JP6580823B2 - Medical image processing apparatus and MRI apparatus - Google Patents

Description

  Embodiments as one aspect of the present invention relate to a medical image processing apparatus and an MRI apparatus.

  In an MRI (Magnetic Resonance Imaging) apparatus, there is an imaging method called dynamic imaging that performs imaging in time series in order to inject a contrast agent or the like into the body and observe the pharmacokinetics of the contrast agent over time. By using such dynamic imaging, for example, a location where the blood flow volume is increased as compared with a normal tissue such as a tumor such as cancer can be identified. In addition, by observing blood flow dynamics such as the speed at which blood flows into the tissue (wash in) and the speed at which blood flows into the tissue (wash out), the tumor identification and tumor malignancy can be determined. Can be determined. In order to observe such blood flow dynamics, a time intensity curve (TIC: Time Intensity Curve) in which signals for each pixel imaged at each time phase are arranged and graphed at each time phase is generated, and based on the TIC. The degree of malignancy of the tumor can be determined.

  For example, a diagnostic guideline (BI-RADS-MRI: Breast Imaging. Reporting and Data System MRI) using an MRI apparatus in breast cancer advocates the implementation of Kinetic Curve Assessment based on the above-mentioned TIC in making a diagnosis. . The evaluation method in Kinetic Curve Assessment is a method in which TIC is divided into an early phase and a late phase, and the rising time of the graph is an early phase, and the malignancy of the tumor is determined based on the change in the graph between the early phase and the late phase. . For example, if the rise is earlier than the reference in the early phase, or if the fall of the graph is early in the late phase, it is evaluated that the possibility of malignancy is high.

  Based on these guidelines, the grade of malignancy of the tumor is determined, and whether or not to perform biological tissue diagnosis (biopsy test) or the like is specified, and used to create a treatment plan. .

  In recent years, a technique called non-contrast-enhanced MRI that does not use a contrast agent has been developed, and it has become possible to perform a less invasive examination. As the non-contrast MRI method, a TOF (Time of Flight) method using the inflow effect of blood, a PC (phase contrast) method using a phase shift when blood moves in a gradient magnetic field, and the like have been developed. Even in such a non-contrast technique, a technique for performing dynamic imaging in which time-series imaging is performed as in the case of using a contrast agent and determining the malignancy of a tumor from blood flow dynamics is provided (for example, Patent Document 1).

JP 2014-64703 A

  However, since dynamic imaging continuously images a subject, positional displacement may occur between images acquired in each time phase due to body movement (breathing or body movement). When the position shift occurs, the corresponding pixel is shifted between the respective time phases. Therefore, it is possible that the pixel in which the tumor exists exists in one time phase but does not exist in another time phase. In such a case, a correct TIC cannot be created, and an accurate Kinetic Curve Assessment cannot be performed. As described above, the diagnostic guidelines describe a method for evaluating the malignancy of a tumor based on TIC, and image analysis based on accurate TIC is required.

  Therefore, there is a demand for a medical image processing apparatus that can perform accurate image analysis.

  The medical image processing apparatus according to the present embodiment sets a plurality of regions of interest in one of the medical images captured in a plurality of time phases, and the plurality of set regions of interest are imaged in other time phases. A region-of-interest setting unit to be set for each medical image, a position alignment processing unit for performing alignment for each region of interest corresponding between a plurality of time phases, and an analysis for performing image analysis for each region of interest corresponding to the plurality of time phases And a display control unit that superimposes the result of the image analysis on at least one of the medical images captured in the plurality of time phases and displays the result on the display unit.

1 is a conceptual configuration diagram illustrating an example of an MRI apparatus according to an embodiment. FIG. 3 is a functional block diagram showing an example functional configuration of the medical image processing apparatus according to the embodiment. 6 is a flowchart showing an example of the operation of the medical image processing apparatus according to the embodiment. The figure explaining the medical image acquired by dynamic imaging. The figure explaining the position shift of the medical image acquired by the dynamic imaging. The figure explaining the setting method of the region of interest in the medical image processing apparatus which concerns on embodiment. FIG. 6 is a diagram for explaining a position alignment method in the medical image processing apparatus according to the embodiment. FIG. 3 is a diagram for explaining a TIC generated by the medical image processing apparatus according to the embodiment. The figure explaining the example of the blood flow dynamics map produced | generated with the medical image processing apparatus which concerns on embodiment. FIG. 6 is a diagram for explaining a display example of a superimposed image displayed by the medical image processing apparatus according to the embodiment. The figure explaining the other example of the blood flow dynamics map produced | generated with the medical image processing apparatus which concerns on embodiment. FIG. 6 is a view for explaining another display example of a superimposed image displayed by the medical image processing apparatus according to the embodiment.

  Hereinafter, an embodiment of a medical image processing apparatus will be described with reference to the accompanying drawings.

  FIG. 1 is a conceptual configuration diagram illustrating an example of an MRI apparatus according to an embodiment. As shown in FIG. 1, the MRI apparatus 1 includes an imaging unit 100 and a medical image processing apparatus 200. The imaging unit 100 includes a static magnetic field magnet 110, a gradient magnetic field coil 120, a transmission coil 130, a reception coil 140, a bed apparatus 151, a top panel 152, a transmission unit 13, a reception unit 14, a gradient magnetic field power supply 11, a bed control unit 12, and a sequence. A control unit 15 is provided. The imaging unit 100 according to the present embodiment can perform dynamic imaging that captures medical images in a plurality of time phases.

  The static magnetic field magnet 110 is formed in a hollow cylindrical shape, and generates a uniform static magnetic field in an internal space by a current supplied from a static magnetic field power source (not shown). For example, the static magnetic field magnet 110 is composed of a permanent magnet, a superconducting magnet, or the like. The gradient coil 120 is formed in a hollow cylindrical shape and generates a gradient magnetic field in the internal space. Specifically, the gradient magnetic field coil 120 is disposed inside the static magnetic field magnet 110 and generates a gradient magnetic field upon receiving a current supplied from a gradient magnetic field power supply 11 described later.

  The transmission coil 130 is arranged inside the gradient magnetic field coil 120 and receives an RF (radio frequency) signal supplied from the transmission unit 13 to generate an RF magnetic field. The transmission coil 130 is also used as a reception coil and is also called a whole body RF coil.

  The receiving coil 140 is disposed inside the transmitting coil 130 and receives an MR signal radiated from the subject P in response to the RF signal. FIG. 1 illustrates a receiving coil 140 for breast imaging. When imaging is performed using the receiving coil 140 for breast imaging, the subject P is placed on the bed in a prone position, and imaging is performed by placing the breast in a space opened in the receiving coil 140 for breast imaging.

  The bed apparatus 151 includes a top plate 152 on which the subject P is placed, and the top plate 152 on which the subject P is placed is inserted into the cavity (imaging port) of the transmission coil 130. Usually, the bed apparatus 151 is installed so that the longitudinal direction is parallel to the central axis of the static magnetic field magnet 110.

  The gradient magnetic field power supply 11 supplies a current to the gradient magnetic field coil 120 based on the pulse sequence execution data sent from the sequence control unit 15. Here, the gradient magnetic field generated by the gradient coil 120 includes a readout gradient magnetic field Gr, a phase encoding gradient magnetic field Ge, and a slice selection gradient magnetic field Gs. The readout gradient magnetic field Gr is used to change the frequency of the MR signal in accordance with the spatial position. The phase encoding gradient magnetic field Ge is used to change the phase of the MR signal in accordance with the spatial position. The slice selection gradient magnetic field Gs is used to arbitrarily determine an imaging section. For example, when acquiring a slice of an axial cross section, the X, Y, and Z axes shown in FIG. 1 correspond to the readout gradient magnetic field Gr, the phase encoding gradient magnetic field Ge, and the slice selection gradient magnetic field Gs, respectively. Let

  The couch control unit 12 is a device that controls the couch device 151, and drives the couch device 151 under the control of the sequence control unit to move the couchtop 152 in the longitudinal direction and the vertical direction.

  The transmission unit 13 transmits an RF signal corresponding to the Larmor frequency to the transmission coil 130 based on the pulse sequence execution data sent from the sequence control unit 15.

  The reception unit 14 generates MR signal data from the MR signal output from the reception coil 140 based on the pulse sequence execution data sent from the sequence control unit 15. Further, when generating the MR signal data, the receiving unit 14 transmits the MR signal data to the medical image processing apparatus 200 via the sequence control unit 15.

  The sequence control unit 15 is connected to the gradient magnetic field power supply 11, the bed control unit 12, the transmission unit 13, the reception unit 14, and the medical image processing apparatus 200. The sequence control unit 15 includes a processor (not shown) such as a CPU (central processing unit) and a memory, and is necessary for driving the gradient magnetic field power supply device 11, the bed control unit 12, the transmission unit 13, and the reception unit 14. Such control information, for example, sequence information describing operation control information such as the intensity, application time, and application timing of the pulse current to be applied to the gradient magnetic field power supply device 11 is stored. In the MRI apparatus 1 according to the present embodiment, sequence information for performing dynamic imaging is stored. The sequence control unit 15 drives the gradient magnetic field power supply device 11, the transmission unit 13, and the reception unit 14 in accordance with the stored predetermined sequence information, so that the X-axis gradient magnetic field Gx, the Y-axis gradient magnetic field Gy, and the Z-axis are placed in the gantry. A gradient magnetic field Gz and an RF signal are generated. Furthermore, by driving the bed control unit 12 according to the stored predetermined sequence information, the tabletop 152 is moved forward and backward in the Z direction with respect to the gantry.

  The medical image processing apparatus 200 performs overall control of the MRI apparatus 1, acquisition of MR signal data, image reconstruction, and the like. The medical image processing apparatus 200 includes an interface unit 210, an input unit 220, a display unit 230, an image reconstruction unit 240, a storage unit 250, and a control unit 260.

  The interface unit 210 is connected to the gradient magnetic field power supply device 11, the bed control unit 12, the transmission unit 13, and the reception unit 14 of the imaging unit 100 via the sequence control unit 15, and these connected units and medical images. Controls input / output of signals exchanged with the processing apparatus 200.

  The input unit 220 receives various operations and information input from an operator, has a pointing device such as a mouse and a trackball, a keyboard, and the like, and cooperates with the display unit 230 to receive various operations. User Interface) is provided to the operator of the MRI apparatus 1.

  The display unit 230 displays various information such as image data under the control of the control unit 260 described later. A display device such as a liquid crystal display can be used as the display unit 230.

  The image reconstruction unit 240 reconstructs an MRI image by performing reconstruction processing such as Fourier transform on the MR signal data stored in the storage unit 250 and stores the reconstructed MRI image in the storage unit 250. To do.

  The storage unit 250 stores MR signal data received by the interface unit 210, MRI images stored by the image reconstruction unit 240, other data used in the MRI apparatus 1, programs, and the like. The storage unit 250 includes a storage medium such as a RAM and a ROM, and includes a storage medium readable by the control unit 260 such as a magnetic or optical storage medium or a semiconductor memory. Some or all of the programs and data in these storage media may be downloaded via an electronic network.

  The control unit 260 comprehensively controls the MRI apparatus 1 by controlling each unit described above. For example, by executing a program stored in the storage unit 250, an image is reconstructed from MR signals, a medical image according to this embodiment is aligned, and a blood flow dynamic map is generated.

  FIG. 2 is a functional block diagram illustrating a functional configuration example of the medical image processing apparatus 200 according to the embodiment. As illustrated in FIG. 2, the medical image processing apparatus 200 includes an image storage unit 251, a region of interest setting unit 261, a registration processing unit 263, an analysis unit 265, a display control unit 267, an input unit 220, and a display unit 230. The Of these, the region-of-interest setting unit 261, the alignment processing unit 263, the analysis unit 265, and the display control unit 267 are functions realized by the program stored in the storage unit 250 being executed by the control unit 260.

  The medical image processing apparatus 200 may acquire medical images by receiving MR signal data from the MRI apparatus 1 as shown in FIG. 1 and reconstructing the images, or medical images captured by the MRI apparatus 1. A medical image may be acquired from a medical image central management system (PACS: Picture Archiving and Communication Systems) in which images are accumulated. That is, the medical image processing apparatus 200 may be mounted on the console of the MRI apparatus 1, may be mounted on a workstation, or may be mounted on a cloud computer.

  The image storage unit 251 stores medical images captured in a plurality of time phases. In dynamic imaging in which a change in contrast agent is observed in time series using a contrast agent or the like, a medical image is acquired at each of a plurality of time phases.

  The region-of-interest setting unit 261 sets a plurality of regions of interest in one of the medical images captured in a plurality of time phases, and sets the plurality of regions of interest set as medical images captured in other time phases. To do. The region of interest can be set to a local region in which a lesion such as a tumor is estimated to exist. For example, a tumor such as cancer has blood vessels developed, and a contrast medium or the like is likely to be localized, and the signal intensity of a region where the tumor is present becomes high. Therefore, a region of interest can be set in such a high signal region. A method of setting a region of interest in the region of interest setting unit 261 will be described later.

  The alignment processing unit 263 performs alignment for each region of interest corresponding between a plurality of time phases. An alignment method in the alignment processing unit 263 will be described later.

  The analysis unit 265 performs image analysis for each region of interest corresponding between a plurality of time phases. In the analysis unit 265, a TIC is generated, and a hemodynamic map is generated based on the TIC. The hemodynamic map is a map that maps the results of analyzing the blood flow based on the TIC, and maps the results of determining the malignancy of the tumor from the TIC based on the Kinetic Curve Assessment, A maximum intensity time map in which the time phase indicating the maximum intensity is mapped, a maximum intensity value map in which the maximum intensity value is mapped, and the like are included. A method of generating a blood flow dynamic map in the analysis unit 265 will be described later.

  The display control unit 267 superimposes the result of image analysis on at least one of the medical images picked up at a plurality of time phases and displays the result on the display unit 230. For example, the display control unit 267 generates a superimposed image in which the blood flow dynamic map generated by the analysis unit 265 is superimposed on a difference image at a certain time phase, and displays the superimposed image on the display unit 230. The superimposed image generated by the display control unit 267 and displayed on the display unit 230 will be described later.

  Hereinafter, the operation of the medical image processing apparatus 200 according to the embodiment will be described based on a flowchart by taking as an example a case where dynamic imaging of a breast is performed. Hereinafter, an example of contrast-enhanced MRI of a breast (including a non-contrast imaging method) will be described. However, the medical image processing apparatus 200 according to the present embodiment is not limited to the breast, and blood flow such as the head, chest, and abdomen. It is applicable when observing a tumor or the like by image processing based on dynamics.

  FIG. 3 is a flowchart illustrating an example of the operation of the medical image processing apparatus according to the embodiment.

  In ST101, dynamic imaging is performed in the imaging unit 10 of the MRI apparatus 1. In dynamic imaging, a T1-weighted image is normally captured.

  In ST103, a plurality of medical images captured in a plurality of time phases are input to the image storage unit 251. Each of the medical images captured at each time phase in dynamic imaging may be two-dimensional image data or three-dimensional volume data.

  In ST105, a medical image captured at each time phase is displayed on the display unit 230. The displayed medical image may be, for example, a difference image between a medical image before contrasting and a medical image captured at each time phase after contrasting, or a T1-weighted image at each time phase after contrasting. May be.

  FIG. 4 is a diagram for explaining a medical image acquired by dynamic imaging. FIG. 4 illustrates medical images acquired from the left in time phase 1, time phase 2... Time phase N. The high-signal areas A and B are indicated by black circles in the medical images captured at each time phase. High signal areas A and B are areas corresponding to anatomical sites in each time phase. That is, it shows a lesion existing in the same anatomical structure or structure. In dynamic imaging, for example, imaging is performed at an imaging interval such as 1 minute. Therefore, not only the influence of respiration of the subject P but also the positional deviation of images acquired in each time phase occurs due to body movement. Therefore, as shown in FIG. 4, the high signal areas A and B of each time phase are different from each other even though they are the same anatomical part. In FIG. 4, the high signal area is indicated by a circle. However, the shape of the high signal area is not limited to a circle, but may be a rod shape, a polygonal shape, or a cluster of small high signal areas. There is. Since these high-signal areas have a three-dimensional shape in the body, when a position shift occurs due to body movement or the like, the shape of the high-signal area displayed on the image corresponds to the anatomical position. Even a thing may be displayed in various shapes for each time phase.

  FIG. 5 is a diagram for explaining a positional shift of a medical image acquired by dynamic imaging. FIG. 5 illustrates a case where the medical images of time phase 1 and time phase N shown in FIG. 4 are superimposed. The image of time phase 1 is indicated by a solid line, and the image of time phase N is indicated by a broken line. Further, the high signal areas A and B observed at time phase 1 are indicated by black circles, and the high signal areas A and B observed at time phase N are indicated by shaded circles. The high signal areas A and B of time phase 1 and time phase N are high signal areas observed in areas corresponding to anatomical positions.

  As shown in FIG. 5, the time phase 1 and the time phase N are displaced due to body movements, and not only the contour of the breast but also the positions of the high signal regions A and B are greatly displaced.

  When such a displacement occurs, a correct TIC cannot be obtained. This is because the TIC is obtained by graphing the signal value of the corresponding pixel in each time phase. Therefore, even if Kinetic Curve Assessment is performed to evaluate the malignancy of a tumor based on a TIC created in a state where a positional deviation has occurred, a correct evaluation cannot be performed.

  Even when rigid body alignment (linear alignment) is performed in which the medical image of time phase 1 and the medical image of time phase N are aligned by rotating and translating the images, both high-signal regions It cannot be aligned. In addition, even when non-rigid registration (non-linear registration) is performed in which alignment is performed by deforming an image, for example, a method is used that performs alignment based on the correspondence between feature points of two images. In this case, if the correspondence between the feature points cannot be correctly derived, correct alignment cannot be performed.

  Therefore, in the medical image processing apparatus 200 according to the present embodiment, a blood flow dynamic map based on a correct TIC is obtained by focusing on a region of interest that is a predetermined local region surrounding a high signal region and performing alignment for each region of interest. The technique which can produce | generate is provided.

  Hereinafter, a method of generating a blood flow dynamic map by performing alignment for each region of interest will be described with reference to the flowchart of FIG.

  First, a method for setting a region of interest will be described.

  In ST107, the region of interest setting unit 261 sets a region of interest for a medical image of a specific time phase. The region of interest can be set to a region surrounding the high signal region within a predetermined range. The region of interest may be input by the user or the like via the input unit 220 provided with an input device such as a mouse, or may be set by automatically determining the high signal region by image processing.

  In ST109, the region-of-interest setting unit 261 sets a region of interest in the high-signal region of another time phase corresponding to the region of interest set in the high-signal region of a certain phase. The setting of the region of interest for another time phase may be manual or automatic. For example, after a pixel range corresponding to a region of interest set in a certain time phase is set as a region of interest in another time phase, a high signal region corresponding to the user or the like via the input unit 220 is included in the region of interest. It may be set by editing as follows. In addition, based on image similarity and feature points other than the high-signal area, the corresponding high-signal area is searched according to the predetermined area (for example, the maximum range in which displacement occurs), and the area of interest is automatically set. It may be possible. At this time, for example, the position of the region of interest is set so that the center of the high signal region in each time phase and the center of the region of interest coincide, or the center of the high signal region and the center of the region of interest in each time phase It is preferable that the position of the region of interest is set so that the relative positional relationship between and is the same.

  FIG. 6 is a diagram for explaining a region of interest setting method in the medical image processing apparatus 200 according to the embodiment. FIG. 6 shows an example of a dynamic image captured in time phase 1, time phase 2... Time phase N as in FIG. In FIG. 6, a rectangular region of interest of a predetermined region centering on the high signal regions A and B observed in each time phase is shown. The high signal areas A and B shown in each time phase each have the same anatomical position.

  In FIG. 6, a rectangular frame is shown in the region of interest AN as a region of interest corresponding to the high signal region A of time phase N, and a rectangular frame is shown in the region of interest BN as a region of interest corresponding to the high signal region B of time phase N. (Where N is an integer of 1 or more).

  In this way, the region of interest is set as a region having a predetermined area centered on the high signal region corresponding to the anatomical position at each time phase, for example. Therefore, when the subject P moves between time phases, the position (for example, pixel position) of the region of interest displayed on the display unit 230 also differs.

  In the example of FIG. 6, the region of interest is indicated by a rectangular frame, but it may be a circle or other polygons. Further, the size and shape of the region of interest may be freely set by the user or the like. For example, the size of the region of interest is defined as 3 pixels or more according to the above-mentioned breast cancer diagnostic guidelines (BI-RADS-MRI).

  In the medical image processing apparatus 200 according to the present embodiment, the regions of interest corresponding to the anatomical positions set in each time phase need to be the same size and the same shape. Regions of interest that do not correspond to anatomical positions may have different sizes and shapes. Specifically, in the example of FIG. 6, regions of interest A1, A2... AN (hereinafter referred to as region of interest A set), regions of interest B1, B2... BN (hereinafter referred to as region of interest B set). The regions of interest included in each region of interest set must be the same size and shape, but the regions of the region of interest A and the region of interest B set have different sizes and shapes. It may be.

  After the region of interest is set as described above, a blood flow dynamic map based on the TIC focusing on the region of interest is generated.

  Hereinafter, returning to the flowchart of FIG. 3, generation of the TIC and the hemodynamic map will be described.

  In ST111, the alignment processing unit 263 performs alignment for each of a plurality of region-of-interest sets. The alignment processing unit 263 performs alignment so that pixels of each region of interest included in the region of interest set correspond to each other. By this alignment processing, the pixels of each region of interest included in the region of interest set are aligned for each time phase.

  In ST113, analysis unit 265 calculates a TIC for each region of interest set.

  In ST115, the analysis unit 265 generates a blood flow dynamic map based on the TIC.

  In ST117, the display generation unit 267 generates a superimposed image in which the blood flow dynamic map and the medical image are superimposed, and displays them on the display unit 230.

  FIG. 7 is a diagram for explaining a positioning method in the medical image processing apparatus 200 according to the embodiment. FIG. 7 illustrates a region of interest A set including regions of interest A1, A2,... AN corresponding to the high signal region A of each time phase shown in FIG. FIG. 7 shows an example in which each region of interest is composed of 9 pixels of 3 × 3. The number shown in each region of interest indicates the pixel number.

  As described above, the size and shape of the regions of interest included in the same region of interest set are the same. Therefore, for example, pixels of other regions of interest can be easily associated with the region of interest A1 of time phase 1 as a reference. Specifically, the pixel 1 at the upper left of the region of interest A1 in time phase 1 can be associated with the pixel 1 at the upper left of the region of interest A2 in time phase 2. Similarly, the upper left pixel 1 of the region of interest A1 can be associated with the upper left pixel 1 of the region of interest N in the time phase N. In this way, pixels can be associated with all regions of interest, and the corresponding pixels in each time phase can be aligned in time series. The TIC is a graph in which the signal value of each pixel is plotted for each time phase. The alignment processing unit 263 associates the pixels of each region of interest in the region of interest set, so that a correct graph can be calculated.

  FIG. 8 is a diagram illustrating a TIC generated by the medical image processing apparatus 200 according to the embodiment. FIG. 8 shows an example of the TIC of the pixel 1, the pixel 5, and the pixel 9 in the region of interest A set in FIG. The example of FIG. 8 shows an example in which Kinetic Curve Assessment is performed with time phase 1 to time phase 3 as an early phase and time phase 4 and later as a late phase.

  The middle part of FIG. 8 shows the TIC of the pixel 5. It is observed that the TIC of pixel 5 has a quick rise in the early phase, and the signal strength is rapidly reduced in the late phase, indicating that the inflow into the tissue (Wash In) and the outflow from the tissue (Wash Out) are fast. ing. When such TIC is shown, it is estimated that the tumor is a tumor such as breast cancer, and is evaluated as “strongly doubting malignancy”.

  It should be noted that the rising speed or slowness in the TIC graph may be determined based on whether or not a predetermined threshold value is exceeded. For example, the determination may be made based on an index such as a high α% signal value or a large inclination with respect to the threshold.

  The lower part of FIG. 8 shows the TIC of the pixel 9. The TIC rise of the pixel 9 is slower than that of the pixel 5 in the early phase, and continues to rise even after reaching the late phase. Such TIC is often observed in benign tumors and is evaluated as “benign”.

  The upper part of FIG. 8 shows the TIC of the pixel 1. The TIC of the pixel 1 rises quickly in the early phase, maintains the signal intensity in the late phase, and is in a flat region. That is, the transition of the signal intensity in the late phase shows between the pixel 5 determined as “strongly doubting malignancy” and the pixel 9 determined as “benign”. If the TIC shows such a shape, it may be malignant, so it is evaluated as “suspecting malignancy”.

  The analysis unit 265 determines the benign / malignant as described above based on the shape of the TIC, and generates a blood flow dynamic map.

  FIG. 9 is a diagram illustrating an example of a blood flow dynamic map generated by the medical image processing apparatus 200 according to the embodiment. FIG. 9 shows an example of a type map in which colors are arranged by type based on the determination of benign / malignant TIC in FIG. As shown in the lower right of FIG. 9, the case of “benign” is indicated by light shading, the case of “suspecting malignancy” is indicated by diagonal lines, and the case of “suspecting malignancy strongly” is indicated by dark shading. As described with reference to FIG. 8, TIC is calculated for each pixel in the region of interest, and benign / malignant determination is performed. Therefore, each pixel is determined to be any type.

  Specifically, since it is determined that the pixel 1 is “suspected for malignancy” in FIG. 8, the corresponding upper left pixel is indicated by hatching. Similarly, since the pixel 5 is determined to be “highly suspected of malignancy”, the corresponding middle pixel in the middle stage is shown by dark shading. Since the pixel 9 is determined to be “benign”, the corresponding lower right pixel is indicated by light shading.

  Thus, according to the result determined based on TIC, each pixel is color-coded and a blood flow dynamic map for each type is generated. For example, “benign” is displayed in blue, “suspected malignant” in yellow, “strongly suspected malignant” is displayed in red, and the type can be visually observed by color.

  Further, in the example of FIG. 9, the type is determined for each pixel. However, based on the average value obtained by averaging the pixels of the regions of interest in each time phase included in the region of interest set, one region of interest is determined. One TIC may be calculated to determine the type. Further, among the types determined for each pixel of the region of interest in each phase included in the region of interest set, the most common type may be determined as a comprehensive type.

  FIG. 10 is a diagram illustrating a display example of a superimposed image displayed by the medical image processing apparatus 200 according to the embodiment. FIG. 10 shows an example of a superimposed image IMG1 obtained by superimposing the blood flow dynamic map exemplified in FIG. 9 on a medical image. In FIG. 10, the blood flow dynamic maps of the region of interest A and the region of interest B are displayed. As shown in the table T1, each hemodynamic map is a map classified by type, which is displayed by color-coding the pixels into three types of “benign”, “suspecting malignancy”, and “suspecting malignancy strongly”. It is. By displaying the blood flow dynamic map in the region of interest in this way, it is possible to determine what kind of lesion the high signal region observed in the region of interest is.

  The medical image on which the blood flow dynamic map is superimposed may be a specific one-time phase difference image of a medical image acquired by dynamic imaging, or a specific one-time T1-weighted image. Also good. Further, it may be a medical image acquired by an imaging protocol other than dynamic imaging. For example, by applying a strong intensity gradient magnetic field called a fat suppression image or image MPG (motion probing gradient) pulse, the phase shift due to the movement of the imaging target such as blood is emphasized, and the diffusion effect of the imaging target is emphasized. You may display on the diffusion coefficient map image which mapped the diffusion weighted image (DWI: Diffusion weighted image) which is an image, and an apparent diffusion coefficient (ADC: apparent diffusion coefficient). Further, the image may be displayed on a three-dimensional image called maximum intensity projection (MIP) or an arbitrary cross section generated from a three-dimensional image such as multi-planar reconstruction (MPR). . Further, it may be superimposed on a non-rigid registration image generated by non-rigid registration (non-linear registration). Non-rigid registration is a method of performing registration by a technique for deforming a medical image spatially and nonlinearly. In this way, by changing various medical images on which the blood flow dynamic map is superimposed, it is possible to observe the high signal region in various ways.

  FIG. 11 is a diagram illustrating another example of the blood flow dynamic map generated by the medical image processing apparatus 200 according to the embodiment. FIG. 10 illustrates an example in which the type-specific map illustrated in FIG. 9 is displayed, but the blood flow dynamic map displayed on the superimposed image is not limited to the type-specific map. From TIC, various values such as maximum intensity time, maximum intensity value, full width at half maximum value and average transit time can be calculated. Therefore, the blood flow dynamic map may be obtained by mapping these, and these maps may be displayed on the superimposed image.

  FIG. 11A shows an example in which the signal intensity value of each time phase obtained from the TIC is displayed numerically in the frame indicating each pixel of the region of interest A set shown in FIG. The variation of TIC varies from pixel to pixel, and the time phase at which the maximum intensity value is reached also varies from pixel to pixel. In FIG. 11A, the pixel having the maximum intensity value is indicated by dark shading. For example, from time phase 1 to time phase N of the region of interest A set in FIG. 11A, the signal intensity of the middle pixel (pixel 5) is “10”, “70”, “60”. 50 ". From such a change in signal strength, it can be seen that the signal strength is maximum at time phase 2 where the signal strength is 70. Similarly, the pixels indicated by dark shading in FIG. 11A are pixels indicating the maximum signal intensity value in all time phases.

  FIG. 11B shows an example of a superimposed image IMG2 in which a maximum signal intensity value map obtained by mapping a time phase in which each pixel indicates a maximum signal intensity value in FIG. 11A to each pixel is superimposed on a medical image. Yes. In the maximum signal intensity value map, a color corresponding to the time phase indicating the maximum signal intensity value is arranged. For example, the time phase at which the maximum signal intensity is obtained in the middle center pixel (pixel 5) in FIG. Time phase 2 corresponds to the shaded color as shown in table T2. The pixel (pixel 5) in the middle of the middle stage of the blood flow dynamic map of the region of interest A map in FIG.

  Further, the blood flow dynamic map displayed in the superimposed image may be made transparent or the color assignment may be changed. Further, only the color corresponding to the selected type or value may be displayed.

  FIG. 12 is a diagram illustrating another display example of the superimposed image displayed by the medical image processing apparatus 200 according to the embodiment. FIG. 12 illustrates a superimposed image IMG3 in which a type-specific blood flow dynamic map is superimposed on a DWI image. The graph G1 shows an example of a bar graph showing the maximum intensity value of the TIC of a certain pixel of the blood flow dynamic map of the region of interest B, the pixel value of the DWI image of the pixel, and the ADC value of the pixel. For example, as indicated by an arrow in the superimposed image IMG3 in FIG. 12, when a pixel having the region of interest B is designated via the input unit 220 or the like, the numerical value corresponding to the pixel may be displayed in a graph. Although an example in which a graph is displayed is shown in FIG. 12, for example, when the blood flow dynamic map is a type-specific map, a type corresponding to the selected pixel may be displayed. Further, as shown in FIG. 8, the TIC of the selected pixel may be displayed in a graph.

  Thus, the blood flow dynamic map displayed on the superimposed image can use various values obtained from the TIC. In addition, the blood flow dynamic map can be superimposed on various images such as diffusion-weighted images and three-dimensional images, and the user can comprehensively determine the region of interest based on the various values obtained from the TIC and the display of various medical images. Can be judged benign or malignant.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 MRI apparatus 100 Image pick-up part 200 Medical image processing apparatus 110 Static magnetic field magnet 120 Gradient magnetic field coil 130 Transmission coil 140 Reception coil 151 Bed apparatus 152 Top plate 11 Gradient magnetic field power supply apparatus 12 Bed control part 13 Transmission part 14 Reception part 15 Sequence control part 210 interface unit 220 input unit 230 display unit 240 image reconstruction unit 250 storage unit 260 control unit 251 image storage unit 261 region of interest setting unit 263 alignment processing unit 265 analysis unit 267 display control unit

Claims (7)

A plurality of regions of interest corresponding to each of a plurality of high signal regions are set in one of the medical images captured at a plurality of time phases, and each region of interest of the plurality of regions of interest set A region-of-interest setting unit that sets a region of interest having the same size and shape as the region of interest to a anatomically identical position by searching for a corresponding high-signal region in a medical image captured in a time phase; ,
A set of alignment images is generated for each region of interest corresponding to the anatomical position by aligning the regions of interest corresponding to the anatomical position with respect to the medical images captured in the plurality of time phases. An alignment processing unit;
For each region of interest corresponding to the anatomical position between the plurality of time phases, a time intensity curve based on a signal value indicated by a pixel of the region of interest corresponding between the plurality of time phases in the set of alignment images corresponding thereto. An analysis unit for generating a hemodynamic map based on the
A display controller that superimposes the blood flow dynamic map on at least one of the medical images captured at the plurality of time phases and displays the blood flow dynamic map on a display unit;
A medical image processing apparatus comprising: The hemodynamic map is a map according to type in which the result of determining the malignancy of the tumor based on the time intensity curve, a maximum intensity time map in which a time phase indicating the maximum intensity in the time intensity curve is mapped, or time Including one of the maximum intensity value maps that map the maximum intensity values in the intensity curve,
The medical image processing apparatus according to claim 1. The analysis unit generates the time intensity curve based on an average value obtained by averaging pixels included in each region of interest set in each time phase.
The medical image processing apparatus according to claim 1, wherein the medical image processing apparatus is a medical image processing apparatus. The display control unit changes the setting of the permeability of the blood flow dynamic map or the setting of color information of the blood flow dynamic map arranged based on the time intensity curve .
The medical image processing apparatus according to claim 1, wherein the medical image processing apparatus is a medical image processing apparatus. The display control unit generates a graph indicating a maximum intensity value of the time intensity curve corresponding to a pixel designated on the blood flow dynamic map or a graph indicating the time intensity curve ;
The medical image processing apparatus according to claim 1, wherein the medical image processing apparatus is a medical image processing apparatus. The display control unit converts the blood flow dynamic map into one of a differential image, a T1-weighted image, a maximum-value projection image, a diffusion-weighted image, a diffusion coefficient map image, a non-rigid registration image, or an arbitrary cross-sectional image of a three-dimensional image. To create a superimposed display,
The medical image processing apparatus according to claim 1, wherein the medical image processing apparatus is a medical image processing apparatus. An imaging unit for imaging medical images in a plurality of time phases;
A plurality of regions of interest corresponding to each of a plurality of high signal regions are set in one of the medical images captured at a plurality of time phases, and each region of interest of the plurality of regions of interest set A region setting unit that sets a region of interest having the same size and shape as the region of interest to a position that is anatomically identical by searching for a corresponding high signal region in a medical image captured in a time phase;
A set of alignment images is generated for each region of interest corresponding to the anatomical position by aligning the regions of interest corresponding to the anatomical position with respect to the medical images captured in the plurality of time phases. An alignment processing unit;
For each region of interest corresponding to the anatomical position between the plurality of time phases, a time intensity curve based on a signal value indicated by a pixel of the region of interest corresponding between the plurality of time phases in the set of alignment images corresponding thereto. An analysis unit for generating a hemodynamic map based on the
A display controller that superimposes the blood flow dynamic map on at least one of the medical images captured at the plurality of time phases and displays the blood flow dynamic map on a display unit;
An MRI apparatus characterized by comprising: