Next Patent: Temporal image comparison method
Next Patent: Temporal image comparison method
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[0001] 1. Field of the Invention
[0002] The invention is directed to a method, a device and a software product for the medical image processing of datasets of a three-dimensional character acquired from medical examination procedures, of the type wherein a separation of the data of relevant anatomical structures as well as of other structures is undertaken proceeding from data in the form of volume element, and a spatial presentation of at least one structure of interest ensues.
[0003] 2. Description of the Prior Art
[0004] The human ability to conceptualize quickly reaches it limits in the spatial interpretation of the information from X-ray exposures or from tomograms as acquired with modern tomographic methods. Modern methods of medical image processing therefore convert the information of a three-dimensional character acquired in medical examinations into spatial impressions of the inside of the body. In general, however, it is not adequate to merely convey a spatial impression of the displayed body region to the medical practitioner. For preparing a reliable diagnosis or for planning a therapeutic measure or a surgical intervention, however, the medical practitioner needs a reduction of the displayed data to what is essential to the practitioner. In other words, the subject of the practitioner's interest must clearly contrast with the environment having only secondary informational content. A number of methods were developed for this purpose that enable an allocation of individual measure values to relevant anatomical structures such as, for example, nerves or fat tissue, bones or tissue equivalent to muscle, as well as to non-anatomical structures such as, for example, foreign bodies. These methods are referred to as segmenting and form the pre-condition allowing a medical practitioner to view, for example, the bone structure of a patient at the picture screen isolated from other tissues.
[0005] For planning a surgical intervention, for example after an accident resulting in a complicated fracture, however, this form of presentation of the examination results is often inadequate since although it reflects the actual condition of the structure of interest it does not allow a manipulation of the data with respect to measures to be undertaken; the individual subjects within each and every structure remain fixed in their geometrical arrangement relative to one another in known segmenting methods. The preparation for an intervention to treat a complex multiple fracture therefore requires an enormous mental effort on the part of the orthopedist since he or she cannot verify the allocation of the various fracture surfaces and thus bone fragments to one another at the picture screen. “Fast Visualization, Manipulation, and Analysis of Binary Volumetric Objects”, IEEE Computer Graphics and Applications, November 1991, pages 53-62, proposes a method for splitting an anatomical structure into two components along a plane to be arbitrarily defined. The separated components can be repositioned in space independently of the original structure.
[0006] In “Simulating Motion of Anatomical Objects with Volume-Based 3D-Visualization”, R. A.Robb (Editor): Visualization in Biomedical Computing, Proc. SPIE 2359, 1994, pages 291-300, B. Plesser, U. Thiede and K. H. Hohne propose the division of an anatomical subject into partial subjects that can be subsequently converted into a new spatial arrangement.
[0007] It is an object of the present invention to provide a method and an apparatus for separating an anatomical structure into its individual subjects, so that these can be arbitrarily re-arranged independently from one another in the spatial presentation either individually and/or in groups.
[0008] This object is achieved in a method, an apparatus and a software product for imaging processing of datasets with a three-dimensional character that are obtained from medical examination procedures, wherein a separation of the data of relevant anatomical structure as well as other structures is undertaken proceeding from data in the form of volume elements and a spatial presentation of at least one structure of interest is undertaken, and wherein at least one of the individual subjects of the structure of interest is separated such that the individual subject can be re-positioned in the spatial presentation. A segmenting or separation of the individual subjects from one another ensues by dividing the overall volume of the anatomical structure into partial volumes in a first step, with an individual subject being completely contained in the partial volume allocated to it. All other data not to be considered as belonging to this individual subject are removed from this partial volume in a second step. The resultant data of each partial volume processed in this way are stored in a third step.
[0009] Time-consuming procedures thus can be shifted from the operation into the planning phase. The precise planning of an intervention in the preparatory phase of the operation not only shortens the duration of the intervention and, thus, produces less stress on the patient, but also enables more precise and safer work for the medical practitioner during the operation. Also advantageously, the use of suitable aids such as, for example, screws, nails, etc., can already be tested before the operation. Likewise advantageously, implants can now be pre-shaped according to the identifiable conditions on the basis of the present invention and no longer need be intuitively designed during the course of the operation.
[0010] In an embodiment of the invention, the partial volumes have the shape of a cuboid, as a result of which the individual volumes can be easily joined. Together with the data of each partial volume, the appertaining coordinate information are also stored. The editing of 3D computer tomography datasets is particularly advantageous, so the selection of a bone structure as a structure of interest, with the individual bones and/or bone fragments as individual subjects of the structure to be segmented, is especially advantageous.
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[0017] A bone fracture with a dislocated fragment of the os metacarpal V can be clearly recognized in the left half of
[0018] An assessment as to whether the two fracture surfaces can be seamlessly joined to one another assumes that the two fragments of the broken bone can be aligned and positioned independently of one another. After segmentation of the dataset into anatomical structures, however, the illustrated bone structure is obtained as an interconnected subject. The subdivision into the discrete subjects of the structure that is unconsciously performed by the viewer, into bones and bone fragments in the present example, is not reduplicated by the conventionally available segmenting methods.
[0019] In order to achieve a further segmenting of the structures within an anatomical structure, the existing 3D CT dataset is first resolved into separate volumes according to method step S
[0020] Many individual subjects are in immediate proximity to one another, for which reason component parts of neighboring subjects are also generally contained in the individual partial volumes in addition to the desired individual subject. In the next step S
[0021] This advanced segmenting is implemented for all bones or, respectively, bone fragments of the 3D CT dataset S
[0022] However, the fixed geometrical reference of the discrete subjects relative to one another has been eliminated at this point in the method.
[0023] As can be seen in the result thereof, for example in
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[0025] Although modifications and changes may be suggested by those skilled in the art, it is the invention of the inventor to embody within the patent warranted heron all changes and modifications as reasonably and properly come within the scope of his contribution to the art.