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At least 127 records · Page 7Linked to original sources
PubMed2005

Magnetic resonance imaging systems. A guide to the technology.

Magnetic resonance imaging (MRI) has become firmly established as an essential imaging tool. Two characteristics of MRI--its ability to image soft tissue and its avoidance of harmful ionizing radiation--more than compensate for the costs, complexity, safety issues, and patient discomfort associated with it. Today, MRI is the modality of choice for a number of neurological and musculoskeletal indications and is being used for more applications than ever before. In some cases, MRI is supplementing existing techniques, such as vascular and cardiac imaging, while in others it is used to image physiologic processes that are invisible to any other imaging modality. MRI scanners are growing increasingly complex. As the technology develops, capabilities that were once available only to researchers are becoming routine in clinical applications. As a result, buyers now have more decisions to make when selecting a scanner than ever before. It is no longer simply a choice of field strength or whether to opt for an open or closed system. To gain an understanding of the important factors to consider when selecting MRI equipment, it is necessary to have a good understanding of how the systems work. In this article, we describe the operating principles of MRI systems. We also describe the major components of a system and the considerations involved when implementing MR imaging. Finally, we describe the issues surrounding the higher-powered three-tesla systems that are beginning to see commercial use.

Decision Making↗
PubMed1988

Computerized analysis of resting fetal heart rate tracings.

Previous attempts to computerize the analysis of fetal heart rate (FHR) using mainframe or minicomputers were not accepted in routine clinical practice because of their complexity, cost, and lack of validation. We describe the first practical, inexpensive system integrated into a clinical protocol that analyzes and documents FHR baseline, long-term variability, and episodic events using a standard microcomputer. A comparison of computerized and manual analyses of 284 nonstress tests (NSTs) of high-risk patients revealed no significant differences in determining the number of acceleration and deceleration events and mean FHR baseline. Long-term variability and other reported data could not be compared for lack of manual techniques. The combination of standardized analysis and quantified data may improve the predictive value of the computerized NST compared with the visually analyzed NST. Other benefits include computerized archiving, data transmission by telephone, and linkage to a perinatal data base.

Diagnosis, Computer-Assisted↗
PubMed1995

[Focus on the role of ventilation and ultraviolet rays in preventing nosocomial transmission of tuberculosis in health care facilities. Groupe de travail sur la prévention de la transmission nosocomiale de la tuberculose (Direction Générale de la Santé)].

Recent episodes of nosocomial tuberculosis, sometimes due to multiresistant strains, in HIV infected patients in the USA has led to the need for new prevention measures against the transmission of Mycobacterium tuberculosis in health care facilities. Tuberculosis is transmitted in Pflügge droplets generated when contagious persons cough. After drying, the droplets become aerosolized solid particles which are rapidly dispersed by air flow within the patient's room. People exposed to the same air are thus at high risk of being contaminated. If the air pressure in the patient's room is higher than the rest of the facility, the air coming form the room may contaminate personnel and other patients elsewhere in the facility. Infecting particles can be eliminated rapidly if the room air is ventilated outdoors. If the ventilation is strong enough so that air constantly circulates from the corridor into the room, infecting particles can no longer diffuse to the rest of the ward. It is also possible to use ultraviolet C light to disinfect the air, either within the room or within the ventilation system. These two basically simple systems are the fundamental environmental and prevention measures needed to limit tuberculosis spread in health care facilities. These methods are however technically complex, costly and require constant evaluation and maintenance by specialized personnel. In addition the potential side effects of ultraviolet waves could considerably reduce their application. These environmental methods, which are complementary methods, only have a meaning if the elementary measures for preventing the transmission of tuberculosis are correctly applied.(ABSTRACT TRUNCATED AT 250 WORDS)

Cross Infection↗
PubMed1977

Measuring the cost of caring for a foster child.

The problem of determining this cost is complex. Total costs include the direct or out-of-pocket costs and indirect costs, or the value of time devoted to rearing foster children. The use of secondary data for estimating coses in local areas is recommended.

Age Factors↗
PubMed1996

[Usefulness of the visual analysis of night oximetry as a screening method in patients with suspected clinical obstructive sleep apnea syndrome].

Conventional polysomnography (CPS) is a complex, costly procedure that is not widely available, meaning that it is difficult to apply it in patients suspected of having obstructive sleep apnea syndrome (OSAS). Various procedures have therefore been proposed for screening candidates for CPS. We studied the usefulness of visual analysis of nocturnal oximetry in 96 patients suspected of having OSAS. The OSAS diagnosis was confirmed by CPS in 67 (69.8%). Oximetry was positive in 70 cases. Sixty-one patients were positive by both oximetry and CPS, while 9 and positive oximetry results and a negative CPS. We conclude that nocturnal oximetry has a 91% sensitivity and 69% specificity for OSAS, with a positive predictive value of 87% and a negative predictive value of 77%. We believe that nocturnal oximetry may be a useful way of screening for OSAS, in order to decrease the number of CPS performed on patients without the disease.

Adult↗
PubMed1998

Transferred patients--more complex and more costly?

AN-DRGs have some splits which take illness severity and complexity into account. Age is also often used as a proxy for severity of illness. The need to transfer a patient may be a marker of illness severity or complexity and therefore resource utilisation. This is supported by studies of patients transferred to intensive care units. Data on the costs and outcomes of all transferred patients should be collected; depending on the results, refinements of DRGs may be indicated.

Australia↗
PubMed2001

Telemedicine in a box: overcoming complexity and high-cost telemedicine barriers using self-contained videoconferencing units.

This report describes our experience using low-and moderate-cost videoconferencing systems for telemedicine. After determining that low-cost systems using a standard personal computer and personal computer camera were unsatisfactory, a demonstration project was carried out using a $4000 self-contained videoconferencing unit (telemedicine in a box), using eight simulated telemedicine consultation scenarios. The quality of the videoconferencing was good for all eight scenarios. All eight consultation simulations demonstrated different ways of improving patient care. Two of the major problems hindering the broad proliferation of telemedicine (high cost and high complexity) are solved by the telemedicine in a box concept. Focussing on the telemedicine in a box concept when planning a telemedicine system will improve its feasibility in the real world of health care.

Humans↗
PubMed2005

Uncle Sam wants your EHR.

It might not be as glamorous as the mission to the moon, but creating a national health care IT infrastructure could prove as complex and costly. Just how complex, how costly and how long it will take are open to debate, but nearly everyone agrees that achieving that goal should be a national priority and that Americas can-do spirit will prevail.

Computer Security↗
PubMed1997

Genetic code synonym quotas and amino acid complexity: cutting the cost of proteins?

The synonym quotas within the genetic code for the 20 common amino acids are examined in relation to the ways in which these amino acids can be marshalled into different sets on the basis of shared physico-chemical properties. This reveals which shared properties are encouraged or discouraged during the course of protein evolution by the arrangement of the code. A dominant theme is that the synonym quotas are allocated in favour of small and chemically uncomplicated residues, and to the disadvantage of large and chemically prominent ones. From amongst the various measurements that can be considered to quantitatively express aspects of amino acid residue "size and complexity" (e.g. side chain volume, bulkness and formula weight), formula weight has the highest correlation with the synonym quota for each amino acid. However, the correlation is weak. A specially derived "size/complexity" scale for the amino acids based on their relative atomic composition improved the correlation only marginally. The existence of another weak correlation between the synonym quotas and the general amino acid composition of proteins prompted an investigation of the correlations between this composition and the previously considered amino acid properties. Again, the highest correlations are with amino acid formula weight and "size/complexity", but in this instance the correlations are high enough to be truly significant. It is suggested that the biased synonym quotas in the genetic code are intended to ensure that proteins as a whole maintain a certain amino acid composition, even to the extent that the quotas include compensatory biases to counter opposing influences upon this composition caused by the processes of natural selection for protein function. It is the need for these compensatory biases that prevents a simple correlation between the quotas and measures of amino acid complexity. The final outcome, in which amino acids are deployed in functional proteins in approximate proportion to their chemical complexity may serve both as a means of minimising the negative consequences of random genetic mutation (by reducing the chance appearance of the more "disruptive" types of side chain in proteins) and as a means of ensuring the most economic use of biosynthetic resources. According to this reasoning, the code is not a "frozen accident"; it is universally appropriate because it provides the best compromise that can be achieved between biosynthetic cost and biological return in respect of the rate of protein evolution.

Amino Acids↗
PubMed1999

The relation between meal size and the time between meals: effects of cage complexity and food cost.

Certain popular models of the regulation of food intake predict a positive correlation between the size of a meal and the preceding and/or following intermeal interval. However, the reported strength of these prandial correlations has varied widely in the literature. To determine what factors may influence the strength of these relationships, we measured the timing of and amount consumed in meals of laboratory rats as a function of 1) whether they were housed in isolation or with partial access to peers or a running wheel, 2) whether they were disturbed daily or weekly for maintenance procedures, and 3) whether food was free or contingent on operant responding. We also compared two definitions of "meal" and "intermeal interval." Strong prandial correlations were found only occasionally. Caging, food cost, and maintenance frequency did not affect the size of the correlations, although these factors did influence the rats' meal patterns. We conclude the regulation of food intake cannot be explained by models relying on a regular relationship between meal size and intermeal interval.

Analysis of Variance↗
PubMed1986

On the feasibility and usefulness of physician DRGs.

In response to pressure to curb increases in Medicare physician fees, Congress authorized the Department of Health and Human Services to undertake research on the advisability and feasibility of paying physicians based on diagnosis related groups (DRGs). This report is a summary of the findings of two reports that examined DRG-based physician payment arrangements along with other methods of packaging physician services for payment. The reports imply that a DRG physician payment system could unfairly redistribute payments from physicians with genuinely more complex and costly practices to physicians with less complex and costly practices. We conclude that a physician DRG methodology might nonetheless provide a useful tool for monitoring physician practice styles.

Costs and Cost Analysis↗
PubMed2006

A general multivariate extension of Fisher's geometrical model and the distribution of mutation fitness effects across species.

The evolution of complex organisms is a puzzle for evolutionary theory because beneficial mutations should be less frequent in complex organisms, an effect termed "cost of complexity." However, little is known about how the distribution of mutation fitness effects (f(s)) varies across genomes. The main theoretical framework to address this issue is Fisher's geometric model and related phenotypic landscape models. However, it suffers from several restrictive assumptions. In this paper, we intend to show how several of these limitations may be overcome. We then propose a model of f(s) that extends Fisher's model to account for arbitrary mutational and selective interactions among n traits. We show that these interactions result in f(s) that would be predicted by a much smaller number of independent traits. We test our predictions by comparing empirical f(s) across species of various gene numbers as a surrogate to complexity. This survey reveals, as predicted, that mutations tend to be more deleterious, less variable, and less skewed in higher organisms. However, only limited difference in the shape of f(s) is observed from Escherichia coli to nematodes or fruit flies, a pattern consistent with a model of random phenotypic interactions across many traits. Overall, these results suggest that there may be a cost to phenotypic complexity although much weaker than previously suggested by earlier theoretical works. More generally, the model seems to qualitatively capture and possibly explain the variation of f(s) from lower to higher organisms, which opens a large array of potential applications in evolutionary genetics.

Animals↗
PubMed1998

Treatment of antimony-unresponsive Indian visceral leishmaniasis with ultra-short courses of amphotericin-B-lipid complex.

High cost is the principal drawback of treating visceral leishmaniasis (VL; kala-azar) with any of the new lipid formulations of amphotericin B. The aim of the present study was to see if the costs of treatment with such drugs could be reduced by using ultra-short courses. Amphotericin-B-lipid complex (ABLC) was given to 77 Indian patients with antimony-unresponsive VL, either as a single infusion of 5 mg/kg (Group A) or two infusions, each of 5 mg/kg, given 5 days apart (Group B) or on consecutive days (Group C). Other than the anticipated higher fever and chills, treatment was well-tolerated. On day 19 after first infusion, 72 patients were considered apparent cures: 24 (89%) of the 27 in Group A; all 24 (100%) in Group B; and 24 (92%) of the 26 patients in Group C. Six months after treatment, 19 (70%) of 27 in Group A, 19 (79%) of 24 in Group B, and 21 (81%) of 26 in Group C were healthy, relapse-free and considered definitive cures. These cure rates were not statistically different. All 18 treatment failures (five initial non-responders and 13 relapses) were cured after treatment with a 5-day course of ABLC at a higher dose (10-15 mg/kg.day). In a related analysis of hospital plus drug costs for treating antimony-unresponsive VL, short-course ABLC (1-5 days) was compared with conventional amphotericin B (0.75-1.0 mg/kg on alternate days over 30-34 days). This analysis, which included the cost of re-treatment, identified one short-course ABLC regimen with an overall estimated expense which was only modestly higher than that of amphotericin B. Together, the present results provide further support for the use of ABLC in the management of VL patients who fail antimony therapy.

Adolescent↗
PubMed2000

The multifunctional therapy room of the future: image guidance, interdisciplinarity, integration and impact on patient pathways.

With few exceptions the interventional rooms of the present are either imaging suites or sterile operating rooms. Their users are restricted to either percutaneous procedures or to two-staged image-guided surgery without intra-operative imaging control. Since interventional therapy of the future will be minimally invasive and since minimally invasive therapy is essentially image-guided therapy, a new physical place for these activities has to be devised: the multifunctional therapy room of the future integrates sophisticated imaging and image guidance modalities together with advanced surgical and life-support equipment in a sterile environment [1, 2, 3]. Even given a high degree of integration, this will be a complex and costly piece of medical technology. These two factors--complexity and cost-- require interdisciplinary technological and medical collaboration to bring it into existence, distribute its cost and maximize usage and medical benefit. Yet another dimension of multifunctionality will be introduced and a significant impact on the care of vitally threatened patients will be exerted by using this room not only for elective image-guided therapy but also for emergent one-stop diagnosis and treatment. Motivation, technology, implementation strategies and funding of this image-guided, integrated and interdisciplinary therapy room, as well as a comprehensive approach combining emergency care and elective computer-assisted therapy (CAT), are discussed in this paper.

Critical Pathways↗
PubMedDate not supplied

Line-scanning laser ophthalmoscope.

Scanning laser ophthalmoscopy (SLO) is a powerful imaging tool with specialized applications limited to research and ophthalmology clinics due in part to instrument size, cost, and complexity. Conversely, low-cost retinal imaging devices have limited capabilities in screening, detection, and diagnosis of diseases. To fill the niche between these two, a hand-held, nonmydriatic line-scanning laser ophthalmoscope (LSLO) is designed, constructed, and tested on normal human subjects. The LSLO has only one moving part and uses a novel optical approach to produce wide-field confocal fundus images. Imaging modes include multiwavelength illumination and live stereoscopic imaging with a split aperture. Image processing and display functions are controlled with two stacked prototype compact printed circuit boards. With near shot-noise limited performance, the digital LSLO camera requires low illumination power (<500 microW) at near-infrared wavelengths. The line-scanning principle of operation is examined in comparison to SLO and other imaging modes. The line-scanning approach produces high-contrast confocal images with nearly the same performance as a flying-spot SLO. The LSLO may significantly enhance SLO utility for routine use by ophthalmologists, optometrists, general practitioners, and also emergency medical personnel and technicians in the field for retinal disease detection and other diverse applications.

Computer-Aided Design↗
PubMed1988

Cost-effectiveness in healthcare: complexity of the equation.

Integrating scientific changes, citizens' needs and economic constraints has become a challenge. New types of cost-effective services, technologies and products must be found. Manufacturers, hospital administrators and health professionals must be capable of effectively documenting the benefits, risks and costs of their services to society and the quality of care to patients. Choices must be made to decide upon appropriate actions in allocating and using resources. The concepts of cost-benefit analysis and cost-effectiveness analysis should be understood. Identifying and valuing costs and benefits, measuring effectiveness, and assessing quality of life are complex and difficult issues. They are discussed in reference to Canadian studies on the cost-effectiveness of nutrition support. The need for further research to improve cost-effectiveness of nutrition support is stressed.

Canada↗
PubMed2004

Protein complex prediction via cost-based clustering.

MOTIVATION: Understanding principles of cellular organization and function can be enhanced if we detect known and predict still undiscovered protein complexes within the cell's protein-protein interaction (PPI) network. Such predictions may be used as an inexpensive tool to direct biological experiments. The increasing amount of available PPI data necessitates an accurate and scalable approach to protein complex identification. RESULTS: We have developed the Restricted Neighborhood Search Clustering Algorithm (RNSC) to efficiently partition networks into clusters using a cost function. We applied this cost-based clustering algorithm to PPI networks of Saccharomyces cerevisiae, Drosophila melanogaster and Caenorhabditis elegans to identify and predict protein complexes. We have determined functional and graph-theoretic properties of true protein complexes from the MIPS database. Based on these properties, we defined filters to distinguish between identified network clusters and true protein complexes. CONCLUSIONS: Our application of the cost-based clustering algorithm provides an accurate and scalable method of detecting and predicting protein complexes within a PPI network.

Algorithms↗