Search results for "Algorithms"
showing 10 items of 1716 documents
Two-dimensional echocardiographic evaluation of left ventricular ejection fraction by the ellipsoid single-plane algorithm: a reliable method for ass…
1995
The reliability of two-dimensional (2D) echocardiographic estimation of left ventricular ejection fraction (EF) is commonly recognized, but no satisfactory data are available about the accuracy of low or very low EF values determined by 2D echocardiography (ECHO-EF). The purpose of our study was to assess the reliability of low ECHO-EF values obtained using a simple time-economical algorithm such as the ellipsoid single-plane area-length method. Radionuclide angiography (RAD-EF) was taken as the standard of comparison. We studied 59 consecutive patients (31 women and 28 men) referred to our echocardiographic laboratory. Both 2D echocardiography and radionuclide angiography were blindly perf…
Territorial belonging of the middle hepatic vein in living liver donor candidates evaluated by three-dimensional computed tomographic reconstruction …
2009
Abstract Background Postoperative venous congestion can lead to graft and remnant liver failure in living donor liver transplantation. This study was designed to delineate ‘territorial belonging’ of the middle hepatic vein (MHV) and to identify hepatic venous anatomy at high risk of outflow congestion. Methods MHV belonging patterns for right (RHL) and left (LHL) hemilivers were evaluated by three-dimensional computed tomographic reconstruction and virtual hepatectomy in 138 consecutive living liver donor candidates. Results The right hepatic vein (RHV) was dominant in 84·1 per cent and an accessory inferior hepatic vein (IHV) was present in 47·1 per cent of livers. Three MHV belonging type…
Decoding Musical Training from Dynamic Processing of Musical Features in the Brain
2018
AbstractPattern recognition on neural activations from naturalistic music listening has been successful at predicting neural responses of listeners from musical features, and vice versa. Inter-subject differences in the decoding accuracies have arisen partly from musical training that has widely recognized structural and functional effects on the brain. We propose and evaluate a decoding approach aimed at predicting the musicianship class of an individual listener from dynamic neural processing of musical features. Whole brain functional magnetic resonance imaging (fMRI) data was acquired from musicians and nonmusicians during listening of three musical pieces from different genres. Six mus…
Uncertainty quantification in simulations of epidemics using polynomial chaos.
2012
Mathematical models based on ordinary differential equations are a useful tool to study the processes involved in epidemiology. Many models consider that the parameters are deterministic variables. But in practice, the transmission parameters present large variability and it is not possible to determine them exactly, and it is necessary to introduce randomness. In this paper, we present an application of the polynomial chaos approach to epidemiological mathematical models based on ordinary differential equations with random coefficients. Taking into account the variability of the transmission parameters of the model, this approach allows us to obtain an auxiliary system of differential equa…
Recognition of Root Canal Orifices in Video Sequences as a Future Support System During Endodontic Treatment
2009
Abstract Introduction The objective of this study was to show the practical application of computer-aided techniques for detecting root canal orifices through the access cavity using a video camera mounted on a microscope. Methods A minimum distance classification image recognition algorithm was tested in an in vitro study to assess the possibilities of computer-aided recognition of root canal orifices. A Motic DM143 digital stereo microscope (Motic Germany GmbH, Wetzlar, Germany) was used because it includes a video camera that can be connected via USB1.1 to any computer. Results The newly developed software is capable of communicating with a video camera and can automatically detect the r…
Surrogate data approaches to assess the significance of directed coherence: Application to EEG activity propagation
2009
This paper addresses the topic of evaluating the significance of frequency domain measures of causal coupling in multivariate time series through generation of surrogate data. The considered approaches are the traditional Fourier Transform (FT) algorithm and a new causal FT (CFT) algorithm for surrogate data generation. Both algorithms preserve the FT modulus of the original series; differences are in the phase relationships, that are completely destroyed for FT surrogates and imposed after switching off the link over the considered causal direction for CFT surrogates. The ability of the algorithms to assess causality in the frequency domain was tested using the directed coherence as discri…
Testing Frequency-Domain Causality in Multivariate Time Series
2010
We introduce a new hypothesis-testing framework, based on surrogate data generation, to assess in the frequency domain, the concept of causality among multivariate (MV) time series. The approach extends the traditional Fourier transform (FT) method for generating surrogate data in a MV process and adapts it to the specific issue of causality. It generates causal FT (CFT) surrogates with FT modulus taken from the original series, and FT phase taken from a set of series with causal interactions set to zero over the direction of interest and preserved over all other directions. Two different zero-setting procedures, acting on the parameters of a MV autoregressive (MVAR) model fitted on the ori…
A multicenter phase III prospective randomized trial of high-dose epirubicin in combination with cyclophosphamide (EC) versus docetaxel followed by E…
2011
Background: The Gruppo Oncologico Italia Meridionale 9902 trial compared four cycles of high-dose epirubicin plus cyclophosphamide (EC) with four cycles of docetaxel (Taxotere, D) followed by four cycles of EC as adjuvant treatment of node-positive breast cancer. Patients and methods: Patients were randomly assigned to EC (E 120 mg/m 2 , C 600 mg/m 2 , arm A) for four cycles or four cycles of D (100 mg/m 2 ) followed by four cycles of EC (arm B), both regimens every 21 days. Hormone receptor-positive patients were given hormonal therapy for 5 years. Primary end point was 5-year disease-free survival (DFS). Secondary objectives were overall survival (OS) and safety. Results: There were 750 p…
Guía de práctica clínica: síndrome del intestino irritable con estreñimiento y estreñimiento funcional en adultos: concepto, diagnóstico y continuida…
2016
Resumen En esta Guía de práctica clínica analizamos el manejo diagnóstico y terapéutico de pacientes adultos con estreñimiento y molestias abdominales, bajo el espectro del síndrome del intestino irritable y el estreñimiento funcional. Tienen una importante repercusión personal, sanitaria y social, afectando a la calidad de vida de los pacientes que las padecen. En el síndrome del intestino irritable con predomino del estreñimiento, este es la alteración deposicional predominante junto con dolor abdominal recurrente, hinchazón y distensión abdominal frecuente. El estreñimiento se caracteriza por la dificultad o la escasa frecuencia en las deposiciones, acompañado por esfuerzo excesivo duran…
Non-invasive diagnosis in a case of bronchopulmonary sequestration and proposal of diagnostic algorhythm
2008
The case of a 43-year-old woman with intralobar pulmonary sequestration, Pryce type one, is presented. The medical history was characterised by recurrent bronchopneumonia, productive cough with purulent sputum and hemoptysis in the last three years. Diagnosis was made by CT angiography: multiplanar, maximum intensity projection and volume rendering reconstructions were visualised. A volume reduction of middle and lower lobe with multiple cyst-like bronchiectasis was detected and no evident relationship with tracheobronchial tree was pointed out. Reconstructions aimed at evaluating bronchial structures demonstrated no patency of middle and lower lobar bronchi. The study carried out after con…