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PubMed1988

An efficient method for smoothing indicator-dilution and other unimodal curves.

A mathematical function has been developed for approximating unimodal functions, particularly those which are non-Gaussian, skewed, and incomplete. It is useful as an alternative to cubic splines in smoothing noisy experimental data. Particular applications are to indicator-dilution curves and probability density functions of varied form. In its Fortran implementation, SMOEX, it is computationally inexpensive compared to standard cubic spline smoothing routines and requires less storage to preserve the smoothed function for retrieval or interpolation.

Animals↗
PubMed2003

Local electronic storage of radiological studies for radiosurgery.

OBJECTIVE: Although radiosurgical practice mandates meticulous radiological follow-up, even the most efficient radiology department can be overwhelmed by the large number of radiosurgical patients who have undergone diagnostic studies for many years at many different institutions to follow many separate lesions. Although the task of assembling these studies is theoretically possible, because they are spread out in time and space, it is often impractical. We therefore sought to construct a computer-based system that could store images from multiple sources and present them instantly for review. METHODS: We attached a flatbed film scanner to a standard desktop computer in our clinic and scanned selected sheets of film into an image database at each visit of a radiosurgical patient. "Low-tech" solutions were deliberately chosen-that is, to enhance ease and software compatibility, we used the operating system's directory structure for organization of data instead of proprietary software. Standard commercially available software was used to review studies that had been previously scanned. RESULTS: During a 2- to 3-year period, images were scanned from 1129 studies performed on 435 patients. Images could be reviewed instantly and compared with current studies, and scanning a single piece of film required approximately 30 seconds. We estimate that the current capacity of our computer memory will satisfy our needs for approximately 12 years. CONCLUSION: Assembly of an efficient and inexpensive system for image storage and retrieval suitable for radiosurgical practice is feasible and straightforward. Although our system is not a substitute for a radiology department, it obviates the constant frustration of "finding the films" and has become an essential part of our radiosurgical practice.

Brain Diseases↗
PubMed1998

Recommendations for image prefetch or film digitization strategy based on an analysis of an historic radiology image database.

Picture archiving and communications systems (PACS) utilize short- and long-term storage to provide both rapid retrieval and large storage capacity. Owing to the practical limitations imposed on the size of the much faster short-term storage, it is important to use an effective algorithm in the retrieval of comparison images from long to short-term storage. A strategy must be used to maximize the likelihood that the relevant historic images have been previously retrieved into short-term memory. Data were collected with a database consisting of 754 consecutive examinations and 7,723 associated historic studies. The most frequent number of previous examinations was zero (11% of patients). In 45% of cases, no previous matching examinations had been performed. Two basic strategies of image retrieval were evaluated. The first algorithm retrieved the last n studies in chronological order. The second strategy tested was retrieval based on a defined interval of time. This strategy was found to be less efficient. By using the former strategy, a 91% success rate (defined as successful retrieval of the previous matching exam) was achieved with retrieval of only 30% of the prior exams. The second approach required retrieval of 70% of the prior exams to achieve a 90% success rate for the previous matching exam. However, the data from this latter strategy suggest that examinations are often ordered in clusters. Thus, there was found to be a 72% likelihood that a previous matching exam, if present, would available on a PACS after only 1 week of operation, and an 80% chance after only 1 month of operation. The data therefore suggest that digitization of film in a new PACS environment might not be necessary owing to the relatively short period of time required to populate the database with historical studies.

Algorithms↗
PubMed2006

Comprehensive processing, display and analysis for in vivo MR spectroscopic imaging.

Image reconstruction for magnetic resonance spectroscopic imaging (MRSI) requires specialized spatial and spectral data processing methods and benefits from the use of several sources of prior information that are not commonly available, including MRI-derived tissue segmentation, morphological analysis and spectral characteristics of the observed metabolites. In addition, incorporating information obtained from MRI data can enhance the display of low-resolution metabolite images and multiparametric and regional statistical analysis methods can improve detection of altered metabolite distributions. As a result, full MRSI processing and analysis can involve multiple processing steps and several different data types. In this paper, a processing environment is described that integrates and automates these data processing and analysis functions for imaging of proton metabolite distributions in the normal human brain. The capabilities include normalization of metabolite signal intensities and transformation into a common spatial reference frame, thereby allowing the formation of a database of MR-measured human metabolite values as a function of acquisition, spatial and subject parameters. This development is carried out under the MIDAS project (Metabolite Imaging and Data Analysis System), which provides an integrated set of MRI and MRSI processing functions. It is anticipated that further development and distribution of these capabilities will facilitate more widespread use of MRSI for diagnostic imaging, encourage the development of standardized MRSI acquisition, processing and analysis methods and enable improved mapping of metabolite distributions in the human brain.

Algorithms↗
PubMed1994

Recognition of related proteins by iterative template refinement (ITR).

Predicting the structural fold of a protein is an important and challenging problem. Available computer programs for determining whether a protein sequence is compatible with a known 3-dimensional structure fall into 2 categories: (1) structure-based methods, in which structural features such as local conformation and solvent accessibility are encoded in a template, and (2) sequence-based methods, in which aligned sequences of a set of related proteins are encoded in a template. In both cases, the programs use a static template based on a predetermined set of proteins. Here, we describe a computer-based method, called iterative template refinement (ITR), that uses templates combining structure-based and sequence-based information and employs an iterative search procedure to detect related proteins and sequentially add them to the templates. Starting from a single protein of known structure, ITR performs sequential cycles of database search to construct an expanding tree of templates with the aim of identifying subtle relationships among proteins. Evaluating the performance of ITR on 6 proteins, we found that the method automatically identified a variety of subtle structural similarities to other proteins. For example, the method identified structural similarity between arabinose-binding protein and phosphofructokinase, a relationship that has not been widely recognized.

Amino Acid Sequence↗
PubMed1985

Microcomputer applications in pathology research.

In a study of over 700 cases of uveal melanoma on file in the Department of Pathology of Wills Eye Hospital, a low-cost microcomputer using commercially available software (without modification) was used to: word process and edit this manuscript, create a patient file storage and retrieval system including the ability to create subfiles, merge files, and interchange file types, plot data points in several different graphic formats, transcribe and store information from microscopic tissue sections containing intraocular melanomas, and solve complex equations including statistical analysis. The results showed that over 150 different ophthalmologists contributed specimens to this data base. The mean age of the patients studied was 57 years and the tumors were evenly distributed according to sex and laterality of the eye. This study illustrates the feasibility of using a low-cost microcomputer and commercially available software in the study of a large patient data base.

Computers↗
PubMed1994

Data compression by linear prediction for storage and transmission of EEG signals.

The EEG time series has been subjected to various formalisms of analysis to extract meaningful information regarding the underlying neural events. In this paper the linear prediction (LP) method has been used for analysis and presentation of spectral array data for the better visualisation of background EEG activity. It has also been used for signal generation, efficient data storage and transmission of EEG. The LP method is compared with the standard Fourier method of compressed spectral array (CSA) of the multichannel EEG data. The autocorrelation autoregressive (AR) technique is used for obtaining the LP coefficients with a model order of 15. While the Fourier method reduces the data only by half, the LP method just requires the storage of signal variance and LP coefficients. The signal generated using white Gaussian noise as the input to the LP filter has a high correlation coefficient of 0.97 with that of original signal, thus making LP as a useful tool for storage and transmission of EEG. The biological significance of Fourier method and the LP method in respect to the microstructure of neuronal events in the generation of EEG is discussed.

Algorithms↗
PubMed1992

Identification of fractures from computerized Medicare files.

Study of non-hip fractures, which are a serious public health problem for persons greater than or equal to 65 years of age, has been hindered by the absence of an economical method for case identification. We assessed the utility of computerized Medicare inpatient, emergency room, hospital outpatient department and physician claims for identifying fractures in an elderly Tennessee Medicaid population. We used these files for 1987 to identify 3086 possible fractures and reviewed medical records for a sample of 1440. Using this sample, we developed a definition of probable fractures that excluded claims unlikely to represent newly diagnosed fractures. For all fractures, this definition had a positive predictive value of 94%, which for individual fracture sites, ranged from 79% (tibia/fibula) to 98% (hip). Of fractures in the reviewed sample, 91% were identified as probable fractures; this upper bound for sensitivity varied between 75% (femoral shaft) and 100% (patella). These data suggest that computerized Medicare files can be used for rapid and economical fracture ascertainment among persons greater than or equal to 65 years of age. However, further work is needed to obtain better estimates of sensitivity.

Aged↗
PubMedDate not supplied

Preliminary time-flow study: comparison of interpretation times between PACS workstations and films.

Toshiba Hospital installed a PACS and RIS in the diagnostic imaging department along with a hospital-wide HIS in May 1993. Our PACS includes three diagnostic workstations each of which is provided with six monochrome CRT monitors. The diagnostic workstations have been used as the primary tools for interpretation of almost all radiographic images. The actual image interpretation time was measured for diagnostic workstations (237 examinations) and for conventional hard-copy films (219 examinations) for CR, CT, and MRI. The difference in interpretation times between diagnostic workstations and films was not significant. With regard to image interpretation time, diagnostic workstations are thought to be acceptable for practical image reading.

Computer Systems↗
PubMed2004

Using CISMeF MeSH "Encapsulated" terminology and a categorization algorithm for health resources.

INTRODUCTION: CISMeF is a Quality Controlled Health Gateway using a terminology based on the Medical Subject Headings (MeSH) thesaurus that displays medical specialties (metaterms) and the relationships existing between them and MeSH terms. OBJECTIVE: The need to classify the resources within the catalogue has led us to combine this type of semantic information with domain expert knowledge for health resources categorization purposes. MATERIAL AND METHODS: A two-step categorization process consisting of mapping resource keywords to CISMeF metaterms and ranking metaterms by decreasing coverage in the resource has been developed. We evaluate this algorithm on a random set of 123 resources extracted from the CISMeF catalogue. Our gold standard for this evaluation is the manual classification provided by a domain expert, viz. a librarian of the team. RESULTS: The CISMeF algorithm shows 81% precision and 93% recall, and 62% of the resources were assigned a "fully relevant" or "fairly relevant" categorization according to strict standards. DISCUSSION: A thorough analysis of the results has enabled us to find gaps in the knowledge modeling of the CISMeF terminology. The necessary adjustments having been made, the algorithm is currently used in CISMeF for resource categorization.

Abstracting and Indexing↗
PubMed2005

Influences, usage, and outcomes of Internet health information searching: multivariate results from the Pew surveys.

This paper provides results from seven major nationally representative datasets (two in detail) from the Pew Internet and American Life Project to answer two primary questions: (1) what influences people to seek online health information and (2) what influences their perceived outcomes from having access to this information? Cross-tabulations, logistic regressions, and multidimensional scaling are applied to these survey datasets. The strongest and most consistent influences on ever, or more frequently, using the Internet to search for health information were sex (female), employment (not fulltime), engaging in more other Internet activities, more specific health reasons (diagnosed with new health problem, ongoing medical condition, prescribed new medication or treatment), and helping another deal with health issues. Internet health seeking is consistently similar to general Internet activities such as email, news, weather, and sometimes hobbies. A variety of outcomes from or positive assessments of searching for Internet health information are predicted most strongly by sex (female), engaging in other Internet activities, Internet health information seeking including more frequent health seeking, more specific health reasons, belonging to an online support group sharing health interests, and helping another deal with an illness or major health condition.

Adolescent↗
PubMed2004

Measuring hospice care: the National Hospice and Palliative Care Organization National Hospice Data Set.

Hospice has seen rapid growth in recent years, but there is a lack of consistency among hospices when it comes to compliance with standards of care. Consequently, hospices vary in performance and in services they provide. With state hospice organizations, the NHPCO developed a National Data Set (NDS) intended to understand demographics, practices, and outcomes; illustrate industry effectiveness; facilitate communication of industry legislative needs; and to support agency performance and improvement. Our paper describes development of the NDS and data that are being collected, and summarizes key findings from the 2000, 2001, and 2002 NDS. The data collection process, which began in 1999, has evolved substantially over a 4-year period to the point that we believe the 2002 NDS represents a well-designed core that will receive only minor modifications annually. This database will be invaluable for comparative audit, clinical practice and managing services because only that which is measured can be improved.

Data Collection↗
PubMed2006

Electronic crossmatching.

The crossmatch (XM) is an important part of routine pretransfusion testing. It is used to detect ABO incompatibility and other clinically significant antibodies. The XM has been modified many times and, in recent years, has been abbreviated. The 2 common types of XM currently being done are the immediate spin XM for antibody-negative patients and the antiglobulin XM for the rest. The antiglobulin phase of the XM is generally considered optional, unless a clinically significant antibody is present. Originally, the XM was intended to be a final check for ABO compatibility and for the detection of unexpected antibodies. Electronic crossmatching was first introduced at the University of Michigan Medical Center in 1992. This paper summarizes the basic principles, current guidelines, regulatory requirements, and some recommendations that may prove useful for the implementation of electronic crossmatching.

ABO Blood-Group System↗
PubMed1998

Digital archival and exchange of events in a simple format for polygraphic recordings with application in event related potential studies.

This paper describes a simple method of event encoding as an extension to a previously defined standard format, the European Data Format (EDF). The specification ensures full backward compatibility with the existing definition. By using this extension, the format can be used to store both continuous recordings and selected epochs of recordings. The encoding is performed in a channel of event-codes or in a pseudo-channel for annotations. Standardisation of event encoding is discussed. Decoding of events or annotations from the extended format is implemented at the application level. Existing programs that do not support the new encoding scheme still operate correctly and can simply ignore the new channels in processing 'extended' data files. The event encoding is also compatible with EDF's capability to encode channels of different sampling frequency.

Data Interpretation, Statistical↗
PubMed2003

Evaluating the reliability and validity of three tools to assess the quality of health information on the Internet.

The quality of Internet information needs to be evaluated and several tools exist for this purpose. However, none have demonstrated reliability and validity. This study tested the internal consistency and validity of the information quality tool (IQT), quality scale (QS) and DISCERN using 89 web sites discussing smoking cessation. The inter-rater reliability of the tools was established by exploring the agreement between two independent raters for 22 (25%) of the sites. The IQT and DISCERN possessed satisfactory internal consistency (as measured by Cronbach's alpha). The IQT, QS and DISCERN showed satisfactory inter-rater reliability (as measured by kappa and intraclass correlations). The IQT, QS and DISCERN correlated positively with each other, supporting the convergent validity of the tools. This study provides some evidence for the reliability and validity of the IQT, QS and DISCERN, although this needs testing in further research with different types of Internet information and larger sample sizes.

Authorship↗