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At least 1,135 records · Page 63Linked to original sources
PubMed1997

Teleradiology in urology: comparison of digital image quality with original radiographic films to detect urinary calculi.

PURPOSE: Teleradiology systems are now being evaluated as a mechanism to provide rapid, accurate and cost-effective diagnostic radiographs to off-site physicians. Little data are available on the role and safety of teleradiology in urology. To address these issues a personal computer based system was developed to assess the diagnostic accuracy and ease of use of transmitted digital images when evaluating for urinary calculi. MATERIALS AND METHODS: A total of 100 plain abdominal scout films from excretory urograms performed during acute urological referrals was digitized on a laser scanner. The 10 megabyte files were transferred over public telephone lines and written to compact disks. The images were viewed on a 1280 x 1640 resolution monitor using "Imager-3D" software run on a 133 MHz. pentium personal computer with 32 megabytes of random access memory. Two faculty urologists and 2 urology fellows each looked at 50 original radiographs and 50 digital images. Diagnostic interpretations of the presence and location of calculi were recorded, and confidence in the diagnosis, assessment of image quality and diagnostic difficulty were scored using a numerical scale. RESULTS: The accuracy for all readers was 86.5% for plain radiographs and 81.5% for digital images (p >0.2). There was no statistical difference between faculty and fellows. Diagnostic accuracy did not differ between plain films and screen images when the results were assessed with respect to image quality, diagnostic difficulty or the reader confidence in the diagnosis (p >0.1). Compared to plain films, more screen images were classified as lower image quality (60 versus 40%) and the diagnostic confidence was lower (low and medium grade 50 versus 35%), although this did not interfere with diagnostic accuracy. CONCLUSIONS: These data imply that a high quality affordable teleradiology system is effective and accurate compared to plain films for assessing urinary calculi.

Humans↗
PubMed2004

High frequency monitoring of the coastal marine environment using the MAREL buoy.

The MAREL Iroise data buoy provides physico-chemical measurements acquired in surface marine water in continuous and autonomous mode. The water is pumped 1.5 m from below the surface through a sampling pipe and flows through the measuring cell located in the floating structure. Technological innovations implemented inside the measuring cell atop the buoy allow a continuous cleaning of the sensor, while injection of chloride ions into the circuit prevents biological fouling. Specific sensors for temperature, salinity, oxygen and fluorescence investigated in this paper have been evaluated to guarantee measurement precision over a 3 month period. A bi-directional link under Internet TCP-IP protocols is used for data, alarms and remote-control transmissions with the land-based data centre. Herein, we present a 29 month record for 4 parameters measured using a MAREL buoy moored in a coastal environment (Iroise Sea, Brest, France). The accuracy of the data provided by the buoy is assessed by comparison with measurements of sea water weekly sampled at the same site as part of SOMLIT (Service d'Observation du Milieu LIToral), the French network for monitoring of the coastal environment. Some particular events (impact of intensive fresh water discharges, dynamics of a fast phytoplankton bloom) are also presented, demonstrating the worth of monitoring a highly variable environment with a high frequency continuous reliable system.

Automation↗
PubMed1997

Relating formulation variables to in vitro dissolution using an artificial neural network.

The purpose of this paper was to investigate the effect of several experimental variables on the ability of a neural network to predict in vitro dissolution rate as a function of product formulation changes. Neural network software was trained with sets of hypothetical and experimental data consisting of 4-15 formulations with known in vitro drug dissolution profiles and the ability of the trained model to recognize patterns was validated against similar formations not used to train the neural network. The effect of selected variables, e.g., number of hidden-layer nodes and iterations, as well as the use of replicate or mean data on the accuracy of the predictions was investigated. The importance of optimizing the number of hidden-layer nodes and iterations was demonstrated. The prediction error increased for validation data sets that were outside the range of the training data set. Accurate predictions were obtained with as few as four formulations in the training set, provided the formulations were carefully chosen, and the number of formulation variables were small. Also, limiting the validation set to one formulation was not sufficient to validate the neural network model. Increasing the size of the training set, or replication of the input and output data, also provided more accurate predictions. The neural network accurately predicted in vitro drug release provided the neural network variables were optimized, and the training and validation data sets were appropriately selected.

Acetaminophen↗
PubMed1993

Changes in total death rate and in ischaemic heart disease death rate in interethnic South African populations, 1978-1989.

Ischaemic heart disease (IHD) in prosperous Western populations rose markedly in the 1940s, peaked between 1970 and 1975 and then fell variably--by about 50% in the USA and Australia. Undoubtedly, decreases in serum cholesterol levels, in the incidence of hypertension and in smoking frequencies are largely responsible. In South Africa, in all population groups other than blacks, IHD rates rose analogously, with Asians and whites attaining very high rates. However, from 1978 to 1989, the total death rate among white males (per 100,000 world population) fell from 1,002 to 631 (37%), and the IHD mortality rate from 312 to 139 (56%). Rates for Asians were 1,306-1,130 (14%) and 355-226 (36%), respectively, and for coloureds 1,691 to 1,392 (18%) and 171 to 110 (36%). For blacks, the total mortality rate remained unchanged; IHD rates were low, but these data are unreliable. Percentage falls in the IHD rate exceed those in the total death rate, especially among whites, indicating true decreases in IHD rate. Understandably, the accuracy of the data, as with such data overseas, is questionable. Local falls are none the less in line with those noted in Western countries. Rates for whites remain very high, and are even higher for Asians. While knowledge of the reasons for the rises and falls in IHD rates remains incomplete, whites have none the less taken some preventive action, although Asians and coloureds apparently little.

Adult↗
PubMed1998

Towards improving the accuracy of the clinical database: allowing outpatients to review their computerized data.

We developed an application that allowed patients coming to the clinic to review on a paper form their computerized health maintenance, medication, and allergy data. The patient could edit the paper form and the physician then could enter the new data into the database. We implemented the system in 4 clinics (17 MDs) To evaluate the system, we reviewed 80 forms from one physician's patients to determine how often patients provided new data. We also sent questionnaires to the physicians asking for their estimates of how often there was new data and for their impression of the system. We interviewed secretaries in the clinics about logistical issues. Of the 80 forms, 29 (36%) had new data; 28% had new health maintenance data and 19% had new medication data. The 7 physicians who responded to the questionnaire estimated that new health maintenance data were present on 22% of the forms. The physicians who responded to the questionnaire felt the system was useful. The secretaries said that managing the paper flow in the clinic was often unwieldy and in some clinics, the system has been abandoned or is used intermittently. Having patients review their data is one avenue to improving the accuracy of computerized records.

Adult↗
PubMed1997

The influence of psychological and social factors on accuracy of self-reported blood pressure.

The data reported here document levels of accuracy in reports of blood pressure and identify correlates of inaccurate reporting. The data come from a long-term follow-up of a cohort of African-American women who registered for antepartum care between September, 1967 and June, 1969. At the follow-up interview, these women were asked whether they had ever received a diagnosis of hypertension from a physician. The self-reports of hypertension were compared with information contained in the medical records of these women. Twenty-five percent reported having high blood pressure but 53% of these reports were unconfirmed by their medical records (overall misreporting rates was 15.9% with 2.5% underreporting and 13.4% overreporting). The factors related to misreporting included a psychiatric diagnosis (based on the Diagnostic Interview Schedule) of major depressive disorder or drug and/or alcohol abuse and a small social network. The conjunction of these three variables significantly affected accuracy of reporting (100% misreporting with all three variables). These results suggest that, using currently standard methodology, there is an unreliable subpopulation of respondents in health surveys that may require the collection of data on health status from a second source to confirm data from self-reported health measures.

Adult↗
PubMed2005

The use of injury surveillance databases to identify emerging injury hazards.

Among the many valuable uses of injury surveillance is the potential to alert health authorities and societies in general to emerging injury trends, facilitating earlier development of prevention measures. Other than road safety, to date, few attempts to forecast injury data have been made, although forecasts have been made of other public health issues. This may in part be due to the complex pattern of variance displayed by injury data. The profile of many injury types displays seasonality and diurnal variance, as well as stochastic variance. The authors undertook development of a simple model to forecast injury into the near term. In recognition of the large numbers of possible predictions, the variable nature of injury profiles and the diversity of dependent variables, it became apparent that manual forecasting was impractical. Therefore, it was decided to evaluate a commercially available forecasting software package for prediction accuracy against actual data for a set of predictions. Injury data for a 4-year period (1996 to 1999) were extracted from the Victorian Emergency Minimum Dataset and were used to develop forecasts for the year 2000, for which data was also held. The forecasts for 2000 were compared to the actual data for 2000 by independent t-tests, and the standard errors of the predictions were modelled by stepwise hierarchical multiple regression using the independent variables of the standard deviation, seasonality, mean monthly frequency and slope of the base data (R = 0.93, R(2) = 0.86, F(3, 27) = 55.2, p < 0.0001). Significant contributions to the model included the SD (beta = 1.60, p < 0.001), mean monthly frequency (beta = -0.72, p < 0.002), and the seasonality of the data (beta = 0.16, p < 0.02). It was concluded that injury data could be reliably forecast and that commercial software was adequate for the task. Variance in the data was found to be the most important determinant of prediction accuracy. Importantly, automated forecasting may provide a vehicle for identifying emerging trends.

Accident Prevention↗
PubMed1997

Effect of computerized requisition of radiology examinations on the transmission of clinical information.

RATIONALE AND OBJECTIVES: The authors developed a method to evaluate the availability and accuracy of clinical data proffered by clinicians when ordering radiologic examinations with a computer order-entry system. METHODS: Two thousand consecutive clinical indications for a spectrum of pediatric imaging studies were scrutinized for accuracy by means of computerized chart review, verbal communication with clinical attending staff, and reference to surgical and laboratory results. The indications were classified as appropriate, incorrect, misleading, or incomplete. RESULTS: Of the 2,000 stated indications, 1,464 (73%) provided a reasonable, if minimal, amount of clinical information; however, in 376 (19%) cases the diagnosis or proximate indication was incorrect, in 108 (5%) cases the data were incomplete, and in 52 (3%) cases the information was misleading. CONCLUSION: Computer order-entry systems can improve the transmission of clinical information but they allow misinformation to be provided.

Hospital Information Systems↗
PubMed1986

A practical evaluation of accuracy with the standard deviation index (SDI) chart method. Second report. Report covering the period from April 1980 to March 1983.

To evaluate the accuracy of laboratory data for 18 items determined with an Technicon SMAC (Sequential Multiple Analyzer Computer), the SDI chart method was used in investigating the data according to five kinds of control survey programs from April 1980 to March 1983. The results can be summarized as follows: Inorganic phosphorus showed a gradual downward shift, arriving at the minus side of SDI in all control surveys. Potassium showed a particularly large fluctuation as was the case in the previous evaluation. The other items were relatively stable (i.e., showed less fluctuation), although many of them showed an upward shift. Some of the control survey programs yielded biased evaluation results. Thus, the SDI chart method proved to allow, as one of the external quality control techniques, observation of long-term, slight changes without necessitating any complicated calculation. Furthermore, it was confirmed that this is a practically useful method of accuracy evaluation because it allows overall evaluation of the data from various control survey programs on the same graph.

Alkaline Phosphatase↗
PubMed2005

Accuracy of fetal echocardiography in the routine detection of congenital heart disease among unselected and low risk populations: a systematic review.

OBJECTIVE: To determine among unselected and low risk populations the accuracy with which fetal echocardiography during the second trimester detects congenital heart disease. DESIGN: A systematic review of studies that assess the accuracy of fetal echocardiography. SETTING: District General Hospital and Tertiary referral centres. POPULATION: Women during the second trimester attending for ultrasound assessment. METHODS: General bibliographic databases (e.g. MEDLINE, EMBASE) and specialist computerised databases (e.g. Cochrane Library, National Research Register), grey literature, manual searching of reference lists of primary and review articles and personal contact with experts were used to identify studies. Studies were included if fetal echocardiography among unselected or low risk pregnant women was compared against a postnatal reference standard. Data were extracted on quality, study design and characteristics, and accuracy data to construct 2 x 2 tables. Data were synthesised qualitatively, and sensitivity and specificity with 95% confidence intervals were calculated. MAIN OUTCOME MEASURE: Sensitivity and specificity. RESULTS: Five primary studies met the inclusion criteria and comprised 60,901 subjects. One study assessed the accuracy of fetal echocardiography among an unselected population and four studies among low risk populations. All eligible studies found that fetal echocardiography helped to correctly diagnose normal fetus among unselected and low risk populations. Correct diagnosis of babies for congenital heart defects was higher among the unselected population (85%) than among the low risk populations (range from 35% to 86%); however, the potential for ascertainment bias and the choice of reference standard limits the validity of this finding. The variation in sensitivity across studies was not explainable by clinical factors such as scanning regime, operator skill and equipment. CONCLUSIONS: The evidence from this review about the accuracy of fetal echocardiography does not lend support to its routine use among unselected and low risk populations during the second trimester to detect congenital heart disease.

Echocardiography↗
PubMed1999

Performance, patient acceptance, appropriateness of indications and potential influence on outcome of EUS: a prospective study in 397 consecutive patients.

BACKGROUND: Although there is a large body of data on the accuracy of endoscopic ultrasonography (EUS) in the diagnosis and staging of various gastroenterological disorders, little has been published on the influence of EUS in the management of patients. Data on the performance of EUS and patient acceptance are also sparse. METHODS: During a 10-month period, all consecutive EUS examinations were categorized by the examiner according to the appropriateness of the indications. Prior examinations, performance of EUS (duration, premedication, complications), and patient acceptance (assessed using a questionnaire by an independent investigator) were recorded. A mean of 2 months after the procedure, referring physicians were asked about the extent to which the EUS results had influenced their further diagnostic and therapeutic approach. RESULTS: A total of 397 patients were included; they were referred for EUS after a mean of 1. 8 specific tests had been performed. The appropriateness of the indications for EUS was categorized as "classic," "useful," and "potentially useful" (categories 1 to 3) in 81% of cases. The referring physicians replied that EUS had provided useful additional information in 55% of cases; the EUS findings prompted further tests in 22% and made further examinations unnecessary in 30%. A change in therapy was believed to be directly due to EUS in only 6% of cases. The duration of the EUS examinations ranged from a mean of 8.1 minutes (esophageal indications) to 18.9 minutes (biliary indications). There were no complications. In patients who were able to remember the EUS examination (42%), 90% found it tolerable, and 83% of all the patients interviewed were willing to have the examination repeated with the same level of sedation. CONCLUSIONS: EUS is a safe examination that can be carried out within a reasonable time frame by experienced examiners and without significant patient discomfort when performed under conscious sedation. With regard to patient management, EUS mainly influences further diagnostic tests.

Adolescent↗
PubMed1987

Interviewing older adults: the accuracy of factual information.

Using data from a probability sample of adults in a metropolitan area, the accuracy of survey measures was assessed by comparisons to administrative records, census counts, and maps. Some types of information, including birth date and make and year of car, were reported accurately by most respondents, whereas frequent errors were detected for other types of information, including voting behavior, house value, and characteristics of neighbors. Comparisons were made with respect to the relative accuracy of the reports of respondents in three age groups: younger than 60, 60 through 69, and 70 or older. For many measures, no age differences were detected, and for those where age differences were observed, the older respondents were sometimes more accurate than the younger respondents. The potential consequences of measurement error are serious. Evidence to date, however, does not indicate consistently that these problems are any more serious for older respondents than for any other age group.

Age Factors↗
PubMedDate not supplied

Evaluation of CT techniques for reducing artifacts in the presence of metallic orthopedic implants.

Metallic intramedullary orthopedic implants generate artifacts that can markedly degrade transaxial CT images. The artifacts, typically seen as starburst streaking, result primarily from reconstructions involving missing projection data. Two approaches are clinically available to reduce the artifacts around orthopedic implants. These are (a) the imaging of implants with lower attenuation coefficients or smaller path lengths (less attenuating objects) and (b) the planar reformatting of image data. The sizing accuracy of these two approaches was quantified using phantoms and the efficacy using cadaveric femoral specimens. Results demonstrated that metal artifacts may be reduced and accurate bony dimensional data obtained.

Evaluation Studies as Topic↗
PubMed1999

Under representation of morbidity from paediatric bicycle accidents by official statistics--a need for data collection in the accident and emergency department.

OBJECTIVES: To determine the accuracy of currently available data on bicycle related injuries in children. SETTING: A paediatric accident and emergency (A&E) department which annually treats approximately 30000 new patients under the age of 13 years. METHODS: Data on all attendances with bicycle related injuries over a four week period were compared with that currently available from police road traffic accident data (Stats 19) and the International Classification of Diseases, 10th revision, hospital discharge coding. RESULTS: Eighty six children attended the A&E department. Only two bicycle related injuries were identified from Stats 19, and 10 from hospital discharge data. CONCLUSION: Currently available official data do not give an accurate representation of the incidence of bicycle related injuries in children. If health promotion measures are to be assessed properly data collection needs to be improved.

Bicycling↗
PubMed1986

ICD-9-CM code and coding practice changes for case mix management.

Over the past several years, there has been increased interest in the quality of existing patient data for analysis purposes. Although attempts have been made to use discharge abstract data in numerous applications, e.g., hospital planning and utilization review programs, probably the greatest impact has come with the use of these data as the basis of hospital payment for patient care services. This one application has led the health care community to pay serious attention to the consistency and accuracy of patient data collection.

Abstracting and Indexing↗
PubMed1985

Clinical staging of rectal cancer. Results of a prospective continuing study.

78 patients with rectal adenocarcinoma were studied with a diagnostic protocol in order to obtain a TNM clinical stage in the preoperative period. Each patient underwent digital rectal examination, proctoscopy, double contrast barium enema, pelvic CT scan, liver ultrasound and chest x-ray. The degree of infiltration of the rectal wall by the tumor and the presence or absence of node and liver metastases were evaluated. After resection all specimens were studied by a pathologist who defined the pathologic stage. Data obtained by each diagnostic procedure were compared with the pathologic data. For each method, accuracy, specificity and sensitivity were evaluated. Each method showed an equivalent accuracy (100%) to detect infiltration of the muscularis of the rectum. Data were less accurate in identifying extraparietal tumor invasion. Accuracy was 79% for rectal examination, 74% for double contrast barium enema and 72% for pelvic CT scan. In the evaluation of lymph-node involvement, accuracy was 77%, specificity 74% and sensitivity 80%. Liver metastases were detected with 94% accuracy, 97% specificity and 50% sensitivity.

Barium Sulfate↗
PubMed1997

Prediction of posterior fossa tumor type in children by means of magnetic resonance image properties, spectroscopy, and neural networks.

Recent studies have explored characteristics of brain tumors by means of magnetic resonance spectroscopy (MRS) to increase diagnostic accuracy and improve understanding of tumor biology. In this study, a computer-based neural network was developed to combine MRS data (ratios of N-acetyl-aspartate, choline, and creatine) with 10 characteristics of tumor tissue obtained from magnetic resonance (MR) studies, as well as tumor size and the patient's age and sex, in hopes of further improving diagnostic accuracy. Data were obtained in 33 children presenting with posterior fossa tumors. The cases were analyzed by a neuroradiologist, who then predicted the tumor type from among three categories (primitive neuroectodermal tumor, astrocytoma, or ependymoma/other) based only on the data obtained via MR imaging. These predictions were compared with those made by neural networks that had analyzed different combinations of the data. The neuroradiologist correctly predicted the tumor type in 73% of the cases, whereas four neural networks using different datasets as inputs were 58 to 95% correct. The neural network that used only the three spectroscopy ratios had the least predictive ability. With the addition of data including MR imaging characteristics, age, sex, and tumor size, the network's accuracy improved to 72%, consistent with the predictions of the neuroradiologist who was using the same information. Use of only the analog data (leaving out information obtained from MR imaging), resulted in 88% accuracy. A network that used all of the data was able to identify 95% of the tumors correctly. It is concluded that a neural network provided with imaging data, spectroscopic data, and a limited amount of clinical information can predict pediatric posterior fossa tumor type with remarkable accuracy.

Astrocytoma↗
PubMed2006

Establishment of an architecture-specific experimental validation approach for finite element modeling of bone by rapid prototyping and high resolution computed tomography.

A new experimental validation method for assessing the accuracy of large-scale finite element (FE) models of bone micro-structure at the apparent and tissue level was developed. Augmented scaled bone replicas were built using rapid prototype machines based on micro-computed tomography (micro-CT) data. The geometric accuracy of the model was evaluated by comparing experimental tests with the replicas to the FE solution based on the same micro-CT data. A new version of the large-scale FE solver was developed to incorporate orthotropic material properties, hence the experimentally determined properties of the rapid prototype material were input into the FE models. The modified FE solver predicted the experimental apparent level stiffness within less than 1%, and the difference between experimental strain gauge measurements and FE-calculated surface stresses was 7% and 49% on a flat and curved surface region, respectively. While absolute error estimates of surface stresses were limited due to strain gauge errors, the relatively larger difference on the curved surface is indicative of the limitations of a hexahedron FE model for representing such geometries. Although the validation approach is applied here for hexahedron based meshes, the method is flexible for varying bone architectures and will be important for validation of future large-scale FE modeling developments that utilize techniques such as mesh smoothing and tetrahedron elements.

Bone and Bones↗