DE102012218416A1 - Method for automatic detection of tumor, involves determining course of cross-sections of hollow organ along center line, selecting area of hollow organ, determining characteristic of selected area, and assessing characteristic of area - Google Patents

Abstract

The method involves determining (B1) a course of cross-sections of the hollow organ along the center line, and selecting (A) an area of the hollow organ using the course of the cross-sections, where the area has a geometric characteristic of the tumor. A characteristic of the selected area is determined (B2). A portion of the three-dimensional reconstruction is registered (R) with another three-dimensional reconstruction of a portion of the hollow organ. The specific characteristic of the selected area is assessed (Bu) to determine whether it is in the selected area around the tumor. An independent claim is included for a system for automatic detection of a tumor.

Description

The invention relates to a method and a system for the automatic detection of a tumor.

Examination of patients for cancer screening also includes endoscopic procedures to examine hollow organs such as the intestine for tumors. Since endoscopy is perceived as unpleasant for many patients and also carries a risk of injury, imaging techniques and systems for virtual endoscopy have been developed in recent years. Virtual endoscopy is based on spatially-three-dimensional, in short 3D, imaging, for example by means of computed tomography, CT for short, or magnetic resonance tomography, MRT for short. There are various options available to create an image contrast, for example, the natural contrast between tissue and air can be used and / or a contrast agent can be used. Such methods of 3D imaging allow a distortion-free 3D reconstruction of the imaged volume. Virtual endoscopy allows the analysis of 3D reconstruction both by the physician and by image processing methods. For example, image processing methods may alert the physician to conspicuous areas. The virtual endoscopy of the intestine is also referred to as colonography and has now become a standard procedure. Part of image processing in colonography is the provision of a central line (also called the "centerline") along the course of the intestine. Such a central line is also referred to as the observer path along which the 3D reconstruction of the intestine is viewed. The central line thus represents the line along which the virtual endoscope head moves.

Out DE 10 2004 027 709 B4 For example, a method of virtual endoscopy for 3D medical imaging and 3D image processing is known. This method comprises providing a first evaluation volume based on a 3D data volume and providing a viewer path through the first evaluation volume. The method is characterized by an automatic determination of at least one further evaluation volume separated from the first evaluation volume on the basis of the 3D data volume according to predetermined criteria.

It is an object of the invention to simplify the detection of tumors in the context of virtual endoscopy.

The object is achieved by a method according to claim 1 and by a system according to claim 12.

The solution according to the invention will be described below with reference to the claimed system as well as with reference to the claimed method. Features, advantages or alternative embodiments mentioned herein are also to be applied to the other claimed subject matter and vice versa. In other words, the subject claims directed, for example, to a system may also be developed with the features described or claimed in connection with a method. The corresponding functional features of the method are formed by corresponding physical modules.

The invention is based on a 3D reconstruction of a hollow organ and on the provision of at least one central line of the hollow organ in the 3D reconstruction. The invention is based on the idea to determine the course of cross sections of the hollow organ along the central line and to select a region of the hollow organ by means of the profile of the cross sections, wherein the region has at least one geometric property of a tumor. The course of the cross sections of the hollow organ allows a precise determination of the geometric shape of the wall of the hollow organ and thus also of tumors growing on this wall. Since tumors in hollow organs have a characteristic shape, tumors can be relatively easily and accurately determined by their geometric properties. The selection of an area which has at least one geometric property of a tumor serves to further investigate the area and thus simplifies the detection of tumors.

The invention further comprises that the first determination of the course of cross sections takes place by means of cross-sectional areas of the hollow organ oriented substantially perpendicular to the central line. As soon as a 3D reconstruction of the hollow organ and a central line of the hollow organ are present, it is possible to calculate directly cross-sectional areas which are oriented substantially perpendicular to the central line. Such a cross-sectional line allows a direct determination of cross-sections along different axes through the central line within the cross-sectional area. Accordingly, the course of cross sections along the central line can be determined directly from the cross-sectional areas.

Furthermore, the invention comprises a second determination of at least one property of the selected region, wherein the property is suitable for the detection of a tumor. Because such a second determination makes it possible to test the selected region by means of a further property to see whether it is the selected one Area around a tumor. Thus, the second determination increases the reliability of a diagnosis based on the method of the invention.

Furthermore, the second determination in the method according to the invention may include the determination of the signal strength of the selected region. Because the signal strength can be an indication of a tumor in a reconstructed image, especially if contrast agents are used in the imaging.

In a further embodiment of the method, the second determination comprises the determination of at least one geometric property of the selected region. Because different geometric properties of a selected area can be used for diagnosis and for planning a further treatment.

Furthermore, the invention comprises the registration of at least part of the 3D reconstruction with a second 3D reconstruction of at least a part of the hollow organ. Because the information content of two 3D reconstructions can be checked for consistency by registering.

Furthermore, the invention comprises that the two 3D reconstructions are each based on images by means of different imaging modalities. Therefore, the first and second 3D reconstruction may contain complementary information so that further analysis steps based on the registered images may be made for the purpose of diagnosis.

Furthermore, the invention comprises that the second 3D reconstruction is based on a recording by means of positron emission tomography (PET), since PET is particularly well suited to identify tumors on the basis of their metabolic functions.

Furthermore, the invention includes that a method according to the aforementioned embodiments is also carried out based on the second 3D reconstruction, ie at least comprising a first determination of a course of cross sections of the hollow organ and a selection of a region of the hollow organ and optionally comprising a second determination at least one property of the selected area. The registration of two already analyzed 3D reconstructions allows to combine the information of the analysis. If, for example, the same area was selected in both 3D reconstructions and matching shapes of the area were determined, this indicates a correct selection or determination.

Furthermore, the method according to the invention comprises the assessment of the at least one specific property of the selected area as to whether the selected area is a tumor. Such an automatic assessment makes it easier for the treating person, for example a doctor, to make the final diagnosis.

Furthermore, the invention comprises a visual output of the reconstructed hollow organ as well as at least part of the information obtained in the individual steps of the method, whereby the information can be particularly easily perceived by a treating person, such as a doctor and interpreted for the purpose of diagnosis.

The system according to the invention furthermore comprises a determination unit designed for a first determination of a profile of cross sections of a hollow organ along a central line, based on a 3D reconstruction of the hollow organ and based on the provision of at least one central line of the hollow organ in the 3D reconstruction. The system further comprises a selection unit designed to select a region of the hollow organ by means of the profile of the cross sections, wherein the region has at least one geometric property of a tumor.

Furthermore, the invention comprises a determination unit which is designed for a second determination of at least one property of the selected area, the property being suitable for the detection of a tumor.

Furthermore, the invention comprises a registration unit designed to register at least one area of the 3D reconstruction with a second 3D reconstruction of at least one area of the hollow organ.

Furthermore, the invention comprises an output unit, designed for visual output of the reconstructed hollow organ as well as at least part of the information obtained in the individual steps of the method.

Furthermore, the system according to the invention comprises an assessment unit designed to assess the at least one specific property of the selected area in terms of whether the selected area is a tumor.

Furthermore, the invention comprises an image processing unit designed for 3D reconstruction of a hollow organ and for providing at least one central line of the hollow organ in the 3D reconstruction.

Furthermore, the invention comprises an imaging device designed to record tomographic data of a hollow organ, whereby the system according to the invention is developed into an integrated solution, which also fulfills the prerequisites for the reconstruction of a 3D reconstruction of the hollow organ.

The system according to the invention is designed to carry out the method steps according to the invention with the corresponding advantages.

Show it:

1 a flow chart of the method according to the invention,

2 a schematic representation of the course of the cross sections of a hollow organ,

3 a block diagram of the system according to the invention and

4 an extended system according to the invention.

1 shows a flow chart of the method according to the invention for the automatic detection of a tumor 5 , For the purposes of the present application is a tumor 5 a neoplasm, ie a new formation of tissue. Such neoplasm can be both benign and malignant. Examples of tumors 5 are polyps, sarcomas and carcinomas. The invention is based on a 3D reconstruction of a hollow organ 1 , In a hollow organ 1 it is an organ that encloses a cavity with its tissue. Examples of hollow organs 1 are the esophagus, the bronchial tree, the stomach as well as the intestine.

Such a 3D reconstruction requires the inclusion of the hollow organ 1 by means of an imaging method, typically a tomographic method such as MRI, CT or rotational angiography. The contrast in such an imaging method may be based on various mechanisms. For example, MRI essentially measures the relaxation time of atomic nuclei, particularly hydrogen nuclei, while in CT, essentially, the different X-ray absorption properties of different tissue types create a contrast. Thus, the colonography the intestinal typically is purified by administration of a laxative first and then filled in a CT image with a gas, such as CO _2, or at an MRI scan with water in the case, whereby a natural contrast between the tissue and the With gas or water filled cavity of the intestine arises. Furthermore, the filling with gas or water also serves the unfolding of the intestine.

Contrast agents can be used in both MRI and CT, especially to produce a specific contrast. Contrast agents are generally defined as those agents which improve the imaging of structures and functions of the body in imaging processes, for example by changing the X-ray absorption during a CT examination or the relaxation time in the context of an MRI examination. Usually, contrast media are distinguished from so-called tracers. This is an artificial, often radiolabeled endogenous or exogenous substance, which participates in the metabolism after introduction into the living body and enables or facilitates a variety of examinations. Tracers allow in particular the presentation of metabolic properties. In the context of the present application, contrast agents are to be understood as meaning both conventional contrast agents and tracers. When taking up hollow organs 1 Contrast agents can be injected intravenously to achieve a better contrast between the blood-perfused tissue and the (possibly filled with air or water) cavity. In colonography, an oral contrast agent may also be administered which allows unrecognized stool to be detected after 3D reconstruction and to be subtracted from the reconstructed image.

The 3D reconstruction of the hollow organ 1 extends beyond a mere reconstruction of the tomographic data set, for example in the context of a so-called "Filtered Back Projection" (FPB). The subsequent steps require that the boundary between the tissue of the hollow organ 1 and the internal cavity is detected. Such recognition takes place in the embodiment described here by segmentation. For example, the segmentation is performed by a threshold method or by a region-oriented method such as the so-called "region growing" or the so-called "region splitting" or by means of edge extraction. Furthermore, each of the following steps is visualized by means of the 3D reconstruction, which enables the treating person to understand and check the individual steps. Such visualization takes place for example by means of the so-called "Volume Rendering" (VR). In VR, several threshold regions, for example on the surface of the reconstructed gut, are defined and assigned to these colors and permeabilities. The virtual endoscopy aims to provide a perspective view of the near environment of the virtual endoscope head do. Structures, unlike the actual endoscope, can be viewed from different directions and moved. The 3D reconstruction thus includes, in particular, the reconstruction of a surface which extends into the 3D space, that is to say, for example, the surface of the intestinal wall which delimits the surrounding tissue from the cavity. Such a reconstructed surface is visualized, for example, by the so-called "Surface Shaded Display" technique.

An important prerequisite for carrying out the method according to the invention is the provision of a central line 2 of the hollow organ 1 in the 3D reconstruction. Because most of the hollow organs 1 As the esophagus, stomach and intestine are elongated, there is naturally a longitudinal axis along the central line 2 is oriented. The central line 2 This also corresponds to the path that an actual endoscope head would take during an endoscopic examination. Furthermore, the provision of a central line 2 Also include that different parts of a hollow organ 1 , which have been individually reconstructed, with each other through a common center line 2 be connected as in the prior art DE 10 2004 027 709 B4 is described.

At the beginning of the method according to the invention are cross sections of the hollow organ 1 certainly. The respective transverse axes along which the cross sections are measured are substantially perpendicular to the central line 2 oriented. In particular, the transverse axes, along which the cross sections are measured, intersect the center line 2 so that the cross sections are a measure of the diameter of the hollow organ 1 represent. In the first determination B1 of a course 4 of cross sections of the hollow organ 1 along the central line 2 The transverse axis, along which the individual cross sections are measured, typically has the same orientation. The first determination B1 of a course 4 of cross sections thus corresponds to the scanning of cross sections along the long extension of the hollow organ 1 , Furthermore, the first determination B1 comprises a course 4 From cross-sections, the determination of several profiles of cross sections. In other words, a first course 4 are based on cross sections measured along a first transverse axis, while a second course 4 may be based on cross-sections measured along a second transverse axis. The first determination B1 thus allows the determination of a profile of the inner surface of the hollow organ 1 , Furthermore, the first determination B1 of the course takes place 4 of cross sections by means substantially perpendicular to the center line 2 oriented cross-sectional areas 3 of the hollow organ 1 , Such cross-sectional areas 3 Thus, for example, be spanned by the aforementioned first and second axis. Within this cross-sectional area 3 Of course, further axes can be defined along which cross sections can be determined. The distance along the center line 2 , in which the individual cross sections are measured, is fundamentally arbitrary, but should be chosen so small that the geometric properties of a tumor 5 can be recognized. Parameters such as the distance along the center line 2 between the individual cross-sectional areas 3 can either be entered manually by an operator of a system designed to carry out the method. Alternatively, such parameters may be automatically selected, for example by selecting only a particular examination mode from the operator. The examination mode takes into account the imaging modality, the administration of contrast media and information about the patient, such as age and gender.

The selection A of a region of the hollow organ 1 by means of the course 4 the cross-sections, wherein the region at least one geometric property of a tumor 5 requires methods of pattern recognition. When selecting A, the history becomes 4 of cross sections based on at least one of the course 4 Extracted geometric property compared with such gradients (and the corresponding geometric property) that are related to a tumor 5 close. As it is in a tumor 5 is newly formed tissue, this protrudes from the uniform structure of the inner surface of the hollow organ 1 out. This is shown by tumors 5 in hollow organs 1 characteristic geometric properties, which are reflected for example in a reduced cross-section. The history 4 The cross sections are classified in the embodiment described here to be for a tumor 5 to be able to conclude on the basis of the classification. An example of a classification system is the so-called "TNM classification". The selection A of a range makes it possible to segment this range (using the already mentioned methods), which in turn simplifies further work steps or makes them possible in the first place.

An area selected for further analysis with the aim of detecting tumors 5 to simplify. The detection of tumors 5 is carried out both by the attending physician and by the system according to the invention, which is designed for carrying out the method according to the invention. To aid the diagnosis of a treating physician, the selected area in the visual output VA of the reconstructed hollow organ 1 marked. For example, the area may be displayed in a different color or otherwise highlighted. The visual output VA may also include that in the virtual "flight" through the hollow organ 1 Parameters such as the average, minimum and maximum cross section at a point of the centerline 2 The calculation of the statistical data is based on the determination of several cross-sections in a cross-sectional area 3 based on the central line 2 in the point cuts. The cross sections can also over larger areas, for example over ten cross-sectional areas 3 with a distance of one millimeter each, so that these averaged values are provided for visual output VA.

In a further step, a second determination B2 of at least one property of the selected region takes place, wherein the property for detecting a tumor 5 suitable is. For example, this property is the signal strength of the selected area. The signal strength can be determined in various reconstructions with different intensity scaling or windowing of the area. For example, the signal strength in the case of a CT scan is determined in values of the Houndsfield scale. The signal strength indicates when given intravenous contrast agents, whether the selected area is a tumor 5 This is because certain contrast agents are present in certain types of tumors 5 accumulate. Furthermore, in the second determination B2, at least one geometric property of the selected region is determined. Such a geometric property is, for example, the volume that is easily determined when following a segmentation of the selected area. Furthermore, information can be obtained from the combination of the geometric properties and the signal intensity. For example, the intensity distribution in a certain part of the tumor is evaluated by calculating and outputting a histogram of the intensity distribution.

Furthermore, the method according to the invention comprises a registration R of at least part of the 3D reconstruction with a second 3D reconstruction of at least part of the hollow organ 1 , For example, two CT scans of the colon are typically performed on colonography, one for the first time in the supine position and one time in the prone position. In one embodiment of the method according to the invention, the two recordings are reconstructed separately from one another and in each case processed according to the method described here. Then, a registration R of the two processed reconstructions is performed to check the consistency of the 3D reconstructions themselves and the information obtained from them. There may also be a visual output VA of the two registered 3D reconstructions, whereby deviations become visually detectable. Alternatively, only a registration R of two 3D reconstructions can be done to a common, registered 3D reconstruction of the hollow organ 1 to create. Then, this joint 3D reconstruction can be subjected to the individual steps (such as the first determination B1, the selection A, etc.) of the method according to the invention. Furthermore, the two 3D reconstruction can be based on images using different imaging modalities, such as CT and MRI. This makes it possible to combine complementary information, which in turn results in the detection of tumors 5 is simplified as more information is available about tumors 5 to identify. In particular, in one embodiment of the method according to the invention, the second 3D reconstruction is based on a recording by means of PET. Because PET allows the use of radioactive contrast agents, also known as tracers, a very specific imaging of tumors 5 , The combination of a high-resolution imaging modality such as CT or MRI with a very specific imaging modality such as PET allows both a tumor 5 safely and accurately identify and more precisely localize it and characterize it by its geometric properties. Thus, the inventive method also facilitates a more extensive diagnosis.

The diagnosis by a treating physician is also supported by an automatic assessment Bu in the context of the method according to the invention. At least one particular property of the selected area is judged as to whether the selected area is a tumor 5 is. The particular properties may be geometric properties that occur during the first and possibly second determination B2, as well as the determination of further properties such as the signal intensity of the selected region. In other words, the aforementioned classification is extended by the dimensions of the respective particular characteristics, and the result of the classification is output as judgment Bu. Such a procedure is also known as "Computer Aided Diagnosis" (CAD) and facilitates the final diagnosis of the attending physician. In one embodiment of the method according to the invention, the judgment Bu also depends on the initially selected recording mode, which is taken into account in the classification. The judgment Bu is finally presented in the form of a visual output VA.

2 shows a schematic representation of the course 4 the cross sections of a hollow organ 1 the example of the colon according to the method of the invention. The central line 2 of the reconstructed hollow organ 1 is along the natural longitudinal axis of the hollow organ 1 oriented. The history 4 the cross sections of the hollow organ 1 along the central line 2 shows in the left, healthy part in 2 The progress 4 the intestinal folds. The cross sections are in the in 2 all shown along an axis in parallel cross-sectional areas 3 has been determined. The cross-sectional area 3 is perpendicular to the center line 2 oriented and sticks in 2 out of the drawing plane or into it. The line in 2 the cross-sectional area 3 represents, thus also shows the axis along which the course 4 is determined. The history 4 the cross sections points to the right part in 2 an area on top of a tumor 5 close as it deviates from the regular pattern of intestinal folds. The selected area is marked by a different color scheme and thus easily recognizable in the visual output VA. In a "flight" through the intestine, the tumor is 5 as a constriction of the internal cavity of the intestine.

3 shows a block diagram of the system according to the invention, which is designed for carrying out the method according to the invention. The system comprises an image processing unit BvE, designed for the 3D reconstruction of a hollow organ 1 and for providing at least one central line 2 of the hollow organ 1 in the 3D reconstruction. Such an image processing unit BvE can comprise further subunits, for example a reconstruction unit which reconstructs a 3D data volume from the individual projections of a tomographic image. Furthermore, the image processing unit BvE may comprise a rendering unit which segments and renders the reconstructed data volume such that a 3D reconstruction of the hollow organ 1 as well as the associated center line 2 to be provided. The image processing unit BvE and its subunits can be designed in the form of both hardware and software. For example, the image processing unit BvE or one of its subunits is designed as a so-called FPGA (acronym for the field programmable gate array) or comprises an arithmetic logic unit.

Furthermore, the system comprises a determination unit BE, designed for a first determination B1 of a course 4 of cross sections of a hollow organ 1 along a central line 2 based on a 3D reconstruction of the hollow organ 1 and based on the provision of at least one centerline 2 of the hollow organ 1 in the 3D reconstruction. Furthermore, the determination unit BE is designed for a second determination B2 of at least one property of the selected area, the property for detecting a tumor 5 suitable is. The determination unit BE is typically in the form of software.

Furthermore, the system comprises a selection unit AE, designed to select A of a region of the hollow organ 1 by means of the course 4 the cross-sections, wherein the region at least one geometric property of a tumor 5 having. Since the selection A requires methods of pattern recognition, the selection unit AE in one embodiment of the invention also includes a database on the gradients 4 or properties of the gradients 4 are saved with the history 4 or the properties of the gradient 4 the cross sections of the reconstructed hollow organ 1 be compared. The database includes stored on a physical memory, retrievable stored data.

Furthermore, the system comprises a registration unit RE designed to register R at least one area of the 3D reconstruction with a second 3D reconstruction of at least one area of the hollow organ 1 , The registration unit RE, similar to the image processing unit BvE, can be designed both as hardware and as software. Further, the system comprises a judgment unit BuE adapted to judge Bu of the at least one specific property of the selected area as to whether the selected area is a tumor 5 is. Similar to the selection unit AE, the assessment unit BuE may include a database on which retrievably stored data is stored.

If one of the units mentioned here is in the form of software, then the software is configured to use a computer 12 certain, the respective unit associated process steps can perform. The computer 12 It must in each case have the prerequisites such as a corresponding main memory, a corresponding graphics card or a corresponding logic unit, so that the respective method steps can be carried out efficiently. Furthermore, the computer can 12 itself also be part of the respective unit.

4 shows an extended system according to the invention. The imaging device 6 , here in the form of a CT device, has a recording unit comprising a radiation emitter 8th and comprising a radiation detector 9 , At the radiation emitter 8th a CT device is typically an X-ray tube. At the radiation detector 9 A CT device is typically a line or flat detector, but it may also be a scintillator counter or CCD camera. When taking a picture, the patient lies 3 on a patient couch 13 that way with a lying base 14 connected is that he is the patient bed 13 with the patient 3 wearing. The patient bed 13 is designed for the patient 3 along a take-up direction through the opening 10 to move the recording unit.

It can affect the imaging device 6 for example, to act an MRI device. In an MRI apparatus, the receiving unit is designed in the form of at least one RF coil. A single RF coil can serve both as a radiation emitter 8th as well as a radiation detector 9 be educated. In particular, the RF coil may be a local coil.

The pictures of the imaging device 6 are for processing and / or presentation to a computer 12 Posted. In the embodiment shown here, the computer has 12 both an image processing unit BvE and a determination unit BE. In the embodiment shown here, the image processing unit BvE comprises the registration unit RE, and the determination unit BE comprises the selection unit AE and the assessment unit BuE.

The image processing unit BvE and the determination unit BE can be embodied in the form of both hardware and software. Both the image processing unit BvE and the determination unit BE can be implemented on different devices. For example, the image processing unit BvE comprises a reconstruction unit that forms part of the imaging device 6 is formed while another unit of the image processing unit BvE, for example, a rendering unit, is formed as part of a server.

The computer 12 is with an output unit 11 and an input unit 7 connected. At the output unit 11 For example, it is one (or more) LCD, plasma, or OLED screen (s). The output on the output unit 11 includes, for example, a graphical user interface for manually entering patient data and a recording mode and also serves the visual output VA of the 3D reconstruction of the hollow organ 1 as well as all information obtained during the process according to the invention. At the input unit 7 For example, it is a keyboard, a mouse, a so-called touch screen or even a microphone for voice input.

While the invention has been further illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples, and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention. In particular, method steps can be carried out in a sequence other than that indicated.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• DE 102004027709 B4 [0003, 0035]

Claims (18)

Method for the automatic detection of a tumor ( 5 ), based on a 3D reconstruction of a hollow organ ( 1 ) and based on the provision of at least one central line ( 2 ) of the hollow organ ( 1 ) in the 3D reconstruction, comprising the following steps: - first determination (B1) of a course ( 4 ) of cross sections of the hollow organ ( 1 ) along the central line ( 2 ), - selection (A) of a region of the hollow organ ( 1 ) by means of the course ( 4 ) of the cross-sections, the region having at least one geometric property of a tumor ( 5 ) having. Method according to claim 1, wherein the first determination (B1) of the course ( 4 ) of cross-sections by means of substantially perpendicular to the central line ( 2 ) oriented cross-sectional areas ( 3 ) of the hollow organ ( 1 ) he follows. The method of claim 1 or 2, further comprising: second determination (B2) of at least one property of the selected region, wherein the property for detecting a tumor ( 5 ) suitable is. Method according to one of claims 1 to 3, wherein the second determination (B2) comprises the determination of the signal strength of the selected area. Method according to one of claims 1 to 4, wherein the second determination (B2) comprises the determination of at least one geometric property of the selected area. Method according to one of claims 1 to 5, further comprising: - registration (R) of at least part of the 3D reconstruction with a second 3D reconstruction of at least a part of the hollow organ ( 1 ). The method of claim 6, wherein the two 3D reconstructions each based on recordings by means of different imaging modalities. The method of claim 7, wherein the second 3D reconstruction is based on a photograph by positron emission tomography. The method of claim 6 or 7, wherein further based on the second 3D reconstruction, a method according to any one of claims 1 to 5 is performed. The method of any one of claims 1 to 9, further comprising: - assessing (Bu) the at least one particular property of the selected region as to whether the selected region is a tumor ( 5 ). Method according to one of claims 1 to 10, further comprising: - visual output (VA) of the reconstructed hollow organ ( 1 ) and at least part of the information obtained in each step of the process. System for automatic detection of a tumor ( 5 ), comprising the following units: a determination unit (BE) designed for a first determination (B1) of a course ( 4 ) of cross sections of a hollow organ ( 1 ) along a central line ( 2 ), based on a 3D reconstruction of the hollow organ ( 1 ) and based on the provision of at least one central line ( 2 ) of the hollow organ ( 1 ) in the 3D reconstruction, - a selection unit (AE), designed to select (A) a region of the hollow organ ( 1 ) by means of the course ( 4 ) of the cross-sections, the region having at least one geometric property of a tumor ( 5 ) having. The system of claim 12, wherein the determining unit (BE) is adapted to a second determination (B2) of at least one property of the selected area, wherein the property for detecting a tumor ( 5 ) suitable is. A system according to claim 12 or 13, comprising: - a registration unit (RE) adapted to register (R) at least one region of the 3D reconstruction with a second 3D reconstruction of at least a region of the hollow organ ( 1 ). A system according to any one of claims 12 to 14, comprising: - an output unit ( 11 ) designed for visual output (VA) of the reconstructed hollow organ ( 1 ) and at least part of the information obtained in each step of the process. A system according to any one of claims 12 to 15, comprising: - a judging unit (BuE) adapted to judge (Bu) the at least one specific property of the selected area as to whether the selected area is a tumor (Bu); 5 ). System according to one of claims 12 to 16, comprising an image processing unit (BvE), designed for the 3D reconstruction of a hollow organ ( 1 ) and to provide at least one central line ( 2 ) of the hollow organ ( 1 ) in the 3D reconstruction. System according to one of claims 12 to 17, comprising an imaging device ( 6 ) designed to acquire tomographic data of a hollow organ ( 1 ).

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