[The University of X-ray Laboratory Assistants. Lesson 4. Megabyte memories].
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Artifacts↗
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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.
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The next generation Internet and health care: a civics lesson for the informatics community.
The Internet provides one of the most compelling examples of the way in which government research investments can, in time, lead to innovations of broad social and economic impact. This paper reviews the history of the Internet's evolution, emphasizing in particular its relationship to medical informatics and to the nation's health-care system. Current national research programs are summarized and the need for more involvement by the informatics community and by federal health-care agencies is emphasized.
Computing Methodologies↗
The computer synthesis of expressive faces.
This paper presents a methodology for the computer synthesis of realistic faces capable of expressive articulations. A sophisticated three-dimensional model of the human face is developed that incorporates a physical model of facial tissue with an anatomical model of facial muscles. The tissue and muscle models are generic, in that their structures are independent of specific facial geometries. To synthesize specific faces, these models are automatically mapped onto geometrically accurate polygonal facial representations constructed by photogrammetry of stereo facial images or by non-uniform meshing of detailed facial topographies acquired by using range sensors. The methodology offers superior realism by utilizing physical modelling to emulate complex tissue deformations in response to coordinated facial muscle activity. To provide realistic muscle actions to the face model, a performance driven animation technique is developed which estimates the dynamic contractions of a performer's facial muscles from video imagery.
Computer Graphics↗
A pilot study of a computer-assisted cell-phone interview (CACI) methodology to survey respondents in households without telephones about alcohol use.
An intrinsic drawback with the use of a computer-assisted telephone interview (CATI) survey methodology is that people who live in households without a connected landline telephone are excluded from the survey sample. This paper presents a pilot of the feasibility of a computer-assisted cell-phone interview (CACI) methodology designed to survey people living in households without a telephone about alcohol use and be compatible with a larger telephone based alcohol sample. The CACI method was found to be an efficient and cost competitive method to reach non-telephone households. Telephone ownership was found to make a difference to the typical occasion amount of alcohol consumed, with respondents from households without telephones drinking significantly more than those with telephones even when consumption levels were controlled for socio-economic status. Although high levels of telephone ownership in the general population mean these differences may not have any impact on population alcohol measures they may be important in sub-populations where telephone ownership is lower.
Adolescent↗
[The role of computers in modernizing concepts and diagnostic methodologies in acute pulp inflammation].
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Diagnosis, Computer-Assisted↗
[Use of computers for improving the activities of health facilities at industrial plants].
The organizational and methodological aspects of computer application at treatment facilities serving the industrial enterprises are described. Some conceptions of operating the automated centre of mass medical examinations at Novomoskovsk tube plant are outlined. A methodological approach is suggested: the use of computer systems according to the number of industrial workers. Considerable reserves of improving the performance of treatment facilities serving the workers and employees of industrial enterprises are pointed out.
Diagnosis, Computer-Assisted↗
An evaluation of population pharmacokinetics in therapeutic trials. Part I. Comparison of methodologies.
NONMEM, a computer program that uses the method of extended least-squares analysis, has been advocated as a means of obtaining estimates of population pharmacokinetic parameters when only fragmentary information can be obtained from subjects. To assess the performance of this program, we compared NONMEM with traditional methods for the estimation of population pharmacokinetic parameters with data collected during a phase III clinical trial of alprazolam. NONMEM estimates of the population mean clearance and its coefficient of variation were identical to the estimates obtained with traditional pharmacokinetic techniques. Moreover, NONMEM estimates of these parameters remained stable even when a few as three data points were available per subject. NONMEM estimates of the mean volume of distribution and its coefficient of variation appear to be overestimated, apparently because of the sampling scheme used to generate data for the NONMEM analysis. Suggestions for the effective use of NONMEM in clinical trials, to maximize the benefits of this approach, are provided. Our results lend further support for the use of NONMEM to estimate population pharmacokinetic parameters of a drug from data generated during phase III clinical trials.
Administration, Oral↗
Peroperative staging of renal carcinoma. A methodologic comparison.
Angiography, computed tomography and ultrasonography were compared with respect to staging of renal carcinoma in 41 patients with 46 renal tumours. Angiography and ultrasonography gave correct staging in 52% and 48%, respectively, while correct staging was achieved with computed tomography in 80% of the tumours.
Adenocarcinoma↗
Computer-aided detection of microcalcifications in mammograms. Methodology and preliminary clinical study.
The authors investigated the feasibility of using computer methods for automated detection of clustered microcalcifications on clinical mammograms. A new difference-image approach using a matched filter/box-rim filter combination effectively removed the structured background from the image. A locally adaptive gray-level thresholding technique was then used for extraction of the signals from the resulting difference image. Signal-extraction criteria based on the size, contrast, number, and clustering properties of microcalcifications were next imposed on the detected signals to distinguish true signals from noise or artifacts. The detection accuracy of the computer scheme was evaluated by means of a free response receiver operating characteristic (FROC) analysis. It was found that, for simulated subtle microcalcifications superimposed on normal mammograms, the difference-image approach with a matched filter/box-rim filter combination could yield a true-positive cluster detection rate of 80% at a false-positive detection rate of one cluster per image. In a study of 20 clinical images containing moderately subtle microcalcifications, the automated computer scheme obtained an 82% true-positive cluster detection rate at a false-positive detection rate of one cluster per image. These results indicate that the automated method has the potential to aid radiologists in screening mammograms for clustered microcalcifications.
Breast Diseases↗
[Spiral computerized tomography of esophageal carcinoma--methodology, problems, results].
Computed tomography (CT) is widely recognized as a part of the routine preoperative staging in patients with esophageal carcinoma. Applying a tailored technique, CT criteria of transmural growth and infiltration of adjacent structures are highly accurate for estimating resectability. The size-based assessment of mediastinal and abdominal lymph nodes is usually reported with low sensitivity and specificity. Spiral technology (spiral CT) increases image quality by a reduction of artifacts due to respiratory motion or cardiac pulsation, higher anatomic detail, and peak vascular opacification throughout the entire examination. Thus, an improvement of diagnostic accuracy in the staging of esophageal carcinoma can be expected. Its targeted application and a comparison with the conventional technique are presented.
Adult↗
[The method and development of computer-assisted surgery].
The methodology and the state of the art of Computer-Assisted Surgery (CAS) are introduced in this paper. Computer-assisted surgery is a new high technology which uses computer science, biomedical engineering, mechanism, mathematics, surgery, and so on. Its objective is to help surgeons use multimodal data, such as CT, MRI, DSA, PET, et al. in a rational and quantitative way in order to plan and perform medical intervention. Stereotactic localization method and registration are two cruxes in computer-assisted surgery. There are several methods for localization and registration. In recent ten years, computer-assisted surgery has been a cynosure of scientists. Some computer-assisted surgery systems have been used in clinical practice.
General Surgery↗
Electron cryomicroscopy of biological machines at subnanometer resolution.
Advances in electron cryomicroscopy (cryo-EM) have made possible the structural determination of large biological machines in the resolution range of 6-9 angstroms. Rice dwarf virus and the acrosomal bundle represent two distinct types of machines amenable to cryo-EM investigations at subnanometer resolutions. However, calculating the density map is only the first step, and much analysis remains to extract structural insights and the mechanism of action in these machines. This paper will review the computational and visualization methodologies necessary for analysis (structure mining) of the computed cryo-EM maps of these machines. These steps include component segmentation, averaging based on local symmetry among components, density connectivity trace, incorporation of bioinformatics analysis, and fitting of high-resolution component data, if available. The consequences of these analyses can not only identify accurately some of the secondary structure elements of the molecular components in machines but also suggest structural mechanisms related to their biological functions.
Capsid Proteins↗
[Computer-assisted plethysmographic vascular diagnosis: new methodologic aspects].
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Arterial Occlusive Diseases↗
Ab initio computation of low-temperature phase diagrams exhibiting miscibility gaps.
A new methodology for the computation of the low-temperature part of phase diagrams without recourse to any experimental information is presented. A central element is a procedure for deciding whether formation of crystalline solid solution phases can take place in the chemical system. Via global exploration of the enthalpy landscapes for many different compositions in the system, candidates for ordered stoichiometric and crystalline solid solution phases are identified. Next, their free enthalpies are computed at ab initio level and a low-temperature phase diagram is derived. As examples, the low-temperature phase diagrams for the ternary alkali halides NaCl/LiCl NaBr/LiBr and NaCl/KCl are presented.
Algorithms↗
Imaging the structure of the striatum: a fractal approach to SPECT image interpretation.
The spatial pattern of striatal dopamine transporter density in the living human brain was tested by duplicate SPECT scans with [123I]PE2I, [123I]beta-CIT or [123I]beta-CIT-FP and striatal phantom measurements. The resolution-dependent spatial variation was calculated by the fractal analysis of SPECT images. This variation, which depends on the size of the region of interest, was described by the spatial dispersion i.e. the standard deviation of the count densities divided by the mean density. In each sub-region, the observed and methodological dispersions were computed, and the resulting spatial dispersion was calculated. The methodological dispersion is caused by the imaging resolution, flood field non-uniformity, count density, scatter, reconstruction errors and partial volume effects, whereas the spatial dispersion is based on the cerebral heterogeneity of the dopamine transporter density. Recognition of the normal variation in heterogeneity is important in evaluation of the striatal dopamine transporter density between controls and patients suffering from various neuropsychiatric disorders.
Adult↗
Assessment methodologies and statistical issues for computer-aided diagnosis of lung nodules in computed tomography: contemporary research topics relevant to the lung image database consortium.
Cancer of the lung and bronchus is the leading fatal malignancy in the United States. Five-year survival is low, but treatment of early stage disease considerably improves chances of survival. Advances in multidetector-row computed tomography technology provide detection of smaller lung nodules and offer a potentially effective screening tool. The large number of images per exam, however, requires considerable radiologist time for interpretation and is an impediment to clinical throughput. Thus, computer-aided diagnosis (CAD) methods are needed to assist radiologists with their decision making. To promote the development of CAD methods, the National Cancer Institute formed the Lung Image Database Consortium (LIDC). The LIDC is charged with developing the consensus and standards necessary to create an image database of multidetector-row computed tomography lung images as a resource for CAD researchers. To develop such a prospective database, its potential uses must be anticipated. The ultimate applications will influence the information that must be included along with the images, the relevant measures of algorithm performance, and the number of required images. In this article we outline assessment methodologies and statistical issues as they relate to several potential uses of the LIDC database. We review methods for performance assessment and discuss issues of defining "truth" as well as the complications that arise when truth information is not available. We also discuss issues about sizing and populating a database.
Algorithms↗
The Section on Medical Expert and Knowledge-Based Systems at the Department of Medical Computer Sciences of the University of Vienna Medical School.
The Section on Medical Expert and Knowledge-Based Systems at the Department of Medical Computer Sciences pursues methodological research in and practical development of knowledge-based computer systems to assist in the decision-making processes for all areas of medical application. Vagueness of medical terms, uncertainty in the co-occurrence of medical entities, and incompleteness in medical theories are well-known characteristics of medical knowledge and ought to be considered in practically-used medical knowledge-based systems. We found that fuzzy set theory and fuzzy logic are powerful theories that model the above-mentioned characteristics. Fuzzy set theory and fuzzy logic were applied in the following systems: CADIAG-II and MedFrame/CADIAG-IV, FuzzyARDS, and FuzzyKBWean. CADIAG-II and MedFrame/CADIAG-IV are framework programs for consultation systems to aid in the differential diagnostic process in internal medicine. FuzzyARDS is an intelligent on-line monitoring program of data from patients with acute respiratory distress syndrome (ARDS) at an intensive care unit (ICU). It employs fuzzy trend detection and fuzzy automata. FuzzyKBWean is an open-loop fuzzy control program for optimization and quality control of the ventilation and weaning process of patients after cardiac surgery at the ICU. The above-mentioned computer systems have reached the state of extensive clinical integration and testing at the Vienna General Hospital. The obtained results show the applicability and usefulness of these systems.
Artificial Intelligence↗
Computer administration of a school-based adolescent health survey.
OBJECTIVE: To examine the utility of notebook computers in the collection of data in large scale surveys. METHODOLOGY: A notebook computer administered survey of health in adolescents was conducted in 1992 using a multi-instrument questionnaire. Students in school years 7, 9 and 11 in private and government schools in Melbourne and rural Victoria participated. RESULTS: Parental consent was obtained with an 83% response rate. Each student answered questions directly onto the computer taking an average of 68 min to complete the highly branched confidential but not anonymous questionnaire. Students were presented with on average 33% of the 897 possible questions. Over 90% of students reported enjoying using the computer. Those who reported answering the questions honestly all the time ranged from 68 to 85%, increasing with grade level. CONCLUSIONS: The use of computers in survey research provides many advantages in data collection including exposure only to relevant questions and the opportunity of asking sensitive questions.
Adolescent↗