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At least 1,225 records · Page 68Linked to original sources
PubMed1991

Flexibility and efficacy of automatic continuous fluorodeoxyuridine infusion in metastases from a renal cell carcinoma.

Complete and lasting control of diffuse metastases from a renal cell carcinoma has been achieved by automatic continuous infusion of a single cytotoxic agent, fluorodeoxyuridine (FUDR). A patient with a single brain metastasis from renal cell carcinoma developed pulmonary, mediastinal, and retroperitoneal metastases after radical nephrectomy. A Medtronic Synchromed pump (Medtronic Inc., Minneapolis, MN) was implanted for the circadian systemic infusion of FUDR in 14-day courses with 14-day drug-free intervals. A complete response (CR) at all sites, was obtained in 3 months, and maintained for 22 months. After a second brain metastasis, treated by radiation therapy and cisplatin as radiosensitizer, a CR was obtained again and is now of 31 months' duration, which is four times the record to date. The overall hospitalization was 2 days. Acceptance of the pump is excellent and it functions precisely and reliably. This case should stimulate greater interest in techniques of automatic continuous infusion of cytostatics, given its greater efficacy and lower toxicity.

Brain Neoplasms↗
PubMed2001

Automatic scan prescription for brain MRI.

Diagnostic brain MRI scans are usually performed by trained medical technologists who manually prescribe the position and orientation of a scanning volume. In this study, a fully automatic computer algorithm is described which compensates for variable patient positioning and acquires brain MRI scans in a predefined reference orientation. The method involves acquiring a rapid water-only pilot scan, segmenting the brain surface, and matching it to a reference surface. The inverse matching transformation is then used to adapt a geometric description of the desired scanning volume, defined relative to the reference surface, to the current patient. Both pilot scan and processing are performed within 30 sec. The method was tested in 25 subjects, and consistently recovered orientation differences between the reference and each subject to within +/-5 degrees. Compared to manual prescription, automatic scan prescription promises many potential benefits, including reduced scan times, reproducible scan orientations along anatomically preferable orientations, and better reproducibility for longitudinal studies. Magn Reson Med 45:486-494, 2001.

Algorithms↗
PubMed2002

Automatic amide I frequency selection for rapid quantification of protein secondary structure from Fourier transform infrared spectra of proteins.

Here we report the development of a new neural network based approach for rapid quantification of protein secondary structure from Fourier transform infrared (FTIR) spectra of proteins. A technique for efficiently reducing the amount of spectral data by almost 90% is suggested to facilitate faster neural network analysis. Additionally, an automatic procedure is introduced for selecting only those regions within the amide I band of protein FTIR spectra, which can be best related to secondary structure contents by subsequent neural network analysis. Based on a given reference set of FTIR spectra from proteins with known secondary structure, a subset of merely 29 out of 101 amide I absorbance values could be identified, which lead to an improved prediction accuracy. The average prediction accuracy achieved for helix, sheet, turn, bend, and other is 4.96% which is better than that achieved by alternative methods that have been previously reported indicating the significant potential of this approach. Our suggested automatic amide I frequency selection procedure may be easily extended to identify promising regions from spectral data recorded by other spectroscopic techniques, like for example circular dichroism spectroscopy.

Algorithms↗
PubMed1982

A Zipfian model of an automatic bibliographic system: an application to MEDLINE.

A Zipfian model of an automatic bibliographic system is developed using parameters describing the contents of it database and its inverted file. The underlying structure of the Zipf distribution is derived, with particular emphasis on its application to work frequencies, especially with regard to the inverted flies of an automatic bibliographic system. Andrew Booth developed a form of Zipf's law which estimates the number of words of a particular frequency for a given author and text. His formulation has been adopted as the basis of a model of term dispersion in an inverted file system. The model is also distinctive in its consideration of the proliferation of spelling errors in free text, and the inclusion of all searchable elements from the system's inverted file. This model is applied to the National Library of Medicine's MEDLINE. The model carries implications for the determination of database storage requirements, search response time, and search exhaustiveness.

MEDLARS↗
PubMed1985

Use of a personal computer with an automatic noninvasive ambulatory blood pressure monitoring device.

Automatic ambulatory blood pressure monitoring is a valid and reliable tool for intermittent noninvasive assessment of blood pressure over a 24-hour period. However, reporting devices to retrieve data from the recording device are dedicated to one task and are expensive. Because of this, we have developed computer programs for a popular inexpensive microcomputer that retrieves data from the Del Mar Pressurometer III, an R-wave gated automatic ambulatory blood pressure monitoring device. Furthermore, the derived data may be edited, computed to derive statistics, stored, retrieved, displayed, and reported in both numerical and graphical format. This same hardware is used for multiple other tasks.

Blood Pressure↗
PubMed1989

Ventricular reconstruction with vascular prosthesis after aneurysmectomy. Ability to defibrillate and utilize the automatic internal cardioverter defibrillator.

Adjunct surgical procedures for patients with malignant ventricular tachyarrhythmias who require the automatic internal cardioverter defibrillator include aortocoronary artery bypass graft surgery, valvular repair or replacement, subendocardial resection, and aneurysmectomy. Ventricular reconstruction and its compatibility with the AICD are described in a 64-year-old man who required treatment of refractory ventricular tachycardia as well as resection of a large anteroapical aneurysm. Reconstruction using a dacron patch preserved left ventricular geometry but did not adversely affect the ability to defibrillate and allowed successful utilization of the automatic defibrillator.

Cardiac Surgical Procedures↗
PubMed1990

Automatic junctional tachycardia in an adult.

We report an adult patient with junctional ectopic tachycardia, a condition which was initially described in infants, frequently in association with congenital defects. The patient had a rapid, irregular paroxysmal junctional tachycardia with a rate ranging from 160 to 220 beats/min, distinguishing it from the more common nonparoxysmal junctional tachycardia in which a slower heart rate is seen. The electrophysiological study performed during an episode of tachycardia demonstrated periods of atrioventricular dissociation and narrow QRS complexes as well as a junctional ectopic rhythm, which was suggested by a His deflection preceding each ventricular depolarization with a normal HV interval. Both the response to exercise and the results of atrial and ventricular stimulation suggested enhanced automaticity of a high junctional focus. Therapy combining procainamide, verapamil, and digitalis proved to be effective. Thus, junctional ectopic tachycardia can also occur in adults, probably due to enhancement of automaticity.

Adult↗
PubMed1980

Estimation of the performance of an array-processor oriented system for automatic Pap smear analysis.

The rapid progress in computer technology makes possible the automatic analysis of thousands of cells on a slide in the field of automatic uterine cancer cytology. Our approach starts with the high-resolution scanning of visually selected and classified single cells determining the training set for discriminant analysis. On the basis of more than 15 morphologic and textural features measured, correct classification results of 95% are reached. Our aim is to speed up our image processing system by means of an Array-Processor, the model AP 120 B from Floating Point Systems. In this study a realistic time estimation of the scanning, segmentation, feature extraction and classification of about 40,000 cells on a slide is performed.

Computers↗
PubMed1994

Automatic detection of clustered, fluorescent-stained nuclei by digital image-based cytometry.

Automatic image-based cytometry (IC) can conveniently quantify the distributions of several specific, fluorescence-labeled molecules within individual, isolated cells of slide- or tissue-based specimens. However, many specimens contain clusters of cells or nuclei that are not detected as individual entities by existing automatic methods. We have developed analysis algorithms which detected individual nuclei occurring in clusters or as isolated nuclei. Specimens were labeled with a fluorescent DNA stain, imaged and the images were segmented into regions of nuclei and background. Clusters of nuclei, identified by their size and shape, were divided into individual nuclei by searching for dividing paths between nuclei. The paths, which need not be straight, possessed the highest average gradient per pixel. In addition, both high- and low-pass filtered images of the original image were analyzed. For each individual nucleus, one of the three segmented regions representing the nucleus (from either the original or one of two filtered images) was chosen as the final result, based on the closeness of the regions to average nuclear morphology. The algorithms correctly detected a high proportion of isolated (328/333) and clustered (254/271) nuclei when applied to images of 2 microns prostate and breast cancer sections. Thus, these algorithms should enable much more accurate detection and analyses of nuclei in intact specimens.

Algorithms↗
PubMed1990

Image analysis techniques for automatic evaluation of two-dimensional electrophoresis.

Techniques for automatic analysis of two-dimensional electrophoresis gels by computer-aided image analysis are described. Original gels or photographic films are scanned using a laser scanner and the files are transferred to a microcomputer. The program package first performs a compression and preevaluation of the files. Spot identification and quantification is performed by the chain code algorithm after appropriate zooming and cutting. Labeling facilitates spot identification and quantification in numerical and graphical (pseudocolor) representation on peripheral devices for camera ready output. Interpolation between measured basepoints is performed by cubic spline algorithms which are automatically switched on and off, depending on the need by the program. High speed analysis and graphic representation is achieved using fast Assembler language routines rather than high level languages. One-dimensional gels can be analyzed using the same software. Spot matching between parallel two-dimensional gels has not yet been implemented.

Electrophoresis, Gel, Two-Dimensional↗
PubMed1991

The MELANIE project: from a biopsy to automatic protein map interpretation by computer.

The goals of the MELANIE project are to determine if disease-associated patterns can be detected in high resolution two-dimensional polyacrylamide gel electrophoresis (HR 2D-PAGE) images and if a diagnosis can be established automatically by computer. The ELSIE/MELANIE system is a set of computer programs which automatically detect, quantify, and compare protein spots shown on HR 2D-PAGE images. Classification programs help the physician to find disease-associated patterns from a given set of two-dimensional gel electrophoresis images and to form diagnostic rules. Prototype expert systems that use these rules to establish a diagnosis from new HR 2D-PAGE images have been developed. They successfully diagnosed cirrhosis of the liver and were able to distinguish a variety of cancer types from biopsies known to be cancerous.

Biopsy↗
PubMed2002

Automatic 3D registration for interventional MRI-guided treatment of prostate cancer.

The goal of this research is to register real-time interventional magnetic resonance imaging (iMRI) slice images with a previously obtained high-resolution MRI image volume, which in turn can be registered with functional images such as those from SPECT. The immediate application is in iMRI-guided treatment of prostate cancer, where additional images are desired to improve tumor targeting. In this article, simulation experiments are performed to demonstrate the feasibility of slice-to-volume registration for this application. We acquired 3D volume images from a 1.5-T MRI system and simulated low-field iMRI image slices by creating thick slices and adding noise. We created a slice-to-volume mutual information registration algorithm with special features to improve robustness. Features included a multiresolution approach, two similarity measures, and automatic restarting to avoid local minima. To assess the quality of registration, we calculated 3D displacements on a voxel-by-voxel basis over a volume of interest between slice-to-volume registration and volume-to-volume registration, which was previously shown to be quite accurate. More than 800 registration experiments were performed on MR images of three volunteers. The slice-to-volume registration algorithm was very robust and accurate for transverse slice images covering the prostate, with a registration error of only 0.4 +/- 0.2 mm. Error was greater at other slice orientations and positions. The automatic slice-to-volume mutual information registration algorithm is robust and probably sufficiently accurate to aid in iMRI-guided treatment of prostate cancer.

Algorithms↗
PubMedDate not supplied

Effects of terbutaline on cardiac automaticity and contractility.

The effects of terbutaline, a sympathomimetic amine with predominantly beta 2-agonist properties, on cardiac automaticity and contractility were studied. For isolated rabbit right atria, terbutaline, 1 X 10(-9) to 1 X 10(-5)M, was significantly less potent than isoproterenol. The maximum increase in heart rate induced by terbutaline was 45 +/- 17 beats/min, that by isoproterenol, 120 +/- 9 beats/min. For canine Purkinje fibers, terbutaline had less effect on spontaneous rate than isoproterenol; maximum increases above control were 9.5 +/- 2.5 and 18.6 +/- 7.0 beats/min, respectively. For isolated feline ventricular muscle, terbutaline, 1 X 10(-9) to 1 X 10(-6)M, was significantly less potent than isoproterenol in increasing peak developed tension and the rate of tension development. Superfusion with Tyrode's solution containing terbutaline, 1 X 10(-7)M, plus graded concentrations of isoproterenol, 1 X 10(-9) to 1 X 10(-6)M, resulted in response which were less than those observed when isoproterenol alone was superfused. Maximal effects of isoproterenol plus terbutaline were equivalent to those of isoproterenol in its effect on cardiac contractility and automaticity and explain the clinical observation that terbutaline is less toxic than isoproterenol in its effects on cardiac rhythm and contraction when administered for the treatment of bronchial asthma.

Animals↗
PubMed2003

Automatic analysis of normal bone marrow blood cells using the XE-2100 automated hematology analyzer.

The bone marrow aspiration test conventionally has been performed by visual methods, using a light microscope, because automatic blood cell analyzers cannot adequately capture erythroblasts and immature granulocytes (IGs) (Tatsumi et al.: Osaka City Med J 1988;34:135-146; Tatsumi et al.: Am J Clin Pathol 1986;86:50-54). With the development of the XE-2100 automatic blood cell analyzer (Sysmex Corporation, Kobe, Japan) in 1999, the classification of erythroblasts and IGs by means of flow cytometry (Zini et al.: Infus Ther Transfus Med 2001;28:277-279; Briggs et al.: Sysmex J Int 1999;9:113-119) became possible. In the present study we classified cells in 65 bone marrow aspiration specimens by the microscopic method and with the XE2100, and compared the results. A good correlation was found in the nucleated red blood cell (NRBC), white blood cell (WBC), and total nucleated cell (TNC) counts; the myeloid/erythroid ratio (M/E ratio); neutrophils, lymphocytes, eosinophils, and IGs in the immature myeloid information (IMI) channel; and the total cell count. These items can all be analyzed in about 54 sec with the XE2100, which is faster than with the microscopic method. Therefore, analysis of bone marrow aspiration specimens with this apparatus appears to be very useful for clinical screening as well as laboratory testing.

Biopsy, Needle↗
PubMed2004

Automatic segmentation of diatom images for classification.

A general framework for automatic segmentation of diatom images is presented. This segmentation is a critical first step in contour-based methods for automatic identification of diatoms by computerized image analysis. We review existing results, adapt popular segmentation methods to this difficult problem, and finally develop a method that substantially improves existing results. This method is based on the watershed segmentation from mathematical morphology, and belongs to the class of hybrid segmentation techniques. The novelty of the method is the use of connected operators for the computation and selection of markers, a critical ingredient in the watershed method to avoid over-segmentation. All methods considered were used to extract binary contours from a large database of diatom images, and the quality of the contours was evaluated both visually and based on identification performance.

Algorithms↗
PubMed2003

Improvement in the quantification of myocardial perfusion using an automatic spline-based registration algorithm.

PURPOSE: To improve the quantification of myocardial perfusion by registering the time series of magnetic resonance (MR) images with injection of gadolinium. MATERIALS AND METHODS: Eight patients underwent MR scans to perform myocardial perfusion exam. Two short axis views of the left ventricle (LV) were acquired in free breathing. Two masks for performing the spatial registration of the images were evaluated. The registration was based on pixel intensity in a multi-resolution scheme. The efficiency of this correction was evaluated by calculating geometric residual displacement of the LV and by fitting the data to a compartment model fit with two parameters: K1, the blood-to-myocardium transfer coefficient, and Vd, the distribution volume of the contrast media. RESULTS: The registration stage allowed a decrease in the observed motion of the LV from more than 1.98 +/- 0.68 mm to less than 0.56 +/- 0.18 mm (mean +/- SD). Variability obtained in the perfusion analysis decreased from 46 +/- 103% to 5+/- 4% for K1 parameter and from 18 +/- 21% to 5 +/- 5% for Vd parameter. CONCLUSION: As with manual correction, this automatic motion correction leads to accurate perfusion parameters in dynamic cardiac MR imaging after contrast agent injection. This automatic stage requires placing only one mask over one frame of the perfusion study instead of manually shifting each image to fit a reference image of the perfusion study.

Algorithms↗
PubMed2004

Automatic model-based evaluation of magnetic resonance-guided radio frequency ablation lesions with histological correlation.

PURPOSE: To develop a model-based method for automatic evaluation of radio frequency (RF) ablation treatment using magnetic resonance (MR) images. MATERIALS AND METHODS: RF current lesions were generated in a rabbit thigh model using MR imaging (MRI) guidance. We created a 12-parameter, three-dimensional, globally deformable model with quadric surfaces that delineates lesion boundaries and is automatically fitted to MR grayscale data. We applied this method to in vivo T2- and contrast-enhanced (CE) T1-weighted MR images acquired immediately post-ablation and four days later. We then compared results to manually segmented MR and three-dimensional registered corresponding histological boundaries of cellular damage. RESULTS: Resulting lesions featured a two-boundary appearance with an inner region and an outer hyperintense margin on MR images. For automated vs. manual MR boundaries, the mean errors over all specimens were 0.19 +/- 0.51 mm and 0.27 +/- 0.52 mm for the inner surface, and -0.29 +/- 0.40 mm and -0.12 +/- 0.17 mm for the outer surface, for T2- and CE T1-weighted images, respectively. For automated vs. histological boundaries, mean errors over all specimens were 0.07 +/- 0.64 mm and 0.33 +/- 0.71 mm for the inner surface, and -0.27 +/- 0.69 mm and 0.02 +/- 0.43 mm for the outer surface, for T2- and CE T1-weighted images, respectively. All boundary errors compared favorably to MR voxel dimensions, which were 0.7 mm in-plane and 3.0 mm thick. CONCLUSION: The method is accurate both in describing MR-apparent boundaries and in predicting histological response and has applications in lesion visualization, volume estimation, and treatment evaluation.

Algorithms↗
PubMed2004

Automatic registration of brain magnetic resonance images based on Talairach reference system.

PURPOSE: To demonstrate a robust registration method of brain magnetic resonance (MR) images based on the Talairach reference system with automatic determinations of the fiducial points. MATERIALS AND METHODS: Eight specified landmark points of the Talairach reference system are determined after successfully extracting the midsagittal plane from three-dimensional MR imaging (MRI) data. Projection information of the image intensity is used to determine the midline of the cerebrum in axial and coronal view images, which is a necessary step for extraction of the midsagittal plane. To find the landmarks of anterior commissure (AC) and posterior commissure (PC) in the midsagittal plane, we adopt two-step shape matching that properly finds locations of the corpus callosum (CC), and then AC and PC, respectively. The shape matching is performed on the edge-enhanced midsagittal plane image to minimize dependency on image intensity variation. Other landmark points of the Talairach reference system are determined by fitting the intensity curve of the cutview with the Gaussian model. RESULTS: The proposed method automatically determines seven landmark points, except the inferior point (IP), and the brain MR images can be successfully registered with the Talairach reference system. CONCLUSION: The suggested registration method can be applied to any MR images for functional studies. It can also be applied to patients unless their brains are highly deformed or have a highly deformed CC.

Brain↗