Information processing apparatus, information processing method, and program

Abstract

To improve the extraction accuracy in extracting a region of a predetermined organ from a medical image, and the calculation accuracy of various measurements based on the region.SOLUTION: An image information processing apparatus includes an acquisition unit, a setting unit, a calculation unit, and a correction unit. The acquisition unit acquires a structure from a medical image. The setting unit sets lines or planes that divide the structure into a plurality of regions. The calculation unit calculates feature quantities related to a form of the structure for each of the regions. The correction unit corrects the structure such that a difference in the feature quantities is reduced.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The embodiments disclosed in this specification and the drawings relate to an information processing apparatus, an information processing method, and a program.

Background Art

[0002] When formulating a treatment plan using medical images, the region of a predetermined organ is extracted from the medical images, and various measurement values are calculated from the region. For example, the region of an organ can be extracted from medical images by machine learning or the like, and various measurement values can be calculated from the extracted region.

[0003] However, in conventional organ segmentation processing using machine learning or the like, even when an organ has anatomical features with left-right symmetry, the left-right symmetry of the organ is not fully considered, so results that conflict with the anatomical features may be calculated. Also, when simply making the organ segmentation processing symmetric with respect to the reference axis and performing processing such as averaging the left and right data centered on the reference axis, the left-right symmetry of the anatomical features is maintained, but the anatomical structure often differs from the actual form.

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

Problems 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 improve the extraction accuracy when extracting the region of a predetermined organ from a medical image and the calculation accuracy of various measurement values based on the region. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problems. The problems corresponding to the effects of each configuration shown in the embodiments described later can also be regarded as other problems.

Means for Solving the Problems

[0006] The information processing apparatus according to the embodiment includes an acquisition unit, a setting unit, a calculation unit, and a correction unit. The acquisition unit acquires a structure from a medical image. The setting unit sets a line or plane that divides the structure into a plurality of regions. The calculation unit calculates a feature amount related to the form of the structure for each of the plurality of regions. The correction unit corrects the structure so that the difference in the feature amounts becomes small.

Brief Description of the Drawings

[0007]

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[0008] Hereinafter, embodiments of an information processing apparatus, an information processing method, and a program will be described in detail with reference to the drawings.

[0009] (First Embodiment) FIG. 1 shows a configuration example of an information processing apparatus 140 according to the embodiment. In the case of FIG. 1, a case where the information processing apparatus 140 according to the embodiment is a part of an X-ray CT apparatus 101 is described. Note that the information processing apparatus 140 is not limited to being a part of the X-ray CT apparatus 101, and may be a part of a medical image diagnostic apparatus other than the X-ray CT apparatus, such as an ultrasonic diagnostic apparatus or a magnetic resonance imaging apparatus. As another example, the information processing apparatus 140 may be configured independently of these medical image diagnostic apparatuses.

[0010] As shown in FIG. 1, the X-ray CT apparatus 101 according to the embodiment includes a gantry device 110, a bed device 130, and an information processing device 140. Note that FIG. 1 depicts the gantry device 110 from multiple directions for explanatory purposes and shows the case where the X-ray CT apparatus 101 has one gantry device 110.

[0011] The gantry device 110 includes an X-ray tube 111, an X-ray detector 112, a rotating frame 113, an X-ray high voltage device 114, a control device 115, a wedge 116, a collimator 117, and a DAS (Data Acquisition System) 118.

[0012] The X-ray tube 111 is a vacuum tube having a cathode (filament) that generates thermoelectrons and an anode (target) that generates X-rays upon receiving the collision of thermoelectrons. The X-ray tube 111 generates X-rays to irradiate the subject P by irradiating thermoelectrons from the cathode toward the anode by applying a high voltage from the X-ray high voltage device 114. For example, the X-ray tube 111 includes a rotating anode type X-ray tube that generates X-rays by irradiating a rotating anode with thermoelectrons.

[0013] Note that the X-ray tube 111 and the control device 115 are an example of an X-ray irradiation unit. The X-ray irradiation unit performs a low-flux scan on a phantom composed of a known substance and a transmission length. Specifically, the X-ray irradiation unit performs a low-flux scan by performing an air scan and a scan on a phantom composed of a plurality of different substances with an initial current intensity and each tube voltage setting of the X-ray tube.

[0014] The rotating frame 113 is an annular frame that supports the X-ray tube 111 and the X-ray detector 112 opposite to each other and rotates the X-ray tube 111 and the X-ray detector 112 by the control device 115. For example, the rotating frame 113 is a casting made of aluminum. Note that in addition to the X-ray tube 111 and the X-ray detector 112, the rotating frame 113 can further support the X-ray high voltage device 114, the wedge 116, the collimator 117, the DAS 118, and the like. Further, the rotating frame 113 can further support various configurations not shown in FIG. 1.

[0015] The wedge 116 is a filter for adjusting the X-ray dose irradiated from the X-ray tube 111. Specifically, the wedge 116 is a filter that transmits and attenuates the X-rays irradiated from the X-ray tube 111 so that the distribution of the X-rays irradiated from the X-ray tube 111 to the subject P becomes a predetermined distribution. For example, the wedge 116 is a wedge filter or a bow-tie filter, and is a filter made of aluminum or the like processed to have a predetermined target angle and a predetermined thickness.

[0016] The collimator 117 is a lead plate or the like for narrowing down the irradiation range of the X-rays that have passed through the wedge 116, and forms a slit by a combination of a plurality of lead plates or the like. Note that the collimator 117 may also be called an X-ray aperture. In FIG. 1, the case where the wedge 116 is disposed between the X-ray tube 111 and the collimator 117 is shown, but the collimator 117 may be disposed between the X-ray tube 111 and the wedge 116. In this case, the wedge 116 transmits and attenuates the X-rays irradiated from the X-ray tube 111 and whose irradiation range is restricted by the collimator 117.

[0017] The X-ray high-voltage device 114 has electric circuits such as a transformer and a rectifier, and includes a high-voltage generator that generates a high voltage applied to the X-ray tube 111, and an X-ray control device that controls the output voltage according to the X-rays generated by the X-ray tube 111. The high-voltage generator may be of a transformer type or an inverter type. Note that the X-ray high-voltage device 114 may be provided on the rotating frame 113, or may be provided on a fixed frame (not shown).

[0018] The control device 115 includes a processing circuit having a CPU (Central Processing Unit) or the like, and a drive mechanism such as a motor and an actuator. The control device 115 receives an input signal from the input interface 143 and controls the operations of the gantry device 110 and the bed device 130. For example, the control device 115 controls the rotation of the rotating frame 113, the tilt of the gantry device 110, the operations of the bed device 130 and the top plate 133, and the like. Note that the control device 115 may be provided in the gantry device 110 or may be provided in the information processing device 140.

[0019] The X-ray detector 112 is, for example, a photon counting type detector or an energy integrating type detector. When the X-ray detector 112 is a photon detection type detector, the X-ray detector 112 outputs a signal capable of measuring the energy value of an X-ray photon, which is an X-ray photon derived from the X-ray irradiated from the X-ray tube 111 and transmitted through the subject P, each time an X-ray photon is incident. The X-ray detector 112 has a plurality of X-ray detection elements that output an electrical signal (analog signal) of one pulse each time an X-ray photon is incident.

[0020] The X-ray detection element is, for example, a semiconductor element (semiconductor detection element) such as CdTe (cadmium telluride) or CdZnTe (cadmium zinc telluride), with an anode electrode and a cathode electrode arranged thereon.

[0021] The X-ray detector 112 includes a plurality of X-ray detection elements and an ASIC (Application Specific Integrated Circuit) that is connected to the X-ray detection elements and counts the X-ray photons detected by the X-ray detection elements. The ASIC counts the number of X-ray photons incident on the detection elements by discriminating the individual charges output by the X-ray detection elements. Further, the ASIC measures the energy of the counted X-ray photons by performing arithmetic processing based on the magnitude of the individual charges. Furthermore, the ASIC outputs the counting result of the X-ray photons as digital data to the DAS 118.

[0022] The DAS 118 generates detection data based on the result of the counting process input from the X-ray detector 112. The detection data is, for example, a sinogram. The sinogram is data arranging the results of the counting process incident on each X-ray detection element at each position of the X-ray tube 111. The sinogram is data arranging the results of the counting process in a two-dimensional orthogonal coordinate system with the view direction and the channel direction as axes. The DAS 118 generates, for example, a sinogram in units of columns in the slice direction in the X-ray detector 112. The DAS 118 transfers the generated detection data to the information processing apparatus 140. The DAS 118 is realized by, for example, a processor.

[0023] The data generated by the DAS 118 is transmitted from a transmitter having a light emitting diode (LED) provided in the rotating frame 113 to a receiver having a photodiode provided in a non-rotating part (for example, a fixed frame etc., illustration in FIG. 1 is omitted) of the gantry apparatus 110 by optical communication, and then transferred to the information processing apparatus 140. Here, the non-rotating part is, for example, a fixed frame that rotatably supports the rotating frame 113. Note that the method of transmitting data from the rotating frame 113 to the non-rotating part of the gantry apparatus 110 is not limited to optical communication, and any non-contact type data transmission method may be adopted, or a contact type data transmission method may be adopted.

[0024] The stretcher apparatus 130 is an apparatus for placing and moving a subject P to be imaged, and includes a base 131, a stretcher driving apparatus 132, a top plate 133, and a support frame 134. The base 131 is a housing that supports the support frame 134 so as to be movable in the vertical direction. The stretcher driving apparatus 132 is a driving mechanism that moves the top plate 133 on which the subject P is placed in the major axis direction of the top plate 133, and includes a motor, an actuator, etc. The top plate 133 provided on the upper surface of the support frame 134 is a plate on which the subject P is placed. Note that the stretcher driving apparatus 132 may move the support frame 134 in the major axis direction of the top plate 133 in addition to the top plate 133.

[0025] The information processing apparatus 140 includes a memory 141, a display 142, an input interface 143, and a processing circuit 144. Although the information processing apparatus 140 is described as a separate body from the gantry apparatus 110, a part of each component of the information processing apparatus 140 may be included in the gantry apparatus 110.

[0026] The memory 141 is realized by, for example, a semiconductor memory element such as a RAM (Random Access Memory) or a flash memory, a hard disk, an optical disk, or the like. The memory 141 stores, for example, projection data and CT image data. Further, for example, the memory 141 stores a program for the circuits included in the X-ray CT apparatus 101 to realize various functions. The memory 141 may be realized by a server group (cloud) connected to the X-ray CT apparatus 101 via a network.

[0027] The display 142 displays various types of information. For example, the display 142 displays various images generated by the processing circuit 144 or displays a GUI (Graphical User Interface) for receiving various operations from an operator. For example, the display 142 is a liquid crystal display or a CRT (Cathode Ray Tube) display. The display 142 may be of a desktop type or may be configured as a tablet terminal or the like capable of wireless communication with the information processing apparatus 140 main body. Further, the display 142 is an example of a display unit.

[0028] The input interface 143 receives various input operations from an operator, converts the received input operations into electrical signals, and outputs them to the processing circuit 144. Further, for example, the input interface 143 receives input operations from the operator such as scanning conditions, reconstruction conditions when reconstructing CT image data, and image processing conditions when generating a post-processing image from CT image data.

[0029] For example, the input interface 143 can be realized by a mouse, a keyboard, a trackball, a switch, a button, a joystick, a touchpad for performing an input operation by touching an operation surface, a touch screen in which a display screen and a touchpad are integrated, a non-contact input circuit using an optical sensor, a voice input circuit, or the like. Note that the input interface 143 may be provided in the gantry device 110. Further, the input interface 143 may be configured by a tablet terminal or the like that can communicate wirelessly with the information processing device 140 main body. Further, the input interface 143 is not limited to those having physical operation parts such as a mouse and a keyboard. For example, an electric signal processing circuit that receives an electric signal corresponding to an input operation from an external input device provided separately from the information processing device 140 and outputs this electric signal to the processing circuit 144 is also included in the example of the input interface 143.

[0030] The processing circuit 144 controls the operation of the entire X-ray CT apparatus 101. For example, the processing circuit 144 executes a control function 144a, a preprocessing function 144b, an acquisition function 144c, a setting function 144d, a calculation function 144e, and a correction function 144f. Here, for example, each processing function executed by the control function 144a, the preprocessing function 144b, the acquisition function 144c, the setting function 144d, the calculation function 144e, and the correction function 144f, which are components of the processing circuit 144 shown in FIG. 1, is recorded in the memory 141 in the form of a program executable by a computer. The processing circuit 144 is, for example, a processor, and reads out each program from the memory 141 and executes it to realize the function corresponding to each read program. In other words, the processing circuit 144 in the state of having read out each program has each function shown in the processing circuit 144 of FIG. 1.

[0031] The control function 144a, the preprocessing function 144b, the acquisition function 144c, the setting function 144d, the calculation function 144e, and the correction function 144f are each an example of a control unit, a preprocessing unit, an acquisition unit, a setting unit, a calculation unit, and a correction unit. Further, the control unit is an example of a display control means. Further, the memory 141 is an example of a storage unit.

[0032] In FIG. 1, the case where each processing function of the control function 144a, the preprocessing function 144b, the acquisition function 144c, the setting function 144d, the calculation function 144e, and the correction function 144f is realized by a single processing circuit 144 is shown, but the embodiment is not limited to this. For example, the processing circuit 144 may be configured by combining a plurality of independent processors, and each processor may realize each processing function by executing each program. Further, each processing function included in the processing circuit 144 may be appropriately distributed or integrated into a single or a plurality of processing circuits and realized.

[0033] The control function 144a controls various processes based on an input operation received from an operator via the input interface 143. Specifically, the control function 144a controls the CT scan performed by the gantry device 110. For example, the control function 144a controls the operations of the X-ray high voltage device 114, the X-ray detector 112, the control device 115, the DAS 118, and the bed driving device 132 to control the collection process of the count results in the gantry device 110. Taking an example, the control function 144a controls the collection process of projection data in the positioning scan for collecting the positioning image (scanogram) and the imaging (main scan) for collecting the image used for diagnosis, respectively.

[0034] Further, the control function 144a causes the display 142 to display an image or the like based on various image data stored in the memory 141 as display control means.

[0035] The preprocessing function 144b generates projection data by performing preprocessing such as logarithmic conversion processing, offset correction processing, sensitivity correction processing between channels, beam hardening correction, scattered ray correction, and dark count correction on the detection data output from the DAS 118.

[0036] The processing circuit 144 acquires various data from the X-ray detector 112 by the acquisition function 144c. The details of each function of the setting function 144d, the calculation function 144e, and the correction function 144f will be described later.

[0037] Based on such a background, the information processing apparatus according to the embodiment includes an acquisition unit, a setting unit, a calculation unit, and a correction unit. The acquisition unit acquires a structure from a medical image. The setting unit sets a line or a plane that divides the structure into a plurality of regions. The calculation unit calculates a feature amount related to the form of the structure for each of the plurality of regions. The correction unit corrects the structure so that the difference in the feature amount becomes small.

[0038] Further, the information processing method according to the embodiment acquires a structure from a medical image, sets a line or a plane that divides the structure into a plurality of regions, calculates a feature amount related to the form of the structure for each of the plurality of regions, and corrects the structure so that the difference in the feature amount becomes small.

[0039] Further, the program according to the embodiment causes a computer to execute a process of acquiring a structure from a medical image, setting a line or a plane that divides the structure into a plurality of regions, calculating a feature amount related to the form of the structure for each of the plurality of regions, and correcting the structure so that the difference in the feature amount becomes small.

[0040] That is, the information processing apparatus according to the embodiment performs correction processing so that the difference in the feature amount at each corresponding position with respect to a reference plane or the like that divides the structure acquired from the medical image becomes small. Note that the corresponding positions are, for example, symmetric positions, and the feature amount is, for example, the length of an organ. Thereby, it is possible to perform correction processing that reflects the left-right symmetry of an organ or the like while maintaining the anatomical feature amount in a proper form.

[0041] Subsequently, the processing performed by the information processing apparatus 140 according to the embodiment will be described with reference to FIGS. 2 to 13 as appropriate, using FIG. 2.

[0042] First, in step S110, the processing circuit 144 acquires, by means of the acquisition function 144c, an X-ray CT image of a subject as a medical image from the X-ray CT apparatus 101 or an in-hospital image database connected to the information processing apparatus 140. As an example of the start condition of step S110, the processing circuit 144 may acquire a CT image of a subject as the medical image by means of the acquisition function 144c triggered by receiving an instruction from a user by the processing circuit 144.

[0043] Also, as another example, when the processing circuit 144 or another processing circuit monitors a storage device for medical images such as a PACS and detects that a new image has been stored in the storage device for medical images, the processing circuit 144 may start the processing of step S110.

[0044] Also, as another example, the processing circuit 144 determines whether the new image satisfies predetermined conditions, and if the determined conditions are satisfied, the processing circuit 144 may start the processing of step S110. Examples of the determined conditions include conditions related to an imaging protocol, such as a condition that the new image was taken by an imaging protocol targeting the heart, and conditions related to a reconstruction method, such as a condition that the new image is an image reconstructed by magnification.

[0045] Note that the medical image acquired by the processing circuit 144 in step S110 is not limited to an X-ray CT image, and may be another type of image in which morphological information of the three-dimensional anatomical structure of the target living tissue is stored. As an example, the medical image acquired by the processing circuit 144 in step S110 may be an ultrasonic image, an MRI image, an X-ray image, a PET image, a SPECT image, or a four-dimensional image obtained by imaging a plurality of them in the time direction.

[0046] Subsequently, in step S120, the processing circuit 144 extracts the target structure by means of the acquisition function 144c. That is, the processing circuit 144 acquires a predetermined structure from the medical image acquired in step S110 by means of the acquisition function 144c. For example, the processing circuit 144 acquires, by means of the acquisition function 144c, the shape information of an organ included in the medical image as a predetermined structure. That is, the processing circuit 144 extracts, by means of the acquisition function 144c, a region indicating the target organ from the CT image acquired in step S110 as a predetermined structure.

[0047] For example, the processing circuit 144 extracts the region of the mitral valve by means of the acquisition function 144c and acquires the coordinate information of the pixels in the region of the mitral valve. In step S120, the processing circuit 144 may extract a predetermined structure by receiving, by means of the acquisition function 144c, a manual designation of the position of the target structure using the user interface, or may automatically extract the predetermined structure using a known region extraction technique. Examples of such region extraction techniques include, for example, Otsu's binarization method based on CT values, region growing method, snake method, graph cut method, mean shift method, and the like.

[0048] Note that the example of the extraction of the predetermined structure in step S120 is not limited to the above-described method. The processing circuit 144 may extract and acquire the predetermined structure from a shape model constructed by learning learning data prepared in advance using a machine learning technique including deep learning by means of the acquisition function 144c.

[0049] Also, as another example, the processing circuit 144 extracts, by means of the acquisition function 144c, a related region that is larger than the region of the target organ but smaller than the region of the entire image acquired in step S110, and the above-described method may be used for the related region. Thereby, the computational cost required in step S120 can be reduced.

[0050] As an example, when obtaining the mitral valve with a predetermined structure, the processing circuit 144 extracts the cardiac region as a related region by the obtaining function 144c, and obtains a predetermined structure using a known region extraction technique or the like for the related region. Further, as another example, the processing circuit 144 may extract, as a related region, for example, the union region of the left atrium region and the right atrium region by the obtaining function 144c, and obtain a predetermined structure using a known region extraction technique or the like for the related region. Note that when setting the related region, the processing circuit 144 may set the related region by receiving an input from the user using the user interface by the obtaining function 144c.

[0051] In addition, the region indicating the target organ may be separately specified for each region having different features and characteristics within the region. As an example, in the case of extracting the mitral valve, since the mitral valve is composed of two valve leaflets, a front leaflet and a rear leaflet, the processing circuit 144 may use a known region extraction technique or the like for each of the front leaflet region and the rear leaflet region as the plurality of regions by the obtaining function 144c to obtain a predetermined structure.

[0052] FIG. 3 shows an example of a predetermined structure of the mitral valve region extracted by the processing circuit 144 by the obtaining function 144c in step S120. Here, arrow 60 indicates the front leaflet portion, and arrow 61 indicates the rear leaflet portion. Further, arrow 62 represents the annulus portion, which is the outermost part in the mitral valve region, and arrow 63 represents the tip portion, which is the innermost part in the mitral valve region. Further, arrow 64 represents the anterior commissure, and arrow 65 represents the posterior commissure.

[0053] In the example of FIG. 3, the processing circuit 144 will be described as extracting the mitral valve region as a mesh represented by a lattice point group of 19 columns and 9 rows for the front leaflet region and a lattice point group of 25 columns and 9 rows for the rear leaflet region. When expressing the position of each lattice point as an identifier (x, y) where the number of rows is x and the number of columns is y as in FIG. 3, (8, 0) indicates the anterior commissure, and (8, 18) indicates the posterior commissure. Further, the outermost part in the front leaflet portion and the rear leaflet portion, that is, the position where x = 0 is called the annulus portion, and the innermost part, that is, the position where x = 8 is called the tip portion.

[0054] Note that FIG. 3 is merely an example of a predetermined structure extracted by the acquisition function 144c in the processing circuit 144 in step S120, and the number of lattice points, the arrangement, the form of the array, etc. may be different from the example shown in FIG. 3. Further, the processing circuit 144 may extract the mitral valve region not as a mesh represented by the above-described lattice point group, but as a three-dimensional image represented by a set of corresponding pixels.

[0055] Subsequently, in step S130, the processing circuit 144 sets, by the setting function 144d, a line or a plane for dividing the structure acquired from the medical image in step S120 into a plurality of regions. For example, the processing circuit 144 sets, by the setting function 144d, an axis serving as a reference for the left-right symmetry of the organ as a line or a plane for dividing the structure acquired from the medical image in step S120 into a plurality of regions. As an example, as shown in FIG. 4, the processing circuit 144 sets, by the setting function 144d, a reference line 20 for dividing the structure of the mitral valve region acquired from the X-ray CT image in step 120 into two regions. Further, when the structure acquired in step S120 is three-dimensional data instead of two-dimensional data, a reference plane instead of a reference line divides the structure acquired from the medical image in step S120.

[0056] Here, as a method for setting the reference line 20, the processing circuit 144 receives, through the setting function 144d and the input interface 143, an input of the position of the reference line 20, and sets the reference line 20 based on the received input. As an example, the processing circuit 144 receives, through the setting function 144d and the input interface 143, "y = 10" as the position of the reference line 20. As a result, the processing circuit 144 sets, through the setting function 144d, a straight line connecting the lattice point coordinates (0, 10) and (8, 10) as the reference line 20. Also, as another example, the processing circuit 144 may receive, through the setting function 144d and the user interface displayed on the display 142, a selection of a plurality of lattice points from the lattice point group of the mesh from the user, and set the reference line 20 based on the selected plurality of lattice points. At this time, as a possible user interface, the processing circuit 144 may receive, through the setting function 144d, an input of a lattice point, for example, by the user clicking on the lattice point displayed on the display 142 with a mouse, or may receive an input of a lattice point by the user inputting an identifier of the lattice point with a keyboard.

[0057] Also, as another example of the method for setting the reference line 20, the processing circuit 144 may set, through the setting function 144d, a lattice point at a predetermined position as the reference line 20. As an example, the processing circuit 144 sets, through the setting function 144d, a line connecting lattice points at the position of y = 10 in the anterior cusp region, for example, as the reference line 20.

[0058] Note that in the above example, the case where the processing circuit 144 sets, through the setting function 144d, the left - right symmetry axis of the entire organ as the reference line 20 has been described. However, the embodiment is not limited to this, and the processing circuit 144 may set, through the setting function 144d, a line other than the left - right symmetry axis of the entire organ as the reference line 20. As an example, as shown in FIG. 5, the processing circuit 144 sets, through the setting function 144d, a line connecting the point 41, which is the position of the 1 / 4 quantile of the annulus part of the anterior cusp region, and the point 42, which is the position of the 1 / 4 quantile of the cusp tip part, along the curved surface indicating the anterior cusp region, as the reference line.

[0059] As another example, the processing circuit 144 may set, by the setting function 144d, a plane passing through three predetermined points as a reference plane. As an example, the processing circuit 144 may set, by the setting function 144d, a plane passing through three points, i.e., the position of the midpoint of the valve ring portion in the anterior cusp region, the position of the midpoint of the valve tip portion in the anterior cusp region, and the midpoint of the straight line connecting the anterior commissure and the posterior commissure, as the reference plane.

[0060] Also, in the above example, the case where the processing circuit 144 sets, by the setting function 144d, a reference line for dividing a part of the mitral valve region, i.e., the anterior cusp region, into two regions has been described. However, the embodiment is not limited thereto. The processing circuit 144 may set, by the setting function 144d, a reference line for dividing the entire mitral valve region, or the posterior cusp region of the mitral valve region, or a partial region obtained by other division methods of the mitral valve region into two regions.

[0061] Also, in the above example, the case where the processing circuit 144 sets, by the setting function 144d, a reference line or a reference plane for dividing the structure acquired from the medical image in step S120 into two regions has been described. However, the embodiment is not limited thereto. For example, the processing circuit 144 may set, by the setting function 144d, a reference line or a reference plane for dividing the structure acquired from the medical image in step S120 into three or more regions. As an example, the processing circuit 144 may set, by the setting function 144d, a line connecting the position of the point at the 1 / 3 quantile of the valve ring portion and the position of the point at the 1 / 3 quantile of the valve tip portion in the anterior cusp region of the mitral valve along the curved surface indicating the anterior cusp region as the first reference line, and a line connecting the position of the point at the 2 / 3 quantile of the valve ring portion and the position of the point at the 2 / 3 quantile of the valve tip portion in the anterior cusp region of the mitral valve along the curved surface indicating the anterior cusp region as the second reference line.

[0062] Subsequently, in step S140, the processing circuit 144 sets correction locations based on the predetermined structure extracted in step S120 by the setting function 144d. Such a situation is shown in FIG. 6. In step S140, the processing circuit 144 sets a set of lines or planes that are correction locations based on the reference line 20 set in step S130 by the setting function 144d. In the case of FIG. 6, the processing circuit 144 sets a set of broken lines that are correction locations based on the reference line 20 set in step S130 by the setting function 144d. As another example, the processing circuit 144 may set a set of line segments that are correction locations based on the reference line 20 set in step S130 by the setting function 144d.

[0063] The processing circuit 144 calculates feature amounts at corresponding locations with respect to the reference line 20 which is, for example, the axis serving as the reference for the left-right symmetry of the organ and is set in step S130, by the setting function 144d. Specifically, the processing circuit 144 sets, as a set of lines that are correction locations, a set of line segments at positions symmetric with respect to the reference line 20 set in step S130 by the setting function 144d. As an example, the processing circuit 144 sets, as a set of lines that are correction locations, line segment 21 and line segment 22 having substantially equal distances from the reference line 20 by the setting function 144d. Similarly, the processing circuit 144 sets, as a set of lines that are correction locations, line segment 23 and line segment 24 having substantially equal distances from the reference line 20 by the setting function 144d. Similarly, the processing circuit 144 sets, as a set of lines that are correction locations, line segment 25 and line segment 26 having substantially equal distances from the reference line 20 by the setting function 144d.

[0064] In the above example, the number of sets of lines that are correction locations is three sets and the case of a plurality of sets has been described, but the number of sets of lines that are correction locations is not limited to this, and for example, the number of sets of lines that are correction locations may be one set.

[0065] In the above example, the shape of the correction location is described as a line segment. However, the embodiment is not limited to the case where the shape of the correction location is one-dimensional, and the shape of the correction location may be a two-dimensional closed curve, a three-dimensional region, or a zero-dimensional point. FIG. 7 shows the case where the shape of the correction location is a two-dimensional closed curve.

[0066] In this case, the processing circuit 144 sets, by the setting function 144d, a pair of closed curves 30 and 31, which is a pair of closed curves at positions symmetric with respect to the reference line 20 set in step S130, as a pair of closed curves for the correction location. Similarly, the processing circuit 144 sets, by the setting function 144d, a pair of closed curves 32 and 33, and a pair of closed curves 34 and 35, which are pairs of closed curves at positions symmetric with respect to the reference line 20 set in step S130, as pairs of closed curves for the correction location.

[0067] Note that the setting of the correction location in step S140 may be automatically set by the processing circuit 144 by the setting function 144d according to a predetermined criterion, or the processing circuit 144 may set the correction location by the setting function 144d by receiving an input of the correction location from the user through the user interface.

[0068] Instead of receiving an input of the correction location from the user, the processing circuit 144 may receive an input of the range of the correction location from the user by the setting function 144d. For example, in FIG. 6, when the processing circuit 144 receives an input of the range 27 of the correction location from the user through the user interface by the setting function 144d, the processing circuit 144 sets, by the setting function 144d, a pair of line segments 21 and 22, a pair of line segments 23 and 24, and a pair of line segments 25 and 26, which are line segments included in the range 27 of the correction location, as a pair of lines for the correction location.

[0069] If the range 27 of the correction location received from the user through the user interface by the setting function 144d of the processing circuit 144 is inappropriate, the processing circuit 144 may not be able to set the set of lines to be the correction location within the range 27 of the correction location by the setting function 144d. In such a case, the processing circuit 144 may display that fact to the user and request the user to re-enter the range 27 of the correction location, or alternatively, the processing circuit 144 may set, by the setting function 144d, the set of lines that is closest to the given conditions as the set of lines to be the correction location. In this way, the processing circuit 144 sets the correction location from the structure based on the line or surface by the setting function 144d.

[0070] Subsequently, in step S150, the processing circuit 144 sets an evaluation value used as a reference when correcting the correction location set in step S140 by the setting function 144d. As an example, the processing circuit 144 determines, by the setting function 144d, what feature amount to be based on when correcting the correction location set in step S140. As an example, when the type of the correction location set in step S140 is a line, the feature amount used as a basis when performing the correction is the length of the line. As an example, the processing circuit 144 uses, by the setting function 144d, the length of the organ measured along the direction of the axis, which is the reference line set in step S130, as a feature amount when correcting the correction location set in step S140, and performs the correction based on the feature amount by the correction function 144f.

[0071] Also, as another example, the feature amount used as a basis when performing the correction may be an angle. As an example, the processing circuit 144 performs the correction using, as a feature amount, the angle formed with a reference plane or reference line obtained from, for example, the structure of the valve tip portion when correcting the correction location set in step S140 by the setting function 144d.

[0072] Also, when the type of the correction location set in step S140 is a closed curve, the original feature amounts when performing correction are, for example, the perimeter, area, circularity, etc. For example, when correcting the correction location set in step S140, the processing circuit 144 performs correction using, as a feature amount, for example, the area or perimeter of the closed curve, etc., by the setting function 144d.

[0073] Also, when the type of the correction location set in step S140 is a three-dimensional region, the volume, surface area, sphericity, etc. become the feature amounts. In this case, when correcting the correction location set in step S140, the processing circuit 144 performs correction using, as a feature amount, for example, the volume, surface area, sphericity, etc., by the setting function 144d.

[0074] The setting of the feature amount serving as the correction reference set in step S140 may be performed by the processing circuit 144 manually receiving an input from the user through the user interface by the setting function 144d. As another example, conditions may be set in advance so that the feature amount serving as the correction reference is automatically set. Also, the feature amount serving as the correction reference may be automatically determined according to the type of the correction location set in step S140.

[0075] In the embodiment, the case where the process of step S150 is performed after the process of step S140 has been described, but the embodiment is not limited to this, and the process of step S140 may be performed after the process of step S150 has been performed. In this case, options that are incompatible with the correction reference selected by the user in step S150 may be excluded in the process of step S140.

[0076] Subsequently, in step S160, the processing circuit 144 corrects the correction location set in step S140 based on the correction reference set in step S150 by the correction function 144f.

[0077] Regarding the process of step S160, with reference to FIGS. 8 to 11, when the type of the correction location set in step S140 is a line segment and the feature quantity serving as the correction reference set in step S150 is the length of the organ measured along the reference line 20, it will be described. Here, FIGS. 8 to 11 illustrate the process when the processing circuit 144 performs correction by the correction function 144f on the line segments 21 and 22 at positions corresponding to the reference line 20 in FIG. 6 as the correction targets.

[0078] Here, FIG. 8 shows the line segments 21 and 22 before correction. The grid points 10a, 10b, 10c, 10d, 10e, 10f, 10g, 10h are the grid points of the line segment 21, and the grid points 11a, 11b, 11c, 11d, 11e, 11f, 11g, 11h are the grid points of the line segment 22. Each of the grid points 10a to 10h and 11a to 11h corresponds to the grid points in the mesh of FIG. 6. That is, in FIG. 8, the organ included in the medical image acquired in step S110 is a heart valve, and the processing circuit 144 uses a plurality of line segments 21 to 26 extending from the cusp direction to the annulus direction to represent the target structure acquired from the medical image in steps S120 to S140 by the setting function 144d. Here, each of the plurality of line segments 21 to 26 is obtained by connecting line segments formed by connecting a plurality of grid points such as the grid points 10a to 10h and 11a to 11h.

[0079] First, the processing circuit 144 calculates, by the calculation function 144e, the feature quantity regarding the form of the structure acquired from the medical image in step S110 for each of the plurality of regions. In the case of FIG. 8, the processing circuit 144 calculates, by the calculation function 144e, for example, the length of the line segment 21, which is the length of the organ measured along the reference line 20, and the length of the line segment 22, which is the length of the organ measured along the reference line 20, for each of the line segment 21 located in the region to the left of the reference line 20 and the line segment 22 located in the region to the right of the reference line 20.

[0080] Note that the feature amount of the embodiment is not limited to the length of the line segment measured along the reference line 20. For example, the processing circuit 144 may calculate the lengths of the line segment 21 and the line segment 22 themselves as feature amounts by the calculation function 144e.

[0081] Also, as another example, the processing circuit 144 may calculate the lengths of the broken lines constituting the line segments 21 and 22 by the calculation function 144e, and calculate the average value, median value, minimum value, or maximum value of the lengths of those broken lines as feature amounts. In this way, the processing circuit 144 calculates the feature amounts for the correction locations set by the setting function 144d by the calculation function 144e.

[0082] Subsequently, the processing circuit 144 corrects the structure acquired from the medical image in step S110 by the correction function 144f so that the difference in the calculated feature amounts becomes small. As an example, the processing circuit 144 corrects the structure acquired from the medical image in step S110 by the correction function 144f so that the difference in the feature amounts calculated for each corresponding location becomes small.

[0083] An example of such processing is shown in FIG. 9. FIG. 9 is a diagram showing an example of correction processing performed by the processing circuit 144 by the correction function 144f. Here, the lattice points 10a and 11a indicate the lattice points before the correction processing, and the lattice points 12a and 12b indicate the lattice points after the correction processing. The processing circuit 144 corrects the structure obtained from the medical image by correcting the positions of the lattice points on the valve ring side among the plurality of lattice points for each of the plurality of line segments 21 to 26 by the correction function 144f. For example, the processing circuit 14 corrects the structure obtained from the medical image by correcting the positions of the lattice points 10a and 11a on the valve ring side among the lattice points 10a to 10h and 11a to 11h to the positions of the lattice points 12a and 13a, respectively, for each of the line segments 21 and 22 by the correction function 144f. As an example, the processing circuit 144 corrects the positions of the lattice points 10a and 11a on the valve ring side to the positions of the lattice points 12a and 13a, respectively, by the correction function 144f so that the lengths of the corrected line segments 21 and 22 become the average value of the length of the line segment 21 before the correction and the length of the line segment 22 before the correction.

[0084] In this way, by moving only the end points on the valve ring side, the processing circuit 144 according to the embodiment can correct the valve length to be symmetric without changing the valve orifice shape.

[0085] Note that, in a case where it is not desired to change the end points on the valve ring side, etc., the processing circuit 144 may correct only the lattice points on the valve tip side instead of the lattice points on the valve ring side by the correction function 144f. Further, the processing circuit 144 may correct both the lattice points on the valve ring side and the lattice points on the valve tip side by the correction function 144f.

[0086] Note that the method of correction processing performed by the processing circuit 144 using the correction function 144f is not limited to the above example, and various methods are conceivable. As an example, for instance, the processing circuit 144, using the correction function 144f, identifies lattice points 12a and 13a at positions where the length of the corrected line segment 21 becomes the length of the line segment 22 before correction, and the length of the corrected line segment 22 becomes the length of the line segment 21 before correction, respectively, and corrects the positions of lattice points 10a and 11a so as to be the midpoints between 10a and 12a and between 11a and 13a. Further, the processing circuit 144 calculates the lengths of the broken lines constituting the line segments 21 and 22, calculates, as feature amounts, the average value, median value, minimum value, or maximum value, etc. of the lengths of those broken lines, and performs correction processing so that, for example, the average value of the lengths of the broken lines, etc. respectively matches the length between the corrected lattice point 10b and the lattice point 12a, and the length between the corrected lattice point 11b. Thus, the processing circuit 144 corrects the structure using the correction function 144f with length, angle, perimeter, or area, etc. as the correction reference.

[0087] Also, as an optional component, the processing circuit 144 according to the embodiment may further perform the additional processing shown in FIG. 10 or FIG. 11 to correct the line segments 21 and 22. For example, the processing circuit 144, using the correction function 144f, performs rearrangement of the lattice points as shown in FIG. 10 and updates the positions of a plurality of lattice points based on the corrected lattice points 12a and 13a shown in FIG. 9 and the lattice points 10b to 10h and 11b to 11h before correction shown in FIG. 9. For example, the processing circuit 144, using the correction function 144f, performs rearrangement of the lattice points so that the distances between these lattice points become equally spaced based on the corrected lattice point 12a, etc. and the lattice points 10b to 10h before correction, updates the positions of a plurality of lattice points, and generates the rearranged lattice points 12a, 12b, 12c, etc. Further, the processing circuit 144, using the correction function 144f, performs rearrangement of the lattice points so that the distances between these lattice points become equally spaced based on the corrected lattice point 13a and the lattice points 11b to 10h before correction, updates the positions of a plurality of lattice points, and generates the rearranged lattice points 13a, 13b, 13c, etc.

[0088] In this way, by rearranging the lattice points so that the distances between the lattice points are equally spaced, it may become easier to perform processing in cases such as when performing some post-processing such as calculating measured values.

[0089] Also, as an optional component, for example, as shown in FIG. 11, the processing circuit 144 performs weighted addition between the positions of a plurality of updated lattice points 12a to 12c, etc. and the positions of a plurality of lattice points 10a to 10c, etc. before update by the correction function 144f, thereby further updating the positions of the plurality of lattice points to generate a plurality of lattice points 14a to 14c, and correcting the target structure extracted from the medical image in step S120. As an example, the processing circuit 144 takes the midpoints between the positions of a plurality of updated lattice points 12a to 12c, etc. and the positions of a plurality of lattice points 10a to 10c, etc. before update by the correction function 144f respectively, thereby further updating the positions of the plurality of lattice points to generate a plurality of lattice points 14a to 14c. Thereby, the target structure extracted from the medical image in step S120 is corrected. Similarly, the processing circuit 144 performs weighted addition between the positions of a plurality of updated lattice points 13a to 13c, etc. and the positions of a plurality of lattice points 11a to 11c, etc. before update by the correction function 144f. Thereby, the positions of the plurality of lattice points are further updated to generate a plurality of lattice points 15a to 15c, and the target structure extracted from the medical image in step S120 is corrected.

[0090] Also, as a further optional component, the processing circuit 144 may perform the rearrangement of the lattice points shown in FIG. 10 on the plurality of lattice points obtained by the procedure shown in FIG. 11 by the correction function 144f so that the lattice points are equally spaced.

[0091] Also, as a further optional component, the processing circuit 144 may correct the structure extracted from the medical image by repeating a plurality of times a series of steps shown in FIGS. 8 to 11 or steps obtained by adding a step of performing the rearrangement of the lattice points shown in FIG. 10 after a series of steps shown in FIGS. 8 to 11.

[0092] In the process shown in FIG. 9, as a method for correcting the lattice points 10a and 11a on the valve ring side, the case where the lattice points 10a and 11a on the valve ring side are corrected based on the average value of the line segment 21 and the line segment 22 has been described. However, as described above, in the embodiment, for example, the lattice point 10a on the valve ring side of the line segment 21 is corrected based on the length of the line segment 22 before correction, and the lattice point 11a on the valve ring side of the line segment 22 is corrected based on the length of the line segment 21 before correction. Various methods are possible. The processing circuit 144 according to the embodiment can also execute the steps in FIGS. 8 to 11 after replacing the step in FIG. 9 with the various methods described above.

[0093] Next, the correction process in step S160 when the feature amount serving as the correction reference set in step S150 is an angle will be described with reference to FIG. 12. FIG. 12 is a diagram for explaining the correction process in step S160 when the feature amount serving as the correction reference set in step S150 is an angle. The processing circuit 144 corrects the structure extracted from the medical image based on the angle formed by the reference plane or reference line obtained from the structure of the valve tip portion and each line segment by the correction function 144f. In FIG. 12, the processing circuit 144 corrects the line segments 25 and 26 shown in FIG. 6 by the correction function 144f. That is, FIG. 12 corresponds to a view of the three-dimensional structure shown in FIG. 6 as seen from the horizontal direction of the screen. Here, the straight line 72 indicates the reference plane or reference line obtained from the structure of the valve tip portion, specifically, the least-squares plane of the closed curve formed by the valve tip portion.

[0094] First, the processing circuit 144 calculates, by the correction function 144f, the angle 70 formed by the line segment 25 and the straight line 72, which is the reference plane or reference line obtained from the structure of the valve tip portion.

[0095] Here, a method for calculating the angle formed by a line segment and a reference plane or reference line will be described. For example, when the line segment 25 intersects the straight line 72, the processing circuit 144 calculates, by means of the correction function 144f, the angle formed by the line segment 25 and the straight line 72 at the intersection of the line segment 25 and the straight line 72 as the angle 70 formed by the line segment 25 and the straight line 72. On the other hand, for example, when the line segment 25 and the straight line 72 do not have an intersection point, the processing circuit 144 calculates, by means of the correction function 14f, the angle formed by the straight line obtained by extrapolating the line segment 25 and the straight line 72 at the intersection point of the straight line obtained by extrapolating the line segment 25 and the straight line 72 as the angle 70 formed by the line segment 25 and the straight line 72.

[0096] As another example of the method for calculating the angle formed by a line segment and a reference plane or reference line, the processing circuit 144 may calculate, by means of the correction function 144f, an approximate straight line of the line segment 25 by the least squares method, and calculate the angle formed by the approximate straight line and the straight line 72 as the angle formed by the line segment and the reference plane or reference line.

[0097] Similarly, the processing circuit 144 calculates the angle 71 formed by the line segment 26 and the straight line 72 by means of the correction function 144f.

[0098] Subsequently, the processing circuit 144 corrects the position of the grid point by means of the correction function 144f so that the angle 70 formed by the line segment 25 and the straight line 72 coincides with the angle 71 formed by the line segment 26 and the straight line 72. As an example, the processing circuit 144 corrects the position of the grid point 17 at the tip of the valve of the line segment 26 to the position of the grid point 18 by means of the correction function 144f so that the angle formed by the corrected line segment 26 and the straight line 72 coincides with the angle 70 which is the angle formed by the line segment 25 and the straight line 72. At this time, the processing circuit 144 parallel-translates the position of the grid point 17 in the direction parallel to the straight line 72 to correct it to the position of the grid point 18.

[0099] Note that the processing circuit 144 may align the smaller angle with the larger angle among the angle 70 and the angle 71 by the correction function 144f, or may align the larger angle with the smaller angle. Also, as another example, the processing circuit 144 may correct the line segment 25 and the line segment 26 by the correction function 144f so that the angle formed with the corrected straight line 72 is the average angle of the angle 70 and the angle 71.

[0100] Next, the correction process in step S160 when the correction location set in step S140 is a closed curve and the feature quantity serving as the correction reference set in step S150 is the perimeter or the area will be described with reference to FIG. 13.

[0101] FIG. 13 is a diagram for explaining the correction process in step S160 when the feature quantity serving as the correction reference set in step S150 is the perimeter or the area. Specifically, FIG. 13 shows a case where the processing circuit 144 performs a correction process on the closed curve 31 in FIG. 7 by the correction function 144f. Here, the grid points 51, 52, 55, 56, etc. in FIG. 13 are grid points on the closed curve 31.

[0102] Here, the processing circuit 144 calculates the centroid 50 of the closed curve 31 by the correction function 144f. Subsequently, the processing circuit 144 adjusts, by the correction function 144f, the distances from the centroid 50 of, for example, the grid point 51 and the grid point 52, and corrects the closed curve 31 by, for example, adjusting the grid point 51 to the grid point 53 and the grid point 52 to the grid point 54. As an example, the processing circuit 144 corrects the positions of the grid point 51 and the grid point 52 included in the closed curve 31 to the grid point 53 and the grid point 54, respectively, so that the perimeter or the area of the corrected closed curve 31 is equal to the perimeter or the area of the closed curve 30.

[0103] Subsequently, in step S170, the processing circuit 144 determines, by a determination function (not shown), whether the correction of all the correction points set by the setting function 144d in step S140 has been completed. If the correction process has been performed for all the correction points set in step S140 (step S170 Yes), the correction process ends. On the other hand, if there is a location where the correction process has not been performed (step S170 No), the process returns to step S160, and the processing circuit 144 executes the correction process of step S160 for the set of correction points for which the correction has not been completed by the correction function 144f.

[0104] Note that the processing circuit 144 usually performs the same type of correction process for all the correction points set in step S140 by the correction function 144f, but the embodiment is not limited to this. The processing circuit 144 may change the processing of the correction method according to the correction points set in step S140 by the correction function 144f. As an example, the processing circuit 144 may change the method of the correction process executed in step S160 according to the distance from the reference line 20 set in step S130 by the correction function 144f.

[0105] Further, the embodiment is not limited to performing correction processing on all correction target locations. Instead, correction processing may be performed only on some of the correction locations set in step S140. As an example, the processing circuit 144 may further perform a process of determining whether to perform correction processing on each set of correction locations in the process of step S170. Also, as an example, for the set of correction locations set in step S140, the processing circuit 144 first calculates the correction reference in step S160 by the calculation function 144e. If the difference in the correction reference for the set of correction locations is equal to or less than a threshold value, correction processing may not be performed on the correction location in step S160. Also, the threshold value may be set in advance, or may be set by receiving user input from the user interface. Also, as another example, in step S140 or step S150, the processing circuit 144 calculates the difference in the correction reference by the correction function 144f, and sets the sets with a difference in the correction reference equal to or less than the threshold value as not being correction locations in step S160.

[0106] As described above, in the first embodiment, the processing circuit 440 sets a line or a plane that divides the structure acquired from the medical image by the setting function 144d, and calculates, by the calculation function 144e, a feature amount related to the form of the structure for each of a plurality of regions, and corrects the structure so that the difference in the feature amount becomes small. As an example, the processing circuit 440 performs correction processing so that corresponding feature amounts, such as the length of an organ, match at corresponding positions, such as symmetric positions, with respect to a reference plane that divides the structure acquired from the medical image. Thereby, correction processing that reflects the left-right symmetry of the organ or the like can be performed while maintaining the anatomical feature amount in a proper form.

[0107] (First Modification Example of the First Embodiment) In the first embodiment, the processing circuit 144 sets lines or surfaces that divide the structure obtained from the medical image into a plurality of regions by means of the setting function 144d, calculates feature amounts regarding the form of the structure for each of the plurality of regions by means of the calculation function 144e, and corrects the structure by means of the correction function 144f so that the difference in the feature amounts becomes small. However, the embodiment is not limited to this, and the processing circuit 144 may calculate an evaluation value based on the form and shape of the structure by means of the calculation function 144e, and select a method for correcting the structure based on the calculated evaluation value by means of the correction function 144f.

[0108] The form and shape referred to here are, for example, curvature. That is, the processing circuit 144 may calculate the curvature as an evaluation value for each of the plurality of divided regions by means of the correction function 144f, and select a method for correcting the structure based on the calculated evaluation value. As an example, when the curvature is large, there is a possibility that the reliability of the process in which the processing circuit 144 acquires the structure by means of the acquisition function 144c in step S120 is low. In this case, in step S160, for example, the processing circuit 144, by means of the correction function 144f, corrects the structure with a higher curvature according to the structure with a lower curvature among the sets set for the correction locations in step S140. That is, when the curvature of the first correction location is greater than the curvature of the second correction location among the sets set for the correction locations in step S140, the processing circuit 144, by means of the correction function 144f, selects a method for correcting the first correction location according to the second correction location, and when the curvature of the first correction location is less than the curvature of the second correction location, selects a method for correcting the second correction location according to the first correction location. In other words, the processing circuit 144, by means of the correction function 144f, selects a method for correcting the structure according to the reliability of the process for acquiring the structure.

[0109] Also, as another example, when the difference in shape between the correction points of the same set is large compared to another set set at the correction point in step S140, the reliability of the process of obtaining the structure in step S120 in that set may be low. Therefore, the processing circuit 144 may correct the correction points of the set with a large difference in shape between the correction points according to the correction points of the set with a small difference in shape between the correction points by the correction function 144f.

[0110] Also, as another example, when performing the process of step S120 for each of the plurality of divided regions, the processing circuit 144, by the calculation function 144e, calculates, for each pixel, the likelihood of the structure obtained from the medical image for that pixel, that is, the probability that the pixel is the said structure, as an evaluation value, and may select a method of correcting the said structure based on the calculated evaluation value by the correction function 144f. Here, the processing circuit 144 calculates the likelihood using, for example, U-Net by the calculation function 144e. It is considered that a correction point with more pixels having a high likelihood among the sets set at the correction point is more reliable than the other correction point containing more pixels with a low likelihood. Therefore, the processing circuit 144 corrects the other correction point according to the correction point with more pixels having a high likelihood by the correction function 144f.

[0111] As described above, in the first modification of the first embodiment, the processing circuit 144 calculates an evaluation value or the like, and further changes the method of the correction process based on the calculated evaluation value or the like. Thereby, the accuracy of the correction process is further improved.

[0112] (Second modification of the first embodiment) In the second modification of the first embodiment, a user interface for displaying the corrected image to the user will be described. FIG. 14 shows an example of such a user interface. When the correction of all correction points is completed in step S170, the processing circuit 144 causes the control function 144a to display an image 82 of the area including the corrected correction points on the display screen 80 of the display 142. Here, when the processing circuit 144 receives an instruction from the user to display in parallel the image before correction and the image after correction through the button 83 by the control function 144a, the processing circuit 144 causes the control function 144a to display the image 82 after correction on the display 142 together with the image 81 before correction. Further, when the processing circuit 144 receives an instruction from the user to superimpose the image before correction and the image after correction through the button 84 by the control function 144a, the processing circuit 144 causes the control function 144a to superimpose the image before correction and the image after correction on the display 142. That is, the processing circuit 144 causes the control function 144a to superimpose the medical image before correction and the medical image after correction on the display unit.

[0113] In addition, the processing circuit 144 causes the control function 144a to display a screen 87 for asking the user whether to accept the execution of the correction on the display 142 for the user who refers to the corrected image 82. When the processing circuit 144 receives the user's selection to accept the execution of the correction through the button 88 by the control function 144a, the processing circuit 144 accepts the image 82 after correction as a medical image on which the correction process has been correctly performed, and stores the image 82 after correction in the memory 141. On the other hand, when the processing circuit 144 receives the user's selection not to accept the execution of the correction through the button 89 by the control function 144a, the processing circuit 144 discards the image 82 after correction, ends the process, or changes the conditions and performs the correction process. In this case, the processing circuit 144 may receive the input of the changed conditions from the user by the control function 144a.

[0114] As described above, in the second modification of the first embodiment, the processing circuit 144 includes a user interface that performs processing such as displaying the corrected image to the user or receiving an input from the user. This improves the usability for the user.

[0115] (Third Modification of the First Embodiment) The embodiment is not limited to the above example. As an example, in step S160, the processing circuit 144 may calculate a feature amount or a measurement value for the corrected portion where correction has been performed by the calculation function 144e, and display the measurement value before correction and the measurement value after correction to the user. Also, as an example, as shown in FIG. 14, the processing circuit 144 causes the control function 144a to display the measurement value before correction on the display 142 as a message 85 to the user, and also causes the measurement value after correction to be displayed on the display 142 as a message 86 to the user.

[0116] Further, the processing circuit 144 causes the control function 144a to display, on the display 142, a screen 87 for asking the user whether to accept the implementation of the correction for the user who has referred to the message 86 to the user regarding the measurement value after correction. When the processing circuit 144 receives, through the button 88, the user's selection to accept the implementation of the correction by the control function 144a, the processing circuit 144 accepts the corrected image 82 as a medical image for which the correction process has been correctly performed, and stores the corrected image 82 in the memory 141. On the other hand, when the processing circuit 144 receives, through the button 89, the user's selection not to accept the implementation of the correction by the control function 144a, the processing circuit 144 discards the corrected image 82, ends the process, or changes the conditions and performs the correction process. In this case, the processing circuit 144 may receive an input of the changed conditions from the user by the control function 144a.

[0117] As described above, in the third modification of the first embodiment, the processing circuit 144 further displays the measurement value for the corrected portion where correction has been performed to the user. This improves the usability for the user.

[0118] (Fourth Modification of the First Embodiment) In the embodiments described so far, the case where the target organ is the mitral valve has been described. However, the embodiments are not limited to this. The embodiments may be organs other than the heart, such as the brain, vocal cords, uterus, etc. In these organs, since there is an axis that serves as a reference for the left - right symmetry of the organ, the processing circuit 144 divides the organ into a plurality or sets a plane by the setting function 144d. The processing circuit 144 corrects the structure by the correction function 144f so that the difference in feature amounts becomes small for each of the plurality of regions. Similar to the case of the mitral valve, as an example, the processing circuit 144 uses the correction function 144f to use the length of the organ measured along the direction of the reference axis as a feature amount for each corresponding location with respect to the reference axis, and performs correction processing so that the difference in the length of the organ measured along the direction of the reference axis at each location corresponding to the reference axis becomes small. Thereby, the processing circuit 144 can similarly perform correction processing for organs other than the heart.

[0119] According to at least one of the embodiments described above, it is possible to improve the extraction accuracy when extracting the region of a predetermined organ from a medical image and the calculation accuracy of various measurement values based on the region.

[0120] Although several 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, replacements, changes, and combinations of the embodiments can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and its equivalent scope.

Description of Reference Numerals

[0121] 140 Information processing apparatus 141 Memory 142 Display 143 Input interface 144 Processing circuit 144a Control function 144b Pretreatment function 144c Acquisition function 144d Setting function 144e Calculation function 144f Correction function

Claims

1. an acquisition unit for acquiring a structure from a medical image; A setting unit that sets a line or a surface that divides the structure into a plurality of regions; a calculation unit that calculates a feature amount related to a form of the structure for each of the plurality of regions; a correction unit that corrects the structure so that the difference in the feature amount is reduced; An information processing device comprising:

2. The acquisition unit acquires shape information of an organ included in the medical image as the structure, The information processing device according to claim 1 , wherein the setting unit sets an axis that is a reference for left-right symmetry of the organ as the line or the plane.

3. The information processing device according to claim 2 , wherein the feature amount is a length of the organ measured along the axis direction.

4. The calculation unit calculates the feature amounts at corresponding locations on the axis, The information processing device according to claim 2 , wherein the correction unit corrects the structure so that a difference between the feature amounts calculated for the corresponding locations becomes small.

5. the organ is a heart valve, the setting unit represents the structure using a plurality of line segments extending from a valve cusp direction to a valve annulus direction, and each of the plurality of line segments is obtained by connecting a plurality of lattice points to each other; The information processing device according to claim 2 , wherein the correction unit corrects the structure by modifying positions of the lattice points on a valve annulus side among the plurality of lattice points for each of the plurality of line segments.

6. The correction unit updates positions of the plurality of lattice points based on the corrected lattice points; The information processing device according to claim 5 , further comprising: a weighted addition process for calculating the positions of the plurality of lattice points after the update and the positions of the plurality of lattice points before the update, thereby correcting the structure.

7. The information processing device according to claim 1 , wherein the characteristic amount is an angle between the valve tip and a base plane or a base line obtained from a structure of the valve tip.

8. The information processing apparatus according to claim 1 , wherein the feature amount is an area or a perimeter of a closed curve.

9. The setting unit sets a correction point from the structure based on the line or the surface, The information processing apparatus according to claim 1 , wherein the calculation unit calculates the feature amount for the correction portion set by the setting unit.

10. The information processing device according to claim 1 , wherein the correction unit corrects the structure using a length, an angle, a circumference or an area as a correction standard.

11. The information processing device according to claim 1 , wherein the correction unit selects a method for correcting the structure depending on reliability of a process for acquiring the structure.

12. The information processing apparatus according to claim 1 , further comprising a display control unit that causes the medical image before the correction and the medical image after the correction to be superimposed on each other on a display unit.

13. Extracting structures from medical images; defining lines or planes dividing the structure into a plurality of regions; Calculating a feature amount relating to a morphology of the structure for each of the plurality of regions; correcting the structure so that the difference in the feature amount is reduced; Information processing methods.

14. Extracting structures from medical images; defining lines or planes dividing the structure into a plurality of regions; Calculating a feature amount relating to a morphology of the structure for each of the plurality of regions; The structure is corrected so that the difference in the feature amount is reduced. The program to be executed.

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