Medical image processing apparatus

Abstract

To enable at least one of facilitating grasping of a comparison result of a plurality of medical images captured in different postures, and reducing a capacity required to store CT image data.SOLUTION: A medical image processing apparatus according to an embodiment comprises a storage unit, an acquisition unit, an extraction unit, a data writing unit, and a restoration unit. The acquisition unit acquires first medical image data in which a subject in a first posture state is scanned, and second medical image data in which the subject in a second posture state different from the first posture state is scanned. The extraction unit extracts difference data between the first medical image data and the second medical image data. The data writing unit stores the difference data and the second medical image data in the storage unit. The restoration unit restores the first medical image data based on the difference data and the stored second medical image data.SELECTED DRAWING: Figure 15

Description

[Technical field]

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

[0002] Conventionally, in imaging using a medical imaging diagnostic device such as an X-ray CT (Computed Tomography) device, there are known a technique for imaging a subject lying on a bed and a technique for imaging a subject in a standing or sitting position. The effect of gravity on a subject is different between a lying position and a standing or sitting position. For this reason, a doctor or technician may generally refer to the results of comparing multiple medical images taken in different positions to determine the severity of a lesion.

[0003] However, when visually comparing multiple medical images taken in different postures, it can be difficult to make a highly accurate distinction because the accuracy of the distinction depends on the experience or ability of the doctor or technician. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent Application Publication No. 2013 / 0110250 Summary of the Invention [Problem to be solved by the invention]

[0005] One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to make it possible to easily grasp the results of comparing multiple medical images taken in different postures and to reduce the storage capacity of CT image data. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problems. 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]

[0006] A medical image processing apparatus according to an embodiment includes a storage unit, an acquisition unit, an extraction unit, a data writing unit, and a restoration unit. The acquisition unit acquires first medical image data obtained by scanning a subject in a first posture state, and second medical image data obtained by scanning a subject in a second posture state different from the first posture state. The extraction unit extracts difference data between the first medical image data and the second medical image data. The data writing unit stores the difference data and the second medical image data in the storage unit. The restoration unit restores the first medical image data based on the difference data and the stored second medical image data. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a block diagram showing an example of an X-ray CT apparatus according to the first embodiment. [Diagram 2] FIG. 2 is a diagram showing an example of a subject in a standing position. [Diagram 3] FIG. 3 is a diagram showing an example of a sitting position of a subject. [Figure 4] FIG. 4 is a diagram showing an example of the appearance of the gantry device during scanning in a standing or sitting position according to the first embodiment. [Diagram 5] FIG. 5 is a diagram showing an example of a subject in a supine position. [Figure 6] FIG. 6 is a diagram showing an example of the external appearance of the gantry device during scanning in the supine position according to the first embodiment. [Figure 7] FIG. 7 is a diagram showing an example of supine position image data according to the first embodiment. [Figure 8] FIG. 8 is a diagram illustrating an example of standing position image data according to the first embodiment. [Figure 9] FIG. 9 is a diagram illustrating an example of the conversion process according to the first embodiment. [Figure 10] FIG. 10 is a diagram showing an example of differential region data according to the first embodiment. [Figure 11]FIG. 11 is a diagram showing an example of a comparison screen according to the first embodiment. [Figure 12] FIG. 12 is a diagram illustrating an example of a processing flow according to the first embodiment. [Figure 13] FIG. 13 is a diagram showing an example of the position of the second imaging section according to the second embodiment. [Figure 14] FIG. 14 is a diagram showing an example of an axial image according to the second embodiment. [Figure 15] FIG. 15 is a block diagram showing an example of an X-ray CT apparatus according to the third embodiment. [Figure 16] FIG. 16 is a diagram illustrating an example of data to be saved according to the third embodiment. [Figure 17] FIG. 17 is a diagram showing an example of a display of numerical information according to the second modification. [Figure 18] FIG. 18 is a diagram showing another example of the display of numerical information according to the second modification. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, embodiments of a medical image diagnostic apparatus and a medical image processing apparatus will be described in detail with reference to the drawings.

[0009] (First embodiment) 1 is a block diagram showing an example of an X-ray CT (Computed Tomography) apparatus 1 according to the first embodiment. The X-ray CT apparatus 1 is an example of a medical image diagnostic apparatus and a medical image processing apparatus in this embodiment.

[0010] The X-ray CT device 1 of this embodiment can accommodate a plurality of different postures of the subject. For example, the X-ray CT device 1 of this embodiment can scan the subject in a lying, standing, and sitting position. The lying position is an example of a first posture in this embodiment. The standing and sitting positions are examples of a second posture in this embodiment. It is not essential to scan in both the standing and sitting positions. For example, the X-ray CT device 1 may accommodate either the standing or sitting position in addition to the lying position.

[0011] As shown in FIG. 1, the X-ray CT apparatus 1 includes a gantry device 10 and a console device 40. Although not shown in FIG. 1, the X-ray CT apparatus 1 further includes a bed device on which a subject is placed. The bed device may be included in the configuration of the X-ray CT apparatus 1, or may be a configuration outside the X-ray CT apparatus 1. The X-ray CT apparatus 1 may also include a patient support mechanism that supports a patient during upright imaging. The patient support mechanism corresponds to the top plate of the bed device in the supine CT. The patient support mechanism may be a platform that can be fixed to the floor surface, or may be movable while supporting the patient. The patient support mechanism may also serve as the bed device. The X-ray CT apparatus 1 may not include a patient support mechanism for upright imaging.

[0012] The gantry device 10 includes a gantry body 11, a support section 12, and a control device 17. Note that the configuration of the X-ray CT device 1 shown in Fig. 1 is merely an example, and is not limited to the configuration shown in the figure.

[0013] In this embodiment, the longitudinal direction of the rotation axis C0 of the rotating frame 130 in a non-tilted state is defined as the Z-axis direction, the direction perpendicular to the Z-axis direction and from the rotation center toward the support unit 12 supporting the rotating frame 130 is defined as the X-axis, and the direction perpendicular to the Z-axis and the X-axis is defined as the Y-axis. In this embodiment, when the gantry device 10 is in a non-tilted state, the longitudinal direction of the rotation axis C0 is perpendicular to the floor surface as shown in Fig. 1. The definitions of the X-axis, Y-axis, and Z-axis in Fig. 1 are merely examples, and any three axial directions perpendicular to each other can be defined as the X-axis, Y-axis, and Z-axis.

[0014] The gantry body 11 has an opening 13 for accommodating an imaging region of a subject. The gantry body 11 also has an X-ray tube 14, an X-ray detector 15, an X-ray high voltage device 16, a control device 17, a DAS (Data Acquisition System) 18, and a rotating frame 130. The gantry body 11 is also called an imaging device or an imaging unit.

[0015] The X-ray tube 14 is a vacuum tube that generates X-rays by irradiating thermoelectrons from a cathode (filament) to an anode (target) by application of high voltage from the X-ray high voltage device 16. For example, the X-ray tube 14 may be a rotating anode type X-ray tube that generates X-rays by irradiating a rotating anode with thermoelectrons. Note that a wedge (also called a wedge filter or bowtie filter) for adjusting the amount of X-rays irradiated from the X-ray tube 14 and a collimator (also called an X-ray aperture) for narrowing the irradiation range of the X-rays that have passed through the wedge are provided near the X-ray tube 14.

[0016] The X-ray detector 15 detects X-rays irradiated from the X-ray tube 14 and passing through the subject P, and outputs an electrical signal corresponding to the X-ray dose to the DAS 18. The X-ray detector 15 has, for example, a plurality of X-ray detection element rows in which a plurality of X-ray detection elements are arranged in the channel direction along one arc centered on the focal point of the X-ray tube 14. The X-ray detector 15 has a structure in which, for example, a plurality of X-ray detection element rows in which a plurality of X-ray detection elements are arranged in the channel direction are arranged in the slice direction (row direction).

[0017] The X-ray detector 15 is an indirect conversion type detector having, for example, a grid, a scintillator array, and an optical sensor array. The scintillator array has a plurality of scintillators, and the scintillator has a scintillator crystal that outputs light with a photon amount corresponding to the amount of incident X-rays. The grid is disposed on the X-ray incident side of the scintillator array, and has an X-ray shielding plate having a function of absorbing scattered X-rays. The grid may also be called a collimator (one-dimensional collimator or two-dimensional collimator). The optical sensor array has a function of converting light from the scintillator into an electrical signal corresponding to the amount of light, and has an optical sensor such as a photomultiplier tube (PMT). The X-ray detector 15 may be a direct conversion type detector having a semiconductor element that converts incident X-rays into an electrical signal.

[0018] The X-ray tube 14 and the X-ray detector 15 are provided on a rotating frame 130. The rotating frame 130 is an annular frame that supports the X-ray tube 14 and the X-ray detector 15 facing each other, and rotates the X-ray tube 14 and the X-ray detector 15 around a rotation axis C0. The rotating frame 130 further supports the X-ray high voltage device 16 and the DAS 18 in addition to the X-ray tube 14 and the X-ray detector 15. The rotating frame 130 is rotatably supported by a non-rotating part (e.g., a fixed frame; not shown in FIG. 1) of the gantry device 10. The rotating frame 130 is rotated by a rotating mechanism. The rotating mechanism includes, for example, a motor that generates a rotational driving force and a bearing that transmits the rotational driving force to the rotating frame 130 to rotate it. The motor is provided in the non-rotating part, for example, and the bearing is physically connected to the rotating frame 130 and the motor, and the rotating frame 130 rotates according to the rotational force of the motor.

[0019] The rotating frame 130 and the non-rotating part are provided with a non-contact or contact communication circuit, which allows communication between the unit supported by the rotating frame 130 and the non-rotating part or an external device of the gantry 10. For example, when optical communication is used as the non-contact communication method, the detection data generated by the DAS 18 is transmitted by optical communication from a transmitter having a light-emitting diode (LED) provided on the rotating frame 130 to a receiver having a photodiode provided on the non-rotating part of the gantry 10, and is further transferred from the non-rotating part to the console device 40 by the transmitter. As the communication method, in addition to the above, a non-contact data transmission method such as a capacitive coupling method or an electromagnetic wave method, or a contact data transmission method using a slip ring and an electrode brush may be used. The rotating frame 130 is an example of a rotating part.

[0020] The X-ray high voltage device 16 has electric circuits such as a transformer and a rectifier, and includes a high voltage generator having a function of generating a high voltage to be applied to the X-ray tube 14, and an X-ray control device that controls the output voltage according to the X-rays irradiated by the X-ray tube 14. The high voltage generator may be of a transformer type or an inverter type. The X-ray high voltage device 16 may be provided on the rotating frame 130, or may be provided on the fixed frame side of the gantry device 10. The fixed frame is a frame that rotatably supports the rotating frame 130.

[0021] The DAS 18 has an amplifier that performs an amplification process on the electric signals output from each X-ray detection element of the X-ray detector 15, and an A / D converter that converts the electric signals into digital signals, and generates detection data. The detection data generated by the DAS 18 is transferred to the console device 40. The DAS 18 is also an example of a data acquisition unit.

[0022] The support part 12 is a structure (pillar) that supports the gantry body 11 so as to be movable and tiltable, and is configured with a column-shaped frame for supporting the gantry body 11. The support part 12 is also called a gantry support part or a pillar. Although FIG. 1 shows a case in which the X-ray CT device 1 includes one support part 12, the X-ray CT device 1 may include two or more support parts 12.

[0023] The control device 17 has a processing circuit having a CPU (Central Processing Unit) and the like, and a driving mechanism such as a motor and an actuator for moving and tilting the gantry body 11. The control device 17 has a function of receiving input signals from input devices (such as an input interface 43 described later) attached to the gantry device 10 and the console device 40 and controlling the operation of the gantry device 10. For example, the control device 17 receives input signals and controls the rotation of the rotating frame 130, and controls the movement (up and down movement) and tilt of the gantry body 11. The movement and tilt control of the gantry body 11 is executed according to information (movement distance, tilt angle, etc.) input by an input interface attached to the gantry device 10.

[0024] The control device 17 may be provided in the gantry device 10 or in the console device 40. When the control device 17 is provided in the gantry device 10, the control device 17 may be provided in the gantry body 11, the support unit 12, or in a separate housing different from the gantry body 11 and the support unit 12.

[0025] Here, the orientation of the gantry device 10 when the X-ray CT apparatus 1 scans the subject in a standing or sitting position will be described. Fig. 2 is a diagram showing an example of the standing position of the subject P. Fig. 3 is a diagram showing an example of the sitting position of the subject P. The standing position is a state in which the subject P stands on the floor surface or on a patient support mechanism on which the X-ray CT apparatus 1 is installed. The sitting position is a state in which the subject P sits in a wheelchair or chair (hereinafter referred to as wheelchair or the like). In the standing and sitting positions, the subject P is subjected to weight load in the direction of gravity.

[0026] 4 is a diagram showing an example of the appearance of the gantry 10 during scanning in a standing or sitting position according to the first embodiment. When the X-ray CT apparatus 1 scans the subject P in a standing or sitting position, the opening 13 of the gantry 10 faces upward and downward as shown in FIG. 4. The subject P enters the opening 13 from the lower side of the gantry 10 in a standing or sitting position. The gantry 10 may be lowered onto the floor surface with respect to the subject P so that the subject P enters the opening 13, or a platform supporting the subject P may be raised so that the subject P enters the opening 13.

[0027] A case will now be described in which the X-ray CT apparatus 1 scans the subject P in a supine position. Fig. 5 is a diagram showing an example of the subject P in a supine position. The supine position is a state in which the subject P lies on a bed (not shown).

[0028] Fig. 6 is a diagram showing an example of the appearance of the gantry 10 during scanning in a supine position according to the first embodiment. The gantry 10 shown in Fig. 6 is tilted 90 degrees from the orientation shown in Fig. 4. Therefore, as shown in Fig. 6, the opening 13 of the gantry 10 faces sideways. In this case, the gantry 10 rotates the X-ray tube 14 and the X-ray detector 15 around a rotation axis C1. The subject P, placed on the bed, enters the opening 13 from the side of the gantry 10.

[0029] The posture of the subject during scanning is not limited to lying, standing, or sitting. For example, the X-ray CT device 1 may scan the subject P in an obliquely tilted posture with the gantry device 10 and the bed device tilted obliquely.

[0030] 1, the console device 40 has a memory 41, a display 42, an input interface 43, and a processing circuit 44. Although the console device 40 will be described as being separate from the gantry device 10, the gantry device 10 may include the console device 40 or some of the components of the console device 40.

[0031] The memory 41 is realized by, for example, a semiconductor memory element such as a RAM (Random Access Memory), a flash memory, a hard disk, an optical disk, etc. The memory 41 stores, for example, projection data and reconstructed image data. The memory 41 is also an example of a storage unit. The memory 41 may be provided outside the X-ray CT device 1.

[0032] The display 42 displays various kinds of information. For example, the display 42 outputs medical images (CT images) generated by the processing circuit 44, a GUI (Graphical User Interface) for receiving various operations from an operator, and the like. For example, the display 42 is a liquid crystal display or a CRT (Cathode Ray Tube) display. The display 42 may be provided on the gantry device 10. The display 42 may be a desktop type, or may be configured as a tablet terminal capable of wireless communication with the console device 40 main body. The display 42 is an example of a display unit. The display 42 may be provided outside the X-ray CT device 1.

[0033] The input interface 43 accepts various input operations from an operator, converts the accepted input operations into electrical signals, and outputs the electrical signals to the processing circuitry 44. For example, the input interface 43 accepts from the operator acquisition conditions for acquiring projection data, reconstruction conditions for reconstructing CT images, image processing conditions for generating post-processed images from CT images, and the like. For example, the input interface 43 is realized by a trackball, a switch button, a mouse, a keyboard, a touchpad for performing input operations by touching the operation surface, a touchscreen in which a display screen and a touchpad are integrated, a non-contact input circuit using an optical sensor, a voice input circuit, and the like.

[0034] The input interface 43 is connected to the processing circuit 44, and converts the input operation received from the operator into an electrical signal and outputs it to the control circuit. In this specification, the input interface 43 is not limited to an interface having physical operation parts such as a mouse and a keyboard. For example, an example of the input interface 43 also includes an electrical signal processing circuit that receives an electrical signal corresponding to the input operation from an external input device provided separately from the device and outputs this electrical signal to the control circuit.

[0035] The input interface 43 is realized by a mouse, a keyboard, a trackball, a switch, a button, a joystick, or the like. The input interface 43 may be provided in the pedestal device 10. The input interface 43 may be configured by a tablet terminal or the like capable of wireless communication with the console device 40 main body. The input interface 43 is an example of an input unit.

[0036] The processing circuitry 44 controls the operation of the entire X-ray CT apparatus 1. More specifically, the processing circuitry 44 is a processor that reads out a program from the memory 41 and executes it to realize a function corresponding to each program. The processing circuitry 44 of this embodiment includes, for example, a system control function 441, a pre-processing function 442, a reconstruction processing function 443, an image processing function 444, a generation function 446, a specification function 447, an output function 448, and a reception function 449. The system control function 441 is an example of a system control unit. The pre-processing function 442 is an example of a pre-processing unit. The reconstruction processing function 443 is an example of a reconstruction processing unit. The image processing function 444 is an example of an image processing unit. The generation function 446 is an example of a generation unit. The specification function 447 is an example of a specification unit. The output function 448 is an example of an output unit. The reception function 449 is an example of a reception unit. The processing circuitry 44 is also an example of a processing unit.

[0037] Here, for example, each processing function of the processing circuit 44, the system control function 441, the preprocessing function 442, the reconstruction processing function 443, the image processing function 444, the generation function 446, the identification function 447, the output function 448, and the reception function 449, is stored in the memory 41 in the form of a program executable by a computer. The processing circuit 44 is a processor. For example, the processing circuit 44 realizes a function corresponding to each program by reading the program from the memory 41 and executing it. In other words, the processing circuit 44 in a state in which each program is read has each function shown in the processing circuit 44 in FIG. 1. Note that, in FIG. 1, it has been described that the processing functions performed by the system control function 441, the preprocessing function 442, the reconstruction processing function 443, the image processing function 444, the generation function 446, the identification function 447, the output function 448, and the reception function 449 are realized by a single processor, but it is also possible to configure the processing circuit 44 by combining multiple independent processors, and realize the functions by each processor executing a program. In addition, although FIG. 1 illustrates a single memory 41 storing a program corresponding to each processing function, a configuration may also be adopted in which multiple memories are distributed and the processing circuit 44 reads out the corresponding program from each individual memory.

[0038] In the above description, an example has been described in which the "processor" reads out and executes a program corresponding to each function from the memory 41, but the embodiment is not limited to this. In this embodiment, the term "processor" refers to a circuit such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), 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)). When the processor is, for example, a CPU, the processor realizes a function by reading out and executing a program stored in a memory. On the other hand, when the processor is an ASIC, instead of storing a program in the memory 41, the function is directly incorporated as a logic circuit in the circuit of the processor. Note that each processor in this embodiment is not limited to being configured as a single circuit for each processor, and may be configured as one processor by combining multiple independent circuits to realize the function. Furthermore, multiple components in FIG. 1 may be integrated into one processor to realize the functions thereof.

[0039] The system control function 441 controls various functions of the processing circuitry 44 based on an input operation received by a later-described reception function 449 from an operator via the input interface 43. The system control function 441 also controls the operation of the gantry device 10 so that data collection processing is performed under imaging conditions specified by the operator. For example, the system control function 441 controls the gantry device 10 to change its orientation, thereby scanning the subject P in a plurality of different postures.

[0040] In this embodiment, the functions of the pre-processing function 442, the reconstruction processing function 443, and the image processing function 444 are collectively referred to as an acquisition function 445. The acquisition function 445 is an example of an acquisition unit. The acquisition function 445 acquires at least one of first medical image data corresponding to the subject P in a first posture state and second medical image data corresponding to the subject P in a second posture state different from the first posture state by scanning. In this embodiment, the first medical image data and the second medical image data are CT image data obtained by scanning the subject P by the X-ray CT device 1.

[0041] More specifically, in this embodiment, the acquisition function 445 acquires both the first medical image data and the second medical image data by scanning.

[0042] Specifically, the pre-processing function 442 generates data by performing pre-processing such as logarithmic conversion processing, offset correction processing, inter-channel sensitivity correction processing, beam hardening correction, etc. on the detection data output from the DAS 18. Note that the data before pre-processing (detection data) and the data after pre-processing may be collectively referred to as projection data.

[0043] The reconstruction processing function 443 generates CT image data by performing reconstruction processing using a filtered back projection method, an iterative reconstruction method, or the like on the projection data generated by the preprocessing function 442. The CT image data is an example of medical image data in this embodiment.

[0044] The image processing function 444 converts the CT image data generated by the reconstruction processing function 443 into tomographic image data of an arbitrary cross section or three-dimensional image data by a known method based on an input operation received from an operator via the input interface 43. Note that the generation of the three-dimensional image data may be performed directly by the reconstruction processing function 443.

[0045] In this embodiment, the first medical image data obtained by scanning the subject P in the first posture state is, for example, CT image data obtained by scanning the subject P in a supine position. Hereinafter, the CT image data obtained by scanning the subject P in a supine position is referred to as supine position image data.

[0046] The second medical image data obtained by scanning the subject P in the second posture is, for example, CT image data obtained by scanning the subject P in a standing or sitting position. Hereinafter, the CT image data obtained by scanning the subject P in a standing position is referred to as standing image data, and the CT image data obtained by scanning the subject P in a sitting position is referred to as sitting image data.

[0047] Fig. 7 is a diagram showing an example of supine position image data 70 according to the first embodiment. In the example shown in Fig. 7, the supine position image data 70 is sagittal image data in which the sacrum, the fifth lumbar vertebra (L5), and the fourth lumbar vertebra (L4) of the subject P are depicted.

[0048] In this embodiment, for comparison between the supine image data 70 and the standing image data or the sitting image data, the imaging sections of the supine image data 70, the standing image data, and the sitting image data are cross sections along the direction of gravity when the standing image data and the sitting image data are scanned. In other words, the supine image data 70, the standing image data, and the sitting image data are sagittal image data or coronal image data.

[0049] The imaging range, the position of the imaging cross section, and the format of the CT image data are not limited to the example shown in Fig. 7. For example, the supine position image data 70, the standing position image data, and the sitting position image data may be three-dimensional image data.

[0050] 8 is a diagram showing an example of standing position image data 80 according to the first embodiment. The imaging range and imaging cross-sectional position of the standing position image data 80 are the same as those of the lying position image data 70. Note that, although the standing position image data 80 will be described as an example in this embodiment, the same applies to the sitting position image data.

[0051] In addition to the pre-processing function 442, the reconstruction processing function 443, and the image processing function 444, the system control function 441 may also be included in the acquisition function 445.

[0052] Returning to FIG. 1, the generating function 446 generates converted image data by performing a conversion process based on the second posture state on the first medical image data. In this embodiment, the generating function 446 generates CT image data equivalent to an upright image from the supine image data 70 by performing a conversion process based on the upright state on the supine image data 70. The CT image data generated by this conversion is called converted upright image data. The converted upright image data is an example of converted image data in this embodiment.

[0053] 9 is a diagram showing an example of the conversion process according to the first embodiment. As shown in FIG. 9, the generating function 446 generates converted upright image data 71 from, for example, supine image data 70. More specifically, the generating function 446 generates the converted upright image data 71 by performing a conversion process based on the gravity direction on the supine image data 70. The conversion process based on the gravity direction is, for example, a linear conversion process that takes into account the influence of a change in the position or shape of the imaging site of the subject P based on a load related to the gravity direction. When the subject P changes from a supine state to an upright state, the position or shape of the body tissues of the subject P, such as bones and cartilage, changes due to the load of gravity acting along the body axis direction of the subject P.

[0054] In reality, if the subject P has a lesion in the body tissue such as bone or cartilage, the degree of deformation in the direction of gravity due to weight load may differ between the lesion and the non-lesion. The conversion by the generation function 446 does not take into account the unevenness of the influence of the weight load caused by such a lesion. In other words, the converted standing image data 71 is ideal standing image data that does not have the unevenness of the influence of the weight load caused by the lesion.

[0055] 1, the identification function 447 identifies an area of ​​interest in the first medical image data or the second medical image data based on the first medical image data and the second medical image data. In this embodiment, the processing based on the first medical image data includes processing based on the converted image data generated from the first medical image data.

[0056] In this embodiment, the identification function 447 identifies the attention area based on the converted standing position image data 71 and the standing position image data 80.

[0057] In this embodiment, the attention area is a difference area where a difference occurs between the converted standing position image data 71 and the standing position image data 80.

[0058] Fig. 10 is a diagram showing an example of differential region data 90 according to the first embodiment. The differential region data 90 is image data indicating a difference between the converted standing image data 71 and the standing image data 80. As shown in Fig. 10, the identification function 447 extracts differential information between the converted standing image data 71 and the standing image data 80, and identifies a region of interest based on the differential information.

[0059] 10, there is a difference in the shape of the bone tissue between the fourth and fifth lumbar vertebrae between the converted standing image data 71 and the standing image data 80. This difference occurs, for example, when the subject P is in an upright position, and the shape of the lesion changes as the subject P is compressed in the direction of gravity by the load of the subject's body weight.

[0060] For example, a first differential region 917 in the differential region data 90 is a region where bone tissue is depicted in the converted standing image data 71 but not depicted in the standing image data 80. A second differential region 918 is a region where bone tissue is depicted in the standing image data 80 but not depicted in the converted standing image data 71. Hereinafter, the first differential region 917 and the second differential region 918 will be collectively referred to simply as differential region 91. The differential information is, for example, information indicating the position and range of the differential region 91 in the converted standing image data 71 or the standing image data 80.

[0061] The white non-difference region 901 is a region surrounded by the first difference region 917 and the second difference region 918, and is a region where bone tissue is depicted in both the converted standing image data 71 and the standing image data 80. The black background region 902 is a region where there is no difference between the converted standing image data 71 and the standing image data 80.

[0062] 10, the first differential region 917 and the second differential region 918 are collectively referred to as a differential region 91. The differential region 91 is an example of a region of interest.

[0063] In FIG. 10, the difference region 91 is an image region on the two-dimensional image of the converted upright image data 71 and the upright image data 80. For example, when the converted upright image data 71 and the upright image data 80 are two-dimensional image data depicting a sagittal section of the subject P, the identification function 447 identifies the difference between the converted upright image data 71 and the upright image data 80 by image processing. A known image processing method can be adopted as a method for identifying the difference by the identification function 447. The sagittal section is an example of the first imaging section in this embodiment. Note that, when the converted upright image data 71 and the upright image data 80 are three-dimensional image data, the difference region 91 may be a three-dimensional region.

[0064] 1, the output function 448 outputs information related to the region of interest. In this embodiment, the output function 448 causes a differential region image indicating the region of interest, i.e., the differential region 91, to be displayed on the display 42. The differential region image is an example of information related to the region of interest and an image indicating the region of interest in this embodiment.

[0065] More specifically, the output function 448 causes the display 42 to display a differential region image showing the differential region 91, a converted standing image based on the converted standing image data 71, and a standing image based on the standing image data 80 side by side. The converted standing image is an example of a converted image in this embodiment. The standing image is an example of a second medical image. Hereinafter, the screen on which the differential region image, the converted standing image, and the standing image are displayed side by side is referred to as a comparison screen.

[0066] Fig. 11 is a diagram showing an example of a comparison screen 420 according to the first embodiment. As shown in Fig. 11, the comparison screen 420 displays a differential region image 900, a converted standing image 710, and a standing image 800 side by side. Furthermore, on the differential region image 900, a first differential region 917 and a second differential region 918 are displayed in different display modes. For example, the first differential region 917 and the second differential region 918 may be displayed in different colors.

[0067] 11, in order to allow the user to easily understand that the converted upright image 710 is an image based on the supine image data 70 obtained by scanning the subject P in a supine position, "supine position" may be displayed near the converted upright image 710. In the example shown in FIG. 11, "upright position" is also displayed near the upright image 800.

[0068] Furthermore, the output function 448 may display an image indicating a portion corresponding to the differential region 91 on the converted standing image 710 or the standing image 800. In the example shown in Fig. 11, the output function 448 displays an arrow image 801 on the standing image 800, indicating a portion corresponding to the differential region 91 on the standing image 800.

[0069] In addition, the output function 448 may display auxiliary lines 930a, 930b indicating the positional relationship between the differential region image 900 and the transformed standing image 710 and the standing image 800, in order to make it easier for the user to understand the position corresponding to the differential region image 900 on the transformed standing image 710 and the standing image 800.

[0070] A doctor or technician can easily grasp the position and size of the part affected by the weight load by visually checking the comparison screen 420. For example, the doctor or technician judges the severity of the lesion of the subject P based on the position and size of the part affected by the weight load grasped from the comparison screen 420.

[0071] Note that the method of output by the output function 448 is not limited to displaying on the display 42. For example, the output function 448 may transmit the differential region image 900, the converted standing image 710, and the standing image 800 to another information processing device.

[0072] 1, the reception function 449 receives various operations by the user via the input interface 43. For example, the reception function 449 receives designation of the orientation of the gantry device 10 and other imaging conditions by the user.

[0073] Next, a process flow for comparing image data scanned in different postures by the X-ray CT apparatus 1 configured as above will be described.

[0074] FIG. 12 is a diagram illustrating an example of a processing flow according to the first embodiment.

[0075] First, the system control function 441 of the X-ray CT apparatus 1 controls the operation of the gantry device 10 to execute a supine scan for scanning the subject P in a supine position (S1). Detection data collected by the supine scan is transferred from the DAS 18 to the console device 40.

[0076] Next, the system control function 441 controls the operation of the gantry device 10 to perform an upright scan to scan the subject P in an upright position (S2). Detection data collected by the upright scan is transferred from the DAS 18 to the console device 40. Note that, although the supine scan is performed first in the example shown in FIG. 12, the upright scan may be performed first.

[0077] Then, the acquisition function 445 acquires supine image data 70 based on the supine scan (S3). More specifically, the preprocessing function 442 preprocesses the detection data collected by the supine scan executed by the system control function 441, and the reconstruction processing function 443 reconstructs the preprocessed data. Then, the image processing function 444 generates the supine image data 70 from the reconstructed data.

[0078] Next, the generating function 446 generates converted standing position image data 71 from the lying position image data 70 (S4).

[0079] Moreover, the acquisition function 445 acquires the upright image data 80 based on the upright scan (S5). More specifically, the preprocessing function 442 preprocesses the detection data collected by the upright scan executed by the system control function 441, and the reconstruction processing function 443 reconstructs the preprocessed data. Then, the image processing function 444 generates the upright image data 80 from the reconstructed data.

[0080] Then, the identification function 447 extracts difference information between the converted standing position image data 71 and the standing position image data 80, and identifies the attention area based on the difference information (S6). In this embodiment, the attention area is the difference area 91.

[0081] Then, the identification function 447 generates image data indicating the region of interest, that is, differential region data 90 indicating the differential region 91 (S7).

[0082] Then, the output function 448 causes the display 42 to display the comparison screen 420, which displays the differential region image 900, the converted standing image 710, and the standing image 800 side by side (S8). Here, the processing of this flowchart ends.

[0083] In this way, the X-ray CT device 1 of this embodiment acquires the supine image data 70 and the upright image data 80 by scanning, identifies a region of interest in the supine image data 70 or the upright image data 80 based on the supine image data 70 and the upright image data 80, and outputs information about the region of interest. Therefore, according to the X-ray CT device 1 of this embodiment, a doctor, technician, or the like can easily understand the results of comparing multiple medical images taken in different postures.

[0084] For example, in the field of orthopedics, a doctor or technician may identify the location of a lesion or determine the severity of the lesion by comparing different CT image data obtained by scanning the subject P in different postures. In such a case, if the doctor or technician simply visually checks the lying image data 70 and the standing image data 80 individually, the accuracy of the image comparison depends on the ability of the doctor or technician, and the result of the determination may vary or be lacking in objectivity. In contrast, according to the X-ray CT device 1 of this embodiment, by outputting information about the region of interest based on the lying image data 70 and the standing image data 80, the doctor or technician can easily grasp useful information about the location of the lesion or the severity of the lesion without visually checking the difference between the lying image data 70 and the standing image data 80.

[0085] In this embodiment, the first medical image data is supine image data 70 obtained by scanning the subject P in a supine position, and the second medical image data is upright image data 80 obtained by scanning the subject P in an upright position. Therefore, according to the X-ray CT device 1 of this embodiment, by identifying a region of interest based on a plurality of medical image data in which the subject P has different orientations relative to the direction of gravity, it becomes easier to identify a region that is more affected by the weight load than other regions.

[0086] Furthermore, when one X-ray CT device 1 of this embodiment is capable of scanning both the supine image data 70 and the upright image data 80, the time interval between the supine scan and the upright scan can be made shorter than when multiple imaging devices are used to perform separate scans. This makes it easier to capture both the supine image data 70 and the upright image data 80 before the condition of the diseased area of ​​the subject P changes. Furthermore, when one X-ray CT device 1 is capable of scanning both the supine image data 70 and the upright image data 80, the effects of differences in image quality due to the characteristics of the individual devices can be eliminated.

[0087] Moreover, the X-ray CT device 1 of this embodiment performs a conversion process based on the upright position on the supine image data 70 to generate converted upright image data 71, and identifies a region of interest based on the converted upright image data 71 and the upright image data 80. More specifically, the X-ray CT device 1 of this embodiment performs a conversion process based on the gravity direction on the supine image data 70 to generate the converted upright image data 71. Therefore, according to the X-ray CT device 1 of this embodiment, it is easier to identify a region where an uneven effect of weight load due to a diseased area or the like occurs than by simply comparing the supine image data 70 and the upright image data 80.

[0088] Moreover, the X-ray CT apparatus 1 of this embodiment displays a difference region image 900 indicating the region of interest on the display 42. Therefore, according to the X-ray CT apparatus 1 of this embodiment, the region of interest can be clearly presented to a doctor, a technician, or the like.

[0089] Moreover, the X-ray CT device 1 of this embodiment extracts difference information between the lying image data 70 and the upright image data 80, and identifies a region of interest based on the difference information. Therefore, the X-ray CT device 1 of this embodiment allows a doctor or technician to easily grasp the difference between the lying image data 70 and the upright image data 80 caused by a lesion, etc., and can assist in identifying the position of the lesion or determining the severity of the lesion. In this embodiment, the lying image data 70 and the upright image data 80 are indirectly compared by comparing the difference information between the lying image data 70 and the upright image data 80 with the converted upright image data 71 generated from the lying image data 70.

[0090] Furthermore, the X-ray CT device 1 of this embodiment displays the difference region image 900, the transformed standing image 710, and the standing image 800 side by side on the display 42. Therefore, according to the X-ray CT device 1 of this embodiment, a doctor or technician can visually confirm the transformed standing image 710 and the standing image 800, which are the comparison targets, and the difference region image 900, which is the comparison result, at once, so that the doctor or technician can easily confirm not only the area where the influence of the weight load due to the diseased area or the like is uneven, but also the surrounding areas.

[0091] Second Embodiment In the first embodiment described above, the X-ray CT device 1 displayed the differential region image 900, the converted upright image 710, and the upright image 800 side by side on the display 42, but in this second embodiment, an image showing the region of interest in another display mode is displayed on the display 42.

[0092] The X-ray CT apparatus 1 of this embodiment includes a gantry device 10 and a console device 40, similar to the first embodiment. Also, the processing circuitry 44 of the console device 40 includes a system control function 441, a pre-processing function 442, a reconstruction processing function 443, an image processing function 444, a generating function 446, a specifying function 447, an output function 448, and a reception function 449, similar to the first embodiment. The system control function 441, the pre-processing function 442, the reconstruction processing function 443, the image processing function 444, the generating function 446, the specifying function 447, and the reception function 449 include the same functions as those of the first embodiment.

[0093] In addition to the functions of the first embodiment, the output function 448 of this embodiment highlights an image showing a region of interest on a third medical image depicting a second imaging section different from the first imaging section of the subject P. In this embodiment, the first imaging section is, for example, a sagittal section, and the second imaging section is an axial section.

[0094] Fig. 13 is a diagram showing an example of the position of the second imaging section according to the second embodiment. In Fig. 13, the position of the second imaging section 60 corresponds to a differential region 91 of the subject P in an upright position.

[0095] The output function 448 of this embodiment displays an image showing a differential region on an axial image generated from standing image data 80 obtained by scanning the subject P in a standing position. The image showing a differential region displayed on the axial image is an example of information about a region of interest and an image showing a region of interest in this embodiment.

[0096] Fig. 14 is a diagram showing an example of an axial image 610 according to the second embodiment. As shown in Fig. 14, the output function 448 displays an image representing a difference region 91 identified by the identification function 447 as a difference between the converted standing image data 71 and the standing image data 80 on the axial image 610. Specifically, in Fig. 14, a first difference region 917a, a second difference region 918a, and a non-difference region 901a are displayed on the axial image 610 displayed on the display 42. The axial image 610 is an example of a third medical image in this embodiment.

[0097] The lumbar vertebrae 912a, 912b displayed as the background of the first differential region 917a, the second differential region 918a, and the non-differential region 901a are depicted in the standing image data 80. When the output function 448 displays the differential region 91 identified by comparing the transformed standing image data 71 with the standing image data 80 on the axial image 610, the output function 448 may use bones such as the lumbar vertebrae as a reference for the display position.

[0098] Furthermore, in this embodiment, the output function 448 highlights the first differential region 917a and the second differential region 918a on the axial image 610. Highlighting refers to displaying the first differential region 917a and the second differential region 918a with greater emphasis than other regions. The method of highlighting is not particularly limited, but for example, the output function 448 may display the first differential region 917a and the second differential region 918a in a color different from other portions.

[0099] The output function 448 may display the axial image 610 shown in Fig. 14 in the comparison screen 420 shown in Fig. 11. Also, the output function 448 may display only the axial image 610 on the display 42 without displaying the comparison screen 420.

[0100] In this way, according to the X-ray CT device 1 of this embodiment, an image showing the region of interest is highlighted on an image showing an imaging section different from the imaging section used to identify the region of interest, allowing a doctor, technician, etc. to check the region of interest from various angles.

[0101] In this embodiment, the output function 448 displays the first difference region 917a and the second difference region 918a on the axial image 610, but the first difference region 917a and the second difference region 918a may be displayed on another image. For example, the output function 448 may display the first difference region 917a and the second difference region 918a on the standing image 800, the lying image, or the converted standing image 710. In this case, the output function 448 may highlight the first difference region 917a and the second difference region 918a. The image in which the first difference region 917a and the second difference region 918a are displayed may be a sagittal image or a coronal image.

[0102] (Third embodiment) In this third embodiment, furthermore, a reduction in the storage capacity of CT image data will be described.

[0103] Fig. 15 is a block diagram showing an example of an X-ray CT apparatus 1 according to the third embodiment. As in the first embodiment, the X-ray CT apparatus 1 of this embodiment includes a gantry device 10 and a console device 40. The X-ray CT apparatus 1 shown in Fig. 15 is an example of a medical image diagnostic apparatus and a medical image processing apparatus in this embodiment.

[0104] Further, the processing circuit 44 of the console device 40 includes a system control function 441, a preprocessing function 442, a reconstruction processing function 443, an image processing function 444, a generation function 446, an identification function 447, an output function 448, a reception function 449, a writing function 450, and a restoration function 451. The identification function 447 in this embodiment is an example of an identification unit and an extraction unit. The writing function 450 is an example of a data writing unit. The restoration function 451 is an example of a restoration unit.

[0105] In this embodiment, similarly to the first embodiment, the functions of the pre-processing function 442, the reconstruction processing function 443, and the image processing function 444 are collectively referred to as the acquisition function 445. The restoration function 451 is an example of a restoration unit. The system control function 441, the pre-processing function 442, the reconstruction processing function 443, the image processing function 444, the acquisition function 445, the generation function 446, the output function 448, and the reception function 449 have the same functions as those in the first embodiment.

[0106] Specifically, the acquisition function 445 acquires first medical image data obtained by scanning the subject P in a first posture and second medical image data obtained by scanning the subject P in a second posture different from the first posture, similar to the first embodiment. For example, the acquisition function 445 acquires supine image data 70 and standing image data 80.

[0107] In addition to the same functions as those in the first embodiment, the identification function 447 of this embodiment extracts difference data between the first medical image data and the second medical image data. For example, the identification function 447 extracts difference data between the supine image data 70 and the upright image data 80.

[0108] The writing function 450 stores the difference data and the second medical image data in the memory 41. Moreover, the writing function 450 does not store the first medical image data in the memory 41.

[0109] 16 is a diagram showing an example of data to be saved according to the third embodiment. As shown in the figure, among the lying position image data 70, the standing position image data 80, and the difference data 92, the writing function 450 selects the lying position image data 70 as a deletion target, and selects the standing position image data 80 and the difference data 92 as a saving target in the memory 41. The difference data 92 is assumed to have a smaller data size than the lying position image data 70 and the standing position image data 80.

[0110] 15, the restoration function 451 restores the lying position image data 70 based on the difference data 92 and the standing position image data 80 stored in the memory 41. The timing of the restoration is not particularly limited, but the restoration function 451 performs the restoration when, for example, the reception function 449 receives an instruction from the user to restore the lying position image data 70.

[0111] In this manner, the X-ray CT device 1 of this embodiment extracts the difference data between the supine image data 70 and the upright image data 80, and stores the difference data and the upright image data 80 in the memory 41. The X-ray CT device 1 of this embodiment also restores the supine image data 70 based on the difference data 92 and the upright image data 80 stored in the memory 41. Therefore, according to the X-ray CT device 1 of this embodiment, it is possible to reduce the storage capacity required for storing CT image data compared to storing both the first medical image data and the second medical image data.

[0112] Furthermore, the X-ray CT device 1 of this embodiment can not only simply delete the supine image data 70, but can also restore the supine image data 70 based on the difference data 92 and the upright image data 80 stored in the memory 41, allowing the user to use the supine image data 70 when necessary.

[0113] In the present embodiment, the lying position image data 70 is an example of the first image data and the standing position image data 80 is an example of the second image data, but the standing position image data 80 may be an example of the first image data and the lying position image data 70 may be an example of the second image data. When the standing position image data 80 is an example of the first image data and the lying position image data 70 is an example of the second image data, the writing function 450 selects the standing position image data 80 as a deletion target among the lying position image data 70, the standing position image data 80, and the difference data 92, and selects the lying position image data 70 and the difference data 92 as a storage target in the memory 41.

[0114] In the present embodiment, the identifying function 447 is an example of an extracting section, but the processing circuit 44 may be provided with an extracting function in addition to the identifying function 447.

[0115] (Variation 1) In each of the above-described embodiments, the generation function 446 generates the converted standing image data 71 by performing a conversion process based on the gravity direction on the lying image data 70, but the conversion method is not limited to this.

[0116] The generation function 446 of this modified example generates converted standing image data 71 by performing a conversion process on the lying position image data 70 using a trained model.

[0117] The trained model is, for example, a model trained using a plurality of supine image data and upright image data in which the same subject as each of the plurality of supine image data is scanned as teacher data. The trained model is, for example, a trained model generated by deep learning such as a neural network.

[0118] As a deep learning technique, a multi-layer neural network such as a Convolutional Neural Network (CNN) can be applied, but is not limited to this.

[0119] In addition, the trained model may be incorporated into the generation function 446, or the generation function 446 may read the trained model from the memory 41 and execute it.

[0120] (Variation 2) The generating function 446 may simply perform a conversion process on the lying position image data 70 without taking into account the direction of gravity. For example, the generating function 446 may generate the converted standing position image data 71 from the lying position image data 70 by a simple linear conversion.

[0121] (Variation 3) Furthermore, the X-ray CT device 1 may be configured without the generating function 446. In this case, since the lying image data 70 is not converted into the converted upright image data 71, for example, the identifying function 447 identifies the region of interest by comparing the lying image data 70 with the upright image data 80. For example, the identifying function 447 may identify a region where there is a difference between the lying image data 70 and the upright image data 80 as the region of interest. When comparing with the upright image data 80, the lying image data 70 is rotated 90 degrees to align the orientation.

[0122] In this modification, an area where there is a difference between the lying position image data 70 and the standing position image data 80 is an example of a region of interest.

[0123] In this case, the output function 448 causes the display 42 to display information indicating the difference between the lying position image data 70 and the standing position image data 80.

[0124] (Variation 4) In addition, in each of the above-described embodiments, the X-ray CT device 1 actually performs a supine scan and an upright scan to obtain the supine image data 70 and the upright image data 80, but the image data to be obtained is not limited to this.

[0125] For example, the acquisition function 445 of this modification may acquire only the supine image data 70. In this modification, the converted standing image data 71 generated by the generation function 446 performing a conversion process on the supine image data 70 may be an example of the second medical image data.

[0126] (Variation 5) In addition, in each of the above-described embodiments, the X-ray CT device 1 is capable of both supine scanning and upright scanning, but may be capable of only one of them. For example, if the X-ray CT device 1 is capable of supine scanning but not upright scanning, the acquisition function 445 of the X-ray CT device 1 may acquire upright image data 80 from another X-ray CT device capable of upright scanning.

[0127] (Variation 6) In addition, in each of the above-mentioned embodiments, the supine image data 70 is an example of the first image data, and the standing image data 80 is an example of the second image data, but the first image data and the second image data are not limited to this. For example, the standing image data 80 or the sitting image data may be an example of the first image data, and the supine image data 70 may be an example of the second image data. In this case, the generating function 446 may generate the converted supine image data from the standing image data 80 or the sitting image data. Also, instead of the standing scan, a scan may be performed with pressure applied from the head side and the leg side of the subject P in a supine position.

[0128] (Variation 7) Furthermore, the output function 448 may cause the display 42 to display numerical information based on the difference information.

[0129] Fig. 17 is a diagram showing an example of display of numerical information according to the second modification. A line 50 shown in Fig. 17 is a line drawn on an axial image 610 by a user operating an input interface 43 such as a mouse. The output function 448 displays the length of the line 50 on the screen in the real world near the line 50. In the example shown in Fig. 17, numerical information 51 such as "xx cm" is displayed on the axial image 610. The output function 448 may obtain the numerical information 51 from the dimensions of the imaging field of view of a supine scan or an upright scan, for example.

[0130] In addition, in FIG. 17, it is described that the user draws the line 50 at the desired position, but the output function 448 may also calculate the dimensions of the differential region 91 and display a numerical value representing the dimensions of the differential region 91 on the display 42.

[0131] 18 is a diagram showing another example of display of numerical information according to Modification 2. In the example shown in FIG. 18, the output function 448 displays a scale image 52 in the vicinity of the position where the differential region 91 is depicted on the axial image 610. The scale image 52 is, for example, an image on which a scale is drawn at every image position equivalent to 1 cm in the real world. The scale image 52 is also an example of numerical information. The scale image 52 is displayed or hidden in response to, for example, a user operation.

[0132] Displaying such numerical information makes it easy for doctors or technicians to grasp the size of the lesion. Although an axial image 610 is shown as an example in FIGS. 17 and 18, numerical information may be displayed on other images.

[0133] (Variation 8) In the above-described embodiments, the output function 448 displays the comparison screen 420 and the axial image 610 on the display 42, but the information to be displayed is not limited to this.

[0134] For example, the output function 448 may cause the display 42 to display a notification according to the size of the differential region 91, or an estimated result of the severity of the lesion in the subject P, or the like.

[0135] For example, when the converted standing position image data 71 and the standing position image data 80 include three or more lumbar vertebrae, the identifying function 447 may compare the intervals between the lumbar vertebrae and cause the output function 448 to display the comparison result.

[0136] Specifically, when the transformed standing image data 71 and the standing image data 80 include the third lumbar vertebra, the fourth lumbar vertebra, and the fifth lumbar vertebra, the identification function 447 compares the magnitude of the difference between the distance between the third lumbar vertebra and the fourth lumbar vertebra in the transformed standing image data 71 and the distance between the third lumbar vertebra and the fourth lumbar vertebra in the standing image data 80, and the magnitude of the difference between the distance between the fourth lumbar vertebra and the fifth lumbar vertebra in the transformed standing image data 71 and the distance between the fourth lumbar vertebra and the fifth lumbar vertebra in the standing image data 80, and when either difference is greater than the other by a threshold value or more, the part where the difference greater than the threshold value occurs may be identified as the area of ​​interest.

[0137] The comparison of the magnitude of the difference may be a comparison of the size of the area on the axial image 610 or the sagittal image, or, if the CT image data is three-dimensional image data, a comparison of the size of the volume.

[0138] The identifying function 447 may also determine whether or not a notification is required depending on the ratio of the areas of the first differential region 917, the second differential region 918, and the non-differential region 901 on the axial image 610 or the sagittal image. For example, the identifying function 447 may determine that a notification is required when the ratio of the first differential region 917 and the second differential region 918 to the total area of ​​the first differential region 917, the second differential region 918, and the non-differential region 901 on the image is equal to or greater than a threshold. In this case, the output function 448 causes the display 42 to display a notification to inform the user that the ratio of the size of the differential region 91 shown in the part including the differential region 91 is equal to or greater than a specified threshold. The identifying function 447 may use not only the area ratio but also the volume ratio in the three-dimensional image data to determine whether or not a notification is required.

[0139] (Variation 9) In each of the above-described embodiments, the X-ray CT device 1 is an example of a medical image diagnostic device and a medical image processing device, but a modality other than the X-ray CT device 1 may be an example of a medical image diagnostic device and a medical image processing device. For example, other medical image diagnostic devices such as a Magnetic Resonance Imaging (MRI) device, an ultrasonic diagnostic device, a PET (Positron Emission Tomography) device, an X-ray diagnostic device, and a SPECT (Single Photon Emission Computed Tomography) device may be an example of a medical image diagnostic device and a medical image processing device.

[0140] Also, an information processing device other than the modality, for example, an external workstation, server, or PC (Personal Computer) may be an example of a medical image processing device. In this case, the processing circuit of the external workstation, server, or PC includes the acquisition function 445, the generation function 446, the identification function 447, the output function 448, the reception function 449, the writing function 450, and the restoration function 451 described in Fig. 1 or Fig. 15. In this case, the acquisition function 445 acquires the first medical image data and the second medical image data from the modality.

[0141] The various data handled in this specification are typically digital data.

[0142] According to at least one of the embodiments described above, it is possible to at least one of facilitate the understanding of the comparison results of multiple medical images taken in different postures and reduce the storage capacity of CT image data.

[0143] 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]

[0144] 1 X-ray CT device 10 Mounting device 40 Console device 41 Memory 42 Display 43 Input Interface 44 Processing circuit 50 lines 51 Numerical Information 52 Scale Image 60 Second Imaging Section 70 Supine image data 71 Transformed standing image data 80 Standing image data 90 Differential Area Data 91 Difference area 92 Differential Data 420 Comparison screen 441 System Control Functions 442 Pre-processing function 443 Reconstruction Processing Function 444 Image Processing Function 445 Acquisition Function 446 Generation function 447 Specific Functions 448 Output Function 449 Reception Function 450 Write function 451 Restoration Function 610 Axial Images 800 standing images 801 Arrow Images 900 Difference Region Images 901,901a Non-differential region 917,917a First difference region 918,918a Second difference domain 930a, 930b auxiliary lines

Claims

1. A storage unit; an acquisition unit that acquires first medical image data obtained by scanning a subject in a first posture state and second medical image data obtained by scanning the subject in a second posture state different from the first posture state; an extraction unit that extracts difference data between the first medical image data and the second medical image data; a data writing unit that stores the difference data and the second medical image data in the storage unit; a restoration unit that restores the first medical image data based on the difference data and the stored second medical image data; A medical image processing device comprising:

2. The data writing unit does not store the first medical image data in the storage unit. The medical image processing device according to claim 1 .

3. The difference data has a data size smaller than the first medical image data and the second medical image data. The medical image processing device according to claim 1 .

4. A reception unit that receives a restoration instruction from a user is further provided, The restoration unit restores the first medical image data when the reception unit receives the instruction. The medical image processing device according to claim 1 .

5. The first posture is a lying position, and the second posture is a standing position or a sitting position. The medical image processing device according to claim 1 .

6. a generating unit that generates converted image data by performing a conversion process based on the second posture state on the first medical image data; and an output unit that causes a display unit to display first text information indicating the first posture state in association with a converted image based on the converted image data, and causes the display unit to display second text information indicating the second posture state in association with a second medical image based on the second medical image data. The medical image processing device according to claim 1 .

7. The first medical image data and the second medical image data are medical image data captured by a same medical image diagnostic device. The medical image processing device according to claim 1 .

8. The first medical image data is captured by a first medical image diagnostic apparatus, and the second medical image data is captured by a second medical image diagnostic apparatus different from the first medical image diagnostic apparatus. The medical image processing device according to claim 1 .

9. Further comprising an output unit for displaying the restored first medical image data on a display unit. The medical image processing device according to claim 1 .

10. an acquisition unit that acquires, by scanning, at least one of first medical image data corresponding to a subject in a first posture state and second medical image data corresponding to the subject in a second posture state different from the first posture state; An identification unit that identifies an area of ​​interest in the first medical image data or the second medical image data based on the first medical image data and the second medical image data; an output unit that displays, on a display unit, at least one of a notification according to the size of the region of interest and an estimation result of the severity of the lesion of the subject; A medical image processing device comprising:

11. a generating unit that generates converted image data by performing a conversion process on the first medical image data based on the second posture state, The identification unit extracts difference information between the converted image data and the second medical image data, and identifies a difference region where there is a difference between the converted image data and the second medical image data as a region of interest in the first medical image data or the second medical image data; the output unit causes the display unit to display at least one of a notification according to the size of the difference region and an estimation result of the severity of the lesion of the subject. The medical image processing device according to claim 10.

12. the generating unit generates the converted image data by performing a conversion process on the first medical image data based on a gravity direction in the second posture state; The conversion process does not reflect the inequality of the effect of weight bearing on a lesion and a portion other than the lesion present inside the subject. The medical image processing device according to claim 11.

13. the specifying unit determines whether or not the notification is necessary according to a ratio of an area or volume of the differential region to an area or volume of a non-differential region in which the same tissue is depicted in both the converted image data and the second medical image data; The output unit causes the display unit to display the notification based on a result of the determination by the identification unit. The medical image processing device according to claim 11.

14. the converted image data and the second medical image data are two-dimensional image data depicting a cross section of the subject, the specifying unit determines that the notification is required when a ratio of an area of ​​the differential region to a total area of ​​the differential region and the non-differential region in the second medical image data is equal to or greater than a threshold. The medical image processing device according to claim 13.

15. the identification unit determines that the converted image data and the second medical image data are three-dimensional image data, the identification unit determines that the notification is required when a ratio of a volume of the differential region to a total volume of a non-difference region in which the same tissue is depicted in both the converted image data and the second medical image data in the second medical image data is equal to or greater than a threshold value. The medical image processing device according to claim 11.

16. an acquisition unit that acquires, by scanning, at least one of first medical image data corresponding to a subject in a first posture state and second medical image data corresponding to the subject in a second posture state different from the first posture state; a generating unit that generates converted image data by performing a conversion process based on the second posture state on the first medical image data; a determination unit that compares intervals between adjacent structures among a first structure, a second structure, and a third structure inside the subject that are included in the converted image data and the second medical image data; an output unit that displays a comparison result by the determination unit on a display unit; A medical image processing device comprising:

17. the identification unit identifies a region of interest in the first medical image data or the second medical image data based on a difference between a distance between the first structure and the second structure adjacent to the first structure in the converted image data and a distance between the first structure and the second structure in the second medical image data, a distance between the second structure and the third structure adjacent to the second structure in the converted image data, and a difference between a distance between the second structure and the third structure in the second medical image data; The medical image processing device according to claim 16.

Images