Biomedical subjects

C Combi

Publications and source records attributed to C Combi.

16 recordsLinked to original sources

PubMed1998

WWW-based access to object-oriented clinical databases: the KHOSPAD project.

KHOSPAD is a project aiming at improving the quality of the process of patient care concerning general practitioner-patient-hospital relationships, using current information and networking technologies. The studied application field is a cardiology division, with hemodynamic laboratory and the population of PTCA patients. Data related to PTCA patients are managed by ARCADIA, an object-oriented database management system developed for the considered clinical setting. We defined a remotely accessible view of ARCADIA medical record, suitable for general practitioners (GPs) caring patients after PTCA, during the follow-up period. Using a PC, a modem and Internet, an authorized GP can consult remotely the medical records of his PTCA patients. Main features of the application are related to the management and display of complex data, specifically characterized by multimedia and temporal features, based on an object-oriented temporal data model.

Angioplasty, Balloon, Coronary↗

PubMed1998

Timing is everything. Time-oriented clinical information systems.

Time is important in clinical information systems. Representing, maintaining, querying, and reasoning about time-oriented clinical data is a major theoretical and practical research area in medical informatics. In this nonexhaustive overview, we present a brief synopsis of research efforts in designing and developing time-oriented information systems in medicine. These efforts can be viewed from either an application point of view, distinguishing between different clinical tasks (such as diagnosis versus therapy) and clinical areas (such as infectious diseases versus oncology), or a methodological point of view, distinguishing between different theoretical approaches. We also explore the two primary methodological and theoretical paths research has taken in the past decade: temporal reasoning and temporal data maintenance. Both of these research areas include efforts to model time, temporal entities, and temporal queries. Collaboration between the two areas is possible, through tasks such as the abstraction of raw time-oriented clinical data into higher-level meaningful clinical concepts and the management of different levels of temporal granularity. Such collaboration could provide a common ground and useful areas for future research and development. We conclude with our view of future research directions.

Artificial Intelligence↗

PubMed1997

Temporal reasoning and temporal data maintenance in medicine: issues and challenges.

We present a brief, nonexhaustive overview of research efforts in designing and developing time-oriented systems in medicine. The growing volume of research on time-oriented systems in medicine can be viewed from either an application point of view, focusing on different generic tasks (e.g. diagnosis) and clinical areas (e.g. cardiology), or from a methodological point of view, distinguishing between different theoretical approaches. In this overview, we focus on highlighting methodological and theoretical choices, and conclude with suggestions for new research directions. Two main research directions can be noted: temporal reasoning, which supports various temporal inference tasks (e.g. temporal abstraction, time-oriented decision support, forecasting, data validation), and temporal data maintenance, which deals with storage and retrieval of data that have heterogeneous temporal dimensions. Efforts common to both research areas include the modeling of time, of temporal entities, and of temporal queries. We suggest that tasks such as abstraction of time-oriented data and the handling of different temporal-granularity levels should provide common ground for collaboration between the two research directions and fruitful areas for future research.

Artificial Intelligence↗

PubMed1997

Angiocardiographic digital still images compressed via irreversible methods: concepts and experiments.

We defined, implemented and tested two new methods for irreversible compression of angiocardiographic still images: brightness error limitation (BEL) and pseudo-gradient adaptive brightness and contrast error limitation (PABCEL). The scan path used to compress the digital images is based on the Peano-Hilbert plane-filling curve. The compression methods limit, for each pixel, the brightness errors introduced when approximating the original image (i.e. the difference between the values of corresponding pixels as grey levels). Additional limitations are imposed to the contrast error observed when considering along the scan path consecutive pixels of both the original and the reconstructed image. After previous testing on angiocardiographic images selected as clinically significant from 35 mm films, we enlarged our experiment to a set of 38 coronary angiograms digitally acquired. BEL and PABCEL methods were experimented according to several values of the implied thresholds. Up to a compression ratio of 9:1 for the BEL method and 10:1 for the PABCEL method, no deterioration of the reconstructed images were detected by human observers. After a visual evaluation, we performed a quantitative evaluation. The visualization of pseudo-colour difference images showed the capability of BEL and PABCEL for preserving the most significant clinical details of the original images. For comparison, we applied the JPEG (joint photographic experts group) image-compression standard to the same set of images. In this case, pseudo-colour difference images showed a homogeneous distribution of errors on the image surface. Quantitative compression results obtained by testing the different methods are comparable, but, unlike JPEG, BEL and PABCEL methods allow the user to keep under his direct control the maximum error allowed at each single pixel of the original image. These different behaviors are confirmed by the values obtained for the considered numerical quality quantifiers.

Algorithms↗

PubMed1997

HyperCare: a prototype of an active database for compliance with essential hypertension therapy guidelines.

HyperCare is a prototype of a decision support system for essential hypertension care management. The medical knowledge implemented in HyperCare derives from the guidelines for the management of mild hypertension of the World Health Organization/International Society of Hypertension, and from the recommendations of the United States Joint National Committee on Detection, Evaluation and Treatment of High Blood Pressure. HyperCare has been implemented using Chimera, an active database language developed at the Politecnico di Milano. HyperCare proves the possibility to use active database systems in developing a medical data-intensive application where inferential elaboration of moderate complexity is required.

Databases as Topic↗

PubMed1996

Supporting temporal queries on clinical relational databases: the S-WATCH-QL language.

Due to the ubiquitous and special nature of time, specially in clinical datábases there's the need of particular temporal data and operators. In this paper we describe S-WATCH-QL (Structured Watch Query Language), a temporal extension of SQL, the widespread query language based on the relational model. S-WATCH-QL extends the well-known SQL by the addition of: a) temporal data types that allow the storage of information with different levels of granularity; b) historical relations that can store together both instantaneous valid times and intervals; c) some temporal clauses, functions and predicates allowing to define complex temporal queries.

Anesthesiology↗

PubMed1995

ARCADIA: a system for the integration of angiocardiographic data and images by an object-oriented DBMS.

Use of data base techniques to store medical records has been going on for more than 40 years. Some aspects still remain unresolved, e.g., the management of textual data and image data within a single system. Object-orientation techniques applied to a database management system (DBMS) allow the definition of suitable data structures (e.g., to store digital images): some facilities allow the use of predefined structures when defining new ones. Currently available object-oriented DBMS, however, still need improvements both in the schema update and in the query facilities. This paper describes a prototype of a medical record that includes some multimedia features, managing both textual and image data. The prototype here described considers data from the medical records of patients subjected to percutaneous transluminal coronary artery angioplasty. We developed it on a Sun workstation with a Unix operating system and ONTOS as an object-oriented DBMS.

Angiocardiography↗

PubMed1995

Querying temporal clinical databases with different time granularities: the GCH-OSQL language.

There is a need for managing temporal clinical information given at different levels of granularity. Different time granularities are also needed in querying clinical databases. In this paper, we describe GCH-OSQL (Granular Clinical History--Object Structured Query Language), an object-oriented temporally-oriented extension of SQL. GCH-OSQL is based on an object-oriented temporal data model. It allows storage of clinical information at different and mixed granularities. GCH-OSQL deals with the valid time of clinical information. GCH-OSQL offers also a graphical user-interface. It guides different end users, from expert to naive, to formulate expressive and correct queries.

Computer Graphics↗

PubMed1995

Managing different time granularities of clinical information by an interval-based temporal data model.

In the field of databases, time management at different levels of granularity has been an issue for several years, for instance when dealing with clinical information from different databases using different time units, dealing with natural language expressions, or when dealing with temporal uncertainty. A temporal data model is proposed to manage the temporal aspect of data, presented at various and mixed levels of granularity. The concept of temporal assertions shapes the entire temporal information. The model provides a temporal dimension to the data by using intervals that can be specified at different granularities. The model supports a three-valued logic, where True, False and Undefined are the truth values. The temporal data model allows to manage some degrees of uncertainty when establishing temporal relationships between intervals or between temporal assertions, expressed at different granularities. The logical connectives and quantifiers can manage each of the three truth-values. We applied the temporal data model by implementing an object-oriented database system for managing follow-up clinical data from patients who underwent percutaneous transluminal coronary angioplasty.

Databases, Factual↗

PubMed1994

A database schema for public-domain medical software.

The quantity of public-domain medical software available is huge, and a classification schema may be therefore helpful. We developed a schema that includes identification data (name of the software, author, etc.), description (hardware and software requirements), classification (software category, application domain, etc.) and evaluation data (external quality and internal quality factors). The schema was tested on the public-domain software available at the SCAMC meetings (about 36 Mb). We also classified the software by employing students from a master course in computer science and medical informatics. We stored the high quantity of information collected in a database we developed using Paradox.

Databases, Factual↗

PubMed1994

Some experiments in compressing angiocardiographic images according to the Peano-Hilbert scan path.

We defined and implemented three new irreversible compression techniques for digital angiocardiographic static images: brightness error limitation (BEL), pseudo-gradient adaptive brightness error limitation (PABEL), pseudo-gradient adaptive brightness and contrast error limitation (PABCEL). To scan digital images we implemented an algorithm based on the Peano-Hilbert plane filling curve. We applied our compression techniques to 168 static images selected from angiocardiographic 35-mm films. We achieved best compression results applying the PABCEL method, obtaining a mean compression ratio of about 8:1. Consulted cardiologists did not find significant diagnostic differences between original images and reconstructed ones.

Algorithms↗

PubMed1994

Managing and displaying different time granularities of clinical information.

We approach the need of representing by powerful graphical user-interface the granularity of the temporal clinical information. In this work we present some contributions, to suitably display such temporal clinical information. The graphical representation relies on a temporal clinical data model able to manage data having different granularities.

Computer Graphics↗

PubMed1992

MS2/Cardio: towards a multi-service medical software for cardiology.

Many clinics are interested to use software packages in daily practice, but lack of integration of such packages seriously limits their scope. In practice this often entails switching between programs and interrupting the run of an individual program. A multi-task approach would not solve this problem as it would not eliminate the need to input the same data many times, as often occurs when using separate packages. The construction of a Multi-Service Medical Software package (MSx2) is described, which was also developed as an example of practical integration of some clinically relevant functions. The package runs on a personal computer in an MS-DOS environment and integrates a time-oriented medical record management unit (TOMRU) for data of ambulatory patients, and a drug information management unit (DIMU) concerning posology, content, effects, and possible interactions. Of the possible database configurations allowed by MSx2, the cardiology patient database (MSx2/C) and hypertensive patient database (MSx2/H) were developed and described here. Clinical information to be included in the configurations was obtained after discussion and consensus of clinical practitioners. MSx2/C was distributed to several hundred clinical centers during computerized courses to train future users. MSx2 can easily transfer patient data to statistical processing packages.

Ambulatory Care Information Systems↗

PubMed1991

Dissemination, standardization and user-flexibility in implementing TOMRs for cardiology.

A great many clinics are interested in using software programs in daily practice. We report on the construction of a time oriented medical record unit (TOMRU). It runs on MS-DOS personal computers. TOMRU handles the follow-up data of ambulatory patients. Of the possible database customizations allowed by TOMRU, the cardiology patient database (TOMRU/C) and hypertensive patient database (TOMRU/H) were developed and are described here. Customizing TOMRU should in any case be left to an expert user, in charge of database management. The clinical information to be included in the customizations was obtained by discussing the needs of and obtaining the consensus of clinical practitioners. TOMRU/C was handed over to some hundreds of clinical centres during the computerized itinerant courses held to train users.

Ambulatory Care Information Systems↗

PubMed1989

Data compression applied to dynamic electrocardiography.

We have tested some techniques of ECG compression on the BIH/MIT Arrhythmias database. We have applied the following methods: (1) method of differences; (2) compression by prediction; (3) sample skipping methods; with the following kinds of errors: amplitude error, amplitude and delay error, area error. In the first and second method the average code length found after application of the Huffmann encoding has been found to be about 4 bits sample-1. For the third method the final compression ratio varies according to the allowed error; with a limited error threshold, however, we have reached an average compression a little lower than 1:5.

Ambulatory Care↗

PubMedDate not supplied

Object-orientated DBMS techniques for time-oriented medical record.

In implementing time-orientated medical record (TOMR) management systems, use of a relational model played a big role. Many applications have been developed to extend query and data manipulation languages to temporal aspects of information. Our experience in developing TOMR revealed some deficiencies inside the relational model, such as: (a) abstract data type definition; (b) unified view of data, at a programming level; (c) management of temporal data; (d) management of signals and images. We identified some first topics to face by an object-orientated approach to database design. This paper describes the first steps in designing and implementing a TOMR by an object-orientated DBMS.

Algorithms↗