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Biomedical subjects

C E Kahn

Publications and source records attributed to C E Kahn.

At least 19 recordsLinked to original sources
PubMed2001

A Bayesian network for diagnosis of primary bone tumors.

The authors developed a Bayesian network to differentiate among five benign and five malignant neoplasms of the appendicular skeleton using the patient's age and sex and 17 radiographic characteristics. In preliminary evaluation with physicians in training, the model identified the correct diagnosis in 19 cases (68%), and included the correct diagnosis among the two most probable diagnoses in 25 cases (89%). Bayesian networks can capture and apply knowledge of primary bone neoplasms. Further testing and refinement of the model are underway.

Bayes Theorem↗
PubMed2000

Design and implementation of an Internet-based health information resource.

In support of its institutional mission of community service, the Medical College of Wisconsin created a digital library of health information. This Internet-based resource, named MCW HealthLink, provides health news and information geared to patients, their family members, and the community at large. Information is delivered through a World Wide Web site and an e-mail newsletter. The web and e-mail components are integrated to maximize their utility to readers. This article describes the philosophy, design and implementation of the resource. Ongoing efforts include development of a health information resource tailored to the needs of individual readers.

Community Health Services↗
PubMed1999

Applicability of American College of Radiology appropriateness criteria in a general internal medicine clinic.

OBJECTIVE: The American College of Radiology (ACR) Appropriateness Criteria for Imaging and Treatment Decisions are intended to help radiologists and referring physicians use imaging procedures appropriately and cost-effectively, but these criteria have not undergone empirical testing. To assess how readily the ACR appropriateness criteria can be applied to clinical practice, we retrospectively examined their applicability in a general ambulatory care setting. MATERIALS AND METHODS: From all requests during an 8-month period for noninterventional CT, sonography, MR imaging, and nuclear medicine imaging procedures received from a general internal medicine clinic, we excluded cases for which relevant clinic notes were unavailable or incomplete. Three experienced radiologists classified cases by consensus, using data from radiology requests and clinic notes. Cases were classified as a "complete match" if the features matched a clinical condition and variant included in the ACR appropriateness criteria; as a "partial match" if the features matched a clinical condition but did not match all features of a variant; or as "unmatched." RESULTS: Of 316 cases, there were 202 complete matches (64%) and 37 partial matches (12%). Of the 77 unmatched cases (24%), 14 pertained to asymptomatic patients. CONCLUSION: The ACR appropriateness criteria could be applied to 76% of the imaging procedure requests that we received from a general internal medicine clinic. These results suggest that the ACR appropriateness criteria can be applied to diagnostic imaging in a general ambulatory-care setting.

Adult↗
PubMed1998

An Internet-based ontology editor for medical appropriateness criteria.

Appropriateness criteria and practice guidelines seek to promote the cost-effectiveness use of medical interventions, and can be most useful when integrated with computer-based patient records and order-entry systems. Building an abstract model (ontology) of appropriateness criteria can require considerable effort among investigators at geographically dispersed institutions. To facilitate the construction and maintenance of ontologies for clinical appropriateness criteria, the author developed an Internet-based system for viewing and editing the knowledge model. The system, called NEON (Network-based Editor for ONtologies), uses the World Wide Web as a platform-independent user interface. NEON allows users to edit the indexing terms and the semantic network that form the ontology for a set of appropriateness criteria. Ontologies built using the system can be imported and exported using an open, internationally standardized format based on the Standard Generalized Markup Language (SGML).

Artificial Intelligence↗
PubMed1998

A multipurpose model of radiology appropriateness criteria.

RATIONALE AND OBJECTIVES: Appropriateness criteria and practice guidelines are being developed in attempts to improve the cost-effectiveness of medical care. The authors sought to make a set of radiology appropriateness criteria usable for education, computer-based decision support, and utilization review. MODEL DEVELOPMENT: Sixty clinical conditions from the American College of Radiology's appropriateness criteria were selected. To make the information more suitable for automation, the names of the imaging procedures were standardized. Indexing terms were assigned to identify clinical conditions and to distinguish between each condition's variants. Semantic relationships between terms were defined. Information about the clinical conditions and variants, radiologic procedures, indexing terms, and relationships was encoded into a standardized language for document interchange. IMPLEMENTATION: The 1,956 rows in the appropriateness criteria tables for the 60 clinical conditions and their 212 variants were mapped into references to 163 distinct imaging procedures. The system's knowledge base included 301 indexing terms and 569 additional terms. CONCLUSION: Radiology appropriateness criteria can be indexed and encoded into a form that facilitates their use and interchange. The use of open, internationally accepted standards is an important step to make such knowledge portable and suitable for integration with evolving computer-based patient record systems.

Computing Methodologies↗
PubMed1998

Self-documenting structured reports using open information standards.

Structured reporting systems use standardized data elements and predetermined data-entry formats to record observations. This article describes a system for structured data entry and reporting that generates reports encoded in the Standard Generalized Markup Language (SGML), an open, internationally accepted standard for document interchange. The structured report is self-documenting: it includes a definition of its allowable data field and values encoded as a report-specific SGML document type definition (DTD). By linking its reporting concepts with those of external vocabularies such as the UMLS Metathesaurus, this system can create open, universally comprehensible structured reports.

Data Display↗
PubMed1998

Extensible markup language (XML) in health care: integration of structured reporting and decision support.

The Extensible Markup Language (XML) is a newly adopted Internet protocol for data interchange designed to bring the key features of the Standard Generalized Markup Language (SGML; ISO 8879:1986)--extensibility, complex structures, and validation--to the World Wide Web. In this paper, we describe an architecture that uses XML to mediate between disparate client-server systems for structured reporting and decision support.

Bayes Theorem↗
PubMed1997

Construction of a Bayesian network for mammographic diagnosis of breast cancer.

Bayesian networks use the techniques of probability theory to reason under uncertainty, and have become an important formalism for medical decision support systems. We describe the development and validation of a Bayesian network (MammoNet) to assist in mammographic diagnosis of breast cancer. MammoNet integrates five patient-history features, two physical findings, and 15 mammographic features extracted by experienced radiologists to determine the probability of malignancy. We outline the methods and issues in the system's design, implementation, and evaluation. Bayesian networks provide a potentially useful tool for mammographic decision support.

Bayes Theorem↗
PubMed1997

BANTER: a Bayesian network tutoring shell.

We present an educational tool for bringing the information contained in a Bayesian network to the end user in an easily intelligible form. The BANTER shell is designed to tutor users in evaluation of hypotheses and selection of optimal diagnostic procedures. BANTER can be used with any Bayesian network containing nodes that can be classified into hypotheses, observations, and diagnostic procedures. The system enables one to present various types of queries to the network, to test one's ability to select optimal diagnostic procedures, and the request explanations. We describe the system's capabilities by illustrating how it functions with two structurally different network models of real-world medical problems.

Adult↗
PubMed1997

Appropriateness of imaging procedure requests: do radiologists agree?

OBJECTIVE: We explored the agreement among radiologists in their evaluation of the appropriateness of individual requests for imaging procedures. MATERIALS AND METHODS: We reviewed 318 noninterventional CT, sonographic, MR imaging, and nuclear medicine procedures ordered at a general internal medicine clinic during 8 months in 1995. Five subspecialty radiologists used data from the radiology request from and clinic notes to independently rate the appropriateness of each requested imaging procedure on a four-point scale. The radiologists were unaware of the results achieved by each procedure. Each case was reviewed by at least three radiologists, of whom at least one had relevant subspecialty expertise. Agreement among radiologists was analyzed using Cohen's kappa statistic and weighted kappa statistics and Cronbach's alpha statistic. RESULTS: Nonchance agreement (kappa) was .19 +/- .05; weighted kappa was .24 +/- .05. Interrater agreement was significantly greater than that expected from chance alone (p < .01). The composite score, defined as the average of the radiologists' scores for each case, showed moderate reliability, as evidenced by a value for Cronbach's alpha of 70. CONCLUSION: In the absence of explicit criteria, we found modest but statistically significant agreement among radiologists about the appropriateness of individual requests for imaging procedures. The disagreement among radiologists highlights the importance of developing well-reasoned, explicit criteria by which to judge the appropriateness of diagnostic radiology procedures. Further study is needed to elucidate the relationship between appropriateness and actual patient outcomes.

Adult↗
PubMed1997

A generalized language for platform-independent structured reporting.

Structured reporting systems allow health-care workers to record observations using predetermined data elements and formats. The author developed the Data-entry and Reporting Markup Language (DRML) to provide a generalized representational language for describing concepts to be included in structured reporting applications. DRML is based on the Standard Generalized Markup Language (SGML), an internationally accepted standard for document interchange. The use of DRML is demonstrated with the SPIDER system, which uses public-domain internet technology for structured data entry and reporting. SPIDER uses DRML documents to create structured data-entry forms, outline-format textual reports, and datasets for analysis of aggregate results. Applications of DRML include its use in radiology results reporting and a health status questionnaire. DRML allows system designers to create a wide variety of clinical reporting applications and survey instruments, and helps overcome some of the limitations seen in earlier structured reporting systems.

Forms and Records Control↗
PubMed1996

Positive predictive value of clinical suspicion for abdominal aortic aneurysm. Implications for use of ultrasonography.

To measure the positive predictive value (PPV) of clinical suspicion of abdominal aortic aneurysm (AAA), as confirmed by ultrasonography, we reviewed the records of 343 patients at a university medical center referred to ultrasonography for newly suspected AAA. Positive predictive value was 11.1% for large aneurysms of at least 5.0 cm and 18.7% for aneurysms of at least 3.5 cm, and was higher for men and older patients. For patients under 50 years of age, PPV was only 2.6%. Ultrasonography for clinically suspected AAA has a low positive predictive yield, particularly for men under age 50 and for women.

Adult↗
PubMed1996

Structured entry of radiology reports using World Wide Web technology.

Structured data entry--in which information is entered by using predetermined data elements and formats--has the potential to improve the radiology reporting process. The dependence on particular computer hardware and software platforms has posed a barrier to wider use of this approach. The World Wide Web (WWW), a client-server protocol for delivery of multimedia data via the Internet, was used to achieve platform-independent structured entry of radiology reports. A developmental system for structured entry of radiology reports, called SPIDER, incorporates a knowledge base of hierarchically organized concepts, a WWW server, and two specialized programs. The WebForm program transforms the system's knowledge into graphical WWW data-entry forms; the WebReport program converts data entered on these forms into outline-format reports. SPIDER received favorable evaluations from sonographers and physicians who used the system to record the results of several test cases. WWW technology can be used to achieve platform-independent entry of the results of radiologic procedures.

Artificial Intelligence↗
PubMed1996

Knowing the score: using predictive scoring systems in clinical practice.

Outcome scores have been promoted as adjuncts to clinical decision making, especially when further care is thought to be futile. The Pediatric Risk of Mortality score is used to calculate the risk of mortality for patients admitted to pediatric intensive care units. In this article the Pediatric Risk of Mortality score in evaluated for its ability to contribute to individual patient care decisions in the context of clinical practice. Through analysis several features of the Pediatric Risk of Mortality score were identified that require discretion if the score is to be used in decisions involving individual patients. These features include variability and bias introduced in data collection and data presentation. Also, outcome scores do not allow for the incorporation of patient and family values into the decision process. Outcome scores can provide some adjunctive information to clinicians, but they should be used with caution when making patient care decisions. Use of Pediatric Risk of Mortality scores in clinical practice must be tempered with a knowledge of the limitations of the scores, individual patient variability, the conditions under which the scores have been validated and collected and, most importantly, an awareness that outcome scores do not take into account the caregiver and patient values that are inherent in any treatment decision.

Child↗
PubMed1996

Decision aids in radiology.

Computer systems can help radiologists decide which tests to perform and which diagnoses to consider. Repositories of clinical data and general medical knowledge can provide information on demand for decision-making tasks; many of these information resources are available remotely via the Internet. Decision support systems can incorporate the techniques of artificial intelligence to apply their general knowledge to the features of a particular patient. Successful use of these technologies requires careful attention to design, implementation, and rigorous evaluation. Computer-based decision aids can improve the cost effectiveness and diagnostic accuracy of radiologic practice and are poised to play an important role in the future of radiology.

Decision Support Techniques↗
PubMed1996

Health status assessment via the World Wide Web.

We explored the use of the World Wide Web to collect health status information for medical outcomes research. The RAND 36-Item Health Survey 1.0 (RAND-36), which contains the 36 multiple-choice questions of the Medical Outcomes Study SF-36 "Short Form" and differs only in its simplified scoring scheme, was made available for anonymous use on the Internet. Participation in the survey was invited through health-related Internet news groups and mailing lists. Participants entered data and received, their scores using the World Wide Web protocol. Entries were recorded from 15 June 1995 to 14 June 1996 (1 year). The survey was completed anonymously by 4876 individuals with access to the World Wide Web. Two-thirds completed the survey within 5 minutes, and 97% did so within 10 minutes. The item-completion rate was 99.28%. Values of Cronbach's alpha of 0.76 to 0.90 for the scoring scales matched the high reliability found in the Medical Outcomes Study. The World Wide Web provides a method of rapidly measuring individual health status and may play an important role in advancing health services research and outcomes-based patient care.

Computer Communication Networks↗
PubMed1996

Knowledge representation for platform-independent structured reporting.

Structured reporting systems allow health care providers to record observations using predetermined data elements and formats. We present a generalized language, based on the Standard Generalized Markup Language (SGML), for platform-independent structured reporting. DRML (Data-entry and Report Markup Language) specifies hierarchically organized concepts to be included in data-entry forms and reports. DRML documents serve as the knowledge base for SPIDER, a reporting system that uses the World Wide Web as its data-entry medium. SPIDER generates platform-independent documents that incorporate familiar data-entry objects such as text windows, checkboxes, and radio buttons. From the data entered on these forms, SPIDER uses its knowledge base to generate outline-format textual reports, and creates datasets for analysis of aggregate results. DRML allows knowledge engineers to design a wide variety of clinical reports and survey instruments.

Computer Communication Networks↗