Structured Data Management-the Design and ...

Structured Data Management-the Design and Implementation of a Web-based Video Archive Prototype H. Zou, PhD, Q.C. Lu, MS', J.C. Durack, MD, C. Chao, MS2, H.R. Strasberg, MD, MS, Y. Zhang, MS', M.Tsai, PhD, K. Melmon, MD, J.S. Hahn, MD3 SKOLAR, Inc. Palo Alto, CA 1 Computer Science Dept., 2Electrical Engineering Dept.

Stanford University 3Neurology Dept., Stanford University School of Medicine

Abstract In response to the lack of readily available multimedia rich medical knowledge sources to support medical education and patient care, we designed and implemented a web-based video publishing platform. In order to promote the development of high-quality, up-to-date educational content, we have devised a scalable structure that allows online submissions and continuous updating of video and accompanying textual descriptions. Our goal is to enable experts in varied medical domains to collaborate in the construction of a video library using an intuitive web-based interface. Neurologists at Stanford built a well-annotated neurology video collection that initially emphasized childhood and adult movement disorders. The collection may be accessed either as a stand-alone resource or as part of the Stanford SkolarTm MD, an integrated online medical knowledge provider. This manuscript discusses the design framework and implementation details of structured media content development. We present examples illustrating media data collection, content indexing using UMLS concepts, media storage, and web presentation.

As broad bandwidth Internet connectivity becomes accessible and video-streaming software matures, the creation of web-based video collections to supplement text reference sources becomes feasible. An integrated system with attributes described above will add tremendous value to learners of medicine.

We initially chose to develop a collection of neurological movement disorders since motion video serves as a superior learning tool compared to written descriptions. We deemed it essential to create a video publishing platform flexible enough to support on-going collection of new material from diverse and trusted knowledge sources. As such, we would like to promote the concept of online collaboration within and across multiple knowledge domains. This paper discusses the strategy for developing a pleuripotent software tool and a structured media management system ranging from content collection, indexing, storage, and database management, to final display.

Methods Streaming videos: Videos in this project were encoded into RealMedia files using Real Producer and Surestream technology from RealNetworks. Video content was uploaded onto a server using a standard file-transfer protocol (FTP). Acceptable compression levels vary by intended users depending on the resolution of video information needed in a specific domain (e.g. specialists versus primary care physicians). A recent study concluded that the bandwidth needed for most real-time, video-based consultations fall in the range of 128 kbps to 384 kbps, depending on the rate of motion in the video.2 We decided that minimal encoding speed of 150 kbps was necessary to show the subtleties of movement disorders in neurology.

Introduction Medicine relies heavily on visual information. A written paragraph is simply inadequate to describe complex radiologic images, multidimensional neurological movement disorders, echocardiograms, angiograms, endoscopic images, or surgical procedures. Modem medical teaching utilizing webbased media rich resources is in its nascency and has not established its efficiency and efficacy. Web-based medical knowledge sources have grown exponentially over the past several years. Stanford Skolar MD' (formerly SHINE) was built to address the information needs of health care professionals. Studies have shown that physicians desire an information system that is simple, easy to pose questions, searches a variety of resources in parallel, provides an easy-to-comprehend presentation, and allows rapid and intuitive navigation across highquality contextual information.

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Problems and proposed solutions 1) Re-usable software The most conventional approach of building an online media archive often leads to a medical content tightly coupled with the software. This limits the

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ability by other authors to easily expand the existing media content or build archives in other domains. Our goal was to avoid a project-centric approach in favor of structured content management.3

In addition to the demand for new functionalities, reengineering often is necessary when new databases or programming languages are adopted in the future. Code re-usability and retro-compatibility become necessities. Here we take a four-layer design approach and divide the project into the following

2) Designing a dynamically updated multimedia resource Knowledge dissemination by way of traditional textbook or journal publications is hampered by the delay from initial submission to final publication. The connectivity of web-based systems presents new opportunities to approach this problenm The Internet supports dynamic content evolution, rather than static publication. Therefore, we have implemented a webserver based architecture with intuitive interfaces for contributors to upload new media content; editors to update annotations; and reviewers to ensure the quality of the content (Figure 1). We believe that the cumulative nature of a dynamic system enables an active and diverse medical community to build an archive collectively. Media Developers Software Tools

pieces (Table 1): 1. At the top level lies graphical user interface (GUI) viewed on standard web-browsers. Included here are web pages for media browsing, searching, uploading and editing. This layer also defines the workflow design. The linkages between various GUIs are defined, such as how an editor might assign a diagnosis to a video. 2. The second layer abstracts components necessary for a media collection systenm The logic relationships between components are defined, as well as their utility. The most frequently defined objects here are disease diagnoses and media content. The object relationships may be complex, for example, each diagnosis may have multiple videos depicting different manifestations, severities or variants while one video may depict more than one disease entity with singular or overlapping clinical signs. 3. The third layer separates database structure from the component objects, and thus serves as an interface layer. The interface defines SQL queries to support desired actions (e.g., assigning videos to specific diagnoses) and provides the tools for saving and retrieving information from the database. 4. At the lowest level lies the raw data/database layer, where the database tables and relational schemes are defined.

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Figure 1. Components of a dynamic video publishing platform. A variety of video collections are ultimately accessible by end-users either through browsing or performing a search.

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Table 1. Layered modular programming scheme

3) Layered modular programming scheme Modem software development favors a divide and conquer approach to solve a sophisticated problenm4 Our video platform requires the following functionalities: 1. Data collection channels accessible by contributors, editors and reviewers. 2. Database construction: Multiple relational tables keeping track of the relationships between video content and descriptive diagnosis information. 3. Search finctions: Videos and their annotations should be searchable when text queries are entered. 4. Flexible data presentation: Sorting, grouping and display of videos and written content.

An object-oriented database design is well suited to support these functions and hide implementation

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4) Structured media collection A central organizational scheme is desirable to enable multiple authors to seamlessly incorporate new material and keep abreast of each other's work. This also allows collaborative editing and updating. We used a central hierarchical tree structure that is editable, that is, new branches can be created or modified while old nodes can be trimmed using our Tree Editor. In the neurology domain we used a

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facilitate medical concept-based searches for more efficient and satisfactory information retrieval (Figure 3).

custom-made tree structure consisting of diagnoses and their assigned videos, but other structured hierarchies can be used. Our tree includes two kinds of nodes: leaves and intermediate nodes. The leaves house diagnoses, while the nodes are categories containing either leaves or sub-categories or both (Figure 2).

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Figure 3. Part of the Diagnosis Editor showing an example of assigning UMLS concept names and CUI to the diagnosis. Results Video Archive of Movement Disorders Neurologists here at Stanford tested our system and successfully created a movement disorder video archive including a total of 45 diseases (Figure 4). Our video platform is currently being extended to new topics in neurology and cardiology.

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Schematic diagram of the hierarchical tree

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Each time a new video is submitted, the contributor selects a diagnosis from the hierarchical tree to be assigned to the video. If a desired diagnosis does not exist the contributor adds the new diagnosis to the tree in its appropriate hierarchical position. This way, any new video clip and its associated diagnosis will establish an appropriate relationship with the existing items in the browsing tree. The browsing tree is also important in organizing the video archive when end-users use it as a browse-only system.

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ther differential diagnosis Infonnatlon: The diagnosis of Paricinson's disease is a inical one, although excluding other entities presenting as pasicinsonisn is indicated at mes.

Whenever possible, we used Unified Medical Language System (UMLS) concept terms are used to There are assign diagnoses video content. advantages to using a controlled vocabulary to generate a hierarchical tree of diagnoses corresponding to content in the video collection. Since our Tree Editor is fully editable future adoption of newer versions of standard medical vocabularies can be easily achieved. A further benefit to indexing by structured hierarchical vocabulary would be the ability to automatically insert new video content directly into an existing contextual framework.

Figure 4. Presentation of video and its supporting descriptive text (Parkinson Disease). "Other videos linked to the disease" directs users to the 3 additional video clips of Parkinson Disease. The numeric hyperlinks under differential diagnosis (right lower comer) point to additional content on Multiple System Atrophy and Progressive Supranuclear Palsy for comparison.

Organizational scheme of neurology video archive The hierarchical tree, which represents knowledge in the neurology domain, is useful for organizing a large number of diagnoses into a central schema. Furthermore, by traversing its branches users are able to browse the categories of neurological diseases and to determine the range of content in the collection. For the neurological video archive, we created a toplevel branch: neurological disease browsing tree that follows a clinical classification. The movement disorder branch is a subcategory of neurological disease (Figure 5).

5) Unified Medical Language System @ Indexing We chose to index the neurology video collection using UMLS concepts. We previously designed a mechanism7 and implemented an interface enabling editors to select UMLS Metathesaurus concepts and the associated Concept Unique Identifier (CUI) for each diagnosis. Indexing in this fashion will

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Figure 5. Example of the Movement Disorder Browsing Tree by disease classification. Numeric hyperlinks lead to the associated videos.

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Searchable video archive In our video archive, search results are displayed in a hierarchical format for quick determination of their clinical context (Figures 6, 7). Users may query our video collection by disease name (Figure 6) or neurological signs (Figure 7). For example, a user may encounter a patient with Huntington Disease. A search for 'Huntington Disease' finds videos containing the various manifestations of the disorder. The user may also search for 'chorea' and look for various diseases that are associated with this neurological sign.

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Figure 7. Search by neurological signs. The term 'chorea', e.g., results in several diseases that are related to the tenn.

Hyperlinks to Differential Diagnoses Cross-referencing provided through hyperlinks offers additional means for navigation (Figure 4). One obvious application is to use hyperlinks to connect all the differential diagnoses (DDX). We implemented an easy-to-use method to create hyperlinks to the DDX. By choosing one or more DDX from the hierarchical disease tree, the editor automatically creates these hyperlinks.

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Discussion Web media publishing platform Modem academic healthcare centers may help to satisfy many information needs by providing web access to their digital resources.8 In order to highlight the value of media rich medical knowledge sources, we designed and implemented a platform to support online video publishing. Stanford neurologists successfully used it to build a working prototype of neurology video archive in the relatively short period of 12 months. The unique features of our system include a re-usable platform (e.g., a cardiology branch can be easily built into the video archive) and

dynamic content development with scalable customdesigned infrastructure (Figure 8). UMLIS+ Conice

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evaluate precision, recall and accuracy for conceptassigned versus text-description based video retrieval.

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Conclusion We selected neurological movement disorders to illustrate a conmwehensible strategy for designing and implementation of a web-based, scalable media platformm We believe that a structured media management system and layered modular implementation are essential. Future studies will focus on conceptbased search and the value of a fully searchable media rich database for expanding point-of-practice access and facilitating medical education, especially when used in the context of an integrated online medical knowledge system such as Stanford Skolar MD. We believe that our model of building from the collective effort of medical experts, rather than relying on isolated individuals, will be proven to be efficient and effective. In the near future we hope to determine the efficacy of this tool in medical

ra,.hialTrel Figure 8. Overall database scheme.

The browsing tree is the organizational corner stone of the video archive: based on its hierarchy, the video database is collected, maintained and displayed in a logical way.

education. References 1. Hubbs PR. Tsai M, Dev P et al. The Stanford Health Education Network for Education: integrated information for decision maldng and learning. Proceedings of the 1997 AMIA Annual Fall Symposium, 505-508. 2. Networking Health Prescriptions for the internet. 2000. National Research Council, National Academy Press, Washington D.C. p72-77. 3. Constantinou P, Mather R, and Dev P. 1995 The Interactive Image Tool: Adding Structure to Images. Proceedings - the Annual Symposium on Computer Applications in Medical Care:508-J1. 4. Nathan Wallace. Design Pattems in Web Programming 2000.

In order to facilitate the merging of two archives, future endeavor includes designing an automated insertion process. In a hierarchical tree, a new video tagged with a UMLS GUI can be added to an existing node or added to new node automatically based on structured vocabulary such as SNOMED.

Modular programming scheme resources We believenowthat~~~~~inciiaus.Ifitewrweil identifying the fundamental building blocks and designing a logical database mnanagement system were keys to successful implementation of our video platformi. To ensure migration from one generation of design to the next with' miiinimal inconvenience, the overall task is segmented into smaller and more manageable layered modules.9 Once we define standardized interfaces between each layer, any implementation changes in a specific layer will be confined within that layer. It also makes it possible for multiple programmners to work in parallel because it conceals imnplementation details within each layer.

http://www.e-gineer.comLaarticles/desigL-patterns-in-web-

progamming.html. 5. Douglas C. Schmidt. Using Design Patterns to Develop Reusable Object-Oriented Software. ACM Computing Surveys 28A(4). 1996. http://www.acm.org/surveys/1996/ 6. UMLS documentation: http://www.nlm.nih.gov /research /umls/META2. HTML#s23. 7. Wang J, Yan J, Strasberg et al. Versatile User Interface Using UMLS Metathesaurus, 2000. AMIA Annual Symp. 8. Westberg EE, and Miller R.A. 1999. The Basis for using the Internet to Support the Information Needs of Primary Care. Review. J. of the AMIA Vol. 6, Num.1, p 6-25. 9. Parnas D. On the criteria to be used in decomposing systems into modules. Commun. of the ACM, 15, 12 (1972) 1053-1058. 10. Lancaster FW. Evaluation of the MEDLARS Demand Search Service. Bethesda, MD. National Library of Medicine. 1968. 11. Kirby M, and Miller N. Medline searching on Colleague: reasons for failure or success of untrained users. 1986. Med Ref Serv Q, 5:17-34. 12. Kingsland LC, Harbourt AM, Syed EJ, and Schuyler PL. 1993. Coach: applying UMLS knowledge sources in an expert searcher environment. Bull Med Libr Assoc, 81: 178-183. 13. Mitchell JA, Johnson ED, Hewett JE, and Proud VK. 1992. Medical students using Grateful Med: analysis of failed searchers and a six-month follow-up study. Comput Biomed Res, 25: 43-55.

Concept-based search model Analysis of failed searches showed that failures were most likely due to incorrect indexingl0 or failure to use appropriate search terms.' 11-13 We propose to exploit UMLS concept names for video database indexing, as well as employing a concept based search engine. The UMLS combines many lexical

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