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Biomedical subjects

J F Brinkley

Publications and source records attributed to J F Brinkley.

At least 19 recordsLinked to original sources
PubMed1998

The digital anatomist foundational model: principles for defining and structuring its concept domain.

We define a foundational model as an abstraction of a body of knowledge that explicitly declares the principles and concepts necessary for coherently and consistently modelling a knowledge domain. Principles for a foundational model of anatomy are defined and used to specify the components of such a model. These components include an anatomy ontology (Ao), an anatomical structural abstraction (ASA), an anatomical transformation abstraction (ATA) and metaknowledge (Mk), which comprises the rules for representing relationships in the other three components of the model. The foundational model Fm is therefore specified as the four-tuple Fm = (Ao,ASA,ATA,Mk). We hypothesize that this abstraction captures the information that is sufficient and necessary for describing the anatomy of any physical entity that constitutes the body, as well as that of the body itself.

Anatomy↗
PubMed1998

Requirements for an on-line knowledge-based anatomy information system.

User feedback from the Digital Anatomist Web-based anatomy atlases, together with over 20 years of anatomy teaching experience, were used to formulate the requirements and system design for a next-generation anatomy information system. The main characteristic of this system over current image-based approaches is that it is knowledge-based. A foundational model of anatomy is accessed by an intelligent agent that uses its knowledge about the available anatomy resources and the user types to generate customized interfaces. Current usage statistics suggest that even partial implementation of this design will be of great practical value for both clinical and educational needs.

Anatomy, Artistic↗
PubMed1998

Incorporating constraint-based shape models into an interactive system for functional brain mapping.

Through intraoperative electrical stimulation mapping, it is possible to identify sites on the surface of the brain that are essential for language function. Interesting correlations have been found between the distribution of these sites and behavioral traits such as verbal IQ. In previous work, tools were developed for building a reconstruction of a patient's cortical surface and using it to recover coordinates of essential language sites. However, considerable expertise was required to produce good reconstructions. This paper describes an improved version of the mapping procedure, in which segmentation is driven by a 3-D shape model. The model-based approach provides more intuitive control over the system, allowing a trained user to complete a surface reconstruction and mapping in about two hours. This level of performance makes it feasible to gather language maps for a large number of patients, which hopefully will lead to significant new findings about language organization in the brain.

Anatomy, Cross-Sectional↗
PubMed1997

The digital anatomist information system and its use in the generation and delivery of Web-based anatomy atlases.

Advances in network and imaging technology, coupled with the availability of 3-D datasets such as the Visible Human, provide a unique opportunity for developing information systems in anatomy that can deliver relevant knowledge directly to the clinician, researcher or educator. A software framework is described for developing such a system within a distributed architecture that includes spatial and symbolic anatomy information resources, Web and custom servers, and authoring and end-user client programs. The authoring tools have been used to create 3-D atlases of the brain, knee and thorax that are used both locally and throughout the world. For the one and a half year period from June 1995-January 1997, the on-line atlases were accessed by over 33,000 sites from 94 countries, with an average of over 4000 "hits" per day, and 25,000 hits per day during peak exam periods. The atlases have been linked to by over 500 sites, and have received at least six unsolicited awards by outside rating institutions. The flexibility of the software framework has allowed the information system to evolve with advances in technology and representation methods. Possible new features include knowledge-based image retrieval and tutoring, dynamic generation of 3-D scenes, and eventually, real-time virtual reality navigation through the body. Such features, when coupled with other on-line biomedical information resources, should lead to interesting new ways for managing and accessing structural information in medicine.

Anatomy↗
PubMed1997

Managing medical research data with a Web-Interfacing Repository Manager.

This paper describes the Web-Interfacing Repository Manager (WIRM), a perl toolkit for managing and deploying multimedia data, which is built entirely from free, platform-independent components. The WIRM consists of an object-relational API layered over a relational database, with built-in support for file management and CGI programming. The basic underlying data structure for all WIRM data is the repository object, a perl associative array whose values are bound to a row of a table in the relational database. Based on our experience implementing a target application (the Brain Mapper Console), we describe five stages through which a system passes as it evolves from a primitive file hierarchy to a full-fledged repository console.

Brain Mapping↗
PubMed1997

Using 3-D shape models to guide segmentation of MR brain images.

Accurate segmentation of medical images poses one of the major challenges in computer vision. Approaches that rely solely on intensity information frequently fail because similar intensity values appear in multiple structures. This paper presents a method for using shape knowledge to guide the segmentation process, applying it to the task of finding the surface of the brain. A 3-D model that includes local shape constraints is fitted to an MR volume dataset. The resulting low-resolution surface is used to mask out regions far from the cortical surface, enabling an isosurface extraction algorithm to isolate a more detailed surface boundary. The surfaces generated by this technique are comparable to those achieved by other methods, without requiring user adjustment of a large number of ad hoc parameters.

Anatomy, Cross-Sectional↗
PubMed1996

Visualization and mapping of neurosurgical functional brain data onto a 3-D MR-based model of the brain surface.

The Human Brain Project was initiated with the goal of developing methods for managing and sharing information about the brain. As a prototype Human Brain Project application we are developing a system for organizing, visualizing, integrating and sharing information about human language function. The goal of the brain mapping component of our work, described in this article, is to generate the 3D location and extent of cortical language sites with respect to a uniform, 3D patient coordinate system. The language sites of individual patients can then be combined with or related to other patient data in terms of a Talairach, surface-based, or other deformable coordinate systems. Language site mapping is done by visually comparing an intraoperative photograph with the rendered image (from MRI data). The techniques outlined in this article have been utilized to map cortical language sites of six patients. Preliminary results point to the adequacy of our volume visualizations for language mapping. The strength of the visualization scheme lies in the combination of interactive segmentation with volume and surface visualization. We are now in the process of acquiring more patient data to further validate the usefulness of our method.

Brain Mapping↗
PubMed1996

A Web-based repository manager for brain mapping data.

The Web provides a rapid prototyping environment for building platform-independent graphical user interfaces. A Web-based console can be implemented as a suite of CGI scripts that generate HTML code, manipulate files, execute system commands, and invoke external tools. Often these tools share data by reading and writing flat files, which must be explicitly maintained by the CGI programmer. In a repository system, meta-data about each file object are maintained in a database, and access to all data is regulated by a layer of control services. This paper describes the design and implementation of a Web-based Repository Manager (WRM), which provides an application programmer's interface for controlling applications, generating HTML documents, handling Web forms, and managing multi-media data. The WRM is being used to develop a console for the Brain Mapping Framework, a system for visualizing cortical stimulation data obtained during neurosurgery.

Brain Mapping↗
PubMed1995

Web-based access to an online atlas of anatomy: the Digital Anatomist Common Gateway Interface.

A World Wide Web Common Gateway Interface package is described for accessing existing online interactive atlases of anatomy. The Web interface accesses the same 2-D and 3-D images of human neuroanatomy, knee anatomy and thoracic viscera that are currently accessed by a custom interactive atlas in distance learning courses. Although the Web interface is too slow to replace the existing atlas, it provides a parallel access path that has much broader potential for development of a distributed distance learning network in anatomy. By maintaining both access methods to the same information sources we continue to satisfy the fast interactivity needs for our local courses, while at the same time providing a migration path to the Web as the capabilities of Web browsers evolve.

Anatomy, Artistic↗
PubMed1995

Enhancements of anatomical information in UMLS knowledge sources.

Although anatomical terminology forms a part of biomedical structured vocabularies, available sources lack the requisite granularity, semantic types and relationships for comprehensively and consistently representing anatomical concepts in machine readable form. Thoracic angiology was selected as a proof of concept experiment for in depth representation of symbolic information in gross anatomy through the enhancement of semantic types, concepts and relationships in UMLS. Provided the representation of concepts is comprehensive, hierarchies generated with four types of simple relationships are capable of displaying anatomical information from the systemic view point with sufficient detail to meet the needs of applications in basic science education and in the practice of surgical subspecialties.

Anatomy↗
PubMed1994

Performance evaluation of a distance learning program.

This paper presents a performance metric which uses a single number to characterize the response time for a non-deterministic client-server application operating over the Internet. When applied to a Macintosh-based distance learning application called the Digital Anatomist Browser, the metric allowed us to observe that "A typical student doing a typical mix of Browser commands on a typical data set will experience the same delay if they use a slow Macintosh on a local network or a fast Macintosh on the other side of the country accessing the data over the Internet." The methodology presented is applicable to other client-server applications that are rapidly appearing on the Internet.

Computer Communication Networks↗
PubMed1993

A flexible, generic model for anatomic shape: application to interactive two-dimensional medical image segmentation and matching.

A representation called a radial contour model (RCM) is described for two-dimensional anatomic shapes. The model, which is a type of a geometric constraint network (GCN), is both flexible, in that it can deform to fit a particular instance of an anatomic shape, and generic, in that it captures all examples of a particular anatomic shape class. The model is implemented in a program, called SCANNER (version 0.7), for interactive model-based two-dimensional image segmentation and matching. Use of the model allows the segmenter to direct the search for edges in the image, and to fill in edges where none are present. Evaluations were done using models of 15 cross-sectional shapes appearing on CT images from 16 patients. Results from 480 trials show that the model-based approach reduces segmentation time by nearly a factor of 3 over manual methods, and correctly classifies 72.9% of the contours. The results not only suggest that the RCM will be useful for several current medical image segmentation tasks, but also support the hypothesis that geometric constraint networks are a viable approach to anatomic shape representation.

Artificial Intelligence↗
PubMed1993

Knowledge-based client-server approach to structural information retrieval: the Digital Anatomist Browser.

Structural information can be defined as data and knowledge about biological objects ranging in size from molecules to the whole body. A framework is described for organizing structural information around a well-defined set of terminology and semantic relationships, and for disseminating multimedia structural information by means of a wide-area information server that is accessible over the internet. A Macintosh-based client of this server, called the Digital Anatomist Browser, has been used to teach neuroanatomy for the last 2 years. The client-server approach provides each student unlimited access to a rapidly growing knowledge base of structural biology that, while immediately useful for anatomy teaching, has the potential to be an organizing framework for other kinds of medical knowledge as well.

Artificial Intelligence↗
PubMed1993

Probabilistic constraint satisfaction with structural models: application to organ modeling by radial contours.

One of the key challenges within medical information sciences is the development of useful models for biological structure and its variability. Many biomedical problems involve the elucidation of structure (for example, from experimental data or from imaging studies), and structural models can often drive the process of inferring precise structure from data. Ideally, model-driven data interpretation combines knowledge about the generic features of a class of biological structures (as contained within a model) with data that provide specific information (often noisy) about a particular instance of the class. In this paper we briefly discuss model-driven determination of biological structure as an example of a structural constraint satisfaction problem. We describe a probabilistic implementation of structural constraint satisfaction, and show that our formulation of a particular organ modeling technology (Radial Contour Models) exhibits promising performance. Our results demonstrate the utility of probabilistic models for the solution of structural constraint satisfaction problems.

Computer Simulation↗
PubMed1993

A network model for wide area access to structural information.

Structural information in medicine is information about the physical body. Recent advances in medical imaging and biotechnology have greatly increased the amount and importance of structural information, and advances in networking envisioned by the High Performance Computing and Communication Initiative (HPCC) will allow this kind of information to be delivered to remote clients over wide area networks. One of the most important factors determining the usability of such a client-server configuration is the time delay between the request for information from the server, and its presentation to the user at the client. In this paper we present a model for predicting the performance of a structural information client based on the ping time, a simple, unobtrusive network measurement. Preliminary results suggest that the relationship between ping time and transfer time for large files is linear, which if borne out by more data, will allow the performance of structural information clients at remote sites to be predicted without the expense of installing them first. At the same time, such a model will be useful for planning improvements to the network in those sites which could most benefit by wide area access to structural information.

Computer Communication Networks↗
PubMed1992

Hierarchical geometric constraint networks as a representation for spatial structural knowledge.

A representation is proposed for capturing generic spatial knowledge about classes of objects in a structural hierarchy of biology. The basic premise is that spatial properties such as shape and relative relationships can be expressed as networks of interacting constraints. The representation is defined, partial implementations that demonstrate practical utility are described for model based organ and protein structure determination, and research issues are presented that must be solved before the representation can be implemented in its entirety. As these issues are resolved the representation will find increasing utility as the foundation for a spatial knowledge base of structural biology.

Computer Simulation↗
PubMed1991

Spatial anatomic knowledge for 2-D interactive medical image segmentation and matching.

A representation is described for two-dimensional anatomic shapes which can be described by single-valued distortions of a circle. The representation, called a radial contour model, is both generic, in that it captures the expected shape as well as the range of variation for an anatomic shape class, and flexible, in that the model can deform to fit an individual instance of the shape class. The model is implemented in a program called SCANNER (version 0.61) for 2-D interactive image segmentation and matching. An initial evaluation was performed using 7 shape models learned from a training set of 93 contours, and a control model containing no shape knowledge. Evaluation using 60 additional contours showed that in general the shape knowledge should reduce interactive segmentation time by a factor of two over the control, and that for specific shapes such as the eye, the improvement is much greater. A matching function was also devised which showed that the radial contour model should allow diagnosis of subtle shape changes. These results suggest that the use of spatial anatomic knowledge, when combined with good interactive tools, can help to alleviate the segmentation bottleneck in medical imaging. The models, when extended to more complex shapes, will form the spatial component of a knowledge base of anatomy that could have many uses in addition to image segmentation.

Artificial Intelligence↗