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At least 1,099 records · Page 61Linked to original sources
PubMed1999

201Tl and 99mTc-MIBI gated SPECT in patients with large perfusion defects and left ventricular dysfunction: comparison with equilibrium radionuclide angiography.

UNLABELLED: Left ventricular ejection fraction (LVEF) is a major prognostic factor in coronary artery disease and may be computed by 99mTc-methoxyisobutyl isonitrile (MIBI) gated SPECT. However, 201Tl remains widely used for assessing myocardial perfusion and viability. Therefore, we evaluated the feasibility and accuracy of both 99mTc-MIBI and 201Tl gated SPECT in assessing LVEF in patients with myocardial infarction, large perfusion defects and left ventricular (LV) dysfunction. METHODS: Fifty consecutive patients (43 men, 7 women; mean age 61 +/- 17 y) with a history of myocardial infarction (anterior, 26; inferior, 18; lateral, 6) were studied. All patients underwent equilibnum radionuclide angiography (ERNA) and rest myocardial gated SPECT, either 1 h after the injection of 1110 MBq 99mTc-MIBI (n = 19, group 1) or 4 h after the injection of 185-203 MBq 201Tl (n = 31, group 2) using a 90 degrees dual-head camera. After filtered backprojection (Butterworth filter: order 5, cutoff 0.25 99mTc or 0.20 201Tl), LVEF was calculated from reconstructed gated SPECT with a previously validated semiautomatic commercially available software quantitative gated SPECT (QGS). Perfusion defects were expressed as a percentage of the whole myocardium planimetered by bull's-eye polar map of composite nongated SPECT. RESULTS: Gated SPECT image quality was considered suitable for LVEF measurement in all patients. Mean perfusion defects were 36% +/- 18% (group 1), 33% +/- 17% (group 2), 34% +/- 17% (group 1 + group 2). LVEF was underestimated using gated SPECT compared with ERNA (34% +/- 12% and 39% +/- 12%, respectively; P = 0.0001). Correlations were high (group 1, r= 0.88; group 2, r = 0.76; group 1 + group 2, r = 0.82), and Bland-Altman plots showed a fair agreement between gated SPECT and ERNA. The difference between the two methods did not vary as LVEF, perfusion defect size or seventy increased or when the mitral valve plane was involved in the defect. CONCLUSION: LVEF measurement is feasible using myocardial gated SPECT with the QGS method in patients with large perfusion defects and LV dysfunction. However, both 201Tl and 99mTc-MIBI gated SPECT similarly and significantly underestimated LVEF in patients with LV dysfunction and large perfusion defects.

Electrocardiography↗
PubMedDate not supplied

Computerized image analysis of nails affected by fungal infection: evaluation using digital photographs and manually defined areas.

Despite the relevant increase in clinical trials on the efficacy of various systemic and/or topical antifungal agents in onychomycosis therapy, the evaluation of the results is largely subjective. The aim of this study was to set up and ensure an objective, reproducible and reliable method to measure nail plate involvement in onychomycosis. In order to validate a specifically designed software for the computerized image analysis of affected areas of the nail, standardized clinical pictures of onychomycosis were prepared by six different clinicians using a sample of 11 affected nails. Diseased areas and total nail plates were measured both on the clinical pictures and on their drawings traced by the different clinicians on transparent tapes adhering to sample nails. The computerized procedure was undertaken by a trained operator who was not a dermatologist. The variation coefficients of measurements on clinical pictures (automatically detected) and on drawings were compared. In addition, the agreement between automatic evaluation and drawing was evaluated by means of Bland-Altman analysis. To consider the effect of possible variations linked to different operators using the computerized method, 11 clinical pictures (one for each clinical case considered) were selected and submitted to computerized image analysis by six different trained operators. The computerized detection of affected nail areas showed a coefficient of variation (vc=8.5%) lower than that observed on drawings (vc=14.7%). The two methods showed appreciable agreement, as demonstrated by Bland-Altman plot. The coefficient of variation of image analysis conducted by six different operators was very low for the total area calculation (vc=0.9%) and acceptable for pathological area detection (vc=4.8%). Based on the results obtained, we conclude that automatic evaluation is a reliable and helpful method for the measurement of the clinical involvement of the nail plate in onychomycosis and for the evaluation of therapies, since it can increase the objectivity and reproducibility of data. However, in a minority of difficult cases, expert dermatological evaluation is needed.

Humans↗
PubMed2004

Evaluation of syndromic surveillance systems--design of an epidemic simulation model.

INTRODUCTION: The paucity of outbreak data from biologic terrorism and emerging infectious diseases limits the evaluation of syndromic surveillance systems. Evaluation using naturally occurring outbreaks of proxy disease (e.g., influenza) is one alternative but does not allow for rigorous evaluation. Another approach is to inject simulated outbreaks into real background data, but existing simulation models generally do not account for such factors as spatial mobility and do not explicitly incorporate knowledge of the disease agent. OBJECTIVE: The objective of this analysis was to design a simulated anthrax epidemic injection model that accounts for the complexity of the background data and enables sensitivity analyses based on uncertain disease-agent characteristics. MODEL REQUIREMENTS AND ASSUMPTIONS: Model requirements are described and used to limit the scope of model development. Major assumptions used to limit model complexity are also described. Available literature on inhalational anthrax is reviewed to ensure that the level of model detail reflects available disease knowledge. MODEL DESIGN: The model is divided into four components: 1) agent dispersion, 2) infection, 3) disease and behavior, and 4) data source. The agent-dispersion component uses a Gaussian plume model to compute spore counts on a fine grid. The infection component uses a cohort approach to identify infected persons by residential zip code, accounting for demographic covariates and spatial mobility. The disease and behavior component uses a discrete-event approach to simulate progression through disease stages and health-services utilization. The data-source component generates records to insert into background data sources. CONCLUSIONS: An epidemic simulation model was designed to enable evaluation of syndromic surveillance systems. The model addresses limitations of existing simulation approaches by accounting for such factors as spatial mobility and by explicitly modeling disease knowledge. Subsequent work entails software implementation and model validation.

Anthrax↗
PubMed1993

[Use of spreadsheet for statistical and graphical processing of records from the ambulatory blood pressure monitor Spacelabs 90207].

The introduction of portable devices for non-invasive ambulatory blood-pressure measurement is recognized as an advance in the study of human arterial hypertension, allowing a significant improvement in the selection of hypertensive patients as well as in the analysis of the effects of antihypertensive drugs during clinical trials. The Spacelabs 90207 is a recent example of this kind of apparatus, possessing high levels of portability and being highly classified in validation studies. Nevertheless, the software of this apparatus (like other similar devices) has severe limitations in what concerns the calculation of the area under the curve of blood pressure during the time of measurement, as well as in the possibility of grouping several records in a database for easy statistic and graphic analysis of different groups of records. In order to overcome these difficulties, the authors describe the development of a group of programs, using Microsoft Excel v3.0 spreadsheets and macros, that allow a direct import of individual files from the Spacelabs software to a spreadsheet and its further processing in three phases. These three phases, which we designated by "conversion", "export to database" and "statistic and graphic analysis", will permit an easy and fast statistic and graphic analysis of selected groups of records.

Blood Pressure Determination↗
PubMed1998

A loglogistic model for altitude decompression sickness.

BACKGROUND: Altitude decompression sickness (DCS) is a potential hazard encountered during high altitude flights or during extravehicular activity in space. In this study, the loglogistic distribution was used to model DCS risk and symptom onset time. METHODS: The Air Force Research Laboratory, Brooks AFB, TX, has conducted studies on human subjects exposed to simulated altitudes in hypobaric chambers. The dataset from those studies was used to develop the DCS models and consisted of 975 subject-exposures to various altitudes, preoxygenation times, and exercise regimens. Since the risk of DCS is known to increase over time at altitude, and then decrease because of denitrogenation, the loglogistic model was fit to the data. The model assumes that the probability of DCS depends on several risk factors. Maximum likelihood estimates of the parameters were obtained using the statistical software package SAS. Cross validation techniques were provided to examine the goodness of fit of the model. RESULTS: The fitted model indicated that altitude, ratio of preoxygenation to exposure time, and exercise were the most significant risk factors. The model was used to predict the risk of DCS for a variety of exposure profiles. The predicted probability of DCS agreed very closely with the actual percentages in the database. CONCLUSION: The loglogistic distribution was found to be appropriate for modeling the risk of DCS. Based on the cross validation and validation results, we conclude that this model provides good estimates of the probability of DCS over time.

Adolescent↗
PubMedDate not supplied

[Use of the CD-ROM "Tox-Didact" for teaching of toxicology and pharmacology].

Tox-Didact is a multimedia teaching software package for initial training, continuing training and self-learning of toxicology and pharmacology. This software covers a large part of toxicology in its acute and chronic pathology using several approaches: drugs (salicylics, paracetamol, lithium ...); toxins (lead, methanol, carbon monoxide ...); drug addiction and doping (cocaine, heroin, LSD, amphetamines ...); systemic targets (kidneys, skin, liver ...). Tox-Didact is currently composed of 39 modules in validation, each tackling the diagnosis, biological surveillance, treatment, prevention and documentation of a real clinical case. Each module is organized around four types of questions, requiring a choice either (drug, symptom, formula ...) or an open response. Each validated answer is analysed by software which then comments on or corrects it. The essential points which characterize this software are: its multidisciplinarity (toxicology, pharmacology, semiology ...), its reliability (validated by experts), its simplicity of use. It is modular and offers an interactive teaching approach. The objective is to create a portable multimedia tool operational with all computer systems (IBM PC, Macintosh). This program is sustained by the Région des Pays de la Loire and by the Multimedia Resource Office of the French Ministry of National Education.

CD-ROM↗
PubMed1996

Real world data--retrieval and validation of consultation data from four general practices.

OBJECTIVE: We aimed to retrieve data on consultations from general practice databases and to develop and use appropriate methods of validation for these data. METHOD: MIQUEST software was used to retrieve the data from four practices. The data were validated by comparing them with figures generated by practice-based searches, measuring the uptake of recording of consultations over time, and comparing records of consultations in the case notes with those on the practice computers. RESULTS: The required data were retrieved from general practice databases, but the path to success was difficult, and typified by uncertainty and unpredictability. The recording of consultations on the computers of four practices was more complete than the recording in the paper case records. There was a time period in the early months of computer use when the recording of consultations was less complete. There were differences in the completeness of recording consultations between practices, doctors, and patients. CONCLUSIONS: This study confirms the potential of general practice databases for research, demonstrates how MIQUEST software can be a useful tool in retrieving data from general practice databases, and indicates how the completeness of data recording permitted further analysis for the purposes of our study.

Data Collection↗
PubMed2001

Electronic collection of health-related quality of life data: validity, time benefits, and patient preference.

This study sought to validate World Wide Web-compliant software tools used to collect health-related quality of life (HRQOL) data, relative to pencil-and-paper collection. The RAND-36 general health survey and the Seattle Angina questionnaire (SAQ), a disease-specific functional status measure for patients with coronary artery disease, were each administered in paper and electronic format to 55 consecutive patients visiting the cardiology outpatient clinic of a public hospital. All eight sub-scale scores of the RAND-36 (interclass correlation coefficient range = 0.54-0.75, p < 0.01) and all five domains of the SAQ (interclass correlation coefficient range = 0.84-0.90, p < 0.01) collected using the software were significantly correlated with those collected using the paper version of questionnaires. Computer literacy, educational level, age, sex, and race were not significantly associated with the ability to successfully complete the computer-assisted questionnaire. Eighty-two percent of patients preferred the computer-assisted administration to paper, and 89% reported that they would feel comfortable using the software in the future without any technical assistance. This pilot study suggests that HRQOL measures can be reliably collected using software operating over the World Wide Web. Data collected in this manner are valid and of comparable quality to self-reported, HRQOL data obtained via paper survey.

Adult↗
PubMed1999

A software implementation for detailed volume conductor modelling in electrophysiology using finite difference method.

There is an evolving need for new information available by employing patient tailored anatomically accurate computer models of the electrical properties of the human body. Because construction of a computer model can be difficult and laborious to perform sufficiently well, devised models have varied greatly in the level of anatomical accuracy incorporated in them. This has restricted the validity of conducted simulations. In the present study, a versatile software package was developed to transform anatomic voxel data into accurate finite difference method volume conductor models conveniently and in a short time. The package includes components for model construction, simulation, visualisation and detailed analysis of simulation output based on volume conductor theory. Due to the methods developed, models can comprise more anatomical details than the prior computer models. Several models have been constructed, for example, a highly detailed 3-D anatomically accurate computer model of the human thorax as a volume conductor utilising the US National Library of Medicine's (NLM) Visible Human Man (VHM) digital anatomy data. Based on the validation runs the developed software package is readily applicable in analysis of a wide range of bioelectric field problems.

Body Composition↗
PubMed2006

Detection of hypopharyngeal squamous cell carcinoma using serum proteomics.

CONCLUSIONS: The combination of surface-enhanced laser desorption/ionization (SELDI) with bioinformatics tools could help find serum proteome biomarkers and establish a predictive model for early detection of hypopharyngeal squamous cell carcinoma (HSCC). OBJECTIVES: Proteomic profiling of serum using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) is an emerging technique to identify new biomarkers in biological fluids and to establish clinically useful diagnostic computational models. We used it to find new potential biomarkers and to establish a predictive model for early detection of HSCC. MATERIALS AND METHODS: One hundred serum samples including 48 from HSCC patients and 52 from normal controls which were divided into a training set and a blind testing set were treated on WCX2 and IMAC3 protein chip, and serum protein or peptide patterns were detected by SELDI-TOF-MS. The data of spectra were analyzed by Biomarker Wizard software to screen serum proteome biomarkers of HSCC. A decision tree classification algorithm and blind validation were determined by Biomarker Pattern Software (BPS). RESULTS: Ranging from 2 to 30 kDa, 45 potential biomarkers could differentiate HSCC patients from normal controls (p < 0.05). Among them four candidate protein peaks with m/z values of 7796, 4216, 5927, and 5361Da were selected to establish a predictive model by BPS with sensitivity of 94% and specificity of 89%. A sensitivity of 92% and specificity of 82% were validated in the blind testing set.

Adult↗
PubMed1988

Laboratory Information Management Systems--part II. Implementation.

In this, the second of two articles on Laboratory Information Management Systems (LIMS), the stages of the acquisition of a system are discussed. First, the laboratory automation strategy is developed leading to the writing of the requirements specification sent to prospective suppliers. The next step, in conjunction with the chosen supplier, is to write the functional and systems specifications from which the LIMS will be tailored. Once installed the LIMS must be validated and in the event of hardware or software changes, should undergo partial or full re-validation. The education and training of users, and operational considerations are presented before concluding with possible developments of LIMS in the future.

Journal Article↗
PubMed1993

Protocols for selection of cardiac radionuclide studies for use as a data base of normal studies and typical patterns of diseases. COST B2 Working Group II, in association with relevant working/task groups of the European Association of Nuclear Medicine and the European Society of Cardiology.

A data base of clinical studies is required for quality assurance of software used for analysis of radionuclide cardiac imaging procedures. Studies used must be rigorously validated in terms of both the clinical condition of the patient undergoing the procedure and the imaging protocol used. Selection protocols for the creation of a software phantom data base of normal studies and three typical patterns of cardiac disease--recent transmural myocardial infarction, isolated myocardial ischaemia and dilated cardiomyopathy--have been developed by the Cardiac Working Group of the European COST B2 project in association with the Cardiac Task Group of the European Association of Nuclear Medicine and the Working Group on Nuclear Cardiology of the European Society of Cardiology. These protocols include criteria for the interpretation of qualitative and quantitative non-radionuclide data. Compliance of the clinical data with the selection criteria will have to pass scrutiny by an international team for each study used as a software phantom. The radionuclide studies encompass stress and rest myocardial perfusion studies (planar and single photon emission tomography) using thallium-201 and technetium-99m methoxyisobutylisonitrile and rest gated blood pool studies. Methods for acquisition of data are defined for each type of study and for each individual study a portfolio of all clinical data is established. A pilot study is required to investigate the problems and logistics of distributing clinical radionuclide studies between a range of computers and institutes, and to ascertain the procedures necessary for analytical comparison of the results obtained.

Computer Communication Networks↗
PubMed2005

[Diagnostic application of serum protein pattern and artificial neural network software in breast cancer].

BACKGROUND & OBJECTIVE: The progress in proteomics provides a novel platform for early diagnosis of cancer, and screening for new tumor biomarkers. This study was designed to develop and evaluate a diagnostic model of breast cancer with surface enhanced laser desorption/ionization-time of flight-mass spectrometry (SELDI-TOF-MS) ProteinChip array technology and artificial neural network software. METHODS: SELDI-TOF-MS ProteinChip was used to detect serum protein patterns of 49 patients with breast cancer, and 33 healthy women. Diagnostic model was developed, and validated using artificial neural network software. RESULTS: An intact diagnostic model from all 253 discrepant protein peaks, and a terse model from the top-scored 4 peaks were built. The diagnostic sensitivity, and specificity of the intact model were 83.33% (15/18), and 88.89% (8/9)u the detection rates of breast cancer of stage I, and stage II-IV using the intact model were 90.00% (9/10), and 75.00% (6/8). The diagnostic sensitivity, and specificity of the terse model were 76.47% (13/17), and 90.00% (9/10)u the detection rates of breast cancer of stage I, and stage II-IV using the terse model were 100.00% (3/3), and 71.43% (10/14). The diagnostic values of these 2 models were similar (P>0.05). Their diagnostic abilities to breast cancer of stage I were not worse than those to breast cancer of stage II-IV (P>0.05). CONCLUSION: High sensitivity and specificity achieved by this method show great potential for early diagnosis of breast cancer, and screening for new tumor biomarkers.

Adult↗
PubMed2005

An in-vitro and in-vivo methodology study of alveolar bone measurement using extra-oral radiographic alignment apparatus, Image Pro-Plus software and a subtraction programme.

OBJECTIVES: (a) To validate a method for acquiring reproducible radiographic images and repeatable measurements of digital images. (b) To investigate the clinical and radiographic changes following periodontal surgery and in a periodontally healthy control group. METHODS: In-vitro study. Sixteen dried human skulls had replicate intra-oral radiographs taken using an extra-oral alignment apparatus under simulated clinical conditions, and measurements were made on the images using Image Pro-Plus analysis software. In-vivo study. Seven subjects, aged 38-63 years with chronic periodontitis, were treated using replaced flap surgery. Nine patients with healthy periodontal tissues were recruited as a control group. Clinical measurements and radiographs were taken pre-surgery and 6 months afterwards, and at the same interval for untreated healthy controls using the alignment apparatus. Radiographs were analysed using Image Pro-Plus and subtraction radiography. RESULTS: Radiographs had a high degree of reliability (ICC 0.98-0.99) for the in-vitro study and intra-operator repeatability of measurements was high (ICC 0.65-0.99) for the in-vivo study. Over this interval there were both significant clinical improvements and in bone gain within infra-bony defects on radiographs. Subtracted images showed that out of 17 surgically treated sites, 13 showed evidence of bone gain, one showed no change, two showed bone loss and one could not be interpreted due to poor alignment. Overall there were no significant clinical or radiographic changes in the control group. CONCLUSIONS: Radiographic images were highly reproducible. Measurements had a high degree of repeatability. The methods used allowed accurate quantitative and qualitative measurement of change in alveolar bone. This technique would allow accurate measurement of any changes in alveolar bone levels in patients with periodontal disease.

Adult↗
PubMed2006

In vitro experiments and numerical simulations of airflow in realistic nasal airway geometry.

Pressure-flow relationships measured in human plastinated specimen of both nasal cavities and maxillary sinuses were compared to those obtained by numerical airflow simulations in a numerical three-dimensional reconstruction issued from CT scans of the plastinated specimen. For experiments, flow rates up to 1,500 ml/s were tested using three different gases: HeO(2), Air, and SF(6). Numerical inspiratory airflow simulations were performed for flow rates up to 353 ml/s in both the nostrils using a finite-volume-based method under steady-state conditions with CFD software using a laminar model. The good agreement between measured and numerically computed total pressure drops observed up to a flow rate of 250 ml/s is an important step to validate the ability of CFD software to describe flow in a physiologically realistic binasal model. The major total pressure drop was localized in the nasal valve region. Airflow was found to be predominant in the inferior median part of nasal cavities. Two main vortices were observed downstream from the nasal valve and toward the olfactory region. In the future, CFD software will be a useful tool for the clinician by providing a better understanding of the complexity of three-dimensional breathing flow in the nasal cavities allowing more appropriate management of the patient's symptoms.

Computer Simulation↗
PubMed2006

Psychological collectivism: a measurement validation and linkage to group member performance.

The 3 studies presented here introduce a new measure of the individual-difference form of collectivism. Psychological collectivism is conceptualized as a multidimensional construct with the following 5 facets: preference for in-groups, reliance on in-groups, concern for in-groups, acceptance of in-group norms, and prioritization of in-group goals. Study 1 developed and tested the new measure in a sample of consultants. Study 2 cross-validated the measure using an alumni sample of a Southeastern university, assessing its convergent validity with other collectivism measures. Study 3 linked scores on the measure to 4 dimensions of group member performance (task performance, citizenship behavior, counterproductive behavior, and withdrawal behavior) in a computer software firm and assessed discriminant validity using the Big Five. The results of the studies support the construct validity of the measure and illustrate the potential value of collectivism as a predictor of group member performance.

Adult↗
PubMed2000

Quantification of posterior capsular opacification in digital images after cataract surgery.

PURPOSE: To describe a software program developed to provide an objective assessment of the amount of posterior capsular opacification (PCO) in high-resolution digital images of the posterior capsule after cataract surgery. METHODS: Images are analyzed by a set protocol of defining the area of the posterior capsule, removing the Purkinje light reflexes by intensity segmentation, contrast enhancement, filtering to enhance low-density PCO, and variance analysis using a co-occurrence matrix to assess texture. The accuracy of the system was tested for validity and repeatability. RESULTS: The software developed has been demonstrated to be an objective method of quantifying PCO. In validation tests, the image analysis-derived measure of PCO showed good agreement with clinically derived measures of PCO. Clinicians assessed PCO on a computer screen image and also under slit lamp examination (Pearson correlation coefficient for both methods >0.92). The entire acquisition and analysis system was demonstrated to have a confidence limit for 2 SDs of 9.8% for group data. CONCLUSIONS: This system is capable of producing an accurate and reproducible measure of PCO that is relevant to assessing techniques of PCO prevention.

Aged↗
PubMed1999

Quantitative analysis of synovial membrane inflammation: a comparison between automated and conventional microscopic measurements.

OBJECTIVE: The objective of this study was to quantify selected features of chronic synovial tissue inflammation by computerised image analysis and to validate the results by comparison with conventional microscopic measurements. METHODS: Synovial biopsy samples were obtained from the knee joints of patients with chronic arthritis and prepared for immunohistochemical analysis using standard techniques. Following the development of special software, four parameters of chronic synovial inflammation were evaluated: intimal layer thickness, CD3+ cell infiltration, CD8+ cell infiltration and vascularity. Intimal layer thickness was expressed in microns. The intensity of CD3+ and CD8+ cell infiltration was expressed as the percentage area of the tissue section occupied by positively stained cells. Vascularity was expressed as the percentage area occupied by blood vessels. Conventional quantitative microscopic analysis was also undertaken and the results from both methods compared. RESULTS: Seventy eight tissue sections were selected for study. Measurements of intimal layer thickness by both techniques correlated strongly: r = 0.85, p = 0.0006. Measurements of CD8+ cell infiltration, usually widely dispersed, also correlated well: r = 0.64, p = 0.005. Measurements of CD3+ cell infiltration, often densely aggregated, correlated less well: r = 0.55, p = 0.02. Measurements of vascularity demonstrated no statistically significant correlation: r = 0.41, p = 0.07. Proficiency in the use of computerised image analysis was readily acquired. CONCLUSION: Computerised image analysis was successfully applied to the measurement of some features of synovial tissue inflammation. Further software development is required to validate measurement of blood vessels of variable size.

Arthritis↗