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PubMed1993

Prediction of treatment temperatures in clinical hyperthermia of locally advanced breast carcinoma: the use of contrast enhanced computed tomography.

PURPOSE: Nineteen patients with locally advanced breast carcinoma were subjected to computed tomography examinations prior to thermoradiotherapy. Pre- and postcontrast computed tomography images were obtained, and tumor contrast enhancement was studied in relation to tissue perfusion, PERF, and steady state temperature, TS, in an attempt to develop an assay for prediction of treatment temperatures in clinical hyperthermia of breast carcinoma. METHODS AND MATERIALS: PERF and TS were calculated from temperature data achieved during the first fraction of the heat treatment regimen. The computed tomography images were subjected to image analysis, and two parameters representing tumor contrast enhancement were calculated from the computed tomography numbers; the absolute increase in mean attenuation, delta N, and the fraction of the postcontrast attenuation values that was higher than the mean precontrast attenuation value, F+C. RESULTS: delta N and F+C were clearly correlated to each other. The two parameters differed considerably among the patients, showing that the accumulation of contrast medium was higher in some tumors than in others. Tumor contrast enhancement increased with increasing PERF, suggesting that the accumulation of contrast medium in the tumors was determined mainly by the effective tissue perfusion. There was also a clear correlation between tumor contrast enhancement and TS. The tumors showing a high accumulation of contrast medium were more difficult to heat than those showing a low accumulation. CONCLUSION: The results indicate that contrast enhanced computed tomography images may give information about the treatment temperatures that can be achieved in clinical hyperthermia of breast carcinoma. The computed tomography images may possibly be used to predict those tumors that can be heated to therapeutic temperatures.

Body Temperature↗
PubMed1995

A portable software tool for computing digitally reconstructed radiographs.

PURPOSE: To develop a portable software tool for fast computation of digitally reconstructed radiographs (DRR) with a friendly user interface and versatile image format and display options. To provide a means for interfacing with commercial and custom three-dimensional (3D) treatment planning systems. To make the tool freely available to the Radiation Oncology community. METHODS AND MATERIALS: A computer program for computing DRRs was enhanced with new features and rewritten to increase computational efficiency. A graphical user interface was added to improve ease of data input and DRR display. Installer, programmer, and user manuals were written, and installation test data sets were developed. The code conforms to the specifications of the Cooperative Working Group (CWG) of the National Cancer Institute (NCI) Contract on Radiotherapy Treatment Planning Tools. RESULTS: The interface allows the user to select DRR input data and image formats primarily by point-and-click mouse operations. Digitally reconstructed radiograph formats are predefined by configuration files that specify 19 calculation parameters. Enhancements include improved contrast resolution for visualizing surgical clips, an extended source model to stimulate the penumbra region in a computed port film, and the ability to easily modify the CT numbers of objects contoured on the planning computed tomography (CT) scans. CONCLUSIONS: The DRR tool can be used with 3D planning systems that lack this functionality, or perhaps improve the quality and functionality of existing DRR software. The tool can be interfaced to 3D planning systems that run on most modern graphics workstations, and can also function as a stand-alone program.

Radiographic Image Enhancement↗
PubMed1991

The acute abdomen: the role of computer-assisted diagnosis.

CAD has been used in over 20,000 patients in an Accident and Emergency Department. Structured documentation has replaced normal case notes and a patient record is created which includes investigations and management. A copy of the documentation acts as an immediate communication to the general practitioner. The information is held on a computer and is readily accessed to produce feedback and to allow audit of any number of parameters. The results show that an improvement in diagnostic accuracy and a reduction in admissions and unnecessary laparotomies continues over 15 years. Problems have occurred; some are inherent to the system and some have been minimized as a result of a series of studies. The savings in terms of finance and facilities are considerable and the cost is small in comparison as the programs are available and the cost of hardware has diminished. It is concluded that documentation is essential. This allows the more accurate collection of information, permits analysis, acts as a method of communication and creates a detailed patient record. The use of this part of the CADA system produces a considerable improvement in the parameters used to assess satisfactory patient management. The computer diagnostic program produces a higher level of diagnostic accuracy than that obtained by doctors who are not using the system. It does not normally exceed the accuracy of the doctors who are using the structured documentation and entering the information into the computer. Other mathematical models might lead to an improvement, particularly if they were based on the diagnostic process used by a senior clinician. The method of entry of information could be facilitated by modern technology, including light pens or word sensitive computers. This would reduce the time required for completion of the documents. A number of possible improvements in the CADA system are reported and some have been studied in detail with little evidence of significant change. The computer part of the system has an educational value and presents a stimulating challenge to the junior hospital staff seeing the patient for the first time in the Accident and Emergency Department. Rapid feedback is possible and advantageous. Possibly the greatest value of the computer is in the analysis of the value of clinical features in diagnosis, which has not been easy in the past. It has also allowed precise assessment of the value of investigations in the diagnosis of patients with a suspected disease, which leads to more appropriate management and the saving of facilities.(ABSTRACT TRUNCATED AT 400 WORDS)

Abdomen, Acute↗
PubMed2004

Computer-mediated intervention to prevent drug abuse and violence among high-risk youth.

This research evaluated a computer-mediated intervention for preventing drug abuse and violence. Research participants were economically disadvantaged youth, defined as early adolescents from households with family incomes below the Federal poverty line. Based on cognitive-behavioral skills approaches shown effective in past research, computer intervention was compared with conventionally delivered intervention in a pretest-posttest, control group design. Outcome findings revealed that youth assigned to the computer or conventional intervention arms achieved more positive pretest-to-posttest gain scores than youth in the control arm on several variables. These variables were: how youth regarded people who used drugs, strategies for avoiding trouble, and ways for controlling their tempers. One item, the ability to refuse drug offers, favored youth in the conventional intervention arm over those in the computer or control arms. Combined with prior work on computer-delivered interventions, data from this study lend added support to the viability of computer approaches for preventing drug abuse, violence, and other problem behavior among early adolescent youth.

Adolescent↗
PubMed2006

Physical limits of computation and emergence of life.

The computational process is based on the activity linking mathematical equations to a materialized physical world. It consumes energy which lower limit is defined by the set of Planck's values, i.e. by the physical structure of the Universe. We discuss computability from the quantum measurement framework. Effective quantum computation is possible via the maintenance of a long-living cold decoherence-free internal state, which is achieved by applying error-correction commands to it and by screening it from thermal fluctuations. The quantum Zeno effect enables coherent superpositions and entanglement to persist for macroscopic time intervals. Living systems maintain coherent states via realization of their own computing programs aiming them to survive and develop, while their non-computable behavior corresponds to a generative power that arises beyond combinatorial capabilities of the system. Emergence of life brings in the Universe a creative activity that overcomes the limits of computability.

Animals↗
PubMed2006

Computer-aided vs. tutor-delivered teaching of exposure therapy for phobia/panic: randomized controlled trial with pre-registration nursing students.

BACKGROUND: Exposure therapy is effective for phobic anxiety disorders (specific phobias, agoraphobia, social phobia) and panic disorder. Despite their high prevalence in the community, sufferers often get no treatment or if they do, it is usually after a long delay. This is largely due to the scarcity of healthcare professionals trained in exposure therapy, which is due, in part, to the high cost of training. Traditional teaching methods employed are labour intensive, being based mainly on role-play in small groups with feedback and coaching from experienced trainers. In an attempt to increase knowledge and skills in exposure therapy, there is now some interest in providing relevant teaching as part of pre-registration nurse education. Computers have been developed to teach terminology and simulate clinical scenarios for health professionals, and offer a potentially cost effective alternative to traditional teaching methods. OBJECTIVE: To test whether student nurses would learn about exposure therapy for phobia/panic as well by computer-aided self-instruction as by face-to-face teaching, and to compare the individual and combined effects of two educational methods, traditional face-to-face teaching comprising a presentation with discussion and questions/answers by a specialist cognitive behaviour nurse therapist, and a computer-aided self-instructional programme based on a self-help programme for patients with phobia/panic called FearFighter, on students' knowledge, skills and satisfaction. DESIGN: Randomised controlled trial, with a crossover, completed in 2 consecutive days over a period of 4h per day. PARTICIPANTS: Ninety-two mental health pre-registration nursing students, of mixed gender, age and ethnic origin, with no previous training in cognitive behaviour therapy studying at one UK university. RESULTS: The two teaching methods led to similar improvements in knowledge and skills, and to similar satisfaction, when used alone. Using them in tandem conferred no added benefit. Computer-aided self-instruction was more efficient as it saved teacher preparation and delivery time, and needed no specialist tutor. CONCLUSION: Computer-aided self-instruction saved almost all preparation time and delivery effort for the expert teacher. When added to past results in medical students, the present results in nurses justify the use of computer-aided self-instruction for learning about exposure therapy and phobia/panic and of research into its value for other areas of health education.

Analysis of Variance↗
PubMed2004

Epidemiology of musculoskeletal disorders among computer users: lesson learned from the role of posture and keyboard use.

Reports in the scientific literature and lay press have suggested that computer users are at increased risk of upper extremity musculoskeletal disorders (MSDs). Early studies often found elevated rates of MSD outcomes among keyboard users when compared to non-users. Attention soon focused on specific aspects of keyboard work that might be responsible for the observed rate increase. In this review, the epidemiological evidence examining associations between MSD outcomes and computer user posture and keyboard use intensity (hours of computer use per day or per week) are examined. Results of epidemiological studies of posture and MSD outcomes have not been entirely consistent. Reasons for the inconsistency in results include cross-sectional study design (with possible failure to assure that measured exposure preceded health effect), imprecision of posture measures used, and difficulties involved in analyzing multiple related variables. Despite the inconsistencies, it appears from the literature that posture is an independent risk factor of modest magnitude for MSDs among computer users. It appears that lowering the height of the keyboard to or below the height of the elbow and resting the arms on the desk surface or chair armrests is associated with reduced risk of neck and shoulder MSDs. Results of epidemiological studies examining computer use (hours keying per day or per week) are more consistent than those examining posture, although some inconsistency is observed. Reasons for the inconsistency include possible selective survival bias resulting from cross-sectional study design, differences in exposure categorization, and possible interaction with other exposure variables. Overall, the literature shows that daily or weekly hours of computer use is more consistently associated with hand and arm MSDs than with neck and shoulder MSDs.

Computers↗
PubMed2004

A new computer-assisted method for measuring the tibio-femoral angle in patients with osteoarthritis of the knee.

OBJECTIVE: The purpose of this study was to evaluate the inter- and intraobserver variability in measuring the tibio-femoral angle using our new computer-assisted method, and to compare it with a conventional manual method. METHODS: Radiography of all patients of osteoarthritis of the knee in outpatient were performed with standing on both legs, and with conventional antero-posterior weight bearing view of the knee fully extended. Three examiners measured the tibio-femoral angle with the computerized method in 52 subjects with osteoarthritis (73 knees). The tibio-femoral angle was measured using a computer-assisted method in which the observer must visually determine and select eight points on the margins of the femur and tibia on a radiographic image displayed on a computer monitor. The inter- and intraobserver Intra-class correlation (ICC) was analyzed. RESULTS: The interobserver mean correlation of computer-assisted method was 0.970 with a mean difference of 0.38 degrees (S.D. 1.125 degrees). The intraobserver mean ICC of computer-assisted method was 0.973, with a mean difference of 0.16 degrees (S.D. 1.12 degrees). An analysis of the difference between conventional methods and our new system showed a mean ICC of 0.922, with an intersystem mean difference of 0.295 degrees (S.D. 1.82 degrees). CONCLUSION: Our computer-assisted method of measuring the tibio-femoral angle was simple, easy, and quick, and should be considered as an alternate method for measurement.

Adult↗
PubMed2005

Virtual-designed and computer-milled implant abutments.

Computer-designed and -generated implant abutments will fundamentally change the present restorative protocols for implant dentistry. Standard implant prosthetic techniques rely on implant level impressions and costly casting technology for component fabrication. Many dentists are uncomfortable making implant level impressions and resort to time-consuming conventional techniques of intraoral abutment preparation or do not offer implants as a treatment alternative. Implant abutments generated by computer-aided design and computer-aided manufacturing (CAD/CAM) are more precise than those created using traditional casting technology. This increased accuracy has specific application to implant dentistry, where precision of components may affect implant longevity, prosthetic success, and ease of restoration. Three current CAD/CAM implant abutment systems are reviewed, including an innovative digital system which eliminates the need to make implant level impressions. After placing an encoded healing abutment, an impression is made at the healing abutment level. The resulting cast is optically scanned and, using a CAD/CAM system, a patient specific definitive abutment is created. The encoded healing abutment is not removed until delivery of the abutment and final prosthesis. The ease and precision of making implant impressions at the healing abutment level, followed by patient-specific computer-generated abutments presents several benefits: restorative dentists rely less on conventional dental techniques to restore implants, inaccuracies of casting technology are virtually eliminated, laboratory technicians are freed to concentrate on higher level activities, and ultimately dentists are more likely to embrace implants as a preferred treatment option for their patients. This cutting edge technology of computer-assisted implant impressions and computer-generated abutments will likely replace traditional implant restorative protocols and become the standard for implant dentistry in the foreseeable future.

Computer-Aided Design↗
PubMedDate not supplied

Computational gestalts and perception thresholds.

In 1923, Max Wertheimer proposed a research programme and method in visual perception. He conjectured the existence of a small set of geometric grouping laws governing the perceptual synthesis of phenomenal objects, or "gestalt" from the atomic retina input. In this paper, we review this set of geometric grouping laws, using the works of Metzger, Kanizsa and their schools. In continuation, we explain why the Gestalt theory research programme can be translated into a Computer Vision programme. This translation is not straightforward, since Gestalt theory never addressed two fundamental matters: image sampling and image information measurements. Using these advances, we shall show that gestalt grouping laws can be translated into quantitative laws allowing the automatic computation of gestalts in digital images. From the psychophysical viewpoint, a main issue is raised: the computer vision gestalt detection methods deliver predictable perception thresholds. Thus, we are set in a position where we can build artificial images and check whether some kind of agreement can be found between the computationally predicted thresholds and the psychophysical ones. We describe and discuss two preliminary sets of experiments, where we compared the gestalt detection performance of several subjects with the predictable detection curve. In our opinion, the results of this experimental comparison support the idea of a much more systematic interaction between computational predictions in Computer Vision and psychophysical experiments.

Animals↗
PubMed2006

Computer-based training for safety: comparing methods with older and younger workers.

INTRODUCTION: Computer-based safety training is becoming more common and is being delivered to an increasingly aging workforce. Aging results in a number of changes that make it more difficult to learn from certain types of computer-based training. Instructional designs derived from cognitive learning theories may overcome some of these difficulties. METHODS: Three versions of computer-based respiratory safety training were shown to older and younger workers who then took a high and a low level learning test. RESULTS: Younger workers did better overall. Both older and younger workers did best with the version containing text with pictures and audio narration. DISCUSSION: Computer-based training with pictures and audio narration may be beneficial for workers over 45 years of age. IMPACT ON INDUSTRY: Computer-based safety training has advantages but workers of different ages may benefit differently. Computer-based safety programs should be designed and selected based on their ability to effectively train older as well as younger learners.

Adult↗
PubMed2005

Educational interventions--computers for delivering education to children with respiratory illness and to their parents.

Educational interventions for children with asthma can result in both clinical and psychological improvements. However, traditional education programs have been hampered by lack of resources and doubts concerning long-term benefits. Researchers have looked to computer technology to overcome some of these obstacles and respiratory conditions have been the focus for a number of educational computer programs. Computer education packages should have a robust theoretical basis. Many programs aim to improve children's confidence, self-esteem and feelings of control, all of which are linked to compliance and positive health behaviours. The specific skills and knowledge needed for effective self-management also need to be taught in order to equip the child for future independent self-care. Programs tend to be either a stand-alone game, promoting self-regulation and practicing of skills, or an internet-enabled package, which may provide a link to their healthcare provider and/or other people with a similar condition. Computer technology is flexible, can be tailored to individuals' information needs, provides ongoing educational support and promotes active learning. However, there can be problems around accessibility, both in terms of computer ownership and technological literacy. Furthermore, internet sites are largely unregulated and of variable quality. It is essential that educational computer interventions are evidence-based and rigorously evaluated to identify who will benefit most from these packages.

Adolescent↗
PubMed2003

Computer-automated quantification of plus disease in retinopathy of prematurity.

BACKGROUND: In some cases of retinopathy of prematurity (ROP), it difficult to determine with certainty whether plus disease is present or absent. We have developed a computer program that captures digital images from a video-indirect ophthalmoscope, identifies and traces the major posterior pole blood vessels, measures the dilation and tortuosity of each vessel, and calculates whether or not an eye has plus disease. Our purpose was to determine the accuracy of the computer program in comparison with two masked examiners. METHODS: A representative sample of posterior pole images from 20 premature infants, 10 normal and 10 representing various degrees of dilation and tortuosity, was extracted from our video database and analyzed by the computer program as well as by two masked examiners experienced in the diagnosis of ROP. The standard photograph from the Cryotherapy for ROP study, representing the minimum degree of dilation and tortuosity required for plus disease, was also digitized, analyzed, and used as a numeric comparison for the automated determination of plus disease. RESULTS: Of the five images determined to have plus disease by both examiners, four were calculated to have plus disease by the computer program (80% sensitivity). Of the 11 images without plus disease, 10 were calculated not to have plus disease by the computer program (91% specificity). CONCLUSIONS: Our computer program has very good sensitivity and specificity compared with masked examiners' determination of the presence or absence of plus disease. Automated analysis of dilation and tortuosity of posterior pole blood vessels has the potential to remove subjectivity from the determination of plus disease.

Diagnosis, Computer-Assisted↗
PubMed1999

The role of computed tomography with contrast and small bowel follow-through in management of small bowel obstruction.

BACKGROUND: In a significant percentage of patients, radiologic evaluation other than plain abdominal films are required to confirm or exclude the presence of small bowel obstruction. METHODS: Over a 1-year period, 55 patients had both computed tomography and small bowel follow-through studies. Patients were classified as having (1) paralytic ileus, (2) low-grade obstruction, (3) high-grade obstruction, or (4) complete mechanical obstruction. The gold standard for diagnosis was celiotomy in 42 patients and clinical follow-up in 13 patients. RESULTS: Thirty-six out of 42 patients had proven intestinal obstruction at the time of celiotomy. Computed tomography identified 32 out of the 36 high-grade and complete mechanical obstructions. Computed tomography was superior to small bowel follow-through in identifying masses, malignancies, and features of strangulation. Small bowel follow-through correctly identified "insignificant obstructions" when contrast reached the cecum within 4 hours in 18 of 19 patients. CONCLUSIONS: In patients with equivocal findings of small bowel obstruction, computed tomography should be used initially and then small bowel follow-through if computed tomography is not diagnostic. Computed tomography was superior in this study for detecting the cause of the intestinal obstruction and presence of strangulation.

Adolescent↗
PubMed1999

Computed tomography of the sternum and mediastinum after median sternotomy.

BACKGROUND: Computed tomography is used in our hospital to diagnose complications after median sternotomy, but its efficiency is unknown. Nor is the computed tomographic appearance of normal healing of a median sternotomy known. Computed tomography was evaluated for its ability to diagnose mediastinitis and sternal dehiscence, and a reference material of normally healing median sternotomies was created. METHODS: In a prospective study, 20 patients with a normally healing median sternotomy were examined 1 week, 1 month, 3 months, and 6 months after operation. In a retrospective study, 87 scans from 65 patients that were made because a postoperative complication was suspected were reviewed. RESULTS: In the prospective study, all patients had clinically uneventful healing. None of the computed tomographic scans showed radiologic signs of healing at 3 months. At 6 months, half of the patients had healed completely. In the retrospective study, 49 scans were performed on suspicion of infection; 7 of them indicated mediastinitis, 2 were false-positive, while mediastinitis was present in a total of 16 of the scans. Thirty-eight scans were made because of sternal pain or suspected dehiscence; after 21 of the scans, recovery was uneventful, and in 11, the definite diagnosis was dehiscence or pseudarthrosis. CONCLUSIONS: Clinical healing of the sternotomy does not correlate with the computed tomographic image. Computed tomography is not a sensitive tool for diagnosing mediastinitis, and in patients with sternal pain, it adds little information.

Adult↗
PubMed1995

Initialization of warfarin dosages using computer modeling.

OBJECTIVE: Software incorporating warfarin pharmacokinetics and pharmacodynamics, as well as a Bayesian regression method, was evaluated for accuracy in predicting steady-state dosages of warfarin during initialization of anticoagulation therapy. DESIGN: A cohort study was used to compare computer predictions with physician-determined doses during a retrospective chart review of 42 patients. PATIENTS: Forty-two patient charts were selected for monitoring anticoagulation initialization therapy. Of the 42 patients reviewed, 22 were excluded on the following bases: uncontrolled congestive heart failure; ongoing treatment with medications that interfered with warfarin metabolism or displaced warfarin from protein binding sites; recent treatment with fresh frozen plasma or vitamin K; or any bleeding disorders, sepsis, malabsorption or significant changes in liver and/or renal function. MAIN OUTCOME MEASURES: Using physician-determined International Normalized Ratios (INRs) as target levels for the software, the number of INR feedbacks needed to stabilize blood drug levels during initialization were compared between physicians and computer forecasting. Population parameters and sequentially measured INRs were used for evaluation. RESULTS: Current oral anticoagulation protocols require significantly more measured INRs than computer forecasting to achieve steady-state dosages (9.5 v 4.4, respectively, p < 0.01). Physicians showed a statistically significant pattern of underdosing patients (4.3 v 1.7 subtherapeutic INRs, respectively, p < 0.01). Computer predictions tended to overdose patients but did not significantly increase the number of supratherapeutic INRs. This study showed that five INR inputs consistently gave accurate steady-state dosage predictions, and in many ways computer modeling was more effective than clinician-determined steady-state dosing in warfarin initialization. CONCLUSIONS: Computer modeling provides a reliable means of predicting initialization dosages for warfarin anticoagulation therapy with five INR inputs and therefore has merit in the clinical setting if used with sound clinical judgment.

Adult↗
PubMed2003

Comparison of three computer methods of sperm head analysis.

OBJECTIVE: Analysis of sperm heads using three different computer morphometrical tools and experimental conditions to find a more reliable and secure strategy among them. DESIGN: Controlled experiments on sperm morphology analysis from volunteers. SETTING: Laboratory of microscopy and imaging processing. PATIENT(S): Ten human semen samples donated by different zoospermic men. INTERVENTION(S): Semen samples were collected by masturbation after > or =72 hours of abstinence. MAIN OUTCOME MEASURE(S): Spermatozoon head morphology was compared by the use of different video-microscopy systems, three computer programs, and various staining conditions and manipulation by different operators. Nonbiological material in the form of latex beads was also used. RESULT(S): The data obtained suggest that the semiautomatic computer program is the most reliable and secure method for performing sperm analysis, besides the fact that it is a fast process compared with manual methods. CONCLUSION(S): Computer systems of sperm analysis should incorporate a step of interactive object identification to work properly, allowing the operator to confirm or correct possible computer misidentification. The latex beads were used to confirm the capability of all three computer programs to correctly evaluate nonbiological material.

Automation↗
PubMed1997

Computer versus manual measurement of ST-segment deviation.

Total ST scores (sum of absolute deviations in all 12 electrocardiographic [ECG] leads) have been used for research purposes to estimate total ischemic burden and to predict reperfusion after thrombolytic therapy. Computerized monitoring systems are capable of measuring ST deviation to the 10-microV level, whereas humans are incapable of such precise resolution. The purpose of this study was to compare computer versus manual ST scores in 12-lead ECGs exhibiting ischemia and to compare interrater reliability of manual measurements between two experts. A total of 58 subjects with 100 microV or more ST deviation in one or more leads during percutaneous transluminal coronary angioplasty balloon inflation were selected for analysis. ST measurements were made at J + 80 ms, using the isoelectric line as a reference, and summed across all 12 leads. Manual measurements were made to a minimum of 50 microV by two independent reviewers blinded to the computer scores. Total ST scores were compared using paired t-tests, and Pearson coefficients were used to test the correlations. A high correlation was observed between the manual and computer measurements (r = .96, P < .00) and between the two reviewers (r = .96, P < .00). A high degree of interrater reliability is possible with manual measurements of ST deviation. Computer measurements are consistently greater than manual measurements, presumably because humans "round down" to the nearest 50 microV. As such, computers may detect ischemia that is missed by humans. However, computer and manual measurements of ST deviation should not be mixed when used as a variable for research.

Electrocardiography, Ambulatory↗