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PubMed1995

Computer-assisted multidimensional atlas for functional stereotaxy.

Functional stereotactic operations are currently performed primarily for medically uncontrollable Parkinson's disease and pain. In contrast to the targets in neuro-oncology, those in functional stereotaxy cannot be represented directly by modern imaging methods. The target co-ordinates must therefore be calculated with the aid of special stereotactic atlases. These are publications in which a model brain has been constructed from autopsy examinations on a number of brains, or the data obtained have been compiled in the form of tables and histograms on which the calculation is then based. The target can then be determined based on the classic stereotactic landmarks and reference lines, such as the anterior commissure (AC), the foramen of Monro (FM), the posterior commissure (PC) or the base line FM-PC or AC-PC and the height of thalamus, taking into account the interindividually different anatomical proportions. Since the computational procedures involve repetitious algorithms, it was obvious that such procedures should be run by a computer program. For the most common stereotactic targets, we have developed a computer program for data storage on the one hand and computation and graphic output on the other. The output can be displayed on the monitor and can also be plotted out on paper or overhead transparency. Calibrating between the program and printer renders a 1:1 reproduction, i.e. the graph can be superimposed directly onto original x-rays or images from computed tomography or nuclear magnetic imaging. The graph can be plotted in the three dimensions of the Cartesian co-ordinate system. An additional dimension can be attained by simultaneously including and plotting the data from different atlases and thus from different authors, including one's own data. In addition to the information capacity which this system offers, it also makes possible a considerable reduction in the time for computing the target while at the same time increasing the reliability.

Algorithms↗
PubMed1993

[3-dimensional imaging diagnosis with a personal computer].

During orthodontic and surgical treatment planning of severe dentofacial deformities, 3D-reconstruction imaging from axial CT-scans could previously only be handled by high-capacity computers in radiological centers. The improved performance of personal computers enables CT-scan data be transferred to a standardized MS-DOS computer. The presented software displays a 3D-reconstruction and secondary reformed vertical slices within seconds on the monitor. The symmetry of the 3D-objects can be evaluated with a freely definable grid. The distance between two different landmarks in the 3D-image can also be measured. Various tools for data manipulation permit surgical treatment simulation. The advantage of 3D-imaging with a personal computer is the user-specified orientation of the software. The off-line computing system permits a high degree of flexibility independent of any computing center.

Cephalometry↗
PubMed2004

[Subjective experience of a computer-assisted cognitive training by patients with schizophrenia].

Cognitive training is an important aim of treatment for patients with schizophrenia. However, computer-based cognitive training is still not widely used, and there are reservations concerning the use of computers in psychiatric treatment. In a multicentre study, 64 patients with schizophrenia were investigated before and after completing a 5-week course of computer-based cognitive training using the program Cogpack. In addition to self-rating of computer anxiety (CARS) and subjective well-being (SWN), patients underwent semistructured interviews evaluating attitudes towards the training. The training was rated as highly acceptable by patients and experienced as very effective. Patients' expectations of possible training effects were largely met. The training ranked high in patients' judgement compared with other treatments received. Besides improvement in cognitive function (primary effect), patients enjoyed the training and reported increased self-esteem and progress in using computers (secondary effects). Computer anxiety scores at onset of treatment did not exceed normal values. After completion of the training, these scores were significantly reduced and subjective well-being significantly increased.

Adolescent↗
PubMed2006

Utilising handheld computers to monitor and support patients receiving chemotherapy: results of a UK-based feasibility study.

GOALS OF WORK: Recent changes in cancer service provision mean that many patients spend a limited time in hospital and therefore experience and must cope with and manage treatment-related side effects at home. Information technology can provide innovative solutions in promoting patient care through information provision, enhancing communication, monitoring treatment-related side effects and promoting self-care. PATIENTS AND METHODS: The aim of this feasibility study was to evaluate the acceptability of using handheld computers as a symptom assessment and management tool for patients receiving chemotherapy for cancer. A convenience sample of patients (n = 18) and health professionals (n = 9) at one Scottish cancer centre was recruited. Patients used the handheld computer to record and send daily symptom reports to the cancer centre and receive instant, tailored symptom management advice during two treatment cycles. Both patients' and health professionals' perceptions of the handheld computer system were evaluated at baseline and at the end of the project. MAIN RESULTS: Patients believed the handheld computer had improved their symptom management and felt comfortable in using it. The health professionals also found the handheld computer to be helpful in assessing and managing patients' symptoms. CONCLUSIONS: This project suggests that a handheld-computer-based symptom management tool is feasible and acceptable to both patients and health professionals in complementing the care of patients receiving chemotherapy.

Adult↗
PubMed1986

Self-help computer conferencing.

Computer conferencing has become popular as an alternative to face-to-face conferencing in many kinds of organizations. Since users can participate at any time, from any terminal, computer conferencing makes communication very convenient, though many find the medium to be impersonal. This paper discusses the potential of computer conferencing to increase the number of people who participate in self-help groups, such as groups to help people lose weight or stop smoking. The kinds of interactions that make for successful self-help groups might be encouraged by a computer-conferencing format, even though there is no direct, face-to-face contact. The results of a trial smoking-cessation program which employed computer conferencing suggest that computer conferencing could play a useful role in health promotion.

Computer-Assisted Instruction↗
PubMed1995

Computational properties of self-reproducing growing automata.

Living organisms perform much better than computers at solving complex, irregular computational tasks, like search and adaptation. Key features of living organisms, identified in the paper as a basis for their success in solving complex problems, are: self-reproduction of cells, flexible framework, and modification. These key features of living organisms are abstracted into a computational model, called growing automata. Growing automata are suited for extremely large computational problems, such as search problems. Growing automata are representatives of soft machines. Soft machines can change their physical structure as opposed to hard machines which have fixed structure. An example of a soft machine is a living organism, an example of a hard machine is an electronic computer. The computational properties of soft and hard machines are analyzed and compared. An analysis of growing automata demonstrates their advantages, as well as their limitations as compared to hard machines.

Computer Simulation↗
PubMed1994

The Staggers Nursing Computer Experience Questionnaire.

This report described the development and initial psychometric testing for an instrument measuring nurses' perceived computer experience. The instrument's theoretical basis was psychometric theory and innovation adoption, specifically innovation use and knowledge. The scored portion of the instrument asks nurses to rate their past or present computer use and knowledge for general computer and HIS applications as well as participation in and knowledge about informatics role activities. A descriptive section of the tool asks nurses to indicate the number of formal courses and college-level computer/informatics courses they have taken. A novice-to-expert scale allows nurses to indicate their overall computer experience. Additionally, nurses list reasons, if any, that they might not use computers often. Content and construct validity were adequate for the instrument. Test-retest reliability indicated beginning reliability for the tool. The SNCEQ provides a reliable and valid measure for assessing nurses' past and present computer experience.

Adult↗
PubMed2006

Human errors and violations in computer and information security: the viewpoint of network administrators and security specialists.

This paper describes human errors and violations of end users and network administration in computer and information security. This information is summarized in a conceptual framework for examining the human and organizational factors contributing to computer and information security. This framework includes human error taxonomies to describe the work conditions that contribute adversely to computer and information security, i.e. to security vulnerabilities and breaches. The issue of human error and violation in computer and information security was explored through a series of 16 interviews with network administrators and security specialists. The interviews were audio taped, transcribed, and analyzed by coding specific themes in a node structure. The result is an expanded framework that classifies types of human error and identifies specific human and organizational factors that contribute to computer and information security. Network administrators tended to view errors created by end users as more intentional than unintentional, while errors created by network administrators as more unintentional than intentional. Organizational factors, such as communication, security culture, policy, and organizational structure, were the most frequently cited factors associated with computer and information security.

Computer Communication Networks↗
PubMed2006

Computer systems analysis of spaceflight induced changes in left ventricular mass.

Circulatory adaptations resulting in postflight orthostasis have frequently been observed in response to space travel. It has been postulated that a decrement in left ventricular mass (LVM) found after microgravity exposure may be the central component in this cardiovascular deconditioning. However, a physiologic mechanism responsible for these changes in the myocardium has not been determined. In this study, we examined the sequential alterations in echocardiographic measured LVM from preflight to landing day and 3 days into the postflight recovery period. In a previous study in returning astronauts we found a comparative 9.1% reduction in postflight LVM that returned to preflight values by the third day of recovery. This data was further evaluated in a systems analysis approach using a well-established advanced computer model of circulatory functioning. The computer model incorporates the physiologic responses to changes in pressures, flows and hydraulics within the circulatory system as affected by gravitational forces. Myocardial muscle progression to atrophy or hypertrophy in reaction to the circulatory load conditions is also included in the model. The integrative computer analysis suggests that these variations in LVM could be explained by simple fluid shifts known to occur during spaceflight and can reverse within a few days after reentry into earth's gravity. According to model predictions, the reductions in LVM found upon exposure to microgravity are a result of a contraction of the myocardial interstitial fluid space secondary to a loss in the plasma volume. This hypothesis was additionally supported by the published ground-based study in which we followed the alterations in LVM and plasma volume in normal subjects in which hypovolemia was induced by simple dehydration. In the hypovolemic state, plasma volume was reduced in these subjects and was significantly correlated with echocardiographic measurements of LVM. Based on these experimental findings and the performance of the computer systems analysis it appears that reductions in LVM observed after spaceflight may be secondary to fluid exchanges produced by common physiologic mechanisms. Reductions in LVM observed after microgravity exposure have been previously postulated to be a central component of spaceflight-induced cardiovascular deconditioning. However, a recent study has demonstrated a return of astronauts' LVM to preflight values by the third day after landing through uncertain mechanisms. A systems analysis approach using computer simulation techniques allows for a dissection of the complex physiologic control processes and a more detailed examination of the phenomena. From the simulation studies and computer analysis it appears that microgravity induced reductions in LVM may be explained by considering physiologic fluid exchanges rather than cardiac muscle atrophy.

Adult↗
PubMed2006

Multi-slice computer tomography of left ventricular function with automated analysis software in comparison with conventional ventriculography.

PURPOSE: To evaluate the accuracy of left ventricular volumetric and functional parameters from multi-slice computed tomography using automated analysis software, and to correlate results with those of invasive left ventriculography. MATERIALS AND METHODS: In 145 consecutive patients (mean age, 61 years+/-12) known or suspected to have coronary artery disease, a 16-channel multi-slice computed tomography (Philips Mx8000 IDT 16) was performed using a standard technique. Using short-axis secondary multi-slice computed tomography reformations, we determined end-diastolic and end-systolic left ventricular volumes and ejection fraction with a commercially available analysis software capable of automated contour detection. Conventional left ventriculography was performed according to standard techniques within the following 24 h. Bland-Altman analysis was performed to calculate the limits of agreement and systematic errors between multi-slice computed tomography and conventional left ventriculography. RESULTS: As determined by computer tomography, mean end-systolic (53+/-29 mL) left ventricular volumes had an acceptable correlation with conventional ventriculography (67+/-50 mL; r=0.74; p<0.001) and mean end-diastolic (119+/-33 mL) left ventricular volumes a poor correlation with conventional ventriculography measurements (154+/-69 mL; r=0.41). Left ventricular ejection fraction (57%+/-14 versus 55%+/-14 for conventional ventriculography; r=0.79) showed a very good correlation (p<0.001). Bland-Altman analysis showed acceptable limits of agreement (+/-9.2% for ejection fraction) without systematic errors. CONCLUSION: The use of a multi-slice computed tomography with an automatic calculation software has a good correlation with conventional ventriculography findings and could accurately assess left ventricular function, but should not be used for ventricular volumes, because of biased estimations.

Cineradiography↗
PubMed2003

Relative en- and exophthalmometry in zygomatic fractures comparing optical non-contact, non-ionizing 3D imaging to the Hertel instrument and computed tomography.

AIM: It is the aim of the present study to introduce non-contact, non-invasive optical 3D imaging to relative exophthalmometry and to compare the resulting data to exophthalmometry values assessed by the Hertel instrument and computed tomography. PATIENTS AND METHODS: 20 patients (3 female, 17 male, 44.4+/-16.6 years) without orbital pathology, who were examined by computed tomography of head and neck for the exclusion of different diseases, and seven patients (1 female, 6 male, 40.1+/-14.4 years), who received routine orbital computed tomography because of zygomatic fractures, were included in the study. Optical 3D images of the facial surface were assessed and Hertel exophthalmometry was carried out to determine the relative globe position. In patients with zygomatic fractures the assessment of optical 3D images and Hertel values was repeated 5 days after surgery. RESULTS: For patients without orbital pathology relative exophthalmometry data were 1.4+/-1.1 mm for the Hertel instrument, 0.9+/-1.0 mm for computed tomography and 0.5+/-0.5 mm for optical 3D imaging. The values for Hertel exophthalmometry and computed tomography did not differ statistically significantly (p(Herteldifferencepreop/CTdifferencepreop)=0.284), while there was a significant difference between Hertel exophthalmometry and optical 3D imaging (p(Herteldifferencepreop/opticaldifferencepreop)=0.008). In the cases of zygomatic fractures, Hertel exophthalmometry revealed less pronounced relative differences in globe position than CT and optical 3D imaging data (Hertel 0.7+/-1.1 mm, CT 1.9+/-1.0 mm, optical 3D imaging 1.9+/-1.0 mm). Postoperatively, relative Hertel exophthalmometry showed an increased value revealing a more pronounced enophthalmos (1.7+/-1.0 mm), while the corresponding value of the optical 3D images decreased as a sign for normalization of the globe position (1.1+/-0.7 mm). CONCLUSION: Because of its reliance on the lateral orbital rims Hertel exophthalmometry can lead to an under- or overestimation of enophthalmos, when soft tissue oedema or a dislocation of the orbital rim are present. The combination of computed tomography as baseline measurement and optical 3D imaging for the follow-up examinations reveal more realistic data in cases of zygomatic fractures. Therefore, they should be preferred to the determination of Hertel values especially in more complex cases.

Adult↗
PubMed2006

Breath-hold single-photon emission tomography and computed tomography for predicting residual pulmonary function in patients with lung cancer.

OBJECTIVE: We sought to evaluate the utility of integrated breath-hold single-photon emission tomography and computed tomography imaging compared with that of simple calculation with the lung segment-counting technique for predicting residual pulmonary function in patients undergoing surgical intervention for lung cancer. METHODS: A prospective series of 22 patients undergoing anatomic lung resection for cancer were enrolled in this study. Postoperative residual forced expiratory volume in 1 second was predicted by measuring the radioactivity counts of the affected lobes or segments to be resected within the entire lungs by placement of regions of interest on single-photon emission tomography and computed tomography images. Residual forced expiratory volume in 1 second was also estimated by using the segment-counting technique. RESULTS: Both predicted values agreed well with postoperative forced expiratory volume in 1 second. Although the residual forced expiratory volume in 1 second predicted by means of single-photon emission tomography and computed tomography correlated well with that predicted by using segment counting, the values were significantly underestimated by the segment-counting technique in 4 outliers with severe emphysema. There were 2 patients with borderline pulmonary functional reserve whose residual forced expiratory volume in 1 second values were predicted more accurately by means of single-photon emission tomography and computed tomography than by using segment counting. CONCLUSION: Integrated breath-hold single-photon emission tomography and computed tomography images allow the accurate prediction of postoperative pulmonary function but without statistical superiority over the simple segment-counting technique. Further study of the usefulness of single-photon emission tomography and computed tomography in patients with severe emphysema and borderline lung function should prove valuable because the segment-counting technique underestimates pulmonary functional reserve in these patients.

Aged↗
PubMed2006

Computer-based education for patients with chronic heart failure. A randomised, controlled, multicentre trial of the effects on knowledge, compliance and quality of life.

OBJECTIVE: To evaluate the effects of a single-session, interactive computer-based educational program on knowledge, compliance and quality of life in heart failure patients with special emphasis on gender differences. METHODS: One hundred and fifty-four patients, mean age 70 years, from five heart failure clinics were randomised to either receiving only standard education (n=72) or standard education and additional computer-based education (n=82). RESULTS: Knowledge was increased in both groups after 1 month with a trend towards higher knowledge (P=0.07) in the computer-based group. The increase in knowledge was significantly higher in the computer-based group after 6 months (P=0.03). No differences were found between the groups with regard to compliance with treatment and self-care or quality of life. The women had significantly lower quality of life and did not improve after 6 months as the men did (P=0.0001). CONCLUSION: Computer-based education gave increased knowledge about heart failure. PRACTICE IMPLICATIONS: Computers can be a useful tool in heart failure education, but to improve compliance a single-session educational intervention is not sufficient. Gender differences in learning and quality of life should be further evaluated.

Adult↗
PubMed2006

Computer-assisted cognitive remediation in schizophrenia: what is the active ingredient?

An emerging body of research has shown that computer-assisted cognitive remediation, consisting of training in attention, memory, language and/or problem-solving, produces improvement in neurocognitive function that generalizes to untrained neurocognitive tests and may also impact symptoms and work functioning in patients with schizophrenia. The active ingredient of these interventions, however, remains unknown as control groups in these studies have typically included few, if any, of the elements of these complex behavioral treatments. This study compared the effects of an extended (12-month), standardized, computer-assisted cognitive remediation intervention with those of a computer-skills training control condition that consisted of many of the elements of the experimental intervention, including hours spent on a computer, interaction with a clinician and non-specific cognitive stimulation. Forty-two patients with schizophrenia were randomly assigned to one of two conditions and were assessed with a comprehensive neuropsychological test battery before and after treatment. Results revealed that cognitive-remediation training produced a significant improvement in working memory, relative to the computers-skills training control condition, but that there was overall improvement in both groups on measures of working memory, reasoning/executive-function, verbal and spatial episodic memory, and processing speed. Taken together, these findings suggest that specific practice in neurocognitive exercises targeted at attention, memory and language, produce improvements in neurocognitive function that are not solely attributable to non-specific stimulation associated with working with a computer, interacting with a clinician or cognitive challenge, but that non-specific stimulation has a salutary effect on neurocognition as well.

Adult↗
PubMed2002

CLiBE: a database of computed ligand binding energy for ligand-receptor complexes.

Consideration of binding competitiveness of a drug candidate against natural ligands and other drugs that bind to the same receptor site may facilitate the rational development of a candidate into a potent drug. A strategy that can be applied to computer-aided drug design is to evaluate ligand-receptor interaction energy or other scoring functions of a designed drug with that of the relevant ligands known to bind to the same binding site. As a tool to facilitate such a strategy, a database of ligand-receptor interaction energy is developed from known ligand-receptor 3D structural entries in the Protein Databank (PDB). The Energy is computed based on a molecular mechanics force field that has been used in the prediction of therapeutic and toxicity targets of drugs. This database also contains information about ligand function and other properties and it can be accessed at http://xin.cz3.nus.edu.sg/group/CLiBE.asp. The computed energy components may facilitate the probing of the mode of action and other profiles of binding. A number of computed energies of some PDB ligand-receptor complexes in this database are studied and compared to experimental binding affinity. A certain degree of correlation between the computed energy and experimental binding affinity is found, which suggests that the computed energy may be useful in facilitating a qualitative analysis of drug binding competitiveness.

Binding, Competitive↗
PubMed1998

Radiologic volumetry on a personal computer with a stereologic method.

RATIONALE AND OBJECTIVES: There is no universally accepted way to estimate organ and tumor volumes, and manual tracing of the outline of an organ or tumor is tedious, time-consuming, and therefore not widely used. The authors developed a stereologic method for estimating organ and tumor volumes with a personal computer and evaluated its accuracy and efficiency with computed tomographic images. MATERIALS AND METHODS: CT images were obtained of a 200-cm3 phantom sphere, a normal liver, a normal spleen, a brain tumor, and a large abdominopelvic tumor. Volumes were estimated with a computer program developed on a personal computer. The estimated volumes were compared with those found with the manual tracing method, which was used as a standard of reference. The time to complete each procedure was recorded. RESULTS: When approximately 200 grid points were used, the volumes estimated with the computer were varied from the reference by 1.9%-4.5%. The volumes ranged from 51 to 2,679 cm3, and the time to estimate these ranged from 42 to 96 seconds. CONCLUSION: Stereologic estimation of organ and tumor volumes from cross-sectional images with a personal computer can be accurate and efficient at a relatively low cost.

Abdominal Neoplasms↗
PubMed1998

Effects of projection geometry and number of projections on accuracy of depth discrimination with tuned-aperture computed tomography in dentistry.

OBJECTIVE: The purpose of this study was to determine the degree to which the number and angular disparity of component projections influence depth discrimination with tuned-aperture computed tomography. STUDY DESIGN: Groups of three tiny steel spheres served as fiducial references on and in four partially edentulous mandibles. Two spheres were attached to the facial and lingual surfaces of each mandible, and the third was fixed in the apical region of an open tooth socket. Errors in estimates of the depth of the apically positioned sphere relative to the other two spheres were determined from three-dimensional tuned-aperture computed tomography reconstructions. These data were compared with actual measurements produced independently with an optical micrometer. Multiple projections required by the tuned-aperture computed tomography reconstruction algorithm were produced from radially symmetric exposures bearing angular disparities of 5, 15, 30, and 45 degrees. The number of symmetrically dispersed projections per tuned-aperture computed tomography reconstruction likewise was varied systematically (2, 4, 8, 12, and 16 projections). These variables were manipulated through the use of a balanced factorial design. Depth estimates were performed by trained observers; the estimates were based on the determination of tuned-aperture computed tomography slices perceived as imaging the respective apical spheres in sharpest focus. Specimen and observer effects were also considered as independent variables. Resulting data were normalized by logarithmic transformation and analyzed statistically by analysis of variance. RESULTS: Significant differences (p < 0.005) were demonstrated for angular disparity and specimen effects, but the number of projections and the effect of the observer were not found to be statistically significant. CONCLUSIONS: In dentistry, angular disparities of 15 degrees or greater should be used when tuned-aperture computed tomography is being applied to diagnostic tasks requiring maximal depth discrimination accuracy.

Algorithms↗
PubMed2002

Multislice spiral computed tomography in diagnosis and staging of pancreatic carcinoma: preliminary experience.

BACKGROUND: Computed tomography has become the modality of choice for preoperative evaluation of patients with suspected pancreatic carcinoma, although some limitations are well known. AIMS: To evaluate use of multislice spiral computed tomography in preoperative assessment of patients with suspected pancreatic carcinoma using volume-rendering as image reconstruction algorithm. PATIENTS: A total of 27 patients with suspected pancreatic carcinoma underwent multislice spiral computed tomography examination. METHODS: All studies were performed on a multislice computed tomography scanner with the following parameters: slice collimation, 1 mm; slice thickness, 1.25 mm; reconstruction interval, 1 mm; scan time, 22-25 sec; mAs, 165. Scans were acquired with a biphasic technique with a 30-sec (pancreatic phase) and a 70-sec (portal venous phase) delay time after start of contrast material injection. Diagnostic confirmation was obtained with surgical exploration, percutaneous biopsy, or with a combination of follow-up imaging studies. RESULTS: Multislice spiral computed tomography yielded correct diagnosis of pancreatic carcinoma in 20 cases (sensitivity, 95%; specificity, 100%). Positive predictive values for resectability and unresectability were 80% and 93.3%, respectively. Three-dimensional volume-rendered images improved diagnostic confidence in the depiction of major vascular structures. Two cases of anomalous origin of hepatic artery were also identified with volume-rendered images. CONCLUSIONS: Multislice technology improves accuracy of spiral computed tomography for diagnosis and staging of pancreatic carcinoma.

Algorithms↗