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At least 145 records · Page 8Linked to original sources
PubMed1996

Three-dimensional computed imaging using a personal computer for nasal surgery.

Three-dimensional (3-D) computed imaging was applied before surgery in 16 patients with nasal or paranasal disease. The images obtained by computed tomography (CT) were scanned by a personal computer. The contours of the organs were outlined on the scanned images, and the images were then reconstructed using 3-D imaging software. The resulting 3-D images were evaluated and compared with actual surgical images. The 3-D images were found to be useful for surgical procedures, because they facilitated recognition of the topologic relation between structure and lesion. Although this method requires a personal computer and an image scanner, it is cheaper than, and in some respects even superior to, a 3-D CT system.

Adult↗
PubMed1997

Accuracy of computer-assisted pedicle screw placement. An in vivo computed tomography analysis.

STUDY DESIGN: A computer-assisted planning and visualization system (the Orthopaedic Surgery Planning System) was tested for pedicle screw insertion in vivo. OBJECTIVES: To evaluate the system's applicability for regular intraoperative use and its accuracy for pedicle screw placement in vivo. SUMMARY OF BACKGROUND DATA: Pedicle screw placement poses considerable anatomic and biomechanical risks. The reported rates of screw misplacement with conventional insertion techniques are unacceptably high. It previously has been shown in vitro that computer assistance offers the potential to decrease the number of screws perforating the pedicular cortex. METHODS: The accuracy of 162 pedicle screws inserted with the Orthopaedic Surgery Planning System was assessed by means of postoperative computed tomography evaluation. Reconstructions of the horizontal, frontal, and sagittal planes were analyzed. Cortex perforations were graded in steps of 2 mm. RESULTS: The cortex was perforated in 2.7% of pedicles. Complete preoperative computed tomography scanning of the levels to be operated on is essential to allow for a precise image reconstruction. Initial difficulties in applying the system contribute to the malplacements. A learning curve for general handling of the Orthopaedic Surgery Planning System was observed. CONCLUSIONS: The system provides a safe and reproducible technique for pedicle screw insertion. Other applications in the field of spine surgery are under evaluation.

Bone Screws↗
PubMed2006

Two-year outcomes of computed tomography-based and computed tomography free navigation for total knee arthroplasties.

UNLABELLED: Optimal component position in all planes and well-balanced soft tissues facilitate a good clinical outcome and long-term survival after total knee arthroplasties. We investigated the accuracy of implantation of navigated total knee arthroplasties at 3 months followup and the influence on the clinical outcome at 2 years followup. Forty-four patients (44 procedures) were enrolled in our prospective study. One half of the surgeries were performed using a computed tomography-based navigation system, and half were performed with imageless navigation. Outcomes were based on the Insall knee score parameters, anterior knee pain, patient satisfaction, feeling of instability, and step test. The radiographic parameters were the mechanical axis, tibial slope, lateral distal femoral angle, and medial proximal tibial angle. The radiographic measurements were similar in both groups (patients within +/- 3 degrees inaccuracy range in computed tomography-based/imageless groups; mechanical axis 86%/81%, tibial slope 95%/91%, lateral distal femoral angle 95%/91%, medial proximal tibial angle 91%/95%). The imageless system provided equal radiographic results, but we found improved ligament balancing in the computed tomography free group. The computed tomography-based approach has a good pre-operative planning procedure, but is more expensive and time consuming. LEVEL OF EVIDENCE: Therapeutic Study, Level II. See the Guidelines for Authors for a complete description of levels of evidence.

Aged↗
PubMed2006

Enabling computer models of the heart for high-performance computers and the grid.

Although it is now feasible to compute multi-cellular models of the heart on a personal desktop or laptop computer, it is not feasible to undertake the detailed sweeps of high-dimensional parameter spaces required if we are to undertake in silico experimentation of the complex processes that constitute heart disease. For this research, modelling requirements move rapidly beyond the limit of commodity computers' resource both in terms of their memory footprint and the speed of calculation, so that multi-processor architectures must be considered. In addition, as such models have become more mature and have been validated against experimental data, there is increasing pressure for experimentalists to be able to make use of these models themselves as a key tool for hypothesis formulation and in planning future experimental studies to test those hypotheses. This paper discusses our initial experiences in a large-scale project (the Integrative Biology (IB) e-Science project) aimed at meeting these dual aims. We begin by putting the research in context by describing in outline the overall aims of the IB project, in particular focusing on the challenge of enabling novice users to make full use of high-performance resources without the need to gain detailed technical expertise in computing. We then discuss our experience of adapting one particular heart modelling package, Cellular Open Resource, and show how the solving engine of this code was dissected from the rest of the package, ported to C++ and parallelized using the Message-Passing Interface. We show that good parallel efficiency and realistic memory reduction can be achieved on simple geometries. We conclude by discussing lessons learnt in this process.

Action Potentials↗
PubMed2004

Efficient migration of complex off-line computer vision software to real-time system implementation on generic computer hardware.

This paper addresses the problem of migrating large and complex computer vision code bases that have been developed off-line, into efficient real-time implementations avoiding the need for rewriting the software, and the associated costs. Creative linking strategies based on Linux loadable kernel modules are presented to create a simultaneous realization of real-time and off-line frame rate computer vision systems from a single code base. In this approach, systemic predictability is achieved by inserting time-critical components of a user-level executable directly into the kernel as a virtual device driver. This effectively emulates a single process space model that is nonpreemptable, nonpageable, and that has direct access to a powerful set of system-level services. This overall approach is shown to provide the basis for building a predictable frame-rate vision system using commercial off-the-shelf hardware and a standard uniprocessor Linux operating system. Experiments on a frame-rate vision system designed for computer-assisted laser retinal surgery show that this method reduces the variance of observed per-frame central processing unit cycle counts by two orders of magnitude. The conclusion is that when predictable application algorithms are used, it is possible to efficiently migrate to a predictable frame-rate computer vision system.

Algorithms↗
PubMed1989

New trends in computer graphics and computer vision to assist functional neurosurgery.

Computer vision (CV), a computerized method to analyze digital images (e.g., CT scans), and computer graphics (CG), a set of computer programs for displaying two, three- or four-dimensional data, are recent computer techniques which are appropriate to assist functional stereotactic surgery. CV and CG are useful for the evaluation of spatial relations between anatomical structures and the sites of spontaneous neuronal noise or of electrophysiological stimulation data gathered during stereotactic interventions for movement disorders. CV and CG can be employed for stereotactic operation planning, during the operation for target point evaluation and for further postoperative data analysis.

Computer Graphics↗
PubMedDate not supplied

Description of the computer-based patient record and computer-based patient record system. CPRI Work Group on CPR Description.

Computer-based patient records and computer-based patient record systems support health care effectiveness and efficiency with appropriate safeguards for confidentiality. Achieving a health information infrastructure with computer-based patient records supported by fully integrated computer-based patient record systems is obviously a process of incremental steps. However, CPRI believes significant benefits in health care delivery are certain to be realized over the full course of this process.

Computer Communication Networks↗
PubMed1980

An evaluation of the use of mini-computers for computer assisted instruction in allied health curricula.

This paper reports the results of an evaluation of computer assisted instruction in a school of allied health technologies. This evaluation was conducted to determine how students rated computer assisted instruction as a learning tool. Areas rated were: (1) ease of use of computer hardware, (2) ease of use of computer instructions, (3) difficulty of content and (4) learning value. The results of 1,507 student questionnaires were tabulated. Student evaluation was favorable in all areas. Comments by the students have led to revisions in specific programs.

Computer-Assisted Instruction↗
PubMed1980

[Computer-assisted irradiation planning by means of computed tomography (author's transl)].

Operation of the computer tomograph combined with a computer for irradiation planning leads to an optimization of radiotherapeutic efforts. By means of a careful carrying-over of computed tomographic data into the computing system the demanded homogeneous dose distribution with a deviation rate of +/- 10% may be accomplished to a large extent for any given target volume. At the same time this method achieves an optimal sparing of the sound or else critical organs. An evaluation unit independent of the diagnostics ought to be available, as this renders possible the adaptation of the CT cross-sections of interest under individual aspects.

Computers↗
PubMed1990

Computer aided stress analysis of long bones utilizing computed tomography.

A computer aided analysis method has been developed which utilizes computed tomography (CT) and a finite element (FE) computer program to determine the stress-displacement pattern in a long bone section. The CT data file provides the geometry, the apparent density and the elastic properties for the three-dimensional FE model. A developed pre-processor generates the FE model of a human diaphyseal tibia section which is then analyzed by the SAP IV finite element program. The results obtained are sorted and displayed by a developed post-processor and compared with stresses and deformations from the literature. The model generation method was verified by applying it to a model of simple geometry and boundary conditions, then comparing the results with the analytical solution of the same problem. The convergence behavior of nodal displacements was tested as a function of mesh refinement. This method provides an automatic, versatile, non-invasive and accurate tool of long bone modeling for finite element stress analysis.

Algorithms↗
PubMed2001

Computer-guided surgery utilizing a computer-milled surgical template.

The primary objective of implant placement is to support prosthetic restorations that return patients to proper oral form, function, and aesthetics. Since correct implant placement can be a technique-sensitive process, it is performed in conjunction with various diagnostic and guidance procedures. For accurate diagnosis, radiographic templates, computed tomography scans, and surgical simulation software are unparalleled. This article demonstrates the manner by which computer-guided surgery and computer-milled surgical templates can enable precise implant placement for the entire implant team.

Alveolar Process↗
PubMed2006

Structural model of the mAb 806-EGFR complex using computational docking followed by computational and experimental mutagenesis.

In this work, we combined computational protein-protein docking with computational and experimental mutagenesis to predict the structure of the complex formed by monoclonal antibody 806 (mAb 806) and the epidermal growth factor receptor (EGFR). We docked mAb 806, an antitumor antibody, to its epitope of EGFR residues 287-302. Potential mAb 806-EGFR orientations were generated, and computational mutagenesis was used to filter them according to their agreement with experimental mutagenesis data. Further computational mutagenesis suggested additional mutations, which were tested to arrive at a final structure that was most consistent with experimental mutagenesis data. We propose that this is the EGFR-mAb 806 structure, in which mAb 806 binds to an untethered form of the receptor, consistent with published experimental results. The steric hindrance created by the antibody near the EGFR dimer interface interferes with receptor dimerization, and we postulate this as the structural origin for the antitumor effect of mAb 806.

Antibodies, Monoclonal↗
PubMed2002

Personal computer-based PACS display system: comparison with a dedicated PACS workstation for review of computed radiographic images in rheumatoid arthritis.

RATIONALE AND OBJECTIVES: The authors' purpose was to investigate the reliability of a personal computer (PC)-based display system compared with a workstation in the evaluation of rheumatoid arthritis on computed radiographs of the hands. MATERIALS AND METHODS: Two radiologists on two occasions independently scored randomized computed radiographs of individual joints of the hands from 23 patients with rheumatoid arthritis and 14 control subjects. Each joint was scored from 0 (definitely normal) to 30 (severe disease) for each of four variables: soft-tissue swelling, osteopenia, erosions, and joint space narrowing. The observations were replicated on a picture archiving and communication system workstation and a PC. Intraobserver and interobserver reliability were calculated, as was the difference in scores between the two systems. The null hypothesis was that there was no difference between the workstation and the PC. RESULTS: The intraobserver reliability for normal versus abnormal joints was 73% with the workstation and 79% with the PC. The intraobserver reliability for workstation versus PC was 83%. There was moderate interreader reliability for both platforms (average kappa statistic, 0.46 [workstation] vs 0.45 [PC]). Small differences in scores between platforms are probably due mostly to the ordinal nature of the scoring system. CONCLUSION: For evaluating computed radiographs of the hands in early rheumatoid arthritis, a PC-based system provides results similar to those obtained with a workstation, at considerably reduced cost.

Arthritis, Rheumatoid↗
PubMed1976

Computer-assisted differential diagnosis of laboratory abnormalities and follow-up testing. Evaluation of the accuracy of a computer program.

An evaluation is made of a computer program which generates a differential diagnostic list given a set of input data obtained from an admission chemistry screening profile. The program is tested by supplying input data on patients for whom diseases are known. The laboratory data from 367 patients are examined. Accurate computer diagnosis is obtained in many disease categories. The original computer program is modified to suggest the follow-up tests indicated based on the diagnoses it makes. By using this program and some additional clinical input from the physician, the clinical pathologist can select the most appropriate computer diagnosis and begin the follow-up testing. Accelerated diagnosis and patient care should result.

Aged↗
PubMed2002

The computational challenges of applying comparative-based computational methods to whole genomes.

The explosion in genomic sequence available in public databases has resulted in an unprecedented opportunity for computational whole genome analyses. A number of promising comparative-based approaches have been developed for gene finding, regulatory element discovery and other purposes, and it is clear that these tools will play a fundamental role in analysing the enormous amount of new data that is currently being generated. The synthesis of computationally intensive comparative computational approaches with the requirement for whole genome analysis represents both an unprecedented challenge and opportunity for computational scientists. We focus on a few of these challenges, using by way of example the problems of alignment, gene finding and regulatory element discovery, and discuss the issues that have arisen in attempts to solve these problems in the context of whole genome analysis pipelines.

Computational Biology↗
PubMed1994

A method for automatic edge detection and volume computation of the left ventricle from ultrafast computed tomographic images.

RATIONALE AND OBJECTIVES: Detection of endocardial and epicardial borders of the left ventricle (LV) using various imaging modalities is time-consuming and prone to interpretive error. An automatic border detection algorithm is presented that is used with ultrafast computed tomographic images of the heart to compute cavity volumes. METHODS: The basal-level slice is identified, and the algorithm automatically detects the endocardial and epicardial borders of images from the basal to the apical levels. From these, the ventricular areas and chamber volumes are computed. The algorithm uses the Fuzzy Hough Transform, region-growing schemes, and optimal border-detection techniques. The cross-sectional areas and the chamber volumes computed with this technique were compared with those from manually traced images using canine hearts in vitro (n = 8) and studies in clinical patients (n = 27). RESULTS: Though the correlation was good (r = .88), the algorithm overestimated the LV epicardial area by 4.8 +/- 6.4 cm2, though this error was not statistically different from zero (P > .05). There was no difference in endocardial areas (r = .95, P > .05). The algorithm tended to underestimate the end-diastolic volume (r = .94) and the end-systolic volume (r = .94), although these errors were not statistically different from zero (P > .05). The algorithm tended to underestimate the ejection fraction (r = .80), although this error was not statistically different from zero (P > .05). CONCLUSIONS: Automatic detection of myocardial borders provides the clinician with a useful tool for calculating chamber volumes and ejection fractions. The algorithm, with the corrections suggested, provides an accurate estimation of areas and volumes. This algorithm may be useful for contour border identification with ultrasound, positron-emission tomography, magnetic resonance imaging, and other imaging modalities in the heart, as well as other structures.

Algorithms↗
PubMedDate not supplied

Fractional quantitative computed tomography for bone mineral density evaluation: accuracy, precision, and comparison to quantitative computed tomography.

OBJECTIVE: To evaluate bone mineral density considering its distribution, fractional quantitative computed tomography (fQCT) was designed and verified. METHODS: Quantitative computed tomography (QCT) was performed at 64 areas in 10 swine long bones. Fractional quantitative computed tomography was measured at the identical areas as the proportion of pixels showing a bone density higher than 130 mg/mL equivalent. All target areas were extracted and incinerated to measure apparent ash bone density. Based on standard references, the accuracy and precision of fQCT were evaluated and the results were compared with conventional QCT results. RESULTS: The correlation coefficient between fQCT and apparent ash bone density was 0.843 (P < 0.0001). The fQCT showed good correlation with volume fraction (r = 0.88, P < 0.0001). The coefficient of variation of fQCT was 0.42%. The fQCT revealed higher accuracy and precision than the results of QCT. CONCLUSION: Fractional quantitative computed tomography was designed and verified as a reliable method to measure bone mineral density.

Animals↗
PubMed1998

Computers in medical education 2. Use of a computer package to supplement the clinical experience in a surgical clerkship: an objective evaluation.

BACKGROUND: Student teaching of surgery has been devolved from the university in an effort to increase and broaden undergraduate clinical experience. In order to ensure uniformity of learning we have defined learning objectives and provided a computer-based package to supplement clinical teaching. A study was undertaken to evaluate the place of computer-based learning in a clinical environment. METHODS: Twelve modules were provided for study during a 6-week attachment. These covered clinical problems related to cardiology, neurosurgery and gastrointestinal haemorrhage. Eighty-four fourth-year students undertook a pre- and post-test assessment on these three topics as well as acute abdominal pain. No extra learning material on the latter topic was provided during the attachment. RESULTS: While all students showed significant improvement in performance in the post-test assessment, those who had access to the computer material performed significantly better than did the controls. Within the topics, students in both groups performed equally well on the post-test assessment of acute abdominal pain but the control group's performance was significantly lacking on the topic of gastrointestinal haemorrhage, suggesting that the bulk of learning on this subject came from the computer material and little from the clinical attachment. CONCLUSIONS: This type of learning resource can be used to supplement the student's clinical experience and at the same time monitor what they learn during clinical clerkships and identify areas of weakness.

Clinical Clerkship↗