Search results for " Computer-Assisted"
showing 10 items of 1033 documents
Visual data mining with self-organising maps for ventricular fibrillation analysis
2012
Detection of ventricular fibrillation (VF) at an early stage is being deeply studied in order to lower the risk of sudden death and allows the specialist to have greater reaction time to give the patient a good recovering therapy. Some works are focusing on detecting VF based on numerical analysis of time-frequency distributions, but in general the methods used do not provide insight into the problem. However, this study proposes a new methodology in order to obtain information about this problem. This work uses a supervised self-organising map (SOM) to obtain visually information among four important groups of patients: VF (ventricular fibrillation), VT (ventricular tachycardia), HP (healt…
Introduction to coronary imaging with 64-slice computed tomography
2005
The aim of this article is to illustrate the main technical improvements in the last generation of 64-row CT scanners and the possible applications in coronary angiography. In particular, we describe the new physical components (X-ray tube-detectors system) and the general scan and reconstruction parameters. We then define the scan protocols for coronary angiography with the new generation of 64-row CT scanners to enable radiologists to perform a CT study on the basis of the diagnostic possibilities.
Acoustic methods for measuring the porosities of porous materials incorporating dead-end pores
2013
International audience; The acoustic properties of porous materials containing dead-end (DE) pores have been proposed by Dupont et al. [J. Appl. Phys. 110, 094903 (2011)]. In the theoretical description, two physical parameters were defined (the dead-end porosity and the average length of the dead-end pores). With the knowledge of the open porosity (measured with non-acoustic methods), and the measurement of kinematic porosity (also called the Biot porosity in this article), it is possible to deduce the dead-end porosity. Two acoustic methods for measuring the Biot porosity for a wide range of porosities are proposed. These methods are based on acoustic transmission and on the low and high …
Biologically inspired information processing and synchronization in ensembles of non-identical threshold-potential nanostructures.
2013
Nanotechnology produces basic structures that show a significant variability in their individual physical properties. This experimental fact may constitute a serious limitation for most applications requiring nominally identical building blocks. On the other hand, biological diversity is found in most natural systems. We show that reliable information processing can be achieved with heterogeneous groups of non-identical nanostructures by using some conceptual schemes characteristic of biological networks (diversity, frequency-based signal processing, rate and rank order coding, and synchronization). To this end, we simulate the integrated response of an ensemble of single-electron transisto…
[The effect of instrumentation on original apical foramen shape using steel vs niti rotatory: computerized analysis]
2002
BACKGROUND. A fundamental requirement to obtain a correct endodontic preparation depends on the respect, during cleaning and shaping, of the original morphology of the apical foramen, (AF), so that the filling material will form a complete seal. METHODS. In our previous studies, in order to verify if this presumption was respected using rotary NiTi instruments with cutting tip, we instrumented extracted teeth characterised by a different degree of root curvatures. Using a standardized system to replace the sample, the original shape of the apical foramen of each tooth was recorded using a computerised technique and then compared to the shape after instrumentation. The data showed difference…
Three-Dimensional Surface Display in Blood Pool Gated SPECT
1994
In 14 patients (4 in good health and 10 with coronary heart disease) a blood pool gated single photon emission computed tomography (SPECT) was executed. The transaxial slices of the cardiac blood pool were reconstructed. A three-dimensional surface display was employed for the analysis of the tomographic data. A fixed distance, a fixed threshold (50%), and some different planes of view were employed. The test permitted visualiza tion of the ventricular and the atrial movements in all patients. The right ventricle was clearly seen in the right anterior oblique plane of view. The aortic beating was seen. In normal patients the left ventricle, clearly seen in left anterior oblique plane, shra…
Pervasive access to MRI bias artifact suppression service on a grid.
2009
Bias artifact corrupts magnetic resonance images in such a way that the image is afflicted by illumination variations. Some of the authors proposed the Exponential Entropy Driven - Homomorphic Unsharp Masking (E2D-HUM) algorithm that corrects this artifact without any a priori hypothesis about the tissues or the Magnetic Resonance image modality. Moreover, E2D-HUM does not care about the body part under examination and does not require any particular training task. People who want to use this algorithm, which is Matlab-based, have to set their own computers in order to execute it. Furthermore, they have to be Matlab-skilled to exploit all the features of the algorithm. In our work we propos…
ERP denoising in multichannel EEG data using contrasts between signal and noise subspaces
2009
Abstract In this paper, a new method intended for ERP denoising in multichannel EEG data is discussed. The denoising is done by separating ERP/noise subspaces in multidimensional EEG data by a linear transformation and the following dimension reduction by ignoring noise components during inverse transformation. The separation matrix is found based on the assumption that ERP sources are deterministic for all repetitions of the same type of stimulus within the experiment, while the other noise sources do not obey the determinancy property. A detailed derivation of the technique is given together with the analysis of the results of its application to a real high-density EEG data set. The inter…
Color superposition: a new modality for contrast echocardiography.
1987
To improve the estimation of endocardial borders in echocardiography, a technique has been developed to combine images from contrasted and noncontrasted echocardiograms of the same heart-phase using a color superposition mode. This method allows both experienced as well as less experienced examiners to define the endocardial borders more reproducibly and objectively. This is achieved by displaying tissue structures as gray level images while the ventricular cavity is marked selectively by the color display of the contrast material zone. Results of volume estimations of the left ventricle by different examiners using several imaging modes including color superposition display are presented.
Can Applications Designed to Evaluate Visual Function Be Used in Different iPads?
2018
SIGNIFICANCE: Apple devices could be suitable for vision tests, provided that the test has been correctly adapted to the device, after considering the spatial and colorimetric characterization of the screen. PURPOSE: The majority of vision applications has not been developed by vision or colorimetry experts and suffers from conceptual and design errors that may lead average users to an erroneous assessment of their visual capabilities. The reliability of vision tests depends on the accurate generation of the necessary visual stimuli in a particular device. Our aim was to ascertain whether a given color test, designed for a colorimetrically characterized device, might be used in another simi…