Tony Solomonides

MammoGrid: A Service Oriented Architecture Based Medical Grid Application

The MammoGrid project has recently delivered its first proof-of-concept prototype using a Service-Oriented Architecture (SOA)-based Grid application to enable computing spanning national borders. The underlying AliEn Grid infrastructure has been selected because of its practicality and its emergence as a potential open source standards-based solution for managing and coordinating distributed resources. The resultant prototype is expected to harness the large amounts of medical image data needed to perform epidemiological studies, advanced image processing and ultimately tele-diagnosis over communities of ‘virtual organizations’. This paper outlines the MammoGrid approach in managing a federation of Grid-connected mammography databases in the context of the recently delivered prototype and describes the next phase of prototyping.

Experiences of engineering Grid-based medical software

OBJECTIVES Grid-based technologies are emerging as potential solutions for managing and collaborating distributed resources in the biomedical domain. Few examples exist, however, of successful implementations of Grid-enabled medical systems and even fewer have been deployed for evaluation in practice. The objective of this paper is to evaluate the use in clinical practice of a Grid-based imaging prototype and to establish directions for engineering future medical Grid developments and their subsequent deployment. METHOD The MammoGrid project has deployed a prototype system for clinicians using the Grid as its information infrastructure. To assist in the specification of the system requirements (and for the first time in healthgrid applications), use-case modelling has been carried out in close collaboration with clinicians and radiologists who had no prior experience of this modelling technique. A critical qualitative and, where possible, quantitative analysis of the MammoGrid prototype is presented leading to a set of recommendations from the delivery of the first deployed Grid-based medical imaging application. RESULTS We report critically on the application of software engineering techniques in the specification and implementation of the MammoGrid project and show that use-case modelling is a suitable vehicle for representing medical requirements and for communicating effectively with the clinical community. This paper also discusses the practical advantages and limitations of applying the Grid to real-life clinical applications and presents the consequent lessons learned. CONCLUSIONS The work presented in this paper demonstrates that given suitable commitment from collaborating radiologists it is practical to deploy in practice medical imaging analysis applications using the Grid but that standardization in and stability of the Grid software is a necessary pre-requisite for successful healthgrids. The MammoGrid prototype has therefore paved the way for further advanced Grid-based deployments in the medical and biomedical domains.

Semantic Visualization of Patient Information

Clinical practice and research rely increasingly on analytic approaches to patient data. Visualization enables the comparative exploration of similar patients, a key requirement in certain clinical decision support systems. Patient data is complex and heterogeneous, may have different formats, reside in various structures and carry different semantics. This makes the comparison and analysis of clinical data a challenging task. Most medical applications visualize patient data without integrating additional semantic information to structure the analysis. Our objective is to map patient data onto relevant fragments of ontologies and inferred ontological structures as a basis for improved patient data visualization, comparison, and analysis. Two visualization scenarios that we have implemented using the patient data acquired in the Health-e-Child project will be presented and their clinical evaluation will be provided.

Privacy compliance and enforcement on European healthgrids: an approach through ontology

The sharing of medical data between different healthcare organizations in Europe must comply with the legislation of the Member State where the data were originally collected. These legal requirements may differ from one state to another. Privacy requirements such as patient consent may be subject to conflicting conditions between different national frameworks as well as between different legal and ethical frameworks within a single Member State. These circumstances have made the compliance management process in European healthgrids very challenging. In this paper, we present an approach to tackle these issues by relying on several technologies in the semantic Web stack. Our work suggests a direct mapping from high-level legislation on privacy and data protection to operational-level privacy-aware controls. Additionally, we suggest an architecture for the enforcement of these controls on access control models adopted in healthgrid security infrastructures.

Privacy compliance in european healthgrid domains: An ontology-based approach

The integration of different European medical systems by means of grid technologies will continue to be challenging if technology does not intervene to enhance interoperability between national regulatory frameworks on data protection. Achieving compliance in European healthgrid domains is crucial but challenging because of the diversity and complexity of Member State legislation across Europe. Lack of automation and inconsistency of processes across healthcare organizations increase the complexity of the compliance task. In the absence of automation, the compliance task entails human intervention. In this paper we present an approach to automate privacy requirements for the sharing of patient data between Member States across Europe in a healthgrid [1] domain and ensure its enforcement internally and within external domains where the data might travel. This approach is based on the semantic modelling of privacy obligations that are of legal, ethical or cultural nature. Our model reflects both similarities and conflicts, if any, between the different Member States. This will allow us to reason on the safeguards a data controller should demand from an organization belonging to another Member State before disclosing medical data to them. The system will also generate the relevant set of policies to be enforced at the process level of the grid to ensure privacy compliance before allowing access to the data.

Pattern reification as the basis for description-driven systems

One of the main factors driving object-oriented software development for information systems is the requirement for systems to be tolerant to change. To address this issue in designing systems, this paper proposes a pattern-based, object-oriented, description-driven system (DDS) architecture as an extension to the standard UML four-layer meta-model. A DDS architecture is proposed in which aspects of both static and dynamic systems behavior can be captured via descriptive models and meta-models. The proposed architecture embodies four main elements – firstly, the adoption of a multi-layered meta-modeling architecture and reflective meta-level architecture, secondly the identification of four data modeling relationships that can be made explicit such that they can be modified dynamically, thirdly the identification of five design patterns which have emerged from practice and have proved essential in providing reusable building blocks for data management, and fourthly the encoding of the structural properties of the five design patterns by means of one fundamental pattern, the Graph pattern. A practical example of this philosophy, the CRISTAL project, is used to demonstrate the use of description-driven data objects to handle system evolution.

An Architecture for Semantic Navigation and Reasoning with Patient Data - Experiences of the Health-e-Child Project

Medical ontologies have become the standard means of recording and accessing conceptualized biological and medical knowledge. The expressivity of these ontologies goes from simple concept lists through taxonomies to formal logical theories. In the context of patient information, their application is primarily annotation of medical (instance) data. To exploit higher expressivity, we propose an architecture which allows for reasoning on patient data using OWL DL ontologies. The implementation is carried out as part of the Health-e-Child platform prototype. We discuss the use case where ontologies establish a hierarchical classification of patients which in turn is used to aid the visualization of patient data. We briefly discuss the treemap-based patient viewer which has been evaluated in the Health-e-Child project.

Getting a grasp on virtual reality

This paper describes the development and initial evaluation of a novel system for providing force-feedback to a user’ s’ hand in a virtual environment. The development addresses the problem of providing simple (robust and low cost) but effective sensory cues to assist a user in grasping virtual objects. The approach is to provide approximate but distinctive ‘solidity’ feedback, which together with visual cues creates the sensation of having grasped an object. The initial evaluations indicate that user response is very favorable.

Care Pathway Records with Ontologies: Potential uses in Medical Research and Health Care

This is one of a series of papers arising in part out of the SHARE (Supporting and structuring Healthgrid Activities and Research in Europe) project; in previous work, we have examined the use of integrated care pathways (ICPs), a fine-grained form of medical guideline including the explicit recording of any deviation, or ‘variance’, for research purposes. In particular, we explored how feeding the results of the analysis of variance into the development of a pathway might be an effective way of capturing ‘evidence from practice’. Building on this concept, in our principal case study we propose an information system for extracting data from ICPs using ontologies and a method for inferring ICPs from other patient records, combining these with data collected for retrospective and prospective studies in preimplantation genetic diagnosis (PGD) and screening (PGS) for assisted reproduction. We also look at the problem of selecting alternatives when drug interactions occur when multiple pathways are used in parallel.

Heterogeneous relational databases for a grid-enabled analysis environment

Grid based systems require a database access mechanism that can provide seamless homogeneous access to the requested data through a virtual data access system, i.e. a system which can take care of tracking the data that is stored in geographically distributed heterogeneous databases. This system should provide an integrated view of the data that is stored in the different repositories by using a virtual data access mechanism, i.e. a mechanism which can hide the heterogeneity of the backend databases from the client applications. This paper focuses on accessing data stored in disparate relational databases through a Web service interface, and exploits the features of a data warehouse and data marts. We present a middleware that enables applications to access data stored in geographically distributed relational databases without being aware of their physical locations and underlying schema. A Web service interface is provided to enable applications to access this middleware in a language and platform independent way. A prototype implementation was created based on Clarens (C. Steenberg et. al., 2003), Unity (R. Lawrence and K. Barker, 2000) and POOL (http://pool.cern.ch). This ability to access the data stored in the distributed relational databases transparently is likely to be a very powerful one for grid users, especially the scientific community wishing to collate and analyze data distributed over the grid.