PubMed Health⌕ Search

Biomedical subjects

J K Vries

Publications and source records attributed to J K Vries.

At least 19 recordsLinked to original sources
PubMed1998

Using computer modeling to help identify patient subgroups in clinical data repositories.

OBJECTIVE: The ability to accurately and efficiently identify patient cases of interest in a hospital information system has many important clinical, research, educational and administrative uses. The identification of cases of interest sometimes can be difficult. This paper describes a two-stage method for searching for cases of interest. DESIGN: First, a Boolean search is performed using coded database variables. The user classifies the retrieved cases as being of interest or not. Second, based on the user-classified cases, a computer model of the patient cases of interest is constructed. The model is then used to help locate additional cases. These cases provide an augmented training set for constructing a new computer model of the cases of interest. This cycle of modeling and user classification continues until halted by the user. MEASUREMENTS: This paper describes a pilot study in which this method is used to identify the records of patients who have venous thrombosis. RESULTS: The results indicate that computer modeling enhances the identification of patient cases of interest.

Bayes Theorem↗
PubMed1997

Clinical event monitoring at the University of Pittsburgh.

Although the literature on event monitoring is extensive, it does not cover all issues that we encountered while developing an event monitor at our institution. We had to resolve issues related to event detection, scalability, what topics were suitable for asynchronous decision support, and overlap of efforts of other groups at the institution attempting to improve quality and lower cost of care. In this paper, we describe our experience deploying CLEM, the clinical event monitor at the University of Pittsburgh with emphasis on these topics.

Academic Medical Centers↗
PubMed1995

Linear intracerebral calcification after depth electrode implantation.

We report linear calcifications along the trajectories of previously implanted depth electrodes in 2 patients. A 20-year-old man and a 38-year-old woman with medically intractable complex partial seizures (CPS), underwent bilateral frontal and mesiotemporal depth electrode implantation as part of their epilepsy surgery workup. Brain computed tomography (CT) at that time was normal (except for cerebrellar atrophy in one case). One patient had a left anterotemporal lobectomy (ATL), and the other declined operation. Subsequent CT scans showed linear calcifications 1-2 cm long in the occipital lobes (unilateral in 1 and bilateral in the other) that followed the trajectories of the temporal depth electrodes. This finding remained unchanged at latest follow-up (2-2.5 years), and no new pathology has appeared on subsequent scans. No abnormalities of calcium metabolism were detected. Review of all available CT scans of our patients with a history of previous depth electrode implantation showed no additional similar cases. We believe this is the first report of intracerebral calcifications after depth electrode implantation.

Adult↗
PubMed1995

Building a medical multimedia database system to integrate clinical information: an application of high-performance computing and communications technology.

The rapid growth of diagnostic-imaging technologies over the past two decades has dramatically increased the amount of nontextual data generated in clinical medicine. The architecture of traditional, text-oriented, clinical information systems has made the integration of digitized clinical images with the patient record problematic. Systems for the classification, retrieval, and integration of clinical images are in their infancy. Recent advances in high-performance computing, imaging, and networking technology now make it technologically and economically feasible to develop an integrated, multimedia, electronic patient record. As part of The National Library of Medicine's Biomedical Applications of High-Performance Computing and Communications program, we plan to develop Image Engine, a prototype microcomputer-based system for the storage, retrieval, integration, and sharing of a wide range of clinically important digital images. Images stored in the Image Engine database will be indexed and organized using the Unified Medical Language System Metathesaurus and will be dynamically linked to data in a text-based, clinical information system. We will evaluate Image Engine by initially implementing it in three clinical domains (oncology, gastroenterology, and clinical pathology) at the University of Pittsburgh Medical Center.

Abstracting and Indexing↗
PubMed1995

Using agent-based technology to create a cost effective, integrated, multimedia view of the electronic medical record.

Image Engine is multi-user, client-server database for the storage, retrieval and sharing of a wide range of digitized biomedical images under development at the University of Pittsburgh. This paper provides an overview of the system and describes the use of agent-based technology to integrate clinical information from the Image Engine database and the MARS clinical information system at the University of Pittsburgh Medical Center. Agent-mediated links provide a mechanism for combining clinical data from multiple databases to create a unified, multimedia view of the electronic medical record.

Computer Communication Networks↗
PubMed1995

Image engine: an integrated multimedia clinical information system.

Image Engine is a microcomputer-based system for the integration, storage, retrieval, and sharing of digitized clinical images. The system seeks to address the problem of integrating a wide range of clinically important images with the text-based electronic patient record. Rather than create a single, integrated database system for all clinical data, we are developing a separate image database system that creates real-time, dynamic links to other network-based clinical databases. To the user, this system will present an integrated multimedia representation of the patient record, providing access to both the image and text-based data required for effective clinical decision making.

Abstracting and Indexing↗
PubMed1992

An automated indexing system utilizing semantic net expansion.

Automated subject indexing and the coordination of indexing with natural language search interfaces could provide solutions to some of the information retrieval problems facing the medical field today. This paper describes the construction of such an interface using semantic net expansion and a clinical neuroscience thesaurus, which provided a specialized vocabulary for use in both automated indexing of MEDLINE articles and an "intelligent" front-end for database searching. Though reviewed by a domain expert, the thesaurus was successfully built by nonexperts utilizing a set of rules. We report on testing thesaurus content and semantic net accuracy using a database of selected MEDLINE article abstracts.

Abstracting and Indexing↗
PubMed1992

CHARTLINE: providing bibliographic references relevant to patient charts using the UMLS Metathesaurus Knowledge Sources.

A successful medical informatics program helps its users to match their information needs as closely and efficiently as possible to the capabilities of the system. CHARTLINE is a computer program whose input is a free text, "natural language" patient chart in ASCII format. Using the UMLS Metathesaurus Knowledge Sources, CHARTLINE can suggest bibliographic references relevant to the patient case described in the chart. The program does not attempt to "understand" the natural language content of the chart. CHARTLINE only recognizes UMLS Metathesaurus Main Concept terms (or their synonyms) as they occur in the medical text, since those terms represent the tokens used to index the literature. The program depends on user feedback to determine which topics of a large number of potentially relevant subjects are of interest to the user.

Diagnosis, Computer-Assisted↗
PubMed1987

Malignant fibrous histiocytoma of the clivus: case report.

A case of malignant fibrous histiocytoma of the clivus in a 2 1/2-year-old boy is reported. There are no prior reports of this tumor in this location. The child was treated with operation, radiation therapy, and chemotherapy. The tumor recurred locally 21 months later. The recurrence was palliated by operation and chemotherapy, permitting an additional 20-month survival.

Child, Preschool↗
PubMed1985

Early detection of brainstem glioma using brainstem auditory evoked potentials.

Brainstem tumor was suspected in an 11-year-old boy presenting with a painless lateral rectus palsy, on the basis of abnormal brainstem auditory evoked potentials (BAEP), despite normal computed tomographic studies, the diagnosis being confirmed by biopsy. The BAEP improved after radiation therapy, but their later deterioration heralded the onset of recurrence two weeks before any adverse clinical symptoms appeared. The value of BAEP studies in the early detection of brainstem lesions and in monitoring their progress, is discussed.

Astrocytoma↗
PubMed1984

Visual evoked potentials in hydrocephalus: relationship to head size, shunting, and mental development.

Flash-evoked visual cortical potentials were measured in 54 infants and children with symptomatic hydrocephalus; 54 shunted, asymptomatic infants and children; and 57 controls. All patients were evaluated for head size, mental development, and history of infection of the nervous system. Hydrocephalic infants up to 60 weeks of conceptional age showed significant changes in the maturation curve of the latency to the main positive peak P2 (P100), particularly when their hydrocephalus was associated with an enlarged head or with infection. Older children of normal mental development presenting with acute hydrocephalus of recent onset had normal latencies to P2. Some persistent ventriculomegaly after shunting was also compatible with normal visual evoked potentials (VEPs). After shunting, the latency to P2 became normal in most of the patients who showed normal mental development, whereas retarded hydrocephalic children of all ages continued to have abnormal VEPs.

Cerebrospinal Fluid Shunts↗
PubMed1983

Stereotactic implantation of deep brain electrodes using computed tomography.

The selection of intracranial targets for stereotactic functional neurosurgical procedures traditionally has relied on information derived from pooled brain atlases and supplemented by contrast encephalographic or angiographic data from the individual patient. The integration of stereotaxy with computed tomography (CT) has permitted direct identification of intracranial targets based on multiplanar reformatted CT images from each individual patient. Four patients underwent the CT stereotactic implantation of a single deep brain electrode for the control of chronic pain (two cases) or of multiple depth electrodes for long term electroencephalographic recordings in the management of seizure disorders (two cases). In all patients, accurate and precise electrode placement was achieved from CT images alone. The use of CT permitted detailed anatomical stereotactic study of each patient's brain, the preplotting of electrode trajectories before probe insertion, and the rapid confirmation of precise electrode placement. Intraoperative contrast encephalography was not necessary. Functional neurosurgery was performed successfully and advantageously using CT stereotactic technique alone.

Adult↗
PubMed1983

Unilateral hydrocephalus secondary to congenital atresia of the foramen of Monro. Case report.

Unilateral hydrocephalus is an uncommon entity which results from obstruction at the level of the foramen of Monro. It is usually brought about by tumors or inflammatory conditions. Congenital maldevelopment of the foramen of Monro is an often postulated, yet never proven, cause of unilateral ventricular enlargement. A case of unilateral hydrocephalus secondary to congenital atresia of the foramen of Monro is presented to document the occurrence of this condition.

Cerebral Ventricles↗
PubMed1983

Nonsurgical management of extradural hematomas in children.

With the advent of computerized tomography (CT), an increasing number of patients with only minimal neurological symptoms and no signs of brain herniation are found to harbor subacute or chronic extradural hematomas (EH's). The authors present the cases of 11 symptomatic but neurologically normal children with medium to large EH's managed by close observation. These EH's were discovered 4 hours to 6 days after injury; three were in the posterior fossa, seven over the frontoparietal convexity, and one in the temporal fossa. These clots were followed by serial CT scans. Nine children recovered without surgery from 4 to 18 days after injury, and all had evidence on CT of spontaneous clot resorption. Of these nine EH's, five clots displayed volume expansion from 5 to 16 days after injury before final resorption occurred. Expansion correlated with persistence or increase in symptoms, whereas resorption correlated with improvement. Two patients showed gradual uncal herniation on Days 6 and 8, respectively, presumably during the "expansile phase" of their clots. Both had emergency craniotomy and recovered without morbidity. It is hypothesized that the resorption dynamics of the subacute or chronic EH are similar to that of the chronic subdural hematoma, with predictable volume changes, and the outcome of each lesion depends on the interplay between the patient's intracranial pressure buffering capacity and the rate of volume change. If subtle signs of brain dysfunction are adopted to signal the failure of conservative treatment and the need for craniotomy, these patients may be safely, and many successfully, managed without surgery. Factors that influence outcome of medical treatment include the size, location, configuration, and the rapidity of accumulation of the clot, the presence of associated intradural lesions, the extracranial decompression of blood through skull diastases, and the age of the patient. These factors, the criteria for patient selection, and the indications for immediate operative intervention are discussed.

Adolescent↗