Mapping image display control device, method, and program
11304762 ยท 2022-04-19
Assignee
Inventors
Cpc classification
A61B5/08
HUMAN NECESSITIES
A61B6/4405
HUMAN NECESSITIES
A61B5/05
HUMAN NECESSITIES
A61B6/50
HUMAN NECESSITIES
A61B2034/104
HUMAN NECESSITIES
A61B34/10
HUMAN NECESSITIES
G06T19/20
PHYSICS
A61B34/20
HUMAN NECESSITIES
A61B5/4887
HUMAN NECESSITIES
A61B6/5217
HUMAN NECESSITIES
A61B5/004
HUMAN NECESSITIES
G06T7/187
PHYSICS
International classification
A61B34/00
HUMAN NECESSITIES
A61B5/05
HUMAN NECESSITIES
A61B5/00
HUMAN NECESSITIES
A61B6/00
HUMAN NECESSITIES
A61B34/20
HUMAN NECESSITIES
A61B34/10
HUMAN NECESSITIES
G06T19/20
PHYSICS
A61B5/08
HUMAN NECESSITIES
G06T7/187
PHYSICS
Abstract
An arrival position information estimation unit that estimates arrival position information at which an extension line of a peripheral branch included in a bronchial region arrives at a surface of a lung region, and estimates assumed mapping information other than the arrival position information of a specific peripheral branch on the basis of a preset condition in a case where the specific peripheral branch is set as a target branch, and a display control unit that generates a mapping image obtained by mapping the arrival position information of the specific peripheral branch and the assumed mapping information to a surface of the lung region and displays the mapping image on a display unit are included.
Claims
1. A mapping image display control device comprising: a processor configured to: extract a lung region included in a three-dimensional image; extract a bronchial region included in the lung region; acquire information on a branch position of the bronchial region; estimate arrival position information at which an extension line of a specific peripheral branch included in the bronchial region as a target branch arrives at a surface of the lung region on a basis of the information on the branch position; set a condition of an erroneous insertion of a catheter inserting into a bronchus erroneously; estimate, on the basis of the condition of the erroneous insertion, assumed mapping information at which an extension line of another peripheral branch that is erroneously inserted with the catheter arrives at the surface of the lung region, the another peripheral branch being different from the specific peripheral branch and the another peripheral branch extending from a branch position that is present between a proximal end portion of the bronchial region and the specific peripheral branch, and the arrival position information and the assumed mapping information representing a point or a range at which a dye arrives when the dye is sprayed from within the bronchial region toward the specific peripheral branch; and generate a mapping image obtained by mapping the arrival position information of the specific peripheral branch and the assumed mapping information to the surface of the lung region and display the mapping image on a display.
2. The mapping image display control device according to claim 1, wherein the another peripheral branch extends from a first branch position or a second branch position from a terminal of the specific peripheral branch.
3. The mapping image display control device according to claim 1, wherein the processor is further configured to estimate a straight line set on the basis of the information on the branch position and the specific peripheral branch as the extension line of the branch.
4. The mapping image display control device according to claim 3, wherein the processor is further configured to estimate a straight line set on the basis of a terminal of the specific peripheral branch and information on a first branch position from the terminal as the extension line of the specific peripheral branch.
5. The mapping image display control device according to claim 1, wherein the processor is further configured to perform spline interpolation using a point on the specific peripheral branch and a point specified on the basis of the information on the first branch position from the terminal of the specific peripheral branch, and estimate a curve obtained by the spline interpolation as the extension line of the specific peripheral branch.
6. The mapping image display control device according to claim 1, wherein the processor is further configured to specify the specific peripheral branch on the basis of the information on the branch position, specify a dominant region of the specific peripheral branch in the lung region, and estimate a straight line connecting a center of gravity of the dominant region to a terminal of the specific peripheral branch as the extension line of the specific peripheral branch.
7. The mapping image display control device according to claim 1, wherein the processor is further configured to specify the specific peripheral branch on the basis of the information on the branch position, specify a dominant region of the specific peripheral branch in the lung region, and estimate a center of gravity of a region that is a surface of the lung region in a surface of the dominant region as the arrival position information.
8. The mapping image display control device according to claim 1, wherein the processor is further configured to extract a blood vessel region included in the lung region, and estimate the extension line of the specific peripheral branch on the basis of information on the blood vessel region and the branch position.
9. The mapping image display control device according to claim 8, wherein the processor is further configured to extract at least one of a pulmonary vein region or a pulmonary artery region as the blood vessel region.
10. The mapping image display control device according to claim 1, wherein the processor is further configured to set a region on the basis of the arrival position information of the specific peripheral branch and the assumed mapping information, generate a mapping image obtained by mapping the region on the surface of the lung region, and display the mapping image on the display.
11. A mapping image display control method comprising: extracting a lung region included in a three-dimensional image; extracting a bronchial region included in the lung region; acquiring information on a branch position of the bronchial region; estimating arrival position information at which an extension line of a specific peripheral branch included in the bronchial region as a target branch arrives at a surface of the lung region on a basis of the information on the branch position; setting a condition of an erroneous insertion of a catheter inserting into a bronchus erroneously; estimating, on the basis of the condition of the erroneous insertion, assumed mapping information at which an extension line of another peripheral branch that is erroneously inserted with the catheter arrives at the surface of the lung region, the another peripheral branch being different from the specific peripheral branch and the arrival position information and the assumed mapping information representing a point or a range at which a dye arrives when the dye is sprayed from within the bronchial region toward the specific peripheral branch; and generating a mapping image obtained by mapping the arrival position information of the specific peripheral branch and the assumed mapping information to the surface of the lung region and displaying the mapping image on a display.
12. A non-transitory computer-readable storage medium storing therein a mapping image display control program that causes a computer to implement the method of claim 11.
13. A mapping image display control device, comprising: a processor configured to: extract a lung region included in a three-dimensional image; extract a bronchial region included in the lung region; acquire information on a branch position of the bronchial region; estimate arrival position information at which an extension line of a specific peripheral branch included in the bronchial region as a target branch arrives at a surface of the lung region on a basis of the information on the branch position; set a condition of a bronchus deformation of the bronchus in a case where a bronchoscope is inserted into the bronchus; estimate assumed mapping information at which an extension line of a deformed peripheral branch in which the specific peripheral branch is deformed according to the condition of the bronchus deformation arrives at the surface of the lung region, the arrival position information and the assumed mapping information representing a point or a range at which a dye arrives when the dye is sprayed from within the bronchial region toward the specific peripheral branch; and generate a mapping image obtained by mapping the arrival position information of the specific peripheral branch and the assumed mapping information to the surface of the lung region and display the mapping image on a display, wherein the bronchus deformation is determined based on deformation conditions of branch positions between a terminal of the specific peripheral branch and the proximal end portion of the bronchus, the deformation conditions being set for the respective branch position of the bronchial region in advance of the bronchoscope being inserted into a patient.
14. A mapping image display control method comprising: extracting a lung region included in a three-dimensional image; extracting a bronchial region included in the lung region; acquiring information on a branch position of the bronchial region; estimating arrival position information at which an extension line of a specific peripheral branch included in the bronchial region as a target branch arrives at a surface of the lung region on a basis of the information on the branch position; setting a condition of a bronchus deformation of the bronchus in a case where a bronchoscope is inserted into the bronchus; estimating assumed mapping information at which an extension line of a deformed peripheral branch in which the specific peripheral branch is deformed according to the condition of the bronchus deformation arrives at the surface of the lung region, the arrival position information and the assumed mapping information representing a point or a range at which a dye arrives when the dye is sprayed from within the bronchial region toward the specific peripheral branch; and generating a mapping image obtained by mapping the arrival position information of the specific peripheral branch and the assumed mapping information to the surface of the lung region and display the mapping image on a display, wherein the bronchus deformation is determined based on deformation conditions of branch positions between a terminal of the specific peripheral branch and the proximal end portion of the bronchus, the deformation conditions being set for the respective branch position of the bronchial region in advance of the bronchoscope being inserted into a patient.
15. A non-transitory computer-readable storage medium storing therein a mapping image display control program that causes a computer to implement the method of claim 14.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION
(14) Hereinafter, a medical image diagnosis support system using an embodiment of a mapping image display control device, method, and program of the present invention will be described in detail with reference to the drawings.
(15) A medical image diagnosis support system of this embodiment performs support in a case where the VAL-MAP method described above is performed and, basically, simulates a position of a lung surface on which a dye is exuded in a case where the dye is sprayed onto a peripheral part of a bronchus, and generates and displays a mapping image obtained by mapping the position to the lung surface. By observing this mapping image, a doctor can recognize a position of the lung surface at which the dye is exuded in a case where the bronchus is selected and the dye is sprayed onto the peripheral part thereof, and therefore, appropriately select the bronchus that is sprayed with the dye before surgery.
(16) Further, in the medical image diagnosis support system of this embodiment, in a case where a doctor selects a bronchus to which a dye is sprayed and actually inserts a bronchoscope into the selected bronchus as described above, a mapping image is generated and displayed on the assumption that a catheter is erroneously inserted into a different bronchus and a dye is sprayed as described above.
(17) The medical image diagnosis support system of this embodiment specifically includes a mapping image display control device 1, a medical image storage server 2, a display device 3 (corresponding to a display unit), and an input device 4, as illustrated in
(18) The mapping image display control device 1 is a mapping image display control device in which the mapping image display control program of this embodiment is installed on a computer.
(19) The mapping image display control device 1 includes a central processing unit (CPU), a semiconductor memory, and a storage device such as a hard disk or a solid state drive (SSD). The mapping image display control program of this embodiment is installed on the storage device. By the central processing unit executing the mapping image display control program, a medical image acquisition unit 10, a lung region extraction unit 11, a bronchial region extraction unit 12, a branch position information acquisition unit 13, an arrival position information estimation unit 14, and a display control unit 15 illustrated in
(20) The mapping image display control program is recorded on a recording medium such as a digital versatile disc (DVD), a compact disc read only memory (CD-ROM), distributed, and installed on the computer from the recording medium. Further, the mapping image display control program is stored in a state in which a storage device of a server computer connected to a network or a network storage can be accessed from the outside, and is downloaded and installed on the computer in response to a request.
(21) The medical image acquisition unit 10 acquires a three-dimensional image 6 of a chest of a patient that has been imaged in advance. The three-dimensional image 6, for example, is obtained by imaging the chest of the patient using a computed tomography (CT) device, a magnetic resonance imaging (MRI) device, or the like.
(22) The three-dimensional image 6 is stored in advance in the medical image storage server 2 together with patient identification information, and the medical image acquisition unit 10 reads out the three-dimensional image 6 having the identification information from the medical image storage server 2 on the basis of the patient identification information input by the user using the input device 4 or the like, and temporarily stores the three-dimensional image 6.
(23) The lung region extraction unit 11 performs a process of extracting a lung region from the three-dimensional image 6 of the chest acquired by the medical image acquisition unit 10. A known scheme such as a method of extracting the lung region by histogramming a signal value at each pixel position of the three-dimensional image 6 since a lung field is a region in which there is air, and performing threshold process on the lung region or a region spreading method based on a seed point indicating a lung region can be used as a method of extracting the lung region.
(24) The bronchial region extraction unit 12 performs a process of extracting a bronchial region included in the lung region of the three-dimensional image 6 of the chest. A bronchus included in the three-dimensional image 6 is indicated as a region indicating a small pixel value because a pixel inside the bronchus corresponds to an air region, but a bronchial wall is considered to be a cylinder or linear structure indicating a relatively large pixel value. Therefore, structure analysis of a shape based on a distribution of pixel values is performed for each pixel to extract the bronchus. For example, as in the method described in JP2012-200403A, it is possible to extract the bronchial region and a graph structure in which the bronchial region is thinned by performing Hessian analysis on the basis of the pixel value of each pixel. Other known schemes may be used as the method of extracting a bronchial region.
(25) The branch position information acquisition unit 13 acquires information on a branch position of the bronchial region extracted by the bronchial region extraction unit 12. Specifically, the branch position information acquisition unit 13 classifies a graph structure of the bronchial region extracted by the bronchial region extraction unit 12 into a start point, an end point, branch points, and edges, and acquires position information of the branch point as the information on the branch position of the bronchial region.
(26) The arrival position information estimation unit 14 estimates arrival position information at which an extension line of a peripheral branch included in the bronchial region arrives at a surface of the lung region on the basis of the information on the branch position acquired by the branch position information acquisition unit 13.
(27) Here, in the VAL-MAP method, in a case where a dye is sprayed onto a peripheral part of the bronchus, a position at which the dye arrives at a lung surface and is exuded after passing through the inside of a tissue of a lung can be estimated as a position at which an extension line of the peripheral branch of the bronchus arrives at the lung surface.
(28) Therefore, the arrival position information estimation unit 14 extracts the graph structure of the bronchial region from the three-dimensional image, and estimates a straight line set on the basis of information on a terminal of the peripheral branch included in the graph structure and the branch position acquired by the branch position information acquisition unit 13 as an extension line of the peripheral branch of the bronchial region. The arrival position information at which the extension line arrives at the surface of the lung region is estimated as a position at which the dye arrives at the lung surface.
(29) Specifically, as illustrated in
(30) In this embodiment, the first branch point from the terminal T is used, but the present invention is not limited thereto, and the extension line may be set using a second branch point, a third branch point, or the like from the terminal T.
(31) Further, although the terminal T of the peripheral branch of the graph structure of the bronchial region and the first branch point S from the terminal T are connected in this embodiment, the branch point S may not necessarily be used and a point near the branch point S may be used as long as substantially the same result can be obtained using the point. That is, the straight line set on the basis of the information on the branch position and the terminal of the peripheral branch in the graph structure is assumed to also include a straight line that is set by connecting the terminal T of the peripheral branch and the point near the branch point S.
(32) The arrival position information need not necessarily be coordinates of one point, and a two-dimensional or three-dimensional range including the intersection may be acquired as the arrival position information. The arrival position information is information indicating an arrival point or an arrival range in which the dye arrives at the lung surface after the dye passes through the inside of a tissue of the lung in a case where the dye is sprayed onto the peripheral part of the bronchus.
(33) Further, the arrival position information estimation unit 14 of this embodiment assumes erroneous insertion of the catheter described above in a case where a specific peripheral branch among peripheral branches of the bronchial region is a target branch to which the dye is sprayed, and estimates the arrival position information of the peripheral branch into which the catheter is erroneously inserted as assumed mapping information. Specifically, the arrival position information estimation unit 14 of this embodiment estimates arrival position information of a specific peripheral branch different from a specific peripheral branch extending from the branch position present between a proximal end portion of the bronchial region and the specific peripheral branch described above, as assumed mapping information. As a branch position present between the proximal end portion of the bronchial region and the specific peripheral branch, for example, in a case where a peripheral branch Br illustrated in
(34) Further, the display control unit 15 generates a volume rendering image of the lung region and the bronchial region on the basis of the lung region extracted by the lung region extraction unit 11 and the bronchial region extracted by the bronchial region extraction unit 12. Opacity of the volume rendering image of the lung region is set to such a degree that the bronchial region within the lung region can be visually recognized, and colors of the lung region and the bronchial region are set to different colors.
(35) Further, the display control unit 15 generates a mapping image obtained by superimposing the arrival position information estimated by the arrival position information estimation unit 14, the assumed mapping information, and the extension line set in a case where the arrival position information is estimated, to the volume rendering image of the lung region and the bronchial region, and displays the mapping image on the display device 3.
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(37) In a state in which the mapping image including the arrival position information as illustrated in
(38) In this case, the arrival position information estimation unit 14 estimates the above-described assumed mapping information in a case where the branch By related to the arrival position information P1 selected by the user is set as a specific peripheral branch and the branch Br is set as a target branch, and outputs the assumed mapping information to the display control unit 15.
(39) In a case where the assumed mapping information is input, the display control unit 15 generates and displays a mapping image obtained by superimposing only the arrival position information selected by the user and the arrival position information of the assumed mapping information on the volume rendering image.
(40) In the examples illustrated in
(41) Further, in the above description, the user selects the specific arrival position information in a case where the arrival position information of the assumed mapping information is displayed, but the present invention is not limited thereto. For example, the arrival position information may be automatically selected by specifying the arrival position information closest to the tumor region.
(42) Further, a size of the sphere indicating the arrival position information displayed within the mapping image can be arbitrarily set by the user using the input device 4. Further, the sphere indicating the arrival position information may be switchable between a display and a non-display, or may be displayed to blink. Further, the extension line of the bronchial region does not have to be necessarily displayed, and may be switchable between a display and a non-display by the user.
(43) The display device 3 includes a display device such as a liquid crystal display, and displays the above-described volume rendering image, and the like.
(44) The input device 4 receives various setting inputs from the user, and includes an input device such as a keyboard and a mouse. The input device 4 receives, for example, a setting input of identification information of a patient, a setting input of opacity and color of the volume rendering image, a setting input of the display shape and the size of the arrival position information, and a selection of the specific arrival position information. The display device 3 and the input device 4 may be integrated by using a touch panel.
(45) Next, an operation of the medical image diagnosis support system of this embodiment will be described with reference to a flowchart illustrated in
(46) First, the medical image acquisition unit 10 reads and acquires the three-dimensional image 6 from the medical image storage server 2 on the basis of the input of the identification information of the patient from the user (S10).
(47) The three-dimensional image 6 acquired by the medical image acquisition unit 10 is input to the lung region extraction unit 11 and the bronchial region extraction unit 12. The lung region extraction unit 11 extracts the lung region from the input three-dimensional image 6 (S12), and the bronchial region extraction unit 12 extracts the bronchial region from the input three-dimensional image 6 and acquires a graph structure in which the bronchial region is thinned (S14).
(48) The graph structure acquired by the bronchial region extraction unit 12 is input to the branch position information acquisition unit 13. The branch position information acquisition unit 13 acquires information on the branch position of the bronchial region on the basis of the input graph structure (S16).
(49) The information on the branch position acquired by the branch position information acquisition unit 13 is input to the arrival position information estimation unit 14. The arrival position information estimation unit 14 sets the extension line of the peripheral branch of the bronchial region on the basis of the input information on the branch position, and acquires information on an intersection between the extension line and the lung region surface as the arrival position information (S18).
(50) The lung region extracted by the lung region extraction unit 11 and the bronchial region extracted by the bronchial region extraction unit 12 are input to the display control unit 15. The display control unit 15 generates the volume rendering image on the basis of the input lung region and the input bronchial region. Further, the extension line of the peripheral branch of the bronchial region set in the arrival position information estimation unit 14, and the arrival position information are input to the display control unit 15. The display control unit 15 generates mapping image obtained by superimposing the input extension line of the peripheral branch and the input arrival position information on the volume rendering image of the lung region and the bronchial region (S20), and displays the mapping image on the display device 3 (S22).
(51) Then, in a case where the specific arrival position information is selected from among a plurality of pieces of arrival position information displayed on the mapping image (YES in S24), the arrival position information estimation unit 14 estimates the assumed mapping information in a case where the peripheral branch related to the arrival position information selected by the user is set as a specific peripheral branch and the branch is set as a target branch (S26), and outputs the assumed mapping information to the display control unit 15.
(52) In a case where the assumed mapping information is input, the display control unit 15 generates and displays a mapping image obtained by superimposing only the arrival position information selected by the user and the arrival position information of the assumed mapping information on the volume rendering image (S28).
(53) Next, a medical image diagnosis support system according to a second embodiment of the present invention will be described. A schematic configuration of the medical image diagnosis support system of the second embodiment is the same as that of the first embodiment illustrated in
(54) In a case where a specific peripheral branch is set as a target branch and a bronchoscope is actually inserted toward the target branch as described above, the bronchus may be bent due to stiffness of the bronchoscope. In this case, a direction in which the peripheral branch of the bronchus extends is likely to be different from a direction of the extension line set in a case where the arrival position information is estimated.
(55) Therefore, the arrival position information estimation unit 14 of the second embodiment assumes bending of the bronchus as described above in consideration of a load on the branch, estimates a direction in which the peripheral branch extends during surgery, and estimates the assumed mapping information on the basis of the estimated direction.
(56) Conditions of deformation (bending) of the bronchus in a case where the bronchoscope is inserted may be set, for example, for each peripheral branch in the bronchial region in advance, or deformation conditions may be set for each branch position of the bronchial region, a branch position present between the terminal of the specific peripheral branch and the proximal end portion of the bronchus may be specified in a case where a specific peripheral branch is selected, and the assumed mapping information may be estimated on the basis of the deformation condition of the specified branch position.
(57) Specifically, the arrival position information estimation unit 14 of the second embodiment estimates a branch Bra after deformation for a specific peripheral branch Br on the basis of its deformation condition, and estimates arrival position information Pra of the branch Bra, as illustrated in
(58) A region R on the lung region surface including both the arrival position information Pr of the specific peripheral branch Br and the arrival position information Pra of the branch Bra after deformation is estimated as the assumed mapping information. The region R may be a circle having a diameter that is a line segment connecting the arrival position information Pr to the arrival position information Pra, or may be a circle having a radius that is a line segment connecting the arrival position information Pr to the arrival position information Pra and having a center that is the arrival position information Pr. Further, the arrival position information Pra may be the assumed mapping information.
(59) In a case where the arrival position information Pr illustrated in
(60) The display control unit 15 generates and displays a mapping image obtained by superimposing the arrival position information Pr selected by the user, and an index indicating the region R and/or the arrival position information Pra on the volume rendering image.
(61) According to the medical image diagnosis support system of the first and second embodiments, since the condition considering the erroneous insertion of the catheter or the deformation of the bronchus is preset and the assumed mapping information is estimated on the basis of the condition and displayed on the mapping image, the user can determine a resection region of a tumor or the like in consideration of a positional deviation in a case where a dye is actually sprayed onto the peripheral part of the bronchus.
(62) Further, since a deviation of a staining position can be recognized in advance, it is not necessary to perform capturing of a CT image for confirming the staining position after staining treatment.
(63) In the first embodiment, the region may be set on the basis of the arrival position information of the specific peripheral branch and the assumed mapping information, and the mapping image obtained by superimposing the index indicating the region on the volume rendering image may be generated and displayed, similar to the second embodiment.
(64) Further, in a case where the assumed mapping information is estimated, arrival position information different from the arrival position information of the specific peripheral branch may be estimated in consideration of the erroneous insertion of the catheter as in the first embodiment and in consideration of the deformation of the bronchus as in the second embodiment, and accordingly, the assumed mapping information may be estimated.
(65) Further, in the first and second embodiments, the straight line connecting the terminal to the branch point in the graph structure is estimated as the extension line of the peripheral branch of the bronchial region, but a method of setting the extension line of the peripheral branch of the bronchial region is not limited thereto. For example, as illustrated in
(66) In a case where the curve L2 obtained by the spline interpolation is estimated as the extension line of the peripheral branch, it is possible to estimate the extension line of the peripheral branch with higher accuracy.
(67) Even in the case in which the extension line of the peripheral branch is estimated by the spline interpolation as described above, the branch point S may not be necessarily used or a point near the branch point S may be used so long as substantially the same result can be obtained.
(68) Further, although the spline interpolation is performed using the branch point S and the two points p1 and p2 on the peripheral branch in the above description, three or more points are set for points other than the branch point S. Further, the spline interpolation may be performed using at least one of point p1, the branch point S, or a point p3 on the peripheral branch on the trachea upstream side of the branch point S to estimate a curve L3, as illustrated in
(69) Further, the peripheral branch may be specified on the basis of the information on the branch position acquired by the branch position information acquisition unit 13, a dominant region of the specified peripheral branch in the lung region may be specified, and a straight line connecting a center of gravity of the dominant region to the terminal of the peripheral branch may be estimated as the extension line of the peripheral branch of the bronchial region.
(70) Specifically, as illustrated in
(71) Thus, in a case where the straight line L4 connecting the center of gravity G1 of the dominant region Ra to the terminal T of the peripheral branch B is estimated as the extension line of the peripheral branch B of the bronchial region, it is possible to estimate the extension line of the peripheral branch with higher accuracy on the basis of the anatomical point of view.
(72) Further, as another method of estimating the arrival position on the lung surface of the extension line of the peripheral branch using the dominant region of the peripheral branch of the bronchial region as described above, for example, the peripheral branch may be specified on the basis of the information on the branch position acquired by the branch position information acquisition unit 13, the dominant region of the specified peripheral branch in the lung region may be specified, and a center of gravity of a region that is a surface of the lung region in a surface of the dominant region may be estimated as the arrival position information.
(73) Specifically, as illustrated in
(74) Further, it is known that there are a pulmonary artery and a pulmonary vein around the bronchus, and an extension direction of the bronchus is similar to an extension direction of the pulmonary artery and the pulmonary vein. Therefore, a position at which the extension line of the peripheral branch of the bronchial region arrives at the lung surface may be estimated on the basis of information on the pulmonary artery or the extension direction of the pulmonary artery.
(75) Specifically, as illustrated in
(76) The arrival position information estimation unit 14 specifies the pulmonary artery region and the pulmonary vein region extending along the peripheral branch of the bronchial region on the basis of the information on the branch position acquired by the branch position information acquisition unit 13, and estimates the extension line of the peripheral branch of the bronchial region on the basis of the pulmonary artery region and the pulmonary vein region. Specifically, as illustrated in
(77) The branch point S is the first branch point b1 from the terminal T of the peripheral branch of the graph structure to the trachea upstream side. Further, the position v1 in the pulmonary artery region closest to the branch point S (b1) is a position in the pulmonary artery region of which the distance to the branch point S is the shortest, and the position a1 in the pulmonary vein region closest to the branch point S is a position in the pulmonary vein region of which the distance to the branch point S is the shortest. Further, the position v2 in the pulmonary artery region closest to the terminal T (b2) is a position in the pulmonary artery region of which the distance to the terminal T is the shortest, and the position a2 in the pulmonary vein region closest to the terminal T is a position in the pulmonary vein region of which the distance to the terminal T is the shortest.
(78) A direction from the position v1 to the position v2 in the pulmonary artery region is estimated as the extension direction of the pulmonary artery region to set a first vector, a direction from the position a1 to the position a2 in the pulmonary vein region is estimated as the extension direction of the pulmonary vein region to set the second vector, and an average of the first vector and the second vector is calculated. A straight line L5 obtained by extending such an average vector is estimated as the extension line of the peripheral branch of the bronchial region, and a position at which this extension line arrives at the lung surface is acquired.
(79) By estimating the extension line of the peripheral branch using the pulmonary vein region and the pulmonary artery region as described above, it is possible to estimate the extension line of the peripheral branch with higher accuracy on the basis of the anatomical point of view.
(80) Although the first vector is set using the position v1 and the position v2 in the pulmonary artery region and the second vector is set using the position a1 and the position a2 in the pulmonary vein region in the above description, for example, spline interpolation may be performed to set a first curve using the position v1 and the position v2 in the pulmonary artery region and a point between these positions, the spline interpolation may be performed to set a second curve using the position a1 and the position a2 in the pulmonary vein region and a point between these positions, and a curve obtained by averaging the first curve and the second curve may be estimated as the extension line of the peripheral branch of the bronchial region.
(81) Further, although the extension line of the peripheral branch is estimated using both of the pulmonary vein region and the pulmonary artery region in the above description, the extension line of the peripheral branch may be estimated using only one of the pulmonary vein region and the pulmonary artery region. For example, a straight line that is parallel to the first vector set on the basis of the pulmonary artery region and passes through the terminal T of the peripheral branch may be estimated as the extension line of the peripheral branch. Further, a straight line that is parallel to the second vector set on the basis of the pulmonary vein region and passes through the terminal T of the peripheral branch may be estimated as the extension line of the peripheral branch.