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At least 613 records · Page 34Linked to original sources
PubMed1990

New approach to analysis of rotational panoramic radiography by computer simulation.

Computer simulation is an effective method for mathematical analysis of the image of rotational panoramic radiography. Conventional simulation methods have been used only for analysis of imaging factors and prediction of the characteristics of the obtained image. This paper describes a new computer simulation method that analyzes the imaging factors and produces the simulated image itself. The simulation is carried out by reproducing the actual image formation process in the computer. The head phantom for simulation, which represents the human dentomaxillofacial structures as a numerical value from 0 to 4, was constructed by scanning a real head phantom from neck to head with an X-ray CT scanner at a slice thickness of 1 mm and at 1 mm slice intervals. The diverging X-ray beam was expressed as a set of straight lines and was moved according to various parameters. The simulated image obtained was satisfactory for image analysis of rotational panoramic radiography.

Computer Simulation↗
PubMed1990

[Quantitative study on esophageal cytology. I. Quantitative morphologic studies of normal, dysplastic and malignant squamous cells].

On cytosmears of esophageal epithelium of individuals from high-risk area of esophageal cancer squamous epithelial cells, according to standard cytologic diagnostic criteria, can be categorized as normal, hyperplasia, severely dysplastic grade I and grade II, nearly-carcinoma and early carcinoma. Cytosmears from 60 patients, 10 for each category, were studied with a semiautomatic image analysis system. Thirteen morphologic parameters so obtained were further analyzed by computer-based stepwise regression and linear correlation analyses. The results showed that the following 5 parameters could be used to judge the nature of the cells, i.e. a) cytoplasmic area, b) cytoplasmic mean diameter, c) cytoplasmic form factor, d) nuclear form factor and e) N/C ratio. Comparing with cells of the other categories, values of the first 4 parameters for early cancer cells were decreased whereas that of the fifth parameter was significantly increased. From normal to hyperplastic and to dysplastic cells, the nuclear area and mean nuclear diameter were gradually increasing. Therefore, they were the major parameters in judging the degree of hyperplasia and dysplasia. These numerical features of morphologic quantitation conformed with the cytologic diagnostic criteria for cancer, hyperplasia and dysplasia under light microscope. It indicates that visual judgement is relatively accurate and application of the ocular micrometer to measure the cells would make this grading more objective.

Cell Nucleus↗
PubMed1988

Quantitative rose bengal staining technique for external ocular diseases.

A new technique for quantitative assessment of rose bengal staining in ocular surface disorders is described. The globe is divided into 16 quadrants which represent clinically important regions of the eye. Each quadrant is graded numerically for intensity and area of rose bengal staining. This simple grading system facilitates mathematical study and computer analysis of ocular surface disease.

Diagnosis, Computer-Assisted↗
PubMed1978

Enlarged acid-base and blood gas calculations by electronical data computing in the blood gas laboratory.

A rapid anaysis of parameters of the acid-base equilibrium and blood gases during open heart surgery and emergency therapy is absolutely necessary. Computing of the several parameters of the acid-base status by slide rules or nomograms is time consuming and can be shortened by computer applications. The central blood gas laboratory consists of a blood gas analyzer for PO2, PCO2 and pH, an electronic desktop calculator, a four color X-Y-plotter and two data lines to the cardiac surgery unit and to the intensive care unit. The time needed for computing and feedback of the parameters could be decreased to one quarter. In addition to numerical data printout, a graphical representation of the several parameters is possible on a X-Y-plotter and includes the Rahn-Fenn-O2-CO2-Diagram with venous admixture, ventilation perfusion ratio, alveolar dead space ventilation and the standard and actual oxygen dissociation curve as well as the pH/HCO3- Acid-Base nomogram. Furthermore, a computer diagnosis of the actual disturbances can be plotted.

Acid-Base Equilibrium↗
PubMed1987

The emerging prominence of computer electrocardiography in large population-based surveys.

The year 1987 marks the centennial of electrocardiography. As Beamish reminds us, it was the first and foremost technical aid to the cardiologist. During the history of cardiovascular epidemiology, which dates back roughly forty years, electrocardiography has played a central role as a relatively specific marker for coronary and hypertensive heart disease. The lack of sensitivity of electrocardiography and the advent of new technologies such as ultrasonography for assessment of such heart disease in cardiology and cardiovascular epidemiology has raised questions as to whether electrocardiography might be replaced in the next century. Recent developments in computer electrocardiography have rendered suggestions of the decreased importance of electrocardiography premature. Use of computer analysis of electrocardiograms in epidemiologic studies, which dates back less than three decades, has renewed interest in and expanded the role of electrocardiography in cardiology in general and cardiovascular epidemiology in particular. The computer analysis of electrocardiograms has allowed the processing and analysis of large numbers of electrocardiograms in a rapid, efficient, systematic and consistent manner. This has led to new, more sensitive criteria for detection of left ventricular hypertrophy as a discrete variable. In addition, the numerous waveform amplitude and duration measurements by computer have allowed the development of mathematical models to express the likelihood of coronary heart disease (myocardial infarction) and degree of left ventricular hypertrophy (estimates of left ventricular mass) on continuous scales. These developments have contributed substantially to the potential of electrocardiography (and particularly computer electrocardiography) in future studies and clinical applications.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiomegaly↗
PubMed1988

The use of multiple logistic function to predict surgical risk.

A method for preoperative assessment of surgical risk, in function of several risk factors, was developed using the multiple logistic function, as a model of multivariate statistical analysis. This model has the advantage to express the two considered outcomes (perioperative complications and death) in numerical terms of probability. The data were obtained from 8630 consecutive patients admitted to 62 hospitals located in various regions of Italy. The patients were divided at random into two groups: group A (6040) was used to develop the method, and group B (2590) was used as control. The method is based on the role played by seven risk factors, that were shown to be significantly related to the two outcomes. These factors are age, systolic blood pressure, pathological changes of renal function, presence of concomitant diseases, estimated duration of surgical procedure, type (major or minor) and timing of surgery, (elective, delayed or emergency). The relative and independent role of each of these factors (beta) and the value of constant alpha were estimated by maximum likelihood method. The surgical risk is assessed by solving the multiple logistic equation, and multiplying the beta values by the corresponding individual coded values of the risk factors represented by the various x's. When the method was tested by applying the computed values of alpha and beta's to assess the outcomes in the control group, the predictions resulted highly accurate (r = 0.99). To simplify the calculation of surgical risk, in appendix a computer program in Basic, already predisposed to receive in code the individual values of x's, is reported.

Adolescent↗
PubMed1977

[Multivariant discriminance analytical computation methods for the evaluation of clinico-chemical parameters in liver and biliary tract diseases].

Multivariate variance and discriminance-analytic investigations on the value of evidence of clinico-chemical tests in the diagnostics of diseases of the liver and the biliary tract gave the following results: 1. By means of clinico-chemical methods and discriminance-analytic functions we succeed in 50% of the cases in formulating a correct diagnosis, in more than 75% of the cases a correct probability diagnosis (3 first places in the rank of diagnoses). Sensitivity and specificity of discrimination were established for 15 classes of diagnoses. 2. Due to the intercorrelations of test results biochemical maximum programmes contain numerous redundant parameters measured on diagnostic information values. With the help of a test for indispensability (redundance test) among 20 parameters owy 5-6 were characterized as indispensable. An optimal combination of parameters should not transgress an extent of 14 tests. 3. Results of reclassifications with discriminance analytic functions confirmed that the discriminance analysis is an extraordinarily suitable method for the computer-supported finding of a decision, on which basis aimed additional investigations might be performed.

Analysis of Variance↗
PubMed1977

[Nystagmus analysis by computer (author's transl)].

Automatic quantitative nystagmus analysis by means of a digital computer primarily gives a lot of data. Analysis then means reducing this amount of numerical data to a few relevant results. Because the diagnostic importance is not known yet for all available nystagmus parameters, this implies the risk of losing essential informations. Therefore, limitations of the number of parameters as well as of the duration of the investigated intervals by the method of analysis have to be avoided. This then allows studying the diagnostic value of new parameters (e.g. of the fast components) or the time course of reaction intensity. From this point of view a method of quantitative nystagmus analysis is described.

Computers↗
PubMed1987

Gallium-67 lung index computerization in interstitial pneumonitis.

To improve ease of use, precision, and reduce interobserver variability of the 67Ga lung index, we developed and tested a computer method that yields similar numeric values and uses previous indexing principles, except that the computer matrix unit is the fractional area assessed. Patients were referred for suspected interstitial lung disease. Fifty-three image studies were available for both manual and computer indexing. Linear regression analysis gave a correlation of 0.884. Decision matrix analysis of 58 different nonimmunosuppressed patients resulted in 93% sensitivity and 76% specificity. Receiver operating characteristic curve analysis showed that the ideal index cutoff was 50. Because there is tighter control over 67Ga uptake intensity and spatial distribution assessment, the computerized 67Ga index appears to perform better than the manual analysis.

Gallium Radioisotopes↗
PubMed1979

[Objectivation of tremor and motion disorders via computerisation (author's transl)].

The quantitative analysis of motion disorders of the upper extremities can be performed by means of a joystick connected with a minicomputer. Therefore a random squarewave curve is drawn on a computer display and the patient must follow it with the joystick. The deviation of the two curves are recorded, analysed and documented numerically and graphically.

Diagnosis, Computer-Assisted↗
PubMed1984

[Computer-assisted findings on protein electrophoresis on cellulose acetate film].

Until a short time ago efficient computer assisted reporting of electrophoretograms was not possible owing to the lack of appropriate technology. By integrating a fully mechanized electrophoresis system into the laboratory data processing system of a centralized institute of clinical chemistry, the separation and the interpretation of results can be performed for 300 samples per day. The interpretation is based upon available patient data (specified clinical diagnoses, previous results), calculated fractions and analysis of the electrophoretic curve in the area of albumin and the beta- and gamma-globulin fraction. In this way it is possible to classify hereditary bisalbuminaemias and to detect transient bisalbuminaemias and monoclonal gammopathies. Diagnostic indications of specific dysproteinaemias and defect proteinaemias are printed on the report form if individual serum protein fractions and the total protein content are changed specifically. The results of the different electrophoretic fractions, the total protein and a set of possible alterations of the curve are numerically coded according to the scaled biochemical ranges in five definite sections or to a decision matrix (alteration 'given' or 'not given'), respectively. The composed 'result patterns' are matched with preassigned 'reference patterns' stored in the computer file. The procedure is efficient and adaptable to other areas of analysis.

Albumins↗
PubMed1983

[Correlations between EEG (FFT) and the degree of consciousness in patients in the early post-traumatic phase].

In 73 comatose patients after cerebral trauma a computer-assisted study was done prospectively in relation to the clinical findings, the course, morbidity, and mortality as well as computer analysed EEG. The patients were examined at the 3rd, 6th, and 9 th day after trauma. The state of consciousness was scaled in 10 points and correlated to the numerous EEG results (spectral analysis and power in the delta-, sigma-, alpha-, and beta-range). As well it shows, the alpha-band gives the best correlation to the clinical findings and permit a certain prognosis.

Adolescent↗
PubMed1995

Neurophysiologic assessment in the management of spinal dysraphism.

Neurophysiologic techniques provide a valuable addition to the armamentarium of tools for the evaluation of sensory and motor function in the pediatric spinal cord. These techniques include median, radial, and ulnar nerve evoked potentials from the upper extremity; common peroneal and tibial nerve evoked potentials from the lower extremity; dermatomal potentials; and compound muscle action potentials and compound nerve action potentials. The techniques that evaluate the sensory system have been used extensively and effectively as research tools, as adjuncts to diagnostic evaluation, and for intraoperative monitoring. There is a considerable literature that describes the properties of SEPs in the infant and young child. Techniques for assessing the descending pathways have been developed in the last 10 years. These techniques hold great promise as both diagnostic and intraoperative monitoring tools. Many questions, however, still exist concerning their value and use. The rapidly increasing capability available in computer systems is also providing enhanced capability in the acquisition, display, and analysis of neurophysiologic data. It is now common to acquire multiple responses simultaneously, e.g. tibial SEPs, pudendal SEPs, and motor potentials. It is also possible to apply computationally intensive numerical algorithms in real time to enhance signal quality and reduce the time required to produce an interpretable display. Finally, it is possible to monitor multiple cases simultaneously from remote locations. These enhanced computational capabilities are helping to optimize the contribution of neurophysiologic monitoring to patient care.

Child↗
PubMed1994

Recovery from propofol anesthesia: a quantitative electroencephalographic analysis.

Four numerical descriptors (median frequency, spectral edge frequency-95%, total power, and delta-ratio) derived from the computer-processed electroencephalogram (Neurometrics Lifescan) were analyzed for their ability to predict imminent arousal from total intravenous anesthesia with propofol. Fifteen patients undergoing minor surgical procedures without intubation were enrolled in the study. Arousal was defined as eye opening in response to verbal stimuli. During emergence from propofol, there were no significant changes among the descriptors except the delta-ratio. Significant change of delta-ratio occurred 210 seconds before patients' arousal and thereafter. An increase of delta-ratio value indicates that patients shifted from anesthetic to arousal state. It is concluded that the degree of delta-ratio change may be used for predicting patients' arousal from propofol anesthesia.

Adult↗
PubMed1994

Waveform and latency estimation from neuroelectric signals using the bispectrum.

A technique based on bispectra and cross-bispectra is described for estimating waveform and latency from a set of noisy signals with variable latency. Waveform estimation is performed by averaging bispectra of observed noisy signals. Latency estimation is performed by using the product function of a function derived from the cross-bispectrum and the cross-correlation. The method is numerically assessed by simulations, using a signal with uniformly distributed latency and computer-generated noise sequences.

Electroencephalography↗
PubMed1977

Development of food tables and use with computers. Review of nutrient data bases.

Numerous tables of food composition have been compiled since the 1890s to meet the needs for nutrient data by nutritionists, researchers, and consumers. Early tables included values for protein, fat, carbohydrate, and calories. By 1945, values for several vitamins and minerals were listed in tables of food composition. The contents of food composition tables have been updated and expanded as laboratory procedures for analyzing nutrients have been improved. A trend toward increased specificity for most nutrient classifications has resulted in consideration of up to one hundred nutritional components in the development of nutrient data bases. Tables of food composition have varied in number of food items, number of nutrients, and classification schemes. Food-group designations have been used in some tables as a technique to categorize data for similar food items. Computer-stored nutrient data bases tend to vary in much the same manner as printed tables of food composition. Computer-assisted diagnostic procedures for editing input data for validity and verifying reasonable relationships among nutrient data have been developed to detect data inconsistencies. As data for new food products are included and the effects of food processing methods are determined, food composition tables and computer-stored nutrient data bases are expected to become more comprehensive, reliable, and suitable for various uses.

Calorimetry↗
PubMed1993

Real-time identification of parameters of the ARMA model of the human EEG waveforms.

Electroencephalogram (EEG) can provide important information about the functioning of the human brain. In particular, the EEG waveforms manifest certain changes due to application of drugs, such as general anesthetics. Measurement of the changes in the EEG waveforms in real time, may therefore be used to determine the global effects of the administered drug. Among numerous mathematical techniques used in the analysis of the EEG waveforms, perhaps, the fast Fourier transform (FFT) is the most widely used. Recently some researchers have suggested the use of the autoregressive moving average (ARMA) model for the EEG analysis. In this method the coefficients of the ARMA model are identified and used to describe the waveform. We consider a first order ARMA model, and use the Extended Least Squares (ELS) and its recursive version (RELS) for parameter estimation. The identified parameters are then used to describe the time-domain or the frequency-domain properties of the EEG waveforms. Since the parameters of the model may change with time, a forgetting factor is incorporated in the RELS algorithm to allow for tracking of time varying parameters. The advantage of recursive estimation of the coefficients of the ARMA model over the non-recursive estimation and the FFT method, is substantial reduction in computation as well as its capability to track the time varying process.

Algorithms↗