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PubMedDate not supplied

Improving educational computer exhibits at radiologic meetings by modifying computer environment: results of an observational study.

An observational study of educational computer exhibits (ECEs) at the 86th Scientific Assembly and Annual Meeting of the Radiological Society of North America in 2000 was performed to determine the frequency with which the ECEs were in working order. At any given time, an average of 10% of the 71 exhibits were found to be inoperable, and, although some exhibits were functioning 100% of the time, others were not functioning up to 55% of the time. These observations underscore the importance of careful design when creating a computer-based exhibit for a meeting. Downtime of ECEs at meetings is the result of both intentional and unintentional user actions. Given that traditional poster presentations are "working" 100% of the time, modifications made to the environment of an exhibit computer to reduce downtime would be beneficial. Several relatively easy computer configuration steps can be taken that will likely improve the amount of time that an exhibit is functional. Electronic exhibits allow a more interactive experience for users and, with some assistance, will continue to be an effective educational tool.

Audiovisual Aids↗
PubMed2006

Airway dimensions measured from micro-computed tomography and high-resolution computed tomography.

Volume averaging results in both over- and underestimation of airway dimensions when they are measured by high-resolution computed tomography (HRCT). The current authors calibrated computerised measurements of airway dimensions from HRCT against a novel three-dimensional micro-computed tomography (CT) standard, which has a 50-fold greater resolution, as well as against traditional morphometry. Inflation-fixed porcine lung cubes were scanned by HRCT and micro-CT. A total of 59 lumen area (Ai), 30 wall area (A(aw)) and 11 lumen volume (Vi) measurements were made. Ai was measured from the cut surface of 11 airways by morphometry. Airways in scanned images were matched using branching points. After calibration, the errors of Ai, A(aw) and Vi HRCT measurements were determined. The current authors found a systematic, size-dependent underestimation of Ai and overestimation of A(aw) from HRCT measurements. This was used to calibrate an HRCT measurement algorithm. The 95% limits of agreement of subsequent measurements were +/-3.2 mm2 for Ai, +/-4.3 mm2 for A(aw), and +/-11.2 mm3 for Vi with no systematic error. Morphometric measurements agreed with micro-CT (+/-2.5 mm2) without systematic error. In conclusion, micro-computed tomography image data from inflation-fixed airways can be used as calibration standards for three-dimensional lumen volume measurements from high-resolution computed tomography, while morphometry is acceptable for two-dimensional measurements. The image dataset could be used to validate other developmental three-dimensional segmentation algorithms.

Animals↗
PubMed2004

A comparison of faculty-led small group learning in combination with computer-based instruction versus computer-based instruction alone on identifying simulated pulmonary sounds.

BACKGROUND: Computer-based learning has gained widespread acceptance in medical curricula, but can it replace faculty-led teaching. PURPOSE: To investigate the effectiveness of independent computer-based learning of pulmonary auscultation alone and in combination with faculty-led teaching. METHODS: The first method involved independent computer-based instruction (CBI; Group 1) of 113 second-year medical students. The second method involved a combination of faculty-led instruction and independent CBI (Group 2) of 79 second-year medical students. A pretest-posttest method of assessment was used. RESULTS: The pretest showed recognition rates of 48% for Group 1 and 46% for Group 2, whereas the posttest showed recognition rates of 81% for Group 1 and 88% for Group 2. The posttest clinical correlation scores were identical with both groups scoring 93 percent. CONCLUSIONS: The study demonstrates that student learning of pulmonary auscultation is similar whether a computer-based independent instructional approach is used alone or in combination with faculty-led sessions.

Auscultation↗
PubMed1985

Methodology and clinical experience with computed tomography and a computer-resident stereotactic atlas.

We have developed a computer-resident stereotactic atlas of the human brain that quantitatively defines subcortical structures within anatomical landmarks detected on obliquely reconstructed computed tomography (CT) slices. Horizontal stereotactic atlas sections can be stretched and contracted by polar transformation and labeled by a computer to fit within these CT scan-defined landmarks. The stereotactic coordinates of any substructure on the atlas-labeled CT slice may then be calculated by the computer and expressed in mechanical adjustments on a stereotactic surgical frame located in the operating room. We demonstrate the use of this method in the stereotactic treatment of movement disorders as an augmentation to conventional ventriculography and microelectrode recording.

Aged↗
PubMed1996

Psychology of computer use: XXXV. Differences in computer users' stress and self-concept in college personnel and students.

104 college students and 88 college faculty/staff at a midwestern university completed a questionnaire composed of the Computer Hassles Scale, a measure of computer users' stress, somatization/anxiety items from the Symptoms Checklist-90, a measure of stress reactions, and the Revised Personal Attribute Inventory, a measure of self-concept. Correlations indicated that for students there was a significant negative relationship between computer users' stress and self-concept (r = -.30), while for faculty/staff there was a significant positive relationship (r = .28). Regression analyses showed that self-concept moderated the relationship between computer users' stress and stress outcomes for only the faculty-staff sample. The moderator effect was interpreted using Linville's 1987 "buffering hypothesis," which suggests that persons with higher scores on self-concept are less prone to experience stress-related outcomes like somatization/anxiety symptoms.

Adult↗
PubMed1996

Psychology of computer use: XXXIX. Prevalence of computer anxiety in British managers and professionals.

The prevalence of computer anxiety among British managers and professionals was investigated. Questionnaire data were obtained from a sample of 235 British managers and professionals. Prevalence was defined as the percentage of individuals in the sample with scores above the midpoint on the computer-anxiety scale. A prevalence rate of 21.3% was found. The prevalence among women was double that among men. This rate is considered very high and may have significant negative effects on productivity or ability to adapt to new computer-based technology. Further, the results imply that scales assessing constructs relevant to rapidly changing issues such as computers need to be constantly updated.

Adaptation, Psychological↗
PubMed2005

TETCORR: a computer program to compute smoothed tetrachoric correlation matrices.

Although many programs exist for computing tetrachoric correlations, these programs typically lack one or more of the following features: (1) efficient processing of a large number of variables and computing of a matrix of coefficients; (2) a matrix-smoothing capability; (3) an accurate, reliable computing algorithm; (4) the ability to handle missing data; and (5) nominal cost. TETCORR, which combines an algorithm developed by Brown (1977) with starting values obtained from Divgi (1979a) for more efficient computation, was created to address these and other user concerns.

Algorithms↗
PubMed1994

A new fiducial alignment system to overlay abdominal computed tomography or magnetic resonance anatomical images with radiolabeled antibody single-photon emission computed tomographic scans.

BACKGROUND: The use of computed tomography (CT) or magnetic resonance (MR) to overlay or register uptake patterns displayed by single-photon emission computed tomography (SPECT) with specific underlying anatomy has the potential to improve image interpretation and decrease diagnostic reading errors. The authors have developed a method that will allow the selection of a region of interest on MR or CT images that correlates with SPECT antibody images from the same patient. This method was validated first in phantom studies and subsequently was used on three patients with suspected colorectal carcinoma. METHODS: Two patients were injected with the technetium-99m-labeled 88BV59 immunoglobulin G human antibody, and the third patient was injected with the iodine-131-labeled 16.88 immunoglobulin M human antibody. CT or MR scans were obtained before antibody infusion, and subsequent SPECT scans were obtained on the first or fourth day after infusion. A customized body cast with landmarks was used for each patient during the CT, MR, and SPECT scans to match slice positions for all scanning modalities. Corresponding fiducial landmarks were identified on axial images. A computer graphics program was written to match and overlay corresponding landmarks for each imaging modality. The image registration accuracy was measured by comparing fiducial marker separations (center to center) on the registered scans. This separation uncertainty was 1-2 mm for CT-MR and 3-4 mm for CT-SPECT phantom studies. RESULTS: For patient studies, the fiducial alignment uncertainty was 3-4 mm for axial CT-SPECT and MR-SPECT images, and 6-8 mm for sagittal CT-SPECT and MR-SPECT images. The accuracy of the anatomic alignment of the patient and image registration system was +/- 1 cm in the medial-lateral axis and +/- 2 cm in the cranial-caudal direction. CONCLUSIONS: This type of image analysis may resolve uncertainties with the anatomic correlation of SPECT images that otherwise may be regarded as questionable when SPECT is used alone for radioimmunodiagnosis.

Colorectal Neoplasms↗
PubMed1984

The design of a computer-assisted education system using a CT scanner computer.

The minicomputer that is part of a commercial CT scanner has been used to develop a general purpose computer-assisted education system. This allows instruction in radiology using the CT computer already installed in the radiology department. The computer software was designed as a course interpreter, allowing the courses themselves to be written in English. Images and educational text are stored on separate disk files and displayed by the interpreter.

Computer-Assisted Instruction↗
PubMed1990

[Digital computer arthrometry of the upper ankle joint using a personal computer. A new procedure].

The digital computerarthrometry (DCAM) was developed as a very cost-effective device to calculate the pathologic angles of injured joints. The joint's data are captured by a frame grabber-board installed in a personal computer after takeover from the X-rays by a video camera. Measurements are performed using a commercially available software package which displays the X-ray-photograph on a separate screen besides the one used to manipulate the computer. With this system the calculations of angles and distances of the injured joints are performed with considerably higher precision as it could be done before. As a further possibility bone density measurements may be done from the X-rays as it had been tried to before computers could be used. Our first results seem to present our system as an alternative to the costly workstations, that had to be used until now.

Ankle Joint↗
PubMed1993

Non-discrete biomolecular computing: an approach to computational complexity.

General principles of information processing at the molecular level inherent in simple biological and biomolecular entities can be used to elaborate essentially new non-discrete information-processing devices. These principles are: giant parallelism of information processing; processing mechanisms based on complicated non-linear dynamics; high efficiency of information transformations; considerable behavioral complexity of computational (pseudoelementary) primitives; and the possibility of variation and evolution of the molecular components of information-processing devices, including the possibility of evolutionary learning. Problems of high computational complexity are currently of great practical importance. Non-discrete biomolecular information-processing devices seem to be able to solve effectively some classes of problems of high computational complexity.

Biomedical Engineering↗
PubMed2006

The influence of computed tomography motion artifacts on computer-assisted surgery.

PURPOSE: Motion artifacts can significantly deteriorate the precision of a computer-assisted surgical intervention because they destroy the isometric representation of tomographic pictures. In the context of a study, the influence of typical motion artifacts on the precision of markerless laser registration in image-guided oral and maxillofacial surgery was analyzed, and quality factors for evaluation of the isometry of a computed tomography (CT) dataset were determined. PATIENTS AND METHODS: Twenty patients underwent markerless registration, the precision being determined by means of intraoral evaluation markers. Then the 20 CT datasets were used for simulation of a typical motion artifact. The precision of the overlay of the dataset was checked again on the navigation workstation, in absence of the patient. The navigation system used was the Surgical Segment Navigator SSN++ (University of Heidelberg, Heidelberg, Germany). RESULTS: The motion artifacts reduced the average patient registration from 1 to 4 mm. Quality factors for the isometry of a CT dataset were: the volume enclosed between the soft tissue mantles of the preoperative CT dataset and the intraoperative laser scan dataset, as well as the orientation of the normal vectors on the 3-dimensional reconstruction of the CT dataset. CONCLUSION: The isometry of a CT dataset should always be checked before performance of a computer assisted surgical intervention because anisometric datasets result in inaccurate patient registration and navigation.

Artifacts↗
PubMed2003

Computer-assisted simulations in orthodontic diagnosis and the application of a new cone beam X-ray computed tomography.

Computational simulations which include three-dimensional (3-D) image processing and biomechanical calculations should provide useful information to our research and orthodontic clinic as a clinical tool defined as 'thinking'. In this review, 1) biomechanical simulations applied to predict the mandibular growth; 2) mathematical models of virtual bone cells and 3) 3-D images and solid model simulations for surgical planning are introduced. In biomechanical simulation, biting force, electromyographic (EMG) activity and cephalograms of 32 subjects were applied. Computational results of mathematical model were compared with actual bone growth in a rat. Three-dimensional image and solid model of 14 patients were utilized for their treatment planning. From the results, several concepts of our simulations were confirmed: 1) reaction forces generated by masticatory muscles at the condyle control the direction of mandibular growth; 2) some mathematical models have the possibility to describe the process of bone growth; 3) 3-D image processing software and solid models are necessary for diagnosis and planning of orthognathic surgery. We also believe that the orthodontists can more accurately predict the affects of surgical procedures and orthodontic tooth movement using the new cone beam X-ray computed tomography (CT) (CB MercuRay; Hitachi Medico Technology, Tokyo, Japan) and its advanced application software.

Animals↗
PubMed2003

Blood compatible design of a pulsatile blood pump using computational fluid dynamics and computer-aided design and manufacturing technology.

Thrombus formation is a critical issue when designing a long-term implantable left ventricular assist system (LVAS). Fluid dynamic characteristics of blood flow are one of the main factors that cause thrombus formation. In this study, we optimized the fluid dynamics of a sac blood pump in our LVAS to ensure minimization of shear-related blood damage that could lead to thrombus formation. A pump housing and a sac chamber were designed with computer-aided design (CAD) software, and fluid dynamics were estimated by computational fluid dynamic (CFD) analysis. We adopted distribution of CFD results for qualitative evaluation, and we also tried to estimate normalized index of hemolysis (NIH) from the results of CFD analysis as a quantitative index of optimization for geometry of the blood pump chamber. A prototype model of the optimized blood pump was made using a three-axis computer machine tool by whittling pieces of nonfoamed polyurethane. Shear stress and theoretical NIH in the redesigned model were lower than those in the first model. Area of flow stagnation that was observed in the first model was not seen in the redesigned model. The results demonstrate that application of CAD/CAM technology to design an artificial heart contributes to optimizing a blood pump chamber for the purpose of reducing thrombus formation.

Biomedical Technology↗
PubMed2005

Computed tomographic virtual colonoscopy computer-aided polyp detection in a screening population.

BACKGROUND & AIMS: The sensitivity of computed tomographic (CT) virtual colonoscopy (CT colonography) for detecting polyps varies widely in recently reported large clinical trials. Our objective was to determine whether a computer program is as sensitive as optical colonoscopy for the detection of adenomatous colonic polyps on CT virtual colonoscopy. METHODS: The data set was a cohort of 1186 screening patients at 3 medical centers. All patients underwent same-day virtual and optical colonoscopy. Our enhanced gold standard combined segmental unblinded optical colonoscopy and retrospective identification of precise polyp locations. The data were randomized into separate training (n = 394) and test (n = 792) sets for analysis by a computer-aided polyp detection (CAD) program. RESULTS: For the test set, per-polyp and per-patient sensitivities for CAD were both 89.3% (25/28; 95% confidence interval, 71.8%-97.7%) for detecting retrospectively identifiable adenomatous polyps at least 1 cm in size. The false-positive rate was 2.1 (95% confidence interval, 2.0-2.2) false polyps per patient. Both carcinomas were detected by CAD at a false-positive rate of 0.7 per patient; only 1 of 2 was detected by optical colonoscopy before segmental unblinding. At both 8-mm and 10-mm adenoma size thresholds, the per-patient sensitivities of CAD were not significantly different from those of optical colonoscopy before segmental unblinding. CONCLUSIONS: The per-patient sensitivity of CT virtual colonoscopy CAD in an asymptomatic screening population is comparable to that of optical colonoscopy for adenomas > or = 8 mm and is generalizable to new CT virtual colonoscopy data.

Adenomatous Polyps↗
PubMed1994

Massively parallel computers for 3D single-photon-emission computed tomography.

Since the introduction of the expectation-maximization (EM) algorithm for generating maximum-likelihood (ML) and maximum a posteriori (MAP) estimates in emission tomography, there have been many investigators applying the ML method. However, almost all of the previous work has been restricted to two-dimensional (2D) reconstructions. The major focus and contribution of this paper is to demonstrate a fully three-dimensional (3D) implementation of the MAP method for single-photon-emission computed tomography (SPECT). The 3D reconstruction exhibits an improvement in resolution when compared to the generation of the series of separate 2D slice reconstructions. As has been noted, the iterative EM algorithm for 2D reconstruction is highly computational; the 3D algorithm is far worse. To accommodate the computational complexity, we have extended our previous work in the 2D arena and demonstrate an implementation on the class of massively parallel processors of the 3D algorithm. Using a 16000 processor MasPar machine, the algorithm is demonstrated to execute at 1.24 s/EM iteration for the entire 64 x 64 x 64 cube of 64 planar measurements obtained from the Siemens Orbiter rotating camera operating in the high-resolution mode.

Algorithms↗
PubMed1998

Toward clinical end-user computing: programmable order protocols for efficient human computer interaction.

We have developed and implemented an efficient method of managing routine patient care information as a programmable group order protocol. The purpose of protocol is to minimize a labor-intensive manual computer interaction by grouping clinically related routine orders as a single entity, thus to greatly speed up the time taken for manual entry such as keyboard stroke and/or mouse clicking. User programmability is added to facilitate insertion, deletion and update of order items to be a locally independent operation. A sequence of menu screen is also programmable when a change of standard operation is needed. Department specific order protocols are classified into four categories to improve user convenience. The degree of efficiency is measured by a number of key strokes and entry time. In most cases the time to enter order protocol with correction is found to take less than one minute with less than five key strokes. The method of order protocol entry clearly demonstrates end-user computing capability so that department specific requirements are resolved without resorting to computer department personnel. Flexibility of managing individual physician specific protocols is also beneficial enough to enhance the morale toward a hospital information system currently in use.

Computer Graphics↗
PubMed2000

Human-computer interactions: can computers improve the way doctors work?

As medicine becomes more complex and the knowledge base expands, the integration of computer systems into clinical practice would appear to be an inescapable necessity rather than an option. The issues of security and reliability have largely been solved by industrial and business applications of computer technology. The larger challenge lies in designing convenient, efficient and acceptable interfaces between the clinician and computer for data input and presentation. In the future, decision making algorithms are likely to assist the clinician in diagnosis and management to a degree that should significantly improve clinical effectiveness.

Decision Making, Computer-Assisted↗