JP5420474B2 - Medical image diagnosis support apparatus and method, and program - Google Patents

Description

  The present invention relates to a technique for supporting comparative observation of a plurality of images obtained from each of a plurality of three-dimensional medical images.

  In recent years, in various clinical scenes, a diagnosis is made by comparing and observing a plurality of medical images obtained by photographing the same patient. Specifically, observation of time-lapse images at different shooting timings for follow-up of the lesion, observation of images before and after contrast for observation of blood flow dynamics of the affected area, and morphology and function of the affected area In order to observe both of them, images taken with different modalities are observed, and in order to grasp the affected area in detail, the taken posture is changed and images taken are observed. Thus, by comparing and observing a plurality of images, knowledge that cannot be obtained by observing a single image can be obtained.

  For example, in a CT examination of the large intestine, it is possible to observe a polyp and identify a polyp and a residue by comparatively observing CT images taken in a supine position and a prone position. In Patent Document 1, a series of viewpoint positions along the structure of the colon is determined for each of the colon images obtained in the supine position and the prone position, and a two-dimensional representation of the colon at the corresponding viewpoint position is made. And a method of generating a three-dimensional display image and displaying it simultaneously.

JP-T-2001-511031

  In the method described in Patent Document 1, as the viewpoint position in the image in one shooting posture is changed, the viewpoint position in the image in the other shooting posture is changed, and the image at each viewpoint position after the change is displayed. When doing so, it is necessary to redisplay both display images. Furthermore, if the image is generated at the changed viewpoint position every time the viewpoint position is changed, the display image needs to be regenerated before redisplaying. Therefore, even if the amount of displacement of one viewpoint position is slight, the viewpoint position of the other image will be changed accordingly, not only regenerating / redisplaying one display image, It is also necessary to regenerate / redisplay the other display image, resulting in a significant calculation cost.

  The present invention has been made in view of the above circumstances, and corresponds to each observation path set for each of a plurality of three-dimensional medical images while changing a given reference point. An object of the present invention is to provide an apparatus, a method, and a program for realizing a reduction in calculation cost associated with a change in a reference point when displaying an observation image based on each reference point in a comparable manner. .

  The medical image diagnosis support apparatus of the present invention sets the first observation path for the first three-dimensional medical image and performs the second three-dimensional comparison target with the first three-dimensional medical image. An observation path setting means for setting a second observation path corresponding to the first observation path for the three-dimensional medical image; a first reference point in the first observation path; Reference point setting means for setting a second reference point corresponding to the first reference point in two observation paths, and obtained from the three-dimensional medical image, passing through the reference point, or from the reference point A means for displaying a viewed observation image on a display means, the first observation image based on the first reference point obtained from the first three-dimensional medical image, and the second three-dimensional medical image; Can be compared with the second observation image based on the second reference point obtained from Display control means for displaying in various forms, first reference point changing means for changing the position of the first reference point in the first observation path, and the first reference point before and after the change If the displacement is so small that it does not satisfy the predetermined second reference point changing condition, the position of the second reference point is not changed, and the displacement satisfies the second reference point changing condition. If larger, second reference point changing means for changing the second reference point to a position corresponding to the first reference point after the change is provided, and the display control means is provided before the change. The display of the first observation image based on the first reference point is updated to the first observation image based on the first reference point after the change, and the position of the second reference point is When the second observation image is changed, the second observation image based on the second reference point before the change is changed. It indicates characterized in that so as to update the second observation image based on the second reference points after the change.

  The medical image diagnosis support method of the present invention sets the first observation path for the first three-dimensional medical image and performs the second three-dimensional comparison target with the first three-dimensional medical image. A step of setting a second observation path corresponding to the first observation path for the three-dimensional medical image; setting a first reference point in the first observation path; and the second observation path Setting a second reference point corresponding to the first reference point in the path, and displaying an observation image obtained from the three-dimensional medical image, passing through the reference point, or viewed from the reference point Displaying on the means, the first observation image based on the first reference point obtained from the first three-dimensional medical image and the second obtained from the second three-dimensional medical image The second observation image based on the reference point is displayed in a comparable manner. A step of changing the position of the first reference point in the first observation path, and a displacement of the first reference point before and after the change is a predetermined second reference point change condition If the second reference point is not so large that the position of the second reference point is not changed, and if the displacement is large enough to satisfy the second reference point change condition, the second reference point is not changed. , Changing to a position corresponding to the first reference point after the change, and displaying the first observation image based on the first reference point before the change to the first reference after the change Update to the first observation image based on a point, and if the position of the second reference point is changed, the second observation image based on the second reference point before the change is updated. A step of updating the display to the second observation image based on the second reference point after the change. And having a flop.

  The medical image diagnosis support program of the present invention is for causing a computer to function as each of the above means.

  Here, the “first three-dimensional medical image” and the “second three-dimensional medical image” represent a subject to be subjected to comparative observation. Specifically, images with different imaging time points, images with different imaging conditions, images with different body postures and postures at the time of imaging, images representing each of the structures in the subject existing in pairs, etc. It is done.

  Further, in the case where each three-dimensional medical image represents the luminal structure or branch structure of the subject, the “observation path” may be a path along the luminal structure or branch structure. The body axis of the subject may be used as the observation path.

  The “observation path” may be set as a point sequence or a line, or may be set as a path having a certain width / thickness. For example, when the observation target is a luminal structure, the former specific example is that the core line connecting the centers of the luminal structure is used as the observation path, and the latter specific example is that the luminal structure itself or the luminal structure is a cylinder. For example, a structure approximated by, for example, the observation path may be used.

  The specific method of “setting the observation path” may be a method of automatically setting the observation path using an image recognition method or the like according to the observation path, or a manual operation of the user using the input means May be used to set the observation path, or the automatically set observation path may be corrected manually or automatically by interpolation calculation based on the manually set partial observation path. The entire observation path may be set.

  The “observation image” is an image passing through the reference point or an image viewed from the reference point. A specific example of the former includes a cross-sectional image representing an arbitrary cross-section passing through a reference point, and a specific example of the latter includes a projection image generated by central projection or parallel projection with the reference point as a viewpoint.

  The observation image may be sequentially generated every time the reference point is set or changed, or the correspondence between the first reference point and the second reference point is set in advance and set. An observation image at each reference point may be generated in advance. In addition, when the three-dimensional medical image is configured by stacking a plurality of tomographic images, the reference point corresponds to the cross-sectional position of the tomographic image, and the observation image is the tomographic image, an observation image is generated. No processing is required.

  “Displaying the first observation image and the second observation image in a comparable manner” means, for example, displaying the first observation image and the second observation image side by side simultaneously, It is possible to switch to the same position for display.

  The specific method of “changing the position of the first reference point” may be a method of automatically changing the position of the first reference point as if the navigation is automatically performed in the first observation path. Alternatively, it may be a method of accepting a user's manual operation using the input means and changing the position of the first reference point.

  In the present invention, each of the first and second observation paths is divided into a plurality of corresponding blocks, and the first reference point is set at any position in an arbitrary block in the first observation path. Even in such a case, a predetermined second reference point in the block in the second observation path corresponding to the block to which the first reference point belongs is set, and the second reference point change condition is If the block to which the first reference point belongs is different before and after the change of the first reference point, and the displacement of the first reference point satisfies the second reference point change condition, the second reference point May be changed to a predetermined position in the block in the second observation path corresponding to the block to which the changed first reference point belongs.

  In this case, the observation path may be divided into a plurality of blocks based on the anatomical classification of the observation target represented in the three-dimensional medical image. For example, when the observation target is a branch structure and an observation path along the branch structure is set, the observation path may be divided into a plurality of blocks in the branch structure branching unit. Alternatively, the observation path may be divided into a plurality of blocks by dividing the entire length of the observation path at equal intervals or by dividing the observation path at a given length from the start point or end point of the observation path. .

  Further, the position of the second reference point in the block in the second observation path may be, for example, the midpoint of the block (observation path) or the center of gravity of the block (area).

  On the other hand, in the present invention, the second reference point changing condition may be a condition that the amount of displacement of the first reference point before and after the change of the first reference point is larger than a predetermined threshold value. That is, the position where the second reference point corresponds to the first reference point after the change only when the amount of displacement of the first reference point before and after the change of the first reference point is larger than a predetermined threshold. You may make it change to.

  The present invention may be applied to three or more three-dimensional medical images. In this case, for example, one of three or more three-dimensional medical images may be a first three-dimensional medical image, and each of the other three-dimensional medical images may be handled in the same manner as the second three-dimensional medical image. It is done.

  In the present invention, the first and second corresponding to the corresponding observation paths set for each of the first and second three-dimensional medical images which are the two three-dimensional medical images to be compared and observed. A reference point is set, and each observation image obtained based on each three-dimensional medical image and each reference point is displayed in a comparable manner. Here, when the position of the first reference point is changed, if the displacement of the first reference point before and after the change is small enough not to satisfy the predetermined second reference point change condition, If the displacement of the first reference point is large enough to satisfy the second reference point change condition, the second reference point is changed to the first reference point after the change. The display of the first observation image is updated to the one after the change and the second observation image is displayed only when the position of the second reference point is changed. Update to the new one. This makes it possible to display the first and second observation images based on the corresponding reference points by associating the first reference point and the second reference point in a many-to-one relationship. The second reference point is not changed every time the reference point is changed. As a result, the calculation cost for updating the display of the second observation image is reduced, and the processing speed is increased.

1 is a schematic configuration diagram of a medical image diagnostic system in which a comparative observation function according to an embodiment of the present invention is implemented. The block diagram which showed typically the structure and process flow which implement | achieve the comparative observation function in the 1st Embodiment of this invention The flowchart showing the flow of the comparative observation of the medical image using the medical image diagnostic system in the first embodiment of the present invention. A diagram schematically showing the observation path of the large intestine set for a 3D medical image obtained in the supine position A diagram schematically showing the observation path of the large intestine set for a three-dimensional medical image obtained in the prone position A diagram that schematically shows an example of the observation path block and reference points of the large intestine in the supine and prone positions A diagram showing an example of an observation image (virtual endoscopic image) in the supine position A figure showing an example of an observation image (virtual endoscopic image) in the prone position The figure which represented typically the 1st modification of the observation path block and reference | standard point of the large intestine in the supine position and the prone position The figure which represented typically the 2nd modification of the observation path block and reference | standard point of the large intestine in the supine position and the prone position The block diagram which showed typically the structure which implement | achieves the comparative observation function in the 2nd Embodiment of this invention, and the flow of a process The flowchart showing the flow of the comparative observation of the medical image using the medical image diagnostic system in the second embodiment of the present invention. The figure which represented typically an example of the setting / change of the reference point in the 2nd Embodiment of this invention A diagram schematically showing an example of dividing into observation path blocks according to the branch structure of pulmonary blood vessels (one lung) A diagram schematically showing an example of dividing into observation path blocks according to the branch structure of pulmonary blood vessels (the other lung)

  Hereinafter, an embodiment of the present invention will be described by taking as an example the case of performing comparative observation of medical images representing the large intestine of a human body in the supine position and the prone position.

  FIG. 1 is a hardware configuration diagram showing an outline of a medical image diagnostic system in which a comparative observation function for medical images according to an embodiment of the present invention is implemented. As shown in the figure, in this system, a modality 1, an image storage server 2, and an image processing workstation 3 are connected via a network 9 in a communicable state.

  The modality 1 generates image data of a three-dimensional medical image representing the region by imaging the region to be examined of the subject, and the image data is defined by the DICOM (Digital Imaging and Communications in Medicine) standard. A device for adding incidental information and outputting it as image information is included. Specific examples include CT and MRI. In the present embodiment, the CT scan is used to scan the human body in the supine position in the body axis direction in the supine position, and then in the prone position to represent the abdomen including the large intestine of the human body. Three-dimensional image data at each position is generated.

  The image storage server 2 is a computer that stores and manages medical image data acquired by the modality 1 and image data of medical images generated by image processing at the image processing workstation 3 in an image database. A device and database management software (for example, ORDB (Object Relational Database) management software) are provided.

  The image processing workstation 3 performs image processing (including image analysis) on the medical image data acquired from the modality 1 or the image storage server 2 in response to a request from the interpreter, and displays the generated image. A computer having a well-known hardware configuration such as a CPU, main storage device, auxiliary storage device, input / output interface, communication interface, input device (mouse, keyboard, etc.), display device (display monitor), data bus, etc. The operating system is installed. The medical image comparison / observation function of the present invention is implemented in the image processing workstation 3, and this processing is realized by executing a program installed from a recording medium such as a CD-ROM. The program may be installed after being downloaded from a storage device of a server connected via a network such as the Internet.

  The storage format of image data and communication between devices via the network 9 are based on a protocol such as DICOM.

FIG. 2 is a block diagram showing a part of the functions of the image processing workstation 3 related to the medical image comparison observation function according to the first embodiment of the present invention. As shown in the figure, the comparative observation function for medical images according to the first embodiment of the present invention includes an observation path setting unit 31, an observation path dividing unit 32, a reference point setting unit 33, an observation image generating unit 34, and display control. This is realized by the unit 35, the first reference point changing unit 36, and the second reference point changing unit 37. From the three-dimensional medical images V1 and V2, the observation paths PT1 and PT2, and the divided observation path blocks PT1 [1] to PT1 [N _B ] and PT2 [1] in the supine position and the prone position, respectively. PT2 [N _B ], reference points RP1 _k , RP2 _m (k and m are natural numbers, 1 and 2 in the figure), observation images I1 _k and I2 _m , and observation of both supine and prone positions The display screens SC and SC ′ including the images are data read / written from / to a predetermined memory area of the image processing workstation 3 by the respective processing units.

  FIG. 3 is a flowchart showing control of a user operation, calculation processing, display processing, and the like under execution of software for comparative observation of medical images according to the first embodiment of the present invention. The flow of comparative observation that is the first embodiment of the present invention will be described with reference to FIG.

  First, three-dimensional medical images V1 and V2 (hereinafter referred to as a supine position original image and a prone position original image, respectively) in the supine position and the prone position are formed by imaging the abdomen of the subject with the modality 1. The image processing workstation 3 acquires the supine original image V1 and the prone original image V2 formed by the modality 1 (# 1).

Here, the observation path setting unit 31 sets an observation path along the large intestine in each original image. That is, the observation path setting unit 31 sets the observation path PT1 (hereinafter referred to as the supine position observation path) for the supine position original image V1, and the supine position observation path for the prone position original image V2. A corresponding observation path PT2 (hereinafter referred to as prone position observation path) is set (# 2). The observation path division unit 32, each of the observation path PT1, PT2, divided into mutually corresponding N _B blocks (# 3). Thus, the supine position observation path PT1 is divided into the supine position observation path block PT1 [1] to PT1 [N _B ], and the prone position observation path PT2 is divided into the prone position observation path blocks PT2 [1] to PT2 [N _B ] Is divided.

Next, the reference point setting unit 33 sets a reference point RP1 ₁ (hereinafter referred to as a supine position reference point) in the supine position observation path PT1, and at the supine position reference point RP1 ₁ in the prone position observation path PT2. A reference point RP2 ₁ (hereinafter referred to as a prone position reference point) corresponding to is set (# 4). Here, the reference point setting unit 33, even when setting the supine position reference point RP1 ₁ supine observation path block (e.g. N-th PT1 [N]) in the throat position, the supine observed path block PT1 [N] the corresponding prone position observation path block, i.e. a prone position reference point RP2 ₁ in position (where the center of gravity) of the N-th prone observation path block PT2 in [N] Set.

Observation image generating unit 34, supine reference point RP1 ₁ from the observation image I1 ₁ viewed (hereinafter, referred to as supine observation image) and generates from the supine KuraiHara image V1, viewed from prone position reference point RP2 ₁ The observed image I2 ₁ (hereinafter referred to as the prone position observed image) is generated from the prone position original image V2 (# 5). The display control unit 35 generates a display screen SC in which the generated supine position observation image I1 _{1 and} prone position observation image I2 ₁ are arranged so as to be comparatively observable, and displays them on the display of the image processing workstation 3 (# 6).

Here, the first reference point changing unit 36 receives an operation to move the supine position reference point, changing the supine position reference point RP1 ₁ different points RP1 ₂ (# 7), the observation image generating unit 34 changes supine reference point RP1 to generate a supine observation image I1 ₂ viewed from ₂ (# 8), the display control unit 35 later, updates the display of the supine position observation image on the display screen SC from I1 ₁ to I1 ₂ (# 9).

Further, the second reference point changing unit 37 determines whether the change of the supine position reference path exceeds the supine position observation path block, that is, whether the supine position observation path block to which the supine position reference point belongs before and after the change is different. Judgment is made (# 10). As a result of the determination, if the supine position observation path block to which the supine position reference point before and after the change is different (# 10; YES), the prone position reference point RP2 ₁ is changed to the supine position reference point RP1 ₂ after the change. a position corresponding to (RP2 _2), i.e., prone observation path block PT2 corresponding to a supine position observation path block the supine position reference point RP1 ₂ after the change belongs (e.g. PT1 [N + 1]) [ N + 1 ] Is changed to a predetermined position (RP2 ₂ ) (# 11). Then, the observation image generation unit 34 generates the prone position observation image I2 ₂ viewed from the changed prone position reference point RP2 ₂ (# 12), and the display control unit 35 displays the prone position in the display screen SC. The display of the position observation image is updated from I2 ₁ to I2 ₂ (# 13). On the other hand, supine observation path if the block is the same Field of the supine position reference point RP1 ₂ before and after change (# 10; NO), changes prone reference point RP2 ₂ is not performed.

Until the operation for ending the comparative observation is performed (# 14; YES), the operations and processes from the above steps # 7 to # 13, that is, the supine position reference point sequentially changed and changed along the supine position observation path Generation of supine position observation image viewed from the later supine position reference point, update of display, appropriate change of the corresponding prone position reference point, and change of the prone position observation image viewed from the changed prone position reference point Generation and display update are repeated (# 14; NO). In this description, every time the reference point is changed, subscripts of subscripts such as RP1 ₁ , RP1 ₂ , RP1 ₃ ,..., RP2 ₁ , RP2 ₂ , RP2 ₃ ,. Is expressed by adding one by one. The same applies to observation images in the supine position and prone position. In addition, the prone position reference point is not necessarily updated every time the supine position reference point is changed by the determination process in Step # 10, so the corresponding supine position reference point and the prone position reference point are attached. The character values do not always match.

  Next, details of processing performed by each processing unit in the image processing workstation 3 will be described.

  The observation path setting unit 31 extracts a large intestine region from each of the original images V1 and V2, and performs a core line extraction process on the extracted large intestine region. Then, the large intestine region and the core line extracted from the original images V1 and V2 are displayed on the image processing workstation 3, and the end point of the large intestine core line by the user's operation of the mouse or the like becomes the start point of the observation path. The specification of the end point of is accepted. As a result, observation paths PT1 and PT2 are set along the core of the large intestine from the designated end point to the other end point. FIG. 4A schematically shows the observation path PT1 of the large intestine from the start point SP1 to the end point EP1 set for the supine position original image V1, and FIG. 4B shows the prone position original image V2. 4 schematically shows the observation path PT2 of the large intestine from the start point SP2 to the end point EP2 set for. As shown in the figure, the imaging direction is reversed between the supine position and the prone position, so the shape of the large intestine and the observation path in each imaging position are generally mirror images of each other. The shape and position of the large intestine at each imaging position varies due to the influence of gravity due to differences and differences in imaging timing, etc., so the shape of the large intestine and observation path, the total length of the observation path, and the corresponding local range The length of the observation path is slightly different.

  In addition, in the large intestine extraction processing, first, for each axially disconnected image obtained from a three-dimensional medical image by a cross section perpendicular to the body axis (axial), based on the body surface by a known method. A process to separate the body from the body region is performed. As a specific example, there is a method of performing binarization processing on the input axial sectional image, extracting a contour by contour extraction processing, and extracting the inside of the extracted contour as a body (human body) region, etc. . Next, binarization processing is performed on the in-vivo region with a threshold value, and a large intestine region candidate in each axial dislocation image is extracted. Specifically, since air is contained in the large intestine duct, binarization is performed by setting a threshold value corresponding to the CT value of the air, and the air region in the body of each axial dislocation image is extracted. Finally, only a portion where the extracted internal air regions are connected between the axial dislocation images is extracted as a large intestine region.

  In the core line extraction process, a core line passing through the central portion of the colon tube is extracted from the extracted large intestine region by a known method. As a specific example, a method of performing a three-dimensional thinning process on a binarized image representing a large intestine region obtained by extracting only a portion to which a body air region is connected, which is obtained at the time of extraction of the large intestine (Japanese Patent Laid-Open No. 2004-2006 No. 283373) and the like.

  Here, a user interface for manually correcting the extraction result of the large intestine or the core may be further provided. As a specific example, the extracted large intestine region or core line is highlighted for each axial discontinuity image, and the user displays the large intestine region or core line whose extraction result is incorrect for each axial discontinuity image (represents the core line on the image) An interface in which the user corrects the point by operating the mouse or the like.

Observation path division unit 32 obtains the total length of the input observation path (core of the large intestine), the total length is divided by the number of blocks N _B, to calculate the length along the core line of the observation path blocks . Next, by setting the position of the cross section for each calculated length from the starting point of the observation path on the core line, and dividing the large intestine region by a cross section perpendicular to the tangential direction of the observation path at that position, Obtain the observation path block. As a result, the supine position observation path PT1 is divided into the supine position observation path block PT1 [1] to PT1 [N _B ], and the prone position observation path PT2 is divided into the prone position observation path blocks PT2 [1] to PT2 [N _B ] Is divided. FIG. 5 schematically shows the observation path blocks in the Nth, N + 1th, and N + 2th photographing positions. Thus, each observation path block represents a small area in the large intestine defined by a cross section perpendicular to the tangential direction of the observation path and the outline of the large intestine area. In addition, observation path blocks corresponding to numbers in [] in the supine position and prone position observation path blocks correspond to each other. The information of each observation path block includes position information associated with information for identifying each block and capable of specifying the area range of each block, and includes the subsequent reference point setting unit 33 and the second reference point. This is used for processing for obtaining the position of the center of gravity of the prone position observation path block in the point changing unit 37 and for specifying the block to which the supine position reference point belongs in the second reference point changing unit 37. Further, the number of blocks N _B can start parameter in the configuration file or program, the user input or the like, a pre-given value.

Reference point setting unit 33 first sets the supine position reference point RP1 ₁ supine observation path within PT1. Specifically, the supine position observation path PT1 (colon region and core line) schematically shown in FIG. 4A is displayed on the display, and the user designates a desired point on the supine position observation path PT1 using a mouse or the like. by, accepts the setting of the supine position reference point RP1 _1. Alternatively, it may be automatically set the start point SP1 of the supine observation path PT1 as an initial supine reference points RP1 _1. Then, the reference point setting unit 33 sets the prone position reference point RP2 ₁ corresponding to the supine position reference point RP1 _1. Specifically, as shown in FIG. 5, if the supine reference point RP1 ₁ (RP1 _{K in the} figure) belongs to the Nth observation path block PT1 [N], the corresponding prone position reference point RP2 ₁ (RP2 _{M in the} figure) is set to the position of the center of gravity of the Nth prone position observation path block PT2 [N] corresponding to the supine position observation path block PT1 [N].

The observation image generation unit 34 uses, as a viewpoint, an input reference point as a viewpoint, and outputs a projection image by central projection obtained by projecting image information on a plurality of lines of sight extending radially from the viewpoint onto a given projection plane from the three-dimensional medical image. Generate. The generated projection image is a virtual endoscopic image representing a state as if the inside of the large intestine was observed with an endoscope. Thus, as illustrated in FIG. 6A, with supine virtual endoscopic image I1 ₁ as viewed from the reference point RP1 ₁ is produced from a supine KuraiHara image V1, as illustrated in Figure 6B, prone position virtual endoscopic image I2 ₁ as viewed from the reference point RP2 ₁ is produced from a prone KuraiHara image V2. As a specific method of central projection, for example, a known volume rendering method can be used. The angle of view (the range of the line of sight) and the center of the visual field (center of the projection direction) of the virtual endoscope can be given in advance by a setting file, a program start parameter, user input, and the like.

  The display control unit 35 generates a display screen in which the supine position observation image and the prone position observation image are arranged so as to be comparatively observed, and displays them on the display of the image processing workstation 3. Here, both observation images may be switched and displayed in the same region in the display screen. In addition, when the observation image is regenerated based on the changed reference point due to the change of the reference point, the display control unit 35 updates only the display of the regenerated observation image on the display screen. .

The first reference point changing unit 36 first receives an instruction for moving the supine position reference point along the supine position observation path PT1 by the user's operation of the mouse or the like. Specifically, the mouse wheel operation may be detected, and the supine position reference point may be moved along the supine position observation path PT1 in accordance with the amount of the wheel. Similarly to the reference point setting unit 33, The supine position observation path PT1 schematically shown in FIG. 4A is displayed on the display, and the user designates a desired point on the supine position observation path PT1 using a mouse or the like. You may make it accept a setting. Next, the first reference point changing unit 36 changes the supine position reference point RP1 ₁ to a different point RP1 ₂ and writes it in a predetermined area of the memory. Note that the first reference point changing unit 36 may automatically move the supine position reference point by a predetermined distance along the supine position observation path PT1 at predetermined time intervals.

  The second reference point changing unit 37 first identifies which supine position observation path block each position belongs to based on the position of the supine position reference point before and after the change. Next, it is determined whether the supine position observation path block to which the supine position reference point belongs before and after the change is different. If the supine position observation path block to which the supine position reference point before and after the change is different as a result of the determination, the prone position reference point is changed to the supine position observation path block to which the supine position reference point after the change belongs. Change to the position of the center of gravity of the corresponding prone position observation path block. On the other hand, when the supine position observation path block to which the supine position reference point belongs before and after the change is the same, the prone position reference point is not changed.

FIG. 5 schematically shows how each reference point is changed in the observation path of the large intestine in the supine position and the prone position. As shown in the figure, when the supine position reference point is at the position of RP1 _K in the Nth supine position observation path block PT1 [N], the prone position reference point is the supine position observation path block PT1 [ N] will be in the center-of-gravity position RP2 _M of the N-th prone observation path block PT2 [N] corresponding to. At this time, the supine position observation image I1 _K and the prone position observation image I2 _M are displayed on the display. Here, when the first reference point changing unit 36 receives an operation of changing the supine position reference point from RP1 _K to RP1 _{K + 1} , the changed supine position reference point RP1 _{K + 1} is the same as before the change. Furthermore, since it belongs to the Nth supine position observation path block PT1 [N], the prone position reference point remains RP2 _M and is not changed. As a result, the supine position observation image is updated from I1 _K to I1 _{K + 1} , but the prone position observation image is not updated as I2 _M. Furthermore, when the position of the supine position reference point is sequentially changed, the display of the supine position observation image is referred to as I1 _{K + 2} , I1 _{K + 3} ... According to the position of the supine position reference point after the change. As long as the changed supine position reference point belongs to the Nth supine position observation path block PT1 [N] (the supine position reference points RP1 _K to RP1 _{K + P in} FIG. 5). The corresponding prone position reference point remains unchanged at RP2 _M , and the prone position observation image remains unchanged at I2 _M.

When the position of the supine position reference point is changed to RP1 _{K + P} , the supine position reference point RP1 _{K + P} is the next block, the (N + 1) -th supine position observation path block PT1 [N + 1 ], The block to which the supine reference point belongs is changed before and after the change. Accordingly, the second reference point changing unit 37, the position of the prone reference point, from RP2 _M, supine observation path block PT1 first N + 1 th prone observation path block corresponding to the [N + 1] Change to the center of gravity position RP2 _{M + 1} of PT2 [N + 1]. Accordingly, the observation image I1 _{K + P} based on the supine position reference point RP _{K + P} is generated and the display is updated, and the prone position observation image I2 based on the prone position reference point RPM _{+ 1 M + 1} is generated, the display of the prone position observation image of the display is also updated I2 _{M + 1} from I2 _M. The same applies to the case where the supine position observation path block to which the supine position reference point belongs changes from PT1 [N + 1] to PT1 [N + 2] with the change of the position of the supine position reference point.

  As described above, in the first embodiment of the present invention, when the second reference point changing unit 37 does not change the block to which the supine position reference point belongs before and after the change of the supine position reference point, the prone position reference Do not change the position of the point, and change the prone position reference point to the position corresponding to the changed supine position reference point only when the block to which the supine position reference point belongs is different before and after the change. Accordingly, the observation image generation unit 34 regenerates the supine position observation image based on the changed supine position reference point, and the position of the prone position reference point is changed for the prone position observation image. Only, the display control unit 35 updates the display of only the regenerated observation image. As a result, the supine position reference point and the prone position reference point are associated in a many-to-one relationship, and it is possible to display the supine and prone observation images based on the corresponding reference points. The prone position reference point is not changed every time the change is made. As a result, the calculation cost for regenerating the prone position observation image and updating the display is reduced, and the processing speed is increased.

  In addition, as in the present embodiment, in the image diagnosis of the large intestine, it is useful to compare and observe the images obtained in the supine position and the prone position. The shape and position of the large intestine at each photographic position fluctuate due to differences in the imaging position, so the shape of the large intestine and the observation path, the total length of the observation path, and the length of the observation path in the corresponding local range are There may be slight differences between images. Therefore, if the supine position reference point and the prone position reference point are associated with each other on a one-to-one basis, an error may be included in the correspondence relationship between the reference points due to the difference between the two images. The change of the reference point can be confusing for the observer. In this respect, in the present embodiment, the supine position reference point and the prone position reference point are associated in many-to-one correspondence, so that an error in the correspondence between the reference points can be absorbed, and confusion of the observer can be prevented. Become.

  In the above embodiment, an operation for moving the prone position reference point and an operation for adjusting the field of view of the prone position observation image are accepted, and the prone position observation image is regenerated and displayed according to these operations. By doing so, it is possible to supplement the fact that the observation range by the prone position observation image is limited by the above-mentioned many-to-one correspondence.

  In the above embodiment, the observation path dividing unit 32 may divide the observation path into a plurality of blocks using other methods. For example, the observation path dividing unit 32 may divide the observation path block into observation path blocks every given length from the start point of the observation path on the core line of the observation path. Here, the (given) length of the core line corresponding to each observation path block at the time of division can be a value given in advance by a setting file, a program start parameter, user input, and the like. In addition, as schematically illustrated in FIG. 7, the observation path dividing unit 32 may divide only the core line into a plurality of observation path blocks instead of dividing the large intestine region into blocks. In this case, the reference point setting unit 33 and the second reference point changing unit 37 may use, for example, the midpoint of the core line in each divided block as the prone position reference point.

  Further, in the above embodiment, as schematically illustrated in FIG. 8, the supine position reference point can be set or moved to an arbitrary position in the large intestine region, and the reference point setting unit 33 or the second reference point can be moved. The changing unit 37 may associate the position of the center of gravity of the corresponding prone position observation path block with the supine position reference point at any position in the supine position observation path block as the prone position reference point. .

  In the second embodiment of the present invention, the same effect as described above can be obtained without dividing the observation path into a plurality of blocks. That is, the second embodiment of the present invention is realized by a configuration in which the observation path dividing unit 32 is removed from the first embodiment as shown in the block diagram of FIG. 9, and as shown in the flowchart of FIG. In addition, step # 3 in the first embodiment is removed, and the determination process in step # 10 is replaced with step # 29.

More specifically, in step # 23 in FIG. 10, the reference point setting unit 33, the first embodiment corresponding to the supine position reference point RP1 ₁ which is set in the same manner as the embodiment, a prone position on observation path PT2 setting the prone position reference point RP2 ₁ to position. Here, prone reference point RP2 _2, for example, with respect to the total length of the prone position observation path PT2, the ratio from the start point SP2 to the prone position reference point RP2 ₂ length of the prone position observation path PT2 is, with respect to the total length of the supine observation path PT1, to match the supine position to the reference point RP1 ₁ ratio of length from the start point SP1 of the supine observation path PT1, it may be determined that position.

  In addition, the second reference point changing unit 37 is given a cumulative displacement amount of the supine position reference point from the position of the corresponding supine position reference point when the prone position reference point was previously set or changed. It is determined whether or not the threshold value is exceeded (step # 29 in FIG. 10). If the threshold value is exceeded (# 29; YES), the prone position reference point is set to the current (after change) supine position. The position is changed to the position on the prone position observation path PT2 corresponding to the reference point (# 30). The threshold value may be a value given in advance by a setting file, a program start parameter, user input, or the like.

FIG. 11 schematically shows how each reference point is changed in the second embodiment of the present invention. As shown in the figure, when the supine position reference point is located at the position RP1 _K, prone position reference point, and was in a position of RP2 _M corresponding to the position RP1 _K supine reference point. At this time, the supine position observation image I1 _K and the prone position observation image I2 _M are displayed on the display. When the first reference point changing unit 36 receives an operation of changing the supine position reference point from RP1 _K to RP1 _{K + 1} , the cumulative displacement amount of the supine position reference point is represented by d _{K + 1} in the drawing. Here, since the accumulated displacement amount d _{K + 1} is smaller than a predetermined threshold value, the position of the prone position the reference point is not changed remains RP2 _M. As a result, the supine position observation image is updated from I1 _K to I1 _{K + 1} , but the prone position observation image is not updated as I2 _M. Furthermore, when the position of the supine position reference point is sequentially changed, the display of the supine position observation image is referred to as I1 _{K + 2} , I1 _{K + 3} ... According to the position of the supine position reference point after the change. As long as the accumulated displacements d _{K + 2} , d _{K + 3} ... Of the supine position reference point are smaller than a predetermined threshold (from the supine position reference points RP1 _K to RP1 _{K + in} FIG. 11). _The corresponding prone position reference point remains unchanged at RP2 _M , and the prone position observation image remains unchanged at I2 _M.

When the position of the supine position reference point is changed to RP1 _{K + P} , the cumulative displacement amount d _{K + P of} the supine position reference point becomes equal to or greater than a predetermined threshold value. Therefore, the second reference point changing unit 37 changes the position of the prone position reference point from RP2 _M to the position RP2 _{M + 1} corresponding to the supine position reference point RP1 _{K + P.} Accordingly, the observation image I1 _{K + P} based on the supine position reference point RP1 _{K + P} is generated and the display is updated, and the prone position observation image I2 based on the prone position reference point RP2 _{M + 1} is also generated. _{M + 1} is generated, the display of the prone position observation image display is updated from I2 _M to I2 _{M + 1.}

  Thus, also in the second embodiment of the present invention, the second reference point changing unit 37 determines the position of the prone position reference point when the cumulative displacement amount of the supine position reference point is smaller than the predetermined threshold. The prone position reference point is changed to a position corresponding to the changed supine position reference point only when the accumulated displacement of the supine position reference point is equal to or greater than a predetermined threshold. It is possible to associate the reference point and the prone position reference point in a many-to-one relationship, and the same effect as in the first embodiment can be obtained.

  Each of the above embodiments is merely an example, and all of the above description should not be used to limit the technical scope of the present invention. In addition, the system configuration, the hardware configuration, the processing flow, the module configuration, the user interface, the specific processing content, etc. in the above embodiment have been variously modified without departing from the spirit of the present invention. It is included in the technical scope of the present invention.

  For example, in each of the embodiments described above, the user changes the supine position reference point, and the prone position reference point is changed according to the amount of displacement of the supine position reference point. The position reference point may be changed. In addition, it is configured so that the user can change either the supine position reference point or the prone position reference point, and when one of the reference points is changed, it is changed by the user according to the amount of displacement. The other reference point may be changed so that the one reference point and the other reference point have a many-to-one correspondence.

  In each of the above embodiments, the second reference point changing unit 37 performs the determination of step # 10 of FIG. 3 and step # 29 of FIG. 10, but the first reference point changing unit 36 performs this determination. Only when it is determined that the prone position reference point needs to be changed (steps # 10, # 29; YES), the second reference point changing unit 37 may be requested to change the prone position reference point. .

  In each of the above embodiments, each observation image is generated according to the change of each reference point, but the supine position reference point and the prone position reference point are in a many-to-one correspondence as described above. It may be set in advance along each observation path, and an observation image at each reference point may be generated in advance. In this case, steps # 8 and # 12 in FIG. 3 are included in step # 5, steps # 27 and # 31 in FIG. 10 are included in step # 24, and each reference point is changed. Only the display of the corresponding observation image is updated.

  In addition, the target images for comparative observation may be a plurality of different medical images obtained in a photographing position other than the supine position and the prone position. Or imaging conditions such as tube voltage and tube current in X-ray CT, imaging methods such as flare method and spin echo method in MRI, echo time (TE), repetition time (TR), etc. A plurality of medical images having different conditions, imaging protocols for obtaining T1-weighted images and T2-weighted images, imaging sequences, and the like may be used. Furthermore, it may be a plurality of medical images obtained by photographing at different times or a plurality of medical images having different contrast phases.

  The target for comparative observation may be a part other than the large intestine, for example, a luminal structure such as the small intestine, blood vessel, and bronchus, or a structure that exists in pairs such as the lung and kidney. For example, in the case of comparative observation of lumen structures having branches such as pulmonary blood vessels and bronchi, it is conceivable that the observation path dividing unit 32 divides the observation path block for each branch. 12A and 12B schematically show the cases where the blood vessels of the left lung and the right lung are divided into observation path blocks PT1 [1] to PT1 [9] and PT2 [1] to PT2 [9], respectively. is there. Note that the information for identifying each observation path block and the information indicating the positional range of each observation path block may be handled as tree structure data representing a branching structure. In this way, if the observation path is divided into a plurality of blocks by paying attention to the anatomical structure such as branching of the lumen structure, the change in the reference point in one image causes the change in the other image. It is possible to change the reference point in an anatomically meaningful unit, and comparative observation that matches the intention of the observer is possible.

  The observation image generated by the observation image generation unit 34 is based on an arbitrary cross section passing through the reference point, such as an image representing a cross section orthogonal to the tangent line of the observation path at the reference point or an image of three orthogonal cross sections passing through the reference point. It may be a two-dimensional cross-sectional image. Such a cross-sectional image can be generated using a known MPR technique. In addition, the luminal structure is cut by a curved surface along a given range of observation path, the luminal structure is stretched linearly, and a longitudinal cross-sectional image showing the inner wall side of the luminal structure is viewed, and the observation path It may be a developed image representing a state in which the lumen structure is cut open by a line parallel to the line, the lumen structure is straightened, and the inner wall side is developed. In this case, the reference point may correspond to the center position of the cross-sectional image or the developed image. The longitudinal cross-sectional image has a plurality of viewpoints starting from each of a plurality of viewpoints on the curved surface passing through the observation path, forming a predetermined angle with a tangent at the starting point of the curved surface, and moving toward a peripheral direction on one side of the curved surface. For each line-of-sight vector, using the image information on the line-of-sight vector, the pixel value of the projection pixel on which the lumen structure on the line-of-sight vector is projected is determined, and the alignment order of each viewpoint is maintained. Each can be generated by placing them on the projection plane (for details, refer to JP 2008-259713 A). In addition, for each of a plurality of viewpoints on a curved line serving as an observation path, the developed image has a line-of-sight vector for each of a plurality of line-of-sight vectors having a predetermined angle with a tangent to the curve at the starting point. Using the image information, the pixel value of the projection pixel on which the lumen structure on the line-of-sight vector is projected is determined, and the arrangement order of each viewpoint and the arrangement order of a plurality of line-of-sight vectors at each viewpoint are maintained. Each of the projection pixels can be generated by arranging them on the projection plane (for details, refer to the above-mentioned JP-A-2008-259713).

  In the configuration of FIG. 1, a plurality of image processing workstations 3 may be configured, and processing may be shared by each workstation.

DESCRIPTION OF SYMBOLS 1 Modality 2 Image storage server 3 Image processing workstation 9 Network 31 Observation path setting part 32 Observation path division part 33 Reference point setting part 34 Observation image generation part 35 Display control part 36 1st reference point change part 37 2nd reference point change Part

Claims (11)

A first observation path is set for the first three-dimensional medical image, and the first three-dimensional medical image is compared with the first three-dimensional medical image. Observation path setting means for setting a second observation path corresponding to the observation path;
A reference point setting means for setting a first reference point in the first observation path and setting a second reference point corresponding to the first reference point in the second observation path;
Means for displaying on the display means an observation image obtained from the three-dimensional medical image, passing through the reference point, or viewed from the reference point, the first three-dimensional medical image being obtained from the first three-dimensional medical image; Display control for displaying the first observation image based on the second reference point and the second observation image based on the second reference point obtained from the second three-dimensional medical image in a comparable manner Means,
First reference point changing means for changing a position of the first reference point in the first observation path;
If the displacement of the first reference point before and after the change is small enough not to satisfy the predetermined second reference point change condition, the position of the second reference point is not changed, and the displacement is A second reference point changing means for changing the second reference point to a position corresponding to the first reference point after the change if the second reference point change condition is large enough to satisfy the second reference point change condition; Prepared,
The display control means updates the display of the first observation image based on the first reference point before the change to the first observation image based on the first reference point after the change, When the position of the second reference point is changed, the display of the second observation image based on the second reference point before the change is displayed based on the second reference point after the change. A medical image diagnosis support apparatus that is updated to a second observation image. Observation path dividing means for dividing each of the first and second observation paths into a plurality of corresponding blocks;
The reference point setting means corresponds to the block to which the first reference point belongs, regardless of where the first reference point is set in any position in the block on the first observation path. A predetermined one of the second reference points in the block in the second observation path to be set,
The second reference point change condition is a condition that the block to which the first reference point before and after the change is different,
When the displacement satisfies the second reference point change condition, the second reference point changing means corresponds the second reference point to the block to which the changed first reference point belongs. The medical image diagnosis support apparatus according to claim 1, wherein the medical image diagnosis support apparatus is changed to a predetermined position in the block in the second observation path.   The medical image diagnosis according to claim 2, wherein the observation path dividing unit divides the observation path into the plurality of blocks based on an anatomical classification of an observation target represented in the three-dimensional medical image. Support device. Each of the three-dimensional medical images is an image showing a branch structure of a subject,
The observation path setting means sets the first and second observation paths along the branch structure;
The medical image diagnosis support apparatus according to claim 3, wherein the observation path dividing unit is configured to divide the plurality of blocks in a branch unit of the branch structure.   The medical image diagnosis support apparatus according to claim 2, wherein the observation path dividing unit obtains the plurality of blocks by dividing the entire length of the observation path at equal intervals.   3. The observation path dividing unit obtains the plurality of blocks by dividing the observation path by a given length from a start point or an end point of the observation path. The medical image diagnosis support apparatus according to 1.   The medical image diagnosis support according to claim 1, wherein the second reference point changing condition is a condition that a displacement amount of the first reference point before and after the change is larger than a predetermined threshold. apparatus. Each of the three-dimensional medical images is an image showing a lumen structure of a subject,
The medical image according to any one of claims 1 to 7, wherein the observation path setting means sets the first and second observation paths along the lumen structure. Diagnosis support device. Each of the three-dimensional medical images represents at least a part of the large intestine,
The first three-dimensional medical image is obtained by photographing with a supine posture,
The second three-dimensional medical image is acquired by photographing with a prone posture,
8. The observation path setting means is for setting the first and second observation paths along at least a part of the large intestine. The medical image diagnosis support apparatus according to the item. A first observation path is set for the first three-dimensional medical image, and the first three-dimensional medical image is compared with the first three-dimensional medical image. Setting a second observation path corresponding to the observation path;
Setting a first reference point in the first observation path and setting a second reference point corresponding to the first reference point in the second observation path;
A step of displaying an observation image obtained from the three-dimensional medical image, passing through the reference point or viewed from the reference point on a display means, the first three-dimensional medical image being obtained from the first three-dimensional medical image; Displaying a first observation image based on the second reference point and a second observation image based on the second reference point obtained from the second three-dimensional medical image in a comparable manner; ,
Changing the position of the first reference point in the first observation path;
If the displacement of the first reference point before and after the change is small enough not to satisfy the predetermined second reference point change condition, the position of the second reference point is not changed, and the displacement is If the second reference point change condition is large enough to satisfy the second reference point change condition, the step of changing the second reference point to a position corresponding to the first reference point after the change;
Updating the display of the first observation image based on the first reference point before the change to the first observation image based on the first reference point after the change, and the second reference point Is changed to display the second observation image based on the second reference point before the change on the second observation image based on the second reference point after the change. And a medical image diagnosis support method comprising the steps of: Computer
A first observation path is set for the first three-dimensional medical image, and the first three-dimensional medical image is compared with the first three-dimensional medical image. Observation path setting means for setting a second observation path corresponding to the observation path;
A reference point setting means for setting a first reference point in the first observation path and setting a second reference point corresponding to the first reference point in the second observation path;
Means for displaying on the display means an observation image obtained from the three-dimensional medical image, passing through the reference point, or viewed from the reference point, the first three-dimensional medical image being obtained from the first three-dimensional medical image; Display control for displaying the first observation image based on the second reference point and the second observation image based on the second reference point obtained from the second three-dimensional medical image in a comparable manner Means,
First reference point changing means for changing a position of the first reference point in the first observation path;
If the displacement of the first reference point before and after the change is small enough not to satisfy the predetermined second reference point change condition, the position of the second reference point is not changed, and the displacement is When it is large enough to satisfy the second reference point change condition, the second reference point changes as a second reference point changing means for changing the second reference point to a position corresponding to the changed first reference point. As well as
The display control means updates the display of the first observation image based on the first reference point before the change to the first observation image based on the first reference point after the change, When the position of the second reference point is changed, the display of the second observation image based on the second reference point before the change is displayed based on the second reference point after the change. A medical image diagnosis support program which functions to be updated to a second observation image.