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At least 127 records · Page 7Linked to original sources
PubMed1993

Accurate measurement of surface areas of anatomical structures by computer-assisted triangulation of computed tomography images.

There is a need for accurate surface area measurement of internal irregular anatomical structures in order to define light dosimetry in adjunctive intraoperative photodynamic therapy (AIOPDT). No satisfactory preoperative method exists of measuring this parameter. We have investigated whether computer-assisted triangulation of serial sections generated by computed tomography (CT) scanning can give an accurate assessment of the surface area of the walls of the true pelvis after anterior resection and before colorectal anastomosis. We have shown that the technique of paper density tessellation is an acceptable method of measuring the surface areas of phantom objects, with a maximum error of 0.5%, and is used as the gold standard. Computer-assisted triangulation of CT images of standard geometric objects and accurately-constructed pelvic phantoms gives a surface area assessment with a maximum error of 2.5% compared with the gold standard. The CT images of 20 patients' pelves have been analysed by computer-assisted triangulation and this shows that the surface area of the walls varies from 143 cm2 to 392 cm2. Simple step-like analysis of images and approximation to geometric shapes with subsequent calculation give unacceptably high errors. The surface area of an internal, rigid, irregular surface area for illumination in AIOPDT can be accurately measured preoperatively by computer-assisted triangulation of CT images.

Anthropometry↗
PubMed1997

Psychology of computer use: XLVIII: Relation between playfulness and computer anxiety.

Correlations between scores for computer anxiety and for playfulness were investigated (N = 265). Scores on computer anxiety correlated negatively with overall scores on the playfulness scale and the factors, Fun and Creative. Only the correlation with scores on Creative remained significant when control for computer experience was imposed. The results imply that playfulness relates to computer anxiety indirectly through its relation with computer experience. The implications of the results for the validity of the Adult Playfulness Scale are briefly discussed.

Adolescent↗
PubMed2000

Computer automated design and computer automated manufacture.

The introduction of computer aided design and computer aided manufacturing into the field of prosthetics and orthotics did not arrive without concern. Many prosthetists feared that the computer would provide other allied health practitioners who had little or no experience in prosthetics the ability to fit and manage amputees. Technicians in the field felt their jobs may be jeopardized by automated fabrication techniques. This has not turned out to be the case. Prosthetists who use CAD-CAM techniques are finding they have more time for patient care and clinical assessment. CAD-CAM is another tool for them to provide better care for the patients/clients they serve. One of the factors that deterred the acceptance of CAD-CAM techniques in its early stages was that of cost. It took a significant investment in software and hardware for the prosthetists to begin to use the new systems. This new technique was not reimbursed by insurance coverage. Practitioners did not have enough information about this new technique to make a sound decision on their investment of time and money. Ironically, it is the need to hold health care costs down that may prove to be the catalyst for the increased use of CAD-CAM in the field. Providing orthoses and prostheses to patients who require them is a very labor intensive process. Practitioners are looking for better, faster, and more economical ways in which to provide their services under the pressure of managed care. CAD-CAM may be the answer. The author foresees shape sensing departments in hospitals where patients would be sent to be digitized, similar to someone going for radiograph or ultrasound. Afterwards, an orthosis or prosthesis could be provided from a central fabrication facility at a remote site, most likely on the same day. Not long ago, highly skilled practitioners with extensive technical ability would custom make almost every orthosis. One now practices in an atmosphere where off-the-shelf orthoses are the standard. This reduced fabrication time, but compromised the accuracy of the fit of a custom made orthosis. Computer aided design and manufacturing has the ability to combine the accuracy of custom made with the speed and labor savings of off-the-shelf systems. This would be a substantial benefit to patients, practitioners, and third party payors as well. The field may run full circle and return to custom made systems at off-the-shelf costs. As scientific knowledge base increases and computer aided design improves, one still needs the interface between the design methodology and the patient. That interface is the prosthetist/orthotist. The clinician and the clients they serve have a lot to gain from further research in this field. If one does not lose focus on how one can improve prostheses and orthoses for the consumer, one can expect great things from the methodology of CAD-CAM. There is no question that computerization is here and will continue to influence the fields of prosthetics and orthotics.

Artificial Limbs↗
PubMedDate not supplied

Development of a novel computer-aided diagnosis system for automatic discrimination of malignant from benign solitary pulmonary nodules on thin-section dynamic computed tomography.

OBJECTIVES: As an application of the computer-aided diagnosis of solitary pulmonary nodules (SPNs), 3-dimensional contrast-enhanced (CE) dynamic helical computed tomography (HCT) was performed to evaluate temporal changes in the internal structure of nodules to differentiate between benign nodules (BNs) and malignant nodules (MNs). METHODS: There were 62 SPNs (35 MNs and 27 BNs) included in this study. Scanning (2-mm collimation) was performed before and 2 and 4 minutes after CE dynamic HCT. The CT data were sent to a computer, and the pixels inside the nodule were characterized in terms of 3 parameters (attenuation, shape index, and curvedness value). RESULTS: Based on the CT data at 4 (MN: 1.81-27.1, BN: -42.8 to -3.29) minutes after CE-dynamic HCT, a score of 0 or higher can be assumed to indicate an MN. CONCLUSIONS: Three-dimensional computer-aided diagnosis of the internal structure of SPNs using CE dynamic HCT was found to be effective for differentiating between BNs and MNs.

Adult↗
PubMed2002

Real-time computing without stable states: a new framework for neural computation based on perturbations.

A key challenge for neural modeling is to explain how a continuous stream of multimodal input from a rapidly changing environment can be processed by stereotypical recurrent circuits of integrate-and-fire neurons in real time. We propose a new computational model for real-time computing on time-varying input that provides an alternative to paradigms based on Turing machines or attractor neural networks. It does not require a task-dependent construction of neural circuits. Instead, it is based on principles of high-dimensional dynamical systems in combination with statistical learning theory and can be implemented on generic evolved or found recurrent circuitry. It is shown that the inherent transient dynamics of the high-dimensional dynamical system formed by a sufficiently large and heterogeneous neural circuit may serve as universal analog fading memory. Readout neurons can learn to extract in real time from the current state of such recurrent neural circuit information about current and past inputs that may be needed for diverse tasks. Stable internal states are not required for giving a stable output, since transient internal states can be transformed by readout neurons into stable target outputs due to the high dimensionality of the dynamical system. Our approach is based on a rigorous computational model, the liquid state machine, that, unlike Turing machines, does not require sequential transitions between well-defined discrete internal states. It is supported, as the Turing machine is, by rigorous mathematical results that predict universal computational power under idealized conditions, but for the biologically more realistic scenario of real-time processing of time-varying inputs. Our approach provides new perspectives for the interpretation of neural coding, the design of experiments and data analysis in neurophysiology, and the solution of problems in robotics and neurotechnology.

Action Potentials↗
PubMed1990

A versatile dual axis programmable stepping motor controller for a personal computer: a specific application and tutorial for implementing a computer-controlled light microscope.

A simple programmable stepping motor circuit for controlling two independent stepping motors has been designed. The circuit is compatible with the IBM personal computer and needs only slight modification to work with virtually any other microcomputer. The motors can either be programmed by the host personal computer for remote operation, controlled directly by a joystick interface provided in the circuit, or a combination of the two procedures. Independent microprocessors control each stepping motor and can be easily programmed by the host computer via Input/Output ports designed into the circuit. A basic understanding of the circuit demonstrates some commonly used techniques for controlling microcomputer electronics through computer programming. The circuit will likely have many uses, although the implementation of a computerized microscope is explicitly described. The circuit is currently used in a neuroanatomical and neurochemical computer charting system at the University of Iowa.

Computer Peripherals↗
PubMedDate not supplied

Computed tomography colonography: feasibility of computer-aided polyp detection in a "first reader" paradigm.

OBJECTIVE: : To determine the feasibility of a computer-aided detection (CAD) algorithm as the "first reader" in computed tomography colonography (CTC). METHODS: : In phase 1 of a 2-part blind trial, we measured the performance of 3 radiologists reading 41 CTC studies without CAD. In phase 2, readers interpreted the same cases using a CAD list of 30 potential polyps. RESULTS: : Unassisted readers detected, on average, 63% of polyps > or =10 mm in diameter. Using CAD, the sensitivity was 74% (not statistically different). Per-patient analysis showed a trend toward increased sensitivity for polyps > or =10 mm in diameter, from 73% to 90% with CAD (not significant) without decreasing specificity. Computer-aided detection significantly decreased interobserver variability (P = 0.017). Average time to detection of the first polyp decreased significantly with CAD, whereas total reading case reading time was unchanged. CONCLUSION: : Computer-aided detection as a first reader in CTC was associated with similar per-polyp and per-patient detection sensitivity to unassisted reading. Computer-aided detection decreased interobserver variability and reduced the time required to detect the first polyp.

Adult↗
PubMed1982

Is it time for a computer in your practice? II. What tasks your computer can perform.

In this article, the potential benefits of an office computer system have been detailed. As computer costs and sizes decrease, and computing capabilities increase, even more benefits will be had in the future. Of course, not all of these benefits are applicable to all practices. Equally important to note are the many problems associated with installation and use of computer systems, and these must be taken into account before an intelligent decision can be made as to whether its acquisition would benefit your practice. Helping the physician to weigh the benefits of an office computer system against its costs and potential problems will be the subject of the next article in this series.

Computers↗
PubMed1994

Psychology of computer use: XXXI. Relating computer users' stress, daily hassles, somatic complaints, and anxiety.

The relation of computer users' stress, measured by the Computer Hassles Scale, and global stress, measured by the Daily Hassles Scale, with stress reactions, measured by the somatization-anxiety items of the SCL-90, was investigated in a college sample (N = 101). Computer hassles ratings were correlated .54 with daily hassles ratings and .57 with somatization-anxiety ratings. Daily hassles ratings were correlated .74 with somatization-anxiety ratings. These results provide important evidence on convergent validity for the Computer Hassles Scale as a measure of computer users' stress.

Adult↗
PubMed1983

Computer use and undergraduate education for computer use in Canadian health care foodservices.

Surveys were conducted to assess the computer use in 50 selected Canadian health care foodservice facilities and to determine the educational preparation for computer use in seven selected Canadian post-secondary education institutions which educate potential foodservice personnel. Both the foodservices and post-secondary educational institutions selected were represented at two workshops on computer-assisted foodservice management held in June 1980 and in May 1981. Only seven facilities used a computer for foodservice functions; nine foodservices planned to use a computer within the next two years. A list of applications in use, being planned and of future interest showed the priority areas for these foodservices. Only one post-secondary educational institution actually had an educational foodservice application for student use. The other six educational foodservice facilities covered the subject matter content by readings, lectures and discussions.

Canada↗
PubMed1994

Computed tomography after laminectomy for lumbar spinal stenosis. Patients' pain patterns, walking capacity, and subjective disability had no correlation with computed tomography findings.

OBJECTIVES: The purpose of this study was to evaluate the relationship between postoperative computed tomography findings and patients' pain patterns, walking capacity, and subjective disability after laminectomy for lumbar spinal stenosis. SUMMARY OF BACKGROUND DATA: Recent improvements in computed tomography have enabled this tool to reveal changes in a patient after an operation, but there is a paucity of comparative examinations regarding the lumbar spinal canal of asymptomatic and symptomatic patients after laminectomy for lumbar spinal stenosis. METHODS: Ninety-two patients (42 women, and 50 men) with a mean age of 55 years were operated upon. Mean follow-up time was 3.5 years. Based on computed tomography findings of the operative area, three patient groups were formed: 1) no stenosis, 2) moderate stenosis, 3) and severe stenosis. During treadmill testing, each patient's pain was evaluated by visual analogue scale. The patients were divided into four pain pattern groups: 1) pain in the back and leg, 2) pain in the back only, 3) pain in the leg only, and 4) no pain in the back and leg. Subjective disability was measured by the Oswestry disability score. RESULTS: The structural changes revealed by computed tomography, and the patients' pain patterns, walking capacity, and subjective disability did not correlate significantly with each other. CONCLUSIONS: Postoperative computed tomography has only limited value because asymptomatic and symptomatic patients yield similar findings after surgery for lumbar spinal stenosis.

Disability Evaluation↗
PubMed1997

Computer-assisted classification system for chest X-ray and computed tomography findings in occupational lung disease.

The ILO classification of pneumoconiotic changes in the lungs and pleura has become a standardized and widely accepted method of documentation in occupational medicine. Recently a classification system for computed tomography/high-resolution computed tomography (CT/HRCT) findings in the lung has been proposed as well. For both classification systems, computed-assisted programs have been developed that allow the storage and archiving of the results as well as further statistical processing. The programs are compatible with usual hardware configurations, have a comprehensible and transparent structure, and are easy to learn and adaptable to individual needs. The use of the computer-assisted classification systems is presented in the example of an insulator exposed to asbestos. The system of data documentation and processing has proved to be very practicable in the more than 2000 patients studied thus far.

Asbestosis↗
PubMed2006

Computer-assisted surgery and computer-assisted telesurgery in otorhinolaryngology.

Surgical preparation is enhanced by the availability of computer-generated three-dimensional models that allow surgeons to explore the surgical field in various projections prior to an actual operation. In fact, with adequate computed tomography images, an entire operation can be simulated beforehand so that surgeons can plan the safest and most effective approach and be prepared to avoid or overcome obstacles during the actual procedure. Also, computer technology allows surgeons to conduct remote consultations and to even perform telesurgery--that is, to operate on a patient from a great distance. In this article, we describe our experience with computer-assisted local and remote endoscopic sinus surgery in Croatia.

Computer Communication Networks↗
PubMed1992

Computer-assisted fusion of single-photon emission tomographic and computed tomographic images. Evaluation in complicated inflammatory disease.

Fusion of single-photon emission computed tomographic (SPECT) and x-ray computed tomographic (CT) images can facilitate the direct comparison of function and anatomy by simultaneously displaying comparable cross-sectional images. A computer-assisted fusion method was used to prospectively evaluate 10 patients with suspected inflammatory disease complicated by an associated condition. CT images were transferred to the nuclear computer. Image fusion was accomplished with standard scaling, rotation, translation, and stretching transformations, using anatomic or external landmarks. SPECT-CT fusion correctly localized the inflammatory process in all 10 cases and facilitated percutaneous drainage or preoperative surgical planning in 6.

Adolescent↗
PubMed1986

Computer corner #15. The AAOS: request for computer system proposal.

The Committee on Computer Science and Practice Management of the American Academy of Orthopaedic Surgeons has provided an excellent format to ensure a happy relationship between the vendor and the orthopaedic office using this package. Problems in communication and understanding between the vendor and the orthopaedic surgeon will undoubtedly be significantly reduced. How the system will work is the vendor's problem, but what you want it to do for you is your problem, and both of these issues are addressed in these questionnaires. It is recommended in the computer package that three vendor proposals be invited. Since the most frequent cause of computer problems is improper evaluation of what functions the computer system must perform in order to meet the needs of the orthopaedic office, this series of questionnaires is important. In addition to recommending this computer package, I would also emphasize that if at all possible--in spite of what may appear to be an excellent system on paper--try to visit an office in which the system has been in use over the past six to 12 months.

Humans↗
PubMed1998

Computed-tomography-based computer preoperative planning for total hip arthroplasty.

For precise preoperative planning in total hip arthroplasty (THA), we developed a technique of computed tomography (CT)-based computer preoperative planning and compared this technique with the single X-ray and template method generally used. The subjects of this study were 42 hips in 38 patients who underwent THA using a cementless total hip system. Preoperatively, a standard anteroposterior X-ray of the hip was taken, and conventional preoperative planning was done with a template of the total hip system. Transverse images were obtained using a helical CT scanner, and a CT-based computer preoperative plan was performed on true coronal slice images of the proximal femur reconstructed from CT data. Postoperatively, 29 hips (69%) showed good proximal fit of the femoral component to the medial endosteal line. Of the 20 hips with good proximal fit on preoperative X-ray planning, 12 hips had good proximal fit on postoperative X rays. Sensitivity and specificity of the proximal fit on X-ray templating were 41 and 23%, respectively. In 27 of 28 hips with good proximal fit on reconstructed CT images preoperatively, the postoperative X ray revealed good proximal fit. Sensitivity and specificity of the proximal fit on computer planning were 93 and 86%, respectively. Twelve hips with good proximal fit on preoperative templating, the reconstructed images, and the postoperative X ray had 20 degrees or less of combined femoral neck anteversion and external rotational contracture of the hip on the X-ray table. Eight hips with good proximal fit on preoperative templating and proximal poor fit on the reconstructed images had 17-65 degrees of combined version and rotational contracture. In 16 hips with poor proximal fit on preoperative templating and good proximal fit on the reconstructed images, the combined version and rotational contracture ranged from 17 to 69 degrees. When combined femoral neck anteversion and external rotational contracture of the hip is less than 15 degrees, the simple X-ray and template method might be sufficient for THA planning. Otherwise, the CT-based method of preoperative planning is recommended.

Arthroplasty, Replacement, Hip↗
PubMed1989

A unified computer program for assessment of attenuation correction and data acquisition methods in single photon emission computed tomography (SPECT).

A computer based simulation program was developed to assess the usefulness of various attenuation correction algorithms and data acquisition methods in single photon emission computed tomography (SPECT) in a unified approach. The program analytically calculated projection ray sums from a mathematical model with various distributions of activities and either uniform or non uniform attenuation coefficients by using the line integrals including the effect of attenuation. Data acquisition starting at arbitrary angles, various acquisition angles, including a 180 degree scan and a non circular orbit of a gamma camera, including an elliptical orbit can readily be taken into consideration in our simulation program. To simulate non circular orbit data acquisition, the resolution dependence on the object distance from the collimator surface was incorporated into the simulation. This computer based simulation program allows various combinations of attenuation correction algorithms such as hybrid methods, and data acquisition methods can be evaluated under a large number of study conditions. The usefulness of this computer based simulation program is shown with several representative examples.

Algorithms↗
PubMed2004

Computer-aided detection of kidney tumor on abdominal computed tomography scans.

PURPOSE: To implement a computer-aided detection system for kidney segmentation and kidney tumor detection on abdominal computed tomography (CT) scans. MATERIAL AND METHODS: Abdominal CT images were digitized with a film digitizer, and a gray-level threshold method was used to segment the kidney. Based on texture analysis performed on sample images of kidney tumors, a portion of the kidney tumor was selected as seed region for start point of the region-growing process. The average and standard deviations were used to detect the kidney tumor. Starting at the detected seed region, the region-growing method was used to segment the kidney tumor with intensity values used as an acceptance criterion for a homogeneous test. This test was performed to merge the neighboring region as kidney tumor boundary. These methods were applied on 156 transverse images of 12 cases of kidney tumors scanned using a G.E. Hispeed CT scanner and digitized with a Lumisys LS-40 film digitizer. RESULTS: The computer-aided detection system resulted in a kidney tumor detection sensitivity of 85% and no false-positive findings. CONCLUSION: This computer-aided detection scheme was useful for kidney tumor detection and gave the characteristics of detected kidney tumors.

Humans↗