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Computerized tracking of mammography patients: value of a radiology information system integrated with a personal-computer data base.

OBJECTIVE. We investigated the advantages of using a radiology information system as the primary data source for a mammographic patient-tracking system that is based on a personal-computer local-area network and that requires almost no data entry. HARDWARE AND SOFTWARE. Our mammographic data base is maintained on a file server that provides cross-platform access to both Macintosh and IBM-compatible personal computers. Locally developed software automatically transfers mammographic data from our radiology information system to the file server's mammographic data base. The data transferred include patients' demographics (e.g., hospital identification number, address, referring physician) and the complete mammographic report. With the use of specific terminology, the need for follow-up can be automatically gleaned from the mammographic report and coded within the data base. Graphically oriented, commercially available software provides easy access to this information from any personal computer on our department's network. The software provides considerable flexibility for searching and manipulating the data without the need for customized data-base programming. Redundant data entry and associated errors are drastically reduced, as are personnel requirements for maintaining the system. Relative to most commercial radiology information systems, a personal computer facilitates the steps involved in tracking patients and obtaining highly customized analyses of the mammographic data base. The data in the mammographic data base exactly match those in the hospital's registration data and are easily transferred to other personal-computer programs for ancillary processing. CONCLUSION. This technique is ideal for departments that use a general-purpose radiology information system for mammographic reporting, yet need a more powerful but user-friendly and low-cost method for tracking their mammography patients.

Female↗

Noninvasive verification of nasogastric tube placement using a magnet-tracking system: a pilot study in healthy subjects.

BACKGROUND: Fluoroscopic verification of nasogastric (NG) feeding tube placement is inconvenient and involves radiation exposure. We tested whether the position of an NG tube can be assessed reliably by a recently introduced magnet-tracking system. METHODS: A small permanent magnet was attached at the end of an NG tube and its position was monitored using an external sensor array connected to a computer. NG tube trajectory, spontaneous movements of the magnet, and its position relative to the lower esophageal sphincter (LES) and xiphisternum were assessed in 22 healthy subjects and compared with esophageal manometry. In 12 subjects, localization of the magnet was also compared with fluoroscopy. RESULTS: Magnet-tracking displayed NG tube tip movement reproducibly as it moved vertically in the esophagus and then laterally into the stomach. Compared with manometry, the accuracy and sensitivity of magnet tracking for localization of the NG tube tip, above or below the diaphragm, were 100%. Compared with fluoroscopy, the accuracy of NG tube localization by magnet tracking was 100%. With the magnet in the stomach, but not in the esophagus or LES, low amplitude displacements at a frequency of 3 per minute, consistent with gastric slow wave activity, were observed. CONCLUSIONS: Magnet tracking allows accurate, real-time, 3-dimensional localization of an NG tube with respect to anatomic landmarks. Recorded motor patterns are indicative of the position of the NG tube. Magnet tracking may be a useful tool for bedside placement of nasogastric and enteral feeding tubes.

Adult↗

Dual chamber cardiac pacing in children: Single chamber pacing dual chamber sensing cardiac pacemaker or dual chamber pacing and sensing cardiac pacemaker?

BACKGROUND: Dual chamber pacemakers (single chamber pacing dual chamber sensing cardiac pacemaker (VDD) and dual chamber pacing and sensing cardiac pacemaker (DDD)) are being used frequently in children and adolescents. The aim of this study was to verify the safety and performance of the VDD and DDD pacing systems, and to evaluate the differences between two pacing modes with regard to atrial sensing and tracking functions. METHODS: In this study, we evaluated 14 patients with VDD pacing and 15 patients with DDD pacing between 1994 and 2000. In the patient group with VDD pacing, all had congenital or acquired atrioventricular (AV) block. In the patient group with DDD pacing, 11 had congenital or acquired AV block, three had sinus node dysfunction with AV conduction disturbance and one had idiopathic hypertrophic subaortic stenosis. Twenty-eight devices were implanted in the subpectoral area using the transvenous route. After implantation the atrial tracking capabilities of the pacing systems were analyzed by telemetry, Holter monitoring, and treadmill exercise testing. RESULTS: The mean age of patients in the VDD pacing group was younger. The percentage of congenital heart disease was higher in the DDD pacing group. There was no significant difference regarding fluoroscopy time during implantation and follow-up time between the two groups. During implantation, in the VDD pacing group the mean sensed atrial signal was 3.1 +/- 1.3 mV and this decreased to 1.37 +/- 0.68 mV (P < 0.05) during follow-up. This pattern was also observed in DDD group (3 +/- 2 mV vs 1.9 +/- 1.5 mV, P < 0.05). Although the P wave measurement at implantation did not differ between the two groups, it was significantly higher in the DDD pacing group at the last control. Three patients with VDD pacing were reprogrammed to VVI or single chamber pacing and sensing, rate adaptive cardiac pacemaker because of complete loss of AV synchrony. There was no atrial sensing problem in the DDD pacing group. During the follow-up, one patient with VDD pacing developed diaphragmatic stimulation and required lead revision. In one patient with DDD pacing, venous thrombosis occurred in the right subclavian vein and was treated with thrombolytic therapy. During treadmill exercise testing, in one patient with VDD and one patient with DDD pacing temporary failure of atrial sensing occurred. At 24 h Holter monitoring, intermittent loss of atrial sensing was documented in two patients with VDD pacing. CONCLUSIONS: Dual chamber pacing in children with DDD or VDD pacemakers is a suitable method for bradycardia treatment. Atrial sensing problems may occur in VDD pacemakers. Therefore, DDD pacing mode should be preferred whenever suitable for the patient to maintain the AV synchrony.

Adolescent↗

A level set method for determining critical curvatures for drainage and imbibition.

An accurate description of the mechanics of pore level displacement of immiscible fluids could significantly improve the predictions from pore network models of capillary pressure-saturation curves, interfacial areas and relative permeability in real porous media. If we assume quasi-static displacement, at constant pressure and surface tension, pore scale interfaces are modeled as constant mean curvature surfaces, which are not easy to calculate. Moreover, the extremely irregular geometry of natural porous media makes it difficult to evaluate surface curvature values and corresponding geometric configurations of two fluids. Finally, accounting for the topological changes of the interface, such as splitting or merging, is nontrivial. We apply the level set method for tracking and propagating interfaces in order to robustly handle topological changes and to obtain geometrically correct interfaces. We describe a simple but robust model for determining critical curvatures for throat drainage and pore imbibition. The model is set up for quasi-static displacements but it nevertheless captures both reversible and irreversible behavior (Haines jump, pore body imbibition). The pore scale grain boundary conditions are extracted from model porous media and from imaged geometries in real rocks. The method gives quantitative agreement with measurements and with other theories and computational approaches.

Journal Article↗

Variability of myocardial perfusion defects assessed by thallium-201 scintigraphy in patients with coronary artery disease not amenable to angioplasty or bypass surgery.

OBJECTIVES: We sought to assess the variability of results obtained with thallium scintigraphy as a method for tracking the extent of myocardial ischemia in medically refractory patients with angina who are not suitable for coronary artery bypass graft surgery or percutaneous transluminal coronary angioplasty. BACKGROUND: New therapies are being evaluated for patients with "no option" angina in whom medical therapy has failed. Nuclear techniques, like thallium scintigraphy, are used in multicenter trials to evaluate whether such therapies improve myocardial perfusion. However, the variability of test results is unknown in this patient group in a multicenter study. METHODS: The Angina Treatments: Lasers And Normal Therapies In Comparison (ATLANTIC) study was a randomized trial of transmyocardial laser revascularization (n = 182). Patients underwent dipyridamole thallium stress tests at baseline and 3, 6 and 12 months after enrollment. The control group (n = 90) was treated with constant medical therapy during the study and is a relevant group to investigate test variability. Test variability over time was quantified by the mean absolute change in the percentage of reversible perfusion defects between baseline and follow-up. RESULTS: Baseline percent myocardium with ischemia averaged 17.0 +/- 13.7% and did not change during follow-up. However, variations in the percent myocardium with reversible perfusion defects over time amounted to an average of 6 to 8 percentage points, or 43% to 55% of the baseline value. Only approximately 13% of this variability was attributable to variability in image reconstruction and analysis. CONCLUSIONS: As demonstrated in the ATLANTIC study, percent myocardial ischemia in control subjects receiving constant medical therapy varied in individual patients by an average of approximately 50%. This may limit the utility of thallium scintigraphy to detect improved myocardial perfusion over time in response to therapy.

Coronary Disease↗

Phagocytosis of a fluorescently labeled perflubron emulsion by a human monocyte cell line.

We hypothesized that fluorocarbon-based lipid emulsions are phagocytosed by monocytes and that many of the in vivo side effects related to the infusion of these particulate emulsions are due to release of cytokines by these monocytes. To clarify whether these emulsions are actually phagocytosed we attempted to measure by flow cytometry the apparent uptake of a fluorescently labeled high-concentration (90%, w/v) perflubron (perfluorooctyl bromide [PFOB]) emulsion by a differentiated human monocyte cell line. A fluorescent chromophore (Zynaxis Cell Science) was used to label the egg yolk phospholipid in a perflubron emulsion. This phospholipid label was used to track the perflubron emulsion during overnight incubation with the human monocyte (THP-1) cell line which had been differentiated, by exposure to PMA, into macrophage-like cells. Our results indicate that after 24 hours of incubation with the labeled perflubron emulsion, 64.9% (+/- 11.0) of differentiated THP-1 cells had cell-associated emulsion (ingested and/or membrane bound) whereas 24.4 (+/- 6.8%) of the control cells had cell-associated emulsion. We speculate that this technique may be a useful method to track the intravascular persistence and extravascular distribution of such emulsions, and that the degree of uptake of the emulsion by macrophages in this assay may correlate with its in vivo half life.

Cell Line↗

A comparison of DNA profiling techniques for monitoring nutrient impact on microbial community composition during bioremediation of petroleum-contaminated soils.

Amplicon length heterogeneity PCR (LH-PCR) and terminal restriction fragment length polymorphisms (TRFLP) were used to monitor the impact that nutrient amendments had on microbial community dynamics and structural diversity during bioremediation of petroleum-contaminated soils. Slurried soils contaminated with petroleum hydrocarbons were treated in airlift bench-scale bioreactors and were either amended with optimal inorganic nutrients or left unamended. Direct DNA extraction and PCR amplification of whole eubacterial community DNA were performed with universal primers that bracketed the first two or three hypervariable regions of the 16S rDNA gene sequences. The LH-PCR method profiled a more diverse microbial community than did the TRFLP method. The LH-PCR method also tracked differences between the communities due to nutrient amendments. An in silico database search for bacterial genera with amplicon lengths represented in the community fingerprints was performed. It was possible to qualitatively identify different groups in the microbial community based on the amplicon length variations. A similar "virtual" search was performed for the TRFLP fragments using the web-based TAP-TRFLP program. Cloning and sequencing of the PCR products confirmed the in silico database matches. The application of the LH-PCR method as a monitoring tool for bioremediation could greatly enhance and extend the current understanding of the microbial community dynamics during the biodegradation of environmental contaminants.

Bacteria↗

Prediction for human motion tracking failures.

We propose a new and effective method of predicting tracking failures and apply it to the robust analysis of gait and human motion. We define a tracking failure as an event and describe its temporal characteristics using a hidden Markov model (HMM). We represent the human body using a three-dimensional, multicomponent structural model, where each component is designed to independently allow the extraction of certain gait variables. To enable a fault-tolerant tracking and feature extraction system, we introduce a single HMM for each element of the structural model, trained on previous examples of tracking failures. The algorithm derives vector observations for each Markov model using the time-varying noise covariance matrices of the structural model parameters. When transformed with a logarithmic function, the conditional output probability of each HMM is shown to have a causal relationship with imminent tracking failures. We demonstrate the effectiveness of the proposed approach on a variety of multiview video sequences of complex human motion.

Algorithms↗

Polarized light photography and videomicroscopy greatly enhance the capability of estimating the therapeuic response to a topical retinoid (adapalene) in acne vulgaris.

Assessment of improvement in acne lesions following treatment is often based on clinical evaluation and photographs. However, limitations are associated with this sublective evaluation, making it difficult to accurately review individual acne lesions and to observe early response to therapy. Conventional photographs do not allow us to visualize small lesions, and it can be difficult to differentiate inflammatory lesions as papules or small nodules. Our objective was to evaluate a new standardized method for tracking individual acne lesions based on photographs. The effect of adapalene gel 0.1% on both inflammatory and noninflammatory acne lesions was evaluated using this technique. Polarized light photography and videomicroscopy were used to record the evolution of acne lesions over a 16-week period in 5 volunteers with moderate acne vulgaris. During the first 4 weeks before treatment, acne lesions were evaluated on a 3-times weekly basis to establish a pattern of progression and determine the length of time to resolution. Sebum secretion rates were monitored using Sebutape adhesive patches applied to the forehead and both cheeks for 1 hour. After 4 weeks, adapalene gel 0.1% was used once daily at bedtime for 8 weeks; polarized light photography, videomicroscopy, and assessment of sebum production followed treatment response. This treatment period was followed by a further 4-week phase, after which acne lesions and sebum secretion rates were evaluated. Our results showed that the new methodology was appropriate to track acne lesions and allowed an accurate and more oblective evaluation of individual lesions. Using this methodology demonstrated that adapalene gel 0.1% causes rapid resolution of inflammatory and noninflammatory lesions. The probability of clearing inflammatory and noninflamma tory lesions during the treatment period increased, and the probability of new lesions appearing decreased. Sebum secretion rates declined in patients while on study drug, returning to near pretreatment levels following therapy cessation. Using sophisticated photography and videomicroscopy every other day proved to be a valuable, noninvasive, and reliable method of following response to adapalene treatment in patients with moderate acne vulgaris.

Acne Vulgaris↗

Participant-centered adaptations in caregiver trials: strategies for managing confounds.

BACKGROUND: Randomized trials have been criticized for being more protocol than participant-centered, with concerns raised about higher subject attrition and limited generalizability under controlled conditions. Informal caregivers are similar to other participants in community-based trials: many are unlikely to remain in a trial without procedural adaptations to meet some of their needs. PURPOSE: This article discusses design and statistical strategies for tracking potential confounds associated with 3 participant-centered adaptations that may be made in community-based caregiver trials: tailoring multi-component interventions, using interpersonal contacts for participant maintenance, and non-blinding of trial participants. The intent of the article is to initiate dialogue on the seldom-discussed issue of participant-centered adaptations in community-based trials. CONCLUSIONS: Participant-centered adaptations may reduce subject attrition and enhance generalizability, but protocol adaptation can compromise trial integrity. The challenge for investigators is to develop scientifically sound methods for tracking / controlling potential confounds associated with each adaptation.

Adaptation, Psychological↗

Fractal analysis of capacitating human spermatozoa.

While head centroid-derived kinematic values have been determined for the trajectories of hyperactivated human spermatozoa, the definitions are not robust with respect to image sampling frequency and track analysis methods. The determination of the fractal dimension of a trajectory has been suggested as an alternative descriptive parameter for hyperactivated motility. Here, we have investigated two methods for the determination of the fractal dimension of a trajectory. A simple but useful equation was found to be: D = log(n)/[log (n + log (d/L)], where the n is the number of intervals in the trajectory, d is the planar extent of the curve and L is the length of the trajectory. This equation was not influenced by scaling of the trajectory. A fractal dimension (D) >=1.30 was found to define hyperactivated trajectories, and D <= 1.20 defined non-hyperactivated trajetories, reconstructed at both 30 and 60 Hz. However, when circling tracks were studied, all had D > 1.30, even though they were classified as non-hyperactivated by curvilinear velocity and/or amplitude of lateral head displacement values. An analysis of a series of non-ideal track segments suggested a relationship between a track's linearity and its fractal dimension. It was determined by a linear regression analysis that the fractal dimension of a trajectory was inversely proportional to its linearity (r = -0.77, P < 0.001). Although the fractal dimension of a trajectory is a good indicator of its regularity (describing its space-filling properties), it should not be used as the sole criterion for the classification of a trajectory as hyperactivated.

Fractals↗

Tracking disease genes by reverse genetics.

Increasingly, human genes are being identified by the "reverse genetics", or "positional cloning" approach. This molecular genetic strategy is particularly useful in mental illness, for which no readily detectable functional alterations are present to indicate candidate genes. The positional cloning procedure is briefly described. Significant examples of successful positional cloning are presented, including the fragile-X mental retardation syndrome gene. The study of gene expression may be complicated by genetic and non-genetic variability. Genomic imprinting may play a role in several mental illnesses, and may provide an explanation for the unusual inheritance pattern in fragile-X syndrome, for the phenotypic differences observed between Angelman and Prader-Willi syndromes, and for the juvenile onset form of Huntington disease. DNA instability may explain disease anticipation in fragile-X syndrome and myotonic dystrophy. Finally, the prospects of improvements in positional cloning methods for tracking genes responsible for mental illness are briefly discussed.

Chromosome Mapping↗

A quantitative in vitro fluorescence imaging method for phospholipid loss from respirable mineral particles.

Respirable quartz and kaolin particles were treated with fluorescent-labeled phospholipids to model contact of fibrogenic and nonfibrogenic particles with pulmonary surfactant in the alveolar regions of the lung. Particles were used to challenge rat pulmonary macrophages in vitro at times from 1 d to 10 d. The objective was to develop a quantitative method to track surfactant components that adsorb to respirable particles in the lung or inside cells. Confocal laser scanning microscopy was used to image and quantify surfactant remaining on particles internalized by cells. Results indicate that the fluorescent label is removed from quartz particles quickly, with the fluorescence intensity less than 15% of initial value at 3 d, and about 5% at 10 d. In contrast, the kaolin particle-associated fluorescence was still approximately 39% of initial intensity at 3 d, and 10-15% at 10 d. Unchallenged cells showed a background of approximately 5%, and noninternalized particles did not exhibit any loss of fluorescence over the 10-d exposure. The results indicate the method may be useful in label-removal rate studies of respirable particles in vitro, with some cautions and limitations. Results are discussed and compared with similar studies using nonimaging techniques.

Air Pollutants, Occupational↗

Tracking of single fluorescent particles in three dimensions: use of cylindrical optics to encode particle position.

We present a novel optical technique for three-dimensional tracking of single fluorescent particles using a modified epifluorescence microscope containing a weak cylindrical lens in the detection optics and a microstepper-controlled fine focus. Images of small, fluorescent particles were circular in focus but ellipsoidal above and below focus; the major axis of the ellipsoid shifted by 90 degrees in going through focus. Particle z position was determined from the image shape and orientation by applying a peak detection algorithm to image projections along the x and y axes; x, y position was determined from the centroid of the particle image. Typical spatial resolution was 12 nm along the optical axis and 5 nm in the image plane with a maximum sampling rate of 3-4 Hz. The method was applied to track fluorescent particles in artificial solutions and living cells. In a solution of viscosity 30 cP, the mean squared distance (MSD) traveled by a 264 nm diameter rhodamine-labeled bead was linear with time to 20 s. The measured diffusion coefficient, 0.0558 +/- 0.001 micron2/s (SE, n = 4), agreed with the theoretical value of 0.0556 micron2/s. Statistical variability of MSD curves for a freely diffusing bead was in quantitative agreement with Monte Carlo simulations of three-dimensional random walks. In a porous glass matrix, the MSD data was curvilinear and showed reduced bead diffusion. In cytoplasm of Swiss 3T3 fibroblasts, bead diffusion was restricted. The water permeability in individual Chinese Hamster Ovary cells was measured from the z movement of a fluorescent bead fixed at the cell surface in response osmotic gradients; water permeability was increased by > threefold in cells expressing CHIP28 water channels. The simplicity and precision of this tracking method may be useful to quantify the complex trajectories of fluorescent particles in living cells.

3T3 Cells↗

IAEA/EPA international climatic test program for integrating radon detectors. International Atomic Energy Agency/Environmental Protection Agency.

As an element of the joint IAEA-EPA International Radon Metrology Evaluation Program, a climatic test of long-term integrating radon detectors was conducted at the U.S. EPA Radiation and Indoor Environments National Laboratory. The objective of this study was to test the performance of commonly used commercially available long-term 222Rn detector systems under extreme climatological conditions using filtered polycarbonate CR-39 plastic analyzed by the manufacturer using the track-etch method, unfiltered LR-115 film analyzed by the manufacturer, and Teflon based electrets analyzed in the field by EPA using the manufacturer's equipment. The EPA environmental radon chambers were used to expose detectors to extreme cold and dry (less than 4.0 degrees C air temperature and 25% relative humidity) and hot and humid (greater than 35 degrees C air temperature and 85% relative humidity) climatic conditions. During phase I detectors were exposed to low temperatures and low humidities, and during phase II detectors were exposed to high temperatures and high humidities. Typical indoor equilibrium fractions (near 50%) and radon concentrations of about 150 Bq m(-3) were maintained for each phase, which lasted 90 d. The results indicated that the optimal detector for extreme climatic conditions is dependent on the relative importance of bias and precision. Overall, however, the filtered track-etch type detector produced the most reliable results under the extreme conditions.

Air Microbiology↗

Tracking pediatric asthma: the Massachusetts experience using school health records.

The Massachusetts Department of Public Health, in collaboration with the U.S. Centers for Disease Control and Prevention Environmental Public Health Tracking Program, initiated a 3-year statewide project for the routine surveillance of asthma in children using school health records as the primary data source. School district nurse leaders received electronic data reporting forms requesting the number of children with asthma by grade and gender for schools serving grades kindergarten (K) through 8. Verification efforts from an earlier community-level study comparing a select number of school health records with primary care provider records demonstrated a high level of agreement (i.e., > 95%). First-year surveillance targeted approximately one-half (n = 958 schools) of all Massachusetts's K-8 schools. About 78% of targeted school districts participated, and 70% of the targeted schools submitted complete asthma data. School nurse-reported asthma prevalence was as high as 30.8% for schools, with a mean of 9.2%. School-based asthma surveillance has been demonstrated to be a reliable and cost-effective method of tracking disease through use of an existing and enhanced reporting structure.

Adolescent↗

Research papers submitted to Australian Family Physician - types and timelines.

BACKGROUND: Articles published in the research section of Australian Family Physician (AFP) are subject to an editorial process comprising several stages. METHOD: Timelines tracking the movement of each research manuscript submitted to AFP from 2002-2004 through all stages of the editorial process were constructed. Of 179 papers, 130 had sufficiently progressed to be included in this study. Manuscripts were grouped by subject matter into eight categories. RESULTS: Waiting for authors' responses to editorial feedback (with reviewers' reports) was the greatest cause of delay to AFP editorial processes. Peer reviewers took 43 (SD: 102) days to return their report. Authors took 67 (SD: 76) days to resubmit their paper following initial feedback, and a further 48 (SD: 79) days after it had been edited. Mean accumulated time between receipt of a manuscript by AFP and sending it to peer review was 15 days. Once the editorial process was completed, articles were usually published within 3 months. Most research (64%) was on the topic of health services research rather than clinical research (36%). The most common research method was observational (78%) rather than experimental (22%). DISCUSSION: There is less clinical research submitted to AFP than expected for a clinical discipline. Authors and reviewers cause the most delay in manuscripts' passage through the editorial process.

Australia↗

Readmissions for venous thromboembolism: expanding the definition of patient safety indicators.

BACKGROUND: The Agency for Healthcare Research and Quality (AHRQ) defines its venous thromboembolism (VTE) patient safety indicator (PSI) as surgical cases with a secondary diagnosis of pulmonary embolism or deep vein thrombosis. Short-term readmissions for VTE are excluded because most state administrative databases are unable to track readmissions. METHODS: Patients meeting the AHRQ VTE PSI definition and those readmitted with a VTE principal diagnosis within 30 days of a prior surgical hospitalization were identified on the basis of inpatient discharge data. RESULTS: A total of 4,906 surgical discharges in New York met the AHRQ VTE PSI definition in 2001. An additional 1,059 cases of VTE were found when surgical patients with a short-term readmission for VTE were identified. Patients readmitted with VTE were less likely to die but were more likely to have a pulmonary embolism and were more likely to be white and non-Hispanic compared to those who met the AHRQ VTE PSI definition. DISCUSSION: Short-term readmissions for VTE represent potentially important cases to capture when monitoring adverse events. Prophylaxis, monitoring, and patient education may be required after hospital discharge to prevent or treat VTE as early as possible. Data systems that can track patients across multiple admissions to identify complications resulting in short-term readmissions are needed.

Adult↗