Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Computing Methodologies”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,333 records · Page 74Linked to original sources
PubMed2006

Medicaid program; state allotments for payment of Medicare Part B premiums for qualifying individuals: federal fiscal year 2006. Interim final rule with comment period.

This interim final rule with comment period sets forth the methodology and process used to compute and issue each State's allotment for fiscal year (FY) 2006 and FY 2007 that is available to pay Medicare Part B premiums for qualifying individuals. It also provides the preliminary FY 2006 allotments determined under this methodology.

Cost Sharing↗
PubMed2002

Using imprecise probabilities to address the questions of inference and decision in randomized clinical trials.

Randomized controlled clinical trials play an important role in the development of new medical therapies. There is, however, an ethical issue surrounding the use of randomized treatment allocation when the patient is suffering from a life threatening condition and requires immediate treatment. Such patients can only benefit from the treatment they actually receive and not from the alternative therapy, even if it ultimately proves to be superior. We discuss a novel new way to analyse data from such clinical trials based on the use of the recently developed theory of imprecise probabilities. This work draws an explicit distinction between the related but nevertheless distinct questions of inference and decision in clinical trials. The traditional question of scientific interest asks 'Which treatment offers the greater chance of success?' and is the primary reason for conducting the clinical trial. The question of decision concerns the welfare of the patients in the clinical trial, asking whether the accumulated evidence favours one treatment over the other to such an extent that the next patient should decline randomization and instead express a preference for one treatment. Consideration of the decision question within the framework of imprecise probabilities leads to a mathematical definition of equipoise and a method for governing the randomization protocol of a clinical trial. This paper describes in detail the protocol for the conduct of clinical trials based on this new method of analysis, which is illustrated in a retrospective analysis of data from a clinical trial comparing the anti-emetic drugs ondansetron and droperidol in the treatment of postoperative nausea and vomiting. The proposed methodology is compared quantitatively using computer simulation studies with conventional clinical trial designs and is shown to maintain high statistical power with reduced sample sizes, at the expense of a high type I error rate that we argue is irrelevant in some specific circumstances. Particular emphasis is placed on describing the type of medical conditions and treatment comparisons where the new methodology is expected to provide the greatest benefit.

Antiemetics↗
PubMed2006

Computer prediction of balloon angioplasty from artery imaging.

The success of angioplasty depends on a balance between two conflicting objectives: maximization of artery lumen patency and minimization of mechanical damage. A finite element model for the patient-specific prediction of angioplasty is proposed as a potential tool to assist clinicians. This paper describes the general methodology and the algorithm that computes device/artery friction work during balloon insertion and deployment. The potential of the model is demonstrated with examples that include artery model reconstruction and prediction of friction on the arterial wall during balloon insertion and deployment.

Algorithms↗
PubMed1996

Optima: a windows-based program for computer-aided optimization of controlled-release dosage forms.

The purpose of this work was to develop a computer program that assists optimization of controlled-release devices, both visually and mathematically, using response surface methodology (RSM). A Windows-based computer program, Optima, which interactively implemented a number of subroutines for the optimization procedure, was developed. Optima is an integrated, user-friendly, and graphically oriented program for pharmaceutical dosage form optimization. Central composite design is implemented in the program. First- and second-order models containing up to five variables can be fitted to the data. The user can also choose between linear and exponential individual desirability functions, and use them to construct an overall desirability function that combines all the response variables in a single response. The program can predict the optimum levels of experimental variables, with respect to individual responses and/or the overall desirability. Optima has been successfully used in the development of sustained-release AZT-loaded microspheres. During the optimization process, three experimental variables were investigated and four responses were measured. The experimental design was a central composite design that was generated by the program. The response values were used by the program to calculate the individual desirability functions, which were then combined into an overall desirability function. The individual responses as well as the overall desirability function were optimized by fitting to a second-order polynomial equation. The response surfaces were generated and optimum levels of the experimental variables were predicted. The observed responses of the optimized formulation were very close to those predicted by Optima. The program proved to be a very useful, integrated tool for optimization of the controlled-release microspheres.

Computer Graphics↗
PubMed1995

[Active computer systems for medical education: approach and implementation].

The methodological bases and ways of building and using the new type of the educational computer-aided systems for physicians, the Diagnostic trainer, are discussed in the paper. The user's work on the Diagnostic Trainer proceeds in the form of a game during which the system stimulates clinical cases while the user analyzes them. The Diagnostic Trainer uses its knowledge base for simulations and requires no clinical cases to be prepared beforehand. The Diagnostic Trainer never forces the user to do, but always fixes his/her attention on the available essential points and possible contradictions between the specific clinical case and the user's strategy to make a decision.

Computer-Assisted Instruction↗
PubMed2005

New methodologies for ligand-based virtual screening.

Computational screening of compound databases has become increasingly popular in pharmaceutical research. Virtual screening approaches can roughly be divided into target structure-based screening (often referred to as docking) and screening using active compounds as templates (ligand-based virtual screening). Ligand-based screening techniques essentially focus on comparative molecular similarity analysis of compounds with known and unknown activity, regardless of the methods or algorithms used. In this review, we first provide an overview of widely used ligand-based virtual screening approaches including various database filters and then discuss recent trends in this field and new methodological developments.

Database Management Systems↗
PubMed2005

Modeling of porous filter penneability via image-based stochastic reconstruction of spatial porosity correlations.

A methodology for producing a pore-scale, 3D computational model of porous filter permeability is developed that is based on the analysis of 2D images of the filter matrix and first principles. The computationally reconstructed porous filter model retains statistical details of porosity and the spatial correlations of porosity within the filter and can be used to calculate permeability for either isotropic or 1D anisotropic porous filters. In the isotropic case, validation of the methodology was conducted using 0.2 and 0.8 microm ceramic membrane filters,forwhich it is shown that the image-based computational models provide a viable statistical reproduction of actual porosity characteristics. It is also shown that these models can predict water flux directly from first principles with deviations from experimental measurements in the range of experimental error. In the anisotropic case, validation of the methodology was conducted using a natural river sand filter. For this case, it is shown that the methodology yields predictions of filtration velocity that are similar or better than predictions offered by existing filtration models. It was found for the sand filter that the deviation between observation and prediction was mostly due to swelling during the preparation of the sand filter for imaging and can be reduced significantly using alternative methods reported in the literature. On the basis of these results, it is concluded that the computational reconstruction methodology is valid for porous filter modeling, and given that it captures pore-scale details, it has potential application to the investigation of permeability decline underthe influence of pore-scale fouling mechanisms.

Engineering↗
PubMedDate not supplied

PathMaster: content-based cell image retrieval using automated feature extraction.

OBJECTIVE: Currently, when cytopathology images are archived, they are typically stored with a limited text-based description of their content. Such a description inherently fails to quantify the properties of an image and refers to an extremely small fraction of its information content. This paper describes a method for automatically indexing images of individual cells and their associated diagnoses by computationally derived cell descriptors. This methodology may serve to better index data contained in digital image databases, thereby enabling cytologists and pathologists to cross-reference cells of unknown etiology or nature. DESIGN: The indexing method, implemented in a program called PathMaster, uses a series of computer-based feature extraction routines. Descriptors of individual cell characteristics generated by these routines are employed as indexes of cell morphology, texture, color, and spatial orientation. MEASUREMENTS: The indexing fidelity of the program was tested after populating its database with images of 152 lymphocytes/lymphoma cells captured from lymph node touch preparations stained with hematoxylin and eosin. Images of "unknown" lymphoid cells, previously unprocessed, were then submitted for feature extraction and diagnostic cross-referencing analysis. RESULTS: PathMaster listed the correct diagnosis as its first differential in 94 percent of recognition trials. In the remaining 6 percent of trials, PathMaster listed the correct diagnosis within the first three "differentials." CONCLUSION: PathMaster is a pilot cell image indexing program/search engine that creates an indexed reference of images. Use of such a reference may provide assistance in the diagnostic/prognostic process by furnishing a prioritized list of possible identifications for a cell of uncertain etiology.

Abstracting and Indexing↗
PubMed1997

[Virtual simulation: means and methodology].

State of the art imaging and computer systems coupled with the development of superior visualisation and multiplane reconstruction software have opened new perspectives in treatment planning. "Virtual simulation" of the irradiation technique allows definition in 3D of the optimised geometrical characteristics of the treatment beams with respect to anatomical structures of the patient. One can then visualise the beam direction and target volume coverage in the "virtual patient", leading to very precise radiotherapy. However, this "three dimensional" approach requires not only technical means, but also a methodology and an appropriate system of quality assurance for each step of the treatment planning, as well as significant multidisciplinary input.

Computer Simulation↗
PubMed2006

Medicaid program; state allotments for payment of Medicare Part B premiums for qualifying individuals: federal fiscal year 2006 and fiscal year 2007. Final rule.

This final rule sets forth the methodology and process used to compute and issue each State's allotments for fiscal years (FY) 2006 and FY 2007 that are available to pay Medicare Part B premiums for qualifying individuals. It also provides the final FY 2006 allotments and the preliminary FY 2007 allotments determined under this methodology. We are also confirming the April 28, 2006 interim final rule as final.

Eligibility Determination↗
PubMedDate not supplied

Normal splenic volume in adults by computed tomography.

BACKGROUND/AIMS: The purpose of the present study was to examine variations in spleen size in adults. METHODOLOGY: The spleen volume was measured by computed tomography in 150 healthy donors for liver transplantation. The correlations between spleen volume and age, gender, body weight and body surface area were analyzed. RESULTS: The mean volume of the spleen was 112 cm3, ranging from 32 to 209 cm3. The spleen volume significantly correlated with age (R = 0.36, p = 0.0002), but not with body weight or surface area. Gender did not influence the variation in spleen size. CONCLUSIONS: A crude normal range stratified by age should provide useful information in the diagnosis of splenomegaly.

Adult↗
PubMed1991

Rat sperm motility analysis: methodologic considerations.

The objective of these studies was to optimize conditions for computer-assisted sperm analysis (CASA) of rat epididymal spermatozoa. Methodologic issues addressed include sample collection technique, sampling region within the epididymis, type of diluent medium used, and sample chamber depth. In addition, sources of variation were identified and accuracy of the analysis was examined. All samples in this report were analyzed using a Hamilton Thorn Motility Analyzer (HTM-2000; Hamilton Thorn Research, Danvers, MA). We found that allowing the sperm to swim out from cuts made in the distal cauda epididymidis yielded samples with percentages of motile sperm 60% higher than samples collected using an aspiration method. Furthermore, sperm isolated from the distal cauda epididymidis exhibited slightly but significantly greater percentages of motile sperm and swimming speeds than sperm isolated from the proximal cauda epididymidis. Of the four motility media examined, all maintained a high percentage of motile sperm over an hour-long incubation period, but Medium 199 and modified Hanks' Balanced Salt supported substantially greater sperm velocity than Dulbecco's Phosphate Buffered Saline (with Ca++ and Mg++), with or without glucose. Motility and velocity endpoints were comparable in 200-, 100-, or 40-micron deep chambers, but significantly lower in 20-micron-deep chambers. Since these and presumably other variables in the preparation and analysis of rat sperm do influence the assessed motility endpoints, it is important to standardize these methods and to consider these issues when interpreting CASA data.

Animals↗
PubMed1990

Reference standards for software evaluation.

The field of automated ECG analysis was one of the earliest topics in Medical Informatics and may be regarded as a model both for computer-assisted medical diagnosis and for evaluating medical diagnostic programs. The CSE project has set reference standards of two kinds: In a broad sense, a standard how to perform a comprehensive evaluation study, in a narrow sense, standards as specific references for evaluating computer ECG programs. The evaluation methodology used within the CSE project is described as a basis for presentation of results which are published elsewhere in this issue.

Diagnosis, Computer-Assisted↗
PubMed1983

Vestibular function testing: where are we in 1983?

Conceptual, technological, electronic and computer revolutions have transformed the methodology for evaluating the patient with dysequilibrium. What has been said and written for the past 25 years is not currently applicable. Present day, cost effective, clinical evaluation format is presented, including changes and deletions in the conventional ENG test battery. It also includes the addition of computer technology in the rotation and ocular tracking tests. These deletions and additions in technique provide the clinician with more useful practical data for diagnosis. There is also capability for patient follow-up and monitoring. These concepts are presented from the clinical vantage point and are supported with patient evaluation examples.

Caloric Tests↗
PubMed1996

Classification of astrocytomas and malignant astrocytomas by principal components analysis and a neural net.

The classification of astrocytomas, astrocytomas with anaplastic foci and glioblastoma multiformes is not always straightforward because the tumors form a histological continuum. The use of principal component analysis (PCA) and neural nets in the classification of these tumors is explored. PCA was performed on 14 histological features recorded from 52 gliomas classified by the Radiation Therapy Oncology Group method (17 astrocytomas, 18 astrocytomas with anaplastic foci, 17 glioblastoma multiformes). Four of the 14 possible 'scores' derived from this analysis were selected to summarize the histological variability seen in all the tumors. These scores were mostly significantly different between tumor types and were thus used to successfully train a neural net to correctly classify these tumors. The first principal component (score) supported the use of increasing cellularity, mitoses, endothelial proliferation, and necrosis in differentiating between the tumor categories, but accounted for only 39% of the variability seen. Other histological features that were significant components of the other scores included the presence of multinucleated or giant cells, gemistocytes, atypical mitoses and changes in nuclear chromatin. Computer programs derived from the methodology described provide a way of standardizing glioma diagnosis and may be extended to assist with management decisions.

Astrocytoma↗
PubMed1989

Forecasting systems in managing hospital services demand: a review of applicability and a measure of utility.

A comprehensive literature review of forecasting methodologies and their specific applications to managing hospital services demand provided a credible base for the ensuing study of current forecasting usage. A sample of 40 hospitals was analyzed to measure the current perceived urgency to utilize forecasting systems. These findings were then compared with perceived actual usage. The incidence of formal forecasting systems actually being utilized was lower than the perceived need to use such systems. Identification of principal methodologies utilized and an assessment of computer-assisted forecasting indicated that a strong reliance on qualitative, manually-derived methodologies still remains. Correlation analyses of key exogenous variables indicated that the larger sized hospitals utilized computerized methodologies and had the highest measures of perceived need for, and actual practice of, formal forecasting programs.

Evaluation Studies as Topic↗
PubMed1988

The National Boards of the future.

The National Board of Medical Examiners has decided to implement computer-based testing as the standard examination methodology for all students in the near future. The author describes how computer-based testing will eventually be used and the direction that the National Board Examinations will take in the future.

Clinical Competence↗