SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) of the Lumisys ACR-2000 desktop computed radiography (CR) reader were measured and compared to equivalent measurements acquired from a Fuji AC-3 CR system. The one-dimensional (1D) MTF was measured from an image of a sharp edge and the 1D NPS was derived from a 2D NPS measured from a uniform field exposure. The energy dependent ideal input signal to noise ratio of the incident x-ray beams was estimated using published x-ray spectra and attenuation coefficients. Measurements were acquired using Agfa, Fuji, and Kodak storage phosphor plates and it was concluded that use of the Fuji plates resulted in the highest system DQE for the ACR-2000. The DQE was measured using exposures of 0.10, 1.0, and 10.0 mR from 70 and 120 kVp x-ray beams filtered with aluminum. The DQE of the Lumisys ACR-2000 was lower than that of the Fuji AC-3.
A method for intraoperative calibration of the Patil stereotactic system is described. After adjusting the z and y coordinates, a marker is placed in the pivot block and a CT scan is obtained. The presence of the marker in the indicator block on the same horizontal line as the target, on the image of the target, would indicate that the y and z coordinates adjustments are accurate. After the arc is attached with the x coordinate adjusted, a CT scan is obtained with the arc vertical and the probe holder at zero angle (from the vertical) position. The presence of the middle of the probe holder in the same vertical line as the target would indicate accurate x coordinate adjustment. This technique, which can be applied also to other stereotactic systems, allows the surgeon to check not only the accuracy of the system but also the accuracy of the procedure prior to inserting the probe into the brain.
Explore the source record for details and available documents.
There has been considerable discussion of the nature and scope of information that purchasers and providers must acquire and use in the post-review NHS. Somewhat surprisingly, this has not been complemented by discussion of the potential for computer systems to support information management. This in spite of the publication of the NHS Information Management and Technology Strategy, which seems set to shape the way in which purchasers and providers manage data into the next century, and expenditure on computer systems which will be in the order of hundreds of millions of pounds over the next few years. Discusses some of the key challenges involved in implementing an IT infrastructure across the NHS, and identifies five issues which will substantially determine the success of the strategy.
The organization of a central clinical chemistry laboratory of a university hospital, which in 1992 analyzed 880,000 results, is presented. Automation with midsize selective analyzers, which run in parallel and are able to do positive sample identification on the primary bar-coded tubes, in connection with a laboratory computer system and a central hospital computer allowed for reliable and timely obtainment of results. The output of the results is made on laser printers in the medical wards, thus alleviating the pneumatic sample transport systems. Assessment of the turnaround time show that it can be kept below one hour. Such a setup without sorting out emergency demands allows a simplified sample flow. Thus, there is no need for a laboratory to make "stat" requests.
A new method for elucidating the process of abdominal aortic aneurysm enlargement is presented herein. First, 3-dimensional (3-D) reconstructed images were used to precisely evaluate the size of an aneurysm, after which reconstruction and a volume analysis of images were performed with a personal computer system using serial computed tomographic films. The evolution of an aneurysm was examined by the detailed reconstruction, and an estimation of size was achieved by accurately measuring the figure reconstructed from the angle perpendicular to the axis of the contour. In quantifying the enlargement of an aneurysm, an exact evaluation of volume changes and morphological changes can be performed using the 3-D reconstruction method from the film series obtained at follow-up studies. The volume analysis proved especially useful for evaluating the axial expansion of aneurysms with stable maximum diameters.
Reconstruction of phylogenetic trees for very large datasets is a known example of a computationally hard problem. In this paper, we present a parallel computing model for the widely used Multiple Instruction Multiple Data (MIMD) architecture. Following the idea of divide-and-conquer, our model adapts the recursive-DCM3 decomposition method [Roshan, U., Moret, B.M.E., Williams, T.L., Warnow, T, 2004a. Performance of suptertree methods on various dataset decompositions. In: Binida-Emonds, O.R.P. (Eds.), Phylogenetic Supertrees: Combining Information to Reveal the Tree of Life, vol. 3 of Computational Biology, Kluwer Academics, pp. 301-328; Roshan, U., Moret, B.M.E., Williams, T.L., Warnow, T., 2004b. Rec-I-DCM3: A Fast Algorithmic Technique for reconstructing large phylogenetic trees, Proceedings of the IEEE Computational Systems Bioinformatics Conference (ICSB)] to divide datasets into smaller subproblems. It distributes computation load over multiple processors so that each processor constructs subtrees on each subproblem within a batch in parallel. It finally collects the resulting trees and merges them into a supertree. The proposed model is flexible as far as methods for dividing and merging datasets are concerned. We show that our method greatly reduces the computational time of the sequential version of the program. As a case study, our parallel approach only takes 22.1h on four processors to outperform the best score to date (Found at 123.7h by the Rec-I-DCM3 program [Roshan, U., Moret, B.M.E., Williams, T.L., Warnow, T, 2004a. Performance of suptertree methods on various dataset decompositions. In: Binida-Emonds, O.R.P. (Eds.), Phylogenetic Supertrees: Combining Information to Reveal the Tree of Life, vol. 3 of Computational Biology, Kluwer Academics, pp. 301-328; Roshan, U., Moret, B.M.E., Williams, T.L., Warnow, T., 2004b. Rec-I-DCM3: A Fast Algorithmic Technique for reconstructing large phylogenetic trees, Proceedings of the IEEE Computational Systems Bioinformatics Conference (ICSB)] on one dataset. Developed with the standard message-passing library, MPI, the program can be recompiled and run on any MIMD systems.
Cardiovascular nuclear medicine encompasses a variety of clinical procedures. Some of these procedures place demands on the imaging and data processing equipment that far exceeds those associated with other nuclear medicine procedures. This paper is devoted to an evaluation of the imaging and data processing requirements for two of the more demanding studies in cardiovascular nuclear medicine--first transit and gated equilibrium measurement of ventricular function. Imaging instrumentation and collimation, computer system hardware, and computer acquisition and analysis software are each treated as they apply to these procedures.
AIMS: To discuss the potential use of data mining and knowledge discovery in databases for detection of adverse drug events (ADE) in pharmacovigilance. METHODS: A literature search was conducted to identify articles, which contained details of data mining, signal generation or knowledge discovery in relation to adverse drug reactions or pharmacovigilance in medical databases. RESULTS: ADEs are common and result in significant mortality, and despite existing systems drugs have been withdrawn due to ADEs many years after licensing. Knowledge discovery in databases (KDD) is a technique which may be used to detect potential ADEs more efficiently. KDD involves the selection of data variables and databases, data preprocessing, data mining and data interpretation and utilization. Data mining encompasses a number of statistical techniques including cluster analysis, link analysis, deviation detection and disproportionality assessment which can be utilized to determine the presence of and to assess the strength of ADE signals. Currently the only data mining methods to be used in pharmacovigilance are those of disproportionality, such as the Proportional Reporting Ratio and Information Component, which have been used to analyse the UK Yellow Card Scheme spontaneous reporting database and the WHO Uppsala Monitoring Centre database. The association of pericarditis with practolol but not with other beta-blockers, the association of captopril and other angiotensin-converting enzymes with cough, and the association of terfenadine with heart rate and rhythm disorders could be identified by mining the WHO database. CONCLUSION: In view of the importance of ADEs and the development of massive data storage systems and powerful computer systems, the use of data mining techniques in knowledge discovery in medical databases is likely to be of increasing importance in the process of pharmacovigilance as they are likely to be able to detect signals earlier than using current methods.
Despite extensive research and a multitude of computer systems, there is no viable computerized system that is even remotely capable of approaching the skill of an expert human physician. Minor obstacles in the design of a practical system include imprecise medical terminology, the use of nonindependent clinical parameters, incorrect or inaccurate information supplied to the computer, and static representation of a patient's medical history. Major problems that go beyond computer manipulation of data include the requirement for a massive data base, representation of medical knowledge in general rather than specific terms, and physician fallibility in the design of a computer system.
There was a 70 per cent response to a mail questionnaire to a 1:3 sample of Australian Dental Association members in private practices (n = 1931). Computers were used by 37 per cent of practices. Main computer applications used were for: accounting (84%); patient billing (80%); word processing (79%); and patient recall (61%). External bureau services were used by 4 per cent of practices with most computers being in-house (single terminal 66%; multiple terminal 33%). The more dentists in a practice, the more likely was a computer to be used. Principal users were secretary/receptionists. Service and software were the most important factors in choice of computer system. Many practice computer users (67%) also had a Personal Computer at home compared with only 36 per cent of the non-users. Many respondents indicated the need for continuing education in computers (67% users; 61% non-users). More than half of the non-users indicated future use of computers for accounting, billing and recall. There has been a considerable increase in the use of computers in private practice (37%) since the Australian Dental Association Dental Practice Survey in 1983/84 (9%).
AIM: To develop a system for routine monitoring of visual outcome after cataract surgery. METHODS: Staff from eight eye centres in Asia and Africa defined the data collection form and report formats to be used for monitoring visual outcome after cataract surgery. Several operational research questions were raised and methods developed to address them. The system was field tested for 6 months and the operational studies undertaken. The system was finalised based upon the experience gained. FINDINGS: Two different systems for data collection were developed: a manual paper tally system and a computer system (cataract surgery record forms (CSRF)). Both systems report on operative complications; the proportion with good outcome (can see 6/18) and poor outcome (cannot see 6/60); and causes of poor outcome. Data are collected at discharge and at specified time intervals at follow up. Both systems were well accepted. CONCLUSION: The major problem in field testing was data entry errors in centres using the computerised system. Routine monitoring of cataract outcome should be used by individual surgeons or centres to follow trends in their own results over time, and not to compare surgeons, in an atmosphere of trust and support. Visual acuity at discharge, which can readily be collected on all patients, can be used providing it is appreciated that the final results will be much better. Rapid feedback of results can enhance the consciousness of the eye surgeons to causes of poor outcome. Accuracy in data entry and an efficient flow of record forms are essential.
The accuracy of a system for reconstructing a three dimensional image of the left ventricle from randomly recorded multiple short axis images was tested by comparing the calculated left ventricular volume with the directly measured left ventricular volume in 11 excised porcine hearts. The system comprised a real time phased array sector scanner, a transducer locating system, and a computer system for digitising outlines of the left ventricle, displaying the reconstruction image, and calculating the left ventricular volume. The reconstructed image was similar to the real image and the calculated left ventricular volume showed a high correlation with the directly measured left ventricular volume. This method was accurate in vitro and is expected to be available for clinical measurement of left ventricular volume.
Explore the source record for details and available documents.
We describe the improvements created by successful implementation of a laboratory information system for a multi-institutional integrated delivery system, including an analysis of the financial results. Conditions at the outset of the project, methods of management and project design, selected aspects of services redesign and consolidation, integration of services among the sites and their effects on laboratory staff and productivity are illustrated. A method for and example of measuring the financial outcomes in the sense of quantifiable improvements in operating expenses and new revenue for a whole health system clinical laboratory computer system are discussed. In this health system, the measurable financial improvements facilitated by an information system were the ability to control operating expenses and to grow the hospital laboratory network through the development of an outreach program. With organizational commitment to process innovation and improvement, using team processes and customer-driven decision-making criteria, the financial performance of our consolidated laboratory network was enhanced substantially. A fully implemented laboratory information system is considered the major enabler of positive change when combined with a genuine commitment from all levels of staff and leadership. Over time, this system's financial return is several times that of the information system investment.
Explore the source record for details and available documents.