Medical image processing device and medical image diagnostic device

Abstract

To grasp the feature amount of an artery / portal vein blood flow ratio and the like of the whole of the liver.SOLUTION: A medical image processing apparatus according to an embodiment comprises an acquisition unit, a generation unit and a display control unit. The acquisition unit acquires feature amount data regarding the feature amount of a liver based on volume data of the liver. The generation unit generates a map obtained by projecting the feature amount data to a two-dimensional development having a plurality of display sections respectively corresponding to a plurality of liver areas determined on the basis of the blood vessel travel of the liver. The display control unit displays the map.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The embodiments disclosed in this specification and the drawings relate to a medical image processing apparatus and a medical image diagnostic apparatus. [Background technology]

[0002] The liver is an organ that receives dual blood circulation from an artery and a portal vein. In a healthy person, 20-30% of blood flow is received from the artery, and 70-80% of blood flow is received from the portal vein. However, when a person is ill, the ratio of blood flow between the artery and the portal vein (hereinafter referred to as the hepatic artery / portal vein blood flow ratio) differs. In a perfusion test, there is a technique for calculating the hepatic artery / portal vein blood flow ratio. The hepatic artery / portal vein blood flow ratio is presented by superimposing a color value or the like corresponding to the blood flow ratio on a slice cross section. However, with this presentation method, a user can only check the spatial distribution of the hepatic artery / portal vein blood flow ratio for each slice, and it takes a lot of time to check the hepatic artery / portal vein blood flow ratio of the entire liver. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-101482 A [Patent Document 2] JP 2012-217548 A Summary of the Invention [Problem to be solved by the invention]

[0004] One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to grasp the characteristic quantities, such as the arterial / portal blood flow ratio of the entire liver, in a short period of time. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described later can also be positioned as other problems. [Means for solving the problem]

[0005] A medical image processing apparatus according to an embodiment includes an acquisition unit, a generation unit, and a display control unit. The acquisition unit acquires feature amount data relating to feature amounts of the liver based on volume data of the liver. The generation unit generates a map in which the feature amount data is projected onto a two-dimensional development having a plurality of display sections corresponding to a plurality of liver segments determined based on the vascular course of the liver. The display control unit displays the map. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a medical image processing system including a medical image processing apparatus according to this embodiment. [Diagram 2] FIG. 2 is a diagram illustrating an example of the configuration of the medical image processing apparatus in FIG. [Diagram 3] FIG. 3 is a diagram showing a procedure of an example of processing by the medical image processing apparatus of FIG. [Figure 4] FIG. 4 is a schematic diagram showing the relationship between the liver segments and the portal vein. [Diagram 5] FIG. 5 is a diagram showing an example of a liver circular map, which is an example of a liver spread map. [Figure 6] FIG. 6 is a diagram showing a procedure for generating a circular liver map according to the first generation method. [Figure 7] FIG. 7 is a schematic diagram showing the relationship between liver segments, reference positions, and inflow points. [Figure 8] FIG. 8 is a diagram showing an example of a liver circular map template according to the first generation method. [Figure 9] FIG. 9 is a diagram showing a schematic diagram of a process for generating a circular liver map. [Figure 10] FIG. 10 is a diagram showing the steps of a second method for generating a circular liver map. [Figure 11] FIG. 11 is a schematic diagram showing liver segments, reference positions, inflow points and reference planes. [Figure 12] FIG. 12 is a diagram showing an example of a liver circular map template according to the second generation method. [Figure 13]FIG. 13 is a diagram for explaining another example of a method for arranging display sections according to the second generation method. [Figure 14] FIG. 14 is a diagram for explaining another example of a method for arranging display regions according to the second generation method. [Figure 15] FIG. 15 is a diagram showing a procedure for generating a circular liver map according to the third generation method. [Figure 16] FIG. 16 is a schematic diagram showing liver segments, reference positions, inflow points and sizes of liver segments. [Figure 17] FIG. 17 is a diagram showing an example of an intermediate stage of a liver circular map template according to the third generation method. [Figure 18] FIG. 18 is a diagram showing an example of a template of a liver circular map according to the generation method of FIG. [Figure 19] FIG. 19 is a diagram showing an example of an intermediate stage of another liver circular map template according to the third generation method. [Figure 20] FIG. 20 is a diagram showing an example of a template of a liver circular map according to the generation method of FIG. [Figure 21] FIG. 21 is a diagram showing an example of a display screen according to the first display example. [Figure 22] FIG. 22 is a diagram showing an example of a display screen according to the second display example. [Figure 23] FIG. 23 is a diagram showing another example of the display screen according to the display example 2. In FIG. [Figure 24] FIG. 24 is a diagram showing an example of a display screen according to the third display example. [Diagram 25] FIG. 25 is a diagram showing another example of the display screen according to the display example 3. In FIG. [Figure 26] FIG. 26 is a diagram showing another example of the display screen according to the display example 3. In FIG. [Figure 27] FIG. 27 is a diagram showing an example of superimposing a circular liver map and a blood vessel region according to the fourth display example. [Figure 28] FIG. 28 is a diagram showing an example of superimposing a circular liver map, a blood vessel region, and a tumor region according to the fourth display example. [Figure 29]FIG. 29 is a diagram showing an example of a display screen according to the fifth display example. [Diagram 30] FIG. 30 is a diagram showing an example of a display screen according to the sixth display example. [Diagram 31] FIG. 31 is a diagram showing an example of a liver circular map (hepatic segment resection) according to the seventh display example. [Diagram 32] FIG. 32 is a diagram showing another example of the liver circular map according to the seventh display example (without liver segment color). [Diagram 33] FIG. 33 is a diagram showing another example of the liver circular map according to the seventh display example (liver segments displayed with dotted lines). [Diagram 34] FIG. 34 is a diagram showing another example (reconstruction) of the liver circular map according to the seventh display example. [Diagram 35] FIG. 35 is a diagram showing an example of a display screen according to the eighth display example. [Diagram 36] FIG. 36 is a diagram showing an example of a liver spread map according to the first modification. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, embodiments of a medical image processing apparatus and a medical image diagnostic apparatus will be described in detail with reference to the drawings.

[0008] FIG. 1 is a diagram showing an example of the configuration of a medical image processing system including a medical image processing device according to the present embodiment. As shown in FIG. 1, the medical image processing system includes a medical image processing device 1, a medical image diagnostic device 2, and a medical image storage device 3, which are communicatively connected to each other via a network. The medical image processing device 1 is a computer that processes medical images such as liver volume data (three-dimensional medical image data) related to a subject. The medical image diagnostic device 2 is a computer system including a medical imaging mechanism and a computer that performs medical imaging on an imaging region including the liver of the subject to generate liver volume data. The medical image storage device 3 is a computer that stores medical images generated by the medical image processing device 1, the medical image diagnostic device 2, and the like. The medical image storage device 3 is realized by a computer included in a network system such as a PACS (Picture Archiving and Communication System), a HIS (Hospital Information System), or a RIS (Radiology Information System).

[0009] The medical image diagnostic device 2 may be a single-modality device such as an X-ray computed tomography device (X-ray CT device), a magnetic resonance imaging device (MRI device), an X-ray diagnostic device, a PET device, a SPECT device, or an ultrasound diagnostic device, or may be a multi-modality device such as a PET / CT device, a SPECT / CT device, a PET / MRI device, or a SPECT / MRI device.

[0010] When the medical image diagnostic device 2 is an X-ray CT device, the stand of the X-ray CT device rotates the X-ray tube and the X-ray detector around the subject, irradiating the subject with X-rays from the X-ray tube, and the X-rays that pass through the subject are detected by the X-ray detector. The X-ray detector generates an electrical signal having a peak value according to the detected X-ray dose. The electrical signal is subjected to signal processing such as A / D conversion by a data acquisition circuit. The electrical signal after A / D conversion is called projection data or sinogram data. The console generates a CT image based on the projection data or sinogram data. The projection data and sinogram data are types of raw data. The CT image is a type of medical image.

[0011] When the medical image diagnostic device 2 is an MRI device, the gantry of the MRI device repeatedly applies a gradient magnetic field via a gradient magnetic field coil and an RF pulse via a transmission coil under the application of a static magnetic field via a static magnetic field magnet. An MR signal is emitted from the subject due to the application of the RF pulse. The emitted MR signal is received via a receiving coil. The received MR signal is subjected to signal processing such as A / D conversion by a receiving circuit. The MR signal after A / D conversion is called k-space data. The console generates an MR image based on the k-space data. The k-space data is a type of raw data. The MR image is a type of medical image.

[0012] When the medical image diagnostic device 2 is an ultrasound diagnostic device, an ultrasound probe of the ultrasound diagnostic device transmits ultrasound beams from a plurality of ultrasound transducers into the subject's body, and receives ultrasound reflected from within the subject's body via the ultrasound transducers. The ultrasound transducers generate electrical signals having peak values ​​corresponding to the sound pressure of the received ultrasound. The electrical signals are A / D converted by an A / D converter provided in the ultrasound probe or the like. The electrical signals after A / D conversion are called echo data. The device body generates an ultrasound image based on the echo data. Echo data is a type of raw data. The ultrasound image is a type of medical image.

[0013] When the medical image diagnostic device 2 is a PET device, the gantry of the PET device generates digital data having digital values ​​related to the energy value and detection position of the pair of gamma rays by simultaneously measuring a pair of 511 keV gamma rays generated by the annihilation of a positron generated from a radioactive nuclide accumulated in the subject and an electron present around the radioactive nuclide using a coincidence measurement circuit. The digital data is called coincidence data or sinogram data. The console generates a PET image based on the coincidence data or sinogram data. The coincidence data and sinogram data are types of raw data. The PET image is a type of medical image. The same applies to a SPECT device.

[0014] When the medical image diagnostic device 2 is an X-ray diagnostic device, the X-ray diagnostic device generates X-rays from an X-ray tube provided in a C-arm. An X-ray detector such as an FPD (Flat Panel Display) provided in the C-arm or independent of the C-arm receives X-rays generated from the X-ray tube and transmitted through the subject. The X-ray detector generates an electric signal having a peak value according to the detected X-ray dose, and performs signal processing such as A / D conversion on the electric signal. The electric signal after A / D conversion is called projection data or an X-ray image. In the case of a cone beam CT or the like, the projection data or the X-ray image is also used as raw data. An X-ray image is a type of medical image.

[0015] Fig. 2 is a diagram showing an example of the configuration of the medical image processing apparatus 1 in Fig. 1. As shown in Fig. 2, the medical image processing apparatus 1 has a processing circuit 11, a communication interface 12, a display device 13, an input interface 14, and a storage device 15.

[0016] The processing circuit 11 has a processor such as a CPU (Central Processing Unit). The processor executes programs for implementing the image processing function 111, the feature amount acquisition function 112, the map generation function 113, and / or the display control function 114. The programs for implementing the image processing function 111, the feature amount acquisition function 112, the map generation function 113, and / or the display control function 114 may be recorded in a non-transitory recording medium readable by a processor such as the storage device 15. Each of the functions 111-114 is not limited to being implemented by a single processing circuit. A processing circuit may be configured by combining a plurality of independent processors, and each processor may implement each of the functions 111-114 by executing a program.

[0017] By implementing the image processing function 111, the processing circuitry 11 performs various image processing on medical images such as volume data of the liver of a subject. The image processing can include image correction, image conversion, image processing, feature extraction, image recognition, and three-dimensional image processing.

[0018] By implementing the feature amount acquisition function 112, the processing circuitry 11 acquires data on the feature amount of the liver (hereinafter referred to as feature amount data) based on the volume data of the liver of the subject. For example, a parameter on the blood flow of the liver is used as the feature amount. The feature amount data is data in which a feature amount is assigned to the entire volume data or a partial area including the liver.

[0019] By implementing the map generating function 113, the processing circuitry 11 generates a map by projecting the feature data acquired by the feature acquiring function 112 onto a two-dimensional development (template) having a plurality of display sections corresponding to a plurality of liver segments determined based on the blood vessels running through the liver. The processing circuitry 11 generates a template using the blood vessels inside the liver as the reference positions, and projects the feature data onto the template. This generates the map. Hereinafter, the generated map will be referred to as a liver development map.

[0020] By implementing the display control function 114, the processing circuitry 11 displays various information. For example, the processing circuitry 11 displays the liver spread map generated by the map generation function 113 on the display device 13.

[0021] The communication interface 12 is an interface that connects to the medical image diagnostic apparatus 2, the medical image storage apparatus 3, the PACS, the HIS, the RIS, etc. via a LAN (Local Area Network) etc. The communication interface 12 transmits and receives various information to and from the connected devices.

[0022] The display device 13 displays various information in accordance with the display control function 114 of the processing circuit 11. As the display device 13, a liquid crystal display (LCD), a cathode ray tube (CRT) display, an organic electroluminescence display (OELD), a plasma display, or any other display may be appropriately used. The display device 13 may also be a projector.

[0023] The input interface 14 accepts various input operations from a user, converts the accepted input operations into electrical signals, and outputs the electrical signals to the processing circuit 11. Specifically, the input interface 14 is connected to input devices such as a mouse, a keyboard, a trackball, a switch, a button, a joystick, a touchpad, and a touch panel display. The input interface 14 outputs electrical signals corresponding to the input operations to the input devices to the processing circuit 11. The input devices connected to the input interface 14 may be input devices provided in other computers connected via a network or the like. The input interface 14 may be a voice recognition device that converts a voice signal collected by a microphone into an instruction signal.

[0024] The storage device 15 is a storage device such as a ROM (Read Only Memory), a RAM (Random Access Memory), an HDD (Hard Disk Drive), an SSD (Solid State Drive), or an integrated circuit storage device that stores various information. The storage device 15 stores, for example, medical images and various programs. In addition to the above storage devices, the storage device 15 may be a portable storage medium such as a CD (Compact Disc), a DVD (Digital Versatile Disc), or a flash memory, or a drive device that reads and writes various information between a semiconductor memory element, etc. The storage device 15 may be in another computer connected to the medical image processing device 1 via a network.

[0025] Next, a processing example of the medical image processing apparatus 1 will be described.

[0026] FIG. 3 is a diagram showing a procedure of a processing example of the medical image processing device 1. As shown in FIG. 3, the processing circuit 11 extracts a liver region, a hepatic artery region, and a portal vein region from the time-series volume data of the liver by implementing the image processing function 111 (step SA1). The time-series contrast volume data of the liver (three-dimensional medical image data) may be generated by any of the above medical image diagnostic devices 2, but is assumed to be generated by an X-ray computed tomography apparatus. In this case, the X-ray computed tomography apparatus repeatedly scans the abdominal region including the liver of the subject for an arbitrary imaging period, for example, after a contrast agent is injected into the subject. The imaging period includes a plurality of time phases during which the contrast agent flows in the liver. The imaging period may be set in advance as an imaging condition, or may be dynamically determined during the imaging period. The X-ray computed tomography apparatus repeatedly scans to collect time-series volume data of the abdominal region including the liver over the imaging period. The volume data is called time-series contrast volume data.

[0027] In step SA1, the processing circuitry 11 extracts the liver region, the hepatic artery region, and the portal vein region from the time-series contrast volume data using existing image processing such as threshold processing, texture analysis, landmark analysis, image recognition processing, etc. The liver region is an image region related to the image, the hepatic artery region is an image region related to the hepatic artery, and the portal vein region is an image region related to the portal vein. The liver region, the hepatic artery region, and the portal vein region may be extracted manually in accordance with a user instruction via the input interface 14. Extraction of these regions may be performed on volume data of all time phases of the time-series contrast volume data, or on volume data of some time phases.

[0028] After step SA1 is performed, the processing circuitry 11 divides the liver region into a plurality of liver segments by implementing the image processing function 111 (step SA2). In step SA2, the processing circuitry 11 divides the liver region into a plurality of liver segments based on the vascular course of the portal vein region and / or the hepatic artery region. Any liver segments such as Healey & Schroy's liver segments or Couinaud's liver segments may be used, but in the following description, Couinaud's liver segments will be used.

[0029] As shown in FIG. 4, the liver is divided into sub-segments, including the caudate lobe S1, the left lobe lateral posterior segment S2, the left lobe lateral anterior segment S3, the left lobe medial segment S4, the right lobe anterior inferior segment S5, the right lobe posterior inferior segment S6, the right lobe posterior superior segment S7, and the right lobe anterior superior segment S8. The portal vein is connected to the liver segments S1-S8. The root of the portal vein is called the portal vein main frame. The processing circuitry 11 divides the liver region into eight liver segments based on the positional relationship between the vascular course of the portal vein region and / or the hepatic artery region and the liver region, using image recognition processing or the like. The processing circuitry 11 may divide the liver segments according to an instruction from a user via the input interface 14.

[0030] As shown in FIG. 3, when step SA2 is performed, the processing circuitry 11 acquires feature data by implementing the feature acquisition function 112 (step SA3). In step SA3, the processing circuitry 11 performs perfusion analysis on the time-series contrast volume data, and calculates parameters related to blood flow in the liver (hereinafter referred to as liver blood flow parameters) as liver features for each pixel of the liver region of the time-series contrast volume data. Specifically, the processing circuitry 11 calculates a hepatic artery blood flow rate, which is the blood flow rate flowing from the hepatic artery to the liver, and a portal vein blood flow rate, which is the blood flow rate flowing from the portal vein to the liver, for each pixel of the liver region. Then, the processing circuitry 11 calculates a hepatic artery / portal vein blood flow ratio, which is the ratio between the hepatic artery blood flow rate and the portal vein blood flow rate, for each pixel. Data on the spatial distribution of the portal vein blood flow rate, hepatic artery blood flow rate, and hepatic artery / portal vein blood flow ratio for each pixel is acquired as feature data.

[0031] The feature amount data does not necessarily need to be calculated by the processing circuitry 11, and may be calculated by another computer based on the time-series contrast volume data of the liver of the subject by the above-mentioned method, for example. In this case, the processing circuitry 11 may obtain the feature amount data from the other computer via the communication interface 12, etc. In addition, the feature amount is not limited to the liver blood flow parameter, and may be any analysis parameter obtained from the volume data, such as the amount of fat in the liver.

[0032] After step SA3, the processing circuitry 11 generates a liver unfolded map by implementing the map generating function 113 (step SA4). In step SA4, the processing circuitry 11 projects the feature data (e.g., liver blood flow parameters) acquired in step SA3 onto a two-dimensional unfolded view (template) having a plurality of display sections corresponding to a plurality of liver segments S1-S8 determined based on the vascular course of the liver, to generate a liver unfolded map. On the liver unfolded map, the feature data of the entire liver region is projected. As the liver unfolded map, for example, a liver circular map is generated.

[0033] FIG. 5 is a diagram showing an example of a liver circular map I1, which is an example of a liver spread map. The liver circular map is a two-dimensional map in which feature data is projected onto a circular template in which the reference position of the portal vein region corresponds to the center point. As an example, the liver portal area is used as the reference position. In the liver circular map template, a plurality of display sections S1-S8 corresponding to the plurality of liver segments S1-S8 are arranged around a center point according to the positional relationship of each of the plurality of liver segments S1-S8 with respect to the reference position. The processing circuitry 11 determines the arrangement of the plurality of display sections S1-S8 in the template based on the distance and / or direction between the reference position and the plurality of liver segments S1-S8. The processing circuitry 11 can also determine the size of each of the plurality of display sections S1-S8 based on the size of each of the plurality of liver segments S1-S8. Note that the positional relationship and / or size of each display section S1-S8 may be a preset standard value regardless of the subject to be examined.

[0034] As shown in FIG. 5, each display section S1-S8 has a circular or sector shape. A circular template is formed by pasting together a plurality of display sections S1-S8 according to the positional relationship of the plurality of liver segments S1-S8. The liver circular map template is expressed in a coordinate system similar to polar coordinates. The coordinate system is expressed as (r, θ), where θ roughly reflects the angle around the portal vein core line passing through the reference position of the portal vein region, and r reflects the distance from the reference position. The liver circular map can also be expressed as a liver polar map. Details of the method for generating the liver unfolded map and the liver circular map will be described later. In this embodiment, the reference position is set on the portal vein region, but is not limited to this, and may be set on the hepatic artery region.

[0035] When step SA4 is performed, the processing circuitry 11 displays the liver unfolded map generated in step SA4 (step SA5) by implementing the display control function 114. In step SA5, the processing circuitry 11 displays the liver unfolded map on the display device 13 in various layouts.

[0036] As shown in FIG. 5, the processing circuit 11 displays the liver unfolded map in a color according to the feature value. The correspondence between the feature value and the color value is registered in a color table. For example, the feature value and the color value are associated with each other so that the feature value changes continuously from red to green to blue as it goes from high to low. The processing circuit 11 displays a liver circular map I11 that expresses the spatial distribution of the feature value by color by referring to the color table. The liver circular map I11 is a map in which the feature value of the entire liver is projected onto a two-dimensional plane for each liver segment, so that the user can observe and grasp the spatial distribution of the feature value of the entire liver at a glance by observing the liver circular map I11. Note that the feature value may be associated with other display parameter values ​​such as gray value, transparency, etc. instead of color value.

[0037] When step SA5 is performed, the processing of the medical image processing apparatus 1 ends.

[0038] Next, a method for generating the liver circular map in step SA4 of FIG. 3 will be described in detail.

[0039] (First generation method) Fig. 6 is a diagram showing a procedure for generating a circular liver map according to the first generation method. As shown in Fig. 6, the processing circuitry 11 sets a reference position in the portal vein region extracted in step SA1 (step SB1). As shown in Fig. 7, the reference position P0 is set at a branch point of the portal vein main frame that passes through the center line of the portal vein region. The reference position P0 may be set by image processing, or may be set at a position designated by the user via the input interface 14.

[0040] When step SB1 is performed, the processing circuit 11 calculates the distance between each liver segment and the reference position (step SB2). As the distance between each liver segment and the reference position, for example, as shown in FIG. 7, the portal vein center line length from the reference position P0 to the inflow points P1-P8 of each liver segment S1-S8 may be calculated. The inflow points P1-P8 are set at points where the portal vein region enters the liver segments S1-S8. The inflow points P1-P8 may be set by image processing, or may be set at positions designated by the user via the input interface 14. The portal vein center line length is defined as the length of the center line (center line) of the portal vein region.

[0041] The distance between each liver segment and the reference position may be calculated as a straight-line distance from the reference position to each inflow point. As another example, the distance between each liver segment and the reference position may be calculated as a length from the reference position to a representative point of each liver segment. The representative point may be set to the center of gravity, center point, or designated point of the liver segment. The length may be a straight-line distance, a portal vein center line length, or a combination of a straight-line distance and a portal vein center line length.

[0042] When step SB2 is performed, the processing circuitry 11 generates a template of a circular liver map (step SB3). More specifically, the processing circuitry 11 generates a circular template in which a plurality of display sections are arranged according to the distance calculated in step SB2, with the reference position set in step SB1 as the center point. Step SB3 will be specifically described below.

[0043] As shown in Fig. 8, the template of the liver circular map is divided into an inner region and an outer region in the radial direction. The processing circuit 11 compares the distance calculated in step SB2 with a threshold value, and places the display area corresponding to the liver segment that is closer than the threshold value in the inner region, and the display area corresponding to the liver segment that is closer than the threshold value in the outer region. The display area in the inner region has a fan shape, and the display area in the outer region has a circular ring shape. The multiple display areas in the inner region and the multiple display areas in the outer region are pasted together to form a circular template.

[0044] In FIG. 8, for example, the liver segments S2, S3, S6, and S7 are located at a distance longer than the threshold, so the display segments S2, S3, S6, and S7 are arranged in the outer region, and the liver segments S1, S4, S5, and S8 are located at a distance shorter than the threshold, so the display segments S1, S4, S5, and S8 are arranged in the inner region. The positional relationship between the display segments S2, S3, S6, and S7 in the outer region and the positional relationship between the display segments S1, S4, S5, and S8 in the inner region are set in advance according to the positional relationship between the liver segments. The sizes of the display segments S2, S3, S6, and S7 in the outer region are set to be equal, and the sizes of the display segments S1, S4, S5, and S8 in the inner region are also set to be equal. In FIG. 8, the display segments S2, S3, S6, and S7 and the display segments S1, S4, S5, and S8 are arranged alternately in the circumferential direction, but they may be arranged to coincide in the circumferential direction.

[0045] When step SB3 is performed, the processing circuit 11 projects the feature data for each of the liver segments S1-S8 onto a template of the liver circular map to generate a liver circular map (step SB4). In step SB4, the processing circuit 11 develops each of the liver segments S1-S8 on a cut surface according to the running direction of the portal vein region connected to the liver segment, associates each first pixel of the cut surface in the developed liver segment with each second pixel of the display section corresponding to the liver segment, and assigns the projected feature value of a projection line that is perpendicular to the cut surface, passes through the first pixel, and penetrates the developed liver segment to the second pixel of the display section. This generates a liver circular map. Step SB4 will be specifically described below. Note that the following description of step SB4 will be given for the process for the liver segment S7 as an example, but the other liver segments can be processed in the same manner.

[0046] As shown in FIG. 9, first, the processing circuit 11 sets a cutting surface 71 in the liver segment 70. The cutting surface 71 is set so as to follow the center line 72 of the portal vein region connected to the liver segment 70. Specifically, the cutting surface 71 is set on a surface that cuts from one surface of the liver segment along the center line 72 and reaches the center line 72. Here, an end P71 of the center line 72 that passes through the liver segment 70 is called an end point. The cutting surface 71 is defined as a surface surrounded by a line segment that connects the inflow point P7 and the end point P71 along the center line 72 and a line segment that connects the inflow point P7 and the end point P71 along the surface of the liver segment 70. When the cutting surface 71 is set, the processing circuit 11 cuts the liver segment 70 along the cutting surface 71 and develops it.

[0047] After the development, the processing circuit 11 performs correspondence between anatomically corresponding pixels in the developed liver segment 70 and the display section 75 corresponding to the liver segment 70. More specifically, the processing circuit 11 performs correspondence between each pixel on the cut surface 71 of the developed liver segment 70 and each pixel of the display section 75. For example, first, a point on the contour 73 of the cut surface 71 of the liver segment 70 is corresponded to a point on the contour 76 of the display section 75. Here, the correspondence is performed such that a center point 761 of the radial inner edge of the display section 75 coincides with an inflow point P7 of the liver segment 70, and a center point 762 of the radial outer edge of the display section 75 coincides with an end point P71 of the liver segment 70. In addition, one end point 763 and the other end point 764 of the radially inner edge of the display area 75 respectively coincide with one end point P72 and the other end point P73 of the inflow point P7 side edge of the cross section 71, and one end point 765 and the other end point 766 of the radially outer edge of the display area 75 respectively coincide with one end point P74 and the other end point P75 of the end point P71 side edge of the cross section 71.

[0048] Next, the processing circuit 11 calculates the correspondence between the pixels in the cross section 71 and the pixels in the display area 75 based on the correspondence between the contour points. As described above, the display area 75 is defined in a two-dimensional coordinate system obtained by performing a coordinate transformation according to the correspondence on the two-dimensional coordinate system related to the cross section 71. In the two-dimensional coordinate system, the angle around the center point of the template is defined as the distance from the core line 72 or the inflow point P7 on a plane (hereinafter referred to as the inflow plane) passing through the inflow point P7 of the liver segment 70, and the radial distance of the template is defined as the distance along the core line 72 from the inflow point P7. In this way, the display area 75 is defined in a coordinate system similar to a polar coordinate system.

[0049] The correspondence (mapping) of each image of the liver segment 70 to the corresponding pixel of the display section 75 forms a coordinate transformation formula. The coordinate transformation formula is derived for each of the liver segments S1-S8. The coordinate transformation formula is stored in the storage device 15 or the like in correspondence with the identifier of the liver segments S1-S8.

[0050] After the correspondence, the processing circuitry 11 sets a projection line 77 for each pixel 701 on the cross section 71, which passes through the pixel 701, is perpendicular to the cross section 71, and penetrates the liver segment 70. A projection value is calculated based on a plurality of feature values ​​assigned to the plurality of pixels 701 through which the projection line 77 passes. As the projection value, any statistical value according to the purpose may be calculated, such as an average value, an integral value, a minimum value, a maximum value, etc. of the plurality of feature values ​​assigned to the plurality of pixels 701 through which the projection line 77 passes. The type of statistical value can be specified by the user via the input interface 14. Then, the processing circuitry 11 assigns the calculated projection value to the corresponding pixel 78 in the display section 75. In this way, a circular liver map is generated.

[0051] When step SB4 is performed, the process of generating a circular liver map by the processing circuitry 11 (step SA4) ends.

[0052] As described above, according to the first generation method, it is possible to generate a circular liver map in which the spatial distribution of the feature amount of the entire liver is expanded on a two-dimensional circular plane while maintaining the positional relationship between the liver segments based on the portal vein region. By observing the circular liver map, the user can check the spatial distribution of the feature amount of the entire liver at a glance. For example, if the feature amount is a liver blood flow parameter such as a hepatic artery / portal vein blood flow ratio, the user can instantly evaluate the blood flow abnormality. In addition, the first generation method determines the arrangement of the display sections on the template of the circular liver map based only on the distance between the reference position and each liver segment. Therefore, according to the first generation method, the display sections can be arranged almost uniformly regardless of the individual differences of the subjects, compared to the second and third generation methods that take into account the direction, and the circular liver map can be generated easily and with a low calculation load. In addition, since the arrangement of the display sections is almost uniform, it is easy to observe the circular liver map across multiple subjects.

[0053] In the above embodiment, the arrangement of the display sections on the template is determined according to the distance between the reference position and each liver segment. However, the arrangement of the display sections may be determined according to anatomical knowledge and experience. More specifically, in the above embodiment, the display sections corresponding to the liver segments whose distance is below the threshold are arranged in the inner region, and the display sections corresponding to the liver segments whose distance is above the threshold are arranged in the outer region, but the display sections arranged in the inner region and the outer region may be determined according to anatomical knowledge and experience.

[0054] (Second generation method) Fig. 10 is a diagram showing a procedure for generating a circular liver map according to the second generating method. The second generating method 2 is an advanced version of the first generating method. As shown in Fig. 10, the processing circuit 11 sets a reference position of the portal vein region extracted in step SA1 (step SC1). The process of step SC1 is similar to the process of step SB1.

[0055] After step SC1 is performed, the processing circuit 11 calculates the distance and direction between each liver segment and the reference position (step SC2). The distance between each liver segment and the reference position is calculated in the same manner as in step SB2. The direction between each liver segment and the reference position is calculated as the left or right direction with respect to a plane (hereinafter referred to as the reference plane) that passes through the reference position. For example, it is calculated as follows.

[0056] As shown in FIG. 11, the processing circuit 11 calculates whether each inflow point P1-P8 of each liver segment S1-S8 is on the left or right side of the reference plane 60 when viewed from an arbitrary line of sight. The direction of the liver segment with the inflow point on the left side is calculated as "left", and the direction of the liver segment with the inflow point on the right side is calculated as "right". Specifically, a vector from the reference position P0 to each inflow point P1-P8 is calculated, and the direction of each vector is compared with the direction of the reference plane 60. Then, the liver segment related to the vector on the left side of the reference plane 60 is classified as the "left" direction, and the liver segment related to the vector on the right side is classified as the "right" direction. In this way, the direction differs depending on the line of sight. For example, in the case of FIG. 11, the liver segments S5-S8 are identified as the direction "left", and the liver segments S1-S4 are identified as the direction "right". The line of sight direction may be set in advance, or may be specified by the user via the input interface 14.

[0057] After step SC2, the processing circuitry 11 generates a template of a liver circular map (step SC3). More specifically, the processing circuitry 11 generates a template in which a plurality of display sections are assigned according to the distance and direction calculated in step SC2, centered on the reference position set in step SC1. Step SC3 will be specifically described below.

[0058] As shown in Fig. 12, similarly to step SB3, each display section is divided into an inner region or an outer region according to the distance between each liver segment and the reference position. Then, for each of the inner region and the outer region, each display section is arranged according to the direction calculated in step SC3. For example, when display sections S1, S4, S5, and S8 are divided into the inner region, and the directions of the display sections S1, S4, S5, and S8 are "right", "right", "left", and "left", respectively, the display sections S1 and S4 are arranged on the left side of the inner region, and the display sections S6 and S8 are arranged on the right side. The same is true for the outer region.

[0059] After step SC3, the processing circuitry 11 projects the feature data for each of the liver segments S1-S8 onto a template to generate a liver circular map (step SC4). The process of step SC4 may be performed in the same manner as the process of step SB4.

[0060] When step SC4 is performed, the process of generating the liver circular map by the processing circuitry 11 ends.

[0061] Note that the above procedure is merely an example, and the present embodiment is not limited to this. For example, the method of arranging the display sections in step SC3 is not limited to the above method.

[0062] In step SC3, the processing circuitry 11 sets an axial section 62 intersecting the liver region 61 as shown in Fig. 13. The axial section 62 corresponds to the surface of the template. The processing circuitry 11 projects the inflow points P1-P8 of the liver segments S1-S8 onto the axial section 62, and determines the arrangement of each display section S1-S8 in the template according to the positional relationship of the inflow points P1-P8 projected onto the axial section 62.

[0063] The projection destination of the inflow points P1-P8 of the liver segments S1-S8 is not limited to the axial cross section 62. For example, as shown in Fig. 14, the processing circuitry 11 may project the inflow points P1-P8 onto a plane 63 that is perpendicular to the reference plane 60 and intersects with the liver region 61. The processing circuitry 11 determines the arrangement of each display section S1-S8 in the template according to the positional relationship of the inflow points P1-P8 projected onto the plane 63.

[0064] As described above, the second generation method determines the layout of the display sections on the template of the circular liver map based on the distance and direction between the reference position and each liver segment. Therefore, compared to the first generation method, the second generation method can generate a circular liver map that reflects individual differences of subjects. This makes it possible to accurately grasp the spatial distribution of feature quantities such as liver blood flow parameters of each subject.

[0065] (Third Generation Method) Fig. 15 is a diagram showing a procedure for generating a liver circular map according to the third generation method. As shown in Fig. 15, the processing circuitry 11 sets a reference position of the portal vein region extracted in step SA1 (step SD1). The process of step SD1 is similar to the process of step SB1.

[0066] After step SD1 is performed, the processing circuit 11 calculates the distance and direction between each liver segment and the reference position (step SD2). The processing of step SD2 is similar to the processing of step SC2.

[0067] After step SD2, the processing circuitry 11 generates a template of a circular map of the liver (step SD3). The process of step SD3 is similar to the process of step SC3.

[0068] After step SD3, the processing circuit 11 determines the size of each display section according to the size of each liver segment (step SD4). The size of each liver segment is determined by the area or volume of the liver segment. For example, as shown in FIG. 16, the area may be determined by the area of ​​the surface (inflow surface) A1-A8 to which the portal vein region of each liver segment is connected.

[0069] As shown in FIG. 17, in step SD3, the display sections S6 and S7 are assigned to the outer left region of the template, the display sections S2 and S3 are assigned to the outer right region, the display sections S5 and S8 are assigned to the inner left region, and the display sections S1 and S4 are assigned to the inner right region. In this case, as shown in FIG. 18, the processing circuit 11 makes the area ratio of the two display sections in each of the above regions of the template coincide with the size ratio of the corresponding two liver segments. For example, when the size ratio of the liver segment S6 to the liver segment S7 is 3:2, the processing circuit 11 determines the area ratio of the display section S6 to the display section S7 in the outer left region of the template to 3:2, as shown in FIG. 18. The arrangement of the display section S6 to the display section S7 in the outer left region is determined in advance according to the anatomical positions of the liver segment S6 and the liver segment S7. The area ratio of the other display sections in the template may be determined in the same manner.

[0070] In step SD2, the direction may not be calculated, and only the distance may be calculated. In the case where only the distance is calculated, in step SD3, a plurality of display sections are selectively assigned to each of the outer region and the inner region. For example, as shown in FIG. 19, the display sections S2, S3, S6, and S7 are assigned to the outer region of the template, and the display sections S1, S4, S5, and S8 are assigned to the inner region. Even in this case, the processing circuit 11 matches the area ratio of the four display sections in each of the above regions of the template to the size ratio of the corresponding four liver segments, as in the above method. For example, as shown in FIG. 20, the processing circuit 11 matches the area ratio of the display sections S2, S3, S6, and S7 in the outer region to the area ratio of the liver segments S2, S3, S6, and S7. The arrangement of the display sections S2, S3, S6, and S7 in the outer region is determined in advance according to the anatomical positions of the liver segments S2, S3, S6, and S7.

[0071] After step SD4, the processing circuitry 11 projects the feature data for each of the liver segments S1-S8 onto a template to generate a circular liver map (step SD5). The process of step SD5 may be performed in the same manner as the process of step SB4.

[0072] When step SD5 is performed, the process of generating a circular liver map by the processing circuit 11 is completed.

[0073] As described above, the third generation method determines the layout of the display sections on the template of the circular liver map based on the distance and direction between the reference position and each liver segment, and the size of each liver segment. Therefore, compared with the first and second generation methods, the third generation method can generate a circular liver map that reflects the individual differences of subjects. This makes it possible to accurately grasp the spatial distribution of feature quantities such as liver blood flow parameters of each subject.

[0074] Next, various examples of displaying the liver circular map by the display control function 114 will be described. Note that the distribution of gray shading in the figure corresponds to the distribution of the feature value or liver blood flow parameter value, but is added to help understand the liver circular map, and does not have any clinical meaning unless otherwise specified.

[0075] (Display example 1) FIG. 21 is a diagram showing an example of a display screen IS1 according to the display example 1. As shown in FIG. 21, the processing circuit 11 displays a liver circular map I2 related to the hepatic artery / portal blood flow ratio and a color bar I3 side by side on the display screen IS1. In the liver circular map I2, a color value according to the hepatic artery / portal blood flow ratio is assigned to each pixel, and the liver circular map I2 is displayed in a color according to the color value. As described above, the liver circular map I2 represents the spatial distribution of the hepatic artery / portal blood flow ratio of the entire liver on one plane by dividing it into liver segments, so that the user can check the spatial distribution of the hepatic artery / portal blood flow ratio of the entire liver at a glance by observing the color distribution on the liver circular map I2, and can instantly evaluate the blood flow abnormality.

[0076] 21, the color bar I3 is a graphic representation of the correspondence between the hepatic artery / portal blood flow ratio and a color value or color. The liver circular map I2 and the color bar I3 are displayed side by side, allowing the user to instantly associate the color with the hepatic artery / portal blood flow ratio.

[0077] (Display example 2) The processing circuit 11 according to the second display example displays two liver circular maps side by side based on at least two feature data items: portal vein blood flow, arterial blood flow, the ratio between portal vein blood flow and arterial blood flow, and fat mass.

[0078] FIG. 22 is a diagram showing an example of a display screen IS2 according to a display example 2. As shown in FIG. 22, the processing circuit 11 displays a liver circular map I4 related to portal vein blood flow and a liver circular map I5 related to hepatic artery blood flow side by side on the display screen IS2. The liver circular map I4 is assigned a color value according to the portal vein blood flow and is displayed in a color according to the color value. The liver circular map I5 is assigned a color value according to the hepatic artery blood flow and is displayed in a color according to the color value. A color bar I6 is displayed next to the liver circular map I4. The color bar I6 indicates the correspondence between the portal vein blood flow and the color value or color, and the color bar I7 indicates the correspondence between the hepatic artery blood flow and the color value or color.

[0079] By displaying the liver circular map I4 and the liver circular map I5 side by side, the user can grasp the portal vein blood flow and the hepatic artery blood flow in the entire liver at a glance.

[0080] In addition, as shown in FIG. 23, the processing circuit 11 may display only one of the liver circular map I4 and the liver circular map I5. In this case, the processing circuit 11 may switch between the liver circular map I4 and the liver circular map I5 according to a switching instruction inputted via the input interface 14. Specifically, when the user operates the cursor 81 to click on the liver circular map I4, the processing circuit 11 switches the display object from the liver circular map I4 to the liver circular map I5. At this time, the processing circuit 11 may display the liver circular map I4 and the liver circular map I5 at the same position on the screen of the display device 13. Even by such a switching display, the user can grasp the portal vein blood flow rate and the hepatic artery blood flow rate of the entire liver at a glance. Moreover, the switching display makes it easy to grasp the portal vein blood flow rate and the hepatic artery blood flow rate at the same position.

[0081] (Display example 3) The processing circuit 11 according to the display example 3 displays a single circular liver map based on at least two feature data items, the portal vein blood flow rate, the arterial blood flow rate, the ratio, and the fat mass. The circular liver map according to the display example 3 is displayed in a mixed color of two colors corresponding to the two feature data items, respectively.

[0082] FIG. 24 is a diagram showing an example of a display screen IS3 according to a display example 3. As shown in FIG. 24, the processing circuit 11 displays a single liver circular map I8 relating to the portal vein blood flow rate and the hepatic artery blood flow rate on the display screen IS3. A color bar I6 relating to the portal vein blood flow rate and a color bar I7 relating to the hepatic artery blood flow rate are displayed near the liver circular map I8. The liver circular map I8 is assigned a color value according to the portal vein blood flow rate, a color value according to the hepatic artery blood flow rate, and a color value based on both color values ​​(hereinafter referred to as a mixed color value), and is displayed in a color according to the mixed color value. That is, the liver circular map I8 is displayed in a mixed color of the color according to the portal vein blood flow rate and the color according to the hepatic artery blood flow rate. The user can grasp both the portal vein blood flow rate and the hepatic artery blood flow rate just by observing the single liver circular map I8.

[0083] At this time, the processing circuit 11 may present the portal vein blood flow rate and the hepatic artery blood flow rate at the attention point on the liver circular map I8 to the user. For example, as shown in FIG. 25, when the attention point is designated by the cursor 81, the processing circuit 11 specifies the portal vein blood flow rate and the hepatic artery blood flow rate assigned to the designated attention point, and displays a window I9 including the numerical values ​​of the portal vein blood flow rate and the hepatic artery blood flow rate. For example, the window I9 displays portal vein: 80%, artery: 20%, etc. This allows the user to quantitatively and accurately grasp the portal vein blood flow rate and the hepatic artery blood flow rate at the attention point. Also, as shown in FIG. 25, when the attention point is designated by the cursor 81, the processing circuit 11 may specify the portal vein blood flow rate and the hepatic artery blood flow rate assigned to the designated attention point, and display a cursor I10 indicating a position on the color bar I6 that corresponds to the specified portal vein blood flow rate and a cursor I11 indicating a position on the color bar I7 that corresponds to the specified hepatic artery blood flow rate. This method also enables the user to quantitatively and accurately grasp the portal vein blood flow and hepatic artery blood flow at the point of interest.

[0084] As shown in FIG. 26, the processing circuitry 11 may display the liver circular map I8 and the axial slice image I12 of the subject's liver side by side. The axial slice image I12 may be generated by the processing circuitry 11 based on the time-series contrast volume data. For example, the processing circuitry 11 generates the axial slice image I12 by performing MPR processing on volume data of an arbitrary time phase among the time-series contrast volume data. As shown in FIG. 26, when a point of interest on the liver circular map I8 is specified by a cursor 81 as shown in FIG. 26, the processing circuitry 11 specifies a corresponding pixel on the axial slice image I12 that anatomically corresponds to the specified point of interest, and emphasizes the specified corresponding pixel. For example, the corresponding pixel may be emphasized by displaying a cursor I13 pointing to the corresponding pixel on the axial slice image I12. Note that the emphasis method is not limited to this, and for example, the corresponding pixel may be colored in a specific color, a mark may be added to the corresponding pixel, or a visual effect such as blinking may be added.

[0085] Conversely, when a point of interest on the axial slice image I12 is designated by the cursor 81, a corresponding pixel on the liver circular map I8 that anatomically corresponds to the designated point of interest may be specified, and the specified corresponding pixel may be emphasized. Furthermore, the images displayed side by side on the liver circular map I8 are not limited to axial slice images, and may be any CT images generated by applying three-dimensional image processing to time-series contrast volume data, such as sagittal slice images, coronal slice images, oblique slice images, and volume rendering images.

[0086] (Display example 4) The processing circuitry 11 according to the display example 4 superimposes various anatomical information of the subject obtained based on the time-series contrast volume data onto the circular liver map. Examples of the anatomical information to be superimposed include the positions of blood vessels and tumors contained in the liver. The circular liver map according to the display example 4 may be a projection of any of the feature quantities of the portal vein blood flow, the hepatic artery blood flow, and the portal vein / hepatic artery blood flow ratio.

[0087] As shown in FIG. 27, the processing circuit 11 may display the vascular position I15 superimposed on the liver circular map I14. The method of superimposing the vascular position I15 is performed, for example, as follows. First, the processing circuit 11 extracts a vascular region of interest from the time-series contrast volume data by image processing or the like. The vascular region of interest may be the entirety or a part of the portal vein region and the hepatic artery region. Next, the processing circuit 11 projects the extracted vascular region onto the liver circular map I14 based on the correspondence (coordinate transformation formula) between pixels of the liver segment and the liver circular map. More specifically, the processing circuit 11 sets a plurality of sample points that are discretely arranged on the center line of the extracted vascular region, and applies a coordinate transformation formula to the plurality of sample points to project them onto the liver circular map I14. At this time, the processing circuit 11 identifies the liver segment to which the sample point to be projected belongs, and applies the coordinate transformation formula corresponding to the identified liver segment to the sample point. Then, the processing circuitry 11 forms a blood vessel position I15 on the liver circular map I14 by connecting the multiple sample points projected on the liver circular map I14 with straight lines or the like. The processing circuitry 11 displays the blood vessel position I15 in a specific color such as blue or red by superimposing it on the liver circular map I14. The processing circuitry 11 may also calculate a liver blood flow parameter value for each pixel of the blood vessel position I15 and display each pixel in a color corresponding to the blood flow parameter value.

[0088] When the liver circular map I14 is a liver circular map related to portal vein blood flow, the portal vein position may be superimposed on the liver circular map I14, or a combination of the portal vein position and the hepatic artery position may be superimposed on the liver circular map I14, or the hepatic artery position may be superimposed on the liver circular map I14. Similarly, when the liver circular map I14 is a liver circular map related to hepatic artery blood flow or a portal vein / hepatic artery blood flow ratio, the portal vein position may be superimposed on the liver circular map I14, or a combination of the portal vein position and the hepatic artery position may be superimposed on the liver circular map I14. The processing circuit 11 may cyclically switch the blood vessel positions to be superimposed on the liver circular map I14 in the order of the portal vein position, the combination of the portal vein position and the hepatic artery position, the hepatic artery position, etc., every time a switching instruction is given by the user via the input interface 14.

[0089] In this way, by superimposing the blood vessel positions on the circular liver map, it becomes possible to easily and comprehensively grasp the positional relationship between the hepatic blood flow parameters distributed throughout the liver and the hepatic blood vessels.

[0090] As shown in FIG. 28, the processing circuit 11 may project the tumor position I16 onto the liver circular map I14 in addition to the blood vessel position I15. The tumor position I16 can be extracted and projected in the same manner as the blood vessel position I15. For example, the processing circuit 11 first extracts a tumor region of interest from the time-series contrast volume data by image processing or the like. Next, the processing circuit 11 projects the extracted tumor region onto the liver circular map I14 based on the correspondence (coordinate transformation formula) between the pixels of the liver segment and the liver circular map. More specifically, the processing circuit 11 sets a plurality of sample points that are discretely arranged on the contour of the extracted tumor region, and applies a coordinate transformation formula to the plurality of sample points to project onto the liver circular map I4. At this time, the processing circuit 11 identifies the liver segment to which the tumor region to be projected belongs, and applies the coordinate transformation formula corresponding to the identified liver segment to each sample point on the tumor region. Then, the processing circuitry 11 forms a tumor position I16 on the liver circular map I14 by connecting the multiple sample points projected on the liver circular map I14 with straight lines or the like. The tumor position I16 may be superimposed on the liver circular map I14 and displayed in a specific color such as red or black, or may be displayed in a color corresponding to the liver blood flow parameter value or CT value for each pixel.

[0091] In this way, by superimposing the positions of blood vessels and the tumor on the circular map of the liver, the positional relationship between the tumor and blood vessels, and the positional relationship between the liver and the tumor can be easily understood.

[0092] The processing circuitry 11 may project a tumor region extracted from volume data collected by another nuclear medicine diagnostic device such as a PET device or a SPECT device onto the liver circular map I14 as the tumor position I16. In this case, the processing circuitry 11 may align the volume data collected by the nuclear medicine diagnostic device with the time-series contrast volume data collected by the X-ray computed tomography device, and then apply a coordinate transformation formula corresponding to the liver segment to which the tumor region belongs to the tumor region and project it. This allows the processing circuitry 11 to display the tumor region in a color derived from the nuclear medicine diagnostic device according to the degree of accumulation of the radiopharmaceutical.

[0093] In addition, the processing circuit 11 may display the blood vessel position of the blood vessel connected to the tumor in a color different from the blood vessel position of the blood vessel not connected to the tumor in order to facilitate understanding of the blood vessel connected to the tumor. Furthermore, the processing circuit 11 may superimpose only the tumor position without superimposing both the tumor position and the blood vessel position. In this case, the processing circuit 11 may cyclically switch the superimposition target in the order of the blood vessel position, the combination of the blood vessel position and the tumor position, and the tumor position, every time a switching instruction is given by the user via the input interface 14. Furthermore, the processing circuit 11 may superimpose any lesion position occurring in the liver, not limited to the tumor position, on the liver circular map.

[0094] (Example 5) The processing circuitry 11 according to the display example 5 displays a plurality of liver circular maps relating to a plurality of examination time points in chronological order. At this time, the processing circuitry 11 displays the liver circular map of the current examination and the liver circular map of the previous examination in chronological order, or switches between the liver circular map of the current examination and the liver circular map of the previous examination according to a user instruction. Hereinafter, an example will be described in which progress observation is performed while performing radiation therapy, anticancer drug therapy, or gene therapy for liver cancer.

[0095] As shown in FIG. 29, the processing circuit 11 displays a plurality of liver circular maps related to a plurality of examination time points in a chronological order on the display screen IS4. A liver circular map I17 related to an examination one year ago, a liver circular map I18 related to an examination six months ago, and a liver circular map I19 related to today's examination are displayed side by side. A tumor position I20 and a tumor position I21 are superimposed on the liver circular map I17 related to an examination one year ago and the liver circular map I18 related to an examination six months ago, respectively. As the tumor shrinks over time, the tumor positions I20 and I21 shrink. In addition, the tumor has disappeared in today's examination, and therefore there is no tumor area in the liver circular map I17.

[0096] By displaying multiple circular liver maps for multiple examination points in time, the changes in blood flow throughout the liver as the tumor shrinks can be easily and comprehensively understood, making it possible to visually grasp the process by which the blood flow in the tumor and its surrounding areas returns to portal dominance.

[0097] In addition, the multiple liver circular maps for multiple examination time points are not limited to being displayed side by side. For example, the processing circuitry 11 may display the multiple liver circular maps for multiple examination time points one by one while switching them in order. In this case, the processing circuitry 11 may switch and display the liver circular maps to be displayed in chronological order every time a switching instruction is given by the user via the input interface 14.

[0098] (Example 6) The processing circuit 11 according to the display example 6 displays a single circular liver map based on at least two feature data items, that is, the portal vein blood flow rate, the arterial blood flow rate, the ratio, and the fat mass. The circular liver map according to the display example 6 displays the above two feature data items in different sections within the single circular liver map.

[0099] FIG. 30 is a diagram showing an example of a display screen according to the display example 6. As shown in FIG. 30, the processing circuitry 11 displays a liver circular map I22 on the display screen IS5, in which the portal vein blood flow rate and the hepatic artery blood flow rate are separated in terms of location and projected onto one circular template. Each display section S1-S7 of the liver circular map I22 is radially divided into a subsection I23 on the outer periphery side and a subsection I24 on the inner periphery side. For example, the subsection I23 is assigned to the portal vein blood flow rate, and the subsection I24 is assigned to the hepatic artery blood flow rate. The processing circuitry 11 performs pixel-to-pixel correspondence with the liver segment for each of the subsections I23 and I24 individually. Based on the correspondence, the processing circuitry 11 projects the portal vein blood flow rate onto the subsection I23, and projects the hepatic artery blood flow rate onto the subsection I24. Each pixel in sub-zone I23 is displayed in a color according to color bar I6 relating to portal vein blood flow, and each pixel in sub-zone I24 is displayed in a color according to color bar I7 relating to hepatic artery blood flow.

[0100] By displaying the liver circular map I22, the user can check the portal vein blood flow and the hepatic artery blood flow individually on one liver circular map.

[0101] The hepatic artery blood flow rate may be assigned to the sub-section I23 on the outer circumference side, and the hepatic artery blood flow rate may be assigned to the sub-section I24 on the inner circumference side. The feature values ​​assigned to the sub-sections I23 and I24 are not limited to the portal vein blood flow rate and the hepatic artery blood flow rate, but may be the portal vein blood flow rate and the portal vein / hepatic artery blood flow ratio, or the hepatic artery blood flow rate and the portal vein / hepatic artery blood flow ratio. Each display section is not limited to being divided into two, but may be divided into three. In this case, the portal vein blood flow rate may be projected onto the first sub-section, the hepatic artery blood flow rate may be projected onto the second sub-section, and the portal vein / hepatic artery blood flow ratio may be projected onto the third sub-section. The display section is not limited to being divided in the radial direction, but may be divided in any direction, such as the circumferential direction or the diagonal direction. The display section is not limited to being divided in one direction, but may be divided in any arbitrary manner, such as a lattice pattern.

[0102] (Example 7) The processing circuit 11 according to the seventh display example displays a circular liver map in which a display section corresponding to a resected liver segment among a plurality of liver segments of the liver is highlighted. In the following description, it is assumed, as an example, that the liver segment S7 has been resected in order to remove a tumor present in the liver segment S7.

[0103] As shown in Fig. 31, in the pre-resection circular map I26 of the liver, a tumor position I27 is superimposed on a display section S7 corresponding to the liver segment S7. When the liver segment S7 is resected, the processing circuitry 11 displays a circular map I28 of the liver in which the display section S7 corresponding to the resected liver segment S7 is missing. Any feature amount such as portal vein blood flow, hepatic artery blood flow, or portal vein / hepatic artery blood flow ratio may be projected on the circular map I8 of the liver. The fact that the display section S7 is missing may be manually input via the input interface 14, or may be recognized by image processing.

[0104] In the case of manual input, the user inputs information that the liver segment S7 has been resected via the input interface 14. When the information is input, the processing circuitry 11 deletes the display section S7 from the pre-resection template and projects the feature data onto the post-resection template, thereby generating a post-resection circular liver map I28.

[0105] When recognition is performed by image processing, the processing circuitry 11 extracts the liver region from the time-series contrast volume data of the subject after resection, and divides the liver region into liver segments S1-S8. At this time, the processing circuitry 11 recognizes that the liver segment S7 has been resected because the liver region does not include the liver segment S7. Thereafter, the processing circuitry 11 deletes the display section S7 from the template before resection, and projects the feature data onto the template after deletion. This generates a circular liver map I28 after resection.

[0106] As shown in FIG. 31, a circular liver map I28 is displayed in which a display section corresponding to the resected liver segment is missing, thereby enabling the user to recognize the resected liver segment in the circular liver map I28.

[0107] As shown in FIG. 32, the processing circuit 11 may display another post-resection liver circular map I29. The liver circular map I29 does not lack a display section S7 corresponding to the resected liver segment S7, and includes all display sections S1-S8. The display sections S1-S6, S8 corresponding to the non-resected liver segments S1-S6, S8 of the liver circular map I29 are displayed in colors corresponding to the assigned feature values, and the display section S7 corresponding to the resected liver segment S7 is displayed, for example, colorless, since no feature value is assigned to it. Since the display section S7 corresponding to the resected liver segment S7 is not displayed in color, the user can recognize the resected liver segment S7 in the liver circular map I28.

[0108] As shown in Fig. 33, the processing circuit 11 may display another post-resection liver circular map I30. In the liver circular map I30, a display section S7 corresponding to the resected liver segment S7 is drawn in a dotted line. Since no feature value is assigned to the display section S7, it is displayed in no color. In this way, since the display section S7 corresponding to the resected liver segment S7 is displayed in a dotted line, the user can recognize the resected liver segment S7 in the liver circular map I28.

[0109] In addition, the display area corresponding to the resected liver segment is not limited to being drawn by a dotted line, and may be displayed in any manner as long as it is visually distinguishable from the display area corresponding to the non-resected liver segment. For example, the processing circuit 11 may display the display area corresponding to the resected liver segment in a color different from that of the display area corresponding to the non-resected liver segment.

[0110] As shown in FIG. 34, the processing circuitry 11 may display another post-resection liver circular map I31. The liver circular map I31 is formed in a circular shape by display sections S1-S6, S8 corresponding to the remaining liver segments S1-S6, S8 excluding the liver segment S7. For example, the processing circuitry 11 determines the arrangement of the display sections S2, S3, and S6 in the outer region based on the sizes of the remaining liver segments S2, S3, and S6 included in the outer region to which the resected liver segment S7 belonged. This generates a post-resection template. The liver segments S2, S3, and S6 can be obtained by dividing the liver region included in the post-resection time-series contrast volume data into liver segments. The processing circuitry 11 can then generate the liver circular map I31 by projecting feature data based on the post-resection time-series contrast volume data onto the post-resection template.

[0111] The processing circuitry 11 may generate the liver circular map I31 by newly performing the process shown in FIG. 15 on the time-series contrast volume data after the resection. That is, the processing circuitry 11 extracts the liver region, the portal vein region, and the hepatic artery region from the time-series contrast volume data after the resection, and divides the liver region into a plurality of liver segments S1-S6, S8. Next, the processing circuitry 11 calculates the distance and direction between each of the liver segments S1-S6, S8 and a reference position, and calculates the size of each of the liver segments S1-S6, S8. Next, the processing circuitry 11 determines the arrangement of the display sections S1-S6, S8 in the template based on the calculated distance, direction, and size, and reconstructs the template. Then, the processing circuitry 11 projects the feature data onto the reconstructed template to generate the liver circular map I31.

[0112] As shown in Figure 34, in the liver circular map I31, the remaining display sections S1-S6, S8 can have a relatively large area, making it possible to grasp in detail the spatial distribution of blood flow parameters in the remaining liver sections S1-S6, S8.

[0113] (Example 8) The resected liver regenerates. The processing circuit 11 according to the display example 8 displays the degree of liver regeneration together with the circular map of the liver. In the following description, it is assumed that the liver segment S7 has been resected and is in the process of regeneration.

[0114] FIG. 35 is a diagram showing an example of a display screen IS6 according to a display example 8. As shown in FIG. 35, the processing circuit 11 displays a liver circular map I32 related to the regenerating liver and a window I33 for the regeneration ratio side by side on the display screen IS6. The liver circular map I32 is generated based on time-series contrast volume data related to a patient whose liver is being regenerated. Specifically, the processing circuit 11 extracts a liver region from the time-series contrast volume data related to the patient whose liver is being regenerated, and divides the liver region into a plurality of liver segments S1-S8. The regenerating liver partial region is also divided as a liver segment S7. Next, the processing circuit 11 calculates the distance and direction between each liver segment S1-S8 and a reference position. Next, the processing circuit 11 determines the arrangement of the display segments S1-S8 in the template based on the calculated distance and direction, and reconstructs the template. The area and arrangement of the display segments may be determined based on the liver segments S1-S8 before resection in order to improve the visibility of the display segments corresponding to the regenerating liver segments. The area of ​​the display section may be determined uniformly or arbitrarily in advance, as in the first and second generation methods. Then, the processing circuitry 11 projects the feature data onto the template to generate a liver circular map I32.

[0115] As shown in Fig. 35, in the display section S7 of the liver circular map I32, only pixels corresponding to the part where liver tissue exists and blood flow due to regeneration are assigned feature values ​​and displayed in a color according to the feature value. Pixels corresponding to the part where liver tissue does not exist and blood flow is not yet regenerated are not assigned feature values ​​and are therefore displayed colorless. Note that the pixels may not be colorless and may be displayed in a color (e.g., gray) associated with the fact that the liver has not yet regenerated. This makes it possible to grasp the spatial distribution of blood flow parameters of the liver segment S7 in the process of regeneration.

[0116] As shown in FIG. 35, the regeneration ratio is displayed in the window I33. The regeneration ratio is defined as the ratio of the current volume to the volume before the resection. The processing circuit 11 calculates the volume of the liver segment S7 before the resection and the current volume of the liver segment S7, calculates the ratio of the volume of the liver segment S7 before the resection to the current volume of the liver segment S7, and displays the ratio as the regeneration ratio. For example, as shown in FIG. 35, when the regeneration ratio of the liver segment S7 is 25%, "S7" and "regeneration ratio: 25%" are displayed. By displaying the window I33, the user can know the regeneration ratio of the resected liver segment.

[0117] (Variation 1) In the above various embodiments, the liver unfolded map is a circular liver map in which the display sections S1-S8 in the shape of an annulus or sector shape representing the liver segments S1-S8 are arranged on a two-dimensional circular template with the reference position such as the hepatic portal area as the center point. However, the liver unfolded map of the present embodiment is not limited to this. For example, the liver unfolded map may be a map in which the display sections S1-S8 in the shape of a rectangle representing the liver segments S1-S8 are arranged on a two-dimensional rectangular template with the reference position such as the hepatic portal area as the center point. Also, as shown in FIG. 36, the liver unfolded map I34 may be a map in which the display sections S1-S8 in the shape of a mimicking the liver segments S1-S8 are arranged on a two-dimensional plane. The reference position P0 is drawn on the liver unfolded map I34, and a figure such as an arrow representing the blood flow path from the hepatic portal area, which is the reference position P0, to each display section S1-S8 is drawn. Since the feature amount data is also projected on the display sections S1-S8 in the liver unfolded map I34, each pixel of the display sections S1-S8 is displayed in a color according to the feature amount.

[0118] (Variation 2) In the above various embodiments, the feature amount projected on the display section is a blood flow parameter calculated by a CT perfusion test. However, this embodiment is not limited to this. As described above, the feature amount may be a fat amount. The fat amount can be calculated based on a CT value. The processing circuit 11 calculates the fat amount for each pixel of the liver section based on the CT value, and assigns the fat amount to the corresponding pixel of the display section. This generates a liver unfolded map related to the fat amount. The processing circuit 11 holds a color table in which the fat amount and the color value are associated. The processing circuit 11 can display the liver unfolded map in a color corresponding to the fat amount by referring to the color table. Note that the feature amount is not limited to a blood flow parameter or a fat amount, and may be a CT value or another analysis parameter.

[0119] (Variation 3) In the various embodiments described above, the medical image processing apparatus 1 is a computer separate from the medical image diagnostic apparatus 2. However, the present embodiment is not limited to this. The medical image processing apparatus 1 may be a computer incorporated in the medical image diagnostic apparatus 2.

[0120] According to at least one of the embodiments described above, feature quantities such as the arterial / portal blood flow ratio of the entire liver can be grasped in a short period of time.

[0121] The term "processor" used in the above description means a circuit such as a CPU, a GPU, 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)). The processor realizes its function by reading and executing a program stored in a memory circuit. Instead of storing a program in a memory circuit, the processor may be configured to directly incorporate the program in the circuit. In this case, the processor realizes its function by reading and executing a program incorporated in the circuit. Instead of executing a program, a function corresponding to the program may be realized by a combination of logic circuits. Each processor in this embodiment is not limited to being configured as a single circuit for each processor, but may be configured as one processor by combining multiple independent circuits to realize its function. Furthermore, the multiple components in FIG. 1 and FIG. 2 may be integrated into one processor to realize its function.

[0122] Although some embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations of embodiments can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents as described in the claims, as well as in the scope and spirit of the invention. [Explanation of symbols]

[0123] 1 Medical image processing device 2 Medical imaging diagnostic equipment 3 Medical image storage device 11 Processing circuit 12 Communication Interface 13 Display equipment 14 Input Interface 15 Storage device 111 Image Processing Functions 112 Feature acquisition function 113 Map generation function 114 Display control function

Claims

1. a division unit that divides a liver region included in the liver volume data into a plurality of liver segments based on the vascular course of the portal vein region and / or the hepatic artery region; an acquisition unit that acquires feature amount data related to feature amounts of the liver based on the volume data; a unit for generating a map by projecting the feature amount data onto a two-dimensional development having a plurality of display sections respectively corresponding to the plurality of liver segments, the unit generating a development in which the plurality of display sections respectively corresponding to the plurality of liver segments are arranged with a reference position of the portal vein region as a center point, and generating the map by projecting the feature amount data onto the development; A display control unit that displays the map; A medical image processing device comprising:

2. The medical image processing apparatus according to claim 1 , wherein the generating unit uses a hepatic portal portion of the liver as the reference position.

3. The medical image processing apparatus according to claim 1 , wherein the generating unit determines an arrangement of the plurality of display sections in the developed view based on a distance and / or a direction between the reference position and the plurality of liver segments in the volume data.

4. The medical image processing apparatus according to claim 1 , wherein the generating unit determines a size of each of the display sections in the developed view based on a size of each of the liver segments in the volume data.

5. 5 . The medical image processing apparatus according to claim 1 , wherein the feature data includes at least one of portal vein blood flow, arterial blood flow, a ratio between portal vein blood flow and arterial blood flow, and fat mass.

6. 6. The medical image processing device according to claim 5, wherein the display control unit displays two maps based on at least two of the feature data, portal vein blood flow, arterial blood flow, a ratio of portal vein blood flow to arterial blood flow, and fat mass, side by side.

7. The medical image processing apparatus according to claim 5 , wherein the display control unit displays a single map based on at least two of the feature amount data of the portal vein blood flow rate, the arterial blood flow rate, the ratio, and the fat mass.

8. The medical image processing apparatus according to claim 1 , wherein the display control unit displays the map on which a tumor position in the liver is superimposed.

9. The medical image processing apparatus according to claim 1 , wherein the display control unit displays the map on which positions of blood vessels in the liver are superimposed.

10. The medical image processing apparatus according to claim 1 , wherein the display control unit displays the map in which a display section corresponding to a resected liver segment among the plurality of liver segments is highlighted.

11. The medical image processing device according to claim 1 , wherein the display control unit displays the map of the current examination and the map of the past examination in chronological order, or switches between the map of the current examination and the map of the past examination in accordance with a user instruction.

12. The medical image processing device according to claim 1 , wherein the display control unit displays the map with color values ​​corresponding to the feature values, and displays a color bar next to the map indicating the correspondence between the feature values ​​and the color values.

13. The medical image processing device according to claim 12 , wherein the display control unit, when a point of interest on the map is specified, displays a feature amount of the point of interest as a numerical value, and / or displays an arrow indicating a position on the color bar corresponding to the feature amount of the point of interest.

14. 13. The medical image processing device according to claim 12, wherein the display control unit displays the map and a display image based on the volume data, and when a first point of interest in the map is specified, emphasizes a position in the display image corresponding to the first point of interest, and when a second point of interest in the display image is specified, emphasizes a position in the map corresponding to the second point of interest.

15. 2. The medical image processing device according to claim 1, wherein the generation unit determines a distance and / or a direction between the reference position and each of the plurality of liver segments, and generates the developed view in which the plurality of display sections are allocated in a circular shape according to the distance and / or direction with the reference position as a center.

16. 16. The medical image processing device according to claim 15, wherein the generation unit divides the plurality of liver segments into an inner liver segment and an outer liver segment based on the distance and a threshold value, and arranges a display segment corresponding to the inner liver segment among the plurality of display segments in an inner region of the two regions obtained by radially dividing the developed view, and arranges a display segment corresponding to the outer liver segment among the plurality of display segments in an outer region.

17. 17. The medical image processing device of claim 15, wherein the generation unit unfolds each of the plurality of liver segments along a cross section corresponding to the running direction of the portal vein region connected to the liver segment, corresponds each first pixel of the cross section in the unfolded liver segment to each second pixel of a display section corresponding to the liver segment, and assigns a projection value along a projection line perpendicular to the cross section, passing through the first pixel, and penetrating the unfolded liver segment to the second pixel of the display section.

18. an imaging unit that performs medical imaging on the liver of a subject and collects raw data; a reconstruction unit for reconstructing volume data based on the raw data; a division unit that divides a liver region included in the volume data into a plurality of liver segments based on a blood vessel course of a portal vein region and / or a hepatic artery region; an acquisition unit that acquires feature amount data related to feature amounts of the liver based on the volume data; a unit for generating a map by projecting the feature amount data onto a two-dimensional development having a plurality of display sections corresponding to a plurality of hepatic segments determined based on the vascular course of the liver, the unit generating a development in which the plurality of display sections corresponding to the plurality of hepatic segments are arranged with a reference position of the portal vein region as a center point, and generating the map by projecting the feature amount data onto the development; A display control unit that displays the map; A medical image diagnostic apparatus comprising:

Images