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1.
Pacing Clin Electrophysiol ; 40(11): 1206-1212, 2017 Nov.
Article in English | MEDLINE | ID: mdl-28901573

ABSTRACT

INTRODUCTION: Visualization of left atrial (LA) anatomy using image integration modules has been associated with decreased radiation exposure and improved procedural outcome when used for guidance of pulmonary vein isolation (PVI) in atrial fibrillation (AF) ablation. We evaluated the CARTOSEG™ CT Segmentation Module (Biosense Webster, Inc.) that offers a new CT-specific semiautomatic reconstruction of the atrial endocardium. METHODS: The CARTOSEG™ CT Segmentation Module software was assessed prospectively in 80 patients undergoing AF ablation. Using preprocedural contrast-enhanced computed tomography (CE-CT), cardiac chambers, coronary sinus (CS), and esophagus were semiautomatically segmented. Segmentation quality was assessed from 1 (poor) to 4 (excellent). The reconstructed structures were registered with the electroanatomic map (EAM). PVI was performed using the registered 3D images. RESULTS: Semiautomatic reconstruction of the heart chambers was successfully performed in all 80 patients with AF. CE-CT DICOM file import, semiautomatic segmentation of cardiac chambers, esophagus, and CS was performed in 185 ± 105, 18 ± 5, 119 ± 47, and 69 ± 19 seconds, respectively. Average segmentation quality was 3.9 ± 0.2, 3.8 ± 0.3, and 3.8 ± 0.2 for LA, esophagus, and CS, respectively. Registration accuracy between the EAM and CE-CT-derived segmentation was 4.2 ± 0.9 mm. Complications consisted of one perforation (1%) which required pericardiocentesis, one increased pericardial effusion treated conservatively (1%), and one early termination of ablation due to thrombus formation on the ablation sheath without TIA/stroke (1%). All targeted PVs (n  =  309) were successfully isolated. CONCLUSIONS: The novel CT- CARTOSEG™ CT Segmentation Module enables a rapid and reliable semiautomatic 3D reconstruction of cardiac chambers and adjacent anatomy, which facilitates successful and safe PVI.


Subject(s)
Atrial Fibrillation/diagnostic imaging , Atrial Fibrillation/surgery , Catheter Ablation , Pulmonary Veins/surgery , Software Validation , Tomography, X-Ray Computed , Contrast Media , Echocardiography, Transesophageal , Electrophysiologic Techniques, Cardiac , Female , Humans , Male , Middle Aged , Pericardiocentesis , Prospective Studies , Radio Waves , Radiographic Image Interpretation, Computer-Assisted
2.
J Am Coll Radiol ; 13(3): 335-43, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26482814

ABSTRACT

PURPOSE: The objective of this study was to conduct a usability evaluation of mobile apps for supporting education and training in radiologic diagnostic decision-making processes. METHODS: Of 381 mobile apps available at two major stores (Google Play and iTunes), eight iOS apps were selected for laboratory-based usability tests. Six staff radiologists completed eight app-specific task sets, using a think-aloud strategy. The triangular methods approach included quantitative performance measures, System Usability Scale (SUS), and qualitative thematic analysis using heuristic usability principles of usability issues. RESULTS: Overall, radiologists achieved higher than 70% success, with favorable SUS scores, in completing the tasks for seven of the eight apps. However, task success rate and SUS score had a weak relation (r = 0.23), indicating that the perceived usability may not reflect the holistic usability of the app. Task analysis and self-report revealed 108 usability issues, which were condensed to 55 unique issues and categorized by nine usability themes and mapped to ten usability heuristics. Nonintuitive functionality (eg, nonintuitive or misleading labels) was the most frequent theme observed, leading to inefficient navigation. These usability findings were consistent with the 13 improvements the radiologists suggested. CONCLUSIONS: This study demonstrates the feasibility of usability evaluation of radiology mobile apps and suggests potential improvements in the development of radiology mobile apps. This study also suggests that proficiency with mobile devices may not be equivalent to being an expert user, proficient in using the apps.


Subject(s)
Attitude of Health Personnel , Computer-Assisted Instruction/statistics & numerical data , Decision Making , Decision Support Systems, Clinical/statistics & numerical data , Mobile Applications/statistics & numerical data , Radiology/education , Radiology/statistics & numerical data , Software Validation , Utilization Review
3.
Appl Clin Inform ; 5(3): 731-45, 2014.
Article in English | MEDLINE | ID: mdl-25298813

ABSTRACT

BACKGROUND: Federated medical search engines are health information systems that provide a single access point to different types of information. Their efficiency as clinical decision support tools has been demonstrated through numerous evaluations. Despite their rigor, very few of these studies report holistic evaluations of medical search engines and even fewer base their evaluations on existing evaluation frameworks. OBJECTIVES: To evaluate a federated medical search engine, MedSocket, for its potential net benefits in an established clinical setting. METHODS: This study applied the Human, Organization, and Technology (HOT-fit) evaluation framework in order to evaluate MedSocket. The hierarchical structure of the HOT-factors allowed for identification of a combination of efficiency metrics. Human fit was evaluated through user satisfaction and patterns of system use; technology fit was evaluated through the measurements of time-on-task and the accuracy of the found answers; and organization fit was evaluated from the perspective of system fit to the existing organizational structure. RESULTS: Evaluations produced mixed results and suggested several opportunities for system improvement. On average, participants were satisfied with MedSocket searches and confident in the accuracy of retrieved answers. However, MedSocket did not meet participants' expectations in terms of download speed, access to information, and relevance of the search results. These mixed results made it necessary to conclude that in the case of MedSocket, technology fit had a significant influence on the human and organization fit. Hence, improving technological capabilities of the system is critical before its net benefits can become noticeable. CONCLUSIONS: The HOT-fit evaluation framework was instrumental in tailoring the methodology for conducting a comprehensive evaluation of the search engine. Such multidimensional evaluation of the search engine resulted in recommendations for system improvement.


Subject(s)
Attitude to Computers , Consumer Behavior/statistics & numerical data , Data Mining/statistics & numerical data , Health Information Systems/statistics & numerical data , Search Engine/statistics & numerical data , Software , User-Computer Interface , Information Dissemination , Software Validation , United States
4.
Klin Monbl Augenheilkd ; 231(2): 164-9, 2014 Feb.
Article in German | MEDLINE | ID: mdl-23775290

ABSTRACT

PURPOSE: Imaging methods of the optic nerve head appear to have an increasing impact in glaucoma diagnosis. The aim of this study is to evaluate the specifity of the Heidelberg Retina Tomograph (software version 1.7 and 3.0) in subjects with physiological cupping and large optic discs. PATIENTS AND METHODS: 27 eyes of 27 subjects (mean age 41.3 ± 15.8 years) with bilateral physiological cupping and large optic discs (vertical cup-to-disc-ratio > 0.3, optic disc area 2.48 ± 0.45 mm2, max. 3.54 mm2) were included in a clinical study. All subjects had an intraocular pressure < 22 mmHg, physiological cupping by funduscopy and no nerve fibre layer defects (Scanning Laser Ophthalmoscope, Rodenstock, Germany). Standard achromatic perimetry (Humphrey Field Analyzer, Humphrey-Zeiss, 24/2 SITA or full threshold), short-wavelength automated perimetry (Humphrey Field Analyzer, Humphrey-Zeiss), and frequency doubling technology (FDT, Humphrey-Zeiss) revealed no visual field defects. Optic disc imaging was performed in all subjects using the Heidelberg Retina Tomograph II (HRT). Optic disc images were transferred to the software-update of the HRT 3 (Version 3.0, Heidelberg Engineering). Specifity was calculated using the Moorfields regression analysis (MRA, software version 1.7 and 3.0) and the glaucoma probability score (GPS analysis) using all disc sectors and omitting the nasal and 3 nasal sectors. RESULTS: Specifity of the MRA (software version 1.7) was 66.6 % (most specific criteria), and 22.2 % (least specific criteria). Specifity of the MRA (software version 3.0) was 33.3 % (most specific criteria), and 14.8 % (least specific criteria), whereas specifity of the GPS analysis was 37.0 % (most specific criteria), and 11.1 % (least specific criteria). When the nasal sectors were omitted for analysis, specifity increased for the MRA analysis, but not for the GPS analysis. CONCLUSIONS: Specifity of the MRA was unsatisfactory using the software version 1.7 and 3.0 in subjects with large optic discs and physiological cupping when the nasal sectors were included in the analysis. The observer-independent GPS analysis did not improve the results in these subjects.


Subject(s)
Image Interpretation, Computer-Assisted/instrumentation , Image Interpretation, Computer-Assisted/methods , Microscopy, Confocal/instrumentation , Microscopy, Confocal/methods , Ophthalmoscopy/methods , Optic Disk/cytology , Software , Equipment Design , Equipment Failure Analysis , Humans , Organ Size , Reference Values , Reproducibility of Results , Sensitivity and Specificity , Software Validation
5.
BMC Neurosci ; 12: 100, 2011 Oct 11.
Article in English | MEDLINE | ID: mdl-21989414

ABSTRACT

BACKGROUND: To date, some of the most useful and physiologically relevant neuronal cell culture systems, such as high density co-cultures of astrocytes and primary hippocampal neurons, or differentiated stem cell-derived cultures, are characterized by high cell density and partially overlapping cellular structures. Efficient analytical strategies are required to enable rapid, reliable, quantitative analysis of neuronal morphology in these valuable model systems. RESULTS: Here we present the development and validation of a novel bioinformatics pipeline called NeuriteQuant. This tool enables fully automated morphological analysis of large-scale image data from neuronal cultures or brain sections that display a high degree of complexity and overlap of neuronal outgrowths. It also provides an efficient web-based tool to review and evaluate the analysis process. In addition to its built-in functionality, NeuriteQuant can be readily extended based on the rich toolset offered by ImageJ and its associated community of developers. As proof of concept we performed automated screens for modulators of neuronal development in cultures of primary neurons and neuronally differentiated P19 stem cells, which demonstrated specific dose-dependent effects on neuronal morphology. CONCLUSIONS: NeuriteQuant is a freely available open-source tool for the automated analysis and effective review of large-scale high-content screens. It is especially well suited to quantify the effect of experimental manipulations on physiologically relevant neuronal cultures or brain sections that display a high degree of complexity and overlap among neurites or other cellular structures.


Subject(s)
Image Cytometry/methods , Neurites/ultrastructure , Neurogenesis/physiology , Software Validation , Software/standards , Algorithms , Animals , Cell Culture Techniques/methods , Cell Line , Computational Biology/methods , Drug Evaluation, Preclinical/methods , Information Dissemination/methods , Mice , Nerve Growth Factors/physiology , Neurites/physiology
6.
Radiat Prot Dosimetry ; 143(2-4): 135-8, 2011 Feb.
Article in English | MEDLINE | ID: mdl-21183539

ABSTRACT

Monte Carlo track simulation has become an important tool in radiobiology. Monte Carlo transport codes commonly rely on elastic and inelastic electron scattering cross sections determined using theoretical methods supplemented with gas-phase data; experimental condensed phase data are often unavailable or infeasible. The largest uncertainties in the theoretical methods exist for low-energy electrons, which are important for simulating electron track ends. To test the reliability of these codes to deal with low-energy electron transport, yields of low-energy secondary electrons ejected from thin foils have been measured following passage of fast protons. Fast ions, where interaction cross sections are well known, provide the initial spectrum of low-energy electrons that subsequently undergo elastic and inelastic scattering in the material before exiting the foil surface and being detected. These data, measured as a function of the energy and angle of the emerging electrons, can provide tests of the physics of electron transport. Initial measurements from amorphous solid water frozen to a copper substrate indicated substantial disagreement with MC simulation, although questions remained because of target charging. More recent studies, using different freezing techniques, do not exhibit charging, but confirm the disagreement seen earlier between theory and experiment. One now has additional data on the absolute differential electron yields from copper, aluminum and gold, as well as for thin films of frozen hydrocarbons. Representative data are presented.


Subject(s)
Algorithms , Electron Transport , Models, Chemical , Models, Statistical , Monte Carlo Method , Protons , Software , Computer Simulation , Phase Transition , Software Validation
7.
J Bodyw Mov Ther ; 12(2): 133-45, 2008 Apr.
Article in English | MEDLINE | ID: mdl-19083665

ABSTRACT

Knowing one's waist circumference (WC) is a primary step in assessing risk of disease and health disorders. One concern, however, is the accuracy with which WC measurements are taken. This study attempted to determine the effectiveness of a computer-based tutorial (CBT) in teaching previously untrained individuals to properly self-measure WC. Eighty-three subjects used the CBT to learn and perform WC self-measurement. Validity of the subjects' measurements was determined by comparing their measurements to a traditionally trained and experienced tester's. Bland-Altman and Box-Whisker comparisons revealed an average 1.57cm bias in the subjects' WC measurements. Bland-Altman bias plots illustrated agreement between the subjects' and experienced tester's measurements. Pearson correlation (r=0.97) showed no significant (p<0.0001) difference between the two groups. The results of this experiment suggest that the tested CBT is efficacious in teaching WC self-measurement. The tutorial could be used in the areas of health assessment, standardization, biomedical education and research.


Subject(s)
Computer-Assisted Instruction/methods , Computer-Assisted Instruction/standards , Obesity/diagnosis , Waist Circumference , Adolescent , Adult , Computer-Assisted Instruction/instrumentation , Female , Humans , Male , Middle Aged , Reproducibility of Results , Software Validation , Young Adult
8.
Undersea Hyperb Med ; 35(3): 219-25, 2008.
Article in English | MEDLINE | ID: mdl-18619118

ABSTRACT

Hyperbaric oxygen (HBO2) therapy is increasingly used in the treatment of a wide variety of medical conditions. However, for monoplace chambers, there is some uncertainty when sufficiently high oxygen concentrations are attained, because most chambers are not instrumented to measure oxygen. To remedy this, Microsoft Excel-based software, HBO O2 Smart Guide, was developed to simulate the atmosphere ofmonoplace chambers during treatment. Based upon chamber dimensions, patient weight, oxygen purge rates, desired pressurization, and HBO2 time, the program calculates oxygen concentration, consumption and exposure for each treatment. Software testing was conducted using four different chambers instrumented with an oxygen analyzer. Two purge rate profiles were used: constant, and biphasic (a high initial purge rate was changed to a lower plateau rate when pressurization was reached). Comparison of measured and calculated times to reach 95% oxygen concentration within the chambers demonstrated the software was accurate within 1%. The HBO O2 Smart Guide enables optimum purge profiles to be simulated with resultant potential improvements in HBO2 treatment efficacy, calculation of effective oxygen exposures (actual time during prescribed treatment during which patient breathes > or = 95% oxygen) to enable more accurate comparison of treatment profiles and outcomes, and cost savings in oxygen usage. This software will enable clinicians to provide more consistent HBO2 treatments.


Subject(s)
Hyperbaric Oxygenation/methods , Oxygen/analysis , Software Validation , Software , Hyperbaric Oxygenation/instrumentation , Oxygen Consumption
9.
J Neurol Sci ; 264(1-2): 27-33, 2008 Jan 15.
Article in English | MEDLINE | ID: mdl-17764699

ABSTRACT

PURPOSE: The clinical symptoms of Alzheimer's disease (AD) show great diversity depending on the clinical stage. We investigated the correlation of regional cerebral blood flow (rCBF) changes and the clinical severity of AD patients. METHODS: Thirty-nine AD patients and 16 normal subjects participated in this study. AD patients were divided into three subgroups by clinical severity. Quantitative brain perfusion SPECT analyses were performed using a rCBF quantification software, 3DSRT. RESULTS: In mild AD, significant decreases of rCBF were detected in the bilateral parietal, angular gyrus, pericallosal, thalamus, right temporal and left hippocampal regions. Moderate AD patients showed significantly lower blood flow than those with mild AD only to the right hippocampus. Analysis of the severe AD group revealed a nearly diffuse decrease of rCBF throughout the cerebral cortex except for part of the frontal lobe compared with moderate patients. CONCLUSIONS: These results were consistent with previous findings demonstrated by qualitative analysis of CBF. The decreased thalamic blood flow was noteworthy as this finding has rarely been reported. In consideration of the structure and function of the Papez circuit, which connects the medial temporal lobe and thalamus, a remote metabolic effect might be the cause of lower rCBF in the thalamus.


Subject(s)
Alzheimer Disease/diagnostic imaging , Brain/diagnostic imaging , Cerebral Arteries/diagnostic imaging , Cerebrovascular Circulation/physiology , Software/trends , Tomography, Emission-Computed, Single-Photon/methods , Aged , Aged, 80 and over , Algorithms , Alzheimer Disease/metabolism , Alzheimer Disease/physiopathology , Blood Flow Velocity/physiology , Brain/blood supply , Brain/physiopathology , Brain Mapping/methods , Cerebral Arteries/metabolism , Cerebral Arteries/physiopathology , Cerebral Cortex/blood supply , Cerebral Cortex/diagnostic imaging , Cerebral Cortex/physiopathology , Disease Progression , Female , Functional Laterality/physiology , Humans , Image Processing, Computer-Assisted/methods , Image Processing, Computer-Assisted/trends , Imaging, Three-Dimensional/methods , Imaging, Three-Dimensional/trends , Male , Neural Pathways/blood supply , Neural Pathways/diagnostic imaging , Neural Pathways/physiopathology , Predictive Value of Tests , Prognosis , Reproducibility of Results , Software Validation , Thalamus/blood supply , Thalamus/diagnostic imaging , Thalamus/physiopathology
10.
J Digit Imaging ; 20 Suppl 1: 101-18, 2007 Nov.
Article in English | MEDLINE | ID: mdl-17786517

ABSTRACT

The Medical Image Processing Group at the University of Pennsylvania has been developing (and distributing with source code) medical image analysis and visualization software systems for a long period of time. Our most recent system, 3DVIEWNIX, was first released in 1993. Since that time, a number of significant advancements have taken place with regard to computer platforms and operating systems, networking capability, the rise of parallel processing standards, and the development of open-source toolkits. The development of CAVASS by our group is the next generation of 3DVIEWNIX. CAVASS will be freely available and open source, and it is integrated with toolkits such as Insight Toolkit and Visualization Toolkit. CAVASS runs on Windows, Unix, Linux, and Mac but shares a single code base. Rather than requiring expensive multiprocessor systems, it seamlessly provides for parallel processing via inexpensive clusters of work stations for more time-consuming algorithms. Most importantly, CAVASS is directed at the visualization, processing, and analysis of 3-dimensional and higher-dimensional medical imagery, so support for digital imaging and communication in medicine data and the efficient implementation of algorithms is given paramount importance.


Subject(s)
Diagnostic Imaging , Image Processing, Computer-Assisted , Radiology Information Systems , Software , Algorithms , Computer Communication Networks , Computer Systems , Database Management Systems , Humans , Imaging, Three-Dimensional , Information Storage and Retrieval , Software Design , Software Validation , Systems Integration , User-Computer Interface
11.
Health Serv Res ; 42(2): 908-27, 2007 Apr.
Article in English | MEDLINE | ID: mdl-17362224

ABSTRACT

OBJECTIVE: To develop and validate a software algorithm to detect pregnancy episodes and maternal morbidities using automated data. DATA SOURCES/STUDY SETTING: Automated records from a large integrated health care delivery system (IHDS), 1998-2001. STUDY DESIGN: Through complex linkages of multiple automated information sources, the algorithm estimated pregnancy histories. We evaluated the algorithm's accuracy by comparing selected elements of the pregnancy history obtained by the algorithm with the same elements manually abstracted from medical records by trained research staff. DATA COLLECTION/EXTRACTION METHODS: The algorithm searched for potential pregnancy indicators within diagnosis and procedure codes, as well as laboratory tests, pharmacy dispensings, and imaging procedures associated with pregnancy. PRINCIPAL FINDINGS: Among 32,847 women with potential pregnancy indicators, we identified 24,680 pregnancies occuring to 21,001 women. Percent agreement between the algorithm and medical records review on pregnancy outcome, gestational age, and pregnancy outcome date ranged from 91 percent to 98 percent. The validation results were used to refine the algorithm. CONCLUSIONS: This pregnancy episode grouper algorithm takes advantage of databases readily available in IHDS, and has important applications for health system management and clinical care. It can be used in other settings for ongoing surveillance and research on pregnancy outcomes, pregnancy-related morbidities, costs, and care patterns.


Subject(s)
Algorithms , Delivery of Health Care, Integrated/organization & administration , Medical Records Systems, Computerized/organization & administration , Pregnancy , Software Design , Adolescent , Adult , Female , Gestational Age , Humans , Middle Aged , Pregnancy Outcome , Software Validation
12.
Assay Drug Dev Technol ; 3(5): 483-99, 2005 Oct.
Article in English | MEDLINE | ID: mdl-16305306

ABSTRACT

This report describes statistical validation methods implemented on assay data for inhibition of subcellular redistribution of nuclear factor kappaB (NF kappaB) in HeLa cells. We quantified cellular inhibition of cytoplasmic-nuclear translocation of NF kappaB in response to a range of concentrations of interleukin-1 (IL-1) receptor antagonist in the presence of IL-1alpha using eight replicate rows in each four 96-well plates scanned five times on each of 2 days. Translocation was measured as the fractional localized intensity of the nucleus (FLIN), an implementation of our more general fractional localized intensity of the compartments (FLIC), which analyzes whole compartments in the context of the entire cell. The NF kappaB antagonist assay (inhibition of IL-1- induced NF kappaB translocation) data were collected on a Q3DM (San Diego, CA) EIDAQtrade mark 100 high throughput microscopy system. [In 2003, Q3DM was purchased by Beckman Coulter Inc. (Fullerton, CA), which released the IC 100 successor to the EIDAQ 100.] The generalized FLIC method is described along with two-point (minimum-maximum) and multiple point titration statistical methods. As a ratio of compartment intensities that tend to change proportionally, FLIN was resistant to photobleaching errors. Two-point minimum-maximum statistical analyses yielded the following: a Z' of 0.174 with the data as n = 320 independent well samples; Z' by row data in a range of 0.393-0.933, with a mean of 0.766; by-plate Z' data of 0.310, 0.443, 0.545, and 0.794; and by-plate means of columns Z' data of 0.879, 0.927, 0.945, and 0.963. The mean 50% inhibitory concentration (IC50) for IL-1 receptor antagonist over all experiments was 213 ng/ml. The combined IC50 coefficients of variation (CVs) were 0.74%, 0.85%, 2.09%, and 2.52% for the four plates. Repeatability IC50 CVs were as follows: day to day 3.0%, row to row 8.0%, plate to plate 2.8%, and day to day 0.6%. The number of cells required for statistically resolvable differences in dose concentrations, plotted in a family of FLIN sigma/deltamicro (SD/range) curves and tabulated, demonstrated cell-by-cell assay precision with our combined sigma/deltamicro = 0.32 that required approximately 10-fold fewer cells than in a previously reported NF kappaB assay with sigma/deltamicro = 1.52. To better understand the relationship between cell-by-cell measurements and IC50 precision, 500 Monte Carlo simulations with varying cell-measurement SDs were used to explore three-, five-, seven-, and 11-point model titrations. The reductions in deltaIC50 90% confidence intervals from 11- to three-point titrations were 10-fold with the previously reported sigma/deltamicro = 1.52 and twofold with our sigma/deltamicro = 0.32. With these normalized parameters, this report provides a common statistical foundation, independent of the assay details, for evaluating the performance of imaging data on any instrument.


Subject(s)
Active Transport, Cell Nucleus/physiology , Biological Assay/methods , Cell Nucleus/metabolism , Image Interpretation, Computer-Assisted/methods , Microscopy, Fluorescence/methods , NF-kappa B/metabolism , Receptors, Interleukin-1/antagonists & inhibitors , Sialoglycoproteins/administration & dosage , Active Transport, Cell Nucleus/drug effects , Algorithms , Cell Count/methods , Cell Nucleus/ultrastructure , Data Interpretation, Statistical , Dose-Response Relationship, Drug , Drug Evaluation, Preclinical/methods , HeLa Cells , Humans , Interleukin 1 Receptor Antagonist Protein , Protein Transport/drug effects , Protein Transport/physiology , Reproducibility of Results , Sensitivity and Specificity , Software , Software Validation
13.
J Urol ; 172(5 Pt 1): 1953-7, 2004 Nov.
Article in English | MEDLINE | ID: mdl-15540764

ABSTRACT

PURPOSE: We examined the face, content and construct validity of version 1.0 of the University of Washington transurethral prostate resection (TURP) trainer. MATERIALS AND METHODS: Version 1.0 of a virtual reality based simulator for transurethral skills was developed at our laboratory by integrating TURP hardware with our virtual 3-dimensional anatomy, irrigation control, cutting, bleeding and haptics force feedback. A total of 72 board certified urologists and 19 novices completed a pre-task questionnaire, viewed an introductory training video and performed a pre-compiled 5-minute resection task. The simulator logged operative errors, gm resected, blood loss, irrigant volume, foot pedal use and differential time spent with orientation, cutting or coagulation. Trainees and experts evaluated the simulator on a modified likert scale. The 2-tailed Levene t test was used to compare means between experts and novices. RESULTS: Overall version 1.0 content was between slightly and moderately acceptable. Experts spent less time with orientation (p < 0.0001), resected more total tissue (p < 0.0001), had more gm resected per cut (p = 0.002) and less blood loss per gm resected (p = 0.032), used less irrigant per gm resected (p = 0.02) and performed fewer errors (p < 0.0001) than novices. CONCLUSIONS: We established the face, content and construct validity for version 1.0 of the University of Washington TURP trainer to simulate the skills necessary to perform TURP. A predictive validity study showing a translation of skills from the virtual environment to the operating room will complete the validation of this model.


Subject(s)
Computer Simulation , Software Validation , Transurethral Resection of Prostate/education , Adult , Aged , Humans , Middle Aged , User-Computer Interface
14.
J Environ Radioact ; 53(3): 381-98, 2001.
Article in English | MEDLINE | ID: mdl-11379064

ABSTRACT

In this paper, an adaptation of a spectral profile analysis method, currently used in high-resolution spectrometry, to airborne gamma measurements is presented. A new algorithm has been developed for extraction of full absorption peaks by studying the variations in the spectral profile of data recorded with large-volume NaI detectors (16 l) with a short sampling time (2 s). The use of digital filters, taking into consideration the characteristics of the absorption peaks, significantly reduced the counting fluctuations, making detection possible based on study of the first and second derivatives. The absorption peaks are then obtained by modelling, followed by subtraction of the Compton continuum in the detection window. Compared to the conventional stripping ratio method, spectral profile analysis offers similar performance for the natural radioelements. The 137Cs 1SD detection limit is approximately 1200 Bq/m2 in a natural background of 200 Bq/kg 40K, 33 Bq/kg 238U and 33 Bq/kg 232Th. At low energy the very high continuum leads to detection limits similar to those obtained by the windows method, but the results obtained are more reliable. In the presence of peak overlaps, however, analysis of the spectral profile alone is not sufficient to separate the peaks, and further processing is necessary. Within the framework of environmental monitoring studies, spectral profile analysis is of great interest because it does not require any assumptions about the nature of the nuclides. The calculation of the concentrations from the results obtained is simple and reliable, since only the full absorption contributions are taken into consideration. A quantitative estimate of radioactive anomalies can thus be obtained rapidly.


Subject(s)
Air Pollution, Radioactive/analysis , Algorithms , Radiation Monitoring/methods , Signal Processing, Computer-Assisted , Software Validation , Spectrometry, Gamma/methods , Cesium Radioisotopes/analysis , Finland , Humans , Potassium Radioisotopes/analysis , Radiation Monitoring/instrumentation , Radiation Monitoring/standards , Spectrometry, Gamma/instrumentation , Spectrometry, Gamma/standards , Thorium/analysis , Uranium/analysis
15.
Proc AMIA Symp ; : 731-5, 2001.
Article in English | MEDLINE | ID: mdl-11825282

ABSTRACT

Critical parts of the software development life cycle are concerned with eliciting, understanding, and managing requirements. Though the literature on this subject dates back for several decades, practicing effective requirements development remains a current and challenging area. Some projects flourish with a requirements development process (RDP) that is implicit and informal, but this approach may be overly risky, particularly for large projects that involve multiple individuals, groups, and systems over time. At Partners HealthCare System in Boston, Massachusetts, we have applied a more formal approach for requirements development to the Patient Computing Project. The goal of the project is to create web-based software that connects patients electronically with their physician's offices and has the potential to improve care efficiency and quality. It is a large project, with over 500 function points. Like most technological innovation, the successful introduction of this system requires as much attention to understanding the business needs and workflow details as it does to technical design and implementation. This paper describes our RDP approach, and key business requirements discovered through this process. We believe that a formal RDP is essential, and that informatics as a field must include proficiencies in this area.


Subject(s)
Internet , Software Validation , Software/standards , Telemedicine/standards , Boston , Delivery of Health Care, Integrated , Humans , Patients , Physician-Patient Relations
16.
IEEE Trans Rehabil Eng ; 8(3): 305-11, 2000 Sep.
Article in English | MEDLINE | ID: mdl-11001510

ABSTRACT

This paper proposes a fuzzy approach to classify single-site electromyograph (EMG) signals for multifunctional prosthesis control. While the classification problem is the focus of this paper, the ultimate goal is to improve myoelectric system control performance, and classification is an essential step in the control. Time segmented features are fed to a fuzzy system for training and classification. In order to obtain acceptable training speed and realistic fuzzy system structure, these features are clustered without supervision using the Basic Isodata algorithm at the beginning of the training phase, and the clustering results are used in initializing the fuzzy system parameters. Afterwards, fuzzy rules in the system are trained with the back-propagation algorithm. The fuzzy approach was compared with an artificial neural network (ANN) method on four subjects, and very similar classification results were obtained. It is superior to the latter in at least three points: slightly higher recognition rate; insensitivity to overtraining; and consistent outputs demonstrating higher reliability. Some potential advantages of the fuzzy approach over the ANN approach are also discussed.


Subject(s)
Algorithms , Artificial Limbs , Electric Stimulation Therapy , Electromyography/classification , Electromyography/methods , Feedback , Fuzzy Logic , Neural Networks, Computer , Signal Processing, Computer-Assisted , Bias , Cluster Analysis , Electric Stimulation Therapy/methods , Humans , Software Validation , Time Factors
17.
IEEE Trans Rehabil Eng ; 8(3): 312-9, 2000 Sep.
Article in English | MEDLINE | ID: mdl-11001511

ABSTRACT

Rule based detectors were used with a single cluster of accelerometers attached to the shank for the real time detection of the main phases of normal gait during walking. The gait phase detectors were synthesized from two rule induction algorithms, Rough Sets (RS) and Adaptive Logic Networks (ALNs), and compared with to a previously reported stance/swing detector based on a hand crafted, rule based algorithm. Data was sampled at 100 Hz and the detection errors determined at each sample for 50 steps. For three able bodied subjects, the sample by sample accuracy of stance/swing detection ranged within 94-97%, 87-94%, and 87-95% for the RS, ALN, and the handcrafted methods, respectively. A heuristically formulated postdetector filter improved the RS and ALN detectors' accuracy to 98%. RS and ALN also detected five gait phases to an overall accuracy of 82-89% and 86-91%, respectively. The postdetector filter localized the errors to the phase transitions, but did not change the detection accuracy. The average duration of the error at each transition was 40 ms and 23 ms for RS and ALN, respectively. When implemented on a microcontroller, the RS-based detector executed ten times faster and required one tenth of the memory than the ALN-based detector.


Subject(s)
Acceleration , Algorithms , Electric Stimulation Therapy/instrumentation , Electric Stimulation Therapy/methods , Gait/physiology , Neural Networks, Computer , Signal Processing, Computer-Assisted/instrumentation , Software Validation , Walking/physiology , Adult , Bias , Decision Trees , Humans , Minicomputers , Paraplegia/physiopathology , Paraplegia/rehabilitation , Weight-Bearing
18.
Comput Methods Programs Biomed ; 54(1-2): 101-13, 1997 Sep.
Article in English | MEDLINE | ID: mdl-9290925

ABSTRACT

The procurement and implementation of patient administration systems has been done on numerous occasions in the past. The Rotunda project however encompassed major bespoke clinical developments which were going to impact upon large clusters of midwives, and medical staff to a lesser extent. A broad based four level structured methodology was used to implement the project which is significantly ahead of schedule. This methodology together with its strengths and weaknesses is comprehensively discussed. The empowerment of midwives, their roles in systems analysis and design, software testing and organisational re-engineering is described. The importance of undertaking comprehensive computer training is highlighted and a compact 10 h information technology course coupled with ongoing educational and related activities which could be adopted by any organisation is documented. The seven deadly sins of project management are mapped out. An update on benefits realisation is provided. Gender issues are also discussed.


Subject(s)
Computer Systems , Hospital Information Systems , Midwifery , Computer Systems/economics , Computer User Training , Contract Services , Cost-Benefit Analysis , Costs and Cost Analysis , Financial Support , Hospital Administration , Hospital Information Systems/economics , Hospital Information Systems/organization & administration , Hospitals, Maternity , Humans , Information Management , Interpersonal Relations , Medical Records Systems, Computerized , Nursing Staff, Hospital , Ownership , Public Relations , Quality Assurance, Health Care , Software Design , Software Validation , User-Computer Interface
19.
Am J Prev Med ; 4(4): 188-93, 1988.
Article in English | MEDLINE | ID: mdl-3166823

ABSTRACT

The accuracy of historical information derived from self-administered questionnaires must be confirmed. We report the results of studies conducted to assess the reliability and validity of data collected from a comprehensive cancer risk factor questionnaire developed at The University of Texas M.D. Anderson Cancer Center. A comparison of the basic demographic data of a randomly selected sample of 80 respondents and 70 nonrespondents revealed no fundamental ethnic or socioeconomic differences. We verified self-reported past illnesses, surgical procedures, and cancers by reviewing 72 patient charts, using stringent diagnostic criteria for verification. We noted substantial agreement between self-reported and documented illnesses and operations. With the exception of nine patients who misclassified metastatic disease, the verification of primary cancers was excellent. We determined reliability by interviewing 50 of these patients by telephone. Questions with a dichotomous outcome (e.g., smoking status) were reliably answered; however, those requiring quantification (e.g., amount of alcohol consumed) were less accurately reported on interview. While we recognize the limitations of self-administered questionnaires, we believe this program will develop into a comprehensive, standardized, easily accessible patient risk factor data base.


Subject(s)
Database Management Systems/standards , Epidemiologic Methods , Neoplasms/epidemiology , Risk , Software/standards , Cancer Care Facilities , Female , Humans , Male , Sampling Studies , Software Validation , Surveys and Questionnaires , Texas
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