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At least 235 records · Page 13Linked to original sources
PubMed1986

Red blood cell antibody identification and confirmation using commercial panels. A computer program for the IBM personal computer.

A menu-driven computer program that utilizes a data base of commercial panels was developed to assist in the identification and confirmation of red blood cell antibodies. A selected panel, along with the corresponding serum reactions, is displayed on the monitor and possible antibody patterns including dosage-dependent patterns are highlighted. A panel interpretation is then printed that includes a list of the possible (nonexcluded) antibodies, a probability level of identification for each possible antibody, and a table of antibody characteristics to aid in the differentiation among the possible antibodies. The panel data base can also be searched for additional red blood cells of specified phenotypes to confirm each suspected antibody. These additional red blood cells may be combined into a temporary panel for computer analysis. The program can also enter, print, edit, and delete any commercial panel from the data base. This computer program has proved to be faster and more accurate than the standard manual method for panel analysis, especially when multiple antibodies are present.

Antibodies↗
PubMed1984

A study of computer-assisted tomography. II. Comparison of metrizamide myelography and computed tomography in the diagnosis of herniated lumbar disc and spinal stenosis.

One hundred twenty-two patients with surgically confirmed pathology consisting of either herniated lumbar disc, spinal stenosis, or both were included in this investigation. For each of these patients, preoperative metrizamide myelography and computerized tomography were performed. Each myelogram and CT scan was read blindly so that the neuroradiologist interpreting the study had no knowledge of the patient's surgical pathology, clinical examination, nor any knowledge of the interpretation of the other preoperative test. A painstaking attempt was made to describe precisely both the exact nature of the preoperative myelogram and CT scan interpretations. The correlations between the preoperative interpretation of each test and the observed surgical findings then were analyzed statistically. Based upon this analysis, myelography was found to be more accurate than computed tomography in the diagnosis of herniated lumbar disc (83% vs. 72%). In the diagnosis of spinal stenosis, myelography was slightly more accurate than computed tomography (93% vs. 89%). Based upon the results of this study, the authors conclude that metrizamide myelography is more accurate than computed tomography in the diagnosis of both herniated lumbar disc and spinal stenosis and remains the diagnostic study of choice for these conditions. Furthermore, metrizamide myelography gives the added advantage of visualizing the thoracolumbar junction and, thus, affords the opportunity to diagnose occult spinal tumors.

False Negative Reactions↗
PubMed1977

[Continuous automatic ECG analysis using a computer with the cardiac signal directly led in from the patient (II). The diagnosis of heart rhythm disorders using a computer].

It is shown that appraisal and comparison of the duration of the R-R intervals in continuous surveillance of patients by means of electronic computers on the on-line regimen provides for automatic diagnosis of most types of disorders of the cardiac rhythm. The elaborated criterion of arrhythmic cardiac contraction (ACR-R), which takes into account not only the absolute value of the time between heart contractions but also the trend of the changes in the next R-R interval, provides a high percentage of revealed arrhythmic contractions. Disorders of the rate of cardiac contractions may be diagnosed by means of an electronic computer by comparison between the mean value of intervals of normal duration and the preset threshold values. Disorders of the rhythm may be diagnosed by means of an electronic computer by assessment and comparison of the arrangement of the combinations of short, normal, and long R-R intervals. The elaborated algorithms are described in detail and the block diagrams of the programs are shown.

Arrhythmia, Sinus↗
PubMed1995

[Computer system of the electronystagmographic examination. Part III. Comparative results obtained by computer and traditional technology in the examination of the vestibular organ].

The study presents a comparison of the research into results of vestibular organ stimulated with caloric tests which had been simultaneously registered with the help of a computer system of electronystagmographic examination, as well as the traditional electronystagmographic technic. In the case of 32 healthy persons there had been counted by hand average angular velocity of the slow phase caloric nystagmus average level of reduced excitability of labyrinth and direction predominance. It had been defined that those values are comparable to the ones given by the computer. That points to the right chose of the space of time in the climax of nystagmus reaction and a good identification of the phase both slow and fast by the computer system.

Adult↗
PubMedDate not supplied

[Personal computer-based computer monitoring system of the anesthesiologist (2-year experience in development and use)].

Creation of computer monitoring systems (CMS) for operating rooms is one of the most important spheres of personal computer employment in anesthesiology. The authors developed a PC RS/AT-based CMS and effectively used it for more than 2 years. This system permits comprehensive monitoring in cardiosurgical operations by real time processing the values of arterial and central venous pressure, pressure in the pulmonary artery, bioelectrical activity of the brain, and two temperature values. Use of this CMS helped appreciably improve patients' safety during surgery. The possibility to assess brain function by computer monitoring the EEF simultaneously with central hemodynamics and body temperature permit the anesthesiologist to objectively assess the depth of anesthesia and to diagnose cerebral hypoxia. Automated anesthesiological chart issued by the CMS after surgery reliably reflects the patient's status and the measures taken by the anesthesiologist.

Anesthesia↗
PubMed2006

Computed tomography angiography and computed tomography perfusion in ischemic stroke: A step-by-step approach to image acquisition and three-dimensional postprocessing.

Recent technical advances in both image acquisition and postprocessing have enabled computed tomography angiography (CTA) with computed tomography perfusion to become front-line tools for acute stroke evaluation in many institutions. This article provides a step-by-step approach to utilizing these technologies, particularly in the rapid triage of appropriate stroke patients to reperfusion therapies. The specific contrast injection, image acquisition, and 3D postprocessing protocols for high-quality CTA, currently in use at our institution, are delineated. An important point of emphasis is how preliminary angiographic and cerebral perfusion observations can be made immediately at the scanner to expedite emergent therapy. Also explored is the manner in which a dedicated 3D lab can support a high clinical volume, including a large percentage of emergent studies. An accurate yet time-efficient approach for the neuroradiologist to integrate 3D interpretation with CTA source data review is offered. Several important imaging and interpretive pitfalls in stroke CTA are illustrated.

Angiography↗
PubMedDate not supplied

Computer simulation of image intensifier-based computed tomography detector: vascular application.

This present study reports the results of a computer simulation whose aim was to predict the low-contrast imaging performance of which a conventional x-ray image intensifier with charge coupled device (CCD) camera would be capable if incorporated into a computed tomography (CT) volume imager. A vascular imaging task was modeled in our simulation. The effects of detector noise, x-ray exposure levels, analog-to-digital conversion (ADC) precision and residual levels of detected x-ray scatter were considered. The results of this simulation indicate that the low-contrast imaging performance of an image intensifier-based CT system was most limited by the CCD detector readout noise. Given this limitation the detection of greater than about 100,000 detected photons/pixel/projection gave marginal improvement in low-contrast resolution. At these exposures 12 bit ADC precision resulted in little additional image noise. The effects of detecting scattered x rays are twofold; decreasing the signal-to-noise ratio associated with our modeled artery and introducing a cupping artifact. Based on the results from the simulation, it appears that an image intensifier-based CT system is a feasible concept from a noise viewpoint, if the anticipated imaging task is intravenous angiography.

Angiography↗
PubMed2001

Efficacy of navigation in skull base surgery using composite computer graphics of magnetic resonance and computed tomography images.

The efficacy of a neurosurgical navigation system using three-dimensional composite computer graphics (CGs) of magnetic resonance (MR) and computed tomography (CT) images was evaluated in skull base surgery. Three-point transformation was used for integration of MR and CT images. MR and CT image data were obtained with three skin markers placed on the patient's scalp. Volume-rendering manipulations of the data produced three-dimensional CGs of the scalp, brain, and lesions from the MR images, and the scalp and skull from the CT. Composite CGs of the scalp, skull, brain, and lesion were created by registering the three markers on the three-dimensional rendered scalp images obtained from MR imaging and CT in the system. This system was used for 14 patients with skull base lesions. Three-point transformation using three-dimensional CGs was easily performed for multimodal registration. Simulation of surgical procedures on composite CGs aided in comprehension of the skull base anatomy and selection of the optimal approaches. Intraoperative navigation aided in determination of actual spatial position in the skull base and the optimal trajectory to the tumor during surgical procedures.

Computer Graphics↗
PubMed1991

Psychology of computer use: XXIV. Computer-related stress among technical college students.

Hudiburg's Computer Technology Hassles Scale, along with a measure of global stress and a scale on attitudes toward computers, were administered to 186 students in a two-year technical college. Hudiburg's work with the hassles scale as a measure of "technostress" was affirmed. Moderate, but statistically significant, correlations among the three scales are reported. No relationship between the hassles scale and achievement as measured by GPA was detected.

Achievement↗
PubMed1995

Computer-assisted dental implant surgery using computed tomography.

Standard planning for dental implants consists of a prosthesis simulation on diagnostic casts and radiographic examination of anatomical structures. The clinician visually locates the planned trajectory on the surgical site in the patient's mouth without direct correlation between the radiographs and the anatomy. We have developed a computer assisted technique to define the optimal position of the bone implant using computed tomography to accurately place the implant in the planned position using a guide drilled into a resin splint.

Computer Simulation↗
PubMed2001

Comparing 18-fluoro-2-deoxyglucose positron emission tomography with a combination of technetium 99m tetrofosmin single photon emission computed tomography and computed tomography to detect recurrent or persistent nasopharyngeal carcinomas after radiotherapy.

BACKGROUND: The diagnostic accuracy of combined computed tomography (CT) and technetium 99m tetrofosmin (Tc-TF) single photon emission computed tomography (SPECT) of head and neck to differentiate recurrent or residual nasopharyngeal carcinomas (NPCs) from benign lesions after radiotherapy was evaluated and compared with positron emission tomography (PET) with 18-fluoro-2-deoxyglucose (FDG). METHODS: Four months after radiotherapy, 36 patients with NPC underwent Tc-TF SPECT and CT of head and neck to differentiate recurrent or residual NPC from benign lesions. Histopathologic examinations were performed on nasopharyngeal biopsies of all 36 patients. RESULTS: Based on the biopsy results, the sensitivity, specificity, and accuracy of Tc-TF SPECT were 64%, 96%, and 86%, respectively, for differentiation of recurrent or persistent NPC from benign lesions. For CT and FDG-PET, the sensitivity, specificity, and accuracy were 73%, 88%, and 83% and 100%, 96%, 97%, respectively. For the 27 patients with NPC whose Tc-TF SPECT and CT results were congruent, the combination of Tc-TF SPECT and CT had the same sensitivity, specificity, and accuracy (100%, 96%, and 96%) as FDG-PET. For the nine patients with NPC with incongruent Tc-TF SPECT and CT results, FDG-PET correctly differentiated two benign lesions from seven recurrent/residual NPCs. CONCLUSIONS: Although, FDG-PET is the best tool for detecting recurrent or residual NPC, combined congruent Tc-TF SPECT and CT results achieved the same accuracy as FDG-PET. Therefore, we concluded that FDG-PET could be considered only when Tc-TF SPECT and CT give incongruent results.

Adolescent↗
PubMed1992

Computer-assisted 3D-reconstruction and statistics of the limbic system. 1. Computer-assisted 3D-reconstruction of the hippocampal formation, the fornix, and the mamillary bodies.

The hippocampal formation of eight perfusion-fixed human brains was examined using new methods according to stereotactic and morphometric principles (macrovibratome and computer-aided 3D reconstruction). The reconstructions form part of a neuroanatomical reference system (NeuRef). This reference system allows for 3D visualisation of the brain and its components on a computer graphic workstation, as well as for the presentation of the union set based on a neuroanatomical structure taken from this sample of brains. This retrievable knowledge of neurofunctional systems is important for the preoperative planning of neurosurgeons and the adjustment of radiotherapy.

Adult↗
PubMed2004

Value of image fusion using single photon emission computed tomography with integrated low dose computed tomography in comparison with a retrospective voxel-based method in neuroendocrine tumours.

The objective was the evaluation of single photon emission computed tomography (SPECT) with integrated low dose computed tomography (CT) in comparison with a retrospective fusion of SPECT and high-resolution CT and a side-by-side analysis for lesion localisation in patients with neuroendocrine tumours. Twenty-seven patients were examined by multidetector CT. Additionally, as part of somatostatin receptor scintigraphy (SRS), an integrated SPECT-CT was performed. SPECT and CT data were fused using software with a registration algorithm based on normalised mutual information. The reliability of the topographic assignment of lesions in SPECT-CT, retrospective fusion and side-by-side analysis was evaluated by two blinded readers. Two patients were not enrolled in the final analysis because of misregistrations in the retrospective fusion. Eighty-seven foci were included in the analysis. For the anatomical assignment of foci, SPECT-CT and retrospective fusion revealed overall accuracies of 91 and 94% (side-by-side analysis 86%). The correct identification of foci as lymph node manifestations (n=25) was more accurate by retrospective fusion (88%) than from SPECT-CT images (76%) or by side-by-side analysis (60%). Both modalities of image fusion appear to be well suited for the localisation of SRS foci and are superior to side-by-side analysis of non-fused images especially concerning lymph node manifestations.

Adult↗
PubMed2006

Computer-based anatomy a prerequisite for computer-assisted radiology and surgery.

RATIONALE AND OBJECTIVES: The aim of the study is to show the possibilities opened up by three-dimensional (3D) computer-based models of the human body for education in anatomy, training of radiological and endoscopic examinations, and simulation of surgical procedures. MATERIALS AND METHODS: Based on 3D data sets obtained from the Visible Human and/or clinical cases, virtual body models are created that provide an integrated spatial and symbolic description of the anatomy by using interactive color/intensity-based segmentation, ray casting visualization with subvoxel resolution, a semantic network for knowledge modeling, and augmented QuickTime VR (Apple Computer, Inc, Cupertino, CA) movies for presentation. RESULTS: From these models, various radiological, endoscopic, or haptic manifestations of the body can be derived. This is shown with examples from anatomy teaching, correlation of x-ray images with 3D anatomy for education in radiology, gastrointestinal endoscopy, correlation of ultrasound images with 3D anatomy in endoscopic ultrasonography, and simulation of drilling in temporal bone surgery. CONCLUSION: The presented models provide a means for realistic training in interpretation of radiological and endoscopic images of the human body. Furthermore, certain surgical procedures may be simulated realistically. Used as a complement to the current curriculum, these models have the potential to greatly decrease education times and costs.

Anatomy↗
PubMed2006

Pictorial review: electron beam computed tomography and multislice spiral computed tomography for cardiac imaging.

Electron beam computed tomography (EBCT) revolutionized cardiac imaging by combining a constant high temporal resolution with prospective ECG triggering. For years, EBCT was the primary technique for some non-invasive diagnostic cardiac procedures such as calcium scoring and non-invasive angiography of the coronary arteries. Multislice spiral computed tomography (MSCT) on the other hand significantly advanced cardiac imaging through high volume coverage, improved spatial resolution and retrospective ECG gating. This pictorial review will illustrate the basic differences between both modalities with special emphasis to their image quality. Several experimental and clinical examples demonstrate the strengths and limitations of both imaging modalities in an intraindividual comparison for a broad range of diagnostic applications such as coronary artery calcium scoring, coronary angiography including stent visualization as well as functional assessment of the cardiac ventricles and valves. In general, our examples indicate that EBCT suffers from a number of shortcomings such as limited spatial resolution and a low contrast-to-noise ratio. Thus, EBCT should now only be used in selected cases where a constant high temporal resolution is a crucial issue, such as dynamic (cine) imaging. Due to isotropic submillimeter spatial resolution and retrospective data selection MSCT seems to be the non-invasive method of choice for cardiac imaging in general, and for assessment of the coronary arteries in particular. However, technical developments are still needed to further improve the temporal resolution in MSCT and to reduce the substantial radiation exposure.

Animals↗
PubMed2004

Accuracy of facial soft tissue thickness measurements in personal computer-based multiplanar reconstructed computed tomographic images.

The purpose of this study was to determine the precision and accuracy of facial soft tissue measurement using personal computer (PC)-based multiplanar reconstructed (MPR) computed tomography (CT) images and to evaluate the effect of the various CT scanning protocols on the facial soft tissue thickness measurement. Thirteen different CT imaging protocols were used to image a cadaver head. MPR reformations and three-dimensional (3D) reconstructions viewed on a laptop PC were used to make measurements at six specific sites on each set of images. These measurements were compared to physical measurements at the same sites. Increasing the slice thickness resulted in decreased image quality. Within the same slice thickness, increasing the pitch ratio in the spiral mode, resulted in decreasing image quality. The image quality of conventional CT scanning was relatively poorer than that of the spiral CT scanning. However, the mean deviation from the physical measurement was within 0.43 mm in every instance. This mean deviation was quite small and clinically acceptable for measuring the soft tissue thickness of the facial area. PC-based MPR CT images of the face using routine scanning CT protocols can be used to accurately measure soft tissue thickness in the facial region. However, for more fine and accurate data collection, scanning protocols with slice thicknesses less than 5mm, and a spiral/helical mode pitch less than 2:1 are recommended.

Cadaver↗
PubMed2004

Model-based detection of lung nodules in computed tomography exams. Thoracic computer-aided diagnosis.

RATIONALE AND OBJECTIVES: In this study, we developed a prototype model-based computer aided detection (CAD) system designed to automatically detect both solid and subsolid pulmonary nodules in computed tomography (CT) images. By using this CAD algorithm, along with the radiologist's initial interpretation, we aim to improve the sensitivity of radiologic readings of CT lung exams. MATERIALS AND METHODS: We have developed a model-based CAD algorithm through the use of precise mathematic models that capture scanner physics and anatomic information. Our model-based CAD algorithm uses multiple segmentation algorithms to extract noteworthy structures in the lungs and a Bayesian statistical model selection framework to determine the probability of various anatomical events throughout the lung. We tested this algorithm on 50 low-dose CT lung cancer screening cases in which ground truth was produced through readings by three expert chest radiologists. RESULTS: Using this model-based CAD algorithm on 50 low-dose CT cases, we measured potential sensitivity improvements of 7% and 5% in two radiologists with respect to all noncalcified nodules, solid and subsolid, greater than 5 mm in diameter. The third radiologist did not miss any nodules in the ground truth set. The CAD algorithm produced 8.3 false positives per case. CONCLUSION: Our prototype CAD system demonstrates promising results as a tool to improve the quality of radiologic readings by increasing radiologist sensitivity. A significant advantage of this model-based approach is that it can be easily extended to support additional anatomic models as clinical understanding and scanning practices improve.

Algorithms↗