imaging device, the geometric parameters further include one or more imaging position parameters, and the one or more imaging position parameters respectively correspond to the one or more imaging direction parameters. Each imaging position parameter includes information indicating the center point of the imaging field of view and the imaging range.

[0012] In the magnetic resonance imaging device, a geometric parameter conversion unit is further included. Before generating the oblique plane images, the geometric parameter conversion unit respectively performs image registration on the acquired preliminary image three-dimensional volume data and one or more formal three-dimensional volume data, and based on the result of the image registration, converts the geometric parameters into one or more sets of geometric parameters respectively corresponding to the one or more formal three-dimensional volume data. The oblique plane image generation unit uses the converted geometric parameters and the formal three-dimensional volume data to generate the multiple types of oblique plane images.

[0013] In the magnetic resonance imaging device, the preliminary image three-dimensional volume data is three-dimensional volume data acquired using an imaging protocol that can easily identify the anatomical structure of the imaging part.

[0014] In the magnetic resonance imaging device, the oblique plane types include at least one of an oblique coronal plane, an oblique sagittal plane, and an oblique transverse plane, and the imaging protocols include at least one of a longitudinal relaxation weighted image, a transverse relaxation weighted image, a proton density image, a fluid-attenuated inversion recovery image, a diffusion weighted image, and a perfusion weighted image.

[0015] The magnetic resonance imaging method of the present invention is characterized by including: a preliminary image acquisition step of acquiring preliminary image three-dimensional volume data that can easily identify the anatomical structure for the imaging part of the subject; a geometric parameter generation step of generating geometric parameters including the imaging direction of the oblique plane image according to the feature points detected from the preliminary image three-dimensional volume data; an oblique plane image determination step of determining the imaging protocol of the oblique plane image and the oblique plane types corresponding to each imaging protocol according to the examination instruction for the imaging part; a formal image acquisition step of acquiring one or more formal three-dimensional volume data for the imaging part; and an oblique plane image generation step of using the geometric parameters to generate multiple types of oblique plane images corresponding to the determined imaging protocol and the oblique plane types for the one or more acquired formal three-dimensional volume data.

[0016] In the magnetic resonance imaging method, before the oblique image generation step, a geometric parameter conversion step is further included. In the geometric parameter conversion step, the acquired pilot image three-dimensional volume data is respectively subjected to image registration with one or more formal three-dimensional volume data, and based on the result of the image registration, the geometric parameters are converted into a set of geometric parameters respectively corresponding to one or more formal three-dimensional volume data. In the oblique image generation step, using the converted geometric parameters and the formal three-dimensional volume data, multiple types of oblique images corresponding to the oblique type and the imaging protocol are generated.

[0017] Advantages of the Invention

[0018] According to the magnetic resonance imaging apparatus and the magnetic resonance imaging method configured as described above, since the same geometric parameters are used to generate oblique images of the imaging region for different imaging protocols, multiple types of oblique images with consistent imaging directions can be automatically generated. Even for imaging protocols where feature points are not easily detected, oblique images with imaging directions consistent with those of other imaging protocols can be generated.

[0019] In addition, compared with a magnetic resonance imaging apparatus that directly acquires two-dimensional images as oblique images, the present invention only needs to acquire three-dimensional volume data once for each imaging protocol, and can significantly shorten the time required for imaging all oblique images.

[0020] In addition, through the conversion process performed by the geometric parameter conversion unit, multiple sets of geometric parameters that are more matched with each formal three-dimensional volume data are generated based on the same geometric parameters, and then multiple types of oblique images are generated. Thereby, the imaging direction error caused by the differences between the three-dimensional volume data is further eliminated, and multiple types of oblique images with more consistent imaging directions can be automatically generated. Especially when the imaging region is the chest, heart, abdomen, etc., since the imaging region changes with breathing or pulsation, the imaging direction consistency between multiple types of oblique images can be significantly improved by performing the geometric parameter conversion process. Description of the Drawings

[0021] Figure 1 is a functional block diagram showing a magnetic resonance imaging apparatus according to the first embodiment.

[0022] Figure 2 is a flowchart showing the generation of oblique images according to the first embodiment.

[0023] Figure 3A is a schematic diagram of a cross-sectional image of the knee obtained based on the pilot image three-dimensional volume data.

[0024] Figure 3BIt is a schematic diagram showing the identification of feature points from the cross-sectional image of the knee.

[0025] Figure 4 It is a schematic diagram showing the determination of the imaging direction of the oblique image based on the detected feature points.

[0026] Figure 5 It is a diagram showing an example of geometric parameters related to the oblique image of the knee.

[0027] Figure 6 It is a functional block diagram showing the magnetic resonance imaging apparatus of the second embodiment.

[0028] Figure 7 It is a flowchart showing the generation of the oblique image of the second embodiment.

[0029] Figure 8 It is a diagram showing an example of converting geometric parameters. Detailed implementation mode

[0030] (First embodiment)

[0031] Next, with reference to Figures 1 to 5 , the magnetic resonance imaging apparatus 10 of the first embodiment of the present invention will be described.

[0032] Figure 1 It is a functional block diagram showing the magnetic resonance imaging apparatus 10 of the first embodiment. As Figure 1 shown, the magnetic resonance imaging apparatus 10 includes a storage unit 100, an image acquisition unit 200, a feature point detection unit 300, a geometric parameter generation unit 400, an oblique image determination unit 500, and an oblique image generation unit 600.

[0033] The storage unit 100 in the present invention stores various data. Specifically, the storage unit 100 stores magnetic resonance data, three-dimensional volume data, image data, etc. for each subject (such as a human body). The storage unit 100 is implemented, for example, by semiconductor memory elements such as RAM (Random Access Memory), flash memory, hard disks, optical disks, etc.

[0034] The image acquisition unit 200, feature point detection unit 300, geometric parameter generation unit 400, oblique image determination unit 500, and oblique image generation unit 600 in the present invention are implemented by a processor, for example. The term "processor" may be a CPU (Central Processing Unit), GPU (Graphics Processing Unit), or an application specific integrated circuit (ASIC), a programmable logic device (e.g., a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA)), etc.

[0035] In addition, the above-described processing functions are stored in the storage unit 100 in the format of computer-executable programs. The processor realizes the processing functions corresponding to the respective programs by reading out the respective programs from the storage unit 100 and executing the read-out respective programs. Alternatively, it may be configured such that the programs are not held in the storage unit 100, but are directly loaded into the circuit of the processor. In this case, the processor realizes the functions by reading out and executing the programs loaded into the circuit.

[0036] Figure 1 In the magnetic resonance imaging apparatus 10, only the functional components related to the present invention are shown. Although not shown, the magnetic resonance imaging apparatus 10 further includes other mechanisms such as an examination table, an examination table control circuit, an input device, and a display.

[0037] The image acquisition unit 200 is a unit capable of acquiring three-dimensional volume data of an imaging region of a subject. More specifically, the image acquisition unit 200 generates high-frequency magnetic fields and receives magnetic resonance signals emitted from the subject due to the influence of the high-frequency magnetic fields, generates magnetic resonance data based on the detected magnetic resonance signals, and stores the magnetic resonance data in the storage unit 100. These functions of the image acquisition unit 200 are realized by, for example, a static magnetic field magnet, a static magnetic field power supply, gradient magnetic field coils, a gradient magnetic field power supply, a transmission coil, a transmission circuit, a reception coil, and a reception circuit (not shown).

[0038] Furthermore, the image acquisition unit 200 obtains three-dimensional volume data by arranging the magnetic resonance data of the imaging region of the subject in a three-dimensional space, and also stores the three-dimensional volume data of the imaging region of the subject in the storage unit 100. The function of the image acquisition unit 200 to generate three-dimensional volume data is realized by a processor, for example.

[0039] The feature point detection unit 300 can detect feature points in the three-dimensional volume data of the subject. The above-mentioned feature points refer to anatomical landmarks, also known as anatomical signs. There are a large number of feature points in the human body, and the positions and shapes of these feature points in the body are roughly determined according to physical characteristics such as age, adult / child, male / female, weight, and height. The feature point detection unit 300 identifies the above-mentioned feature points from the image based on the three-dimensional volume data through image processing such as pattern recognition. For example, the feature points of the heart include the base of the heart, the apex of the heart, the mitral valve, blood vessels, etc.

[0040] The geometric parameter generation unit 400 generates geometric parameters related to the oblique image according to the feature points detected from the three-dimensional volume data, such as geometric parameters including the imaging direction and imaging position of the oblique image.

[0041] The oblique image determination unit 500 determines the imaging protocol of the oblique image and the oblique types corresponding to each imaging protocol according to the examination instruction for the imaging part of the subject.

[0042] An imaging sequence library (or called "examination sequence repository") is also stored in the storage unit 100. The imaging sequence library includes the imaging sequences of each organ or part set in advance, and each organ or part can have multiple imaging sequences according to different imaging purposes. Each imaging sequence stipulates at least the imaging protocol of the oblique image and the oblique types corresponding to each imaging protocol. The oblique image determination unit 500 uses the examination part of the subject specified in the examination instruction to retrieve the imaging sequence library in the storage unit 100 and determines the imaging protocol corresponding to this examination part and the oblique types corresponding to each imaging protocol.

[0043] Table 1 below is an example of the imaging sequence library stored in the storage unit 100.

[0044]

Table 1

[0045]

[0046] As shown in Table 1, for the knee, imaging sequences such as "routine examination", "cruciate ligament", and "meniscus" are stored in the storage unit 100. In addition, in an imaging sequence such as the "cruciate ligament", the imaging protocol for the oblique image is specified to include three types: T1WI, T2WI, and PDWI. Among them, the types of oblique planes corresponding to T1WI include the oblique sagittal plane, the oblique coronal plane, and the oblique transverse plane; the types of oblique planes corresponding to T2WI include the oblique sagittal plane and the oblique coronal plane; and the types of oblique planes corresponding to PDWI include the oblique sagittal plane and the oblique coronal plane.

[0047] The oblique image generation unit 600 generates a variety of oblique images for the three-dimensional volume data acquired by the image acquisition unit 200, using the geometric parameters generated by the geometric parameter generation unit 400, in accordance with the imaging protocol and the type of oblique plane determined by the oblique image determination unit 500.

[0048] Next, taking the case where the imaging part of the subject is the cruciate ligament of the knee (right knee) as an example, the process of generating a variety of oblique images will be described.

[0049] Figure 2 It is a flowchart showing the generation of oblique images in the first embodiment.

[0050] First, in step S11, the operator of the magnetic resonance imaging device 10 receives an examination instruction from, for example, a doctor. The examination instruction records that the imaging part is the cruciate ligament of the knee of the subject.

[0051] Next, in step S12, the image acquisition unit 200 acquires three-dimensional volume data of a pilot image that can easily identify the anatomical structure of the knee of the subject for the cruciate ligament of the knee of the subject. For the knee, the imaging protocol that can easily identify the anatomical structure of the knee in image recognition is T1WI. Therefore, the imaging protocol at the time of image acquisition is set to T1WI, and thus three-dimensional volume data of the pilot image is acquired. Regarding the imaging protocol of the pilot image, it can be preset to an imaging protocol such as T1WI based on past experience, or imaging protocols corresponding to different imaging parts can be pre-stored in the storage unit 100, and the image acquisition unit 200 acquires the corresponding imaging protocol in step S12.

[0052] Next, in step S13, the feature point detection unit 300 detects feature points in the three-dimensional volume data of the pilot image. The feature point detection unit 300, for example, through pattern recognition processing, identifies the anatomical feature points of the knee from the image obtained based on the three-dimensional volume data of the pilot image.

[0053] Figure 3A and Figure 3B Shows an example of identifying the anatomical feature points of the knee based on the three-dimensional volume data of the pilot image.Figure 3A It is a schematic diagram of a cross-sectional image of the knee obtained based on the three-dimensional volume data of the leading image. Figure 3B It is a schematic diagram showing the identification of feature points from the cross-sectional image of the knee. As Figure 3B shown, through pattern recognition processing, the posterior vertex A1 of the medial femoral condyle and the posterior vertex A2 of the lateral femoral condyle are identified, and the lateral vertex A3 and the anterior vertex A4 in the outer contour of the lateral femoral condyle are also identified.

[0054] Then, in step S14, the geometric parameter generation unit 400 generates geometric parameters related to the oblique image based on the feature points detected from the three-dimensional volume data of the leading image, such as geometric parameters including the imaging direction and imaging position of the oblique image.

[0055] Figure 4 It is a schematic diagram showing the determination of the imaging direction of the oblique image based on the detected feature points.

[0056] In Figure 4 , the posterior vertex A1 of the medial femoral condyle and the posterior vertex A2 of the lateral femoral condyle can be used to determine the imaging direction of the oblique coronal plane, and the lateral vertex A3 and the anterior vertex A4 in the outer contour of the lateral femoral condyle can be used to determine the imaging direction of the oblique sagittal plane. More specifically, the connection line L1 between the posterior vertex A1 and the posterior vertex A2 is used to determine the imaging direction of the oblique coronal plane, and the connection line L2 between the right vertex A3 and the anterior vertex A4 is used to determine the imaging direction of the oblique sagittal plane.

[0057] In addition, although not shown, in the sagittal plane image of the knee obtained based on the three-dimensional volume data of the leading image, the imaging direction of the oblique cross-section of the knee can also be determined by identifying specific feature points.

[0058] In addition, in step S14, in addition to determining the imaging direction of the oblique image, the information on the imaging position of each oblique image can also be determined based on the identified feature points.

[0059] For example, in addition to identifying the posterior vertex A1 of the medial femoral condyle, the posterior vertex A2 of the lateral femoral condyle, the right vertex A3 and the anterior vertex A4 in the outer contour of the lateral femoral condyle, as Figure 4 shown, the anterior vertex A5 of the medial femoral condyle and the left vertex A6 of the medial femoral condyle can also be identified. Then, based on the above-mentioned feature points A1 to A6, the imaging position information such as the imaging field center point and imaging range of the knee is calculated.

[0060] The geometric parameter generation unit 400 generates geometric parameters related to the oblique image based on the determined imaging direction and imaging position of the oblique image, etc. The geometric parameters related to the oblique image are the geometric parameters used when generating each oblique image, for example, geometric parameters including the imaging direction and imaging position of the oblique image, etc.

[0061] Figure 5 It is a diagram showing an example of geometric parameters related to the oblique image of the knee.

[0062] In Figure 5 , the imaging direction of the oblique coronal plane calculated according to the orientation of the connection line L1 (shown as "SliceDirection (slice direction)" in the figure) represents the imaging direction parameter through the following coordinates representing the spatial vector.

[0063] [SliceDirection]

[0064] X = 0.30

[0065] Y = -0.94

[0066] Z = 0.06

[0067] In addition, the imaging position parameters such as the center point of the imaging field of view (shown as "FOVCenter" in the figure) and the imaging range (shown as "FOVSize") calculated according to multiple feature points are represented by the following three-dimensional spatial coordinates and spatial lengths.

[0068] [FOVCenter]

[0069] X = 0.21

[0070] Y = 0.21

[0071] Z = 10.46

[0072] [FOVSize]

[0073] FovC = 189.76

[0074] FovB = 239.86

[0075] FovA = 239.86

[0076] In addition, although Figure 5 omits the detailed content, the geometric parameters also include geometric parameters related to the oblique sagittal plane and the oblique transverse plane. Similarly, the geometric parameters related to the oblique sagittal plane can be calculated based on the orientation of the connection line L2.

[0077] In addition, the geometric parameters related to the oblique transverse plane can be based on Figure 4It is determined by the feature points A1 to A6 and / or other feature points in [it], or it can also be calculated based on other images outside the cross-sectional image (such as the feature points in the sagittal image). In addition, the geometric parameters corresponding to the oblique cross-section of the knee can be preset based on empirical values.

[0078] On the other hand, after the above step S11, it proceeds to step S15. In step S15, the oblique image determination unit 500 obtains the imaging sequence corresponding to the cruciate ligament of the knee from the imaging sequence library stored in the storage unit 100 according to the cruciate ligament of the knee described in the inspection instruction, so as to determine the imaging protocol of the oblique image and the types of obliques corresponding to each imaging protocol.

[0079] As shown in Table 1 above, there are a total of 7 types of oblique images corresponding to the cruciate ligament of the knee, including oblique sagittal T1WI image, oblique coronal T1WI image, oblique cross-sectional T1WI image, oblique sagittal T2WI image, oblique coronal T2WI image, oblique sagittal PDWI image, and oblique coronal PDWI image.

[0080] Next, in step S16, the image acquisition unit 200 acquires the official three-dimensional volume data of the cruciate ligament of the knee. More specifically, the image acquisition unit 200 acquires the official three-dimensional volume data corresponding to each imaging protocol according to each imaging protocol determined in step S15. That is, for each imaging protocol corresponding to the cruciate ligament of the knee, the official three-dimensional volume data corresponding to T1WI, the official three-dimensional volume data corresponding to T2WI, and the official three-dimensional volume data corresponding to PDWI are acquired.

[0081] Next, in step S17, the oblique image generation unit 600 generates various types of oblique images determined in step S15 for the official three-dimensional volume data acquired in step S16, using the geometric parameters generated in step S14.

[0082] More specifically, the oblique image generation unit 600 generates three types of oblique images corresponding to T1WI (i.e., oblique sagittal T1WI image, oblique coronal T1WI image, and oblique transverse T1WI image) for the official three-dimensional volume data corresponding to T1WI, using the geometric parameters including the imaging direction parameters generated in step S14. Then, the oblique image generation unit 600 generates two types of oblique images corresponding to T2WI (i.e., oblique sagittal T2WI image and oblique coronal T2WI image) for the official three-dimensional volume data corresponding to T2WI, using the same geometric parameters. Then, the oblique image generation unit 600 generates two types of oblique images corresponding to PDWI (i.e., oblique sagittal PDWI image and oblique coronal PDWI image) for the official three-dimensional volume data corresponding to PDWI, using the same geometric parameters.

[0083] In addition, when generating oblique images, in addition to using the above geometric parameters, some image reconstruction parameters including the number of slices, slice thickness, etc. are usually also required, and detailed descriptions are omitted here.

[0084] According to the magnetic resonance imaging apparatus 10 of the first embodiment, since the same geometric parameters are used to generate oblique images of the imaging part for three different imaging protocols of T1WI, T2WI, and PDWI, a variety of oblique images with consistent imaging directions can be automatically generated.

[0085] For the imaging part of the cruciate ligament of the knee in this embodiment, by using the geometric parameters for generating oblique images based on a pilot image that can easily identify the anatomical structure of the knee, the imaging directions of the oblique sagittal T1WI image, oblique sagittal T2WI image, and oblique sagittal PDWI image can be made consistent, and the imaging directions of the oblique coronal T1WI image, oblique coronal T2WI image, and oblique coronal PDWI image can be made consistent. Even for an imaging protocol that is not easy to detect feature points (such as T2WI), oblique images with imaging directions consistent with those of other imaging protocols can be generated.

[0086] In addition, compared with a magnetic resonance imaging apparatus that directly obtains two-dimensional images as oblique images, the magnetic resonance imaging apparatus 10 of this embodiment only needs to obtain three-dimensional volume data once for each imaging protocol, and can greatly shorten the time required for imaging all oblique images.

[0087] (Second Embodiment)

[0088] Next, with reference to Figures 6 to 7 , the magnetic resonance imaging apparatus 20 of the second embodiment of the present invention will be described.

[0089] Figure 6 is a functional block diagram of the magnetic resonance imaging apparatus 20 according to the second embodiment. As Figure 6 shown, in addition to including a storage unit 100, an image acquisition unit 200, a feature point detection unit 300, a geometric parameter generation unit 400, an oblique image determination unit 500, and an oblique image generation unit 600, the magnetic resonance imaging apparatus 20 further includes a geometric parameter conversion unit 700. Hereinafter, the same description as that of the first embodiment will be omitted, and only the differences will be described.

[0090] Figure 7 is a flowchart for generating an oblique image according to the second embodiment.

[0091] In Figure 7 , step S18 is added before generating the oblique image of the imaging region (step S17). In step S18, the geometric parameter conversion unit 700 registers the acquired pilot image three-dimensional volume data with the formal three-dimensional volume data, and converts the geometric parameters for oblique image imaging into geometric parameters corresponding to the formal three-dimensional volume data based on the registration result.

[0092] More specifically, by performing image registration of the pilot image three-dimensional volume data with a plurality of formal three-dimensional volume data respectively, a transformation matrix corresponding to the pilot image three-dimensional volume data and each formal three-dimensional volume data is generated, and then using each transformation matrix, the geometric parameters generated in step S14 are respectively converted into geometric parameters corresponding to each formal three-dimensional volume data.

[0093] Figure 8 is a diagram showing an example of converting geometric parameters. As Figure 8 shown, based on the registration between the pilot image three-dimensional volume data and the formal three-dimensional volume data corresponding to T1WI, the formal three-dimensional volume data corresponding to T2WI, and the formal three-dimensional volume data corresponding to PDWI obtained in step S16, the geometric parameters generated in step S14 are respectively converted into three sets of geometric parameters corresponding to the above three formal three-dimensional volume data. That is, it is converted into geometric parameters corresponding to T1WI, geometric parameters corresponding to T2WI, and geometric parameters corresponding to PDWI.

[0094] Then, in step S17 of the second embodiment, the oblique image generation unit 600 uses the three sets of converted geometric parameters and the three formal three-dimensional volume data corresponding to the three sets of geometric parameters respectively to generate a variety of oblique images corresponding to the oblique type and imaging protocol determined in step S15.

[0095] More specifically, for the official three-dimensional volume data corresponding to T1WI, the oblique image generation unit 600 generates three types of oblique images corresponding to T1WI (i.e., oblique sagittal plane T1WI image, oblique coronal plane T1WI image, and oblique transverse plane T1WI image) using the geometric parameters corresponding to T1WI generated in step S18. Then, for the official three-dimensional volume data corresponding to T2WI, the oblique image generation unit 600 generates two types of oblique images corresponding to T2WI (i.e., oblique sagittal plane T2WI image and oblique coronal plane T2WI image) using the geometric parameters corresponding to T2WI. Then, for the official three-dimensional volume data corresponding to PDWI, the oblique image generation unit 600 generates two types of oblique images corresponding to PDWI (i.e., oblique sagittal plane PDWI image and oblique coronal plane PDWI image) using the geometric parameters corresponding to PDWI.

[0096] Since the acquisition times of the pilot image three-dimensional volume data, the official three-dimensional volume data corresponding to T1WI, the official three-dimensional volume data corresponding to T2WI, and the official three-dimensional volume data corresponding to PDWI are different, there is a situation where the coordinates of the same anatomical structure are different in different three-dimensional volume data.

[0097] According to the magnetic resonance imaging apparatus 20 of the second embodiment, through the conversion process performed by the geometric parameter conversion unit 700, multiple sets of geometric parameters that are more matched with each official three-dimensional volume data are generated based on the same geometric parameters, and then various types of oblique images of the imaging region are generated. As a result, the imaging direction error caused by the differences between the three-dimensional volume data is further eliminated, and various types of oblique images with more consistent imaging directions can be automatically generated. Especially when the imaging region is the chest, heart, abdomen, etc., since the imaging region changes with breathing or pulsation, the consistency of the imaging directions between various types of oblique images can be significantly improved by performing the geometric parameter conversion process.

[0098] (Modification example)

[0099] Several embodiments of the present invention have been described, but the above embodiments are merely illustrative and are not intended to limit the scope of the invention. These embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and its equivalents.

[0100] For example, in step S14 of the first embodiment, information is described that the imaging positions of the respective oblique images can be determined based on the identified feature points. In fact, the imaging positions of the oblique images can also be preset based on empirical values for different imaging parts and imaging purposes. In addition, it is also possible to consider determining the center point of the imaging field of view based on the identified feature points, and then using a range preset based on empirical values for the imaging range.

Claims

1. A magnetic resonance imaging apparatus, characterized in that, it has: an image acquisition unit that acquires three-dimensional volume data of a pilot image that can easily identify anatomical structures for an imaging region of a subject; a geometric parameter generation unit that generates geometric parameters including an imaging direction of an oblique image based on feature points detected from the three-dimensional volume data of the pilot image; an oblique image determination unit that determines an imaging protocol for the oblique image and an oblique type corresponding to each imaging protocol according to an examination instruction for the imaging region; and an oblique image generation unit that generates multiple types of oblique images corresponding to the determined imaging protocol and the oblique type for one or more formal three-dimensional volume data acquired by the image acquisition unit, using the geometric parameters, the magnetic resonance imaging apparatus further includes a geometric parameter conversion unit, before generating the oblique image, the geometric parameter conversion unit performs image registration on the acquired three-dimensional volume data of the pilot image and one or more formal three-dimensional volume data respectively, and based on the result of the image registration, converts the geometric parameters into one or more sets of geometric parameters corresponding to the one or more formal three-dimensional volume data respectively, the oblique image generation unit generates the multiple types of oblique images using the converted geometric parameters and the formal three-dimensional volume data.

2. The magnetic resonance imaging apparatus according to claim 1, characterized in that, the geometric parameters include one or more imaging direction parameters, and the one or more imaging direction parameters respectively correspond to one or more of the oblique types, for each formal three-dimensional volume data respectively corresponding to each imaging protocol, the oblique image generation unit generates oblique images of one or more of the oblique types corresponding to the imaging protocol using the geometric parameters including the imaging direction parameters.

3. The magnetic resonance imaging apparatus according to claim 2, characterized in that, the geometric parameters further include one or more imaging position parameters, the one or more imaging position parameters respectively correspond to the one or more imaging direction parameters, each imaging position parameter includes information indicating the center point of the imaging field of view and the imaging range.

4. The magnetic resonance imaging apparatus according to claim 1, characterized in that, the three-dimensional volume data of the pilot image is three-dimensional volume data acquired using an imaging protocol that can easily identify the anatomical structure of the imaging region.

5. The magnetic resonance imaging apparatus according to claim 1, characterized in that, the oblique types include at least one of an oblique coronal plane, an oblique sagittal plane, and an oblique cross-sectional plane, the imaging protocols include at least one of a longitudinal relaxation weighted image, a transverse relaxation weighted image, a proton density image, a fluid attenuated inversion recovery image, a diffusion weighted image, and a perfusion weighted image.

6. A magnetic resonance imaging method, characterized in that, it includes: a pilot image acquisition step of acquiring three-dimensional volume data of a pilot image that can easily identify anatomical structures for an imaging region of a subject; A geometric parameter generation step of generating geometric parameters including the imaging direction of the oblique image based on the feature points detected from the pilot image three-dimensional volume data; An oblique image determination step of determining the imaging protocol of the oblique image and the corresponding oblique types for each imaging protocol according to the examination instruction for the imaging part; An official image acquisition step of acquiring one or more official three-dimensional volume data for the imaging part; An oblique image generation step of generating multiple types of oblique images corresponding to the determined imaging protocol and the oblique types using the geometric parameters for the one or more official three-dimensional volume data obtained; Before the oblique image generation step, there is also a geometric parameter conversion step; In the geometric parameter conversion step, the acquired pilot image three-dimensional volume data is respectively registered with one or more of the official three-dimensional volume data, and based on the result of the image registration, the geometric parameters are converted into one or more sets of geometric parameters corresponding to the official three-dimensional volume data respectively; In the oblique image generation step, multiple types of oblique images corresponding to the oblique types and imaging protocol are generated using the converted geometric parameters and the official three-dimensional volume data.

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