JP2011095796A - Image processing apparatus, method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To readily create and provide a second two-dimensional image which is suitable for the comparative image interpretation with a first two-dimensional image, such as an MPR image. <P>SOLUTION: The image processing apparatus is configured to, in the case of creating a second two-dimensional image to be compared with a first two-dimensional image created under prescribed creation conditions from a first three-dimensional image reconfigured, by using a plurality of fault images from a second three-dimensional image obtained by retrieving a plurality of three-dimensional images recorded in a database; to set the retrieval conditions of the second three-dimensional image based on the generation conditions of the first three-dimensional image; and to retrieve the second three-dimensional image from a database, by using the set retrieval conditions and creating a second two-dimensional image under the prescribed creation conditions from the retrieved second three-dimensional image. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention is an image created from a three-dimensional image obtained by searching a plurality of three-dimensional images recorded in a database for a two-dimensional image to be compared with a two-dimensional image such as MPR created from the three-dimensional image. The present invention relates to a processing apparatus and method, and a computer program for carrying out the method.

  Conventionally, it is known to perform comparative interpretation using a past image and a current image of the same subject, and to observe and diagnose a change with time of a lesion. In this comparative interpretation, image processing such as alignment is performed so that the image characteristics match between the images to be compared, thereby making it easy to observe changes with time of the lesion.

  In particular, in the case where the past image is a two-dimensional image created from a three-dimensional image made up of a plurality of tomographic images obtained by photographing a subject, such as an MPR image, the current image having the same image characteristics is created. Capture multiple tomographic images under the same imaging conditions as when acquiring images, and create MPR images from the three-dimensional images made up of those tomographic images under the same image creation conditions as when acquiring past images. It has been known.

  In Patent Document 1, when an MPR image is generated from a three-dimensional image arbitrarily designated by an operator and displayed, a plurality of three-dimensional images obtained by continuously photographing the same subject region as the designated three-dimensional image are disclosed. It has been proposed to acquire images, calculate functional information such as metabolism and movement of organs from these three-dimensional images, and color MPR images according to the functional information.

JP 2006-75390 A

  By the way, for example, a lesion found for the first time in this examination is a two-dimensional image created from a three-dimensional image composed of a plurality of tomographic images obtained by photographing a subject, such as an MPR image, as an image most suitable for observation of the lesion. When observing, it may be desired to obtain and display a past image having similar image characteristics for comparative interpretation.

  However, as described above, the current comparison image with respect to the past image such as MPR can be easily obtained by taking a new image under the same photographing conditions as when the past image was obtained, and applying the same image creation conditions. Although it is possible to display past comparison images with respect to the current image, if there are no images such as MPR created under the same shooting conditions and the same image creation conditions in the database of images acquired in the past, acquisition and Display is not easy.

  In addition, even if a comparison image such as MPR is created using past image data in the database, when a large number of inspections are performed on the same subject and a large number of three-dimensional images are recorded in the database, It is not easy to determine which three-dimensional image is the most suitable for generating a comparison image.

  In addition, although patent document 1 mentions the point which searches automatically the three-dimensional image by which the same site | part of the same subject was image | photographed from a storage part as a process for acquiring function information, the details of the automatic search There is no mention of any method.

  In view of the above circumstances, an object of the present invention is to provide an image processing apparatus, method, and program that can easily create a two-dimensional image to be compared with a two-dimensional image such as an MPR from an existing database. .

  An image processing apparatus according to the present invention provides a second two-dimensional image to be compared with a first two-dimensional image created under a predetermined creation condition from a first three-dimensional image reconstructed using a plurality of tomographic images. Is generated from a second three-dimensional image obtained by searching from a plurality of three-dimensional images recorded in the database, and the second three-dimensional image is generated based on the first three-dimensional image generation condition. Search condition setting means for setting an image search condition, image search means for searching for a second three-dimensional image from the database using the set search condition, and second 3 searched by the image search means An image creating means for creating a second two-dimensional image from the two-dimensional image according to the predetermined creation condition is provided.

  Here, the three-dimensional image generation condition means a wide range of conditions related to various processes performed up to the three-dimensional image, and is used for, for example, reconstruction of the three-dimensional image. Meaning the type of modality used to capture multiple tomographic images, the slice interval of the tomographic image, the direction in which the tomographic image continues, and the image processing applied to the tomographic image and / or the three-dimensional image It is.

  In addition, the second 3D image retrieved from the database is not limited to the 3D image itself, and a tomographic image that can be substantially identical to the 3D image, such as a 3D image can be immediately formed by reconstruction. It also means a group widely.

  In the above apparatus, the search condition may be that the generation condition of the second three-dimensional image is within a predetermined range from the generation condition of the first three-dimensional image.

  Here, the fact that the second 3D image generation condition is within a predetermined range from the first 3D image generation condition means that each of the items constituting the second 3D image generation condition is the first This means that the generation conditions of the same item of the three-dimensional image coincide with each other or differ within a predetermined range. For example, as a generation condition of the first three-dimensional image, the type of modality used for photographing a plurality of tomographic images constituting the first three-dimensional image is CT, and the slice interval of the tomographic image is 0.5 mm. In this case, the search condition setting means is that the type of modality used for photographing the plurality of tomographic images used for the reconstruction of the second three-dimensional image is CT, and the slice interval of the tomographic image is from 0.5 mm. It can be set as a search condition that it is within a range of 0.2 to 0.8 mm within ± 0.3 mm.

  In the above apparatus, the search condition may include that the second three-dimensional image has an image range common to the first three-dimensional image.

  Here, having an image range common to the first three-dimensional image means having an image range in which the same or the same type of subject as the subject photographed in the first three-dimensional image is photographed. This means that not only the case where the same part of the same patient has an image range photographed but also the case where another patient has an image range obtained by photographing the same part is included.

  In addition, the first two-dimensional image may have a target position set on the image, and the search condition may include that the second three-dimensional image has a portion corresponding to the target position.

  In the case where there are a plurality of the searched second 3D images, the apparatus is configured to select a plurality of second 3D images based on the degree to which the generation conditions of each image match the generation conditions of the first 3D image. The image processing apparatus may further include a selection unit that selects any one of the two three-dimensional images.

  The first and second two-dimensional images may be any of a Multi-Planar Reconstruction image, a Maximum Intensity Projection image, a Minimum Intensity Projection image, and a Volume Rendering image.

  The apparatus may include an image display unit that displays the second two-dimensional image created by the image creation unit.

  The apparatus further includes an input means for inputting an instruction for setting or changing a search condition, and the search condition setting means further has a function for setting or changing the search condition in accordance with the instruction input by the input means. It may be.

  An image processing method according to the present invention provides a second two-dimensional image to be compared with a first two-dimensional image created under a predetermined creation condition from a first three-dimensional image reconstructed using a plurality of tomographic images. Is generated from a second three-dimensional image obtained by searching from a plurality of three-dimensional images recorded in the database, and the second three-dimensional image is generated based on the first three-dimensional image generation condition. A step of setting a search condition for an image, a step of searching for a second 3D image from the database using the set search condition, and the predetermined creation from the searched second 3D image And a step of creating a second two-dimensional image according to conditions.

  The lesion area extraction program of the present invention is a program that causes a computer to function as search condition setting means, image search means, and image creation means in the image processing apparatus.

  This program is recorded on a recording medium such as a CD-ROM or DVD, or is recorded in a downloadable state on a built-in disk or network storage of a server computer and provided to the user.

  According to the image processing apparatus, method, and program of the present invention, it should be compared with a first two-dimensional image created according to predetermined creation conditions from a first three-dimensional image reconstructed using a plurality of tomographic images. When the second two-dimensional image is created from the second three-dimensional image obtained by searching from a plurality of three-dimensional images recorded in the database, the second two-dimensional image is generated based on the first three-dimensional image generation condition. 2 is set, a second 3D image is searched from the database using the set search condition, and the second 3D image is searched from the searched second 3D image according to the predetermined creation condition. Since a two-dimensional image is created, a three-dimensional image having a predetermined relationship between image characteristics based on the first three-dimensional image and its generation condition is selected from a plurality of three-dimensional images recorded in the database. As a two-dimensional image You can obtain, easily create and provide a second two-dimensional image suitable for comparative reading of the first two-dimensional image.

  In the above apparatus, when the search condition includes that the second three-dimensional image has an image range common to the first three-dimensional image, a two-dimensional image suitable for comparative interpretation is more reliably generated.・ Can be provided. In the medical field, depending on the type of subject, there is a tendency to set conditions such as the type of modality used for imaging and the slice interval of tomographic images, so even if these conditions are the same three-dimensional image. In many cases, it is considered that the same subject is photographed, and two-dimensional images created from these three-dimensional images under the same creation conditions can be directly subjected to comparative interpretation. However, since different subjects may be photographed even in the three-dimensional images generated under the same conditions, in such a case, as described above, an image common to the first three-dimensional image is used. By including that there is a range in the search conditions for the second three-dimensional image, an effect is obtained that a two-dimensional image suitable for comparative interpretation can be more reliably created and provided.

1 is a schematic configuration diagram showing an embodiment of an image processing apparatus of the present invention. The flowchart which shows an example of the process performed by the image processing apparatus of FIG. Figure showing an example of the display screen

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of an image processing apparatus 1 according to an embodiment of the present invention.

  The image processing apparatus 1 records various image data generated in each examination performed on the same subject in a database, and an MPR image, MIP image, When a first two-dimensional image such as a minIP image or VR image is designated as a target for comparative interpretation, the second two-dimensional to be compared with the designated first two-dimensional image using the database. Acquire and provide images.

  The image processing apparatus 1 includes a CPU 2, a memory 3, a hard disk 4, and a communication port 5 as a standard computer configuration. The image processing apparatus 1 also includes a display 6 and an input device such as a mouse 7. The image processing apparatus 1 is connected in a communicable state with a modality such as a CT apparatus or an MRI apparatus, or an interpretation report creating apparatus that creates an electronic interpretation report regarding a medical image in accordance with a user input operation. Yes.

  The memory 3 stores an image processing program. The image processing program defines a two-dimensional image search process, a search condition setting process, a three-dimensional image search process, an image selection process, an image creation process, an image display process, and the like as processes to be executed by the CPU 2. The general-purpose computer functions as a two-dimensional image search means, a search condition setting means, a three-dimensional image search means, a selection means, an image creation means, and an image display means by the CPU 2 executing these processes according to the program. Will do.

  The hard disk 4 stores various types of image data generated in each inspection and accompanying information, an interpretation report created by the interpretation report creation device, and the like. In the image processing apparatus 1, a database is constructed so that desired image data can be searched and used for various image data recorded on the hard disk 4.

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

  Next, specific processing performed in the image processing apparatus 1 will be described with reference to the flowchart of FIG. Here, in order to facilitate understanding, the current MPR image created in the current examination among the multiple examinations performed on the same subject is designated as the target of comparative interpretation and is designated as such. This will be described assuming that the previous MPR image to be compared with the current MPR image is acquired and provided.

  First, the image processing apparatus 1 executes a two-dimensional image search process ST1 for searching for a desired two-dimensional image itself from the database. Specifically, an MPR image representing a cross section substantially the same as the current MPR image is searched from a database of image data generated in the previous examination. Whether or not the MPR image represents the substantially same cross section as the current MPR image is determined by determining whether or not the position and direction of the cross section with respect to the subject coincide with the current MPR image. In this determination, it is determined that not only the position and direction of the cross section completely match, but also that the difference is within a predetermined allowable range.

For example, if the image orientation vector of this MPR image (Image Orientation in the DICOM standard) is Ax, Ay, and the image orientation vector of the MPR image to be judged is Bx, By, the image direction vector Bx, By is When any of the following requirements (1) to (3) is satisfied, it is determined that the MPR image has the same cross-sectional direction as the current MPR image. Here, Ax, Ay and Bx, By are three-dimensional vectors in the human body coordinate system.
(1) The inner product of Ax and Bx is less than the predetermined value, and the inner product of Ay and By is less than the predetermined value
(2) The absolute value of the inner product of Ax and Bx is less than the specified value
(3) When the outer product of Ax and Ay is An and the outer product of Bx and By is Bn, the inner product of An and Bn (or its absolute value) is less than the specified value.

  In addition, when the image position vector of this MPR image (Image Position in DICOM standard) is Ap and the image position vector of the MPR image to be judged is Bp, the absolute value of the difference between Ap and Bp (Ap and When the Bp distance is equal to or less than a predetermined value, it is determined that the MPR image matches the position of the cross section with the current MPR image. Here, Ap and Bp are three-dimensional vectors in the human body coordinate system.

  In addition, although the case where the MPR image is searched in the two-dimensional image search processing ST1 has been described here, the image specified as the target of the comparative interpretation is another type of image such as a MIP image, a minIP image, or a VR image. In this case, the above-described determination method is not applied as it is, but the search process is performed by a determination method corresponding to the type. For example, when an MIP image is designated as a target for comparative interpretation, a MIP image in which conditions such as the viewpoint of projection processing and the projection direction match within a predetermined allowable range is searched.

  When a desired MPR image is found from the database by the above two-dimensional image search process ST1, the image processing apparatus 1 acquires the MPR image and displays it on the screen of the display 6 together with the current MPR image. To provide. On the other hand, if not found, the search condition setting process ST2 is continuously executed.

  In the search condition setting process ST2, the image processing apparatus 1 sets a search condition for searching an original image used for creating a desired two-dimensional image from the database. Specifically, the generation conditions of the first three-dimensional image used to create the current MPR image are acquired, and the previous MPR image to be compared with the current MPR image is created based on the generation conditions. The search condition for the second three-dimensional image used in the above is set.

  For example, first, as a generation condition of the first three-dimensional image, the type of modality used for photographing a plurality of tomographic images used for reconstruction of the first three-dimensional image, the slice interval of the tomographic image, The direction in which the tomographic image continues, image processing applied to the tomographic image and / or the first three-dimensional image, and the like are acquired. Since the MPR image is accompanied by information (image ID, series ID, etc.) for specifying the original image used to create the image, the first 3 with reference to the accompanying information of the current MPR image The generation condition as described above may be acquired by specifying the three-dimensional image and further referring to the incidental information of the specified first three-dimensional image. Next, the obtained generation conditions for each item are directly set as search conditions for the second three-dimensional image.

  As a specific example, the first three-dimensional image is that the modality is a CT apparatus, the slice interval of a tomographic image is 0.5 mm, the direction in which cross-sectional images are continuous is an axial direction, and lung field filtering is performed as image processing. When the acquisition condition is acquired, the modality used for imaging a plurality of tomographic images used for reconstruction of the second three-dimensional image is used as a search condition for the second three-dimensional image. Yes, the slice interval of the tomographic image is 0.5 mm, the direction in which the tomographic images continue is the axial direction, and the tomographic image and / or the first three-dimensional image has been subjected to lung field filtering. Can be set.

  Here, as a method of setting conditions in the search condition setting process ST2, a case has been described in which the generation condition of the second three-dimensional image matches the generation condition of the first three-dimensional image. It may be set as a search condition that the generation condition of the second three-dimensional image is within a predetermined range from the generation condition of the first three-dimensional image.

  As a specific example, the first three-dimensional image is that the modality is a CT apparatus, the slice interval of a tomographic image is 0.5 mm, the direction in which cross-sectional images are continuous is an axial direction, and lung field filtering is performed as image processing. If the modalities used for imaging a plurality of tomographic images used for reconstruction of the second 3D image are used as the search conditions for the second 3D image, the CT apparatus or The slice interval of the tomographic image is within a range of 0.2 to 0.8 mm in the range of 0.5 mm to ± 0.3 mm, and the direction in which the tomographic image continues is the axial direction, and the tomographic image and / or the first It can be set that the three-dimensional image is subjected to lung field filtering.

  Note that when the slice interval condition is set as described above, the upper limit can be set to 2 mm. The reason why the thickness is 2 mm is that the slice interval of the tomographic image is required to be 2 mm or less in order to create an MPR image, MIP image, or the like with high image quality.

  In addition, as a method of setting conditions in the search condition setting process ST2, for example, the degree to which the generation conditions of the second 3D image coincide with the generation conditions of the first 3D image in each item is evaluated. An evaluation value may be calculated, and it may be set as a search condition that the sum of these evaluation values is equal to or greater than a predetermined threshold value. In this case, it is preferable to appropriately set a weighting factor for each item of the generation condition according to the use and purpose of comparative interpretation.

  In the search condition setting process ST2, in addition to the above conditions, for example, it can be set as a search condition that the second three-dimensional image has an image range common to the first three-dimensional image. Note that the determination of whether or not they have a common image range is performed by, for example, performing alignment using the alignment method described in Japanese Patent Application Laid-Open No. 2007-68554 and determining whether or not there is an overlapping portion. This can be done by judging.

  For example, when the position of the lesion area on the first two-dimensional image is set as the attention position, the second three-dimensional image is searched for having a portion corresponding to the attention position. It can also be set as a condition.

  The image processing apparatus 1 further has a function of displaying a search condition creation screen on the display 6 and setting the search condition in accordance with a user input operation on the creation screen. For example, when the search condition set by the above-described method is displayed on the creation screen and the user inputs an instruction to change the displayed search condition with a mouse or a keyboard, the search condition is updated according to the input. To do. Search conditions are displayed as a combination of multiple condition items, and the user can arbitrarily add / delete condition items to the displayed search conditions, and further set / change the contents of each condition item. Can do. Alternatively, some search condition patterns corresponding to the use and purpose of comparative interpretation may be registered in advance, and a pattern selected by the user may be set as a search condition in the current search process.

  Subsequently, the image processing apparatus 1 executes a 3D image search process ST3 for searching for a second 3D image from the database using the search condition set by the search condition setting process ST2, and satisfies the search condition. A second three-dimensional image is acquired.

  If there is a single second 3D image retrieved by this 3D image retrieval process ST3, then in the image creation process ST5, a second 2D image is extracted from the retrieved second 3D image. Processing to create is performed. On the other hand, if there are a plurality of images, a selection for selecting one of the plurality of second three-dimensional images based on the degree to which the generation conditions of each image coincide with the generation conditions of the first three-dimensional image. Processing ST4 is further performed. In image creation processing ST5, processing for creating a second two-dimensional image from the selected second three-dimensional image is performed.

  In the selection process ST4, for each of the plurality of searched second 3D images, the degree to which the image generation conditions match the first 3D image generation conditions in each item, and the common image range An evaluation value that evaluates the size, the presence / absence of a portion corresponding to the position of interest, and the like are calculated, and the one having the largest sum of the evaluation values is selected. In this case, a weighting factor may be set as appropriate for each evaluation item. Thereby, for example, it is possible to preferentially select an image whose slice interval is close to that of the first three-dimensional image, or to preferentially select an image having a large common image range.

  In the image creation process ST5, by referring to the incidental information of the current MPR image, the creation conditions used to create the image are acquired, and the creation conditions are applied to the searched second three-dimensional image. Create MPR images.

  Finally, the image processing apparatus 1 executes an image display process ST6 for displaying the current MPR image created in the image creation process ST5 on the screen of the display 6. For example, as shown in FIG. 3, the previous MPR image 81 and the current MPR image 82 created in the image creation process ST5 are displayed side by side on the screen 61 of the display 6.

  As described above, according to the image processing apparatus and program of the present embodiment, the first two-dimensional image created under the predetermined creation condition from the first three-dimensional image reconstructed using a plurality of tomographic images. When the second two-dimensional image to be compared with the second three-dimensional image obtained by searching from a plurality of three-dimensional images recorded in the database is generated, The second 3D image search condition is set based on the second search result, the second 3D image is searched from the database using the set search condition, and the second predetermined 3D image is searched from the searched second 3D image. Since the second two-dimensional image is created according to the creation conditions, the first three-dimensional image and the image characteristics based on the generation conditions thereof are in a predetermined relationship from the plurality of three-dimensional images recorded in the database. A two-dimensional image with a second three-dimensional image Acquisition Te can be easily created and provide a second two-dimensional image suitable for comparative reading of the first two-dimensional image.

  In the above-described embodiment, a case where a past image to be compared with the current image is obtained and provided from the database of image data generated in the previous examination is described as an example. However, the present invention is not limited to the previous examination. Alternatively, it may be obtained and provided from a database of image data generated in a plurality of past examinations. Further, until a past image suitable for comparative interpretation is retrieved, the image retrieval may be executed sequentially in the past, such as the previous inspection, the previous inspection, and the previous inspection.

  In the above embodiment, when there are a plurality of second 3D images searched by the 3D image search process ST3, the selection process ST4 for automatically selecting one of them is executed, and the selection is performed in the selection process ST4. In the above description, the second 2D image is created only from the second 2D image thus obtained. For example, the second 2D image is created from each of the plurality of second 3D images searched. A plurality of the created second two-dimensional images can be displayed as a list on the screen of the display 6, and the user can select an image to be used for comparative interpretation.

1 Image processing device 2 CPU
3 Memory 4 Hard disk 5 Communication port 6 Display 7 Mouse
81 This MPR image
82 Previous MPR image

Claims (10)

A plurality of second 2D images to be compared with a first 2D image created under a predetermined creation condition from a first 3D image reconstructed using a plurality of tomographic images are recorded in a database. An image processing apparatus that creates a second three-dimensional image obtained by searching from a three-dimensional image of
Search condition setting means for setting search conditions for the second three-dimensional image based on the generation conditions for the first three-dimensional image;
Image search means for searching for a second three-dimensional image from the database using the set search condition;
An image processing apparatus comprising: an image creating unit that creates the second two-dimensional image from the second three-dimensional image retrieved by the image retrieval unit according to the predetermined creation condition.   The image processing apparatus according to claim 1, wherein the search condition is that the generation condition of the second three-dimensional image is within a predetermined range from the generation condition of the first three-dimensional image.   3. The image processing apparatus according to claim 2, wherein the search condition includes that the second three-dimensional image has an image range common to the first three-dimensional image. The first two-dimensional image has an attention position set on the image,
4. The image processing apparatus according to claim 2, wherein the search condition includes that the second three-dimensional image has a portion corresponding to the target position.   When there are a plurality of the searched second 3D images, the plurality of second 3D images are determined based on the degree to which the generation conditions of the images match the generation conditions of the first 3D image. The image processing apparatus according to claim 2, further comprising selection means for selecting any one of the three-dimensional images.   The first and second two-dimensional images are any one of a Multi-Planar Reconstruction image, a Maximum Intensity Projection image, a Minimum Intensity Projection image, and a Volume Rendering image. The image processing apparatus according to item.   The image processing apparatus according to claim 1, further comprising an image display unit that displays a second two-dimensional image created by the image creation unit. An input means for inputting an instruction to set or change the search condition;
The search condition setting unit further has a function of setting or changing the search condition in accordance with an instruction input by the input unit. Image processing device. A plurality of second 2D images to be compared with a first 2D image created under a predetermined creation condition from a first 3D image reconstructed using a plurality of tomographic images are recorded in a database. An image processing method for creating from a second three-dimensional image obtained by searching from a three-dimensional image of
Setting search conditions for the second three-dimensional image based on the generation conditions for the first three-dimensional image;
Searching the database for a second 3D image using the set search condition;
And a step of creating the second two-dimensional image from the retrieved second three-dimensional image according to the predetermined creation condition. A computer records a second 2D image to be compared with a first 2D image created according to predetermined creation conditions from the first 3D image reconstructed using a plurality of tomographic images. A program for functioning as an image processing device that creates a second three-dimensional image obtained by searching from a plurality of three-dimensional images,
The computer,
Search condition setting means for setting search conditions for the second three-dimensional image based on the generation conditions for the first three-dimensional image;
Image search means for searching for a second three-dimensional image from the database using the set search condition;
An image processing program for functioning as an image creation unit that creates the second two-dimensional image from the second three-dimensional image retrieved by the image retrieval unit according to the predetermined creation condition.

Images