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PubMed1983

Computerized medical records. A new resource for clinical decision making.

A computerized medical record changes the way a clinician practices medicine by presenting data about patients in multiple organized formats. A computerized record can be used to make it more difficult to overlook important findings. The computer can improve communication by informing both the patient and referring physicians of new data as they become available. Computer graphics or algorithms can be used to emphasize subtle trends. A computer data base can be used to aggregate data about selected patients to provide information about the natural history of disease and effect of treatment.

Computers↗

PubMed1999

Estimates of shape by eye, or, the little invariant that could.

Five experiments were conducted to test the hypothesis that observers apprehend specific constancies under change in perspective. The constancies were projective properties of ellipses pictured to slant and tilt in depth. Observers were asked to reproduce the static upright view of a moving pair of ellipses, using a computer graphics display and interface. Projective invariants for pairs of conics were computed on the observers' productions. A few experimental conditions revealed near-perfect performance. When pairs of coplanar ellipses were viewed under dynamic transformation in perspective, then invariants calculated on the observers' productions were a match--in value on average--to the invariants of the transforming ellipse pairs. It is proposed that measures of projective properties afford a family of techniques that can be applied to gauge acuity for complex shapes in the study of visual form perception.

Analysis of Variance↗

PubMed1993

Modeling the three-dimensional structure of RNA.

The limited number of RNA structures determined by X-ray crystallography and NMR spectroscopy compels the use of experimental and theoretical methods that are less precise to obtain information on RNA conformation. RNA flexibility, a consequence of rotational freedom about seven intra- and internucleotide bonds, is unfortunately of such magnitude that these alternate techniques fall short of providing sufficient information to build robust tertiary structures. Various RNA modeling methods, described herein, permit the organization of this structural data to the form of three-dimensional structures. Interactive computer graphics techniques, for example, have generated several useful models. Also, conventional computer algorithms involving the minimization of empirical energy functions, previously limited to small molecules, are giving way to methods able to handle much larger molecules. Modified distance geometry and molecular mechanics algorithms, using simplified "pseudoatom" representations, can generate structures consistent with input data. A constraint satisfaction algorithm combined with discrete representations of nucleotide conformations systematically explores poorly defined regions of a molecule yielding all-atom representations, but requires enough structural constraints to avoid a computational explosion.

Algorithms↗

PubMed1980

Interactive display of molecular models using a microcomputer system.

An interactive graphics display system (IGDS) which presents perspective views of wire frame models is described. The display unit is a microprocessor driven TERAK 8510a system with a grid of 320 . 240 points. A brief discussion of the hardware is given. While the system is quite general - it can draw a perspective view of any type of wire frame model - emphasis here is on molecular models. The graphics software has been written in UCSD PASCAL. The program employs traditional computer graphics algorithms available in the literature, The data structure used by the program was designed to occupy minimal disk storage space. Data files can be constructed locally or can obtained through a communications link with with a central computer facility. Despite the inherent slowness (due to matrix operations being performed by the software calculations rather than hardware), the low cost of the system suggests general applicability. The program is easy to use, interactive, and produces good results from systems up to 200 points.

Computers↗

PubMed1976

Computerised assessment of cardiac pacemaker performance.

The design and use of a PDP 11/40 based automated on-line cardiac pacemaker assessment system is described. One program has been developed for testing pacemakers on the bench and another for implanted pacemaker tests. Either fixed rate or demand pacemakers can be tested. The on-line system is easy and fast to use and is also highly accurate. Parameters extracted are pulse width, rate and pulse energy. In addition, a graphical representation of the patient's ECG and the pacemaker pulse is obtained on a computer graphics terminal.

Computers↗

PubMed1996

Effects of age and disability on tracking tasks with a computer mouse: accuracy and linearity.

Many individuals with movement disorders are unable to make efficient use of graphical computer interfaces commonly employed in personal computers. In this study, performance limitations in target tracking with a computer mouse were studied for eight young subjects aged 19 to 29 (M = 23, SD = 3), four old subjects aged 70 to 73 (M = 72, SD = 1), and five motor-disabled subjects aged 37 to 74 (M = 65, SD = 16). Subjects tracked simple one- and two-dimensional motions at various frequencies. Performance was measured using an accuracy index derived from root-mean-square error, and a linearity index based on coherence estimation. A maximum bandwidth of 2 Hz for accuracy of mouse use was found, which often decreased due to advanced age or motor disability. Tracking linearity of all groups decreased as frequency increased. A significant degree of nonlinearity existed in all results (p < 0.05), with disabled subjects nearing complete nonlinearity in two-dimensional tracking. The data show that with advanced age and disability, mouse use becomes increasingly inaccurate and nonlinear. Assistive computer interfacing techniques, such as signal filtering, may improve mouse use.

Adult↗

PubMed1982

Three-dimensional computer reconstructions of brain lesions from surface contours provided by computed tomography: a prospectus.

We present a prospectus on the use of computer graphics for the three-dimensional reconstruction and visualization of brain lesions from computed tomographic head examinations, including an algorithm that utilizes surface contour information to reconstruct and display three-dimensional anatomical sites. We provide examples of the use of this algorithm. We offer an algorithm for estimation of the volume and surface area of anatomical sites. The advantages and disadvantages for the clinical use of these algorithms are discussed.

Adenoma, Chromophobe↗

PubMed1993

Standards for medical graphics.

A lack of understanding of simple standards is responsible for poor quality graphics in slides, overhead projection transparencies, posters and publications. The ready availability of computer graphics application programs has led to a proliferation of well-executed, but poorly constructed illustrations. Guidelines are given for the design of scientific illustrations, with reference to correct labelling, line weights, font styles and sizes, the use of colour, and other factors affecting the clarity of presentation. The application of established standards for the preparation of medical graphics as described is strongly recommended.

Audiovisual Aids↗

PubMed1997

Doctor friendly electronic patient record.

In this paper we would like to show importance of using modern information technology in implementation and development of health information systems. Our main focus is on doctor's work. Doctors will use computer only if they will see clear advantages. Traditional data gathering and display are not sufficient, so modern software should provide speech interfacing and computer graphics in various applications and enable the use of electronic mail, hand held computers, electronic data interchange, etc. among other features. This paper tries to show the needs for applications of those features. They are already implemented as part of our hospital information systems.

Computer Communication Networks↗

PubMed1988

Computer emulation of thin section electron microscopy predicts an envelope-associated icosadeltahedral capsid for human immunodeficiency virus.

Electron microscopy of human immunodeficiency virus (HIV) has provided evidence for a virion model which when sectioned, consists of a circular envelope surrounding an inner conical core. When sections are perpendicular to the core axis, the envelope is still circular, but the tapered core appears as a dot near the center of the envelope. An observation inconsistent with the present model is the frequent finding of an electron-lucent "polygonal window" associated with the virion envelope. Here, we provide evidence for a new model of HIV. This model, which accounts for the polygonal windows and the shape of the envelope, places the conical core inside a regular polyhedron that lies just under the envelope. We tested the validity of various polyhedrons with three-dimensional computer graphics which emulate thin section electron microscopy. With this technique, about 2000 computer-generated "thin sections" of HIV-models were compared with electron micrographs of HIV. A structure consistent with the computer-generated data reveals a detailed model for HIV with the following features; (a) the conical core is inside an envelope-associated capsid having icosadeltahedral symmetry. This envelope-associated capsid is 60-sided and contains 32 vertices, 20 of which have hexagonal symmetry and 12 of which have pentagonal symmetry, (b) the inner rodlike core abuts the inside of any 2 opposing hexagonal vertices, (c) the pentagonal vertices do not support the inner core. A comparison of these results with that of Gelderblom et al. (Gelderblom HR, Hausmann EHS, Ozel M, Pauli G, Koch MA: Fine structure of HIV and immunolocalization of structural proteins. Virology 156: 171, 1987), suggests that the p17 polypeptide is a component of the envelope-associated icosadeltahedral capsid. This computer emulation technique provides a thorough test of this model of HIV, but does not constitute proof. Additional testing methods such as bidirectional metal shadowing and freeze etching will be needed to confirm this new virion structure. Additionally, this computer technique may be useful for testing the proposed morphology for cell organelles.

Capsid↗

PubMed1989

[Graphic assessment of retinal findings by computer].

Despite the increasing amount of patient data in the area of words and numbers that is being stored by computer, the graphic storage of ophthalmological findings has found only limited success. However, a sketch is much more instructive than a description in words. This paper shows that by using a suitable computer with a graphic oriented disc-operating system and a purchasable graphic and data base program, it is easily possible to generate sketches of retinal detachment on a computer screen. In the graphic program, all of the necessary symbols are already available when the program is started. The user just makes a copy of the symbols he needs to "draw" the actual fundus findings. We use the system of Meyer-Schwickerath. Afterwards, the drawing on the monitor is transferred into the data base program and stored.

Computer Graphics↗

PubMed1984

An interactive microcomputer-based graphics system for analysis of cardiodynamic function.

An on-line interactive, modular, menu-driven microcomputer-based data acquisition and analysis system was designed and implemented. This system includes a low-cost commercial desk-top graphics computer with a modular construction. All these operations are performed using extended BASIC "CALL" statements. The system is designed to be used in a cardiovascular research and laboratory environment where the assessment of hemodynamic and cardiodynamic function includes routine measurements of pressure and flow. In addition, the measurement of regional and global left ventricular chamber dimensions have been implemented. The modular design of the software system is "human-engineered" to enable a simple, cost effective computer system to perform physiological measurement and control. Extended BASIC language instructions provide the casual computer user with a simple yet effective means of implementing on-line data acquisition, analysis and graphic production and display.

Cardiovascular Physiological Phenomena↗

PubMed1999

New evidence from Le Moustier 1: computer-assisted reconstruction and morphometry of the skull.

In this study, we present a new computerized reconstruction of the Le Moustier 1 Neanderthal skull and discuss its significance for Neanderthal growth and variability. Because of the precarious state of preservation of the original material, we applied entirely noninvasive methods of fossil reconstruction and morphometry, using a combination of computed tomography, computer graphics, and stereolithography. After electronic restoration, the isolated original pieces were recomposed on the computer screen using external and internal anatomical clues to position the bone fragments and mirror images to complete missing parts. The inferred effects of general compressive deformation that occurred during fossilization were corrected by virtual decompression of the skull. The resulting new reconstruction of the Le Moustier 1 skull shows morphologic features close to the typical Neanderthal adult state. Residual asymmetry of skeletal parts can be traced to in vivo skeletal modification: the left mandibular joint shows signs of a healed condylar fracture, and the anatomy of the occipital region suggests mild plagiocephaly. Using micro-CT analysis, the left incus could be recovered from the matrix filling of the middle ear cavity. Its morphometric dimensions are similar to those of the La Ferrassie III incus. The morphometric characteristics of the inner ear deviate substantially from the condition reported as typical for Neanderthals and fall within the range of modern human variability.

Animals↗

PubMed1976

Computer visualization of flow patterns for prosthetic heart valves.

Flow patterns for commonly used aortic valve prostheses were formed with the aid of fluid dynamics equations, numerical analysis techniques and computer graphics. Simulations of velocities, vorticity, pressure and certain stress values were developed by a computer and displayed for man-machine interaction. The ball, disc and tilting-disc occluders were of interest. The displays comprised both contour and perspective patterns; the latter permitting semi-quantitative evaluation of particular parameters. Comparisons between the computer simulations and those flow visualizations formed by Björk and co-workers were assessed. Although the methodology was of prime concern for presentation, the capability of the tilting-disc prosthesis for presenting a more natural flow regime was shown. Thoughts of future studies were entertained.

Aortic Valve↗

PubMed1977

Vector cardiographic assessment of implanted cardiac pacemakers.

The design and use of an on-line PDP 11/40 based vector cardiographic pacemaker assessment system is described. The system has been designed for comprehensive, automated testing of either fixed rate or demand implanted cardiac pacemakers. It is accurate and can be operated by a laboratory assistant without special training. Pacemaker parameters extracted are pulse height, width, rate, energy index and the frontal plane vector length and angle at maximum inspiration and during quiet breathing. In addition, a graphical representation of the patient's ECG and the pacemaker pulse is obtained on a computer graphics terminal. Patient data are written to cartridge disk for permanent record following the test. At each subsequent test of the implanted pacemaker, the data on disk are addended with the latest quantitative results. A separate off-line FORTRAN program can interrogate disk files for detailed analysis of patient data and display of parameter trends since implantation.

Computers↗

PubMed2002

A mathematical formula to calculate the theoretical range of motion for total hip replacement.

The reduced range of motion (ROM) resulting from total hip replacement (THR) leads to frequent prosthetic impingement, which may restrict activities of daily living and cause subluxation and dislocation. Therefore, to know the ROM of THR is very important in clinical situations and in the design of prostheses. THR involves a pure ball and socket joint. We created a mathematical formula to calculate the theoretical ROM of THR limited by the prosthetic impingement. The ROM of THR is governed by the following five factors, (1) The prosthetic ROM (oscillation angle: obtained from company data), (2) cup abduction (3) cup anterior opening, (4) the angle of the femoral neck component from the horizontal plane, and (5) the femoral neck anteversion. The last 4 factors are able to be obtained from anterior-posterior, axial X-rays and CT of the patient's THR. The objective was to create mathematical formulas that could accurately and quickly calculate the ROM of THR. By entering the five values into a computer programmed with the formulas, one could obtain the ROM for the THR. This reveals the effect on ROM of the oscillation angle and the interaction of ROM with cup abduction, anterior opening and neck anteversion. Furthermore this readily would enable a clinical evaluation of the possibility of postoperative dislocation and help in postoperative rehabilitation. The calculated numerical values of ROM by these mathematical formulas were successfully compared with the ROMs obtained from 3-dimensional computer graphics (3D-CG).

Biomechanical Phenomena↗

PubMed1986

Interactive display of three-dimensional radionuclide distributions.

Tomographic images of three-dimensional radionuclide distributions are usually presented as a set of parallel planar slices. A technique has been developed to enable the observer to perceive directly the three-dimensional morphology of the activity distribution by displaying iso-count surfaces. Computer graphics techniques have been used to present shaded surface images using a conventional nuclear medicine computer system. Because of the relatively coarse spatial sampling of radionuclide tomograms, a smooth shading algorithm based on a local polynomial fit procedure was developed. By using a simple solid model approach for data storage the program executes interactively, allowing the observer to view the reconstructed activity distribution from any aspect. The technique has been successfully applied to radionuclide tomograms of several organs, and promises to be particularly useful for the display or cardiac blood pool data.

Algorithms↗

PubMed1997

[Puerperal infection. Analysis of 618 cases].

From September 1993 to March 1995 a prospective, descriptive study was performed at Obstetrical Department of the General Hospital 2A the Mexican Institute of Social Security. An attempt to know the real puerperal infection incidence in our own hospital to be able to make hypothesis and take specific measures in puerperal infection control. Dairy account of interesting data of cases under inclusion criteria. Entering data in personal computer. Graphics and analysis were accomplished using Lotus 123, Statgraphics, EPI-6 of CDC and Freelance computational programs. Search of central tendency measures were performed, (media, median, mode, standard deviation). Odds ratio and relative risk were calculated, including hospitalization time and its temporary variation to data cross. X square and pi were including hospitalization time and its temporary variation to data cross. X square and pi were determined to statistic validates. The cumulated rate of general puerperal infection were 1.2%. By stratification, the cumulated rate of infection after cesarean section, vaginal delivery and miscarriage were 5.4%, 0.8% and 0.3%, respectively. There was predominance of infection after cesarean section, over infection after vaginal delivery and after miscarriage. (monthly media of 24.6, 7.3 and 0.47, respectively). The puerperal infection was present principally in primiparous and in patients with one previous cesarean section. The patients in which the termination of pregnancy was by cesarean section, (0.015 infection cumulated incidence), had an infection risk 5.76 and 18.66 times greater than the patients with vaginal delivery and miscarriage. (Relative risk of 6.76 and 19.66) The site of puerperal infection was implicated in combinations or isolated, under nine clinical situation. The five most frequent clinical situation, between these nine, in incidence order from major to minor were the following: Endometritis alone, Endometritis combined with wound abscess. Endometritis with urinary infection, complicated endometritis, (sub vesical abscess, parametritis, peritonitis, salpingitis), and wound abscess alone). The greater hospitalization time was present in cases of complicated endometritis followed by wound abscess alone or combined. Complicated endometritis, (incidence 0.0010), compel us to hysterectomy in 15 cases. No death was registered among the patients with puerperal infection studied.

Adult↗