Patent Application
20080027908
The present application hereby claims priority under 35 U.S.C. §119 on German patent application number DE 10 2006 034 185.6 filed Jul. 24, 2006, the entire contents of which is hereby incorporated herein by reference.
Embodiments of the invention generally relate to a method for requesting metadata which is contained in a data stream, or cumulation data which is derived from the metadata. They further generally relate to a device for processing a data stream, in particular a DICOM data stream.
DICOM (Digital Imaging and Communications in Medicine) is an open standard which was developed and is maintained by the American College of Radiology (ACR) and the National Electrical Manufacturers Association (NEMA) for the exchange of medical image data and which, in particular, provides and specifies communication protocols for network-wide communication between at least one imaging device and associated processing and storage entities, file formats for various storage media, and uniform data structures for the actual image data and meta-information assigned thereto, e.g. patient data, device parameters or recording parameters. Above all, DICOM is intended to ensure the interoperability between various medical applications; within this concept, the medical imaging devices communicate independently of the system platform in use, the operating system or the manufacturer.
For this reason, the DICOM standard does not include any hardware-specific implementation rules or specifications in respect of the underlying database or storage structure. In particular, the associated access algorithms or access techniques and the details of the processing routines are not defined or standardized in greater detail.
The payload information and meta-information contained in a DICOM hierarchy are usually bundled in a continuous data stream, transferred within the network, (temporarily) stored, and processed sequentially in an associated data processing entity. In this case, in a hospital or community medical practice, for example, there is usually a certain amount of metadata (e.g. patient data) which, in comparison with the other parts of the data stream (e.g. the actual image data), must be accessed relatively frequently and might also be modified comparatively frequently.
In particular, it is necessary repeatedly to access processing attributes or status attributes (so-called flags) assigned to the individual information units of the DICOM hierarchy which are present in the data stream, and to request the current value of said attributes. This might involve, for example, the standardized DICOM flags “completion” (0040,A491) or “verification” (0040,A493), wherein the hexadecimal-encoded identification sequences preceding the relevant value field are specified in parentheses and the flags in the data stream can be identified and/or located with reference to said identification sequences. In some cases, it is also necessary frequently to query and read out or (temporarily) modify processing attributes such as, for example, “archived” or “exported” or other data fields which have freely definable contents and are provided in the context of proprietary extensions to the DICOM standard. These queries are distinctly time-consuming due to the sequential access to the DICOM data stream, particularly if they occur repeatedly, since it is necessary to analyze anew the whole data stream or at least a large portion thereof (e.g. up to a defined interrupt criterion) in a parser in the case of each individual query.
In this case, frequently it is not individual metadata or attributes themselves that are of interest, but merely data which is formed or derived therefrom and is modified, combined or cumulated, said data being referred to below as cumulation data for short. In the DICOM context featuring a “patient-study-series-instance” information hierarchy, for example, frequently all that is of interest is whether all instances of a series are already archived. However, since such combined information is frequently not present in the DICOM data stream itself, nor can it easily be added thereto, all that remains according to the current prior art is, with regard to each query, to check the data stream again in a parser for the presence of the corresponding individual flags and to generate the desired cumulated information therefrom. These search and query operations require a huge amount of (computing) time, particularly in the case of a study including several thousands of images, and therefore protracted and undesirable delays for the user and the operator of the corresponding medical system can only be avoided - if at all - by using comparatively powerful and therefore expensive hardware components.
In at least one embodiment, the present invention therefore addresses the problem of specifying a method of the type cited in the introduction and/or an associated device for executing the method, the method and/or device of at least one embodiment allowing a particularly efficient and time-saving request of metadata contained in a data stream, in particular of a frequently required subset of this metadata.
With reference to the method, the problem may be improved upon or even solved in accordance with at least one embodiment of the invention by extracting at least a part of the metadata from the incoming data stream and copying it into a metadata storage during a preparation phase, and by storing the data stream in a data stream storage, wherein in a request phase which chronologically succeeds the preparation phase, incoming queries from an assigned application or from a system service for specific metadata or cumulation data are answered as far as possible on the basis of the metadata which is stored in the metadata storage, or on the basis of cumulation data which is derived therefrom, and wherein otherwise the data stream which is stored in the data stream storage is used for answering the request.
At least one embodiment of the invention has as its starting point the consideration that, in order to improve the performance of the method, analyzing the complete data stream with the aid of a parser for each individual request for metadata (more precisely: the current value of a metadata field) should be avoided. Instead, the data stream should be subjected to a pre-analysis once in a preparation phase, wherein according to at least one embodiment of the invention in one stage the most frequently queried metadata or the values of corresponding data fields are “collected”, extracted from the data stream and stored in a manner which allows the extracted metadata to be identified unambiguously and, according to its respective meaning, to be assigned to the original position in the data stream or the location in the underlying information hierarchy of the data stream.
The metadata storage therefore represents a “pool” of frequently queried metadata, which is available there and separated from the less frequently demanded metadata and/or the “payload data”, this being very extensive in terms of data volume in some cases, and which is therefore easily accessible without time-intensive searching in the request phase following completion of the preparation phase. Furthermore, in this way it is possible to alter or modify the extracted metadata e.g. in the metadata storage without having to alter the original complete data stream. Furthermore, cumulated or combined data can be formed as required from the extracted metadata in a particularly efficient manner. As long as the metadata that is required to answer the respective query is present in the metadata storage, or the desired cumulation data can be formed exclusively from the extracted metadata, recourse to the complete data stream which is stored in a data stream storage is not necessary. If required, however, the complete data stream is also available.
The extraction of the metadata preferably takes place in a data extraction unit, which can also be a software-based component of a general data processing system. In this case, the metadata that is to be extracted from the data stream can be configured e.g. in a metadata list which can advantageously be adapted to changing query customs or frequencies. Although it is conceivable that the extraction acts in the manner of a shift operation, in which the extracted metadata is deleted from the input data stream, it is nonetheless advantageous always to copy the relevant metadata into the metadata storage. In this case, the output data stream which leaves the data extraction unit and is supplied to the data stream storage is identical to the input data stream and, if required, still contains all of its originally available--information in unmodified form and sequence.
The application of the method proposed here is particularly advantageous in the case of a data stream which—like e.g. a DICOM data stream - represents information which is hierarchically arranged in a tree structure, wherein a record of individual meta-information is assigned in each case to information units which form at least some nodes and end-nodes. For example, the DICOM information hierarchy “patient-study-series-instance” cited in the introduction can be used as a basis, wherein the information unit “patient” is usually optional, i.e. is not mandatory. The information units which are present on the logical/conceptual level and the meta-information which is assigned or attached thereto are represented on the implementation level of the data stream by corresponding data units or metadata which are advantageously identifiable by way of the individual identification sequences or UIDs (Unique Identifiers) which precede actual data value fields. However, it is also possible for metadata which does not have a direct correspondence on the logical level of the tree diagram to be integrated into the data stream.
The metadata to be extracted may include, for example, status attributes or processing attributes or “flags” of the type mentioned in the introduction, e.g. “archive” flags or similar, whose value is queried particularly frequently according to at least one embodiment of the invention. The metadata which is extracted from the data stream is advantageously stored in the metadata storage in such a way that its assignment to the information units that are organized in the tree structure, in particular to the attached meta-information, is retained. In a realization which is kept particularly simple, the extracted data values together with their identification sequences are strung together in a new and comparatively short (meta) data stream and stored thus in the metadata storage such that, in the case of a corresponding query from an application or a system service, only the short metadata stream from the metadata storage and not the original complete data stream must be parsed. In a variant which is somewhat costlier to implement but is nonetheless particularly advantageous in respect of the request effectiveness, the extracted metadata is stored in a data structure having direct, non-sequential access (e.g. array, relational database, etc.), wherein this data structure advantageously emulates to a large extent the information hierarchy (e.g. tree structure with nodes and end-nodes) that underlies the data stream.
In an advantageous development of at least one embodiment, during the preparation phase, cumulation data is formed from the metadata which is copied into the metadata storage, and is stored in a cumulation data storage, wherein incoming queries from an assigned application or from a system service during the subsequent request phase for specific metadata or cumulation data are answered on the basis of the cumulation data which is stored in the cumulation data storage if available there, alternatively on the basis of the metadata which is stored in the metadata storage and, if not available there either, on the basis of the data stream which is stored in the data stream storage. In practice, the (raw) metadata storage and the cumulation data storage and possibly the data stream storage can be separate storage areas of the same physical storage.
The described approach is particularly suitable if such cumulation data rather than the original (raw) metadata is the actual subject matter of the interest of the query, but the cumulation data itself is not explicitly present in the data stream, e.g. in the case of the question whether the “archive” flag is set for all elements of a series or a study. Precisely if such queries occur more frequently and repeatedly, the. performance advantages of the advance calculation of the cumulation data, this being aimed to some extent at a “stockpiling”, clearly outweigh the disadvantages associated with the additional storage requirements for the temporary storage of the cumulation data. Moreover, the querying application is relieved or freed from the task of itself having to form the cumulation data from the raw metadata, such that the program code of the application can be kept particularly simple, in particular with respect to the request algorithm. In particular, request interfaces which are integrated in the relevant application do not have to take the structure and the format of the (raw) metadata into consideration in this case.
In a particularly simple variant, queries from an application or system service are initially directed or forwarded to the cumulation data storage. If the query can be answered on the basis of the data available there, the answer is output and passed or transferred to the application. The query is thus successfully answered and concluded. Otherwise, the query is directed to the metadata storage in a next stage. If the query is again unsuccessful, i.e. cannot be answered on the basis of the extracted metadata, the complete data stream is still available in the data stream storage in a final stage of query processing.
In an advantageous development, queries from an application or system service are however analyzed on the basis of a decision algorithm which accesses an assignment table, and forwarded to the cumulation- data storage, the metadata storage or the data stream storage depending on the availability of the data required for answering. For the purposes of at least one embodiment of the invention, this decision and forwarding algorithm is integrated into a metadata information service which is connected on the data flow side between the querying application and the relevant storage units (metadata storage, cumulation data storage and data stream storage). The assignment table advantageously contains all information required for forwarding queries as applicable, said information relating to the information hierarchy (e.g. the DICOM hierarchy) underlying the data stream and to the available metadata—depending on the hierarchy level—and its permissible values, to the extracted metadata which is available in the metadata storage and, if applicable, to the type and manner of its cumulation and the format and structure of its storage in the respective storage. In this way, for example, an unnecessary forwarding of the queries to the cumulation data storage can be prevented if the data that is required for answering the query is not even present there; the query can applicably be directed immediately to the metadata storage or possibly also to the data stream storage instead.
Furthermore, it is particularly advantageous if composite queries from an application or a system service are translated by the aforementioned metadata information service into individual queries which, depending on availability, are answered on the basis of the data in the cumulation data storage, in the metadata storage or in the data stream storage, wherein the individual answers that are received are composed by the metadata information service into an overall answer which is forwarded to the querying application or to the system service. This preferably takes place in a manner which is transparent to the application.
A cache mechanism is advantageously integrated in the system architecture for carrying out the method. For the purposes of at least one embodiment of the invention, the cache mechanism is part of the metadata information service. In this case, incoming queries from an application or a system service and answers that are received in response are temporarily stored in a query storage (cache), wherein new queries are initially forwarded to the query storage and, if possible, answered on the basis of the data which is temporarily stored there. This allows recurring and very similar queries to be answered particularly quickly without having to access the other storage entities, which usually have longer access times.
It is also possible here again to break complex composite queries into individual queries which can be forwarded either directly to the cache storage or to the other storages (metadata storage, cumulation data storage, data stream storage) according to the availability of the data. For the purposes of at least one embodiment of the invention, the periodic or needs-based refreshment of the cache contents, whereby query results that are now outdated are replaced by current results, is monitored and executed by a suitable refresh algorithm.
It should also be noted that the previously described concepts and principles for the metadata information service (transparent transformation and relevant forwarding of complex queries, cache mechanism, etc.) can obviously also be used—slightly adapted—if the (raw) metadata storage is ignored in a specific case and the metadata is prepared and processed to form cumulation data immediately upon extraction from the data stream. Alternatively, it is also possible for solely a (raw) metadata storage but no cumulation data storage to exist.
In a particularly advantageous configuration, cumulation data or cumulated attributes are formed from the metadata which is stored in the metadata storage and is organized according to a tree structure, particularly from such metadata as that which represents processing attributes or status attributes, by forming a combination value from a number of metadata elements belonging to the same hierarchy level of the tree structure, said combination value being assigned to a data field corresponding to the next higher hierarchy level.
Whether the “printed” attribute or the “archived” attribute is set in all “instances” of a “series”, for example, might be of interest to a querying application in the context of DICOM. Such a combinational characteristic or attribute, containing the desired information in condensed form, is however not provided on either the “instance” or “series” hierarchy level in the DICOM standard. This shortcoming is resolved according to the concept now proposed, in that corresponding cumulated or compound attributes are produced and taken into consideration when forming the cumulation data.
For the purposes of at least one embodiment of the invention, the combined attributes are assigned to the next higher hierarchy level as a single “general attribute” in this case. In the cited example, an attribute, e.g. “printed”, which is set on the “series” level would therefore signify that the corresponding attribute is set or should be considered to be set for all units of the “instance” level located immediately below the “series” level. By virtue of the cumulation data which is formed thus, the cumulation data storage holds the relevant information directly available for the querying application; it is not necessary to parse the whole data stream anew each time and compose the desired overall result from the individual results that are derived therefrom.
In addition to the rules outlined above by way of example for forming and interpreting cumulation data, in particular cumulated or aggregated attributes, it is also possible to establish further semantic conventions which are aimed at minimizing the number of required accesses to the various storage entities and the number of required processing steps when handling the respective query or when actively altering attributes. Generally speaking, in this case the value of data fields corresponding to nodes and end-nodes of a hierarchy level of the tree structure is advantageously determined implicitly according to semantics which depend on the ancestors, the descendants or the siblings.
In the case of a first variant which is also known as “implicit children”, an attribute or flag which is set for a node on a specific level of the tree hierarchy has the implicit significance that the corresponding attribute or flag should also be considered to be set for all descendants (children) of the node concerned. For the purposes of at least one embodiment of the invention, this applies not only to the immediate offspring, but also to the generations of grandchildren, great-grandchildren, etc. as far as the end-nodes of the tree. In a second variant which is also known as “implicit parents”, an attribute which is set for a node or an end-node of the tree applies equally to all ancestors (parents). For the purposes of at least one embodiment of the invention, this again applies to ancestors or predecessor nodes of each level as far as the root of the tree. Finally, there is also the variant which is known as “implicit siblings”, in which an attribute which is set for a node or an end-node applies equally to all siblings belonging to the same parent node. In an advanced variant, it is also possible for all nodes or end-nodes of the relevant hierarchy level (generation) to be covered by the implicit significance of the attribute which is set.
From a practical standpoint, an optimization according to the “implicit children” method is particularly preferred, since it allows a particularly clear view of the data structure under all conceivable circumstances and, avoiding any ambiguities, is particularly easy and intuitive to understand and ultimately to implement. In this case, an XML-based solution at the present time appears to be particularly suitable for a practical realization and implementation of the concept, in particular for modeling the tree hierarchy, wherein query languages such as XPath or XQuery can be used for requesting and altering the data. Alternatively, for example, a relational database system can be used in connection with the query language SQL.
The cited semantic conventions, and any proprietary data fields and the like which are not DICOM-compliant, are preferably used exclusively for the cumulation data which is held or filed in the cumulation data storage, while the (raw) metadata storage stores exclusively DICOM-compliant metadata or attributes having explicit significance, i.e. no implicit semantics. As a result, metadata having the full original information content (e.g. time stamp) is available in the (raw) metadata storage—provided it has been extracted from the data stream—in case of doubt or if required.
Temporary alterations of the metadata or cumulation data, these being initiated by an assigned application, a system service or the metadata information service, are preferably performed subject to the agreed semantics on the cumulation data which is stored in the cumulation data storage. Thus, the data stream and the metadata in the metadata storage which is extracted therefrom remain as far as possible untouched. For the purposes of the invention, the previously cited metadata information service is responsible for the execution of such alterations and requests.
With regard to at least one embodiment of the device, the problem cited in the introduction may be improved upon or even solved by way of a device for processing a data stream, in particular a DICOM data stream, said device featuring a data extraction unit for extracting metadata which is contained in the data stream, a metadata storage for storing the extracted metadata, and a data stream storage for storing the complete data stream, wherein an application which is linked to the device accesses specific metadata, or cumulation data which is derived from the metadata, via an interconnected metadata information service that is connected on the data side to the metadata storage and to the data stream storage.
In an advantageous development, at least one embodiment of the device additionally features a data cumulation unit, this being interconnected on the data side between the metadata storage and the metadata information service, for forming cumulation data which is derived from the extracted metadata, and a cumulation data storage for storing the cumulation data. For the purposes of at least one embodiment of the invention, when forming the cumulation data, the data cumulation unit takes into consideration previously agreed implicit semantics as per the description above.
The advantages achieved by at least one embodiment of the invention reside particularly in providing a concept which, with acceptable complexity of the system architecture, allows a particularly rapid and efficient request and/or alteration of metadata which is contained in a data stream, particularly in a DICOM data stream, and in particular of status attributes or processing attributes. This objective is achieved by extracting the frequently required metadata from the data stream in a preliminary step and storing it “collected” in an independent separate storage entity for a multiplicity of subsequent requests. By virtue of the reduction, resulting from the data extraction, in the volume of data which must subsequently be searched, the burden of each subsequent request decreases correspondingly.
The concept can be further optimized by way of a suitable representation of the extracted metadata in a data structure which is adapted to the requests. It is moreover possible to generate supplementary information, which is not present in the data stream itself but is useful and frequently required, from the standard metadata in a single pass during the preparation phase, and to make it available for subsequent retrieval without the need to modify the data stream for this purpose. As a result of the choice of suitable compression and presentation methods, e.g. by establishing implicit semantics, the request and alteration of such cumulation data can be further optimized, e.g. by reducing the number of attributes that must be processed per alteration operation. The request method appears completely transparent from the perspective of the querying application, and therefore the integration measures relating to this transpire to be particularly simple.
The described aggregation and processing techniques are not just applicable to metadata or flags extracted from the data stream, but also to additionally defined non-standardized processing information which is not stored in the data stream itself, e.g. flags of the type “printed”, “archived” or “marked”. By way of a concrete application example for a flag of the type “marked”, it is possible to imagine that, for example, in an application consisting of a plurality of application tasks, one of the tasks sets the corresponding flag on a set of DICOM streams which are read and analyzed by another application task that executes work stages using the marked images accordingly.
A further preferred application field for the concepts and techniques described here is in the domain of workflow processing and control (workflow management), e.g. in the creation of so-called Performed Procedure Steps (PPS), in particular in relation to the monitoring, processing and management of workflows that occur in a hospital with the aid of a hospital information system (KIS). A PPS typically contains the identification sequences (UIDs) of all DICOM instances that are handled in a processing step or workflow step and, after it is generated, said PPS is sent to the other information systems that are required for the handling of the complete workflow, it therefore being possible for these other information systems easily to see which steps have already been serviced. As a result of (temporarily) marking, at the level of the metadata storage or the cumulation data storage, instances, series or studies which are handled or changed in the context of the workflow, the generation of a PPS is supported without constantly having to request or modify the DICOM data stream itself for this purpose. Consequently, the new concept could also be referred to using a keyword such as “virtual PPS”.
An example embodiment of the invention is explained in greater detail with reference to the drawings, in which:
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present invention-. As used herein, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “includes” and/or “including”, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or- components-, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper”, and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, term such as “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein are interpreted accordingly.
Although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, it should be understood that these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or section from another region, layer, or section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of the present invention.
In describing example embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this patent specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner.
Referencing the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, example embodiments of the present patent application are hereafter described. Like numbers refer to like elements throughout. As used herein, the terms “and/or” and “at least one of” include any and all combinations of one or more of the associated listed items.
In schematic and simplified form,
It is also evident from
A data stream 16 illustrated in
The ID of an attribute is generally composed of a so-called group number and an attribute number, both of which are usually four-character hexadecimal numbers. For example, the standardized DICOM attribute “completion” has the ID (0040,A491). Directly appended to the identification sequence 20 or ID in the data stream 16 is a data field 22 which represents the value of the attribute, e.g. “1” for “set” or “0” for “not set”. The sequence of the attributes in the data stream 16 is not permanently preset; the attributes contained in the data stream 16 are usually organized according to group number or attribute number, but not according to information unit 10 (patient, study, series, instance). In order to read out the value of a specific attribute from the data stream 16, it is therefore normally necessary to supply the whole DICOM data stream 16 to a parser which sequentially reads out the individual bits of the data stream 16 until the desired ID and thus the sought attribute is reached. The operation starts from the beginning again for the next query, this being a decidedly time-consuming and inefficient approach, particularly in the case of recurring queries of the same type.
In order to improve the request efficiency, the processing device 24 which is schematically illustrated with its underlying logical functional components in the data flowchart in
Using the communication path 33, the data extraction unit 26 informs a data cumulation unit 36, which is connected to the metadata storage 28 on the data side, of newly arrived metadata in the metadata storage 28, whereupon the data cumulation unit 36 queries selected metadata from the metadata storage 28 via the query channel 34 and, according to its predefined rules, modifies and/or processes the metadata which is then received via the query channel 35 to form combined cumulation data. The cumulation data which is generated thus is then transferred via the data channel 37 to a further storage entity, the cumulation data storage 38, and stored there for answering future queries.
In the flow diagram illustrated in
External user software or application 40 is linked, on one hand, via the interconnected metadata information service 42 to the above-described storage architecture comprising metadata storage 28, cumulation data storage 38 and data stream storage 32 on the data side; on the other hand, if necessary it has direct access via the query channel 44 and the DICOM data channel 46 to the complete data stream which is stored in the data stream storage 32. The direct communication path between the application 40 and the data stream storage 32 is normally only used for the transfer of large volumes of data, e.g. 2D or 3D image data; queries relating to metadata contained in the data stream, in particular to the value of status attributes or processing attributes or to cumulation data derived therefrom, are however sent from the application 40 via the query channel 41 to the metadata information service 42. The query arriving there is analyzed by the metadata information service 42 and, depending on the availability of the data required to answer it, is preferably forwarded via the query channel 48 to the cumulation data storage 38, alternatively via the query channel 50 to the metadata storage 28, and otherwise via the query channel 52 to the data stream storage 32. Complex composite queries are divided into individual queries if necessary and distributed to the corresponding storage entities.
The received answer to the query, i.e. the desired (raw or aggregated) metadata is then transferred via the data channel 54, the data channel 56 or the data channel 58 to the metadata information service 42. If a (complex) query was previously divided across the various storage entities, the individual answers are reassembled or composed again by the metadata information service 42. Finally, the (complete) answer is transferred from the metadata information service 42 via the data channel 59 to the querying application 40.
In the flow diagram illustrated in
In
In
The application of such implicit semantics reduces in many cases the number of attributes that must be handled and explicitly realized during the process execution, but sometimes results in an increase in the burden associated with reading out individual attributes since, according to the type of semantics (implicit children, implicit parents, implicit siblings), not only is it necessary to examine the relevant nodes or end-node of the data tree itself, but possibly all ancestors, descendants or siblings. This is illustrated e.g. for semantics of the type “implicit children” with reference to
The same applies analogously in the case of semantics of the type “implicit parents”, in which the propagation direction for a set attribute from the end-node hierarchy to the root hierarchy indicates necessarily that all descendants of a node must be tested in order to determine its status. The tracing-back direction designated by the arrows in
Finally,
If an attribute on a specific node or end-node of the tree must be set explicitly, this is initially straightforward and independent of the semantics in use. In the case of implicit semantics, however, it is usually necessary to update the data tree in order subsequently to remove redundant entries which are generated by such an operation.
This so-called aggregation of attributes is illustrated by way of example in
In general, the described combination procedure is iteratively repeated until the root node is reached. An example of this is illustrated in
A similar approach is also possible in the case of semantics of the type “implicit parents”. An example of this is illustrated in
Finally,
While the aggregation of the attributes, in the case that a number of attributes must be set, is merely an appropriate but per se optional measure, by which redundant entries can be avoided or eliminated, in the converse case that an existing explicitly or implicitly set attribute must be deleted or removed, when using implicit semantics it is practically always necessary to perform an update in order to eliminate conflicting entries and avoid an erroneous interpretation of the result. Only in the case of explicit semantics does the deletion of an attribute act immediately and directly without any “side effects” on the ancestors, descendants or siblings.
In order to illustrate this, for example, the two attributes indicated by way of arrows (and only these!) must be deleted in the initial state depicted in
In general, the procedure must be iteratively repeated starting from the root. An example for this is shown in
Similar examples are illustrated in
If a new node or a new end-node is to be inserted into an existing tree, which corresponds in the DICOM context to e.g. the creation or insertion of a new data record of the type “instance”, “series” or “study”, it can be agreed in the case of implicit semantics that the attribute value of the newly inserted unit complies with the semantics, i.e. is inherited from the descendants, the ancestors or the siblings, for example. However, it can also be agreed that the new node or end-node is to be inserted with an explicitly predetermined attribute value. In this case, a reorganization of the remaining attributes in accordance with the previously explained propagation and aggregation techniques is generally required. For example,
Finally, it might also be necessary to remove an end-node or a node from the tree completely. In the case of a node, thus its descendants must also be removed. This might also require corresponding reorganization steps in relation to the attributes of the remaining units. A detailed discussion is not required at this point.
Further, elements and/or features of different example embodiments may be combined with each other and/or substituted for each other within the scope of this disclosure and appended claims.
Still further, any one of the above-described and other example features of the present invention may be embodied in the form of an apparatus, method, system, computer program and computer program product. For example, of the aforementioned methods may be embodied in the form of a system or device, including, but not limited to, any of the structure for performing the methodology illustrated in the drawings.
Even further, any of the aforementioned methods may be embodied in the form of a program. The program may be stored on a computer readable media and is adapted to perform any one of the aforementioned methods when run on a computer device (a device including a processor). Thus, the storage medium or computer readable medium, is adapted to store information and is adapted to interact with a data processing facility or computer device to perform the method of any of the above mentioned embodiments.
The storage medium may be a built-in medium installed inside a computer device main body or a removable medium arranged so that it can be separated from the computer device main body. Examples of the built-in medium include, but are not limited to, rewriteable non-volatile memories, such as ROMs and flash memories, and hard disks. Examples of the removable medium include, but are not limited to, optical storage media such as CD-ROMs and DVDs; magneto-optical storage media, such as MOs; magnetism storage media, including but not limited to floppy disks (trademark), cassette tapes, and removable hard disks; media with a built-in rewriteable non-volatile memory, including but not limited to memory cards; and media with a built-in ROM, including but not limited to ROM cassettes; etc. Furthermore, various information regarding stored images, for example, property information, may be stored in any other form, or it may be provided in other ways.
Example embodiments being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2006 034 185.6 | Jul 2006 | DE | national |
